From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from [140.186.70.92] (port=45617 helo=eggs.gnu.org)
	by lists.gnu.org with esmtp (Exim 4.43) id 1P5Ljt-0007Ua-Ju
	for qemu-devel@nongnu.org; Mon, 11 Oct 2010 13:00:42 -0400
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <armbru@redhat.com>) id 1P5Ljr-0003R4-PE
	for qemu-devel@nongnu.org; Mon, 11 Oct 2010 13:00:41 -0400
Received: from mx1.redhat.com ([209.132.183.28]:42291)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <armbru@redhat.com>) id 1P5Ljr-0003Qi-J9
	for qemu-devel@nongnu.org; Mon, 11 Oct 2010 13:00:39 -0400
From: Markus Armbruster <armbru@redhat.com>
Subject: Re: [Qemu-devel] [PATCH 03/12] eepro100: initialize a variable in
	all	cases
References: <AANLkTim-7Pj=S+pCDD-knA=usWoCWZjVxZBm9ughfVYZ@mail.gmail.com>
	<m3ocb093wd.fsf@blackfin.pond.sub.org>
	<4CB3364D.4010707@mail.berlios.de>
Date: Mon, 11 Oct 2010 19:00:31 +0200
In-Reply-To: <4CB3364D.4010707@mail.berlios.de> (Stefan Weil's message of
	"Mon, 11 Oct 2010 18:07:41 +0200")
Message-ID: <m3bp70zmts.fsf@blackfin.pond.sub.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
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.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: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Stefan Weil <weil@mail.berlios.de>
Cc: Blue Swirl <blauwirbel@gmail.com>, qemu-devel <qemu-devel@nongnu.org>

Stefan Weil <weil@mail.berlios.de> writes:

> Am 11.10.2010 16:53, schrieb Markus Armbruster:
>> Blue Swirl <blauwirbel@gmail.com> writes:
>>
>>> Compiling with GCC 4.6.0 20100925 produced warnings:
>>> /src/qemu/hw/eepro100.c: In function 'eepro100_read4':
>>> /src/qemu/hw/eepro100.c:1351:14: error: 'val' may be used
>>> uninitialized in this function [-Werror=uninitialized]
>>> /src/qemu/hw/eepro100.c: In function 'eepro100_read2':
>>> /src/qemu/hw/eepro100.c:1328:14: error: 'val' may be used
>>> uninitialized in this function [-Werror=uninitialized]
>>> /src/qemu/hw/eepro100.c: In function 'eepro100_read1':
>>> /src/qemu/hw/eepro100.c:1285:13: error: 'val' may be used
>>> uninitialized in this function [-Werror=uninitialized]
>>>
>>> Fix by initializing 'val' at start.
>>
>> I don't like sweeping bugs under the carpet like that. The initial
>> value is used when and only when the emulation is buggy. We doubt it
>> can happen. If we truly believe it can't happen, assert it. If we just
>> doubt it, log it.
>
> Markus, that patch would only be an intermediate solution
> which helps to fix a certain class of compiler warnings.
>
> I already promised to test the code with assertions
> and started doing so (see my qemu repository
> http://repo.or.cz/w/qemu/ar7.git/history/HEAD:/hw/eepro100.c).
> Testing takes some time, so the intermediate solution
> can be reasonable.
>
> But nothing will be swept under the carpet!

An intermediate solution could use a comment, but as long as you take
care of the real solution, it's not that important.