[Jikesrvm-core] object model refactoring

[David P G. <gr...@us...>]

Hi,

      As some of you know, David Bacon, Steve Fink, and I did some work at
the end of last year looking at alternate Java object models using Jikes
RVM.  The bulk of our implementation effort was in refactoring the
implementation of the JikesRVM object model to make it easier to change.
We'd like to contribute these changes back to the open source release of
JikesRVM to enable future experimentation in object models  The heart of
the change is that VM_ObjectLayoutConstants.java has been replaced by a
number of files that specify different aspects of the object model.
Needless to say, this impacts a number of pieces of the system (especially
all memory managers, including GCTk).
      It seems to me that the best way to do this would be to create a
branch in the open source CVS tree, apply our modifications to this branch,
and then ask people in the community to give feedback (and update GCTk as
required) before committing the changes to the main trunk of the open
source release.   Once the changes are complete, the system will be more
flexible and marginally cleaner.  But, the changes could be disruptive if
not managed correctly, therefore we want to go slowly and give the
community time to comment before the changes become final.

      Any comments or objections?

--dave