contrib/llvm/tools/clang/lib/CodeGen/BackendUtil.cpp

   1 //===--- BackendUtil.cpp - LLVM Backend Utilities -------------------------===//
   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 #include "clang/CodeGen/BackendUtil.h"
  11 #include "clang/Basic/Diagnostic.h"
  12 #include "clang/Basic/LangOptions.h"
  13 #include "clang/Basic/TargetOptions.h"
  14 #include "clang/Frontend/CodeGenOptions.h"
  15 #include "clang/Frontend/FrontendDiagnostic.h"
  16 #include "clang/Frontend/Utils.h"
  17 #include "llvm/ADT/StringSwitch.h"
  18 #include "llvm/Bitcode/BitcodeWriterPass.h"
  19 #include "llvm/CodeGen/RegAllocRegistry.h"
  20 #include "llvm/CodeGen/SchedulerRegistry.h"
  21 #include "llvm/IR/DataLayout.h"
  22 #include "llvm/IR/IRPrintingPasses.h"
  23 #include "llvm/IR/Module.h"
  24 #include "llvm/IR/Verifier.h"
  25 #include "llvm/MC/SubtargetFeature.h"
  26 #include "llvm/PassManager.h"
  27 #include "llvm/Support/CommandLine.h"
  28 #include "llvm/Support/FormattedStream.h"
  29 #include "llvm/Support/PrettyStackTrace.h"
  30 #include "llvm/Support/TargetRegistry.h"
  31 #include "llvm/Support/Timer.h"
  32 #include "llvm/Support/raw_ostream.h"
  33 #include "llvm/Target/TargetLibraryInfo.h"
  34 #include "llvm/Target/TargetMachine.h"
  35 #include "llvm/Target/TargetOptions.h"
  36 #include "llvm/Transforms/IPO.h"
  37 #include "llvm/Transforms/IPO/PassManagerBuilder.h"
  38 #include "llvm/Transforms/Instrumentation.h"
  39 #include "llvm/Transforms/ObjCARC.h"
  40 #include "llvm/Transforms/Scalar.h"
  41 #include <memory>
  42 using namespace clang;
  43 using namespace llvm;
  44
  45 namespace {
  46
  47 class EmitAssemblyHelper {
  48   DiagnosticsEngine &Diags;
  49   const CodeGenOptions &CodeGenOpts;
  50   const clang::TargetOptions &TargetOpts;
  51   const LangOptions &LangOpts;
  52   Module *TheModule;
  53
  54   Timer CodeGenerationTime;
  55
  56   mutable PassManager *CodeGenPasses;
  57   mutable PassManager *PerModulePasses;
  58   mutable FunctionPassManager *PerFunctionPasses;
  59
  60 private:
  61   PassManager *getCodeGenPasses() const {
  62     if (!CodeGenPasses) {
  63       CodeGenPasses = new PassManager();
  64       CodeGenPasses->add(new DataLayoutPass(TheModule));
  65       if (TM)
  66         TM->addAnalysisPasses(*CodeGenPasses);
  67     }
  68     return CodeGenPasses;
  69   }
  70
  71   PassManager *getPerModulePasses() const {
  72     if (!PerModulePasses) {
  73       PerModulePasses = new PassManager();
  74       PerModulePasses->add(new DataLayoutPass(TheModule));
  75       if (TM)
  76         TM->addAnalysisPasses(*PerModulePasses);
  77     }
  78     return PerModulePasses;
  79   }
  80
  81   FunctionPassManager *getPerFunctionPasses() const {
  82     if (!PerFunctionPasses) {
  83       PerFunctionPasses = new FunctionPassManager(TheModule);
  84       PerFunctionPasses->add(new DataLayoutPass(TheModule));
  85       if (TM)
  86         TM->addAnalysisPasses(*PerFunctionPasses);
  87     }
  88     return PerFunctionPasses;
  89   }
  90
  91   void CreatePasses();
  92
  93   /// CreateTargetMachine - Generates the TargetMachine.
  94   /// Returns Null if it is unable to create the target machine.
  95   /// Some of our clang tests specify triples which are not built
  96   /// into clang. This is okay because these tests check the generated
  97   /// IR, and they require DataLayout which depends on the triple.
  98   /// In this case, we allow this method to fail and not report an error.
  99   /// When MustCreateTM is used, we print an error if we are unable to load
 100   /// the requested target.
 101   TargetMachine *CreateTargetMachine(bool MustCreateTM);
 102
 103   /// AddEmitPasses - Add passes necessary to emit assembly or LLVM IR.
 104   ///
 105   /// \return True on success.
 106   bool AddEmitPasses(BackendAction Action, formatted_raw_ostream &OS);
 107
 108 public:
 109   EmitAssemblyHelper(DiagnosticsEngine &_Diags,
 110                      const CodeGenOptions &CGOpts,
 111                      const clang::TargetOptions &TOpts,
 112                      const LangOptions &LOpts,
 113                      Module *M)
 114     : Diags(_Diags), CodeGenOpts(CGOpts), TargetOpts(TOpts), LangOpts(LOpts),
 115       TheModule(M), CodeGenerationTime("Code Generation Time"),
 116       CodeGenPasses(nullptr), PerModulePasses(nullptr),
 117       PerFunctionPasses(nullptr) {}
 118
 119   ~EmitAssemblyHelper() {
 120     delete CodeGenPasses;
 121     delete PerModulePasses;
 122     delete PerFunctionPasses;
 123     if (CodeGenOpts.DisableFree)
 124       BuryPointer(TM.release());
 125   }
 126
 127   std::unique_ptr<TargetMachine> TM;
 128
 129   void EmitAssembly(BackendAction Action, raw_ostream *OS);
 130 };
 131
 132 // We need this wrapper to access LangOpts and CGOpts from extension functions
 133 // that we add to the PassManagerBuilder.
 134 class PassManagerBuilderWrapper : public PassManagerBuilder {
 135 public:
 136   PassManagerBuilderWrapper(const CodeGenOptions &CGOpts,
 137                             const LangOptions &LangOpts)
 138       : PassManagerBuilder(), CGOpts(CGOpts), LangOpts(LangOpts) {}
 139   const CodeGenOptions &getCGOpts() const { return CGOpts; }
 140   const LangOptions &getLangOpts() const { return LangOpts; }
 141 private:
 142   const CodeGenOptions &CGOpts;
 143   const LangOptions &LangOpts;
 144 };
 145
 146 }
 147
 148 static void addObjCARCAPElimPass(const PassManagerBuilder &Builder, PassManagerBase &PM) {
 149   if (Builder.OptLevel > 0)
 150     PM.add(createObjCARCAPElimPass());
 151 }
 152
 153 static void addObjCARCExpandPass(const PassManagerBuilder &Builder, PassManagerBase &PM) {
 154   if (Builder.OptLevel > 0)
 155     PM.add(createObjCARCExpandPass());
 156 }
 157
 158 static void addObjCARCOptPass(const PassManagerBuilder &Builder, PassManagerBase &PM) {
 159   if (Builder.OptLevel > 0)
 160     PM.add(createObjCARCOptPass());
 161 }
 162
 163 static void addSampleProfileLoaderPass(const PassManagerBuilder &Builder,
 164                                        PassManagerBase &PM) {
 165   const PassManagerBuilderWrapper &BuilderWrapper =
 166       static_cast<const PassManagerBuilderWrapper &>(Builder);
 167   const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
 168   PM.add(createSampleProfileLoaderPass(CGOpts.SampleProfileFile));
 169 }
 170
 171 static void addAddDiscriminatorsPass(const PassManagerBuilder &Builder,
 172                                      PassManagerBase &PM) {
 173   PM.add(createAddDiscriminatorsPass());
 174 }
 175
 176 static void addBoundsCheckingPass(const PassManagerBuilder &Builder,
 177                                     PassManagerBase &PM) {
 178   PM.add(createBoundsCheckingPass());
 179 }
 180
 181 static void addAddressSanitizerPasses(const PassManagerBuilder &Builder,
 182                                       PassManagerBase &PM) {
 183   PM.add(createAddressSanitizerFunctionPass());
 184   PM.add(createAddressSanitizerModulePass());
 185 }
 186
 187 static void addMemorySanitizerPass(const PassManagerBuilder &Builder,
 188                                    PassManagerBase &PM) {
 189   const PassManagerBuilderWrapper &BuilderWrapper =
 190       static_cast<const PassManagerBuilderWrapper&>(Builder);
 191   const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
 192   PM.add(createMemorySanitizerPass(CGOpts.SanitizeMemoryTrackOrigins));
 193
 194   // MemorySanitizer inserts complex instrumentation that mostly follows
 195   // the logic of the original code, but operates on "shadow" values.
 196   // It can benefit from re-running some general purpose optimization passes.
 197   if (Builder.OptLevel > 0) {
 198     PM.add(createEarlyCSEPass());
 199     PM.add(createReassociatePass());
 200     PM.add(createLICMPass());
 201     PM.add(createGVNPass());
 202     PM.add(createInstructionCombiningPass());
 203     PM.add(createDeadStoreEliminationPass());
 204   }
 205 }
 206
 207 static void addThreadSanitizerPass(const PassManagerBuilder &Builder,
 208                                    PassManagerBase &PM) {
 209   PM.add(createThreadSanitizerPass());
 210 }
 211
 212 static void addDataFlowSanitizerPass(const PassManagerBuilder &Builder,
 213                                      PassManagerBase &PM) {
 214   const PassManagerBuilderWrapper &BuilderWrapper =
 215       static_cast<const PassManagerBuilderWrapper&>(Builder);
 216   const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
 217   PM.add(createDataFlowSanitizerPass(CGOpts.SanitizerBlacklistFile));
 218 }
 219
 220 void EmitAssemblyHelper::CreatePasses() {
 221   unsigned OptLevel = CodeGenOpts.OptimizationLevel;
 222   CodeGenOptions::InliningMethod Inlining = CodeGenOpts.getInlining();
 223
 224   // Handle disabling of LLVM optimization, where we want to preserve the
 225   // internal module before any optimization.
 226   if (CodeGenOpts.DisableLLVMOpts) {
 227     OptLevel = 0;
 228     Inlining = CodeGenOpts.NoInlining;
 229   }
 230
 231   PassManagerBuilderWrapper PMBuilder(CodeGenOpts, LangOpts);
 232   PMBuilder.OptLevel = OptLevel;
 233   PMBuilder.SizeLevel = CodeGenOpts.OptimizeSize;
 234   PMBuilder.BBVectorize = CodeGenOpts.VectorizeBB;
 235   PMBuilder.SLPVectorize = CodeGenOpts.VectorizeSLP;
 236   PMBuilder.LoopVectorize = CodeGenOpts.VectorizeLoop;
 237
 238   PMBuilder.DisableTailCalls = CodeGenOpts.DisableTailCalls;
 239   PMBuilder.DisableUnitAtATime = !CodeGenOpts.UnitAtATime;
 240   PMBuilder.DisableUnrollLoops = !CodeGenOpts.UnrollLoops;
 241   PMBuilder.RerollLoops = CodeGenOpts.RerollLoops;
 242
 243   PMBuilder.addExtension(PassManagerBuilder::EP_EarlyAsPossible,
 244                          addAddDiscriminatorsPass);
 245
 246   if (!CodeGenOpts.SampleProfileFile.empty())
 247     PMBuilder.addExtension(PassManagerBuilder::EP_EarlyAsPossible,
 248                            addSampleProfileLoaderPass);
 249
 250   // In ObjC ARC mode, add the main ARC optimization passes.
 251   if (LangOpts.ObjCAutoRefCount) {
 252     PMBuilder.addExtension(PassManagerBuilder::EP_EarlyAsPossible,
 253                            addObjCARCExpandPass);
 254     PMBuilder.addExtension(PassManagerBuilder::EP_ModuleOptimizerEarly,
 255                            addObjCARCAPElimPass);
 256     PMBuilder.addExtension(PassManagerBuilder::EP_ScalarOptimizerLate,
 257                            addObjCARCOptPass);
 258   }
 259
 260   if (LangOpts.Sanitize.LocalBounds) {
 261     PMBuilder.addExtension(PassManagerBuilder::EP_ScalarOptimizerLate,
 262                            addBoundsCheckingPass);
 263     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
 264                            addBoundsCheckingPass);
 265   }
 266
 267   if (LangOpts.Sanitize.Address) {
 268     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
 269                            addAddressSanitizerPasses);
 270     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
 271                            addAddressSanitizerPasses);
 272   }
 273
 274   if (LangOpts.Sanitize.Memory) {
 275     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
 276                            addMemorySanitizerPass);
 277     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
 278                            addMemorySanitizerPass);
 279   }
 280
 281   if (LangOpts.Sanitize.Thread) {
 282     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
 283                            addThreadSanitizerPass);
 284     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
 285                            addThreadSanitizerPass);
 286   }
 287
 288   if (LangOpts.Sanitize.DataFlow) {
 289     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
 290                            addDataFlowSanitizerPass);
 291     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
 292                            addDataFlowSanitizerPass);
 293   }
 294
 295   // Figure out TargetLibraryInfo.
 296   Triple TargetTriple(TheModule->getTargetTriple());
 297   PMBuilder.LibraryInfo = new TargetLibraryInfo(TargetTriple);
 298   if (!CodeGenOpts.SimplifyLibCalls)
 299     PMBuilder.LibraryInfo->disableAllFunctions();
 300
 301   switch (Inlining) {
 302   case CodeGenOptions::NoInlining: break;
 303   case CodeGenOptions::NormalInlining: {
 304     PMBuilder.Inliner =
 305         createFunctionInliningPass(OptLevel, CodeGenOpts.OptimizeSize);
 306     break;
 307   }
 308   case CodeGenOptions::OnlyAlwaysInlining:
 309     // Respect always_inline.
 310     if (OptLevel == 0)
 311       // Do not insert lifetime intrinsics at -O0.
 312       PMBuilder.Inliner = createAlwaysInlinerPass(false);
 313     else
 314       PMBuilder.Inliner = createAlwaysInlinerPass();
 315     break;
 316   }
 317
 318   // Set up the per-function pass manager.
 319   FunctionPassManager *FPM = getPerFunctionPasses();
 320   if (CodeGenOpts.VerifyModule)
 321     FPM->add(createVerifierPass());
 322   PMBuilder.populateFunctionPassManager(*FPM);
 323
 324   // Set up the per-module pass manager.
 325   PassManager *MPM = getPerModulePasses();
 326   if (CodeGenOpts.VerifyModule)
 327     MPM->add(createDebugInfoVerifierPass());
 328
 329   if (!CodeGenOpts.DisableGCov &&
 330       (CodeGenOpts.EmitGcovArcs || CodeGenOpts.EmitGcovNotes)) {
 331     // Not using 'GCOVOptions::getDefault' allows us to avoid exiting if
 332     // LLVM's -default-gcov-version flag is set to something invalid.
 333     GCOVOptions Options;
 334     Options.EmitNotes = CodeGenOpts.EmitGcovNotes;
 335     Options.EmitData = CodeGenOpts.EmitGcovArcs;
 336     memcpy(Options.Version, CodeGenOpts.CoverageVersion, 4);
 337     Options.UseCfgChecksum = CodeGenOpts.CoverageExtraChecksum;
 338     Options.NoRedZone = CodeGenOpts.DisableRedZone;
 339     Options.FunctionNamesInData =
 340         !CodeGenOpts.CoverageNoFunctionNamesInData;
 341     MPM->add(createGCOVProfilerPass(Options));
 342     if (CodeGenOpts.getDebugInfo() == CodeGenOptions::NoDebugInfo)
 343       MPM->add(createStripSymbolsPass(true));
 344   }
 345
 346   PMBuilder.populateModulePassManager(*MPM);
 347 }
 348
 349 TargetMachine *EmitAssemblyHelper::CreateTargetMachine(bool MustCreateTM) {
 350   // Create the TargetMachine for generating code.
 351   std::string Error;
 352   std::string Triple = TheModule->getTargetTriple();
 353   const llvm::Target *TheTarget = TargetRegistry::lookupTarget(Triple, Error);
 354   if (!TheTarget) {
 355     if (MustCreateTM)
 356       Diags.Report(diag::err_fe_unable_to_create_target) << Error;
 357     return nullptr;
 358   }
 359
 360   unsigned CodeModel =
 361     llvm::StringSwitch<unsigned>(CodeGenOpts.CodeModel)
 362       .Case("small", llvm::CodeModel::Small)
 363       .Case("kernel", llvm::CodeModel::Kernel)
 364       .Case("medium", llvm::CodeModel::Medium)
 365       .Case("large", llvm::CodeModel::Large)
 366       .Case("default", llvm::CodeModel::Default)
 367       .Default(~0u);
 368   assert(CodeModel != ~0u && "invalid code model!");
 369   llvm::CodeModel::Model CM = static_cast<llvm::CodeModel::Model>(CodeModel);
 370
 371   SmallVector<const char *, 16> BackendArgs;
 372   BackendArgs.push_back("clang"); // Fake program name.
 373   if (!CodeGenOpts.DebugPass.empty()) {
 374     BackendArgs.push_back("-debug-pass");
 375     BackendArgs.push_back(CodeGenOpts.DebugPass.c_str());
 376   }
 377   if (!CodeGenOpts.LimitFloatPrecision.empty()) {
 378     BackendArgs.push_back("-limit-float-precision");
 379     BackendArgs.push_back(CodeGenOpts.LimitFloatPrecision.c_str());
 380   }
 381   if (llvm::TimePassesIsEnabled)
 382     BackendArgs.push_back("-time-passes");
 383   for (unsigned i = 0, e = CodeGenOpts.BackendOptions.size(); i != e; ++i)
 384     BackendArgs.push_back(CodeGenOpts.BackendOptions[i].c_str());
 385   if (CodeGenOpts.NoGlobalMerge)
 386     BackendArgs.push_back("-enable-global-merge=false");
 387   BackendArgs.push_back(nullptr);
 388   llvm::cl::ParseCommandLineOptions(BackendArgs.size() - 1,
 389                                     BackendArgs.data());
 390
 391   std::string FeaturesStr;
 392   if (TargetOpts.Features.size()) {
 393     SubtargetFeatures Features;
 394     for (std::vector<std::string>::const_iterator
 395            it = TargetOpts.Features.begin(),
 396            ie = TargetOpts.Features.end(); it != ie; ++it)
 397       Features.AddFeature(*it);
 398     FeaturesStr = Features.getString();
 399   }
 400
 401   llvm::Reloc::Model RM = llvm::Reloc::Default;
 402   if (CodeGenOpts.RelocationModel == "static") {
 403     RM = llvm::Reloc::Static;
 404   } else if (CodeGenOpts.RelocationModel == "pic") {
 405     RM = llvm::Reloc::PIC_;
 406   } else {
 407     assert(CodeGenOpts.RelocationModel == "dynamic-no-pic" &&
 408            "Invalid PIC model!");
 409     RM = llvm::Reloc::DynamicNoPIC;
 410   }
 411
 412   CodeGenOpt::Level OptLevel = CodeGenOpt::Default;
 413   switch (CodeGenOpts.OptimizationLevel) {
 414   default: break;
 415   case 0: OptLevel = CodeGenOpt::None; break;
 416   case 3: OptLevel = CodeGenOpt::Aggressive; break;
 417   }
 418
 419   llvm::TargetOptions Options;
 420
 421   if (CodeGenOpts.DisableIntegratedAS)
 422     Options.DisableIntegratedAS = true;
 423
 424   if (CodeGenOpts.CompressDebugSections)
 425     Options.CompressDebugSections = true;
 426
 427   // Set frame pointer elimination mode.
 428   if (!CodeGenOpts.DisableFPElim) {
 429     Options.NoFramePointerElim = false;
 430   } else if (CodeGenOpts.OmitLeafFramePointer) {
 431     Options.NoFramePointerElim = false;
 432   } else {
 433     Options.NoFramePointerElim = true;
 434   }
 435
 436   if (CodeGenOpts.UseInitArray)
 437     Options.UseInitArray = true;
 438
 439   // Set float ABI type.
 440   if (CodeGenOpts.FloatABI == "soft" || CodeGenOpts.FloatABI == "softfp")
 441     Options.FloatABIType = llvm::FloatABI::Soft;
 442   else if (CodeGenOpts.FloatABI == "hard")
 443     Options.FloatABIType = llvm::FloatABI::Hard;
 444   else {
 445     assert(CodeGenOpts.FloatABI.empty() && "Invalid float abi!");
 446     Options.FloatABIType = llvm::FloatABI::Default;
 447   }
 448
 449   // Set FP fusion mode.
 450   switch (CodeGenOpts.getFPContractMode()) {
 451   case CodeGenOptions::FPC_Off:
 452     Options.AllowFPOpFusion = llvm::FPOpFusion::Strict;
 453     break;
 454   case CodeGenOptions::FPC_On:
 455     Options.AllowFPOpFusion = llvm::FPOpFusion::Standard;
 456     break;
 457   case CodeGenOptions::FPC_Fast:
 458     Options.AllowFPOpFusion = llvm::FPOpFusion::Fast;
 459     break;
 460   }
 461
 462   Options.LessPreciseFPMADOption = CodeGenOpts.LessPreciseFPMAD;
 463   Options.NoInfsFPMath = CodeGenOpts.NoInfsFPMath;
 464   Options.NoNaNsFPMath = CodeGenOpts.NoNaNsFPMath;
 465   Options.NoZerosInBSS = CodeGenOpts.NoZeroInitializedInBSS;
 466   Options.UnsafeFPMath = CodeGenOpts.UnsafeFPMath;
 467   Options.UseSoftFloat = CodeGenOpts.SoftFloat;
 468   Options.StackAlignmentOverride = CodeGenOpts.StackAlignment;
 469   Options.DisableTailCalls = CodeGenOpts.DisableTailCalls;
 470   Options.TrapFuncName = CodeGenOpts.TrapFuncName;
 471   Options.PositionIndependentExecutable = LangOpts.PIELevel != 0;
 472   Options.FunctionSections = CodeGenOpts.FunctionSections;
 473   Options.DataSections = CodeGenOpts.DataSections;
 474
 475   Options.MCOptions.MCRelaxAll = CodeGenOpts.RelaxAll;
 476   Options.MCOptions.MCSaveTempLabels = CodeGenOpts.SaveTempLabels;
 477   Options.MCOptions.MCUseDwarfDirectory = !CodeGenOpts.NoDwarfDirectoryAsm;
 478   Options.MCOptions.MCNoExecStack = CodeGenOpts.NoExecStack;
 479   Options.MCOptions.AsmVerbose = CodeGenOpts.AsmVerbose;
 480
 481   TargetMachine *TM = TheTarget->createTargetMachine(Triple, TargetOpts.CPU,
 482                                                      FeaturesStr, Options,
 483                                                      RM, CM, OptLevel);
 484
 485   return TM;
 486 }
 487
 488 bool EmitAssemblyHelper::AddEmitPasses(BackendAction Action,
 489                                        formatted_raw_ostream &OS) {
 490
 491   // Create the code generator passes.
 492   PassManager *PM = getCodeGenPasses();
 493
 494   // Add LibraryInfo.
 495   llvm::Triple TargetTriple(TheModule->getTargetTriple());
 496   TargetLibraryInfo *TLI = new TargetLibraryInfo(TargetTriple);
 497   if (!CodeGenOpts.SimplifyLibCalls)
 498     TLI->disableAllFunctions();
 499   PM->add(TLI);
 500
 501   // Add Target specific analysis passes.
 502   TM->addAnalysisPasses(*PM);
 503
 504   // Normal mode, emit a .s or .o file by running the code generator. Note,
 505   // this also adds codegenerator level optimization passes.
 506   TargetMachine::CodeGenFileType CGFT = TargetMachine::CGFT_AssemblyFile;
 507   if (Action == Backend_EmitObj)
 508     CGFT = TargetMachine::CGFT_ObjectFile;
 509   else if (Action == Backend_EmitMCNull)
 510     CGFT = TargetMachine::CGFT_Null;
 511   else
 512     assert(Action == Backend_EmitAssembly && "Invalid action!");
 513
 514   // Add ObjC ARC final-cleanup optimizations. This is done as part of the
 515   // "codegen" passes so that it isn't run multiple times when there is
 516   // inlining happening.
 517   if (LangOpts.ObjCAutoRefCount &&
 518       CodeGenOpts.OptimizationLevel > 0)
 519     PM->add(createObjCARCContractPass());
 520
 521   if (TM->addPassesToEmitFile(*PM, OS, CGFT,
 522                               /*DisableVerify=*/!CodeGenOpts.VerifyModule)) {
 523     Diags.Report(diag::err_fe_unable_to_interface_with_target);
 524     return false;
 525   }
 526
 527   return true;
 528 }
 529
 530 void EmitAssemblyHelper::EmitAssembly(BackendAction Action, raw_ostream *OS) {
 531   TimeRegion Region(llvm::TimePassesIsEnabled ? &CodeGenerationTime : nullptr);
 532   llvm::formatted_raw_ostream FormattedOS;
 533
 534   bool UsesCodeGen = (Action != Backend_EmitNothing &&
 535                       Action != Backend_EmitBC &&
 536                       Action != Backend_EmitLL);
 537   if (!TM)
 538     TM.reset(CreateTargetMachine(UsesCodeGen));
 539
 540   if (UsesCodeGen && !TM) return;
 541   CreatePasses();
 542
 543   switch (Action) {
 544   case Backend_EmitNothing:
 545     break;
 546
 547   case Backend_EmitBC:
 548     getPerModulePasses()->add(createBitcodeWriterPass(*OS));
 549     break;
 550
 551   case Backend_EmitLL:
 552     FormattedOS.setStream(*OS, formatted_raw_ostream::PRESERVE_STREAM);
 553     getPerModulePasses()->add(createPrintModulePass(FormattedOS));
 554     break;
 555
 556   default:
 557     FormattedOS.setStream(*OS, formatted_raw_ostream::PRESERVE_STREAM);
 558     if (!AddEmitPasses(Action, FormattedOS))
 559       return;
 560   }
 561
 562   // Before executing passes, print the final values of the LLVM options.
 563   cl::PrintOptionValues();
 564
 565   // Run passes. For now we do all passes at once, but eventually we
 566   // would like to have the option of streaming code generation.
 567
 568   if (PerFunctionPasses) {
 569     PrettyStackTraceString CrashInfo("Per-function optimization");
 570
 571     PerFunctionPasses->doInitialization();
 572     for (Module::iterator I = TheModule->begin(),
 573            E = TheModule->end(); I != E; ++I)
 574       if (!I->isDeclaration())
 575         PerFunctionPasses->run(*I);
 576     PerFunctionPasses->doFinalization();
 577   }
 578
 579   if (PerModulePasses) {
 580     PrettyStackTraceString CrashInfo("Per-module optimization passes");
 581     PerModulePasses->run(*TheModule);
 582   }
 583
 584   if (CodeGenPasses) {
 585     PrettyStackTraceString CrashInfo("Code generation");
 586     CodeGenPasses->run(*TheModule);
 587   }
 588 }
 589
 590 void clang::EmitBackendOutput(DiagnosticsEngine &Diags,
 591                               const CodeGenOptions &CGOpts,
 592                               const clang::TargetOptions &TOpts,
 593                               const LangOptions &LOpts, StringRef TDesc,
 594                               Module *M, BackendAction Action,
 595                               raw_ostream *OS) {
 596   EmitAssemblyHelper AsmHelper(Diags, CGOpts, TOpts, LOpts, M);
 597
 598   AsmHelper.EmitAssembly(Action, OS);
 599
 600   // If an optional clang TargetInfo description string was passed in, use it to
 601   // verify the LLVM TargetMachine's DataLayout.
 602   if (AsmHelper.TM && !TDesc.empty()) {
 603     std::string DLDesc =
 604         AsmHelper.TM->getDataLayout()->getStringRepresentation();
 605     if (DLDesc != TDesc) {
 606       unsigned DiagID = Diags.getCustomDiagID(
 607           DiagnosticsEngine::Error, "backend data layout '%0' does not match "
 608                                     "expected target description '%1'");
 609       Diags.Report(DiagID) << DLDesc << TDesc;
 610     }
 611   }
 612 }