From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43)
	id 1NrFYD-0007Tc-Ou
	for qemu-devel@nongnu.org; Mon, 15 Mar 2010 15:02:05 -0400
Received: from [199.232.76.173] (port=38846 helo=monty-python.gnu.org)
	by lists.gnu.org with esmtp (Exim 4.43) id 1NrFYD-0007TI-DI
	for qemu-devel@nongnu.org; Mon, 15 Mar 2010 15:02:05 -0400
Received: from Debian-exim by monty-python.gnu.org with spam-scanned (Exim
	4.60) (envelope-from <blauwirbel@gmail.com>) id 1NrFYA-00040Z-Q1
	for qemu-devel@nongnu.org; Mon, 15 Mar 2010 15:02:05 -0400
Received: from mail-pw0-f45.google.com ([209.85.160.45]:44213)
	by monty-python.gnu.org with esmtp (Exim 4.60)
	(envelope-from <blauwirbel@gmail.com>) id 1NrFYA-00040V-Gh
	for qemu-devel@nongnu.org; Mon, 15 Mar 2010 15:02:02 -0400
Received: by pwi9 with SMTP id 9so2080700pwi.4
	for <qemu-devel@nongnu.org>; Mon, 15 Mar 2010 12:02:01 -0700 (PDT)
MIME-Version: 1.0
In-Reply-To: <4B9E7D6F.4000702@redhat.com>
References: <f43fc5581003130656j408f64bfp7fe4bf486c625624@mail.gmail.com>
	<m3sk82nj16.fsf@blackfin.pond.sub.org>
	<f43fc5581003151023g354dc74cr989f3373f5f1de9a@mail.gmail.com>
	<4B9E7A29.1020902@redhat.com>
	<f43fc5581003151126m6a857c57vd16935b6f98a6f07@mail.gmail.com>
	<4B9E7D6F.4000702@redhat.com>
Date: Mon, 15 Mar 2010 21:02:01 +0200
Message-ID: <f43fc5581003151202w71de2b8as5db584a2f3163552@mail.gmail.com>
From: Blue Swirl <blauwirbel@gmail.com>
Content-Type: text/plain; charset=UTF-8
Subject: [Qemu-devel] Re: [PATCH,
	RFC] Replace assert(0) with abort() or cpu_abort()
List-Id: qemu-devel.nongnu.org
List-Unsubscribe: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.gnu.org/pipermail/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Markus Armbruster <armbru@redhat.com>, qemu-devel <qemu-devel@nongnu.org>

On 3/15/10, Paolo Bonzini <pbonzini@redhat.com> wrote:
> >
> > > I'd consider not changing assert(0)->abort()
> > > if there is code after the assert that looks like an attempt at
> recovering.
> > > Example:
> > >
> > >    if (!p) {
> > >        printf ("the impossible has happened!");
> > >        assert (0);
> > >    }
> > >
> > >    return p->q;
> > >
> > >  should be changed to abort, while
> > >
> > >    if (!p) {
> > >        printf ("the impossible has happened!");
> > >        assert (0);
> > >        return 0;
> > >    }
> > >
> > >    return p->q;
> > >
> > >  should not.
> > >
> >
> > Why not? According to manual page, assert(x) is equal to if (!x) abort().
> > As I mentioned earlier, system emulators don't handle SIGABRT
> >
>
>  ... which won't be generated if !NDEBUG.  Only if the recovery code makes
> sense, of course.  However, my point was that those cases where there is
> recovery code are not no-brainers.

Except that compiling with -DNDEBUG was broken and fixed only recently
with a6c6f76ceb95a0986fd1a36cc30f8241734d20c3. Thus I suspect nobody
uses -DNDEBUG for production builds and the code paths after assert(0)
are untested.