AArch64ELFObjectWriter.cpp

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//===-- AArch64ELFObjectWriter.cpp - AArch64 ELF Writer -------------------===//
//
// 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 handles ELF-specific object emission, converting LLVM's internal
// fixups into the appropriate relocations.
//
//===----------------------------------------------------------------------===//
 
#include "MCTargetDesc/AArch64FixupKinds.h"
#include "MCTargetDesc/AArch64MCAsmInfo.h"
#include "MCTargetDesc/AArch64MCTargetDesc.h"
#include "llvm/BinaryFormat/ELF.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCELFObjectWriter.h"
#include "llvm/MC/MCFixup.h"
#include "llvm/MC/MCObjectWriter.h"
#include "llvm/MC/MCSymbolELF.h"
#include "llvm/MC/MCValue.h"
#include "llvm/Support/ErrorHandling.h"
#include <cassert>
#include <cstdint>
 
using namespace llvm;
 
namespace {
 
class AArch64ELFObjectWriter : public MCELFObjectTargetWriter {
public:
  AArch64ELFObjectWriter(uint8_t OSABI, bool IsILP32);
 
  ~AArch64ELFObjectWriter() override = default;
 
protected:
  unsigned getRelocType(const MCFixup &, const MCValue &,
                        bool IsPCRel) const override;
  bool needsRelocateWithSymbol(const MCValue &, unsigned Type) const override;
  bool isNonILP32reloc(const MCFixup &Fixup, AArch64::Specifier RefKind) const;
  void sortRelocs(std::vector<ELFRelocationEntry> &Relocs) override;
 
  bool IsILP32;
};
 
} // end anonymous namespace
 
AArch64ELFObjectWriter::AArch64ELFObjectWriter(uint8_t OSABI, bool IsILP32)
    : MCELFObjectTargetWriter(/*Is64Bit*/ !IsILP32, OSABI, ELF::EM_AARCH64,
                              /*HasRelocationAddend*/ true),
      IsILP32(IsILP32) {}
 
#define R_CLS(rtype)                                                           \
  IsILP32 ? ELF::R_AARCH64_P32_##rtype : ELF::R_AARCH64_##rtype
 
// assumes IsILP32 is true
bool AArch64ELFObjectWriter::isNonILP32reloc(const MCFixup &Fixup,
                                             AArch64::Specifier RefKind) const {
  if (Fixup.getKind() != AArch64::fixup_aarch64_movw)
    return false;
  switch (RefKind) {
  case AArch64::S_ABS_G3:
  case AArch64::S_ABS_G2:
  case AArch64::S_ABS_G2_S:
  case AArch64::S_ABS_G2_NC:
  case AArch64::S_ABS_G1_S:
  case AArch64::S_ABS_G1_NC:
  case AArch64::S_DTPREL_G2:
  case AArch64::S_DTPREL_G1_NC:
  case AArch64::S_TPREL_G2:
  case AArch64::S_TPREL_G1_NC:
  case AArch64::S_GOTTPREL_G1:
  case AArch64::S_GOTTPREL_G0_NC:
    reportError(Fixup.getLoc(),
                "absolute MOV relocation is not supported in ILP32");
    return true;
  default:
    return false;
  }
  return false;
}
 
unsigned AArch64ELFObjectWriter::getRelocType(const MCFixup &Fixup,
                                              const MCValue &Target,
                                              bool IsPCRel) const {
  auto Kind = Fixup.getKind();
  AArch64::Specifier RefKind =
      static_cast<AArch64::Specifier>(Target.getSpecifier());
  AArch64::Specifier SymLoc = AArch64::getSymbolLoc(RefKind);
  bool IsNC = AArch64::isNotChecked(RefKind);
 
  switch (SymLoc) {
  case AArch64::S_DTPREL:
  case AArch64::S_GOTTPREL:
  case AArch64::S_TPREL:
  case AArch64::S_TLSDESC:
  case AArch64::S_TLSDESC_AUTH:
    if (auto *SA = const_cast<MCSymbol *>(Target.getAddSym()))
      static_cast<MCSymbolELF *>(SA)->setType(ELF::STT_TLS);
    break;
  default:
    break;
  }
 
  // Extract the relocation type from the fixup kind, after applying STT_TLS as
  // needed.
  if (mc::isRelocation(Fixup.getKind()))
    return Kind;
 
  if (IsPCRel) {
    switch (Kind) {
    case FK_Data_1:
      reportError(Fixup.getLoc(), "1-byte data relocations not supported");
      return ELF::R_AARCH64_NONE;
    case FK_Data_2:
      return R_CLS(PREL16);
    case FK_Data_4: {
      return Target.getSpecifier() == AArch64::S_PLT ? R_CLS(PLT32)
                                                     : R_CLS(PREL32);
    }
    case FK_Data_8:
      if (IsILP32) {
        reportError(Fixup.getLoc(), "8 byte PC relative data "
                                    "relocation is not supported in ILP32");
        return ELF::R_AARCH64_NONE;
      }
      return ELF::R_AARCH64_PREL64;
    case AArch64::fixup_aarch64_pcrel_adr_imm21:
      if (SymLoc == AArch64::S_GOT_AUTH) {
        if (IsILP32) {
          reportError(Fixup.getLoc(),
                      "ADR AUTH relocation is not supported in ILP32");
          return ELF::R_AARCH64_NONE;
        }
        return ELF::R_AARCH64_AUTH_GOT_ADR_PREL_LO21;
      }
      if (SymLoc != AArch64::S_ABS)
        reportError(Fixup.getLoc(), "invalid symbol kind for ADR relocation");
      return R_CLS(ADR_PREL_LO21);
    case AArch64::fixup_aarch64_pcrel_adrp_imm21:
      if (SymLoc == AArch64::S_ABS && !IsNC)
        return R_CLS(ADR_PREL_PG_HI21);
      if (SymLoc == AArch64::S_ABS && IsNC) {
        if (IsILP32) {
          reportError(Fixup.getLoc(),
                      "invalid fixup for 32-bit pcrel ADRP instruction "
                      "VK_ABS VK_NC");
          return ELF::R_AARCH64_NONE;
        }
        return ELF::R_AARCH64_ADR_PREL_PG_HI21_NC;
      }
      if (SymLoc == AArch64::S_GOT && !IsNC)
        return R_CLS(ADR_GOT_PAGE);
      if (SymLoc == AArch64::S_GOT_AUTH && !IsNC) {
        if (IsILP32) {
          reportError(Fixup.getLoc(),
                      "ADRP AUTH relocation is not supported in ILP32");
          return ELF::R_AARCH64_NONE;
        }
        return ELF::R_AARCH64_AUTH_ADR_GOT_PAGE;
      }
      if (SymLoc == AArch64::S_GOTTPREL && !IsNC)
        return R_CLS(TLSIE_ADR_GOTTPREL_PAGE21);
      if (SymLoc == AArch64::S_TLSDESC && !IsNC)
        return R_CLS(TLSDESC_ADR_PAGE21);
      if (SymLoc == AArch64::S_TLSDESC_AUTH && !IsNC) {
        if (IsILP32) {
          reportError(Fixup.getLoc(),
                      "ADRP AUTH relocation is not supported in ILP32");
          return ELF::R_AARCH64_NONE;
        }
        return ELF::R_AARCH64_AUTH_TLSDESC_ADR_PAGE21;
      }
      reportError(Fixup.getLoc(), "invalid symbol kind for ADRP relocation");
      return ELF::R_AARCH64_NONE;
    case AArch64::fixup_aarch64_pcrel_branch26:
      return R_CLS(JUMP26);
    case AArch64::fixup_aarch64_pcrel_call26:
      return R_CLS(CALL26);
    case AArch64::fixup_aarch64_ldr_pcrel_imm19:
      if (SymLoc == AArch64::S_GOTTPREL)
        return R_CLS(TLSIE_LD_GOTTPREL_PREL19);
      if (SymLoc == AArch64::S_GOT)
        return R_CLS(GOT_LD_PREL19);
      if (SymLoc == AArch64::S_GOT_AUTH) {
        if (IsILP32) {
          reportError(Fixup.getLoc(),
                      "LDR AUTH relocation is not supported in ILP32");
          return ELF::R_AARCH64_NONE;
        }
        return ELF::R_AARCH64_AUTH_GOT_LD_PREL19;
      }
      return R_CLS(LD_PREL_LO19);
    case AArch64::fixup_aarch64_pcrel_branch14:
      return R_CLS(TSTBR14);
    case AArch64::fixup_aarch64_pcrel_branch16:
      reportError(Fixup.getLoc(),
                  "relocation of PAC/AUT instructions is not supported");
      return ELF::R_AARCH64_NONE;
    case AArch64::fixup_aarch64_pcrel_branch9:
      reportError(
          Fixup.getLoc(),
          "relocation of compare-and-branch instructions not supported");
      return ELF::R_AARCH64_NONE;
    case AArch64::fixup_aarch64_pcrel_branch19:
      return R_CLS(CONDBR19);
    default:
      reportError(Fixup.getLoc(), "Unsupported pc-relative fixup kind");
      return ELF::R_AARCH64_NONE;
    }
  } else {
    if (IsILP32 && isNonILP32reloc(Fixup, RefKind))
      return ELF::R_AARCH64_NONE;
    switch (Fixup.getKind()) {
    case FK_Data_1:
      reportError(Fixup.getLoc(), "1-byte data relocations not supported");
      return ELF::R_AARCH64_NONE;
    case FK_Data_2:
      return R_CLS(ABS16);
    case FK_Data_4:
      return (!IsILP32 && Target.getSpecifier() == AArch64::S_GOTPCREL)
                 ? ELF::R_AARCH64_GOTPCREL32
                 : R_CLS(ABS32);
    case FK_Data_8: {
      if (IsILP32) {
        reportError(
            Fixup.getLoc(),
            "8 byte absolute data relocation is not supported in ILP32");
        return ELF::R_AARCH64_NONE;
      }
      if (RefKind == AArch64::S_AUTH || RefKind == AArch64::S_AUTHADDR)
        return ELF::R_AARCH64_AUTH_ABS64;
      return ELF::R_AARCH64_ABS64;
    }
    case AArch64::fixup_aarch64_add_imm12:
      if (RefKind == AArch64::S_DTPREL_HI12)
        return R_CLS(TLSLD_ADD_DTPREL_HI12);
      if (RefKind == AArch64::S_TPREL_HI12)
        return R_CLS(TLSLE_ADD_TPREL_HI12);
      if (RefKind == AArch64::S_DTPREL_LO12_NC)
        return R_CLS(TLSLD_ADD_DTPREL_LO12_NC);
      if (RefKind == AArch64::S_DTPREL_LO12)
        return R_CLS(TLSLD_ADD_DTPREL_LO12);
      if (RefKind == AArch64::S_TPREL_LO12_NC)
        return R_CLS(TLSLE_ADD_TPREL_LO12_NC);
      if (RefKind == AArch64::S_TPREL_LO12)
        return R_CLS(TLSLE_ADD_TPREL_LO12);
      if (RefKind == AArch64::S_TLSDESC_LO12)
        return R_CLS(TLSDESC_ADD_LO12);
      if (RefKind == AArch64::S_TLSDESC_AUTH_LO12) {
        if (IsILP32) {
          reportError(Fixup.getLoc(),
                      "ADD AUTH relocation is not supported in ILP32");
          return ELF::R_AARCH64_NONE;
        }
        return ELF::R_AARCH64_AUTH_TLSDESC_ADD_LO12;
      }
      if (RefKind == AArch64::S_GOT_AUTH_LO12 && IsNC) {
        if (IsILP32) {
          reportError(Fixup.getLoc(),
                      "ADD AUTH relocation is not supported in ILP32");
          return ELF::R_AARCH64_NONE;
        }
        return ELF::R_AARCH64_AUTH_GOT_ADD_LO12_NC;
      }
      if (SymLoc == AArch64::S_ABS && IsNC)
        return R_CLS(ADD_ABS_LO12_NC);
 
      reportError(Fixup.getLoc(), "invalid fixup for add (uimm12) instruction");
      return ELF::R_AARCH64_NONE;
    case AArch64::fixup_aarch64_ldst_imm12_scale1:
      if (SymLoc == AArch64::S_ABS && IsNC)
        return R_CLS(LDST8_ABS_LO12_NC);
      if (SymLoc == AArch64::S_DTPREL && !IsNC)
        return R_CLS(TLSLD_LDST8_DTPREL_LO12);
      if (SymLoc == AArch64::S_DTPREL && IsNC)
        return R_CLS(TLSLD_LDST8_DTPREL_LO12_NC);
      if (SymLoc == AArch64::S_TPREL && !IsNC)
        return R_CLS(TLSLE_LDST8_TPREL_LO12);
      if (SymLoc == AArch64::S_TPREL && IsNC)
        return R_CLS(TLSLE_LDST8_TPREL_LO12_NC);
 
      reportError(Fixup.getLoc(),
                  "invalid fixup for 8-bit load/store instruction");
      return ELF::R_AARCH64_NONE;
    case AArch64::fixup_aarch64_ldst_imm12_scale2:
      if (SymLoc == AArch64::S_ABS && IsNC)
        return R_CLS(LDST16_ABS_LO12_NC);
      if (SymLoc == AArch64::S_DTPREL && !IsNC)
        return R_CLS(TLSLD_LDST16_DTPREL_LO12);
      if (SymLoc == AArch64::S_DTPREL && IsNC)
        return R_CLS(TLSLD_LDST16_DTPREL_LO12_NC);
      if (SymLoc == AArch64::S_TPREL && !IsNC)
        return R_CLS(TLSLE_LDST16_TPREL_LO12);
      if (SymLoc == AArch64::S_TPREL && IsNC)
        return R_CLS(TLSLE_LDST16_TPREL_LO12_NC);
 
      reportError(Fixup.getLoc(),
                  "invalid fixup for 16-bit load/store instruction");
      return ELF::R_AARCH64_NONE;
    case AArch64::fixup_aarch64_ldst_imm12_scale4:
      if (SymLoc == AArch64::S_ABS && IsNC)
        return R_CLS(LDST32_ABS_LO12_NC);
      if (SymLoc == AArch64::S_DTPREL && !IsNC)
        return R_CLS(TLSLD_LDST32_DTPREL_LO12);
      if (SymLoc == AArch64::S_DTPREL && IsNC)
        return R_CLS(TLSLD_LDST32_DTPREL_LO12_NC);
      if (SymLoc == AArch64::S_TPREL && !IsNC)
        return R_CLS(TLSLE_LDST32_TPREL_LO12);
      if (SymLoc == AArch64::S_TPREL && IsNC)
        return R_CLS(TLSLE_LDST32_TPREL_LO12_NC);
      if (SymLoc == AArch64::S_GOT && IsNC) {
        if (IsILP32)
          return ELF::R_AARCH64_P32_LD32_GOT_LO12_NC;
        reportError(Fixup.getLoc(), "4 byte unchecked GOT load/store "
                                    "relocation is not supported in LP64");
        return ELF::R_AARCH64_NONE;
      }
      if (SymLoc == AArch64::S_GOT && !IsNC) {
        if (IsILP32) {
          reportError(
              Fixup.getLoc(),
              "4 byte checked GOT load/store relocation is not supported");
        }
        return ELF::R_AARCH64_NONE;
      }
      if (SymLoc == AArch64::S_GOTTPREL && IsNC) {
        if (IsILP32)
          return ELF::R_AARCH64_P32_TLSIE_LD32_GOTTPREL_LO12_NC;
        reportError(Fixup.getLoc(), "32-bit load/store "
                                    "relocation is not supported in LP64");
        return ELF::R_AARCH64_NONE;
      }
      if (SymLoc == AArch64::S_TLSDESC && !IsNC) {
        if (IsILP32)
          return ELF::R_AARCH64_P32_TLSDESC_LD32_LO12;
        reportError(
            Fixup.getLoc(),
            "4 byte TLSDESC load/store relocation is not supported in LP64");
        return ELF::R_AARCH64_NONE;
      }
 
      reportError(Fixup.getLoc(),
                  "invalid fixup for 32-bit load/store instruction "
                  "fixup_aarch64_ldst_imm12_scale4");
      return ELF::R_AARCH64_NONE;
    case AArch64::fixup_aarch64_ldst_imm12_scale8:
      if (SymLoc == AArch64::S_ABS && IsNC)
        return R_CLS(LDST64_ABS_LO12_NC);
      if ((SymLoc == AArch64::S_GOT || SymLoc == AArch64::S_GOT_AUTH) && IsNC) {
        AArch64::Specifier AddressLoc = AArch64::getAddressFrag(RefKind);
        bool IsAuth = (SymLoc == AArch64::S_GOT_AUTH);
        if (!IsILP32) {
          if (AddressLoc == AArch64::S_LO15)
            return ELF::R_AARCH64_LD64_GOTPAGE_LO15;
          return (IsAuth ? ELF::R_AARCH64_AUTH_LD64_GOT_LO12_NC
                         : ELF::R_AARCH64_LD64_GOT_LO12_NC);
        }
        reportError(Fixup.getLoc(),
                    "64-bit load/store relocation is not supported in ILP32");
        return ELF::R_AARCH64_NONE;
      }
      if (SymLoc == AArch64::S_DTPREL && !IsNC)
        return R_CLS(TLSLD_LDST64_DTPREL_LO12);
      if (SymLoc == AArch64::S_DTPREL && IsNC)
        return R_CLS(TLSLD_LDST64_DTPREL_LO12_NC);
      if (SymLoc == AArch64::S_TPREL && !IsNC)
        return R_CLS(TLSLE_LDST64_TPREL_LO12);
      if (SymLoc == AArch64::S_TPREL && IsNC)
        return R_CLS(TLSLE_LDST64_TPREL_LO12_NC);
      if (SymLoc == AArch64::S_GOTTPREL && IsNC) {
        if (!IsILP32)
          return ELF::R_AARCH64_TLSIE_LD64_GOTTPREL_LO12_NC;
        reportError(Fixup.getLoc(),
                    "64-bit load/store relocation is not supported in ILP32");
        return ELF::R_AARCH64_NONE;
      }
      if (SymLoc == AArch64::S_TLSDESC) {
        if (!IsILP32)
          return ELF::R_AARCH64_TLSDESC_LD64_LO12;
        reportError(Fixup.getLoc(),
                    "64-bit load/store relocation is not supported in ILP32");
        return ELF::R_AARCH64_NONE;
      }
      if (SymLoc == AArch64::S_TLSDESC_AUTH) {
        if (!IsILP32)
          return ELF::R_AARCH64_AUTH_TLSDESC_LD64_LO12;
        reportError(
            Fixup.getLoc(),
            "64-bit load/store AUTH relocation is not supported in ILP32");
        return ELF::R_AARCH64_NONE;
      }
      reportError(Fixup.getLoc(),
                  "invalid fixup for 64-bit load/store instruction");
      return ELF::R_AARCH64_NONE;
    case AArch64::fixup_aarch64_ldst_imm12_scale16:
      if (SymLoc == AArch64::S_ABS && IsNC)
        return R_CLS(LDST128_ABS_LO12_NC);
      if (SymLoc == AArch64::S_DTPREL && !IsNC)
        return R_CLS(TLSLD_LDST128_DTPREL_LO12);
      if (SymLoc == AArch64::S_DTPREL && IsNC)
        return R_CLS(TLSLD_LDST128_DTPREL_LO12_NC);
      if (SymLoc == AArch64::S_TPREL && !IsNC)
        return R_CLS(TLSLE_LDST128_TPREL_LO12);
      if (SymLoc == AArch64::S_TPREL && IsNC)
        return R_CLS(TLSLE_LDST128_TPREL_LO12_NC);
 
      reportError(Fixup.getLoc(),
                  "invalid fixup for 128-bit load/store instruction");
      return ELF::R_AARCH64_NONE;
    // ILP32 case not reached here, tested with isNonILP32reloc
    case AArch64::fixup_aarch64_movw:
      if (RefKind == AArch64::S_ABS_G3)
        return ELF::R_AARCH64_MOVW_UABS_G3;
      if (RefKind == AArch64::S_ABS_G2)
        return ELF::R_AARCH64_MOVW_UABS_G2;
      if (RefKind == AArch64::S_ABS_G2_S)
        return ELF::R_AARCH64_MOVW_SABS_G2;
      if (RefKind == AArch64::S_ABS_G2_NC)
        return ELF::R_AARCH64_MOVW_UABS_G2_NC;
      if (RefKind == AArch64::S_ABS_G1)
        return R_CLS(MOVW_UABS_G1);
      if (RefKind == AArch64::S_ABS_G1_S)
        return ELF::R_AARCH64_MOVW_SABS_G1;
      if (RefKind == AArch64::S_ABS_G1_NC)
        return ELF::R_AARCH64_MOVW_UABS_G1_NC;
      if (RefKind == AArch64::S_ABS_G0)
        return R_CLS(MOVW_UABS_G0);
      if (RefKind == AArch64::S_ABS_G0_S)
        return R_CLS(MOVW_SABS_G0);
      if (RefKind == AArch64::S_ABS_G0_NC)
        return R_CLS(MOVW_UABS_G0_NC);
      if (RefKind == AArch64::S_PREL_G3)
        return ELF::R_AARCH64_MOVW_PREL_G3;
      if (RefKind == AArch64::S_PREL_G2)
        return ELF::R_AARCH64_MOVW_PREL_G2;
      if (RefKind == AArch64::S_PREL_G2_NC)
        return ELF::R_AARCH64_MOVW_PREL_G2_NC;
      if (RefKind == AArch64::S_PREL_G1)
        return R_CLS(MOVW_PREL_G1);
      if (RefKind == AArch64::S_PREL_G1_NC)
        return ELF::R_AARCH64_MOVW_PREL_G1_NC;
      if (RefKind == AArch64::S_PREL_G0)
        return R_CLS(MOVW_PREL_G0);
      if (RefKind == AArch64::S_PREL_G0_NC)
        return R_CLS(MOVW_PREL_G0_NC);
      if (RefKind == AArch64::S_DTPREL_G2)
        return ELF::R_AARCH64_TLSLD_MOVW_DTPREL_G2;
      if (RefKind == AArch64::S_DTPREL_G1)
        return R_CLS(TLSLD_MOVW_DTPREL_G1);
      if (RefKind == AArch64::S_DTPREL_G1_NC)
        return ELF::R_AARCH64_TLSLD_MOVW_DTPREL_G1_NC;
      if (RefKind == AArch64::S_DTPREL_G0)
        return R_CLS(TLSLD_MOVW_DTPREL_G0);
      if (RefKind == AArch64::S_DTPREL_G0_NC)
        return R_CLS(TLSLD_MOVW_DTPREL_G0_NC);
      if (RefKind == AArch64::S_TPREL_G2)
        return ELF::R_AARCH64_TLSLE_MOVW_TPREL_G2;
      if (RefKind == AArch64::S_TPREL_G1)
        return R_CLS(TLSLE_MOVW_TPREL_G1);
      if (RefKind == AArch64::S_TPREL_G1_NC)
        return ELF::R_AARCH64_TLSLE_MOVW_TPREL_G1_NC;
      if (RefKind == AArch64::S_TPREL_G0)
        return R_CLS(TLSLE_MOVW_TPREL_G0);
      if (RefKind == AArch64::S_TPREL_G0_NC)
        return R_CLS(TLSLE_MOVW_TPREL_G0_NC);
      if (RefKind == AArch64::S_GOTTPREL_G1)
        return ELF::R_AARCH64_TLSIE_MOVW_GOTTPREL_G1;
      if (RefKind == AArch64::S_GOTTPREL_G0_NC)
        return ELF::R_AARCH64_TLSIE_MOVW_GOTTPREL_G0_NC;
      reportError(Fixup.getLoc(), "invalid fixup for movz/movk instruction");
      return ELF::R_AARCH64_NONE;
    default:
      reportError(Fixup.getLoc(), "Unknown ELF relocation type");
      return ELF::R_AARCH64_NONE;
    }
  }
 
  llvm_unreachable("Unimplemented fixup -> relocation");
}
 
bool AArch64ELFObjectWriter::needsRelocateWithSymbol(const MCValue &Val,
                                                     unsigned) const {
  // For memory-tagged symbols, ensure that the relocation uses the symbol. For
  // tagged symbols, we emit an empty relocation (R_AARCH64_NONE) in a special
  // section (SHT_AARCH64_MEMTAG_GLOBALS_STATIC) to indicate to the linker that
  // this global needs to be tagged. In addition, the linker needs to know
  // whether to emit a special addend when relocating `end` symbols, and this
  // can only be determined by the attributes of the symbol itself.
  if (Val.getAddSym() &&
      static_cast<const MCSymbolELF *>(Val.getAddSym())->isMemtag())
    return true;
 
  if ((Val.getSpecifier() & AArch64::S_GOT) == AArch64::S_GOT)
    return true;
  return is_contained({AArch64::S_GOTPCREL, AArch64::S_PLT},
                      Val.getSpecifier());
}
 
void AArch64ELFObjectWriter::sortRelocs(
    std::vector<ELFRelocationEntry> &Relocs) {
  // PATCHINST relocations should be applied last because they may overwrite the
  // whole instruction and so should take precedence over other relocations that
  // modify operands of the original instruction.
  std::stable_partition(Relocs.begin(), Relocs.end(),
                        [](const ELFRelocationEntry &R) {
                          return R.Type != ELF::R_AARCH64_PATCHINST;
                        });
}
 
std::unique_ptr<MCObjectTargetWriter>
llvm::createAArch64ELFObjectWriter(uint8_t OSABI, bool IsILP32) {
  return std::make_unique<AArch64ELFObjectWriter>(OSABI, IsILP32);
}