1 files changed, 12 insertions, 4 deletions
diff --git a/lib/CodeGen/CGVTables.cpp b/lib/CodeGen/CGVTables.cpp
index 891697f4cd..6acbe436c8 100644
--- a/lib/CodeGen/CGVTables.cpp
+++ b/lib/CodeGen/CGVTables.cpp
@@ -2582,8 +2582,11 @@ void CodeGenFunction::GenerateThunk(llvm::Function *Fn, GlobalDecl GD,
     
     FunctionArgs.push_back(std::make_pair(Param, Param->getType()));
   }
-  
-  StartFunction(GlobalDecl(), ResultType, Fn, FunctionArgs, SourceLocation());
+
+  const bool IsWin64 = CGM.getContext().Target.isWin64();
+
+  StartFunction(GlobalDecl(), ResultType, Fn, FunctionArgs, SourceLocation(),
+                IsWin64 ? CC_Win64ThisCall : CC_Default);
 
   CGM.getCXXABI().EmitInstanceFunctionProlog(*this);
 
@@ -2614,9 +2617,14 @@ void CodeGenFunction::GenerateThunk(llvm::Function *Fn, GlobalDecl GD,
                                    FPT->isVariadic());
   llvm::Value *Callee = CGM.GetAddrOfFunction(GD, Ty, /*ForVTable=*/true);
 
+  FunctionType::ExtInfo Info = FPT->getExtInfo();
+
+  if (IsWin64) {
+      Info = Info.withCallingConv(CC_Win64ThisCall);
+  }
+
   const CGFunctionInfo &FnInfo = 
-    CGM.getTypes().getFunctionInfo(ResultType, CallArgs,
-                                   FPT->getExtInfo());
+    CGM.getTypes().getFunctionInfo(ResultType, CallArgs, Info);
   
   // Determine whether we have a return value slot to use.
   ReturnValueSlot Slot;