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llvm-mirror/include/llvm/Constant.h
Chris Lattner 8f4f2153e5 - ConstantPointerRefs are now automatically removed from the module table
when they are destroyed, which makes Constant::destroyConstant an actually
    useful external interface.  Expose these methods publicly.
  - Implement destroyConstant on ConstPointerNull so that destroyConstant can
    be used on any derived type constant safely.

llvm-svn: 3378
2002-08-18 00:39:59 +00:00

66 lines
2.4 KiB
C++

//===-- llvm/Constant.h - Constant class definition --------------*- C++ -*--=//
//
// This file contains the declaration of the Constant class.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CONSTANT_H
#define LLVM_CONSTANT_H
#include "llvm/User.h"
class Constant : public User {
protected:
inline Constant(const Type *Ty) : User(Ty, Value::ConstantVal) {}
~Constant() {}
void destroyConstantImpl();
public:
// Specialize setName to handle symbol table majik...
virtual void setName(const std::string &name, SymbolTable *ST = 0);
// Static constructor to get a '0' constant of arbitrary type...
static Constant *getNullValue(const Type *Ty);
// isNullValue - Return true if this is the value that would be returned by
// getNullValue.
virtual bool isNullValue() const = 0;
virtual void print(std::ostream &O) const;
// isConstantExpr - Return true if this is a ConstantExpr
virtual bool isConstantExpr() const { return false; }
// destroyConstant - Called if some element of this constant is no longer
// valid. At this point only other constants may be on the use_list for this
// constant. Any constants on our Use list must also be destroy'd. The
// implementation must be sure to remove the constant from the list of
// available cached constants. Implementations should call
// destroyConstantImpl as the last thing they do, to destroy all users and
// delete this.
//
// Note that this call is only valid on non-primitive constants: You cannot
// destroy an integer constant for example. This API is used to delete
// constants that have ConstantPointerRef's embeded in them when the module is
// deleted, and it is used by GlobalDCE to remove ConstantPointerRefs that are
// unneeded, allowing globals to be DCE'd.
//
virtual void destroyConstant() { assert(0 && "Not reached!"); }
// Methods for support type inquiry through isa, cast, and dyn_cast:
static inline bool classof(const Constant *) { return true; }
static inline bool classof(const Value *V) {
return V->getValueType() == Value::ConstantVal;
}
// WARNING: Only to be used by Bytecode & Assembly Parsers! USER CODE SHOULD
// NOT USE THIS!!
// Returns the number of uses of OldV that were replaced.
virtual unsigned mutateReferences(Value* OldV, Value *NewV) { return 0; }
// END WARNING!!
};
#endif