ToolChain.cpp

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//===- ToolChain.cpp - Collections of tools for one platform --------------===//
//
// 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 "clang/Driver/ToolChain.h"
#include "ToolChains/Arch/AArch64.h"
#include "ToolChains/Arch/AMDGPU.h"
#include "ToolChains/Arch/ARM.h"
#include "ToolChains/Arch/RISCV.h"
#include "ToolChains/Clang.h"
#include "ToolChains/Flang.h"
#include "ToolChains/InterfaceStubs.h"
#include "clang/Basic/ObjCRuntime.h"
#include "clang/Basic/Sanitizers.h"
#include "clang/Config/config.h"
#include "clang/Driver/Action.h"
#include "clang/Driver/CommonArgs.h"
#include "clang/Driver/Driver.h"
#include "clang/Driver/InputInfo.h"
#include "clang/Driver/Job.h"
#include "clang/Driver/SanitizerArgs.h"
#include "clang/Driver/XRayArgs.h"
#include "clang/Options/Options.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/Twine.h"
#include "llvm/Config/llvm-config.h"
#include "llvm/MC/MCTargetOptions.h"
#include "llvm/MC/TargetRegistry.h"
#include "llvm/Option/Arg.h"
#include "llvm/Option/ArgList.h"
#include "llvm/Option/OptTable.h"
#include "llvm/Option/Option.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/FileUtilities.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/Process.h"
#include "llvm/Support/VersionTuple.h"
#include "llvm/Support/VirtualFileSystem.h"
#include "llvm/TargetParser/AArch64TargetParser.h"
#include "llvm/TargetParser/RISCVISAInfo.h"
#include "llvm/TargetParser/TargetParser.h"
#include "llvm/TargetParser/Triple.h"
#include <cassert>
#include <cstddef>
#include <cstring>
#include <string>
 
using namespace clang;
using namespace driver;
using namespace tools;
using namespace llvm;
using namespace llvm::opt;
 
static llvm::opt::Arg *GetRTTIArgument(const ArgList &Args) {
  return Args.getLastArg(options::OPT_mkernel, options::OPT_fapple_kext,
                         options::OPT_fno_rtti, options::OPT_frtti);
}
 
static ToolChain::RTTIMode CalculateRTTIMode(const ArgList &Args,
                                             const llvm::Triple &Triple,
                                             const Arg *CachedRTTIArg) {
  // Explicit rtti/no-rtti args
  if (CachedRTTIArg) {
    if (CachedRTTIArg->getOption().matches(options::OPT_frtti))
      return ToolChain::RM_Enabled;
    else
      return ToolChain::RM_Disabled;
  }
 
  // -frtti is default, except for the PS4/PS5 and DriverKit.
  bool NoRTTI = Triple.isPS() || Triple.isDriverKit();
  return NoRTTI ? ToolChain::RM_Disabled : ToolChain::RM_Enabled;
}
 
static ToolChain::ExceptionsMode CalculateExceptionsMode(const ArgList &Args) {
  if (Args.hasFlag(options::OPT_fexceptions, options::OPT_fno_exceptions,
                   true)) {
    return ToolChain::EM_Enabled;
  }
  return ToolChain::EM_Disabled;
}
 
ToolChain::ToolChain(const Driver &D, const llvm::Triple &T,
                     const ArgList &Args)
    : D(D), Triple(T), Args(Args), CachedRTTIArg(GetRTTIArgument(Args)),
      CachedRTTIMode(CalculateRTTIMode(Args, Triple, CachedRTTIArg)),
      CachedExceptionsMode(CalculateExceptionsMode(Args)) {
  auto addIfExists = [this](path_list &List, const std::string &Path) {
    if (getVFS().exists(Path))
      List.push_back(Path);
  };
 
  if (std::optional<std::string> Path = getRuntimePath())
    getLibraryPaths().push_back(*Path);
  if (std::optional<std::string> Path = getStdlibPath())
    getFilePaths().push_back(*Path);
  for (const auto &Path : getArchSpecificLibPaths())
    addIfExists(getFilePaths(), Path);
}
 
ToolChain::OrderedMultilibs ToolChain::getOrderedMultilibs() const {
  if (!SelectedMultilibs.empty())
    return llvm::reverse(SelectedMultilibs);
 
  static const llvm::SmallVector<Multilib> Default = {Multilib()};
  return llvm::reverse(Default);
}
 
bool ToolChain::loadMultilibsFromYAML(const llvm::opt::ArgList &Args,
                                      const Driver &D, StringRef Fallback) {
  std::optional<std::string> MultilibPath =
      findMultilibsYAML(Args, D, Fallback);
  if (!MultilibPath)
    return false;
  llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> MB =
      D.getVFS().getBufferForFile(*MultilibPath);
  if (!MB)
    return false;
 
  Multilib::flags_list Flags = getMultilibFlags(Args);
  llvm::ErrorOr<MultilibSet> ErrorOrMultilibSet =
      MultilibSet::parseYaml(*MB.get());
  if (ErrorOrMultilibSet.getError())
    return false;
 
  Multilibs = std::move(ErrorOrMultilibSet.get());
 
  SmallVector<StringRef> CustomFlagMacroDefines;
  bool Result =
      Multilibs.select(D, Flags, SelectedMultilibs, &CustomFlagMacroDefines);
 
  // Custom flag macro defines are set by processCustomFlags regardless of
  // whether variant selection succeeds.
  MultilibMacroDefines.clear();
  for (StringRef Define : CustomFlagMacroDefines)
    MultilibMacroDefines.push_back(Define.str());
 
  if (!Result) {
    D.Diag(clang::diag::warn_drv_missing_multilib) << llvm::join(Flags, " ");
    SmallString<0> Data;
    raw_svector_ostream OS(Data);
    for (const Multilib &M : Multilibs)
      if (!M.isError())
        OS << "\n" << llvm::join(M.flags(), " ");
    D.Diag(clang::diag::note_drv_available_multilibs) << OS.str();
 
    for (const Multilib &M : SelectedMultilibs)
      if (M.isError())
        D.Diag(clang::diag::err_drv_multilib_custom_error)
            << M.getErrorMessage();
 
    SelectedMultilibs.clear();
    return false;
  }
 
  // Prepend variant-specific library paths. The YAML's parent directory is
  // the base for file paths; getRuntimePath() is the base for runtime paths.
  StringRef YAMLBase = llvm::sys::path::parent_path(*MultilibPath);
  std::optional<std::string> RuntimeDir = getRuntimePath();
  size_t FileInsertPos = 0;
  size_t LibInsertPos = 0;
  for (const Multilib &M : getOrderedMultilibs()) {
    if (M.isDefault())
      continue;
    SmallString<128> FilePath(YAMLBase);
    llvm::sys::path::append(FilePath, M.gccSuffix());
    getFilePaths().insert(getFilePaths().begin() + FileInsertPos,
                          std::string(FilePath));
    ++FileInsertPos;
    if (RuntimeDir) {
      SmallString<128> LibPath(*RuntimeDir);
      llvm::sys::path::append(LibPath, M.gccSuffix());
      getLibraryPaths().insert(getLibraryPaths().begin() + LibInsertPos,
                               std::string(LibPath));
      ++LibInsertPos;
    }
  }
 
  return true;
}
 
std::optional<std::string>
ToolChain::findMultilibsYAML(const llvm::opt::ArgList &Args, const Driver &D,
                             StringRef FallbackDir) {
  if (Arg *A = Args.getLastArg(options::OPT_multi_lib_config)) {
    SmallString<128> MultilibPath(A->getValue());
    if (!D.getVFS().exists(MultilibPath)) {
      D.Diag(clang::diag::err_drv_no_such_file) << MultilibPath.str();
      return std::nullopt;
    }
    return std::string(MultilibPath);
  }
 
  SmallString<128> MultilibPath;
  if (!FallbackDir.empty())
    MultilibPath = FallbackDir;
  else if (std::optional<std::string> StdlibDir = getStdlibPath())
    MultilibPath = *StdlibDir;
  else
    return std::nullopt;
  llvm::sys::path::append(MultilibPath, "multilib.yaml");
  if (!D.getVFS().exists(MultilibPath))
    return std::nullopt;
  return std::string(MultilibPath);
}
 
void ToolChain::setTripleEnvironment(llvm::Triple::EnvironmentType Env) {
  Triple.setEnvironment(Env);
  if (EffectiveTriple != llvm::Triple())
    EffectiveTriple.setEnvironment(Env);
}
 
ToolChain::~ToolChain() = default;
 
llvm::vfs::FileSystem &ToolChain::getVFS() const {
  return getDriver().getVFS();
}
 
bool ToolChain::useIntegratedAs() const {
  return Args.hasFlag(options::OPT_fintegrated_as,
                      options::OPT_fno_integrated_as,
                      IsIntegratedAssemblerDefault());
}
 
bool ToolChain::useIntegratedBackend() const {
  assert(
      ((IsIntegratedBackendDefault() && IsIntegratedBackendSupported()) ||
       (!IsIntegratedBackendDefault() || IsNonIntegratedBackendSupported())) &&
      "(Non-)integrated backend set incorrectly!");
 
  bool IBackend = Args.hasFlag(options::OPT_fintegrated_objemitter,
                               options::OPT_fno_integrated_objemitter,
                               IsIntegratedBackendDefault());
 
  // Diagnose when integrated-objemitter options are not supported by this
  // toolchain.
  unsigned DiagID;
  if ((IBackend && !IsIntegratedBackendSupported()) ||
      (!IBackend && !IsNonIntegratedBackendSupported()))
    DiagID = clang::diag::err_drv_unsupported_opt_for_target;
  else
    DiagID = clang::diag::warn_drv_unsupported_opt_for_target;
  Arg *A = Args.getLastArg(options::OPT_fno_integrated_objemitter);
  if (A && !IsNonIntegratedBackendSupported())
    D.Diag(DiagID) << A->getAsString(Args) << Triple.getTriple();
  A = Args.getLastArg(options::OPT_fintegrated_objemitter);
  if (A && !IsIntegratedBackendSupported())
    D.Diag(DiagID) << A->getAsString(Args) << Triple.getTriple();
 
  return IBackend;
}
 
bool ToolChain::useRelaxRelocations() const {
  return ENABLE_X86_RELAX_RELOCATIONS;
}
 
bool ToolChain::defaultToIEEELongDouble() const {
  return PPC_LINUX_DEFAULT_IEEELONGDOUBLE && getTriple().isOSLinux();
}
 
static void processMultilibCustomFlags(Multilib::flags_list &List,
                                       const llvm::opt::ArgList &Args) {
  for (const Arg *MultilibFlagArg :
       Args.filtered(options::OPT_fmultilib_flag)) {
    List.push_back(MultilibFlagArg->getAsString(Args));
    MultilibFlagArg->claim();
  }
}
 
static void getAArch64MultilibFlags(const Driver &D,
                                          const llvm::Triple &Triple,
                                          const llvm::opt::ArgList &Args,
                                          Multilib::flags_list &Result) {
  std::vector<StringRef> Features;
  tools::aarch64::getAArch64TargetFeatures(D, Triple, Args, Features,
                                           /*ForAS=*/false,
                                           /*ForMultilib=*/true);
  const auto UnifiedFeatures = tools::unifyTargetFeatures(Features);
  llvm::DenseSet<StringRef> FeatureSet(UnifiedFeatures.begin(),
                                       UnifiedFeatures.end());
  std::vector<std::string> MArch;
  for (const auto &Ext : AArch64::Extensions)
    if (!Ext.UserVisibleName.empty())
      if (FeatureSet.contains(Ext.PosTargetFeature))
        MArch.push_back(Ext.UserVisibleName.str());
  for (const auto &Ext : AArch64::Extensions)
    if (!Ext.UserVisibleName.empty())
      if (FeatureSet.contains(Ext.NegTargetFeature))
        MArch.push_back(("no" + Ext.UserVisibleName).str());
  StringRef ArchName;
  for (const auto &ArchInfo : AArch64::ArchInfos)
    if (FeatureSet.contains(ArchInfo->ArchFeature))
      ArchName = ArchInfo->Name;
  if (!ArchName.empty()) {
    MArch.insert(MArch.begin(), ("-march=" + ArchName).str());
    Result.push_back(llvm::join(MArch, "+"));
  }
 
  const Arg *BranchProtectionArg =
      Args.getLastArgNoClaim(options::OPT_mbranch_protection_EQ);
  if (BranchProtectionArg) {
    Result.push_back(BranchProtectionArg->getAsString(Args));
  }
 
  if (FeatureSet.contains("+strict-align"))
    Result.push_back("-mno-unaligned-access");
  else
    Result.push_back("-munaligned-access");
 
  if (Arg *Endian = Args.getLastArg(options::OPT_mbig_endian,
                                    options::OPT_mlittle_endian)) {
    if (Endian->getOption().matches(options::OPT_mbig_endian))
      Result.push_back(Endian->getAsString(Args));
  }
 
  const Arg *ABIArg = Args.getLastArgNoClaim(options::OPT_mabi_EQ);
  if (ABIArg) {
    Result.push_back(ABIArg->getAsString(Args));
  }
 
  if (const Arg *A = Args.getLastArg(options::OPT_O_Group);
      A && A->getOption().matches(options::OPT_O)) {
    switch (A->getValue()[0]) {
    case 's':
      Result.push_back("-Os");
      break;
    case 'z':
      Result.push_back("-Oz");
      break;
    }
  }
}
 
static void getARMMultilibFlags(const Driver &D, const llvm::Triple &Triple,
                                llvm::Reloc::Model RelocationModel,
                                const llvm::opt::ArgList &Args,
                                Multilib::flags_list &Result) {
  std::vector<StringRef> Features;
  llvm::ARM::FPUKind FPUKind = tools::arm::getARMTargetFeatures(
      D, Triple, Args, Features, false /*ForAs*/, true /*ForMultilib*/);
  const auto UnifiedFeatures = tools::unifyTargetFeatures(Features);
  llvm::DenseSet<StringRef> FeatureSet(UnifiedFeatures.begin(),
                                       UnifiedFeatures.end());
  std::vector<std::string> MArch;
  for (const auto &Ext : ARM::ARCHExtNames)
    if (!Ext.Name.empty())
      if (FeatureSet.contains(Ext.Feature))
        MArch.push_back(Ext.Name.str());
  for (const auto &Ext : ARM::ARCHExtNames)
    if (!Ext.Name.empty())
      if (FeatureSet.contains(Ext.NegFeature))
        MArch.push_back(("no" + Ext.Name).str());
  MArch.insert(MArch.begin(), ("-march=" + Triple.getArchName()).str());
  Result.push_back(llvm::join(MArch, "+"));
 
  switch (FPUKind) {
#define ARM_FPU(NAME, KIND, VERSION, NEON_SUPPORT, RESTRICTION)                \
  case llvm::ARM::KIND:                                                        \
    Result.push_back("-mfpu=" NAME);                                           \
    break;
#include "llvm/TargetParser/ARMTargetParser.def"
  default:
    llvm_unreachable("Invalid FPUKind");
  }
 
  switch (arm::getARMFloatABI(D, Triple, Args)) {
  case arm::FloatABI::Soft:
    Result.push_back("-mfloat-abi=soft");
    break;
  case arm::FloatABI::SoftFP:
    Result.push_back("-mfloat-abi=softfp");
    break;
  case arm::FloatABI::Hard:
    Result.push_back("-mfloat-abi=hard");
    break;
  case arm::FloatABI::Invalid:
    llvm_unreachable("Invalid float ABI");
  }
 
  if (RelocationModel == llvm::Reloc::ROPI ||
      RelocationModel == llvm::Reloc::ROPI_RWPI)
    Result.push_back("-fropi");
  else
    Result.push_back("-fno-ropi");
 
  if (RelocationModel == llvm::Reloc::RWPI ||
      RelocationModel == llvm::Reloc::ROPI_RWPI)
    Result.push_back("-frwpi");
  else
    Result.push_back("-fno-rwpi");
 
  const Arg *BranchProtectionArg =
      Args.getLastArgNoClaim(options::OPT_mbranch_protection_EQ);
  if (BranchProtectionArg) {
    Result.push_back(BranchProtectionArg->getAsString(Args));
  }
 
  if (FeatureSet.contains("+strict-align"))
    Result.push_back("-mno-unaligned-access");
  else
    Result.push_back("-munaligned-access");
 
  if (Arg *Endian = Args.getLastArg(options::OPT_mbig_endian,
                                    options::OPT_mlittle_endian)) {
    if (Endian->getOption().matches(options::OPT_mbig_endian))
      Result.push_back(Endian->getAsString(Args));
  }
 
  if (const Arg *A = Args.getLastArg(options::OPT_O_Group);
      A && A->getOption().matches(options::OPT_O)) {
    switch (A->getValue()[0]) {
    case 's':
      Result.push_back("-Os");
      break;
    case 'z':
      Result.push_back("-Oz");
      break;
    }
  }
}
 
static void getRISCVMultilibFlags(const Driver &D, const llvm::Triple &Triple,
                                  const llvm::opt::ArgList &Args,
                                  Multilib::flags_list &Result,
                                  bool hasShadowCallStack) {
  std::string Arch = riscv::getRISCVArch(Args, Triple);
  // Canonicalize arch for easier matching
  auto ISAInfo = llvm::RISCVISAInfo::parseArchString(
      Arch, /*EnableExperimentalExtensions*/ true);
  if (!llvm::errorToBool(ISAInfo.takeError()))
    Result.push_back("-march=" + (*ISAInfo)->toString());
 
  Result.push_back(("-mabi=" + riscv::getRISCVABI(Args, Triple)).str());
 
  if (hasShadowCallStack)
    Result.push_back("-fsanitize=shadow-call-stack");
  else
    Result.push_back("-fno-sanitize=shadow-call-stack");
}
 
Multilib::flags_list
ToolChain::getMultilibFlags(const llvm::opt::ArgList &Args) const {
  using namespace clang::options;
 
  std::vector<std::string> Result;
  const llvm::Triple Triple(ComputeEffectiveClangTriple(Args));
  Result.push_back("--target=" + Triple.str());
 
  // A difference of relocation model (absolutely addressed data, PIC, Arm
  // ROPI/RWPI) is likely to change whether a particular multilib variant is
  // compatible with a given link. Determine the relocation model of the
  // current link, so as to add appropriate multilib flags.
  llvm::Reloc::Model RelocationModel;
  unsigned PICLevel;
  bool IsPIE;
  {
    RegisterEffectiveTriple TripleRAII(*this, Triple);
    std::tie(RelocationModel, PICLevel, IsPIE) = ParsePICArgs(*this, Args);
  }
 
  switch (Triple.getArch()) {
  case llvm::Triple::aarch64:
  case llvm::Triple::aarch64_32:
  case llvm::Triple::aarch64_be:
    getAArch64MultilibFlags(D, Triple, Args, Result);
    break;
  case llvm::Triple::arm:
  case llvm::Triple::armeb:
  case llvm::Triple::thumb:
  case llvm::Triple::thumbeb:
    getARMMultilibFlags(D, Triple, RelocationModel, Args, Result);
    break;
  case llvm::Triple::riscv32:
  case llvm::Triple::riscv64:
  case llvm::Triple::riscv32be:
  case llvm::Triple::riscv64be:
    getRISCVMultilibFlags(D, Triple, Args, Result,
                          getSanitizerArgs(Args).hasShadowCallStack());
    break;
  default:
    break;
  }
 
  processMultilibCustomFlags(Result, Args);
 
  // Include fno-exceptions and fno-rtti
  // to improve multilib selection
  if (getRTTIMode() == ToolChain::RTTIMode::RM_Disabled)
    Result.push_back("-fno-rtti");
  else
    Result.push_back("-frtti");
 
  if (getExceptionsMode() == ToolChain::ExceptionsMode::EM_Disabled)
    Result.push_back("-fno-exceptions");
  else
    Result.push_back("-fexceptions");
 
  if (RelocationModel == llvm::Reloc::PIC_)
    Result.push_back(IsPIE ? (PICLevel > 1 ? "-fPIE" : "-fpie")
                           : (PICLevel > 1 ? "-fPIC" : "-fpic"));
  else
    Result.push_back("-fno-pic");
 
  // Sort and remove duplicates.
  std::sort(Result.begin(), Result.end());
  Result.erase(llvm::unique(Result), Result.end());
  return Result;
}
 
SanitizerArgs
ToolChain::getSanitizerArgs(const llvm::opt::ArgList &JobArgs) const {
  SanitizerArgs SanArgs(*this, JobArgs, !SanitizerArgsChecked);
  SanitizerArgsChecked = true;
  return SanArgs;
}
 
const XRayArgs ToolChain::getXRayArgs(const llvm::opt::ArgList &JobArgs) const {
  XRayArgs XRayArguments(*this, JobArgs);
  return XRayArguments;
}
 
namespace {
 
struct DriverSuffix {
  const char *Suffix;
  const char *ModeFlag;
};
 
} // namespace
 
static const DriverSuffix *FindDriverSuffix(StringRef ProgName, size_t &Pos) {
  // A list of known driver suffixes. Suffixes are compared against the
  // program name in order. If there is a match, the frontend type is updated as
  // necessary by applying the ModeFlag.
  static const DriverSuffix DriverSuffixes[] = {
      {"clang", nullptr},
      {"clang++", "--driver-mode=g++"},
      {"clang-c++", "--driver-mode=g++"},
      {"clang-cc", nullptr},
      {"clang-cpp", "--driver-mode=cpp"},
      {"clang-g++", "--driver-mode=g++"},
      {"clang-gcc", nullptr},
      {"clang-cl", "--driver-mode=cl"},
      {"cc", nullptr},
      {"cpp", "--driver-mode=cpp"},
      {"cl", "--driver-mode=cl"},
      {"++", "--driver-mode=g++"},
      {"flang", "--driver-mode=flang"},
      // For backwards compatibility, we create a symlink for `flang` called
      // `flang-new`. This will be removed in the future.
      {"flang-new", "--driver-mode=flang"},
      {"clang-dxc", "--driver-mode=dxc"},
  };
 
  for (const auto &DS : DriverSuffixes) {
    StringRef Suffix(DS.Suffix);
    if (ProgName.ends_with(Suffix)) {
      Pos = ProgName.size() - Suffix.size();
      return &DS;
    }
  }
  return nullptr;
}
 
/// Normalize the program name from argv[0] by stripping the file extension if
/// present and lower-casing the string on Windows.
static std::string normalizeProgramName(llvm::StringRef Argv0) {
  std::string ProgName = std::string(llvm::sys::path::filename(Argv0));
  if (is_style_windows(llvm::sys::path::Style::native)) {
    // Transform to lowercase for case insensitive file systems.
    std::transform(ProgName.begin(), ProgName.end(), ProgName.begin(),
                   ::tolower);
  }
  return ProgName;
}
 
static const DriverSuffix *parseDriverSuffix(StringRef ProgName, size_t &Pos) {
  // Try to infer frontend type and default target from the program name by
  // comparing it against DriverSuffixes in order.
 
  // If there is a match, the function tries to identify a target as prefix.
  // E.g. "x86_64-linux-clang" as interpreted as suffix "clang" with target
  // prefix "x86_64-linux". If such a target prefix is found, it may be
  // added via -target as implicit first argument.
  const DriverSuffix *DS = FindDriverSuffix(ProgName, Pos);
 
  if (!DS && ProgName.ends_with(".exe")) {
    // Try again after stripping the executable suffix:
    // clang++.exe -> clang++
    ProgName = ProgName.drop_back(StringRef(".exe").size());
    DS = FindDriverSuffix(ProgName, Pos);
  }
 
  if (!DS) {
    // Try again after stripping any trailing version number:
    // clang++3.5 -> clang++
    ProgName = ProgName.rtrim("0123456789.");
    DS = FindDriverSuffix(ProgName, Pos);
  }
 
  if (!DS) {
    // Try again after stripping trailing -component.
    // clang++-tot -> clang++
    ProgName = ProgName.slice(0, ProgName.rfind('-'));
    DS = FindDriverSuffix(ProgName, Pos);
  }
  return DS;
}
 
ParsedClangName
ToolChain::getTargetAndModeFromProgramName(StringRef PN) {
  std::string ProgName = normalizeProgramName(PN);
  size_t SuffixPos;
  const DriverSuffix *DS = parseDriverSuffix(ProgName, SuffixPos);
  if (!DS)
    return {};
  size_t SuffixEnd = SuffixPos + strlen(DS->Suffix);
 
  size_t LastComponent = ProgName.rfind('-', SuffixPos);
  if (LastComponent == std::string::npos)
    return ParsedClangName(ProgName.substr(0, SuffixEnd), DS->ModeFlag);
  std::string ModeSuffix = ProgName.substr(LastComponent + 1,
                                           SuffixEnd - LastComponent - 1);
 
  // Infer target from the prefix.
  StringRef Prefix(ProgName);
  Prefix = Prefix.slice(0, LastComponent);
  std::string IgnoredError;
 
  llvm::Triple Triple(Prefix);
  bool IsRegistered = llvm::TargetRegistry::lookupTarget(Triple, IgnoredError);
  return ParsedClangName{std::string(Prefix), ModeSuffix, DS->ModeFlag,
                         IsRegistered};
}
 
StringRef ToolChain::getDefaultUniversalArchName() const {
  // In universal driver terms, the arch name accepted by -arch isn't exactly
  // the same as the ones that appear in the triple. Roughly speaking, this is
  // an inverse of the darwin::getArchTypeForDarwinArchName() function.
  switch (Triple.getArch()) {
  case llvm::Triple::aarch64: {
    if (getTriple().isArm64e())
      return "arm64e";
    return "arm64";
  }
  case llvm::Triple::aarch64_32:
    return "arm64_32";
  case llvm::Triple::ppc:
    return "ppc";
  case llvm::Triple::ppcle:
    return "ppcle";
  case llvm::Triple::ppc64:
    return "ppc64";
  case llvm::Triple::ppc64le:
    return "ppc64le";
  default:
    return Triple.getArchName();
  }
}
 
std::string ToolChain::getInputFilename(const InputInfo &Input) const {
  return Input.getFilename();
}
 
ToolChain::UnwindTableLevel
ToolChain::getDefaultUnwindTableLevel(const ArgList &Args) const {
  return UnwindTableLevel::None;
}
 
Tool *ToolChain::getClang() const {
  if (!Clang)
    Clang.reset(new tools::Clang(*this, useIntegratedBackend()));
  return Clang.get();
}
 
Tool *ToolChain::getFlang() const {
  if (!Flang)
    Flang.reset(new tools::Flang(*this));
  return Flang.get();
}
 
Tool *ToolChain::buildAssembler() const {
  return new tools::ClangAs(*this);
}
 
Tool *ToolChain::buildLinker() const {
  llvm_unreachable("Linking is not supported by this toolchain");
}
 
Tool *ToolChain::buildStaticLibTool() const {
  llvm_unreachable("Creating static lib is not supported by this toolchain");
}
 
Tool *ToolChain::getAssemble() const {
  if (!Assemble)
    Assemble.reset(buildAssembler());
  return Assemble.get();
}
 
Tool *ToolChain::getClangAs() const {
  if (!Assemble)
    Assemble.reset(new tools::ClangAs(*this));
  return Assemble.get();
}
 
Tool *ToolChain::getLink() const {
  if (!Link)
    Link.reset(buildLinker());
  return Link.get();
}
 
Tool *ToolChain::getStaticLibTool() const {
  if (!StaticLibTool)
    StaticLibTool.reset(buildStaticLibTool());
  return StaticLibTool.get();
}
 
Tool *ToolChain::getIfsMerge() const {
  if (!IfsMerge)
    IfsMerge.reset(new tools::ifstool::Merger(*this));
  return IfsMerge.get();
}
 
Tool *ToolChain::getOffloadBundler() const {
  if (!OffloadBundler)
    OffloadBundler.reset(new tools::OffloadBundler(*this));
  return OffloadBundler.get();
}
 
Tool *ToolChain::getOffloadPackager() const {
  if (!OffloadPackager)
    OffloadPackager.reset(new tools::OffloadPackager(*this));
  return OffloadPackager.get();
}
 
Tool *ToolChain::getLinkerWrapper() const {
  if (!LinkerWrapper)
    LinkerWrapper.reset(new tools::LinkerWrapper(*this, getLink()));
  return LinkerWrapper.get();
}
 
Tool *ToolChain::getTool(Action::ActionClass AC) const {
  switch (AC) {
  case Action::AssembleJobClass:
    return getAssemble();
 
  case Action::IfsMergeJobClass:
    return getIfsMerge();
 
  case Action::LinkJobClass:
    return getLink();
 
  case Action::StaticLibJobClass:
    return getStaticLibTool();
 
  case Action::InputClass:
  case Action::BindArchClass:
  case Action::OffloadClass:
  case Action::LipoJobClass:
  case Action::DsymutilJobClass:
  case Action::VerifyDebugInfoJobClass:
  case Action::BinaryAnalyzeJobClass:
  case Action::BinaryTranslatorJobClass:
  case Action::ObjcopyJobClass:
    llvm_unreachable("Invalid tool kind.");
 
  case Action::CompileJobClass:
  case Action::PrecompileJobClass:
  case Action::PreprocessJobClass:
  case Action::ExtractAPIJobClass:
  case Action::AnalyzeJobClass:
  case Action::VerifyPCHJobClass:
  case Action::BackendJobClass:
    return getClang();
 
  case Action::OffloadBundlingJobClass:
  case Action::OffloadUnbundlingJobClass:
    return getOffloadBundler();
 
  case Action::OffloadPackagerJobClass:
    return getOffloadPackager();
  case Action::LinkerWrapperJobClass:
    return getLinkerWrapper();
  }
 
  llvm_unreachable("Invalid tool kind.");
}
 
static StringRef getArchNameForCompilerRTLib(const ToolChain &TC,
                                             const ArgList &Args) {
  const llvm::Triple &Triple = TC.getTriple();
  bool IsWindows = Triple.isOSWindows();
 
  if (TC.isBareMetal())
    return Triple.getArchName();
 
  if (TC.getArch() == llvm::Triple::arm || TC.getArch() == llvm::Triple::armeb)
    return (arm::getARMFloatABI(TC, Args) == arm::FloatABI::Hard && !IsWindows)
               ? "armhf"
               : "arm";
 
  // For historic reasons, Android library is using i686 instead of i386.
  if (TC.getArch() == llvm::Triple::x86 && Triple.isAndroid())
    return "i686";
 
  if (TC.getArch() == llvm::Triple::x86_64 && Triple.isX32())
    return "x32";
 
  return llvm::Triple::getArchTypeName(TC.getArch());
}
 
StringRef ToolChain::getOSLibName() const {
  if (Triple.isOSDarwin())
    return "darwin";
 
  switch (Triple.getOS()) {
  case llvm::Triple::FreeBSD:
    return "freebsd";
  case llvm::Triple::NetBSD:
    return "netbsd";
  case llvm::Triple::OpenBSD:
    return "openbsd";
  case llvm::Triple::Solaris:
    return "sunos";
  case llvm::Triple::AIX:
    return "aix";
  case llvm::Triple::Serenity:
    return "serenity";
  default:
    return getOS();
  }
}
 
std::string ToolChain::getCompilerRTPath() const {
  SmallString<128> Path(getDriver().ResourceDir);
  if (isBareMetal()) {
    llvm::sys::path::append(Path, "lib", getOSLibName());
    if (!SelectedMultilibs.empty()) {
      Path += SelectedMultilibs.back().gccSuffix();
    }
  } else if (Triple.isOSUnknown()) {
    llvm::sys::path::append(Path, "lib");
  } else {
    llvm::sys::path::append(Path, "lib", getOSLibName());
  }
  return std::string(Path);
}
 
std::string ToolChain::getCompilerRTBasename(const ArgList &Args,
                                             StringRef Component,
                                             FileType Type) const {
  std::string CRTAbsolutePath = getCompilerRT(Args, Component, Type);
  return llvm::sys::path::filename(CRTAbsolutePath).str();
}
 
std::string ToolChain::buildCompilerRTBasename(const llvm::opt::ArgList &Args,
                                               StringRef Component,
                                               FileType Type, bool AddArch,
                                               bool IsFortran) const {
  const llvm::Triple &TT = getTriple();
  bool IsITANMSVCWindows =
      TT.isWindowsMSVCEnvironment() || TT.isWindowsItaniumEnvironment();
 
  const char *Prefix =
      IsITANMSVCWindows || Type == ToolChain::FT_Object ? "" : "lib";
  const char *Suffix;
  switch (Type) {
  case ToolChain::FT_Object:
    Suffix = IsITANMSVCWindows ? ".obj" : ".o";
    break;
  case ToolChain::FT_Static:
    Suffix = IsITANMSVCWindows ? ".lib" : ".a";
    break;
  case ToolChain::FT_Shared:
    if (TT.isOSWindows())
      Suffix = TT.isOSCygMing() ? ".dll.a" : ".lib";
    else if (TT.isOSAIX())
      Suffix = ".a";
    else
      Suffix = ".so";
    break;
  }
 
  std::string ArchAndEnv;
  if (AddArch) {
    StringRef Arch = getArchNameForCompilerRTLib(*this, Args);
    const char *Env = TT.isAndroid() ? "-android" : "";
    ArchAndEnv = ("-" + Arch + Env).str();
  }
 
  std::string LibName = IsFortran ? "flang_rt." : "clang_rt.";
  return (Prefix + Twine(LibName) + Component + ArchAndEnv + Suffix).str();
}
 
std::string ToolChain::getCompilerRT(const ArgList &Args, StringRef Component,
                                     FileType Type, bool IsFortran) const {
  // Check for runtime files in the new layout without the architecture first.
  std::string CRTBasename = buildCompilerRTBasename(
      Args, Component, Type, /*AddArch=*/false, IsFortran);
  SmallString<128> Path;
  for (const auto &LibPath : getLibraryPaths()) {
    SmallString<128> P(LibPath);
    llvm::sys::path::append(P, CRTBasename);
    if (getVFS().exists(P))
      return std::string(P);
    if (Path.empty())
      Path = P;
  }
 
  // Check the filename for the old layout if the new one does not exist.
  CRTBasename = buildCompilerRTBasename(Args, Component, Type,
                                        /*AddArch=*/!IsFortran, IsFortran);
  SmallString<128> OldPath(getCompilerRTPath());
  llvm::sys::path::append(OldPath, CRTBasename);
  if (Path.empty() || getVFS().exists(OldPath))
    return std::string(OldPath);
 
  // If none is found, use a file name from the new layout, which may get
  // printed in an error message, aiding users in knowing what Clang is
  // looking for.
  return std::string(Path);
}
 
const char *ToolChain::getCompilerRTArgString(const llvm::opt::ArgList &Args,
                                              StringRef Component,
                                              FileType Type,
                                              bool isFortran) const {
  return Args.MakeArgString(getCompilerRT(Args, Component, Type, isFortran));
}
 
/// Add Fortran runtime libs
void ToolChain::addFortranRuntimeLibs(const ArgList &Args,
                                      llvm::opt::ArgStringList &CmdArgs) const {
  // Link flang_rt.runtime
  // These are handled earlier on Windows by telling the frontend driver to
  // add the correct libraries to link against as dependents in the object
  // file.
  if (!getTriple().isKnownWindowsMSVCEnvironment()) {
    StringRef F128LibName = getDriver().getFlangF128MathLibrary();
    F128LibName.consume_front_insensitive("lib");
    if (!F128LibName.empty()) {
      bool AsNeeded = !getTriple().isOSAIX();
      CmdArgs.push_back("-lflang_rt.quadmath");
      if (AsNeeded)
        addAsNeededOption(*this, Args, CmdArgs, /*as_needed=*/true);
      CmdArgs.push_back(Args.MakeArgString("-l" + F128LibName));
      if (AsNeeded)
        addAsNeededOption(*this, Args, CmdArgs, /*as_needed=*/false);
    }
    addFlangRTLibPath(Args, CmdArgs);
 
    // needs libexecinfo for backtrace functions
    if (getTriple().isOSFreeBSD() || getTriple().isOSNetBSD() ||
        getTriple().isOSOpenBSD() || getTriple().isOSDragonFly())
      CmdArgs.push_back("-lexecinfo");
  }
 
  // libomp needs libatomic for atomic operations if using libgcc
  if (Args.hasFlag(options::OPT_fopenmp, options::OPT_fopenmp_EQ,
                   options::OPT_fno_openmp, false)) {
    Driver::OpenMPRuntimeKind OMPRuntime = getDriver().getOpenMPRuntime(Args);
    ToolChain::RuntimeLibType RuntimeLib = GetRuntimeLibType(Args);
    if ((OMPRuntime == Driver::OMPRT_OMP &&
         RuntimeLib == ToolChain::RLT_Libgcc) &&
        !getTriple().isKnownWindowsMSVCEnvironment()) {
      CmdArgs.push_back("-latomic");
    }
  }
}
 
void ToolChain::addFortranRuntimeLibraryPath(const llvm::opt::ArgList &Args,
                                             ArgStringList &CmdArgs) const {
  auto AddLibSearchPathIfExists = [&](const Twine &Path) {
    // Linker may emit warnings about non-existing directories
    if (!llvm::sys::fs::is_directory(Path))
      return;
 
    if (getTriple().isKnownWindowsMSVCEnvironment())
      CmdArgs.push_back(Args.MakeArgString("-libpath:" + Path));
    else
      CmdArgs.push_back(Args.MakeArgString("-L" + Path));
  };
 
  // Search for flang_rt.* at the same location as clang_rt.* with
  // LLVM_ENABLE_PER_TARGET_RUNTIME_DIR=0. On most platforms, flang_rt is
  // located at the path returned by getRuntimePath() which is already added to
  // the library search path. This exception is for Apple-Darwin.
  AddLibSearchPathIfExists(getCompilerRTPath());
 
  // Fall back to the non-resource directory <driver-path>/../lib. We will
  // probably have to refine this in the future. In particular, on some
  // platforms, we may need to use lib64 instead of lib.
  SmallString<256> DefaultLibPath =
      llvm::sys::path::parent_path(getDriver().Dir);
  llvm::sys::path::append(DefaultLibPath, "lib");
  AddLibSearchPathIfExists(DefaultLibPath);
}
 
void ToolChain::addFlangRTLibPath(const ArgList &Args,
                                  llvm::opt::ArgStringList &CmdArgs) const {
  // Link static flang_rt.runtime.a or shared flang_rt.runtime.so.
  // On AIX, default to static flang-rt.
  if (Args.hasFlag(options::OPT_static_libflangrt,
                   options::OPT_shared_libflangrt, getTriple().isOSAIX()))
    CmdArgs.push_back(
        getCompilerRTArgString(Args, "runtime", ToolChain::FT_Static, true));
  else {
    CmdArgs.push_back("-lflang_rt.runtime");
    addArchSpecificRPath(*this, Args, CmdArgs);
  }
}
 
// Android target triples contain a target version. If we don't have libraries
// for the exact target version, we should fall back to the next newest version
// or a versionless path, if any.
std::optional<std::string>
ToolChain::getFallbackAndroidTargetPath(StringRef BaseDir) const {
  llvm::Triple TripleWithoutLevel(getTriple());
  TripleWithoutLevel.setEnvironmentName("android"); // remove any version number
  const std::string &TripleWithoutLevelStr = TripleWithoutLevel.str();
  unsigned TripleVersion = getTriple().getEnvironmentVersion().getMajor();
  unsigned BestVersion = 0;
 
  SmallString<32> TripleDir;
  bool UsingUnversionedDir = false;
  std::error_code EC;
  for (llvm::vfs::directory_iterator LI = getVFS().dir_begin(BaseDir, EC), LE;
       !EC && LI != LE; LI = LI.increment(EC)) {
    StringRef DirName = llvm::sys::path::filename(LI->path());
    StringRef DirNameSuffix = DirName;
    if (DirNameSuffix.consume_front(TripleWithoutLevelStr)) {
      if (DirNameSuffix.empty() && TripleDir.empty()) {
        TripleDir = DirName;
        UsingUnversionedDir = true;
      } else {
        unsigned Version;
        if (!DirNameSuffix.getAsInteger(10, Version) && Version > BestVersion &&
            Version < TripleVersion) {
          BestVersion = Version;
          TripleDir = DirName;
          UsingUnversionedDir = false;
        }
      }
    }
  }
 
  if (TripleDir.empty())
    return {};
 
  SmallString<128> P(BaseDir);
  llvm::sys::path::append(P, TripleDir);
  if (UsingUnversionedDir)
    D.Diag(diag::warn_android_unversioned_fallback) << P << getTripleString();
  return std::string(P);
}
 
llvm::Triple ToolChain::getTripleWithoutOSVersion() const {
  return (Triple.hasEnvironment()
              ? llvm::Triple(Triple.getArchName(), Triple.getVendorName(),
                             llvm::Triple::getOSTypeName(Triple.getOS()),
                             llvm::Triple::getEnvironmentTypeName(
                                 Triple.getEnvironment()))
              : llvm::Triple(Triple.getArchName(), Triple.getVendorName(),
                             llvm::Triple::getOSTypeName(Triple.getOS())));
}
 
std::optional<std::string>
ToolChain::getTargetSubDirPath(StringRef BaseDir) const {
  auto getPathForTriple =
      [&](const llvm::Triple &Triple) -> std::optional<std::string> {
    SmallString<128> P(BaseDir);
    llvm::sys::path::append(P, Triple.str());
    if (getVFS().exists(P))
      return std::string(P);
    return {};
  };
 
  const llvm::Triple &T = getTriple();
  if (auto Path = getPathForTriple(T))
    return *Path;
 
  if (T.isOSAIX()) {
    llvm::Triple AIXTriple;
    if (T.getEnvironment() == Triple::UnknownEnvironment) {
      // Strip unknown environment and the OS version from the triple.
      AIXTriple = llvm::Triple(T.getArchName(), T.getVendorName(),
                               llvm::Triple::getOSTypeName(T.getOS()));
    } else {
      // Strip the OS version from the triple.
      AIXTriple = getTripleWithoutOSVersion();
    }
    if (auto Path = getPathForTriple(AIXTriple))
      return *Path;
  }
 
  if (T.isOSzOS() &&
      (!T.getOSVersion().empty() || !T.getEnvironmentVersion().empty())) {
    // Build the triple without version information
    const llvm::Triple &TripleWithoutVersion = getTripleWithoutOSVersion();
    if (auto Path = getPathForTriple(TripleWithoutVersion))
      return *Path;
  }
 
  // When building with per target runtime directories, various ways of naming
  // the Arm architecture may have been normalised to simply "arm".
  // For example "armv8l" (Armv8 AArch32 little endian) is replaced with "arm".
  // Since an armv8l system can use libraries built for earlier architecture
  // versions assuming endian and float ABI match.
  //
  // Original triple: armv8l-unknown-linux-gnueabihf
  //  Runtime triple: arm-unknown-linux-gnueabihf
  //
  // We do not do this for armeb (big endian) because doing so could make us
  // select little endian libraries. In addition, all known armeb triples only
  // use the "armeb" architecture name.
  //
  // M profile Arm is bare metal and we know they will not be using the per
  // target runtime directory layout.
  if (T.getArch() == Triple::arm && !T.isArmMClass()) {
    llvm::Triple ArmTriple = T;
    ArmTriple.setArch(Triple::arm);
    if (auto Path = getPathForTriple(ArmTriple))
      return *Path;
  }
 
  if (T.isAndroid())
    return getFallbackAndroidTargetPath(BaseDir);
 
  return {};
}
 
std::optional<std::string> ToolChain::getRuntimePath() const {
  SmallString<128> P(D.ResourceDir);
  llvm::sys::path::append(P, "lib");
  if (auto Ret = getTargetSubDirPath(P))
    return Ret;
  // Darwin does not use per-target runtime directory.
  if (Triple.isOSDarwin())
    return {};
 
  llvm::sys::path::append(P, Triple.str());
  return std::string(P);
}
 
std::optional<std::string> ToolChain::getStdlibPath() const {
  SmallString<128> P(D.Dir);
  llvm::sys::path::append(P, "..", "lib");
  return getTargetSubDirPath(P);
}
 
std::optional<std::string> ToolChain::getStdlibIncludePath() const {
  SmallString<128> P(D.Dir);
  llvm::sys::path::append(P, "..", "include");
  return getTargetSubDirPath(P);
}
 
ToolChain::path_list ToolChain::getArchSpecificLibPaths() const {
  path_list Paths;
 
  auto AddPath = [&](const ArrayRef<StringRef> &SS) {
    SmallString<128> Path(getDriver().ResourceDir);
    llvm::sys::path::append(Path, "lib");
    for (auto &S : SS)
      llvm::sys::path::append(Path, S);
    Paths.push_back(std::string(Path));
  };
 
  AddPath({getTriple().str()});
  AddPath({getOSLibName(), llvm::Triple::getArchTypeName(getArch())});
  return Paths;
}
 
bool ToolChain::needsProfileRT(const ArgList &Args) {
  if (Args.hasArg(options::OPT_noprofilelib))
    return false;
 
  return Args.hasArg(options::OPT_fprofile_generate) ||
         Args.hasArg(options::OPT_fprofile_generate_EQ) ||
         Args.hasArg(options::OPT_fcs_profile_generate) ||
         Args.hasArg(options::OPT_fcs_profile_generate_EQ) ||
         Args.hasArg(options::OPT_fprofile_instr_generate) ||
         Args.hasArg(options::OPT_fprofile_instr_generate_EQ) ||
         Args.hasArg(options::OPT_fcreate_profile) ||
         Args.hasArg(options::OPT_fprofile_generate_cold_function_coverage) ||
         Args.hasArg(options::OPT_fprofile_generate_cold_function_coverage_EQ);
}
 
bool ToolChain::needsGCovInstrumentation(const llvm::opt::ArgList &Args) {
  return Args.hasArg(options::OPT_coverage) ||
         Args.hasFlag(options::OPT_fprofile_arcs, options::OPT_fno_profile_arcs,
                      false);
}
 
Tool *ToolChain::SelectTool(const JobAction &JA) const {
  if (D.IsFlangMode() && getDriver().ShouldUseFlangCompiler(JA)) return getFlang();
  if (getDriver().ShouldUseClangCompiler(JA)) return getClang();
  Action::ActionClass AC = JA.getKind();
  if (AC == Action::AssembleJobClass && useIntegratedAs() &&
      !getTriple().isOSAIX())
    return getClangAs();
  return getTool(AC);
}
 
std::string ToolChain::GetFilePath(const char *Name) const {
  return D.GetFilePath(Name, *this);
}
 
std::string ToolChain::GetProgramPath(const char *Name) const {
  return D.GetProgramPath(Name, *this);
}
 
std::string ToolChain::GetLinkerPath(bool *LinkerIsLLD) const {
  if (LinkerIsLLD)
    *LinkerIsLLD = false;
 
  // Get -fuse-ld= first to prevent -Wunused-command-line-argument. -fuse-ld= is
  // considered as the linker flavor, e.g. "bfd", "gold", or "lld".
  const Arg* A = Args.getLastArg(options::OPT_fuse_ld_EQ);
  StringRef UseLinker = A ? A->getValue() : getDriver().getPreferredLinker();
 
  // --ld-path= takes precedence over -fuse-ld= and specifies the executable
  // name. -B, COMPILER_PATH and PATH and consulted if the value does not
  // contain a path component separator.
  // -fuse-ld=lld can be used with --ld-path= to inform clang that the binary
  // that --ld-path= points to is lld.
  if (const Arg *A = Args.getLastArg(options::OPT_ld_path_EQ)) {
    std::string Path(A->getValue());
    if (!Path.empty()) {
      if (llvm::sys::path::parent_path(Path).empty())
        Path = GetProgramPath(A->getValue());
      if (llvm::sys::fs::can_execute(Path)) {
        if (LinkerIsLLD)
          *LinkerIsLLD = UseLinker == "lld";
        return std::string(Path);
      }
    }
    getDriver().Diag(diag::err_drv_invalid_linker_name) << A->getAsString(Args);
    return GetProgramPath(getDefaultLinker());
  }
  // If we're passed -fuse-ld= with no argument, or with the argument ld,
  // then use whatever the default system linker is.
  if (UseLinker.empty() || UseLinker == "ld") {
    const char *DefaultLinker = getDefaultLinker();
    if (llvm::sys::path::is_absolute(DefaultLinker))
      return std::string(DefaultLinker);
    else
      return GetProgramPath(DefaultLinker);
  }
 
  // Extending -fuse-ld= to an absolute or relative path is unexpected. Checking
  // for the linker flavor is brittle. In addition, prepending "ld." or "ld64."
  // to a relative path is surprising. This is more complex due to priorities
  // among -B, COMPILER_PATH and PATH. --ld-path= should be used instead.
  if (UseLinker.contains('/'))
    getDriver().Diag(diag::warn_drv_fuse_ld_path);
 
  if (llvm::sys::path::is_absolute(UseLinker)) {
    // If we're passed what looks like an absolute path, don't attempt to
    // second-guess that.
    if (llvm::sys::fs::can_execute(UseLinker))
      return std::string(UseLinker);
  } else {
    llvm::SmallString<8> LinkerName;
    if (Triple.isOSDarwin())
      LinkerName.append("ld64.");
    else
      LinkerName.append("ld.");
    LinkerName.append(UseLinker);
 
    std::string LinkerPath(GetProgramPath(LinkerName.c_str()));
    if (llvm::sys::fs::can_execute(LinkerPath)) {
      if (LinkerIsLLD)
        *LinkerIsLLD = UseLinker == "lld";
      return LinkerPath;
    }
  }
 
  if (A)
    getDriver().Diag(diag::err_drv_invalid_linker_name) << A->getAsString(Args);
 
  return GetProgramPath(getDefaultLinker());
}
 
std::string ToolChain::GetStaticLibToolPath() const {
  // TODO: Add support for static lib archiving on Windows
  if (Triple.isOSDarwin())
    return GetProgramPath("libtool");
  return GetProgramPath("llvm-ar");
}
 
types::ID ToolChain::LookupTypeForExtension(StringRef Ext) const {
  types::ID id = types::lookupTypeForExtension(Ext);
 
  // Flang always runs the preprocessor and has no notion of "preprocessed
  // fortran". Here, TY_PP_Fortran is coerced to TY_Fortran to avoid treating
  // them differently.
  if (D.IsFlangMode() && id == types::TY_PP_Fortran)
    id = types::TY_Fortran;
 
  return id;
}
 
bool ToolChain::HasNativeLLVMSupport() const {
  return false;
}
 
bool ToolChain::isCrossCompiling() const {
  llvm::Triple HostTriple(LLVM_HOST_TRIPLE);
  switch (HostTriple.getArch()) {
  // The A32/T32/T16 instruction sets are not separate architectures in this
  // context.
  case llvm::Triple::arm:
  case llvm::Triple::armeb:
  case llvm::Triple::thumb:
  case llvm::Triple::thumbeb:
    return getArch() != llvm::Triple::arm && getArch() != llvm::Triple::thumb &&
           getArch() != llvm::Triple::armeb && getArch() != llvm::Triple::thumbeb;
  default:
    return HostTriple.getArch() != getArch();
  }
}
 
ObjCRuntime ToolChain::getDefaultObjCRuntime(bool isNonFragile) const {
  return ObjCRuntime(isNonFragile ? ObjCRuntime::GNUstep : ObjCRuntime::GCC,
                     VersionTuple());
}
 
llvm::ExceptionHandling
ToolChain::GetExceptionModel(const llvm::opt::ArgList &Args) const {
  return llvm::ExceptionHandling::None;
}
 
bool ToolChain::isThreadModelSupported(const StringRef Model) const {
  if (Model == "single") {
    // FIXME: 'single' is only supported on ARM and WebAssembly so far.
    return Triple.getArch() == llvm::Triple::arm ||
           Triple.getArch() == llvm::Triple::armeb ||
           Triple.getArch() == llvm::Triple::thumb ||
           Triple.getArch() == llvm::Triple::thumbeb || Triple.isWasm();
  } else if (Model == "posix")
    return true;
 
  return false;
}
 
std::string ToolChain::ComputeLLVMTriple(const ArgList &Args,
                                         StringRef BoundArch,
                                         types::ID InputType) const {
  switch (getTriple().getArch()) {
  default:
    return getTripleString().str();
 
  case llvm::Triple::x86_64: {
    llvm::Triple Triple = getTriple();
    if (!Triple.isOSBinFormatMachO())
      return getTripleString().str();
 
    if (Arg *A = Args.getLastArg(options::OPT_march_EQ)) {
      // x86_64h goes in the triple. Other -march options just use the
      // vanilla triple we already have.
      StringRef MArch = A->getValue();
      if (MArch == "x86_64h")
        Triple.setArchName(MArch);
    }
    return Triple.getTriple();
  }
  case llvm::Triple::aarch64: {
    llvm::Triple Triple = getTriple();
    if (!Triple.isOSBinFormatMachO())
      return Triple.getTriple();
 
    if (Triple.isArm64e())
      return Triple.getTriple();
 
    // FIXME: older versions of ld64 expect the "arm64" component in the actual
    // triple string and query it to determine whether an LTO file can be
    // handled. Remove this when we don't care any more.
    Triple.setArchName("arm64");
    return Triple.getTriple();
  }
  case llvm::Triple::aarch64_32:
    return getTripleString().str();
  case llvm::Triple::amdgcn: {
    llvm::Triple Triple = getTriple();
    tools::AMDGPU::setArchNameInTriple(getDriver(), Args, InputType, Triple);
    return Triple.getTriple();
  }
  case llvm::Triple::arm:
  case llvm::Triple::armeb:
  case llvm::Triple::thumb:
  case llvm::Triple::thumbeb: {
    llvm::Triple Triple = getTriple();
    tools::arm::setArchNameInTriple(getDriver(), Args, InputType, Triple);
    tools::arm::setFloatABIInTriple(getDriver(), Args, Triple);
    return Triple.getTriple();
  }
  }
}
 
std::string ToolChain::ComputeEffectiveClangTriple(const ArgList &Args,
                                                   StringRef BoundArch,
                                                   types::ID InputType) const {
  return ComputeLLVMTriple(Args, BoundArch, InputType);
}
 
std::string ToolChain::computeSysRoot() const {
  return D.SysRoot;
}
 
void ToolChain::AddClangSystemIncludeArgs(const ArgList &DriverArgs,
                                          ArgStringList &CC1Args) const {
  // Each toolchain should provide the appropriate include flags.
}
 
void ToolChain::addClangTargetOptions(
    const ArgList &DriverArgs, ArgStringList &CC1Args,
    Action::OffloadKind DeviceOffloadKind) const {}
 
void ToolChain::addClangCC1ASTargetOptions(const ArgList &Args,
                                           ArgStringList &CC1ASArgs) const {}
 
void ToolChain::addClangWarningOptions(ArgStringList &CC1Args) const {}
 
void ToolChain::addProfileRTLibs(const llvm::opt::ArgList &Args,
                                 llvm::opt::ArgStringList &CmdArgs) const {
  if (!needsProfileRT(Args) && !needsGCovInstrumentation(Args))
    return;
 
  CmdArgs.push_back(getCompilerRTArgString(Args, "profile"));
}
 
ToolChain::RuntimeLibType ToolChain::GetRuntimeLibType(
    const ArgList &Args) const {
  if (runtimeLibType)
    return *runtimeLibType;
 
  const Arg* A = Args.getLastArg(options::OPT_rtlib_EQ);
  StringRef LibName = A ? A->getValue() : CLANG_DEFAULT_RTLIB;
 
  // Only use "platform" in tests to override CLANG_DEFAULT_RTLIB!
  if (LibName == "compiler-rt")
    runtimeLibType = ToolChain::RLT_CompilerRT;
  else if (LibName == "libgcc")
    runtimeLibType = ToolChain::RLT_Libgcc;
  else if (LibName == "platform")
    runtimeLibType = GetDefaultRuntimeLibType();
  else {
    if (A)
      getDriver().Diag(diag::err_drv_invalid_rtlib_name)
          << A->getAsString(Args);
 
    runtimeLibType = GetDefaultRuntimeLibType();
  }
 
  return *runtimeLibType;
}
 
ToolChain::UnwindLibType ToolChain::GetUnwindLibType(
    const ArgList &Args) const {
  if (unwindLibType)
    return *unwindLibType;
 
  const Arg *A = Args.getLastArg(options::OPT_unwindlib_EQ);
  StringRef LibName = A ? A->getValue() : CLANG_DEFAULT_UNWINDLIB;
 
  if (LibName == "none")
    unwindLibType = ToolChain::UNW_None;
  else if (LibName == "platform" || LibName == "") {
    ToolChain::RuntimeLibType RtLibType = GetRuntimeLibType(Args);
    if (RtLibType == ToolChain::RLT_CompilerRT) {
      if (getTriple().isAndroid() || getTriple().isOSAIX() ||
          getTriple().isOSSerenity())
        unwindLibType = ToolChain::UNW_CompilerRT;
      else
        unwindLibType = ToolChain::UNW_None;
    } else if (RtLibType == ToolChain::RLT_Libgcc)
      unwindLibType = ToolChain::UNW_Libgcc;
  } else if (LibName == "libunwind") {
    if (GetRuntimeLibType(Args) == RLT_Libgcc)
      getDriver().Diag(diag::err_drv_incompatible_unwindlib);
    unwindLibType = ToolChain::UNW_CompilerRT;
  } else if (LibName == "libgcc")
    unwindLibType = ToolChain::UNW_Libgcc;
  else {
    if (A)
      getDriver().Diag(diag::err_drv_invalid_unwindlib_name)
          << A->getAsString(Args);
 
    unwindLibType = GetDefaultUnwindLibType();
  }
 
  return *unwindLibType;
}
 
ToolChain::CXXStdlibType ToolChain::GetCXXStdlibType(const ArgList &Args) const{
  if (cxxStdlibType)
    return *cxxStdlibType;
 
  const Arg *A = Args.getLastArg(options::OPT_stdlib_EQ);
  StringRef LibName = A ? A->getValue() : CLANG_DEFAULT_CXX_STDLIB;
 
  // Only use "platform" in tests to override CLANG_DEFAULT_CXX_STDLIB!
  if (LibName == "libc++")
    cxxStdlibType = ToolChain::CST_Libcxx;
  else if (LibName == "libstdc++")
    cxxStdlibType = ToolChain::CST_Libstdcxx;
  else if (LibName == "platform")
    cxxStdlibType = GetDefaultCXXStdlibType();
  else {
    if (A)
      getDriver().Diag(diag::err_drv_invalid_stdlib_name)
          << A->getAsString(Args);
 
    cxxStdlibType = GetDefaultCXXStdlibType();
  }
 
  return *cxxStdlibType;
}
 
ToolChain::CStdlibType ToolChain::GetCStdlibType(const ArgList &Args) const {
  if (cStdlibType)
    return *cStdlibType;
 
  const Arg *A = Args.getLastArg(options::OPT_cstdlib_EQ);
  StringRef LibName = A ? A->getValue() : "system";
 
  if (LibName == "newlib")
    cStdlibType = ToolChain::CST_Newlib;
  else if (LibName == "picolibc")
    cStdlibType = ToolChain::CST_Picolibc;
  else if (LibName == "llvm-libc")
    cStdlibType = ToolChain::CST_LLVMLibC;
  else if (LibName == "system")
    cStdlibType = ToolChain::CST_System;
  else {
    if (A)
      getDriver().Diag(diag::err_drv_invalid_cstdlib_name)
          << A->getAsString(Args);
    cStdlibType = ToolChain::CST_System;
  }
 
  return *cStdlibType;
}
 
/// Utility function to add a system framework directory to CC1 arguments.
void ToolChain::addSystemFrameworkInclude(const llvm::opt::ArgList &DriverArgs,
                                          llvm::opt::ArgStringList &CC1Args,
                                          const Twine &Path) {
  CC1Args.push_back("-internal-iframework");
  CC1Args.push_back(DriverArgs.MakeArgString(Path));
}
 
/// Utility function to add a system include directory with extern "C"
/// semantics to CC1 arguments.
///
/// Note that this should be used rarely, and only for directories that
/// historically and for legacy reasons are treated as having implicit extern
/// "C" semantics. These semantics are *ignored* by and large today, but its
/// important to preserve the preprocessor changes resulting from the
/// classification.
void ToolChain::addExternCSystemInclude(const ArgList &DriverArgs,
                                        ArgStringList &CC1Args,
                                        const Twine &Path) {
  CC1Args.push_back("-internal-externc-isystem");
  CC1Args.push_back(DriverArgs.MakeArgString(Path));
}
 
void ToolChain::addExternCSystemIncludeIfExists(const ArgList &DriverArgs,
                                                ArgStringList &CC1Args,
                                                const Twine &Path) {
  if (llvm::sys::fs::exists(Path))
    addExternCSystemInclude(DriverArgs, CC1Args, Path);
}
 
/// Utility function to add a system include directory to CC1 arguments.
/*static*/ void ToolChain::addSystemInclude(const ArgList &DriverArgs,
                                            ArgStringList &CC1Args,
                                            const Twine &Path) {
  CC1Args.push_back("-internal-isystem");
  CC1Args.push_back(DriverArgs.MakeArgString(Path));
}
 
/// Utility function to add a list of system framework directories to CC1.
void ToolChain::addSystemFrameworkIncludes(const ArgList &DriverArgs,
                                           ArgStringList &CC1Args,
                                           ArrayRef<StringRef> Paths) {
  for (const auto &Path : Paths) {
    CC1Args.push_back("-internal-iframework");
    CC1Args.push_back(DriverArgs.MakeArgString(Path));
  }
}
 
/// Utility function to add a list of system include directories to CC1.
void ToolChain::addSystemIncludes(const ArgList &DriverArgs,
                                  ArgStringList &CC1Args,
                                  ArrayRef<StringRef> Paths) {
  for (const auto &Path : Paths) {
    CC1Args.push_back("-internal-isystem");
    CC1Args.push_back(DriverArgs.MakeArgString(Path));
  }
}
 
std::string ToolChain::concat(StringRef Path, const Twine &A, const Twine &B,
                              const Twine &C, const Twine &D) {
  SmallString<128> Result(Path);
  llvm::sys::path::append(Result, llvm::sys::path::Style::posix, A, B, C, D);
  return std::string(Result);
}
 
std::string ToolChain::detectLibcxxVersion(StringRef IncludePath) const {
  std::error_code EC;
  int MaxVersion = 0;
  std::string MaxVersionString;
  SmallString<128> Path(IncludePath);
  llvm::sys::path::append(Path, "c++");
  for (llvm::vfs::directory_iterator LI = getVFS().dir_begin(Path, EC), LE;
       !EC && LI != LE; LI = LI.increment(EC)) {
    StringRef VersionText = llvm::sys::path::filename(LI->path());
    int Version;
    if (VersionText[0] == 'v' &&
        !VersionText.substr(1).getAsInteger(10, Version)) {
      if (Version > MaxVersion) {
        MaxVersion = Version;
        MaxVersionString = std::string(VersionText);
      }
    }
  }
  if (!MaxVersion)
    return "";
  return MaxVersionString;
}
 
void ToolChain::AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs,
                                             ArgStringList &CC1Args) const {
  // Header search paths should be handled by each of the subclasses.
  // Historically, they have not been, and instead have been handled inside of
  // the CC1-layer frontend. As the logic is hoisted out, this generic function
  // will slowly stop being called.
  //
  // While it is being called, replicate a bit of a hack to propagate the
  // '-stdlib=' flag down to CC1 so that it can in turn customize the C++
  // header search paths with it. Once all systems are overriding this
  // function, the CC1 flag and this line can be removed.
  DriverArgs.AddAllArgs(CC1Args, options::OPT_stdlib_EQ);
}
 
void ToolChain::AddClangCXXStdlibIsystemArgs(
    const llvm::opt::ArgList &DriverArgs,
    llvm::opt::ArgStringList &CC1Args) const {
  DriverArgs.ClaimAllArgs(options::OPT_stdlibxx_isystem);
  // This intentionally only looks at -nostdinc++, and not -nostdinc or
  // -nostdlibinc. The purpose of -stdlib++-isystem is to support toolchain
  // setups with non-standard search logic for the C++ headers, while still
  // allowing users of the toolchain to bring their own C++ headers. Such a
  // toolchain likely also has non-standard search logic for the C headers and
  // uses -nostdinc to suppress the default logic, but -stdlib++-isystem should
  // still work in that case and only be suppressed by an explicit -nostdinc++
  // in a project using the toolchain.
  if (!DriverArgs.hasArg(options::OPT_nostdincxx))
    for (const auto &P :
         DriverArgs.getAllArgValues(options::OPT_stdlibxx_isystem))
      addSystemInclude(DriverArgs, CC1Args, P);
}
 
bool ToolChain::ShouldLinkCXXStdlib(const llvm::opt::ArgList &Args) const {
  return getDriver().CCCIsCXX() &&
         !Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs,
                      options::OPT_nostdlibxx);
}
 
void ToolChain::AddCXXStdlibLibArgs(const ArgList &Args,
                                    ArgStringList &CmdArgs) const {
  assert(!Args.hasArg(options::OPT_nostdlibxx) &&
         "should not have called this");
  CXXStdlibType Type = GetCXXStdlibType(Args);
 
  switch (Type) {
  case ToolChain::CST_Libcxx:
    CmdArgs.push_back("-lc++");
    if (Args.hasArg(options::OPT_fexperimental_library))
      CmdArgs.push_back("-lc++experimental");
    break;
 
  case ToolChain::CST_Libstdcxx:
    CmdArgs.push_back("-lstdc++");
    break;
  }
}
 
void ToolChain::AddFilePathLibArgs(const ArgList &Args,
                                   ArgStringList &CmdArgs) const {
  for (const auto &LibPath : getFilePaths())
    if(LibPath.length() > 0)
      CmdArgs.push_back(Args.MakeArgString(StringRef("-L") + LibPath));
}
 
void ToolChain::AddCCKextLibArgs(const ArgList &Args,
                                 ArgStringList &CmdArgs) const {
  CmdArgs.push_back("-lcc_kext");
}
 
bool ToolChain::isFastMathRuntimeAvailable(const ArgList &Args,
                                           std::string &Path) const {
  // Don't implicitly link in mode-changing libraries in a shared library, since
  // this can have very deleterious effects. See the various links from
  // https://github.com/llvm/llvm-project/issues/57589 for more information.
  bool Default = !Args.hasArgNoClaim(options::OPT_shared);
 
  // Do not check for -fno-fast-math or -fno-unsafe-math when -Ofast passed
  // (to keep the linker options consistent with gcc and clang itself).
  if (Default && !isOptimizationLevelFast(Args)) {
    // Check if -ffast-math or -funsafe-math.
    Arg *A = Args.getLastArg(
        options::OPT_ffast_math, options::OPT_fno_fast_math,
        options::OPT_funsafe_math_optimizations,
        options::OPT_fno_unsafe_math_optimizations, options::OPT_ffp_model_EQ);
 
    if (!A || A->getOption().getID() == options::OPT_fno_fast_math ||
        A->getOption().getID() == options::OPT_fno_unsafe_math_optimizations)
      Default = false;
    if (A && A->getOption().getID() == options::OPT_ffp_model_EQ) {
      StringRef Model = A->getValue();
      if (Model != "fast" && Model != "aggressive")
        Default = false;
    }
  }
 
  // Whatever decision came as a result of the above implicit settings, either
  // -mdaz-ftz or -mno-daz-ftz is capable of overriding it.
  if (!Args.hasFlag(options::OPT_mdaz_ftz, options::OPT_mno_daz_ftz, Default))
    return false;
 
  // If crtfastmath.o exists add it to the arguments.
  Path = GetFilePath("crtfastmath.o");
  return (Path != "crtfastmath.o"); // Not found.
}
 
bool ToolChain::addFastMathRuntimeIfAvailable(const ArgList &Args,
                                              ArgStringList &CmdArgs) const {
  std::string Path;
  if (isFastMathRuntimeAvailable(Args, Path)) {
    CmdArgs.push_back(Args.MakeArgString(Path));
    return true;
  }
 
  return false;
}
 
Expected<SmallVector<std::string>>
ToolChain::getSystemGPUArchs(const llvm::opt::ArgList &Args) const {
  return SmallVector<std::string>();
}
 
SanitizerMask ToolChain::getSupportedSanitizers() const {
  // Return sanitizers which don't require runtime support and are not
  // platform dependent.
 
  SanitizerMask Res =
      (SanitizerKind::Undefined & ~SanitizerKind::Vptr) |
      (SanitizerKind::CFI & ~SanitizerKind::CFIICall) |
      SanitizerKind::CFICastStrict | SanitizerKind::FloatDivideByZero |
      SanitizerKind::KCFI | SanitizerKind::UnsignedIntegerOverflow |
      SanitizerKind::UnsignedShiftBase | SanitizerKind::ImplicitConversion |
      SanitizerKind::Nullability | SanitizerKind::LocalBounds |
      SanitizerKind::AllocToken;
  if (getTriple().getArch() == llvm::Triple::x86 ||
      getTriple().getArch() == llvm::Triple::x86_64 ||
      getTriple().getArch() == llvm::Triple::arm ||
      getTriple().getArch() == llvm::Triple::thumb || getTriple().isWasm() ||
      getTriple().isAArch64() || getTriple().isRISCV() ||
      getTriple().isLoongArch64() ||
      getTriple().getArch() == llvm::Triple::hexagon)
    Res |= SanitizerKind::CFIICall;
  if (getTriple().getArch() == llvm::Triple::x86_64 ||
      getTriple().isAArch64(64) || getTriple().isRISCV())
    Res |= SanitizerKind::ShadowCallStack;
  if (getTriple().isAArch64(64))
    Res |= SanitizerKind::MemTag;
  if (getTriple().isBPF())
    Res |= SanitizerKind::KernelAddress;
  return Res;
}
 
void ToolChain::AddCudaIncludeArgs(const ArgList &DriverArgs,
                                   ArgStringList &CC1Args) const {}
 
void ToolChain::AddHIPIncludeArgs(const ArgList &DriverArgs,
                                  ArgStringList &CC1Args) const {}
 
void ToolChain::addSYCLIncludeArgs(const ArgList &DriverArgs,
                                   ArgStringList &CC1Args) const {}
 
llvm::SmallVector<ToolChain::BitCodeLibraryInfo, 12>
ToolChain::getDeviceLibs(const ArgList &DriverArgs,
                         const Action::OffloadKind DeviceOffloadingKind) const {
  return {};
}
 
void ToolChain::AddIAMCUIncludeArgs(const ArgList &DriverArgs,
                                    ArgStringList &CC1Args) const {}
 
static VersionTuple separateMSVCFullVersion(unsigned Version) {
  if (Version < 100)
    return VersionTuple(Version);
 
  if (Version < 10000)
    return VersionTuple(Version / 100, Version % 100);
 
  unsigned Build = 0, Factor = 1;
  for (; Version > 10000; Version = Version / 10, Factor = Factor * 10)
    Build = Build + (Version % 10) * Factor;
  return VersionTuple(Version / 100, Version % 100, Build);
}
 
VersionTuple
ToolChain::computeMSVCVersion(const Driver *D,
                              const llvm::opt::ArgList &Args) const {
  const Arg *MSCVersion = Args.getLastArg(options::OPT_fmsc_version);
  const Arg *MSCompatibilityVersion =
      Args.getLastArg(options::OPT_fms_compatibility_version);
 
  if (MSCVersion && MSCompatibilityVersion) {
    if (D)
      D->Diag(diag::err_drv_argument_not_allowed_with)
          << MSCVersion->getAsString(Args)
          << MSCompatibilityVersion->getAsString(Args);
    return VersionTuple();
  }
 
  if (MSCompatibilityVersion) {
    VersionTuple MSVT;
    if (MSVT.tryParse(MSCompatibilityVersion->getValue())) {
      if (D)
        D->Diag(diag::err_drv_invalid_value)
            << MSCompatibilityVersion->getAsString(Args)
            << MSCompatibilityVersion->getValue();
    } else {
      return MSVT;
    }
  }
 
  if (MSCVersion) {
    unsigned Version = 0;
    if (StringRef(MSCVersion->getValue()).getAsInteger(10, Version)) {
      if (D)
        D->Diag(diag::err_drv_invalid_value)
            << MSCVersion->getAsString(Args) << MSCVersion->getValue();
    } else {
      return separateMSVCFullVersion(Version);
    }
  }
 
  return VersionTuple();
}
 
llvm::opt::DerivedArgList *ToolChain::TranslateOpenMPTargetArgs(
    const llvm::opt::DerivedArgList &Args, bool SameTripleAsHost,
    SmallVectorImpl<llvm::opt::Arg *> &AllocatedArgs) const {
  DerivedArgList *DAL = new DerivedArgList(Args.getBaseArgs());
  const OptTable &Opts = getDriver().getOpts();
  bool Modified = false;
 
  // Handle -Xopenmp-target flags
  for (auto *A : Args) {
    // Exclude flags which may only apply to the host toolchain.
    // Do not exclude flags when the host triple (AuxTriple)
    // matches the current toolchain triple. If it is not present
    // at all, target and host share a toolchain.
    if (A->getOption().matches(options::OPT_m_Group)) {
      // Pass certain options to the device toolchain even when the triple
      // differs from the host: code object version must be passed to correctly
      // set metadata in intermediate files; linker version must be passed
      // because the Darwin toolchain requires the host and device linker
      // versions to match (the host version is cached in
      // MachO::getLinkerVersion).
      if (SameTripleAsHost ||
          A->getOption().matches(options::OPT_mcode_object_version_EQ) ||
          A->getOption().matches(options::OPT_mlinker_version_EQ))
        DAL->append(A);
      else
        Modified = true;
      continue;
    }
 
    unsigned Index;
    unsigned Prev;
    bool XOpenMPTargetNoTriple =
        A->getOption().matches(options::OPT_Xopenmp_target);
 
    if (A->getOption().matches(options::OPT_Xopenmp_target_EQ)) {
      llvm::Triple TT = normalizeOffloadTriple(A->getValue(0));
 
      // Passing device args: -Xopenmp-target=<triple> -opt=val.
      if (TT.isCompatibleWith(getTriple()))
        Index = Args.getBaseArgs().MakeIndex(A->getValue(1));
      else
        continue;
    } else if (XOpenMPTargetNoTriple) {
      // Passing device args: -Xopenmp-target -opt=val.
      Index = Args.getBaseArgs().MakeIndex(A->getValue(0));
    } else {
      DAL->append(A);
      continue;
    }
 
    // Parse the argument to -Xopenmp-target.
    Prev = Index;
    std::unique_ptr<Arg> XOpenMPTargetArg(Opts.ParseOneArg(Args, Index));
    if (!XOpenMPTargetArg || Index > Prev + 1) {
      if (!A->isClaimed()) {
        getDriver().Diag(diag::err_drv_invalid_Xopenmp_target_with_args)
            << A->getAsString(Args);
      }
      continue;
    }
    if (XOpenMPTargetNoTriple && XOpenMPTargetArg &&
        Args.getAllArgValues(options::OPT_offload_targets_EQ).size() != 1) {
      getDriver().Diag(diag::err_drv_Xopenmp_target_missing_triple);
      continue;
    }
    XOpenMPTargetArg->setBaseArg(A);
    A = XOpenMPTargetArg.release();
    AllocatedArgs.push_back(A);
    DAL->append(A);
    Modified = true;
  }
 
  if (Modified)
    return DAL;
 
  delete DAL;
  return nullptr;
}
 
// TODO: Currently argument values separated by space e.g.
// -Xclang -mframe-pointer=no cannot be passed by -Xarch_. This should be
// fixed.
void ToolChain::TranslateXarchArgs(
    const llvm::opt::DerivedArgList &Args, llvm::opt::Arg *&A,
    llvm::opt::DerivedArgList *DAL,
    SmallVectorImpl<llvm::opt::Arg *> *AllocatedArgs) const {
  const OptTable &Opts = getDriver().getOpts();
  unsigned ValuePos = 1;
  if (A->getOption().matches(options::OPT_Xarch_device) ||
      A->getOption().matches(options::OPT_Xarch_host))
    ValuePos = 0;
 
  const InputArgList &BaseArgs = Args.getBaseArgs();
  unsigned Index = BaseArgs.MakeIndex(A->getValue(ValuePos));
  unsigned Prev = Index;
  std::unique_ptr<llvm::opt::Arg> XarchArg(Opts.ParseOneArg(
      Args, Index, llvm::opt::Visibility(options::ClangOption)));
 
  // If the argument parsing failed or more than one argument was
  // consumed, the -Xarch_ argument's parameter tried to consume
  // extra arguments. Emit an error and ignore.
  //
  // We also want to disallow any options which would alter the
  // driver behavior; that isn't going to work in our model. We
  // use options::NoXarchOption to control this.
  if (!XarchArg || Index > Prev + 1) {
    getDriver().Diag(diag::err_drv_invalid_Xarch_argument_with_args)
        << A->getAsString(Args);
    return;
  } else if (XarchArg->getOption().hasFlag(options::NoXarchOption)) {
    auto &Diags = getDriver().getDiags();
    unsigned DiagID =
        Diags.getCustomDiagID(DiagnosticsEngine::Error,
                              "invalid Xarch argument: '%0', not all driver "
                              "options can be forwared via Xarch argument");
    Diags.Report(DiagID) << A->getAsString(Args);
    return;
  }
 
  XarchArg->setBaseArg(A);
  A = XarchArg.release();
 
  // Linker input arguments require custom handling. The problem is that we
  // have already constructed the phase actions, so we can not treat them as
  // "input arguments".
  if (A->getOption().hasFlag(options::LinkerInput)) {
    // Convert the argument into individual Zlinker_input_args. Need to do this
    // manually to avoid memory leaks with the allocated arguments.
    for (const char *Value : A->getValues()) {
      auto Opt = Opts.getOption(options::OPT_Zlinker_input);
      unsigned Index = BaseArgs.MakeIndex(Opt.getName(), Value);
      auto NewArg =
          new Arg(Opt, BaseArgs.MakeArgString(Opt.getPrefix() + Opt.getName()),
                  Index, BaseArgs.getArgString(Index + 1), A);
 
      DAL->append(NewArg);
      if (!AllocatedArgs)
        DAL->AddSynthesizedArg(NewArg);
      else
        AllocatedArgs->push_back(NewArg);
    }
  }
 
  if (!AllocatedArgs)
    DAL->AddSynthesizedArg(A);
  else
    AllocatedArgs->push_back(A);
}
 
/// Match any triple recognized arch aliases.
static bool isXArchCompatibleTripleArch(const llvm::Triple &TT,
                                        StringRef XArchVal) {
  llvm::Triple ParsedTriple(XArchVal);
  return TT.getArch() == ParsedTriple.getArch() &&
         TT.getSubArch() == ParsedTriple.getSubArch();
}
 
llvm::opt::DerivedArgList *ToolChain::TranslateXarchArgs(
    const llvm::opt::DerivedArgList &Args, StringRef BoundArch,
    Action::OffloadKind OFK,
    SmallVectorImpl<llvm::opt::Arg *> *AllocatedArgs) const {
  DerivedArgList *DAL = new DerivedArgList(Args.getBaseArgs());
  bool Modified = false;
 
  bool IsDevice = OFK != Action::OFK_None && OFK != Action::OFK_Host;
  for (Arg *A : Args) {
    bool NeedTrans = false;
    bool Skip = false;
    if (A->getOption().matches(options::OPT_Xarch_device)) {
      NeedTrans = IsDevice;
      Skip = !IsDevice;
    } else if (A->getOption().matches(options::OPT_Xarch_host)) {
      NeedTrans = !IsDevice;
      Skip = IsDevice;
    } else if (A->getOption().matches(options::OPT_Xarch__)) {
      StringRef Val = A->getValue();
      NeedTrans = Val == getArchName() ||
                  (!BoundArch.empty() && Val == BoundArch) ||
                  isXArchCompatibleTripleArch(Triple, Val);
      Skip = !NeedTrans;
    }
    if (NeedTrans || Skip)
      Modified = true;
    if (NeedTrans) {
      A->claim();
      TranslateXarchArgs(Args, A, DAL, AllocatedArgs);
    }
    if (!Skip)
      DAL->append(A);
  }
 
  if (Modified)
    return DAL;
 
  delete DAL;
  return nullptr;
}