C++ global_iterator::getName方法代码示例

bool GlobalMerge::doInitialization(Module &M) {
  DenseMap<unsigned, SmallVector<GlobalVariable*, 16> > Globals, ConstGlobals,
                                                        BSSGlobals;
  const DataLayout *TD = TLI->getDataLayout();
  unsigned MaxOffset = TLI->getMaximalGlobalOffset();
  bool Changed = false;

  // Grab all non-const globals.
  for (Module::global_iterator I = M.global_begin(),
         E = M.global_end(); I != E; ++I) {
    // Merge is safe for "normal" internal globals only
    if (!I->hasLocalLinkage() || I->isThreadLocal() || I->hasSection())
      continue;

    PointerType *PT = dyn_cast<PointerType>(I->getType());
    assert(PT && "Global variable is not a pointer!");

    unsigned AddressSpace = PT->getAddressSpace();

    // Ignore fancy-aligned globals for now.
    unsigned Alignment = TD->getPreferredAlignment(I);
    Type *Ty = I->getType()->getElementType();
    if (Alignment > TD->getABITypeAlignment(Ty))
      continue;

    // Ignore all 'special' globals.
    if (I->getName().startswith("llvm.") ||
        I->getName().startswith(".llvm."))
      continue;

    if (TD->getTypeAllocSize(Ty) < MaxOffset) {
      if (TargetLoweringObjectFile::getKindForGlobal(I, TLI->getTargetMachine())
          .isBSSLocal())
        BSSGlobals[AddressSpace].push_back(I);
      else if (I->isConstant())
        ConstGlobals[AddressSpace].push_back(I);
      else
        Globals[AddressSpace].push_back(I);
    }
  }

  for (DenseMap<unsigned, SmallVector<GlobalVariable*, 16> >::iterator
       I = Globals.begin(), E = Globals.end(); I != E; ++I)
    if (I->second.size() > 1)
      Changed |= doMerge(I->second, M, false, I->first);

  for (DenseMap<unsigned, SmallVector<GlobalVariable*, 16> >::iterator
       I = BSSGlobals.begin(), E = BSSGlobals.end(); I != E; ++I)
    if (I->second.size() > 1)
      Changed |= doMerge(I->second, M, false, I->first);

  // FIXME: This currently breaks the EH processing due to way how the
  // typeinfo detection works. We might want to detect the TIs and ignore
  // them in the future.
  // if (ConstGlobals.size() > 1)
  //  Changed |= doMerge(ConstGlobals, M, true);

  return Changed;
}

bool ARMGlobalMerge::doInitialization(Module &M) {
  SmallVector<GlobalVariable*, 16> Globals, ConstGlobals, BSSGlobals;
  const TargetData *TD = TLI->getTargetData();
  unsigned MaxOffset = TLI->getMaximalGlobalOffset();
  bool Changed = false;

  // Disable this pass on darwin. The debugger is not yet ready to extract
  // variable's  info from a merged global.
  if (TLI->getTargetMachine().getSubtarget<ARMSubtarget>().isTargetDarwin())
    return false;

  // Grab all non-const globals.
  for (Module::global_iterator I = M.global_begin(),
         E = M.global_end(); I != E; ++I) {
    // Merge is safe for "normal" internal globals only
    if (!I->hasLocalLinkage() || I->isThreadLocal() || I->hasSection())
      continue;

    // Ignore fancy-aligned globals for now.
    if (I->getAlignment() != 0)
      continue;

    // Ignore all 'special' globals.
    if (I->getName().startswith("llvm.") ||
        I->getName().startswith(".llvm."))
      continue;

    if (TD->getTypeAllocSize(I->getType()->getElementType()) < MaxOffset) {
      const TargetLoweringObjectFile &TLOF = TLI->getObjFileLowering();
      if (TLOF.getKindForGlobal(I, TLI->getTargetMachine()).isBSSLocal())
        BSSGlobals.push_back(I);
      else if (I->isConstant())
        ConstGlobals.push_back(I);
      else
        Globals.push_back(I);
    }
  }

  if (Globals.size() > 1)
    Changed |= doMerge(Globals, M, false);
  if (BSSGlobals.size() > 1)
    Changed |= doMerge(BSSGlobals, M, false);

  // FIXME: This currently breaks the EH processing due to way how the 
  // typeinfo detection works. We might want to detect the TIs and ignore 
  // them in the future.
  // if (ConstGlobals.size() > 1)
  //  Changed |= doMerge(ConstGlobals, M, true);

  return Changed;
}

/// SplitFunctionsOutOfModule - Given a module and a list of functions in the
/// module, split the functions OUT of the specified module, and place them in
/// the new module.
Module *
llvm::SplitFunctionsOutOfModule(Module *M,
                                const std::vector<Function*> &F,
                                DenseMap<const Value*, Value*> &ValueMap) {
  // Make sure functions & globals are all external so that linkage
  // between the two modules will work.
  for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
    I->setLinkage(GlobalValue::ExternalLinkage);
  for (Module::global_iterator I = M->global_begin(), E = M->global_end();
       I != E; ++I) {
    if (I->hasName() && I->getName()[0] == '\01')
      I->setName(I->getName().substr(1));
    I->setLinkage(GlobalValue::ExternalLinkage);
  }

  DenseMap<const Value*, Value*> NewValueMap;
  Module *New = CloneModule(M, NewValueMap);

  // Make sure global initializers exist only in the safe module (CBE->.so)
  for (Module::global_iterator I = New->global_begin(), E = New->global_end();
       I != E; ++I)
    I->setInitializer(0);  // Delete the initializer to make it external

  // Remove the Test functions from the Safe module
  std::set<Function *> TestFunctions;
  for (unsigned i = 0, e = F.size(); i != e; ++i) {
    Function *TNOF = cast<Function>(ValueMap[F[i]]);
    DEBUG(errs() << "Removing function ");
    DEBUG(WriteAsOperand(errs(), TNOF, false));
    DEBUG(errs() << "\n");
    TestFunctions.insert(cast<Function>(NewValueMap[TNOF]));
    DeleteFunctionBody(TNOF);       // Function is now external in this module!
  }

  
  // Remove the Safe functions from the Test module
  for (Module::iterator I = New->begin(), E = New->end(); I != E; ++I)
    if (!TestFunctions.count(I))
      DeleteFunctionBody(I);
  

  // Make sure that there is a global ctor/dtor array in both halves of the
  // module if they both have static ctor/dtor functions.
  SplitStaticCtorDtor("llvm.global_ctors", M, New, NewValueMap);
  SplitStaticCtorDtor("llvm.global_dtors", M, New, NewValueMap);
  
  return New;
}

/// GetAllUndefinedSymbols - calculates the set of undefined symbols that still
/// exist in an LLVM module. This is a bit tricky because there may be two
/// symbols with the same name but different LLVM types that will be resolved to
/// each other but aren't currently (thus we need to treat it as resolved).
///
/// Inputs:
///  M - The module in which to find undefined symbols.
///
/// Outputs:
///  UndefinedSymbols - A set of C++ strings containing the name of all
///                     undefined symbols.
///
static void
GetAllUndefinedSymbols(Module *M, std::set<std::string> &UndefinedSymbols) {
  std::set<std::string> DefinedSymbols;
  UndefinedSymbols.clear();

  // If the program doesn't define a main, try pulling one in from a .a file.
  // This is needed for programs where the main function is defined in an
  // archive, such f2c'd programs.
  Function *Main = M->getFunction("main");
  if (Main == 0 || Main->isDeclaration())
    UndefinedSymbols.insert("main");

  for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
    if (I->hasName()) {
      if (I->isDeclaration())
        UndefinedSymbols.insert(I->getName());
      else if (!I->hasLocalLinkage()) {
        assert(!I->hasDLLImportLinkage()
               && "Found dllimported non-external symbol!");
        DefinedSymbols.insert(I->getName());
      }      
    }

  for (Module::global_iterator I = M->global_begin(), E = M->global_end();
       I != E; ++I)
    if (I->hasName()) {
      if (I->isDeclaration())
        UndefinedSymbols.insert(I->getName());
      else if (!I->hasLocalLinkage()) {
        assert(!I->hasDLLImportLinkage()
               && "Found dllimported non-external symbol!");
        DefinedSymbols.insert(I->getName());
      }      
    }

  for (Module::alias_iterator I = M->alias_begin(), E = M->alias_end();
       I != E; ++I)
    if (I->hasName())
      DefinedSymbols.insert(I->getName());

  // Prune out any defined symbols from the undefined symbols set...
  for (std::set<std::string>::iterator I = UndefinedSymbols.begin();
       I != UndefinedSymbols.end(); )
    if (DefinedSymbols.count(*I))
      UndefinedSymbols.erase(I++);  // This symbol really is defined!
    else
      ++I; // Keep this symbol in the undefined symbols list
}

void MemoryInstrumenter::instrumentGlobals(Module &M) {
  TargetData &TD = getAnalysis<TargetData>();
  IDAssigner &IDA = getAnalysis<IDAssigner>();

  // Function HookGlobalsAlloc contains only one basic block.
  // The BB iterates through all global variables, and calls HookMemAlloc
  // for each of them.
  BasicBlock *BB = BasicBlock::Create(M.getContext(), "entry",
                                      GlobalsAllocHook);
  Instruction *Ret = ReturnInst::Create(M.getContext(), BB);

  for (Module::global_iterator GI = M.global_begin(), E = M.global_end();
       GI != E; ++GI) {
    // We are going to delete llvm.global_ctors.
    // Therefore, don't instrument it.
    if (GI->getName() == "llvm.global_ctors")
      continue;
    // Prevent global variables from sharing the same address, because it
    // breaks the assumption that global variables do not alias.
    // The same goes to functions.
    if (GI->hasUnnamedAddr()) {
      GI->setUnnamedAddr(false);
    }
    uint64_t TypeSize = TD.getTypeStoreSize(GI->getType()->getElementType());
    instrumentMemoryAllocation(GI,
                               ConstantInt::get(LongType, TypeSize),
                               NULL,
                               Ret);
    instrumentPointer(GI, NULL, Ret);
  }

  for (Module::iterator F = M.begin(); F != M.end(); ++F) {
    // These hooks added by us don't have a value ID.
    if (MemAllocHook == F || MainArgsAllocHook == F || TopLevelHook == F ||
        AddrTakenHook == F || CallHook == F || ReturnHook == F ||
        GlobalsAllocHook == F || MemHooksIniter == F || AfterForkHook == F ||
        BeforeForkHook == F) {
      continue;
    }
    // InvalidID: maybe this is inserted by alias checker in hybrid mode.
    if (IDA.getValueID(F) == IDAssigner::InvalidID)
      continue;
    // Ignore intrinsic functions because we cannot take the address of
    // an intrinsic. Also, no function pointers will point to instrinsic
    // functions.
    if (F->isIntrinsic())
      continue;
    // Prevent functions from sharing the same address.
    if (F->hasUnnamedAddr()) {
      F->setUnnamedAddr(false);
    }
    uint64_t TypeSize = TD.getTypeStoreSize(F->getType());
    assert(TypeSize == TD.getPointerSize());
    instrumentMemoryAllocation(F,
                               ConstantInt::get(LongType, TypeSize),
                               NULL,
                               Ret);
    instrumentPointer(F, NULL, Ret);
  }
}

/// StripSymbolNames - Strip symbol names.
static bool StripSymbolNames(Module &M, bool PreserveDbgInfo) {

  SmallPtrSet<const GlobalValue*, 8> llvmUsedValues;
  findUsedValues(M.getGlobalVariable("llvm.used"), llvmUsedValues);
  findUsedValues(M.getGlobalVariable("llvm.compiler.used"), llvmUsedValues);

  for (Module::global_iterator I = M.global_begin(), E = M.global_end();
       I != E; ++I) {
    if (I->hasLocalLinkage() && llvmUsedValues.count(I) == 0)
      if (!PreserveDbgInfo || !I->getName().startswith("llvm.dbg"))
        I->setName("");     // Internal symbols can't participate in linkage
  }
  
  for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I) {
    if (I->hasLocalLinkage() && llvmUsedValues.count(I) == 0)
      if (!PreserveDbgInfo || !I->getName().startswith("llvm.dbg"))
        I->setName("");     // Internal symbols can't participate in linkage
    StripSymtab(I->getValueSymbolTable(), PreserveDbgInfo);
  }
  
  // Remove all names from types.
  StripTypeSymtab(M.getTypeSymbolTable(), PreserveDbgInfo);

  return true;
}

void LTOCodeGenerator::applyScopeRestrictions()
{
    if ( !_scopeRestrictionsDone ) {
        Module* mergedModule = _linker.getModule();

        // Start off with a verification pass.
        PassManager passes;
        passes.add(createVerifierPass());

        // mark which symbols can not be internalized 
        if ( !_mustPreserveSymbols.empty() ) {
            Mangler mangler(*mergedModule, 
                                _target->getTargetAsmInfo()->getGlobalPrefix());
            std::vector<const char*> mustPreserveList;
            for (Module::iterator f = mergedModule->begin(), 
                                        e = mergedModule->end(); f != e; ++f) {
                if ( !f->isDeclaration() 
                  && _mustPreserveSymbols.count(mangler.getValueName(f)) )
                    mustPreserveList.push_back(::strdup(f->getName().c_str()));
            }
            for (Module::global_iterator v = mergedModule->global_begin(), 
                                 e = mergedModule->global_end(); v !=  e; ++v) {
                if ( !v->isDeclaration()
                  && _mustPreserveSymbols.count(mangler.getValueName(v)) )
                    mustPreserveList.push_back(::strdup(v->getName().c_str()));
            }
            passes.add(createInternalizePass(mustPreserveList));
        }
        // apply scope restrictions
        passes.run(*mergedModule);
        
        _scopeRestrictionsDone = true;
    }
}

void
AndroidBitcodeLinker::GetAllSymbols(Module *M,
  std::set<std::string> &UndefinedSymbols,
  std::set<std::string> &DefinedSymbols) {

  UndefinedSymbols.clear();
  DefinedSymbols.clear();

  Function *Main = M->getFunction("main");
  if (Main == 0 || Main->isDeclaration())
    UndefinedSymbols.insert("main");

  for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
    if (I->hasName()) {
      if (I->isDeclaration())
        UndefinedSymbols.insert(I->getName());
      else if (!I->hasLocalLinkage()) {
        assert(!I->hasDLLImportStorageClass()
               && "Found dllimported non-external symbol!");
        DefinedSymbols.insert(I->getName());
      }
    }

  for (Module::global_iterator I = M->global_begin(), E = M->global_end();
       I != E; ++I)
    if (I->hasName()) {
      if (I->isDeclaration())
        UndefinedSymbols.insert(I->getName());
      else if (!I->hasLocalLinkage()) {
        assert(!I->hasDLLImportStorageClass()
               && "Found dllimported non-external symbol!");
        DefinedSymbols.insert(I->getName());
      }
    }

  for (Module::alias_iterator I = M->alias_begin(), E = M->alias_end();
       I != E; ++I)
    if (I->hasName())
      DefinedSymbols.insert(I->getName());

  for (std::set<std::string>::iterator I = UndefinedSymbols.begin();
       I != UndefinedSymbols.end(); )
    if (DefinedSymbols.count(*I))
      UndefinedSymbols.erase(I++);
    else
      ++I;
}

static void getSymbols(Module*M, std::vector<std::string>& symbols) {
    // Loop over global variables
    for (Module::global_iterator GI = M->global_begin(), GE=M->global_end(); GI != GE; ++GI)
        if (!GI->isDeclaration() && !GI->hasLocalLinkage())
            if (!GI->getName().empty())
                symbols.push_back(GI->getName());

    // Loop over functions
    for (Module::iterator FI = M->begin(), FE = M->end(); FI != FE; ++FI)
        if (!FI->isDeclaration() && !FI->hasLocalLinkage())
            if (!FI->getName().empty())
                symbols.push_back(FI->getName());

    // Loop over aliases
    for (Module::alias_iterator AI = M->alias_begin(), AE = M->alias_end();
            AI != AE; ++AI) {
        if (AI->hasName())
            symbols.push_back(AI->getName());
    }
}

bool ARMGlobalMerge::doInitialization(Module &M) {
  SmallVector<GlobalVariable*, 16> Globals, ConstGlobals;
  const TargetData *TD = TLI->getTargetData();
  unsigned MaxOffset = TLI->getMaximalGlobalOffset();
  bool Changed = false;

  // Grab all non-const globals.
  for (Module::global_iterator I = M.global_begin(),
         E = M.global_end(); I != E; ++I) {
    // Merge is safe for "normal" internal globals only
    if (!I->hasLocalLinkage() || I->isThreadLocal() || I->hasSection())
      continue;

    // Ignore fancy-aligned globals for now.
    if (I->getAlignment() != 0)
      continue;

    // Ignore all 'special' globals.
    if (I->getName().startswith("llvm.") ||
        I->getName().startswith(".llvm."))
      continue;

    if (TD->getTypeAllocSize(I->getType()) < MaxOffset) {
      if (I->isConstant())
        ConstGlobals.push_back(I);
      else
        Globals.push_back(I);
    }
  }

  if (Globals.size() > 1)
    Changed |= doMerge(Globals, M, false);
  // FIXME: This currently breaks the EH processing due to way how the 
  // typeinfo detection works. We might want to detect the TIs and ignore 
  // them in the future.
  
  // if (ConstGlobals.size() > 1)
  //  Changed |= doMerge(ConstGlobals, M, true);

  return Changed;
}

/// DisambiguateGlobalSymbols - Mangle symbols to guarantee uniqueness by
/// modifying predominantly internal symbols rather than external ones.
///
static void DisambiguateGlobalSymbols(Module *M) {
  // Try not to cause collisions by minimizing chances of renaming an
  // already-external symbol, so take in external globals and functions as-is.
  // The code should work correctly without disambiguation (assuming the same
  // mangler is used by the two code generators), but having symbols with the
  // same name causes warnings to be emitted by the code generator.
  Mangler Mang(*M);
  // Agree with the CBE on symbol naming
  Mang.markCharUnacceptable('.');
  for (Module::global_iterator I = M->global_begin(), E = M->global_end();
       I != E; ++I) {
    // Don't mangle asm names.
    if (!I->hasName() || I->getName()[0] != 1)
      I->setName(Mang.getMangledName(I));
  }
  for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I) {
    // Don't mangle asm names or intrinsics.
    if ((!I->hasName() || I->getName()[0] != 1) &&
        I->getIntrinsicID() == 0)
      I->setName(Mang.getMangledName(I));
  }
}

bool InternalizePass::runOnModule(Module &M) {
  CallGraph *CG = getAnalysisIfAvailable<CallGraph>();
  CallGraphNode *ExternalNode = CG ? CG->getExternalCallingNode() : 0;
  bool Changed = false;

  // Never internalize functions which code-gen might insert.
  // FIXME: We should probably add this (and the __stack_chk_guard) via some
  // type of call-back in CodeGen.
  ExternalNames.insert("__stack_chk_fail");

  // Mark all functions not in the api as internal.
  // FIXME: maybe use private linkage?
  for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
    if (!I->isDeclaration() &&         // Function must be defined here
        // Available externally is really just a "declaration with a body".
        !I->hasAvailableExternallyLinkage() &&
        !I->hasLocalLinkage() &&  // Can't already have internal linkage
        !ExternalNames.count(I->getName())) {// Not marked to keep external?
      I->setLinkage(GlobalValue::InternalLinkage);
      // Remove a callgraph edge from the external node to this function.
      if (ExternalNode) ExternalNode->removeOneAbstractEdgeTo((*CG)[I]);
      Changed = true;
      ++NumFunctions;
      DEBUG(dbgs() << "Internalizing func " << I->getName() << "\n");
    }

  // Never internalize the llvm.used symbol.  It is used to implement
  // attribute((used)).
  // FIXME: Shouldn't this just filter on llvm.metadata section??
  ExternalNames.insert("llvm.used");
  ExternalNames.insert("llvm.compiler.used");

  // Never internalize anchors used by the machine module info, else the info
  // won't find them.  (see MachineModuleInfo.)
  ExternalNames.insert("llvm.global_ctors");
  ExternalNames.insert("llvm.global_dtors");
  ExternalNames.insert("llvm.global.annotations");

  // Never internalize symbols code-gen inserts.
  ExternalNames.insert("__stack_chk_guard");

  // Mark all global variables with initializers that are not in the api as
  // internal as well.
  // FIXME: maybe use private linkage?
  for (Module::global_iterator I = M.global_begin(), E = M.global_end();
       I != E; ++I)
    if (!I->isDeclaration() && !I->hasLocalLinkage() &&
        // Available externally is really just a "declaration with a body".
        !I->hasAvailableExternallyLinkage() &&
        !ExternalNames.count(I->getName())) {
      I->setLinkage(GlobalValue::InternalLinkage);
      Changed = true;
      ++NumGlobals;
      DEBUG(dbgs() << "Internalized gvar " << I->getName() << "\n");
    }

  // Mark all aliases that are not in the api as internal as well.
  for (Module::alias_iterator I = M.alias_begin(), E = M.alias_end();
       I != E; ++I)
    if (!I->isDeclaration() && !I->hasInternalLinkage() &&
        // Available externally is really just a "declaration with a body".
        !I->hasAvailableExternallyLinkage() &&
        !ExternalNames.count(I->getName())) {
      I->setLinkage(GlobalValue::InternalLinkage);
      Changed = true;
      ++NumAliases;
      DEBUG(dbgs() << "Internalized alias " << I->getName() << "\n");
    }

  return Changed;
}

/// SplitFunctionsOutOfModule - Given a module and a list of functions in the
/// module, split the functions OUT of the specified module, and place them in
/// the new module.
Module *
llvm::SplitFunctionsOutOfModule(Module *M,
                                const std::vector<Function*> &F,
                                ValueToValueMapTy &VMap) {
  // Make sure functions & globals are all external so that linkage
  // between the two modules will work.
  for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
    I->setLinkage(GlobalValue::ExternalLinkage);
  for (Module::global_iterator I = M->global_begin(), E = M->global_end();
       I != E; ++I) {
    if (I->hasName() && I->getName()[0] == '\01')
      I->setName(I->getName().substr(1));
    I->setLinkage(GlobalValue::ExternalLinkage);
  }

  ValueToValueMapTy NewVMap;
  Module *New = CloneModule(M, NewVMap);

  // Remove the Test functions from the Safe module
  std::set<Function *> TestFunctions;
  for (unsigned i = 0, e = F.size(); i != e; ++i) {
    Function *TNOF = cast<Function>(VMap[F[i]]);
    DEBUG(errs() << "Removing function ");
    DEBUG(WriteAsOperand(errs(), TNOF, false));
    DEBUG(errs() << "\n");
    TestFunctions.insert(cast<Function>(NewVMap[TNOF]));
    DeleteFunctionBody(TNOF);       // Function is now external in this module!
  }

  
  // Remove the Safe functions from the Test module
  for (Module::iterator I = New->begin(), E = New->end(); I != E; ++I)
    if (!TestFunctions.count(I))
      DeleteFunctionBody(I);
  

  // Try to split the global initializers evenly
  for (Module::global_iterator I = M->global_begin(), E = M->global_end();
       I != E; ++I) {
    GlobalVariable *GV = cast<GlobalVariable>(NewVMap[I]);
    if (Function *TestFn = globalInitUsesExternalBA(I)) {
      if (Function *SafeFn = globalInitUsesExternalBA(GV)) {
        errs() << "*** Error: when reducing functions, encountered "
                  "the global '";
        WriteAsOperand(errs(), GV, false);
        errs() << "' with an initializer that references blockaddresses "
                  "from safe function '" << SafeFn->getName()
               << "' and from test function '" << TestFn->getName() << "'.\n";
        exit(1);
      }
      I->setInitializer(0);  // Delete the initializer to make it external
    } else {
      // If we keep it in the safe module, then delete it in the test module
      GV->setInitializer(0);
    }
  }

  // Make sure that there is a global ctor/dtor array in both halves of the
  // module if they both have static ctor/dtor functions.
  SplitStaticCtorDtor("llvm.global_ctors", M, New, NewVMap);
  SplitStaticCtorDtor("llvm.global_dtors", M, New, NewVMap);
  
  return New;
}

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

  LLVMContext &Context = getGlobalContext();
  llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
  cl::ParseCommandLineOptions(argc, argv, "llvm extractor\n");

  // Use lazy loading, since we only care about selected global values.
  SMDiagnostic Err;
  std::auto_ptr<Module> M;
  M.reset(getLazyIRFileModule(InputFilename, Err, Context));

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

  // Use SetVector to avoid duplicates.
  SetVector<GlobalValue *> GVs;

  // Figure out which globals we should extract.
  for (size_t i = 0, e = ExtractGlobals.size(); i != e; ++i) {
    GlobalValue *GV = M.get()->getNamedGlobal(ExtractGlobals[i]);
    if (!GV) {
      errs() << argv[0] << ": program doesn't contain global named '"
             << ExtractGlobals[i] << "'!\n";
      return 1;
    }
    GVs.insert(GV);
  }

  // Extract globals via regular expression matching.
  for (size_t i = 0, e = ExtractRegExpGlobals.size(); i != e; ++i) {
    std::string Error;
    Regex RegEx(ExtractRegExpGlobals[i]);
    if (!RegEx.isValid(Error)) {
      errs() << argv[0] << ": '" << ExtractRegExpGlobals[i] << "' "
        "invalid regex: " << Error;
    }
    bool match = false;
    for (Module::global_iterator GV = M.get()->global_begin(), 
           E = M.get()->global_end(); GV != E; GV++) {
      if (RegEx.match(GV->getName())) {
        GVs.insert(&*GV);
        match = true;
      }
    }
    if (!match) {
      errs() << argv[0] << ": program doesn't contain global named '"
             << ExtractRegExpGlobals[i] << "'!\n";
      return 1;
    }
  }

  // Figure out which functions we should extract.
  for (size_t i = 0, e = ExtractFuncs.size(); i != e; ++i) {
    GlobalValue *GV = M.get()->getFunction(ExtractFuncs[i]);
    if (!GV) {
      errs() << argv[0] << ": program doesn't contain function named '"
             << ExtractFuncs[i] << "'!\n";
      return 1;
    }
    GVs.insert(GV);
  }
  // Extract functions via regular expression matching.
  for (size_t i = 0, e = ExtractRegExpFuncs.size(); i != e; ++i) {
    std::string Error;
    StringRef RegExStr = ExtractRegExpFuncs[i];
    Regex RegEx(RegExStr);
    if (!RegEx.isValid(Error)) {
      errs() << argv[0] << ": '" << ExtractRegExpFuncs[i] << "' "
        "invalid regex: " << Error;
    }
    bool match = false;
    for (Module::iterator F = M.get()->begin(), E = M.get()->end(); F != E; 
         F++) {
      if (RegEx.match(F->getName())) {
        GVs.insert(&*F);
        match = true;
      }
    }
    if (!match) {
      errs() << argv[0] << ": program doesn't contain global named '"
             << ExtractRegExpFuncs[i] << "'!\n";
      return 1;
    }
  }

  // Materialize requisite global values.
  if (!DeleteFn)
    for (size_t i = 0, e = GVs.size(); i != e; ++i) {
      GlobalValue *GV = GVs[i];
      if (GV->isMaterializable()) {
        std::string ErrInfo;
        if (GV->Materialize(&ErrInfo)) {
          errs() << argv[0] << ": error reading input: " << ErrInfo << "\n";
          return 1;
        }
//.........这里部分代码省略.........

static PointerType *buildTlsTemplate(Module &M, std::vector<VarInfo> *TlsVars) {
  std::vector<Type*> FieldBssTypes;
  std::vector<Type*> FieldInitTypes;
  std::vector<Constant*> FieldInitValues;
  PassState State(&M);

  for (Module::global_iterator GV = M.global_begin();
       GV != M.global_end();
       ++GV) {
    if (GV->isThreadLocal()) {
      if (!GV->hasInitializer()) {
        // Since this is a whole-program transformation, "extern" TLS
        // variables are not allowed at this point.
        report_fatal_error(std::string("TLS variable without an initializer: ")
                           + GV->getName());
      }
      if (!GV->getInitializer()->isNullValue()) {
        addVarToTlsTemplate(&State, &FieldInitTypes,
                            &FieldInitValues, GV);
        VarInfo Info;
        Info.TlsVar = GV;
        Info.IsBss = false;
        Info.TemplateIndex = FieldInitTypes.size() - 1;
        TlsVars->push_back(Info);
      }
    }
  }
  // Handle zero-initialized TLS variables in a second pass, because
  // these should follow non-zero-initialized TLS variables.
  for (Module::global_iterator GV = M.global_begin();
       GV != M.global_end();
       ++GV) {
    if (GV->isThreadLocal() && GV->getInitializer()->isNullValue()) {
      addVarToTlsTemplate(&State, &FieldBssTypes, NULL, GV);
      VarInfo Info;
      Info.TlsVar = GV;
      Info.IsBss = true;
      Info.TemplateIndex = FieldBssTypes.size() - 1;
      TlsVars->push_back(Info);
    }
  }
  // Add final alignment padding so that
  //   (struct tls_struct *) __nacl_read_tp() - 1
  // gives the correct, aligned start of the TLS variables given the
  // x86-style layout we are using.  This requires some more bytes to
  // be memset() to zero at runtime.  This wastage doesn't seem
  // important gives that we're not trying to optimize packing by
  // reordering to put similarly-aligned variables together.
  padToAlignment(&State, &FieldBssTypes, NULL, State.Alignment);

  // We create the TLS template structs as "packed" because we insert
  // alignment padding ourselves, and LLVM's implicit insertion of
  // padding would interfere with ours.  tls_bss_template can start at
  // a non-aligned address immediately following the last field in
  // tls_init_template.
  StructType *InitTemplateType =
      StructType::create(M.getContext(), "tls_init_template");
  InitTemplateType->setBody(FieldInitTypes, /*isPacked=*/true);
  StructType *BssTemplateType =
      StructType::create(M.getContext(), "tls_bss_template");
  BssTemplateType->setBody(FieldBssTypes, /*isPacked=*/true);

  StructType *TemplateType = StructType::create(M.getContext(), "tls_struct");
  SmallVector<Type*, 2> TemplateTopFields;
  TemplateTopFields.push_back(InitTemplateType);
  TemplateTopFields.push_back(BssTemplateType);
  TemplateType->setBody(TemplateTopFields, /*isPacked=*/true);
  PointerType *TemplatePtrType = PointerType::get(TemplateType, 0);

  // We define the following symbols, which are the same as those
  // defined by NaCl's original customized binutils linker scripts:
  //   __tls_template_start
  //   __tls_template_tdata_end
  //   __tls_template_end
  // We also define __tls_template_alignment, which was not defined by
  // the original linker scripts.

  const char *StartSymbol = "__tls_template_start";
  Constant *TemplateData = ConstantStruct::get(InitTemplateType,
                                               FieldInitValues);
  GlobalVariable *TemplateDataVar =
      new GlobalVariable(M, InitTemplateType, /*isConstant=*/true,
                         GlobalValue::InternalLinkage, TemplateData);
  setGlobalVariableValue(M, StartSymbol, TemplateDataVar);
  TemplateDataVar->setName(StartSymbol);

  Constant *TdataEnd = ConstantExpr::getGetElementPtr(
      TemplateDataVar,
      ConstantInt::get(M.getContext(), APInt(32, 1)));
  setGlobalVariableValue(M, "__tls_template_tdata_end", TdataEnd);

  Constant *TotalEnd = ConstantExpr::getGetElementPtr(
      ConstantExpr::getBitCast(TemplateDataVar, TemplatePtrType),
      ConstantInt::get(M.getContext(), APInt(32, 1)));
  setGlobalVariableValue(M, "__tls_template_end", TotalEnd);

  const char *AlignmentSymbol = "__tls_template_alignment";
  Type *i32 = Type::getInt32Ty(M.getContext());
  GlobalVariable *AlignmentVar = new GlobalVariable(
      M, i32, /*isConstant=*/true,
//.........这里部分代码省略.........