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*);
42 class User : public Value {
43 User(const User &); // Do not implement
44 void *operator new(size_t); // Do not implement
46 friend struct HungoffOperandTraits;
48 /// OperandList - This is a pointer to the array of Uses for this User.
49 /// For nodes of fixed arity (e.g. a binary operator) this array will live
50 /// prefixed to some derived class instance. For nodes of resizable variable
51 /// arity (e.g. PHINodes, SwitchInst etc.), this memory will be dynamically
52 /// allocated and should be destroyed by the classes' virtual dtor.
55 /// NumOperands - The number of values used by this User.
59 void *operator new(size_t s, unsigned Us);
60 User(const Type *ty, unsigned vty, Use *OpList, unsigned NumOps)
61 : Value(ty, vty), OperandList(OpList), NumOperands(NumOps) {}
62 Use *allocHungoffUses(unsigned) const;
63 void dropHungoffUses(Use *U) {
64 if (OperandList == U) {
68 Use::zap(U, U->getImpliedUser(), true);
72 Use::zap(OperandList, OperandList + NumOperands);
74 /// operator delete - free memory allocated for User and Use objects
75 void operator delete(void *Usr);
76 /// placement delete - required by std, but never called.
77 void operator delete(void*, unsigned) {
78 assert(0 && "Constructor throws?");
80 /// placement delete - required by std, but never called.
81 void operator delete(void*, unsigned, bool) {
82 assert(0 && "Constructor throws?");
85 template <int Idx, typename U> static Use &OpFrom(const U *that) {
87 ? OperandTraits<U>::op_end(const_cast<U*>(that))[Idx]
88 : OperandTraits<U>::op_begin(const_cast<U*>(that))[Idx];
90 template <int Idx> Use &Op() {
91 return OpFrom<Idx>(this);
93 template <int Idx> const Use &Op() const {
94 return OpFrom<Idx>(this);
97 Value *getOperand(unsigned i) const {
98 assert(i < NumOperands && "getOperand() out of range!");
99 return OperandList[i];
101 void setOperand(unsigned i, Value *Val) {
102 assert(i < NumOperands && "setOperand() out of range!");
103 assert((!isa<Constant>((const Value*)this) ||
104 isa<GlobalValue>((const Value*)this)) &&
105 "Cannot mutate a constant with setOperand!");
106 OperandList[i] = Val;
108 const Use &getOperandUse(unsigned i) const {
109 assert(i < NumOperands && "getOperand() out of range!");
110 return OperandList[i];
112 Use &getOperandUse(unsigned i) {
113 assert(i < NumOperands && "getOperand() out of range!");
114 return OperandList[i];
117 unsigned getNumOperands() const { return NumOperands; }
119 // ---------------------------------------------------------------------------
120 // Operand Iterator interface...
122 typedef Use* op_iterator;
123 typedef const Use* const_op_iterator;
125 inline op_iterator op_begin() { return OperandList; }
126 inline const_op_iterator op_begin() const { return OperandList; }
127 inline op_iterator op_end() { return OperandList+NumOperands; }
128 inline const_op_iterator op_end() const { return OperandList+NumOperands; }
130 // dropAllReferences() - This function is in charge of "letting go" of all
131 // objects that this User refers to. This allows one to
132 // 'delete' a whole class at a time, even though there may be circular
133 // references... First all references are dropped, and all use counts go to
134 // zero. Then everything is deleted for real. Note that no operations are
135 // valid on an object that has "dropped all references", except operator
138 void dropAllReferences() {
139 for (op_iterator i = op_begin(), e = op_end(); i != e; ++i)
143 /// replaceUsesOfWith - Replaces all references to the "From" definition with
144 /// references to the "To" definition.
146 void replaceUsesOfWith(Value *From, Value *To);
148 // Methods for support type inquiry through isa, cast, and dyn_cast:
149 static inline bool classof(const User *) { return true; }
150 static inline bool classof(const Value *V) {
151 return isa<Instruction>(V) || isa<Constant>(V);
155 inline Use *OperandTraits<User>::op_begin(User *U) {
156 return U->op_begin();
159 inline Use *OperandTraits<User>::op_end(User *U) {
163 inline unsigned OperandTraits<User>::operands(const User *U) {
164 return U->getNumOperands();
167 template<> struct simplify_type<User::op_iterator> {
168 typedef Value* SimpleType;
170 static SimpleType getSimplifiedValue(const User::op_iterator &Val) {
171 return static_cast<SimpleType>(Val->get());
175 template<> struct simplify_type<const User::op_iterator>
176 : public simplify_type<User::op_iterator> {};
178 template<> struct simplify_type<User::const_op_iterator> {
179 typedef Value* SimpleType;
181 static SimpleType getSimplifiedValue(const User::const_op_iterator &Val) {
182 return static_cast<SimpleType>(Val->get());
186 template<> struct simplify_type<const User::const_op_iterator>
187 : public simplify_type<User::const_op_iterator> {};
190 // value_use_iterator::getOperandNo - Requires the definition of the User class.
191 template<typename UserTy>
192 unsigned value_use_iterator<UserTy>::getOperandNo() const {
193 return U - U->getUser()->op_begin();
196 } // End llvm namespace