From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 4578 invoked by alias); 14 Apr 2016 10:29:41 -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 3992 invoked by uid 89); 14 Apr 2016 10:29:41 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.6 required=5.0 tests=AWL,BAYES_00,FREEMAIL_FROM,RCVD_IN_DNSWL_LOW,SPF_PASS autolearn=ham version=3.3.2 spammy=Advanced, HX-Received:10.66.63.104, ABC, family X-HELO: mail-pa0-f49.google.com Received: from mail-pa0-f49.google.com (HELO mail-pa0-f49.google.com) (209.85.220.49) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES128-GCM-SHA256 encrypted) ESMTPS; Thu, 14 Apr 2016 10:29:31 +0000 Received: by mail-pa0-f49.google.com with SMTP id er2so15277480pad.3 for ; Thu, 14 Apr 2016 03:29:30 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:references:date:in-reply-to :message-id:user-agent:mime-version:content-transfer-encoding; bh=/rQjmte32WE9Z2c9pDcEG6NvjH5/preQsF3OLWNnKWU=; b=Dtsik0mazpT1doERwxiI+9Jy1CwillC2S+WSV+YTQ2HCZCruKpOUG/gvJOLInan33d yULVRIKbKuWz0HXhNvB8hBsvNeUB3DKwFcpyFAFWWRF1WlBvouYSmpuIRTalEh+htJap NL3GRhisWu8NpZdNGYAC8DTYtNAKSR0Wy3xKFkzSWT8JfdPjUeoDUCxH45LRZbREgVyG yDMp5UyX47BSH71E3QeUVTZrMSFpqWWQ+cR7RYx1Nq/TldA4f3sqo6+WV6Zw16D1wiBc Ib5/cPAUhJh/ZYELic4982mUBeq3Z0HjoNAfHx3WyZHq6qk0h2z0SRpKteZMCA82fGoO O2cQ== X-Gm-Message-State: AOPr4FXqs1QG4n9c0i+4EF4w+f8dHsPNmXIdt+NUIV6dl6gCU54iifPHp7mlxB2hbaOHcQ== X-Received: by 10.66.63.104 with SMTP id f8mr19890399pas.109.1460629769297; Thu, 14 Apr 2016 03:29:29 -0700 (PDT) Received: from E107787-LIN (gcc1-power7.osuosl.org. [140.211.15.137]) by smtp.gmail.com with ESMTPSA id g28sm56959625pfd.25.2016.04.14.03.29.26 (version=TLS1_2 cipher=AES128-SHA bits=128/128); Thu, 14 Apr 2016 03:29:28 -0700 (PDT) From: Yao Qi To: Walfred Tedeschi Cc: palves@redhat.com, brobecker@adacore.com, gdb-patches@sourceware.org Subject: Re: [PATCH V2 0/2] Split tdesc_(amd64|i386)_mpx into tdesc(amd64|i386)_mpx_* and tdesc(amd64|i386)_avx_mpx_* References: <1457025942-23711-1-git-send-email-walfred.tedeschi@intel.com> Date: Thu, 14 Apr 2016 10:29:00 -0000 In-Reply-To: <1457025942-23711-1-git-send-email-walfred.tedeschi@intel.com> (Walfred Tedeschi's message of "Thu, 3 Mar 2016 18:25:40 +0100") Message-ID: <864mb4mqkm.fsf@gmail.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-IsSubscribed: yes X-SW-Source: 2016-04/txt/msg00322.txt.bz2 Walfred Tedeschi writes: > CPU features can occur in any combination. The current assumption that=20 > feature "A" implies in feature "B" does not necessarily hold. >=20=20 > This patch series construct an additional combination of the Intel(R)=20 > Memory Protection Extensions (MPX) with Intel(R) Advanced Vector=20 > Extensions (AVX). First of all, I am not against your patches. Just think a little more after reading them... This reveals a problem in gdb target description. It doesn't scale very well if processors have multiple different features, and features can be combined differently. A processor family has three features A, B, and C, and each processor implementation may have one, two or three of these features. In gdb target description, we need to have many *.xml and *.c files, for these combinations like, A, B, C, AB, AC, BC, and ABC. The root cause is that target description are static and pre-generated. If the target description can be generated dynamically according to the cpuid or AT_HWCAP, that would be simpler. In this way, we only have to define target descriptions for feature A, B, and C, and GDB/GDBserver combine them together in the runtime. --=20 Yao (=E9=BD=90=E5=B0=A7)