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 new(size_t s)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); getAliasee()67 const Constant* getAliasee() const { 68 return cast_or_null<Constant>(getOperand(0)); 69 } getAliasee()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: classof(const GlobalAlias *)85 static inline bool classof(const GlobalAlias *) { return true; } classof(const Value * V)86 static inline bool classof(const Value *V) { 87 return V->getValueID() == Value::GlobalAliasVal; 88 } 89 }; 90 91 template <> 92 struct OperandTraits<GlobalAlias> : public FixedNumOperandTraits<1> { 93 }; 94 95 DEFINE_TRANSPARENT_OPERAND_ACCESSORS(GlobalAlias, Value) 96 97 } // End llvm namespace 98 99 #endif 100