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ldionneldionne
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[libc++] Split a few utilities out of __threading_support
This change is the basis for a further refactoring where I'm going to split up the various implementations we have in __threading_support to make that code easier to understand. Note that I had to make __convert_to_timespec a template to break circular dependencies. Concretely, we never seem to use it with anything other than ::timespec, but I am wary of hardcoding that assumption as part of this change, since I suspect there's a reason for going through these hoops in the first place. Differential Revision: https://reviews.llvm.org/D116944
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13 files changed

+144
-53
lines changed

13 files changed

+144
-53
lines changed

‎libcxx/include/CMakeLists.txt‎

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@@ -105,6 +105,7 @@ set(files
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__charconv/from_chars_result.h
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__charconv/to_chars_result.h
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__chrono/calendar.h
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__chrono/convert_to_timespec.h
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__chrono/duration.h
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__chrono/file_clock.h
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__chrono/high_resolution_clock.h
@@ -367,6 +368,7 @@ set(files
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__support/xlocale/__posix_l_fallback.h
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__support/xlocale/__strtonum_fallback.h
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__thread/poll_with_backoff.h
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__thread/timed_backoff_policy.h
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__threading_support
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__tree
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__tuple

‎libcxx/include/__chrono/convert_to_timespec.h‎

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// -*- C++ -*-
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//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef _LIBCPP___CHRONO_CONVERT_TO_TIMESPEC_H
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#define _LIBCPP___CHRONO_CONVERT_TO_TIMESPEC_H
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#include <__chrono/duration.h>
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#include <__config>
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#include <limits>
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#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
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#pragma GCC system_header
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#endif
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_LIBCPP_PUSH_MACROS
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#include <__undef_macros>
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_LIBCPP_BEGIN_NAMESPACE_STD
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// Convert a nanoseconds duration to the given TimeSpec type, which must have
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// the same properties as std::timespec.
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template <class _TimeSpec>
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_LIBCPP_HIDE_FROM_ABI inline
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_TimeSpec __convert_to_timespec(const chrono::nanoseconds& __ns)
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{
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using namespace chrono;
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seconds __s = duration_cast<seconds>(__ns);
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_TimeSpec __ts;
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typedef decltype(__ts.tv_sec) __ts_sec;
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const __ts_sec __ts_sec_max = numeric_limits<__ts_sec>::max();
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if (__s.count() < __ts_sec_max)
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{
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__ts.tv_sec = static_cast<__ts_sec>(__s.count());
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__ts.tv_nsec = static_cast<decltype(__ts.tv_nsec)>((__ns - __s).count());
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}
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else
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{
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__ts.tv_sec = __ts_sec_max;
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__ts.tv_nsec = 999999999; // (10^9 - 1)
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}
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return __ts;
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}
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_LIBCPP_END_NAMESPACE_STD
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_LIBCPP_POP_MACROS
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#endif // _LIBCPP___CHRONO_CONVERT_TO_TIMESPEC_H

‎libcxx/include/__thread/timed_backoff_policy.h‎

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// -*- C++ -*-
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//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef _LIBCPP___THREAD_TIMED_BACKOFF_POLICY_H
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#define _LIBCPP___THREAD_TIMED_BACKOFF_POLICY_H
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#include <__config>
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#ifndef _LIBCPP_HAS_NO_THREADS
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#include <__threading_support>
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#include <chrono>
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#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
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#pragma GCC system_header
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#endif
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_LIBCPP_BEGIN_NAMESPACE_STD
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struct __libcpp_timed_backoff_policy {
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_LIBCPP_INLINE_VISIBILITY
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bool operator()(chrono::nanoseconds __elapsed) const
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{
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if(__elapsed > chrono::milliseconds(128))
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__libcpp_thread_sleep_for(chrono::milliseconds(8));
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else if(__elapsed > chrono::microseconds(64))
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__libcpp_thread_sleep_for(__elapsed / 2);
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else if(__elapsed > chrono::microseconds(4))
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__libcpp_thread_yield();
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else
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{} // poll
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return false;
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}
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};
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_LIBCPP_END_NAMESPACE_STD
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#endif // _LIBCPP_HAS_NO_THREADS
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#endif // _LIBCPP___THREAD_TIMED_BACKOFF_POLICY_H

‎libcxx/include/__threading_support‎

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@@ -54,9 +54,6 @@
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typedef ::timespec __libcpp_timespec_t;
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#endif // !defined(_LIBCPP_HAS_NO_THREADS)
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_LIBCPP_PUSH_MACROS
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#include <__undef_macros>
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_LIBCPP_BEGIN_NAMESPACE_STD
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#if !defined(_LIBCPP_HAS_NO_THREADS)
@@ -252,53 +249,9 @@ int __libcpp_tls_set(__libcpp_tls_key __key, void *__p);
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#endif // !defined(_LIBCPP_HAS_THREAD_API_EXTERNAL)
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struct __libcpp_timed_backoff_policy {
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_LIBCPP_INLINE_VISIBILITY
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bool operator()(chrono::nanoseconds __elapsed) const
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{
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if(__elapsed > chrono::milliseconds(128))
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__libcpp_thread_sleep_for(chrono::milliseconds(8));
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else if(__elapsed > chrono::microseconds(64))
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__libcpp_thread_sleep_for(__elapsed / 2);
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else if(__elapsed > chrono::microseconds(4))
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__libcpp_thread_yield();
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else
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{} // poll
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return false;
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}
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};
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#if (!defined(_LIBCPP_HAS_THREAD_LIBRARY_EXTERNAL) || \
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defined(_LIBCPP_BUILDING_THREAD_LIBRARY_EXTERNAL))
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namespace __thread_detail {
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_LIBCPP_HIDE_FROM_ABI inline
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__libcpp_timespec_t __convert_to_timespec(const chrono::nanoseconds& __ns)
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{
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using namespace chrono;
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seconds __s = duration_cast<seconds>(__ns);
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__libcpp_timespec_t __ts;
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typedef decltype(__ts.tv_sec) __ts_sec;
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const __ts_sec __ts_sec_max = numeric_limits<__ts_sec>::max();
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if (__s.count() < __ts_sec_max)
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{
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__ts.tv_sec = static_cast<__ts_sec>(__s.count());
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__ts.tv_nsec = static_cast<decltype(__ts.tv_nsec)>((__ns - __s).count());
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}
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else
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{
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__ts.tv_sec = __ts_sec_max;
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__ts.tv_nsec = 999999999; // (10^9 - 1)
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}
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return __ts;
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}
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} // namespace __thread_detail
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#if defined(_LIBCPP_HAS_THREAD_API_PTHREAD)
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_LIBCPP_HIDE_FROM_ABI inline
@@ -479,7 +432,7 @@ void __libcpp_thread_yield()
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_LIBCPP_HIDE_FROM_ABI inline
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void __libcpp_thread_sleep_for(const chrono::nanoseconds& __ns)
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{
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__libcpp_timespec_t __ts = __thread_detail::__convert_to_timespec(__ns);
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__libcpp_timespec_t __ts = _VSTD::__convert_to_timespec<__libcpp_timespec_t>(__ns);
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while (nanosleep(&__ts, &__ts) == -1 && errno == EINTR);
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}
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@@ -664,7 +617,7 @@ void __libcpp_thread_yield()
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_LIBCPP_HIDE_FROM_ABI inline
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void __libcpp_thread_sleep_for(const chrono::nanoseconds& __ns)
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{
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__libcpp_timespec_t __ts = __thread_detail::__convert_to_timespec(__ns);
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__libcpp_timespec_t __ts = _VSTD::__convert_to_timespec<__libcpp_timespec_t>(__ns);
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thrd_sleep(&__ts, nullptr);
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}
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@@ -776,6 +729,4 @@ get_id() _NOEXCEPT
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_LIBCPP_END_NAMESPACE_STD
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_LIBCPP_POP_MACROS
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#endif // _LIBCPP_THREADING_SUPPORT

‎libcxx/include/atomic‎

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@@ -521,6 +521,7 @@ template <class T>
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#include <__availability>
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#include <__config>
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#include <__thread/poll_with_backoff.h>
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#include <__thread/timed_backoff_policy.h>
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#include <cstddef>
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#include <cstdint>
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#include <cstring>

‎libcxx/include/barrier‎

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#include <__availability>
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#include <__config>
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#include <__thread/timed_backoff_policy.h>
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#include <atomic>
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#ifndef _LIBCPP_HAS_NO_TREE_BARRIER
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# include <memory>

‎libcxx/include/chrono‎

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*/
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#include <__chrono/calendar.h>
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#include <__chrono/convert_to_timespec.h>
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#include <__chrono/duration.h>
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#include <__chrono/file_clock.h>
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#include <__chrono/high_resolution_clock.h>

‎libcxx/include/module.modulemap‎

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@@ -367,6 +367,7 @@ module std [system] {
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module __chrono {
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module calendar { private header "__chrono/calendar.h" }
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module convert_to_timespec { private header "__chrono/convert_to_timespec.h" }
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module duration { private header "__chrono/duration.h" }
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module file_clock { private header "__chrono/file_clock.h" }
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module high_resolution_clock { private header "__chrono/high_resolution_clock.h" }
@@ -902,7 +903,8 @@ module std [system] {
902903
export *
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904905
module __thread {
905-
module poll_with_backoff { private header "__thread/poll_with_backoff.h" }
906+
module poll_with_backoff { private header "__thread/poll_with_backoff.h" }
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module timed_backoff_policy { private header "__thread/timed_backoff_policy.h" }
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}
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}
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module tuple {

‎libcxx/include/semaphore‎

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@@ -47,6 +47,7 @@ using binary_semaphore = counting_semaphore<1>;
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#include <__availability>
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#include <__config>
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#include <__thread/timed_backoff_policy.h>
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#include <__threading_support>
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#include <atomic>
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#include <version>

‎libcxx/include/thread‎

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@@ -87,6 +87,7 @@ void sleep_for(const chrono::duration<Rep, Period>& rel_time);
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#include <__functional_base>
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#include <__mutex_base>
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#include <__thread/poll_with_backoff.h>
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#include <__thread/timed_backoff_policy.h>
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#include <__threading_support>
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#include <__utility/forward.h>
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#include <chrono>

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