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 uses 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 Users.
15 // * Constants may be users of other constants (think arrays and stuff)
17 //===----------------------------------------------------------------------===//
22 #include "llvm/Support/ErrorHandling.h"
23 #include "llvm/Value.h"
27 /// OperandTraits - Compile-time customization of
28 /// operand-related allocators and accessors
29 /// for use of the User class
33 class User : public Value {
34 User(const User &); // Do not implement
35 void *operator new(size_t); // Do not implement
37 friend struct HungoffOperandTraits;
38 virtual void anchor();
40 /// OperandList - This is a pointer to the array of Uses for this User.
41 /// For nodes of fixed arity (e.g. a binary operator) this array will live
42 /// prefixed to some derived class instance. For nodes of resizable variable
43 /// arity (e.g. PHINodes, SwitchInst etc.), this memory will be dynamically
44 /// allocated and should be destroyed by the classes' virtual dtor.
47 /// NumOperands - The number of values used by this User.
51 void *operator new(size_t s, unsigned Us);
52 User(Type *ty, unsigned vty, Use *OpList, unsigned NumOps)
53 : Value(ty, vty), OperandList(OpList), NumOperands(NumOps) {}
54 Use *allocHungoffUses(unsigned) const;
55 void dropHungoffUses() {
56 Use::zap(OperandList, OperandList + NumOperands, true);
58 // Reset NumOperands so User::operator delete() does the right thing.
63 Use::zap(OperandList, OperandList + NumOperands);
65 /// operator delete - free memory allocated for User and Use objects
66 void operator delete(void *Usr);
67 /// placement delete - required by std, but never called.
68 void operator delete(void*, unsigned) {
69 llvm_unreachable("Constructor throws?");
71 /// placement delete - required by std, but never called.
72 void operator delete(void*, unsigned, bool) {
73 llvm_unreachable("Constructor throws?");
76 template <int Idx, typename U> static Use &OpFrom(const U *that) {
78 ? OperandTraits<U>::op_end(const_cast<U*>(that))[Idx]
79 : OperandTraits<U>::op_begin(const_cast<U*>(that))[Idx];
81 template <int Idx> Use &Op() {
82 return OpFrom<Idx>(this);
84 template <int Idx> const Use &Op() const {
85 return OpFrom<Idx>(this);
88 Value *getOperand(unsigned i) const {
89 assert(i < NumOperands && "getOperand() out of range!");
90 return OperandList[i];
92 void setOperand(unsigned i, Value *Val) {
93 assert(i < NumOperands && "setOperand() out of range!");
94 assert((!isa<Constant>((const Value*)this) ||
95 isa<GlobalValue>((const Value*)this)) &&
96 "Cannot mutate a constant with setOperand!");
99 const Use &getOperandUse(unsigned i) const {
100 assert(i < NumOperands && "getOperandUse() out of range!");
101 return OperandList[i];
103 Use &getOperandUse(unsigned i) {
104 assert(i < NumOperands && "getOperandUse() out of range!");
105 return OperandList[i];
108 unsigned getNumOperands() const { return NumOperands; }
110 // ---------------------------------------------------------------------------
111 // Operand Iterator interface...
113 typedef Use* op_iterator;
114 typedef const Use* const_op_iterator;
116 inline op_iterator op_begin() { return OperandList; }
117 inline const_op_iterator op_begin() const { return OperandList; }
118 inline op_iterator op_end() { return OperandList+NumOperands; }
119 inline const_op_iterator op_end() const { return OperandList+NumOperands; }
121 // dropAllReferences() - This function is in charge of "letting go" of all
122 // objects that this User refers to. This allows one to
123 // 'delete' a whole class at a time, even though there may be circular
124 // references... First all references are dropped, and all use counts go to
125 // zero. Then everything is deleted for real. Note that no operations are
126 // valid on an object that has "dropped all references", except operator
129 void dropAllReferences() {
130 for (op_iterator i = op_begin(), e = op_end(); i != e; ++i)
134 /// replaceUsesOfWith - Replaces all references to the "From" definition with
135 /// references to the "To" definition.
137 void replaceUsesOfWith(Value *From, Value *To);
139 // Methods for support type inquiry through isa, cast, and dyn_cast:
140 static inline bool classof(const User *) { return true; }
141 static inline bool classof(const Value *V) {
142 return isa<Instruction>(V) || isa<Constant>(V);
146 template<> struct simplify_type<User::op_iterator> {
147 typedef Value* SimpleType;
149 static SimpleType getSimplifiedValue(const User::op_iterator &Val) {
150 return static_cast<SimpleType>(Val->get());
154 template<> struct simplify_type<const User::op_iterator>
155 : public simplify_type<User::op_iterator> {};
157 template<> struct simplify_type<User::const_op_iterator> {
158 typedef Value* SimpleType;
160 static SimpleType getSimplifiedValue(const User::const_op_iterator &Val) {
161 return static_cast<SimpleType>(Val->get());
165 template<> struct simplify_type<const User::const_op_iterator>
166 : public simplify_type<User::const_op_iterator> {};
169 // value_use_iterator::getOperandNo - Requires the definition of the User class.
170 template<typename UserTy>
171 unsigned value_use_iterator<UserTy>::getOperandNo() const {
172 return U - U->getUser()->op_begin();
175 } // End llvm namespace