//===-- cc1as_main.cpp - Clang Assembler  ---------------------------------===//

//

// 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

//

//===----------------------------------------------------------------------===//

//

// This is the entry point to the clang -cc1as functionality, which implements

// the direct interface to the LLVM MC based assembler.

//

//===----------------------------------------------------------------------===//

#include "clang/Basic/Diagnostic.h"

#include "clang/Basic/DiagnosticOptions.h"

#include "clang/Driver/DriverDiagnostic.h"

#include "clang/Driver/Options.h"

#include "clang/Frontend/FrontendDiagnostic.h"

#include "clang/Frontend/TextDiagnosticPrinter.h"

#include "clang/Frontend/Utils.h"

#include "llvm/ADT/STLExtras.h"

#include "llvm/ADT/StringSwitch.h"

#include "llvm/ADT/Triple.h"

#include "llvm/IR/DataLayout.h"

#include "llvm/MC/MCAsmBackend.h"

#include "llvm/MC/MCAsmInfo.h"

#include "llvm/MC/MCCodeEmitter.h"

#include "llvm/MC/MCContext.h"

#include "llvm/MC/MCInstrInfo.h"

#include "llvm/MC/MCObjectFileInfo.h"

#include "llvm/MC/MCObjectWriter.h"

#include "llvm/MC/MCParser/MCAsmParser.h"

#include "llvm/MC/MCParser/MCTargetAsmParser.h"

#include "llvm/MC/MCRegisterInfo.h"

#include "llvm/MC/MCSectionMachO.h"

#include "llvm/MC/MCStreamer.h"

#include "llvm/MC/MCSubtargetInfo.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/Support/CommandLine.h"

#include "llvm/Support/ErrorHandling.h"

#include "llvm/Support/FileSystem.h"

#include "llvm/Support/FormattedStream.h"

#include "llvm/Support/Host.h"

#include "llvm/Support/MemoryBuffer.h"

#include "llvm/Support/Path.h"

#include "llvm/Support/Process.h"

#include "llvm/Support/Signals.h"

#include "llvm/Support/SourceMgr.h"

#include "llvm/Support/TargetSelect.h"

#include "llvm/Support/Timer.h"

#include "llvm/Support/raw_ostream.h"

#include <memory>

#include <system_error>

using namespace clang;

using namespace clang::driver;

using namespace clang::driver::options;

using namespace llvm;

using namespace llvm::opt;

namespace {

/// Helper class for representing a single invocation of the assembler.

struct AssemblerInvocation {

  /// @name Target Options

  /// @{

  /// The name of the target triple to assemble for.

  std::string Triple;

  /// If given, the name of the target CPU to determine which instructions

  /// are legal.

  std::string CPU;

  /// The list of target specific features to enable or disable -- this should

  /// be a list of strings starting with '+' or '-'.

  std::vector<std::string> Features;

  /// The list of symbol definitions.

  std::vector<std::string> SymbolDefs;

  /// @}

  /// @name Language Options

  /// @{

  std::vector<std::string> IncludePaths;

  unsigned NoInitialTextSection : 1;

  unsigned SaveTemporaryLabels : 1;

  unsigned GenDwarfForAssembly : 1;

  unsigned RelaxELFRelocations : 1;

  unsigned Dwarf64 : 1;

  unsigned DwarfVersion;

  std::string DwarfDebugFlags;

  std::string DwarfDebugProducer;

  std::string DebugCompilationDir;

  std::map<const std::string, const std::string> DebugPrefixMap;

  llvm::DebugCompressionType CompressDebugSections =

      llvm::DebugCompressionType::None;

  std::string MainFileName;

  std::string SplitDwarfOutput;

  /// @}

  /// @name Frontend Options

  /// @{

  std::string InputFile;

  std::vector<std::string> LLVMArgs;

  std::string OutputPath;

  enum FileType {

    FT_Asm,  ///< Assembly (.s) output, transliterate mode.

    FT_Null, ///< No output, for timing purposes.

    FT_Obj   ///< Object file output.

  };

  FileType OutputType;

  unsigned ShowHelp : 1;

  unsigned ShowVersion : 1;

  /// @}

  /// @name Transliterate Options

  /// @{

  unsigned OutputAsmVariant;

  unsigned ShowEncoding : 1;

  unsigned ShowInst : 1;

  /// @}

  /// @name Assembler Options

  /// @{

  unsigned RelaxAll : 1;

  unsigned NoExecStack : 1;

  unsigned FatalWarnings : 1;

  unsigned NoWarn : 1;

  unsigned IncrementalLinkerCompatible : 1;

  unsigned EmbedBitcode : 1;

  /// Whether to emit DWARF unwind info.

  EmitDwarfUnwindType EmitDwarfUnwind;

  /// The name of the relocation model to use.

  std::string RelocationModel;

  /// The ABI targeted by the backend. Specified using -target-abi. Empty

  /// otherwise.

  std::string TargetABI;

  /// Darwin target variant triple, the variant of the deployment target

  /// for which the code is being compiled.

  llvm::Optional<llvm::Triple> DarwinTargetVariantTriple;

  /// @}

public:

  AssemblerInvocation() {

    Triple = "";

    NoInitialTextSection = 0;

    InputFile = "-";

    OutputPath = "-";

    OutputType = FT_Asm;

    OutputAsmVariant = 0;

    ShowInst = 0;

    ShowEncoding = 0;

    RelaxAll = 0;

    NoExecStack = 0;

    FatalWarnings = 0;

    NoWarn = 0;

    IncrementalLinkerCompatible = 0;

    Dwarf64 = 0;

    DwarfVersion = 0;

    EmbedBitcode = 0;

    EmitDwarfUnwind = EmitDwarfUnwindType::Default;

  }

  static bool CreateFromArgs(AssemblerInvocation &Res,

                             ArrayRef<const char *> Argv,

                             DiagnosticsEngine &Diags);

};

}

bool AssemblerInvocation::CreateFromArgs(AssemblerInvocation &Opts,

                                         ArrayRef<const char *> Argv,

                                         DiagnosticsEngine &Diags) {

  bool Success = true;

  // Parse the arguments.

  const OptTable &OptTbl = getDriverOptTable();

  const unsigned IncludedFlagsBitmask = options::CC1AsOption;

  unsigned MissingArgIndex, MissingArgCount;

  InputArgList Args = OptTbl.ParseArgs(Argv, MissingArgIndex, MissingArgCount,

                                       IncludedFlagsBitmask);

  // Check for missing argument error.

  if (MissingArgCount) {

    Diags.Report(diag::err_drv_missing_argument)

        << Args.getArgString(MissingArgIndex) << MissingArgCount;

    Success = false;

  }

  // Issue errors on unknown arguments.

  for (const Arg *A : Args.filtered(OPT_UNKNOWN)) {

    auto ArgString = A->getAsString(Args);

    std::string Nearest;

    if (OptTbl.findNearest(ArgString, Nearest, IncludedFlagsBitmask) > 1)

      Diags.Report(diag::err_drv_unknown_argument) << ArgString;

    else

      Diags.Report(diag::err_drv_unknown_argument_with_suggestion)

          << ArgString << Nearest;

    Success = false;

  }

  // Construct the invocation.

  // Target Options

  Opts.Triple = llvm::Triple::normalize(Args.getLastArgValue(OPT_triple));

  if (Arg *A = Args.getLastArg(options::OPT_darwin_target_variant_triple))

    Opts.DarwinTargetVariantTriple = llvm::Triple(A->getValue());

  Opts.CPU = std::string(Args.getLastArgValue(OPT_target_cpu));

  Opts.Features = Args.getAllArgValues(OPT_target_feature);

  // Use the default target triple if unspecified.

  if (Opts.Triple.empty())

    Opts.Triple = llvm::sys::getDefaultTargetTriple();

  // Language Options

  Opts.IncludePaths = Args.getAllArgValues(OPT_I);

  Opts.NoInitialTextSection = Args.hasArg(OPT_n);

  Opts.SaveTemporaryLabels = Args.hasArg(OPT_msave_temp_labels);

  // Any DebugInfoKind implies GenDwarfForAssembly.

  Opts.GenDwarfForAssembly = Args.hasArg(OPT_debug_info_kind_EQ);

  if (const Arg *A = Args.getLastArg(OPT_compress_debug_sections_EQ)) {

    Opts.CompressDebugSections =

        llvm::StringSwitch<llvm::DebugCompressionType>(A->getValue())

            .Case("none", llvm::DebugCompressionType::None)

            .Case("zlib", llvm::DebugCompressionType::Z)

            .Default(llvm::DebugCompressionType::None);

  }

  Opts.RelaxELFRelocations = Args.hasArg(OPT_mrelax_relocations);

  if (auto *DwarfFormatArg = Args.getLastArg(OPT_gdwarf64, OPT_gdwarf32))

    Opts.Dwarf64 = DwarfFormatArg->getOption().matches(OPT_gdwarf64);

  Opts.DwarfVersion = getLastArgIntValue(Args, OPT_dwarf_version_EQ, 2, Diags);

  Opts.DwarfDebugFlags =

      std::string(Args.getLastArgValue(OPT_dwarf_debug_flags));

  Opts.DwarfDebugProducer =

      std::string(Args.getLastArgValue(OPT_dwarf_debug_producer));

  if (const Arg *A = Args.getLastArg(options::OPT_ffile_compilation_dir_EQ,

                                     options::OPT_fdebug_compilation_dir_EQ))

    Opts.DebugCompilationDir = A->getValue();

  Opts.MainFileName = std::string(Args.getLastArgValue(OPT_main_file_name));

  for (const auto &Arg : Args.getAllArgValues(OPT_fdebug_prefix_map_EQ)) {

    auto Split = StringRef(Arg).split('=');

    Opts.DebugPrefixMap.insert(

        {std::string(Split.first), std::string(Split.second)});

  }

  // Frontend Options

  if (Args.hasArg(OPT_INPUT)) {

    bool First = true;

    for (const Arg *A : Args.filtered(OPT_INPUT)) {

      if (First) {

        Opts.InputFile = A->getValue();

        First = false;

      } else {

        Diags.Report(diag::err_drv_unknown_argument) << A->getAsString(Args);

        Success = false;

      }

    }

  }

  Opts.LLVMArgs = Args.getAllArgValues(OPT_mllvm);

  Opts.OutputPath = std::string(Args.getLastArgValue(OPT_o));

  Opts.SplitDwarfOutput =

      std::string(Args.getLastArgValue(OPT_split_dwarf_output));

  if (Arg *A = Args.getLastArg(OPT_filetype)) {

    StringRef Name = A->getValue();

    unsigned OutputType = StringSwitch<unsigned>(Name)

      .Case("asm", FT_Asm)

      .Case("null", FT_Null)

      .Case("obj", FT_Obj)

      .Default(~0U);

    if (OutputType == ~0U) {

      Diags.Report(diag::err_drv_invalid_value) << A->getAsString(Args) << Name;

      Success = false;

    } else

      Opts.OutputType = FileType(OutputType);

  }

  Opts.ShowHelp = Args.hasArg(OPT_help);

  Opts.ShowVersion = Args.hasArg(OPT_version);

  // Transliterate Options

  Opts.OutputAsmVariant =

      getLastArgIntValue(Args, OPT_output_asm_variant, 0, Diags);

  Opts.ShowEncoding = Args.hasArg(OPT_show_encoding);

  Opts.ShowInst = Args.hasArg(OPT_show_inst);

  // Assemble Options

  Opts.RelaxAll = Args.hasArg(OPT_mrelax_all);

  Opts.NoExecStack = Args.hasArg(OPT_mno_exec_stack);

  Opts.FatalWarnings = Args.hasArg(OPT_massembler_fatal_warnings);

  Opts.NoWarn = Args.hasArg(OPT_massembler_no_warn);

  Opts.RelocationModel =

      std::string(Args.getLastArgValue(OPT_mrelocation_model, "pic"));

  Opts.TargetABI = std::string(Args.getLastArgValue(OPT_target_abi));

  Opts.IncrementalLinkerCompatible =

      Args.hasArg(OPT_mincremental_linker_compatible);

  Opts.SymbolDefs = Args.getAllArgValues(OPT_defsym);

  // EmbedBitcode Option. If -fembed-bitcode is enabled, set the flag.

  // EmbedBitcode behaves the same for all embed options for assembly files.

  if (auto *A = Args.getLastArg(OPT_fembed_bitcode_EQ)) {

    Opts.EmbedBitcode = llvm::StringSwitch<unsigned>(A->getValue())

                            .Case("all", 1)

                            .Case("bitcode", 1)

                            .Case("marker", 1)

                            .Default(0);

  }

  if (auto *A = Args.getLastArg(OPT_femit_dwarf_unwind_EQ)) {

    Opts.EmitDwarfUnwind =

        llvm::StringSwitch<EmitDwarfUnwindType>(A->getValue())

            .Case("always", EmitDwarfUnwindType::Always)

            .Case("no-compact-unwind", EmitDwarfUnwindType::NoCompactUnwind)

            .Case("default", EmitDwarfUnwindType::Default);

  }

  return Success;

}

static std::unique_ptr<raw_fd_ostream>

getOutputStream(StringRef Path, DiagnosticsEngine &Diags, bool Binary) {

  // Make sure that the Out file gets unlinked from the disk if we get a

  // SIGINT.

  if (Path != "-")

    sys::RemoveFileOnSignal(Path);

  std::error_code EC;

  auto Out = std::make_unique<raw_fd_ostream>(

      Path, EC, (Binary ? 
sys::fs::OF_None50
 : 
sys::fs::OF_TextWithCRLF5
));

  if (EC) {

    Diags.Report(diag::err_fe_unable_to_open_output) << Path << EC.message();

    return nullptr;

  }

  return Out;

}

static bool ExecuteAssemblerImpl(AssemblerInvocation &Opts,

                                 DiagnosticsEngine &Diags) {

  // Get the target specific parser.

  std::string Error;

  const Target *TheTarget = TargetRegistry::lookupTarget(Opts.Triple, Error);

  if (!TheTarget)

    return Diags.Report(diag::err_target_unknown_triple) << Opts.Triple;

  ErrorOr<std::unique_ptr<MemoryBuffer>> Buffer =

      MemoryBuffer::getFileOrSTDIN(Opts.InputFile, /*IsText=*/true);

  if (std::error_code EC = Buffer.getError()) {

    Error = EC.message();

    return Diags.Report(diag::err_fe_error_reading) << Opts.InputFile;

  }

  SourceMgr SrcMgr;

  // Tell SrcMgr about this buffer, which is what the parser will pick up.

  unsigned BufferIndex = SrcMgr.AddNewSourceBuffer(std::move(*Buffer), SMLoc());

  // Record the location of the include directories so that the lexer can find

  // it later.

  SrcMgr.setIncludeDirs(Opts.IncludePaths);

  std::unique_ptr<MCRegisterInfo> MRI(TheTarget->createMCRegInfo(Opts.Triple));

  assert(MRI && "Unable to create target register info!");

  MCTargetOptions MCOptions;

  MCOptions.EmitDwarfUnwind = Opts.EmitDwarfUnwind;

  std::unique_ptr<MCAsmInfo> MAI(

      TheTarget->createMCAsmInfo(*MRI, Opts.Triple, MCOptions));

  assert(MAI && "Unable to create target asm info!");

  // Ensure MCAsmInfo initialization occurs before any use, otherwise sections

  // may be created with a combination of default and explicit settings.

  MAI->setCompressDebugSections(Opts.CompressDebugSections);

  MAI->setRelaxELFRelocations(Opts.RelaxELFRelocations);

  bool IsBinary = Opts.OutputType == AssemblerInvocation::FT_Obj;

  if (Opts.OutputPath.empty())

    Opts.OutputPath = "-";

  std::unique_ptr<raw_fd_ostream> FDOS =

      getOutputStream(Opts.OutputPath, Diags, IsBinary);

  if (!FDOS)

    return true;

  std::unique_ptr<raw_fd_ostream> DwoOS;

  if (!Opts.SplitDwarfOutput.empty())

    DwoOS = getOutputStream(Opts.SplitDwarfOutput, Diags, IsBinary);

  // Build up the feature string from the target feature list.

  std::string FS = llvm::join(Opts.Features, ",");

  std::unique_ptr<MCSubtargetInfo> STI(

      TheTarget->createMCSubtargetInfo(Opts.Triple, Opts.CPU, FS));

  assert(STI && "Unable to create subtarget info!");

  MCContext Ctx(Triple(Opts.Triple), MAI.get(), MRI.get(), STI.get(), &SrcMgr,

                &MCOptions);

  bool PIC = false;

  if (Opts.RelocationModel == "static") {

    PIC = false;

  } else if (Opts.RelocationModel == "pic") {

    PIC = true;

  } else {

    assert(Opts.RelocationModel == "dynamic-no-pic" &&

           "Invalid PIC model!");

    PIC = false;

  }

  // FIXME: This is not pretty. MCContext has a ptr to MCObjectFileInfo and

  // MCObjectFileInfo needs a MCContext reference in order to initialize itself.

  std::unique_ptr<MCObjectFileInfo> MOFI(

      TheTarget->createMCObjectFileInfo(Ctx, PIC));

  if (Opts.DarwinTargetVariantTriple)

    MOFI->setDarwinTargetVariantTriple(*Opts.DarwinTargetVariantTriple);

  Ctx.setObjectFileInfo(MOFI.get());

  if (Opts.SaveTemporaryLabels)

    Ctx.setAllowTemporaryLabels(false);

  if (Opts.GenDwarfForAssembly)

    Ctx.setGenDwarfForAssembly(true);

  if (!Opts.DwarfDebugFlags.empty())

    Ctx.setDwarfDebugFlags(StringRef(Opts.DwarfDebugFlags));

  if (!Opts.DwarfDebugProducer.empty())

    Ctx.setDwarfDebugProducer(StringRef(Opts.DwarfDebugProducer));

  if (!Opts.DebugCompilationDir.empty())

    Ctx.setCompilationDir(Opts.DebugCompilationDir);

  else {

    // If no compilation dir is set, try to use the current directory.

    SmallString<128> CWD;

    if (!sys::fs::current_path(CWD))

      Ctx.setCompilationDir(CWD);

  }

  if (!Opts.DebugPrefixMap.empty())

    for (const auto &KV : Opts.DebugPrefixMap)

      Ctx.addDebugPrefixMapEntry(KV.first, KV.second);

  if (!Opts.MainFileName.empty())

    Ctx.setMainFileName(StringRef(Opts.MainFileName));

  Ctx.setDwarfFormat(Opts.Dwarf64 ? 
dwarf::DWARF641
 : 
dwarf::DWARF3253
);

  Ctx.setDwarfVersion(Opts.DwarfVersion);

  if (Opts.GenDwarfForAssembly)

    Ctx.setGenDwarfRootFile(Opts.InputFile,

                            SrcMgr.getMemoryBuffer(BufferIndex)->getBuffer());

  std::unique_ptr<MCStreamer> Str;

  std::unique_ptr<MCInstrInfo> MCII(TheTarget->createMCInstrInfo());

  assert(MCII && "Unable to create instruction info!");

  raw_pwrite_stream *Out = FDOS.get();

  std::unique_ptr<buffer_ostream> BOS;

  MCOptions.MCNoWarn = Opts.NoWarn;

  MCOptions.MCFatalWarnings = Opts.FatalWarnings;

  MCOptions.ABIName = Opts.TargetABI;

  // FIXME: There is a bit of code duplication with addPassesToEmitFile.

  if (Opts.OutputType == AssemblerInvocation::FT_Asm) {

    MCInstPrinter *IP = TheTarget->createMCInstPrinter(

        llvm::Triple(Opts.Triple), Opts.OutputAsmVariant, *MAI, *MCII, *MRI);

    std::unique_ptr<MCCodeEmitter> CE;

    if (Opts.ShowEncoding)

      CE.reset(TheTarget->createMCCodeEmitter(*MCII, Ctx));

    std::unique_ptr<MCAsmBackend> MAB(

        TheTarget->createMCAsmBackend(*STI, *MRI, MCOptions));

    auto FOut = std::make_unique<formatted_raw_ostream>(*Out);

    Str.reset(TheTarget->createAsmStreamer(

        Ctx, std::move(FOut), /*asmverbose*/ true,

        /*useDwarfDirectory*/ true, IP, std::move(CE), std::move(MAB),

        Opts.ShowInst));

  } else if (Opts.OutputType == AssemblerInvocation::FT_Null) {

    Str.reset(createNullStreamer(Ctx));

  } else {

    assert(Opts.OutputType == AssemblerInvocation::FT_Obj &&

           "Invalid file type!");

    if (!FDOS->supportsSeeking()) {

      BOS = std::make_unique<buffer_ostream>(*FDOS);

      Out = BOS.get();

    }

    std::unique_ptr<MCCodeEmitter> CE(

        TheTarget->createMCCodeEmitter(*MCII, Ctx));

    std::unique_ptr<MCAsmBackend> MAB(

        TheTarget->createMCAsmBackend(*STI, *MRI, MCOptions));

    assert(MAB && "Unable to create asm backend!");

    std::unique_ptr<MCObjectWriter> OW =

        DwoOS ? 
MAB->createDwoObjectWriter(*Out, *DwoOS)1

              : 
MAB->createObjectWriter(*Out)48
;

    Triple T(Opts.Triple);

    Str.reset(TheTarget->createMCObjectStreamer(

        T, Ctx, std::move(MAB), std::move(OW), std::move(CE), *STI,

        Opts.RelaxAll, Opts.IncrementalLinkerCompatible,

        /*DWARFMustBeAtTheEnd*/ true));

    Str.get()->initSections(Opts.NoExecStack, *STI);

  }

  // When -fembed-bitcode is passed to clang_as, a 1-byte marker

  // is emitted in __LLVM,__asm section if the object file is MachO format.

  if (Opts.EmbedBitcode && 
Ctx.getObjectFileType() == MCContext::IsMachO1
) {

    MCSection *AsmLabel = Ctx.getMachOSection(

        "__LLVM", "__asm", MachO::S_REGULAR, 4, SectionKind::getReadOnly());

    Str.get()->switchSection(AsmLabel);

    Str.get()->emitZeros(1);

  }

  // Assembly to object compilation should leverage assembly info.

  Str->setUseAssemblerInfoForParsing(true);

  bool Failed = false;

  std::unique_ptr<MCAsmParser> Parser(

      createMCAsmParser(SrcMgr, Ctx, *Str.get(), *MAI));

  // FIXME: init MCTargetOptions from sanitizer flags here.

  std::unique_ptr<MCTargetAsmParser> TAP(

      TheTarget->createMCAsmParser(*STI, *Parser, *MCII, MCOptions));

  if (!TAP)

    Failed = Diags.Report(diag::err_target_unknown_triple) << Opts.Triple;

  // Set values for symbols, if any.

  for (auto &S : Opts.SymbolDefs) {

    auto Pair = StringRef(S).split('=');

    auto Sym = Pair.first;

    auto Val = Pair.second;

    int64_t Value;

    // We have already error checked this in the driver.

    Val.getAsInteger(0, Value);

    Ctx.setSymbolValue(Parser->getStreamer(), Sym, Value);

  }

  if (!Failed) {

    Parser->setTargetParser(*TAP.get());

    Failed = Parser->Run(Opts.NoInitialTextSection);

  }

  return Failed;

}

static bool ExecuteAssembler(AssemblerInvocation &Opts,

                             DiagnosticsEngine &Diags) {

  bool Failed = ExecuteAssemblerImpl(Opts, Diags);

  // Delete output file if there were errors.

  if (Failed) {

    if (Opts.OutputPath != "-")

      sys::fs::remove(Opts.OutputPath);

    if (!Opts.SplitDwarfOutput.empty() && 
Opts.SplitDwarfOutput != "-"0
)

      sys::fs::remove(Opts.SplitDwarfOutput);

  }

  return Failed;

}

static void LLVMErrorHandler(void *UserData, const char *Message,

                             bool GenCrashDiag) {

  DiagnosticsEngine &Diags = *static_cast<DiagnosticsEngine*>(UserData);

  Diags.Report(diag::err_fe_error_backend) << Message;

  // We cannot recover from llvm errors.

  sys::Process::Exit(1);

}

int cc1as_main(ArrayRef<const char *> Argv, const char *Argv0, void *MainAddr) {

  // Initialize targets and assembly printers/parsers.

  InitializeAllTargetInfos();

  InitializeAllTargetMCs();

  InitializeAllAsmParsers();

  // Construct our diagnostic client.

  IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts = new DiagnosticOptions();

  TextDiagnosticPrinter *DiagClient

    = new TextDiagnosticPrinter(errs(), &*DiagOpts);

  DiagClient->setPrefix("clang -cc1as");

  IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs());

  DiagnosticsEngine Diags(DiagID, &*DiagOpts, DiagClient);

  // Set an error handler, so that any LLVM backend diagnostics go through our

  // error handler.

  ScopedFatalErrorHandler FatalErrorHandler

    (LLVMErrorHandler, static_cast<void*>(&Diags));

  // Parse the arguments.

  AssemblerInvocation Asm;

  if (!AssemblerInvocation::CreateFromArgs(Asm, Argv, Diags))

    return 1;

  if (Asm.ShowHelp) {

    getDriverOptTable().printHelp(

        llvm::outs(), "clang -cc1as [options] file...",

        "Clang Integrated Assembler",

        /*Include=*/driver::options::CC1AsOption, /*Exclude=*/0,

        /*ShowAllAliases=*/false);

    return 0;

  }

  // Honor -version.

  //

  // FIXME: Use a better -version message?

  if (Asm.ShowVersion) {

    llvm::cl::PrintVersionMessage();

    return 0;

  }

  // Honor -mllvm.

  //

  // FIXME: Remove this, one day.

  if (!Asm.LLVMArgs.empty()) {

    unsigned NumArgs = Asm.LLVMArgs.size();

    auto Args = std::make_unique<const char*[]>(NumArgs + 2);

    Args[0] = "clang (LLVM option parsing)";

    for (unsigned i = 0; i != NumArgs; 
++i17
)

      Args[i + 1] = Asm.LLVMArgs[i].c_str();

    Args[NumArgs + 1] = nullptr;

    llvm::cl::ParseCommandLineOptions(NumArgs + 1, Args.get());

  }

  // Execute the invocation, unless there were parsing errors.

  bool Failed = Diags.hasErrorOccurred() || ExecuteAssembler(Asm, Diags);

  // If any timers were active but haven't been destroyed yet, print their

  // results now.

  TimerGroup::printAll(errs());

  TimerGroup::clearAll();

  return !!Failed;

}