This series complete Tom's work to refactor the C++20 atomic wait/notify
code, and includes several follow-up patches from me. The goal is to
move the core implementation pieces into libstdc++.so instead of
defining everything inline in the headers. This is a necessary step for
stabilizing C++20 support for GCC 16.
This fixes:
- PR 98749 - No precondition checks in <semaphore>, <latch> and <barrier>
- PR 99572 - std::counting_semaphore coalescing wakes
- PR 104928 - std::counting_semaphore on Linux can sleep forever
- PR 110854 - constructor of std::counting_semaphore is not constexpr
- PR 118395 - Constructor of std::barrier is not constexpr
- PR 99995 - should not include <unistd.h> in c++20 mode
Not fixed:
- PR 115955 - atomic<T>::wait _S_for uses a poor hash function
This can be fixed at leisure once the definition moves into the shared
library and isn't defined inline in headers.
- PR 118402 - std::barrier doesn't use futex directly
See the bugzilla PR for discussion.
All tests pass on x86_64-linux and sparc-solaris and power-aix. I'm not
expecting further review of this series, but I'm posting it one more
time before pushing because I want to see the Linaro CI results.
Jonathan Wakely (14):
libstdc++: Whitespace fixes in atomic wait/notify code
libstdc++: Various fixes for atomic wait/notify code
libstdc++: Fix race condition in new atomic notify code
libstdc++: Fix time_point conversion in atomic timed waits
libstdc++: Simplify futex wrapper functions for atomic wait/notify
libstdc++: Remove reinterpret_cast uses in atomic wait/notify
libstdc++: Rename __atomic_compare to __atomic_eq
libstdc++: Rename __waiter_pool_impl to __waitable_state
libstdc++: Move atomic wait/notify entry points into the library
libstdc++: Optimise std::latch::arrive_and_wait
libstdc++: Fix std::barrier for constant initialization [PR118395]
libstdc++: Create new base class of std::barrier<C> for non-dependent
code
libstdc++: Rewrite std::counting_semaphore base class [PR118494]
libstdc++: Define __wait_result_type for atomic waiting
Thomas Rodgers (2):
libstdc++: Atomic wait/notify ABI stabilization
libstdc++: Pass __wait_args to internal API by const pointer
libstdc++-v3/acinclude.m4 | 37 --
libstdc++-v3/config.h.in | 4 -
libstdc++-v3/config/abi/pre/gnu.ver | 11 +
libstdc++-v3/configure | 60 +--
libstdc++-v3/include/bits/atomic_timed_wait.h | 452 ++++------------
libstdc++-v3/include/bits/atomic_wait.h | 495 ++++++------------
libstdc++-v3/include/bits/semaphore_base.h | 235 +++------
libstdc++-v3/include/bits/version.def | 2 +-
libstdc++-v3/include/bits/version.h | 2 +-
libstdc++-v3/include/std/barrier | 199 ++++---
libstdc++-v3/include/std/latch | 26 +-
libstdc++-v3/include/std/semaphore | 32 +-
libstdc++-v3/src/c++20/Makefile.am | 2 +-
libstdc++-v3/src/c++20/Makefile.in | 4 +-
libstdc++-v3/src/c++20/atomic.cc | 485 +++++++++++++++++
.../17_intro/headers/c++1998/49745.cc | 2 -
.../29_atomics/atomic/wait_notify/100334.cc | 7 +-
.../29_atomics/atomic_integral/wait_notify.cc | 8 +-
.../testsuite/30_threads/barrier/cons.cc | 6 +
.../testsuite/30_threads/barrier/lwg3898.cc | 45 ++
.../testsuite/30_threads/semaphore/100806.cc | 2 +-
.../testsuite/30_threads/semaphore/cons.cc | 7 +
.../semaphore/platform_try_acquire_for.cc | 9 -
.../30_threads/semaphore/try_acquire_posix.cc | 153 ------
libstdc++-v3/testsuite/util/testsuite_abi.cc | 1 +
25 files changed, 1056 insertions(+), 1230 deletions(-)
create mode 100644 libstdc++-v3/src/c++20/atomic.cc
create mode 100644 libstdc++-v3/testsuite/30_threads/barrier/cons.cc
create mode 100644 libstdc++-v3/testsuite/30_threads/barrier/lwg3898.cc
create mode 100644 libstdc++-v3/testsuite/30_threads/semaphore/cons.cc
delete mode 100644
libstdc++-v3/testsuite/30_threads/semaphore/platform_try_acquire_for.cc
delete mode 100644
libstdc++-v3/testsuite/30_threads/semaphore/try_acquire_posix.cc
--
2.49.0
