From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 30640 invoked by alias); 30 Oct 2008 12:21:58 -0000 Received: (qmail 30628 invoked by uid 22791); 30 Oct 2008 12:21:58 -0000 X-Spam-Check-By: sourceware.org Received: from mail.codesourcery.com (HELO mail.codesourcery.com) (65.74.133.4) by sourceware.org (qpsmtpd/0.31) with ESMTP; Thu, 30 Oct 2008 12:21:55 +0000 Received: (qmail 2923 invoked from network); 30 Oct 2008 12:21:53 -0000 Received: from unknown (HELO orlando.local) (pedro@127.0.0.2) by mail.codesourcery.com with ESMTPA; 30 Oct 2008 12:21:53 -0000 From: Pedro Alves To: gdb-patches@sourceware.org Subject: Re: [Patch] Use resume instead of target_resume when stepping over watchpoint. Date: Thu, 30 Oct 2008 21:21:00 -0000 User-Agent: KMail/1.9.10 Cc: Joel Brobecker , David Daney References: <48C71565.3050601@avtrex.com> <20081030030805.GC3635@adacore.com> In-Reply-To: <20081030030805.GC3635@adacore.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200810301222.23864.pedro@codesourcery.com> X-IsSubscribed: yes Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org X-SW-Source: 2008-10/txt/msg00703.txt.bz2 On Thursday 30 October 2008 03:08:05, Joel Brobecker wrote: > Pedro, Others, > > What do you think of this patch? Personally, I have pretty much > convinced myself that it shouldn't do any harm, but I really > wished that "resume" would take a ptid as an argument. Except > that this is not trivial to do, and I think that the current > "resume" would need to be split a bit, to remove the code that > determines what to resume. Won't this slightly change the behaviour on hardware single-step archs? Before, we'd always tell the target to resume a single-thread (keeping the others stopped, on target that support scheduler locking); with this change, I think you'll tell the target to resume all threads. Urglhs, infrun could use a facelift. The natural function to call would be keep_going instead of resume/prepare_to_wait, but keep_going doesn't know a think about watchpoints... Would setting ecs->event_thread->trap_expected = 1 in addition to switching to resume so we trigger this: resume: if ((step || singlestep_breakpoints_inserted_p) && tp->trap_expected) { ... resume_ptid = inferior_ptid; } be too ugly? Hmmm, maybe not OK, it can have other side effects, like tripping on this... if (ecs->event_thread->stop_signal == TARGET_SIGNAL_TRAP && ecs->event_thread->trap_expected && gdbarch_single_step_through_delay_p (current_gdbarch) && currently_stepping (ecs->event_thread)) { Can you confirm what I think I'm seeing? > > Anyway, I don't see anything wrong with this patch, but I'd love > for someone to take a look as well. This is a pretty delicate > part of the debugger. Do we really need the gdb_assert thought? > > On Tue, Sep 09, 2008 at 05:31:33PM -0700, David Daney wrote: > > In handle_inferior_event() when stepping over a watch point currently we > > issue target_resume(). This only works on architectures that have > > hardware single step support. For gdbarch_software_single_step_p() > > systems (like MIPS), we need to insert a single step breakpoint instead. > > > > The fix is to call resume() as it does the right thing already. I also > > added an assert that inferior_ptid == ecs->ptid to be sure that resume() > > was stepping the proper thread. > > > > This is essentially the change requested by Daniel in: > > http://sourceware.org/ml/gdb-patches/2008-04/msg00443.html > > > > This change is a prerequisite for my forthcoming MIPS hardware watch patch. > > > > Tested on x86_64-pc-linux-gnu as well as mipsel-linux (in conjunction > > with the MIPS hardware watch patch). > > > > OK to commit? > > > > 2008-09-09 David Daney > > > > * infrun.c (handle_inferior_event): Call resume instead of > > target_resume when stepping over watchpoint. > > > > > > > Index: infrun.c > > =================================================================== > > RCS file: /cvs/src/src/gdb/infrun.c,v > > retrieving revision 1.316 > > diff -u -p -r1.316 infrun.c > > --- infrun.c 8 Sep 2008 22:10:20 -0000 1.316 > > +++ infrun.c 9 Sep 2008 23:37:09 -0000 > > @@ -2472,7 +2472,8 @@ targets should add new threads to the th > > if (!HAVE_STEPPABLE_WATCHPOINT) > > remove_breakpoints (); > > registers_changed (); > > - target_resume (ecs->ptid, 1, TARGET_SIGNAL_0); /* Single step */ > > + gdb_assert (ptid_equal (inferior_ptid, ecs->ptid)); > > + resume (1, TARGET_SIGNAL_0); /* Single step */ > > waiton_ptid = ecs->ptid; > > if (HAVE_STEPPABLE_WATCHPOINT) > > infwait_state = infwait_step_watch_state; > > -- Pedro Alves