Add method MipsTargetLowering::writeVarArgRegs which copies argument registers
of vararg functions back to the stack.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166844 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/Mips/MipsISelLowering.cpp b/lib/Target/Mips/MipsISelLowering.cpp
index bbcd1890..48c7f66 100644
--- a/lib/Target/Mips/MipsISelLowering.cpp
+++ b/lib/Target/Mips/MipsISelLowering.cpp
@@ -4076,3 +4076,48 @@
MachinePointerInfo(0), MachinePointerInfo(0));
MemOpChains.push_back(Chain);
}
+
+void
+MipsTargetLowering::writeVarArgRegs(std::vector<SDValue> &OutChains,
+ const MipsCC &CC, SDValue Chain,
+ DebugLoc DL, SelectionDAG &DAG) const {
+ unsigned NumRegs = CC.numIntArgRegs();
+ const uint16_t *ArgRegs = CC.intArgRegs();
+ const CCState &CCInfo = CC.getCCInfo();
+ unsigned Idx = CCInfo.getFirstUnallocated(ArgRegs, NumRegs);
+ unsigned RegSize = CC.regSize();
+ EVT RegTy = MVT::getIntegerVT(RegSize * 8);
+ const TargetRegisterClass *RC = getRegClassFor(RegTy);
+ MachineFunction &MF = DAG.getMachineFunction();
+ MachineFrameInfo *MFI = MF.getFrameInfo();
+ MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();
+
+ // Offset of the first variable argument from stack pointer.
+ int VaArgOffset;
+
+ if (NumRegs == Idx)
+ VaArgOffset = RoundUpToAlignment(CCInfo.getNextStackOffset(), RegSize);
+ else
+ VaArgOffset =
+ (int)CC.reservedArgArea() - (int)(RegSize * (NumRegs - Idx));
+
+ // Record the frame index of the first variable argument
+ // which is a value necessary to VASTART.
+ int FI = MFI->CreateFixedObject(RegSize, VaArgOffset, true);
+ MipsFI->setVarArgsFrameIndex(FI);
+
+ // Copy the integer registers that have not been used for argument passing
+ // to the argument register save area. For O32, the save area is allocated
+ // in the caller's stack frame, while for N32/64, it is allocated in the
+ // callee's stack frame.
+ for (unsigned I = Idx; I < NumRegs; ++I, VaArgOffset += RegSize) {
+ unsigned Reg = AddLiveIn(MF, ArgRegs[I], RC);
+ SDValue ArgValue = DAG.getCopyFromReg(Chain, DL, Reg, RegTy);
+ FI = MFI->CreateFixedObject(RegSize, VaArgOffset, true);
+ SDValue PtrOff = DAG.getFrameIndex(FI, getPointerTy());
+ SDValue Store = DAG.getStore(Chain, DL, ArgValue, PtrOff,
+ MachinePointerInfo(), false, false, 0);
+ cast<StoreSDNode>(Store.getNode())->getMemOperand()->setValue(0);
+ OutChains.push_back(Store);
+ }
+}