I think it's better to make tab[i].invokeExact(...) a tailcall, so the loop will be part of the implementation, not part of the spec.
Rémi ----- Mail original ----- > De: "John Rose" <john.r.r...@oracle.com> > À: "Da Vinci Machine Project" <mlvm-dev@openjdk.java.net> > Envoyé: Jeudi 4 Août 2016 00:14:37 > Objet: Re: Threaded interpreter in Java > On Aug 3, 2016, at 1:22 PM, Remi Forax <fo...@univ-mlv.fr> wrote: >> >> Charles ask if we can make a fast register interpreter in Java, >> here is my take on a threaded-like interpreter >> >> https://gist.github.com/forax/f38b533e089217cfc4d0ae3c6e2de9c9 > > Nicely done. We were talking last night at dinner about making > bytecode interpreters go fast, and this is helpful. > > I think there may be a combinator here, for bytecode dispatch loops. > (This feels like the PIC combinator, both fundamental and tricky to get > right.) > A "bytecode" dispatch combinator might provide a pattern like the following: > > MethodHandle init, pred, step, fini, index; > @NonNull MethodHandle[] tab; > R dispatch(A… a) { > V v = init(a…); // one here; there might be many v… > while (pred(a…)) { > v = step(v, a…); > // execute one "instruction": > int i = index(v, a…); > tab[i].invokeExact(v, a…); > } > return fini(V, a…); > } > > The explicit table would be recopied internally to an @Stable array for > constant > folding. > The various index values could be tracked and turned into traces (or some > other > profile > driven structure) which would be compiled together, in specialized segments of > the unrolled > interpreter loop. > > Or maybe just the table lookup part alone makes a good combinator, to be > paired > with the loop combinators? > > Comments welcome… > > — John > > P.S. Another new RFE: > experimental hook for creating heisenboxes > https://bugs.openjdk.java.net/browse/JDK-8163133 > _______________________________________________ > mlvm-dev mailing list > mlvm-dev@openjdk.java.net > http://mail.openjdk.java.net/mailman/listinfo/mlvm-dev _______________________________________________ mlvm-dev mailing list mlvm-dev@openjdk.java.net http://mail.openjdk.java.net/mailman/listinfo/mlvm-dev
