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 44 namespace __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&) = 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) volatile 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) volatile 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&) = delete; 91 92 atomic_address(void* __v) { _M_i = __v; } 93 94 bool 95 is_lock_free() const volatile 96 { return true; } 97 98 void 99 store(void* __v, memory_order __m = memory_order_seq_cst) volatile 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 volatile 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) volatile 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) volatile 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) volatile 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) volatile 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) volatile 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) volatile 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) volatile 178 { return __sync_fetch_and_sub(&_M_i, __d); } 179 180 operator void*() const volatile 181 { return load(); } 182 183 void* 184 operator=(void* __v) // XXX volatile 185 { 186 store(__v); 187 return __v; 188 } 189 190 void* 191 operator+=(ptrdiff_t __d) volatile 192 { return __sync_add_and_fetch(&_M_i, __d); } 193 194 void* 195 operator-=(ptrdiff_t __d) volatile 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&) = 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 volatile 239 { return load(); } 240 241 __integral_type 242 operator=(__integral_type __i) // XXX volatile 243 { 244 store(__i); 245 return __i; 246 } 247 248 __integral_type 249 operator++(int) volatile 250 { return fetch_add(1); } 251 252 __integral_type 253 operator--(int) volatile 254 { return fetch_sub(1); } 255 256 __integral_type 257 operator++() volatile 258 { return __sync_add_and_fetch(&_M_i, 1); } 259 260 __integral_type 261 operator--() volatile 262 { return __sync_sub_and_fetch(&_M_i, 1); } 263 264 __integral_type 265 operator+=(__integral_type __i) volatile 266 { return __sync_add_and_fetch(&_M_i, __i); } 267 268 __integral_type 269 operator-=(__integral_type __i) volatile 270 { return __sync_sub_and_fetch(&_M_i, __i); } 271 272 __integral_type 273 operator&=(__integral_type __i) volatile 274 { return __sync_and_and_fetch(&_M_i, __i); } 275 276 __integral_type 277 operator|=(__integral_type __i) volatile 278 { return __sync_or_and_fetch(&_M_i, __i); } 279 280 __integral_type 281 operator^=(__integral_type __i) volatile 282 { return __sync_xor_and_fetch(&_M_i, __i); } 283 284 bool 285 is_lock_free() const volatile 286 { return true; } 287 288 void 289 store(__integral_type __i, 290 memory_order __m = memory_order_seq_cst) volatile 291 { 292 __glibcxx_assert(__m != memory_order_acquire); 293 __glibcxx_assert(__m != memory_order_acq_rel); 294 __glibcxx_assert(__m != memory_order_consume); 295 296 if (__m == memory_order_relaxed) 297 _M_i = __i; 298 else 299 { 300 // write_mem_barrier(); 301 _M_i = __i; 302 if (__m == memory_order_seq_cst) 303 __sync_synchronize(); 304 } 305 } 306 307 __integral_type 308 load(memory_order __m = memory_order_seq_cst) const volatile 309 { 310 __glibcxx_assert(__m != memory_order_release); 311 __glibcxx_assert(__m != memory_order_acq_rel); 312 313 __sync_synchronize(); 314 __integral_type __ret = _M_i; 315 __sync_synchronize(); 316 return __ret; 317 } 318 319 __integral_type 320 exchange(__integral_type __i, 321 memory_order __m = memory_order_seq_cst) volatile 322 { 323 // XXX built-in assumes memory_order_acquire. 324 return __sync_lock_test_and_set(&_M_i, __i); 325 } 326 327 bool 328 compare_exchange_weak(__integral_type& __i1, __integral_type __i2, 329 memory_order __m1, memory_order __m2) volatile 330 { return compare_exchange_strong(__i1, __i2, __m1, __m2); } 331 332 bool 333 compare_exchange_weak(__integral_type& __i1, __integral_type __i2, 334 memory_order __m = memory_order_seq_cst) volatile 335 { 336 return compare_exchange_weak(__i1, __i2, __m, 337 __calculate_memory_order(__m)); 338 } 339 340 bool 341 compare_exchange_strong(__integral_type& __i1, __integral_type __i2, 342 memory_order __m1, memory_order __m2) volatile 343 { 344 __glibcxx_assert(__m2 != memory_order_release); 345 __glibcxx_assert(__m2 != memory_order_acq_rel); 346 __glibcxx_assert(__m2 <= __m1); 347 348 __integral_type __i1o = __i1; 349 __integral_type __i1n = __sync_val_compare_and_swap(&_M_i, __i1o, __i2); 350 351 // Assume extra stores (of same value) allowed in true case. 352 __i1 = __i1n; 353 return __i1o == __i1n; 354 } 355 356 bool 357 compare_exchange_strong(__integral_type& __i1, __integral_type __i2, 358 memory_order __m = memory_order_seq_cst) volatile 359 { 360 return compare_exchange_strong(__i1, __i2, __m, 361 __calculate_memory_order(__m)); 362 } 363 364 __integral_type 365 fetch_add(__integral_type __i, 366 memory_order __m = memory_order_seq_cst) volatile 367 { return __sync_fetch_and_add(&_M_i, __i); } 368 369 __integral_type 370 fetch_sub(__integral_type __i, 371 memory_order __m = memory_order_seq_cst) volatile 372 { return __sync_fetch_and_sub(&_M_i, __i); } 373 374 __integral_type 375 fetch_and(__integral_type __i, 376 memory_order __m = memory_order_seq_cst) volatile 377 { return __sync_fetch_and_and(&_M_i, __i); } 378 379 __integral_type 380 fetch_or(__integral_type __i, 381 memory_order __m = memory_order_seq_cst) volatile 382 { return __sync_fetch_and_or(&_M_i, __i); } 383 384 __integral_type 385 fetch_xor(__integral_type __i, 386 memory_order __m = memory_order_seq_cst) volatile 387 { return __sync_fetch_and_xor(&_M_i, __i); } 388 }; 389 390 391 /// atomic_bool 392 // NB: No operators or fetch-operations for this type. 393 struct atomic_bool 394 { 395 private: 396 __atomic_base<bool> _M_base; 397 398 public: 399 atomic_bool() = default; 400 ~atomic_bool() = default; 401 atomic_bool(const atomic_bool&) = delete; 402 atomic_bool& operator=(const atomic_bool&) = delete; 403 404 atomic_bool(bool __i) : _M_base(__i) { } 405 406 bool 407 operator=(bool __i) // XXX volatile 408 { return _M_base.operator=(__i); } 409 410 operator bool() const volatile 411 { return _M_base.load(); } 412 413 bool 414 is_lock_free() const volatile 415 { return _M_base.is_lock_free(); } 416 417 void 418 store(bool __i, memory_order __m = memory_order_seq_cst) volatile 419 { _M_base.store(__i, __m); } 420 421 bool 422 load(memory_order __m = memory_order_seq_cst) const volatile 423 { return _M_base.load(__m); } 424 425 bool 426 exchange(bool __i, memory_order __m = memory_order_seq_cst) volatile 427 { return _M_base.exchange(__i, __m); } 428 429 bool 430 compare_exchange_weak(bool& __i1, bool __i2, memory_order __m1, 431 memory_order __m2) volatile 432 { return _M_base.compare_exchange_weak(__i1, __i2, __m1, __m2); } 433 434 bool 435 compare_exchange_weak(bool& __i1, bool __i2, 436 memory_order __m = memory_order_seq_cst) volatile 437 { return _M_base.compare_exchange_weak(__i1, __i2, __m); } 438 439 bool 440 compare_exchange_strong(bool& __i1, bool __i2, memory_order __m1, 441 memory_order __m2) volatile 442 { return _M_base.compare_exchange_strong(__i1, __i2, __m1, __m2); } 443 444 445 bool 446 compare_exchange_strong(bool& __i1, bool __i2, 447 memory_order __m = memory_order_seq_cst) volatile 448 { return _M_base.compare_exchange_strong(__i1, __i2, __m); } 449 }; 450 } // namespace __atomic2 451 452 // _GLIBCXX_END_NAMESPACE 453 454 #endif 455
