4 files changed, 211 insertions, 0 deletions
diff --git a/lib/CodeGen/MIRParser/CMakeLists.txt b/lib/CodeGen/MIRParser/CMakeLists.txt
new file mode 100644
index 000000000000..468f072ed7f3
--- /dev/null
+++ b/lib/CodeGen/MIRParser/CMakeLists.txt
@@ -0,0 +1,5 @@
+add_llvm_library(LLVMMIRParser
+  MIRParser.cpp
+  )
+
+add_dependencies(LLVMMIRParser intrinsics_gen)
diff --git a/lib/CodeGen/MIRParser/LLVMBuild.txt b/lib/CodeGen/MIRParser/LLVMBuild.txt
new file mode 100644
index 000000000000..04ae72290f93
--- /dev/null
+++ b/lib/CodeGen/MIRParser/LLVMBuild.txt
@@ -0,0 +1,22 @@
+;===- ./lib/CodeGen/MIRParser/LLVMBuild.txt --------------------*- Conf -*--===;
+;
+;                     The LLVM Compiler Infrastructure
+;
+; This file is distributed under the University of Illinois Open Source
+; License. See LICENSE.TXT for details.
+;
+;===------------------------------------------------------------------------===;
+;
+; This is an LLVMBuild description file for the components in this subdirectory.
+;
+; For more information on the LLVMBuild system, please see:
+;
+;   http://llvm.org/docs/LLVMBuild.html
+;
+;===------------------------------------------------------------------------===;
+
+[component_0]
+type = Library
+name = MIRParser
+parent = CodeGen
+required_libraries = Core Support Target AsmParser CodeGen
diff --git a/lib/CodeGen/MIRParser/MIRParser.cpp b/lib/CodeGen/MIRParser/MIRParser.cpp
new file mode 100644
index 000000000000..7a51b3881afc
--- /dev/null
+++ b/lib/CodeGen/MIRParser/MIRParser.cpp
@@ -0,0 +1,171 @@
+//===- MIRParser.cpp - MIR serialization format parser implementation -----===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the class that parses the optional LLVM IR and machine
+// functions that are stored in MIR files.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/CodeGen/MIRParser/MIRParser.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/AsmParser/Parser.h"
+#include "llvm/CodeGen/MIRYamlMapping.h"
+#include "llvm/IR/Module.h"
+#include "llvm/Support/LineIterator.h"
+#include "llvm/Support/SMLoc.h"
+#include "llvm/Support/SourceMgr.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/YAMLTraits.h"
+#include <memory>
+
+using namespace llvm;
+
+namespace {
+
+/// This class implements the parsing of LLVM IR that's embedded inside a MIR
+/// file.
+class MIRParserImpl {
+  SourceMgr SM;
+  StringRef Filename;
+  LLVMContext &Context;
+
+public:
+  MIRParserImpl(std::unique_ptr<MemoryBuffer> Contents, StringRef Filename,
+                LLVMContext &Context);
+
+  /// Try to parse the optional LLVM module and the machine functions in the MIR
+  /// file.
+  ///
+  /// Return null if an error occurred.
+  std::unique_ptr<Module> parse(SMDiagnostic &Error);
+
+  /// Parse the machine function in the current YAML document.
+  ///
+  /// Return true if an error occurred.
+  bool parseMachineFunction(yaml::Input &In);
+
+private:
+  /// Return a MIR diagnostic converted from an LLVM assembly diagnostic.
+  SMDiagnostic diagFromLLVMAssemblyDiag(const SMDiagnostic &Error,
+                                        SMRange SourceRange);
+};
+
+} // end anonymous namespace
+
+MIRParserImpl::MIRParserImpl(std::unique_ptr<MemoryBuffer> Contents,
+                             StringRef Filename, LLVMContext &Context)
+    : SM(), Filename(Filename), Context(Context) {
+  SM.AddNewSourceBuffer(std::move(Contents), SMLoc());
+}
+
+static void handleYAMLDiag(const SMDiagnostic &Diag, void *Context) {
+  *reinterpret_cast<SMDiagnostic *>(Context) = Diag;
+}
+
+std::unique_ptr<Module> MIRParserImpl::parse(SMDiagnostic &Error) {
+  yaml::Input In(SM.getMemoryBuffer(SM.getMainFileID())->getBuffer(),
+                 /*Ctxt=*/nullptr, handleYAMLDiag, &Error);
+
+  if (!In.setCurrentDocument()) {
+    if (!Error.getMessage().empty())
+      return nullptr;
+    // Create an empty module when the MIR file is empty.
+    return llvm::make_unique<Module>(Filename, Context);
+  }
+
+  std::unique_ptr<Module> M;
+  // Parse the block scalar manually so that we can return unique pointer
+  // without having to go trough YAML traits.
+  if (const auto *BSN =
+          dyn_cast_or_null<yaml::BlockScalarNode>(In.getCurrentNode())) {
+    M = parseAssembly(MemoryBufferRef(BSN->getValue(), Filename), Error,
+                      Context);
+    if (!M) {
+      Error = diagFromLLVMAssemblyDiag(Error, BSN->getSourceRange());
+      return M;
+    }
+    In.nextDocument();
+    if (!In.setCurrentDocument())
+      return M;
+  } else {
+    // Create an new, empty module.
+    M = llvm::make_unique<Module>(Filename, Context);
+  }
+
+  // Parse the machine functions.
+  do {
+    if (parseMachineFunction(In))
+      return nullptr;
+    In.nextDocument();
+  } while (In.setCurrentDocument());
+
+  return M;
+}
+
+bool MIRParserImpl::parseMachineFunction(yaml::Input &In) {
+  yaml::MachineFunction MF;
+  yaml::yamlize(In, MF, false);
+  if (In.error())
+    return true;
+  // TODO: Initialize the real machine function with the state in the yaml
+  // machine function later on.
+  return false;
+}
+
+SMDiagnostic MIRParserImpl::diagFromLLVMAssemblyDiag(const SMDiagnostic &Error,
+                                                     SMRange SourceRange) {
+  assert(SourceRange.isValid());
+
+  // Translate the location of the error from the location in the llvm IR string
+  // to the corresponding location in the MIR file.
+  auto LineAndColumn = SM.getLineAndColumn(SourceRange.Start);
+  unsigned Line = LineAndColumn.first + Error.getLineNo() - 1;
+  unsigned Column = Error.getColumnNo();
+  StringRef LineStr = Error.getLineContents();
+  SMLoc Loc = Error.getLoc();
+
+  // Get the full line and adjust the column number by taking the indentation of
+  // LLVM IR into account.
+  for (line_iterator L(*SM.getMemoryBuffer(SM.getMainFileID()), false), E;
+       L != E; ++L) {
+    if (L.line_number() == Line) {
+      LineStr = *L;
+      Loc = SMLoc::getFromPointer(LineStr.data());
+      auto Indent = LineStr.find(Error.getLineContents());
+      if (Indent != StringRef::npos)
+        Column += Indent;
+      break;
+    }
+  }
+
+  return SMDiagnostic(SM, Loc, Filename, Line, Column, Error.getKind(),
+                      Error.getMessage(), LineStr, Error.getRanges(),
+                      Error.getFixIts());
+}
+
+std::unique_ptr<Module> llvm::parseMIRFile(StringRef Filename,
+                                           SMDiagnostic &Error,
+                                           LLVMContext &Context) {
+  auto FileOrErr = MemoryBuffer::getFile(Filename);
+  if (std::error_code EC = FileOrErr.getError()) {
+    Error = SMDiagnostic(Filename, SourceMgr::DK_Error,
+                         "Could not open input file: " + EC.message());
+    return std::unique_ptr<Module>();
+  }
+  return parseMIR(std::move(FileOrErr.get()), Error, Context);
+}
+
+std::unique_ptr<Module> llvm::parseMIR(std::unique_ptr<MemoryBuffer> Contents,
+                                       SMDiagnostic &Error,
+                                       LLVMContext &Context) {
+  auto Filename = Contents->getBufferIdentifier();
+  MIRParserImpl Parser(std::move(Contents), Filename, Context);
+  return Parser.parse(Error);
+}
diff --git a/lib/CodeGen/MIRParser/Makefile b/lib/CodeGen/MIRParser/Makefile
new file mode 100644
index 000000000000..c02d18806a9c
--- /dev/null
+++ b/lib/CodeGen/MIRParser/Makefile
@@ -0,0 +1,13 @@
+##===- lib/CodeGen/MIRParser/Makefile ----------------------*- Makefile -*-===##
+#
+#                     The LLVM Compiler Infrastructure
+#
+# This file is distributed under the University of Illinois Open Source
+# License. See LICENSE.TXT for details.
+#
+##===----------------------------------------------------------------------===##
+
+LEVEL = ../../..
+LIBRARYNAME = LLVMMIRParser
+
+include $(LEVEL)/Makefile.common