MS ABI x64: Don't destroy arguments twice on x64

We were destroying them in the callee, and then again in the caller.  We
should use an EH-only cleanup and disable it at the point of the call
for win64, even though we don't use inalloca.

llvm-svn: 207733

1 files changed, 11 insertions, 4 deletions

diff --git a/clang/lib/CodeGen/CGCall.cpp b/clang/lib/CodeGen/CGCall.cpp
index e82b6defa6b..4428b963162 100644
--- a/clang/lib/CodeGen/CGCall.cpp
+++ b/clang/lib/CodeGen/CGCall.cpp
@@ -2286,16 +2286,23 @@ void CodeGenFunction::EmitCallArg(CallArgList &args, const Expr *E,
   // In the Microsoft C++ ABI, aggregate arguments are destructed by the callee.
   // However, we still have to push an EH-only cleanup in case we unwind before
   // we make it to the call.
-  if (HasAggregateEvalKind && args.isUsingInAlloca()) {
-    assert(getTarget().getTriple().getArch() == llvm::Triple::x86);
-    AggValueSlot Slot = createPlaceholderSlot(*this, type);
+  if (HasAggregateEvalKind &&
+      CGM.getTarget().getCXXABI().areArgsDestroyedLeftToRightInCallee()) {
+    // If we're using inalloca, use the argument memory.  Otherwise, use a
+    // temporary.  Either way, the aggregate is destroyed externally in the
+    // callee.
+    AggValueSlot Slot;
+    if (args.isUsingInAlloca())
+      Slot = createPlaceholderSlot(*this, type);
+    else
+      Slot = CreateAggTemp(type, "agg.tmp");
     Slot.setExternallyDestructed();
     EmitAggExpr(E, Slot);
     RValue RV = Slot.asRValue();
     args.add(RV, type);
 
     const CXXRecordDecl *RD = type->getAsCXXRecordDecl();
-    if (RD->hasNonTrivialDestructor()) {
+    if (RD && RD->hasNonTrivialDestructor()) {
       // Create a no-op GEP between the placeholder and the cleanup so we can
       // RAUW it successfully.  It also serves as a marker of the first
       // instruction where the cleanup is active.