C++ Triple::getArch方法代码示例

Nios2MCAsmInfo::Nios2MCAsmInfo(const Triple &TheTriple) {
  if ((TheTriple.getArch() == Triple::nios2))
    IsLittleEndian = true; // the default of IsLittleEndian is true

  AlignmentIsInBytes = false;
  Data16bitsDirective = "\t.2byte\t";
  Data32bitsDirective = "\t.4byte\t";
  Data64bitsDirective = "\t.8byte\t";
  PrivateLabelPrefix = ".LC";
  CommentString = "#";
  ZeroDirective = "\t.space\t";
  GPRel32Directive = "\t.gpword\t";
  GPRel64Directive = "\t.gpdword\t";
  WeakRefDirective = "\t.weak\t";
  GlobalDirective = "\t.global\t";
  AscizDirective = "\t.string\t";
  UseAssignmentForEHBegin = true;

  SupportsDebugInformation = true;
  ExceptionsType = ExceptionHandling::DwarfCFI;
  DwarfRegNumForCFI = true;
  UsesELFSectionDirectiveForBSS = true;
}

static PPCTargetMachine::PPCABI computeTargetABI(const Triple &TT,
                                                 const TargetOptions &Options) {
  if (Options.MCOptions.getABIName().startswith("elfv1"))
    return PPCTargetMachine::PPC_ABI_ELFv1;
  else if (Options.MCOptions.getABIName().startswith("elfv2"))
    return PPCTargetMachine::PPC_ABI_ELFv2;

  assert(Options.MCOptions.getABIName().empty() &&
         "Unknown target-abi option!");

  if (!TT.isMacOSX()) {
    switch (TT.getArch()) {
    case Triple::ppc64le:
      return PPCTargetMachine::PPC_ABI_ELFv2;
    case Triple::ppc64:
      return PPCTargetMachine::PPC_ABI_ELFv1;
    default:
      // Fallthrough.
      ;
    }
  }
  return PPCTargetMachine::PPC_ABI_UNKNOWN;
}

static std::unique_ptr<TargetLoweringObjectFile> createTLOF(const Triple &TT) {
  if (TT.isOSBinFormatMachO()) {
    if (TT.getArch() == Triple::x86_64)
      return llvm::make_unique<X86_64MachoTargetObjectFile>();
    return llvm::make_unique<TargetLoweringObjectFileMachO>();
  }

  if (TT.isOSFreeBSD())
    return llvm::make_unique<X86FreeBSDTargetObjectFile>();
  if (TT.isOSLinux() || TT.isOSNaCl() || TT.isOSIAMCU())
    return llvm::make_unique<X86LinuxNaClTargetObjectFile>();
  if (TT.isOSSolaris())
    return llvm::make_unique<X86SolarisTargetObjectFile>();
  if (TT.isOSFuchsia())
    return llvm::make_unique<X86FuchsiaTargetObjectFile>();
  if (TT.isOSBinFormatELF())
    return llvm::make_unique<X86ELFTargetObjectFile>();
  if (TT.isKnownWindowsMSVCEnvironment() || TT.isWindowsCoreCLREnvironment())
    return llvm::make_unique<X86WindowsTargetObjectFile>();
  if (TT.isOSBinFormatCOFF())
    return llvm::make_unique<TargetLoweringObjectFileCOFF>();
  llvm_unreachable("unknown subtarget type");
}

X86MCAsmInfoMicrosoft::X86MCAsmInfoMicrosoft(const Triple &Triple) {
  if (Triple.getArch() == Triple::x86_64) {
    PrivateGlobalPrefix = ".L";
    PrivateLabelPrefix = ".L";
    PointerSize = 8;
    WinEHEncodingType = WinEH::EncodingType::Itanium;
  } else {
    // 32-bit X86 doesn't use CFI, so this isn't a real encoding type. It's just
    // a place holder that the Windows EHStreamer looks for to suppress CFI
    // output. In particular, usesWindowsCFI() returns false.
    WinEHEncodingType = WinEH::EncodingType::X86;
  }

  ExceptionsType = ExceptionHandling::WinEH;

  AssemblerDialect = AsmWriterFlavor;

  TextAlignFillValue = 0x90;

  AllowAtInName = true;

  UseIntegratedAssembler = true;
}

Expected<std::unique_ptr<LazyCallThroughManager>>
createLocalLazyCallThroughManager(const Triple &T, ExecutionSession &ES,
                                  JITTargetAddress ErrorHandlerAddr) {
  switch (T.getArch()) {
  default:
    return make_error<StringError>(
        std::string("No callback manager available for ") + T.str(),
        inconvertibleErrorCode());

  case Triple::aarch64:
    return LocalLazyCallThroughManager::Create<OrcAArch64>(ES,
                                                           ErrorHandlerAddr);

  case Triple::x86:
    return LocalLazyCallThroughManager::Create<OrcI386>(ES, ErrorHandlerAddr);

  case Triple::mips:
    return LocalLazyCallThroughManager::Create<OrcMips32Be>(ES,
                                                            ErrorHandlerAddr);

  case Triple::mipsel:
    return LocalLazyCallThroughManager::Create<OrcMips32Le>(ES,
                                                            ErrorHandlerAddr);

  case Triple::mips64:
  case Triple::mips64el:
    return LocalLazyCallThroughManager::Create<OrcMips64>(ES, ErrorHandlerAddr);

  case Triple::x86_64:
    if (T.getOS() == Triple::OSType::Win32)
      return LocalLazyCallThroughManager::Create<OrcX86_64_Win32>(
          ES, ErrorHandlerAddr);
    else
      return LocalLazyCallThroughManager::Create<OrcX86_64_SysV>(
          ES, ErrorHandlerAddr);
  }
}

X86ELFMCAsmInfo::X86ELFMCAsmInfo(const Triple &T) {
  AsmTransCBE = x86_asm_table;
  AssemblerDialect = AsmWriterFlavor;

  TextAlignFillValue = 0x90;

  PrivateGlobalPrefix = ".L";
  WeakRefDirective = "\t.weak\t";
  PCSymbol = ".";

  // Set up DWARF directives
  HasLEB128 = true;  // Target asm supports leb128 directives (little-endian)

  // Debug Information
  SupportsDebugInformation = true;

  // Exceptions handling
  ExceptionsType = ExceptionHandling::Dwarf;
  
  // OpenBSD has buggy support for .quad in 32-bit mode, just split into two
  // .words.
  if (T.getOS() == Triple::OpenBSD && T.getArch() == Triple::x86)
    Data64bitsDirective = 0;
}

int main(int argc, char **argv) {
  // Print a stack trace if we signal out.
  sys::PrintStackTraceOnErrorSignal();
  PrettyStackTraceProgram X(argc, argv);

  llvm_shutdown_obj Y; // Call llvm_shutdown() on exit.
  cl::ParseCommandLineOptions(argc, argv, "llvm object size dumper\n");

  ToolName = argv[0];
  if (OutputFormatShort.getNumOccurrences())
    OutputFormat = OutputFormatShort;
  if (RadixShort.getNumOccurrences())
    Radix = RadixShort;

  for (unsigned i = 0; i < ArchFlags.size(); ++i) {
    if (ArchFlags[i] == "all") {
      ArchAll = true;
    } else {
      Triple T = MachOObjectFile::getArch(ArchFlags[i]);
      if (T.getArch() == Triple::UnknownArch) {
        outs() << ToolName << ": for the -arch option: Unknown architecture "
               << "named '" << ArchFlags[i] << "'";
        return 1;
      }
    }
  }

  if (InputFilenames.size() == 0)
    InputFilenames.push_back("a.out");

  moreThanOneFile = InputFilenames.size() > 1;
  std::for_each(InputFilenames.begin(), InputFilenames.end(),
                PrintFileSectionSizes);

  return 0;
}

std::function<std::unique_ptr<IndirectStubsManager>()>
createLocalIndirectStubsManagerBuilder(const Triple &T) {
  switch (T.getArch()) {
    default:
      return [](){
        return llvm::make_unique<
                       orc::LocalIndirectStubsManager<orc::OrcGenericABI>>();
      };

    case Triple::aarch64:
      return [](){
        return llvm::make_unique<
                       orc::LocalIndirectStubsManager<orc::OrcAArch64>>();
      };

    case Triple::x86:
      return [](){
        return llvm::make_unique<
                       orc::LocalIndirectStubsManager<orc::OrcI386>>();
      };

    case Triple::x86_64:
      if (T.getOS() == Triple::OSType::Win32) {
        return [](){
          return llvm::make_unique<
                     orc::LocalIndirectStubsManager<orc::OrcX86_64_Win32>>();
        };
      } else {
        return [](){
          return llvm::make_unique<
                     orc::LocalIndirectStubsManager<orc::OrcX86_64_SysV>>();
        };
      }

  }
}

PPCELFMCAsmInfo::PPCELFMCAsmInfo(bool is64Bit, const Triple& T) {
  // FIXME: This is not always needed. For example, it is not needed in the
  // v2 abi.
  NeedsLocalForSize = true;

  if (is64Bit) {
    CodePointerSize = CalleeSaveStackSlotSize = 8;
  }
  IsLittleEndian = T.getArch() == Triple::ppc64le;

  // ".comm align is in bytes but .align is pow-2."
  AlignmentIsInBytes = false;

  CommentString = "#";

  // Uses '.section' before '.bss' directive
  UsesELFSectionDirectiveForBSS = true;  

  // Debug Information
  SupportsDebugInformation = true;

  DollarIsPC = true;

  // Set up DWARF directives
  MinInstAlignment = 4;

  // Exceptions handling
  ExceptionsType = ExceptionHandling::DwarfCFI;
    
  ZeroDirective = "\t.space\t";
  Data64bitsDirective = is64Bit ? "\t.quad\t" : nullptr;
  AssemblerDialect = 1;           // New-Style mnemonics.
  LCOMMDirectiveAlignmentType = LCOMM::ByteAlignment;

  UseIntegratedAssembler = true;
}

static Triple::ObjectFormatType getDefaultFormat(const Triple &T) {
  switch (T.getArch()) {
  default:
    break;
  case Triple::hexagon:
  case Triple::mips:
  case Triple::mipsel:
  case Triple::mips64:
  case Triple::mips64el:
  case Triple::r600:
  case Triple::amdgcn:
  case Triple::sparc:
  case Triple::sparcv9:
  case Triple::systemz:
  case Triple::xcore:
  case Triple::ppc64le:
    return Triple::ELF;

  case Triple::ppc:
  case Triple::ppc64:
    if (T.isOSDarwin())
      return Triple::MachO;
    return Triple::ELF;

  case Triple::wasm32:
  case Triple::wasm64:
    // Unknown for now, until an object format is specified.
    return Triple::UnknownObjectFormat;
  }

  if (T.isOSDarwin())
    return Triple::MachO;
  else if (T.isOSWindows())
    return Triple::COFF;
  return Triple::ELF;
}

void MCObjectFileInfo::initCOFFMCObjectFileInfo(const Triple &T) {
  EHFrameSection = Ctx->getCOFFSection(
      ".eh_frame", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
                       COFF::IMAGE_SCN_MEM_READ | COFF::IMAGE_SCN_MEM_WRITE,
      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());

  // FIXME: We're emitting LSDA info into a readonly section on COFF, 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.
  if (T.getArch() == Triple::x86_64) {
    // 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());

  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");

  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(
//.........这里部分代码省略.........

X86_64ABIInfo::X86_64ABIInfo(Triple TargetTriple, const DataLayout &DL)
    : TheDataLayout(DL) {
  assert(TargetTriple.getArch() == Triple::x86_64);
  IsWindows = TargetTriple.isOSWindows();
}

/// initialize - Initialize the set of available library functions based on the
/// specified target triple.  This should be carefully written so that a missing
/// target triple gets a sane set of defaults.
static void initialize(TargetLibraryInfoImpl &TLI, const Triple &T,
                       ArrayRef<const char *> StandardNames) {
  // Verify that the StandardNames array is in alphabetical order.
  assert(std::is_sorted(StandardNames.begin(), StandardNames.end(),
                        [](const char *LHS, const char *RHS) {
                          return strcmp(LHS, RHS) < 0;
                        }) &&
         "TargetLibraryInfoImpl function names must be sorted");

  if (T.getArch() == Triple::r600 ||
      T.getArch() == Triple::amdgcn) {
    TLI.setUnavailable(LibFunc::ldexp);
    TLI.setUnavailable(LibFunc::ldexpf);
    TLI.setUnavailable(LibFunc::ldexpl);
  }

  // There are no library implementations of mempcy and memset for AMD gpus and
  // these can be difficult to lower in the backend.
  if (T.getArch() == Triple::r600 ||
      T.getArch() == Triple::amdgcn) {
    TLI.setUnavailable(LibFunc::memcpy);
    TLI.setUnavailable(LibFunc::memset);
    TLI.setUnavailable(LibFunc::memset_pattern16);
    return;
  }

  // memset_pattern16 is only available on iOS 3.0 and Mac OS X 10.5 and later.
  // All versions of watchOS support it.
  if (T.isMacOSX()) {
    if (T.isMacOSXVersionLT(10, 5))
      TLI.setUnavailable(LibFunc::memset_pattern16);
  } else if (T.isiOS()) {
    if (T.isOSVersionLT(3, 0))
      TLI.setUnavailable(LibFunc::memset_pattern16);
  } else if (!T.isWatchOS()) {
    TLI.setUnavailable(LibFunc::memset_pattern16);
  }

  if (!hasSinCosPiStret(T)) {
    TLI.setUnavailable(LibFunc::sinpi);
    TLI.setUnavailable(LibFunc::sinpif);
    TLI.setUnavailable(LibFunc::cospi);
    TLI.setUnavailable(LibFunc::cospif);
    TLI.setUnavailable(LibFunc::sincospi_stret);
    TLI.setUnavailable(LibFunc::sincospif_stret);
  }

  if (T.isMacOSX() && T.getArch() == Triple::x86 &&
      !T.isMacOSXVersionLT(10, 7)) {
    // x86-32 OSX has a scheme where fwrite and fputs (and some other functions
    // we don't care about) have two versions; on recent OSX, the one we want
    // has a $UNIX2003 suffix. The two implementations are identical except
    // for the return value in some edge cases.  However, we don't want to
    // generate code that depends on the old symbols.
    TLI.setAvailableWithName(LibFunc::fwrite, "fwrite$UNIX2003");
    TLI.setAvailableWithName(LibFunc::fputs, "fputs$UNIX2003");
  }

  // iprintf and friends are only available on XCore and TCE.
  if (T.getArch() != Triple::xcore && T.getArch() != Triple::tce) {
    TLI.setUnavailable(LibFunc::iprintf);
    TLI.setUnavailable(LibFunc::siprintf);
    TLI.setUnavailable(LibFunc::fiprintf);
  }

  if (T.isOSWindows() && !T.isOSCygMing()) {
    // Win32 does not support long double
    TLI.setUnavailable(LibFunc::acosl);
    TLI.setUnavailable(LibFunc::asinl);
    TLI.setUnavailable(LibFunc::atanl);
    TLI.setUnavailable(LibFunc::atan2l);
    TLI.setUnavailable(LibFunc::ceill);
    TLI.setUnavailable(LibFunc::copysignl);
    TLI.setUnavailable(LibFunc::cosl);
    TLI.setUnavailable(LibFunc::coshl);
    TLI.setUnavailable(LibFunc::expl);
    TLI.setUnavailable(LibFunc::fabsf); // Win32 and Win64 both lack fabsf
    TLI.setUnavailable(LibFunc::fabsl);
    TLI.setUnavailable(LibFunc::floorl);
    TLI.setUnavailable(LibFunc::fmaxl);
    TLI.setUnavailable(LibFunc::fminl);
    TLI.setUnavailable(LibFunc::fmodl);
    TLI.setUnavailable(LibFunc::frexpl);
    TLI.setUnavailable(LibFunc::ldexpf);
    TLI.setUnavailable(LibFunc::ldexpl);
    TLI.setUnavailable(LibFunc::logl);
    TLI.setUnavailable(LibFunc::modfl);
    TLI.setUnavailable(LibFunc::powl);
    TLI.setUnavailable(LibFunc::sinl);
    TLI.setUnavailable(LibFunc::sinhl);
    TLI.setUnavailable(LibFunc::sqrtl);
    TLI.setUnavailable(LibFunc::tanl);
    TLI.setUnavailable(LibFunc::tanhl);

    // Win32 only has C89 math
    TLI.setUnavailable(LibFunc::acosh);
    TLI.setUnavailable(LibFunc::acoshf);
//.........这里部分代码省略.........

void MCObjectFileInfo::initCOFFMCObjectFileInfo(Triple T) {
  EHFrameSection = Ctx->getCOFFSection(
      ".eh_frame", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
                       COFF::IMAGE_SCN_MEM_READ | COFF::IMAGE_SCN_MEM_WRITE,
      SectionKind::getDataRel());

  bool IsWoA = T.getArch() == Triple::arm || 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",
      (IsWoA ? 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::getDataRel());
  ReadOnlySection = Ctx->getCOFFSection(
      ".rdata", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ,
      SectionKind::getReadOnly());

  if (T.isKnownWindowsMSVCEnvironment() || T.isWindowsItaniumEnvironment()) {
    StaticCtorSection =
        Ctx->getCOFFSection(".CRT$XCU", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
                                            COFF::IMAGE_SCN_MEM_READ,
                            SectionKind::getReadOnly());
    StaticDtorSection =
        Ctx->getCOFFSection(".CRT$XTX", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
                                            COFF::IMAGE_SCN_MEM_READ,
                            SectionKind::getReadOnly());
  } else {
    StaticCtorSection = Ctx->getCOFFSection(
        ".ctors", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
                      COFF::IMAGE_SCN_MEM_READ | COFF::IMAGE_SCN_MEM_WRITE,
        SectionKind::getDataRel());
    StaticDtorSection = Ctx->getCOFFSection(
        ".dtors", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
                      COFF::IMAGE_SCN_MEM_READ | COFF::IMAGE_SCN_MEM_WRITE,
        SectionKind::getDataRel());
  }

  // FIXME: We're emitting LSDA info into a readonly section on COFF, 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.
  assert(T.isOSWindows() && "Windows is the only supported COFF target");
  if (T.getArch() == Triple::x86_64) {
    // 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());

  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");

  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 |
//.........这里部分代码省略.........

static Triple::ObjectFormatType getDefaultFormat(const Triple &T) {
  switch (T.getArch()) {
  case Triple::UnknownArch:
  case Triple::aarch64:
  case Triple::arm:
  case Triple::thumb:
  case Triple::x86:
  case Triple::x86_64:
    if (T.isOSDarwin())
      return Triple::MachO;
    else if (T.isOSWindows())
      return Triple::COFF;
    return Triple::ELF;

  case Triple::aarch64_be:
  case Triple::amdgcn:
  case Triple::amdil:
  case Triple::amdil64:
  case Triple::armeb:
  case Triple::avr:
  case Triple::bpfeb:
  case Triple::bpfel:
  case Triple::hexagon:
  case Triple::lanai:
  case Triple::hsail:
  case Triple::hsail64:
  case Triple::kalimba:
  case Triple::le32:
  case Triple::le64:
  case Triple::mips:
  case Triple::mips64:
  case Triple::mips64el:
  case Triple::mipsel:
  case Triple::msp430:
  case Triple::nvptx:
  case Triple::nvptx64:
  case Triple::ppc64le:
  case Triple::r600:
  case Triple::renderscript32:
  case Triple::renderscript64:
  case Triple::shave:
  case Triple::sparc:
  case Triple::sparcel:
  case Triple::sparcv9:
  case Triple::spir:
  case Triple::spir64:
  case Triple::systemz:
  case Triple::tce:
  case Triple::thumbeb:
  case Triple::wasm32:
  case Triple::wasm64:
  case Triple::xcore:
    return Triple::ELF;

  case Triple::ppc:
  case Triple::ppc64:
    if (T.isOSDarwin())
      return Triple::MachO;
    return Triple::ELF;
  }
  llvm_unreachable("unknown architecture");
}