// run - This incorporates all types used by the specified module
//
bool FindUsedTypes::runOnModule(Module &m) {
  UsedTypes.clear();  // reset if run multiple times...

  // Loop over global variables, incorporating their types
  for (Module::const_global_iterator I = m.global_begin(), E = m.global_end();
       I != E; ++I) {
    IncorporateType(I->getType());
    if (I->hasInitializer())
      IncorporateValue(I->getInitializer());
  }

  for (Module::iterator MI = m.begin(), ME = m.end(); MI != ME; ++MI) {
    IncorporateType(MI->getType());
    const Function &F = *MI;

    // Loop over all of the instructions in the function, adding their return
    // type as well as the types of their operands.
    //
    for (const_inst_iterator II = inst_begin(F), IE = inst_end(F);
         II != IE; ++II) {
      const Instruction &I = *II;

      IncorporateType(I.getType());  // Incorporate the type of the instruction
      for (User::const_op_iterator OI = I.op_begin(), OE = I.op_end();
           OI != OE; ++OI)
        IncorporateValue(*OI);  // Insert inst operand types as well
    }
  }

  return false;
}

 virtual bool runOnModule(Module &M) {
   for (Module::const_global_iterator GI = M.global_begin(),
                                      GE = M.global_end();
        GI != GE; ++GI) {
     outs() << "Found global named \"" << GI->getName()
            << "\": type = " << LLVMTypeAsString(GI->getType()) << "\n";
   }
   return false;
 }

// linkGlobalInits - Update the initializers in the Dest module now that all
// globals that may be referenced are in Dest.
void ModuleLinker::linkGlobalInits() {
  // Loop over all of the globals in the src module, mapping them over as we go
  for (Module::const_global_iterator I = SrcM->global_begin(),
       E = SrcM->global_end(); I != E; ++I) {
    
    // Only process initialized GV's or ones not already in dest.
    if (!I->hasInitializer() || DoNotLinkFromSource.count(I)) continue;          
    
    // Grab destination global variable.
    GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[I]);
    // Figure out what the initializer looks like in the dest module.
    DGV->setInitializer(MapValue(I->getInitializer(), ValueMap,
                                 RF_None, &TypeMap));
  }
}

// Emit global variables.
static void WriteGlobalVars(const Module *M,
                            const NaClValueEnumerator &VE,
                            NaClBitstreamWriter &Stream) {
  Stream.EnterSubblock(naclbitc::GLOBALVAR_BLOCK_ID);
  SmallVector<uint32_t, 32> Vals;
  unsigned GlobalVarID = VE.getFirstGlobalVarID();

  // Emit the number of global variables.

  Vals.push_back(M->getGlobalList().size());
  Stream.EmitRecord(naclbitc::GLOBALVAR_COUNT, Vals);
  Vals.clear();

  // Now emit each global variable.
  for (Module::const_global_iterator
           GV = M->global_begin(), E = M->global_end();
       GV != E; ++GV, ++GlobalVarID) {
    // Define the global variable.
    Vals.push_back(Log2_32(GV->getAlignment()) + 1);
    Vals.push_back(GV->isConstant());
    Stream.EmitRecord(naclbitc::GLOBALVAR_VAR, Vals, GLOBALVAR_VAR_ABBREV);
    Vals.clear();

    // Add the field(s).
    const Constant *C = GV->getInitializer();
    if (C == 0)
      report_fatal_error("Global variable initializer not a constant");
    if (const ConstantStruct *CS = dyn_cast<ConstantStruct>(C)) {
      if (!CS->getType()->isPacked())
        report_fatal_error("Global variable type not packed");
      if (CS->getType()->hasName())
        report_fatal_error("Global variable type is named");
      Vals.push_back(CS->getNumOperands());
      Stream.EmitRecord(naclbitc::GLOBALVAR_COMPOUND, Vals,
                        GLOBALVAR_COMPOUND_ABBREV);
      Vals.clear();
      for (unsigned I = 0; I < CS->getNumOperands(); ++I) {
        WriteGlobalInit(dyn_cast<Constant>(CS->getOperand(I)), GlobalVarID,
                        Vals, VE, Stream);
      }
    } else {
      WriteGlobalInit(C, GlobalVarID, Vals, VE, Stream);
    }
  }

  assert(GlobalVarID == VE.getFirstGlobalVarID() + VE.getNumGlobalVarIDs());
  Stream.ExitBlock();
}

bool MementosSizeGlobals::runOnModule (Module &M) {
  TD = getAnalysisIfAvailable<DataLayout>();
  for (Module::const_global_iterator i = M.global_begin();
      i != M.global_end(); ++i) {
    Type *T = i->getType()->getElementType();
    const unsigned int bytes = TD->getTypeAllocSize(T);
    const StringRef s = i->getName();
    DEBUG(outs() << "Found a global of size " << bytes << " (" << s << ")\n");
    if (shouldSkipGlobal(s)) {
      DEBUG(outs() << "Skipping global \"" << s << "\"\n");
    } else {
      TotalSizeInBytes += bytes;
    }
  }
  NumBytesRequired += TotalSizeInBytes;
  return false; // have not modified the module
}

void TypeFinder::Run(const Module &M) {

	AddModuleTypesToPrinter(TP,&M);

    // Get types from the type symbol table.  This gets opaque types referened
    // only through derived named types.
    const TypeSymbolTable &ST = M.getTypeSymbolTable();
    for (TypeSymbolTable::const_iterator TI = ST.begin(), E = ST.end();
           TI != E; ++TI)
		IncorporateType(TI->second);

    // Get types from global variables.
	for (Module::const_global_iterator I = M.global_begin(),
           E = M.global_end(); I != E; ++I) {
        IncorporateType(I->getType());
        if (I->hasInitializer())
          IncorporateValue(I->getInitializer());
    }

    // Get types from aliases.
    for (Module::const_alias_iterator I = M.alias_begin(),
         E = M.alias_end(); I != E; ++I) {
		IncorporateType(I->getType());
        IncorporateValue(I->getAliasee());
    }

    // Get types from functions.
    for (Module::const_iterator FI = M.begin(), E = M.end(); FI != E; ++FI) {
        IncorporateType(FI->getType());

		for (Function::const_iterator BB = FI->begin(), E = FI->end();
             BB != E;++BB)
			for (BasicBlock::const_iterator II = BB->begin(),
               E = BB->end(); II != E; ++II) {
				const Instruction &I = *II;
				// Incorporate the type of the instruction and all its operands.
				IncorporateType(I.getType());
				for (User::const_op_iterator OI = I.op_begin(), OE = I.op_end();
					OI != OE; ++OI)
					IncorporateValue(*OI);
			}
      }
}

bool X86IntelAsmPrinter::doInitialization(Module &M) {
  bool Result = AsmPrinter::doInitialization(M);

  Mang->markCharUnacceptable('.');

  O << "\t.686\n\t.model flat\n\n";

  // Emit declarations for external functions.
  for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
    if (I->isDeclaration()) {
      std::string Name = Mang->getValueName(I);
      decorateName(Name, I);

      O << "\textern " ;
      if (I->hasDLLImportLinkage()) {
        O << "__imp_";
      }
      O << Name << ":near\n";
    }

  // Emit declarations for external globals.  Note that VC++ always declares
  // external globals to have type byte, and if that's good enough for VC++...
  for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
       I != E; ++I) {
    if (I->isDeclaration()) {
      std::string Name = Mang->getValueName(I);

      O << "\textern " ;
      if (I->hasDLLImportLinkage()) {
        O << "__imp_";
      }
      O << Name << ":byte\n";
    }
  }

  return Result;
}

void PIC16AsmPrinter::EmitExternsAndGlobals (Module &M) {
 // Emit declarations for external functions.
  O << "section.0" <<"\n";
  for (Module::iterator I = M.begin(), E = M.end(); I != E; I++) {
    std::string Name = Mang->getValueName(I);
    if (Name.compare("abort") == 0)
      continue;
    if (I->isDeclaration()) {
      O << "\textern " <<Name << "\n";
      O << "\textern " << Name << ".retval\n";
      O << "\textern " << Name << ".args\n";
    }
    else if (I->hasExternalLinkage()) {
      O << "\tglobal " << Name << "\n";
      O << "\tglobal " << Name << ".retval\n";
      O << "\tglobal " << Name << ".args\n";
    }
  }

  // Emit header file to include declaration of library functions
  O << "\t#include C16IntrinsicCalls.INC\n";

  // Emit declarations for external globals.
  for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
       I != E; I++) {
    // Any variables reaching here with ".auto." in its name is a local scope
    // variable and should not be printed in global data section.
    std::string Name = Mang->getValueName(I);
    if (isLocalName (Name))
      continue;

    if (I->isDeclaration())
      O << "\textern "<< Name << "\n";
    else if (I->hasCommonLinkage() || I->hasExternalLinkage())
      O << "\tglobal "<< Name << "\n";
  }
}

bool SparcAsmPrinter::doFinalization(Module &M) {
  const TargetData *TD = TM.getTargetData();

  // Print out module-level global variables here.
  for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
       I != E; ++I)
    if (I->hasInitializer()) {   // External global require no code
      // Check to see if this is a special global used by LLVM, if so, emit it.
      if (EmitSpecialLLVMGlobal(I))
        continue;
      
      O << "\n\n";
      std::string name = Mang->getValueName(I);
      Constant *C = I->getInitializer();
      unsigned Size = TD->getABITypeSize(C->getType());
      unsigned Align = TD->getPreferredAlignment(I);

      if (C->isNullValue() &&
          (I->hasLinkOnceLinkage() || I->hasInternalLinkage() ||
           I->hasWeakLinkage() /* FIXME: Verify correct */)) {
        SwitchToDataSection(".data", I);
        if (I->hasInternalLinkage())
          O << "\t.local " << name << "\n";

        O << "\t.comm " << name << "," << TD->getABITypeSize(C->getType())
          << "," << Align;
        O << "\n";
      } else {
        switch (I->getLinkage()) {
        case GlobalValue::LinkOnceLinkage:
        case GlobalValue::WeakLinkage:   // FIXME: Verify correct for weak.
          // Nonnull linkonce -> weak
          O << "\t.weak " << name << "\n";
          SwitchToDataSection("", I);
          O << "\t.section\t\".llvm.linkonce.d." << name
            << "\",\"aw\",@progbits\n";
          break;

        case GlobalValue::AppendingLinkage:
          // FIXME: appending linkage variables should go into a section of
          // their name or something.  For now, just emit them as external.
        case GlobalValue::ExternalLinkage:
          // If external or appending, declare as a global symbol
          O << "\t.globl " << name << "\n";
          // FALL THROUGH
        case GlobalValue::InternalLinkage:
          if (C->isNullValue())
            SwitchToDataSection(".bss", I);
          else
            SwitchToDataSection(".data", I);
          break;
        case GlobalValue::GhostLinkage:
          cerr << "Should not have any unmaterialized functions!\n";
          abort();
        case GlobalValue::DLLImportLinkage:
          cerr << "DLLImport linkage is not supported by this target!\n";
          abort();
        case GlobalValue::DLLExportLinkage:
          cerr << "DLLExport linkage is not supported by this target!\n";
          abort();
        default:
          assert(0 && "Unknown linkage type!");          
        }

        O << "\t.align " << Align << "\n";
        O << "\t.type " << name << ",#object\n";
        O << "\t.size " << name << "," << Size << "\n";
        O << name << ":\n";
        EmitGlobalConstant(C);
      }
    }

  return AsmPrinter::doFinalization(M);
}

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;
}

/// EmitGlobals - Emit all of the global variables to memory, storing their
/// addresses into GlobalAddress.  This must make sure to copy the contents of
/// their initializers into the memory.
///
void ExecutionEngine::emitGlobals() {

  // Loop over all of the global variables in the program, allocating the memory
  // to hold them.  If there is more than one module, do a prepass over globals
  // to figure out how the different modules should link together.
  //
  std::map<std::pair<std::string, const Type*>,
           const GlobalValue*> LinkedGlobalsMap;

  if (Modules.size() != 1) {
    for (unsigned m = 0, e = Modules.size(); m != e; ++m) {
      Module &M = *Modules[m]->getModule();
      for (Module::const_global_iterator I = M.global_begin(),
           E = M.global_end(); I != E; ++I) {
        const GlobalValue *GV = I;
        if (GV->hasLocalLinkage() || GV->isDeclaration() ||
            GV->hasAppendingLinkage() || !GV->hasName())
          continue;// Ignore external globals and globals with internal linkage.
          
        const GlobalValue *&GVEntry = 
          LinkedGlobalsMap[std::make_pair(GV->getName(), GV->getType())];

        // If this is the first time we've seen this global, it is the canonical
        // version.
        if (!GVEntry) {
          GVEntry = GV;
          continue;
        }
        
        // If the existing global is strong, never replace it.
        if (GVEntry->hasExternalLinkage() ||
            GVEntry->hasDLLImportLinkage() ||
            GVEntry->hasDLLExportLinkage())
          continue;
        
        // Otherwise, we know it's linkonce/weak, replace it if this is a strong
        // symbol.  FIXME is this right for common?
        if (GV->hasExternalLinkage() || GVEntry->hasExternalWeakLinkage())
          GVEntry = GV;
      }
    }
  }
  
  std::vector<const GlobalValue*> NonCanonicalGlobals;
  for (unsigned m = 0, e = Modules.size(); m != e; ++m) {
    Module &M = *Modules[m]->getModule();
    for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
         I != E; ++I) {
      // In the multi-module case, see what this global maps to.
      if (!LinkedGlobalsMap.empty()) {
        if (const GlobalValue *GVEntry = 
              LinkedGlobalsMap[std::make_pair(I->getName(), I->getType())]) {
          // If something else is the canonical global, ignore this one.
          if (GVEntry != &*I) {
            NonCanonicalGlobals.push_back(I);
            continue;
          }
        }
      }
      
      if (!I->isDeclaration()) {
        addGlobalMapping(I, getMemoryForGV(I));
      } else {
        // External variable reference. Try to use the dynamic loader to
        // get a pointer to it.
        if (void *SymAddr =
            sys::DynamicLibrary::SearchForAddressOfSymbol(I->getName().c_str()))
          addGlobalMapping(I, SymAddr);
        else {
          cerr << "Could not resolve external global address: "
               << I->getName() << "\n";
          abort();
        }
      }
    }
    
    // If there are multiple modules, map the non-canonical globals to their
    // canonical location.
    if (!NonCanonicalGlobals.empty()) {
      for (unsigned i = 0, e = NonCanonicalGlobals.size(); i != e; ++i) {
        const GlobalValue *GV = NonCanonicalGlobals[i];
        const GlobalValue *CGV =
          LinkedGlobalsMap[std::make_pair(GV->getName(), GV->getType())];
        void *Ptr = getPointerToGlobalIfAvailable(CGV);
        assert(Ptr && "Canonical global wasn't codegen'd!");
        addGlobalMapping(GV, Ptr);
      }
    }
    
    // Now that all of the globals are set up in memory, loop through them all 
    // and initialize their contents.
    for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
         I != E; ++I) {
      if (!I->isDeclaration()) {
        if (!LinkedGlobalsMap.empty()) {
          if (const GlobalValue *GVEntry = 
//.........这里部分代码省略.........

/// ValueEnumerator - Enumerate module-level information.
ValueEnumerator::ValueEnumerator(const Module *M) {
  // Enumerate the global variables.
  for (Module::const_global_iterator I = M->global_begin(),
         E = M->global_end(); I != E; ++I)
    EnumerateValue(I);

  // Enumerate the functions.
  for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I) {
    EnumerateValue(I);
    EnumerateAttributes(cast<Function>(I)->getAttributes());
  }

  // Enumerate the aliases.
  for (Module::const_alias_iterator I = M->alias_begin(), E = M->alias_end();
       I != E; ++I)
    EnumerateValue(I);

  // Remember what is the cutoff between globalvalue's and other constants.
  unsigned FirstConstant = Values.size();

  // Enumerate the global variable initializers.
  for (Module::const_global_iterator I = M->global_begin(),
         E = M->global_end(); I != E; ++I)
    if (I->hasInitializer())
      EnumerateValue(I->getInitializer());

  // Enumerate the aliasees.
  for (Module::const_alias_iterator I = M->alias_begin(), E = M->alias_end();
       I != E; ++I)
    EnumerateValue(I->getAliasee());

  // Insert constants and metadata that are named at module level into the slot
  // pool so that the module symbol table can refer to them...
  EnumerateValueSymbolTable(M->getValueSymbolTable());
  EnumerateNamedMetadata(M);

  SmallVector<std::pair<unsigned, MDNode*>, 8> MDs;

  // Enumerate types used by function bodies and argument lists.
  for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {

    for (Function::const_arg_iterator I = F->arg_begin(), E = F->arg_end();
         I != E; ++I)
      EnumerateType(I->getType());

    for (Function::const_iterator BB = F->begin(), E = F->end(); BB != E; ++BB)
      for (BasicBlock::const_iterator I = BB->begin(), E = BB->end(); I!=E;++I){
        for (User::const_op_iterator OI = I->op_begin(), E = I->op_end();
             OI != E; ++OI) {
          if (MDNode *MD = dyn_cast<MDNode>(*OI))
            if (MD->isFunctionLocal() && MD->getFunction())
              // These will get enumerated during function-incorporation.
              continue;
          EnumerateOperandType(*OI);
        }
        EnumerateType(I->getType());
        if (const CallInst *CI = dyn_cast<CallInst>(I))
          EnumerateAttributes(CI->getAttributes());
        else if (const InvokeInst *II = dyn_cast<InvokeInst>(I))
          EnumerateAttributes(II->getAttributes());

        // Enumerate metadata attached with this instruction.
        MDs.clear();
        I->getAllMetadataOtherThanDebugLoc(MDs);
        for (unsigned i = 0, e = MDs.size(); i != e; ++i)
          EnumerateMetadata(MDs[i].second);

        if (!I->getDebugLoc().isUnknown()) {
          MDNode *Scope, *IA;
          I->getDebugLoc().getScopeAndInlinedAt(Scope, IA, I->getContext());
          if (Scope) EnumerateMetadata(Scope);
          if (IA) EnumerateMetadata(IA);
        }
      }
  }

  // Optimize constant ordering.
  OptimizeConstants(FirstConstant, Values.size());
}

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());
  }
}

ValueEnumerator::ValueEnumerator(const Module &M,
                                 bool ShouldPreserveUseListOrder)
    : HasMDString(false), HasDILocation(false), HasGenericDINode(false),
      ShouldPreserveUseListOrder(ShouldPreserveUseListOrder) {
  if (ShouldPreserveUseListOrder)
    UseListOrders = predictUseListOrder(M);

  // Enumerate the global variables.
  for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
       I != E; ++I)
    EnumerateValue(I);

  // Enumerate the functions.
  for (Module::const_iterator I = M.begin(), E = M.end(); I != E; ++I) {
    EnumerateValue(I);
    EnumerateAttributes(cast<Function>(I)->getAttributes());
  }

  // Enumerate the aliases.
  for (Module::const_alias_iterator I = M.alias_begin(), E = M.alias_end();
       I != E; ++I)
    EnumerateValue(I);

  // Remember what is the cutoff between globalvalue's and other constants.
  unsigned FirstConstant = Values.size();

  // Enumerate the global variable initializers.
  for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
       I != E; ++I)
    if (I->hasInitializer())
      EnumerateValue(I->getInitializer());

  // Enumerate the aliasees.
  for (Module::const_alias_iterator I = M.alias_begin(), E = M.alias_end();
       I != E; ++I)
    EnumerateValue(I->getAliasee());

  // Enumerate the prefix data constants.
  for (Module::const_iterator I = M.begin(), E = M.end(); I != E; ++I)
    if (I->hasPrefixData())
      EnumerateValue(I->getPrefixData());

  // Enumerate the prologue data constants.
  for (Module::const_iterator I = M.begin(), E = M.end(); I != E; ++I)
    if (I->hasPrologueData())
      EnumerateValue(I->getPrologueData());

  // Enumerate the metadata type.
  //
  // TODO: Move this to ValueEnumerator::EnumerateOperandType() once bitcode
  // only encodes the metadata type when it's used as a value.
  EnumerateType(Type::getMetadataTy(M.getContext()));

  // Insert constants and metadata that are named at module level into the slot
  // pool so that the module symbol table can refer to them...
  EnumerateValueSymbolTable(M.getValueSymbolTable());
  EnumerateNamedMetadata(M);

  SmallVector<std::pair<unsigned, MDNode *>, 8> MDs;

  // Enumerate types used by function bodies and argument lists.
  for (const Function &F : M) {
    for (const Argument &A : F.args())
      EnumerateType(A.getType());

    // Enumerate metadata attached to this function.
    F.getAllMetadata(MDs);
    for (const auto &I : MDs)
      EnumerateMetadata(I.second);

    for (const BasicBlock &BB : F)
      for (const Instruction &I : BB) {
        for (const Use &Op : I.operands()) {
          auto *MD = dyn_cast<MetadataAsValue>(&Op);
          if (!MD) {
            EnumerateOperandType(Op);
            continue;
          }

          // Local metadata is enumerated during function-incorporation.
          if (isa<LocalAsMetadata>(MD->getMetadata()))
            continue;

          EnumerateMetadata(MD->getMetadata());
        }
        EnumerateType(I.getType());
        if (const CallInst *CI = dyn_cast<CallInst>(&I))
          EnumerateAttributes(CI->getAttributes());
        else if (const InvokeInst *II = dyn_cast<InvokeInst>(&I))
          EnumerateAttributes(II->getAttributes());

        // Enumerate metadata attached with this instruction.
        MDs.clear();
        I.getAllMetadataOtherThanDebugLoc(MDs);
        for (unsigned i = 0, e = MDs.size(); i != e; ++i)
          EnumerateMetadata(MDs[i].second);

        // Don't enumerate the location directly -- it has a special record
        // type -- but enumerate its operands.
        if (DILocation *L = I.getDebugLoc())
//.........这里部分代码省略.........

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;
}

/// ValueEnumerator - Enumerate module-level information.
ValueEnumerator::ValueEnumerator(const Module *M) {
  // Enumerate the global variables.
  for (Module::const_global_iterator I = M->global_begin(),
         E = M->global_end(); I != E; ++I)
    EnumerateValue(I);

  // Enumerate the functions.
  for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I) {
    EnumerateValue(I);
    EnumerateParamAttrs(cast<Function>(I)->getParamAttrs());
  }

  // Enumerate the aliases.
  for (Module::const_alias_iterator I = M->alias_begin(), E = M->alias_end();
       I != E; ++I)
    EnumerateValue(I);
  
  // Remember what is the cutoff between globalvalue's and other constants.
  unsigned FirstConstant = Values.size();
  
  // Enumerate the global variable initializers.
  for (Module::const_global_iterator I = M->global_begin(),
         E = M->global_end(); I != E; ++I)
    if (I->hasInitializer())
      EnumerateValue(I->getInitializer());

  // Enumerate the aliasees.
  for (Module::const_alias_iterator I = M->alias_begin(), E = M->alias_end();
       I != E; ++I)
    EnumerateValue(I->getAliasee());
  
  // Enumerate types used by the type symbol table.
  EnumerateTypeSymbolTable(M->getTypeSymbolTable());

  // Insert constants that are named at module level into the slot pool so that
  // the module symbol table can refer to them...
  EnumerateValueSymbolTable(M->getValueSymbolTable());
  
  // Enumerate types used by function bodies and argument lists.
  for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
    
    for (Function::const_arg_iterator I = F->arg_begin(), E = F->arg_end();
         I != E; ++I)
      EnumerateType(I->getType());
    
    for (Function::const_iterator BB = F->begin(), E = F->end(); BB != E; ++BB)
      for (BasicBlock::const_iterator I = BB->begin(), E = BB->end(); I!=E;++I){
        for (User::const_op_iterator OI = I->op_begin(), E = I->op_end(); 
             OI != E; ++OI)
          EnumerateOperandType(*OI);
        EnumerateType(I->getType());
        if (const CallInst *CI = dyn_cast<CallInst>(I))
          EnumerateParamAttrs(CI->getParamAttrs());
        else if (const InvokeInst *II = dyn_cast<InvokeInst>(I))
          EnumerateParamAttrs(II->getParamAttrs());
      }
  }
  
  // Optimize constant ordering.
  OptimizeConstants(FirstConstant, Values.size());
    
  // Sort the type table by frequency so that most commonly used types are early
  // in the table (have low bit-width).
  std::stable_sort(Types.begin(), Types.end(), CompareByFrequency);
    
  // Partition the Type ID's so that the first-class types occur before the
  // aggregate types.  This allows the aggregate types to be dropped from the
  // type table after parsing the global variable initializers.
  std::partition(Types.begin(), Types.end(), isFirstClassType);

  // Now that we rearranged the type table, rebuild TypeMap.
  for (unsigned i = 0, e = Types.size(); i != e; ++i)
    TypeMap[Types[i].first] = i+1;
}

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()),