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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 4C38EE81E03 for ; Fri, 6 Oct 2023 14:46:24 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qom50-0006nE-28; Fri, 06 Oct 2023 10:45:26 -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 1qom4x-0006n2-NL for qemu-devel@nongnu.org; Fri, 06 Oct 2023 10:45:23 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qom4v-00077S-2S for qemu-devel@nongnu.org; Fri, 06 Oct 2023 10:45:22 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1696603519; 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: content-transfer-encoding:content-transfer-encoding; bh=0msHmLMhDB9eOh7d8vMJI2gMMzuw3Fsi3idR3jjf9kQ=; b=HtUntz4taH3h4A8FllTdBmw/UMH2IcFon6Uxs0Mh8+HMaBZcCFoBnksnZCStskliDxcexg E3tWcI9rRwHz9tlqNLQgJ4a1CE3NQSPBsB3ZubzWV8DVOA1RLxrQFkqKQMi6bZOHhk+W5S pZlz7Gj48lML95GNscGtoW7oCCeEAtM= 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-106-8MfIRgZ9N8On55_uul-HPg-1; Fri, 06 Oct 2023 10:45:17 -0400 X-MC-Unique: 8MfIRgZ9N8On55_uul-HPg-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (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 6173985A5BE for ; Fri, 6 Oct 2023 14:45:17 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.39.192.25]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 4091310EE859 for ; Fri, 6 Oct 2023 14:45:17 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 3499B21E6904; Fri, 6 Oct 2023 16:45:16 +0200 (CEST) From: Markus Armbruster To: qemu-devel@nongnu.org Cc: Gerd Hoffmann , =?utf-8?Q?Marc-Andr=C3=A9_Lureau?= Subject: [v3] Help wanted for enabling -Wshadow=local Date: Fri, 06 Oct 2023 16:45:16 +0200 Message-ID: <87mswvg683.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; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.1 on 10.11.54.3 Received-SPF: pass client-ip=170.10.133.124; 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_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: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Local variables shadowing other local variables or parameters make the code needlessly hard to understand. Bugs love to hide in such code. Evidence: "[PATCH v3 1/7] migration/rdma: Fix save_page method to fail on polling error". Enabling -Wshadow would prevent bugs like this one. But we have to clean up all the offenders first. Quite a few people responded to my calls for help. Thank you so much! I'm collecting patches in my git repo at https://repo.or.cz/qemu/armbru.git in branch shadow-next. All but the last two are in a pending pull request. My test build is down to seven files with warnings. "[PATCH v2 0/3] hexagon: GETPC() and shadowing fixes" takes care of four, but it needs a rebase. Remaining three: In file included from ../hw/display/virtio-gpu-virgl.c:19: ../hw/display/virtio-gpu-virgl.c: In function =E2=80=98virgl_cmd_submit= _3d=E2=80=99: /work/armbru/qemu/include/hw/virtio/virtio-gpu.h:228:16: warning: decla= ration of =E2=80=98s=E2=80=99 shadows a previous local [-Wshadow=3Dcompatib= le-local] 228 | size_t s; = \ | ^ ../hw/display/virtio-gpu-virgl.c:215:5: note: in expansion of macro =E2= =80=98VIRTIO_GPU_FILL_CMD=E2=80=99 215 | VIRTIO_GPU_FILL_CMD(cs); | ^~~~~~~~~~~~~~~~~~~ ../hw/display/virtio-gpu-virgl.c:213:12: note: shadowed declaration is = here 213 | size_t s; | ^ In file included from ../contrib/vhost-user-gpu/virgl.h:18, from ../contrib/vhost-user-gpu/virgl.c:17: ../contrib/vhost-user-gpu/virgl.c: In function =E2=80=98virgl_cmd_submi= t_3d=E2=80=99: ../contrib/vhost-user-gpu/vugpu.h:167:16: warning: declaration of =E2= =80=98s=E2=80=99 shadows a previous local [-Wshadow=3Dcompatible-local] 167 | size_t s; = \ | ^ ../contrib/vhost-user-gpu/virgl.c:203:5: note: in expansion of macro = =E2=80=98VUGPU_FILL_CMD=E2=80=99 203 | VUGPU_FILL_CMD(cs); | ^~~~~~~~~~~~~~ ../contrib/vhost-user-gpu/virgl.c:201:12: note: shadowed declaration is= here 201 | size_t s; | ^ ../contrib/vhost-user-gpu/vhost-user-gpu.c: In function =E2=80=98vg_res= ource_flush=E2=80=99: ../contrib/vhost-user-gpu/vhost-user-gpu.c:837:29: warning: declaration= of =E2=80=98i=E2=80=99 shadows a previous local [-Wshadow=3Dlocal] 837 | pixman_image_t *i =3D | ^ ../contrib/vhost-user-gpu/vhost-user-gpu.c:757:9: note: shadowed declar= ation is here 757 | int i; | ^ Gerd, Marc-Andr=C3=A9, or anybody else? More warnings may lurk in code my test build doesn't compile. Need a full CI build with -Wshadow=3Dlocal to find them. Anybody care to kick one off?