Restore r184205 and associated commits (after commit of r185290)
This allows clang to use the backend parameter attribute 'returned' when generating 'this'-returning constructors and destructors in ARM and MSVC C++ ABIs.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@185291 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGCall.cpp b/lib/CodeGen/CGCall.cpp
index cb5c78a..7d60773 100644
--- a/lib/CodeGen/CGCall.cpp
+++ b/lib/CodeGen/CGCall.cpp
@@ -200,7 +200,10 @@
CXXCtorType ctorKind) {
SmallVector<CanQualType, 16> argTypes;
argTypes.push_back(GetThisType(Context, D->getParent()));
- CanQualType resultType = Context.VoidTy;
+
+ GlobalDecl GD(D, ctorKind);
+ CanQualType resultType =
+ TheCXXABI.HasThisReturn(GD) ? argTypes.front() : Context.VoidTy;
TheCXXABI.BuildConstructorSignature(D, ctorKind, resultType, argTypes);
@@ -225,7 +228,10 @@
CXXDtorType dtorKind) {
SmallVector<CanQualType, 2> argTypes;
argTypes.push_back(GetThisType(Context, D->getParent()));
- CanQualType resultType = Context.VoidTy;
+
+ GlobalDecl GD(D, dtorKind);
+ CanQualType resultType =
+ TheCXXABI.HasThisReturn(GD) ? argTypes.front() : Context.VoidTy;
TheCXXABI.BuildDestructorSignature(D, dtorKind, resultType, argTypes);
@@ -1633,18 +1639,6 @@
return store;
}
-/// Check whether 'this' argument of a callsite matches 'this' of the caller.
-static bool checkThisPointer(llvm::Value *ThisArg, llvm::Value *This) {
- if (ThisArg == This)
- return true;
- // Check whether ThisArg is a bitcast of This.
- llvm::BitCastInst *Bitcast;
- if ((Bitcast = dyn_cast<llvm::BitCastInst>(ThisArg)) &&
- Bitcast->getOperand(0) == This)
- return true;
- return false;
-}
-
void CodeGenFunction::EmitFunctionEpilog(const CGFunctionInfo &FI,
bool EmitRetDbgLoc) {
// Functions with no result always return void.
@@ -1741,19 +1735,6 @@
llvm_unreachable("Invalid ABI kind for return argument");
}
- // If this function returns 'this', the last instruction is a CallInst
- // that returns 'this', and 'this' argument of the CallInst points to
- // the same object as CXXThisValue, use the return value from the CallInst.
- // We will not need to keep 'this' alive through the callsite. It also enables
- // optimizations in the backend, such as tail call optimization.
- if (CalleeWithThisReturn && CGM.getCXXABI().HasThisReturn(CurGD)) {
- llvm::BasicBlock *IP = Builder.GetInsertBlock();
- llvm::CallInst *Callsite;
- if (!IP->empty() && (Callsite = dyn_cast<llvm::CallInst>(&IP->back())) &&
- Callsite->getCalledFunction() == CalleeWithThisReturn &&
- checkThisPointer(Callsite->getOperand(0), CXXThisValue))
- RV = Builder.CreateBitCast(Callsite, RetAI.getCoerceToType());
- }
llvm::Instruction *Ret = RV ? Builder.CreateRet(RV) : Builder.CreateRetVoid();
if (!RetDbgLoc.isUnknown())
Ret->setDebugLoc(RetDbgLoc);