xref: /external/clang/lib/Driver/Driver.cpp

//===--- Driver.cpp - Clang GCC Compatible Driver -------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#include "clang/Driver/Driver.h"
#include "InputInfo.h"
#include "ToolChains.h"
#include "clang/Basic/Version.h"
#include "clang/Config/config.h"
#include "clang/Driver/Action.h"
#include "clang/Driver/Compilation.h"
#include "clang/Driver/DriverDiagnostic.h"
#include "clang/Driver/Job.h"
#include "clang/Driver/Options.h"
#include "clang/Driver/Tool.h"
#include "clang/Driver/ToolChain.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/StringSet.h"
#include "llvm/ADT/StringSwitch.h"
#include "llvm/Option/Arg.h"
#include "llvm/Option/ArgList.h"
#include "llvm/Option/OptSpecifier.h"
#include "llvm/Option/OptTable.h"
#include "llvm/Option/Option.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/PrettyStackTrace.h"
#include "llvm/Support/Process.h"
#include "llvm/Support/Program.h"
#include "llvm/Support/raw_ostream.h"
#include <map>
#include <memory>

using namespace clang::driver;
using namespace clang;
using namespace llvm::opt;

Driver::Driver(StringRef ClangExecutable,
               StringRef DefaultTargetTriple,
               DiagnosticsEngine &Diags)
  : Opts(createDriverOptTable()), Diags(Diags), Mode(GCCMode),
    ClangExecutable(ClangExecutable), SysRoot(DEFAULT_SYSROOT),
    UseStdLib(true), DefaultTargetTriple(DefaultTargetTriple),
    DefaultImageName("a.out"),
    DriverTitle("clang LLVM compiler"),
    CCPrintOptionsFilename(nullptr), CCPrintHeadersFilename(nullptr),
    CCLogDiagnosticsFilename(nullptr),
    CCCPrintBindings(false),
    CCPrintHeaders(false), CCLogDiagnostics(false),
    CCGenDiagnostics(false), CCCGenericGCCName(""), CheckInputsExist(true),
    CCCUsePCH(true), SuppressMissingInputWarning(false) {

  Name = llvm::sys::path::stem(ClangExecutable);
  Dir  = llvm::sys::path::parent_path(ClangExecutable);

  // Compute the path to the resource directory.
  StringRef ClangResourceDir(CLANG_RESOURCE_DIR);
  SmallString<128> P(Dir);
  if (ClangResourceDir != "")
    llvm::sys::path::append(P, ClangResourceDir);
  else
    llvm::sys::path::append(P, "..", "lib", "clang", CLANG_VERSION_STRING);
  ResourceDir = P.str();
}

Driver::~Driver() {
  delete Opts;

  llvm::DeleteContainerSeconds(ToolChains);
}

void Driver::ParseDriverMode(ArrayRef<const char *> Args) {
  const std::string OptName =
    getOpts().getOption(options::OPT_driver_mode).getPrefixedName();

  for (size_t I = 0, E = Args.size(); I != E; ++I) {
    const StringRef Arg = Args[I];
    if (!Arg.startswith(OptName))
      continue;

    const StringRef Value = Arg.drop_front(OptName.size());
    const unsigned M = llvm::StringSwitch<unsigned>(Value)
        .Case("gcc", GCCMode)
        .Case("g++", GXXMode)
        .Case("cpp", CPPMode)
        .Case("cl",  CLMode)
        .Default(~0U);

    if (M != ~0U)
      Mode = static_cast<DriverMode>(M);
    else
      Diag(diag::err_drv_unsupported_option_argument) << OptName << Value;
  }
}

InputArgList *Driver::ParseArgStrings(ArrayRef<const char *> ArgList) {
  llvm::PrettyStackTraceString CrashInfo("Command line argument parsing");

  unsigned IncludedFlagsBitmask;
  unsigned ExcludedFlagsBitmask;
  std::tie(IncludedFlagsBitmask, ExcludedFlagsBitmask) =
    getIncludeExcludeOptionFlagMasks();

  unsigned MissingArgIndex, MissingArgCount;
  InputArgList *Args = getOpts().ParseArgs(ArgList.begin(), ArgList.end(),
                                           MissingArgIndex, MissingArgCount,
                                           IncludedFlagsBitmask,
                                           ExcludedFlagsBitmask);

  // Check for missing argument error.
  if (MissingArgCount)
    Diag(clang::diag::err_drv_missing_argument)
      << Args->getArgString(MissingArgIndex) << MissingArgCount;

  // Check for unsupported options.
  for (ArgList::const_iterator it = Args->begin(), ie = Args->end();
       it != ie; ++it) {
    Arg *A = *it;
    if (A->getOption().hasFlag(options::Unsupported)) {
      Diag(clang::diag::err_drv_unsupported_opt) << A->getAsString(*Args);
      continue;
    }

    // Warn about -mcpu= without an argument.
    if (A->getOption().matches(options::OPT_mcpu_EQ) &&
        A->containsValue("")) {
      Diag(clang::diag::warn_drv_empty_joined_argument) <<
        A->getAsString(*Args);
    }
  }

  for (arg_iterator it = Args->filtered_begin(options::OPT_UNKNOWN),
         ie = Args->filtered_end(); it != ie; ++it) {
    Diags.Report(diag::err_drv_unknown_argument) << (*it) ->getAsString(*Args);
  }

  return Args;
}

// Determine which compilation mode we are in. We look for options which
// affect the phase, starting with the earliest phases, and record which
// option we used to determine the final phase.
phases::ID Driver::getFinalPhase(const DerivedArgList &DAL, Arg **FinalPhaseArg)
const {
  Arg *PhaseArg = nullptr;
  phases::ID FinalPhase;

  // -{E,EP,P,M,MM} only run the preprocessor.
  if (CCCIsCPP() ||
      (PhaseArg = DAL.getLastArg(options::OPT_E)) ||
      (PhaseArg = DAL.getLastArg(options::OPT__SLASH_EP)) ||
      (PhaseArg = DAL.getLastArg(options::OPT_M, options::OPT_MM)) ||
      (PhaseArg = DAL.getLastArg(options::OPT__SLASH_P))) {
    FinalPhase = phases::Preprocess;

    // -{fsyntax-only,-analyze,emit-ast,S} only run up to the compiler.
  } else if ((PhaseArg = DAL.getLastArg(options::OPT_fsyntax_only)) ||
             (PhaseArg = DAL.getLastArg(options::OPT_module_file_info)) ||
             (PhaseArg = DAL.getLastArg(options::OPT_verify_pch)) ||
             (PhaseArg = DAL.getLastArg(options::OPT_rewrite_objc)) ||
             (PhaseArg = DAL.getLastArg(options::OPT_rewrite_legacy_objc)) ||
             (PhaseArg = DAL.getLastArg(options::OPT__migrate)) ||
             (PhaseArg = DAL.getLastArg(options::OPT__analyze,
                                        options::OPT__analyze_auto)) ||
             (PhaseArg = DAL.getLastArg(options::OPT_emit_ast)) ||
             (PhaseArg = DAL.getLastArg(options::OPT_S))) {
    FinalPhase = phases::Compile;

    // -c only runs up to the assembler.
  } else if ((PhaseArg = DAL.getLastArg(options::OPT_c))) {
    FinalPhase = phases::Assemble;

    // Otherwise do everything.
  } else
    FinalPhase = phases::Link;

  if (FinalPhaseArg)
    *FinalPhaseArg = PhaseArg;

  return FinalPhase;
}

static Arg* MakeInputArg(DerivedArgList &Args, OptTable *Opts,
                         StringRef Value) {
  Arg *A = new Arg(Opts->getOption(options::OPT_INPUT), Value,
                   Args.getBaseArgs().MakeIndex(Value), Value.data());
  Args.AddSynthesizedArg(A);
  A->claim();
  return A;
}

DerivedArgList *Driver::TranslateInputArgs(const InputArgList &Args) const {
  DerivedArgList *DAL = new DerivedArgList(Args);

  bool HasNostdlib = Args.hasArg(options::OPT_nostdlib);
  for (ArgList::const_iterator it = Args.begin(),
         ie = Args.end(); it != ie; ++it) {
    const Arg *A = *it;

    // Unfortunately, we have to parse some forwarding options (-Xassembler,
    // -Xlinker, -Xpreprocessor) because we either integrate their functionality
    // (assembler and preprocessor), or bypass a previous driver ('collect2').

    // Rewrite linker options, to replace --no-demangle with a custom internal
    // option.
    if ((A->getOption().matches(options::OPT_Wl_COMMA) ||
         A->getOption().matches(options::OPT_Xlinker)) &&
        A->containsValue("--no-demangle")) {
      // Add the rewritten no-demangle argument.
      DAL->AddFlagArg(A, Opts->getOption(options::OPT_Z_Xlinker__no_demangle));

      // Add the remaining values as Xlinker arguments.
      for (unsigned i = 0, e = A->getNumValues(); i != e; ++i)
        if (StringRef(A->getValue(i)) != "--no-demangle")
          DAL->AddSeparateArg(A, Opts->getOption(options::OPT_Xlinker),
                              A->getValue(i));

      continue;
    }

    // Rewrite preprocessor options, to replace -Wp,-MD,FOO which is used by
    // some build systems. We don't try to be complete here because we don't
    // care to encourage this usage model.
    if (A->getOption().matches(options::OPT_Wp_COMMA) &&
        (A->getValue(0) == StringRef("-MD") ||
         A->getValue(0) == StringRef("-MMD"))) {
      // Rewrite to -MD/-MMD along with -MF.
      if (A->getValue(0) == StringRef("-MD"))
        DAL->AddFlagArg(A, Opts->getOption(options::OPT_MD));
      else
        DAL->AddFlagArg(A, Opts->getOption(options::OPT_MMD));
      if (A->getNumValues() == 2)
        DAL->AddSeparateArg(A, Opts->getOption(options::OPT_MF),
                            A->getValue(1));
      continue;
    }

    // Rewrite reserved library names.
    if (A->getOption().matches(options::OPT_l)) {
      StringRef Value = A->getValue();

      // Rewrite unless -nostdlib is present.
      if (!HasNostdlib && Value == "stdc++") {
        DAL->AddFlagArg(A, Opts->getOption(
                              options::OPT_Z_reserved_lib_stdcxx));
        continue;
      }

      // Rewrite unconditionally.
      if (Value == "cc_kext") {
        DAL->AddFlagArg(A, Opts->getOption(
                              options::OPT_Z_reserved_lib_cckext));
        continue;
      }
    }

    // Pick up inputs via the -- option.
    if (A->getOption().matches(options::OPT__DASH_DASH)) {
      A->claim();
      for (unsigned i = 0, e = A->getNumValues(); i != e; ++i)
        DAL->append(MakeInputArg(*DAL, Opts, A->getValue(i)));
      continue;
    }

    DAL->append(*it);
  }

  // Add a default value of -mlinker-version=, if one was given and the user
  // didn't specify one.
#if defined(HOST_LINK_VERSION)
  if (!Args.hasArg(options::OPT_mlinker_version_EQ)) {
    DAL->AddJoinedArg(0, Opts->getOption(options::OPT_mlinker_version_EQ),
                      HOST_LINK_VERSION);
    DAL->getLastArg(options::OPT_mlinker_version_EQ)->claim();
  }
#endif

  return DAL;
}

Compilation *Driver::BuildCompilation(ArrayRef<const char *> ArgList) {
  llvm::PrettyStackTraceString CrashInfo("Compilation construction");

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

  if (char *env = ::getenv("COMPILER_PATH")) {
    StringRef CompilerPath = env;
    while (!CompilerPath.empty()) {
      std::pair<StringRef, StringRef> Split
        = CompilerPath.split(llvm::sys::EnvPathSeparator);
      PrefixDirs.push_back(Split.first);
      CompilerPath = Split.second;
    }
  }

  // We look for the driver mode option early, because the mode can affect
  // how other options are parsed.
  ParseDriverMode(ArgList.slice(1));

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

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

  InputArgList *Args = ParseArgStrings(ArgList.slice(1));

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

  // Ignore -pipe.
  Args->ClaimAllArgs(options::OPT_pipe);

  // 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.
  CCCPrintActions = Args->hasArg(options::OPT_ccc_print_phases);
  CCCPrintBindings = Args->hasArg(options::OPT_ccc_print_bindings);
  if (const Arg *A = Args->getLastArg(options::OPT_ccc_gcc_name))
    CCCGenericGCCName = A->getValue();
  CCCUsePCH = Args->hasFlag(options::OPT_ccc_pch_is_pch,
                            options::OPT_ccc_pch_is_pth);
  // FIXME: DefaultTargetTriple is used by the target-prefixed calls to as/ld
  // and getToolChain is const.
  if (IsCLMode()) {
    // clang-cl targets MSVC-style Win32.
    llvm::Triple T(DefaultTargetTriple);
    T.setOS(llvm::Triple::Win32);
    T.setEnvironment(llvm::Triple::MSVC);
    DefaultTargetTriple = T.str();
  }
  if (const Arg *A = Args->getLastArg(options::OPT_target))
    DefaultTargetTriple = A->getValue();
  if (const Arg *A = Args->getLastArg(options::OPT_ccc_install_dir))
    Dir = InstalledDir = A->getValue();
  for (arg_iterator it = Args->filtered_begin(options::OPT_B),
         ie = Args->filtered_end(); it != ie; ++it) {
    const Arg *A = *it;
    A->claim();
    PrefixDirs.push_back(A->getValue(0));
  }
  if (const Arg *A = Args->getLastArg(options::OPT__sysroot_EQ))
    SysRoot = A->getValue();
  if (const Arg *A = Args->getLastArg(options::OPT__dyld_prefix_EQ))
    DyldPrefix = A->getValue();
  if (Args->hasArg(options::OPT_nostdlib))
    UseStdLib = false;

  if (const Arg *A = Args->getLastArg(options::OPT_resource_dir))
    ResourceDir = A->getValue();

  // Perform the default argument translations.
  DerivedArgList *TranslatedArgs = TranslateInputArgs(*Args);

  // Owned by the host.
  const ToolChain &TC = getToolChain(*Args);

  // The compilation takes ownership of Args.
  Compilation *C = new Compilation(*this, TC, Args, TranslatedArgs);

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

  // Construct the list of inputs.
  InputList Inputs;
  BuildInputs(C->getDefaultToolChain(), *TranslatedArgs, Inputs);

  // Construct the list of abstract actions to perform for this compilation. On
  // MachO targets this uses the driver-driver and universal actions.
  if (TC.getTriple().isOSBinFormatMachO())
    BuildUniversalActions(C->getDefaultToolChain(), C->getArgs(),
                          Inputs, C->getActions());
  else
    BuildActions(C->getDefaultToolChain(), C->getArgs(), Inputs,
                 C->getActions());

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

  BuildJobs(*C);

  return C;
}

// When clang crashes, produce diagnostic information including the fully
// preprocessed source file(s).  Request that the developer attach the
// diagnostic information to a bug report.
void Driver::generateCompilationDiagnostics(Compilation &C,
                                            const Command *FailingCommand) {
  if (C.getArgs().hasArg(options::OPT_fno_crash_diagnostics))
    return;

  // Don't try to generate diagnostics for link or dsymutil jobs.
  if (FailingCommand && (FailingCommand->getCreator().isLinkJob() ||
                         FailingCommand->getCreator().isDsymutilJob()))
    return;

  // Print the version of the compiler.
  PrintVersion(C, llvm::errs());

  Diag(clang::diag::note_drv_command_failed_diag_msg)
    << "PLEASE submit a bug report to " BUG_REPORT_URL " and include the "
    "crash backtrace, preprocessed source, and associated run script.";

  // Suppress driver output and emit preprocessor output to temp file.
  Mode = CPPMode;
  CCGenDiagnostics = true;

  // Save the original job command(s).
  std::string Cmd;
  llvm::raw_string_ostream OS(Cmd);
  if (FailingCommand)
    FailingCommand->Print(OS, "\n", /*Quote*/ false, /*CrashReport*/ true);
  else
    // Crash triggered by FORCE_CLANG_DIAGNOSTICS_CRASH, which doesn't have an
    // associated FailingCommand, so just pass all jobs.
    C.getJobs().Print(OS, "\n", /*Quote*/ false, /*CrashReport*/ true);
  OS.flush();

  // Keep track of whether we produce any errors while trying to produce
  // preprocessed sources.
  DiagnosticErrorTrap Trap(Diags);

  // Suppress tool output.
  C.initCompilationForDiagnostics();

  // Construct the list of inputs.
  InputList Inputs;
  BuildInputs(C.getDefaultToolChain(), C.getArgs(), Inputs);

  for (InputList::iterator it = Inputs.begin(), ie = Inputs.end(); it != ie;) {
    bool IgnoreInput = false;

    // Ignore input from stdin or any inputs that cannot be preprocessed.
    // Check type first as not all linker inputs have a value.
   if (types::getPreprocessedType(it->first) == types::TY_INVALID) {
      IgnoreInput = true;
    } else if (!strcmp(it->second->getValue(), "-")) {
      Diag(clang::diag::note_drv_command_failed_diag_msg)
        << "Error generating preprocessed source(s) - ignoring input from stdin"
        ".";
      IgnoreInput = true;
    }

    if (IgnoreInput) {
      it = Inputs.erase(it);
      ie = Inputs.end();
    } else {
      ++it;
    }
  }

  if (Inputs.empty()) {
    Diag(clang::diag::note_drv_command_failed_diag_msg)
      << "Error generating preprocessed source(s) - no preprocessable inputs.";
    return;
  }

  // Don't attempt to generate preprocessed files if multiple -arch options are
  // used, unless they're all duplicates.
  llvm::StringSet<> ArchNames;
  for (ArgList::const_iterator it = C.getArgs().begin(), ie = C.getArgs().end();
       it != ie; ++it) {
    Arg *A = *it;
    if (A->getOption().matches(options::OPT_arch)) {
      StringRef ArchName = A->getValue();
      ArchNames.insert(ArchName);
    }
  }
  if (ArchNames.size() > 1) {
    Diag(clang::diag::note_drv_command_failed_diag_msg)
      << "Error generating preprocessed source(s) - cannot generate "
      "preprocessed source with multiple -arch options.";
    return;
  }

  // Construct the list of abstract actions to perform for this compilation. On
  // Darwin OSes this uses the driver-driver and builds universal actions.
  const ToolChain &TC = C.getDefaultToolChain();
  if (TC.getTriple().isOSBinFormatMachO())
    BuildUniversalActions(TC, C.getArgs(), Inputs, C.getActions());
  else
    BuildActions(TC, C.getArgs(), Inputs, C.getActions());

  BuildJobs(C);

  // If there were errors building the compilation, quit now.
  if (Trap.hasErrorOccurred()) {
    Diag(clang::diag::note_drv_command_failed_diag_msg)
      << "Error generating preprocessed source(s).";
    return;
  }

  // Generate preprocessed output.
  SmallVector<std::pair<int, const Command *>, 4> FailingCommands;
  C.ExecuteJob(C.getJobs(), FailingCommands);

  // If the command succeeded, we are done.
  if (FailingCommands.empty()) {
    Diag(clang::diag::note_drv_command_failed_diag_msg)
      << "\n********************\n\n"
      "PLEASE ATTACH THE FOLLOWING FILES TO THE BUG REPORT:\n"
      "Preprocessed source(s) and associated run script(s) are located at:";
    ArgStringList Files = C.getTempFiles();
    for (ArgStringList::const_iterator it = Files.begin(), ie = Files.end();
         it != ie; ++it) {
      Diag(clang::diag::note_drv_command_failed_diag_msg) << *it;
      std::string Script = StringRef(*it).rsplit('.').first;
      // In some cases (modules) we'll dump extra data to help with reproducing
      // the crash into a directory next to the output.
      SmallString<128> VFS;
      if (llvm::sys::fs::exists(Script + ".cache")) {
        Diag(clang::diag::note_drv_command_failed_diag_msg)
            << Script + ".cache";
        VFS = llvm::sys::path::filename(Script + ".cache");
        llvm::sys::path::append(VFS, "vfs", "vfs.yaml");
      }

      std::string Err;
      Script += ".sh";
      llvm::raw_fd_ostream ScriptOS(Script.c_str(), Err, llvm::sys::fs::F_Excl);
      if (!Err.empty()) {
        Diag(clang::diag::note_drv_command_failed_diag_msg)
          << "Error generating run script: " + Script + " " + Err;
      } else {
        // Replace the original filename with the preprocessed one.
        size_t I, E;
        I = Cmd.find("-main-file-name ");
        assert (I != std::string::npos && "Expected to find -main-file-name");
        I += 16;
        E = Cmd.find(" ", I);
        assert (E != std::string::npos && "-main-file-name missing argument?");
        StringRef OldFilename = StringRef(Cmd).slice(I, E);
        StringRef NewFilename = llvm::sys::path::filename(*it);
        I = StringRef(Cmd).rfind(OldFilename);
        E = I + OldFilename.size();
        I = Cmd.rfind(" ", I) + 1;
        Cmd.replace(I, E - I, NewFilename.data(), NewFilename.size());
        if (!VFS.empty()) {
          // Add the VFS overlay to the reproduction script.
          I += NewFilename.size();
          Cmd.insert(I, std::string(" -ivfsoverlay ") + VFS.c_str());
        }
        ScriptOS << Cmd;
        Diag(clang::diag::note_drv_command_failed_diag_msg) << Script;
      }
    }
    Diag(clang::diag::note_drv_command_failed_diag_msg)
      << "\n\n********************";
  } else {
    // Failure, remove preprocessed files.
    if (!C.getArgs().hasArg(options::OPT_save_temps))
      C.CleanupFileList(C.getTempFiles(), true);

    Diag(clang::diag::note_drv_command_failed_diag_msg)
      << "Error generating preprocessed source(s).";
  }
}

int Driver::ExecuteCompilation(const Compilation &C,
    SmallVectorImpl< std::pair<int, const Command *> > &FailingCommands) const {
  // Just print if -### was present.
  if (C.getArgs().hasArg(options::OPT__HASH_HASH_HASH)) {
    C.getJobs().Print(llvm::errs(), "\n", true);
    return 0;
  }

  // If there were errors building the compilation, quit now.
  if (Diags.hasErrorOccurred())
    return 1;

  C.ExecuteJob(C.getJobs(), FailingCommands);

  // Remove temp files.
  C.CleanupFileList(C.getTempFiles());

  // If the command succeeded, we are done.
  if (FailingCommands.empty())
    return 0;

  // Otherwise, remove result files and print extra information about abnormal
  // failures.
  for (SmallVectorImpl< std::pair<int, const Command *> >::iterator it =
         FailingCommands.begin(), ie = FailingCommands.end(); it != ie; ++it) {
    int Res = it->first;
    const Command *FailingCommand = it->second;

    // Remove result files if we're not saving temps.
    if (!C.getArgs().hasArg(options::OPT_save_temps)) {
      const JobAction *JA = cast<JobAction>(&FailingCommand->getSource());
      C.CleanupFileMap(C.getResultFiles(), JA, true);

      // Failure result files are valid unless we crashed.
      if (Res < 0)
        C.CleanupFileMap(C.getFailureResultFiles(), JA, true);
    }

    // Print extra information about abnormal failures, if possible.
    //
    // This is ad-hoc, but we don't want to be excessively noisy. If the result
    // status was 1, assume the command failed normally. In particular, if it
    // was the compiler then assume it gave a reasonable error code. Failures
    // in other tools are less common, and they generally have worse
    // diagnostics, so always print the diagnostic there.
    const Tool &FailingTool = FailingCommand->getCreator();

    if (!FailingCommand->getCreator().hasGoodDiagnostics() || Res != 1) {
      // FIXME: See FIXME above regarding result code interpretation.
      if (Res < 0)
        Diag(clang::diag::err_drv_command_signalled)
          << FailingTool.getShortName();
      else
        Diag(clang::diag::err_drv_command_failed)
          << FailingTool.getShortName() << Res;
    }
  }
  return 0;
}

void Driver::PrintHelp(bool ShowHidden) const {
  unsigned IncludedFlagsBitmask;
  unsigned ExcludedFlagsBitmask;
  std::tie(IncludedFlagsBitmask, ExcludedFlagsBitmask) =
    getIncludeExcludeOptionFlagMasks();

  ExcludedFlagsBitmask |= options::NoDriverOption;
  if (!ShowHidden)
    ExcludedFlagsBitmask |= HelpHidden;

  getOpts().PrintHelp(llvm::outs(), Name.c_str(), DriverTitle.c_str(),
                      IncludedFlagsBitmask, ExcludedFlagsBitmask);
}

void Driver::PrintVersion(const Compilation &C, raw_ostream &OS) const {
  // FIXME: The following handlers should use a callback mechanism, we don't
  // know what the client would like to do.
  OS << getClangFullVersion() << '\n';
  const ToolChain &TC = C.getDefaultToolChain();
  OS << "Target: " << TC.getTripleString() << '\n';

  // Print the threading model.
  //
  // FIXME: Implement correctly.
  OS << "Thread model: " << "posix" << '\n';
}

/// PrintDiagnosticCategories - Implement the --print-diagnostic-categories
/// option.
static void PrintDiagnosticCategories(raw_ostream &OS) {
  // Skip the empty category.
  for (unsigned i = 1, max = DiagnosticIDs::getNumberOfCategories();
       i != max; ++i)
    OS << i << ',' << DiagnosticIDs::getCategoryNameFromID(i) << '\n';
}

bool Driver::HandleImmediateArgs(const Compilation &C) {
  // The order these options are handled in gcc is all over the place, but we
  // don't expect inconsistencies w.r.t. that to matter in practice.

  if (C.getArgs().hasArg(options::OPT_dumpmachine)) {
    llvm::outs() << C.getDefaultToolChain().getTripleString() << '\n';
    return false;
  }

  if (C.getArgs().hasArg(options::OPT_dumpversion)) {
    // Since -dumpversion is only implemented for pedantic GCC compatibility, we
    // return an answer which matches our definition of __VERSION__.
    //
    // If we want to return a more correct answer some day, then we should
    // introduce a non-pedantically GCC compatible mode to Clang in which we
    // provide sensible definitions for -dumpversion, __VERSION__, etc.
    llvm::outs() << "4.2.1\n";
    return false;
  }

  if (C.getArgs().hasArg(options::OPT__print_diagnostic_categories)) {
    PrintDiagnosticCategories(llvm::outs());
    return false;
  }

  if (C.getArgs().hasArg(options::OPT_help) ||
      C.getArgs().hasArg(options::OPT__help_hidden)) {
    PrintHelp(C.getArgs().hasArg(options::OPT__help_hidden));
    return false;
  }

  if (C.getArgs().hasArg(options::OPT__version)) {
    // Follow gcc behavior and use stdout for --version and stderr for -v.
    PrintVersion(C, llvm::outs());
    return false;
  }

  if (C.getArgs().hasArg(options::OPT_v) ||
      C.getArgs().hasArg(options::OPT__HASH_HASH_HASH)) {
    PrintVersion(C, llvm::errs());
    SuppressMissingInputWarning = true;
  }

  const ToolChain &TC = C.getDefaultToolChain();

  if (C.getArgs().hasArg(options::OPT_v))
    TC.printVerboseInfo(llvm::errs());

  if (C.getArgs().hasArg(options::OPT_print_search_dirs)) {
    llvm::outs() << "programs: =";
    for (ToolChain::path_list::const_iterator it = TC.getProgramPaths().begin(),
           ie = TC.getProgramPaths().end(); it != ie; ++it) {
      if (it != TC.getProgramPaths().begin())
        llvm::outs() << ':';
      llvm::outs() << *it;
    }
    llvm::outs() << "\n";
    llvm::outs() << "libraries: =" << ResourceDir;

    StringRef sysroot = C.getSysRoot();

    for (ToolChain::path_list::const_iterator it = TC.getFilePaths().begin(),
           ie = TC.getFilePaths().end(); it != ie; ++it) {
      llvm::outs() << ':';
      const char *path = it->c_str();
      if (path[0] == '=')
        llvm::outs() << sysroot << path + 1;
      else
        llvm::outs() << path;
    }
    llvm::outs() << "\n";
    return false;
  }

  // FIXME: The following handlers should use a callback mechanism, we don't
  // know what the client would like to do.
  if (Arg *A = C.getArgs().getLastArg(options::OPT_print_file_name_EQ)) {
    llvm::outs() << GetFilePath(A->getValue(), TC) << "\n";
    return false;
  }

  if (Arg *A = C.getArgs().getLastArg(options::OPT_print_prog_name_EQ)) {
    llvm::outs() << GetProgramPath(A->getValue(), TC) << "\n";
    return false;
  }

  if (C.getArgs().hasArg(options::OPT_print_libgcc_file_name)) {
    llvm::outs() << GetFilePath("libgcc.a", TC) << "\n";
    return false;
  }

  if (C.getArgs().hasArg(options::OPT_print_multi_lib)) {
    const MultilibSet &Multilibs = TC.getMultilibs();

    for (MultilibSet::const_iterator I = Multilibs.begin(), E = Multilibs.end();
         I != E; ++I) {
      llvm::outs() << *I << "\n";
    }
    return false;
  }

  if (C.getArgs().hasArg(options::OPT_print_multi_directory)) {
    const MultilibSet &Multilibs = TC.getMultilibs();
    for (MultilibSet::const_iterator I = Multilibs.begin(), E = Multilibs.end();
         I != E; ++I) {
      if (I->gccSuffix().empty())
        llvm::