From owner-freebsd-arm@FreeBSD.ORG Tue Aug 19 18:22:00 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 6FF72D4C for ; Tue, 19 Aug 2014 18:22:00 +0000 (UTC) Received: from mho-01-ewr.mailhop.org (mho-03-ewr.mailhop.org [204.13.248.66]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 3F7A83FF6 for ; Tue, 19 Aug 2014 18:21:59 +0000 (UTC) Received: from [73.34.117.227] (helo=ilsoft.org) by mho-01-ewr.mailhop.org with esmtpsa (TLSv1:AES256-SHA:256) (Exim 4.72) (envelope-from ) id 1XJo2g-0001y8-NV; Tue, 19 Aug 2014 18:21:58 +0000 Received: from [172.22.42.240] (revolution.hippie.lan [172.22.42.240]) by ilsoft.org (8.14.9/8.14.9) with ESMTP id s7JILvgf051789; Tue, 19 Aug 2014 12:21:57 -0600 (MDT) (envelope-from ian@FreeBSD.org) X-Mail-Handler: Dyn Standard SMTP by Dyn X-Originating-IP: 73.34.117.227 X-Report-Abuse-To: abuse@dyndns.com (see http://www.dyndns.com/services/sendlabs/outbound_abuse.html for abuse reporting information) X-MHO-User: U2FsdGVkX1+rIXIrOEWskVk1bjqs4OCb X-Authentication-Warning: paranoia.hippie.lan: Host revolution.hippie.lan [172.22.42.240] claimed to be [172.22.42.240] Subject: Re: C++ exceptions in freebsd-arm doesn't seem to work From: Ian Lepore To: Olavi Kumpulainen In-Reply-To: <834BA562-84ED-425C-9D61-0A235A28A94A@gmail.com> 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> Content-Type: text/plain; charset="iso-8859-7" Date: Tue, 19 Aug 2014 12:21:57 -0600 Message-ID: <1408472517.56408.659.camel@revolution.hippie.lan> Mime-Version: 1.0 X-Mailer: Evolution 2.32.1 FreeBSD GNOME Team Port Content-Transfer-Encoding: quoted-printable X-MIME-Autoconverted: from 8bit to quoted-printable by ilsoft.org id s7JILvgf051789 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: Tue, 19 Aug 2014 18:22:00 -0000 On Tue, 2014-08-19 at 19:40 +0200, Olavi Kumpulainen wrote: > On 25 Jul 2014, at 23:44 , Andreas Tobler wro= te: >=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 essentiall= y > >>> that the __gnu_Unwind_Find_exidx() function was not available in an= y > >>> 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 wi= th > >>> 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 i= n the > >>> same function have a catch with the right specific type it segfault= s, > >>> 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 a= nyone > >>> 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 da= ta > >>> emitted by gcc. (I sure hope it's the library, because that's easi= er to > >>> fix.) > >>>=20 > >>> On the clang front, it has been said that c++ exceptions work in cl= ang > >>> 3.5, so we tried the clang-devel port, and it didn't just work. Bu= t it > >>> turns out that port hasn't been updated for quite a while, so we ma= y not > >>> have tested the code that's supposed to work right. While trying t= hat I > >>> discovered that clang 3.5 isn't scheduled for release for about ano= ther > >>> year, so that really isn't a viable solution for anyone with near-t= erm > >>> 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 hav= en'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 a= re now also working with the system gcc, 4.2.1. > > I totally forgot about this change. I have it in my local gcc tree si= nce 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 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. -- Ian