Vendor import of llvm-project master e26a78e70, the last commit beforevendor/llvm-project/llvmorg-10-init-17466-ge26a78e7085

the llvmorg-11-init tag, from which release/10.x was branched.

157 files changed, 5513 insertions, 4959 deletions

diff --git a/lldb/source/Plugins/ABI/MacOSX-arm64/ABIMacOSX_arm64.cpp b/lldb/source/Plugins/ABI/MacOSX-arm64/ABIMacOSX_arm64.cpp
index 6473ccf9a19a..ec7588dfb50c 100644
--- a/lldb/source/Plugins/ABI/MacOSX-arm64/ABIMacOSX_arm64.cpp
+++ b/lldb/source/Plugins/ABI/MacOSX-arm64/ABIMacOSX_arm64.cpp
@@ -2020,6 +2020,8 @@ bool ABIMacOSX_arm64::CreateDefaultUnwindPlan(UnwindPlan &unwind_plan) {
 // registers x19 through x28 and sp are callee preserved. v8-v15 are non-
 // volatile (and specifically only the lower 8 bytes of these regs), the rest
 // of the fp/SIMD registers are volatile.
+//
+// v. https://github.com/ARM-software/software-standards/blob/master/abi/aapcs64/
 
 // We treat x29 as callee preserved also, else the unwinder won't try to
 // retrieve fp saves.
diff --git a/lldb/source/Plugins/Disassembler/llvm/DisassemblerLLVMC.cpp b/lldb/source/Plugins/Disassembler/llvm/DisassemblerLLVMC.cpp
index 28c9de2c1e96..dbdb3520087e 100644
--- a/lldb/source/Plugins/Disassembler/llvm/DisassemblerLLVMC.cpp
+++ b/lldb/source/Plugins/Disassembler/llvm/DisassemblerLLVMC.cpp
@@ -20,6 +20,7 @@
 #include "llvm/MC/MCInstrInfo.h"
 #include "llvm/MC/MCRegisterInfo.h"
 #include "llvm/MC/MCSubtargetInfo.h"
+#include "llvm/MC/MCTargetOptions.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/ScopedPrinter.h"
 #include "llvm/Support/TargetRegistry.h"
@@ -949,8 +950,9 @@ DisassemblerLLVMC::MCDisasmInstance::Create(const char *triple, const char *cpu,
   if (!subtarget_info_up)
     return Instance();
 
+  llvm::MCTargetOptions MCOptions;
   std::unique_ptr<llvm::MCAsmInfo> asm_info_up(
-      curr_target->createMCAsmInfo(*reg_info_up, triple));
+      curr_target->createMCAsmInfo(*reg_info_up, triple, MCOptions));
   if (!asm_info_up)
     return Instance();
 
@@ -1018,7 +1020,7 @@ uint64_t DisassemblerLLVMC::MCDisasmInstance::GetMCInst(
 
   uint64_t new_inst_size;
   status = m_disasm_up->getInstruction(mc_inst, new_inst_size, data, pc,
-                                       llvm::nulls(), llvm::nulls());
+                                       llvm::nulls());
   if (status == llvm::MCDisassembler::Success)
     return new_inst_size;
   else
@@ -1032,8 +1034,8 @@ void DisassemblerLLVMC::MCDisasmInstance::PrintMCInst(
   llvm::raw_string_ostream comments_stream(comments_string);
 
   m_instr_printer_up->setCommentStream(comments_stream);
-  m_instr_printer_up->printInst(&mc_inst, inst_stream, llvm::StringRef(),
-                                *m_subtarget_info_up);
+  m_instr_printer_up->printInst(&mc_inst, 0, llvm::StringRef(),
+                                *m_subtarget_info_up, inst_stream);
   m_instr_printer_up->setCommentStream(llvm::nulls());
   comments_stream.flush();
 
@@ -1212,7 +1214,7 @@ DisassemblerLLVMC::DisassemblerLLVMC(const ArchSpec &arch,
   if (llvm_arch == llvm::Triple::arm) {
     std::string thumb_triple(thumb_arch.GetTriple().getTriple());
     m_alternate_disasm_up =
-        MCDisasmInstance::Create(thumb_triple.c_str(), "", features_str.c_str(), 
+        MCDisasmInstance::Create(thumb_triple.c_str(), "", features_str.c_str(),
                                  flavor, *this);
     if (!m_alternate_disasm_up)
       m_disasm_up.reset();
diff --git a/lldb/source/Plugins/ExpressionParser/Clang/ASTDumper.cpp b/lldb/source/Plugins/ExpressionParser/Clang/ASTDumper.cpp
deleted file mode 100644
index f33a713cc0b2..000000000000
--- a/lldb/source/Plugins/ExpressionParser/Clang/ASTDumper.cpp
+++ /dev/null
@@ -1,104 +0,0 @@
-//===-- ASTDumper.cpp -------------------------------------------*- C++ -*-===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-
-#include "ASTDumper.h"
-
-#include "lldb/Symbol/ClangASTContext.h"
-#include "lldb/Symbol/ClangUtil.h"
-#include "lldb/Symbol/CompilerType.h"
-#include "lldb/Utility/Log.h"
-
-#include "llvm/Support/raw_ostream.h"
-
-using namespace lldb_private;
-
-ASTDumper::ASTDumper(clang::Decl *decl) {
-  clang::DeclContext *decl_ctx = llvm::dyn_cast<clang::DeclContext>(decl);
-
-  bool has_external_lexical_storage;
-  bool has_external_visible_storage;
-
-  if (decl_ctx) {
-    has_external_lexical_storage = decl_ctx->hasExternalLexicalStorage();
-    has_external_visible_storage = decl_ctx->hasExternalVisibleStorage();
-    decl_ctx->setHasExternalLexicalStorage(false);
-    decl_ctx->setHasExternalVisibleStorage(false);
-  }
-
-  llvm::raw_string_ostream os(m_dump);
-  decl->print(os);
-  os.flush();
-
-  if (decl_ctx) {
-    decl_ctx->setHasExternalLexicalStorage(has_external_lexical_storage);
-    decl_ctx->setHasExternalVisibleStorage(has_external_visible_storage);
-  }
-}
-
-ASTDumper::ASTDumper(clang::DeclContext *decl_ctx) {
-  bool has_external_lexical_storage = decl_ctx->hasExternalLexicalStorage();
-  bool has_external_visible_storage = decl_ctx->hasExternalVisibleStorage();
-
-  decl_ctx->setHasExternalLexicalStorage(false);
-  decl_ctx->setHasExternalVisibleStorage(false);
-
-  if (clang::Decl *decl = llvm::dyn_cast<clang::Decl>(decl_ctx)) {
-    llvm::raw_string_ostream os(m_dump);
-    decl->print(os);
-    os.flush();
-  } else {
-    m_dump.assign("<DeclContext is not a Decl>");
-  }
-
-  decl_ctx->setHasExternalLexicalStorage(has_external_lexical_storage);
-  decl_ctx->setHasExternalVisibleStorage(has_external_visible_storage);
-}
-
-ASTDumper::ASTDumper(const clang::Type *type) {
-  m_dump = clang::QualType(type, 0).getAsString();
-}
-
-ASTDumper::ASTDumper(clang::QualType type) { m_dump = type.getAsString(); }
-
-ASTDumper::ASTDumper(lldb::opaque_compiler_type_t type) {
-  m_dump = clang::QualType::getFromOpaquePtr(type).getAsString();
-}
-
-ASTDumper::ASTDumper(const CompilerType &compiler_type) {
-  m_dump = ClangUtil::GetQualType(compiler_type).getAsString();
-}
-
-const char *ASTDumper::GetCString() { return m_dump.c_str(); }
-
-void ASTDumper::ToLog(Log *log, const char *prefix) {
-  size_t len = m_dump.length() + 1;
-
-  char *alloc = (char *)malloc(len);
-  char *str = alloc;
-
-  memcpy(str, m_dump.c_str(), len);
-
-  char *end = nullptr;
-
-  end = strchr(str, '\n');
-
-  while (end) {
-    *end = '\0';
-
-    LLDB_LOGF(log, "%s%s", prefix, str);
-
-    *end = '\n';
-
-    str = end + 1;
-    end = strchr(str, '\n');
-  }
-
-  LLDB_LOGF(log, "%s%s", prefix, str);
-
-  free(alloc);
-}
diff --git a/lldb/source/Plugins/ExpressionParser/Clang/ASTDumper.h b/lldb/source/Plugins/ExpressionParser/Clang/ASTDumper.h
deleted file mode 100644
index ddf055d9c0c3..000000000000
--- a/lldb/source/Plugins/ExpressionParser/Clang/ASTDumper.h
+++ /dev/null
@@ -1,40 +0,0 @@
-//===-- ASTDumper.h ---------------------------------------------*- C++ -*-===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-
-#ifndef liblldb_ASTDumper_h_
-#define liblldb_ASTDumper_h_
-
-#include "clang/AST/DeclVisitor.h"
-#include "clang/AST/TypeVisitor.h"
-
-#include "lldb/Utility/Stream.h"
-#include "llvm/ADT/DenseSet.h"
-
-namespace lldb_private {
-
-class ASTDumper {
-public:
-  ASTDumper(clang::Decl *decl);
-  ASTDumper(clang::DeclContext *decl_ctx);
-  ASTDumper(const clang::Type *type);
-  ASTDumper(clang::QualType type);
-  ASTDumper(lldb::opaque_compiler_type_t type);
-  ASTDumper(const CompilerType &compiler_type);
-
-  const char *GetCString();
-  void ToSTDERR();
-  void ToLog(Log *log, const char *prefix);
-  void ToStream(lldb::StreamSP &stream);
-
-private:
-  std::string m_dump;
-};
-
-} // namespace lldb_private
-
-#endif
diff --git a/lldb/source/Plugins/ExpressionParser/Clang/ASTResultSynthesizer.cpp b/lldb/source/Plugins/ExpressionParser/Clang/ASTResultSynthesizer.cpp
index 68eaad33f51c..77bb9544ea40 100644
--- a/lldb/source/Plugins/ExpressionParser/Clang/ASTResultSynthesizer.cpp
+++ b/lldb/source/Plugins/ExpressionParser/Clang/ASTResultSynthesizer.cpp
@@ -388,8 +388,7 @@ bool ASTResultSynthesizer::SynthesizeBodyResult(CompoundStmt *Body,
   // replace the old statement with the new one
   //
 
-  *last_stmt_ptr =
-      reinterpret_cast<Stmt *>(result_initialization_stmt_result.get());
+  *last_stmt_ptr = static_cast<Stmt *>(result_initialization_stmt_result.get());
 
   return true;
 }
@@ -448,13 +447,20 @@ void ASTResultSynthesizer::RecordPersistentDecl(NamedDecl *D) {
 }
 
 void ASTResultSynthesizer::CommitPersistentDecls() {
+  auto *state =
+      m_target.GetPersistentExpressionStateForLanguage(lldb::eLanguageTypeC);
+  if (!state)
+    return;
+
+  auto *persistent_vars = llvm::cast<ClangPersistentVariables>(state);
+  ClangASTContext *scratch_ctx = ClangASTContext::GetScratch(m_target);
+
   for (clang::NamedDecl *decl : m_decls) {
     StringRef name = decl->getName();
     ConstString name_cs(name.str().c_str());
 
     Decl *D_scratch = m_target.GetClangASTImporter()->DeportDecl(
-        m_target.GetScratchClangASTContext()->getASTContext(), m_ast_context,
-        decl);
+        &scratch_ctx->getASTContext(), decl);
 
     if (!D_scratch) {
       Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS));
@@ -472,10 +478,8 @@ void ASTResultSynthesizer::CommitPersistentDecls() {
     }
 
     if (NamedDecl *NamedDecl_scratch = dyn_cast<NamedDecl>(D_scratch))
-      llvm::cast<ClangPersistentVariables>(
-          m_target.GetPersistentExpressionStateForLanguage(
-              lldb::eLanguageTypeC))
-          ->RegisterPersistentDecl(name_cs, NamedDecl_scratch);
+      persistent_vars->RegisterPersistentDecl(name_cs, NamedDecl_scratch,
+                                              scratch_ctx);
   }
 }
 
diff --git a/lldb/source/Plugins/ExpressionParser/Clang/ASTResultSynthesizer.h b/lldb/source/Plugins/ExpressionParser/Clang/ASTResultSynthesizer.h
index 670ba6dce72e..0b0f3b97705d 100644
--- a/lldb/source/Plugins/ExpressionParser/Clang/ASTResultSynthesizer.h
+++ b/lldb/source/Plugins/ExpressionParser/Clang/ASTResultSynthesizer.h
@@ -135,18 +135,11 @@ private:
   void RecordPersistentTypes(clang::DeclContext *FunDeclCtx);
 
   /// Given a TypeDecl, if it declares a type whose name starts with a dollar
-  /// sign, register it as a pointer type in the target's scratch
-  /// AST context.
-  ///
-  /// \param[in] Body
-  ///     The body of the function.
+  /// sign, register it as a pointer type in the target's scratch AST context.
   void MaybeRecordPersistentType(clang::TypeDecl *D);
 
   /// Given a NamedDecl, register it as a pointer type in the target's scratch
   /// AST context.
-  ///
-  /// \param[in] Body
-  ///     The body of the function.
   void RecordPersistentDecl(clang::NamedDecl *D);
 
   clang::ASTContext
diff --git a/lldb/source/Plugins/ExpressionParser/Clang/ASTStructExtractor.cpp b/lldb/source/Plugins/ExpressionParser/Clang/ASTStructExtractor.cpp
index 190eacaa2b62..a164d48ae3e0 100644
--- a/lldb/source/Plugins/ExpressionParser/Clang/ASTStructExtractor.cpp
+++ b/lldb/source/Plugins/ExpressionParser/Clang/ASTStructExtractor.cpp
@@ -30,8 +30,8 @@ ASTStructExtractor::ASTStructExtractor(ASTConsumer *passthrough,
                                        const char *struct_name,
                                        ClangFunctionCaller &function)
     : m_ast_context(nullptr), m_passthrough(passthrough),
-      m_passthrough_sema(nullptr), m_sema(nullptr), m_action(nullptr),
-      m_function(function), m_struct_name(struct_name) {
+      m_passthrough_sema(nullptr), m_sema(nullptr), m_function(function),
+      m_struct_name(struct_name) {
   if (!m_passthrough)
     return;
 
@@ -170,7 +170,6 @@ void ASTStructExtractor::PrintStats() {
 
 void ASTStructExtractor::InitializeSema(Sema &S) {
   m_sema = &S;
-  m_action = reinterpret_cast<Action *>(m_sema);
 
   if (m_passthrough_sema)
     m_passthrough_sema->InitializeSema(S);
@@ -178,7 +177,6 @@ void ASTStructExtractor::InitializeSema(Sema &S) {
 
 void ASTStructExtractor::ForgetSema() {
   m_sema = nullptr;
-  m_action = nullptr;
 
   if (m_passthrough_sema)
     m_passthrough_sema->ForgetSema();
diff --git a/lldb/source/Plugins/ExpressionParser/Clang/ASTStructExtractor.h b/lldb/source/Plugins/ExpressionParser/Clang/ASTStructExtractor.h
index 7aef2e254e1f..078cf095975f 100644
--- a/lldb/source/Plugins/ExpressionParser/Clang/ASTStructExtractor.h
+++ b/lldb/source/Plugins/ExpressionParser/Clang/ASTStructExtractor.h
@@ -121,8 +121,6 @@ private:
                                            ///for passthrough.  NULL if it's an
                                            ///ASTConsumer.
   clang::Sema *m_sema;                     ///< The Sema to use.
-  clang::Action
-      *m_action; ///< The Sema to use, cast to an Action so it's usable.
 
   ClangFunctionCaller &m_function; ///< The function to populate with
                                    ///information about the argument structure.
diff --git a/lldb/source/Plugins/ExpressionParser/Clang/ClangASTSource.cpp b/lldb/source/Plugins/ExpressionParser/Clang/ClangASTSource.cpp
index 372c2439ebf0..42927ab6cc8a 100644
--- a/lldb/source/Plugins/ExpressionParser/Clang/ClangASTSource.cpp
+++ b/lldb/source/Plugins/ExpressionParser/Clang/ClangASTSource.cpp
@@ -8,7 +8,6 @@
 
 #include "ClangASTSource.h"
 
-#include "ASTDumper.h"
 #include "ClangDeclVendor.h"
 #include "ClangModulesDeclVendor.h"
 
@@ -50,114 +49,42 @@ private:
 };
 }
 
-ClangASTSource::ClangASTSource(const lldb::TargetSP &target)
+ClangASTSource::ClangASTSource(const lldb::TargetSP &target,
+                               const lldb::ClangASTImporterSP &importer)
     : m_import_in_progress(false), m_lookups_enabled(false), m_target(target),
       m_ast_context(nullptr), m_active_lexical_decls(), m_active_lookups() {
-  if (!target->GetUseModernTypeLookup()) {
-    m_ast_importer_sp = m_target->GetClangASTImporter();
-  }
+  m_ast_importer_sp = importer;
 }
 
-void ClangASTSource::InstallASTContext(clang::ASTContext &ast_context,
-                                       clang::FileManager &file_manager,
-                                       bool is_shared_context) {
-  m_ast_context = &ast_context;
-  m_file_manager = &file_manager;
-  if (m_target->GetUseModernTypeLookup()) {
-    // Configure the ExternalASTMerger.  The merger needs to be able to import
-    // types from any source that we would do lookups in, which includes the
-    // persistent AST context as well as the modules and Objective-C runtime
-    // AST contexts.
-
-    lldbassert(!m_merger_up);
-    clang::ExternalASTMerger::ImporterTarget target = {ast_context,
-                                                       file_manager};
-    std::vector<clang::ExternalASTMerger::ImporterSource> sources;
-    for (lldb::ModuleSP module_sp : m_target->GetImages().Modules()) {
-      auto type_system_or_err =
-          module_sp->GetTypeSystemForLanguage(lldb::eLanguageTypeC);
-      if (auto err = type_system_or_err.takeError()) {
-        LLDB_LOG_ERROR(
-            lldb_private::GetLogIfAnyCategoriesSet(LIBLLDB_LOG_EXPRESSIONS),
-            std::move(err), "Failed to get ClangASTContext");
-      } else if (auto *module_ast_ctx = llvm::cast_or_null<ClangASTContext>(
-                     &type_system_or_err.get())) {
-        lldbassert(module_ast_ctx->getASTContext());
-        lldbassert(module_ast_ctx->getFileManager());
-        sources.emplace_back(*module_ast_ctx->getASTContext(),
-                             *module_ast_ctx->getFileManager(),
-                             module_ast_ctx->GetOriginMap());
-      }
-    }
-
-    do {
-      lldb::ProcessSP process(m_target->GetProcessSP());
-
-      if (!process)
-        break;
-
-      ObjCLanguageRuntime *language_runtime(ObjCLanguageRuntime::Get(*process));
-
-      if (!language_runtime)
-        break;
-
-      if (auto *runtime_decl_vendor = llvm::dyn_cast_or_null<ClangDeclVendor>(
-              language_runtime->GetDeclVendor())) {
-        sources.push_back(runtime_decl_vendor->GetImporterSource());
-      }
-    } while (false);
-
-    do {
-      auto *modules_decl_vendor = m_target->GetClangModulesDeclVendor();
-
-      if (!modules_decl_vendor)
-        break;
-
-      sources.push_back(modules_decl_vendor->GetImporterSource());
-    } while (false);
-
-    if (!is_shared_context) {
-      // Update the scratch AST context's merger to reflect any new sources we
-      // might have come across since the last time an expression was parsed.
-
-      auto scratch_ast_context = static_cast<ClangASTContextForExpressions*>(
-          m_target->GetScratchClangASTContext());
-
-      scratch_ast_context->GetMergerUnchecked().AddSources(sources);
-
-      sources.push_back({*scratch_ast_context->getASTContext(),
-                         *scratch_ast_context->getFileManager(),
-                         scratch_ast_context->GetOriginMap()});
-    }
-
-    m_merger_up =
-        std::make_unique<clang::ExternalASTMerger>(target, sources);
-  } else {
-    m_ast_importer_sp->InstallMapCompleter(&ast_context, *this);
-  }
+void ClangASTSource::InstallASTContext(ClangASTContext &clang_ast_context) {
+  m_ast_context = &clang_ast_context.getASTContext();
+  m_clang_ast_context = &clang_ast_context;
+  m_file_manager = &m_ast_context->getSourceManager().getFileManager();
+  m_ast_importer_sp->InstallMapCompleter(m_ast_context, *this);
 }
 
 ClangASTSource::~ClangASTSource() {
-  if (m_ast_importer_sp)
-    m_ast_importer_sp->ForgetDestination(m_ast_context);
+  if (!m_ast_importer_sp)
+    return;
+
+  m_ast_importer_sp->ForgetDestination(m_ast_context);
 
+  if (!m_target)
+    return;
   // We are in the process of destruction, don't create clang ast context on
   // demand by passing false to
   // Target::GetScratchClangASTContext(create_on_demand).
   ClangASTContext *scratch_clang_ast_context =
-      m_target->GetScratchClangASTContext(false);
+      ClangASTContext::GetScratch(*m_target, false);
 
   if (!scratch_clang_ast_context)
     return;
 
-  clang::ASTContext *scratch_ast_context =
+  clang::ASTContext &scratch_ast_context =
       scratch_clang_ast_context->getASTContext();
 
-  if (!scratch_ast_context)
-    return;
-
-  if (m_ast_context != scratch_ast_context && m_ast_importer_sp)
-    m_ast_importer_sp->ForgetSource(scratch_ast_context, m_ast_context);
+  if (m_ast_context != &scratch_ast_context && m_ast_importer_sp)
+    m_ast_importer_sp->ForgetSource(&scratch_ast_context, m_ast_context);
 }
 
 void ClangASTSource::StartTranslationUnit(ASTConsumer *Consumer) {
@@ -279,9 +206,8 @@ void ClangASTSource::CompleteType(TagDecl *tag_decl) {
               current_id, static_cast<void *>(m_ast_context),
               static_cast<void *>(tag_decl), tag_decl->getName().str().c_str());
 
-    LLDB_LOGF(log, "      CTD[%u] Before:", current_id);
-    ASTDumper dumper((Decl *)tag_decl);
-    dumper.ToLog(log, "      [CTD] ");
+    LLDB_LOG(log, "      CTD[%u] Before:\n{0}", current_id,
+             ClangUtil::DumpDecl(tag_decl));
   }
 
   auto iter = m_active_lexical_decls.find(tag_decl);
@@ -291,9 +217,6 @@ void ClangASTSource::CompleteType(TagDecl *tag_decl) {
   ScopedLexicalDeclEraser eraser(m_active_lexical_decls, tag_decl);
 
   if (!m_ast_importer_sp) {
-    if (HasMerger()) {
-      GetMergerUnchecked().CompleteType(tag_decl);
-    }
     return;
   }
 
@@ -365,7 +288,6 @@ void ClangASTSource::CompleteType(TagDecl *tag_decl) {
       TypeList types;
 
       ConstString name(tag_decl->getName().str().c_str());
-      CompilerDeclContext namespace_decl;
 
       const ModuleList &module_list = m_target->GetImages();
 
@@ -407,50 +329,30 @@ void ClangASTSource::CompleteType(TagDecl *tag_decl) {
     }
   }
 
-  if (log) {
-    LLDB_LOGF(log, "      [CTD] After:");
-    ASTDumper dumper((Decl *)tag_decl);
-    dumper.ToLog(log, "      [CTD] ");
-  }
+  LLDB_LOG(log, "      [CTD] After:\n{0}", ClangUtil::DumpDecl(tag_decl));
 }
 
 void ClangASTSource::CompleteType(clang::ObjCInterfaceDecl *interface_decl) {
   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS));
 
-  if (log) {
-    LLDB_LOGF(log,
-              "    [CompleteObjCInterfaceDecl] on (ASTContext*)%p Completing "
-              "an ObjCInterfaceDecl named %s",
-              static_cast<void *>(m_ast_context),
-              interface_decl->getName().str().c_str());
-    LLDB_LOGF(log, "      [COID] Before:");
-    ASTDumper dumper((Decl *)interface_decl);
-    dumper.ToLog(log, "      [COID] ");
-  }
+  LLDB_LOGF(log,
+            "    [CompleteObjCInterfaceDecl] on (ASTContext*)%p Completing "
+            "an ObjCInterfaceDecl named %s",
+            static_cast<void *>(m_ast_context),
+            interface_decl->getName().str().c_str());
+  LLDB_LOG(log, "      [COID] Before:\n{0}",
+           ClangUtil::DumpDecl(interface_decl));
 
   if (!m_ast_importer_sp) {
-    if (HasMerger()) {
-      ObjCInterfaceDecl *complete_iface_decl =
-        GetCompleteObjCInterface(interface_decl);
-
-      if (complete_iface_decl && (complete_iface_decl != interface_decl)) {
-        m_merger_up->ForceRecordOrigin(interface_decl, {complete_iface_decl, &complete_iface_decl->getASTContext()});
-      }
-
-      GetMergerUnchecked().CompleteType(interface_decl);
-    } else {
-      lldbassert(0 && "No mechanism for completing a type!");
-    }
+    lldbassert(0 && "No mechanism for completing a type!");
     return;
   }
 
-  Decl *original_decl = nullptr;
-  ASTContext *original_ctx = nullptr;
+  ClangASTImporter::DeclOrigin original = m_ast_importer_sp->GetDeclOrigin(interface_decl);
 
-  if (m_ast_importer_sp->ResolveDeclOrigin(interface_decl, &original_decl,
-                                           &original_ctx)) {
+  if (original.Valid()) {
     if (ObjCInterfaceDecl *original_iface_decl =
-            dyn_cast<ObjCInterfaceDecl>(original_decl)) {
+            dyn_cast<ObjCInterfaceDecl>(original.decl)) {
       ObjCInterfaceDecl *complete_iface_decl =
           GetCompleteObjCInterface(original_iface_decl);
 
@@ -468,8 +370,7 @@ void ClangASTSource::CompleteType(clang::ObjCInterfaceDecl *interface_decl) {
 
   if (log) {
     LLDB_LOGF(log, "      [COID] After:");
-    ASTDumper dumper((Decl *)interface_decl);
-    dumper.ToLog(log, "      [COID] ");
+    LLDB_LOG(log, "      [COID] {0}", ClangUtil::DumpDecl(interface_decl));
   }
 }
 
@@ -519,23 +420,9 @@ void ClangASTSource::FindExternalLexicalDecls(
     llvm::function_ref<bool(Decl::Kind)> predicate,
     llvm::SmallVectorImpl<Decl *> &decls) {
 
-  if (HasMerger()) {
-    if (auto *interface_decl = dyn_cast<ObjCInterfaceDecl>(decl_context)) {
-      ObjCInterfaceDecl *complete_iface_decl =
-         GetCompleteObjCInterface(interface_decl);
-
-      if (complete_iface_decl && (complete_iface_decl != interface_decl)) {
-        m_merger_up->ForceRecordOrigin(interface_decl, {complete_iface_decl, &complete_iface_decl->getASTContext()});
-      }
-    }
-    return GetMergerUnchecked().FindExternalLexicalDecls(decl_context,
-                                                         predicate,
-                                                         decls);
-  } else if (!m_ast_importer_sp)
+  if (!m_ast_importer_sp)
     return;
 
-  ClangASTMetrics::RegisterLexicalQuery();
-
   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS));
 
   const Decl *context_decl = dyn_cast<Decl>(decl_context);
@@ -574,42 +461,38 @@ void ClangASTSource::FindExternalLexicalDecls(
           current_id, static_cast<const void *>(m_ast_context));
   }
 
-  Decl *original_decl = nullptr;
-  ASTContext *original_ctx = nullptr;
+  ClangASTImporter::DeclOrigin original = m_ast_importer_sp->GetDeclOrigin(context_decl);
 
-  if (!m_ast_importer_sp->ResolveDeclOrigin(context_decl, &original_decl,
-                                            &original_ctx))
+  if (!original.Valid())
     return;
 
-  if (log) {
-    LLDB_LOGF(
-        log, "  FELD[%u] Original decl (ASTContext*)%p (Decl*)%p:", current_id,
-        static_cast<void *>(original_ctx), static_cast<void *>(original_decl));
-    ASTDumper(original_decl).ToLog(log, "    ");
-  }
+  LLDB_LOG(
+      log, "  FELD[{0}] Original decl (ASTContext*){1:x} (Decl*){2:x}:\n{3}",
+      current_id, static_cast<void *>(original.ctx),
+      static_cast<void *>(original.decl), ClangUtil::DumpDecl(original.decl));
 
   if (ObjCInterfaceDecl *original_iface_decl =
-          dyn_cast<ObjCInterfaceDecl>(original_decl)) {
+          dyn_cast<ObjCInterfaceDecl>(original.decl)) {
     ObjCInterfaceDecl *complete_iface_decl =
         GetCompleteObjCInterface(original_iface_decl);
 
     if (complete_iface_decl && (complete_iface_decl != original_iface_decl)) {
-      original_decl = complete_iface_decl;
-      original_ctx = &complete_iface_decl->getASTContext();
+      original.decl = complete_iface_decl;
+      original.ctx = &complete_iface_decl->getASTContext();
 
       m_ast_importer_sp->SetDeclOrigin(context_decl, complete_iface_decl);
     }
   }
 
-  if (TagDecl *original_tag_decl = dyn_cast<TagDecl>(original_decl)) {
-    ExternalASTSource *external_source = original_ctx->getExternalSource();
+  if (TagDecl *original_tag_decl = dyn_cast<TagDecl>(original.decl)) {
+    ExternalASTSource *external_source = original.ctx->getExternalSource();
 
     if (external_source)
       external_source->CompleteType(original_tag_decl);
   }
 
   const DeclContext *original_decl_context =
-      dyn_cast<DeclContext>(original_decl);
+      dyn_cast<DeclContext>(original.decl);
 
   if (!original_decl_context)
     return;
@@ -625,16 +508,16 @@ void ClangASTSource::FindExternalLexicalDecls(
     // See clang::ExternalASTSource::FindExternalLexicalDecls()
     if (predicate(decl->getKind())) {
       if (log) {
-        ASTDumper ast_dumper(decl);
+        std::string ast_dump = ClangUtil::DumpDecl(decl);
         if (const NamedDecl *context_named_decl =
                 dyn_cast<NamedDecl>(context_decl))
           LLDB_LOGF(log, "  FELD[%d] Adding [to %sDecl %s] lexical %sDecl %s",
                     current_id, context_named_decl->getDeclKindName(),
                     context_named_decl->getNameAsString().c_str(),
-                    decl->getDeclKindName(), ast_dumper.GetCString());
+                    decl->getDeclKindName(), ast_dump.c_str());
         else
           LLDB_LOGF(log, "  FELD[%d] Adding lexical %sDecl %s", current_id,
-                    decl->getDeclKindName(), ast_dumper.GetCString());
+                    decl->getDeclKindName(), ast_dump.c_str());
       }
 
       Decl *copied_decl = CopyDecl(decl);
@@ -647,20 +530,6 @@ void ClangASTSource::FindExternalLexicalDecls(
 
         m_ast_importer_sp->RequireCompleteType(copied_field_type);
       }
-      auto decl_context_non_const = const_cast<DeclContext *>(decl_context);
-
-      // The decl ended up in the wrong DeclContext. Let's fix that so
-      // the decl we copied will actually be found.
-      // FIXME: This is a horrible hack that shouldn't be necessary. However
-      // it seems our current setup sometimes fails to copy decls to the right
-      // place. See rdar://55129537.
-      if (copied_decl->getDeclContext() != decl_context) {
-        assert(copied_decl->getDeclContext()->containsDecl(copied_decl));
-        copied_decl->getDeclContext()->removeDecl(copied_decl);
-        copied_decl->setDeclContext(decl_context_non_const);
-        assert(!decl_context_non_const->containsDecl(copied_decl));
-        decl_context_non_const->addDeclInternal(copied_decl);
-      }
     } else {
       SkippedDecls = true;
     }
@@ -683,8 +552,6 @@ void ClangASTSource::FindExternalLexicalDecls(
 void ClangASTSource::FindExternalVisibleDecls(NameSearchContext &context) {
   assert(m_ast_context);
 
-  ClangASTMetrics::RegisterVisibleQuery();
-
   const ConstString name(context.m_decl_name.getAsString().c_str());
 
   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS));
@@ -715,25 +582,6 @@ void ClangASTSource::FindExternalVisibleDecls(NameSearchContext &context) {
                 name.GetCString(), context.m_decl_context->getDeclKindName());
   }
 
-  if (HasMerger() && !isa<TranslationUnitDecl>(context.m_decl_context)
-      /* possibly handle NamespaceDecls here? */) {
-    if (auto *interface_decl =
-    dyn_cast<ObjCInterfaceDecl>(context.m_decl_context)) {
-      ObjCInterfaceDecl *complete_iface_decl =
-      GetCompleteObjCInterface(interface_decl);
-
-      if (complete_iface_decl && (complete_iface_decl != interface_decl)) {
-        GetMergerUnchecked().ForceRecordOrigin(
-            interface_decl,
-            {complete_iface_decl, &complete_iface_decl->getASTContext()});
-      }
-    }
-
-    GetMergerUnchecked().FindExternalVisibleDeclsByName(context.m_decl_context,
-                                                context.m_decl_name);
-    return; // otherwise we may need to fall back
-  }
-
   context.m_namespace_map = std::make_shared<ClangASTImporter::NamespaceMap>();
 
   if (const NamespaceDecl *namespace_context =
@@ -758,7 +606,7 @@ void ClangASTSource::FindExternalVisibleDecls(NameSearchContext &context) {
 
       FindExternalVisibleDecls(context, i->first, i->second, current_id);
     }
-  } else if (isa<ObjCInterfaceDecl>(context.m_decl_context) && !HasMerger()) {
+  } else if (isa<ObjCInterfaceDecl>(context.m_decl_context)) {
     FindObjCPropertyAndIvarDecls(context);
   } else if (!isa<TranslationUnitDecl>(context.m_decl_context)) {
     // we shouldn't be getting FindExternalVisibleDecls calls for these
@@ -788,7 +636,7 @@ void ClangASTSource::FindExternalVisibleDecls(NameSearchContext &context) {
 }
 
 clang::Sema *ClangASTSource::getSema() {
-  return ClangASTContext::GetASTContext(m_ast_context)->getSema();
+  return m_clang_ast_context->getSema();
 }
 
 bool ClangASTSource::IgnoreName(const ConstString name,
@@ -821,6 +669,9 @@ void ClangASTSource::FindExternalVisibleDecls(
   if (IgnoreName(name, true))
     return;
 
+  if (!m_target)
+    return;
+
   if (module_sp && namespace_decl) {
     CompilerDeclContext found_namespace_decl;
 
@@ -837,7 +688,7 @@ void ClangASTSource::FindExternalVisibleDecls(
                   module_sp->GetFileSpec().GetFilename().GetCString());
       }
     }
-  } else if (!HasMerger()) {
+  } else {
     const ModuleList &target_images = m_target->GetImages();
     std::lock_guard<std::recursive_mutex> guard(target_images.GetMutex());
 
@@ -1049,11 +900,10 @@ public:
 
 template <class D>
 DeclFromUser<D> DeclFromParser<D>::GetOrigin(ClangASTSource &source) {
-  DeclFromUser<> origin_decl;
-  source.ResolveDeclOrigin(this->decl, &origin_decl.decl, nullptr);
-  if (origin_decl.IsInvalid())
+  ClangASTImporter::DeclOrigin origin = source.GetDeclOrigin(this->decl);
+  if (!origin.Valid())
     return DeclFromUser<D>();
-  return DeclFromUser<D>(dyn_cast<D>(origin_decl.decl));
+  return DeclFromUser<D>(dyn_cast<D>(origin.decl));
 }
 
 template <class D>
@@ -1137,11 +987,8 @@ bool ClangASTSource::FindObjCMethodDeclsWithOrigin(
 
     Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS));
 
-    if (log) {
-      ASTDumper dumper((Decl *)copied_method_decl);
-      LLDB_LOGF(log, "  CAS::FOMD[%d] found (%s) %s", current_id, log_info,
-                dumper.GetCString());
-    }
+    LLDB_LOG(log, "  CAS::FOMD[{0}] found ({1}) {2}", current_id, log_info,
+             ClangUtil::DumpDecl(copied_method_decl));
 
     context.AddNamedDecl(copied_method_decl);
   }
@@ -1152,21 +999,6 @@ bool ClangASTSource::FindObjCMethodDeclsWithOrigin(
 void ClangASTSource::FindObjCMethodDecls(NameSearchContext &context) {
   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS));
 
-  if (HasMerger()) {
-    if (auto *interface_decl = dyn_cast<ObjCInterfaceDecl>(context.m_decl_context)) {
-      ObjCInterfaceDecl *complete_iface_decl =
-          GetCompleteObjCInterface(interface_decl);
-
-      if (complete_iface_decl && (complete_iface_decl != context.m_decl_context)) {
-        m_merger_up->ForceRecordOrigin(interface_decl, {complete_iface_decl, &complete_iface_decl->getASTContext()});
-      }
-    }
-
-    GetMergerUnchecked().FindExternalVisibleDeclsByName(context.m_decl_context,
-                                                        context.m_decl_name);
-    return;
-  }
-
   static unsigned int invocation_id = 0;
   unsigned int current_id = invocation_id++;
 
@@ -1180,17 +1012,13 @@ void ClangASTSource::FindObjCMethodDecls(NameSearchContext &context) {
     return;
 
   do {
-    Decl *original_decl = nullptr;
-    ASTContext *original_ctx = nullptr;
-
-    m_ast_importer_sp->ResolveDeclOrigin(interface_decl, &original_decl,
-                                         &original_ctx);
+    ClangASTImporter::DeclOrigin original = m_ast_importer_sp->GetDeclOrigin(interface_decl);
 
-    if (!original_decl)
+    if (!original.Valid())
       break;
 
     ObjCInterfaceDecl *original_interface_decl =
-        dyn_cast<ObjCInterfaceDecl>(original_decl);
+        dyn_cast<ObjCInterfaceDecl>(original.decl);
 
     if (FindObjCMethodDeclsWithOrigin(current_id, context,
                                       original_interface_decl, "at origin"))
@@ -1343,11 +1171,8 @@ void ClangASTSource::FindObjCMethodDecls(NameSearchContext &context) {
         if (!copied_method_decl)
           continue;
 
-        if (log) {
-          ASTDumper dumper((Decl *)copied_method_decl);
-          LLDB_LOGF(log, "  CAS::FOMD[%d] found (in symbols) %s", current_id,
-                    dumper.GetCString());
-        }
+        LLDB_LOG(log, "  CAS::FOMD[{0}] found (in symbols)\n{1}", current_id,
+                 ClangUtil::DumpDecl(copied_method_decl));
 
         context.AddNamedDecl(copied_method_decl);
       }
@@ -1476,11 +1301,8 @@ static bool FindObjCPropertyAndIvarDeclsWithOrigin(
     DeclFromParser<ObjCPropertyDecl> parser_property_decl(
         origin_property_decl.Import(source));
     if (parser_property_decl.IsValid()) {
-      if (log) {
-        ASTDumper dumper((Decl *)parser_property_decl.decl);
-        LLDB_LOGF(log, "  CAS::FOPD[%d] found %s", current_id,
-                  dumper.GetCString());
-      }
+      LLDB_LOG(log, "  CAS::FOPD[{0}] found\n{1}", current_id,
+               ClangUtil::DumpDecl(parser_property_decl.decl));
 
       context.AddNamedDecl(parser_property_decl.decl);
       found = true;
@@ -1495,9 +1317,8 @@ static bool FindObjCPropertyAndIvarDeclsWithOrigin(
         origin_ivar_decl.Import(source));
     if (parser_ivar_decl.IsValid()) {
       if (log) {
-        ASTDumper dumper((Decl *)parser_ivar_decl.decl);
-        LLDB_LOGF(log, "  CAS::FOPD[%d] found %s", current_id,
-                  dumper.GetCString());
+        LLDB_LOG(log, "  CAS::FOPD[{0}] found\n{1}", current_id,
+                 ClangUtil::DumpDecl(parser_ivar_decl.decl));
       }
 
       context.AddNamedDecl(parser_ivar_decl.decl);
@@ -1736,8 +1557,6 @@ bool ClangASTSource::layoutRecordType(const RecordDecl *record, uint64_t &size,
                                       FieldOffsetMap &field_offsets,
                                       BaseOffsetMap &base_offsets,
                                       BaseOffsetMap &virtual_base_offsets) {
-  ClangASTMetrics::RegisterRecordLayout();
-
   static unsigned int invocation_id = 0;
   unsigned int current_id = invocation_id++;
 
@@ -1984,90 +1803,37 @@ NamespaceDecl *ClangASTSource::AddNamespace(
   return dyn_cast<NamespaceDecl>(copied_decl);
 }
 
-clang::QualType ClangASTSource::CopyTypeWithMerger(
-    clang::ASTContext &from_context,
-    clang::ExternalASTMerger &merger,
-    clang::QualType type) {
-  if (!merger.HasImporterForOrigin(from_context)) {
-    lldbassert(0 && "Couldn't find the importer for a source context!");
-    return QualType();
-  }
-
-  if (llvm::Expected<QualType> type_or_error =
-          merger.ImporterForOrigin(from_context).Import(type)) {
-    return *type_or_error;
-  } else {
-    Log *log = lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS);
-    LLDB_LOG_ERROR(log, type_or_error.takeError(), "Couldn't import type: {0}");
-    return QualType();
-  }
-}
-
 clang::Decl *ClangASTSource::CopyDecl(Decl *src_decl) {
-  clang::ASTContext &from_context = src_decl->getASTContext();
   if (m_ast_importer_sp) {
-    return m_ast_importer_sp->CopyDecl(m_ast_context, &from_context, src_decl);
-  } else if (m_merger_up) {
-    if (!m_merger_up->HasImporterForOrigin(from_context)) {
-      lldbassert(0 && "Couldn't find the importer for a source context!");
-      return nullptr;
-    }
-
-    if (llvm::Expected<Decl *> decl_or_error =
-            m_merger_up->ImporterForOrigin(from_context).Import(src_decl)) {
-      return *decl_or_error;
-    } else {
-      Log *log =
-          lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS);
-      LLDB_LOG_ERROR(log, decl_or_error.takeError(),
-                     "Couldn't import decl: {0}");
-      return nullptr;
-    }
+    return m_ast_importer_sp->CopyDecl(m_ast_context, src_decl);
   } else {
     lldbassert(0 && "No mechanism for copying a decl!");
     return nullptr;
   }
 }
 
-bool ClangASTSource::ResolveDeclOrigin(const clang::Decl *decl,
-                                       clang::Decl **original_decl,
-                                       clang::ASTContext **original_ctx) {
+ClangASTImporter::DeclOrigin ClangASTSource::GetDeclOrigin(const clang::Decl *decl) {
   if (m_ast_importer_sp) {
-    return m_ast_importer_sp->ResolveDeclOrigin(decl, original_decl,
-                                                original_ctx);
-  } else if (m_merger_up) {
-    return false; // Implement this correctly in ExternalASTMerger
+    return m_ast_importer_sp->GetDeclOrigin(decl);
   } else {
     // this can happen early enough that no ExternalASTSource is installed.
-    return false;
+    return ClangASTImporter::DeclOrigin();
   }
 }
 
-clang::ExternalASTMerger &ClangASTSource::GetMergerUnchecked() {
-  lldbassert(m_merger_up != nullptr);
-  return *m_merger_up;
-}
-
 CompilerType ClangASTSource::GuardedCopyType(const CompilerType &src_type) {
   ClangASTContext *src_ast =
       llvm::dyn_cast_or_null<ClangASTContext>(src_type.GetTypeSystem());
   if (src_ast == nullptr)
     return CompilerType();
 
-  ClangASTMetrics::RegisterLLDBImport();
-
   SetImportInProgress(true);
 
   QualType copied_qual_type;
 
   if (m_ast_importer_sp) {
-    copied_qual_type =
-        m_ast_importer_sp->CopyType(m_ast_context, src_ast->getASTContext(),
-                                    ClangUtil::GetQualType(src_type));
-  } else if (m_merger_up) {
-    copied_qual_type =
-        CopyTypeWithMerger(*src_ast->getASTContext(), *m_merger_up,
-                 ClangUtil::GetQualType(src_type));
+    copied_qual_type = ClangUtil::GetQualType(
+        m_ast_importer_sp->CopyType(*m_clang_ast_context, src_type));
   } else {
     lldbassert(0 && "No mechanism for copying a type!");
     return CompilerType();
@@ -2081,8 +1847,7 @@ CompilerType ClangASTSource::GuardedCopyType(const CompilerType &src_type) {
     // seems to be generating bad types on occasion.
     return CompilerType();
 
-  return CompilerType(ClangASTContext::GetASTContext(m_ast_context),
-                      copied_qual_type.getAsOpaquePtr());
+  return m_clang_ast_context->GetType(copied_qual_type);
 }
 
 clang::NamedDecl *NameSearchContext::AddVarDecl(const CompilerType &type) {
@@ -2098,10 +1863,10 @@ clang::NamedDecl *NameSearchContext::AddVarDecl(const CompilerType &type) {
 
   IdentifierInfo *ii = m_decl_name.getAsIdentifierInfo();
 
-  clang::ASTContext *ast = lldb_ast->getASTContext();
+  clang::ASTContext &ast = lldb_ast->getASTContext();
 
   clang::NamedDecl *Decl = VarDecl::Create(
-      *ast, const_cast<DeclContext *>(m_decl_context), SourceLocation(),
+      ast, const_cast<DeclContext *>(m_decl_context), SourceLocation(),
       SourceLocation(), ii, ClangUtil::GetQualType(type), nullptr, SC_Static);
   m_decls.push_back(Decl);
 
@@ -2127,7 +1892,7 @@ clang::NamedDecl *NameSearchContext::AddFunDecl(const CompilerType &type,
 
   QualType qual_type(ClangUtil::GetQualType(type));
 
-  clang::ASTContext *ast = lldb_ast->getASTContext();
+  clang::ASTContext &ast = lldb_ast->getASTContext();
 
   const bool isInlineSpecified = false;
   const bool hasWrittenPrototype = true;
@@ -2137,7 +1902,7 @@ clang::NamedDecl *NameSearchContext::AddFunDecl(const CompilerType &type,
 
   if (extern_c) {
     context = LinkageSpecDecl::Create(
-        *ast, context, SourceLocation(), SourceLocation(),
+        ast, context, SourceLocation(), SourceLocation(),
         clang::LinkageSpecDecl::LanguageIDs::lang_c, false);
   }
 
@@ -2149,7 +1914,7 @@ clang::NamedDecl *NameSearchContext::AddFunDecl(const CompilerType &type,
           : m_decl_name;
 
   clang::FunctionDecl *func_decl = FunctionDecl::Create(
-      *ast, context, SourceLocation(), SourceLocation(), decl_name, qual_type,
+      ast, context, SourceLocation(), SourceLocation(), decl_name, qual_type,
       nullptr, SC_Extern, isInlineSpecified, hasWrittenPrototype,
       isConstexprSpecified ? CSK_constexpr : CSK_unspecified);
 
@@ -2170,7 +1935,7 @@ clang::NamedDecl *NameSearchContext::AddFunDecl(const CompilerType &type,
       QualType arg_qual_type(func_proto_type->getParamType(ArgIndex));
 
       parm_var_decls.push_back(
-          ParmVarDecl::Create(*ast, const_cast<DeclContext *>(context),
+          ParmVarDecl::Create(ast, const_cast<DeclContext *>(context),
                               SourceLocation(), SourceLocation(), nullptr,
                               arg_qual_type, nullptr, SC_Static, nullptr));
     }
@@ -2210,9 +1975,7 @@ clang::NamedDecl *NameSearchContext::AddGenericFunDecl() {
       proto_info));
 
   return AddFunDecl(
-      CompilerType(ClangASTContext::GetASTContext(m_ast_source.m_ast_context),
-                   generic_function_type.getAsOpaquePtr()),
-      true);
+      m_ast_source.m_clang_ast_context->GetType(generic_function_type), true);
 }
 
 clang::NamedDecl *
diff --git a/lldb/source/Plugins/ExpressionParser/Clang/ClangASTSource.h b/lldb/source/Plugins/ExpressionParser/Clang/ClangASTSource.h
index 7a8bacf48a8f..3149b4266b2f 100644
--- a/lldb/source/Plugins/ExpressionParser/Clang/ClangASTSource.h
+++ b/lldb/source/Plugins/ExpressionParser/Clang/ClangASTSource.h
@@ -12,10 +12,9 @@
 #include <set>
 
 #include "lldb/Symbol/ClangASTImporter.h"
-#include "lldb/Symbol/ClangExternalASTSourceCommon.h"
 #include "lldb/Symbol/CompilerType.h"
 #include "lldb/Target/Target.h"
-#include "clang/AST/ExternalASTMerger.h"
+#include "clang/AST/ExternalASTSource.h"
 #include "clang/Basic/IdentifierTable.h"
 
 #include "llvm/ADT/SmallSet.h"
@@ -30,7 +29,7 @@ namespace lldb_private {
 /// knows the name it is looking for, but nothing else. The ExternalSemaSource
 /// class provides Decls (VarDecl, FunDecl, TypeDecl) to Clang for these
 /// names, consulting the ClangExpressionDeclMap to do the actual lookups.
-class ClangASTSource : public ClangExternalASTSourceCommon,
+class ClangASTSource : public clang::ExternalASTSource,
                        public ClangASTImporter::MapCompleter {
 public:
   /// Constructor
@@ -39,7 +38,11 @@ public:
   ///
   /// \param[in] target
   ///     A reference to the target containing debug information to use.
-  ClangASTSource(const lldb::TargetSP &target);
+  ///
+  /// \param[in] importer
+  ///     The ClangASTImporter to use.
+  ClangASTSource(const lldb::TargetSP &target,
+                 const lldb::ClangASTImporterSP &importer);
 
   /// Destructor
   ~ClangASTSource() override;
@@ -57,9 +60,7 @@ public:
   }
   void MaterializeVisibleDecls(const clang::DeclContext *DC) { return; }
 
-  void InstallASTContext(clang::ASTContext &ast_context,
-                         clang::FileManager &file_manager,
-                         bool is_shared_context = false);
+  void InstallASTContext(ClangASTContext &ast_context);
 
   //
   // APIs for ExternalASTSource
@@ -89,7 +90,7 @@ public:
   /// \param[in] DC
   ///     The DeclContext being searched.
   ///
-  /// \param[in] isKindWeWant
+  /// \param[in] IsKindWeWant
   ///     A callback function that returns true given the
   ///     DeclKinds of desired Decls, and false otherwise.
   ///
@@ -155,7 +156,7 @@ public:
   /// setHasExternalVisibleStorage() and setHasExternalLexicalStorage() that
   /// this object has something to say about undefined names.
   ///
-  /// \param[in] ASTConsumer
+  /// \param[in] Consumer
   ///     Unused.
   void StartTranslationUnit(clang::ASTConsumer *Consumer) override;
 
@@ -210,7 +211,7 @@ public:
   ///
   /// Clang AST contexts like to own their AST sources, so this is a state-
   /// free proxy object.
-  class ClangASTSourceProxy : public ClangExternalASTSourceCommon {
+  class ClangASTSourceProxy : public clang::ExternalASTSource {
   public:
     ClangASTSourceProxy(ClangASTSource &original) : m_original(original) {}
 
@@ -249,18 +250,6 @@ public:
       return m_original.StartTranslationUnit(Consumer);
     }
 
-    ClangASTMetadata *GetMetadata(const void *object) {
-      return m_original.GetMetadata(object);
-    }
-
-    void SetMetadata(const void *object, ClangASTMetadata &metadata) {
-      return m_original.SetMetadata(object, metadata);
-    }
-
-    bool HasMetadata(const void *object) {
-      return m_original.HasMetadata(object);
-    }
-
   private:
     ClangASTSource &m_original;
   };
@@ -321,13 +310,6 @@ protected:
   /// A wrapper for ClangASTContext::CopyType that sets a flag that
   /// indicates that we should not respond to queries during import.
   ///
-  /// \param[in] dest_context
-  ///     The target AST context, typically the parser's AST context.
-  ///
-  /// \param[in] source_context
-  ///     The source AST context, typically the AST context of whatever
-  ///     symbol file the type was found in.
-  ///
   /// \param[in] src_type
   ///     The source type.
   ///
@@ -341,7 +323,7 @@ public:
   /// \param[in] name
   ///     The name to be considered.
   ///
-  /// \param[in] ignore_all_dollar_nmmes
+  /// \param[in] ignore_all_dollar_names
   ///     True if $-names of all sorts should be ignored.
   ///
   /// \return
@@ -358,24 +340,6 @@ public:
   /// \return
   ///     A copy of the Decl in m_ast_context, or NULL if the copy failed.
   clang::Decl *CopyDecl(clang::Decl *src_decl);
-                         
-  /// Copies a single Type to the target of the given ExternalASTMerger.
-  ///
-  /// \param[in] src_context
-  ///     The ASTContext containing the type.
-  ///
-  /// \param[in] merger
-  ///     The merger to use.  This isn't just *m_merger_up because it might be
-  ///     the persistent AST context's merger.
-  ///
-  /// \param[in] type
-  ///     The type to copy.
-  ///
-  /// \return
-  ///     A copy of the Type in the merger's target context.
-	clang::QualType CopyTypeWithMerger(clang::ASTContext &src_context,
-                                     clang::ExternalASTMerger &merger,
-                                     clang::QualType type);
 
   /// Determined the origin of a single Decl, if it can be found.
   ///
@@ -390,16 +354,7 @@ public:
   ///
   /// \return
   ///     True if lookup succeeded; false otherwise.
-  bool ResolveDeclOrigin(const clang::Decl *decl, clang::Decl **original_decl,
-                         clang::ASTContext **original_ctx);
- 
-  /// Returns m_merger_up.  Only call this if the target is configured to use
-  /// modern lookup,
-	clang::ExternalASTMerger &GetMergerUnchecked();
- 
-  /// Returns true if there is a merger.  This only occurs if the target is
-  /// using modern lookup.
-  bool HasMerger() { return (bool)m_merger_up; }
+  ClangASTImporter::DeclOrigin GetDeclOrigin(const clang::Decl *decl);
 
 protected:
   bool FindObjCMethodDeclsWithOrigin(
@@ -411,15 +366,16 @@ protected:
   bool m_import_in_progress;
   bool m_lookups_enabled;
 
-  const lldb::TargetSP
-      m_target; ///< The target to use in finding variables and types.
-  clang::ASTContext
-      *m_ast_context; ///< The AST context requests are coming in for.
-  clang::FileManager
-      *m_file_manager; ///< The file manager paired with the AST context.
-  lldb::ClangASTImporterSP m_ast_importer_sp; ///< The target's AST importer.
-  std::unique_ptr<clang::ExternalASTMerger> m_merger_up;
-      ///< The ExternalASTMerger for this parse.
+  /// The target to use in finding variables and types.
+  const lldb::TargetSP m_target;
+  /// The AST context requests are coming in for.
+  clang::ASTContext *m_ast_context;
+  /// The ClangASTContext for m_ast_context.
+  ClangASTContext *m_clang_ast_context;
+  /// The file manager paired with the AST context.
+  clang::FileManager *m_file_manager;
+  /// The target's AST importer.
+  lldb::ClangASTImporterSP m_ast_importer_sp;
   std::set<const clang::Decl *> m_active_lexical_decls;
   std::set<const char *> m_active_lookups;
 };
@@ -432,20 +388,20 @@ protected:
 /// what name is being searched for and provides helper functions to construct
 /// Decls given appropriate type information.
 struct NameSearchContext {
-  ClangASTSource &m_ast_source; ///< The AST source making the request
-  llvm::SmallVectorImpl<clang::NamedDecl *>
-      &m_decls; ///< The list of declarations already constructed
-  ClangASTImporter::NamespaceMapSP m_namespace_map; ///< The mapping of all
-                                                    ///namespaces found for this
-                                                    ///request back to their
-                                                    ///modules
-  const clang::DeclarationName &m_decl_name; ///< The name being looked for
-  const clang::DeclContext
-      *m_decl_context; ///< The DeclContext to put declarations into
-  llvm::SmallSet<CompilerType, 5> m_function_types; ///< All the types of
-                                                    ///functions that have been
-                                                    ///reported, so we don't
-                                                    ///report conflicts
+  /// The AST source making the request.
+  ClangASTSource &m_ast_source;
+  /// The list of declarations already constructed.
+  llvm::SmallVectorImpl<clang::NamedDecl *> &m_decls;
+  /// The mapping of all namespaces found for this request back to their
+  /// modules.
+  ClangASTImporter::NamespaceMapSP m_namespace_map;
+  /// The name being looked for.
+  const clang::DeclarationName &m_decl_name;
+  /// The DeclContext to put declarations into.
+  const clang::DeclContext *m_decl_context;
+  /// All the types of functions that have been reported, so we don't
+  /// report conflicts.
+  llvm::SmallSet<CompilerType, 5> m_function_types;
 
   struct {
     bool variable : 1;
diff --git a/lldb/source/Plugins/ExpressionParser/Clang/ClangDeclVendor.cpp b/lldb/source/Plugins/ExpressionParser/Clang/ClangDeclVendor.cpp
index c59722b7b4f8..c87507a25855 100644
--- a/lldb/source/Plugins/ExpressionParser/Clang/ClangDeclVendor.cpp
+++ b/lldb/source/Plugins/ExpressionParser/Clang/ClangDeclVendor.cpp
@@ -15,16 +15,16 @@ using namespace lldb_private;
 
 uint32_t ClangDeclVendor::FindDecls(ConstString name, bool append,
                                     uint32_t max_matches,
-                                    std::vector<CompilerDecl> &decls) {
+                                    std::vector<clang::NamedDecl *> &decls) {
   if (!append)
     decls.clear();
 
-  std::vector<clang::NamedDecl *> named_decls;
-  uint32_t ret = FindDecls(name, /*append*/ false, max_matches, named_decls);
-  for (auto *named_decl : named_decls) {
-    decls.push_back(CompilerDecl(
-        ClangASTContext::GetASTContext(&named_decl->getASTContext()),
-        named_decl));
+  std::vector<CompilerDecl> compiler_decls;
+  uint32_t ret = FindDecls(name, /*append*/ false, max_matches, compiler_decls);
+  for (CompilerDecl compiler_decl : compiler_decls) {
+    clang::Decl *d = static_cast<clang::Decl *>(compiler_decl.GetOpaqueDecl());
+    clang::NamedDecl *nd = llvm::cast<clang::NamedDecl>(d);
+    decls.push_back(nd);
   }
   return ret;
 }
diff --git a/lldb/source/Plugins/ExpressionParser/Clang/ClangDeclVendor.h b/lldb/source/Plugins/ExpressionParser/Clang/ClangDeclVendor.h
index 90b715f37cba..0c888de08841 100644
--- a/lldb/source/Plugins/ExpressionParser/Clang/ClangDeclVendor.h
+++ b/lldb/source/Plugins/ExpressionParser/Clang/ClangDeclVendor.h
@@ -12,8 +12,6 @@
 #include "lldb/Core/ClangForward.h"
 #include "lldb/Symbol/DeclVendor.h"
 
-#include "clang/AST/ExternalASTMerger.h"
-
 namespace lldb_private {
 
 // A clang specialized extension to DeclVendor.
@@ -23,19 +21,10 @@ public:
 
   virtual ~ClangDeclVendor() {}
 
-  /// Interface for ExternalASTMerger. Returns an ImporterSource allowing type
-  /// completion.
-  ///
-  /// \return
-  ///     An ImporterSource for this ClangDeclVendor.
-  virtual clang::ExternalASTMerger::ImporterSource GetImporterSource() = 0;
+  using DeclVendor::FindDecls;
 
   uint32_t FindDecls(ConstString name, bool append, uint32_t max_matches,
-                     std::vector<CompilerDecl> &decls) override;
-
-  virtual uint32_t FindDecls(ConstString name, bool append,
-                             uint32_t max_matches,
-                             std::vector<clang::NamedDecl *> &decls) = 0;
+                     std::vector<clang::NamedDecl *> &decls);
 
   static bool classof(const DeclVendor *vendor) {
     return vendor->GetKind() >= eClangDeclVendor &&
diff --git a/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionDeclMap.cpp b/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionDeclMap.cpp
index f4457fc1b740..bf3023be5f60 100644
--- a/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionDeclMap.cpp
+++ b/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionDeclMap.cpp
@@ -8,7 +8,6 @@
 
 #include "ClangExpressionDeclMap.h"
 
-#include "ASTDumper.h"
 #include "ClangASTSource.h"
 #include "ClangModulesDeclVendor.h"
 #include "ClangPersistentVariables.h"
@@ -20,6 +19,7 @@
 #include "lldb/Core/ValueObjectVariable.h"
 #include "lldb/Expression/Materializer.h"
 #include "lldb/Symbol/ClangASTContext.h"
+#include "lldb/Symbol/ClangUtil.h"
 #include "lldb/Symbol/CompileUnit.h"
 #include "lldb/Symbol/CompilerDecl.h"
 #include "lldb/Symbol/CompilerDeclContext.h"
@@ -65,9 +65,10 @@ const char *g_lldb_local_vars_namespace_cstr = "$__lldb_local_vars";
 ClangExpressionDeclMap::ClangExpressionDeclMap(
     bool keep_result_in_memory,
     Materializer::PersistentVariableDelegate *result_delegate,
-    ExecutionContext &exe_ctx, ValueObject *ctx_obj)
-    : ClangASTSource(exe_ctx.GetTargetSP()), m_found_entities(),
-      m_struct_members(), m_keep_result_in_memory(keep_result_in_memory),
+    const lldb::TargetSP &target, const lldb::ClangASTImporterSP &importer,
+    ValueObject *ctx_obj)
+    : ClangASTSource(target, importer), m_found_entities(), m_struct_members(),
+      m_keep_result_in_memory(keep_result_in_memory),
       m_result_delegate(result_delegate), m_ctx_obj(ctx_obj), m_parser_vars(),
       m_struct_vars() {
   EnableStructVars();
@@ -84,8 +85,6 @@ ClangExpressionDeclMap::~ClangExpressionDeclMap() {
 
 bool ClangExpressionDeclMap::WillParse(ExecutionContext &exe_ctx,
                                        Materializer *materializer) {
-  ClangASTMetrics::ClearLocalCounters();
-
   EnableParserVars();
   m_parser_vars->m_exe_ctx = exe_ctx;
 
@@ -110,7 +109,7 @@ bool ClangExpressionDeclMap::WillParse(ExecutionContext &exe_ctx,
     m_parser_vars->m_persistent_vars = llvm::cast<ClangPersistentVariables>(
         target->GetPersistentExpressionStateForLanguage(eLanguageTypeC));
 
-    if (!target->GetScratchClangASTContext())
+    if (!ClangASTContext::GetScratch(*target))
       return false;
   }
 
@@ -127,12 +126,7 @@ void ClangExpressionDeclMap::InstallCodeGenerator(
 }
 
 void ClangExpressionDeclMap::DidParse() {
-  Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS));
-
-  if (log)
-    ClangASTMetrics::DumpCounters(log);
-
-  if (m_parser_vars) {
+  if (m_parser_vars && m_parser_vars->m_persistent_vars) {
     for (size_t entity_index = 0, num_entities = m_found_entities.GetSize();
          entity_index < num_entities; ++entity_index) {
       ExpressionVariableSP var_sp(
@@ -180,55 +174,15 @@ ClangExpressionDeclMap::TargetInfo ClangExpressionDeclMap::GetTargetInfo() {
   return ret;
 }
 
-static clang::QualType ExportAllDeclaredTypes(
-    clang::ExternalASTMerger &parent_merger, clang::ExternalASTMerger &merger,
-    clang::ASTContext &source, clang::FileManager &source_file_manager,
-    const clang::ExternalASTMerger::OriginMap &source_origin_map,
-    clang::FileID file, clang::QualType root) {
-  // Mark the source as temporary to make sure all declarations from the
-  // AST are exported. Also add the parent_merger as the merger into the
-  // source AST so that the merger can track back any declarations from
-  // the persistent ASTs we used as sources.
-  clang::ExternalASTMerger::ImporterSource importer_source(
-      source, source_file_manager, source_origin_map, /*Temporary*/ true,
-      &parent_merger);
-  merger.AddSources(importer_source);
-  clang::ASTImporter &exporter = merger.ImporterForOrigin(source);
-  llvm::Expected<clang::QualType> ret_or_error = exporter.Import(root);
-  merger.RemoveSources(importer_source);
-  if (ret_or_error) {
-    return *ret_or_error;
-  } else {
-    Log *log = lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS);
-    LLDB_LOG_ERROR(log, ret_or_error.takeError(), "Couldn't import type: {0}");
-    return clang::QualType();
-  }
-}
-
 TypeFromUser ClangExpressionDeclMap::DeportType(ClangASTContext &target,
                                                 ClangASTContext &source,
                                                 TypeFromParser parser_type) {
-  assert(&target == m_target->GetScratchClangASTContext());
+  assert(&target == ClangASTContext::GetScratch(*m_target));
   assert((TypeSystem *)&source == parser_type.GetTypeSystem());
-  assert(source.getASTContext() == m_ast_context);
+  assert(&source.getASTContext() == m_ast_context);
 
   if (m_ast_importer_sp) {
-    return TypeFromUser(m_ast_importer_sp->DeportType(
-                            target.getASTContext(), source.getASTContext(),
-                            parser_type.GetOpaqueQualType()),
-                        &target);
-  } else if (m_merger_up) {
-    clang::FileID source_file =
-        source.getASTContext()->getSourceManager().getFileID(
-            source.getASTContext()->getTranslationUnitDecl()->getLocation());
-    auto scratch_ast_context = static_cast<ClangASTContextForExpressions *>(
-        m_target->GetScratchClangASTContext());
-    clang::QualType exported_type = ExportAllDeclaredTypes(
-        *m_merger_up.get(), scratch_ast_context->GetMergerUnchecked(),
-        *source.getASTContext(), *source.getFileManager(),
-        m_merger_up->GetOrigins(), source_file,
-        clang::QualType::getFromOpaquePtr(parser_type.GetOpaqueQualType()));
-    return TypeFromUser(exported_type.getAsOpaquePtr(), &target);
+    return TypeFromUser(m_ast_importer_sp->DeportType(target, parser_type));
   } else {
     lldbassert(0 && "No mechanism for deporting a type!");
     return TypeFromUser();
@@ -255,8 +209,11 @@ bool ClangExpressionDeclMap::AddPersistentVariable(const NamedDecl *decl,
     if (target == nullptr)
       return false;
 
-    TypeFromUser user_type =
-        DeportType(*target->GetScratchClangASTContext(), *ast, parser_type);
+    auto *clang_ast_context = ClangASTContext::GetScratch(*target);
+    if (!clang_ast_context)
+      return false;
+
+    TypeFromUser user_type = DeportType(*clang_ast_context, *ast, parser_type);
 
     uint32_t offset = m_parser_vars->m_materializer->AddResultVariable(
         user_type, is_lvalue, m_keep_result_in_memory, m_result_delegate, err);
@@ -291,7 +248,9 @@ bool ClangExpressionDeclMap::AddPersistentVariable(const NamedDecl *decl,
   if (target == nullptr)
     return false;
 
-  ClangASTContext *context(target->GetScratchClangASTContext());
+  ClangASTContext *context = ClangASTContext::GetScratch(*target);
+  if (!context)
+    return false;
 
   TypeFromUser user_type = DeportType(*context, *ast, parser_type);
 
@@ -303,6 +262,9 @@ bool ClangExpressionDeclMap::AddPersistentVariable(const NamedDecl *decl,
   if (!m_parser_vars->m_target_info.IsValid())
     return false;
 
+  if (!m_parser_vars->m_persistent_vars)
+    return false;
+
   ClangExpressionVariable *var = llvm::cast<ClangExpressionVariable>(
       m_parser_vars->m_persistent_vars
           ->CreatePersistentVariable(
@@ -368,7 +330,7 @@ bool ClangExpressionDeclMap::AddValueToStruct(const NamedDecl *decl,
   ClangExpressionVariable *var(ClangExpressionVariable::FindVariableInList(
       m_found_entities, decl, GetParserID()));
 
-  if (!var) {
+  if (!var && m_parser_vars->m_persistent_vars) {
     var = ClangExpressionVariable::FindVariableInList(
         *m_parser_vars->m_persistent_vars, decl, GetParserID());
     is_persistent_variable = true;
@@ -638,7 +600,7 @@ addr_t ClangExpressionDeclMap::GetSymbolAddress(ConstString name,
 
 lldb::VariableSP ClangExpressionDeclMap::FindGlobalVariable(
     Target &target, ModuleSP &module, ConstString name,
-    CompilerDeclContext *namespace_decl, TypeFromUser *type) {
+    CompilerDeclContext *namespace_decl) {
   VariableList vars;
 
   if (module && namespace_decl)
@@ -646,21 +608,9 @@ lldb::VariableSP ClangExpressionDeclMap::FindGlobalVariable(
   else
     target.GetImages().FindGlobalVariables(name, -1, vars);
 
-  if (vars.GetSize()) {
-    if (type) {
-      for (size_t i = 0; i < vars.GetSize(); ++i) {
-        VariableSP var_sp = vars.GetVariableAtIndex(i);
-
-        if (ClangASTContext::AreTypesSame(
-                *type, var_sp->GetType()->GetFullCompilerType()))
-          return var_sp;
-      }
-    } else {
-      return vars.GetVariableAtIndex(0);
-    }
-  }
-
-  return VariableSP();
+  if (vars.GetSize() == 0)
+    return VariableSP();
+  return vars.GetVariableAtIndex(0);
 }
 
 ClangASTContext *ClangExpressionDeclMap::GetClangASTContext() {
@@ -687,8 +637,6 @@ void ClangExpressionDeclMap::FindExternalVisibleDecls(
     NameSearchContext &context) {
   assert(m_ast_context);
 
-  ClangASTMetrics::RegisterVisibleQuery();
-
   const ConstString name(context.m_decl_name.getAsString().c_str());
 
   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS));
@@ -727,9 +675,9 @@ void ClangExpressionDeclMap::FindExternalVisibleDecls(
           dyn_cast<NamespaceDecl>(context.m_decl_context)) {
     if (namespace_context->getName().str() ==
         std::string(g_lldb_local_vars_namespace_cstr)) {
-      CompilerDeclContext compiler_decl_ctx(
-          GetClangASTContext(), const_cast<void *>(static_cast<const void *>(
-                                    context.m_decl_context)));
+      CompilerDeclContext compiler_decl_ctx =
+          m_clang_ast_context->CreateDeclContext(
+              const_cast<clang::DeclContext *>(context.m_decl_context));
       FindExternalVisibleDecls(context, lldb::ModuleSP(), compiler_decl_ctx,
                                current_id);
       return;
@@ -771,743 +719,760 @@ void ClangExpressionDeclMap::FindExternalVisibleDecls(
   ClangASTSource::FindExternalVisibleDecls(context);
 }
 
-void ClangExpressionDeclMap::FindExternalVisibleDecls(
-    NameSearchContext &context, lldb::ModuleSP module_sp,
-    CompilerDeclContext &namespace_decl, unsigned int current_id) {
-  assert(m_ast_context);
+void ClangExpressionDeclMap::MaybeRegisterFunctionBody(
+    FunctionDecl *copied_function_decl) {
+  if (copied_function_decl->getBody() && m_parser_vars->m_code_gen) {
+    clang::DeclGroupRef decl_group_ref(copied_function_decl);
+    m_parser_vars->m_code_gen->HandleTopLevelDecl(decl_group_ref);
+  }
+}
 
-  std::function<void(clang::FunctionDecl *)> MaybeRegisterFunctionBody =
-      [this](clang::FunctionDecl *copied_function_decl) {
-        if (copied_function_decl->getBody() && m_parser_vars->m_code_gen) {
-          DeclGroupRef decl_group_ref(copied_function_decl);
-          m_parser_vars->m_code_gen->HandleTopLevelDecl(decl_group_ref);
-        }
-      };
+clang::NamedDecl *ClangExpressionDeclMap::GetPersistentDecl(ConstString name) {
+  if (!m_parser_vars)
+    return nullptr;
+  Target *target = m_parser_vars->m_exe_ctx.GetTargetPtr();
+  if (!target)
+    return nullptr;
+
+  ClangASTContext::GetScratch(*target);
+
+  if (!m_parser_vars->m_persistent_vars)
+    return nullptr;
+  return m_parser_vars->m_persistent_vars->GetPersistentDecl(name);
+}
 
+void ClangExpressionDeclMap::SearchPersistenDecls(NameSearchContext &context,
+                                                  const ConstString name,
+                                                  unsigned int current_id) {
   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS));
 
-  SymbolContextList sc_list;
+  NamedDecl *persistent_decl = GetPersistentDecl(name);
 
-  const ConstString name(context.m_decl_name.getAsString().c_str());
-  if (IgnoreName(name, false))
+  if (!persistent_decl)
     return;
 
-  // Only look for functions by name out in our symbols if the function doesn't
-  // start with our phony prefix of '$'
-  Target *target = m_parser_vars->m_exe_ctx.GetTargetPtr();
+  Decl *parser_persistent_decl = CopyDecl(persistent_decl);
+
+  if (!parser_persistent_decl)
+    return;
+
+  NamedDecl *parser_named_decl = dyn_cast<NamedDecl>(parser_persistent_decl);
+
+  if (!parser_named_decl)
+    return;
+
+  if (clang::FunctionDecl *parser_function_decl =
+          llvm::dyn_cast<clang::FunctionDecl>(parser_named_decl)) {
+    MaybeRegisterFunctionBody(parser_function_decl);
+  }
+
+  LLDB_LOGF(log, "  CEDM::FEVD[%u] Found persistent decl %s", current_id,
+            name.GetCString());
+
+  context.AddNamedDecl(parser_named_decl);
+}
+
+void ClangExpressionDeclMap::LookUpLldbClass(NameSearchContext &context,
+                                             unsigned int current_id) {
+  Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS));
+
   StackFrame *frame = m_parser_vars->m_exe_ctx.GetFramePtr();
   SymbolContext sym_ctx;
   if (frame != nullptr)
     sym_ctx = frame->GetSymbolContext(lldb::eSymbolContextFunction |
                                       lldb::eSymbolContextBlock);
 
-  // Try the persistent decls, which take precedence over all else.
-  if (!namespace_decl) {
-    do {
-      if (!target)
-        break;
+  if (m_ctx_obj) {
+    Status status;
+    lldb::ValueObjectSP ctx_obj_ptr = m_ctx_obj->AddressOf(status);
+    if (!ctx_obj_ptr || status.Fail())
+      return;
 
-      ClangASTContext *scratch_clang_ast_context =
-          target->GetScratchClangASTContext();
+    AddThisType(context, TypeFromUser(m_ctx_obj->GetCompilerType()),
+                current_id);
 
-      if (!scratch_clang_ast_context)
-        break;
+    m_struct_vars->m_object_pointer_type =
+        TypeFromUser(ctx_obj_ptr->GetCompilerType());
 
-      ASTContext *scratch_ast_context =
-          scratch_clang_ast_context->getASTContext();
+    return;
+  }
 
-      if (!scratch_ast_context)
-        break;
+  // Clang is looking for the type of "this"
 
-      NamedDecl *persistent_decl =
-          m_parser_vars->m_persistent_vars->GetPersistentDecl(name);
+  if (frame == nullptr)
+    return;
 
-      if (!persistent_decl)
-        break;
+  // Find the block that defines the function represented by "sym_ctx"
+  Block *function_block = sym_ctx.GetFunctionBlock();
 
-      Decl *parser_persistent_decl = CopyDecl(persistent_decl);
+  if (!function_block)
+    return;
 
-      if (!parser_persistent_decl)
-        break;
+  CompilerDeclContext function_decl_ctx = function_block->GetDeclContext();
 
-      NamedDecl *parser_named_decl =
-          dyn_cast<NamedDecl>(parser_persistent_decl);
+  if (!function_decl_ctx)
+    return;
 
-      if (!parser_named_decl)
-        break;
+  clang::CXXMethodDecl *method_decl =
+      ClangASTContext::DeclContextGetAsCXXMethodDecl(function_decl_ctx);
 
-      if (clang::FunctionDecl *parser_function_decl =
-              llvm::dyn_cast<clang::FunctionDecl>(parser_named_decl)) {
-        MaybeRegisterFunctionBody(parser_function_decl);
-      }
+  if (method_decl) {
+    clang::CXXRecordDecl *class_decl = method_decl->getParent();
 
-      LLDB_LOGF(log, "  CEDM::FEVD[%u] Found persistent decl %s", current_id,
-                name.GetCString());
+    QualType class_qual_type(class_decl->getTypeForDecl(), 0);
 
-      context.AddNamedDecl(parser_named_decl);
-    } while (false);
-  }
+    TypeFromUser class_user_type(class_qual_type.getAsOpaquePtr(),
+                                 function_decl_ctx.GetTypeSystem());
 
-  if (name.GetCString()[0] == '$' && !namespace_decl) {
-    static ConstString g_lldb_class_name("$__lldb_class");
+    LLDB_LOG(log, "  CEDM::FEVD[{0}] Adding type for $__lldb_class: {1}",
+             current_id, class_qual_type.getAsString());
 
-    if (name == g_lldb_class_name) {
-      if (m_ctx_obj) {
-        Status status;
-        lldb::ValueObjectSP ctx_obj_ptr = m_ctx_obj->AddressOf(status);
-        if (!ctx_obj_ptr || status.Fail())
-          return;
+    AddThisType(context, class_user_type, current_id);
 
-        AddThisType(context, TypeFromUser(m_ctx_obj->GetCompilerType()),
-                    current_id);
+    if (method_decl->isInstance()) {
+      // self is a pointer to the object
 
-        m_struct_vars->m_object_pointer_type =
-            TypeFromUser(ctx_obj_ptr->GetCompilerType());
+      QualType class_pointer_type =
+          method_decl->getASTContext().getPointerType(class_qual_type);
 
-        return;
-      }
+      TypeFromUser self_user_type(class_pointer_type.getAsOpaquePtr(),
+                                  function_decl_ctx.GetTypeSystem());
 
-      // Clang is looking for the type of "this"
+      m_struct_vars->m_object_pointer_type = self_user_type;
+    }
+    return;
+  }
 
-      if (frame == nullptr)
-        return;
+  // This branch will get hit if we are executing code in the context of
+  // a function that claims to have an object pointer (through
+  // DW_AT_object_pointer?) but is not formally a method of the class.
+  // In that case, just look up the "this" variable in the current scope
+  // and use its type.
+  // FIXME: This code is formally correct, but clang doesn't currently
+  // emit DW_AT_object_pointer
+  // for C++ so it hasn't actually been tested.
 
-      // Find the block that defines the function represented by "sym_ctx"
-      Block *function_block = sym_ctx.GetFunctionBlock();
+  VariableList *vars = frame->GetVariableList(false);
 
-      if (!function_block)
-        return;
+  lldb::VariableSP this_var = vars->FindVariable(ConstString("this"));
 
-      CompilerDeclContext function_decl_ctx = function_block->GetDeclContext();
+  if (this_var && this_var->IsInScope(frame) &&
+      this_var->LocationIsValidForFrame(frame)) {
+    Type *this_type = this_var->GetType();
 
-      if (!function_decl_ctx)
-        return;
+    if (!this_type)
+      return;
 
-      clang::CXXMethodDecl *method_decl =
-          ClangASTContext::DeclContextGetAsCXXMethodDecl(function_decl_ctx);
+    TypeFromUser pointee_type =
+        this_type->GetForwardCompilerType().GetPointeeType();
 
-      if (method_decl) {
-        clang::CXXRecordDecl *class_decl = method_decl->getParent();
+    LLDB_LOG(log, "  FEVD[{0}] Adding type for $__lldb_class: {1}", current_id,
+             ClangUtil::GetQualType(pointee_type).getAsString());
 
-        QualType class_qual_type(class_decl->getTypeForDecl(), 0);
+    AddThisType(context, pointee_type, current_id);
+    TypeFromUser this_user_type(this_type->GetFullCompilerType());
+    m_struct_vars->m_object_pointer_type = this_user_type;
+  }
+}
 
-        TypeFromUser class_user_type(
-            class_qual_type.getAsOpaquePtr(),
-            ClangASTContext::GetASTContext(&class_decl->getASTContext()));
+void ClangExpressionDeclMap::LookUpLldbObjCClass(NameSearchContext &context,
+                                                 unsigned int current_id) {
+  Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS));
 
-        if (log) {
-          ASTDumper ast_dumper(class_qual_type);
-          LLDB_LOGF(log, "  CEDM::FEVD[%u] Adding type for $__lldb_class: %s",
-                    current_id, ast_dumper.GetCString());
-        }
+  StackFrame *frame = m_parser_vars->m_exe_ctx.GetFramePtr();
 
-        AddThisType(context, class_user_type, current_id);
+  if (m_ctx_obj) {
+    Status status;
+    lldb::ValueObjectSP ctx_obj_ptr = m_ctx_obj->AddressOf(status);
+    if (!ctx_obj_ptr || status.Fail())
+      return;
 
-        if (method_decl->isInstance()) {
-          // self is a pointer to the object
+    AddOneType(context, TypeFromUser(m_ctx_obj->GetCompilerType()), current_id);
 
-          QualType class_pointer_type =
-              method_decl->getASTContext().getPointerType(class_qual_type);
+    m_struct_vars->m_object_pointer_type =
+        TypeFromUser(ctx_obj_ptr->GetCompilerType());
 
-          TypeFromUser self_user_type(
-              class_pointer_type.getAsOpaquePtr(),
-              ClangASTContext::GetASTContext(&method_decl->getASTContext()));
+    return;
+  }
 
-          m_struct_vars->m_object_pointer_type = self_user_type;
-        }
-      } else {
-        // This branch will get hit if we are executing code in the context of
-        // a function that claims to have an object pointer (through
-        // DW_AT_object_pointer?) but is not formally a method of the class.
-        // In that case, just look up the "this" variable in the current scope
-        // and use its type.
-        // FIXME: This code is formally correct, but clang doesn't currently
-        // emit DW_AT_object_pointer
-        // for C++ so it hasn't actually been tested.
+  // Clang is looking for the type of "*self"
+
+  if (!frame)
+    return;
 
-        VariableList *vars = frame->GetVariableList(false);
+  SymbolContext sym_ctx = frame->GetSymbolContext(lldb::eSymbolContextFunction |
+                                                  lldb::eSymbolContextBlock);
 
-        lldb::VariableSP this_var = vars->FindVariable(ConstString("this"));
+  // Find the block that defines the function represented by "sym_ctx"
+  Block *function_block = sym_ctx.GetFunctionBlock();
 
-        if (this_var && this_var->IsInScope(frame) &&
-            this_var->LocationIsValidForFrame(frame)) {
-          Type *this_type = this_var->GetType();
+  if (!function_block)
+    return;
 
-          if (!this_type)
-            return;
+  CompilerDeclContext function_decl_ctx = function_block->GetDeclContext();
 
-          TypeFromUser pointee_type =
-              this_type->GetForwardCompilerType().GetPointeeType();
+  if (!function_decl_ctx)
+    return;
 
-          if (pointee_type.IsValid()) {
-            if (log) {
-              ASTDumper ast_dumper(pointee_type);
-              LLDB_LOGF(log, "  FEVD[%u] Adding type for $__lldb_class: %s",
-                        current_id, ast_dumper.GetCString());
-            }
+  clang::ObjCMethodDecl *method_decl =
+      ClangASTContext::DeclContextGetAsObjCMethodDecl(function_decl_ctx);
 
-            AddThisType(context, pointee_type, current_id);
-            TypeFromUser this_user_type(this_type->GetFullCompilerType());
-            m_struct_vars->m_object_pointer_type = this_user_type;
-            return;
-          }
-        }
-      }
+  if (method_decl) {
+    ObjCInterfaceDecl *self_interface = method_decl->getClassInterface();
 
+    if (!self_interface)
       return;
-    }
 
-    static ConstString g_lldb_objc_class_name("$__lldb_objc_class");
-    if (name == g_lldb_objc_class_name) {
-      if (m_ctx_obj) {
-        Status status;
-        lldb::ValueObjectSP ctx_obj_ptr = m_ctx_obj->AddressOf(status);
-        if (!ctx_obj_ptr || status.Fail())
-          return;
+    const clang::Type *interface_type = self_interface->getTypeForDecl();
 
-        AddOneType(context, TypeFromUser(m_ctx_obj->GetCompilerType()),
-                   current_id);
+    if (!interface_type)
+      return; // This is unlikely, but we have seen crashes where this
+              // occurred
 
-        m_struct_vars->m_object_pointer_type =
-            TypeFromUser(ctx_obj_ptr->GetCompilerType());
+    TypeFromUser class_user_type(QualType(interface_type, 0).getAsOpaquePtr(),
+                                 function_decl_ctx.GetTypeSystem());
 
-        return;
-      }
+    LLDB_LOG(log, "  FEVD[{0}] Adding type for $__lldb_objc_class: {1}",
+             current_id, ClangUtil::ToString(interface_type));
 
-      // Clang is looking for the type of "*self"
+    AddOneType(context, class_user_type, current_id);
 
-      if (!frame)
-        return;
+    if (method_decl->isInstanceMethod()) {
+      // self is a pointer to the object
 
-      SymbolContext sym_ctx = frame->GetSymbolContext(
-          lldb::eSymbolContextFunction | lldb::eSymbolContextBlock);
+      QualType class_pointer_type =
+          method_decl->getASTContext().getObjCObjectPointerType(
+              QualType(interface_type, 0));
 
-      // Find the block that defines the function represented by "sym_ctx"
-      Block *function_block = sym_ctx.GetFunctionBlock();
+      TypeFromUser self_user_type(class_pointer_type.getAsOpaquePtr(),
+                                  function_decl_ctx.GetTypeSystem());
 
-      if (!function_block)
-        return;
+      m_struct_vars->m_object_pointer_type = self_user_type;
+    } else {
+      // self is a Class pointer
+      QualType class_type = method_decl->getASTContext().getObjCClassType();
 
-      CompilerDeclContext function_decl_ctx = function_block->GetDeclContext();
+      TypeFromUser self_user_type(class_type.getAsOpaquePtr(),
+                                  function_decl_ctx.GetTypeSystem());
 
-      if (!function_decl_ctx)
-        return;
+      m_struct_vars->m_object_pointer_type = self_user_type;
+    }
 
-      clang::ObjCMethodDecl *method_decl =
-          ClangASTContext::DeclContextGetAsObjCMethodDecl(function_decl_ctx);
+    return;
+  }
+  // This branch will get hit if we are executing code in the context of
+  // a function that claims to have an object pointer (through
+  // DW_AT_object_pointer?) but is not formally a method of the class.
+  // In that case, just look up the "self" variable in the current scope
+  // and use its type.
 
-      if (method_decl) {
-        ObjCInterfaceDecl *self_interface = method_decl->getClassInterface();
+  VariableList *vars = frame->GetVariableList(false);
 
-        if (!self_interface)
-          return;
+  lldb::VariableSP self_var = vars->FindVariable(ConstString("self"));
 
-        const clang::Type *interface_type = self_interface->getTypeForDecl();
+  if (!self_var)
+    return;
+  if (!self_var->IsInScope(frame))
+    return;
+  if (!self_var->LocationIsValidForFrame(frame))
+    return;
 
-        if (!interface_type)
-          return; // This is unlikely, but we have seen crashes where this
-                  // occurred
+  Type *self_type = self_var->GetType();
 
-        TypeFromUser class_user_type(
-            QualType(interface_type, 0).getAsOpaquePtr(),
-            ClangASTContext::GetASTContext(&method_decl->getASTContext()));
+  if (!self_type)
+    return;
 
-        if (log) {
-          ASTDumper ast_dumper(interface_type);
-          LLDB_LOGF(log, "  FEVD[%u] Adding type for $__lldb_objc_class: %s",
-                    current_id, ast_dumper.GetCString());
-        }
+  CompilerType self_clang_type = self_type->GetFullCompilerType();
 
-        AddOneType(context, class_user_type, current_id);
+  if (ClangASTContext::IsObjCClassType(self_clang_type)) {
+    return;
+  }
+  if (!ClangASTContext::IsObjCObjectPointerType(self_clang_type))
+    return;
+  self_clang_type = self_clang_type.GetPointeeType();
 
-        if (method_decl->isInstanceMethod()) {
-          // self is a pointer to the object
+  if (!self_clang_type)
+    return;
 
-          QualType class_pointer_type =
-              method_decl->getASTContext().getObjCObjectPointerType(
-                  QualType(interface_type, 0));
+  LLDB_LOG(log, "  FEVD[{0}] Adding type for $__lldb_objc_class: {1}",
+           current_id, ClangUtil::ToString(self_type->GetFullCompilerType()));
 
-          TypeFromUser self_user_type(
-              class_pointer_type.getAsOpaquePtr(),
-              ClangASTContext::GetASTContext(&method_decl->getASTContext()));
+  TypeFromUser class_user_type(self_clang_type);
 
-          m_struct_vars->m_object_pointer_type = self_user_type;
-        } else {
-          // self is a Class pointer
-          QualType class_type = method_decl->getASTContext().getObjCClassType();
+  AddOneType(context, class_user_type, current_id);
 
-          TypeFromUser self_user_type(
-              class_type.getAsOpaquePtr(),
-              ClangASTContext::GetASTContext(&method_decl->getASTContext()));
+  TypeFromUser self_user_type(self_type->GetFullCompilerType());
 
-          m_struct_vars->m_object_pointer_type = self_user_type;
-        }
+  m_struct_vars->m_object_pointer_type = self_user_type;
+}
 
-        return;
-      } else {
-        // This branch will get hit if we are executing code in the context of
-        // a function that claims to have an object pointer (through
-        // DW_AT_object_pointer?) but is not formally a method of the class.
-        // In that case, just look up the "self" variable in the current scope
-        // and use its type.
+void ClangExpressionDeclMap::LookupLocalVarNamespace(
+    SymbolContext &sym_ctx, NameSearchContext &name_context) {
+  if (sym_ctx.block == nullptr)
+    return;
 
-        VariableList *vars = frame->GetVariableList(false);
+  CompilerDeclContext frame_decl_context = sym_ctx.block->GetDeclContext();
+  if (!frame_decl_context)
+    return;
 
-        lldb::VariableSP self_var = vars->FindVariable(ConstString("self"));
+  ClangASTContext *frame_ast = llvm::dyn_cast_or_null<ClangASTContext>(
+      frame_decl_context.GetTypeSystem());
+  if (!frame_ast)
+    return;
 
-        if (self_var && self_var->IsInScope(frame) &&
-            self_var->LocationIsValidForFrame(frame)) {
-          Type *self_type = self_var->GetType();
+  clang::NamespaceDecl *namespace_decl =
+      m_clang_ast_context->GetUniqueNamespaceDeclaration(
+          g_lldb_local_vars_namespace_cstr, nullptr);
+  if (!namespace_decl)
+    return;
 
-          if (!self_type)
-            return;
+  name_context.AddNamedDecl(namespace_decl);
+  clang::DeclContext *ctxt = clang::Decl::castToDeclContext(namespace_decl);
+  ctxt->setHasExternalVisibleStorage(true);
+  name_context.m_found.local_vars_nsp = true;
+}
 
-          CompilerType self_clang_type = self_type->GetFullCompilerType();
+void ClangExpressionDeclMap::LookupInModulesDeclVendor(
+    NameSearchContext &context, ConstString name, unsigned current_id) {
+  Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS));
 
-          if (ClangASTContext::IsObjCClassType(self_clang_type)) {
-            return;
-          } else if (ClangASTContext::IsObjCObjectPointerType(
-                         self_clang_type)) {
-            self_clang_type = self_clang_type.GetPointeeType();
+  if (!m_target)
+    return;
 
-            if (!self_clang_type)
-              return;
+  auto *modules_decl_vendor = m_target->GetClangModulesDeclVendor();
+  if (!modules_decl_vendor)
+    return;
 
-            if (log) {
-              ASTDumper ast_dumper(self_type->GetFullCompilerType());
-              LLDB_LOGF(log,
-                        "  FEVD[%u] Adding type for $__lldb_objc_class: %s",
-                        current_id, ast_dumper.GetCString());
-            }
+  bool append = false;
+  uint32_t max_matches = 1;
+  std::vector<clang::NamedDecl *> decls;
 
-            TypeFromUser class_user_type(self_clang_type);
+  if (!modules_decl_vendor->FindDecls(name, append, max_matches, decls))
+    return;
 
-            AddOneType(context, class_user_type, current_id);
+  assert(!decls.empty() && "FindDecls returned true but no decls?");
+  clang::NamedDecl *const decl_from_modules = decls[0];
 
-            TypeFromUser self_user_type(self_type->GetFullCompilerType());
+  LLDB_LOG(log,
+           "  CAS::FEVD[{0}] Matching decl found for "
+           "\"{1}\" in the modules",
+           current_id, name);
 
-            m_struct_vars->m_object_pointer_type = self_user_type;
-            return;
-          }
-        }
-      }
+  clang::Decl *copied_decl = CopyDecl(decl_from_modules);
+  if (!copied_decl) {
+    LLDB_LOG(log,
+             "  CAS::FEVD[{0}] - Couldn't export a "
+             "declaration from the modules",
+             current_id);
+    return;
+  }
 
-      return;
-    }
+  if (auto copied_function = dyn_cast<clang::FunctionDecl>(copied_decl)) {
+    MaybeRegisterFunctionBody(copied_function);
 
-    if (name == ConstString(g_lldb_local_vars_namespace_cstr)) {
-      CompilerDeclContext frame_decl_context =
-          sym_ctx.block != nullptr ? sym_ctx.block->GetDeclContext()
-                                   : CompilerDeclContext();
-
-      if (frame_decl_context) {
-        ClangASTContext *ast = llvm::dyn_cast_or_null<ClangASTContext>(
-            frame_decl_context.GetTypeSystem());
-
-        if (ast) {
-          clang::NamespaceDecl *namespace_decl =
-              ClangASTContext::GetUniqueNamespaceDeclaration(
-                  m_ast_context, name.GetCString(), nullptr);
-          if (namespace_decl) {
-            context.AddNamedDecl(namespace_decl);
-            clang::DeclContext *clang_decl_ctx =
-                clang::Decl::castToDeclContext(namespace_decl);
-            clang_decl_ctx->setHasExternalVisibleStorage(true);
-            context.m_found.local_vars_nsp = true;
-          }
-        }
-      }
+    context.AddNamedDecl(copied_function);
 
-      return;
-    }
+    context.m_found.function_with_type_info = true;
+    context.m_found.function = true;
+  } else if (auto copied_var = dyn_cast<clang::VarDecl>(copied_decl)) {
+    context.AddNamedDecl(copied_var);
+    context.m_found.variable = true;
+  }
+}
 
-    // any other $__lldb names should be weeded out now
-    if (name.GetStringRef().startswith("$__lldb"))
-      return;
+bool ClangExpressionDeclMap::LookupLocalVariable(
+    NameSearchContext &context, ConstString name, unsigned current_id,
+    SymbolContext &sym_ctx, CompilerDeclContext &namespace_decl) {
+  if (sym_ctx.block == nullptr)
+    return false;
 
-    ExpressionVariableSP pvar_sp(
-        m_parser_vars->m_persistent_vars->GetVariable(name));
+  CompilerDeclContext decl_context = sym_ctx.block->GetDeclContext();
+  if (!decl_context)
+    return false;
 
-    if (pvar_sp) {
-      AddOneVariable(context, pvar_sp, current_id);
-      return;
+  // Make sure that the variables are parsed so that we have the
+  // declarations.
+  StackFrame *frame = m_parser_vars->m_exe_ctx.GetFramePtr();
+  VariableListSP vars = frame->GetInScopeVariableList(true);
+  for (size_t i = 0; i < vars->GetSize(); i++)
+    vars->GetVariableAtIndex(i)->GetDecl();
+
+  // Search for declarations matching the name. Do not include imported
+  // decls in the search if we are looking for decls in the artificial
+  // namespace $__lldb_local_vars.
+  std::vector<CompilerDecl> found_decls =
+      decl_context.FindDeclByName(name, namespace_decl.IsValid());
+
+  VariableSP var;
+  bool variable_found = false;
+  for (CompilerDecl decl : found_decls) {
+    for (size_t vi = 0, ve = vars->GetSize(); vi != ve; ++vi) {
+      VariableSP candidate_var = vars->GetVariableAtIndex(vi);
+      if (candidate_var->GetDecl() == decl) {
+        var = candidate_var;
+        break;
+      }
     }
 
-    const char *reg_name(&name.GetCString()[1]);
+    if (var && !variable_found) {
+      variable_found = true;
+      ValueObjectSP valobj = ValueObjectVariable::Create(frame, var);
+      AddOneVariable(context, var, valobj, current_id);
+      context.m_found.variable = true;
+    }
+  }
+  return variable_found;
+}
 
-    if (m_parser_vars->m_exe_ctx.GetRegisterContext()) {
-      const RegisterInfo *reg_info(
-          m_parser_vars->m_exe_ctx.GetRegisterContext()->GetRegisterInfoByName(
-              reg_name));
+/// Structure to hold the info needed when comparing function
+/// declarations.
+namespace {
+struct FuncDeclInfo {
+  ConstString m_name;
+  CompilerType m_copied_type;
+  uint32_t m_decl_lvl;
+  SymbolContext m_sym_ctx;
+};
+} // namespace
+
+SymbolContextList ClangExpressionDeclMap::SearchFunctionsInSymbolContexts(
+    const SymbolContextList &sc_list,
+    const CompilerDeclContext &frame_decl_context) {
+  // First, symplify things by looping through the symbol contexts to
+  // remove unwanted functions and separate out the functions we want to
+  // compare and prune into a separate list. Cache the info needed about
+  // the function declarations in a vector for efficiency.
+  uint32_t num_indices = sc_list.GetSize();
+  SymbolContextList sc_sym_list;
+  std::vector<FuncDeclInfo> decl_infos;
+  decl_infos.reserve(num_indices);
+  clang::DeclContext *frame_decl_ctx =
+      (clang::DeclContext *)frame_decl_context.GetOpaqueDeclContext();
+  ClangASTContext *ast = llvm::dyn_cast_or_null<ClangASTContext>(
+      frame_decl_context.GetTypeSystem());
 
-      if (reg_info) {
-        LLDB_LOGF(log, "  CEDM::FEVD[%u] Found register %s", current_id,
-                  reg_info->name);
+  for (uint32_t index = 0; index < num_indices; ++index) {
+    FuncDeclInfo fdi;
+    SymbolContext sym_ctx;
+    sc_list.GetContextAtIndex(index, sym_ctx);
 
-        AddOneRegister(context, reg_info, current_id);
-      }
+    // We don't know enough about symbols to compare them, but we should
+    // keep them in the list.
+    Function *function = sym_ctx.function;
+    if (!function) {
+      sc_sym_list.Append(sym_ctx);
+      continue;
+    }
+    // Filter out functions without declaration contexts, as well as
+    // class/instance methods, since they'll be skipped in the code that
+    // follows anyway.
+    CompilerDeclContext func_decl_context = function->GetDeclContext();
+    if (!func_decl_context ||
+        func_decl_context.IsClassMethod(nullptr, nullptr, nullptr))
+      continue;
+    // We can only prune functions for which we can copy the type.
+    CompilerType func_clang_type = function->GetType()->GetFullCompilerType();
+    CompilerType copied_func_type = GuardedCopyType(func_clang_type);
+    if (!copied_func_type) {
+      sc_sym_list.Append(sym_ctx);
+      continue;
     }
-  } else {
-    ValueObjectSP valobj;
-    VariableSP var;
-
-    bool local_var_lookup =
-        !namespace_decl || (namespace_decl.GetName() ==
-                            ConstString(g_lldb_local_vars_namespace_cstr));
-    if (frame && local_var_lookup) {
-      CompilerDeclContext compiler_decl_context =
-          sym_ctx.block != nullptr ? sym_ctx.block->GetDeclContext()
-                                   : CompilerDeclContext();
-
-      if (compiler_decl_context) {
-        // Make sure that the variables are parsed so that we have the
-        // declarations.
-        VariableListSP vars = frame->GetInScopeVariableList(true);
-        for (size_t i = 0; i < vars->GetSize(); i++)
-          vars->GetVariableAtIndex(i)->GetDecl();
-
-        // Search for declarations matching the name. Do not include imported
-        // decls in the search if we are looking for decls in the artificial
-        // namespace $__lldb_local_vars.
-        std::vector<CompilerDecl> found_decls =
-            compiler_decl_context.FindDeclByName(name,
-                                                 namespace_decl.IsValid());
-
-        bool variable_found = false;
-        for (CompilerDecl decl : found_decls) {
-          for (size_t vi = 0, ve = vars->GetSize(); vi != ve; ++vi) {
-            VariableSP candidate_var = vars->GetVariableAtIndex(vi);
-            if (candidate_var->GetDecl() == decl) {
-              var = candidate_var;
-              break;
-            }
-          }
 
-          if (var && !variable_found) {
-            variable_found = true;
-            valobj = ValueObjectVariable::Create(frame, var);
-            AddOneVariable(context, var, valobj, current_id);
-            context.m_found.variable = true;
-          }
-        }
-        if (variable_found)
-          return;
-      }
+    fdi.m_sym_ctx = sym_ctx;
+    fdi.m_name = function->GetName();
+    fdi.m_copied_type = copied_func_type;
+    fdi.m_decl_lvl = LLDB_INVALID_DECL_LEVEL;
+    if (fdi.m_copied_type && func_decl_context) {
+      // Call CountDeclLevels to get the number of parent scopes we have
+      // to look through before we find the function declaration. When
+      // comparing functions of the same type, the one with a lower count
+      // will be closer to us in the lookup scope and shadows the other.
+      clang::DeclContext *func_decl_ctx =
+          (clang::DeclContext *)func_decl_context.GetOpaqueDeclContext();
+      fdi.m_decl_lvl = ast->CountDeclLevels(frame_decl_ctx, func_decl_ctx,
+                                            &fdi.m_name, &fdi.m_copied_type);
     }
-    if (target) {
-      var = FindGlobalVariable(*target, module_sp, name, &namespace_decl,
-                               nullptr);
+    decl_infos.emplace_back(fdi);
+  }
 
-      if (var) {
-        valobj = ValueObjectVariable::Create(target, var);
-        AddOneVariable(context, var, valobj, current_id);
-        context.m_found.variable = true;
-        return;
-      }
+  // Loop through the functions in our cache looking for matching types,
+  // then compare their scope levels to see which is closer.
+  std::multimap<CompilerType, const FuncDeclInfo *> matches;
+  for (const FuncDeclInfo &fdi : decl_infos) {
+    const CompilerType t = fdi.m_copied_type;
+    auto q = matches.find(t);
+    if (q != matches.end()) {
+      if (q->second->m_decl_lvl > fdi.m_decl_lvl)
+        // This function is closer; remove the old set.
+        matches.erase(t);
+      else if (q->second->m_decl_lvl < fdi.m_decl_lvl)
+        // The functions in our set are closer - skip this one.
+        continue;
     }
+    matches.insert(std::make_pair(t, &fdi));
+  }
 
-    std::vector<clang::NamedDecl *> decls_from_modules;
+  // Loop through our matches and add their symbol contexts to our list.
+  SymbolContextList sc_func_list;
+  for (const auto &q : matches)
+    sc_func_list.Append(q.second->m_sym_ctx);
 
-    if (target) {
-      if (ClangModulesDeclVendor *decl_vendor =
-              target->GetClangModulesDeclVendor()) {
-        decl_vendor->FindDecls(name, false, UINT32_MAX, decls_from_modules);
-      }
-    }
+  // Rejoin the lists with the functions in front.
+  sc_func_list.Append(sc_sym_list);
+  return sc_func_list;
+}
 
-    const bool include_inlines = false;
-    sc_list.Clear();
-    if (namespace_decl && module_sp) {
-      const bool include_symbols = false;
+void ClangExpressionDeclMap::LookupFunction(NameSearchContext &context,
+                                            lldb::ModuleSP module_sp,
+                                            ConstString name,
+                                            CompilerDeclContext &namespace_decl,
+                                            unsigned current_id) {
+  if (!m_parser_vars)
+    return;
 
-      module_sp->FindFunctions(name, &namespace_decl, eFunctionNameTypeBase,
-                               include_symbols, include_inlines, sc_list);
-    } else if (target && !namespace_decl) {
-      const bool include_symbols = true;
+  Target *target = m_parser_vars->m_exe_ctx.GetTargetPtr();
 
-      // TODO Fix FindFunctions so that it doesn't return
-      //   instance methods for eFunctionNameTypeBase.
+  std::vector<clang::NamedDecl *> decls_from_modules;
 
-      target->GetImages().FindFunctions(name, eFunctionNameTypeFull,
-                                        include_symbols, include_inlines,
-                                        sc_list);
+  if (target) {
+    if (ClangModulesDeclVendor *decl_vendor =
+            target->GetClangModulesDeclVendor()) {
+      decl_vendor->FindDecls(name, false, UINT32_MAX, decls_from_modules);
     }
+  }
 
-    // If we found more than one function, see if we can use the frame's decl
-    // context to remove functions that are shadowed by other functions which
-    // match in type but are nearer in scope.
-    //
-    // AddOneFunction will not add a function whose type has already been
-    // added, so if there's another function in the list with a matching type,
-    // check to see if their decl context is a parent of the current frame's or
-    // was imported via a and using statement, and pick the best match
-    // according to lookup rules.
-    if (sc_list.GetSize() > 1) {
-      // Collect some info about our frame's context.
-      StackFrame *frame = m_parser_vars->m_exe_ctx.GetFramePtr();
-      SymbolContext frame_sym_ctx;
-      if (frame != nullptr)
-        frame_sym_ctx = frame->GetSymbolContext(lldb::eSymbolContextFunction |
-                                                lldb::eSymbolContextBlock);
-      CompilerDeclContext frame_decl_context =
-          frame_sym_ctx.block != nullptr ? frame_sym_ctx.block->GetDeclContext()
-                                         : CompilerDeclContext();
-
-      // We can't do this without a compiler decl context for our frame.
-      if (frame_decl_context) {
-        clang::DeclContext *frame_decl_ctx =
-            (clang::DeclContext *)frame_decl_context.GetOpaqueDeclContext();
-        ClangASTContext *ast = llvm::dyn_cast_or_null<ClangASTContext>(
-            frame_decl_context.GetTypeSystem());
-
-        // Structure to hold the info needed when comparing function
-        // declarations.
-        struct FuncDeclInfo {
-          ConstString m_name;
-          CompilerType m_copied_type;
-          uint32_t m_decl_lvl;
-          SymbolContext m_sym_ctx;
-        };
-
-        // First, symplify things by looping through the symbol contexts to
-        // remove unwanted functions and separate out the functions we want to
-        // compare and prune into a separate list. Cache the info needed about
-        // the function declarations in a vector for efficiency.
-        SymbolContextList sc_sym_list;
-        uint32_t num_indices = sc_list.GetSize();
-        std::vector<FuncDeclInfo> fdi_cache;
-        fdi_cache.reserve(num_indices);
-        for (uint32_t index = 0; index < num_indices; ++index) {
-          FuncDeclInfo fdi;
-          SymbolContext sym_ctx;
-          sc_list.GetContextAtIndex(index, sym_ctx);
-
-          // We don't know enough about symbols to compare them, but we should
-          // keep them in the list.
-          Function *function = sym_ctx.function;
-          if (!function) {
-            sc_sym_list.Append(sym_ctx);
-            continue;
-          }
-          // Filter out functions without declaration contexts, as well as
-          // class/instance methods, since they'll be skipped in the code that
-          // follows anyway.
-          CompilerDeclContext func_decl_context = function->GetDeclContext();
-          if (!func_decl_context ||
-              func_decl_context.IsClassMethod(nullptr, nullptr, nullptr))
-            continue;
-          // We can only prune functions for which we can copy the type.
-          CompilerType func_clang_type =
-              function->GetType()->GetFullCompilerType();
-          CompilerType copied_func_type = GuardedCopyType(func_clang_type);
-          if (!copied_func_type) {
-            sc_sym_list.Append(sym_ctx);
-            continue;
-          }
+  const bool include_inlines = false;
+  SymbolContextList sc_list;
+  if (namespace_decl && module_sp) {
+    const bool include_symbols = false;
 
-          fdi.m_sym_ctx = sym_ctx;
-          fdi.m_name = function->GetName();
-          fdi.m_copied_type = copied_func_type;
-          fdi.m_decl_lvl = LLDB_INVALID_DECL_LEVEL;
-          if (fdi.m_copied_type && func_decl_context) {
-            // Call CountDeclLevels to get the number of parent scopes we have
-            // to look through before we find the function declaration. When
-            // comparing functions of the same type, the one with a lower count
-            // will be closer to us in the lookup scope and shadows the other.
-            clang::DeclContext *func_decl_ctx =
-                (clang::DeclContext *)func_decl_context.GetOpaqueDeclContext();
-            fdi.m_decl_lvl = ast->CountDeclLevels(
-                frame_decl_ctx, func_decl_ctx, &fdi.m_name, &fdi.m_copied_type);
-          }
-          fdi_cache.emplace_back(fdi);
-        }
+    module_sp->FindFunctions(name, &namespace_decl, eFunctionNameTypeBase,
+                             include_symbols, include_inlines, sc_list);
+  } else if (target && !namespace_decl) {
+    const bool include_symbols = true;
 
-        // Loop through the functions in our cache looking for matching types,
-        // then compare their scope levels to see which is closer.
-        std::multimap<CompilerType, const FuncDeclInfo *> matches;
-        for (const FuncDeclInfo &fdi : fdi_cache) {
-          const CompilerType t = fdi.m_copied_type;
-          auto q = matches.find(t);
-          if (q != matches.end()) {
-            if (q->second->m_decl_lvl > fdi.m_decl_lvl)
-              // This function is closer; remove the old set.
-              matches.erase(t);
-            else if (q->second->m_decl_lvl < fdi.m_decl_lvl)
-              // The functions in our set are closer - skip this one.
-              continue;
-          }
-          matches.insert(std::make_pair(t, &fdi));
-        }
+    // TODO Fix FindFunctions so that it doesn't return
+    //   instance methods for eFunctionNameTypeBase.
 
-        // Loop through our matches and add their symbol contexts to our list.
-        SymbolContextList sc_func_list;
-        for (const auto &q : matches)
-          sc_func_list.Append(q.second->m_sym_ctx);
+    target->GetImages().FindFunctions(
+        name, eFunctionNameTypeFull | eFunctionNameTypeBase, include_symbols,
+        include_inlines, sc_list);
+  }
 
-        // Rejoin the lists with the functions in front.
-        sc_list = sc_func_list;
-        sc_list.Append(sc_sym_list);
-      }
+  // If we found more than one function, see if we can use the frame's decl
+  // context to remove functions that are shadowed by other functions which
+  // match in type but are nearer in scope.
+  //
+  // AddOneFunction will not add a function whose type has already been
+  // added, so if there's another function in the list with a matching type,
+  // check to see if their decl context is a parent of the current frame's or
+  // was imported via a and using statement, and pick the best match
+  // according to lookup rules.
+  if (sc_list.GetSize() > 1) {
+    // Collect some info about our frame's context.
+    StackFrame *frame = m_parser_vars->m_exe_ctx.GetFramePtr();
+    SymbolContext frame_sym_ctx;
+    if (frame != nullptr)
+      frame_sym_ctx = frame->GetSymbolContext(lldb::eSymbolContextFunction |
+                                              lldb::eSymbolContextBlock);
+    CompilerDeclContext frame_decl_context =
+        frame_sym_ctx.block != nullptr ? frame_sym_ctx.block->GetDeclContext()
+                                       : CompilerDeclContext();
+
+    // We can't do this without a compiler decl context for our frame.
+    if (frame_decl_context) {
+      sc_list = SearchFunctionsInSymbolContexts(sc_list, frame_decl_context);
     }
+  }
 
-    if (sc_list.GetSize()) {
-      Symbol *extern_symbol = nullptr;
-      Symbol *non_extern_symbol = nullptr;
-
-      for (uint32_t index = 0, num_indices = sc_list.GetSize();
-           index < num_indices; ++index) {
-        SymbolContext sym_ctx;
-        sc_list.GetContextAtIndex(index, sym_ctx);
+  if (sc_list.GetSize()) {
+    Symbol *extern_symbol = nullptr;
+    Symbol *non_extern_symbol = nullptr;
 
-        if (sym_ctx.function) {
-          CompilerDeclContext decl_ctx = sym_ctx.function->GetDeclContext();
+    for (uint32_t index = 0, num_indices = sc_list.GetSize();
+         index < num_indices; ++index) {
+      SymbolContext sym_ctx;
+      sc_list.GetContextAtIndex(index, sym_ctx);
 
-          if (!decl_ctx)
-            continue;
+      if (sym_ctx.function) {
+        CompilerDeclContext decl_ctx = sym_ctx.function->GetDeclContext();
 
-          // Filter out class/instance methods.
-          if (decl_ctx.IsClassMethod(nullptr, nullptr, nullptr))
-            continue;
+        if (!decl_ctx)
+          continue;
 
-          AddOneFunction(context, sym_ctx.function, nullptr, current_id);
-          context.m_found.function_with_type_info = true;
-          context.m_found.function = true;
-        } else if (sym_ctx.symbol) {
-          if (sym_ctx.symbol->GetType() == eSymbolTypeReExported && target) {
-            sym_ctx.symbol = sym_ctx.symbol->ResolveReExportedSymbol(*target);
-            if (sym_ctx.symbol == nullptr)
-              continue;
-          }
+        // Filter out class/instance methods.
+        if (decl_ctx.IsClassMethod(nullptr, nullptr, nullptr))
+          continue;
 
-          if (sym_ctx.symbol->IsExternal())
-            extern_symbol = sym_ctx.symbol;
-          else
-            non_extern_symbol = sym_ctx.symbol;
+        AddOneFunction(context, sym_ctx.function, nullptr, current_id);
+        context.m_found.function_with_type_info = true;
+        context.m_found.function = true;
+      } else if (sym_ctx.symbol) {
+        if (sym_ctx.symbol->GetType() == eSymbolTypeReExported && target) {
+          sym_ctx.symbol = sym_ctx.symbol->ResolveReExportedSymbol(*target);
+          if (sym_ctx.symbol == nullptr)
+            continue;
         }
+
+        if (sym_ctx.symbol->IsExternal())
+          extern_symbol = sym_ctx.symbol;
+        else
+          non_extern_symbol = sym_ctx.symbol;
       }
+    }
 
-      if (!context.m_found.function_with_type_info) {
-        for (clang::NamedDecl *decl : decls_from_modules) {
-          if (llvm::isa<clang::FunctionDecl>(decl)) {
-            clang::NamedDecl *copied_decl =
-                llvm::cast_or_null<FunctionDecl>(CopyDecl(decl));
-            if (copied_decl) {
-              context.AddNamedDecl(copied_decl);
-              context.m_found.function_with_type_info = true;
-            }
+    if (!context.m_found.function_with_type_info) {
+      for (clang::NamedDecl *decl : decls_from_modules) {
+        if (llvm::isa<clang::FunctionDecl>(decl)) {
+          clang::NamedDecl *copied_decl =
+              llvm::cast_or_null<FunctionDecl>(CopyDecl(decl));
+          if (copied_decl) {
+            context.AddNamedDecl(copied_decl);
+            context.m_found.function_with_type_info = true;
           }
         }
       }
+    }
 
-      if (!context.m_found.function_with_type_info) {
-        if (extern_symbol) {
-          AddOneFunction(context, nullptr, extern_symbol, current_id);
-          context.m_found.function = true;
-        } else if (non_extern_symbol) {
-          AddOneFunction(context, nullptr, non_extern_symbol, current_id);
-          context.m_found.function = true;
-        }
+    if (!context.m_found.function_with_type_info) {
+      if (extern_symbol) {
+        AddOneFunction(context, nullptr, extern_symbol, current_id);
+        context.m_found.function = true;
+      } else if (non_extern_symbol) {
+        AddOneFunction(context, nullptr, non_extern_symbol, current_id);
+        context.m_found.function = true;
       }
     }
+  }
+}
 
-    if (!context.m_found.function_with_type_info) {
-      // Try the modules next.
+void ClangExpressionDeclMap::FindExternalVisibleDecls(
+    NameSearchContext &context, lldb::ModuleSP module_sp,
+    CompilerDeclContext &namespace_decl, unsigned int current_id) {
+  assert(m_ast_context);
 
-      do {
-        if (ClangModulesDeclVendor *modules_decl_vendor =
-                m_target->GetClangModulesDeclVendor()) {
-          bool append = false;
-          uint32_t max_matches = 1;
-          std::vector<clang::NamedDecl *> decls;
+  Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS));
 
-          if (!modules_decl_vendor->FindDecls(name, append, max_matches, decls))
-            break;
+  const ConstString name(context.m_decl_name.getAsString().c_str());
+  if (IgnoreName(name, false))
+    return;
 
-          clang::NamedDecl *const decl_from_modules = decls[0];
+  // Only look for functions by name out in our symbols if the function doesn't
+  // start with our phony prefix of '$'
 
-          if (llvm::isa<clang::FunctionDecl>(decl_from_modules)) {
-            if (log) {
-              LLDB_LOGF(log,
-                        "  CAS::FEVD[%u] Matching function found for "
-                        "\"%s\" in the modules",
-                        current_id, name.GetCString());
-            }
+  Target *target = nullptr;
+  StackFrame *frame = nullptr;
+  SymbolContext sym_ctx;
+  if (m_parser_vars) {
+    target = m_parser_vars->m_exe_ctx.GetTargetPtr();
+    frame = m_parser_vars->m_exe_ctx.GetFramePtr();
+  }
+  if (frame != nullptr)
+    sym_ctx = frame->GetSymbolContext(lldb::eSymbolContextFunction |
+                                      lldb::eSymbolContextBlock);
 
-            clang::Decl *copied_decl = CopyDecl(decl_from_modules);
-            clang::FunctionDecl *copied_function_decl =
-                copied_decl ? dyn_cast<clang::FunctionDecl>(copied_decl)
-                            : nullptr;
+  // Try the persistent decls, which take precedence over all else.
+  if (!namespace_decl)
+    SearchPersistenDecls(context, name, current_id);
 
-            if (!copied_function_decl) {
-              LLDB_LOGF(log,
-                        "  CAS::FEVD[%u] - Couldn't export a function "
-                        "declaration from the modules",
-                        current_id);
+  if (name.GetStringRef().startswith("$") && !namespace_decl) {
+    if (name == "$__lldb_class") {
+      LookUpLldbClass(context, current_id);
+      return;
+    }
 
-              break;
-            }
+    if (name == "$__lldb_objc_class") {
+      LookUpLldbObjCClass(context, current_id);
+      return;
+    }
+    if (name == g_lldb_local_vars_namespace_cstr) {
+      LookupLocalVarNamespace(sym_ctx, context);
+      return;
+    }
+
+    // any other $__lldb names should be weeded out now
+    if (name.GetStringRef().startswith("$__lldb"))
+      return;
 
-            MaybeRegisterFunctionBody(copied_function_decl);
+    // No ParserVars means we can't do register or variable lookup.
+    if (!m_parser_vars || !m_parser_vars->m_persistent_vars)
+      return;
 
-            context.AddNamedDecl(copied_function_decl);
+    ExpressionVariableSP pvar_sp(
+        m_parser_vars->m_persistent_vars->GetVariable(name));
 
-            context.m_found.function_with_type_info = true;
-            context.m_found.function = true;
-          } else if (llvm::isa<clang::VarDecl>(decl_from_modules)) {
-            if (log) {
-              LLDB_LOGF(log,
-                        "  CAS::FEVD[%u] Matching variable found for "
-                        "\"%s\" in the modules",
-                        current_id, name.GetCString());
-            }
+    if (pvar_sp) {
+      AddOneVariable(context, pvar_sp, current_id);
+      return;
+    }
 
-            clang::Decl *copied_decl = CopyDecl(decl_from_modules);
-            clang::VarDecl *copied_var_decl =
-                copied_decl ? dyn_cast_or_null<clang::VarDecl>(copied_decl)
-                            : nullptr;
+    assert(name.GetStringRef().startswith("$"));
+    llvm::StringRef reg_name = name.GetStringRef().substr(1);
 
-            if (!copied_var_decl) {
-              LLDB_LOGF(log,
-                        "  CAS::FEVD[%u] - Couldn't export a variable "
-                        "declaration from the modules",
-                        current_id);
+    if (m_parser_vars->m_exe_ctx.GetRegisterContext()) {
+      const RegisterInfo *reg_info(
+          m_parser_vars->m_exe_ctx.GetRegisterContext()->GetRegisterInfoByName(
+              reg_name));
 
-              break;
-            }
+      if (reg_info) {
+        LLDB_LOGF(log, "  CEDM::FEVD[%u] Found register %s", current_id,
+                  reg_info->name);
 
-            context.AddNamedDecl(copied_var_decl);
+        AddOneRegister(context, reg_info, current_id);
+      }
+    }
+    return;
+  }
 
-            context.m_found.variable = true;
-          }
-        }
-      } while (false);
+  bool local_var_lookup = !namespace_decl || (namespace_decl.GetName() ==
+                                              g_lldb_local_vars_namespace_cstr);
+  if (frame && local_var_lookup)
+    if (LookupLocalVariable(context, name, current_id, sym_ctx, namespace_decl))
+      return;
+
+  if (target) {
+    ValueObjectSP valobj;
+    VariableSP var;
+    var = FindGlobalVariable(*target, module_sp, name, &namespace_decl);
+
+    if (var) {
+      valobj = ValueObjectVariable::Create(target, var);
+      AddOneVariable(context, var, valobj, current_id);
+      context.m_found.variable = true;
+      return;
     }
+  }
 
-    if (target && !context.m_found.variable && !namespace_decl) {
-      // We couldn't find a non-symbol variable for this.  Now we'll hunt for a
-      // generic data symbol, and -- if it is found -- treat it as a variable.
-      Status error;
+  LookupFunction(context, module_sp, name, namespace_decl, current_id);
 
-      const Symbol *data_symbol =
-          m_parser_vars->m_sym_ctx.FindBestGlobalDataSymbol(name, error);
+  // Try the modules next.
+  if (!context.m_found.function_with_type_info)
+    LookupInModulesDeclVendor(context, name, current_id);
 
-      if (!error.Success()) {
-        const unsigned diag_id =
-            m_ast_context->getDiagnostics().getCustomDiagID(
-                clang::DiagnosticsEngine::Level::Error, "%0");
-        m_ast_context->getDiagnostics().Report(diag_id) << error.AsCString();
-      }
+  if (target && !context.m_found.variable && !namespace_decl) {
+    // We couldn't find a non-symbol variable for this.  Now we'll hunt for a
+    // generic data symbol, and -- if it is found -- treat it as a variable.
+    Status error;
 
-      if (data_symbol) {
-        std::string warning("got name from symbols: ");
-        warning.append(name.AsCString());
-        const unsigned diag_id =
-            m_ast_context->getDiagnostics().getCustomDiagID(
-                clang::DiagnosticsEngine::Level::Warning, "%0");
-        m_ast_context->getDiagnostics().Report(diag_id) << warning.c_str();
-        AddOneGenericVariable(context, *data_symbol, current_id);
-        context.m_found.variable = true;
-      }
+    const Symbol *data_symbol =
+        m_parser_vars->m_sym_ctx.FindBestGlobalDataSymbol(name, error);
+
+    if (!error.Success()) {
+      const unsigned diag_id =
+          m_ast_context->getDiagnostics().getCustomDiagID(
+              clang::DiagnosticsEngine::Level::Error, "%0");
+      m_ast_context->getDiagnostics().Report(diag_id) << error.AsCString();
+    }
+
+    if (data_symbol) {
+      std::string warning("got name from symbols: ");
+      warning.append(name.AsCString());
+      const unsigned diag_id =
+          m_ast_context->getDiagnostics().getCustomDiagID(
+              clang::DiagnosticsEngine::Level::Warning, "%0");
+      m_ast_context->getDiagnostics().Report(diag_id) << warning.c_str();
+      AddOneGenericVariable(context, *data_symbol, current_id);
+      context.m_found.variable = true;
     }
   }
 }
@@ -1543,15 +1508,6 @@ bool ClangExpressionDeclMap::GetVariableValue(VariableSP &var,
     return false;
   }
 
-  ASTContext *ast = clang_ast->getASTContext();
-
-  if (!ast) {
-    if (log)
-      log->PutCString(
-          "There is no AST context for the current execution context");
-    return false;
-  }
-
   DWARFExpression &var_location_expr = var->LocationExpression();
 
   Target *target = m_parser_vars->m_exe_ctx.GetTargetPtr();
@@ -1664,14 +1620,10 @@ void ClangExpressionDeclMap::AddOneVariable(NameSearchContext &context,
   if (is_reference)
     entity->m_flags |= ClangExpressionVariable::EVTypeIsReference;
 
-  if (log) {
-    ASTDumper orig_dumper(ut.GetOpaqueQualType());
-    ASTDumper ast_dumper(var_decl);
-    LLDB_LOGF(log,
-              "  CEDM::FEVD[%u] Found variable %s, returned %s (original %s)",
-              current_id, decl_name.c_str(), ast_dumper.GetCString(),
-              orig_dumper.GetCString());
-  }
+  LLDB_LOG(log,
+           "  CEDM::FEVD[{0}] Found variable {1}, returned\n{2} (original {3})",
+           current_id, decl_name, ClangUtil::DumpDecl(var_decl),
+           ClangUtil::ToString(ut));
 }
 
 void ClangExpressionDeclMap::AddOneVariable(NameSearchContext &context,
@@ -1703,11 +1655,8 @@ void ClangExpressionDeclMap::AddOneVariable(NameSearchContext &context,
   parser_vars->m_llvm_value = nullptr;
   parser_vars->m_lldb_value.Clear();
 
-  if (log) {
-    ASTDumper ast_dumper(var_decl);
-    LLDB_LOGF(log, "  CEDM::FEVD[%u] Added pvar %s, returned %s", current_id,
-              pvar_sp->GetName().GetCString(), ast_dumper.GetCString());
-  }
+  LLDB_LOG(log, "  CEDM::FEVD[{0}] Added pvar {1}, returned\n{2}", current_id,
+           pvar_sp->GetName(), ClangUtil::DumpDecl(var_decl));
 }
 
 void ClangExpressionDeclMap::AddOneGenericVariable(NameSearchContext &context,
@@ -1722,17 +1671,16 @@ void ClangExpressionDeclMap::AddOneGenericVariable(NameSearchContext &context,
   if (target == nullptr)
     return;
 
-  ASTContext *scratch_ast_context =
-      target->GetScratchClangASTContext()->getASTContext();
+  ClangASTContext *scratch_ast_context = ClangASTContext::GetScratch(*target);
+  if (!scratch_ast_context)
+    return;
 
-  TypeFromUser user_type(
-      ClangASTContext::GetBasicType(scratch_ast_context, eBasicTypeVoid)
-          .GetPointerType()
-          .GetLValueReferenceType());
-  TypeFromParser parser_type(
-      ClangASTContext::GetBasicType(m_ast_context, eBasicTypeVoid)
-          .GetPointerType()
-          .GetLValueReferenceType());
+  TypeFromUser user_type(scratch_ast_context->GetBasicType(eBasicTypeVoid)
+                             .GetPointerType()
+                             .GetLValueReferenceType());
+  TypeFromParser parser_type(m_clang_ast_context->GetBasicType(eBasicTypeVoid)
+                                 .GetPointerType()
+                                 .GetLValueReferenceType());
   NamedDecl *var_decl = context.AddVarDecl(parser_type);
 
   std::string decl_name(context.m_decl_name.getAsString());
@@ -1761,86 +1709,8 @@ void ClangExpressionDeclMap::AddOneGenericVariable(NameSearchContext &context,
   parser_vars->m_llvm_value = nullptr;
   parser_vars->m_lldb_sym = &symbol;
 
-  if (log) {
-    ASTDumper ast_dumper(var_decl);
-
-    LLDB_LOGF(log, "  CEDM::FEVD[%u] Found variable %s, returned %s",
-              current_id, decl_name.c_str(), ast_dumper.GetCString());
-  }
-}
-
-bool ClangExpressionDeclMap::ResolveUnknownTypes() {
-  Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS));
-  Target *target = m_parser_vars->m_exe_ctx.GetTargetPtr();
-
-  ClangASTContextForExpressions *scratch_ast_context =
-      static_cast<ClangASTContextForExpressions *>(
-          target->GetScratchClangASTContext());
-
-  for (size_t index = 0, num_entities = m_found_entities.GetSize();
-       index < num_entities; ++index) {
-    ExpressionVariableSP entity = m_found_entities.GetVariableAtIndex(index);
-
-    ClangExpressionVariable::ParserVars *parser_vars =
-        llvm::cast<ClangExpressionVariable>(entity.get())
-            ->GetParserVars(GetParserID());
-
-    if (entity->m_flags & ClangExpressionVariable::EVUnknownType) {
-      const NamedDecl *named_decl = parser_vars->m_named_decl;
-      const VarDecl *var_decl = dyn_cast<VarDecl>(named_decl);
-
-      if (!var_decl) {
-        LLDB_LOGF(log, "Entity of unknown type does not have a VarDecl");
-        return false;
-      }
-
-      if (log) {
-        ASTDumper ast_dumper(const_cast<VarDecl *>(var_decl));
-        LLDB_LOGF(log, "Variable of unknown type now has Decl %s",
-                  ast_dumper.GetCString());
-      }
-
-      QualType var_type = var_decl->getType();
-      TypeFromParser parser_type(
-          var_type.getAsOpaquePtr(),
-          ClangASTContext::GetASTContext(&var_decl->getASTContext()));
-
-      lldb::opaque_compiler_type_t copied_type = nullptr;
-      if (m_ast_importer_sp) {
-        copied_type = m_ast_importer_sp->CopyType(
-            scratch_ast_context->getASTContext(), &var_decl->getASTContext(),
-            var_type.getAsOpaquePtr());
-      } else if (HasMerger()) {
-        copied_type = CopyTypeWithMerger(
-                          var_decl->getASTContext(),
-                          scratch_ast_context->GetMergerUnchecked(), var_type)
-                          .getAsOpaquePtr();
-      } else {
-        lldbassert(0 && "No mechanism to copy a resolved unknown type!");
-        return false;
-      }
-
-      if (!copied_type) {
-        LLDB_LOGF(log, "ClangExpressionDeclMap::ResolveUnknownType - Couldn't "
-                       "import the type for a variable");
-
-        return (bool)lldb::ExpressionVariableSP();
-      }
-
-      TypeFromUser user_type(copied_type, scratch_ast_context);
-
-      //            parser_vars->m_lldb_value.SetContext(Value::eContextTypeClangType,
-      //            user_type.GetOpaqueQualType());
-      parser_vars->m_lldb_value.SetCompilerType(user_type);
-      parser_vars->m_parser_type = parser_type;
-
-      entity->SetCompilerType(user_type);
-
-      entity->m_flags &= ~(ClangExpressionVariable::EVUnknownType);
-    }
-  }
-
-  return true;
+  LLDB_LOG(log, "  CEDM::FEVD[{0}] Found variable {1}, returned\n{2}",
+           current_id, decl_name, ClangUtil::DumpDecl(var_decl));
 }
 
 void ClangExpressionDeclMap::AddOneRegister(NameSearchContext &context,
@@ -1849,8 +1719,8 @@ void ClangExpressionDeclMap::AddOneRegister(NameSearchContext &context,
   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS));
 
   CompilerType clang_type =
-      ClangASTContext::GetBuiltinTypeForEncodingAndBitSize(
-          m_ast_context, reg_info->encoding, reg_info->byte_size * 8);
+      m_clang_ast_context->GetBuiltinTypeForEncodingAndBitSize(
+          reg_info->encoding, reg_info->byte_size * 8);
 
   if (!clang_type) {
     LLDB_LOGF(log, "  Tried to add a type for %s, but couldn't get one",
@@ -1880,12 +1750,9 @@ void ClangExpressionDeclMap::AddOneRegister(NameSearchContext &context,
   parser_vars->m_lldb_value.Clear();
   entity->m_flags |= ClangExpressionVariable::EVBareRegister;
 
-  if (log) {
-    ASTDumper ast_dumper(var_decl);
-    LLDB_LOGF(log, "  CEDM::FEVD[%d] Added register %s, returned %s",
-              current_id, context.m_decl_name.getAsString().c_str(),
-              ast_dumper.GetCString());
-  }
+  LLDB_LOG(log, "  CEDM::FEVD[{0}] Added register {1}, returned\n{2}",
+           current_id, context.m_decl_name.getAsString(),
+           ClangUtil::DumpDecl(var_decl));
 }
 
 void ClangExpressionDeclMap::AddOneFunction(NameSearchContext &context,
@@ -1928,17 +1795,16 @@ void ClangExpressionDeclMap::AddOneFunction(NameSearchContext &context,
                   CopyDecl(function_template));
           if (copied_function_template) {
             if (log) {
-              ASTDumper ast_dumper((clang::Decl *)copied_function_template);
-
               StreamString ss;
 
               function->DumpSymbolContext(&ss);
 
-              log->Printf("  CEDM::FEVD[%u] Imported decl for function template"
-                          " %s (description %s), returned %s",
-                          current_id,
-                          copied_function_template->getNameAsString().c_str(),
-                          ss.GetData(), ast_dumper.GetCString());
+              LLDB_LOG(log,
+                       "  CEDM::FEVD[{0}] Imported decl for function template"
+                       " {1} (description {2}), returned\n{3}",
+                       current_id, copied_function_template->getNameAsString(),
+                       ss.GetData(),
+                       ClangUtil::DumpDecl(copied_function_template));
             }
 
             context.AddNamedDecl(copied_function_template);
@@ -1948,18 +1814,15 @@ void ClangExpressionDeclMap::AddOneFunction(NameSearchContext &context,
                   llvm::dyn_cast_or_null<clang::FunctionDecl>(
                       CopyDecl(src_function_decl))) {
             if (log) {
-              ASTDumper ast_dumper((clang::Decl *)copied_function_decl);
-
               StreamString ss;
 
               function->DumpSymbolContext(&ss);
 
-              LLDB_LOGF(log,
-                        "  CEDM::FEVD[%u] Imported decl for function %s "
-                        "(description %s), returned %s",
-                        current_id,
-                        copied_function_decl->getNameAsString().c_str(),
-                        ss.GetData(), ast_dumper.GetCString());
+              LLDB_LOG(log,
+                       "  CEDM::FEVD[{0}]] Imported decl for function {1} "
+                       "(description {2}), returned\n{3}",
+                       current_id, copied_function_decl->getNameAsString(),
+                       ss.GetData(), ClangUtil::DumpDecl(copied_function_decl));
             }
 
             context.AddNamedDecl(copied_function_decl);
@@ -2061,20 +1924,17 @@ void ClangExpressionDeclMap::AddOneFunction(NameSearchContext &context,
   parser_vars->m_llvm_value = nullptr;
 
   if (log) {
-    std::string function_str =
-        function_decl ? ASTDumper(function_decl).GetCString() : "nullptr";
-
     StreamString ss;
 
     fun_address.Dump(&ss,
                      m_parser_vars->m_exe_ctx.GetBestExecutionContextScope(),
                      Address::DumpStyleResolvedDescription);
 
-    LLDB_LOGF(
-        log,
-        "  CEDM::FEVD[%u] Found %s function %s (description %s), returned %s",
-        current_id, (function ? "specific" : "generic"), decl_name.c_str(),
-        ss.GetData(), function_str.c_str());
+    LLDB_LOG(log,
+             "  CEDM::FEVD[{0}] Found {1} function {2} (description {3}), "
+             "returned\n{4}",
+             current_id, (function ? "specific" : "generic"), decl_name,
+             ss.GetData(), ClangUtil::DumpDecl(function_decl));
   }
 }
 
@@ -2097,11 +1957,11 @@ void ClangExpressionDeclMap::AddThisType(NameSearchContext &context,
   if (copied_clang_type.IsAggregateType() &&
       copied_clang_type.GetCompleteType()) {
     CompilerType void_clang_type =
-        ClangASTContext::GetBasicType(m_ast_context, eBasicTypeVoid);
+        m_clang_ast_context->GetBasicType(eBasicTypeVoid);
     CompilerType void_ptr_clang_type = void_clang_type.GetPointerType();
 
-    CompilerType method_type = ClangASTContext::CreateFunctionType(
-        m_ast_context, void_clang_type, &void_ptr_clang_type, 1, false, 0);
+    CompilerType method_type = m_clang_ast_context->CreateFunctionType(
+        void_clang_type, &void_ptr_clang_type, 1, false, 0);
 
     const bool is_virtual = false;
     const bool is_static = false;
@@ -2110,22 +1970,16 @@ void ClangExpressionDeclMap::AddThisType(NameSearchContext &context,
     const bool is_attr_used = true;
     const bool is_artificial = false;
 
-    CXXMethodDecl *method_decl =
-        ClangASTContext::GetASTContext(m_ast_context)
-            ->AddMethodToCXXRecordType(
-                copied_clang_type.GetOpaqueQualType(), "$__lldb_expr", nullptr,
-                method_type, lldb::eAccessPublic, is_virtual, is_static,
-                is_inline, is_explicit, is_attr_used, is_artificial);
-
-    if (log) {
-      ASTDumper method_ast_dumper((clang::Decl *)method_decl);
-      ASTDumper type_ast_dumper(copied_clang_type);
+    CXXMethodDecl *method_decl = m_clang_ast_context->AddMethodToCXXRecordType(
+        copied_clang_type.GetOpaqueQualType(), "$__lldb_expr", nullptr,
+        method_type, lldb::eAccessPublic, is_virtual, is_static, is_inline,
+        is_explicit, is_attr_used, is_artificial);
 
-      LLDB_LOGF(log,
-                "  CEDM::AddThisType Added function $__lldb_expr "
-                "(description %s) for this type %s",
-                method_ast_dumper.GetCString(), type_ast_dumper.GetCString());
-    }
+    LLDB_LOG(log,
+             "  CEDM::AddThisType Added function $__lldb_expr "
+             "(description {0}) for this type\n{1}",
+             ClangUtil::ToString(copied_clang_type),
+             ClangUtil::DumpDecl(method_decl));
   }
 
   if (!copied_clang_type.IsValid())
diff --git a/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionDeclMap.h b/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionDeclMap.h
index 2711e90726e7..722f5e15a2aa 100644
--- a/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionDeclMap.h
+++ b/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionDeclMap.h
@@ -63,12 +63,15 @@ public:
   ///     the result persistent variable, and instead marks the variable
   ///     as persisting.
   ///
-  /// \param[in] delegate
+  /// \param[in] result_delegate
   ///     If non-NULL, use this delegate to report result values.  This
   ///     allows the client ClangUserExpression to report a result.
   ///
-  /// \param[in] exe_ctx
-  ///     The execution context to use when parsing.
+  /// \param[in] target
+  ///     The target to use when parsing.
+  ///
+  /// \param[in] importer
+  ///     The ClangASTImporter to use when parsing.
   ///
   /// \param[in] ctx_obj
   ///     If not empty, then expression is evaluated in context of this object.
@@ -76,7 +79,7 @@ public:
   ClangExpressionDeclMap(
       bool keep_result_in_memory,
       Materializer::PersistentVariableDelegate *result_delegate,
-      ExecutionContext &exe_ctx,
+      const lldb::TargetSP &target, const lldb::ClangASTImporterSP &importer,
       ValueObject *ctx_obj);
 
   /// Destructor
@@ -98,13 +101,6 @@ public:
 
   void InstallCodeGenerator(clang::ASTConsumer *code_gen);
 
-  /// [Used by ClangExpressionParser] For each variable that had an unknown
-  ///     type at the beginning of parsing, determine its final type now.
-  ///
-  /// \return
-  ///     True on success; false otherwise.
-  bool ResolveUnknownTypes();
-
   /// Disable the state needed for parsing and IR transformation.
   void DidParse();
 
@@ -248,17 +244,6 @@ public:
   lldb::addr_t GetSymbolAddress(ConstString name,
                                 lldb::SymbolType symbol_type);
 
-  /// [Used by IRInterpreter] Get basic target information.
-  ///
-  /// \param[out] byte_order
-  ///     The byte order of the target.
-  ///
-  /// \param[out] address_byte_size
-  ///     The size of a pointer in bytes.
-  ///
-  /// \return
-  ///     True if the information could be determined; false
-  ///     otherwise.
   struct TargetInfo {
     lldb::ByteOrder byte_order;
     size_t address_byte_size;
@@ -276,9 +261,6 @@ public:
   ///
   /// \param[in] context
   ///     The NameSearchContext that can construct Decls for this name.
-  ///
-  /// \return
-  ///     True on success; false otherwise.
   void FindExternalVisibleDecls(NameSearchContext &context) override;
 
   /// Find all entities matching a given name in a given module/namespace,
@@ -296,14 +278,19 @@ public:
   /// \param[in] current_id
   ///     The ID for the current FindExternalVisibleDecls invocation,
   ///     for logging purposes.
-  ///
-  /// \return
-  ///     True on success; false otherwise.
   void FindExternalVisibleDecls(NameSearchContext &context,
                                 lldb::ModuleSP module,
                                 CompilerDeclContext &namespace_decl,
                                 unsigned int current_id);
 
+protected:
+  /// Retrieves the declaration with the given name from the storage of
+  /// persistent declarations.
+  ///
+  /// \return
+  ///     A persistent decl with the given name or a nullptr.
+  virtual clang::NamedDecl *GetPersistentDecl(ConstString name);
+
 private:
   ExpressionVariableList
       m_found_entities; ///< All entities that were looked up for the parser.
@@ -329,7 +316,7 @@ private:
       if (m_exe_ctx.GetTargetPtr())
         return m_exe_ctx.GetTargetPtr();
       else if (m_sym_ctx.target_sp)
-        m_sym_ctx.target_sp.get();
+        return m_sym_ctx.target_sp.get();
       return nullptr;
     }
 
@@ -396,6 +383,130 @@ private:
   /// from persistent variables.
   uint64_t GetParserID() { return (uint64_t) this; }
 
+  /// Should be called on all copied functions.
+  void MaybeRegisterFunctionBody(clang::FunctionDecl *copied_function_decl);
+
+  /// Searches the persistent decls of the target for entities with the
+  /// given name.
+  ///
+  /// \param[in] context
+  ///     The NameSearchContext that can construct Decls for this name.
+  ///
+  /// \param[in] name
+  ///     The name of the entities that need to be found.
+  ///
+  /// \param[in] current_id
+  ///     The ID for the current FindExternalVisibleDecls invocation,
+  ///     for logging purposes.
+  void SearchPersistenDecls(NameSearchContext &context, const ConstString name,
+                            unsigned int current_id);
+
+  /// Handles looking up $__lldb_class which requires special treatment.
+  ///
+  /// \param[in] context
+  ///     The NameSearchContext that can construct Decls for this name.
+  ///
+  /// \param[in] current_id
+  ///     The ID for the current FindExternalVisibleDecls invocation,
+  ///     for logging purposes.
+  void LookUpLldbClass(NameSearchContext &context, unsigned int current_id);
+
+  /// Handles looking up $__lldb_objc_class which requires special treatment.
+  ///
+  /// \param[in] context
+  ///     The NameSearchContext that can construct Decls for this name.
+  ///
+  /// \param[in] current_id
+  ///     The ID for the current FindExternalVisibleDecls invocation,
+  ///     for logging purposes.
+  void LookUpLldbObjCClass(NameSearchContext &context, unsigned int current_id);
+
+  /// Handles looking up the synthetic namespace that contains our local
+  /// variables for the current frame.
+  ///
+  /// \param[in] sym_ctx
+  ///     The current SymbolContext of this frame.
+  ///
+  /// \param[in] name_context
+  ///     The NameSearchContext that can construct Decls for this name.
+  void LookupLocalVarNamespace(SymbolContext &sym_ctx,
+                               NameSearchContext &name_context);
+
+  /// Lookup entities in the ClangModulesDeclVendor.
+  /// \param[in] context
+  ///     The NameSearchContext that can construct Decls for this name.
+  ///
+  /// \param[in] name
+  ///     The name of the entities that need to be found.
+  ///
+  /// \param[in] current_id
+  ///     The ID for the current FindExternalVisibleDecls invocation,
+  ///     for logging purposes.
+  void LookupInModulesDeclVendor(NameSearchContext &context, ConstString name,
+                                 unsigned current_id);
+
+  /// Looks up a local variable.
+  ///
+  /// \param[in] context
+  ///     The NameSearchContext that can construct Decls for this name.
+  ///
+  /// \param[in] name
+  ///     The name of the entities that need to be found.
+  ///
+  /// \param[in] current_id
+  ///     The ID for the current FindExternalVisibleDecls invocation,
+  ///     for logging purposes.
+  ///
+  /// \param[in] sym_ctx
+  ///     The current SymbolContext of this frame.
+  ///
+  /// \param[in] namespace_decl
+  ///     The parent namespace if there is one.
+  ///
+  /// \return
+  ///    True iff a local variable was found.
+  bool LookupLocalVariable(NameSearchContext &context, ConstString name,
+                           unsigned current_id, SymbolContext &sym_ctx,
+                           CompilerDeclContext &namespace_decl);
+
+  /// Searches for functions in the given SymbolContextList.
+  ///
+  /// \param[in] sc_list
+  ///     The SymbolContextList to search.
+  ///
+  /// \param[in] frame_decl_context
+  ///     The current DeclContext of the current frame.
+  ///
+  /// \return
+  ///     A SymbolContextList with any found functions in the front and
+  ///     any unknown SymbolContexts which are not functions in the back.
+  ///     The SymbolContexts for the functions are ordered by how close they are
+  ///     to the DeclContext for the given frame DeclContext.
+  SymbolContextList SearchFunctionsInSymbolContexts(
+      const SymbolContextList &sc_list,
+      const CompilerDeclContext &frame_decl_context);
+
+  /// Looks up a function.
+  ///
+  /// \param[in] context
+  ///     The NameSearchContext that can construct Decls for this name.
+  ///
+  /// \param[in] module_sp
+  ///     If non-NULL, the module to query.
+  ///
+  /// \param[in] name
+  ///     The name of the function that should be find.
+  ///
+  /// \param[in] namespace_decl
+  ///     If valid and module is non-NULL, the parent namespace.
+  ///
+  /// \param[in] current_id
+  ///     The ID for the current FindExternalVisibleDecls invocation,
+  ///     for logging purposes.
+  void LookupFunction(NameSearchContext &context, lldb::ModuleSP module_sp,
+                      ConstString name, CompilerDeclContext &namespace_decl,
+                      unsigned current_id);
+
   /// Given a target, find a variable that matches the given name and type.
   ///
   /// \param[in] target
@@ -410,17 +521,11 @@ private:
   /// \param[in] namespace_decl
   ///     If non-NULL and module is non-NULL, the parent namespace.
   ///
-  /// \param[in] type
-  ///     The required type for the variable.  This function may be called
-  ///     during parsing, in which case we don't know its type; hence the
-  ///     default.
-  ///
   /// \return
   ///     The LLDB Variable found, or NULL if none was found.
   lldb::VariableSP FindGlobalVariable(Target &target, lldb::ModuleSP &module,
                                       ConstString name,
-                                      CompilerDeclContext *namespace_decl,
-                                      TypeFromUser *type = nullptr);
+                                      CompilerDeclContext *namespace_decl);
 
   /// Get the value of a variable in a given execution context and return the
   /// associated Types if needed.
@@ -441,9 +546,6 @@ private:
   ///     AST context.  This is only useful when the variable is being
   ///     inspected on behalf of the parser, hence the default.
   ///
-  /// \param[in] decl
-  ///     The Decl to be looked up.
-  ///
   /// \return
   ///     Return true if the value was successfully filled in.
   bool GetVariableValue(lldb::VariableSP &var,
@@ -471,7 +573,7 @@ private:
   /// \param[in] context
   ///     The NameSearchContext to use when constructing the Decl.
   ///
-  /// \param[in] pvar
+  /// \param[in] pvar_sp
   ///     The persistent variable that needs a Decl.
   ///
   /// \param[in] current_id
@@ -483,12 +585,6 @@ private:
 
   /// Use the NameSearchContext to generate a Decl for the given LLDB symbol
   /// (treated as a variable), and put it in the list of found entities.
-  ///
-  /// \param[in] context
-  ///     The NameSearchContext to use when constructing the Decl.
-  ///
-  /// \param[in] var
-  ///     The LLDB Variable that needs a Decl.
   void AddOneGenericVariable(NameSearchContext &context, const Symbol &symbol,
                              unsigned int current_id);
 
diff --git a/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionParser.cpp b/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionParser.cpp
index 1422911d6546..8abd14942885 100644
--- a/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionParser.cpp
+++ b/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionParser.cpp
@@ -10,6 +10,7 @@
 #include "clang/AST/ASTDiagnostic.h"
 #include "clang/AST/ExternalASTSource.h"
 #include "clang/AST/PrettyPrinter.h"
+#include "clang/Basic/Builtins.h"
 #include "clang/Basic/DiagnosticIDs.h"
 #include "clang/Basic/SourceLocation.h"
 #include "clang/Basic/TargetInfo.h"
@@ -582,15 +583,16 @@ ClangExpressionParser::ClangExpressionParser(
 
   if (ClangModulesDeclVendor *decl_vendor =
           target_sp->GetClangModulesDeclVendor()) {
-    ClangPersistentVariables *clang_persistent_vars =
-        llvm::cast<ClangPersistentVariables>(
+    if (auto *clang_persistent_vars = llvm::cast<ClangPersistentVariables>(
             target_sp->GetPersistentExpressionStateForLanguage(
-                lldb::eLanguageTypeC));
-    std::unique_ptr<PPCallbacks> pp_callbacks(new LLDBPreprocessorCallbacks(
-        *decl_vendor, *clang_persistent_vars, m_compiler->getSourceManager()));
-    m_pp_callbacks =
-        static_cast<LLDBPreprocessorCallbacks *>(pp_callbacks.get());
-    m_compiler->getPreprocessor().addPPCallbacks(std::move(pp_callbacks));
+                lldb::eLanguageTypeC))) {
+      std::unique_ptr<PPCallbacks> pp_callbacks(
+          new LLDBPreprocessorCallbacks(*decl_vendor, *clang_persistent_vars,
+                                        m_compiler->getSourceManager()));
+      m_pp_callbacks =
+          static_cast<LLDBPreprocessorCallbacks *>(pp_callbacks.get());
+      m_compiler->getPreprocessor().addPPCallbacks(std::move(pp_callbacks));
+    }
   }
 
   // 8. Most of this we get from the CompilerInstance, but we also want to give
@@ -696,10 +698,7 @@ class CodeComplete : public CodeCompleteConsumer {
 
 public:
   /// Constructs a CodeComplete consumer that can be attached to a Sema.
-  /// \param[out] matches
-  ///    The list of matches that the lldb completion API expects as a result.
-  ///    This may already contain matches, so it's only allowed to append
-  ///    to this variable.
+  ///
   /// \param[out] expr
   ///    The whole expression string that we are currently parsing. This
   ///    string needs to be equal to the input the user typed, and NOT the
@@ -976,7 +975,7 @@ ClangExpressionParser::ParseInternal(DiagnosticManager &diagnostic_manager,
   m_compiler->setASTConsumer(std::move(Consumer));
 
   if (ast_context.getLangOpts().Modules) {
-    m_compiler->createModuleManager();
+    m_compiler->createASTReader();
     m_ast_context->setSema(&m_compiler->getSema());
   }
 
@@ -999,7 +998,7 @@ ClangExpressionParser::ParseInternal(DiagnosticManager &diagnostic_manager,
     } else {
       ast_context.setExternalSource(ast_source);
     }
-    decl_map->InstallASTContext(ast_context, m_compiler->getFileManager());
+    decl_map->InstallASTContext(*m_ast_context);
   }
 
   // Check that the ASTReader is properly attached to ASTContext and Sema.
@@ -1036,15 +1035,6 @@ ClangExpressionParser::ParseInternal(DiagnosticManager &diagnostic_manager,
   }
 
   if (!num_errors) {
-    if (type_system_helper->DeclMap() &&
-        !type_system_helper->DeclMap()->ResolveUnknownTypes()) {
-      diagnostic_manager.Printf(eDiagnosticSeverityError,
-                                "Couldn't infer the type of a variable");
-      num_errors++;
-    }
-  }
-
-  if (!num_errors) {
     type_system_helper->CommitPersistentDecls();
   }
 
@@ -1268,8 +1258,9 @@ lldb_private::Status ClangExpressionParser::PrepareForExecution(
           interpret_error, interpret_function_calls);
 
       if (!can_interpret && execution_policy == eExecutionPolicyNever) {
-        err.SetErrorStringWithFormat("Can't run the expression locally: %s",
-                                     interpret_error.AsCString());
+        err.SetErrorStringWithFormat(
+            "Can't evaluate the expression without a running target due to: %s",
+            interpret_error.AsCString());
         return err;
       }
     }
diff --git a/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionParser.h b/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionParser.h
index 79ad5728bf74..4a410cecb94a 100644
--- a/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionParser.h
+++ b/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionParser.h
@@ -42,7 +42,7 @@ public:
   ///
   /// Initializes class variables.
   ///
-  /// \param[in] exe_scope,
+  /// \param[in] exe_scope
   ///     If non-NULL, an execution context scope that can help to
   ///     correctly create an expression with a valid process for
   ///     optional tuning Objective-C runtime support. Can be NULL.
@@ -77,7 +77,7 @@ public:
   /// \return
   ///     The number of errors encountered during parsing.  0 means
   ///     success.
-  unsigned Parse(DiagnosticManager &diagnostic_manager) override;
+  unsigned Parse(DiagnosticManager &diagnostic_manager);
 
   bool RewriteExpression(DiagnosticManager &diagnostic_manager) override;
 
@@ -99,15 +99,6 @@ public:
   /// \param[in] exe_ctx
   ///     The execution context to write the function into.
   ///
-  /// \param[out] evaluated_statically
-  ///     Set to true if the expression could be interpreted statically;
-  ///     untouched otherwise.
-  ///
-  /// \param[out] const_result
-  ///     If the result of the expression is constant, and the
-  ///     expression has no side effects, this is set to the result of the
-  ///     expression.
-  ///
   /// \param[in] execution_policy
   ///     Determines whether the expression must be JIT-compiled, must be
   ///     evaluated statically, or whether this decision may be made
diff --git a/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionSourceCode.cpp b/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionSourceCode.cpp
index 21cb33402e7f..7ebb5fee1ec6 100644
--- a/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionSourceCode.cpp
+++ b/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionSourceCode.cpp
@@ -315,12 +315,10 @@ bool ClangExpressionSourceCode::GetText(
       }
     }
 
-    if (ClangModulesDeclVendor *decl_vendor =
-            target->GetClangModulesDeclVendor()) {
-      ClangPersistentVariables *persistent_vars =
-          llvm::cast<ClangPersistentVariables>(
-              target->GetPersistentExpressionStateForLanguage(
-                  lldb::eLanguageTypeC));
+    ClangModulesDeclVendor *decl_vendor = target->GetClangModulesDeclVendor();
+    auto *persistent_vars = llvm::cast<ClangPersistentVariables>(
+        target->GetPersistentExpressionStateForLanguage(lldb::eLanguageTypeC));
+    if (decl_vendor && persistent_vars) {
       const ClangModulesDeclVendor::ModuleVector &hand_imported_modules =
           persistent_vars->GetHandLoadedClangModules();
       ClangModulesDeclVendor::ModuleVector modules_for_macros;
diff --git a/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionVariable.h b/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionVariable.h
index eb7f74f20a20..0e6de28ee4df 100644
--- a/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionVariable.h
+++ b/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionVariable.h
@@ -74,9 +74,6 @@ public:
 
   /// Finds a variable by NamedDecl in the list.
   ///
-  /// \param[in] name
-  ///     The name of the requested variable.
-  ///
   /// \return
   ///     The variable requested, or NULL if that variable is not in the list.
   static ClangExpressionVariable *
diff --git a/lldb/source/Plugins/ExpressionParser/Clang/ClangFunctionCaller.cpp b/lldb/source/Plugins/ExpressionParser/Clang/ClangFunctionCaller.cpp
index 8fbfa6e47578..7f7c0a97f538 100644
--- a/lldb/source/Plugins/ExpressionParser/Clang/ClangFunctionCaller.cpp
+++ b/lldb/source/Plugins/ExpressionParser/Clang/ClangFunctionCaller.cpp
@@ -42,6 +42,8 @@
 
 using namespace lldb_private;
 
+char ClangFunctionCaller::ID;
+
 // ClangFunctionCaller constructor
 ClangFunctionCaller::ClangFunctionCaller(ExecutionContextScope &exe_scope,
                                          const CompilerType &return_type,
@@ -186,10 +188,10 @@ ClangFunctionCaller::CompileFunction(lldb::ThreadSP thread_to_use_sp,
   lldb::ProcessSP jit_process_sp(m_jit_process_wp.lock());
   if (jit_process_sp) {
     const bool generate_debug_info = true;
-    m_parser.reset(new ClangExpressionParser(jit_process_sp.get(), *this,
-                                             generate_debug_info));
-
-    num_errors = m_parser->Parse(diagnostic_manager);
+    auto *clang_parser = new ClangExpressionParser(jit_process_sp.get(), *this,
+                                                   generate_debug_info);
+    num_errors = clang_parser->Parse(diagnostic_manager);
+    m_parser.reset(clang_parser);
   } else {
     diagnostic_manager.PutString(eDiagnosticSeverityError,
                                  "no process - unable to inject function");
diff --git a/lldb/source/Plugins/ExpressionParser/Clang/ClangFunctionCaller.h b/lldb/source/Plugins/ExpressionParser/Clang/ClangFunctionCaller.h
index 24f6f2eb91b3..150a913152d0 100644
--- a/lldb/source/Plugins/ExpressionParser/Clang/ClangFunctionCaller.h
+++ b/lldb/source/Plugins/ExpressionParser/Clang/ClangFunctionCaller.h
@@ -59,11 +59,6 @@ class ClangExpressionParser;
 class ClangFunctionCaller : public FunctionCaller {
   friend class ASTStructExtractor;
 
-  /// LLVM-style RTTI support.
-  static bool classof(const Expression *E) {
-    return E->getKind() == eKindClangFunctionCaller;
-  }
-
   class ClangFunctionCallerHelper : public ClangExpressionHelper {
   public:
     ClangFunctionCallerHelper(ClangFunctionCaller &owner) : m_owner(owner) {}
@@ -91,18 +86,23 @@ class ClangFunctionCaller : public FunctionCaller {
                                                             ///layout.
   };
 
+  // LLVM RTTI support
+  static char ID;
+
 public:
+  bool isA(const void *ClassID) const override {
+    return ClassID == &ID || FunctionCaller::isA(ClassID);
+  }
+  static bool classof(const Expression *obj) { return obj->isA(&ID); }
+
   /// Constructor
   ///
   /// \param[in] exe_scope
   ///     An execution context scope that gets us at least a target and
   ///     process.
   ///
-  /// \param[in] ast_context
-  ///     The AST context to evaluate argument types in.
-  ///
-  /// \param[in] return_qualtype
-  ///     An opaque Clang QualType for the function result.  Should be
+  /// \param[in] return_type
+  ///     A compiler type for the function result.  Should be
   ///     defined in ast_context.
   ///
   /// \param[in] function_address
diff --git a/lldb/source/Plugins/ExpressionParser/Clang/ClangModulesDeclVendor.cpp b/lldb/source/Plugins/ExpressionParser/Clang/ClangModulesDeclVendor.cpp
index f3df589d7311..0696c669f2e2 100644
--- a/lldb/source/Plugins/ExpressionParser/Clang/ClangModulesDeclVendor.cpp
+++ b/lldb/source/Plugins/ExpressionParser/Clang/ClangModulesDeclVendor.cpp
@@ -80,12 +80,10 @@ public:
                                 Stream &error_stream) override;
 
   uint32_t FindDecls(ConstString name, bool append, uint32_t max_matches,
-                     std::vector<clang::NamedDecl *> &decls) override;
+                     std::vector<CompilerDecl> &decls) override;
 
   void ForEachMacro(const ModuleVector &modules,
                     std::function<bool(const std::string &)> handler) override;
-
-  clang::ExternalASTMerger::ImporterSource GetImporterSource() override;
 private:
   void
   ReportModuleExportsHelper(std::set<ClangModulesDeclVendor::ModuleID> &exports,
@@ -110,7 +108,6 @@ private:
   typedef std::set<ModuleID> ImportedModuleSet;
   ImportedModuleMap m_imported_modules;
   ImportedModuleSet m_user_imported_modules;
-  const clang::ExternalASTMerger::OriginMap m_origin_map;
   // We assume that every ASTContext has an ClangASTContext, so we also store
   // a custom ClangASTContext for our internal ASTContext.
   std::unique_ptr<ClangASTContext> m_ast_context;
@@ -160,7 +157,7 @@ ClangModulesDeclVendorImpl::ClangModulesDeclVendorImpl(
     : m_diagnostics_engine(std::move(diagnostics_engine)),
       m_compiler_invocation(std::move(compiler_invocation)),
       m_compiler_instance(std::move(compiler_instance)),
-      m_parser(std::move(parser)), m_origin_map() {
+      m_parser(std::move(parser)) {
 
   // Initialize our ClangASTContext.
   m_ast_context.reset(new ClangASTContext(m_compiler_instance->getASTContext()));
@@ -359,7 +356,7 @@ bool ClangModulesDeclVendorImpl::AddModulesForCompileUnit(
 uint32_t
 ClangModulesDeclVendorImpl::FindDecls(ConstString name, bool append,
                                       uint32_t max_matches,
-                                      std::vector<clang::NamedDecl *> &decls) {
+                                      std::vector<CompilerDecl> &decls) {
   if (!m_enabled) {
     return 0;
   }
@@ -385,7 +382,7 @@ ClangModulesDeclVendorImpl::FindDecls(ConstString name, bool append,
     if (num_matches >= max_matches)
       return num_matches;
 
-    decls.push_back(named_decl);
+    decls.push_back(CompilerDecl(m_ast_context.get(), named_decl));
     ++num_matches;
   }
 
@@ -569,13 +566,6 @@ ClangModulesDeclVendorImpl::DoGetModule(clang::ModuleIdPath path,
                                          is_inclusion_directive);
 }
 
-clang::ExternalASTMerger::ImporterSource
-ClangModulesDeclVendorImpl::GetImporterSource() {
-  return clang::ExternalASTMerger::ImporterSource(
-      m_compiler_instance->getASTContext(),
-      m_compiler_instance->getFileManager(), m_origin_map);
-}
-
 static const char *ModuleImportBufferName = "LLDBModulesMemoryBuffer";
 
 lldb_private::ClangModulesDeclVendor *
@@ -704,7 +694,7 @@ ClangModulesDeclVendor::Create(Target &target) {
 
   instance->getPreprocessor().enableIncrementalProcessing();
 
-  instance->createModuleManager();
+  instance->createASTReader();
 
   instance->createSema(action->getTranslationUnitKind(), nullptr);
 
diff --git a/lldb/source/Plugins/ExpressionParser/Clang/ClangPersistentVariables.cpp b/lldb/source/Plugins/ExpressionParser/Clang/ClangPersistentVariables.cpp
index 24dd705e37b1..41d62a462ab4 100644
--- a/lldb/source/Plugins/ExpressionParser/Clang/ClangPersistentVariables.cpp
+++ b/lldb/source/Plugins/ExpressionParser/Clang/ClangPersistentVariables.cpp
@@ -67,39 +67,35 @@ void ClangPersistentVariables::RemovePersistentVariable(
 llvm::Optional<CompilerType>
 ClangPersistentVariables::GetCompilerTypeFromPersistentDecl(
     ConstString type_name) {
-  CompilerType compiler_type;
-  if (clang::TypeDecl *tdecl = llvm::dyn_cast_or_null<clang::TypeDecl>(
-          GetPersistentDecl(type_name))) {
-    compiler_type.SetCompilerType(
-        ClangASTContext::GetASTContext(&tdecl->getASTContext()),
-        reinterpret_cast<lldb::opaque_compiler_type_t>(
-            const_cast<clang::Type *>(tdecl->getTypeForDecl())));
-    return compiler_type;
+  PersistentDecl p = m_persistent_decls.lookup(type_name.GetCString());
+
+  if (p.m_decl == nullptr)
+    return llvm::None;
+
+  if (clang::TypeDecl *tdecl = llvm::dyn_cast<clang::TypeDecl>(p.m_decl)) {
+    opaque_compiler_type_t t = static_cast<opaque_compiler_type_t>(
+        const_cast<clang::Type *>(tdecl->getTypeForDecl()));
+    return CompilerType(p.m_context, t);
   }
   return llvm::None;
 }
 
 void ClangPersistentVariables::RegisterPersistentDecl(ConstString name,
-                                                      clang::NamedDecl *decl) {
-  m_persistent_decls.insert(
-      std::pair<const char *, clang::NamedDecl *>(name.GetCString(), decl));
+                                                      clang::NamedDecl *decl,
+                                                      ClangASTContext *ctx) {
+  PersistentDecl p = {decl, ctx};
+  m_persistent_decls.insert(std::make_pair(name.GetCString(), p));
 
   if (clang::EnumDecl *enum_decl = llvm::dyn_cast<clang::EnumDecl>(decl)) {
     for (clang::EnumConstantDecl *enumerator_decl : enum_decl->enumerators()) {
-      m_persistent_decls.insert(std::pair<const char *, clang::NamedDecl *>(
-          ConstString(enumerator_decl->getNameAsString()).GetCString(),
-          enumerator_decl));
+      p = {enumerator_decl, ctx};
+      m_persistent_decls.insert(std::make_pair(
+          ConstString(enumerator_decl->getNameAsString()).GetCString(), p));
     }
   }
 }
 
 clang::NamedDecl *
 ClangPersistentVariables::GetPersistentDecl(ConstString name) {
-  PersistentDeclMap::const_iterator i =
-      m_persistent_decls.find(name.GetCString());
-
-  if (i == m_persistent_decls.end())
-    return nullptr;
-  else
-    return i->second;
+  return m_persistent_decls.lookup(name.GetCString()).m_decl;
 }
diff --git a/lldb/source/Plugins/ExpressionParser/Clang/ClangPersistentVariables.h b/lldb/source/Plugins/ExpressionParser/Clang/ClangPersistentVariables.h
index 95e6c3ac963d..434196b35fd5 100644
--- a/lldb/source/Plugins/ExpressionParser/Clang/ClangPersistentVariables.h
+++ b/lldb/source/Plugins/ExpressionParser/Clang/ClangPersistentVariables.h
@@ -62,7 +62,8 @@ public:
   llvm::Optional<CompilerType>
   GetCompilerTypeFromPersistentDecl(ConstString type_name) override;
 
-  void RegisterPersistentDecl(ConstString name, clang::NamedDecl *decl);
+  void RegisterPersistentDecl(ConstString name, clang::NamedDecl *decl,
+                              ClangASTContext *ctx);
 
   clang::NamedDecl *GetPersistentDecl(ConstString name);
 
@@ -80,7 +81,14 @@ private:
   // The counter used by GetNextPersistentVariableName
   uint32_t m_next_persistent_variable_id = 0;
 
-  typedef llvm::DenseMap<const char *, clang::NamedDecl *> PersistentDeclMap;
+  struct PersistentDecl {
+    /// The persistent decl.
+    clang::NamedDecl *m_decl = nullptr;
+    /// The ClangASTContext for the ASTContext of m_decl.
+    ClangASTContext *m_context = nullptr;
+  };
+
+  typedef llvm::DenseMap<const char *, PersistentDecl> PersistentDeclMap;
   PersistentDeclMap
       m_persistent_decls; ///< Persistent entities declared by the user.
 
diff --git a/lldb/source/Plugins/ExpressionParser/Clang/ClangUserExpression.cpp b/lldb/source/Plugins/ExpressionParser/Clang/ClangUserExpression.cpp
index da1ca785635c..6698797617a3 100644
--- a/lldb/source/Plugins/ExpressionParser/Clang/ClangUserExpression.cpp
+++ b/lldb/source/Plugins/ExpressionParser/Clang/ClangUserExpression.cpp
@@ -38,10 +38,11 @@
 #include "lldb/Host/HostInfo.h"
 #include "lldb/Symbol/Block.h"
 #include "lldb/Symbol/ClangASTContext.h"
-#include "lldb/Symbol/ClangExternalASTSourceCommon.h"
+#include "lldb/Symbol/ClangASTMetadata.h"
 #include "lldb/Symbol/CompileUnit.h"
 #include "lldb/Symbol/Function.h"
 #include "lldb/Symbol/ObjectFile.h"
+#include "lldb/Symbol/SymbolFile.h"
 #include "lldb/Symbol/SymbolVendor.h"
 #include "lldb/Symbol/Type.h"
 #include "lldb/Symbol/VariableList.h"
@@ -62,13 +63,15 @@
 
 using namespace lldb_private;
 
+char ClangUserExpression::ID;
+
 ClangUserExpression::ClangUserExpression(
     ExecutionContextScope &exe_scope, llvm::StringRef expr,
     llvm::StringRef prefix, lldb::LanguageType language,
     ResultType desired_type, const EvaluateExpressionOptions &options,
     ValueObject *ctx_obj)
     : LLVMUserExpression(exe_scope, expr, prefix, language, desired_type,
-                         options, eKindClangUserExpression),
+                         options),
       m_type_system_helper(*m_target_wp.lock(), options.GetExecutionPolicy() ==
                                                     eExecutionPolicyTopLevel),
       m_result_delegate(exe_scope.CalculateTarget()), m_ctx_obj(ctx_obj) {
@@ -347,11 +350,12 @@ bool ClangUserExpression::SetupPersistentState(DiagnosticManager &diagnostic_man
 static void SetupDeclVendor(ExecutionContext &exe_ctx, Target *target) {
   if (ClangModulesDeclVendor *decl_vendor =
           target->GetClangModulesDeclVendor()) {
+    auto *persistent_state = llvm::cast<ClangPersistentVariables>(
+        target->GetPersistentExpressionStateForLanguage(lldb::eLanguageTypeC));
+    if (!persistent_state)
+      return;
     const ClangModulesDeclVendor::ModuleVector &hand_imported_modules =
-        llvm::cast<ClangPersistentVariables>(
-            target->GetPersistentExpressionStateForLanguage(
-                lldb::eLanguageTypeC))
-            ->GetHandLoadedClangModules();
+        persistent_state->GetHandLoadedClangModules();
     ClangModulesDeclVendor::ModuleVector modules_for_macros;
 
     for (ClangModulesDeclVendor::ModuleID module : hand_imported_modules) {
@@ -476,15 +480,18 @@ CppModuleConfiguration GetModuleConfig(lldb::LanguageType language,
     files.AppendIfUnique(f);
   // We also need to look at external modules in the case of -gmodules as they
   // contain the support files for libc++ and the C library.
-  sc.comp_unit->ForEachExternalModule([&files](lldb::ModuleSP module) {
-    for (std::size_t i = 0; i < module->GetNumCompileUnits(); ++i) {
-      const FileSpecList &support_files =
-          module->GetCompileUnitAtIndex(i)->GetSupportFiles();
-      for (const FileSpec &f : support_files) {
-        files.AppendIfUnique(f);
-      }
-    }
-  });
+  llvm::DenseSet<SymbolFile *> visited_symbol_files;
+  sc.comp_unit->ForEachExternalModule(
+      visited_symbol_files, [&files](Module &module) {
+        for (std::size_t i = 0; i < module.GetNumCompileUnits(); ++i) {
+          const FileSpecList &support_files =
+              module.GetCompileUnitAtIndex(i)->GetSupportFiles();
+          for (const FileSpec &f : support_files) {
+            files.AppendIfUnique(f);
+          }
+        }
+        return false;
+      });
 
   LLDB_LOG(log, "[C++ module config] Found {0} support files to analyze",
            files.GetSize());
@@ -576,7 +583,7 @@ bool ClangUserExpression::Parse(DiagnosticManager &diagnostic_manager,
 
   auto on_exit = llvm::make_scope_exit([this]() { ResetDeclMap(); });
 
-  if (!DeclMap()->WillParse(exe_ctx, m_materializer_up.get())) {
+  if (!DeclMap()->WillParse(exe_ctx, GetMaterializer())) {
     diagnostic_manager.PutString(
         eDiagnosticSeverityError,
         "current process state is unsuitable for expression parsing");
@@ -676,10 +683,12 @@ bool ClangUserExpression::Parse(DiagnosticManager &diagnostic_manager,
       register_execution_unit = true;
     }
 
-    if (register_execution_unit)
-      exe_ctx.GetTargetPtr()
-          ->GetPersistentExpressionStateForLanguage(m_language)
-          ->RegisterExecutionUnit(m_execution_unit_sp);
+    if (register_execution_unit) {
+      if (auto *persistent_state =
+              exe_ctx.GetTargetPtr()->GetPersistentExpressionStateForLanguage(
+                  m_language))
+        persistent_state->RegisterExecutionUnit(m_execution_unit_sp);
+    }
   }
 
   if (generate_debug_info) {
@@ -764,7 +773,7 @@ bool ClangUserExpression::Complete(ExecutionContext &exe_ctx,
 
   auto on_exit = llvm::make_scope_exit([this]() { ResetDeclMap(); });
 
-  if (!DeclMap()->WillParse(exe_ctx, m_materializer_up.get())) {
+  if (!DeclMap()->WillParse(exe_ctx, GetMaterializer())) {
     diagnostic_manager.PutString(
         eDiagnosticSeverityError,
         "current process state is unsuitable for expression parsing");
@@ -887,9 +896,9 @@ void ClangUserExpression::ClangUserExpressionHelper::ResetDeclMap(
     Materializer::PersistentVariableDelegate &delegate,
     bool keep_result_in_memory,
     ValueObject *ctx_obj) {
-  m_expr_decl_map_up.reset(
-      new ClangExpressionDeclMap(keep_result_in_memory, &delegate, exe_ctx,
-                                 ctx_obj));
+  m_expr_decl_map_up.reset(new ClangExpressionDeclMap(
+      keep_result_in_memory, &delegate, exe_ctx.GetTargetSP(),
+      exe_ctx.GetTargetRef().GetClangASTImporter(), ctx_obj));
 }
 
 clang::ASTConsumer *
diff --git a/lldb/source/Plugins/ExpressionParser/Clang/ClangUserExpression.h b/lldb/source/Plugins/ExpressionParser/Clang/ClangUserExpression.h
index d94f9cc5e066..00cbffa7fd6f 100644
--- a/lldb/source/Plugins/ExpressionParser/Clang/ClangUserExpression.h
+++ b/lldb/source/Plugins/ExpressionParser/Clang/ClangUserExpression.h
@@ -38,11 +38,14 @@ namespace lldb_private {
 /// the objects needed to parse and interpret or JIT an expression.  It uses
 /// the Clang parser to produce LLVM IR from the expression.
 class ClangUserExpression : public LLVMUserExpression {
+  // LLVM RTTI support
+  static char ID;
+
 public:
-  /// LLVM-style RTTI support.
-  static bool classof(const Expression *E) {
-    return E->getKind() == eKindClangUserExpression;
+  bool isA(const void *ClassID) const override {
+    return ClassID == &ID || LLVMUserExpression::isA(ClassID);
   }
+  static bool classof(const Expression *obj) { return obj->isA(&ID); }
 
   enum { kDefaultTimeout = 500000u };
 
@@ -93,7 +96,7 @@ public:
   /// \param[in] expr
   ///     The expression to parse.
   ///
-  /// \param[in] expr_prefix
+  /// \param[in] prefix
   ///     If non-NULL, a C string containing translation-unit level
   ///     definitions to be included when the expression is parsed.
   ///
diff --git a/lldb/source/Plugins/ExpressionParser/Clang/ClangUtilityFunction.cpp b/lldb/source/Plugins/ExpressionParser/Clang/ClangUtilityFunction.cpp
index 564c62c6a2c6..199e4898e118 100644
--- a/lldb/source/Plugins/ExpressionParser/Clang/ClangUtilityFunction.cpp
+++ b/lldb/source/Plugins/ExpressionParser/Clang/ClangUtilityFunction.cpp
@@ -31,6 +31,8 @@
 
 using namespace lldb_private;
 
+char ClangUtilityFunction::ID;
+
 /// Constructor
 ///
 /// \param[in] text
@@ -40,7 +42,7 @@ using namespace lldb_private;
 ///     The name of the function, as used in the text.
 ClangUtilityFunction::ClangUtilityFunction(ExecutionContextScope &exe_scope,
                                            const char *text, const char *name)
-    : UtilityFunction(exe_scope, text, name, eKindClangUtilityFunction) {
+    : UtilityFunction(exe_scope, text, name) {
   m_function_text.assign(ClangExpressionSourceCode::g_expression_prefix);
   if (text && text[0])
     m_function_text.append(text);
@@ -157,7 +159,7 @@ bool ClangUtilityFunction::Install(DiagnosticManager &diagnostic_manager,
 
 void ClangUtilityFunction::ClangUtilityFunctionHelper::ResetDeclMap(
     ExecutionContext &exe_ctx, bool keep_result_in_memory) {
-  m_expr_decl_map_up.reset(
-      new ClangExpressionDeclMap(keep_result_in_memory, nullptr, exe_ctx,
-                                 nullptr));
+  m_expr_decl_map_up.reset(new ClangExpressionDeclMap(
+      keep_result_in_memory, nullptr, exe_ctx.GetTargetSP(),
+      exe_ctx.GetTargetRef().GetClangASTImporter(), nullptr));
 }
diff --git a/lldb/source/Plugins/ExpressionParser/Clang/ClangUtilityFunction.h b/lldb/source/Plugins/ExpressionParser/Clang/ClangUtilityFunction.h
index 70ebb2f3ad8a..9efaa0254c3e 100644
--- a/lldb/source/Plugins/ExpressionParser/Clang/ClangUtilityFunction.h
+++ b/lldb/source/Plugins/ExpressionParser/Clang/ClangUtilityFunction.h
@@ -33,11 +33,14 @@ namespace lldb_private {
 /// simply provide a way to push a function into the target for the debugger
 /// to call later on.
 class ClangUtilityFunction : public UtilityFunction {
+  // LLVM RTTI support
+  static char ID;
+
 public:
-  /// LLVM-style RTTI support.
-  static bool classof(const Expression *E) {
-    return E->getKind() == eKindClangUtilityFunction;
+  bool isA(const void *ClassID) const override {
+    return ClassID == &ID || UtilityFunction::isA(ClassID);
   }
+  static bool classof(const Expression *obj) { return obj->isA(&ID); }
 
   class ClangUtilityFunctionHelper : public ClangExpressionHelper {
   public:
diff --git a/lldb/source/Plugins/ExpressionParser/Clang/IRDynamicChecks.h b/lldb/source/Plugins/ExpressionParser/Clang/IRDynamicChecks.h
index 60c0691b21c1..5b9c8007ab76 100644
--- a/lldb/source/Plugins/ExpressionParser/Clang/IRDynamicChecks.h
+++ b/lldb/source/Plugins/ExpressionParser/Clang/IRDynamicChecks.h
@@ -76,10 +76,6 @@ public:
   ///
   /// \param[in] func_name
   ///     The name of the function to prepare for execution in the target.
-  ///
-  /// \param[in] decl_map
-  ///     The mapping used to look up entities in the target process. In
-  ///     this case, used to find objc_msgSend
   IRDynamicChecks(ClangDynamicCheckerFunctions &checker_functions,
                   const char *func_name = "$__lldb_expr");
 
diff --git a/lldb/source/Plugins/ExpressionParser/Clang/IRForTarget.cpp b/lldb/source/Plugins/ExpressionParser/Clang/IRForTarget.cpp
index 4e871f7d6a44..103a7ee46f35 100644
--- a/lldb/source/Plugins/ExpressionParser/Clang/IRForTarget.cpp
+++ b/lldb/source/Plugins/ExpressionParser/Clang/IRForTarget.cpp
@@ -355,7 +355,7 @@ bool IRForTarget::CreateResultVariable(llvm::Function &llvm_function) {
 
   ConstantInt *new_constant_int =
       ConstantInt::get(llvm::Type::getInt64Ty(m_module->getContext()),
-                       reinterpret_cast<uint64_t>(result_decl), false);
+                       reinterpret_cast<uintptr_t>(result_decl), false);
 
   llvm::Metadata *values[2];
   values[0] = ConstantAsMetadata::get(new_result_global);
diff --git a/lldb/source/Plugins/ExpressionParser/Clang/IRForTarget.h b/lldb/source/Plugins/ExpressionParser/Clang/IRForTarget.h
index 893620f7f8e0..262e8ee0c06c 100644
--- a/lldb/source/Plugins/ExpressionParser/Clang/IRForTarget.h
+++ b/lldb/source/Plugins/ExpressionParser/Clang/IRForTarget.h
@@ -71,15 +71,6 @@ public:
   ///     variables) should be resolved.  If not, only external functions
   ///     are resolved.
   ///
-  /// \param[in] execution_policy
-  ///     Determines whether an IR interpreter can be used to statically
-  ///     evaluate the expression.
-  ///
-  /// \param[in] const_result
-  ///     This variable is populated with the statically-computed result
-  ///     of the function, if it has no side-effects and the result can
-  ///     be computed statically.
-  ///
   /// \param[in] execution_unit
   ///     The holder for raw data associated with the expression.
   ///
@@ -105,10 +96,6 @@ public:
   ///     $__lldb_expr, and that function is passed to the passes one by
   ///     one.
   ///
-  /// \param[in] interpreter_error
-  ///     An error.  If the expression fails to be interpreted, this error
-  ///     is set to a reason why.
-  ///
   /// \return
   ///     True on success; false otherwise
   bool runOnModule(llvm::Module &llvm_module) override;
@@ -142,9 +129,6 @@ private:
 
   /// The top-level pass implementation
   ///
-  /// \param[in] llvm_module
-  ///     The module currently being processed.
-  ///
   /// \param[in] llvm_function
   ///     The function currently being processed.
   ///
@@ -184,12 +168,12 @@ private:
   /// Find the NamedDecl corresponding to a Value.  This interface is exposed
   /// for the IR interpreter.
   ///
+  /// \param[in] global_val
+  ///     The global entity to search for
+  ///
   /// \param[in] module
   ///     The module containing metadata to search
   ///
-  /// \param[in] global
-  ///     The global entity to search for
-  ///
   /// \return
   ///     The corresponding variable declaration
 public:
@@ -287,7 +271,7 @@ private:
 
   /// Replace a single old-style class reference
   ///
-  /// \param[in] selector_load
+  /// \param[in] class_load
   ///     The load of the statically-allocated selector.
   ///
   /// \return
@@ -362,7 +346,7 @@ private:
 
   /// Handle all the arguments to a function call
   ///
-  /// \param[in] C
+  /// \param[in] call_inst
   ///     The call instruction.
   ///
   /// \return
@@ -381,8 +365,8 @@ private:
   /// Remove calls to __cxa_atexit, which should never be generated by
   /// expressions.
   ///
-  /// \param[in] call_inst
-  ///     The call instruction.
+  /// \param[in] basic_block
+  ///     The basic block currently being processed.
   ///
   /// \return
   ///     True if the scan was successful; false if some operation
@@ -391,7 +375,7 @@ private:
 
   /// The top-level pass implementation
   ///
-  /// \param[in] basic_block
+  /// \param[in] llvm_function
   ///     The function currently being processed.
   ///
   /// \return
@@ -474,28 +458,9 @@ private:
                             ///pointer (see comments in
                             /// ASTResultSynthesizer::SynthesizeBodyResult)
 
-  llvm::GlobalVariable *m_reloc_placeholder; ///< A placeholder that will be
-                                             ///replaced by a pointer to the
-                                             ///final
-  /// location of the static allocation.
-
-  /// UnfoldConstant operates on a constant [Old] which has just been replaced
-  /// with a value [New].  We assume that new_value has been properly placed
-  /// early in the function, in front of the first instruction in the entry
-  /// basic block [FirstEntryInstruction].
-  ///
-  /// UnfoldConstant reads through the uses of Old and replaces Old in those
-  /// uses with New.  Where those uses are constants, the function generates
-  /// new instructions to compute the result of the new, non-constant
-  /// expression and places them before FirstEntryInstruction.  These
-  /// instructions replace the constant uses, so UnfoldConstant calls itself
-  /// recursively for those.
-  ///
-  /// \param[in] llvm_function
-  ///     The function currently being processed.
-  ///
-  /// \return
-  ///     True on success; false otherwise
+  /// A placeholder that will be replaced by a pointer to the final location of
+  /// the static allocation.
+  llvm::GlobalVariable *m_reloc_placeholder;
 
   class FunctionValueCache {
   public:
@@ -513,6 +478,20 @@ private:
 
   FunctionValueCache m_entry_instruction_finder;
 
+  /// UnfoldConstant operates on a constant [Old] which has just been replaced
+  /// with a value [New].  We assume that new_value has been properly placed
+  /// early in the function, in front of the first instruction in the entry
+  /// basic block [FirstEntryInstruction].
+  ///
+  /// UnfoldConstant reads through the uses of Old and replaces Old in those
+  /// uses with New.  Where those uses are constants, the function generates
+  /// new instructions to compute the result of the new, non-constant
+  /// expression and places them before FirstEntryInstruction.  These
+  /// instructions replace the constant uses, so UnfoldConstant calls itself
+  /// recursively for those.
+  ///
+  /// \return
+  ///     True on success; false otherwise
   static bool UnfoldConstant(llvm::Constant *old_constant,
                              llvm::Function *llvm_function,
                              FunctionValueCache &value_maker,
@@ -522,9 +501,6 @@ private:
   /// Commit the allocation in m_data_allocator and use its final location to
   /// replace m_reloc_placeholder.
   ///
-  /// \param[in] module
-  ///     The module that m_data_allocator resides in
-  ///
   /// \return
   ///     True on success; false otherwise
   bool CompleteDataAllocation();
diff --git a/lldb/source/Plugins/Instruction/ARM/EmulateInstructionARM.cpp b/lldb/source/Plugins/Instruction/ARM/EmulateInstructionARM.cpp
index 19a987b0f004..ff142e6f35ff 100644
--- a/lldb/source/Plugins/Instruction/ARM/EmulateInstructionARM.cpp
+++ b/lldb/source/Plugins/Instruction/ARM/EmulateInstructionARM.cpp
@@ -850,6 +850,7 @@ uint32_t EmulateInstructionARM::GetFramePointerRegisterNumber() const {
 
   /* On Apple iOS et al, the frame pointer register is always r7.
    * Typically on other ARM systems, thumb code uses r7; arm code uses r11.
+   * Windows on ARM, which is in thumb mode, uses r11 though.
    */
 
   uint32_t fp_regnum = 11;
@@ -857,7 +858,7 @@ uint32_t EmulateInstructionARM::GetFramePointerRegisterNumber() const {
   if (is_apple)
     fp_regnum = 7;
 
-  if (m_opcode_mode == eModeThumb)
+  if (m_opcode_mode == eModeThumb && !m_arch.GetTriple().isOSWindows())
     fp_regnum = 7;
 
   return fp_regnum;
@@ -879,6 +880,7 @@ uint32_t EmulateInstructionARM::GetFramePointerDWARFRegisterNumber() const {
 
   /* On Apple iOS et al, the frame pointer register is always r7.
    * Typically on other ARM systems, thumb code uses r7; arm code uses r11.
+   * Windows on ARM, which is in thumb mode, uses r11 though.
    */
 
   uint32_t fp_regnum = dwarf_r11;
@@ -886,7 +888,7 @@ uint32_t EmulateInstructionARM::GetFramePointerDWARFRegisterNumber() const {
   if (is_apple)
     fp_regnum = dwarf_r7;
 
-  if (m_opcode_mode == eModeThumb)
+  if (m_opcode_mode == eModeThumb && !m_arch.GetTriple().isOSWindows())
     fp_regnum = dwarf_r7;
 
   return fp_regnum;
@@ -1343,6 +1345,8 @@ bool EmulateInstructionARM::EmulateMOVRdRm(const uint32_t opcode,
     EmulateInstruction::Context context;
     if (Rd == 13)
       context.type = EmulateInstruction::eContextAdjustStackPointer;
+    else if (Rd == GetFramePointerRegisterNumber() && Rm == 13)
+      context.type = EmulateInstruction::eContextSetFramePointer;
     else
       context.type = EmulateInstruction::eContextRegisterPlusOffset;
     RegisterInfo dwarf_reg;
diff --git a/lldb/source/Plugins/Instruction/MIPS/EmulateInstructionMIPS.cpp b/lldb/source/Plugins/Instruction/MIPS/EmulateInstructionMIPS.cpp
index 21b6296745bd..b55eeb0eaf46 100644
--- a/lldb/source/Plugins/Instruction/MIPS/EmulateInstructionMIPS.cpp
+++ b/lldb/source/Plugins/Instruction/MIPS/EmulateInstructionMIPS.cpp
@@ -28,6 +28,7 @@
 #include "llvm/MC/MCInstrInfo.h"
 #include "llvm/MC/MCRegisterInfo.h"
 #include "llvm/MC/MCSubtargetInfo.h"
+#include "llvm/MC/MCTargetOptions.h"
 #include "llvm/Support/TargetRegistry.h"
 #include "llvm/Support/TargetSelect.h"
 
@@ -149,7 +150,9 @@ EmulateInstructionMIPS::EmulateInstructionMIPS(
   m_insn_info.reset(target->createMCInstrInfo());
   assert(m_insn_info.get());
 
-  m_asm_info.reset(target->createMCAsmInfo(*m_reg_info, triple.getTriple()));
+  llvm::MCTargetOptions MCOptions;
+  m_asm_info.reset(
+      target->createMCAsmInfo(*m_reg_info, triple.getTriple(), MCOptions));
   m_subtype_info.reset(
       target->createMCSubtargetInfo(triple.getTriple(), cpu, features));
   assert(m_asm_info.get() && m_subtype_info.get());
@@ -978,13 +981,11 @@ EmulateInstructionMIPS::GetSizeOfInstruction(lldb_private::DataExtractor &data,
   llvm::ArrayRef<uint8_t> raw_insn(data.GetDataStart(), data.GetByteSize());
 
   if (m_use_alt_disaasm)
-    decode_status =
-        m_alt_disasm->getInstruction(mc_insn, next_inst_size, raw_insn,
-                                     inst_addr, llvm::nulls(), llvm::nulls());
+    decode_status = m_alt_disasm->getInstruction(
+        mc_insn, next_inst_size, raw_insn, inst_addr, llvm::nulls());
   else
-    decode_status =
-        m_disasm->getInstruction(mc_insn, next_inst_size, raw_insn, inst_addr,
-                                 llvm::nulls(), llvm::nulls());
+    decode_status = m_disasm->getInstruction(mc_insn, next_inst_size, raw_insn,
+                                             inst_addr, llvm::nulls());
 
   if (decode_status != llvm::MCDisassembler::Success)
     return false;
@@ -1067,11 +1068,11 @@ bool EmulateInstructionMIPS::EvaluateInstruction(uint32_t evaluate_options) {
     llvm::MCDisassembler::DecodeStatus decode_status;
     llvm::ArrayRef<uint8_t> raw_insn(data.GetDataStart(), data.GetByteSize());
     if (m_use_alt_disaasm)
-      decode_status = m_alt_disasm->getInstruction(
-          mc_insn, insn_size, raw_insn, m_addr, llvm::nulls(), llvm::nulls());
+      decode_status = m_alt_disasm->getInstruction(mc_insn, insn_size, raw_insn,
+                                                   m_addr, llvm::nulls());
     else
-      decode_status = m_disasm->getInstruction(
-          mc_insn, insn_size, raw_insn, m_addr, llvm::nulls(), llvm::nulls());
+      decode_status = m_disasm->getInstruction(mc_insn, insn_size, raw_insn,
+                                               m_addr, llvm::nulls());
 
     if (decode_status != llvm::MCDisassembler::Success)
       return false;
diff --git a/lldb/source/Plugins/Instruction/MIPS64/EmulateInstructionMIPS64.cpp b/lldb/source/Plugins/Instruction/MIPS64/EmulateInstructionMIPS64.cpp
index 5fabbeb756cc..3baf942bc17f 100644
--- a/lldb/source/Plugins/Instruction/MIPS64/EmulateInstructionMIPS64.cpp
+++ b/lldb/source/Plugins/Instruction/MIPS64/EmulateInstructionMIPS64.cpp
@@ -28,6 +28,7 @@
 #include "llvm/MC/MCInstrInfo.h"
 #include "llvm/MC/MCRegisterInfo.h"
 #include "llvm/MC/MCSubtargetInfo.h"
+#include "llvm/MC/MCTargetOptions.h"
 #include "llvm/Support/TargetRegistry.h"
 #include "llvm/Support/TargetSelect.h"
 
@@ -153,7 +154,9 @@ EmulateInstructionMIPS64::EmulateInstructionMIPS64(
   m_insn_info.reset(target->createMCInstrInfo());
   assert(m_insn_info.get());
 
-  m_asm_info.reset(target->createMCAsmInfo(*m_reg_info, triple.getTriple()));
+  llvm::MCTargetOptions MCOptions;
+  m_asm_info.reset(
+      target->createMCAsmInfo(*m_reg_info, triple.getTriple(), MCOptions));
   m_subtype_info.reset(
       target->createMCSubtargetInfo(triple.getTriple(), cpu, features));
   assert(m_asm_info.get() && m_subtype_info.get());
@@ -962,8 +965,8 @@ bool EmulateInstructionMIPS64::EvaluateInstruction(uint32_t evaluate_options) {
   if (m_opcode.GetData(data)) {
     llvm::MCDisassembler::DecodeStatus decode_status;
     llvm::ArrayRef<uint8_t> raw_insn(data.GetDataStart(), data.GetByteSize());
-    decode_status = m_disasm->getInstruction(
-        mc_insn, insn_size, raw_insn, m_addr, llvm::nulls(), llvm::nulls());
+    decode_status = m_disasm->getInstruction(mc_insn, insn_size, raw_insn,
+                                             m_addr, llvm::nulls());
     if (decode_status != llvm::MCDisassembler::Success)
       return false;
   }
@@ -1360,7 +1363,7 @@ bool EmulateInstructionMIPS64::Emulate_BXX_3ops(llvm::MCInst &insn) {
   if (!success)
     return false;
 
-  if (!strcasecmp(op_name, "BEQ") || !strcasecmp(op_name, "BEQL") 
+  if (!strcasecmp(op_name, "BEQ") || !strcasecmp(op_name, "BEQL")
        || !strcasecmp(op_name, "BEQ64") ) {
     if (rs_val == rt_val)
       target = pc + offset;
@@ -1602,7 +1605,7 @@ bool EmulateInstructionMIPS64::Emulate_BXX_2ops(llvm::MCInst &insn) {
       target = pc + offset;
     else
       target = pc + 8;
-  } else if (!strcasecmp(op_name, "BLEZL") || !strcasecmp(op_name, "BLEZ") 
+  } else if (!strcasecmp(op_name, "BLEZL") || !strcasecmp(op_name, "BLEZ")
               || !strcasecmp(op_name, "BLEZ64")) {
     if (rs_val <= 0)
       target = pc + offset;
diff --git a/lldb/source/Plugins/InstrumentationRuntime/MainThreadChecker/MainThreadCheckerRuntime.cpp b/lldb/source/Plugins/InstrumentationRuntime/MainThreadChecker/MainThreadCheckerRuntime.cpp
index dfe61316b042..b73b6c095368 100644
--- a/lldb/source/Plugins/InstrumentationRuntime/MainThreadChecker/MainThreadCheckerRuntime.cpp
+++ b/lldb/source/Plugins/InstrumentationRuntime/MainThreadChecker/MainThreadCheckerRuntime.cpp
@@ -153,7 +153,7 @@ bool MainThreadCheckerRuntime::NotifyBreakpointHit(
     user_id_t break_loc_id) {
   assert(baton && "null baton");
   if (!baton)
-    return false; //< false => resume execution.
+    return false; ///< false => resume execution.
 
   MainThreadCheckerRuntime *const instance =
       static_cast<MainThreadCheckerRuntime *>(baton);
@@ -241,30 +241,30 @@ MainThreadCheckerRuntime::GetBacktracesFromExtendedStopInfo(
     StructuredData::ObjectSP info) {
   ThreadCollectionSP threads;
   threads = std::make_shared<ThreadCollection>();
-  
+
   ProcessSP process_sp = GetProcessSP();
-  
+
   if (info->GetObjectForDotSeparatedPath("instrumentation_class")
       ->GetStringValue() != "MainThreadChecker")
     return threads;
-  
+
   std::vector<lldb::addr_t> PCs;
   auto trace = info->GetObjectForDotSeparatedPath("trace")->GetAsArray();
   trace->ForEach([&PCs](StructuredData::Object *PC) -> bool {
     PCs.push_back(PC->GetAsInteger()->GetValue());
     return true;
   });
-  
+
   if (PCs.empty())
     return threads;
-  
+
   StructuredData::ObjectSP thread_id_obj =
       info->GetObjectForDotSeparatedPath("tid");
   tid_t tid = thread_id_obj ? thread_id_obj->GetIntegerValue() : 0;
 
   HistoryThread *history_thread = new HistoryThread(*process_sp, tid, PCs);
   ThreadSP new_thread_sp(history_thread);
-  
+
   // Save this in the Process' ExtendedThreadList so a strong pointer retains
   // the object
   process_sp->GetExtendedThreadList().AddThread(new_thread_sp);
diff --git a/lldb/source/Plugins/InstrumentationRuntime/UBSan/UBSanRuntime.cpp b/lldb/source/Plugins/InstrumentationRuntime/UBSan/UBSanRuntime.cpp
index 50f1d48d03e0..137ecab224bc 100644
--- a/lldb/source/Plugins/InstrumentationRuntime/UBSan/UBSanRuntime.cpp
+++ b/lldb/source/Plugins/InstrumentationRuntime/UBSan/UBSanRuntime.cpp
@@ -207,7 +207,7 @@ bool UndefinedBehaviorSanitizerRuntime::NotifyBreakpointHit(
     user_id_t break_loc_id) {
   assert(baton && "null baton");
   if (!baton)
-    return false; //< false => resume execution.
+    return false; ///< false => resume execution.
 
   UndefinedBehaviorSanitizerRuntime *const instance =
       static_cast<UndefinedBehaviorSanitizerRuntime *>(baton);
diff --git a/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp b/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp
index 489fa7d0ad91..4385a60f5862 100644
--- a/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp
+++ b/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp
@@ -19,6 +19,7 @@
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Demangle/ItaniumDemangle.h"
 
+#include "lldb/Core/Mangled.h"
 #include "lldb/Core/PluginManager.h"
 #include "lldb/Core/UniqueCStringMap.h"
 #include "lldb/DataFormatters/CXXFunctionPointer.h"
@@ -238,18 +239,16 @@ std::string CPlusPlusLanguage::MethodName::GetScopeQualifiedName() {
   return res;
 }
 
-bool CPlusPlusLanguage::IsCPPMangledName(const char *name) {
+bool CPlusPlusLanguage::IsCPPMangledName(llvm::StringRef name) {
   // FIXME!! we should really run through all the known C++ Language plugins
   // and ask each one if this is a C++ mangled name
 
-  if (name == nullptr)
-    return false;
+  Mangled::ManglingScheme scheme = Mangled::GetManglingScheme(name);
 
-  // MSVC style mangling
-  if (name[0] == '?')
-    return true;
+  if (scheme == Mangled::eManglingSchemeNone)
+    return false;
 
-  return (name[0] != '\0' && name[0] == '_' && name[1] == 'Z');
+  return true;
 }
 
 bool CPlusPlusLanguage::ExtractContextAndIdentifier(
@@ -285,46 +284,34 @@ public:
   }
 };
 
-/// Given a mangled function `Mangled`, replace all the primitive function type
-/// arguments of `Search` with type `Replace`.
-class TypeSubstitutor
-    : public llvm::itanium_demangle::AbstractManglingParser<TypeSubstitutor,
+template <typename Derived>
+class ManglingSubstitutor
+    : public llvm::itanium_demangle::AbstractManglingParser<Derived,
                                                             NodeAllocator> {
-  /// Input character until which we have constructed the respective output
-  /// already
-  const char *Written;
+  using Base =
+      llvm::itanium_demangle::AbstractManglingParser<Derived, NodeAllocator>;
 
-  llvm::StringRef Search;
-  llvm::StringRef Replace;
-  llvm::SmallString<128> Result;
+public:
+  ManglingSubstitutor() : Base(nullptr, nullptr) {}
 
-  /// Whether we have performed any substitutions.
-  bool Substituted;
+  template<typename... Ts>
+  ConstString substitute(llvm::StringRef Mangled, Ts &&... Vals) {
+    this->getDerived().reset(Mangled, std::forward<Ts>(Vals)...);
+    return substituteImpl(Mangled);
+  }
 
-  void reset(llvm::StringRef Mangled, llvm::StringRef Search,
-             llvm::StringRef Replace) {
-    AbstractManglingParser::reset(Mangled.begin(), Mangled.end());
+
+protected:
+  void reset(llvm::StringRef Mangled) {
+    Base::reset(Mangled.begin(), Mangled.end());
     Written = Mangled.begin();
-    this->Search = Search;
-    this->Replace = Replace;
     Result.clear();
     Substituted = false;
   }
 
-  void appendUnchangedInput() {
-    Result += llvm::StringRef(Written, First - Written);
-    Written = First;
-  }
-
-public:
-  TypeSubstitutor() : AbstractManglingParser(nullptr, nullptr) {}
-
-  ConstString substitute(llvm::StringRef Mangled, llvm::StringRef From,
-                         llvm::StringRef To) {
+  ConstString substituteImpl(llvm::StringRef Mangled) {
     Log *log = GetLogIfAllCategoriesSet(LIBLLDB_LOG_LANGUAGE);
-
-    reset(Mangled, From, To);
-    if (parse() == nullptr) {
+    if (this->parse() == nullptr) {
       LLDB_LOG(log, "Failed to substitute mangling in {0}", Mangled);
       return ConstString();
     }
@@ -337,20 +324,69 @@ public:
     return ConstString(Result);
   }
 
+  void trySubstitute(llvm::StringRef From, llvm::StringRef To) {
+    if (!llvm::StringRef(currentParserPos(), this->numLeft()).startswith(From))
+      return;
+
+    // We found a match. Append unmodified input up to this point.
+    appendUnchangedInput();
+
+    // And then perform the replacement.
+    Result += To;
+    Written += From.size();
+    Substituted = true;
+  }
+
+private:
+  /// Input character until which we have constructed the respective output
+  /// already.
+  const char *Written;
+
+  llvm::SmallString<128> Result;
+
+  /// Whether we have performed any substitutions.
+  bool Substituted;
+
+  const char *currentParserPos() const { return this->First; }
+
+  void appendUnchangedInput() {
+    Result +=
+        llvm::StringRef(Written, std::distance(Written, currentParserPos()));
+    Written = currentParserPos();
+  }
+
+};
+
+/// Given a mangled function `Mangled`, replace all the primitive function type
+/// arguments of `Search` with type `Replace`.
+class TypeSubstitutor : public ManglingSubstitutor<TypeSubstitutor> {
+  llvm::StringRef Search;
+  llvm::StringRef Replace;
+
+public:
+  void reset(llvm::StringRef Mangled, llvm::StringRef Search,
+             llvm::StringRef Replace) {
+    ManglingSubstitutor::reset(Mangled);
+    this->Search = Search;
+    this->Replace = Replace;
+  }
+
   llvm::itanium_demangle::Node *parseType() {
-    if (llvm::StringRef(First, numLeft()).startswith(Search)) {
-      // We found a match. Append unmodified input up to this point.
-      appendUnchangedInput();
-
-      // And then perform the replacement.
-      Result += Replace;
-      Written += Search.size();
-      Substituted = true;
-    }
-    return AbstractManglingParser::parseType();
+    trySubstitute(Search, Replace);
+    return ManglingSubstitutor::parseType();
   }
 };
-}
+
+class CtorDtorSubstitutor : public ManglingSubstitutor<CtorDtorSubstitutor> {
+public:
+  llvm::itanium_demangle::Node *
+  parseCtorDtorName(llvm::itanium_demangle::Node *&SoFar, NameState *State) {
+    trySubstitute("C1", "C2");
+    trySubstitute("D1", "D2");
+    return ManglingSubstitutor::parseCtorDtorName(SoFar, State);
+  }
+};
+} // namespace
 
 uint32_t CPlusPlusLanguage::FindAlternateFunctionManglings(
     const ConstString mangled_name, std::set<ConstString> &alternates) {
@@ -398,6 +434,10 @@ uint32_t CPlusPlusLanguage::FindAlternateFunctionManglings(
           TS.substitute(mangled_name.GetStringRef(), "y", "m"))
     alternates.insert(ulong_fixup);
 
+  if (ConstString ctor_fixup =
+          CtorDtorSubstitutor().substitute(mangled_name.GetStringRef()))
+    alternates.insert(ctor_fixup);
+
   return alternates.size() - start_size;
 }
 
@@ -426,6 +466,13 @@ static void LoadLibCxxFormatters(lldb::TypeCategoryImplSP cpp_category_sp) {
                             "std::__[[:alnum:]]+::char_traits<char>, "
                             "std::__[[:alnum:]]+::allocator<char> >$"),
                 stl_summary_flags, true);
+  AddCXXSummary(cpp_category_sp,
+                lldb_private::formatters::LibcxxStringSummaryProviderASCII,
+                "std::string summary provider",
+                ConstString("^std::__[[:alnum:]]+::basic_string<unsigned char, "
+                            "std::__[[:alnum:]]+::char_traits<unsigned char>, "
+                            "std::__[[:alnum:]]+::allocator<unsigned char> >$"),
+                stl_summary_flags, true);
 
   AddCXXSummary(cpp_category_sp,
                 lldb_private::formatters::LibcxxStringSummaryProviderUTF16,
@@ -568,6 +615,11 @@ static void LoadLibCxxFormatters(lldb::TypeCategoryImplSP cpp_category_sp) {
       "weak_ptr synthetic children",
       ConstString("^(std::__[[:alnum:]]+::)weak_ptr<.+>(( )?&)?$"),
       stl_synth_flags, true);
+  AddCXXSummary(cpp_category_sp,
+                lldb_private::formatters::LibcxxFunctionSummaryProvider,
+                "libc++ std::function summary provider",
+                ConstString("^std::__[[:alnum:]]+::function<.+>$"),
+                stl_summary_flags, true);
 
   stl_summary_flags.SetDontShowChildren(false);
   stl_summary_flags.SetSkipPointers(false);
@@ -719,6 +771,10 @@ static void LoadLibStdcppFormatters(lldb::TypeCategoryImplSP cpp_category_sp) {
       ConstString("std::__cxx11::basic_string<char, std::char_traits<char>, "
                   "std::allocator<char> >"),
       cxx11_string_summary_sp);
+  cpp_category_sp->GetTypeSummariesContainer()->Add(
+      ConstString("std::__cxx11::basic_string<unsigned char, std::char_traits<unsigned char>, "
+                  "std::allocator<unsigned char> >"),
+      cxx11_string_summary_sp);
 
   // making sure we force-pick the summary for printing wstring (_M_p is a
   // wchar_t*)
diff --git a/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.h b/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.h
index d30e56080732..4ed45bc904ce 100644
--- a/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.h
+++ b/lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.h
@@ -101,7 +101,7 @@ public:
 
   static lldb_private::ConstString GetPluginNameStatic();
 
-  static bool IsCPPMangledName(const char *name);
+  static bool IsCPPMangledName(llvm::StringRef name);
 
   // Extract C++ context and identifier from a string using heuristic matching
   // (as opposed to
diff --git a/lldb/source/Plugins/Language/CPlusPlus/LibCxx.cpp b/lldb/source/Plugins/Language/CPlusPlus/LibCxx.cpp
index abe89035c532..ecadaef7a87e 100644
--- a/lldb/source/Plugins/Language/CPlusPlus/LibCxx.cpp
+++ b/lldb/source/Plugins/Language/CPlusPlus/LibCxx.cpp
@@ -572,10 +572,13 @@ bool lldb_private::formatters::LibcxxWStringSummaryProvider(
   location_sp->GetPointeeData(extractor, 0, size);
 
   // std::wstring::size() is measured in 'characters', not bytes
-  auto wchar_t_size = valobj.GetTargetSP()
-                          ->GetScratchClangASTContext()
-                          ->GetBasicType(lldb::eBasicTypeWChar)
-                          .GetByteSize(nullptr);
+  ClangASTContext *ast_context =
+      ClangASTContext::GetScratch(*valobj.GetTargetSP());
+  if (!ast_context)
+    return false;
+
+  auto wchar_t_size =
+      ast_context->GetBasicType(lldb::eBasicTypeWChar).GetByteSize(nullptr);
   if (!wchar_t_size)
     return false;
 
diff --git a/lldb/source/Plugins/Language/CPlusPlus/LibCxxMap.cpp b/lldb/source/Plugins/Language/CPlusPlus/LibCxxMap.cpp
index 619c718a1c1b..f6d8d4d9a7eb 100644
--- a/lldb/source/Plugins/Language/CPlusPlus/LibCxxMap.cpp
+++ b/lldb/source/Plugins/Language/CPlusPlus/LibCxxMap.cpp
@@ -94,6 +94,8 @@ public:
   MapIterator(ValueObject *entry, size_t depth = 0)
       : m_entry(entry), m_max_depth(depth), m_error(false) {}
 
+  MapIterator &operator=(const MapIterator &) = default;
+
   ValueObjectSP value() { return m_entry.GetEntry(); }
 
   ValueObjectSP advance(size_t count) {
diff --git a/lldb/source/Plugins/Language/ClangCommon/ClangHighlighter.cpp b/lldb/source/Plugins/Language/ClangCommon/ClangHighlighter.cpp
index a9a1b44731f2..3e77b1646739 100644
--- a/lldb/source/Plugins/Language/ClangCommon/ClangHighlighter.cpp
+++ b/lldb/source/Plugins/Language/ClangCommon/ClangHighlighter.cpp
@@ -139,6 +139,22 @@ void ClangHighlighter::Highlight(const HighlightStyle &options,
   FileManager file_mgr(file_opts,
                        FileSystem::Instance().GetVirtualFileSystem());
 
+  // The line might end in a backslash which would cause Clang to drop the
+  // backslash and the terminating new line. This makes sense when parsing C++,
+  // but when highlighting we care about preserving the backslash/newline. To
+  // not lose this information we remove the new line here so that Clang knows
+  // this is just a single line we are highlighting. We add back the newline
+  // after tokenizing.
+  llvm::StringRef line_ending = "";
+  // There are a few legal line endings Clang recognizes and we need to
+  // temporarily remove from the string.
+  if (line.consume_back("\r\n"))
+    line_ending = "\r\n";
+  else if (line.consume_back("\n"))
+    line_ending = "\n";
+  else if (line.consume_back("\r"))
+    line_ending = "\r";
+
   unsigned line_number = previous_lines.count('\n') + 1U;
 
   // Let's build the actual source code Clang needs and setup some utility
@@ -227,6 +243,9 @@ void ClangHighlighter::Highlight(const HighlightStyle &options,
     color.Apply(result, to_print);
   }
 
+  // Add the line ending we trimmed before tokenizing.
+  result << line_ending;
+
   // If we went over the whole file but couldn't find our own file, then
   // somehow our setup was wrong. When we're in release mode we just give the
   // user the normal line and pretend we don't know how to highlight it. In
diff --git a/lldb/source/Plugins/Language/ObjC/Cocoa.cpp b/lldb/source/Plugins/Language/ObjC/Cocoa.cpp
index ddf3953bb512..8a81abbaedbe 100644
--- a/lldb/source/Plugins/Language/ObjC/Cocoa.cpp
+++ b/lldb/source/Plugins/Language/ObjC/Cocoa.cpp
@@ -694,32 +694,44 @@ bool lldb_private::formatters::NSURLSummaryProvider(
   CompilerType type(valobj.GetCompilerType());
   ValueObjectSP text(valobj.GetSyntheticChildAtOffset(offset_text, type, true));
   ValueObjectSP base(valobj.GetSyntheticChildAtOffset(offset_base, type, true));
-  if (!text)
-    return false;
-  if (text->GetValueAsUnsigned(0) == 0)
+  if (!text || text->GetValueAsUnsigned(0) == 0)
     return false;
+
+  StreamString base_summary;
+  if (base && base->GetValueAsUnsigned(0)) {
+    if (!NSURLSummaryProvider(*base, base_summary, options))
+      base_summary.Clear();
+  }
+  if (base_summary.Empty())
+    return NSStringSummaryProvider(*text, stream, options);
+
   StreamString summary;
-  if (!NSStringSummaryProvider(*text, summary, options))
+  if (!NSStringSummaryProvider(*text, summary, options) || summary.Empty())
     return false;
-  if (base && base->GetValueAsUnsigned(0)) {
-    std::string summary_str = summary.GetString();
-
-    if (!summary_str.empty())
-      summary_str.pop_back();
-    summary_str += " -- ";
-    StreamString base_summary;
-    if (NSURLSummaryProvider(*base, base_summary, options) &&
-        !base_summary.Empty()) {
-      llvm::StringRef base_str = base_summary.GetString();
-      if (base_str.size() > 2)
-        base_str = base_str.drop_front(2);
-      summary_str += base_str;
+
+  const char quote_char = '"';
+  std::string prefix, suffix;
+  if (Language *language = Language::FindPlugin(options.GetLanguage())) {
+    if (!language->GetFormatterPrefixSuffix(*text, ConstString("NSString"),
+                                            prefix, suffix)) {
+      prefix.clear();
+      suffix.clear();
     }
-    summary.Clear();
-    summary.PutCString(summary_str);
   }
-  if (!summary.Empty()) {
-    stream.PutCString(summary.GetString());
+  // @"A" -> @"A
+  llvm::StringRef summary_str = summary.GetString();
+  bool back_consumed = summary_str.consume_back(quote_char + suffix);
+  assert(back_consumed);
+  UNUSED_IF_ASSERT_DISABLED(back_consumed);
+  // @"B" -> B"
+  llvm::StringRef base_summary_str = base_summary.GetString();
+  bool front_consumed = base_summary_str.consume_front(prefix + quote_char);
+  assert(front_consumed);
+  UNUSED_IF_ASSERT_DISABLED(front_consumed);
+  // @"A -- B"
+  if (!summary_str.empty() && !base_summary_str.empty()) {
+    stream.Printf("%s -- %s", summary_str.str().c_str(),
+                  base_summary_str.str().c_str());
     return true;
   }
 
diff --git a/lldb/source/Plugins/Language/ObjC/NSArray.cpp b/lldb/source/Plugins/Language/ObjC/NSArray.cpp
index 7219c016dfd1..73335aff2fd7 100644
--- a/lldb/source/Plugins/Language/ObjC/NSArray.cpp
+++ b/lldb/source/Plugins/Language/ObjC/NSArray.cpp
@@ -96,31 +96,6 @@ private:
   D64 *m_data_64;
 };
   
-namespace Foundation109 {
-  struct DataDescriptor_32 {
-    uint32_t _used;
-    uint32_t _priv1 : 2;
-    uint32_t _size : 30;
-    uint32_t _priv2 : 2;
-    uint32_t _offset : 30;
-    uint32_t _priv3;
-    uint32_t _data;
-  };
-  
-  struct DataDescriptor_64 {
-    uint64_t _used;
-    uint64_t _priv1 : 2;
-    uint64_t _size : 62;
-    uint64_t _priv2 : 2;
-    uint64_t _offset : 62;
-    uint32_t _priv3;
-    uint64_t _data;
-  };
-  
-  using NSArrayMSyntheticFrontEnd =
-      GenericNSArrayMSyntheticFrontEnd<DataDescriptor_32, DataDescriptor_64>;
-}
-  
 namespace Foundation1010 {
   struct DataDescriptor_32 {
     uint32_t _used;
@@ -461,13 +436,12 @@ lldb_private::formatters::NSArrayMSyntheticFrontEndBase::NSArrayMSyntheticFrontE
     : SyntheticChildrenFrontEnd(*valobj_sp), m_exe_ctx_ref(), m_ptr_size(8),
       m_id_type() {
   if (valobj_sp) {
-    auto *clang_ast_context = valobj_sp->GetExecutionContextRef()
-                                  .GetTargetSP()
-                                  ->GetScratchClangASTContext();
+    auto *clang_ast_context = ClangASTContext::GetScratch(
+        *valobj_sp->GetExecutionContextRef().GetTargetSP());
     if (clang_ast_context)
       m_id_type = CompilerType(
           clang_ast_context,
-          clang_ast_context->getASTContext()->ObjCBuiltinIdTy.getAsOpaquePtr());
+          clang_ast_context->getASTContext().ObjCBuiltinIdTy.getAsOpaquePtr());
     if (valobj_sp->GetProcessSP())
       m_ptr_size = valobj_sp->GetProcessSP()->GetAddressByteSize();
   }
@@ -610,13 +584,11 @@ lldb_private::formatters::GenericNSArrayISyntheticFrontEnd<D32, D64, Inline>::
   if (valobj_sp) {
     CompilerType type = valobj_sp->GetCompilerType();
     if (type) {
-      auto *clang_ast_context = valobj_sp->GetExecutionContextRef()
-                                    .GetTargetSP()
-                                    ->GetScratchClangASTContext();
+      auto *clang_ast_context = ClangASTContext::GetScratch(
+          *valobj_sp->GetExecutionContextRef().GetTargetSP());
       if (clang_ast_context)
-        m_id_type = CompilerType(clang_ast_context,
-                                 clang_ast_context->getASTContext()
-                                     ->ObjCBuiltinIdTy.getAsOpaquePtr());
+        m_id_type = clang_ast_context->GetType(
+            clang_ast_context->getASTContext().ObjCBuiltinIdTy);
     }
   }
 }
@@ -780,11 +752,15 @@ lldb_private::formatters::NSArray1SyntheticFrontEnd::GetChildAtIndex(
   static const ConstString g_zero("[0]");
 
   if (idx == 0) {
-    CompilerType id_type(
-        m_backend.GetTargetSP()->GetScratchClangASTContext()->GetBasicType(
-            lldb::eBasicTypeObjCID));
-    return m_backend.GetSyntheticChildAtOffset(
-        m_backend.GetProcessSP()->GetAddressByteSize(), id_type, true, g_zero);
+    auto *clang_ast_context =
+        ClangASTContext::GetScratch(*m_backend.GetTargetSP());
+    if (clang_ast_context) {
+      CompilerType id_type(
+          clang_ast_context->GetBasicType(lldb::eBasicTypeObjCID));
+      return m_backend.GetSyntheticChildAtOffset(
+          m_backend.GetProcessSP()->GetAddressByteSize(), id_type, true,
+          g_zero);
+    }
   }
   return lldb::ValueObjectSP();
 }
@@ -857,8 +833,6 @@ lldb_private::formatters::NSArraySyntheticFrontEndCreator(
       return (new Foundation1428::NSArrayMSyntheticFrontEnd(valobj_sp));
     if (runtime->GetFoundationVersion() >= 1100)
       return (new Foundation1010::NSArrayMSyntheticFrontEnd(valobj_sp));
-    else
-      return (new Foundation109::NSArrayMSyntheticFrontEnd(valobj_sp));
   } else if (class_name == g_NSCallStackArray) {
     return (new CallStackArray::NSCallStackArraySyntheticFrontEnd(valobj_sp));
   } else {
diff --git a/lldb/source/Plugins/Language/ObjC/NSDictionary.cpp b/lldb/source/Plugins/Language/ObjC/NSDictionary.cpp
index 10f66c4a37f8..ae00674c49f3 100644
--- a/lldb/source/Plugins/Language/ObjC/NSDictionary.cpp
+++ b/lldb/source/Plugins/Language/ObjC/NSDictionary.cpp
@@ -65,7 +65,7 @@ NSDictionary_Additionals::GetAdditionalSynthetics() {
 static CompilerType GetLLDBNSPairType(TargetSP target_sp) {
   CompilerType compiler_type;
 
-  ClangASTContext *target_ast_context = target_sp->GetScratchClangASTContext();
+  ClangASTContext *target_ast_context = ClangASTContext::GetScratch(*target_sp);
 
   if (target_ast_context) {
     ConstString g___lldb_autogen_nspair("__lldb_autogen_nspair");
diff --git a/lldb/source/Plugins/Language/ObjC/NSError.cpp b/lldb/source/Plugins/Language/ObjC/NSError.cpp
index 97df3be72c84..94a97c8ad039 100644
--- a/lldb/source/Plugins/Language/ObjC/NSError.cpp
+++ b/lldb/source/Plugins/Language/ObjC/NSError.cpp
@@ -86,10 +86,10 @@ bool lldb_private::formatters::NSError_SummaryProvider(
 
   ValueObjectSP domain_str_sp = ValueObject::CreateValueObjectFromData(
       "domain_str", isw.GetAsData(process_sp->GetByteOrder()),
-      valobj.GetExecutionContextRef(), process_sp->GetTarget()
-                                           .GetScratchClangASTContext()
-                                           ->GetBasicType(lldb::eBasicTypeVoid)
-                                           .GetPointerType());
+      valobj.GetExecutionContextRef(),
+      ClangASTContext::GetScratch(process_sp->GetTarget())
+          ->GetBasicType(lldb::eBasicTypeVoid)
+          .GetPointerType());
 
   if (!domain_str_sp)
     return false;
@@ -156,8 +156,8 @@ public:
     m_child_sp = CreateValueObjectFromData(
         "_userInfo", isw.GetAsData(process_sp->GetByteOrder()),
         m_backend.GetExecutionContextRef(),
-        process_sp->GetTarget().GetScratchClangASTContext()->GetBasicType(
-            lldb::eBasicTypeObjCID));
+        ClangASTContext::GetScratch(process_sp->GetTarget())
+            ->GetBasicType(lldb::eBasicTypeObjCID));
     return false;
   }
 
diff --git a/lldb/source/Plugins/Language/ObjC/NSException.cpp b/lldb/source/Plugins/Language/ObjC/NSException.cpp
index 931794a12ab1..9150787361c5 100644
--- a/lldb/source/Plugins/Language/ObjC/NSException.cpp
+++ b/lldb/source/Plugins/Language/ObjC/NSException.cpp
@@ -69,10 +69,12 @@ static bool ExtractFields(ValueObject &valobj, ValueObjectSP *name_sp,
   InferiorSizedWord userinfo_isw(userinfo, *process_sp);
   InferiorSizedWord reserved_isw(reserved, *process_sp);
 
-  CompilerType voidstar = process_sp->GetTarget()
-                              .GetScratchClangASTContext()
-                              ->GetBasicType(lldb::eBasicTypeVoid)
-                              .GetPointerType();
+  auto *clang_ast_context = ClangASTContext::GetScratch(process_sp->GetTarget());
+  if (!clang_ast_context)
+    return false;
+
+  CompilerType voidstar =
+      clang_ast_context->GetBasicType(lldb::eBasicTypeVoid).GetPointerType();
 
   if (name_sp)
     *name_sp = ValueObject::CreateValueObjectFromData(
@@ -96,21 +98,19 @@ static bool ExtractFields(ValueObject &valobj, ValueObjectSP *name_sp,
 
 bool lldb_private::formatters::NSException_SummaryProvider(
     ValueObject &valobj, Stream &stream, const TypeSummaryOptions &options) {
-  lldb::ValueObjectSP name_sp;
   lldb::ValueObjectSP reason_sp;
-  if (!ExtractFields(valobj, &name_sp, &reason_sp, nullptr, nullptr))
+  if (!ExtractFields(valobj, nullptr, &reason_sp, nullptr, nullptr))
     return false;
 
-  if (!name_sp || !reason_sp)
+  if (!reason_sp) {
+    stream.Printf("No reason");
     return false;
+  }
 
-  StreamString name_str_summary;
   StreamString reason_str_summary;
-  if (NSStringSummaryProvider(*name_sp, name_str_summary, options) &&
-      NSStringSummaryProvider(*reason_sp, reason_str_summary, options) &&
-      !name_str_summary.Empty() && !reason_str_summary.Empty()) {
-    stream.Printf("name: %s - reason: %s", name_str_summary.GetData(),
-                  reason_str_summary.GetData());
+  if (NSStringSummaryProvider(*reason_sp, reason_str_summary, options) &&
+      !reason_str_summary.Empty()) {
+    stream.Printf("%s", reason_str_summary.GetData());
     return true;
   } else
     return false;
diff --git a/lldb/source/Plugins/Language/ObjC/NSIndexPath.cpp b/lldb/source/Plugins/Language/ObjC/NSIndexPath.cpp
index 9ee6021ae56b..587dd13870a0 100644
--- a/lldb/source/Plugins/Language/ObjC/NSIndexPath.cpp
+++ b/lldb/source/Plugins/Language/ObjC/NSIndexPath.cpp
@@ -53,9 +53,8 @@ public:
     if (!type_system)
       return false;
 
-    ClangASTContext *ast = m_backend.GetExecutionContextRef()
-                               .GetTargetSP()
-                               ->GetScratchClangASTContext();
+    ClangASTContext *ast = ClangASTContext::GetScratch(
+        *m_backend.GetExecutionContextRef().GetTargetSP());
     if (!ast)
       return false;
 
diff --git a/lldb/source/Plugins/Language/ObjC/NSString.cpp b/lldb/source/Plugins/Language/ObjC/NSString.cpp
index 55e129b098dc..ce54d657374b 100644
--- a/lldb/source/Plugins/Language/ObjC/NSString.cpp
+++ b/lldb/source/Plugins/Language/ObjC/NSString.cpp
@@ -35,7 +35,7 @@ NSString_Additionals::GetAdditionalSummaries() {
 static CompilerType GetNSPathStore2Type(Target &target) {
   static ConstString g_type_name("__lldb_autogen_nspathstore2");
 
-  ClangASTContext *ast_ctx = target.GetScratchClangASTContext();
+  ClangASTContext *ast_ctx = ClangASTContext::GetScratch(target);
 
   if (!ast_ctx)
     return CompilerType();
diff --git a/lldb/source/Plugins/Language/ObjC/ObjCLanguage.cpp b/lldb/source/Plugins/Language/ObjC/ObjCLanguage.cpp
index c5bfb5747c13..3be548ad4144 100644
--- a/lldb/source/Plugins/Language/ObjC/ObjCLanguage.cpp
+++ b/lldb/source/Plugins/Language/ObjC/ObjCLanguage.cpp
@@ -15,6 +15,7 @@
 #include "lldb/DataFormatters/DataVisualization.h"
 #include "lldb/DataFormatters/FormattersHelpers.h"
 #include "lldb/Symbol/ClangASTContext.h"
+#include "lldb/Symbol/ClangUtil.h"
 #include "lldb/Symbol/CompilerType.h"
 #include "lldb/Target/Target.h"
 #include "lldb/Utility/ConstString.h"
@@ -887,7 +888,7 @@ ObjCLanguage::GetPossibleFormattersMatches(ValueObject &valobj,
   bool canBeObjCDynamic =
       compiler_type.IsPossibleDynamicType(nullptr, check_cpp, check_objc);
 
-  if (canBeObjCDynamic) {
+  if (canBeObjCDynamic && ClangUtil::IsClangType(compiler_type)) {
     do {
       lldb::ProcessSP process_sp = valobj.GetProcessSP();
       if (!process_sp)
diff --git a/lldb/source/Plugins/LanguageRuntime/CPlusPlus/CPPLanguageRuntime.cpp b/lldb/source/Plugins/LanguageRuntime/CPlusPlus/CPPLanguageRuntime.cpp
index f38014505a8b..d556aae1c458 100644
--- a/lldb/source/Plugins/LanguageRuntime/CPlusPlus/CPPLanguageRuntime.cpp
+++ b/lldb/source/Plugins/LanguageRuntime/CPlusPlus/CPPLanguageRuntime.cpp
@@ -21,6 +21,7 @@
 #include "lldb/Core/PluginManager.h"
 #include "lldb/Core/UniqueCStringMap.h"
 #include "lldb/Symbol/ClangASTContext.h"
+#include "lldb/Symbol/CompileUnit.h"
 #include "lldb/Target/ABI.h"
 #include "lldb/Target/ExecutionContext.h"
 #include "lldb/Target/RegisterContext.h"
@@ -28,6 +29,7 @@
 #include "lldb/Target/StackFrame.h"
 #include "lldb/Target/ThreadPlanRunToAddress.h"
 #include "lldb/Target/ThreadPlanStepInRange.h"
+#include "lldb/Utility/Timer.h"
 
 using namespace lldb;
 using namespace lldb_private;
@@ -58,9 +60,53 @@ bool CPPLanguageRuntime::GetObjectDescription(
   return false;
 }
 
+bool contains_lambda_identifier(llvm::StringRef &str_ref) {
+  return str_ref.contains("$_") || str_ref.contains("'lambda'");
+}
+
+CPPLanguageRuntime::LibCppStdFunctionCallableInfo
+line_entry_helper(Target &target, const SymbolContext &sc, Symbol *symbol,
+                  llvm::StringRef first_template_param_sref,
+                  bool has___invoke) {
+
+  CPPLanguageRuntime::LibCppStdFunctionCallableInfo optional_info;
+
+  AddressRange range;
+  sc.GetAddressRange(eSymbolContextEverything, 0, false, range);
+
+  Address address = range.GetBaseAddress();
+
+  Address addr;
+  if (target.ResolveLoadAddress(address.GetCallableLoadAddress(&target),
+                                addr)) {
+    LineEntry line_entry;
+    addr.CalculateSymbolContextLineEntry(line_entry);
+
+    if (contains_lambda_identifier(first_template_param_sref) || has___invoke) {
+      // Case 1 and 2
+      optional_info.callable_case = lldb_private::CPPLanguageRuntime::
+          LibCppStdFunctionCallableCase::Lambda;
+    } else {
+      // Case 3
+      optional_info.callable_case = lldb_private::CPPLanguageRuntime::
+          LibCppStdFunctionCallableCase::CallableObject;
+    }
+
+    optional_info.callable_symbol = *symbol;
+    optional_info.callable_line_entry = line_entry;
+    optional_info.callable_address = addr;
+  }
+
+  return optional_info;
+}
+
 CPPLanguageRuntime::LibCppStdFunctionCallableInfo
 CPPLanguageRuntime::FindLibCppStdFunctionCallableInfo(
     lldb::ValueObjectSP &valobj_sp) {
+  static Timer::Category func_cat(LLVM_PRETTY_FUNCTION);
+  Timer scoped_timer(func_cat,
+                     "CPPLanguageRuntime::FindLibCppStdFunctionCallableInfo");
+
   LibCppStdFunctionCallableInfo optional_info;
 
   if (!valobj_sp)
@@ -93,7 +139,7 @@ CPPLanguageRuntime::FindLibCppStdFunctionCallableInfo(
   //    this entry and lookup operator()() and obtain the line table entry.
   // 3) a callable object via operator()(). We will obtain the name of the
   //    object from the first template parameter from __func's vtable. We will
-  //    look up the objectc operator()() and obtain the line table entry.
+  //    look up the objects operator()() and obtain the line table entry.
   // 4) a member function. A pointer to the function will stored after the
   //    we will obtain the name from this pointer.
   // 5) a free function. A pointer to the function will stored after the vtable
@@ -113,6 +159,9 @@ CPPLanguageRuntime::FindLibCppStdFunctionCallableInfo(
 
   optional_info.member__f_pointer_value = member__f_pointer_value;
 
+  if (!member__f_pointer_value)
+    return optional_info;
+
   ExecutionContext exe_ctx(valobj_sp->GetExecutionContextRef());
   Process *process = exe_ctx.GetProcessPtr();
 
@@ -130,8 +179,14 @@ CPPLanguageRuntime::FindLibCppStdFunctionCallableInfo(
   if (status.Fail())
     return optional_info;
 
+  lldb::addr_t vtable_address_first_entry =
+      process->ReadPointerFromMemory(vtable_address + address_size, status);
+
+  if (status.Fail())
+    return optional_info;
+
   lldb::addr_t address_after_vtable = member__f_pointer_value + address_size;
-  // As commened above we may not have a function pointer but if we do we will
+  // As commented above we may not have a function pointer but if we do we will
   // need it.
   lldb::addr_t possible_function_address =
       process->ReadPointerFromMemory(address_after_vtable, status);
@@ -144,9 +199,15 @@ CPPLanguageRuntime::FindLibCppStdFunctionCallableInfo(
   if (target.GetSectionLoadList().IsEmpty())
     return optional_info;
 
+  Address vtable_first_entry_resolved;
+
+  if (!target.GetSectionLoadList().ResolveLoadAddress(
+          vtable_address_first_entry, vtable_first_entry_resolved))
+    return optional_info;
+
   Address vtable_addr_resolved;
   SymbolContext sc;
-  Symbol *symbol;
+  Symbol *symbol = nullptr;
 
   if (!target.GetSectionLoadList().ResolveLoadAddress(vtable_address,
                                                       vtable_addr_resolved))
@@ -159,7 +220,7 @@ CPPLanguageRuntime::FindLibCppStdFunctionCallableInfo(
   if (symbol == nullptr)
     return optional_info;
 
-  llvm::StringRef vtable_name(symbol->GetName().GetCString());
+  llvm::StringRef vtable_name(symbol->GetName().GetStringRef());
   bool found_expected_start_string =
       vtable_name.startswith("vtable for std::__1::__function::__func<");
 
@@ -172,6 +233,11 @@ CPPLanguageRuntime::FindLibCppStdFunctionCallableInfo(
   //  ... __func<main::$_0, std::__1::allocator<main::$_0> ...
   //             ^^^^^^^^^
   //
+  // We could see names such as:
+  //    main::$_0
+  //    Bar::add_num2(int)::'lambda'(int)
+  //    Bar
+  //
   // We do this by find the first < and , and extracting in between.
   //
   // This covers the case of the lambda known at compile time.
@@ -193,81 +259,28 @@ CPPLanguageRuntime::FindLibCppStdFunctionCallableInfo(
     symbol = sc.symbol;
   }
 
-  auto get_name = [&first_template_parameter, &symbol]() {
-    // Given case 1:
-    //
-    //    main::$_0
-    //
-    // we want to append ::operator()()
-    if (first_template_parameter.contains("$_"))
-      return llvm::Regex::escape(first_template_parameter.str()) +
-             R"(::operator\(\)\(.*\))";
-
-    if (symbol != nullptr &&
-        symbol->GetName().GetStringRef().contains("__invoke")) {
-
-      llvm::StringRef symbol_name = symbol->GetName().GetStringRef();
-      size_t pos2 = symbol_name.find_last_of(':');
-
-      // Given case 2:
-      //
-      //    main::$_1::__invoke(...)
-      //
-      // We want to slice off __invoke(...) and append operator()()
-      std::string lambda_operator =
-          llvm::Regex::escape(symbol_name.slice(0, pos2 + 1).str()) +
-          R"(operator\(\)\(.*\))";
-
-      return lambda_operator;
-    }
-
-    // Case 3
-    return first_template_parameter.str() + R"(::operator\(\)\(.*\))";
-    ;
+  // These conditions are used several times to simplify statements later on.
+  bool has___invoke =
+      (symbol ? symbol->GetName().GetStringRef().contains("__invoke") : false);
+  auto calculate_symbol_context_helper = [](auto &t,
+                                            SymbolContextList &sc_list) {
+    SymbolContext sc;
+    t->CalculateSymbolContext(&sc);
+    sc_list.Append(sc);
   };
 
-  std::string func_to_match = get_name();
-
-  SymbolContextList scl;
-
-  target.GetImages().FindSymbolsMatchingRegExAndType(
-      RegularExpression{R"(^)" + func_to_match}, eSymbolTypeAny, scl);
+  // Case 2
+  if (has___invoke) {
+    SymbolContextList scl;
+    calculate_symbol_context_helper(symbol, scl);
 
-  // Case 1,2 or 3
-  if (scl.GetSize() >= 1) {
-    SymbolContext sc2 = scl[0];
-
-    AddressRange range;
-    sc2.GetAddressRange(eSymbolContextEverything, 0, false, range);
-
-    Address address = range.GetBaseAddress();
-
-    Address addr;
-    if (target.ResolveLoadAddress(address.GetCallableLoadAddress(&target),
-                                  addr)) {
-      LineEntry line_entry;
-      addr.CalculateSymbolContextLineEntry(line_entry);
-
-      if (first_template_parameter.contains("$_") ||
-          (symbol != nullptr &&
-           symbol->GetName().GetStringRef().contains("__invoke"))) {
-        // Case 1 and 2
-        optional_info.callable_case = LibCppStdFunctionCallableCase::Lambda;
-      } else {
-        // Case 3
-        optional_info.callable_case =
-            LibCppStdFunctionCallableCase::CallableObject;
-      }
-
-      optional_info.callable_symbol = *symbol;
-      optional_info.callable_line_entry = line_entry;
-      optional_info.callable_address = addr;
-      return optional_info;
-    }
+    return line_entry_helper(target, scl[0], symbol, first_template_parameter,
+                             has___invoke);
   }
 
   // Case 4 or 5
-  if (symbol && !symbol->GetName().GetStringRef().startswith("vtable for")) {
+  if (symbol && !symbol->GetName().GetStringRef().startswith("vtable for") &&
+      !contains_lambda_identifier(first_template_parameter) && !has___invoke) {
     optional_info.callable_case =
         LibCppStdFunctionCallableCase::FreeOrMemberFunction;
     optional_info.callable_address = function_address_resolved;
@@ -276,6 +289,50 @@ CPPLanguageRuntime::FindLibCppStdFunctionCallableInfo(
     return optional_info;
   }
 
+  std::string func_to_match = first_template_parameter.str();
+
+  auto it = CallableLookupCache.find(func_to_match);
+  if (it != CallableLookupCache.end())
+    return it->second;
+
+  SymbolContextList scl;
+
+  CompileUnit *vtable_cu =
+      vtable_first_entry_resolved.CalculateSymbolContextCompileUnit();
+  llvm::StringRef name_to_use = func_to_match;
+
+  // Case 3, we have a callable object instead of a lambda
+  //
+  // TODO
+  // We currently don't support this case a callable object may have multiple
+  // operator()() varying on const/non-const and number of arguments and we
+  // don't have a way to currently distinguish them so we will bail out now.
+  if (!contains_lambda_identifier(name_to_use))
+    return optional_info;
+
+  if (vtable_cu && !has___invoke) {
+    lldb::FunctionSP func_sp =
+        vtable_cu->FindFunction([name_to_use](const FunctionSP &f) {
+          auto name = f->GetName().GetStringRef();
+          if (name.startswith(name_to_use) && name.contains("operator"))
+            return true;
+
+          return false;
+        });
+
+    if (func_sp) {
+      calculate_symbol_context_helper(func_sp, scl);
+    }
+  }
+
+  // Case 1 or 3
+  if (scl.GetSize() >= 1) {
+    optional_info = line_entry_helper(target, scl[0], symbol,
+                                      first_template_parameter, has___invoke);
+  }
+
+  CallableLookupCache[func_to_match] = optional_info;
+
   return optional_info;
 }
 
diff --git a/lldb/source/Plugins/LanguageRuntime/CPlusPlus/CPPLanguageRuntime.h b/lldb/source/Plugins/LanguageRuntime/CPlusPlus/CPPLanguageRuntime.h
index 28526361efc4..abdd79fcd7b9 100644
--- a/lldb/source/Plugins/LanguageRuntime/CPlusPlus/CPPLanguageRuntime.h
+++ b/lldb/source/Plugins/LanguageRuntime/CPlusPlus/CPPLanguageRuntime.h
@@ -10,6 +10,9 @@
 #define liblldb_CPPLanguageRuntime_h_
 
 #include <vector>
+
+#include "llvm/ADT/StringMap.h"
+
 #include "lldb/Core/PluginInterface.h"
 #include "lldb/Target/LanguageRuntime.h"
 #include "lldb/lldb-private.h"
@@ -82,6 +85,11 @@ protected:
   CPPLanguageRuntime(Process *process);
 
 private:
+  using OperatorStringToCallableInfoMap =
+    llvm::StringMap<CPPLanguageRuntime::LibCppStdFunctionCallableInfo>;
+
+  OperatorStringToCallableInfoMap CallableLookupCache;
+
   DISALLOW_COPY_AND_ASSIGN(CPPLanguageRuntime);
 };
 
diff --git a/lldb/source/Plugins/LanguageRuntime/CPlusPlus/ItaniumABI/ItaniumABILanguageRuntime.cpp b/lldb/source/Plugins/LanguageRuntime/CPlusPlus/ItaniumABI/ItaniumABILanguageRuntime.cpp
index 02e62a263286..9efb021caa83 100644
--- a/lldb/source/Plugins/LanguageRuntime/CPlusPlus/ItaniumABI/ItaniumABILanguageRuntime.cpp
+++ b/lldb/source/Plugins/LanguageRuntime/CPlusPlus/ItaniumABI/ItaniumABILanguageRuntime.cpp
@@ -537,7 +537,10 @@ ValueObjectSP ItaniumABILanguageRuntime::GetExceptionObjectForThread(
     return {};
 
   ClangASTContext *clang_ast_context =
-      m_process->GetTarget().GetScratchClangASTContext();
+      ClangASTContext::GetScratch(m_process->GetTarget());
+  if (!clang_ast_context)
+    return {};
+
   CompilerType voidstar =
       clang_ast_context->GetBasicType(eBasicTypeVoid).GetPointerType();
 
@@ -559,6 +562,9 @@ ValueObjectSP ItaniumABILanguageRuntime::GetExceptionObjectForThread(
   modules.FindSymbolsWithNameAndType(
       ConstString("__cxa_current_exception_type"), eSymbolTypeCode, contexts);
   contexts.GetContextAtIndex(0, context);
+  if (!context.symbol) {
+    return {};
+  }
   Address addr = context.symbol->GetAddress();
 
   Status error;
diff --git a/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCClassDescriptorV2.cpp b/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCClassDescriptorV2.cpp
index 93aa07f89165..859b693477a9 100644
--- a/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCClassDescriptorV2.cpp
+++ b/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCClassDescriptorV2.cpp
@@ -111,6 +111,18 @@ bool ClassDescriptorV2::class_rw_t::Read(Process *process, lldb::addr_t addr) {
   m_firstSubclass = extractor.GetAddress_unchecked(&cursor);
   m_nextSiblingClass = extractor.GetAddress_unchecked(&cursor);
 
+  if (m_ro_ptr & 1) {
+    DataBufferHeap buffer(ptr_size, '\0');
+    process->ReadMemory(m_ro_ptr ^ 1, buffer.GetBytes(), ptr_size, error);
+    if (error.Fail())
+      return false;
+    cursor = 0;
+    DataExtractor extractor(buffer.GetBytes(), ptr_size,
+                            process->GetByteOrder(),
+                            process->GetAddressByteSize());
+    m_ro_ptr = extractor.GetAddress_unchecked(&cursor);
+  }
+
   return true;
 }
 
diff --git a/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCDeclVendor.cpp b/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCDeclVendor.cpp
index 1f27a4f0b3ed..73843063606c 100644
--- a/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCDeclVendor.cpp
+++ b/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCDeclVendor.cpp
@@ -8,10 +8,9 @@
 
 #include "AppleObjCDeclVendor.h"
 
-#include "Plugins/ExpressionParser/Clang/ASTDumper.h"
 #include "Plugins/LanguageRuntime/ObjC/ObjCLanguageRuntime.h"
 #include "lldb/Core/Module.h"
-#include "lldb/Symbol/ClangExternalASTSourceCommon.h"
+#include "lldb/Symbol/ClangASTMetadata.h"
 #include "lldb/Symbol/ClangUtil.h"
 #include "lldb/Target/Process.h"
 #include "lldb/Target/Target.h"
@@ -19,12 +18,12 @@
 
 #include "clang/AST/ASTContext.h"
 #include "clang/AST/DeclObjC.h"
-
+#include "clang/AST/ExternalASTSource.h"
 
 using namespace lldb_private;
 
 class lldb_private::AppleObjCExternalASTSource
-    : public ClangExternalASTSourceCommon {
+    : public clang::ExternalASTSource {
 public:
   AppleObjCExternalASTSource(AppleObjCDeclVendor &decl_vendor)
       : m_decl_vendor(decl_vendor) {}
@@ -77,24 +76,18 @@ public:
     Log *log(GetLogIfAllCategoriesSet(
         LIBLLDB_LOG_EXPRESSIONS)); // FIXME - a more appropriate log channel?
 
-    if (log) {
-      LLDB_LOGF(log,
-                "AppleObjCExternalASTSource::CompleteType[%u] on "
-                "(ASTContext*)%p Completing (TagDecl*)%p named %s",
-                current_id, static_cast<void *>(&tag_decl->getASTContext()),
-                static_cast<void *>(tag_decl),
-                tag_decl->getName().str().c_str());
+    LLDB_LOGF(log,
+              "AppleObjCExternalASTSource::CompleteType[%u] on "
+              "(ASTContext*)%p Completing (TagDecl*)%p named %s",
+              current_id, static_cast<void *>(&tag_decl->getASTContext()),
+              static_cast<void *>(tag_decl), tag_decl->getName().str().c_str());
 
-      LLDB_LOGF(log, "  AOEAS::CT[%u] Before:", current_id);
-      ASTDumper dumper((clang::Decl *)tag_decl);
-      dumper.ToLog(log, "    [CT] ");
-    }
+    LLDB_LOG(log, "  AOEAS::CT[{0}] Before:\n{1}", current_id,
+             ClangUtil::DumpDecl(tag_decl));
+
+    LLDB_LOG(log, "  AOEAS::CT[{1}] After:{1}", current_id,
+             ClangUtil::DumpDecl(tag_decl));
 
-    if (log) {
-      LLDB_LOGF(log, "  AOEAS::CT[%u] After:", current_id);
-      ASTDumper dumper((clang::Decl *)tag_decl);
-      dumper.ToLog(log, "    [CT] ");
-    }
     return;
   }
 
@@ -115,16 +108,14 @@ public:
                 interface_decl->getName().str().c_str());
 
       LLDB_LOGF(log, "  AOEAS::CT[%u] Before:", current_id);
-      ASTDumper dumper((clang::Decl *)interface_decl);
-      dumper.ToLog(log, "    [CT] ");
+      LLDB_LOG(log, "    [CT] {0}", ClangUtil::DumpDecl(interface_decl));
     }
 
     m_decl_vendor.FinishDecl(interface_decl);
 
     if (log) {
       LLDB_LOGF(log, "  [CT] After:");
-      ASTDumper dumper((clang::Decl *)interface_decl);
-      dumper.ToLog(log, "    [CT] ");
+      LLDB_LOG(log, "    [CT] {0}", ClangUtil::DumpDecl(interface_decl));
     }
     return;
   }
@@ -141,7 +132,7 @@ public:
 
   void StartTranslationUnit(clang::ASTConsumer *Consumer) override {
     clang::TranslationUnitDecl *translation_unit_decl =
-        m_decl_vendor.m_ast_ctx.getASTContext()->getTranslationUnitDecl();
+        m_decl_vendor.m_ast_ctx.getASTContext().getTranslationUnitDecl();
     translation_unit_decl->setHasExternalVisibleStorage();
     translation_unit_decl->setHasExternalLexicalStorage();
   }
@@ -155,14 +146,12 @@ AppleObjCDeclVendor::AppleObjCDeclVendor(ObjCLanguageRuntime &runtime)
       m_ast_ctx(runtime.GetProcess()
                     ->GetTarget()
                     .GetArchitecture()
-                    .GetTriple()
-                    .getTriple()
-                    .c_str()),
+                    .GetTriple()),
       m_type_realizer_sp(m_runtime.GetEncodingToType()) {
   m_external_source = new AppleObjCExternalASTSource(*this);
   llvm::IntrusiveRefCntPtr<clang::ExternalASTSource> external_source_owning_ptr(
       m_external_source);
-  m_ast_ctx.getASTContext()->setExternalSource(external_source_owning_ptr);
+  m_ast_ctx.getASTContext().setExternalSource(external_source_owning_ptr);
 }
 
 clang::ObjCInterfaceDecl *
@@ -172,7 +161,7 @@ AppleObjCDeclVendor::GetDeclForISA(ObjCLanguageRuntime::ObjCISA isa) {
   if (iter != m_isa_to_interface.end())
     return iter->second;
 
-  clang::ASTContext *ast_ctx = m_ast_ctx.getASTContext();
+  clang::ASTContext &ast_ctx = m_ast_ctx.getASTContext();
 
   ObjCLanguageRuntime::ClassDescriptorSP descriptor =
       m_runtime.GetClassDescriptorFromISA(isa);
@@ -183,20 +172,20 @@ AppleObjCDeclVendor::GetDeclForISA(ObjCLanguageRuntime::ObjCISA isa) {
   ConstString name(descriptor->GetClassName());
 
   clang::IdentifierInfo &identifier_info =
-      ast_ctx->Idents.get(name.GetStringRef());
+      ast_ctx.Idents.get(name.GetStringRef());
 
   clang::ObjCInterfaceDecl *new_iface_decl = clang::ObjCInterfaceDecl::Create(
-      *ast_ctx, ast_ctx->getTranslationUnitDecl(), clang::SourceLocation(),
+      ast_ctx, ast_ctx.getTranslationUnitDecl(), clang::SourceLocation(),
       &identifier_info, nullptr, nullptr);
 
   ClangASTMetadata meta_data;
   meta_data.SetISAPtr(isa);
-  m_external_source->SetMetadata(new_iface_decl, meta_data);
+  m_ast_ctx.SetMetadata(new_iface_decl, meta_data);
 
   new_iface_decl->setHasExternalVisibleStorage();
   new_iface_decl->setHasExternalLexicalStorage();
 
-  ast_ctx->getTranslationUnitDecl()->addDecl(new_iface_decl);
+  ast_ctx.getTranslationUnitDecl()->addDecl(new_iface_decl);
 
   m_isa_to_interface[isa] = new_iface_decl;
 
@@ -320,7 +309,8 @@ public:
   }
 
   clang::ObjCMethodDecl *
-  BuildMethod(clang::ObjCInterfaceDecl *interface_decl, const char *name,
+  BuildMethod(ClangASTContext &clang_ast_ctxt,
+              clang::ObjCInterfaceDecl *interface_decl, const char *name,
               bool instance,
               ObjCLanguageRuntime::EncodingToTypeSP type_realizer_sp) {
     if (!m_is_valid || m_type_vector.size() < 3)
@@ -330,7 +320,8 @@ public:
 
     const bool isInstance = instance;
     const bool isVariadic = false;
-    const bool isSynthesized = false;
+    const bool isPropertyAccessor = false;
+    const bool isSynthesizedAccessorStub = false;
     const bool isImplicitlyDeclared = true;
     const bool isDefined = false;
     const clang::ObjCMethodDecl::ImplementationControl impControl =
@@ -368,8 +359,7 @@ public:
 
     clang::QualType ret_type =
         ClangUtil::GetQualType(type_realizer_sp->RealizeType(
-            interface_decl->getASTContext(), m_type_vector[0].c_str(),
-            for_expression));
+            clang_ast_ctxt, m_type_vector[0].c_str(), for_expression));
 
     if (ret_type.isNull())
       return nullptr;
@@ -377,8 +367,8 @@ public:
     clang::ObjCMethodDecl *ret = clang::ObjCMethodDecl::Create(
         ast_ctx, clang::SourceLocation(), clang::SourceLocation(), sel,
         ret_type, nullptr, interface_decl, isInstance, isVariadic,
-        isSynthesized, isImplicitlyDeclared, isDefined, impControl,
-        HasRelatedResultType);
+        isPropertyAccessor, isSynthesizedAccessorStub, isImplicitlyDeclared,
+        isDefined, impControl, HasRelatedResultType);
 
     std::vector<clang::ParmVarDecl *> parm_vars;
 
@@ -386,7 +376,7 @@ public:
       const bool for_expression = true;
       clang::QualType arg_type =
           ClangUtil::GetQualType(type_realizer_sp->RealizeType(
-              ast_ctx, m_type_vector[ai].c_str(), for_expression));
+              clang_ast_ctxt, m_type_vector[ai].c_str(), for_expression));
 
       if (arg_type.isNull())
         return nullptr; // well, we just wasted a bunch of time.  Wish we could
@@ -421,7 +411,7 @@ bool AppleObjCDeclVendor::FinishDecl(clang::ObjCInterfaceDecl *interface_decl) {
   Log *log(GetLogIfAllCategoriesSet(
       LIBLLDB_LOG_EXPRESSIONS)); // FIXME - a more appropriate log channel?
 
-  ClangASTMetadata *metadata = m_external_source->GetMetadata(interface_decl);
+  ClangASTMetadata *metadata = m_ast_ctx.GetMetadata(interface_decl);
   ObjCLanguageRuntime::ObjCISA objc_isa = 0;
   if (metadata)
     objc_isa = metadata->GetISAPtr();
@@ -451,9 +441,9 @@ bool AppleObjCDeclVendor::FinishDecl(clang::ObjCInterfaceDecl *interface_decl) {
       return;
 
     FinishDecl(superclass_decl);
-    clang::ASTContext *context = m_ast_ctx.getASTContext();
-    interface_decl->setSuperClass(context->getTrivialTypeSourceInfo(
-        context->getObjCInterfaceType(superclass_decl)));
+    clang::ASTContext &context = m_ast_ctx.getASTContext();
+    interface_decl->setSuperClass(context.getTrivialTypeSourceInfo(
+        context.getObjCInterfaceType(superclass_decl)));
   };
 
   auto instance_method_func =
@@ -463,8 +453,8 @@ bool AppleObjCDeclVendor::FinishDecl(clang::ObjCInterfaceDecl *interface_decl) {
 
     ObjCRuntimeMethodType method_type(types);
 
-    clang::ObjCMethodDecl *method_decl =
-        method_type.BuildMethod(interface_decl, name, true, m_type_realizer_sp);
+    clang::ObjCMethodDecl *method_decl = method_type.BuildMethod(
+        m_ast_ctx, interface_decl, name, true, m_type_realizer_sp);
 
     LLDB_LOGF(log, "[  AOTV::FD] Instance method [%s] [%s]", name, types);
 
@@ -482,7 +472,7 @@ bool AppleObjCDeclVendor::FinishDecl(clang::ObjCInterfaceDecl *interface_decl) {
     ObjCRuntimeMethodType method_type(types);
 
     clang::ObjCMethodDecl *method_decl = method_type.BuildMethod(
-        interface_decl, name, false, m_type_realizer_sp);
+        m_ast_ctx, interface_decl, name, false, m_type_realizer_sp);
 
     LLDB_LOGF(log, "[  AOTV::FD] Class method [%s] [%s]", name, types);
 
@@ -511,8 +501,8 @@ bool AppleObjCDeclVendor::FinishDecl(clang::ObjCInterfaceDecl *interface_decl) {
       clang::TypeSourceInfo *const type_source_info = nullptr;
       const bool is_synthesized = false;
       clang::ObjCIvarDecl *ivar_decl = clang::ObjCIvarDecl::Create(
-          *m_ast_ctx.getASTContext(), interface_decl, clang::SourceLocation(),
-          clang::SourceLocation(), &m_ast_ctx.getASTContext()->Idents.get(name),
+          m_ast_ctx.getASTContext(), interface_decl, clang::SourceLocation(),
+          clang::SourceLocation(), &m_ast_ctx.getASTContext().Idents.get(name),
           ClangUtil::GetQualType(ivar_type),
           type_source_info, // TypeSourceInfo *
           clang::ObjCIvarDecl::Public, nullptr, is_synthesized);
@@ -525,36 +515,29 @@ bool AppleObjCDeclVendor::FinishDecl(clang::ObjCInterfaceDecl *interface_decl) {
     return false;
   };
 
-  if (log) {
-    ASTDumper method_dumper((clang::Decl *)interface_decl);
-
-    LLDB_LOGF(log,
-              "[AppleObjCDeclVendor::FinishDecl] Finishing Objective-C "
-              "interface for %s",
-              descriptor->GetClassName().AsCString());
-  }
+  LLDB_LOG(log,
+           "[AppleObjCDeclVendor::FinishDecl] Finishing Objective-C "
+           "interface for %s",
+           descriptor->GetClassName().AsCString());
 
   if (!descriptor->Describe(superclass_func, instance_method_func,
                             class_method_func, ivar_func))
     return false;
 
   if (log) {
-    ASTDumper method_dumper((clang::Decl *)interface_decl);
-
     LLDB_LOGF(
         log,
         "[AppleObjCDeclVendor::FinishDecl] Finished Objective-C interface");
 
-    method_dumper.ToLog(log, "  [AOTV::FD] ");
+    LLDB_LOG(log, "  [AOTV::FD] {0}", ClangUtil::DumpDecl(interface_decl));
   }
 
   return true;
 }
 
-uint32_t
-AppleObjCDeclVendor::FindDecls(ConstString name, bool append,
-                               uint32_t max_matches,
-                               std::vector<clang::NamedDecl *> &decls) {
+uint32_t AppleObjCDeclVendor::FindDecls(ConstString name, bool append,
+                                        uint32_t max_matches,
+                                        std::vector<CompilerDecl> &decls) {
   static unsigned int invocation_id = 0;
   unsigned int current_id = invocation_id++;
 
@@ -573,37 +556,35 @@ AppleObjCDeclVendor::FindDecls(ConstString name, bool append,
   do {
     // See if the type is already in our ASTContext.
 
-    clang::ASTContext *ast_ctx = m_ast_ctx.getASTContext();
+    clang::ASTContext &ast_ctx = m_ast_ctx.getASTContext();
 
     clang::IdentifierInfo &identifier_info =
-        ast_ctx->Idents.get(name.GetStringRef());
+        ast_ctx.Idents.get(name.GetStringRef());
     clang::DeclarationName decl_name =
-        ast_ctx->DeclarationNames.getIdentifier(&identifier_info);
+        ast_ctx.DeclarationNames.getIdentifier(&identifier_info);
 
     clang::DeclContext::lookup_result lookup_result =
-        ast_ctx->getTranslationUnitDecl()->lookup(decl_name);
+        ast_ctx.getTranslationUnitDecl()->lookup(decl_name);
 
     if (!lookup_result.empty()) {
       if (clang::ObjCInterfaceDecl *result_iface_decl =
               llvm::dyn_cast<clang::ObjCInterfaceDecl>(lookup_result[0])) {
         if (log) {
           clang::QualType result_iface_type =
-              ast_ctx->getObjCInterfaceType(result_iface_decl);
-          ASTDumper dumper(result_iface_type);
+              ast_ctx.getObjCInterfaceType(result_iface_decl);
 
           uint64_t isa_value = LLDB_INVALID_ADDRESS;
-          ClangASTMetadata *metadata =
-              m_external_source->GetMetadata(result_iface_decl);
+          ClangASTMetadata *metadata = m_ast_ctx.GetMetadata(result_iface_decl);
           if (metadata)
             isa_value = metadata->GetISAPtr();
 
-          LLDB_LOGF(log,
-                    "AOCTV::FT [%u] Found %s (isa 0x%" PRIx64
-                    ") in the ASTContext",
-                    current_id, dumper.GetCString(), isa_value);
+          LLDB_LOG(log,
+                   "AOCTV::FT [%u] Found %s (isa 0x%" PRIx64
+                   ") in the ASTContext",
+                   current_id, result_iface_type.getAsString(), isa_value);
         }
 
-        decls.push_back(result_iface_decl);
+        decls.push_back(CompilerDecl(&m_ast_ctx, result_iface_decl));
         ret++;
         break;
       } else {
@@ -640,24 +621,16 @@ AppleObjCDeclVendor::FindDecls(ConstString name, bool append,
     }
 
     if (log) {
-      clang::QualType new_iface_type =
-          ast_ctx->getObjCInterfaceType(iface_decl);
-      ASTDumper dumper(new_iface_type);
-      LLDB_LOGF(log, "AOCTV::FT [%u] Created %s (isa 0x%" PRIx64 ")",
-                current_id, dumper.GetCString(), (uint64_t)isa);
+      clang::QualType new_iface_type = ast_ctx.getObjCInterfaceType(iface_decl);
+
+      LLDB_LOG(log, "AOCTV::FT [{0}] Created {1} (isa 0x{2:x})", current_id,
+               new_iface_type.getAsString(), (uint64_t)isa);
     }
 
-    decls.push_back(iface_decl);
+    decls.push_back(CompilerDecl(&m_ast_ctx, iface_decl));
     ret++;
     break;
   } while (false);
 
   return ret;
 }
-
-clang::ExternalASTMerger::ImporterSource
-AppleObjCDeclVendor::GetImporterSource() {
-  return clang::ExternalASTMerger::ImporterSource(*m_ast_ctx.getASTContext(),
-                                                  *m_ast_ctx.getFileManager(),
-                                                  m_ast_ctx.GetOriginMap());
-}
diff --git a/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCDeclVendor.h b/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCDeclVendor.h
index 99ca4b748709..f49ca3540c2c 100644
--- a/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCDeclVendor.h
+++ b/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCDeclVendor.h
@@ -28,9 +28,7 @@ public:
   }
 
   uint32_t FindDecls(ConstString name, bool append, uint32_t max_matches,
-                     std::vector<clang::NamedDecl *> &decls) override;
-
-  clang::ExternalASTMerger::ImporterSource GetImporterSource() override;
+                     std::vector<CompilerDecl> &decls) override;
 
   friend class AppleObjCExternalASTSource;
 
diff --git a/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntime.cpp b/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntime.cpp
index 8ca9ad7b843a..7076959bee97 100644
--- a/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntime.cpp
+++ b/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntime.cpp
@@ -111,7 +111,10 @@ bool AppleObjCRuntime::GetObjectDescription(Stream &strm, Value &value,
     }
   } else {
     // If it is not a pointer, see if we can make it into a pointer.
-    ClangASTContext *ast_context = target->GetScratchClangASTContext();
+    ClangASTContext *ast_context = ClangASTContext::GetScratch(*target);
+    if (!ast_context)
+      return false;
+
     CompilerType opaque_type = ast_context->GetBasicType(eBasicTypeObjCID);
     if (!opaque_type)
       opaque_type = ast_context->GetBasicType(eBasicTypeVoid).GetPointerType();
@@ -123,7 +126,9 @@ bool AppleObjCRuntime::GetObjectDescription(Stream &strm, Value &value,
   arg_value_list.PushValue(value);
 
   // This is the return value:
-  ClangASTContext *ast_context = target->GetScratchClangASTContext();
+  ClangASTContext *ast_context = ClangASTContext::GetScratch(*target);
+  if (!ast_context)
+    return false;
 
   CompilerType return_compiler_type = ast_context->GetCStringType(true);
   Value ret;
@@ -494,9 +499,12 @@ ThreadSP AppleObjCRuntime::GetBacktraceThreadFromException(
   reserved_dict = reserved_dict->GetSyntheticValue();
   if (!reserved_dict) return ThreadSP();
 
+  ClangASTContext *clang_ast_context =
+      ClangASTContext::GetScratch(*exception_sp->GetTargetSP());
+  if (!clang_ast_context)
+    return ThreadSP();
   CompilerType objc_id =
-      exception_sp->GetTargetSP()->GetScratchClangASTContext()->GetBasicType(
-          lldb::eBasicTypeObjCID);
+      clang_ast_context->GetBasicType(lldb::eBasicTypeObjCID);
   ValueObjectSP return_addresses;
 
   auto objc_object_from_address = [&exception_sp, &objc_id](uint64_t addr,
diff --git a/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntimeV2.cpp b/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntimeV2.cpp
index 9bdbef393e39..4015f10c4966 100644
--- a/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntimeV2.cpp
+++ b/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntimeV2.cpp
@@ -1301,7 +1301,7 @@ AppleObjCRuntimeV2::UpdateISAToDescriptorMapDynamic(
     return DescriptorMapUpdateResult::Fail();
 
   thread_sp->CalculateExecutionContext(exe_ctx);
-  ClangASTContext *ast = process->GetTarget().GetScratchClangASTContext();
+  ClangASTContext *ast = ClangASTContext::GetScratch(process->GetTarget());
 
   if (!ast)
     return DescriptorMapUpdateResult::Fail();
@@ -1563,7 +1563,7 @@ AppleObjCRuntimeV2::UpdateISAToDescriptorMapSharedCache() {
     return DescriptorMapUpdateResult::Fail();
 
   thread_sp->CalculateExecutionContext(exe_ctx);
-  ClangASTContext *ast = process->GetTarget().GetScratchClangASTContext();
+  ClangASTContext *ast = ClangASTContext::GetScratch(process->GetTarget());
 
   if (!ast)
     return DescriptorMapUpdateResult::Fail();
@@ -1625,19 +1625,13 @@ AppleObjCRuntimeV2::UpdateISAToDescriptorMapSharedCache() {
     // Substitute in the correct class_getName / class_getNameRaw function name,
     // concatenate the two parts of our expression text.  The format string
     // has two %s's, so provide the name twice.
-    int prefix_string_size = snprintf (nullptr, 0, 
+    std::string shared_class_expression;
+    llvm::raw_string_ostream(shared_class_expression) << llvm::format(
                                g_shared_cache_class_name_funcptr,
                                class_name_getter_function_name.AsCString(),
                                class_name_getter_function_name.AsCString());
 
-    char *class_name_func_ptr_expr = (char*) malloc (prefix_string_size + 1);
-    snprintf (class_name_func_ptr_expr, prefix_string_size + 1,
-              g_shared_cache_class_name_funcptr,
-              class_name_getter_function_name.AsCString(),
-              class_name_getter_function_name.AsCString());
-    std::string shared_class_expression = class_name_func_ptr_expr;
     shared_class_expression += g_get_shared_cache_class_info_body;
-    free (class_name_func_ptr_expr);
 
     m_get_shared_cache_class_info_code.reset(
         GetTargetRef().GetUtilityFunctionForLanguage(
@@ -1984,36 +1978,6 @@ void AppleObjCRuntimeV2::WarnIfNoClassesCached(
   }
 }
 
-ConstString
-AppleObjCRuntimeV2::GetActualTypeName(ObjCLanguageRuntime::ObjCISA isa) {
-  if (isa == g_objc_Tagged_ISA) {
-    static const ConstString g_objc_tagged_isa_name("_lldb_Tagged_ObjC_ISA");
-    return g_objc_tagged_isa_name;
-  }
-  if (isa == g_objc_Tagged_ISA_NSAtom) {
-    static const ConstString g_objc_tagged_isa_nsatom_name("NSAtom");
-    return g_objc_tagged_isa_nsatom_name;
-  }
-  if (isa == g_objc_Tagged_ISA_NSNumber) {
-    static const ConstString g_objc_tagged_isa_nsnumber_name("NSNumber");
-    return g_objc_tagged_isa_nsnumber_name;
-  }
-  if (isa == g_objc_Tagged_ISA_NSDateTS) {
-    static const ConstString g_objc_tagged_isa_nsdatets_name("NSDateTS");
-    return g_objc_tagged_isa_nsdatets_name;
-  }
-  if (isa == g_objc_Tagged_ISA_NSManagedObject) {
-    static const ConstString g_objc_tagged_isa_nsmanagedobject_name(
-        "NSManagedObject");
-    return g_objc_tagged_isa_nsmanagedobject_name;
-  }
-  if (isa == g_objc_Tagged_ISA_NSDate) {
-    static const ConstString g_objc_tagged_isa_nsdate_name("NSDate");
-    return g_objc_tagged_isa_nsdate_name;
-  }
-  return ObjCLanguageRuntime::GetActualTypeName(isa);
-}
-
 DeclVendor *AppleObjCRuntimeV2::GetDeclVendor() {
   if (!m_decl_vendor_up)
     m_decl_vendor_up.reset(new AppleObjCDeclVendor(*this));
@@ -2678,10 +2642,12 @@ class ObjCExceptionRecognizedStackFrame : public RecognizedStackFrame {
     const lldb::ABISP &abi = process_sp->GetABI();
     if (!abi) return;
 
-    CompilerType voidstar = process_sp->GetTarget()
-                                .GetScratchClangASTContext()
-                                ->GetBasicType(lldb::eBasicTypeVoid)
-                                .GetPointerType();
+    ClangASTContext *clang_ast_context =
+        ClangASTContext::GetScratch(process_sp->GetTarget());
+    if (!clang_ast_context)
+      return;
+    CompilerType voidstar =
+        clang_ast_context->GetBasicType(lldb::eBasicTypeVoid).GetPointerType();
 
     ValueList args;
     Value input_value;
@@ -2699,7 +2665,7 @@ class ObjCExceptionRecognizedStackFrame : public RecognizedStackFrame {
     exception = ValueObjectRecognizerSynthesizedValue::Create(
         *exception, eValueTypeVariableArgument);
     exception = exception->GetDynamicValue(eDynamicDontRunTarget);
-      
+
     m_arguments = ValueObjectListSP(new ValueObjectList());
     m_arguments->Append(exception);
   }
diff --git a/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntimeV2.h b/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntimeV2.h
index a0fd39dc03b2..785bb3938d2c 100644
--- a/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntimeV2.h
+++ b/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntimeV2.h
@@ -69,8 +69,6 @@ public:
 
   void UpdateISAToDescriptorMapIfNeeded() override;
 
-  ConstString GetActualTypeName(ObjCLanguageRuntime::ObjCISA isa) override;
-
   ClassDescriptorSP GetClassDescriptor(ValueObject &in_value) override;
 
   ClassDescriptorSP GetClassDescriptorFromISA(ObjCISA isa) override;
diff --git a/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCTrampolineHandler.cpp b/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCTrampolineHandler.cpp
index 379ef3dca86c..36f95c063b81 100644
--- a/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCTrampolineHandler.cpp
+++ b/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCTrampolineHandler.cpp
@@ -522,7 +522,10 @@ bool AppleObjCTrampolineHandler::AppleObjCVTables::RefreshTrampolines(
     const ABI *abi = process->GetABI().get();
 
     ClangASTContext *clang_ast_context =
-        process->GetTarget().GetScratchClangASTContext();
+        ClangASTContext::GetScratch(process->GetTarget());
+    if (!clang_ast_context)
+      return false;
+
     ValueList argument_values;
     Value input_value;
     CompilerType clang_void_ptr_type =
@@ -802,7 +805,10 @@ AppleObjCTrampolineHandler::SetupDispatchFunction(Thread &thread,
 
       // Next make the runner function for our implementation utility function.
       ClangASTContext *clang_ast_context =
-          thread.GetProcess()->GetTarget().GetScratchClangASTContext();
+          ClangASTContext::GetScratch(thread.GetProcess()->GetTarget());
+      if (!clang_ast_context)
+        return LLDB_INVALID_ADDRESS;
+
       CompilerType clang_void_ptr_type =
           clang_ast_context->GetBasicType(eBasicTypeVoid).GetPointerType();
       Status error;
@@ -895,7 +901,10 @@ AppleObjCTrampolineHandler::GetStepThroughDispatchPlan(Thread &thread,
 
     TargetSP target_sp(thread.CalculateTarget());
 
-    ClangASTContext *clang_ast_context = target_sp->GetScratchClangASTContext();
+    ClangASTContext *clang_ast_context = ClangASTContext::GetScratch(*target_sp);
+    if (!clang_ast_context)
+      return ret_plan_sp;
+
     ValueList argument_values;
     Value void_ptr_value;
     CompilerType clang_void_ptr_type =
diff --git a/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCTypeEncodingParser.cpp b/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCTypeEncodingParser.cpp
index 6402e80d6f98..66f04bef6cbd 100644
--- a/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCTypeEncodingParser.cpp
+++ b/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCTypeEncodingParser.cpp
@@ -26,9 +26,7 @@ AppleObjCTypeEncodingParser::AppleObjCTypeEncodingParser(
     m_scratch_ast_ctx_up.reset(new ClangASTContext(runtime.GetProcess()
                                                        ->GetTarget()
                                                        .GetArchitecture()
-                                                       .GetTriple()
-                                                       .str()
-                                                       .c_str()));
+                                                       .GetTriple()));
 }
 
 std::string AppleObjCTypeEncodingParser::ReadStructName(StringLexer &type) {
@@ -63,7 +61,7 @@ AppleObjCTypeEncodingParser::StructElement::StructElement()
     : name(""), type(clang::QualType()), bitfield(0) {}
 
 AppleObjCTypeEncodingParser::StructElement
-AppleObjCTypeEncodingParser::ReadStructElement(clang::ASTContext &ast_ctx,
+AppleObjCTypeEncodingParser::ReadStructElement(ClangASTContext &ast_ctx,
                                                StringLexer &type,
                                                bool for_expression) {
   StructElement retval;
@@ -78,19 +76,19 @@ AppleObjCTypeEncodingParser::ReadStructElement(clang::ASTContext &ast_ctx,
 }
 
 clang::QualType AppleObjCTypeEncodingParser::BuildStruct(
-    clang::ASTContext &ast_ctx, StringLexer &type, bool for_expression) {
+    ClangASTContext &ast_ctx, StringLexer &type, bool for_expression) {
   return BuildAggregate(ast_ctx, type, for_expression, '{', '}',
                         clang::TTK_Struct);
 }
 
 clang::QualType AppleObjCTypeEncodingParser::BuildUnion(
-    clang::ASTContext &ast_ctx, StringLexer &type, bool for_expression) {
+    ClangASTContext &ast_ctx, StringLexer &type, bool for_expression) {
   return BuildAggregate(ast_ctx, type, for_expression, '(', ')',
                         clang::TTK_Union);
 }
 
 clang::QualType AppleObjCTypeEncodingParser::BuildAggregate(
-    clang::ASTContext &ast_ctx, StringLexer &type, bool for_expression,
+    ClangASTContext &ast_ctx, StringLexer &type, bool for_expression,
     char opener, char closer, uint32_t kind) {
   if (!type.NextIf(opener))
     return clang::QualType();
@@ -124,11 +122,8 @@ clang::QualType AppleObjCTypeEncodingParser::BuildAggregate(
   if (is_templated)
     return clang::QualType(); // This is where we bail out.  Sorry!
 
-  ClangASTContext *lldb_ctx = ClangASTContext::GetASTContext(&ast_ctx);
-  if (!lldb_ctx)
-    return clang::QualType();
-  CompilerType union_type(lldb_ctx->CreateRecordType(
-      nullptr, lldb::eAccessPublic, name.c_str(), kind, lldb::eLanguageTypeC));
+  CompilerType union_type(ast_ctx.CreateRecordType(
+      nullptr, lldb::eAccessPublic, name, kind, lldb::eLanguageTypeC));
   if (union_type) {
     ClangASTContext::StartTagDeclarationDefinition(union_type);
 
@@ -140,9 +135,7 @@ clang::QualType AppleObjCTypeEncodingParser::BuildAggregate(
         element.name = elem_name.GetString();
       }
       ClangASTContext::AddFieldToRecordType(
-          union_type, element.name.c_str(),
-          CompilerType(ClangASTContext::GetASTContext(&ast_ctx),
-                       element.type.getAsOpaquePtr()),
+          union_type, element.name.c_str(), ast_ctx.GetType(element.type),
           lldb::eAccessPublic, element.bitfield);
       ++count;
     }
@@ -152,20 +145,15 @@ clang::QualType AppleObjCTypeEncodingParser::BuildAggregate(
 }
 
 clang::QualType AppleObjCTypeEncodingParser::BuildArray(
-    clang::ASTContext &ast_ctx, StringLexer &type, bool for_expression) {
+    ClangASTContext &ast_ctx, StringLexer &type, bool for_expression) {
   if (!type.NextIf('['))
     return clang::QualType();
   uint32_t size = ReadNumber(type);
   clang::QualType element_type(BuildType(ast_ctx, type, for_expression));
   if (!type.NextIf(']'))
     return clang::QualType();
-  ClangASTContext *lldb_ctx = ClangASTContext::GetASTContext(&ast_ctx);
-  if (!lldb_ctx)
-    return clang::QualType();
-  CompilerType array_type(lldb_ctx->CreateArrayType(
-      CompilerType(ClangASTContext::GetASTContext(&ast_ctx),
-                   element_type.getAsOpaquePtr()),
-      size, false));
+  CompilerType array_type(ast_ctx.CreateArrayType(
+      CompilerType(&ast_ctx, element_type.getAsOpaquePtr()), size, false));
   return ClangUtil::GetQualType(array_type);
 }
 
@@ -175,10 +163,12 @@ clang::QualType AppleObjCTypeEncodingParser::BuildArray(
 // consume but ignore the type info and always return an 'id'; if anything,
 // dynamic typing will resolve things for us anyway
 clang::QualType AppleObjCTypeEncodingParser::BuildObjCObjectPointerType(
-    clang::ASTContext &ast_ctx, StringLexer &type, bool for_expression) {
+    ClangASTContext &clang_ast_ctx, StringLexer &type, bool for_expression) {
   if (!type.NextIf('@'))
     return clang::QualType();
 
+  clang::ASTContext &ast_ctx = clang_ast_ctx.getASTContext();
+
   std::string name;
 
   if (type.NextIf('"')) {
@@ -257,23 +247,25 @@ clang::QualType AppleObjCTypeEncodingParser::BuildObjCObjectPointerType(
 }
 
 clang::QualType
-AppleObjCTypeEncodingParser::BuildType(clang::ASTContext &ast_ctx,
+AppleObjCTypeEncodingParser::BuildType(ClangASTContext &clang_ast_ctx,
                                        StringLexer &type, bool for_expression,
                                        uint32_t *bitfield_bit_size) {
   if (!type.HasAtLeast(1))
     return clang::QualType();
 
+  clang::ASTContext &ast_ctx = clang_ast_ctx.getASTContext();
+
   switch (type.Peek()) {
   default:
     break;
   case '{':
-    return BuildStruct(ast_ctx, type, for_expression);
+    return BuildStruct(clang_ast_ctx, type, for_expression);
   case '[':
-    return BuildArray(ast_ctx, type, for_expression);
+    return BuildArray(clang_ast_ctx, type, for_expression);
   case '(':
-    return BuildUnion(ast_ctx, type, for_expression);
+    return BuildUnion(clang_ast_ctx, type, for_expression);
   case '@':
-    return BuildObjCObjectPointerType(ast_ctx, type, for_expression);
+    return BuildObjCObjectPointerType(clang_ast_ctx, type, for_expression);
   }
 
   switch (type.Next()) {
@@ -289,10 +281,7 @@ AppleObjCTypeEncodingParser::BuildType(clang::ASTContext &ast_ctx,
   case 'l':
     return ast_ctx.getIntTypeForBitwidth(32, true);
   // this used to be done like this:
-  //   ClangASTContext *lldb_ctx = ClangASTContext::GetASTContext(&ast_ctx);
-  //   if (!lldb_ctx)
-  //      return clang::QualType();
-  //   return lldb_ctx->GetIntTypeFromBitSize(32, true).GetQualType();
+  //   return clang_ast_ctx->GetIntTypeFromBitSize(32, true).GetQualType();
   // which uses one of the constants if one is available, but we don't think
   // all this work is necessary.
   case 'q':
@@ -331,7 +320,8 @@ AppleObjCTypeEncodingParser::BuildType(clang::ASTContext &ast_ctx,
       return clang::QualType();
   }
   case 'r': {
-    clang::QualType target_type = BuildType(ast_ctx, type, for_expression);
+    clang::QualType target_type =
+        BuildType(clang_ast_ctx, type, for_expression);
     if (target_type.isNull())
       return clang::QualType();
     else if (target_type == ast_ctx.UnknownAnyTy)
@@ -348,7 +338,8 @@ AppleObjCTypeEncodingParser::BuildType(clang::ASTContext &ast_ctx,
       // practical cases
       return ast_ctx.VoidPtrTy;
     } else {
-      clang::QualType target_type = BuildType(ast_ctx, type, for_expression);
+      clang::QualType target_type =
+          BuildType(clang_ast_ctx, type, for_expression);
       if (target_type.isNull())
         return clang::QualType();
       else if (target_type == ast_ctx.UnknownAnyTy)
@@ -362,13 +353,13 @@ AppleObjCTypeEncodingParser::BuildType(clang::ASTContext &ast_ctx,
   }
 }
 
-CompilerType AppleObjCTypeEncodingParser::RealizeType(
-    clang::ASTContext &ast_ctx, const char *name, bool for_expression) {
+CompilerType AppleObjCTypeEncodingParser::RealizeType(ClangASTContext &ast_ctx,
+                                                      const char *name,
+                                                      bool for_expression) {
   if (name && name[0]) {
     StringLexer lexer(name);
     clang::QualType qual_type = BuildType(ast_ctx, lexer, for_expression);
-    return CompilerType(ClangASTContext::GetASTContext(&ast_ctx),
-                        qual_type.getAsOpaquePtr());
+    return ast_ctx.GetType(qual_type);
   }
   return CompilerType();
 }
diff --git a/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCTypeEncodingParser.h b/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCTypeEncodingParser.h
index 590bc4ba9eae..e43711bf4ee4 100644
--- a/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCTypeEncodingParser.h
+++ b/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCTypeEncodingParser.h
@@ -22,7 +22,7 @@ public:
   AppleObjCTypeEncodingParser(ObjCLanguageRuntime &runtime);
   ~AppleObjCTypeEncodingParser() override = default;
 
-  CompilerType RealizeType(clang::ASTContext &ast_ctx, const char *name,
+  CompilerType RealizeType(ClangASTContext &ast_ctx, const char *name,
                            bool for_expression) override;
 
 private:
@@ -35,29 +35,29 @@ private:
     ~StructElement() = default;
   };
 
-  clang::QualType BuildType(clang::ASTContext &ast_ctx, StringLexer &type,
+  clang::QualType BuildType(ClangASTContext &clang_ast_ctx, StringLexer &type,
                             bool for_expression,
                             uint32_t *bitfield_bit_size = nullptr);
 
-  clang::QualType BuildStruct(clang::ASTContext &ast_ctx, StringLexer &type,
+  clang::QualType BuildStruct(ClangASTContext &ast_ctx, StringLexer &type,
                               bool for_expression);
 
-  clang::QualType BuildAggregate(clang::ASTContext &ast_ctx, StringLexer &type,
-                                 bool for_expression, char opener, char closer,
-                                 uint32_t kind);
+  clang::QualType BuildAggregate(ClangASTContext &clang_ast_ctx,
+                                 StringLexer &type, bool for_expression,
+                                 char opener, char closer, uint32_t kind);
 
-  clang::QualType BuildUnion(clang::ASTContext &ast_ctx, StringLexer &type,
+  clang::QualType BuildUnion(ClangASTContext &ast_ctx, StringLexer &type,
                              bool for_expression);
 
-  clang::QualType BuildArray(clang::ASTContext &ast_ctx, StringLexer &type,
+  clang::QualType BuildArray(ClangASTContext &ast_ctx, StringLexer &type,
                              bool for_expression);
 
   std::string ReadStructName(StringLexer &type);
 
-  StructElement ReadStructElement(clang::ASTContext &ast_ctx, StringLexer &type,
+  StructElement ReadStructElement(ClangASTContext &ast_ctx, StringLexer &type,
                                   bool for_expression);
 
-  clang::QualType BuildObjCObjectPointerType(clang::ASTContext &ast_ctx,
+  clang::QualType BuildObjCObjectPointerType(ClangASTContext &clang_ast_ctx,
                                              StringLexer &type,
                                              bool for_expression);
 
diff --git a/lldb/source/Plugins/LanguageRuntime/ObjC/ObjCLanguageRuntime.cpp b/lldb/source/Plugins/LanguageRuntime/ObjC/ObjCLanguageRuntime.cpp
index 87ae4c2c6c48..9eb493f83c84 100644
--- a/lldb/source/Plugins/LanguageRuntime/ObjC/ObjCLanguageRuntime.cpp
+++ b/lldb/source/Plugins/LanguageRuntime/ObjC/ObjCLanguageRuntime.cpp
@@ -222,14 +222,6 @@ ObjCLanguageRuntime::GetParentClass(ObjCLanguageRuntime::ObjCISA isa) {
   return 0;
 }
 
-ConstString
-ObjCLanguageRuntime::GetActualTypeName(ObjCLanguageRuntime::ObjCISA isa) {
-  ClassDescriptorSP objc_class_sp(GetNonKVOClassDescriptor(isa));
-  if (objc_class_sp)
-    return objc_class_sp->GetClassName();
-  return ConstString();
-}
-
 ObjCLanguageRuntime::ClassDescriptorSP
 ObjCLanguageRuntime::GetClassDescriptorFromClassName(
     ConstString class_name) {
@@ -313,14 +305,6 @@ ObjCLanguageRuntime::EncodingToType::RealizeType(const char *name,
   return CompilerType();
 }
 
-CompilerType ObjCLanguageRuntime::EncodingToType::RealizeType(
-    ClangASTContext &ast_ctx, const char *name, bool for_expression) {
-  clang::ASTContext *clang_ast = ast_ctx.getASTContext();
-  if (!clang_ast)
-    return CompilerType();
-  return RealizeType(*clang_ast, name, for_expression);
-}
-
 ObjCLanguageRuntime::EncodingToType::~EncodingToType() {}
 
 ObjCLanguageRuntime::EncodingToTypeSP ObjCLanguageRuntime::GetEncodingToType() {
diff --git a/lldb/source/Plugins/LanguageRuntime/ObjC/ObjCLanguageRuntime.h b/lldb/source/Plugins/LanguageRuntime/ObjC/ObjCLanguageRuntime.h
index 39acd6e9f268..b9a4d5dae08a 100644
--- a/lldb/source/Plugins/LanguageRuntime/ObjC/ObjCLanguageRuntime.h
+++ b/lldb/source/Plugins/LanguageRuntime/ObjC/ObjCLanguageRuntime.h
@@ -145,12 +145,9 @@ public:
     virtual ~EncodingToType();
 
     virtual CompilerType RealizeType(ClangASTContext &ast_ctx, const char *name,
-                                     bool for_expression);
+                                     bool for_expression) = 0;
     virtual CompilerType RealizeType(const char *name, bool for_expression);
 
-    virtual CompilerType RealizeType(clang::ASTContext &ast_ctx,
-                                     const char *name, bool for_expression) = 0;
-
   protected:
     std::unique_ptr<ClangASTContext> m_scratch_ast_ctx_up;
   };
@@ -274,8 +271,6 @@ public:
 
   virtual ObjCISA GetISA(ConstString name);
 
-  virtual ConstString GetActualTypeName(ObjCISA isa);
-
   virtual ObjCISA GetParentClass(ObjCISA isa);
 
   // Finds the byte offset of the child_type ivar in parent_type.  If it can't
diff --git a/lldb/source/Plugins/LanguageRuntime/RenderScript/RenderScriptRuntime/RenderScriptRuntime.cpp b/lldb/source/Plugins/LanguageRuntime/RenderScript/RenderScriptRuntime/RenderScriptRuntime.cpp
index 5200749d759f..4edb8dec6082 100644
--- a/lldb/source/Plugins/LanguageRuntime/RenderScript/RenderScriptRuntime/RenderScriptRuntime.cpp
+++ b/lldb/source/Plugins/LanguageRuntime/RenderScript/RenderScriptRuntime/RenderScriptRuntime.cpp
@@ -2240,8 +2240,7 @@ void RenderScriptRuntime::FindStructTypeName(Element &elem,
   // Iterate over all the global variables looking for one with a matching type
   // to the Element. We make the assumption a match exists since there needs to
   // be a global variable to reflect the struct type back into java host code.
-  for (uint32_t i = 0; i < var_list.GetSize(); ++i) {
-    const VariableSP var_sp(var_list.GetVariableAtIndex(i));
+  for (const VariableSP &var_sp : var_list) {
     if (!var_sp)
       continue;
 
@@ -3892,7 +3891,7 @@ void RSModuleDescriptor::Dump(Stream &strm) const {
   int indent = strm.GetIndentLevel();
 
   strm.Indent();
-  m_module->GetFileSpec().Dump(&strm);
+  m_module->GetFileSpec().Dump(strm.AsRawOstream());
   strm.Indent(m_module->GetNumCompileUnits() ? "Debug info loaded."
                                              : "Debug info does not exist.");
   strm.EOL();
diff --git a/lldb/source/Plugins/LanguageRuntime/RenderScript/RenderScriptRuntime/RenderScriptx86ABIFixups.cpp b/lldb/source/Plugins/LanguageRuntime/RenderScript/RenderScriptRuntime/RenderScriptx86ABIFixups.cpp
index a6d225d2fbd8..4ddff3ad9c4c 100644
--- a/lldb/source/Plugins/LanguageRuntime/RenderScript/RenderScriptRuntime/RenderScriptx86ABIFixups.cpp
+++ b/lldb/source/Plugins/LanguageRuntime/RenderScript/RenderScriptRuntime/RenderScriptx86ABIFixups.cpp
@@ -72,7 +72,7 @@ bool isRSAllocationTyCallSite(llvm::Module &module, llvm::CallInst *call_inst) {
   (void)module;
   if (!call_inst->hasByValArgument())
     return false;
-  for (const auto &param : call_inst->operand_values())
+  for (const auto *param : call_inst->operand_values())
     if (isRSAllocationPtrTy(param->getType()))
       return true;
   return false;
diff --git a/lldb/source/Plugins/ObjectFile/Breakpad/BreakpadRecords.cpp b/lldb/source/Plugins/ObjectFile/Breakpad/BreakpadRecords.cpp
index de17d986a860..b83b2efb492f 100644
--- a/lldb/source/Plugins/ObjectFile/Breakpad/BreakpadRecords.cpp
+++ b/lldb/source/Plugins/ObjectFile/Breakpad/BreakpadRecords.cpp
@@ -72,7 +72,7 @@ llvm::Triple::ArchType stringTo<llvm::Triple::ArchType>(llvm::StringRef Str) {
       .Case("sparc", Triple::sparc)
       .Case("sparcv9", Triple::sparcv9)
       .Case("x86", Triple::x86)
-      .Case("x86_64", Triple::x86_64)
+      .Cases("x86_64", "x86_64h", Triple::x86_64)
       .Default(Triple::UnknownArch);
 }
 
diff --git a/lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp b/lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
index 3f8502548fc2..8b62afa18cd6 100644
--- a/lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
+++ b/lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
@@ -1572,8 +1572,10 @@ static SectionType GetSectionTypeFromName(llvm::StringRef Name) {
         .Case("info.dwo", eSectionTypeDWARFDebugInfoDwo)
         .Cases("line", "line.dwo", eSectionTypeDWARFDebugLine)
         .Cases("line_str", "line_str.dwo", eSectionTypeDWARFDebugLineStr)
-        .Cases("loc", "loc.dwo", eSectionTypeDWARFDebugLoc)
-        .Cases("loclists", "loclists.dwo", eSectionTypeDWARFDebugLocLists)
+        .Case("loc", eSectionTypeDWARFDebugLoc)
+        .Case("loc.dwo", eSectionTypeDWARFDebugLocDwo)
+        .Case("loclists", eSectionTypeDWARFDebugLocLists)
+        .Case("loclists.dwo", eSectionTypeDWARFDebugLocListsDwo)
         .Case("macinfo", eSectionTypeDWARFDebugMacInfo)
         .Cases("macro", "macro.dwo", eSectionTypeDWARFDebugMacro)
         .Case("names", eSectionTypeDWARFDebugNames)
@@ -1581,6 +1583,7 @@ static SectionType GetSectionTypeFromName(llvm::StringRef Name) {
         .Case("pubtypes", eSectionTypeDWARFDebugPubTypes)
         .Case("ranges", eSectionTypeDWARFDebugRanges)
         .Case("rnglists", eSectionTypeDWARFDebugRngLists)
+        .Case("rnglists.dwo", eSectionTypeDWARFDebugRngListsDwo)
         .Case("str", eSectionTypeDWARFDebugStr)
         .Case("str.dwo", eSectionTypeDWARFDebugStrDwo)
         .Case("str_offsets", eSectionTypeDWARFDebugStrOffsets)
@@ -2257,6 +2260,8 @@ unsigned ObjectFileELF::ParseSymbols(Symtab *symtab, user_id_t start_id,
         symbol_size_valid,              // Symbol size is valid
         has_suffix,                     // Contains linker annotations?
         flags);                         // Symbol flags.
+    if (symbol.getBinding() == STB_WEAK)
+      dc_symbol.SetIsWeak(true);
     symtab->AddSymbol(dc_symbol);
   }
   return i;
diff --git a/lldb/source/Plugins/OperatingSystem/Python/OperatingSystemPython.cpp b/lldb/source/Plugins/OperatingSystem/Python/OperatingSystemPython.cpp
index b777a5319104..b04ac61c99a1 100644
--- a/lldb/source/Plugins/OperatingSystem/Python/OperatingSystemPython.cpp
+++ b/lldb/source/Plugins/OperatingSystem/Python/OperatingSystemPython.cpp
@@ -6,7 +6,9 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef LLDB_DISABLE_PYTHON
+#include "lldb/Host/Config.h"
+
+#if LLDB_ENABLE_PYTHON
 
 #include "OperatingSystemPython.h"
 
@@ -88,13 +90,12 @@ OperatingSystemPython::OperatingSystemPython(lldb_private::Process *process,
         python_module_path.GetFilename().AsCString(""));
     if (!os_plugin_class_name.empty()) {
       const bool init_session = false;
-      const bool allow_reload = true;
       char python_module_path_cstr[PATH_MAX];
       python_module_path.GetPath(python_module_path_cstr,
                                  sizeof(python_module_path_cstr));
       Status error;
-      if (m_interpreter->LoadScriptingModule(
-              python_module_path_cstr, allow_reload, init_session, error)) {
+      if (m_interpreter->LoadScriptingModule(python_module_path_cstr,
+                                             init_session, error)) {
         // Strip the ".py" extension if there is one
         size_t py_extension_pos = os_plugin_class_name.rfind(".py");
         if (py_extension_pos != std::string::npos)
@@ -166,7 +167,7 @@ bool OperatingSystemPython::UpdateThreadList(ThreadList &old_thread_list,
   Target &target = m_process->GetTarget();
   std::unique_lock<std::recursive_mutex> api_lock(target.GetAPIMutex(),
                                                   std::defer_lock);
-  api_lock.try_lock();
+  (void)api_lock.try_lock(); // See above.
   auto interpreter_lock = m_interpreter->AcquireInterpreterLock();
 
   LLDB_LOGF(log,
@@ -308,7 +309,7 @@ OperatingSystemPython::CreateRegisterContextForThread(Thread *thread,
   Target &target = m_process->GetTarget();
   std::unique_lock<std::recursive_mutex> api_lock(target.GetAPIMutex(),
                                                   std::defer_lock);
-  api_lock.try_lock();
+  (void)api_lock.try_lock(); // See above.
   auto interpreter_lock = m_interpreter->AcquireInterpreterLock();
 
   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_THREAD));
@@ -395,7 +396,7 @@ lldb::ThreadSP OperatingSystemPython::CreateThread(lldb::tid_t tid,
     Target &target = m_process->GetTarget();
     std::unique_lock<std::recursive_mutex> api_lock(target.GetAPIMutex(),
                                                     std::defer_lock);
-    api_lock.try_lock();
+    (void)api_lock.try_lock(); // See above.
     auto interpreter_lock = m_interpreter->AcquireInterpreterLock();
 
     StructuredData::DictionarySP thread_info_dict =
@@ -416,4 +417,4 @@ lldb::ThreadSP OperatingSystemPython::CreateThread(lldb::tid_t tid,
   return ThreadSP();
 }
 
-#endif // #ifndef LLDB_DISABLE_PYTHON
+#endif // #if LLDB_ENABLE_PYTHON
diff --git a/lldb/source/Plugins/OperatingSystem/Python/OperatingSystemPython.h b/lldb/source/Plugins/OperatingSystem/Python/OperatingSystemPython.h
index e76227ddb981..4a594cf29a08 100644
--- a/lldb/source/Plugins/OperatingSystem/Python/OperatingSystemPython.h
+++ b/lldb/source/Plugins/OperatingSystem/Python/OperatingSystemPython.h
@@ -9,7 +9,9 @@
 #ifndef liblldb_OperatingSystemPython_h_
 #define liblldb_OperatingSystemPython_h_
 
-#ifndef LLDB_DISABLE_PYTHON
+#include "lldb/Host/Config.h"
+
+#if LLDB_ENABLE_PYTHON
 
 #include "lldb/Target/OperatingSystem.h"
 #include "lldb/Utility/StructuredData.h"
@@ -80,6 +82,6 @@ protected:
   lldb_private::StructuredData::ObjectSP m_python_object_sp;
 };
 
-#endif // LLDB_DISABLE_PYTHON
+#endif
 
 #endif // liblldb_OperatingSystemPython_h_
diff --git a/lldb/source/Plugins/Platform/FreeBSD/PlatformFreeBSD.cpp b/lldb/source/Plugins/Platform/FreeBSD/PlatformFreeBSD.cpp
index 946f0ea3a5cf..261f44c230f9 100644
--- a/lldb/source/Plugins/Platform/FreeBSD/PlatformFreeBSD.cpp
+++ b/lldb/source/Plugins/Platform/FreeBSD/PlatformFreeBSD.cpp
@@ -10,7 +10,7 @@
 #include "lldb/Host/Config.h"
 
 #include <stdio.h>
-#ifndef LLDB_DISABLE_POSIX
+#if LLDB_ENABLE_POSIX
 #include <sys/utsname.h>
 #endif
 
@@ -194,7 +194,7 @@ bool PlatformFreeBSD::GetSupportedArchitectureAtIndex(uint32_t idx,
 void PlatformFreeBSD::GetStatus(Stream &strm) {
   Platform::GetStatus(strm);
 
-#ifndef LLDB_DISABLE_POSIX
+#if LLDB_ENABLE_POSIX
   // Display local kernel information only when we are running in host mode.
   // Otherwise, we would end up printing non-FreeBSD information (when running
   // on Mac OS for example).
diff --git a/lldb/source/Plugins/Platform/NetBSD/PlatformNetBSD.cpp b/lldb/source/Plugins/Platform/NetBSD/PlatformNetBSD.cpp
index 63245d18fc5c..53f819e6a272 100644
--- a/lldb/source/Plugins/Platform/NetBSD/PlatformNetBSD.cpp
+++ b/lldb/source/Plugins/Platform/NetBSD/PlatformNetBSD.cpp
@@ -10,7 +10,7 @@
 #include "lldb/Host/Config.h"
 
 #include <stdio.h>
-#ifndef LLDB_DISABLE_POSIX
+#if LLDB_ENABLE_POSIX
 #include <sys/utsname.h>
 #endif
 
@@ -168,7 +168,7 @@ bool PlatformNetBSD::GetSupportedArchitectureAtIndex(uint32_t idx,
 void PlatformNetBSD::GetStatus(Stream &strm) {
   Platform::GetStatus(strm);
 
-#ifndef LLDB_DISABLE_POSIX
+#if LLDB_ENABLE_POSIX
   // Display local kernel information only when we are running in host mode.
   // Otherwise, we would end up printing non-NetBSD information (when running
   // on Mac OS for example).
diff --git a/lldb/source/Plugins/Platform/OpenBSD/PlatformOpenBSD.cpp b/lldb/source/Plugins/Platform/OpenBSD/PlatformOpenBSD.cpp
index 9dfb8844c574..1b63e2da0a4f 100644
--- a/lldb/source/Plugins/Platform/OpenBSD/PlatformOpenBSD.cpp
+++ b/lldb/source/Plugins/Platform/OpenBSD/PlatformOpenBSD.cpp
@@ -10,7 +10,7 @@
 #include "lldb/Host/Config.h"
 
 #include <stdio.h>
-#ifndef LLDB_DISABLE_POSIX
+#if LLDB_ENABLE_POSIX
 #include <sys/utsname.h>
 #endif
 
@@ -173,7 +173,7 @@ bool PlatformOpenBSD::GetSupportedArchitectureAtIndex(uint32_t idx,
 void PlatformOpenBSD::GetStatus(Stream &strm) {
   Platform::GetStatus(strm);
 
-#ifndef LLDB_DISABLE_POSIX
+#if LLDB_ENABLE_POSIX
   // Display local kernel information only when we are running in host mode.
   // Otherwise, we would end up printing non-OpenBSD information (when running
   // on Mac OS for example).
diff --git a/lldb/source/Plugins/Platform/POSIX/PlatformPOSIX.cpp b/lldb/source/Plugins/Platform/POSIX/PlatformPOSIX.cpp
index b12e21deb459..2b64be63a623 100644
--- a/lldb/source/Plugins/Platform/POSIX/PlatformPOSIX.cpp
+++ b/lldb/source/Plugins/Platform/POSIX/PlatformPOSIX.cpp
@@ -223,7 +223,7 @@ static uint32_t chown_file(Platform *platform, const char *path,
     command.Printf(":%d", gid);
   command.Printf("%s", path);
   int status;
-  platform->RunShellCommand(command.GetData(), nullptr, &status, nullptr,
+  platform->RunShellCommand(command.GetData(), FileSpec(), &status, nullptr,
                             nullptr, std::chrono::seconds(10));
   return status;
 }
@@ -235,7 +235,7 @@ PlatformPOSIX::PutFile(const lldb_private::FileSpec &source,
   Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_PLATFORM));
 
   if (IsHost()) {
-    if (FileSpec::Equal(source, destination, true))
+    if (source == destination)
       return Status();
     // cp src dst
     // chown uid:gid dst
@@ -248,7 +248,7 @@ PlatformPOSIX::PutFile(const lldb_private::FileSpec &source,
     StreamString command;
     command.Printf("cp %s %s", src_path.c_str(), dst_path.c_str());
     int status;
-    RunShellCommand(command.GetData(), nullptr, &status, nullptr, nullptr,
+    RunShellCommand(command.GetData(), FileSpec(), &status, nullptr, nullptr,
                     std::chrono::seconds(10));
     if (status != 0)
       return Status("unable to perform copy");
@@ -278,7 +278,7 @@ PlatformPOSIX::PutFile(const lldb_private::FileSpec &source,
                        GetHostname(), dst_path.c_str());
       LLDB_LOGF(log, "[PutFile] Running command: %s\n", command.GetData());
       int retcode;
-      Host::RunShellCommand(command.GetData(), nullptr, &retcode, nullptr,
+      Host::RunShellCommand(command.GetData(), FileSpec(), &retcode, nullptr,
                             nullptr, std::chrono::minutes(1));
       if (retcode == 0) {
         // Don't chown a local file for a remote system
@@ -307,14 +307,14 @@ lldb_private::Status PlatformPOSIX::GetFile(
   if (dst_path.empty())
     return Status("unable to get file path for destination");
   if (IsHost()) {
-    if (FileSpec::Equal(source, destination, true))
+    if (source == destination)
       return Status("local scenario->source and destination are the same file "
                     "path: no operation performed");
     // cp src dst
     StreamString cp_command;
     cp_command.Printf("cp %s %s", src_path.c_str(), dst_path.c_str());
     int status;
-    RunShellCommand(cp_command.GetData(), nullptr, &status, nullptr, nullptr,
+    RunShellCommand(cp_command.GetData(), FileSpec(), &status, nullptr, nullptr,
                     std::chrono::seconds(10));
     if (status != 0)
       return Status("unable to perform copy");
@@ -335,7 +335,7 @@ lldb_private::Status PlatformPOSIX::GetFile(
                        dst_path.c_str());
       LLDB_LOGF(log, "[GetFile] Running command: %s\n", command.GetData());
       int retcode;
-      Host::RunShellCommand(command.GetData(), nullptr, &retcode, nullptr,
+      Host::RunShellCommand(command.GetData(), FileSpec(), &retcode, nullptr,
                             nullptr, std::chrono::minutes(1));
       if (retcode == 0)
         return Status();
@@ -706,7 +706,9 @@ PlatformPOSIX::MakeLoadImageUtilityFunction(ExecutionContext &exe_ctx,
   FunctionCaller *do_dlopen_function = nullptr;
 
   // Fetch the clang types we will need:
-  ClangASTContext *ast = process->GetTarget().GetScratchClangASTContext();
+  ClangASTContext *ast = ClangASTContext::GetScratch(process->GetTarget());
+  if (!ast)
+    return nullptr;
 
   CompilerType clang_void_pointer_type
       = ast->GetBasicType(eBasicTypeVoid).GetPointerType();
@@ -948,7 +950,11 @@ uint32_t PlatformPOSIX::DoLoadImage(lldb_private::Process *process,
 
   Value return_value;
   // Fetch the clang types we will need:
-  ClangASTContext *ast = process->GetTarget().GetScratchClangASTContext();
+  ClangASTContext *ast = ClangASTContext::GetScratch(process->GetTarget());
+  if (!ast) {
+    error.SetErrorString("dlopen error: Unable to get ClangASTContext");
+    return LLDB_INVALID_IMAGE_TOKEN;
+  }
 
   CompilerType clang_void_pointer_type
       = ast->GetBasicType(eBasicTypeVoid).GetPointerType();
diff --git a/lldb/source/Plugins/Process/NetBSD/NativeProcessNetBSD.cpp b/lldb/source/Plugins/Process/NetBSD/NativeProcessNetBSD.cpp
index 8b6f9fbc33c3..4313d27e11e9 100644
--- a/lldb/source/Plugins/Process/NetBSD/NativeProcessNetBSD.cpp
+++ b/lldb/source/Plugins/Process/NetBSD/NativeProcessNetBSD.cpp
@@ -8,8 +8,7 @@
 
 #include "NativeProcessNetBSD.h"
 
-
-
+#include "Plugins/Process/NetBSD/NativeRegisterContextNetBSD.h"
 #include "Plugins/Process/POSIX/ProcessPOSIXLog.h"
 #include "lldb/Host/HostProcess.h"
 #include "lldb/Host/common/NativeRegisterContext.h"
@@ -99,6 +98,17 @@ NativeProcessNetBSD::Factory::Launch(ProcessLaunchInfo &launch_info,
       pid, launch_info.GetPTY().ReleaseMasterFileDescriptor(), native_delegate,
       Info.GetArchitecture(), mainloop));
 
+  // Enable event reporting
+  ptrace_event_t events;
+  status = PtraceWrapper(PT_GET_EVENT_MASK, pid, &events, sizeof(events));
+  if (status.Fail())
+    return status.ToError();
+  // TODO: PTRACE_FORK | PTRACE_VFORK | PTRACE_POSIX_SPAWN?
+  events.pe_set_event |= PTRACE_LWP_CREATE | PTRACE_LWP_EXIT;
+  status = PtraceWrapper(PT_SET_EVENT_MASK, pid, &events, sizeof(events));
+  if (status.Fail())
+    return status.ToError();
+
   status = process_up->ReinitializeThreads();
   if (status.Fail())
     return status.ToError();
@@ -211,17 +221,32 @@ void NativeProcessNetBSD::MonitorSIGTRAP(lldb::pid_t pid) {
     return;
   }
 
+  NativeThreadNetBSD* thread = nullptr;
+  if (info.psi_lwpid > 0) {
+    for (const auto &t : m_threads) {
+      if (t->GetID() == static_cast<lldb::tid_t>(info.psi_lwpid)) {
+        thread = static_cast<NativeThreadNetBSD *>(t.get());
+        break;
+      }
+      static_cast<NativeThreadNetBSD *>(t.get())->SetStoppedWithNoReason();
+    }
+    if (!thread)
+      LLDB_LOG(log,
+               "thread not found in m_threads, pid = {0}, LWP = {1}", pid,
+               info.psi_lwpid);
+  }
+
   switch (info.psi_siginfo.si_code) {
   case TRAP_BRKPT:
-    for (const auto &thread : m_threads) {
-      static_cast<NativeThreadNetBSD &>(*thread).SetStoppedByBreakpoint();
-      FixupBreakpointPCAsNeeded(static_cast<NativeThreadNetBSD &>(*thread));
+    if (thread) {
+      thread->SetStoppedByBreakpoint();
+      FixupBreakpointPCAsNeeded(*thread);
     }
     SetState(StateType::eStateStopped, true);
     break;
   case TRAP_TRACE:
-    for (const auto &thread : m_threads)
-      static_cast<NativeThreadNetBSD &>(*thread).SetStoppedByTrace();
+    if (thread)
+      thread->SetStoppedByTrace();
     SetState(StateType::eStateStopped, true);
     break;
   case TRAP_EXEC: {
@@ -238,54 +263,66 @@ void NativeProcessNetBSD::MonitorSIGTRAP(lldb::pid_t pid) {
       static_cast<NativeThreadNetBSD &>(*thread).SetStoppedByExec();
     SetState(StateType::eStateStopped, true);
   } break;
-  case TRAP_DBREG: {
-    // Find the thread.
-    NativeThreadNetBSD* thread = nullptr;
-    for (const auto &t : m_threads) {
-      if (t->GetID() == info.psi_lwpid) {
-        thread = static_cast<NativeThreadNetBSD *>(t.get());
+  case TRAP_LWP: {
+    ptrace_state_t pst;
+    Status error = PtraceWrapper(PT_GET_PROCESS_STATE, pid, &pst, sizeof(pst));
+    if (error.Fail()) {
+      SetState(StateType::eStateInvalid);
+      return;
+    }
+
+    switch (pst.pe_report_event) {
+      case PTRACE_LWP_CREATE: {
+        LLDB_LOG(log,
+                 "monitoring new thread, pid = {0}, LWP = {1}", pid,
+                 pst.pe_lwp);
+        NativeThreadNetBSD& t = AddThread(pst.pe_lwp);
+        error = t.CopyWatchpointsFrom(
+            static_cast<NativeThreadNetBSD &>(*GetCurrentThread()));
+        if (error.Fail()) {
+          LLDB_LOG(log,
+                   "failed to copy watchpoints to new thread {0}: {1}",
+                   pst.pe_lwp, error);
+          SetState(StateType::eStateInvalid);
+          return;
+        }
+      } break;
+      case PTRACE_LWP_EXIT:
+        LLDB_LOG(log,
+                 "removing exited thread, pid = {0}, LWP = {1}", pid,
+                 pst.pe_lwp);
+        RemoveThread(pst.pe_lwp);
         break;
-      }
     }
-    if (!thread) {
-      LLDB_LOG(log,
-               "thread not found in m_threads, pid = {0}, LWP = {1}",
-               GetID(), info.psi_lwpid);
-      break;
+
+    error = PtraceWrapper(PT_CONTINUE, pid, reinterpret_cast<void*>(1), 0);
+    if (error.Fail()) {
+      SetState(StateType::eStateInvalid);
+      return;
     }
+  } break;
+  case TRAP_DBREG: {
+    if (!thread)
+      break;
 
-    // If a watchpoint was hit, report it
+    auto &regctx = static_cast<NativeRegisterContextNetBSD &>(
+        thread->GetRegisterContext());
     uint32_t wp_index = LLDB_INVALID_INDEX32;
-    Status error = thread->GetRegisterContext().GetWatchpointHitIndex(
-        wp_index, (uintptr_t)info.psi_siginfo.si_addr);
+    Status error = regctx.GetWatchpointHitIndex(wp_index,
+        (uintptr_t)info.psi_siginfo.si_addr);
     if (error.Fail())
       LLDB_LOG(log,
                "received error while checking for watchpoint hits, pid = "
-               "{0}, LWP = {1}, error = {2}",
-               GetID(), info.psi_lwpid, error);
+               "{0}, LWP = {1}, error = {2}", pid, info.psi_lwpid, error);
     if (wp_index != LLDB_INVALID_INDEX32) {
-      for (const auto &thread : m_threads)
-        static_cast<NativeThreadNetBSD &>(*thread).SetStoppedByWatchpoint(
-            wp_index);
+      thread->SetStoppedByWatchpoint(wp_index);
+      regctx.ClearWatchpointHit(wp_index);
       SetState(StateType::eStateStopped, true);
       break;
     }
 
-    // If a breakpoint was hit, report it
-    uint32_t bp_index = LLDB_INVALID_INDEX32;
-    error = thread->GetRegisterContext().GetHardwareBreakHitIndex(
-        bp_index, (uintptr_t)info.psi_siginfo.si_addr);
-    if (error.Fail())
-      LLDB_LOG(log,
-               "received error while checking for hardware "
-               "breakpoint hits, pid = {0}, LWP = {1}, error = {2}",
-               GetID(), info.psi_lwpid, error);
-    if (bp_index != LLDB_INVALID_INDEX32) {
-      for (const auto &thread : m_threads)
-        static_cast<NativeThreadNetBSD &>(*thread).SetStoppedByBreakpoint();
-      SetState(StateType::eStateStopped, true);
-      break;
-    }
+    thread->SetStoppedByTrace();
+    SetState(StateType::eStateStopped, true);
   } break;
   }
 }
@@ -295,9 +332,14 @@ void NativeProcessNetBSD::MonitorSignal(lldb::pid_t pid, int signal) {
   const auto siginfo_err =
       PtraceWrapper(PT_GET_SIGINFO, pid, &info, sizeof(info));
 
-  for (const auto &thread : m_threads) {
-    static_cast<NativeThreadNetBSD &>(*thread).SetStoppedBySignal(
-        info.psi_siginfo.si_signo, &info.psi_siginfo);
+  for (const auto &abs_thread : m_threads) {
+    NativeThreadNetBSD &thread = static_cast<NativeThreadNetBSD &>(*abs_thread);
+    assert(info.psi_lwpid >= 0);
+    if (info.psi_lwpid == 0 ||
+        static_cast<lldb::tid_t>(info.psi_lwpid) == thread.GetID())
+      thread.SetStoppedBySignal(info.psi_siginfo.si_signo, &info.psi_siginfo);
+    else
+      thread.SetStoppedWithNoReason();
   }
   SetState(StateType::eStateStopped, true);
 }
@@ -325,68 +367,137 @@ Status NativeProcessNetBSD::PtraceWrapper(int req, lldb::pid_t pid, void *addr,
   return error;
 }
 
+static llvm::Expected<ptrace_siginfo_t> ComputeSignalInfo(
+    const std::vector<std::unique_ptr<NativeThreadProtocol>> &threads,
+    const ResumeActionList &resume_actions) {
+  // We need to account for three possible scenarios:
+  // 1. no signal being sent.
+  // 2. a signal being sent to one thread.
+  // 3. a signal being sent to the whole process.
+
+  // Count signaled threads.  While at it, determine which signal is being sent
+  // and ensure there's only one.
+  size_t signaled_threads = 0;
+  int signal = LLDB_INVALID_SIGNAL_NUMBER;
+  lldb::tid_t signaled_lwp;
+  for (const auto &thread : threads) {
+    assert(thread && "thread list should not contain NULL threads");
+    const ResumeAction *action =
+        resume_actions.GetActionForThread(thread->GetID(), true);
+    if (action) {
+      if (action->signal != LLDB_INVALID_SIGNAL_NUMBER) {
+        signaled_threads++;
+        if (action->signal != signal) {
+          if (signal != LLDB_INVALID_SIGNAL_NUMBER)
+            return Status("NetBSD does not support passing multiple signals "
+                          "simultaneously")
+                .ToError();
+          signal = action->signal;
+          signaled_lwp = thread->GetID();
+        }
+      }
+    }
+  }
+
+  if (signaled_threads == 0) {
+    ptrace_siginfo_t siginfo;
+    siginfo.psi_siginfo.si_signo = LLDB_INVALID_SIGNAL_NUMBER;
+    return siginfo;
+  }
+
+  if (signaled_threads > 1 && signaled_threads < threads.size())
+    return Status("NetBSD does not support passing signal to 1<i<all threads")
+        .ToError();
+
+  ptrace_siginfo_t siginfo;
+  siginfo.psi_siginfo.si_signo = signal;
+  siginfo.psi_siginfo.si_code = SI_USER;
+  siginfo.psi_siginfo.si_pid = getpid();
+  siginfo.psi_siginfo.si_uid = getuid();
+  if (signaled_threads == 1)
+    siginfo.psi_lwpid = signaled_lwp;
+  else // signal for the whole process
+    siginfo.psi_lwpid = 0;
+  return siginfo;
+}
+
 Status NativeProcessNetBSD::Resume(const ResumeActionList &resume_actions) {
   Log *log(ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_PROCESS));
   LLDB_LOG(log, "pid {0}", GetID());
 
-  const auto &thread = m_threads[0];
-  const ResumeAction *const action =
-      resume_actions.GetActionForThread(thread->GetID(), true);
+  Status ret;
 
-  if (action == nullptr) {
-    LLDB_LOG(log, "no action specified for pid {0} tid {1}", GetID(),
-             thread->GetID());
-    return Status();
-  }
+  Expected<ptrace_siginfo_t> siginfo =
+      ComputeSignalInfo(m_threads, resume_actions);
+  if (!siginfo)
+    return Status(siginfo.takeError());
 
-  Status error;
-  int signal =
-      action->signal != LLDB_INVALID_SIGNAL_NUMBER ? action->signal : 0;
-
-  switch (action->state) {
-  case eStateRunning: {
-    // Run the thread, possibly feeding it the signal.
-    error = NativeProcessNetBSD::PtraceWrapper(PT_CONTINUE, GetID(), (void *)1,
-                                               signal);
-    if (!error.Success())
-      return error;
-    for (const auto &thread : m_threads)
-      static_cast<NativeThreadNetBSD &>(*thread).SetRunning();
-    SetState(eStateRunning, true);
-    break;
-  }
-  case eStateStepping:
-    // Run the thread, possibly feeding it the signal.
-    error = NativeProcessNetBSD::PtraceWrapper(PT_STEP, GetID(), (void *)1,
-                                               signal);
-    if (!error.Success())
-      return error;
-    for (const auto &thread : m_threads)
-      static_cast<NativeThreadNetBSD &>(*thread).SetStepping();
-    SetState(eStateStepping, true);
-    break;
+  for (const auto &abs_thread : m_threads) {
+    assert(abs_thread && "thread list should not contain NULL threads");
+    NativeThreadNetBSD &thread = static_cast<NativeThreadNetBSD &>(*abs_thread);
 
-  case eStateSuspended:
-  case eStateStopped:
-    llvm_unreachable("Unexpected state");
+    const ResumeAction *action =
+        resume_actions.GetActionForThread(thread.GetID(), true);
+    // we need to explicit issue suspend requests, so it is simpler to map it
+    // into proper action
+    ResumeAction suspend_action{thread.GetID(), eStateSuspended,
+                                LLDB_INVALID_SIGNAL_NUMBER};
 
-  default:
-    return Status("NativeProcessNetBSD::%s (): unexpected state %s specified "
-                  "for pid %" PRIu64 ", tid %" PRIu64,
-                  __FUNCTION__, StateAsCString(action->state), GetID(),
-                  thread->GetID());
+    if (action == nullptr) {
+      LLDB_LOG(log, "no action specified for pid {0} tid {1}", GetID(),
+               thread.GetID());
+      action = &suspend_action;
+    }
+
+    LLDB_LOG(
+        log,
+        "processing resume action state {0} signal {1} for pid {2} tid {3}",
+        action->state, action->signal, GetID(), thread.GetID());
+
+    switch (action->state) {
+    case eStateRunning:
+      ret = thread.Resume();
+      break;
+    case eStateStepping:
+      ret = thread.SingleStep();
+      break;
+    case eStateSuspended:
+    case eStateStopped:
+      if (action->signal != LLDB_INVALID_SIGNAL_NUMBER)
+        return Status("Passing signal to suspended thread unsupported");
+
+      ret = thread.Suspend();
+      break;
+
+    default:
+      return Status("NativeProcessNetBSD::%s (): unexpected state %s specified "
+                    "for pid %" PRIu64 ", tid %" PRIu64,
+                    __FUNCTION__, StateAsCString(action->state), GetID(),
+                    thread.GetID());
+    }
+
+    if (!ret.Success())
+      return ret;
   }
 
-  return Status();
+  int signal = 0;
+  if (siginfo->psi_siginfo.si_signo != LLDB_INVALID_SIGNAL_NUMBER) {
+    ret = PtraceWrapper(PT_SET_SIGINFO, GetID(), &siginfo.get(),
+                        sizeof(*siginfo));
+    if (!ret.Success())
+      return ret;
+    signal = siginfo->psi_siginfo.si_signo;
+  }
+
+  ret = PtraceWrapper(PT_CONTINUE, GetID(), reinterpret_cast<void *>(1),
+                      signal);
+  if (ret.Success())
+    SetState(eStateRunning, true);
+  return ret;
 }
 
 Status NativeProcessNetBSD::Halt() {
-  Status error;
-
-  if (kill(GetID(), SIGSTOP) != 0)
-    error.SetErrorToErrno();
-
-  return error;
+  return PtraceWrapper(PT_STOP, GetID());
 }
 
 Status NativeProcessNetBSD::Detach() {
@@ -411,6 +522,10 @@ Status NativeProcessNetBSD::Signal(int signo) {
   return error;
 }
 
+Status NativeProcessNetBSD::Interrupt() {
+  return PtraceWrapper(PT_STOP, GetID());
+}
+
 Status NativeProcessNetBSD::Kill() {
   Log *log(ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_PROCESS));
   LLDB_LOG(log, "pid {0}", GetID());
@@ -650,10 +765,10 @@ bool NativeProcessNetBSD::HasThreadNoLock(lldb::tid_t thread_id) {
 }
 
 NativeThreadNetBSD &NativeProcessNetBSD::AddThread(lldb::tid_t thread_id) {
-
   Log *log(ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_THREAD));
   LLDB_LOG(log, "pid {0} adding thread with tid {1}", GetID(), thread_id);
 
+  assert(thread_id > 0);
   assert(!HasThreadNoLock(thread_id) &&
          "attempted to add a thread by id that already exists");
 
@@ -665,6 +780,22 @@ NativeThreadNetBSD &NativeProcessNetBSD::AddThread(lldb::tid_t thread_id) {
   return static_cast<NativeThreadNetBSD &>(*m_threads.back());
 }
 
+void NativeProcessNetBSD::RemoveThread(lldb::tid_t thread_id) {
+  Log *log(ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_THREAD));
+  LLDB_LOG(log, "pid {0} removing thread with tid {1}", GetID(), thread_id);
+
+  assert(thread_id > 0);
+  assert(HasThreadNoLock(thread_id) &&
+         "attempted to remove a thread that does not exist");
+
+  for (auto it = m_threads.begin(); it != m_threads.end(); ++it) {
+    if ((*it)->GetID() == thread_id) {
+      m_threads.erase(it);
+      break;
+    }
+  }
+}
+
 Status NativeProcessNetBSD::Attach() {
   // Attach to the requested process.
   // An attach will cause the thread to stop with a SIGSTOP.
@@ -783,15 +914,23 @@ Status NativeProcessNetBSD::ReinitializeThreads() {
   m_threads.clear();
 
   // Initialize new thread
+#ifdef PT_LWPSTATUS
+  struct ptrace_lwpstatus info = {};
+  int op = PT_LWPNEXT;
+#else
   struct ptrace_lwpinfo info = {};
-  Status error = PtraceWrapper(PT_LWPINFO, GetID(), &info, sizeof(info));
+  int op = PT_LWPINFO;
+#endif
+
+  Status error = PtraceWrapper(op, GetID(), &info, sizeof(info));
+
   if (error.Fail()) {
     return error;
   }
   // Reinitialize from scratch threads and register them in process
   while (info.pl_lwpid != 0) {
     AddThread(info.pl_lwpid);
-    error = PtraceWrapper(PT_LWPINFO, GetID(), &info, sizeof(info));
+    error = PtraceWrapper(op, GetID(), &info, sizeof(info));
     if (error.Fail()) {
       return error;
     }
diff --git a/lldb/source/Plugins/Process/NetBSD/NativeProcessNetBSD.h b/lldb/source/Plugins/Process/NetBSD/NativeProcessNetBSD.h
index 4e7f0a1c13ab..6a06773f40a8 100644
--- a/lldb/source/Plugins/Process/NetBSD/NativeProcessNetBSD.h
+++ b/lldb/source/Plugins/Process/NetBSD/NativeProcessNetBSD.h
@@ -47,6 +47,8 @@ public:
 
   Status Signal(int signo) override;
 
+  Status Interrupt() override;
+
   Status Kill() override;
 
   Status GetMemoryRegionInfo(lldb::addr_t load_addr,
@@ -98,6 +100,7 @@ private:
   bool HasThreadNoLock(lldb::tid_t thread_id);
 
   NativeThreadNetBSD &AddThread(lldb::tid_t thread_id);
+  void RemoveThread(lldb::tid_t thread_id);
 
   void MonitorCallback(lldb::pid_t pid, int signal);
   void MonitorExited(lldb::pid_t pid, WaitStatus status);
diff --git a/lldb/source/Plugins/Process/NetBSD/NativeRegisterContextNetBSD.cpp b/lldb/source/Plugins/Process/NetBSD/NativeRegisterContextNetBSD.cpp
index 3a9caaad74c8..a8afa0b20305 100644
--- a/lldb/source/Plugins/Process/NetBSD/NativeRegisterContextNetBSD.cpp
+++ b/lldb/source/Plugins/Process/NetBSD/NativeRegisterContextNetBSD.cpp
@@ -8,6 +8,8 @@
 
 #include "NativeRegisterContextNetBSD.h"
 
+#include "Plugins/Process/NetBSD/NativeProcessNetBSD.h"
+
 #include "lldb/Host/common/NativeProcessProtocol.h"
 
 using namespace lldb_private;
diff --git a/lldb/source/Plugins/Process/NetBSD/NativeRegisterContextNetBSD.h b/lldb/source/Plugins/Process/NetBSD/NativeRegisterContextNetBSD.h
index f5dd0c33b677..13e023d856d2 100644
--- a/lldb/source/Plugins/Process/NetBSD/NativeRegisterContextNetBSD.h
+++ b/lldb/source/Plugins/Process/NetBSD/NativeRegisterContextNetBSD.h
@@ -11,12 +11,13 @@
 
 #include "lldb/Host/common/NativeThreadProtocol.h"
 
-#include "Plugins/Process/NetBSD/NativeProcessNetBSD.h"
 #include "Plugins/Process/Utility/NativeRegisterContextRegisterInfo.h"
 
 namespace lldb_private {
 namespace process_netbsd {
 
+class NativeProcessNetBSD;
+
 class NativeRegisterContextNetBSD : public NativeRegisterContextRegisterInfo {
 public:
   NativeRegisterContextNetBSD(NativeThreadProtocol &native_thread,
@@ -30,6 +31,10 @@ public:
   static NativeRegisterContextNetBSD *
   CreateHostNativeRegisterContextNetBSD(const ArchSpec &target_arch,
                                         NativeThreadProtocol &native_thread);
+  virtual Status
+  CopyHardwareWatchpointsFrom(NativeRegisterContextNetBSD &source) = 0;
+
+  virtual Status ClearWatchpointHit(uint32_t wp_index) = 0;
 
 protected:
   Status DoRegisterSet(int req, void *buf);
diff --git a/lldb/source/Plugins/Process/NetBSD/NativeRegisterContextNetBSD_x86_64.cpp b/lldb/source/Plugins/Process/NetBSD/NativeRegisterContextNetBSD_x86_64.cpp
index 6cc2810fa235..05a35401da46 100644
--- a/lldb/source/Plugins/Process/NetBSD/NativeRegisterContextNetBSD_x86_64.cpp
+++ b/lldb/source/Plugins/Process/NetBSD/NativeRegisterContextNetBSD_x86_64.cpp
@@ -84,13 +84,71 @@ static_assert((sizeof(g_gpr_regnums_x86_64) / sizeof(g_gpr_regnums_x86_64[0])) -
                   k_num_gpr_registers_x86_64,
               "g_gpr_regnums_x86_64 has wrong number of register infos");
 
+// x86 64-bit floating point registers.
+static const uint32_t g_fpu_regnums_x86_64[] = {
+    lldb_fctrl_x86_64,     lldb_fstat_x86_64, lldb_ftag_x86_64,
+    lldb_fop_x86_64,       lldb_fiseg_x86_64, lldb_fioff_x86_64,
+    lldb_foseg_x86_64,     lldb_fooff_x86_64, lldb_mxcsr_x86_64,
+    lldb_mxcsrmask_x86_64, lldb_st0_x86_64,   lldb_st1_x86_64,
+    lldb_st2_x86_64,       lldb_st3_x86_64,   lldb_st4_x86_64,
+    lldb_st5_x86_64,       lldb_st6_x86_64,   lldb_st7_x86_64,
+    lldb_mm0_x86_64,       lldb_mm1_x86_64,   lldb_mm2_x86_64,
+    lldb_mm3_x86_64,       lldb_mm4_x86_64,   lldb_mm5_x86_64,
+    lldb_mm6_x86_64,       lldb_mm7_x86_64,   lldb_xmm0_x86_64,
+    lldb_xmm1_x86_64,      lldb_xmm2_x86_64,  lldb_xmm3_x86_64,
+    lldb_xmm4_x86_64,      lldb_xmm5_x86_64,  lldb_xmm6_x86_64,
+    lldb_xmm7_x86_64,      lldb_xmm8_x86_64,  lldb_xmm9_x86_64,
+    lldb_xmm10_x86_64,     lldb_xmm11_x86_64, lldb_xmm12_x86_64,
+    lldb_xmm13_x86_64,     lldb_xmm14_x86_64, lldb_xmm15_x86_64,
+    LLDB_INVALID_REGNUM // register sets need to end with this flag
+};
+static_assert((sizeof(g_fpu_regnums_x86_64) / sizeof(g_fpu_regnums_x86_64[0])) -
+                      1 ==
+                  k_num_fpr_registers_x86_64,
+              "g_fpu_regnums_x86_64 has wrong number of register infos");
+
+// x86 64-bit registers available via XState.
+static const uint32_t g_xstate_regnums_x86_64[] = {
+    lldb_ymm0_x86_64,   lldb_ymm1_x86_64,  lldb_ymm2_x86_64,  lldb_ymm3_x86_64,
+    lldb_ymm4_x86_64,   lldb_ymm5_x86_64,  lldb_ymm6_x86_64,  lldb_ymm7_x86_64,
+    lldb_ymm8_x86_64,   lldb_ymm9_x86_64,  lldb_ymm10_x86_64, lldb_ymm11_x86_64,
+    lldb_ymm12_x86_64,  lldb_ymm13_x86_64, lldb_ymm14_x86_64, lldb_ymm15_x86_64,
+    // Note: we currently do not provide them but this is needed to avoid
+    // unnamed groups in SBFrame::GetRegisterContext().
+    lldb_bnd0_x86_64,    lldb_bnd1_x86_64,    lldb_bnd2_x86_64,
+    lldb_bnd3_x86_64,    lldb_bndcfgu_x86_64, lldb_bndstatus_x86_64,
+    LLDB_INVALID_REGNUM // register sets need to end with this flag
+};
+static_assert((sizeof(g_xstate_regnums_x86_64) / sizeof(g_xstate_regnums_x86_64[0])) -
+                      1 ==
+                  k_num_avx_registers_x86_64 + k_num_mpx_registers_x86_64,
+              "g_xstate_regnums_x86_64 has wrong number of register infos");
+
+// x86 debug registers.
+static const uint32_t g_dbr_regnums_x86_64[] = {
+    lldb_dr0_x86_64,   lldb_dr1_x86_64,  lldb_dr2_x86_64,  lldb_dr3_x86_64,
+    lldb_dr4_x86_64,   lldb_dr5_x86_64,  lldb_dr6_x86_64,  lldb_dr7_x86_64,
+    LLDB_INVALID_REGNUM // register sets need to end with this flag
+};
+static_assert((sizeof(g_dbr_regnums_x86_64) / sizeof(g_dbr_regnums_x86_64[0])) -
+                      1 ==
+                  k_num_dbr_registers_x86_64,
+              "g_dbr_regnums_x86_64 has wrong number of register infos");
+
 // Number of register sets provided by this context.
-enum { k_num_extended_register_sets = 2, k_num_register_sets = 4 };
+enum { k_num_register_sets = 4 };
 
 // Register sets for x86 64-bit.
 static const RegisterSet g_reg_sets_x86_64[k_num_register_sets] = {
     {"General Purpose Registers", "gpr", k_num_gpr_registers_x86_64,
      g_gpr_regnums_x86_64},
+    {"Floating Point Registers", "fpu", k_num_fpr_registers_x86_64,
+     g_fpu_regnums_x86_64},
+    {"Extended State Registers", "xstate",
+     k_num_avx_registers_x86_64 + k_num_mpx_registers_x86_64,
+     g_xstate_regnums_x86_64},
+    {"Debug Registers", "dbr", k_num_dbr_registers_x86_64,
+     g_dbr_regnums_x86_64},
 };
 
 #define REG_CONTEXT_SIZE (GetRegisterInfoInterface().GetGPRSize())
@@ -667,11 +725,6 @@ Status NativeRegisterContextNetBSD_x86_64::ReadAllRegisterValues(
   ::memcpy(dst, &m_gpr_x86_64, GetRegisterInfoInterface().GetGPRSize());
   dst += GetRegisterInfoInterface().GetGPRSize();
 
-  RegisterValue value((uint64_t)-1);
-  const RegisterInfo *reg_info =
-      GetRegisterInfoInterface().GetDynamicRegisterInfo("orig_eax");
-  if (reg_info == nullptr)
-    reg_info = GetRegisterInfoInterface().GetDynamicRegisterInfo("orig_rax");
   return error;
 }
 
@@ -795,10 +848,10 @@ Status NativeRegisterContextNetBSD_x86_64::SetHardwareWatchpointWithIndex(
   if (!is_vacant)
     return Status("Watchpoint index not vacant");
 
-  RegisterValue reg_value;
   const RegisterInfo *const reg_info_dr7 =
       GetRegisterInfoAtIndex(lldb_dr7_x86_64);
-  error = ReadRegister(reg_info_dr7, reg_value);
+  RegisterValue dr7_value;
+  error = ReadRegister(reg_info_dr7, dr7_value);
   if (error.Fail())
     return error;
 
@@ -816,16 +869,28 @@ Status NativeRegisterContextNetBSD_x86_64::SetHardwareWatchpointWithIndex(
 
   uint64_t bit_mask = (0x3 << (2 * wp_index)) | (0xF << (16 + 4 * wp_index));
 
-  uint64_t control_bits = reg_value.GetAsUInt64() & ~bit_mask;
+  uint64_t control_bits = dr7_value.GetAsUInt64() & ~bit_mask;
 
   control_bits |= enable_bit | rw_bits | size_bits;
 
   const RegisterInfo *const reg_info_drN =
       GetRegisterInfoAtIndex(lldb_dr0_x86_64 + wp_index);
-  error = WriteRegister(reg_info_drN, RegisterValue(addr));
+  RegisterValue drN_value;
+  error = ReadRegister(reg_info_drN, drN_value);
   if (error.Fail())
     return error;
 
+  // clear dr6 if address or bits changed (i.e. we're not reenabling the same
+  // watchpoint)
+  if (drN_value.GetAsUInt64() != addr ||
+      (dr7_value.GetAsUInt64() & bit_mask) != (rw_bits | size_bits)) {
+    ClearWatchpointHit(wp_index);
+
+    error = WriteRegister(reg_info_drN, RegisterValue(addr));
+    if (error.Fail())
+      return error;
+  }
+
   error = WriteRegister(reg_info_dr7, RegisterValue(control_bits));
   if (error.Fail())
     return error;
@@ -839,32 +904,36 @@ bool NativeRegisterContextNetBSD_x86_64::ClearHardwareWatchpoint(
   if (wp_index >= NumSupportedHardwareWatchpoints())
     return false;
 
+  // for watchpoints 0, 1, 2, or 3, respectively, clear bits 0-1, 2-3, 4-5
+  // or 6-7 of the debug control register (DR7)
+  const RegisterInfo *const reg_info_dr7 =
+      GetRegisterInfoAtIndex(lldb_dr7_x86_64);
   RegisterValue reg_value;
+  Status error = ReadRegister(reg_info_dr7, reg_value);
+  if (error.Fail())
+    return false;
+  uint64_t bit_mask = 0x3 << (2 * wp_index);
+  uint64_t control_bits = reg_value.GetAsUInt64() & ~bit_mask;
 
-  // for watchpoints 0, 1, 2, or 3, respectively, clear bits 0, 1, 2, or 3 of
+  return WriteRegister(reg_info_dr7, RegisterValue(control_bits)).Success();
+}
+
+Status NativeRegisterContextNetBSD_x86_64::ClearWatchpointHit(uint32_t wp_index) {
+  if (wp_index >= NumSupportedHardwareWatchpoints())
+    return Status("Watchpoint index out of range");
+
+  // for watchpoints 0, 1, 2, or 3, respectively, check bits 0, 1, 2, or 3 of
   // the debug status register (DR6)
   const RegisterInfo *const reg_info_dr6 =
       GetRegisterInfoAtIndex(lldb_dr6_x86_64);
+  RegisterValue reg_value;
   Status error = ReadRegister(reg_info_dr6, reg_value);
   if (error.Fail())
-    return false;
+    return error;
+
   uint64_t bit_mask = 1 << wp_index;
   uint64_t status_bits = reg_value.GetAsUInt64() & ~bit_mask;
-  error = WriteRegister(reg_info_dr6, RegisterValue(status_bits));
-  if (error.Fail())
-    return false;
-
-  // for watchpoints 0, 1, 2, or 3, respectively, clear bits {0-1,16-19},
-  // {2-3,20-23}, {4-5,24-27}, or {6-7,28-31} of the debug control register
-  // (DR7)
-  const RegisterInfo *const reg_info_dr7 =
-      GetRegisterInfoAtIndex(lldb_dr7_x86_64);
-  error = ReadRegister(reg_info_dr7, reg_value);
-  if (error.Fail())
-    return false;
-  bit_mask = (0x3 << (2 * wp_index)) | (0xF << (16 + 4 * wp_index));
-  uint64_t control_bits = reg_value.GetAsUInt64() & ~bit_mask;
-  return WriteRegister(reg_info_dr7, RegisterValue(control_bits)).Success();
+  return WriteRegister(reg_info_dr6, RegisterValue(status_bits));
 }
 
 Status NativeRegisterContextNetBSD_x86_64::ClearAllHardwareWatchpoints() {
@@ -930,4 +999,19 @@ uint32_t NativeRegisterContextNetBSD_x86_64::NumSupportedHardwareWatchpoints() {
   return 4;
 }
 
+Status NativeRegisterContextNetBSD_x86_64::CopyHardwareWatchpointsFrom(
+    NativeRegisterContextNetBSD &source) {
+  auto &r_source = static_cast<NativeRegisterContextNetBSD_x86_64&>(source);
+  Status res = r_source.ReadRegisterSet(DBRegSet);
+  if (!res.Fail()) {
+    // copy dbregs only if any watchpoints were set
+    if ((r_source.m_dbr_x86_64.dr[7] & 0xFF) == 0)
+      return res;
+
+    m_dbr_x86_64 = r_source.m_dbr_x86_64;
+    res = WriteRegisterSet(DBRegSet);
+  }
+  return res;
+}
+
 #endif // defined(__x86_64__)
diff --git a/lldb/source/Plugins/Process/NetBSD/NativeRegisterContextNetBSD_x86_64.h b/lldb/source/Plugins/Process/NetBSD/NativeRegisterContextNetBSD_x86_64.h
index 0fed16542a95..54b8a806267f 100644
--- a/lldb/source/Plugins/Process/NetBSD/NativeRegisterContextNetBSD_x86_64.h
+++ b/lldb/source/Plugins/Process/NetBSD/NativeRegisterContextNetBSD_x86_64.h
@@ -58,6 +58,8 @@ public:
 
   bool ClearHardwareWatchpoint(uint32_t wp_index) override;
 
+  Status ClearWatchpointHit(uint32_t wp_index) override;
+
   Status ClearAllHardwareWatchpoints() override;
 
   Status SetHardwareWatchpointWithIndex(lldb::addr_t addr, size_t size,
@@ -71,9 +73,12 @@ public:
 
   uint32_t NumSupportedHardwareWatchpoints() override;
 
+  Status
+  CopyHardwareWatchpointsFrom(NativeRegisterContextNetBSD &source) override;
+
 private:
   // Private member types.
-  enum { GPRegSet, FPRegSet, DBRegSet, XStateRegSet };
+  enum { GPRegSet, FPRegSet, XStateRegSet, DBRegSet };
 
   // Private member variables.
   struct reg m_gpr_x86_64;
diff --git a/lldb/source/Plugins/Process/NetBSD/NativeThreadNetBSD.cpp b/lldb/source/Plugins/Process/NetBSD/NativeThreadNetBSD.cpp
index e25975c93446..dd2745d9330e 100644
--- a/lldb/source/Plugins/Process/NetBSD/NativeThreadNetBSD.cpp
+++ b/lldb/source/Plugins/Process/NetBSD/NativeThreadNetBSD.cpp
@@ -16,9 +16,20 @@
 #include "lldb/Utility/LLDBAssert.h"
 #include "lldb/Utility/RegisterValue.h"
 #include "lldb/Utility/State.h"
+#include "llvm/Support/Errno.h"
+
+// clang-format off
+#include <sys/types.h>
+#include <sys/ptrace.h>
+// clang-format on
 
 #include <sstream>
 
+// clang-format off
+#include <sys/types.h>
+#include <sys/sysctl.h>
+// clang-format on
+
 using namespace lldb;
 using namespace lldb_private;
 using namespace lldb_private::process_netbsd;
@@ -30,6 +41,38 @@ NativeThreadNetBSD::NativeThreadNetBSD(NativeProcessNetBSD &process,
 NativeRegisterContextNetBSD::CreateHostNativeRegisterContextNetBSD(process.GetArchitecture(), *this)
 ), m_stop_description() {}
 
+Status NativeThreadNetBSD::Resume() {
+  Status ret = NativeProcessNetBSD::PtraceWrapper(PT_RESUME, m_process.GetID(),
+                                                  nullptr, GetID());
+  if (!ret.Success())
+    return ret;
+  ret = NativeProcessNetBSD::PtraceWrapper(PT_CLEARSTEP, m_process.GetID(),
+                                           nullptr, GetID());
+  if (ret.Success())
+    SetRunning();
+  return ret;
+}
+
+Status NativeThreadNetBSD::SingleStep() {
+  Status ret = NativeProcessNetBSD::PtraceWrapper(PT_RESUME, m_process.GetID(),
+                                                  nullptr, GetID());
+  if (!ret.Success())
+    return ret;
+  ret = NativeProcessNetBSD::PtraceWrapper(PT_SETSTEP, m_process.GetID(),
+                                           nullptr, GetID());
+  if (ret.Success())
+    SetStepping();
+  return ret;
+}
+
+Status NativeThreadNetBSD::Suspend() {
+  Status ret = NativeProcessNetBSD::PtraceWrapper(PT_SUSPEND, m_process.GetID(),
+                                                  nullptr, GetID());
+  if (ret.Success())
+    SetStopped();
+  return ret;
+}
+
 void NativeThreadNetBSD::SetStoppedBySignal(uint32_t signo,
                                             const siginfo_t *info) {
   Log *log(ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_THREAD));
@@ -89,6 +132,13 @@ void NativeThreadNetBSD::SetStoppedByWatchpoint(uint32_t wp_index) {
   m_stop_info.details.signal.signo = SIGTRAP;
 }
 
+void NativeThreadNetBSD::SetStoppedWithNoReason() {
+  SetStopped();
+
+  m_stop_info.reason = StopReason::eStopReasonNone;
+  m_stop_info.details.signal.signo = 0;
+}
+
 void NativeThreadNetBSD::SetStopped() {
   const StateType new_state = StateType::eStateStopped;
   m_state = new_state;
@@ -105,7 +155,49 @@ void NativeThreadNetBSD::SetStepping() {
   m_stop_info.reason = StopReason::eStopReasonNone;
 }
 
-std::string NativeThreadNetBSD::GetName() { return std::string(""); }
+std::string NativeThreadNetBSD::GetName() {
+  Log *log(ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_THREAD));
+
+#ifdef PT_LWPSTATUS
+  struct ptrace_lwpstatus info = {};
+  info.pl_lwpid = m_tid;
+  Status error = NativeProcessNetBSD::PtraceWrapper(
+      PT_LWPSTATUS, static_cast<int>(m_process.GetID()), &info, sizeof(info));
+  if (error.Fail()) {
+    return "";
+  }
+  return info.pl_name;
+#else
+  std::vector<struct kinfo_lwp> infos;
+  int mib[5] = {CTL_KERN, KERN_LWP, static_cast<int>(m_process.GetID()),
+                sizeof(struct kinfo_lwp), 0};
+  size_t size;
+
+  if (::sysctl(mib, 5, nullptr, &size, nullptr, 0) == -1 || size == 0) {
+    LLDB_LOG(log, "sysctl() for LWP info size failed: {0}",
+             llvm::sys::StrError());
+    return "";
+  }
+
+  mib[4] = size / sizeof(size_t);
+  infos.resize(size / sizeof(struct kinfo_lwp));
+
+  if (sysctl(mib, 5, infos.data(), &size, NULL, 0) == -1 || size == 0) {
+    LLDB_LOG(log, "sysctl() for LWP info failed: {0}", llvm::sys::StrError());
+    return "";
+  }
+
+  size_t nlwps = size / sizeof(struct kinfo_lwp);
+  for (size_t i = 0; i < nlwps; i++) {
+    if (static_cast<lldb::tid_t>(infos[i].l_lid) == m_tid) {
+      return infos[i].l_name;
+    }
+  }
+
+  LLDB_LOG(log, "unable to find lwp {0} in LWP infos", m_tid);
+  return "";
+#endif
+}
 
 lldb::StateType NativeThreadNetBSD::GetState() { return m_state; }
 
@@ -140,9 +232,9 @@ bool NativeThreadNetBSD::GetStopReason(ThreadStopInfo &stop_info,
   llvm_unreachable("unhandled StateType!");
 }
 
-NativeRegisterContext& NativeThreadNetBSD::GetRegisterContext() {
+NativeRegisterContextNetBSD &NativeThreadNetBSD::GetRegisterContext() {
   assert(m_reg_context_up);
-return  *m_reg_context_up;
+  return *m_reg_context_up;
 }
 
 Status NativeThreadNetBSD::SetWatchpoint(lldb::addr_t addr, size_t size,
@@ -203,3 +295,13 @@ Status NativeThreadNetBSD::RemoveHardwareBreakpoint(lldb::addr_t addr) {
 
   return Status("Clearing hardware breakpoint failed.");
 }
+
+Status NativeThreadNetBSD::CopyWatchpointsFrom(NativeThreadNetBSD &source) {
+  Status s = GetRegisterContext().CopyHardwareWatchpointsFrom(
+      source.GetRegisterContext());
+  if (!s.Fail()) {
+    m_watchpoint_index_map = source.m_watchpoint_index_map;
+    m_hw_break_index_map = source.m_hw_break_index_map;
+  }
+  return s;
+}
diff --git a/lldb/source/Plugins/Process/NetBSD/NativeThreadNetBSD.h b/lldb/source/Plugins/Process/NetBSD/NativeThreadNetBSD.h
index 015d8995db34..89b61ef86722 100644
--- a/lldb/source/Plugins/Process/NetBSD/NativeThreadNetBSD.h
+++ b/lldb/source/Plugins/Process/NetBSD/NativeThreadNetBSD.h
@@ -11,6 +11,8 @@
 
 #include "lldb/Host/common/NativeThreadProtocol.h"
 
+#include "Plugins/Process/NetBSD/NativeRegisterContextNetBSD.h"
+
 #include <csignal>
 #include <map>
 #include <string>
@@ -34,7 +36,7 @@ public:
   bool GetStopReason(ThreadStopInfo &stop_info,
                      std::string &description) override;
 
-  NativeRegisterContext& GetRegisterContext() override;
+  NativeRegisterContextNetBSD &GetRegisterContext() override;
 
   Status SetWatchpoint(lldb::addr_t addr, size_t size, uint32_t watch_flags,
                        bool hardware) override;
@@ -48,19 +50,26 @@ public:
 private:
   // Interface for friend classes
 
+  Status Resume();
+  Status SingleStep();
+  Status Suspend();
+
   void SetStoppedBySignal(uint32_t signo, const siginfo_t *info = nullptr);
   void SetStoppedByBreakpoint();
   void SetStoppedByTrace();
   void SetStoppedByExec();
   void SetStoppedByWatchpoint(uint32_t wp_index);
+  void SetStoppedWithNoReason();
   void SetStopped();
   void SetRunning();
   void SetStepping();
 
+  Status CopyWatchpointsFrom(NativeThreadNetBSD& source);
+
   // Member Variables
   lldb::StateType m_state;
   ThreadStopInfo m_stop_info;
-  std::unique_ptr<NativeRegisterContext> m_reg_context_up;
+  std::unique_ptr<NativeRegisterContextNetBSD> m_reg_context_up;
   std::string m_stop_description;
   using WatchpointIndexMap = std::map<lldb::addr_t, uint32_t>;
   WatchpointIndexMap m_watchpoint_index_map;
diff --git a/lldb/source/Plugins/Process/POSIX/CrashReason.cpp b/lldb/source/Plugins/Process/POSIX/CrashReason.cpp
index 9678e48436e7..b872269fdfe1 100644
--- a/lldb/source/Plugins/Process/POSIX/CrashReason.cpp
+++ b/lldb/source/Plugins/Process/POSIX/CrashReason.cpp
@@ -136,15 +136,15 @@ std::string GetCrashReasonString(CrashReason reason, const siginfo_t &info) {
 #if defined(si_lower) && defined(si_upper)
   if (reason == CrashReason::eBoundViolation) {
     str = "signal SIGSEGV";
-    AppendBounds(str, reinterpret_cast<lldb::addr_t>(info.si_lower),
-                 reinterpret_cast<lldb::addr_t>(info.si_upper),
-                 reinterpret_cast<lldb::addr_t>(info.si_addr));
+    AppendBounds(str, reinterpret_cast<uintptr_t>(info.si_lower),
+                 reinterpret_cast<uintptr_t>(info.si_upper),
+                 reinterpret_cast<uintptr_t>(info.si_addr));
     return str;
   }
 #endif
 
   return GetCrashReasonString(reason,
-                              reinterpret_cast<lldb::addr_t>(info.si_addr));
+                              reinterpret_cast<uintptr_t>(info.si_addr));
 }
 
 std::string GetCrashReasonString(CrashReason reason, lldb::addr_t fault_addr) {
diff --git a/lldb/source/Plugins/Process/Utility/InferiorCallPOSIX.cpp b/lldb/source/Plugins/Process/Utility/InferiorCallPOSIX.cpp
index 2ccbeacc4960..ee939b01d350 100644
--- a/lldb/source/Plugins/Process/Utility/InferiorCallPOSIX.cpp
+++ b/lldb/source/Plugins/Process/Utility/InferiorCallPOSIX.cpp
@@ -20,7 +20,7 @@
 #include "lldb/Target/Target.h"
 #include "lldb/Target/ThreadPlanCallFunction.h"
 
-#ifndef LLDB_DISABLE_POSIX
+#if LLDB_ENABLE_POSIX
 #include <sys/mman.h>
 #else
 // define them
diff --git a/lldb/source/Plugins/Process/Utility/RegisterContextDarwin_arm.cpp b/lldb/source/Plugins/Process/Utility/RegisterContextDarwin_arm.cpp
index 4ca33c248c6f..173e66904151 100644
--- a/lldb/source/Plugins/Process/Utility/RegisterContextDarwin_arm.cpp
+++ b/lldb/source/Plugins/Process/Utility/RegisterContextDarwin_arm.cpp
@@ -21,12 +21,6 @@
 
 #include <memory>
 
-// Support building against older versions of LLVM, this macro was added
-// recently.
-#ifndef LLVM_EXTENSION
-#define LLVM_EXTENSION
-#endif
-
 #include "Utility/ARM_DWARF_Registers.h"
 #include "Utility/ARM_ehframe_Registers.h"
 
@@ -1146,10 +1140,11 @@ bool RegisterContextDarwin_arm::ReadRegister(const RegisterInfo *reg_info,
   case gpr_sp:
   case gpr_lr:
   case gpr_pc:
-  case gpr_cpsr:
     value.SetUInt32(gpr.r[reg - gpr_r0]);
     break;
-
+  case gpr_cpsr:
+    value.SetUInt32(gpr.cpsr);
+    break;
   case fpu_s0:
   case fpu_s1:
   case fpu_s2:
diff --git a/lldb/source/Plugins/Process/Utility/RegisterContextDarwin_arm64.cpp b/lldb/source/Plugins/Process/Utility/RegisterContextDarwin_arm64.cpp
index b3ec24d8905d..fa5197cd6bf4 100644
--- a/lldb/source/Plugins/Process/Utility/RegisterContextDarwin_arm64.cpp
+++ b/lldb/source/Plugins/Process/Utility/RegisterContextDarwin_arm64.cpp
@@ -30,12 +30,6 @@
 #include <sys/sysctl.h>
 #endif
 
-// Support building against older versions of LLVM, this macro was added
-// recently.
-#ifndef LLVM_EXTENSION
-#define LLVM_EXTENSION
-#endif
-
 #include "Utility/ARM64_DWARF_Registers.h"
 
 using namespace lldb;
diff --git a/lldb/source/Plugins/Process/Utility/RegisterContextDarwin_i386.cpp b/lldb/source/Plugins/Process/Utility/RegisterContextDarwin_i386.cpp
index 873713fd8373..959b04700b17 100644
--- a/lldb/source/Plugins/Process/Utility/RegisterContextDarwin_i386.cpp
+++ b/lldb/source/Plugins/Process/Utility/RegisterContextDarwin_i386.cpp
@@ -19,12 +19,6 @@
 
 #include <memory>
 
-// Support building against older versions of LLVM, this macro was added
-// recently.
-#ifndef LLVM_EXTENSION
-#define LLVM_EXTENSION
-#endif
-
 #include "RegisterContextDarwin_i386.h"
 
 using namespace lldb;
diff --git a/lldb/source/Plugins/Process/Utility/RegisterContextDarwin_x86_64.cpp b/lldb/source/Plugins/Process/Utility/RegisterContextDarwin_x86_64.cpp
index 47758ce85eb2..22088a7d6448 100644
--- a/lldb/source/Plugins/Process/Utility/RegisterContextDarwin_x86_64.cpp
+++ b/lldb/source/Plugins/Process/Utility/RegisterContextDarwin_x86_64.cpp
@@ -21,12 +21,6 @@
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/Support/Compiler.h"
 
-// Support building against older versions of LLVM, this macro was added
-// recently.
-#ifndef LLVM_EXTENSION
-#define LLVM_EXTENSION
-#endif
-
 #include "RegisterContextDarwin_x86_64.h"
 
 using namespace lldb;
diff --git a/lldb/source/Plugins/Process/Utility/RegisterInfos_x86_64.h b/lldb/source/Plugins/Process/Utility/RegisterInfos_x86_64.h
index 4a3b3c73fd6b..af3027afa73c 100644
--- a/lldb/source/Plugins/Process/Utility/RegisterInfos_x86_64.h
+++ b/lldb/source/Plugins/Process/Utility/RegisterInfos_x86_64.h
@@ -25,15 +25,18 @@
    LLVM_EXTENSION offsetof(FPR, xsave) +                                       \
    LLVM_EXTENSION offsetof(XSAVE, ymmh[0]) + (32 * reg_index))
 
+// Guarantees BNDR/BNDC offsets do not overlap with YMM offsets.
+#define GDB_REMOTE_OFFSET 128
+
 #define BNDR_OFFSET(reg_index)                                                 \
   (LLVM_EXTENSION offsetof(UserArea, fpr) +                                    \
    LLVM_EXTENSION offsetof(FPR, xsave) +                                       \
-   LLVM_EXTENSION offsetof(XSAVE, mpxr[reg_index]))
+   LLVM_EXTENSION offsetof(XSAVE, mpxr[reg_index]) + GDB_REMOTE_OFFSET)
 
 #define BNDC_OFFSET(reg_index)                                                 \
   (LLVM_EXTENSION offsetof(UserArea, fpr) +                                    \
    LLVM_EXTENSION offsetof(FPR, xsave) +                                       \
-   LLVM_EXTENSION offsetof(XSAVE, mpxc[reg_index]))
+   LLVM_EXTENSION offsetof(XSAVE, mpxc[reg_index]) + GDB_REMOTE_OFFSET)
 
 #ifdef DECLARE_REGISTER_INFOS_X86_64_STRUCT
 
diff --git a/lldb/source/Plugins/Process/Utility/lldb-x86-register-enums.h b/lldb/source/Plugins/Process/Utility/lldb-x86-register-enums.h
index 0d2149c83573..bfdd586d9ded 100644
--- a/lldb/source/Plugins/Process/Utility/lldb-x86-register-enums.h
+++ b/lldb/source/Plugins/Process/Utility/lldb-x86-register-enums.h
@@ -294,7 +294,8 @@ enum {
   lldb_bndstatus_x86_64,
   k_last_mpxc_x86_64 = lldb_bndstatus_x86_64,
 
-  lldb_dr0_x86_64,
+  k_first_dbr_x86_64,
+  lldb_dr0_x86_64 = k_first_dbr_x86_64,
   lldb_dr1_x86_64,
   lldb_dr2_x86_64,
   lldb_dr3_x86_64,
@@ -302,6 +303,7 @@ enum {
   lldb_dr5_x86_64,
   lldb_dr6_x86_64,
   lldb_dr7_x86_64,
+  k_last_dbr_x86_64 = lldb_dr7_x86_64,
 
   k_num_registers_x86_64,
   k_num_gpr_registers_x86_64 = k_last_gpr_x86_64 - k_first_gpr_x86_64 + 1,
@@ -312,6 +314,7 @@ enum {
                                 k_num_fpr_registers_x86_64 +
                                 k_num_avx_registers_x86_64 +
                                 k_num_mpx_registers_x86_64,
+  k_num_dbr_registers_x86_64 = k_last_dbr_x86_64 - k_first_dbr_x86_64 + 1,
 };
 }
 
diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp
index 144ae103faa4..7cea013eea7f 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp
@@ -31,6 +31,7 @@
 #include "lldb/Utility/FileSpec.h"
 #include "lldb/Utility/Log.h"
 #include "lldb/Utility/RegularExpression.h"
+#include "lldb/Utility/Reproducer.h"
 #include "lldb/Utility/StreamString.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/Support/ScopedPrinter.h"
@@ -49,7 +50,7 @@
 #include <compression.h>
 #endif
 
-#if defined(HAVE_LIBZ)
+#if LLVM_ENABLE_ZLIB
 #include <zlib.h>
 #endif
 
@@ -581,7 +582,7 @@ bool GDBRemoteCommunication::DecompressPacket() {
   }
 #endif
 
-#if defined(HAVE_LIBZ)
+#if LLVM_ENABLE_ZLIB
   if (decompressed_bytes == 0 && decompressed_bufsize != ULONG_MAX &&
       decompressed_buffer != nullptr &&
       m_compression_type == CompressionType::ZlibDeflate) {
@@ -1243,8 +1244,9 @@ Status GDBRemoteCommunication::StartDebugserverProcess(
 
 void GDBRemoteCommunication::DumpHistory(Stream &strm) { m_history.Dump(strm); }
 
-void GDBRemoteCommunication::SetHistoryStream(llvm::raw_ostream *strm) {
-  m_history.SetStream(strm);
+void GDBRemoteCommunication::SetPacketRecorder(
+    repro::PacketRecorder *recorder) {
+  m_history.SetRecorder(recorder);
 }
 
 llvm::Error
diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.h b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.h
index bb777a5c26a7..0b670018bd69 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.h
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.h
@@ -27,6 +27,9 @@
 #include "lldb/lldb-public.h"
 
 namespace lldb_private {
+namespace repro {
+class PacketRecorder;
+}
 namespace process_gdb_remote {
 
 enum GDBStoppointType {
@@ -133,7 +136,8 @@ public:
                          // fork/exec to avoid having to connect/accept
 
   void DumpHistory(Stream &strm);
-  void SetHistoryStream(llvm::raw_ostream *strm);
+
+  void SetPacketRecorder(repro::PacketRecorder *recorder);
 
   static llvm::Error ConnectLocally(GDBRemoteCommunication &client,
                                     GDBRemoteCommunication &server);
diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
index feb9f0589cee..b2f1ee527e8b 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
@@ -543,21 +543,24 @@ GDBRemoteCommunicationClient::SendThreadSpecificPacketAndWaitForResponse(
 //
 // Takes a valid thread ID because p needs to apply to a thread.
 bool GDBRemoteCommunicationClient::GetpPacketSupported(lldb::tid_t tid) {
-  if (m_supports_p == eLazyBoolCalculate) {
-    m_supports_p = eLazyBoolNo;
-    StreamString payload;
-    payload.PutCString("p0");
-    StringExtractorGDBRemote response;
-    if (SendThreadSpecificPacketAndWaitForResponse(tid, std::move(payload),
-                                                   response, false) ==
-            PacketResult::Success &&
-        response.IsNormalResponse()) {
-      m_supports_p = eLazyBoolYes;
-    }
-  }
+  if (m_supports_p == eLazyBoolCalculate)
+    m_supports_p = GetThreadPacketSupported(tid, "p0");
   return m_supports_p;
 }
 
+LazyBool GDBRemoteCommunicationClient::GetThreadPacketSupported(
+    lldb::tid_t tid, llvm::StringRef packetStr) {
+  StreamString payload;
+  payload.PutCString(packetStr);
+  StringExtractorGDBRemote response;
+  if (SendThreadSpecificPacketAndWaitForResponse(
+          tid, std::move(payload), response, false) == PacketResult::Success &&
+      response.IsNormalResponse()) {
+    return eLazyBoolYes;
+  }
+  return eLazyBoolNo;
+}
+
 StructuredData::ObjectSP GDBRemoteCommunicationClient::GetThreadsInfo() {
   // Get information on all threads at one using the "jThreadsInfo" packet
   StructuredData::ObjectSP object_sp;
@@ -1042,7 +1045,7 @@ void GDBRemoteCommunicationClient::MaybeEnableCompression(
   }
 #endif
 
-#if defined(HAVE_LIBZ)
+#if LLVM_ENABLE_ZLIB
   if (avail_type == CompressionType::None) {
     for (auto compression : supported_compressions) {
       if (compression == "zlib-deflate") {
@@ -3737,7 +3740,7 @@ bool GDBRemoteCommunicationClient::ReadExtFeature(
     case ('m'):
       if (str.length() > 1)
         output << &str[1];
-      offset += size;
+      offset += str.length() - 1;
       break;
 
     // unknown chunk
diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.h b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.h
index 574cd0fd70c5..11fd40bce44f 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.h
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.h
@@ -89,7 +89,7 @@ public:
   /// Sends a GDB remote protocol 'A' packet that delivers program
   /// arguments to the remote server.
   ///
-  /// \param[in] argv
+  /// \param[in] launch_info
   ///     A NULL terminated array of const C strings to use as the
   ///     arguments.
   ///
@@ -155,7 +155,7 @@ public:
   /// Sets the path to use for stdin/out/err for a process
   /// that will be launched with the 'A' packet.
   ///
-  /// \param[in] path
+  /// \param[in] file_spec
   ///     The path to use for stdin/out/err
   ///
   /// \return
@@ -596,6 +596,8 @@ protected:
   Status GetQXferMemoryMapRegionInfo(lldb::addr_t addr,
                                      MemoryRegionInfo &region);
 
+  LazyBool GetThreadPacketSupported(lldb::tid_t tid, llvm::StringRef packetStr);
+
 private:
   DISALLOW_COPY_AND_ASSIGN(GDBRemoteCommunicationClient);
 };
diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationHistory.cpp b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationHistory.cpp
index d2cc32f63f20..9e5646985f87 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationHistory.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationHistory.cpp
@@ -40,8 +40,8 @@ void GDBRemoteCommunicationHistory::AddPacket(char packet_char,
   m_packets[idx].bytes_transmitted = bytes_transmitted;
   m_packets[idx].packet_idx = m_total_packet_count;
   m_packets[idx].tid = llvm::get_threadid();
-  if (m_stream)
-    m_packets[idx].Serialize(*m_stream);
+  if (m_recorder)
+    m_recorder->Record(m_packets[idx]);
 }
 
 void GDBRemoteCommunicationHistory::AddPacket(const std::string &src,
@@ -58,8 +58,8 @@ void GDBRemoteCommunicationHistory::AddPacket(const std::string &src,
   m_packets[idx].bytes_transmitted = bytes_transmitted;
   m_packets[idx].packet_idx = m_total_packet_count;
   m_packets[idx].tid = llvm::get_threadid();
-  if (m_stream)
-    m_packets[idx].Serialize(*m_stream);
+  if (m_recorder)
+    m_recorder->Record(m_packets[idx]);
 }
 
 void GDBRemoteCommunicationHistory::Dump(Stream &strm) const {
diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationHistory.h b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationHistory.h
index c006fbd34a4b..ee265ef86dff 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationHistory.h
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationHistory.h
@@ -13,11 +13,15 @@
 #include <vector>
 
 #include "lldb/Utility/GDBRemote.h"
+#include "lldb/Utility/Reproducer.h"
 #include "lldb/lldb-public.h"
 #include "llvm/Support/YAMLTraits.h"
 #include "llvm/Support/raw_ostream.h"
 
 namespace lldb_private {
+namespace repro {
+class PacketRecorder;
+}
 namespace process_gdb_remote {
 
 /// The history keeps a circular buffer of GDB remote packets. The history is
@@ -41,7 +45,7 @@ public:
   void Dump(Log *log) const;
   bool DidDumpToLog() const { return m_dumped_to_log; }
 
-  void SetStream(llvm::raw_ostream *strm) { m_stream = strm; }
+  void SetRecorder(repro::PacketRecorder *recorder) { m_recorder = recorder; }
 
 private:
   uint32_t GetFirstSavedPacketIndex() const {
@@ -73,7 +77,7 @@ private:
   uint32_t m_curr_idx;
   uint32_t m_total_packet_count;
   mutable bool m_dumped_to_log;
-  llvm::raw_ostream *m_stream = nullptr;
+  repro::PacketRecorder *m_recorder = nullptr;
 };
 
 } // namespace process_gdb_remote
diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationReplayServer.cpp b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationReplayServer.cpp
index 2d26c550dc76..15c73e78bd44 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationReplayServer.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationReplayServer.cpp
@@ -143,7 +143,14 @@ GDBRemoteCommunicationReplayServer::GetPacketAndSendResponse(
                  entry.packet.data);
         LLDB_LOG(log, "GDBRemoteCommunicationReplayServer actual packet: '{0}'",
                  packet.GetStringRef());
-        assert(false && "Encountered unexpected packet during replay");
+#ifndef NDEBUG
+        // This behaves like a regular assert, but prints the expected and
+        // received packet before aborting.
+        printf("Reproducer expected packet: '%s'\n", entry.packet.data.c_str());
+        printf("Reproducer received packet: '%s'\n",
+               packet.GetStringRef().data());
+        llvm::report_fatal_error("Encountered unexpected packet during replay");
+#endif
         return PacketResult::ErrorSendFailed;
       }
 
@@ -204,9 +211,9 @@ bool GDBRemoteCommunicationReplayServer::StartAsyncThread() {
         "<lldb.gdb-replay.async>",
         GDBRemoteCommunicationReplayServer::AsyncThread, this);
     if (!async_thread) {
-      LLDB_LOG(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_HOST),
-               "failed to launch host thread: {}",
-               llvm::toString(async_thread.takeError()));
+      LLDB_LOG_ERROR(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_HOST),
+                     async_thread.takeError(),
+                     "failed to launch host thread: {}");
       return false;
     }
     m_async_thread = *async_thread;
diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerCommon.cpp b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerCommon.cpp
index 37980d914dc2..4b5fc0774a6d 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerCommon.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerCommon.cpp
@@ -429,7 +429,7 @@ GDBRemoteCommunicationServerCommon::Handle_qsProcessInfo(
 GDBRemoteCommunication::PacketResult
 GDBRemoteCommunicationServerCommon::Handle_qUserName(
     StringExtractorGDBRemote &packet) {
-#if !defined(LLDB_DISABLE_POSIX)
+#if LLDB_ENABLE_POSIX
   Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_PROCESS));
   LLDB_LOGF(log, "GDBRemoteCommunicationServerCommon::%s begin", __FUNCTION__);
 
@@ -452,7 +452,7 @@ GDBRemoteCommunicationServerCommon::Handle_qUserName(
 GDBRemoteCommunication::PacketResult
 GDBRemoteCommunicationServerCommon::Handle_qGroupName(
     StringExtractorGDBRemote &packet) {
-#if !defined(LLDB_DISABLE_POSIX)
+#if LLDB_ENABLE_POSIX
   // Packet format: "qGroupName:%i" where %i is the gid
   packet.SetFilePos(::strlen("qGroupName:"));
   uint32_t gid = packet.GetU32(UINT32_MAX);
diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp
index ad1a39b57969..f33f0ee66304 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp
@@ -669,9 +669,9 @@ GDBRemoteCommunicationServerLLGS::SendStopReplyPacketForThread(
         response.PutStringAsRawHex8(unescaped_response.GetData());
         response.PutChar(';');
       } else {
-        LLDB_LOG(log, "failed to prepare a jstopinfo field for pid {0}:",
-                 m_debugged_process_up->GetID(),
-                 llvm::toString(threads_info.takeError()));
+        LLDB_LOG_ERROR(log, threads_info.takeError(),
+                       "failed to prepare a jstopinfo field for pid {1}: {0}",
+                       m_debugged_process_up->GetID());
       }
     }
 
@@ -2013,7 +2013,7 @@ GDBRemoteCommunicationServerLLGS::Handle_p(StringExtractorGDBRemote &packet) {
   }
 
   const uint8_t *const data =
-      reinterpret_cast<const uint8_t *>(reg_value.GetBytes());
+      static_cast<const uint8_t *>(reg_value.GetBytes());
   if (!data) {
     LLDB_LOGF(log,
               "GDBRemoteCommunicationServerLLGS::%s failed to get data "
@@ -3087,9 +3087,9 @@ GDBRemoteCommunicationServerLLGS::Handle_jThreadsInfo(
   llvm::Expected<json::Value> threads_info = GetJSONThreadsInfo(
       *m_debugged_process_up, threads_with_valid_stop_info_only);
   if (!threads_info) {
-    LLDB_LOG(log, "failed to prepare a packet for pid {0}: {1}",
-             m_debugged_process_up->GetID(),
-             llvm::toString(threads_info.takeError()));
+    LLDB_LOG_ERROR(log, threads_info.takeError(),
+                   "failed to prepare a packet for pid {1}: {0}",
+                   m_debugged_process_up->GetID());
     return SendErrorResponse(52);
   }
 
diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteRegisterContext.cpp b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteRegisterContext.cpp
index c06c9527708e..ec1a54afd727 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteRegisterContext.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteRegisterContext.cpp
@@ -31,9 +31,11 @@ using namespace lldb_private::process_gdb_remote;
 // GDBRemoteRegisterContext constructor
 GDBRemoteRegisterContext::GDBRemoteRegisterContext(
     ThreadGDBRemote &thread, uint32_t concrete_frame_idx,
-    GDBRemoteDynamicRegisterInfo &reg_info, bool read_all_at_once)
+    GDBRemoteDynamicRegisterInfo &reg_info, bool read_all_at_once,
+    bool write_all_at_once)
     : RegisterContext(thread, concrete_frame_idx), m_reg_info(reg_info),
-      m_reg_valid(), m_reg_data(), m_read_all_at_once(read_all_at_once) {
+      m_reg_valid(), m_reg_data(), m_read_all_at_once(read_all_at_once),
+      m_write_all_at_once(write_all_at_once) {
   // Resize our vector of bools to contain one bool for every register. We will
   // use these boolean values to know when a register value is valid in
   // m_reg_data.
@@ -87,6 +89,9 @@ bool GDBRemoteRegisterContext::ReadRegister(const RegisterInfo *reg_info,
                                             RegisterValue &value) {
   // Read the register
   if (ReadRegisterBytes(reg_info, m_reg_data)) {
+    const uint32_t reg = reg_info->kinds[eRegisterKindLLDB];
+    if (m_reg_valid[reg] == false)
+      return false;
     const bool partial_data_ok = false;
     Status error(value.SetValueFromData(
         reg_info, m_reg_data, reg_info->byte_offset, partial_data_ok));
@@ -203,6 +208,18 @@ bool GDBRemoteRegisterContext::ReadRegisterBytes(const RegisterInfo *reg_info,
         if (buffer_sp->GetByteSize() >= m_reg_data.GetByteSize()) {
           SetAllRegisterValid(true);
           return true;
+        } else if (buffer_sp->GetByteSize() > 0) {
+          const int regcount = m_reg_info.GetNumRegisters();
+          for (int i = 0; i < regcount; i++) {
+            struct RegisterInfo *reginfo = m_reg_info.GetRegisterInfoAtIndex(i);
+            if (reginfo->byte_offset + reginfo->byte_size 
+                   <= buffer_sp->GetByteSize()) {
+              m_reg_valid[i] = true;
+            } else {
+              m_reg_valid[i] = false;
+            }
+          }
+          return true;
         } else {
           Log *log(ProcessGDBRemoteLog::GetLogIfAnyCategoryIsSet(GDBR_LOG_THREAD |
                                                                 GDBR_LOG_PACKETS));
@@ -333,7 +350,7 @@ bool GDBRemoteRegisterContext::WriteRegisterBytes(const RegisterInfo *reg_info,
   {
     GDBRemoteClientBase::Lock lock(gdb_comm, false);
     if (lock) {
-      if (m_read_all_at_once) {
+      if (m_write_all_at_once) {
         // Invalidate all register values
         InvalidateIfNeeded(true);
 
diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteRegisterContext.h b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteRegisterContext.h
index 25e9b716f8cb..b42c87b5991b 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteRegisterContext.h
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteRegisterContext.h
@@ -41,7 +41,7 @@ class GDBRemoteRegisterContext : public RegisterContext {
 public:
   GDBRemoteRegisterContext(ThreadGDBRemote &thread, uint32_t concrete_frame_idx,
                            GDBRemoteDynamicRegisterInfo &reg_info,
-                           bool read_all_at_once);
+                           bool read_all_at_once, bool write_all_at_once);
 
   ~GDBRemoteRegisterContext() override;
 
@@ -114,6 +114,7 @@ protected:
   std::vector<bool> m_reg_valid;
   DataExtractor m_reg_data;
   bool m_read_all_at_once;
+  bool m_write_all_at_once;
 
 private:
   // Helper function for ReadRegisterBytes().
diff --git a/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp b/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
index f1762abc55f8..a49db5d9a934 100644
--- a/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
@@ -10,7 +10,7 @@
 
 #include <errno.h>
 #include <stdlib.h>
-#ifndef LLDB_DISABLE_POSIX
+#if LLDB_ENABLE_POSIX
 #include <netinet/in.h>
 #include <sys/mman.h>
 #include <sys/socket.h>
@@ -154,6 +154,11 @@ public:
         nullptr, idx,
         g_processgdbremote_properties[idx].default_uint_value != 0);
   }
+
+  bool GetUseGPacketForReading() const {
+    const uint32_t idx = ePropertyUseGPacketForReading;
+    return m_collection_sp->GetPropertyAtIndexAsBoolean(nullptr, idx, true);
+  }
 };
 
 typedef std::shared_ptr<PluginProperties> ProcessKDPPropertiesSP;
@@ -274,12 +279,9 @@ ProcessGDBRemote::ProcessGDBRemote(lldb::TargetSP target_sp,
                                    "async thread did exit");
 
   if (repro::Generator *g = repro::Reproducer::Instance().GetGenerator()) {
-    repro::ProcessGDBRemoteProvider &provider =
-        g->GetOrCreate<repro::ProcessGDBRemoteProvider>();
-    // Set the history stream to the stream owned by the provider.
-    m_gdb_comm.SetHistoryStream(provider.GetHistoryStream());
-    // Make sure to clear the stream again when we're finished.
-    provider.SetCallback([&]() { m_gdb_comm.SetHistoryStream(nullptr); });
+    repro::GDBRemoteProvider &provider =
+        g->GetOrCreate<repro::GDBRemoteProvider>();
+    m_gdb_comm.SetPacketRecorder(provider.GetNewPacketRecorder());
   }
 
   Log *log(ProcessGDBRemoteLog::GetLogIfAllCategoriesSet(GDBR_LOG_ASYNC));
@@ -309,6 +311,9 @@ ProcessGDBRemote::ProcessGDBRemote(lldb::TargetSP target_sp,
       GetGlobalPluginProperties()->GetPacketTimeout();
   if (timeout_seconds > 0)
     m_gdb_comm.SetPacketTimeout(std::chrono::seconds(timeout_seconds));
+
+  m_use_g_packet_for_reading =
+      GetGlobalPluginProperties()->GetUseGPacketForReading();
 }
 
 // Destructor
@@ -380,36 +385,6 @@ bool ProcessGDBRemote::ParsePythonTargetDefinition(
   return false;
 }
 
-// If the remote stub didn't give us eh_frame or DWARF register numbers for a
-// register, see if the ABI can provide them.
-// DWARF and eh_frame register numbers are defined as a part of the ABI.
-static void AugmentRegisterInfoViaABI(RegisterInfo &reg_info,
-                                      ConstString reg_name, ABISP abi_sp) {
-  if (reg_info.kinds[eRegisterKindEHFrame] == LLDB_INVALID_REGNUM ||
-      reg_info.kinds[eRegisterKindDWARF] == LLDB_INVALID_REGNUM) {
-    if (abi_sp) {
-      RegisterInfo abi_reg_info;
-      if (abi_sp->GetRegisterInfoByName(reg_name, abi_reg_info)) {
-        if (reg_info.kinds[eRegisterKindEHFrame] == LLDB_INVALID_REGNUM &&
-            abi_reg_info.kinds[eRegisterKindEHFrame] != LLDB_INVALID_REGNUM) {
-          reg_info.kinds[eRegisterKindEHFrame] =
-              abi_reg_info.kinds[eRegisterKindEHFrame];
-        }
-        if (reg_info.kinds[eRegisterKindDWARF] == LLDB_INVALID_REGNUM &&
-            abi_reg_info.kinds[eRegisterKindDWARF] != LLDB_INVALID_REGNUM) {
-          reg_info.kinds[eRegisterKindDWARF] =
-              abi_reg_info.kinds[eRegisterKindDWARF];
-        }
-        if (reg_info.kinds[eRegisterKindGeneric] == LLDB_INVALID_REGNUM &&
-            abi_reg_info.kinds[eRegisterKindGeneric] != LLDB_INVALID_REGNUM) {
-          reg_info.kinds[eRegisterKindGeneric] =
-              abi_reg_info.kinds[eRegisterKindGeneric];
-        }
-      }
-    }
-  }
-}
-
 static size_t SplitCommaSeparatedRegisterNumberString(
     const llvm::StringRef &comma_separated_regiter_numbers,
     std::vector<uint32_t> &regnums, int base) {
@@ -607,12 +582,12 @@ void ProcessGDBRemote::BuildDynamicRegisterInfo(bool force) {
           reg_info.invalidate_regs = invalidate_regs.data();
         }
 
+        reg_info.name = reg_name.AsCString();
         // We have to make a temporary ABI here, and not use the GetABI because
         // this code gets called in DidAttach, when the target architecture
         // (and consequently the ABI we'll get from the process) may be wrong.
-        ABISP abi_to_use = ABI::FindPlugin(shared_from_this(), arch_to_use);
-
-        AugmentRegisterInfoViaABI(reg_info, reg_name, abi_to_use);
+        if (ABISP abi_sp = ABI::FindPlugin(shared_from_this(), arch_to_use))
+          abi_sp->AugmentRegisterInfo(reg_info);
 
         m_register_info.AddRegister(reg_info, reg_name, alt_name, set_name);
       } else {
@@ -2374,21 +2349,22 @@ void ProcessGDBRemote::RefreshStateAfterStop() {
 
   m_thread_ids.clear();
   m_thread_pcs.clear();
+
   // Set the thread stop info. It might have a "threads" key whose value is a
   // list of all thread IDs in the current process, so m_thread_ids might get
   // set.
+  // Check to see if SetThreadStopInfo() filled in m_thread_ids?
+  if (m_thread_ids.empty()) {
+      // No, we need to fetch the thread list manually
+      UpdateThreadIDList();
+  }
+
+  // We might set some stop info's so make sure the thread list is up to
+  // date before we do that or we might overwrite what was computed here.
+  UpdateThreadListIfNeeded();
 
   // Scope for the lock
   {
-    // Check to see if SetThreadStopInfo() filled in m_thread_ids?
-    if (m_thread_ids.empty()) {
-        // No, we need to fetch the thread list manually
-        UpdateThreadIDList();
-    }
-    // We might set some stop info's so make sure the thread list is up to
-    // date before we do that or we might overwrite what was computed here.
-    UpdateThreadListIfNeeded();
-
     // Lock the thread stack while we access it
     std::lock_guard<std::recursive_mutex> guard(m_last_stop_packet_mutex);
     // Get the number of stop packets on the stack
@@ -3384,17 +3360,20 @@ Status ProcessGDBRemote::ConnectToReplayServer(repro::Loader *loader) {
   if (!loader)
     return Status("No loader provided.");
 
-  // Construct replay history path.
-  FileSpec history_file =
-      loader->GetFile<repro::ProcessGDBRemoteProvider::Info>();
-  if (!history_file)
-    return Status("No provider for gdb-remote.");
+  static std::unique_ptr<repro::MultiLoader<repro::GDBRemoteProvider>>
+      multi_loader = repro::MultiLoader<repro::GDBRemoteProvider>::Create(
+          repro::Reproducer::Instance().GetLoader());
 
-  // Enable replay mode.
-  m_replay_mode = true;
+  if (!multi_loader)
+    return Status("No gdb remote provider found.");
+
+  llvm::Optional<std::string> history_file = multi_loader->GetNextFile();
+  if (!history_file)
+    return Status("No gdb remote packet log found.");
 
   // Load replay history.
-  if (auto error = m_gdb_replay_server.LoadReplayHistory(history_file))
+  if (auto error =
+          m_gdb_replay_server.LoadReplayHistory(FileSpec(*history_file)))
     return Status("Unable to load replay history");
 
   // Make a local connection.
@@ -3402,6 +3381,9 @@ Status ProcessGDBRemote::ConnectToReplayServer(repro::Loader *loader) {
                                                           m_gdb_replay_server))
     return Status("Unable to connect to replay server");
 
+  // Enable replay mode.
+  m_replay_mode = true;
+
   // Start server thread.
   m_gdb_replay_server.StartAsyncThread();
 
@@ -3627,9 +3609,9 @@ bool ProcessGDBRemote::StartAsyncThread() {
     llvm::Expected<HostThread> async_thread = ThreadLauncher::LaunchThread(
         "<lldb.process.gdb-remote.async>", ProcessGDBRemote::AsyncThread, this);
     if (!async_thread) {
-      LLDB_LOG(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_HOST),
-               "failed to launch host thread: {}",
-               llvm::toString(async_thread.takeError()));
+      LLDB_LOG_ERROR(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_HOST),
+                     async_thread.takeError(),
+                     "failed to launch host thread: {}");
       return false;
     }
     m_async_thread = *async_thread;
@@ -4475,7 +4457,9 @@ bool ParseRegisters(XMLNode feature_node, GdbServerTargetInfo &target_info,
         }
 
         ++cur_reg_num;
-        AugmentRegisterInfoViaABI(reg_info, reg_name, abi_sp);
+        reg_info.name = reg_name.AsCString();
+        if (abi_sp)
+          abi_sp->AugmentRegisterInfo(reg_info);
         dyn_reg_info.AddRegister(reg_info, reg_name, alt_name, set_name);
 
         return true; // Keep iterating through all "reg" elements
diff --git a/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.h b/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.h
index 0e3e3b39d9c8..9ea3940103b6 100644
--- a/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.h
+++ b/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.h
@@ -284,6 +284,7 @@ protected:
   lldb::CommandObjectSP m_command_sp;
   int64_t m_breakpoint_pc_offset;
   lldb::tid_t m_initial_tid; // The initial thread ID, given by stub on attach
+  bool m_use_g_packet_for_reading;
 
   bool m_replay_mode;
   bool m_allow_flash_writes;
diff --git a/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemoteProperties.td b/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemoteProperties.td
index 16e7723e3061..9cbe3d40ca2c 100644
--- a/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemoteProperties.td
+++ b/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemoteProperties.td
@@ -13,4 +13,8 @@ let Definition = "processgdbremote" in {
     Global,
     DefaultFalse,
     Desc<"If true, the libraries-svr4 feature will be used to get a hold of the process's loaded modules.">;
+  def UseGPacketForReading: Property<"use-g-packet-for-reading", "Boolean">,
+    Global,
+    DefaultFalse,
+    Desc<"Specify if the server should use 'g' packets to read registers.">;
 }
diff --git a/lldb/source/Plugins/Process/gdb-remote/ThreadGDBRemote.cpp b/lldb/source/Plugins/Process/gdb-remote/ThreadGDBRemote.cpp
index 8a6a58c55450..9da481979f73 100644
--- a/lldb/source/Plugins/Process/gdb-remote/ThreadGDBRemote.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/ThreadGDBRemote.cpp
@@ -301,13 +301,14 @@ ThreadGDBRemote::CreateRegisterContextForFrame(StackFrame *frame) {
     if (process_sp) {
       ProcessGDBRemote *gdb_process =
           static_cast<ProcessGDBRemote *>(process_sp.get());
-      // read_all_registers_at_once will be true if 'p' packet is not
-      // supported.
+      bool pSupported =
+          gdb_process->GetGDBRemote().GetpPacketSupported(GetID());
       bool read_all_registers_at_once =
-          !gdb_process->GetGDBRemote().GetpPacketSupported(GetID());
+          !pSupported || gdb_process->m_use_g_packet_for_reading;
+      bool write_all_registers_at_once = !pSupported;
       reg_ctx_sp = std::make_shared<GDBRemoteRegisterContext>(
           *this, concrete_frame_idx, gdb_process->m_register_info,
-          read_all_registers_at_once);
+          read_all_registers_at_once, write_all_registers_at_once);
     }
   } else {
     Unwind *unwinder = GetUnwinder();
diff --git a/lldb/source/Plugins/Process/minidump/MinidumpParser.cpp b/lldb/source/Plugins/Process/minidump/MinidumpParser.cpp
index 70933f91fe51..3c0e1cb49d1d 100644
--- a/lldb/source/Plugins/Process/minidump/MinidumpParser.cpp
+++ b/lldb/source/Plugins/Process/minidump/MinidumpParser.cpp
@@ -174,6 +174,7 @@ ArchSpec MinidumpParser::GetArchitecture() {
     triple.setArch(llvm::Triple::ArchType::arm);
     break;
   case ProcessorArchitecture::ARM64:
+  case ProcessorArchitecture::BP_ARM64:
     triple.setArch(llvm::Triple::ArchType::aarch64);
     break;
   default:
@@ -518,58 +519,26 @@ CreateRegionsCacheFromMemory64List(MinidumpParser &parser,
   return !regions.empty();
 }
 
-MemoryRegionInfo
-MinidumpParser::FindMemoryRegion(lldb::addr_t load_addr) const {
-  auto begin = m_regions.begin();
-  auto end = m_regions.end();
-  auto pos = std::lower_bound(begin, end, load_addr);
-  if (pos != end && pos->GetRange().Contains(load_addr))
-    return *pos;
-  
-  MemoryRegionInfo region;
-  if (pos == begin)
-    region.GetRange().SetRangeBase(0);
-  else {
-    auto prev = pos - 1;
-    if (prev->GetRange().Contains(load_addr))
-      return *prev;
-    region.GetRange().SetRangeBase(prev->GetRange().GetRangeEnd());
-  }
-  if (pos == end)
-    region.GetRange().SetRangeEnd(UINT64_MAX);
-  else
-    region.GetRange().SetRangeEnd(pos->GetRange().GetRangeBase());
-  region.SetReadable(MemoryRegionInfo::eNo);
-  region.SetWritable(MemoryRegionInfo::eNo);
-  region.SetExecutable(MemoryRegionInfo::eNo);
-  region.SetMapped(MemoryRegionInfo::eNo);
-  return region;
-}
-
-MemoryRegionInfo
-MinidumpParser::GetMemoryRegionInfo(lldb::addr_t load_addr) {
-  if (!m_parsed_regions)
-    GetMemoryRegions();
-  return FindMemoryRegion(load_addr);
-}
-
-const MemoryRegionInfos &MinidumpParser::GetMemoryRegions() {
-  if (!m_parsed_regions) {
-    m_parsed_regions = true;
-    // We haven't cached our memory regions yet we will create the region cache
-    // once. We create the region cache using the best source. We start with
-    // the linux maps since they are the most complete and have names for the
-    // regions. Next we try the MemoryInfoList since it has
-    // read/write/execute/map data, and then fall back to the MemoryList and
-    // Memory64List to just get a list of the memory that is mapped in this
-    // core file
-    if (!CreateRegionsCacheFromLinuxMaps(*this, m_regions))
-      if (!CreateRegionsCacheFromMemoryInfoList(*this, m_regions))
-        if (!CreateRegionsCacheFromMemoryList(*this, m_regions))
-          CreateRegionsCacheFromMemory64List(*this, m_regions);
-    llvm::sort(m_regions.begin(), m_regions.end());
-  }
-  return m_regions;
+std::pair<MemoryRegionInfos, bool> MinidumpParser::BuildMemoryRegions() {
+  // We create the region cache using the best source. We start with
+  // the linux maps since they are the most complete and have names for the
+  // regions. Next we try the MemoryInfoList since it has
+  // read/write/execute/map data, and then fall back to the MemoryList and
+  // Memory64List to just get a list of the memory that is mapped in this
+  // core file
+  MemoryRegionInfos result;
+  const auto &return_sorted = [&](bool is_complete) {
+    llvm::sort(result);
+    return std::make_pair(std::move(result), is_complete);
+  };
+  if (CreateRegionsCacheFromLinuxMaps(*this, result))
+    return return_sorted(true);
+  if (CreateRegionsCacheFromMemoryInfoList(*this, result))
+    return return_sorted(true);
+  if (CreateRegionsCacheFromMemoryList(*this, result))
+    return return_sorted(false);
+  CreateRegionsCacheFromMemory64List(*this, result);
+  return return_sorted(false);
 }
 
 #define ENUM_TO_CSTR(ST)                                                       \
diff --git a/lldb/source/Plugins/Process/minidump/MinidumpParser.h b/lldb/source/Plugins/Process/minidump/MinidumpParser.h
index d206fe6c9a00..4bcb2b47d45a 100644
--- a/lldb/source/Plugins/Process/minidump/MinidumpParser.h
+++ b/lldb/source/Plugins/Process/minidump/MinidumpParser.h
@@ -88,9 +88,9 @@ public:
 
   llvm::ArrayRef<uint8_t> GetMemory(lldb::addr_t addr, size_t size);
 
-  MemoryRegionInfo GetMemoryRegionInfo(lldb::addr_t load_addr);
-
-  const MemoryRegionInfos &GetMemoryRegions();
+  /// Returns a list of memory regions and a flag indicating whether the list is
+  /// complete (includes all regions mapped into the process memory).
+  std::pair<MemoryRegionInfos, bool> BuildMemoryRegions();
 
   static llvm::StringRef GetStreamTypeAsString(StreamType stream_type);
 
@@ -100,14 +100,10 @@ private:
   MinidumpParser(lldb::DataBufferSP data_sp,
                  std::unique_ptr<llvm::object::MinidumpFile> file);
 
-  MemoryRegionInfo FindMemoryRegion(lldb::addr_t load_addr) const;
-
 private:
   lldb::DataBufferSP m_data_sp;
   std::unique_ptr<llvm::object::MinidumpFile> m_file;
   ArchSpec m_arch;
-  MemoryRegionInfos m_regions;
-  bool m_parsed_regions = false;
 };
 
 } // end namespace minidump
diff --git a/lldb/source/Plugins/Process/minidump/ProcessMinidump.cpp b/lldb/source/Plugins/Process/minidump/ProcessMinidump.cpp
index e30a3c82a887..5c090dc6e12f 100644
--- a/lldb/source/Plugins/Process/minidump/ProcessMinidump.cpp
+++ b/lldb/source/Plugins/Process/minidump/ProcessMinidump.cpp
@@ -334,15 +334,84 @@ ArchSpec ProcessMinidump::GetArchitecture() {
   return ArchSpec(triple);
 }
 
+static MemoryRegionInfo GetMemoryRegionInfo(const MemoryRegionInfos &regions,
+                                            lldb::addr_t load_addr) {
+  MemoryRegionInfo region;
+  auto pos = llvm::upper_bound(regions, load_addr);
+  if (pos != regions.begin() &&
+      std::prev(pos)->GetRange().Contains(load_addr)) {
+    return *std::prev(pos);
+  }
+
+  if (pos == regions.begin())
+    region.GetRange().SetRangeBase(0);
+  else
+    region.GetRange().SetRangeBase(std::prev(pos)->GetRange().GetRangeEnd());
+
+  if (pos == regions.end())
+    region.GetRange().SetRangeEnd(UINT64_MAX);
+  else
+    region.GetRange().SetRangeEnd(pos->GetRange().GetRangeBase());
+
+  region.SetReadable(MemoryRegionInfo::eNo);
+  region.SetWritable(MemoryRegionInfo::eNo);
+  region.SetExecutable(MemoryRegionInfo::eNo);
+  region.SetMapped(MemoryRegionInfo::eNo);
+  return region;
+}
+
+void ProcessMinidump::BuildMemoryRegions() {
+  if (m_memory_regions)
+    return;
+  m_memory_regions.emplace();
+  bool is_complete;
+  std::tie(*m_memory_regions, is_complete) =
+      m_minidump_parser->BuildMemoryRegions();
+
+  if (is_complete)
+    return;
+
+  MemoryRegionInfos to_add;
+  ModuleList &modules = GetTarget().GetImages();
+  SectionLoadList &load_list = GetTarget().GetSectionLoadList();
+  modules.ForEach([&](const ModuleSP &module_sp) {
+    SectionList *sections = module_sp->GetSectionList();
+    for (size_t i = 0; i < sections->GetSize(); ++i) {
+      SectionSP section_sp = sections->GetSectionAtIndex(i);
+      addr_t load_addr = load_list.GetSectionLoadAddress(section_sp);
+      if (load_addr == LLDB_INVALID_ADDRESS)
+        continue;
+      MemoryRegionInfo::RangeType section_range(load_addr,
+                                                section_sp->GetByteSize());
+      MemoryRegionInfo region =
+          ::GetMemoryRegionInfo(*m_memory_regions, load_addr);
+      if (region.GetMapped() != MemoryRegionInfo::eYes &&
+          region.GetRange().GetRangeBase() <= section_range.GetRangeBase() &&
+          section_range.GetRangeEnd() <= region.GetRange().GetRangeEnd()) {
+        to_add.emplace_back();
+        to_add.back().GetRange() = section_range;
+        to_add.back().SetLLDBPermissions(section_sp->GetPermissions());
+        to_add.back().SetMapped(MemoryRegionInfo::eYes);
+        to_add.back().SetName(module_sp->GetFileSpec().GetPath().c_str());
+      }
+    }
+    return true;
+  });
+  m_memory_regions->insert(m_memory_regions->end(), to_add.begin(),
+                           to_add.end());
+  llvm::sort(*m_memory_regions);
+}
+
 Status ProcessMinidump::GetMemoryRegionInfo(lldb::addr_t load_addr,
-                                            MemoryRegionInfo &range_info) {
-  range_info = m_minidump_parser->GetMemoryRegionInfo(load_addr);
+                                            MemoryRegionInfo &region) {
+  BuildMemoryRegions();
+  region = ::GetMemoryRegionInfo(*m_memory_regions, load_addr);
   return Status();
 }
 
-Status ProcessMinidump::GetMemoryRegions(
-    lldb_private::MemoryRegionInfos &region_list) {
-  region_list = m_minidump_parser->GetMemoryRegions();
+Status ProcessMinidump::GetMemoryRegions(MemoryRegionInfos &region_list) {
+  BuildMemoryRegions();
+  region_list = *m_memory_regions;
   return Status();
 }
 
diff --git a/lldb/source/Plugins/Process/minidump/ProcessMinidump.h b/lldb/source/Plugins/Process/minidump/ProcessMinidump.h
index 22dc24af7c0e..750164cf8aaf 100644
--- a/lldb/source/Plugins/Process/minidump/ProcessMinidump.h
+++ b/lldb/source/Plugins/Process/minidump/ProcessMinidump.h
@@ -111,6 +111,9 @@ private:
   const minidump::ExceptionStream *m_active_exception;
   lldb::CommandObjectSP m_command_sp;
   bool m_is_wow64;
+  llvm::Optional<MemoryRegionInfos> m_memory_regions;
+
+  void BuildMemoryRegions();
 };
 
 } // namespace minidump
diff --git a/lldb/source/Plugins/ScriptInterpreter/Lua/Lua.cpp b/lldb/source/Plugins/ScriptInterpreter/Lua/Lua.cpp
new file mode 100644
index 000000000000..ecee8cc674f8
--- /dev/null
+++ b/lldb/source/Plugins/ScriptInterpreter/Lua/Lua.cpp
@@ -0,0 +1,59 @@
+//===-- Lua.cpp -----------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "Lua.h"
+#include "lldb/Host/FileSystem.h"
+#include "lldb/Utility/FileSpec.h"
+#include "llvm/Support/FormatVariadic.h"
+
+using namespace lldb_private;
+using namespace lldb;
+
+llvm::Error Lua::Run(llvm::StringRef buffer) {
+  int error =
+      luaL_loadbuffer(m_lua_state, buffer.data(), buffer.size(), "buffer") ||
+      lua_pcall(m_lua_state, 0, 0, 0);
+  if (!error)
+    return llvm::Error::success();
+
+  llvm::Error e = llvm::make_error<llvm::StringError>(
+      llvm::formatv("{0}\n", lua_tostring(m_lua_state, -1)),
+      llvm::inconvertibleErrorCode());
+  // Pop error message from the stack.
+  lua_pop(m_lua_state, 1);
+  return e;
+}
+
+llvm::Error Lua::LoadModule(llvm::StringRef filename) {
+  FileSpec file(filename);
+  if (!FileSystem::Instance().Exists(file)) {
+    return llvm::make_error<llvm::StringError>("invalid path",
+                                               llvm::inconvertibleErrorCode());
+  }
+
+  ConstString module_extension = file.GetFileNameExtension();
+  if (module_extension != ".lua") {
+    return llvm::make_error<llvm::StringError>("invalid extension",
+                                               llvm::inconvertibleErrorCode());
+  }
+
+  int error = luaL_loadfile(m_lua_state, filename.data()) ||
+              lua_pcall(m_lua_state, 0, 1, 0);
+  if (error) {
+    llvm::Error e = llvm::make_error<llvm::StringError>(
+        llvm::formatv("{0}\n", lua_tostring(m_lua_state, -1)),
+        llvm::inconvertibleErrorCode());
+    // Pop error message from the stack.
+    lua_pop(m_lua_state, 1);
+    return e;
+  }
+
+  ConstString module_name = file.GetFileNameStrippingExtension();
+  lua_setglobal(m_lua_state, module_name.GetCString());
+  return llvm::Error::success();
+}
diff --git a/lldb/source/Plugins/ScriptInterpreter/Lua/Lua.h b/lldb/source/Plugins/ScriptInterpreter/Lua/Lua.h
new file mode 100644
index 000000000000..f2984a925dfe
--- /dev/null
+++ b/lldb/source/Plugins/ScriptInterpreter/Lua/Lua.h
@@ -0,0 +1,48 @@
+//===-- ScriptInterpreterLua.h ----------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef liblldb_Lua_h_
+#define liblldb_Lua_h_
+
+#include "lldb/lldb-types.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Support/Error.h"
+
+#include "lua.hpp"
+
+#include <mutex>
+
+namespace lldb_private {
+
+extern "C" {
+int luaopen_lldb(lua_State *L);
+}
+
+class Lua {
+public:
+  Lua() : m_lua_state(luaL_newstate()) {
+    assert(m_lua_state);
+    luaL_openlibs(m_lua_state);
+    luaopen_lldb(m_lua_state);
+  }
+
+  ~Lua() {
+    assert(m_lua_state);
+    luaL_openlibs(m_lua_state);
+  }
+
+  llvm::Error Run(llvm::StringRef buffer);
+  llvm::Error LoadModule(llvm::StringRef filename);
+
+private:
+  lua_State *m_lua_state;
+};
+
+} // namespace lldb_private
+
+#endif // liblldb_Lua_h_
diff --git a/lldb/source/Plugins/ScriptInterpreter/Lua/ScriptInterpreterLua.cpp b/lldb/source/Plugins/ScriptInterpreter/Lua/ScriptInterpreterLua.cpp
new file mode 100644
index 000000000000..701d68d1ec08
--- /dev/null
+++ b/lldb/source/Plugins/ScriptInterpreter/Lua/ScriptInterpreterLua.cpp
@@ -0,0 +1,157 @@
+//===-- ScriptInterpreterLua.cpp --------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "ScriptInterpreterLua.h"
+#include "Lua.h"
+#include "lldb/Core/Debugger.h"
+#include "lldb/Core/PluginManager.h"
+#include "lldb/Core/StreamFile.h"
+#include "lldb/Interpreter/CommandReturnObject.h"
+#include "lldb/Utility/Stream.h"
+#include "lldb/Utility/StringList.h"
+#include "lldb/Utility/Timer.h"
+
+using namespace lldb;
+using namespace lldb_private;
+
+class IOHandlerLuaInterpreter : public IOHandlerDelegate,
+                                public IOHandlerEditline {
+public:
+  IOHandlerLuaInterpreter(Debugger &debugger,
+                          ScriptInterpreterLua &script_interpreter)
+      : IOHandlerEditline(debugger, IOHandler::Type::LuaInterpreter, "lua",
+                          ">>> ", "..> ", true, debugger.GetUseColor(), 0,
+                          *this, nullptr),
+        m_script_interpreter(script_interpreter) {
+    llvm::cantFail(m_script_interpreter.EnterSession(debugger.GetID()));
+  }
+
+  ~IOHandlerLuaInterpreter() {
+    llvm::cantFail(m_script_interpreter.LeaveSession());
+  }
+
+  void IOHandlerInputComplete(IOHandler &io_handler,
+                              std::string &data) override {
+    if (llvm::Error error = m_script_interpreter.GetLua().Run(data)) {
+      *GetOutputStreamFileSP() << llvm::toString(std::move(error));
+    }
+  }
+
+private:
+  ScriptInterpreterLua &m_script_interpreter;
+};
+
+ScriptInterpreterLua::ScriptInterpreterLua(Debugger &debugger)
+    : ScriptInterpreter(debugger, eScriptLanguageLua),
+      m_lua(std::make_unique<Lua>()) {}
+
+ScriptInterpreterLua::~ScriptInterpreterLua() {}
+
+bool ScriptInterpreterLua::ExecuteOneLine(llvm::StringRef command,
+                                          CommandReturnObject *result,
+                                          const ExecuteScriptOptions &options) {
+  if (llvm::Error e = m_lua->Run(command)) {
+    result->AppendErrorWithFormatv(
+        "lua failed attempting to evaluate '{0}': {1}\n", command,
+        llvm::toString(std::move(e)));
+    return false;
+  }
+  return true;
+}
+
+void ScriptInterpreterLua::ExecuteInterpreterLoop() {
+  static Timer::Category func_cat(LLVM_PRETTY_FUNCTION);
+  Timer scoped_timer(func_cat, LLVM_PRETTY_FUNCTION);
+
+  Debugger &debugger = m_debugger;
+
+  // At the moment, the only time the debugger does not have an input file
+  // handle is when this is called directly from lua, in which case it is
+  // both dangerous and unnecessary (not to mention confusing) to try to embed
+  // a running interpreter loop inside the already running lua interpreter
+  // loop, so we won't do it.
+
+  if (!debugger.GetInputFile().IsValid())
+    return;
+
+  IOHandlerSP io_handler_sp(new IOHandlerLuaInterpreter(debugger, *this));
+  debugger.PushIOHandler(io_handler_sp);
+}
+
+bool ScriptInterpreterLua::LoadScriptingModule(
+    const char *filename, bool init_session, lldb_private::Status &error,
+    StructuredData::ObjectSP *module_sp) {
+
+  if (llvm::Error e = m_lua->LoadModule(filename)) {
+    error.SetErrorStringWithFormatv("lua failed to import '{0}': {1}\n",
+                                    filename, llvm::toString(std::move(e)));
+    return false;
+  }
+  return true;
+}
+
+void ScriptInterpreterLua::Initialize() {
+  static llvm::once_flag g_once_flag;
+
+  llvm::call_once(g_once_flag, []() {
+    PluginManager::RegisterPlugin(GetPluginNameStatic(),
+                                  GetPluginDescriptionStatic(),
+                                  lldb::eScriptLanguageLua, CreateInstance);
+  });
+}
+
+void ScriptInterpreterLua::Terminate() {}
+
+llvm::Error ScriptInterpreterLua::EnterSession(user_id_t debugger_id) {
+  if (m_session_is_active)
+    return llvm::Error::success();
+
+  const char *fmt_str =
+      "lldb.debugger = lldb.SBDebugger.FindDebuggerWithID({0}); "
+      "lldb.target = lldb.debugger:GetSelectedTarget(); "
+      "lldb.process = lldb.target:GetProcess(); "
+      "lldb.thread = lldb.process:GetSelectedThread(); "
+      "lldb.frame = lldb.thread:GetSelectedFrame()";
+  return m_lua->Run(llvm::formatv(fmt_str, debugger_id).str());
+}
+
+llvm::Error ScriptInterpreterLua::LeaveSession() {
+  if (!m_session_is_active)
+    return llvm::Error::success();
+
+  m_session_is_active = false;
+
+  llvm::StringRef str = "lldb.debugger = nil; "
+                        "lldb.target = nil; "
+                        "lldb.process = nil; "
+                        "lldb.thread = nil; "
+                        "lldb.frame = nil";
+  return m_lua->Run(str);
+}
+
+lldb::ScriptInterpreterSP
+ScriptInterpreterLua::CreateInstance(Debugger &debugger) {
+  return std::make_shared<ScriptInterpreterLua>(debugger);
+}
+
+lldb_private::ConstString ScriptInterpreterLua::GetPluginNameStatic() {
+  static ConstString g_name("script-lua");
+  return g_name;
+}
+
+const char *ScriptInterpreterLua::GetPluginDescriptionStatic() {
+  return "Lua script interpreter";
+}
+
+lldb_private::ConstString ScriptInterpreterLua::GetPluginName() {
+  return GetPluginNameStatic();
+}
+
+uint32_t ScriptInterpreterLua::GetPluginVersion() { return 1; }
+
+Lua &ScriptInterpreterLua::GetLua() { return *m_lua; }
diff --git a/lldb/source/Plugins/ScriptInterpreter/Lua/ScriptInterpreterLua.h b/lldb/source/Plugins/ScriptInterpreter/Lua/ScriptInterpreterLua.h
new file mode 100644
index 000000000000..4e922151385b
--- /dev/null
+++ b/lldb/source/Plugins/ScriptInterpreter/Lua/ScriptInterpreterLua.h
@@ -0,0 +1,61 @@
+//===-- ScriptInterpreterLua.h ----------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef liblldb_ScriptInterpreterLua_h_
+#define liblldb_ScriptInterpreterLua_h_
+
+#include "lldb/Interpreter/ScriptInterpreter.h"
+
+namespace lldb_private {
+class Lua;
+class ScriptInterpreterLua : public ScriptInterpreter {
+public:
+  ScriptInterpreterLua(Debugger &debugger);
+
+  ~ScriptInterpreterLua() override;
+
+  bool ExecuteOneLine(
+      llvm::StringRef command, CommandReturnObject *result,
+      const ExecuteScriptOptions &options = ExecuteScriptOptions()) override;
+
+  void ExecuteInterpreterLoop() override;
+
+  virtual bool
+  LoadScriptingModule(const char *filename, bool init_session,
+                      lldb_private::Status &error,
+                      StructuredData::ObjectSP *module_sp = nullptr) override;
+
+  // Static Functions
+  static void Initialize();
+
+  static void Terminate();
+
+  static lldb::ScriptInterpreterSP CreateInstance(Debugger &debugger);
+
+  static lldb_private::ConstString GetPluginNameStatic();
+
+  static const char *GetPluginDescriptionStatic();
+
+  // PluginInterface protocol
+  lldb_private::ConstString GetPluginName() override;
+
+  uint32_t GetPluginVersion() override;
+
+  Lua &GetLua();
+
+  llvm::Error EnterSession(lldb::user_id_t debugger_id);
+  llvm::Error LeaveSession();
+
+private:
+  std::unique_ptr<Lua> m_lua;
+  bool m_session_is_active = false;
+};
+
+} // namespace lldb_private
+
+#endif // liblldb_ScriptInterpreterLua_h_
diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/PythonDataObjects.cpp b/lldb/source/Plugins/ScriptInterpreter/Python/PythonDataObjects.cpp
index 70d93424fdec..e5a67653e334 100644
--- a/lldb/source/Plugins/ScriptInterpreter/Python/PythonDataObjects.cpp
+++ b/lldb/source/Plugins/ScriptInterpreter/Python/PythonDataObjects.cpp
@@ -6,11 +6,9 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifdef LLDB_DISABLE_PYTHON
+#include "lldb/Host/Config.h"
 
-// Python is disabled in this build
-
-#else
+#if LLDB_ENABLE_PYTHON
 
 #include "PythonDataObjects.h"
 #include "ScriptInterpreterPython.h"
@@ -802,29 +800,11 @@ bool PythonCallable::Check(PyObject *py_obj) {
   return PyCallable_Check(py_obj);
 }
 
-PythonCallable::ArgInfo PythonCallable::GetNumInitArguments() const {
-  auto arginfo = GetInitArgInfo();
-  if (!arginfo) {
-    llvm::consumeError(arginfo.takeError());
-    return ArgInfo{};
-  }
-  return arginfo.get();
-}
-
-Expected<PythonCallable::ArgInfo> PythonCallable::GetInitArgInfo() const {
-  if (!IsValid())
-    return nullDeref();
-  auto init = As<PythonCallable>(GetAttribute("__init__"));
-  if (!init)
-    return init.takeError();
-  return init.get().GetArgInfo();
-}
-
 #if PY_MAJOR_VERSION >= 3 && PY_MINOR_VERSION >= 3
 static const char get_arg_info_script[] = R"(
 from inspect import signature, Parameter, ismethod
 from collections import namedtuple
-ArgInfo = namedtuple('ArgInfo', ['count', 'has_varargs', 'is_bound_method'])
+ArgInfo = namedtuple('ArgInfo', ['count', 'has_varargs'])
 def main(f):
     count = 0
     varargs = False
@@ -840,7 +820,7 @@ def main(f):
             pass
         else:
             raise Exception(f'unknown parameter kind: {kind}')
-    return ArgInfo(count, varargs, ismethod(f))
+    return ArgInfo(count, varargs)
 )";
 #endif
 
@@ -856,21 +836,27 @@ Expected<PythonCallable::ArgInfo> PythonCallable::GetArgInfo() const {
   Expected<PythonObject> pyarginfo = get_arg_info(*this);
   if (!pyarginfo)
     return pyarginfo.takeError();
-  result.count = cantFail(As<long long>(pyarginfo.get().GetAttribute("count")));
-  result.has_varargs =
+  long long count =
+      cantFail(As<long long>(pyarginfo.get().GetAttribute("count")));
+  bool has_varargs =
       cantFail(As<bool>(pyarginfo.get().GetAttribute("has_varargs")));
-  bool is_method =
-      cantFail(As<bool>(pyarginfo.get().GetAttribute("is_bound_method")));
-  result.max_positional_args =
-      result.has_varargs ? ArgInfo::UNBOUNDED : result.count;
-
-  // FIXME emulate old broken behavior
-  if (is_method)
-    result.count++;
+  result.max_positional_args = has_varargs ? ArgInfo::UNBOUNDED : count;
 
 #else
+  PyObject *py_func_obj;
   bool is_bound_method = false;
-  PyObject *py_func_obj = m_py_obj;
+  bool is_class = false;
+
+  if (PyType_Check(m_py_obj) || PyClass_Check(m_py_obj)) {
+    auto init = GetAttribute("__init__");
+    if (!init)
+      return init.takeError();
+    py_func_obj = init.get().get();
+    is_class = true;
+  } else {
+    py_func_obj = m_py_obj;
+  }
+
   if (PyMethod_Check(py_func_obj)) {
     py_func_obj = PyMethod_GET_FUNCTION(py_func_obj);
     PythonObject im_self = GetAttributeValue("im_self");
@@ -899,11 +885,11 @@ Expected<PythonCallable::ArgInfo> PythonCallable::GetArgInfo() const {
   if (!code)
     return result;
 
-  result.count = code->co_argcount;
-  result.has_varargs = !!(code->co_flags & CO_VARARGS);
-  result.max_positional_args = result.has_varargs
-                                   ? ArgInfo::UNBOUNDED
-                                   : (result.count - (int)is_bound_method);
+  auto count = code->co_argcount;
+  bool has_varargs = !!(code->co_flags & CO_VARARGS);
+  result.max_positional_args =
+      has_varargs ? ArgInfo::UNBOUNDED
+                  : (count - (int)is_bound_method) - (int)is_class;
 
 #endif
 
@@ -913,15 +899,6 @@ Expected<PythonCallable::ArgInfo> PythonCallable::GetArgInfo() const {
 constexpr unsigned
     PythonCallable::ArgInfo::UNBOUNDED; // FIXME delete after c++17
 
-PythonCallable::ArgInfo PythonCallable::GetNumArguments() const {
-  auto arginfo = GetArgInfo();
-  if (!arginfo) {
-    llvm::consumeError(arginfo.takeError());
-    return ArgInfo{};
-  }
-  return arginfo.get();
-}
-
 PythonObject PythonCallable::operator()() {
   return PythonObject(PyRefType::Owned, PyObject_CallObject(m_py_obj, nullptr));
 }
@@ -1385,11 +1362,13 @@ llvm::Expected<FileSP> PythonFile::ConvertToFile(bool borrowed) {
   if (!options)
     return options.takeError();
 
-  // LLDB and python will not share I/O buffers.  We should probably
-  // flush the python buffers now.
-  auto r = CallMethod("flush");
-  if (!r)
-    return r.takeError();
+  if (options.get() & File::eOpenOptionWrite) {
+    // LLDB and python will not share I/O buffers.  We should probably
+    // flush the python buffers now.
+    auto r = CallMethod("flush");
+    if (!r)
+      return r.takeError();
+  }
 
   FileSP file_sp;
   if (borrowed) {
@@ -1498,14 +1477,23 @@ Expected<PythonFile> PythonFile::FromFile(File &file, const char *mode) {
   PyObject *file_obj;
 #if PY_MAJOR_VERSION >= 3
   file_obj = PyFile_FromFd(file.GetDescriptor(), nullptr, mode, -1, nullptr,
-                           "ignore", nullptr, 0);
+                           "ignore", nullptr, /*closefd=*/0);
 #else
-  // Read through the Python source, doesn't seem to modify these strings
-  char *cmode = const_cast<char *>(mode);
-  // We pass ::flush instead of ::fclose here so we borrow the FILE* --
-  // the lldb_private::File still owns it.
-  file_obj =
-      PyFile_FromFile(file.GetStream(), const_cast<char *>(""), cmode, ::fflush);
+  // I'd like to pass ::fflush here if the file is writable,  so that
+  // when the python side destructs the file object it will be flushed.
+  // However, this would be dangerous.    It can cause fflush to be called
+  // after fclose if the python program keeps a reference to the file after
+  // the original lldb_private::File has been destructed.
+  //
+  // It's all well and good to ask a python program not to use a closed file
+  // but asking a python program to make sure objects get released in a
+  // particular order is not safe.
+  //
+  // The tradeoff here is that if a python 2 program wants to make sure this
+  // file gets flushed, they'll have to do it explicitly or wait untill the
+  // original lldb File itself gets flushed.
+  file_obj = PyFile_FromFile(file.GetStream(), py2_const_cast(""),
+                             py2_const_cast(mode), [](FILE *) { return 0; });
 #endif
 
   if (!file_obj)
diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/PythonDataObjects.h b/lldb/source/Plugins/ScriptInterpreter/Python/PythonDataObjects.h
index 373d3212697d..b75045b239a8 100644
--- a/lldb/source/Plugins/ScriptInterpreter/Python/PythonDataObjects.h
+++ b/lldb/source/Plugins/ScriptInterpreter/Python/PythonDataObjects.h
@@ -48,7 +48,9 @@
 #ifndef LLDB_PLUGINS_SCRIPTINTERPRETER_PYTHON_PYTHONDATAOBJECTS_H
 #define LLDB_PLUGINS_SCRIPTINTERPRETER_PYTHON_PYTHONDATAOBJECTS_H
 
-#ifndef LLDB_DISABLE_PYTHON
+#include "lldb/Host/Config.h"
+
+#if LLDB_ENABLE_PYTHON
 
 // LLDB Python header must be included first
 #include "lldb-python.h"
@@ -130,7 +132,7 @@ template <typename T> T Take(PyObject *obj) {
   assert(!PyErr_Occurred());
   T thing(PyRefType::Owned, obj);
   assert(thing.IsValid());
-  return std::move(thing);
+  return thing;
 }
 
 // Retain a reference you have borrowed, and turn it into
@@ -148,7 +150,7 @@ template <typename T> T Retain(PyObject *obj) {
   assert(!PyErr_Occurred());
   T thing(PyRefType::Borrowed, obj);
   assert(thing.IsValid());
-  return std::move(thing);
+  return thing;
 }
 
 // This class can be used like a utility function to convert from
@@ -189,6 +191,14 @@ inline llvm::Error keyError() {
                                  "key not in dict");
 }
 
+#if PY_MAJOR_VERSION < 3
+// The python 2 API declares some arguments as char* that should
+// be const char *, but it doesn't actually modify them.
+inline char *py2_const_cast(const char *s) { return const_cast<char *>(s); }
+#else
+inline const char *py2_const_cast(const char *s) { return s; }
+#endif
+
 enum class PyInitialValue { Invalid, Empty };
 
 template <typename T, typename Enable = void> struct PythonFormat;
@@ -309,16 +319,6 @@ public:
 
   StructuredData::ObjectSP CreateStructuredObject() const;
 
-protected:
-
-#if PY_MAJOR_VERSION < 3
-  // The python 2 API declares some arguments as char* that should
-  // be const char *, but it doesn't actually modify them.
-  static char *py2_const_cast(const char *s) { return const_cast<char *>(s); }
-#else
-  static const char *py2_const_cast(const char *s) { return s; }
-#endif
-
 public:
   template <typename... T>
   llvm::Expected<PythonObject> CallMethod(const char *name,
@@ -621,30 +621,12 @@ public:
      * function and can accept an arbitrary number */
     unsigned max_positional_args;
     static constexpr unsigned UNBOUNDED = UINT_MAX; // FIXME c++17 inline
-    /* the number of positional arguments, including optional ones,
-     * and excluding varargs.  If this is a bound method, then the
-     * count will still include a +1 for self.
-     *
-     * FIXME. That's crazy.  This should be replaced with
-     * an accurate min and max for positional args.
-     */
-    int count;
-    /* does the callable have positional varargs? */
-    bool has_varargs : 1; // FIXME delete this
   };
 
   static bool Check(PyObject *py_obj);
 
   llvm::Expected<ArgInfo> GetArgInfo() const;
 
-  llvm::Expected<ArgInfo> GetInitArgInfo() const;
-
-  ArgInfo GetNumArguments() const; // DEPRECATED
-
-  // If the callable is a Py_Class, then find the number of arguments
-  // of the __init__ method.
-  ArgInfo GetNumInitArguments() const; // DEPRECATED
-
   PythonObject operator()();
 
   PythonObject operator()(std::initializer_list<PyObject *> args);
diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/PythonReadline.cpp b/lldb/source/Plugins/ScriptInterpreter/Python/PythonReadline.cpp
new file mode 100644
index 000000000000..5f6429f5cd0e
--- /dev/null
+++ b/lldb/source/Plugins/ScriptInterpreter/Python/PythonReadline.cpp
@@ -0,0 +1,88 @@
+#include "PythonReadline.h"
+
+#ifdef LLDB_USE_LIBEDIT_READLINE_COMPAT_MODULE
+
+#include <stdio.h>
+
+#include <editline/readline.h>
+
+// Simple implementation of the Python readline module using libedit.
+// In the event that libedit is excluded from the build, this turns
+// back into a null implementation that blocks the module from pulling
+// in the GNU readline shared lib, which causes linkage confusion when
+// both readline and libedit's readline compatibility symbols collide.
+//
+// Currently it only installs a PyOS_ReadlineFunctionPointer, without
+// implementing any of the readline module methods. This is meant to
+// work around LLVM pr18841 to avoid seg faults in the stock Python
+// readline.so linked against GNU readline.
+//
+// Bug on the cpython side: https://bugs.python.org/issue38634
+
+PyDoc_STRVAR(moduleDocumentation,
+             "Simple readline module implementation based on libedit.");
+
+#if PY_MAJOR_VERSION >= 3
+static struct PyModuleDef readline_module = {
+    PyModuleDef_HEAD_INIT, // m_base
+    "lldb_editline",       // m_name
+    moduleDocumentation,   // m_doc
+    -1,                    // m_size
+    nullptr,               // m_methods
+    nullptr,               // m_reload
+    nullptr,               // m_traverse
+    nullptr,               // m_clear
+    nullptr,               // m_free
+};
+#else
+static struct PyMethodDef moduleMethods[] = {{nullptr, nullptr, 0, nullptr}};
+#endif
+
+static char *
+#if PY_MAJOR_VERSION >= 3
+simple_readline(FILE *stdin, FILE *stdout, const char *prompt)
+#else
+simple_readline(FILE *stdin, FILE *stdout, char *prompt)
+#endif
+{
+  rl_instream = stdin;
+  rl_outstream = stdout;
+  char *line = readline(prompt);
+  if (!line) {
+#if PY_MAJOR_VERSION >= 3
+    char *ret = (char *)PyMem_RawMalloc(1);
+#else
+    char *ret = (char *)PyMem_Malloc(1);
+#endif
+    if (ret != NULL)
+      *ret = '\0';
+    return ret;
+  }
+  if (*line)
+    add_history(line);
+  int n = strlen(line);
+#if PY_MAJOR_VERSION >= 3
+  char *ret = (char *)PyMem_RawMalloc(n + 2);
+#else
+  char *ret = (char *)PyMem_Malloc(n + 2);
+#endif
+  if (ret) {
+    memcpy(ret, line, n);
+    free(line);
+    ret[n] = '\n';
+    ret[n + 1] = '\0';
+  }
+  return ret;
+}
+
+PyMODINIT_FUNC initlldb_readline(void) {
+  PyOS_ReadlineFunctionPointer = simple_readline;
+
+#if PY_MAJOR_VERSION >= 3
+  return PyModule_Create(&readline_module);
+#else
+  Py_InitModule4("readline", moduleMethods, moduleDocumentation,
+                 static_cast<PyObject *>(NULL), PYTHON_API_VERSION);
+#endif
+}
+#endif
diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/PythonReadline.h b/lldb/source/Plugins/ScriptInterpreter/Python/PythonReadline.h
new file mode 100644
index 000000000000..c75219eb1a4f
--- /dev/null
+++ b/lldb/source/Plugins/ScriptInterpreter/Python/PythonReadline.h
@@ -0,0 +1,28 @@
+//===-- PythonReadline.h ----------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLDB_PLUGINS_SCRIPTINTERPRETER_PYTHON_PYTHONREADLINE_H
+#define LLDB_PLUGINS_SCRIPTINTERPRETER_PYTHON_PYTHONREADLINE_H
+
+#include "lldb/Host/Config.h"
+
+#if LLDB_ENABLE_LIBEDIT && defined(__linux__)
+// NOTE: Since Python may define some pre-processor definitions which affect the
+// standard headers on some systems, you must include Python.h before any
+// standard headers are included.
+#include "Python.h"
+
+// no need to hack into Python's readline module if libedit isn't used.
+//
+#define LLDB_USE_LIBEDIT_READLINE_COMPAT_MODULE 1
+
+PyMODINIT_FUNC initlldb_readline(void);
+
+#endif
+
+#endif // LLDB_PLUGINS_SCRIPTINTERPRETER_PYTHON_PYTHONREADLINE_H
diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.cpp b/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.cpp
index 3eee52184142..06e0d5bfa63f 100644
--- a/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.cpp
+++ b/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.cpp
@@ -6,16 +6,15 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifdef LLDB_DISABLE_PYTHON
+#include "lldb/Host/Config.h"
 
-// Python is disabled in this build
-
-#else
+#if LLDB_ENABLE_PYTHON
 
 // LLDB Python header must be included first
 #include "lldb-python.h"
 
 #include "PythonDataObjects.h"
+#include "PythonReadline.h"
 #include "ScriptInterpreterPythonImpl.h"
 
 #include "lldb/API/SBFrame.h"
@@ -72,10 +71,28 @@ extern "C" void init_lldb(void);
 // These prototypes are the Pythonic implementations of the required callbacks.
 // Although these are scripting-language specific, their definition depends on
 // the public API.
-extern "C" bool LLDBSwigPythonBreakpointCallbackFunction(
+
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wreturn-type-c-linkage"
+
+// Disable warning C4190: 'LLDBSwigPythonBreakpointCallbackFunction' has
+// C-linkage specified, but returns UDT 'llvm::Expected<bool>' which is
+// incompatible with C
+#if _MSC_VER
+#pragma warning (push)
+#pragma warning (disable : 4190)
+#endif
+
+extern "C" llvm::Expected<bool> LLDBSwigPythonBreakpointCallbackFunction(
     const char *python_function_name, const char *session_dictionary_name,
     const lldb::StackFrameSP &sb_frame,
-    const lldb::BreakpointLocationSP &sb_bp_loc);
+    const lldb::BreakpointLocationSP &sb_bp_loc, StructuredDataImpl *args_impl);
+
+#if _MSC_VER
+#pragma warning (pop)
+#endif
+
+#pragma clang diagnostic pop
 
 extern "C" bool LLDBSwigPythonWatchpointCallbackFunction(
     const char *python_function_name, const char *session_dictionary_name,
@@ -211,6 +228,22 @@ public:
 
     InitializePythonHome();
 
+#ifdef LLDB_USE_LIBEDIT_READLINE_COMPAT_MODULE
+    // Python's readline is incompatible with libedit being linked into lldb.
+    // Provide a patched version local to the embedded interpreter.
+    bool ReadlinePatched = false;
+    for (auto *p = PyImport_Inittab; p->name != NULL; p++) {
+      if (strcmp(p->name, "readline") == 0) {
+        p->initfunc = initlldb_readline;
+        break;
+      }
+    }
+    if (!ReadlinePatched) {
+      PyImport_AppendInittab("readline", initlldb_readline);
+      ReadlinePatched = true;
+    }
+#endif
+
     // Register _lldb as a built-in module.
     PyImport_AppendInittab("_lldb", LLDBSwigPyInit);
 
@@ -552,8 +585,10 @@ void ScriptInterpreterPythonImpl::IOHandlerInputComplete(IOHandler &io_handler,
         break;
       data_up->user_source.SplitIntoLines(data);
 
+      StructuredData::ObjectSP empty_args_sp;
       if (GenerateBreakpointCommandCallbackData(data_up->user_source,
-                                                data_up->script_source)
+                                                data_up->script_source,
+                                                false)
               .Success()) {
         auto baton_sp = std::make_shared<BreakpointOptions::CommandBaton>(
             std::move(data_up));
@@ -779,6 +814,32 @@ PythonDictionary &ScriptInterpreterPythonImpl::GetSysModuleDictionary() {
   return m_sys_module_dict;
 }
 
+llvm::Expected<unsigned>
+ScriptInterpreterPythonImpl::GetMaxPositionalArgumentsForCallable(
+    const llvm::StringRef &callable_name) {
+  if (callable_name.empty()) {
+    return llvm::createStringError(
+        llvm::inconvertibleErrorCode(),
+        "called with empty callable name.");
+  }
+  Locker py_lock(this, Locker::AcquireLock |
+                 Locker::InitSession |
+                 Locker::NoSTDIN);
+  auto dict = PythonModule::MainModule()
+      .ResolveName<PythonDictionary>(m_dictionary_name);
+  auto pfunc = PythonObject::ResolveNameWithDictionary<PythonCallable>(
+      callable_name, dict);
+  if (!pfunc.IsAllocated()) {
+    return llvm::createStringError(
+        llvm::inconvertibleErrorCode(),
+        "can't find callable: %s", callable_name.str().c_str());
+  }
+  llvm::Expected<PythonCallable::ArgInfo> arg_info = pfunc.GetArgInfo();
+  if (!arg_info)
+    return arg_info.takeError();
+  return arg_info.get().max_positional_args;
+}
+
 static std::string GenerateUniqueName(const char *base_name_wanted,
                                       uint32_t &functions_counter,
                                       const void *name_token = nullptr) {
@@ -1139,6 +1200,7 @@ bool ScriptInterpreterPythonImpl::ExecuteOneLineWithReturn(
     return true;
   }
   }
+  llvm_unreachable("Fully covered switch!");
 }
 
 Status ScriptInterpreterPythonImpl::ExecuteMultipleLines(
@@ -1186,24 +1248,56 @@ void ScriptInterpreterPythonImpl::CollectDataForBreakpointCommandCallback(
     CommandReturnObject &result) {
   m_active_io_handler = eIOHandlerBreakpoint;
   m_debugger.GetCommandInterpreter().GetPythonCommandsFromIOHandler(
-      "    ", *this, true, &bp_options_vec);
+      "    ", *this, &bp_options_vec);
 }
 
 void ScriptInterpreterPythonImpl::CollectDataForWatchpointCommandCallback(
     WatchpointOptions *wp_options, CommandReturnObject &result) {
   m_active_io_handler = eIOHandlerWatchpoint;
   m_debugger.GetCommandInterpreter().GetPythonCommandsFromIOHandler(
-      "    ", *this, true, wp_options);
+      "    ", *this, wp_options);
 }
 
-void ScriptInterpreterPythonImpl::SetBreakpointCommandCallbackFunction(
-    BreakpointOptions *bp_options, const char *function_name) {
+Status ScriptInterpreterPythonImpl::SetBreakpointCommandCallbackFunction(
+    BreakpointOptions *bp_options, const char *function_name,
+    StructuredData::ObjectSP extra_args_sp) {
+  Status error;
   // For now just cons up a oneliner that calls the provided function.
   std::string oneliner("return ");
   oneliner += function_name;
-  oneliner += "(frame, bp_loc, internal_dict)";
-  m_debugger.GetScriptInterpreter()->SetBreakpointCommandCallback(
-      bp_options, oneliner.c_str());
+
+  llvm::Expected<unsigned> maybe_args =
+      GetMaxPositionalArgumentsForCallable(function_name);
+  if (!maybe_args) {
+    error.SetErrorStringWithFormat(
+        "could not get num args: %s",
+        llvm::toString(maybe_args.takeError()).c_str());
+    return error;
+  }
+  size_t max_args = *maybe_args;
+
+  bool uses_extra_args = false;
+  if (max_args >= 4) {
+    uses_extra_args = true;
+    oneliner += "(frame, bp_loc, extra_args, internal_dict)";
+  } else if (max_args >= 3) {
+    if (extra_args_sp) {
+      error.SetErrorString("cannot pass extra_args to a three argument callback"
+                          );
+      return error;
+    }
+    uses_extra_args = false;
+    oneliner += "(frame, bp_loc, internal_dict)";
+  } else {
+    error.SetErrorStringWithFormat("expected 3 or 4 argument "
+                                   "function, %s can only take %zu",
+                                   function_name, max_args);
+    return error;
+  }
+
+  SetBreakpointCommandCallback(bp_options, oneliner.c_str(), extra_args_sp,
+                               uses_extra_args);
+  return error;
 }
 
 Status ScriptInterpreterPythonImpl::SetBreakpointCommandCallback(
@@ -1211,7 +1305,8 @@ Status ScriptInterpreterPythonImpl::SetBreakpointCommandCallback(
     std::unique_ptr<BreakpointOptions::CommandData> &cmd_data_up) {
   Status error;
   error = GenerateBreakpointCommandCallbackData(cmd_data_up->user_source,
-                                                cmd_data_up->script_source);
+                                                cmd_data_up->script_source,
+                                                false);
   if (error.Fail()) {
     return error;
   }
@@ -1222,11 +1317,17 @@ Status ScriptInterpreterPythonImpl::SetBreakpointCommandCallback(
   return error;
 }
 
-// Set a Python one-liner as the callback for the breakpoint.
 Status ScriptInterpreterPythonImpl::SetBreakpointCommandCallback(
     BreakpointOptions *bp_options, const char *command_body_text) {
-  auto data_up = std::make_unique<CommandDataPython>();
+  return SetBreakpointCommandCallback(bp_options, command_body_text, {},false);
+}
 
+// Set a Python one-liner as the callback for the breakpoint.
+Status ScriptInterpreterPythonImpl::SetBreakpointCommandCallback(
+    BreakpointOptions *bp_options, const char *command_body_text,
+    StructuredData::ObjectSP extra_args_sp,
+    bool uses_extra_args) {
+  auto data_up = std::make_unique<CommandDataPython>(extra_args_sp);
   // Split the command_body_text into lines, and pass that to
   // GenerateBreakpointCommandCallbackData.  That will wrap the body in an
   // auto-generated function, and return the function name in script_source.
@@ -1234,7 +1335,8 @@ Status ScriptInterpreterPythonImpl::SetBreakpointCommandCallback(
 
   data_up->user_source.SplitIntoLines(command_body_text);
   Status error = GenerateBreakpointCommandCallbackData(data_up->user_source,
-                                                       data_up->script_source);
+                                                       data_up->script_source,
+                                                       uses_extra_args);
   if (error.Success()) {
     auto baton_sp =
         std::make_shared<BreakpointOptions::CommandBaton>(std::move(data_up));
@@ -1771,8 +1873,7 @@ StructuredData::DictionarySP ScriptInterpreterPythonImpl::OSPlugin_CreateThread(
 
 StructuredData::ObjectSP ScriptInterpreterPythonImpl::CreateScriptedThreadPlan(
     const char *class_name, StructuredDataImpl *args_data,
-    std::string &error_str, 
-    lldb::ThreadPlanSP thread_plan_sp) {
+    std::string &error_str, lldb::ThreadPlanSP thread_plan_sp) {
   if (class_name == nullptr || class_name[0] == '\0')
     return StructuredData::ObjectSP();
 
@@ -1956,8 +2057,7 @@ ScriptInterpreterPythonImpl::LoadPluginModule(const FileSpec &file_spec,
 
   StructuredData::ObjectSP module_sp;
 
-  if (LoadScriptingModule(file_spec.GetPath().c_str(), true, true, error,
-                          &module_sp))
+  if (LoadScriptingModule(file_spec.GetPath().c_str(), true, error, &module_sp))
     return module_sp;
 
   return StructuredData::ObjectSP();
@@ -2063,7 +2163,8 @@ bool ScriptInterpreterPythonImpl::GenerateTypeSynthClass(
 }
 
 Status ScriptInterpreterPythonImpl::GenerateBreakpointCommandCallbackData(
-    StringList &user_input, std::string &output) {
+    StringList &user_input, std::string &output,
+    bool has_extra_args) {
   static uint32_t num_created_functions = 0;
   user_input.RemoveBlankLines();
   StreamString sstr;
@@ -2075,8 +2176,12 @@ Status ScriptInterpreterPythonImpl::GenerateBreakpointCommandCallbackData(
 
   std::string auto_generated_function_name(GenerateUniqueName(
       "lldb_autogen_python_bp_callback_func_", num_created_functions));
-  sstr.Printf("def %s (frame, bp_loc, internal_dict):",
-              auto_generated_function_name.c_str());
+  if (has_extra_args)
+    sstr.Printf("def %s (frame, bp_loc, extra_args, internal_dict):",
+                auto_generated_function_name.c_str());
+  else
+    sstr.Printf("def %s (frame, bp_loc, internal_dict):",
+                auto_generated_function_name.c_str());
 
   error = GenerateFunction(sstr.GetData(), user_input);
   if (!error.Success())
@@ -2193,10 +2298,26 @@ bool ScriptInterpreterPythonImpl::BreakpointCallbackFunction(
           Locker py_lock(python_interpreter, Locker::AcquireLock |
                                                  Locker::InitSession |
                                                  Locker::NoSTDIN);
-          ret_val = LLDBSwigPythonBreakpointCallbackFunction(
-              python_function_name,
-              python_interpreter->m_dictionary_name.c_str(), stop_frame_sp,
-              bp_loc_sp);
+          Expected<bool> maybe_ret_val =
+              LLDBSwigPythonBreakpointCallbackFunction(
+                  python_function_name,
+                  python_interpreter->m_dictionary_name.c_str(), stop_frame_sp,
+                  bp_loc_sp, bp_option_data->m_extra_args_up.get());
+
+          if (!maybe_ret_val) {
+
+            llvm::handleAllErrors(
+                maybe_ret_val.takeError(),
+                [&](PythonException &E) {
+                  debugger.GetErrorStream() << E.ReadBacktrace();
+                },
+                [&](const llvm::ErrorInfoBase &E) {
+                  debugger.GetErrorStream() << E.message();
+                });
+
+          } else {
+            ret_val = maybe_ret_val.get();
+          }
         }
         return ret_val;
       }
@@ -2615,8 +2736,8 @@ uint64_t replace_all(std::string &str, const std::string &oldStr,
 }
 
 bool ScriptInterpreterPythonImpl::LoadScriptingModule(
-    const char *pathname, bool can_reload, bool init_session,
-    lldb_private::Status &error, StructuredData::ObjectSP *module_sp) {
+    const char *pathname, bool init_session, lldb_private::Status &error,
+    StructuredData::ObjectSP *module_sp) {
   if (!pathname || !pathname[0]) {
     error.SetErrorString("invalid pathname");
     return false;
@@ -2716,11 +2837,6 @@ bool ScriptInterpreterPythonImpl::LoadScriptingModule(
 
     bool was_imported = (was_imported_globally || was_imported_locally);
 
-    if (was_imported && !can_reload) {
-      error.SetErrorString("module already imported");
-      return false;
-    }
-
     // now actually do the import
     command_stream.Clear();
 
@@ -3171,4 +3287,4 @@ void ScriptInterpreterPythonImpl::AddToSysPath(AddLocation location,
 //
 // void ScriptInterpreterPythonImpl::Terminate() { Py_Finalize (); }
 
-#endif // LLDB_DISABLE_PYTHON
+#endif
diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.h b/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.h
index 33ae308041b2..e59fedbd0971 100644
--- a/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.h
+++ b/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.h
@@ -9,14 +9,13 @@
 #ifndef LLDB_PLUGINS_SCRIPTINTERPRETER_PYTHON_SCRIPTINTERPRETERPYTHON_H
 #define LLDB_PLUGINS_SCRIPTINTERPRETER_PYTHON_SCRIPTINTERPRETERPYTHON_H
 
-#ifdef LLDB_DISABLE_PYTHON
+#include "lldb/Host/Config.h"
 
-// Python is disabled in this build
-
-#else
+#if LLDB_ENABLE_PYTHON
 
 #include "lldb/Breakpoint/BreakpointOptions.h"
 #include "lldb/Core/IOHandler.h"
+#include "lldb/Core/StructuredDataImpl.h"
 #include "lldb/Interpreter/ScriptInterpreter.h"
 #include "lldb/lldb-private.h"
 
@@ -34,6 +33,13 @@ public:
     CommandDataPython() : BreakpointOptions::CommandData() {
       interpreter = lldb::eScriptLanguagePython;
     }
+    CommandDataPython(StructuredData::ObjectSP extra_args_sp) :
+        BreakpointOptions::CommandData(),
+        m_extra_args_up(new StructuredDataImpl()) {
+        interpreter = lldb::eScriptLanguagePython;
+        m_extra_args_up->SetObjectSP(extra_args_sp);
+    }
+    lldb::StructuredDataImplUP m_extra_args_up;
   };
 
   ScriptInterpreterPython(Debugger &debugger)
@@ -52,5 +58,5 @@ protected:
 };
 } // namespace lldb_private
 
-#endif // LLDB_DISABLE_PYTHON
+#endif // LLDB_ENABLE_PYTHON
 #endif // LLDB_PLUGINS_SCRIPTINTERPRETER_PYTHON_SCRIPTINTERPRETERPYTHON_H
diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPythonImpl.h b/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPythonImpl.h
index 929567e579d8..1fa198b07e54 100644
--- a/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPythonImpl.h
+++ b/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPythonImpl.h
@@ -6,11 +6,9 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifdef LLDB_DISABLE_PYTHON
+#include "lldb/Host/Config.h"
 
-// Python is disabled in this build
-
-#else
+#if LLDB_ENABLE_PYTHON
 
 #include "lldb-python.h"
 
@@ -179,8 +177,10 @@ public:
   Status GenerateFunction(const char *signature,
                           const StringList &input) override;
 
-  Status GenerateBreakpointCommandCallbackData(StringList &input,
-                                               std::string &output) override;
+  Status GenerateBreakpointCommandCallbackData(
+      StringList &input,
+      std::string &output,
+      bool has_extra_args) override;
 
   bool GenerateWatchpointCommandCallbackData(StringList &input,
                                              std::string &output) override;
@@ -224,7 +224,7 @@ public:
                               std::string &output, Status &error) override;
 
   bool
-  LoadScriptingModule(const char *filename, bool can_reload, bool init_session,
+  LoadScriptingModule(const char *filename, bool init_session,
                       lldb_private::Status &error,
                       StructuredData::ObjectSP *module_sp = nullptr) override;
 
@@ -244,14 +244,21 @@ public:
   Status SetBreakpointCommandCallback(BreakpointOptions *bp_options,
                                       const char *callback_body) override;
 
-  void SetBreakpointCommandCallbackFunction(BreakpointOptions *bp_options,
-                                            const char *function_name) override;
+  Status SetBreakpointCommandCallbackFunction(
+      BreakpointOptions *bp_options,
+      const char *function_name,
+      StructuredData::ObjectSP extra_args_sp) override;
 
   /// This one is for deserialization:
   Status SetBreakpointCommandCallback(
       BreakpointOptions *bp_options,
       std::unique_ptr<BreakpointOptions::CommandData> &data_up) override;
 
+  Status SetBreakpointCommandCallback(BreakpointOptions *bp_options,
+                                      const char *command_body_text,
+                                      StructuredData::ObjectSP extra_args_sp,
+                                      bool uses_extra_args);
+
   /// Set a one-liner as the callback for the watchpoint.
   void SetWatchpointCommandCallback(WatchpointOptions *wp_options,
                                     const char *oneliner) override;
@@ -369,6 +376,9 @@ public:
 
   python::PythonDictionary &GetSysModuleDictionary();
 
+  llvm::Expected<unsigned> GetMaxPositionalArgumentsForCallable(
+      const llvm::StringRef &callable_name) override;
+
   bool GetEmbeddedInterpreterModuleObjects();
 
   bool SetStdHandle(lldb::FileSP file, const char *py_name,
diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/lldb-python.h b/lldb/source/Plugins/ScriptInterpreter/Python/lldb-python.h
index 884514da9924..48f27b09b95c 100644
--- a/lldb/source/Plugins/ScriptInterpreter/Python/lldb-python.h
+++ b/lldb/source/Plugins/ScriptInterpreter/Python/lldb-python.h
@@ -9,12 +9,12 @@
 #ifndef LLDB_PLUGINS_SCRIPTINTERPRETER_PYTHON_LLDB_PYTHON_H
 #define LLDB_PLUGINS_SCRIPTINTERPRETER_PYTHON_LLDB_PYTHON_H
 
+#include "lldb/Host/Config.h"
+
 // Python.h needs to be included before any system headers in order to avoid
 // redefinition of macros
 
-#ifdef LLDB_DISABLE_PYTHON
-// Python is disabled in this build
-#else
+#if LLDB_ENABLE_PYTHON
 #include "llvm/Support/Compiler.h"
 #if defined(_WIN32)
 // If anyone #includes Host/PosixApi.h later, it will try to typedef pid_t.  We
@@ -40,6 +40,6 @@
 
 // Include python for non windows machines
 #include <Python.h>
-#endif // LLDB_DISABLE_PYTHON
+#endif
 
 #endif // LLDB_PLUGINS_SCRIPTINTERPRETER_PYTHON_LLDB_PYTHON_H
diff --git a/lldb/source/Plugins/SymbolFile/Breakpad/SymbolFileBreakpad.cpp b/lldb/source/Plugins/SymbolFile/Breakpad/SymbolFileBreakpad.cpp
index f84cf0c5368d..b2c4d0883341 100644
--- a/lldb/source/Plugins/SymbolFile/Breakpad/SymbolFileBreakpad.cpp
+++ b/lldb/source/Plugins/SymbolFile/Breakpad/SymbolFileBreakpad.cpp
@@ -25,6 +25,8 @@ using namespace lldb;
 using namespace lldb_private;
 using namespace lldb_private::breakpad;
 
+char SymbolFileBreakpad::ID;
+
 class SymbolFileBreakpad::LineIterator {
 public:
   // begin iterator for sections of given type
@@ -307,8 +309,9 @@ void SymbolFileBreakpad::FindTypes(
     uint32_t max_matches, llvm::DenseSet<SymbolFile *> &searched_symbol_files,
     TypeMap &types) {}
 
-void SymbolFileBreakpad::FindTypes(llvm::ArrayRef<CompilerContext> pattern,
-                                   LanguageSet languages, TypeMap &types) {}
+void SymbolFileBreakpad::FindTypes(
+    llvm::ArrayRef<CompilerContext> pattern, LanguageSet languages,
+    llvm::DenseSet<SymbolFile *> &searched_symbol_files, TypeMap &types) {}
 
 void SymbolFileBreakpad::AddSymbols(Symtab &symtab) {
   Log *log = GetLogIfAllCategoriesSet(LIBLLDB_LOG_SYMBOLS);
@@ -728,7 +731,7 @@ void SymbolFileBreakpad::ParseLineTableAndSupportFiles(CompileUnit &cu,
   }
   if (next_addr)
     finish_sequence();
-  data.support_files = map.translate(cu, *m_files);
+  data.support_files = map.translate(cu.GetPrimaryFile(), *m_files);
 }
 
 void SymbolFileBreakpad::ParseUnwindData() {
diff --git a/lldb/source/Plugins/SymbolFile/Breakpad/SymbolFileBreakpad.h b/lldb/source/Plugins/SymbolFile/Breakpad/SymbolFileBreakpad.h
index a10138cdf92f..de271224a65d 100644
--- a/lldb/source/Plugins/SymbolFile/Breakpad/SymbolFileBreakpad.h
+++ b/lldb/source/Plugins/SymbolFile/Breakpad/SymbolFileBreakpad.h
@@ -21,7 +21,18 @@ namespace lldb_private {
 namespace breakpad {
 
 class SymbolFileBreakpad : public SymbolFile {
+  /// LLVM RTTI support.
+  static char ID;
+
 public:
+  /// LLVM RTTI support.
+  /// \{
+  bool isA(const void *ClassID) const override {
+    return ClassID == &ID || SymbolFile::isA(ClassID);
+  }
+  static bool classof(const SymbolFile *obj) { return obj->isA(&ID); }
+  /// \}
+
   // Static Functions
   static void Initialize();
   static void Terminate();
@@ -112,6 +123,7 @@ public:
                  TypeMap &types) override;
 
   void FindTypes(llvm::ArrayRef<CompilerContext> pattern, LanguageSet languages,
+                 llvm::DenseSet<SymbolFile *> &searched_symbol_files,
                  TypeMap &types) override;
 
   llvm::Expected<TypeSystem &>
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp b/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp
index 636e6032b877..232063a6f339 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp
@@ -22,7 +22,7 @@
 #include "lldb/Core/Value.h"
 #include "lldb/Host/Host.h"
 #include "lldb/Symbol/ClangASTImporter.h"
-#include "lldb/Symbol/ClangExternalASTSourceCommon.h"
+#include "lldb/Symbol/ClangASTMetadata.h"
 #include "lldb/Symbol/ClangUtil.h"
 #include "lldb/Symbol/CompileUnit.h"
 #include "lldb/Symbol/Function.h"
@@ -135,61 +135,111 @@ static bool IsClangModuleFwdDecl(const DWARFDIE &Die) {
   return false;
 }
 
-TypeSP DWARFASTParserClang::ParseTypeFromDWO(const DWARFDIE &die, Log *log) {
-  ModuleSP dwo_module_sp = die.GetContainingDWOModule();
-  if (!dwo_module_sp)
+static DWARFDIE GetContainingClangModuleDIE(const DWARFDIE &die) {
+  if (die.IsValid()) {
+    DWARFDIE top_module_die;
+    // Now make sure this DIE is scoped in a DW_TAG_module tag and return true
+    // if so
+    for (DWARFDIE parent = die.GetParent(); parent.IsValid();
+         parent = parent.GetParent()) {
+      const dw_tag_t tag = parent.Tag();
+      if (tag == DW_TAG_module)
+        top_module_die = parent;
+      else if (tag == DW_TAG_compile_unit || tag == DW_TAG_partial_unit)
+        break;
+    }
+
+    return top_module_die;
+  }
+  return DWARFDIE();
+}
+
+static lldb::ModuleSP GetContainingClangModule(const DWARFDIE &die) {
+  if (die.IsValid()) {
+    DWARFDIE clang_module_die = GetContainingClangModuleDIE(die);
+
+    if (clang_module_die) {
+      const char *module_name = clang_module_die.GetName();
+      if (module_name)
+        return die.GetDWARF()->GetExternalModule(
+            lldb_private::ConstString(module_name));
+    }
+  }
+  return lldb::ModuleSP();
+}
+
+TypeSP DWARFASTParserClang::ParseTypeFromClangModule(const SymbolContext &sc,
+                                                     const DWARFDIE &die,
+                                                     Log *log) {
+  ModuleSP clang_module_sp = GetContainingClangModule(die);
+  if (!clang_module_sp)
     return TypeSP();
 
-  // If this type comes from a Clang module, look in the DWARF section
-  // of the pcm file in the module cache. Clang generates DWO skeleton
-  // units as breadcrumbs to find them.
+  // If this type comes from a Clang module, recursively look in the
+  // DWARF section of the .pcm file in the module cache. Clang
+  // generates DWO skeleton units as breadcrumbs to find them.
   llvm::SmallVector<CompilerContext, 4> decl_context;
   die.GetDeclContext(decl_context);
-  TypeMap dwo_types;
+  TypeMap pcm_types;
 
   // The type in the Clang module must have the same language as the current CU.
   LanguageSet languages;
   languages.Insert(die.GetCU()->GetLanguageType());
-  dwo_module_sp->GetSymbolFile()->FindTypes(decl_context, languages, dwo_types);
-  if (dwo_types.Empty()) {
-    if (!IsClangModuleFwdDecl(die))
-      return TypeSP();
-
+  llvm::DenseSet<SymbolFile *> searched_symbol_files;
+  clang_module_sp->GetSymbolFile()->FindTypes(decl_context, languages,
+                                              searched_symbol_files, pcm_types);
+  if (pcm_types.Empty()) {
     // Since this type is defined in one of the Clang modules imported
-    // by this symbol file, search all of them.
+    // by this symbol file, search all of them. Instead of calling
+    // sym_file->FindTypes(), which would return this again, go straight
+    // to the imported modules.
     auto &sym_file = die.GetCU()->GetSymbolFileDWARF();
-    for (const auto &name_module : sym_file.getExternalTypeModules()) {
-      if (!name_module.second)
-        continue;
-      name_module.second->GetSymbolFile()->FindTypes(decl_context,
-                                                     languages, dwo_types);
-      if (dwo_types.GetSize())
-        break;
-    }
+
+    // Well-formed clang modules never form cycles; guard against corrupted
+    // ones by inserting the current file.
+    searched_symbol_files.insert(&sym_file);
+    sym_file.ForEachExternalModule(
+        *sc.comp_unit, searched_symbol_files, [&](Module &module) {
+          module.GetSymbolFile()->FindTypes(decl_context, languages,
+                                            searched_symbol_files, pcm_types);
+          return pcm_types.GetSize();
+        });
   }
 
-  if (dwo_types.GetSize() != 1)
+  if (!pcm_types.GetSize())
     return TypeSP();
 
   // We found a real definition for this type in the Clang module, so lets use
   // it and cache the fact that we found a complete type for this die.
-  TypeSP dwo_type_sp = dwo_types.GetTypeAtIndex(0);
-  if (!dwo_type_sp)
+  TypeSP pcm_type_sp = pcm_types.GetTypeAtIndex(0);
+  if (!pcm_type_sp)
     return TypeSP();
 
-  lldb_private::CompilerType dwo_type = dwo_type_sp->GetForwardCompilerType();
-
+  lldb_private::CompilerType pcm_type = pcm_type_sp->GetForwardCompilerType();
   lldb_private::CompilerType type =
-      GetClangASTImporter().CopyType(m_ast, dwo_type);
+      GetClangASTImporter().CopyType(m_ast, pcm_type);
 
   if (!type)
     return TypeSP();
 
+  // Under normal operation pcm_type is a shallow forward declaration
+  // that gets completed later. This is necessary to support cyclic
+  // data structures. If, however, pcm_type is already complete (for
+  // example, because it was loaded for a different target before),
+  // the definition needs to be imported right away, too.
+  // Type::ResolveClangType() effectively ignores the ResolveState
+  // inside type_sp and only looks at IsDefined(), so it never calls
+  // ClangASTImporter::ASTImporterDelegate::ImportDefinitionTo(),
+  // which does extra work for Objective-C classes. This would result
+  // in only the forward declaration to be visible.
+  if (pcm_type.IsDefined())
+    GetClangASTImporter().RequireCompleteType(ClangUtil::GetQualType(type));
+
   SymbolFileDWARF *dwarf = die.GetDWARF();
   TypeSP type_sp(new Type(
-      die.GetID(), dwarf, dwo_type_sp->GetName(), dwo_type_sp->GetByteSize(),
+      die.GetID(), dwarf, pcm_type_sp->GetName(), pcm_type_sp->GetByteSize(),
       nullptr, LLDB_INVALID_UID, Type::eEncodingInvalid,
-      &dwo_type_sp->GetDeclaration(), type, Type::eResolveStateForward));
+      &pcm_type_sp->GetDeclaration(), type, Type::ResolveState::Forward));
 
   dwarf->GetTypeList().Insert(type_sp);
   dwarf->GetDIEToType()[die.GetDIE()] = type_sp.get();
@@ -205,7 +255,8 @@ TypeSP DWARFASTParserClang::ParseTypeFromDWO(const DWARFDIE &die, Log *log) {
   return type_sp;
 }
 
-static void CompleteExternalTagDeclType(ClangASTImporter &ast_importer,
+static void CompleteExternalTagDeclType(ClangASTContext &ast,
+                                        ClangASTImporter &ast_importer,
                                         clang::DeclContext *decl_ctx,
                                         DWARFDIE die,
                                         const char *type_name_cstr) {
@@ -214,7 +265,7 @@ static void CompleteExternalTagDeclType(ClangASTImporter &ast_importer,
     return;
 
   // If this type was not imported from an external AST, there's nothing to do.
-  CompilerType type = ClangASTContext::GetTypeForDecl(tag_decl_ctx);
+  CompilerType type = ast.GetTypeForDecl(tag_decl_ctx);
   if (!type || !ast_importer.CanImport(type))
     return;
 
@@ -340,6 +391,10 @@ ParsedDWARFTypeAttributes::ParsedDWARFTypeAttributes(const DWARFDIE &die) {
       is_complete_objc_class = form_value.Signed();
       break;
 
+    case DW_AT_APPLE_objc_direct:
+      is_objc_direct_call = true;
+      break;
+
     case DW_AT_APPLE_runtime_class:
       class_language = (LanguageType)form_value.Signed();
       break;
@@ -347,6 +402,9 @@ ParsedDWARFTypeAttributes::ParsedDWARFTypeAttributes(const DWARFDIE &die) {
     case DW_AT_GNU_vector:
       is_vector = form_value.Boolean();
       break;
+    case DW_AT_export_symbols:
+      exports_symbols = form_value.Boolean();
+      break;
     }
   }
 }
@@ -377,13 +435,12 @@ TypeSP DWARFASTParserClang::ParseTypeFromDWARF(const SymbolContext &sc,
 
     dwarf->GetObjectFile()->GetModule()->LogMessage(
         log,
-        "SymbolFileDWARF::ParseType (die = 0x%8.8x, decl_ctx = %p (die "
-        "0x%8.8x)) %s name = '%s')",
+        "DWARFASTParserClang::ParseTypeFromDWARF "
+        "(die = 0x%8.8x, decl_ctx = %p (die 0x%8.8x)) %s name = '%s')",
         die.GetOffset(), static_cast<void *>(context), context_die.GetOffset(),
         die.GetTagAsCString(), die.GetName());
   }
 
-
   Type *type_ptr = dwarf->GetDIEToType().lookup(die.GetDIE());
   if (type_ptr == DIE_IS_BEING_PARSED)
     return nullptr;
@@ -411,13 +468,8 @@ TypeSP DWARFASTParserClang::ParseTypeFromDWARF(const SymbolContext &sc,
 
   const dw_tag_t tag = die.Tag();
 
-  Type::ResolveState resolve_state = Type::eResolveStateUnresolved;
-
-  Type::EncodingDataType encoding_data_type = Type::eEncodingIsUID;
-  CompilerType clang_type;
-
   TypeSP type_sp;
-  LanguageType cu_language = die.GetLanguage();
+
   switch (tag) {
   case DW_TAG_typedef:
   case DW_TAG_base_type:
@@ -427,848 +479,895 @@ TypeSP DWARFASTParserClang::ParseTypeFromDWARF(const SymbolContext &sc,
   case DW_TAG_const_type:
   case DW_TAG_restrict_type:
   case DW_TAG_volatile_type:
+  case DW_TAG_atomic_type:
   case DW_TAG_unspecified_type: {
-    if (tag == DW_TAG_typedef && attrs.type.IsValid()) {
-      // Try to parse a typedef from the DWO file first as modules can
-      // contain typedef'ed structures that have no names like:
-      //
-      //  typedef struct { int a; } Foo;
-      //
-      // In this case we will have a structure with no name and a typedef
-      // named "Foo" that points to this unnamed structure. The name in the
-      // typedef is the only identifier for the struct, so always try to
-      // get typedefs from DWO files if possible.
-      //
-      // The type_sp returned will be empty if the typedef doesn't exist in
-      // a DWO file, so it is cheap to call this function just to check.
-      //
-      // If we don't do this we end up creating a TypeSP that says this is
-      // a typedef to type 0x123 (the DW_AT_type value would be 0x123 in
-      // the DW_TAG_typedef), and this is the unnamed structure type. We
-      // will have a hard time tracking down an unnammed structure type in
-      // the module DWO file, so we make sure we don't get into this
-      // situation by always resolving typedefs from the DWO file.
-      const DWARFDIE encoding_die = attrs.type.Reference();
-
-      // First make sure that the die that this is typedef'ed to _is_ just
-      // a declaration (DW_AT_declaration == 1), not a full definition
-      // since template types can't be represented in modules since only
-      // concrete instances of templates are ever emitted and modules won't
-      // contain those
-      if (encoding_die &&
-          encoding_die.GetAttributeValueAsUnsigned(DW_AT_declaration, 0) == 1) {
-        type_sp = ParseTypeFromDWO(die, log);
-        if (type_sp)
-          return type_sp;
-      }
-    }
+    type_sp = ParseTypeModifier(sc, die, attrs);
+    break;
+  }
 
-    DEBUG_PRINTF("0x%8.8" PRIx64 ": %s (\"%s\") type => 0x%8.8lx\n",
-                 die.GetID(), DW_TAG_value_to_name(tag), type_name_cstr,
-                 encoding_uid.Reference());
+  case DW_TAG_structure_type:
+  case DW_TAG_union_type:
+  case DW_TAG_class_type: {
+    type_sp = ParseStructureLikeDIE(sc, die, attrs);
+    break;
+  }
 
-    switch (tag) {
-    default:
-      break;
+  case DW_TAG_enumeration_type: {
+    type_sp = ParseEnum(sc, die, attrs);
+    break;
+  }
 
-    case DW_TAG_unspecified_type:
-      if (attrs.name == "nullptr_t" || attrs.name == "decltype(nullptr)") {
-        resolve_state = Type::eResolveStateFull;
-        clang_type = m_ast.GetBasicType(eBasicTypeNullPtr);
-        break;
-      }
-      // Fall through to base type below in case we can handle the type
-      // there...
-      LLVM_FALLTHROUGH;
-
-    case DW_TAG_base_type:
-      resolve_state = Type::eResolveStateFull;
-      clang_type = m_ast.GetBuiltinTypeForDWARFEncodingAndBitSize(
-          attrs.name.GetCString(), attrs.encoding,
-          attrs.byte_size.getValueOr(0) * 8);
-      break;
+  case DW_TAG_inlined_subroutine:
+  case DW_TAG_subprogram:
+  case DW_TAG_subroutine_type: {
+    type_sp = ParseSubroutine(die, attrs);
+    break;
+  }
+  case DW_TAG_array_type: {
+    type_sp = ParseArrayType(die, attrs);
+    break;
+  }
+  case DW_TAG_ptr_to_member_type: {
+    type_sp = ParsePointerToMemberType(die, attrs);
+    break;
+  }
+  default:
+    dwarf->GetObjectFile()->GetModule()->ReportError(
+        "{0x%8.8x}: unhandled type tag 0x%4.4x (%s), please file a bug and "
+        "attach the file at the start of this error message",
+        die.GetOffset(), tag, DW_TAG_value_to_name(tag));
+    break;
+  }
 
-    case DW_TAG_pointer_type:
-      encoding_data_type = Type::eEncodingIsPointerUID;
-      break;
-    case DW_TAG_reference_type:
-      encoding_data_type = Type::eEncodingIsLValueReferenceUID;
-      break;
-    case DW_TAG_rvalue_reference_type:
-      encoding_data_type = Type::eEncodingIsRValueReferenceUID;
-      break;
-    case DW_TAG_typedef:
-      encoding_data_type = Type::eEncodingIsTypedefUID;
-      break;
-    case DW_TAG_const_type:
-      encoding_data_type = Type::eEncodingIsConstUID;
-      break;
-    case DW_TAG_restrict_type:
-      encoding_data_type = Type::eEncodingIsRestrictUID;
-      break;
-    case DW_TAG_volatile_type:
-      encoding_data_type = Type::eEncodingIsVolatileUID;
+  // TODO: We should consider making the switch above exhaustive to simplify
+  // control flow in ParseTypeFromDWARF. Then, we could simply replace this
+  // return statement with a call to llvm_unreachable.
+  return UpdateSymbolContextScopeForType(sc, die, type_sp);
+}
+
+lldb::TypeSP
+DWARFASTParserClang::ParseTypeModifier(const SymbolContext &sc,
+                                       const DWARFDIE &die,
+                                       ParsedDWARFTypeAttributes &attrs) {
+  Log *log(LogChannelDWARF::GetLogIfAny(DWARF_LOG_TYPE_COMPLETION |
+                                        DWARF_LOG_LOOKUPS));
+  SymbolFileDWARF *dwarf = die.GetDWARF();
+  const dw_tag_t tag = die.Tag();
+  LanguageType cu_language = die.GetLanguage();
+  Type::ResolveState resolve_state = Type::ResolveState::Unresolved;
+  Type::EncodingDataType encoding_data_type = Type::eEncodingIsUID;
+  TypeSP type_sp;
+  CompilerType clang_type;
+
+  if (tag == DW_TAG_typedef && attrs.type.IsValid()) {
+    // Try to parse a typedef from the (DWARF embedded in the) Clang
+    // module file first as modules can contain typedef'ed
+    // structures that have no names like:
+    //
+    //  typedef struct { int a; } Foo;
+    //
+    // In this case we will have a structure with no name and a
+    // typedef named "Foo" that points to this unnamed
+    // structure. The name in the typedef is the only identifier for
+    // the struct, so always try to get typedefs from Clang modules
+    // if possible.
+    //
+    // The type_sp returned will be empty if the typedef doesn't
+    // exist in a module file, so it is cheap to call this function
+    // just to check.
+    //
+    // If we don't do this we end up creating a TypeSP that says
+    // this is a typedef to type 0x123 (the DW_AT_type value would
+    // be 0x123 in the DW_TAG_typedef), and this is the unnamed
+    // structure type. We will have a hard time tracking down an
+    // unnammed structure type in the module debug info, so we make
+    // sure we don't get into this situation by always resolving
+    // typedefs from the module.
+    const DWARFDIE encoding_die = attrs.type.Reference();
+
+    // First make sure that the die that this is typedef'ed to _is_
+    // just a declaration (DW_AT_declaration == 1), not a full
+    // definition since template types can't be represented in
+    // modules since only concrete instances of templates are ever
+    // emitted and modules won't contain those
+    if (encoding_die &&
+        encoding_die.GetAttributeValueAsUnsigned(DW_AT_declaration, 0) == 1) {
+      type_sp = ParseTypeFromClangModule(sc, die, log);
+      if (type_sp)
+        return type_sp;
+    }
+  }
+
+  DEBUG_PRINTF("0x%8.8" PRIx64 ": %s (\"%s\") type => 0x%8.8lx\n", die.GetID(),
+               DW_TAG_value_to_name(tag), type_name_cstr,
+               encoding_uid.Reference());
+
+  switch (tag) {
+  default:
+    break;
+
+  case DW_TAG_unspecified_type:
+    if (attrs.name == "nullptr_t" || attrs.name == "decltype(nullptr)") {
+      resolve_state = Type::ResolveState::Full;
+      clang_type = m_ast.GetBasicType(eBasicTypeNullPtr);
       break;
     }
+    // Fall through to base type below in case we can handle the type
+    // there...
+    LLVM_FALLTHROUGH;
 
-    if (!clang_type && (encoding_data_type == Type::eEncodingIsPointerUID ||
-                        encoding_data_type == Type::eEncodingIsTypedefUID)) {
-      if (tag == DW_TAG_pointer_type) {
-        DWARFDIE target_die = die.GetReferencedDIE(DW_AT_type);
-
-        if (target_die.GetAttributeValueAsUnsigned(DW_AT_APPLE_block, 0)) {
-          // Blocks have a __FuncPtr inside them which is a pointer to a
-          // function of the proper type.
-
-          for (DWARFDIE child_die = target_die.GetFirstChild();
-               child_die.IsValid(); child_die = child_die.GetSibling()) {
-            if (!strcmp(child_die.GetAttributeValueAsString(DW_AT_name, ""),
-                        "__FuncPtr")) {
-              DWARFDIE function_pointer_type =
-                  child_die.GetReferencedDIE(DW_AT_type);
-
-              if (function_pointer_type) {
-                DWARFDIE function_type =
-                    function_pointer_type.GetReferencedDIE(DW_AT_type);
-
-                bool function_type_is_new_pointer;
-                TypeSP lldb_function_type_sp = ParseTypeFromDWARF(
-                    sc, function_type, &function_type_is_new_pointer);
-
-                if (lldb_function_type_sp) {
-                  clang_type = m_ast.CreateBlockPointerType(
-                      lldb_function_type_sp->GetForwardCompilerType());
-                  encoding_data_type = Type::eEncodingIsUID;
-                  attrs.type.Clear();
-                  resolve_state = Type::eResolveStateFull;
-                }
-              }
+  case DW_TAG_base_type:
+    resolve_state = Type::ResolveState::Full;
+    clang_type = m_ast.GetBuiltinTypeForDWARFEncodingAndBitSize(
+        attrs.name.GetStringRef(), attrs.encoding,
+        attrs.byte_size.getValueOr(0) * 8);
+    break;
 
-              break;
+  case DW_TAG_pointer_type:
+    encoding_data_type = Type::eEncodingIsPointerUID;
+    break;
+  case DW_TAG_reference_type:
+    encoding_data_type = Type::eEncodingIsLValueReferenceUID;
+    break;
+  case DW_TAG_rvalue_reference_type:
+    encoding_data_type = Type::eEncodingIsRValueReferenceUID;
+    break;
+  case DW_TAG_typedef:
+    encoding_data_type = Type::eEncodingIsTypedefUID;
+    break;
+  case DW_TAG_const_type:
+    encoding_data_type = Type::eEncodingIsConstUID;
+    break;
+  case DW_TAG_restrict_type:
+    encoding_data_type = Type::eEncodingIsRestrictUID;
+    break;
+  case DW_TAG_volatile_type:
+    encoding_data_type = Type::eEncodingIsVolatileUID;
+    break;
+  case DW_TAG_atomic_type:
+    encoding_data_type = Type::eEncodingIsAtomicUID;
+    break;
+  }
+
+  if (!clang_type && (encoding_data_type == Type::eEncodingIsPointerUID ||
+                      encoding_data_type == Type::eEncodingIsTypedefUID)) {
+    if (tag == DW_TAG_pointer_type) {
+      DWARFDIE target_die = die.GetReferencedDIE(DW_AT_type);
+
+      if (target_die.GetAttributeValueAsUnsigned(DW_AT_APPLE_block, 0)) {
+        // Blocks have a __FuncPtr inside them which is a pointer to a
+        // function of the proper type.
+
+        for (DWARFDIE child_die = target_die.GetFirstChild();
+             child_die.IsValid(); child_die = child_die.GetSibling()) {
+          if (!strcmp(child_die.GetAttributeValueAsString(DW_AT_name, ""),
+                      "__FuncPtr")) {
+            DWARFDIE function_pointer_type =
+                child_die.GetReferencedDIE(DW_AT_type);
+
+            if (function_pointer_type) {
+              DWARFDIE function_type =
+                  function_pointer_type.GetReferencedDIE(DW_AT_type);
+
+              bool function_type_is_new_pointer;
+              TypeSP lldb_function_type_sp = ParseTypeFromDWARF(
+                  sc, function_type, &function_type_is_new_pointer);
+
+              if (lldb_function_type_sp) {
+                clang_type = m_ast.CreateBlockPointerType(
+                    lldb_function_type_sp->GetForwardCompilerType());
+                encoding_data_type = Type::eEncodingIsUID;
+                attrs.type.Clear();
+                resolve_state = Type::ResolveState::Full;
+              }
             }
+
+            break;
           }
         }
       }
+    }
 
-      if (cu_language == eLanguageTypeObjC ||
-          cu_language == eLanguageTypeObjC_plus_plus) {
-        if (attrs.name) {
-          static ConstString g_objc_type_name_id("id");
-          static ConstString g_objc_type_name_Class("Class");
-          static ConstString g_objc_type_name_selector("SEL");
+    if (cu_language == eLanguageTypeObjC ||
+        cu_language == eLanguageTypeObjC_plus_plus) {
+      if (attrs.name) {
+        if (attrs.name == "id") {
+          if (log)
+            dwarf->GetObjectFile()->GetModule()->LogMessage(
+                log,
+                "SymbolFileDWARF::ParseType (die = 0x%8.8x) %s '%s' "
+                "is Objective-C 'id' built-in type.",
+                die.GetOffset(), die.GetTagAsCString(), die.GetName());
+          clang_type = m_ast.GetBasicType(eBasicTypeObjCID);
+          encoding_data_type = Type::eEncodingIsUID;
+          attrs.type.Clear();
+          resolve_state = Type::ResolveState::Full;
+        } else if (attrs.name == "Class") {
+          if (log)
+            dwarf->GetObjectFile()->GetModule()->LogMessage(
+                log,
+                "SymbolFileDWARF::ParseType (die = 0x%8.8x) %s '%s' "
+                "is Objective-C 'Class' built-in type.",
+                die.GetOffset(), die.GetTagAsCString(), die.GetName());
+          clang_type = m_ast.GetBasicType(eBasicTypeObjCClass);
+          encoding_data_type = Type::eEncodingIsUID;
+          attrs.type.Clear();
+          resolve_state = Type::ResolveState::Full;
+        } else if (attrs.name == "SEL") {
+          if (log)
+            dwarf->GetObjectFile()->GetModule()->LogMessage(
+                log,
+                "SymbolFileDWARF::ParseType (die = 0x%8.8x) %s '%s' "
+                "is Objective-C 'selector' built-in type.",
+                die.GetOffset(), die.GetTagAsCString(), die.GetName());
+          clang_type = m_ast.GetBasicType(eBasicTypeObjCSel);
+          encoding_data_type = Type::eEncodingIsUID;
+          attrs.type.Clear();
+          resolve_state = Type::ResolveState::Full;
+        }
+      } else if (encoding_data_type == Type::eEncodingIsPointerUID &&
+                 attrs.type.IsValid()) {
+        // Clang sometimes erroneously emits id as objc_object*.  In that
+        // case we fix up the type to "id".
 
-          if (attrs.name == g_objc_type_name_id) {
-            if (log)
-              dwarf->GetObjectFile()->GetModule()->LogMessage(
-                  log,
-                  "SymbolFileDWARF::ParseType (die = 0x%8.8x) %s '%s' "
-                  "is Objective-C 'id' built-in type.",
-                  die.GetOffset(), die.GetTagAsCString(), die.GetName());
-            clang_type = m_ast.GetBasicType(eBasicTypeObjCID);
-            encoding_data_type = Type::eEncodingIsUID;
-            attrs.type.Clear();
-            resolve_state = Type::eResolveStateFull;
+        const DWARFDIE encoding_die = attrs.type.Reference();
 
-          } else if (attrs.name == g_objc_type_name_Class) {
+        if (encoding_die && encoding_die.Tag() == DW_TAG_structure_type) {
+          llvm::StringRef struct_name = encoding_die.GetName();
+          if (struct_name == "objc_object") {
             if (log)
               dwarf->GetObjectFile()->GetModule()->LogMessage(
                   log,
-                  "SymbolFileDWARF::ParseType (die = 0x%8.8x) %s '%s' "
-                  "is Objective-C 'Class' built-in type.",
+                  "SymbolFileDWARF::ParseType (die = 0x%8.8x) %s "
+                  "'%s' is 'objc_object*', which we overrode to "
+                  "'id'.",
                   die.GetOffset(), die.GetTagAsCString(), die.GetName());
-            clang_type = m_ast.GetBasicType(eBasicTypeObjCClass);
-            encoding_data_type = Type::eEncodingIsUID;
-            attrs.type.Clear();
-            resolve_state = Type::eResolveStateFull;
-          } else if (attrs.name == g_objc_type_name_selector) {
-            if (log)
-              dwarf->GetObjectFile()->GetModule()->LogMessage(
-                  log,
-                  "SymbolFileDWARF::ParseType (die = 0x%8.8x) %s '%s' "
-                  "is Objective-C 'selector' built-in type.",
-                  die.GetOffset(), die.GetTagAsCString(), die.GetName());
-            clang_type = m_ast.GetBasicType(eBasicTypeObjCSel);
+            clang_type = m_ast.GetBasicType(eBasicTypeObjCID);
             encoding_data_type = Type::eEncodingIsUID;
             attrs.type.Clear();
-            resolve_state = Type::eResolveStateFull;
-          }
-        } else if (encoding_data_type == Type::eEncodingIsPointerUID &&
-                   attrs.type.IsValid()) {
-          // Clang sometimes erroneously emits id as objc_object*.  In that
-          // case we fix up the type to "id".
-
-          const DWARFDIE encoding_die = attrs.type.Reference();
-
-          if (encoding_die && encoding_die.Tag() == DW_TAG_structure_type) {
-            if (const char *struct_name = encoding_die.GetName()) {
-              if (!strcmp(struct_name, "objc_object")) {
-                if (log)
-                  dwarf->GetObjectFile()->GetModule()->LogMessage(
-                      log,
-                      "SymbolFileDWARF::ParseType (die = 0x%8.8x) %s "
-                      "'%s' is 'objc_object*', which we overrode to "
-                      "'id'.",
-                      die.GetOffset(), die.GetTagAsCString(), die.GetName());
-                clang_type = m_ast.GetBasicType(eBasicTypeObjCID);
-                encoding_data_type = Type::eEncodingIsUID;
-                attrs.type.Clear();
-                resolve_state = Type::eResolveStateFull;
-              }
-            }
+            resolve_state = Type::ResolveState::Full;
           }
         }
       }
     }
-
-    type_sp = std::make_shared<Type>(
-        die.GetID(), dwarf, attrs.name, attrs.byte_size, nullptr,
-        dwarf->GetUID(attrs.type.Reference()), encoding_data_type, &attrs.decl,
-        clang_type, resolve_state);
-
-    dwarf->GetDIEToType()[die.GetDIE()] = type_sp.get();
-  } break;
-
-  case DW_TAG_structure_type:
-  case DW_TAG_union_type:
-  case DW_TAG_class_type: {
-    assert((!type_sp && !clang_type) &&
-           "Did not expect partially computed structure-like type");
-    TypeSP struct_like_type_sp = ParseStructureLikeDIE(die, attrs);
-    return UpdateSymbolContextScopeForType(sc, die, struct_like_type_sp);
   }
 
-  case DW_TAG_enumeration_type: {
-    if (attrs.is_forward_declaration) {
-      type_sp = ParseTypeFromDWO(die, log);
-      if (type_sp)
-        return type_sp;
+  type_sp = std::make_shared<Type>(
+      die.GetID(), dwarf, attrs.name, attrs.byte_size, nullptr,
+      dwarf->GetUID(attrs.type.Reference()), encoding_data_type, &attrs.decl,
+      clang_type, resolve_state);
 
-      DWARFDeclContext die_decl_ctx;
-      die.GetDWARFDeclContext(die_decl_ctx);
+  dwarf->GetDIEToType()[die.GetDIE()] = type_sp.get();
+  return type_sp;
+}
 
-      type_sp = dwarf->FindDefinitionTypeForDWARFDeclContext(die_decl_ctx);
+TypeSP DWARFASTParserClang::ParseEnum(const SymbolContext &sc,
+                                      const DWARFDIE &die,
+                                      ParsedDWARFTypeAttributes &attrs) {
+  Log *log(LogChannelDWARF::GetLogIfAny(DWARF_LOG_TYPE_COMPLETION |
+                                        DWARF_LOG_LOOKUPS));
+  SymbolFileDWARF *dwarf = die.GetDWARF();
+  const dw_tag_t tag = die.Tag();
+  TypeSP type_sp;
 
-      if (!type_sp) {
-        SymbolFileDWARFDebugMap *debug_map_symfile =
-            dwarf->GetDebugMapSymfile();
-        if (debug_map_symfile) {
-          // We weren't able to find a full declaration in this DWARF,
-          // see if we have a declaration anywhere else...
-          type_sp = debug_map_symfile->FindDefinitionTypeForDWARFDeclContext(
-              die_decl_ctx);
-        }
-      }
+  if (attrs.is_forward_declaration) {
+    type_sp = ParseTypeFromClangModule(sc, die, log);
+    if (type_sp)
+      return type_sp;
 
-      if (type_sp) {
-        if (log) {
-          dwarf->GetObjectFile()->GetModule()->LogMessage(
-              log,
-              "SymbolFileDWARF(%p) - 0x%8.8x: %s type \"%s\" is a "
-              "forward declaration, complete type is 0x%8.8" PRIx64,
-              static_cast<void *>(this), die.GetOffset(),
-              DW_TAG_value_to_name(tag), attrs.name.GetCString(),
-              type_sp->GetID());
-        }
+    DWARFDeclContext die_decl_ctx;
+    die.GetDWARFDeclContext(die_decl_ctx);
 
-        // We found a real definition for this type elsewhere so lets use
-        // it and cache the fact that we found a complete type for this
-        // die
-        dwarf->GetDIEToType()[die.GetDIE()] = type_sp.get();
-        clang::DeclContext *defn_decl_ctx =
-            GetCachedClangDeclContextForDIE(dwarf->GetDIE(type_sp->GetID()));
-        if (defn_decl_ctx)
-          LinkDeclContextToDIE(defn_decl_ctx, die);
-        return type_sp;
+    type_sp = dwarf->FindDefinitionTypeForDWARFDeclContext(die_decl_ctx);
+
+    if (!type_sp) {
+      SymbolFileDWARFDebugMap *debug_map_symfile = dwarf->GetDebugMapSymfile();
+      if (debug_map_symfile) {
+        // We weren't able to find a full declaration in this DWARF,
+        // see if we have a declaration anywhere else...
+        type_sp = debug_map_symfile->FindDefinitionTypeForDWARFDeclContext(
+            die_decl_ctx);
       }
     }
-    DEBUG_PRINTF("0x%8.8" PRIx64 ": %s (\"%s\")\n", die.GetID(),
-                 DW_TAG_value_to_name(tag), type_name_cstr);
-
-    CompilerType enumerator_clang_type;
-    clang_type.SetCompilerType(
-        &m_ast, dwarf->GetForwardDeclDieToClangType().lookup(die.GetDIE()));
-    if (!clang_type) {
-      if (attrs.type.IsValid()) {
-        Type *enumerator_type =
-            dwarf->ResolveTypeUID(attrs.type.Reference(), true);
-        if (enumerator_type)
-          enumerator_clang_type = enumerator_type->GetFullCompilerType();
-      }
 
-      if (!enumerator_clang_type) {
-        if (attrs.byte_size) {
-          enumerator_clang_type =
-              m_ast.GetBuiltinTypeForDWARFEncodingAndBitSize(
-                  NULL, DW_ATE_signed, *attrs.byte_size * 8);
-        } else {
-          enumerator_clang_type = m_ast.GetBasicType(eBasicTypeInt);
-        }
+    if (type_sp) {
+      if (log) {
+        dwarf->GetObjectFile()->GetModule()->LogMessage(
+            log,
+            "SymbolFileDWARF(%p) - 0x%8.8x: %s type \"%s\" is a "
+            "forward declaration, complete type is 0x%8.8" PRIx64,
+            static_cast<void *>(this), die.GetOffset(),
+            DW_TAG_value_to_name(tag), attrs.name.GetCString(),
+            type_sp->GetID());
       }
 
-      clang_type = m_ast.CreateEnumerationType(
-          attrs.name.GetCString(),
-          GetClangDeclContextContainingDIE(die, nullptr), attrs.decl,
-          enumerator_clang_type, attrs.is_scoped_enum);
-    } else {
-      enumerator_clang_type =
-          m_ast.GetEnumerationIntegerType(clang_type.GetOpaqueQualType());
+      // We found a real definition for this type elsewhere so lets use
+      // it and cache the fact that we found a complete type for this
+      // die
+      dwarf->GetDIEToType()[die.GetDIE()] = type_sp.get();
+      clang::DeclContext *defn_decl_ctx =
+          GetCachedClangDeclContextForDIE(dwarf->GetDIE(type_sp->GetID()));
+      if (defn_decl_ctx)
+        LinkDeclContextToDIE(defn_decl_ctx, die);
+      return type_sp;
     }
+  }
+  DEBUG_PRINTF("0x%8.8" PRIx64 ": %s (\"%s\")\n", die.GetID(),
+               DW_TAG_value_to_name(tag), type_name_cstr);
 
-    LinkDeclContextToDIE(ClangASTContext::GetDeclContextForType(clang_type),
-                         die);
-
-    type_sp = std::make_shared<Type>(
-        die.GetID(), dwarf, attrs.name, attrs.byte_size, nullptr,
-        dwarf->GetUID(attrs.type.Reference()), Type::eEncodingIsUID,
-        &attrs.decl, clang_type, Type::eResolveStateForward);
+  CompilerType enumerator_clang_type;
+  CompilerType clang_type;
+  clang_type.SetCompilerType(
+      &m_ast, dwarf->GetForwardDeclDieToClangType().lookup(die.GetDIE()));
+  if (!clang_type) {
+    if (attrs.type.IsValid()) {
+      Type *enumerator_type =
+          dwarf->ResolveTypeUID(attrs.type.Reference(), true);
+      if (enumerator_type)
+        enumerator_clang_type = enumerator_type->GetFullCompilerType();
+    }
 
-    if (ClangASTContext::StartTagDeclarationDefinition(clang_type)) {
-      if (die.HasChildren()) {
-        bool is_signed = false;
-        enumerator_clang_type.IsIntegerType(is_signed);
-        ParseChildEnumerators(clang_type, is_signed,
-                              type_sp->GetByteSize().getValueOr(0), die);
+    if (!enumerator_clang_type) {
+      if (attrs.byte_size) {
+        enumerator_clang_type = m_ast.GetBuiltinTypeForDWARFEncodingAndBitSize(
+            "", DW_ATE_signed, *attrs.byte_size * 8);
+      } else {
+        enumerator_clang_type = m_ast.GetBasicType(eBasicTypeInt);
       }
-      ClangASTContext::CompleteTagDeclarationDefinition(clang_type);
-    } else {
-      dwarf->GetObjectFile()->GetModule()->ReportError(
-          "DWARF DIE at 0x%8.8x named \"%s\" was not able to start its "
-          "definition.\nPlease file a bug and attach the file at the "
-          "start of this error message",
-          die.GetOffset(), attrs.name.GetCString());
     }
-  } break;
 
-  case DW_TAG_inlined_subroutine:
-  case DW_TAG_subprogram:
-  case DW_TAG_subroutine_type: {
-    bool is_variadic = false;
-    bool is_static = false;
-    bool has_template_params = false;
+    clang_type = m_ast.CreateEnumerationType(
+        attrs.name.GetCString(), GetClangDeclContextContainingDIE(die, nullptr),
+        attrs.decl, enumerator_clang_type, attrs.is_scoped_enum);
+  } else {
+    enumerator_clang_type =
+        m_ast.GetEnumerationIntegerType(clang_type.GetOpaqueQualType());
+  }
 
-    unsigned type_quals = 0;
+  LinkDeclContextToDIE(ClangASTContext::GetDeclContextForType(clang_type), die);
 
-    std::string object_pointer_name;
-    if (attrs.object_pointer) {
-      const char *object_pointer_name_cstr = attrs.object_pointer.GetName();
-      if (object_pointer_name_cstr)
-        object_pointer_name = object_pointer_name_cstr;
-    }
+  type_sp = std::make_shared<Type>(
+      die.GetID(), dwarf, attrs.name, attrs.byte_size, nullptr,
+      dwarf->GetUID(attrs.type.Reference()), Type::eEncodingIsUID, &attrs.decl,
+      clang_type, Type::ResolveState::Forward);
 
-    DEBUG_PRINTF("0x%8.8" PRIx64 ": %s (\"%s\")\n", die.GetID(),
-                 DW_TAG_value_to_name(tag), type_name_cstr);
+  if (ClangASTContext::StartTagDeclarationDefinition(clang_type)) {
+    if (die.HasChildren()) {
+      bool is_signed = false;
+      enumerator_clang_type.IsIntegerType(is_signed);
+      ParseChildEnumerators(clang_type, is_signed,
+                            type_sp->GetByteSize().getValueOr(0), die);
+    }
+    ClangASTContext::CompleteTagDeclarationDefinition(clang_type);
+  } else {
+    dwarf->GetObjectFile()->GetModule()->ReportError(
+        "DWARF DIE at 0x%8.8x named \"%s\" was not able to start its "
+        "definition.\nPlease file a bug and attach the file at the "
+        "start of this error message",
+        die.GetOffset(), attrs.name.GetCString());
+  }
+  return type_sp;
+}
 
-    CompilerType return_clang_type;
-    Type *func_type = NULL;
+TypeSP DWARFASTParserClang::ParseSubroutine(const DWARFDIE &die,
+                           ParsedDWARFTypeAttributes &attrs) {
+  Log *log(LogChannelDWARF::GetLogIfAny(DWARF_LOG_TYPE_COMPLETION |
+                                        DWARF_LOG_LOOKUPS));
 
-    if (attrs.type.IsValid())
-      func_type = dwarf->ResolveTypeUID(attrs.type.Reference(), true);
+  SymbolFileDWARF *dwarf = die.GetDWARF();
+  const dw_tag_t tag = die.Tag();
 
-    if (func_type)
-      return_clang_type = func_type->GetForwardCompilerType();
-    else
-      return_clang_type = m_ast.GetBasicType(eBasicTypeVoid);
+  bool is_variadic = false;
+  bool is_static = false;
+  bool has_template_params = false;
 
-    std::vector<CompilerType> function_param_types;
-    std::vector<clang::ParmVarDecl *> function_param_decls;
+  unsigned type_quals = 0;
 
-    // Parse the function children for the parameters
+  std::string object_pointer_name;
+  if (attrs.object_pointer) {
+    const char *object_pointer_name_cstr = attrs.object_pointer.GetName();
+    if (object_pointer_name_cstr)
+      object_pointer_name = object_pointer_name_cstr;
+  }
 
-    DWARFDIE decl_ctx_die;
-    clang::DeclContext *containing_decl_ctx =
-        GetClangDeclContextContainingDIE(die, &decl_ctx_die);
-    const clang::Decl::Kind containing_decl_kind =
-        containing_decl_ctx->getDeclKind();
+  DEBUG_PRINTF("0x%8.8" PRIx64 ": %s (\"%s\")\n", die.GetID(),
+               DW_TAG_value_to_name(tag), type_name_cstr);
 
-    bool is_cxx_method = DeclKindIsCXXClass(containing_decl_kind);
-    // Start off static. This will be set to false in
-    // ParseChildParameters(...) if we find a "this" parameters as the
-    // first parameter
-    if (is_cxx_method) {
-      is_static = true;
-    }
+  CompilerType return_clang_type;
+  Type *func_type = NULL;
+
+  if (attrs.type.IsValid())
+    func_type = dwarf->ResolveTypeUID(attrs.type.Reference(), true);
+
+  if (func_type)
+    return_clang_type = func_type->GetForwardCompilerType();
+  else
+    return_clang_type = m_ast.GetBasicType(eBasicTypeVoid);
+
+  std::vector<CompilerType> function_param_types;
+  std::vector<clang::ParmVarDecl *> function_param_decls;
+
+  // Parse the function children for the parameters
+
+  DWARFDIE decl_ctx_die;
+  clang::DeclContext *containing_decl_ctx =
+      GetClangDeclContextContainingDIE(die, &decl_ctx_die);
+  const clang::Decl::Kind containing_decl_kind =
+      containing_decl_ctx->getDeclKind();
+
+  bool is_cxx_method = DeclKindIsCXXClass(containing_decl_kind);
+  // Start off static. This will be set to false in
+  // ParseChildParameters(...) if we find a "this" parameters as the
+  // first parameter
+  if (is_cxx_method) {
+    is_static = true;
+  }
+
+  if (die.HasChildren()) {
+    bool skip_artificial = true;
+    ParseChildParameters(containing_decl_ctx, die, skip_artificial, is_static,
+                         is_variadic, has_template_params,
+                         function_param_types, function_param_decls,
+                         type_quals);
+  }
+
+  bool ignore_containing_context = false;
+  // Check for templatized class member functions. If we had any
+  // DW_TAG_template_type_parameter or DW_TAG_template_value_parameter
+  // the DW_TAG_subprogram DIE, then we can't let this become a method in
+  // a class. Why? Because templatized functions are only emitted if one
+  // of the templatized methods is used in the current compile unit and
+  // we will end up with classes that may or may not include these member
+  // functions and this means one class won't match another class
+  // definition and it affects our ability to use a class in the clang
+  // expression parser. So for the greater good, we currently must not
+  // allow any template member functions in a class definition.
+  if (is_cxx_method && has_template_params) {
+    ignore_containing_context = true;
+    is_cxx_method = false;
+  }
+
+  // clang_type will get the function prototype clang type after this
+  // call
+  CompilerType clang_type = m_ast.CreateFunctionType(
+      return_clang_type, function_param_types.data(),
+      function_param_types.size(), is_variadic, type_quals);
 
-    if (die.HasChildren()) {
-      bool skip_artificial = true;
-      ParseChildParameters(containing_decl_ctx, die, skip_artificial, is_static,
-                           is_variadic, has_template_params,
-                           function_param_types, function_param_decls,
-                           type_quals);
-    }
-
-    bool ignore_containing_context = false;
-    // Check for templatized class member functions. If we had any
-    // DW_TAG_template_type_parameter or DW_TAG_template_value_parameter
-    // the DW_TAG_subprogram DIE, then we can't let this become a method in
-    // a class. Why? Because templatized functions are only emitted if one
-    // of the templatized methods is used in the current compile unit and
-    // we will end up with classes that may or may not include these member
-    // functions and this means one class won't match another class
-    // definition and it affects our ability to use a class in the clang
-    // expression parser. So for the greater good, we currently must not
-    // allow any template member functions in a class definition.
-    if (is_cxx_method && has_template_params) {
-      ignore_containing_context = true;
-      is_cxx_method = false;
-    }
-
-    // clang_type will get the function prototype clang type after this
-    // call
-    clang_type = m_ast.CreateFunctionType(
-        return_clang_type, function_param_types.data(),
-        function_param_types.size(), is_variadic, type_quals);
-
-    if (attrs.name) {
-      bool type_handled = false;
-      if (tag == DW_TAG_subprogram || tag == DW_TAG_inlined_subroutine) {
-        ObjCLanguage::MethodName objc_method(attrs.name.GetStringRef(), true);
-        if (objc_method.IsValid(true)) {
-          CompilerType class_opaque_type;
-          ConstString class_name(objc_method.GetClassName());
-          if (class_name) {
-            TypeSP complete_objc_class_type_sp(
-                dwarf->FindCompleteObjCDefinitionTypeForDIE(DWARFDIE(),
-                                                            class_name, false));
-
-            if (complete_objc_class_type_sp) {
-              CompilerType type_clang_forward_type =
-                  complete_objc_class_type_sp->GetForwardCompilerType();
-              if (ClangASTContext::IsObjCObjectOrInterfaceType(
-                      type_clang_forward_type))
-                class_opaque_type = type_clang_forward_type;
-            }
+  if (attrs.name) {
+    bool type_handled = false;
+    if (tag == DW_TAG_subprogram || tag == DW_TAG_inlined_subroutine) {
+      ObjCLanguage::MethodName objc_method(attrs.name.GetStringRef(), true);
+      if (objc_method.IsValid(true)) {
+        CompilerType class_opaque_type;
+        ConstString class_name(objc_method.GetClassName());
+        if (class_name) {
+          TypeSP complete_objc_class_type_sp(
+              dwarf->FindCompleteObjCDefinitionTypeForDIE(DWARFDIE(),
+                                                          class_name, false));
+
+          if (complete_objc_class_type_sp) {
+            CompilerType type_clang_forward_type =
+                complete_objc_class_type_sp->GetForwardCompilerType();
+            if (ClangASTContext::IsObjCObjectOrInterfaceType(
+                    type_clang_forward_type))
+              class_opaque_type = type_clang_forward_type;
           }
+        }
 
-          if (class_opaque_type) {
-            // If accessibility isn't set to anything valid, assume public
-            // for now...
-            if (attrs.accessibility == eAccessNone)
-              attrs.accessibility = eAccessPublic;
-
-            clang::ObjCMethodDecl *objc_method_decl =
-                m_ast.AddMethodToObjCObjectType(
-                    class_opaque_type, attrs.name.GetCString(), clang_type,
-                    attrs.accessibility, attrs.is_artificial, is_variadic);
-            type_handled = objc_method_decl != NULL;
-            if (type_handled) {
-              LinkDeclContextToDIE(
-                  ClangASTContext::GetAsDeclContext(objc_method_decl), die);
-              m_ast.SetMetadataAsUserID(objc_method_decl, die.GetID());
-            } else {
-              dwarf->GetObjectFile()->GetModule()->ReportError(
-                  "{0x%8.8x}: invalid Objective-C method 0x%4.4x (%s), "
-                  "please file a bug and attach the file at the start of "
-                  "this error message",
-                  die.GetOffset(), tag, DW_TAG_value_to_name(tag));
-            }
+        if (class_opaque_type) {
+          // If accessibility isn't set to anything valid, assume public
+          // for now...
+          if (attrs.accessibility == eAccessNone)
+            attrs.accessibility = eAccessPublic;
+
+          clang::ObjCMethodDecl *objc_method_decl =
+              m_ast.AddMethodToObjCObjectType(
+                  class_opaque_type, attrs.name.GetCString(), clang_type,
+                  attrs.accessibility, attrs.is_artificial, is_variadic,
+                  attrs.is_objc_direct_call);
+          type_handled = objc_method_decl != NULL;
+          if (type_handled) {
+            LinkDeclContextToDIE(objc_method_decl, die);
+            m_ast.SetMetadataAsUserID(objc_method_decl, die.GetID());
+          } else {
+            dwarf->GetObjectFile()->GetModule()->ReportError(
+                "{0x%8.8x}: invalid Objective-C method 0x%4.4x (%s), "
+                "please file a bug and attach the file at the start of "
+                "this error message",
+                die.GetOffset(), tag, DW_TAG_value_to_name(tag));
           }
-        } else if (is_cxx_method) {
-          // Look at the parent of this DIE and see if is is a class or
-          // struct and see if this is actually a C++ method
-          Type *class_type = dwarf->ResolveType(decl_ctx_die);
-          if (class_type) {
-            bool alternate_defn = false;
-            if (class_type->GetID() != decl_ctx_die.GetID() ||
-                decl_ctx_die.GetContainingDWOModuleDIE()) {
-              alternate_defn = true;
-
-              // We uniqued the parent class of this function to another
-              // class so we now need to associate all dies under
-              // "decl_ctx_die" to DIEs in the DIE for "class_type"...
-              DWARFDIE class_type_die = dwarf->GetDIE(class_type->GetID());
-
-              if (class_type_die) {
-                std::vector<DWARFDIE> failures;
-
-                CopyUniqueClassMethodTypes(decl_ctx_die, class_type_die,
-                                           class_type, failures);
-
-                // FIXME do something with these failures that's smarter
-                // than
-                // just dropping them on the ground.  Unfortunately classes
-                // don't like having stuff added to them after their
-                // definitions are complete...
-
-                type_ptr = dwarf->GetDIEToType()[die.GetDIE()];
-                if (type_ptr && type_ptr != DIE_IS_BEING_PARSED) {
-                  type_sp = type_ptr->shared_from_this();
-                  break;
-                }
+        }
+      } else if (is_cxx_method) {
+        // Look at the parent of this DIE and see if is is a class or
+        // struct and see if this is actually a C++ method
+        Type *class_type = dwarf->ResolveType(decl_ctx_die);
+        if (class_type) {
+          bool alternate_defn = false;
+          if (class_type->GetID() != decl_ctx_die.GetID() ||
+              IsClangModuleFwdDecl(decl_ctx_die)) {
+            alternate_defn = true;
+
+            // We uniqued the parent class of this function to another
+            // class so we now need to associate all dies under
+            // "decl_ctx_die" to DIEs in the DIE for "class_type"...
+            DWARFDIE class_type_die = dwarf->GetDIE(class_type->GetID());
+
+            if (class_type_die) {
+              std::vector<DWARFDIE> failures;
+
+              CopyUniqueClassMethodTypes(decl_ctx_die, class_type_die,
+                                         class_type, failures);
+
+              // FIXME do something with these failures that's
+              // smarter than just dropping them on the ground.
+              // Unfortunately classes don't like having stuff added
+              // to them after their definitions are complete...
+
+              Type *type_ptr = dwarf->GetDIEToType()[die.GetDIE()];
+              if (type_ptr && type_ptr != DIE_IS_BEING_PARSED) {
+                return type_ptr->shared_from_this();
               }
             }
+          }
 
-            if (attrs.specification.IsValid()) {
-              // We have a specification which we are going to base our
-              // function prototype off of, so we need this type to be
-              // completed so that the m_die_to_decl_ctx for the method in
-              // the specification has a valid clang decl context.
-              class_type->GetForwardCompilerType();
-              // If we have a specification, then the function type should
-              // have been made with the specification and not with this
-              // die.
-              DWARFDIE spec_die = attrs.specification.Reference();
-              clang::DeclContext *spec_clang_decl_ctx =
-                  GetClangDeclContextForDIE(spec_die);
-              if (spec_clang_decl_ctx) {
-                LinkDeclContextToDIE(spec_clang_decl_ctx, die);
-              } else {
-                dwarf->GetObjectFile()->GetModule()->ReportWarning(
-                    "0x%8.8" PRIx64 ": DW_AT_specification(0x%8.8x"
-                    ") has no decl\n",
-                    die.GetID(), spec_die.GetOffset());
-              }
-              type_handled = true;
-            } else if (attrs.abstract_origin.IsValid()) {
-              // We have a specification which we are going to base our
-              // function prototype off of, so we need this type to be
-              // completed so that the m_die_to_decl_ctx for the method in
-              // the abstract origin has a valid clang decl context.
-              class_type->GetForwardCompilerType();
-
-              DWARFDIE abs_die = attrs.abstract_origin.Reference();
-              clang::DeclContext *abs_clang_decl_ctx =
-                  GetClangDeclContextForDIE(abs_die);
-              if (abs_clang_decl_ctx) {
-                LinkDeclContextToDIE(abs_clang_decl_ctx, die);
-              } else {
-                dwarf->GetObjectFile()->GetModule()->ReportWarning(
-                    "0x%8.8" PRIx64 ": DW_AT_abstract_origin(0x%8.8x"
-                    ") has no decl\n",
-                    die.GetID(), abs_die.GetOffset());
-              }
-              type_handled = true;
+          if (attrs.specification.IsValid()) {
+            // We have a specification which we are going to base our
+            // function prototype off of, so we need this type to be
+            // completed so that the m_die_to_decl_ctx for the method in
+            // the specification has a valid clang decl context.
+            class_type->GetForwardCompilerType();
+            // If we have a specification, then the function type should
+            // have been made with the specification and not with this
+            // die.
+            DWARFDIE spec_die = attrs.specification.Reference();
+            clang::DeclContext *spec_clang_decl_ctx =
+                GetClangDeclContextForDIE(spec_die);
+            if (spec_clang_decl_ctx) {
+              LinkDeclContextToDIE(spec_clang_decl_ctx, die);
+            } else {
+              dwarf->GetObjectFile()->GetModule()->ReportWarning(
+                  "0x%8.8" PRIx64 ": DW_AT_specification(0x%8.8x"
+                  ") has no decl\n",
+                  die.GetID(), spec_die.GetOffset());
+            }
+            type_handled = true;
+          } else if (attrs.abstract_origin.IsValid()) {
+            // We have a specification which we are going to base our
+            // function prototype off of, so we need this type to be
+            // completed so that the m_die_to_decl_ctx for the method in
+            // the abstract origin has a valid clang decl context.
+            class_type->GetForwardCompilerType();
+
+            DWARFDIE abs_die = attrs.abstract_origin.Reference();
+            clang::DeclContext *abs_clang_decl_ctx =
+                GetClangDeclContextForDIE(abs_die);
+            if (abs_clang_decl_ctx) {
+              LinkDeclContextToDIE(abs_clang_decl_ctx, die);
             } else {
-              CompilerType class_opaque_type =
-                  class_type->GetForwardCompilerType();
-              if (ClangASTContext::IsCXXClassType(class_opaque_type)) {
-                if (class_opaque_type.IsBeingDefined() || alternate_defn) {
-                  if (!is_static && !die.HasChildren()) {
-                    // We have a C++ member function with no children (this
-                    // pointer!) and clang will get mad if we try and make
-                    // a function that isn't well formed in the DWARF, so
-                    // we will just skip it...
-                    type_handled = true;
-                  } else {
-                    bool add_method = true;
-                    if (alternate_defn) {
-                      // If an alternate definition for the class exists,
-                      // then add the method only if an equivalent is not
-                      // already present.
-                      clang::CXXRecordDecl *record_decl =
-                          m_ast.GetAsCXXRecordDecl(
-                              class_opaque_type.GetOpaqueQualType());
-                      if (record_decl) {
-                        for (auto method_iter = record_decl->method_begin();
-                             method_iter != record_decl->method_end();
-                             method_iter++) {
-                          clang::CXXMethodDecl *method_decl = *method_iter;
-                          if (method_decl->getNameInfo().getAsString() ==
-                              attrs.name.GetStringRef()) {
-                            if (method_decl->getType() ==
-                                ClangUtil::GetQualType(clang_type)) {
-                              add_method = false;
-                              LinkDeclContextToDIE(
-                                  ClangASTContext::GetAsDeclContext(
-                                      method_decl),
-                                  die);
-                              type_handled = true;
-
-                              break;
-                            }
+              dwarf->GetObjectFile()->GetModule()->ReportWarning(
+                  "0x%8.8" PRIx64 ": DW_AT_abstract_origin(0x%8.8x"
+                  ") has no decl\n",
+                  die.GetID(), abs_die.GetOffset());
+            }
+            type_handled = true;
+          } else {
+            CompilerType class_opaque_type =
+                class_type->GetForwardCompilerType();
+            if (ClangASTContext::IsCXXClassType(class_opaque_type)) {
+              if (class_opaque_type.IsBeingDefined() || alternate_defn) {
+                if (!is_static && !die.HasChildren()) {
+                  // We have a C++ member function with no children (this
+                  // pointer!) and clang will get mad if we try and make
+                  // a function that isn't well formed in the DWARF, so
+                  // we will just skip it...
+                  type_handled = true;
+                } else {
+                  bool add_method = true;
+                  if (alternate_defn) {
+                    // If an alternate definition for the class exists,
+                    // then add the method only if an equivalent is not
+                    // already present.
+                    clang::CXXRecordDecl *record_decl =
+                        m_ast.GetAsCXXRecordDecl(
+                            class_opaque_type.GetOpaqueQualType());
+                    if (record_decl) {
+                      for (auto method_iter = record_decl->method_begin();
+                           method_iter != record_decl->method_end();
+                           method_iter++) {
+                        clang::CXXMethodDecl *method_decl = *method_iter;
+                        if (method_decl->getNameInfo().getAsString() ==
+                            attrs.name.GetStringRef()) {
+                          if (method_decl->getType() ==
+                              ClangUtil::GetQualType(clang_type)) {
+                            add_method = false;
+                            LinkDeclContextToDIE(method_decl, die);
+                            type_handled = true;
+
+                            break;
                           }
                         }
                       }
                     }
+                  }
 
-                    if (add_method) {
-                      llvm::PrettyStackTraceFormat stack_trace(
-                          "SymbolFileDWARF::ParseType() is adding a method "
-                          "%s to class %s in DIE 0x%8.8" PRIx64 " from %s",
-                          attrs.name.GetCString(),
-                          class_type->GetName().GetCString(), die.GetID(),
-                          dwarf->GetObjectFile()
-                              ->GetFileSpec()
-                              .GetPath()
-                              .c_str());
-
-                      const bool is_attr_used = false;
-                      // Neither GCC 4.2 nor clang++ currently set a valid
-                      // accessibility in the DWARF for C++ methods...
-                      // Default to public for now...
-                      if (attrs.accessibility == eAccessNone)
-                        attrs.accessibility = eAccessPublic;
-
-                      clang::CXXMethodDecl *cxx_method_decl =
-                          m_ast.AddMethodToCXXRecordType(
-                              class_opaque_type.GetOpaqueQualType(),
-                              attrs.name.GetCString(), attrs.mangled_name,
-                              clang_type, attrs.accessibility, attrs.is_virtual,
-                              is_static, attrs.is_inline, attrs.is_explicit,
-                              is_attr_used, attrs.is_artificial);
-
-                      type_handled = cxx_method_decl != NULL;
-                      // Artificial methods are always handled even when we
-                      // don't create a new declaration for them.
-                      type_handled |= attrs.is_artificial;
-
-                      if (cxx_method_decl) {
-                        LinkDeclContextToDIE(
-                            ClangASTContext::GetAsDeclContext(cxx_method_decl),
-                            die);
-
-                        ClangASTMetadata metadata;
-                        metadata.SetUserID(die.GetID());
-
-                        if (!object_pointer_name.empty()) {
-                          metadata.SetObjectPtrName(
-                              object_pointer_name.c_str());
-                          LLDB_LOGF(log,
-                                    "Setting object pointer name: %s on method "
-                                    "object %p.\n",
-                                    object_pointer_name.c_str(),
-                                    static_cast<void *>(cxx_method_decl));
-                        }
-                        m_ast.SetMetadata(cxx_method_decl, metadata);
-                      } else {
-                        ignore_containing_context = true;
+                  if (add_method) {
+                    llvm::PrettyStackTraceFormat stack_trace(
+                        "SymbolFileDWARF::ParseType() is adding a method "
+                        "%s to class %s in DIE 0x%8.8" PRIx64 " from %s",
+                        attrs.name.GetCString(),
+                        class_type->GetName().GetCString(), die.GetID(),
+                        dwarf->GetObjectFile()
+                            ->GetFileSpec()
+                            .GetPath()
+                            .c_str());
+
+                    const bool is_attr_used = false;
+                    // Neither GCC 4.2 nor clang++ currently set a valid
+                    // accessibility in the DWARF for C++ methods...
+                    // Default to public for now...
+                    if (attrs.accessibility == eAccessNone)
+                      attrs.accessibility = eAccessPublic;
+
+                    clang::CXXMethodDecl *cxx_method_decl =
+                        m_ast.AddMethodToCXXRecordType(
+                            class_opaque_type.GetOpaqueQualType(),
+                            attrs.name.GetCString(), attrs.mangled_name,
+                            clang_type, attrs.accessibility, attrs.is_virtual,
+                            is_static, attrs.is_inline, attrs.is_explicit,
+                            is_attr_used, attrs.is_artificial);
+
+                    type_handled = cxx_method_decl != NULL;
+                    // Artificial methods are always handled even when we
+                    // don't create a new declaration for them.
+                    type_handled |= attrs.is_artificial;
+
+                    if (cxx_method_decl) {
+                      LinkDeclContextToDIE(cxx_method_decl, die);
+
+                      ClangASTMetadata metadata;
+                      metadata.SetUserID(die.GetID());
+
+                      if (!object_pointer_name.empty()) {
+                        metadata.SetObjectPtrName(
+                            object_pointer_name.c_str());
+                        LLDB_LOGF(log,
+                                  "Setting object pointer name: %s on method "
+                                  "object %p.\n",
+                                  object_pointer_name.c_str(),
+                                  static_cast<void *>(cxx_method_decl));
                       }
+                      m_ast.SetMetadata(cxx_method_decl, metadata);
+                    } else {
+                      ignore_containing_context = true;
                     }
                   }
-                } else {
-                  // We were asked to parse the type for a method in a
-                  // class, yet the class hasn't been asked to complete
-                  // itself through the clang::ExternalASTSource protocol,
-                  // so we need to just have the class complete itself and
-                  // do things the right way, then our
-                  // DIE should then have an entry in the
-                  // dwarf->GetDIEToType() map. First
-                  // we need to modify the dwarf->GetDIEToType() so it
-                  // doesn't think we are trying to parse this DIE
-                  // anymore...
-                  dwarf->GetDIEToType()[die.GetDIE()] = NULL;
-
-                  // Now we get the full type to force our class type to
-                  // complete itself using the clang::ExternalASTSource
-                  // protocol which will parse all base classes and all
-                  // methods (including the method for this DIE).
-                  class_type->GetFullCompilerType();
-
-                  // The type for this DIE should have been filled in the
-                  // function call above
-                  type_ptr = dwarf->GetDIEToType()[die.GetDIE()];
-                  if (type_ptr && type_ptr != DIE_IS_BEING_PARSED) {
-                    type_sp = type_ptr->shared_from_this();
-                    break;
-                  }
-
-                  // FIXME This is fixing some even uglier behavior but we
-                  // really need to
-                  // uniq the methods of each class as well as the class
-                  // itself. <rdar://problem/11240464>
-                  type_handled = true;
                 }
+              } else {
+                // We were asked to parse the type for a method in a
+                // class, yet the class hasn't been asked to complete
+                // itself through the clang::ExternalASTSource protocol,
+                // so we need to just have the class complete itself and
+                // do things the right way, then our
+                // DIE should then have an entry in the
+                // dwarf->GetDIEToType() map. First
+                // we need to modify the dwarf->GetDIEToType() so it
+                // doesn't think we are trying to parse this DIE
+                // anymore...
+                dwarf->GetDIEToType()[die.GetDIE()] = NULL;
+
+                // Now we get the full type to force our class type to
+                // complete itself using the clang::ExternalASTSource
+                // protocol which will parse all base classes and all
+                // methods (including the method for this DIE).
+                class_type->GetFullCompilerType();
+
+                // The type for this DIE should have been filled in the
+                // function call above
+                Type *type_ptr = dwarf->GetDIEToType()[die.GetDIE()];
+                if (type_ptr && type_ptr != DIE_IS_BEING_PARSED) {
+                  return type_ptr->shared_from_this();
+                }
+
+                // FIXME This is fixing some even uglier behavior but we
+                // really need to
+                // uniq the methods of each class as well as the class
+                // itself. <rdar://problem/11240464>
+                type_handled = true;
               }
             }
           }
         }
       }
+    }
 
-      if (!type_handled) {
-        clang::FunctionDecl *function_decl = nullptr;
-        clang::FunctionDecl *template_function_decl = nullptr;
+    if (!type_handled) {
+      clang::FunctionDecl *function_decl = nullptr;
+      clang::FunctionDecl *template_function_decl = nullptr;
 
-        if (attrs.abstract_origin.IsValid()) {
-          DWARFDIE abs_die = attrs.abstract_origin.Reference();
+      if (attrs.abstract_origin.IsValid()) {
+        DWARFDIE abs_die = attrs.abstract_origin.Reference();
 
-          if (dwarf->ResolveType(abs_die)) {
-            function_decl = llvm::dyn_cast_or_null<clang::FunctionDecl>(
-                GetCachedClangDeclContextForDIE(abs_die));
+        if (dwarf->ResolveType(abs_die)) {
+          function_decl = llvm::dyn_cast_or_null<clang::FunctionDecl>(
+              GetCachedClangDeclContextForDIE(abs_die));
 
-            if (function_decl) {
-              LinkDeclContextToDIE(function_decl, die);
-            }
+          if (function_decl) {
+            LinkDeclContextToDIE(function_decl, die);
           }
         }
+      }
 
-        if (!function_decl) {
-          // We just have a function that isn't part of a class
-          function_decl = m_ast.CreateFunctionDeclaration(
+      if (!function_decl) {
+        // We just have a function that isn't part of a class
+        function_decl = m_ast.CreateFunctionDeclaration(
+            ignore_containing_context ? m_ast.GetTranslationUnitDecl()
+                                      : containing_decl_ctx,
+            attrs.name.GetCString(), clang_type, attrs.storage,
+            attrs.is_inline);
+
+        if (has_template_params) {
+          ClangASTContext::TemplateParameterInfos template_param_infos;
+          ParseTemplateParameterInfos(die, template_param_infos);
+          template_function_decl = m_ast.CreateFunctionDeclaration(
               ignore_containing_context ? m_ast.GetTranslationUnitDecl()
                                         : containing_decl_ctx,
               attrs.name.GetCString(), clang_type, attrs.storage,
               attrs.is_inline);
+          clang::FunctionTemplateDecl *func_template_decl =
+              m_ast.CreateFunctionTemplateDecl(
+                  containing_decl_ctx, template_function_decl,
+                  attrs.name.GetCString(), template_param_infos);
+          m_ast.CreateFunctionTemplateSpecializationInfo(
+              function_decl, func_template_decl, template_param_infos);
+        }
 
-          if (has_template_params) {
-            ClangASTContext::TemplateParameterInfos template_param_infos;
-            ParseTemplateParameterInfos(die, template_param_infos);
-            template_function_decl = m_ast.CreateFunctionDeclaration(
-                ignore_containing_context ? m_ast.GetTranslationUnitDecl()
-                                          : containing_decl_ctx,
-                attrs.name.GetCString(), clang_type, attrs.storage,
-                attrs.is_inline);
-            clang::FunctionTemplateDecl *func_template_decl =
-                m_ast.CreateFunctionTemplateDecl(
-                    containing_decl_ctx, template_function_decl,
-                    attrs.name.GetCString(), template_param_infos);
-            m_ast.CreateFunctionTemplateSpecializationInfo(
-                function_decl, func_template_decl, template_param_infos);
-          }
-
-          lldbassert(function_decl);
+        lldbassert(function_decl);
 
-          if (function_decl) {
-            LinkDeclContextToDIE(function_decl, die);
+        if (function_decl) {
+          LinkDeclContextToDIE(function_decl, die);
 
-            if (!function_param_decls.empty()) {
-              m_ast.SetFunctionParameters(function_decl,
+          if (!function_param_decls.empty()) {
+            m_ast.SetFunctionParameters(function_decl,
+                                        &function_param_decls.front(),
+                                        function_param_decls.size());
+            if (template_function_decl)
+              m_ast.SetFunctionParameters(template_function_decl,
                                           &function_param_decls.front(),
                                           function_param_decls.size());
-              if (template_function_decl)
-                m_ast.SetFunctionParameters(template_function_decl,
-                                            &function_param_decls.front(),
-                                            function_param_decls.size());
-            }
+          }
 
-            ClangASTMetadata metadata;
-            metadata.SetUserID(die.GetID());
+          ClangASTMetadata metadata;
+          metadata.SetUserID(die.GetID());
 
-            if (!object_pointer_name.empty()) {
-              metadata.SetObjectPtrName(object_pointer_name.c_str());
-              LLDB_LOGF(log,
-                        "Setting object pointer name: %s on function "
-                        "object %p.",
-                        object_pointer_name.c_str(),
-                        static_cast<void *>(function_decl));
-            }
-            m_ast.SetMetadata(function_decl, metadata);
+          if (!object_pointer_name.empty()) {
+            metadata.SetObjectPtrName(object_pointer_name.c_str());
+            LLDB_LOGF(log,
+                      "Setting object pointer name: %s on function "
+                      "object %p.",
+                      object_pointer_name.c_str(),
+                      static_cast<void *>(function_decl));
           }
+          m_ast.SetMetadata(function_decl, metadata);
         }
       }
     }
-    type_sp = std::make_shared<Type>(
-        die.GetID(), dwarf, attrs.name, llvm::None, nullptr, LLDB_INVALID_UID,
-        Type::eEncodingIsUID, &attrs.decl, clang_type, Type::eResolveStateFull);
-    assert(type_sp.get());
-  } break;
+  }
+  return std::make_shared<Type>(
+      die.GetID(), dwarf, attrs.name, llvm::None, nullptr, LLDB_INVALID_UID,
+      Type::eEncodingIsUID, &attrs.decl, clang_type, Type::ResolveState::Full);
+}
 
-  case DW_TAG_array_type: {
-    DEBUG_PRINTF("0x%8.8" PRIx64 ": %s (\"%s\")\n", die.GetID(),
-                 DW_TAG_value_to_name(tag), type_name_cstr);
+TypeSP DWARFASTParserClang::ParseArrayType(const DWARFDIE &die,
+                                           ParsedDWARFTypeAttributes &attrs) {
+  SymbolFileDWARF *dwarf = die.GetDWARF();
 
-    DWARFDIE type_die = attrs.type.Reference();
-    Type *element_type = dwarf->ResolveTypeUID(type_die, true);
+  DEBUG_PRINTF("0x%8.8" PRIx64 ": %s (\"%s\")\n", die.GetID(),
+               DW_TAG_value_to_name(tag), type_name_cstr);
 
-    if (element_type) {
-      auto array_info = ParseChildArrayInfo(die);
-      if (array_info) {
-        attrs.byte_stride = array_info->byte_stride;
-        attrs.bit_stride = array_info->bit_stride;
-      }
-      if (attrs.byte_stride == 0 && attrs.bit_stride == 0)
-        attrs.byte_stride = element_type->GetByteSize().getValueOr(0);
-      CompilerType array_element_type = element_type->GetForwardCompilerType();
-
-      if (ClangASTContext::IsCXXClassType(array_element_type) &&
-          !array_element_type.GetCompleteType()) {
-        ModuleSP module_sp = die.GetModule();
-        if (module_sp) {
-          if (die.GetCU()->GetProducer() == eProducerClang)
-            module_sp->ReportError(
-                "DWARF DW_TAG_array_type DIE at 0x%8.8x has a "
-                "class/union/struct element type DIE 0x%8.8x that is a "
-                "forward declaration, not a complete definition.\nTry "
-                "compiling the source file with -fstandalone-debug or "
-                "disable -gmodules",
-                die.GetOffset(), type_die.GetOffset());
-          else
-            module_sp->ReportError(
-                "DWARF DW_TAG_array_type DIE at 0x%8.8x has a "
-                "class/union/struct element type DIE 0x%8.8x that is a "
-                "forward declaration, not a complete definition.\nPlease "
-                "file a bug against the compiler and include the "
-                "preprocessed output for %s",
-                die.GetOffset(), type_die.GetOffset(),
-                GetUnitName(die).c_str());
-        }
+  DWARFDIE type_die = attrs.type.Reference();
+  Type *element_type = dwarf->ResolveTypeUID(type_die, true);
 
-        // We have no choice other than to pretend that the element class
-        // type is complete. If we don't do this, clang will crash when
-        // trying to layout the class. Since we provide layout
-        // assistance, all ivars in this class and other classes will be
-        // fine, this is the best we can do short of crashing.
-        if (ClangASTContext::StartTagDeclarationDefinition(
-                array_element_type)) {
-          ClangASTContext::CompleteTagDeclarationDefinition(array_element_type);
-        } else {
-          module_sp->ReportError("DWARF DIE at 0x%8.8x was not able to "
-                                 "start its definition.\nPlease file a "
-                                 "bug and attach the file at the start "
-                                 "of this error message",
-                                 type_die.GetOffset());
-        }
-      }
+  if (!element_type)
+    return nullptr;
 
-      uint64_t array_element_bit_stride =
-          attrs.byte_stride * 8 + attrs.bit_stride;
-      if (array_info && array_info->element_orders.size() > 0) {
-        uint64_t num_elements = 0;
-        auto end = array_info->element_orders.rend();
-        for (auto pos = array_info->element_orders.rbegin(); pos != end;
-             ++pos) {
-          num_elements = *pos;
-          clang_type = m_ast.CreateArrayType(array_element_type, num_elements,
-                                             attrs.is_vector);
-          array_element_type = clang_type;
-          array_element_bit_stride =
-              num_elements ? array_element_bit_stride * num_elements
-                           : array_element_bit_stride;
-        }
-      } else {
-        clang_type = m_ast.CreateArrayType(array_element_type, 0, attrs.is_vector);
-      }
-      ConstString empty_name;
-      type_sp = std::make_shared<Type>(
-          die.GetID(), dwarf, empty_name, array_element_bit_stride / 8, nullptr,
-          dwarf->GetUID(type_die), Type::eEncodingIsUID, &attrs.decl,
-          clang_type, Type::eResolveStateFull);
-      type_sp->SetEncodingType(element_type);
-      m_ast.SetMetadataAsUserID(clang_type.GetOpaqueQualType(), die.GetID());
+  llvm::Optional<SymbolFile::ArrayInfo> array_info = ParseChildArrayInfo(die);
+  if (array_info) {
+    attrs.byte_stride = array_info->byte_stride;
+    attrs.bit_stride = array_info->bit_stride;
+  }
+  if (attrs.byte_stride == 0 && attrs.bit_stride == 0)
+    attrs.byte_stride = element_type->GetByteSize().getValueOr(0);
+  CompilerType array_element_type = element_type->GetForwardCompilerType();
+
+  if (ClangASTContext::IsCXXClassType(array_element_type) &&
+      !array_element_type.GetCompleteType()) {
+    ModuleSP module_sp = die.GetModule();
+    if (module_sp) {
+      if (die.GetCU()->GetProducer() == eProducerClang)
+        module_sp->ReportError(
+            "DWARF DW_TAG_array_type DIE at 0x%8.8x has a "
+            "class/union/struct element type DIE 0x%8.8x that is a "
+            "forward declaration, not a complete definition.\nTry "
+            "compiling the source file with -fstandalone-debug or "
+            "disable -gmodules",
+            die.GetOffset(), type_die.GetOffset());
+      else
+        module_sp->ReportError(
+            "DWARF DW_TAG_array_type DIE at 0x%8.8x has a "
+            "class/union/struct element type DIE 0x%8.8x that is a "
+            "forward declaration, not a complete definition.\nPlease "
+            "file a bug against the compiler and include the "
+            "preprocessed output for %s",
+            die.GetOffset(), type_die.GetOffset(), GetUnitName(die).c_str());
+    }
+
+    // We have no choice other than to pretend that the element class
+    // type is complete. If we don't do this, clang will crash when
+    // trying to layout the class. Since we provide layout
+    // assistance, all ivars in this class and other classes will be
+    // fine, this is the best we can do short of crashing.
+    if (ClangASTContext::StartTagDeclarationDefinition(array_element_type)) {
+      ClangASTContext::CompleteTagDeclarationDefinition(array_element_type);
+    } else {
+      module_sp->ReportError("DWARF DIE at 0x%8.8x was not able to "
+                             "start its definition.\nPlease file a "
+                             "bug and attach the file at the start "
+                             "of this error message",
+                             type_die.GetOffset());
     }
-  } break;
+  }
 
-  case DW_TAG_ptr_to_member_type: {
-    Type *pointee_type = dwarf->ResolveTypeUID(attrs.type.Reference(), true);
-    Type *class_type =
-        dwarf->ResolveTypeUID(attrs.containing_type.Reference(), true);
+  uint64_t array_element_bit_stride =
+      attrs.byte_stride * 8 + attrs.bit_stride;
+  CompilerType clang_type;
+  if (array_info && array_info->element_orders.size() > 0) {
+    uint64_t num_elements = 0;
+    auto end = array_info->element_orders.rend();
+    for (auto pos = array_info->element_orders.rbegin(); pos != end; ++pos) {
+      num_elements = *pos;
+      clang_type = m_ast.CreateArrayType(array_element_type, num_elements,
+                                         attrs.is_vector);
+      array_element_type = clang_type;
+      array_element_bit_stride = num_elements
+                                     ? array_element_bit_stride * num_elements
+                                     : array_element_bit_stride;
+    }
+  } else {
+    clang_type =
+        m_ast.CreateArrayType(array_element_type, 0, attrs.is_vector);
+  }
+  ConstString empty_name;
+  TypeSP type_sp = std::make_shared<Type>(
+      die.GetID(), dwarf, empty_name, array_element_bit_stride / 8, nullptr,
+      dwarf->GetUID(type_die), Type::eEncodingIsUID, &attrs.decl, clang_type,
+      Type::ResolveState::Full);
+  type_sp->SetEncodingType(element_type);
+  const clang::Type *type = ClangUtil::GetQualType(clang_type).getTypePtr();
+  m_ast.SetMetadataAsUserID(type, die.GetID());
+  return type_sp;
+}
 
-    CompilerType pointee_clang_type = pointee_type->GetForwardCompilerType();
-    CompilerType class_clang_type = class_type->GetLayoutCompilerType();
+TypeSP DWARFASTParserClang::ParsePointerToMemberType(
+    const DWARFDIE &die, const ParsedDWARFTypeAttributes &attrs) {
+  SymbolFileDWARF *dwarf = die.GetDWARF();
+  Type *pointee_type = dwarf->ResolveTypeUID(attrs.type.Reference(), true);
+  Type *class_type =
+      dwarf->ResolveTypeUID(attrs.containing_type.Reference(), true);
 
-    clang_type = ClangASTContext::CreateMemberPointerType(class_clang_type,
-                                                          pointee_clang_type);
+  CompilerType pointee_clang_type = pointee_type->GetForwardCompilerType();
+  CompilerType class_clang_type = class_type->GetLayoutCompilerType();
 
-    if (llvm::Optional<uint64_t> clang_type_size =
-            clang_type.GetByteSize(nullptr)) {
-      type_sp = std::make_shared<Type>(
-          die.GetID(), dwarf, attrs.name, *clang_type_size, nullptr,
-          LLDB_INVALID_UID, Type::eEncodingIsUID, nullptr, clang_type,
-          Type::eResolveStateForward);
-    }
+  CompilerType clang_type = ClangASTContext::CreateMemberPointerType(
+      class_clang_type, pointee_clang_type);
 
-    break;
-  }
-  default:
-    dwarf->GetObjectFile()->GetModule()->ReportError(
-        "{0x%8.8x}: unhandled type tag 0x%4.4x (%s), please file a bug and "
-        "attach the file at the start of this error message",
-        die.GetOffset(), tag, DW_TAG_value_to_name(tag));
-    break;
+  if (llvm::Optional<uint64_t> clang_type_size =
+          clang_type.GetByteSize(nullptr)) {
+    return std::make_shared<Type>(die.GetID(), dwarf, attrs.name,
+                                  *clang_type_size, nullptr, LLDB_INVALID_UID,
+                                  Type::eEncodingIsUID, nullptr, clang_type,
+                                  Type::ResolveState::Forward);
   }
-
-  // TODO: We should consider making the switch above exhaustive to simplify
-  // control flow in ParseTypeFromDWARF. Then, we could simply replace this
-  // return statement with a call to llvm_unreachable.
-  return UpdateSymbolContextScopeForType(sc, die, type_sp);
+  return nullptr;
 }
 
 TypeSP DWARFASTParserClang::UpdateSymbolContextScopeForType(
@@ -1281,20 +1380,20 @@ TypeSP DWARFASTParserClang::UpdateSymbolContextScopeForType(
   DWARFDIE sc_parent_die = SymbolFileDWARF::GetParentSymbolContextDIE(die);
   dw_tag_t sc_parent_tag = sc_parent_die.Tag();
 
-  SymbolContextScope *symbol_context_scope = NULL;
+  SymbolContextScope *symbol_context_scope = nullptr;
   if (sc_parent_tag == DW_TAG_compile_unit ||
       sc_parent_tag == DW_TAG_partial_unit) {
     symbol_context_scope = sc.comp_unit;
-  } else if (sc.function != NULL && sc_parent_die) {
+  } else if (sc.function != nullptr && sc_parent_die) {
     symbol_context_scope =
         sc.function->GetBlock(true).FindBlockByID(sc_parent_die.GetID());
-    if (symbol_context_scope == NULL)
+    if (symbol_context_scope == nullptr)
       symbol_context_scope = sc.function;
   } else {
     symbol_context_scope = sc.module_sp.get();
   }
 
-  if (symbol_context_scope != NULL)
+  if (symbol_context_scope != nullptr)
     type_sp->SetSymbolContextScope(symbol_context_scope);
 
   // We are ready to put this type into the uniqued list up at the module
@@ -1306,7 +1405,8 @@ TypeSP DWARFASTParserClang::UpdateSymbolContextScopeForType(
 }
 
 TypeSP
-DWARFASTParserClang::ParseStructureLikeDIE(const DWARFDIE &die,
+DWARFASTParserClang::ParseStructureLikeDIE(const SymbolContext &sc,
+                                           const DWARFDIE &die,
                                            ParsedDWARFTypeAttributes &attrs) {
   TypeSP type_sp;
   CompilerType clang_type;
@@ -1438,9 +1538,9 @@ DWARFASTParserClang::ParseStructureLikeDIE(const DWARFDIE &die,
           attrs.name.GetCString());
     }
 
-    // See if the type comes from a DWO module and if so, track down that
-    // type.
-    type_sp = ParseTypeFromDWO(die, log);
+    // See if the type comes from a Clang module and if so, track down
+    // that type.
+    type_sp = ParseTypeFromClangModule(sc, die, log);
     if (type_sp)
       return type_sp;
 
@@ -1495,7 +1595,7 @@ DWARFASTParserClang::ParseStructureLikeDIE(const DWARFDIE &die,
     // backing the Decl is complete before adding children to it. This is
     // not an issue in the non-gmodules case because the debug info will
     // always contain a full definition of parent types in that case.
-    CompleteExternalTagDeclType(GetClangASTImporter(), decl_ctx, die,
+    CompleteExternalTagDeclType(m_ast, GetClangASTImporter(), decl_ctx, die,
                                 attrs.name.GetCString());
 
     if (attrs.accessibility == eAccessNone && decl_ctx) {
@@ -1546,7 +1646,7 @@ DWARFASTParserClang::ParseStructureLikeDIE(const DWARFDIE &die,
       clang_type_was_created = true;
       clang_type = m_ast.CreateRecordType(
           decl_ctx, attrs.accessibility, attrs.name.GetCString(), tag_decl_kind,
-          attrs.class_language, &metadata);
+          attrs.class_language, &metadata, attrs.exports_symbols);
     }
   }
 
@@ -1557,7 +1657,7 @@ DWARFASTParserClang::ParseStructureLikeDIE(const DWARFDIE &die,
   type_sp = std::make_shared<Type>(die.GetID(), dwarf, attrs.name,
                                    attrs.byte_size, nullptr, LLDB_INVALID_UID,
                                    Type::eEncodingIsUID, &attrs.decl,
-                                   clang_type, Type::eResolveStateForward);
+                                   clang_type, Type::ResolveState::Forward);
 
   type_sp->SetIsCompleteObjCClass(attrs.is_complete_objc_class);
 
@@ -1621,7 +1721,7 @@ DWARFASTParserClang::ParseStructureLikeDIE(const DWARFDIE &die,
             ClangASTContext::GetAsRecordDecl(clang_type);
 
         if (record_decl) {
-          GetClangASTImporter().InsertRecordDecl(
+          GetClangASTImporter().SetRecordLayout(
               record_decl, ClangASTImporter::LayoutInfo());
         }
       }
@@ -1810,7 +1910,7 @@ bool DWARFASTParserClang::ParseTemplateDIE(
         }
       }
 
-      clang::ASTContext *ast = m_ast.getASTContext();
+      clang::ASTContext &ast = m_ast.getASTContext();
       if (!clang_type)
         clang_type = m_ast.GetBasicType(eBasicTypeVoid);
 
@@ -1830,7 +1930,7 @@ bool DWARFASTParserClang::ParseTemplateDIE(
             return false;
           llvm::APInt apint(*size, uval64, is_signed);
           template_param_infos.args.push_back(
-              clang::TemplateArgument(*ast, llvm::APSInt(apint, !is_signed),
+              clang::TemplateArgument(ast, llvm::APSInt(apint, !is_signed),
                                       ClangUtil::GetQualType(clang_type)));
         } else {
           template_param_infos.args.push_back(
@@ -1880,6 +1980,182 @@ bool DWARFASTParserClang::ParseTemplateParameterInfos(
   return template_param_infos.args.size() == template_param_infos.names.size();
 }
 
+bool DWARFASTParserClang::CompleteRecordType(const DWARFDIE &die,
+                                             lldb_private::Type *type,
+                                             CompilerType &clang_type) {
+  const dw_tag_t tag = die.Tag();
+  SymbolFileDWARF *dwarf = die.GetDWARF();
+
+  ClangASTImporter::LayoutInfo layout_info;
+
+  {
+    if (die.HasChildren()) {
+      LanguageType class_language = eLanguageTypeUnknown;
+      if (ClangASTContext::IsObjCObjectOrInterfaceType(clang_type)) {
+        class_language = eLanguageTypeObjC;
+        // For objective C we don't start the definition when the class is
+        // created.
+        ClangASTContext::StartTagDeclarationDefinition(clang_type);
+      }
+
+      int tag_decl_kind = -1;
+      AccessType default_accessibility = eAccessNone;
+      if (tag == DW_TAG_structure_type) {
+        tag_decl_kind = clang::TTK_Struct;
+        default_accessibility = eAccessPublic;
+      } else if (tag == DW_TAG_union_type) {
+        tag_decl_kind = clang::TTK_Union;
+        default_accessibility = eAccessPublic;
+      } else if (tag == DW_TAG_class_type) {
+        tag_decl_kind = clang::TTK_Class;
+        default_accessibility = eAccessPrivate;
+      }
+
+      std::vector<std::unique_ptr<clang::CXXBaseSpecifier>> bases;
+      std::vector<int> member_accessibilities;
+      bool is_a_class = false;
+      // Parse members and base classes first
+      std::vector<DWARFDIE> member_function_dies;
+
+      DelayedPropertyList delayed_properties;
+      ParseChildMembers(die, clang_type, class_language, bases,
+                        member_accessibilities, member_function_dies,
+                        delayed_properties, default_accessibility, is_a_class,
+                        layout_info);
+
+      // Now parse any methods if there were any...
+      for (const DWARFDIE &die : member_function_dies)
+        dwarf->ResolveType(die);
+
+      if (class_language == eLanguageTypeObjC) {
+        ConstString class_name(clang_type.GetTypeName());
+        if (class_name) {
+          DIEArray method_die_offsets;
+          dwarf->GetObjCMethodDIEOffsets(class_name, method_die_offsets);
+
+          if (!method_die_offsets.empty()) {
+            DWARFDebugInfo *debug_info = dwarf->DebugInfo();
+
+            const size_t num_matches = method_die_offsets.size();
+            for (size_t i = 0; i < num_matches; ++i) {
+              const DIERef &die_ref = method_die_offsets[i];
+              DWARFDIE method_die = debug_info->GetDIE(die_ref);
+
+              if (method_die)
+                method_die.ResolveType();
+            }
+          }
+
+          for (DelayedPropertyList::iterator pi = delayed_properties.begin(),
+                                             pe = delayed_properties.end();
+               pi != pe; ++pi)
+            pi->Finalize();
+        }
+      }
+
+      // If we have a DW_TAG_structure_type instead of a DW_TAG_class_type we
+      // need to tell the clang type it is actually a class.
+      if (class_language != eLanguageTypeObjC) {
+        if (is_a_class && tag_decl_kind != clang::TTK_Class)
+          m_ast.SetTagTypeKind(ClangUtil::GetQualType(clang_type),
+                               clang::TTK_Class);
+      }
+
+      // Since DW_TAG_structure_type gets used for both classes and
+      // structures, we may need to set any DW_TAG_member fields to have a
+      // "private" access if none was specified. When we parsed the child
+      // members we tracked that actual accessibility value for each
+      // DW_TAG_member in the "member_accessibilities" array. If the value
+      // for the member is zero, then it was set to the
+      // "default_accessibility" which for structs was "public". Below we
+      // correct this by setting any fields to "private" that weren't
+      // correctly set.
+      if (is_a_class && !member_accessibilities.empty()) {
+        // This is a class and all members that didn't have their access
+        // specified are private.
+        m_ast.SetDefaultAccessForRecordFields(
+            m_ast.GetAsRecordDecl(clang_type), eAccessPrivate,
+            &member_accessibilities.front(), member_accessibilities.size());
+      }
+
+      if (!bases.empty()) {
+        // Make sure all base classes refer to complete types and not forward
+        // declarations. If we don't do this, clang will crash with an
+        // assertion in the call to clang_type.TransferBaseClasses()
+        for (const auto &base_class : bases) {
+          clang::TypeSourceInfo *type_source_info =
+              base_class->getTypeSourceInfo();
+          if (type_source_info) {
+            CompilerType base_class_type =
+                m_ast.GetType(type_source_info->getType());
+            if (!base_class_type.GetCompleteType()) {
+              auto module = dwarf->GetObjectFile()->GetModule();
+              module->ReportError(":: Class '%s' has a base class '%s' which "
+                                  "does not have a complete definition.",
+                                  die.GetName(),
+                                  base_class_type.GetTypeName().GetCString());
+              if (die.GetCU()->GetProducer() == eProducerClang)
+                module->ReportError(":: Try compiling the source file with "
+                                    "-fstandalone-debug.");
+
+              // We have no choice other than to pretend that the base class
+              // is complete. If we don't do this, clang will crash when we
+              // call setBases() inside of
+              // "clang_type.TransferBaseClasses()" below. Since we
+              // provide layout assistance, all ivars in this class and other
+              // classes will be fine, this is the best we can do short of
+              // crashing.
+              if (ClangASTContext::StartTagDeclarationDefinition(
+                      base_class_type)) {
+                ClangASTContext::CompleteTagDeclarationDefinition(
+                    base_class_type);
+              }
+            }
+          }
+        }
+
+        m_ast.TransferBaseClasses(clang_type.GetOpaqueQualType(),
+                                  std::move(bases));
+      }
+    }
+  }
+
+  m_ast.AddMethodOverridesForCXXRecordType(clang_type.GetOpaqueQualType());
+  ClangASTContext::BuildIndirectFields(clang_type);
+  ClangASTContext::CompleteTagDeclarationDefinition(clang_type);
+
+  if (!layout_info.field_offsets.empty() || !layout_info.base_offsets.empty() ||
+      !layout_info.vbase_offsets.empty()) {
+    if (type)
+      layout_info.bit_size = type->GetByteSize().getValueOr(0) * 8;
+    if (layout_info.bit_size == 0)
+      layout_info.bit_size =
+          die.GetAttributeValueAsUnsigned(DW_AT_byte_size, 0) * 8;
+
+    clang::CXXRecordDecl *record_decl =
+        m_ast.GetAsCXXRecordDecl(clang_type.GetOpaqueQualType());
+    if (record_decl)
+      GetClangASTImporter().SetRecordLayout(record_decl, layout_info);
+  }
+
+  return (bool)clang_type;
+}
+
+bool DWARFASTParserClang::CompleteEnumType(const DWARFDIE &die,
+                                           lldb_private::Type *type,
+                                           CompilerType &clang_type) {
+  if (ClangASTContext::StartTagDeclarationDefinition(clang_type)) {
+    if (die.HasChildren()) {
+      bool is_signed = false;
+      clang_type.IsIntegerType(is_signed);
+      ParseChildEnumerators(clang_type, is_signed,
+                            type->GetByteSize().getValueOr(0), die);
+    }
+    ClangASTContext::CompleteTagDeclarationDefinition(clang_type);
+  }
+  return (bool)clang_type;
+}
+
 bool DWARFASTParserClang::CompleteTypeFromDWARF(const DWARFDIE &die,
                                                 lldb_private::Type *type,
                                                 CompilerType &clang_type) {
@@ -1895,39 +2171,6 @@ bool DWARFASTParserClang::CompleteTypeFromDWARF(const DWARFDIE &die,
   if (!die)
     return false;
 
-#if defined LLDB_CONFIGURATION_DEBUG
-  // For debugging purposes, the LLDB_DWARF_DONT_COMPLETE_TYPENAMES environment
-  // variable can be set with one or more typenames separated by ';'
-  // characters. This will cause this function to not complete any types whose
-  // names match.
-  //
-  // Examples of setting this environment variable:
-  //
-  // LLDB_DWARF_DONT_COMPLETE_TYPENAMES=Foo
-  // LLDB_DWARF_DONT_COMPLETE_TYPENAMES=Foo;Bar;Baz
-  const char *dont_complete_typenames_cstr =
-      getenv("LLDB_DWARF_DONT_COMPLETE_TYPENAMES");
-  if (dont_complete_typenames_cstr && dont_complete_typenames_cstr[0]) {
-    const char *die_name = die.GetName();
-    if (die_name && die_name[0]) {
-      const char *match = strstr(dont_complete_typenames_cstr, die_name);
-      if (match) {
-        size_t die_name_length = strlen(die_name);
-        while (match) {
-          const char separator_char = ';';
-          const char next_char = match[die_name_length];
-          if (next_char == '\0' || next_char == separator_char) {
-            if (match == dont_complete_typenames_cstr ||
-                match[-1] == separator_char)
-              return false;
-          }
-          match = strstr(match + 1, die_name);
-        }
-      }
-    }
-  }
-#endif
-
   const dw_tag_t tag = die.Tag();
 
   Log *log =
@@ -1941,239 +2184,10 @@ bool DWARFASTParserClang::CompleteTypeFromDWARF(const DWARFDIE &die,
   switch (tag) {
   case DW_TAG_structure_type:
   case DW_TAG_union_type:
-  case DW_TAG_class_type: {
-    ClangASTImporter::LayoutInfo layout_info;
-
-    {
-      if (die.HasChildren()) {
-        LanguageType class_language = eLanguageTypeUnknown;
-        if (ClangASTContext::IsObjCObjectOrInterfaceType(clang_type)) {
-          class_language = eLanguageTypeObjC;
-          // For objective C we don't start the definition when the class is
-          // created.
-          ClangASTContext::StartTagDeclarationDefinition(clang_type);
-        }
-
-        int tag_decl_kind = -1;
-        AccessType default_accessibility = eAccessNone;
-        if (tag == DW_TAG_structure_type) {
-          tag_decl_kind = clang::TTK_Struct;
-          default_accessibility = eAccessPublic;
-        } else if (tag == DW_TAG_union_type) {
-          tag_decl_kind = clang::TTK_Union;
-          default_accessibility = eAccessPublic;
-        } else if (tag == DW_TAG_class_type) {
-          tag_decl_kind = clang::TTK_Class;
-          default_accessibility = eAccessPrivate;
-        }
-
-        std::vector<std::unique_ptr<clang::CXXBaseSpecifier>> bases;
-        std::vector<int> member_accessibilities;
-        bool is_a_class = false;
-        // Parse members and base classes first
-        std::vector<DWARFDIE> member_function_dies;
-
-        DelayedPropertyList delayed_properties;
-        ParseChildMembers(die, clang_type, class_language, bases,
-                          member_accessibilities, member_function_dies,
-                          delayed_properties, default_accessibility, is_a_class,
-                          layout_info);
-
-        // Now parse any methods if there were any...
-        for (const DWARFDIE &die : member_function_dies)
-          dwarf->ResolveType(die);
-
-        if (class_language == eLanguageTypeObjC) {
-          ConstString class_name(clang_type.GetTypeName());
-          if (class_name) {
-            DIEArray method_die_offsets;
-            dwarf->GetObjCMethodDIEOffsets(class_name, method_die_offsets);
-
-            if (!method_die_offsets.empty()) {
-              DWARFDebugInfo *debug_info = dwarf->DebugInfo();
-
-              const size_t num_matches = method_die_offsets.size();
-              for (size_t i = 0; i < num_matches; ++i) {
-                const DIERef &die_ref = method_die_offsets[i];
-                DWARFDIE method_die = debug_info->GetDIE(die_ref);
-
-                if (method_die)
-                  method_die.ResolveType();
-              }
-            }
-
-            for (DelayedPropertyList::iterator pi = delayed_properties.begin(),
-                                               pe = delayed_properties.end();
-                 pi != pe; ++pi)
-              pi->Finalize();
-          }
-        }
-
-        // If we have a DW_TAG_structure_type instead of a DW_TAG_class_type we
-        // need to tell the clang type it is actually a class.
-        if (class_language != eLanguageTypeObjC) {
-          if (is_a_class && tag_decl_kind != clang::TTK_Class)
-            m_ast.SetTagTypeKind(ClangUtil::GetQualType(clang_type),
-                                 clang::TTK_Class);
-        }
-
-        // Since DW_TAG_structure_type gets used for both classes and
-        // structures, we may need to set any DW_TAG_member fields to have a
-        // "private" access if none was specified. When we parsed the child
-        // members we tracked that actual accessibility value for each
-        // DW_TAG_member in the "member_accessibilities" array. If the value
-        // for the member is zero, then it was set to the
-        // "default_accessibility" which for structs was "public". Below we
-        // correct this by setting any fields to "private" that weren't
-        // correctly set.
-        if (is_a_class && !member_accessibilities.empty()) {
-          // This is a class and all members that didn't have their access
-          // specified are private.
-          m_ast.SetDefaultAccessForRecordFields(
-              m_ast.GetAsRecordDecl(clang_type), eAccessPrivate,
-              &member_accessibilities.front(), member_accessibilities.size());
-        }
-
-        if (!bases.empty()) {
-          // Make sure all base classes refer to complete types and not forward
-          // declarations. If we don't do this, clang will crash with an
-          // assertion in the call to clang_type.TransferBaseClasses()
-          for (const auto &base_class : bases) {
-            clang::TypeSourceInfo *type_source_info =
-                base_class->getTypeSourceInfo();
-            if (type_source_info) {
-              CompilerType base_class_type(
-                  &m_ast, type_source_info->getType().getAsOpaquePtr());
-              if (!base_class_type.GetCompleteType()) {
-                auto module = dwarf->GetObjectFile()->GetModule();
-                module->ReportError(":: Class '%s' has a base class '%s' which "
-                                    "does not have a complete definition.",
-                                    die.GetName(),
-                                    base_class_type.GetTypeName().GetCString());
-                if (die.GetCU()->GetProducer() == eProducerClang)
-                  module->ReportError(":: Try compiling the source file with "
-                                      "-fstandalone-debug.");
-
-                // We have no choice other than to pretend that the base class
-                // is complete. If we don't do this, clang will crash when we
-                // call setBases() inside of
-                // "clang_type.TransferBaseClasses()" below. Since we
-                // provide layout assistance, all ivars in this class and other
-                // classes will be fine, this is the best we can do short of
-                // crashing.
-                if (ClangASTContext::StartTagDeclarationDefinition(
-                        base_class_type)) {
-                  ClangASTContext::CompleteTagDeclarationDefinition(
-                      base_class_type);
-                }
-              }
-            }
-          }
-
-          m_ast.TransferBaseClasses(clang_type.GetOpaqueQualType(),
-                                    std::move(bases));
-        }
-      }
-    }
-
-    m_ast.AddMethodOverridesForCXXRecordType(clang_type.GetOpaqueQualType());
-    ClangASTContext::BuildIndirectFields(clang_type);
-    ClangASTContext::CompleteTagDeclarationDefinition(clang_type);
-
-    if (!layout_info.field_offsets.empty() ||
-        !layout_info.base_offsets.empty() ||
-        !layout_info.vbase_offsets.empty()) {
-      if (type)
-        layout_info.bit_size = type->GetByteSize().getValueOr(0) * 8;
-      if (layout_info.bit_size == 0)
-        layout_info.bit_size =
-            die.GetAttributeValueAsUnsigned(DW_AT_byte_size, 0) * 8;
-
-      clang::CXXRecordDecl *record_decl =
-          m_ast.GetAsCXXRecordDecl(clang_type.GetOpaqueQualType());
-      if (record_decl) {
-        if (log) {
-          ModuleSP module_sp = dwarf->GetObjectFile()->GetModule();
-
-          if (module_sp) {
-            module_sp->LogMessage(
-                log,
-                "ClangASTContext::CompleteTypeFromDWARF (clang_type = %p) "
-                "caching layout info for record_decl = %p, bit_size = %" PRIu64
-                ", alignment = %" PRIu64
-                ", field_offsets[%u], base_offsets[%u], vbase_offsets[%u])",
-                static_cast<void *>(clang_type.GetOpaqueQualType()),
-                static_cast<void *>(record_decl), layout_info.bit_size,
-                layout_info.alignment,
-                static_cast<uint32_t>(layout_info.field_offsets.size()),
-                static_cast<uint32_t>(layout_info.base_offsets.size()),
-                static_cast<uint32_t>(layout_info.vbase_offsets.size()));
-
-            uint32_t idx;
-            {
-              llvm::DenseMap<const clang::FieldDecl *, uint64_t>::const_iterator
-                  pos,
-                  end = layout_info.field_offsets.end();
-              for (idx = 0, pos = layout_info.field_offsets.begin(); pos != end;
-                   ++pos, ++idx) {
-                module_sp->LogMessage(
-                    log, "ClangASTContext::CompleteTypeFromDWARF (clang_type = "
-                         "%p) field[%u] = { bit_offset=%u, name='%s' }",
-                    static_cast<void *>(clang_type.GetOpaqueQualType()), idx,
-                    static_cast<uint32_t>(pos->second),
-                    pos->first->getNameAsString().c_str());
-              }
-            }
-
-            {
-              llvm::DenseMap<const clang::CXXRecordDecl *,
-                             clang::CharUnits>::const_iterator base_pos,
-                  base_end = layout_info.base_offsets.end();
-              for (idx = 0, base_pos = layout_info.base_offsets.begin();
-                   base_pos != base_end; ++base_pos, ++idx) {
-                module_sp->LogMessage(
-                    log, "ClangASTContext::CompleteTypeFromDWARF (clang_type = "
-                         "%p) base[%u] = { byte_offset=%u, name='%s' }",
-                    clang_type.GetOpaqueQualType(), idx,
-                    (uint32_t)base_pos->second.getQuantity(),
-                    base_pos->first->getNameAsString().c_str());
-              }
-            }
-            {
-              llvm::DenseMap<const clang::CXXRecordDecl *,
-                             clang::CharUnits>::const_iterator vbase_pos,
-                  vbase_end = layout_info.vbase_offsets.end();
-              for (idx = 0, vbase_pos = layout_info.vbase_offsets.begin();
-                   vbase_pos != vbase_end; ++vbase_pos, ++idx) {
-                module_sp->LogMessage(
-                    log, "ClangASTContext::CompleteTypeFromDWARF (clang_type = "
-                         "%p) vbase[%u] = { byte_offset=%u, name='%s' }",
-                    static_cast<void *>(clang_type.GetOpaqueQualType()), idx,
-                    static_cast<uint32_t>(vbase_pos->second.getQuantity()),
-                    vbase_pos->first->getNameAsString().c_str());
-              }
-            }
-          }
-        }
-        GetClangASTImporter().InsertRecordDecl(record_decl, layout_info);
-      }
-    }
-  }
-
-    return (bool)clang_type;
-
+  case DW_TAG_class_type:
+    return CompleteRecordType(die, type, clang_type);
   case DW_TAG_enumeration_type:
-    if (ClangASTContext::StartTagDeclarationDefinition(clang_type)) {
-      if (die.HasChildren()) {
-        bool is_signed = false;
-        clang_type.IsIntegerType(is_signed);
-        ParseChildEnumerators(clang_type, is_signed,
-                              type->GetByteSize().getValueOr(0), die);
-      }
-      ClangASTContext::CompleteTagDeclarationDefinition(clang_type);
-    }
-    return (bool)clang_type;
-
+    return CompleteEnumType(die, type, clang_type);
   default:
     assert(false && "not a forward clang type decl!");
     break;
@@ -2205,7 +2219,7 @@ CompilerDeclContext
 DWARFASTParserClang::GetDeclContextForUIDFromDWARF(const DWARFDIE &die) {
   clang::DeclContext *clang_decl_ctx = GetClangDeclContextForDIE(die);
   if (clang_decl_ctx)
-    return CompilerDeclContext(&m_ast, clang_decl_ctx);
+    return m_ast.CreateDeclContext(clang_decl_ctx);
   return CompilerDeclContext();
 }
 
@@ -2214,7 +2228,7 @@ DWARFASTParserClang::GetDeclContextContainingUIDFromDWARF(const DWARFDIE &die) {
   clang::DeclContext *clang_decl_ctx =
       GetClangDeclContextContainingDIE(die, nullptr);
   if (clang_decl_ctx)
-    return CompilerDeclContext(&m_ast, clang_decl_ctx);
+    return m_ast.CreateDeclContext(clang_decl_ctx);
   return CompilerDeclContext();
 }
 
@@ -2284,54 +2298,6 @@ size_t DWARFASTParserClang::ParseChildEnumerators(
   return enumerators_added;
 }
 
-#if defined(LLDB_CONFIGURATION_DEBUG) || defined(LLDB_CONFIGURATION_RELEASE)
-
-class DIEStack {
-public:
-  void Push(const DWARFDIE &die) { m_dies.push_back(die); }
-
-  void LogDIEs(Log *log) {
-    StreamString log_strm;
-    const size_t n = m_dies.size();
-    log_strm.Printf("DIEStack[%" PRIu64 "]:\n", (uint64_t)n);
-    for (size_t i = 0; i < n; i++) {
-      std::string qualified_name;
-      const DWARFDIE &die = m_dies[i];
-      die.GetQualifiedName(qualified_name);
-      log_strm.Printf("[%" PRIu64 "] 0x%8.8x: %s name='%s'\n", (uint64_t)i,
-                      die.GetOffset(), die.GetTagAsCString(),
-                      qualified_name.c_str());
-    }
-    log->PutCString(log_strm.GetData());
-  }
-  void Pop() { m_dies.pop_back(); }
-
-  class ScopedPopper {
-  public:
-    ScopedPopper(DIEStack &die_stack)
-        : m_die_stack(die_stack), m_valid(false) {}
-
-    void Push(const DWARFDIE &die) {
-      m_valid = true;
-      m_die_stack.Push(die);
-    }
-
-    ~ScopedPopper() {
-      if (m_valid)
-        m_die_stack.Pop();
-    }
-
-  protected:
-    DIEStack &m_die_stack;
-    bool m_valid;
-  };
-
-protected:
-  typedef std::vector<DWARFDIE> Stack;
-  Stack m_dies;
-};
-#endif
-
 Function *DWARFASTParserClang::ParseFunctionFromDWARF(CompileUnit &comp_unit,
                                                       const DWARFDIE &die) {
   DWARFRangeList func_ranges;
@@ -2445,495 +2411,499 @@ Function *DWARFASTParserClang::ParseFunctionFromDWARF(CompileUnit &comp_unit,
   return nullptr;
 }
 
-bool DWARFASTParserClang::ParseChildMembers(
-    const DWARFDIE &parent_die, CompilerType &class_clang_type,
-    const LanguageType class_language,
-    std::vector<std::unique_ptr<clang::CXXBaseSpecifier>> &base_classes,
+void DWARFASTParserClang::ParseSingleMember(
+    const DWARFDIE &die, const DWARFDIE &parent_die,
+    lldb_private::CompilerType &class_clang_type,
+    const lldb::LanguageType class_language,
     std::vector<int> &member_accessibilities,
-    std::vector<DWARFDIE> &member_function_dies,
-    DelayedPropertyList &delayed_properties, AccessType &default_accessibility,
-    bool &is_a_class, ClangASTImporter::LayoutInfo &layout_info) {
-  if (!parent_die)
-    return false;
-
+    lldb::AccessType &default_accessibility,
+    DelayedPropertyList &delayed_properties,
+    lldb_private::ClangASTImporter::LayoutInfo &layout_info,
+    BitfieldInfo &last_field_info) {
+  ModuleSP module_sp = parent_die.GetDWARF()->GetObjectFile()->GetModule();
+  const dw_tag_t tag = die.Tag();
   // Get the parent byte size so we can verify any members will fit
   const uint64_t parent_byte_size =
       parent_die.GetAttributeValueAsUnsigned(DW_AT_byte_size, UINT64_MAX);
   const uint64_t parent_bit_size =
       parent_byte_size == UINT64_MAX ? UINT64_MAX : parent_byte_size * 8;
 
-  uint32_t member_idx = 0;
-  BitfieldInfo last_field_info;
-
-  ModuleSP module_sp = parent_die.GetDWARF()->GetObjectFile()->GetModule();
-  ClangASTContext *ast =
-      llvm::dyn_cast_or_null<ClangASTContext>(class_clang_type.GetTypeSystem());
-  if (ast == nullptr)
-    return false;
-
-  for (DWARFDIE die = parent_die.GetFirstChild(); die.IsValid();
-       die = die.GetSibling()) {
-    dw_tag_t tag = die.Tag();
-
-    switch (tag) {
-    case DW_TAG_member:
-    case DW_TAG_APPLE_property: {
-      DWARFAttributes attributes;
-      const size_t num_attributes = die.GetAttributes(attributes);
-      if (num_attributes > 0) {
-        const char *name = nullptr;
-        const char *prop_name = nullptr;
-        const char *prop_getter_name = nullptr;
-        const char *prop_setter_name = nullptr;
-        uint32_t prop_attributes = 0;
-
-        bool is_artificial = false;
-        DWARFFormValue encoding_form;
-        AccessType accessibility = eAccessNone;
-        uint32_t member_byte_offset =
-            (parent_die.Tag() == DW_TAG_union_type) ? 0 : UINT32_MAX;
-        llvm::Optional<uint64_t> byte_size;
-        int64_t bit_offset = 0;
-        uint64_t data_bit_offset = UINT64_MAX;
-        size_t bit_size = 0;
-        bool is_external =
-            false; // On DW_TAG_members, this means the member is static
-        uint32_t i;
-        for (i = 0; i < num_attributes && !is_artificial; ++i) {
-          const dw_attr_t attr = attributes.AttributeAtIndex(i);
-          DWARFFormValue form_value;
-          if (attributes.ExtractFormValueAtIndex(i, form_value)) {
-            switch (attr) {
-            case DW_AT_name:
-              name = form_value.AsCString();
-              break;
-            case DW_AT_type:
-              encoding_form = form_value;
-              break;
-            case DW_AT_bit_offset:
-              bit_offset = form_value.Signed();
-              break;
-            case DW_AT_bit_size:
-              bit_size = form_value.Unsigned();
-              break;
-            case DW_AT_byte_size:
-              byte_size = form_value.Unsigned();
-              break;
-            case DW_AT_data_bit_offset:
-              data_bit_offset = form_value.Unsigned();
-              break;
-            case DW_AT_data_member_location:
-              if (form_value.BlockData()) {
-                Value initialValue(0);
-                Value memberOffset(0);
-                const DWARFDataExtractor &debug_info_data = die.GetData();
-                uint32_t block_length = form_value.Unsigned();
-                uint32_t block_offset =
-                    form_value.BlockData() - debug_info_data.GetDataStart();
-                if (DWARFExpression::Evaluate(
-                        nullptr, // ExecutionContext *
-                        nullptr, // RegisterContext *
-                        module_sp,
-                        DataExtractor(debug_info_data, block_offset,
-                                      block_length),
-                        die.GetCU(), eRegisterKindDWARF, &initialValue, nullptr,
-                        memberOffset, nullptr)) {
-                  member_byte_offset =
-                      memberOffset.ResolveValue(nullptr).UInt();
-                }
-              } else {
-                // With DWARF 3 and later, if the value is an integer constant,
-                // this form value is the offset in bytes from the beginning of
-                // the containing entity.
-                member_byte_offset = form_value.Unsigned();
-              }
-              break;
-
-            case DW_AT_accessibility:
-              accessibility = DW_ACCESS_to_AccessType(form_value.Unsigned());
-              break;
-            case DW_AT_artificial:
-              is_artificial = form_value.Boolean();
-              break;
-            case DW_AT_APPLE_property_name:
-              prop_name = form_value.AsCString();
-              break;
-            case DW_AT_APPLE_property_getter:
-              prop_getter_name = form_value.AsCString();
-              break;
-            case DW_AT_APPLE_property_setter:
-              prop_setter_name = form_value.AsCString();
-              break;
-            case DW_AT_APPLE_property_attribute:
-              prop_attributes = form_value.Unsigned();
-              break;
-            case DW_AT_external:
-              is_external = form_value.Boolean();
-              break;
-
-            default:
-            case DW_AT_declaration:
-            case DW_AT_description:
-            case DW_AT_mutable:
-            case DW_AT_visibility:
-            case DW_AT_sibling:
-              break;
+  DWARFAttributes attributes;
+  const size_t num_attributes = die.GetAttributes(attributes);
+  if (num_attributes > 0) {
+    const char *name = nullptr;
+    const char *prop_name = nullptr;
+    const char *prop_getter_name = nullptr;
+    const char *prop_setter_name = nullptr;
+    uint32_t prop_attributes = 0;
+
+    bool is_artificial = false;
+    DWARFFormValue encoding_form;
+    AccessType accessibility = eAccessNone;
+    uint32_t member_byte_offset =
+        (parent_die.Tag() == DW_TAG_union_type) ? 0 : UINT32_MAX;
+    llvm::Optional<uint64_t> byte_size;
+    int64_t bit_offset = 0;
+    uint64_t data_bit_offset = UINT64_MAX;
+    size_t bit_size = 0;
+    bool is_external =
+        false; // On DW_TAG_members, this means the member is static
+    uint32_t i;
+    for (i = 0; i < num_attributes && !is_artificial; ++i) {
+      const dw_attr_t attr = attributes.AttributeAtIndex(i);
+      DWARFFormValue form_value;
+      if (attributes.ExtractFormValueAtIndex(i, form_value)) {
+        switch (attr) {
+        case DW_AT_name:
+          name = form_value.AsCString();
+          break;
+        case DW_AT_type:
+          encoding_form = form_value;
+          break;
+        case DW_AT_bit_offset:
+          bit_offset = form_value.Signed();
+          break;
+        case DW_AT_bit_size:
+          bit_size = form_value.Unsigned();
+          break;
+        case DW_AT_byte_size:
+          byte_size = form_value.Unsigned();
+          break;
+        case DW_AT_data_bit_offset:
+          data_bit_offset = form_value.Unsigned();
+          break;
+        case DW_AT_data_member_location:
+          if (form_value.BlockData()) {
+            Value initialValue(0);
+            Value memberOffset(0);
+            const DWARFDataExtractor &debug_info_data = die.GetData();
+            uint32_t block_length = form_value.Unsigned();
+            uint32_t block_offset =
+                form_value.BlockData() - debug_info_data.GetDataStart();
+            if (DWARFExpression::Evaluate(
+                    nullptr, // ExecutionContext *
+                    nullptr, // RegisterContext *
+                    module_sp,
+                    DataExtractor(debug_info_data, block_offset, block_length),
+                    die.GetCU(), eRegisterKindDWARF, &initialValue, nullptr,
+                    memberOffset, nullptr)) {
+              member_byte_offset = memberOffset.ResolveValue(nullptr).UInt();
             }
+          } else {
+            // With DWARF 3 and later, if the value is an integer constant,
+            // this form value is the offset in bytes from the beginning of
+            // the containing entity.
+            member_byte_offset = form_value.Unsigned();
           }
-        }
-
-        if (prop_name) {
-          ConstString fixed_getter;
-          ConstString fixed_setter;
-
-          // Check if the property getter/setter were provided as full names.
-          // We want basenames, so we extract them.
-
-          if (prop_getter_name && prop_getter_name[0] == '-') {
-            ObjCLanguage::MethodName prop_getter_method(prop_getter_name, true);
-            prop_getter_name = prop_getter_method.GetSelector().GetCString();
-          }
+          break;
 
-          if (prop_setter_name && prop_setter_name[0] == '-') {
-            ObjCLanguage::MethodName prop_setter_method(prop_setter_name, true);
-            prop_setter_name = prop_setter_method.GetSelector().GetCString();
-          }
+        case DW_AT_accessibility:
+          accessibility = DW_ACCESS_to_AccessType(form_value.Unsigned());
+          break;
+        case DW_AT_artificial:
+          is_artificial = form_value.Boolean();
+          break;
+        case DW_AT_APPLE_property_name:
+          prop_name = form_value.AsCString();
+          break;
+        case DW_AT_APPLE_property_getter:
+          prop_getter_name = form_value.AsCString();
+          break;
+        case DW_AT_APPLE_property_setter:
+          prop_setter_name = form_value.AsCString();
+          break;
+        case DW_AT_APPLE_property_attribute:
+          prop_attributes = form_value.Unsigned();
+          break;
+        case DW_AT_external:
+          is_external = form_value.Boolean();
+          break;
 
-          // If the names haven't been provided, they need to be filled in.
+        default:
+        case DW_AT_declaration:
+        case DW_AT_description:
+        case DW_AT_mutable:
+        case DW_AT_visibility:
+        case DW_AT_sibling:
+          break;
+        }
+      }
+    }
 
-          if (!prop_getter_name) {
-            prop_getter_name = prop_name;
-          }
-          if (!prop_setter_name && prop_name[0] &&
-              !(prop_attributes & DW_APPLE_PROPERTY_readonly)) {
-            StreamString ss;
+    if (prop_name) {
+      ConstString fixed_setter;
 
-            ss.Printf("set%c%s:", toupper(prop_name[0]), &prop_name[1]);
+      // Check if the property getter/setter were provided as full names.
+      // We want basenames, so we extract them.
 
-            fixed_setter.SetString(ss.GetString());
-            prop_setter_name = fixed_setter.GetCString();
-          }
-        }
+      if (prop_getter_name && prop_getter_name[0] == '-') {
+        ObjCLanguage::MethodName prop_getter_method(prop_getter_name, true);
+        prop_getter_name = prop_getter_method.GetSelector().GetCString();
+      }
 
-        // Clang has a DWARF generation bug where sometimes it represents
-        // fields that are references with bad byte size and bit size/offset
-        // information such as:
-        //
-        //  DW_AT_byte_size( 0x00 )
-        //  DW_AT_bit_size( 0x40 )
-        //  DW_AT_bit_offset( 0xffffffffffffffc0 )
-        //
-        // So check the bit offset to make sure it is sane, and if the values
-        // are not sane, remove them. If we don't do this then we will end up
-        // with a crash if we try to use this type in an expression when clang
-        // becomes unhappy with its recycled debug info.
-
-        if (byte_size.getValueOr(0) == 0 && bit_offset < 0) {
-          bit_size = 0;
-          bit_offset = 0;
-        }
+      if (prop_setter_name && prop_setter_name[0] == '-') {
+        ObjCLanguage::MethodName prop_setter_method(prop_setter_name, true);
+        prop_setter_name = prop_setter_method.GetSelector().GetCString();
+      }
 
-        // FIXME: Make Clang ignore Objective-C accessibility for expressions
-        if (class_language == eLanguageTypeObjC ||
-            class_language == eLanguageTypeObjC_plus_plus)
-          accessibility = eAccessNone;
-
-        // Handle static members
-        if (is_external && member_byte_offset == UINT32_MAX) {
-          Type *var_type = die.ResolveTypeUID(encoding_form.Reference());
-
-          if (var_type) {
-            if (accessibility == eAccessNone)
-              accessibility = eAccessPublic;
-            ClangASTContext::AddVariableToRecordType(
-                class_clang_type, name, var_type->GetLayoutCompilerType(),
-                accessibility);
-          }
-          break;
-        }
+      // If the names haven't been provided, they need to be filled in.
 
-        if (!is_artificial) {
-          Type *member_type = die.ResolveTypeUID(encoding_form.Reference());
-
-          clang::FieldDecl *field_decl = nullptr;
-          if (tag == DW_TAG_member) {
-            if (member_type) {
-              if (accessibility == eAccessNone)
-                accessibility = default_accessibility;
-              member_accessibilities.push_back(accessibility);
-
-              uint64_t field_bit_offset =
-                  (member_byte_offset == UINT32_MAX ? 0
-                                                    : (member_byte_offset * 8));
-              if (bit_size > 0) {
-
-                BitfieldInfo this_field_info;
-                this_field_info.bit_offset = field_bit_offset;
-                this_field_info.bit_size = bit_size;
-
-                /////////////////////////////////////////////////////////////
-                // How to locate a field given the DWARF debug information
-                //
-                // AT_byte_size indicates the size of the word in which the bit
-                // offset must be interpreted.
-                //
-                // AT_data_member_location indicates the byte offset of the
-                // word from the base address of the structure.
-                //
-                // AT_bit_offset indicates how many bits into the word
-                // (according to the host endianness) the low-order bit of the
-                // field starts.  AT_bit_offset can be negative.
-                //
-                // AT_bit_size indicates the size of the field in bits.
-                /////////////////////////////////////////////////////////////
-
-                if (data_bit_offset != UINT64_MAX) {
-                  this_field_info.bit_offset = data_bit_offset;
-                } else {
-                  if (!byte_size)
-                    byte_size = member_type->GetByteSize();
-
-                  ObjectFile *objfile = die.GetDWARF()->GetObjectFile();
-                  if (objfile->GetByteOrder() == eByteOrderLittle) {
-                    this_field_info.bit_offset += byte_size.getValueOr(0) * 8;
-                    this_field_info.bit_offset -= (bit_offset + bit_size);
-                  } else {
-                    this_field_info.bit_offset += bit_offset;
-                  }
-                }
+      if (!prop_getter_name) {
+        prop_getter_name = prop_name;
+      }
+      if (!prop_setter_name && prop_name[0] &&
+          !(prop_attributes & DW_APPLE_PROPERTY_readonly)) {
+        StreamString ss;
 
-                if ((this_field_info.bit_offset >= parent_bit_size) ||
-                    !last_field_info.NextBitfieldOffsetIsValid(
-                        this_field_info.bit_offset)) {
-                  ObjectFile *objfile = die.GetDWARF()->GetObjectFile();
-                  objfile->GetModule()->ReportWarning(
-                      "0x%8.8" PRIx64 ": %s bitfield named \"%s\" has invalid "
-                      "bit offset (0x%8.8" PRIx64
-                      ") member will be ignored. Please file a bug against the "
-                      "compiler and include the preprocessed output for %s\n",
-                      die.GetID(), DW_TAG_value_to_name(tag), name,
-                      this_field_info.bit_offset,
-                      GetUnitName(parent_die).c_str());
-                  this_field_info.Clear();
-                  continue;
-                }
+        ss.Printf("set%c%s:", toupper(prop_name[0]), &prop_name[1]);
 
-                // Update the field bit offset we will report for layout
-                field_bit_offset = this_field_info.bit_offset;
-
-                // If the member to be emitted did not start on a character
-                // boundary and there is empty space between the last field and
-                // this one, then we need to emit an anonymous member filling
-                // up the space up to its start.  There are three cases here:
-                //
-                // 1 If the previous member ended on a character boundary, then
-                // we can emit an
-                //   anonymous member starting at the most recent character
-                //   boundary.
-                //
-                // 2 If the previous member did not end on a character boundary
-                // and the distance
-                //   from the end of the previous member to the current member
-                //   is less than a
-                //   word width, then we can emit an anonymous member starting
-                //   right after the
-                //   previous member and right before this member.
-                //
-                // 3 If the previous member did not end on a character boundary
-                // and the distance
-                //   from the end of the previous member to the current member
-                //   is greater than
-                //   or equal a word width, then we act as in Case 1.
-
-                const uint64_t character_width = 8;
-                const uint64_t word_width = 32;
-
-                // Objective-C has invalid DW_AT_bit_offset values in older
-                // versions of clang, so we have to be careful and only insert
-                // unnamed bitfields if we have a new enough clang.
-                bool detect_unnamed_bitfields = true;
-
-                if (class_language == eLanguageTypeObjC ||
-                    class_language == eLanguageTypeObjC_plus_plus)
-                  detect_unnamed_bitfields =
-                      die.GetCU()->Supports_unnamed_objc_bitfields();
-
-                if (detect_unnamed_bitfields) {
-                  BitfieldInfo anon_field_info;
-
-                  if ((this_field_info.bit_offset % character_width) !=
-                      0) // not char aligned
-                  {
-                    uint64_t last_field_end = 0;
-
-                    if (last_field_info.IsValid())
-                      last_field_end =
-                          last_field_info.bit_offset + last_field_info.bit_size;
-
-                    if (this_field_info.bit_offset != last_field_end) {
-                      if (((last_field_end % character_width) == 0) || // case 1
-                          (this_field_info.bit_offset - last_field_end >=
-                           word_width)) // case 3
-                      {
-                        anon_field_info.bit_size =
-                            this_field_info.bit_offset % character_width;
-                        anon_field_info.bit_offset =
-                            this_field_info.bit_offset -
-                            anon_field_info.bit_size;
-                      } else // case 2
-                      {
-                        anon_field_info.bit_size =
-                            this_field_info.bit_offset - last_field_end;
-                        anon_field_info.bit_offset = last_field_end;
-                      }
-                    }
-                  }
+        fixed_setter.SetString(ss.GetString());
+        prop_setter_name = fixed_setter.GetCString();
+      }
+    }
 
-                  if (anon_field_info.IsValid()) {
-                    clang::FieldDecl *unnamed_bitfield_decl =
-                        ClangASTContext::AddFieldToRecordType(
-                            class_clang_type, llvm::StringRef(),
-                            m_ast.GetBuiltinTypeForEncodingAndBitSize(
-                                eEncodingSint, word_width),
-                            accessibility, anon_field_info.bit_size);
+    // Clang has a DWARF generation bug where sometimes it represents
+    // fields that are references with bad byte size and bit size/offset
+    // information such as:
+    //
+    //  DW_AT_byte_size( 0x00 )
+    //  DW_AT_bit_size( 0x40 )
+    //  DW_AT_bit_offset( 0xffffffffffffffc0 )
+    //
+    // So check the bit offset to make sure it is sane, and if the values
+    // are not sane, remove them. If we don't do this then we will end up
+    // with a crash if we try to use this type in an expression when clang
+    // becomes unhappy with its recycled debug info.
+
+    if (byte_size.getValueOr(0) == 0 && bit_offset < 0) {
+      bit_size = 0;
+      bit_offset = 0;
+    }
+
+    // FIXME: Make Clang ignore Objective-C accessibility for expressions
+    if (class_language == eLanguageTypeObjC ||
+        class_language == eLanguageTypeObjC_plus_plus)
+      accessibility = eAccessNone;
+
+    // Handle static members
+    if (is_external && member_byte_offset == UINT32_MAX) {
+      Type *var_type = die.ResolveTypeUID(encoding_form.Reference());
+
+      if (var_type) {
+        if (accessibility == eAccessNone)
+          accessibility = eAccessPublic;
+        ClangASTContext::AddVariableToRecordType(
+            class_clang_type, name, var_type->GetLayoutCompilerType(),
+            accessibility);
+      }
+      return;
+    }
+
+    if (!is_artificial) {
+      Type *member_type = die.ResolveTypeUID(encoding_form.Reference());
+
+      clang::FieldDecl *field_decl = nullptr;
+      if (tag == DW_TAG_member) {
+        if (member_type) {
+          if (accessibility == eAccessNone)
+            accessibility = default_accessibility;
+          member_accessibilities.push_back(accessibility);
+
+          uint64_t field_bit_offset =
+              (member_byte_offset == UINT32_MAX ? 0 : (member_byte_offset * 8));
+          if (bit_size > 0) {
+
+            BitfieldInfo this_field_info;
+            this_field_info.bit_offset = field_bit_offset;
+            this_field_info.bit_size = bit_size;
+
+            /////////////////////////////////////////////////////////////
+            // How to locate a field given the DWARF debug information
+            //
+            // AT_byte_size indicates the size of the word in which the bit
+            // offset must be interpreted.
+            //
+            // AT_data_member_location indicates the byte offset of the
+            // word from the base address of the structure.
+            //
+            // AT_bit_offset indicates how many bits into the word
+            // (according to the host endianness) the low-order bit of the
+            // field starts.  AT_bit_offset can be negative.
+            //
+            // AT_bit_size indicates the size of the field in bits.
+            /////////////////////////////////////////////////////////////
+
+            if (data_bit_offset != UINT64_MAX) {
+              this_field_info.bit_offset = data_bit_offset;
+            } else {
+              if (!byte_size)
+                byte_size = member_type->GetByteSize();
 
-                    layout_info.field_offsets.insert(std::make_pair(
-                        unnamed_bitfield_decl, anon_field_info.bit_offset));
-                  }
-                }
-                last_field_info = this_field_info;
+              ObjectFile *objfile = die.GetDWARF()->GetObjectFile();
+              if (objfile->GetByteOrder() == eByteOrderLittle) {
+                this_field_info.bit_offset += byte_size.getValueOr(0) * 8;
+                this_field_info.bit_offset -= (bit_offset + bit_size);
               } else {
-                last_field_info.Clear();
+                this_field_info.bit_offset += bit_offset;
               }
+            }
 
-              CompilerType member_clang_type =
-                  member_type->GetLayoutCompilerType();
-              if (!member_clang_type.IsCompleteType())
-                member_clang_type.GetCompleteType();
+            if ((this_field_info.bit_offset >= parent_bit_size) ||
+                !last_field_info.NextBitfieldOffsetIsValid(
+                    this_field_info.bit_offset)) {
+              ObjectFile *objfile = die.GetDWARF()->GetObjectFile();
+              objfile->GetModule()->ReportWarning(
+                  "0x%8.8" PRIx64 ": %s bitfield named \"%s\" has invalid "
+                  "bit offset (0x%8.8" PRIx64
+                  ") member will be ignored. Please file a bug against the "
+                  "compiler and include the preprocessed output for %s\n",
+                  die.GetID(), DW_TAG_value_to_name(tag), name,
+                  this_field_info.bit_offset, GetUnitName(parent_die).c_str());
+              this_field_info.Clear();
+              return;
+            }
 
+            // Update the field bit offset we will report for layout
+            field_bit_offset = this_field_info.bit_offset;
+
+            // If the member to be emitted did not start on a character
+            // boundary and there is empty space between the last field and
+            // this one, then we need to emit an anonymous member filling
+            // up the space up to its start.  There are three cases here:
+            //
+            // 1 If the previous member ended on a character boundary, then
+            // we can emit an
+            //   anonymous member starting at the most recent character
+            //   boundary.
+            //
+            // 2 If the previous member did not end on a character boundary
+            // and the distance
+            //   from the end of the previous member to the current member
+            //   is less than a
+            //   word width, then we can emit an anonymous member starting
+            //   right after the
+            //   previous member and right before this member.
+            //
+            // 3 If the previous member did not end on a character boundary
+            // and the distance
+            //   from the end of the previous member to the current member
+            //   is greater than
+            //   or equal a word width, then we act as in Case 1.
+
+            const uint64_t character_width = 8;
+            const uint64_t word_width = 32;
+
+            // Objective-C has invalid DW_AT_bit_offset values in older
+            // versions of clang, so we have to be careful and only insert
+            // unnamed bitfields if we have a new enough clang.
+            bool detect_unnamed_bitfields = true;
+
+            if (class_language == eLanguageTypeObjC ||
+                class_language == eLanguageTypeObjC_plus_plus)
+              detect_unnamed_bitfields =
+                  die.GetCU()->Supports_unnamed_objc_bitfields();
+
+            if (detect_unnamed_bitfields) {
+              BitfieldInfo anon_field_info;
+
+              if ((this_field_info.bit_offset % character_width) !=
+                  0) // not char aligned
               {
-                // Older versions of clang emit array[0] and array[1] in the
-                // same way (<rdar://problem/12566646>). If the current field
-                // is at the end of the structure, then there is definitely no
-                // room for extra elements and we override the type to
-                // array[0].
-
-                CompilerType member_array_element_type;
-                uint64_t member_array_size;
-                bool member_array_is_incomplete;
-
-                if (member_clang_type.IsArrayType(
-                        &member_array_element_type, &member_array_size,
-                        &member_array_is_incomplete) &&
-                    !member_array_is_incomplete) {
-                  uint64_t parent_byte_size =
-                      parent_die.GetAttributeValueAsUnsigned(DW_AT_byte_size,
-                                                             UINT64_MAX);
-
-                  if (member_byte_offset >= parent_byte_size) {
-                    if (member_array_size != 1 &&
-                        (member_array_size != 0 ||
-                         member_byte_offset > parent_byte_size)) {
-                      module_sp->ReportError(
-                          "0x%8.8" PRIx64
-                          ": DW_TAG_member '%s' refers to type 0x%8.8x"
-                          " which extends beyond the bounds of 0x%8.8" PRIx64,
-                          die.GetID(), name,
-                          encoding_form.Reference().GetOffset(),
-                          parent_die.GetID());
-                    }
+                uint64_t last_field_end = 0;
+
+                if (last_field_info.IsValid())
+                  last_field_end =
+                      last_field_info.bit_offset + last_field_info.bit_size;
 
-                    member_clang_type = m_ast.CreateArrayType(
-                        member_array_element_type, 0, false);
+                if (this_field_info.bit_offset != last_field_end) {
+                  if (((last_field_end % character_width) == 0) || // case 1
+                      (this_field_info.bit_offset - last_field_end >=
+                       word_width)) // case 3
+                  {
+                    anon_field_info.bit_size =
+                        this_field_info.bit_offset % character_width;
+                    anon_field_info.bit_offset =
+                        this_field_info.bit_offset - anon_field_info.bit_size;
+                  } else // case 2
+                  {
+                    anon_field_info.bit_size =
+                        this_field_info.bit_offset - last_field_end;
+                    anon_field_info.bit_offset = last_field_end;
                   }
                 }
               }
 
-              if (ClangASTContext::IsCXXClassType(member_clang_type) &&
-                  !member_clang_type.GetCompleteType()) {
-                if (die.GetCU()->GetProducer() == eProducerClang)
-                  module_sp->ReportError(
-                      "DWARF DIE at 0x%8.8x (class %s) has a member variable "
-                      "0x%8.8x (%s) whose type is a forward declaration, not a "
-                      "complete definition.\nTry compiling the source file "
-                      "with -fstandalone-debug",
-                      parent_die.GetOffset(), parent_die.GetName(),
-                      die.GetOffset(), name);
-                else
-                  module_sp->ReportError(
-                      "DWARF DIE at 0x%8.8x (class %s) has a member variable "
-                      "0x%8.8x (%s) whose type is a forward declaration, not a "
-                      "complete definition.\nPlease file a bug against the "
-                      "compiler and include the preprocessed output for %s",
-                      parent_die.GetOffset(), parent_die.GetName(),
-                      die.GetOffset(), name, GetUnitName(parent_die).c_str());
-                // We have no choice other than to pretend that the member
-                // class is complete. If we don't do this, clang will crash
-                // when trying to layout the class. Since we provide layout
-                // assistance, all ivars in this class and other classes will
-                // be fine, this is the best we can do short of crashing.
-                if (ClangASTContext::StartTagDeclarationDefinition(
-                        member_clang_type)) {
-                  ClangASTContext::CompleteTagDeclarationDefinition(
-                      member_clang_type);
-                } else {
-                  module_sp->ReportError(
-                      "DWARF DIE at 0x%8.8x (class %s) has a member variable "
-                      "0x%8.8x (%s) whose type claims to be a C++ class but we "
-                      "were not able to start its definition.\nPlease file a "
-                      "bug and attach the file at the start of this error "
-                      "message",
-                      parent_die.GetOffset(), parent_die.GetName(),
-                      die.GetOffset(), name);
-                }
+              if (anon_field_info.IsValid()) {
+                clang::FieldDecl *unnamed_bitfield_decl =
+                    ClangASTContext::AddFieldToRecordType(
+                        class_clang_type, llvm::StringRef(),
+                        m_ast.GetBuiltinTypeForEncodingAndBitSize(eEncodingSint,
+                                                                  word_width),
+                        accessibility, anon_field_info.bit_size);
+
+                layout_info.field_offsets.insert(std::make_pair(
+                    unnamed_bitfield_decl, anon_field_info.bit_offset));
               }
+            }
+            last_field_info = this_field_info;
+          } else {
+            last_field_info.Clear();
+          }
 
-              field_decl = ClangASTContext::AddFieldToRecordType(
-                  class_clang_type, name, member_clang_type, accessibility,
-                  bit_size);
+          CompilerType member_clang_type = member_type->GetLayoutCompilerType();
+          if (!member_clang_type.IsCompleteType())
+            member_clang_type.GetCompleteType();
+
+          {
+            // Older versions of clang emit array[0] and array[1] in the
+            // same way (<rdar://problem/12566646>). If the current field
+            // is at the end of the structure, then there is definitely no
+            // room for extra elements and we override the type to
+            // array[0].
+
+            CompilerType member_array_element_type;
+            uint64_t member_array_size;
+            bool member_array_is_incomplete;
+
+            if (member_clang_type.IsArrayType(&member_array_element_type,
+                                              &member_array_size,
+                                              &member_array_is_incomplete) &&
+                !member_array_is_incomplete) {
+              uint64_t parent_byte_size =
+                  parent_die.GetAttributeValueAsUnsigned(DW_AT_byte_size,
+                                                         UINT64_MAX);
+
+              if (member_byte_offset >= parent_byte_size) {
+                if (member_array_size != 1 &&
+                    (member_array_size != 0 ||
+                     member_byte_offset > parent_byte_size)) {
+                  module_sp->ReportError(
+                      "0x%8.8" PRIx64
+                      ": DW_TAG_member '%s' refers to type 0x%8.8x"
+                      " which extends beyond the bounds of 0x%8.8" PRIx64,
+                      die.GetID(), name, encoding_form.Reference().GetOffset(),
+                      parent_die.GetID());
+                }
 
-              m_ast.SetMetadataAsUserID(field_decl, die.GetID());
+                member_clang_type =
+                    m_ast.CreateArrayType(member_array_element_type, 0, false);
+              }
+            }
+          }
 
-              layout_info.field_offsets.insert(
-                  std::make_pair(field_decl, field_bit_offset));
+          if (ClangASTContext::IsCXXClassType(member_clang_type) &&
+              !member_clang_type.GetCompleteType()) {
+            if (die.GetCU()->GetProducer() == eProducerClang)
+              module_sp->ReportError(
+                  "DWARF DIE at 0x%8.8x (class %s) has a member variable "
+                  "0x%8.8x (%s) whose type is a forward declaration, not a "
+                  "complete definition.\nTry compiling the source file "
+                  "with -fstandalone-debug",
+                  parent_die.GetOffset(), parent_die.GetName(), die.GetOffset(),
+                  name);
+            else
+              module_sp->ReportError(
+                  "DWARF DIE at 0x%8.8x (class %s) has a member variable "
+                  "0x%8.8x (%s) whose type is a forward declaration, not a "
+                  "complete definition.\nPlease file a bug against the "
+                  "compiler and include the preprocessed output for %s",
+                  parent_die.GetOffset(), parent_die.GetName(), die.GetOffset(),
+                  name, GetUnitName(parent_die).c_str());
+            // We have no choice other than to pretend that the member
+            // class is complete. If we don't do this, clang will crash
+            // when trying to layout the class. Since we provide layout
+            // assistance, all ivars in this class and other classes will
+            // be fine, this is the best we can do short of crashing.
+            if (ClangASTContext::StartTagDeclarationDefinition(
+                    member_clang_type)) {
+              ClangASTContext::CompleteTagDeclarationDefinition(
+                  member_clang_type);
             } else {
-              if (name)
-                module_sp->ReportError(
-                    "0x%8.8" PRIx64
-                    ": DW_TAG_member '%s' refers to type 0x%8.8x"
-                    " which was unable to be parsed",
-                    die.GetID(), name, encoding_form.Reference().GetOffset());
-              else
-                module_sp->ReportError(
-                    "0x%8.8" PRIx64 ": DW_TAG_member refers to type 0x%8.8x"
-                    " which was unable to be parsed",
-                    die.GetID(), encoding_form.Reference().GetOffset());
+              module_sp->ReportError(
+                  "DWARF DIE at 0x%8.8x (class %s) has a member variable "
+                  "0x%8.8x (%s) whose type claims to be a C++ class but we "
+                  "were not able to start its definition.\nPlease file a "
+                  "bug and attach the file at the start of this error "
+                  "message",
+                  parent_die.GetOffset(), parent_die.GetName(), die.GetOffset(),
+                  name);
             }
           }
 
-          if (prop_name != nullptr && member_type) {
-            clang::ObjCIvarDecl *ivar_decl = nullptr;
+          field_decl = ClangASTContext::AddFieldToRecordType(
+              class_clang_type, name, member_clang_type, accessibility,
+              bit_size);
 
-            if (field_decl) {
-              ivar_decl = clang::dyn_cast<clang::ObjCIvarDecl>(field_decl);
-              assert(ivar_decl != nullptr);
-            }
+          m_ast.SetMetadataAsUserID(field_decl, die.GetID());
 
-            ClangASTMetadata metadata;
-            metadata.SetUserID(die.GetID());
-            delayed_properties.push_back(DelayedAddObjCClassProperty(
-                class_clang_type, prop_name,
-                member_type->GetLayoutCompilerType(), ivar_decl,
-                prop_setter_name, prop_getter_name, prop_attributes,
-                &metadata));
+          layout_info.field_offsets.insert(
+              std::make_pair(field_decl, field_bit_offset));
+        } else {
+          if (name)
+            module_sp->ReportError(
+                "0x%8.8" PRIx64 ": DW_TAG_member '%s' refers to type 0x%8.8x"
+                " which was unable to be parsed",
+                die.GetID(), name, encoding_form.Reference().GetOffset());
+          else
+            module_sp->ReportError(
+                "0x%8.8" PRIx64 ": DW_TAG_member refers to type 0x%8.8x"
+                " which was unable to be parsed",
+                die.GetID(), encoding_form.Reference().GetOffset());
+        }
+      }
 
-            if (ivar_decl)
-              m_ast.SetMetadataAsUserID(ivar_decl, die.GetID());
-          }
+      if (prop_name != nullptr && member_type) {
+        clang::ObjCIvarDecl *ivar_decl = nullptr;
+
+        if (field_decl) {
+          ivar_decl = clang::dyn_cast<clang::ObjCIvarDecl>(field_decl);
+          assert(ivar_decl != nullptr);
         }
+
+        ClangASTMetadata metadata;
+        metadata.SetUserID(die.GetID());
+        delayed_properties.push_back(DelayedAddObjCClassProperty(
+            class_clang_type, prop_name, member_type->GetLayoutCompilerType(),
+            ivar_decl, prop_setter_name, prop_getter_name, prop_attributes,
+            &metadata));
+
+        if (ivar_decl)
+          m_ast.SetMetadataAsUserID(ivar_decl, die.GetID());
       }
-      ++member_idx;
-    } break;
+    }
+  }
+}
+
+bool DWARFASTParserClang::ParseChildMembers(
+    const DWARFDIE &parent_die, CompilerType &class_clang_type,
+    const LanguageType class_language,
+    std::vector<std::unique_ptr<clang::CXXBaseSpecifier>> &base_classes,
+    std::vector<int> &member_accessibilities,
+    std::vector<DWARFDIE> &member_function_dies,
+    DelayedPropertyList &delayed_properties, AccessType &default_accessibility,
+    bool &is_a_class, ClangASTImporter::LayoutInfo &layout_info) {
+  if (!parent_die)
+    return false;
+
+  BitfieldInfo last_field_info;
+
+  ModuleSP module_sp = parent_die.GetDWARF()->GetObjectFile()->GetModule();
+  ClangASTContext *ast =
+      llvm::dyn_cast_or_null<ClangASTContext>(class_clang_type.GetTypeSystem());
+  if (ast == nullptr)
+    return false;
+
+  for (DWARFDIE die = parent_die.GetFirstChild(); die.IsValid();
+       die = die.GetSibling()) {
+    dw_tag_t tag = die.Tag();
+
+    switch (tag) {
+    case DW_TAG_member:
+    case DW_TAG_APPLE_property:
+      ParseSingleMember(die, parent_die, class_clang_type, class_language,
+                        member_accessibilities, default_accessibility,
+                        delayed_properties, layout_info, last_field_info);
+      break;
 
     case DW_TAG_subprogram:
       // Let the type parsing code handle this one for us.
@@ -3552,18 +3522,20 @@ DWARFASTParserClang::ResolveNamespaceDIE(const DWARFDIE &die) {
         SymbolFileDWARF *dwarf = die.GetDWARF();
         if (namespace_name) {
           dwarf->GetObjectFile()->GetModule()->LogMessage(
-              log, "ASTContext => %p: 0x%8.8" PRIx64
-                   ": DW_TAG_namespace with DW_AT_name(\"%s\") => "
-                   "clang::NamespaceDecl *%p (original = %p)",
-              static_cast<void *>(m_ast.getASTContext()), die.GetID(),
+              log,
+              "ASTContext => %p: 0x%8.8" PRIx64
+              ": DW_TAG_namespace with DW_AT_name(\"%s\") => "
+              "clang::NamespaceDecl *%p (original = %p)",
+              static_cast<void *>(&m_ast.getASTContext()), die.GetID(),
               namespace_name, static_cast<void *>(namespace_decl),
               static_cast<void *>(namespace_decl->getOriginalNamespace()));
         } else {
           dwarf->GetObjectFile()->GetModule()->LogMessage(
-              log, "ASTContext => %p: 0x%8.8" PRIx64
-                   ": DW_TAG_namespace (anonymous) => clang::NamespaceDecl *%p "
-                   "(original = %p)",
-              static_cast<void *>(m_ast.getASTContext()), die.GetID(),
+              log,
+              "ASTContext => %p: 0x%8.8" PRIx64
+              ": DW_TAG_namespace (anonymous) => clang::NamespaceDecl *%p "
+              "(original = %p)",
+              static_cast<void *>(&m_ast.getASTContext()), die.GetID(),
               static_cast<void *>(namespace_decl),
               static_cast<void *>(namespace_decl->getOriginalNamespace()));
         }
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.h b/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.h
index 106f9254a449..4ad757247c3e 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.h
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.h
@@ -128,7 +128,8 @@ protected:
                                const DWARFDIE &parent_die);
 
   /// Parse a structure, class, or union type DIE.
-  lldb::TypeSP ParseStructureLikeDIE(const DWARFDIE &die,
+  lldb::TypeSP ParseStructureLikeDIE(const lldb_private::SymbolContext &sc,
+                                     const DWARFDIE &die,
                                      ParsedDWARFTypeAttributes &attrs);
 
   lldb_private::Type *GetTypeForDIE(const DWARFDIE &die);
@@ -159,11 +160,73 @@ protected:
   UpdateSymbolContextScopeForType(const lldb_private::SymbolContext &sc,
                                   const DWARFDIE &die, lldb::TypeSP type_sp);
 
-  lldb::TypeSP ParseTypeFromDWO(const DWARFDIE &die, lldb_private::Log *log);
+  /// Follow Clang Module Skeleton CU references to find a type definition.
+  lldb::TypeSP ParseTypeFromClangModule(const lldb_private::SymbolContext &sc,
+                                        const DWARFDIE &die,
+                                        lldb_private::Log *log);
 
   // Return true if this type is a declaration to a type in an external
   // module.
   lldb::ModuleSP GetModuleForType(const DWARFDIE &die);
+
+private:
+  struct BitfieldInfo {
+    uint64_t bit_size;
+    uint64_t bit_offset;
+
+    BitfieldInfo()
+        : bit_size(LLDB_INVALID_ADDRESS), bit_offset(LLDB_INVALID_ADDRESS) {}
+
+    void Clear() {
+      bit_size = LLDB_INVALID_ADDRESS;
+      bit_offset = LLDB_INVALID_ADDRESS;
+    }
+
+    bool IsValid() const {
+      return (bit_size != LLDB_INVALID_ADDRESS) &&
+             (bit_offset != LLDB_INVALID_ADDRESS);
+    }
+
+    bool NextBitfieldOffsetIsValid(const uint64_t next_bit_offset) const {
+      if (IsValid()) {
+        // This bitfield info is valid, so any subsequent bitfields must not
+        // overlap and must be at a higher bit offset than any previous bitfield
+        // + size.
+        return (bit_size + bit_offset) <= next_bit_offset;
+      } else {
+        // If the this BitfieldInfo is not valid, then any offset isOK
+        return true;
+      }
+    }
+  };
+
+  void
+  ParseSingleMember(const DWARFDIE &die, const DWARFDIE &parent_die,
+                    lldb_private::CompilerType &class_clang_type,
+                    const lldb::LanguageType class_language,
+                    std::vector<int> &member_accessibilities,
+                    lldb::AccessType &default_accessibility,
+                    DelayedPropertyList &delayed_properties,
+                    lldb_private::ClangASTImporter::LayoutInfo &layout_info,
+                    BitfieldInfo &last_field_info);
+
+  bool CompleteRecordType(const DWARFDIE &die, lldb_private::Type *type,
+                          lldb_private::CompilerType &clang_type);
+  bool CompleteEnumType(const DWARFDIE &die, lldb_private::Type *type,
+                        lldb_private::CompilerType &clang_type);
+
+  lldb::TypeSP ParseTypeModifier(const lldb_private::SymbolContext &sc,
+                                 const DWARFDIE &die,
+                                 ParsedDWARFTypeAttributes &attrs);
+  lldb::TypeSP ParseEnum(const lldb_private::SymbolContext &sc,
+                         const DWARFDIE &die, ParsedDWARFTypeAttributes &attrs);
+  lldb::TypeSP ParseSubroutine(const DWARFDIE &die,
+                               ParsedDWARFTypeAttributes &attrs);
+  // FIXME: attrs should be passed as a const reference.
+  lldb::TypeSP ParseArrayType(const DWARFDIE &die,
+                              ParsedDWARFTypeAttributes &attrs);
+  lldb::TypeSP ParsePointerToMemberType(const DWARFDIE &die,
+                                        const ParsedDWARFTypeAttributes &attrs);
 };
 
 /// Parsed form of all attributes that are relevant for type reconstruction.
@@ -181,6 +244,8 @@ struct ParsedDWARFTypeAttributes {
   bool is_scoped_enum = false;
   bool is_vector = false;
   bool is_virtual = false;
+  bool is_objc_direct_call = false;
+  bool exports_symbols = false;
   clang::StorageClass storage = clang::SC_None;
   const char *mangled_name = nullptr;
   lldb_private::ConstString name;
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFCompileUnit.h b/lldb/source/Plugins/SymbolFile/DWARF/DWARFCompileUnit.h
index 75647dbb082f..454637ef981c 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFCompileUnit.h
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFCompileUnit.h
@@ -24,8 +24,8 @@ private:
   DWARFCompileUnit(SymbolFileDWARF &dwarf, lldb::user_id_t uid,
                    const DWARFUnitHeader &header,
                    const DWARFAbbreviationDeclarationSet &abbrevs,
-                   DIERef::Section section)
-      : DWARFUnit(dwarf, uid, header, abbrevs, section) {}
+                   DIERef::Section section, bool is_dwo)
+      : DWARFUnit(dwarf, uid, header, abbrevs, section, is_dwo) {}
 
   DISALLOW_COPY_AND_ASSIGN(DWARFCompileUnit);
 
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFContext.cpp b/lldb/source/Plugins/SymbolFile/DWARF/DWARFContext.cpp
index eb307ce1cce1..5052b825fea6 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFContext.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFContext.cpp
@@ -70,6 +70,17 @@ const DWARFDataExtractor &DWARFContext::getOrLoadLineStrData() {
                           m_data_debug_line_str);
 }
 
+const DWARFDataExtractor &DWARFContext::getOrLoadLocData() {
+  return LoadOrGetSection(eSectionTypeDWARFDebugLoc,
+                          eSectionTypeDWARFDebugLocDwo, m_data_debug_loc);
+}
+
+const DWARFDataExtractor &DWARFContext::getOrLoadLocListsData() {
+  return LoadOrGetSection(eSectionTypeDWARFDebugLocLists,
+                          eSectionTypeDWARFDebugLocListsDwo,
+                          m_data_debug_loclists);
+}
+
 const DWARFDataExtractor &DWARFContext::getOrLoadMacroData() {
   return LoadOrGetSection(eSectionTypeDWARFDebugMacro, llvm::None,
                           m_data_debug_macro);
@@ -81,7 +92,8 @@ const DWARFDataExtractor &DWARFContext::getOrLoadRangesData() {
 }
 
 const DWARFDataExtractor &DWARFContext::getOrLoadRngListsData() {
-  return LoadOrGetSection(eSectionTypeDWARFDebugRngLists, llvm::None,
+  return LoadOrGetSection(eSectionTypeDWARFDebugRngLists,
+                          eSectionTypeDWARFDebugRngListsDwo,
                           m_data_debug_rnglists);
 }
 
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFContext.h b/lldb/source/Plugins/SymbolFile/DWARF/DWARFContext.h
index add042384039..8691001b1b76 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFContext.h
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFContext.h
@@ -34,6 +34,8 @@ private:
   SectionData m_data_debug_info;
   SectionData m_data_debug_line;
   SectionData m_data_debug_line_str;
+  SectionData m_data_debug_loc;
+  SectionData m_data_debug_loclists;
   SectionData m_data_debug_macro;
   SectionData m_data_debug_ranges;
   SectionData m_data_debug_rnglists;
@@ -41,8 +43,6 @@ private:
   SectionData m_data_debug_str_offsets;
   SectionData m_data_debug_types;
 
-  bool isDwo() { return m_dwo_section_list != nullptr; }
-
   const DWARFDataExtractor &
   LoadOrGetSection(lldb::SectionType main_section_type,
                    llvm::Optional<lldb::SectionType> dwo_section_type,
@@ -60,6 +60,8 @@ public:
   const DWARFDataExtractor &getOrLoadDebugInfoData();
   const DWARFDataExtractor &getOrLoadLineData();
   const DWARFDataExtractor &getOrLoadLineStrData();
+  const DWARFDataExtractor &getOrLoadLocData();
+  const DWARFDataExtractor &getOrLoadLocListsData();
   const DWARFDataExtractor &getOrLoadMacroData();
   const DWARFDataExtractor &getOrLoadRangesData();
   const DWARFDataExtractor &getOrLoadRngListsData();
@@ -67,6 +69,8 @@ public:
   const DWARFDataExtractor &getOrLoadStrOffsetsData();
   const DWARFDataExtractor &getOrLoadDebugTypesData();
 
+  bool isDwo() { return m_dwo_section_list != nullptr; }
+
   llvm::DWARFContext &GetAsLLVM();
 };
 } // namespace lldb_private
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFDIE.cpp b/lldb/source/Plugins/SymbolFile/DWARF/DWARFDIE.cpp
index 5ee0687995a1..c5411a17f274 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFDIE.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFDIE.cpp
@@ -406,39 +406,6 @@ bool DWARFDIE::IsMethod() const {
   return false;
 }
 
-DWARFDIE
-DWARFDIE::GetContainingDWOModuleDIE() const {
-  if (IsValid()) {
-    DWARFDIE top_module_die;
-    // Now make sure this DIE is scoped in a DW_TAG_module tag and return true
-    // if so
-    for (DWARFDIE parent = GetParent(); parent.IsValid();
-         parent = parent.GetParent()) {
-      const dw_tag_t tag = parent.Tag();
-      if (tag == DW_TAG_module)
-        top_module_die = parent;
-      else if (tag == DW_TAG_compile_unit || tag == DW_TAG_partial_unit)
-        break;
-    }
-
-    return top_module_die;
-  }
-  return DWARFDIE();
-}
-
-lldb::ModuleSP DWARFDIE::GetContainingDWOModule() const {
-  if (IsValid()) {
-    DWARFDIE dwo_module_die = GetContainingDWOModuleDIE();
-
-    if (dwo_module_die) {
-      const char *module_name = dwo_module_die.GetName();
-      if (module_name)
-        return GetDWARF()->GetDWOModule(lldb_private::ConstString(module_name));
-    }
-  }
-  return lldb::ModuleSP();
-}
-
 bool DWARFDIE::GetDIENamesAndRanges(
     const char *&name, const char *&mangled, DWARFRangeList &ranges,
     int &decl_file, int &decl_line, int &decl_column, int &call_file,
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFDIE.h b/lldb/source/Plugins/SymbolFile/DWARF/DWARFDIE.h
index a779c589611a..87d52eee9dd9 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFDIE.h
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFDIE.h
@@ -22,10 +22,6 @@ public:
   bool IsMethod() const;
 
   // Accessors
-  lldb::ModuleSP GetContainingDWOModule() const;
-
-  DWARFDIE
-  GetContainingDWOModuleDIE() const;
 
   // Accessing information about a DIE
   const char *GetMangledName() const;
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugInfo.h b/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugInfo.h
index d1b066ffe80c..056cf33a202f 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugInfo.h
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugInfo.h
@@ -16,7 +16,6 @@
 #include "DWARFTypeUnit.h"
 #include "DWARFUnit.h"
 #include "SymbolFileDWARF.h"
-#include "lldb/Core/STLUtils.h"
 #include "lldb/lldb-private.h"
 #include "llvm/Support/Error.h"
 
@@ -24,11 +23,6 @@ namespace lldb_private {
 class DWARFContext;
 }
 
-typedef std::multimap<const char *, dw_offset_t, CStringCompareFunctionObject>
-    CStringToDIEMap;
-typedef CStringToDIEMap::iterator CStringToDIEMapIter;
-typedef CStringToDIEMap::const_iterator CStringToDIEMapConstIter;
-
 class DWARFDebugInfo {
 public:
   typedef dw_offset_t (*Callback)(SymbolFileDWARF *dwarf2Data,
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugInfoEntry.cpp b/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugInfoEntry.cpp
index 8c0fbeb4b717..320500fe608d 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugInfoEntry.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugInfoEntry.cpp
@@ -156,6 +156,7 @@ bool DWARFDebugInfoEntry::Extract(const DWARFDataExtractor &data,
 
           // signed or unsigned LEB 128 values
           case DW_FORM_addrx:
+          case DW_FORM_loclistx:
           case DW_FORM_rnglistx:
           case DW_FORM_sdata:
           case DW_FORM_udata:
@@ -200,7 +201,7 @@ bool DWARFDebugInfoEntry::Extract(const DWARFDataExtractor &data,
   return false;
 }
 
-static DWARFRangeList GetRangesOrReportError(const DWARFUnit &unit,
+static DWARFRangeList GetRangesOrReportError(DWARFUnit &unit,
                                              const DWARFDebugInfoEntry &die,
                                              const DWARFFormValue &value) {
   llvm::Expected<DWARFRangeList> expected_ranges =
@@ -223,7 +224,7 @@ static DWARFRangeList GetRangesOrReportError(const DWARFUnit &unit,
 // Gets the valid address ranges for a given DIE by looking for a
 // DW_AT_low_pc/DW_AT_high_pc pair, DW_AT_entry_pc, or DW_AT_ranges attributes.
 bool DWARFDebugInfoEntry::GetDIENamesAndRanges(
-    const DWARFUnit *cu, const char *&name, const char *&mangled,
+    DWARFUnit *cu, const char *&name, const char *&mangled,
     DWARFRangeList &ranges, int &decl_file, int &decl_line, int &decl_column,
     int &call_file, int &call_line, int &call_column,
     DWARFExpression *frame_base) const {
@@ -343,15 +344,15 @@ bool DWARFDebugInfoEntry::GetDIENamesAndRanges(
               *frame_base = DWARFExpression(
                   module, DataExtractor(data, block_offset, block_length), cu);
             } else {
-              DataExtractor data = dwarf.DebugLocData();
+              DataExtractor data = cu->GetLocationData();
               const dw_offset_t offset = form_value.Unsigned();
               if (data.ValidOffset(offset)) {
                 data = DataExtractor(data, offset, data.GetByteSize() - offset);
                 *frame_base = DWARFExpression(module, data, cu);
                 if (lo_pc != LLDB_INVALID_ADDRESS) {
                   assert(lo_pc >= cu->GetBaseAddress());
-                  frame_base->SetLocationListSlide(lo_pc -
-                                                   cu->GetBaseAddress());
+                  frame_base->SetLocationListAddresses(cu->GetBaseAddress(),
+                                                       lo_pc);
                 } else {
                   set_frame_base_loclist_addr = true;
                 }
@@ -379,7 +380,7 @@ bool DWARFDebugInfoEntry::GetDIENamesAndRanges(
   if (set_frame_base_loclist_addr) {
     dw_addr_t lowest_range_pc = ranges.GetMinRangeBase(0);
     assert(lowest_range_pc >= cu->GetBaseAddress());
-    frame_base->SetLocationListSlide(lowest_range_pc - cu->GetBaseAddress());
+    frame_base->SetLocationListAddresses(cu->GetBaseAddress(), lowest_range_pc);
   }
 
   if (ranges.IsEmpty() || name == nullptr || mangled == nullptr) {
@@ -477,8 +478,6 @@ void DWARFDebugInfoEntry::DumpAttribute(
 
   s.PutCString("( ");
 
-  SymbolFileDWARF &dwarf = cu->GetSymbolFileDWARF();
-
   // Check to see if we have any special attribute formatters
   switch (attr) {
   case DW_AT_stmt_list:
@@ -508,7 +507,7 @@ void DWARFDebugInfoEntry::DumpAttribute(
       // We have a location list offset as the value that is the offset into
       // the .debug_loc section that describes the value over it's lifetime
       uint64_t debug_loc_offset = form_value.Unsigned();
-      DWARFExpression::PrintDWARFLocationList(s, cu, dwarf.DebugLocData(),
+      DWARFExpression::PrintDWARFLocationList(s, cu, cu->GetLocationData(),
                                               debug_loc_offset);
     }
   } break;
@@ -646,25 +645,7 @@ dw_offset_t DWARFDebugInfoEntry::GetAttributeValue(
       }
     }
   }
-
-  // If we're a unit DIE, also check the attributes of the dwo unit (if any).
-  if (GetParent())
-    return 0;
-  SymbolFileDWARFDwo *dwo_symbol_file = cu->GetDwoSymbolFile();
-  if (!dwo_symbol_file)
-    return 0;
-
-  DWARFCompileUnit *dwo_cu = dwo_symbol_file->GetCompileUnit();
-  if (!dwo_cu)
-    return 0;
-
-  DWARFBaseDIE dwo_cu_die = dwo_cu->GetUnitDIEOnly();
-  if (!dwo_cu_die.IsValid())
-    return 0;
-
-  return dwo_cu_die.GetDIE()->GetAttributeValue(
-      dwo_cu, attr, form_value, end_attr_offset_ptr,
-      check_specification_or_abstract_origin);
+  return 0;
 }
 
 // GetAttributeValueAsString
@@ -766,7 +747,7 @@ bool DWARFDebugInfoEntry::GetAttributeAddressRange(
 }
 
 size_t DWARFDebugInfoEntry::GetAttributeAddressRanges(
-    const DWARFUnit *cu, DWARFRangeList &ranges, bool check_hi_lo_pc,
+    DWARFUnit *cu, DWARFRangeList &ranges, bool check_hi_lo_pc,
     bool check_specification_or_abstract_origin) const {
   ranges.Clear();
 
@@ -1012,8 +993,7 @@ DWARFDebugInfoEntry::GetQualifiedName(DWARFUnit *cu,
   return storage.c_str();
 }
 
-bool DWARFDebugInfoEntry::LookupAddress(const dw_addr_t address,
-                                        const DWARFUnit *cu,
+bool DWARFDebugInfoEntry::LookupAddress(const dw_addr_t address, DWARFUnit *cu,
                                         DWARFDebugInfoEntry **function_die,
                                         DWARFDebugInfoEntry **block_die) {
   bool found_address = false;
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugInfoEntry.h b/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugInfoEntry.h
index 25c885608d85..f35af6e7d498 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugInfoEntry.h
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugInfoEntry.h
@@ -23,6 +23,10 @@ class DWARFDeclContext;
 
 #define DIE_SIBLING_IDX_BITSIZE 31
 
+/// DWARFDebugInfoEntry objects assume that they are living in one big
+/// vector and do pointer arithmetic on their this pointers. Don't
+/// pass them by value. Due to the way they are constructed in a
+/// std::vector, we cannot delete the copy constructor.
 class DWARFDebugInfoEntry {
 public:
   typedef std::vector<DWARFDebugInfoEntry> collection;
@@ -46,7 +50,7 @@ public:
   bool Extract(const lldb_private::DWARFDataExtractor &data,
                const DWARFUnit *cu, lldb::offset_t *offset_ptr);
 
-  bool LookupAddress(const dw_addr_t address, const DWARFUnit *cu,
+  bool LookupAddress(const dw_addr_t address, DWARFUnit *cu,
                      DWARFDebugInfoEntry **function_die,
                      DWARFDebugInfoEntry **block_die);
 
@@ -87,7 +91,7 @@ public:
       bool check_specification_or_abstract_origin = false) const;
 
   size_t GetAttributeAddressRanges(
-      const DWARFUnit *cu, DWARFRangeList &ranges, bool check_hi_lo_pc,
+      DWARFUnit *cu, DWARFRangeList &ranges, bool check_hi_lo_pc,
       bool check_specification_or_abstract_origin = false) const;
 
   const char *GetName(const DWARFUnit *cu) const;
@@ -112,7 +116,7 @@ public:
                 dw_attr_t attr, DWARFFormValue &form_value);
 
   bool GetDIENamesAndRanges(
-      const DWARFUnit *cu, const char *&name, const char *&mangled,
+      DWARFUnit *cu, const char *&name, const char *&mangled,
       DWARFRangeList &rangeList, int &decl_file, int &decl_line,
       int &decl_column, int &call_file, int &call_line, int &call_column,
       lldb_private::DWARFExpression *frame_base = nullptr) const;
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugRanges.cpp b/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugRanges.cpp
index 0b08fa09f906..6c074002cb20 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugRanges.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugRanges.cpp
@@ -95,13 +95,15 @@ void DWARFDebugRanges::Dump(Stream &s,
     } else if (begin == LLDB_INVALID_ADDRESS) {
       // A base address selection entry
       base_addr = end;
-      s.Address(base_addr, sizeof(dw_addr_t), " Base address = ");
+      DumpAddress(s.AsRawOstream(), base_addr, sizeof(dw_addr_t),
+                  " Base address = ");
     } else {
       // Convert from offset to an address
       dw_addr_t begin_addr = begin + base_addr;
       dw_addr_t end_addr = end + base_addr;
 
-      s.AddressRange(begin_addr, end_addr, sizeof(dw_addr_t), nullptr);
+      DumpAddressRange(s.AsRawOstream(), begin_addr, end_addr,
+                       sizeof(dw_addr_t), nullptr);
     }
   }
 }
@@ -122,164 +124,3 @@ bool DWARFDebugRanges::FindRanges(const DWARFUnit *cu,
   }
   return false;
 }
-
-bool DWARFDebugRngLists::ExtractRangeList(
-    const DWARFDataExtractor &data, uint8_t addrSize,
-    lldb::offset_t *offset_ptr, std::vector<RngListEntry> &rangeList) {
-  rangeList.clear();
-
-  bool error = false;
-  while (!error) {
-    switch (data.GetU8(offset_ptr)) {
-    case DW_RLE_end_of_list:
-      return true;
-
-    case DW_RLE_start_length: {
-      dw_addr_t begin = data.GetMaxU64(offset_ptr, addrSize);
-      dw_addr_t len = data.GetULEB128(offset_ptr);
-      rangeList.push_back({DW_RLE_start_length, begin, len});
-      break;
-    }
-
-    case DW_RLE_start_end: {
-      dw_addr_t begin = data.GetMaxU64(offset_ptr, addrSize);
-      dw_addr_t end = data.GetMaxU64(offset_ptr, addrSize);
-      rangeList.push_back({DW_RLE_start_end, begin, end});
-      break;
-    }
-
-    case DW_RLE_base_address: {
-      dw_addr_t base = data.GetMaxU64(offset_ptr, addrSize);
-      rangeList.push_back({DW_RLE_base_address, base, 0});
-      break;
-    }
-
-    case DW_RLE_offset_pair: {
-      dw_addr_t begin = data.GetULEB128(offset_ptr);
-      dw_addr_t end = data.GetULEB128(offset_ptr);
-      rangeList.push_back({DW_RLE_offset_pair, begin, end});
-      break;
-    }
-
-    case DW_RLE_base_addressx: {
-      dw_addr_t base = data.GetULEB128(offset_ptr);
-      rangeList.push_back({DW_RLE_base_addressx, base, 0});
-      break;
-    }
-
-    case DW_RLE_startx_endx: {
-      dw_addr_t start = data.GetULEB128(offset_ptr);
-      dw_addr_t end = data.GetULEB128(offset_ptr);
-      rangeList.push_back({DW_RLE_startx_endx, start, end});
-      break;
-    }
-
-    case DW_RLE_startx_length: {
-      dw_addr_t start = data.GetULEB128(offset_ptr);
-      dw_addr_t length = data.GetULEB128(offset_ptr);
-      rangeList.push_back({DW_RLE_startx_length, start, length});
-      break;
-    }
-
-    default:
-      lldbassert(0 && "unknown range list entry encoding");
-      error = true;
-    }
-  }
-
-  return false;
-}
-
-static uint64_t ReadAddressFromDebugAddrSection(const DWARFUnit *cu,
-                                                uint32_t index) {
-  uint32_t index_size = cu->GetAddressByteSize();
-  dw_offset_t addr_base = cu->GetAddrBase();
-  lldb::offset_t offset = addr_base + index * index_size;
-  return cu->GetSymbolFileDWARF()
-      .GetDWARFContext()
-      .getOrLoadAddrData()
-      .GetMaxU64(&offset, index_size);
-}
-
-bool DWARFDebugRngLists::FindRanges(const DWARFUnit *cu,
-                                    dw_offset_t debug_ranges_offset,
-                                    DWARFRangeList &range_list) const {
-  range_list.Clear();
-  dw_addr_t debug_ranges_address = cu->GetRangesBase() + debug_ranges_offset;
-  auto pos = m_range_map.find(debug_ranges_address);
-  if (pos != m_range_map.end()) {
-    dw_addr_t BaseAddr = cu->GetBaseAddress();
-    for (const RngListEntry &E : pos->second) {
-      switch (E.encoding) {
-      case DW_RLE_start_length:
-        range_list.Append(DWARFRangeList::Entry(E.value0, E.value1));
-        break;
-      case DW_RLE_base_address:
-        BaseAddr = E.value0;
-        break;
-      case DW_RLE_start_end:
-        range_list.Append(DWARFRangeList::Entry(E.value0, E.value1 - E.value0));
-        break;
-      case DW_RLE_offset_pair:
-        range_list.Append(
-            DWARFRangeList::Entry(BaseAddr + E.value0, E.value1 - E.value0));
-        break;
-      case DW_RLE_base_addressx: {
-        BaseAddr = ReadAddressFromDebugAddrSection(cu, E.value0);
-        break;
-      }
-      case DW_RLE_startx_endx: {
-        dw_addr_t start = ReadAddressFromDebugAddrSection(cu, E.value0);
-        dw_addr_t end = ReadAddressFromDebugAddrSection(cu, E.value1);
-        range_list.Append(DWARFRangeList::Entry(start, end - start));
-        break;
-      }
-      case DW_RLE_startx_length: {
-        dw_addr_t start = ReadAddressFromDebugAddrSection(cu, E.value0);
-        range_list.Append(DWARFRangeList::Entry(start, E.value1));
-        break;
-      }
-      default:
-        llvm_unreachable("unexpected encoding");
-      }
-    }
-    return true;
-  }
-  return false;
-}
-
-void DWARFDebugRngLists::Extract(DWARFContext &context) {
-  const DWARFDataExtractor &data = context.getOrLoadRngListsData();
-  lldb::offset_t offset = 0;
-
-  uint64_t length = data.GetU32(&offset);
-  // FIXME: Handle DWARF64.
-  lldb::offset_t end = offset + length;
-
-  // Check version.
-  if (data.GetU16(&offset) < 5)
-    return;
-
-  uint8_t addrSize = data.GetU8(&offset);
-
-  // We do not support non-zero segment selector size.
-  if (data.GetU8(&offset) != 0) {
-    lldbassert(0 && "not implemented");
-    return;
-  }
-
-  uint32_t offsetsAmount = data.GetU32(&offset);
-  for (uint32_t i = 0; i < offsetsAmount; ++i)
-    Offsets.push_back(data.GetMaxU64(&offset, 4));
-
-  lldb::offset_t listOffset = offset;
-  std::vector<RngListEntry> rangeList;
-  while (offset < end && ExtractRangeList(data, addrSize, &offset, rangeList)) {
-    m_range_map[listOffset] = rangeList;
-    listOffset = offset;
-  }
-}
-
-uint64_t DWARFDebugRngLists::GetOffset(size_t Index) const {
-  return Offsets[Index];
-}
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugRanges.h b/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugRanges.h
index c398259056b3..1888a7760f27 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugRanges.h
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugRanges.h
@@ -17,22 +17,13 @@ namespace lldb_private {
 class DWARFContext;
 }
 
-class DWARFDebugRangesBase {
-public:
-  virtual ~DWARFDebugRangesBase(){};
-
-  virtual void Extract(lldb_private::DWARFContext &context) = 0;
-  virtual bool FindRanges(const DWARFUnit *cu, dw_offset_t debug_ranges_offset,
-                          DWARFRangeList &range_list) const = 0;
-};
-
-class DWARFDebugRanges final : public DWARFDebugRangesBase {
+class DWARFDebugRanges {
 public:
   DWARFDebugRanges();
 
-  void Extract(lldb_private::DWARFContext &context) override;
+  void Extract(lldb_private::DWARFContext &context);
   bool FindRanges(const DWARFUnit *cu, dw_offset_t debug_ranges_offset,
-                  DWARFRangeList &range_list) const override;
+                  DWARFRangeList &range_list) const;
 
   static void Dump(lldb_private::Stream &s,
                    const lldb_private::DWARFDataExtractor &debug_ranges_data,
@@ -48,27 +39,4 @@ protected:
   range_map m_range_map;
 };
 
-// DWARF v5 .debug_rnglists section.
-class DWARFDebugRngLists final : public DWARFDebugRangesBase {
-  struct RngListEntry {
-    uint8_t encoding;
-    uint64_t value0;
-    uint64_t value1;
-  };
-
-public:
-  void Extract(lldb_private::DWARFContext &context) override;
-  bool FindRanges(const DWARFUnit *cu, dw_offset_t debug_ranges_offset,
-                  DWARFRangeList &range_list) const override;
-  uint64_t GetOffset(size_t Index) const;
-
-protected:
-  bool ExtractRangeList(const lldb_private::DWARFDataExtractor &data,
-                        uint8_t addrSize, lldb::offset_t *offset_ptr,
-                        std::vector<RngListEntry> &list);
-
-  std::vector<uint64_t> Offsets;
-  std::map<dw_offset_t, std::vector<RngListEntry>> m_range_map;
-};
-
 #endif // SymbolFileDWARF_DWARFDebugRanges_h_
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFDeclContext.h b/lldb/source/Plugins/SymbolFile/DWARF/DWARFDeclContext.h
index 6501ac27f27d..348b33464a54 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFDeclContext.h
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFDeclContext.h
@@ -63,7 +63,7 @@ public:
 
   const char *GetQualifiedName() const;
 
-  // Same as GetQaulifiedName, but the life time of the returned string will
+  // Same as GetQualifiedName, but the life time of the returned string will
   // be that of the LLDB session.
   lldb_private::ConstString GetQualifiedNameAsConstString() const {
     return lldb_private::ConstString(GetQualifiedName());
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFFormValue.cpp b/lldb/source/Plugins/SymbolFile/DWARF/DWARFFormValue.cpp
index 046ae67446af..f660cc32b3f8 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFFormValue.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFFormValue.cpp
@@ -107,6 +107,7 @@ bool DWARFFormValue::ExtractValue(const DWARFDataExtractor &data,
       m_value.value.uval = data.GetU64(offset_ptr);
       break;
     case DW_FORM_addrx:
+    case DW_FORM_loclistx:
     case DW_FORM_rnglistx:
     case DW_FORM_strx:
     case DW_FORM_udata:
@@ -305,6 +306,7 @@ bool DWARFFormValue::SkipValue(dw_form_t form,
 
     // signed or unsigned LEB 128 values
     case DW_FORM_addrx:
+    case DW_FORM_loclistx:
     case DW_FORM_rnglistx:
     case DW_FORM_sdata:
     case DW_FORM_udata:
@@ -333,7 +335,7 @@ void DWARFFormValue::Dump(Stream &s) const {
 
   switch (m_form) {
   case DW_FORM_addr:
-    s.Address(uvalue, sizeof(uint64_t));
+    DumpAddress(s.AsRawOstream(), uvalue, sizeof(uint64_t));
     break;
   case DW_FORM_flag:
   case DW_FORM_data1:
@@ -409,10 +411,11 @@ void DWARFFormValue::Dump(Stream &s) const {
     assert(m_unit); // Unit must be valid for DW_FORM_ref_addr objects or we
                     // will get this wrong
     if (m_unit->GetVersion() <= 2)
-      s.Address(uvalue, sizeof(uint64_t) * 2);
+      DumpAddress(s.AsRawOstream(), uvalue, sizeof(uint64_t) * 2);
     else
-      s.Address(uvalue, 4 * 2); // 4 for DWARF32, 8 for DWARF64, but we don't
-                                // support DWARF64 yet
+      DumpAddress(s.AsRawOstream(), uvalue,
+                  4 * 2); // 4 for DWARF32, 8 for DWARF64, but we don't
+                          // support DWARF64 yet
     break;
   }
   case DW_FORM_ref1:
@@ -599,105 +602,11 @@ bool DWARFFormValue::IsDataForm(const dw_form_t form) {
   return false;
 }
 
-int DWARFFormValue::Compare(const DWARFFormValue &a_value,
-                            const DWARFFormValue &b_value) {
-  dw_form_t a_form = a_value.Form();
-  dw_form_t b_form = b_value.Form();
-  if (a_form < b_form)
-    return -1;
-  if (a_form > b_form)
-    return 1;
-  switch (a_form) {
-  case DW_FORM_addr:
-  case DW_FORM_addrx:
-  case DW_FORM_flag:
-  case DW_FORM_data1:
-  case DW_FORM_data2:
-  case DW_FORM_data4:
-  case DW_FORM_data8:
-  case DW_FORM_udata:
-  case DW_FORM_ref_addr:
-  case DW_FORM_sec_offset:
-  case DW_FORM_flag_present:
-  case DW_FORM_ref_sig8:
-  case DW_FORM_GNU_addr_index: {
-    uint64_t a = a_value.Unsigned();
-    uint64_t b = b_value.Unsigned();
-    if (a < b)
-      return -1;
-    if (a > b)
-      return 1;
-    return 0;
-  }
-
-  case DW_FORM_sdata: {
-    int64_t a = a_value.Signed();
-    int64_t b = b_value.Signed();
-    if (a < b)
-      return -1;
-    if (a > b)
-      return 1;
-    return 0;
-  }
-
-  case DW_FORM_string:
-  case DW_FORM_strp:
-  case DW_FORM_GNU_str_index: {
-    const char *a_string = a_value.AsCString();
-    const char *b_string = b_value.AsCString();
-    if (a_string == b_string)
-      return 0;
-    else if (a_string && b_string)
-      return strcmp(a_string, b_string);
-    else if (a_string == nullptr)
-      return -1; // A string is NULL, and B is valid
-    else
-      return 1; // A string valid, and B is NULL
-  }
-
-  case DW_FORM_block:
-  case DW_FORM_block1:
-  case DW_FORM_block2:
-  case DW_FORM_block4:
-  case DW_FORM_exprloc: {
-    uint64_t a_len = a_value.Unsigned();
-    uint64_t b_len = b_value.Unsigned();
-    if (a_len < b_len)
-      return -1;
-    if (a_len > b_len)
-      return 1;
-    // The block lengths are the same
-    return memcmp(a_value.BlockData(), b_value.BlockData(), a_value.Unsigned());
-  } break;
-
-  case DW_FORM_ref1:
-  case DW_FORM_ref2:
-  case DW_FORM_ref4:
-  case DW_FORM_ref8:
-  case DW_FORM_ref_udata: {
-    uint64_t a = a_value.m_value.value.uval;
-    uint64_t b = b_value.m_value.value.uval;
-    if (a < b)
-      return -1;
-    if (a > b)
-      return 1;
-    return 0;
-  }
-
-  case DW_FORM_indirect:
-    llvm_unreachable(
-        "This shouldn't happen after the form has been extracted...");
-
-  default:
-    llvm_unreachable("Unhandled DW_FORM");
-  }
-  return -1;
-}
-
 bool DWARFFormValue::FormIsSupported(dw_form_t form) {
   switch (form) {
     case DW_FORM_addr:
     case DW_FORM_addrx:
+    case DW_FORM_loclistx:
     case DW_FORM_rnglistx:
     case DW_FORM_block2:
     case DW_FORM_block4:
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFTypeUnit.h b/lldb/source/Plugins/SymbolFile/DWARF/DWARFTypeUnit.h
index 6ff73ecd8efa..8967509c081a 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFTypeUnit.h
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFTypeUnit.h
@@ -28,8 +28,8 @@ private:
   DWARFTypeUnit(SymbolFileDWARF &dwarf, lldb::user_id_t uid,
                 const DWARFUnitHeader &header,
                 const DWARFAbbreviationDeclarationSet &abbrevs,
-                DIERef::Section section)
-      : DWARFUnit(dwarf, uid, header, abbrevs, section) {}
+                DIERef::Section section, bool is_dwo)
+      : DWARFUnit(dwarf, uid, header, abbrevs, section, is_dwo) {}
 
   friend class DWARFUnit;
 };
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.cpp b/lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.cpp
index 9964cf4b893c..22e3e40dac93 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.cpp
@@ -32,9 +32,9 @@ extern int g_verbose;
 DWARFUnit::DWARFUnit(SymbolFileDWARF &dwarf, lldb::user_id_t uid,
                      const DWARFUnitHeader &header,
                      const DWARFAbbreviationDeclarationSet &abbrevs,
-                     DIERef::Section section)
+                     DIERef::Section section, bool is_dwo)
     : UserID(uid), m_dwarf(dwarf), m_header(header), m_abbrevs(&abbrevs),
-      m_cancel_scopes(false), m_section(section) {}
+      m_cancel_scopes(false), m_section(section), m_is_dwo(is_dwo) {}
 
 DWARFUnit::~DWARFUnit() = default;
 
@@ -287,15 +287,27 @@ void DWARFUnit::AddUnitDIE(const DWARFDebugInfoEntry &cu_die) {
 
   DWARFAttributes attributes;
   size_t num_attributes = cu_die.GetAttributes(this, attributes);
+
+  // Extract DW_AT_addr_base first, as other attributes may need it.
+  for (size_t i = 0; i < num_attributes; ++i) {
+    if (attributes.AttributeAtIndex(i) != DW_AT_addr_base)
+      continue;
+    DWARFFormValue form_value;
+    if (attributes.ExtractFormValueAtIndex(i, form_value)) {
+      addr_base = form_value.Unsigned();
+      SetAddrBase(*addr_base);
+      break;
+    }
+  }
+
   for (size_t i = 0; i < num_attributes; ++i) {
     dw_attr_t attr = attributes.AttributeAtIndex(i);
     DWARFFormValue form_value;
     if (!attributes.ExtractFormValueAtIndex(i, form_value))
       continue;
     switch (attr) {
-    case DW_AT_addr_base:
-      addr_base = form_value.Unsigned();
-      SetAddrBase(*addr_base);
+    case DW_AT_loclists_base:
+      SetLoclistsBase(form_value.Unsigned());
       break;
     case DW_AT_rnglists_base:
       ranges_base = form_value.Unsigned();
@@ -324,6 +336,9 @@ void DWARFUnit::AddUnitDIE(const DWARFDebugInfoEntry &cu_die) {
     }
   }
 
+  if (m_is_dwo)
+    return;
+
   std::unique_ptr<SymbolFileDWARFDwo> dwo_symbol_file =
       m_dwarf.GetDwoSymbolFileForCompileUnit(*this, cu_die);
   if (!dwo_symbol_file)
@@ -358,10 +373,18 @@ void DWARFUnit::AddUnitDIE(const DWARFDebugInfoEntry &cu_die) {
   else if (gnu_addr_base)
     dwo_cu->SetAddrBase(*gnu_addr_base);
 
-  if (ranges_base)
-    dwo_cu->SetRangesBase(*ranges_base);
-  else if (gnu_ranges_base)
+  if (GetVersion() <= 4 && gnu_ranges_base)
     dwo_cu->SetRangesBase(*gnu_ranges_base);
+  else if (m_dwo_symbol_file->GetDWARFContext()
+               .getOrLoadRngListsData()
+               .GetByteSize() > 0)
+    dwo_cu->SetRangesBase(llvm::DWARFListTableHeader::getHeaderSize(DWARF32));
+
+  if (GetVersion() >= 5 && m_dwo_symbol_file->GetDWARFContext()
+                                   .getOrLoadLocListsData()
+                                   .GetByteSize() > 0)
+    dwo_cu->SetLoclistsBase(llvm::DWARFListTableHeader::getHeaderSize(DWARF32));
+  dwo_cu->SetBaseAddress(GetBaseAddress());
 
   for (size_t i = 0; i < m_dwo_symbol_file->DebugInfo()->GetNumUnits(); ++i) {
     DWARFUnit *unit = m_dwo_symbol_file->DebugInfo()->GetUnitAtIndex(i);
@@ -380,24 +403,6 @@ DWARFDIE DWARFUnit::LookupAddress(const dw_addr_t address) {
   return DWARFDIE();
 }
 
-size_t DWARFUnit::AppendDIEsWithTag(const dw_tag_t tag,
-                                    std::vector<DWARFDIE> &dies,
-                                    uint32_t depth) const {
-  size_t old_size = dies.size();
-  {
-    llvm::sys::ScopedReader lock(m_die_array_mutex);
-    DWARFDebugInfoEntry::const_iterator pos;
-    DWARFDebugInfoEntry::const_iterator end = m_die_array.end();
-    for (pos = m_die_array.begin(); pos != end; ++pos) {
-      if (pos->Tag() == tag)
-        dies.emplace_back(this, &(*pos));
-    }
-  }
-
-  // Return the number of DIEs added to the collection
-  return dies.size() - old_size;
-}
-
 size_t DWARFUnit::GetDebugInfoSize() const {
   return GetLengthByteSize() + GetLength() - GetHeaderByteSize();
 }
@@ -417,8 +422,79 @@ dw_offset_t DWARFUnit::GetLineTableOffset() {
 
 void DWARFUnit::SetAddrBase(dw_addr_t addr_base) { m_addr_base = addr_base; }
 
+// Parse the rangelist table header, including the optional array of offsets
+// following it (DWARF v5 and later).
+template <typename ListTableType>
+static llvm::Expected<ListTableType>
+ParseListTableHeader(const llvm::DWARFDataExtractor &data, uint64_t offset,
+                     DwarfFormat format) {
+  // We are expected to be called with Offset 0 or pointing just past the table
+  // header. Correct Offset in the latter case so that it points to the start
+  // of the header.
+  if (offset > 0) {
+    uint64_t HeaderSize = llvm::DWARFListTableHeader::getHeaderSize(format);
+    if (offset < HeaderSize)
+      return llvm::createStringError(errc::invalid_argument,
+                                     "did not detect a valid"
+                                     " list table with base = 0x%" PRIx64 "\n",
+                                     offset);
+    offset -= HeaderSize;
+  }
+  ListTableType Table;
+  if (llvm::Error E = Table.extractHeaderAndOffsets(data, &offset))
+    return std::move(E);
+  return Table;
+}
+
+void DWARFUnit::SetLoclistsBase(dw_addr_t loclists_base) {
+  m_loclists_base = loclists_base;
+
+  uint64_t header_size = llvm::DWARFListTableHeader::getHeaderSize(DWARF32);
+  if (loclists_base < header_size)
+    return;
+
+  m_loclist_table_header.emplace(".debug_loclists", "locations");
+  uint64_t offset = loclists_base - header_size;
+  if (llvm::Error E = m_loclist_table_header->extract(
+          m_dwarf.GetDWARFContext().getOrLoadLocListsData().GetAsLLVM(),
+          &offset)) {
+    GetSymbolFileDWARF().GetObjectFile()->GetModule()->ReportError(
+        "Failed to extract location list table at offset 0x%" PRIx64 ": %s",
+        loclists_base, toString(std::move(E)).c_str());
+  }
+}
+
+std::unique_ptr<llvm::DWARFLocationTable>
+DWARFUnit::GetLocationTable(const DataExtractor &data) const {
+  llvm::DWARFDataExtractor llvm_data(
+      toStringRef(data.GetData()),
+      data.GetByteOrder() == lldb::eByteOrderLittle, data.GetAddressByteSize());
+
+  if (m_is_dwo || GetVersion() >= 5)
+    return std::make_unique<llvm::DWARFDebugLoclists>(llvm_data, GetVersion());
+  return std::make_unique<llvm::DWARFDebugLoc>(llvm_data);
+}
+
+const DWARFDataExtractor &DWARFUnit::GetLocationData() const {
+  DWARFContext &Ctx = GetSymbolFileDWARF().GetDWARFContext();
+  return GetVersion() >= 5 ? Ctx.getOrLoadLocListsData()
+                           : Ctx.getOrLoadLocData();
+}
+
 void DWARFUnit::SetRangesBase(dw_addr_t ranges_base) {
   m_ranges_base = ranges_base;
+
+  if (GetVersion() < 5)
+    return;
+
+  if (auto table_or_error = ParseListTableHeader<llvm::DWARFDebugRnglistTable>(
+          m_dwarf.GetDWARFContext().getOrLoadRngListsData().GetAsLLVM(),
+          ranges_base, DWARF32))
+    m_rnglist_table = std::move(table_or_error.get());
+  else
+    GetSymbolFileDWARF().GetObjectFile()->GetModule()->ReportError(
+        "Failed to extract range list table at offset 0x%" PRIx64 ": %s",
+        ranges_base, toString(table_or_error.takeError()).c_str());
 }
 
 void DWARFUnit::SetStrOffsetsBase(dw_offset_t str_offsets_base) {
@@ -646,6 +722,8 @@ FileSpec DWARFUnit::GetFile(size_t file_idx) {
 // Remove the host part if present.
 static llvm::StringRef
 removeHostnameFromPathname(llvm::StringRef path_from_dwarf) {
+  if (!path_from_dwarf.contains(':'))
+    return path_from_dwarf;
   llvm::StringRef host, path;
   std::tie(host, path) = path_from_dwarf.split(':');
 
@@ -715,7 +793,8 @@ void DWARFUnit::ComputeAbsolutePath() {
     m_file_spec->MakeAbsolute(GetCompilationDirectory());
 }
 
-SymbolFileDWARFDwo *DWARFUnit::GetDwoSymbolFile() const {
+SymbolFileDWARFDwo *DWARFUnit::GetDwoSymbolFile() {
+  ExtractUnitDIEIfNeeded();
   return m_dwo_symbol_file.get();
 }
 
@@ -816,11 +895,12 @@ DWARFUnit::extract(SymbolFileDWARF &dwarf, user_id_t uid,
     return llvm::make_error<llvm::object::GenericBinaryError>(
         "No abbrev exists at the specified offset.");
 
+  bool is_dwo = dwarf.GetDWARFContext().isDwo();
   if (expected_header->IsTypeUnit())
-    return DWARFUnitSP(
-        new DWARFTypeUnit(dwarf, uid, *expected_header, *abbrevs, section));
-  return DWARFUnitSP(
-      new DWARFCompileUnit(dwarf, uid, *expected_header, *abbrevs, section));
+    return DWARFUnitSP(new DWARFTypeUnit(dwarf, uid, *expected_header, *abbrevs,
+                                         section, is_dwo));
+  return DWARFUnitSP(new DWARFCompileUnit(dwarf, uid, *expected_header,
+                                          *abbrevs, section, is_dwo));
 }
 
 const lldb_private::DWARFDataExtractor &DWARFUnit::GetData() const {
@@ -845,30 +925,56 @@ uint32_t DWARFUnit::GetHeaderByteSize() const {
 }
 
 llvm::Expected<DWARFRangeList>
-DWARFUnit::FindRnglistFromOffset(dw_offset_t offset) const {
-  const DWARFDebugRangesBase *debug_ranges;
-  llvm::StringRef section;
+DWARFUnit::FindRnglistFromOffset(dw_offset_t offset) {
   if (GetVersion() <= 4) {
-    debug_ranges = m_dwarf.GetDebugRanges();
-    section = "debug_ranges";
-  } else {
-    debug_ranges = m_dwarf.GetDebugRngLists();
-    section = "debug_rnglists";
+    const DWARFDebugRanges *debug_ranges = m_dwarf.GetDebugRanges();
+    if (!debug_ranges)
+      return llvm::make_error<llvm::object::GenericBinaryError>(
+          "No debug_ranges section");
+    DWARFRangeList ranges;
+    debug_ranges->FindRanges(this, offset, ranges);
+    return ranges;
   }
-  if (!debug_ranges)
-    return llvm::make_error<llvm::object::GenericBinaryError>("No " + section +
-                                                              " section");
+
+  if (!m_rnglist_table)
+    return llvm::createStringError(errc::invalid_argument,
+                                   "missing or invalid range list table");
+
+  auto range_list_or_error = m_rnglist_table->findList(
+      m_dwarf.GetDWARFContext().getOrLoadRngListsData().GetAsLLVM(), offset);
+  if (!range_list_or_error)
+    return range_list_or_error.takeError();
+
+  llvm::Expected<llvm::DWARFAddressRangesVector> llvm_ranges =
+      range_list_or_error->getAbsoluteRanges(
+          llvm::object::SectionedAddress{GetBaseAddress()},
+          [&](uint32_t index) {
+            uint32_t index_size = GetAddressByteSize();
+            dw_offset_t addr_base = GetAddrBase();
+            lldb::offset_t offset = addr_base + index * index_size;
+            return llvm::object::SectionedAddress{
+                m_dwarf.GetDWARFContext().getOrLoadAddrData().GetMaxU64(
+                    &offset, index_size)};
+          });
+  if (!llvm_ranges)
+    return llvm_ranges.takeError();
 
   DWARFRangeList ranges;
-  debug_ranges->FindRanges(this, offset, ranges);
+  for (const llvm::DWARFAddressRange &llvm_range : *llvm_ranges) {
+    ranges.Append(DWARFRangeList::Entry(llvm_range.LowPC,
+                                        llvm_range.HighPC - llvm_range.LowPC));
+  }
   return ranges;
 }
 
 llvm::Expected<DWARFRangeList>
-DWARFUnit::FindRnglistFromIndex(uint32_t index) const {
-  const DWARFDebugRngLists *debug_rnglists = m_dwarf.GetDebugRngLists();
-  if (!debug_rnglists)
-    return llvm::make_error<llvm::object::GenericBinaryError>(
-        "No debug_rnglists section");
-  return FindRnglistFromOffset(debug_rnglists->GetOffset(index));
+DWARFUnit::FindRnglistFromIndex(uint32_t index) {
+  if (llvm::Optional<uint64_t> offset = GetRnglistOffset(index))
+    return FindRnglistFromOffset(*offset);
+  if (m_rnglist_table)
+    return llvm::createStringError(errc::invalid_argument,
+                                   "invalid range list table index %d", index);
+
+  return llvm::createStringError(errc::invalid_argument,
+                                 "missing or invalid range list table");
 }
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.h b/lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.h
index 87e0de283de4..217f9bb89ace 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.h
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.h
@@ -95,8 +95,6 @@ public:
   ScopedExtractDIEs ExtractDIEsScoped();
 
   DWARFDIE LookupAddress(const dw_addr_t address);
-  size_t AppendDIEsWithTag(const dw_tag_t tag, std::vector<DWARFDIE> &dies,
-                           uint32_t depth = UINT32_MAX) const;
   bool Verify(lldb_private::Stream *s) const;
   virtual void Dump(lldb_private::Stream *s) const = 0;
   /// Get the data that contains the DIE information for this unit.
@@ -147,6 +145,7 @@ public:
   dw_addr_t GetRangesBase() const { return m_ranges_base; }
   dw_addr_t GetStrOffsetsBase() const { return m_str_offsets_base; }
   void SetAddrBase(dw_addr_t addr_base);
+  void SetLoclistsBase(dw_addr_t loclists_base);
   void SetRangesBase(dw_addr_t ranges_base);
   void SetStrOffsetsBase(dw_offset_t str_offsets_base);
   virtual void BuildAddressRangeTable(DWARFDebugAranges *debug_aranges) = 0;
@@ -202,7 +201,7 @@ public:
   lldb_private::FileSpec GetFile(size_t file_idx);
   lldb_private::FileSpec::Style GetPathStyle();
 
-  SymbolFileDWARFDwo *GetDwoSymbolFile() const;
+  SymbolFileDWARFDwo *GetDwoSymbolFile();
 
   die_iterator_range dies() {
     ExtractDIEsIfNeeded();
@@ -216,18 +215,46 @@ public:
 
   /// Return a list of address ranges resulting from a (possibly encoded)
   /// range list starting at a given offset in the appropriate ranges section.
-  llvm::Expected<DWARFRangeList> FindRnglistFromOffset(dw_offset_t offset) const;
+  llvm::Expected<DWARFRangeList> FindRnglistFromOffset(dw_offset_t offset);
 
   /// Return a list of address ranges retrieved from an encoded range
   /// list whose offset is found via a table lookup given an index (DWARF v5
   /// and later).
-  llvm::Expected<DWARFRangeList> FindRnglistFromIndex(uint32_t index) const;
+  llvm::Expected<DWARFRangeList> FindRnglistFromIndex(uint32_t index);
+
+  /// Return a rangelist's offset based on an index. The index designates
+  /// an entry in the rangelist table's offset array and is supplied by
+  /// DW_FORM_rnglistx.
+  llvm::Optional<uint64_t> GetRnglistOffset(uint32_t Index) const {
+    if (!m_rnglist_table)
+      return llvm::None;
+    if (llvm::Optional<uint64_t> off = m_rnglist_table->getOffsetEntry(Index))
+      return *off + m_ranges_base;
+    return llvm::None;
+  }
+
+  llvm::Optional<uint64_t> GetLoclistOffset(uint32_t Index) {
+    if (!m_loclist_table_header)
+      return llvm::None;
+
+    llvm::Optional<uint64_t> Offset =  m_loclist_table_header->getOffsetEntry(Index);
+    if (!Offset)
+      return llvm::None;
+    return *Offset + m_loclists_base;
+  }
+
+  /// Return the location table for parsing the given location list data. The
+  /// format is chosen according to the unit type. Never returns null.
+  std::unique_ptr<llvm::DWARFLocationTable>
+  GetLocationTable(const lldb_private::DataExtractor &data) const;
+
+  const lldb_private::DWARFDataExtractor &GetLocationData() const;
 
 protected:
   DWARFUnit(SymbolFileDWARF &dwarf, lldb::user_id_t uid,
             const DWARFUnitHeader &header,
             const DWARFAbbreviationDeclarationSet &abbrevs,
-            DIERef::Section section);
+            DIERef::Section section, bool is_dwo);
 
   llvm::Error ExtractHeader(SymbolFileDWARF &dwarf,
                             const lldb_private::DWARFDataExtractor &data,
@@ -281,14 +308,20 @@ protected:
   lldb_private::LazyBool m_is_optimized = lldb_private::eLazyBoolCalculate;
   llvm::Optional<lldb_private::FileSpec> m_comp_dir;
   llvm::Optional<lldb_private::FileSpec> m_file_spec;
-  dw_addr_t m_addr_base = 0;   // Value of DW_AT_addr_base
-  dw_addr_t m_ranges_base = 0; // Value of DW_AT_ranges_base
+  dw_addr_t m_addr_base = 0;     ///< Value of DW_AT_addr_base.
+  dw_addr_t m_loclists_base = 0; ///< Value of DW_AT_loclists_base.
+  dw_addr_t m_ranges_base = 0;   ///< Value of DW_AT_rnglists_base.
 
   /// Value of DW_AT_stmt_list.
   dw_offset_t m_line_table_offset = DW_INVALID_OFFSET;
 
   dw_offset_t m_str_offsets_base = 0; // Value of DW_AT_str_offsets_base.
+
+  llvm::Optional<llvm::DWARFDebugRnglistTable> m_rnglist_table;
+  llvm::Optional<llvm::DWARFListTableHeader> m_loclist_table_header;
+
   const DIERef::Section m_section;
+  bool m_is_dwo;
 
 private:
   void ParseProducerInfo();
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/ManualDWARFIndex.cpp b/lldb/source/Plugins/SymbolFile/DWARF/ManualDWARFIndex.cpp
index aff8b5d8c15f..1e5927bd14f0 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/ManualDWARFIndex.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/ManualDWARFIndex.cpp
@@ -401,8 +401,6 @@ void ManualDWARFIndex::GetFunctions(ConstString name, SymbolFileDWARF &dwarf,
 
   if (name_type_mask & eFunctionNameTypeFull) {
     DIEArray offsets;
-    m_set.function_basenames.Find(name, offsets);
-    m_set.function_methods.Find(name, offsets);
     m_set.function_fullnames.Find(name, offsets);
     for (const DIERef &die_ref: offsets) {
       DWARFDIE die = dwarf.GetDIE(die_ref);
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
index c982d59c2830..d45a8b56efe4 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
@@ -94,6 +94,8 @@
 using namespace lldb;
 using namespace lldb_private;
 
+char SymbolFileDWARF::ID;
+
 // static inline bool
 // child_requires_parent_class_union_or_struct_to_be_completed (dw_tag_t tag)
 //{
@@ -179,36 +181,46 @@ ParseLLVMLineTable(lldb_private::DWARFContext &context,
   return *line_table;
 }
 
-static FileSpecList ParseSupportFilesFromPrologue(
-    const lldb::ModuleSP &module,
-    const llvm::DWARFDebugLine::Prologue &prologue, FileSpec::Style style,
-    llvm::StringRef compile_dir = {}, FileSpec first_file = {}) {
+static llvm::Optional<std::string>
+GetFileByIndex(const llvm::DWARFDebugLine::Prologue &prologue, size_t idx,
+               llvm::StringRef compile_dir, FileSpec::Style style) {
+  // Try to get an absolute path first.
+  std::string abs_path;
+  auto absolute = llvm::DILineInfoSpecifier::FileLineInfoKind::AbsoluteFilePath;
+  if (prologue.getFileNameByIndex(idx, compile_dir, absolute, abs_path, style))
+    return std::move(abs_path);
+
+  // Otherwise ask for a relative path.
+  std::string rel_path;
+  auto relative = llvm::DILineInfoSpecifier::FileLineInfoKind::Default;
+  if (!prologue.getFileNameByIndex(idx, compile_dir, relative, rel_path, style))
+    return {};
+  return std::move(rel_path);
+}
+
+static FileSpecList
+ParseSupportFilesFromPrologue(const lldb::ModuleSP &module,
+                              const llvm::DWARFDebugLine::Prologue &prologue,
+                              FileSpec::Style style,
+                              llvm::StringRef compile_dir = {}) {
   FileSpecList support_files;
-  support_files.Append(first_file);
+  size_t first_file = 0;
+  if (prologue.getVersion() <= 4) {
+    // File index 0 is not valid before DWARF v5. Add a dummy entry to ensure
+    // support file list indices match those we get from the debug info and line
+    // tables.
+    support_files.Append(FileSpec());
+    first_file = 1;
+  }
 
   const size_t number_of_files = prologue.FileNames.size();
-  for (size_t idx = 1; idx <= number_of_files; ++idx) {
-    std::string original_file;
-    if (!prologue.getFileNameByIndex(
-            idx, compile_dir,
-            llvm::DILineInfoSpecifier::FileLineInfoKind::Default, original_file,
-            style)) {
-      // Always add an entry so the indexes remain correct.
-      support_files.EmplaceBack();
-      continue;
-    }
-
+  for (size_t idx = first_file; idx <= number_of_files; ++idx) {
     std::string remapped_file;
-    if (!prologue.getFileNameByIndex(
-            idx, compile_dir,
-            llvm::DILineInfoSpecifier::FileLineInfoKind::AbsoluteFilePath,
-            remapped_file, style)) {
-      // Always add an entry so the indexes remain correct.
-      support_files.EmplaceBack(original_file, style);
-      continue;
-    }
+    if (auto file_path = GetFileByIndex(prologue, idx, compile_dir, style))
+      if (!module->RemapSourceFile(llvm::StringRef(*file_path), remapped_file))
+        remapped_file = std::move(*file_path);
 
-    module->RemapSourceFile(llvm::StringRef(original_file), remapped_file);
+    // Unconditionally add an entry, so the indices match up.
     support_files.EmplaceBack(remapped_file, style);
   }
 
@@ -585,22 +597,6 @@ void SymbolFileDWARF::LoadSectionData(lldb::SectionType sect_type,
   m_objfile_sp->ReadSectionData(section_sp.get(), data);
 }
 
-const DWARFDataExtractor &SymbolFileDWARF::DebugLocData() {
-  const DWARFDataExtractor &debugLocData = get_debug_loc_data();
-  if (debugLocData.GetByteSize() > 0)
-    return debugLocData;
-  return get_debug_loclists_data();
-}
-
-const DWARFDataExtractor &SymbolFileDWARF::get_debug_loc_data() {
-  return GetCachedSectionData(eSectionTypeDWARFDebugLoc, m_data_debug_loc);
-}
-
-const DWARFDataExtractor &SymbolFileDWARF::get_debug_loclists_data() {
-  return GetCachedSectionData(eSectionTypeDWARFDebugLocLists,
-                              m_data_debug_loclists);
-}
-
 DWARFDebugAbbrev *SymbolFileDWARF::DebugAbbrev() {
   if (m_abbr)
     return m_abbr.get();
@@ -672,21 +668,6 @@ DWARFDebugRanges *SymbolFileDWARF::GetDebugRanges() {
   return m_ranges.get();
 }
 
-DWARFDebugRngLists *SymbolFileDWARF::GetDebugRngLists() {
-  if (!m_rnglists) {
-    static Timer::Category func_cat(LLVM_PRETTY_FUNCTION);
-    Timer scoped_timer(func_cat, "%s this = %p", LLVM_PRETTY_FUNCTION,
-                       static_cast<void *>(this));
-
-    if (m_context.getOrLoadRngListsData().GetByteSize() > 0)
-      m_rnglists.reset(new DWARFDebugRngLists());
-
-    if (m_rnglists)
-      m_rnglists->Extract(m_context);
-  }
-  return m_rnglists.get();
-}
-
 lldb::CompUnitSP SymbolFileDWARF::ParseCompileUnit(DWARFCompileUnit &dwarf_cu) {
   CompUnitSP cu_sp;
   CompileUnit *comp_unit = (CompileUnit *)dwarf_cu.GetUserData();
@@ -703,7 +684,8 @@ lldb::CompUnitSP SymbolFileDWARF::ParseCompileUnit(DWARFCompileUnit &dwarf_cu) {
     } else {
       ModuleSP module_sp(m_objfile_sp->GetModule());
       if (module_sp) {
-        const DWARFDIE cu_die = dwarf_cu.DIE();
+        const DWARFBaseDIE cu_die =
+            dwarf_cu.GetNonSkeletonUnit().GetUnitDIEOnly();
         if (cu_die) {
           FileSpec cu_file_spec(cu_die.GetName(), dwarf_cu.GetPathStyle());
           if (cu_file_spec) {
@@ -721,7 +703,7 @@ lldb::CompUnitSP SymbolFileDWARF::ParseCompileUnit(DWARFCompileUnit &dwarf_cu) {
           LanguageType cu_language = DWARFUnit::LanguageTypeFromDWARF(
               cu_die.GetAttributeValueAsUnsigned(DW_AT_language, 0));
 
-          bool is_optimized = dwarf_cu.GetIsOptimized();
+          bool is_optimized = dwarf_cu.GetNonSkeletonUnit().GetIsOptimized();
           BuildCuTranslationTable();
           cu_sp = std::make_shared<CompileUnit>(
               module_sp, &dwarf_cu, cu_file_spec,
@@ -828,15 +810,20 @@ lldb::LanguageType SymbolFileDWARF::ParseLanguage(CompileUnit &comp_unit) {
 }
 
 size_t SymbolFileDWARF::ParseFunctions(CompileUnit &comp_unit) {
+  static Timer::Category func_cat(LLVM_PRETTY_FUNCTION);
+  Timer scoped_timer(func_cat, "SymbolFileDWARF::ParseFunctions");
   std::lock_guard<std::recursive_mutex> guard(GetModuleMutex());
   DWARFUnit *dwarf_cu = GetDWARFCompileUnit(&comp_unit);
   if (!dwarf_cu)
     return 0;
 
   size_t functions_added = 0;
-  std::vector<DWARFDIE> function_dies;
-  dwarf_cu->AppendDIEsWithTag(DW_TAG_subprogram, function_dies);
-  for (const DWARFDIE &die : function_dies) {
+  dwarf_cu = &dwarf_cu->GetNonSkeletonUnit();
+  for (DWARFDebugInfoEntry &entry : dwarf_cu->dies()) {
+    if (entry.Tag() != DW_TAG_subprogram)
+      continue;
+
+    DWARFDIE die(dwarf_cu, &entry);
     if (comp_unit.FindFunctionByUID(die.GetID()))
       continue;
     if (ParseFunction(comp_unit, die))
@@ -846,16 +833,32 @@ size_t SymbolFileDWARF::ParseFunctions(CompileUnit &comp_unit) {
   return functions_added;
 }
 
-void SymbolFileDWARF::ForEachExternalModule(
-    CompileUnit &comp_unit, llvm::function_ref<void(ModuleSP)> f) {
-  UpdateExternalModuleListIfNeeded();
+bool SymbolFileDWARF::ForEachExternalModule(
+    CompileUnit &comp_unit,
+    llvm::DenseSet<lldb_private::SymbolFile *> &visited_symbol_files,
+    llvm::function_ref<bool(Module &)> lambda) {
+  // Only visit each symbol file once.
+  if (!visited_symbol_files.insert(this).second)
+    return false;
 
+  UpdateExternalModuleListIfNeeded();
   for (auto &p : m_external_type_modules) {
     ModuleSP module = p.second;
-    f(module);
-    for (std::size_t i = 0; i < module->GetNumCompileUnits(); ++i)
-      module->GetCompileUnitAtIndex(i)->ForEachExternalModule(f);
+    if (!module)
+      continue;
+
+    // Invoke the action and potentially early-exit.
+    if (lambda(*module))
+      return true;
+
+    for (std::size_t i = 0; i < module->GetNumCompileUnits(); ++i) {
+      auto cu = module->GetCompileUnitAtIndex(i);
+      bool early_exit = cu->ForEachExternalModule(visited_symbol_files, lambda);
+      if (early_exit)
+        return true;
+    }
   }
+  return false;
 }
 
 bool SymbolFileDWARF::ParseSupportFiles(CompileUnit &comp_unit,
@@ -961,7 +964,7 @@ bool SymbolFileDWARF::ParseImportedModules(
               DW_AT_LLVM_include_path, nullptr))
         module.search_path = ConstString(include_path);
       if (const char *sysroot = module_die.GetAttributeValueAsString(
-              DW_AT_LLVM_isysroot, nullptr))
+              DW_AT_LLVM_sysroot, nullptr))
         module.sysroot = ConstString(sysroot);
       imported_modules.push_back(module);
     }
@@ -1023,7 +1026,7 @@ bool SymbolFileDWARF::ParseLineTable(CompileUnit &comp_unit) {
 
   comp_unit.SetSupportFiles(ParseSupportFilesFromPrologue(
       comp_unit.GetModule(), line_table->Prologue, dwarf_cu->GetPathStyle(),
-      dwarf_cu->GetCompilationDirectory().GetCString(), FileSpec(comp_unit)));
+      dwarf_cu->GetCompilationDirectory().GetCString()));
 
   return true;
 }
@@ -1507,7 +1510,7 @@ bool SymbolFileDWARF::GetFunction(const DWARFDIE &die, SymbolContext &sc) {
   return false;
 }
 
-lldb::ModuleSP SymbolFileDWARF::GetDWOModule(ConstString name) {
+lldb::ModuleSP SymbolFileDWARF::GetExternalModule(ConstString name) {
   UpdateExternalModuleListIfNeeded();
   const auto &pos = m_external_type_modules.find(name);
   if (pos != m_external_type_modules.end())
@@ -1532,12 +1535,48 @@ SymbolFileDWARF::GetDIE(const DIERef &die_ref) {
     return DWARFDIE();
 }
 
+/// Return the DW_AT_(GNU_)dwo_name.
+static const char *GetDWOName(DWARFCompileUnit &dwarf_cu,
+                              const DWARFDebugInfoEntry &cu_die) {
+  const char *dwo_name =
+      cu_die.GetAttributeValueAsString(&dwarf_cu, DW_AT_GNU_dwo_name, nullptr);
+  if (!dwo_name)
+    dwo_name =
+        cu_die.GetAttributeValueAsString(&dwarf_cu, DW_AT_dwo_name, nullptr);
+  return dwo_name;
+}
+
+/// Return the DW_AT_(GNU_)dwo_id.
+/// FIXME: Technically 0 is a valid hash.
+static uint64_t GetDWOId(DWARFCompileUnit &dwarf_cu,
+                         const DWARFDebugInfoEntry &cu_die) {
+  uint64_t dwo_id =
+      cu_die.GetAttributeValueAsUnsigned(&dwarf_cu, DW_AT_GNU_dwo_id, 0);
+  if (!dwo_id)
+    dwo_id = cu_die.GetAttributeValueAsUnsigned(&dwarf_cu, DW_AT_dwo_id, 0);
+  return dwo_id;
+}
+
+llvm::Optional<uint64_t> SymbolFileDWARF::GetDWOId() {
+  if (GetNumCompileUnits() == 1) {
+    if (auto comp_unit = GetCompileUnitAtIndex(0))
+      if (DWARFCompileUnit *cu = llvm::dyn_cast_or_null<DWARFCompileUnit>(
+              GetDWARFCompileUnit(comp_unit.get())))
+        if (DWARFDebugInfoEntry *cu_die = cu->DIE().GetDIE())
+          if (uint64_t dwo_id = ::GetDWOId(*cu, *cu_die))
+            return dwo_id;
+  }
+  return {};
+}
+
 std::unique_ptr<SymbolFileDWARFDwo>
 SymbolFileDWARF::GetDwoSymbolFileForCompileUnit(
     DWARFUnit &unit, const DWARFDebugInfoEntry &cu_die) {
-  // If we are using a dSYM file, we never want the standard DWO files since
-  // the -gmodules support uses the same DWO machanism to specify full debug
-  // info files for modules.
+  // If this is a Darwin-style debug map (non-.dSYM) symbol file,
+  // never attempt to load ELF-style DWO files since the -gmodules
+  // support uses the same DWO machanism to specify full debug info
+  // files for modules. This is handled in
+  // UpdateExternalModuleListIfNeeded().
   if (GetDebugMapSymfile())
     return nullptr;
 
@@ -1546,15 +1585,13 @@ SymbolFileDWARF::GetDwoSymbolFileForCompileUnit(
   if (!dwarf_cu)
     return nullptr;
 
-  const char *dwo_name =
-      cu_die.GetAttributeValueAsString(dwarf_cu, DW_AT_GNU_dwo_name, nullptr);
+  const char *dwo_name = GetDWOName(*dwarf_cu, cu_die);
   if (!dwo_name)
     return nullptr;
 
   SymbolFileDWARFDwp *dwp_symfile = GetDwpSymbolFile();
   if (dwp_symfile) {
-    uint64_t dwo_id =
-        cu_die.GetAttributeValueAsUnsigned(dwarf_cu, DW_AT_GNU_dwo_id, 0);
+    uint64_t dwo_id = ::GetDWOId(*dwarf_cu, cu_die);
     std::unique_ptr<SymbolFileDWARFDwo> dwo_symfile =
         dwp_symfile->GetSymbolFileForDwoId(*dwarf_cu, dwo_id);
     if (dwo_symfile)
@@ -1594,76 +1631,101 @@ void SymbolFileDWARF::UpdateExternalModuleListIfNeeded() {
   if (m_fetched_external_modules)
     return;
   m_fetched_external_modules = true;
-
   DWARFDebugInfo *debug_info = DebugInfo();
 
+  // Follow DWO skeleton unit breadcrumbs.
   const uint32_t num_compile_units = GetNumCompileUnits();
   for (uint32_t cu_idx = 0; cu_idx < num_compile_units; ++cu_idx) {
-    DWARFUnit *dwarf_cu = debug_info->GetUnitAtIndex(cu_idx);
+    auto *dwarf_cu =
+        llvm::dyn_cast<DWARFCompileUnit>(debug_info->GetUnitAtIndex(cu_idx));
+    if (!dwarf_cu)
+      continue;
 
     const DWARFBaseDIE die = dwarf_cu->GetUnitDIEOnly();
-    if (die && !die.HasChildren()) {
-      const char *name = die.GetAttributeValueAsString(DW_AT_name, nullptr);
-
-      if (name) {
-        ConstString const_name(name);
-        if (m_external_type_modules.find(const_name) ==
-            m_external_type_modules.end()) {
-          ModuleSP module_sp;
-          const char *dwo_path =
-              die.GetAttributeValueAsString(DW_AT_GNU_dwo_name, nullptr);
-          if (dwo_path) {
-            ModuleSpec dwo_module_spec;
-            dwo_module_spec.GetFileSpec().SetFile(dwo_path,
-                                                  FileSpec::Style::native);
-            if (dwo_module_spec.GetFileSpec().IsRelative()) {
-              const char *comp_dir =
-                  die.GetAttributeValueAsString(DW_AT_comp_dir, nullptr);
-              if (comp_dir) {
-                dwo_module_spec.GetFileSpec().SetFile(comp_dir,
-                                                      FileSpec::Style::native);
-                FileSystem::Instance().Resolve(dwo_module_spec.GetFileSpec());
-                dwo_module_spec.GetFileSpec().AppendPathComponent(dwo_path);
-              }
-            }
-            dwo_module_spec.GetArchitecture() =
-                m_objfile_sp->GetModule()->GetArchitecture();
-
-            // When LLDB loads "external" modules it looks at the presence of
-            // DW_AT_GNU_dwo_name. However, when the already created module
-            // (corresponding to .dwo itself) is being processed, it will see
-            // the presence of DW_AT_GNU_dwo_name (which contains the name of
-            // dwo file) and will try to call ModuleList::GetSharedModule
-            // again. In some cases (i.e. for empty files) Clang 4.0 generates
-            // a *.dwo file which has DW_AT_GNU_dwo_name, but no
-            // DW_AT_comp_dir. In this case the method
-            // ModuleList::GetSharedModule will fail and the warning will be
-            // printed. However, as one can notice in this case we don't
-            // actually need to try to load the already loaded module
-            // (corresponding to .dwo) so we simply skip it.
-            if (m_objfile_sp->GetFileSpec().GetFileNameExtension() == ".dwo" &&
-                llvm::StringRef(m_objfile_sp->GetFileSpec().GetPath())
-                    .endswith(dwo_module_spec.GetFileSpec().GetPath())) {
-              continue;
-            }
+    if (!die || die.HasChildren() || !die.GetDIE())
+      continue;
 
-            Status error = ModuleList::GetSharedModule(
-                dwo_module_spec, module_sp, nullptr, nullptr, nullptr);
-            if (!module_sp) {
-              GetObjectFile()->GetModule()->ReportWarning(
-                  "0x%8.8x: unable to locate module needed for external types: "
-                  "%s\nerror: %s\nDebugging will be degraded due to missing "
-                  "types. Rebuilding your project will regenerate the needed "
-                  "module files.",
-                  die.GetOffset(),
-                  dwo_module_spec.GetFileSpec().GetPath().c_str(),
-                  error.AsCString("unknown error"));
-            }
-          }
-          m_external_type_modules[const_name] = module_sp;
-        }
+    const char *name = die.GetAttributeValueAsString(DW_AT_name, nullptr);
+    if (!name)
+      continue;
+
+    ConstString const_name(name);
+    ModuleSP &module_sp = m_external_type_modules[const_name];
+    if (module_sp)
+      continue;
+
+    const char *dwo_path = GetDWOName(*dwarf_cu, *die.GetDIE());
+    if (!dwo_path)
+      continue;
+
+    ModuleSpec dwo_module_spec;
+    dwo_module_spec.GetFileSpec().SetFile(dwo_path, FileSpec::Style::native);
+    if (dwo_module_spec.GetFileSpec().IsRelative()) {
+      const char *comp_dir =
+          die.GetAttributeValueAsString(DW_AT_comp_dir, nullptr);
+      if (comp_dir) {
+        dwo_module_spec.GetFileSpec().SetFile(comp_dir,
+                                              FileSpec::Style::native);
+        FileSystem::Instance().Resolve(dwo_module_spec.GetFileSpec());
+        dwo_module_spec.GetFileSpec().AppendPathComponent(dwo_path);
       }
     }
+    dwo_module_spec.GetArchitecture() =
+        m_objfile_sp->GetModule()->GetArchitecture();
+
+    // When LLDB loads "external" modules it looks at the presence of
+    // DW_AT_dwo_name. However, when the already created module
+    // (corresponding to .dwo itself) is being processed, it will see
+    // the presence of DW_AT_dwo_name (which contains the name of dwo
+    // file) and will try to call ModuleList::GetSharedModule
+    // again. In some cases (i.e., for empty files) Clang 4.0
+    // generates a *.dwo file which has DW_AT_dwo_name, but no
+    // DW_AT_comp_dir. In this case the method
+    // ModuleList::GetSharedModule will fail and the warning will be
+    // printed. However, as one can notice in this case we don't
+    // actually need to try to load the already loaded module
+    // (corresponding to .dwo) so we simply skip it.
+    if (m_objfile_sp->GetFileSpec().GetFileNameExtension() == ".dwo" &&
+        llvm::StringRef(m_objfile_sp->GetFileSpec().GetPath())
+            .endswith(dwo_module_spec.GetFileSpec().GetPath())) {
+      continue;
+    }
+
+    Status error = ModuleList::GetSharedModule(dwo_module_spec, module_sp,
+                                               nullptr, nullptr, nullptr);
+    if (!module_sp) {
+      GetObjectFile()->GetModule()->ReportWarning(
+          "0x%8.8x: unable to locate module needed for external types: "
+          "%s\nerror: %s\nDebugging will be degraded due to missing "
+          "types. Rebuilding the project will regenerate the needed "
+          "module files.",
+          die.GetOffset(), dwo_module_spec.GetFileSpec().GetPath().c_str(),
+          error.AsCString("unknown error"));
+      continue;
+    }
+
+    // Verify the DWO hash.
+    // FIXME: Technically "0" is a valid hash.
+    uint64_t dwo_id = ::GetDWOId(*dwarf_cu, *die.GetDIE());
+    if (!dwo_id)
+      continue;
+
+    auto *dwo_symfile =
+        llvm::dyn_cast_or_null<SymbolFileDWARF>(module_sp->GetSymbolFile());
+    if (!dwo_symfile)
+      continue;
+    llvm::Optional<uint64_t> dwo_dwo_id = dwo_symfile->GetDWOId();
+    if (!dwo_dwo_id)
+      continue;
+
+    if (dwo_id != dwo_dwo_id) {
+      GetObjectFile()->GetModule()->ReportWarning(
+          "0x%8.8x: Module %s is out-of-date (hash mismatch). Type information "
+          "from this module may be incomplete or inconsistent with the rest of "
+          "the program. Rebuilding the project will regenerate the needed "
+          "module files.",
+          die.GetOffset(), dwo_module_spec.GetFileSpec().GetPath().c_str());
+    }
   }
 }
 
@@ -1867,9 +1929,8 @@ uint32_t SymbolFileDWARF::ResolveSymbolContext(const FileSpec &file_spec,
       if (!dc_cu)
         continue;
 
-      const bool full_match = (bool)file_spec.GetDirectory();
       bool file_spec_matches_cu_file_spec =
-          FileSpec::Equal(file_spec, *dc_cu, full_match);
+          FileSpec::Match(file_spec, dc_cu->GetPrimaryFile());
       if (check_inlines || file_spec_matches_cu_file_spec) {
         SymbolContext sc(m_objfile_sp->GetModule());
         sc.comp_unit = dc_cu;
@@ -2208,9 +2269,12 @@ bool SymbolFileDWARF::ResolveFunction(const DWARFDIE &orig_die,
       addr = sc.function->GetAddressRange().GetBaseAddress();
     }
 
-    if (addr.IsValid()) {
-      sc_list.Append(sc);
-      return true;
+
+    if (auto section_sp = addr.GetSection()) {
+      if (section_sp->GetPermissions() & ePermissionsExecutable) {
+        sc_list.Append(sc);
+        return true;
+      }
     }
   }
 
@@ -2364,12 +2428,10 @@ void SymbolFileDWARF::FindTypes(
     llvm::DenseSet<lldb_private::SymbolFile *> &searched_symbol_files,
     TypeMap &types) {
   std::lock_guard<std::recursive_mutex> guard(GetModuleMutex());
-  // Make sure we haven't already searched this SymbolFile before...
-  if (searched_symbol_files.count(this))
+  // Make sure we haven't already searched this SymbolFile before.
+  if (!searched_symbol_files.insert(this).second)
     return;
 
-  searched_symbol_files.insert(this);
-
   DWARFDebugInfo *info = DebugInfo();
   if (!info)
     return;
@@ -2451,8 +2513,13 @@ void SymbolFileDWARF::FindTypes(
   }
 }
 
-void SymbolFileDWARF::FindTypes(llvm::ArrayRef<CompilerContext> pattern,
-                                  LanguageSet languages, TypeMap &types) {
+void SymbolFileDWARF::FindTypes(
+    llvm::ArrayRef<CompilerContext> pattern, LanguageSet languages,
+    llvm::DenseSet<SymbolFile *> &searched_symbol_files, TypeMap &types) {
+  // Make sure we haven't already searched this SymbolFile before.
+  if (!searched_symbol_files.insert(this).second)
+    return;
+
   std::lock_guard<std::recursive_mutex> guard(GetModuleMutex());
   if (pattern.empty())
     return;
@@ -2482,11 +2549,22 @@ void SymbolFileDWARF::FindTypes(llvm::ArrayRef<CompilerContext> pattern,
     if (!contextMatches(die_context, pattern))
       continue;
 
-    if (Type *matching_type = ResolveType(die, true, true))
+    if (Type *matching_type = ResolveType(die, true, true)) {
       // We found a type pointer, now find the shared pointer form our type
       // list.
       types.InsertUnique(matching_type->shared_from_this());
+    }
   }
+
+  // Next search through the reachable Clang modules. This only applies for
+  // DWARF objects compiled with -gmodules that haven't been processed by
+  // dsymutil.
+  UpdateExternalModuleListIfNeeded();
+
+  for (const auto &pair : m_external_type_modules)
+    if (ModuleSP external_module_sp = pair.second)
+      external_module_sp->FindTypes(pattern, languages, searched_symbol_files,
+                                    types);
 }
 
 CompilerDeclContext
@@ -3268,15 +3346,17 @@ VariableSP SymbolFileDWARF::ParseVariableDIE(const SymbolContext &sc,
                   module, DataExtractor(data, block_offset, block_length),
                   die.GetCU());
             } else {
-              DataExtractor data = DebugLocData();
-              const dw_offset_t offset = form_value.Unsigned();
+              DataExtractor data = die.GetCU()->GetLocationData();
+              dw_offset_t offset = form_value.Unsigned();
+              if (form_value.Form() == DW_FORM_loclistx)
+                offset = die.GetCU()->GetLoclistOffset(offset).getValueOr(-1);
               if (data.ValidOffset(offset)) {
                 data = DataExtractor(data, offset, data.GetByteSize() - offset);
                 location = DWARFExpression(module, data, die.GetCU());
                 assert(func_low_pc != LLDB_INVALID_ADDRESS);
-                location.SetLocationListSlide(
-                    func_low_pc -
-                    attributes.CompileUnitAtIndex(i)->GetBaseAddress());
+                location.SetLocationListAddresses(
+                    attributes.CompileUnitAtIndex(i)->GetBaseAddress(),
+                    func_low_pc);
               }
             }
           } break;
@@ -3685,8 +3765,8 @@ CollectCallSiteParameters(ModuleSP module, DWARFDIE call_site_die) {
     if (child.Tag() != DW_TAG_call_site_parameter)
       continue;
 
-    llvm::Optional<DWARFExpression> LocationInCallee = {};
-    llvm::Optional<DWARFExpression> LocationInCaller = {};
+    llvm::Optional<DWARFExpression> LocationInCallee;
+    llvm::Optional<DWARFExpression> LocationInCaller;
 
     DWARFAttributes attributes;
     const size_t num_attributes = child.GetAttributes(attributes);
@@ -3725,7 +3805,7 @@ CollectCallSiteParameters(ModuleSP module, DWARFDIE call_site_die) {
 }
 
 /// Collect call graph edges present in a function DIE.
-static std::vector<lldb_private::CallEdge>
+static std::vector<std::unique_ptr<lldb_private::CallEdge>>
 CollectCallEdges(ModuleSP module, DWARFDIE function_die) {
   // Check if the function has a supported call site-related attribute.
   // TODO: In the future it may be worthwhile to support call_all_source_calls.
@@ -3743,32 +3823,87 @@ CollectCallEdges(ModuleSP module, DWARFDIE function_die) {
   // to be DWARF5-compliant. This may need to be done lazily to be performant.
   // For now, assume that all entries are nested directly under the subprogram
   // (this is the kind of DWARF LLVM produces) and parse them eagerly.
-  std::vector<CallEdge> call_edges;
+  std::vector<std::unique_ptr<CallEdge>> call_edges;
   for (DWARFDIE child = function_die.GetFirstChild(); child.IsValid();
        child = child.GetSibling()) {
     if (child.Tag() != DW_TAG_call_site)
       continue;
 
-    // Extract DW_AT_call_origin (the call target's DIE).
-    DWARFDIE call_origin = child.GetReferencedDIE(DW_AT_call_origin);
-    if (!call_origin.IsValid()) {
-      LLDB_LOG(log, "CollectCallEdges: Invalid call origin in {0}",
-               function_die.GetPubname());
+    llvm::Optional<DWARFDIE> call_origin;
+    llvm::Optional<DWARFExpression> call_target;
+    addr_t return_pc = LLDB_INVALID_ADDRESS;
+
+    DWARFAttributes attributes;
+    const size_t num_attributes = child.GetAttributes(attributes);
+    for (size_t i = 0; i < num_attributes; ++i) {
+      DWARFFormValue form_value;
+      if (!attributes.ExtractFormValueAtIndex(i, form_value)) {
+        LLDB_LOG(log, "CollectCallEdges: Could not extract TAG_call_site form");
+        break;
+      }
+
+      dw_attr_t attr = attributes.AttributeAtIndex(i);
+
+      // Extract DW_AT_call_origin (the call target's DIE).
+      if (attr == DW_AT_call_origin) {
+        call_origin = form_value.Reference();
+        if (!call_origin->IsValid()) {
+          LLDB_LOG(log, "CollectCallEdges: Invalid call origin in {0}",
+                   function_die.GetPubname());
+          break;
+        }
+      }
+
+      // Extract DW_AT_call_return_pc (the PC the call returns to) if it's
+      // available. It should only ever be unavailable for tail call edges, in
+      // which case use LLDB_INVALID_ADDRESS.
+      if (attr == DW_AT_call_return_pc)
+        return_pc = form_value.Address();
+
+      // Extract DW_AT_call_target (the location of the address of the indirect
+      // call).
+      if (attr == DW_AT_call_target) {
+        if (!DWARFFormValue::IsBlockForm(form_value.Form())) {
+          LLDB_LOG(log,
+                   "CollectCallEdges: AT_call_target does not have block form");
+          break;
+        }
+
+        auto data = child.GetData();
+        uint32_t block_offset = form_value.BlockData() - data.GetDataStart();
+        uint32_t block_length = form_value.Unsigned();
+        call_target = DWARFExpression(
+            module, DataExtractor(data, block_offset, block_length),
+            child.GetCU());
+      }
+    }
+    if (!call_origin && !call_target) {
+      LLDB_LOG(log, "CollectCallEdges: call site without any call target");
       continue;
     }
 
-    // Extract DW_AT_call_return_pc (the PC the call returns to) if it's
-    // available. It should only ever be unavailable for tail call edges, in
-    // which case use LLDB_INVALID_ADDRESS.
-    addr_t return_pc = child.GetAttributeValueAsAddress(DW_AT_call_return_pc,
-                                                        LLDB_INVALID_ADDRESS);
-
     // Extract call site parameters.
     CallSiteParameterArray parameters =
         CollectCallSiteParameters(module, child);
 
-    LLDB_LOG(log, "CollectCallEdges: Found call origin: {0} (retn-PC: {1:x})",
-             call_origin.GetPubname(), return_pc);
+    std::unique_ptr<CallEdge> edge;
+    if (call_origin) {
+      LLDB_LOG(log, "CollectCallEdges: Found call origin: {0} (retn-PC: {1:x})",
+               call_origin->GetPubname(), return_pc);
+      edge = std::make_unique<DirectCallEdge>(call_origin->GetMangledName(),
+                                              return_pc, std::move(parameters));
+    } else {
+      if (log) {
+        StreamString call_target_desc;
+        call_target->GetDescription(&call_target_desc, eDescriptionLevelBrief,
+                                    LLDB_INVALID_ADDRESS, nullptr);
+        LLDB_LOG(log, "CollectCallEdges: Found indirect call target: {0}",
+                 call_target_desc.GetString());
+      }
+      edge = std::make_unique<IndirectCallEdge>(*call_target, return_pc,
+                                                std::move(parameters));
+    }
+
     if (log && parameters.size()) {
       for (const CallSiteParameter &param : parameters) {
         StreamString callee_loc_desc, caller_loc_desc;
@@ -3783,13 +3918,12 @@ CollectCallEdges(ModuleSP module, DWARFDIE function_die) {
       }
     }
 
-    call_edges.emplace_back(call_origin.GetMangledName(), return_pc,
-                            std::move(parameters));
+    call_edges.push_back(std::move(edge));
   }
   return call_edges;
 }
 
-std::vector<lldb_private::CallEdge>
+std::vector<std::unique_ptr<lldb_private::CallEdge>>
 SymbolFileDWARF::ParseCallEdgesInFunction(UserID func_id) {
   DWARFDIE func_die = GetDIE(func_id.GetID());
   if (func_die.IsValid())
@@ -3829,13 +3963,6 @@ SymbolFileDWARFDebugMap *SymbolFileDWARF::GetDebugMapSymfile() {
   return m_debug_map_symfile;
 }
 
-DWARFExpression::LocationListFormat
-SymbolFileDWARF::GetLocationListFormat() const {
-  if (m_data_debug_loclists.m_data.GetByteSize() > 0)
-    return DWARFExpression::LocLists;
-  return DWARFExpression::RegularLocationList;
-}
-
 SymbolFileDWARFDwp *SymbolFileDWARF::GetDwpSymbolFile() {
   llvm::call_once(m_dwp_symfile_once_flag, [this]() {
     ModuleSpec module_spec;
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.h b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.h
index 04cb11d426be..23e26732453f 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.h
+++ b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.h
@@ -21,7 +21,6 @@
 
 #include "lldb/Core/UniqueCStringMap.h"
 #include "lldb/Core/dwarf.h"
-#include "lldb/Expression/DWARFExpression.h"
 #include "lldb/Symbol/DebugMacros.h"
 #include "lldb/Symbol/SymbolContext.h"
 #include "lldb/Symbol/SymbolFile.h"
@@ -47,7 +46,6 @@ class DWARFDebugInfo;
 class DWARFDebugInfoEntry;
 class DWARFDebugLine;
 class DWARFDebugRanges;
-class DWARFDebugRngLists;
 class DWARFDeclContext;
 class DWARFFormValue;
 class DWARFTypeUnit;
@@ -59,7 +57,18 @@ class SymbolFileDWARFDwp;
 
 class SymbolFileDWARF : public lldb_private::SymbolFile,
                         public lldb_private::UserID {
+  /// LLVM RTTI support.
+  static char ID;
+
 public:
+  /// LLVM RTTI support.
+  /// \{
+  bool isA(const void *ClassID) const override {
+    return ClassID == &ID || SymbolFile::isA(ClassID);
+  }
+  static bool classof(const SymbolFile *obj) { return obj->isA(&ID); }
+  /// \}
+
   friend class SymbolFileDWARFDebugMap;
   friend class SymbolFileDWARFDwo;
   friend class DebugMapModule;
@@ -105,9 +114,9 @@ public:
 
   bool ParseDebugMacros(lldb_private::CompileUnit &comp_unit) override;
 
-  void
-  ForEachExternalModule(lldb_private::CompileUnit &comp_unit,
-                        llvm::function_ref<void(lldb::ModuleSP)> f) override;
+  bool ForEachExternalModule(
+      lldb_private::CompileUnit &, llvm::DenseSet<lldb_private::SymbolFile *> &,
+      llvm::function_ref<bool(lldb_private::Module &)>) override;
 
   bool ParseSupportFiles(lldb_private::CompileUnit &comp_unit,
                          lldb_private::FileSpecList &support_files) override;
@@ -190,6 +199,7 @@ public:
 
   void FindTypes(llvm::ArrayRef<lldb_private::CompilerContext> pattern,
                  lldb_private::LanguageSet languages,
+                 llvm::DenseSet<SymbolFile *> &searched_symbol_files,
                  lldb_private::TypeMap &types) override;
 
   void GetTypes(lldb_private::SymbolContextScope *sc_scope,
@@ -212,9 +222,6 @@ public:
 
   uint32_t GetPluginVersion() override;
 
-  const lldb_private::DWARFDataExtractor &get_debug_loc_data();
-  const lldb_private::DWARFDataExtractor &get_debug_loclists_data();
-
   DWARFDebugAbbrev *DebugAbbrev();
 
   const DWARFDebugAbbrev *DebugAbbrev() const;
@@ -224,9 +231,6 @@ public:
   const DWARFDebugInfo *DebugInfo() const;
 
   DWARFDebugRanges *GetDebugRanges();
-  DWARFDebugRngLists *GetDebugRngLists();
-
-  const lldb_private::DWARFDataExtractor &DebugLocData();
 
   static bool SupportedVersion(uint16_t version);
 
@@ -250,10 +254,7 @@ public:
 
   virtual lldb::CompUnitSP ParseCompileUnit(DWARFCompileUnit &dwarf_cu);
 
-  virtual lldb_private::DWARFExpression::LocationListFormat
-  GetLocationListFormat() const;
-
-  lldb::ModuleSP GetDWOModule(lldb_private::ConstString name);
+  lldb::ModuleSP GetExternalModule(lldb_private::ConstString name);
 
   typedef std::map<lldb_private::ConstString, lldb::ModuleSP>
       ExternalTypeModuleMap;
@@ -277,7 +278,7 @@ public:
 
   lldb::user_id_t GetUID(DIERef ref);
 
-  virtual std::unique_ptr<SymbolFileDWARFDwo>
+  std::unique_ptr<SymbolFileDWARFDwo>
   GetDwoSymbolFileForCompileUnit(DWARFUnit &dwarf_cu,
                                  const DWARFDebugInfoEntry &cu_die);
 
@@ -288,11 +289,14 @@ public:
 
   virtual llvm::Optional<uint32_t> GetDwoNum() { return llvm::None; }
 
+  /// If this is a DWARF object with a single CU, return its DW_AT_dwo_id.
+  llvm::Optional<uint64_t> GetDWOId();
+
   static bool
   DIEInDeclContext(const lldb_private::CompilerDeclContext *parent_decl_ctx,
                    const DWARFDIE &die);
 
-  std::vector<lldb_private::CallEdge>
+  std::vector<std::unique_ptr<lldb_private::CallEdge>>
   ParseCallEdgesInFunction(UserID func_id) override;
 
   void Dump(lldb_private::Stream &s) override;
@@ -484,7 +488,6 @@ protected:
   typedef llvm::StringMap<DIERefSet> NameToOffsetMap;
   NameToOffsetMap m_function_scope_qualified_name_map;
   std::unique_ptr<DWARFDebugRanges> m_ranges;
-  std::unique_ptr<DWARFDebugRngLists> m_rnglists;
   UniqueDWARFASTTypeMap m_unique_ast_type_map;
   DIEToTypePtr m_die_to_type;
   DIEToVariableSP m_die_to_variable_sp;
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDebugMap.cpp b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDebugMap.cpp
index a50d4e460bae..cce666a222d0 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDebugMap.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDebugMap.cpp
@@ -39,6 +39,8 @@
 using namespace lldb;
 using namespace lldb_private;
 
+char SymbolFileDWARFDebugMap::ID;
+
 // Subclass lldb_private::Module so we can intercept the
 // "Module::GetObjectFile()" (so we can fixup the object file sections) and
 // also for "Module::GetSymbolFile()" (so we can fixup the symbol file id.
@@ -602,7 +604,7 @@ SymbolFileDWARFDebugMap::CompileUnitInfo *
 SymbolFileDWARFDebugMap::GetCompUnitInfo(const CompileUnit &comp_unit) {
   const uint32_t cu_count = GetNumCompileUnits();
   for (uint32_t i = 0; i < cu_count; ++i) {
-    if (comp_unit == m_compile_unit_infos[i].compile_unit_sp.get())
+    if (&comp_unit == m_compile_unit_infos[i].compile_unit_sp.get())
       return &m_compile_unit_infos[i];
   }
   return nullptr;
@@ -652,12 +654,15 @@ bool SymbolFileDWARFDebugMap::ParseDebugMacros(CompileUnit &comp_unit) {
   return false;
 }
 
-void SymbolFileDWARFDebugMap::ForEachExternalModule(
-    CompileUnit &comp_unit, llvm::function_ref<void(ModuleSP)> f) {
+bool SymbolFileDWARFDebugMap::ForEachExternalModule(
+    CompileUnit &comp_unit,
+    llvm::DenseSet<lldb_private::SymbolFile *> &visited_symbol_files,
+    llvm::function_ref<bool(Module &)> f) {
   std::lock_guard<std::recursive_mutex> guard(GetModuleMutex());
   SymbolFileDWARF *oso_dwarf = GetSymbolFile(comp_unit);
   if (oso_dwarf)
-    oso_dwarf->ForEachExternalModule(comp_unit, f);
+    return oso_dwarf->ForEachExternalModule(comp_unit, visited_symbol_files, f);
+  return false;
 }
 
 bool SymbolFileDWARFDebugMap::ParseSupportFiles(CompileUnit &comp_unit,
@@ -807,12 +812,8 @@ uint32_t SymbolFileDWARFDebugMap::ResolveSymbolContext(
 
     if (!resolve) {
       FileSpec so_file_spec;
-      if (GetFileSpecForSO(i, so_file_spec)) {
-        // Match the full path if the incoming file_spec has a directory (not
-        // just a basename)
-        const bool full_match = (bool)file_spec.GetDirectory();
-        resolve = FileSpec::Equal(file_spec, so_file_spec, full_match);
-      }
+      if (GetFileSpecForSO(i, so_file_spec))
+        resolve = FileSpec::Match(file_spec, so_file_spec);
     }
     if (resolve) {
       SymbolFileDWARF *oso_dwarf = GetSymbolFileByOSOIndex(i);
@@ -1071,7 +1072,7 @@ void SymbolFileDWARFDebugMap::GetTypes(SymbolContextScope *sc_scope,
   }
 }
 
-std::vector<lldb_private::CallEdge>
+std::vector<std::unique_ptr<lldb_private::CallEdge>>
 SymbolFileDWARFDebugMap::ParseCallEdgesInFunction(UserID func_id) {
   uint32_t oso_idx = GetOSOIndexFromUserID(func_id.GetID());
   SymbolFileDWARF *oso_dwarf = GetSymbolFileByOSOIndex(oso_idx);
@@ -1183,6 +1184,16 @@ void SymbolFileDWARFDebugMap::FindTypes(
   });
 }
 
+void SymbolFileDWARFDebugMap::FindTypes(
+    llvm::ArrayRef<CompilerContext> context, LanguageSet languages,
+    llvm::DenseSet<lldb_private::SymbolFile *> &searched_symbol_files,
+    TypeMap &types) {
+  ForEachSymbolFile([&](SymbolFileDWARF *oso_dwarf) -> bool {
+    oso_dwarf->FindTypes(context, languages, searched_symbol_files, types);
+    return false;
+  });
+}
+
 //
 // uint32_t
 // SymbolFileDWARFDebugMap::FindTypes (const SymbolContext& sc, const
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDebugMap.h b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDebugMap.h
index 7adee1b356ce..035a902498be 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDebugMap.h
+++ b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDebugMap.h
@@ -23,7 +23,18 @@ class DWARFDebugAranges;
 class DWARFDeclContext;
 
 class SymbolFileDWARFDebugMap : public lldb_private::SymbolFile {
+  /// LLVM RTTI support.
+  static char ID;
+
 public:
+  /// LLVM RTTI support.
+  /// \{
+  bool isA(const void *ClassID) const override {
+    return ClassID == &ID || SymbolFile::isA(ClassID);
+  }
+  static bool classof(const SymbolFile *obj) { return obj->isA(&ID); }
+  /// \}
+
   // Static Functions
   static void Initialize();
 
@@ -53,9 +64,9 @@ public:
 
   bool ParseDebugMacros(lldb_private::CompileUnit &comp_unit) override;
 
-  void
-  ForEachExternalModule(lldb_private::CompileUnit &comp_unit,
-                        llvm::function_ref<void(lldb::ModuleSP)> f) override;
+  bool ForEachExternalModule(
+      lldb_private::CompileUnit &, llvm::DenseSet<lldb_private::SymbolFile *> &,
+      llvm::function_ref<bool(lldb_private::Module &)>) override;
 
   bool ParseSupportFiles(lldb_private::CompileUnit &comp_unit,
                          lldb_private::FileSpecList &support_files) override;
@@ -114,13 +125,18 @@ public:
             uint32_t max_matches,
             llvm::DenseSet<lldb_private::SymbolFile *> &searched_symbol_files,
             lldb_private::TypeMap &types) override;
+  void
+  FindTypes(llvm::ArrayRef<lldb_private::CompilerContext> context,
+            lldb_private::LanguageSet languages,
+            llvm::DenseSet<lldb_private::SymbolFile *> &searched_symbol_files,
+            lldb_private::TypeMap &types) override;
   lldb_private::CompilerDeclContext FindNamespace(
       lldb_private::ConstString name,
       const lldb_private::CompilerDeclContext *parent_decl_ctx) override;
   void GetTypes(lldb_private::SymbolContextScope *sc_scope,
                 lldb::TypeClass type_mask,
                 lldb_private::TypeList &type_list) override;
-  std::vector<lldb_private::CallEdge>
+  std::vector<std::unique_ptr<lldb_private::CallEdge>>
   ParseCallEdgesInFunction(lldb_private::UserID func_id) override;
 
   void DumpClangAST(lldb_private::Stream &s) override;
@@ -348,8 +364,8 @@ protected:
   /// \param[in] oso_symfile
   ///     The DWARF symbol file that produced the \a line_table
   ///
-  /// \param[in] addr
-  ///     A section offset address from a .o file
+  /// \param[in] line_table
+  ///     A pointer to the line table.
   ///
   /// \return
   ///     Returns a valid line table full of linked addresses, or NULL
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwo.cpp b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwo.cpp
index b0f7e813d4f8..f75f06f31e2d 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwo.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwo.cpp
@@ -21,6 +21,8 @@
 using namespace lldb;
 using namespace lldb_private;
 
+char SymbolFileDWARFDwo::ID;
+
 SymbolFileDWARFDwo::SymbolFileDWARFDwo(ObjectFileSP objfile,
                                        DWARFCompileUnit &dwarf_cu)
     : SymbolFileDWARF(objfile, objfile->GetSectionList(
@@ -135,11 +137,6 @@ SymbolFileDWARF &SymbolFileDWARFDwo::GetBaseSymbolFile() {
   return m_base_dwarf_cu.GetSymbolFileDWARF();
 }
 
-DWARFExpression::LocationListFormat
-SymbolFileDWARFDwo::GetLocationListFormat() const {
-  return DWARFExpression::SplitDwarfLocationList;
-}
-
 llvm::Expected<TypeSystem &>
 SymbolFileDWARFDwo::GetTypeSystemForLanguage(LanguageType language) {
   return GetBaseSymbolFile().GetTypeSystemForLanguage(language);
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwo.h b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwo.h
index ad290cdcf65e..0855dba044e4 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwo.h
+++ b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwo.h
@@ -12,7 +12,18 @@
 #include "SymbolFileDWARF.h"
 
 class SymbolFileDWARFDwo : public SymbolFileDWARF {
+  /// LLVM RTTI support.
+  static char ID;
+
 public:
+  /// LLVM RTTI support.
+  /// \{
+  bool isA(const void *ClassID) const override {
+    return ClassID == &ID || SymbolFileDWARF::isA(ClassID);
+  }
+  static bool classof(const SymbolFile *obj) { return obj->isA(&ID); }
+  /// \}
+
   SymbolFileDWARFDwo(lldb::ObjectFileSP objfile, DWARFCompileUnit &dwarf_cu);
 
   ~SymbolFileDWARFDwo() override = default;
@@ -24,9 +35,6 @@ public:
   DWARFUnit *
   GetDWARFCompileUnit(lldb_private::CompileUnit *comp_unit) override;
 
-  lldb_private::DWARFExpression::LocationListFormat
-  GetLocationListFormat() const override;
-
   size_t GetObjCMethodDIEOffsets(lldb_private::ConstString class_name,
                                  DIEArray &method_die_offsets) override;
 
@@ -36,12 +44,6 @@ public:
   DWARFDIE
   GetDIE(const DIERef &die_ref) override;
 
-  std::unique_ptr<SymbolFileDWARFDwo>
-  GetDwoSymbolFileForCompileUnit(DWARFUnit &dwarf_cu,
-                                 const DWARFDebugInfoEntry &cu_die) override {
-    return nullptr;
-  }
-
   DWARFCompileUnit *GetBaseCompileUnit() override { return &m_base_dwarf_cu; }
 
   llvm::Optional<uint32_t> GetDwoNum() override { return GetID() >> 32; }
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwoDwp.cpp b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwoDwp.cpp
index efea192b17ce..4288dcb5c9bd 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwoDwp.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwoDwp.cpp
@@ -19,6 +19,8 @@
 using namespace lldb;
 using namespace lldb_private;
 
+char SymbolFileDWARFDwoDwp::ID;
+
 SymbolFileDWARFDwoDwp::SymbolFileDWARFDwoDwp(SymbolFileDWARFDwp *dwp_symfile,
                                              ObjectFileSP objfile,
                                              DWARFCompileUnit &dwarf_cu,
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwoDwp.h b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwoDwp.h
index 2105e1a8f6cb..a55795ba5950 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwoDwp.h
+++ b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwoDwp.h
@@ -13,7 +13,17 @@
 #include "SymbolFileDWARFDwp.h"
 
 class SymbolFileDWARFDwoDwp : public SymbolFileDWARFDwo {
+  /// LLVM RTTI support.
+  static char ID;
+
 public:
+  /// LLVM RTTI support.
+  /// \{
+  bool isA(const void *ClassID) const override {
+    return ClassID == &ID || SymbolFileDWARFDwo::isA(ClassID);
+  }
+  static bool classof(const SymbolFile *obj) { return obj->isA(&ID); }
+  /// \}
   SymbolFileDWARFDwoDwp(SymbolFileDWARFDwp *dwp_symfile,
                         lldb::ObjectFileSP objfile, DWARFCompileUnit &dwarf_cu,
                         uint64_t dwo_id);
diff --git a/lldb/source/Plugins/SymbolFile/NativePDB/PdbAstBuilder.cpp b/lldb/source/Plugins/SymbolFile/NativePDB/PdbAstBuilder.cpp
index 986b0b785d87..4588c80aa1b1 100644
--- a/lldb/source/Plugins/SymbolFile/NativePDB/PdbAstBuilder.cpp
+++ b/lldb/source/Plugins/SymbolFile/NativePDB/PdbAstBuilder.cpp
@@ -17,7 +17,7 @@
 #include "Plugins/Language/CPlusPlus/MSVCUndecoratedNameParser.h"
 #include "lldb/Core/Module.h"
 #include "lldb/Symbol/ClangASTContext.h"
-#include "lldb/Symbol/ClangExternalASTSourceCommon.h"
+#include "lldb/Symbol/ClangASTMetadata.h"
 #include "lldb/Symbol/ClangUtil.h"
 #include "lldb/Symbol/ObjectFile.h"
 #include "lldb/Utility/LLDBAssert.h"
@@ -655,7 +655,7 @@ bool PdbAstBuilder::CompleteTagDecl(clang::TagDecl &tag) {
 
   lldbassert(IsTagRecord(type_id, m_index.tpi()));
 
-  clang::QualType tag_qt = m_clang.getASTContext()->getTypeDeclType(&tag);
+  clang::QualType tag_qt = m_clang.getASTContext().getTypeDeclType(&tag);
   ClangASTContext::SetHasExternalStorage(tag_qt.getAsOpaquePtr(), false);
 
   TypeIndex tag_ti = type_id.index;
@@ -700,7 +700,7 @@ clang::QualType PdbAstBuilder::CreateSimpleType(TypeIndex ti) {
 
   if (ti.getSimpleMode() != SimpleTypeMode::Direct) {
     clang::QualType direct_type = GetOrCreateType(ti.makeDirect());
-    return m_clang.getASTContext()->getPointerType(direct_type);
+    return m_clang.getASTContext().getPointerType(direct_type);
   }
 
   if (ti.getSimpleKind() == SimpleTypeKind::NotTranslated)
@@ -725,19 +725,17 @@ clang::QualType PdbAstBuilder::CreatePointerType(const PointerRecord &pointer) {
     MemberPointerInfo mpi = pointer.getMemberInfo();
     clang::QualType class_type = GetOrCreateType(mpi.ContainingType);
 
-    return m_clang.getASTContext()->getMemberPointerType(
+    return m_clang.getASTContext().getMemberPointerType(
         pointee_type, class_type.getTypePtr());
   }
 
   clang::QualType pointer_type;
   if (pointer.getMode() == PointerMode::LValueReference)
-    pointer_type =
-        m_clang.getASTContext()->getLValueReferenceType(pointee_type);
+    pointer_type = m_clang.getASTContext().getLValueReferenceType(pointee_type);
   else if (pointer.getMode() == PointerMode::RValueReference)
-    pointer_type =
-        m_clang.getASTContext()->getRValueReferenceType(pointee_type);
+    pointer_type = m_clang.getASTContext().getRValueReferenceType(pointee_type);
   else
-    pointer_type = m_clang.getASTContext()->getPointerType(pointee_type);
+    pointer_type = m_clang.getASTContext().getPointerType(pointee_type);
 
   if ((pointer.getOptions() & PointerOptions::Const) != PointerOptions::None)
     pointer_type.addConst();
@@ -778,9 +776,8 @@ clang::QualType PdbAstBuilder::CreateRecordType(PdbTypeSymId id,
   metadata.SetUserID(toOpaqueUid(id));
   metadata.SetIsDynamicCXXType(false);
 
-  CompilerType ct =
-      m_clang.CreateRecordType(context, access, uname.c_str(), ttk,
-                               lldb::eLanguageTypeC_plus_plus, &metadata);
+  CompilerType ct = m_clang.CreateRecordType(
+      context, access, uname, ttk, lldb::eLanguageTypeC_plus_plus, &metadata);
 
   lldbassert(ct.IsValid());
 
@@ -1081,7 +1078,7 @@ void PdbAstBuilder::CreateFunctionParameters(PdbCompilandSymId func_id,
     PdbCompilandSymId param_uid(func_id.modi, record_offset);
     clang::QualType qt = GetOrCreateType(param_type);
 
-    CompilerType param_type_ct(&m_clang, qt.getAsOpaquePtr());
+    CompilerType param_type_ct = m_clang.GetType(qt);
     clang::ParmVarDecl *param = m_clang.CreateParameterDeclaration(
         &function_decl, param_name.str().c_str(), param_type_ct,
         clang::SC_None, true);
@@ -1346,7 +1343,7 @@ CompilerType PdbAstBuilder::ToCompilerType(clang::QualType qt) {
 
 CompilerDeclContext
 PdbAstBuilder::ToCompilerDeclContext(clang::DeclContext &context) {
-  return {&m_clang, &context};
+  return m_clang.CreateDeclContext(&context);
 }
 
 clang::Decl * PdbAstBuilder::FromCompilerDecl(CompilerDecl decl) {
diff --git a/lldb/source/Plugins/SymbolFile/NativePDB/SymbolFileNativePDB.cpp b/lldb/source/Plugins/SymbolFile/NativePDB/SymbolFileNativePDB.cpp
index 33b8da3b543b..370c339fb74b 100644
--- a/lldb/source/Plugins/SymbolFile/NativePDB/SymbolFileNativePDB.cpp
+++ b/lldb/source/Plugins/SymbolFile/NativePDB/SymbolFileNativePDB.cpp
@@ -20,7 +20,6 @@
 #include "lldb/Core/StreamBuffer.h"
 #include "lldb/Core/StreamFile.h"
 #include "lldb/Symbol/ClangASTContext.h"
-#include "lldb/Symbol/ClangExternalASTSourceCommon.h"
 #include "lldb/Symbol/ClangUtil.h"
 #include "lldb/Symbol/CompileUnit.h"
 #include "lldb/Symbol/LineTable.h"
@@ -67,6 +66,8 @@ using namespace npdb;
 using namespace llvm::codeview;
 using namespace llvm::pdb;
 
+char SymbolFileNativePDB::ID;
+
 static lldb::LanguageType TranslateLanguage(PDB_Lang lang) {
   switch (lang) {
   case PDB_Lang::Cpp:
@@ -460,7 +461,7 @@ lldb::TypeSP SymbolFileNativePDB::CreateModifierType(PdbTypeSymId type_id,
   return std::make_shared<Type>(toOpaqueUid(type_id), this, ConstString(name),
                                 modified_type->GetByteSize(), nullptr,
                                 LLDB_INVALID_UID, Type::eEncodingIsUID, decl,
-                                ct, Type::eResolveStateFull);
+                                ct, Type::ResolveState::Full);
 }
 
 lldb::TypeSP
@@ -480,7 +481,7 @@ SymbolFileNativePDB::CreatePointerType(PdbTypeSymId type_id,
   return std::make_shared<Type>(toOpaqueUid(type_id), this, ConstString(),
                                 pr.getSize(), nullptr, LLDB_INVALID_UID,
                                 Type::eEncodingIsUID, decl, ct,
-                                Type::eResolveStateFull);
+                                Type::ResolveState::Full);
 }
 
 lldb::TypeSP SymbolFileNativePDB::CreateSimpleType(TypeIndex ti,
@@ -490,7 +491,7 @@ lldb::TypeSP SymbolFileNativePDB::CreateSimpleType(TypeIndex ti,
     Declaration decl;
     return std::make_shared<Type>(
         uid, this, ConstString("std::nullptr_t"), 0, nullptr, LLDB_INVALID_UID,
-        Type::eEncodingIsUID, decl, ct, Type::eResolveStateFull);
+        Type::eEncodingIsUID, decl, ct, Type::ResolveState::Full);
   }
 
   if (ti.getSimpleMode() != SimpleTypeMode::Direct) {
@@ -511,7 +512,7 @@ lldb::TypeSP SymbolFileNativePDB::CreateSimpleType(TypeIndex ti,
     Declaration decl;
     return std::make_shared<Type>(
         uid, this, ConstString(), pointer_size, nullptr, LLDB_INVALID_UID,
-        Type::eEncodingIsUID, decl, ct, Type::eResolveStateFull);
+        Type::eEncodingIsUID, decl, ct, Type::ResolveState::Full);
   }
 
   if (ti.getSimpleKind() == SimpleTypeKind::NotTranslated)
@@ -523,7 +524,7 @@ lldb::TypeSP SymbolFileNativePDB::CreateSimpleType(TypeIndex ti,
   Declaration decl;
   return std::make_shared<Type>(uid, this, ConstString(type_name), size,
                                 nullptr, LLDB_INVALID_UID, Type::eEncodingIsUID,
-                                decl, ct, Type::eResolveStateFull);
+                                decl, ct, Type::ResolveState::Full);
 }
 
 static std::string GetUnqualifiedTypeName(const TagRecord &record) {
@@ -557,7 +558,7 @@ SymbolFileNativePDB::CreateClassStructUnion(PdbTypeSymId type_id,
   return std::make_shared<Type>(toOpaqueUid(type_id), this, ConstString(uname),
                                 size, nullptr, LLDB_INVALID_UID,
                                 Type::eEncodingIsUID, decl, ct,
-                                Type::eResolveStateForward);
+                                Type::ResolveState::Forward);
 }
 
 lldb::TypeSP SymbolFileNativePDB::CreateTagType(PdbTypeSymId type_id,
@@ -584,7 +585,7 @@ lldb::TypeSP SymbolFileNativePDB::CreateTagType(PdbTypeSymId type_id,
       toOpaqueUid(type_id), this, ConstString(uname),
       underlying_type->GetByteSize(), nullptr, LLDB_INVALID_UID,
       lldb_private::Type::eEncodingIsUID, decl, ct,
-      lldb_private::Type::eResolveStateForward);
+      lldb_private::Type::ResolveState::Forward);
 }
 
 TypeSP SymbolFileNativePDB::CreateArrayType(PdbTypeSymId type_id,
@@ -596,7 +597,7 @@ TypeSP SymbolFileNativePDB::CreateArrayType(PdbTypeSymId type_id,
   TypeSP array_sp = std::make_shared<lldb_private::Type>(
       toOpaqueUid(type_id), this, ConstString(), ar.Size, nullptr,
       LLDB_INVALID_UID, lldb_private::Type::eEncodingIsUID, decl, ct,
-      lldb_private::Type::eResolveStateFull);
+      lldb_private::Type::ResolveState::Full);
   array_sp->SetEncodingType(element_type.get());
   return array_sp;
 }
@@ -609,7 +610,7 @@ TypeSP SymbolFileNativePDB::CreateFunctionType(PdbTypeSymId type_id,
   return std::make_shared<lldb_private::Type>(
       toOpaqueUid(type_id), this, ConstString(), 0, nullptr, LLDB_INVALID_UID,
       lldb_private::Type::eEncodingIsUID, decl, ct,
-      lldb_private::Type::eResolveStateFull);
+      lldb_private::Type::ResolveState::Full);
 }
 
 TypeSP SymbolFileNativePDB::CreateProcedureType(PdbTypeSymId type_id,
@@ -619,7 +620,7 @@ TypeSP SymbolFileNativePDB::CreateProcedureType(PdbTypeSymId type_id,
   return std::make_shared<lldb_private::Type>(
       toOpaqueUid(type_id), this, ConstString(), 0, nullptr, LLDB_INVALID_UID,
       lldb_private::Type::eEncodingIsUID, decl, ct,
-      lldb_private::Type::eResolveStateFull);
+      lldb_private::Type::ResolveState::Full);
 }
 
 TypeSP SymbolFileNativePDB::CreateType(PdbTypeSymId type_id, CompilerType ct) {
@@ -1108,9 +1109,7 @@ bool SymbolFileNativePDB::ParseLineTable(CompileUnit &comp_unit) {
       // LLDB wants the index of the file in the list of support files.
       auto fn_iter = llvm::find(cci->m_file_list, *efn);
       lldbassert(fn_iter != cci->m_file_list.end());
-      // LLDB support file indices are 1-based.
-      uint32_t file_index =
-          1 + std::distance(cci->m_file_list.begin(), fn_iter);
+      uint32_t file_index = std::distance(cci->m_file_list.begin(), fn_iter);
 
       std::unique_ptr<LineSequence> sequence(
           line_table->CreateLineSequenceContainer());
@@ -1153,14 +1152,6 @@ bool SymbolFileNativePDB::ParseSupportFiles(CompileUnit &comp_unit,
     FileSpec spec(f, style);
     support_files.Append(spec);
   }
-
-  llvm::SmallString<64> main_source_file =
-      m_index->compilands().GetMainSourceFile(*cci);
-  FileSpec::Style style = main_source_file.startswith("/")
-                              ? FileSpec::Style::posix
-                              : FileSpec::Style::windows;
-  FileSpec spec(main_source_file, style);
-  support_files.Insert(0, spec);
   return true;
 }
 
@@ -1259,8 +1250,9 @@ void SymbolFileNativePDB::FindTypes(
   FindTypesByName(name.GetStringRef(), max_matches, types);
 }
 
-void SymbolFileNativePDB::FindTypes(llvm::ArrayRef<CompilerContext> pattern,
-                                    LanguageSet languages, TypeMap &types) {}
+void SymbolFileNativePDB::FindTypes(
+    llvm::ArrayRef<CompilerContext> pattern, LanguageSet languages,
+    llvm::DenseSet<SymbolFile *> &searched_symbol_files, TypeMap &types) {}
 
 void SymbolFileNativePDB::FindTypesByName(llvm::StringRef name,
                                           uint32_t max_matches,
@@ -1386,7 +1378,7 @@ TypeSP SymbolFileNativePDB::CreateTypedef(PdbGlobalSymId id) {
       toOpaqueUid(id), this, ConstString(udt.Name), target_type->GetByteSize(),
       nullptr, target_type->GetID(), lldb_private::Type::eEncodingIsTypedefUID,
       decl, target_type->GetForwardCompilerType(),
-      lldb_private::Type::eResolveStateForward);
+      lldb_private::Type::ResolveState::Forward);
 }
 
 TypeSP SymbolFileNativePDB::GetOrCreateTypedef(PdbGlobalSymId id) {
diff --git a/lldb/source/Plugins/SymbolFile/NativePDB/SymbolFileNativePDB.h b/lldb/source/Plugins/SymbolFile/NativePDB/SymbolFileNativePDB.h
index ca7de0e7d1ed..a37de0f58ef3 100644
--- a/lldb/source/Plugins/SymbolFile/NativePDB/SymbolFileNativePDB.h
+++ b/lldb/source/Plugins/SymbolFile/NativePDB/SymbolFileNativePDB.h
@@ -41,7 +41,18 @@ class PdbAstBuilder;
 class SymbolFileNativePDB : public SymbolFile {
   friend class UdtRecordCompleter;
 
+  /// LLVM RTTI support.
+  static char ID;
+
 public:
+  /// LLVM RTTI support.
+  /// \{
+  bool isA(const void *ClassID) const override {
+    return ClassID == &ID || SymbolFile::isA(ClassID);
+  }
+  static bool classof(const SymbolFile *obj) { return obj->isA(&ID); }
+  /// \}
+
   // Static Functions
   static void Initialize();
 
@@ -131,6 +142,7 @@ public:
                  TypeMap &types) override;
 
   void FindTypes(llvm::ArrayRef<CompilerContext> pattern, LanguageSet languages,
+                 llvm::DenseSet<SymbolFile *> &searched_symbol_files,
                  TypeMap &types) override;
 
   llvm::Expected<TypeSystem &>
diff --git a/lldb/source/Plugins/SymbolFile/NativePDB/UdtRecordCompleter.cpp b/lldb/source/Plugins/SymbolFile/NativePDB/UdtRecordCompleter.cpp
index 3c494dc83986..7221144407c1 100644
--- a/lldb/source/Plugins/SymbolFile/NativePDB/UdtRecordCompleter.cpp
+++ b/lldb/source/Plugins/SymbolFile/NativePDB/UdtRecordCompleter.cpp
@@ -231,6 +231,6 @@ void UdtRecordCompleter::complete() {
   ClangASTContext::CompleteTagDeclarationDefinition(m_derived_ct);
 
   if (auto *record_decl = llvm::dyn_cast<clang::CXXRecordDecl>(&m_tag_decl)) {
-    m_ast_builder.importer().InsertRecordDecl(record_decl, m_layout);
+    m_ast_builder.importer().SetRecordLayout(record_decl, m_layout);
   }
 }
diff --git a/lldb/source/Plugins/SymbolFile/PDB/PDBASTParser.cpp b/lldb/source/Plugins/SymbolFile/PDB/PDBASTParser.cpp
index 47c4ad088494..6b2dbd9e1e5a 100644
--- a/lldb/source/Plugins/SymbolFile/PDB/PDBASTParser.cpp
+++ b/lldb/source/Plugins/SymbolFile/PDB/PDBASTParser.cpp
@@ -16,7 +16,7 @@
 
 #include "lldb/Core/Module.h"
 #include "lldb/Symbol/ClangASTContext.h"
-#include "lldb/Symbol/ClangExternalASTSourceCommon.h"
+#include "lldb/Symbol/ClangASTMetadata.h"
 #include "lldb/Symbol/ClangUtil.h"
 #include "lldb/Symbol/Declaration.h"
 #include "lldb/Symbol/SymbolFile.h"
@@ -103,9 +103,7 @@ static CompilerType
 GetBuiltinTypeForPDBEncodingAndBitSize(ClangASTContext &clang_ast,
                                        const PDBSymbolTypeBuiltin &pdb_type,
                                        Encoding encoding, uint32_t width) {
-  auto *ast = clang_ast.getASTContext();
-  if (!ast)
-    return CompilerType();
+  clang::ASTContext &ast = clang_ast.getASTContext();
 
   switch (pdb_type.getBuiltinType()) {
   default:
@@ -119,32 +117,25 @@ GetBuiltinTypeForPDBEncodingAndBitSize(ClangASTContext &clang_ast,
   case PDB_BuiltinType::Bool:
     return clang_ast.GetBasicType(eBasicTypeBool);
   case PDB_BuiltinType::Long:
-    if (width == ast->getTypeSize(ast->LongTy))
-      return CompilerType(ClangASTContext::GetASTContext(ast),
-                          ast->LongTy.getAsOpaquePtr());
-    if (width == ast->getTypeSize(ast->LongLongTy))
-      return CompilerType(ClangASTContext::GetASTContext(ast),
-                          ast->LongLongTy.getAsOpaquePtr());
+    if (width == ast.getTypeSize(ast.LongTy))
+      return CompilerType(&clang_ast, ast.LongTy.getAsOpaquePtr());
+    if (width == ast.getTypeSize(ast.LongLongTy))
+      return CompilerType(&clang_ast, ast.LongLongTy.getAsOpaquePtr());
     break;
   case PDB_BuiltinType::ULong:
-    if (width == ast->getTypeSize(ast->UnsignedLongTy))
-      return CompilerType(ClangASTContext::GetASTContext(ast),
-                          ast->UnsignedLongTy.getAsOpaquePtr());
-    if (width == ast->getTypeSize(ast->UnsignedLongLongTy))
-      return CompilerType(ClangASTContext::GetASTContext(ast),
-                          ast->UnsignedLongLongTy.getAsOpaquePtr());
+    if (width == ast.getTypeSize(ast.UnsignedLongTy))
+      return CompilerType(&clang_ast, ast.UnsignedLongTy.getAsOpaquePtr());
+    if (width == ast.getTypeSize(ast.UnsignedLongLongTy))
+      return CompilerType(&clang_ast, ast.UnsignedLongLongTy.getAsOpaquePtr());
     break;
   case PDB_BuiltinType::WCharT:
-    if (width == ast->getTypeSize(ast->WCharTy))
-      return CompilerType(ClangASTContext::GetASTContext(ast),
-                          ast->WCharTy.getAsOpaquePtr());
+    if (width == ast.getTypeSize(ast.WCharTy))
+      return CompilerType(&clang_ast, ast.WCharTy.getAsOpaquePtr());
     break;
   case PDB_BuiltinType::Char16:
-    return CompilerType(ClangASTContext::GetASTContext(ast),
-                        ast->Char16Ty.getAsOpaquePtr());
+    return CompilerType(&clang_ast, ast.Char16Ty.getAsOpaquePtr());
   case PDB_BuiltinType::Char32:
-    return CompilerType(ClangASTContext::GetASTContext(ast),
-                        ast->Char32Ty.getAsOpaquePtr());
+    return CompilerType(&clang_ast, ast.Char32Ty.getAsOpaquePtr());
   case PDB_BuiltinType::Float:
     // Note: types `long double` and `double` have same bit size in MSVC and
     // there is no information in the PDB to distinguish them. So when falling
@@ -405,7 +396,7 @@ lldb::TypeSP PDBASTParser::CreateLLDBTypeFromPDBType(const PDBSymbol &type) {
     // This may occur with const or volatile types. There are separate type
     // symbols in PDB for types with const or volatile modifiers, but we need
     // to create only one declaration for them all.
-    Type::ResolveStateTag type_resolve_state_tag;
+    Type::ResolveState type_resolve_state;
     CompilerType clang_type = m_ast.GetTypeForIdentifier<clang::CXXRecordDecl>(
         ConstString(name), decl_context);
     if (!clang_type.IsValid()) {
@@ -417,9 +408,9 @@ lldb::TypeSP PDBASTParser::CreateLLDBTypeFromPDBType(const PDBSymbol &type) {
       metadata.SetUserID(type.getSymIndexId());
       metadata.SetIsDynamicCXXType(false);
 
-      clang_type = m_ast.CreateRecordType(
-          decl_context, access, name.c_str(), tag_type_kind,
-          lldb::eLanguageTypeC_plus_plus, &metadata);
+      clang_type =
+          m_ast.CreateRecordType(decl_context, access, name, tag_type_kind,
+                                 lldb::eLanguageTypeC_plus_plus, &metadata);
       assert(clang_type.IsValid());
 
       auto record_decl =
@@ -428,7 +419,7 @@ lldb::TypeSP PDBASTParser::CreateLLDBTypeFromPDBType(const PDBSymbol &type) {
       m_uid_to_decl[type.getSymIndexId()] = record_decl;
 
       auto inheritance_attr = clang::MSInheritanceAttr::CreateImplicit(
-          *m_ast.getASTContext(), GetMSInheritance(*udt));
+          m_ast.getASTContext(), GetMSInheritance(*udt));
       record_decl->addAttr(inheritance_attr);
 
       ClangASTContext::StartTagDeclarationDefinition(clang_type);
@@ -442,7 +433,7 @@ lldb::TypeSP PDBASTParser::CreateLLDBTypeFromPDBType(const PDBSymbol &type) {
         ClangASTContext::SetHasExternalStorage(clang_type.GetOpaqueQualType(),
                                                false);
 
-        type_resolve_state_tag = Type::eResolveStateFull;
+        type_resolve_state = Type::ResolveState::Full;
       } else {
         // Add the type to the forward declarations. It will help us to avoid
         // an endless recursion in CompleteTypeFromUdt function.
@@ -451,10 +442,10 @@ lldb::TypeSP PDBASTParser::CreateLLDBTypeFromPDBType(const PDBSymbol &type) {
         ClangASTContext::SetHasExternalStorage(clang_type.GetOpaqueQualType(),
                                                true);
 
-        type_resolve_state_tag = Type::eResolveStateForward;
+        type_resolve_state = Type::ResolveState::Forward;
       }
     } else
-      type_resolve_state_tag = Type::eResolveStateForward;
+      type_resolve_state = Type::ResolveState::Forward;
 
     if (udt->isConstType())
       clang_type = clang_type.AddConstModifier();
@@ -467,7 +458,7 @@ lldb::TypeSP PDBASTParser::CreateLLDBTypeFromPDBType(const PDBSymbol &type) {
         type.getSymIndexId(), m_ast.GetSymbolFile(), ConstString(name),
         udt->getLength(), nullptr, LLDB_INVALID_UID,
         lldb_private::Type::eEncodingIsUID, decl, clang_type,
-        type_resolve_state_tag);
+        type_resolve_state);
   } break;
   case PDB_SymType::Enum: {
     auto enum_type = llvm::dyn_cast<PDBSymbolTypeEnum>(&type);
@@ -535,7 +526,7 @@ lldb::TypeSP PDBASTParser::CreateLLDBTypeFromPDBType(const PDBSymbol &type) {
     return std::make_shared<lldb_private::Type>(
         type.getSymIndexId(), m_ast.GetSymbolFile(), ConstString(name), bytes,
         nullptr, LLDB_INVALID_UID, lldb_private::Type::eEncodingIsUID, decl,
-        ast_enum, lldb_private::Type::eResolveStateFull);
+        ast_enum, lldb_private::Type::ResolveState::Full);
   } break;
   case PDB_SymType::Typedef: {
     auto type_def = llvm::dyn_cast<PDBSymbolTypeTypedef>(&type);
@@ -558,7 +549,7 @@ lldb::TypeSP PDBASTParser::CreateLLDBTypeFromPDBType(const PDBSymbol &type) {
       CompilerType target_ast_type = target_type->GetFullCompilerType();
 
       ast_typedef = m_ast.CreateTypedefType(
-          target_ast_type, name.c_str(), CompilerDeclContext(&m_ast, decl_ctx));
+          target_ast_type, name.c_str(), m_ast.CreateDeclContext(decl_ctx));
       if (!ast_typedef)
         return nullptr;
 
@@ -581,7 +572,7 @@ lldb::TypeSP PDBASTParser::CreateLLDBTypeFromPDBType(const PDBSymbol &type) {
         type_def->getSymIndexId(), m_ast.GetSymbolFile(), ConstString(name),
         size, nullptr, target_type->GetID(),
         lldb_private::Type::eEncodingIsTypedefUID, decl, ast_typedef,
-        lldb_private::Type::eResolveStateFull);
+        lldb_private::Type::ResolveState::Full);
   } break;
   case PDB_SymType::Function:
   case PDB_SymType::FunctionSig: {
@@ -649,7 +640,7 @@ lldb::TypeSP PDBASTParser::CreateLLDBTypeFromPDBType(const PDBSymbol &type) {
         type.getSymIndexId(), m_ast.GetSymbolFile(), ConstString(name),
         llvm::None, nullptr, LLDB_INVALID_UID,
         lldb_private::Type::eEncodingIsUID, decl, func_sig_ast_type,
-        lldb_private::Type::eResolveStateFull);
+        lldb_private::Type::ResolveState::Full);
   } break;
   case PDB_SymType::ArrayType: {
     auto array_type = llvm::dyn_cast<PDBSymbolTypeArray>(&type);
@@ -683,7 +674,7 @@ lldb::TypeSP PDBASTParser::CreateLLDBTypeFromPDBType(const PDBSymbol &type) {
     TypeSP type_sp = std::make_shared<lldb_private::Type>(
         array_type->getSymIndexId(), m_ast.GetSymbolFile(), ConstString(),
         bytes, nullptr, LLDB_INVALID_UID, lldb_private::Type::eEncodingIsUID,
-        decl, array_ast_type, lldb_private::Type::eResolveStateFull);
+        decl, array_ast_type, lldb_private::Type::ResolveState::Full);
     type_sp->SetEncodingType(element_type);
     return type_sp;
   } break;
@@ -712,7 +703,7 @@ lldb::TypeSP PDBASTParser::CreateLLDBTypeFromPDBType(const PDBSymbol &type) {
     return std::make_shared<lldb_private::Type>(
         builtin_type->getSymIndexId(), m_ast.GetSymbolFile(), type_name, bytes,
         nullptr, LLDB_INVALID_UID, lldb_private::Type::eEncodingIsUID, decl,
-        builtin_ast_type, lldb_private::Type::eResolveStateFull);
+        builtin_ast_type, lldb_private::Type::ResolveState::Full);
   } break;
   case PDB_SymType::PointerType: {
     auto *pointer_type = llvm::dyn_cast<PDBSymbolTypePointer>(&type);
@@ -739,7 +730,7 @@ lldb::TypeSP PDBASTParser::CreateLLDBTypeFromPDBType(const PDBSymbol &type) {
           pointer_type->getSymIndexId(), m_ast.GetSymbolFile(), ConstString(),
           pointer_type->getLength(), nullptr, LLDB_INVALID_UID,
           lldb_private::Type::eEncodingIsUID, decl, pointer_ast_type,
-          lldb_private::Type::eResolveStateForward);
+          lldb_private::Type::ResolveState::Forward);
     }
 
     CompilerType pointer_ast_type;
@@ -764,7 +755,7 @@ lldb::TypeSP PDBASTParser::CreateLLDBTypeFromPDBType(const PDBSymbol &type) {
         pointer_type->getSymIndexId(), m_ast.GetSymbolFile(), ConstString(),
         pointer_type->getLength(), nullptr, LLDB_INVALID_UID,
         lldb_private::Type::eEncodingIsUID, decl, pointer_ast_type,
-        lldb_private::Type::eResolveStateFull);
+        lldb_private::Type::ResolveState::Full);
   } break;
   default:
     break;
@@ -900,7 +891,7 @@ PDBASTParser::GetDeclForSymbol(const llvm::pdb::PDBSymbol &symbol) {
 
     // Check if the current context already contains the symbol with the name.
     clang::Decl *decl =
-        GetDeclFromContextByName(*m_ast.getASTContext(), *decl_context, name);
+        GetDeclFromContextByName(m_ast.getASTContext(), *decl_context, name);
     if (!decl) {
       auto type = symbol_file->ResolveTypeUID(data->getTypeId());
       if (!type)
@@ -1160,7 +1151,7 @@ bool PDBASTParser::AddEnumValue(CompilerType enum_type,
   }
   CompilerType underlying_type =
       m_ast.GetEnumerationIntegerType(enum_type.GetOpaqueQualType());
-  uint32_t byte_size = m_ast.getASTContext()->getTypeSize(
+  uint32_t byte_size = m_ast.getASTContext().getTypeSize(
       ClangUtil::GetQualType(underlying_type));
   auto enum_constant_decl = m_ast.AddEnumerationValueToEnumerationType(
       enum_type, decl, name.c_str(), raw_value, byte_size * 8);
@@ -1207,7 +1198,7 @@ bool PDBASTParser::CompleteTypeFromUDT(
   if (!record_decl)
     return static_cast<bool>(compiler_type);
 
-  GetClangASTImporter().InsertRecordDecl(record_decl, layout_info);
+  GetClangASTImporter().SetRecordLayout(record_decl, layout_info);
 
   return static_cast<bool>(compiler_type);
 }
diff --git a/lldb/source/Plugins/SymbolFile/PDB/SymbolFilePDB.cpp b/lldb/source/Plugins/SymbolFile/PDB/SymbolFilePDB.cpp
index 854e735b5f83..917ab68af418 100644
--- a/lldb/source/Plugins/SymbolFile/PDB/SymbolFilePDB.cpp
+++ b/lldb/source/Plugins/SymbolFile/PDB/SymbolFilePDB.cpp
@@ -58,6 +58,8 @@ using namespace lldb;
 using namespace lldb_private;
 using namespace llvm::pdb;
 
+char SymbolFilePDB::ID;
+
 namespace {
 lldb::LanguageType TranslateLanguage(PDB_Lang lang) {
   switch (lang) {
@@ -369,10 +371,6 @@ bool SymbolFilePDB::ParseSupportFiles(
     support_files.AppendIfUnique(spec);
   }
 
-  // LLDB uses the DWARF-like file numeration (one based),
-  // the zeroth file is the compile unit itself
-  support_files.Insert(0, comp_unit);
-
   return true;
 }
 
@@ -668,7 +666,7 @@ SymbolFilePDB::GetDeclContextForUID(lldb::user_id_t uid) {
   if (!decl_context)
     return GetDeclContextContainingUID(uid);
 
-  return CompilerDeclContext(clang_ast_ctx, decl_context);
+  return clang_ast_ctx->CreateDeclContext(decl_context);
 }
 
 lldb_private::CompilerDeclContext
@@ -697,7 +695,7 @@ SymbolFilePDB::GetDeclContextContainingUID(lldb::user_id_t uid) {
   auto decl_context = pdb->GetDeclContextContainingSymbol(*symbol);
   assert(decl_context);
 
-  return CompilerDeclContext(clang_ast_ctx, decl_context);
+  return clang_ast_ctx->CreateDeclContext(decl_context);
 }
 
 void SymbolFilePDB::ParseDeclsForContext(
@@ -1562,9 +1560,10 @@ void SymbolFilePDB::FindTypesByName(
   }
 }
 
-void SymbolFilePDB::FindTypes(llvm::ArrayRef<CompilerContext> pattern,
-                              LanguageSet languages,
-                              lldb_private::TypeMap &types) {}
+void SymbolFilePDB::FindTypes(
+    llvm::ArrayRef<CompilerContext> pattern, LanguageSet languages,
+    llvm::DenseSet<SymbolFile *> &searched_symbol_files,
+    lldb_private::TypeMap &types) {}
 
 void SymbolFilePDB::GetTypesForPDBSymbol(const llvm::pdb::PDBSymbol &pdb_symbol,
                                          uint32_t type_mask,
@@ -1704,8 +1703,7 @@ lldb_private::CompilerDeclContext SymbolFilePDB::FindNamespace(
   if (!namespace_decl)
     return CompilerDeclContext();
 
-  return CompilerDeclContext(clang_type_system,
-                             static_cast<clang::DeclContext *>(namespace_decl));
+  return clang_type_system->CreateDeclContext(namespace_decl);
 }
 
 lldb_private::ConstString SymbolFilePDB::GetPluginName() {
@@ -1777,7 +1775,6 @@ bool SymbolFilePDB::ParseCompileUnitLineTable(CompileUnit &comp_unit,
   auto line_table = std::make_unique<LineTable>(&comp_unit);
 
   // Find contributions to `compiland` from all source and header files.
-  std::string path = comp_unit.GetPath();
   auto files = m_session_up->getSourceFilesForCompiland(*compiland_up);
   if (!files)
     return false;
@@ -1879,9 +1876,7 @@ void SymbolFilePDB::BuildSupportFileIdToSupportFileIndexMap(
   if (!source_files)
     return;
 
-  // LLDB uses the DWARF-like file numeration (one based)
-  int index = 1;
-
+  int index = 0;
   while (auto file = source_files->getNext()) {
     uint32_t source_id = file->getUniqueId();
     index_map[source_id] = index++;
diff --git a/lldb/source/Plugins/SymbolFile/PDB/SymbolFilePDB.h b/lldb/source/Plugins/SymbolFile/PDB/SymbolFilePDB.h
index df717bbbbdb0..7a4eee48771a 100644
--- a/lldb/source/Plugins/SymbolFile/PDB/SymbolFilePDB.h
+++ b/lldb/source/Plugins/SymbolFile/PDB/SymbolFilePDB.h
@@ -22,7 +22,18 @@
 class PDBASTParser;
 
 class SymbolFilePDB : public lldb_private::SymbolFile {
+  /// LLVM RTTI support.
+  static char ID;
+
 public:
+  /// LLVM RTTI support.
+  /// \{
+  bool isA(const void *ClassID) const override {
+    return ClassID == &ID || SymbolFile::isA(ClassID);
+  }
+  static bool classof(const SymbolFile *obj) { return obj->isA(&ID); }
+  /// \}
+
   // Static Functions
   static void Initialize();
 
@@ -134,6 +145,7 @@ public:
 
   void FindTypes(llvm::ArrayRef<lldb_private::CompilerContext> pattern,
                  lldb_private::LanguageSet languages,
+                 llvm::DenseSet<SymbolFile *> &searched_symbol_files,
                  lldb_private::TypeMap &types) override;
 
   void FindTypesByRegex(const lldb_private::RegularExpression &regex,
diff --git a/lldb/source/Plugins/SymbolFile/Symtab/SymbolFileSymtab.cpp b/lldb/source/Plugins/SymbolFile/Symtab/SymbolFileSymtab.cpp
index 62da76581c3e..305efea1afab 100644
--- a/lldb/source/Plugins/SymbolFile/Symtab/SymbolFileSymtab.cpp
+++ b/lldb/source/Plugins/SymbolFile/Symtab/SymbolFileSymtab.cpp
@@ -25,6 +25,8 @@
 using namespace lldb;
 using namespace lldb_private;
 
+char SymbolFileSymtab::ID;
+
 void SymbolFileSymtab::Initialize() {
   PluginManager::RegisterPlugin(GetPluginNameStatic(),
                                 GetPluginDescriptionStatic(), CreateInstance);
diff --git a/lldb/source/Plugins/SymbolFile/Symtab/SymbolFileSymtab.h b/lldb/source/Plugins/SymbolFile/Symtab/SymbolFileSymtab.h
index 2ac4660f0125..1fff8188433e 100644
--- a/lldb/source/Plugins/SymbolFile/Symtab/SymbolFileSymtab.h
+++ b/lldb/source/Plugins/SymbolFile/Symtab/SymbolFileSymtab.h
@@ -16,7 +16,18 @@
 #include "lldb/Symbol/Symtab.h"
 
 class SymbolFileSymtab : public lldb_private::SymbolFile {
+  /// LLVM RTTI support.
+  static char ID;
+
 public:
+  /// LLVM RTTI support.
+  /// \{
+  bool isA(const void *ClassID) const override {
+    return ClassID == &ID || SymbolFile::isA(ClassID);
+  }
+  static bool classof(const SymbolFile *obj) { return obj->isA(&ID); }
+  /// \}
+
   // Constructors and Destructors
   SymbolFileSymtab(lldb::ObjectFileSP objfile_sp);
 
diff --git a/lldb/source/Plugins/SymbolVendor/ELF/SymbolVendorELF.cpp b/lldb/source/Plugins/SymbolVendor/ELF/SymbolVendorELF.cpp
index e61e5763fabb..d4d7a8937c12 100644
--- a/lldb/source/Plugins/SymbolVendor/ELF/SymbolVendorELF.cpp
+++ b/lldb/source/Plugins/SymbolVendor/ELF/SymbolVendorELF.cpp
@@ -119,14 +119,17 @@ SymbolVendorELF::CreateInstance(const lldb::ModuleSP &module_sp,
   SectionList *objfile_section_list = dsym_objfile_sp->GetSectionList();
 
   static const SectionType g_sections[] = {
-      eSectionTypeDWARFDebugAbbrev,   eSectionTypeDWARFDebugAddr,
-      eSectionTypeDWARFDebugAranges,  eSectionTypeDWARFDebugCuIndex,
-      eSectionTypeDWARFDebugFrame,    eSectionTypeDWARFDebugInfo,
-      eSectionTypeDWARFDebugLine,     eSectionTypeDWARFDebugLoc,
-      eSectionTypeDWARFDebugMacInfo,  eSectionTypeDWARFDebugPubNames,
-      eSectionTypeDWARFDebugPubTypes, eSectionTypeDWARFDebugRanges,
-      eSectionTypeDWARFDebugStr,      eSectionTypeDWARFDebugStrOffsets,
-      eSectionTypeELFSymbolTable,     eSectionTypeDWARFGNUDebugAltLink,
+      eSectionTypeDWARFDebugAbbrev,     eSectionTypeDWARFDebugAddr,
+      eSectionTypeDWARFDebugAranges,    eSectionTypeDWARFDebugCuIndex,
+      eSectionTypeDWARFDebugFrame,      eSectionTypeDWARFDebugInfo,
+      eSectionTypeDWARFDebugLine,       eSectionTypeDWARFDebugLineStr,
+      eSectionTypeDWARFDebugLoc,        eSectionTypeDWARFDebugLocLists,
+      eSectionTypeDWARFDebugMacInfo,    eSectionTypeDWARFDebugMacro,
+      eSectionTypeDWARFDebugNames,      eSectionTypeDWARFDebugPubNames,
+      eSectionTypeDWARFDebugPubTypes,   eSectionTypeDWARFDebugRanges,
+      eSectionTypeDWARFDebugRngLists,   eSectionTypeDWARFDebugStr,
+      eSectionTypeDWARFDebugStrOffsets, eSectionTypeDWARFDebugTypes,
+      eSectionTypeELFSymbolTable,       eSectionTypeDWARFGNUDebugAltLink,
   };
   for (SectionType section_type : g_sections) {
     if (SectionSP section_sp =