1 //===-- llvm/Constant.h - Constant class definition -------------*- 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 contains the declaration of the Constant class.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_CONSTANT_H
15 #define LLVM_CONSTANT_H
17 #include "llvm/User.h"
21 class Constant : public User {
23 inline Constant(const Type *Ty, ValueTy vty = Value::SimpleConstantVal,
24 const std::string& Name = "")
25 : User(Ty, vty, Name) {}
28 void destroyConstantImpl();
30 // setName - Specialize setName to handle symbol table majik...
31 virtual void setName(const std::string &name, SymbolTable *ST = 0);
33 /// Static constructor to get a '0' constant of arbitrary type...
35 static Constant *getNullValue(const Type *Ty);
37 /// isNullValue - Return true if this is the value that would be returned by
39 virtual bool isNullValue() const = 0;
41 virtual void print(std::ostream &O) const;
43 // Specialize get/setOperand for Constant's as their operands are always
45 Constant *getOperand(unsigned i) {
46 return static_cast<Constant*>(User::getOperand(i));
48 const Constant *getOperand(unsigned i) const {
49 return static_cast<const Constant*>(User::getOperand(i));
51 void setOperand(unsigned i, Constant *C) {
52 User::setOperand(i, C);
55 /// destroyConstant - Called if some element of this constant is no longer
56 /// valid. At this point only other constants may be on the use_list for this
57 /// constant. Any constants on our Use list must also be destroy'd. The
58 /// implementation must be sure to remove the constant from the list of
59 /// available cached constants. Implementations should call
60 /// destroyConstantImpl as the last thing they do, to destroy all users and
62 virtual void destroyConstant() { assert(0 && "Not reached!"); }
64 //// Methods for support type inquiry through isa, cast, and dyn_cast:
65 static inline bool classof(const Constant *) { return true; }
66 static inline bool classof(const GlobalValue *) { return true; }
67 static inline bool classof(const Value *V) {
68 return V->getValueType() == Value::SimpleConstantVal ||
69 V->getValueType() == Value::ConstantExprVal ||
70 V->getValueType() == Value::ConstantAggregateZeroVal ||
71 V->getValueType() == Value::FunctionVal ||
72 V->getValueType() == Value::GlobalVariableVal;
75 /// replaceUsesOfWithOnConstant - This method is a special form of
76 /// User::replaceUsesOfWith (which does not work on constants) that does work
77 /// on constants. Basically this method goes through the trouble of building
78 /// a new constant that is equivalent to the current one, with all uses of
79 /// From replaced with uses of To. After this construction is completed, all
80 /// of the users of 'this' are replaced to use the new constant, and then
81 /// 'this' is deleted. In general, you should not call this method, instead,
82 /// use Value::replaceAllUsesWith, which automatically dispatches to this
85 virtual void replaceUsesOfWithOnConstant(Value *From, Value *To,
86 bool DisableChecking = false) {
87 // Provide a default implementation for constants (like integers) that
88 // cannot use any other values. This cannot be called at runtime, but needs
89 // to be here to avoid link errors.
90 assert(getNumOperands() == 0 && "replaceUsesOfWithOnConstant must be "
91 "implemented for all constants that have operands!");
92 assert(0 && "Constants that do not have operands cannot be using 'From'!");
96 } // End llvm namespace