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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D754BC7EE2F for ; Wed, 1 Mar 2023 18:04:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229719AbjCASEb (ORCPT ); Wed, 1 Mar 2023 13:04:31 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35148 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229525AbjCASE3 (ORCPT ); Wed, 1 Mar 2023 13:04:29 -0500 Received: from mx0b-0031df01.pphosted.com (mx0b-0031df01.pphosted.com [205.220.180.131]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 007C31990; Wed, 1 Mar 2023 10:04:27 -0800 (PST) Received: from pps.filterd (m0279868.ppops.net [127.0.0.1]) by mx0a-0031df01.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 321H5UYW003769; Wed, 1 Mar 2023 18:04:02 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=quicinc.com; h=message-id : date : mime-version : subject : to : cc : references : from : in-reply-to : content-type : content-transfer-encoding; s=qcppdkim1; bh=Q0zdVJDzr22M4csdbIqednl0Qpg1rg7ayxs2WRyps/I=; b=AjuCYAkKdUR9NyWHt4x+5kAB+Zyj8Uon5tWafHvcNsdWinkDjTmhg7CWdMOG3IMa71PH 2Hsp0XvVc/PkqrIZDGIHzvIDRRahJdazIOB4KBjW3PK99MMe4gVH0dJVadvVY2qYf5Kk Tzo2vV7GF0h9i2xXqA3QJ6v5R8kVLZKLAQUXB23T/o9IGhRveUmAjtOHiK4g/4Qo+L7e NmDL/pjg2LG3pWmv7zYfw1ACfRoxqlE4lwhitGOEMiV6zsGW2n6PYCOipnfP7udAWDxJ KMwIZeIaLh8JmM81HcgBZSgJVVDpjcXrIT7WVt5q9pJKHNOdG2lnmSZY80LyaVrE++ji Xg== Received: from nalasppmta01.qualcomm.com (Global_NAT1.qualcomm.com [129.46.96.20]) by mx0a-0031df01.pphosted.com (PPS) with ESMTPS id 3p2aspr6s9-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 01 Mar 2023 18:04:02 +0000 Received: from nalasex01c.na.qualcomm.com (nalasex01c.na.qualcomm.com [10.47.97.35]) by NALASPPMTA01.qualcomm.com (8.17.1.5/8.17.1.5) with ESMTPS id 321I419T029012 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 1 Mar 2023 18:04:01 GMT Received: from [10.110.81.49] (10.80.80.8) by nalasex01c.na.qualcomm.com (10.47.97.35) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.986.41; Wed, 1 Mar 2023 10:03:59 -0800 Message-ID: <41d287fa-3a0a-cac6-4595-ad47ef873d79@quicinc.com> Date: Wed, 1 Mar 2023 10:03:58 -0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.6.1 Subject: Re: [PATCH v2 0/2] Validating UAPI backwards compatibility To: Nick Desaulniers CC: Masahiro Yamada , Nathan Chancellor , Nicolas Schier , , , , , "Greg Kroah-Hartman" , Randy Dunlap , Arnd Bergmann , Bjorn Andersson , Todd Kjos , Matthias Maennich , Giuliano Procida , , , Jordan Crouse , Trilok Soni , "Satya Durga Srinivasu Prabhala" , Elliot Berman References: <20230301075402.4578-1-quic_johmoo@quicinc.com> Content-Language: en-US From: John Moon In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.80.80.8] X-ClientProxiedBy: nasanex01b.na.qualcomm.com (10.46.141.250) To nalasex01c.na.qualcomm.com (10.47.97.35) X-QCInternal: smtphost X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=5800 signatures=585085 X-Proofpoint-GUID: cbtX0ENhKptLgq19VBYYROGSZhnEkE_y X-Proofpoint-ORIG-GUID: cbtX0ENhKptLgq19VBYYROGSZhnEkE_y X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.219,Aquarius:18.0.942,Hydra:6.0.573,FMLib:17.11.170.22 definitions=2023-03-01_13,2023-03-01_03,2023-02-09_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=0 impostorscore=0 mlxscore=0 bulkscore=0 phishscore=0 mlxlogscore=999 malwarescore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 priorityscore=1501 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2212070000 definitions=main-2303010144 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 3/1/2023 9:50 AM, Nick Desaulniers wrote: > On Tue, Feb 28, 2023 at 11:54 PM John Moon wrote: >> >> Currently, the script works with gcc. It generates output like this when >> a backwards-incompatible change is made to a UAPI header: >> >> !!! ABI differences detected in include/uapi/linux/acct.h (compared to >> file at HEAD^1) !!! >> >> [C] 'struct acct' changed: >> type size changed from 512 to 544 (in bits) >> 1 data member insertion: >> '__u32 new_val', at offset 512 (in bits) at acct.h:71:1 >> >> 0/1 UAPI header file changes are backwards compatible >> UAPI header ABI check failed >> >> However, we have not had success with clang. It seems clang is more >> aggressive in optimizing dead code away (no matter which options we >> pass). Therefore, no ABI differences are found. > > Hi John, > Do you have the list of bugs you've filed upstream against clang wrt. > information missing when using `-fno-eliminate-unused-debug-types`? > > https://github.com/llvm/llvm-project/issues is the issue tracker. > > Seeing a strong participant in both the Android and LLVM ecosystems > supply scripts that lack clang support...raises eyebrows. We have not filed a bug with upstream clang since we're not sure it's *not* and issue on our end. Giuliano Procida (CC'd) has tested the script with clang 13 and 14 and GCC 10, 11 and 12 and got the expected diff. If it's convenient for anyone testing this script to give it a whirl with clang and report back, it could help us determine if there's a real issue with clang support. :)