tools/dsymutil/dsymutil.cpp

   1 //===- dsymutil.cpp - Debug info dumping utility for llvm -----------------===//
   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 program is a utility that aims to be a dropin replacement for Darwin's
  10 // dsymutil.
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "dsymutil.h"
  14 #include "BinaryHolder.h"
  15 #include "CFBundle.h"
  16 #include "DebugMap.h"
  17 #include "LinkUtils.h"
  18 #include "MachOUtils.h"
  19 #include "llvm/ADT/SmallString.h"
  20 #include "llvm/ADT/SmallVector.h"
  21 #include "llvm/ADT/StringExtras.h"
  22 #include "llvm/ADT/StringRef.h"
  23 #include "llvm/ADT/StringSwitch.h"
  24 #include "llvm/ADT/Triple.h"
  25 #include "llvm/DebugInfo/DIContext.h"
  26 #include "llvm/DebugInfo/DWARF/DWARFContext.h"
  27 #include "llvm/DebugInfo/DWARF/DWARFVerifier.h"
  28 #include "llvm/Object/Binary.h"
  29 #include "llvm/Object/MachO.h"
  30 #include "llvm/Option/Arg.h"
  31 #include "llvm/Option/ArgList.h"
  32 #include "llvm/Option/Option.h"
  33 #include "llvm/Support/CommandLine.h"
  34 #include "llvm/Support/FileSystem.h"
  35 #include "llvm/Support/InitLLVM.h"
  36 #include "llvm/Support/ManagedStatic.h"
  37 #include "llvm/Support/Path.h"
  38 #include "llvm/Support/TargetSelect.h"
  39 #include "llvm/Support/ThreadPool.h"
  40 #include "llvm/Support/WithColor.h"
  41 #include "llvm/Support/raw_ostream.h"
  42 #include "llvm/Support/thread.h"
  43 #include <algorithm>
  44 #include <cstdint>
  45 #include <cstdlib>
  46 #include <string>
  47 #include <system_error>
  48
  49 using namespace llvm;
  50 using namespace llvm::dsymutil;
  51 using namespace object;
  52
  53 namespace {
  54 enum ID {
  55   OPT_INVALID = 0, // This is not an option ID.
  56 #define OPTION(PREFIX, NAME, ID, KIND, GROUP, ALIAS, ALIASARGS, FLAGS, PARAM,  \
  57                HELPTEXT, METAVAR, VALUES)                                      \
  58   OPT_##ID,
  59 #include "Options.inc"
  60 #undef OPTION
  61 };
  62
  63 #define PREFIX(NAME, VALUE) const char *const NAME[] = VALUE;
  64 #include "Options.inc"
  65 #undef PREFIX
  66
  67 const opt::OptTable::Info InfoTable[] = {
  68 #define OPTION(PREFIX, NAME, ID, KIND, GROUP, ALIAS, ALIASARGS, FLAGS, PARAM,  \
  69                HELPTEXT, METAVAR, VALUES)                                      \
  70   {                                                                            \
  71       PREFIX,      NAME,      HELPTEXT,                                        \
  72       METAVAR,     OPT_##ID,  opt::Option::KIND##Class,                        \
  73       PARAM,       FLAGS,     OPT_##GROUP,                                     \
  74       OPT_##ALIAS, ALIASARGS, VALUES},
  75 #include "Options.inc"
  76 #undef OPTION
  77 };
  78
  79 class DsymutilOptTable : public opt::OptTable {
  80 public:
  81   DsymutilOptTable() : OptTable(InfoTable) {}
  82 };
  83 } // namespace
  84
  85 struct DsymutilOptions {
  86   bool DumpDebugMap = false;
  87   bool DumpStab = false;
  88   bool Flat = false;
  89   bool InputIsYAMLDebugMap = false;
  90   bool PaperTrailWarnings = false;
  91   bool Verify = false;
  92   std::string SymbolMap;
  93   std::string OutputFile;
  94   std::string Toolchain;
  95   std::vector<std::string> Archs;
  96   std::vector<std::string> InputFiles;
  97   unsigned NumThreads;
  98   dsymutil::LinkOptions LinkOpts;
  99 };
 100
 101 /// Return a list of input files. This function has logic for dealing with the
 102 /// special case where we might have dSYM bundles as input. The function
 103 /// returns an error when the directory structure doesn't match that of a dSYM
 104 /// bundle.
 105 static Expected<std::vector<std::string>> getInputs(opt::InputArgList &Args,
 106                                                     bool DsymAsInput) {
 107   std::vector<std::string> InputFiles;
 108   for (auto *File : Args.filtered(OPT_INPUT))
 109     InputFiles.push_back(File->getValue());
 110
 111   if (!DsymAsInput)
 112     return InputFiles;
 113
 114   // If we are updating, we might get dSYM bundles as input.
 115   std::vector<std::string> Inputs;
 116   for (const auto &Input : InputFiles) {
 117     if (!sys::fs::is_directory(Input)) {
 118       Inputs.push_back(Input);
 119       continue;
 120     }
 121
 122     // Make sure that we're dealing with a dSYM bundle.
 123     SmallString<256> BundlePath(Input);
 124     sys::path::append(BundlePath, "Contents", "Resources", "DWARF");
 125     if (!sys::fs::is_directory(BundlePath))
 126       return make_error<StringError>(
 127           Input + " is a directory, but doesn't look like a dSYM bundle.",
 128           inconvertibleErrorCode());
 129
 130     // Create a directory iterator to iterate over all the entries in the
 131     // bundle.
 132     std::error_code EC;
 133     sys::fs::directory_iterator DirIt(BundlePath, EC);
 134     sys::fs::directory_iterator DirEnd;
 135     if (EC)
 136       return errorCodeToError(EC);
 137
 138     // Add each entry to the list of inputs.
 139     while (DirIt != DirEnd) {
 140       Inputs.push_back(DirIt->path());
 141       DirIt.increment(EC);
 142       if (EC)
 143         return errorCodeToError(EC);
 144     }
 145   }
 146   return Inputs;
 147 }
 148
 149 // Verify that the given combination of options makes sense.
 150 static Error verifyOptions(const DsymutilOptions &Options) {
 151   if (Options.LinkOpts.Update &&
 152       std::find(Options.InputFiles.begin(), Options.InputFiles.end(), "-") !=
 153           Options.InputFiles.end()) {
 154     // FIXME: We cannot use stdin for an update because stdin will be
 155     // consumed by the BinaryHolder during the debugmap parsing, and
 156     // then we will want to consume it again in DwarfLinker. If we
 157     // used a unique BinaryHolder object that could cache multiple
 158     // binaries this restriction would go away.
 159     return make_error<StringError>(
 160         "standard input cannot be used as input for a dSYM update.",
 161         errc::invalid_argument);
 162   }
 163
 164   if (!Options.Flat && Options.OutputFile == "-")
 165     return make_error<StringError>(
 166         "cannot emit to standard output without --flat.",
 167         errc::invalid_argument);
 168
 169   if (Options.InputFiles.size() > 1 && Options.Flat &&
 170       !Options.OutputFile.empty())
 171     return make_error<StringError>(
 172         "cannot use -o with multiple inputs in flat mode.",
 173         errc::invalid_argument);
 174
 175   if (Options.PaperTrailWarnings && Options.InputIsYAMLDebugMap)
 176     return make_error<StringError>(
 177         "paper trail warnings are not supported for YAML input.",
 178         errc::invalid_argument);
 179
 180   return Error::success();
 181 }
 182
 183 static Expected<AccelTableKind> getAccelTableKind(opt::InputArgList &Args) {
 184   if (opt::Arg *Accelerator = Args.getLastArg(OPT_accelerator)) {
 185     StringRef S = Accelerator->getValue();
 186     if (S == "Apple")
 187       return AccelTableKind::Apple;
 188     if (S == "Dwarf")
 189       return AccelTableKind::Dwarf;
 190     if (S == "Default")
 191       return AccelTableKind::Default;
 192     return make_error<StringError>(
 193         "invalid accelerator type specified: '" + S +
 194             "'. Support values are 'Apple', 'Dwarf' and 'Default'.",
 195         inconvertibleErrorCode());
 196   }
 197   return AccelTableKind::Default;
 198 }
 199
 200 /// Parses the command line options into the LinkOptions struct and performs
 201 /// some sanity checking. Returns an error in case the latter fails.
 202 static Expected<DsymutilOptions> getOptions(opt::InputArgList &Args) {
 203   DsymutilOptions Options;
 204
 205   Options.DumpDebugMap = Args.hasArg(OPT_dump_debug_map);
 206   Options.DumpStab = Args.hasArg(OPT_symtab);
 207   Options.Flat = Args.hasArg(OPT_flat);
 208   Options.InputIsYAMLDebugMap = Args.hasArg(OPT_yaml_input);
 209   Options.PaperTrailWarnings = Args.hasArg(OPT_papertrail);
 210   Options.Verify = Args.hasArg(OPT_verify);
 211
 212   Options.LinkOpts.Minimize = Args.hasArg(OPT_minimize);
 213   Options.LinkOpts.NoODR = Args.hasArg(OPT_no_odr);
 214   Options.LinkOpts.NoOutput = Args.hasArg(OPT_no_output);
 215   Options.LinkOpts.NoTimestamp = Args.hasArg(OPT_no_swiftmodule_timestamp);
 216   Options.LinkOpts.Update = Args.hasArg(OPT_update);
 217   Options.LinkOpts.Verbose = Args.hasArg(OPT_verbose);
 218
 219   if (Expected<AccelTableKind> AccelKind = getAccelTableKind(Args)) {
 220     Options.LinkOpts.TheAccelTableKind = *AccelKind;
 221   } else {
 222     return AccelKind.takeError();
 223   }
 224
 225   if (opt::Arg *SymbolMap = Args.getLastArg(OPT_symbolmap))
 226     Options.SymbolMap = SymbolMap->getValue();
 227
 228   if (Args.hasArg(OPT_symbolmap))
 229     Options.LinkOpts.Update = true;
 230
 231   if (Expected<std::vector<std::string>> InputFiles =
 232           getInputs(Args, Options.LinkOpts.Update)) {
 233     Options.InputFiles = std::move(*InputFiles);
 234   } else {
 235     return InputFiles.takeError();
 236   }
 237
 238   for (auto *Arch : Args.filtered(OPT_arch))
 239     Options.Archs.push_back(Arch->getValue());
 240
 241   if (opt::Arg *OsoPrependPath = Args.getLastArg(OPT_oso_prepend_path))
 242     Options.LinkOpts.PrependPath = OsoPrependPath->getValue();
 243
 244   if (opt::Arg *OutputFile = Args.getLastArg(OPT_output))
 245     Options.OutputFile = OutputFile->getValue();
 246
 247   if (opt::Arg *Toolchain = Args.getLastArg(OPT_toolchain))
 248     Options.Toolchain = Toolchain->getValue();
 249
 250   if (Args.hasArg(OPT_assembly))
 251     Options.LinkOpts.FileType = OutputFileType::Assembly;
 252
 253   if (opt::Arg *NumThreads = Args.getLastArg(OPT_threads))
 254     Options.LinkOpts.Threads = atoi(NumThreads->getValue());
 255   else
 256     Options.LinkOpts.Threads = thread::hardware_concurrency();
 257
 258   if (Options.DumpDebugMap || Options.LinkOpts.Verbose)
 259     Options.LinkOpts.Threads = 1;
 260
 261   if (getenv("RC_DEBUG_OPTIONS"))
 262     Options.PaperTrailWarnings = true;
 263
 264   if (Error E = verifyOptions(Options))
 265     return std::move(E);
 266   return Options;
 267 }
 268
 269 static Error createPlistFile(StringRef Bin, StringRef BundleRoot,
 270                              StringRef Toolchain) {
 271   // Create plist file to write to.
 272   SmallString<128> InfoPlist(BundleRoot);
 273   sys::path::append(InfoPlist, "Contents/Info.plist");
 274   std::error_code EC;
 275   raw_fd_ostream PL(InfoPlist, EC, sys::fs::OF_Text);
 276   if (EC)
 277     return make_error<StringError>(
 278         "cannot create Plist: " + toString(errorCodeToError(EC)), EC);
 279
 280   CFBundleInfo BI = getBundleInfo(Bin);
 281
 282   if (BI.IDStr.empty()) {
 283     StringRef BundleID = *sys::path::rbegin(BundleRoot);
 284     if (sys::path::extension(BundleRoot) == ".dSYM")
 285       BI.IDStr = sys::path::stem(BundleID);
 286     else
 287       BI.IDStr = BundleID;
 288   }
 289
 290   // Print out information to the plist file.
 291   PL << "<?xml version=\"1.0\" encoding=\"UTF-8\"\?>\n"
 292      << "<!DOCTYPE plist PUBLIC \"-//Apple Computer//DTD PLIST 1.0//EN\" "
 293      << "\"http://www.apple.com/DTDs/PropertyList-1.0.dtd\">\n"
 294      << "<plist version=\"1.0\">\n"
 295      << "\t<dict>\n"
 296      << "\t\t<key>CFBundleDevelopmentRegion</key>\n"
 297      << "\t\t<string>English</string>\n"
 298      << "\t\t<key>CFBundleIdentifier</key>\n"
 299      << "\t\t<string>com.apple.xcode.dsym." << BI.IDStr << "</string>\n"
 300      << "\t\t<key>CFBundleInfoDictionaryVersion</key>\n"
 301      << "\t\t<string>6.0</string>\n"
 302      << "\t\t<key>CFBundlePackageType</key>\n"
 303      << "\t\t<string>dSYM</string>\n"
 304      << "\t\t<key>CFBundleSignature</key>\n"
 305      << "\t\t<string>\?\?\?\?</string>\n";
 306
 307   if (!BI.OmitShortVersion()) {
 308     PL << "\t\t<key>CFBundleShortVersionString</key>\n";
 309     PL << "\t\t<string>";
 310     printHTMLEscaped(BI.ShortVersionStr, PL);
 311     PL << "</string>\n";
 312   }
 313
 314   PL << "\t\t<key>CFBundleVersion</key>\n";
 315   PL << "\t\t<string>";
 316   printHTMLEscaped(BI.VersionStr, PL);
 317   PL << "</string>\n";
 318
 319   if (!Toolchain.empty()) {
 320     PL << "\t\t<key>Toolchain</key>\n";
 321     PL << "\t\t<string>";
 322     printHTMLEscaped(Toolchain, PL);
 323     PL << "</string>\n";
 324   }
 325
 326   PL << "\t</dict>\n"
 327      << "</plist>\n";
 328
 329   PL.close();
 330   return Error::success();
 331 }
 332
 333 static Error createBundleDir(StringRef BundleBase) {
 334   SmallString<128> Bundle(BundleBase);
 335   sys::path::append(Bundle, "Contents", "Resources", "DWARF");
 336   if (std::error_code EC =
 337           create_directories(Bundle.str(), true, sys::fs::perms::all_all))
 338     return make_error<StringError>(
 339         "cannot create bundle: " + toString(errorCodeToError(EC)), EC);
 340
 341   return Error::success();
 342 }
 343
 344 static bool verify(StringRef OutputFile, StringRef Arch, bool Verbose) {
 345   if (OutputFile == "-") {
 346     WithColor::warning() << "verification skipped for " << Arch
 347                          << "because writing to stdout.\n";
 348     return true;
 349   }
 350
 351   Expected<OwningBinary<Binary>> BinOrErr = createBinary(OutputFile);
 352   if (!BinOrErr) {
 353     WithColor::error() << OutputFile << ": " << toString(BinOrErr.takeError());
 354     return false;
 355   }
 356
 357   Binary &Binary = *BinOrErr.get().getBinary();
 358   if (auto *Obj = dyn_cast<MachOObjectFile>(&Binary)) {
 359     raw_ostream &os = Verbose ? errs() : nulls();
 360     os << "Verifying DWARF for architecture: " << Arch << "\n";
 361     std::unique_ptr<DWARFContext> DICtx = DWARFContext::create(*Obj);
 362     DIDumpOptions DumpOpts;
 363     bool success = DICtx->verify(os, DumpOpts.noImplicitRecursion());
 364     if (!success)
 365       WithColor::error() << "verification failed for " << Arch << '\n';
 366     return success;
 367   }
 368
 369   return false;
 370 }
 371
 372 namespace {
 373 struct OutputLocation {
 374   OutputLocation(std::string DWARFFile, Optional<std::string> ResourceDir = {})
 375       : DWARFFile(DWARFFile), ResourceDir(ResourceDir) {}
 376   /// This method is a workaround for older compilers.
 377   Optional<std::string> getResourceDir() const { return ResourceDir; }
 378   std::string DWARFFile;
 379   Optional<std::string> ResourceDir;
 380 };
 381 } // namespace
 382
 383 static Expected<OutputLocation>
 384 getOutputFileName(StringRef InputFile, const DsymutilOptions &Options) {
 385   if (Options.OutputFile == "-")
 386     return OutputLocation(Options.OutputFile);
 387
 388   // When updating, do in place replacement.
 389   if (Options.OutputFile.empty() &&
 390       (Options.LinkOpts.Update || !Options.SymbolMap.empty()))
 391     return OutputLocation(InputFile);
 392
 393   // If a flat dSYM has been requested, things are pretty simple.
 394   if (Options.Flat) {
 395     if (Options.OutputFile.empty()) {
 396       if (InputFile == "-")
 397         return OutputLocation{"a.out.dwarf", {}};
 398       return OutputLocation((InputFile + ".dwarf").str());
 399     }
 400
 401     return OutputLocation(Options.OutputFile);
 402   }
 403
 404   // We need to create/update a dSYM bundle.
 405   // A bundle hierarchy looks like this:
 406   //   <bundle name>.dSYM/
 407   //       Contents/
 408   //          Info.plist
 409   //          Resources/
 410   //             DWARF/
 411   //                <DWARF file(s)>
 412   std::string DwarfFile = InputFile == "-" ? StringRef("a.out") : InputFile;
 413   SmallString<128> Path(Options.OutputFile);
 414   if (Path.empty())
 415     Path = DwarfFile + ".dSYM";
 416   if (!Options.LinkOpts.NoOutput) {
 417     if (auto E = createBundleDir(Path))
 418       return std::move(E);
 419     if (auto E = createPlistFile(DwarfFile, Path, Options.Toolchain))
 420       return std::move(E);
 421   }
 422
 423   sys::path::append(Path, "Contents", "Resources");
 424   std::string ResourceDir = Path.str();
 425   sys::path::append(Path, "DWARF", sys::path::filename(DwarfFile));
 426   return OutputLocation(Path.str(), ResourceDir);
 427 }
 428
 429 int main(int argc, char **argv) {
 430   InitLLVM X(argc, argv);
 431
 432   // Parse arguments.
 433   DsymutilOptTable T;
 434   unsigned MAI;
 435   unsigned MAC;
 436   ArrayRef<const char *> ArgsArr = makeArrayRef(argv + 1, argc - 1);
 437   opt::InputArgList Args = T.ParseArgs(ArgsArr, MAI, MAC);
 438
 439   void *P = (void *)(intptr_t)getOutputFileName;
 440   std::string SDKPath = sys::fs::getMainExecutable(argv[0], P);
 441   SDKPath = sys::path::parent_path(SDKPath);
 442
 443   if (Args.hasArg(OPT_help)) {
 444     T.PrintHelp(
 445         outs(), (std::string(argv[0]) + " [options] <input files>").c_str(),
 446         "manipulate archived DWARF debug symbol files.\n\n"
 447         "dsymutil links the DWARF debug information found in the object files\n"
 448         "for the executable <input file> by using debug symbols information\n"
 449         "contained in its symbol table.\n",
 450         false);
 451     return 0;
 452   }
 453
 454   if (Args.hasArg(OPT_version)) {
 455     cl::PrintVersionMessage();
 456     return 0;
 457   }
 458
 459   auto OptionsOrErr = getOptions(Args);
 460   if (!OptionsOrErr) {
 461     WithColor::error() << toString(OptionsOrErr.takeError());
 462     return 1;
 463   }
 464
 465   auto &Options = *OptionsOrErr;
 466
 467   InitializeAllTargetInfos();
 468   InitializeAllTargetMCs();
 469   InitializeAllTargets();
 470   InitializeAllAsmPrinters();
 471
 472   for (const auto &Arch : Options.Archs)
 473     if (Arch != "*" && Arch != "all" &&
 474         !object::MachOObjectFile::isValidArch(Arch)) {
 475       WithColor::error() << "unsupported cpu architecture: '" << Arch << "'\n";
 476       return 1;
 477     }
 478
 479   SymbolMapLoader SymMapLoader(Options.SymbolMap);
 480
 481   for (auto &InputFile : Options.InputFiles) {
 482     // Dump the symbol table for each input file and requested arch
 483     if (Options.DumpStab) {
 484       if (!dumpStab(InputFile, Options.Archs, Options.LinkOpts.PrependPath))
 485         return 1;
 486       continue;
 487     }
 488
 489     auto DebugMapPtrsOrErr =
 490         parseDebugMap(InputFile, Options.Archs, Options.LinkOpts.PrependPath,
 491                       Options.PaperTrailWarnings, Options.LinkOpts.Verbose,
 492                       Options.InputIsYAMLDebugMap);
 493
 494     if (auto EC = DebugMapPtrsOrErr.getError()) {
 495       WithColor::error() << "cannot parse the debug map for '" << InputFile
 496                          << "': " << EC.message() << '\n';
 497       return 1;
 498     }
 499
 500     if (Options.LinkOpts.Update) {
 501       // The debug map should be empty. Add one object file corresponding to
 502       // the input file.
 503       for (auto &Map : *DebugMapPtrsOrErr)
 504         Map->addDebugMapObject(InputFile,
 505                                sys::TimePoint<std::chrono::seconds>());
 506     }
 507
 508     // Ensure that the debug map is not empty (anymore).
 509     if (DebugMapPtrsOrErr->empty()) {
 510       WithColor::error() << "no architecture to link\n";
 511       return 1;
 512     }
 513
 514     // Shared a single binary holder for all the link steps.
 515     BinaryHolder BinHolder;
 516
 517     unsigned ThreadCount =
 518         std::min<unsigned>(Options.LinkOpts.Threads, DebugMapPtrsOrErr->size());
 519     ThreadPool Threads(ThreadCount);
 520
 521     // If there is more than one link to execute, we need to generate
 522     // temporary files.
 523     const bool NeedsTempFiles =
 524         !Options.DumpDebugMap && (Options.OutputFile != "-") &&
 525         (DebugMapPtrsOrErr->size() != 1 || Options.LinkOpts.Update);
 526     const bool Verify = Options.Verify && !Options.LinkOpts.NoOutput;
 527
 528     SmallVector<MachOUtils::ArchAndFile, 4> TempFiles;
 529     std::atomic_char AllOK(1);
 530     for (auto &Map : *DebugMapPtrsOrErr) {
 531       if (Options.LinkOpts.Verbose || Options.DumpDebugMap)
 532         Map->print(outs());
 533
 534       if (Options.DumpDebugMap)
 535         continue;
 536
 537       if (!Options.SymbolMap.empty())
 538         Options.LinkOpts.Translator = SymMapLoader.Load(InputFile, *Map);
 539
 540       if (Map->begin() == Map->end())
 541         WithColor::warning()
 542             << "no debug symbols in executable (-arch "
 543             << MachOUtils::getArchName(Map->getTriple().getArchName()) << ")\n";
 544
 545       // Using a std::shared_ptr rather than std::unique_ptr because move-only
 546       // types don't work with std::bind in the ThreadPool implementation.
 547       std::shared_ptr<raw_fd_ostream> OS;
 548
 549       Expected<OutputLocation> OutputLocationOrErr =
 550           getOutputFileName(InputFile, Options);
 551       if (!OutputLocationOrErr) {
 552         WithColor::error() << toString(OutputLocationOrErr.takeError());
 553         return 1;
 554       }
 555       Options.LinkOpts.ResourceDir = OutputLocationOrErr->getResourceDir();
 556
 557       std::string OutputFile = OutputLocationOrErr->DWARFFile;
 558       if (NeedsTempFiles) {
 559         TempFiles.emplace_back(Map->getTriple().getArchName().str());
 560
 561         auto E = TempFiles.back().createTempFile();
 562         if (E) {
 563           WithColor::error() << toString(std::move(E));
 564           return 1;
 565         }
 566
 567         auto &TempFile = *(TempFiles.back().File);
 568         OS = std::make_shared<raw_fd_ostream>(TempFile.FD,
 569                                               /*shouldClose*/ false);
 570         OutputFile = TempFile.TmpName;
 571       } else {
 572         std::error_code EC;
 573         OS = std::make_shared<raw_fd_ostream>(
 574             Options.LinkOpts.NoOutput ? "-" : OutputFile, EC, sys::fs::OF_None);
 575         if (EC) {
 576           WithColor::error() << OutputFile << ": " << EC.message();
 577           return 1;
 578         }
 579       }
 580
 581       auto LinkLambda = [&, OutputFile](std::shared_ptr<raw_fd_ostream> Stream,
 582                                         LinkOptions Options) {
 583         AllOK.fetch_and(
 584             linkDwarf(*Stream, BinHolder, *Map, std::move(Options)));
 585         Stream->flush();
 586         if (Verify)
 587           AllOK.fetch_and(verify(OutputFile, Map->getTriple().getArchName(),
 588                                  Options.Verbose));
 589       };
 590
 591       // FIXME: The DwarfLinker can have some very deep recursion that can max
 592       // out the (significantly smaller) stack when using threads. We don't
 593       // want this limitation when we only have a single thread.
 594       if (ThreadCount == 1)
 595         LinkLambda(OS, Options.LinkOpts);
 596       else
 597         Threads.async(LinkLambda, OS, Options.LinkOpts);
 598     }
 599
 600     Threads.wait();
 601
 602     if (!AllOK)
 603       return 1;
 604
 605     if (NeedsTempFiles) {
 606       Expected<OutputLocation> OutputLocationOrErr =
 607           getOutputFileName(InputFile, Options);
 608       if (!OutputLocationOrErr) {
 609         WithColor::error() << toString(OutputLocationOrErr.takeError());
 610         return 1;
 611       }
 612       if (!MachOUtils::generateUniversalBinary(TempFiles,
 613                                                OutputLocationOrErr->DWARFFile,
 614                                                Options.LinkOpts, SDKPath))
 615         return 1;
 616     }
 617   }
 618
 619   return 0;
 620 }