diff options
Diffstat (limited to 'libcxx/include')
| -rw-r--r-- | libcxx/include/__threading_support | 71 | ||||
| -rw-r--r-- | libcxx/include/semaphore | 90 | ||||
| -rw-r--r-- | libcxx/include/string | 2 |
3 files changed, 20 insertions, 143 deletions
diff --git a/libcxx/include/__threading_support b/libcxx/include/__threading_support index 4d867167c2b1..2242a6908529 100644 --- a/libcxx/include/__threading_support +++ b/libcxx/include/__threading_support @@ -29,16 +29,9 @@ # include <__external_threading> #elif !defined(_LIBCPP_HAS_NO_THREADS) -#if defined(__APPLE__) || defined(__MVS__) -# define _LIBCPP_NO_NATIVE_SEMAPHORES -#endif - #if defined(_LIBCPP_HAS_THREAD_API_PTHREAD) # include <pthread.h> # include <sched.h> -# ifndef _LIBCPP_NO_NATIVE_SEMAPHORES -# include <semaphore.h> -# endif #elif defined(_LIBCPP_HAS_THREAD_API_C11) # include <threads.h> #endif @@ -78,12 +71,6 @@ typedef pthread_mutex_t __libcpp_recursive_mutex_t; typedef pthread_cond_t __libcpp_condvar_t; #define _LIBCPP_CONDVAR_INITIALIZER PTHREAD_COND_INITIALIZER -#ifndef _LIBCPP_NO_NATIVE_SEMAPHORES -// Semaphore -typedef sem_t __libcpp_semaphore_t; -# define _LIBCPP_SEMAPHORE_MAX SEM_VALUE_MAX -#endif - // Execute once typedef pthread_once_t __libcpp_exec_once_flag; #define _LIBCPP_EXEC_ONCE_INITIALIZER PTHREAD_ONCE_INIT @@ -149,12 +136,6 @@ typedef void* __libcpp_recursive_mutex_t[5]; typedef void* __libcpp_condvar_t; #define _LIBCPP_CONDVAR_INITIALIZER 0 -// Semaphore -typedef void* __libcpp_semaphore_t; -#if defined(_LIBCPP_HAS_THREAD_API_WIN32) -# define _LIBCPP_SEMAPHORE_MAX (::std::numeric_limits<long>::max()) -#endif - // Execute Once typedef void* __libcpp_exec_once_flag; #define _LIBCPP_EXEC_ONCE_INITIALIZER 0 @@ -219,26 +200,6 @@ int __libcpp_condvar_timedwait(__libcpp_condvar_t *__cv, __libcpp_mutex_t *__m, _LIBCPP_THREAD_ABI_VISIBILITY int __libcpp_condvar_destroy(__libcpp_condvar_t* __cv); -#ifndef _LIBCPP_NO_NATIVE_SEMAPHORES - -// Semaphore -_LIBCPP_THREAD_ABI_VISIBILITY -bool __libcpp_semaphore_init(__libcpp_semaphore_t* __sem, int __init); - -_LIBCPP_THREAD_ABI_VISIBILITY -bool __libcpp_semaphore_destroy(__libcpp_semaphore_t* __sem); - -_LIBCPP_THREAD_ABI_VISIBILITY -bool __libcpp_semaphore_post(__libcpp_semaphore_t* __sem); - -_LIBCPP_THREAD_ABI_VISIBILITY -bool __libcpp_semaphore_wait(__libcpp_semaphore_t* __sem); - -_LIBCPP_THREAD_ABI_VISIBILITY -bool __libcpp_semaphore_wait_timed(__libcpp_semaphore_t* __sem, chrono::nanoseconds const& __ns); - -#endif // _LIBCPP_NO_NATIVE_SEMAPHORES - // Execute once _LIBCPP_THREAD_ABI_VISIBILITY int __libcpp_execute_once(__libcpp_exec_once_flag *flag, @@ -452,38 +413,6 @@ int __libcpp_condvar_destroy(__libcpp_condvar_t *__cv) return pthread_cond_destroy(__cv); } -#ifndef _LIBCPP_NO_NATIVE_SEMAPHORES - -// Semaphore -bool __libcpp_semaphore_init(__libcpp_semaphore_t* __sem, int __init) -{ - return sem_init(__sem, 0, __init) == 0; -} - -bool __libcpp_semaphore_destroy(__libcpp_semaphore_t* __sem) -{ - return sem_destroy(__sem) == 0; -} - -bool __libcpp_semaphore_post(__libcpp_semaphore_t* __sem) -{ - return sem_post(__sem) == 0; -} - -bool __libcpp_semaphore_wait(__libcpp_semaphore_t* __sem) -{ - return sem_wait(__sem) == 0; -} - -bool __libcpp_semaphore_wait_timed(__libcpp_semaphore_t* __sem, chrono::nanoseconds const& __ns) -{ - auto const __abs_time = chrono::system_clock::now().time_since_epoch() + __ns; - __libcpp_timespec_t __ts = __thread_detail::__convert_to_timespec(__abs_time); - return sem_timedwait(__sem, &__ts) == 0; -} - -#endif //_LIBCPP_NO_NATIVE_SEMAPHORES - // Execute once int __libcpp_execute_once(__libcpp_exec_once_flag *flag, void (*init_routine)()) { diff --git a/libcxx/include/semaphore b/libcxx/include/semaphore index 906f62e0f07a..db03fb967ed1 100644 --- a/libcxx/include/semaphore +++ b/libcxx/include/semaphore @@ -67,10 +67,7 @@ _LIBCPP_BEGIN_NAMESPACE_STD /* -__atomic_semaphore_base is the general-case implementation, to be used for -user-requested least-max values that exceed the OS implementation support -(incl. when the OS has no support of its own) and for binary semaphores. - +__atomic_semaphore_base is the general-case implementation. It is a typical Dijkstra semaphore algorithm over atomics, wait and notify functions. It avoids contention against users' own use of those facilities. @@ -82,7 +79,7 @@ class __atomic_semaphore_base public: _LIBCPP_INLINE_VISIBILITY - __atomic_semaphore_base(ptrdiff_t __count) : __a(__count) + constexpr explicit __atomic_semaphore_base(ptrdiff_t __count) : __a(__count) { } _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY @@ -108,81 +105,30 @@ public: _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY bool try_acquire_for(chrono::duration<Rep, Period> const& __rel_time) { - auto const __test_fn = [this]() -> bool { - auto __old = __a.load(memory_order_acquire); - while(1) { - if (__old == 0) - return false; - if(__a.compare_exchange_strong(__old, __old - 1, memory_order_acquire, memory_order_relaxed)) - return true; - } - }; + if (__rel_time == chrono::duration<Rep, Period>::zero()) + return try_acquire(); + auto const __test_fn = [this]() { return try_acquire(); }; return __libcpp_thread_poll_with_backoff(__test_fn, __libcpp_timed_backoff_policy(), __rel_time); } -}; - -#ifndef _LIBCPP_NO_NATIVE_SEMAPHORES - -/* - -__platform_semaphore_base a simple wrapper for the OS semaphore type. That -is, every call is routed to the OS in the most direct manner possible. - -*/ - -class __platform_semaphore_base -{ - __libcpp_semaphore_t __semaphore; - -public: - _LIBCPP_INLINE_VISIBILITY - __platform_semaphore_base(ptrdiff_t __count) : - __semaphore() - { - __libcpp_semaphore_init(&__semaphore, __count); - } - _LIBCPP_INLINE_VISIBILITY - ~__platform_semaphore_base() { - __libcpp_semaphore_destroy(&__semaphore); - } - _LIBCPP_INLINE_VISIBILITY - void release(ptrdiff_t __update) - { - for(; __update; --__update) - __libcpp_semaphore_post(&__semaphore); - } - _LIBCPP_INLINE_VISIBILITY - void acquire() - { - __libcpp_semaphore_wait(&__semaphore); - } - _LIBCPP_INLINE_VISIBILITY - bool try_acquire_for(chrono::nanoseconds __rel_time) + _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY + bool try_acquire() { - return __libcpp_semaphore_wait_timed(&__semaphore, __rel_time); + auto __old = __a.load(memory_order_acquire); + while (true) { + if (__old == 0) + return false; + if (__a.compare_exchange_strong(__old, __old - 1, memory_order_acquire, memory_order_relaxed)) + return true; + } } }; -template<ptrdiff_t __least_max_value> -using __semaphore_base = - typename conditional<(__least_max_value > 1 && __least_max_value <= _LIBCPP_SEMAPHORE_MAX), - __platform_semaphore_base, - __atomic_semaphore_base>::type; - -#else - -template<ptrdiff_t __least_max_value> -using __semaphore_base = - __atomic_semaphore_base; - #define _LIBCPP_SEMAPHORE_MAX (numeric_limits<ptrdiff_t>::max()) -#endif //_LIBCPP_NO_NATIVE_SEMAPHORES - template<ptrdiff_t __least_max_value = _LIBCPP_SEMAPHORE_MAX> class counting_semaphore { - __semaphore_base<__least_max_value> __semaphore; + __atomic_semaphore_base __semaphore; public: static constexpr ptrdiff_t max() noexcept { @@ -190,7 +136,7 @@ public: } _LIBCPP_INLINE_VISIBILITY - counting_semaphore(ptrdiff_t __count = 0) : __semaphore(__count) { } + constexpr explicit counting_semaphore(ptrdiff_t __count) : __semaphore(__count) { } ~counting_semaphore() = default; counting_semaphore(const counting_semaphore&) = delete; @@ -215,14 +161,14 @@ public: _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY bool try_acquire() { - return try_acquire_for(chrono::nanoseconds::zero()); + return __semaphore.try_acquire(); } template <class Clock, class Duration> _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY bool try_acquire_until(chrono::time_point<Clock, Duration> const& __abs_time) { auto const current = Clock::now(); - if(current >= __abs_time) + if (current >= __abs_time) return try_acquire(); else return try_acquire_for(__abs_time - current); diff --git a/libcxx/include/string b/libcxx/include/string index 4159ea580345..23dd43792fc6 100644 --- a/libcxx/include/string +++ b/libcxx/include/string @@ -3345,6 +3345,7 @@ basic_string<_CharT, _Traits, _Allocator>::reserve(size_type __requested_capacit } template <class _CharT, class _Traits, class _Allocator> +inline void basic_string<_CharT, _Traits, _Allocator>::shrink_to_fit() _NOEXCEPT { @@ -3355,6 +3356,7 @@ basic_string<_CharT, _Traits, _Allocator>::shrink_to_fit() _NOEXCEPT } template <class _CharT, class _Traits, class _Allocator> +inline void basic_string<_CharT, _Traits, _Allocator>::__shrink_or_extend(size_type __target_capacity) { |