MS ABI: Use the correct this arg when generating implicit array copy ctor

We assumed the last argument of the copy constructor was the this
pointer.  However, this is not the case under the MS ABI.

llvm-svn: 219775

1 files changed, 2 insertions, 3 deletions

diff --git a/clang/lib/CodeGen/CGClass.cpp b/clang/lib/CodeGen/CGClass.cpp
index d7010c7e916..1bba4a70a14 100644
--- a/clang/lib/CodeGen/CGClass.cpp
+++ b/clang/lib/CodeGen/CGClass.cpp
@@ -580,9 +580,8 @@ static void EmitMemberInitializer(CodeGenFunction &CGF,
     CXXConstructExpr *CE = dyn_cast<CXXConstructExpr>(MemberInit->getInit());
     if (BaseElementTy.isPODType(CGF.getContext()) ||
         (CE && CE->getConstructor()->isTrivial())) {
-      // Find the source pointer. We know it's the last argument because
-      // we know we're in an implicit copy constructor.
-      unsigned SrcArgIndex = Args.size() - 1;
+      unsigned SrcArgIndex =
+          CGF.CGM.getCXXABI().getSrcArgforCopyCtor(Constructor, Args);
       llvm::Value *SrcPtr
         = CGF.Builder.CreateLoad(CGF.GetAddrOfLocalVar(Args[SrcArgIndex]));
       LValue ThisRHSLV = CGF.MakeNaturalAlignAddrLValue(SrcPtr, RecordTy);