[ceph.git] / ceph / src / boost / boost / atomic / detail / ops_gcc_sync.hpp

/*
 * Distributed under the Boost Software License, Version 1.0.
 * (See accompanying file LICENSE_1_0.txt or copy at
 * http://www.boost.org/LICENSE_1_0.txt)
 *
 * Copyright (c) 2011 Helge Bahmann
 * Copyright (c) 2013 Tim Blechmann
 * Copyright (c) 2014 Andrey Semashev
 */
/*!
 * \file   atomic/detail/ops_gcc_sync.hpp
 *
 * This header contains implementation of the \c operations template.
 */

#ifndef BOOST_ATOMIC_DETAIL_OPS_GCC_SYNC_HPP_INCLUDED_
#define BOOST_ATOMIC_DETAIL_OPS_GCC_SYNC_HPP_INCLUDED_

#include <cstddef>
#include <boost/memory_order.hpp>
#include <boost/atomic/detail/config.hpp>
#include <boost/atomic/detail/storage_traits.hpp>
#include <boost/atomic/detail/operations_fwd.hpp>
#include <boost/atomic/detail/ops_extending_cas_based.hpp>
#include <boost/atomic/capabilities.hpp>

#ifdef BOOST_HAS_PRAGMA_ONCE
#pragma once
#endif

namespace boost {
namespace atomics {
namespace detail {

struct gcc_sync_operations_base
{
    static BOOST_CONSTEXPR_OR_CONST bool full_cas_based = false;
    static BOOST_CONSTEXPR_OR_CONST bool is_always_lock_free = true;

    static BOOST_FORCEINLINE void fence_before_store(memory_order order) BOOST_NOEXCEPT
    {
        if ((static_cast< unsigned int >(order) & static_cast< unsigned int >(memory_order_release)) != 0u)
            __sync_synchronize();
    }

    static BOOST_FORCEINLINE void fence_after_store(memory_order order) BOOST_NOEXCEPT
    {
        if (order == memory_order_seq_cst)
            __sync_synchronize();
    }

    static BOOST_FORCEINLINE void fence_after_load(memory_order order) BOOST_NOEXCEPT
    {
        if ((static_cast< unsigned int >(order) & (static_cast< unsigned int >(memory_order_acquire) | static_cast< unsigned int >(memory_order_consume))) != 0u)
            __sync_synchronize();
    }
};

template< std::size_t Size, bool Signed >
struct gcc_sync_operations :
    public gcc_sync_operations_base
{
    typedef typename storage_traits< Size >::type storage_type;

    static BOOST_CONSTEXPR_OR_CONST std::size_t storage_size = Size;
    static BOOST_CONSTEXPR_OR_CONST std::size_t storage_alignment = storage_traits< Size >::alignment;
    static BOOST_CONSTEXPR_OR_CONST bool is_signed = Signed;

    static BOOST_FORCEINLINE void store(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
    {
        fence_before_store(order);
        storage = v;
        fence_after_store(order);
    }

    static BOOST_FORCEINLINE storage_type load(storage_type const volatile& storage, memory_order order) BOOST_NOEXCEPT
    {
        storage_type v = storage;
        fence_after_load(order);
        return v;
    }

    static BOOST_FORCEINLINE storage_type fetch_add(storage_type volatile& storage, storage_type v, memory_order) BOOST_NOEXCEPT
    {
        return __sync_fetch_and_add(&storage, v);
    }

    static BOOST_FORCEINLINE storage_type fetch_sub(storage_type volatile& storage, storage_type v, memory_order) BOOST_NOEXCEPT
    {
        return __sync_fetch_and_sub(&storage, v);
    }

    static BOOST_FORCEINLINE storage_type exchange(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
    {
        // GCC docs mention that not all architectures may support full exchange semantics for this intrinsic. However, GCC's implementation of
        // std::atomic<> uses this intrinsic unconditionally. We do so as well. In case if some architectures actually don't support this, we can always
        // add a check here and fall back to a CAS loop.
        if ((static_cast< unsigned int >(order) & static_cast< unsigned int >(memory_order_release)) != 0u)
            __sync_synchronize();
        return __sync_lock_test_and_set(&storage, v);
    }

    static BOOST_FORCEINLINE bool compare_exchange_strong(
        storage_type volatile& storage, storage_type& expected, storage_type desired, memory_order, memory_order) BOOST_NOEXCEPT
    {
        storage_type expected2 = expected;
        storage_type old_val = __sync_val_compare_and_swap(&storage, expected2, desired);

        if (old_val == expected2)
        {
            return true;
        }
        else
        {
            expected = old_val;
            return false;
        }
    }

    static BOOST_FORCEINLINE bool compare_exchange_weak(
        storage_type volatile& storage, storage_type& expected, storage_type desired, memory_order success_order, memory_order failure_order) BOOST_NOEXCEPT
    {
        return compare_exchange_strong(storage, expected, desired, success_order, failure_order);
    }

    static BOOST_FORCEINLINE storage_type fetch_and(storage_type volatile& storage, storage_type v, memory_order) BOOST_NOEXCEPT
    {
        return __sync_fetch_and_and(&storage, v);
    }

    static BOOST_FORCEINLINE storage_type fetch_or(storage_type volatile& storage, storage_type v, memory_order) BOOST_NOEXCEPT
    {
        return __sync_fetch_and_or(&storage, v);
    }

    static BOOST_FORCEINLINE storage_type fetch_xor(storage_type volatile& storage, storage_type v, memory_order) BOOST_NOEXCEPT
    {
        return __sync_fetch_and_xor(&storage, v);
    }

    static BOOST_FORCEINLINE bool test_and_set(storage_type volatile& storage, memory_order order) BOOST_NOEXCEPT
    {
        if ((static_cast< unsigned int >(order) & static_cast< unsigned int >(memory_order_release)) != 0u)
            __sync_synchronize();
        return !!__sync_lock_test_and_set(&storage, 1);
    }

    static BOOST_FORCEINLINE void clear(storage_type volatile& storage, memory_order order) BOOST_NOEXCEPT
    {
        __sync_lock_release(&storage);
        if (order == memory_order_seq_cst)
            __sync_synchronize();
    }
};

#if BOOST_ATOMIC_INT8_LOCK_FREE > 0
template< bool Signed >
struct operations< 1u, Signed > :
#if defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_1)
    public gcc_sync_operations< 1u, Signed >
#elif defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_2)
    public extending_cas_based_operations< gcc_sync_operations< 2u, Signed >, 1u, Signed >
#elif defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4)
    public extending_cas_based_operations< gcc_sync_operations< 4u, Signed >, 1u, Signed >
#elif defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_8)
    public extending_cas_based_operations< gcc_sync_operations< 8u, Signed >, 1u, Signed >
#else
    public extending_cas_based_operations< gcc_sync_operations< 16u, Signed >, 1u, Signed >
#endif
{
};
#endif

#if BOOST_ATOMIC_INT16_LOCK_FREE > 0
template< bool Signed >
struct operations< 2u, Signed > :
#if defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_2)
    public gcc_sync_operations< 2u, Signed >
#elif defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4)
    public extending_cas_based_operations< gcc_sync_operations< 4u, Signed >, 2u, Signed >
#elif defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_8)
    public extending_cas_based_operations< gcc_sync_operations< 8u, Signed >, 2u, Signed >
#else
    public extending_cas_based_operations< gcc_sync_operations< 16u, Signed >, 2u, Signed >
#endif
{
};
#endif

#if BOOST_ATOMIC_INT32_LOCK_FREE > 0
template< bool Signed >
struct operations< 4u, Signed > :
#if defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4)
    public gcc_sync_operations< 4u, Signed >
#elif defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_8)
    public extending_cas_based_operations< gcc_sync_operations< 8u, Signed >, 4u, Signed >
#else
    public extending_cas_based_operations< gcc_sync_operations< 16u, Signed >, 4u, Signed >
#endif
{
};
#endif

#if BOOST_ATOMIC_INT64_LOCK_FREE > 0
template< bool Signed >
struct operations< 8u, Signed > :
#if defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_8)
    public gcc_sync_operations< 8u, Signed >
#else
    public extending_cas_based_operations< gcc_sync_operations< 16u, Signed >, 8u, Signed >
#endif
{
};
#endif

#if BOOST_ATOMIC_INT128_LOCK_FREE > 0
template< bool Signed >
struct operations< 16u, Signed > :
    public gcc_sync_operations< 16u, Signed >
{
};
#endif

BOOST_FORCEINLINE void thread_fence(memory_order order) BOOST_NOEXCEPT
{
    if (order != memory_order_relaxed)
        __sync_synchronize();
}

BOOST_FORCEINLINE void signal_fence(memory_order order) BOOST_NOEXCEPT
{
    if (order != memory_order_relaxed)
        __asm__ __volatile__ ("" ::: "memory");
}

} // namespace detail
} // namespace atomics
} // namespace boost

#endif // BOOST_ATOMIC_DETAIL_OPS_GCC_SYNC_HPP_INCLUDED_
Commit	Line	Data
7c673cae FG	1	/*
	2	* Distributed under the Boost Software License, Version 1.0.
	3	* (See accompanying file LICENSE_1_0.txt or copy at
	4	* http://www.boost.org/LICENSE_1_0.txt)
	5	*
	6	* Copyright (c) 2011 Helge Bahmann
	7	* Copyright (c) 2013 Tim Blechmann
	8	* Copyright (c) 2014 Andrey Semashev
	9	*/
	10	/*!
	11	* \file atomic/detail/ops_gcc_sync.hpp
	12	*
	13	* This header contains implementation of the \c operations template.
	14	*/
	15
	16	#ifndef BOOST_ATOMIC_DETAIL_OPS_GCC_SYNC_HPP_INCLUDED_
	17	#define BOOST_ATOMIC_DETAIL_OPS_GCC_SYNC_HPP_INCLUDED_
	18
b32b8144	19	#include <cstddef>
7c673cae FG	20	#include <boost/memory_order.hpp>
7c673cae FG	21	#include <boost/atomic/detail/config.hpp>
f67539c2	22	#include <boost/atomic/detail/storage_traits.hpp>
7c673cae FG	23	#include <boost/atomic/detail/operations_fwd.hpp>
	24	#include <boost/atomic/detail/ops_extending_cas_based.hpp>
	25	#include <boost/atomic/capabilities.hpp>
	26
	27	#ifdef BOOST_HAS_PRAGMA_ONCE
	28	#pragma once
	29	#endif
	30
	31	namespace boost {
	32	namespace atomics {
	33	namespace detail {
	34
	35	struct gcc_sync_operations_base
	36	{
11fdf7f2	37	static BOOST_CONSTEXPR_OR_CONST bool full_cas_based = false;
7c673cae FG	38	static BOOST_CONSTEXPR_OR_CONST bool is_always_lock_free = true;
	39
	40	static BOOST_FORCEINLINE void fence_before_store(memory_order order) BOOST_NOEXCEPT
	41	{
11fdf7f2	42	if ((static_cast< unsigned int >(order) & static_cast< unsigned int >(memory_order_release)) != 0u)
7c673cae FG	43	__sync_synchronize();
	44	}
	45
	46	static BOOST_FORCEINLINE void fence_after_store(memory_order order) BOOST_NOEXCEPT
	47	{
	48	if (order == memory_order_seq_cst)
	49	__sync_synchronize();
	50	}
	51
	52	static BOOST_FORCEINLINE void fence_after_load(memory_order order) BOOST_NOEXCEPT
	53	{
11fdf7f2	54	if ((static_cast< unsigned int >(order) & (static_cast< unsigned int >(memory_order_acquire) \| static_cast< unsigned int >(memory_order_consume))) != 0u)
7c673cae FG	55	__sync_synchronize();
	56	}
	57	};
	58
11fdf7f2	59	template< std::size_t Size, bool Signed >
7c673cae FG	60	struct gcc_sync_operations :
	61	public gcc_sync_operations_base
	62	{
f67539c2	63	typedef typename storage_traits< Size >::type storage_type;
11fdf7f2 TL	64
11fdf7f2 TL	65	static BOOST_CONSTEXPR_OR_CONST std::size_t storage_size = Size;
f67539c2	66	static BOOST_CONSTEXPR_OR_CONST std::size_t storage_alignment = storage_traits< Size >::alignment;
11fdf7f2	67	static BOOST_CONSTEXPR_OR_CONST bool is_signed = Signed;
7c673cae FG	68
	69	static BOOST_FORCEINLINE void store(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
	70	{
	71	fence_before_store(order);
	72	storage = v;
	73	fence_after_store(order);
	74	}
	75
	76	static BOOST_FORCEINLINE storage_type load(storage_type const volatile& storage, memory_order order) BOOST_NOEXCEPT
	77	{
	78	storage_type v = storage;
	79	fence_after_load(order);
	80	return v;
	81	}
	82
	83	static BOOST_FORCEINLINE storage_type fetch_add(storage_type volatile& storage, storage_type v, memory_order) BOOST_NOEXCEPT
	84	{
	85	return __sync_fetch_and_add(&storage, v);
	86	}
	87
	88	static BOOST_FORCEINLINE storage_type fetch_sub(storage_type volatile& storage, storage_type v, memory_order) BOOST_NOEXCEPT
	89	{
	90	return __sync_fetch_and_sub(&storage, v);
	91	}
	92
	93	static BOOST_FORCEINLINE storage_type exchange(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
	94	{
	95	// GCC docs mention that not all architectures may support full exchange semantics for this intrinsic. However, GCC's implementation of
	96	// std::atomic<> uses this intrinsic unconditionally. We do so as well. In case if some architectures actually don't support this, we can always
	97	// add a check here and fall back to a CAS loop.
11fdf7f2	98	if ((static_cast< unsigned int >(order) & static_cast< unsigned int >(memory_order_release)) != 0u)
7c673cae FG	99	__sync_synchronize();
	100	return __sync_lock_test_and_set(&storage, v);
	101	}
	102
	103	static BOOST_FORCEINLINE bool compare_exchange_strong(
	104	storage_type volatile& storage, storage_type& expected, storage_type desired, memory_order, memory_order) BOOST_NOEXCEPT
	105	{
	106	storage_type expected2 = expected;
	107	storage_type old_val = __sync_val_compare_and_swap(&storage, expected2, desired);
	108
	109	if (old_val == expected2)
	110	{
	111	return true;
	112	}
	113	else
	114	{
	115	expected = old_val;
	116	return false;
	117	}
	118	}
	119
	120	static BOOST_FORCEINLINE bool compare_exchange_weak(
	121	storage_type volatile& storage, storage_type& expected, storage_type desired, memory_order success_order, memory_order failure_order) BOOST_NOEXCEPT
	122	{
	123	return compare_exchange_strong(storage, expected, desired, success_order, failure_order);
	124	}
	125
	126	static BOOST_FORCEINLINE storage_type fetch_and(storage_type volatile& storage, storage_type v, memory_order) BOOST_NOEXCEPT
	127	{
	128	return __sync_fetch_and_and(&storage, v);
	129	}
	130
	131	static BOOST_FORCEINLINE storage_type fetch_or(storage_type volatile& storage, storage_type v, memory_order) BOOST_NOEXCEPT
	132	{
	133	return __sync_fetch_and_or(&storage, v);
	134	}
	135
	136	static BOOST_FORCEINLINE storage_type fetch_xor(storage_type volatile& storage, storage_type v, memory_order) BOOST_NOEXCEPT
	137	{
	138	return __sync_fetch_and_xor(&storage, v);
	139	}
	140
	141	static BOOST_FORCEINLINE bool test_and_set(storage_type volatile& storage, memory_order order) BOOST_NOEXCEPT
	142	{
11fdf7f2	143	if ((static_cast< unsigned int >(order) & static_cast< unsigned int >(memory_order_release)) != 0u)
7c673cae FG	144	__sync_synchronize();
	145	return !!__sync_lock_test_and_set(&storage, 1);
	146	}
	147
	148	static BOOST_FORCEINLINE void clear(storage_type volatile& storage, memory_order order) BOOST_NOEXCEPT
	149	{
	150	__sync_lock_release(&storage);
	151	if (order == memory_order_seq_cst)
	152	__sync_synchronize();
	153	}
7c673cae FG	154	};
	155
	156	#if BOOST_ATOMIC_INT8_LOCK_FREE > 0
	157	template< bool Signed >
	158	struct operations< 1u, Signed > :
	159	#if defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_1)
11fdf7f2	160	public gcc_sync_operations< 1u, Signed >
7c673cae	161	#elif defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_2)
11fdf7f2	162	public extending_cas_based_operations< gcc_sync_operations< 2u, Signed >, 1u, Signed >
7c673cae	163	#elif defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4)
11fdf7f2	164	public extending_cas_based_operations< gcc_sync_operations< 4u, Signed >, 1u, Signed >
7c673cae	165	#elif defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_8)
11fdf7f2	166	public extending_cas_based_operations< gcc_sync_operations< 8u, Signed >, 1u, Signed >
7c673cae	167	#else
11fdf7f2	168	public extending_cas_based_operations< gcc_sync_operations< 16u, Signed >, 1u, Signed >
7c673cae FG	169	#endif
7c673cae FG	170	{
7c673cae FG	171	};
	172	#endif
	173
	174	#if BOOST_ATOMIC_INT16_LOCK_FREE > 0
	175	template< bool Signed >
	176	struct operations< 2u, Signed > :
	177	#if defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_2)
11fdf7f2	178	public gcc_sync_operations< 2u, Signed >
7c673cae	179	#elif defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4)
11fdf7f2	180	public extending_cas_based_operations< gcc_sync_operations< 4u, Signed >, 2u, Signed >
7c673cae	181	#elif defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_8)
11fdf7f2	182	public extending_cas_based_operations< gcc_sync_operations< 8u, Signed >, 2u, Signed >
7c673cae	183	#else
11fdf7f2	184	public extending_cas_based_operations< gcc_sync_operations< 16u, Signed >, 2u, Signed >
7c673cae FG	185	#endif
7c673cae FG	186	{
7c673cae FG	187	};
	188	#endif
	189
	190	#if BOOST_ATOMIC_INT32_LOCK_FREE > 0
	191	template< bool Signed >
	192	struct operations< 4u, Signed > :
	193	#if defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4)
11fdf7f2	194	public gcc_sync_operations< 4u, Signed >
7c673cae	195	#elif defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_8)
11fdf7f2	196	public extending_cas_based_operations< gcc_sync_operations< 8u, Signed >, 4u, Signed >
7c673cae	197	#else
11fdf7f2	198	public extending_cas_based_operations< gcc_sync_operations< 16u, Signed >, 4u, Signed >
7c673cae FG	199	#endif
7c673cae FG	200	{
7c673cae FG	201	};
	202	#endif
	203
	204	#if BOOST_ATOMIC_INT64_LOCK_FREE > 0
	205	template< bool Signed >
	206	struct operations< 8u, Signed > :
	207	#if defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_8)
11fdf7f2	208	public gcc_sync_operations< 8u, Signed >
7c673cae	209	#else
11fdf7f2	210	public extending_cas_based_operations< gcc_sync_operations< 16u, Signed >, 8u, Signed >
7c673cae FG	211	#endif
7c673cae FG	212	{
7c673cae FG	213	};
	214	#endif
	215
	216	#if BOOST_ATOMIC_INT128_LOCK_FREE > 0
	217	template< bool Signed >
	218	struct operations< 16u, Signed > :
11fdf7f2	219	public gcc_sync_operations< 16u, Signed >
7c673cae	220	{
7c673cae FG	221	};
	222	#endif
	223
	224	BOOST_FORCEINLINE void thread_fence(memory_order order) BOOST_NOEXCEPT
	225	{
	226	if (order != memory_order_relaxed)
	227	__sync_synchronize();
	228	}
	229
	230	BOOST_FORCEINLINE void signal_fence(memory_order order) BOOST_NOEXCEPT
	231	{
	232	if (order != memory_order_relaxed)
	233	__asm__ __volatile__ ("" ::: "memory");
	234	}
	235
	236	} // namespace detail
	237	} // namespace atomics
	238	} // namespace boost
	239
	240	#endif // BOOST_ATOMIC_DETAIL_OPS_GCC_SYNC_HPP_INCLUDED_