1 //===-- llvm/Value.h - Definition of the Value class ------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines the very important Value class. This is subclassed by a
11 // bunch of other important classes, like Instruction, Function, Type, etc...
13 // This file also defines the Use<> template for users of value.
15 //===----------------------------------------------------------------------===//
20 #include "llvm/AbstractTypeUser.h"
22 #include "llvm/Support/Casting.h"
36 //===----------------------------------------------------------------------===//
38 //===----------------------------------------------------------------------===//
40 /// Value - The base class of all values computed by a program that may be used
41 /// as operands to other values.
45 unsigned SubclassID; // Subclass identifier (for isa/dyn_cast)
50 void operator=(const Value &); // Do not implement
51 Value(const Value &); // Do not implement
54 Value(const Type *Ty, unsigned scid, const std::string &name = "");
57 /// dump - Support for debugging, callable in GDB: V->dump()
59 virtual void dump() const;
61 /// print - Implement operator<< on Value...
63 virtual void print(std::ostream &O) const = 0;
65 /// All values are typed, get the type of this value.
67 inline const Type *getType() const { return Ty; }
69 // All values can potentially be named...
70 inline bool hasName() const { return !Name.empty(); }
71 inline const std::string &getName() const { return Name; }
73 virtual void setName(const std::string &name, SymbolTable * = 0) {
77 /// replaceAllUsesWith - Go through the uses list for this definition and make
78 /// each use point to "V" instead of "this". After this completes, 'this's
79 /// use list is guaranteed to be empty.
81 void replaceAllUsesWith(Value *V);
83 // uncheckedReplaceAllUsesWith - Just like replaceAllUsesWith but dangerous.
84 // Only use when in type resolution situations!
85 void uncheckedReplaceAllUsesWith(Value *V);
87 //----------------------------------------------------------------------
88 // Methods for handling the vector of uses of this Value.
90 typedef UseListIteratorWrapper use_iterator;
91 typedef UseListConstIteratorWrapper use_const_iterator;
93 unsigned use_size() const { return Uses.size(); }
94 bool use_empty() const { return Uses.empty(); }
95 use_iterator use_begin() { return Uses.begin(); }
96 use_const_iterator use_begin() const { return Uses.begin(); }
97 use_iterator use_end() { return Uses.end(); }
98 use_const_iterator use_end() const { return Uses.end(); }
99 User *use_back() { return Uses.back().getUser(); }
100 const User *use_back() const { return Uses.back().getUser(); }
102 /// hasOneUse - Return true if there is exactly one user of this value. This
103 /// is specialized because it is a common request and does not require
104 /// traversing the whole use list.
106 bool hasOneUse() const {
107 iplist<Use>::const_iterator I = Uses.begin(), E = Uses.end();
108 if (I == E) return false;
112 /// addUse/killUse - These two methods should only be used by the Use class.
114 void addUse(Use &U) { Uses.push_back(&U); }
115 void killUse(Use &U) { Uses.remove(&U); }
117 /// getValueType - Return an ID for the concrete type of this object. This is
118 /// used to implement the classof checks. This should not be used for any
119 /// other purpose, as the values may change as LLVM evolves. Also, note that
120 /// starting with the InstructionVal value, the value stored is actually the
121 /// Instruction opcode, so there are more than just these values possible here
122 /// (and Instruction must be last).
125 ArgumentVal, // This is an instance of Argument
126 BasicBlockVal, // This is an instance of BasicBlock
127 FunctionVal, // This is an instance of Function
128 GlobalVariableVal, // This is an instance of GlobalVariable
129 UndefValueVal, // This is an instance of UndefValue
130 ConstantExprVal, // This is an instance of ConstantExpr
131 ConstantAggregateZeroVal, // This is an instance of ConstantAggregateNull
132 SimpleConstantVal, // This is some other type of Constant
133 InstructionVal, // This is an instance of Instruction
134 ValueListVal // This is for bcreader, a special ValTy
136 unsigned getValueType() const {
140 // Methods for support type inquiry through isa, cast, and dyn_cast:
141 static inline bool classof(const Value *V) {
142 return true; // Values are always values.
145 /// getRawType - This should only be used to implement the vmcore library.
147 const Type *getRawType() const { return Ty.getRawType(); }
150 /// FIXME: this is a gross hack, needed by another gross hack. Eliminate!
151 void setValueType(unsigned VT) { SubclassID = VT; }
152 friend class Instruction;
155 inline std::ostream &operator<<(std::ostream &OS, const Value &V) {
161 inline User *UseListIteratorWrapper::operator*() const {
162 return Super::operator*().getUser();
165 inline const User *UseListConstIteratorWrapper::operator*() const {
166 return Super::operator*().getUser();
170 Use::Use(Value *v, User *user) : Val(v), U(user) {
171 if (Val) Val->addUse(*this);
174 Use::Use(const Use &u) : Val(u.Val), U(u.U) {
175 if (Val) Val->addUse(*this);
179 if (Val) Val->killUse(*this);
182 void Use::set(Value *V) {
183 if (Val) Val->killUse(*this);
185 if (V) V->addUse(*this);
189 // isa - Provide some specializations of isa so that we don't have to include
190 // the subtype header files to test to see if the value is a subclass...
192 template <> inline bool isa_impl<Constant, Value>(const Value &Val) {
193 return Val.getValueType() == Value::SimpleConstantVal ||
194 Val.getValueType() == Value::FunctionVal ||
195 Val.getValueType() == Value::GlobalVariableVal ||
196 Val.getValueType() == Value::ConstantExprVal ||
197 Val.getValueType() == Value::ConstantAggregateZeroVal ||
198 Val.getValueType() == Value::UndefValueVal;
200 template <> inline bool isa_impl<Argument, Value>(const Value &Val) {
201 return Val.getValueType() == Value::ArgumentVal;
203 template <> inline bool isa_impl<Instruction, Value>(const Value &Val) {
204 return Val.getValueType() >= Value::InstructionVal;
206 template <> inline bool isa_impl<BasicBlock, Value>(const Value &Val) {
207 return Val.getValueType() == Value::BasicBlockVal;
209 template <> inline bool isa_impl<Function, Value>(const Value &Val) {
210 return Val.getValueType() == Value::FunctionVal;
212 template <> inline bool isa_impl<GlobalVariable, Value>(const Value &Val) {
213 return Val.getValueType() == Value::GlobalVariableVal;
215 template <> inline bool isa_impl<GlobalValue, Value>(const Value &Val) {
216 return isa<GlobalVariable>(Val) || isa<Function>(Val);
219 } // End llvm namespace