C++ opt::getPosition方法代码示例

HexagonSubtarget &
HexagonSubtarget::initializeSubtargetDependencies(StringRef CPU, StringRef FS) {
  CPUString = HEXAGON_MC::selectHexagonCPU(getTargetTriple(), CPU);

  static std::map<StringRef, HexagonArchEnum> CpuTable {
    { "hexagonv4", V4 },
    { "hexagonv5", V5 },
    { "hexagonv55", V55 },
    { "hexagonv60", V60 },
  };

  auto foundIt = CpuTable.find(CPUString);
  if (foundIt != CpuTable.end())
    HexagonArchVersion = foundIt->second;
  else
    llvm_unreachable("Unrecognized Hexagon processor version");

  UseHVXOps = false;
  UseHVXDblOps = false;
  UseLongCalls = false;
  ParseSubtargetFeatures(CPUString, FS);

  if (EnableHexagonHVX.getPosition())
    UseHVXOps = EnableHexagonHVX;
  if (EnableHexagonHVXDouble.getPosition())
    UseHVXDblOps = EnableHexagonHVXDouble;
  if (OverrideLongCalls.getPosition())
    UseLongCalls = OverrideLongCalls;

  return *this;
}

//////////////////////////////////////////////////////////////////////////////////////////
// This function runs optimization passes based on command line arguments.
// Returns true if any optimization passes were invoked.
bool ldc_optimize_module(llvm::Module* m)
{
    if (!optimize())
        return false;

    PassManager pm;

    if (verifyEach) pm.add(createVerifierPass());

#if LDC_LLVM_VER >= 302
    addPass(pm, new DataLayout(m));
#else
    addPass(pm, new TargetData(m));
#endif

    bool optimize = optimizeLevel != 0 || doInline();

    unsigned optPos = optimizeLevel != 0
                    ? optimizeLevel.getPosition()
                    : enableInlining.getPosition();

    for (size_t i = 0; i < passList.size(); i++) {
        // insert -O<N> / -enable-inlining in right position
        if (optimize && optPos < passList.getPosition(i)) {
            addPassesForOptLevel(pm);
            optimize = false;
        }

        const PassInfo* pass = passList[i];
        if (PassInfo::NormalCtor_t ctor = pass->getNormalCtor()) {
            addPass(pm, ctor());
        } else {
            const char* arg = pass->getPassArgument(); // may return null
            if (arg)
                error("Can't create pass '-%s' (%s)", arg, pass->getPassName());
            else
                error("Can't create pass (%s)", pass->getPassName());
            assert(0);  // Should be unreachable; root.h:error() calls exit()
        }
    }
    // insert -O<N> / -enable-inlining if specified at the end,
    if (optimize)
        addPassesForOptLevel(pm);

    pm.run(*m);

    verifyModule(m);

    return true;
}

bool HexagonGenExtract::visitBlock(BasicBlock *B) {
  // Depth-first, bottom-up traversal.
  for (auto *DTN : children<DomTreeNode*>(DT->getNode(B)))
    visitBlock(DTN->getBlock());

  // Allow limiting the number of generated extracts for debugging purposes.
  bool HasCutoff = ExtractCutoff.getPosition();
  unsigned Cutoff = ExtractCutoff;

  bool Changed = false;
  BasicBlock::iterator I = std::prev(B->end()), NextI, Begin = B->begin();
  while (true) {
    if (HasCutoff && (ExtractCount >= Cutoff))
      return Changed;
    bool Last = (I == Begin);
    if (!Last)
      NextI = std::prev(I);
    Instruction *In = &*I;
    bool Done = convert(In);
    if (HasCutoff && Done)
      ExtractCount++;
    Changed |= Done;
    if (Last)
      break;
    I = NextI;
  }
  return Changed;
}

bool HexagonGenExtract::visitBlock(BasicBlock *B) {
    // Depth-first, bottom-up traversal.
    DomTreeNode *DTN = DT->getNode(B);
    typedef GraphTraits<DomTreeNode*> GTN;
    typedef GTN::ChildIteratorType Iter;
    for (Iter I = GTN::child_begin(DTN), E = GTN::child_end(DTN); I != E; ++I)
        visitBlock((*I)->getBlock());

    // Allow limiting the number of generated extracts for debugging purposes.
    bool HasCutoff = ExtractCutoff.getPosition();
    unsigned Cutoff = ExtractCutoff;

    bool Changed = false;
    BasicBlock::iterator I = std::prev(B->end()), NextI, Begin = B->begin();
    while (true) {
        if (HasCutoff && (ExtractCount >= Cutoff))
            return Changed;
        bool Last = (I == Begin);
        if (!Last)
            NextI = std::prev(I);
        Instruction *In = &*I;
        bool Done = convert(In);
        if (HasCutoff && Done)
            ExtractCount++;
        Changed |= Done;
        if (Last)
            break;
        I = NextI;
    }
    return Changed;
}

/// Implements shrink-wrapping of the stack frame. By default, stack frame
/// is created in the function entry block, and is cleaned up in every block
/// that returns. This function finds alternate blocks: one for the frame
/// setup (prolog) and one for the cleanup (epilog).
void HexagonFrameLowering::findShrunkPrologEpilog(MachineFunction &MF,
      MachineBasicBlock *&PrologB, MachineBasicBlock *&EpilogB) const {
  static unsigned ShrinkCounter = 0;

  if (ShrinkLimit.getPosition()) {
    if (ShrinkCounter >= ShrinkLimit)
      return;
    ShrinkCounter++;
  }

  auto &HST = static_cast<const HexagonSubtarget&>(MF.getSubtarget());
  auto &HRI = *HST.getRegisterInfo();

  MachineDominatorTree MDT;
  MDT.runOnMachineFunction(MF);
  MachinePostDominatorTree MPT;
  MPT.runOnMachineFunction(MF);

  typedef DenseMap<unsigned,unsigned> UnsignedMap;
  UnsignedMap RPO;
  typedef ReversePostOrderTraversal<const MachineFunction*> RPOTType;
  RPOTType RPOT(&MF);
  unsigned RPON = 0;
  for (RPOTType::rpo_iterator I = RPOT.begin(), E = RPOT.end(); I != E; ++I)
    RPO[(*I)->getNumber()] = RPON++;

  // Don't process functions that have loops, at least for now. Placement
  // of prolog and epilog must take loop structure into account. For simpli-
  // city don't do it right now.
  for (auto &I : MF) {
    unsigned BN = RPO[I.getNumber()];
    for (auto SI = I.succ_begin(), SE = I.succ_end(); SI != SE; ++SI) {
      // If found a back-edge, return.
      if (RPO[(*SI)->getNumber()] <= BN)
        return;
    }
  }

  // Collect the set of blocks that need a stack frame to execute. Scan
  // each block for uses/defs of callee-saved registers, calls, etc.
  SmallVector<MachineBasicBlock*,16> SFBlocks;
  BitVector CSR(Hexagon::NUM_TARGET_REGS);
  for (const MCPhysReg *P = HRI.getCalleeSavedRegs(&MF); *P; ++P)
    CSR[*P] = true;

  for (auto &I : MF)
    if (needsStackFrame(I, CSR))
      SFBlocks.push_back(&I);

  DEBUG({
    dbgs() << "Blocks needing SF: {";
    for (auto &B : SFBlocks)
      dbgs() << " BB#" << B->getNumber();
    dbgs() << " }\n";
  });

static void processViewOptions() {
  if (!EnableAllViews.getNumOccurrences() &&
      !EnableAllStats.getNumOccurrences())
    return;

  if (EnableAllViews.getNumOccurrences()) {
    processOptionImpl(PrintSummaryView, EnableAllViews);
    processOptionImpl(PrintResourcePressureView, EnableAllViews);
    processOptionImpl(PrintTimelineView, EnableAllViews);
    processOptionImpl(PrintInstructionInfoView, EnableAllViews);
  }

  const cl::opt<bool> &Default =
      EnableAllViews.getPosition() < EnableAllStats.getPosition()
          ? EnableAllStats
          : EnableAllViews;
  processOptionImpl(PrintRegisterFileStats, Default);
  processOptionImpl(PrintDispatchStats, Default);
  processOptionImpl(PrintSchedulerStats, Default);
  processOptionImpl(PrintRetireStats, Default);
}

static void processOptionImpl(cl::opt<bool> &O, const cl::opt<bool> &Default) {
  if (!O.getNumOccurrences() || O.getPosition() < Default.getPosition())
    O = Default.getValue();
}

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

  if (AnalyzeOnly && NoOutput) {
    errs() << argv[0] << ": analyze mode conflicts with no-output mode.\n";
    return 1;
  }
  
  // Enable debug stream buffering.
  EnableDebugBuffering = true;

  llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
  LLVMContext &Context = getGlobalContext();
  
  cl::ParseCommandLineOptions(argc, argv,
    "llvm .bc -> .bc modular optimizer and analysis printer\n");

  // Allocate a full target machine description only if necessary.
  // FIXME: The choice of target should be controllable on the command line.
  std::auto_ptr<TargetMachine> target;

  SMDiagnostic Err;

  // Load the input module...
  std::auto_ptr<Module> M;
  M.reset(ParseIRFile(InputFilename, Err, Context));

  if (M.get() == 0) {
    Err.Print(argv[0], errs());
    return 1;
  }

  // Figure out what stream we are supposed to write to...
  OwningPtr<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::string ErrorInfo;
    Out.reset(new tool_output_file(OutputFilename.c_str(), ErrorInfo,
                                   raw_fd_ostream::F_Binary));
    if (!ErrorInfo.empty()) {
      errs() << ErrorInfo << '\n';
      return 1;
    }
  }

  // If the output is set to be emitted to standard out, and standard out is a
  // console, print out a warning message and refuse to do it.  We don't
  // impress anyone by spewing tons of binary goo to a terminal.
  if (!Force && !NoOutput && !AnalyzeOnly && !OutputAssembly)
    if (CheckBitcodeOutputToConsole(Out->os(), !Quiet))
      NoOutput = true;

  // Create a PassManager to hold and optimize the collection of passes we are
  // about to build...
  //
  PassManager Passes;

  // Add an appropriate TargetData instance for this module...
  TargetData *TD = 0;
  const std::string &ModuleDataLayout = M.get()->getDataLayout();
  if (!ModuleDataLayout.empty())
    TD = new TargetData(ModuleDataLayout);
  else if (!DefaultDataLayout.empty())
    TD = new TargetData(DefaultDataLayout);

  if (TD)
    Passes.add(TD);

  OwningPtr<PassManager> FPasses;
  if (OptLevelO1 || OptLevelO2 || OptLevelO3) {
    FPasses.reset(new PassManager());
    if (TD)
      FPasses->add(new TargetData(*TD));
  }

  // If the -strip-debug command line option was specified, add it.  If
  // -std-compile-opts was also specified, it will handle StripDebug.
  if (StripDebug && !StandardCompileOpts)
    addPass(Passes, createStripSymbolsPass(true));

  // Create a new optimization pass for each one specified on the command line
  for (unsigned i = 0; i < PassList.size(); ++i) {
    // Check to see if -std-compile-opts was specified before this option.  If
    // so, handle it.
    if (StandardCompileOpts &&
        StandardCompileOpts.getPosition() < PassList.getPosition(i)) {
      AddStandardCompilePasses(Passes);
      StandardCompileOpts = false;
    }
//.........这里部分代码省略.........

ARMSubtarget::ARMSubtarget(const std::string &TT, const std::string &FS,
                           bool isT)
    : ARMArchVersion(V4T)
    , ARMFPUType(None)
    , UseNEONForSinglePrecisionFP(UseNEONFP)
    , IsThumb(isT)
    , ThumbMode(Thumb1)
    , PostRAScheduler(false)
    , IsR9Reserved(ReserveR9)
    , UseMovt(UseMOVT)
    , stackAlignment(4)
    , CPUString("generic")
    , TargetType(isELF) // Default to ELF unless otherwise specified.
    , TargetABI(ARM_ABI_APCS) {
    // default to soft float ABI
    if (FloatABIType == FloatABI::Default)
        FloatABIType = FloatABI::Soft;

    // Determine default and user specified characteristics

    // Parse features string.
    CPUString = ParseSubtargetFeatures(FS, CPUString);

    // Set the boolean corresponding to the current target triple, or the default
    // if one cannot be determined, to true.
    unsigned Len = TT.length();
    unsigned Idx = 0;

    if (Len >= 5 && TT.substr(0, 4) == "armv")
        Idx = 4;
    else if (Len >= 6 && TT.substr(0, 5) == "thumb") {
        IsThumb = true;
        if (Len >= 7 && TT[5] == 'v')
            Idx = 6;
    }
    if (Idx) {
        unsigned SubVer = TT[Idx];
        if (SubVer > '4' && SubVer <= '9') {
            if (SubVer >= '7') {
                ARMArchVersion = V7A;
            } else if (SubVer == '6') {
                ARMArchVersion = V6;
                if (Len >= Idx+3 && TT[Idx+1] == 't' && TT[Idx+2] == '2')
                    ARMArchVersion = V6T2;
            } else if (SubVer == '5') {
                ARMArchVersion = V5T;
                if (Len >= Idx+3 && TT[Idx+1] == 't' && TT[Idx+2] == 'e')
                    ARMArchVersion = V5TE;
            }
            if (ARMArchVersion >= V6T2)
                ThumbMode = Thumb2;
        }
    }

    // Thumb2 implies at least V6T2.
    if (ARMArchVersion < V6T2 && ThumbMode >= Thumb2)
        ARMArchVersion = V6T2;

    if (Len >= 10) {
        if (TT.find("-darwin") != std::string::npos)
            // arm-darwin
            TargetType = isDarwin;
    }

    if (TT.find("eabi") != std::string::npos)
        TargetABI = ARM_ABI_AAPCS;

    if (isAAPCS_ABI())
        stackAlignment = 8;

    if (isTargetDarwin())
        IsR9Reserved = ReserveR9 | (ARMArchVersion < V6);

    if (!isThumb() || hasThumb2())
        PostRAScheduler = true;

    // Set CPU specific features.
    if (CPUString == "cortex-a8") {
        // On Cortex-a8, it's faster to perform some single-precision FP
        // operations with NEON instructions.
        if (UseNEONFP.getPosition() == 0)
            UseNEONForSinglePrecisionFP = true;
    }
}

//.........这里部分代码省略.........

  // Add internal analysis passes from the target machine.
  Passes.add(createTargetTransformInfoWrapperPass(TM ? TM->getTargetIRAnalysis()
                                                     : TargetIRAnalysis()));

  std::unique_ptr<legacy::FunctionPassManager> FPasses;
  if (OptLevelO1 || OptLevelO2 || OptLevelOs || OptLevelOz || OptLevelO3) {
    FPasses.reset(new legacy::FunctionPassManager(M.get()));
    FPasses->add(createTargetTransformInfoWrapperPass(
        TM ? TM->getTargetIRAnalysis() : TargetIRAnalysis()));
  }

  if (PrintBreakpoints) {
    // Default to standard output.
    if (!Out) {
      if (OutputFilename.empty())
        OutputFilename = "-";

      std::error_code EC;
      Out = llvm::make_unique<tool_output_file>(OutputFilename, EC,
                                                sys::fs::F_None);
      if (EC) {
        errs() << EC.message() << '\n';
        return 1;
      }
    }
    Passes.add(createBreakpointPrinter(Out->os()));
    NoOutput = true;
  }

  // Create a new optimization pass for each one specified on the command line
  for (unsigned i = 0; i < PassList.size(); ++i) {
    if (StandardLinkOpts &&
        StandardLinkOpts.getPosition() < PassList.getPosition(i)) {
      AddStandardLinkPasses(Passes);
      StandardLinkOpts = false;
    }

    if (OptLevelO1 && OptLevelO1.getPosition() < PassList.getPosition(i)) {
      AddOptimizationPasses(Passes, *FPasses, 1, 0);
      OptLevelO1 = false;
    }

    if (OptLevelO2 && OptLevelO2.getPosition() < PassList.getPosition(i)) {
      AddOptimizationPasses(Passes, *FPasses, 2, 0);
      OptLevelO2 = false;
    }

    if (OptLevelOs && OptLevelOs.getPosition() < PassList.getPosition(i)) {
      AddOptimizationPasses(Passes, *FPasses, 2, 1);
      OptLevelOs = false;
    }

    if (OptLevelOz && OptLevelOz.getPosition() < PassList.getPosition(i)) {
      AddOptimizationPasses(Passes, *FPasses, 2, 2);
      OptLevelOz = false;
    }

    if (OptLevelO3 && OptLevelO3.getPosition() < PassList.getPosition(i)) {
      AddOptimizationPasses(Passes, *FPasses, 3, 0);
      OptLevelO3 = false;
    }

    const PassInfo *PassInf = PassList[i];
    Pass *P = nullptr;
    if (PassInf->getTargetMachineCtor())

//===----------------------------------------------------------------------===//
// main for opt
//
int main(int argc, char **argv) {
    llvm_shutdown_obj X;  // Call llvm_shutdown() on exit.
    try {
        cl::ParseCommandLineOptions(argc, argv,
                                    "llvm .bc -> .bc modular optimizer and analysis printer\n");
        sys::PrintStackTraceOnErrorSignal();

        // Allocate a full target machine description only if necessary.
        // FIXME: The choice of target should be controllable on the command line.
        std::auto_ptr<TargetMachine> target;

        std::string ErrorMessage;

        // Load the input module...
        std::auto_ptr<Module> M;
        if (MemoryBuffer *Buffer
                = MemoryBuffer::getFileOrSTDIN(InputFilename, &ErrorMessage)) {
            M.reset(ParseBitcodeFile(Buffer, &ErrorMessage));
            delete Buffer;
        }

        if (M.get() == 0) {
            cerr << argv[0] << ": ";
            if (ErrorMessage.size())
                cerr << ErrorMessage << "\n";
            else
                cerr << "bitcode didn't read correctly.\n";
            return 1;
        }

        // Figure out what stream we are supposed to write to...
        // FIXME: cout is not binary!
        std::ostream *Out = &std::cout;  // Default to printing to stdout...
        if (OutputFilename != "-") {
            if (!Force && std::ifstream(OutputFilename.c_str())) {
                // If force is not specified, make sure not to overwrite a file!
                cerr << argv[0] << ": error opening '" << OutputFilename
                     << "': file exists!\n"
                     << "Use -f command line argument to force output\n";
                return 1;
            }
            std::ios::openmode io_mode = std::ios::out | std::ios::trunc |
                                         std::ios::binary;
            Out = new std::ofstream(OutputFilename.c_str(), io_mode);

            if (!Out->good()) {
                cerr << argv[0] << ": error opening " << OutputFilename << "!\n";
                return 1;
            }

            // Make sure that the Output file gets unlinked from the disk if we get a
            // SIGINT
            sys::RemoveFileOnSignal(sys::Path(OutputFilename));
        }

        // If the output is set to be emitted to standard out, and standard out is a
        // console, print out a warning message and refuse to do it.  We don't
        // impress anyone by spewing tons of binary goo to a terminal.
        if (!Force && !NoOutput && CheckBitcodeOutputToConsole(Out,!Quiet)) {
            NoOutput = true;
        }

        // Create a PassManager to hold and optimize the collection of passes we are
        // about to build...
        //
        PassManager Passes;

        // Add an appropriate TargetData instance for this module...
        Passes.add(new TargetData(M.get()));

        FunctionPassManager *FPasses = NULL;
        if (OptLevelO1 || OptLevelO2 || OptLevelO3) {
            FPasses = new FunctionPassManager(new ExistingModuleProvider(M.get()));
            FPasses->add(new TargetData(M.get()));
        }

        // If the -strip-debug command line option was specified, add it.  If
        // -std-compile-opts was also specified, it will handle StripDebug.
        if (StripDebug && !StandardCompileOpts)
            addPass(Passes, createStripSymbolsPass(true));

        // Create a new optimization pass for each one specified on the command line
        for (unsigned i = 0; i < PassList.size(); ++i) {
            // Check to see if -std-compile-opts was specified before this option.  If
            // so, handle it.
            if (StandardCompileOpts &&
                    StandardCompileOpts.getPosition() < PassList.getPosition(i)) {
                AddStandardCompilePasses(Passes);
                StandardCompileOpts = false;
            }

            if (OptLevelO1 && OptLevelO1.getPosition() < PassList.getPosition(i)) {
                AddOptimizationPasses(Passes, *FPasses, 1);
                OptLevelO1 = false;
            }

            if (OptLevelO2 && OptLevelO2.getPosition() < PassList.getPosition(i)) {
//.........这里部分代码省略.........

//.........这里部分代码省略.........
  // Add internal analysis passes from the target machine.
  Passes.add(createTargetTransformInfoWrapperPass(TM ? TM->getTargetIRAnalysis()
                                                     : TargetIRAnalysis()));

  std::unique_ptr<legacy::FunctionPassManager> FPasses;
  if (OptLevelO1 || OptLevelO2 || OptLevelOs || OptLevelOz || OptLevelO3) {
    FPasses.reset(new legacy::FunctionPassManager(M.get()));
    FPasses->add(createTargetTransformInfoWrapperPass(
        TM ? TM->getTargetIRAnalysis() : TargetIRAnalysis()));
  }

  if (PrintBreakpoints) {
    // Default to standard output.
    if (!Out) {
      if (OutputFilename.empty())
        OutputFilename = "-";

      std::error_code EC;
      Out = llvm::make_unique<tool_output_file>(OutputFilename, EC,
                                                sys::fs::F_None);
      if (EC) {
        errs() << EC.message() << '\n';
        return 1;
      }
    }
    Passes.add(createBreakpointPrinter(Out->os()));
    NoOutput = true;
  }

  // Create a new optimization pass for each one specified on the command line
  for (unsigned i = 0; i < PassList.size(); ++i) {
    // @LOCALMOD-BEGIN
    if (PNaClABISimplifyPreOpt &&
        PNaClABISimplifyPreOpt.getPosition() < PassList.getPosition(i)) {
      PNaClABISimplifyAddPreOptPasses(&ModuleTriple, Passes);
      PNaClABISimplifyPreOpt = false;
    }
    // @LOCALMOD-END

    if (StandardLinkOpts &&
        StandardLinkOpts.getPosition() < PassList.getPosition(i)) {
      AddStandardLinkPasses(Passes);
      StandardLinkOpts = false;
    }

    if (OptLevelO1 && OptLevelO1.getPosition() < PassList.getPosition(i)) {
      AddOptimizationPasses(Passes, *FPasses, 1, 0);
      OptLevelO1 = false;
    }

    if (OptLevelO2 && OptLevelO2.getPosition() < PassList.getPosition(i)) {
      AddOptimizationPasses(Passes, *FPasses, 2, 0);
      OptLevelO2 = false;
    }

    if (OptLevelOs && OptLevelOs.getPosition() < PassList.getPosition(i)) {
      AddOptimizationPasses(Passes, *FPasses, 2, 1);
      OptLevelOs = false;
    }

    if (OptLevelOz && OptLevelOz.getPosition() < PassList.getPosition(i)) {
      AddOptimizationPasses(Passes, *FPasses, 2, 2);
      OptLevelOz = false;
    }

    if (OptLevelO3 && OptLevelO3.getPosition() < PassList.getPosition(i)) {

//////////////////////////////////////////////////////////////////////////////////////////
// This function runs optimization passes based on command line arguments.
// Returns true if any optimization passes were invoked.
bool ldc_optimize_module(llvm::Module* m)
{
    // Create a PassManager to hold and optimize the collection of
    // per-module passes we are about to build.
    PassManager mpm;

    // Add an appropriate TargetLibraryInfo pass for the module's triple.
    TargetLibraryInfo *tli = new TargetLibraryInfo(Triple(m->getTargetTriple()));

    // The -disable-simplify-libcalls flag actually disables all builtin optzns.
    if (disableSimplifyLibCalls)
        tli->disableAllFunctions();
    mpm.add(tli);

    // Add an appropriate TargetData instance for this module.
#if LDC_LLVM_VER >= 302
    mpm.add(new DataLayout(m));
#else
    mpm.add(new TargetData(m));
#endif

    // Also set up a manager for the per-function passes.
    FunctionPassManager fpm(m);
#if LDC_LLVM_VER >= 302
    fpm.add(new DataLayout(m));
#else
    fpm.add(new TargetData(m));
#endif

    // If the -strip-debug command line option was specified, add it before
    // anything else.
    if (stripDebug)
        mpm.add(createStripSymbolsPass(true));

    bool defaultsAdded = false;
    // Create a new optimization pass for each one specified on the command line
    for (unsigned i = 0; i < passList.size(); ++i) {
        if (optimizeLevel && optimizeLevel.getPosition() < passList.getPosition(i)) {
            addOptimizationPasses(mpm, fpm, optLevel(), sizeLevel());
            defaultsAdded = true;
        }

        const PassInfo *passInf = passList[i];
        Pass *pass = 0;
        if (passInf->getNormalCtor())
            pass = passInf->getNormalCtor()();
        else {
            const char* arg = passInf->getPassArgument(); // may return null
            if (arg)
                error("Can't create pass '-%s' (%s)", arg, pass->getPassName());
            else
                error("Can't create pass (%s)", pass->getPassName());
            llvm_unreachable("pass creation failed");
        }
        if (pass) {
            addPass(mpm, pass);
        }
    }

    // Add the default passes for the specified optimization level.
    if (!defaultsAdded)
        addOptimizationPasses(mpm, fpm, optLevel(), sizeLevel());

    // Run per-function passes.
    fpm.doInitialization();
    for (llvm::Module::iterator F = m->begin(), E = m->end(); F != E; ++F)
        fpm.run(*F);
    fpm.doFinalization();

    // Run per-module passes.
    mpm.run(*m);

    // Verify the resulting module.
    verifyModule(m);

    // Report that we run some passes.
    return true;
}

//===----------------------------------------------------------------------===//
// main for opt
//
int main(int argc, char **argv) {
  sys::PrintStackTraceOnErrorSignal();
  llvm::PrettyStackTraceProgram X(argc, argv);
  
  llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
  LLVMContext &Context = getGlobalContext();
  
  cl::ParseCommandLineOptions(argc, argv,
    "llvm .bc -> .bc modular optimizer and analysis printer\n");

  // Allocate a full target machine description only if necessary.
  // FIXME: The choice of target should be controllable on the command line.
  std::auto_ptr<TargetMachine> target;

  SMDiagnostic Err;

  // Load the input module...
  std::auto_ptr<Module> M;
  M.reset(ParseIRFile(InputFilename, Err, Context));

  if (M.get() == 0) {
    Err.Print(argv[0], errs());
    return 1;
  }

  // Figure out what stream we are supposed to write to...
  // FIXME: outs() is not binary!
  raw_ostream *Out = &outs();  // Default to printing to stdout...
  if (OutputFilename != "-") {
    // Make sure that the Output file gets unlinked from the disk if we get a
    // SIGINT
    sys::RemoveFileOnSignal(sys::Path(OutputFilename));

    std::string ErrorInfo;
    Out = new raw_fd_ostream(OutputFilename.c_str(), ErrorInfo,
                             raw_fd_ostream::F_Binary);
    if (!ErrorInfo.empty()) {
      errs() << ErrorInfo << '\n';
      delete Out;
      return 1;
    }
  }

  // If the output is set to be emitted to standard out, and standard out is a
  // console, print out a warning message and refuse to do it.  We don't
  // impress anyone by spewing tons of binary goo to a terminal.
  if (!Force && !NoOutput && !OutputAssembly)
    if (CheckBitcodeOutputToConsole(*Out, !Quiet))
      NoOutput = true;

  // Create a PassManager to hold and optimize the collection of passes we are
  // about to build...
  //
  PassManager Passes;

  // Add an appropriate TargetData instance for this module...
  TargetData *TD = 0;
  const std::string &ModuleDataLayout = M.get()->getDataLayout();
  if (!ModuleDataLayout.empty())
    TD = new TargetData(ModuleDataLayout);
  else if (!DefaultDataLayout.empty())
    TD = new TargetData(DefaultDataLayout);

  if (TD)
    Passes.add(TD);

  FunctionPassManager *FPasses = NULL;
  if (OptLevelO1 || OptLevelO2 || OptLevelO3) {
    FPasses = new FunctionPassManager(new ExistingModuleProvider(M.get()));
    if (TD)
      FPasses->add(new TargetData(*TD));
  }

  // If the -strip-debug command line option was specified, add it.  If
  // -std-compile-opts was also specified, it will handle StripDebug.
  if (StripDebug && !StandardCompileOpts)
    addPass(Passes, createStripSymbolsPass(true));

  // Create a new optimization pass for each one specified on the command line
  for (unsigned i = 0; i < PassList.size(); ++i) {
    // Check to see if -std-compile-opts was specified before this option.  If
    // so, handle it.
    if (StandardCompileOpts &&
        StandardCompileOpts.getPosition() < PassList.getPosition(i)) {
      AddStandardCompilePasses(Passes);
      StandardCompileOpts = false;
    }

    if (StandardLinkOpts &&
        StandardLinkOpts.getPosition() < PassList.getPosition(i)) {
      AddStandardLinkPasses(Passes);
      StandardLinkOpts = false;
    }

    if (OptLevelO1 && OptLevelO1.getPosition() < PassList.getPosition(i)) {
      AddOptimizationPasses(Passes, *FPasses, 1);
      OptLevelO1 = false;
//.........这里部分代码省略.........

//.........这里部分代码省略.........
    FPasses.reset(new FunctionPassManager(M.get()));
    if (DL)
      FPasses->add(new DataLayoutPass());
    if (TM)
      TM->addAnalysisPasses(*FPasses);

  }

  if (PrintBreakpoints) {
    // Default to standard output.
    if (!Out) {
      if (OutputFilename.empty())
        OutputFilename = "-";

      std::error_code EC;
      Out = llvm::make_unique<tool_output_file>(OutputFilename, EC,
                                                sys::fs::F_None);
      if (EC) {
        errs() << EC.message() << '\n';
        return 1;
      }
    }
    Passes.add(createBreakpointPrinter(Out->os()));
    NoOutput = true;
  }

  // If the -strip-debug command line option was specified, add it.
  if (StripDebug)
    addPass(Passes, createStripSymbolsPass(true));

  // Create a new optimization pass for each one specified on the command line
  for (unsigned i = 0; i < PassList.size(); ++i) {
    if (StandardLinkOpts &&
        StandardLinkOpts.getPosition() < PassList.getPosition(i)) {
      AddStandardLinkPasses(Passes);
      StandardLinkOpts = false;
    }

    if (OptLevelO1 && OptLevelO1.getPosition() < PassList.getPosition(i)) {
      AddOptimizationPasses(Passes, *FPasses, 1, 0);
      OptLevelO1 = false;
    }

    if (OptLevelO2 && OptLevelO2.getPosition() < PassList.getPosition(i)) {
      AddOptimizationPasses(Passes, *FPasses, 2, 0);
      OptLevelO2 = false;
    }

    if (OptLevelOs && OptLevelOs.getPosition() < PassList.getPosition(i)) {
      AddOptimizationPasses(Passes, *FPasses, 2, 1);
      OptLevelOs = false;
    }

    if (OptLevelOz && OptLevelOz.getPosition() < PassList.getPosition(i)) {
      AddOptimizationPasses(Passes, *FPasses, 2, 2);
      OptLevelOz = false;
    }

    if (OptLevelO3 && OptLevelO3.getPosition() < PassList.getPosition(i)) {
      AddOptimizationPasses(Passes, *FPasses, 3, 0);
      OptLevelO3 = false;
    }

    const PassInfo *PassInf = PassList[i];
    Pass *P = nullptr;
    if (PassInf->getTargetMachineCtor())