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;
38 /// OperandList - This is a pointer to the array of Uses for this User.
39 /// For nodes of fixed arity (e.g. a binary operator) this array will live
40 /// prefixed to some derived class instance. For nodes of resizable variable
41 /// arity (e.g. PHINodes, SwitchInst etc.), this memory will be dynamically
42 /// allocated and should be destroyed by the classes' virtual dtor.
45 /// NumOperands - The number of values used by this User.
49 void *operator new(size_t s, unsigned Us);
50 User(const Type *ty, unsigned vty, Use *OpList, unsigned NumOps)
51 : Value(ty, vty), OperandList(OpList), NumOperands(NumOps) {}
52 Use *allocHungoffUses(unsigned) const;
53 void dropHungoffUses() {
54 Use::zap(OperandList, OperandList + NumOperands, true);
56 // Reset NumOperands so User::operator delete() does the right thing.
61 Use::zap(OperandList, OperandList + NumOperands);
63 /// operator delete - free memory allocated for User and Use objects
64 void operator delete(void *Usr);
65 /// placement delete - required by std, but never called.
66 void operator delete(void*, unsigned) {
67 assert(0 && "Constructor throws?");
69 /// placement delete - required by std, but never called.
70 void operator delete(void*, unsigned, bool) {
71 assert(0 && "Constructor throws?");
74 template <int Idx, typename U> static Use &OpFrom(const U *that) {
76 ? OperandTraits<U>::op_end(const_cast<U*>(that))[Idx]
77 : OperandTraits<U>::op_begin(const_cast<U*>(that))[Idx];
79 template <int Idx> Use &Op() {
80 return OpFrom<Idx>(this);
82 template <int Idx> const Use &Op() const {
83 return OpFrom<Idx>(this);
86 Value *getOperand(unsigned i) const {
87 assert(i < NumOperands && "getOperand() out of range!");
88 return OperandList[i];
90 void setOperand(unsigned i, Value *Val) {
91 assert(i < NumOperands && "setOperand() out of range!");
92 assert((!isa<Constant>((const Value*)this) ||
93 isa<GlobalValue>((const Value*)this)) &&
94 "Cannot mutate a constant with setOperand!");
97 const Use &getOperandUse(unsigned i) const {
98 assert(i < NumOperands && "getOperandUse() out of range!");
99 return OperandList[i];
101 Use &getOperandUse(unsigned i) {
102 assert(i < NumOperands && "getOperandUse() out of range!");
103 return OperandList[i];
106 unsigned getNumOperands() const { return NumOperands; }
108 // ---------------------------------------------------------------------------
109 // Operand Iterator interface...
111 typedef Use* op_iterator;
112 typedef const Use* const_op_iterator;
114 inline op_iterator op_begin() { return OperandList; }
115 inline const_op_iterator op_begin() const { return OperandList; }
116 inline op_iterator op_end() { return OperandList+NumOperands; }
117 inline const_op_iterator op_end() const { return OperandList+NumOperands; }
119 // dropAllReferences() - This function is in charge of "letting go" of all
120 // objects that this User refers to. This allows one to
121 // 'delete' a whole class at a time, even though there may be circular
122 // references... First all references are dropped, and all use counts go to
123 // zero. Then everything is deleted for real. Note that no operations are
124 // valid on an object that has "dropped all references", except operator
127 void dropAllReferences() {
128 for (op_iterator i = op_begin(), e = op_end(); i != e; ++i)
132 /// replaceUsesOfWith - Replaces all references to the "From" definition with
133 /// references to the "To" definition.
135 void replaceUsesOfWith(Value *From, Value *To);
137 // Methods for support type inquiry through isa, cast, and dyn_cast:
138 static inline bool classof(const User *) { return true; }
139 static inline bool classof(const Value *V) {
140 return isa<Instruction>(V) || isa<Constant>(V);
144 template<> struct simplify_type<User::op_iterator> {
145 typedef Value* SimpleType;
147 static SimpleType getSimplifiedValue(const User::op_iterator &Val) {
148 return static_cast<SimpleType>(Val->get());
152 template<> struct simplify_type<const User::op_iterator>
153 : public simplify_type<User::op_iterator> {};
155 template<> struct simplify_type<User::const_op_iterator> {
156 typedef Value* SimpleType;
158 static SimpleType getSimplifiedValue(const User::const_op_iterator &Val) {
159 return static_cast<SimpleType>(Val->get());
163 template<> struct simplify_type<const User::const_op_iterator>
164 : public simplify_type<User::const_op_iterator> {};
167 // value_use_iterator::getOperandNo - Requires the definition of the User class.
168 template<typename UserTy>
169 unsigned value_use_iterator<UserTy>::getOperandNo() const {
170 return U - U->getUser()->op_begin();
173 } // End llvm namespace