3 files changed, 31 insertions, 6 deletions
diff --git a/clang/lib/CodeGen/CGObjCGNU.cpp b/clang/lib/CodeGen/CGObjCGNU.cpp
index 2cae9a0ea87..5e7eec9819c 100644
--- a/clang/lib/CodeGen/CGObjCGNU.cpp
+++ b/clang/lib/CodeGen/CGObjCGNU.cpp
@@ -417,8 +417,8 @@ CGObjCGNU::GenerateMessageSend(CodeGen::CodeGenFunction &CGF,
   CallArgList ActualArgs;
 
   ActualArgs.push_back(
-	  std::make_pair(RValue::get(CGF.Builder.CreateBitCast(Receiver, IdTy)), 
-	  CGF.getContext().getObjCIdType()));
+    std::make_pair(RValue::get(CGF.Builder.CreateBitCast(Receiver, IdTy)), 
+    CGF.getContext().getObjCIdType()));
   ActualArgs.push_back(std::make_pair(RValue::get(cmd),
                                       CGF.getContext().getObjCSelType()));
   ActualArgs.insert(ActualArgs.end(), CallArgs.begin(), CallArgs.end());
@@ -427,15 +427,36 @@ CGObjCGNU::GenerateMessageSend(CodeGen::CodeGenFunction &CGF,
   const CGFunctionInfo &FnInfo = Types.getFunctionInfo(ResultType, ActualArgs);
   const llvm::FunctionType *impType = Types.GetFunctionType(FnInfo, false);
 
+  llvm::Value *imp;
   std::vector<const llvm::Type*> Params;
   Params.push_back(Receiver->getType());
   Params.push_back(SelectorTy);
-  llvm::Constant *lookupFunction = 
-    CGM.CreateRuntimeFunction(llvm::FunctionType::get(
+  // For sender-aware dispatch, we pass the sender as the third argument to a
+  // lookup function.  When sending messages from C code, the sender is nil.
+  // objc_msg_lookup_sender(id receiver, SEL selector, id sender);
+  if (CGM.getContext().getLangOptions().ObjCSenderDispatch) {
+    llvm::Value *self;
+
+    if (isa<ObjCMethodDecl>(CGF.CurFuncDecl)) {
+      self = CGF.LoadObjCSelf();
+    } else {
+      self = llvm::ConstantPointerNull::get(IdTy);
+    }
+    Params.push_back(self->getType());
+    llvm::Constant *lookupFunction = 
+      CGM.CreateRuntimeFunction(llvm::FunctionType::get(
           llvm::PointerType::getUnqual(impType), Params, true),
-        "objc_msg_lookup");
+        "objc_msg_lookup_sender");
 
-  llvm::Value *imp = CGF.Builder.CreateCall2(lookupFunction, Receiver, cmd);
+    imp = CGF.Builder.CreateCall3(lookupFunction, Receiver, cmd, self);
+  } else {
+    llvm::Constant *lookupFunction = 
+    CGM.CreateRuntimeFunction(llvm::FunctionType::get(
+        llvm::PointerType::getUnqual(impType), Params, true),
+      "objc_msg_lookup");
+
+    imp = CGF.Builder.CreateCall2(lookupFunction, Receiver, cmd);
+  }
 
   return CGF.EmitCall(FnInfo, imp, ActualArgs);
 }
diff --git a/clang/lib/Driver/Tools.cpp b/clang/lib/Driver/Tools.cpp
index fd071dfe282..abfabbb721a 100644
--- a/clang/lib/Driver/Tools.cpp
+++ b/clang/lib/Driver/Tools.cpp
@@ -479,6 +479,7 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
   Args.AddLastArg(CmdArgs, options::OPT_fno_show_column);
   Args.AddLastArg(CmdArgs, options::OPT_fobjc_gc_only);
   Args.AddLastArg(CmdArgs, options::OPT_fobjc_gc);
+  Args.AddLastArg(CmdArgs, options::OPT_fobjc_sender_dependent_dispatch);
   // FIXME: Should we remove this?
   Args.AddLastArg(CmdArgs, options::OPT_fobjc_nonfragile_abi);
   Args.AddLastArg(CmdArgs, options::OPT_fobjc_tight_layout);
diff --git a/clang/lib/Frontend/InitPreprocessor.cpp b/clang/lib/Frontend/InitPreprocessor.cpp
index 1ad9d5c8d3b..8f4cdbc5f5d 100644
--- a/clang/lib/Frontend/InitPreprocessor.cpp
+++ b/clang/lib/Frontend/InitPreprocessor.cpp
@@ -280,6 +280,9 @@ static void InitializePredefinedMacros(const TargetInfo &TI,
   if (LangOpts.ObjC2)
     DefineBuiltinMacro(Buf, "OBJC_NEW_PROPERTIES");
 
+  if (LangOpts.ObjCSenderDispatch)
+    DefineBuiltinMacro(Buf, "__OBJC_SENDER_AWARE_DISPATCH__");
+
   if (LangOpts.PascalStrings)
     DefineBuiltinMacro(Buf, "__PASCAL_STRINGS__");