Re: continuations and breakpoint commands

[Pedro Alves <pedro at codesourcery dot com>]

A Friday 02 May 2008 16:38:26, Daniel Jacobowitz wrote:
> On Tue, Apr 29, 2008 at 10:21:52PM +0100, Pedro Alves wrote:
> > 2008-04-29  Pedro Alves  <pedro@codesourcery.com>
> >
> > 	* inf-loop.c (inferior_event_handler): Run all continuations and
> > 	print any language change before running the breakpoint commands.
>
> Looks OK, unless it needs to be reworked after the discussion we're
> currently having about what happens to other continuations.

Since we are not going to add per-thread continuations in all-stop mode
after all, I've checked this in, after another round of testing.

-- 
Pedro Alves

2008-05-06  Pedro Alves  <pedro@codesourcery.com>

	* inf-loop.c (inferior_event_handler): Run all continuations and
	print any language change before running the breakpoint commands.

---
 gdb/inf-loop.c |   33 +++++++++++++++++++--------------
 1 file changed, 19 insertions(+), 14 deletions(-)

Index: src/gdb/inf-loop.c
===================================================================
--- src.orig/gdb/inf-loop.c	2008-05-06 19:23:15.000000000 +0100
+++ src/gdb/inf-loop.c	2008-05-06 19:23:52.000000000 +0100
@@ -92,30 +92,35 @@ inferior_event_handler (enum inferior_ev
       was_sync = sync_execution;
       async_enable_stdin ();
 
-      /* If there's an error doing breakpoint commands, we don't
-	 want to throw -- continuation might still do something.  */
-      TRY_CATCH (e, RETURN_MASK_ALL)
-	{
-	  bpstat_do_actions (&stop_bpstat);
-	}
       /* If we were doing a multi-step (eg: step n, next n), but it
 	 got interrupted by a breakpoint, still do the pending
 	 continuations.  The continuation itself is responsible for
-	 distinguishing the cases.  */
+	 distinguishing the cases.  The continuations are allowed to
+	 touch the inferior memory, e.g. to remove breakpoints, so run
+	 them before running breakpoint commands, which may resume the
+	 target.  */
       do_all_intermediate_continuations (0);
 
+      /* Always finish the previous command before running any
+	 breakpoint commands.  Any stop cancels the previous command.
+	 E.g. a "finish" or "step-n" command interrupted by an
+	 unrelated breakpoint is canceled.  */
       do_all_continuations (0);
 
-      if (current_language != expected_language)
+      if (current_language != expected_language
+	  && language_mode == language_mode_auto)
+	language_info (1);	/* Print what changed.  */
+
+      /* Don't propagate breakpoint commands errors.  Either we're
+	 stopping or some command resumes the inferior.  The user will
+	 be informed.  */
+      TRY_CATCH (e, RETURN_MASK_ALL)
 	{
-	  if (language_mode == language_mode_auto)
-	    {
-	      language_info (1);	/* Print what changed.  */
-	    }
+	  bpstat_do_actions (&stop_bpstat);
 	}
 
-      /* If the continuation did not start the target again,
-	 prepare for interation with the user.  */
+      /* If no breakpoint command resumed the inferior, prepare for
+	 interaction with the user.  */
       if (!target_executing)
 	{              
 	  if (was_sync)