From patchwork Thu May 25 21:20:46 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jason Merrill X-Patchwork-Id: 767147 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from sourceware.org (server1.sourceware.org [209.132.180.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3wYhym3JpMz9rxw for ; Fri, 26 May 2017 07:21:18 +1000 (AEST) Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=gcc.gnu.org header.i=@gcc.gnu.org header.b="Cbhwjuil"; dkim-atps=neutral DomainKey-Signature: a=rsa-sha1; c=nofws; d=gcc.gnu.org; h=list-id :list-unsubscribe:list-archive:list-post:list-help:sender :mime-version:in-reply-to:references:from:date:message-id :subject:to:cc:content-type; q=dns; s=default; b=K9D42qYwMSpR2N5 KtVrdXtkVh1bzjxIIQ8jnl7+Bh8fusEhOb3TuljThGtsMuz60rf8S8ZltKaW4U8P oFYB5sW+hdfRolQVb8Q0wxbgSYxk3pn0F01rOBo72pezcE0oBdUIq6BOox9zBK1p tExEXns/oC25dNCVMDH4LG95rQD0= DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=gcc.gnu.org; h=list-id :list-unsubscribe:list-archive:list-post:list-help:sender :mime-version:in-reply-to:references:from:date:message-id :subject:to:cc:content-type; s=default; bh=T4OYRcC27VHaXYYaQI9RN wJvIIE=; b=CbhwjuilL8ZrrZ1FDolwXw9oJBXIHWK8IY+swak8NiXLQXtI9oZXC RQdq4CNKuqgxxzQu1PYSy935V1GSvHnzyODuDKcY1VyPlpIKxHxei92CXsMsXX8b 5+J4k0B9YJrz3BtC/1TTQna2/I8DdPRIL1MHOLouyZzC+jnujz5QCQ= Received: (qmail 42866 invoked by alias); 25 May 2017 21:21:07 -0000 Mailing-List: contact gcc-patches-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Archive: List-Post: List-Help: Sender: gcc-patches-owner@gcc.gnu.org Delivered-To: mailing list gcc-patches@gcc.gnu.org Received: (qmail 42845 invoked by uid 89); 25 May 2017 21:21:07 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-24.9 required=5.0 tests=AWL, BAYES_00, GIT_PATCH_0, GIT_PATCH_1, GIT_PATCH_2, GIT_PATCH_3, RCVD_IN_DNSWL_NONE, RCVD_IN_SORBS_SPAM autolearn=ham version=3.3.2 spammy= X-HELO: mail-io0-f181.google.com Received: from mail-io0-f181.google.com (HELO mail-io0-f181.google.com) (209.85.223.181) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Thu, 25 May 2017 21:21:05 +0000 Received: by mail-io0-f181.google.com with SMTP id k91so144545793ioi.1 for ; Thu, 25 May 2017 14:21:08 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=uqqwfx3XjDjMG46DRk2+xZQjwD6W/sXZ7nrAiiqqJlg=; b=BAt+c9hPHRNXTMCkDUEV9KJfcytm72eR7YQVHfBl6WU9SWwPLuQRDkZPtXTVMd5YZj wFScRUpnCZPnRikPvMC1+4cCUz69BGqbED5KwDI3mZEdLpJPp1EaAp2y1o5bm4H7FaQY F4PWpPRG85pljk1qGpyZjvQiPhpVkWHgmYOpuDXmgTt7J9wOOyD0thr7XTAeW617VQ6X 3ImpQe8u1hkZJGj88ficq3qnihg9ui3pw2+rjLYqflX6/BcnbxHsZ18NZquo6bwyO0hv igfYJkNH39TVqKNuLww+4JuwSjYx1qoQXk8AjVlvwJG+cWwSxahjcATla/v3CZFHMklr dhqw== X-Gm-Message-State: AODbwcCneSMNSIb9LFjho9kWFMB1nOVBmk5jAU74GWCz6m+wj72mqWhQ noRoYmvWHmLU6A7dTB+GxMbi9U8WNGCG X-Received: by 10.107.40.8 with SMTP id o8mr27652531ioo.192.1495747267478; Thu, 25 May 2017 14:21:07 -0700 (PDT) MIME-Version: 1.0 Received: by 10.107.6.226 with HTTP; Thu, 25 May 2017 14:20:46 -0700 (PDT) In-Reply-To: <20170525090813.GZ8499@tucnak> References: <20170525085156.GY8499@tucnak> <20170525090813.GZ8499@tucnak> From: Jason Merrill Date: Thu, 25 May 2017 17:20:46 -0400 Message-ID: Subject: Re: C++ PATCH for testsuite failures with -std=c++17 To: Jakub Jelinek Cc: gcc-patches List X-IsSubscribed: yes On Thu, May 25, 2017 at 5:08 AM, Jakub Jelinek wrote: > On Thu, May 25, 2017 at 10:51:56AM +0200, Jakub Jelinek wrote: >> On Tue, May 09, 2017 at 04:37:16PM -0400, Jason Merrill wrote: >> > For C++17 aggregate bases, we have started adding base fields for >> > empty bases. The code for calculating whether a class is standard >> > layout needs to ignore these. >> > >> > The C++17 mode diagnostic for direct-enum-init1.C was incorrect. >> > >> > Tested x86_64-pc-linux-gnu, applying to trunk. >> >> > commit 9a612cc30d4b3ef905ce45304545d8b99a3cf5b9 >> > Author: Jason Merrill >> > Date: Tue May 9 14:15:38 2017 -0400 >> > >> > * class.c (check_bases): Ignore empty bases. >> >> This should have referenced PR c++/80605 (and is also a 7 regression). >> >> > diff --git a/gcc/cp/class.c b/gcc/cp/class.c >> > index fc71766..085dbc3 100644 >> > --- a/gcc/cp/class.c >> > +++ b/gcc/cp/class.c >> > @@ -1860,7 +1860,9 @@ check_bases (tree t, >> > members */ >> > for (basefield = TYPE_FIELDS (basetype); basefield; >> > basefield = DECL_CHAIN (basefield)) >> > - if (TREE_CODE (basefield) == FIELD_DECL) >> > + if (TREE_CODE (basefield) == FIELD_DECL >> > + && DECL_SIZE (basefield) >> > + && !integer_zerop (DECL_SIZE (basefield))) >> >> Is that what we really want? I mean, shouldn't we at least also >> check that the basefield we want to ignore is DECL_ARTIFICIAL, >> or that it doesn't have DECL_NAME or something similar, to avoid >> considering user fields with zero size the same? >> I believe your change changes e.g.: >> struct S { int a[0]; }; >> struct T : public S { int b[0]; int c; }; >> bool q = __is_standard_layout (T); >> which previously e.g. with -std=gnu++14 emitted q = false, but >> now emits q = true. > > We even have DECL_FIELD_IS_BASE macro, so can't the above be > if (TREE_CODE (basefield) == FIELD_DECL > && !DECL_FIELD_IS_BASE (basefield)) > or > if (TREE_CODE (basefield) == FIELD_DECL > && (!DECL_FIELD_IS_BASE (basefield) > || (DECL_SIZE (basefield) > && !integer_zerop (DECL_SIZE (basefield))))) > or something similar? Indeed, thanks. commit 49096cb5bc6c629c619ac9b5e08b971867dd1fc1 Author: Jason Merrill Date: Thu May 25 15:34:13 2017 -0400 PR c++/80605 - __is_standard_layout and zero-length array * class.c (check_bases): Use DECL_FIELD_IS_BASE. diff --git a/gcc/cp/class.c b/gcc/cp/class.c index 984fb09..eddc118 100644 --- a/gcc/cp/class.c +++ b/gcc/cp/class.c @@ -1842,8 +1842,8 @@ check_bases (tree t, for (basefield = TYPE_FIELDS (basetype); basefield; basefield = DECL_CHAIN (basefield)) if (TREE_CODE (basefield) == FIELD_DECL - && DECL_SIZE (basefield) - && !integer_zerop (DECL_SIZE (basefield))) + && !(DECL_FIELD_IS_BASE (basefield) + && integer_zerop (DECL_SIZE (basefield)))) { if (field) CLASSTYPE_NON_STD_LAYOUT (t) = 1; diff --git a/gcc/testsuite/g++.dg/ext/is_std_layout2.C b/gcc/testsuite/g++.dg/ext/is_std_layout2.C new file mode 100644 index 0000000..02dc4f7 --- /dev/null +++ b/gcc/testsuite/g++.dg/ext/is_std_layout2.C @@ -0,0 +1,6 @@ +// { dg-do compile { target c++11 } } +// { dg-options "" } + +struct S { int a[0]; }; +struct T : public S { int b[0]; int c; }; +static_assert(!__is_standard_layout (T), "");