[tsan] Avoid false positives with GCD data callbacks
This patch adds synchronization between the creation of the GCD data object and destructor’s execution. It’s far from perfect, because ideally we’d want to synchronize the destruction of the last reference (via dispatch_release) and the destructor’s execution, but intercepting objc_release is problematic.
Differential Revision: http://reviews.llvm.org/D21990
git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@274749 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/tsan/rtl/tsan_libdispatch_mac.cc b/lib/tsan/rtl/tsan_libdispatch_mac.cc
index cde5ed0..15805b9 100644
--- a/lib/tsan/rtl/tsan_libdispatch_mac.cc
+++ b/lib/tsan/rtl/tsan_libdispatch_mac.cc
@@ -475,6 +475,32 @@
WRAP(dispatch_apply)(iterations, queue, new_block);
}
+DECLARE_REAL_AND_INTERCEPTOR(void, free, void *ptr)
+DECLARE_REAL_AND_INTERCEPTOR(int, munmap, void *addr, long_t sz)
+
+TSAN_INTERCEPTOR(dispatch_data_t, dispatch_data_create, const void *buffer,
+ size_t size, dispatch_queue_t q, dispatch_block_t destructor) {
+ SCOPED_TSAN_INTERCEPTOR(dispatch_data_create, buffer, size, q, destructor);
+ if ((q == nullptr) || (destructor == DISPATCH_DATA_DESTRUCTOR_DEFAULT))
+ return REAL(dispatch_data_create)(buffer, size, q, destructor);
+
+ if (destructor == DISPATCH_DATA_DESTRUCTOR_FREE)
+ destructor = ^(void) { WRAP(free)((void *)buffer); };
+ else if (destructor == DISPATCH_DATA_DESTRUCTOR_MUNMAP)
+ destructor = ^(void) { WRAP(munmap)((void *)buffer, size); };
+
+ SCOPED_TSAN_INTERCEPTOR_USER_CALLBACK_START();
+ dispatch_block_t heap_block = Block_copy(destructor);
+ SCOPED_TSAN_INTERCEPTOR_USER_CALLBACK_END();
+ tsan_block_context_t *new_context =
+ AllocContext(thr, pc, q, heap_block, &invoke_and_release_block);
+ uptr submit_sync = (uptr)new_context;
+ Release(thr, pc, submit_sync);
+ return REAL(dispatch_data_create)(buffer, size, q, ^(void) {
+ dispatch_callback_wrap(new_context);
+ });
+}
+
} // namespace __tsan
#endif // SANITIZER_MAC
diff --git a/test/tsan/Darwin/gcd-data.mm b/test/tsan/Darwin/gcd-data.mm
new file mode 100644
index 0000000..a5154dc
--- /dev/null
+++ b/test/tsan/Darwin/gcd-data.mm
@@ -0,0 +1,36 @@
+// RUN: %clang_tsan %s -o %t -framework Foundation
+// RUN: %env_tsan_opts=ignore_interceptors_accesses=1 %run %t 2>&1 | FileCheck %s
+
+#import <Foundation/Foundation.h>
+
+long global;
+
+int main(int argc, const char *argv[]) {
+ fprintf(stderr, "Hello world.\n");
+
+ dispatch_queue_t q = dispatch_queue_create("my.queue", DISPATCH_QUEUE_SERIAL);
+ dispatch_semaphore_t sem = dispatch_semaphore_create(0);
+
+ global = 44;
+ dispatch_data_t data = dispatch_data_create("buffer", 6, q, ^{
+ fprintf(stderr, "Data destructor.\n");
+ global++;
+
+ dispatch_semaphore_signal(sem);
+ });
+ dispatch_release(data);
+ data = nil;
+
+ dispatch_semaphore_wait(sem, DISPATCH_TIME_FOREVER);
+
+ data = dispatch_data_create("buffer", 6, q, DISPATCH_DATA_DESTRUCTOR_DEFAULT);
+ dispatch_release(data);
+ data = nil;
+
+ fprintf(stderr, "Done.\n");
+}
+
+// CHECK: Hello world.
+// CHECK: Data destructor.
+// CHECK-NOT: WARNING: ThreadSanitizer
+// CHECK: Done.
