mirror of
https://github.com/jart/cosmopolitan.git
synced 2025-01-31 11:37:35 +00:00
112 lines
4.1 KiB
C++
112 lines
4.1 KiB
C++
//===----------------------------------------------------------------------===//
|
|
//
|
|
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
|
|
// See https://llvm.org/LICENSE.txt for license information.
|
|
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#ifndef _LIBCPP___ATOMIC_ATOMIC_SYNC_H
|
|
#define _LIBCPP___ATOMIC_ATOMIC_SYNC_H
|
|
|
|
#include <__atomic/contention_t.h>
|
|
#include <__atomic/cxx_atomic_impl.h>
|
|
#include <__atomic/memory_order.h>
|
|
#include <__availability>
|
|
#include <__chrono/duration.h>
|
|
#include <__config>
|
|
#include <__memory/addressof.h>
|
|
#include <__thread/poll_with_backoff.h>
|
|
#include <__threading_support>
|
|
#include <__type_traits/decay.h>
|
|
#include <cstring>
|
|
|
|
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
|
|
# pragma GCC system_header
|
|
#endif
|
|
|
|
_LIBCPP_BEGIN_NAMESPACE_STD
|
|
|
|
#ifndef _LIBCPP_HAS_NO_THREADS
|
|
|
|
_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI void __cxx_atomic_notify_one(void const volatile*);
|
|
_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI void __cxx_atomic_notify_all(void const volatile*);
|
|
_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI __cxx_contention_t __libcpp_atomic_monitor(void const volatile*);
|
|
_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI void __libcpp_atomic_wait(void const volatile*, __cxx_contention_t);
|
|
|
|
_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI void __cxx_atomic_notify_one(__cxx_atomic_contention_t const volatile*);
|
|
_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI void __cxx_atomic_notify_all(__cxx_atomic_contention_t const volatile*);
|
|
_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI __cxx_contention_t __libcpp_atomic_monitor(__cxx_atomic_contention_t const volatile*);
|
|
_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI void __libcpp_atomic_wait(__cxx_atomic_contention_t const volatile*, __cxx_contention_t);
|
|
|
|
template <class _Atp, class _Fn>
|
|
struct __libcpp_atomic_wait_backoff_impl {
|
|
_Atp* __a;
|
|
_Fn __test_fn;
|
|
_LIBCPP_AVAILABILITY_SYNC
|
|
_LIBCPP_HIDE_FROM_ABI bool operator()(chrono::nanoseconds __elapsed) const
|
|
{
|
|
if(__elapsed > chrono::microseconds(64))
|
|
{
|
|
auto const __monitor = std::__libcpp_atomic_monitor(__a);
|
|
if(__test_fn())
|
|
return true;
|
|
std::__libcpp_atomic_wait(__a, __monitor);
|
|
}
|
|
else if(__elapsed > chrono::microseconds(4))
|
|
__libcpp_thread_yield();
|
|
else
|
|
{} // poll
|
|
return false;
|
|
}
|
|
};
|
|
|
|
template <class _Atp, class _Fn>
|
|
_LIBCPP_AVAILABILITY_SYNC
|
|
_LIBCPP_HIDE_FROM_ABI bool __cxx_atomic_wait(_Atp* __a, _Fn && __test_fn)
|
|
{
|
|
__libcpp_atomic_wait_backoff_impl<_Atp, __decay_t<_Fn> > __backoff_fn = {__a, __test_fn};
|
|
return std::__libcpp_thread_poll_with_backoff(__test_fn, __backoff_fn);
|
|
}
|
|
|
|
#else // _LIBCPP_HAS_NO_THREADS
|
|
|
|
template <class _Tp>
|
|
_LIBCPP_HIDE_FROM_ABI void __cxx_atomic_notify_all(__cxx_atomic_impl<_Tp> const volatile*) { }
|
|
template <class _Tp>
|
|
_LIBCPP_HIDE_FROM_ABI void __cxx_atomic_notify_one(__cxx_atomic_impl<_Tp> const volatile*) { }
|
|
template <class _Atp, class _Fn>
|
|
_LIBCPP_HIDE_FROM_ABI bool __cxx_atomic_wait(_Atp*, _Fn && __test_fn)
|
|
{
|
|
return std::__libcpp_thread_poll_with_backoff(__test_fn, __spinning_backoff_policy());
|
|
}
|
|
|
|
#endif // _LIBCPP_HAS_NO_THREADS
|
|
|
|
template <typename _Tp> _LIBCPP_HIDE_FROM_ABI
|
|
bool __cxx_nonatomic_compare_equal(_Tp const& __lhs, _Tp const& __rhs) {
|
|
return std::memcmp(std::addressof(__lhs), std::addressof(__rhs), sizeof(_Tp)) == 0;
|
|
}
|
|
|
|
template <class _Atp, class _Tp>
|
|
struct __cxx_atomic_wait_test_fn_impl {
|
|
_Atp* __a;
|
|
_Tp __val;
|
|
memory_order __order;
|
|
_LIBCPP_HIDE_FROM_ABI bool operator()() const
|
|
{
|
|
return !std::__cxx_nonatomic_compare_equal(std::__cxx_atomic_load(__a, __order), __val);
|
|
}
|
|
};
|
|
|
|
template <class _Atp, class _Tp>
|
|
_LIBCPP_AVAILABILITY_SYNC
|
|
_LIBCPP_HIDE_FROM_ABI bool __cxx_atomic_wait(_Atp* __a, _Tp const __val, memory_order __order)
|
|
{
|
|
__cxx_atomic_wait_test_fn_impl<_Atp, _Tp> __test_fn = {__a, __val, __order};
|
|
return std::__cxx_atomic_wait(__a, __test_fn);
|
|
}
|
|
|
|
_LIBCPP_END_NAMESPACE_STD
|
|
|
|
#endif // _LIBCPP___ATOMIC_ATOMIC_SYNC_H
|