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=-5.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,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 9DA3CC64E8A for ; Tue, 1 Dec 2020 07:39:34 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (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 0F9132085B for ; Tue, 1 Dec 2020 07:39:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="kENb9Cma" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0F9132085B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=telegraphics.com.au Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-i3c-bounces+linux-i3c=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version:References:Message-ID:In-Reply-To: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=b/yDsuHUuqnF7XOXT6eAMn+mhUeeyzJ0F9wJUOLZX1o=; b=kENb9Cmack88b++fd8u+4FNFW JWfs0f0sJ3u59AZ6i3AtsoarV7vRPz/VQZduwU0cfm4zbniNngGex7mNilySkaIdZMU8nOMg2/Ijx 95MeiXoXp+M3F8Vu2TsyWQPrfKzyjcyQNvkbbbNyC5w0cFOfNI3GvcKHTWams8TbjRhwuZJNQB0R+ bLcoG0ciEXrNi/0kbiXQPsF99l5ui4WPc/ictqYI/kZ/w7h7m7LwzgPCe3xkLXn6Oxt0snJZm3/4N vy82TfJJ3GWahVOsf5uBjnL4g4LPkFK7LLi/Jlkn99BM+4uqAJleYhBJuBFC4c5QYB8Zl9I4sD0ld Ae1buuOEQ==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kk0G4-0007UF-VN; Tue, 01 Dec 2020 07:39:33 +0000 Received: from kvm5.telegraphics.com.au ([98.124.60.144]) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1ki46q-0000gF-R0; Wed, 25 Nov 2020 23:22:01 +0000 Received: from localhost (localhost.localdomain [127.0.0.1]) by kvm5.telegraphics.com.au (Postfix) with ESMTP id 414EA2A490; Wed, 25 Nov 2020 18:21:54 -0500 (EST) Date: Thu, 26 Nov 2020 10:21:54 +1100 (AEDT) From: Finn Thain To: Nick Desaulniers Subject: Re: [Intel-wired-lan] [PATCH 000/141] Fix fall-through warnings for Clang In-Reply-To: Message-ID: References: <202011201129.B13FDB3C@keescook> <20201120115142.292999b2@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> <202011220816.8B6591A@keescook> <9b57fd4914b46f38d54087d75e072d6e947cb56d.camel@HansenPartnership.com> <0147972a72bc13f3629de8a32dee6f1f308994b5.camel@HansenPartnership.com> <20201123130348.GA3119@embeddedor> <8f5611bb015e044fa1c0a48147293923c2d904e4.camel@HansenPartnership.com> <202011241327.BB28F12F6@keescook> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201125_182200_905723_F9019AB4 X-CRM114-Status: GOOD ( 13.21 ) X-Mailman-Approved-At: Tue, 01 Dec 2020 02:39:24 -0500 X-BeenThere: linux-i3c@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: alsa-devel@alsa-project.org, bridge@lists.linux-foundation.org, target-devel@vger.kernel.org, Greg KH , linux-iio@vger.kernel.org, linux-wireless , Jonathan Cameron , linux-fbdev@vger.kernel.org, dri-devel , "Gustavo A. R. Silva" , James Bottomley , linux-ide@vger.kernel.org, dm-devel@redhat.com, keyrings@vger.kernel.org, linux-mtd@lists.infradead.org, GR-everest-linux-l2@marvell.com, wcn36xx@lists.infradead.org, linux-i3c@lists.infradead.org, linux1394-devel@lists.sourceforge.net, linux-afs@lists.infradead.org, drbd-dev@lists.linbit.com, devel@driverdev.osuosl.org, linux-cifs@vger.kernel.org, rds-devel@oss.oracle.com, linux-scsi@vger.kernel.org, linux-acpi@vger.kernel.org, linux-rdma@vger.kernel.org, oss-drivers@netronome.com, linux-atm-general@lists.sourceforge.net, ceph-devel@vger.kernel.org, amd-gfx list , linux-stm32@st-md-mailman.stormreply.com, cluster-devel@redhat.com, usb-storage@lists.one-eyed-alien.net, linux-mmc@vger.kernel.org, coreteam@netfilter.org, intel-wired-lan@lists.osuosl.org, linux-input@vger.kernel.org, Miguel Ojeda , Jakub Kicinski , linux-ext4@vger.kernel.org, virtualization@lists.linux-foundation.org, netfilter-devel@vger.kernel.org, linux-media@vger.kernel.org, Kees Cook , selinux@vger.kernel.org, linux-arm-msm , intel-gfx@lists.freedesktop.org, linux-sctp@vger.kernel.org, reiserfs-devel@vger.kernel.org, linux-geode@lists.infradead.org, linux-block@vger.kernel.org, linux-gpio@vger.kernel.org, op-tee@lists.trustedfirmware.org, linux-mediatek@lists.infradead.org, xen-devel@lists.xenproject.org, nouveau@lists.freedesktop.org, linux-hams@vger.kernel.org, Nathan Chancellor , linux-can@vger.kernel.org, Linux ARM , linux-hwmon@vger.kernel.org, "maintainer:X86 ARCHITECTURE \(32-BIT AND 64-BIT\)" , linux-watchdog@vger.kernel.org, GR-Linux-NIC-Dev@marvell.com, Linux Memory Management List , Network Development , linux-decnet-user@lists.sourceforge.net, samba-technical@lists.samba.org, LKML , Linux-Renesas , linux-security-module@vger.kernel.org, linux-usb@vger.kernel.org, tipc-discussion@lists.sourceforge.net, "open list:HARDWARE RANDOM NUMBER GENERATOR CORE" , patches@opensource.cirrus.com, Joe Perches , linux-integrity@vger.kernel.org, linux-nfs@vger.kernel.org, linux-hardening@vger.kernel.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-i3c" Errors-To: linux-i3c-bounces+linux-i3c=archiver.kernel.org@lists.infradead.org On Wed, 25 Nov 2020, Nick Desaulniers wrote: > On Wed, Nov 25, 2020 at 1:33 PM Finn Thain > wrote: > > > > Or do you think that a codebase can somehow satisfy multiple checkers > > and their divergent interpretations of the language spec? > > Have we found any cases yet that are divergent? I don't think so. There are many implementations, so I think you are guaranteed to find more divergence if you look. That's because the spec is full of language like this: "implementations are encouraged not to emit a diagnostic" and "implementations are encouraged to issue a diagnostic". Some implementations will decide to not emit (under the premise that vast amounts of existing code would have to get patched until the compiler goes quiet) whereas other implementations will decide to emit (under the premise that the author is doing the checking and not the janitor or the packager). > It sounds to me like GCC's cases it warns for is a subset of Clang's. > Having additional coverage with Clang then should ensure coverage for > both. > If that claim were true, the solution would be simple. (It's not.) For the benefit of projects that enable -Werror and projects that nominated gcc as their preferred compiler, clang would simply need a flag to enable conformance with gcc by suppressing those additional warnings that clang would normally produce. This simple solution is, of course, completely unworkable, since it would force clang to copy some portion of gcc's logic (rewritten under LLVM's unique license) and then to track future changes to that portion of gcc indefinitely. -- linux-i3c mailing list linux-i3c@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-i3c