There's enough space in the LSB of the three pointers to encode the
type.
Saves sizeof(void*) in the Private class, but, more importantly, paves
the way for the next patch to get rid of the Private class and its
memory allocation altogether, turning QEventLoopLocker::d_ptr into
what this patch still calls QEventLoopLockerPrivate::p.
Neither QTaggedPointer nor QML's QBiPointer apply here. QTaggedPointer
only supports a single T, plus flags; QBiPointer supports only two Ts,
and one flag; we need three Ts and no flags. This could be a
QVariantPointer<QEventLoopPrivate, QCoreApplicationPriivate*, QThreadPrivate*>
I'm thinking about it; just would want to find a second use-case for it.
Task-number: QTBUG-114793
Pick-to: 6.6
Change-Id: I0e21bd8745cc75a9c04b71343c398ad953283857
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
c70257e9b2