Says GCC 12 with -sanitize address -sanitize undefined:
qfontengine.cpp: In member function ‘bool QFontEngine::processHheaTable() const’:
qfontengine.cpp:386:65: error: array subscript 4 is outside array bounds of ‘const char [1]’ [-Werror=array-bounds]
386 | qint16 ascent = qFromBigEndian<qint16>(hhea.constData() + 4);
| ~~~~~~~~~~~~~~~~~^~~
qbytearray.h:56:23: note: at offset 4 into object ‘QByteArray::_empty’ of size 1
56 | static const char _empty;
| ^~~~~~
(repeats several times)
The compiler apparently assumes that data() and size() are independent
of each other, and so finds that that constData() may return &_empty,
which is a const char[1].
For some reason, storing the result of constData() in a temporary and
indexing off of that fixes the issue.
Potentially adding Q_ASSUME(d.data()[d.size] == '\0'); in some
strategic place would fix it, too, but would incur runtime overhead.
See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105348
Task-number: QTBUG-103923
Pick-to: 6.3 6.2
Change-Id: Ia6e24e01d1c2a6bd9d91d4d082df9fba0d5c668f
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Konstantin Ritt <ritt.ks@gmail.com>
7908b0cea6