diff options
| -rw-r--r-- | libstdc++-v3/src/c++11/futex.cc | 36 | ||||
| -rw-r--r-- | libstdc++-v3/testsuite/30_threads/future/members/wait_until_overflow.cc | 48 |
2 files changed, 70 insertions, 14 deletions
diff --git a/libstdc++-v3/src/c++11/futex.cc b/libstdc++-v3/src/c++11/futex.cc index c2b2d32e8c4..15959cebee5 100644 --- a/libstdc++-v3/src/c++11/futex.cc +++ b/libstdc++-v3/src/c++11/futex.cc @@ -51,6 +51,8 @@ namespace std _GLIBCXX_VISIBILITY(default) { _GLIBCXX_BEGIN_NAMESPACE_VERSION + using __gnu_cxx::__int_traits; + namespace { std::atomic<bool> futex_clock_realtime_unavailable; @@ -74,10 +76,10 @@ namespace auto rel_s = abs_s.count() - now_s; // Avoid overflows - if (rel_s > __gnu_cxx::__int_traits<time_t>::__max) - rel_s = __gnu_cxx::__int_traits<time_t>::__max; - else if (rel_s < __gnu_cxx::__int_traits<time_t>::__min) - rel_s = __gnu_cxx::__int_traits<time_t>::__min; + if (rel_s > __int_traits<time_t>::__max) [[unlikely]] + rel_s = __int_traits<time_t>::__max; + else if (rel_s < __int_traits<time_t>::__min) [[unlikely]] + rel_s = __int_traits<time_t>::__min; // Convert the absolute timeout value to a relative timeout rt.tv_sec = rel_s; @@ -111,14 +113,17 @@ namespace { if (!futex_clock_realtime_unavailable.load(std::memory_order_relaxed)) { - struct timespec rt; - rt.tv_sec = __s.count(); - rt.tv_nsec = __ns.count(); - // futex sets errno=EINVAL for absolute timeouts before the epoch. - if (__builtin_expect(rt.tv_sec < 0, false)) + if (__s.count() < 0) return false; + struct timespec rt; + if (__s.count() > __int_traits<time_t>::__max) [[unlikely]] + rt.tv_sec = __int_traits<time_t>::__max; + else + rt.tv_sec = __s.count(); + rt.tv_nsec = __ns.count(); + if (syscall (SYS_futex, __addr, futex_wait_bitset_op | futex_clock_realtime_flag, __val, &rt, nullptr, futex_bitset_match_any) == -1) @@ -184,14 +189,17 @@ namespace { if (!futex_clock_monotonic_unavailable.load(std::memory_order_relaxed)) { - struct timespec rt; - rt.tv_sec = __s.count(); - rt.tv_nsec = __ns.count(); - // futex sets errno=EINVAL for absolute timeouts before the epoch. - if (__builtin_expect(rt.tv_sec < 0, false)) + if (__s.count() < 0) [[unlikely]] return false; + struct timespec rt; + if (__s.count() > __int_traits<time_t>::__max) [[unlikely]] + rt.tv_sec = __int_traits<time_t>::__max; + else + rt.tv_sec = __s.count(); + rt.tv_nsec = __ns.count(); + if (syscall (SYS_futex, __addr, futex_wait_bitset_op | futex_clock_monotonic_flag, __val, &rt, nullptr, futex_bitset_match_any) == -1) diff --git a/libstdc++-v3/testsuite/30_threads/future/members/wait_until_overflow.cc b/libstdc++-v3/testsuite/30_threads/future/members/wait_until_overflow.cc new file mode 100644 index 00000000000..8d6a5148ce3 --- /dev/null +++ b/libstdc++-v3/testsuite/30_threads/future/members/wait_until_overflow.cc @@ -0,0 +1,48 @@ +// { dg-do run } +// { dg-additional-options "-pthread" { target pthread } } +// { dg-require-effective-target c++11 } +// { dg-require-gthreads "" } + +// Copyright (C) 2020 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 +// <http://www.gnu.org/licenses/>. + + +#include <future> +#include <chrono> +#include <climits> +#include <testsuite_hooks.h> + +namespace chrono = std::chrono; + +void test01() +{ + std::future<void> fut = std::async(std::launch::async, [] { + std::this_thread::sleep_for(chrono::seconds(4)); + }); + + // A time in the distant future, but which overflows 32-bit time_t: + auto then = chrono::system_clock::now() + chrono::seconds(UINT_MAX + 2LL); + auto status = fut.wait_until(then); + // The wait_until call should have waited for the result to be ready. + // If converting the time_point to time_t overflows, it will timeout. + VERIFY(status == std::future_status::ready); +} + +int main() +{ + test01(); +} |