1//===-- tsan_interceptors_mac.cpp -----------------------------------------===// 2// 3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4// See https://llvm.org/LICENSE.txt for license information. 5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6// 7//===----------------------------------------------------------------------===// 8// 9// This file is a part of ThreadSanitizer (TSan), a race detector. 10// 11// Mac-specific interceptors. 12//===----------------------------------------------------------------------===// 13 14#include "sanitizer_common/sanitizer_platform.h" 15#if SANITIZER_APPLE 16 17#include "interception/interception.h" 18#include "tsan_interceptors.h" 19#include "tsan_interface.h" 20#include "tsan_interface_ann.h" 21#include "tsan_spinlock_defs_mac.h" 22#include "sanitizer_common/sanitizer_addrhashmap.h" 23 24#include <errno.h> 25#include <libkern/OSAtomic.h> 26#include <objc/objc-sync.h> 27#include <os/lock.h> 28#include <sys/ucontext.h> 29 30#if defined(__has_include) && __has_include(<xpc/xpc.h>) 31#include <xpc/xpc.h> 32#endif // #if defined(__has_include) && __has_include(<xpc/xpc.h>) 33 34typedef long long_t; 35 36extern "C" { 37int getcontext(ucontext_t *ucp) __attribute__((returns_twice)); 38int setcontext(const ucontext_t *ucp); 39} 40 41namespace __tsan { 42 43// The non-barrier versions of OSAtomic* functions are semantically mo_relaxed, 44// but the two variants (e.g. OSAtomicAdd32 and OSAtomicAdd32Barrier) are 45// actually aliases of each other, and we cannot have different interceptors for 46// them, because they're actually the same function. Thus, we have to stay 47// conservative and treat the non-barrier versions as mo_acq_rel. 48static constexpr morder kMacOrderBarrier = mo_acq_rel; 49static constexpr morder kMacOrderNonBarrier = mo_acq_rel; 50static constexpr morder kMacFailureOrder = mo_relaxed; 51 52#define OSATOMIC_INTERCEPTOR(return_t, t, tsan_t, f, tsan_atomic_f, mo) \ 53 TSAN_INTERCEPTOR(return_t, f, t x, volatile t *ptr) { \ 54 SCOPED_TSAN_INTERCEPTOR(f, x, ptr); \ 55 return tsan_atomic_f((volatile tsan_t *)ptr, x, mo); \ 56 } 57 58#define OSATOMIC_INTERCEPTOR_PLUS_X(return_t, t, tsan_t, f, tsan_atomic_f, mo) \ 59 TSAN_INTERCEPTOR(return_t, f, t x, volatile t *ptr) { \ 60 SCOPED_TSAN_INTERCEPTOR(f, x, ptr); \ 61 return tsan_atomic_f((volatile tsan_t *)ptr, x, mo) + x; \ 62 } 63 64#define OSATOMIC_INTERCEPTOR_PLUS_1(return_t, t, tsan_t, f, tsan_atomic_f, mo) \ 65 TSAN_INTERCEPTOR(return_t, f, volatile t *ptr) { \ 66 SCOPED_TSAN_INTERCEPTOR(f, ptr); \ 67 return tsan_atomic_f((volatile tsan_t *)ptr, 1, mo) + 1; \ 68 } 69 70#define OSATOMIC_INTERCEPTOR_MINUS_1(return_t, t, tsan_t, f, tsan_atomic_f, \ 71 mo) \ 72 TSAN_INTERCEPTOR(return_t, f, volatile t *ptr) { \ 73 SCOPED_TSAN_INTERCEPTOR(f, ptr); \ 74 return tsan_atomic_f((volatile tsan_t *)ptr, 1, mo) - 1; \ 75 } 76 77#define OSATOMIC_INTERCEPTORS_ARITHMETIC(f, tsan_atomic_f, m) \ 78 m(int32_t, int32_t, a32, f##32, __tsan_atomic32_##tsan_atomic_f, \ 79 kMacOrderNonBarrier) \ 80 m(int32_t, int32_t, a32, f##32##Barrier, __tsan_atomic32_##tsan_atomic_f, \ 81 kMacOrderBarrier) \ 82 m(int64_t, int64_t, a64, f##64, __tsan_atomic64_##tsan_atomic_f, \ 83 kMacOrderNonBarrier) \ 84 m(int64_t, int64_t, a64, f##64##Barrier, __tsan_atomic64_##tsan_atomic_f, \ 85 kMacOrderBarrier) 86 87#define OSATOMIC_INTERCEPTORS_BITWISE(f, tsan_atomic_f, m, m_orig) \ 88 m(int32_t, uint32_t, a32, f##32, __tsan_atomic32_##tsan_atomic_f, \ 89 kMacOrderNonBarrier) \ 90 m(int32_t, uint32_t, a32, f##32##Barrier, __tsan_atomic32_##tsan_atomic_f, \ 91 kMacOrderBarrier) \ 92 m_orig(int32_t, uint32_t, a32, f##32##Orig, __tsan_atomic32_##tsan_atomic_f, \ 93 kMacOrderNonBarrier) \ 94 m_orig(int32_t, uint32_t, a32, f##32##OrigBarrier, \ 95 __tsan_atomic32_##tsan_atomic_f, kMacOrderBarrier) 96 97OSATOMIC_INTERCEPTORS_ARITHMETIC(OSAtomicAdd, fetch_add, 98 OSATOMIC_INTERCEPTOR_PLUS_X) 99OSATOMIC_INTERCEPTORS_ARITHMETIC(OSAtomicIncrement, fetch_add, 100 OSATOMIC_INTERCEPTOR_PLUS_1) 101OSATOMIC_INTERCEPTORS_ARITHMETIC(OSAtomicDecrement, fetch_sub, 102 OSATOMIC_INTERCEPTOR_MINUS_1) 103OSATOMIC_INTERCEPTORS_BITWISE(OSAtomicOr, fetch_or, OSATOMIC_INTERCEPTOR_PLUS_X, 104 OSATOMIC_INTERCEPTOR) 105OSATOMIC_INTERCEPTORS_BITWISE(OSAtomicAnd, fetch_and, 106 OSATOMIC_INTERCEPTOR_PLUS_X, OSATOMIC_INTERCEPTOR) 107OSATOMIC_INTERCEPTORS_BITWISE(OSAtomicXor, fetch_xor, 108 OSATOMIC_INTERCEPTOR_PLUS_X, OSATOMIC_INTERCEPTOR) 109 110#define OSATOMIC_INTERCEPTORS_CAS(f, tsan_atomic_f, tsan_t, t) \ 111 TSAN_INTERCEPTOR(bool, f, t old_value, t new_value, t volatile *ptr) { \ 112 SCOPED_TSAN_INTERCEPTOR(f, old_value, new_value, ptr); \ 113 return tsan_atomic_f##_compare_exchange_strong( \ 114 (volatile tsan_t *)ptr, (tsan_t *)&old_value, (tsan_t)new_value, \ 115 kMacOrderNonBarrier, kMacFailureOrder); \ 116 } \ 117 \ 118 TSAN_INTERCEPTOR(bool, f##Barrier, t old_value, t new_value, \ 119 t volatile *ptr) { \ 120 SCOPED_TSAN_INTERCEPTOR(f##Barrier, old_value, new_value, ptr); \ 121 return tsan_atomic_f##_compare_exchange_strong( \ 122 (volatile tsan_t *)ptr, (tsan_t *)&old_value, (tsan_t)new_value, \ 123 kMacOrderBarrier, kMacFailureOrder); \ 124 } 125 126OSATOMIC_INTERCEPTORS_CAS(OSAtomicCompareAndSwapInt, __tsan_atomic32, a32, int) 127OSATOMIC_INTERCEPTORS_CAS(OSAtomicCompareAndSwapLong, __tsan_atomic64, a64, 128 long_t) 129OSATOMIC_INTERCEPTORS_CAS(OSAtomicCompareAndSwapPtr, __tsan_atomic64, a64, 130 void *) 131OSATOMIC_INTERCEPTORS_CAS(OSAtomicCompareAndSwap32, __tsan_atomic32, a32, 132 int32_t) 133OSATOMIC_INTERCEPTORS_CAS(OSAtomicCompareAndSwap64, __tsan_atomic64, a64, 134 int64_t) 135 136#define OSATOMIC_INTERCEPTOR_BITOP(f, op, clear, mo) \ 137 TSAN_INTERCEPTOR(bool, f, uint32_t n, volatile void *ptr) { \ 138 SCOPED_TSAN_INTERCEPTOR(f, n, ptr); \ 139 volatile char *byte_ptr = ((volatile char *)ptr) + (n >> 3); \ 140 char bit = 0x80u >> (n & 7); \ 141 char mask = clear ? ~bit : bit; \ 142 char orig_byte = op((volatile a8 *)byte_ptr, mask, mo); \ 143 return orig_byte & bit; \ 144 } 145 146#define OSATOMIC_INTERCEPTORS_BITOP(f, op, clear) \ 147 OSATOMIC_INTERCEPTOR_BITOP(f, op, clear, kMacOrderNonBarrier) \ 148 OSATOMIC_INTERCEPTOR_BITOP(f##Barrier, op, clear, kMacOrderBarrier) 149 150OSATOMIC_INTERCEPTORS_BITOP(OSAtomicTestAndSet, __tsan_atomic8_fetch_or, false) 151OSATOMIC_INTERCEPTORS_BITOP(OSAtomicTestAndClear, __tsan_atomic8_fetch_and, 152 true) 153 154TSAN_INTERCEPTOR(void, OSAtomicEnqueue, OSQueueHead *list, void *item, 155 size_t offset) { 156 SCOPED_TSAN_INTERCEPTOR(OSAtomicEnqueue, list, item, offset); 157 __tsan_release(item); 158 REAL(OSAtomicEnqueue)(list, item, offset); 159} 160 161TSAN_INTERCEPTOR(void *, OSAtomicDequeue, OSQueueHead *list, size_t offset) { 162 SCOPED_TSAN_INTERCEPTOR(OSAtomicDequeue, list, offset); 163 void *item = REAL(OSAtomicDequeue)(list, offset); 164 if (item) __tsan_acquire(item); 165 return item; 166} 167 168// OSAtomicFifoEnqueue and OSAtomicFifoDequeue are only on OS X. 169#if !SANITIZER_IOS 170 171TSAN_INTERCEPTOR(void, OSAtomicFifoEnqueue, OSFifoQueueHead *list, void *item, 172 size_t offset) { 173 SCOPED_TSAN_INTERCEPTOR(OSAtomicFifoEnqueue, list, item, offset); 174 __tsan_release(item); 175 REAL(OSAtomicFifoEnqueue)(list, item, offset); 176} 177 178TSAN_INTERCEPTOR(void *, OSAtomicFifoDequeue, OSFifoQueueHead *list, 179 size_t offset) { 180 SCOPED_TSAN_INTERCEPTOR(OSAtomicFifoDequeue, list, offset); 181 void *item = REAL(OSAtomicFifoDequeue)(list, offset); 182 if (item) __tsan_acquire(item); 183 return item; 184} 185 186#endif 187 188TSAN_INTERCEPTOR(void, OSSpinLockLock, volatile OSSpinLock *lock) { 189 CHECK(!cur_thread()->is_dead); 190 if (!cur_thread()->is_inited) { 191 return REAL(OSSpinLockLock)(lock); 192 } 193 SCOPED_TSAN_INTERCEPTOR(OSSpinLockLock, lock); 194 REAL(OSSpinLockLock)(lock); 195 Acquire(thr, pc, (uptr)lock); 196} 197 198TSAN_INTERCEPTOR(bool, OSSpinLockTry, volatile OSSpinLock *lock) { 199 CHECK(!cur_thread()->is_dead); 200 if (!cur_thread()->is_inited) { 201 return REAL(OSSpinLockTry)(lock); 202 } 203 SCOPED_TSAN_INTERCEPTOR(OSSpinLockTry, lock); 204 bool result = REAL(OSSpinLockTry)(lock); 205 if (result) 206 Acquire(thr, pc, (uptr)lock); 207 return result; 208} 209 210TSAN_INTERCEPTOR(void, OSSpinLockUnlock, volatile OSSpinLock *lock) { 211 CHECK(!cur_thread()->is_dead); 212 if (!cur_thread()->is_inited) { 213 return REAL(OSSpinLockUnlock)(lock); 214 } 215 SCOPED_TSAN_INTERCEPTOR(OSSpinLockUnlock, lock); 216 Release(thr, pc, (uptr)lock); 217 REAL(OSSpinLockUnlock)(lock); 218} 219 220TSAN_INTERCEPTOR(void, os_lock_lock, void *lock) { 221 CHECK(!cur_thread()->is_dead); 222 if (!cur_thread()->is_inited) { 223 return REAL(os_lock_lock)(lock); 224 } 225 SCOPED_TSAN_INTERCEPTOR(os_lock_lock, lock); 226 REAL(os_lock_lock)(lock); 227 Acquire(thr, pc, (uptr)lock); 228} 229 230TSAN_INTERCEPTOR(bool, os_lock_trylock, void *lock) { 231 CHECK(!cur_thread()->is_dead); 232 if (!cur_thread()->is_inited) { 233 return REAL(os_lock_trylock)(lock); 234 } 235 SCOPED_TSAN_INTERCEPTOR(os_lock_trylock, lock); 236 bool result = REAL(os_lock_trylock)(lock); 237 if (result) 238 Acquire(thr, pc, (uptr)lock); 239 return result; 240} 241 242TSAN_INTERCEPTOR(void, os_lock_unlock, void *lock) { 243 CHECK(!cur_thread()->is_dead); 244 if (!cur_thread()->is_inited) { 245 return REAL(os_lock_unlock)(lock); 246 } 247 SCOPED_TSAN_INTERCEPTOR(os_lock_unlock, lock); 248 Release(thr, pc, (uptr)lock); 249 REAL(os_lock_unlock)(lock); 250} 251 252TSAN_INTERCEPTOR(void, os_unfair_lock_lock, os_unfair_lock_t lock) { 253 if (!cur_thread()->is_inited || cur_thread()->is_dead) { 254 return REAL(os_unfair_lock_lock)(lock); 255 } 256 SCOPED_TSAN_INTERCEPTOR(os_unfair_lock_lock, lock); 257 REAL(os_unfair_lock_lock)(lock); 258 Acquire(thr, pc, (uptr)lock); 259} 260 261TSAN_INTERCEPTOR(void, os_unfair_lock_lock_with_options, os_unfair_lock_t lock, 262 u32 options) { 263 if (!cur_thread()->is_inited || cur_thread()->is_dead) { 264 return REAL(os_unfair_lock_lock_with_options)(lock, options); 265 } 266 SCOPED_TSAN_INTERCEPTOR(os_unfair_lock_lock_with_options, lock, options); 267 REAL(os_unfair_lock_lock_with_options)(lock, options); 268 Acquire(thr, pc, (uptr)lock); 269} 270 271TSAN_INTERCEPTOR(bool, os_unfair_lock_trylock, os_unfair_lock_t lock) { 272 if (!cur_thread()->is_inited || cur_thread()->is_dead) { 273 return REAL(os_unfair_lock_trylock)(lock); 274 } 275 SCOPED_TSAN_INTERCEPTOR(os_unfair_lock_trylock, lock); 276 bool result = REAL(os_unfair_lock_trylock)(lock); 277 if (result) 278 Acquire(thr, pc, (uptr)lock); 279 return result; 280} 281 282TSAN_INTERCEPTOR(void, os_unfair_lock_unlock, os_unfair_lock_t lock) { 283 if (!cur_thread()->is_inited || cur_thread()->is_dead) { 284 return REAL(os_unfair_lock_unlock)(lock); 285 } 286 SCOPED_TSAN_INTERCEPTOR(os_unfair_lock_unlock, lock); 287 Release(thr, pc, (uptr)lock); 288 REAL(os_unfair_lock_unlock)(lock); 289} 290 291#if defined(__has_include) && __has_include(<xpc/xpc.h>) 292 293TSAN_INTERCEPTOR(void, xpc_connection_set_event_handler, 294 xpc_connection_t connection, xpc_handler_t handler) { 295 SCOPED_TSAN_INTERCEPTOR(xpc_connection_set_event_handler, connection, 296 handler); 297 Release(thr, pc, (uptr)connection); 298 xpc_handler_t new_handler = ^(xpc_object_t object) { 299 { 300 SCOPED_INTERCEPTOR_RAW(xpc_connection_set_event_handler); 301 Acquire(thr, pc, (uptr)connection); 302 } 303 handler(object); 304 }; 305 REAL(xpc_connection_set_event_handler)(connection, new_handler); 306} 307 308TSAN_INTERCEPTOR(void, xpc_connection_send_barrier, xpc_connection_t connection, 309 dispatch_block_t barrier) { 310 SCOPED_TSAN_INTERCEPTOR(xpc_connection_send_barrier, connection, barrier); 311 Release(thr, pc, (uptr)connection); 312 dispatch_block_t new_barrier = ^() { 313 { 314 SCOPED_INTERCEPTOR_RAW(xpc_connection_send_barrier); 315 Acquire(thr, pc, (uptr)connection); 316 } 317 barrier(); 318 }; 319 REAL(xpc_connection_send_barrier)(connection, new_barrier); 320} 321 322TSAN_INTERCEPTOR(void, xpc_connection_send_message_with_reply, 323 xpc_connection_t connection, xpc_object_t message, 324 dispatch_queue_t replyq, xpc_handler_t handler) { 325 SCOPED_TSAN_INTERCEPTOR(xpc_connection_send_message_with_reply, connection, 326 message, replyq, handler); 327 Release(thr, pc, (uptr)connection); 328 xpc_handler_t new_handler = ^(xpc_object_t object) { 329 { 330 SCOPED_INTERCEPTOR_RAW(xpc_connection_send_message_with_reply); 331 Acquire(thr, pc, (uptr)connection); 332 } 333 handler(object); 334 }; 335 REAL(xpc_connection_send_message_with_reply) 336 (connection, message, replyq, new_handler); 337} 338 339TSAN_INTERCEPTOR(void, xpc_connection_cancel, xpc_connection_t connection) { 340 SCOPED_TSAN_INTERCEPTOR(xpc_connection_cancel, connection); 341 Release(thr, pc, (uptr)connection); 342 REAL(xpc_connection_cancel)(connection); 343} 344 345#endif // #if defined(__has_include) && __has_include(<xpc/xpc.h>) 346 347// Determines whether the Obj-C object pointer is a tagged pointer. Tagged 348// pointers encode the object data directly in their pointer bits and do not 349// have an associated memory allocation. The Obj-C runtime uses tagged pointers 350// to transparently optimize small objects. 351static bool IsTaggedObjCPointer(id obj) { 352 const uptr kPossibleTaggedBits = 0x8000000000000001ull; 353 return ((uptr)obj & kPossibleTaggedBits) != 0; 354} 355 356// Returns an address which can be used to inform TSan about synchronization 357// points (MutexLock/Unlock). The TSan infrastructure expects this to be a valid 358// address in the process space. We do a small allocation here to obtain a 359// stable address (the array backing the hash map can change). The memory is 360// never free'd (leaked) and allocation and locking are slow, but this code only 361// runs for @synchronized with tagged pointers, which is very rare. 362static uptr GetOrCreateSyncAddress(uptr addr, ThreadState *thr, uptr pc) { 363 typedef AddrHashMap<uptr, 5> Map; 364 static Map Addresses; 365 Map::Handle h(&Addresses, addr); 366 if (h.created()) { 367 ThreadIgnoreBegin(thr, pc); 368 *h = (uptr) user_alloc(thr, pc, /*size=*/1); 369 ThreadIgnoreEnd(thr); 370 } 371 return *h; 372} 373 374// Returns an address on which we can synchronize given an Obj-C object pointer. 375// For normal object pointers, this is just the address of the object in memory. 376// Tagged pointers are not backed by an actual memory allocation, so we need to 377// synthesize a valid address. 378static uptr SyncAddressForObjCObject(id obj, ThreadState *thr, uptr pc) { 379 if (IsTaggedObjCPointer(obj)) 380 return GetOrCreateSyncAddress((uptr)obj, thr, pc); 381 return (uptr)obj; 382} 383 384TSAN_INTERCEPTOR(int, objc_sync_enter, id obj) { 385 SCOPED_TSAN_INTERCEPTOR(objc_sync_enter, obj); 386 if (!obj) return REAL(objc_sync_enter)(obj); 387 uptr addr = SyncAddressForObjCObject(obj, thr, pc); 388 MutexPreLock(thr, pc, addr, MutexFlagWriteReentrant); 389 int result = REAL(objc_sync_enter)(obj); 390 CHECK_EQ(result, OBJC_SYNC_SUCCESS); 391 MutexPostLock(thr, pc, addr, MutexFlagWriteReentrant); 392 return result; 393} 394 395TSAN_INTERCEPTOR(int, objc_sync_exit, id obj) { 396 SCOPED_TSAN_INTERCEPTOR(objc_sync_exit, obj); 397 if (!obj) return REAL(objc_sync_exit)(obj); 398 uptr addr = SyncAddressForObjCObject(obj, thr, pc); 399 MutexUnlock(thr, pc, addr); 400 int result = REAL(objc_sync_exit)(obj); 401 if (result != OBJC_SYNC_SUCCESS) MutexInvalidAccess(thr, pc, addr); 402 return result; 403} 404 405TSAN_INTERCEPTOR(int, swapcontext, ucontext_t *oucp, const ucontext_t *ucp) { 406 { 407 SCOPED_INTERCEPTOR_RAW(swapcontext, oucp, ucp); 408 } 409 // Because of swapcontext() semantics we have no option but to copy its 410 // implementation here 411 if (!oucp || !ucp) { 412 errno = EINVAL; 413 return -1; 414 } 415 ThreadState *thr = cur_thread(); 416 const int UCF_SWAPPED = 0x80000000; 417 oucp->uc_onstack &= ~UCF_SWAPPED; 418 thr->ignore_interceptors++; 419 int ret = getcontext(oucp); 420 if (!(oucp->uc_onstack & UCF_SWAPPED)) { 421 thr->ignore_interceptors--; 422 if (!ret) { 423 oucp->uc_onstack |= UCF_SWAPPED; 424 ret = setcontext(ucp); 425 } 426 } 427 return ret; 428} 429 430// On macOS, libc++ is always linked dynamically, so intercepting works the 431// usual way. 432#define STDCXX_INTERCEPTOR TSAN_INTERCEPTOR 433 434namespace { 435struct fake_shared_weak_count { 436 volatile a64 shared_owners; 437 volatile a64 shared_weak_owners; 438 virtual void _unused_0x0() = 0; 439 virtual void _unused_0x8() = 0; 440 virtual void on_zero_shared() = 0; 441 virtual void _unused_0x18() = 0; 442 virtual void on_zero_shared_weak() = 0; 443 virtual ~fake_shared_weak_count() = 0; // suppress -Wnon-virtual-dtor 444}; 445} // namespace 446 447// The following code adds libc++ interceptors for: 448// void __shared_weak_count::__release_shared() _NOEXCEPT; 449// bool __shared_count::__release_shared() _NOEXCEPT; 450// Shared and weak pointers in C++ maintain reference counts via atomics in 451// libc++.dylib, which are TSan-invisible, and this leads to false positives in 452// destructor code. These interceptors re-implements the whole functions so that 453// the mo_acq_rel semantics of the atomic decrement are visible. 454// 455// Unfortunately, the interceptors cannot simply Acquire/Release some sync 456// object and call the original function, because it would have a race between 457// the sync and the destruction of the object. Calling both under a lock will 458// not work because the destructor can invoke this interceptor again (and even 459// in a different thread, so recursive locks don't help). 460 461STDCXX_INTERCEPTOR(void, _ZNSt3__119__shared_weak_count16__release_sharedEv, 462 fake_shared_weak_count *o) { 463 if (!flags()->shared_ptr_interceptor) 464 return REAL(_ZNSt3__119__shared_weak_count16__release_sharedEv)(o); 465 466 SCOPED_TSAN_INTERCEPTOR(_ZNSt3__119__shared_weak_count16__release_sharedEv, 467 o); 468 if (__tsan_atomic64_fetch_add(&o->shared_owners, -1, mo_release) == 0) { 469 Acquire(thr, pc, (uptr)&o->shared_owners); 470 o->on_zero_shared(); 471 if (__tsan_atomic64_fetch_add(&o->shared_weak_owners, -1, mo_release) == 472 0) { 473 Acquire(thr, pc, (uptr)&o->shared_weak_owners); 474 o->on_zero_shared_weak(); 475 } 476 } 477} 478 479STDCXX_INTERCEPTOR(bool, _ZNSt3__114__shared_count16__release_sharedEv, 480 fake_shared_weak_count *o) { 481 if (!flags()->shared_ptr_interceptor) 482 return REAL(_ZNSt3__114__shared_count16__release_sharedEv)(o); 483 484 SCOPED_TSAN_INTERCEPTOR(_ZNSt3__114__shared_count16__release_sharedEv, o); 485 if (__tsan_atomic64_fetch_add(&o->shared_owners, -1, mo_release) == 0) { 486 Acquire(thr, pc, (uptr)&o->shared_owners); 487 o->on_zero_shared(); 488 return true; 489 } 490 return false; 491} 492 493namespace { 494struct call_once_callback_args { 495 void (*orig_func)(void *arg); 496 void *orig_arg; 497 void *flag; 498}; 499 500void call_once_callback_wrapper(void *arg) { 501 call_once_callback_args *new_args = (call_once_callback_args *)arg; 502 new_args->orig_func(new_args->orig_arg); 503 __tsan_release(new_args->flag); 504} 505} // namespace 506 507// This adds a libc++ interceptor for: 508// void __call_once(volatile unsigned long&, void*, void(*)(void*)); 509// C++11 call_once is implemented via an internal function __call_once which is 510// inside libc++.dylib, and the atomic release store inside it is thus 511// TSan-invisible. To avoid false positives, this interceptor wraps the callback 512// function and performs an explicit Release after the user code has run. 513STDCXX_INTERCEPTOR(void, _ZNSt3__111__call_onceERVmPvPFvS2_E, void *flag, 514 void *arg, void (*func)(void *arg)) { 515 call_once_callback_args new_args = {func, arg, flag}; 516 REAL(_ZNSt3__111__call_onceERVmPvPFvS2_E)(flag, &new_args, 517 call_once_callback_wrapper); 518} 519 520} // namespace __tsan 521 522#endif // SANITIZER_APPLE 523