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[209.51.188.17]) by mx.google.com with ESMTPS id t3-20020a05622a180300b00419393d311dsi1132548qtc.218.2023.10.13.05.42.54 for (version=TLS1_2 cipher=ECDHE-ECDSA-CHACHA20-POLY1305 bits=256/256); Fri, 13 Oct 2023 05:42:55 -0700 (PDT) Received-SPF: pass (google.com: domain of qemu-arm-bounces+alex.bennee=linaro.org@nongnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; Authentication-Results: mx.google.com; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b=VqE8dypI; spf=pass (google.com: domain of qemu-arm-bounces+alex.bennee=linaro.org@nongnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom="qemu-arm-bounces+alex.bennee=linaro.org@nongnu.org"; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qrHUa-0006UF-M8; Fri, 13 Oct 2023 08:42:12 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qrHUZ-0006Tm-Cf for qemu-arm@nongnu.org; Fri, 13 Oct 2023 08:42:11 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qrHUX-0007HU-Ql for qemu-arm@nongnu.org; Fri, 13 Oct 2023 08:42:11 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1697200929; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=mYGKlFKk2qCdI5bNLR4/PeedFlKJXNpjGwbRxMhZf5c=; b=VqE8dypIwsgGcZ3uc6n2DEAtyMVpWaH2YxPG05Dyuyyi/3wtcJz8mYzY2qMloXJqYXsZBH EWfIG+h/H5LpdoYNaaqmJzqw3sKKK4Y5fmKe8OUzE3JP6CEas/wIo8hmizgUfx0DVM2Y33 PTTJA3hWOhvJ1KCPttMga32thsiuHxk= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-347--_VMAzSePjmVqTZRX_4oFg-1; Fri, 13 Oct 2023 08:41:55 -0400 X-MC-Unique: -_VMAzSePjmVqTZRX_4oFg-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 829F1185A79C; Fri, 13 Oct 2023 12:41:55 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.39.193.72]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 607C71C060DF; Fri, 13 Oct 2023 12:41:55 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 7068F21E6A21; Fri, 13 Oct 2023 14:41:54 +0200 (CEST) From: Markus Armbruster To: Emmanouil Pitsidianakis Cc: qemu-devel@nongnu.org, qemu-arm@nongnu.org, qemu-block@nongnu.org Subject: Re: [RFC PATCH 00/78] Strict disable implicit fallthrough References: Date: Fri, 13 Oct 2023 14:41:54 +0200 In-Reply-To: (Emmanouil Pitsidianakis's message of "Fri, 13 Oct 2023 10:47:04 +0300") Message-ID: <87o7h2hey5.fsf@pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.7 Received-SPF: pass client-ip=170.10.129.124; envelope-from=armbru@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-arm@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-arm-bounces+alex.bennee=linaro.org@nongnu.org Sender: qemu-arm-bounces+alex.bennee=linaro.org@nongnu.org X-TUID: 8uGJOJKsBtUt Emmanouil Pitsidianakis writes: > Hello, > > This RFC is inspired by the kernel's move to -Wimplicit-fallthrough=3 > back in 2019.[0] > We take one step (or two) further by increasing it to 5 which rejects > fall through comments and requires an attribute statement. > > [0]: > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=a035d552a93b > > The line differences are not many, but they spread all over different > subsystems, architectures and devices. An attempt has been made to split > them in cohesive patches to aid post-RFC review. Part of the RFC is to > determine whether these patch divisions needs improvement. > > Main questions this RFC poses > ============================= > > - Is this change desirable and net-positive. Unwanted fallthrough is an easy mistake to make, and -Wimplicit-fallthrough=N helps avoid it. The question is how far up we need to push N. Right now we're at N=2. Has unwanted fallthrough been a problem? > - Should the `fallthrough;` pseudo-keyword be defined like in the Linux > kernel, or use glib's G_GNUC_FALLTHROUGH, or keep the already existing > QEMU_FALLTHROUGH macro. > - Should fallthrough comments be removed if they do not include extra > information. Valid questions, but they don't need answers until after picking our N. [...]