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/GlobalValue.h"
19#include "llvm/IR/OperandTraits.h"
20#include "llvm/IR/Value.h"
21
22namespace llvm {
23
24class Twine;
25class Module;
26template <typename ValueSubClass, typename... Args> class SymbolTableListTraits;
27
28class GlobalAlias : public GlobalValue, 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 // allocate space for exactly one operand
62 void *operator new(size_t S) { return User::operator new(Size: S, Us: 1); }
63 void operator delete(void *Ptr) { User::operator delete(Usr: Ptr); }
64
65 /// Provide fast operand accessors
66 DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Constant);
67
68 void copyAttributesFrom(const GlobalAlias *Src) {
69 GlobalValue::copyAttributesFrom(Src);
70 }
71
72 /// removeFromParent - This method unlinks 'this' from the containing module,
73 /// but does not delete it.
74 ///
75 void removeFromParent();
76
77 /// eraseFromParent - This method unlinks 'this' from the containing module
78 /// and deletes it.
79 ///
80 void eraseFromParent();
81
82 /// These methods retrieve and set alias target.
83 void setAliasee(Constant *Aliasee);
84 const Constant *getAliasee() const {
85 return static_cast<Constant *>(Op<0>().get());
86 }
87 Constant *getAliasee() { return static_cast<Constant *>(Op<0>().get()); }
88
89 const GlobalObject *getAliaseeObject() const;
90 GlobalObject *getAliaseeObject() {
91 return const_cast<GlobalObject *>(
92 static_cast<const GlobalAlias *>(this)->getAliaseeObject());
93 }
94
95 static bool isValidLinkage(LinkageTypes L) {
96 return isExternalLinkage(Linkage: L) || isLocalLinkage(Linkage: L) || isWeakLinkage(Linkage: L) ||
97 isLinkOnceLinkage(Linkage: L) || isAvailableExternallyLinkage(Linkage: L);
98 }
99
100 // Methods for support type inquiry through isa, cast, and dyn_cast:
101 static bool classof(const Value *V) {
102 return V->getValueID() == Value::GlobalAliasVal;
103 }
104};
105
106template <>
107struct OperandTraits<GlobalAlias>
108 : public FixedNumOperandTraits<GlobalAlias, 1> {};
109
110DEFINE_TRANSPARENT_OPERAND_ACCESSORS(GlobalAlias, Constant)
111
112} // end namespace llvm
113
114#endif // LLVM_IR_GLOBALALIAS_H
115