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freebsd-skq/include/stdatomic.h
tijl 762446dfda - Simplify the implementation of atomic_compare_exchange_strong_explicit. 
- Evaluate the memory order argument in atomic_fetch_*_explicit macros.
- Implement atomic_store_explicit using atomic_exchange_explicit instead
  of a plain assignment.

Reviewed by:	theraven
MFC after:	2 weeks
2012-09-30 17:33:30 +00:00

328 lines
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/*-
* Copyright (c) 2011 Ed Schouten <ed@FreeBSD.org>
* David Chisnall <theraven@FreeBSD.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#ifndef _STDATOMIC_H_
#define _STDATOMIC_H_
#include <sys/cdefs.h>
#include <sys/_types.h>
#if __has_extension(c_atomic) || __has_extension(cxx_atomic)
#define __CLANG_ATOMICS
#elif __GNUC_PREREQ__(4, 7)
#define __GNUC_ATOMICS
#elif !defined(__GNUC__)
#error "stdatomic.h does not support your compiler"
#endif
#if !defined(__CLANG_ATOMICS)
#define _Atomic(T) struct { volatile T __val; }
#endif
/*
* 7.17.2 Initialization.
*/
#if defined(__CLANG_ATOMICS)
#define ATOMIC_VAR_INIT(value) (value)
#define atomic_init(obj, value) __c11_atomic_init(obj, value)
#else
#define ATOMIC_VAR_INIT(value) { .__val = (value) }
#define atomic_init(obj, value) ((void)((obj)->__val = (value)))
#endif
/*
* Clang and recent GCC both provide predefined macros for the memory
* orderings. If we are using a compiler that doesn't define them, use the
* clang values - these will be ignored in the fallback path.
*/
#ifndef __ATOMIC_RELAXED
#define __ATOMIC_RELAXED 0
#endif
#ifndef __ATOMIC_CONSUME
#define __ATOMIC_CONSUME 1
#endif
#ifndef __ATOMIC_ACQUIRE
#define __ATOMIC_ACQUIRE 2
#endif
#ifndef __ATOMIC_RELEASE
#define __ATOMIC_RELEASE 3
#endif
#ifndef __ATOMIC_ACQ_REL
#define __ATOMIC_ACQ_REL 4
#endif
#ifndef __ATOMIC_SEQ_CST
#define __ATOMIC_SEQ_CST 5
#endif
/*
* 7.17.3 Order and consistency.
*
* The memory_order_* constants that denote the barrier behaviour of the
* atomic operations.
*/
enum memory_order {
memory_order_relaxed = __ATOMIC_RELAXED,
memory_order_consume = __ATOMIC_CONSUME,
memory_order_acquire = __ATOMIC_ACQUIRE,
memory_order_release = __ATOMIC_RELEASE,
memory_order_acq_rel = __ATOMIC_ACQ_REL,
memory_order_seq_cst = __ATOMIC_SEQ_CST
};
/*
* 7.17.4 Fences.
*/
#ifdef __CLANG_ATOMICS
#define atomic_thread_fence(order) __c11_atomic_thread_fence(order)
#define atomic_signal_fence(order) __c11_atomic_signal_fence(order)
#elif defined(__GNUC_ATOMICS)
#define atomic_thread_fence(order) __atomic_thread_fence(order)
#define atomic_signal_fence(order) __atomic_signal_fence(order)
#else
#define atomic_thread_fence(order) ((void)(order), __sync_synchronize())
#define atomic_signal_fence(order) __extension__ ({ \
(void)(order); \
__asm volatile ("" ::: "memory"); \
(void)0; \
})
#endif
/*
* 7.17.5 Lock-free property.
*/
#if defined(__CLANG_ATOMICS) || defined(__GNUC_ATOMICS)
#define atomic_is_lock_free(obj) \
__atomic_is_lock_free(sizeof((obj)->__val), &(obj)->val)
#else
#define atomic_is_lock_free(obj) \
((void)(obj), sizeof((obj)->__val) <= sizeof(void *))
#endif
/*
* 7.17.6 Atomic integer types.
*/
typedef _Atomic(_Bool) atomic_bool;
typedef _Atomic(char) atomic_char;
typedef _Atomic(signed char) atomic_schar;
typedef _Atomic(unsigned char) atomic_uchar;
typedef _Atomic(short) atomic_short;
typedef _Atomic(unsigned short) atomic_ushort;
typedef _Atomic(int) atomic_int;
typedef _Atomic(unsigned int) atomic_uint;
typedef _Atomic(long) atomic_long;
typedef _Atomic(unsigned long) atomic_ulong;
typedef _Atomic(long long) atomic_llong;
typedef _Atomic(unsigned long long) atomic_ullong;
#if 0
typedef _Atomic(__char16_t) atomic_char16_t;
typedef _Atomic(__char32_t) atomic_char32_t;
#endif
typedef _Atomic(__wchar_t) atomic_wchar_t;
typedef _Atomic(__int_least8_t) atomic_int_least8_t;
typedef _Atomic(__uint_least8_t) atomic_uint_least8_t;
typedef _Atomic(__int_least16_t) atomic_int_least16_t;
typedef _Atomic(__uint_least16_t) atomic_uint_least16_t;
typedef _Atomic(__int_least32_t) atomic_int_least32_t;
typedef _Atomic(__uint_least32_t) atomic_uint_least32_t;
typedef _Atomic(__int_least64_t) atomic_int_least64_t;
typedef _Atomic(__uint_least64_t) atomic_uint_least64_t;
typedef _Atomic(__int_fast8_t) atomic_int_fast8_t;
typedef _Atomic(__uint_fast8_t) atomic_uint_fast8_t;
typedef _Atomic(__int_fast16_t) atomic_int_fast16_t;
typedef _Atomic(__uint_fast16_t) atomic_uint_fast16_t;
typedef _Atomic(__int_fast32_t) atomic_int_fast32_t;
typedef _Atomic(__uint_fast32_t) atomic_uint_fast32_t;
typedef _Atomic(__int_fast64_t) atomic_int_fast64_t;
typedef _Atomic(__uint_fast64_t) atomic_uint_fast64_t;
typedef _Atomic(__intptr_t) atomic_intptr_t;
typedef _Atomic(__uintptr_t) atomic_uintptr_t;
typedef _Atomic(__size_t) atomic_size_t;
typedef _Atomic(__ptrdiff_t) atomic_ptrdiff_t;
typedef _Atomic(__intmax_t) atomic_intmax_t;
typedef _Atomic(__uintmax_t) atomic_uintmax_t;
/*
* 7.17.7 Operations on atomic types.
*/
/*
* Compiler-specific operations.
*/
#if defined(__CLANG_ATOMICS)
#define atomic_compare_exchange_strong_explicit(object, expected, \
desired, success, failure) \
__c11_atomic_compare_exchange_strong(object, expected, desired, \
success, failure)
#define atomic_compare_exchange_weak_explicit(object, expected, \
desired, success, failure) \
__c11_atomic_compare_exchange_weak(object, expected, desired, \
success, failure)
#define atomic_exchange_explicit(object, desired, order) \
__c11_atomic_exchange(object, desired, order)
#define atomic_fetch_add_explicit(object, operand, order) \
__c11_atomic_fetch_add(object, operand, order)
#define atomic_fetch_and_explicit(object, operand, order) \
__c11_atomic_fetch_and(object, operand, order)
#define atomic_fetch_or_explicit(object, operand, order) \
__c11_atomic_fetch_or(object, operand, order)
#define atomic_fetch_sub_explicit(object, operand, order) \
__c11_atomic_fetch_sub(object, operand, order)
#define atomic_fetch_xor_explicit(object, operand, order) \
__c11_atomic_fetch_xor(object, operand, order)
#define atomic_load_explicit(object, order) \
__c11_atomic_load(object, order)
#define atomic_store_explicit(object, desired, order) \
__c11_atomic_store(object, desired, order)
#elif defined(__GNUC_ATOMICS)
#define atomic_compare_exchange_strong_explicit(object, expected, \
desired, success, failure) \
__atomic_compare_exchange_n(&(object)->__val, expected, \
desired, 0, success, failure)
#define atomic_compare_exchange_weak_explicit(object, expected, \
desired, success, failure) \
__atomic_compare_exchange_n(&(object)->__val, expected, \
desired, 1, success, failure)
#define atomic_exchange_explicit(object, desired, order) \
__atomic_exchange_n(&(object)->__val, desired, order)
#define atomic_fetch_add_explicit(object, operand, order) \
__atomic_fetch_add(&(object)->__val, operand, order)
#define atomic_fetch_and_explicit(object, operand, order) \
__atomic_fetch_and(&(object)->__val, operand, order)
#define atomic_fetch_or_explicit(object, operand, order) \
__atomic_fetch_or(&(object)->__val, operand, order)
#define atomic_fetch_sub_explicit(object, operand, order) \
__atomic_fetch_sub(&(object)->__val, operand, order)
#define atomic_fetch_xor_explicit(object, operand, order) \
__atomic_fetch_xor(&(object)->__val, operand, order)
#define atomic_load_explicit(object, order) \
__atomic_load_n(&(object)->__val, order)
#define atomic_store_explicit(object, desired, order) \
__atomic_store_n(&(object)->__val, desired, order)
#else
#define atomic_compare_exchange_strong_explicit(object, expected, \
desired, success, failure) __extension__ ({ \
__typeof__(expected) __ep = (expected); \
__typeof__(*__ep) __e = *__ep; \
(void)(success); (void)(failure); \
(*__ep = __sync_val_compare_and_swap(&(object)->__val, \
__e, desired)) == __e; \
})
#define atomic_compare_exchange_weak_explicit(object, expected, \
desired, success, failure) \
atomic_compare_exchange_strong_explicit(object, expected, \
desired, success, failure)
#if __has_builtin(__sync_swap)
/* Clang provides a full-barrier atomic exchange - use it if available. */
#define atomic_exchange_explicit(object, desired, order) \
((void)(order), __sync_swap(&(object)->__val, desired))
#else
/*
* __sync_lock_test_and_set() is only an acquire barrier in theory (although in
* practice it is usually a full barrier) so we need an explicit barrier before
* it.
*/
#define atomic_exchange_explicit(object, desired, order) \
__extension__ ({ \
__typeof__(object) __o = (object); \
__typeof__(desired) __d = (desired); \
(void)(order); \
__sync_synchronize(); \
__sync_lock_test_and_set(&(__o)->__val, __d); \
})
#endif
#define atomic_fetch_add_explicit(object, operand, order) \
((void)(order), __sync_fetch_and_add(&(object)->__val, operand))
#define atomic_fetch_and_explicit(object, operand, order) \
((void)(order), __sync_fetch_and_and(&(object)->__val, operand))
#define atomic_fetch_or_explicit(object, operand, order) \
((void)(order), __sync_fetch_and_or(&(object)->__val, operand))
#define atomic_fetch_sub_explicit(object, operand, order) \
((void)(order), __sync_fetch_and_sub(&(object)->__val, operand))
#define atomic_fetch_xor_explicit(object, operand, order) \
((void)(order), __sync_fetch_and_xor(&(object)->__val, operand))
#define atomic_load_explicit(object, order) \
((void)(order), __sync_fetch_and_add(&(object)->__val, 0))
#define atomic_store_explicit(object, desired, order) \
((void)atomic_exchange_explicit(object, desired, order))
#endif
/*
* Convenience functions.
*/
#define atomic_compare_exchange_strong(object, expected, desired) \
atomic_compare_exchange_strong_explicit(object, expected, \
desired, memory_order_seq_cst, memory_order_seq_cst)
#define atomic_compare_exchange_weak(object, expected, desired) \
atomic_compare_exchange_weak_explicit(object, expected, \
desired, memory_order_seq_cst, memory_order_seq_cst)
#define atomic_exchange(object, desired) \
atomic_exchange_explicit(object, desired, memory_order_seq_cst)
#define atomic_fetch_add(object, operand) \
atomic_fetch_add_explicit(object, operand, memory_order_seq_cst)
#define atomic_fetch_and(object, operand) \
atomic_fetch_and_explicit(object, operand, memory_order_seq_cst)
#define atomic_fetch_or(object, operand) \
atomic_fetch_or_explicit(object, operand, memory_order_seq_cst)
#define atomic_fetch_sub(object, operand) \
atomic_fetch_sub_explicit(object, operand, memory_order_seq_cst)
#define atomic_fetch_xor(object, operand) \
atomic_fetch_xor_explicit(object, operand, memory_order_seq_cst)
#define atomic_load(object) \
atomic_load_explicit(object, memory_order_seq_cst)
#define atomic_store(object, desired) \
atomic_store_explicit(object, desired, memory_order_seq_cst)
/*
* 7.17.8 Atomic flag type and operations.
*/
typedef atomic_bool atomic_flag;
#define ATOMIC_FLAG_INIT ATOMIC_VAR_INIT(0)
#define atomic_flag_clear_explicit(object, order) \
atomic_store_explicit(object, 0, order)
#define atomic_flag_test_and_set_explicit(object, order) \
atomic_compare_exchange_strong_explicit(object, 0, 1, order, order)
#define atomic_flag_clear(object) \
atomic_flag_clear_explicit(object, memory_order_seq_cst)
#define atomic_flag_test_and_set(object) \
atomic_flag_test_and_set_explicit(object, memory_order_seq_cst)
#endif /* !_STDATOMIC_H_ */
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