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// -*- C++ -*- header.
// Copyright (C) 2008, 2009
// Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library 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, or (at your option)
// any later version.
// This library 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/>.
/** @file bits/atomic_2.h
* This is an internal header file, included by other library headers.
* You should not attempt to use it directly.
*/
#ifndef _GLIBCXX_ATOMIC_2_H
#define _GLIBCXX_ATOMIC_2_H 1
#pragma GCC system_header
// _GLIBCXX_BEGIN_NAMESPACE(std)
// 2 == __atomic2 == Always lock-free
// Assumed:
// _GLIBCXX_ATOMIC_BUILTINS_1
// _GLIBCXX_ATOMIC_BUILTINS_2
// _GLIBCXX_ATOMIC_BUILTINS_4
// _GLIBCXX_ATOMIC_BUILTINS_8
namespace __atomic2
{
/// atomic_flag
struct atomic_flag : private __atomic_flag_base
{
atomic_flag() = default;
~atomic_flag() = default;
atomic_flag(const atomic_flag&) = delete;
atomic_flag& operator=(const atomic_flag&) = delete;
atomic_flag(bool __i) { _M_i = __i; } // XXX deleted copy ctor != agg
bool
test_and_set(memory_order __m = memory_order_seq_cst) volatile
{
// Redundant synchronize if built-in for lock is a full barrier.
if (__m != memory_order_acquire && __m != memory_order_acq_rel)
__sync_synchronize();
return __sync_lock_test_and_set(&_M_i, 1);
}
void
clear(memory_order __m = memory_order_seq_cst) volatile
{
__glibcxx_assert(__m != memory_order_consume);
__glibcxx_assert(__m != memory_order_acquire);
__glibcxx_assert(__m != memory_order_acq_rel);
__sync_lock_release(&_M_i);
if (__m != memory_order_acquire && __m != memory_order_acq_rel)
__sync_synchronize();
}
};
/// 29.4.2, address types
struct atomic_address
{
private:
void* _M_i;
public:
atomic_address() = default;
~atomic_address() = default;
atomic_address(const atomic_address&) = delete;
atomic_address& operator=(const atomic_address&) = delete;
atomic_address(void* __v) { _M_i = __v; }
bool
is_lock_free() const volatile
{ return true; }
void
store(void* __v, memory_order __m = memory_order_seq_cst) volatile
{
__glibcxx_assert(__m != memory_order_acquire);
__glibcxx_assert(__m != memory_order_acq_rel);
__glibcxx_assert(__m != memory_order_consume);
if (__m == memory_order_relaxed)
_M_i = __v;
else
{
// write_mem_barrier();
_M_i = __v;
if (__m = memory_order_seq_cst)
__sync_synchronize();
}
}
void*
load(memory_order __m = memory_order_seq_cst) const volatile
{
__glibcxx_assert(__m != memory_order_release);
__glibcxx_assert(__m != memory_order_acq_rel);
__sync_synchronize();
void* __ret = _M_i;
__sync_synchronize();
return __ret;
}
void*
exchange(void* __v, memory_order __m = memory_order_seq_cst) volatile
{
// XXX built-in assumes memory_order_acquire.
return __sync_lock_test_and_set(&_M_i, __v);
}
bool
compare_exchange_weak(void*& __v1, void* __v2, memory_order __m1,
memory_order __m2) volatile
{ return compare_exchange_strong(__v1, __v2, __m1, __m2); }
bool
compare_exchange_weak(void*& __v1, void* __v2,
memory_order __m = memory_order_seq_cst) volatile
{
return compare_exchange_weak(__v1, __v2, __m,
__calculate_memory_order(__m));
}
bool
compare_exchange_strong(void*& __v1, void* __v2, memory_order __m1,
memory_order __m2) volatile
{
__glibcxx_assert(__m2 != memory_order_release);
__glibcxx_assert(__m2 != memory_order_acq_rel);
__glibcxx_assert(__m2 <= __m1);
void* __v1o = __v1;
void* __v1n = __sync_val_compare_and_swap(&_M_i, __v1o, __v2);
// Assume extra stores (of same value) allowed in true case.
__v1 = __v1n;
return __v1o == __v1n;
}
bool
compare_exchange_strong(void*& __v1, void* __v2,
memory_order __m = memory_order_seq_cst) volatile
{
return compare_exchange_strong(__v1, __v2, __m,
__calculate_memory_order(__m));
}
void*
fetch_add(ptrdiff_t __d, memory_order __m = memory_order_seq_cst) volatile
{ return __sync_fetch_and_add(&_M_i, __d); }
void*
fetch_sub(ptrdiff_t __d, memory_order __m = memory_order_seq_cst) volatile
{ return __sync_fetch_and_sub(&_M_i, __d); }
operator void*() const volatile
{ return load(); }
void*
operator=(void* __v) // XXX volatile
{
store(__v);
return __v;
}
void*
operator+=(ptrdiff_t __d) volatile
{ return __sync_add_and_fetch(&_M_i, __d); }
void*
operator-=(ptrdiff_t __d) volatile
{ return __sync_sub_and_fetch(&_M_i, __d); }
};
// 29.3.1 atomic integral types
// For each of the integral types, define atomic_[integral type] struct
//
// atomic_bool bool
// atomic_char char
// atomic_schar signed char
// atomic_uchar unsigned char
// atomic_short short
// atomic_ushort unsigned short
// atomic_int int
// atomic_uint unsigned int
// atomic_long long
// atomic_ulong unsigned long
// atomic_llong long long
// atomic_ullong unsigned long long
// atomic_char16_t char16_t
// atomic_char32_t char32_t
// atomic_wchar_t wchar_t
// Base type.
// NB: Assuming _ITp is an integral scalar type that is 1, 2, 4, or 8 bytes,
// since that is what GCC built-in functions for atomic memory access work on.
template<typename _ITp>
struct __atomic_base
{
private:
typedef _ITp __integral_type;
__integral_type _M_i;
public:
__atomic_base() = default;
~__atomic_base() = default;
__atomic_base(const __atomic_base&) = delete;
__atomic_base& operator=(const __atomic_base&) = delete;
// Requires __integral_type convertible to _M_base._M_i.
__atomic_base(__integral_type __i) { _M_i = __i; }
operator __integral_type() const volatile
{ return load(); }
__integral_type
operator=(__integral_type __i) // XXX volatile
{
store(__i);
return __i;
}
__integral_type
operator++(int) volatile
{ return fetch_add(1); }
__integral_type
operator--(int) volatile
{ return fetch_sub(1); }
__integral_type
operator++() volatile
{ return __sync_add_and_fetch(&_M_i, 1); }
__integral_type
operator--() volatile
{ return __sync_sub_and_fetch(&_M_i, 1); }
__integral_type
operator+=(__integral_type __i) volatile
{ return __sync_add_and_fetch(&_M_i, __i); }
__integral_type
operator-=(__integral_type __i) volatile
{ return __sync_sub_and_fetch(&_M_i, __i); }
__integral_type
operator&=(__integral_type __i) volatile
{ return __sync_and_and_fetch(&_M_i, __i); }
__integral_type
operator|=(__integral_type __i) volatile
{ return __sync_or_and_fetch(&_M_i, __i); }
__integral_type
operator^=(__integral_type __i) volatile
{ return __sync_xor_and_fetch(&_M_i, __i); }
bool
is_lock_free() const volatile
{ return true; }
void
store(__integral_type __i,
memory_order __m = memory_order_seq_cst) volatile
{
__glibcxx_assert(__m != memory_order_acquire);
__glibcxx_assert(__m != memory_order_acq_rel);
__glibcxx_assert(__m != memory_order_consume);
if (__m == memory_order_relaxed)
_M_i = __i;
else
{
// write_mem_barrier();
_M_i = __i;
if (__m = memory_order_seq_cst)
__sync_synchronize();
}
}
__integral_type
load(memory_order __m = memory_order_seq_cst) const volatile
{
__glibcxx_assert(__m != memory_order_release);
__glibcxx_assert(__m != memory_order_acq_rel);
__sync_synchronize();
__integral_type __ret = _M_i;
__sync_synchronize();
return __ret;
}
__integral_type
exchange(__integral_type __i,
memory_order __m = memory_order_seq_cst) volatile
{
// XXX built-in assumes memory_order_acquire.
return __sync_lock_test_and_set(&_M_i, __i);
}
bool
compare_exchange_weak(__integral_type& __i1, __integral_type __i2,
memory_order __m1, memory_order __m2) volatile
{ return compare_exchange_strong(__i1, __i2, __m1, __m2); }
bool
compare_exchange_weak(__integral_type& __i1, __integral_type __i2,
memory_order __m = memory_order_seq_cst) volatile
{
return compare_exchange_weak(__i1, __i2, __m,
__calculate_memory_order(__m));
}
bool
compare_exchange_strong(__integral_type& __i1, __integral_type __i2,
memory_order __m1, memory_order __m2) volatile
{
__glibcxx_assert(__m2 != memory_order_release);
__glibcxx_assert(__m2 != memory_order_acq_rel);
__glibcxx_assert(__m2 <= __m1);
__integral_type __i1o = __i1;
__integral_type __i1n = __sync_val_compare_and_swap(&_M_i, __i1o, __i2);
// Assume extra stores (of same value) allowed in true case.
__i1 = __i1n;
return __i1o == __i1n;
}
bool
compare_exchange_strong(__integral_type& __i1, __integral_type __i2,
memory_order __m = memory_order_seq_cst) volatile
{
return compare_exchange_strong(__i1, __i2, __m,
__calculate_memory_order(__m));
}
__integral_type
fetch_add(__integral_type __i,
memory_order __m = memory_order_seq_cst) volatile
{ return __sync_fetch_and_add(&_M_i, __i); }
__integral_type
fetch_sub(__integral_type __i,
memory_order __m = memory_order_seq_cst) volatile
{ return __sync_fetch_and_sub(&_M_i, __i); }
__integral_type
fetch_and(__integral_type __i,
memory_order __m = memory_order_seq_cst) volatile
{ return __sync_fetch_and_and(&_M_i, __i); }
__integral_type
fetch_or(__integral_type __i,
memory_order __m = memory_order_seq_cst) volatile
{ return __sync_fetch_and_or(&_M_i, __i); }
__integral_type
fetch_xor(__integral_type __i,
memory_order __m = memory_order_seq_cst) volatile
{ return __sync_fetch_and_xor(&_M_i, __i); }
};
/// atomic_bool
// NB: No operators or fetch-operations for this type.
struct atomic_bool
{
private:
__atomic_base<bool> _M_base;
public:
atomic_bool() = default;
~atomic_bool() = default;
atomic_bool(const atomic_bool&) = delete;
atomic_bool& operator=(const atomic_bool&) = delete;
atomic_bool(bool __i) : _M_base(__i) { }
bool
operator=(bool __i) // XXX volatile
{ return _M_base.operator=(__i); }
operator bool() const volatile
{ return _M_base.load(); }
bool
is_lock_free() const volatile
{ return _M_base.is_lock_free(); }
void
store(bool __i, memory_order __m = memory_order_seq_cst) volatile
{ _M_base.store(__i, __m); }
bool
load(memory_order __m = memory_order_seq_cst) const volatile
{ return _M_base.load(__m); }
bool
exchange(bool __i, memory_order __m = memory_order_seq_cst) volatile
{ return _M_base.exchange(__i, __m); }
bool
compare_exchange_weak(bool& __i1, bool __i2, memory_order __m1,
memory_order __m2) volatile
{ return _M_base.compare_exchange_weak(__i1, __i2, __m1, __m2); }
bool
compare_exchange_weak(bool& __i1, bool __i2,
memory_order __m = memory_order_seq_cst) volatile
{ return _M_base.compare_exchange_weak(__i1, __i2, __m); }
bool
compare_exchange_strong(bool& __i1, bool __i2, memory_order __m1,
memory_order __m2) volatile
{ return _M_base.compare_exchange_strong(__i1, __i2, __m1, __m2); }
bool
compare_exchange_strong(bool& __i1, bool __i2,
memory_order __m = memory_order_seq_cst) volatile
{ return _M_base.compare_exchange_strong(__i1, __i2, __m); }
};
} // namespace __atomic2
// _GLIBCXX_END_NAMESPACE
#endif