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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 31C6EC433B4 for ; Tue, 20 Apr 2021 13:03:50 +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 A1F1A60233 for ; Tue, 20 Apr 2021 13:03:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A1F1A60233 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:56860 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lYq2e-0004DZ-Cb for qemu-devel@archiver.kernel.org; Tue, 20 Apr 2021 09:03:48 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:47826) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lYpze-0002yg-GP; Tue, 20 Apr 2021 09:00:42 -0400 Received: from mx2.suse.de ([195.135.220.15]:47156) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lYpzZ-0003fJ-1x; Tue, 20 Apr 2021 09:00:42 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id A8A0BB2E6; Tue, 20 Apr 2021 13:00:34 +0000 (UTC) Subject: Re: [RFC v2 04/13] target/s390x: remove tcg-stub.c To: David Hildenbrand , Cornelia Huck , Thomas Huth , Richard Henderson References: <20210420103616.32731-1-cfontana@suse.de> <20210420103616.32731-5-cfontana@suse.de> From: Claudio Fontana Message-ID: <3f7d3cda-9319-9004-7568-55459bc05c78@suse.de> Date: Tue, 20 Apr 2021 15:00:33 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.12.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=195.135.220.15; envelope-from=cfontana@suse.de; helo=mx2.suse.de X-Spam_score_int: -41 X-Spam_score: -4.2 X-Spam_bar: ---- X-Spam_report: (-4.2 / 5.0 requ) BAYES_00=-1.9, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action 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: Halil Pasic , Christian Borntraeger , qemu-s390x@nongnu.org, qemu-devel@nongnu.org, Paolo Bonzini Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 4/20/21 2:54 PM, David Hildenbrand wrote: > On 20.04.21 12:36, Claudio Fontana wrote: >> now that we protect all calls to the tcg-specific functions >> with if (tcg_enabled()), we do not need the TCG stub anymore. > > You need compile-time checks, not runtime checks. Any calls have to be > protected by #ifdef, otherwise the compiler might bail out. This is not true though, tcg_enabled() is #defined as 0 if tcg is not enabled. #define kvm_enabled() (0) Compiler will elide the code if after the preprocessor pass the code is: if (0) { } It adds the benefit of actually checking the syntax of the code inside. As long as the prototypes are in sight, we rely on this for i386 and ARM already, to avoid accumulating stubs. > > Maybe you just wanted to state it differently in this patch description. > Thanks, Claudio