QAbstractEventDispatcher: don't recreate QThreadData if it is goneHEADdev

Since QAbstractEventDispatcher is a QObject, the base class construction
will necessarily have created a QThreadData, if one didn't exist yet.
Normally, this means the QThreadData reference count shouldn't have gone
down to zero if the dispatcher still exists. However, the thread-local
pointer in qthread_{unix,cpp}.cpp may have already been reset, even if
we haven't reached a zero count. This commit makes it so we don't
recreate the QThreadData under those conditions.

It's also a minor performance optimization, by suppressing the need to
call QThreadData::createCurrentThreadData(). It may additionally fix
some issues with calling pthread_setspecific() / TlsSetValue() in very
late thread execution.

Task-number: QTBUG-137130
Task-number: QTBUG-136629
Pick-to: 6.10 6.9 6.8
Change-Id: Ie88d88cfaa5330cdca79fffded47ecb2bb4113c1
Reviewed-by: Fabian Kosmale <[email protected]>
Reviewed-by: Volker Hilsheimer <[email protected]>

0 files changed, 0 insertions, 0 deletions