Every other export of the C++ runtime is declared APS5_VABI, but these two
were not. On Windows a title calls them with the System V convention while
they read the Microsoft one, so __dynamic_cast took its fourth argument, the
src2dst hint, as the source pointer: an ordinary downcast (hint 0) returned
null, and the negative hints made it read through an invalid pointer.
guest_dynamic_cast calls both through APS5_VABI declarations, as a title
does, and checks a single-inheritance downcast, a failed cross cast, a cast
of a base object and the header __cxa_init_primary_exception fills in.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Rick