From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Paul Eggert Newsgroups: gmane.emacs.devel Subject: Re: more macOS Clang assume warnings Date: Mon, 24 Aug 2020 17:23:07 -0700 Organization: UCLA Computer Science Department Message-ID: <87c35fba-515b-18ca-598c-72a0baa94113@cs.ucla.edu> References: <5B1F57F1-C671-40D8-8272-2C90E42F2538@acm.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: quoted-printable Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="21979"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 Cc: Bruno Haible , emacs-devel To: =?UTF-8?Q?Mattias_Engdeg=c3=a5rd?= Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Tue Aug 25 02:28:28 2020 Return-path: Envelope-to: ged-emacs-devel@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1kAMp9-0005bY-Hp for ged-emacs-devel@m.gmane-mx.org; Tue, 25 Aug 2020 02:28:27 +0200 Original-Received: from localhost ([::1]:39306 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kAMp8-00059C-JX for ged-emacs-devel@m.gmane-mx.org; Mon, 24 Aug 2020 20:28:26 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:46294) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kAMk7-0006fQ-6U for emacs-devel@gnu.org; Mon, 24 Aug 2020 20:23:15 -0400 Original-Received: from zimbra.cs.ucla.edu ([131.179.128.68]:39520) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kAMk4-0006eM-Ul for emacs-devel@gnu.org; Mon, 24 Aug 2020 20:23:14 -0400 Original-Received: from localhost (localhost [127.0.0.1]) by zimbra.cs.ucla.edu (Postfix) with ESMTP id BDB701600E2; Mon, 24 Aug 2020 17:23:09 -0700 (PDT) Original-Received: from zimbra.cs.ucla.edu ([127.0.0.1]) by localhost (zimbra.cs.ucla.edu [127.0.0.1]) (amavisd-new, port 10032) with ESMTP id Qd8LD6lNFyMc; Mon, 24 Aug 2020 17:23:09 -0700 (PDT) Original-Received: from localhost (localhost [127.0.0.1]) by zimbra.cs.ucla.edu (Postfix) with ESMTP id 0131D1600FD; Mon, 24 Aug 2020 17:23:09 -0700 (PDT) X-Virus-Scanned: amavisd-new at zimbra.cs.ucla.edu Original-Received: from zimbra.cs.ucla.edu ([127.0.0.1]) by localhost (zimbra.cs.ucla.edu [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id cf7HzgZNtj5v; Mon, 24 Aug 2020 17:23:08 -0700 (PDT) Original-Received: from [192.168.1.9] (cpe-75-82-69-226.socal.res.rr.com [75.82.69.226]) by zimbra.cs.ucla.edu (Postfix) with ESMTPSA id A42B61600E2; Mon, 24 Aug 2020 17:23:08 -0700 (PDT) Autocrypt: addr=eggert@cs.ucla.edu; prefer-encrypt=mutual; keydata= LS0tLS1CRUdJTiBQR1AgUFVCTElDIEtFWSBCTE9DSy0tLS0tCgptUUlOQkV5QWNtUUJFQURB QXlIMnhvVHU3cHBHNUQzYThGTVpFb243NGRDdmM0K3ExWEEySjJ0QnkycHdhVHFmCmhweHhk R0E5Smo1MFVKM1BENGJTVUVnTjh0TFowc2FuNDdsNVhUQUZMaTI0NTZjaVNsNW04c0thSGxH ZHQ5WG0KQUF0bVhxZVpWSVlYL1VGUzk2ZkR6ZjR4aEVtbS95N0xiWUVQUWRVZHh1NDd4QTVL aFRZcDVibHRGM1dZRHoxWQpnZDdneDA3QXV3cDdpdzdlTnZub0RUQWxLQWw4S1lEWnpiRE5D UUdFYnBZM2VmWkl2UGRlSStGV1FONFcra2doCnkrUDZhdTZQcklJaFlyYWV1YTdYRGRiMkxT MWVuM1NzbUUzUWpxZlJxSS9BMnVlOEpNd3N2WGUvV0szOEV6czYKeDc0aVRhcUkzQUZINmls QWhEcXBNbmQvbXNTRVNORnQ3NkRpTzFaS1FNcjlhbVZQa25qZlBtSklTcWRoZ0IxRApsRWR3 MzRzUk9mNlY4bVp3MHhmcVQ2UEtFNDZMY0ZlZnpzMGtiZzRHT1JmOHZqRzJTZjF0azVlVThN Qml5Ti9iClowM2JLTmpOWU1wT0REUVF3dVA4NGtZTGtYMndCeHhNQWhCeHdiRFZadWR6eERa SjFDMlZYdWpDT0pWeHEya2wKakJNOUVUWXVVR3FkNzVBVzJMWHJMdzYrTXVJc0hGQVlBZ1Jy NytLY3dEZ0JBZndoU In-Reply-To: <5B1F57F1-C671-40D8-8272-2C90E42F2538@acm.org> Content-Language: en-US Received-SPF: pass client-ip=131.179.128.68; envelope-from=eggert@cs.ucla.edu; helo=zimbra.cs.ucla.edu X-detected-operating-system: by eggs.gnu.org: First seen = 2020/08/24 18:21:40 X-ACL-Warn: Detected OS = Linux 3.1-3.10 X-Spam_score_int: -64 X-Spam_score: -6.5 X-Spam_bar: ------ X-Spam_report: (-6.5 / 5.0 requ) BAYES_00=-1.9, NICE_REPLY_A=-2.25, RCVD_IN_DNSWL_MED=-2.3, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.io gmane.emacs.devel:254210 Archived-At: On 8/24/20 11:54 AM, Mattias Engdeg=C3=A5rd wrote: > The latest assume reformulation caused several warnings like the follow= ing when building with Clang: >=20 > ../../emacs/src/xwidget.h:171:72: warning: control reaches end of non-v= oid > function [-Wreturn-type] > INLINE struct xwidget *lookup_xwidget (Lisp_Object obj) { eassume (0); = } > = ^ > ../../emacs/src/eval.c:1571:1: warning: function declared 'noreturn' sh= ould not > return [-Winvalid-noreturn] > } > ^ >=20 > This is with Apple clang version 11.0.0 (clang-1100.0.33.17) but it loo= ks like the same applies to clang trunk. Thanks for reporting that. I can reproduce the problem with Clang 9.0.1 o= n=20 Fedora 31. For the program at the end of this message, 'clang -O2 -Wall'=20 incorrectly complains "warning: function declared 'noreturn' should not r= eturn=20 [-Winvalid-noreturn]". Bruno, how about if we go back to how verify.h did 'assume' before the re= cent=20 clang-related changes? That would avoid the complaints. It might cost us = a few=20 nanoseconds of performance with clang-generated code but that's no big de= al. And=20 anyway, clang ought to get fixed to generate the slightly-better code wit= h=20 'verify.h' just as it was. #include #include extern void error (int, int, char const *, ...); _Noreturn void f (void) { error (1, 1, "error"); assume (0); }