Add -fobjc-trace to emit a call before and after each Objective-C message send

for hooking in code flow visualisation applications.  

llvm-svn: 154321

1 files changed, 15 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();