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_broadcast(pthread_cond_t *cond) { |
64 | (*cond)->notify_all(); |
65 | } |
66 | inline void pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex) { |
67 | std::unique_lock<std::mutex> lock(**mutex, std::adopt_lock); |
68 | (*cond)->wait(lock); |
69 | // detach lock from mutex so when we leave this conext |
70 | // the lock is not released |
71 | lock.release(); |
72 | } |
73 | inline void pthread_cond_destroy(pthread_cond_t *cond) { delete *cond; } |
74 | } // end namespace gemmlowp |
75 | #endif |
76 | |
77 | #endif // GEMMLOWP_PROFILING_PTHREAD_EVERYWHERE_H_ |
78 | |