It was being stored once in QThreadPrivate and once in QThreadData, with
the latter being hidden as a Qt::HANDLE. Besides saving a little bit of
memory, this also solves a small data race condition that arises from
trying to connect a signal to an object moved to that thread and then
emit that signal shortly after the thread starts. Before this patch,
QThreadData::threadId was initialized only by QThreadPrivate::start(),
which meant that we were racing that initialization with this check in
QMetaObject::activate:
const bool receiverInSameThread = currentThreadId == receiver->d_func()->threadData->threadId;
Task-number: QTBUG-52337
Change-Id: Ifea6e497f11a461db432ffff1449ae01f1099aae
Reviewed-by: Olivier Goffart (Woboq GmbH) <ogoffart@woboq.com>
Reviewed-by: Jędrzej Nowacki <jedrzej.nowacki@theqtcompany.com>
112e53fdc4