From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3DB46C606B0 for ; Tue, 9 Jul 2019 05:51:42 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 0B26D20861 for ; Tue, 9 Jul 2019 05:51:41 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0B26D20861 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:46928 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hkj2T-0005PQ-0M for qemu-devel@archiver.kernel.org; Tue, 09 Jul 2019 01:51:41 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:53306) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hkj1b-0004w4-2W for qemu-devel@nongnu.org; Tue, 09 Jul 2019 01:50:47 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hkj1a-0007Py-1E for qemu-devel@nongnu.org; Tue, 09 Jul 2019 01:50:47 -0400 Received: from mx1.redhat.com ([209.132.183.28]:57120) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hkj1Z-0007Pc-SA for qemu-devel@nongnu.org; Tue, 09 Jul 2019 01:50:45 -0400 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id C71013099FC5; Tue, 9 Jul 2019 05:42:07 +0000 (UTC) Received: from blackfin.pond.sub.org (ovpn-116-111.ams2.redhat.com [10.36.116.111]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 8EFFD5C2F1; Tue, 9 Jul 2019 05:42:07 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 3F10A1138648; Tue, 9 Jul 2019 07:42:01 +0200 (CEST) From: Markus Armbruster To: Peter Maydell References: <1534182832-554-1-git-send-email-aleksandar.markovic@rt-rk.com> <1534182832-554-5-git-send-email-aleksandar.markovic@rt-rk.com> <4da49ffe-902f-2cf2-8a21-2bbd511b17a4@weilnetz.de> Date: Tue, 09 Jul 2019 07:42:01 +0200 In-Reply-To: (Peter Maydell's message of "Mon, 8 Jul 2019 09:42:31 +0100") Message-ID: <87zhlnahna.fsf@dusky.pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.41]); Tue, 09 Jul 2019 05:42:11 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] Handling of fall through code (was: [PATCH v8 04/87] target/mips: Mark switch fallthroughs with interpretable comments X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Paul Burton , Stefan Markovic , Stefan Weil , Riku Voipio , Richard Henderson , QEMU Developers , Laurent Vivier , Aleksandar Markovic , Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= , Aleksandar Markovic , Petar Jovanovic , Aurelien Jarno Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Peter Maydell writes: > On Sun, 7 Jul 2019 at 21:26, Stefan Weil wrote: >> This is a general problem all over the QEMU code. I usually compile with >> nearly all warnings enabled and get now lots of errors with the latest >> code and after updating to gcc-8.3.0 (Debian buster). It should be >> reproducible by enabling -Werror=implicit-fallthrough. > > Coverity warns about implicit fallthroughs, and we are > currently warning-free in that department, so I think > our remaining problems are largely down to perhaps > using idioms which the compiler doesn't spot. > Being able to enable gcc implicit-fallthrough errors would > definitely be better than spotting them only after the > fact with Coverity. > >> I suggest to enable -Werror=implicit-fallthrough by default and add a >> new macro to mark all fallthrough locations which are correct, but not >> accepted by the compiler. > > I'm not sure why we need a macro. Our standard way to > mark fallthrough is /* fall through */, which has hundreds > of uses in the codebase. -Wimplicit-fallthrough=2 will match this, > so it seems simpler to just use that rather than to rework > how we mark fallthroughs. > > Since vixl is 3rd-party code it might be easier to just > add -Wno-implicit-fallthrough to the cflags that > disas/libvixl/Makefile.objs sets up for building those files. > (We should check also for newer libvixl and/or suggest > something upstream that works with gcc.) Concur.