Re: patch for info threads problem with target arm-elf (PR 1199).

[Andrew Cagney <ac131313 at redhat dot com>]

> On Fri, Jul 25, 2003 at 05:26:12PM -0700, Michael Snyder wrote:
>
> > Andrea Michelotti wrote:
>
> > >-----------------------
> > >Andrea Michelotti
> > >HW/SW Co-Design Manager
> > >IPITEC (ATMEL)
>
> > I think it can be approved.  Do you have an FSF copyright assignment?
>
>
> I'd want to ping Andrew about this first before scattering NULL pointer
> checks - Andrew, does "there is always a frame" include when the
> inferior does not exist yet?

Kind of :-)  If the inferior doesn't exist, GDB should never get to find 
out the answer.  See get_current_frame and all those error() checks.

> Also, I think a better solution to this actual crash is for info
> threads to bail out early if we don't have an inferior.  Probably
> target_has_registers ().

Yes, looking at the start of info_threads_command:

> static void
> info_threads_command (char *arg, int from_tty)
> {
>   struct thread_info *tp;
>   ptid_t current_ptid;
>   struct frame_info *cur_frame;
>   int saved_frame_level = frame_relative_level (deprecated_selected_frame);
>   int counter;
>   char *extra_info;
>
>   /* Avoid coredumps which would happen if we tried to access a NULL
>      deprecated_selected_frame.  */
>   if (!target_has_stack)
>     error ("No stack.");

The references to:

	deprecated_selected_frame

should have set off alarm bells!

A quick fix would be to call get_selected_frame() (and delete that error 
check).

The correct fix involves per-thread frames ...

Andrew