When creating a this-adjustment thunk where the return value is of C++

class type (that uses a return slot), pass the return slot to the
callee directly rather than allocating new storage and trying to copy
the object. This appears to have been the cause of the remaining two
Boost.Interprocess failures.

llvm-svn: 104215

1 files changed, 9 insertions, 2 deletions

diff --git a/clang/lib/CodeGen/CGVTables.cpp b/clang/lib/CodeGen/CGVTables.cpp
index 368e2483c86..3c9b45ba8c1 100644
--- a/clang/lib/CodeGen/CGVTables.cpp
+++ b/clang/lib/CodeGen/CGVTables.cpp
@@ -2657,8 +2657,15 @@ void CodeGenFunction::GenerateThunk(llvm::Function *Fn, GlobalDecl GD,
     CGM.getTypes().getFunctionInfo(ResultType, CallArgs,
                                    FPT->getExtInfo());
   
+  // Determine whether we have a return value slot to use.
+  ReturnValueSlot Slot;
+  if (!ResultType->isVoidType() &&
+      FnInfo.getReturnInfo().getKind() == ABIArgInfo::Indirect &&
+      hasAggregateLLVMType(CurFnInfo->getReturnType()))
+    Slot = ReturnValueSlot(ReturnValue, ResultType.isVolatileQualified());
+  
   // Now emit our call.
-  RValue RV = EmitCall(FnInfo, Callee, ReturnValueSlot(), CallArgs, MD);
+  RValue RV = EmitCall(FnInfo, Callee, Slot, CallArgs, MD);
   
   if (!Thunk.Return.isEmpty()) {
     // Emit the return adjustment.
@@ -2701,7 +2708,7 @@ void CodeGenFunction::GenerateThunk(llvm::Function *Fn, GlobalDecl GD,
     RV = RValue::get(ReturnValue);
   }
 
-  if (!ResultType->isVoidType())
+  if (!ResultType->isVoidType() && Slot.isNull())
     EmitReturnOfRValue(RV, ResultType);
 
   FinishFunction();