This avoids crashes accessing deleted memory when creating a QObject
after the last QObject had been deleted, like a qDebug() in global
destructors.
==41000== Invalid read of size 4
==41000== at 0x5F01ED5: bool QBasicAtomicOps<4>::ref<int>(int&) (qatomic_x86.h:208)
==41000== by 0x5F01309: QBasicAtomicInteger<int>::ref() (qbasicatomic.h:147)
==41000== by 0x5F24051: QThreadData::ref() (qthread.cpp:100)
==41000== by 0x614A984: QObject::QObject(QObject*) (qobject.cpp:681)
==41000== Address 0x6ee73f0 is 0 bytes inside a block of size 152 free'd
==41000== at 0x4A0736C: operator delete(void*) (vg_replace_malloc.c:480)
==41000== by 0x5F240BF: QThreadData::deref() (qthread.cpp:109)
==41000== by 0x6113F6B: QCoreApplicationData::~QCoreApplicationData() (qcoreapplication.cpp:268)
The comment right above the change in qthread.cpp looks eerily similar
to the problem I'm trying to fix. However, the actual change that
introduced the change is not in the Qt public history, so we can't
know for sure what the problem was then.
Change-Id: I0dba895b041fe6cf81e6f8939ca85035cd00aad1
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>
950b35cf97