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 X-Spam-Level: X-Spam-Status: No, score=-11.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3D8E0C433DB for ; Thu, 28 Jan 2021 13:49:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D76206146D for ; Thu, 28 Jan 2021 13:49:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231220AbhA1NtX (ORCPT ); Thu, 28 Jan 2021 08:49:23 -0500 Received: from mail.kernel.org ([198.145.29.99]:40948 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231168AbhA1NtW (ORCPT ); Thu, 28 Jan 2021 08:49:22 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 2AD7B64DD6; Thu, 28 Jan 2021 13:48:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1611841721; bh=jxPJ0qG9WPpvkas9lFLuFsdz8oHGmnXbPvAJlZcudl4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=YBpfIaPfIQcDabXyRsuMQVrMmXe0BI05ojqQNPmHP8nrZ2GE5Uxp9sh5wJPSoYnK3 fQ4B7UACrMGF+XE3vCKs6eqZBMuhnge1+NoZi/S38n571V+9UlveBH5pxDMOQ57Kvf 3cywYWPnZfxxXTJ+pN3sp6TQ0tH7qkHQhEV1JhPSB0aVRKzen2iAq6pyX7wBznTXtC 9iIK0VT3/zpdkD/YAfVQ77BFiHwrQZsPHJTyINfq+M39ADDCGRw00EUt0tvWtFMbfd RR8QBMs9w5FwhlZLvvgwXIyPlidJrcCC6el6uDiqaCCqUxbHOSkuQBnJcbj3pmiukK ypyyxNqaruRvQ== Received: by quaco.ghostprotocols.net (Postfix, from userid 1000) id A2FFA40513; Thu, 28 Jan 2021 10:48:37 -0300 (-03) Date: Thu, 28 Jan 2021 10:48:37 -0300 From: Arnaldo Carvalho de Melo To: Daniel =?iso-8859-1?Q?P=2E_Berrang=E9?= Cc: Mark Wielaard , dwarves@vger.kernel.org Subject: Re: [PATCH/RFC] Re: DWARF5 DW_AT_data_bit_offset Message-ID: <20210128134837.GE775562@kernel.org> References: <5ee85ca6e3b06b07c83b150912fbcfc1a4c13e19.camel@klomp.org> <20201002211819.GA127275@kernel.org> <20210121113516.GA8492@wildebeest.org> <20210128121122.GA775562@kernel.org> <20210128125443.GI3832029@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20210128125443.GI3832029@redhat.com> X-Url: http://acmel.wordpress.com Precedence: bulk List-ID: X-Mailing-List: dwarves@vger.kernel.org Em Thu, Jan 28, 2021 at 12:54:43PM +0000, Daniel P. Berrangé escreveu: > On Thu, Jan 28, 2021 at 09:11:22AM -0300, Arnaldo Carvalho de Melo wrote: > > Em Thu, Jan 21, 2021 at 12:35:16PM +0100, Mark Wielaard escreveu: > > > On Fri, Oct 02, 2020 at 06:18:19PM -0300, Arnaldo Carvalho de Melo wrote: > > > > Em Fri, Oct 02, 2020 at 06:11:06PM +0200, Mark Wielaard escreveu: > > > > > Seems pahole with a recent version of elfutils libdw already handles > > > > > most DWARF5 encodings. One thing it doesn't handle yet is > > > > > DW_AT_data_bit_offset (this is actually a DWARF4 thing, but gcc only > > > > > emits it for -gdwarf-5). > > > > > > > > > > > $ gcc -gdwarf-5 -c bf.c > > > > > $ ./pahole ./bf.o > > > > > DW_AT_<0xd>=0x21 > > > > > DW_AT_<0xd>=0x21 > > > > > DW_AT_<0xd>=0x21 > > > > > struct pea { > > > > > int type; /* 0 4 */ > > > > > static long int a; /* 0 0 */ > > > > > static long int b; /* 0 0 */ > > > > > static long int c; /* 0 0 */ > > > > > > > > > > /* size: 8, cachelines: 1, members: 1, static members: 3 */ > > > > > /* padding: 4 */ > > > > > /* last cacheline: 8 bytes */ > > > > > }; > > > > > > > Note that GCC11 might default to DWARF5. > > > > > > Thanks for the detailed report, I'm releasing v1.18 right now, will look > > > > into that for v1.19. > > > > > Note that GCC11 indeed just switched to producing DWARF5 by default. > > > It is not released yet, but already in stage4 and Fedora will start > > > doing a mass-rebuild with it soon to shake out the last remaining bugs. > > > > So, 1.20 will have the fix below, please check if what is in: > > > > https://git.kernel.org/pub/scm/devel/pahole/pahole.git/log/?h=DW_AT_data_bit_offset > > > > Fixes it for you, the cset with all the tests performed is this one: > > > > https://git.kernel.org/pub/scm/devel/pahole/pahole.git/commit/?h=DW_AT_data_bit_offset&id=a77f039bb49bc97badf938049245f013fe3de4aa > > > > Now looking at https://bugzilla.redhat.com/show_bug.cgi?id=1919965 ... > > The XDR generated code example I give in that bug *does* appear > to be fixed when using your DW_AT_data_bit_offset branch. Thanks for checking, I'll double check on my side now, got sidetracked in the last hour with perf patch processing :-) - Arnaldo