Editing: atomic_base.h
// -*- C++ -*- header. // Copyright (C) 2008-2018 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_base.h * This is an internal header file, included by other library headers. * Do not attempt to use it directly. @headername{atomic} */ #ifndef _GLIBCXX_ATOMIC_BASE_H #define _GLIBCXX_ATOMIC_BASE_H 1 #pragma GCC system_header #include <bits/c++config.h> #include <stdint.h> #include <bits/atomic_lockfree_defines.h> #ifndef _GLIBCXX_ALWAYS_INLINE #define _GLIBCXX_ALWAYS_INLINE inline __attribute__((__always_inline__)) #endif namespace std _GLIBCXX_VISIBILITY(default) { _GLIBCXX_BEGIN_NAMESPACE_VERSION /** * @defgroup atomics Atomics * * Components for performing atomic operations. * @{ */ /// Enumeration for memory_order typedef enum memory_order { memory_order_relaxed, memory_order_consume, memory_order_acquire, memory_order_release, memory_order_acq_rel, memory_order_seq_cst } memory_order; enum __memory_order_modifier { __memory_order_mask = 0x0ffff, __memory_order_modifier_mask = 0xffff0000, __memory_order_hle_acquire = 0x10000, __memory_order_hle_release = 0x20000 }; constexpr memory_order operator|(memory_order __m, __memory_order_modifier __mod) { return memory_order(__m | int(__mod)); } constexpr memory_order operator&(memory_order __m, __memory_order_modifier __mod) { return memory_order(__m & int(__mod)); } // Drop release ordering as per [atomics.types.operations.req]/21 constexpr memory_order __cmpexch_failure_order2(memory_order __m) noexcept { return __m == memory_order_acq_rel ? memory_order_acquire : __m == memory_order_release ? memory_order_relaxed : __m; } constexpr memory_order __cmpexch_failure_order(memory_order __m) noexcept { return memory_order(__cmpexch_failure_order2(__m & __memory_order_mask) | (__m & __memory_order_modifier_mask)); } _GLIBCXX_ALWAYS_INLINE void atomic_thread_fence(memory_order __m) noexcept { __atomic_thread_fence(__m); } _GLIBCXX_ALWAYS_INLINE void atomic_signal_fence(memory_order __m) noexcept { __atomic_signal_fence(__m); } /// kill_dependency template<typename _Tp> inline _Tp kill_dependency(_Tp __y) noexcept { _Tp __ret(__y); return __ret; } // Base types for atomics. template<typename _IntTp> struct __atomic_base; #define ATOMIC_VAR_INIT(_VI) { _VI } template<typename _Tp> struct atomic; template<typename _Tp> struct atomic<_Tp*>; /* The target's "set" value for test-and-set may not be exactly 1. */ #if __GCC_ATOMIC_TEST_AND_SET_TRUEVAL == 1 typedef bool __atomic_flag_data_type; #else typedef unsigned char __atomic_flag_data_type; #endif /** * @brief Base type for atomic_flag. * * Base type is POD with data, allowing atomic_flag to derive from * it and meet the standard layout type requirement. In addition to * compatibility with a C interface, this allows different * implementations of atomic_flag to use the same atomic operation * functions, via a standard conversion to the __atomic_flag_base * argument. */ _GLIBCXX_BEGIN_EXTERN_C struct __atomic_flag_base { __atomic_flag_data_type _M_i; }; _GLIBCXX_END_EXTERN_C #define ATOMIC_FLAG_INIT { 0 } /// atomic_flag struct atomic_flag : public __atomic_flag_base { atomic_flag() noexcept = default; ~atomic_flag() noexcept = default; atomic_flag(const atomic_flag&) = delete; atomic_flag& operator=(const atomic_flag&) = delete; atomic_flag& operator=(const atomic_flag&) volatile = delete; // Conversion to ATOMIC_FLAG_INIT. constexpr atomic_flag(bool __i) noexcept : __atomic_flag_base{ _S_init(__i) } { } _GLIBCXX_ALWAYS_INLINE bool test_and_set(memory_order __m = memory_order_seq_cst) noexcept { return __atomic_test_and_set (&_M_i, __m); } _GLIBCXX_ALWAYS_INLINE bool test_and_set(memory_order __m = memory_order_seq_cst) volatile noexcept { return __atomic_test_and_set (&_M_i, __m); } _GLIBCXX_ALWAYS_INLINE void clear(memory_order __m = memory_order_seq_cst) noexcept { memory_order __b = __m & __memory_order_mask; __glibcxx_assert(__b != memory_order_consume); __glibcxx_assert(__b != memory_order_acquire); __glibcxx_assert(__b != memory_order_acq_rel); __atomic_clear (&_M_i, __m); } _GLIBCXX_ALWAYS_INLINE void clear(memory_order __m = memory_order_seq_cst) volatile noexcept { memory_order __b = __m & __memory_order_mask; __glibcxx_assert(__b != memory_order_consume); __glibcxx_assert(__b != memory_order_acquire); __glibcxx_assert(__b != memory_order_acq_rel); __atomic_clear (&_M_i, __m); } private: static constexpr __atomic_flag_data_type _S_init(bool __i) { return __i ? __GCC_ATOMIC_TEST_AND_SET_TRUEVAL : 0; } }; /// Base class for atomic integrals. // // 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 // // 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 expect. template<typename _ITp> struct __atomic_base { private: typedef _ITp __int_type; static constexpr int _S_alignment = sizeof(_ITp) > alignof(_ITp) ? sizeof(_ITp) : alignof(_ITp); alignas(_S_alignment) __int_type _M_i; public: __atomic_base() noexcept = default; ~__atomic_base() noexcept = default; __atomic_base(const __atomic_base&) = delete; __atomic_base& operator=(const __atomic_base&) = delete; __atomic_base& operator=(const __atomic_base&) volatile = delete; // Requires __int_type convertible to _M_i. constexpr __atomic_base(__int_type __i) noexcept : _M_i (__i) { } operator __int_type() const noexcept { return load(); } operator __int_type() const volatile noexcept { return load(); } __int_type operator=(__int_type __i) noexcept { store(__i); return __i; } __int_type operator=(__int_type __i) volatile noexcept { store(__i); return __i; } __int_type operator++(int) noexcept { return fetch_add(1); } __int_type operator++(int) volatile noexcept { return fetch_add(1); } __int_type operator--(int) noexcept { return fetch_sub(1); } __int_type operator--(int) volatile noexcept { return fetch_sub(1); } __int_type operator++() noexcept { return __atomic_add_fetch(&_M_i, 1, memory_order_seq_cst); } __int_type operator++() volatile noexcept { return __atomic_add_fetch(&_M_i, 1, memory_order_seq_cst); } __int_type operator--() noexcept { return __atomic_sub_fetch(&_M_i, 1, memory_order_seq_cst); } __int_type operator--() volatile noexcept { return __atomic_sub_fetch(&_M_i, 1, memory_order_seq_cst); } __int_type operator+=(__int_type __i) noexcept { return __atomic_add_fetch(&_M_i, __i, memory_order_seq_cst); } __int_type operator+=(__int_type __i) volatile noexcept { return __atomic_add_fetch(&_M_i, __i, memory_order_seq_cst); } __int_type operator-=(__int_type __i) noexcept { return __atomic_sub_fetch(&_M_i, __i, memory_order_seq_cst); } __int_type operator-=(__int_type __i) volatile noexcept { return __atomic_sub_fetch(&_M_i, __i, memory_order_seq_cst); } __int_type operator&=(__int_type __i) noexcept { return __atomic_and_fetch(&_M_i, __i, memory_order_seq_cst); } __int_type operator&=(__int_type __i) volatile noexcept { return __atomic_and_fetch(&_M_i, __i, memory_order_seq_cst); } __int_type operator|=(__int_type __i) noexcept { return __atomic_or_fetch(&_M_i, __i, memory_order_seq_cst); } __int_type operator|=(__int_type __i) volatile noexcept { return __atomic_or_fetch(&_M_i, __i, memory_order_seq_cst); } __int_type operator^=(__int_type __i) noexcept { return __atomic_xor_fetch(&_M_i, __i, memory_order_seq_cst); } __int_type operator^=(__int_type __i) volatile noexcept { return __atomic_xor_fetch(&_M_i, __i, memory_order_seq_cst); } bool is_lock_free() const noexcept { // Use a fake, minimally aligned pointer. return __atomic_is_lock_free(sizeof(_M_i), reinterpret_cast<void *>(-__alignof(_M_i))); } bool is_lock_free() const volatile noexcept { // Use a fake, minimally aligned pointer. return __atomic_is_lock_free(sizeof(_M_i), reinterpret_cast<void *>(-__alignof(_M_i))); } _GLIBCXX_ALWAYS_INLINE void store(__int_type __i, memory_order __m = memory_order_seq_cst) noexcept { memory_order __b = __m & __memory_order_mask; __glibcxx_assert(__b != memory_order_acquire); __glibcxx_assert(__b != memory_order_acq_rel); __glibcxx_assert(__b != memory_order_consume); __atomic_store_n(&_M_i, __i, __m); } _GLIBCXX_ALWAYS_INLINE void store(__int_type __i, memory_order __m = memory_order_seq_cst) volatile noexcept { memory_order __b = __m & __memory_order_mask; __glibcxx_assert(__b != memory_order_acquire); __glibcxx_assert(__b != memory_order_acq_rel); __glibcxx_assert(__b != memory_order_consume); __atomic_store_n(&_M_i, __i, __m); } _GLIBCXX_ALWAYS_INLINE __int_type load(memory_order __m = memory_order_seq_cst) const noexcept { memory_order __b = __m & __memory_order_mask; __glibcxx_assert(__b != memory_order_release); __glibcxx_assert(__b != memory_order_acq_rel); return __atomic_load_n(&_M_i, __m); } _GLIBCXX_ALWAYS_INLINE __int_type load(memory_order __m = memory_order_seq_cst) const volatile noexcept { memory_order __b = __m & __memory_order_mask; __glibcxx_assert(__b != memory_order_release); __glibcxx_assert(__b != memory_order_acq_rel); return __atomic_load_n(&_M_i, __m); } _GLIBCXX_ALWAYS_INLINE __int_type exchange(__int_type __i, memory_order __m = memory_order_seq_cst) noexcept { return __atomic_exchange_n(&_M_i, __i, __m); } _GLIBCXX_ALWAYS_INLINE __int_type exchange(__int_type __i, memory_order __m = memory_order_seq_cst) volatile noexcept { return __atomic_exchange_n(&_M_i, __i, __m); } _GLIBCXX_ALWAYS_INLINE bool compare_exchange_weak(__int_type& __i1, __int_type __i2, memory_order __m1, memory_order __m2) noexcept { memory_order __b2 = __m2 & __memory_order_mask; memory_order __b1 = __m1 & __memory_order_mask; __glibcxx_assert(__b2 != memory_order_release); __glibcxx_assert(__b2 != memory_order_acq_rel); __glibcxx_assert(__b2 <= __b1); return __atomic_compare_exchange_n(&_M_i, &__i1, __i2, 1, __m1, __m2); } _GLIBCXX_ALWAYS_INLINE bool compare_exchange_weak(__int_type& __i1, __int_type __i2, memory_order __m1, memory_order __m2) volatile noexcept { memory_order __b2 = __m2 & __memory_order_mask; memory_order __b1 = __m1 & __memory_order_mask; __glibcxx_assert(__b2 != memory_order_release); __glibcxx_assert(__b2 != memory_order_acq_rel); __glibcxx_assert(__b2 <= __b1); return __atomic_compare_exchange_n(&_M_i, &__i1, __i2, 1, __m1, __m2); } _GLIBCXX_ALWAYS_INLINE bool compare_exchange_weak(__int_type& __i1, __int_type __i2, memory_order __m = memory_order_seq_cst) noexcept { return compare_exchange_weak(__i1, __i2, __m, __cmpexch_failure_order(__m)); } _GLIBCXX_ALWAYS_INLINE bool compare_exchange_weak(__int_type& __i1, __int_type __i2, memory_order __m = memory_order_seq_cst) volatile noexcept { return compare_exchange_weak(__i1, __i2, __m, __cmpexch_failure_order(__m)); } _GLIBCXX_ALWAYS_INLINE bool compare_exchange_strong(__int_type& __i1, __int_type __i2, memory_order __m1, memory_order __m2) noexcept { memory_order __b2 = __m2 & __memory_order_mask; memory_order __b1 = __m1 & __memory_order_mask; __glibcxx_assert(__b2 != memory_order_release); __glibcxx_assert(__b2 != memory_order_acq_rel); __glibcxx_assert(__b2 <= __b1); return __atomic_compare_exchange_n(&_M_i, &__i1, __i2, 0, __m1, __m2); } _GLIBCXX_ALWAYS_INLINE bool compare_exchange_strong(__int_type& __i1, __int_type __i2, memory_order __m1, memory_order __m2) volatile noexcept { memory_order __b2 = __m2 & __memory_order_mask; memory_order __b1 = __m1 & __memory_order_mask; __glibcxx_assert(__b2 != memory_order_release); __glibcxx_assert(__b2 != memory_order_acq_rel); __glibcxx_assert(__b2 <= __b1); return __atomic_compare_exchange_n(&_M_i, &__i1, __i2, 0, __m1, __m2); } _GLIBCXX_ALWAYS_INLINE bool compare_exchange_strong(__int_type& __i1, __int_type __i2, memory_order __m = memory_order_seq_cst) noexcept { return compare_exchange_strong(__i1, __i2, __m, __cmpexch_failure_order(__m)); } _GLIBCXX_ALWAYS_INLINE bool compare_exchange_strong(__int_type& __i1, __int_type __i2, memory_order __m = memory_order_seq_cst) volatile noexcept { return compare_exchange_strong(__i1, __i2, __m, __cmpexch_failure_order(__m)); } _GLIBCXX_ALWAYS_INLINE __int_type fetch_add(__int_type __i, memory_order __m = memory_order_seq_cst) noexcept { return __atomic_fetch_add(&_M_i, __i, __m); } _GLIBCXX_ALWAYS_INLINE __int_type fetch_add(__int_type __i, memory_order __m = memory_order_seq_cst) volatile noexcept { return __atomic_fetch_add(&_M_i, __i, __m); } _GLIBCXX_ALWAYS_INLINE __int_type fetch_sub(__int_type __i, memory_order __m = memory_order_seq_cst) noexcept { return __atomic_fetch_sub(&_M_i, __i, __m); } _GLIBCXX_ALWAYS_INLINE __int_type fetch_sub(__int_type __i, memory_order __m = memory_order_seq_cst) volatile noexcept { return __atomic_fetch_sub(&_M_i, __i, __m); } _GLIBCXX_ALWAYS_INLINE __int_type fetch_and(__int_type __i, memory_order __m = memory_order_seq_cst) noexcept { return __atomic_fetch_and(&_M_i, __i, __m); } _GLIBCXX_ALWAYS_INLINE __int_type fetch_and(__int_type __i, memory_order __m = memory_order_seq_cst) volatile noexcept { return __atomic_fetch_and(&_M_i, __i, __m); } _GLIBCXX_ALWAYS_INLINE __int_type fetch_or(__int_type __i, memory_order __m = memory_order_seq_cst) noexcept { return __atomic_fetch_or(&_M_i, __i, __m); } _GLIBCXX_ALWAYS_INLINE __int_type fetch_or(__int_type __i, memory_order __m = memory_order_seq_cst) volatile noexcept { return __atomic_fetch_or(&_M_i, __i, __m); } _GLIBCXX_ALWAYS_INLINE __int_type fetch_xor(__int_type __i, memory_order __m = memory_order_seq_cst) noexcept { return __atomic_fetch_xor(&_M_i, __i, __m); } _GLIBCXX_ALWAYS_INLINE __int_type fetch_xor(__int_type __i, memory_order __m = memory_order_seq_cst) volatile noexcept { return __atomic_fetch_xor(&_M_i, __i, __m); } }; /// Partial specialization for pointer types. template<typename _PTp> struct __atomic_base<_PTp*> { private: typedef _PTp* __pointer_type; __pointer_type _M_p; // Factored out to facilitate explicit specialization. constexpr ptrdiff_t _M_type_size(ptrdiff_t __d) const { return __d * sizeof(_PTp); } constexpr ptrdiff_t _M_type_size(ptrdiff_t __d) const volatile { return __d * sizeof(_PTp); } public: __atomic_base() noexcept = default; ~__atomic_base() noexcept = default; __atomic_base(const __atomic_base&) = delete; __atomic_base& operator=(const __atomic_base&) = delete; __atomic_base& operator=(const __atomic_base&) volatile = delete; // Requires __pointer_type convertible to _M_p. constexpr __atomic_base(__pointer_type __p) noexcept : _M_p (__p) { } operator __pointer_type() const noexcept { return load(); } operator __pointer_type() const volatile noexcept { return load(); } __pointer_type operator=(__pointer_type __p) noexcept { store(__p); return __p; } __pointer_type operator=(__pointer_type __p) volatile noexcept { store(__p); return __p; } __pointer_type operator++(int) noexcept { return fetch_add(1); } __pointer_type operator++(int) volatile noexcept { return fetch_add(1); } __pointer_type operator--(int) noexcept { return fetch_sub(1); } __pointer_type operator--(int) volatile noexcept { return fetch_sub(1); } __pointer_type operator++() noexcept { return __atomic_add_fetch(&_M_p, _M_type_size(1), memory_order_seq_cst); } __pointer_type operator++() volatile noexcept { return __atomic_add_fetch(&_M_p, _M_type_size(1), memory_order_seq_cst); } __pointer_type operator--() noexcept { return __atomic_sub_fetch(&_M_p, _M_type_size(1), memory_order_seq_cst); } __pointer_type operator--() volatile noexcept { return __atomic_sub_fetch(&_M_p, _M_type_size(1), memory_order_seq_cst); } __pointer_type operator+=(ptrdiff_t __d) noexcept { return __atomic_add_fetch(&_M_p, _M_type_size(__d), memory_order_seq_cst); } __pointer_type operator+=(ptrdiff_t __d) volatile noexcept { return __atomic_add_fetch(&_M_p, _M_type_size(__d), memory_order_seq_cst); } __pointer_type operator-=(ptrdiff_t __d) noexcept { return __atomic_sub_fetch(&_M_p, _M_type_size(__d), memory_order_seq_cst); } __pointer_type operator-=(ptrdiff_t __d) volatile noexcept { return __atomic_sub_fetch(&_M_p, _M_type_size(__d), memory_order_seq_cst); } bool is_lock_free() const noexcept { // Produce a fake, minimally aligned pointer. return __atomic_is_lock_free(sizeof(_M_p), reinterpret_cast<void *>(-__alignof(_M_p))); } bool is_lock_free() const volatile noexcept { // Produce a fake, minimally aligned pointer. return __atomic_is_lock_free(sizeof(_M_p), reinterpret_cast<void *>(-__alignof(_M_p))); } _GLIBCXX_ALWAYS_INLINE void store(__pointer_type __p, memory_order __m = memory_order_seq_cst) noexcept { memory_order __b = __m & __memory_order_mask; __glibcxx_assert(__b != memory_order_acquire); __glibcxx_assert(__b != memory_order_acq_rel); __glibcxx_assert(__b != memory_order_consume); __atomic_store_n(&_M_p, __p, __m); } _GLIBCXX_ALWAYS_INLINE void store(__pointer_type __p, memory_order __m = memory_order_seq_cst) volatile noexcept { memory_order __b = __m & __memory_order_mask; __glibcxx_assert(__b != memory_order_acquire); __glibcxx_assert(__b != memory_order_acq_rel); __glibcxx_assert(__b != memory_order_consume); __atomic_store_n(&_M_p, __p, __m); } _GLIBCXX_ALWAYS_INLINE __pointer_type load(memory_order __m = memory_order_seq_cst) const noexcept { memory_order __b = __m & __memory_order_mask; __glibcxx_assert(__b != memory_order_release); __glibcxx_assert(__b != memory_order_acq_rel); return __atomic_load_n(&_M_p, __m); } _GLIBCXX_ALWAYS_INLINE __pointer_type load(memory_order __m = memory_order_seq_cst) const volatile noexcept { memory_order __b = __m & __memory_order_mask; __glibcxx_assert(__b != memory_order_release); __glibcxx_assert(__b != memory_order_acq_rel); return __atomic_load_n(&_M_p, __m); } _GLIBCXX_ALWAYS_INLINE __pointer_type exchange(__pointer_type __p, memory_order __m = memory_order_seq_cst) noexcept { return __atomic_exchange_n(&_M_p, __p, __m); } _GLIBCXX_ALWAYS_INLINE __pointer_type exchange(__pointer_type __p, memory_order __m = memory_order_seq_cst) volatile noexcept { return __atomic_exchange_n(&_M_p, __p, __m); } _GLIBCXX_ALWAYS_INLINE bool compare_exchange_strong(__pointer_type& __p1, __pointer_type __p2, memory_order __m1, memory_order __m2) noexcept { memory_order __b2 = __m2 & __memory_order_mask; memory_order __b1 = __m1 & __memory_order_mask; __glibcxx_assert(__b2 != memory_order_release); __glibcxx_assert(__b2 != memory_order_acq_rel); __glibcxx_assert(__b2 <= __b1); return __atomic_compare_exchange_n(&_M_p, &__p1, __p2, 0, __m1, __m2); } _GLIBCXX_ALWAYS_INLINE bool compare_exchange_strong(__pointer_type& __p1, __pointer_type __p2, memory_order __m1, memory_order __m2) volatile noexcept { memory_order __b2 = __m2 & __memory_order_mask; memory_order __b1 = __m1 & __memory_order_mask; __glibcxx_assert(__b2 != memory_order_release); __glibcxx_assert(__b2 != memory_order_acq_rel); __glibcxx_assert(__b2 <= __b1); return __atomic_compare_exchange_n(&_M_p, &__p1, __p2, 0, __m1, __m2); } _GLIBCXX_ALWAYS_INLINE __pointer_type fetch_add(ptrdiff_t __d, memory_order __m = memory_order_seq_cst) noexcept { return __atomic_fetch_add(&_M_p, _M_type_size(__d), __m); } _GLIBCXX_ALWAYS_INLINE __pointer_type fetch_add(ptrdiff_t __d, memory_order __m = memory_order_seq_cst) volatile noexcept { return __atomic_fetch_add(&_M_p, _M_type_size(__d), __m); } _GLIBCXX_ALWAYS_INLINE __pointer_type fetch_sub(ptrdiff_t __d, memory_order __m = memory_order_seq_cst) noexcept { return __atomic_fetch_sub(&_M_p, _M_type_size(__d), __m); } _GLIBCXX_ALWAYS_INLINE __pointer_type fetch_sub(ptrdiff_t __d, memory_order __m = memory_order_seq_cst) volatile noexcept { return __atomic_fetch_sub(&_M_p, _M_type_size(__d), __m); } }; // @} group atomics _GLIBCXX_END_NAMESPACE_VERSION } // namespace std #endif
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