From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 6572 invoked by alias); 19 May 2014 11:19:38 -0000 Mailing-List: contact gcc-bugs-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-bugs-owner@gcc.gnu.org Received: (qmail 6489 invoked by uid 48); 19 May 2014 11:19:31 -0000 From: "alexey.merzlyakov at samsung dot com" To: gcc-bugs@gcc.gnu.org Subject: [Bug libstdc++/60758] Infinite backtrace in __cxa_end_cleanup Date: Mon, 19 May 2014 11:19:00 -0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: libstdc++ X-Bugzilla-Version: 4.9.0 X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: alexey.merzlyakov at samsung dot com X-Bugzilla-Status: UNCONFIRMED X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-SW-Source: 2014-05/txt/msg01588.txt.bz2 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=60758 --- Comment #7 from Alexey Merzlyakov --- The problem does not appear for thumb2 targets. On older architectures (armv6 and below) in thumb-mode the LR indeed can not be used as argument of POP instruction. To support __cxa_end_cleanup backtracing on thumb1, we can make additional register operations before push/pop. But I guess, this will have a negative effect on __cxa_end_cleanup performance. So, I propose to preserve __cxa_end_cleanup backtracing on thumb2 architectures and revert it on thumb1.