Re: [RFC] s390-tdep.c: Define address class functions for s390x

[Jim Blandy <jimb at redhat dot com>]

This looks like a pretty straightforward definition of a new address
class.  Is that right?

Since we only have one target using this facility at the moment, this
might be premature, but I wonder if it would be worthwhile to provide
standard, table-driven versions of *_address_class_type_flags_to_name,
and *_address_class_name_to_type_flags, so that a target could simply
say:

static address_class_table s390_addr_classes[] = {
  { "mode32", TYPE_FLAG_ADDRESS_CLASS_1 },
  { 0, 0 }
};
...

  use_address_class_table_in_gdbarch (gdbarch, s390_addr_classes);

which would install the right methods.  Or something like that.

Maybe even s390_address_class_type_flags could be handled by the same
table.  I haven't thought it through.

Kevin Buettner <kevinb@redhat.com> writes:

> The default pointer size for s390x is 64 bits.  The patch below causes
> 32-bit pointer types obtained from (dwarf2) debug info to be stored as
> a separate type and to be qualified (in gdb's ptype output) as
> "@mode32".  [Patches to gdbtypes.[hc] and dwarf2read.c which implement
> address class support have already been committed.  They need to be
> revisited, however, because in the course of testing out this patch, I
> found a bug.  More on that later...]
> 
> Comments?
> 
> 	* s390-tdep.c (s390_address_class_type_flags)
> 	(s390_address_class_type_flags_to_name)
> 	(s390_address_class_name_to_type_flags): New functions.
> 	(s390_gdbarch_init): Define ADDRESS_CLASS_TYPE_FLAGS_TO_NAME,
> 	ADDRESS_CLASS_NAME_TO_TYPE_FLAGS, and ADDRESS_CLASS_TYPE_FLAGS.
> 
> Index: s390-tdep.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/s390-tdep.c,v
> retrieving revision 1.70
> diff -u -p -r1.70 s390-tdep.c
> --- s390-tdep.c	8 Jan 2003 17:21:29 -0000	1.70
> +++ s390-tdep.c	27 Jan 2003 23:03:28 -0000
> @@ -1748,6 +1748,37 @@ s390_push_return_address (CORE_ADDR pc, 
>    return sp;
>  }
>  
> +static int
> +s390_address_class_type_flags (int byte_size, int dwarf2_addr_class)
> +{
> +  if (byte_size == 4)
> +    return TYPE_FLAG_ADDRESS_CLASS_1;
> +  else
> +    return 0;
> +}
> +
> +static const char *
> +s390_address_class_type_flags_to_name (struct gdbarch *gdbarch, int type_flags)
> +{
> +  if (type_flags & TYPE_FLAG_ADDRESS_CLASS_1)
> +    return "mode32";
> +  else
> +    return NULL;
> +}
> +
> +int
> +s390_address_class_name_to_type_flags (struct gdbarch *gdbarch, const char *name,
> +				       int *type_flags_ptr)
> +{
> +  if (strcmp (name, "mode32") == 0)
> +    {
> +      *type_flags_ptr = TYPE_FLAG_ADDRESS_CLASS_1;
> +      return 1;
> +    }
> +  else
> +    return 0;
> +}
> +
>  struct gdbarch *
>  s390_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
>  {
> @@ -1869,6 +1900,12 @@ s390_gdbarch_init (struct gdbarch_info i
>        set_gdbarch_long_long_bit (gdbarch, 64);
>        set_gdbarch_ptr_bit (gdbarch, 64);
>        set_gdbarch_register_bytes (gdbarch, S390X_REGISTER_BYTES);
> +      set_gdbarch_address_class_type_flags (gdbarch,
> +                                            s390_address_class_type_flags);
> +      set_gdbarch_address_class_type_flags_to_name (gdbarch,
> +                                                    s390_address_class_type_flags_to_name);
> +      set_gdbarch_address_class_name_to_type_flags (gdbarch,
> +                                                    s390_address_class_name_to_type_flags);
>        break;
>      }
>