tools/llvm-mc/llvm-mc.cpp

   1 //===-- llvm-mc.cpp - Machine Code Hacking Driver ---------------*- C++ -*-===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // This utility is a simple driver that allows command line hacking on machine
  11 // code.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "Disassembler.h"
  16 #include "llvm/MC/MCAsmBackend.h"
  17 #include "llvm/MC/MCAsmInfo.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/MCParser/AsmLexer.h"
  23 #include "llvm/MC/MCParser/MCTargetAsmParser.h"
  24 #include "llvm/MC/MCRegisterInfo.h"
  25 #include "llvm/MC/MCSectionMachO.h"
  26 #include "llvm/MC/MCStreamer.h"
  27 #include "llvm/MC/MCSubtargetInfo.h"
  28 #include "llvm/MC/MCTargetOptionsCommandFlags.h"
  29 #include "llvm/Support/CommandLine.h"
  30 #include "llvm/Support/Compression.h"
  31 #include "llvm/Support/FileUtilities.h"
  32 #include "llvm/Support/FormattedStream.h"
  33 #include "llvm/Support/Host.h"
  34 #include "llvm/Support/ManagedStatic.h"
  35 #include "llvm/Support/MemoryBuffer.h"
  36 #include "llvm/Support/PrettyStackTrace.h"
  37 #include "llvm/Support/Signals.h"
  38 #include "llvm/Support/SourceMgr.h"
  39 #include "llvm/Support/TargetRegistry.h"
  40 #include "llvm/Support/TargetSelect.h"
  41 #include "llvm/Support/ToolOutputFile.h"
  42
  43 using namespace llvm;
  44
  45 static cl::opt<std::string>
  46 InputFilename(cl::Positional, cl::desc("<input file>"), cl::init("-"));
  47
  48 static cl::opt<std::string>
  49 OutputFilename("o", cl::desc("Output filename"),
  50                cl::value_desc("filename"));
  51
  52 static cl::opt<bool>
  53 ShowEncoding("show-encoding", cl::desc("Show instruction encodings"));
  54
  55 static cl::opt<bool> RelaxELFRel(
  56     "relax-relocations", cl::init(true),
  57     cl::desc("Emit R_X86_64_GOTPCRELX instead of R_X86_64_GOTPCREL"));
  58
  59 static cl::opt<DebugCompressionType> CompressDebugSections(
  60     "compress-debug-sections", cl::ValueOptional,
  61     cl::init(DebugCompressionType::None),
  62     cl::desc("Choose DWARF debug sections compression:"),
  63     cl::values(clEnumValN(DebugCompressionType::None, "none", "No compression"),
  64                clEnumValN(DebugCompressionType::Z, "zlib",
  65                           "Use zlib compression"),
  66                clEnumValN(DebugCompressionType::GNU, "zlib-gnu",
  67                           "Use zlib-gnu compression (deprecated)")));
  68
  69 static cl::opt<bool>
  70 ShowInst("show-inst", cl::desc("Show internal instruction representation"));
  71
  72 static cl::opt<bool>
  73 ShowInstOperands("show-inst-operands",
  74                  cl::desc("Show instructions operands as parsed"));
  75
  76 static cl::opt<unsigned>
  77 OutputAsmVariant("output-asm-variant",
  78                  cl::desc("Syntax variant to use for output printing"));
  79
  80 static cl::opt<bool>
  81 PrintImmHex("print-imm-hex", cl::init(false),
  82             cl::desc("Prefer hex format for immediate values"));
  83
  84 static cl::list<std::string>
  85 DefineSymbol("defsym", cl::desc("Defines a symbol to be an integer constant"));
  86
  87 static cl::opt<bool>
  88     PreserveComments("preserve-comments",
  89                      cl::desc("Preserve Comments in outputted assembly"));
  90
  91 enum OutputFileType {
  92   OFT_Null,
  93   OFT_AssemblyFile,
  94   OFT_ObjectFile
  95 };
  96 static cl::opt<OutputFileType>
  97 FileType("filetype", cl::init(OFT_AssemblyFile),
  98   cl::desc("Choose an output file type:"),
  99   cl::values(
 100        clEnumValN(OFT_AssemblyFile, "asm",
 101                   "Emit an assembly ('.s') file"),
 102        clEnumValN(OFT_Null, "null",
 103                   "Don't emit anything (for timing purposes)"),
 104        clEnumValN(OFT_ObjectFile, "obj",
 105                   "Emit a native object ('.o') file")));
 106
 107 static cl::list<std::string>
 108 IncludeDirs("I", cl::desc("Directory of include files"),
 109             cl::value_desc("directory"), cl::Prefix);
 110
 111 static cl::opt<std::string>
 112 ArchName("arch", cl::desc("Target arch to assemble for, "
 113                           "see -version for available targets"));
 114
 115 static cl::opt<std::string>
 116 TripleName("triple", cl::desc("Target triple to assemble for, "
 117                               "see -version for available targets"));
 118
 119 static cl::opt<std::string>
 120 MCPU("mcpu",
 121      cl::desc("Target a specific cpu type (-mcpu=help for details)"),
 122      cl::value_desc("cpu-name"),
 123      cl::init(""));
 124
 125 static cl::list<std::string>
 126 MAttrs("mattr",
 127   cl::CommaSeparated,
 128   cl::desc("Target specific attributes (-mattr=help for details)"),
 129   cl::value_desc("a1,+a2,-a3,..."));
 130
 131 static cl::opt<bool> PIC("position-independent",
 132                          cl::desc("Position independent"), cl::init(false));
 133
 134 static cl::opt<bool>
 135     LargeCodeModel("large-code-model",
 136                    cl::desc("Create cfi directives that assume the code might "
 137                             "be more than 2gb away"));
 138
 139 static cl::opt<bool>
 140 NoInitialTextSection("n", cl::desc("Don't assume assembly file starts "
 141                                    "in the text section"));
 142
 143 static cl::opt<bool>
 144 GenDwarfForAssembly("g", cl::desc("Generate dwarf debugging info for assembly "
 145                                   "source files"));
 146
 147 static cl::opt<std::string>
 148 DebugCompilationDir("fdebug-compilation-dir",
 149                     cl::desc("Specifies the debug info's compilation dir"));
 150
 151 static cl::opt<std::string>
 152 MainFileName("main-file-name",
 153              cl::desc("Specifies the name we should consider the input file"));
 154
 155 static cl::opt<bool> SaveTempLabels("save-temp-labels",
 156                                     cl::desc("Don't discard temporary labels"));
 157
 158 static cl::opt<bool> NoExecStack("no-exec-stack",
 159                                  cl::desc("File doesn't need an exec stack"));
 160
 161 enum ActionType {
 162   AC_AsLex,
 163   AC_Assemble,
 164   AC_Disassemble,
 165   AC_MDisassemble,
 166 };
 167
 168 static cl::opt<ActionType>
 169 Action(cl::desc("Action to perform:"),
 170        cl::init(AC_Assemble),
 171        cl::values(clEnumValN(AC_AsLex, "as-lex",
 172                              "Lex tokens from a .s file"),
 173                   clEnumValN(AC_Assemble, "assemble",
 174                              "Assemble a .s file (default)"),
 175                   clEnumValN(AC_Disassemble, "disassemble",
 176                              "Disassemble strings of hex bytes"),
 177                   clEnumValN(AC_MDisassemble, "mdis",
 178                              "Marked up disassembly of strings of hex bytes")));
 179
 180 static const Target *GetTarget(const char *ProgName) {
 181   // Figure out the target triple.
 182   if (TripleName.empty())
 183     TripleName = sys::getDefaultTargetTriple();
 184   Triple TheTriple(Triple::normalize(TripleName));
 185
 186   // Get the target specific parser.
 187   std::string Error;
 188   const Target *TheTarget = TargetRegistry::lookupTarget(ArchName, TheTriple,
 189                                                          Error);
 190   if (!TheTarget) {
 191     errs() << ProgName << ": " << Error;
 192     return nullptr;
 193   }
 194
 195   // Update the triple name and return the found target.
 196   TripleName = TheTriple.getTriple();
 197   return TheTarget;
 198 }
 199
 200 static std::unique_ptr<tool_output_file> GetOutputStream() {
 201   if (OutputFilename == "")
 202     OutputFilename = "-";
 203
 204   std::error_code EC;
 205   auto Out = llvm::make_unique<tool_output_file>(OutputFilename, EC,
 206                                                  sys::fs::F_None);
 207   if (EC) {
 208     errs() << EC.message() << '\n';
 209     return nullptr;
 210   }
 211
 212   return Out;
 213 }
 214
 215 static std::string DwarfDebugFlags;
 216 static void setDwarfDebugFlags(int argc, char **argv) {
 217   if (!getenv("RC_DEBUG_OPTIONS"))
 218     return;
 219   for (int i = 0; i < argc; i++) {
 220     DwarfDebugFlags += argv[i];
 221     if (i + 1 < argc)
 222       DwarfDebugFlags += " ";
 223   }
 224 }
 225
 226 static std::string DwarfDebugProducer;
 227 static void setDwarfDebugProducer() {
 228   if(!getenv("DEBUG_PRODUCER"))
 229     return;
 230   DwarfDebugProducer += getenv("DEBUG_PRODUCER");
 231 }
 232
 233 static int AsLexInput(SourceMgr &SrcMgr, MCAsmInfo &MAI,
 234                       raw_ostream &OS) {
 235
 236   AsmLexer Lexer(MAI);
 237   Lexer.setBuffer(SrcMgr.getMemoryBuffer(SrcMgr.getMainFileID())->getBuffer());
 238
 239   bool Error = false;
 240   while (Lexer.Lex().isNot(AsmToken::Eof)) {
 241     const AsmToken &Tok = Lexer.getTok();
 242
 243     switch (Tok.getKind()) {
 244     default:
 245       SrcMgr.PrintMessage(Lexer.getLoc(), SourceMgr::DK_Warning,
 246                           "unknown token");
 247       Error = true;
 248       break;
 249     case AsmToken::Error:
 250       Error = true; // error already printed.
 251       break;
 252     case AsmToken::Identifier:
 253       OS << "identifier: " << Lexer.getTok().getString();
 254       break;
 255     case AsmToken::Integer:
 256       OS << "int: " << Lexer.getTok().getString();
 257       break;
 258     case AsmToken::Real:
 259       OS << "real: " << Lexer.getTok().getString();
 260       break;
 261     case AsmToken::String:
 262       OS << "string: " << Lexer.getTok().getString();
 263       break;
 264
 265     case AsmToken::Amp:            OS << "Amp"; break;
 266     case AsmToken::AmpAmp:         OS << "AmpAmp"; break;
 267     case AsmToken::At:             OS << "At"; break;
 268     case AsmToken::Caret:          OS << "Caret"; break;
 269     case AsmToken::Colon:          OS << "Colon"; break;
 270     case AsmToken::Comma:          OS << "Comma"; break;
 271     case AsmToken::Dollar:         OS << "Dollar"; break;
 272     case AsmToken::Dot:            OS << "Dot"; break;
 273     case AsmToken::EndOfStatement: OS << "EndOfStatement"; break;
 274     case AsmToken::Eof:            OS << "Eof"; break;
 275     case AsmToken::Equal:          OS << "Equal"; break;
 276     case AsmToken::EqualEqual:     OS << "EqualEqual"; break;
 277     case AsmToken::Exclaim:        OS << "Exclaim"; break;
 278     case AsmToken::ExclaimEqual:   OS << "ExclaimEqual"; break;
 279     case AsmToken::Greater:        OS << "Greater"; break;
 280     case AsmToken::GreaterEqual:   OS << "GreaterEqual"; break;
 281     case AsmToken::GreaterGreater: OS << "GreaterGreater"; break;
 282     case AsmToken::Hash:           OS << "Hash"; break;
 283     case AsmToken::LBrac:          OS << "LBrac"; break;
 284     case AsmToken::LCurly:         OS << "LCurly"; break;
 285     case AsmToken::LParen:         OS << "LParen"; break;
 286     case AsmToken::Less:           OS << "Less"; break;
 287     case AsmToken::LessEqual:      OS << "LessEqual"; break;
 288     case AsmToken::LessGreater:    OS << "LessGreater"; break;
 289     case AsmToken::LessLess:       OS << "LessLess"; break;
 290     case AsmToken::Minus:          OS << "Minus"; break;
 291     case AsmToken::Percent:        OS << "Percent"; break;
 292     case AsmToken::Pipe:           OS << "Pipe"; break;
 293     case AsmToken::PipePipe:       OS << "PipePipe"; break;
 294     case AsmToken::Plus:           OS << "Plus"; break;
 295     case AsmToken::RBrac:          OS << "RBrac"; break;
 296     case AsmToken::RCurly:         OS << "RCurly"; break;
 297     case AsmToken::RParen:         OS << "RParen"; break;
 298     case AsmToken::Slash:          OS << "Slash"; break;
 299     case AsmToken::Star:           OS << "Star"; break;
 300     case AsmToken::Tilde:          OS << "Tilde"; break;
 301     case AsmToken::PercentCall16:
 302       OS << "PercentCall16";
 303       break;
 304     case AsmToken::PercentCall_Hi:
 305       OS << "PercentCall_Hi";
 306       break;
 307     case AsmToken::PercentCall_Lo:
 308       OS << "PercentCall_Lo";
 309       break;
 310     case AsmToken::PercentDtprel_Hi:
 311       OS << "PercentDtprel_Hi";
 312       break;
 313     case AsmToken::PercentDtprel_Lo:
 314       OS << "PercentDtprel_Lo";
 315       break;
 316     case AsmToken::PercentGot:
 317       OS << "PercentGot";
 318       break;
 319     case AsmToken::PercentGot_Disp:
 320       OS << "PercentGot_Disp";
 321       break;
 322     case AsmToken::PercentGot_Hi:
 323       OS << "PercentGot_Hi";
 324       break;
 325     case AsmToken::PercentGot_Lo:
 326       OS << "PercentGot_Lo";
 327       break;
 328     case AsmToken::PercentGot_Ofst:
 329       OS << "PercentGot_Ofst";
 330       break;
 331     case AsmToken::PercentGot_Page:
 332       OS << "PercentGot_Page";
 333       break;
 334     case AsmToken::PercentGottprel:
 335       OS << "PercentGottprel";
 336       break;
 337     case AsmToken::PercentGp_Rel:
 338       OS << "PercentGp_Rel";
 339       break;
 340     case AsmToken::PercentHi:
 341       OS << "PercentHi";
 342       break;
 343     case AsmToken::PercentHigher:
 344       OS << "PercentHigher";
 345       break;
 346     case AsmToken::PercentHighest:
 347       OS << "PercentHighest";
 348       break;
 349     case AsmToken::PercentLo:
 350       OS << "PercentLo";
 351       break;
 352     case AsmToken::PercentNeg:
 353       OS << "PercentNeg";
 354       break;
 355     case AsmToken::PercentPcrel_Hi:
 356       OS << "PercentPcrel_Hi";
 357       break;
 358     case AsmToken::PercentPcrel_Lo:
 359       OS << "PercentPcrel_Lo";
 360       break;
 361     case AsmToken::PercentTlsgd:
 362       OS << "PercentTlsgd";
 363       break;
 364     case AsmToken::PercentTlsldm:
 365       OS << "PercentTlsldm";
 366       break;
 367     case AsmToken::PercentTprel_Hi:
 368       OS << "PercentTprel_Hi";
 369       break;
 370     case AsmToken::PercentTprel_Lo:
 371       OS << "PercentTprel_Lo";
 372       break;
 373     }
 374
 375     // Print the token string.
 376     OS << " (\"";
 377     OS.write_escaped(Tok.getString());
 378     OS << "\")\n";
 379   }
 380
 381   return Error;
 382 }
 383
 384 static int fillCommandLineSymbols(MCAsmParser &Parser) {
 385   for (auto &I: DefineSymbol) {
 386     auto Pair = StringRef(I).split('=');
 387     auto Sym = Pair.first;
 388     auto Val = Pair.second;
 389
 390     if (Sym.empty() || Val.empty()) {
 391       errs() << "error: defsym must be of the form: sym=value: " << I << "\n";
 392       return 1;
 393     }
 394     int64_t Value;
 395     if (Val.getAsInteger(0, Value)) {
 396       errs() << "error: Value is not an integer: " << Val << "\n";
 397       return 1;
 398     }
 399     Parser.getContext().setSymbolValue(Parser.getStreamer(), Sym, Value);
 400   }
 401   return 0;
 402 }
 403
 404 static int AssembleInput(const char *ProgName, const Target *TheTarget,
 405                          SourceMgr &SrcMgr, MCContext &Ctx, MCStreamer &Str,
 406                          MCAsmInfo &MAI, MCSubtargetInfo &STI,
 407                          MCInstrInfo &MCII, MCTargetOptions &MCOptions) {
 408   std::unique_ptr<MCAsmParser> Parser(
 409       createMCAsmParser(SrcMgr, Ctx, Str, MAI));
 410   std::unique_ptr<MCTargetAsmParser> TAP(
 411       TheTarget->createMCAsmParser(STI, *Parser, MCII, MCOptions));
 412
 413   if (!TAP) {
 414     errs() << ProgName
 415            << ": error: this target does not support assembly parsing.\n";
 416     return 1;
 417   }
 418
 419   int SymbolResult = fillCommandLineSymbols(*Parser);
 420   if(SymbolResult)
 421     return SymbolResult;
 422   Parser->setShowParsedOperands(ShowInstOperands);
 423   Parser->setTargetParser(*TAP);
 424
 425   int Res = Parser->Run(NoInitialTextSection);
 426
 427   return Res;
 428 }
 429
 430 int main(int argc, char **argv) {
 431   // Print a stack trace if we signal out.
 432   sys::PrintStackTraceOnErrorSignal(argv[0]);
 433   PrettyStackTraceProgram X(argc, argv);
 434   llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
 435
 436   // Initialize targets and assembly printers/parsers.
 437   llvm::InitializeAllTargetInfos();
 438   llvm::InitializeAllTargetMCs();
 439   llvm::InitializeAllAsmParsers();
 440   llvm::InitializeAllDisassemblers();
 441
 442   // Register the target printer for --version.
 443   cl::AddExtraVersionPrinter(TargetRegistry::printRegisteredTargetsForVersion);
 444
 445   cl::ParseCommandLineOptions(argc, argv, "llvm machine code playground\n");
 446   MCTargetOptions MCOptions = InitMCTargetOptionsFromFlags();
 447   TripleName = Triple::normalize(TripleName);
 448   setDwarfDebugFlags(argc, argv);
 449
 450   setDwarfDebugProducer();
 451
 452   const char *ProgName = argv[0];
 453   const Target *TheTarget = GetTarget(ProgName);
 454   if (!TheTarget)
 455     return 1;
 456   // Now that GetTarget() has (potentially) replaced TripleName, it's safe to
 457   // construct the Triple object.
 458   Triple TheTriple(TripleName);
 459
 460   ErrorOr<std::unique_ptr<MemoryBuffer>> BufferPtr =
 461       MemoryBuffer::getFileOrSTDIN(InputFilename);
 462   if (std::error_code EC = BufferPtr.getError()) {
 463     errs() << InputFilename << ": " << EC.message() << '\n';
 464     return 1;
 465   }
 466   MemoryBuffer *Buffer = BufferPtr->get();
 467
 468   SourceMgr SrcMgr;
 469
 470   // Tell SrcMgr about this buffer, which is what the parser will pick up.
 471   SrcMgr.AddNewSourceBuffer(std::move(*BufferPtr), SMLoc());
 472
 473   // Record the location of the include directories so that the lexer can find
 474   // it later.
 475   SrcMgr.setIncludeDirs(IncludeDirs);
 476
 477   std::unique_ptr<MCRegisterInfo> MRI(TheTarget->createMCRegInfo(TripleName));
 478   assert(MRI && "Unable to create target register info!");
 479
 480   std::unique_ptr<MCAsmInfo> MAI(TheTarget->createMCAsmInfo(*MRI, TripleName));
 481   assert(MAI && "Unable to create target asm info!");
 482
 483   MAI->setRelaxELFRelocations(RelaxELFRel);
 484
 485   if (CompressDebugSections != DebugCompressionType::None) {
 486     if (!zlib::isAvailable()) {
 487       errs() << ProgName
 488              << ": build tools with zlib to enable -compress-debug-sections";
 489       return 1;
 490     }
 491     MAI->setCompressDebugSections(CompressDebugSections);
 492   }
 493   MAI->setPreserveAsmComments(PreserveComments);
 494
 495   // FIXME: This is not pretty. MCContext has a ptr to MCObjectFileInfo and
 496   // MCObjectFileInfo needs a MCContext reference in order to initialize itself.
 497   MCObjectFileInfo MOFI;
 498   MCContext Ctx(MAI.get(), MRI.get(), &MOFI, &SrcMgr);
 499   MOFI.InitMCObjectFileInfo(TheTriple, PIC, Ctx, LargeCodeModel);
 500
 501   if (SaveTempLabels)
 502     Ctx.setAllowTemporaryLabels(false);
 503
 504   Ctx.setGenDwarfForAssembly(GenDwarfForAssembly);
 505   // Default to 4 for dwarf version.
 506   unsigned DwarfVersion = MCOptions.DwarfVersion ? MCOptions.DwarfVersion : 4;
 507   if (DwarfVersion < 2 || DwarfVersion > 5) {
 508     errs() << ProgName << ": Dwarf version " << DwarfVersion
 509            << " is not supported." << '\n';
 510     return 1;
 511   }
 512   Ctx.setDwarfVersion(DwarfVersion);
 513   if (!DwarfDebugFlags.empty())
 514     Ctx.setDwarfDebugFlags(StringRef(DwarfDebugFlags));
 515   if (!DwarfDebugProducer.empty())
 516     Ctx.setDwarfDebugProducer(StringRef(DwarfDebugProducer));
 517   if (!DebugCompilationDir.empty())
 518     Ctx.setCompilationDir(DebugCompilationDir);
 519   else {
 520     // If no compilation dir is set, try to use the current directory.
 521     SmallString<128> CWD;
 522     if (!sys::fs::current_path(CWD))
 523       Ctx.setCompilationDir(CWD);
 524   }
 525   if (!MainFileName.empty())
 526     Ctx.setMainFileName(MainFileName);
 527
 528   // Package up features to be passed to target/subtarget
 529   std::string FeaturesStr;
 530   if (MAttrs.size()) {
 531     SubtargetFeatures Features;
 532     for (unsigned i = 0; i != MAttrs.size(); ++i)
 533       Features.AddFeature(MAttrs[i]);
 534     FeaturesStr = Features.getString();
 535   }
 536
 537   std::unique_ptr<tool_output_file> Out = GetOutputStream();
 538   if (!Out)
 539     return 1;
 540
 541   std::unique_ptr<buffer_ostream> BOS;
 542   raw_pwrite_stream *OS = &Out->os();
 543   std::unique_ptr<MCStreamer> Str;
 544
 545   std::unique_ptr<MCInstrInfo> MCII(TheTarget->createMCInstrInfo());
 546   std::unique_ptr<MCSubtargetInfo> STI(
 547       TheTarget->createMCSubtargetInfo(TripleName, MCPU, FeaturesStr));
 548
 549   MCInstPrinter *IP = nullptr;
 550   if (FileType == OFT_AssemblyFile) {
 551     IP = TheTarget->createMCInstPrinter(Triple(TripleName), OutputAsmVariant,
 552                                         *MAI, *MCII, *MRI);
 553
 554     if (!IP) {
 555       errs()
 556           << "error: unable to create instruction printer for target triple '"
 557           << TheTriple.normalize() << "' with assembly variant "
 558           << OutputAsmVariant << ".\n";
 559       return 1;
 560     }
 561
 562     // Set the display preference for hex vs. decimal immediates.
 563     IP->setPrintImmHex(PrintImmHex);
 564
 565     // Set up the AsmStreamer.
 566     MCCodeEmitter *CE = nullptr;
 567     MCAsmBackend *MAB = nullptr;
 568     if (ShowEncoding) {
 569       CE = TheTarget->createMCCodeEmitter(*MCII, *MRI, Ctx);
 570       MAB = TheTarget->createMCAsmBackend(*MRI, TripleName, MCPU, MCOptions);
 571     }
 572     auto FOut = llvm::make_unique<formatted_raw_ostream>(*OS);
 573     Str.reset(TheTarget->createAsmStreamer(
 574         Ctx, std::move(FOut), /*asmverbose*/ true,
 575         /*useDwarfDirectory*/ true, IP, CE, MAB, ShowInst));
 576
 577   } else if (FileType == OFT_Null) {
 578     Str.reset(TheTarget->createNullStreamer(Ctx));
 579   } else {
 580     assert(FileType == OFT_ObjectFile && "Invalid file type!");
 581
 582     // Don't waste memory on names of temp labels.
 583     Ctx.setUseNamesOnTempLabels(false);
 584
 585     if (!Out->os().supportsSeeking()) {
 586       BOS = make_unique<buffer_ostream>(Out->os());
 587       OS = BOS.get();
 588     }
 589
 590     MCCodeEmitter *CE = TheTarget->createMCCodeEmitter(*MCII, *MRI, Ctx);
 591     MCAsmBackend *MAB = TheTarget->createMCAsmBackend(*MRI, TripleName, MCPU,
 592                                                       MCOptions);
 593     Str.reset(TheTarget->createMCObjectStreamer(
 594         TheTriple, Ctx, *MAB, *OS, CE, *STI, MCOptions.MCRelaxAll,
 595         MCOptions.MCIncrementalLinkerCompatible,
 596         /*DWARFMustBeAtTheEnd*/ false));
 597     if (NoExecStack)
 598       Str->InitSections(true);
 599   }
 600
 601   int Res = 1;
 602   bool disassemble = false;
 603   switch (Action) {
 604   case AC_AsLex:
 605     Res = AsLexInput(SrcMgr, *MAI, Out->os());
 606     break;
 607   case AC_Assemble:
 608     Res = AssembleInput(ProgName, TheTarget, SrcMgr, Ctx, *Str, *MAI, *STI,
 609                         *MCII, MCOptions);
 610     break;
 611   case AC_MDisassemble:
 612     assert(IP && "Expected assembly output");
 613     IP->setUseMarkup(1);
 614     disassemble = true;
 615     break;
 616   case AC_Disassemble:
 617     disassemble = true;
 618     break;
 619   }
 620   if (disassemble)
 621     Res = Disassembler::disassemble(*TheTarget, TripleName, *STI, *Str,
 622                                     *Buffer, SrcMgr, Out->os());
 623
 624   // Keep output if no errors.
 625   if (Res == 0) Out->keep();
 626   return Res;
 627 }