From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 45240 invoked by alias); 4 Oct 2017 21:25:25 -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 45071 invoked by uid 89); 4 Oct 2017 21:25:25 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.7 required=5.0 tests=AWL,BAYES_00,FREEMAIL_FROM,RCVD_IN_DNSWL_NONE,RCVD_IN_SORBS_SPAM,SPF_PASS autolearn=no version=3.3.2 spammy=HTo:U*macro, Overall, our X-HELO: mail-qk0-f195.google.com Received: from mail-qk0-f195.google.com (HELO mail-qk0-f195.google.com) (209.85.220.195) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Wed, 04 Oct 2017 21:25:23 +0000 Received: by mail-qk0-f195.google.com with SMTP id z12so5706259qkb.0 for ; Wed, 04 Oct 2017 14:25:23 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=Jwndh35BrujqvJzlby58CTZ3tECIEscn67ZdYK6Exf0=; b=Ewr+J0IALPSylLlErGB7/7F9McLdnL0ShvnbGeCLLfu0A0GO2hYPQM3z+NwyAjN6Fp iFqqXurTDmq0z0RaIEJaJKv+zEPQgbOpnl0TyOvoy9kRp17SYtTS98RVSjBR3SX/NtKr tE0opr+jhJU7R3aKS0A2Sgkdl51yo1IsfC0+ZN5/nu2tsGIJqPBtXHoV4jg2RernYdyP H4wA1aJ71lEyfo1OhI3PIdAqdhPWXVQyniGHCFrQu4wAmCYqhhwMchJqkjsOFqK41y5q xX3grkVNSxn9hRmlWT7dmSSHK03yDD/T9sTZ34/CYsjaNDmxU0d5Dl4gsS1CSrCjUXNJ 2rfA== X-Gm-Message-State: AMCzsaVaaYdvlZnVBI/r/C/3ajbyXy47Cwwa8sqQQdS4hEYD60vaRmTl I14UQ1OJlNYN9BtoFT7I76aLpruEfrByKR+VdXY= X-Google-Smtp-Source: AOwi7QCSRBYTpVq93ffBwMy2W/rMyqHdeaKPRApLvhAjBhMrZwoDU0Vuc6s9YY3RevMdbxw6/DWkIVc7zXLS/dp8oIA= X-Received: by 10.55.76.196 with SMTP id z187mr27698405qka.100.1507152322125; Wed, 04 Oct 2017 14:25:22 -0700 (PDT) MIME-Version: 1.0 Received: by 10.12.153.236 with HTTP; Wed, 4 Oct 2017 14:25:21 -0700 (PDT) In-Reply-To: References: <20161017155133.A9B8711C257@oc8523832656.ibm.com> From: Yao Qi Date: Wed, 04 Oct 2017 21:25:00 -0000 Message-ID: Subject: Re: [RFC 2/3] Record function descriptor address instead of function address in value To: "Maciej W. Rozycki" Cc: Ulrich Weigand , Bhushan Attarde , "gdb-patches@sourceware.org" Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-IsSubscribed: yes X-SW-Source: 2017-10/txt/msg00096.txt.bz2 On Tue, Oct 3, 2017 at 7:12 PM, Maciej W. Rozycki wrote: > Hi Yao, > > On Fri, 28 Oct 2016, Yao Qi wrote: > >> > Overall I like the proposal and if this goes forward I will see if we= can >> > adapt the MIPS backend to use this approach as well, addressing the is= sues >> > we still have remaining, such as confusing instruction addresses and w= rong >> > instruction data shown with `disass /r'. We have a little complicatio= n in >> > that we have the ISA bit set in line information, so that would have t= o be >> > stripped in DWARF record processing, but it should be much easier to do >> > with a single hook in place than the complicated processing now requir= ed >> > to copy ISA bit annotation from the symbol table (msymbols), the hooks= to >> > handle which we'll then be able to drop from our DWARF machinery. >> >> At the very beginning, I wanted to follow the MIPS approach in ARM, >> but I realized some issues when writing the patch. Then, I switched to >> the approach I am proposing in this thread. If the ISA bit plus function >> address is regarded as a function descriptor, this approach should be >> able to handle all of them (ppc64, arm and mips) correctly (and >> cleanly, I hope). > > Have you made any progress with your solution? I saw Ulrich had concerns > and it's been a while, silent, since we discussed it. Meanwhile we have > started discovering corner case issues with compressed code disassembly, > which I believe your change would fix. So we'd rather avoid creating more > hooks (hacks) addressing these issues, only to remove them again once your > obviously more promising solution has gone in. > Hi Maciej, I had some ideas to address Ulrich's concerns/comments, IIRC. It is still on my TODO, but it was interrupted by GDBserver software single step last year, and SVE/target description this year :( I still have 3 - 4 things I need to finish by next release. I hope that I can pick it up again next year. --=20 Yao (=E9=BD=90=E5=B0=A7)