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// SPDX-License-Identifier: GPL-3.0-or-later
#include "rcc/CodeGen/FrameIndexElimination.h"
#include "rcc/CodeGen/MachineBasicBlock.h"
#include "rcc/CodeGen/MachineFunction.h"
#include "rcc/CodeGen/MachineInstr.h"
#include "rcc/CodeGen/MachineMemOperand.h"
#include "rcc/CodeGen/MachineOperand.h"
#include "rcc/CodeGen/RegisterScavenger.h"
#include "rcc/CodeGen/TargetFrameLowering.h"
#include <cstddef>
#include <utility>
namespace rcc {
Expected<bool> eliminateFrameIndices(MachineFunction &Function, const TargetDescription &Target,
const TargetFrameLowering &FrameLowering,
RegisterScavenger &Scavenger) {
bool Changed = false;
for (MachineBasicBlock *Block = Function.firstBlock(); Block != nullptr; Block = Block->next()) {
for (MachineInstr *Instruction = Block->firstInstruction(); Instruction != nullptr;) {
MachineInstr *Next = Instruction->next();
for (std::size_t Index = 0; Index < Instruction->operandCount(); ++Index) {
if (Instruction->operandAt(Index)->kind() != MachineOperand::Kind::FrameIndex)
continue;
auto Eliminated =
FrameLowering.eliminateFrameIndex(*Instruction, Index, Function, Target, Scavenger);
if (!Eliminated)
return std::unexpected(Eliminated.error());
Changed = true;
}
for (std::size_t Index = 0; Index < Instruction->memOperands().size(); ++Index) {
const MachineMemOperand *Memory = Instruction->memOperands()[Index];
const auto Frame = Memory->description().Base.frameIndex();
if (!Frame)
continue;
auto Reference = FrameLowering.getFrameIndexReference(Function, *Instruction, *Frame,
Memory->description().Offset);
if (!Reference)
return std::unexpected(Reference.error());
MachineMemOperandDesc Description = Memory->description();
Description.Base = MemoryBase::stack();
Description.Offset = Reference->Offset;
auto Replacement = Function.createMemOperand(std::move(Description));
if (!Replacement)
return std::unexpected(Replacement.error());
auto Replaced = Instruction->replaceMemOperand(Index, **Replacement);
if (!Replaced)
return std::unexpected(Replaced.error());
Changed = true;
}
Instruction = Next;
}
}
return Changed;
}
} // namespace rcc
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