On Sunday, 15 January 2012 at 0:41 , Michał Bendowski wrote:

> On Saturday, 14 January 2012 at 22:28 , Maciej Fijalkowski wrote:
>  
> > On Sat, Jan 14, 2012 at 11:18 PM, Michał Bendowski <[email protected] 
> > (mailto:[email protected])> wrote:
> > >  
> > >  
> > > On Friday, 13 January 2012 at 16:02 , Antonio Cuni wrote:
> > >  
> > > > Hello Michał,
> > > >  
> > > > On 01/12/2012 09:24 PM, Michał Bendowski wrote:
> > > > > Hello everyone,
> > > > >  
> > > > > Back in the summer I asked on this mailing list if there's interest 
> > > > > in moving the JVM backend forward. Back then there was some 
> > > > > enthusiasm, so I got back to it when I had the chance, which 
> > > > > unfortunately was a few months later. The suggestion back then was to 
> > > > > look into using JPype to integrate more closely with Java-side code, 
> > > > > and that's what I would like to do.
> > > > >  
> > > > > But before that, I noticed that the JVM backend fails to translate 
> > > > > the standard interpreter and spent some time lately getting to know 
> > > > > the code and trying to get it to work. What I have right now is a 
> > > > > version that outputs valid Jasmin files, which unfortunately still 
> > > > > contain some invalid bytecodes (longs vs ints from what I've seen, 
> > > > > I'll look into it next).
> > > >  
> > > >  
> > > > the long vs int problems are likely due to the fact that you are 
> > > > translating
> > > > on a 64 bit machine. The translator toolchain assumes that the "native" 
> > > > long
> > > > type of the target platform is the same as the source one, but this is 
> > > > not the
> > > > case if you are targeting the JVM (where long is 32 bit) on a 64 bit 
> > > > linux
> > > > (where long is 64 bit).
> > > >  
> > > > This problem is not easily solvable, so my suggestion is just to 
> > > > translate
> > > > pypy-jvm inside a 32bit chroot for now.
> > > >  
> > > > > It would be awesome if someone could take a look at my changes. 
> > > > > What's the best way to submit them? Bitbucket pull requests? They 
> > > > > will need to go through some review - do you have a workflow for that?
> > > >  
> > > >  
> > > > we don't have any precise workflow, although a bitbucket pull request 
> > > > might be
> > > > the easiest thing to do. I'll be glad to review it.
> > > >  
> > > > > Here's a short list of stuff I found and fixed (hopefully):
> > > > > - support the ll_getlength method of StringBuilders in ootype,
> > > > > - make compute_unique_id work on built-ins (StringBuilders again).
> > > >  
> > > >  
> > > >  
> > > >  
> > > >  
> > > >  
> > > >  
> > > > not sure what you mean here. What is the relation between 
> > > > compute_unique_id
> > > > and StringBuilder?
> > > >  
> > > > > - provide oo implementations (or stubs) for pypy__rotateLeft, 
> > > > > pypy__longlong2float etc.
> > > > > - handle rffi.SHORT and rffi.INT showing up in graphs. For now I try 
> > > > > to emit something that makes sense (seemed easier), but the right 
> > > > > solution is probably to see if the code in question (rbigint, rsha) 
> > > > > can be implemented on the java level.
> > > >  
> > > >  
> > > >  
> > > >  
> > > >  
> > > >  
> > > >  
> > > > yes, this is another issue that has been around for a long time. In 
> > > > theory, we
> > > > would like to be able to write per-backend specific code which 
> > > > overrides the
> > > > default implementation. This would be useful for rbigint and rsha, but 
> > > > also
> > > > e.g. for rlib.streamio. However, we never wrote the infrastructure to 
> > > > do that.
> > > >  
> > > > > - handle the jit_is_virtual opcode - I had no idea how to "safely 
> > > > > ignore" it for now, is False the safe answer?
> > > >  
> > > >  
> > > > yes. Look at translator/c/funcgen.py:848: this is how jit_is_virtual is
> > > > implemented by the C backend, you can see that it always returns 0/
> > > >  
> > > > > I hope someone can help me to submit the changes and maybe guide with 
> > > > > further work.
> > > >  
> > > >  
> > > > Please put your work on bitbucket, I'll review it. I'd greatly 
> > > > appreciate if
> > > > you committed small checkins (one for each fix/feature you are doing) 
> > > > instead
> > > > of one giant commit with all the changes :-)
> > >  
> > >  
> > >  
> > >  
> > >  
> > >  
> > >  
> > > OK, I got myself a 32bit environment and created the pull request (. I'll 
> > > be grateful for any feedback. One thing I didn't do was to create 
> > > regression tests against the problems I found - I didn't know where to 
> > > put the tests and what (and how) exactly to test. If you can shed some 
> > > light on it, that would be awesome.
> >  
> >  
> > Lack of tests is a no-no in PyPy world :) Look how current tests are
> > implemented in pypy/translator/jvm/test/ and either extend those or
> > the base classes. You run them using py.test (which comes included
> > with pypy), refer to py.test documentation for details
>  
>  
>  
>  
> I'll look into it, looks like a whole new codebase to grep through (and I 
> already found a bug in my code). I'll create a new pull request when I'm 
> ready with the tests :)
OK - I have create another pull requests here: 
https://bitbucket.org/pypy/pypy/pull-request/20/improvements-to-the-jvm-backend-this-time

The previous one should be rejected/deleted, it seems impossible from my side. 
I will be grateful for comments about the changes.

Michał  


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