Review request for JDK-8025435

[Marcus Lagergren]

Thank you Christian!

This looks very interesting indeed! I’ll read properly on the plane to JavaOne! I like the annotation based approach very much

/M


On 23 Sep 2014, at 14:06, Christian Humer <christian.humer at gmail.com> wrote:

> Hi Marcus,
> 
> We have recently published a paper at GPCE on a systematic approach to declare specializations for any kind of operations [1]. 
> Some of the ideas that we've gathered there over the last two years might also be applicable to your approach.
> 
> [1] http://lafo.ssw.uni-linz.ac.at/papers/2014_GPCE_TruffleDSL.pdf
> 
> - Christian Humer
> 
> 
> 
> From: Marcus Lagergren <marcus.lagergren at oracle.com>
> Subject: Review request for JDK-8025435
> Date: 22 Sep 2014 16:38:48 GMT+2
> To: "nashorn-dev at openjdk.java.net nashorn-dev at openjdk.java.net" <nashorn-dev at openjdk.java.net>
> 
> Please review JDK-8025435 at http://cr.openjdk.java.net/~lagergren/8025435/
> 
> https://bugs.openjdk.java.net/browse/JDK-8025435
> 
> This is the framework for optimistic builtin functions. Summary of work
> 
> * Introduced SpecializedFunction and SpecializedFunction.Guard for fast optimistic implementations
> * Modified ScriptFunction so that it picks the best specialization first, and checks if it can link using the above datastructures
> * Modified Nasgen to recognize the SpecializedFunction and its annotations
> * Implemented fast versions of Array.push/pop and String.charCodeAt as proof of concepts
> * Added a switchpoint based rather than guard based framework for invalidation of builtin functions (on a per context basis), to get rid of previous guard overhead
> * Added primitive linkage without proto filter as long as builtins acting upon them haven’t been rewritten
> * Currently there is support for invalidation of both entire builtins e.g. Array.prototype = something and proerties Array.prototype.push = something, but the granularity right now, to save switchpoints, uses the same switchpoint for an entire builtin and all its properties, as any other cases are rare. Granularity can easily be increased by adding keys to the builtinSwitchPoints table in the Context
> * Prefer to invalidate callsite by ClassCastException and failed type checks instead of explicit guards.
> 
> I’m saving further specializations for later dates.
> 
> Added various microbenchmarks to prove performance of the implementations of the current functions.
> 
> Before patch:
> 
> zann:make marcus$ sh ../bin/runopt.sh ../test/examples/push-pop-benchmark.js
> 18997 ms
> 
> Verified OK - result is correct
> 
> After patch:
> 
> zann:make marcus$ sh ../bin/runopt.sh ../test/examples/push-pop-benchmark.js
> 2327 ms
> 
> Verified OK - result is correct
> zann:make marcus$ d8 ../test/examples/push-pop-benchmark.js
> 9672 ms
> 
> Verified OK - result is correct
> 
> Similar benchmark exists for charCodeAt - my other proof of concept, which runs about 5x faster too. 
> 
> Test and test262 are clean after some horror corner cases with lengths and array like objects.
> 
> Regards
> Marcus
> 
>