From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([140.186.70.92]:33092)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <sw@weilnetz.de>) id 1RJ6SQ-0002kK-Ih
	for qemu-devel@nongnu.org; Wed, 26 Oct 2011 12:36:03 -0400
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <sw@weilnetz.de>) id 1RJ6SP-0002pm-Bg
	for qemu-devel@nongnu.org; Wed, 26 Oct 2011 12:36:02 -0400
Received: from v220110690675601.yourvserver.net ([78.47.199.172]:59479)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <sw@weilnetz.de>) id 1RJ6SP-0002oL-6F
	for qemu-devel@nongnu.org; Wed, 26 Oct 2011 12:36:01 -0400
Message-ID: <4EA836BC.40409@weilnetz.de>
Date: Wed, 26 Oct 2011 18:35:08 +0200
From: Stefan Weil <sw@weilnetz.de>
MIME-Version: 1.0
References: <1319487523-19978-1-git-send-email-sw@weilnetz.de>
	<20111026125431.GC27267@stefanha-thinkpad.localdomain>
In-Reply-To: <20111026125431.GC27267@stefanha-thinkpad.localdomain>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
Subject: Re: [Qemu-devel] [PATCH] Fix compiler warning (always return a
 value), introduce qemu_abort?
List-Id: <qemu-devel.nongnu.org>
List-Unsubscribe: <https://lists.nongnu.org/mailman/options/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.nongnu.org/archive/html/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <https://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Alexander Graf <agraf@suse.de>
Cc: Stefan Hajnoczi <stefanha@gmail.com>, qemu-devel@nongnu.org

Am 26.10.2011 14:54, schrieb Stefan Hajnoczi:
> On Mon, Oct 24, 2011 at 10:18:43PM +0200, Stefan Weil wrote:
>> For compilations with -DNDEBUG, the default case did not return
>> a value which caused a compiler warning.
>>
>> Signed-off-by: Stefan Weil <sw@weilnetz.de>
>> ---
>> hw/ppce500_spin.c | 11 ++++++++---
>> 1 files changed, 8 insertions(+), 3 deletions(-)
>>
>> diff --git a/hw/ppce500_spin.c b/hw/ppce500_spin.c
>> index cccd940..5b5ffe0 100644
>> --- a/hw/ppce500_spin.c
>> +++ b/hw/ppce500_spin.c
>> @@ -168,17 +168,22 @@ static uint64_t spin_read(void *opaque, 
>> target_phys_addr_t addr, unsigned len)
>> {
>> SpinState *s = opaque;
>> uint8_t *spin_p = &((uint8_t*)s->spin)[addr];
>> + uint64_t result = 0;
>>
>> switch (len) {
>> case 1:
>> - return ldub_p(spin_p);
>> + result = ldub_p(spin_p);
>> + break;
>> case 2:
>> - return lduw_p(spin_p);
>> + result = lduw_p(spin_p);
>> + break;
>> case 4:
>> - return ldl_p(spin_p);
>> + result = ldl_p(spin_p);
>> + break;
>> default:
>> assert(0);
>
> I would replace assert(3) with abort(3). If this ever happens the
> program is broken - returning 0 instead of an undefined value doesn't
> help.
>
> Stefan

Alex, do you agree on replacing assert() by abort()?

I personally don't like abort() because it does not show the
reason for the failure.

Most users don't know how to get a core dump or how to
use gdb. And even for those who know, a crash caused
by an abort() which cannot be reproduced usually happens
on a system were ulimit disables core dumps...

I'd like to have a qemu_abort() macro in qemu-common.h which
replaces all abort() calls used today:

#define qemu_abort() \
   do { \
     fprintf(stderr, "QEMU aborted in %s, %s:%u\n", __func__, __FILE__, 
__LINE__);
     abort();
   } while (0)

(The macro could also call a function which handles fprintf and abort).

Cheers,
Stefan W.