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/Target/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/ObjCARC.h"
  55 #include "llvm/Transforms/Scalar.h"
  56 #include "llvm/Transforms/Scalar/GVN.h"
  57 #include "llvm/Transforms/Utils/SymbolRewriter.h"
  58 #include <memory>
  59 using namespace clang;
  60 using namespace llvm;
  61
  62 namespace {
  63
  64 // Default filename used for profile generation.
  65 static constexpr StringLiteral DefaultProfileGenName = "default_%m.profraw";
  66
  67 class EmitAssemblyHelper {
  68   DiagnosticsEngine &Diags;
  69   const HeaderSearchOptions &HSOpts;
  70   const CodeGenOptions &CodeGenOpts;
  71   const clang::TargetOptions &TargetOpts;
  72   const LangOptions &LangOpts;
  73   Module *TheModule;
  74
  75   Timer CodeGenerationTime;
  76
  77   std::unique_ptr<raw_pwrite_stream> OS;
  78
  79   TargetIRAnalysis getTargetIRAnalysis() const {
  80     if (TM)
  81       return TM->getTargetIRAnalysis();
  82
  83     return TargetIRAnalysis();
  84   }
  85
  86   void CreatePasses(legacy::PassManager &MPM, legacy::FunctionPassManager &FPM);
  87
  88   /// Generates the TargetMachine.
  89   /// Leaves TM unchanged if it is unable to create the target machine.
  90   /// Some of our clang tests specify triples which are not built
  91   /// into clang. This is okay because these tests check the generated
  92   /// IR, and they require DataLayout which depends on the triple.
  93   /// In this case, we allow this method to fail and not report an error.
  94   /// When MustCreateTM is used, we print an error if we are unable to load
  95   /// the requested target.
  96   void CreateTargetMachine(bool MustCreateTM);
  97
  98   /// Add passes necessary to emit assembly or LLVM IR.
  99   ///
 100   /// \return True on success.
 101   bool AddEmitPasses(legacy::PassManager &CodeGenPasses, BackendAction Action,
 102                      raw_pwrite_stream &OS);
 103
 104 public:
 105   EmitAssemblyHelper(DiagnosticsEngine &_Diags,
 106                      const HeaderSearchOptions &HeaderSearchOpts,
 107                      const CodeGenOptions &CGOpts,
 108                      const clang::TargetOptions &TOpts,
 109                      const LangOptions &LOpts, Module *M)
 110       : Diags(_Diags), HSOpts(HeaderSearchOpts), CodeGenOpts(CGOpts),
 111         TargetOpts(TOpts), LangOpts(LOpts), TheModule(M),
 112         CodeGenerationTime("codegen", "Code Generation Time") {}
 113
 114   ~EmitAssemblyHelper() {
 115     if (CodeGenOpts.DisableFree)
 116       BuryPointer(std::move(TM));
 117   }
 118
 119   std::unique_ptr<TargetMachine> TM;
 120
 121   void EmitAssembly(BackendAction Action,
 122                     std::unique_ptr<raw_pwrite_stream> OS);
 123
 124   void EmitAssemblyWithNewPassManager(BackendAction Action,
 125                                       std::unique_ptr<raw_pwrite_stream> OS);
 126 };
 127
 128 // We need this wrapper to access LangOpts and CGOpts from extension functions
 129 // that we add to the PassManagerBuilder.
 130 class PassManagerBuilderWrapper : public PassManagerBuilder {
 131 public:
 132   PassManagerBuilderWrapper(const Triple &TargetTriple,
 133                             const CodeGenOptions &CGOpts,
 134                             const LangOptions &LangOpts)
 135       : PassManagerBuilder(), TargetTriple(TargetTriple), CGOpts(CGOpts),
 136         LangOpts(LangOpts) {}
 137   const Triple &getTargetTriple() const { return TargetTriple; }
 138   const CodeGenOptions &getCGOpts() const { return CGOpts; }
 139   const LangOptions &getLangOpts() const { return LangOpts; }
 140
 141 private:
 142   const Triple &TargetTriple;
 143   const CodeGenOptions &CGOpts;
 144   const LangOptions &LangOpts;
 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 addAddDiscriminatorsPass(const PassManagerBuilder &Builder,
 164                                      legacy::PassManagerBase &PM) {
 165   PM.add(createAddDiscriminatorsPass());
 166 }
 167
 168 static void addBoundsCheckingPass(const PassManagerBuilder &Builder,
 169                                   legacy::PassManagerBase &PM) {
 170   PM.add(createBoundsCheckingPass());
 171 }
 172
 173 static void addSanitizerCoveragePass(const PassManagerBuilder &Builder,
 174                                      legacy::PassManagerBase &PM) {
 175   const PassManagerBuilderWrapper &BuilderWrapper =
 176       static_cast<const PassManagerBuilderWrapper&>(Builder);
 177   const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
 178   SanitizerCoverageOptions Opts;
 179   Opts.CoverageType =
 180       static_cast<SanitizerCoverageOptions::Type>(CGOpts.SanitizeCoverageType);
 181   Opts.IndirectCalls = CGOpts.SanitizeCoverageIndirectCalls;
 182   Opts.TraceBB = CGOpts.SanitizeCoverageTraceBB;
 183   Opts.TraceCmp = CGOpts.SanitizeCoverageTraceCmp;
 184   Opts.TraceDiv = CGOpts.SanitizeCoverageTraceDiv;
 185   Opts.TraceGep = CGOpts.SanitizeCoverageTraceGep;
 186   Opts.Use8bitCounters = CGOpts.SanitizeCoverage8bitCounters;
 187   Opts.TracePC = CGOpts.SanitizeCoverageTracePC;
 188   Opts.TracePCGuard = CGOpts.SanitizeCoverageTracePCGuard;
 189   Opts.NoPrune = CGOpts.SanitizeCoverageNoPrune;
 190   Opts.Inline8bitCounters = CGOpts.SanitizeCoverageInline8bitCounters;
 191   PM.add(createSanitizerCoverageModulePass(Opts));
 192 }
 193
 194 // Check if ASan should use GC-friendly instrumentation for globals.
 195 // First of all, there is no point if -fdata-sections is off (expect for MachO,
 196 // where this is not a factor). Also, on ELF this feature requires an assembler
 197 // extension that only works with -integrated-as at the moment.
 198 static bool asanUseGlobalsGC(const Triple &T, const CodeGenOptions &CGOpts) {
 199   if (!CGOpts.SanitizeAddressGlobalsDeadStripping)
 200     return false;
 201   switch (T.getObjectFormat()) {
 202   case Triple::MachO:
 203   case Triple::COFF:
 204     return true;
 205   case Triple::ELF:
 206     return CGOpts.DataSections && !CGOpts.DisableIntegratedAS;
 207   default:
 208     return false;
 209   }
 210 }
 211
 212 static void addAddressSanitizerPasses(const PassManagerBuilder &Builder,
 213                                       legacy::PassManagerBase &PM) {
 214   const PassManagerBuilderWrapper &BuilderWrapper =
 215       static_cast<const PassManagerBuilderWrapper&>(Builder);
 216   const Triple &T = BuilderWrapper.getTargetTriple();
 217   const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
 218   bool Recover = CGOpts.SanitizeRecover.has(SanitizerKind::Address);
 219   bool UseAfterScope = CGOpts.SanitizeAddressUseAfterScope;
 220   bool UseGlobalsGC = asanUseGlobalsGC(T, CGOpts);
 221   PM.add(createAddressSanitizerFunctionPass(/*CompileKernel*/ false, Recover,
 222                                             UseAfterScope));
 223   PM.add(createAddressSanitizerModulePass(/*CompileKernel*/ false, Recover,
 224                                           UseGlobalsGC));
 225 }
 226
 227 static void addKernelAddressSanitizerPasses(const PassManagerBuilder &Builder,
 228                                             legacy::PassManagerBase &PM) {
 229   PM.add(createAddressSanitizerFunctionPass(
 230       /*CompileKernel*/ true,
 231       /*Recover*/ true, /*UseAfterScope*/ false));
 232   PM.add(createAddressSanitizerModulePass(/*CompileKernel*/true,
 233                                           /*Recover*/true));
 234 }
 235
 236 static void addMemorySanitizerPass(const PassManagerBuilder &Builder,
 237                                    legacy::PassManagerBase &PM) {
 238   const PassManagerBuilderWrapper &BuilderWrapper =
 239       static_cast<const PassManagerBuilderWrapper&>(Builder);
 240   const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
 241   int TrackOrigins = CGOpts.SanitizeMemoryTrackOrigins;
 242   bool Recover = CGOpts.SanitizeRecover.has(SanitizerKind::Memory);
 243   PM.add(createMemorySanitizerPass(TrackOrigins, Recover));
 244
 245   // MemorySanitizer inserts complex instrumentation that mostly follows
 246   // the logic of the original code, but operates on "shadow" values.
 247   // It can benefit from re-running some general purpose optimization passes.
 248   if (Builder.OptLevel > 0) {
 249     PM.add(createEarlyCSEPass());
 250     PM.add(createReassociatePass());
 251     PM.add(createLICMPass());
 252     PM.add(createGVNPass());
 253     PM.add(createInstructionCombiningPass());
 254     PM.add(createDeadStoreEliminationPass());
 255   }
 256 }
 257
 258 static void addThreadSanitizerPass(const PassManagerBuilder &Builder,
 259                                    legacy::PassManagerBase &PM) {
 260   PM.add(createThreadSanitizerPass());
 261 }
 262
 263 static void addDataFlowSanitizerPass(const PassManagerBuilder &Builder,
 264                                      legacy::PassManagerBase &PM) {
 265   const PassManagerBuilderWrapper &BuilderWrapper =
 266       static_cast<const PassManagerBuilderWrapper&>(Builder);
 267   const LangOptions &LangOpts = BuilderWrapper.getLangOpts();
 268   PM.add(createDataFlowSanitizerPass(LangOpts.SanitizerBlacklistFiles));
 269 }
 270
 271 static void addEfficiencySanitizerPass(const PassManagerBuilder &Builder,
 272                                        legacy::PassManagerBase &PM) {
 273   const PassManagerBuilderWrapper &BuilderWrapper =
 274       static_cast<const PassManagerBuilderWrapper&>(Builder);
 275   const LangOptions &LangOpts = BuilderWrapper.getLangOpts();
 276   EfficiencySanitizerOptions Opts;
 277   if (LangOpts.Sanitize.has(SanitizerKind::EfficiencyCacheFrag))
 278     Opts.ToolType = EfficiencySanitizerOptions::ESAN_CacheFrag;
 279   else if (LangOpts.Sanitize.has(SanitizerKind::EfficiencyWorkingSet))
 280     Opts.ToolType = EfficiencySanitizerOptions::ESAN_WorkingSet;
 281   PM.add(createEfficiencySanitizerPass(Opts));
 282 }
 283
 284 static TargetLibraryInfoImpl *createTLII(llvm::Triple &TargetTriple,
 285                                          const CodeGenOptions &CodeGenOpts) {
 286   TargetLibraryInfoImpl *TLII = new TargetLibraryInfoImpl(TargetTriple);
 287   if (!CodeGenOpts.SimplifyLibCalls)
 288     TLII->disableAllFunctions();
 289   else {
 290     // Disable individual libc/libm calls in TargetLibraryInfo.
 291     LibFunc F;
 292     for (auto &FuncName : CodeGenOpts.getNoBuiltinFuncs())
 293       if (TLII->getLibFunc(FuncName, F))
 294         TLII->setUnavailable(F);
 295   }
 296
 297   switch (CodeGenOpts.getVecLib()) {
 298   case CodeGenOptions::Accelerate:
 299     TLII->addVectorizableFunctionsFromVecLib(TargetLibraryInfoImpl::Accelerate);
 300     break;
 301   case CodeGenOptions::SVML:
 302     TLII->addVectorizableFunctionsFromVecLib(TargetLibraryInfoImpl::SVML);
 303     break;
 304   default:
 305     break;
 306   }
 307   return TLII;
 308 }
 309
 310 static void addSymbolRewriterPass(const CodeGenOptions &Opts,
 311                                   legacy::PassManager *MPM) {
 312   llvm::SymbolRewriter::RewriteDescriptorList DL;
 313
 314   llvm::SymbolRewriter::RewriteMapParser MapParser;
 315   for (const auto &MapFile : Opts.RewriteMapFiles)
 316     MapParser.parse(MapFile, &DL);
 317
 318   MPM->add(createRewriteSymbolsPass(DL));
 319 }
 320
 321 static CodeGenOpt::Level getCGOptLevel(const CodeGenOptions &CodeGenOpts) {
 322   switch (CodeGenOpts.OptimizationLevel) {
 323   default:
 324     llvm_unreachable("Invalid optimization level!");
 325   case 0:
 326     return CodeGenOpt::None;
 327   case 1:
 328     return CodeGenOpt::Less;
 329   case 2:
 330     return CodeGenOpt::Default; // O2/Os/Oz
 331   case 3:
 332     return CodeGenOpt::Aggressive;
 333   }
 334 }
 335
 336 static llvm::CodeModel::Model getCodeModel(const CodeGenOptions &CodeGenOpts) {
 337   unsigned CodeModel =
 338       llvm::StringSwitch<unsigned>(CodeGenOpts.CodeModel)
 339       .Case("small", llvm::CodeModel::Small)
 340       .Case("kernel", llvm::CodeModel::Kernel)
 341       .Case("medium", llvm::CodeModel::Medium)
 342       .Case("large", llvm::CodeModel::Large)
 343       .Case("default", llvm::CodeModel::Default)
 344       .Default(~0u);
 345   assert(CodeModel != ~0u && "invalid code model!");
 346   return static_cast<llvm::CodeModel::Model>(CodeModel);
 347 }
 348
 349 static llvm::Reloc::Model getRelocModel(const CodeGenOptions &CodeGenOpts) {
 350   // Keep this synced with the equivalent code in
 351   // lib/Frontend/CompilerInvocation.cpp
 352   llvm::Optional<llvm::Reloc::Model> RM;
 353   RM = llvm::StringSwitch<llvm::Reloc::Model>(CodeGenOpts.RelocationModel)
 354       .Case("static", llvm::Reloc::Static)
 355       .Case("pic", llvm::Reloc::PIC_)
 356       .Case("ropi", llvm::Reloc::ROPI)
 357       .Case("rwpi", llvm::Reloc::RWPI)
 358       .Case("ropi-rwpi", llvm::Reloc::ROPI_RWPI)
 359       .Case("dynamic-no-pic", llvm::Reloc::DynamicNoPIC);
 360   assert(RM.hasValue() && "invalid PIC model!");
 361   return *RM;
 362 }
 363
 364 static TargetMachine::CodeGenFileType getCodeGenFileType(BackendAction Action) {
 365   if (Action == Backend_EmitObj)
 366     return TargetMachine::CGFT_ObjectFile;
 367   else if (Action == Backend_EmitMCNull)
 368     return TargetMachine::CGFT_Null;
 369   else {
 370     assert(Action == Backend_EmitAssembly && "Invalid action!");
 371     return TargetMachine::CGFT_AssemblyFile;
 372   }
 373 }
 374
 375 static void initTargetOptions(llvm::TargetOptions &Options,
 376                               const CodeGenOptions &CodeGenOpts,
 377                               const clang::TargetOptions &TargetOpts,
 378                               const LangOptions &LangOpts,
 379                               const HeaderSearchOptions &HSOpts) {
 380   Options.ThreadModel =
 381       llvm::StringSwitch<llvm::ThreadModel::Model>(CodeGenOpts.ThreadModel)
 382           .Case("posix", llvm::ThreadModel::POSIX)
 383           .Case("single", llvm::ThreadModel::Single);
 384
 385   // Set float ABI type.
 386   assert((CodeGenOpts.FloatABI == "soft" || CodeGenOpts.FloatABI == "softfp" ||
 387           CodeGenOpts.FloatABI == "hard" || CodeGenOpts.FloatABI.empty()) &&
 388          "Invalid Floating Point ABI!");
 389   Options.FloatABIType =
 390       llvm::StringSwitch<llvm::FloatABI::ABIType>(CodeGenOpts.FloatABI)
 391           .Case("soft", llvm::FloatABI::Soft)
 392           .Case("softfp", llvm::FloatABI::Soft)
 393           .Case("hard", llvm::FloatABI::Hard)
 394           .Default(llvm::FloatABI::Default);
 395
 396   // Set FP fusion mode.
 397   switch (LangOpts.getDefaultFPContractMode()) {
 398   case LangOptions::FPC_Off:
 399     // Preserve any contraction performed by the front-end.  (Strict performs
 400     // splitting of the muladd instrinsic in the backend.)
 401     Options.AllowFPOpFusion = llvm::FPOpFusion::Standard;
 402     break;
 403   case LangOptions::FPC_On:
 404     Options.AllowFPOpFusion = llvm::FPOpFusion::Standard;
 405     break;
 406   case LangOptions::FPC_Fast:
 407     Options.AllowFPOpFusion = llvm::FPOpFusion::Fast;
 408     break;
 409   }
 410
 411   Options.UseInitArray = CodeGenOpts.UseInitArray;
 412   Options.DisableIntegratedAS = CodeGenOpts.DisableIntegratedAS;
 413   Options.CompressDebugSections = CodeGenOpts.CompressDebugSections;
 414   Options.RelaxELFRelocations = CodeGenOpts.RelaxELFRelocations;
 415
 416   // Set EABI version.
 417   Options.EABIVersion = llvm::StringSwitch<llvm::EABI>(TargetOpts.EABIVersion)
 418                             .Case("4", llvm::EABI::EABI4)
 419                             .Case("5", llvm::EABI::EABI5)
 420                             .Case("gnu", llvm::EABI::GNU)
 421                             .Default(llvm::EABI::Default);
 422
 423   if (LangOpts.SjLjExceptions)
 424     Options.ExceptionModel = llvm::ExceptionHandling::SjLj;
 425
 426   Options.NoInfsFPMath = CodeGenOpts.NoInfsFPMath;
 427   Options.NoNaNsFPMath = CodeGenOpts.NoNaNsFPMath;
 428   Options.NoZerosInBSS = CodeGenOpts.NoZeroInitializedInBSS;
 429   Options.UnsafeFPMath = CodeGenOpts.UnsafeFPMath;
 430   Options.StackAlignmentOverride = CodeGenOpts.StackAlignment;
 431   Options.FunctionSections = CodeGenOpts.FunctionSections;
 432   Options.DataSections = CodeGenOpts.DataSections;
 433   Options.UniqueSectionNames = CodeGenOpts.UniqueSectionNames;
 434   Options.EmulatedTLS = CodeGenOpts.EmulatedTLS;
 435   Options.DebuggerTuning = CodeGenOpts.getDebuggerTuning();
 436
 437   if (CodeGenOpts.EnableSplitDwarf)
 438     Options.MCOptions.SplitDwarfFile = CodeGenOpts.SplitDwarfFile;
 439   Options.MCOptions.MCRelaxAll = CodeGenOpts.RelaxAll;
 440   Options.MCOptions.MCSaveTempLabels = CodeGenOpts.SaveTempLabels;
 441   Options.MCOptions.MCUseDwarfDirectory = !CodeGenOpts.NoDwarfDirectoryAsm;
 442   Options.MCOptions.MCNoExecStack = CodeGenOpts.NoExecStack;
 443   Options.MCOptions.MCIncrementalLinkerCompatible =
 444       CodeGenOpts.IncrementalLinkerCompatible;
 445   Options.MCOptions.MCPIECopyRelocations = CodeGenOpts.PIECopyRelocations;
 446   Options.MCOptions.MCFatalWarnings = CodeGenOpts.FatalWarnings;
 447   Options.MCOptions.AsmVerbose = CodeGenOpts.AsmVerbose;
 448   Options.MCOptions.PreserveAsmComments = CodeGenOpts.PreserveAsmComments;
 449   Options.MCOptions.ABIName = TargetOpts.ABI;
 450   for (const auto &Entry : HSOpts.UserEntries)
 451     if (!Entry.IsFramework &&
 452         (Entry.Group == frontend::IncludeDirGroup::Quoted ||
 453          Entry.Group == frontend::IncludeDirGroup::Angled ||
 454          Entry.Group == frontend::IncludeDirGroup::System))
 455       Options.MCOptions.IASSearchPaths.push_back(
 456           Entry.IgnoreSysRoot ? Entry.Path : HSOpts.Sysroot + Entry.Path);
 457 }
 458
 459 void EmitAssemblyHelper::CreatePasses(legacy::PassManager &MPM,
 460                                       legacy::FunctionPassManager &FPM) {
 461   // Handle disabling of all LLVM passes, where we want to preserve the
 462   // internal module before any optimization.
 463   if (CodeGenOpts.DisableLLVMPasses)
 464     return;
 465
 466   // Figure out TargetLibraryInfo.  This needs to be added to MPM and FPM
 467   // manually (and not via PMBuilder), since some passes (eg. InstrProfiling)
 468   // are inserted before PMBuilder ones - they'd get the default-constructed
 469   // TLI with an unknown target otherwise.
 470   Triple TargetTriple(TheModule->getTargetTriple());
 471   std::unique_ptr<TargetLibraryInfoImpl> TLII(
 472       createTLII(TargetTriple, CodeGenOpts));
 473
 474   PassManagerBuilderWrapper PMBuilder(TargetTriple, CodeGenOpts, LangOpts);
 475
 476   // At O0 and O1 we only run the always inliner which is more efficient. At
 477   // higher optimization levels we run the normal inliner.
 478   if (CodeGenOpts.OptimizationLevel <= 1) {
 479     bool InsertLifetimeIntrinsics = (CodeGenOpts.OptimizationLevel != 0 &&
 480                                      !CodeGenOpts.DisableLifetimeMarkers);
 481     PMBuilder.Inliner = createAlwaysInlinerLegacyPass(InsertLifetimeIntrinsics);
 482   } else {
 483     // We do not want to inline hot callsites for SamplePGO module-summary build
 484     // because profile annotation will happen again in ThinLTO backend, and we
 485     // want the IR of the hot path to match the profile.
 486     PMBuilder.Inliner = createFunctionInliningPass(
 487         CodeGenOpts.OptimizationLevel, CodeGenOpts.OptimizeSize,
 488         (!CodeGenOpts.SampleProfileFile.empty() &&
 489          CodeGenOpts.EmitSummaryIndex));
 490   }
 491
 492   PMBuilder.OptLevel = CodeGenOpts.OptimizationLevel;
 493   PMBuilder.SizeLevel = CodeGenOpts.OptimizeSize;
 494   PMBuilder.BBVectorize = CodeGenOpts.VectorizeBB;
 495   PMBuilder.SLPVectorize = CodeGenOpts.VectorizeSLP;
 496   PMBuilder.LoopVectorize = CodeGenOpts.VectorizeLoop;
 497
 498   PMBuilder.DisableUnrollLoops = !CodeGenOpts.UnrollLoops;
 499   PMBuilder.MergeFunctions = CodeGenOpts.MergeFunctions;
 500   PMBuilder.PrepareForThinLTO = CodeGenOpts.EmitSummaryIndex;
 501   PMBuilder.PrepareForLTO = CodeGenOpts.PrepareForLTO;
 502   PMBuilder.RerollLoops = CodeGenOpts.RerollLoops;
 503
 504   MPM.add(new TargetLibraryInfoWrapperPass(*TLII));
 505
 506   if (TM)
 507     TM->adjustPassManager(PMBuilder);
 508
 509   if (CodeGenOpts.DebugInfoForProfiling ||
 510       !CodeGenOpts.SampleProfileFile.empty())
 511     PMBuilder.addExtension(PassManagerBuilder::EP_EarlyAsPossible,
 512                            addAddDiscriminatorsPass);
 513
 514   // In ObjC ARC mode, add the main ARC optimization passes.
 515   if (LangOpts.ObjCAutoRefCount) {
 516     PMBuilder.addExtension(PassManagerBuilder::EP_EarlyAsPossible,
 517                            addObjCARCExpandPass);
 518     PMBuilder.addExtension(PassManagerBuilder::EP_ModuleOptimizerEarly,
 519                            addObjCARCAPElimPass);
 520     PMBuilder.addExtension(PassManagerBuilder::EP_ScalarOptimizerLate,
 521                            addObjCARCOptPass);
 522   }
 523
 524   if (LangOpts.Sanitize.has(SanitizerKind::LocalBounds)) {
 525     PMBuilder.addExtension(PassManagerBuilder::EP_ScalarOptimizerLate,
 526                            addBoundsCheckingPass);
 527     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
 528                            addBoundsCheckingPass);
 529   }
 530
 531   if (CodeGenOpts.SanitizeCoverageType ||
 532       CodeGenOpts.SanitizeCoverageIndirectCalls ||
 533       CodeGenOpts.SanitizeCoverageTraceCmp) {
 534     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
 535                            addSanitizerCoveragePass);
 536     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
 537                            addSanitizerCoveragePass);
 538   }
 539
 540   if (LangOpts.Sanitize.has(SanitizerKind::Address)) {
 541     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
 542                            addAddressSanitizerPasses);
 543     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
 544                            addAddressSanitizerPasses);
 545   }
 546
 547   if (LangOpts.Sanitize.has(SanitizerKind::KernelAddress)) {
 548     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
 549                            addKernelAddressSanitizerPasses);
 550     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
 551                            addKernelAddressSanitizerPasses);
 552   }
 553
 554   if (LangOpts.Sanitize.has(SanitizerKind::Memory)) {
 555     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
 556                            addMemorySanitizerPass);
 557     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
 558                            addMemorySanitizerPass);
 559   }
 560
 561   if (LangOpts.Sanitize.has(SanitizerKind::Thread)) {
 562     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
 563                            addThreadSanitizerPass);
 564     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
 565                            addThreadSanitizerPass);
 566   }
 567
 568   if (LangOpts.Sanitize.has(SanitizerKind::DataFlow)) {
 569     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
 570                            addDataFlowSanitizerPass);
 571     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
 572                            addDataFlowSanitizerPass);
 573   }
 574
 575   if (LangOpts.CoroutinesTS)
 576     addCoroutinePassesToExtensionPoints(PMBuilder);
 577
 578   if (LangOpts.Sanitize.hasOneOf(SanitizerKind::Efficiency)) {
 579     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
 580                            addEfficiencySanitizerPass);
 581     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
 582                            addEfficiencySanitizerPass);
 583   }
 584
 585   // Set up the per-function pass manager.
 586   FPM.add(new TargetLibraryInfoWrapperPass(*TLII));
 587   if (CodeGenOpts.VerifyModule)
 588     FPM.add(createVerifierPass());
 589
 590   // Set up the per-module pass manager.
 591   if (!CodeGenOpts.RewriteMapFiles.empty())
 592     addSymbolRewriterPass(CodeGenOpts, &MPM);
 593
 594   if (!CodeGenOpts.DisableGCov &&
 595       (CodeGenOpts.EmitGcovArcs || CodeGenOpts.EmitGcovNotes)) {
 596     // Not using 'GCOVOptions::getDefault' allows us to avoid exiting if
 597     // LLVM's -default-gcov-version flag is set to something invalid.
 598     GCOVOptions Options;
 599     Options.EmitNotes = CodeGenOpts.EmitGcovNotes;
 600     Options.EmitData = CodeGenOpts.EmitGcovArcs;
 601     memcpy(Options.Version, CodeGenOpts.CoverageVersion, 4);
 602     Options.UseCfgChecksum = CodeGenOpts.CoverageExtraChecksum;
 603     Options.NoRedZone = CodeGenOpts.DisableRedZone;
 604     Options.FunctionNamesInData =
 605         !CodeGenOpts.CoverageNoFunctionNamesInData;
 606     Options.ExitBlockBeforeBody = CodeGenOpts.CoverageExitBlockBeforeBody;
 607     MPM.add(createGCOVProfilerPass(Options));
 608     if (CodeGenOpts.getDebugInfo() == codegenoptions::NoDebugInfo)
 609       MPM.add(createStripSymbolsPass(true));
 610   }
 611
 612   if (CodeGenOpts.hasProfileClangInstr()) {
 613     InstrProfOptions Options;
 614     Options.NoRedZone = CodeGenOpts.DisableRedZone;
 615     Options.InstrProfileOutput = CodeGenOpts.InstrProfileOutput;
 616     MPM.add(createInstrProfilingLegacyPass(Options));
 617   }
 618   if (CodeGenOpts.hasProfileIRInstr()) {
 619     PMBuilder.EnablePGOInstrGen = true;
 620     if (!CodeGenOpts.InstrProfileOutput.empty())
 621       PMBuilder.PGOInstrGen = CodeGenOpts.InstrProfileOutput;
 622     else
 623       PMBuilder.PGOInstrGen = DefaultProfileGenName;
 624   }
 625   if (CodeGenOpts.hasProfileIRUse())
 626     PMBuilder.PGOInstrUse = CodeGenOpts.ProfileInstrumentUsePath;
 627
 628   if (!CodeGenOpts.SampleProfileFile.empty())
 629     PMBuilder.PGOSampleUse = CodeGenOpts.SampleProfileFile;
 630
 631   PMBuilder.populateFunctionPassManager(FPM);
 632   PMBuilder.populateModulePassManager(MPM);
 633 }
 634
 635 static void setCommandLineOpts(const CodeGenOptions &CodeGenOpts) {
 636   SmallVector<const char *, 16> BackendArgs;
 637   BackendArgs.push_back("clang"); // Fake program name.
 638   if (!CodeGenOpts.DebugPass.empty()) {
 639     BackendArgs.push_back("-debug-pass");
 640     BackendArgs.push_back(CodeGenOpts.DebugPass.c_str());
 641   }
 642   if (!CodeGenOpts.LimitFloatPrecision.empty()) {
 643     BackendArgs.push_back("-limit-float-precision");
 644     BackendArgs.push_back(CodeGenOpts.LimitFloatPrecision.c_str());
 645   }
 646   for (const std::string &BackendOption : CodeGenOpts.BackendOptions)
 647     BackendArgs.push_back(BackendOption.c_str());
 648   BackendArgs.push_back(nullptr);
 649   llvm::cl::ParseCommandLineOptions(BackendArgs.size() - 1,
 650                                     BackendArgs.data());
 651 }
 652
 653 void EmitAssemblyHelper::CreateTargetMachine(bool MustCreateTM) {
 654   // Create the TargetMachine for generating code.
 655   std::string Error;
 656   std::string Triple = TheModule->getTargetTriple();
 657   const llvm::Target *TheTarget = TargetRegistry::lookupTarget(Triple, Error);
 658   if (!TheTarget) {
 659     if (MustCreateTM)
 660       Diags.Report(diag::err_fe_unable_to_create_target) << Error;
 661     return;
 662   }
 663
 664   llvm::CodeModel::Model CM  = getCodeModel(CodeGenOpts);
 665   std::string FeaturesStr =
 666       llvm::join(TargetOpts.Features.begin(), TargetOpts.Features.end(), ",");
 667   llvm::Reloc::Model RM = getRelocModel(CodeGenOpts);
 668   CodeGenOpt::Level OptLevel = getCGOptLevel(CodeGenOpts);
 669
 670   llvm::TargetOptions Options;
 671   initTargetOptions(Options, CodeGenOpts, TargetOpts, LangOpts, HSOpts);
 672   TM.reset(TheTarget->createTargetMachine(Triple, TargetOpts.CPU, FeaturesStr,
 673                                           Options, RM, CM, OptLevel));
 674 }
 675
 676 bool EmitAssemblyHelper::AddEmitPasses(legacy::PassManager &CodeGenPasses,
 677                                        BackendAction Action,
 678                                        raw_pwrite_stream &OS) {
 679   // Add LibraryInfo.
 680   llvm::Triple TargetTriple(TheModule->getTargetTriple());
 681   std::unique_ptr<TargetLibraryInfoImpl> TLII(
 682       createTLII(TargetTriple, CodeGenOpts));
 683   CodeGenPasses.add(new TargetLibraryInfoWrapperPass(*TLII));
 684
 685   // Normal mode, emit a .s or .o file by running the code generator. Note,
 686   // this also adds codegenerator level optimization passes.
 687   TargetMachine::CodeGenFileType CGFT = getCodeGenFileType(Action);
 688
 689   // Add ObjC ARC final-cleanup optimizations. This is done as part of the
 690   // "codegen" passes so that it isn't run multiple times when there is
 691   // inlining happening.
 692   if (CodeGenOpts.OptimizationLevel > 0)
 693     CodeGenPasses.add(createObjCARCContractPass());
 694
 695   if (TM->addPassesToEmitFile(CodeGenPasses, OS, CGFT,
 696                               /*DisableVerify=*/!CodeGenOpts.VerifyModule)) {
 697     Diags.Report(diag::err_fe_unable_to_interface_with_target);
 698     return false;
 699   }
 700
 701   return true;
 702 }
 703
 704 void EmitAssemblyHelper::EmitAssembly(BackendAction Action,
 705                                       std::unique_ptr<raw_pwrite_stream> OS) {
 706   TimeRegion Region(llvm::TimePassesIsEnabled ? &CodeGenerationTime : nullptr);
 707
 708   setCommandLineOpts(CodeGenOpts);
 709
 710   bool UsesCodeGen = (Action != Backend_EmitNothing &&
 711                       Action != Backend_EmitBC &&
 712                       Action != Backend_EmitLL);
 713   CreateTargetMachine(UsesCodeGen);
 714
 715   if (UsesCodeGen && !TM)
 716     return;
 717   if (TM)
 718     TheModule->setDataLayout(TM->createDataLayout());
 719
 720   legacy::PassManager PerModulePasses;
 721   PerModulePasses.add(
 722       createTargetTransformInfoWrapperPass(getTargetIRAnalysis()));
 723
 724   legacy::FunctionPassManager PerFunctionPasses(TheModule);
 725   PerFunctionPasses.add(
 726       createTargetTransformInfoWrapperPass(getTargetIRAnalysis()));
 727
 728   CreatePasses(PerModulePasses, PerFunctionPasses);
 729
 730   legacy::PassManager CodeGenPasses;
 731   CodeGenPasses.add(
 732       createTargetTransformInfoWrapperPass(getTargetIRAnalysis()));
 733
 734   std::unique_ptr<raw_fd_ostream> ThinLinkOS;
 735
 736   switch (Action) {
 737   case Backend_EmitNothing:
 738     break;
 739
 740   case Backend_EmitBC:
 741     if (CodeGenOpts.EmitSummaryIndex) {
 742       if (!CodeGenOpts.ThinLinkBitcodeFile.empty()) {
 743         std::error_code EC;
 744         ThinLinkOS.reset(new llvm::raw_fd_ostream(
 745             CodeGenOpts.ThinLinkBitcodeFile, EC,
 746             llvm::sys::fs::F_None));
 747         if (EC) {
 748           Diags.Report(diag::err_fe_unable_to_open_output) << CodeGenOpts.ThinLinkBitcodeFile
 749                                                            << EC.message();
 750           return;
 751         }
 752       }
 753       PerModulePasses.add(
 754           createWriteThinLTOBitcodePass(*OS, ThinLinkOS.get()));
 755     }
 756     else
 757       PerModulePasses.add(
 758           createBitcodeWriterPass(*OS, CodeGenOpts.EmitLLVMUseLists));
 759     break;
 760
 761   case Backend_EmitLL:
 762     PerModulePasses.add(
 763         createPrintModulePass(*OS, "", CodeGenOpts.EmitLLVMUseLists));
 764     break;
 765
 766   default:
 767     if (!AddEmitPasses(CodeGenPasses, Action, *OS))
 768       return;
 769   }
 770
 771   // Before executing passes, print the final values of the LLVM options.
 772   cl::PrintOptionValues();
 773
 774   // Run passes. For now we do all passes at once, but eventually we
 775   // would like to have the option of streaming code generation.
 776
 777   {
 778     PrettyStackTraceString CrashInfo("Per-function optimization");
 779
 780     PerFunctionPasses.doInitialization();
 781     for (Function &F : *TheModule)
 782       if (!F.isDeclaration())
 783         PerFunctionPasses.run(F);
 784     PerFunctionPasses.doFinalization();
 785   }
 786
 787   {
 788     PrettyStackTraceString CrashInfo("Per-module optimization passes");
 789     PerModulePasses.run(*TheModule);
 790   }
 791
 792   {
 793     PrettyStackTraceString CrashInfo("Code generation");
 794     CodeGenPasses.run(*TheModule);
 795   }
 796 }
 797
 798 static PassBuilder::OptimizationLevel mapToLevel(const CodeGenOptions &Opts) {
 799   switch (Opts.OptimizationLevel) {
 800   default:
 801     llvm_unreachable("Invalid optimization level!");
 802
 803   case 1:
 804     return PassBuilder::O1;
 805
 806   case 2:
 807     switch (Opts.OptimizeSize) {
 808     default:
 809       llvm_unreachable("Invalide optimization level for size!");
 810
 811     case 0:
 812       return PassBuilder::O2;
 813
 814     case 1:
 815       return PassBuilder::Os;
 816
 817     case 2:
 818       return PassBuilder::Oz;
 819     }
 820
 821   case 3:
 822     return PassBuilder::O3;
 823   }
 824 }
 825
 826 /// A clean version of `EmitAssembly` that uses the new pass manager.
 827 ///
 828 /// Not all features are currently supported in this system, but where
 829 /// necessary it falls back to the legacy pass manager to at least provide
 830 /// basic functionality.
 831 ///
 832 /// This API is planned to have its functionality finished and then to replace
 833 /// `EmitAssembly` at some point in the future when the default switches.
 834 void EmitAssemblyHelper::EmitAssemblyWithNewPassManager(
 835     BackendAction Action, std::unique_ptr<raw_pwrite_stream> OS) {
 836   TimeRegion Region(llvm::TimePassesIsEnabled ? &CodeGenerationTime : nullptr);
 837   setCommandLineOpts(CodeGenOpts);
 838
 839   // The new pass manager always makes a target machine available to passes
 840   // during construction.
 841   CreateTargetMachine(/*MustCreateTM*/ true);
 842   if (!TM)
 843     // This will already be diagnosed, just bail.
 844     return;
 845   TheModule->setDataLayout(TM->createDataLayout());
 846
 847   PGOOptions PGOOpt;
 848
 849   // -fprofile-generate.
 850   PGOOpt.RunProfileGen = CodeGenOpts.hasProfileIRInstr();
 851   if (PGOOpt.RunProfileGen)
 852     PGOOpt.ProfileGenFile = CodeGenOpts.InstrProfileOutput.empty() ?
 853       DefaultProfileGenName : CodeGenOpts.InstrProfileOutput;
 854
 855   // -fprofile-use.
 856   if (CodeGenOpts.hasProfileIRUse())
 857     PGOOpt.ProfileUseFile = CodeGenOpts.ProfileInstrumentUsePath;
 858
 859   // Only pass a PGO options struct if -fprofile-generate or
 860   // -fprofile-use were passed on the cmdline.
 861   PassBuilder PB(TM.get(),
 862     (PGOOpt.RunProfileGen ||
 863       !PGOOpt.ProfileUseFile.empty()) ?
 864         Optional<PGOOptions>(PGOOpt) : None);
 865
 866   LoopAnalysisManager LAM;
 867   FunctionAnalysisManager FAM;
 868   CGSCCAnalysisManager CGAM;
 869   ModuleAnalysisManager MAM;
 870
 871   // Register the AA manager first so that our version is the one used.
 872   FAM.registerPass([&] { return PB.buildDefaultAAPipeline(); });
 873
 874   // Register all the basic analyses with the managers.
 875   PB.registerModuleAnalyses(MAM);
 876   PB.registerCGSCCAnalyses(CGAM);
 877   PB.registerFunctionAnalyses(FAM);
 878   PB.registerLoopAnalyses(LAM);
 879   PB.crossRegisterProxies(LAM, FAM, CGAM, MAM);
 880
 881   ModulePassManager MPM;
 882
 883   if (!CodeGenOpts.DisableLLVMPasses) {
 884     if (CodeGenOpts.OptimizationLevel == 0) {
 885       // Build a minimal pipeline based on the semantics required by Clang,
 886       // which is just that always inlining occurs.
 887       MPM.addPass(AlwaysInlinerPass());
 888     } else {
 889       // Otherwise, use the default pass pipeline. We also have to map our
 890       // optimization levels into one of the distinct levels used to configure
 891       // the pipeline.
 892       PassBuilder::OptimizationLevel Level = mapToLevel(CodeGenOpts);
 893
 894       MPM = PB.buildPerModuleDefaultPipeline(Level);
 895     }
 896   }
 897
 898   // FIXME: We still use the legacy pass manager to do code generation. We
 899   // create that pass manager here and use it as needed below.
 900   legacy::PassManager CodeGenPasses;
 901   bool NeedCodeGen = false;
 902   Optional<raw_fd_ostream> ThinLinkOS;
 903
 904   // Append any output we need to the pass manager.
 905   switch (Action) {
 906   case Backend_EmitNothing:
 907     break;
 908
 909   case Backend_EmitBC:
 910     if (CodeGenOpts.EmitSummaryIndex) {
 911       if (!CodeGenOpts.ThinLinkBitcodeFile.empty()) {
 912         std::error_code EC;
 913         ThinLinkOS.emplace(CodeGenOpts.ThinLinkBitcodeFile, EC,
 914                            llvm::sys::fs::F_None);
 915         if (EC) {
 916           Diags.Report(diag::err_fe_unable_to_open_output)
 917               << CodeGenOpts.ThinLinkBitcodeFile << EC.message();
 918           return;
 919         }
 920       }
 921       MPM.addPass(
 922           ThinLTOBitcodeWriterPass(*OS, ThinLinkOS ? &*ThinLinkOS : nullptr));
 923     } else {
 924       MPM.addPass(BitcodeWriterPass(*OS, CodeGenOpts.EmitLLVMUseLists,
 925                                     CodeGenOpts.EmitSummaryIndex,
 926                                     CodeGenOpts.EmitSummaryIndex));
 927     }
 928     break;
 929
 930   case Backend_EmitLL:
 931     MPM.addPass(PrintModulePass(*OS, "", CodeGenOpts.EmitLLVMUseLists));
 932     break;
 933
 934   case Backend_EmitAssembly:
 935   case Backend_EmitMCNull:
 936   case Backend_EmitObj:
 937     NeedCodeGen = true;
 938     CodeGenPasses.add(
 939         createTargetTransformInfoWrapperPass(getTargetIRAnalysis()));
 940     if (!AddEmitPasses(CodeGenPasses, Action, *OS))
 941       // FIXME: Should we handle this error differently?
 942       return;
 943     break;
 944   }
 945
 946   // Before executing passes, print the final values of the LLVM options.
 947   cl::PrintOptionValues();
 948
 949   // Now that we have all of the passes ready, run them.
 950   {
 951     PrettyStackTraceString CrashInfo("Optimizer");
 952     MPM.run(*TheModule, MAM);
 953   }
 954
 955   // Now if needed, run the legacy PM for codegen.
 956   if (NeedCodeGen) {
 957     PrettyStackTraceString CrashInfo("Code generation");
 958     CodeGenPasses.run(*TheModule);
 959   }
 960 }
 961
 962 Expected<BitcodeModule> clang::FindThinLTOModule(MemoryBufferRef MBRef) {
 963   Expected<std::vector<BitcodeModule>> BMsOrErr = getBitcodeModuleList(MBRef);
 964   if (!BMsOrErr)
 965     return BMsOrErr.takeError();
 966
 967   // The bitcode file may contain multiple modules, we want the one with a
 968   // summary.
 969   for (BitcodeModule &BM : *BMsOrErr) {
 970     Expected<bool> HasSummary = BM.hasSummary();
 971     if (HasSummary && *HasSummary)
 972       return BM;
 973   }
 974
 975   return make_error<StringError>("Could not find module summary",
 976                                  inconvertibleErrorCode());
 977 }
 978
 979 static void runThinLTOBackend(ModuleSummaryIndex *CombinedIndex, Module *M,
 980                               const HeaderSearchOptions &HeaderOpts,
 981                               const CodeGenOptions &CGOpts,
 982                               const clang::TargetOptions &TOpts,
 983                               const LangOptions &LOpts,
 984                               std::unique_ptr<raw_pwrite_stream> OS,
 985                               std::string SampleProfile,
 986                               BackendAction Action) {
 987   StringMap<std::map<GlobalValue::GUID, GlobalValueSummary *>>
 988       ModuleToDefinedGVSummaries;
 989   CombinedIndex->collectDefinedGVSummariesPerModule(ModuleToDefinedGVSummaries);
 990
 991   setCommandLineOpts(CGOpts);
 992
 993   // We can simply import the values mentioned in the combined index, since
 994   // we should only invoke this using the individual indexes written out
 995   // via a WriteIndexesThinBackend.
 996   FunctionImporter::ImportMapTy ImportList;
 997   for (auto &GlobalList : *CombinedIndex) {
 998     // Ignore entries for undefined references.
 999     if (GlobalList.second.SummaryList.empty())
1000       continue;
1001
1002     auto GUID = GlobalList.first;
1003     assert(GlobalList.second.SummaryList.size() == 1 &&
1004            "Expected individual combined index to have one summary per GUID");
1005     auto &Summary = GlobalList.second.SummaryList[0];
1006     // Skip the summaries for the importing module. These are included to
1007     // e.g. record required linkage changes.
1008     if (Summary->modulePath() == M->getModuleIdentifier())
1009       continue;
1010     // Doesn't matter what value we plug in to the map, just needs an entry
1011     // to provoke importing by thinBackend.
1012     ImportList[Summary->modulePath()][GUID] = 1;
1013   }
1014
1015   std::vector<std::unique_ptr<llvm::MemoryBuffer>> OwnedImports;
1016   MapVector<llvm::StringRef, llvm::BitcodeModule> ModuleMap;
1017
1018   for (auto &I : ImportList) {
1019     ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> MBOrErr =
1020         llvm::MemoryBuffer::getFile(I.first());
1021     if (!MBOrErr) {
1022       errs() << "Error loading imported file '" << I.first()
1023              << "': " << MBOrErr.getError().message() << "\n";
1024       return;
1025     }
1026
1027     Expected<BitcodeModule> BMOrErr = FindThinLTOModule(**MBOrErr);
1028     if (!BMOrErr) {
1029       handleAllErrors(BMOrErr.takeError(), [&](ErrorInfoBase &EIB) {
1030         errs() << "Error loading imported file '" << I.first()
1031                << "': " << EIB.message() << '\n';
1032       });
1033       return;
1034     }
1035     ModuleMap.insert({I.first(), *BMOrErr});
1036
1037     OwnedImports.push_back(std::move(*MBOrErr));
1038   }
1039   auto AddStream = [&](size_t Task) {
1040     return llvm::make_unique<lto::NativeObjectStream>(std::move(OS));
1041   };
1042   lto::Config Conf;
1043   Conf.CPU = TOpts.CPU;
1044   Conf.CodeModel = getCodeModel(CGOpts);
1045   Conf.MAttrs = TOpts.Features;
1046   Conf.RelocModel = getRelocModel(CGOpts);
1047   Conf.CGOptLevel = getCGOptLevel(CGOpts);
1048   initTargetOptions(Conf.Options, CGOpts, TOpts, LOpts, HeaderOpts);
1049   Conf.SampleProfile = std::move(SampleProfile);
1050   Conf.UseNewPM = CGOpts.ExperimentalNewPassManager;
1051   switch (Action) {
1052   case Backend_EmitNothing:
1053     Conf.PreCodeGenModuleHook = [](size_t Task, const Module &Mod) {
1054       return false;
1055     };
1056     break;
1057   case Backend_EmitLL:
1058     Conf.PreCodeGenModuleHook = [&](size_t Task, const Module &Mod) {
1059       M->print(*OS, nullptr, CGOpts.EmitLLVMUseLists);
1060       return false;
1061     };
1062     break;
1063   case Backend_EmitBC:
1064     Conf.PreCodeGenModuleHook = [&](size_t Task, const Module &Mod) {
1065       WriteBitcodeToFile(M, *OS, CGOpts.EmitLLVMUseLists);
1066       return false;
1067     };
1068     break;
1069   default:
1070     Conf.CGFileType = getCodeGenFileType(Action);
1071     break;
1072   }
1073   if (Error E = thinBackend(
1074           Conf, 0, AddStream, *M, *CombinedIndex, ImportList,
1075           ModuleToDefinedGVSummaries[M->getModuleIdentifier()], ModuleMap)) {
1076     handleAllErrors(std::move(E), [&](ErrorInfoBase &EIB) {
1077       errs() << "Error running ThinLTO backend: " << EIB.message() << '\n';
1078     });
1079   }
1080 }
1081
1082 void clang::EmitBackendOutput(DiagnosticsEngine &Diags,
1083                               const HeaderSearchOptions &HeaderOpts,
1084                               const CodeGenOptions &CGOpts,
1085                               const clang::TargetOptions &TOpts,
1086                               const LangOptions &LOpts,
1087                               const llvm::DataLayout &TDesc, Module *M,
1088                               BackendAction Action,
1089                               std::unique_ptr<raw_pwrite_stream> OS) {
1090   if (!CGOpts.ThinLTOIndexFile.empty()) {
1091     // If we are performing a ThinLTO importing compile, load the function index
1092     // into memory and pass it into runThinLTOBackend, which will run the
1093     // function importer and invoke LTO passes.
1094     Expected<std::unique_ptr<ModuleSummaryIndex>> IndexOrErr =
1095         llvm::getModuleSummaryIndexForFile(CGOpts.ThinLTOIndexFile,
1096                                            /*IgnoreEmptyThinLTOIndexFile*/true);
1097     if (!IndexOrErr) {
1098       logAllUnhandledErrors(IndexOrErr.takeError(), errs(),
1099                             "Error loading index file '" +
1100                             CGOpts.ThinLTOIndexFile + "': ");
1101       return;
1102     }
1103     std::unique_ptr<ModuleSummaryIndex> CombinedIndex = std::move(*IndexOrErr);
1104     // A null CombinedIndex means we should skip ThinLTO compilation
1105     // (LLVM will optionally ignore empty index files, returning null instead
1106     // of an error).
1107     bool DoThinLTOBackend = CombinedIndex != nullptr;
1108     if (DoThinLTOBackend) {
1109       runThinLTOBackend(CombinedIndex.get(), M, HeaderOpts, CGOpts, TOpts,
1110                         LOpts, std::move(OS), CGOpts.SampleProfileFile, Action);
1111       return;
1112     }
1113   }
1114
1115   EmitAssemblyHelper AsmHelper(Diags, HeaderOpts, CGOpts, TOpts, LOpts, M);
1116
1117   if (CGOpts.ExperimentalNewPassManager)
1118     AsmHelper.EmitAssemblyWithNewPassManager(Action, std::move(OS));
1119   else
1120     AsmHelper.EmitAssembly(Action, std::move(OS));
1121
1122   // Verify clang's TargetInfo DataLayout against the LLVM TargetMachine's
1123   // DataLayout.
1124   if (AsmHelper.TM) {
1125     std::string DLDesc = M->getDataLayout().getStringRepresentation();
1126     if (DLDesc != TDesc.getStringRepresentation()) {
1127       unsigned DiagID = Diags.getCustomDiagID(
1128           DiagnosticsEngine::Error, "backend data layout '%0' does not match "
1129                                     "expected target description '%1'");
1130       Diags.Report(DiagID) << DLDesc << TDesc.getStringRepresentation();
1131     }
1132   }
1133 }
1134
1135 static const char* getSectionNameForBitcode(const Triple &T) {
1136   switch (T.getObjectFormat()) {
1137   case Triple::MachO:
1138     return "__LLVM,__bitcode";
1139   case Triple::COFF:
1140   case Triple::ELF:
1141   case Triple::Wasm:
1142   case Triple::UnknownObjectFormat:
1143     return ".llvmbc";
1144   }
1145   llvm_unreachable("Unimplemented ObjectFormatType");
1146 }
1147
1148 static const char* getSectionNameForCommandline(const Triple &T) {
1149   switch (T.getObjectFormat()) {
1150   case Triple::MachO:
1151     return "__LLVM,__cmdline";
1152   case Triple::COFF:
1153   case Triple::ELF:
1154   case Triple::Wasm:
1155   case Triple::UnknownObjectFormat:
1156     return ".llvmcmd";
1157   }
1158   llvm_unreachable("Unimplemented ObjectFormatType");
1159 }
1160
1161 // With -fembed-bitcode, save a copy of the llvm IR as data in the
1162 // __LLVM,__bitcode section.
1163 void clang::EmbedBitcode(llvm::Module *M, const CodeGenOptions &CGOpts,
1164                          llvm::MemoryBufferRef Buf) {
1165   if (CGOpts.getEmbedBitcode() == CodeGenOptions::Embed_Off)
1166     return;
1167
1168   // Save llvm.compiler.used and remote it.
1169   SmallVector<Constant*, 2> UsedArray;
1170   SmallSet<GlobalValue*, 4> UsedGlobals;
1171   Type *UsedElementType = Type::getInt8Ty(M->getContext())->getPointerTo(0);
1172   GlobalVariable *Used = collectUsedGlobalVariables(*M, UsedGlobals, true);
1173   for (auto *GV : UsedGlobals) {
1174     if (GV->getName() != "llvm.embedded.module" &&
1175         GV->getName() != "llvm.cmdline")
1176       UsedArray.push_back(
1177           ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
1178   }
1179   if (Used)
1180     Used->eraseFromParent();
1181
1182   // Embed the bitcode for the llvm module.
1183   std::string Data;
1184   ArrayRef<uint8_t> ModuleData;
1185   Triple T(M->getTargetTriple());
1186   // Create a constant that contains the bitcode.
1187   // In case of embedding a marker, ignore the input Buf and use the empty
1188   // ArrayRef. It is also legal to create a bitcode marker even Buf is empty.
1189   if (CGOpts.getEmbedBitcode() != CodeGenOptions::Embed_Marker) {
1190     if (!isBitcode((const unsigned char *)Buf.getBufferStart(),
1191                    (const unsigned char *)Buf.getBufferEnd())) {
1192       // If the input is LLVM Assembly, bitcode is produced by serializing
1193       // the module. Use-lists order need to be perserved in this case.
1194       llvm::raw_string_ostream OS(Data);
1195       llvm::WriteBitcodeToFile(M, OS, /* ShouldPreserveUseListOrder */ true);
1196       ModuleData =
1197           ArrayRef<uint8_t>((const uint8_t *)OS.str().data(), OS.str().size());
1198     } else
1199       // If the input is LLVM bitcode, write the input byte stream directly.
1200       ModuleData = ArrayRef<uint8_t>((const uint8_t *)Buf.getBufferStart(),
1201                                      Buf.getBufferSize());
1202   }
1203   llvm::Constant *ModuleConstant =
1204       llvm::ConstantDataArray::get(M->getContext(), ModuleData);
1205   llvm::GlobalVariable *GV = new llvm::GlobalVariable(
1206       *M, ModuleConstant->getType(), true, llvm::GlobalValue::PrivateLinkage,
1207       ModuleConstant);
1208   GV->setSection(getSectionNameForBitcode(T));
1209   UsedArray.push_back(
1210       ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
1211   if (llvm::GlobalVariable *Old =
1212           M->getGlobalVariable("llvm.embedded.module", true)) {
1213     assert(Old->hasOneUse() &&
1214            "llvm.embedded.module can only be used once in llvm.compiler.used");
1215     GV->takeName(Old);
1216     Old->eraseFromParent();
1217   } else {
1218     GV->setName("llvm.embedded.module");
1219   }
1220
1221   // Skip if only bitcode needs to be embedded.
1222   if (CGOpts.getEmbedBitcode() != CodeGenOptions::Embed_Bitcode) {
1223     // Embed command-line options.
1224     ArrayRef<uint8_t> CmdData(const_cast<uint8_t *>(CGOpts.CmdArgs.data()),
1225                               CGOpts.CmdArgs.size());
1226     llvm::Constant *CmdConstant =
1227       llvm::ConstantDataArray::get(M->getContext(), CmdData);
1228     GV = new llvm::GlobalVariable(*M, CmdConstant->getType(), true,
1229                                   llvm::GlobalValue::PrivateLinkage,
1230                                   CmdConstant);
1231     GV->setSection(getSectionNameForCommandline(T));
1232     UsedArray.push_back(
1233         ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
1234     if (llvm::GlobalVariable *Old =
1235             M->getGlobalVariable("llvm.cmdline", true)) {
1236       assert(Old->hasOneUse() &&
1237              "llvm.cmdline can only be used once in llvm.compiler.used");
1238       GV->takeName(Old);
1239       Old->eraseFromParent();
1240     } else {
1241       GV->setName("llvm.cmdline");
1242     }
1243   }
1244
1245   if (UsedArray.empty())
1246     return;
1247
1248   // Recreate llvm.compiler.used.
1249   ArrayType *ATy = ArrayType::get(UsedElementType, UsedArray.size());
1250   auto *NewUsed = new GlobalVariable(
1251       *M, ATy, false, llvm::GlobalValue::AppendingLinkage,
1252       llvm::ConstantArray::get(ATy, UsedArray), "llvm.compiler.used");
1253   NewUsed->setSection("llvm.metadata");
1254 }