On Thu, Sep 27, 2012 at 6:33 PM, Ross Bamford <[email protected]> wrote: > On Thursday, 27 September 2012 18:28:40 UTC+1, Kristopher Micinski wrote: >> >> I agree that reflection will kill you. I actually hadn't thought >> about this, but it seems like there should be some sort of analysis to >> be able to get rid of the overly large reflective cost. Since inside >> your interpreter you will use a fairly fixed set of reflective calls, >> I would assume that for (example) long loops inside the program >> reflective calls could also be handled by the JIT (but, I assume they >> are *not*). Still, I agree that if the numbers are as you say, then >> having a compiler to Dex bytecode will help. >> > > To be fair, the implementation of the Dee VM could be improved somewhat in > this respect, although at the cost of flexibility. And in any event, > performance would still never reach that of Dex compiled scripts, since the > JIT cannot optimize reflection to the same extent as it does bytecode > because it can't make the same kind of assumptions as it can when the code > is statically compiled. >
Not necessarily true (and easier in a trace based JIT, I believe), if you can reason about the contents of strings and do proper linking. > (Caveat: I admit that I am basing this on the JVM - I simply don't know > enough about Android's JIT at this point to discuss it specifically). > I don't think that Dalvik's jit does this, however.. >> >> FYI from a research standpoint I am interested in doing something with >> this. I was going to work on implementing my own language for >> scripting apps, but I feel that would be a slight waste of time, as I >> really care more about the semantics within apps. >> >> So this is cool, I'd like to see if the language you have models the >> sort of thing I want to express, I believe it may. In any case, I >> will take a look at your compiler this weekend. >> > > Excellent. I would definitely welcome any feedback you have! > >> >> FYI during a project I work on we've written a compiler (really binary >> rewriter) for Dalvik bytecode in OCaml, though if you wanted to use it >> as part of your project you would have to properly port the ocaml >> runtime to Android (unless you could deal with doing development on a >> machine and then having it loaded to a phone all the time, which I >> probably would for my research purposes..). > > > This interests me. Is this a publicly-available project? If so, do you have > a link so I could take a look? > Not quite yet, but soon... It's described on our paper.. http://www.cs.umd.edu/~jfoster/papers/spsm12.pdf -- You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/android-developers?hl=en
