Re: RFA: [Ada] extract known tasks array parameters from symbol table

[Joel Brobecker <brobecker at adacore dot com>]

Hi Tristan,

> Maybe we should get rid of the fallback, as without debug symbol for
> Ada.Tasking, the whole ada-tasks.c code is pretty useless.

The problem is that certain GNU/Linux distributions decided to simply
strip all runtime libraries of debug info, and then provide additional
packages for the debug version of these shared libs. And apparently,
it's a significant disruption to address this issue at the package
creation level.  So we need to try to support those users the best
we can.

> Manually tested on ia64-hp-openvms.

I'd really like it to be tested on at least a GNU/Linux variant as
well as a bareboard variant using the ravenscar runtime (try the list).
Or, alternatively, put the patch in our tree, and then wait a day or
two to get the results of the nightly testing.

> gdb/
> 2012-02-13  Tristan Gingold  <gingold@adacore.com>
> 
> 	* ada-tasks.c (struct ada_tasks_inferior_data): Add
> 	known_tasks_element and known_tasks_length fields.
> 	(read_known_tasks_array): Change argument type.  Use pointer type
> 	and number of elements from DATA.  Adjust.
> 	(read_known_tasks_list): Likewise.
> 	(get_known_tasks_addr): Change profile.  Try symtab first, and
> 	extract type and size from it.
> 	(ada_set_current_inferior_known_tasks_addr): Adjust for above
> 	change.

Mostly OK.

Just a few thoughts on your patch.

> -/* Return the address of the variable NAME that contains all the known
> -   tasks maintained in the Ada Runtime.  Return NULL if the variable
> -   could not be found, meaning that the inferior program probably does
> -   not use tasking.  */
> +/* Try method KIND to extract known tasks info for DATA.
> +   Return non-zero in case of success, and set the known tasks field of DATA.
> +*/

Nit-picking: Can you fold the last line at around 70 chars?

> -static CORE_ADDR
> -get_known_tasks_addr (const char *name)
> +static int
> +get_known_tasks_addr (struct ada_tasks_inferior_data *data,
> +		      enum ada_known_tasks_kind kind)

For this function, I would like it to be renamed to "get_ada_tasks_info",
"get_inferior_tasks_info", or maybe even "ada_task_info_sniffer".
Something like that.

Also, I am thinking that there is no reason that the caller should
be testing each kind one after the other. I think something like:

    static struct ada_tasks_inferior_data *
    ada_task_info_sniffer (void)
    {
       [lookup array symbol]
       if (symbol)
         {
           [validate]
           return array_info;
         }

       [lookup list symbol]
       if (symbol)
         {
           [validate]
           return list_info;
         }
      [...]

WDYT?

-- 
Joel