# Wednesday, March 3, 2004
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Object Model Mapping Part 3

A brief update on the progress and some random thoughts on remapping. Today I got classpath.dll to build (and verify) for the first time using the new remapping infrastructure. Finally some progress. However, there is still some more work to do before it runs again.

Part of the new model is that there are now two different type wrappers (the internal class that contains the meta data of an IKVM type) for the remapped types. There is one type wrapper that is used during static compilation (RemapperTypeWrapper) and another one that is used during at runtime (CompiledTypeWrapper, also used for normal (i.e. non-remapped) statically compiled classes). The advantage of this is that there is less overhead at runtime and the code is also a bit less complex. This is also the final step in an invisible process that has been going on for a long time. It is now no longer possible to run IKVM without a statically compiled classpath.dll (it hasn't been possible for a while, but theoretically it could have been made to work). When I just got started, there was no static compiler yet and the only way for it to work was to load all classes dynamically, after the static compiler started to work, support for dynamically loading the core classes began to degenerate. That degeneration is now final and there is no way back ;-)

What's next?

More metadata needs to be emitted on the remapped types and CompiledTypeWrapper needs to be changed to understand it. The code needs to be cleaned up. I'm not sure yet, but I think a lot of complexity can be removed now. Virtual method invocation needs to be optimized. At the moment all virtual method call to remapped types go through the helper methods, but this is only needed is the reference type is not know to be a Java subclass. For example, calling java.lang.Object.toString() on a java.lang.Object reference requires the call to go through the helper method, but calling java.lang.Object.toString() on java.lang.Math (this is just a random example) doesn't need to go through the helper method.

Of course, there are also various loose ends that need to be tied up, but I think I'm on track to have a working version sometime next week.


Patrik posted an overview of the FOSDEM Java talks. It also includes links to the slides for some of the talks.

Wednesday, March 3, 2004 8:59:25 PM (W. Europe Standard Time, UTC+01:00)  #    Comments [0] Tracked by:
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