1// -*- C++ -*- header. 2 3// Copyright (C) 2008, 2009 4// Free Software Foundation, Inc. 5// 6// This file is part of the GNU ISO C++ Library. This library is free 7// software; you can redistribute it and/or modify it under the 8// terms of the GNU General Public License as published by the 9// Free Software Foundation; either version 3, or (at your option) 10// any later version. 11 12// This library is distributed in the hope that it will be useful, 13// but WITHOUT ANY WARRANTY; without even the implied warranty of 14// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15// GNU General Public License for more details. 16 17// Under Section 7 of GPL version 3, you are granted additional 18// permissions described in the GCC Runtime Library Exception, version 19// 3.1, as published by the Free Software Foundation. 20 21// You should have received a copy of the GNU General Public License and 22// a copy of the GCC Runtime Library Exception along with this program; 23// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 24// <http://www.gnu.org/licenses/>. 25 26/** @file bits/atomic_2.h 27 * This is an internal header file, included by other library headers. 28 * You should not attempt to use it directly. 29 */ 30 31#ifndef _GLIBCXX_ATOMIC_2_H 32#define _GLIBCXX_ATOMIC_2_H 1 33 34#pragma GCC system_header 35 36// _GLIBCXX_BEGIN_NAMESPACE(std) 37 38// 2 == __atomic2 == Always lock-free 39// Assumed: 40// _GLIBCXX_ATOMIC_BUILTINS_1 41// _GLIBCXX_ATOMIC_BUILTINS_2 42// _GLIBCXX_ATOMIC_BUILTINS_4 43// _GLIBCXX_ATOMIC_BUILTINS_8 44namespace __atomic2 45{ 46 /// atomic_flag 47 struct atomic_flag : public __atomic_flag_base 48 { 49 atomic_flag() = default; 50 ~atomic_flag() = default; 51 atomic_flag(const atomic_flag&) = delete; 52 atomic_flag& operator=(const atomic_flag&) volatile = delete; 53 54 // Conversion to ATOMIC_FLAG_INIT. 55 atomic_flag(bool __i): __atomic_flag_base({ __i }) { } 56 57 bool 58 test_and_set(memory_order __m = memory_order_seq_cst) 59 { 60 // Redundant synchronize if built-in for lock is a full barrier. 61 if (__m != memory_order_acquire && __m != memory_order_acq_rel) 62 __sync_synchronize(); 63 return __sync_lock_test_and_set(&_M_i, 1); 64 } 65 66 void 67 clear(memory_order __m = memory_order_seq_cst) 68 { 69 __glibcxx_assert(__m != memory_order_consume); 70 __glibcxx_assert(__m != memory_order_acquire); 71 __glibcxx_assert(__m != memory_order_acq_rel); 72 73 __sync_lock_release(&_M_i); 74 if (__m != memory_order_acquire && __m != memory_order_acq_rel) 75 __sync_synchronize(); 76 } 77 }; 78 79 80 /// 29.4.2, address types 81 struct atomic_address 82 { 83 private: 84 void* _M_i; 85 86 public: 87 atomic_address() = default; 88 ~atomic_address() = default; 89 atomic_address(const atomic_address&) = delete; 90 atomic_address& operator=(const atomic_address&) volatile = delete; 91 92 atomic_address(void* __v) { _M_i = __v; } 93 94 bool 95 is_lock_free() const 96 { return true; } 97 98 void 99 store(void* __v, memory_order __m = memory_order_seq_cst) 100 { 101 __glibcxx_assert(__m != memory_order_acquire); 102 __glibcxx_assert(__m != memory_order_acq_rel); 103 __glibcxx_assert(__m != memory_order_consume); 104 105 if (__m == memory_order_relaxed) 106 _M_i = __v; 107 else 108 { 109 // write_mem_barrier(); 110 _M_i = __v; 111 if (__m == memory_order_seq_cst) 112 __sync_synchronize(); 113 } 114 } 115 116 void* 117 load(memory_order __m = memory_order_seq_cst) const 118 { 119 __glibcxx_assert(__m != memory_order_release); 120 __glibcxx_assert(__m != memory_order_acq_rel); 121 122 __sync_synchronize(); 123 void* __ret = _M_i; 124 __sync_synchronize(); 125 return __ret; 126 } 127 128 void* 129 exchange(void* __v, memory_order __m = memory_order_seq_cst) 130 { 131 // XXX built-in assumes memory_order_acquire. 132 return __sync_lock_test_and_set(&_M_i, __v); 133 } 134 135 bool 136 compare_exchange_weak(void*& __v1, void* __v2, memory_order __m1, 137 memory_order __m2) 138 { return compare_exchange_strong(__v1, __v2, __m1, __m2); } 139 140 bool 141 compare_exchange_weak(void*& __v1, void* __v2, 142 memory_order __m = memory_order_seq_cst) 143 { 144 return compare_exchange_weak(__v1, __v2, __m, 145 __calculate_memory_order(__m)); 146 } 147 148 bool 149 compare_exchange_strong(void*& __v1, void* __v2, memory_order __m1, 150 memory_order __m2) 151 { 152 __glibcxx_assert(__m2 != memory_order_release); 153 __glibcxx_assert(__m2 != memory_order_acq_rel); 154 __glibcxx_assert(__m2 <= __m1); 155 156 void* __v1o = __v1; 157 void* __v1n = __sync_val_compare_and_swap(&_M_i, __v1o, __v2); 158 159 // Assume extra stores (of same value) allowed in true case. 160 __v1 = __v1n; 161 return __v1o == __v1n; 162 } 163 164 bool 165 compare_exchange_strong(void*& __v1, void* __v2, 166 memory_order __m = memory_order_seq_cst) 167 { 168 return compare_exchange_strong(__v1, __v2, __m, 169 __calculate_memory_order(__m)); 170 } 171 172 void* 173 fetch_add(ptrdiff_t __d, memory_order __m = memory_order_seq_cst) 174 { return __sync_fetch_and_add(&_M_i, __d); } 175 176 void* 177 fetch_sub(ptrdiff_t __d, memory_order __m = memory_order_seq_cst) 178 { return __sync_fetch_and_sub(&_M_i, __d); } 179 180 operator void*() const 181 { return load(); } 182 183 void* 184 operator=(void* __v) 185 { 186 store(__v); 187 return __v; 188 } 189 190 void* 191 operator+=(ptrdiff_t __d) 192 { return __sync_add_and_fetch(&_M_i, __d); } 193 194 void* 195 operator-=(ptrdiff_t __d) 196 { return __sync_sub_and_fetch(&_M_i, __d); } 197 }; 198 199 // 29.3.1 atomic integral types 200 // For each of the integral types, define atomic_[integral type] struct 201 // 202 // atomic_bool bool 203 // atomic_char char 204 // atomic_schar signed char 205 // atomic_uchar unsigned char 206 // atomic_short short 207 // atomic_ushort unsigned short 208 // atomic_int int 209 // atomic_uint unsigned int 210 // atomic_long long 211 // atomic_ulong unsigned long 212 // atomic_llong long long 213 // atomic_ullong unsigned long long 214 // atomic_char16_t char16_t 215 // atomic_char32_t char32_t 216 // atomic_wchar_t wchar_t 217 218 // Base type. 219 // NB: Assuming _ITp is an integral scalar type that is 1, 2, 4, or 8 bytes, 220 // since that is what GCC built-in functions for atomic memory access work on. 221 template<typename _ITp> 222 struct __atomic_base 223 { 224 private: 225 typedef _ITp __integral_type; 226 227 __integral_type _M_i; 228 229 public: 230 __atomic_base() = default; 231 ~__atomic_base() = default; 232 __atomic_base(const __atomic_base&) = delete; 233 __atomic_base& operator=(const __atomic_base&) volatile = delete; 234 235 // Requires __integral_type convertible to _M_base._M_i. 236 __atomic_base(__integral_type __i) { _M_i = __i; } 237 238 operator __integral_type() const 239 { return load(); } 240 241 __integral_type 242 operator=(__integral_type __i) 243 { 244 store(__i); 245 return __i; 246 } 247 248 __integral_type 249 operator++(int) 250 { return fetch_add(1); } 251 252 __integral_type 253 operator--(int) 254 { return fetch_sub(1); } 255 256 __integral_type 257 operator++() 258 { return __sync_add_and_fetch(&_M_i, 1); } 259 260 __integral_type 261 operator--() 262 { return __sync_sub_and_fetch(&_M_i, 1); } 263 264 __integral_type 265 operator+=(__integral_type __i) 266 { return __sync_add_and_fetch(&_M_i, __i); } 267 268 __integral_type 269 operator-=(__integral_type __i) 270 { return __sync_sub_and_fetch(&_M_i, __i); } 271 272 __integral_type 273 operator&=(__integral_type __i) 274 { return __sync_and_and_fetch(&_M_i, __i); } 275 276 __integral_type 277 operator|=(__integral_type __i) 278 { return __sync_or_and_fetch(&_M_i, __i); } 279 280 __integral_type 281 operator^=(__integral_type __i) 282 { return __sync_xor_and_fetch(&_M_i, __i); } 283 284 bool 285 is_lock_free() const 286 { return true; } 287 288 void 289 store(__integral_type __i, memory_order __m = memory_order_seq_cst) 290 { 291 __glibcxx_assert(__m != memory_order_acquire); 292 __glibcxx_assert(__m != memory_order_acq_rel); 293 __glibcxx_assert(__m != memory_order_consume); 294 295 if (__m == memory_order_relaxed) 296 _M_i = __i; 297 else 298 { 299 // write_mem_barrier(); 300 _M_i = __i; 301 if (__m == memory_order_seq_cst) 302 __sync_synchronize(); 303 } 304 } 305 306 __integral_type 307 load(memory_order __m = memory_order_seq_cst) const 308 { 309 __glibcxx_assert(__m != memory_order_release); 310 __glibcxx_assert(__m != memory_order_acq_rel); 311 312 __sync_synchronize(); 313 __integral_type __ret = _M_i; 314 __sync_synchronize(); 315 return __ret; 316 } 317 318 __integral_type 319 exchange(__integral_type __i, memory_order __m = memory_order_seq_cst) 320 { 321 // XXX built-in assumes memory_order_acquire. 322 return __sync_lock_test_and_set(&_M_i, __i); 323 } 324 325 bool 326 compare_exchange_weak(__integral_type& __i1, __integral_type __i2, 327 memory_order __m1, memory_order __m2) 328 { return compare_exchange_strong(__i1, __i2, __m1, __m2); } 329 330 bool 331 compare_exchange_weak(__integral_type& __i1, __integral_type __i2, 332 memory_order __m = memory_order_seq_cst) 333 { 334 return compare_exchange_weak(__i1, __i2, __m, 335 __calculate_memory_order(__m)); 336 } 337 338 bool 339 compare_exchange_strong(__integral_type& __i1, __integral_type __i2, 340 memory_order __m1, memory_order __m2) 341 { 342 __glibcxx_assert(__m2 != memory_order_release); 343 __glibcxx_assert(__m2 != memory_order_acq_rel); 344 __glibcxx_assert(__m2 <= __m1); 345 346 __integral_type __i1o = __i1; 347 __integral_type __i1n = __sync_val_compare_and_swap(&_M_i, __i1o, __i2); 348 349 // Assume extra stores (of same value) allowed in true case. 350 __i1 = __i1n; 351 return __i1o == __i1n; 352 } 353 354 bool 355 compare_exchange_strong(__integral_type& __i1, __integral_type __i2, 356 memory_order __m = memory_order_seq_cst) 357 { 358 return compare_exchange_strong(__i1, __i2, __m, 359 __calculate_memory_order(__m)); 360 } 361 362 __integral_type 363 fetch_add(__integral_type __i, 364 memory_order __m = memory_order_seq_cst) 365 { return __sync_fetch_and_add(&_M_i, __i); } 366 367 __integral_type 368 fetch_sub(__integral_type __i, 369 memory_order __m = memory_order_seq_cst) 370 { return __sync_fetch_and_sub(&_M_i, __i); } 371 372 __integral_type 373 fetch_and(__integral_type __i, 374 memory_order __m = memory_order_seq_cst) 375 { return __sync_fetch_and_and(&_M_i, __i); } 376 377 __integral_type 378 fetch_or(__integral_type __i, 379 memory_order __m = memory_order_seq_cst) 380 { return __sync_fetch_and_or(&_M_i, __i); } 381 382 __integral_type 383 fetch_xor(__integral_type __i, 384 memory_order __m = memory_order_seq_cst) 385 { return __sync_fetch_and_xor(&_M_i, __i); } 386 }; 387 388 389 /// atomic_bool 390 // NB: No operators or fetch-operations for this type. 391 struct atomic_bool 392 { 393 private: 394 __atomic_base<bool> _M_base; 395 396 public: 397 atomic_bool() = default; 398 ~atomic_bool() = default; 399 atomic_bool(const atomic_bool&) = delete; 400 atomic_bool& operator=(const atomic_bool&) volatile = delete; 401 402 atomic_bool(bool __i) : _M_base(__i) { } 403 404 bool 405 operator=(bool __i) 406 { return _M_base.operator=(__i); } 407 408 operator bool() const 409 { return _M_base.load(); } 410 411 bool 412 is_lock_free() const 413 { return _M_base.is_lock_free(); } 414 415 void 416 store(bool __i, memory_order __m = memory_order_seq_cst) 417 { _M_base.store(__i, __m); } 418 419 bool 420 load(memory_order __m = memory_order_seq_cst) const 421 { return _M_base.load(__m); } 422 423 bool 424 exchange(bool __i, memory_order __m = memory_order_seq_cst) 425 { return _M_base.exchange(__i, __m); } 426 427 bool 428 compare_exchange_weak(bool& __i1, bool __i2, memory_order __m1, 429 memory_order __m2) 430 { return _M_base.compare_exchange_weak(__i1, __i2, __m1, __m2); } 431 432 bool 433 compare_exchange_weak(bool& __i1, bool __i2, 434 memory_order __m = memory_order_seq_cst) 435 { return _M_base.compare_exchange_weak(__i1, __i2, __m); } 436 437 bool 438 compare_exchange_strong(bool& __i1, bool __i2, memory_order __m1, 439 memory_order __m2) 440 { return _M_base.compare_exchange_strong(__i1, __i2, __m1, __m2); } 441 442 443 bool 444 compare_exchange_strong(bool& __i1, bool __i2, 445 memory_order __m = memory_order_seq_cst) 446 { return _M_base.compare_exchange_strong(__i1, __i2, __m); } 447 }; 448} // namespace __atomic2 449 450// _GLIBCXX_END_NAMESPACE 451 452#endif 453