llvm/tools/llc/llc.cpp

   1 //===-- llc.cpp - Implement the LLVM Native Code Generator ----------------===//
   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 is the llc code generator driver. It provides a convenient
  10 // command-line interface for generating native assembly-language code
  11 // or C code, given LLVM bitcode.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "llvm/ADT/STLExtras.h"
  16 #include "llvm/ADT/Triple.h"
  17 #include "llvm/Analysis/TargetLibraryInfo.h"
  18 #include "llvm/CodeGen/CommandFlags.inc"
  19 #include "llvm/CodeGen/LinkAllAsmWriterComponents.h"
  20 #include "llvm/CodeGen/LinkAllCodegenComponents.h"
  21 #include "llvm/CodeGen/MIRParser/MIRParser.h"
  22 #include "llvm/CodeGen/MachineFunctionPass.h"
  23 #include "llvm/CodeGen/MachineModuleInfo.h"
  24 #include "llvm/CodeGen/TargetPassConfig.h"
  25 #include "llvm/CodeGen/TargetSubtargetInfo.h"
  26 #include "llvm/IR/AutoUpgrade.h"
  27 #include "llvm/IR/DataLayout.h"
  28 #include "llvm/IR/DiagnosticInfo.h"
  29 #include "llvm/IR/DiagnosticPrinter.h"
  30 #include "llvm/IR/IRPrintingPasses.h"
  31 #include "llvm/IR/LLVMContext.h"
  32 #include "llvm/IR/LegacyPassManager.h"
  33 #include "llvm/IR/Module.h"
  34 #include "llvm/IR/RemarkStreamer.h"
  35 #include "llvm/IR/Verifier.h"
  36 #include "llvm/IRReader/IRReader.h"
  37 #include "llvm/InitializePasses.h"
  38 #include "llvm/MC/SubtargetFeature.h"
  39 #include "llvm/Pass.h"
  40 #include "llvm/Support/CommandLine.h"
  41 #include "llvm/Support/Debug.h"
  42 #include "llvm/Support/FileSystem.h"
  43 #include "llvm/Support/FormattedStream.h"
  44 #include "llvm/Support/Host.h"
  45 #include "llvm/Support/InitLLVM.h"
  46 #include "llvm/Support/ManagedStatic.h"
  47 #include "llvm/Support/PluginLoader.h"
  48 #include "llvm/Support/SourceMgr.h"
  49 #include "llvm/Support/TargetRegistry.h"
  50 #include "llvm/Support/TargetSelect.h"
  51 #include "llvm/Support/ToolOutputFile.h"
  52 #include "llvm/Support/WithColor.h"
  53 #include "llvm/Target/TargetMachine.h"
  54 #include "llvm/Transforms/Utils/Cloning.h"
  55 #include <memory>
  56 using namespace llvm;
  57
  58 // General options for llc.  Other pass-specific options are specified
  59 // within the corresponding llc passes, and target-specific options
  60 // and back-end code generation options are specified with the target machine.
  61 //
  62 static cl::opt<std::string>
  63 InputFilename(cl::Positional, cl::desc("<input bitcode>"), cl::init("-"));
  64
  65 static cl::opt<std::string>
  66 InputLanguage("x", cl::desc("Input language ('ir' or 'mir')"));
  67
  68 static cl::opt<std::string>
  69 OutputFilename("o", cl::desc("Output filename"), cl::value_desc("filename"));
  70
  71 static cl::opt<std::string>
  72     SplitDwarfOutputFile("split-dwarf-output",
  73                          cl::desc(".dwo output filename"),
  74                          cl::value_desc("filename"));
  75
  76 static cl::opt<unsigned>
  77 TimeCompilations("time-compilations", cl::Hidden, cl::init(1u),
  78                  cl::value_desc("N"),
  79                  cl::desc("Repeat compilation N times for timing"));
  80
  81 static cl::opt<bool>
  82 NoIntegratedAssembler("no-integrated-as", cl::Hidden,
  83                       cl::desc("Disable integrated assembler"));
  84
  85 static cl::opt<bool>
  86     PreserveComments("preserve-as-comments", cl::Hidden,
  87                      cl::desc("Preserve Comments in outputted assembly"),
  88                      cl::init(true));
  89
  90 // Determine optimization level.
  91 static cl::opt<char>
  92 OptLevel("O",
  93          cl::desc("Optimization level. [-O0, -O1, -O2, or -O3] "
  94                   "(default = '-O2')"),
  95          cl::Prefix,
  96          cl::ZeroOrMore,
  97          cl::init(' '));
  98
  99 static cl::opt<std::string>
 100 TargetTriple("mtriple", cl::desc("Override target triple for module"));
 101
 102 static cl::opt<std::string> SplitDwarfFile(
 103     "split-dwarf-file",
 104     cl::desc(
 105         "Specify the name of the .dwo file to encode in the DWARF output"));
 106
 107 static cl::opt<bool> NoVerify("disable-verify", cl::Hidden,
 108                               cl::desc("Do not verify input module"));
 109
 110 static cl::opt<bool> DisableSimplifyLibCalls("disable-simplify-libcalls",
 111                                              cl::desc("Disable simplify-libcalls"));
 112
 113 static cl::opt<bool> ShowMCEncoding("show-mc-encoding", cl::Hidden,
 114                                     cl::desc("Show encoding in .s output"));
 115
 116 static cl::opt<bool> EnableDwarfDirectory(
 117     "enable-dwarf-directory", cl::Hidden,
 118     cl::desc("Use .file directives with an explicit directory."));
 119
 120 static cl::opt<bool> AsmVerbose("asm-verbose",
 121                                 cl::desc("Add comments to directives."),
 122                                 cl::init(true));
 123
 124 static cl::opt<bool>
 125     CompileTwice("compile-twice", cl::Hidden,
 126                  cl::desc("Run everything twice, re-using the same pass "
 127                           "manager and verify the result is the same."),
 128                  cl::init(false));
 129
 130 static cl::opt<bool> DiscardValueNames(
 131     "discard-value-names",
 132     cl::desc("Discard names from Value (other than GlobalValue)."),
 133     cl::init(false), cl::Hidden);
 134
 135 static cl::list<std::string> IncludeDirs("I", cl::desc("include search path"));
 136
 137 static cl::opt<bool> RemarksWithHotness(
 138     "pass-remarks-with-hotness",
 139     cl::desc("With PGO, include profile count in optimization remarks"),
 140     cl::Hidden);
 141
 142 static cl::opt<unsigned>
 143     RemarksHotnessThreshold("pass-remarks-hotness-threshold",
 144                             cl::desc("Minimum profile count required for "
 145                                      "an optimization remark to be output"),
 146                             cl::Hidden);
 147
 148 static cl::opt<std::string>
 149     RemarksFilename("pass-remarks-output",
 150                     cl::desc("Output filename for pass remarks"),
 151                     cl::value_desc("filename"));
 152
 153 static cl::opt<std::string>
 154     RemarksPasses("pass-remarks-filter",
 155                   cl::desc("Only record optimization remarks from passes whose "
 156                            "names match the given regular expression"),
 157                   cl::value_desc("regex"));
 158
 159 static cl::opt<std::string> RemarksFormat(
 160     "pass-remarks-format",
 161     cl::desc("The format used for serializing remarks (default: YAML)"),
 162     cl::value_desc("format"), cl::init("yaml"));
 163
 164 namespace {
 165 static ManagedStatic<std::vector<std::string>> RunPassNames;
 166
 167 struct RunPassOption {
 168   void operator=(const std::string &Val) const {
 169     if (Val.empty())
 170       return;
 171     SmallVector<StringRef, 8> PassNames;
 172     StringRef(Val).split(PassNames, ',', -1, false);
 173     for (auto PassName : PassNames)
 174       RunPassNames->push_back(PassName);
 175   }
 176 };
 177 }
 178
 179 static RunPassOption RunPassOpt;
 180
 181 static cl::opt<RunPassOption, true, cl::parser<std::string>> RunPass(
 182     "run-pass",
 183     cl::desc("Run compiler only for specified passes (comma separated list)"),
 184     cl::value_desc("pass-name"), cl::ZeroOrMore, cl::location(RunPassOpt));
 185
 186 static int compileModule(char **, LLVMContext &);
 187
 188 static std::unique_ptr<ToolOutputFile> GetOutputStream(const char *TargetName,
 189                                                        Triple::OSType OS,
 190                                                        const char *ProgName) {
 191   // If we don't yet have an output filename, make one.
 192   if (OutputFilename.empty()) {
 193     if (InputFilename == "-")
 194       OutputFilename = "-";
 195     else {
 196       // If InputFilename ends in .bc or .ll, remove it.
 197       StringRef IFN = InputFilename;
 198       if (IFN.endswith(".bc") || IFN.endswith(".ll"))
 199         OutputFilename = IFN.drop_back(3);
 200       else if (IFN.endswith(".mir"))
 201         OutputFilename = IFN.drop_back(4);
 202       else
 203         OutputFilename = IFN;
 204
 205       switch (FileType) {
 206       case CGFT_AssemblyFile:
 207         if (TargetName[0] == 'c') {
 208           if (TargetName[1] == 0)
 209             OutputFilename += ".cbe.c";
 210           else if (TargetName[1] == 'p' && TargetName[2] == 'p')
 211             OutputFilename += ".cpp";
 212           else
 213             OutputFilename += ".s";
 214         } else
 215           OutputFilename += ".s";
 216         break;
 217       case CGFT_ObjectFile:
 218         if (OS == Triple::Win32)
 219           OutputFilename += ".obj";
 220         else
 221           OutputFilename += ".o";
 222         break;
 223       case CGFT_Null:
 224         OutputFilename += ".null";
 225         break;
 226       }
 227     }
 228   }
 229
 230   // Decide if we need "binary" output.
 231   bool Binary = false;
 232   switch (FileType) {
 233   case CGFT_AssemblyFile:
 234     break;
 235   case CGFT_ObjectFile:
 236   case CGFT_Null:
 237     Binary = true;
 238     break;
 239   }
 240
 241   // Open the file.
 242   std::error_code EC;
 243   sys::fs::OpenFlags OpenFlags = sys::fs::OF_None;
 244   if (!Binary)
 245     OpenFlags |= sys::fs::OF_Text;
 246   auto FDOut = std::make_unique<ToolOutputFile>(OutputFilename, EC, OpenFlags);
 247   if (EC) {
 248     WithColor::error() << EC.message() << '\n';
 249     return nullptr;
 250   }
 251
 252   return FDOut;
 253 }
 254
 255 struct LLCDiagnosticHandler : public DiagnosticHandler {
 256   bool *HasError;
 257   LLCDiagnosticHandler(bool *HasErrorPtr) : HasError(HasErrorPtr) {}
 258   bool handleDiagnostics(const DiagnosticInfo &DI) override {
 259     if (DI.getSeverity() == DS_Error)
 260       *HasError = true;
 261
 262     if (auto *Remark = dyn_cast<DiagnosticInfoOptimizationBase>(&DI))
 263       if (!Remark->isEnabled())
 264         return true;
 265
 266     DiagnosticPrinterRawOStream DP(errs());
 267     errs() << LLVMContext::getDiagnosticMessagePrefix(DI.getSeverity()) << ": ";
 268     DI.print(DP);
 269     errs() << "\n";
 270     return true;
 271   }
 272 };
 273
 274 static void InlineAsmDiagHandler(const SMDiagnostic &SMD, void *Context,
 275                                  unsigned LocCookie) {
 276   bool *HasError = static_cast<bool *>(Context);
 277   if (SMD.getKind() == SourceMgr::DK_Error)
 278     *HasError = true;
 279
 280   SMD.print(nullptr, errs());
 281
 282   // For testing purposes, we print the LocCookie here.
 283   if (LocCookie)
 284     WithColor::note() << "!srcloc = " << LocCookie << "\n";
 285 }
 286
 287 // main - Entry point for the llc compiler.
 288 //
 289 int main(int argc, char **argv) {
 290   InitLLVM X(argc, argv);
 291
 292   // Enable debug stream buffering.
 293   EnableDebugBuffering = true;
 294
 295   LLVMContext Context;
 296
 297   // Initialize targets first, so that --version shows registered targets.
 298   InitializeAllTargets();
 299   InitializeAllTargetMCs();
 300   InitializeAllAsmPrinters();
 301   InitializeAllAsmParsers();
 302
 303   // Initialize codegen and IR passes used by llc so that the -print-after,
 304   // -print-before, and -stop-after options work.
 305   PassRegistry *Registry = PassRegistry::getPassRegistry();
 306   initializeCore(*Registry);
 307   initializeCodeGen(*Registry);
 308   initializeLoopStrengthReducePass(*Registry);
 309   initializeLowerIntrinsicsPass(*Registry);
 310   initializeEntryExitInstrumenterPass(*Registry);
 311   initializePostInlineEntryExitInstrumenterPass(*Registry);
 312   initializeUnreachableBlockElimLegacyPassPass(*Registry);
 313   initializeConstantHoistingLegacyPassPass(*Registry);
 314   initializeScalarOpts(*Registry);
 315   initializeVectorization(*Registry);
 316   initializeScalarizeMaskedMemIntrinPass(*Registry);
 317   initializeExpandReductionsPass(*Registry);
 318   initializeHardwareLoopsPass(*Registry);
 319
 320   // Initialize debugging passes.
 321   initializeScavengerTestPass(*Registry);
 322
 323   // Register the target printer for --version.
 324   cl::AddExtraVersionPrinter(TargetRegistry::printRegisteredTargetsForVersion);
 325
 326   cl::ParseCommandLineOptions(argc, argv, "llvm system compiler\n");
 327
 328   Context.setDiscardValueNames(DiscardValueNames);
 329
 330   // Set a diagnostic handler that doesn't exit on the first error
 331   bool HasError = false;
 332   Context.setDiagnosticHandler(
 333       std::make_unique<LLCDiagnosticHandler>(&HasError));
 334   Context.setInlineAsmDiagnosticHandler(InlineAsmDiagHandler, &HasError);
 335
 336   Expected<std::unique_ptr<ToolOutputFile>> RemarksFileOrErr =
 337       setupOptimizationRemarks(Context, RemarksFilename, RemarksPasses,
 338                                RemarksFormat, RemarksWithHotness,
 339                                RemarksHotnessThreshold);
 340   if (Error E = RemarksFileOrErr.takeError()) {
 341     WithColor::error(errs(), argv[0]) << toString(std::move(E)) << '\n';
 342     return 1;
 343   }
 344   std::unique_ptr<ToolOutputFile> RemarksFile = std::move(*RemarksFileOrErr);
 345
 346   if (InputLanguage != "" && InputLanguage != "ir" &&
 347       InputLanguage != "mir") {
 348     WithColor::error(errs(), argv[0])
 349         << "input language must be '', 'IR' or 'MIR'\n";
 350     return 1;
 351   }
 352
 353   // Compile the module TimeCompilations times to give better compile time
 354   // metrics.
 355   for (unsigned I = TimeCompilations; I; --I)
 356     if (int RetVal = compileModule(argv, Context))
 357       return RetVal;
 358
 359   if (RemarksFile)
 360     RemarksFile->keep();
 361   return 0;
 362 }
 363
 364 static bool addPass(PassManagerBase &PM, const char *argv0,
 365                     StringRef PassName, TargetPassConfig &TPC) {
 366   if (PassName == "none")
 367     return false;
 368
 369   const PassRegistry *PR = PassRegistry::getPassRegistry();
 370   const PassInfo *PI = PR->getPassInfo(PassName);
 371   if (!PI) {
 372     WithColor::error(errs(), argv0)
 373         << "run-pass " << PassName << " is not registered.\n";
 374     return true;
 375   }
 376
 377   Pass *P;
 378   if (PI->getNormalCtor())
 379     P = PI->getNormalCtor()();
 380   else {
 381     WithColor::error(errs(), argv0)
 382         << "cannot create pass: " << PI->getPassName() << "\n";
 383     return true;
 384   }
 385   std::string Banner = std::string("After ") + std::string(P->getPassName());
 386   PM.add(P);
 387   TPC.printAndVerify(Banner);
 388
 389   return false;
 390 }
 391
 392 static int compileModule(char **argv, LLVMContext &Context) {
 393   // Load the module to be compiled...
 394   SMDiagnostic Err;
 395   std::unique_ptr<Module> M;
 396   std::unique_ptr<MIRParser> MIR;
 397   Triple TheTriple;
 398   std::string CPUStr = getCPUStr(), FeaturesStr = getFeaturesStr();
 399
 400   // Set attributes on functions as loaded from MIR from command line arguments.
 401   auto setMIRFunctionAttributes = [&CPUStr, &FeaturesStr](Function &F) {
 402     setFunctionAttributes(CPUStr, FeaturesStr, F);
 403   };
 404
 405   bool SkipModule = MCPU == "help" ||
 406                     (!MAttrs.empty() && MAttrs.front() == "help");
 407
 408   // If user just wants to list available options, skip module loading
 409   if (!SkipModule) {
 410     if (InputLanguage == "mir" ||
 411         (InputLanguage == "" && StringRef(InputFilename).endswith(".mir"))) {
 412       MIR = createMIRParserFromFile(InputFilename, Err, Context,
 413                                     setMIRFunctionAttributes);
 414       if (MIR)
 415         M = MIR->parseIRModule();
 416     } else
 417       M = parseIRFile(InputFilename, Err, Context, false);
 418     if (!M) {
 419       Err.print(argv[0], WithColor::error(errs(), argv[0]));
 420       return 1;
 421     }
 422
 423     // If we are supposed to override the target triple, do so now.
 424     if (!TargetTriple.empty())
 425       M->setTargetTriple(Triple::normalize(TargetTriple));
 426     TheTriple = Triple(M->getTargetTriple());
 427   } else {
 428     TheTriple = Triple(Triple::normalize(TargetTriple));
 429   }
 430
 431   if (TheTriple.getTriple().empty())
 432     TheTriple.setTriple(sys::getDefaultTargetTriple());
 433
 434   // Get the target specific parser.
 435   std::string Error;
 436   const Target *TheTarget = TargetRegistry::lookupTarget(MArch, TheTriple,
 437                                                          Error);
 438   if (!TheTarget) {
 439     WithColor::error(errs(), argv[0]) << Error;
 440     return 1;
 441   }
 442
 443   CodeGenOpt::Level OLvl = CodeGenOpt::Default;
 444   switch (OptLevel) {
 445   default:
 446     WithColor::error(errs(), argv[0]) << "invalid optimization level.\n";
 447     return 1;
 448   case ' ': break;
 449   case '0': OLvl = CodeGenOpt::None; break;
 450   case '1': OLvl = CodeGenOpt::Less; break;
 451   case '2': OLvl = CodeGenOpt::Default; break;
 452   case '3': OLvl = CodeGenOpt::Aggressive; break;
 453   }
 454
 455   TargetOptions Options = InitTargetOptionsFromCodeGenFlags();
 456   Options.DisableIntegratedAS = NoIntegratedAssembler;
 457   Options.MCOptions.ShowMCEncoding = ShowMCEncoding;
 458   Options.MCOptions.MCUseDwarfDirectory = EnableDwarfDirectory;
 459   Options.MCOptions.AsmVerbose = AsmVerbose;
 460   Options.MCOptions.PreserveAsmComments = PreserveComments;
 461   Options.MCOptions.IASSearchPaths = IncludeDirs;
 462   Options.MCOptions.SplitDwarfFile = SplitDwarfFile;
 463
 464   // On AIX, setting the relocation model to anything other than PIC is considered
 465   // a user error.
 466   Optional<Reloc::Model> RM = getRelocModel();
 467   if (TheTriple.isOSAIX() && RM.hasValue() && *RM != Reloc::PIC_) {
 468     WithColor::error(errs(), argv[0])
 469         << "invalid relocation model, AIX only supports PIC.\n";
 470     return 1;
 471   }
 472
 473   std::unique_ptr<TargetMachine> Target(TheTarget->createTargetMachine(
 474       TheTriple.getTriple(), CPUStr, FeaturesStr, Options, RM,
 475       getCodeModel(), OLvl));
 476
 477   assert(Target && "Could not allocate target machine!");
 478
 479   // If we don't have a module then just exit now. We do this down
 480   // here since the CPU/Feature help is underneath the target machine
 481   // creation.
 482   if (SkipModule)
 483     return 0;
 484
 485   assert(M && "Should have exited if we didn't have a module!");
 486   if (FloatABIForCalls != FloatABI::Default)
 487     Options.FloatABIType = FloatABIForCalls;
 488
 489   // Figure out where we are going to send the output.
 490   std::unique_ptr<ToolOutputFile> Out =
 491       GetOutputStream(TheTarget->getName(), TheTriple.getOS(), argv[0]);
 492   if (!Out) return 1;
 493
 494   std::unique_ptr<ToolOutputFile> DwoOut;
 495   if (!SplitDwarfOutputFile.empty()) {
 496     std::error_code EC;
 497     DwoOut = std::make_unique<ToolOutputFile>(SplitDwarfOutputFile, EC,
 498                                                sys::fs::OF_None);
 499     if (EC) {
 500       WithColor::error(errs(), argv[0]) << EC.message() << '\n';
 501       return 1;
 502     }
 503   }
 504
 505   // Build up all of the passes that we want to do to the module.
 506   legacy::PassManager PM;
 507
 508   // Add an appropriate TargetLibraryInfo pass for the module's triple.
 509   TargetLibraryInfoImpl TLII(Triple(M->getTargetTriple()));
 510
 511   // The -disable-simplify-libcalls flag actually disables all builtin optzns.
 512   if (DisableSimplifyLibCalls)
 513     TLII.disableAllFunctions();
 514   PM.add(new TargetLibraryInfoWrapperPass(TLII));
 515
 516   // Add the target data from the target machine, if it exists, or the module.
 517   M->setDataLayout(Target->createDataLayout());
 518
 519   // This needs to be done after setting datalayout since it calls verifier
 520   // to check debug info whereas verifier relies on correct datalayout.
 521   UpgradeDebugInfo(*M);
 522
 523   // Verify module immediately to catch problems before doInitialization() is
 524   // called on any passes.
 525   if (!NoVerify && verifyModule(*M, &errs())) {
 526     std::string Prefix =
 527         (Twine(argv[0]) + Twine(": ") + Twine(InputFilename)).str();
 528     WithColor::error(errs(), Prefix) << "input module is broken!\n";
 529     return 1;
 530   }
 531
 532   // Override function attributes based on CPUStr, FeaturesStr, and command line
 533   // flags.
 534   setFunctionAttributes(CPUStr, FeaturesStr, *M);
 535
 536   if (RelaxAll.getNumOccurrences() > 0 &&
 537       FileType != CGFT_ObjectFile)
 538     WithColor::warning(errs(), argv[0])
 539         << ": warning: ignoring -mc-relax-all because filetype != obj";
 540
 541   {
 542     raw_pwrite_stream *OS = &Out->os();
 543
 544     // Manually do the buffering rather than using buffer_ostream,
 545     // so we can memcmp the contents in CompileTwice mode
 546     SmallVector<char, 0> Buffer;
 547     std::unique_ptr<raw_svector_ostream> BOS;
 548     if ((FileType != CGFT_AssemblyFile &&
 549          !Out->os().supportsSeeking()) ||
 550         CompileTwice) {
 551       BOS = std::make_unique<raw_svector_ostream>(Buffer);
 552       OS = BOS.get();
 553     }
 554
 555     const char *argv0 = argv[0];
 556     LLVMTargetMachine &LLVMTM = static_cast<LLVMTargetMachine &>(*Target);
 557     MachineModuleInfoWrapperPass *MMIWP =
 558         new MachineModuleInfoWrapperPass(&LLVMTM);
 559
 560     // Construct a custom pass pipeline that starts after instruction
 561     // selection.
 562     if (!RunPassNames->empty()) {
 563       if (!MIR) {
 564         WithColor::warning(errs(), argv[0])
 565             << "run-pass is for .mir file only.\n";
 566         return 1;
 567       }
 568       TargetPassConfig &TPC = *LLVMTM.createPassConfig(PM);
 569       if (TPC.hasLimitedCodeGenPipeline()) {
 570         WithColor::warning(errs(), argv[0])
 571             << "run-pass cannot be used with "
 572             << TPC.getLimitedCodeGenPipelineReason(" and ") << ".\n";
 573         return 1;
 574       }
 575
 576       TPC.setDisableVerify(NoVerify);
 577       PM.add(&TPC);
 578       PM.add(MMIWP);
 579       TPC.printAndVerify("");
 580       for (const std::string &RunPassName : *RunPassNames) {
 581         if (addPass(PM, argv0, RunPassName, TPC))
 582           return 1;
 583       }
 584       TPC.setInitialized();
 585       PM.add(createPrintMIRPass(*OS));
 586       PM.add(createFreeMachineFunctionPass());
 587     } else if (Target->addPassesToEmitFile(PM, *OS,
 588                                            DwoOut ? &DwoOut->os() : nullptr,
 589                                            FileType, NoVerify, MMIWP)) {
 590       WithColor::warning(errs(), argv[0])
 591           << "target does not support generation of this"
 592           << " file type!\n";
 593       return 1;
 594     }
 595
 596     if (MIR) {
 597       assert(MMIWP && "Forgot to create MMIWP?");
 598       if (MIR->parseMachineFunctions(*M, MMIWP->getMMI()))
 599         return 1;
 600     }
 601
 602     // Before executing passes, print the final values of the LLVM options.
 603     cl::PrintOptionValues();
 604
 605     // If requested, run the pass manager over the same module again,
 606     // to catch any bugs due to persistent state in the passes. Note that
 607     // opt has the same functionality, so it may be worth abstracting this out
 608     // in the future.
 609     SmallVector<char, 0> CompileTwiceBuffer;
 610     if (CompileTwice) {
 611       std::unique_ptr<Module> M2(llvm::CloneModule(*M));
 612       PM.run(*M2);
 613       CompileTwiceBuffer = Buffer;
 614       Buffer.clear();
 615     }
 616
 617     PM.run(*M);
 618
 619     auto HasError =
 620         ((const LLCDiagnosticHandler *)(Context.getDiagHandlerPtr()))->HasError;
 621     if (*HasError)
 622       return 1;
 623
 624     // Compare the two outputs and make sure they're the same
 625     if (CompileTwice) {
 626       if (Buffer.size() != CompileTwiceBuffer.size() ||
 627           (memcmp(Buffer.data(), CompileTwiceBuffer.data(), Buffer.size()) !=
 628            0)) {
 629         errs()
 630             << "Running the pass manager twice changed the output.\n"
 631                "Writing the result of the second run to the specified output\n"
 632                "To generate the one-run comparison binary, just run without\n"
 633                "the compile-twice option\n";
 634         Out->os() << Buffer;
 635         Out->keep();
 636         return 1;
 637       }
 638     }
 639
 640     if (BOS) {
 641       Out->os() << Buffer;
 642     }
 643   }
 644
 645   // Declare success.
 646   Out->keep();
 647   if (DwoOut)
 648     DwoOut->keep();
 649
 650   return 0;
 651 }