Re: Contributions of work on Jikes RVM with GNU Classpath

[Mark Wielaard]

Hi (I have added the GNU Classpath mailinglist to the CC),

On Thu, 2002-11-21 at 17:19, Julian Dolby wrote:
> 
>  Inside IBM, we have been doing further work on integrating Jikes RVM
> and the GNU Classpath libraries, based on the original port from John
> Leuner.  We have been doing work on both the technical front of
> getting the system to behave and the legal front to allow us to
> contribute changes to the GNU Classpath code.  Both fronts have
> now reached a point where we can check into developerWorks and
> contribute to GNU Classpath a combined set of changes that result in a
> version Jikes RVM built with the GNU Classpath libraries that passes
> all of our internal sanity tests and even---in some
> configurations---runs most of the Eclipse Java-based IDE.

Impressive! I really look forward to running Eclipse using a free VM and
the GNU Classpath libraries.

>  We will check our Jikes RVM changes into the developerWorks
> repository in the immediate future, but there are three different
> kinds of changes needed in the GNU Classpath code, two of which we
> can contribute and one which---for legal reasons---it is easier if we
> simply say what needs to happen.
> 
>  1) We have made a few changes in the interface between the generic
>     GNU Classpath code and the VM-provided support code.  These
>     changes consist of adding a few methods to the VMSystem class to
>     allow Jikes RVM to provide Java implemetations of stuff currently
>     declared native in GNU Classpath.
> 
>      This does not in any way require that GNU Classpath use any of
>     the Jikes RVM build process (preprocessors, etc); we have simply
>     moved some native declarations from API classes into the VM* support
>     classes and put indirections in the API classes.

Good. This looks like what I was planning to do to make the VM* classes
more flexible.

>  2) In the course of running the Eclipse Java-based IDE on Jikes RVM
>     and GNU Classpath, we found bugs in both Jikes RVM and GNU
>     Classpath.  We will make the Jikes RVM fixes ourselves, and will
>     contribute the GNU Classpath fixes.

Thanks. How many changes are we talking about?

>  3) The one change we needed to make that we cannot---for legal
>     reasons---easily contribute is to javax.naming; while running
>     Eclipse we came across incompletenesses in the GNU Classpath code
>     base, which we worked around by merging the javax.naming code from
>     GCJ into the GNU Classpath code base.  We simply removed the code
>     currently in the GNU Classpath code base and replaced it wholesale
>     with the code from GCJ.  That combined code compiled immediately
>     and worked at least as far as we needed it to.
> 
>      We do not want to suck the GCJ code base into IBM and then send
>     it back to GNU Classpath.  This would be highly problematic for us
>     legally.  Ideally, someone at GNU Classpath can merge these code
>     bases independently for us.

This is no problem. I once started merging in bits of javax.naming from
libgcj into Classpath. But decided that it was not documented enough to
be really useful. But documenting takes a lot of time and I lost
interest a bit after documenting the classes that are currently in the
GNU Classpath tree. But I guess that if there is a need it is better to
have to non-documented classes in Classpath then let people. I will
merge these classes in the next couple of days into the GNU Classpath
CVS tree.

>  We would be happy to contribute our changes in any manner people at
> GNU Classpath find convenient.  We can send you diffs in any format or
> simply a tarball of the GNU Classpath tree we have here.  Please let
> me know what you would find most useful.

It is probably a good idea to make a new release of GNU Classpath first
(say in the next two weeks). So that we have a clear point from which to
start merging in the changes. The last GNU Classpath release was a
couple of months ago and a lot of changes have been made. I will propose
a release schedule on the GNU Classpath list later today since I wanted
to have a new release anyway soon. But it depends a bit on the number of
changes that you have, if there are not that many then maybe waiting a
little longer with a new release might be a better option.

The best way to do the actual merge/patches is by trying to identify
independent changes and post them on the classpath mailinglist so people
can discuss them. Just sending a big tarball or one gaint patch/diff
makes it hard to analyse what changed and for what reason. If you send
patches to the mailinglist please try to create diffs against the
current CVS tree and use unidiffs (cvs diff -u). If splitting up the
changes is not possible you can always make a unidiff of the changes and
add it to the Patch Manager http://savannah.gnu.org/patch/?group_id=85
but then it might take a (long) while before the patches will actually
be merged.

Brian Jones can also give one of you CVS write access to the GNU
Classpath tree if you want.

>  Thanks to John Leuner for getting the whole Jikes RVM on GNU
> Classpath work started and doing the initial port.

Yes. Thanks a lot John!

Cheers,

Mark