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 //===----------------------------------------------------------------------===//
19 #ifndef LLVM_IR_USER_H
20 #define LLVM_IR_USER_H
22 #include "llvm/ADT/iterator.h"
23 #include "llvm/ADT/iterator_range.h"
24 #include "llvm/IR/Value.h"
25 #include "llvm/Support/ErrorHandling.h"
29 /// \brief Compile-time customization of User operands.
31 /// Customizes operand-related allocators and accessors.
35 class User : public Value {
36 User(const User &) = delete;
37 void *operator new(size_t) = delete;
39 friend struct HungoffOperandTraits;
40 virtual void anchor();
42 /// \brief This is a pointer to the array of Uses for this User.
44 /// For nodes of fixed arity (e.g. a binary operator) this array will live
45 /// prefixed to some derived class instance. For nodes of resizable variable
46 /// arity (e.g. PHINodes, SwitchInst etc.), this memory will be dynamically
47 /// allocated and should be destroyed by the classes' virtual dtor.
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) {
55 Use *allocHungoffUses(unsigned) const;
56 void dropHungoffUses() {
57 Use::zap(OperandList, OperandList + NumOperands, true);
58 OperandList = nullptr;
59 // Reset NumOperands so User::operator delete() does the right thing.
63 ~User() override { Use::zap(OperandList, OperandList + NumOperands); }
64 /// \brief Free memory allocated for User and Use objects.
65 void operator delete(void *Usr);
66 /// \brief Placement delete - required by std, but never called.
67 void operator delete(void*, unsigned) {
68 llvm_unreachable("Constructor throws?");
70 /// \brief Placement delete - required by std, but never called.
71 void operator delete(void*, unsigned, bool) {
72 llvm_unreachable("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;
114 typedef iterator_range<op_iterator> op_range;
115 typedef iterator_range<const_op_iterator> const_op_range;
117 inline op_iterator op_begin() { return OperandList; }
118 inline const_op_iterator op_begin() const { return OperandList; }
119 inline op_iterator op_end() { return OperandList+NumOperands; }
120 inline const_op_iterator op_end() const { return OperandList+NumOperands; }
121 inline op_range operands() {
122 return op_range(op_begin(), op_end());
124 inline const_op_range operands() const {
125 return const_op_range(op_begin(), op_end());
128 /// \brief Iterator for directly iterating over the operand Values.
129 struct value_op_iterator
130 : iterator_adaptor_base<value_op_iterator, op_iterator,
131 std::random_access_iterator_tag, Value *,
132 ptrdiff_t, Value *, Value *> {
133 explicit value_op_iterator(Use *U = nullptr) : iterator_adaptor_base(U) {}
135 Value *operator*() const { return *I; }
136 Value *operator->() const { return operator*(); }
139 inline value_op_iterator value_op_begin() {
140 return value_op_iterator(op_begin());
142 inline value_op_iterator value_op_end() {
143 return value_op_iterator(op_end());
145 inline iterator_range<value_op_iterator> operand_values() {
146 return iterator_range<value_op_iterator>(value_op_begin(), value_op_end());
149 /// \brief Drop all references to operands.
151 /// This function is in charge of "letting go" of all objects that this User
152 /// refers to. This allows one to 'delete' a whole class at a time, even
153 /// though there may be circular references... First all references are
154 /// dropped, and all use counts go to zero. Then everything is deleted for
155 /// real. Note that no operations are valid on an object that has "dropped
156 /// all references", except operator delete.
157 void dropAllReferences() {
158 for (Use &U : operands())
162 /// \brief Replace uses of one Value with another.
164 /// Replaces all references to the "From" definition with references to the
166 void replaceUsesOfWith(Value *From, Value *To);
168 // Methods for support type inquiry through isa, cast, and dyn_cast:
169 static inline bool classof(const Value *V) {
170 return isa<Instruction>(V) || isa<Constant>(V);
174 template<> struct simplify_type<User::op_iterator> {
175 typedef Value* SimpleType;
176 static SimpleType getSimplifiedValue(User::op_iterator &Val) {
180 template<> struct simplify_type<User::const_op_iterator> {
181 typedef /*const*/ Value* SimpleType;
182 static SimpleType getSimplifiedValue(User::const_op_iterator &Val) {
187 } // End llvm namespace