Call for Discussion: New Project: Leyden

[Jiangli Zhou]

On Thu, May 21, 2020 at 3:48 PM <mark.reinhold at oracle.com> wrote:

> 2020/5/18 15:43:34 -0700, jianglizhou at google.com:
> > Didn't see this discussion until today. I think this will be welcomed by
> > Java developers! How do we participate in the project and coordinate?
>
> I’ll shortly start the CFV to create the Project.  Once the Project
> exists, your participation will be most welcome!
>

Sounds great!


>
> > I have been experimenting with preserving pre-initialized classes (at
> build
> > time) as part of the CDS archive image. Class pre-initialization can help
> > field and method pre-resolution and generate better AOT code. Here is a
> class
> > pre-resolution & pre-initialization proposal
> > <
> https://docs.google.com/document/d/17RV8W6iqJj9HhjGSO9k1IXfs_9lvHDNgxxr8pFoeDys/edit?usp=sharing
> >
> > that enhances
> > the existing Hotspot heap archiving and provides more general support to
> > pre-initialize classes and preserve static field values for both JDK
> > classes and application classes (loaded by system class loader).
>
> Sorry, but for IP clarity could you please either post that document to
> cr.openjdk.java.net or enter it into a JBS issue?  (Likewise for the
> slides that you mention later on.)
>

I've posted the docs to cr.openjdk.java.net:

Design doc:
http://cr.openjdk.java.net/~jiangli/Leyden/Java%20Class%20Pre-resolution%20and%20Pre-initialization%20(OpenJDK).pdf
Slides:
http://cr.openjdk.java.net/~jiangli/Leyden/Selectively%20Pre-initializing%20and%20Preserving%20Java%20Classes%20(OpenJDK).pdf

Will also attach them to JBS as suggested.


> >                                                                  I
> adopted
> > the annotation approach in the proposal, after comparing it to other
> > alternatives, please see details in the design doc.
>
> In a prototype, using an annotation to identify pre-initializable
> classes is fine.  In the long run, however, we’ll likely wind up with a
> keyword since annotations must not be used to change language semantics.
>

That sounds workable. The underlying heap object archiving mechanism can
support different approaches (list, interface, annotation, keyword, etc) as
an 'indicator' for pre-initializing & preserving classes and static fields.

Really excited about the project!

Best regards,
Jiangli


> - Mark
>