llvm/tools/llvm-mc/llvm-mc.cpp

   1 //===-- llvm-mc.cpp - Machine Code Hacking Driver ---------------*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This utility is a simple driver that allows command line hacking on machine
  10 // code.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "Disassembler.h"
  15 #include "llvm/MC/MCAsmBackend.h"
  16 #include "llvm/MC/MCAsmInfo.h"
  17 #include "llvm/MC/MCCodeEmitter.h"
  18 #include "llvm/MC/MCContext.h"
  19 #include "llvm/MC/MCInstPrinter.h"
  20 #include "llvm/MC/MCInstrInfo.h"
  21 #include "llvm/MC/MCObjectFileInfo.h"
  22 #include "llvm/MC/MCObjectWriter.h"
  23 #include "llvm/MC/MCParser/AsmLexer.h"
  24 #include "llvm/MC/MCParser/MCTargetAsmParser.h"
  25 #include "llvm/MC/MCRegisterInfo.h"
  26 #include "llvm/MC/MCStreamer.h"
  27 #include "llvm/MC/MCSubtargetInfo.h"
  28 #include "llvm/MC/MCTargetOptionsCommandFlags.h"
  29 #include "llvm/MC/TargetRegistry.h"
  30 #include "llvm/Support/CommandLine.h"
  31 #include "llvm/Support/Compression.h"
  32 #include "llvm/Support/FileUtilities.h"
  33 #include "llvm/Support/FormattedStream.h"
  34 #include "llvm/Support/InitLLVM.h"
  35 #include "llvm/Support/MemoryBuffer.h"
  36 #include "llvm/Support/SourceMgr.h"
  37 #include "llvm/Support/TargetSelect.h"
  38 #include "llvm/Support/ToolOutputFile.h"
  39 #include "llvm/Support/WithColor.h"
  40 #include "llvm/TargetParser/Host.h"
  41
  42 using namespace llvm;
  43
  44 static mc::RegisterMCTargetOptionsFlags MOF;
  45
  46 static cl::OptionCategory MCCategory("MC Options");
  47
  48 static cl::opt<std::string> InputFilename(cl::Positional,
  49                                           cl::desc("<input file>"),
  50                                           cl::init("-"), cl::cat(MCCategory));
  51
  52 static cl::list<std::string>
  53     DisassemblerOptions("M", cl::desc("Disassembler options"),
  54                         cl::cat(MCCategory));
  55
  56 static cl::opt<std::string> OutputFilename("o", cl::desc("Output filename"),
  57                                            cl::value_desc("filename"),
  58                                            cl::init("-"), cl::cat(MCCategory));
  59
  60 static cl::opt<std::string> SplitDwarfFile("split-dwarf-file",
  61                                            cl::desc("DWO output filename"),
  62                                            cl::value_desc("filename"),
  63                                            cl::cat(MCCategory));
  64
  65 static cl::opt<bool> ShowEncoding("show-encoding",
  66                                   cl::desc("Show instruction encodings"),
  67                                   cl::cat(MCCategory));
  68
  69 static cl::opt<bool> RelaxELFRel(
  70     "relax-relocations", cl::init(true),
  71     cl::desc("Emit R_X86_64_GOTPCRELX instead of R_X86_64_GOTPCREL"),
  72     cl::cat(MCCategory));
  73
  74 static cl::opt<DebugCompressionType> CompressDebugSections(
  75     "compress-debug-sections", cl::ValueOptional,
  76     cl::init(DebugCompressionType::None),
  77     cl::desc("Choose DWARF debug sections compression:"),
  78     cl::values(clEnumValN(DebugCompressionType::None, "none", "No compression"),
  79                clEnumValN(DebugCompressionType::Zlib, "zlib", "Use zlib"),
  80                clEnumValN(DebugCompressionType::Zstd, "zstd", "Use zstd")),
  81     cl::cat(MCCategory));
  82
  83 static cl::opt<bool>
  84     ShowInst("show-inst", cl::desc("Show internal instruction representation"),
  85              cl::cat(MCCategory));
  86
  87 static cl::opt<bool>
  88     ShowInstOperands("show-inst-operands",
  89                      cl::desc("Show instructions operands as parsed"),
  90                      cl::cat(MCCategory));
  91
  92 static cl::opt<unsigned>
  93     OutputAsmVariant("output-asm-variant",
  94                      cl::desc("Syntax variant to use for output printing"),
  95                      cl::cat(MCCategory));
  96
  97 static cl::opt<bool>
  98     PrintImmHex("print-imm-hex", cl::init(false),
  99                 cl::desc("Prefer hex format for immediate values"),
 100                 cl::cat(MCCategory));
 101
 102 static cl::list<std::string>
 103     DefineSymbol("defsym",
 104                  cl::desc("Defines a symbol to be an integer constant"),
 105                  cl::cat(MCCategory));
 106
 107 static cl::opt<bool>
 108     PreserveComments("preserve-comments",
 109                      cl::desc("Preserve Comments in outputted assembly"),
 110                      cl::cat(MCCategory));
 111
 112 enum OutputFileType {
 113   OFT_Null,
 114   OFT_AssemblyFile,
 115   OFT_ObjectFile
 116 };
 117 static cl::opt<OutputFileType>
 118     FileType("filetype", cl::init(OFT_AssemblyFile),
 119              cl::desc("Choose an output file type:"),
 120              cl::values(clEnumValN(OFT_AssemblyFile, "asm",
 121                                    "Emit an assembly ('.s') file"),
 122                         clEnumValN(OFT_Null, "null",
 123                                    "Don't emit anything (for timing purposes)"),
 124                         clEnumValN(OFT_ObjectFile, "obj",
 125                                    "Emit a native object ('.o') file")),
 126              cl::cat(MCCategory));
 127
 128 static cl::list<std::string> IncludeDirs("I",
 129                                          cl::desc("Directory of include files"),
 130                                          cl::value_desc("directory"),
 131                                          cl::Prefix, cl::cat(MCCategory));
 132
 133 static cl::opt<std::string>
 134     ArchName("arch",
 135              cl::desc("Target arch to assemble for, "
 136                       "see -version for available targets"),
 137              cl::cat(MCCategory));
 138
 139 static cl::opt<std::string>
 140     TripleName("triple",
 141                cl::desc("Target triple to assemble for, "
 142                         "see -version for available targets"),
 143                cl::cat(MCCategory));
 144
 145 static cl::opt<std::string>
 146     MCPU("mcpu",
 147          cl::desc("Target a specific cpu type (-mcpu=help for details)"),
 148          cl::value_desc("cpu-name"), cl::init(""), cl::cat(MCCategory));
 149
 150 static cl::list<std::string>
 151     MAttrs("mattr", cl::CommaSeparated,
 152            cl::desc("Target specific attributes (-mattr=help for details)"),
 153            cl::value_desc("a1,+a2,-a3,..."), cl::cat(MCCategory));
 154
 155 static cl::opt<bool> PIC("position-independent",
 156                          cl::desc("Position independent"), cl::init(false),
 157                          cl::cat(MCCategory));
 158
 159 static cl::opt<bool>
 160     LargeCodeModel("large-code-model",
 161                    cl::desc("Create cfi directives that assume the code might "
 162                             "be more than 2gb away"),
 163                    cl::cat(MCCategory));
 164
 165 static cl::opt<bool>
 166     NoInitialTextSection("n",
 167                          cl::desc("Don't assume assembly file starts "
 168                                   "in the text section"),
 169                          cl::cat(MCCategory));
 170
 171 static cl::opt<bool>
 172     GenDwarfForAssembly("g",
 173                         cl::desc("Generate dwarf debugging info for assembly "
 174                                  "source files"),
 175                         cl::cat(MCCategory));
 176
 177 static cl::opt<std::string>
 178     DebugCompilationDir("fdebug-compilation-dir",
 179                         cl::desc("Specifies the debug info's compilation dir"),
 180                         cl::cat(MCCategory));
 181
 182 static cl::list<std::string> DebugPrefixMap(
 183     "fdebug-prefix-map", cl::desc("Map file source paths in debug info"),
 184     cl::value_desc("= separated key-value pairs"), cl::cat(MCCategory));
 185
 186 static cl::opt<std::string> MainFileName(
 187     "main-file-name",
 188     cl::desc("Specifies the name we should consider the input file"),
 189     cl::cat(MCCategory));
 190
 191 static cl::opt<bool> SaveTempLabels("save-temp-labels",
 192                                     cl::desc("Don't discard temporary labels"),
 193                                     cl::cat(MCCategory));
 194
 195 static cl::opt<bool> LexMasmIntegers(
 196     "masm-integers",
 197     cl::desc("Enable binary and hex masm integers (0b110 and 0ABCh)"),
 198     cl::cat(MCCategory));
 199
 200 static cl::opt<bool> LexMasmHexFloats(
 201     "masm-hexfloats",
 202     cl::desc("Enable MASM-style hex float initializers (3F800000r)"),
 203     cl::cat(MCCategory));
 204
 205 static cl::opt<bool> LexMotorolaIntegers(
 206     "motorola-integers",
 207     cl::desc("Enable binary and hex Motorola integers (%110 and $ABC)"),
 208     cl::cat(MCCategory));
 209
 210 static cl::opt<bool> NoExecStack("no-exec-stack",
 211                                  cl::desc("File doesn't need an exec stack"),
 212                                  cl::cat(MCCategory));
 213
 214 enum ActionType {
 215   AC_AsLex,
 216   AC_Assemble,
 217   AC_Disassemble,
 218   AC_MDisassemble,
 219   AC_CDisassemble,
 220 };
 221
 222 static cl::opt<ActionType> Action(
 223     cl::desc("Action to perform:"), cl::init(AC_Assemble),
 224     cl::values(clEnumValN(AC_AsLex, "as-lex", "Lex tokens from a .s file"),
 225                clEnumValN(AC_Assemble, "assemble",
 226                           "Assemble a .s file (default)"),
 227                clEnumValN(AC_Disassemble, "disassemble",
 228                           "Disassemble strings of hex bytes"),
 229                clEnumValN(AC_MDisassemble, "mdis",
 230                           "Marked up disassembly of strings of hex bytes"),
 231                clEnumValN(AC_CDisassemble, "cdis",
 232                           "Colored disassembly of strings of hex bytes")),
 233     cl::cat(MCCategory));
 234
 235 static const Target *GetTarget(const char *ProgName) {
 236   // Figure out the target triple.
 237   if (TripleName.empty())
 238     TripleName = sys::getDefaultTargetTriple();
 239   Triple TheTriple(Triple::normalize(TripleName));
 240
 241   // Get the target specific parser.
 242   std::string Error;
 243   const Target *TheTarget = TargetRegistry::lookupTarget(ArchName, TheTriple,
 244                                                          Error);
 245   if (!TheTarget) {
 246     WithColor::error(errs(), ProgName) << Error;
 247     return nullptr;
 248   }
 249
 250   // Update the triple name and return the found target.
 251   TripleName = TheTriple.getTriple();
 252   return TheTarget;
 253 }
 254
 255 static std::unique_ptr<ToolOutputFile> GetOutputStream(StringRef Path,
 256     sys::fs::OpenFlags Flags) {
 257   std::error_code EC;
 258   auto Out = std::make_unique<ToolOutputFile>(Path, EC, Flags);
 259   if (EC) {
 260     WithColor::error() << EC.message() << '\n';
 261     return nullptr;
 262   }
 263
 264   return Out;
 265 }
 266
 267 static std::string DwarfDebugFlags;
 268 static void setDwarfDebugFlags(int argc, char **argv) {
 269   if (!getenv("RC_DEBUG_OPTIONS"))
 270     return;
 271   for (int i = 0; i < argc; i++) {
 272     DwarfDebugFlags += argv[i];
 273     if (i + 1 < argc)
 274       DwarfDebugFlags += " ";
 275   }
 276 }
 277
 278 static std::string DwarfDebugProducer;
 279 static void setDwarfDebugProducer() {
 280   if(!getenv("DEBUG_PRODUCER"))
 281     return;
 282   DwarfDebugProducer += getenv("DEBUG_PRODUCER");
 283 }
 284
 285 static int AsLexInput(SourceMgr &SrcMgr, MCAsmInfo &MAI,
 286                       raw_ostream &OS) {
 287
 288   AsmLexer Lexer(MAI);
 289   Lexer.setBuffer(SrcMgr.getMemoryBuffer(SrcMgr.getMainFileID())->getBuffer());
 290
 291   bool Error = false;
 292   while (Lexer.Lex().isNot(AsmToken::Eof)) {
 293     Lexer.getTok().dump(OS);
 294     OS << "\n";
 295     if (Lexer.getTok().getKind() == AsmToken::Error)
 296       Error = true;
 297   }
 298
 299   return Error;
 300 }
 301
 302 static int fillCommandLineSymbols(MCAsmParser &Parser) {
 303   for (auto &I: DefineSymbol) {
 304     auto Pair = StringRef(I).split('=');
 305     auto Sym = Pair.first;
 306     auto Val = Pair.second;
 307
 308     if (Sym.empty() || Val.empty()) {
 309       WithColor::error() << "defsym must be of the form: sym=value: " << I
 310                          << "\n";
 311       return 1;
 312     }
 313     int64_t Value;
 314     if (Val.getAsInteger(0, Value)) {
 315       WithColor::error() << "value is not an integer: " << Val << "\n";
 316       return 1;
 317     }
 318     Parser.getContext().setSymbolValue(Parser.getStreamer(), Sym, Value);
 319   }
 320   return 0;
 321 }
 322
 323 static int AssembleInput(const char *ProgName, const Target *TheTarget,
 324                          SourceMgr &SrcMgr, MCContext &Ctx, MCStreamer &Str,
 325                          MCAsmInfo &MAI, MCSubtargetInfo &STI,
 326                          MCInstrInfo &MCII, MCTargetOptions const &MCOptions) {
 327   std::unique_ptr<MCAsmParser> Parser(
 328       createMCAsmParser(SrcMgr, Ctx, Str, MAI));
 329   std::unique_ptr<MCTargetAsmParser> TAP(
 330       TheTarget->createMCAsmParser(STI, *Parser, MCII, MCOptions));
 331
 332   if (!TAP) {
 333     WithColor::error(errs(), ProgName)
 334         << "this target does not support assembly parsing.\n";
 335     return 1;
 336   }
 337
 338   int SymbolResult = fillCommandLineSymbols(*Parser);
 339   if(SymbolResult)
 340     return SymbolResult;
 341   Parser->setShowParsedOperands(ShowInstOperands);
 342   Parser->setTargetParser(*TAP);
 343   Parser->getLexer().setLexMasmIntegers(LexMasmIntegers);
 344   Parser->getLexer().setLexMasmHexFloats(LexMasmHexFloats);
 345   Parser->getLexer().setLexMotorolaIntegers(LexMotorolaIntegers);
 346
 347   int Res = Parser->Run(NoInitialTextSection);
 348
 349   return Res;
 350 }
 351
 352 int main(int argc, char **argv) {
 353   InitLLVM X(argc, argv);
 354
 355   // Initialize targets and assembly printers/parsers.
 356   llvm::InitializeAllTargetInfos();
 357   llvm::InitializeAllTargetMCs();
 358   llvm::InitializeAllAsmParsers();
 359   llvm::InitializeAllDisassemblers();
 360
 361   // Register the target printer for --version.
 362   cl::AddExtraVersionPrinter(TargetRegistry::printRegisteredTargetsForVersion);
 363
 364   cl::HideUnrelatedOptions({&MCCategory, &getColorCategory()});
 365   cl::ParseCommandLineOptions(argc, argv, "llvm machine code playground\n");
 366   const MCTargetOptions MCOptions = mc::InitMCTargetOptionsFromFlags();
 367   setDwarfDebugFlags(argc, argv);
 368
 369   setDwarfDebugProducer();
 370
 371   const char *ProgName = argv[0];
 372   const Target *TheTarget = GetTarget(ProgName);
 373   if (!TheTarget)
 374     return 1;
 375   // Now that GetTarget() has (potentially) replaced TripleName, it's safe to
 376   // construct the Triple object.
 377   Triple TheTriple(TripleName);
 378
 379   ErrorOr<std::unique_ptr<MemoryBuffer>> BufferPtr =
 380       MemoryBuffer::getFileOrSTDIN(InputFilename, /*IsText=*/true);
 381   if (std::error_code EC = BufferPtr.getError()) {
 382     WithColor::error(errs(), ProgName)
 383         << InputFilename << ": " << EC.message() << '\n';
 384     return 1;
 385   }
 386   MemoryBuffer *Buffer = BufferPtr->get();
 387
 388   SourceMgr SrcMgr;
 389
 390   // Tell SrcMgr about this buffer, which is what the parser will pick up.
 391   SrcMgr.AddNewSourceBuffer(std::move(*BufferPtr), SMLoc());
 392
 393   // Record the location of the include directories so that the lexer can find
 394   // it later.
 395   SrcMgr.setIncludeDirs(IncludeDirs);
 396
 397   std::unique_ptr<MCRegisterInfo> MRI(TheTarget->createMCRegInfo(TripleName));
 398   assert(MRI && "Unable to create target register info!");
 399
 400   std::unique_ptr<MCAsmInfo> MAI(
 401       TheTarget->createMCAsmInfo(*MRI, TripleName, MCOptions));
 402   assert(MAI && "Unable to create target asm info!");
 403
 404   MAI->setRelaxELFRelocations(RelaxELFRel);
 405   if (CompressDebugSections != DebugCompressionType::None) {
 406     if (const char *Reason = compression::getReasonIfUnsupported(
 407             compression::formatFor(CompressDebugSections))) {
 408       WithColor::error(errs(), ProgName)
 409           << "--compress-debug-sections: " << Reason;
 410       return 1;
 411     }
 412   }
 413   MAI->setCompressDebugSections(CompressDebugSections);
 414   MAI->setPreserveAsmComments(PreserveComments);
 415
 416   // Package up features to be passed to target/subtarget
 417   std::string FeaturesStr;
 418   if (MAttrs.size()) {
 419     SubtargetFeatures Features;
 420     for (unsigned i = 0; i != MAttrs.size(); ++i)
 421       Features.AddFeature(MAttrs[i]);
 422     FeaturesStr = Features.getString();
 423   }
 424
 425   std::unique_ptr<MCSubtargetInfo> STI(
 426       TheTarget->createMCSubtargetInfo(TripleName, MCPU, FeaturesStr));
 427   assert(STI && "Unable to create subtarget info!");
 428
 429   // FIXME: This is not pretty. MCContext has a ptr to MCObjectFileInfo and
 430   // MCObjectFileInfo needs a MCContext reference in order to initialize itself.
 431   MCContext Ctx(TheTriple, MAI.get(), MRI.get(), STI.get(), &SrcMgr,
 432                 &MCOptions);
 433   std::unique_ptr<MCObjectFileInfo> MOFI(
 434       TheTarget->createMCObjectFileInfo(Ctx, PIC, LargeCodeModel));
 435   Ctx.setObjectFileInfo(MOFI.get());
 436
 437   if (SaveTempLabels)
 438     Ctx.setAllowTemporaryLabels(false);
 439
 440   Ctx.setGenDwarfForAssembly(GenDwarfForAssembly);
 441   // Default to 4 for dwarf version.
 442   unsigned DwarfVersion = MCOptions.DwarfVersion ? MCOptions.DwarfVersion : 4;
 443   if (DwarfVersion < 2 || DwarfVersion > 5) {
 444     errs() << ProgName << ": Dwarf version " << DwarfVersion
 445            << " is not supported." << '\n';
 446     return 1;
 447   }
 448   Ctx.setDwarfVersion(DwarfVersion);
 449   if (MCOptions.Dwarf64) {
 450     // The 64-bit DWARF format was introduced in DWARFv3.
 451     if (DwarfVersion < 3) {
 452       errs() << ProgName
 453              << ": the 64-bit DWARF format is not supported for DWARF versions "
 454                 "prior to 3\n";
 455       return 1;
 456     }
 457     // 32-bit targets don't support DWARF64, which requires 64-bit relocations.
 458     if (MAI->getCodePointerSize() < 8) {
 459       errs() << ProgName
 460              << ": the 64-bit DWARF format is only supported for 64-bit "
 461                 "targets\n";
 462       return 1;
 463     }
 464     // If needsDwarfSectionOffsetDirective is true, we would eventually call
 465     // MCStreamer::emitSymbolValue() with IsSectionRelative = true, but that
 466     // is supported only for 4-byte long references.
 467     if (MAI->needsDwarfSectionOffsetDirective()) {
 468       errs() << ProgName << ": the 64-bit DWARF format is not supported for "
 469              << TheTriple.normalize() << "\n";
 470       return 1;
 471     }
 472     Ctx.setDwarfFormat(dwarf::DWARF64);
 473   }
 474   if (!DwarfDebugFlags.empty())
 475     Ctx.setDwarfDebugFlags(StringRef(DwarfDebugFlags));
 476   if (!DwarfDebugProducer.empty())
 477     Ctx.setDwarfDebugProducer(StringRef(DwarfDebugProducer));
 478   if (!DebugCompilationDir.empty())
 479     Ctx.setCompilationDir(DebugCompilationDir);
 480   else {
 481     // If no compilation dir is set, try to use the current directory.
 482     SmallString<128> CWD;
 483     if (!sys::fs::current_path(CWD))
 484       Ctx.setCompilationDir(CWD);
 485   }
 486   for (const auto &Arg : DebugPrefixMap) {
 487     const auto &KV = StringRef(Arg).split('=');
 488     Ctx.addDebugPrefixMapEntry(std::string(KV.first), std::string(KV.second));
 489   }
 490   if (!MainFileName.empty())
 491     Ctx.setMainFileName(MainFileName);
 492   if (GenDwarfForAssembly)
 493     Ctx.setGenDwarfRootFile(InputFilename, Buffer->getBuffer());
 494
 495   sys::fs::OpenFlags Flags = (FileType == OFT_AssemblyFile)
 496                                  ? sys::fs::OF_TextWithCRLF
 497                                  : sys::fs::OF_None;
 498   std::unique_ptr<ToolOutputFile> Out = GetOutputStream(OutputFilename, Flags);
 499   if (!Out)
 500     return 1;
 501
 502   std::unique_ptr<ToolOutputFile> DwoOut;
 503   if (!SplitDwarfFile.empty()) {
 504     if (FileType != OFT_ObjectFile) {
 505       WithColor::error() << "dwo output only supported with object files\n";
 506       return 1;
 507     }
 508     DwoOut = GetOutputStream(SplitDwarfFile, sys::fs::OF_None);
 509     if (!DwoOut)
 510       return 1;
 511   }
 512
 513   std::unique_ptr<buffer_ostream> BOS;
 514   raw_pwrite_stream *OS = &Out->os();
 515   std::unique_ptr<MCStreamer> Str;
 516
 517   std::unique_ptr<MCInstrInfo> MCII(TheTarget->createMCInstrInfo());
 518   assert(MCII && "Unable to create instruction info!");
 519
 520   MCInstPrinter *IP = nullptr;
 521   if (FileType == OFT_AssemblyFile) {
 522     IP = TheTarget->createMCInstPrinter(Triple(TripleName), OutputAsmVariant,
 523                                         *MAI, *MCII, *MRI);
 524
 525     if (!IP) {
 526       WithColor::error()
 527           << "unable to create instruction printer for target triple '"
 528           << TheTriple.normalize() << "' with assembly variant "
 529           << OutputAsmVariant << ".\n";
 530       return 1;
 531     }
 532
 533     for (StringRef Opt : DisassemblerOptions)
 534       if (!IP->applyTargetSpecificCLOption(Opt)) {
 535         WithColor::error() << "invalid disassembler option '" << Opt << "'\n";
 536         return 1;
 537       }
 538
 539     // Set the display preference for hex vs. decimal immediates.
 540     IP->setPrintImmHex(PrintImmHex);
 541
 542     // Set up the AsmStreamer.
 543     std::unique_ptr<MCCodeEmitter> CE;
 544     if (ShowEncoding)
 545       CE.reset(TheTarget->createMCCodeEmitter(*MCII, Ctx));
 546
 547     std::unique_ptr<MCAsmBackend> MAB(
 548         TheTarget->createMCAsmBackend(*STI, *MRI, MCOptions));
 549     auto FOut = std::make_unique<formatted_raw_ostream>(*OS);
 550     // FIXME: Workaround for bug in formatted_raw_ostream. Color escape codes
 551     // are (incorrectly) written directly to the unbuffered raw_ostream wrapped
 552     // by the formatted_raw_ostream.
 553     if (Action == AC_CDisassemble)
 554       FOut->SetUnbuffered();
 555     Str.reset(
 556         TheTarget->createAsmStreamer(Ctx, std::move(FOut), /*asmverbose*/ true,
 557                                      /*useDwarfDirectory*/ true, IP,
 558                                      std::move(CE), std::move(MAB), ShowInst));
 559
 560   } else if (FileType == OFT_Null) {
 561     Str.reset(TheTarget->createNullStreamer(Ctx));
 562   } else {
 563     assert(FileType == OFT_ObjectFile && "Invalid file type!");
 564
 565     if (!Out->os().supportsSeeking()) {
 566       BOS = std::make_unique<buffer_ostream>(Out->os());
 567       OS = BOS.get();
 568     }
 569
 570     MCCodeEmitter *CE = TheTarget->createMCCodeEmitter(*MCII, Ctx);
 571     MCAsmBackend *MAB = TheTarget->createMCAsmBackend(*STI, *MRI, MCOptions);
 572     Str.reset(TheTarget->createMCObjectStreamer(
 573         TheTriple, Ctx, std::unique_ptr<MCAsmBackend>(MAB),
 574         DwoOut ? MAB->createDwoObjectWriter(*OS, DwoOut->os())
 575                : MAB->createObjectWriter(*OS),
 576         std::unique_ptr<MCCodeEmitter>(CE), *STI, MCOptions.MCRelaxAll,
 577         MCOptions.MCIncrementalLinkerCompatible,
 578         /*DWARFMustBeAtTheEnd*/ false));
 579     if (NoExecStack)
 580       Str->initSections(true, *STI);
 581   }
 582
 583   // Use Assembler information for parsing.
 584   Str->setUseAssemblerInfoForParsing(true);
 585
 586   int Res = 1;
 587   bool disassemble = false;
 588   switch (Action) {
 589   case AC_AsLex:
 590     Res = AsLexInput(SrcMgr, *MAI, Out->os());
 591     break;
 592   case AC_Assemble:
 593     Res = AssembleInput(ProgName, TheTarget, SrcMgr, Ctx, *Str, *MAI, *STI,
 594                         *MCII, MCOptions);
 595     break;
 596   case AC_MDisassemble:
 597     IP->setUseMarkup(true);
 598     disassemble = true;
 599     break;
 600   case AC_CDisassemble:
 601     IP->setUseColor(true);
 602     disassemble = true;
 603     break;
 604   case AC_Disassemble:
 605     disassemble = true;
 606     break;
 607   }
 608   if (disassemble)
 609     Res = Disassembler::disassemble(*TheTarget, TripleName, *STI, *Str, *Buffer,
 610                                     SrcMgr, Ctx, MCOptions);
 611
 612   // Keep output if no errors.
 613   if (Res == 0) {
 614     Out->keep();
 615     if (DwoOut)
 616       DwoOut->keep();
 617   }
 618   return Res;
 619 }