Fangrui Song d3589edafc MCAsmBackend::applyFixup: Change Data to indicate the relocated location
`Data` now references the first byte of the fixup offset within the current fragment.

MCAssembler::layout asserts that the fixup offset is within either the
fixed-size content or the optional variable-size tail, as this is the
most the generic code can validate without knowing the target-specific
fixup size.

Many backends applyFixup assert
```
assert(Offset + Size <= F.getSize() && "Invalid fixup offset!");
```

This refactoring allows a subsequent change to move the fixed-size
content outside of MCSection::ContentStorage, fixing the
-fsanitize=pointer-overflow issue of #150846

Pull Request: https://github.com/llvm/llvm-project/pull/151724
2025-08-02 09:27:06 -07:00

55 lines
2.1 KiB
C++

//===-- CSKYAsmBackend.h - CSKY Assembler Backend -------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIB_TARGET_CSKY_MCTARGETDESC_CSKYASMBACKEND_H
#define LLVM_LIB_TARGET_CSKY_MCTARGETDESC_CSKYASMBACKEND_H
#include "MCTargetDesc/CSKYFixupKinds.h"
#include "llvm/MC/MCAsmBackend.h"
#include "llvm/MC/MCSubtargetInfo.h"
#include "llvm/MC/MCTargetOptions.h"
namespace llvm {
class CSKYAsmBackend : public MCAsmBackend {
public:
CSKYAsmBackend(const MCSubtargetInfo &STI, const MCTargetOptions &OP)
: MCAsmBackend(llvm::endianness::little) {}
std::optional<bool> evaluateFixup(const MCFragment &, MCFixup &, MCValue &,
uint64_t &) override;
void applyFixup(const MCFragment &, const MCFixup &, const MCValue &Target,
uint8_t *Data, uint64_t Value, bool IsResolved) override;
MCFixupKindInfo getFixupKindInfo(MCFixupKind Kind) const override;
bool fixupNeedsRelaxation(const MCFixup &Fixup,
uint64_t Value) const override;
bool mayNeedRelaxation(unsigned Opcode, ArrayRef<MCOperand> Operands,
const MCSubtargetInfo &STI) const override;
void relaxInstruction(MCInst &Inst,
const MCSubtargetInfo &STI) const override;
bool fixupNeedsRelaxationAdvanced(const MCFragment &, const MCFixup &,
const MCValue &, uint64_t,
bool) const override;
bool writeNopData(raw_ostream &OS, uint64_t Count,
const MCSubtargetInfo *STI) const override;
bool shouldForceRelocation(const MCFixup &Fixup, const MCValue &Target);
std::unique_ptr<MCObjectTargetWriter>
createObjectTargetWriter() const override;
};
} // namespace llvm
#endif // LLVM_LIB_TARGET_CSKY_MCTARGETDESC_CSKYASMBACKEND_H