From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 2951 invoked by alias); 7 Jul 2009 09:45:17 -0000 Received: (qmail 2941 invoked by uid 22791); 7 Jul 2009 09:45:15 -0000 X-SWARE-Spam-Status: No, hits=-2.5 required=5.0 tests=AWL,BAYES_00 X-Spam-Check-By: sourceware.org Received: from sibelius.xs4all.nl (HELO sibelius.xs4all.nl) (82.92.89.47) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Tue, 07 Jul 2009 09:45:08 +0000 Received: from brahms.sibelius.xs4all.nl (kettenis@localhost [127.0.0.1]) by brahms.sibelius.xs4all.nl (8.14.3/8.14.3) with ESMTP id n679hR1e008475; Tue, 7 Jul 2009 11:43:27 +0200 (CEST) Received: (from kettenis@localhost) by brahms.sibelius.xs4all.nl (8.14.3/8.14.3/Submit) id n679hRt8029389; Tue, 7 Jul 2009 11:43:27 +0200 (CEST) Date: Tue, 07 Jul 2009 09:45:00 -0000 Message-Id: <200907070943.n679hRt8029389@brahms.sibelius.xs4all.nl> From: Mark Kettenis To: gingold@adacore.com CC: gdb-patches@sourceware.org In-reply-to: (message from Tristan Gingold on Tue, 7 Jul 2009 10:52:15 +0200) Subject: Re: [RFA Darwin]: handle simultaneous signal posting and single-stepping References: 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: 2009-07/txt/msg00185.txt.bz2 > From: Tristan Gingold > Date: Tue, 7 Jul 2009 10:52:15 +0200 > > Hi, > > in some cases (when a signal was received when the execution was > stopped on a breakpoint), gdb resumes the > inferior with both step=1 and signal != 0. This case wasn't handled > correctly by darwin-nat (as the native > API isn't able to do that). > > This patch fixes the issue by first single-stepping and keeping in > mind that a signal has to be posted. I'm not sure that single-stepping before sending the signal is right. This means we'll execute an instruction (which potentially affects the way signals are handled) before the program actually sees the signal. I think a better way to do this is to continue with a signal while keeping the breakpoints inserted, and deal with hitting the breakpoint again in the appropriate way. Also, I think this needs to be handled in the generic code. I'm facing the same problem on OpenBSD. > 2009-07-07 Tristan Gingold > > * darwin-nat.c (darwin_resume_thread): Handle simultaneous single-step > and signal. > * darwin-nat.h (struct private_thread_info): Add signal_to_send field. > Improve comment. > > > Index: darwin-nat.c > =================================================================== > RCS file: /cvs/src/src/gdb/darwin-nat.c,v > retrieving revision 1.13 > diff -u -p -r1.13 darwin-nat.c > --- darwin-nat.c 22 Jun 2009 08:24:29 -0000 1.13 > +++ darwin-nat.c 7 Jul 2009 08:50:45 -0000 > @@ -640,6 +640,19 @@ darwin_resume_thread (struct inferior *i > (3, _("darwin_resume_thread: state=%d, thread=0x%x, step=%d > nsignal=%d\n"), > thread->msg_state, thread->gdb_port, step, nsignal); > > + if (step && nsignal) > + { > + /* We can't handle this in one step. The expected behaviour is > single > + step first and then post the signal. */ > + thread->signal_to_send = nsignal; > + nsignal = 0; > + } > + else if (thread->signal_to_send && !step) > + { > + nsignal = thread->signal_to_send; > + thread->signal_to_send = 0; > + } > + > switch (thread->msg_state) > { > case DARWIN_MESSAGE: > Index: darwin-nat.h > =================================================================== > RCS file: /cvs/src/src/gdb/darwin-nat.h,v > retrieving revision 1.3 > diff -u -p -r1.3 darwin-nat.h > --- darwin-nat.h 19 Jun 2009 14:30:30 -0000 1.3 > +++ darwin-nat.h 7 Jul 2009 08:50:45 -0000 > @@ -80,9 +80,13 @@ struct private_thread_info > /* True if this thread is single-stepped. */ > unsigned char single_step; > > - /* True if a signal was manually sent to the thread. */ > + /* True if a signal was manually sent to the thread. In this case, > we don't > + report that a signal was posted. */ > unsigned char signaled; > > + /* Signal to be sent. Used to handle simultaneous step and > signal. */ > + unsigned char signal_to_send; > + > /* The last exception received. */ > struct darwin_exception_msg event; > }; > >