RISCVAsmBackend.h

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//===-- RISCVAsmBackend.h - RISC-V 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_RISCV_MCTARGETDESC_RISCVASMBACKEND_H
#define LLVM_LIB_TARGET_RISCV_MCTARGETDESC_RISCVASMBACKEND_H
 
#include "MCTargetDesc/RISCVBaseInfo.h"
#include "MCTargetDesc/RISCVFixupKinds.h"
#include "MCTargetDesc/RISCVMCTargetDesc.h"
#include "llvm/MC/MCAsmBackend.h"
#include "llvm/MC/MCFixupKindInfo.h"
#include "llvm/MC/MCSubtargetInfo.h"
 
namespace llvm {
class MCAssembler;
class MCObjectTargetWriter;
class raw_ostream;
 
class RISCVAsmBackend : public MCAsmBackend {
  const MCSubtargetInfo &STI;
  uint8_t OSABI;
  bool Is64Bit;
  bool ForceRelocs = false;
  const MCTargetOptions &TargetOptions;
 
public:
  RISCVAsmBackend(const MCSubtargetInfo &STI, uint8_t OSABI, bool Is64Bit,
                  const MCTargetOptions &Options)
      : MCAsmBackend(llvm::endianness::little, RISCV::fixup_riscv_relax),
        STI(STI), OSABI(OSABI), Is64Bit(Is64Bit), TargetOptions(Options) {
    RISCVFeatures::validate(STI.getTargetTriple(), STI.getFeatureBits());
  }
  ~RISCVAsmBackend() override = default;
 
  void setForceRelocs() { ForceRelocs = true; }
 
  // Return Size with extra Nop Bytes for alignment directive in code section.
  bool shouldInsertExtraNopBytesForCodeAlign(const MCAlignFragment &AF,
                                             unsigned &Size) override;
 
  // Insert target specific fixup type for alignment directive in code section.
  bool shouldInsertFixupForCodeAlign(MCAssembler &Asm,
                                     const MCAsmLayout &Layout,
                                     MCAlignFragment &AF) override;
 
  bool evaluateTargetFixup(const MCAssembler &Asm, const MCAsmLayout &Layout,
                           const MCFixup &Fixup, const MCFragment *DF,
                           const MCValue &Target, const MCSubtargetInfo *STI,
                           uint64_t &Value, bool &WasForced) override;
 
  bool handleAddSubRelocations(const MCAsmLayout &Layout, const MCFragment &F,
                               const MCFixup &Fixup, const MCValue &Target,
                               uint64_t &FixedValue) const override;
 
  void applyFixup(const MCAssembler &Asm, const MCFixup &Fixup,
                  const MCValue &Target, MutableArrayRef<char> Data,
                  uint64_t Value, bool IsResolved,
                  const MCSubtargetInfo *STI) const override;
 
  std::unique_ptr<MCObjectTargetWriter>
  createObjectTargetWriter() const override;
 
  bool shouldForceRelocation(const MCAssembler &Asm, const MCFixup &Fixup,
                             const MCValue &Target,
                             const MCSubtargetInfo *STI) override;
 
  bool fixupNeedsRelaxation(const MCFixup &Fixup, uint64_t Value,
                            const MCRelaxableFragment *DF,
                            const MCAsmLayout &Layout) const override {
    llvm_unreachable("Handled by fixupNeedsRelaxationAdvanced");
  }
 
  bool fixupNeedsRelaxationAdvanced(const MCFixup &Fixup, bool Resolved,
                                    uint64_t Value,
                                    const MCRelaxableFragment *DF,
                                    const MCAsmLayout &Layout,
                                    const bool WasForced) const override;
 
  unsigned getNumFixupKinds() const override {
    return RISCV::NumTargetFixupKinds;
  }
 
  std::optional<MCFixupKind> getFixupKind(StringRef Name) const override;
 
  const MCFixupKindInfo &getFixupKindInfo(MCFixupKind Kind) const override;
 
  bool mayNeedRelaxation(const MCInst &Inst,
                         const MCSubtargetInfo &STI) const override;
  unsigned getRelaxedOpcode(unsigned Op) const;
 
  void relaxInstruction(MCInst &Inst,
                        const MCSubtargetInfo &STI) const override;
 
  bool relaxDwarfLineAddr(MCDwarfLineAddrFragment &DF, MCAsmLayout &Layout,
                          bool &WasRelaxed) const override;
  bool relaxDwarfCFA(MCDwarfCallFrameFragment &DF, MCAsmLayout &Layout,
                     bool &WasRelaxed) const override;
  std::pair<bool, bool> relaxLEB128(MCLEBFragment &LF, MCAsmLayout &Layout,
                                    int64_t &Value) const override;
 
  bool writeNopData(raw_ostream &OS, uint64_t Count,
                    const MCSubtargetInfo *STI) const override;
 
  const MCTargetOptions &getTargetOptions() const { return TargetOptions; }
};
}
 
#endif