[pypy-dev] JVM backend - status and future work possibilities?

[Bo Chen]

Anto,

Thanks for your patient. I will read the code of RPython first.

Bo Chen

On Sat, May 21, 2011 at 6:22 PM, Antonio Cuni <anto.cuni at gmail.com> wrote:

> On 16/05/11 17:10, Bo Chen wrote:
> > Anto,
>
> Hello Bo,
> (I've CCed pypy-dev again, please click "reply all" to make sure the list
> is
> included)
>
> > Is there any advice on reading the source code of the pypy?
>
> that's a hard question, it depends what is your goal. My experience is that
> if
> you have a clear goal and start by writing a failing test, then it's easier
> to
> follow what's going on in that particular case.
>
> Personally, I love to put pdb.set_trace() here and there to watch the
> execution of the code in the pieces I'm interested in.
>
> > And here is my question, the JVM backend is to invoke java classes in
> pypy or
> > translate the python binary to java binary, or both?
>
> The JVM backend translates RPython source code into JVM bytecode (actually,
> it
> generates a textual form of the JVM bytecode, which is then assembled by
> jasmin).
>
> Currently, you cannot create/call Java entities from RPython code, but as I
> explained in the earlier emails, this is a prerequisite feature before
> doing
> the rest of the work.
>
> > There is a prototype use JPype, is this mean the JVM backend turn the
> java
> > binary code into the python's.
>
> no. JPype allows to call Java code from CPython, but there is no
> translation
> of java into python involved.
>
> Note that JPype would be used only for tests, and not for the actual
> translation.  This is because the RPython code can be either run on top of
> cpython (for testing) or translated to jvm code.  JPype (or equivalent) is
> needed for the first case
>
> For the second case, JPype does not play any role.  What it's needed is to
> teach the RPython toolchain how to deal with Java classes.  Remind that the
> JVM backend already emits JVM bytecode, so it's "enough" to teach the
> RPython
> toolchain to transform e.g. "rjvm.System.out.println" into the
> corresponding
> invokestatic bytecode.
>
> > And only the JIT complier will transfer the python to java.
>
> no JIT is involved at this point.  I think it's better to keep the JIT out
> of
> this particular discussion, to avoid confusion.
>
> > And the Point(1) would be not only just use the JPype, but also need
> > implement totally?
>
> see my explanation above, hoping that it answer your question.
>
> ciao,
> Anto
>
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