From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 116491 invoked by alias); 28 Feb 2020 13:51:04 -0000 Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org Received: (qmail 116430 invoked by uid 89); 28 Feb 2020 13:51:04 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-8.5 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_NONE,SPF_PASS autolearn=ham version=3.3.1 spammy=H*f:sk:9c256b2, HX-Languages-Length:2378, 26AM, 26am X-HELO: mail-qt1-f195.google.com Received: from mail-qt1-f195.google.com (HELO mail-qt1-f195.google.com) (209.85.160.195) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Fri, 28 Feb 2020 13:51:02 +0000 Received: by mail-qt1-f195.google.com with SMTP id y3so1503454qtv.12 for ; Fri, 28 Feb 2020 05:51:02 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=O3I9Yi7t+3eF/orPNUe9lhB2zCe0nrs3zYr+XRL0rCs=; b=HubMTri+/rJfv7++e0l1Adw3kQhIdUEoievif3CA1cO/Y6Gb6iZwSgZdT/USifh2+P rBMHsmi0EPIZ0s09BDJ3ltD6ggqtw0kzSQD83xy2L7VwGFCZ7x7vVDDC/eGmJ2YJMX2x RtGw1YPiURqqxlvXtUMqFqYwpAiCY116uq/5O+Lj+8yhvJ3PUMFNxDV+TwzfCUXFNLBP eQ6RhBEiue4YIY8KTZY5ksR57uiqQIyrPU/NyH/uEPLQ8L5VJTfwVLqEN2752ZOX/qCE daWwVBiOgJAikTmC2JQlDX+sEtcP2I8JIrqxXs/hCY2ELUOwszYCwNIhEoCTTrN2fZVe peyQ== Return-Path: Received: from [192.168.0.185] ([191.34.159.98]) by smtp.gmail.com with ESMTPSA id d9sm4940267qth.34.2020.02.28.05.50.56 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 28 Feb 2020 05:50:59 -0800 (PST) Subject: Re: [Regression] [PATCH] Do not print empty-group regs when printing general ones To: Shahab Vahedi Cc: Christian Biesinger , Shahab Vahedi , "gdb-patches@sourceware.org" , Claudiu Zissulescu , Francois Bedard , Andrew Burgess References: <20200120155315.30333-1-shahab.vahedi@gmail.com> <75f76108-a233-6fce-66a2-86452371e1be@linaro.org> <9c256b27-4a00-8830-46e2-934922e39cc2@linaro.org> <20200228133618.GA3269@gmail.com> From: Luis Machado Message-ID: <51718427-72e2-ce12-7181-26ec9b38d947@linaro.org> Date: Fri, 28 Feb 2020 13:51:00 -0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 MIME-Version: 1.0 In-Reply-To: <20200228133618.GA3269@gmail.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-IsSubscribed: yes X-SW-Source: 2020-02/txt/msg01044.txt.bz2 On 2/28/20 10:36 AM, Shahab Vahedi wrote: > On Fri, Feb 28, 2020 at 10:31:26AM -0300, Luis Machado wrote: >> >> >> On 2/28/20 10:22 AM, Christian Biesinger wrote: >>> On Fri, Feb 28, 2020 at 7:08 AM Luis Machado wrote: >>>> >>>> On 1/31/20 7:34 AM, Shahab Vahedi wrote: >>>>> This patch was reviewed once (as OK): >>>>> https://sourceware.org/ml/gdb-patches/2020-01/msg00613.html >>>>> >>>>> Could someone review/merge it? >>>>> >>>>> >>>>> Cheers, >>>>> Shahab >>>>> >>>> >>>> FTR, this has broken general register printing for ARM/AArch64. Now >>>> "info reg" shows nothing. >>>> >>>> Given there are already remote stubs, probes and gdbservers running out >>>> there, this is an undesirable change to have. >>>> >>>> I had an IRC chat with Christian and he pointed me at some documentation >>>> stating empty-group registers should not be printed, but i think this is >>>> a case where the implementation has diverged from the documentation. >>>> >>>> https://sourceware.org/gdb/current/onlinedocs/gdb/Target-Description-Format.html#Target-Description-Format >>>> >>>> We could probably patch up any non-standard target description XML's >>>> from now on, but the existing behavior may have to be preserved. >>> >>> Most targets under features/ do not specify group="general" in their >>> XML files for anything (only S/390 does); it seems like that should >>> maybe be fixed either way? >> >> I agree. > > The documentation [1] says: > If no group is specified, GDB will not display the register in info registers > > [1] > https://sourceware.org/gdb/onlinedocs/gdb/Target-Description-Format.html#Target-Description-Format > That's valid, but unfortunately it doesn't change the fact the existing code is breaking backwards compatibility with the installed base. As we discussed on IRC, this is code put together in early 2007 and hasn't been touched since, apart from a small change in 2017 to cope with arbitrary group strings. Plus we have plenty of existing target descriptions that do not honor explicitly setting a register group. With that said, i think the documentation would have a lower priority in this regard. We should fix the existing target descriptions to be more strict with the group names, but the old behavior would have to be honored IMO.