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From sh...@computer.org
Subject Re: Other interesting papers and research
Date Sun, 22 May 2005 23:48:54 GMT
From: Steve Blackburn <Steve.Blackburn@anu.edu.au>

> > acoliver@apache.org wrote:
> >
> >> The approach of using C Compiler generated code rather than writing a
> >> full compiler appeals to me:
> >> http://www.csc.uvic.ca/~csc586a/papers/ertlgregg04.pdf
> >>
> >> I am curious on how well the approach performs compared to existing 
> >> JITs.

> They automatically build themselves
> simple JIT backends (by extracting fragments produced by the ahead of
> time compiler).  This sounds like a great way to achieve portability
> while achiving better performance than a conventional interpreter.

I guess it's a bit better or just comparable with a good interpreter.

In 1998, I have written such a JIT compiler concatinate code fragments
generated by GCC for each JVM instruction. Unfortunately, the JIT was
slightly slower than an interpreter in Sun's Classic VM. The
interpreter was written in x86 assembly language and implements
dynamic stack caching with 2 registers and 3 states. It performs much
better than the previous interpreter written in C.

Then I rewrote the JIT.

I am not very sure which is better for us, having a portable and so-so
baseline compiler or a good interpreter which is possibly less
portable than the compiler. There will be a trade off between memory
consumption, portability and so on.

  Kazuyuki Shudo	shudo@computer.org	http://www.shudo.net/

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