From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 23865 invoked by alias); 31 Jan 2003 01:25:46 -0000 Mailing-List: contact gcc-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Archive: List-Post: List-Help: Sender: gcc-owner@gcc.gnu.org Received: (qmail 23821 invoked from network); 31 Jan 2003 01:25:45 -0000 Received: from unknown (HELO mail-out2.apple.com) (17.254.0.51) by 172.16.49.205 with SMTP; 31 Jan 2003 01:25:45 -0000 Received: from mailgate1.apple.com (A17-128-100-225.apple.com [17.128.100.225]) by mail-out2.apple.com (8.11.3/8.11.3) with ESMTP id h0V1PbI19290 for ; Thu, 30 Jan 2003 17:25:37 -0800 (PST) Received: from scv1.apple.com (scv1.apple.com) by mailgate1.apple.com (Content Technologies SMTPRS 4.2.5) with ESMTP id ; Thu, 30 Jan 2003 17:25:37 -0800 Received: from apple.com (mrs1.apple.com [17.201.24.248]) by scv1.apple.com (8.11.3/8.11.3) with ESMTP id h0V1Pas02475; Thu, 30 Jan 2003 17:25:36 -0800 (PST) Date: Fri, 31 Jan 2003 02:08:00 -0000 Subject: Re: GCC 3.3, GCC 3.4 Content-Type: text/plain; charset=US-ASCII; format=flowed Mime-Version: 1.0 (Apple Message framework v551) Cc: Phil Edwards , Mike Stump , Benjamin Kosnik , gcc@gcc.gnu.org To: Neil Booth From: Mike Stump In-Reply-To: <20030130235920.GA14300@daikokuya.co.uk> Message-Id: <812EC35C-34BA-11D7-8309-003065A77310@apple.com> Content-Transfer-Encoding: 7bit X-SW-Source: 2003-01/txt/msg01718.txt.bz2 On Thursday, January 30, 2003, at 03:59 PM, Neil Booth wrote: >> I detect the note of frustration, but I think this is an experiment >> worth making. Say, allow --with-gc=none (re-allow?) to choose >> ggc-none.c, >> and see what happens. >> >> Perhaps the compiler need only turn on GC at all once a threshold >> number >> of... something... has been passed. (Statements? Tree nodes created? >> Dunno.) > > Whatever we do, the worst thing is to make GCC non-deterministic. > > Someone suggested this (Geoff?) and someone else (Mike I think!) > pointed > out what a bad idea this was. Scream now, as last I knew Geoff wanted to check the paging activity on the system to dynamically tune the number. Last I knew, we planned a mode where one could get the deterministic results, though, unfortunately, if one wants to debug a problem, and when they ask for determinism, if the problem goes away, we are sol. Geoff's contention I think is that this is unlikely, and that there should be few bugs of these sorts. I'm happy to try it out and see, we can decide later if it really is a pain or not. The biggest hit for me is, I must select the deterministic mode, as otherwise, I cannot breakpoint on address equality, which I like so very much. I'm trying to envision the documentation: --please-make-compiler-deterministic Eliminates non-determinism from the compiler. :-) It that an -f option, or an -m option?