GlobalAlias.h revision fed90b6d097d50881afb45e4d79f430db66dd741 
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_GLOBAL_ALIAS_H
16#define LLVM_GLOBAL_ALIAS_H
17
18#include "llvm/GlobalValue.h"
19#include "llvm/OperandTraits.h"
20#include "llvm/ADT/ilist_node.h"
21
22namespace llvm {
23
24class Module;
25class Constant;
26class PointerType;
27template<typename ValueSubClass, typename ItemParentClass>
28  class SymbolTableListTraits;
29
30class GlobalAlias : public GlobalValue, public ilist_node<GlobalAlias> {
31  friend class SymbolTableListTraits<GlobalAlias, Module>;
32  void operator=(const GlobalAlias &);     // Do not implement
33  GlobalAlias(const GlobalAlias &);     // Do not implement
34
35  void setParent(Module *parent);
36
37public:
38  // allocate space for exactly one operand
39  void *operator new(size_t s) {
40    return User::operator new(s, 1);
41  }
42  /// GlobalAlias ctor - If a parent module is specified, the alias is
43  /// automatically inserted into the end of the specified module's alias list.
44  GlobalAlias(const Type *Ty, LinkageTypes Linkage, const std::string &Name = "",
45              Constant* Aliasee = 0, Module *Parent = 0);
46
47  /// Provide fast operand accessors
48  DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
49
50  /// isDeclaration - Is this global variable lacking an initializer?  If so,
51  /// the global variable is defined in some other translation unit, and is thus
52  /// only a declaration here.
53  virtual bool isDeclaration() const;
54
55  /// removeFromParent - This method unlinks 'this' from the containing module,
56  /// but does not delete it.
57  ///
58  void removeFromParent();
59
60  /// eraseFromParent - This method unlinks 'this' from the containing module
61  /// and deletes it.
62  ///
63  void eraseFromParent();
64
65  virtual void print(std::ostream &OS) const;
66  void print(std::ostream *OS) const { if (OS) print(*OS); }
67
68  /// set/getAliasee - These methods retrive and set alias target.
69  void setAliasee(Constant* GV);
70  const Constant* getAliasee() const {
71    return cast_or_null<Constant>(getOperand(0));
72  }
73  Constant* getAliasee() {
74    return cast_or_null<Constant>(getOperand(0));
75  }
76  /// getAliasedGlobal() - Aliasee can be either global or bitcast of
77  /// global. This method retrives the global for both aliasee flavours.
78  const GlobalValue* getAliasedGlobal() const;
79
80  /// resolveAliasedGlobal() - This method tries to ultimately resolve the alias
81  /// by going through the aliasing chain and trying to find the very last
82  /// global. Returns NULL if a cycle was found.
83  const GlobalValue* resolveAliasedGlobal() const;
84
85  // Methods for support type inquiry through isa, cast, and dyn_cast:
86  static inline bool classof(const GlobalAlias *) { return true; }
87  static inline bool classof(const Value *V) {
88    return V->getValueID() == Value::GlobalAliasVal;
89  }
90};
91
92template <>
93struct OperandTraits<GlobalAlias> : FixedNumOperandTraits<1> {
94};
95
96DEFINE_TRANSPARENT_OPERAND_ACCESSORS(GlobalAlias, Value)
97
98} // End llvm namespace
99
100#endif
101