2016-01-04 15:30:50 +01:00
|
|
|
/* Copyright (C) 2012-2016 Free Software Foundation, Inc.
|
2012-05-01 17:48:28 +02:00
|
|
|
Contributed by Richard Henderson <rth@redhat.com>.
|
|
|
|
|
|
|
|
|
|
This file is part of the GNU Atomic Library (libatomic).
|
|
|
|
|
|
|
|
|
|
Libatomic 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 of the License, or
|
|
|
|
|
(at your option) any later version.
|
|
|
|
|
|
|
|
|
|
Libatomic 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.
|
|
|
|
|
|
|
|
|
|
Under Section 7 of GPL version 3, you are granted additional
|
|
|
|
|
permissions described in the GCC Runtime Library Exception, version
|
|
|
|
|
3.1, as published by the Free Software Foundation.
|
|
|
|
|
|
|
|
|
|
You should have received a copy of the GNU General Public License and
|
|
|
|
|
a copy of the GCC Runtime Library Exception along with this program;
|
|
|
|
|
see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
|
|
|
|
|
<http://www.gnu.org/licenses/>. */
|
|
|
|
|
|
|
|
|
|
/* Included after all more target-specific host-config.h. */
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
/* The target may have some OS specific way to implement compare-and-swap. */
|
|
|
|
|
#if !defined(atomic_compare_exchange_n) && SIZE(HAVE_ATOMIC_CAS)
|
|
|
|
|
# define atomic_compare_exchange_n __atomic_compare_exchange_n
|
|
|
|
|
#endif
|
|
|
|
|
#if !defined(atomic_compare_exchange_w) && WSIZE(HAVE_ATOMIC_CAS)
|
|
|
|
|
# define atomic_compare_exchange_w __atomic_compare_exchange_n
|
|
|
|
|
#endif
|
|
|
|
|
|
|
|
|
|
/* For some targets, it may be significantly faster to avoid all barriers
|
|
|
|
|
if the user only wants relaxed memory order. Sometimes we don't want
|
|
|
|
|
the extra code bloat. In all cases, use the input to avoid warnings. */
|
|
|
|
|
#if defined(WANT_SPECIALCASE_RELAXED) && !defined(__OPTIMIZE_SIZE__)
|
|
|
|
|
# define maybe_specialcase_relaxed(x) ((x) == __ATOMIC_RELAXED)
|
|
|
|
|
#else
|
|
|
|
|
# define maybe_specialcase_relaxed(x) ((x) & 0)
|
|
|
|
|
#endif
|
|
|
|
|
|
|
|
|
|
/* Similar, but for targets for which the seq_cst model is sufficiently
|
|
|
|
|
more expensive than the acq_rel model. */
|
|
|
|
|
#if defined(WANT_SPECIALCASE_ACQREL) && !defined(__OPTIMIZE_SIZE__)
|
|
|
|
|
# define maybe_specialcase_acqrel(x) ((x) != __ATOMIC_SEQ_CST)
|
|
|
|
|
#else
|
|
|
|
|
# define maybe_specialcase_acqrel(x) ((x) & 0)
|
|
|
|
|
#endif
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
/* The target may have some OS specific way to emit barriers. */
|
|
|
|
|
#ifndef pre_post_barrier
|
|
|
|
|
static inline void __attribute__((always_inline, artificial))
|
|
|
|
|
pre_barrier(int model)
|
|
|
|
|
{
|
|
|
|
|
if (!maybe_specialcase_relaxed(model))
|
|
|
|
|
{
|
|
|
|
|
if (maybe_specialcase_acqrel(model))
|
|
|
|
|
__atomic_thread_fence (__ATOMIC_ACQ_REL);
|
|
|
|
|
else
|
|
|
|
|
__atomic_thread_fence (__ATOMIC_SEQ_CST);
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
static inline void __attribute__((always_inline, artificial))
|
|
|
|
|
post_barrier(int model)
|
|
|
|
|
{
|
|
|
|
|
pre_barrier(model);
|
|
|
|
|
}
|
|
|
|
|
#define pre_post_barrier 1
|
|
|
|
|
#endif /* pre_post_barrier */
|
|
|
|
|
|
|
|
|
|
/* Similar, but assume that acq_rel is already handled via locks. */
|
|
|
|
|
#ifndef pre_post_seq_barrier
|
|
|
|
|
static inline void __attribute__((always_inline, artificial))
|
|
|
|
|
pre_seq_barrier(int model)
|
|
|
|
|
{
|
|
|
|
|
}
|
|
|
|
|
static inline void __attribute__((always_inline, artificial))
|
|
|
|
|
post_seq_barrier(int model)
|
|
|
|
|
{
|
|
|
|
|
}
|
|
|
|
|
#define pre_post_seq_barrier 1
|
|
|
|
|
#endif
|
