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 
21 namespace llvm {
22 
23 class Twine;
24 class Module;
25 template <typename ValueSubClass> class SymbolTableListTraits;
26 
27 class 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 
34 public:
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);
getAliasee()73   const Constant *getAliasee() const {
74     return getIndirectSymbol();
75   }
getAliasee()76   Constant *getAliasee() {
77     return getIndirectSymbol();
78   }
79 
isValidLinkage(LinkageTypes L)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:
classof(const Value * V)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