1//===- DerivedUser.h - Base for non-IR Users --------------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#ifndef LLVM_IR_DERIVEDUSER_H
10#define LLVM_IR_DERIVEDUSER_H
11
12#include "llvm/IR/User.h"
13
14namespace llvm {
15
16class Type;
17class Use;
18
19/// Extension point for the Value hierarchy. All classes outside of lib/IR
20/// that wish to inherit from User should instead inherit from DerivedUser
21/// instead. Inheriting from this class is discouraged.
22///
23/// Generally speaking, Value is the base of a closed class hierarchy
24/// that can't be extended by code outside of lib/IR. This class creates a
25/// loophole that allows classes outside of lib/IR to extend User to leverage
26/// its use/def list machinery.
27class DerivedUser : public User {
28protected:
29 using DeleteValueTy = void (*)(DerivedUser *);
30
31private:
32 friend class Value;
33
34 DeleteValueTy DeleteValue;
35
36public:
37 DerivedUser(Type *Ty, unsigned VK, Use *U, unsigned NumOps,
38 DeleteValueTy DeleteValue)
39 : User(Ty, VK, U, NumOps), DeleteValue(DeleteValue) {}
40};
41
42} // end namespace llvm
43
44#endif // LLVM_IR_DERIVEDUSER_H
45