Index: compiler-rt/trunk/lib/tsan/rtl/tsan_interceptors_mac.cc =================================================================== --- compiler-rt/trunk/lib/tsan/rtl/tsan_interceptors_mac.cc +++ compiler-rt/trunk/lib/tsan/rtl/tsan_interceptors_mac.cc @@ -297,18 +297,20 @@ }; } // namespace -// This adds a libc++ interceptor for: +// 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. This interceptor re-implements the whole function so that +// destructor code. These interceptors re-implements the whole functions so that // the mo_acq_rel semantics of the atomic decrement are visible. // -// Unfortunately, this interceptor cannot simply Acquire/Release some sync +// 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) @@ -327,6 +329,20 @@ } } +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); Index: compiler-rt/trunk/test/tsan/Darwin/libcxx-future.mm =================================================================== --- compiler-rt/trunk/test/tsan/Darwin/libcxx-future.mm +++ compiler-rt/trunk/test/tsan/Darwin/libcxx-future.mm @@ -0,0 +1,30 @@ +// RUN: %clangxx_tsan %s -o %t +// RUN: %env_tsan_opts=ignore_interceptors_accesses=1 %run %t 2>&1 | FileCheck %s + +#include +#include +#include + +int main(int argc, const char *argv[]) { + fprintf(stderr, "Hello world.\n"); + + auto my_task = [] { return 42; }; + + std::vector threads; + + for (int i = 0; i < 1000; i++) { + std::packaged_task task(my_task); + std::future future = task.get_future(); + threads.push_back(std::thread(std::move(task))); + } + + for (auto &t : threads) { + t.join(); + } + + fprintf(stderr, "Done.\n"); +} + +// CHECK: Hello world. +// CHECK-NOT: WARNING: ThreadSanitizer +// CHECK: Done.