1 //===-- DerivedUser.h - Base for non-IR Users -------------------*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 10 #ifndef LLVM_IR_DERIVEDUSER_H 11 #define LLVM_IR_DERIVEDUSER_H 12 13 #include "llvm/IR/User.h" 14 15 namespace llvm { 16 17 /// Extension point for the Value hierarchy. All classes outside of lib/IR 18 /// that wish to inherit from User should instead inherit from DerivedUser 19 /// instead. Inheriting from this class is discouraged. 20 /// 21 /// Generally speaking, Value is the base of a closed class hierarchy 22 /// that can't be extended by code outside of lib/IR. This class creates a 23 /// loophole that allows classes outside of lib/IR to extend User to leverage 24 /// its use/def list machinery. 25 class DerivedUser : public User { 26 protected: 27 typedef void (*DeleteValueTy)(DerivedUser *); 28 29 private: 30 friend Value; 31 DeleteValueTy DeleteValue; 32 33 public: 34 DerivedUser(Type *Ty, unsigned VK, Use *U, unsigned NumOps, 35 DeleteValueTy DeleteValue) 36 : User(Ty, VK, U, NumOps), DeleteValue(DeleteValue) {} 37 }; 38 39 } // namespace llvm 40 41 #endif // LLVM_IR_DERIVEDUSER_H 42
