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bh=S4/NL/KGQKBSMdAEfz8eWXb9JiEt3fUU7n7P1UHlDIs=; b=AzejQ37nZf4YszF79ZkCaCVsvO7eeWmYUCAMEEW9vbjCZRWPfruPMmItWfwu6XMQVS8SW/ 4HJsGiN7bZDSCkU2juotRO6bMFJSPHrvzbTbKotKJHFmoAyE+izOaIPmN56R0UXb19VO2R HZDrAKjmu5Ciglb/EJzcoabCKJ+7NYk= 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-435-73iB2FqzN3qZiYR340bA2Q-1; Tue, 27 Oct 2020 07:26:25 -0400 X-MC-Unique: 73iB2FqzN3qZiYR340bA2Q-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 285D28DB60A; Tue, 27 Oct 2020 11:26:24 +0000 (UTC) Received: from thuth.remote.csb (ovpn-115-35.ams2.redhat.com [10.36.115.35]) by smtp.corp.redhat.com (Postfix) with ESMTP id 6975055772; Tue, 27 Oct 2020 11:26:22 +0000 (UTC) Subject: Re: [PATCH v2 2/6] configure: avoid new clang 11+ warnings To: Paolo Bonzini , Daniele Buono , Cornelia Huck , qemu-devel@nongnu.org References: <20201023200645.1055-1-dbuono@linux.vnet.ibm.com> <20201023200645.1055-3-dbuono@linux.vnet.ibm.com> <96d4c76c-dfbb-f985-2718-0892ea1b83d4@redhat.com> <98a03470-4694-f63a-7104-ae576e4799ce@redhat.com> From: Thomas Huth Message-ID: <4ca1ef0b-fe52-a5e5-485a-2827fda58f4d@redhat.com> Date: Tue, 27 Oct 2020 12:26:21 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: <98a03470-4694-f63a-7104-ae576e4799ce@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=thuth@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=216.205.24.124; envelope-from=thuth@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/10/27 01:06:06 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -42 X-Spam_score: -4.3 X-Spam_bar: ---- X-Spam_report: (-4.3 / 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, NICE_REPLY_A=-2.167, 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=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: Alexander Bulekov , =?UTF-8?Q?Daniel_P_=2e_Berrang=c3=a9?= , Janosch Frank Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 26/10/2020 16.12, Paolo Bonzini wrote: > On 26/10/20 16:03, Daniele Buono wrote: >> Hi Paolo, >> I reorganized UASStatus to put uas_iu at the end and it works fine. >> Unfortunately, this uncovered another part of the code with a similar >> issue (variable sized type not at the end of the struct), here: >> >> In file included from ../qemu-cfi-v3/target/s390x/diag.c:21: >> ../qemu-cfi-v3/hw/s390x/ipl.h:161:23: error: field 'iplb' with variable >> sized type 'IplParameterBlock' (aka 'union IplParameterBlock') not at >> the end of a struct or class is a GNU extension >> [-Werror,-Wgnu-variable-sized-type-not-at-end] >>     IplParameterBlock iplb; >>                       ^ >> ../qemu-cfi-v3/hw/s390x/ipl.h:162:23: error: field 'iplb_pv' with >> variable sized type 'IplParameterBlock' (aka 'union IplParameterBlock') >> not at the end of a struct or class is a GNU extension >> [-Werror,-Wgnu-variable-sized-type-not-at-end] >>     IplParameterBlock iplb_pv; >> >> My understanding is that each of these IplParameterBlock may contain >> either a IPLBlockPV or a IplBlockFcp, which both end with a variable >> sized field (an array). >> >> Adding maintainers of s390x to see if they have a suggested solution to >> avoid disabling the warning. > > This one seems okay because the union constrains the size to 4K. If > "[0]" is enough to shut up the compiler, I'd say do that. The "IplBlockFcp fcp" part seems to be completely unused, so I think you could even remove that IplBlockFcp struct. For IPLBlockPV I agree with Paolo, it's likely easiest to use [0] for that struct. Thomas