From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 52411 invoked by alias); 2 Apr 2015 08:58:25 -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 52345 invoked by uid 89); 2 Apr 2015 08:58:25 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.5 required=5.0 tests=AWL,BAYES_00,KAM_LAZY_DOMAIN_SECURITY,SPF_HELO_PASS,T_RP_MATCHES_RCVD autolearn=no version=3.3.2 X-HELO: mx1.redhat.com Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES256-GCM-SHA384 encrypted) ESMTPS; Thu, 02 Apr 2015 08:58:24 +0000 Received: from int-mx14.intmail.prod.int.phx2.redhat.com (int-mx14.intmail.prod.int.phx2.redhat.com [10.5.11.27]) by mx1.redhat.com (Postfix) with ESMTPS id 3ACD1A0774; Thu, 2 Apr 2015 08:58:23 +0000 (UTC) Received: from [127.0.0.1] (ovpn01.gateway.prod.ext.ams2.redhat.com [10.39.146.11]) by int-mx14.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id t328wKss010355; Thu, 2 Apr 2015 04:58:21 -0400 Message-ID: <551D04AC.7000206@redhat.com> Date: Thu, 02 Apr 2015 08:58:00 -0000 From: Pedro Alves User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.5.0 MIME-Version: 1.0 To: Peter Schauer CC: Yao Qi , gdb-patches@sourceware.org, Ulrich Weigand Subject: Re: [rfc, spu] Don't call set_gdbarch_cannot_step_breakpoint in spu_gdbarch_init References: <201504012035.t31KZ6xi004942@licht.localdomain> In-Reply-To: <201504012035.t31KZ6xi004942@licht.localdomain> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit X-SW-Source: 2015-04/txt/msg00098.txt.bz2 On 04/01/2015 09:35 PM, Peter Schauer wrote: > This was needed for alpha OSF/1. > > Back then it was the only architecture which would not ptrace step > over an inserted breakpoint, causing an infinite loop while trying > to single step over an inserted breakpoint. OOC, do you recall whether the infinite loop was that the step didn't make progress, and gdb would continuously issue a single-step forever, or whether the infinite loop was all in the kernel? > > The diff back then was > > + #ifdef CANNOT_STEP_BREAKPOINT > + /* If the target doesn't support stepping over a breakpoint, simply > + continue, we will then hit the breakpoint anyway. */ > + if (step && breakpoints_inserted && breakpoint_here_p (read_pc ())) > + step = 0; > + #endif > > I do not know if GDB ever tries to ptrace step over an inserted > breakpoint nowadays, sorry. It does in some cases when we have a signal to deliver at the same time we are trying to step over a breakpoint. Look for "signal arrived while stepping over" in infrun.c. > Meanwhile the alpha OSF/1 port is dead anyways... The setting ended up done for all alpha ports today though, in: alpha-tdep.c: set_gdbarch_cannot_step_breakpoint (gdbarch, 1); OSF/1 is gone, but we still support Alpha GNU/Linux, which is also taking that code path,. If this was OSF/1 specific, then we could get rid of that too, and then get rid of gdbarch_cannot_step_breakpoint completely. Anyone have access to Alpha GNU/Linux to try that out? Ulrich, any idea why cannot_step_breakpoint was ever needed for the SPU? Thanks, Pedro Alves