| /* Copyright (C) 2012-2022 Free Software Foundation, Inc. |
| 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 |