C++ Compilation类代码示例

void solaris::Assembler::ConstructJob(Compilation &C, const JobAction &JA,
                                      const InputInfo &Output,
                                      const InputInfoList &Inputs,
                                      const ArgList &Args,
                                      const char *LinkingOutput) const {
  claimNoWarnArgs(Args);
  ArgStringList CmdArgs;

  Args.AddAllArgValues(CmdArgs, options::OPT_Wa_COMMA, options::OPT_Xassembler);

  CmdArgs.push_back("-o");
  CmdArgs.push_back(Output.getFilename());

  for (const auto &II : Inputs)
    CmdArgs.push_back(II.getFilename());

  const char *Exec = Args.MakeArgString(getToolChain().GetProgramPath("as"));
  C.addCommand(llvm::make_unique<Command>(JA, *this, Exec, CmdArgs, Inputs));
}

// All inputs to this linker must be from CudaDeviceActions, as we need to look
// at the Inputs' Actions in order to figure out which GPU architecture they
// correspond to.
void NVPTX::Linker::ConstructJob(Compilation &C, const JobAction &JA,
                                 const InputInfo &Output,
                                 const InputInfoList &Inputs,
                                 const ArgList &Args,
                                 const char *LinkingOutput) const {
  const auto &TC =
      static_cast<const toolchains::CudaToolChain &>(getToolChain());
  assert(TC.getTriple().isNVPTX() && "Wrong platform");

  ArgStringList CmdArgs;
  CmdArgs.push_back("--cuda");
  CmdArgs.push_back(TC.getTriple().isArch64Bit() ? "-64" : "-32");
  CmdArgs.push_back(Args.MakeArgString("--create"));
  CmdArgs.push_back(Args.MakeArgString(Output.getFilename()));

  for (const auto& II : Inputs) {
    auto *A = II.getAction();
    assert(A->getInputs().size() == 1 &&
           "Device offload action is expected to have a single input");
    const char *gpu_arch_str = A->getOffloadingArch();
    assert(gpu_arch_str &&
           "Device action expected to have associated a GPU architecture!");
    CudaArch gpu_arch = StringToCudaArch(gpu_arch_str);

    // We need to pass an Arch of the form "sm_XX" for cubin files and
    // "compute_XX" for ptx.
    const char *Arch =
        (II.getType() == types::TY_PP_Asm)
            ? CudaVirtualArchToString(VirtualArchForCudaArch(gpu_arch))
            : gpu_arch_str;
    CmdArgs.push_back(Args.MakeArgString(llvm::Twine("--image=profile=") +
                                         Arch + ",file=" + II.getFilename()));
  }

  for (const auto& A : Args.getAllArgValues(options::OPT_Xcuda_fatbinary))
    CmdArgs.push_back(Args.MakeArgString(A));

  const char *Exec = Args.MakeArgString(TC.GetProgramPath("fatbinary"));
  C.addCommand(llvm::make_unique<Command>(JA, *this, Exec, CmdArgs, Inputs));
}

void wasm::Linker::ConstructJob(Compilation &C, const JobAction &JA,
                                const InputInfo &Output,
                                const InputInfoList &Inputs,
                                const ArgList &Args,
                                const char *LinkingOutput) const {

  const ToolChain &ToolChain = getToolChain();
  const char *Linker = Args.MakeArgString(ToolChain.GetLinkerPath());
  ArgStringList CmdArgs;

  if (Args.hasArg(options::OPT_s))
    CmdArgs.push_back("--strip-all");

  Args.AddAllArgs(CmdArgs, options::OPT_L);
  Args.AddAllArgs(CmdArgs, options::OPT_u);
  ToolChain.AddFilePathLibArgs(Args, CmdArgs);

  if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nostartfiles))
    CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("crt1.o")));

  AddLinkerInputs(ToolChain, Inputs, Args, CmdArgs, JA);

  if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs)) {
    if (ToolChain.ShouldLinkCXXStdlib(Args))
      ToolChain.AddCXXStdlibLibArgs(Args, CmdArgs);

    if (Args.hasArg(options::OPT_pthread))
      CmdArgs.push_back("-lpthread");

    CmdArgs.push_back("-lc");
    AddRunTimeLibs(ToolChain, ToolChain.getDriver(), CmdArgs, Args);
  }

  CmdArgs.push_back("-o");
  CmdArgs.push_back(Output.getFilename());

  C.addCommand(llvm::make_unique<Command>(JA, *this, Linker, CmdArgs, Inputs));
}

void hexagon::Assembler::ConstructJob(Compilation &C, const JobAction &JA,
                                      const InputInfo &Output,
                                      const InputInfoList &Inputs,
                                      const ArgList &Args,
                                      const char *LinkingOutput) const {
  claimNoWarnArgs(Args);

  auto &HTC = static_cast<const toolchains::HexagonToolChain&>(getToolChain());
  const Driver &D = HTC.getDriver();
  ArgStringList CmdArgs;

  std::string MArchString = "-march=hexagon";
  CmdArgs.push_back(Args.MakeArgString(MArchString));

  RenderExtraToolArgs(JA, CmdArgs);

  std::string AsName = "hexagon-llvm-mc";
  std::string MCpuString = "-mcpu=hexagon" +
        toolchains::HexagonToolChain::GetTargetCPUVersion(Args).str();
  CmdArgs.push_back("-filetype=obj");
  CmdArgs.push_back(Args.MakeArgString(MCpuString));

  if (Output.isFilename()) {
    CmdArgs.push_back("-o");
    CmdArgs.push_back(Output.getFilename());
  } else {
    assert(Output.isNothing() && "Unexpected output");
    CmdArgs.push_back("-fsyntax-only");
  }

  if (auto G = toolchains::HexagonToolChain::getSmallDataThreshold(Args)) {
    std::string N = llvm::utostr(G.getValue());
    CmdArgs.push_back(Args.MakeArgString(std::string("-gpsize=") + N));
  }

  Args.AddAllArgValues(CmdArgs, options::OPT_Wa_COMMA, options::OPT_Xassembler);

  // Only pass -x if gcc will understand it; otherwise hope gcc
  // understands the suffix correctly. The main use case this would go
  // wrong in is for linker inputs if they happened to have an odd
  // suffix; really the only way to get this to happen is a command
  // like '-x foobar a.c' which will treat a.c like a linker input.
  //
  // FIXME: For the linker case specifically, can we safely convert
  // inputs into '-Wl,' options?
  for (const auto &II : Inputs) {
    // Don't try to pass LLVM or AST inputs to a generic gcc.
    if (types::isLLVMIR(II.getType()))
      D.Diag(clang::diag::err_drv_no_linker_llvm_support)
          << HTC.getTripleString();
    else if (II.getType() == types::TY_AST)
      D.Diag(clang::diag::err_drv_no_ast_support)
          << HTC.getTripleString();
    else if (II.getType() == types::TY_ModuleFile)
      D.Diag(diag::err_drv_no_module_support)
          << HTC.getTripleString();

    if (II.isFilename())
      CmdArgs.push_back(II.getFilename());
    else
      // Don't render as input, we need gcc to do the translations.
      // FIXME: What is this?
      II.getInputArg().render(Args, CmdArgs);
  }

  auto *Exec = Args.MakeArgString(HTC.GetProgramPath(AsName.c_str()));
  C.addCommand(llvm::make_unique<Command>(JA, *this, Exec, CmdArgs, Inputs));
}

void netbsd::Linker::ConstructJob(Compilation &C, const JobAction &JA,
                                  const InputInfo &Output,
                                  const InputInfoList &Inputs,
                                  const ArgList &Args,
                                  const char *LinkingOutput) const {
  const Driver &D = getToolChain().getDriver();
  ArgStringList CmdArgs;

  if (!D.SysRoot.empty())
    CmdArgs.push_back(Args.MakeArgString("--sysroot=" + D.SysRoot));

  CmdArgs.push_back("--eh-frame-hdr");
  if (Args.hasArg(options::OPT_static)) {
    CmdArgs.push_back("-Bstatic");
  } else {
    if (Args.hasArg(options::OPT_rdynamic))
      CmdArgs.push_back("-export-dynamic");
    if (Args.hasArg(options::OPT_shared)) {
      CmdArgs.push_back("-Bshareable");
    } else {
      Args.AddAllArgs(CmdArgs, options::OPT_pie);
      CmdArgs.push_back("-dynamic-linker");
      CmdArgs.push_back("/libexec/ld.elf_so");
    }
  }

  // Many NetBSD architectures support more than one ABI.
  // Determine the correct emulation for ld.
  switch (getToolChain().getArch()) {
  case llvm::Triple::x86:
    CmdArgs.push_back("-m");
    CmdArgs.push_back("elf_i386");
    break;
  case llvm::Triple::arm:
  case llvm::Triple::thumb:
    CmdArgs.push_back("-m");
    switch (getToolChain().getTriple().getEnvironment()) {
    case llvm::Triple::EABI:
    case llvm::Triple::GNUEABI:
      CmdArgs.push_back("armelf_nbsd_eabi");
      break;
    case llvm::Triple::EABIHF:
    case llvm::Triple::GNUEABIHF:
      CmdArgs.push_back("armelf_nbsd_eabihf");
      break;
    default:
      CmdArgs.push_back("armelf_nbsd");
      break;
    }
    break;
  case llvm::Triple::armeb:
  case llvm::Triple::thumbeb:
    arm::appendEBLinkFlags(Args, CmdArgs, getToolChain().getEffectiveTriple());
    CmdArgs.push_back("-m");
    switch (getToolChain().getTriple().getEnvironment()) {
    case llvm::Triple::EABI:
    case llvm::Triple::GNUEABI:
      CmdArgs.push_back("armelfb_nbsd_eabi");
      break;
    case llvm::Triple::EABIHF:
    case llvm::Triple::GNUEABIHF:
      CmdArgs.push_back("armelfb_nbsd_eabihf");
      break;
    default:
      CmdArgs.push_back("armelfb_nbsd");
      break;
    }
    break;
  case llvm::Triple::mips64:
  case llvm::Triple::mips64el:
    if (mips::hasMipsAbiArg(Args, "32")) {
      CmdArgs.push_back("-m");
      if (getToolChain().getArch() == llvm::Triple::mips64)
        CmdArgs.push_back("elf32btsmip");
      else
        CmdArgs.push_back("elf32ltsmip");
    } else if (mips::hasMipsAbiArg(Args, "64")) {
      CmdArgs.push_back("-m");
      if (getToolChain().getArch() == llvm::Triple::mips64)
        CmdArgs.push_back("elf64btsmip");
      else
        CmdArgs.push_back("elf64ltsmip");
    }
    break;
  case llvm::Triple::ppc:
    CmdArgs.push_back("-m");
    CmdArgs.push_back("elf32ppc_nbsd");
    break;

  case llvm::Triple::ppc64:
  case llvm::Triple::ppc64le:
    CmdArgs.push_back("-m");
    CmdArgs.push_back("elf64ppc");
    break;

  case llvm::Triple::sparc:
    CmdArgs.push_back("-m");
    CmdArgs.push_back("elf32_sparc");
    break;

//.........这里部分代码省略.........

void Driver::BuildJobsForAction(Compilation &C,
                                const Action *A,
                                const ToolChain *TC,
                                bool CanAcceptPipe,
                                bool AtTopLevel,
                                const char *LinkingOutput,
                                InputInfo &Result) const {
  llvm::PrettyStackTraceString CrashInfo("Building compilation jobs for action");

  bool UsePipes = C.getArgs().hasArg(options::OPT_pipe);
  // FIXME: Pipes are forcibly disabled until we support executing
  // them.
  if (!CCCPrintBindings)
    UsePipes = false;

  if (const InputAction *IA = dyn_cast<InputAction>(A)) {
    // FIXME: It would be nice to not claim this here; maybe the old
    // scheme of just using Args was better?
    const Arg &Input = IA->getInputArg();
    Input.claim();
    if (isa<PositionalArg>(Input)) {
      const char *Name = Input.getValue(C.getArgs());
      Result = InputInfo(Name, A->getType(), Name);
    } else
      Result = InputInfo(&Input, A->getType(), "");
    return;
  }

  if (const BindArchAction *BAA = dyn_cast<BindArchAction>(A)) {
    const char *ArchName = BAA->getArchName();
    std::string Arch;
    if (!ArchName) {
      Arch = C.getDefaultToolChain().getArchName();
      ArchName = Arch.c_str();
    }
    BuildJobsForAction(C,
                       *BAA->begin(), 
                       Host->getToolChain(C.getArgs(), ArchName),
                       CanAcceptPipe,
                       AtTopLevel,
                       LinkingOutput,
                       Result);
    return;
  }

  const JobAction *JA = cast<JobAction>(A);
  const Tool &T = TC->SelectTool(C, *JA);
  
  // See if we should use an integrated preprocessor. We do so when we
  // have exactly one input, since this is the only use case we care
  // about (irrelevant since we don't support combine yet).
  bool UseIntegratedCPP = false;
  const ActionList *Inputs = &A->getInputs();
  if (Inputs->size() == 1 && isa<PreprocessJobAction>(*Inputs->begin())) {
    if (!C.getArgs().hasArg(options::OPT_no_integrated_cpp) &&
        !C.getArgs().hasArg(options::OPT_traditional_cpp) &&
        !C.getArgs().hasArg(options::OPT_save_temps) &&
        T.hasIntegratedCPP()) {
      UseIntegratedCPP = true;
      Inputs = &(*Inputs)[0]->getInputs();
    }
  }

  // Only use pipes when there is exactly one input.
  bool TryToUsePipeInput = Inputs->size() == 1 && T.acceptsPipedInput();
  InputInfoList InputInfos;
  for (ActionList::const_iterator it = Inputs->begin(), ie = Inputs->end();
       it != ie; ++it) {
    InputInfo II;
    BuildJobsForAction(C, *it, TC, TryToUsePipeInput, 
                       /*AtTopLevel*/false,
                       LinkingOutput,
                       II);
    InputInfos.push_back(II);
  }

  // Determine if we should output to a pipe.
  bool OutputToPipe = false;
  if (CanAcceptPipe && T.canPipeOutput()) {
    // Some actions default to writing to a pipe if they are the top
    // level phase and there was no user override.
    //
    // FIXME: Is there a better way to handle this?
    if (AtTopLevel) {
      if (isa<PreprocessJobAction>(A) && !C.getArgs().hasArg(options::OPT_o))
        OutputToPipe = true;
    } else if (UsePipes)
      OutputToPipe = true;
  }

  // Figure out where to put the job (pipes).
  Job *Dest = &C.getJobs();
  if (InputInfos[0].isPipe()) {
    assert(TryToUsePipeInput && "Unrequested pipe!");
    assert(InputInfos.size() == 1 && "Unexpected pipe with multiple inputs.");
    Dest = &InputInfos[0].getPipe();
  }

  // Always use the first input as the base input.
  const char *BaseInput = InputInfos[0].getBaseInput();
//.........这里部分代码省略.........

void openbsd::Assembler::ConstructJob(Compilation &C, const JobAction &JA,
                                      const InputInfo &Output,
                                      const InputInfoList &Inputs,
                                      const ArgList &Args,
                                      const char *LinkingOutput) const {
  claimNoWarnArgs(Args);
  ArgStringList CmdArgs;

  switch (getToolChain().getArch()) {
  case llvm::Triple::x86:
    // When building 32-bit code on OpenBSD/amd64, we have to explicitly
    // instruct as in the base system to assemble 32-bit code.
    CmdArgs.push_back("--32");
    break;

  case llvm::Triple::ppc:
    CmdArgs.push_back("-mppc");
    CmdArgs.push_back("-many");
    break;

  case llvm::Triple::sparc:
  case llvm::Triple::sparcel: {
    CmdArgs.push_back("-32");
    std::string CPU = getCPUName(Args, getToolChain().getTriple());
    CmdArgs.push_back(sparc::getSparcAsmModeForCPU(CPU, getToolChain().getTriple()));
    AddAssemblerKPIC(getToolChain(), Args, CmdArgs);
    break;
  }

  case llvm::Triple::sparcv9: {
    CmdArgs.push_back("-64");
    std::string CPU = getCPUName(Args, getToolChain().getTriple());
    CmdArgs.push_back(sparc::getSparcAsmModeForCPU(CPU, getToolChain().getTriple()));
    AddAssemblerKPIC(getToolChain(), Args, CmdArgs);
    break;
  }

  case llvm::Triple::mips64:
  case llvm::Triple::mips64el: {
    StringRef CPUName;
    StringRef ABIName;
    mips::getMipsCPUAndABI(Args, getToolChain().getTriple(), CPUName, ABIName);

    CmdArgs.push_back("-mabi");
    CmdArgs.push_back(mips::getGnuCompatibleMipsABIName(ABIName).data());

    if (getToolChain().getArch() == llvm::Triple::mips64)
      CmdArgs.push_back("-EB");
    else
      CmdArgs.push_back("-EL");

    AddAssemblerKPIC(getToolChain(), Args, CmdArgs);
    break;
  }

  default:
    break;
  }

  Args.AddAllArgValues(CmdArgs, options::OPT_Wa_COMMA, options::OPT_Xassembler);

  CmdArgs.push_back("-o");
  CmdArgs.push_back(Output.getFilename());

  for (const auto &II : Inputs)
    CmdArgs.push_back(II.getFilename());

  const char *Exec = Args.MakeArgString(getToolChain().GetProgramPath("as"));
  C.addCommand(llvm::make_unique<Command>(JA, *this, Exec, CmdArgs, Inputs));
}

void freebsd::Assembler::ConstructJob(Compilation &C, const JobAction &JA,
                                      const InputInfo &Output,
                                      const InputInfoList &Inputs,
                                      const ArgList &Args,
                                      const char *LinkingOutput) const {
  claimNoWarnArgs(Args);
  ArgStringList CmdArgs;

  // When building 32-bit code on FreeBSD/amd64, we have to explicitly
  // instruct as in the base system to assemble 32-bit code.
  switch (getToolChain().getArch()) {
  default:
    break;
  case llvm::Triple::x86:
    CmdArgs.push_back("--32");
    break;
  case llvm::Triple::ppc:
    CmdArgs.push_back("-a32");
    break;
  case llvm::Triple::mips:
  case llvm::Triple::mipsel:
  case llvm::Triple::mips64:
  case llvm::Triple::mips64el: {
    StringRef CPUName;
    StringRef ABIName;
    mips::getMipsCPUAndABI(Args, getToolChain().getTriple(), CPUName, ABIName);

    CmdArgs.push_back("-march");
    CmdArgs.push_back(CPUName.data());

    CmdArgs.push_back("-mabi");
    CmdArgs.push_back(mips::getGnuCompatibleMipsABIName(ABIName).data());

    if (getToolChain().getTriple().isLittleEndian())
      CmdArgs.push_back("-EL");
    else
      CmdArgs.push_back("-EB");

    if (Arg *A = Args.getLastArg(options::OPT_G)) {
      StringRef v = A->getValue();
      CmdArgs.push_back(Args.MakeArgString("-G" + v));
      A->claim();
    }

    AddAssemblerKPIC(getToolChain(), Args, CmdArgs);
    break;
  }
  case llvm::Triple::arm:
  case llvm::Triple::armeb:
  case llvm::Triple::thumb:
  case llvm::Triple::thumbeb: {
    arm::FloatABI ABI = arm::getARMFloatABI(getToolChain(), Args);

    if (ABI == arm::FloatABI::Hard)
      CmdArgs.push_back("-mfpu=vfp");
    else
      CmdArgs.push_back("-mfpu=softvfp");

    switch (getToolChain().getTriple().getEnvironment()) {
    case llvm::Triple::GNUEABIHF:
    case llvm::Triple::GNUEABI:
    case llvm::Triple::EABI:
      CmdArgs.push_back("-meabi=5");
      break;

    default:
      CmdArgs.push_back("-matpcs");
    }
    break;
  }
  case llvm::Triple::sparc:
  case llvm::Triple::sparcel:
  case llvm::Triple::sparcv9: {
    std::string CPU = getCPUName(Args, getToolChain().getTriple());
    CmdArgs.push_back(sparc::getSparcAsmModeForCPU(CPU, getToolChain().getTriple()));
    AddAssemblerKPIC(getToolChain(), Args, CmdArgs);
    break;
  }
  }

  Args.AddAllArgValues(CmdArgs, options::OPT_Wa_COMMA, options::OPT_Xassembler);

  CmdArgs.push_back("-o");
  CmdArgs.push_back(Output.getFilename());

  for (const auto &II : Inputs)
    CmdArgs.push_back(II.getFilename());

  const char *Exec = Args.MakeArgString(getToolChain().GetProgramPath("as"));
  C.addCommand(llvm::make_unique<Command>(JA, *this, Exec, CmdArgs, Inputs));
}

Compilation *Driver::BuildCompilation(int argc, const char **argv) {
    llvm::PrettyStackTraceString CrashInfo("Compilation construction");

    // FIXME: Handle environment options which effect driver behavior, somewhere
    // (client?). GCC_EXEC_PREFIX, COMPILER_PATH, LIBRARY_PATH, LPATH,
    // CC_PRINT_OPTIONS.

    // FIXME: What are we going to do with -V and -b?

    // FIXME: This stuff needs to go into the Compilation, not the driver.
    bool CCCPrintOptions = false, CCCPrintActions = false;

    const char **Start = argv + 1, **End = argv + argc;
    const char *HostTriple = DefaultHostTriple.c_str();

    InputArgList *Args = ParseArgStrings(Start, End);

    // -no-canonical-prefixes is used very early in main.
    Args->ClaimAllArgs(options::OPT_no_canonical_prefixes);

    // Extract -ccc args.
    //
    // FIXME: We need to figure out where this behavior should live. Most of it
    // should be outside in the client; the parts that aren't should have proper
    // options, either by introducing new ones or by overloading gcc ones like -V
    // or -b.
    CCCPrintOptions = Args->hasArg(options::OPT_ccc_print_options);
    CCCPrintActions = Args->hasArg(options::OPT_ccc_print_phases);
    CCCPrintBindings = Args->hasArg(options::OPT_ccc_print_bindings);
    CCCIsCXX = Args->hasArg(options::OPT_ccc_cxx) || CCCIsCXX;
    CCCEcho = Args->hasArg(options::OPT_ccc_echo);
    if (const Arg *A = Args->getLastArg(options::OPT_ccc_gcc_name))
        CCCGenericGCCName = A->getValue(*Args);
    CCCUseClangCXX = Args->hasFlag(options::OPT_ccc_clang_cxx,
                                   options::OPT_ccc_no_clang_cxx,
                                   CCCUseClangCXX);
    CCCUsePCH = Args->hasFlag(options::OPT_ccc_pch_is_pch,
                              options::OPT_ccc_pch_is_pth);
    CCCUseClang = !Args->hasArg(options::OPT_ccc_no_clang);
    CCCUseClangCPP = !Args->hasArg(options::OPT_ccc_no_clang_cpp);
    if (const Arg *A = Args->getLastArg(options::OPT_ccc_clang_archs)) {
        llvm::StringRef Cur = A->getValue(*Args);

        CCCClangArchs.clear();
        while (!Cur.empty()) {
            std::pair<llvm::StringRef, llvm::StringRef> Split = Cur.split(',');

            if (!Split.first.empty()) {
                llvm::Triple::ArchType Arch =
                    llvm::Triple(Split.first, "", "").getArch();

                if (Arch == llvm::Triple::UnknownArch)
                    Diag(clang::diag::err_drv_invalid_arch_name) << Split.first;

                CCCClangArchs.insert(Arch);
            }

            Cur = Split.second;
        }
    }
    if (const Arg *A = Args->getLastArg(options::OPT_ccc_host_triple))
        HostTriple = A->getValue(*Args);
    if (const Arg *A = Args->getLastArg(options::OPT_ccc_install_dir))
        Dir = A->getValue(*Args);

    Host = GetHostInfo(HostTriple);

    // The compilation takes ownership of Args.
    Compilation *C = new Compilation(*this, *Host->CreateToolChain(*Args), Args);

    // FIXME: This behavior shouldn't be here.
    if (CCCPrintOptions) {
        PrintOptions(C->getArgs());
        return C;
    }

    if (!HandleImmediateArgs(*C))
        return C;

    // Construct the list of abstract actions to perform for this compilation. We
    // avoid passing a Compilation here simply to enforce the abstraction that
    // pipelining is not host or toolchain dependent (other than the driver driver
    // test).
    if (Host->useDriverDriver())
        BuildUniversalActions(C->getArgs(), C->getActions());
    else
        BuildActions(C->getArgs(), C->getActions());

    if (CCCPrintActions) {
        PrintActions(*C);
        return C;
    }

    BuildJobs(*C);

    return C;
}

/// Add OpenMP linker script arguments at the end of the argument list so that
/// the fat binary is built by embedding each of the device images into the
/// host. The linker script also defines a few symbols required by the code
/// generation so that the images can be easily retrieved at runtime by the
/// offloading library. This should be used only in tool chains that support
/// linker scripts.
void tools::AddOpenMPLinkerScript(const ToolChain &TC, Compilation &C,
                                  const InputInfo &Output,
                                  const InputInfoList &Inputs,
                                  const ArgList &Args, ArgStringList &CmdArgs,
                                  const JobAction &JA) {

  // If this is not an OpenMP host toolchain, we don't need to do anything.
  if (!JA.isHostOffloading(Action::OFK_OpenMP))
    return;

  // Create temporary linker script. Keep it if save-temps is enabled.
  const char *LKS;
  SmallString<256> Name = llvm::sys::path::filename(Output.getFilename());
  if (C.getDriver().isSaveTempsEnabled()) {
    llvm::sys::path::replace_extension(Name, "lk");
    LKS = C.getArgs().MakeArgString(Name.c_str());
  } else {
    llvm::sys::path::replace_extension(Name, "");
    Name = C.getDriver().GetTemporaryPath(Name, "lk");
    LKS = C.addTempFile(C.getArgs().MakeArgString(Name.c_str()));
  }

  // Add linker script option to the command.
  CmdArgs.push_back("-T");
  CmdArgs.push_back(LKS);

  // Create a buffer to write the contents of the linker script.
  std::string LksBuffer;
  llvm::raw_string_ostream LksStream(LksBuffer);

  // Get the OpenMP offload tool chains so that we can extract the triple
  // associated with each device input.
  auto OpenMPToolChains = C.getOffloadToolChains<Action::OFK_OpenMP>();
  assert(OpenMPToolChains.first != OpenMPToolChains.second &&
         "No OpenMP toolchains??");

  // Track the input file name and device triple in order to build the script,
  // inserting binaries in the designated sections.
  SmallVector<std::pair<std::string, const char *>, 8> InputBinaryInfo;

  // Add commands to embed target binaries. We ensure that each section and
  // image is 16-byte aligned. This is not mandatory, but increases the
  // likelihood of data to be aligned with a cache block in several main host
  // machines.
  LksStream << "/*\n";
  LksStream << "       OpenMP Offload Linker Script\n";
  LksStream << " *** Automatically generated by Clang ***\n";
  LksStream << "*/\n";
  LksStream << "TARGET(binary)\n";
  auto DTC = OpenMPToolChains.first;
  for (auto &II : Inputs) {
    const Action *A = II.getAction();
    // Is this a device linking action?
    if (A && isa<LinkJobAction>(A) &&
        A->isDeviceOffloading(Action::OFK_OpenMP)) {
      assert(DTC != OpenMPToolChains.second &&
             "More device inputs than device toolchains??");
      InputBinaryInfo.push_back(std::make_pair(
          DTC->second->getTriple().normalize(), II.getFilename()));
      ++DTC;
      LksStream << "INPUT(" << II.getFilename() << ")\n";
    }
  }

  assert(DTC == OpenMPToolChains.second &&
         "Less device inputs than device toolchains??");

  LksStream << "SECTIONS\n";
  LksStream << "{\n";

  // Put each target binary into a separate section.
  for (const auto &BI : InputBinaryInfo) {
    LksStream << "  .omp_offloading." << BI.first << " :\n";
    LksStream << "  ALIGN(0x10)\n";
    LksStream << "  {\n";
    LksStream << "    PROVIDE_HIDDEN(.omp_offloading.img_start." << BI.first
              << " = .);\n";
    LksStream << "    " << BI.second << "\n";
    LksStream << "    PROVIDE_HIDDEN(.omp_offloading.img_end." << BI.first
              << " = .);\n";
    LksStream << "  }\n";
  }

  // Add commands to define host entries begin and end. We use 1-byte subalign
  // so that the linker does not add any padding and the elements in this
  // section form an array.
  LksStream << "  .omp_offloading.entries :\n";
  LksStream << "  ALIGN(0x10)\n";
  LksStream << "  SUBALIGN(0x01)\n";
  LksStream << "  {\n";
  LksStream << "    PROVIDE_HIDDEN(.omp_offloading.entries_begin = .);\n";
  LksStream << "    *(.omp_offloading.entries)\n";
  LksStream << "    PROVIDE_HIDDEN(.omp_offloading.entries_end = .);\n";
  LksStream << "  }\n";
//.........这里部分代码省略.........

void wasm::Linker::ConstructJob(Compilation &C, const JobAction &JA,
                                const InputInfo &Output,
                                const InputInfoList &Inputs,
                                const ArgList &Args,
                                const char *LinkingOutput) const {

  const ToolChain &ToolChain = getToolChain();
  const Driver &D = ToolChain.getDriver();
  const char *Linker = Args.MakeArgString(ToolChain.GetLinkerPath());
  ArgStringList CmdArgs;
  CmdArgs.push_back("-flavor");
  CmdArgs.push_back("ld");

  // Enable garbage collection of unused input sections by default, since code
  // size is of particular importance. This is significantly facilitated by
  // the enabling of -ffunction-sections and -fdata-sections in
  // Clang::ConstructJob.
  if (areOptimizationsEnabled(Args))
    CmdArgs.push_back("--gc-sections");

  if (Args.hasArg(options::OPT_rdynamic))
    CmdArgs.push_back("-export-dynamic");
  if (Args.hasArg(options::OPT_s))
    CmdArgs.push_back("--strip-all");
  if (Args.hasArg(options::OPT_shared))
    CmdArgs.push_back("-shared");
  if (Args.hasArg(options::OPT_static))
    CmdArgs.push_back("-Bstatic");

  Args.AddAllArgs(CmdArgs, options::OPT_L);
  ToolChain.AddFilePathLibArgs(Args, CmdArgs);

  if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nostartfiles)) {
    if (Args.hasArg(options::OPT_shared))
      CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("rcrt1.o")));
    else if (Args.hasArg(options::OPT_pie))
      CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("Scrt1.o")));
    else
      CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("crt1.o")));

    CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("crti.o")));
  }

  AddLinkerInputs(ToolChain, Inputs, Args, CmdArgs, JA);

  if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs)) {
    if (D.CCCIsCXX())
      ToolChain.AddCXXStdlibLibArgs(Args, CmdArgs);

    if (Args.hasArg(options::OPT_pthread))
      CmdArgs.push_back("-lpthread");

    CmdArgs.push_back("-lc");
    CmdArgs.push_back("-lcompiler_rt");
  }

  if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nostartfiles))
    CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("crtn.o")));

  CmdArgs.push_back("-o");
  CmdArgs.push_back(Output.getFilename());

  C.addCommand(llvm::make_unique<Command>(JA, *this, Linker, CmdArgs, Inputs));
}

 InstructionMark(Compilation* compilation, Instruction* instr) {
   _compilation = compilation;
   _previous = _compilation->set_current_instruction(instr);
 }

void openbsd::Linker::ConstructJob(Compilation &C, const JobAction &JA,
                                   const InputInfo &Output,
                                   const InputInfoList &Inputs,
                                   const ArgList &Args,
                                   const char *LinkingOutput) const {
  const toolchains::OpenBSD &ToolChain =
      static_cast<const toolchains::OpenBSD &>(getToolChain());
  const Driver &D = getToolChain().getDriver();
  ArgStringList CmdArgs;

  // Silence warning for "clang -g foo.o -o foo"
  Args.ClaimAllArgs(options::OPT_g_Group);
  // and "clang -emit-llvm foo.o -o foo"
  Args.ClaimAllArgs(options::OPT_emit_llvm);
  // and for "clang -w foo.o -o foo". Other warning options are already
  // handled somewhere else.
  Args.ClaimAllArgs(options::OPT_w);

  if (getToolChain().getArch() == llvm::Triple::mips64)
    CmdArgs.push_back("-EB");
  else if (getToolChain().getArch() == llvm::Triple::mips64el)
    CmdArgs.push_back("-EL");

  if (!Args.hasArg(options::OPT_nostdlib, options::OPT_shared)) {
    CmdArgs.push_back("-e");
    CmdArgs.push_back("__start");
  }

  CmdArgs.push_back("--eh-frame-hdr");
  if (Args.hasArg(options::OPT_static)) {
    CmdArgs.push_back("-Bstatic");
  } else {
    if (Args.hasArg(options::OPT_rdynamic))
      CmdArgs.push_back("-export-dynamic");
    CmdArgs.push_back("-Bdynamic");
    if (Args.hasArg(options::OPT_shared)) {
      CmdArgs.push_back("-shared");
    } else {
      CmdArgs.push_back("-dynamic-linker");
      CmdArgs.push_back("/usr/libexec/ld.so");
    }
  }

  if (Args.hasArg(options::OPT_pie))
    CmdArgs.push_back("-pie");
  if (Args.hasArg(options::OPT_nopie))
    CmdArgs.push_back("-nopie");

  if (Output.isFilename()) {
    CmdArgs.push_back("-o");
    CmdArgs.push_back(Output.getFilename());
  } else {
    assert(Output.isNothing() && "Invalid output.");
  }

  if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nostartfiles)) {
    if (!Args.hasArg(options::OPT_shared)) {
      if (Args.hasArg(options::OPT_pg))
        CmdArgs.push_back(
            Args.MakeArgString(getToolChain().GetFilePath("gcrt0.o")));
      else if (Args.hasArg(options::OPT_static) &&
               !Args.hasArg(options::OPT_nopie))
        CmdArgs.push_back(
            Args.MakeArgString(getToolChain().GetFilePath("rcrt0.o")));
      else
        CmdArgs.push_back(
            Args.MakeArgString(getToolChain().GetFilePath("crt0.o")));
      CmdArgs.push_back(
          Args.MakeArgString(getToolChain().GetFilePath("crtbegin.o")));
    } else {
      CmdArgs.push_back(
          Args.MakeArgString(getToolChain().GetFilePath("crtbeginS.o")));
    }
  }

  std::string Triple = getToolChain().getTripleString();
  if (Triple.substr(0, 6) == "x86_64")
    Triple.replace(0, 6, "amd64");
  CmdArgs.push_back(
      Args.MakeArgString("-L/usr/lib/gcc-lib/" + Triple + "/4.2.1"));
  CmdArgs.push_back(Args.MakeArgString("-L/usr/lib"));

  Args.AddAllArgs(CmdArgs, {options::OPT_L, options::OPT_T_Group,
                            options::OPT_e, options::OPT_s, options::OPT_t,
                            options::OPT_Z_Flag, options::OPT_r});

  bool NeedsSanitizerDeps = addSanitizerRuntimes(ToolChain, Args, CmdArgs);
  bool NeedsXRayDeps = addXRayRuntime(ToolChain, Args, CmdArgs);
  AddLinkerInputs(getToolChain(), Inputs, Args, CmdArgs, JA);

  if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs)) {
    if (D.CCCIsCXX()) {
      if (getToolChain().ShouldLinkCXXStdlib(Args))
        getToolChain().AddCXXStdlibLibArgs(Args, CmdArgs);
      if (Args.hasArg(options::OPT_pg))
        CmdArgs.push_back("-lm_p");
      else
        CmdArgs.push_back("-lm");
    }
    if (NeedsSanitizerDeps) {
//.........这里部分代码省略.........

static 
void ExecuteTemplightJobs(Driver &TheDriver, DiagnosticsEngine &Diags, 
    Compilation &C, Job &J, const char* Argv0,
    SmallVector<std::pair<int, const Command *>, 4>& FailingCommands) {
  if (JobList *jobs = dyn_cast<JobList>(&J)) {
    for (JobList::iterator it = jobs->begin(), it_end = jobs->end(); it != it_end; ++it)
      ExecuteTemplightJobs(TheDriver, Diags, C, *it, Argv0, FailingCommands);
    return;
  }
  
  Command *command = dyn_cast<Command>(&J);
  
  // Since argumentsFitWithinSystemLimits() may underestimate system's capacity
  // if the tool does not support response files, there is a chance/ that things
  // will just work without a response file, so we silently just skip it.
  if ( command && 
       command->getCreator().getResponseFilesSupport() != Tool::RF_None &&
       llvm::sys::argumentsFitWithinSystemLimits(command->getArguments()) ) {
    std::string TmpName = TheDriver.GetTemporaryPath("response", "txt");
    command->setResponseFile(C.addTempFile(C.getArgs().MakeArgString(
        TmpName.c_str())));
  }
  
  if ( command && (StringRef(command->getCreator().getName()) == "clang") ) {
    // Initialize a compiler invocation object from the clang (-cc1) arguments.
    const ArgStringList &cc_arguments = command->getArguments();
    const char** args_start = const_cast<const char**>(cc_arguments.data());
    const char** args_end = args_start + cc_arguments.size();
    
    std::unique_ptr<CompilerInstance> Clang(new CompilerInstance());
    
    int Res = !CompilerInvocation::CreateFromArgs(
        Clang->getInvocation(), args_start, args_end, Diags);
    if(Res)
      FailingCommands.push_back(std::make_pair(Res, command));
    
    Clang->getFrontendOpts().DisableFree = false;
    
    // Infer the builtin include path if unspecified.
    void *GetExecutablePathVP = (void *)(intptr_t) GetExecutablePath;
    if (Clang->getHeaderSearchOpts().UseBuiltinIncludes &&
        Clang->getHeaderSearchOpts().ResourceDir.empty())
      Clang->getHeaderSearchOpts().ResourceDir =
        CompilerInvocation::GetResourcesPath(Argv0, GetExecutablePathVP);
    
    // Create the compilers actual diagnostics engine.
    Clang->createDiagnostics();
    if (!Clang->hasDiagnostics()) {
      FailingCommands.push_back(std::make_pair(1, command));
      return;
    }
    
    LocalOutputFilename = ""; // Let the filename be created from options or output file name.
    std::string TemplightOutFile = TemplightAction::CreateOutputFilename(
      Clang.get(), "", InstProfiler, OutputToStdOut, MemoryProfile);
    // Check if templight filename is in a temporary path:
    llvm::SmallString<128> TDir;
    llvm::sys::path::system_temp_directory(true, TDir);
    if ( TDir.equals(llvm::sys::path::parent_path(llvm::StringRef(TemplightOutFile))) ) {
      C.addTempFile(TemplightOutFile.c_str());
      TempOutputFiles.push_back(TemplightOutFile);
    }
    
    // Execute the frontend actions.
    Res = ExecuteTemplightInvocation(Clang.get());
    if(Res)
      FailingCommands.push_back(std::make_pair(Res, command));
    
  } else {
    
    C.ExecuteJob(J, FailingCommands);
    
  }
  
}

void fuchsia::Linker::ConstructJob(Compilation &C, const JobAction &JA,
                                   const InputInfo &Output,
                                   const InputInfoList &Inputs,
                                   const ArgList &Args,
                                   const char *LinkingOutput) const {
  const toolchains::Fuchsia &ToolChain =
      static_cast<const toolchains::Fuchsia &>(getToolChain());
  const Driver &D = ToolChain.getDriver();

  ArgStringList CmdArgs;

  // Silence warning for "clang -g foo.o -o foo"
  Args.ClaimAllArgs(options::OPT_g_Group);
  // and "clang -emit-llvm foo.o -o foo"
  Args.ClaimAllArgs(options::OPT_emit_llvm);
  // and for "clang -w foo.o -o foo". Other warning options are already
  // handled somewhere else.
  Args.ClaimAllArgs(options::OPT_w);

  const char *Exec = Args.MakeArgString(ToolChain.GetLinkerPath());
  if (llvm::sys::path::stem(Exec).equals_lower("lld")) {
    CmdArgs.push_back("-flavor");
    CmdArgs.push_back("gnu");

    CmdArgs.push_back("-z");
    CmdArgs.push_back("rodynamic");
  }

  if (!D.SysRoot.empty())
    CmdArgs.push_back(Args.MakeArgString("--sysroot=" + D.SysRoot));

  if (!Args.hasArg(options::OPT_shared) && !Args.hasArg(options::OPT_r))
    CmdArgs.push_back("-pie");

  if (Args.hasArg(options::OPT_rdynamic))
    CmdArgs.push_back("-export-dynamic");

  if (Args.hasArg(options::OPT_s))
    CmdArgs.push_back("-s");

  if (Args.hasArg(options::OPT_r)) {
    CmdArgs.push_back("-r");
  } else {
    CmdArgs.push_back("--build-id");
    CmdArgs.push_back("--hash-style=gnu");
  }

  CmdArgs.push_back("--eh-frame-hdr");

  if (Args.hasArg(options::OPT_static))
    CmdArgs.push_back("-Bstatic");
  else if (Args.hasArg(options::OPT_shared))
    CmdArgs.push_back("-shared");

  if (!Args.hasArg(options::OPT_shared)) {
    std::string Dyld = D.DyldPrefix;
    if (ToolChain.getSanitizerArgs().needsAsanRt() &&
        ToolChain.getSanitizerArgs().needsSharedAsanRt())
      Dyld += "asan/";
    Dyld += "ld.so.1";
    CmdArgs.push_back("-dynamic-linker");
    CmdArgs.push_back(Args.MakeArgString(Dyld));
  }

  CmdArgs.push_back("-o");
  CmdArgs.push_back(Output.getFilename());

  if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nostartfiles)) {
    if (!Args.hasArg(options::OPT_shared)) {
      CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("Scrt1.o")));
    }
  }

  Args.AddAllArgs(CmdArgs, options::OPT_L);
  Args.AddAllArgs(CmdArgs, options::OPT_u);

  ToolChain.AddFilePathLibArgs(Args, CmdArgs);

  addSanitizerRuntimes(ToolChain, Args, CmdArgs);

  AddLinkerInputs(ToolChain, Inputs, Args, CmdArgs, JA);

  if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs)) {
    if (Args.hasArg(options::OPT_static))
      CmdArgs.push_back("-Bdynamic");

    if (D.CCCIsCXX()) {
      if (ToolChain.ShouldLinkCXXStdlib(Args))
        ToolChain.AddCXXStdlibLibArgs(Args, CmdArgs);
      CmdArgs.push_back("-lm");
    }

    AddRunTimeLibs(ToolChain, D, CmdArgs, Args);

    if (Args.hasArg(options::OPT_pthread) ||
        Args.hasArg(options::OPT_pthreads))
      CmdArgs.push_back("-lpthread");

    if (Args.hasArg(options::OPT_fsplit_stack))
      CmdArgs.push_back("--wrap=pthread_create");
//.........这里部分代码省略.........