Vendor import of clang trunk r161861:vendor/clang/clang-trunk-r161861

http://llvm.org/svn/llvm-project/cfe/trunk@161861

20 files changed, 331 insertions, 86 deletions

diff --git a/lib/ARCMigrate/ARCMT.cpp b/lib/ARCMigrate/ARCMT.cpp
index 9354dc38b8c6..f291dec21fda 100644
--- a/lib/ARCMigrate/ARCMT.cpp
+++ b/lib/ARCMigrate/ARCMT.cpp
@@ -91,11 +91,40 @@ namespace {
 
 class CaptureDiagnosticConsumer : public DiagnosticConsumer {
   DiagnosticsEngine &Diags;
+  DiagnosticConsumer &DiagClient;
   CapturedDiagList &CapturedDiags;
+  bool HasBegunSourceFile;
 public:
   CaptureDiagnosticConsumer(DiagnosticsEngine &diags,
-                           CapturedDiagList &capturedDiags)
-    : Diags(diags), CapturedDiags(capturedDiags) { }
+                            DiagnosticConsumer &client,
+                            CapturedDiagList &capturedDiags)
+    : Diags(diags), DiagClient(client), CapturedDiags(capturedDiags),
+      HasBegunSourceFile(false) { }
+
+  virtual void BeginSourceFile(const LangOptions &Opts,
+                               const Preprocessor *PP) {
+    // Pass BeginSourceFile message onto DiagClient on first call.
+    // The corresponding EndSourceFile call will be made from an
+    // explicit call to FinishCapture.
+    if (!HasBegunSourceFile) {
+      DiagClient.BeginSourceFile(Opts, PP);
+      HasBegunSourceFile = true;
+    }
+  }
+
+  void FinishCapture() {
+    // Call EndSourceFile on DiagClient on completion of capture to
+    // enable VerifyDiagnosticConsumer to check diagnostics *after*
+    // it has received the diagnostic list.
+    if (HasBegunSourceFile) {
+      DiagClient.EndSourceFile();
+      HasBegunSourceFile = false;
+    }
+  }
+
+  virtual ~CaptureDiagnosticConsumer() {
+    assert(!HasBegunSourceFile && "FinishCapture not called!");
+  }
 
   virtual void HandleDiagnostic(DiagnosticsEngine::Level level,
                                 const Diagnostic &Info) {
@@ -195,8 +224,19 @@ createInvocationForMigration(CompilerInvocation &origCI) {
   CInvok->getLangOpts()->ObjCAutoRefCount = true;
   CInvok->getLangOpts()->setGC(LangOptions::NonGC);
   CInvok->getDiagnosticOpts().ErrorLimit = 0;
-  CInvok->getDiagnosticOpts().Warnings.push_back(
-                                            "error=arc-unsafe-retained-assign");
+  CInvok->getDiagnosticOpts().PedanticErrors = 0;
+
+  // Ignore -Werror flags when migrating.
+  std::vector<std::string> WarnOpts;
+  for (std::vector<std::string>::iterator
+         I = CInvok->getDiagnosticOpts().Warnings.begin(),
+         E = CInvok->getDiagnosticOpts().Warnings.end(); I != E; ++I) {
+    if (!StringRef(*I).startswith("error"))
+      WarnOpts.push_back(*I);
+  }
+  WarnOpts.push_back("error=arc-unsafe-retained-assign");
+  CInvok->getDiagnosticOpts().Warnings = llvm_move(WarnOpts);
+
   CInvok->getLangOpts()->ObjCRuntimeHasWeak = HasARCRuntime(origCI);
 
   return CInvok.take();
@@ -249,13 +289,15 @@ bool arcmt::checkForManualIssues(CompilerInvocation &origCI,
       new DiagnosticsEngine(DiagID, DiagClient, /*ShouldOwnClient=*/false));
 
   // Filter of all diagnostics.
-  CaptureDiagnosticConsumer errRec(*Diags, capturedDiags);
+  CaptureDiagnosticConsumer errRec(*Diags, *DiagClient, capturedDiags);
   Diags->setClient(&errRec, /*ShouldOwnClient=*/false);
 
   OwningPtr<ASTUnit> Unit(
       ASTUnit::LoadFromCompilerInvocationAction(CInvok.take(), Diags));
-  if (!Unit)
+  if (!Unit) {
+    errRec.FinishCapture();
     return true;
+  }
 
   // Don't filter diagnostics anymore.
   Diags->setClient(DiagClient, /*ShouldOwnClient=*/false);
@@ -267,6 +309,7 @@ bool arcmt::checkForManualIssues(CompilerInvocation &origCI,
     DiagClient->BeginSourceFile(Ctx.getLangOpts(), &Unit->getPreprocessor());
     capturedDiags.reportDiagnostics(*Diags);
     DiagClient->EndSourceFile();
+    errRec.FinishCapture();
     return true;
   }
 
@@ -304,6 +347,7 @@ bool arcmt::checkForManualIssues(CompilerInvocation &origCI,
   capturedDiags.reportDiagnostics(*Diags);
 
   DiagClient->EndSourceFile();
+  errRec.FinishCapture();
 
   // If we are migrating code that gets the '-fobjc-arc' flag, make sure
   // to remove it so that we don't get errors from normal compilation.
@@ -480,13 +524,12 @@ public:
 
 class RewritesApplicator : public TransformActions::RewriteReceiver {
   Rewriter &rewriter;
-  ASTContext &Ctx;
   MigrationProcess::RewriteListener *Listener;
 
 public:
   RewritesApplicator(Rewriter &rewriter, ASTContext &ctx,
                      MigrationProcess::RewriteListener *listener)
-    : rewriter(rewriter), Ctx(ctx), Listener(listener) {
+    : rewriter(rewriter), Listener(listener) {
     if (Listener)
       Listener->start(ctx);
   }
@@ -553,7 +596,7 @@ bool MigrationProcess::applyTransform(TransformFn trans,
       new DiagnosticsEngine(DiagID, DiagClient, /*ShouldOwnClient=*/false));
 
   // Filter of all diagnostics.
-  CaptureDiagnosticConsumer errRec(*Diags, capturedDiags);
+  CaptureDiagnosticConsumer errRec(*Diags, *DiagClient, capturedDiags);
   Diags->setClient(&errRec, /*ShouldOwnClient=*/false);
 
   OwningPtr<ARCMTMacroTrackerAction> ASTAction;
@@ -562,8 +605,10 @@ bool MigrationProcess::applyTransform(TransformFn trans,
   OwningPtr<ASTUnit> Unit(
       ASTUnit::LoadFromCompilerInvocationAction(CInvok.take(), Diags,
                                                 ASTAction.get()));
-  if (!Unit)
+  if (!Unit) {
+    errRec.FinishCapture();
     return true;
+  }
   Unit->setOwnsRemappedFileBuffers(false); // FileRemapper manages that.
 
   // Don't filter diagnostics anymore.
@@ -576,6 +621,7 @@ bool MigrationProcess::applyTransform(TransformFn trans,
     DiagClient->BeginSourceFile(Ctx.getLangOpts(), &Unit->getPreprocessor());
     capturedDiags.reportDiagnostics(*Diags);
     DiagClient->EndSourceFile();
+    errRec.FinishCapture();
     return true;
   }
 
@@ -599,6 +645,7 @@ bool MigrationProcess::applyTransform(TransformFn trans,
   }
 
   DiagClient->EndSourceFile();
+  errRec.FinishCapture();
 
   if (DiagClient->getNumErrors())
     return true;
diff --git a/lib/ARCMigrate/CMakeLists.txt b/lib/ARCMigrate/CMakeLists.txt
index fcb7f72ee21d..f602fc8e5f88 100644
--- a/lib/ARCMigrate/CMakeLists.txt
+++ b/lib/ARCMigrate/CMakeLists.txt
@@ -1,5 +1,3 @@
-set(LLVM_USED_LIBS clangBasic clangAST clangParse clangFrontend clangRewrite)
-
 add_clang_library(clangARCMigrate
   ARCMT.cpp
   ARCMTActions.cpp
@@ -25,5 +23,19 @@ add_clang_library(clangARCMigrate
 add_dependencies(clangARCMigrate
   ClangAttrClasses
   ClangAttrList
+  ClangAttrParsedAttrList
+  ClangCommentNodes
   ClangDeclNodes
-  ClangStmtNodes)
+  ClangDiagnosticCommon
+  ClangDiagnosticGroups
+  ClangDiagnosticSema
+  ClangStmtNodes
+  )
+
+target_link_libraries(clangARCMigrate
+  clangBasic
+  clangAST
+  clangParse
+  clangFrontend
+  clangRewrite
+  )
diff --git a/lib/ARCMigrate/FileRemapper.cpp b/lib/ARCMigrate/FileRemapper.cpp
index 474ce7dcbaf8..e9b49b3039ba 100644
--- a/lib/ARCMigrate/FileRemapper.cpp
+++ b/lib/ARCMigrate/FileRemapper.cpp
@@ -77,7 +77,9 @@ bool FileRemapper::initFromFile(StringRef filePath, DiagnosticsEngine &Diag,
   for (unsigned idx = 0; idx+3 <= lines.size(); idx += 3) {
     StringRef fromFilename = lines[idx];
     unsigned long long timeModified;
-    lines[idx+1].getAsInteger(10, timeModified);
+    if (lines[idx+1].getAsInteger(10, timeModified))
+      return report("Invalid file data: '" + lines[idx+1] + "' not a number",
+                    Diag);
     StringRef toFilename = lines[idx+2];
     
     const FileEntry *origFE = FileMgr->getFile(fromFilename);
diff --git a/lib/ARCMigrate/Internals.h b/lib/ARCMigrate/Internals.h
index 59177c483ea0..935fc9b52535 100644
--- a/lib/ARCMigrate/Internals.h
+++ b/lib/ARCMigrate/Internals.h
@@ -12,6 +12,7 @@
 
 #include "clang/ARCMigrate/ARCMT.h"
 #include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/Optional.h"
 
 namespace clang {
   class Sema;
@@ -144,6 +145,7 @@ public:
   Sema &SemaRef;
   TransformActions &TA;
   std::vector<SourceLocation> &ARCMTMacroLocs;
+  llvm::Optional<bool> EnableCFBridgeFns;
 
   MigrationPass(ASTContext &Ctx, LangOptions::GCMode OrigGCMode,
                 Sema &sema, TransformActions &TA,
@@ -157,6 +159,8 @@ public:
   void setNSAllocReallocError(bool val) { MigOptions.NoNSAllocReallocError = val; }
   bool noFinalizeRemoval() const { return MigOptions.NoFinalizeRemoval; }
   void setNoFinalizeRemoval(bool val) {MigOptions.NoFinalizeRemoval = val; }
+
+  bool CFBridgingFunctionsDefined();
 };
 
 static inline StringRef getARCMTMacroName() {
diff --git a/lib/ARCMigrate/ObjCMT.cpp b/lib/ARCMigrate/ObjCMT.cpp
index e63527447633..0098f973e63d 100644
--- a/lib/ARCMigrate/ObjCMT.cpp
+++ b/lib/ARCMigrate/ObjCMT.cpp
@@ -10,6 +10,7 @@
 #include "clang/ARCMigrate/ARCMTActions.h"
 #include "clang/Frontend/CompilerInstance.h"
 #include "clang/Frontend/MultiplexConsumer.h"
+#include "clang/AST/ASTContext.h"
 #include "clang/AST/RecursiveASTVisitor.h"
 #include "clang/AST/NSAPI.h"
 #include "clang/AST/ASTConsumer.h"
@@ -209,6 +210,7 @@ void ObjCMigrateASTConsumer::HandleTranslationUnit(ASTContext &Ctx) {
 }
 
 bool MigrateSourceAction::BeginInvocation(CompilerInstance &CI) {
+  CI.getDiagnostics().setIgnoreAllWarnings(true);
   CI.getPreprocessorOpts().DetailedRecord = true;
   CI.getPreprocessorOpts().DetailedRecordConditionalDirectives = true;
   return true;
diff --git a/lib/ARCMigrate/TransAPIUses.cpp b/lib/ARCMigrate/TransAPIUses.cpp
index aaa82d8dfb7a..5336f859052f 100644
--- a/lib/ARCMigrate/TransAPIUses.cpp
+++ b/lib/ARCMigrate/TransAPIUses.cpp
@@ -19,6 +19,7 @@
 
 #include "Transforms.h"
 #include "Internals.h"
+#include "clang/AST/ASTContext.h"
 #include "clang/Sema/SemaDiagnostic.h"
 
 using namespace clang;
diff --git a/lib/ARCMigrate/TransARCAssign.cpp b/lib/ARCMigrate/TransARCAssign.cpp
index cfa6da1f99f9..b83f85a1fac2 100644
--- a/lib/ARCMigrate/TransARCAssign.cpp
+++ b/lib/ARCMigrate/TransARCAssign.cpp
@@ -23,6 +23,7 @@
 
 #include "Transforms.h"
 #include "Internals.h"
+#include "clang/AST/ASTContext.h"
 #include "clang/Sema/SemaDiagnostic.h"
 
 using namespace clang;
diff --git a/lib/ARCMigrate/TransAutoreleasePool.cpp b/lib/ARCMigrate/TransAutoreleasePool.cpp
index 87877242a124..5205ce4a70a9 100644
--- a/lib/ARCMigrate/TransAutoreleasePool.cpp
+++ b/lib/ARCMigrate/TransAutoreleasePool.cpp
@@ -29,6 +29,7 @@
 
 #include "Transforms.h"
 #include "Internals.h"
+#include "clang/AST/ASTContext.h"
 #include "clang/Sema/SemaDiagnostic.h"
 #include "clang/Basic/SourceManager.h"
 #include <map>
@@ -75,7 +76,7 @@ public:
                                                  &pass.Ctx.Idents.get("drain"));
   }
 
-  void transformBody(Stmt *body) {
+  void transformBody(Stmt *body, Decl *ParentD) {
     Body = body;
     TraverseStmt(body);
   }
diff --git a/lib/ARCMigrate/TransBlockObjCVariable.cpp b/lib/ARCMigrate/TransBlockObjCVariable.cpp
index 3be8132e3b7e..2a79c9aeff20 100644
--- a/lib/ARCMigrate/TransBlockObjCVariable.cpp
+++ b/lib/ARCMigrate/TransBlockObjCVariable.cpp
@@ -9,7 +9,7 @@
 //
 // rewriteBlockObjCVariable:
 //
-// Adding __block to an obj-c variable could be either because the the variable
+// Adding __block to an obj-c variable could be either because the variable
 // is used for output storage or the user wanted to break a retain cycle.
 // This transformation checks whether a reference of the variable for the block
 // is actually needed (it is assigned to or its address is taken) or not.
@@ -27,6 +27,7 @@
 
 #include "Transforms.h"
 #include "Internals.h"
+#include "clang/AST/ASTContext.h"
 #include "clang/Basic/SourceManager.h"
 
 using namespace clang;
@@ -37,7 +38,6 @@ namespace {
 
 class RootBlockObjCVarRewriter :
                           public RecursiveASTVisitor<RootBlockObjCVarRewriter> {
-  MigrationPass &Pass;
   llvm::DenseSet<VarDecl *> &VarsToChange;
 
   class BlockVarChecker : public RecursiveASTVisitor<BlockVarChecker> {
@@ -71,9 +71,8 @@ class RootBlockObjCVarRewriter :
   };
 
 public:
-  RootBlockObjCVarRewriter(MigrationPass &pass,
-                           llvm::DenseSet<VarDecl *> &VarsToChange)
-    : Pass(pass), VarsToChange(VarsToChange) { }
+  RootBlockObjCVarRewriter(llvm::DenseSet<VarDecl *> &VarsToChange)
+    : VarsToChange(VarsToChange) { }
 
   bool VisitBlockDecl(BlockDecl *block) {
     SmallVector<VarDecl *, 4> BlockVars;
@@ -111,16 +110,14 @@ private:
 };
 
 class BlockObjCVarRewriter : public RecursiveASTVisitor<BlockObjCVarRewriter> {
-  MigrationPass &Pass;
   llvm::DenseSet<VarDecl *> &VarsToChange;
 
 public:
-  BlockObjCVarRewriter(MigrationPass &pass,
-                       llvm::DenseSet<VarDecl *> &VarsToChange)
-    : Pass(pass), VarsToChange(VarsToChange) { }
+  BlockObjCVarRewriter(llvm::DenseSet<VarDecl *> &VarsToChange)
+    : VarsToChange(VarsToChange) { }
 
   bool TraverseBlockDecl(BlockDecl *block) {
-    RootBlockObjCVarRewriter(Pass, VarsToChange).TraverseDecl(block);
+    RootBlockObjCVarRewriter(VarsToChange).TraverseDecl(block);
     return true;
   }
 };
@@ -131,7 +128,7 @@ void BlockObjCVariableTraverser::traverseBody(BodyContext &BodyCtx) {
   MigrationPass &Pass = BodyCtx.getMigrationContext().Pass;
   llvm::DenseSet<VarDecl *> VarsToChange;
 
-  BlockObjCVarRewriter trans(Pass, VarsToChange);
+  BlockObjCVarRewriter trans(VarsToChange);
   trans.TraverseStmt(BodyCtx.getTopStmt());
 
   for (llvm::DenseSet<VarDecl *>::iterator
diff --git a/lib/ARCMigrate/TransEmptyStatementsAndDealloc.cpp b/lib/ARCMigrate/TransEmptyStatementsAndDealloc.cpp
index 0fb7141544aa..552cb2fa631c 100644
--- a/lib/ARCMigrate/TransEmptyStatementsAndDealloc.cpp
+++ b/lib/ARCMigrate/TransEmptyStatementsAndDealloc.cpp
@@ -21,6 +21,7 @@
 
 #include "Transforms.h"
 #include "Internals.h"
+#include "clang/AST/ASTContext.h"
 #include "clang/AST/StmtVisitor.h"
 #include "clang/Basic/SourceManager.h"
 
@@ -44,7 +45,7 @@ static bool isEmptyARCMTMacroStatement(NullStmt *S,
   SourceManager &SM = Ctx.getSourceManager();
   std::vector<SourceLocation>::iterator
     I = std::upper_bound(MacroLocs.begin(), MacroLocs.end(), SemiLoc,
-                         SourceManager::LocBeforeThanCompare(SM));
+                         BeforeThanCompare<SourceLocation>(SM));
   --I;
   SourceLocation
       AfterMacroLoc = I->getLocWithOffset(getARCMTMacroName().size());
@@ -210,8 +211,8 @@ static void cleanupDeallocOrFinalize(MigrationPass &pass) {
     ObjCMethodDecl *DeallocM = 0;
     ObjCMethodDecl *FinalizeM = 0;
     for (ObjCImplementationDecl::instmeth_iterator
-           MI = (*I)->instmeth_begin(),
-           ME = (*I)->instmeth_end(); MI != ME; ++MI) {
+           MI = I->instmeth_begin(),
+           ME = I->instmeth_end(); MI != ME; ++MI) {
       ObjCMethodDecl *MD = *MI;
       if (!MD->hasBody())
         continue;
diff --git a/lib/ARCMigrate/TransGCAttrs.cpp b/lib/ARCMigrate/TransGCAttrs.cpp
index 9f6066ef77da..eec7306ba74a 100644
--- a/lib/ARCMigrate/TransGCAttrs.cpp
+++ b/lib/ARCMigrate/TransGCAttrs.cpp
@@ -9,12 +9,13 @@
 
 #include "Transforms.h"
 #include "Internals.h"
-#include "clang/Lex/Lexer.h"
+#include "clang/AST/ASTContext.h"
 #include "clang/Basic/SourceManager.h"
-#include "llvm/Support/SaveAndRestore.h"
+#include "clang/Lex/Lexer.h"
 #include "clang/Sema/SemaDiagnostic.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/TinyPtrVector.h"
+#include "llvm/Support/SaveAndRestore.h"
 
 using namespace clang;
 using namespace arcmt;
@@ -136,7 +137,7 @@ public:
     if (CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(D)) {
       for (CXXRecordDecl::method_iterator
              MI = RD->method_begin(), ME = RD->method_end(); MI != ME; ++MI) {
-        if ((*MI)->isOutOfLine())
+        if (MI->isOutOfLine())
           return true;
       }
       return false;
@@ -166,7 +167,7 @@ public:
 
     for (Decl::redecl_iterator
            I = D->redecls_begin(), E = D->redecls_end(); I != E; ++I)
-      if (!isInMainFile((*I)->getLocation()))
+      if (!isInMainFile(I->getLocation()))
         return false;
     
     return true;
diff --git a/lib/ARCMigrate/TransGCCalls.cpp b/lib/ARCMigrate/TransGCCalls.cpp
index 1be902088c62..2ec480c0af64 100644
--- a/lib/ARCMigrate/TransGCCalls.cpp
+++ b/lib/ARCMigrate/TransGCCalls.cpp
@@ -9,6 +9,7 @@
 
 #include "Transforms.h"
 #include "Internals.h"
+#include "clang/AST/ASTContext.h"
 #include "clang/Sema/SemaDiagnostic.h"
 
 using namespace clang;
@@ -20,13 +21,12 @@ namespace {
 class GCCollectableCallsChecker :
                          public RecursiveASTVisitor<GCCollectableCallsChecker> {
   MigrationContext &MigrateCtx;
-  ParentMap &PMap;
   IdentifierInfo *NSMakeCollectableII;
   IdentifierInfo *CFMakeCollectableII;
 
 public:
-  GCCollectableCallsChecker(MigrationContext &ctx, ParentMap &map)
-    : MigrateCtx(ctx), PMap(map) {
+  GCCollectableCallsChecker(MigrationContext &ctx)
+    : MigrateCtx(ctx) {
     IdentifierTable &Ids = MigrateCtx.Pass.Ctx.Idents;
     NSMakeCollectableII = &Ids.get("NSMakeCollectable");
     CFMakeCollectableII = &Ids.get("CFMakeCollectable");
@@ -78,7 +78,6 @@ public:
 } // anonymous namespace
 
 void GCCollectableCallsTraverser::traverseBody(BodyContext &BodyCtx) {
-  GCCollectableCallsChecker(BodyCtx.getMigrationContext(),
-                            BodyCtx.getParentMap())
+  GCCollectableCallsChecker(BodyCtx.getMigrationContext())
                                             .TraverseStmt(BodyCtx.getTopStmt());
 }
diff --git a/lib/ARCMigrate/TransProperties.cpp b/lib/ARCMigrate/TransProperties.cpp
index cc85fe25cca9..fdd6e8863b59 100644
--- a/lib/ARCMigrate/TransProperties.cpp
+++ b/lib/ARCMigrate/TransProperties.cpp
@@ -309,17 +309,8 @@ private:
         if (RE->getDecl() != Ivar)
           return true;
 
-      if (ObjCMessageExpr *
-            ME = dyn_cast<ObjCMessageExpr>(E->getRHS()->IgnoreParenCasts()))
-        if (ME->getMethodFamily() == OMF_retain)
+        if (isPlusOneAssign(E))
           return false;
-
-      ImplicitCastExpr *implCE = dyn_cast<ImplicitCastExpr>(E->getRHS());
-      while (implCE && implCE->getCastKind() ==  CK_BitCast)
-        implCE = dyn_cast<ImplicitCastExpr>(implCE->getSubExpr());
-
-      if (implCE && implCE->getCastKind() == CK_ARCConsumeObject)
-        return false;
       }
 
       return true;
diff --git a/lib/ARCMigrate/TransRetainReleaseDealloc.cpp b/lib/ARCMigrate/TransRetainReleaseDealloc.cpp
index 11a655334144..91d2b399e3f1 100644
--- a/lib/ARCMigrate/TransRetainReleaseDealloc.cpp
+++ b/lib/ARCMigrate/TransRetainReleaseDealloc.cpp
@@ -19,10 +19,11 @@
 
 #include "Transforms.h"
 #include "Internals.h"
-#include "clang/Sema/SemaDiagnostic.h"
+#include "clang/AST/ASTContext.h"
 #include "clang/AST/ParentMap.h"
-#include "clang/Lex/Lexer.h"
 #include "clang/Basic/SourceManager.h"
+#include "clang/Lex/Lexer.h"
+#include "clang/Sema/SemaDiagnostic.h"
 
 using namespace clang;
 using namespace arcmt;
@@ -49,7 +50,7 @@ public:
         Pass.Ctx.Selectors.getNullarySelector(&Pass.Ctx.Idents.get("finalize"));
   }
 
-  void transformBody(Stmt *body) {
+  void transformBody(Stmt *body, Decl *ParentD) {
     Body = body;
     collectRemovables(body, Removables);
     StmtMap.reset(new ParentMap(body));
@@ -64,14 +65,16 @@ public:
       return true;
     case OMF_autorelease:
       if (isRemovable(E)) {
-        // An unused autorelease is badness. If we remove it the receiver
-        // will likely die immediately while previously it was kept alive
-        // by the autorelease pool. This is bad practice in general, leave it
-        // and emit an error to force the user to restructure his code.
-        Pass.TA.reportError("it is not safe to remove an unused 'autorelease' "
-            "message; its receiver may be destroyed immediately",
-            E->getLocStart(), E->getSourceRange());
-        return true;
+        if (!isCommonUnusedAutorelease(E)) {
+          // An unused autorelease is badness. If we remove it the receiver
+          // will likely die immediately while previously it was kept alive
+          // by the autorelease pool. This is bad practice in general, leave it
+          // and emit an error to force the user to restructure his code.
+          Pass.TA.reportError("it is not safe to remove an unused 'autorelease' "
+              "message; its receiver may be destroyed immediately",
+              E->getLocStart(), E->getSourceRange());
+          return true;
+        }
       }
       // Pass through.
     case OMF_retain:
@@ -156,6 +159,80 @@ public:
   }
 
 private:
+  /// \brief Checks for idioms where an unused -autorelease is common.
+  ///
+  /// Currently only returns true for this idiom which is common in property
+  /// setters:
+  ///
+  ///   [backingValue autorelease];
+  ///   backingValue = [newValue retain]; // in general a +1 assign
+  ///
+  bool isCommonUnusedAutorelease(ObjCMessageExpr *E) {
+    Expr *Rec = E->getInstanceReceiver();
+    if (!Rec)
+      return false;
+
+    Decl *RefD = getReferencedDecl(Rec);
+    if (!RefD)
+      return false;
+
+    Stmt *OuterS = E, *InnerS;
+    do {
+      InnerS = OuterS;
+      OuterS = StmtMap->getParent(InnerS);
+    }
+    while (OuterS && (isa<ParenExpr>(OuterS) ||
+                      isa<CastExpr>(OuterS) ||
+                      isa<ExprWithCleanups>(OuterS)));
+    
+    if (!OuterS)
+      return false;
+
+    // Find next statement after the -autorelease.
+
+    Stmt::child_iterator currChildS = OuterS->child_begin();
+    Stmt::child_iterator childE = OuterS->child_end();
+    for (; currChildS != childE; ++currChildS) {
+      if (*currChildS == InnerS)
+        break;
+    }
+    if (currChildS == childE)
+      return false;
+    ++currChildS;
+    if (currChildS == childE)
+      return false;
+
+    Stmt *nextStmt = *currChildS;
+    if (!nextStmt)
+      return false;
+    nextStmt = nextStmt->IgnoreImplicit();
+
+    // Check for "RefD = [+1 retained object];".
+    
+    if (BinaryOperator *Bop = dyn_cast<BinaryOperator>(nextStmt)) {
+      if (RefD != getReferencedDecl(Bop->getLHS()))
+        return false;
+      if (isPlusOneAssign(Bop))
+        return true;
+    }
+    return false;
+  }
+
+  Decl *getReferencedDecl(Expr *E) {
+    if (!E)
+      return 0;
+
+    E = E->IgnoreParenCasts();
+    if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))
+      return DRE->getDecl();
+    if (MemberExpr *ME = dyn_cast<MemberExpr>(E))
+      return ME->getMemberDecl();
+    if (ObjCIvarRefExpr *IRE = dyn_cast<ObjCIvarRefExpr>(E))
+      return IRE->getDecl();
+
+    return 0;
+  }
+
   /// \brief Check if the retain/release is due to a GCD/XPC macro that are
   /// defined as:
   ///
diff --git a/lib/ARCMigrate/TransUnbridgedCasts.cpp b/lib/ARCMigrate/TransUnbridgedCasts.cpp
index 48437c795fa9..ac18b5d6e739 100644
--- a/lib/ARCMigrate/TransUnbridgedCasts.cpp
+++ b/lib/ARCMigrate/TransUnbridgedCasts.cpp
@@ -12,7 +12,7 @@
 // A cast of non-objc pointer to an objc one is checked. If the non-objc pointer
 // is from a file-level variable, __bridge cast is used to convert it.
 // For the result of a function call that we know is +1/+0,
-// __bridge/__bridge_transfer is used.
+// __bridge/CFBridgingRelease is used.
 //
 //  NSString *str = (NSString *)kUTTypePlainText;
 //  str = b ? kUTTypeRTF : kUTTypePlainText;
@@ -21,8 +21,8 @@
 // ---->
 //  NSString *str = (__bridge NSString *)kUTTypePlainText;
 //  str = (__bridge NSString *)(b ? kUTTypeRTF : kUTTypePlainText);
-// NSString *_uuidString = (__bridge_transfer NSString *)
-//                               CFUUIDCreateString(kCFAllocatorDefault, _uuid);
+// NSString *_uuidString = (NSString *)
+//            CFBridgingRelease(CFUUIDCreateString(kCFAllocatorDefault, _uuid));
 //
 // For a C pointer to ObjC, for casting 'self', __bridge is used.
 //
@@ -35,9 +35,11 @@
 #include "Transforms.h"
 #include "Internals.h"
 #include "clang/Analysis/DomainSpecific/CocoaConventions.h"
-#include "clang/Sema/SemaDiagnostic.h"
+#include "clang/AST/ASTContext.h"
 #include "clang/AST/ParentMap.h"
 #include "clang/Basic/SourceManager.h"
+#include "clang/Lex/Lexer.h"
+#include "clang/Sema/SemaDiagnostic.h"
 #include "llvm/ADT/SmallString.h"
 
 using namespace clang;
@@ -50,13 +52,15 @@ class UnbridgedCastRewriter : public RecursiveASTVisitor<UnbridgedCastRewriter>{
   MigrationPass &Pass;
   IdentifierInfo *SelfII;
   OwningPtr<ParentMap> StmtMap;
+  Decl *ParentD;
 
 public:
-  UnbridgedCastRewriter(MigrationPass &pass) : Pass(pass) {
+  UnbridgedCastRewriter(MigrationPass &pass) : Pass(pass), ParentD(0) {
     SelfII = &Pass.Ctx.Idents.get("self");
   }
 
-  void transformBody(Stmt *body) {
+  void transformBody(Stmt *body, Decl *ParentD) {
+    this->ParentD = ParentD;
     StmtMap.reset(new ParentMap(body));
     TraverseStmt(body);
   }
@@ -155,6 +159,21 @@ private:
         }
       }
     }
+
+    // If returning an ivar or a member of an ivar from a +0 method, use
+    // a __bridge cast.
+    Expr *base = inner->IgnoreParenImpCasts();
+    while (isa<MemberExpr>(base))
+      base = cast<MemberExpr>(base)->getBase()->IgnoreParenImpCasts();
+    if (isa<ObjCIvarRefExpr>(base) &&
+        isa<ReturnStmt>(StmtMap->getParentIgnoreParenCasts(E))) {
+      if (ObjCMethodDecl *method = dyn_cast_or_null<ObjCMethodDecl>(ParentD)) {
+        if (!method->hasAttr<NSReturnsRetainedAttr>()) {
+          castToObjCObject(E, /*retained=*/false);
+          return;
+        }
+      }
+    }
   }
 
   void castToObjCObject(CastExpr *E, bool retained) {
@@ -191,22 +210,48 @@ private:
     TA.clearDiagnostic(diag::err_arc_mismatched_cast,
                        diag::err_arc_cast_requires_bridge,
                        E->getLocStart());
-    if (CStyleCastExpr *CCE = dyn_cast<CStyleCastExpr>(E)) {
-      TA.insertAfterToken(CCE->getLParenLoc(), bridge);
-    } else {
-      SourceLocation insertLoc = E->getSubExpr()->getLocStart();
-      SmallString<128> newCast;
-      newCast += '(';
-      newCast += bridge;
-      newCast += E->getType().getAsString(Pass.Ctx.getPrintingPolicy());
-      newCast += ')';
-
-      if (isa<ParenExpr>(E->getSubExpr())) {
-        TA.insert(insertLoc, newCast.str());
+    if (Kind == OBC_Bridge || !Pass.CFBridgingFunctionsDefined()) {
+      if (CStyleCastExpr *CCE = dyn_cast<CStyleCastExpr>(E)) {
+        TA.insertAfterToken(CCE->getLParenLoc(), bridge);
       } else {
+        SourceLocation insertLoc = E->getSubExpr()->getLocStart();
+        SmallString<128> newCast;
         newCast += '(';
-        TA.insert(insertLoc, newCast.str());
-        TA.insertAfterToken(E->getLocEnd(), ")");
+        newCast += bridge;
+        newCast += E->getType().getAsString(Pass.Ctx.getPrintingPolicy());
+        newCast += ')';
+
+        if (isa<ParenExpr>(E->getSubExpr())) {
+          TA.insert(insertLoc, newCast.str());
+        } else {
+          newCast += '(';
+          TA.insert(insertLoc, newCast.str());
+          TA.insertAfterToken(E->getLocEnd(), ")");
+        }
+      }
+    } else {
+      assert(Kind == OBC_BridgeTransfer || Kind == OBC_BridgeRetained);
+      SmallString<32> BridgeCall;
+
+      Expr *WrapE = E->getSubExpr();
+      SourceLocation InsertLoc = WrapE->getLocStart();
+
+      SourceManager &SM = Pass.Ctx.getSourceManager();
+      char PrevChar = *SM.getCharacterData(InsertLoc.getLocWithOffset(-1));
+      if (Lexer::isIdentifierBodyChar(PrevChar, Pass.Ctx.getLangOpts()))
+        BridgeCall += ' ';
+
+      if (Kind == OBC_BridgeTransfer)
+        BridgeCall += "CFBridgingRelease";
+      else
+        BridgeCall += "CFBridgingRetain";
+
+      if (isa<ParenExpr>(WrapE)) {
+        TA.insert(InsertLoc, BridgeCall);
+      } else {
+        BridgeCall += '(';
+        TA.insert(InsertLoc, BridgeCall);
+        TA.insertAfterToken(WrapE->getLocEnd(), ")");
       }
     }
   }
diff --git a/lib/ARCMigrate/TransUnusedInitDelegate.cpp b/lib/ARCMigrate/TransUnusedInitDelegate.cpp
index 60ed32aef4ce..3057e391d0a8 100644
--- a/lib/ARCMigrate/TransUnusedInitDelegate.cpp
+++ b/lib/ARCMigrate/TransUnusedInitDelegate.cpp
@@ -22,6 +22,7 @@
 
 #include "Transforms.h"
 #include "Internals.h"
+#include "clang/AST/ASTContext.h"
 #include "clang/Sema/SemaDiagnostic.h"
 
 using namespace clang;
@@ -40,7 +41,7 @@ public:
   UnusedInitRewriter(MigrationPass &pass)
     : Body(0), Pass(pass) { }
 
-  void transformBody(Stmt *body) {
+  void transformBody(Stmt *body, Decl *ParentD) {
     Body = body;
     collectRemovables(body, Removables);
     TraverseStmt(body);
diff --git a/lib/ARCMigrate/TransZeroOutPropsInDealloc.cpp b/lib/ARCMigrate/TransZeroOutPropsInDealloc.cpp
index d1f08aac28c2..a07596d0cb0c 100644
--- a/lib/ARCMigrate/TransZeroOutPropsInDealloc.cpp
+++ b/lib/ARCMigrate/TransZeroOutPropsInDealloc.cpp
@@ -15,6 +15,7 @@
 
 #include "Transforms.h"
 #include "Internals.h"
+#include "clang/AST/ASTContext.h"
 
 using namespace clang;
 using namespace arcmt;
diff --git a/lib/ARCMigrate/TransformActions.cpp b/lib/ARCMigrate/TransformActions.cpp
index 0ecfeb54f85d..783db1c8f3aa 100644
--- a/lib/ARCMigrate/TransformActions.cpp
+++ b/lib/ARCMigrate/TransformActions.cpp
@@ -8,6 +8,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "Internals.h"
+#include "clang/AST/ASTContext.h"
 #include "clang/AST/Expr.h"
 #include "clang/Lex/Preprocessor.h"
 #include "clang/Basic/SourceManager.h"
diff --git a/lib/ARCMigrate/Transforms.cpp b/lib/ARCMigrate/Transforms.cpp
index d342d1aa0477..1175c363163b 100644
--- a/lib/ARCMigrate/Transforms.cpp
+++ b/lib/ARCMigrate/Transforms.cpp
@@ -9,11 +9,14 @@
 
 #include "Transforms.h"
 #include "Internals.h"
-#include "clang/Sema/SemaDiagnostic.h"
+#include "clang/Analysis/DomainSpecific/CocoaConventions.h"
+#include "clang/AST/ASTContext.h"
 #include "clang/AST/RecursiveASTVisitor.h"
 #include "clang/AST/StmtVisitor.h"
-#include "clang/Lex/Lexer.h"
 #include "clang/Basic/SourceManager.h"
+#include "clang/Lex/Lexer.h"
+#include "clang/Sema/Sema.h"
+#include "clang/Sema/SemaDiagnostic.h"
 #include "llvm/ADT/StringSwitch.h"
 #include "llvm/ADT/DenseSet.h"
 #include <map>
@@ -24,6 +27,13 @@ using namespace trans;
 
 ASTTraverser::~ASTTraverser() { }
 
+bool MigrationPass::CFBridgingFunctionsDefined() {
+  if (!EnableCFBridgeFns.hasValue())
+    EnableCFBridgeFns = SemaRef.isKnownName("CFBridgingRetain") &&
+                        SemaRef.isKnownName("CFBridgingRelease");
+  return *EnableCFBridgeFns;
+}
+
 //===----------------------------------------------------------------------===//
 // Helpers.
 //===----------------------------------------------------------------------===//
@@ -56,6 +66,47 @@ bool trans::canApplyWeak(ASTContext &Ctx, QualType type,
   return true;
 }
 
+bool trans::isPlusOneAssign(const BinaryOperator *E) {
+  if (E->getOpcode() != BO_Assign)
+    return false;
+
+  if (const ObjCMessageExpr *
+        ME = dyn_cast<ObjCMessageExpr>(E->getRHS()->IgnoreParenCasts()))
+    if (ME->getMethodFamily() == OMF_retain)
+      return true;
+
+  if (const CallExpr *
+        callE = dyn_cast<CallExpr>(E->getRHS()->IgnoreParenCasts())) {
+    if (const FunctionDecl *FD = callE->getDirectCallee()) {
+      if (FD->getAttr<CFReturnsRetainedAttr>())
+        return true;
+
+      if (FD->isGlobal() &&
+          FD->getIdentifier() &&
+          FD->getParent()->isTranslationUnit() &&
+          FD->getLinkage() == ExternalLinkage &&
+          ento::cocoa::isRefType(callE->getType(), "CF",
+                                 FD->getIdentifier()->getName())) {
+        StringRef fname = FD->getIdentifier()->getName();
+        if (fname.endswith("Retain") ||
+            fname.find("Create") != StringRef::npos ||
+            fname.find("Copy") != StringRef::npos) {
+          return true;
+        }
+      }
+    }
+  }
+
+  const ImplicitCastExpr *implCE = dyn_cast<ImplicitCastExpr>(E->getRHS());
+  while (implCE && implCE->getCastKind() ==  CK_BitCast)
+    implCE = dyn_cast<ImplicitCastExpr>(implCE->getSubExpr());
+
+  if (implCE && implCE->getCastKind() == CK_ARCConsumeObject)
+    return true;
+
+  return false;
+}
+
 /// \brief 'Loc' is the end of a statement range. This returns the location
 /// immediately after the semicolon following the statement.
 /// If no semicolon is found or the location is inside a macro, the returned
@@ -472,8 +523,8 @@ static void GCRewriteFinalize(MigrationPass &pass) {
   for (impl_iterator I = impl_iterator(DC->decls_begin()),
        E = impl_iterator(DC->decls_end()); I != E; ++I) {
     for (ObjCImplementationDecl::instmeth_iterator
-         MI = (*I)->instmeth_begin(),
-         ME = (*I)->instmeth_end(); MI != ME; ++MI) {
+         MI = I->instmeth_begin(),
+         ME = I->instmeth_end(); MI != ME; ++MI) {
       ObjCMethodDecl *MD = *MI;
       if (!MD->hasBody())
         continue;
diff --git a/lib/ARCMigrate/Transforms.h b/lib/ARCMigrate/Transforms.h
index 445c3e599d65..5d4ac9446045 100644
--- a/lib/ARCMigrate/Transforms.h
+++ b/lib/ARCMigrate/Transforms.h
@@ -13,6 +13,7 @@
 #include "clang/AST/RecursiveASTVisitor.h"
 #include "clang/AST/ParentMap.h"
 #include "llvm/ADT/DenseSet.h"
+#include "llvm/Support/SaveAndRestore.h"
 
 namespace clang {
   class Decl;
@@ -154,6 +155,8 @@ public:
 bool canApplyWeak(ASTContext &Ctx, QualType type,
                   bool AllowOnUnknownClass = false);
 
+bool isPlusOneAssign(const BinaryOperator *E);
+
 /// \brief 'Loc' is the end of a statement range. This returns the location
 /// immediately after the semicolon following the statement.
 /// If no semicolon is found or the location is inside a macro, the returned
@@ -174,15 +177,22 @@ StringRef getNilString(ASTContext &Ctx);
 template <typename BODY_TRANS>
 class BodyTransform : public RecursiveASTVisitor<BodyTransform<BODY_TRANS> > {
   MigrationPass &Pass;
+  Decl *ParentD;
 
+  typedef RecursiveASTVisitor<BodyTransform<BODY_TRANS> > base;
 public:
-  BodyTransform(MigrationPass &pass) : Pass(pass) { }
+  BodyTransform(MigrationPass &pass) : Pass(pass), ParentD(0) { }
 
   bool TraverseStmt(Stmt *rootS) {
     if (rootS)
-      BODY_TRANS(Pass).transformBody(rootS);
+      BODY_TRANS(Pass).transformBody(rootS, ParentD);
     return true;
   }
+
+  bool TraverseObjCMethodDecl(ObjCMethodDecl *D) {
+    SaveAndRestore<Decl *> SetParent(ParentD, D);
+    return base::TraverseObjCMethodDecl(D);
+  }
 };
 
 typedef llvm::DenseSet<Expr *> ExprSet;