| // Copyright 2019 The SwiftShader Authors. All Rights Reserved. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| #ifndef sw_Memset_hpp |
| #define sw_Memset_hpp |
| |
| #include <cstring> |
| #include <type_traits> |
| |
| namespace sw { |
| |
| // Helper class for clearing the memory of objects at construction. |
| // Useful as the first base class of cache keys which may contain padding |
| // bytes or bits otherwise left uninitialized. |
| template<class T> |
| struct Memset |
| { |
| Memset(T *object, int val) |
| { |
| static_assert(std::is_base_of<Memset<T>, T>::value, "Memset<T> must only clear the memory of a type of which it is a base class"); |
| |
| // GCC 8+ warns that |
| // "‘void* memset(void*, int, size_t)’ clearing an object of non-trivial type ‘T’; |
| // use assignment or value-initialization instead [-Werror=class-memaccess]" |
| // This is benign iff it happens before any of the base or member constructrs are called. |
| #if defined(__GNUC__) && (__GNUC__ >= 8) |
| # pragma GCC diagnostic push |
| # pragma GCC diagnostic ignored "-Wclass-memaccess" |
| #endif |
| |
| memset(object, 0, sizeof(T)); |
| |
| #if defined(__GNUC__) && (__GNUC__ >= 8) |
| # pragma GCC diagnostic pop |
| #endif |
| } |
| }; |
| |
| } // namespace sw |
| |
| #endif // sw_Memset_hpp |