[TSan] Initialize libdispatch interceptors if necessary

[yln]

Summary

On Linux (and other non-Darwin platforms) we need to initialize interceptors.
Since tsan_libdispatch.cc is compiled optionally, add a weak default implementation of InitializeLibdispatchInterceptors.

lib/tsan/rtl/tsan_interceptors.cc

 
 #if !SANITIZER_MAC && !SANITIZER_ANDROID
 static void unreachable() {
   Report("FATAL: ThreadSanitizer: unreachable called\n");
   Die();
 }
 #endif
 
+// Define default implementation since interception of libdispatch  is optional.
+SANITIZER_WEAK_ATTRIBUTE void InitializeLibdispatchInterceptors() {}
+
 void InitializeInterceptors() {
 #if !SANITIZER_MAC
   // We need to setup it early, because functions like dlsym() can call it.
   REAL(memset) = internal_memset;
   REAL(memcpy) = internal_memcpy;
 #endif
 
   // Instruct libc malloc to consume less memory.
 #if SANITIZER_LINUX
   mallopt(1, 0);  // M_MXFAST
   mallopt(-3, 32*1024);  // M_MMAP_THRESHOLD
 #endif
 
   new(interceptor_ctx()) InterceptorContext();
 
   InitializeCommonInterceptors();
   InitializeSignalInterceptors();
+  InitializeLibdispatchInterceptors();
 
 #if !SANITIZER_MAC
   // We can not use TSAN_INTERCEPT to get setjmp addr,
   // because it does &setjmp and setjmp is not present in some versions of libc.
   using __interception::GetRealFunctionAddress;
   GetRealFunctionAddress(TSAN_STRING_SETJMP,
                          (uptr*)&REAL(setjmp_symname), 0, 0);
   GetRealFunctionAddress("_setjmp", (uptr*)&REAL(_setjmp), 0, 0);

lib/tsan/rtl/tsan_libdispatch.cc

 // executions of blocks in that queue.
 TSAN_INTERCEPTOR(void, dispatch_resume, dispatch_object_t o) {
   SCOPED_TSAN_INTERCEPTOR(dispatch_resume, o);
   Release(thr, pc, (uptr)o);  // Synchronizes with the Acquire() on serial_sync
                               // in dispatch_sync_pre_execute
   return REAL(dispatch_resume)(o);
 }
 
+void InitializeLibdispatchInterceptors() {
+  INTERCEPT_FUNCTION(dispatch_async);
+  INTERCEPT_FUNCTION(dispatch_async_f);
+  INTERCEPT_FUNCTION(dispatch_sync);
+  INTERCEPT_FUNCTION(dispatch_sync_f);
+  INTERCEPT_FUNCTION(dispatch_barrier_async);
+  INTERCEPT_FUNCTION(dispatch_barrier_async_f);
+  INTERCEPT_FUNCTION(dispatch_barrier_sync);
+  INTERCEPT_FUNCTION(dispatch_barrier_sync_f);
+  INTERCEPT_FUNCTION(dispatch_after);
+  INTERCEPT_FUNCTION(dispatch_after_f);
+  INTERCEPT_FUNCTION(dispatch_once);
+  INTERCEPT_FUNCTION(dispatch_once_f);
+  INTERCEPT_FUNCTION(dispatch_semaphore_signal);
+  INTERCEPT_FUNCTION(dispatch_semaphore_wait);
+  INTERCEPT_FUNCTION(dispatch_group_wait);
+  INTERCEPT_FUNCTION(dispatch_group_leave);
+  INTERCEPT_FUNCTION(dispatch_group_async);
+  INTERCEPT_FUNCTION(dispatch_group_async_f);
+  INTERCEPT_FUNCTION(dispatch_group_notify);
+  INTERCEPT_FUNCTION(dispatch_group_notify_f);
+  INTERCEPT_FUNCTION(dispatch_source_set_event_handler);
+  INTERCEPT_FUNCTION(dispatch_source_set_event_handler_f);
+  INTERCEPT_FUNCTION(dispatch_source_set_cancel_handler);
+  INTERCEPT_FUNCTION(dispatch_source_set_cancel_handler_f);
+  INTERCEPT_FUNCTION(dispatch_source_set_registration_handler);
+  INTERCEPT_FUNCTION(dispatch_source_set_registration_handler_f);
+  INTERCEPT_FUNCTION(dispatch_apply);
+  INTERCEPT_FUNCTION(dispatch_apply_f);
+  INTERCEPT_FUNCTION(dispatch_data_create);
+  INTERCEPT_FUNCTION(dispatch_read);
+  INTERCEPT_FUNCTION(dispatch_write);
+  INTERCEPT_FUNCTION(dispatch_io_read);
+  INTERCEPT_FUNCTION(dispatch_io_write);
+  INTERCEPT_FUNCTION(dispatch_io_barrier);
+  INTERCEPT_FUNCTION(dispatch_io_create);
+  INTERCEPT_FUNCTION(dispatch_io_create_with_path);
+  INTERCEPT_FUNCTION(dispatch_io_create_with_io);
+  INTERCEPT_FUNCTION(dispatch_io_close);
+  INTERCEPT_FUNCTION(dispatch_resume);
+}
+
 }  // namespace __tsan