d57bba7cf8
To accommodate frame layouts that have both fixed and scalable objects on the stack, describing a stack location or offset using a pointer + uint64_t is not sufficient. For this reason, we've introduced the StackOffset class, which models both the fixed- and scalable sized offsets. The TargetFrameLowering::getFrameIndexReference is made to return a StackOffset, so that this can be used in other interfaces, such as to eliminate frame indices in PEI or to emit Debug locations for variables on the stack. This patch is purely mechanical and doesn't change the behaviour of how the result of this function is used for fixed-sized offsets. The patch adds various checks to assert that the offset has no scalable component, as frame offsets with a scalable component are not yet supported in various places. Reviewed By: arsenm Differential Revision: https://reviews.llvm.org/D90018
50 lines
1.9 KiB
C++
50 lines
1.9 KiB
C++
//===----------------------- R600FrameLowering.cpp ------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//==-----------------------------------------------------------------------===//
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#include "R600FrameLowering.h"
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#include "AMDGPUSubtarget.h"
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#include "R600RegisterInfo.h"
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#include "llvm/CodeGen/MachineFrameInfo.h"
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#include "llvm/CodeGen/MachineFunction.h"
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#include "llvm/Support/MathExtras.h"
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using namespace llvm;
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R600FrameLowering::~R600FrameLowering() = default;
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/// \returns The number of registers allocated for \p FI.
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StackOffset
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R600FrameLowering::getFrameIndexReference(const MachineFunction &MF, int FI,
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Register &FrameReg) const {
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const MachineFrameInfo &MFI = MF.getFrameInfo();
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const R600RegisterInfo *RI
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= MF.getSubtarget<R600Subtarget>().getRegisterInfo();
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// Fill in FrameReg output argument.
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FrameReg = RI->getFrameRegister(MF);
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// Start the offset at 2 so we don't overwrite work group information.
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// FIXME: We should only do this when the shader actually uses this
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// information.
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unsigned OffsetBytes = 2 * (getStackWidth(MF) * 4);
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int UpperBound = FI == -1 ? MFI.getNumObjects() : FI;
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for (int i = MFI.getObjectIndexBegin(); i < UpperBound; ++i) {
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OffsetBytes = alignTo(OffsetBytes, MFI.getObjectAlign(i));
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OffsetBytes += MFI.getObjectSize(i);
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// Each register holds 4 bytes, so we must always align the offset to at
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// least 4 bytes, so that 2 frame objects won't share the same register.
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OffsetBytes = alignTo(OffsetBytes, Align(4));
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}
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if (FI != -1)
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OffsetBytes = alignTo(OffsetBytes, MFI.getObjectAlign(FI));
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return StackOffset::getFixed(OffsetBytes / (getStackWidth(MF) * 4));
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}
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