From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by sourceware.org (Postfix) with ESMTPS id 035183858D35 for ; Wed, 15 Feb 2023 09:50:15 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 035183858D35 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1676454614; 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:in-reply-to:in-reply-to: references:references; bh=2EHyvLcYODO2C/W3U5+O/scjOv4fQnFmAK3x4G9eqyM=; b=Xyd5niHpDtV+XUeGxR5hT+gsRrsLkvpY8QmrYxAwADX1fdqgXkKDUfNGZw7/sP5uqjZw/g DLfGZZ0JbtfXKrWhYkasCLvU5RmKBT4IXjf+epgazl0zLhQPy/TR5TPqcC3n1C2CWWGEex dmR+R0LZ7jUUTUMWi9na1EhicQVCiOE= 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-635-sSZOpbtwM-6I-zD-dYlIMQ-1; Wed, 15 Feb 2023 04:50:13 -0500 X-MC-Unique: sSZOpbtwM-6I-zD-dYlIMQ-1 Received: from smtp.corp.redhat.com (int-mx10.intmail.prod.int.rdu2.redhat.com [10.11.54.10]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id F3360185A7A4 for ; Wed, 15 Feb 2023 09:50:12 +0000 (UTC) Received: from tucnak.zalov.cz (unknown [10.39.193.203]) by smtp.corp.redhat.com (Postfix) with ESMTPS id DCE46492B15; Wed, 15 Feb 2023 09:50:11 +0000 (UTC) Received: from tucnak.zalov.cz (localhost [127.0.0.1]) by tucnak.zalov.cz (8.17.1/8.17.1) with ESMTPS id 31F9o9jR755515 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT); Wed, 15 Feb 2023 10:50:09 +0100 Received: (from jakub@localhost) by tucnak.zalov.cz (8.17.1/8.17.1/Submit) id 31F9o8ZZ755514; Wed, 15 Feb 2023 10:50:08 +0100 Date: Wed, 15 Feb 2023 10:50:08 +0100 From: Jakub Jelinek To: Marek Polacek Cc: GCC Patches Subject: Re: [PATCH] warn-access: wrong -Wdangling-pointer with labels [PR106080] Message-ID: Reply-To: Jakub Jelinek References: <20230215034815.1276847-1-polacek@redhat.com> MIME-Version: 1.0 In-Reply-To: <20230215034815.1276847-1-polacek@redhat.com> X-Scanned-By: MIMEDefang 3.1 on 10.11.54.10 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Spam-Status: No, score=-3.5 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H2,SPF_HELO_NONE,SPF_NONE,TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: On Tue, Feb 14, 2023 at 10:48:15PM -0500, Marek Polacek via Gcc-patches wrote: > -Wdangling-pointer warns when the address of a label escapes. This > causes grief in OCaml () as > well as in the kernel: > because it uses > > #define _THIS_IP_ ({ __label__ __here; __here: (unsigned long)&&__here; }) > > to get the PC. -Wdangling-pointer is documented to warn about pointers > to objects. However, it uses is_auto_decl which checks DECL_P, but DECL_P > is also true for a label/enumerator/function declaration, none of which is > an object. Rather, it should use auto_var_p which correctly checks VAR_P > and PARM_DECL. and RESULT_DECL ;) > Bootstrapped/regtested on ppc64le-pc-linux-gnu, ok for trunk and 12? > > PR middle-end/106080 > > gcc/ChangeLog: > > * gimple-ssa-warn-access.cc (is_auto_decl): Remove. Use auto_var_p > instead. > > gcc/testsuite/ChangeLog: > > * c-c++-common/Wdangling-pointer-10.c: New test. > * c-c++-common/Wdangling-pointer-9.c: New test. > --- /dev/null > +++ b/gcc/testsuite/c-c++-common/Wdangling-pointer-9.c > @@ -0,0 +1,9 @@ > +/* PR middle-end/106080 */ > +/* { dg-do compile } */ > +/* { dg-options "-O2 -Wdangling-pointer" } */ > + > +void > +foo (void **failaddr) > +{ > + *failaddr = ({ __label__ __here; __here: &&__here; }); > +} Perhaps add dg-bogus above just to make it more clear what we are testing in the test? Otherwise LGTM. Jakub