C++ LTOCodeGenerator::setOptLevel方法代码示例

// Convert the subtarget features into a string to pass to LTOCodeGenerator.
static void lto_add_attrs(lto_code_gen_t cg) {
  LTOCodeGenerator *CG = unwrap(cg);
  if (MAttrs.size()) {
    std::string attrs;
    for (unsigned i = 0; i < MAttrs.size(); ++i) {
      if (i > 0)
        attrs.append(",");
      attrs.append(MAttrs[i]);
    }

    CG->setAttr(attrs.c_str());
  }

  if (OptLevel < '0' || OptLevel > '3')
    report_fatal_error("Optimization level must be between 0 and 3");
  CG->setOptLevel(OptLevel - '0');
}

int main(int argc, char **argv) {
  // Print a stack trace if we signal out.
  sys::PrintStackTraceOnErrorSignal();
  PrettyStackTraceProgram X(argc, argv);

  llvm_shutdown_obj Y; // Call llvm_shutdown() on exit.
  cl::ParseCommandLineOptions(argc, argv, "llvm LTO linker\n");

  if (OptLevel < '0' || OptLevel > '3') {
    errs() << argv[0] << ": optimization level must be between 0 and 3\n";
    return 1;
  }

  // Initialize the configured targets.
  InitializeAllTargets();
  InitializeAllTargetMCs();
  InitializeAllAsmPrinters();
  InitializeAllAsmParsers();

  // set up the TargetOptions for the machine
  TargetOptions Options = InitTargetOptionsFromCodeGenFlags();

  if (ListSymbolsOnly)
    return listSymbols(argv[0], Options);

  if (ThinLTO)
    return createCombinedFunctionIndex(argv[0]);

  unsigned BaseArg = 0;

  LTOCodeGenerator CodeGen;

  if (UseDiagnosticHandler)
    CodeGen.setDiagnosticHandler(handleDiagnostics, nullptr);

  CodeGen.setCodePICModel(RelocModel);

  CodeGen.setDebugInfo(LTO_DEBUG_MODEL_DWARF);
  CodeGen.setTargetOptions(Options);

  llvm::StringSet<llvm::MallocAllocator> DSOSymbolsSet;
  for (unsigned i = 0; i < DSOSymbols.size(); ++i)
    DSOSymbolsSet.insert(DSOSymbols[i]);

  std::vector<std::string> KeptDSOSyms;

  for (unsigned i = BaseArg; i < InputFilenames.size(); ++i) {
    std::string error;
    std::unique_ptr<LTOModule> Module(
        LTOModule::createFromFile(InputFilenames[i].c_str(), Options, error));
    if (!error.empty()) {
      errs() << argv[0] << ": error loading file '" << InputFilenames[i]
             << "': " << error << "\n";
      return 1;
    }

    unsigned NumSyms = Module->getSymbolCount();
    for (unsigned I = 0; I < NumSyms; ++I) {
      StringRef Name = Module->getSymbolName(I);
      if (!DSOSymbolsSet.count(Name))
        continue;
      lto_symbol_attributes Attrs = Module->getSymbolAttributes(I);
      unsigned Scope = Attrs & LTO_SYMBOL_SCOPE_MASK;
      if (Scope != LTO_SYMBOL_SCOPE_DEFAULT_CAN_BE_HIDDEN)
        KeptDSOSyms.push_back(Name);
    }

    // We use the first input module as the destination module when
    // SetMergedModule is true.
    if (SetMergedModule && i == BaseArg) {
      // Transfer ownership to the code generator.
      CodeGen.setModule(std::move(Module));
    } else if (!CodeGen.addModule(Module.get())) {
      // Print a message here so that we know addModule() did not abort.
      errs() << argv[0] << ": error adding file '" << InputFilenames[i] << "'\n";
      return 1;
    }
  }

  // Add all the exported symbols to the table of symbols to preserve.
  for (unsigned i = 0; i < ExportedSymbols.size(); ++i)
    CodeGen.addMustPreserveSymbol(ExportedSymbols[i].c_str());

  // Add all the dso symbols to the table of symbols to expose.
  for (unsigned i = 0; i < KeptDSOSyms.size(); ++i)
    CodeGen.addMustPreserveSymbol(KeptDSOSyms[i].c_str());

  // Set cpu and attrs strings for the default target/subtarget.
  CodeGen.setCpu(MCPU.c_str());

  CodeGen.setOptLevel(OptLevel - '0');

  std::string attrs;
  for (unsigned i = 0; i < MAttrs.size(); ++i) {
    if (i > 0)
      attrs.append(",");
    attrs.append(MAttrs[i]);
  }

  if (!attrs.empty())
//.........这里部分代码省略.........

//.........这里部分代码省略.........
    llvm::StringSet<llvm::MallocAllocator> DSOSymbolsSet;
    for (unsigned i = 0; i < DSOSymbols.size(); ++i)
        DSOSymbolsSet.insert(DSOSymbols[i]);

    std::vector<std::string> KeptDSOSyms;

    for (unsigned i = BaseArg; i < InputFilenames.size(); ++i) {
        std::string error;
        std::unique_ptr<LTOModule> Module(
            LTOModule::createFromFile(InputFilenames[i].c_str(), Options, error));
        if (!error.empty()) {
            errs() << argv[0] << ": error loading file '" << InputFilenames[i]
                   << "': " << error << "\n";
            return 1;
        }

        LTOModule *LTOMod = Module.get();

        // We use the first input module as the destination module when
        // SetMergedModule is true.
        if (SetMergedModule && i == BaseArg) {
            // Transfer ownership to the code generator.
            CodeGen.setModule(Module.release());
        } else if (!CodeGen.addModule(Module.get())) {
            // Print a message here so that we know addModule() did not abort.
            errs() << argv[0] << ": error adding file '" << InputFilenames[i] << "'\n";
            return 1;
        }

        unsigned NumSyms = LTOMod->getSymbolCount();
        for (unsigned I = 0; I < NumSyms; ++I) {
            StringRef Name = LTOMod->getSymbolName(I);
            if (!DSOSymbolsSet.count(Name))
                continue;
            lto_symbol_attributes Attrs = LTOMod->getSymbolAttributes(I);
            unsigned Scope = Attrs & LTO_SYMBOL_SCOPE_MASK;
            if (Scope != LTO_SYMBOL_SCOPE_DEFAULT_CAN_BE_HIDDEN)
                KeptDSOSyms.push_back(Name);
        }
    }

    // Add all the exported symbols to the table of symbols to preserve.
    for (unsigned i = 0; i < ExportedSymbols.size(); ++i)
        CodeGen.addMustPreserveSymbol(ExportedSymbols[i].c_str());

    // Add all the dso symbols to the table of symbols to expose.
    for (unsigned i = 0; i < KeptDSOSyms.size(); ++i)
        CodeGen.addMustPreserveSymbol(KeptDSOSyms[i].c_str());

    // Set cpu and attrs strings for the default target/subtarget.
    CodeGen.setCpu(MCPU.c_str());

    CodeGen.setOptLevel(OptLevel - '0');

    std::string attrs;
    for (unsigned i = 0; i < MAttrs.size(); ++i) {
        if (i > 0)
            attrs.append(",");
        attrs.append(MAttrs[i]);
    }

    if (!attrs.empty())
        CodeGen.setAttr(attrs.c_str());

    if (!OutputFilename.empty()) {
        std::string ErrorInfo;
        std::unique_ptr<MemoryBuffer> Code = CodeGen.compile(
                DisableInline, DisableGVNLoadPRE, DisableLTOVectorization, ErrorInfo);
        if (!Code) {
            errs() << argv[0]
                   << ": error compiling the code: " << ErrorInfo << "\n";
            return 1;
        }

        std::error_code EC;
        raw_fd_ostream FileStream(OutputFilename, EC, sys::fs::F_None);
        if (EC) {
            errs() << argv[0] << ": error opening the file '" << OutputFilename
                   << "': " << EC.message() << "\n";
            return 1;
        }

        FileStream.write(Code->getBufferStart(), Code->getBufferSize());
    } else {
        std::string ErrorInfo;
        const char *OutputName = nullptr;
        if (!CodeGen.compile_to_file(&OutputName, DisableInline,
                                     DisableGVNLoadPRE, DisableLTOVectorization,
                                     ErrorInfo)) {
            errs() << argv[0]
                   << ": error compiling the code: " << ErrorInfo
                   << "\n";
            return 1;
        }

        outs() << "Wrote native object file '" << OutputName << "'\n";
    }

    return 0;
}