예제 #1
0
파일: CloneModule.cpp 프로젝트: Drup/llvm
Module *llvm::CloneModule(const Module *M, ValueToValueMapTy &VMap) {
  // First off, we need to create the new module.
  Module *New = new Module(M->getModuleIdentifier(), M->getContext());
  New->setDataLayout(M->getDataLayout());
  New->setTargetTriple(M->getTargetTriple());
  New->setModuleInlineAsm(M->getModuleInlineAsm());
   
  // Loop over all of the global variables, making corresponding globals in the
  // new module.  Here we add them to the VMap and to the new Module.  We
  // don't worry about attributes or initializers, they will come later.
  //
  for (Module::const_global_iterator I = M->global_begin(), E = M->global_end();
       I != E; ++I) {
    GlobalVariable *GV = new GlobalVariable(*New, 
                                            I->getType()->getElementType(),
                                            I->isConstant(), I->getLinkage(),
                                            (Constant*) nullptr, I->getName(),
                                            (GlobalVariable*) nullptr,
                                            I->getThreadLocalMode(),
                                            I->getType()->getAddressSpace());
    GV->copyAttributesFrom(I);
    VMap[I] = GV;
  }

  // Loop over the functions in the module, making external functions as before
  for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I) {
    Function *NF =
      Function::Create(cast<FunctionType>(I->getType()->getElementType()),
                       I->getLinkage(), I->getName(), New);
    NF->copyAttributesFrom(I);
    VMap[I] = NF;
  }

  // Loop over the aliases in the module
  for (Module::const_alias_iterator I = M->alias_begin(), E = M->alias_end();
       I != E; ++I) {
    auto *PTy = cast<PointerType>(I->getType());
    auto *GA =
        GlobalAlias::create(PTy->getElementType(), PTy->getAddressSpace(),
                            I->getLinkage(), I->getName(), New);
    GA->copyAttributesFrom(I);
    VMap[I] = GA;
  }
  
  // Now that all of the things that global variable initializer can refer to
  // have been created, loop through and copy the global variable referrers
  // over...  We also set the attributes on the global now.
  //
  for (Module::const_global_iterator I = M->global_begin(), E = M->global_end();
       I != E; ++I) {
    GlobalVariable *GV = cast<GlobalVariable>(VMap[I]);
    if (I->hasInitializer())
      GV->setInitializer(MapValue(I->getInitializer(), VMap));
  }

  // Similarly, copy over function bodies now...
  //
  for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I) {
    Function *F = cast<Function>(VMap[I]);
    if (!I->isDeclaration()) {
      Function::arg_iterator DestI = F->arg_begin();
      for (Function::const_arg_iterator J = I->arg_begin(); J != I->arg_end();
           ++J) {
        DestI->setName(J->getName());
        VMap[J] = DestI++;
      }

      SmallVector<ReturnInst*, 8> Returns;  // Ignore returns cloned.
      CloneFunctionInto(F, I, VMap, /*ModuleLevelChanges=*/true, Returns);
    }
  }

  // And aliases
  for (Module::const_alias_iterator I = M->alias_begin(), E = M->alias_end();
       I != E; ++I) {
    GlobalAlias *GA = cast<GlobalAlias>(VMap[I]);
    if (const Constant *C = I->getAliasee())
      GA->setAliasee(cast<GlobalObject>(MapValue(C, VMap)));
  }

  // And named metadata....
  for (Module::const_named_metadata_iterator I = M->named_metadata_begin(),
         E = M->named_metadata_end(); I != E; ++I) {
    const NamedMDNode &NMD = *I;
    NamedMDNode *NewNMD = New->getOrInsertNamedMetadata(NMD.getName());
    for (unsigned i = 0, e = NMD.getNumOperands(); i != e; ++i)
      NewNMD->addOperand(MapValue(NMD.getOperand(i), VMap));
  }

  return New;
}
예제 #2
0
std::unique_ptr<Module> llvm::CloneModule(
    const Module *M, ValueToValueMapTy &VMap,
    std::function<bool(const GlobalValue *)> ShouldCloneDefinition) {
  // First off, we need to create the new module.
  std::unique_ptr<Module> New =
      llvm::make_unique<Module>(M->getModuleIdentifier(), M->getContext());
  New->setDataLayout(M->getDataLayout());
  New->setTargetTriple(M->getTargetTriple());
  New->setModuleInlineAsm(M->getModuleInlineAsm());
   
  // Loop over all of the global variables, making corresponding globals in the
  // new module.  Here we add them to the VMap and to the new Module.  We
  // don't worry about attributes or initializers, they will come later.
  //
  for (Module::const_global_iterator I = M->global_begin(), E = M->global_end();
       I != E; ++I) {
    GlobalVariable *GV = new GlobalVariable(*New, 
                                            I->getValueType(),
                                            I->isConstant(), I->getLinkage(),
                                            (Constant*) nullptr, I->getName(),
                                            (GlobalVariable*) nullptr,
                                            I->getThreadLocalMode(),
                                            I->getType()->getAddressSpace());
    GV->copyAttributesFrom(&*I);
    VMap[&*I] = GV;
  }

  // Loop over the functions in the module, making external functions as before
  for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I) {
    Function *NF =
        Function::Create(cast<FunctionType>(I->getValueType()),
                         I->getLinkage(), I->getName(), New.get());
    NF->copyAttributesFrom(&*I);
    VMap[&*I] = NF;
  }

  // Loop over the aliases in the module
  for (Module::const_alias_iterator I = M->alias_begin(), E = M->alias_end();
       I != E; ++I) {
    if (!ShouldCloneDefinition(&*I)) {
      // An alias cannot act as an external reference, so we need to create
      // either a function or a global variable depending on the value type.
      // FIXME: Once pointee types are gone we can probably pick one or the
      // other.
      GlobalValue *GV;
      if (I->getValueType()->isFunctionTy())
        GV = Function::Create(cast<FunctionType>(I->getValueType()),
                              GlobalValue::ExternalLinkage, I->getName(),
                              New.get());
      else
        GV = new GlobalVariable(
            *New, I->getValueType(), false, GlobalValue::ExternalLinkage,
            (Constant *)nullptr, I->getName(), (GlobalVariable *)nullptr,
            I->getThreadLocalMode(), I->getType()->getAddressSpace());
      VMap[&*I] = GV;
      // We do not copy attributes (mainly because copying between different
      // kinds of globals is forbidden), but this is generally not required for
      // correctness.
      continue;
    }
    auto *GA = GlobalAlias::create(I->getValueType(),
                                   I->getType()->getPointerAddressSpace(),
                                   I->getLinkage(), I->getName(), New.get());
    GA->copyAttributesFrom(&*I);
    VMap[&*I] = GA;
  }
  
  // Now that all of the things that global variable initializer can refer to
  // have been created, loop through and copy the global variable referrers
  // over...  We also set the attributes on the global now.
  //
  for (Module::const_global_iterator I = M->global_begin(), E = M->global_end();
       I != E; ++I) {
    GlobalVariable *GV = cast<GlobalVariable>(VMap[&*I]);
    if (!ShouldCloneDefinition(&*I)) {
      // Skip after setting the correct linkage for an external reference.
      GV->setLinkage(GlobalValue::ExternalLinkage);
      continue;
    }
    if (I->hasInitializer())
      GV->setInitializer(MapValue(I->getInitializer(), VMap));
  }

  // Similarly, copy over function bodies now...
  //
  for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I) {
    Function *F = cast<Function>(VMap[&*I]);
    if (!ShouldCloneDefinition(&*I)) {
      // Skip after setting the correct linkage for an external reference.
      F->setLinkage(GlobalValue::ExternalLinkage);
      // Personality function is not valid on a declaration.
      F->setPersonalityFn(nullptr);
      continue;
    }
    if (!I->isDeclaration()) {
      Function::arg_iterator DestI = F->arg_begin();
      for (Function::const_arg_iterator J = I->arg_begin(); J != I->arg_end();
           ++J) {
        DestI->setName(J->getName());
        VMap[&*J] = &*DestI++;
      }

      SmallVector<ReturnInst*, 8> Returns;  // Ignore returns cloned.
      CloneFunctionInto(F, &*I, VMap, /*ModuleLevelChanges=*/true, Returns);
    }

    if (I->hasPersonalityFn())
      F->setPersonalityFn(MapValue(I->getPersonalityFn(), VMap));
  }

  // And aliases
  for (Module::const_alias_iterator I = M->alias_begin(), E = M->alias_end();
       I != E; ++I) {
    // We already dealt with undefined aliases above.
    if (!ShouldCloneDefinition(&*I))
      continue;
    GlobalAlias *GA = cast<GlobalAlias>(VMap[&*I]);
    if (const Constant *C = I->getAliasee())
      GA->setAliasee(MapValue(C, VMap));
  }

  // And named metadata....
  for (Module::const_named_metadata_iterator I = M->named_metadata_begin(),
         E = M->named_metadata_end(); I != E; ++I) {
    const NamedMDNode &NMD = *I;
    NamedMDNode *NewNMD = New->getOrInsertNamedMetadata(NMD.getName());
    for (unsigned i = 0, e = NMD.getNumOperands(); i != e; ++i)
      NewNMD->addOperand(MapMetadata(NMD.getOperand(i), VMap));
  }

  return New;
}
예제 #3
0
void externalsAndGlobalsCheck(const Module *m) {
  std::map<std::string, bool> externals;
  std::set<std::string> modelled(modelledExternals,
                                 modelledExternals+NELEMS(modelledExternals));
  std::set<std::string> dontCare(dontCareExternals,
                                 dontCareExternals+NELEMS(dontCareExternals));
  std::set<std::string> unsafe(unsafeExternals,
                               unsafeExternals+NELEMS(unsafeExternals));

  switch (Libc) {
  case KleeLibc:
    dontCare.insert(dontCareKlee, dontCareKlee+NELEMS(dontCareKlee));
    break;
  case UcLibc:
    dontCare.insert(dontCareUclibc,
                    dontCareUclibc+NELEMS(dontCareUclibc));
    break;
  case NoLibc: /* silence compiler warning */
    break;
  }

  if (WithPOSIXRuntime)
    dontCare.insert("syscall");

  for (Module::const_iterator fnIt = m->begin(), fn_ie = m->end();
       fnIt != fn_ie; ++fnIt) {
    if (fnIt->isDeclaration() && !fnIt->use_empty())
      externals.insert(std::make_pair(fnIt->getName(), false));
    for (Function::const_iterator bbIt = fnIt->begin(), bb_ie = fnIt->end();
         bbIt != bb_ie; ++bbIt) {
      for (BasicBlock::const_iterator it = bbIt->begin(), ie = bbIt->end();
           it != ie; ++it) {
        if (const CallInst *ci = dyn_cast<CallInst>(it)) {
          if (isa<InlineAsm>(ci->getCalledValue())) {
            klee_warning_once(&*fnIt,
                              "function \"%s\" has inline asm",
                              fnIt->getName().data());
          }
        }
      }
    }
  }
  for (Module::const_global_iterator
         it = m->global_begin(), ie = m->global_end();
       it != ie; ++it)
    if (it->isDeclaration() && !it->use_empty())
      externals.insert(std::make_pair(it->getName(), true));
  // and remove aliases (they define the symbol after global
  // initialization)
  for (Module::const_alias_iterator
         it = m->alias_begin(), ie = m->alias_end();
       it != ie; ++it) {
    std::map<std::string, bool>::iterator it2 =
      externals.find(it->getName());
    if (it2!=externals.end())
      externals.erase(it2);
  }

  std::map<std::string, bool> foundUnsafe;
  for (std::map<std::string, bool>::iterator
         it = externals.begin(), ie = externals.end();
       it != ie; ++it) {
    const std::string &ext = it->first;
    if (!modelled.count(ext) && (WarnAllExternals ||
                                 !dontCare.count(ext))) {
      if (unsafe.count(ext)) {
        foundUnsafe.insert(*it);
      } else {
        klee_warning("undefined reference to %s: %s",
                     it->second ? "variable" : "function",
                     ext.c_str());
      }
    }
  }

  for (std::map<std::string, bool>::iterator
         it = foundUnsafe.begin(), ie = foundUnsafe.end();
       it != ie; ++it) {
    const std::string &ext = it->first;
    klee_warning("undefined reference to %s: %s (UNSAFE)!",
                 it->second ? "variable" : "function",
                 ext.c_str());
  }
}
예제 #4
0
/// Based on GetAllUndefinedSymbols() from LLVM3.2
///
/// 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) {
  static const std::string llvmIntrinsicPrefix="llvm.";
  std::set<std::string> DefinedSymbols;
  UndefinedSymbols.clear();
  KLEE_DEBUG_WITH_TYPE("klee_linker",
                       dbgs() << "*** Computing undefined symbols for "
                              << M->getModuleIdentifier() << " ***\n");

  for (auto const &Function : *M) {
    if (Function.hasName()) {
      if (Function.isDeclaration())
        UndefinedSymbols.insert(Function.getName());
      else if (!Function.hasLocalLinkage()) {
#if LLVM_VERSION_CODE < LLVM_VERSION(3, 5)
        assert(!Function.hasDLLImportLinkage() &&
               "Found dllimported non-external symbol!");
#else
        assert(!Function.hasDLLImportStorageClass() &&
               "Found dllimported non-external symbol!");
#endif
        DefinedSymbols.insert(Function.getName());
      }
    }
  }

  for (Module::const_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()) {
#if LLVM_VERSION_CODE < LLVM_VERSION(3, 5)
            assert(!I->hasDLLImportLinkage() && "Found dllimported non-external symbol!");
#else
            assert(!I->hasDLLImportStorageClass() && "Found dllimported non-external symbol!");
#endif
        DefinedSymbols.insert(I->getName());
      }
    }

  for (Module::const_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
  // and other symbols we don't want to treat as an undefined symbol
  std::vector<std::string> SymbolsToRemove;
  for (std::set<std::string>::iterator I = UndefinedSymbols.begin();
       I != UndefinedSymbols.end(); ++I )
  {
    if (DefinedSymbols.find(*I) != DefinedSymbols.end()) {
      SymbolsToRemove.push_back(*I);
      continue;
    }

    // Strip out llvm intrinsics
    if ( (I->size() >= llvmIntrinsicPrefix.size() ) &&
       (I->compare(0, llvmIntrinsicPrefix.size(), llvmIntrinsicPrefix) == 0) )
    {
      KLEE_DEBUG_WITH_TYPE("klee_linker", dbgs() << "LLVM intrinsic " << *I <<
                      " has will be removed from undefined symbols"<< "\n");
      SymbolsToRemove.push_back(*I);
      continue;
    }

    // Symbol really is undefined
    KLEE_DEBUG_WITH_TYPE("klee_linker",
                         dbgs() << "Symbol " << *I << " is undefined.\n");
  }

  // Now remove the symbols from undefined set.
  for (auto const &symbol : SymbolsToRemove)
    UndefinedSymbols.erase(symbol);

  KLEE_DEBUG_WITH_TYPE("klee_linker",
                       dbgs() << "*** Finished computing undefined symbols ***\n");
}
예제 #5
0
std::unique_ptr<Module>
llvm::CloneSubModule(const Module &M,
                     HandleGlobalVariableFtor HandleGlobalVariable,
                     HandleFunctionFtor HandleFunction, bool KeepInlineAsm) {

  ValueToValueMapTy VMap;

  // First off, we need to create the new module.
  std::unique_ptr<Module> New =
      llvm::make_unique<Module>(M.getModuleIdentifier(), M.getContext());

  New->setDataLayout(M.getDataLayout());
  New->setTargetTriple(M.getTargetTriple());
  if (KeepInlineAsm)
    New->setModuleInlineAsm(M.getModuleInlineAsm());

  // Copy global variables (but not initializers, yet).
  for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
       I != E; ++I) {
    GlobalVariable *GV = new GlobalVariable(
        *New, I->getType()->getElementType(), I->isConstant(), I->getLinkage(),
        (Constant *)nullptr, I->getName(), (GlobalVariable *)nullptr,
        I->getThreadLocalMode(), I->getType()->getAddressSpace());
    GV->copyAttributesFrom(I);
    VMap[I] = GV;
  }

  // Loop over the functions in the module, making external functions as before
  for (Module::const_iterator I = M.begin(), E = M.end(); I != E; ++I) {
    Function *NF =
        Function::Create(cast<FunctionType>(I->getType()->getElementType()),
                         I->getLinkage(), I->getName(), &*New);
    NF->copyAttributesFrom(I);
    VMap[I] = NF;
  }

  // Loop over the aliases in the module
  for (Module::const_alias_iterator I = M.alias_begin(), E = M.alias_end();
       I != E; ++I) {
    auto *PTy = cast<PointerType>(I->getType());
    auto *GA =
        GlobalAlias::create(PTy->getElementType(), PTy->getAddressSpace(),
                            I->getLinkage(), I->getName(), &*New);
    GA->copyAttributesFrom(I);
    VMap[I] = GA;
  }

  // Now that all of the things that global variable initializer can refer to
  // have been created, loop through and copy the global variable referrers
  // over...  We also set the attributes on the global now.
  for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
       I != E; ++I) {
    GlobalVariable &GV = *cast<GlobalVariable>(VMap[I]);
    HandleGlobalVariable(GV, *I, VMap);
  }

  // Similarly, copy over function bodies now...
  //
  for (Module::const_iterator I = M.begin(), E = M.end(); I != E; ++I) {
    Function &F = *cast<Function>(VMap[I]);
    HandleFunction(F, *I, VMap);
  }

  // And aliases
  for (Module::const_alias_iterator I = M.alias_begin(), E = M.alias_end();
       I != E; ++I) {
    GlobalAlias *GA = cast<GlobalAlias>(VMap[I]);
    if (const Constant *C = I->getAliasee())
      GA->setAliasee(MapValue(C, VMap));
  }

  // And named metadata....
  for (Module::const_named_metadata_iterator I = M.named_metadata_begin(),
                                             E = M.named_metadata_end();
       I != E; ++I) {
    const NamedMDNode &NMD = *I;
    NamedMDNode *NewNMD = New->getOrInsertNamedMetadata(NMD.getName());
    for (unsigned i = 0, e = NMD.getNumOperands(); i != e; ++i)
      NewNMD->addOperand(MapMetadata(NMD.getOperand(i), VMap));
  }

  return New;
}
예제 #6
0
파일: CloneModule.cpp 프로젝트: aosm/clang
Module *llvm::CloneModule(const Module *M,
                          DenseMap<const Value*, Value*> &ValueMap) {
  // First off, we need to create the new module...
  Module *New = new Module(M->getModuleIdentifier());
  New->setDataLayout(M->getDataLayout());
  New->setTargetTriple(M->getTargetTriple());
  New->setModuleInlineAsm(M->getModuleInlineAsm());

  // Copy all of the type symbol table entries over.
  const TypeSymbolTable &TST = M->getTypeSymbolTable();
  for (TypeSymbolTable::const_iterator TI = TST.begin(), TE = TST.end(); 
       TI != TE; ++TI)
    New->addTypeName(TI->first, TI->second);
  
  // Copy all of the dependent libraries over.
  for (Module::lib_iterator I = M->lib_begin(), E = M->lib_end(); I != E; ++I)
    New->addLibrary(*I);

  // Loop over all of the global variables, making corresponding globals in the
  // new module.  Here we add them to the ValueMap and to the new Module.  We
  // don't worry about attributes or initializers, they will come later.
  //
  for (Module::const_global_iterator I = M->global_begin(), E = M->global_end();
       I != E; ++I) {
    GlobalVariable *GV = new GlobalVariable(I->getType()->getElementType(),
                                            false,
                                            GlobalValue::ExternalLinkage, 0,
                                            I->getName(), New);
    GV->setAlignment(I->getAlignment());
    ValueMap[I] = GV;
  }

  // Loop over the functions in the module, making external functions as before
  for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I) {
    Function *NF =
      Function::Create(cast<FunctionType>(I->getType()->getElementType()),
                       GlobalValue::ExternalLinkage, I->getName(), New);
    NF->copyAttributesFrom(I);
    ValueMap[I] = NF;
  }

  // Loop over the aliases in the module
  for (Module::const_alias_iterator I = M->alias_begin(), E = M->alias_end();
       I != E; ++I)
    ValueMap[I] = new GlobalAlias(I->getType(), GlobalAlias::ExternalLinkage,
                                  I->getName(), NULL, New);
  
  // Now that all of the things that global variable initializer can refer to
  // have been created, loop through and copy the global variable referrers
  // over...  We also set the attributes on the global now.
  //
  for (Module::const_global_iterator I = M->global_begin(), E = M->global_end();
       I != E; ++I) {
    GlobalVariable *GV = cast<GlobalVariable>(ValueMap[I]);
    if (I->hasInitializer())
      GV->setInitializer(cast<Constant>(MapValue(I->getInitializer(),
                                                 ValueMap)));
    GV->setLinkage(I->getLinkage());
    GV->setThreadLocal(I->isThreadLocal());
    GV->setConstant(I->isConstant());
  }

  // Similarly, copy over function bodies now...
  //
  for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I) {
    Function *F = cast<Function>(ValueMap[I]);
    if (!I->isDeclaration()) {
      Function::arg_iterator DestI = F->arg_begin();
      for (Function::const_arg_iterator J = I->arg_begin(); J != I->arg_end();
           ++J) {
        DestI->setName(J->getName());
        ValueMap[J] = DestI++;
      }

      std::vector<ReturnInst*> Returns;  // Ignore returns cloned...
      CloneFunctionInto(F, I, ValueMap, Returns);
    }

    F->setLinkage(I->getLinkage());
  }

  // And aliases
  for (Module::const_alias_iterator I = M->alias_begin(), E = M->alias_end();
       I != E; ++I) {
    GlobalAlias *GA = cast<GlobalAlias>(ValueMap[I]);
    GA->setLinkage(I->getLinkage());
    if (const Constant* C = I->getAliasee())
      GA->setAliasee(cast<Constant>(MapValue(C, ValueMap)));
  }
  
  return New;
}
예제 #7
0
Module *llvm::CloneModule(const Module *M,
                          ValueToValueMapTy &VMap) {
  // First off, we need to create the new module...
  Module *New = new Module(M->getModuleIdentifier(), M->getContext());
  New->setDataLayout(M->getDataLayout());
  New->setTargetTriple(M->getTargetTriple());
  New->setModuleInlineAsm(M->getModuleInlineAsm());

  // Copy all of the type symbol table entries over.
  const TypeSymbolTable &TST = M->getTypeSymbolTable();
  for (TypeSymbolTable::const_iterator TI = TST.begin(), TE = TST.end(); 
       TI != TE; ++TI)
    New->addTypeName(TI->first, TI->second);
  
  // Copy all of the dependent libraries over.
  for (Module::lib_iterator I = M->lib_begin(), E = M->lib_end(); I != E; ++I)
    New->addLibrary(*I);

  // Loop over all of the global variables, making corresponding globals in the
  // new module.  Here we add them to the VMap and to the new Module.  We
  // don't worry about attributes or initializers, they will come later.
  //
  for (Module::const_global_iterator I = M->global_begin(), E = M->global_end();
       I != E; ++I) {
    GlobalVariable *GV = new GlobalVariable(*New, 
                                            I->getType()->getElementType(),
                                            false,
                                            GlobalValue::ExternalLinkage, 0,
                                            I->getName());
    GV->setAlignment(I->getAlignment());
    VMap[I] = GV;
  }

  // Loop over the functions in the module, making external functions as before
  for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I) {
    Function *NF =
      Function::Create(cast<FunctionType>(I->getType()->getElementType()),
                       GlobalValue::ExternalLinkage, I->getName(), New);
    NF->copyAttributesFrom(I);
    VMap[I] = NF;
  }

  // Loop over the aliases in the module
  for (Module::const_alias_iterator I = M->alias_begin(), E = M->alias_end();
       I != E; ++I)
    VMap[I] = new GlobalAlias(I->getType(), GlobalAlias::ExternalLinkage,
                                  I->getName(), NULL, New);
  
  // Now that all of the things that global variable initializer can refer to
  // have been created, loop through and copy the global variable referrers
  // over...  We also set the attributes on the global now.
  //
  for (Module::const_global_iterator I = M->global_begin(), E = M->global_end();
       I != E; ++I) {
    GlobalVariable *GV = cast<GlobalVariable>(VMap[I]);
    if (I->hasInitializer())
      GV->setInitializer(cast<Constant>(MapValue(I->getInitializer(),
                                                 VMap)));
    GV->setLinkage(I->getLinkage());
    GV->setThreadLocal(I->isThreadLocal());
    GV->setConstant(I->isConstant());
  }

  // Similarly, copy over function bodies now...
  //
  for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I) {
    Function *F = cast<Function>(VMap[I]);
    if (!I->isDeclaration()) {
      Function::arg_iterator DestI = F->arg_begin();
      for (Function::const_arg_iterator J = I->arg_begin(); J != I->arg_end();
           ++J) {
        DestI->setName(J->getName());
        VMap[J] = DestI++;
      }

      SmallVector<ReturnInst*, 8> Returns;  // Ignore returns cloned.
      CloneFunctionInto(F, I, VMap, Returns);
    }

    F->setLinkage(I->getLinkage());
  }

  // And aliases
  for (Module::const_alias_iterator I = M->alias_begin(), E = M->alias_end();
       I != E; ++I) {
    GlobalAlias *GA = cast<GlobalAlias>(VMap[I]);
    GA->setLinkage(I->getLinkage());
    if (const Constant* C = I->getAliasee())
      GA->setAliasee(cast<Constant>(MapValue(C, VMap)));
  }

  // And named metadata....
  for (Module::const_named_metadata_iterator I = M->named_metadata_begin(),
         E = M->named_metadata_end(); I != E; ++I) {
    const NamedMDNode &NMD = *I;
    SmallVector<MDNode*, 4> MDs;
    for (unsigned i = 0, e = NMD.getNumOperands(); i != e; ++i)
      MDs.push_back(cast<MDNode>(MapValue(NMD.getOperand(i), VMap)));
    NamedMDNode::Create(New->getContext(), NMD.getName(),
                        MDs.data(), MDs.size(), New);
  }

  // Update metadata attach with instructions.
  for (Module::iterator MI = New->begin(), ME = New->end(); MI != ME; ++MI)   
    for (Function::iterator FI = MI->begin(), FE = MI->end(); 
         FI != FE; ++FI)
      for (BasicBlock::iterator BI = FI->begin(), BE = FI->end(); 
           BI != BE; ++BI) {
        SmallVector<std::pair<unsigned, MDNode *>, 4 > MDs;
        BI->getAllMetadata(MDs);
        for (SmallVector<std::pair<unsigned, MDNode *>, 4>::iterator 
               MDI = MDs.begin(), MDE = MDs.end(); MDI != MDE; ++MDI) {
          Value *MappedValue = MapValue(MDI->second, VMap);
          if (MDI->second != MappedValue && MappedValue)
            BI->setMetadata(MDI->first, cast<MDNode>(MappedValue));
        }
      }
  return New;
}