llvm-project/llvm/lib/Target/AMDGPU/R600FrameLowering.cpp

50 lines
1.9 KiB
C++

//===----------------------- R600FrameLowering.cpp ------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//==-----------------------------------------------------------------------===//
#include "R600FrameLowering.h"
#include "AMDGPUSubtarget.h"
#include "R600RegisterInfo.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/Support/MathExtras.h"
using namespace llvm;
R600FrameLowering::~R600FrameLowering() = default;
/// \returns The number of registers allocated for \p FI.
int R600FrameLowering::getFrameIndexReference(const MachineFunction &MF,
int FI,
unsigned &FrameReg) const {
const MachineFrameInfo &MFI = MF.getFrameInfo();
const R600RegisterInfo *RI
= MF.getSubtarget<R600Subtarget>().getRegisterInfo();
// Fill in FrameReg output argument.
FrameReg = RI->getFrameRegister(MF);
// Start the offset at 2 so we don't overwrite work group information.
// FIXME: We should only do this when the shader actually uses this
// information.
unsigned OffsetBytes = 2 * (getStackWidth(MF) * 4);
int UpperBound = FI == -1 ? MFI.getNumObjects() : FI;
for (int i = MFI.getObjectIndexBegin(); i < UpperBound; ++i) {
OffsetBytes = alignTo(OffsetBytes, MFI.getObjectAlignment(i));
OffsetBytes += MFI.getObjectSize(i);
// Each register holds 4 bytes, so we must always align the offset to at
// least 4 bytes, so that 2 frame objects won't share the same register.
OffsetBytes = alignTo(OffsetBytes, 4);
}
if (FI != -1)
OffsetBytes = alignTo(OffsetBytes, MFI.getObjectAlignment(FI));
return OffsetBytes / (getStackWidth(MF) * 4);
}