From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 13941 invoked by alias); 10 Jun 2004 17:12:09 -0000 Mailing-List: contact gdb-help@sources.redhat.com; run by ezmlm Precedence: bulk List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-owner@sources.redhat.com Received: (qmail 13874 invoked from network); 10 Jun 2004 17:12:02 -0000 Received: from unknown (209.128.65.135) by sourceware.org with QMTP; 10 Jun 2004 17:12:02 -0000 Received: (qmail 30916 invoked by uid 10); 10 Jun 2004 17:12:01 -0000 Received: (qmail 28283 invoked by uid 500); 10 Jun 2004 17:11:53 -0000 From: Ian Lance Taylor To: Andrew Haley Cc: tromey@redhat.com, Daniel Jacobowitz , java@gcc.gnu.org, gdb@sources.redhat.com Subject: Re: Binary Compatibility: debug info for compiled Java programs References: <16582.65277.81118.189889@cuddles.cambridge.redhat.com> <20040609130859.GA7514@nevyn.them.org> <16583.3516.604885.805420@cuddles.cambridge.redhat.com> <20040609132951.GA8017@nevyn.them.org> <16583.4773.74100.735457@cuddles.cambridge.redhat.com> <20040609221710.GA16922@nevyn.them.org> <87ise0bc8y.fsf@fleche.redhat.com> <20040610163718.GA24803@nevyn.them.org> <874qpjbcju.fsf@fleche.redhat.com> <16584.37526.974458.647364@cuddles.cambridge.redhat.com> Date: Thu, 10 Jun 2004 17:12:00 -0000 In-Reply-To: <16584.37526.974458.647364@cuddles.cambridge.redhat.com> Message-ID: User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.3 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-SW-Source: 2004-06/txt/msg00100.txt.bz2 Andrew Haley writes: > > By the way, Tom and Andrew, I meant to ask, but I forgot: would it > > make sense to build the numeric otables and atables for the common > > case, and then recompute only when required? > > That's possibly true, but you'd somehow have to discover that > something had changed, and I'm not sure how you'd do that without > doing the lookups. It seems to me that you could hash the relevant information for each relevant class and store it in the defining class and in the loaded class. When you load the binary, check the hashes, and recompute if they differ. > > I have to think that the common case is pretty darn common--I'm > > sure people don't spend all their time loading classes into > > different hierarchies. > > What is very common is for people to distribute Java binaries without > specifying the exact versions of the classes they depend on. So, it's > normal for the run-time library environment of a Java program to be > different from the compile-time environment. The whole idea of binary > compatibility is to make this possible. On the other hand, at during compile/edit/debug, the compile-time and run-time environment should be similar. Hmmm, I suppose that could be a good way to hide bugs, though. Ian