1 //===-- llvm/User.h - User class definition ---------------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This class defines the interface that one who 'use's a Value must implement.
11 // Each instance of the Value class keeps track of what User's have handles
14 // * Instructions are the largest class of User's.
15 // * Constants may be users of other constants (think arrays and stuff)
17 //===----------------------------------------------------------------------===//
22 #include "llvm/Value.h"
26 /// OperandTraits - Compile-time customization of
27 /// operand-related allocators and accessors
28 /// for use of the User class
34 /// OperandTraits<User> - specialization to User
36 struct OperandTraits<User> {
37 static inline Use *op_begin(User*);
38 static inline Use *op_end(User*);
39 static inline unsigned operands(const User*);
44 static inline void *allocate(unsigned);
47 class User : public Value {
48 User(const User &); // Do not implement
49 void *operator new(size_t); // Do not implement
51 friend struct HungoffOperandTraits;
53 /// OperandList - This is a pointer to the array of Users for this operand.
54 /// For nodes of fixed arity (e.g. a binary operator) this array will live
55 /// prefixed to the derived class. For nodes of resizable variable arity
56 /// (e.g. PHINodes, SwitchInst etc.), this memory will be dynamically
57 /// allocated and should be destroyed by the classes'
61 /// NumOperands - The number of values used by this User.
65 void *operator new(size_t s, unsigned Us);
66 User(const Type *ty, unsigned vty, Use *OpList, unsigned NumOps)
67 : Value(ty, vty), OperandList(OpList), NumOperands(NumOps) {}
68 Use *allocHungoffUses(unsigned) const;
69 void dropHungoffUses(Use *U) {
70 if (OperandList == U) {
74 Use::zap(U, U->getImpliedUser(), true);
78 Use::zap(OperandList, OperandList + NumOperands);
80 /// operator delete - free memory allocated for User and Use objects
81 void operator delete(void *Usr);
82 /// placement delete - required by std, but never called.
83 void operator delete(void*, unsigned) {
84 assert(0 && "Constructor throws?");
86 template <unsigned Idx> Use &Op() {
87 return OperandTraits<User>::op_begin(this)[Idx];
89 template <unsigned Idx> const Use &Op() const {
90 return OperandTraits<User>::op_begin(const_cast<User*>(this))[Idx];
92 Value *getOperand(unsigned i) const {
93 assert(i < NumOperands && "getOperand() out of range!");
94 return OperandList[i];
96 void setOperand(unsigned i, Value *Val) {
97 assert(i < NumOperands && "setOperand() out of range!");
98 assert((!isa<Constant>((const Value*)this) ||
99 isa<GlobalValue>((const Value*)this)) &&
100 "Cannot mutate a constant with setOperand!");
101 OperandList[i] = Val;
103 unsigned getNumOperands() const { return NumOperands; }
105 // ---------------------------------------------------------------------------
106 // Operand Iterator interface...
108 typedef Use* op_iterator;
109 typedef const Use* const_op_iterator;
111 inline op_iterator op_begin() { return OperandList; }
112 inline const_op_iterator op_begin() const { return OperandList; }
113 inline op_iterator op_end() { return OperandList+NumOperands; }
114 inline const_op_iterator op_end() const { return OperandList+NumOperands; }
116 // dropAllReferences() - This function is in charge of "letting go" of all
117 // objects that this User refers to. This allows one to
118 // 'delete' a whole class at a time, even though there may be circular
119 // references... First all references are dropped, and all use counts go to
120 // zero. Then everything is deleted for real. Note that no operations are
121 // valid on an object that has "dropped all references", except operator
124 void dropAllReferences() {
125 for (op_iterator i = op_begin(), e = op_end(); i != e; ++i)
129 /// replaceUsesOfWith - Replaces all references to the "From" definition with
130 /// references to the "To" definition.
132 void replaceUsesOfWith(Value *From, Value *To);
134 // Methods for support type inquiry through isa, cast, and dyn_cast:
135 static inline bool classof(const User *) { return true; }
136 static inline bool classof(const Value *V) {
137 return isa<Instruction>(V) || isa<Constant>(V);
141 inline Use *OperandTraits<User>::op_begin(User *U) {
142 return U->op_begin();
145 inline Use *OperandTraits<User>::op_end(User *U) {
149 inline unsigned OperandTraits<User>::operands(const User *U) {
150 return U->getNumOperands();
153 template<> struct simplify_type<User::op_iterator> {
154 typedef Value* SimpleType;
156 static SimpleType getSimplifiedValue(const User::op_iterator &Val) {
157 return static_cast<SimpleType>(Val->get());
161 template<> struct simplify_type<const User::op_iterator>
162 : public simplify_type<User::op_iterator> {};
164 template<> struct simplify_type<User::const_op_iterator> {
165 typedef Value* SimpleType;
167 static SimpleType getSimplifiedValue(const User::const_op_iterator &Val) {
168 return static_cast<SimpleType>(Val->get());
172 template<> struct simplify_type<const User::const_op_iterator>
173 : public simplify_type<User::const_op_iterator> {};
176 // value_use_iterator::getOperandNo - Requires the definition of the User class.
177 template<typename UserTy>
178 unsigned value_use_iterator<UserTy>::getOperandNo() const {
179 return U - U->getUser()->op_begin();
182 } // End llvm namespace