1 //===-------- llvm/GlobalAlias.h - GlobalAlias class ------------*- C++ -*-===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file contains the declaration of the GlobalAlias class, which
11 // represents a single function or variable alias in the IR.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #ifndef LLVM_IR_GLOBALALIAS_H
16 #define LLVM_IR_GLOBALALIAS_H
17 
18 #include "llvm/ADT/ilist_node.h"
19 #include "llvm/IR/GlobalIndirectSymbol.h"
20 #include "llvm/IR/Value.h"
21 
22 namespace llvm {
23 
24 class Twine;
25 class Module;
26 template <typename ValueSubClass> class SymbolTableListTraits;
27 
28 class GlobalAlias : public GlobalIndirectSymbol,
29                     public ilist_node<GlobalAlias> {
30   friend class SymbolTableListTraits<GlobalAlias>;
31 
32   GlobalAlias(Type *Ty, unsigned AddressSpace, LinkageTypes Linkage,
33               const Twine &Name, Constant *Aliasee, Module *Parent);
34 
35 public:
36   GlobalAlias(const GlobalAlias &) = delete;
37   GlobalAlias &operator=(const GlobalAlias &) = delete;
38 
39   /// If a parent module is specified, the alias is automatically inserted into
40   /// the end of the specified module's alias list.
41   static GlobalAlias *create(Type *Ty, unsigned AddressSpace,
42                              LinkageTypes Linkage, const Twine &Name,
43                              Constant *Aliasee, Module *Parent);
44 
45   // Without the Aliasee.
46   static GlobalAlias *create(Type *Ty, unsigned AddressSpace,
47                              LinkageTypes Linkage, const Twine &Name,
48                              Module *Parent);
49 
50   // The module is taken from the Aliasee.
51   static GlobalAlias *create(Type *Ty, unsigned AddressSpace,
52                              LinkageTypes Linkage, const Twine &Name,
53                              GlobalValue *Aliasee);
54 
55   // Type, Parent and AddressSpace taken from the Aliasee.
56   static GlobalAlias *create(LinkageTypes Linkage, const Twine &Name,
57                              GlobalValue *Aliasee);
58 
59   // Linkage, Type, Parent and AddressSpace taken from the Aliasee.
60   static GlobalAlias *create(const Twine &Name, GlobalValue *Aliasee);
61 
copyAttributesFrom(const GlobalValue * Src)62   void copyAttributesFrom(const GlobalValue *Src) {
63     GlobalValue::copyAttributesFrom(Src);
64   }
65 
66   /// removeFromParent - This method unlinks 'this' from the containing module,
67   /// but does not delete it.
68   ///
69   void removeFromParent();
70 
71   /// eraseFromParent - This method unlinks 'this' from the containing module
72   /// and deletes it.
73   ///
74   void eraseFromParent();
75 
76   /// These methods retrieve and set alias target.
77   void setAliasee(Constant *Aliasee);
getAliasee()78   const Constant *getAliasee() const {
79     return getIndirectSymbol();
80   }
getAliasee()81   Constant *getAliasee() {
82     return getIndirectSymbol();
83   }
84 
isValidLinkage(LinkageTypes L)85   static bool isValidLinkage(LinkageTypes L) {
86     return isExternalLinkage(L) || isLocalLinkage(L) ||
87       isWeakLinkage(L) || isLinkOnceLinkage(L);
88   }
89 
90   // Methods for support type inquiry through isa, cast, and dyn_cast:
classof(const Value * V)91   static bool classof(const Value *V) {
92     return V->getValueID() == Value::GlobalAliasVal;
93   }
94 };
95 
96 } // end namespace llvm
97 
98 #endif // LLVM_IR_GLOBALALIAS_H
99