C++ LLVMContext::setDiscardValueNames方法代码示例

LTOCodeGenerator::LTOCodeGenerator(LLVMContext &Context)
    : Context(Context), MergedModule(new Module("ld-temp.o", Context)),
      TheLinker(new Linker(*MergedModule)) {
  Context.setDiscardValueNames(LTODiscardValueNames);
  Context.enableDebugTypeODRUniquing();
  initializeLTOPasses();
}

// Main entry point for the ThinLTO processing
void ThinLTOCodeGenerator::run() {
  // Sequential linking phase
  auto Index = linkCombinedIndex();

  // Save temps: index.
  if (!SaveTempsDir.empty()) {
    auto SaveTempPath = SaveTempsDir + "index.bc";
    std::error_code EC;
    raw_fd_ostream OS(SaveTempPath, EC, sys::fs::F_None);
    if (EC)
      report_fatal_error(Twine("Failed to open ") + SaveTempPath +
                         " to save optimized bitcode\n");
    WriteIndexToFile(*Index, OS);
  }

  // Prepare the resulting object vector
  assert(ProducedBinaries.empty() && "The generator should not be reused");
  ProducedBinaries.resize(Modules.size());

  // Prepare the module map.
  auto ModuleMap = generateModuleMap(Modules);

  // Parallel optimizer + codegen
  {
    ThreadPool Pool(ThreadCount);
    int count = 0;
    for (auto &ModuleBuffer : Modules) {
      Pool.async([&](int count) {
        LLVMContext Context;
        Context.setDiscardValueNames(LTODiscardValueNames);

        // Parse module now
        auto TheModule = loadModuleFromBuffer(ModuleBuffer, Context, false);

        // Save temps: original file.
        if (!SaveTempsDir.empty()) {
          saveTempBitcode(*TheModule, SaveTempsDir, count, ".0.original.bc");
        }

        ProducedBinaries[count] = ProcessThinLTOModule(
            *TheModule, *Index, ModuleMap, *TMBuilder.create(), CacheOptions,
            SaveTempsDir, count);
      }, count);
      count++;
    }
  }

  // If statistics were requested, print them out now.
  if (llvm::AreStatisticsEnabled())
    llvm::PrintStatistics();
}

// main - Entry point for the llc compiler.
//
int main(int argc, char **argv) {
  sys::PrintStackTraceOnErrorSignal(argv[0]);
  PrettyStackTraceProgram X(argc, argv);

  // Enable debug stream buffering.
  EnableDebugBuffering = true;

  LLVMContext Context;
  llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.

  // Initialize targets first, so that --version shows registered targets.
  InitializeAllTargets();
  InitializeAllTargetMCs();
  InitializeAllAsmPrinters();
  InitializeAllAsmParsers();

  // Initialize codegen and IR passes used by llc so that the -print-after,
  // -print-before, and -stop-after options work.
  PassRegistry *Registry = PassRegistry::getPassRegistry();
  initializeCore(*Registry);
  initializeCodeGen(*Registry);
  initializeLoopStrengthReducePass(*Registry);
  initializeLowerIntrinsicsPass(*Registry);
  initializeCountingFunctionInserterPass(*Registry);
  initializeUnreachableBlockElimLegacyPassPass(*Registry);
  initializeConstantHoistingLegacyPassPass(*Registry);

  // Register the target printer for --version.
  cl::AddExtraVersionPrinter(TargetRegistry::printRegisteredTargetsForVersion);

  cl::ParseCommandLineOptions(argc, argv, "llvm system compiler\n");

  Context.setDiscardValueNames(DiscardValueNames);

  // Set a diagnostic handler that doesn't exit on the first error
  bool HasError = false;
  Context.setDiagnosticHandler(DiagnosticHandler, &HasError);

  // Compile the module TimeCompilations times to give better compile time
  // metrics.
  for (unsigned I = TimeCompilations; I; --I)
    if (int RetVal = compileModule(argv, Context))
      return RetVal;
  return 0;
}

/// Perform the ThinLTO backend on a single module, invoking the LTO and codegen
/// pipelines.
static void thinLTOBackendTask(claimed_file &F, const void *View,
                               ld_plugin_input_file &File,
                               raw_fd_ostream *ApiFile,
                               const ModuleSummaryIndex &CombinedIndex,
                               raw_fd_ostream *OS, unsigned TaskID) {
  // Need to use a separate context for each task
  LLVMContext Context;
  Context.setDiscardValueNames(options::DiscardValueNames);
  Context.enableDebugTypeODRUniquing(); // Merge debug info types.
  Context.setDiagnosticHandler(diagnosticHandlerForContext, nullptr, true);

  std::unique_ptr<llvm::Module> NewModule(new llvm::Module(File.name, Context));
  IRMover L(*NewModule.get());

  StringSet<> Dummy;
  if (linkInModule(Context, L, F, View, File, ApiFile, Dummy, Dummy))
    message(LDPL_FATAL, "Failed to rename module for ThinLTO");
  if (renameModuleForThinLTO(*NewModule, CombinedIndex))
    message(LDPL_FATAL, "Failed to rename module for ThinLTO");

  CodeGen codeGen(std::move(NewModule), OS, TaskID, &CombinedIndex, File.name);
  codeGen.runAll();
}

// main - Entry point for the llc compiler.
//
int main(int argc, char **argv) {
  sys::PrintStackTraceOnErrorSignal(argv[0]);
  PrettyStackTraceProgram X(argc, argv);

  // Enable debug stream buffering.
  EnableDebugBuffering = true;

  LLVMContext Context;
  llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.

  // Initialize targets first, so that --version shows registered targets.
  InitializeAllTargets();
  InitializeAllTargetMCs();
  InitializeAllAsmPrinters();
  InitializeAllAsmParsers();

  // Initialize codegen and IR passes used by llc so that the -print-after,
  // -print-before, and -stop-after options work.
  PassRegistry *Registry = PassRegistry::getPassRegistry();
  initializeCore(*Registry);
  initializeCodeGen(*Registry);
  initializeLoopStrengthReducePass(*Registry);
  initializeLowerIntrinsicsPass(*Registry);
  initializeCountingFunctionInserterPass(*Registry);
  initializeUnreachableBlockElimLegacyPassPass(*Registry);
  initializeConstantHoistingLegacyPassPass(*Registry);
  initializeScalarOpts(*Registry);
  initializeVectorization(*Registry);

  // Register the target printer for --version.
  cl::AddExtraVersionPrinter(TargetRegistry::printRegisteredTargetsForVersion);

  cl::ParseCommandLineOptions(argc, argv, "llvm system compiler\n");

  Context.setDiscardValueNames(DiscardValueNames);

  // Set a diagnostic handler that doesn't exit on the first error
  bool HasError = false;
  Context.setDiagnosticHandler(DiagnosticHandler, &HasError);
  Context.setInlineAsmDiagnosticHandler(InlineAsmDiagHandler, &HasError);

  if (PassRemarksWithHotness)
    Context.setDiagnosticHotnessRequested(true);

  std::unique_ptr<tool_output_file> YamlFile;
  if (RemarksFilename != "") {
    std::error_code EC;
    YamlFile = llvm::make_unique<tool_output_file>(RemarksFilename, EC,
                                                   sys::fs::F_None);
    if (EC) {
      errs() << EC.message() << '\n';
      return 1;
    }
    Context.setDiagnosticsOutputFile(
        llvm::make_unique<yaml::Output>(YamlFile->os()));
  }

  // Compile the module TimeCompilations times to give better compile time
  // metrics.
  for (unsigned I = TimeCompilations; I; --I)
    if (int RetVal = compileModule(argv, Context))
      return RetVal;

  if (YamlFile)
    YamlFile->keep();
  return 0;
}

/// gold informs us that all symbols have been read. At this point, we use
/// get_symbols to see if any of our definitions have been overridden by a
/// native object file. Then, perform optimization and codegen.
static ld_plugin_status allSymbolsReadHook(raw_fd_ostream *ApiFile) {
  if (Modules.empty())
    return LDPS_OK;

  if (unsigned NumOpts = options::extra.size())
    cl::ParseCommandLineOptions(NumOpts, &options::extra[0]);

  // If we are doing ThinLTO compilation, simply build the combined
  // module index/summary and emit it. We don't need to parse the modules
  // and link them in this case.
  if (options::thinlto) {
    ModuleSummaryIndex CombinedIndex;
    uint64_t NextModuleId = 0;
    for (claimed_file &F : Modules) {
      PluginInputFile InputFile(F.handle);

      std::unique_ptr<ModuleSummaryIndex> Index =
          getModuleSummaryIndexForFile(F, InputFile.file());

      // Skip files without a module summary.
      if (Index)
        CombinedIndex.mergeFrom(std::move(Index), ++NextModuleId);
    }

    std::error_code EC;
    raw_fd_ostream OS(output_name + ".thinlto.bc", EC,
                      sys::fs::OpenFlags::F_None);
    if (EC)
      message(LDPL_FATAL, "Unable to open %s.thinlto.bc for writing: %s",
              output_name.data(), EC.message().c_str());
    WriteIndexToFile(CombinedIndex, OS);
    OS.close();

    if (options::thinlto_index_only) {
      cleanup_hook();
      exit(0);
    }

    thinLTOBackends(ApiFile, CombinedIndex);
    return LDPS_OK;
  }

  LLVMContext Context;
  Context.setDiscardValueNames(options::DiscardValueNames);
  Context.enableDebugTypeODRUniquing(); // Merge debug info types.
  Context.setDiagnosticHandler(diagnosticHandlerForContext, nullptr, true);

  std::unique_ptr<Module> Combined(new Module("ld-temp.o", Context));
  IRMover L(*Combined);

  StringSet<> Internalize;
  StringSet<> Maybe;
  for (claimed_file &F : Modules) {
    PluginInputFile InputFile(F.handle);
    const void *View = getSymbolsAndView(F);
    if (!View)
      continue;
    if (linkInModule(Context, L, F, View, InputFile.file(), ApiFile,
                     Internalize, Maybe))
      message(LDPL_FATAL, "Failed to link module");
  }

  for (const auto &Name : Internalize) {
    GlobalValue *GV = Combined->getNamedValue(Name.first());
    if (GV)
      internalize(*GV);
  }

  for (const auto &Name : Maybe) {
    GlobalValue *GV = Combined->getNamedValue(Name.first());
    if (!GV)
      continue;
    GV->setLinkage(GlobalValue::LinkOnceODRLinkage);
    if (canBeOmittedFromSymbolTable(GV))
      internalize(*GV);
  }

  if (options::TheOutputType == options::OT_DISABLE)
    return LDPS_OK;

  if (options::TheOutputType != options::OT_NORMAL) {
    std::string path;
    if (options::TheOutputType == options::OT_BC_ONLY)
      path = output_name;
    else
      path = output_name + ".bc";
    saveBCFile(path, *Combined);
    if (options::TheOutputType == options::OT_BC_ONLY)
      return LDPS_OK;
  }

  CodeGen codeGen(std::move(Combined));
  codeGen.runAll();

  if (!options::extra_library_path.empty() &&
      set_extra_library_path(options::extra_library_path.c_str()) != LDPS_OK)
    message(LDPL_FATAL, "Unable to set the extra library path.");
//.........这里部分代码省略.........

//===----------------------------------------------------------------------===//
// main for opt
//
int main(int argc, char **argv) {
  sys::PrintStackTraceOnErrorSignal();
  llvm::PrettyStackTraceProgram X(argc, argv);

  // Enable debug stream buffering.
  EnableDebugBuffering = true;

  llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
  LLVMContext Context;

  InitializeAllTargets();
  InitializeAllTargetMCs();
  InitializeAllAsmPrinters();

  // Initialize passes
  PassRegistry &Registry = *PassRegistry::getPassRegistry();
  initializeCore(Registry);
  initializeScalarOpts(Registry);
  initializeObjCARCOpts(Registry);
  initializeVectorization(Registry);
  initializeIPO(Registry);
  initializeAnalysis(Registry);
  initializeTransformUtils(Registry);
  initializeInstCombine(Registry);
  initializeInstrumentation(Registry);
  initializeTarget(Registry);
  // For codegen passes, only passes that do IR to IR transformation are
  // supported.
  initializeCodeGenPreparePass(Registry);
  initializeAtomicExpandPass(Registry);
  initializeRewriteSymbolsPass(Registry);
  initializeWinEHPreparePass(Registry);
  initializeDwarfEHPreparePass(Registry);
  initializeSafeStackPass(Registry);
  initializeSjLjEHPreparePass(Registry);

#ifdef LINK_POLLY_INTO_TOOLS
  polly::initializePollyPasses(Registry);
#endif

  cl::ParseCommandLineOptions(argc, argv,
    "llvm .bc -> .bc modular optimizer and analysis printer\n");

  if (AnalyzeOnly && NoOutput) {
    errs() << argv[0] << ": analyze mode conflicts with no-output mode.\n";
    return 1;
  }

  SMDiagnostic Err;

  Context.setDiscardValueNames(DiscardValueNames);
  if (!DisableDITypeMap)
    Context.enableDebugTypeODRUniquing();

  // Load the input module...
  std::unique_ptr<Module> M = parseIRFile(InputFilename, Err, Context);

  if (!M) {
    Err.print(argv[0], errs());
    return 1;
  }

  // Strip debug info before running the verifier.
  if (StripDebug)
    StripDebugInfo(*M);

  // Immediately run the verifier to catch any problems before starting up the
  // pass pipelines.  Otherwise we can crash on broken code during
  // doInitialization().
  if (!NoVerify && verifyModule(*M, &errs())) {
    errs() << argv[0] << ": " << InputFilename
           << ": error: input module is broken!\n";
    return 1;
  }

  // If we are supposed to override the target triple, do so now.
  if (!TargetTriple.empty())
    M->setTargetTriple(Triple::normalize(TargetTriple));

  // Figure out what stream we are supposed to write to...
  std::unique_ptr<tool_output_file> Out;
  if (NoOutput) {
    if (!OutputFilename.empty())
      errs() << "WARNING: The -o (output filename) option is ignored when\n"
                "the --disable-output option is used.\n";
  } else {
    // Default to standard output.
    if (OutputFilename.empty())
      OutputFilename = "-";

    std::error_code EC;
    Out.reset(new tool_output_file(OutputFilename, EC, sys::fs::F_None));
    if (EC) {
      errs() << EC.message() << '\n';
      return 1;
    }
  }
//.........这里部分代码省略.........

// Main entry point for the ThinLTO processing
void ThinLTOCodeGenerator::run() {
  if (CodeGenOnly) {
    // Perform only parallel codegen and return.
    ThreadPool Pool;
    assert(ProducedBinaries.empty() && "The generator should not be reused");
    ProducedBinaries.resize(Modules.size());
    int count = 0;
    for (auto &ModuleBuffer : Modules) {
      Pool.async([&](int count) {
        LLVMContext Context;
        Context.setDiscardValueNames(LTODiscardValueNames);

        // Parse module now
        auto TheModule = loadModuleFromBuffer(ModuleBuffer, Context, false);

        // CodeGen
        ProducedBinaries[count] = codegen(*TheModule);
      }, count++);
    }

    return;
  }

  // Sequential linking phase
  auto Index = linkCombinedIndex();

  // Save temps: index.
  if (!SaveTempsDir.empty()) {
    auto SaveTempPath = SaveTempsDir + "index.bc";
    std::error_code EC;
    raw_fd_ostream OS(SaveTempPath, EC, sys::fs::F_None);
    if (EC)
      report_fatal_error(Twine("Failed to open ") + SaveTempPath +
                         " to save optimized bitcode\n");
    WriteIndexToFile(*Index, OS);
  }

  // Prepare the resulting object vector
  assert(ProducedBinaries.empty() && "The generator should not be reused");
  ProducedBinaries.resize(Modules.size());

  // Prepare the module map.
  auto ModuleMap = generateModuleMap(Modules);
  auto ModuleCount = Modules.size();

  // Collect for each module the list of function it defines (GUID -> Summary).
  StringMap<GVSummaryMapTy> ModuleToDefinedGVSummaries(ModuleCount);
  Index->collectDefinedGVSummariesPerModule(ModuleToDefinedGVSummaries);

  // Collect the import/export lists for all modules from the call-graph in the
  // combined index.
  StringMap<FunctionImporter::ImportMapTy> ImportLists(ModuleCount);
  StringMap<FunctionImporter::ExportSetTy> ExportLists(ModuleCount);
  ComputeCrossModuleImport(*Index, ModuleToDefinedGVSummaries, ImportLists,
                           ExportLists);

  // Convert the preserved symbols set from string to GUID, this is needed for
  // computing the caching hash and the internalization.
  auto GUIDPreservedSymbols =
      computeGUIDPreservedSymbols(PreservedSymbols, TMBuilder.TheTriple);

  // We use a std::map here to be able to have a defined ordering when
  // producing a hash for the cache entry.
  // FIXME: we should be able to compute the caching hash for the entry based
  // on the index, and nuke this map.
  StringMap<std::map<GlobalValue::GUID, GlobalValue::LinkageTypes>> ResolvedODR;

  // Resolve LinkOnce/Weak symbols, this has to be computed early because it
  // impacts the caching.
  resolveWeakForLinkerInIndex(*Index, ResolvedODR);

  auto isExported = [&](StringRef ModuleIdentifier, GlobalValue::GUID GUID) {
    const auto &ExportList = ExportLists.find(ModuleIdentifier);
    return (ExportList != ExportLists.end() &&
            ExportList->second.count(GUID)) ||
           GUIDPreservedSymbols.count(GUID);
  };

  // Use global summary-based analysis to identify symbols that can be
  // internalized (because they aren't exported or preserved as per callback).
  // Changes are made in the index, consumed in the ThinLTO backends.
  thinLTOInternalizeAndPromoteInIndex(*Index, isExported);

  // Make sure that every module has an entry in the ExportLists and
  // ResolvedODR maps to enable threaded access to these maps below.
  for (auto &DefinedGVSummaries : ModuleToDefinedGVSummaries) {
    ExportLists[DefinedGVSummaries.first()];
    ResolvedODR[DefinedGVSummaries.first()];
  }

  // Compute the ordering we will process the inputs: the rough heuristic here
  // is to sort them per size so that the largest module get schedule as soon as
  // possible. This is purely a compile-time optimization.
  std::vector<int> ModulesOrdering;
  ModulesOrdering.resize(Modules.size());
  std::iota(ModulesOrdering.begin(), ModulesOrdering.end(), 0);
  std::sort(ModulesOrdering.begin(), ModulesOrdering.end(),
            [&](int LeftIndex, int RightIndex) {
              auto LSize = Modules[LeftIndex].getBufferSize();
//.........这里部分代码省略.........

// Main entry point for the ThinLTO processing
void ThinLTOCodeGenerator::run() {
  if (CodeGenOnly) {
    // Perform only parallel codegen and return.
    ThreadPool Pool;
    assert(ProducedBinaries.empty() && "The generator should not be reused");
    ProducedBinaries.resize(Modules.size());
    int count = 0;
    for (auto &ModuleBuffer : Modules) {
      Pool.async([&](int count) {
        LLVMContext Context;
        Context.setDiscardValueNames(LTODiscardValueNames);

        // Parse module now
        auto TheModule = loadModuleFromBuffer(ModuleBuffer, Context, false);

        // CodeGen
        ProducedBinaries[count] = codegen(*TheModule);
      }, count++);
    }

    return;
  }

  // Sequential linking phase
  auto Index = linkCombinedIndex();

  // Save temps: index.
  if (!SaveTempsDir.empty()) {
    auto SaveTempPath = SaveTempsDir + "index.bc";
    std::error_code EC;
    raw_fd_ostream OS(SaveTempPath, EC, sys::fs::F_None);
    if (EC)
      report_fatal_error(Twine("Failed to open ") + SaveTempPath +
                         " to save optimized bitcode\n");
    WriteIndexToFile(*Index, OS);
  }

  // Prepare the resulting object vector
  assert(ProducedBinaries.empty() && "The generator should not be reused");
  ProducedBinaries.resize(Modules.size());

  // Prepare the module map.
  auto ModuleMap = generateModuleMap(Modules);
  auto ModuleCount = Modules.size();

  // Collect the import/export lists for all modules from the call-graph in the
  // combined index.
  StringMap<FunctionImporter::ImportMapTy> ImportLists(ModuleCount);
  StringMap<FunctionImporter::ExportSetTy> ExportLists(ModuleCount);
  ComputeCrossModuleImport(*Index, ImportLists, ExportLists);

  // Parallel optimizer + codegen
  {
    ThreadPool Pool(ThreadCount);
    int count = 0;
    for (auto &ModuleBuffer : Modules) {
      Pool.async([&](int count) {
        LLVMContext Context;
        Context.setDiscardValueNames(LTODiscardValueNames);

        // Parse module now
        auto TheModule = loadModuleFromBuffer(ModuleBuffer, Context, false);

        // Save temps: original file.
        if (!SaveTempsDir.empty()) {
          saveTempBitcode(*TheModule, SaveTempsDir, count, ".0.original.bc");
        }

        auto &ImportList = ImportLists[TheModule->getModuleIdentifier()];
        ProducedBinaries[count] = ProcessThinLTOModule(
            *TheModule, *Index, ModuleMap, *TMBuilder.create(), ImportList,
            CacheOptions, DisableCodeGen, SaveTempsDir, count);
      }, count);
      count++;
    }
  }

  // If statistics were requested, print them out now.
  if (llvm::AreStatisticsEnabled())
    llvm::PrintStatistics();
}