Value.h revision 48486893f46d2e12e926682a3ecb908716bc66c4 
1//===-- llvm/Value.h - Definition of the Value class ------------*- C++ -*-===//
2//
3// This file defines the very important Value class.  This is subclassed by a
4// bunch of other important classes, like Instruction, Function, Type, etc...
5//
6// This file also defines the Use<> template for users of value.
7//
8//===----------------------------------------------------------------------===//
9
10#ifndef LLVM_VALUE_H
11#define LLVM_VALUE_H
12
13#include "llvm/AbstractTypeUser.h"
14#include "Support/Annotation.h"
15#include "Support/Casting.h"
16#include <iostream>
17#include <vector>
18
19class User;
20class Type;
21class Constant;
22class Argument;
23class Instruction;
24class BasicBlock;
25class GlobalValue;
26class Function;
27class GlobalVariable;
28class SymbolTable;
29
30//===----------------------------------------------------------------------===//
31//                                 Value Class
32//===----------------------------------------------------------------------===//
33
34/// Value - The base class of all values computed by a program that may be used
35/// as operands to other values.
36///
37class Value : public Annotable,         // Values are annotable
38	      public AbstractTypeUser { // Values use potentially abstract types
39public:
40  enum ValueTy {
41    TypeVal,                // This is an instance of Type
42    ConstantVal,            // This is an instance of Constant
43    ArgumentVal,            // This is an instance of Argument
44    InstructionVal,         // This is an instance of Instruction
45    BasicBlockVal,          // This is an instance of BasicBlock
46    FunctionVal,            // This is an instance of Function
47    GlobalVariableVal,      // This is an instance of GlobalVariable
48  };
49
50private:
51  std::vector<User *> Uses;
52  std::string Name;
53  PATypeHandle Ty;
54  ValueTy VTy;
55
56  void operator=(const Value &);     // Do not implement
57  Value(const Value &);              // Do not implement
58public:
59  Value(const Type *Ty, ValueTy vty, const std::string &name = "");
60  virtual ~Value();
61
62  /// dump - Support for debugging, callable in GDB: V->dump()
63  //
64  void dump() const;
65
66  /// print - Implement operator<< on Value...
67  ///
68  virtual void print(std::ostream &O) const = 0;
69
70  /// All values are typed, get the type of this value.
71  ///
72  inline const Type *getType() const { return Ty; }
73
74  // All values can potentially be named...
75  inline bool               hasName() const { return Name != ""; }
76  inline const std::string &getName() const { return Name; }
77
78  virtual void setName(const std::string &name, SymbolTable * = 0) {
79    Name = name;
80  }
81
82  /// getValueType - Return the immediate subclass of this Value.
83  ///
84  inline ValueTy getValueType() const { return VTy; }
85
86  /// replaceAllUsesWith - Go through the uses list for this definition and make
87  /// each use point to "V" instead of "this".  After this completes, 'this's
88  /// use list is guaranteed to be empty.
89  ///
90  void replaceAllUsesWith(Value *V);
91
92  // uncheckedReplaceAllUsesWith - Just like replaceAllUsesWith but dangerous.
93  // Only use when in type resolution situations!
94  void uncheckedReplaceAllUsesWith(Value *V);
95
96  /// refineAbstractType - This function is implemented because we use
97  /// potentially abstract types, and these types may be resolved to more
98  /// concrete types after we are constructed.
99  ///
100  virtual void refineAbstractType(const DerivedType *OldTy, const Type *NewTy);
101
102  //----------------------------------------------------------------------
103  // Methods for handling the vector of uses of this Value.
104  //
105  typedef std::vector<User*>::iterator       use_iterator;
106  typedef std::vector<User*>::const_iterator use_const_iterator;
107
108  inline unsigned           use_size()  const { return Uses.size();  }
109  inline bool               use_empty() const { return Uses.empty(); }
110  inline use_iterator       use_begin()       { return Uses.begin(); }
111  inline use_const_iterator use_begin() const { return Uses.begin(); }
112  inline use_iterator       use_end()         { return Uses.end();   }
113  inline use_const_iterator use_end()   const { return Uses.end();   }
114  inline User              *use_back()        { return Uses.back();  }
115  inline const User        *use_back()  const { return Uses.back();  }
116
117  /// addUse/killUse - These two methods should only be used by the Use class
118  /// below.
119  inline void addUse(User *I)      { Uses.push_back(I); }
120  void killUse(User *I);
121};
122
123inline std::ostream &operator<<(std::ostream &OS, const Value *V) {
124  if (V == 0)
125    OS << "<null> value!\n";
126  else
127    V->print(OS);
128  return OS;
129}
130
131inline std::ostream &operator<<(std::ostream &OS, const Value &V) {
132  V.print(OS);
133  return OS;
134}
135
136
137//===----------------------------------------------------------------------===//
138//                                  Use Class
139//===----------------------------------------------------------------------===//
140
141// Use is here to make keeping the "use" list of a Value up-to-date really easy.
142//
143class Use {
144  Value *Val;
145  User *U;
146public:
147  inline Use(Value *v, User *user) {
148    Val = v; U = user;
149    if (Val) Val->addUse(U);
150  }
151
152  inline Use(const Use &user) {
153    Val = 0;
154    U = user.U;
155    operator=(user.Val);
156  }
157  inline ~Use() { if (Val) Val->killUse(U); }
158  inline operator Value*() const { return Val; }
159
160  inline Value *operator=(Value *V) {
161    if (Val) Val->killUse(U);
162    Val = V;
163    if (V) V->addUse(U);
164    return V;
165  }
166
167  inline       Value *operator->()       { return Val; }
168  inline const Value *operator->() const { return Val; }
169
170  inline       Value *get()       { return Val; }
171  inline const Value *get() const { return Val; }
172
173  inline const Use &operator=(const Use &user) {
174    if (Val) Val->killUse(U);
175    Val = user.Val;
176    Val->addUse(U);
177    return *this;
178  }
179};
180
181template<> struct simplify_type<Use> {
182  typedef Value* SimpleType;
183
184  static SimpleType getSimplifiedValue(const Use &Val) {
185    return (SimpleType)Val.get();
186  }
187};
188template<> struct simplify_type<const Use> {
189  typedef Value* SimpleType;
190
191  static SimpleType getSimplifiedValue(const Use &Val) {
192    return (SimpleType)Val.get();
193  }
194};
195
196// isa - Provide some specializations of isa so that we don't have to include
197// the subtype header files to test to see if the value is a subclass...
198//
199template <> inline bool isa_impl<Type, Value>(const Value &Val) {
200  return Val.getValueType() == Value::TypeVal;
201}
202template <> inline bool isa_impl<Constant, Value>(const Value &Val) {
203  return Val.getValueType() == Value::ConstantVal;
204}
205template <> inline bool isa_impl<Argument, Value>(const Value &Val) {
206  return Val.getValueType() == Value::ArgumentVal;
207}
208template <> inline bool isa_impl<Instruction, Value>(const Value &Val) {
209  return Val.getValueType() == Value::InstructionVal;
210}
211template <> inline bool isa_impl<BasicBlock, Value>(const Value &Val) {
212  return Val.getValueType() == Value::BasicBlockVal;
213}
214template <> inline bool isa_impl<Function, Value>(const Value &Val) {
215  return Val.getValueType() == Value::FunctionVal;
216}
217template <> inline bool isa_impl<GlobalVariable, Value>(const Value &Val) {
218  return Val.getValueType() == Value::GlobalVariableVal;
219}
220template <> inline bool isa_impl<GlobalValue, Value>(const Value &Val) {
221  return isa<GlobalVariable>(Val) || isa<Function>(Val);
222}
223
224#endif
225