Re: [PATCH] S390: Fix crash when remote tdesc doesn't define vec128

[Kevin Buettner <kevinb at redhat dot com>]

Hi Andreas,

It needs a ChangeLog entry, but aside from that it looks okay to me.

Kevin

On Thu, 18 Oct 2018 19:54:22 +0200
Andreas Arnez <arnez@linux.ibm.com> wrote:

> I've encountered a GDB crash when trying to read registers from a remote
> stub that provided a target.xml with vector registers, but without the
> 'vec128' data type.  The crash is caused by NULL register type entries for
> the "concatenated" pseudo-registers v0-v15.  These NULL entries are
> introduced by the logic in s390_pseudo_register_type(), where the tdesc
> type 'vec128' is returned unconditionally -- even if it doesn't exist (is
> NULL).
> 
> The fixed logic for determining a "concatenated" vector register's type
> now returns the type of the raw register v16 instead.  This also makes
> sure that all vector register have the same type.
> ---
>  gdb/s390-tdep.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/gdb/s390-tdep.c b/gdb/s390-tdep.c
> index 81fa0329ea..23689aa71a 100644
> --- a/gdb/s390-tdep.c
> +++ b/gdb/s390-tdep.c
> @@ -1275,8 +1275,9 @@ s390_pseudo_register_type (struct gdbarch *gdbarch, int regnum)
>    if (regnum_is_gpr_full (tdep, regnum))
>      return builtin_type (gdbarch)->builtin_uint64;
>  
> +  /* For the "concatenated" vector registers use the same type as v16.  */
>    if (regnum_is_vxr_full (tdep, regnum))
> -    return tdesc_find_type (gdbarch, "vec128");
> +    return tdesc_register_type (gdbarch, S390_V16_REGNUM);
>  
>    internal_error (__FILE__, __LINE__, _("invalid regnum"));
>  }
> -- 
> 2.17.0
>