1 //===-- llvm/Constant.h - Constant class definition --------------*- C++ -*--=//
3 // This file contains the declaration of the Constant class.
5 //===----------------------------------------------------------------------===//
7 #ifndef LLVM_CONSTANT_H
8 #define LLVM_CONSTANT_H
11 #include "llvm/User.h"
13 class Constant : public User {
15 inline Constant(const Type *Ty) : User(Ty, Value::ConstantVal) {}
18 void destroyConstantImpl();
20 // setName - Specialize setName to handle symbol table majik...
21 virtual void setName(const std::string &name, SymbolTable *ST = 0);
23 /// Static constructor to get a '0' constant of arbitrary type...
25 static Constant *getNullValue(const Type *Ty);
27 /// isNullValue - Return true if this is the value that would be returned by
29 virtual bool isNullValue() const = 0;
31 virtual void print(std::ostream &O) const;
33 /// isConstantExpr - Return true if this is a ConstantExpr
35 virtual bool isConstantExpr() const { return false; }
38 /// destroyConstant - Called if some element of this constant is no longer
39 /// valid. At this point only other constants may be on the use_list for this
40 /// constant. Any constants on our Use list must also be destroy'd. The
41 /// implementation must be sure to remove the constant from the list of
42 /// available cached constants. Implementations should call
43 /// destroyConstantImpl as the last thing they do, to destroy all users and
46 /// Note that this call is only valid on non-primitive constants: You cannot
47 /// destroy an integer constant for example. This API is used to delete
48 /// constants that have ConstantPointerRef's embeded in them when the module
49 /// is deleted, and it is used by GlobalDCE to remove ConstantPointerRefs that
50 /// are unneeded, allowing globals to be DCE'd.
52 virtual void destroyConstant() { assert(0 && "Not reached!"); }
55 //// Methods for support type inquiry through isa, cast, and dyn_cast:
56 static inline bool classof(const Constant *) { return true; }
57 static inline bool classof(const Value *V) {
58 return V->getValueType() == Value::ConstantVal;
61 /// replaceUsesOfWithOnConstant - This method is a special form of
62 /// User::replaceUsesOfWith (which does not work on constants) that does work
63 /// on constants. Basically this method goes through the trouble of building
64 /// a new constant that is equivalent to the current one, with all uses of
65 /// From replaced with uses of To. After this construction is completed, all
66 /// of the users of 'this' are replaced to use the new constant, and then
67 /// 'this' is deleted. In general, you should not call this method, instead,
68 /// use Value::replaceAllUsesWith, which automatically dispatches to this
71 virtual void replaceUsesOfWithOnConstant(Value *From, Value *To) {
72 // Provide a default implementation for constants (like integers) that
73 // cannot use any other values. This cannot be called at runtime, but needs
74 // to be here to avoid link errors.
75 assert(getNumOperands() == 0 && "replaceUsesOfWithOnConstant must be "
76 "implemented for all constants that have operands!");
77 assert(0 && "Constants that do not have operands cannot be using 'From'!");
80 // WARNING: Only to be used by Bytecode & Assembly Parsers! USER CODE SHOULD
82 // Returns the number of uses of OldV that were replaced.
83 unsigned mutateReferences(Value* OldV, Value *NewV);