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213516ef | 1 | /* Copyright (C) 2022-2023 Free Software Foundation, Inc. |
11da1b13 AB |
2 | |
3 | This file is part of GDB. | |
4 | ||
5 | This program is free software; you can redistribute it and/or modify | |
6 | it under the terms of the GNU General Public License as published by | |
7 | the Free Software Foundation; either version 3 of the License, or | |
8 | (at your option) any later version. | |
9 | ||
10 | This program is distributed in the hope that it will be useful, | |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | GNU General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU General Public License | |
16 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ | |
17 | ||
18 | #ifndef COMMON_GDB_CHECKED_DYNAMIC_CAST_H | |
19 | #define COMMON_GDB_CHECKED_DYNAMIC_CAST_H | |
20 | ||
21 | #include "gdbsupport/traits.h" | |
22 | ||
23 | namespace gdb | |
24 | { | |
25 | ||
26 | /* This function can be used in place of static_cast when casting between | |
27 | pointers of polymorphic types. The benefit of using this call is that, | |
28 | when compiling in developer mode, dynamic_cast will be used to validate | |
29 | the cast. This use of dynamic_cast is why this function will only | |
30 | work for polymorphic types. | |
31 | ||
32 | In non-developer (i.e. production) builds, the dynamic_cast is replaced | |
33 | with a static_cast which is usually significantly faster. */ | |
34 | ||
35 | template<typename T, typename V> | |
36 | T | |
37 | checked_static_cast (V *v) | |
38 | { | |
39 | /* We only support casting to pointer types. */ | |
40 | static_assert (std::is_pointer<T>::value, "target must be a pointer type"); | |
41 | ||
42 | /* Check for polymorphic types explicitly in case we're in release mode. */ | |
43 | static_assert (std::is_polymorphic<V>::value, "types must be polymorphic"); | |
44 | ||
45 | /* Figure out the type that T points to. */ | |
46 | using T_no_P = typename std::remove_pointer<T>::type; | |
47 | ||
48 | /* In developer mode this cast uses dynamic_cast to confirm at run-time | |
49 | that the cast from V* to T is valid. However, we can catch some | |
50 | mistakes at compile time, this assert prevents anything other than | |
51 | downcasts, or casts to same type. */ | |
52 | static_assert (std::is_base_of<V, T_no_P>::value | |
53 | || std::is_base_of<T_no_P, V>::value, | |
54 | "types must be related"); | |
55 | ||
56 | #ifdef DEVELOPMENT | |
57 | T result = dynamic_cast<T> (v); | |
58 | gdb_assert (result != nullptr); | |
59 | #else | |
60 | T result = static_cast<T> (v); | |
61 | #endif | |
62 | ||
63 | return result; | |
64 | } | |
65 | ||
66 | } | |
67 | ||
68 | #endif /* COMMON_GDB_CHECKED_DYNAMIC_CAST_H */ |