I implicitly assumed that programs using pmr::synchronized_pool_resource
would also be using multiple threads, and so the weak symbols in
gthr-posix.h would be resolved by linking to libpthread. If that isn't
true then it crashes when trying to use pthread_key_create.
This commit makes the pool resource check __gthread_active_p() before
using thread-specific data, and just use a single set of memory pools
when there's only a single thread.
PR libstdc++/94936
* src/c++17/memory_resource.cc (synchronized_pool_resource::_TPools):
Add comment about single-threaded behaviour.
(synchronized_pool_resource::_TPools::move_nonempty_chunks()): Hoist
class member access out of loop.
(synchronized_pool_resource::synchronized_pool_resource())
(synchronized_pool_resource::~synchronized_pool_resource())
(synchronized_pool_resource::release()): Check __gthread_active_p
before creating and/or deleting the thread-specific data key.
(synchronized_pool_resource::_M_thread_specific_pools()): Adjust
assertions.
(synchronized_pool_resource::do_allocate(size_t, size_t)): Add fast
path for single-threaded case.
(synchronized_pool_resource::do_deallocate(void*, size_t, size_t)):
Likewise. Return if unable to find a pool that owns the allocation.
* testsuite/20_util/synchronized_pool_resource/allocate_single.cc:
New test.
* testsuite/20_util/synchronized_pool_resource/cons_single.cc: New
test.
* testsuite/20_util/synchronized_pool_resource/release_single.cc: New
test.
Define the thread-safe pool resource, using a shared_mutex to allow
multiple threads to concurrently allocate from thread-specific pools.
Define new weak symbols for the pthread_rwlock_t functions, to avoid
making libstdc++.so depend on libpthread.so
When the necessary Gthread support is absent only define the
feature-test macro to 1, rather than 201603. This is intended to imply
incomplete support, because everything except synchronized_pool_resource
works.
Implement std::pmr::synchronized_pool_resource
* config/abi/pre/gnu.ver: Add new symbols.
* include/std/memory_resource [_GLIBCXX_HAS_GTHREADS]
(__cpp_lib_memory_resource): Define to expected value, 201603.
(synchronized_pool_resource): New class.
[!_GLIBCXX_HAS_GTHREADS] (__cpp_lib_memory_resource): Define to 1.
* include/std/shared_mutex (__glibcxx_rwlock_rdlock)
(__glibcxx_rwlock_tryrdlock, __glibcxx_rwlock_wrlock)
(__glibcxx_rwlock_trywrlock, __glibcxx_rwlock_unlock)
(__glibcxx_rwlock_destroy, __glibcxx_rwlock_init)
(__glibcxx_rwlock_timedrdlock, __glibcxx_rwlock_timedwrlock): Define
weak symbols for POSIX rwlock functions.
(__shared_mutex_pthread): Use weak symbols.
* include/std/version (__cpp_lib_memory_resource): Define.
* src/c++17/memory_resource.cc [_GLIBCXX_HAS_GTHREADS]
(synchronized_pool_resource::_TPools): New class.
(destroy_TPools): New function for pthread_key_create destructor.
(synchronized_pool_resource::synchronized_pool_resource)
(synchronized_pool_resource::~synchronized_pool_resource)
(synchronized_pool_resource::release)
(synchronized_pool_resource::do_allocate)
(synchronized_pool_resource::do_deallocate): Define public members.
(synchronized_pool_resource::_M_thread_specific_pools)
(synchronized_pool_resource::_M_alloc_tpools)
(synchronized_pool_resource::_M_alloc_shared_tpools): Define private
members.
* testsuite/20_util/synchronized_pool_resource/allocate.cc: New test.
* testsuite/20_util/synchronized_pool_resource/cons.cc: New test.
* testsuite/20_util/synchronized_pool_resource/is_equal.cc: New test.
* testsuite/20_util/synchronized_pool_resource/multithreaded.cc: New
test.
* testsuite/20_util/synchronized_pool_resource/release.cc: New test.
* testsuite/performance/20_util/memory_resource/pools.cc: Add
multithreaded tests using pmr::synchronized_pool_resource.
From-SVN: r266242
