Merge remote-tracking branch 'origin/swift-3.1-branch' into stable
* origin/swift-3.1-branch:
Follow-up for r289831: Lower the unjoined thread count to 100 in the libcxx-future.mm testcase.
[tsan] Add interceptor for libcxx __shared_count::__release_shared()
diff --git a/lib/tsan/rtl/tsan_interceptors_mac.cc b/lib/tsan/rtl/tsan_interceptors_mac.cc
index 015e48e..fc5eb04 100644
--- a/lib/tsan/rtl/tsan_interceptors_mac.cc
+++ b/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);
diff --git a/test/tsan/Darwin/libcxx-future.mm b/test/tsan/Darwin/libcxx-future.mm
new file mode 100644
index 0000000..902f267
--- /dev/null
+++ b/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 <iostream>
+#include <future>
+#include <vector>
+
+int main(int argc, const char *argv[]) {
+ fprintf(stderr, "Hello world.\n");
+
+ auto my_task = [] { return 42; };
+
+ std::vector<std::thread> threads;
+
+ for (int i = 0; i < 100; i++) {
+ std::packaged_task<int(void)> task(my_task);
+ std::future<int> 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.
