text: //===-- llvm/Target/ARMTargetObjectFile.cpp - ARM Object Info Impl --------===//
  //
  // 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
  //
  //===----------------------------------------------------------------------===//
  
  #include "ARMTargetObjectFile.h"
  #include "ARMSubtarget.h"
  #include "ARMTargetMachine.h"
  #include "llvm/BinaryFormat/Dwarf.h"
  #include "llvm/BinaryFormat/ELF.h"
  #include "llvm/MC/MCAsmInfo.h"
  #include "llvm/MC/MCContext.h"
  #include "llvm/MC/MCExpr.h"
  #include "llvm/MC/MCSectionELF.h"
  #include "llvm/MC/MCTargetOptions.h"
  #include "llvm/MC/SectionKind.h"
  #include "llvm/Target/TargetMachine.h"
  #include <cassert>
  
  using namespace llvm;
  using namespace dwarf;
  
  //===----------------------------------------------------------------------===//
  //                               ELF Target
  //===----------------------------------------------------------------------===//
  
  void ARMElfTargetObjectFile::Initialize(MCContext &Ctx,
                                          const TargetMachine &TM) {
    const ARMBaseTargetMachine &ARM_TM = static_cast<const ARMBaseTargetMachine &>(TM);
    bool isAAPCS_ABI = ARM_TM.TargetABI == ARMBaseTargetMachine::ARMABI::ARM_ABI_AAPCS;
    bool genExecuteOnly =
        ARM_TM.getMCSubtargetInfo()->hasFeature(ARM::FeatureExecuteOnly);
  
    TargetLoweringObjectFileELF::Initialize(Ctx, TM);
    InitializeELF(isAAPCS_ABI);
  
    if (isAAPCS_ABI) {
      LSDASection = nullptr;
    }
  
    // Make code section unreadable when in execute-only mode
    if (genExecuteOnly) {
      unsigned Type = ELF::SHT_PROGBITS;
      unsigned Flags =
          ELF::SHF_EXECINSTR | ELF::SHF_ALLOC | ELF::SHF_ARM_PURECODE;
      // Since we cannot modify flags for an existing section, we create a new
      // section with the right flags, and use 0 as the unique ID for
      // execute-only text
      TextSection =
          Ctx.getELFSection(".text", Type, Flags, 0, "", false, 0U, nullptr);
    }
  }
  
  MCRegister ARMElfTargetObjectFile::getStaticBase() const { return ARM::R9; }
  
  const MCExpr *ARMElfTargetObjectFile::
  getIndirectSymViaRWPI(const MCSymbol *Sym) const {
    return MCSymbolRefExpr::create(Sym, MCSymbolRefExpr::VK_ARM_SBREL,
                                   getContext());
  }
  
  const MCExpr *ARMElfTargetObjectFile::getTTypeGlobalReference(
      const GlobalValue *GV, unsigned Encoding, const TargetMachine &TM,
      MachineModuleInfo *MMI, MCStreamer &Streamer) const {
    if (TM.getMCAsmInfo()->getExceptionHandlingType() != ExceptionHandling::ARM)
      return TargetLoweringObjectFileELF::getTTypeGlobalReference(
          GV, Encoding, TM, MMI, Streamer);
  
    assert(Encoding == DW_EH_PE_absptr && "Can handle absptr encoding only");
  
    return MCSymbolRefExpr::create(TM.getSymbol(GV),
                                   MCSymbolRefExpr::VK_ARM_TARGET2, getContext());
  }
  
  const MCExpr *ARMElfTargetObjectFile::
  getDebugThreadLocalSymbol(const MCSymbol *Sym) const {
    return MCSymbolRefExpr::create(Sym, MCSymbolRefExpr::VK_ARM_TLSLDO,
                                   getContext());
  }
  
  static bool isExecuteOnlyFunction(const GlobalObject *GO, SectionKind SK,
                                    const TargetMachine &TM) {
    if (const Function *F = dyn_cast<Function>(GO))
      if (TM.getSubtarget<ARMSubtarget>(*F).genExecuteOnly() && SK.isText())
        return true;
    return false;
  }
  
  MCSection *ARMElfTargetObjectFile::getExplicitSectionGlobal(
      const GlobalObject *GO, SectionKind SK, const TargetMachine &TM) const {
    // Set execute-only access for the explicit section
    if (isExecuteOnlyFunction(GO, SK, TM))
      SK = SectionKind::getExecuteOnly();
  
    return TargetLoweringObjectFileELF::getExplicitSectionGlobal(GO, SK, TM);
  }
  
  MCSection *ARMElfTargetObjectFile::SelectSectionForGlobal(
      const GlobalObject *GO, SectionKind SK, const TargetMachine &TM) const {
    // Place the global in the execute-only text section
    if (isExecuteOnlyFunction(GO, SK, TM))
      SK = SectionKind::getExecuteOnly();
  
    return TargetLoweringObjectFileELF::SelectSectionForGlobal(GO, SK, TM);
  }
  