Subversion Repositories QNX 8.QNX8 LLVM/Clang compiler suite

//===- llvm/Module.h - C++ class to represent a VM module -------*- C++ -*-===//

//

// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.

// See https://llvm.org/LICENSE.txt for license information.

// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

//

//===----------------------------------------------------------------------===//

//

/// @file

/// Module.h This file contains the declarations for the Module class.

//

//===----------------------------------------------------------------------===//

#ifndef LLVM_IR_MODULE_H

#define LLVM_IR_MODULE_H

#include "llvm-c/Types.h"

#include "llvm/ADT/STLExtras.h"

#include "llvm/ADT/StringMap.h"

#include "llvm/ADT/StringRef.h"

#include "llvm/ADT/iterator_range.h"

#include "llvm/IR/Attributes.h"

#include "llvm/IR/Comdat.h"

#include "llvm/IR/DataLayout.h"

#include "llvm/IR/Function.h"

#include "llvm/IR/GlobalAlias.h"

#include "llvm/IR/GlobalIFunc.h"

#include "llvm/IR/GlobalVariable.h"

#include "llvm/IR/Metadata.h"

#include "llvm/IR/ProfileSummary.h"

#include "llvm/IR/SymbolTableListTraits.h"

#include "llvm/Support/CBindingWrapping.h"

#include "llvm/Support/CodeGen.h"

#include <cstddef>

#include <cstdint>

#include <iterator>

#include <memory>

#include <optional>

#include <string>

#include <vector>

namespace llvm {

class Error;

class FunctionType;

class GVMaterializer;

class LLVMContext;

class MemoryBuffer;

class ModuleSummaryIndex;

class RandomNumberGenerator;

class StructType;

class VersionTuple;

/// A Module instance is used to store all the information related to an

/// LLVM module. Modules are the top level container of all other LLVM

/// Intermediate Representation (IR) objects. Each module directly contains a

/// list of globals variables, a list of functions, a list of libraries (or

/// other modules) this module depends on, a symbol table, and various data

/// about the target's characteristics.

///

/// A module maintains a GlobalList object that is used to hold all

/// constant references to global variables in the module.  When a global

/// variable is destroyed, it should have no entries in the GlobalList.

/// The main container class for the LLVM Intermediate Representation.

class LLVM_EXTERNAL_VISIBILITY Module {

  /// @name Types And Enumerations

  /// @{

public:

  /// The type for the list of global variables.

  using GlobalListType = SymbolTableList<GlobalVariable>;

  /// The type for the list of functions.

  using FunctionListType = SymbolTableList<Function>;

  /// The type for the list of aliases.

  using AliasListType = SymbolTableList<GlobalAlias>;

  /// The type for the list of ifuncs.

  using IFuncListType = SymbolTableList<GlobalIFunc>;

  /// The type for the list of named metadata.

  using NamedMDListType = ilist<NamedMDNode>;

  /// The type of the comdat "symbol" table.

  using ComdatSymTabType = StringMap<Comdat>;

  /// The type for mapping names to named metadata.

  using NamedMDSymTabType = StringMap<NamedMDNode *>;

  /// The Global Variable iterator.

  using global_iterator = GlobalListType::iterator;

  /// The Global Variable constant iterator.

  using const_global_iterator = GlobalListType::const_iterator;

  /// The Function iterators.

  using iterator = FunctionListType::iterator;

  /// The Function constant iterator

  using const_iterator = FunctionListType::const_iterator;

  /// The Function reverse iterator.

  using reverse_iterator = FunctionListType::reverse_iterator;

  /// The Function constant reverse iterator.

  using const_reverse_iterator = FunctionListType::const_reverse_iterator;

  /// The Global Alias iterators.

  using alias_iterator = AliasListType::iterator;

  /// The Global Alias constant iterator

  using const_alias_iterator = AliasListType::const_iterator;

  /// The Global IFunc iterators.

  using ifunc_iterator = IFuncListType::iterator;

  /// The Global IFunc constant iterator

  using const_ifunc_iterator = IFuncListType::const_iterator;

  /// The named metadata iterators.

  using named_metadata_iterator = NamedMDListType::iterator;

  /// The named metadata constant iterators.

  using const_named_metadata_iterator = NamedMDListType::const_iterator;

  /// This enumeration defines the supported behaviors of module flags.

  enum ModFlagBehavior {

    /// Emits an error if two values disagree, otherwise the resulting value is

    /// that of the operands.

    Error = 1,

    /// Emits a warning if two values disagree. The result value will be the

    /// operand for the flag from the first module being linked.

    Warning = 2,

    /// Adds a requirement that another module flag be present and have a

    /// specified value after linking is performed. The value must be a metadata

    /// pair, where the first element of the pair is the ID of the module flag

    /// to be restricted, and the second element of the pair is the value the

    /// module flag should be restricted to. This behavior can be used to

    /// restrict the allowable results (via triggering of an error) of linking

    /// IDs with the **Override** behavior.

    Require = 3,

    /// Uses the specified value, regardless of the behavior or value of the

    /// other module. If both modules specify **Override**, but the values

    /// differ, an error will be emitted.

    Override = 4,

    /// Appends the two values, which are required to be metadata nodes.

    Append = 5,

    /// Appends the two values, which are required to be metadata

    /// nodes. However, duplicate entries in the second list are dropped

    /// during the append operation.

    AppendUnique = 6,

    /// Takes the max of the two values, which are required to be integers.

    Max = 7,

    /// Takes the min of the two values, which are required to be integers.

    Min = 8,

    // Markers:

    ModFlagBehaviorFirstVal = Error,

    ModFlagBehaviorLastVal = Min

  };

  /// Checks if Metadata represents a valid ModFlagBehavior, and stores the

  /// converted result in MFB.

  static bool isValidModFlagBehavior(Metadata *MD, ModFlagBehavior &MFB);

  /// Check if the given module flag metadata represents a valid module flag,

  /// and store the flag behavior, the key string and the value metadata.

  static bool isValidModuleFlag(const MDNode &ModFlag, ModFlagBehavior &MFB,

                                MDString *&Key, Metadata *&Val);

  struct ModuleFlagEntry {

    ModFlagBehavior Behavior;

    MDString *Key;

    Metadata *Val;

    ModuleFlagEntry(ModFlagBehavior B, MDString *K, Metadata *V)

        : Behavior(B), Key(K), Val(V) {}

  };

/// @}

/// @name Member Variables

/// @{

private:

  LLVMContext &Context;           ///< The LLVMContext from which types and

                                  ///< constants are allocated.

  GlobalListType GlobalList;      ///< The Global Variables in the module

  FunctionListType FunctionList;  ///< The Functions in the module

  AliasListType AliasList;        ///< The Aliases in the module

  IFuncListType IFuncList;        ///< The IFuncs in the module

  NamedMDListType NamedMDList;    ///< The named metadata in the module

  std::string GlobalScopeAsm;     ///< Inline Asm at global scope.

  std::unique_ptr<ValueSymbolTable> ValSymTab; ///< Symbol table for values

  ComdatSymTabType ComdatSymTab;  ///< Symbol table for COMDATs

  std::unique_ptr<MemoryBuffer>

  OwnedMemoryBuffer;              ///< Memory buffer directly owned by this

                                  ///< module, for legacy clients only.

  std::unique_ptr<GVMaterializer>

  Materializer;                   ///< Used to materialize GlobalValues

  std::string ModuleID;           ///< Human readable identifier for the module

  std::string SourceFileName;     ///< Original source file name for module,

                                  ///< recorded in bitcode.

  std::string TargetTriple;       ///< Platform target triple Module compiled on

                                  ///< Format: (arch)(sub)-(vendor)-(sys0-(abi)

  NamedMDSymTabType NamedMDSymTab;  ///< NamedMDNode names.

  DataLayout DL;                  ///< DataLayout associated with the module

  StringMap<unsigned>

      CurrentIntrinsicIds; ///< Keep track of the current unique id count for

                           ///< the specified intrinsic basename.

  DenseMap<std::pair<Intrinsic::ID, const FunctionType *>, unsigned>

      UniquedIntrinsicNames; ///< Keep track of uniqued names of intrinsics

                             ///< based on unnamed types. The combination of

                             ///< ID and FunctionType maps to the extension that

                             ///< is used to make the intrinsic name unique.

  friend class Constant;

/// @}

/// @name Constructors

/// @{

public:

  /// The Module constructor. Note that there is no default constructor. You

  /// must provide a name for the module upon construction.

  explicit Module(StringRef ModuleID, LLVMContext& C);

  /// The module destructor. This will dropAllReferences.

  ~Module();

/// @}

/// @name Module Level Accessors

/// @{

  /// Get the module identifier which is, essentially, the name of the module.

  /// @returns the module identifier as a string

  const std::string &getModuleIdentifier() const { return ModuleID; }

  /// Returns the number of non-debug IR instructions in the module.

  /// This is equivalent to the sum of the IR instruction counts of each

  /// function contained in the module.

  unsigned getInstructionCount() const;

  /// Get the module's original source file name. When compiling from

  /// bitcode, this is taken from a bitcode record where it was recorded.

  /// For other compiles it is the same as the ModuleID, which would

  /// contain the source file name.

  const std::string &getSourceFileName() const { return SourceFileName; }

  /// Get a short "name" for the module.

  ///

  /// This is useful for debugging or logging. It is essentially a convenience

  /// wrapper around getModuleIdentifier().

  StringRef getName() const { return ModuleID; }

  /// Get the data layout string for the module's target platform. This is

  /// equivalent to getDataLayout()->getStringRepresentation().

  const std::string &getDataLayoutStr() const {

    return DL.getStringRepresentation();

  }

  /// Get the data layout for the module's target platform.

  const DataLayout &getDataLayout() const;

  /// Get the target triple which is a string describing the target host.

  /// @returns a string containing the target triple.

  const std::string &getTargetTriple() const { return TargetTriple; }

  /// Get the global data context.

  /// @returns LLVMContext - a container for LLVM's global information

  LLVMContext &getContext() const { return Context; }

  /// Get any module-scope inline assembly blocks.

  /// @returns a string containing the module-scope inline assembly blocks.

  const std::string &getModuleInlineAsm() const { return GlobalScopeAsm; }

  /// Get a RandomNumberGenerator salted for use with this module. The

  /// RNG can be seeded via -rng-seed=<uint64> and is salted with the

  /// ModuleID and the provided pass salt. The returned RNG should not

  /// be shared across threads or passes.

  ///

  /// A unique RNG per pass ensures a reproducible random stream even

  /// when other randomness consuming passes are added or removed. In

  /// addition, the random stream will be reproducible across LLVM

  /// versions when the pass does not change.

  std::unique_ptr<RandomNumberGenerator> createRNG(const StringRef Name) const;

  /// Return true if size-info optimization remark is enabled, false

  /// otherwise.

  bool shouldEmitInstrCountChangedRemark() {

    return getContext().getDiagHandlerPtr()->isAnalysisRemarkEnabled(

        "size-info");

  }

  /// @}

  /// @name Module Level Mutators

  /// @{

  /// Set the module identifier.

  void setModuleIdentifier(StringRef ID) { ModuleID = std::string(ID); }

  /// Set the module's original source file name.

  void setSourceFileName(StringRef Name) { SourceFileName = std::string(Name); }

  /// Set the data layout

  void setDataLayout(StringRef Desc);

  void setDataLayout(const DataLayout &Other);

  /// Set the target triple.

  void setTargetTriple(StringRef T) { TargetTriple = std::string(T); }

  /// Set the module-scope inline assembly blocks.

  /// A trailing newline is added if the input doesn't have one.

  void setModuleInlineAsm(StringRef Asm) {

    GlobalScopeAsm = std::string(Asm);

    if (!GlobalScopeAsm.empty() && GlobalScopeAsm.back() != '\n')

      GlobalScopeAsm += '\n';

  }

  /// Append to the module-scope inline assembly blocks.

  /// A trailing newline is added if the input doesn't have one.

  void appendModuleInlineAsm(StringRef Asm) {

    GlobalScopeAsm += Asm;

    if (!GlobalScopeAsm.empty() && GlobalScopeAsm.back() != '\n')

      GlobalScopeAsm += '\n';

  }

/// @}

/// @name Generic Value Accessors

/// @{

  /// Return the global value in the module with the specified name, of

  /// arbitrary type. This method returns null if a global with the specified

  /// name is not found.

  GlobalValue *getNamedValue(StringRef Name) const;

  /// Return the number of global values in the module.

  unsigned getNumNamedValues() const;

  /// Return a unique non-zero ID for the specified metadata kind. This ID is

  /// uniqued across modules in the current LLVMContext.

  unsigned getMDKindID(StringRef Name) const;

  /// Populate client supplied SmallVector with the name for custom metadata IDs

  /// registered in this LLVMContext.

  void getMDKindNames(SmallVectorImpl<StringRef> &Result) const;

  /// Populate client supplied SmallVector with the bundle tags registered in

  /// this LLVMContext.  The bundle tags are ordered by increasing bundle IDs.

  /// \see LLVMContext::getOperandBundleTagID

  void getOperandBundleTags(SmallVectorImpl<StringRef> &Result) const;

  std::vector<StructType *> getIdentifiedStructTypes() const;

  /// Return a unique name for an intrinsic whose mangling is based on an

  /// unnamed type. The Proto represents the function prototype.

  std::string getUniqueIntrinsicName(StringRef BaseName, Intrinsic::ID Id,

                                     const FunctionType *Proto);

/// @}

/// @name Function Accessors

/// @{

  /// Look up the specified function in the module symbol table. Four

  /// possibilities:

  ///   1. If it does not exist, add a prototype for the function and return it.

  ///   2. Otherwise, if the existing function has the correct prototype, return

  ///      the existing function.

  ///   3. Finally, the function exists but has the wrong prototype: return the

  ///      function with a constantexpr cast to the right prototype.

  ///

  /// In all cases, the returned value is a FunctionCallee wrapper around the

  /// 'FunctionType *T' passed in, as well as a 'Value*' either of the Function or

  /// the bitcast to the function.

  ///

  /// Note: For library calls getOrInsertLibFunc() should be used instead.

  FunctionCallee getOrInsertFunction(StringRef Name, FunctionType *T,

                                     AttributeList AttributeList);

  FunctionCallee getOrInsertFunction(StringRef Name, FunctionType *T);

  /// Look up the specified function in the module symbol table. If it does not

  /// exist, add a prototype for the function and return it. This function

  /// guarantees to return a constant of pointer to the specified function type

  /// or a ConstantExpr BitCast of that type if the named function has a

  /// different type. This version of the method takes a list of

  /// function arguments, which makes it easier for clients to use.

  template <typename... ArgsTy>

  FunctionCallee getOrInsertFunction(StringRef Name,

                                     AttributeList AttributeList, Type *RetTy,

                                     ArgsTy... Args) {

    SmallVector<Type*, sizeof...(ArgsTy)> ArgTys{Args...};

    return getOrInsertFunction(Name,

                               FunctionType::get(RetTy, ArgTys, false),

                               AttributeList);

  }

  /// Same as above, but without the attributes.

  template <typename... ArgsTy>

  FunctionCallee getOrInsertFunction(StringRef Name, Type *RetTy,

                                     ArgsTy... Args) {

    return getOrInsertFunction(Name, AttributeList{}, RetTy, Args...);

  }

  // Avoid an incorrect ordering that'd otherwise compile incorrectly.

  template <typename... ArgsTy>

  FunctionCallee

  getOrInsertFunction(StringRef Name, AttributeList AttributeList,

                      FunctionType *Invalid, ArgsTy... Args) = delete;

  /// Look up the specified function in the module symbol table. If it does not

  /// exist, return null.

  Function *getFunction(StringRef Name) const;

/// @}

/// @name Global Variable Accessors

/// @{

  /// Look up the specified global variable in the module symbol table. If it

  /// does not exist, return null. If AllowInternal is set to true, this

  /// function will return types that have InternalLinkage. By default, these

  /// types are not returned.

  GlobalVariable *getGlobalVariable(StringRef Name) const {

    return getGlobalVariable(Name, false);

  }

  GlobalVariable *getGlobalVariable(StringRef Name, bool AllowInternal) const;

  GlobalVariable *getGlobalVariable(StringRef Name,

                                    bool AllowInternal = false) {

    return static_cast<const Module *>(this)->getGlobalVariable(Name,

                                                                AllowInternal);

  }

  /// Return the global variable in the module with the specified name, of

  /// arbitrary type. This method returns null if a global with the specified

  /// name is not found.

  const GlobalVariable *getNamedGlobal(StringRef Name) const {

    return getGlobalVariable(Name, true);

  }

  GlobalVariable *getNamedGlobal(StringRef Name) {

    return const_cast<GlobalVariable *>(

                       static_cast<const Module *>(this)->getNamedGlobal(Name));

  }

  /// Look up the specified global in the module symbol table.

  /// If it does not exist, invoke a callback to create a declaration of the

  /// global and return it. The global is constantexpr casted to the expected

  /// type if necessary.

  Constant *

  getOrInsertGlobal(StringRef Name, Type *Ty,

                    function_ref<GlobalVariable *()> CreateGlobalCallback);

  /// Look up the specified global in the module symbol table. If required, this

  /// overload constructs the global variable using its constructor's defaults.

  Constant *getOrInsertGlobal(StringRef Name, Type *Ty);

/// @}

/// @name Global Alias Accessors

/// @{

  /// Return the global alias in the module with the specified name, of

  /// arbitrary type. This method returns null if a global with the specified

  /// name is not found.

  GlobalAlias *getNamedAlias(StringRef Name) const;

/// @}

/// @name Global IFunc Accessors

/// @{

  /// Return the global ifunc in the module with the specified name, of

  /// arbitrary type. This method returns null if a global with the specified

  /// name is not found.

  GlobalIFunc *getNamedIFunc(StringRef Name) const;

/// @}

/// @name Named Metadata Accessors

/// @{

  /// Return the first NamedMDNode in the module with the specified name. This

  /// method returns null if a NamedMDNode with the specified name is not found.

  NamedMDNode *getNamedMetadata(const Twine &Name) const;

  /// Return the named MDNode in the module with the specified name. This method

  /// returns a new NamedMDNode if a NamedMDNode with the specified name is not

  /// found.

  NamedMDNode *getOrInsertNamedMetadata(StringRef Name);

  /// Remove the given NamedMDNode from this module and delete it.

  void eraseNamedMetadata(NamedMDNode *NMD);

/// @}

/// @name Comdat Accessors

/// @{

  /// Return the Comdat in the module with the specified name. It is created

  /// if it didn't already exist.

  Comdat *getOrInsertComdat(StringRef Name);

/// @}

/// @name Module Flags Accessors

/// @{

  /// Returns the module flags in the provided vector.

  void getModuleFlagsMetadata(SmallVectorImpl<ModuleFlagEntry> &Flags) const;

  /// Return the corresponding value if Key appears in module flags, otherwise

  /// return null.

  Metadata *getModuleFlag(StringRef Key) const;

  /// Returns the NamedMDNode in the module that represents module-level flags.

  /// This method returns null if there are no module-level flags.

  NamedMDNode *getModuleFlagsMetadata() const;

  /// Returns the NamedMDNode in the module that represents module-level flags.

  /// If module-level flags aren't found, it creates the named metadata that

  /// contains them.

  NamedMDNode *getOrInsertModuleFlagsMetadata();

  /// Add a module-level flag to the module-level flags metadata. It will create

  /// the module-level flags named metadata if it doesn't already exist.

  void addModuleFlag(ModFlagBehavior Behavior, StringRef Key, Metadata *Val);

  void addModuleFlag(ModFlagBehavior Behavior, StringRef Key, Constant *Val);

  void addModuleFlag(ModFlagBehavior Behavior, StringRef Key, uint32_t Val);

  void addModuleFlag(MDNode *Node);

  /// Like addModuleFlag but replaces the old module flag if it already exists.

  void setModuleFlag(ModFlagBehavior Behavior, StringRef Key, Metadata *Val);

  /// @}

  /// @name Materialization

  /// @{

  /// Sets the GVMaterializer to GVM. This module must not yet have a

  /// Materializer. To reset the materializer for a module that already has one,

  /// call materializeAll first. Destroying this module will destroy

  /// its materializer without materializing any more GlobalValues. Without

  /// destroying the Module, there is no way to detach or destroy a materializer

  /// without materializing all the GVs it controls, to avoid leaving orphan

  /// unmaterialized GVs.

  void setMaterializer(GVMaterializer *GVM);

  /// Retrieves the GVMaterializer, if any, for this Module.

  GVMaterializer *getMaterializer() const { return Materializer.get(); }

  bool isMaterialized() const { return !getMaterializer(); }

  /// Make sure the GlobalValue is fully read.

  llvm::Error materialize(GlobalValue *GV);

  /// Make sure all GlobalValues in this Module are fully read and clear the

  /// Materializer.

  llvm::Error materializeAll();

  llvm::Error materializeMetadata();

/// @}

/// @name Direct access to the globals list, functions list, and symbol table

/// @{

  /// Get the Module's list of global variables (constant).

  const GlobalListType   &getGlobalList() const       { return GlobalList; }

  /// Get the Module's list of global variables.

  GlobalListType         &getGlobalList()             { return GlobalList; }

  static GlobalListType Module::*getSublistAccess(GlobalVariable*) {

    return &Module::GlobalList;

  }

  /// Get the Module's list of functions (constant).

  const FunctionListType &getFunctionList() const     { return FunctionList; }

  /// Get the Module's list of functions.

  FunctionListType       &getFunctionList()           { return FunctionList; }

  static FunctionListType Module::*getSublistAccess(Function*) {

    return &Module::FunctionList;

  }

  /// Get the Module's list of aliases (constant).

  const AliasListType    &getAliasList() const        { return AliasList; }

  /// Get the Module's list of aliases.

  AliasListType          &getAliasList()              { return AliasList; }

  static AliasListType Module::*getSublistAccess(GlobalAlias*) {

    return &Module::AliasList;

  }

  /// Get the Module's list of ifuncs (constant).

  const IFuncListType    &getIFuncList() const        { return IFuncList; }

  /// Get the Module's list of ifuncs.

  IFuncListType          &getIFuncList()              { return IFuncList; }

  static IFuncListType Module::*getSublistAccess(GlobalIFunc*) {

    return &Module::IFuncList;

  }

  /// Get the Module's list of named metadata (constant).

  const NamedMDListType  &getNamedMDList() const      { return NamedMDList; }

  /// Get the Module's list of named metadata.

  NamedMDListType        &getNamedMDList()            { return NamedMDList; }

  static NamedMDListType Module::*getSublistAccess(NamedMDNode*) {

    return &Module::NamedMDList;

  }

  /// Get the symbol table of global variable and function identifiers

  const ValueSymbolTable &getValueSymbolTable() const { return *ValSymTab; }

  /// Get the Module's symbol table of global variable and function identifiers.

  ValueSymbolTable       &getValueSymbolTable()       { return *ValSymTab; }

  /// Get the Module's symbol table for COMDATs (constant).

  const ComdatSymTabType &getComdatSymbolTable() const { return ComdatSymTab; }

  /// Get the Module's symbol table for COMDATs.

  ComdatSymTabType &getComdatSymbolTable() { return ComdatSymTab; }

/// @}

/// @name Global Variable Iteration

/// @{

  global_iterator       global_begin()       { return GlobalList.begin(); }

  const_global_iterator global_begin() const { return GlobalList.begin(); }

  global_iterator       global_end  ()       { return GlobalList.end(); }

  const_global_iterator global_end  () const { return GlobalList.end(); }

  size_t                global_size () const { return GlobalList.size(); }

  bool                  global_empty() const { return GlobalList.empty(); }

  iterator_range<global_iterator> globals() {

    return make_range(global_begin(), global_end());

  }

  iterator_range<const_global_iterator> globals() const {

    return make_range(global_begin(), global_end());

  }

/// @}

/// @name Function Iteration

/// @{

  iterator                begin()       { return FunctionList.begin(); }

  const_iterator          begin() const { return FunctionList.begin(); }

  iterator                end  ()       { return FunctionList.end();   }

  const_iterator          end  () const { return FunctionList.end();   }

  reverse_iterator        rbegin()      { return FunctionList.rbegin(); }

  const_reverse_iterator  rbegin() const{ return FunctionList.rbegin(); }

  reverse_iterator        rend()        { return FunctionList.rend(); }

  const_reverse_iterator  rend() const  { return FunctionList.rend(); }

  size_t                  size() const  { return FunctionList.size(); }

  bool                    empty() const { return FunctionList.empty(); }

  iterator_range<iterator> functions() {

    return make_range(begin(), end());

  }

  iterator_range<const_iterator> functions() const {

    return make_range(begin(), end());

  }

/// @}

/// @name Alias Iteration

/// @{

  alias_iterator       alias_begin()            { return AliasList.begin(); }

  const_alias_iterator alias_begin() const      { return AliasList.begin(); }

  alias_iterator       alias_end  ()            { return AliasList.end();   }

  const_alias_iterator alias_end  () const      { return AliasList.end();   }

  size_t               alias_size () const      { return AliasList.size();  }

  bool                 alias_empty() const      { return AliasList.empty(); }

  iterator_range<alias_iterator> aliases() {

    return make_range(alias_begin(), alias_end());

  }

  iterator_range<const_alias_iterator> aliases() const {

    return make_range(alias_begin(), alias_end());

  }

/// @}

/// @name IFunc Iteration

/// @{

  ifunc_iterator       ifunc_begin()            { return IFuncList.begin(); }

  const_ifunc_iterator ifunc_begin() const      { return IFuncList.begin(); }

  ifunc_iterator       ifunc_end  ()            { return IFuncList.end();   }

  const_ifunc_iterator ifunc_end  () const      { return IFuncList.end();   }

  size_t               ifunc_size () const      { return IFuncList.size();  }

  bool                 ifunc_empty() const      { return IFuncList.empty(); }

  iterator_range<ifunc_iterator> ifuncs() {

    return make_range(ifunc_begin(), ifunc_end());

  }

  iterator_range<const_ifunc_iterator> ifuncs() const {

    return make_range(ifunc_begin(), ifunc_end());

  }

  /// @}

  /// @name Convenience iterators

  /// @{

  using global_object_iterator =

      concat_iterator<GlobalObject, iterator, global_iterator>;

  using const_global_object_iterator =

      concat_iterator<const GlobalObject, const_iterator,

                      const_global_iterator>;

  iterator_range<global_object_iterator> global_objects();

  iterator_range<const_global_object_iterator> global_objects() const;

  using global_value_iterator =

      concat_iterator<GlobalValue, iterator, global_iterator, alias_iterator,

                      ifunc_iterator>;

  using const_global_value_iterator =

      concat_iterator<const GlobalValue, const_iterator, const_global_iterator,

                      const_alias_iterator, const_ifunc_iterator>;

  iterator_range<global_value_iterator> global_values();

  iterator_range<const_global_value_iterator> global_values() const;

  /// @}

  /// @name Named Metadata Iteration

  /// @{

  named_metadata_iterator named_metadata_begin() { return NamedMDList.begin(); }

  const_named_metadata_iterator named_metadata_begin() const {

    return NamedMDList.begin();

  }

  named_metadata_iterator named_metadata_end() { return NamedMDList.end(); }

  const_named_metadata_iterator named_metadata_end() const {

    return NamedMDList.end();

  }

  size_t named_metadata_size() const { return NamedMDList.size();  }

  bool named_metadata_empty() const { return NamedMDList.empty(); }

  iterator_range<named_metadata_iterator> named_metadata() {

    return make_range(named_metadata_begin(), named_metadata_end());

  }

  iterator_range<const_named_metadata_iterator> named_metadata() const {

    return make_range(named_metadata_begin(), named_metadata_end());

  }

  /// An iterator for DICompileUnits that skips those marked NoDebug.

  class debug_compile_units_iterator {

    NamedMDNode *CUs;

    unsigned Idx;

    void SkipNoDebugCUs();

  public:

    using iterator_category = std::input_iterator_tag;

    using value_type = DICompileUnit *;

    using difference_type = std::ptrdiff_t;

    using pointer = value_type *;

    using reference = value_type &;

    explicit debug_compile_units_iterator(NamedMDNode *CUs, unsigned Idx)

        : CUs(CUs), Idx(Idx) {

      SkipNoDebugCUs();

    }

    debug_compile_units_iterator &operator++() {

      ++Idx;

      SkipNoDebugCUs();

      return *this;

    }

    debug_compile_units_iterator operator++(int) {

      debug_compile_units_iterator T(*this);

      ++Idx;

      return T;

    }

    bool operator==(const debug_compile_units_iterator &I) const {

      return Idx == I.Idx;

    }

    bool operator!=(const debug_compile_units_iterator &I) const {

      return Idx != I.Idx;

    }

    DICompileUnit *operator*() const;

    DICompileUnit *operator->() const;

  };

  debug_compile_units_iterator debug_compile_units_begin() const {

    auto *CUs = getNamedMetadata("llvm.dbg.cu");

    return debug_compile_units_iterator(CUs, 0);

  }

  debug_compile_units_iterator debug_compile_units_end() const {

    auto *CUs = getNamedMetadata("llvm.dbg.cu");

    return debug_compile_units_iterator(CUs, CUs ? CUs->getNumOperands() : 0);

  }

  /// Return an iterator for all DICompileUnits listed in this Module's

  /// llvm.dbg.cu named metadata node and aren't explicitly marked as

  /// NoDebug.

  iterator_range<debug_compile_units_iterator> debug_compile_units() const {

    auto *CUs = getNamedMetadata("llvm.dbg.cu");

    return make_range(

        debug_compile_units_iterator(CUs, 0),

        debug_compile_units_iterator(CUs, CUs ? CUs->getNumOperands() : 0));

  }

/// @}

  /// Destroy ConstantArrays in LLVMContext if they are not used.

  /// ConstantArrays constructed during linking can cause quadratic memory

  /// explosion. Releasing all unused constants can cause a 20% LTO compile-time

  /// slowdown for a large application.

  ///

  /// NOTE: Constants are currently owned by LLVMContext. This can then only

  /// be called where all uses of the LLVMContext are understood.

  void dropTriviallyDeadConstantArrays();

/// @name Utility functions for printing and dumping Module objects

/// @{

  /// Print the module to an output stream with an optional

  /// AssemblyAnnotationWriter.  If \c ShouldPreserveUseListOrder, then include

  /// uselistorder directives so that use-lists can be recreated when reading

  /// the assembly.

  void print(raw_ostream &OS, AssemblyAnnotationWriter *AAW,

             bool ShouldPreserveUseListOrder = false,

             bool IsForDebug = false) const;

  /// Dump the module to stderr (for debugging).

  void dump() const;

  /// This function causes all the subinstructions to "let go" of all references

  /// that they are maintaining.  This allows one to 'delete' a whole class at

  /// a time, even though there may be circular references... first all

  /// references are dropped, and all use counts go to zero.  Then everything

  /// is delete'd for real.  Note that no operations are valid on an object

  /// that has "dropped all references", except operator delete.

  void dropAllReferences();

/// @}

/// @name Utility functions for querying Debug information.

/// @{

  /// Returns the Number of Register ParametersDwarf Version by checking

  /// module flags.

  unsigned getNumberRegisterParameters() const;

  /// Returns the Dwarf Version by checking module flags.

  unsigned getDwarfVersion() const;

  /// Returns the DWARF format by checking module flags.

  bool isDwarf64() const;