text: //===-- MCObjectFileInfo.cpp - Object File Information --------------------===//
  //
  // 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 "llvm/MC/MCObjectFileInfo.h"
  #include "llvm/ADT/StringExtras.h"
  #include "llvm/ADT/Triple.h"
  #include "llvm/BinaryFormat/COFF.h"
  #include "llvm/BinaryFormat/ELF.h"
  #include "llvm/MC/MCAsmInfo.h"
  #include "llvm/MC/MCContext.h"
  #include "llvm/MC/MCSection.h"
  #include "llvm/MC/MCSectionCOFF.h"
  #include "llvm/MC/MCSectionELF.h"
  #include "llvm/MC/MCSectionMachO.h"
  #include "llvm/MC/MCSectionWasm.h"
  #include "llvm/MC/MCSectionXCOFF.h"
  
  using namespace llvm;
  
  static bool useCompactUnwind(const Triple &T) {
    // Only on darwin.
    if (!T.isOSDarwin())
      return false;
  
    // aarch64 always has it.
    if (T.getArch() == Triple::aarch64 || T.getArch() == Triple::aarch64_32)
      return true;
  
    // armv7k always has it.
    if (T.isWatchABI())
      return true;
  
    // Use it on newer version of OS X.
    if (T.isMacOSX() && !T.isMacOSXVersionLT(10, 6))
      return true;
  
    // And the iOS simulator.
    if (T.isiOS() &&
        (T.getArch() == Triple::x86_64 || T.getArch() == Triple::x86))
      return true;
  
    return false;
  }
  
  void MCObjectFileInfo::initMachOMCObjectFileInfo(const Triple &T) {
    // MachO
    SupportsWeakOmittedEHFrame = false;
  
    EHFrameSection = Ctx->getMachOSection(
        "__TEXT", "__eh_frame",
        MachO::S_COALESCED | MachO::S_ATTR_NO_TOC |
            MachO::S_ATTR_STRIP_STATIC_SYMS | MachO::S_ATTR_LIVE_SUPPORT,
        SectionKind::getReadOnly());
  
    if (T.isOSDarwin() &&
        (T.getArch() == Triple::aarch64 || T.getArch() == Triple::aarch64_32))
      SupportsCompactUnwindWithoutEHFrame = true;
  
    if (T.isWatchABI())
      OmitDwarfIfHaveCompactUnwind = true;
  
    FDECFIEncoding = dwarf::DW_EH_PE_pcrel;
  
    // .comm doesn't support alignment before Leopard.
    if (T.isMacOSX() && T.isMacOSXVersionLT(10, 5))
      CommDirectiveSupportsAlignment = false;
  
    TextSection // .text
      = Ctx->getMachOSection("__TEXT", "__text",
                             MachO::S_ATTR_PURE_INSTRUCTIONS,
                             SectionKind::getText());
    DataSection // .data
        = Ctx->getMachOSection("__DATA", "__data", 0, SectionKind::getData());
  
    // BSSSection might not be expected initialized on msvc.
    BSSSection = nullptr;
  
    TLSDataSection // .tdata
        = Ctx->getMachOSection("__DATA", "__thread_data",
                               MachO::S_THREAD_LOCAL_REGULAR,
                               SectionKind::getData());
    TLSBSSSection // .tbss
      = Ctx->getMachOSection("__DATA", "__thread_bss",
                             MachO::S_THREAD_LOCAL_ZEROFILL,
                             SectionKind::getThreadBSS());
  
    // TODO: Verify datarel below.
    TLSTLVSection // .tlv
        = Ctx->getMachOSection("__DATA", "__thread_vars",
                               MachO::S_THREAD_LOCAL_VARIABLES,
                               SectionKind::getData());
  
    TLSThreadInitSection = Ctx->getMachOSection(
        "__DATA", "__thread_init", MachO::S_THREAD_LOCAL_INIT_FUNCTION_POINTERS,
        SectionKind::getData());
  
    CStringSection // .cstring
      = Ctx->getMachOSection("__TEXT", "__cstring",
                             MachO::S_CSTRING_LITERALS,
                             SectionKind::getMergeable1ByteCString());
    UStringSection
      = Ctx->getMachOSection("__TEXT","__ustring", 0,
                             SectionKind::getMergeable2ByteCString());
    FourByteConstantSection // .literal4
      = Ctx->getMachOSection("__TEXT", "__literal4",
                             MachO::S_4BYTE_LITERALS,
                             SectionKind::getMergeableConst4());
    EightByteConstantSection // .literal8
      = Ctx->getMachOSection("__TEXT", "__literal8",
                             MachO::S_8BYTE_LITERALS,
                             SectionKind::getMergeableConst8());
  
    SixteenByteConstantSection // .literal16
        = Ctx->getMachOSection("__TEXT", "__literal16",
                               MachO::S_16BYTE_LITERALS,
                               SectionKind::getMergeableConst16());
  
    ReadOnlySection  // .const
      = Ctx->getMachOSection("__TEXT", "__const", 0,
                             SectionKind::getReadOnly());
  
    // If the target is not powerpc, map the coal sections to the non-coal
    // sections.
    //
    // "__TEXT/__textcoal_nt" => section "__TEXT/__text"
    // "__TEXT/__const_coal"  => section "__TEXT/__const"
    // "__DATA/__datacoal_nt" => section "__DATA/__data"
    Triple::ArchType ArchTy = T.getArch();
  
    ConstDataSection  // .const_data
      = Ctx->getMachOSection("__DATA", "__const", 0,
                             SectionKind::getReadOnlyWithRel());
  
    if (ArchTy == Triple::ppc || ArchTy == Triple::ppc64) {
      TextCoalSection
        = Ctx->getMachOSection("__TEXT", "__textcoal_nt",
                               MachO::S_COALESCED |
                               MachO::S_ATTR_PURE_INSTRUCTIONS,
                               SectionKind::getText());
      ConstTextCoalSection
        = Ctx->getMachOSection("__TEXT", "__const_coal",
                               MachO::S_COALESCED,
                               SectionKind::getReadOnly());
      DataCoalSection = Ctx->getMachOSection(
          "__DATA", "__datacoal_nt", MachO::S_COALESCED, SectionKind::getData());
      ConstDataCoalSection = DataCoalSection;
    } else {
      TextCoalSection = TextSection;
      ConstTextCoalSection = ReadOnlySection;
      DataCoalSection = DataSection;
      ConstDataCoalSection = ConstDataSection;
    }
  
    DataCommonSection
      = Ctx->getMachOSection("__DATA","__common",
                             MachO::S_ZEROFILL,
                             SectionKind::getBSS());
    DataBSSSection
      = Ctx->getMachOSection("__DATA","__bss", MachO::S_ZEROFILL,
                             SectionKind::getBSS());
  
  
    LazySymbolPointerSection
      = Ctx->getMachOSection("__DATA", "__la_symbol_ptr",
                             MachO::S_LAZY_SYMBOL_POINTERS,
                             SectionKind::getMetadata());
    NonLazySymbolPointerSection
      = Ctx->getMachOSection("__DATA", "__nl_symbol_ptr",
                             MachO::S_NON_LAZY_SYMBOL_POINTERS,
                             SectionKind::getMetadata());
  
    ThreadLocalPointerSection
      = Ctx->getMachOSection("__DATA", "__thread_ptr",
                             MachO::S_THREAD_LOCAL_VARIABLE_POINTERS,
                             SectionKind::getMetadata());
  
    // Exception Handling.
    LSDASection = Ctx->getMachOSection("__TEXT", "__gcc_except_tab", 0,
                                       SectionKind::getReadOnlyWithRel());
  
    COFFDebugSymbolsSection = nullptr;
    COFFDebugTypesSection = nullptr;
    COFFGlobalTypeHashesSection = nullptr;
  
    if (useCompactUnwind(T)) {
      CompactUnwindSection =
          Ctx->getMachOSection("__LD", "__compact_unwind", MachO::S_ATTR_DEBUG,
                               SectionKind::getReadOnly());
  
      if (T.getArch() == Triple::x86_64 || T.getArch() == Triple::x86)
        CompactUnwindDwarfEHFrameOnly = 0x04000000;  // UNWIND_X86_64_MODE_DWARF
      else if (T.getArch() == Triple::aarch64 || T.getArch() == Triple::aarch64_32)
        CompactUnwindDwarfEHFrameOnly = 0x03000000;  // UNWIND_ARM64_MODE_DWARF
      else if (T.getArch() == Triple::arm || T.getArch() == Triple::thumb)
        CompactUnwindDwarfEHFrameOnly = 0x04000000;  // UNWIND_ARM_MODE_DWARF
    }
  
    // Debug Information.
    DwarfDebugNamesSection =
        Ctx->getMachOSection("__DWARF", "__debug_names", MachO::S_ATTR_DEBUG,
                             SectionKind::getMetadata(), "debug_names_begin");
    DwarfAccelNamesSection =
        Ctx->getMachOSection("__DWARF", "__apple_names", MachO::S_ATTR_DEBUG,
                             SectionKind::getMetadata(), "names_begin");
    DwarfAccelObjCSection =
        Ctx->getMachOSection("__DWARF", "__apple_objc", MachO::S_ATTR_DEBUG,
                             SectionKind::getMetadata(), "objc_begin");
    // 16 character section limit...
    DwarfAccelNamespaceSection =
        Ctx->getMachOSection("__DWARF", "__apple_namespac", MachO::S_ATTR_DEBUG,
                             SectionKind::getMetadata(), "namespac_begin");
    DwarfAccelTypesSection =
        Ctx->getMachOSection("__DWARF", "__apple_types", MachO::S_ATTR_DEBUG,
                             SectionKind::getMetadata(), "types_begin");
  
    DwarfSwiftASTSection =
        Ctx->getMachOSection("__DWARF", "__swift_ast", MachO::S_ATTR_DEBUG,
                             SectionKind::getMetadata());
  
    DwarfAbbrevSection =
        Ctx->getMachOSection("__DWARF", "__debug_abbrev", MachO::S_ATTR_DEBUG,
                             SectionKind::getMetadata(), "section_abbrev");
    DwarfInfoSection =
        Ctx->getMachOSection("__DWARF", "__debug_info", MachO::S_ATTR_DEBUG,
                             SectionKind::getMetadata(), "section_info");
    DwarfLineSection =
        Ctx->getMachOSection("__DWARF", "__debug_line", MachO::S_ATTR_DEBUG,
                             SectionKind::getMetadata(), "section_line");
    DwarfLineStrSection =
        Ctx->getMachOSection("__DWARF", "__debug_line_str", MachO::S_ATTR_DEBUG,
                             SectionKind::getMetadata(), "section_line_str");
    DwarfFrameSection =
        Ctx->getMachOSection("__DWARF", "__debug_frame", MachO::S_ATTR_DEBUG,
                             SectionKind::getMetadata());
    DwarfPubNamesSection =
        Ctx->getMachOSection("__DWARF", "__debug_pubnames", MachO::S_ATTR_DEBUG,
                             SectionKind::getMetadata());
    DwarfPubTypesSection =
        Ctx->getMachOSection("__DWARF", "__debug_pubtypes", MachO::S_ATTR_DEBUG,
                             SectionKind::getMetadata());
    DwarfGnuPubNamesSection =
        Ctx->getMachOSection("__DWARF", "__debug_gnu_pubn", MachO::S_ATTR_DEBUG,
                             SectionKind::getMetadata());
    DwarfGnuPubTypesSection =
        Ctx->getMachOSection("__DWARF", "__debug_gnu_pubt", MachO::S_ATTR_DEBUG,
                             SectionKind::getMetadata());
    DwarfStrSection =
        Ctx->getMachOSection("__DWARF", "__debug_str", MachO::S_ATTR_DEBUG,
                             SectionKind::getMetadata(), "info_string");
    DwarfStrOffSection =
        Ctx->getMachOSection("__DWARF", "__debug_str_offs", MachO::S_ATTR_DEBUG,
                             SectionKind::getMetadata(), "section_str_off");
    DwarfAddrSection =
        Ctx->getMachOSection("__DWARF", "__debug_addr", MachO::S_ATTR_DEBUG,
                             SectionKind::getMetadata(), "section_info");
    DwarfLocSection =
        Ctx->getMachOSection("__DWARF", "__debug_loc", MachO::S_ATTR_DEBUG,
                             SectionKind::getMetadata(), "section_debug_loc");
    DwarfLoclistsSection =
        Ctx->getMachOSection("__DWARF", "__debug_loclists", MachO::S_ATTR_DEBUG,
                             SectionKind::getMetadata(), "section_debug_loc");
  
    DwarfARangesSection =
        Ctx->getMachOSection("__DWARF", "__debug_aranges", MachO::S_ATTR_DEBUG,
                             SectionKind::getMetadata());
    DwarfRangesSection =
        Ctx->getMachOSection("__DWARF", "__debug_ranges", MachO::S_ATTR_DEBUG,
                             SectionKind::getMetadata(), "debug_range");
    DwarfRnglistsSection =
        Ctx->getMachOSection("__DWARF", "__debug_rnglists", MachO::S_ATTR_DEBUG,
                             SectionKind::getMetadata(), "debug_range");
    DwarfMacinfoSection =
        Ctx->getMachOSection("__DWARF", "__debug_macinfo", MachO::S_ATTR_DEBUG,
                             SectionKind::getMetadata(), "debug_macinfo");
    DwarfDebugInlineSection =
        Ctx->getMachOSection("__DWARF", "__debug_inlined", MachO::S_ATTR_DEBUG,
                             SectionKind::getMetadata());
    DwarfCUIndexSection =
        Ctx->getMachOSection("__DWARF", "__debug_cu_index", MachO::S_ATTR_DEBUG,
                             SectionKind::getMetadata());
    DwarfTUIndexSection =
        Ctx->getMachOSection("__DWARF", "__debug_tu_index", MachO::S_ATTR_DEBUG,
                             SectionKind::getMetadata());
    StackMapSection = Ctx->getMachOSection("__LLVM_STACKMAPS", "__llvm_stackmaps",
                                           0, SectionKind::getMetadata());
  
    FaultMapSection = Ctx->getMachOSection("__LLVM_FAULTMAPS", "__llvm_faultmaps",
                                           0, SectionKind::getMetadata());
  
    RemarksSection = Ctx->getMachOSection(
        "__LLVM", "__remarks", MachO::S_ATTR_DEBUG, SectionKind::getMetadata());
  
    TLSExtraDataSection = TLSTLVSection;
  }
  
  void MCObjectFileInfo::initELFMCObjectFileInfo(const Triple &T, bool Large) {
    switch (T.getArch()) {
    case Triple::mips:
    case Triple::mipsel:
    case Triple::mips64:
    case Triple::mips64el:
      FDECFIEncoding = Ctx->getAsmInfo()->getCodePointerSize() == 4
                           ? dwarf::DW_EH_PE_sdata4
                           : dwarf::DW_EH_PE_sdata8;
      break;
    case Triple::ppc64:
    case Triple::ppc64le:
    case Triple::x86_64:
      FDECFIEncoding = dwarf::DW_EH_PE_pcrel |
                       (Large ? dwarf::DW_EH_PE_sdata8 : dwarf::DW_EH_PE_sdata4);
      break;
    case Triple::bpfel:
    case Triple::bpfeb:
      FDECFIEncoding = dwarf::DW_EH_PE_sdata8;
      break;
    case Triple::hexagon:
      FDECFIEncoding =
          PositionIndependent ? dwarf::DW_EH_PE_pcrel : dwarf::DW_EH_PE_absptr;
      break;
    default:
      FDECFIEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
      break;
    }
  
    unsigned EHSectionType = T.getArch() == Triple::x86_64
                                 ? ELF::SHT_X86_64_UNWIND
                                 : ELF::SHT_PROGBITS;
  
    // Solaris requires different flags for .eh_frame to seemingly every other
    // platform.
    unsigned EHSectionFlags = ELF::SHF_ALLOC;
    if (T.isOSSolaris() && T.getArch() != Triple::x86_64)
      EHSectionFlags |= ELF::SHF_WRITE;
  
    // ELF
    BSSSection = Ctx->getELFSection(".bss", ELF::SHT_NOBITS,
                                    ELF::SHF_WRITE | ELF::SHF_ALLOC);
  
    TextSection = Ctx->getELFSection(".text", ELF::SHT_PROGBITS,
                                     ELF::SHF_EXECINSTR | ELF::SHF_ALLOC);
  
    DataSection = Ctx->getELFSection(".data", ELF::SHT_PROGBITS,
                                     ELF::SHF_WRITE | ELF::SHF_ALLOC);
  
    ReadOnlySection =
        Ctx->getELFSection(".rodata", ELF::SHT_PROGBITS, ELF::SHF_ALLOC);
  
    TLSDataSection =
        Ctx->getELFSection(".tdata", ELF::SHT_PROGBITS,
                           ELF::SHF_ALLOC | ELF::SHF_TLS | ELF::SHF_WRITE);
  
    TLSBSSSection = Ctx->getELFSection(
        ".tbss", ELF::SHT_NOBITS, ELF::SHF_ALLOC | ELF::SHF_TLS | ELF::SHF_WRITE);
  
    DataRelROSection = Ctx->getELFSection(".data.rel.ro", ELF::SHT_PROGBITS,
                                          ELF::SHF_ALLOC | ELF::SHF_WRITE);
  
    MergeableConst4Section =
        Ctx->getELFSection(".rodata.cst4", ELF::SHT_PROGBITS,
                           ELF::SHF_ALLOC | ELF::SHF_MERGE, 4, "");
  
    MergeableConst8Section =
        Ctx->getELFSection(".rodata.cst8", ELF::SHT_PROGBITS,
                           ELF::SHF_ALLOC | ELF::SHF_MERGE, 8, "");
  
    MergeableConst16Section =
        Ctx->getELFSection(".rodata.cst16", ELF::SHT_PROGBITS,
                           ELF::SHF_ALLOC | ELF::SHF_MERGE, 16, "");
  
    MergeableConst32Section =
        Ctx->getELFSection(".rodata.cst32", ELF::SHT_PROGBITS,
                           ELF::SHF_ALLOC | ELF::SHF_MERGE, 32, "");
  
    // Exception Handling Sections.
  
    // FIXME: We're emitting LSDA info into a readonly section on ELF, even though
    // it contains relocatable pointers.  In PIC mode, this is probably a big
    // runtime hit for C++ apps.  Either the contents of the LSDA need to be
    // adjusted or this should be a data section.
    LSDASection = Ctx->getELFSection(".gcc_except_table", ELF::SHT_PROGBITS,
                                     ELF::SHF_ALLOC);
  
    COFFDebugSymbolsSection = nullptr;
    COFFDebugTypesSection = nullptr;
  
    unsigned DebugSecType = ELF::SHT_PROGBITS;
  
    // MIPS .debug_* sections should have SHT_MIPS_DWARF section type
    // to distinguish among sections contain DWARF and ECOFF debug formats.
    // Sections with ECOFF debug format are obsoleted and marked by SHT_PROGBITS.
    if (T.isMIPS())
      DebugSecType = ELF::SHT_MIPS_DWARF;
  
    // Debug Info Sections.
    DwarfAbbrevSection =
        Ctx->getELFSection(".debug_abbrev", DebugSecType, 0);
    DwarfInfoSection = Ctx->getELFSection(".debug_info", DebugSecType, 0);
    DwarfLineSection = Ctx->getELFSection(".debug_line", DebugSecType, 0);
    DwarfLineStrSection =
        Ctx->getELFSection(".debug_line_str", DebugSecType,
                           ELF::SHF_MERGE | ELF::SHF_STRINGS, 1, "");
    DwarfFrameSection = Ctx->getELFSection(".debug_frame", DebugSecType, 0);
    DwarfPubNamesSection =
        Ctx->getELFSection(".debug_pubnames", DebugSecType, 0);
    DwarfPubTypesSection =
        Ctx->getELFSection(".debug_pubtypes", DebugSecType, 0);
    DwarfGnuPubNamesSection =
        Ctx->getELFSection(".debug_gnu_pubnames", DebugSecType, 0);
    DwarfGnuPubTypesSection =
        Ctx->getELFSection(".debug_gnu_pubtypes", DebugSecType, 0);
    DwarfStrSection =
        Ctx->getELFSection(".debug_str", DebugSecType,
                           ELF::SHF_MERGE | ELF::SHF_STRINGS, 1, "");
    DwarfLocSection = Ctx->getELFSection(".debug_loc", DebugSecType, 0);
    DwarfARangesSection =
        Ctx->getELFSection(".debug_aranges", DebugSecType, 0);
    DwarfRangesSection =
        Ctx->getELFSection(".debug_ranges", DebugSecType, 0);
    DwarfMacinfoSection =
        Ctx->getELFSection(".debug_macinfo", DebugSecType, 0);
  
    // DWARF5 Experimental Debug Info
  
    // Accelerator Tables
    DwarfDebugNamesSection =
        Ctx->getELFSection(".debug_names", ELF::SHT_PROGBITS, 0);
    DwarfAccelNamesSection =
        Ctx->getELFSection(".apple_names", ELF::SHT_PROGBITS, 0);
    DwarfAccelObjCSection =
        Ctx->getELFSection(".apple_objc", ELF::SHT_PROGBITS, 0);
    DwarfAccelNamespaceSection =
        Ctx->getELFSection(".apple_namespaces", ELF::SHT_PROGBITS, 0);
    DwarfAccelTypesSection =
        Ctx->getELFSection(".apple_types", ELF::SHT_PROGBITS, 0);
  
    // String Offset and Address Sections
    DwarfStrOffSection =
        Ctx->getELFSection(".debug_str_offsets", DebugSecType, 0);
    DwarfAddrSection = Ctx->getELFSection(".debug_addr", DebugSecType, 0);
    DwarfRnglistsSection = Ctx->getELFSection(".debug_rnglists", DebugSecType, 0);
    DwarfLoclistsSection = Ctx->getELFSection(".debug_loclists", DebugSecType, 0);
  
    // Fission Sections
    DwarfInfoDWOSection =
        Ctx->getELFSection(".debug_info.dwo", DebugSecType, ELF::SHF_EXCLUDE);
    DwarfTypesDWOSection =
        Ctx->getELFSection(".debug_types.dwo", DebugSecType, ELF::SHF_EXCLUDE);
    DwarfAbbrevDWOSection =
        Ctx->getELFSection(".debug_abbrev.dwo", DebugSecType, ELF::SHF_EXCLUDE);
    DwarfStrDWOSection = Ctx->getELFSection(
        ".debug_str.dwo", DebugSecType,
        ELF::SHF_MERGE | ELF::SHF_STRINGS | ELF::SHF_EXCLUDE, 1, "");
    DwarfLineDWOSection =
        Ctx->getELFSection(".debug_line.dwo", DebugSecType, ELF::SHF_EXCLUDE);
    DwarfLocDWOSection =
        Ctx->getELFSection(".debug_loc.dwo", DebugSecType, ELF::SHF_EXCLUDE);
    DwarfStrOffDWOSection = Ctx->getELFSection(".debug_str_offsets.dwo",
                                               DebugSecType, ELF::SHF_EXCLUDE);
    DwarfRnglistsDWOSection =
        Ctx->getELFSection(".debug_rnglists.dwo", DebugSecType, ELF::SHF_EXCLUDE);
  
    // DWP Sections
    DwarfCUIndexSection =
        Ctx->getELFSection(".debug_cu_index", DebugSecType, 0);
    DwarfTUIndexSection =
        Ctx->getELFSection(".debug_tu_index", DebugSecType, 0);
  
    StackMapSection =
        Ctx->getELFSection(".llvm_stackmaps", ELF::SHT_PROGBITS, ELF::SHF_ALLOC);
  
    FaultMapSection =
        Ctx->getELFSection(".llvm_faultmaps", ELF::SHT_PROGBITS, ELF::SHF_ALLOC);
  
    EHFrameSection =
        Ctx->getELFSection(".eh_frame", EHSectionType, EHSectionFlags);
  
    StackSizesSection = Ctx->getELFSection(".stack_sizes", ELF::SHT_PROGBITS, 0);
  }
  
  void MCObjectFileInfo::initCOFFMCObjectFileInfo(const Triple &T) {
    EHFrameSection =
        Ctx->getCOFFSection(".eh_frame", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
                                             COFF::IMAGE_SCN_MEM_READ,
                            SectionKind::getData());
  
    // Set the `IMAGE_SCN_MEM_16BIT` flag when compiling for thumb mode.  This is
    // used to indicate to the linker that the text segment contains thumb instructions
    // and to set the ISA selection bit for calls accordingly.
    const bool IsThumb = T.getArch() == Triple::thumb;
  
    CommDirectiveSupportsAlignment = true;
  
    // COFF
    BSSSection = Ctx->getCOFFSection(
        ".bss", COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA |
                    COFF::IMAGE_SCN_MEM_READ | COFF::IMAGE_SCN_MEM_WRITE,
        SectionKind::getBSS());
    TextSection = Ctx->getCOFFSection(
        ".text",
        (IsThumb ? COFF::IMAGE_SCN_MEM_16BIT : (COFF::SectionCharacteristics)0) |
            COFF::IMAGE_SCN_CNT_CODE | COFF::IMAGE_SCN_MEM_EXECUTE |
            COFF::IMAGE_SCN_MEM_READ,
        SectionKind::getText());
    DataSection = Ctx->getCOFFSection(
        ".data", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ |
                     COFF::IMAGE_SCN_MEM_WRITE,
        SectionKind::getData());
    ReadOnlySection = Ctx->getCOFFSection(
        ".rdata", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ,
        SectionKind::getReadOnly());
  
    if (T.getArch() == Triple::x86_64 || T.getArch() == Triple::aarch64) {
      // On Windows 64 with SEH, the LSDA is emitted into the .xdata section
      LSDASection = nullptr;
    } else {
      LSDASection = Ctx->getCOFFSection(".gcc_except_table",
                                        COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
                                            COFF::IMAGE_SCN_MEM_READ,
                                        SectionKind::getReadOnly());
    }
  
    // Debug info.
    COFFDebugSymbolsSection =
        Ctx->getCOFFSection(".debug$S", (COFF::IMAGE_SCN_MEM_DISCARDABLE |
                                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
                                         COFF::IMAGE_SCN_MEM_READ),
                            SectionKind::getMetadata());
    COFFDebugTypesSection =
        Ctx->getCOFFSection(".debug$T", (COFF::IMAGE_SCN_MEM_DISCARDABLE |
                                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
                                         COFF::IMAGE_SCN_MEM_READ),
                            SectionKind::getMetadata());
    COFFGlobalTypeHashesSection = Ctx->getCOFFSection(
        ".debug$H",
        (COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
         COFF::IMAGE_SCN_MEM_READ),
        SectionKind::getMetadata());
  
    DwarfAbbrevSection = Ctx->getCOFFSection(
        ".debug_abbrev",
        COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
            COFF::IMAGE_SCN_MEM_READ,
        SectionKind::getMetadata(), "section_abbrev");
    DwarfInfoSection = Ctx->getCOFFSection(
        ".debug_info",
        COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
            COFF::IMAGE_SCN_MEM_READ,
        SectionKind::getMetadata(), "section_info");
    DwarfLineSection = Ctx->getCOFFSection(
        ".debug_line",
        COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
            COFF::IMAGE_SCN_MEM_READ,
        SectionKind::getMetadata(), "section_line");
    DwarfLineStrSection = Ctx->getCOFFSection(
        ".debug_line_str",
        COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
            COFF::IMAGE_SCN_MEM_READ,
        SectionKind::getMetadata(), "section_line_str");
    DwarfFrameSection = Ctx->getCOFFSection(
        ".debug_frame",
        COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
            COFF::IMAGE_SCN_MEM_READ,
        SectionKind::getMetadata());
    DwarfPubNamesSection = Ctx->getCOFFSection(
        ".debug_pubnames",
        COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
            COFF::IMAGE_SCN_MEM_READ,
        SectionKind::getMetadata());
    DwarfPubTypesSection = Ctx->getCOFFSection(
        ".debug_pubtypes",
        COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
            COFF::IMAGE_SCN_MEM_READ,
        SectionKind::getMetadata());
    DwarfGnuPubNamesSection = Ctx->getCOFFSection(
        ".debug_gnu_pubnames",
        COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
            COFF::IMAGE_SCN_MEM_READ,
        SectionKind::getMetadata());
    DwarfGnuPubTypesSection = Ctx->getCOFFSection(
        ".debug_gnu_pubtypes",
        COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
            COFF::IMAGE_SCN_MEM_READ,
        SectionKind::getMetadata());
    DwarfStrSection = Ctx->getCOFFSection(
        ".debug_str",
        COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
            COFF::IMAGE_SCN_MEM_READ,
        SectionKind::getMetadata(), "info_string");
    DwarfStrOffSection = Ctx->getCOFFSection(
        ".debug_str_offsets",
        COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
            COFF::IMAGE_SCN_MEM_READ,
        SectionKind::getMetadata(), "section_str_off");
    DwarfLocSection = Ctx->getCOFFSection(
        ".debug_loc",
        COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
            COFF::IMAGE_SCN_MEM_READ,
        SectionKind::getMetadata(), "section_debug_loc");
    DwarfARangesSection = Ctx->getCOFFSection(
        ".debug_aranges",
        COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
            COFF::IMAGE_SCN_MEM_READ,
        SectionKind::getMetadata());
    DwarfRangesSection = Ctx->getCOFFSection(
        ".debug_ranges",
        COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
            COFF::IMAGE_SCN_MEM_READ,
        SectionKind::getMetadata(), "debug_range");
    DwarfMacinfoSection = Ctx->getCOFFSection(
        ".debug_macinfo",
        COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
            COFF::IMAGE_SCN_MEM_READ,
        SectionKind::getMetadata(), "debug_macinfo");
    DwarfInfoDWOSection = Ctx->getCOFFSection(
        ".debug_info.dwo",
        COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
            COFF::IMAGE_SCN_MEM_READ,
        SectionKind::getMetadata(), "section_info_dwo");
    DwarfTypesDWOSection = Ctx->getCOFFSection(
        ".debug_types.dwo",
        COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
            COFF::IMAGE_SCN_MEM_READ,
        SectionKind::getMetadata(), "section_types_dwo");
    DwarfAbbrevDWOSection = Ctx->getCOFFSection(
        ".debug_abbrev.dwo",
        COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
            COFF::IMAGE_SCN_MEM_READ,
        SectionKind::getMetadata(), "section_abbrev_dwo");
    DwarfStrDWOSection = Ctx->getCOFFSection(
        ".debug_str.dwo",
        COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
            COFF::IMAGE_SCN_MEM_READ,
        SectionKind::getMetadata(), "skel_string");
    DwarfLineDWOSection = Ctx->getCOFFSection(
        ".debug_line.dwo",
        COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
            COFF::IMAGE_SCN_MEM_READ,
        SectionKind::getMetadata());
    DwarfLocDWOSection = Ctx->getCOFFSection(
        ".debug_loc.dwo",
        COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
            COFF::IMAGE_SCN_MEM_READ,
        SectionKind::getMetadata(), "skel_loc");
    DwarfStrOffDWOSection = Ctx->getCOFFSection(
        ".debug_str_offsets.dwo",
        COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
            COFF::IMAGE_SCN_MEM_READ,
        SectionKind::getMetadata(), "section_str_off_dwo");
    DwarfAddrSection = Ctx->getCOFFSection(
        ".debug_addr",
        COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
            COFF::IMAGE_SCN_MEM_READ,
        SectionKind::getMetadata(), "addr_sec");
    DwarfCUIndexSection = Ctx->getCOFFSection(
        ".debug_cu_index",
        COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
            COFF::IMAGE_SCN_MEM_READ,
        SectionKind::getMetadata());
    DwarfTUIndexSection = Ctx->getCOFFSection(
        ".debug_tu_index",
        COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
            COFF::IMAGE_SCN_MEM_READ,
        SectionKind::getMetadata());
    DwarfDebugNamesSection = Ctx->getCOFFSection(
        ".debug_names",
        COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
            COFF::IMAGE_SCN_MEM_READ,
        SectionKind::getMetadata(), "debug_names_begin");
    DwarfAccelNamesSection = Ctx->getCOFFSection(
        ".apple_names",
        COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
            COFF::IMAGE_SCN_MEM_READ,
        SectionKind::getMetadata(), "names_begin");
    DwarfAccelNamespaceSection = Ctx->getCOFFSection(
        ".apple_namespaces",
        COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
            COFF::IMAGE_SCN_MEM_READ,
        SectionKind::getMetadata(), "namespac_begin");
    DwarfAccelTypesSection = Ctx->getCOFFSection(
        ".apple_types",
        COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
            COFF::IMAGE_SCN_MEM_READ,
        SectionKind::getMetadata(), "types_begin");
    DwarfAccelObjCSection = Ctx->getCOFFSection(
        ".apple_objc",
        COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
            COFF::IMAGE_SCN_MEM_READ,
        SectionKind::getMetadata(), "objc_begin");
  
    DrectveSection = Ctx->getCOFFSection(
        ".drectve", COFF::IMAGE_SCN_LNK_INFO | COFF::IMAGE_SCN_LNK_REMOVE,
        SectionKind::getMetadata());
  
    PDataSection = Ctx->getCOFFSection(
        ".pdata", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ,
        SectionKind::getData());
  
    XDataSection = Ctx->getCOFFSection(
        ".xdata", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ,
        SectionKind::getData());
  
    SXDataSection = Ctx->getCOFFSection(".sxdata", COFF::IMAGE_SCN_LNK_INFO,
                                        SectionKind::getMetadata());
  
    GFIDsSection = Ctx->getCOFFSection(".gfids$y",
                                       COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
                                           COFF::IMAGE_SCN_MEM_READ,
                                       SectionKind::getMetadata());
  
    GLJMPSection = Ctx->getCOFFSection(".gljmp$y",
                                       COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
                                           COFF::IMAGE_SCN_MEM_READ,
                                       SectionKind::getMetadata());
  
    TLSDataSection = Ctx->getCOFFSection(
        ".tls$", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ |
                     COFF::IMAGE_SCN_MEM_WRITE,
        SectionKind::getData());
  
    StackMapSection = Ctx->getCOFFSection(".llvm_stackmaps",
                                          COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
                                              COFF::IMAGE_SCN_MEM_READ,
                                          SectionKind::getReadOnly());
  }
  
  void MCObjectFileInfo::initWasmMCObjectFileInfo(const Triple &T) {
    TextSection = Ctx->getWasmSection(".text", SectionKind::getText());
    DataSection = Ctx->getWasmSection(".data", SectionKind::getData());
  
    DwarfLineSection =
        Ctx->getWasmSection(".debug_line", SectionKind::getMetadata());
    DwarfLineStrSection =
        Ctx->getWasmSection(".debug_line_str", SectionKind::getMetadata());
    DwarfStrSection =
        Ctx->getWasmSection(".debug_str", SectionKind::getMetadata());
    DwarfLocSection =
        Ctx->getWasmSection(".debug_loc", SectionKind::getMetadata());
    DwarfAbbrevSection =
        Ctx->getWasmSection(".debug_abbrev", SectionKind::getMetadata());
    DwarfARangesSection = Ctx->getWasmSection(".debug_aranges", SectionKind::getMetadata());
    DwarfRangesSection =
        Ctx->getWasmSection(".debug_ranges", SectionKind::getMetadata());
    DwarfMacinfoSection =
        Ctx->getWasmSection(".debug_macinfo", SectionKind::getMetadata());
    DwarfAddrSection = Ctx->getWasmSection(".debug_addr", SectionKind::getMetadata());
    DwarfCUIndexSection = Ctx->getWasmSection(".debug_cu_index", SectionKind::getMetadata());
    DwarfTUIndexSection = Ctx->getWasmSection(".debug_tu_index", SectionKind::getMetadata());
    DwarfInfoSection =
        Ctx->getWasmSection(".debug_info", SectionKind::getMetadata());
    DwarfFrameSection = Ctx->getWasmSection(".debug_frame", SectionKind::getMetadata());
    DwarfPubNamesSection = Ctx->getWasmSection(".debug_pubnames", SectionKind::getMetadata());
    DwarfPubTypesSection = Ctx->getWasmSection(".debug_pubtypes", SectionKind::getMetadata());
  
    // Wasm use data section for LSDA.
    // TODO Consider putting each function's exception table in a separate
    // section, as in -function-sections, to facilitate lld's --gc-section.
    LSDASection = Ctx->getWasmSection(".rodata.gcc_except_table",
                                      SectionKind::getReadOnlyWithRel());
  
    // TODO: Define more sections.
  }
  
  void MCObjectFileInfo::initXCOFFMCObjectFileInfo(const Triple &T) {
    // The default csect for program code. Functions without a specified section
    // get placed into this csect. The choice of csect name is not a property of
    // the ABI or object file format. For example, the XL compiler uses an unnamed
    // csect for program code.
    TextSection = Ctx->getXCOFFSection(
        ".text", XCOFF::StorageMappingClass::XMC_PR, XCOFF::XTY_SD,
        XCOFF::C_HIDEXT, SectionKind::getText());
  
    DataSection = Ctx->getXCOFFSection(
        ".data", XCOFF::StorageMappingClass::XMC_RW, XCOFF::XTY_SD,
        XCOFF::C_HIDEXT, SectionKind::getData());
  }
  
  void MCObjectFileInfo::InitMCObjectFileInfo(const Triple &TheTriple, bool PIC,
                                              MCContext &ctx,
                                              bool LargeCodeModel) {
    PositionIndependent = PIC;
    Ctx = &ctx;
  
    // Common.
    CommDirectiveSupportsAlignment = true;
    SupportsWeakOmittedEHFrame = true;
    SupportsCompactUnwindWithoutEHFrame = false;
    OmitDwarfIfHaveCompactUnwind = false;
  
    FDECFIEncoding = dwarf::DW_EH_PE_absptr;
  
    CompactUnwindDwarfEHFrameOnly = 0;
  
    EHFrameSection = nullptr;             // Created on demand.
    CompactUnwindSection = nullptr;       // Used only by selected targets.
    DwarfAccelNamesSection = nullptr;     // Used only by selected targets.
    DwarfAccelObjCSection = nullptr;      // Used only by selected targets.
    DwarfAccelNamespaceSection = nullptr; // Used only by selected targets.
    DwarfAccelTypesSection = nullptr;     // Used only by selected targets.
  
    TT = TheTriple;
  
    switch (TT.getObjectFormat()) {
    case Triple::MachO:
      Env = IsMachO;
      initMachOMCObjectFileInfo(TT);
      break;
    case Triple::COFF:
      if (!TT.isOSWindows())
        report_fatal_error(
            "Cannot initialize MC for non-Windows COFF object files.");
  
      Env = IsCOFF;
      initCOFFMCObjectFileInfo(TT);
      break;
    case Triple::ELF:
      Env = IsELF;
      initELFMCObjectFileInfo(TT, LargeCodeModel);
      break;
    case Triple::Wasm:
      Env = IsWasm;
      initWasmMCObjectFileInfo(TT);
      break;
    case Triple::XCOFF:
      Env = IsXCOFF;
      initXCOFFMCObjectFileInfo(TT);
      break;
    case Triple::UnknownObjectFormat:
      report_fatal_error("Cannot initialize MC for unknown object file format.");
      break;
    }
  }
  
  MCSection *MCObjectFileInfo::getDwarfComdatSection(const char *Name,
                                                     uint64_t Hash) const {
    switch (TT.getObjectFormat()) {
    case Triple::ELF:
      return Ctx->getELFSection(Name, ELF::SHT_PROGBITS, ELF::SHF_GROUP, 0,
                                utostr(Hash));
    case Triple::MachO:
    case Triple::COFF:
    case Triple::Wasm:
    case Triple::XCOFF:
    case Triple::UnknownObjectFormat:
      report_fatal_error("Cannot get DWARF comdat section for this object file "
                         "format: not implemented.");
      break;
    }
    llvm_unreachable("Unknown ObjectFormatType");
  }
  
  MCSection *
  MCObjectFileInfo::getStackSizesSection(const MCSection &TextSec) const {
    if (Env != IsELF)
      return StackSizesSection;
  
    const MCSectionELF &ElfSec = static_cast<const MCSectionELF &>(TextSec);
    unsigned Flags = ELF::SHF_LINK_ORDER;
    StringRef GroupName;
    if (const MCSymbol *Group = ElfSec.getGroup()) {
      GroupName = Group->getName();
      Flags |= ELF::SHF_GROUP;
    }
  
    const MCSymbol *Link = TextSec.getBeginSymbol();
    auto It = StackSizesUniquing.insert({Link, StackSizesUniquing.size()});
    unsigned UniqueID = It.first->second;
  
    return Ctx->getELFSection(".stack_sizes", ELF::SHT_PROGBITS, Flags, 0,
                              GroupName, UniqueID, cast<MCSymbolELF>(Link));
  }
  