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.
48 Use *LegacyOperandList;
51 void *operator new(size_t s, unsigned Us);
53 User(Type *ty, unsigned vty, Use *OpList, unsigned NumOps)
55 setOperandList(OpList);
59 /// \brief Allocate the array of Uses, followed by a pointer
60 /// (with bottom bit set) to the User.
61 /// \param IsPhi identifies callers which are phi nodes and which need
62 /// N BasicBlock* allocated along with N
63 void allocHungoffUses(unsigned N, bool IsPhi = false);
65 /// \brief Grow the number of hung off uses. Note that allocHungoffUses
66 /// should be called if there are no uses.
67 void growHungoffUses(unsigned N, bool IsPhi = false);
71 // drop the hung off uses.
72 Use::zap(getOperandList(), getOperandList() + NumOperands, HasHungOffUses);
74 setOperandList(nullptr);
75 // Reset NumOperands so User::operator delete() does the right thing.
79 /// \brief Free memory allocated for User and Use objects.
80 void operator delete(void *Usr);
81 /// \brief Placement delete - required by std, but never called.
82 void operator delete(void*, unsigned) {
83 llvm_unreachable("Constructor throws?");
85 /// \brief Placement delete - required by std, but never called.
86 void operator delete(void*, unsigned, bool) {
87 llvm_unreachable("Constructor throws?");
90 template <int Idx, typename U> static Use &OpFrom(const U *that) {
92 ? OperandTraits<U>::op_end(const_cast<U*>(that))[Idx]
93 : OperandTraits<U>::op_begin(const_cast<U*>(that))[Idx];
95 template <int Idx> Use &Op() {
96 return OpFrom<Idx>(this);
98 template <int Idx> const Use &Op() const {
99 return OpFrom<Idx>(this);
102 void setOperandList(Use *NewList) {
103 LegacyOperandList = NewList;
106 Use *getOperandList() const {
107 return LegacyOperandList;
109 Value *getOperand(unsigned i) const {
110 assert(i < NumOperands && "getOperand() out of range!");
111 return getOperandList()[i];
113 void setOperand(unsigned i, Value *Val) {
114 assert(i < NumOperands && "setOperand() out of range!");
115 assert((!isa<Constant>((const Value*)this) ||
116 isa<GlobalValue>((const Value*)this)) &&
117 "Cannot mutate a constant with setOperand!");
118 getOperandList()[i] = Val;
120 const Use &getOperandUse(unsigned i) const {
121 assert(i < NumOperands && "getOperandUse() out of range!");
122 return getOperandList()[i];
124 Use &getOperandUse(unsigned i) {
125 assert(i < NumOperands && "getOperandUse() out of range!");
126 return getOperandList()[i];
129 unsigned getNumOperands() const { return NumOperands; }
131 // ---------------------------------------------------------------------------
132 // Operand Iterator interface...
134 typedef Use* op_iterator;
135 typedef const Use* const_op_iterator;
136 typedef iterator_range<op_iterator> op_range;
137 typedef iterator_range<const_op_iterator> const_op_range;
139 inline op_iterator op_begin() { return getOperandList(); }
140 inline const_op_iterator op_begin() const { return getOperandList(); }
141 inline op_iterator op_end() {
142 return getOperandList() + NumOperands;
144 inline const_op_iterator op_end() const {
145 return getOperandList() + NumOperands;
147 inline op_range operands() {
148 return op_range(op_begin(), op_end());
150 inline const_op_range operands() const {
151 return const_op_range(op_begin(), op_end());
154 /// \brief Iterator for directly iterating over the operand Values.
155 struct value_op_iterator
156 : iterator_adaptor_base<value_op_iterator, op_iterator,
157 std::random_access_iterator_tag, Value *,
158 ptrdiff_t, Value *, Value *> {
159 explicit value_op_iterator(Use *U = nullptr) : iterator_adaptor_base(U) {}
161 Value *operator*() const { return *I; }
162 Value *operator->() const { return operator*(); }
165 inline value_op_iterator value_op_begin() {
166 return value_op_iterator(op_begin());
168 inline value_op_iterator value_op_end() {
169 return value_op_iterator(op_end());
171 inline iterator_range<value_op_iterator> operand_values() {
172 return iterator_range<value_op_iterator>(value_op_begin(), value_op_end());
175 /// \brief Drop all references to operands.
177 /// This function is in charge of "letting go" of all objects that this User
178 /// refers to. This allows one to 'delete' a whole class at a time, even
179 /// though there may be circular references... First all references are
180 /// dropped, and all use counts go to zero. Then everything is deleted for
181 /// real. Note that no operations are valid on an object that has "dropped
182 /// all references", except operator delete.
183 void dropAllReferences() {
184 for (Use &U : operands())
188 /// \brief Replace uses of one Value with another.
190 /// Replaces all references to the "From" definition with references to the
192 void replaceUsesOfWith(Value *From, Value *To);
194 // Methods for support type inquiry through isa, cast, and dyn_cast:
195 static inline bool classof(const Value *V) {
196 return isa<Instruction>(V) || isa<Constant>(V);
200 template<> struct simplify_type<User::op_iterator> {
201 typedef Value* SimpleType;
202 static SimpleType getSimplifiedValue(User::op_iterator &Val) {
206 template<> struct simplify_type<User::const_op_iterator> {
207 typedef /*const*/ Value* SimpleType;
208 static SimpleType getSimplifiedValue(User::const_op_iterator &Val) {
213 } // End llvm namespace