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 "clang/Lex/HeaderSearchOptions.h"
  18 #include "llvm/ADT/SmallSet.h"
  19 #include "llvm/ADT/StringExtras.h"
  20 #include "llvm/ADT/StringSwitch.h"
  21 #include "llvm/ADT/Triple.h"
  22 #include "llvm/Analysis/TargetLibraryInfo.h"
  23 #include "llvm/Analysis/TargetTransformInfo.h"
  24 #include "llvm/Bitcode/BitcodeReader.h"
  25 #include "llvm/Bitcode/BitcodeWriter.h"
  26 #include "llvm/Bitcode/BitcodeWriterPass.h"
  27 #include "llvm/CodeGen/RegAllocRegistry.h"
  28 #include "llvm/CodeGen/SchedulerRegistry.h"
  29 #include "llvm/IR/DataLayout.h"
  30 #include "llvm/IR/IRPrintingPasses.h"
  31 #include "llvm/IR/LegacyPassManager.h"
  32 #include "llvm/IR/Module.h"
  33 #include "llvm/IR/ModuleSummaryIndex.h"
  34 #include "llvm/IR/Verifier.h"
  35 #include "llvm/LTO/LTOBackend.h"
  36 #include "llvm/MC/MCAsmInfo.h"
  37 #include "llvm/MC/SubtargetFeature.h"
  38 #include "llvm/Passes/PassBuilder.h"
  39 #include "llvm/Support/CommandLine.h"
  40 #include "llvm/Support/MemoryBuffer.h"
  41 #include "llvm/Support/PrettyStackTrace.h"
  42 #include "llvm/Support/TargetRegistry.h"
  43 #include "llvm/Support/Timer.h"
  44 #include "llvm/Support/raw_ostream.h"
  45 #include "llvm/Target/TargetMachine.h"
  46 #include "llvm/Target/TargetOptions.h"
  47 #include "llvm/CodeGen/TargetSubtargetInfo.h"
  48 #include "llvm/Transforms/Coroutines.h"
  49 #include "llvm/Transforms/IPO.h"
  50 #include "llvm/Transforms/IPO/AlwaysInliner.h"
  51 #include "llvm/Transforms/IPO/PassManagerBuilder.h"
  52 #include "llvm/Transforms/IPO/ThinLTOBitcodeWriter.h"
  53 #include "llvm/Transforms/Instrumentation.h"
  54 #include "llvm/Transforms/Instrumentation/BoundsChecking.h"
  55 #include "llvm/Transforms/ObjCARC.h"
  56 #include "llvm/Transforms/Scalar.h"
  57 #include "llvm/Transforms/Scalar/GVN.h"
  58 #include "llvm/Transforms/Utils/NameAnonGlobals.h"
  59 #include "llvm/Transforms/Utils/SymbolRewriter.h"
  60 #include <memory>
  61 using namespace clang;
  62 using namespace llvm;
  63
  64 namespace {
  65
  66 // Default filename used for profile generation.
  67 static constexpr StringLiteral DefaultProfileGenName = "default_%m.profraw";
  68
  69 class EmitAssemblyHelper {
  70   DiagnosticsEngine &Diags;
  71   const HeaderSearchOptions &HSOpts;
  72   const CodeGenOptions &CodeGenOpts;
  73   const clang::TargetOptions &TargetOpts;
  74   const LangOptions &LangOpts;
  75   Module *TheModule;
  76
  77   Timer CodeGenerationTime;
  78
  79   std::unique_ptr<raw_pwrite_stream> OS;
  80
  81   TargetIRAnalysis getTargetIRAnalysis() const {
  82     if (TM)
  83       return TM->getTargetIRAnalysis();
  84
  85     return TargetIRAnalysis();
  86   }
  87
  88   void CreatePasses(legacy::PassManager &MPM, legacy::FunctionPassManager &FPM);
  89
  90   /// Generates the TargetMachine.
  91   /// Leaves TM unchanged if it is unable to create the target machine.
  92   /// Some of our clang tests specify triples which are not built
  93   /// into clang. This is okay because these tests check the generated
  94   /// IR, and they require DataLayout which depends on the triple.
  95   /// In this case, we allow this method to fail and not report an error.
  96   /// When MustCreateTM is used, we print an error if we are unable to load
  97   /// the requested target.
  98   void CreateTargetMachine(bool MustCreateTM);
  99
 100   /// Add passes necessary to emit assembly or LLVM IR.
 101   ///
 102   /// \return True on success.
 103   bool AddEmitPasses(legacy::PassManager &CodeGenPasses, BackendAction Action,
 104                      raw_pwrite_stream &OS);
 105
 106 public:
 107   EmitAssemblyHelper(DiagnosticsEngine &_Diags,
 108                      const HeaderSearchOptions &HeaderSearchOpts,
 109                      const CodeGenOptions &CGOpts,
 110                      const clang::TargetOptions &TOpts,
 111                      const LangOptions &LOpts, Module *M)
 112       : Diags(_Diags), HSOpts(HeaderSearchOpts), CodeGenOpts(CGOpts),
 113         TargetOpts(TOpts), LangOpts(LOpts), TheModule(M),
 114         CodeGenerationTime("codegen", "Code Generation Time") {}
 115
 116   ~EmitAssemblyHelper() {
 117     if (CodeGenOpts.DisableFree)
 118       BuryPointer(std::move(TM));
 119   }
 120
 121   std::unique_ptr<TargetMachine> TM;
 122
 123   void EmitAssembly(BackendAction Action,
 124                     std::unique_ptr<raw_pwrite_stream> OS);
 125
 126   void EmitAssemblyWithNewPassManager(BackendAction Action,
 127                                       std::unique_ptr<raw_pwrite_stream> OS);
 128 };
 129
 130 // We need this wrapper to access LangOpts and CGOpts from extension functions
 131 // that we add to the PassManagerBuilder.
 132 class PassManagerBuilderWrapper : public PassManagerBuilder {
 133 public:
 134   PassManagerBuilderWrapper(const Triple &TargetTriple,
 135                             const CodeGenOptions &CGOpts,
 136                             const LangOptions &LangOpts)
 137       : PassManagerBuilder(), TargetTriple(TargetTriple), CGOpts(CGOpts),
 138         LangOpts(LangOpts) {}
 139   const Triple &getTargetTriple() const { return TargetTriple; }
 140   const CodeGenOptions &getCGOpts() const { return CGOpts; }
 141   const LangOptions &getLangOpts() const { return LangOpts; }
 142
 143 private:
 144   const Triple &TargetTriple;
 145   const CodeGenOptions &CGOpts;
 146   const LangOptions &LangOpts;
 147 };
 148 }
 149
 150 static void addObjCARCAPElimPass(const PassManagerBuilder &Builder, PassManagerBase &PM) {
 151   if (Builder.OptLevel > 0)
 152     PM.add(createObjCARCAPElimPass());
 153 }
 154
 155 static void addObjCARCExpandPass(const PassManagerBuilder &Builder, PassManagerBase &PM) {
 156   if (Builder.OptLevel > 0)
 157     PM.add(createObjCARCExpandPass());
 158 }
 159
 160 static void addObjCARCOptPass(const PassManagerBuilder &Builder, PassManagerBase &PM) {
 161   if (Builder.OptLevel > 0)
 162     PM.add(createObjCARCOptPass());
 163 }
 164
 165 static void addAddDiscriminatorsPass(const PassManagerBuilder &Builder,
 166                                      legacy::PassManagerBase &PM) {
 167   PM.add(createAddDiscriminatorsPass());
 168 }
 169
 170 static void addBoundsCheckingPass(const PassManagerBuilder &Builder,
 171                                   legacy::PassManagerBase &PM) {
 172   PM.add(createBoundsCheckingLegacyPass());
 173 }
 174
 175 static void addSanitizerCoveragePass(const PassManagerBuilder &Builder,
 176                                      legacy::PassManagerBase &PM) {
 177   const PassManagerBuilderWrapper &BuilderWrapper =
 178       static_cast<const PassManagerBuilderWrapper&>(Builder);
 179   const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
 180   SanitizerCoverageOptions Opts;
 181   Opts.CoverageType =
 182       static_cast<SanitizerCoverageOptions::Type>(CGOpts.SanitizeCoverageType);
 183   Opts.IndirectCalls = CGOpts.SanitizeCoverageIndirectCalls;
 184   Opts.TraceBB = CGOpts.SanitizeCoverageTraceBB;
 185   Opts.TraceCmp = CGOpts.SanitizeCoverageTraceCmp;
 186   Opts.TraceDiv = CGOpts.SanitizeCoverageTraceDiv;
 187   Opts.TraceGep = CGOpts.SanitizeCoverageTraceGep;
 188   Opts.Use8bitCounters = CGOpts.SanitizeCoverage8bitCounters;
 189   Opts.TracePC = CGOpts.SanitizeCoverageTracePC;
 190   Opts.TracePCGuard = CGOpts.SanitizeCoverageTracePCGuard;
 191   Opts.NoPrune = CGOpts.SanitizeCoverageNoPrune;
 192   Opts.Inline8bitCounters = CGOpts.SanitizeCoverageInline8bitCounters;
 193   Opts.PCTable = CGOpts.SanitizeCoveragePCTable;
 194   Opts.StackDepth = CGOpts.SanitizeCoverageStackDepth;
 195   PM.add(createSanitizerCoverageModulePass(Opts));
 196 }
 197
 198 // Check if ASan should use GC-friendly instrumentation for globals.
 199 // First of all, there is no point if -fdata-sections is off (expect for MachO,
 200 // where this is not a factor). Also, on ELF this feature requires an assembler
 201 // extension that only works with -integrated-as at the moment.
 202 static bool asanUseGlobalsGC(const Triple &T, const CodeGenOptions &CGOpts) {
 203   if (!CGOpts.SanitizeAddressGlobalsDeadStripping)
 204     return false;
 205   switch (T.getObjectFormat()) {
 206   case Triple::MachO:
 207   case Triple::COFF:
 208     return true;
 209   case Triple::ELF:
 210     return CGOpts.DataSections && !CGOpts.DisableIntegratedAS;
 211   default:
 212     return false;
 213   }
 214 }
 215
 216 static void addAddressSanitizerPasses(const PassManagerBuilder &Builder,
 217                                       legacy::PassManagerBase &PM) {
 218   const PassManagerBuilderWrapper &BuilderWrapper =
 219       static_cast<const PassManagerBuilderWrapper&>(Builder);
 220   const Triple &T = BuilderWrapper.getTargetTriple();
 221   const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
 222   bool Recover = CGOpts.SanitizeRecover.has(SanitizerKind::Address);
 223   bool UseAfterScope = CGOpts.SanitizeAddressUseAfterScope;
 224   bool UseGlobalsGC = asanUseGlobalsGC(T, CGOpts);
 225   PM.add(createAddressSanitizerFunctionPass(/*CompileKernel*/ false, Recover,
 226                                             UseAfterScope));
 227   PM.add(createAddressSanitizerModulePass(/*CompileKernel*/ false, Recover,
 228                                           UseGlobalsGC));
 229 }
 230
 231 static void addKernelAddressSanitizerPasses(const PassManagerBuilder &Builder,
 232                                             legacy::PassManagerBase &PM) {
 233   PM.add(createAddressSanitizerFunctionPass(
 234       /*CompileKernel*/ true,
 235       /*Recover*/ true, /*UseAfterScope*/ false));
 236   PM.add(createAddressSanitizerModulePass(/*CompileKernel*/true,
 237                                           /*Recover*/true));
 238 }
 239
 240 static void addHWAddressSanitizerPasses(const PassManagerBuilder &Builder,
 241                                             legacy::PassManagerBase &PM) {
 242   PM.add(createHWAddressSanitizerPass());
 243 }
 244
 245 static void addMemorySanitizerPass(const PassManagerBuilder &Builder,
 246                                    legacy::PassManagerBase &PM) {
 247   const PassManagerBuilderWrapper &BuilderWrapper =
 248       static_cast<const PassManagerBuilderWrapper&>(Builder);
 249   const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
 250   int TrackOrigins = CGOpts.SanitizeMemoryTrackOrigins;
 251   bool Recover = CGOpts.SanitizeRecover.has(SanitizerKind::Memory);
 252   PM.add(createMemorySanitizerPass(TrackOrigins, Recover));
 253
 254   // MemorySanitizer inserts complex instrumentation that mostly follows
 255   // the logic of the original code, but operates on "shadow" values.
 256   // It can benefit from re-running some general purpose optimization passes.
 257   if (Builder.OptLevel > 0) {
 258     PM.add(createEarlyCSEPass());
 259     PM.add(createReassociatePass());
 260     PM.add(createLICMPass());
 261     PM.add(createGVNPass());
 262     PM.add(createInstructionCombiningPass());
 263     PM.add(createDeadStoreEliminationPass());
 264   }
 265 }
 266
 267 static void addThreadSanitizerPass(const PassManagerBuilder &Builder,
 268                                    legacy::PassManagerBase &PM) {
 269   PM.add(createThreadSanitizerPass());
 270 }
 271
 272 static void addDataFlowSanitizerPass(const PassManagerBuilder &Builder,
 273                                      legacy::PassManagerBase &PM) {
 274   const PassManagerBuilderWrapper &BuilderWrapper =
 275       static_cast<const PassManagerBuilderWrapper&>(Builder);
 276   const LangOptions &LangOpts = BuilderWrapper.getLangOpts();
 277   PM.add(createDataFlowSanitizerPass(LangOpts.SanitizerBlacklistFiles));
 278 }
 279
 280 static void addEfficiencySanitizerPass(const PassManagerBuilder &Builder,
 281                                        legacy::PassManagerBase &PM) {
 282   const PassManagerBuilderWrapper &BuilderWrapper =
 283       static_cast<const PassManagerBuilderWrapper&>(Builder);
 284   const LangOptions &LangOpts = BuilderWrapper.getLangOpts();
 285   EfficiencySanitizerOptions Opts;
 286   if (LangOpts.Sanitize.has(SanitizerKind::EfficiencyCacheFrag))
 287     Opts.ToolType = EfficiencySanitizerOptions::ESAN_CacheFrag;
 288   else if (LangOpts.Sanitize.has(SanitizerKind::EfficiencyWorkingSet))
 289     Opts.ToolType = EfficiencySanitizerOptions::ESAN_WorkingSet;
 290   PM.add(createEfficiencySanitizerPass(Opts));
 291 }
 292
 293 static TargetLibraryInfoImpl *createTLII(llvm::Triple &TargetTriple,
 294                                          const CodeGenOptions &CodeGenOpts) {
 295   TargetLibraryInfoImpl *TLII = new TargetLibraryInfoImpl(TargetTriple);
 296   if (!CodeGenOpts.SimplifyLibCalls)
 297     TLII->disableAllFunctions();
 298   else {
 299     // Disable individual libc/libm calls in TargetLibraryInfo.
 300     LibFunc F;
 301     for (auto &FuncName : CodeGenOpts.getNoBuiltinFuncs())
 302       if (TLII->getLibFunc(FuncName, F))
 303         TLII->setUnavailable(F);
 304   }
 305
 306   switch (CodeGenOpts.getVecLib()) {
 307   case CodeGenOptions::Accelerate:
 308     TLII->addVectorizableFunctionsFromVecLib(TargetLibraryInfoImpl::Accelerate);
 309     break;
 310   case CodeGenOptions::SVML:
 311     TLII->addVectorizableFunctionsFromVecLib(TargetLibraryInfoImpl::SVML);
 312     break;
 313   default:
 314     break;
 315   }
 316   return TLII;
 317 }
 318
 319 static void addSymbolRewriterPass(const CodeGenOptions &Opts,
 320                                   legacy::PassManager *MPM) {
 321   llvm::SymbolRewriter::RewriteDescriptorList DL;
 322
 323   llvm::SymbolRewriter::RewriteMapParser MapParser;
 324   for (const auto &MapFile : Opts.RewriteMapFiles)
 325     MapParser.parse(MapFile, &DL);
 326
 327   MPM->add(createRewriteSymbolsPass(DL));
 328 }
 329
 330 static CodeGenOpt::Level getCGOptLevel(const CodeGenOptions &CodeGenOpts) {
 331   switch (CodeGenOpts.OptimizationLevel) {
 332   default:
 333     llvm_unreachable("Invalid optimization level!");
 334   case 0:
 335     return CodeGenOpt::None;
 336   case 1:
 337     return CodeGenOpt::Less;
 338   case 2:
 339     return CodeGenOpt::Default; // O2/Os/Oz
 340   case 3:
 341     return CodeGenOpt::Aggressive;
 342   }
 343 }
 344
 345 static Optional<llvm::CodeModel::Model>
 346 getCodeModel(const CodeGenOptions &CodeGenOpts) {
 347   unsigned CodeModel = llvm::StringSwitch<unsigned>(CodeGenOpts.CodeModel)
 348                            .Case("small", llvm::CodeModel::Small)
 349                            .Case("kernel", llvm::CodeModel::Kernel)
 350                            .Case("medium", llvm::CodeModel::Medium)
 351                            .Case("large", llvm::CodeModel::Large)
 352                            .Case("default", ~1u)
 353                            .Default(~0u);
 354   assert(CodeModel != ~0u && "invalid code model!");
 355   if (CodeModel == ~1u)
 356     return None;
 357   return static_cast<llvm::CodeModel::Model>(CodeModel);
 358 }
 359
 360 static llvm::Reloc::Model getRelocModel(const CodeGenOptions &CodeGenOpts) {
 361   // Keep this synced with the equivalent code in
 362   // lib/Frontend/CompilerInvocation.cpp
 363   llvm::Optional<llvm::Reloc::Model> RM;
 364   RM = llvm::StringSwitch<llvm::Reloc::Model>(CodeGenOpts.RelocationModel)
 365       .Case("static", llvm::Reloc::Static)
 366       .Case("pic", llvm::Reloc::PIC_)
 367       .Case("ropi", llvm::Reloc::ROPI)
 368       .Case("rwpi", llvm::Reloc::RWPI)
 369       .Case("ropi-rwpi", llvm::Reloc::ROPI_RWPI)
 370       .Case("dynamic-no-pic", llvm::Reloc::DynamicNoPIC);
 371   assert(RM.hasValue() && "invalid PIC model!");
 372   return *RM;
 373 }
 374
 375 static TargetMachine::CodeGenFileType getCodeGenFileType(BackendAction Action) {
 376   if (Action == Backend_EmitObj)
 377     return TargetMachine::CGFT_ObjectFile;
 378   else if (Action == Backend_EmitMCNull)
 379     return TargetMachine::CGFT_Null;
 380   else {
 381     assert(Action == Backend_EmitAssembly && "Invalid action!");
 382     return TargetMachine::CGFT_AssemblyFile;
 383   }
 384 }
 385
 386 static void initTargetOptions(llvm::TargetOptions &Options,
 387                               const CodeGenOptions &CodeGenOpts,
 388                               const clang::TargetOptions &TargetOpts,
 389                               const LangOptions &LangOpts,
 390                               const HeaderSearchOptions &HSOpts) {
 391   Options.ThreadModel =
 392       llvm::StringSwitch<llvm::ThreadModel::Model>(CodeGenOpts.ThreadModel)
 393           .Case("posix", llvm::ThreadModel::POSIX)
 394           .Case("single", llvm::ThreadModel::Single);
 395
 396   // Set float ABI type.
 397   assert((CodeGenOpts.FloatABI == "soft" || CodeGenOpts.FloatABI == "softfp" ||
 398           CodeGenOpts.FloatABI == "hard" || CodeGenOpts.FloatABI.empty()) &&
 399          "Invalid Floating Point ABI!");
 400   Options.FloatABIType =
 401       llvm::StringSwitch<llvm::FloatABI::ABIType>(CodeGenOpts.FloatABI)
 402           .Case("soft", llvm::FloatABI::Soft)
 403           .Case("softfp", llvm::FloatABI::Soft)
 404           .Case("hard", llvm::FloatABI::Hard)
 405           .Default(llvm::FloatABI::Default);
 406
 407   // Set FP fusion mode.
 408   switch (LangOpts.getDefaultFPContractMode()) {
 409   case LangOptions::FPC_Off:
 410     // Preserve any contraction performed by the front-end.  (Strict performs
 411     // splitting of the muladd instrinsic in the backend.)
 412     Options.AllowFPOpFusion = llvm::FPOpFusion::Standard;
 413     break;
 414   case LangOptions::FPC_On:
 415     Options.AllowFPOpFusion = llvm::FPOpFusion::Standard;
 416     break;
 417   case LangOptions::FPC_Fast:
 418     Options.AllowFPOpFusion = llvm::FPOpFusion::Fast;
 419     break;
 420   }
 421
 422   Options.UseInitArray = CodeGenOpts.UseInitArray;
 423   Options.DisableIntegratedAS = CodeGenOpts.DisableIntegratedAS;
 424   Options.CompressDebugSections = CodeGenOpts.getCompressDebugSections();
 425   Options.RelaxELFRelocations = CodeGenOpts.RelaxELFRelocations;
 426
 427   // Set EABI version.
 428   Options.EABIVersion = TargetOpts.EABIVersion;
 429
 430   if (LangOpts.SjLjExceptions)
 431     Options.ExceptionModel = llvm::ExceptionHandling::SjLj;
 432   if (LangOpts.SEHExceptions)
 433     Options.ExceptionModel = llvm::ExceptionHandling::WinEH;
 434   if (LangOpts.DWARFExceptions)
 435     Options.ExceptionModel = llvm::ExceptionHandling::DwarfCFI;
 436
 437   Options.NoInfsFPMath = CodeGenOpts.NoInfsFPMath;
 438   Options.NoNaNsFPMath = CodeGenOpts.NoNaNsFPMath;
 439   Options.NoZerosInBSS = CodeGenOpts.NoZeroInitializedInBSS;
 440   Options.UnsafeFPMath = CodeGenOpts.UnsafeFPMath;
 441   Options.StackAlignmentOverride = CodeGenOpts.StackAlignment;
 442   Options.FunctionSections = CodeGenOpts.FunctionSections;
 443   Options.DataSections = CodeGenOpts.DataSections;
 444   Options.UniqueSectionNames = CodeGenOpts.UniqueSectionNames;
 445   Options.EmulatedTLS = CodeGenOpts.EmulatedTLS;
 446   Options.DebuggerTuning = CodeGenOpts.getDebuggerTuning();
 447
 448   if (CodeGenOpts.EnableSplitDwarf)
 449     Options.MCOptions.SplitDwarfFile = CodeGenOpts.SplitDwarfFile;
 450   Options.MCOptions.MCRelaxAll = CodeGenOpts.RelaxAll;
 451   Options.MCOptions.MCSaveTempLabels = CodeGenOpts.SaveTempLabels;
 452   Options.MCOptions.MCUseDwarfDirectory = !CodeGenOpts.NoDwarfDirectoryAsm;
 453   Options.MCOptions.MCNoExecStack = CodeGenOpts.NoExecStack;
 454   Options.MCOptions.MCIncrementalLinkerCompatible =
 455       CodeGenOpts.IncrementalLinkerCompatible;
 456   Options.MCOptions.MCPIECopyRelocations = CodeGenOpts.PIECopyRelocations;
 457   Options.MCOptions.MCFatalWarnings = CodeGenOpts.FatalWarnings;
 458   Options.MCOptions.AsmVerbose = CodeGenOpts.AsmVerbose;
 459   Options.MCOptions.PreserveAsmComments = CodeGenOpts.PreserveAsmComments;
 460   Options.MCOptions.ABIName = TargetOpts.ABI;
 461   for (const auto &Entry : HSOpts.UserEntries)
 462     if (!Entry.IsFramework &&
 463         (Entry.Group == frontend::IncludeDirGroup::Quoted ||
 464          Entry.Group == frontend::IncludeDirGroup::Angled ||
 465          Entry.Group == frontend::IncludeDirGroup::System))
 466       Options.MCOptions.IASSearchPaths.push_back(
 467           Entry.IgnoreSysRoot ? Entry.Path : HSOpts.Sysroot + Entry.Path);
 468 }
 469
 470 void EmitAssemblyHelper::CreatePasses(legacy::PassManager &MPM,
 471                                       legacy::FunctionPassManager &FPM) {
 472   // Handle disabling of all LLVM passes, where we want to preserve the
 473   // internal module before any optimization.
 474   if (CodeGenOpts.DisableLLVMPasses)
 475     return;
 476
 477   // Figure out TargetLibraryInfo.  This needs to be added to MPM and FPM
 478   // manually (and not via PMBuilder), since some passes (eg. InstrProfiling)
 479   // are inserted before PMBuilder ones - they'd get the default-constructed
 480   // TLI with an unknown target otherwise.
 481   Triple TargetTriple(TheModule->getTargetTriple());
 482   std::unique_ptr<TargetLibraryInfoImpl> TLII(
 483       createTLII(TargetTriple, CodeGenOpts));
 484
 485   PassManagerBuilderWrapper PMBuilder(TargetTriple, CodeGenOpts, LangOpts);
 486
 487   // At O0 and O1 we only run the always inliner which is more efficient. At
 488   // higher optimization levels we run the normal inliner.
 489   if (CodeGenOpts.OptimizationLevel <= 1) {
 490     bool InsertLifetimeIntrinsics = (CodeGenOpts.OptimizationLevel != 0 &&
 491                                      !CodeGenOpts.DisableLifetimeMarkers);
 492     PMBuilder.Inliner = createAlwaysInlinerLegacyPass(InsertLifetimeIntrinsics);
 493   } else {
 494     // We do not want to inline hot callsites for SamplePGO module-summary build
 495     // because profile annotation will happen again in ThinLTO backend, and we
 496     // want the IR of the hot path to match the profile.
 497     PMBuilder.Inliner = createFunctionInliningPass(
 498         CodeGenOpts.OptimizationLevel, CodeGenOpts.OptimizeSize,
 499         (!CodeGenOpts.SampleProfileFile.empty() &&
 500          CodeGenOpts.EmitSummaryIndex));
 501   }
 502
 503   PMBuilder.OptLevel = CodeGenOpts.OptimizationLevel;
 504   PMBuilder.SizeLevel = CodeGenOpts.OptimizeSize;
 505   PMBuilder.SLPVectorize = CodeGenOpts.VectorizeSLP;
 506   PMBuilder.LoopVectorize = CodeGenOpts.VectorizeLoop;
 507
 508   PMBuilder.DisableUnrollLoops = !CodeGenOpts.UnrollLoops;
 509   PMBuilder.MergeFunctions = CodeGenOpts.MergeFunctions;
 510   PMBuilder.PrepareForThinLTO = CodeGenOpts.EmitSummaryIndex;
 511   PMBuilder.PrepareForLTO = CodeGenOpts.PrepareForLTO;
 512   PMBuilder.RerollLoops = CodeGenOpts.RerollLoops;
 513
 514   MPM.add(new TargetLibraryInfoWrapperPass(*TLII));
 515
 516   if (TM)
 517     TM->adjustPassManager(PMBuilder);
 518
 519   if (CodeGenOpts.DebugInfoForProfiling ||
 520       !CodeGenOpts.SampleProfileFile.empty())
 521     PMBuilder.addExtension(PassManagerBuilder::EP_EarlyAsPossible,
 522                            addAddDiscriminatorsPass);
 523
 524   // In ObjC ARC mode, add the main ARC optimization passes.
 525   if (LangOpts.ObjCAutoRefCount) {
 526     PMBuilder.addExtension(PassManagerBuilder::EP_EarlyAsPossible,
 527                            addObjCARCExpandPass);
 528     PMBuilder.addExtension(PassManagerBuilder::EP_ModuleOptimizerEarly,
 529                            addObjCARCAPElimPass);
 530     PMBuilder.addExtension(PassManagerBuilder::EP_ScalarOptimizerLate,
 531                            addObjCARCOptPass);
 532   }
 533
 534   if (LangOpts.Sanitize.has(SanitizerKind::LocalBounds)) {
 535     PMBuilder.addExtension(PassManagerBuilder::EP_ScalarOptimizerLate,
 536                            addBoundsCheckingPass);
 537     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
 538                            addBoundsCheckingPass);
 539   }
 540
 541   if (CodeGenOpts.SanitizeCoverageType ||
 542       CodeGenOpts.SanitizeCoverageIndirectCalls ||
 543       CodeGenOpts.SanitizeCoverageTraceCmp) {
 544     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
 545                            addSanitizerCoveragePass);
 546     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
 547                            addSanitizerCoveragePass);
 548   }
 549
 550   if (LangOpts.Sanitize.has(SanitizerKind::Address)) {
 551     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
 552                            addAddressSanitizerPasses);
 553     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
 554                            addAddressSanitizerPasses);
 555   }
 556
 557   if (LangOpts.Sanitize.has(SanitizerKind::KernelAddress)) {
 558     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
 559                            addKernelAddressSanitizerPasses);
 560     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
 561                            addKernelAddressSanitizerPasses);
 562   }
 563
 564   if (LangOpts.Sanitize.has(SanitizerKind::HWAddress)) {
 565     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
 566                            addHWAddressSanitizerPasses);
 567     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
 568                            addHWAddressSanitizerPasses);
 569   }
 570
 571   if (LangOpts.Sanitize.has(SanitizerKind::Memory)) {
 572     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
 573                            addMemorySanitizerPass);
 574     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
 575                            addMemorySanitizerPass);
 576   }
 577
 578   if (LangOpts.Sanitize.has(SanitizerKind::Thread)) {
 579     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
 580                            addThreadSanitizerPass);
 581     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
 582                            addThreadSanitizerPass);
 583   }
 584
 585   if (LangOpts.Sanitize.has(SanitizerKind::DataFlow)) {
 586     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
 587                            addDataFlowSanitizerPass);
 588     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
 589                            addDataFlowSanitizerPass);
 590   }
 591
 592   if (LangOpts.CoroutinesTS)
 593     addCoroutinePassesToExtensionPoints(PMBuilder);
 594
 595   if (LangOpts.Sanitize.hasOneOf(SanitizerKind::Efficiency)) {
 596     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
 597                            addEfficiencySanitizerPass);
 598     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
 599                            addEfficiencySanitizerPass);
 600   }
 601
 602   // Set up the per-function pass manager.
 603   FPM.add(new TargetLibraryInfoWrapperPass(*TLII));
 604   if (CodeGenOpts.VerifyModule)
 605     FPM.add(createVerifierPass());
 606
 607   // Set up the per-module pass manager.
 608   if (!CodeGenOpts.RewriteMapFiles.empty())
 609     addSymbolRewriterPass(CodeGenOpts, &MPM);
 610
 611   if (!CodeGenOpts.DisableGCov &&
 612       (CodeGenOpts.EmitGcovArcs || CodeGenOpts.EmitGcovNotes)) {
 613     // Not using 'GCOVOptions::getDefault' allows us to avoid exiting if
 614     // LLVM's -default-gcov-version flag is set to something invalid.
 615     GCOVOptions Options;
 616     Options.EmitNotes = CodeGenOpts.EmitGcovNotes;
 617     Options.EmitData = CodeGenOpts.EmitGcovArcs;
 618     memcpy(Options.Version, CodeGenOpts.CoverageVersion, 4);
 619     Options.UseCfgChecksum = CodeGenOpts.CoverageExtraChecksum;
 620     Options.NoRedZone = CodeGenOpts.DisableRedZone;
 621     Options.FunctionNamesInData =
 622         !CodeGenOpts.CoverageNoFunctionNamesInData;
 623     Options.ExitBlockBeforeBody = CodeGenOpts.CoverageExitBlockBeforeBody;
 624     MPM.add(createGCOVProfilerPass(Options));
 625     if (CodeGenOpts.getDebugInfo() == codegenoptions::NoDebugInfo)
 626       MPM.add(createStripSymbolsPass(true));
 627   }
 628
 629   if (CodeGenOpts.hasProfileClangInstr()) {
 630     InstrProfOptions Options;
 631     Options.NoRedZone = CodeGenOpts.DisableRedZone;
 632     Options.InstrProfileOutput = CodeGenOpts.InstrProfileOutput;
 633     MPM.add(createInstrProfilingLegacyPass(Options));
 634   }
 635   if (CodeGenOpts.hasProfileIRInstr()) {
 636     PMBuilder.EnablePGOInstrGen = true;
 637     if (!CodeGenOpts.InstrProfileOutput.empty())
 638       PMBuilder.PGOInstrGen = CodeGenOpts.InstrProfileOutput;
 639     else
 640       PMBuilder.PGOInstrGen = DefaultProfileGenName;
 641   }
 642   if (CodeGenOpts.hasProfileIRUse())
 643     PMBuilder.PGOInstrUse = CodeGenOpts.ProfileInstrumentUsePath;
 644
 645   if (!CodeGenOpts.SampleProfileFile.empty())
 646     PMBuilder.PGOSampleUse = CodeGenOpts.SampleProfileFile;
 647
 648   PMBuilder.populateFunctionPassManager(FPM);
 649   PMBuilder.populateModulePassManager(MPM);
 650 }
 651
 652 static void setCommandLineOpts(const CodeGenOptions &CodeGenOpts) {
 653   SmallVector<const char *, 16> BackendArgs;
 654   BackendArgs.push_back("clang"); // Fake program name.
 655   if (!CodeGenOpts.DebugPass.empty()) {
 656     BackendArgs.push_back("-debug-pass");
 657     BackendArgs.push_back(CodeGenOpts.DebugPass.c_str());
 658   }
 659   if (!CodeGenOpts.LimitFloatPrecision.empty()) {
 660     BackendArgs.push_back("-limit-float-precision");
 661     BackendArgs.push_back(CodeGenOpts.LimitFloatPrecision.c_str());
 662   }
 663   for (const std::string &BackendOption : CodeGenOpts.BackendOptions)
 664     BackendArgs.push_back(BackendOption.c_str());
 665   BackendArgs.push_back(nullptr);
 666   llvm::cl::ParseCommandLineOptions(BackendArgs.size() - 1,
 667                                     BackendArgs.data());
 668 }
 669
 670 void EmitAssemblyHelper::CreateTargetMachine(bool MustCreateTM) {
 671   // Create the TargetMachine for generating code.
 672   std::string Error;
 673   std::string Triple = TheModule->getTargetTriple();
 674   const llvm::Target *TheTarget = TargetRegistry::lookupTarget(Triple, Error);
 675   if (!TheTarget) {
 676     if (MustCreateTM)
 677       Diags.Report(diag::err_fe_unable_to_create_target) << Error;
 678     return;
 679   }
 680
 681   Optional<llvm::CodeModel::Model> CM = getCodeModel(CodeGenOpts);
 682   std::string FeaturesStr =
 683       llvm::join(TargetOpts.Features.begin(), TargetOpts.Features.end(), ",");
 684   llvm::Reloc::Model RM = getRelocModel(CodeGenOpts);
 685   CodeGenOpt::Level OptLevel = getCGOptLevel(CodeGenOpts);
 686
 687   llvm::TargetOptions Options;
 688   initTargetOptions(Options, CodeGenOpts, TargetOpts, LangOpts, HSOpts);
 689   TM.reset(TheTarget->createTargetMachine(Triple, TargetOpts.CPU, FeaturesStr,
 690                                           Options, RM, CM, OptLevel));
 691 }
 692
 693 bool EmitAssemblyHelper::AddEmitPasses(legacy::PassManager &CodeGenPasses,
 694                                        BackendAction Action,
 695                                        raw_pwrite_stream &OS) {
 696   // Add LibraryInfo.
 697   llvm::Triple TargetTriple(TheModule->getTargetTriple());
 698   std::unique_ptr<TargetLibraryInfoImpl> TLII(
 699       createTLII(TargetTriple, CodeGenOpts));
 700   CodeGenPasses.add(new TargetLibraryInfoWrapperPass(*TLII));
 701
 702   // Normal mode, emit a .s or .o file by running the code generator. Note,
 703   // this also adds codegenerator level optimization passes.
 704   TargetMachine::CodeGenFileType CGFT = getCodeGenFileType(Action);
 705
 706   // Add ObjC ARC final-cleanup optimizations. This is done as part of the
 707   // "codegen" passes so that it isn't run multiple times when there is
 708   // inlining happening.
 709   if (CodeGenOpts.OptimizationLevel > 0)
 710     CodeGenPasses.add(createObjCARCContractPass());
 711
 712   if (TM->addPassesToEmitFile(CodeGenPasses, OS, CGFT,
 713                               /*DisableVerify=*/!CodeGenOpts.VerifyModule)) {
 714     Diags.Report(diag::err_fe_unable_to_interface_with_target);
 715     return false;
 716   }
 717
 718   return true;
 719 }
 720
 721 void EmitAssemblyHelper::EmitAssembly(BackendAction Action,
 722                                       std::unique_ptr<raw_pwrite_stream> OS) {
 723   TimeRegion Region(llvm::TimePassesIsEnabled ? &CodeGenerationTime : nullptr);
 724
 725   setCommandLineOpts(CodeGenOpts);
 726
 727   bool UsesCodeGen = (Action != Backend_EmitNothing &&
 728                       Action != Backend_EmitBC &&
 729                       Action != Backend_EmitLL);
 730   CreateTargetMachine(UsesCodeGen);
 731
 732   if (UsesCodeGen && !TM)
 733     return;
 734   if (TM)
 735     TheModule->setDataLayout(TM->createDataLayout());
 736
 737   legacy::PassManager PerModulePasses;
 738   PerModulePasses.add(
 739       createTargetTransformInfoWrapperPass(getTargetIRAnalysis()));
 740
 741   legacy::FunctionPassManager PerFunctionPasses(TheModule);
 742   PerFunctionPasses.add(
 743       createTargetTransformInfoWrapperPass(getTargetIRAnalysis()));
 744
 745   CreatePasses(PerModulePasses, PerFunctionPasses);
 746
 747   legacy::PassManager CodeGenPasses;
 748   CodeGenPasses.add(
 749       createTargetTransformInfoWrapperPass(getTargetIRAnalysis()));
 750
 751   std::unique_ptr<raw_fd_ostream> ThinLinkOS;
 752
 753   switch (Action) {
 754   case Backend_EmitNothing:
 755     break;
 756
 757   case Backend_EmitBC:
 758     if (CodeGenOpts.EmitSummaryIndex) {
 759       if (!CodeGenOpts.ThinLinkBitcodeFile.empty()) {
 760         std::error_code EC;
 761         ThinLinkOS.reset(new llvm::raw_fd_ostream(
 762             CodeGenOpts.ThinLinkBitcodeFile, EC,
 763             llvm::sys::fs::F_None));
 764         if (EC) {
 765           Diags.Report(diag::err_fe_unable_to_open_output) << CodeGenOpts.ThinLinkBitcodeFile
 766                                                            << EC.message();
 767           return;
 768         }
 769       }
 770       PerModulePasses.add(
 771           createWriteThinLTOBitcodePass(*OS, ThinLinkOS.get()));
 772     }
 773     else
 774       PerModulePasses.add(
 775           createBitcodeWriterPass(*OS, CodeGenOpts.EmitLLVMUseLists));
 776     break;
 777
 778   case Backend_EmitLL:
 779     PerModulePasses.add(
 780         createPrintModulePass(*OS, "", CodeGenOpts.EmitLLVMUseLists));
 781     break;
 782
 783   default:
 784     if (!AddEmitPasses(CodeGenPasses, Action, *OS))
 785       return;
 786   }
 787
 788   // Before executing passes, print the final values of the LLVM options.
 789   cl::PrintOptionValues();
 790
 791   // Run passes. For now we do all passes at once, but eventually we
 792   // would like to have the option of streaming code generation.
 793
 794   {
 795     PrettyStackTraceString CrashInfo("Per-function optimization");
 796
 797     PerFunctionPasses.doInitialization();
 798     for (Function &F : *TheModule)
 799       if (!F.isDeclaration())
 800         PerFunctionPasses.run(F);
 801     PerFunctionPasses.doFinalization();
 802   }
 803
 804   {
 805     PrettyStackTraceString CrashInfo("Per-module optimization passes");
 806     PerModulePasses.run(*TheModule);
 807   }
 808
 809   {
 810     PrettyStackTraceString CrashInfo("Code generation");
 811     CodeGenPasses.run(*TheModule);
 812   }
 813 }
 814
 815 static PassBuilder::OptimizationLevel mapToLevel(const CodeGenOptions &Opts) {
 816   switch (Opts.OptimizationLevel) {
 817   default:
 818     llvm_unreachable("Invalid optimization level!");
 819
 820   case 1:
 821     return PassBuilder::O1;
 822
 823   case 2:
 824     switch (Opts.OptimizeSize) {
 825     default:
 826       llvm_unreachable("Invalide optimization level for size!");
 827
 828     case 0:
 829       return PassBuilder::O2;
 830
 831     case 1:
 832       return PassBuilder::Os;
 833
 834     case 2:
 835       return PassBuilder::Oz;
 836     }
 837
 838   case 3:
 839     return PassBuilder::O3;
 840   }
 841 }
 842
 843 /// A clean version of `EmitAssembly` that uses the new pass manager.
 844 ///
 845 /// Not all features are currently supported in this system, but where
 846 /// necessary it falls back to the legacy pass manager to at least provide
 847 /// basic functionality.
 848 ///
 849 /// This API is planned to have its functionality finished and then to replace
 850 /// `EmitAssembly` at some point in the future when the default switches.
 851 void EmitAssemblyHelper::EmitAssemblyWithNewPassManager(
 852     BackendAction Action, std::unique_ptr<raw_pwrite_stream> OS) {
 853   TimeRegion Region(llvm::TimePassesIsEnabled ? &CodeGenerationTime : nullptr);
 854   setCommandLineOpts(CodeGenOpts);
 855
 856   // The new pass manager always makes a target machine available to passes
 857   // during construction.
 858   CreateTargetMachine(/*MustCreateTM*/ true);
 859   if (!TM)
 860     // This will already be diagnosed, just bail.
 861     return;
 862   TheModule->setDataLayout(TM->createDataLayout());
 863
 864   Optional<PGOOptions> PGOOpt;
 865
 866   if (CodeGenOpts.hasProfileIRInstr())
 867     // -fprofile-generate.
 868     PGOOpt = PGOOptions(CodeGenOpts.InstrProfileOutput.empty()
 869                             ? DefaultProfileGenName
 870                             : CodeGenOpts.InstrProfileOutput,
 871                         "", "", true, CodeGenOpts.DebugInfoForProfiling);
 872   else if (CodeGenOpts.hasProfileIRUse())
 873     // -fprofile-use.
 874     PGOOpt = PGOOptions("", CodeGenOpts.ProfileInstrumentUsePath, "", false,
 875                         CodeGenOpts.DebugInfoForProfiling);
 876   else if (!CodeGenOpts.SampleProfileFile.empty())
 877     // -fprofile-sample-use
 878     PGOOpt = PGOOptions("", "", CodeGenOpts.SampleProfileFile, false,
 879                         CodeGenOpts.DebugInfoForProfiling);
 880   else if (CodeGenOpts.DebugInfoForProfiling)
 881     // -fdebug-info-for-profiling
 882     PGOOpt = PGOOptions("", "", "", false, true);
 883
 884   PassBuilder PB(TM.get(), PGOOpt);
 885
 886   LoopAnalysisManager LAM(CodeGenOpts.DebugPassManager);
 887   FunctionAnalysisManager FAM(CodeGenOpts.DebugPassManager);
 888   CGSCCAnalysisManager CGAM(CodeGenOpts.DebugPassManager);
 889   ModuleAnalysisManager MAM(CodeGenOpts.DebugPassManager);
 890
 891   // Register the AA manager first so that our version is the one used.
 892   FAM.registerPass([&] { return PB.buildDefaultAAPipeline(); });
 893
 894   // Register the target library analysis directly and give it a customized
 895   // preset TLI.
 896   Triple TargetTriple(TheModule->getTargetTriple());
 897   std::unique_ptr<TargetLibraryInfoImpl> TLII(
 898       createTLII(TargetTriple, CodeGenOpts));
 899   FAM.registerPass([&] { return TargetLibraryAnalysis(*TLII); });
 900   MAM.registerPass([&] { return TargetLibraryAnalysis(*TLII); });
 901
 902   // Register all the basic analyses with the managers.
 903   PB.registerModuleAnalyses(MAM);
 904   PB.registerCGSCCAnalyses(CGAM);
 905   PB.registerFunctionAnalyses(FAM);
 906   PB.registerLoopAnalyses(LAM);
 907   PB.crossRegisterProxies(LAM, FAM, CGAM, MAM);
 908
 909   ModulePassManager MPM(CodeGenOpts.DebugPassManager);
 910
 911   if (!CodeGenOpts.DisableLLVMPasses) {
 912     bool IsThinLTO = CodeGenOpts.EmitSummaryIndex;
 913     bool IsLTO = CodeGenOpts.PrepareForLTO;
 914
 915     if (CodeGenOpts.OptimizationLevel == 0) {
 916       // Build a minimal pipeline based on the semantics required by Clang,
 917       // which is just that always inlining occurs.
 918       MPM.addPass(AlwaysInlinerPass());
 919
 920       // At -O0 we directly run necessary sanitizer passes.
 921       if (LangOpts.Sanitize.has(SanitizerKind::LocalBounds))
 922         MPM.addPass(createModuleToFunctionPassAdaptor(BoundsCheckingPass()));
 923
 924       // Lastly, add a semantically necessary pass for ThinLTO.
 925       if (IsThinLTO)
 926         MPM.addPass(NameAnonGlobalPass());
 927     } else {
 928       // Map our optimization levels into one of the distinct levels used to
 929       // configure the pipeline.
 930       PassBuilder::OptimizationLevel Level = mapToLevel(CodeGenOpts);
 931
 932       // Register callbacks to schedule sanitizer passes at the appropriate part of
 933       // the pipeline.
 934       if (LangOpts.Sanitize.has(SanitizerKind::LocalBounds))
 935         PB.registerScalarOptimizerLateEPCallback(
 936             [](FunctionPassManager &FPM, PassBuilder::OptimizationLevel Level) {
 937               FPM.addPass(BoundsCheckingPass());
 938             });
 939
 940       if (IsThinLTO) {
 941         MPM = PB.buildThinLTOPreLinkDefaultPipeline(
 942             Level, CodeGenOpts.DebugPassManager);
 943         MPM.addPass(NameAnonGlobalPass());
 944       } else if (IsLTO) {
 945         MPM = PB.buildLTOPreLinkDefaultPipeline(Level,
 946                                                 CodeGenOpts.DebugPassManager);
 947       } else {
 948         MPM = PB.buildPerModuleDefaultPipeline(Level,
 949                                                CodeGenOpts.DebugPassManager);
 950       }
 951     }
 952   }
 953
 954   // FIXME: We still use the legacy pass manager to do code generation. We
 955   // create that pass manager here and use it as needed below.
 956   legacy::PassManager CodeGenPasses;
 957   bool NeedCodeGen = false;
 958   Optional<raw_fd_ostream> ThinLinkOS;
 959
 960   // Append any output we need to the pass manager.
 961   switch (Action) {
 962   case Backend_EmitNothing:
 963     break;
 964
 965   case Backend_EmitBC:
 966     if (CodeGenOpts.EmitSummaryIndex) {
 967       if (!CodeGenOpts.ThinLinkBitcodeFile.empty()) {
 968         std::error_code EC;
 969         ThinLinkOS.emplace(CodeGenOpts.ThinLinkBitcodeFile, EC,
 970                            llvm::sys::fs::F_None);
 971         if (EC) {
 972           Diags.Report(diag::err_fe_unable_to_open_output)
 973               << CodeGenOpts.ThinLinkBitcodeFile << EC.message();
 974           return;
 975         }
 976       }
 977       MPM.addPass(
 978           ThinLTOBitcodeWriterPass(*OS, ThinLinkOS ? &*ThinLinkOS : nullptr));
 979     } else {
 980       MPM.addPass(BitcodeWriterPass(*OS, CodeGenOpts.EmitLLVMUseLists,
 981                                     CodeGenOpts.EmitSummaryIndex,
 982                                     CodeGenOpts.EmitSummaryIndex));
 983     }
 984     break;
 985
 986   case Backend_EmitLL:
 987     MPM.addPass(PrintModulePass(*OS, "", CodeGenOpts.EmitLLVMUseLists));
 988     break;
 989
 990   case Backend_EmitAssembly:
 991   case Backend_EmitMCNull:
 992   case Backend_EmitObj:
 993     NeedCodeGen = true;
 994     CodeGenPasses.add(
 995         createTargetTransformInfoWrapperPass(getTargetIRAnalysis()));
 996     if (!AddEmitPasses(CodeGenPasses, Action, *OS))
 997       // FIXME: Should we handle this error differently?
 998       return;
 999     break;
1000   }
1001
1002   // Before executing passes, print the final values of the LLVM options.
1003   cl::PrintOptionValues();
1004
1005   // Now that we have all of the passes ready, run them.
1006   {
1007     PrettyStackTraceString CrashInfo("Optimizer");
1008     MPM.run(*TheModule, MAM);
1009   }
1010
1011   // Now if needed, run the legacy PM for codegen.
1012   if (NeedCodeGen) {
1013     PrettyStackTraceString CrashInfo("Code generation");
1014     CodeGenPasses.run(*TheModule);
1015   }
1016 }
1017
1018 Expected<BitcodeModule> clang::FindThinLTOModule(MemoryBufferRef MBRef) {
1019   Expected<std::vector<BitcodeModule>> BMsOrErr = getBitcodeModuleList(MBRef);
1020   if (!BMsOrErr)
1021     return BMsOrErr.takeError();
1022
1023   // The bitcode file may contain multiple modules, we want the one that is
1024   // marked as being the ThinLTO module.
1025   for (BitcodeModule &BM : *BMsOrErr) {
1026     Expected<BitcodeLTOInfo> LTOInfo = BM.getLTOInfo();
1027     if (LTOInfo && LTOInfo->IsThinLTO)
1028       return BM;
1029   }
1030
1031   return make_error<StringError>("Could not find module summary",
1032                                  inconvertibleErrorCode());
1033 }
1034
1035 static void runThinLTOBackend(ModuleSummaryIndex *CombinedIndex, Module *M,
1036                               const HeaderSearchOptions &HeaderOpts,
1037                               const CodeGenOptions &CGOpts,
1038                               const clang::TargetOptions &TOpts,
1039                               const LangOptions &LOpts,
1040                               std::unique_ptr<raw_pwrite_stream> OS,
1041                               std::string SampleProfile,
1042                               BackendAction Action) {
1043   StringMap<DenseMap<GlobalValue::GUID, GlobalValueSummary *>>
1044       ModuleToDefinedGVSummaries;
1045   CombinedIndex->collectDefinedGVSummariesPerModule(ModuleToDefinedGVSummaries);
1046
1047   setCommandLineOpts(CGOpts);
1048
1049   // We can simply import the values mentioned in the combined index, since
1050   // we should only invoke this using the individual indexes written out
1051   // via a WriteIndexesThinBackend.
1052   FunctionImporter::ImportMapTy ImportList;
1053   for (auto &GlobalList : *CombinedIndex) {
1054     // Ignore entries for undefined references.
1055     if (GlobalList.second.SummaryList.empty())
1056       continue;
1057
1058     auto GUID = GlobalList.first;
1059     assert(GlobalList.second.SummaryList.size() == 1 &&
1060            "Expected individual combined index to have one summary per GUID");
1061     auto &Summary = GlobalList.second.SummaryList[0];
1062     // Skip the summaries for the importing module. These are included to
1063     // e.g. record required linkage changes.
1064     if (Summary->modulePath() == M->getModuleIdentifier())
1065       continue;
1066     // Doesn't matter what value we plug in to the map, just needs an entry
1067     // to provoke importing by thinBackend.
1068     ImportList[Summary->modulePath()][GUID] = 1;
1069   }
1070
1071   std::vector<std::unique_ptr<llvm::MemoryBuffer>> OwnedImports;
1072   MapVector<llvm::StringRef, llvm::BitcodeModule> ModuleMap;
1073
1074   for (auto &I : ImportList) {
1075     ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> MBOrErr =
1076         llvm::MemoryBuffer::getFile(I.first());
1077     if (!MBOrErr) {
1078       errs() << "Error loading imported file '" << I.first()
1079              << "': " << MBOrErr.getError().message() << "\n";
1080       return;
1081     }
1082
1083     Expected<BitcodeModule> BMOrErr = FindThinLTOModule(**MBOrErr);
1084     if (!BMOrErr) {
1085       handleAllErrors(BMOrErr.takeError(), [&](ErrorInfoBase &EIB) {
1086         errs() << "Error loading imported file '" << I.first()
1087                << "': " << EIB.message() << '\n';
1088       });
1089       return;
1090     }
1091     ModuleMap.insert({I.first(), *BMOrErr});
1092
1093     OwnedImports.push_back(std::move(*MBOrErr));
1094   }
1095   auto AddStream = [&](size_t Task) {
1096     return llvm::make_unique<lto::NativeObjectStream>(std::move(OS));
1097   };
1098   lto::Config Conf;
1099   Conf.CPU = TOpts.CPU;
1100   Conf.CodeModel = getCodeModel(CGOpts);
1101   Conf.MAttrs = TOpts.Features;
1102   Conf.RelocModel = getRelocModel(CGOpts);
1103   Conf.CGOptLevel = getCGOptLevel(CGOpts);
1104   initTargetOptions(Conf.Options, CGOpts, TOpts, LOpts, HeaderOpts);
1105   Conf.SampleProfile = std::move(SampleProfile);
1106   Conf.UseNewPM = CGOpts.ExperimentalNewPassManager;
1107   Conf.DebugPassManager = CGOpts.DebugPassManager;
1108   switch (Action) {
1109   case Backend_EmitNothing:
1110     Conf.PreCodeGenModuleHook = [](size_t Task, const Module &Mod) {
1111       return false;
1112     };
1113     break;
1114   case Backend_EmitLL:
1115     Conf.PreCodeGenModuleHook = [&](size_t Task, const Module &Mod) {
1116       M->print(*OS, nullptr, CGOpts.EmitLLVMUseLists);
1117       return false;
1118     };
1119     break;
1120   case Backend_EmitBC:
1121     Conf.PreCodeGenModuleHook = [&](size_t Task, const Module &Mod) {
1122       WriteBitcodeToFile(M, *OS, CGOpts.EmitLLVMUseLists);
1123       return false;
1124     };
1125     break;
1126   default:
1127     Conf.CGFileType = getCodeGenFileType(Action);
1128     break;
1129   }
1130   if (Error E = thinBackend(
1131           Conf, 0, AddStream, *M, *CombinedIndex, ImportList,
1132           ModuleToDefinedGVSummaries[M->getModuleIdentifier()], ModuleMap)) {
1133     handleAllErrors(std::move(E), [&](ErrorInfoBase &EIB) {
1134       errs() << "Error running ThinLTO backend: " << EIB.message() << '\n';
1135     });
1136   }
1137 }
1138
1139 void clang::EmitBackendOutput(DiagnosticsEngine &Diags,
1140                               const HeaderSearchOptions &HeaderOpts,
1141                               const CodeGenOptions &CGOpts,
1142                               const clang::TargetOptions &TOpts,
1143                               const LangOptions &LOpts,
1144                               const llvm::DataLayout &TDesc, Module *M,
1145                               BackendAction Action,
1146                               std::unique_ptr<raw_pwrite_stream> OS) {
1147   if (!CGOpts.ThinLTOIndexFile.empty()) {
1148     // If we are performing a ThinLTO importing compile, load the function index
1149     // into memory and pass it into runThinLTOBackend, which will run the
1150     // function importer and invoke LTO passes.
1151     Expected<std::unique_ptr<ModuleSummaryIndex>> IndexOrErr =
1152         llvm::getModuleSummaryIndexForFile(CGOpts.ThinLTOIndexFile,
1153                                            /*IgnoreEmptyThinLTOIndexFile*/true);
1154     if (!IndexOrErr) {
1155       logAllUnhandledErrors(IndexOrErr.takeError(), errs(),
1156                             "Error loading index file '" +
1157                             CGOpts.ThinLTOIndexFile + "': ");
1158       return;
1159     }
1160     std::unique_ptr<ModuleSummaryIndex> CombinedIndex = std::move(*IndexOrErr);
1161     // A null CombinedIndex means we should skip ThinLTO compilation
1162     // (LLVM will optionally ignore empty index files, returning null instead
1163     // of an error).
1164     bool DoThinLTOBackend = CombinedIndex != nullptr;
1165     if (DoThinLTOBackend) {
1166       runThinLTOBackend(CombinedIndex.get(), M, HeaderOpts, CGOpts, TOpts,
1167                         LOpts, std::move(OS), CGOpts.SampleProfileFile, Action);
1168       return;
1169     }
1170   }
1171
1172   EmitAssemblyHelper AsmHelper(Diags, HeaderOpts, CGOpts, TOpts, LOpts, M);
1173
1174   if (CGOpts.ExperimentalNewPassManager)
1175     AsmHelper.EmitAssemblyWithNewPassManager(Action, std::move(OS));
1176   else
1177     AsmHelper.EmitAssembly(Action, std::move(OS));
1178
1179   // Verify clang's TargetInfo DataLayout against the LLVM TargetMachine's
1180   // DataLayout.
1181   if (AsmHelper.TM) {
1182     std::string DLDesc = M->getDataLayout().getStringRepresentation();
1183     if (DLDesc != TDesc.getStringRepresentation()) {
1184       unsigned DiagID = Diags.getCustomDiagID(
1185           DiagnosticsEngine::Error, "backend data layout '%0' does not match "
1186                                     "expected target description '%1'");
1187       Diags.Report(DiagID) << DLDesc << TDesc.getStringRepresentation();
1188     }
1189   }
1190 }
1191
1192 static const char* getSectionNameForBitcode(const Triple &T) {
1193   switch (T.getObjectFormat()) {
1194   case Triple::MachO:
1195     return "__LLVM,__bitcode";
1196   case Triple::COFF:
1197   case Triple::ELF:
1198   case Triple::Wasm:
1199   case Triple::UnknownObjectFormat:
1200     return ".llvmbc";
1201   }
1202   llvm_unreachable("Unimplemented ObjectFormatType");
1203 }
1204
1205 static const char* getSectionNameForCommandline(const Triple &T) {
1206   switch (T.getObjectFormat()) {
1207   case Triple::MachO:
1208     return "__LLVM,__cmdline";
1209   case Triple::COFF:
1210   case Triple::ELF:
1211   case Triple::Wasm:
1212   case Triple::UnknownObjectFormat:
1213     return ".llvmcmd";
1214   }
1215   llvm_unreachable("Unimplemented ObjectFormatType");
1216 }
1217
1218 // With -fembed-bitcode, save a copy of the llvm IR as data in the
1219 // __LLVM,__bitcode section.
1220 void clang::EmbedBitcode(llvm::Module *M, const CodeGenOptions &CGOpts,
1221                          llvm::MemoryBufferRef Buf) {
1222   if (CGOpts.getEmbedBitcode() == CodeGenOptions::Embed_Off)
1223     return;
1224
1225   // Save llvm.compiler.used and remote it.
1226   SmallVector<Constant*, 2> UsedArray;
1227   SmallSet<GlobalValue*, 4> UsedGlobals;
1228   Type *UsedElementType = Type::getInt8Ty(M->getContext())->getPointerTo(0);
1229   GlobalVariable *Used = collectUsedGlobalVariables(*M, UsedGlobals, true);
1230   for (auto *GV : UsedGlobals) {
1231     if (GV->getName() != "llvm.embedded.module" &&
1232         GV->getName() != "llvm.cmdline")
1233       UsedArray.push_back(
1234           ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
1235   }
1236   if (Used)
1237     Used->eraseFromParent();
1238
1239   // Embed the bitcode for the llvm module.
1240   std::string Data;
1241   ArrayRef<uint8_t> ModuleData;
1242   Triple T(M->getTargetTriple());
1243   // Create a constant that contains the bitcode.
1244   // In case of embedding a marker, ignore the input Buf and use the empty
1245   // ArrayRef. It is also legal to create a bitcode marker even Buf is empty.
1246   if (CGOpts.getEmbedBitcode() != CodeGenOptions::Embed_Marker) {
1247     if (!isBitcode((const unsigned char *)Buf.getBufferStart(),
1248                    (const unsigned char *)Buf.getBufferEnd())) {
1249       // If the input is LLVM Assembly, bitcode is produced by serializing
1250       // the module. Use-lists order need to be perserved in this case.
1251       llvm::raw_string_ostream OS(Data);
1252       llvm::WriteBitcodeToFile(M, OS, /* ShouldPreserveUseListOrder */ true);
1253       ModuleData =
1254           ArrayRef<uint8_t>((const uint8_t *)OS.str().data(), OS.str().size());
1255     } else
1256       // If the input is LLVM bitcode, write the input byte stream directly.
1257       ModuleData = ArrayRef<uint8_t>((const uint8_t *)Buf.getBufferStart(),
1258                                      Buf.getBufferSize());
1259   }
1260   llvm::Constant *ModuleConstant =
1261       llvm::ConstantDataArray::get(M->getContext(), ModuleData);
1262   llvm::GlobalVariable *GV = new llvm::GlobalVariable(
1263       *M, ModuleConstant->getType(), true, llvm::GlobalValue::PrivateLinkage,
1264       ModuleConstant);
1265   GV->setSection(getSectionNameForBitcode(T));
1266   UsedArray.push_back(
1267       ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
1268   if (llvm::GlobalVariable *Old =
1269           M->getGlobalVariable("llvm.embedded.module", true)) {
1270     assert(Old->hasOneUse() &&
1271            "llvm.embedded.module can only be used once in llvm.compiler.used");
1272     GV->takeName(Old);
1273     Old->eraseFromParent();
1274   } else {
1275     GV->setName("llvm.embedded.module");
1276   }
1277
1278   // Skip if only bitcode needs to be embedded.
1279   if (CGOpts.getEmbedBitcode() != CodeGenOptions::Embed_Bitcode) {
1280     // Embed command-line options.
1281     ArrayRef<uint8_t> CmdData(const_cast<uint8_t *>(CGOpts.CmdArgs.data()),
1282                               CGOpts.CmdArgs.size());
1283     llvm::Constant *CmdConstant =
1284       llvm::ConstantDataArray::get(M->getContext(), CmdData);
1285     GV = new llvm::GlobalVariable(*M, CmdConstant->getType(), true,
1286                                   llvm::GlobalValue::PrivateLinkage,
1287                                   CmdConstant);
1288     GV->setSection(getSectionNameForCommandline(T));
1289     UsedArray.push_back(
1290         ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
1291     if (llvm::GlobalVariable *Old =
1292             M->getGlobalVariable("llvm.cmdline", true)) {
1293       assert(Old->hasOneUse() &&
1294              "llvm.cmdline can only be used once in llvm.compiler.used");
1295       GV->takeName(Old);
1296       Old->eraseFromParent();
1297     } else {
1298       GV->setName("llvm.cmdline");
1299     }
1300   }
1301
1302   if (UsedArray.empty())
1303     return;
1304
1305   // Recreate llvm.compiler.used.
1306   ArrayType *ATy = ArrayType::get(UsedElementType, UsedArray.size());
1307   auto *NewUsed = new GlobalVariable(
1308       *M, ATy, false, llvm::GlobalValue::AppendingLinkage,
1309       llvm::ConstantArray::get(ATy, UsedArray), "llvm.compiler.used");
1310   NewUsed->setSection("llvm.metadata");
1311 }