compiler-rt/lib/tsan/rtl/tsan_libdispatch_mac.cc - nest-cam/4320010/compiler-rt - Git at Google

 //===-- tsan_libdispatch_mac.cc -------------------------------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file is a part of ThreadSanitizer (TSan), a race detector.
 //
 // Mac-specific libdispatch (GCD) support.
 //===----------------------------------------------------------------------===//

 #include "sanitizer_common/sanitizer_platform.h"
 #if SANITIZER_MAC

 #include "sanitizer_common/sanitizer_common.h"
 #include "interception/interception.h"
 #include "tsan_interceptors.h"
 #include "tsan_platform.h"
 #include "tsan_rtl.h"

 #include <Block.h>
 #include <dispatch/dispatch.h>
 #include <pthread.h>

 typedef long long_t;  // NOLINT

 namespace __tsan {

 typedef struct {
   dispatch_queue_t queue;
   void *orig_context;
   dispatch_function_t orig_work;
   uptr object_to_acquire;
   dispatch_object_t object_to_release;
 } tsan_block_context_t;

 // The offsets of different fields of the dispatch_queue_t structure, exported
 // by libdispatch.dylib.
 extern "C" struct dispatch_queue_offsets_s {
   const uint16_t dqo_version;
   const uint16_t dqo_label;
   const uint16_t dqo_label_size;
   const uint16_t dqo_flags;
   const uint16_t dqo_flags_size;
   const uint16_t dqo_serialnum;
   const uint16_t dqo_serialnum_size;
   const uint16_t dqo_width;
   const uint16_t dqo_width_size;
   const uint16_t dqo_running;
   const uint16_t dqo_running_size;
   const uint16_t dqo_suspend_cnt;
   const uint16_t dqo_suspend_cnt_size;
   const uint16_t dqo_target_queue;
   const uint16_t dqo_target_queue_size;
   const uint16_t dqo_priority;
   const uint16_t dqo_priority_size;
 } dispatch_queue_offsets;

 static bool IsQueueSerial(dispatch_queue_t q) {
   CHECK_EQ(dispatch_queue_offsets.dqo_width_size, 2);
   uptr width = *(uint16_t *)(((uptr)q) + dispatch_queue_offsets.dqo_width);
   CHECK_NE(width, 0);
   return width == 1;
 }

 static tsan_block_context_t *AllocContext(ThreadState *thr, uptr pc,
                                           dispatch_queue_t queue,
                                           void *orig_context,
                                           dispatch_function_t orig_work) {
   tsan_block_context_t *new_context =
       (tsan_block_context_t *)user_alloc(thr, pc, sizeof(tsan_block_context_t));
   new_context->queue = queue;
   new_context->orig_context = orig_context;
   new_context->orig_work = orig_work;
   new_context->object_to_acquire = (uptr)new_context;
   new_context->object_to_release = nullptr;
   return new_context;
 }

 static void dispatch_callback_wrap_acquire(void *param) {
   SCOPED_INTERCEPTOR_RAW(dispatch_async_f_callback_wrap);
   tsan_block_context_t *context = (tsan_block_context_t *)param;
   Acquire(thr, pc, context->object_to_acquire);

   // Extra retain/release is required for dispatch groups. We use the group
   // itself to synchronize, but in a notification (dispatch_group_notify
   // callback), it may be disposed already. To solve this, we retain the group
   // and release it here.
   if (context->object_to_release) dispatch_release(context->object_to_release);

   // In serial queues, work items can be executed on different threads, we need
   // to explicitly synchronize on the queue itself.
   if (IsQueueSerial(context->queue)) Acquire(thr, pc, (uptr)context->queue);
   SCOPED_TSAN_INTERCEPTOR_USER_CALLBACK_START();
   context->orig_work(context->orig_context);
   SCOPED_TSAN_INTERCEPTOR_USER_CALLBACK_END();
   if (IsQueueSerial(context->queue)) Release(thr, pc, (uptr)context->queue);
   user_free(thr, pc, context);
 }

 static void invoke_and_release_block(void *param) {
   dispatch_block_t block = (dispatch_block_t)param;
   block();
   Block_release(block);
 }

 #define DISPATCH_INTERCEPT_B(name)                                           \
   TSAN_INTERCEPTOR(void, name, dispatch_queue_t q, dispatch_block_t block) { \
     SCOPED_TSAN_INTERCEPTOR(name, q, block);                                 \
     SCOPED_TSAN_INTERCEPTOR_USER_CALLBACK_START(); \
     dispatch_block_t heap_block = Block_copy(block);                         \
     SCOPED_TSAN_INTERCEPTOR_USER_CALLBACK_END(); \
     tsan_block_context_t *new_context =                                      \
         AllocContext(thr, pc, q, heap_block, &invoke_and_release_block);     \
     Release(thr, pc, (uptr)new_context);                                     \
     SCOPED_TSAN_INTERCEPTOR_USER_CALLBACK_START(); \
     REAL(name##_f)(q, new_context, dispatch_callback_wrap_acquire);          \
     SCOPED_TSAN_INTERCEPTOR_USER_CALLBACK_END(); \
   }

 #define DISPATCH_INTERCEPT_F(name)                                \
   TSAN_INTERCEPTOR(void, name, dispatch_queue_t q, void *context, \
                    dispatch_function_t work) {                    \
     SCOPED_TSAN_INTERCEPTOR(name, q, context, work);              \
     tsan_block_context_t *new_context =                           \
         AllocContext(thr, pc, q, context, work);                  \
     Release(thr, pc, (uptr)new_context);                          \
     SCOPED_TSAN_INTERCEPTOR_USER_CALLBACK_START(); \
     REAL(name)(q, new_context, dispatch_callback_wrap_acquire);   \
     SCOPED_TSAN_INTERCEPTOR_USER_CALLBACK_END(); \
   }

 // We wrap dispatch_async, dispatch_sync and friends where we allocate a new
 // context, which is used to synchronize (we release the context before
 // submitting, and the callback acquires it before executing the original
 // callback).
 DISPATCH_INTERCEPT_B(dispatch_async)
 DISPATCH_INTERCEPT_B(dispatch_barrier_async)
 DISPATCH_INTERCEPT_F(dispatch_async_f)
 DISPATCH_INTERCEPT_F(dispatch_barrier_async_f)
 DISPATCH_INTERCEPT_B(dispatch_sync)
 DISPATCH_INTERCEPT_B(dispatch_barrier_sync)
 DISPATCH_INTERCEPT_F(dispatch_sync_f)
 DISPATCH_INTERCEPT_F(dispatch_barrier_sync_f)

 // GCD's dispatch_once implementation has a fast path that contains a racy read
 // and it's inlined into user's code. Furthermore, this fast path doesn't
 // establish a proper happens-before relations between the initialization and
 // code following the call to dispatch_once. We could deal with this in
 // instrumented code, but there's not much we can do about it in system
 // libraries. Let's disable the fast path (by never storing the value ~0 to
 // predicate), so the interceptor is always called, and let's add proper release
 // and acquire semantics. Since TSan does not see its own atomic stores, the
 // race on predicate won't be reported - the only accesses to it that TSan sees
 // are the loads on the fast path. Loads don't race. Secondly, dispatch_once is
 // both a macro and a real function, we want to intercept the function, so we
 // need to undefine the macro.
 #undef dispatch_once
 TSAN_INTERCEPTOR(void, dispatch_once, dispatch_once_t *predicate,
                  dispatch_block_t block) {
   SCOPED_TSAN_INTERCEPTOR(dispatch_once, predicate, block);
   atomic_uint32_t *a = reinterpret_cast<atomic_uint32_t *>(predicate);
   u32 v = atomic_load(a, memory_order_acquire);
   if (v == 0 &&
       atomic_compare_exchange_strong(a, &v, 1, memory_order_relaxed)) {
     SCOPED_TSAN_INTERCEPTOR_USER_CALLBACK_START();
     block();
     SCOPED_TSAN_INTERCEPTOR_USER_CALLBACK_END();
     Release(thr, pc, (uptr)a);
     atomic_store(a, 2, memory_order_release);
   } else {
     while (v != 2) {
       internal_sched_yield();
       v = atomic_load(a, memory_order_acquire);
     }
     Acquire(thr, pc, (uptr)a);
   }
 }

 #undef dispatch_once_f
 TSAN_INTERCEPTOR(void, dispatch_once_f, dispatch_once_t *predicate,
                  void *context, dispatch_function_t function) {
   SCOPED_TSAN_INTERCEPTOR(dispatch_once_f, predicate, context, function);
   SCOPED_TSAN_INTERCEPTOR_USER_CALLBACK_START();
   WRAP(dispatch_once)(predicate, ^(void) {
     function(context);
   });
   SCOPED_TSAN_INTERCEPTOR_USER_CALLBACK_END();
 }

 TSAN_INTERCEPTOR(long_t, dispatch_semaphore_signal,
                  dispatch_semaphore_t dsema) {
   SCOPED_TSAN_INTERCEPTOR(dispatch_semaphore_signal, dsema);
   Release(thr, pc, (uptr)dsema);
   return REAL(dispatch_semaphore_signal)(dsema);
 }

 TSAN_INTERCEPTOR(long_t, dispatch_semaphore_wait, dispatch_semaphore_t dsema,
                  dispatch_time_t timeout) {
   SCOPED_TSAN_INTERCEPTOR(dispatch_semaphore_wait, dsema, timeout);
   long_t result = REAL(dispatch_semaphore_wait)(dsema, timeout);
   if (result == 0) Acquire(thr, pc, (uptr)dsema);
   return result;
 }

 TSAN_INTERCEPTOR(long_t, dispatch_group_wait, dispatch_group_t group,
                  dispatch_time_t timeout) {
   SCOPED_TSAN_INTERCEPTOR(dispatch_group_wait, group, timeout);
   long_t result = REAL(dispatch_group_wait)(group, timeout);
   if (result == 0) Acquire(thr, pc, (uptr)group);
   return result;
 }

 TSAN_INTERCEPTOR(void, dispatch_group_leave, dispatch_group_t group) {
   SCOPED_TSAN_INTERCEPTOR(dispatch_group_leave, group);
   Release(thr, pc, (uptr)group);
   REAL(dispatch_group_leave)(group);
 }

 TSAN_INTERCEPTOR(void, dispatch_group_async, dispatch_group_t group,
                  dispatch_queue_t queue, dispatch_block_t block) {
   SCOPED_TSAN_INTERCEPTOR(dispatch_group_async, group, queue, block);
   dispatch_retain(group);
   dispatch_group_enter(group);
   WRAP(dispatch_async)(queue, ^(void) {
     block();
     WRAP(dispatch_group_leave)(group);
     dispatch_release(group);
   });
 }

 TSAN_INTERCEPTOR(void, dispatch_group_async_f, dispatch_group_t group,
                  dispatch_queue_t queue, void *context,
                  dispatch_function_t work) {
   SCOPED_TSAN_INTERCEPTOR(dispatch_group_async_f, group, queue, context, work);
   dispatch_retain(group);
   dispatch_group_enter(group);
   WRAP(dispatch_async)(queue, ^(void) {
     work(context);
     WRAP(dispatch_group_leave)(group);
     dispatch_release(group);
   });
 }

 TSAN_INTERCEPTOR(void, dispatch_group_notify, dispatch_group_t group,
                  dispatch_queue_t q, dispatch_block_t block) {
   SCOPED_TSAN_INTERCEPTOR(dispatch_group_notify, group, q, block);
   SCOPED_TSAN_INTERCEPTOR_USER_CALLBACK_START();
   dispatch_block_t heap_block = Block_copy(block);
   SCOPED_TSAN_INTERCEPTOR_USER_CALLBACK_END();
   tsan_block_context_t *new_context =
       AllocContext(thr, pc, q, heap_block, &invoke_and_release_block);
   new_context->object_to_acquire = (uptr)group;

   // Will be released in dispatch_callback_wrap_acquire.
   new_context->object_to_release = group;
   dispatch_retain(group);

   Release(thr, pc, (uptr)group);
   REAL(dispatch_group_notify_f)(group, q, new_context,
                                 dispatch_callback_wrap_acquire);
 }

 TSAN_INTERCEPTOR(void, dispatch_group_notify_f, dispatch_group_t group,
                  dispatch_queue_t q, void *context, dispatch_function_t work) {
   SCOPED_TSAN_INTERCEPTOR(dispatch_group_notify_f, group, q, context, work);
   tsan_block_context_t *new_context = AllocContext(thr, pc, q, context, work);
   new_context->object_to_acquire = (uptr)group;

   // Will be released in dispatch_callback_wrap_acquire.
   new_context->object_to_release = group;
   dispatch_retain(group);

   Release(thr, pc, (uptr)group);
   REAL(dispatch_group_notify_f)(group, q, new_context,
                                 dispatch_callback_wrap_acquire);
 }

 }  // namespace __tsan

 #endif  // SANITIZER_MAC
	//===-- tsan_libdispatch_mac.cc -------------------------------------------===//
	//
	// The LLVM Compiler Infrastructure
	//
	// This file is distributed under the University of Illinois Open Source
	// License. See LICENSE.TXT for details.
	//
	//===----------------------------------------------------------------------===//
	//
	// This file is a part of ThreadSanitizer (TSan), a race detector.
	//
	// Mac-specific libdispatch (GCD) support.
	//===----------------------------------------------------------------------===//

	#include "sanitizer_common/sanitizer_platform.h"
	#if SANITIZER_MAC

	#include "sanitizer_common/sanitizer_common.h"
	#include "interception/interception.h"
	#include "tsan_interceptors.h"
	#include "tsan_platform.h"
	#include "tsan_rtl.h"

	#include <Block.h>
	#include <dispatch/dispatch.h>
	#include <pthread.h>

	typedef long long_t; // NOLINT

	namespace __tsan {

	typedef struct {
	dispatch_queue_t queue;
	void *orig_context;
	dispatch_function_t orig_work;
	uptr object_to_acquire;
	dispatch_object_t object_to_release;
	} tsan_block_context_t;

	// The offsets of different fields of the dispatch_queue_t structure, exported
	// by libdispatch.dylib.
	extern "C" struct dispatch_queue_offsets_s {
	const uint16_t dqo_version;
	const uint16_t dqo_label;
	const uint16_t dqo_label_size;
	const uint16_t dqo_flags;
	const uint16_t dqo_flags_size;
	const uint16_t dqo_serialnum;
	const uint16_t dqo_serialnum_size;
	const uint16_t dqo_width;
	const uint16_t dqo_width_size;
	const uint16_t dqo_running;
	const uint16_t dqo_running_size;
	const uint16_t dqo_suspend_cnt;
	const uint16_t dqo_suspend_cnt_size;
	const uint16_t dqo_target_queue;
	const uint16_t dqo_target_queue_size;
	const uint16_t dqo_priority;
	const uint16_t dqo_priority_size;
	} dispatch_queue_offsets;

	static bool IsQueueSerial(dispatch_queue_t q) {
	CHECK_EQ(dispatch_queue_offsets.dqo_width_size, 2);
	uptr width = (uint16_t )(((uptr)q) + dispatch_queue_offsets.dqo_width);
	CHECK_NE(width, 0);
	return width == 1;
	}

	static tsan_block_context_t AllocContext(ThreadState thr, uptr pc,
	dispatch_queue_t queue,
	void *orig_context,
	dispatch_function_t orig_work) {
	tsan_block_context_t *new_context =
	(tsan_block_context_t *)user_alloc(thr, pc, sizeof(tsan_block_context_t));
	new_context->queue = queue;
	new_context->orig_context = orig_context;
	new_context->orig_work = orig_work;
	new_context->object_to_acquire = (uptr)new_context;
	new_context->object_to_release = nullptr;
	return new_context;
	}

	static void dispatch_callback_wrap_acquire(void *param) {
	SCOPED_INTERCEPTOR_RAW(dispatch_async_f_callback_wrap);
	tsan_block_context_t context = (tsan_block_context_t )param;
	Acquire(thr, pc, context->object_to_acquire);

	// Extra retain/release is required for dispatch groups. We use the group
	// itself to synchronize, but in a notification (dispatch_group_notify
	// callback), it may be disposed already. To solve this, we retain the group
	// and release it here.
	if (context->object_to_release) dispatch_release(context->object_to_release);

	// In serial queues, work items can be executed on different threads, we need
	// to explicitly synchronize on the queue itself.
	if (IsQueueSerial(context->queue)) Acquire(thr, pc, (uptr)context->queue);
	SCOPED_TSAN_INTERCEPTOR_USER_CALLBACK_START();
	context->orig_work(context->orig_context);
	SCOPED_TSAN_INTERCEPTOR_USER_CALLBACK_END();
	if (IsQueueSerial(context->queue)) Release(thr, pc, (uptr)context->queue);
	user_free(thr, pc, context);
	}

	static void invoke_and_release_block(void *param) {
	dispatch_block_t block = (dispatch_block_t)param;
	block();
	Block_release(block);
	}

	#define DISPATCH_INTERCEPT_B(name) \
	TSAN_INTERCEPTOR(void, name, dispatch_queue_t q, dispatch_block_t block) { \
	SCOPED_TSAN_INTERCEPTOR(name, q, block); \
	SCOPED_TSAN_INTERCEPTOR_USER_CALLBACK_START(); \
	dispatch_block_t heap_block = Block_copy(block); \
	SCOPED_TSAN_INTERCEPTOR_USER_CALLBACK_END(); \
	tsan_block_context_t *new_context = \
	AllocContext(thr, pc, q, heap_block, &invoke_and_release_block); \
	Release(thr, pc, (uptr)new_context); \
	SCOPED_TSAN_INTERCEPTOR_USER_CALLBACK_START(); \
	REAL(name##_f)(q, new_context, dispatch_callback_wrap_acquire); \
	SCOPED_TSAN_INTERCEPTOR_USER_CALLBACK_END(); \
	}

	#define DISPATCH_INTERCEPT_F(name) \
	TSAN_INTERCEPTOR(void, name, dispatch_queue_t q, void *context, \
	dispatch_function_t work) { \
	SCOPED_TSAN_INTERCEPTOR(name, q, context, work); \
	tsan_block_context_t *new_context = \
	AllocContext(thr, pc, q, context, work); \
	Release(thr, pc, (uptr)new_context); \
	SCOPED_TSAN_INTERCEPTOR_USER_CALLBACK_START(); \
	REAL(name)(q, new_context, dispatch_callback_wrap_acquire); \
	SCOPED_TSAN_INTERCEPTOR_USER_CALLBACK_END(); \
	}

	// We wrap dispatch_async, dispatch_sync and friends where we allocate a new
	// context, which is used to synchronize (we release the context before
	// submitting, and the callback acquires it before executing the original
	// callback).
	DISPATCH_INTERCEPT_B(dispatch_async)
	DISPATCH_INTERCEPT_B(dispatch_barrier_async)
	DISPATCH_INTERCEPT_F(dispatch_async_f)
	DISPATCH_INTERCEPT_F(dispatch_barrier_async_f)
	DISPATCH_INTERCEPT_B(dispatch_sync)
	DISPATCH_INTERCEPT_B(dispatch_barrier_sync)
	DISPATCH_INTERCEPT_F(dispatch_sync_f)
	DISPATCH_INTERCEPT_F(dispatch_barrier_sync_f)

	// GCD's dispatch_once implementation has a fast path that contains a racy read
	// and it's inlined into user's code. Furthermore, this fast path doesn't
	// establish a proper happens-before relations between the initialization and
	// code following the call to dispatch_once. We could deal with this in
	// instrumented code, but there's not much we can do about it in system
	// libraries. Let's disable the fast path (by never storing the value ~0 to
	// predicate), so the interceptor is always called, and let's add proper release
	// and acquire semantics. Since TSan does not see its own atomic stores, the
	// race on predicate won't be reported - the only accesses to it that TSan sees
	// are the loads on the fast path. Loads don't race. Secondly, dispatch_once is
	// both a macro and a real function, we want to intercept the function, so we
	// need to undefine the macro.
	#undef dispatch_once
	TSAN_INTERCEPTOR(void, dispatch_once, dispatch_once_t *predicate,
	dispatch_block_t block) {
	SCOPED_TSAN_INTERCEPTOR(dispatch_once, predicate, block);
	atomic_uint32_t a = reinterpret_cast<atomic_uint32_t >(predicate);
	u32 v = atomic_load(a, memory_order_acquire);
	if (v == 0 &&
	atomic_compare_exchange_strong(a, &v, 1, memory_order_relaxed)) {
	SCOPED_TSAN_INTERCEPTOR_USER_CALLBACK_START();
	block();
	SCOPED_TSAN_INTERCEPTOR_USER_CALLBACK_END();
	Release(thr, pc, (uptr)a);
	atomic_store(a, 2, memory_order_release);
	} else {
	while (v != 2) {
	internal_sched_yield();
	v = atomic_load(a, memory_order_acquire);
	}
	Acquire(thr, pc, (uptr)a);
	}
	}

	#undef dispatch_once_f
	TSAN_INTERCEPTOR(void, dispatch_once_f, dispatch_once_t *predicate,
	void *context, dispatch_function_t function) {
	SCOPED_TSAN_INTERCEPTOR(dispatch_once_f, predicate, context, function);
	SCOPED_TSAN_INTERCEPTOR_USER_CALLBACK_START();
	WRAP(dispatch_once)(predicate, ^(void) {
	function(context);
	});
	SCOPED_TSAN_INTERCEPTOR_USER_CALLBACK_END();
	}

	TSAN_INTERCEPTOR(long_t, dispatch_semaphore_signal,
	dispatch_semaphore_t dsema) {
	SCOPED_TSAN_INTERCEPTOR(dispatch_semaphore_signal, dsema);
	Release(thr, pc, (uptr)dsema);
	return REAL(dispatch_semaphore_signal)(dsema);
	}

	TSAN_INTERCEPTOR(long_t, dispatch_semaphore_wait, dispatch_semaphore_t dsema,
	dispatch_time_t timeout) {
	SCOPED_TSAN_INTERCEPTOR(dispatch_semaphore_wait, dsema, timeout);
	long_t result = REAL(dispatch_semaphore_wait)(dsema, timeout);
	if (result == 0) Acquire(thr, pc, (uptr)dsema);
	return result;
	}

	TSAN_INTERCEPTOR(long_t, dispatch_group_wait, dispatch_group_t group,
	dispatch_time_t timeout) {
	SCOPED_TSAN_INTERCEPTOR(dispatch_group_wait, group, timeout);
	long_t result = REAL(dispatch_group_wait)(group, timeout);
	if (result == 0) Acquire(thr, pc, (uptr)group);
	return result;
	}

	TSAN_INTERCEPTOR(void, dispatch_group_leave, dispatch_group_t group) {
	SCOPED_TSAN_INTERCEPTOR(dispatch_group_leave, group);
	Release(thr, pc, (uptr)group);
	REAL(dispatch_group_leave)(group);
	}

	TSAN_INTERCEPTOR(void, dispatch_group_async, dispatch_group_t group,
	dispatch_queue_t queue, dispatch_block_t block) {
	SCOPED_TSAN_INTERCEPTOR(dispatch_group_async, group, queue, block);
	dispatch_retain(group);
	dispatch_group_enter(group);
	WRAP(dispatch_async)(queue, ^(void) {
	block();
	WRAP(dispatch_group_leave)(group);
	dispatch_release(group);
	});
	}

	TSAN_INTERCEPTOR(void, dispatch_group_async_f, dispatch_group_t group,
	dispatch_queue_t queue, void *context,
	dispatch_function_t work) {
	SCOPED_TSAN_INTERCEPTOR(dispatch_group_async_f, group, queue, context, work);
	dispatch_retain(group);
	dispatch_group_enter(group);
	WRAP(dispatch_async)(queue, ^(void) {
	work(context);
	WRAP(dispatch_group_leave)(group);
	dispatch_release(group);
	});
	}

	TSAN_INTERCEPTOR(void, dispatch_group_notify, dispatch_group_t group,
	dispatch_queue_t q, dispatch_block_t block) {
	SCOPED_TSAN_INTERCEPTOR(dispatch_group_notify, group, q, block);
	SCOPED_TSAN_INTERCEPTOR_USER_CALLBACK_START();
	dispatch_block_t heap_block = Block_copy(block);
	SCOPED_TSAN_INTERCEPTOR_USER_CALLBACK_END();
	tsan_block_context_t *new_context =
	AllocContext(thr, pc, q, heap_block, &invoke_and_release_block);
	new_context->object_to_acquire = (uptr)group;

	// Will be released in dispatch_callback_wrap_acquire.
	new_context->object_to_release = group;
	dispatch_retain(group);

	Release(thr, pc, (uptr)group);
	REAL(dispatch_group_notify_f)(group, q, new_context,
	dispatch_callback_wrap_acquire);
	}

	TSAN_INTERCEPTOR(void, dispatch_group_notify_f, dispatch_group_t group,
	dispatch_queue_t q, void *context, dispatch_function_t work) {
	SCOPED_TSAN_INTERCEPTOR(dispatch_group_notify_f, group, q, context, work);
	tsan_block_context_t *new_context = AllocContext(thr, pc, q, context, work);
	new_context->object_to_acquire = (uptr)group;

	// Will be released in dispatch_callback_wrap_acquire.
	new_context->object_to_release = group;
	dispatch_retain(group);

	Release(thr, pc, (uptr)group);
	REAL(dispatch_group_notify_f)(group, q, new_context,
	dispatch_callback_wrap_acquire);
	}

	} // namespace __tsan

	#endif // SANITIZER_MAC