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
32 class User : public Value {
33 User(const User &); // Do not implement
34 void *operator new(size_t); // Do not implement
36 friend struct HungoffOperandTraits;
37 virtual void anchor();
39 /// OperandList - This is a pointer to the array of Uses for this User.
40 /// For nodes of fixed arity (e.g. a binary operator) this array will live
41 /// prefixed to some derived class instance. For nodes of resizable variable
42 /// arity (e.g. PHINodes, SwitchInst etc.), this memory will be dynamically
43 /// allocated and should be destroyed by the classes' virtual dtor.
46 /// NumOperands - The number of values used by this User.
50 void *operator new(size_t s, unsigned Us);
51 User(Type *ty, unsigned vty, Use *OpList, unsigned NumOps)
52 : Value(ty, vty), OperandList(OpList), NumOperands(NumOps) {}
53 Use *allocHungoffUses(unsigned) const;
54 void dropHungoffUses() {
55 Use::zap(OperandList, OperandList + NumOperands, true);
57 // Reset NumOperands so User::operator delete() does the right thing.
62 Use::zap(OperandList, OperandList + NumOperands);
64 /// operator delete - free memory allocated for User and Use objects
65 void operator delete(void *Usr);
66 /// placement delete - required by std, but never called.
67 void operator delete(void*, unsigned) {
68 assert(0 && "Constructor throws?");
70 /// placement delete - required by std, but never called.
71 void operator delete(void*, unsigned, bool) {
72 assert(0 && "Constructor throws?");
75 template <int Idx, typename U> static Use &OpFrom(const U *that) {
77 ? OperandTraits<U>::op_end(const_cast<U*>(that))[Idx]
78 : OperandTraits<U>::op_begin(const_cast<U*>(that))[Idx];
80 template <int Idx> Use &Op() {
81 return OpFrom<Idx>(this);
83 template <int Idx> const Use &Op() const {
84 return OpFrom<Idx>(this);
87 Value *getOperand(unsigned i) const {
88 assert(i < NumOperands && "getOperand() out of range!");
89 return OperandList[i];
91 void setOperand(unsigned i, Value *Val) {
92 assert(i < NumOperands && "setOperand() out of range!");
93 assert((!isa<Constant>((const Value*)this) ||
94 isa<GlobalValue>((const Value*)this)) &&
95 "Cannot mutate a constant with setOperand!");
98 const Use &getOperandUse(unsigned i) const {
99 assert(i < NumOperands && "getOperandUse() out of range!");
100 return OperandList[i];
102 Use &getOperandUse(unsigned i) {
103 assert(i < NumOperands && "getOperandUse() out of range!");
104 return OperandList[i];
107 unsigned getNumOperands() const { return NumOperands; }
109 // ---------------------------------------------------------------------------
110 // Operand Iterator interface...
112 typedef Use* op_iterator;
113 typedef const Use* const_op_iterator;
115 inline op_iterator op_begin() { return OperandList; }
116 inline const_op_iterator op_begin() const { return OperandList; }
117 inline op_iterator op_end() { return OperandList+NumOperands; }
118 inline const_op_iterator op_end() const { return OperandList+NumOperands; }
120 // dropAllReferences() - This function is in charge of "letting go" of all
121 // objects that this User refers to. This allows one to
122 // 'delete' a whole class at a time, even though there may be circular
123 // references... First all references are dropped, and all use counts go to
124 // zero. Then everything is deleted for real. Note that no operations are
125 // valid on an object that has "dropped all references", except operator
128 void dropAllReferences() {
129 for (op_iterator i = op_begin(), e = op_end(); i != e; ++i)
133 /// replaceUsesOfWith - Replaces all references to the "From" definition with
134 /// references to the "To" definition.
136 void replaceUsesOfWith(Value *From, Value *To);
138 // Methods for support type inquiry through isa, cast, and dyn_cast:
139 static inline bool classof(const User *) { return true; }
140 static inline bool classof(const Value *V) {
141 return isa<Instruction>(V) || isa<Constant>(V);
145 template<> struct simplify_type<User::op_iterator> {
146 typedef Value* SimpleType;
148 static SimpleType getSimplifiedValue(const User::op_iterator &Val) {
149 return static_cast<SimpleType>(Val->get());
153 template<> struct simplify_type<const User::op_iterator>
154 : public simplify_type<User::op_iterator> {};
156 template<> struct simplify_type<User::const_op_iterator> {
157 typedef Value* SimpleType;
159 static SimpleType getSimplifiedValue(const User::const_op_iterator &Val) {
160 return static_cast<SimpleType>(Val->get());
164 template<> struct simplify_type<const User::const_op_iterator>
165 : public simplify_type<User::const_op_iterator> {};
168 // value_use_iterator::getOperandNo - Requires the definition of the User class.
169 template<typename UserTy>
170 unsigned value_use_iterator<UserTy>::getOperandNo() const {
171 return U - U->getUser()->op_begin();
174 } // End llvm namespace