From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 112663 invoked by alias); 22 Aug 2018 15:35:21 -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 112652 invoked by uid 89); 22 Aug 2018 15:35:20 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-1.9 required=5.0 tests=BAYES_00,KAM_SHORT,SPF_PASS autolearn=ham version=3.3.2 spammy=buettner, Buettner, his, UD:php X-HELO: mx1.suse.de Received: from mx2.suse.de (HELO mx1.suse.de) (195.135.220.15) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Wed, 22 Aug 2018 15:35:19 +0000 Received: from relay1.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 8F8F5AF5C; Wed, 22 Aug 2018 15:35:17 +0000 (UTC) Subject: Re: [PATCH 1/3] Add support for DW_OP_GNU_variable_value To: Kevin Buettner References: <20180802210405.5c04ca7a@pinnacle.lan> <20180802211754.40a529c2@pinnacle.lan> <87o9ej1emk.fsf@tromey.com> <20180818133158.7e5b4dcb@pinnacle.lan> Cc: gdb-patches@sourceware.org, Richard Biener , Jakub Jelinek From: Tom de Vries Message-ID: <93529546-71b0-4268-880a-79b00062ecd2@suse.de> Date: Wed, 22 Aug 2018 15:35:00 -0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20180818133158.7e5b4dcb@pinnacle.lan> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-IsSubscribed: yes X-SW-Source: 2018-08/txt/msg00536.txt.bz2 On 08/18/2018 10:31 PM, Kevin Buettner wrote: > This patch adds support for DW_OP_GNU_variable_value to GDB. > > Jakub Jelinek provides a fairly expansive discussion of this DWARF > expression opcode in his GCC patch... > > https://gcc.gnu.org/ml/gcc-patches/2017-02/msg01499.html > > It has also been proposed for addition to the DWARF Standard: > > http://www.dwarfstd.org/ShowIssue.php?issue=161109.2 Hi, AFAIU from the discussion here ( https://gcc.gnu.org/ml/gcc-patches/2018-08/msg01351.html ) if: - a DW_OP_GNU_variable_value refers to a die 'a', and - there's a die 'b' with abstract_origin 'a' that does have a DW_AT_location, and - die 'b' is 'in scope' in an evaluation context, then the evaluation of DW_OP_GNU_variable_value 'a' should return the value found at the DW_AT_location of die 'b'. I've written a gcc demonstrator patch to generate code like this for VLAs, and found that gdb master (containing this patch series) does not support this. Is this further support of DW_OP_GNU_variable_value something you're currently working on, or plan to work on? Thanks, - Tom