273 lines
10 KiB
Plaintext
273 lines
10 KiB
Plaintext
/*
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* Distributed under the Boost Software License, Version 1.0.
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* (See accompanying file LICENSE_1_0.txt or copy at
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* http://www.boost.org/LICENSE_1_0.txt)
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*
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* Copyright (c) 2011 Helge Bahmann
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* Copyright (c) 2013 Tim Blechmann
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* Copyright (c) 2014 Andrey Semashev
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*/
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/*!
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* \file atomic/detail/ops_gcc_sync.hpp
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*
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* This header contains implementation of the \c operations template.
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*/
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#ifndef BOOST_ATOMIC_DETAIL_OPS_GCC_SYNC_HPP_INCLUDED_
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#define BOOST_ATOMIC_DETAIL_OPS_GCC_SYNC_HPP_INCLUDED_
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#include <boost/memory_order.hpp>
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#include <boost/atomic/detail/config.hpp>
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#include <boost/atomic/detail/storage_type.hpp>
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#include <boost/atomic/detail/operations_fwd.hpp>
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#include <boost/atomic/detail/ops_extending_cas_based.hpp>
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#include <boost/atomic/capabilities.hpp>
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#ifdef BOOST_HAS_PRAGMA_ONCE
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#pragma once
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#endif
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namespace boost {
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namespace atomics {
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namespace detail {
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struct gcc_sync_operations_base
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{
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static BOOST_CONSTEXPR_OR_CONST bool is_always_lock_free = true;
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static BOOST_FORCEINLINE void fence_before_store(memory_order order) BOOST_NOEXCEPT
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{
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if ((order & memory_order_release) != 0)
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__sync_synchronize();
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}
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static BOOST_FORCEINLINE void fence_after_store(memory_order order) BOOST_NOEXCEPT
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{
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if (order == memory_order_seq_cst)
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__sync_synchronize();
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}
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static BOOST_FORCEINLINE void fence_after_load(memory_order order) BOOST_NOEXCEPT
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{
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if ((order & (memory_order_acquire | memory_order_consume)) != 0)
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__sync_synchronize();
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}
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};
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template< typename T >
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struct gcc_sync_operations :
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public gcc_sync_operations_base
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{
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typedef T storage_type;
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static BOOST_FORCEINLINE void store(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
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{
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fence_before_store(order);
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storage = v;
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fence_after_store(order);
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}
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static BOOST_FORCEINLINE storage_type load(storage_type const volatile& storage, memory_order order) BOOST_NOEXCEPT
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{
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storage_type v = storage;
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fence_after_load(order);
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return v;
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}
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static BOOST_FORCEINLINE storage_type fetch_add(storage_type volatile& storage, storage_type v, memory_order) BOOST_NOEXCEPT
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{
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return __sync_fetch_and_add(&storage, v);
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}
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static BOOST_FORCEINLINE storage_type fetch_sub(storage_type volatile& storage, storage_type v, memory_order) BOOST_NOEXCEPT
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{
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return __sync_fetch_and_sub(&storage, v);
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}
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static BOOST_FORCEINLINE storage_type exchange(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
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{
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// GCC docs mention that not all architectures may support full exchange semantics for this intrinsic. However, GCC's implementation of
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// std::atomic<> uses this intrinsic unconditionally. We do so as well. In case if some architectures actually don't support this, we can always
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// add a check here and fall back to a CAS loop.
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if ((order & memory_order_release) != 0)
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__sync_synchronize();
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return __sync_lock_test_and_set(&storage, v);
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}
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static BOOST_FORCEINLINE bool compare_exchange_strong(
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storage_type volatile& storage, storage_type& expected, storage_type desired, memory_order, memory_order) BOOST_NOEXCEPT
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{
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storage_type expected2 = expected;
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storage_type old_val = __sync_val_compare_and_swap(&storage, expected2, desired);
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if (old_val == expected2)
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{
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return true;
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}
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else
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{
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expected = old_val;
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return false;
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}
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}
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static BOOST_FORCEINLINE bool compare_exchange_weak(
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storage_type volatile& storage, storage_type& expected, storage_type desired, memory_order success_order, memory_order failure_order) BOOST_NOEXCEPT
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{
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return compare_exchange_strong(storage, expected, desired, success_order, failure_order);
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}
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static BOOST_FORCEINLINE storage_type fetch_and(storage_type volatile& storage, storage_type v, memory_order) BOOST_NOEXCEPT
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{
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return __sync_fetch_and_and(&storage, v);
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}
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static BOOST_FORCEINLINE storage_type fetch_or(storage_type volatile& storage, storage_type v, memory_order) BOOST_NOEXCEPT
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{
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return __sync_fetch_and_or(&storage, v);
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}
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static BOOST_FORCEINLINE storage_type fetch_xor(storage_type volatile& storage, storage_type v, memory_order) BOOST_NOEXCEPT
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{
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return __sync_fetch_and_xor(&storage, v);
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}
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static BOOST_FORCEINLINE bool test_and_set(storage_type volatile& storage, memory_order order) BOOST_NOEXCEPT
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{
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if ((order & memory_order_release) != 0)
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__sync_synchronize();
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return !!__sync_lock_test_and_set(&storage, 1);
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}
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static BOOST_FORCEINLINE void clear(storage_type volatile& storage, memory_order order) BOOST_NOEXCEPT
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{
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__sync_lock_release(&storage);
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if (order == memory_order_seq_cst)
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__sync_synchronize();
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}
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static BOOST_FORCEINLINE bool is_lock_free(storage_type const volatile&) BOOST_NOEXCEPT
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{
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return true;
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}
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};
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#if BOOST_ATOMIC_INT8_LOCK_FREE > 0
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template< bool Signed >
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struct operations< 1u, Signed > :
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#if defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_1)
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public gcc_sync_operations< typename make_storage_type< 1u, Signed >::type >
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#elif defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_2)
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public extending_cas_based_operations< gcc_sync_operations< typename make_storage_type< 2u, Signed >::type >, 1u, Signed >
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#elif defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4)
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public extending_cas_based_operations< gcc_sync_operations< typename make_storage_type< 4u, Signed >::type >, 1u, Signed >
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#elif defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_8)
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public extending_cas_based_operations< gcc_sync_operations< typename make_storage_type< 8u, Signed >::type >, 1u, Signed >
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#else
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public extending_cas_based_operations< gcc_sync_operations< typename make_storage_type< 16u, Signed >::type >, 1u, Signed >
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#endif
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{
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#if defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_1)
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typedef typename make_storage_type< 1u, Signed >::aligned aligned_storage_type;
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#elif defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_2)
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typedef typename make_storage_type< 2u, Signed >::aligned aligned_storage_type;
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#elif defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4)
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typedef typename make_storage_type< 4u, Signed >::aligned aligned_storage_type;
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#elif defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_8)
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typedef typename make_storage_type< 8u, Signed >::aligned aligned_storage_type;
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#else
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typedef typename make_storage_type< 16u, Signed >::aligned aligned_storage_type;
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#endif
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};
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#endif
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#if BOOST_ATOMIC_INT16_LOCK_FREE > 0
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template< bool Signed >
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struct operations< 2u, Signed > :
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#if defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_2)
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public gcc_sync_operations< typename make_storage_type< 2u, Signed >::type >
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#elif defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4)
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public extending_cas_based_operations< gcc_sync_operations< typename make_storage_type< 4u, Signed >::type >, 2u, Signed >
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#elif defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_8)
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public extending_cas_based_operations< gcc_sync_operations< typename make_storage_type< 8u, Signed >::type >, 2u, Signed >
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#else
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public extending_cas_based_operations< gcc_sync_operations< typename make_storage_type< 16u, Signed >::type >, 2u, Signed >
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#endif
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{
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#if defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_2)
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typedef typename make_storage_type< 2u, Signed >::aligned aligned_storage_type;
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#elif defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4)
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typedef typename make_storage_type< 4u, Signed >::aligned aligned_storage_type;
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#elif defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_8)
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typedef typename make_storage_type< 8u, Signed >::aligned aligned_storage_type;
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#else
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typedef typename make_storage_type< 16u, Signed >::aligned aligned_storage_type;
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#endif
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};
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#endif
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#if BOOST_ATOMIC_INT32_LOCK_FREE > 0
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template< bool Signed >
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struct operations< 4u, Signed > :
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#if defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4)
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public gcc_sync_operations< typename make_storage_type< 4u, Signed >::type >
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#elif defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_8)
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public extending_cas_based_operations< gcc_sync_operations< typename make_storage_type< 8u, Signed >::type >, 4u, Signed >
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#else
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public extending_cas_based_operations< gcc_sync_operations< typename make_storage_type< 16u, Signed >::type >, 4u, Signed >
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#endif
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{
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#if defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4)
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typedef typename make_storage_type< 4u, Signed >::aligned aligned_storage_type;
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#elif defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_8)
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typedef typename make_storage_type< 8u, Signed >::aligned aligned_storage_type;
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#else
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typedef typename make_storage_type< 16u, Signed >::aligned aligned_storage_type;
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#endif
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};
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#endif
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#if BOOST_ATOMIC_INT64_LOCK_FREE > 0
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template< bool Signed >
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struct operations< 8u, Signed > :
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#if defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_8)
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public gcc_sync_operations< typename make_storage_type< 8u, Signed >::type >
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#else
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public extending_cas_based_operations< gcc_sync_operations< typename make_storage_type< 16u, Signed >::type >, 8u, Signed >
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#endif
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{
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#if defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_8)
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typedef typename make_storage_type< 8u, Signed >::aligned aligned_storage_type;
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#else
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typedef typename make_storage_type< 16u, Signed >::aligned aligned_storage_type;
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#endif
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};
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#endif
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#if BOOST_ATOMIC_INT128_LOCK_FREE > 0
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template< bool Signed >
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struct operations< 16u, Signed > :
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public gcc_sync_operations< typename make_storage_type< 16u, Signed >::type >
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{
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typedef typename make_storage_type< 16u, Signed >::aligned aligned_storage_type;
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};
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#endif
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BOOST_FORCEINLINE void thread_fence(memory_order order) BOOST_NOEXCEPT
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{
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if (order != memory_order_relaxed)
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__sync_synchronize();
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}
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BOOST_FORCEINLINE void signal_fence(memory_order order) BOOST_NOEXCEPT
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{
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if (order != memory_order_relaxed)
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__asm__ __volatile__ ("" ::: "memory");
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}
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} // namespace detail
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} // namespace atomics
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} // namespace boost
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#endif // BOOST_ATOMIC_DETAIL_OPS_GCC_SYNC_HPP_INCLUDED_
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