This backport contains 4 patch from gcc main stream tree. The commit id of these patchs list as following in the order of time. 0001-PR-libstdc++-68519-use-native-duration-to-avoid-rounding.patch 83fd5e73b3c16296e0d7ba54f6c547e01c7eae7b 0001-Use-steady_clock-to-implement-condition_variable-wait_for.patch 9e68aa3cc52956ea99bb726c3c29ce0581b9f7e7 0001-Use-steady_clock-to-implement-condition_variable-wait_for.patch 29b26763f5552129996bfc732cfa2087d7c9657c 0001-PR-libstdc++-41861-Add-full-steady_clock-support-to.patch ad4d1d21ad5c515ba90355d13b14cbb74262edd2 diff -Nurp a/libstdc++-v3/acinclude.m4 b/libstdc++-v3/acinclude.m4 --- a/libstdc++-v3/acinclude.m4 2021-04-25 03:41:20.232000000 +0800 +++ b/libstdc++-v3/acinclude.m4 2021-04-25 03:42:23.352000000 +0800 @@ -4092,6 +4092,37 @@ AC_DEFUN([GLIBCXX_CHECK_PTHREADS_NUM_PRO ]) dnl +dnl Check whether pthread_cond_clockwait is available in for std::condition_variable to use, +dnl and define _GLIBCXX_USE_PTHREAD_COND_CLOCKWAIT. +dnl +AC_DEFUN([GLIBCXX_CHECK_PTHREAD_COND_CLOCKWAIT], [ + + AC_LANG_SAVE + AC_LANG_CPLUSPLUS + ac_save_CXXFLAGS="$CXXFLAGS" + CXXFLAGS="$CXXFLAGS -fno-exceptions" + ac_save_LIBS="$LIBS" + LIBS="$LIBS -lpthread" + + AC_MSG_CHECKING([for pthread_cond_clockwait]) + AC_CACHE_VAL(glibcxx_cv_PTHREAD_COND_CLOCKWAIT, [ + GCC_TRY_COMPILE_OR_LINK( + [#include ], + [pthread_mutex_t mutex; pthread_cond_t cond; struct timespec ts; int n = pthread_cond_clockwait(&cond, &mutex, 0, &ts);], + [glibcxx_cv_PTHREAD_COND_CLOCKWAIT=yes], + [glibcxx_cv_PTHREAD_COND_CLOCKWAIT=no]) + ]) + if test $glibcxx_cv_PTHREAD_COND_CLOCKWAIT = yes; then + AC_DEFINE(_GLIBCXX_USE_PTHREAD_COND_CLOCKWAIT, 1, [Define if pthread_cond_clockwait is available in .]) + fi + AC_MSG_RESULT($glibcxx_cv_PTHREAD_COND_CLOCKWAIT) + + CXXFLAGS="$ac_save_CXXFLAGS" + LIBS="$ac_save_LIBS" + AC_LANG_RESTORE +]) + +dnl dnl Check whether sysctl is available in , and define _GLIBCXX_USE_SYSCTL_HW_NCPU. dnl AC_DEFUN([GLIBCXX_CHECK_SYSCTL_HW_NCPU], [ diff -Nurp a/libstdc++-v3/config.h.in b/libstdc++-v3/config.h.in --- a/libstdc++-v3/config.h.in 2021-04-25 03:41:20.220000000 +0800 +++ b/libstdc++-v3/config.h.in 2021-04-25 03:42:23.352000000 +0800 @@ -939,6 +939,9 @@ /* Define if pthreads_num_processors_np is available in . */ #undef _GLIBCXX_USE_PTHREADS_NUM_PROCESSORS_NP +/* Define if pthread_cond_clockwait is available in . */ +#undef _GLIBCXX_USE_PTHREAD_COND_CLOCKWAIT + /* Define if POSIX read/write locks are available in . */ #undef _GLIBCXX_USE_PTHREAD_RWLOCK_T diff -Nurp a/libstdc++-v3/configure b/libstdc++-v3/configure --- a/libstdc++-v3/configure 2021-04-25 03:41:20.220000000 +0800 +++ b/libstdc++-v3/configure 2021-04-25 03:42:23.364000000 +0800 @@ -21264,6 +21264,89 @@ ac_compiler_gnu=$ac_cv_c_compiler_gnu +# For pthread_cond_clockwait + + + + ac_ext=cpp +ac_cpp='$CXXCPP $CPPFLAGS' +ac_compile='$CXX -c $CXXFLAGS $CPPFLAGS conftest.$ac_ext >&5' +ac_link='$CXX -o conftest$ac_exeext $CXXFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5' +ac_compiler_gnu=$ac_cv_cxx_compiler_gnu + + ac_save_CXXFLAGS="$CXXFLAGS" + CXXFLAGS="$CXXFLAGS -fno-exceptions" + ac_save_LIBS="$LIBS" + LIBS="$LIBS -lpthread" + + { $as_echo "$as_me:${as_lineno-$LINENO}: checking for pthread_cond_clockwait" >&5 +$as_echo_n "checking for pthread_cond_clockwait... " >&6; } + if ${glibcxx_cv_PTHREAD_COND_CLOCKWAIT+:} false; then : + $as_echo_n "(cached) " >&6 +else + + if test x$gcc_no_link = xyes; then + cat confdefs.h - <<_ACEOF >conftest.$ac_ext +/* end confdefs.h. */ +#include +int +main () +{ +pthread_mutex_t mutex; pthread_cond_t cond; struct timespec ts; int n = pthread_cond_clockwait(&cond, &mutex, 0, &ts); + ; + return 0; +} +_ACEOF +if ac_fn_cxx_try_compile "$LINENO"; then : + glibcxx_cv_PTHREAD_COND_CLOCKWAIT=yes +else + glibcxx_cv_PTHREAD_COND_CLOCKWAIT=no +fi +rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext +else + if test x$gcc_no_link = xyes; then + as_fn_error $? "Link tests are not allowed after GCC_NO_EXECUTABLES." "$LINENO" 5 +fi +cat confdefs.h - <<_ACEOF >conftest.$ac_ext +/* end confdefs.h. */ +#include +int +main () +{ +pthread_mutex_t mutex; pthread_cond_t cond; struct timespec ts; int n = pthread_cond_clockwait(&cond, &mutex, 0, &ts); + ; + return 0; +} +_ACEOF +if ac_fn_cxx_try_link "$LINENO"; then : + glibcxx_cv_PTHREAD_COND_CLOCKWAIT=yes +else + glibcxx_cv_PTHREAD_COND_CLOCKWAIT=no +fi +rm -f core conftest.err conftest.$ac_objext \ + conftest$ac_exeext conftest.$ac_ext +fi + +fi + + if test $glibcxx_cv_PTHREAD_COND_CLOCKWAIT = yes; then + +$as_echo "#define _GLIBCXX_USE_PTHREAD_COND_CLOCKWAIT 1" >>confdefs.h + + fi + { $as_echo "$as_me:${as_lineno-$LINENO}: result: $glibcxx_cv_PTHREAD_COND_CLOCKWAIT" >&5 +$as_echo "$glibcxx_cv_PTHREAD_COND_CLOCKWAIT" >&6; } + + CXXFLAGS="$ac_save_CXXFLAGS" + LIBS="$ac_save_LIBS" + ac_ext=c +ac_cpp='$CPP $CPPFLAGS' +ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5' +ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5' +ac_compiler_gnu=$ac_cv_c_compiler_gnu + + + ac_fn_c_check_header_mongrel "$LINENO" "locale.h" "ac_cv_header_locale_h" "$ac_includes_default" if test "x$ac_cv_header_locale_h" = x""yes; then : diff -Nurp a/libstdc++-v3/configure.ac b/libstdc++-v3/configure.ac --- a/libstdc++-v3/configure.ac 2021-04-25 03:41:20.220000000 +0800 +++ b/libstdc++-v3/configure.ac 2021-04-25 03:42:23.364000000 +0800 @@ -220,6 +220,9 @@ GLIBCXX_ENABLE_LIBSTDCXX_TIME # Check for tmpnam which is obsolescent in POSIX.1-2008 GLIBCXX_CHECK_TMPNAM +# For pthread_cond_clockwait +GLIBCXX_CHECK_PTHREAD_COND_CLOCKWAIT + AC_LC_MESSAGES # For hardware_concurrency diff -Nurp a/libstdc++-v3/include/std/condition_variable b/libstdc++-v3/include/std/condition_variable --- a/libstdc++-v3/include/std/condition_variable 2021-04-25 03:41:19.916000000 +0800 +++ b/libstdc++-v3/include/std/condition_variable 2021-04-25 03:42:23.364000000 +0800 @@ -64,7 +64,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION /// condition_variable class condition_variable { - typedef chrono::system_clock __clock_t; + using steady_clock = chrono::steady_clock; + using system_clock = chrono::system_clock; +#ifdef _GLIBCXX_USE_PTHREAD_COND_CLOCKWAIT + using __clock_t = steady_clock; +#else + using __clock_t = system_clock; +#endif typedef __gthread_cond_t __native_type; #ifdef __GTHREAD_COND_INIT @@ -99,10 +105,18 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION wait(__lock); } +#ifdef _GLIBCXX_USE_PTHREAD_COND_CLOCKWAIT + template + cv_status + wait_until(unique_lock& __lock, + const chrono::time_point& __atime) + { return __wait_until_impl(__lock, __atime); } +#endif + template cv_status wait_until(unique_lock& __lock, - const chrono::time_point<__clock_t, _Duration>& __atime) + const chrono::time_point& __atime) { return __wait_until_impl(__lock, __atime); } template @@ -110,7 +124,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION wait_until(unique_lock& __lock, const chrono::time_point<_Clock, _Duration>& __atime) { - // DR 887 - Sync unknown clock to known clock. const typename _Clock::time_point __c_entry = _Clock::now(); const __clock_t::time_point __s_entry = __clock_t::now(); const auto __delta = __atime - __c_entry; @@ -135,24 +148,61 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION cv_status wait_for(unique_lock& __lock, const chrono::duration<_Rep, _Period>& __rtime) - { return wait_until(__lock, __clock_t::now() + __rtime); } + { + using __dur = typename steady_clock::duration; + auto __reltime = chrono::duration_cast<__dur>(__rtime); + if (__reltime < __rtime) + ++__reltime; + return wait_until(__lock, steady_clock::now() + __reltime); + } template bool wait_for(unique_lock& __lock, const chrono::duration<_Rep, _Period>& __rtime, _Predicate __p) - { return wait_until(__lock, __clock_t::now() + __rtime, std::move(__p)); } + { + using __dur = typename steady_clock::duration; + auto __reltime = chrono::duration_cast<__dur>(__rtime); + if (__reltime < __rtime) + ++__reltime; + return wait_until(__lock, steady_clock::now() + __reltime, + std::move(__p)); + } native_handle_type native_handle() { return &_M_cond; } private: +#ifdef _GLIBCXX_USE_PTHREAD_COND_CLOCKWAIT + template + cv_status + __wait_until_impl(unique_lock& __lock, + const chrono::time_point& __atime) + { + auto __s = chrono::time_point_cast(__atime); + auto __ns = chrono::duration_cast(__atime - __s); + + __gthread_time_t __ts = + { + static_cast(__s.time_since_epoch().count()), + static_cast(__ns.count()) + }; + + pthread_cond_clockwait(&_M_cond, __lock.mutex()->native_handle(), + CLOCK_MONOTONIC, + &__ts); + + return (steady_clock::now() < __atime + ? cv_status::no_timeout : cv_status::timeout); + } +#endif + template cv_status __wait_until_impl(unique_lock& __lock, - const chrono::time_point<__clock_t, _Dur>& __atime) + const chrono::time_point& __atime) { auto __s = chrono::time_point_cast(__atime); auto __ns = chrono::duration_cast(__atime - __s); @@ -166,7 +216,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION __gthread_cond_timedwait(&_M_cond, __lock.mutex()->native_handle(), &__ts); - return (__clock_t::now() < __atime + return (system_clock::now() < __atime ? cv_status::no_timeout : cv_status::timeout); } }; @@ -186,7 +236,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION // Like above, but mutex is not required to have try_lock. class condition_variable_any { - typedef chrono::system_clock __clock_t; +#ifdef _GLIBCXX_USE_PTHREAD_COND_CLOCKWAIT + using __clock_t = chrono::steady_clock; +#else + using __clock_t = chrono::system_clock; +#endif condition_variable _M_cond; shared_ptr _M_mutex; diff -Nurp a/libstdc++-v3/testsuite/30_threads/condition_variable/members/68519.cc b/libstdc++-v3/testsuite/30_threads/condition_variable/members/68519.cc --- a/libstdc++-v3/testsuite/30_threads/condition_variable/members/68519.cc 1970-01-01 08:00:00.000000000 +0800 +++ b/libstdc++-v3/testsuite/30_threads/condition_variable/members/68519.cc 2021-04-25 03:41:43.008000000 +0800 @@ -0,0 +1,51 @@ +// Copyright (C) 2017 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. + +// You should have received a copy of the GNU General Public License along +// with this library; see the file COPYING3. If not see +// . + +// { dg-do run } +// { dg-options "-pthread" } +// { dg-require-effective-target c++11 } +// { dg-require-effective-target pthread } +// { dg-require-cstdint "" } +// { dg-require-gthreads "" } + +#include +#include + +// PR libstdc++/68519 + +bool val = false; +std::mutex mx; +std::condition_variable cv; + +void +test01() +{ + for (int i = 0; i < 3; ++i) + { + std::unique_lock l(mx); + auto start = std::chrono::system_clock::now(); + cv.wait_for(l, std::chrono::duration(1), [] { return val; }); + auto t = std::chrono::system_clock::now(); + VERIFY( (t - start) >= std::chrono::seconds(1) ); + } +} + +int +main() +{ + test01(); +}