1 // Copyright 2017 The Gemmlowp Authors. All Rights Reserved. 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // http://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 15 // pthread_everywhere.h: Either includes <pthread.h> or implements a 16 // subset of pthread functionality on top of C++11 <thread> for portability. 17 18 #ifndef GEMMLOWP_PROFILING_PTHREAD_EVERYWHERE_H_ 19 #define GEMMLOWP_PROFILING_PTHREAD_EVERYWHERE_H_ 20 21 #ifndef _WIN32 22 #define GEMMLOWP_USE_PTHREAD 23 #endif 24 25 #if defined GEMMLOWP_USE_PTHREAD 26 #include <pthread.h> 27 #else 28 // Implement a small subset of pthread on top of C++11 threads. 29 // The function signatures differ from true pthread functions in two ways: 30 // - True pthread functions return int error codes, ours return void. 31 // Rationale: the c++11 <thread> equivalent functions return void 32 // and use exceptions to report errors; we don't want to deal with 33 // exceptions in this code, so we couldn't meaningfully return errors 34 // in the polyfill. Also, the gemmlowp code using these pthread functions 35 // never checks their return values anyway. 36 // - True pthread *_create/*_init functions take pointers to 'attribute' 37 // structs; ours take nullptr_t. That is because gemmlowp always passes 38 // nullptr at the moment, so any support we would code for non-null 39 // attribs would be unused. 40 #include <condition_variable> 41 #include <cstddef> 42 #include <mutex> 43 #include <thread> 44 namespace gemmlowp { 45 using pthread_t = std::thread *; 46 using pthread_mutex_t = std::mutex *; 47 using pthread_cond_t = std::condition_variable *; 48 inline void pthread_create(pthread_t *thread, std::nullptr_t, 49 void *(*start_routine)(void *), void *arg) { 50 *thread = new std::thread(start_routine, arg); 51 } 52 inline void pthread_join(pthread_t thread, std::nullptr_t) { thread->join(); } 53 inline void pthread_mutex_init(pthread_mutex_t *mutex, std::nullptr_t) { 54 *mutex = new std::mutex; 55 } 56 inline void pthread_mutex_lock(pthread_mutex_t *mutex) { (*mutex)->lock(); } 57 inline void pthread_mutex_unlock(pthread_mutex_t *mutex) { (*mutex)->unlock(); } 58 inline void pthread_mutex_destroy(pthread_mutex_t *mutex) { delete *mutex; } 59 inline void pthread_cond_init(pthread_cond_t *cond, std::nullptr_t) { 60 *cond = new std::condition_variable; 61 } 62 inline void pthread_cond_signal(pthread_cond_t *cond) { (*cond)->notify_one(); } 63 inline void pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex) { 64 std::unique_lock<std::mutex> lock(**mutex, std::adopt_lock); 65 (*cond)->wait(lock); 66 // detach lock from mutex so when we leave this conext 67 // the lock is not released 68 lock.release(); 69 } 70 inline void pthread_cond_destroy(pthread_cond_t *cond) { delete *cond; } 71 } // end namespace gemmlowp 72 #endif 73 74 #endif // GEMMLOWP_PROFILING_PTHREAD_EVERYWHERE_H_ 75
