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diff --git a/lib/tsan/rtl/tsan_interceptors_mac.cpp b/lib/tsan/rtl/tsan_interceptors_mac.cpp
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+//===-- tsan_interceptors_mac.cpp -----------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is a part of ThreadSanitizer (TSan), a race detector.
+//
+// Mac-specific interceptors.
+//===----------------------------------------------------------------------===//
+
+#include "sanitizer_common/sanitizer_platform.h"
+#if SANITIZER_MAC
+
+#include "interception/interception.h"
+#include "tsan_interceptors.h"
+#include "tsan_interface.h"
+#include "tsan_interface_ann.h"
+#include "sanitizer_common/sanitizer_addrhashmap.h"
+
+#include <errno.h>
+#include <libkern/OSAtomic.h>
+#include <objc/objc-sync.h>
+#include <os/lock.h>
+#include <sys/ucontext.h>
+
+#if defined(__has_include) && __has_include(<xpc/xpc.h>)
+#include <xpc/xpc.h>
+#endif // #if defined(__has_include) && __has_include(<xpc/xpc.h>)
+
+typedef long long_t;
+
+extern "C" {
+int getcontext(ucontext_t *ucp) __attribute__((returns_twice));
+int setcontext(const ucontext_t *ucp);
+}
+
+namespace __tsan {
+
+// The non-barrier versions of OSAtomic* functions are semantically mo_relaxed,
+// but the two variants (e.g. OSAtomicAdd32 and OSAtomicAdd32Barrier) are
+// actually aliases of each other, and we cannot have different interceptors for
+// them, because they're actually the same function. Thus, we have to stay
+// conservative and treat the non-barrier versions as mo_acq_rel.
+static const morder kMacOrderBarrier = mo_acq_rel;
+static const morder kMacOrderNonBarrier = mo_acq_rel;
+
+#define OSATOMIC_INTERCEPTOR(return_t, t, tsan_t, f, tsan_atomic_f, mo) \
+ TSAN_INTERCEPTOR(return_t, f, t x, volatile t *ptr) { \
+ SCOPED_TSAN_INTERCEPTOR(f, x, ptr); \
+ return tsan_atomic_f((volatile tsan_t *)ptr, x, mo); \
+ }
+
+#define OSATOMIC_INTERCEPTOR_PLUS_X(return_t, t, tsan_t, f, tsan_atomic_f, mo) \
+ TSAN_INTERCEPTOR(return_t, f, t x, volatile t *ptr) { \
+ SCOPED_TSAN_INTERCEPTOR(f, x, ptr); \
+ return tsan_atomic_f((volatile tsan_t *)ptr, x, mo) + x; \
+ }
+
+#define OSATOMIC_INTERCEPTOR_PLUS_1(return_t, t, tsan_t, f, tsan_atomic_f, mo) \
+ TSAN_INTERCEPTOR(return_t, f, volatile t *ptr) { \
+ SCOPED_TSAN_INTERCEPTOR(f, ptr); \
+ return tsan_atomic_f((volatile tsan_t *)ptr, 1, mo) + 1; \
+ }
+
+#define OSATOMIC_INTERCEPTOR_MINUS_1(return_t, t, tsan_t, f, tsan_atomic_f, \
+ mo) \
+ TSAN_INTERCEPTOR(return_t, f, volatile t *ptr) { \
+ SCOPED_TSAN_INTERCEPTOR(f, ptr); \
+ return tsan_atomic_f((volatile tsan_t *)ptr, 1, mo) - 1; \
+ }
+
+#define OSATOMIC_INTERCEPTORS_ARITHMETIC(f, tsan_atomic_f, m) \
+ m(int32_t, int32_t, a32, f##32, __tsan_atomic32_##tsan_atomic_f, \
+ kMacOrderNonBarrier) \
+ m(int32_t, int32_t, a32, f##32##Barrier, __tsan_atomic32_##tsan_atomic_f, \
+ kMacOrderBarrier) \
+ m(int64_t, int64_t, a64, f##64, __tsan_atomic64_##tsan_atomic_f, \
+ kMacOrderNonBarrier) \
+ m(int64_t, int64_t, a64, f##64##Barrier, __tsan_atomic64_##tsan_atomic_f, \
+ kMacOrderBarrier)
+
+#define OSATOMIC_INTERCEPTORS_BITWISE(f, tsan_atomic_f, m, m_orig) \
+ m(int32_t, uint32_t, a32, f##32, __tsan_atomic32_##tsan_atomic_f, \
+ kMacOrderNonBarrier) \
+ m(int32_t, uint32_t, a32, f##32##Barrier, __tsan_atomic32_##tsan_atomic_f, \
+ kMacOrderBarrier) \
+ m_orig(int32_t, uint32_t, a32, f##32##Orig, __tsan_atomic32_##tsan_atomic_f, \
+ kMacOrderNonBarrier) \
+ m_orig(int32_t, uint32_t, a32, f##32##OrigBarrier, \
+ __tsan_atomic32_##tsan_atomic_f, kMacOrderBarrier)
+
+OSATOMIC_INTERCEPTORS_ARITHMETIC(OSAtomicAdd, fetch_add,
+ OSATOMIC_INTERCEPTOR_PLUS_X)
+OSATOMIC_INTERCEPTORS_ARITHMETIC(OSAtomicIncrement, fetch_add,
+ OSATOMIC_INTERCEPTOR_PLUS_1)
+OSATOMIC_INTERCEPTORS_ARITHMETIC(OSAtomicDecrement, fetch_sub,
+ OSATOMIC_INTERCEPTOR_MINUS_1)
+OSATOMIC_INTERCEPTORS_BITWISE(OSAtomicOr, fetch_or, OSATOMIC_INTERCEPTOR_PLUS_X,
+ OSATOMIC_INTERCEPTOR)
+OSATOMIC_INTERCEPTORS_BITWISE(OSAtomicAnd, fetch_and,
+ OSATOMIC_INTERCEPTOR_PLUS_X, OSATOMIC_INTERCEPTOR)
+OSATOMIC_INTERCEPTORS_BITWISE(OSAtomicXor, fetch_xor,
+ OSATOMIC_INTERCEPTOR_PLUS_X, OSATOMIC_INTERCEPTOR)
+
+#define OSATOMIC_INTERCEPTORS_CAS(f, tsan_atomic_f, tsan_t, t) \
+ TSAN_INTERCEPTOR(bool, f, t old_value, t new_value, t volatile *ptr) { \
+ SCOPED_TSAN_INTERCEPTOR(f, old_value, new_value, ptr); \
+ return tsan_atomic_f##_compare_exchange_strong( \
+ (volatile tsan_t *)ptr, (tsan_t *)&old_value, (tsan_t)new_value, \
+ kMacOrderNonBarrier, kMacOrderNonBarrier); \
+ } \
+ \
+ TSAN_INTERCEPTOR(bool, f##Barrier, t old_value, t new_value, \
+ t volatile *ptr) { \
+ SCOPED_TSAN_INTERCEPTOR(f##Barrier, old_value, new_value, ptr); \
+ return tsan_atomic_f##_compare_exchange_strong( \
+ (volatile tsan_t *)ptr, (tsan_t *)&old_value, (tsan_t)new_value, \
+ kMacOrderBarrier, kMacOrderNonBarrier); \
+ }
+
+OSATOMIC_INTERCEPTORS_CAS(OSAtomicCompareAndSwapInt, __tsan_atomic32, a32, int)
+OSATOMIC_INTERCEPTORS_CAS(OSAtomicCompareAndSwapLong, __tsan_atomic64, a64,
+ long_t)
+OSATOMIC_INTERCEPTORS_CAS(OSAtomicCompareAndSwapPtr, __tsan_atomic64, a64,
+ void *)
+OSATOMIC_INTERCEPTORS_CAS(OSAtomicCompareAndSwap32, __tsan_atomic32, a32,
+ int32_t)
+OSATOMIC_INTERCEPTORS_CAS(OSAtomicCompareAndSwap64, __tsan_atomic64, a64,
+ int64_t)
+
+#define OSATOMIC_INTERCEPTOR_BITOP(f, op, clear, mo) \
+ TSAN_INTERCEPTOR(bool, f, uint32_t n, volatile void *ptr) { \
+ SCOPED_TSAN_INTERCEPTOR(f, n, ptr); \
+ volatile char *byte_ptr = ((volatile char *)ptr) + (n >> 3); \
+ char bit = 0x80u >> (n & 7); \
+ char mask = clear ? ~bit : bit; \
+ char orig_byte = op((volatile a8 *)byte_ptr, mask, mo); \
+ return orig_byte & bit; \
+ }
+
+#define OSATOMIC_INTERCEPTORS_BITOP(f, op, clear) \
+ OSATOMIC_INTERCEPTOR_BITOP(f, op, clear, kMacOrderNonBarrier) \
+ OSATOMIC_INTERCEPTOR_BITOP(f##Barrier, op, clear, kMacOrderBarrier)
+
+OSATOMIC_INTERCEPTORS_BITOP(OSAtomicTestAndSet, __tsan_atomic8_fetch_or, false)
+OSATOMIC_INTERCEPTORS_BITOP(OSAtomicTestAndClear, __tsan_atomic8_fetch_and,
+ true)
+
+TSAN_INTERCEPTOR(void, OSAtomicEnqueue, OSQueueHead *list, void *item,
+ size_t offset) {
+ SCOPED_TSAN_INTERCEPTOR(OSAtomicEnqueue, list, item, offset);
+ __tsan_release(item);
+ REAL(OSAtomicEnqueue)(list, item, offset);
+}
+
+TSAN_INTERCEPTOR(void *, OSAtomicDequeue, OSQueueHead *list, size_t offset) {
+ SCOPED_TSAN_INTERCEPTOR(OSAtomicDequeue, list, offset);
+ void *item = REAL(OSAtomicDequeue)(list, offset);
+ if (item) __tsan_acquire(item);
+ return item;
+}
+
+// OSAtomicFifoEnqueue and OSAtomicFifoDequeue are only on OS X.
+#if !SANITIZER_IOS
+
+TSAN_INTERCEPTOR(void, OSAtomicFifoEnqueue, OSFifoQueueHead *list, void *item,
+ size_t offset) {
+ SCOPED_TSAN_INTERCEPTOR(OSAtomicFifoEnqueue, list, item, offset);
+ __tsan_release(item);
+ REAL(OSAtomicFifoEnqueue)(list, item, offset);
+}
+
+TSAN_INTERCEPTOR(void *, OSAtomicFifoDequeue, OSFifoQueueHead *list,
+ size_t offset) {
+ SCOPED_TSAN_INTERCEPTOR(OSAtomicFifoDequeue, list, offset);
+ void *item = REAL(OSAtomicFifoDequeue)(list, offset);
+ if (item) __tsan_acquire(item);
+ return item;
+}
+
+#endif
+
+TSAN_INTERCEPTOR(void, OSSpinLockLock, volatile OSSpinLock *lock) {
+ CHECK(!cur_thread()->is_dead);
+ if (!cur_thread()->is_inited) {
+ return REAL(OSSpinLockLock)(lock);
+ }
+ SCOPED_TSAN_INTERCEPTOR(OSSpinLockLock, lock);
+ REAL(OSSpinLockLock)(lock);
+ Acquire(thr, pc, (uptr)lock);
+}
+
+TSAN_INTERCEPTOR(bool, OSSpinLockTry, volatile OSSpinLock *lock) {
+ CHECK(!cur_thread()->is_dead);
+ if (!cur_thread()->is_inited) {
+ return REAL(OSSpinLockTry)(lock);
+ }
+ SCOPED_TSAN_INTERCEPTOR(OSSpinLockTry, lock);
+ bool result = REAL(OSSpinLockTry)(lock);
+ if (result)
+ Acquire(thr, pc, (uptr)lock);
+ return result;
+}
+
+TSAN_INTERCEPTOR(void, OSSpinLockUnlock, volatile OSSpinLock *lock) {
+ CHECK(!cur_thread()->is_dead);
+ if (!cur_thread()->is_inited) {
+ return REAL(OSSpinLockUnlock)(lock);
+ }
+ SCOPED_TSAN_INTERCEPTOR(OSSpinLockUnlock, lock);
+ Release(thr, pc, (uptr)lock);
+ REAL(OSSpinLockUnlock)(lock);
+}
+
+TSAN_INTERCEPTOR(void, os_lock_lock, void *lock) {
+ CHECK(!cur_thread()->is_dead);
+ if (!cur_thread()->is_inited) {
+ return REAL(os_lock_lock)(lock);
+ }
+ SCOPED_TSAN_INTERCEPTOR(os_lock_lock, lock);
+ REAL(os_lock_lock)(lock);
+ Acquire(thr, pc, (uptr)lock);
+}
+
+TSAN_INTERCEPTOR(bool, os_lock_trylock, void *lock) {
+ CHECK(!cur_thread()->is_dead);
+ if (!cur_thread()->is_inited) {
+ return REAL(os_lock_trylock)(lock);
+ }
+ SCOPED_TSAN_INTERCEPTOR(os_lock_trylock, lock);
+ bool result = REAL(os_lock_trylock)(lock);
+ if (result)
+ Acquire(thr, pc, (uptr)lock);
+ return result;
+}
+
+TSAN_INTERCEPTOR(void, os_lock_unlock, void *lock) {
+ CHECK(!cur_thread()->is_dead);
+ if (!cur_thread()->is_inited) {
+ return REAL(os_lock_unlock)(lock);
+ }
+ SCOPED_TSAN_INTERCEPTOR(os_lock_unlock, lock);
+ Release(thr, pc, (uptr)lock);
+ REAL(os_lock_unlock)(lock);
+}
+
+TSAN_INTERCEPTOR(void, os_unfair_lock_lock, os_unfair_lock_t lock) {
+ if (!cur_thread()->is_inited || cur_thread()->is_dead) {
+ return REAL(os_unfair_lock_lock)(lock);
+ }
+ SCOPED_TSAN_INTERCEPTOR(os_unfair_lock_lock, lock);
+ REAL(os_unfair_lock_lock)(lock);
+ Acquire(thr, pc, (uptr)lock);
+}
+
+TSAN_INTERCEPTOR(void, os_unfair_lock_lock_with_options, os_unfair_lock_t lock,
+ u32 options) {
+ if (!cur_thread()->is_inited || cur_thread()->is_dead) {
+ return REAL(os_unfair_lock_lock_with_options)(lock, options);
+ }
+ SCOPED_TSAN_INTERCEPTOR(os_unfair_lock_lock_with_options, lock, options);
+ REAL(os_unfair_lock_lock_with_options)(lock, options);
+ Acquire(thr, pc, (uptr)lock);
+}
+
+TSAN_INTERCEPTOR(bool, os_unfair_lock_trylock, os_unfair_lock_t lock) {
+ if (!cur_thread()->is_inited || cur_thread()->is_dead) {
+ return REAL(os_unfair_lock_trylock)(lock);
+ }
+ SCOPED_TSAN_INTERCEPTOR(os_unfair_lock_trylock, lock);
+ bool result = REAL(os_unfair_lock_trylock)(lock);
+ if (result)
+ Acquire(thr, pc, (uptr)lock);
+ return result;
+}
+
+TSAN_INTERCEPTOR(void, os_unfair_lock_unlock, os_unfair_lock_t lock) {
+ if (!cur_thread()->is_inited || cur_thread()->is_dead) {
+ return REAL(os_unfair_lock_unlock)(lock);
+ }
+ SCOPED_TSAN_INTERCEPTOR(os_unfair_lock_unlock, lock);
+ Release(thr, pc, (uptr)lock);
+ REAL(os_unfair_lock_unlock)(lock);
+}
+
+#if defined(__has_include) && __has_include(<xpc/xpc.h>)
+
+TSAN_INTERCEPTOR(void, xpc_connection_set_event_handler,
+ xpc_connection_t connection, xpc_handler_t handler) {
+ SCOPED_TSAN_INTERCEPTOR(xpc_connection_set_event_handler, connection,
+ handler);
+ Release(thr, pc, (uptr)connection);
+ xpc_handler_t new_handler = ^(xpc_object_t object) {
+ {
+ SCOPED_INTERCEPTOR_RAW(xpc_connection_set_event_handler);
+ Acquire(thr, pc, (uptr)connection);
+ }
+ handler(object);
+ };
+ REAL(xpc_connection_set_event_handler)(connection, new_handler);
+}
+
+TSAN_INTERCEPTOR(void, xpc_connection_send_barrier, xpc_connection_t connection,
+ dispatch_block_t barrier) {
+ SCOPED_TSAN_INTERCEPTOR(xpc_connection_send_barrier, connection, barrier);
+ Release(thr, pc, (uptr)connection);
+ dispatch_block_t new_barrier = ^() {
+ {
+ SCOPED_INTERCEPTOR_RAW(xpc_connection_send_barrier);
+ Acquire(thr, pc, (uptr)connection);
+ }
+ barrier();
+ };
+ REAL(xpc_connection_send_barrier)(connection, new_barrier);
+}
+
+TSAN_INTERCEPTOR(void, xpc_connection_send_message_with_reply,
+ xpc_connection_t connection, xpc_object_t message,
+ dispatch_queue_t replyq, xpc_handler_t handler) {
+ SCOPED_TSAN_INTERCEPTOR(xpc_connection_send_message_with_reply, connection,
+ message, replyq, handler);
+ Release(thr, pc, (uptr)connection);
+ xpc_handler_t new_handler = ^(xpc_object_t object) {
+ {
+ SCOPED_INTERCEPTOR_RAW(xpc_connection_send_message_with_reply);
+ Acquire(thr, pc, (uptr)connection);
+ }
+ handler(object);
+ };
+ REAL(xpc_connection_send_message_with_reply)
+ (connection, message, replyq, new_handler);
+}
+
+TSAN_INTERCEPTOR(void, xpc_connection_cancel, xpc_connection_t connection) {
+ SCOPED_TSAN_INTERCEPTOR(xpc_connection_cancel, connection);
+ Release(thr, pc, (uptr)connection);
+ REAL(xpc_connection_cancel)(connection);
+}
+
+#endif // #if defined(__has_include) && __has_include(<xpc/xpc.h>)
+
+// Determines whether the Obj-C object pointer is a tagged pointer. Tagged
+// pointers encode the object data directly in their pointer bits and do not
+// have an associated memory allocation. The Obj-C runtime uses tagged pointers
+// to transparently optimize small objects.
+static bool IsTaggedObjCPointer(id obj) {
+ const uptr kPossibleTaggedBits = 0x8000000000000001ull;
+ return ((uptr)obj & kPossibleTaggedBits) != 0;
+}
+
+// Returns an address which can be used to inform TSan about synchronization
+// points (MutexLock/Unlock). The TSan infrastructure expects this to be a valid
+// address in the process space. We do a small allocation here to obtain a
+// stable address (the array backing the hash map can change). The memory is
+// never free'd (leaked) and allocation and locking are slow, but this code only
+// runs for @synchronized with tagged pointers, which is very rare.
+static uptr GetOrCreateSyncAddress(uptr addr, ThreadState *thr, uptr pc) {
+ typedef AddrHashMap<uptr, 5> Map;
+ static Map Addresses;
+ Map::Handle h(&Addresses, addr);
+ if (h.created()) {
+ ThreadIgnoreBegin(thr, pc);
+ *h = (uptr) user_alloc(thr, pc, /*size=*/1);
+ ThreadIgnoreEnd(thr, pc);
+ }
+ return *h;
+}
+
+// Returns an address on which we can synchronize given an Obj-C object pointer.
+// For normal object pointers, this is just the address of the object in memory.
+// Tagged pointers are not backed by an actual memory allocation, so we need to
+// synthesize a valid address.
+static uptr SyncAddressForObjCObject(id obj, ThreadState *thr, uptr pc) {
+ if (IsTaggedObjCPointer(obj))
+ return GetOrCreateSyncAddress((uptr)obj, thr, pc);
+ return (uptr)obj;
+}
+
+TSAN_INTERCEPTOR(int, objc_sync_enter, id obj) {
+ SCOPED_TSAN_INTERCEPTOR(objc_sync_enter, obj);
+ if (!obj) return REAL(objc_sync_enter)(obj);
+ uptr addr = SyncAddressForObjCObject(obj, thr, pc);
+ MutexPreLock(thr, pc, addr, MutexFlagWriteReentrant);
+ int result = REAL(objc_sync_enter)(obj);
+ CHECK_EQ(result, OBJC_SYNC_SUCCESS);
+ MutexPostLock(thr, pc, addr, MutexFlagWriteReentrant);
+ return result;
+}
+
+TSAN_INTERCEPTOR(int, objc_sync_exit, id obj) {
+ SCOPED_TSAN_INTERCEPTOR(objc_sync_exit, obj);
+ if (!obj) return REAL(objc_sync_exit)(obj);
+ uptr addr = SyncAddressForObjCObject(obj, thr, pc);
+ MutexUnlock(thr, pc, addr);
+ int result = REAL(objc_sync_exit)(obj);
+ if (result != OBJC_SYNC_SUCCESS) MutexInvalidAccess(thr, pc, addr);
+ return result;
+}
+
+TSAN_INTERCEPTOR(int, swapcontext, ucontext_t *oucp, const ucontext_t *ucp) {
+ {
+ SCOPED_INTERCEPTOR_RAW(swapcontext, oucp, ucp);
+ }
+ // Bacause of swapcontext() semantics we have no option but to copy its
+ // impementation here
+ if (!oucp || !ucp) {
+ errno = EINVAL;
+ return -1;
+ }
+ ThreadState *thr = cur_thread();
+ const int UCF_SWAPPED = 0x80000000;
+ oucp->uc_onstack &= ~UCF_SWAPPED;
+ thr->ignore_interceptors++;
+ int ret = getcontext(oucp);
+ if (!(oucp->uc_onstack & UCF_SWAPPED)) {
+ thr->ignore_interceptors--;
+ if (!ret) {
+ oucp->uc_onstack |= UCF_SWAPPED;
+ ret = setcontext(ucp);
+ }
+ }
+ return ret;
+}
+
+// On macOS, libc++ is always linked dynamically, so intercepting works the
+// usual way.
+#define STDCXX_INTERCEPTOR TSAN_INTERCEPTOR
+
+namespace {
+struct fake_shared_weak_count {
+ volatile a64 shared_owners;
+ volatile a64 shared_weak_owners;
+ virtual void _unused_0x0() = 0;
+ virtual void _unused_0x8() = 0;
+ virtual void on_zero_shared() = 0;
+ virtual void _unused_0x18() = 0;
+ virtual void on_zero_shared_weak() = 0;
+};
+} // namespace
+
+// The following code adds libc++ interceptors for:
+// void __shared_weak_count::__release_shared() _NOEXCEPT;
+// bool __shared_count::__release_shared() _NOEXCEPT;
+// Shared and weak pointers in C++ maintain reference counts via atomics in
+// libc++.dylib, which are TSan-invisible, and this leads to false positives in
+// destructor code. These interceptors re-implements the whole functions so that
+// the mo_acq_rel semantics of the atomic decrement are visible.
+//
+// Unfortunately, the interceptors cannot simply Acquire/Release some sync
+// object and call the original function, because it would have a race between
+// the sync and the destruction of the object. Calling both under a lock will
+// not work because the destructor can invoke this interceptor again (and even
+// in a different thread, so recursive locks don't help).
+
+STDCXX_INTERCEPTOR(void, _ZNSt3__119__shared_weak_count16__release_sharedEv,
+ fake_shared_weak_count *o) {
+ if (!flags()->shared_ptr_interceptor)
+ return REAL(_ZNSt3__119__shared_weak_count16__release_sharedEv)(o);
+
+ SCOPED_TSAN_INTERCEPTOR(_ZNSt3__119__shared_weak_count16__release_sharedEv,
+ o);
+ if (__tsan_atomic64_fetch_add(&o->shared_owners, -1, mo_release) == 0) {
+ Acquire(thr, pc, (uptr)&o->shared_owners);
+ o->on_zero_shared();
+ if (__tsan_atomic64_fetch_add(&o->shared_weak_owners, -1, mo_release) ==
+ 0) {
+ Acquire(thr, pc, (uptr)&o->shared_weak_owners);
+ o->on_zero_shared_weak();
+ }
+ }
+}
+
+STDCXX_INTERCEPTOR(bool, _ZNSt3__114__shared_count16__release_sharedEv,
+ fake_shared_weak_count *o) {
+ if (!flags()->shared_ptr_interceptor)
+ return REAL(_ZNSt3__114__shared_count16__release_sharedEv)(o);
+
+ SCOPED_TSAN_INTERCEPTOR(_ZNSt3__114__shared_count16__release_sharedEv, o);
+ if (__tsan_atomic64_fetch_add(&o->shared_owners, -1, mo_release) == 0) {
+ Acquire(thr, pc, (uptr)&o->shared_owners);
+ o->on_zero_shared();
+ return true;
+ }
+ return false;
+}
+
+namespace {
+struct call_once_callback_args {
+ void (*orig_func)(void *arg);
+ void *orig_arg;
+ void *flag;
+};
+
+void call_once_callback_wrapper(void *arg) {
+ call_once_callback_args *new_args = (call_once_callback_args *)arg;
+ new_args->orig_func(new_args->orig_arg);
+ __tsan_release(new_args->flag);
+}
+} // namespace
+
+// This adds a libc++ interceptor for:
+// void __call_once(volatile unsigned long&, void*, void(*)(void*));
+// C++11 call_once is implemented via an internal function __call_once which is
+// inside libc++.dylib, and the atomic release store inside it is thus
+// TSan-invisible. To avoid false positives, this interceptor wraps the callback
+// function and performs an explicit Release after the user code has run.
+STDCXX_INTERCEPTOR(void, _ZNSt3__111__call_onceERVmPvPFvS2_E, void *flag,
+ void *arg, void (*func)(void *arg)) {
+ call_once_callback_args new_args = {func, arg, flag};
+ REAL(_ZNSt3__111__call_onceERVmPvPFvS2_E)(flag, &new_args,
+ call_once_callback_wrapper);
+}
+
+} // namespace __tsan
+
+#endif // SANITIZER_MAC