[PATCH] [AArch64] Mark single precision pseudo registers unavailable if invalid

[Yao Qi]

Pierre Langlois <pierre.langlois@arm.com> writes:

> It turns out GDB does not check if S registers are valid before returning
> a value for them.  It should return <unavailable> in this case.

Yes, your fix is correct, however ...

>
> Thanks,
> Pierre
>
> gdb/ChangeLog:
>
> 	* aarch64-tdep.c (aarch64_pseudo_read_value): Mark S register as
> 	unavailable if invalid.

... when I read your patch, I am wondering why does aarch64 implement
gdbarch method pseudo_register_read_value rather than
pseudo_register_read.  If we implement the pseudo_register_read, the
caller will mark the value unavailable according to its return value.
pseudo_register_read_value was added to handle partially available
registers by https://sourceware.org/ml/gdb-patches/2011-07/msg00351.html
but I don't think of a case that some aarch64 register is partially
available.  Maybe, another fix to this problem is to implement
pseudo_register_read instead of pseudo_register_read_value.

-- 
Yao (齐尧)