GlobalAlias.h revision 0b8c9a80f20772c3793201ab5b251d3520b9cea3 
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/ADT/Twine.h"
19#include "llvm/ADT/ilist_node.h"
20#include "llvm/IR/GlobalValue.h"
21#include "llvm/IR/OperandTraits.h"
22
23namespace llvm {
24
25class Module;
26template<typename ValueSubClass, typename ItemParentClass>
27  class SymbolTableListTraits;
28
29class GlobalAlias : public GlobalValue, public ilist_node<GlobalAlias> {
30  friend class SymbolTableListTraits<GlobalAlias, Module>;
31  void operator=(const GlobalAlias &) LLVM_DELETED_FUNCTION;
32  GlobalAlias(const GlobalAlias &) LLVM_DELETED_FUNCTION;
33
34  void setParent(Module *parent);
35
36public:
37  // allocate space for exactly one operand
38  void *operator new(size_t s) {
39    return User::operator new(s, 1);
40  }
41  /// GlobalAlias ctor - If a parent module is specified, the alias is
42  /// automatically inserted into the end of the specified module's alias list.
43  GlobalAlias(Type *Ty, LinkageTypes Linkage, const Twine &Name = "",
44              Constant* Aliasee = 0, Module *Parent = 0);
45
46  /// Provide fast operand accessors
47  DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Constant);
48
49  /// removeFromParent - This method unlinks 'this' from the containing module,
50  /// but does not delete it.
51  ///
52  virtual void removeFromParent();
53
54  /// eraseFromParent - This method unlinks 'this' from the containing module
55  /// and deletes it.
56  ///
57  virtual void eraseFromParent();
58
59  /// set/getAliasee - These methods retrive and set alias target.
60  void setAliasee(Constant *GV);
61  const Constant *getAliasee() const {
62    return getOperand(0);
63  }
64  Constant *getAliasee() {
65    return getOperand(0);
66  }
67  /// getAliasedGlobal() - Aliasee can be either global or bitcast of
68  /// global. This method retrives the global for both aliasee flavours.
69  const GlobalValue *getAliasedGlobal() const;
70
71  /// resolveAliasedGlobal() - This method tries to ultimately resolve the alias
72  /// by going through the aliasing chain and trying to find the very last
73  /// global. Returns NULL if a cycle was found. If stopOnWeak is false, then
74  /// the whole chain aliasing chain is traversed, otherwise - only strong
75  /// aliases.
76  const GlobalValue *resolveAliasedGlobal(bool stopOnWeak = true) const;
77
78  // Methods for support type inquiry through isa, cast, and dyn_cast:
79  static inline bool classof(const Value *V) {
80    return V->getValueID() == Value::GlobalAliasVal;
81  }
82};
83
84template <>
85struct OperandTraits<GlobalAlias> :
86  public FixedNumOperandTraits<GlobalAlias, 1> {
87};
88
89DEFINE_TRANSPARENT_OPERAND_ACCESSORS(GlobalAlias, Constant)
90
91} // End llvm namespace
92
93#endif
94