Make variable argument intrinsics behave correctly in a Win64 CC function.
Summary:
This change makes the variable argument intrinsics, `llvm.va_start` and
`llvm.va_copy`, and the `va_arg` instruction behave as they do on Windows
inside a `CallingConv::X86_64_Win64` function. It's needed for a Clang patch
I have to add support for GCC's `__builtin_ms_va_list` constructs.
Reviewers: nadav, asl, eugenis
CC: llvm-commits
Differential Revision: http://llvm-reviews.chandlerc.com/D1622
llvm-svn: 245990
diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
index 552f92b..be08ca8 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
@@ -3099,57 +3099,13 @@
Results.push_back(Tmp1);
break;
}
- case ISD::VAARG: {
- const Value *V = cast<SrcValueSDNode>(Node->getOperand(2))->getValue();
- EVT VT = Node->getValueType(0);
- Tmp1 = Node->getOperand(0);
- Tmp2 = Node->getOperand(1);
- unsigned Align = Node->getConstantOperandVal(3);
-
- SDValue VAListLoad =
- DAG.getLoad(TLI.getPointerTy(DAG.getDataLayout()), dl, Tmp1, Tmp2,
- MachinePointerInfo(V), false, false, false, 0);
- SDValue VAList = VAListLoad;
-
- if (Align > TLI.getMinStackArgumentAlignment()) {
- assert(((Align & (Align-1)) == 0) && "Expected Align to be a power of 2");
-
- VAList = DAG.getNode(ISD::ADD, dl, VAList.getValueType(), VAList,
- DAG.getConstant(Align - 1, dl,
- VAList.getValueType()));
-
- VAList = DAG.getNode(ISD::AND, dl, VAList.getValueType(), VAList,
- DAG.getConstant(-(int64_t)Align, dl,
- VAList.getValueType()));
- }
-
- // Increment the pointer, VAList, to the next vaarg
- Tmp3 = DAG.getNode(ISD::ADD, dl, VAList.getValueType(), VAList,
- DAG.getConstant(DAG.getDataLayout().getTypeAllocSize(
- VT.getTypeForEVT(*DAG.getContext())),
- dl, VAList.getValueType()));
- // Store the incremented VAList to the legalized pointer
- Tmp3 = DAG.getStore(VAListLoad.getValue(1), dl, Tmp3, Tmp2,
- MachinePointerInfo(V), false, false, 0);
- // Load the actual argument out of the pointer VAList
- Results.push_back(DAG.getLoad(VT, dl, Tmp3, VAList, MachinePointerInfo(),
- false, false, false, 0));
+ case ISD::VAARG:
+ Results.push_back(DAG.expandVAArg(Node));
Results.push_back(Results[0].getValue(1));
break;
- }
- case ISD::VACOPY: {
- // This defaults to loading a pointer from the input and storing it to the
- // output, returning the chain.
- const Value *VD = cast<SrcValueSDNode>(Node->getOperand(3))->getValue();
- const Value *VS = cast<SrcValueSDNode>(Node->getOperand(4))->getValue();
- Tmp1 = DAG.getLoad(TLI.getPointerTy(DAG.getDataLayout()), dl,
- Node->getOperand(0), Node->getOperand(2),
- MachinePointerInfo(VS), false, false, false, 0);
- Tmp1 = DAG.getStore(Tmp1.getValue(1), dl, Tmp1, Node->getOperand(1),
- MachinePointerInfo(VD), false, false, 0);
- Results.push_back(Tmp1);
+ case ISD::VACOPY:
+ Results.push_back(DAG.expandVACopy(Node));
break;
- }
case ISD::EXTRACT_VECTOR_ELT:
if (Node->getOperand(0).getValueType().getVectorNumElements() == 1)
// This must be an access of the only element. Return it.