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 Constant(const Type *Ty, ValueTy vty, Use *Ops, unsigned NumOps,
24 const std::string& Name = "")
25 : User(Ty, vty, Ops, NumOps, Name) {}
27 void destroyConstantImpl();
29 /// Static constructor to get a '0' constant of arbitrary type...
31 static Constant *getNullValue(const Type *Ty);
33 /// isNullValue - Return true if this is the value that would be returned by
35 virtual bool isNullValue() const = 0;
37 virtual void print(std::ostream &O) const;
39 // Specialize get/setOperand for Constant's as their operands are always
41 Constant *getOperand(unsigned i) {
42 return static_cast<Constant*>(User::getOperand(i));
44 const Constant *getOperand(unsigned i) const {
45 return static_cast<const Constant*>(User::getOperand(i));
47 void setOperand(unsigned i, Constant *C) {
48 User::setOperand(i, C);
51 /// destroyConstant - Called if some element of this constant is no longer
52 /// valid. At this point only other constants may be on the use_list for this
53 /// constant. Any constants on our Use list must also be destroy'd. The
54 /// implementation must be sure to remove the constant from the list of
55 /// available cached constants. Implementations should call
56 /// destroyConstantImpl as the last thing they do, to destroy all users and
58 virtual void destroyConstant() { assert(0 && "Not reached!"); }
60 //// Methods for support type inquiry through isa, cast, and dyn_cast:
61 static inline bool classof(const Constant *) { return true; }
62 static inline bool classof(const GlobalValue *) { return true; }
63 static inline bool classof(const Value *V) {
64 return V->getValueType() == Value::SimpleConstantVal ||
65 V->getValueType() == Value::ConstantExprVal ||
66 V->getValueType() == Value::ConstantAggregateZeroVal ||
67 V->getValueType() == Value::FunctionVal ||
68 V->getValueType() == Value::GlobalVariableVal ||
69 V->getValueType() == Value::UndefValueVal;
72 /// replaceUsesOfWithOnConstant - This method is a special form of
73 /// User::replaceUsesOfWith (which does not work on constants) that does work
74 /// on constants. Basically this method goes through the trouble of building
75 /// a new constant that is equivalent to the current one, with all uses of
76 /// From replaced with uses of To. After this construction is completed, all
77 /// of the users of 'this' are replaced to use the new constant, and then
78 /// 'this' is deleted. In general, you should not call this method, instead,
79 /// use Value::replaceAllUsesWith, which automatically dispatches to this
82 virtual void replaceUsesOfWithOnConstant(Value *From, Value *To,
83 bool DisableChecking = false) {
84 // Provide a default implementation for constants (like integers) that
85 // cannot use any other values. This cannot be called at runtime, but needs
86 // to be here to avoid link errors.
87 assert(getNumOperands() == 0 && "replaceUsesOfWithOnConstant must be "
88 "implemented for all constants that have operands!");
89 assert(0 && "Constants that do not have operands cannot be using 'From'!");
92 /// clearAllValueMaps - This method frees all internal memory used by the
93 /// constant subsystem, which can be used in environments where this memory
94 /// is otherwise reported as a leak.
95 static void clearAllValueMaps();
98 } // End llvm namespace