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

[Daniel Jacobowitz <drow at mvista dot com>]

On Fri, Jul 25, 2003 at 09:26:22PM -0400, Andrew Cagney wrote:
> >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).

Note the access to deprecated_selected_frame above the check :)  OK,
this isn't the thorough fix, but how's this look?  Andrea, does this
work with Eclipse in place of your patch?

-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer

2003-07-25  Daniel Jacobowitz  <drow@mvista.com>

	* thread.c (info_threads_command): Use get_selected_frame ().
	Check that there is at least one non-sentinel frame.

Index: thread.c
===================================================================
RCS file: /cvs/src/src/gdb/thread.c,v
retrieving revision 1.31
diff -u -p -r1.31 thread.c
--- thread.c	5 May 2003 00:27:08 -0000	1.31
+++ thread.c	26 Jul 2003 01:47:08 -0000
@@ -417,14 +417,14 @@ info_threads_command (char *arg, int fro
   struct thread_info *tp;
   ptid_t current_ptid;
   struct frame_info *cur_frame;
-  int saved_frame_level = frame_relative_level (deprecated_selected_frame);
+  int saved_frame_level = frame_relative_level (get_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.");
+  /* Check that there really is a frame.  This happens when a simulator
+     is connected but not loaded or running, for instance.  */
+  if (saved_frame_level < 0)
+    error ("No frame.");
 
   prune_threads ();
   target_find_new_threads ();
@@ -448,10 +448,7 @@ info_threads_command (char *arg, int fro
       puts_filtered ("  ");
 
       switch_to_thread (tp->ptid);
-      if (deprecated_selected_frame)
-	print_stack_frame (deprecated_selected_frame, -1, 0);
-      else
-	printf_filtered ("[No stack.]\n");
+      print_stack_frame (get_selected_frame (), -1, 0);
     }
 
   switch_to_thread (current_ptid);
@@ -463,12 +460,12 @@ info_threads_command (char *arg, int fro
    * of the stack (leaf frame).
    */
   counter = saved_frame_level;
-  cur_frame = find_relative_frame (deprecated_selected_frame, &counter);
+  cur_frame = find_relative_frame (get_selected_frame (), &counter);
   if (counter != 0)
     {
       /* Ooops, can't restore, tell user where we are. */
       warning ("Couldn't restore frame in current thread, at frame 0");
-      print_stack_frame (deprecated_selected_frame, -1, 0);
+      print_stack_frame (get_selected_frame (), -1, 0);
     }
   else
     {