LLVM API Documentation
00001 //===-- llvm/Use.h - Definition of the Use class ----------------*- C++ -*-===// 00002 // 00003 // The LLVM Compiler Infrastructure 00004 // 00005 // This file was developed by the LLVM research group and is distributed under 00006 // the University of Illinois Open Source License. See LICENSE.TXT for details. 00007 // 00008 //===----------------------------------------------------------------------===// 00009 // 00010 // This defines the Use class. The Use class represents the operand of an 00011 // instruction or some other User instance which refers to a Value. The Use 00012 // class keeps the "use list" of the referenced value up to date. 00013 // 00014 //===----------------------------------------------------------------------===// 00015 00016 #ifndef LLVM_USE_H 00017 #define LLVM_USE_H 00018 00019 #include "llvm/Support/Casting.h" 00020 #include "llvm/ADT/iterator" 00021 00022 namespace llvm { 00023 00024 class Value; 00025 class User; 00026 00027 00028 //===----------------------------------------------------------------------===// 00029 // Use Class 00030 //===----------------------------------------------------------------------===// 00031 00032 // Use is here to make keeping the "use" list of a Value up-to-date really easy. 00033 // 00034 class Use { 00035 public: 00036 inline void init(Value *V, User *U); 00037 00038 Use(Value *V, User *U) { init(V, U); } 00039 Use(const Use &U) { init(U.Val, U.U); } 00040 inline ~Use(); 00041 00042 /// Default ctor - This leaves the Use completely unitialized. The only thing 00043 /// that is valid to do with this use is to call the "init" method. 00044 inline Use() : Val(0) {} 00045 00046 00047 operator Value*() const { return Val; } 00048 Value *get() const { return Val; } 00049 User *getUser() const { return U; } 00050 00051 inline void set(Value *Val); 00052 00053 Value *operator=(Value *RHS) { 00054 set(RHS); 00055 return RHS; 00056 } 00057 const Use &operator=(const Use &RHS) { 00058 set(RHS.Val); 00059 return *this; 00060 } 00061 00062 Value *operator->() { return Val; } 00063 const Value *operator->() const { return Val; } 00064 00065 Use *getNext() const { return Next; } 00066 private: 00067 Use *Next, **Prev; 00068 Value *Val; 00069 User *U; 00070 00071 void addToList(Use **List) { 00072 Next = *List; 00073 if (Next) Next->Prev = &Next; 00074 Prev = List; 00075 *List = this; 00076 } 00077 void removeFromList() { 00078 *Prev = Next; 00079 if (Next) Next->Prev = Prev; 00080 } 00081 00082 friend class Value; 00083 }; 00084 00085 // simplify_type - Allow clients to treat uses just like values when using 00086 // casting operators. 00087 template<> struct simplify_type<Use> { 00088 typedef Value* SimpleType; 00089 static SimpleType getSimplifiedValue(const Use &Val) { 00090 return static_cast<SimpleType>(Val.get()); 00091 } 00092 }; 00093 template<> struct simplify_type<const Use> { 00094 typedef Value* SimpleType; 00095 static SimpleType getSimplifiedValue(const Use &Val) { 00096 return static_cast<SimpleType>(Val.get()); 00097 } 00098 }; 00099 00100 00101 00102 template<typename UserTy> // UserTy == 'User' or 'const User' 00103 class value_use_iterator : public forward_iterator<UserTy*, ptrdiff_t> { 00104 typedef forward_iterator<UserTy*, ptrdiff_t> super; 00105 typedef value_use_iterator<UserTy> _Self; 00106 00107 Use *U; 00108 value_use_iterator(Use *u) : U(u) {} 00109 friend class Value; 00110 public: 00111 typedef typename super::reference reference; 00112 typedef typename super::pointer pointer; 00113 00114 value_use_iterator(const _Self &I) : U(I.U) {} 00115 value_use_iterator() {} 00116 00117 bool operator==(const _Self &x) const { 00118 return U == x.U; 00119 } 00120 bool operator!=(const _Self &x) const { 00121 return !operator==(x); 00122 } 00123 00124 // Iterator traversal: forward iteration only 00125 _Self &operator++() { // Preincrement 00126 assert(U && "Cannot increment end iterator!"); 00127 U = U->getNext(); 00128 return *this; 00129 } 00130 _Self operator++(int) { // Postincrement 00131 _Self tmp = *this; ++*this; return tmp; 00132 } 00133 00134 // Retrieve a reference to the current SCC 00135 UserTy *operator*() const { 00136 assert(U && "Cannot increment end iterator!"); 00137 return U->getUser(); 00138 } 00139 00140 UserTy *operator->() const { return operator*(); } 00141 00142 Use &getUse() const { return *U; } 00143 }; 00144 00145 00146 template<> struct simplify_type<value_use_iterator<User> > { 00147 typedef User* SimpleType; 00148 00149 static SimpleType getSimplifiedValue(const value_use_iterator<User> &Val) { 00150 return *Val; 00151 } 00152 }; 00153 00154 template<> struct simplify_type<const value_use_iterator<User> > 00155 : public simplify_type<value_use_iterator<User> > {}; 00156 00157 template<> struct simplify_type<value_use_iterator<const User> > { 00158 typedef const User* SimpleType; 00159 00160 static SimpleType getSimplifiedValue(const 00161 value_use_iterator<const User> &Val) { 00162 return *Val; 00163 } 00164 }; 00165 00166 template<> struct simplify_type<const value_use_iterator<const User> > 00167 : public simplify_type<value_use_iterator<const User> > {}; 00168 00169 } // End llvm namespace 00170 00171 #endif