include/llvm/GlobalAlias.h

   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 #include "llvm/ADT/Twine.h"
  22
  23 namespace llvm {
  24
  25 class Module;
  26 class Constant;
  27 template<typename ValueSubClass, typename ItemParentClass>
  28   class SymbolTableListTraits;
  29
  30 class 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
  37 public:
  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 Twine &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   virtual void removeFromParent();
  59
  60   /// eraseFromParent - This method unlinks 'this' from the containing module
  61   /// and deletes it.
  62   ///
  63   virtual void eraseFromParent();
  64
  65   /// set/getAliasee - These methods retrive and set alias target.
  66   void setAliasee(Constant *GV);
  67   const Constant *getAliasee() const {
  68     return cast_or_null<Constant>(getOperand(0));
  69   }
  70   Constant *getAliasee() {
  71     return cast_or_null<Constant>(getOperand(0));
  72   }
  73   /// getAliasedGlobal() - Aliasee can be either global or bitcast of
  74   /// global. This method retrives the global for both aliasee flavours.
  75   const GlobalValue *getAliasedGlobal() const;
  76
  77   /// resolveAliasedGlobal() - This method tries to ultimately resolve the alias
  78   /// by going through the aliasing chain and trying to find the very last
  79   /// global. Returns NULL if a cycle was found. If stopOnWeak is false, then
  80   /// the whole chain aliasing chain is traversed, otherwise - only strong
  81   /// aliases.
  82   const GlobalValue *resolveAliasedGlobal(bool stopOnWeak = true) const;
  83
  84   // Methods for support type inquiry through isa, cast, and dyn_cast:
  85   static inline bool classof(const GlobalAlias *) { return true; }
  86   static inline bool classof(const Value *V) {
  87     return V->getValueID() == Value::GlobalAliasVal;
  88   }
  89 };
  90
  91 template <>
  92 struct OperandTraits<GlobalAlias> :
  93   public FixedNumOperandTraits<GlobalAlias, 1> {
  94 };
  95
  96 DEFINE_TRANSPARENT_OPERAND_ACCESSORS(GlobalAlias, Value)
  97
  98 } // End llvm namespace
  99
 100 #endif