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

   1 //===--- BackendUtil.cpp - LLVM Backend Utilities -------------------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9
  10 #include "clang/CodeGen/BackendUtil.h"
  11 #include "clang/Basic/Diagnostic.h"
  12 #include "clang/Basic/LangOptions.h"
  13 #include "clang/Basic/TargetOptions.h"
  14 #include "clang/Frontend/CodeGenOptions.h"
  15 #include "clang/Frontend/FrontendDiagnostic.h"
  16 #include "clang/Frontend/Utils.h"
  17 #include "llvm/ADT/StringExtras.h"
  18 #include "llvm/ADT/StringSwitch.h"
  19 #include "llvm/ADT/Triple.h"
  20 #include "llvm/Analysis/TargetLibraryInfo.h"
  21 #include "llvm/Analysis/TargetTransformInfo.h"
  22 #include "llvm/Bitcode/BitcodeWriterPass.h"
  23 #include "llvm/Bitcode/ReaderWriter.h"
  24 #include "llvm/CodeGen/RegAllocRegistry.h"
  25 #include "llvm/CodeGen/SchedulerRegistry.h"
  26 #include "llvm/IR/DataLayout.h"
  27 #include "llvm/IR/ModuleSummaryIndex.h"
  28 #include "llvm/IR/IRPrintingPasses.h"
  29 #include "llvm/IR/LegacyPassManager.h"
  30 #include "llvm/IR/Module.h"
  31 #include "llvm/IR/Verifier.h"
  32 #include "llvm/MC/SubtargetFeature.h"
  33 #include "llvm/Object/ModuleSummaryIndexObjectFile.h"
  34 #include "llvm/Support/CommandLine.h"
  35 #include "llvm/Support/PrettyStackTrace.h"
  36 #include "llvm/Support/TargetRegistry.h"
  37 #include "llvm/Support/Timer.h"
  38 #include "llvm/Support/raw_ostream.h"
  39 #include "llvm/Target/TargetMachine.h"
  40 #include "llvm/Target/TargetOptions.h"
  41 #include "llvm/Target/TargetSubtargetInfo.h"
  42 #include "llvm/Transforms/IPO.h"
  43 #include "llvm/Transforms/IPO/PassManagerBuilder.h"
  44 #include "llvm/Transforms/Instrumentation.h"
  45 #include "llvm/Transforms/ObjCARC.h"
  46 #include "llvm/Transforms/Scalar.h"
  47 #include "llvm/Transforms/Scalar/GVN.h"
  48 #include "llvm/Transforms/Utils/SymbolRewriter.h"
  49 #include <memory>
  50 using namespace clang;
  51 using namespace llvm;
  52
  53 namespace {
  54
  55 class EmitAssemblyHelper {
  56   DiagnosticsEngine &Diags;
  57   const CodeGenOptions &CodeGenOpts;
  58   const clang::TargetOptions &TargetOpts;
  59   const LangOptions &LangOpts;
  60   Module *TheModule;
  61
  62   Timer CodeGenerationTime;
  63
  64   std::unique_ptr<raw_pwrite_stream> OS;
  65
  66 private:
  67   TargetIRAnalysis getTargetIRAnalysis() const {
  68     if (TM)
  69       return TM->getTargetIRAnalysis();
  70
  71     return TargetIRAnalysis();
  72   }
  73
  74   /// Set LLVM command line options passed through -backend-option.
  75   void setCommandLineOpts();
  76
  77   void CreatePasses(legacy::PassManager &MPM, legacy::FunctionPassManager &FPM,
  78                     ModuleSummaryIndex *ModuleSummary);
  79
  80   /// Generates the TargetMachine.
  81   /// Leaves TM unchanged if it is unable to create the target machine.
  82   /// Some of our clang tests specify triples which are not built
  83   /// into clang. This is okay because these tests check the generated
  84   /// IR, and they require DataLayout which depends on the triple.
  85   /// In this case, we allow this method to fail and not report an error.
  86   /// When MustCreateTM is used, we print an error if we are unable to load
  87   /// the requested target.
  88   void CreateTargetMachine(bool MustCreateTM);
  89
  90   /// Add passes necessary to emit assembly or LLVM IR.
  91   ///
  92   /// \return True on success.
  93   bool AddEmitPasses(legacy::PassManager &CodeGenPasses, BackendAction Action,
  94                      raw_pwrite_stream &OS);
  95
  96 public:
  97   EmitAssemblyHelper(DiagnosticsEngine &_Diags, const CodeGenOptions &CGOpts,
  98                      const clang::TargetOptions &TOpts,
  99                      const LangOptions &LOpts, Module *M)
 100       : Diags(_Diags), CodeGenOpts(CGOpts), TargetOpts(TOpts), LangOpts(LOpts),
 101         TheModule(M), CodeGenerationTime("Code Generation Time") {}
 102
 103   ~EmitAssemblyHelper() {
 104     if (CodeGenOpts.DisableFree)
 105       BuryPointer(std::move(TM));
 106   }
 107
 108   std::unique_ptr<TargetMachine> TM;
 109
 110   void EmitAssembly(BackendAction Action,
 111                     std::unique_ptr<raw_pwrite_stream> OS);
 112 };
 113
 114 // We need this wrapper to access LangOpts and CGOpts from extension functions
 115 // that we add to the PassManagerBuilder.
 116 class PassManagerBuilderWrapper : public PassManagerBuilder {
 117 public:
 118   PassManagerBuilderWrapper(const CodeGenOptions &CGOpts,
 119                             const LangOptions &LangOpts)
 120       : PassManagerBuilder(), CGOpts(CGOpts), LangOpts(LangOpts) {}
 121   const CodeGenOptions &getCGOpts() const { return CGOpts; }
 122   const LangOptions &getLangOpts() const { return LangOpts; }
 123 private:
 124   const CodeGenOptions &CGOpts;
 125   const LangOptions &LangOpts;
 126 };
 127
 128 }
 129
 130 static void addObjCARCAPElimPass(const PassManagerBuilder &Builder, PassManagerBase &PM) {
 131   if (Builder.OptLevel > 0)
 132     PM.add(createObjCARCAPElimPass());
 133 }
 134
 135 static void addObjCARCExpandPass(const PassManagerBuilder &Builder, PassManagerBase &PM) {
 136   if (Builder.OptLevel > 0)
 137     PM.add(createObjCARCExpandPass());
 138 }
 139
 140 static void addObjCARCOptPass(const PassManagerBuilder &Builder, PassManagerBase &PM) {
 141   if (Builder.OptLevel > 0)
 142     PM.add(createObjCARCOptPass());
 143 }
 144
 145 static void addAddDiscriminatorsPass(const PassManagerBuilder &Builder,
 146                                      legacy::PassManagerBase &PM) {
 147   PM.add(createAddDiscriminatorsPass());
 148 }
 149
 150 static void addCleanupPassesForSampleProfiler(
 151     const PassManagerBuilder &Builder, legacy::PassManagerBase &PM) {
 152   // instcombine is needed before sample profile annotation because it converts
 153   // certain function calls to be inlinable. simplifycfg and sroa are needed
 154   // before instcombine for necessary preparation. E.g. load store is eliminated
 155   // properly so that instcombine will not introduce unecessary liverange.
 156   PM.add(createCFGSimplificationPass());
 157   PM.add(createSROAPass());
 158   PM.add(createInstructionCombiningPass());
 159 }
 160
 161 static void addBoundsCheckingPass(const PassManagerBuilder &Builder,
 162                                   legacy::PassManagerBase &PM) {
 163   PM.add(createBoundsCheckingPass());
 164 }
 165
 166 static void addSanitizerCoveragePass(const PassManagerBuilder &Builder,
 167                                      legacy::PassManagerBase &PM) {
 168   const PassManagerBuilderWrapper &BuilderWrapper =
 169       static_cast<const PassManagerBuilderWrapper&>(Builder);
 170   const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
 171   SanitizerCoverageOptions Opts;
 172   Opts.CoverageType =
 173       static_cast<SanitizerCoverageOptions::Type>(CGOpts.SanitizeCoverageType);
 174   Opts.IndirectCalls = CGOpts.SanitizeCoverageIndirectCalls;
 175   Opts.TraceBB = CGOpts.SanitizeCoverageTraceBB;
 176   Opts.TraceCmp = CGOpts.SanitizeCoverageTraceCmp;
 177   Opts.Use8bitCounters = CGOpts.SanitizeCoverage8bitCounters;
 178   Opts.TracePC = CGOpts.SanitizeCoverageTracePC;
 179   PM.add(createSanitizerCoverageModulePass(Opts));
 180 }
 181
 182 static void addAddressSanitizerPasses(const PassManagerBuilder &Builder,
 183                                       legacy::PassManagerBase &PM) {
 184   const PassManagerBuilderWrapper &BuilderWrapper =
 185       static_cast<const PassManagerBuilderWrapper&>(Builder);
 186   const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
 187   bool Recover = CGOpts.SanitizeRecover.has(SanitizerKind::Address);
 188   bool UseAfterScope = CGOpts.SanitizeAddressUseAfterScope;
 189   PM.add(createAddressSanitizerFunctionPass(/*CompileKernel*/ false, Recover,
 190                                             UseAfterScope));
 191   PM.add(createAddressSanitizerModulePass(/*CompileKernel*/false, Recover));
 192 }
 193
 194 static void addKernelAddressSanitizerPasses(const PassManagerBuilder &Builder,
 195                                             legacy::PassManagerBase &PM) {
 196   PM.add(createAddressSanitizerFunctionPass(
 197       /*CompileKernel*/ true,
 198       /*Recover*/ true, /*UseAfterScope*/ false));
 199   PM.add(createAddressSanitizerModulePass(/*CompileKernel*/true,
 200                                           /*Recover*/true));
 201 }
 202
 203 static void addMemorySanitizerPass(const PassManagerBuilder &Builder,
 204                                    legacy::PassManagerBase &PM) {
 205   const PassManagerBuilderWrapper &BuilderWrapper =
 206       static_cast<const PassManagerBuilderWrapper&>(Builder);
 207   const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts();
 208   PM.add(createMemorySanitizerPass(CGOpts.SanitizeMemoryTrackOrigins));
 209
 210   // MemorySanitizer inserts complex instrumentation that mostly follows
 211   // the logic of the original code, but operates on "shadow" values.
 212   // It can benefit from re-running some general purpose optimization passes.
 213   if (Builder.OptLevel > 0) {
 214     PM.add(createEarlyCSEPass());
 215     PM.add(createReassociatePass());
 216     PM.add(createLICMPass());
 217     PM.add(createGVNPass());
 218     PM.add(createInstructionCombiningPass());
 219     PM.add(createDeadStoreEliminationPass());
 220   }
 221 }
 222
 223 static void addThreadSanitizerPass(const PassManagerBuilder &Builder,
 224                                    legacy::PassManagerBase &PM) {
 225   PM.add(createThreadSanitizerPass());
 226 }
 227
 228 static void addDataFlowSanitizerPass(const PassManagerBuilder &Builder,
 229                                      legacy::PassManagerBase &PM) {
 230   const PassManagerBuilderWrapper &BuilderWrapper =
 231       static_cast<const PassManagerBuilderWrapper&>(Builder);
 232   const LangOptions &LangOpts = BuilderWrapper.getLangOpts();
 233   PM.add(createDataFlowSanitizerPass(LangOpts.SanitizerBlacklistFiles));
 234 }
 235
 236 static void addEfficiencySanitizerPass(const PassManagerBuilder &Builder,
 237                                        legacy::PassManagerBase &PM) {
 238   const PassManagerBuilderWrapper &BuilderWrapper =
 239       static_cast<const PassManagerBuilderWrapper&>(Builder);
 240   const LangOptions &LangOpts = BuilderWrapper.getLangOpts();
 241   EfficiencySanitizerOptions Opts;
 242   if (LangOpts.Sanitize.has(SanitizerKind::EfficiencyCacheFrag))
 243     Opts.ToolType = EfficiencySanitizerOptions::ESAN_CacheFrag;
 244   else if (LangOpts.Sanitize.has(SanitizerKind::EfficiencyWorkingSet))
 245     Opts.ToolType = EfficiencySanitizerOptions::ESAN_WorkingSet;
 246   PM.add(createEfficiencySanitizerPass(Opts));
 247 }
 248
 249 static TargetLibraryInfoImpl *createTLII(llvm::Triple &TargetTriple,
 250                                          const CodeGenOptions &CodeGenOpts) {
 251   TargetLibraryInfoImpl *TLII = new TargetLibraryInfoImpl(TargetTriple);
 252   if (!CodeGenOpts.SimplifyLibCalls)
 253     TLII->disableAllFunctions();
 254   else {
 255     // Disable individual libc/libm calls in TargetLibraryInfo.
 256     LibFunc::Func F;
 257     for (auto &FuncName : CodeGenOpts.getNoBuiltinFuncs())
 258       if (TLII->getLibFunc(FuncName, F))
 259         TLII->setUnavailable(F);
 260   }
 261
 262   switch (CodeGenOpts.getVecLib()) {
 263   case CodeGenOptions::Accelerate:
 264     TLII->addVectorizableFunctionsFromVecLib(TargetLibraryInfoImpl::Accelerate);
 265     break;
 266   default:
 267     break;
 268   }
 269   return TLII;
 270 }
 271
 272 static void addSymbolRewriterPass(const CodeGenOptions &Opts,
 273                                   legacy::PassManager *MPM) {
 274   llvm::SymbolRewriter::RewriteDescriptorList DL;
 275
 276   llvm::SymbolRewriter::RewriteMapParser MapParser;
 277   for (const auto &MapFile : Opts.RewriteMapFiles)
 278     MapParser.parse(MapFile, &DL);
 279
 280   MPM->add(createRewriteSymbolsPass(DL));
 281 }
 282
 283 void EmitAssemblyHelper::CreatePasses(legacy::PassManager &MPM,
 284                                       legacy::FunctionPassManager &FPM,
 285                                       ModuleSummaryIndex *ModuleSummary) {
 286   if (CodeGenOpts.DisableLLVMPasses)
 287     return;
 288
 289   unsigned OptLevel = CodeGenOpts.OptimizationLevel;
 290   CodeGenOptions::InliningMethod Inlining = CodeGenOpts.getInlining();
 291
 292   // Handle disabling of LLVM optimization, where we want to preserve the
 293   // internal module before any optimization.
 294   if (CodeGenOpts.DisableLLVMOpts) {
 295     OptLevel = 0;
 296     Inlining = CodeGenOpts.NoInlining;
 297   }
 298
 299   PassManagerBuilderWrapper PMBuilder(CodeGenOpts, LangOpts);
 300
 301   // Figure out TargetLibraryInfo.
 302   Triple TargetTriple(TheModule->getTargetTriple());
 303   PMBuilder.LibraryInfo = createTLII(TargetTriple, CodeGenOpts);
 304
 305   switch (Inlining) {
 306   case CodeGenOptions::NoInlining:
 307     break;
 308   case CodeGenOptions::NormalInlining:
 309   case CodeGenOptions::OnlyHintInlining: {
 310     PMBuilder.Inliner =
 311         createFunctionInliningPass(OptLevel, CodeGenOpts.OptimizeSize);
 312     break;
 313   }
 314   case CodeGenOptions::OnlyAlwaysInlining:
 315     // Respect always_inline.
 316     if (OptLevel == 0)
 317       // Do not insert lifetime intrinsics at -O0.
 318       PMBuilder.Inliner = createAlwaysInlinerPass(false);
 319     else
 320       PMBuilder.Inliner = createAlwaysInlinerPass();
 321     break;
 322   }
 323
 324   PMBuilder.OptLevel = OptLevel;
 325   PMBuilder.SizeLevel = CodeGenOpts.OptimizeSize;
 326   PMBuilder.BBVectorize = CodeGenOpts.VectorizeBB;
 327   PMBuilder.SLPVectorize = CodeGenOpts.VectorizeSLP;
 328   PMBuilder.LoopVectorize = CodeGenOpts.VectorizeLoop;
 329
 330   PMBuilder.DisableUnrollLoops = !CodeGenOpts.UnrollLoops;
 331   PMBuilder.MergeFunctions = CodeGenOpts.MergeFunctions;
 332   PMBuilder.PrepareForThinLTO = CodeGenOpts.EmitSummaryIndex;
 333   PMBuilder.PrepareForLTO = CodeGenOpts.PrepareForLTO;
 334   PMBuilder.RerollLoops = CodeGenOpts.RerollLoops;
 335
 336   // If we are performing a ThinLTO importing compile, invoke the LTO
 337   // pipeline and pass down the in-memory module summary index.
 338   if (ModuleSummary) {
 339     PMBuilder.ModuleSummary = ModuleSummary;
 340     PMBuilder.populateThinLTOPassManager(MPM);
 341     return;
 342   }
 343
 344   // Add target-specific passes that need to run as early as possible.
 345   if (TM)
 346     PMBuilder.addExtension(
 347         PassManagerBuilder::EP_EarlyAsPossible,
 348         [&](const PassManagerBuilder &, legacy::PassManagerBase &PM) {
 349           TM->addEarlyAsPossiblePasses(PM);
 350         });
 351
 352   PMBuilder.addExtension(PassManagerBuilder::EP_EarlyAsPossible,
 353                          addAddDiscriminatorsPass);
 354
 355   // In ObjC ARC mode, add the main ARC optimization passes.
 356   if (LangOpts.ObjCAutoRefCount) {
 357     PMBuilder.addExtension(PassManagerBuilder::EP_EarlyAsPossible,
 358                            addObjCARCExpandPass);
 359     PMBuilder.addExtension(PassManagerBuilder::EP_ModuleOptimizerEarly,
 360                            addObjCARCAPElimPass);
 361     PMBuilder.addExtension(PassManagerBuilder::EP_ScalarOptimizerLate,
 362                            addObjCARCOptPass);
 363   }
 364
 365   if (LangOpts.Sanitize.has(SanitizerKind::LocalBounds)) {
 366     PMBuilder.addExtension(PassManagerBuilder::EP_ScalarOptimizerLate,
 367                            addBoundsCheckingPass);
 368     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
 369                            addBoundsCheckingPass);
 370   }
 371
 372   if (CodeGenOpts.SanitizeCoverageType ||
 373       CodeGenOpts.SanitizeCoverageIndirectCalls ||
 374       CodeGenOpts.SanitizeCoverageTraceCmp) {
 375     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
 376                            addSanitizerCoveragePass);
 377     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
 378                            addSanitizerCoveragePass);
 379   }
 380
 381   if (LangOpts.Sanitize.has(SanitizerKind::Address)) {
 382     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
 383                            addAddressSanitizerPasses);
 384     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
 385                            addAddressSanitizerPasses);
 386   }
 387
 388   if (LangOpts.Sanitize.has(SanitizerKind::KernelAddress)) {
 389     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
 390                            addKernelAddressSanitizerPasses);
 391     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
 392                            addKernelAddressSanitizerPasses);
 393   }
 394
 395   if (LangOpts.Sanitize.has(SanitizerKind::Memory)) {
 396     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
 397                            addMemorySanitizerPass);
 398     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
 399                            addMemorySanitizerPass);
 400   }
 401
 402   if (LangOpts.Sanitize.has(SanitizerKind::Thread)) {
 403     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
 404                            addThreadSanitizerPass);
 405     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
 406                            addThreadSanitizerPass);
 407   }
 408
 409   if (LangOpts.Sanitize.has(SanitizerKind::DataFlow)) {
 410     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
 411                            addDataFlowSanitizerPass);
 412     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
 413                            addDataFlowSanitizerPass);
 414   }
 415
 416   if (LangOpts.Sanitize.hasOneOf(SanitizerKind::Efficiency)) {
 417     PMBuilder.addExtension(PassManagerBuilder::EP_OptimizerLast,
 418                            addEfficiencySanitizerPass);
 419     PMBuilder.addExtension(PassManagerBuilder::EP_EnabledOnOptLevel0,
 420                            addEfficiencySanitizerPass);
 421   }
 422
 423   // Set up the per-function pass manager.
 424   if (CodeGenOpts.VerifyModule)
 425     FPM.add(createVerifierPass());
 426
 427   // Set up the per-module pass manager.
 428   if (!CodeGenOpts.RewriteMapFiles.empty())
 429     addSymbolRewriterPass(CodeGenOpts, &MPM);
 430
 431   if (!CodeGenOpts.DisableGCov &&
 432       (CodeGenOpts.EmitGcovArcs || CodeGenOpts.EmitGcovNotes)) {
 433     // Not using 'GCOVOptions::getDefault' allows us to avoid exiting if
 434     // LLVM's -default-gcov-version flag is set to something invalid.
 435     GCOVOptions Options;
 436     Options.EmitNotes = CodeGenOpts.EmitGcovNotes;
 437     Options.EmitData = CodeGenOpts.EmitGcovArcs;
 438     memcpy(Options.Version, CodeGenOpts.CoverageVersion, 4);
 439     Options.UseCfgChecksum = CodeGenOpts.CoverageExtraChecksum;
 440     Options.NoRedZone = CodeGenOpts.DisableRedZone;
 441     Options.FunctionNamesInData =
 442         !CodeGenOpts.CoverageNoFunctionNamesInData;
 443     Options.ExitBlockBeforeBody = CodeGenOpts.CoverageExitBlockBeforeBody;
 444     MPM.add(createGCOVProfilerPass(Options));
 445     if (CodeGenOpts.getDebugInfo() == codegenoptions::NoDebugInfo)
 446       MPM.add(createStripSymbolsPass(true));
 447   }
 448
 449   if (CodeGenOpts.hasProfileClangInstr()) {
 450     InstrProfOptions Options;
 451     Options.NoRedZone = CodeGenOpts.DisableRedZone;
 452     Options.InstrProfileOutput = CodeGenOpts.InstrProfileOutput;
 453     MPM.add(createInstrProfilingLegacyPass(Options));
 454   }
 455   if (CodeGenOpts.hasProfileIRInstr()) {
 456     if (!CodeGenOpts.InstrProfileOutput.empty())
 457       PMBuilder.PGOInstrGen = CodeGenOpts.InstrProfileOutput;
 458     else
 459       PMBuilder.PGOInstrGen = "default.profraw";
 460   }
 461   if (CodeGenOpts.hasProfileIRUse())
 462     PMBuilder.PGOInstrUse = CodeGenOpts.ProfileInstrumentUsePath;
 463
 464   if (!CodeGenOpts.SampleProfileFile.empty()) {
 465     MPM.add(createPruneEHPass());
 466     MPM.add(createSampleProfileLoaderPass(CodeGenOpts.SampleProfileFile));
 467     PMBuilder.addExtension(PassManagerBuilder::EP_EarlyAsPossible,
 468                            addCleanupPassesForSampleProfiler);
 469   }
 470
 471   PMBuilder.populateFunctionPassManager(FPM);
 472   PMBuilder.populateModulePassManager(MPM);
 473 }
 474
 475 void EmitAssemblyHelper::setCommandLineOpts() {
 476   SmallVector<const char *, 16> BackendArgs;
 477   BackendArgs.push_back("clang"); // Fake program name.
 478   if (!CodeGenOpts.DebugPass.empty()) {
 479     BackendArgs.push_back("-debug-pass");
 480     BackendArgs.push_back(CodeGenOpts.DebugPass.c_str());
 481   }
 482   if (!CodeGenOpts.LimitFloatPrecision.empty()) {
 483     BackendArgs.push_back("-limit-float-precision");
 484     BackendArgs.push_back(CodeGenOpts.LimitFloatPrecision.c_str());
 485   }
 486   for (const std::string &BackendOption : CodeGenOpts.BackendOptions)
 487     BackendArgs.push_back(BackendOption.c_str());
 488   BackendArgs.push_back(nullptr);
 489   llvm::cl::ParseCommandLineOptions(BackendArgs.size() - 1,
 490                                     BackendArgs.data());
 491 }
 492
 493 void EmitAssemblyHelper::CreateTargetMachine(bool MustCreateTM) {
 494   // Create the TargetMachine for generating code.
 495   std::string Error;
 496   std::string Triple = TheModule->getTargetTriple();
 497   const llvm::Target *TheTarget = TargetRegistry::lookupTarget(Triple, Error);
 498   if (!TheTarget) {
 499     if (MustCreateTM)
 500       Diags.Report(diag::err_fe_unable_to_create_target) << Error;
 501     return;
 502   }
 503
 504   unsigned CodeModel =
 505     llvm::StringSwitch<unsigned>(CodeGenOpts.CodeModel)
 506       .Case("small", llvm::CodeModel::Small)
 507       .Case("kernel", llvm::CodeModel::Kernel)
 508       .Case("medium", llvm::CodeModel::Medium)
 509       .Case("large", llvm::CodeModel::Large)
 510       .Case("default", llvm::CodeModel::Default)
 511       .Default(~0u);
 512   assert(CodeModel != ~0u && "invalid code model!");
 513   llvm::CodeModel::Model CM = static_cast<llvm::CodeModel::Model>(CodeModel);
 514
 515   std::string FeaturesStr =
 516       llvm::join(TargetOpts.Features.begin(), TargetOpts.Features.end(), ",");
 517
 518   // Keep this synced with the equivalent code in tools/driver/cc1as_main.cpp.
 519   llvm::Optional<llvm::Reloc::Model> RM;
 520   if (CodeGenOpts.RelocationModel == "static") {
 521     RM = llvm::Reloc::Static;
 522   } else if (CodeGenOpts.RelocationModel == "pic") {
 523     RM = llvm::Reloc::PIC_;
 524   } else {
 525     assert(CodeGenOpts.RelocationModel == "dynamic-no-pic" &&
 526            "Invalid PIC model!");
 527     RM = llvm::Reloc::DynamicNoPIC;
 528   }
 529
 530   CodeGenOpt::Level OptLevel = CodeGenOpt::Default;
 531   switch (CodeGenOpts.OptimizationLevel) {
 532   default: break;
 533   case 0: OptLevel = CodeGenOpt::None; break;
 534   case 3: OptLevel = CodeGenOpt::Aggressive; break;
 535   }
 536
 537   llvm::TargetOptions Options;
 538
 539   if (!TargetOpts.Reciprocals.empty())
 540     Options.Reciprocals = TargetRecip(TargetOpts.Reciprocals);
 541
 542   Options.ThreadModel =
 543     llvm::StringSwitch<llvm::ThreadModel::Model>(CodeGenOpts.ThreadModel)
 544       .Case("posix", llvm::ThreadModel::POSIX)
 545       .Case("single", llvm::ThreadModel::Single);
 546
 547   // Set float ABI type.
 548   assert((CodeGenOpts.FloatABI == "soft" || CodeGenOpts.FloatABI == "softfp" ||
 549           CodeGenOpts.FloatABI == "hard" || CodeGenOpts.FloatABI.empty()) &&
 550          "Invalid Floating Point ABI!");
 551   Options.FloatABIType =
 552       llvm::StringSwitch<llvm::FloatABI::ABIType>(CodeGenOpts.FloatABI)
 553           .Case("soft", llvm::FloatABI::Soft)
 554           .Case("softfp", llvm::FloatABI::Soft)
 555           .Case("hard", llvm::FloatABI::Hard)
 556           .Default(llvm::FloatABI::Default);
 557
 558   // Set FP fusion mode.
 559   switch (CodeGenOpts.getFPContractMode()) {
 560   case CodeGenOptions::FPC_Off:
 561     Options.AllowFPOpFusion = llvm::FPOpFusion::Strict;
 562     break;
 563   case CodeGenOptions::FPC_On:
 564     Options.AllowFPOpFusion = llvm::FPOpFusion::Standard;
 565     break;
 566   case CodeGenOptions::FPC_Fast:
 567     Options.AllowFPOpFusion = llvm::FPOpFusion::Fast;
 568     break;
 569   }
 570
 571   Options.UseInitArray = CodeGenOpts.UseInitArray;
 572   Options.DisableIntegratedAS = CodeGenOpts.DisableIntegratedAS;
 573   Options.CompressDebugSections = CodeGenOpts.CompressDebugSections;
 574   Options.RelaxELFRelocations = CodeGenOpts.RelaxELFRelocations;
 575
 576   // Set EABI version.
 577   Options.EABIVersion = llvm::StringSwitch<llvm::EABI>(TargetOpts.EABIVersion)
 578                             .Case("4", llvm::EABI::EABI4)
 579                             .Case("5", llvm::EABI::EABI5)
 580                             .Case("gnu", llvm::EABI::GNU)
 581                             .Default(llvm::EABI::Default);
 582
 583   if (LangOpts.SjLjExceptions)
 584     Options.ExceptionModel = llvm::ExceptionHandling::SjLj;
 585
 586   Options.LessPreciseFPMADOption = CodeGenOpts.LessPreciseFPMAD;
 587   Options.NoInfsFPMath = CodeGenOpts.NoInfsFPMath;
 588   Options.NoNaNsFPMath = CodeGenOpts.NoNaNsFPMath;
 589   Options.NoZerosInBSS = CodeGenOpts.NoZeroInitializedInBSS;
 590   Options.UnsafeFPMath = CodeGenOpts.UnsafeFPMath;
 591   Options.StackAlignmentOverride = CodeGenOpts.StackAlignment;
 592   Options.FunctionSections = CodeGenOpts.FunctionSections;
 593   Options.DataSections = CodeGenOpts.DataSections;
 594   Options.UniqueSectionNames = CodeGenOpts.UniqueSectionNames;
 595   Options.EmulatedTLS = CodeGenOpts.EmulatedTLS;
 596   Options.DebuggerTuning = CodeGenOpts.getDebuggerTuning();
 597
 598   Options.MCOptions.MCRelaxAll = CodeGenOpts.RelaxAll;
 599   Options.MCOptions.MCSaveTempLabels = CodeGenOpts.SaveTempLabels;
 600   Options.MCOptions.MCUseDwarfDirectory = !CodeGenOpts.NoDwarfDirectoryAsm;
 601   Options.MCOptions.MCNoExecStack = CodeGenOpts.NoExecStack;
 602   Options.MCOptions.MCIncrementalLinkerCompatible =
 603       CodeGenOpts.IncrementalLinkerCompatible;
 604   Options.MCOptions.MCFatalWarnings = CodeGenOpts.FatalWarnings;
 605   Options.MCOptions.AsmVerbose = CodeGenOpts.AsmVerbose;
 606   Options.MCOptions.ABIName = TargetOpts.ABI;
 607
 608   TM.reset(TheTarget->createTargetMachine(Triple, TargetOpts.CPU, FeaturesStr,
 609                                           Options, RM, CM, OptLevel));
 610 }
 611
 612 bool EmitAssemblyHelper::AddEmitPasses(legacy::PassManager &CodeGenPasses,
 613                                        BackendAction Action,
 614                                        raw_pwrite_stream &OS) {
 615   // Add LibraryInfo.
 616   llvm::Triple TargetTriple(TheModule->getTargetTriple());
 617   std::unique_ptr<TargetLibraryInfoImpl> TLII(
 618       createTLII(TargetTriple, CodeGenOpts));
 619   CodeGenPasses.add(new TargetLibraryInfoWrapperPass(*TLII));
 620
 621   // Normal mode, emit a .s or .o file by running the code generator. Note,
 622   // this also adds codegenerator level optimization passes.
 623   TargetMachine::CodeGenFileType CGFT = TargetMachine::CGFT_AssemblyFile;
 624   if (Action == Backend_EmitObj)
 625     CGFT = TargetMachine::CGFT_ObjectFile;
 626   else if (Action == Backend_EmitMCNull)
 627     CGFT = TargetMachine::CGFT_Null;
 628   else
 629     assert(Action == Backend_EmitAssembly && "Invalid action!");
 630
 631   // Add ObjC ARC final-cleanup optimizations. This is done as part of the
 632   // "codegen" passes so that it isn't run multiple times when there is
 633   // inlining happening.
 634   if (CodeGenOpts.OptimizationLevel > 0)
 635     CodeGenPasses.add(createObjCARCContractPass());
 636
 637   if (TM->addPassesToEmitFile(CodeGenPasses, OS, CGFT,
 638                               /*DisableVerify=*/!CodeGenOpts.VerifyModule)) {
 639     Diags.Report(diag::err_fe_unable_to_interface_with_target);
 640     return false;
 641   }
 642
 643   return true;
 644 }
 645
 646 void EmitAssemblyHelper::EmitAssembly(BackendAction Action,
 647                                       std::unique_ptr<raw_pwrite_stream> OS) {
 648   TimeRegion Region(llvm::TimePassesIsEnabled ? &CodeGenerationTime : nullptr);
 649
 650   setCommandLineOpts();
 651
 652   bool UsesCodeGen = (Action != Backend_EmitNothing &&
 653                       Action != Backend_EmitBC &&
 654                       Action != Backend_EmitLL);
 655   CreateTargetMachine(UsesCodeGen);
 656
 657   if (UsesCodeGen && !TM)
 658     return;
 659   if (TM)
 660     TheModule->setDataLayout(TM->createDataLayout());
 661
 662   // If we are performing a ThinLTO importing compile, load the function
 663   // index into memory and pass it into CreatePasses, which will add it
 664   // to the PassManagerBuilder and invoke LTO passes.
 665   std::unique_ptr<ModuleSummaryIndex> ModuleSummary;
 666   if (!CodeGenOpts.ThinLTOIndexFile.empty()) {
 667     ErrorOr<std::unique_ptr<ModuleSummaryIndex>> IndexOrErr =
 668         llvm::getModuleSummaryIndexForFile(
 669             CodeGenOpts.ThinLTOIndexFile, [&](const DiagnosticInfo &DI) {
 670               TheModule->getContext().diagnose(DI);
 671             });
 672     if (std::error_code EC = IndexOrErr.getError()) {
 673       std::string Error = EC.message();
 674       errs() << "Error loading index file '" << CodeGenOpts.ThinLTOIndexFile
 675              << "': " << Error << "\n";
 676       return;
 677     }
 678     ModuleSummary = std::move(IndexOrErr.get());
 679     assert(ModuleSummary && "Expected non-empty module summary index");
 680   }
 681
 682   legacy::PassManager PerModulePasses;
 683   PerModulePasses.add(
 684       createTargetTransformInfoWrapperPass(getTargetIRAnalysis()));
 685
 686   legacy::FunctionPassManager PerFunctionPasses(TheModule);
 687   PerFunctionPasses.add(
 688       createTargetTransformInfoWrapperPass(getTargetIRAnalysis()));
 689
 690   CreatePasses(PerModulePasses, PerFunctionPasses, ModuleSummary.get());
 691
 692   legacy::PassManager CodeGenPasses;
 693   CodeGenPasses.add(
 694       createTargetTransformInfoWrapperPass(getTargetIRAnalysis()));
 695
 696   switch (Action) {
 697   case Backend_EmitNothing:
 698     break;
 699
 700   case Backend_EmitBC:
 701     PerModulePasses.add(createBitcodeWriterPass(
 702         *OS, CodeGenOpts.EmitLLVMUseLists, CodeGenOpts.EmitSummaryIndex,
 703         CodeGenOpts.EmitSummaryIndex));
 704     break;
 705
 706   case Backend_EmitLL:
 707     PerModulePasses.add(
 708         createPrintModulePass(*OS, "", CodeGenOpts.EmitLLVMUseLists));
 709     break;
 710
 711   default:
 712     if (!AddEmitPasses(CodeGenPasses, Action, *OS))
 713       return;
 714   }
 715
 716   // Before executing passes, print the final values of the LLVM options.
 717   cl::PrintOptionValues();
 718
 719   // Run passes. For now we do all passes at once, but eventually we
 720   // would like to have the option of streaming code generation.
 721
 722   {
 723     PrettyStackTraceString CrashInfo("Per-function optimization");
 724
 725     PerFunctionPasses.doInitialization();
 726     for (Function &F : *TheModule)
 727       if (!F.isDeclaration())
 728         PerFunctionPasses.run(F);
 729     PerFunctionPasses.doFinalization();
 730   }
 731
 732   {
 733     PrettyStackTraceString CrashInfo("Per-module optimization passes");
 734     PerModulePasses.run(*TheModule);
 735   }
 736
 737   {
 738     PrettyStackTraceString CrashInfo("Code generation");
 739     CodeGenPasses.run(*TheModule);
 740   }
 741 }
 742
 743 void clang::EmitBackendOutput(DiagnosticsEngine &Diags,
 744                               const CodeGenOptions &CGOpts,
 745                               const clang::TargetOptions &TOpts,
 746                               const LangOptions &LOpts, const llvm::DataLayout &TDesc,
 747                               Module *M, BackendAction Action,
 748                               std::unique_ptr<raw_pwrite_stream> OS) {
 749   EmitAssemblyHelper AsmHelper(Diags, CGOpts, TOpts, LOpts, M);
 750
 751   AsmHelper.EmitAssembly(Action, std::move(OS));
 752
 753   // Verify clang's TargetInfo DataLayout against the LLVM TargetMachine's
 754   // DataLayout.
 755   if (AsmHelper.TM) {
 756     std::string DLDesc = M->getDataLayout().getStringRepresentation();
 757     if (DLDesc != TDesc.getStringRepresentation()) {
 758       unsigned DiagID = Diags.getCustomDiagID(
 759           DiagnosticsEngine::Error, "backend data layout '%0' does not match "
 760                                     "expected target description '%1'");
 761       Diags.Report(DiagID) << DLDesc << TDesc.getStringRepresentation();
 762     }
 763   }
 764 }
 765
 766 static const char* getSectionNameForBitcode(const Triple &T) {
 767   switch (T.getObjectFormat()) {
 768   case Triple::MachO:
 769     return "__LLVM,__bitcode";
 770   case Triple::COFF:
 771   case Triple::ELF:
 772   case Triple::UnknownObjectFormat:
 773     return ".llvmbc";
 774   }
 775   llvm_unreachable("Unimplemented ObjectFormatType");
 776 }
 777
 778 static const char* getSectionNameForCommandline(const Triple &T) {
 779   switch (T.getObjectFormat()) {
 780   case Triple::MachO:
 781     return "__LLVM,__cmdline";
 782   case Triple::COFF:
 783   case Triple::ELF:
 784   case Triple::UnknownObjectFormat:
 785     return ".llvmcmd";
 786   }
 787   llvm_unreachable("Unimplemented ObjectFormatType");
 788 }
 789
 790 // With -fembed-bitcode, save a copy of the llvm IR as data in the
 791 // __LLVM,__bitcode section.
 792 void clang::EmbedBitcode(llvm::Module *M, const CodeGenOptions &CGOpts,
 793                          llvm::MemoryBufferRef Buf) {
 794   if (CGOpts.getEmbedBitcode() == CodeGenOptions::Embed_Off)
 795     return;
 796
 797   // Save llvm.compiler.used and remote it.
 798   SmallVector<Constant*, 2> UsedArray;
 799   SmallSet<GlobalValue*, 4> UsedGlobals;
 800   Type *UsedElementType = Type::getInt8Ty(M->getContext())->getPointerTo(0);
 801   GlobalVariable *Used = collectUsedGlobalVariables(*M, UsedGlobals, true);
 802   for (auto *GV : UsedGlobals) {
 803     if (GV->getName() != "llvm.embedded.module" &&
 804         GV->getName() != "llvm.cmdline")
 805       UsedArray.push_back(
 806           ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
 807   }
 808   if (Used)
 809     Used->eraseFromParent();
 810
 811   // Embed the bitcode for the llvm module.
 812   std::string Data;
 813   ArrayRef<uint8_t> ModuleData;
 814   Triple T(M->getTargetTriple());
 815   // Create a constant that contains the bitcode.
 816   // In case of embedding a marker, ignore the input Buf and use the empty
 817   // ArrayRef. It is also legal to create a bitcode marker even Buf is empty.
 818   if (CGOpts.getEmbedBitcode() != CodeGenOptions::Embed_Marker) {
 819     if (!isBitcode((const unsigned char *)Buf.getBufferStart(),
 820                    (const unsigned char *)Buf.getBufferEnd())) {
 821       // If the input is LLVM Assembly, bitcode is produced by serializing
 822       // the module. Use-lists order need to be perserved in this case.
 823       llvm::raw_string_ostream OS(Data);
 824       llvm::WriteBitcodeToFile(M, OS, /* ShouldPreserveUseListOrder */ true);
 825       ModuleData =
 826           ArrayRef<uint8_t>((const uint8_t *)OS.str().data(), OS.str().size());
 827     } else
 828       // If the input is LLVM bitcode, write the input byte stream directly.
 829       ModuleData = ArrayRef<uint8_t>((const uint8_t *)Buf.getBufferStart(),
 830                                      Buf.getBufferSize());
 831   }
 832   llvm::Constant *ModuleConstant =
 833       llvm::ConstantDataArray::get(M->getContext(), ModuleData);
 834   llvm::GlobalVariable *GV = new llvm::GlobalVariable(
 835       *M, ModuleConstant->getType(), true, llvm::GlobalValue::PrivateLinkage,
 836       ModuleConstant);
 837   GV->setSection(getSectionNameForBitcode(T));
 838   UsedArray.push_back(
 839       ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
 840   if (llvm::GlobalVariable *Old =
 841           M->getGlobalVariable("llvm.embedded.module", true)) {
 842     assert(Old->hasOneUse() &&
 843            "llvm.embedded.module can only be used once in llvm.compiler.used");
 844     GV->takeName(Old);
 845     Old->eraseFromParent();
 846   } else {
 847     GV->setName("llvm.embedded.module");
 848   }
 849
 850   // Skip if only bitcode needs to be embedded.
 851   if (CGOpts.getEmbedBitcode() != CodeGenOptions::Embed_Bitcode) {
 852     // Embed command-line options.
 853     ArrayRef<uint8_t> CmdData(const_cast<uint8_t *>(CGOpts.CmdArgs.data()),
 854                               CGOpts.CmdArgs.size());
 855     llvm::Constant *CmdConstant =
 856       llvm::ConstantDataArray::get(M->getContext(), CmdData);
 857     GV = new llvm::GlobalVariable(*M, CmdConstant->getType(), true,
 858                                   llvm::GlobalValue::PrivateLinkage,
 859                                   CmdConstant);
 860     GV->setSection(getSectionNameForCommandline(T));
 861     UsedArray.push_back(
 862         ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
 863     if (llvm::GlobalVariable *Old =
 864             M->getGlobalVariable("llvm.cmdline", true)) {
 865       assert(Old->hasOneUse() &&
 866              "llvm.cmdline can only be used once in llvm.compiler.used");
 867       GV->takeName(Old);
 868       Old->eraseFromParent();
 869     } else {
 870       GV->setName("llvm.cmdline");
 871     }
 872   }
 873
 874   if (UsedArray.empty())
 875     return;
 876
 877   // Recreate llvm.compiler.used.
 878   ArrayType *ATy = ArrayType::get(UsedElementType, UsedArray.size());
 879   auto *NewUsed = new GlobalVariable(
 880       *M, ATy, false, llvm::GlobalValue::AppendingLinkage,
 881       llvm::ConstantArray::get(ATy, UsedArray), "llvm.compiler.used");
 882   NewUsed->setSection("llvm.metadata");
 883 }