From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 104439 invoked by alias); 22 Apr 2016 16:05:58 -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 104408 invoked by uid 89); 22 Apr 2016 16:05:57 -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=priorities, Hx-languages-length:1480 X-HELO: mail-pa0-f54.google.com Received: from mail-pa0-f54.google.com (HELO mail-pa0-f54.google.com) (209.85.220.54) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES128-GCM-SHA256 encrypted) ESMTPS; Fri, 22 Apr 2016 16:05:47 +0000 Received: by mail-pa0-f54.google.com with SMTP id zm5so41039137pac.0 for ; Fri, 22 Apr 2016 09:05:47 -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=9g989dxFNC+lAzS1usUBBSD+wMwIDkKz0eNc3fRysNo=; b=DdseJ3nooocQPvaBpcprH4TKUQo55ByrhIn4xnfnZLDQbmMTOrd+gd2tBRbxeaeYfH 6y/t91djnfdKU/3E/b7mVTu9apCAwN5aplyvo27S9ioOfN3lhxx3K2DEBjQiG9Sqn2WB 3w4xNVLoHSJOvOK7NEnuHDeOXVS1rmgKw/uTDu87nE9NrKlggvZWVpjARQoooqngssFP I834UYhGTEgO+9iiGVtP5q3WQL12Q1ht/FDyX7ppUAvaiZ+jbU7kHhPgFxL5V8v0VSLI EjGy8EDNQAa1Sd51CtrgXNNAw2bhnqCZ1BKrjpcyXjy7JXp3akJ0qiQE5HqVwPtcO8Ws hv8w== X-Gm-Message-State: AOPr4FU08vhh54F3XLiFxDkiW5AGvclEdnhXvKivXxcDjj0L/kSuIgiZA3pWbis2IQUR7g== X-Received: by 10.66.251.132 with SMTP id zk4mr29687601pac.50.1461341145460; Fri, 22 Apr 2016 09:05:45 -0700 (PDT) Received: from E107787-LIN (gcc1-power7.osuosl.org. [140.211.15.137]) by smtp.gmail.com with ESMTPSA id 187sm9367830pff.66.2016.04.22.09.05.43 (version=TLS1_2 cipher=AES128-SHA bits=128/128); Fri, 22 Apr 2016 09:05:44 -0700 (PDT) From: Yao Qi To: Pedro Alves Cc: Yao Qi , gdb-patches@sourceware.org Subject: Re: [PATCH 1/2] Use -fno-asynchronous-unwind-tables if C program is compiled without debug info on x86 References: <1461052220-10149-1-git-send-email-yao.qi@linaro.org> <1461052220-10149-2-git-send-email-yao.qi@linaro.org> <57163425.1070505@redhat.com> <86wpnsiskw.fsf@gmail.com> <571A197A.5030201@redhat.com> <86y485hgdx.fsf@gmail.com> <571A36CB.8060001@redhat.com> Date: Fri, 22 Apr 2016 16:05:00 -0000 In-Reply-To: <571A36CB.8060001@redhat.com> (Pedro Alves's message of "Fri, 22 Apr 2016 15:35:55 +0100") Message-ID: <86lh45hbng.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/msg00535.txt.bz2 Pedro Alves writes: > Instead of a name, maybe a frame-unwinder-class enum, based on=20 > https://sourceware.org/bugzilla/show_bug.cgi?id=3D19288#c13 > > ~~~~~~~~~~~~~~~ > - The "Accurate unwinders" > > These would be the DWARF / x64 SEH based ones. > > - JIT unwinders=20 > > Python/Guile unwind API unwinders, and also the C JIT-reader > API unwinder, in jit.c. > > - Fallback prologue unwinders > ~~~~~~~~~~~~~~~ > > Then it could be "required" instead of "preferred", which would > catch problems with the unwinder's sniffer as well. I am fine on this, but I don't think this is helpful to PR 19288. What we need in PR 19288 is a dynamic list of unwinders (based on priority), so that user can change the orders of unwinders in the list by changing their priorities. IIUC, in PR 19288, each unwinder works well if the desired unwinder in the chain is selected. The problem is the desired unwinder can't be selected in the chain. If we want to handle these two problems together, we need command line interface to set and change the priorities of unwinders or classes of unwinders. This would be useful to PR 19288. We can set priority to -1 or 0 to disable the unwinder completely. However, my concern on this feature is that we may expose too much to the user, and usually, it is tricky and sensitive on changing the order of unwinders. --=20 Yao (=E9=BD=90=E5=B0=A7)