1 //===-- tsan_interceptors_mac.cpp -----------------------------------------===//
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
7 //===----------------------------------------------------------------------===//
9 // This file is a part of ThreadSanitizer (TSan), a race detector.
11 // Mac-specific interceptors.
12 //===----------------------------------------------------------------------===//
14 #include "sanitizer_common/sanitizer_platform.h"
17 #include "interception/interception.h"
18 #include "tsan_interceptors.h"
19 #include "tsan_interface.h"
20 #include "tsan_interface_ann.h"
21 #include "sanitizer_common/sanitizer_addrhashmap.h"
24 #include <libkern/OSAtomic.h>
25 #include <objc/objc-sync.h>
27 #include <sys/ucontext.h>
29 #if defined(__has_include) && __has_include(<xpc/xpc.h>)
31 #endif // #if defined(__has_include) && __has_include(<xpc/xpc.h>)
36 int getcontext(ucontext_t
*ucp
) __attribute__((returns_twice
));
37 int setcontext(const ucontext_t
*ucp
);
42 // The non-barrier versions of OSAtomic* functions are semantically mo_relaxed,
43 // but the two variants (e.g. OSAtomicAdd32 and OSAtomicAdd32Barrier) are
44 // actually aliases of each other, and we cannot have different interceptors for
45 // them, because they're actually the same function. Thus, we have to stay
46 // conservative and treat the non-barrier versions as mo_acq_rel.
47 static const morder kMacOrderBarrier
= mo_acq_rel
;
48 static const morder kMacOrderNonBarrier
= mo_acq_rel
;
50 #define OSATOMIC_INTERCEPTOR(return_t, t, tsan_t, f, tsan_atomic_f, mo) \
51 TSAN_INTERCEPTOR(return_t, f, t x, volatile t *ptr) { \
52 SCOPED_TSAN_INTERCEPTOR(f, x, ptr); \
53 return tsan_atomic_f((volatile tsan_t *)ptr, x, mo); \
56 #define OSATOMIC_INTERCEPTOR_PLUS_X(return_t, t, tsan_t, f, tsan_atomic_f, mo) \
57 TSAN_INTERCEPTOR(return_t, f, t x, volatile t *ptr) { \
58 SCOPED_TSAN_INTERCEPTOR(f, x, ptr); \
59 return tsan_atomic_f((volatile tsan_t *)ptr, x, mo) + x; \
62 #define OSATOMIC_INTERCEPTOR_PLUS_1(return_t, t, tsan_t, f, tsan_atomic_f, mo) \
63 TSAN_INTERCEPTOR(return_t, f, volatile t *ptr) { \
64 SCOPED_TSAN_INTERCEPTOR(f, ptr); \
65 return tsan_atomic_f((volatile tsan_t *)ptr, 1, mo) + 1; \
68 #define OSATOMIC_INTERCEPTOR_MINUS_1(return_t, t, tsan_t, f, tsan_atomic_f, \
70 TSAN_INTERCEPTOR(return_t, f, volatile t *ptr) { \
71 SCOPED_TSAN_INTERCEPTOR(f, ptr); \
72 return tsan_atomic_f((volatile tsan_t *)ptr, 1, mo) - 1; \
75 #define OSATOMIC_INTERCEPTORS_ARITHMETIC(f, tsan_atomic_f, m) \
76 m(int32_t, int32_t, a32, f##32, __tsan_atomic32_##tsan_atomic_f, \
77 kMacOrderNonBarrier) \
78 m(int32_t, int32_t, a32, f##32##Barrier, __tsan_atomic32_##tsan_atomic_f, \
80 m(int64_t, int64_t, a64, f##64, __tsan_atomic64_##tsan_atomic_f, \
81 kMacOrderNonBarrier) \
82 m(int64_t, int64_t, a64, f##64##Barrier, __tsan_atomic64_##tsan_atomic_f, \
85 #define OSATOMIC_INTERCEPTORS_BITWISE(f, tsan_atomic_f, m, m_orig) \
86 m(int32_t, uint32_t, a32, f##32, __tsan_atomic32_##tsan_atomic_f, \
87 kMacOrderNonBarrier) \
88 m(int32_t, uint32_t, a32, f##32##Barrier, __tsan_atomic32_##tsan_atomic_f, \
90 m_orig(int32_t, uint32_t, a32, f##32##Orig, __tsan_atomic32_##tsan_atomic_f, \
91 kMacOrderNonBarrier) \
92 m_orig(int32_t, uint32_t, a32, f##32##OrigBarrier, \
93 __tsan_atomic32_##tsan_atomic_f, kMacOrderBarrier)
95 OSATOMIC_INTERCEPTORS_ARITHMETIC(OSAtomicAdd
, fetch_add
,
96 OSATOMIC_INTERCEPTOR_PLUS_X
)
97 OSATOMIC_INTERCEPTORS_ARITHMETIC(OSAtomicIncrement
, fetch_add
,
98 OSATOMIC_INTERCEPTOR_PLUS_1
)
99 OSATOMIC_INTERCEPTORS_ARITHMETIC(OSAtomicDecrement
, fetch_sub
,
100 OSATOMIC_INTERCEPTOR_MINUS_1
)
101 OSATOMIC_INTERCEPTORS_BITWISE(OSAtomicOr
, fetch_or
, OSATOMIC_INTERCEPTOR_PLUS_X
,
102 OSATOMIC_INTERCEPTOR
)
103 OSATOMIC_INTERCEPTORS_BITWISE(OSAtomicAnd
, fetch_and
,
104 OSATOMIC_INTERCEPTOR_PLUS_X
, OSATOMIC_INTERCEPTOR
)
105 OSATOMIC_INTERCEPTORS_BITWISE(OSAtomicXor
, fetch_xor
,
106 OSATOMIC_INTERCEPTOR_PLUS_X
, OSATOMIC_INTERCEPTOR
)
108 #define OSATOMIC_INTERCEPTORS_CAS(f, tsan_atomic_f, tsan_t, t) \
109 TSAN_INTERCEPTOR(bool, f, t old_value, t new_value, t volatile *ptr) { \
110 SCOPED_TSAN_INTERCEPTOR(f, old_value, new_value, ptr); \
111 return tsan_atomic_f##_compare_exchange_strong( \
112 (volatile tsan_t *)ptr, (tsan_t *)&old_value, (tsan_t)new_value, \
113 kMacOrderNonBarrier, kMacOrderNonBarrier); \
116 TSAN_INTERCEPTOR(bool, f##Barrier, t old_value, t new_value, \
118 SCOPED_TSAN_INTERCEPTOR(f##Barrier, old_value, new_value, ptr); \
119 return tsan_atomic_f##_compare_exchange_strong( \
120 (volatile tsan_t *)ptr, (tsan_t *)&old_value, (tsan_t)new_value, \
121 kMacOrderBarrier, kMacOrderNonBarrier); \
124 OSATOMIC_INTERCEPTORS_CAS(OSAtomicCompareAndSwapInt
, __tsan_atomic32
, a32
, int)
125 OSATOMIC_INTERCEPTORS_CAS(OSAtomicCompareAndSwapLong
, __tsan_atomic64
, a64
,
127 OSATOMIC_INTERCEPTORS_CAS(OSAtomicCompareAndSwapPtr
, __tsan_atomic64
, a64
,
129 OSATOMIC_INTERCEPTORS_CAS(OSAtomicCompareAndSwap32
, __tsan_atomic32
, a32
,
131 OSATOMIC_INTERCEPTORS_CAS(OSAtomicCompareAndSwap64
, __tsan_atomic64
, a64
,
134 #define OSATOMIC_INTERCEPTOR_BITOP(f, op, clear, mo) \
135 TSAN_INTERCEPTOR(bool, f, uint32_t n, volatile void *ptr) { \
136 SCOPED_TSAN_INTERCEPTOR(f, n, ptr); \
137 volatile char *byte_ptr = ((volatile char *)ptr) + (n >> 3); \
138 char bit = 0x80u >> (n & 7); \
139 char mask = clear ? ~bit : bit; \
140 char orig_byte = op((volatile a8 *)byte_ptr, mask, mo); \
141 return orig_byte & bit; \
144 #define OSATOMIC_INTERCEPTORS_BITOP(f, op, clear) \
145 OSATOMIC_INTERCEPTOR_BITOP(f, op, clear, kMacOrderNonBarrier) \
146 OSATOMIC_INTERCEPTOR_BITOP(f##Barrier, op, clear, kMacOrderBarrier)
148 OSATOMIC_INTERCEPTORS_BITOP(OSAtomicTestAndSet
, __tsan_atomic8_fetch_or
, false)
149 OSATOMIC_INTERCEPTORS_BITOP(OSAtomicTestAndClear
, __tsan_atomic8_fetch_and
,
152 TSAN_INTERCEPTOR(void, OSAtomicEnqueue
, OSQueueHead
*list
, void *item
,
154 SCOPED_TSAN_INTERCEPTOR(OSAtomicEnqueue
, list
, item
, offset
);
155 __tsan_release(item
);
156 REAL(OSAtomicEnqueue
)(list
, item
, offset
);
159 TSAN_INTERCEPTOR(void *, OSAtomicDequeue
, OSQueueHead
*list
, size_t offset
) {
160 SCOPED_TSAN_INTERCEPTOR(OSAtomicDequeue
, list
, offset
);
161 void *item
= REAL(OSAtomicDequeue
)(list
, offset
);
162 if (item
) __tsan_acquire(item
);
166 // OSAtomicFifoEnqueue and OSAtomicFifoDequeue are only on OS X.
169 TSAN_INTERCEPTOR(void, OSAtomicFifoEnqueue
, OSFifoQueueHead
*list
, void *item
,
171 SCOPED_TSAN_INTERCEPTOR(OSAtomicFifoEnqueue
, list
, item
, offset
);
172 __tsan_release(item
);
173 REAL(OSAtomicFifoEnqueue
)(list
, item
, offset
);
176 TSAN_INTERCEPTOR(void *, OSAtomicFifoDequeue
, OSFifoQueueHead
*list
,
178 SCOPED_TSAN_INTERCEPTOR(OSAtomicFifoDequeue
, list
, offset
);
179 void *item
= REAL(OSAtomicFifoDequeue
)(list
, offset
);
180 if (item
) __tsan_acquire(item
);
186 TSAN_INTERCEPTOR(void, OSSpinLockLock
, volatile OSSpinLock
*lock
) {
187 CHECK(!cur_thread()->is_dead
);
188 if (!cur_thread()->is_inited
) {
189 return REAL(OSSpinLockLock
)(lock
);
191 SCOPED_TSAN_INTERCEPTOR(OSSpinLockLock
, lock
);
192 REAL(OSSpinLockLock
)(lock
);
193 Acquire(thr
, pc
, (uptr
)lock
);
196 TSAN_INTERCEPTOR(bool, OSSpinLockTry
, volatile OSSpinLock
*lock
) {
197 CHECK(!cur_thread()->is_dead
);
198 if (!cur_thread()->is_inited
) {
199 return REAL(OSSpinLockTry
)(lock
);
201 SCOPED_TSAN_INTERCEPTOR(OSSpinLockTry
, lock
);
202 bool result
= REAL(OSSpinLockTry
)(lock
);
204 Acquire(thr
, pc
, (uptr
)lock
);
208 TSAN_INTERCEPTOR(void, OSSpinLockUnlock
, volatile OSSpinLock
*lock
) {
209 CHECK(!cur_thread()->is_dead
);
210 if (!cur_thread()->is_inited
) {
211 return REAL(OSSpinLockUnlock
)(lock
);
213 SCOPED_TSAN_INTERCEPTOR(OSSpinLockUnlock
, lock
);
214 Release(thr
, pc
, (uptr
)lock
);
215 REAL(OSSpinLockUnlock
)(lock
);
218 TSAN_INTERCEPTOR(void, os_lock_lock
, void *lock
) {
219 CHECK(!cur_thread()->is_dead
);
220 if (!cur_thread()->is_inited
) {
221 return REAL(os_lock_lock
)(lock
);
223 SCOPED_TSAN_INTERCEPTOR(os_lock_lock
, lock
);
224 REAL(os_lock_lock
)(lock
);
225 Acquire(thr
, pc
, (uptr
)lock
);
228 TSAN_INTERCEPTOR(bool, os_lock_trylock
, void *lock
) {
229 CHECK(!cur_thread()->is_dead
);
230 if (!cur_thread()->is_inited
) {
231 return REAL(os_lock_trylock
)(lock
);
233 SCOPED_TSAN_INTERCEPTOR(os_lock_trylock
, lock
);
234 bool result
= REAL(os_lock_trylock
)(lock
);
236 Acquire(thr
, pc
, (uptr
)lock
);
240 TSAN_INTERCEPTOR(void, os_lock_unlock
, void *lock
) {
241 CHECK(!cur_thread()->is_dead
);
242 if (!cur_thread()->is_inited
) {
243 return REAL(os_lock_unlock
)(lock
);
245 SCOPED_TSAN_INTERCEPTOR(os_lock_unlock
, lock
);
246 Release(thr
, pc
, (uptr
)lock
);
247 REAL(os_lock_unlock
)(lock
);
250 TSAN_INTERCEPTOR(void, os_unfair_lock_lock
, os_unfair_lock_t lock
) {
251 if (!cur_thread()->is_inited
|| cur_thread()->is_dead
) {
252 return REAL(os_unfair_lock_lock
)(lock
);
254 SCOPED_TSAN_INTERCEPTOR(os_unfair_lock_lock
, lock
);
255 REAL(os_unfair_lock_lock
)(lock
);
256 Acquire(thr
, pc
, (uptr
)lock
);
259 TSAN_INTERCEPTOR(void, os_unfair_lock_lock_with_options
, os_unfair_lock_t lock
,
261 if (!cur_thread()->is_inited
|| cur_thread()->is_dead
) {
262 return REAL(os_unfair_lock_lock_with_options
)(lock
, options
);
264 SCOPED_TSAN_INTERCEPTOR(os_unfair_lock_lock_with_options
, lock
, options
);
265 REAL(os_unfair_lock_lock_with_options
)(lock
, options
);
266 Acquire(thr
, pc
, (uptr
)lock
);
269 TSAN_INTERCEPTOR(bool, os_unfair_lock_trylock
, os_unfair_lock_t lock
) {
270 if (!cur_thread()->is_inited
|| cur_thread()->is_dead
) {
271 return REAL(os_unfair_lock_trylock
)(lock
);
273 SCOPED_TSAN_INTERCEPTOR(os_unfair_lock_trylock
, lock
);
274 bool result
= REAL(os_unfair_lock_trylock
)(lock
);
276 Acquire(thr
, pc
, (uptr
)lock
);
280 TSAN_INTERCEPTOR(void, os_unfair_lock_unlock
, os_unfair_lock_t lock
) {
281 if (!cur_thread()->is_inited
|| cur_thread()->is_dead
) {
282 return REAL(os_unfair_lock_unlock
)(lock
);
284 SCOPED_TSAN_INTERCEPTOR(os_unfair_lock_unlock
, lock
);
285 Release(thr
, pc
, (uptr
)lock
);
286 REAL(os_unfair_lock_unlock
)(lock
);
289 #if defined(__has_include) && __has_include(<xpc/xpc.h>)
291 TSAN_INTERCEPTOR(void, xpc_connection_set_event_handler
,
292 xpc_connection_t connection
, xpc_handler_t handler
) {
293 SCOPED_TSAN_INTERCEPTOR(xpc_connection_set_event_handler
, connection
,
295 Release(thr
, pc
, (uptr
)connection
);
296 xpc_handler_t new_handler
= ^(xpc_object_t object
) {
298 SCOPED_INTERCEPTOR_RAW(xpc_connection_set_event_handler
);
299 Acquire(thr
, pc
, (uptr
)connection
);
303 REAL(xpc_connection_set_event_handler
)(connection
, new_handler
);
306 TSAN_INTERCEPTOR(void, xpc_connection_send_barrier
, xpc_connection_t connection
,
307 dispatch_block_t barrier
) {
308 SCOPED_TSAN_INTERCEPTOR(xpc_connection_send_barrier
, connection
, barrier
);
309 Release(thr
, pc
, (uptr
)connection
);
310 dispatch_block_t new_barrier
= ^() {
312 SCOPED_INTERCEPTOR_RAW(xpc_connection_send_barrier
);
313 Acquire(thr
, pc
, (uptr
)connection
);
317 REAL(xpc_connection_send_barrier
)(connection
, new_barrier
);
320 TSAN_INTERCEPTOR(void, xpc_connection_send_message_with_reply
,
321 xpc_connection_t connection
, xpc_object_t message
,
322 dispatch_queue_t replyq
, xpc_handler_t handler
) {
323 SCOPED_TSAN_INTERCEPTOR(xpc_connection_send_message_with_reply
, connection
,
324 message
, replyq
, handler
);
325 Release(thr
, pc
, (uptr
)connection
);
326 xpc_handler_t new_handler
= ^(xpc_object_t object
) {
328 SCOPED_INTERCEPTOR_RAW(xpc_connection_send_message_with_reply
);
329 Acquire(thr
, pc
, (uptr
)connection
);
333 REAL(xpc_connection_send_message_with_reply
)
334 (connection
, message
, replyq
, new_handler
);
337 TSAN_INTERCEPTOR(void, xpc_connection_cancel
, xpc_connection_t connection
) {
338 SCOPED_TSAN_INTERCEPTOR(xpc_connection_cancel
, connection
);
339 Release(thr
, pc
, (uptr
)connection
);
340 REAL(xpc_connection_cancel
)(connection
);
343 #endif // #if defined(__has_include) && __has_include(<xpc/xpc.h>)
345 // Determines whether the Obj-C object pointer is a tagged pointer. Tagged
346 // pointers encode the object data directly in their pointer bits and do not
347 // have an associated memory allocation. The Obj-C runtime uses tagged pointers
348 // to transparently optimize small objects.
349 static bool IsTaggedObjCPointer(id obj
) {
350 const uptr kPossibleTaggedBits
= 0x8000000000000001ull
;
351 return ((uptr
)obj
& kPossibleTaggedBits
) != 0;
354 // Returns an address which can be used to inform TSan about synchronization
355 // points (MutexLock/Unlock). The TSan infrastructure expects this to be a valid
356 // address in the process space. We do a small allocation here to obtain a
357 // stable address (the array backing the hash map can change). The memory is
358 // never free'd (leaked) and allocation and locking are slow, but this code only
359 // runs for @synchronized with tagged pointers, which is very rare.
360 static uptr
GetOrCreateSyncAddress(uptr addr
, ThreadState
*thr
, uptr pc
) {
361 typedef AddrHashMap
<uptr
, 5> Map
;
362 static Map Addresses
;
363 Map::Handle
h(&Addresses
, addr
);
365 ThreadIgnoreBegin(thr
, pc
);
366 *h
= (uptr
) user_alloc(thr
, pc
, /*size=*/1);
367 ThreadIgnoreEnd(thr
, pc
);
372 // Returns an address on which we can synchronize given an Obj-C object pointer.
373 // For normal object pointers, this is just the address of the object in memory.
374 // Tagged pointers are not backed by an actual memory allocation, so we need to
375 // synthesize a valid address.
376 static uptr
SyncAddressForObjCObject(id obj
, ThreadState
*thr
, uptr pc
) {
377 if (IsTaggedObjCPointer(obj
))
378 return GetOrCreateSyncAddress((uptr
)obj
, thr
, pc
);
382 TSAN_INTERCEPTOR(int, objc_sync_enter
, id obj
) {
383 SCOPED_TSAN_INTERCEPTOR(objc_sync_enter
, obj
);
384 if (!obj
) return REAL(objc_sync_enter
)(obj
);
385 uptr addr
= SyncAddressForObjCObject(obj
, thr
, pc
);
386 MutexPreLock(thr
, pc
, addr
, MutexFlagWriteReentrant
);
387 int result
= REAL(objc_sync_enter
)(obj
);
388 CHECK_EQ(result
, OBJC_SYNC_SUCCESS
);
389 MutexPostLock(thr
, pc
, addr
, MutexFlagWriteReentrant
);
393 TSAN_INTERCEPTOR(int, objc_sync_exit
, id obj
) {
394 SCOPED_TSAN_INTERCEPTOR(objc_sync_exit
, obj
);
395 if (!obj
) return REAL(objc_sync_exit
)(obj
);
396 uptr addr
= SyncAddressForObjCObject(obj
, thr
, pc
);
397 MutexUnlock(thr
, pc
, addr
);
398 int result
= REAL(objc_sync_exit
)(obj
);
399 if (result
!= OBJC_SYNC_SUCCESS
) MutexInvalidAccess(thr
, pc
, addr
);
403 TSAN_INTERCEPTOR(int, swapcontext
, ucontext_t
*oucp
, const ucontext_t
*ucp
) {
405 SCOPED_INTERCEPTOR_RAW(swapcontext
, oucp
, ucp
);
407 // Bacause of swapcontext() semantics we have no option but to copy its
408 // impementation here
413 ThreadState
*thr
= cur_thread();
414 const int UCF_SWAPPED
= 0x80000000;
415 oucp
->uc_onstack
&= ~UCF_SWAPPED
;
416 thr
->ignore_interceptors
++;
417 int ret
= getcontext(oucp
);
418 if (!(oucp
->uc_onstack
& UCF_SWAPPED
)) {
419 thr
->ignore_interceptors
--;
421 oucp
->uc_onstack
|= UCF_SWAPPED
;
422 ret
= setcontext(ucp
);
428 // On macOS, libc++ is always linked dynamically, so intercepting works the
430 #define STDCXX_INTERCEPTOR TSAN_INTERCEPTOR
433 struct fake_shared_weak_count
{
434 volatile a64 shared_owners
;
435 volatile a64 shared_weak_owners
;
436 virtual void _unused_0x0() = 0;
437 virtual void _unused_0x8() = 0;
438 virtual void on_zero_shared() = 0;
439 virtual void _unused_0x18() = 0;
440 virtual void on_zero_shared_weak() = 0;
444 // The following code adds libc++ interceptors for:
445 // void __shared_weak_count::__release_shared() _NOEXCEPT;
446 // bool __shared_count::__release_shared() _NOEXCEPT;
447 // Shared and weak pointers in C++ maintain reference counts via atomics in
448 // libc++.dylib, which are TSan-invisible, and this leads to false positives in
449 // destructor code. These interceptors re-implements the whole functions so that
450 // the mo_acq_rel semantics of the atomic decrement are visible.
452 // Unfortunately, the interceptors cannot simply Acquire/Release some sync
453 // object and call the original function, because it would have a race between
454 // the sync and the destruction of the object. Calling both under a lock will
455 // not work because the destructor can invoke this interceptor again (and even
456 // in a different thread, so recursive locks don't help).
458 STDCXX_INTERCEPTOR(void, _ZNSt3__119__shared_weak_count16__release_sharedEv
,
459 fake_shared_weak_count
*o
) {
460 if (!flags()->shared_ptr_interceptor
)
461 return REAL(_ZNSt3__119__shared_weak_count16__release_sharedEv
)(o
);
463 SCOPED_TSAN_INTERCEPTOR(_ZNSt3__119__shared_weak_count16__release_sharedEv
,
465 if (__tsan_atomic64_fetch_add(&o
->shared_owners
, -1, mo_release
) == 0) {
466 Acquire(thr
, pc
, (uptr
)&o
->shared_owners
);
468 if (__tsan_atomic64_fetch_add(&o
->shared_weak_owners
, -1, mo_release
) ==
470 Acquire(thr
, pc
, (uptr
)&o
->shared_weak_owners
);
471 o
->on_zero_shared_weak();
476 STDCXX_INTERCEPTOR(bool, _ZNSt3__114__shared_count16__release_sharedEv
,
477 fake_shared_weak_count
*o
) {
478 if (!flags()->shared_ptr_interceptor
)
479 return REAL(_ZNSt3__114__shared_count16__release_sharedEv
)(o
);
481 SCOPED_TSAN_INTERCEPTOR(_ZNSt3__114__shared_count16__release_sharedEv
, o
);
482 if (__tsan_atomic64_fetch_add(&o
->shared_owners
, -1, mo_release
) == 0) {
483 Acquire(thr
, pc
, (uptr
)&o
->shared_owners
);
491 struct call_once_callback_args
{
492 void (*orig_func
)(void *arg
);
497 void call_once_callback_wrapper(void *arg
) {
498 call_once_callback_args
*new_args
= (call_once_callback_args
*)arg
;
499 new_args
->orig_func(new_args
->orig_arg
);
500 __tsan_release(new_args
->flag
);
504 // This adds a libc++ interceptor for:
505 // void __call_once(volatile unsigned long&, void*, void(*)(void*));
506 // C++11 call_once is implemented via an internal function __call_once which is
507 // inside libc++.dylib, and the atomic release store inside it is thus
508 // TSan-invisible. To avoid false positives, this interceptor wraps the callback
509 // function and performs an explicit Release after the user code has run.
510 STDCXX_INTERCEPTOR(void, _ZNSt3__111__call_onceERVmPvPFvS2_E
, void *flag
,
511 void *arg
, void (*func
)(void *arg
)) {
512 call_once_callback_args new_args
= {func
, arg
, flag
};
513 REAL(_ZNSt3__111__call_onceERVmPvPFvS2_E
)(flag
, &new_args
,
514 call_once_callback_wrapper
);
517 } // namespace __tsan
519 #endif // SANITIZER_MAC