llvm dev - Nov 2008 - [LLVMdev] vmkit, jvm, newbie bytecode translation + jit question

Greetings,

I am searching for an alternative to sun's java implementation - one
that is not under gpl..

I've been reading the vmkit code for JNI..  And I notice that it is
not completely filled out yet... That's fine though, I see there is
filled in function like most of the non implemented functions..

Couple of questions:

Is the entire llvm required for java/cli vmkit to run?
I'm searching for a minimal install..

How big exactly is this binary installation.. (Not including java
libraries outside of the class path)

On a scale of 1 to 10.. How difficult do you think it would be to:
1.  Fill out JNI (I don't see this as a huge problem)
2.  Get it running on Win32 & WinCE..  (blech ?? blech blech ?? :-) )

Thanks again.

Your project looks great!!!

-tim

Hi Tim,

timprepscius wrote:
> Greetings,
>
> I am searching for an alternative to sun's java implementation - one
> that is not under gpl..
>
> I've been reading the vmkit code for JNI..  And I notice that it is
> not completely filled out yet... That's fine though, I see there is
> filled in function like most of the non implemented functions..
>
>   
Yeah, implementing the unimplemented functions is a matter of 
copy/pasting with simple editing.
> Couple of questions:
>
> Is the entire llvm required for java/cli vmkit to run?
> I'm searching for a minimal install..
>
>   
Here's what vmkit needs in order to create the exe:
jit nativecodegen scalaropts instrumentation ipa ipo

You could get rid of scalaropts, instrumentation, ipa and ipo if you 
don't want any optimizations on the LLVM IR.
> How big exactly is this binary installation.. (Not including java
> libraries outside of the class path)
>
>   
On my machine (linux/x86), the vmkit exe is about 13M.
> On a scale of 1 to 10.. How difficult do you think it would be to:
> 1.  Fill out JNI (I don't see this as a huge problem)
>   
1. Most is just copy-pasting. There are some JNI functions that play 
with IO and the classpath that should be more complex, but not that much.
> 2.  Get it running on Win32 & WinCE..  (blech ?? blech blech ?? :-) )
>
>   
No scale here. I really have no idea. I don't know if llvm has jit 
support for win32. If it's the case then this is what one should do:

1) Verify that pthreads and mmap work (does cygwin have them?). I think 
these are the only two system dependent parts of vmkit. Maybe dlopen too?
2) Implement a different exception scheme: IIRC, C++ exceptions are 
managed differently in windows. Since vmkit relies on dwarf and the 
dwarf tables emitted bi LLVM's JIT, the whole thing has to be rewritten.
> Thanks again.
>
> Your project looks great!!!
>
>   
Thanks!
Nicolas

> -tim
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