C++ SubtargetFeatures::setCPU方法代码示例

/// selectTarget - Pick a target either via -march or by guessing the native
/// arch.  Add any CPU features specified via -mcpu or -mattr.
TargetMachine *MCJIT::selectTarget(Module *Mod,
                                 StringRef MArch,
                                 StringRef MCPU,
                                 const SmallVectorImpl<std::string>& MAttrs,
                                 std::string *ErrorStr) {
  Triple TheTriple(Mod->getTargetTriple());
  if (TheTriple.getTriple().empty())
    TheTriple.setTriple(sys::getHostTriple());

  // Adjust the triple to match what the user requested.
  const Target *TheTarget = 0;
  if (!MArch.empty()) {
    for (TargetRegistry::iterator it = TargetRegistry::begin(),
           ie = TargetRegistry::end(); it != ie; ++it) {
      if (MArch == it->getName()) {
        TheTarget = &*it;
        break;
      }
    }

    if (!TheTarget) {
      *ErrorStr = "No available targets are compatible with this -march, "
        "see -version for the available targets.\n";
      return 0;
    }

    // Adjust the triple to match (if known), otherwise stick with the
    // module/host triple.
    Triple::ArchType Type = Triple::getArchTypeForLLVMName(MArch);
    if (Type != Triple::UnknownArch)
      TheTriple.setArch(Type);
  } else {
    std::string Error;
    TheTarget = TargetRegistry::lookupTarget(TheTriple.getTriple(), Error);
    if (TheTarget == 0) {
      if (ErrorStr)
        *ErrorStr = Error;
      return 0;
    }
  }

  if (!TheTarget->hasJIT()) {
    errs() << "WARNING: This target JIT is not designed for the host you are"
           << " running.  If bad things happen, please choose a different "
           << "-march switch.\n";
  }

  // Package up features to be passed to target/subtarget
  std::string FeaturesStr;
  if (!MCPU.empty() || !MAttrs.empty()) {
    SubtargetFeatures Features;
    Features.setCPU(MCPU);
    for (unsigned i = 0; i != MAttrs.size(); ++i)
      Features.AddFeature(MAttrs[i]);
    FeaturesStr = Features.getString();
  }

  // Allocate a target...
  TargetMachine *Target =
    TheTarget->createTargetMachine(TheTriple.getTriple(), FeaturesStr);
  assert(Target && "Could not allocate target machine!");
  return Target;
}

// main - Entry point for the llc compiler.
//
int main(int argc, char **argv) {
  llvm_shutdown_obj X;  // Call llvm_shutdown() on exit.
  cl::ParseCommandLineOptions(argc, argv, "llvm system compiler\n");
  sys::PrintStackTraceOnErrorSignal();

  // Load the module to be compiled...
  std::string ErrorMessage;
  std::auto_ptr<Module> M;
  
  std::auto_ptr<MemoryBuffer> Buffer(
                   MemoryBuffer::getFileOrSTDIN(InputFilename, &ErrorMessage));
  if (Buffer.get())
    M.reset(ParseBitcodeFile(Buffer.get(), &ErrorMessage));
  if (M.get() == 0) {
    std::cerr << argv[0] << ": bitcode didn't read correctly.\n";
    std::cerr << "Reason: " << ErrorMessage << "\n";
    return 1;
  }
  Module &mod = *M.get();
  
  // If we are supposed to override the target triple, do so now.
  if (!TargetTriple.empty())
    mod.setTargetTriple(TargetTriple);
  
  // Allocate target machine.  First, check whether the user has
  // explicitly specified an architecture to compile for.
  if (MArch == 0) {
    std::string Err;
    MArch = TargetMachineRegistry::getClosestStaticTargetForModule(mod, Err);
    if (MArch == 0) {
      std::cerr << argv[0] << ": error auto-selecting target for module '"
                << Err << "'.  Please use the -march option to explicitly "
                << "pick a target.\n";
      return 1;
    }
  }

  // Package up features to be passed to target/subtarget
  std::string FeaturesStr;
  if (MCPU.size() || MAttrs.size()) {
    SubtargetFeatures Features;
    Features.setCPU(MCPU);
    for (unsigned i = 0; i != MAttrs.size(); ++i)
      Features.AddFeature(MAttrs[i]);
    FeaturesStr = Features.getString();
  }
  
  std::auto_ptr<TargetMachine> target(MArch->CtorFn(mod, FeaturesStr));
  assert(target.get() && "Could not allocate target machine!");
  TargetMachine &Target = *target.get();

  // Figure out where we are going to send the output...
  std::ostream *Out = GetOutputStream(argv[0]);
  if (Out == 0) return 1;
  
  // If this target requires addPassesToEmitWholeFile, do it now.  This is
  // used by strange things like the C backend.
  if (Target.WantsWholeFile()) {
    PassManager PM;
    PM.add(new TargetData(*Target.getTargetData()));
    if (!NoVerify)
      PM.add(createVerifierPass());
    
    // Ask the target to add backend passes as necessary.
    if (Target.addPassesToEmitWholeFile(PM, *Out, FileType, Fast)) {
      std::cerr << argv[0] << ": target does not support generation of this"
                << " file type!\n";
      if (Out != &std::cout) delete Out;
      // And the Out file is empty and useless, so remove it now.
      sys::Path(OutputFilename).eraseFromDisk();
      return 1;
    }
    PM.run(mod);
  } else {
    // Build up all of the passes that we want to do to the module.
    ExistingModuleProvider Provider(M.release());
    FunctionPassManager Passes(&Provider);
    Passes.add(new TargetData(*Target.getTargetData()));
    
#ifndef NDEBUG
    if (!NoVerify)
      Passes.add(createVerifierPass());
#endif
  
    // Ask the target to add backend passes as necessary.
    MachineCodeEmitter *MCE = 0;

    switch (Target.addPassesToEmitFile(Passes, *Out, FileType, Fast)) {
    default:
      assert(0 && "Invalid file model!");
      return 1;
    case FileModel::Error:
      std::cerr << argv[0] << ": target does not support generation of this"
                << " file type!\n";
      if (Out != &std::cout) delete Out;
      // And the Out file is empty and useless, so remove it now.
      sys::Path(OutputFilename).eraseFromDisk();
      return 1;
//.........这里部分代码省略.........

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

  // Enable debug stream buffering.
  EnableDebugBuffering = true;

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

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

  cl::ParseCommandLineOptions(argc, argv, "llvm system compiler\n");
  
  // Load the module to be compiled...
  SMDiagnostic Err;
  std::auto_ptr<Module> M;

  M.reset(ParseIRFile(InputFilename, Err, Context));
  if (M.get() == 0) {
    Err.Print(argv[0], errs());
    return 1;
  }
  Module &mod = *M.get();

  // If we are supposed to override the target triple, do so now.
  if (!TargetTriple.empty())
    mod.setTargetTriple(TargetTriple);

  Triple TheTriple(mod.getTargetTriple());
  if (TheTriple.getTriple().empty())
    TheTriple.setTriple(sys::getHostTriple());

  // Allocate target machine.  First, check whether the user has explicitly
  // specified an architecture to compile for. If so we have to look it up by
  // name, because it might be a backend that has no mapping to a target triple.
  const Target *TheTarget = 0;
  if (!MArch.empty()) {
    for (TargetRegistry::iterator it = TargetRegistry::begin(),
           ie = TargetRegistry::end(); it != ie; ++it) {
      if (MArch == it->getName()) {
        TheTarget = &*it;
        break;
      }
    }

    if (!TheTarget) {
      errs() << argv[0] << ": error: invalid target '" << MArch << "'.\n";
      return 1;
    }

    // Adjust the triple to match (if known), otherwise stick with the
    // module/host triple.
    Triple::ArchType Type = Triple::getArchTypeForLLVMName(MArch);
    if (Type != Triple::UnknownArch)
      TheTriple.setArch(Type);
  } else {
    std::string Err;
    TheTarget = TargetRegistry::lookupTarget(TheTriple.getTriple(), Err);
    if (TheTarget == 0) {
      errs() << argv[0] << ": error auto-selecting target for module '"
             << Err << "'.  Please use the -march option to explicitly "
             << "pick a target.\n";
      return 1;
    }
  }

  // Package up features to be passed to target/subtarget
  std::string FeaturesStr;
  if (MCPU.size() || MAttrs.size()) {
    SubtargetFeatures Features;
    Features.setCPU(MCPU);
    for (unsigned i = 0; i != MAttrs.size(); ++i)
      Features.AddFeature(MAttrs[i]);
    FeaturesStr = Features.getString();
  }

  std::auto_ptr<TargetMachine> 
    target(TheTarget->createTargetMachine(TheTriple.getTriple(), FeaturesStr));
  assert(target.get() && "Could not allocate target machine!");
  TargetMachine &Target = *target.get();

  // Figure out where we are going to send the output...
  formatted_raw_ostream *Out = GetOutputStream(TheTarget->getName(), argv[0]);
  if (Out == 0) return 1;

  CodeGenOpt::Level OLvl = CodeGenOpt::Default;
  switch (OptLevel) {
  default:
    errs() << argv[0] << ": invalid optimization level.\n";
    return 1;
  case ' ': break;
  case '0': OLvl = CodeGenOpt::None; break;
  case '1': OLvl = CodeGenOpt::Less; break;
  case '2': OLvl = CodeGenOpt::Default; break;
  case '3': OLvl = CodeGenOpt::Aggressive; break;
//.........这里部分代码省略.........

bool BackendConsumer::AddEmitPasses() {
  if (Action == Backend_EmitNothing)
    return true;

  if (Action == Backend_EmitBC) {
    getPerModulePasses()->add(createBitcodeWriterPass(FormattedOutStream));
  } else if (Action == Backend_EmitLL) {
    getPerModulePasses()->add(createPrintModulePass(&FormattedOutStream));
  } else {
    bool Fast = CodeGenOpts.OptimizationLevel == 0;

    // Create the TargetMachine for generating code.
    std::string Error;
    std::string Triple = TheModule->getTargetTriple();
    const llvm::Target *TheTarget = TargetRegistry::lookupTarget(Triple, Error);
    if (!TheTarget) {
      Diags.Report(diag::err_fe_unable_to_create_target) << Error;
      return false;
    }

    // FIXME: Expose these capabilities via actual APIs!!!! Aside from just
    // being gross, this is also totally broken if we ever care about
    // concurrency.
    llvm::NoFramePointerElim = CodeGenOpts.DisableFPElim;
    if (CodeGenOpts.FloatABI == "soft")
      llvm::FloatABIType = llvm::FloatABI::Soft;
    else if (CodeGenOpts.FloatABI == "hard")
      llvm::FloatABIType = llvm::FloatABI::Hard;
    else {
      assert(CodeGenOpts.FloatABI.empty() && "Invalid float abi!");
      llvm::FloatABIType = llvm::FloatABI::Default;
    }
    NoZerosInBSS = CodeGenOpts.NoZeroInitializedInBSS;
    llvm::UseSoftFloat = CodeGenOpts.SoftFloat;
    UnwindTablesMandatory = CodeGenOpts.UnwindTables;

    TargetMachine::setAsmVerbosityDefault(CodeGenOpts.AsmVerbose);

    // FIXME: Parse this earlier.
    if (CodeGenOpts.RelocationModel == "static") {
      TargetMachine::setRelocationModel(llvm::Reloc::Static);
    } else if (CodeGenOpts.RelocationModel == "pic") {
      TargetMachine::setRelocationModel(llvm::Reloc::PIC_);
    } else {
      assert(CodeGenOpts.RelocationModel == "dynamic-no-pic" &&
             "Invalid PIC model!");
      TargetMachine::setRelocationModel(llvm::Reloc::DynamicNoPIC);
    }
    // FIXME: Parse this earlier.
    if (CodeGenOpts.CodeModel == "small") {
      TargetMachine::setCodeModel(llvm::CodeModel::Small);
    } else if (CodeGenOpts.CodeModel == "kernel") {
      TargetMachine::setCodeModel(llvm::CodeModel::Kernel);
    } else if (CodeGenOpts.CodeModel == "medium") {
      TargetMachine::setCodeModel(llvm::CodeModel::Medium);
    } else if (CodeGenOpts.CodeModel == "large") {
      TargetMachine::setCodeModel(llvm::CodeModel::Large);
    } else {
      assert(CodeGenOpts.CodeModel.empty() && "Invalid code model!");
      TargetMachine::setCodeModel(llvm::CodeModel::Default);
    }

    std::vector<const char *> BackendArgs;
    BackendArgs.push_back("clang"); // Fake program name.
    if (!CodeGenOpts.DebugPass.empty()) {
      BackendArgs.push_back("-debug-pass");
      BackendArgs.push_back(CodeGenOpts.DebugPass.c_str());
    }
    if (!CodeGenOpts.LimitFloatPrecision.empty()) {
      BackendArgs.push_back("-limit-float-precision");
      BackendArgs.push_back(CodeGenOpts.LimitFloatPrecision.c_str());
    }
    if (llvm::TimePassesIsEnabled)
      BackendArgs.push_back("-time-passes");
    BackendArgs.push_back(0);
    llvm::cl::ParseCommandLineOptions(BackendArgs.size() - 1,
                                      (char**) &BackendArgs[0]);

    std::string FeaturesStr;
    if (TargetOpts.CPU.size() || TargetOpts.Features.size()) {
      SubtargetFeatures Features;
      Features.setCPU(TargetOpts.CPU);
      for (std::vector<std::string>::const_iterator
             it = TargetOpts.Features.begin(),
             ie = TargetOpts.Features.end(); it != ie; ++it)
        Features.AddFeature(*it);
      FeaturesStr = Features.getString();
    }
    TargetMachine *TM = TheTarget->createTargetMachine(Triple, FeaturesStr);

    // Set register scheduler & allocation policy.
    RegisterScheduler::setDefault(createDefaultScheduler);
    RegisterRegAlloc::setDefault(Fast ? createLocalRegisterAllocator :
                                 createLinearScanRegisterAllocator);

    // From llvm-gcc:
    // If there are passes we have to run on the entire module, we do codegen
    // as a separate "pass" after that happens.
    // FIXME: This is disabled right now until bugs can be worked out.  Reenable
    // this for fast -O0 compiles!
//.........这里部分代码省略.........