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 | |
14 | namespace llvm { |
15 | |
16 | class Type; |
17 | class 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. |
27 | class DerivedUser : public User { |
28 | protected: |
29 | using DeleteValueTy = void (*)(DerivedUser *); |
30 | |
31 | private: |
32 | friend class Value; |
33 | |
34 | DeleteValueTy DeleteValue; |
35 | |
36 | public: |
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 | |