3 files changed, 22 insertions, 0 deletions
diff --git a/clang/lib/CodeGen/CGObjCGNU.cpp b/clang/lib/CodeGen/CGObjCGNU.cpp
index db0bd951c1e..6cf370f79ea 100644
--- a/clang/lib/CodeGen/CGObjCGNU.cpp
+++ b/clang/lib/CodeGen/CGObjCGNU.cpp
@@ -322,6 +322,11 @@ private:
   /// Function used for non-object declared property setters.
   LazyRuntimeFunction SetStructPropertyFn;
 
+  /// Function called before message sends, when tracing
+  LazyRuntimeFunction TraceEnterFn;
+  /// Function called after  message sends, when tracing
+  LazyRuntimeFunction TraceExitFn;
+
   /// The version of the runtime that this class targets.  Must match the
   /// version in the runtime.
   int RuntimeVersion;
@@ -768,6 +773,9 @@ CGObjCGNU::CGObjCGNU(CodeGenModule &cgm, unsigned runtimeABIVersion,
   SetStructPropertyFn.init(&CGM, "objc_setPropertyStruct", VoidTy, PtrTy, PtrTy, 
       PtrDiffTy, BoolTy, BoolTy, NULL);
 
+  TraceEnterFn.init(&CGM, "objc_trace_enter", VoidTy, IdTy, SelectorTy, NULL);
+  TraceExitFn.init(&CGM, "objc_trace_exit", VoidTy, IdTy, SelectorTy, NULL);
+
   // IMP type
   llvm::Type *IMPArgs[] = { IdTy, SelectorTy };
   IMPTy = llvm::PointerType::getUnqual(llvm::FunctionType::get(IdTy, IMPArgs,
@@ -1212,12 +1220,19 @@ CGObjCGNU::GenerateMessageSend(CodeGenFunction &CGF,
   ActualArgs[0] = CallArg(RValue::get(Receiver), ASTIdTy, false);
 
   imp = EnforceType(Builder, imp, MSI.MessengerType);
+  if (CGM.getCodeGenOpts().ObjCTrace) {
+    Builder.CreateCall2(TraceEnterFn, Receiver, cmd);
+  }
 
   llvm::Instruction *call;
   RValue msgRet = CGF.EmitCall(MSI.CallInfo, imp, Return, ActualArgs,
       0, &call);
   call->setMetadata(msgSendMDKind, node);
 
+  if (CGM.getCodeGenOpts().ObjCTrace) {
+    Builder.CreateCall2(TraceExitFn, Receiver, cmd);
+  }
+
 
   if (!isPointerSizedReturn) {
     messageBB = CGF.Builder.GetInsertBlock();
diff --git a/clang/lib/Driver/Tools.cpp b/clang/lib/Driver/Tools.cpp
index 8093d2f6dfd..3bb68185448 100644
--- a/clang/lib/Driver/Tools.cpp
+++ b/clang/lib/Driver/Tools.cpp
@@ -2400,6 +2400,10 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
     CmdArgs.push_back("-fobjc-default-synthesize-properties");
   }
 
+  if (Args.hasFlag(options::OPT_fobjc_trace, options::OPT_fno_objc_trace,
+                   false))
+    CmdArgs.push_back("-fobjc-trace");
+
   // Allow -fno-objc-arr to trump -fobjc-arr/-fobjc-arc.
   // NOTE: This logic is duplicated in ToolChains.cpp.
   bool ARC = isObjCAutoRefCount(Args);
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 02947c778c3..aae0b48e75e 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -249,6 +249,8 @@ static void CodeGenOptsToArgs(const CodeGenOptions &Opts, ToArgsList &Res) {
     Res.push_back("-mconstructor-aliases");
   if (Opts.ObjCAutoRefCountExceptions)
     Res.push_back("-fobjc-arc-eh");
+  if (Opts.ObjCTrace)
+    Res.push_back("-fobjc-trace");
   if (!Opts.DebugPass.empty()) {
     Res.push_back("-mdebug-pass", Opts.DebugPass);
   }
@@ -1109,6 +1111,7 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
 
   Opts.AsmVerbose = Args.hasArg(OPT_masm_verbose);
   Opts.ObjCAutoRefCountExceptions = Args.hasArg(OPT_fobjc_arc_exceptions);
+  Opts.ObjCTrace = Args.hasArg(OPT_fobjc_trace);
   Opts.ObjCRuntimeHasARC = Args.hasArg(OPT_fobjc_runtime_has_arc);
   Opts.ObjCRuntimeHasTerminate = Args.hasArg(OPT_fobjc_runtime_has_terminate);
   Opts.CUDAIsDevice = Args.hasArg(OPT_fcuda_is_device);