From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gproxy4-pub.mail.unifiedlayer.com (gproxy4-pub.mail.unifiedlayer.com [69.89.23.142]) by sourceware.org (Postfix) with ESMTPS id 8D1AB388E82B for ; Wed, 16 Mar 2022 17:23:18 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 8D1AB388E82B Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=tromey.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=tromey.com Received: from cmgw13.mail.unifiedlayer.com (unknown [10.0.90.128]) by progateway6.mail.pro1.eigbox.com (Postfix) with ESMTP id F2CD210047FB6 for ; Wed, 16 Mar 2022 17:23:17 +0000 (UTC) Received: from box5379.bluehost.com ([162.241.216.53]) by cmsmtp with ESMTP id UXMjnIZLZY8ycUXMjnuTqT; Wed, 16 Mar 2022 17:23:17 +0000 X-Authority-Reason: nr=8 X-Authority-Analysis: v=2.4 cv=ff9od2cF c=1 sm=1 tr=0 ts=62321d05 a=ApxJNpeYhEAb1aAlGBBbmA==:117 a=ApxJNpeYhEAb1aAlGBBbmA==:17 a=dLZJa+xiwSxG16/P+YVxDGlgEgI=:19 a=o8Y5sQTvuykA:10:nop_rcvd_month_year a=Qbun_eYptAEA:10:endurance_base64_authed_username_1 a=CCpqsmhAAAAA:8 a=05KejWv9md2MUbc_zmwA:9 a=ul9cdbp4aOFLsgKbc677:22 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=tromey.com; s=default; h=Content-Type:MIME-Version:Message-ID:In-Reply-To:Date:References :Subject:Cc:To:From:Sender:Reply-To:Content-Transfer-Encoding:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=FqYyja1M/uQJ4VqmcowVMvtZAC6964PW5zlmqqEC+X4=; b=E99/wScgl07BbTDDyfKQBYwD26 hvcVqvqMjFkW6r+0jBKKcF5kCoq/cV7CW2pU7JCmh8yv0DWHJa/MPDuA64FbPzYCIxt2Rpf5BwV7R PBCDNXIhheZCtf1v+pK90NkX9; Received: from 71-211-175-224.hlrn.qwest.net ([71.211.175.224]:37984 helo=murgatroyd) by box5379.bluehost.com with esmtpsa (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1nUXMj-004HKg-9U; Wed, 16 Mar 2022 11:23:17 -0600 From: Tom Tromey To: Andrew Burgess via Gdb-patches Cc: Andrew Burgess Subject: Re: [PATCHv2] gdb/x86: handle stap probe arguments in xmm registers References: <20220315105446.3348835-1-aburgess@redhat.com> <20220316141316.465293-1-aburgess@redhat.com> X-Attribution: Tom Date: Wed, 16 Mar 2022 11:23:16 -0600 In-Reply-To: <20220316141316.465293-1-aburgess@redhat.com> (Andrew Burgess via Gdb-patches's message of "Wed, 16 Mar 2022 14:13:16 +0000") Message-ID: <871qz1ke0r.fsf@tromey.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - box5379.bluehost.com X-AntiAbuse: Original Domain - sourceware.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - tromey.com X-BWhitelist: no X-Source-IP: 71.211.175.224 X-Source-L: No X-Exim-ID: 1nUXMj-004HKg-9U X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: 71-211-175-224.hlrn.qwest.net (murgatroyd) [71.211.175.224]:37984 X-Source-Auth: tom+tromey.com X-Email-Count: 1 X-Source-Cap: ZWx5bnJvYmk7ZWx5bnJvYmk7Ym94NTM3OS5ibHVlaG9zdC5jb20= X-Local-Domain: yes X-Spam-Status: No, score=-3024.6 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, JMQ_SPF_NEUTRAL, RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H2, SPF_HELO_NONE, SPF_PASS, TXREP, T_SCC_BODY_TEXT_LINE autolearn=no autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: gdb-patches@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gdb-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 16 Mar 2022 17:23:19 -0000 >>>>> "Andrew" == Andrew Burgess via Gdb-patches writes: Andrew> Notice that for both of these probes, the first argument is a uint64_t Andrew> stored in the xmm1 register. I wonder how much the ideas in here overlap with Zoran's still-pending patches to rework the DWARF expression evaluator. IIUC his work involved some of this same sort of extraction. However, since yours is via the stap probe stuff, there probably isn't much opportunity for code reuse. Andrew> architectures this method would fist possibly adjust the register fist->first Andrew> Finally, as this patch adds a new operation type, then I need to Andrew> consider how to generate an agent expression for the new operation Andrew> type. Andrew> I have kicked the can down the road a bit on this. This seems completely fine to me. Andrew> This is because GDB doesn't currently support placing non-scalar types Andrew> on the agent expression evaluation stack. Solving this is clearly Andrew> related to the original problem, but feels a bit like a second Andrew> problem. I'd like to get feedback on whether my approach to solving Andrew> the original problem is acceptable or not before I start looking at Andrew> how to handle xmm registers within agent expressions. Note that there are many things that can't be represented in agent expressions. I recall filing a bug report about this -- there are some DWARF expressions that can't be translated, and IIRC, floating point isn't handled at all. So, I wouldn't worry too much about this. My sense is that tracepoints aren't used a whole lot. Anyway your patch looked reasonable to me. Tom