GlobalAlias.h revision 360784 
1//===-------- llvm/GlobalAlias.h - GlobalAlias class ------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file contains the declaration of the GlobalAlias class, which
10// represents a single function or variable alias in the IR.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_IR_GLOBALALIAS_H
15#define LLVM_IR_GLOBALALIAS_H
16
17#include "llvm/ADT/ilist_node.h"
18#include "llvm/IR/GlobalIndirectSymbol.h"
19#include "llvm/IR/Value.h"
20
21namespace llvm {
22
23class Twine;
24class Module;
25template <typename ValueSubClass> class SymbolTableListTraits;
26
27class GlobalAlias : public GlobalIndirectSymbol,
28                    public ilist_node<GlobalAlias> {
29  friend class SymbolTableListTraits<GlobalAlias>;
30
31  GlobalAlias(Type *Ty, unsigned AddressSpace, LinkageTypes Linkage,
32              const Twine &Name, Constant *Aliasee, Module *Parent);
33
34public:
35  GlobalAlias(const GlobalAlias &) = delete;
36  GlobalAlias &operator=(const GlobalAlias &) = delete;
37
38  /// If a parent module is specified, the alias is automatically inserted into
39  /// the end of the specified module's alias list.
40  static GlobalAlias *create(Type *Ty, unsigned AddressSpace,
41                             LinkageTypes Linkage, const Twine &Name,
42                             Constant *Aliasee, Module *Parent);
43
44  // Without the Aliasee.
45  static GlobalAlias *create(Type *Ty, unsigned AddressSpace,
46                             LinkageTypes Linkage, const Twine &Name,
47                             Module *Parent);
48
49  // The module is taken from the Aliasee.
50  static GlobalAlias *create(Type *Ty, unsigned AddressSpace,
51                             LinkageTypes Linkage, const Twine &Name,
52                             GlobalValue *Aliasee);
53
54  // Type, Parent and AddressSpace taken from the Aliasee.
55  static GlobalAlias *create(LinkageTypes Linkage, const Twine &Name,
56                             GlobalValue *Aliasee);
57
58  // Linkage, Type, Parent and AddressSpace taken from the Aliasee.
59  static GlobalAlias *create(const Twine &Name, GlobalValue *Aliasee);
60
61  /// removeFromParent - This method unlinks 'this' from the containing module,
62  /// but does not delete it.
63  ///
64  void removeFromParent();
65
66  /// eraseFromParent - This method unlinks 'this' from the containing module
67  /// and deletes it.
68  ///
69  void eraseFromParent();
70
71  /// These methods retrieve and set alias target.
72  void setAliasee(Constant *Aliasee);
73  const Constant *getAliasee() const {
74    return getIndirectSymbol();
75  }
76  Constant *getAliasee() {
77    return getIndirectSymbol();
78  }
79
80  static bool isValidLinkage(LinkageTypes L) {
81    return isExternalLinkage(L) || isLocalLinkage(L) ||
82      isWeakLinkage(L) || isLinkOnceLinkage(L);
83  }
84
85  // Methods for support type inquiry through isa, cast, and dyn_cast:
86  static bool classof(const Value *V) {
87    return V->getValueID() == Value::GlobalAliasVal;
88  }
89};
90
91} // end namespace llvm
92
93#endif // LLVM_IR_GLOBALALIAS_H
94