Re: [PATCH, updated] Add support for setting disassembler-options in GDB for POWER, ARM and S390

[Yao Qi <qiyaoltc at gmail dot com>]

Peter Bergner <bergner@vnet.ibm.com> writes:

Hi Peter,
> @@ -3257,27 +3262,26 @@ static bfd_vma ifthen_address;
>  int
>  get_arm_regname_num_options (void)
>  {
> -  return NUM_ARM_REGNAMES;
> -}
> +  static int num_opts = 0;
>  
> -int
> -set_arm_regname_option (int option)
> -{
> -  int old = regname_selected;
> -  regname_selected = option;
> -  return old;
> +  if (num_opts == 0)
> +    {
> +      unsigned int i;
> +      for (i = 0; i < NUM_ARM_OPTIONS; i++)
> +	if (CONST_STRNEQ (regnames[i].name, "reg-names-"))
> +	  num_opts++;
> +    }
> +
> +  return num_opts;
>  }

Function get_arm_regname_num_options is only used in gdb.  Since we've
have disassembler_options_arm, we can use it in gdb and remove
get_arm_regname_num_options.

We use get_arm_regname_num_options in arm-tdep.c,

   /* Get the number of possible sets of register names defined in opcodes.  */
   num_disassembly_options = get_arm_regname_num_options ();

We can get 'num_disassembly_options' by iterating options from
disassembler_options_arm.

>  
> -int
> +void
>  get_arm_regnames (int option,
>  		  const char **setname,
> -		  const char **setdescription,
> -		  const char *const **register_names)
> +		  const char **setdescription)
>  {
> -  *setname = regnames[option].name;
> -  *setdescription = regnames[option].description;
> -  *register_names = regnames[option].reg_names;
> -  return 16;
> +  *setname = regnames[option].name + strlen ("reg-names-");
> +  *setdescription = _(regnames[option].description);
>  }
>  

Likewise, we can use disassembler_options_arm in gdb and remove
get_arm_regnames.  We use get_arm_regnames like this in arm-tdep.c,

  for (i = 0; i < num_disassembly_options; i++)
    {
      get_arm_regnames (i, &setname, &setdesc);
      valid_disassembly_styles[i] = setname;
      length = snprintf (rdptr, rest, "%s - %s\n", setname, setdesc);
      rdptr += length;
      rest -= length;
    }

but we can replace it by disassembler_options_arm instead.

> diff --git a/gdb/gdbarch.sh b/gdb/gdbarch.sh
> index 54549b6..c607853 100755
> --- a/gdb/gdbarch.sh
> +++ b/gdb/gdbarch.sh
> @@ -1163,6 +1163,10 @@ m:const char *:gnu_triplet_regexp:void:::default_gnu_triplet_regexp::0
>  # each address in memory.
>  m:int:addressable_memory_unit_size:void:::default_addressable_memory_unit_size::0
>  
> +# Functions for allowing a target to modify its disassembler options.
> +v:char *:disassembler_options:::0:0::0:pstring (gdbarch->disassembler_options)

These options should be modeled as per-architecture data.  We need to
define a key to access that data dynamically.  grep
"static struct gdbarch_data *" in *.c.

> +v:const disasm_options_t *:disassembler_options_arch:::0:0::0:host_address_to_string (gdbarch->disassembler_options_arch->name)

disassembler_options_arch is not clear to me, and I feel
gdbarch_disassembler_options_arch is even worse.  How about renaming it
to "disassembler_options_supported" or "valid_disassembler_options"?

-- 
Yao (齐尧)