5 files changed, 20 insertions, 3 deletions
diff --git a/clang/lib/CodeGen/CGBlocks.cpp b/clang/lib/CodeGen/CGBlocks.cpp
index ce2a1938706..15b08d476c7 100644
--- a/clang/lib/CodeGen/CGBlocks.cpp
+++ b/clang/lib/CodeGen/CGBlocks.cpp
@@ -1121,7 +1121,7 @@ CodeGenFunction::GenerateBlockFunction(GlobalDecl GD,
   const CGFunctionInfo &fnInfo = CGM.getTypes().arrangeFreeFunctionDeclaration(
       fnType->getReturnType(), args, fnType->getExtInfo(),
       fnType->isVariadic());
-  if (CGM.ReturnTypeUsesSRet(fnInfo))
+  if (CGM.ReturnSlotInterferesWithArgs(fnInfo))
     blockInfo.UsesStret = true;
 
   llvm::FunctionType *fnLLVMType = CGM.getTypes().GetFunctionType(fnInfo);
diff --git a/clang/lib/CodeGen/CGCall.cpp b/clang/lib/CodeGen/CGCall.cpp
index 6d5324d4a13..6bef76934e6 100644
--- a/clang/lib/CodeGen/CGCall.cpp
+++ b/clang/lib/CodeGen/CGCall.cpp
@@ -878,6 +878,11 @@ bool CodeGenModule::ReturnTypeUsesSRet(const CGFunctionInfo &FI) {
   return FI.getReturnInfo().isIndirect();
 }
 
+bool CodeGenModule::ReturnSlotInterferesWithArgs(const CGFunctionInfo &FI) {
+  return ReturnTypeUsesSRet(FI) &&
+         getTargetCodeGenInfo().doesReturnSlotInterfereWithArgs();
+}
+
 bool CodeGenModule::ReturnTypeUsesFPRet(QualType ResultType) {
   if (const BuiltinType *BT = ResultType->getAs<BuiltinType>()) {
     switch (BT->getKind()) {
diff --git a/clang/lib/CodeGen/CGObjCMac.cpp b/clang/lib/CodeGen/CGObjCMac.cpp
index 10199c8dfcf..51fbbed32c6 100644
--- a/clang/lib/CodeGen/CGObjCMac.cpp
+++ b/clang/lib/CodeGen/CGObjCMac.cpp
@@ -1881,7 +1881,7 @@ CGObjCCommonMac::EmitMessageSend(CodeGen::CodeGenFunction &CGF,
   NullReturnState nullReturn;
 
   llvm::Constant *Fn = NULL;
-  if (CGM.ReturnTypeUsesSRet(MSI.CallInfo)) {
+  if (CGM.ReturnSlotInterferesWithArgs(MSI.CallInfo)) {
     if (!IsSuper) nullReturn.init(CGF, Arg0);
     Fn = (ObjCABI == 2) ?  ObjCTypes.getSendStretFn2(IsSuper)
       : ObjCTypes.getSendStretFn(IsSuper);
@@ -1892,6 +1892,10 @@ CGObjCCommonMac::EmitMessageSend(CodeGen::CodeGenFunction &CGF,
     Fn = (ObjCABI == 2) ? ObjCTypes.getSendFp2RetFn2(IsSuper)
       : ObjCTypes.getSendFp2retFn(IsSuper);
   } else {
+    // arm64 uses objc_msgSend for stret methods and yet null receiver check
+    // must be made for it.
+    if (!IsSuper && CGM.ReturnTypeUsesSRet(MSI.CallInfo))
+      nullReturn.init(CGF, Arg0);
     Fn = (ObjCABI == 2) ? ObjCTypes.getSendFn2(IsSuper)
       : ObjCTypes.getSendFn(IsSuper);
   }
@@ -6517,7 +6521,7 @@ CGObjCNonFragileABIMac::EmitVTableMessageSend(CodeGenFunction &CGF,
   // FIXME: don't use this for that.
   llvm::Constant *fn = 0;
   std::string messageRefName("\01l_");
-  if (CGM.ReturnTypeUsesSRet(MSI.CallInfo)) {
+  if (CGM.ReturnSlotInterferesWithArgs(MSI.CallInfo)) {
     if (isSuper) {
       fn = ObjCTypes.getMessageSendSuper2StretFixupFn();
       messageRefName += "objc_msgSendSuper2_stret_fixup";
diff --git a/clang/lib/CodeGen/CodeGenModule.h b/clang/lib/CodeGen/CodeGenModule.h
index 7694eed1a1b..0d13bdcc2fa 100644
--- a/clang/lib/CodeGen/CodeGenModule.h
+++ b/clang/lib/CodeGen/CodeGenModule.h
@@ -908,6 +908,10 @@ public:
   /// as a return type.
   bool ReturnTypeUsesSRet(const CGFunctionInfo &FI);
 
+  /// ReturnSlotInterferesWithArgs - Return true iff the given type uses an
+  /// argument slot when 'sret' is used as a return type.
+  bool ReturnSlotInterferesWithArgs(const CGFunctionInfo &FI);
+
   /// ReturnTypeUsesFPRet - Return true iff the given type uses 'fpret' when
   /// used as a return type.
   bool ReturnTypeUsesFPRet(QualType ResultType);
diff --git a/clang/lib/CodeGen/TargetInfo.h b/clang/lib/CodeGen/TargetInfo.h
index 11cae6c5aa2..6c3ab64834b 100644
--- a/clang/lib/CodeGen/TargetInfo.h
+++ b/clang/lib/CodeGen/TargetInfo.h
@@ -123,6 +123,10 @@ namespace clang {
       return Ty;
     }
 
+    /// doesReturnSlotInterfereWithArgs - Return true if the target uses an
+    /// argument slot for an 'sret' type.
+    virtual bool doesReturnSlotInterfereWithArgs() const { return true; }
+
     /// Retrieve the address of a function to call immediately before
     /// calling objc_retainAutoreleasedReturnValue.  The
     /// implementation of objc_autoreleaseReturnValue sniffs the