From owner-freebsd-arm@FreeBSD.ORG Wed Aug 20 17:19:49 2014 Return-Path: Delivered-To: freebsd-arm@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id BB863FF6; Wed, 20 Aug 2014 17:19:49 +0000 (UTC) Received: from mail-la0-x22e.google.com (mail-la0-x22e.google.com [IPv6:2a00:1450:4010:c03::22e]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 0F5E539E0; Wed, 20 Aug 2014 17:19:48 +0000 (UTC) Received: by mail-la0-f46.google.com with SMTP id b8so7423820lan.5 for ; Wed, 20 Aug 2014 10:19:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=content-type:mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=yQ11qGcTR2GCedzydwFi3dFKhnRoGzDyaJEBTrt4r+s=; b=t/z6l5wEP/SK8WL45OU9k+4aQtDduU1vn7rTvTDfjkRHe1S+ln2QvvfwtPIggbxrBp XFTRqDs9CWT7LQKi099OUmm1XWCe1jg4hRm7hQuj5vW6r7dT2f5Z7eHDJX9aqcgVRw1g hObp4luoGk0vQMdBH6PHWhob7IyYSZIBYcKDe1UtoDbwHDyTH+qNKLjQW2gU+fzVJFUu c2uwLRJazZCREQUybIBftSfT1DWezgfW1+mI0oi9cdbGMF6JwV3MygsJP+dH7nRZNLfZ BGAhRJihlzJudA9NwPaAXkJC4uXZl4Ma5DOaIKfoVLiEM3sYflPcFElgemBd3S4J3ekn sxHA== X-Received: by 10.112.165.68 with SMTP id yw4mr42463698lbb.5.1408555186938; Wed, 20 Aug 2014 10:19:46 -0700 (PDT) Received: from [192.168.1.105] (c-d135e155.556-1-64736c11.cust.bredbandsbolaget.se. [85.225.53.209]) by mx.google.com with ESMTPSA id wv7sm14768286lac.30.2014.08.20.10.19.44 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Wed, 20 Aug 2014 10:19:45 -0700 (PDT) Content-Type: text/plain; charset=iso-8859-7 Mime-Version: 1.0 (Mac OS X Mail 7.3 \(1878.6\)) Subject: Re: C++ exceptions in freebsd-arm doesn't seem to work From: Olavi Kumpulainen In-Reply-To: <1408472517.56408.659.camel@revolution.hippie.lan> Date: Wed, 20 Aug 2014 19:19:41 +0200 Content-Transfer-Encoding: quoted-printable Message-Id: References: <1405809318.85788.35.camel@revolution.hippie.lan> <1406063473.71975.8.camel@revolution.hippie.lan> <53D2CFBE.3040207@fgznet.ch> <834BA562-84ED-425C-9D61-0A235A28A94A@gmail.com> <1408472517.56408.659.camel@revolution.hippie.lan> To: Ian Lepore X-Mailer: Apple Mail (2.1878.6) Cc: freebsd-arm@freebsd.org X-BeenThere: freebsd-arm@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: "Porting FreeBSD to ARM processors." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 20 Aug 2014 17:19:49 -0000 On 19 Aug 2014, at 20:21 , Ian Lepore wrote: > On Tue, 2014-08-19 at 19:40 +0200, Olavi Kumpulainen wrote: >> On 25 Jul 2014, at 23:44 , Andreas Tobler = wrote: >>=20 >>> On 22.07.14 23:11, Ian Lepore wrote: >>>> On Sat, 2014-07-19 at 16:35 -0600, Ian Lepore wrote: >>>>> On Sat, 2014-06-07 at 14:12 +0200, Olavi Kumpulainen wrote: >>>>>> [c++ exceptions don't work and related discussion] >>>>>=20 >>>>> I checked in a partial fix for c++ exception handling in r268893. = It >>>>> fixes the specific problem you detailed above, which was = essentially >>>>> that the __gnu_Unwind_Find_exidx() function was not available in = any >>>>> shared library, making the unwinder fall back to using the = __exidx_start >>>>> and end symbols, which are only valid in a statically-linked app. >>>>>=20 >>>>> With the new function in place, exceptions are closer to working = with >>>>> gcc 4.2.1, but still don't work with clang. With gcc, some things = work >>>>> and some things don't. For example if you throw an exception and = in the >>>>> same function have a catch with the right specific type it = segfaults, >>>>> but a catch(...) will catch it without problems. But you can = catch an >>>>> exception by type if the catch is in a function higher up the call = chain >>>>> from the place it was thrown. >>>>>=20 >>>>> We're continuing to debug this at $work, and welcome any input if = anyone >>>>> else makes progress with it. Right now we still don't know = whether the >>>>> segfaults are because of bad unwinder library code or bad unwind = data >>>>> emitted by gcc. (I sure hope it's the library, because that's = easier to >>>>> fix.) >>>>>=20 >>>>> On the clang front, it has been said that c++ exceptions work in = clang >>>>> 3.5, so we tried the clang-devel port, and it didn't just work. = But it >>>>> turns out that port hasn't been updated for quite a while, so we = may not >>>>> have tested the code that's supposed to work right. While trying = that I >>>>> discovered that clang 3.5 isn't scheduled for release for about = another >>>>> year, so that really isn't a viable solution for anyone with = near-term >>>>> needs, unless the required changes can be cherry-picked and = brought into >>>>> our version of 3.4. >>>>>=20 >>>>> -- Ian >>>>=20 >>>> Another update to this... today I committed r268993 and r268994, = and now >>>> I believe arm eabi c++ exceptions are fully working with gcc. I = haven't >>>> run an extensive test suite, but all the test cases we've been = using at >>>> $work to debug this now work correctly. >>>=20 >>> Thank you! Confirmed. My test cases which are working with gcc-4.10 = are now also working with the system gcc, 4.2.1. >>> I totally forgot about this change. I have it in my local gcc tree = since a while but I forgot about..... >>>=20 >>> Andreas >>>=20 >>>=20 >>=20 >> Please excuse my late reply. I=A2ve been away from keyboard for a = while. >>=20 >> I back-ported r268893, r268993 and r268994 to stable/10 for = beaglebone. C++ exceptions works for static builds, but not for binaries = linked to shared libs. >>=20 >> Since this seems to work ok in HEAD, I=A2m obviously missing = something. Do any of you guys have any ideas? >>=20 >> Cheers >>=20 >=20 > I'm not sure what you mean by "backported to stable/10", I merged all > the necessary changes to stable-10 as r269792 on Aug 10. Are you > working with a checkout from earlier than that? If so, just updating > should fix it for you. >=20 > -- Ian >=20 >=20 Updating to stable-10 as of today didn=A2t help. I=A2m running a clean = checkout except for a couple of drivers in the kernel. This makes me think I have a bad src.conf - How shall I configure the = build for this to work? /Olavi