head	1.1;
branch	1.1.1;
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	netbsd-11-0-RC5:1.1.1.1
	netbsd-11-0-RC4:1.1.1.1
	netbsd-11-0-RC3:1.1.1.1
	netbsd-11-0-RC2:1.1.1.1
	netbsd-11-0-RC1:1.1.1.1
	gcc-14-3-0:1.1.1.2
	perseant-exfatfs-base-20250801:1.1.1.1
	netbsd-11:1.1.1.1.0.4
	netbsd-11-base:1.1.1.1
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	gcc-12-4-0:1.1.1.1
	perseant-exfatfs:1.1.1.1.0.2
	perseant-exfatfs-base:1.1.1.1
	gcc-12-3-0:1.1.1.1
	FSF:1.1.1;
locks; strict;
comment	@ * @;


1.1
date	2023.07.30.05.21.20;	author mrg;	state Exp;
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1.1.1.1
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1.1.1.2
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desc
@@


1.1
log
@Initial revision
@
text
@// -*- C++ -*- header.

// Copyright (C) 2020-2022 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.

// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.

// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
// <http://www.gnu.org/licenses/>.

/** @@file bits/atomic_timed_wait.h
 *  This is an internal header file, included by other library headers.
 *  Do not attempt to use it directly. @@headername{atomic}
 */

#ifndef _GLIBCXX_ATOMIC_TIMED_WAIT_H
#define _GLIBCXX_ATOMIC_TIMED_WAIT_H 1

#pragma GCC system_header

#include <bits/atomic_wait.h>

#if __cpp_lib_atomic_wait
#include <bits/functional_hash.h>
#include <bits/this_thread_sleep.h>
#include <bits/chrono.h>

#ifdef _GLIBCXX_HAVE_LINUX_FUTEX
#include <sys/time.h>
#endif

namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION

  namespace __detail
  {
    using __wait_clock_t = chrono::steady_clock;

    template<typename _Clock, typename _Dur>
      __wait_clock_t::time_point
      __to_wait_clock(const chrono::time_point<_Clock, _Dur>& __atime) noexcept
      {
	const typename _Clock::time_point __c_entry = _Clock::now();
	const __wait_clock_t::time_point __w_entry = __wait_clock_t::now();
	const auto __delta = __atime - __c_entry;
	using __w_dur = typename __wait_clock_t::duration;
	return __w_entry + chrono::ceil<__w_dur>(__delta);
      }

    template<typename _Dur>
      __wait_clock_t::time_point
      __to_wait_clock(const chrono::time_point<__wait_clock_t,
					       _Dur>& __atime) noexcept
      {
	using __w_dur = typename __wait_clock_t::duration;
	return chrono::ceil<__w_dur>(__atime);
      }

#ifdef _GLIBCXX_HAVE_LINUX_FUTEX
#define _GLIBCXX_HAVE_PLATFORM_TIMED_WAIT
    // returns true if wait ended before timeout
    template<typename _Dur>
      bool
      __platform_wait_until_impl(const __platform_wait_t* __addr,
				 __platform_wait_t __old,
				 const chrono::time_point<__wait_clock_t, _Dur>&
				      __atime) noexcept
      {
	auto __s = chrono::time_point_cast<chrono::seconds>(__atime);
	auto __ns = chrono::duration_cast<chrono::nanoseconds>(__atime - __s);

	struct timespec __rt =
	{
	  static_cast<std::time_t>(__s.time_since_epoch().count()),
	  static_cast<long>(__ns.count())
	};

	auto __e = syscall (SYS_futex, __addr,
			    static_cast<int>(__futex_wait_flags::
						__wait_bitset_private),
			    __old, &__rt, nullptr,
			    static_cast<int>(__futex_wait_flags::
						__bitset_match_any));

	if (__e)
	  {
	    if (errno == ETIMEDOUT)
	      return false;
	    if (errno != EINTR && errno != EAGAIN)
	      __throw_system_error(errno);
	  }
	return true;
      }

    // returns true if wait ended before timeout
    template<typename _Clock, typename _Dur>
      bool
      __platform_wait_until(const __platform_wait_t* __addr, __platform_wait_t __old,
			    const chrono::time_point<_Clock, _Dur>& __atime)
      {
	if constexpr (is_same_v<__wait_clock_t, _Clock>)
	  {
	    return __platform_wait_until_impl(__addr, __old, __atime);
	  }
	else
	  {
	    if (!__platform_wait_until_impl(__addr, __old,
					    __to_wait_clock(__atime)))
	      {
		// We got a timeout when measured against __clock_t but
		// we need to check against the caller-supplied clock
		// to tell whether we should return a timeout.
		if (_Clock::now() < __atime)
		  return true;
	      }
	    return false;
	  }
      }
#else
// define _GLIBCXX_HAVE_PLATFORM_TIMED_WAIT and implement __platform_wait_until()
// if there is a more efficient primitive supported by the platform
// (e.g. __ulock_wait())which is better than pthread_cond_clockwait
#endif // ! PLATFORM_TIMED_WAIT

#ifdef _GLIBCXX_HAS_GTHREADS
    // Returns true if wait ended before timeout.
    // _Clock must be either steady_clock or system_clock.
    template<typename _Clock, typename _Dur>
      bool
      __cond_wait_until_impl(__condvar& __cv, mutex& __mx,
			     const chrono::time_point<_Clock, _Dur>& __atime)
      {
	static_assert(std::__is_one_of<_Clock, chrono::steady_clock,
					       chrono::system_clock>::value);

	auto __s = chrono::time_point_cast<chrono::seconds>(__atime);
	auto __ns = chrono::duration_cast<chrono::nanoseconds>(__atime - __s);

	__gthread_time_t __ts =
	  {
	    static_cast<std::time_t>(__s.time_since_epoch().count()),
	    static_cast<long>(__ns.count())
	  };

#ifdef _GLIBCXX_USE_PTHREAD_COND_CLOCKWAIT
	if constexpr (is_same_v<chrono::steady_clock, _Clock>)
	  __cv.wait_until(__mx, CLOCK_MONOTONIC, __ts);
	else
#endif
	  __cv.wait_until(__mx, __ts);
	return _Clock::now() < __atime;
      }

    // returns true if wait ended before timeout
    template<typename _Clock, typename _Dur>
      bool
      __cond_wait_until(__condvar& __cv, mutex& __mx,
	  const chrono::time_point<_Clock, _Dur>& __atime)
      {
#ifdef _GLIBCXX_USE_PTHREAD_COND_CLOCKWAIT
	if constexpr (is_same_v<_Clock, chrono::steady_clock>)
	  return __detail::__cond_wait_until_impl(__cv, __mx, __atime);
	else
#endif
	if constexpr (is_same_v<_Clock, chrono::system_clock>)
	  return __detail::__cond_wait_until_impl(__cv, __mx, __atime);
	else
	  {
	    if (__cond_wait_until_impl(__cv, __mx,
				       __to_wait_clock(__atime)))
	      {
		// We got a timeout when measured against __clock_t but
		// we need to check against the caller-supplied clock
		// to tell whether we should return a timeout.
		if (_Clock::now() < __atime)
		  return true;
	      }
	    return false;
	  }
      }
#endif // _GLIBCXX_HAS_GTHREADS

    struct __timed_waiter_pool : __waiter_pool_base
    {
      // returns true if wait ended before timeout
      template<typename _Clock, typename _Dur>
	bool
	_M_do_wait_until(__platform_wait_t* __addr, __platform_wait_t __old,
			 const chrono::time_point<_Clock, _Dur>& __atime)
	{
#ifdef _GLIBCXX_HAVE_PLATFORM_TIMED_WAIT
	  return __platform_wait_until(__addr, __old, __atime);
#else
	  __platform_wait_t __val;
	  __atomic_load(__addr, &__val, __ATOMIC_RELAXED);
	  if (__val == __old)
	    {
	      lock_guard<mutex> __l(_M_mtx);
	      return __cond_wait_until(_M_cv, _M_mtx, __atime);
	    }
	  else
	    return true;
#endif // _GLIBCXX_HAVE_PLATFORM_TIMED_WAIT
	}
    };

    struct __timed_backoff_spin_policy
    {
      __wait_clock_t::time_point _M_deadline;
      __wait_clock_t::time_point _M_t0;

      template<typename _Clock, typename _Dur>
	__timed_backoff_spin_policy(chrono::time_point<_Clock, _Dur>
				      __deadline = _Clock::time_point::max(),
				    chrono::time_point<_Clock, _Dur>
				      __t0 = _Clock::now()) noexcept
	  : _M_deadline(__to_wait_clock(__deadline))
	  , _M_t0(__to_wait_clock(__t0))
	{ }

      bool
      operator()() const noexcept
      {
	using namespace literals::chrono_literals;
	auto __now = __wait_clock_t::now();
	if (_M_deadline <= __now)
	  return false;

	// FIXME: this_thread::sleep_for not available #ifdef _GLIBCXX_NO_SLEEP

	auto __elapsed = __now - _M_t0;
	if (__elapsed > 128ms)
	  {
	    this_thread::sleep_for(64ms);
	  }
	else if (__elapsed > 64us)
	  {
	    this_thread::sleep_for(__elapsed / 2);
	  }
	else if (__elapsed > 4us)
	  {
	    __thread_yield();
	  }
	else
	  return false;
	return true;
      }
    };

    template<typename _EntersWait>
      struct __timed_waiter : __waiter_base<__timed_waiter_pool>
      {
	using __base_type = __waiter_base<__timed_waiter_pool>;

	template<typename _Tp>
	  __timed_waiter(const _Tp* __addr) noexcept
	  : __base_type(__addr)
	{
	  if constexpr (_EntersWait::value)
	    _M_w._M_enter_wait();
	}

	~__timed_waiter()
	{
	  if constexpr (_EntersWait::value)
	    _M_w._M_leave_wait();
	}

	// returns true if wait ended before timeout
	template<typename _Tp, typename _ValFn,
		 typename _Clock, typename _Dur>
	  bool
	  _M_do_wait_until_v(_Tp __old, _ValFn __vfn,
			     const chrono::time_point<_Clock, _Dur>&
								__atime) noexcept
	  {
	    __platform_wait_t __val;
	    if (_M_do_spin(__old, std::move(__vfn), __val,
			   __timed_backoff_spin_policy(__atime)))
	      return true;
	    return __base_type::_M_w._M_do_wait_until(__base_type::_M_addr, __val, __atime);
	  }

	// returns true if wait ended before timeout
	template<typename _Pred,
		 typename _Clock, typename _Dur>
	  bool
	  _M_do_wait_until(_Pred __pred, __platform_wait_t __val,
			  const chrono::time_point<_Clock, _Dur>&
							      __atime) noexcept
	  {
	    for (auto __now = _Clock::now(); __now < __atime;
		  __now = _Clock::now())
	      {
		if (__base_type::_M_w._M_do_wait_until(
		      __base_type::_M_addr, __val, __atime)
		    && __pred())
		  return true;

		if (__base_type::_M_do_spin(__pred, __val,
			       __timed_backoff_spin_policy(__atime, __now)))
		  return true;
	      }
	    return false;
	  }

	// returns true if wait ended before timeout
	template<typename _Pred,
		 typename _Clock, typename _Dur>
	  bool
	  _M_do_wait_until(_Pred __pred,
			   const chrono::time_point<_Clock, _Dur>&
								__atime) noexcept
	  {
	    __platform_wait_t __val;
	    if (__base_type::_M_do_spin(__pred, __val,
					__timed_backoff_spin_policy(__atime)))
	      return true;
	    return _M_do_wait_until(__pred, __val, __atime);
	  }

	template<typename _Tp, typename _ValFn,
		 typename _Rep, typename _Period>
	  bool
	  _M_do_wait_for_v(_Tp __old, _ValFn __vfn,
			   const chrono::duration<_Rep, _Period>&
								__rtime) noexcept
	  {
	    __platform_wait_t __val;
	    if (_M_do_spin_v(__old, std::move(__vfn), __val))
	      return true;

	    if (!__rtime.count())
	      return false; // no rtime supplied, and spin did not acquire

	    auto __reltime = chrono::ceil<__wait_clock_t::duration>(__rtime);

	    return __base_type::_M_w._M_do_wait_until(
					  __base_type::_M_addr,
					  __val,
					  chrono::steady_clock::now() + __reltime);
	  }

	template<typename _Pred,
		 typename _Rep, typename _Period>
	  bool
	  _M_do_wait_for(_Pred __pred,
			 const chrono::duration<_Rep, _Period>& __rtime) noexcept
	  {
	    __platform_wait_t __val;
	    if (__base_type::_M_do_spin(__pred, __val))
	      return true;

	    if (!__rtime.count())
	      return false; // no rtime supplied, and spin did not acquire

	    auto __reltime = chrono::ceil<__wait_clock_t::duration>(__rtime);

	    return _M_do_wait_until(__pred, __val,
				    chrono::steady_clock::now() + __reltime);
	  }
      };

    using __enters_timed_wait = __timed_waiter<std::true_type>;
    using __bare_timed_wait = __timed_waiter<std::false_type>;
  } // namespace __detail

  // returns true if wait ended before timeout
  template<typename _Tp, typename _ValFn,
	   typename _Clock, typename _Dur>
    bool
    __atomic_wait_address_until_v(const _Tp* __addr, _Tp&& __old, _ValFn&& __vfn,
			const chrono::time_point<_Clock, _Dur>&
			    __atime) noexcept
    {
      __detail::__enters_timed_wait __w{__addr};
      return __w._M_do_wait_until_v(__old, __vfn, __atime);
    }

  template<typename _Tp, typename _Pred,
	   typename _Clock, typename _Dur>
    bool
    __atomic_wait_address_until(const _Tp* __addr, _Pred __pred,
				const chrono::time_point<_Clock, _Dur>&
							      __atime) noexcept
    {
      __detail::__enters_timed_wait __w{__addr};
      return __w._M_do_wait_until(__pred, __atime);
    }

  template<typename _Pred,
	   typename _Clock, typename _Dur>
    bool
    __atomic_wait_address_until_bare(const __detail::__platform_wait_t* __addr,
				_Pred __pred,
				const chrono::time_point<_Clock, _Dur>&
							      __atime) noexcept
    {
      __detail::__bare_timed_wait __w{__addr};
      return __w._M_do_wait_until(__pred, __atime);
    }

  template<typename _Tp, typename _ValFn,
	   typename _Rep, typename _Period>
    bool
    __atomic_wait_address_for_v(const _Tp* __addr, _Tp&& __old, _ValFn&& __vfn,
		      const chrono::duration<_Rep, _Period>& __rtime) noexcept
    {
      __detail::__enters_timed_wait __w{__addr};
      return __w._M_do_wait_for_v(__old, __vfn, __rtime);
    }

  template<typename _Tp, typename _Pred,
	   typename _Rep, typename _Period>
    bool
    __atomic_wait_address_for(const _Tp* __addr, _Pred __pred,
		      const chrono::duration<_Rep, _Period>& __rtime) noexcept
    {

      __detail::__enters_timed_wait __w{__addr};
      return __w._M_do_wait_for(__pred, __rtime);
    }

  template<typename _Pred,
	   typename _Rep, typename _Period>
    bool
    __atomic_wait_address_for_bare(const __detail::__platform_wait_t* __addr,
			_Pred __pred,
			const chrono::duration<_Rep, _Period>& __rtime) noexcept
    {
      __detail::__bare_timed_wait __w{__addr};
      return __w._M_do_wait_for(__pred, __rtime);
    }
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace std
#endif // __cpp_lib_atomic_wait
#endif // _GLIBCXX_ATOMIC_TIMED_WAIT_H
@


1.1.1.1
log
@initial import of GCC 12.3.0.

major changes in GCC 11 included:

- The default mode for C++ is now -std=gnu++17 instead of -std=gnu++14.
- When building GCC itself, the host compiler must now support C++11,
  rather than C++98.
- Some short options of the gcov tool have been renamed: -i to -j and
  -j to -H.
- ThreadSanitizer improvements.
- Introduce Hardware-assisted AddressSanitizer support.
- For targets that produce DWARF debugging information GCC now defaults
  to DWARF version 5. This can produce up to 25% more compact debug
  information compared to earlier versions.
- Many optimisations.
- The existing malloc attribute has been extended so that it can be
  used to identify allocator/deallocator API pairs. A pair of new
  -Wmismatched-dealloc and -Wmismatched-new-delete warnings are added.
- Other new warnings:
  -Wsizeof-array-div, enabled by -Wall, warns about divisions of two
    sizeof operators when the first one is applied to an array and the
    divisor does not equal the size of the array element.
  -Wstringop-overread, enabled by default, warns about calls to string
    functions reading past the end of the arrays passed to them as
    arguments.
  -Wtsan, enabled by default, warns about unsupported features in
    ThreadSanitizer (currently std::atomic_thread_fence).
- Enchanced warnings:
  -Wfree-nonheap-object detects many more instances of calls to
    deallocation functions with pointers not returned from a dynamic
    memory allocation function.
  -Wmaybe-uninitialized diagnoses passing pointers or references to
    uninitialized memory to functions taking const-qualified arguments.
  -Wuninitialized detects reads from uninitialized dynamically
    allocated memory.
  -Warray-parameter warns about functions with inconsistent array forms.
  -Wvla-parameter warns about functions with inconsistent VLA forms.
- Several new features from the upcoming C2X revision of the ISO C
  standard are supported with -std=c2x and -std=gnu2x.
- Several C++20 features have been implemented.
- The C++ front end has experimental support for some of the upcoming
  C++23 draft.
- Several new C++ warnings.
- Enhanced Arm, AArch64, x86, and RISC-V CPU support.
- The implementation of how program state is tracked within
  -fanalyzer has been completely rewritten with many enhancements.

see https://gcc.gnu.org/gcc-11/changes.html for a full list.

major changes in GCC 12 include:

- An ABI incompatibility between C and C++ when passing or returning
  by value certain aggregates containing zero width bit-fields has
  been discovered on various targets. x86-64, ARM and AArch64
  will always ignore them (so there is a C ABI incompatibility
  between GCC 11 and earlier with GCC 12 or later), PowerPC64 ELFv2
  always take them into account (so there is a C++ ABI
  incompatibility, GCC 4.4 and earlier compatible with GCC 12 or
  later, incompatible with GCC 4.5 through GCC 11). RISC-V has
  changed the handling of these already starting with GCC 10. As
  the ABI requires, MIPS takes them into account handling function
  return values so there is a C++ ABI incompatibility with GCC 4.5
  through 11.
- STABS: Support for emitting the STABS debugging format is
  deprecated and will be removed in the next release. All ports now
  default to emit DWARF (version 2 or later) debugging info or are
  obsoleted.
- Vectorization is enabled at -O2 which is now equivalent to the
  original -O2 -ftree-vectorize -fvect-cost-model=very-cheap.
- GCC now supports the ShadowCallStack sanitizer.
- Support for __builtin_shufflevector compatible with the clang
  language extension was added.
- Support for attribute unavailable was added.
- Support for __builtin_dynamic_object_size compatible with the
  clang language extension was added.
- New warnings:
  -Wbidi-chars warns about potentially misleading UTF-8
    bidirectional control characters.
  -Warray-compare warns about comparisons between two operands of
    array type.
- Some new features from the upcoming C2X revision of the ISO C
  standard are supported with -std=c2x and -std=gnu2x.
- Several C++23 features have been implemented.
- Many C++ enhancements across warnings and -f options.

see https://gcc.gnu.org/gcc-12/changes.html for a full list.
@
text
@@


1.1.1.2
log
@initial import of GCC 14.3.0.

major changes in GCC 13:
- improved sanitizer
- zstd debug info compression
- LTO improvements
- SARIF based diagnostic support
- new warnings: -Wxor-used-as-pow, -Wenum-int-mismatch, -Wself-move,
  -Wdangling-reference
- many new -Wanalyzer* specific warnings
- enhanced warnings: -Wpessimizing-move, -Wredundant-move
- new attributes to mark file descriptors, c++23 "assume"
- several C23 features added
- several C++23 features added
- many new features for Arm, x86, RISC-V

major changes in GCC 14:
- more strict C99 or newer support
- ia64* marked deprecated (but seemingly still in GCC 15.)
- several new hardening features
- support for "hardbool", which can have user supplied values of true/false
- explicit support for stack scrubbing upon function exit
- better auto-vectorisation support
- added clang-compatible __has_feature and __has_extension
- more C23, including -std=c23
- several C++26 features added
- better diagnostics in C++ templates
- new warnings: -Wnrvo, Welaborated-enum-base
- many new features for Arm, x86, RISC-V
- possible ABI breaking change for SPARC64 and small structures with arrays
  of floats.
@
text
@d3 1
a3 1
// Copyright (C) 2020-2024 Free Software Foundation, Inc.
d37 1
a37 1
#if __glibcxx_atomic_wait
@