llvm/llvm/lib/Target/LoongArch/MCTargetDesc/LoongArchAsmBackend.cpp

//===-- LoongArchAsmBackend.cpp - LoongArch Assembler Backend -*- C++ -*---===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// This file implements the LoongArchAsmBackend class.
//
//===----------------------------------------------------------------------===//

#include "LoongArchAsmBackend.h"
#include "LoongArchFixupKinds.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCAssembler.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCELFObjectWriter.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCSection.h"
#include "llvm/MC/MCValue.h"
#include "llvm/Support/EndianStream.h"
#include "llvm/Support/LEB128.h"
#include "llvm/Support/MathExtras.h"

#define DEBUG_TYPE …

usingnamespacellvm;

std::optional<MCFixupKind>
LoongArchAsmBackend::getFixupKind(StringRef Name) const { … }

const MCFixupKindInfo &
LoongArchAsmBackend::getFixupKindInfo(MCFixupKind Kind) const { … }

static void reportOutOfRangeError(MCContext &Ctx, SMLoc Loc, unsigned N) { … }

static uint64_t adjustFixupValue(const MCFixup &Fixup, uint64_t Value,
                                 MCContext &Ctx) { … }

static void fixupLeb128(MCContext &Ctx, const MCFixup &Fixup,
                        MutableArrayRef<char> Data, uint64_t Value) { … }

void LoongArchAsmBackend::applyFixup(const MCAssembler &Asm,
                                     const MCFixup &Fixup,
                                     const MCValue &Target,
                                     MutableArrayRef<char> Data, uint64_t Value,
                                     bool IsResolved,
                                     const MCSubtargetInfo *STI) const { … }

// Linker relaxation may change code size. We have to insert Nops
// for .align directive when linker relaxation enabled. So then Linker
// could satisfy alignment by removing Nops.
// The function returns the total Nops Size we need to insert.
bool LoongArchAsmBackend::shouldInsertExtraNopBytesForCodeAlign(
    const MCAlignFragment &AF, unsigned &Size) { … }

// We need to insert R_LARCH_ALIGN relocation type to indicate the
// position of Nops and the total bytes of the Nops have been inserted
// when linker relaxation enabled.
// The function inserts fixup_loongarch_align fixup which eventually will
// transfer to R_LARCH_ALIGN relocation type.
// The improved R_LARCH_ALIGN requires symbol index. The lowest 8 bits of
// addend represent alignment and the other bits of addend represent the
// maximum number of bytes to emit. The maximum number of bytes is zero
// means ignore the emit limit.
bool LoongArchAsmBackend::shouldInsertFixupForCodeAlign(MCAssembler &Asm,
                                                        MCAlignFragment &AF) { … }

bool LoongArchAsmBackend::shouldForceRelocation(const MCAssembler &Asm,
                                                const MCFixup &Fixup,
                                                const MCValue &Target,
                                                const MCSubtargetInfo *STI) { … }

static inline std::pair<MCFixupKind, MCFixupKind>
getRelocPairForSize(unsigned Size) { … }

std::pair<bool, bool> LoongArchAsmBackend::relaxLEB128(const MCAssembler &Asm,
                                                       MCLEBFragment &LF,
                                                       int64_t &Value) const { … }

bool LoongArchAsmBackend::relaxDwarfLineAddr(const MCAssembler &Asm,
                                             MCDwarfLineAddrFragment &DF,
                                             bool &WasRelaxed) const { … }

bool LoongArchAsmBackend::relaxDwarfCFA(const MCAssembler &Asm,
                                        MCDwarfCallFrameFragment &DF,
                                        bool &WasRelaxed) const { … }

bool LoongArchAsmBackend::writeNopData(raw_ostream &OS, uint64_t Count,
                                       const MCSubtargetInfo *STI) const { … }

bool LoongArchAsmBackend::handleAddSubRelocations(const MCAssembler &Asm,
                                                  const MCFragment &F,
                                                  const MCFixup &Fixup,
                                                  const MCValue &Target,
                                                  uint64_t &FixedValue) const { … }

std::unique_ptr<MCObjectTargetWriter>
LoongArchAsmBackend::createObjectTargetWriter() const { … }

MCAsmBackend *llvm::createLoongArchAsmBackend(const Target &T,
                                              const MCSubtargetInfo &STI,
                                              const MCRegisterInfo &MRI,
                                              const MCTargetOptions &Options) { … }