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"
37 //===----------------------------------------------------------------------===//
39 //===----------------------------------------------------------------------===//
41 /// Value - The base class of all values computed by a program that may be used
42 /// as operands to other values.
45 unsigned short SubclassID; // Subclass identifier (for isa/dyn_cast)
47 /// SubclassData - This member is defined by this class, but is not used for
48 /// anything. Subclasses can use it to hold whatever state they find useful.
49 /// This field is initialized to zero by the ctor.
50 unsigned short SubclassData;
55 friend class ValueSymbolTable; // Allow ValueSymbolTable to directly mod Name.
56 friend class SymbolTable; // Allow SymbolTable to directly poke Name.
59 void operator=(const Value &); // Do not implement
60 Value(const Value &); // Do not implement
63 Value(const Type *Ty, unsigned scid, const std::string &name = "");
66 /// dump - Support for debugging, callable in GDB: V->dump()
68 virtual void dump() const;
70 /// print - Implement operator<< on Value...
72 virtual void print(std::ostream &O) const = 0;
74 /// All values are typed, get the type of this value.
76 inline const Type *getType() const { return Ty; }
78 // All values can potentially be named...
79 inline bool hasName() const { return !Name.empty(); }
80 inline const std::string &getName() const { return Name; }
82 void setName(const std::string &name);
84 /// replaceAllUsesWith - Go through the uses list for this definition and make
85 /// each use point to "V" instead of "this". After this completes, 'this's
86 /// use list is guaranteed to be empty.
88 void replaceAllUsesWith(Value *V);
90 // uncheckedReplaceAllUsesWith - Just like replaceAllUsesWith but dangerous.
91 // Only use when in type resolution situations!
92 void uncheckedReplaceAllUsesWith(Value *V);
94 //----------------------------------------------------------------------
95 // Methods for handling the vector of uses of this Value.
97 typedef value_use_iterator<User> use_iterator;
98 typedef value_use_iterator<const User> use_const_iterator;
100 bool use_empty() const { return UseList == 0; }
101 use_iterator use_begin() { return use_iterator(UseList); }
102 use_const_iterator use_begin() const { return use_const_iterator(UseList); }
103 use_iterator use_end() { return use_iterator(0); }
104 use_const_iterator use_end() const { return use_const_iterator(0); }
105 User *use_back() { return *use_begin(); }
106 const User *use_back() const { return *use_begin(); }
108 /// hasOneUse - Return true if there is exactly one user of this value. This
109 /// is specialized because it is a common request and does not require
110 /// traversing the whole use list.
112 bool hasOneUse() const {
113 use_const_iterator I = use_begin(), E = use_end();
114 if (I == E) return false;
118 /// hasNUses - Return true if this Value has exactly N users.
120 bool hasNUses(unsigned N) const;
122 /// hasNUsesOrMore - Return true if this value has N users or more. This is
123 /// logically equivalent to getNumUses() >= N.
125 bool hasNUsesOrMore(unsigned N) const;
127 /// getNumUses - This method computes the number of uses of this Value. This
128 /// is a linear time operation. Use hasOneUse, hasNUses, or hasMoreThanNUses
129 /// to check for specific values.
130 unsigned getNumUses() const;
132 /// addUse/killUse - These two methods should only be used by the Use class.
134 void addUse(Use &U) { U.addToList(&UseList); }
136 /// getValueType - Return an ID for the concrete type of this object. This is
137 /// used to implement the classof checks. This should not be used for any
138 /// other purpose, as the values may change as LLVM evolves. Also, note that
139 /// starting with the InstructionVal value, the value stored is actually the
140 /// Instruction opcode, so there are more than just these values possible here
141 /// (and Instruction must be last).
144 ArgumentVal, // This is an instance of Argument
145 BasicBlockVal, // This is an instance of BasicBlock
146 FunctionVal, // This is an instance of Function
147 GlobalVariableVal, // This is an instance of GlobalVariable
148 UndefValueVal, // This is an instance of UndefValue
149 ConstantExprVal, // This is an instance of ConstantExpr
150 ConstantAggregateZeroVal, // This is an instance of ConstantAggregateNull
151 ConstantBoolVal, // This is an instance of ConstantBool
152 ConstantSIntVal, // This is an instance of ConstantSInt
153 ConstantUIntVal, // This is an instance of ConstantUInt
154 ConstantFPVal, // This is an instance of ConstantFP
155 ConstantArrayVal, // This is an instance of ConstantArray
156 ConstantStructVal, // This is an instance of ConstantStruct
157 ConstantPackedVal, // This is an instance of ConstantPacked
158 ConstantPointerNullVal, // This is an instance of ConstantPointerNull
159 InlineAsmVal, // This is an instance of InlineAsm
160 InstructionVal, // This is an instance of Instruction
163 ConstantFirstVal = FunctionVal,
164 ConstantLastVal = ConstantPointerNullVal
166 unsigned getValueType() const {
170 // Methods for support type inquiry through isa, cast, and dyn_cast:
171 static inline bool classof(const Value *) {
172 return true; // Values are always values.
175 /// getRawType - This should only be used to implement the vmcore library.
177 const Type *getRawType() const { return Ty.getRawType(); }
180 /// FIXME: this is a gross hack, needed by another gross hack. Eliminate!
181 void setValueType(unsigned short VT) { SubclassID = VT; }
182 friend class Instruction;
185 inline std::ostream &operator<<(std::ostream &OS, const Value &V) {
190 void Use::init(Value *v, User *user) {
193 if (Val) Val->addUse(*this);
197 if (Val) removeFromList();
200 void Use::set(Value *V) {
201 if (Val) removeFromList();
203 if (V) V->addUse(*this);
207 // isa - Provide some specializations of isa so that we don't have to include
208 // the subtype header files to test to see if the value is a subclass...
210 template <> inline bool isa_impl<Constant, Value>(const Value &Val) {
211 return Val.getValueType() >= Value::ConstantFirstVal &&
212 Val.getValueType() <= Value::ConstantLastVal;
214 template <> inline bool isa_impl<Argument, Value>(const Value &Val) {
215 return Val.getValueType() == Value::ArgumentVal;
217 template <> inline bool isa_impl<InlineAsm, Value>(const Value &Val) {
218 return Val.getValueType() == Value::InlineAsmVal;
220 template <> inline bool isa_impl<Instruction, Value>(const Value &Val) {
221 return Val.getValueType() >= Value::InstructionVal;
223 template <> inline bool isa_impl<BasicBlock, Value>(const Value &Val) {
224 return Val.getValueType() == Value::BasicBlockVal;
226 template <> inline bool isa_impl<Function, Value>(const Value &Val) {
227 return Val.getValueType() == Value::FunctionVal;
229 template <> inline bool isa_impl<GlobalVariable, Value>(const Value &Val) {
230 return Val.getValueType() == Value::GlobalVariableVal;
232 template <> inline bool isa_impl<GlobalValue, Value>(const Value &Val) {
233 return isa<GlobalVariable>(Val) || isa<Function>(Val);
236 } // End llvm namespace