This was an oversight in the original commit adding wait/notify
to atomic<T>.
libstdc++-v3/ChangeLog:
PR libstdc++/102994
* include/bits/atomic_base.h (__atomic_base<_PTp*>::wait()):
Add const qualifier.
* include/std/atomic (atomic<_Tp*>::wait(), atomic_wait()):
Likewise.
* testsuite/29_atomics/atomic/wait_notify/102994.cc:
New test.
For some reason r170217 didn't add compare_exchange_weak to the
__atomic_base<T*> partial specialization, and so weak compare exchange
operations on pointers use compare_exchange_strong instead.
This adds __atomic_base<T*>::compare_exchange_weak and then uses it in
std::atomic<T*>::compare_exchange_weak.
Signed-off-by: Jonathan Wakely <jwakely@redhat.com>
libstdc++-v3/ChangeLog:
* include/bits/atomic_base.h (__atomic_base<P*>::compare_exchange_weak):
Add new functions.
* include/std/atomic (atomic<T*>::compare_exchange_weak): Use
it.
P0418R2 removed some preconditions from std::atomic::compare_exchange_*
but we still enforce them via __glibcxx_assert. This removes those
assertions.
Signed-off-by: Jonathan Wakely <jwakely@redhat.com>
libstdc++-v3/ChangeLog:
PR c++/102177
* include/bits/atomic_base.h (__is_valid_cmpexch_failure_order):
New function to check if a memory order is valid for the failure
case of compare exchange operations.
(__atomic_base<I>::compare_exchange_weak): Simplify assertions
by using __is_valid_cmpexch_failure_order.
(__atomic_base<I>::compare_exchange_strong): Likewise.
(__atomic_base<P*>::compare_exchange_weak): Likewise.
(__atomic_base<P*>::compare_exchange_strong): Likewise.
(__atomic_impl::compare_exchange_weak): Add assertion.
(__atomic_impl::compare_exchange_strong): Likewise.
* include/std/atomic (atomic::compare_exchange_weak): Likewise.
(atomic::compare_exchange_strong): Likewise.
This is a substantial rewrite of the atomic wait/notify (and timed wait
counterparts) implementation.
The previous __platform_wait looped on EINTR however this behavior is
not required by the standard. A new _GLIBCXX_HAVE_PLATFORM_WAIT macro
now controls whether wait/notify are implemented using a platform
specific primitive or with a platform agnostic mutex/condvar. This
patch only supplies a definition for linux futexes. A future update
could add support __ulock_wait/wake on Darwin, for instance.
The members of __waiters were lifted to a new base class. The members
are now arranged such that overall sizeof(__waiter_pool_base) fits in
two cache lines (on platforms with at least 64 byte cache lines). The
definition will also use destructive_interference_size for this if it is
available.
The __waiters type is now specific to untimed waits, and is renamed to
__waiter_pool. Timed waits have a corresponding __timed_waiter_pool
type. Much of the code has been moved from the previous __atomic_wait()
free function to the __waiter_base template and a __waiter derived type
is provided to implement the un-timed wait operations. A similar change
has been made to the timed wait implementation.
The __atomic_spin code has been extended to take a spin policy which is
invoked after the initial busy wait loop. The default policy is to
return from the spin. The timed wait code adds a timed backoff spinning
policy. The code from <thread> which implements this_thread::sleep_for,
sleep_until has been moved to a new <bits/std_thread_sleep.h> header
which allows the thread sleep code to be consumed without pulling in the
whole of <thread>.
The entry points into the wait/notify code have been restructured to
support either -
* Testing the current value of the atomic stored at the given address
and waiting on a notification.
* Applying a predicate to determine if the wait was satisfied.
The entry points were renamed to make it clear that the wait and wake
operations operate on addresses. The first variant takes the expected
value and a function which returns the current value that should be used
in comparison operations, these operations are named with a _v suffix
(e.g. 'value'). All atomic<_Tp> wait/notify operations use the first
variant. Barriers, latches and semaphores use the predicate variant.
This change also centralizes what it means to compare values for the
purposes of atomic<T>::wait rather than scattering through individual
predicates.
This change also centralizes the repetitive code which adjusts for
different user supplied clocks (this should be moved elsewhere
and all such adjustments should use a common implementation).
This change also removes the hashing of the pointer and uses
the pointer value directly for indexing into the waiters table.
libstdc++-v3/ChangeLog:
* include/Makefile.am: Add new <bits/this_thread_sleep.h> header.
* include/Makefile.in: Regenerate.
* include/bits/this_thread_sleep.h: New file.
* include/bits/atomic_base.h: Adjust all calls
to __atomic_wait/__atomic_notify for new call signatures.
* include/bits/atomic_timed_wait.h: Extensive rewrite.
* include/bits/atomic_wait.h: Likewise.
* include/bits/semaphore_base.h: Adjust all calls
to __atomic_wait/__atomic_notify for new call signatures.
* include/std/atomic: Likewise.
* include/std/barrier: Likewise.
* include/std/latch: Likewise.
* include/std/semaphore: Likewise.
* include/std/thread (this_thread::sleep_for)
(this_thread::sleep_until): Move to new header.
* testsuite/29_atomics/atomic/wait_notify/bool.cc: Simplify
test.
* testsuite/29_atomics/atomic/wait_notify/generic.cc: Likewise.
* testsuite/29_atomics/atomic/wait_notify/pointers.cc: Likewise.
* testsuite/29_atomics/atomic_flag/wait_notify/1.cc: Likewise.
* testsuite/29_atomics/atomic_float/wait_notify.cc: Likewise.
* testsuite/29_atomics/atomic_integral/wait_notify.cc: Likewise.
* testsuite/29_atomics/atomic_ref/wait_notify.cc: Likewise.
Adds __cpp_lib_atomic_wait feature test macro which was overlooked in
the initial commit of this feature. Replaces uses of
_GLIBCXX_HAVE_ATOMIC_WAIT.
libstdc++-v3/ChangeLog:
* include/bits/atomic_base.h: Replace usage of
_GLIBCXX_HAVE_ATOMIC_WAIT with __cpp_lib_atomic_wait.
* include/bits/atomic_timed_wait.h: Likewise.
* include/bits/atomic_wait.h: Define __cpp_lib_atomic_wait
feature test macro.
* include/bits/semaphore_base.h: Replace usage of
_GLIBCXX_HAVE_ATOMIC_WAIT with __cpp_lib_atomic_wait.
* include/std/atomic: Likewise.
* include/std/latch: Likewise.
* include/std/semaphore: Likewise.
* include/std/version: Define __cpp_lib_atomic wait
feature test macro and replace usage of
_GLIBCXX_HAVE_ATOMIC_WAIT.
* testsuite/29_atomics/atomic/wait_notify/1.cc: New test.
* testsuite/29_atomics/atomic/wait_notify/2.cc: Likewise.
In order to simplify the preprocessor checks for whether __atomic_wait
is available, this commit does:
-#if defined _GLIBCXX_HAS_GTHREADS || _GLIBCXX_HAVE_LINUX_FUTEX
+#ifdef _GLIBCXX_HAVE_ATOMIC_WAIT
The original was wrong anyway, as it should have used 'defined' to check
_GLIBCXX_HAVE_LINUX_FUTEX (for consistency with how that's used
elsewhere).
The new macro is defined in <bits/atomic_wait.h> when the file is
defines __atomic_wait and related facilities. All other code that
depends on those features can just check the one macro.
libstdc++-v3/ChangeLog:
* include/bits/atomic_wait.h (_GLIBCXX_HAVE_ATOMIC_WAIT):
Define.
* include/bits/atomic_base.h: Check _GLIBCXX_HAVE_ATOMIC_WAIT.
* include/bits/atomic_timed_wait.h: Likewise.
* include/bits/semaphore_base.h: Likewise.
* include/std/atomic: Likewise.
* include/std/latch: Likewise.
* include/std/semaphore: Likewise.
C++20 adds some new preconditions to std::atomic, which weren't
previously checked by our implementation.
* include/std/atomic (atomic): Add static assertions.
* testsuite/29_atomics/atomic/requirements/types_neg.cc: New test.
These macros all correspond to features that are already supported, but
the macro was not defined when the feature was implemented.
* include/bits/ptr_traits.h (__cpp_lib_constexpr_memory): Define to
indicate P1006R1 support.
(__cpp_lib_to_address): Define to indicate P0653R2 support.
* include/bits/range_access.h (__cpp_lib_ssize): Define to indicate
P1227R2 support.
* include/bits/ranges_algo.h (__cpp_lib_shift): Define to indicate
P0769R2 support.
* include/std/atomic (__cpp_lib_atomic_float): Define to indicate
P0020R6 support.
* include/std/memory (__cpp_lib_assume_aligned): Define to indicate
P1007R3 support.
* include/std/memory_resource (__cpp_lib_polymorphic_allocator):
Define to indicate P0339R6 support.
* include/std/string_view (__cpp_lib_starts_ends_with): Define to
indicate P0457R2 support.
* include/std/type_traits (__cpp_lib_is_nothrow_convertible): Define
to indicate P0758R1 support.
(__cpp_lib_remove_cvref): Define to indicate P0550R2 support.
(__cpp_lib_type_identity): Define to indicate P0887R1 support.
* include/std/version (__cpp_lib_atomic_float)
(__cpp_lib_is_nothrow_convertible, __cpp_lib_remove_cvref)
(__cpp_lib_type_identity, __cpp_lib_assume_aligned)
(__cpp_lib_constexpr_memory, __cpp_lib_polymorphic_allocator)
(__cpp_lib_shift, __cpp_lib_ssize, __cpp_lib_starts_ends_with)
(__cpp_lib_to_address): Define.
* testsuite/20_util/to_address/1_neg.cc: Adjust dg-error line number.
This implements the new requirements for C++20 that std::atomic should
initialize the atomic variable in its default constructor.
This patch does not add the deprecated attribute to atomic_init, but
that should be done at some point as it's deprecated in C++20.
The paper also deprecates the ATOMIC_FLAG_INIT macro, although we can't
apply the deprecated attribute to a macro.
PR libstdc++/58605
* include/bits/atomic_base.h (__cpp_lib_atomic_value_initialization):
Define.
(__atomic_flag_base, __atomic_base, __atomic_base<_PTp*>)
(__atomic_float): Add default member initializer for C++20.
* include/std/atomic (atomic): Likewise.
(atomic::atomic()): Remove noexcept-specifier on default constructor.
* include/std/version (__cpp_lib_atomic_value_initialization): Define.
* testsuite/29_atomics/atomic/cons/assign_neg.cc: Adjust dg-error line
number.
* testsuite/29_atomics/atomic/cons/copy_neg.cc: Likewise.
* testsuite/29_atomics/atomic/cons/value_init.cc: New test.
* testsuite/29_atomics/atomic_flag/cons/value_init.cc: New test.
* testsuite/29_atomics/atomic_flag/requirements/trivial.cc: Adjust
expected result for is_trivially_default_constructible.
* testsuite/29_atomics/atomic_float/requirements.cc: Likewise.
* testsuite/29_atomics/atomic_float/value_init.cc: New test.
* testsuite/29_atomics/atomic_integral/cons/assign_neg.cc: Likewise.
* testsuite/29_atomics/atomic_integral/cons/copy_neg.cc: Likewise.
* testsuite/29_atomics/atomic_integral/cons/value_init.cc
* testsuite/29_atomics/atomic_integral/requirements/trivial.cc: Adjust
expected results for is_trivially_default_constructible.
* testsuite/util/testsuite_common_types.h (has_trivial_dtor): Add
new test generator.
This adds the new atomic types from C++2a, as proposed by P0019 and
P0020. To reduce duplication the calls to the compiler's atomic
built-ins are wrapped in new functions in the __atomic_impl namespace.
These functions are currently only used by std::atomic<floating-point>
and std::atomic_ref but could also be used for all other specializations
of std::atomic.
* include/bits/atomic_base.h (__atomic_impl): New namespace for
wrappers around atomic built-ins.
(__atomic_float, __atomic_ref): New class templates for use as base
classes.
* include/std/atomic (atomic<float>, atomic<double>)
(atomic<long double>): New explicit specializations.
(atomic_ref): New class template.
(__cpp_lib_atomic_ref): Define.
* include/std/version (__cpp_lib_atomic_ref): Define.
* testsuite/29_atomics/atomic/60695.cc: Adjust dg-error.
* testsuite/29_atomics/atomic_float/1.cc: New test.
* testsuite/29_atomics/atomic_float/requirements.cc: New test.
* testsuite/29_atomics/atomic_ref/deduction.cc: New test.
* testsuite/29_atomics/atomic_ref/float.cc: New test.
* testsuite/29_atomics/atomic_ref/generic.cc: New test.
* testsuite/29_atomics/atomic_ref/integral.cc: New test.
* testsuite/29_atomics/atomic_ref/pointer.cc: New test.
* testsuite/29_atomics/atomic_ref/requirements.cc: New test.
From-SVN: r273420
The restrictions forbidding arithmetic on atomic pointer types are only
enabled for C++17 and later, retaining the GNU extension for older
standards. The new nested typedefs and changes to prevent scalar
parameters participating in template argument deduction are enabled
unconditionally.
PR libstdc++/69769
PR libstdc++/85886
* include/bits/atomic_base.h (__atomic_base::value_type)
(__atomic_base::difference_type): Add new typedefs.
* include/std/atomic (atomic<bool>::value_type, atomic<T>::value_type)
(atomic<T*>::value_type, atomic<T*>::difference_type): Likewise.
(atomic<T*>::operator++, atomic<T*>::operator--)
(atomic<T*>::operator+=, atomic<T*>::operator-=)
(atomic<T*>::fetch_add, atomic<T*>::fetch_sub): Add static assertion
to enforce C++17 requirement on pointer arithmetic.
(__atomic_val_t, __atomic_diff_t): New alias templates.
(atomic_init, atomic_store_explicit, atomic_exchange_explicit)
(atomic_compare_exchange_weak_explicit)
(atomic_compare_exchange_strong_explicit, atomic_store)
(atomic_exchange, atomic_compare_exchange_weak)
(atomic_compare_exchange_strong): Use __atomic_val_t to make
scalar parameters be non-deduced contexts.
(atomic_fetch_add_explicit, atomic_fetch_sub_explicit)
(atomic_fetch_add, atomic_fetch_sub): Change first parameter to be
atomic instead of __atomic_base, and use __atomic_diff_t for scalar
parameters.
(atomic_fetch_and_explicit, atomic_fetch_or_explicit)
(atomic_fetch_xor_explicit, atomic_fetch_and, atomic_fetch_or)
(atomic_fetch_xor): Use __atomic_val_t for scalar parameters.
(atomic_fetch_add_explicit, atomic_fetch_sub_explicit)
(atomic_fetch_add, atomic_fetch_sub): Remove overloads for atomic
address types.
* testsuite/29_atomics/atomic/60695.cc: Adjust dg-error lineno.
* testsuite/29_atomics/atomic/69769.cc: New test.
* testsuite/29_atomics/atomic/nonmembers.cc: New test.
* testsuite/29_atomics/atomic/operators/pointer_partial_void.cc:
Disable test for C++17 and later.
* testsuite/29_atomics/atomic/requirements/typedefs.cc: New test.
* testsuite/29_atomics/atomic_integral/nonmembers.cc: New test.
* testsuite/29_atomics/atomic_integral/requirements/typedefs.cc: New
test.
From-SVN: r260676
gcc:
2015-09-17 Richard Henderson <rth@redhat.com>
PR libstdc++/65913
* builtins.c (fold_builtin_atomic_always_lock_free): Handle fake
pointers that encode the alignment of the object.
libstdc++-v3:
2015-09-17 Jonathan Wakely <jwakely@redhat.com>
PR libstdc++/65913
* include/bits/atomic_base.h (__atomic_base<_TTp>::is_lock_free(),
__atomic_base<_PTp*>::is_lock_free()): Call the built-in with the
immediate pointer value, not a variable.
* include/std/atomic (atomic<T>::is_lock_free()): Likewise.
* testsuite/29_atomics/atomic/65913.cc: New.
From-SVN: r227878
2015-04-09 Jonathan Wakely <jwakely@redhat.com>
Richard Henderson <rth@redhat.com>
PR libstdc++/65147
* include/bits/atomic_base.h (__atomic_base<_ITp>): Increase
alignment.
* include/std/atomic (atomic): For types with a power of two size set
alignment to at least the size.
* testsuite/29_atomics/atomic/60695.cc: Adjust dg-error line number.
* testsuite/29_atomics/atomic/65147.cc: New.
* testsuite/29_atomics/atomic_integral/65147.cc: New.
Co-Authored-By: Richard Henderson <rth@redhat.com>
From-SVN: r221945
PR libstdc++/62259
PR libstdc++/65147
* include/std/atomic (atomic<T>): Increase alignment for types with
the same size as one of the integral types.
* testsuite/29_atomics/atomic/60695.cc: Adjust dg-error line number.
* testsuite/29_atomics/atomic/62259.cc: New.
From-SVN: r221703
PR libstdc++/60940
* include/bits/atomic_base.h: Remove atomic integral typedefs as
synonyms for __atomic_base<int> etc.
* include/std/atomic: Make atomic_int a synonym for atomic<int> and
likewise for all atomic integral types.
* testsuite/29_atomics/atomic_integral/cons/copy_list.cc: New.
* testsuite/29_atomics/atomic/60695.cc: Adjust dg-error line number.
From-SVN: r219790
2014-10-24 Paolo Carlini <paolo.carlini@oracle.com>
* include/bits/atomic_base.h: Avoid including <stdbool.h>.
* include/std/atomic: When __cplusplus < 201103L skip the rest of
the header.
* testsuite/29_atomics/headers/atomic/std_c++0x_neg.cc: Adjust.
From-SVN: r216667
