ada-lang.c is a bit too eager trying to decode unions in the Ada style
-- looking for discriminants and such. This causes crashes when
printing a non-Ada union in Ada mode, something that can easily happen
when printing a value from history or certain registers on AArch64.
This patch fixes the bug by changing ada-lang.c to only apply special
Ada treatment to types coming from an Ada CU. This in turn required a
couple of surprising changes.
First, some of the Ada code was already using HAVE_GNAT_AUX_INFO to
decide whether a type had already been fixed -- such types had
INIT_CPLUS_SPECIFIC called on them. This patch changes these spots to
use the "none" identifier instead.
This then required changing value_rtti_type to avoid changing the
language-specific object attached to an Ada type, which seems like a
good change regardless.
Tested on x86-64 Fedora 29.
gdb/ChangeLog
2019-04-19 Tom Tromey <tromey@adacore.com>