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=-12.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham 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 F1199C433E0 for ; Mon, 8 Mar 2021 13:59:57 +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 67BE7651D3 for ; Mon, 8 Mar 2021 13:59:57 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 67BE7651D3 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]:38364 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lJGQO-0001gj-7y for qemu-devel@archiver.kernel.org; Mon, 08 Mar 2021 08:59:56 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:54578) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lJGMh-00052Q-Ke for qemu-devel@nongnu.org; Mon, 08 Mar 2021 08:56:07 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:39011) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1lJGMb-0003DY-7m for qemu-devel@nongnu.org; Mon, 08 Mar 2021 08:56:07 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1615211759; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=nhXao7s4LzPsFulZf4A/rFJAKES8LEFUec05327le1s=; b=ImyAOF9yfxBKoegnaHxNDJS8Vir6xJyGMcG9/fUY75R0jcofWXgyKccPFZwL1nOswjFCoI +8sUaJqoNmX79/rEXDiaTghmGQqEDfHXLjHUAWU015K6FIlYFjrBJFIojn6/D9+XgeAXEq 04HFZwOr+OcosqTvi0pk3GNe4Sdjj8Y= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-559-oPT-mIt9P5yqOrgBqSDK8g-1; Mon, 08 Mar 2021 08:55:57 -0500 X-MC-Unique: oPT-mIt9P5yqOrgBqSDK8g-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 0A97D1932480; Mon, 8 Mar 2021 13:55:56 +0000 (UTC) Received: from redhat.com (ovpn-114-69.ams2.redhat.com [10.36.114.69]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 1873C5D6D5; Mon, 8 Mar 2021 13:55:54 +0000 (UTC) Date: Mon, 8 Mar 2021 13:55:52 +0000 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Christian Ehrhardt Subject: Re: [PATCH] disas: Fix build with glib2.0 >=2.67.3 Message-ID: References: <20210223145646.4129643-1-christian.ehrhardt@canonical.com> MIME-Version: 1.0 In-Reply-To: User-Agent: Mutt/2.0.5 (2021-01-21) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=berrange@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=216.205.24.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -29 X-Spam_score: -3.0 X-Spam_bar: --- X-Spam_report: (-3.0 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.251, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, 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: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Cc: Peter Maydell , qemu-devel Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Mon, Mar 08, 2021 at 02:50:39PM +0100, Christian Ehrhardt wrote: > On Wed, Feb 24, 2021 at 2:15 PM Daniel P. Berrangé wrote: > > > > On Wed, Feb 24, 2021 at 01:07:33PM +0000, Peter Maydell wrote: > > > On Wed, 24 Feb 2021 at 11:04, Daniel P. Berrangé wrote: > > > > So from osdep.h I think something like this is likely sufficient: > > > > > > > > diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h > > > > index ba15be9c56..7a1d83a8b6 100644 > > > > --- a/include/qemu/osdep.h > > > > +++ b/include/qemu/osdep.h > > > > @@ -126,6 +126,7 @@ extern int daemon(int, int); > > > > #include "glib-compat.h" > > > > #include "qemu/typedefs.h" > > > > > > > > +extern "C" { > > > > > > Needs to be protected by #ifdef so it's only relevant for the > > > C++ compiler, right? > > > > > > > /* > > > > * For mingw, as of v6.0.0, the function implementing the assert macro is > > > > * not marked as noreturn, so the compiler cannot delete code following an > > > > @@ -722,4 +723,6 @@ static inline int platform_does_not_support_system(const char *command) > > > > } > > > > #endif /* !HAVE_SYSTEM_FUNCTION */ > > > > > > > > +} > > > > + > > > > #endif > > > > > > > > > > > > We'll also need to them protect any local headers we use before this point. > > > > > > > > $ grep #include ../../../include/qemu/osdep.h | grep -v '<' > > > > #include "config-host.h" > > > > #include CONFIG_TARGET > > > > #include "exec/poison.h" > > > > #include "qemu/compiler.h" > > > > #include "sysemu/os-win32.h" > > > > #include "sysemu/os-posix.h" > > > > #include "glib-compat.h" > > > > #include "qemu/typedefs.h" > > > > > > > > and transitively through that list, but I think there's no too many > > > > more there. > > > > > > Is there anything we can do to make the compiler complain if we > > > get this wrong? Otherwise it seems likely that we'll end up > > > accidentally putting things inside or outside 'extern "C"' > > > declarations when they shouldn't be, as we make future changes > > > to our headers. > > > > There's nothing easy I know of to highlight this. It is more the kind > > of thing checkpatch would have to look at - complain if there is > > anything which isn't a preprocessor include directive or comment > > before the 'extern'. > > > > > (The other approach would be to try to get rid of the > > > C++ in the codebase. We could probably say 'drop vixl > > > and always use capstone', for instance.) > > > > Yeah, getting rid of C++ would probably be the sanest solution long > > term. > > Just as an input on short-term alternatives, > in open-vm-tools we've found to follow > https://developer.gnome.org/glib/stable/glib-Version-Information.html#GLIB-VERSION-MIN-REQUIRED:CAPS > to be an easy fix for the time being. > Which in the autoconf magic there was just: > +AC_DEFINE(GLIB_VERSION_MIN_REQUIRED, GLIB_VERSION_2_34, [Ignore > post 2.34 deprecations]) > +AC_DEFINE(GLIB_VERSION_MAX_ALLOWED, GLIB_VERSION_2_34, [Prevent > post 2.34 APIs]) > (Or any other/newer version that one would want to select) > > Not sure what would apply to qemu here, but I wanted to let you know > of the overall concept in regard to this issue. QEMU already uses these macros but they can't protect against all scenarios. Principally they avoid you accidentally using a newly introduced public API. The scenario in this thread doesn't involve a new API, so those macros don't help here, you need to actually compile against the new version to see the problem Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|