On Jan 31, 2010, at 11:19 PM, Charles Oliver Nutter wrote: > The other use case, which I did not attempt, was in regenerating call > sites a la the DLR's DynamicSite logic (which repeatedly regenerates a > call site with a series of instanceof checks, to specialize the call > paths iteratively). Again, InvokeDynamic potentially handles this > better?
It is designed to do this; e.g., see section 5.3 in my VMIL paper. One bit of engineering that needs investigation is how to build up DLR-style call sites incrementally without doing quadratic recompilation work. >> The uses you and Charlie point out are less important that they seemed at >> first for two reasons: >> >> 1. Method handles provide a better replacement for the swarm of tiny classes. >> >> 2. Hotspot is in the process of weaning itself off of perm gen. One of the >> main features of perm-gen is that its objects never move except during full >> GC, and the code cache relied on this invariant until just last year, with >> the 'ScavengeRootsInCode' changes. > > If permgen goes away, there's still the classloader-rooting problem > that requires constructing a new classloader for every tiny class you > want to be GCable. If JRuby, for example, wanted to start "tiering" > our optimization phases, we'd have to use scads and scads of > classloaders to ensure the old method bodies could go away. So that > use case is still alive and well. Yes; this is probably the enduring use of anonk as it stands. Interestingly, I just learned (from a link on Lambda-the-ultimate) that Microsoft just put the equivalent feature into .NET 4. It's called Collectible Assemblies: http://msdn.microsoft.com/en-us/library/dd554932%28VS.100%29.aspx -- John _______________________________________________ mlvm-dev mailing list mlvm-dev@openjdk.java.net http://mail.openjdk.java.net/mailman/listinfo/mlvm-dev
