• Gregor Richards <Richards codu.org> Dec 12 2006
• =?ISO-8859-1?Q?Anders_F_Bj=F6rklund?= <afb algonet.se> Dec 13 2006
• Gregor Richards <Richards codu.org> Dec 13 2006
• =?ISO-8859-1?Q?Anders_F_Bj=F6rklund?= <afb algonet.se> Dec 13 2006
• Lars Ivar Igesund <larsivar igesund.net> Dec 13 2006
• Alexander Panek <a.panek brainsware.org> Dec 13 2006
• Gregor Richards <Richards codu.org> Dec 13 2006
• Lars Ivar Igesund <larsivar igesund.net> Dec 13 2006
• Gregor Richards <Richards codu.org> Dec 13 2006

No, I'm not saying somebody should do it, I'm saying I've done it.

http://www.codu.org/nestedvm-gdc/

Using NestedVM, a tool that lets you compile anything GCC supports to 
Java bytecode, I've made a modified copy of GDC that can produce native 
Java .class files from D source.

What's the use? I don't know, I only did it to have a bit of perverse fun.

Sockets and threads don't work yet, and it's not extensively tested, but 
it works enough to get a simple Hello, World! compiled.

I'll put up full documentation on using it later, just thought the NG 
might be interested in knowing it exists.

  - Gregor Richards

Gregor Richards wrote:

 Using NestedVM, a tool that lets you compile anything GCC supports to 
 Java bytecode, I've made a modified copy of GDC that can produce native 
 Java .class files from D source.
 
 What's the use? I don't know, I only did it to have a bit of perverse fun.
 Sockets and threads don't work yet, and it's not extensively tested,
 but it works enough to get a simple Hello, World! compiled.


Excellent hack! Will give it a try on Mac OS X, might even be useful. :)

"NestedVM provides binary translation for Java Bytecode. This is done by 
having GCC compile to a MIPS binary which is then translated to a Java 
class file."

"Entire virtual memory space mapped to a giant int[][] array indexed by 
page, then address. Breaking memory up by pages allows memory to be 
dynamically allocated."

"Applications interact with the Operating System via the SYSCALL 
instruction. ... The syscall instruction is simply mapped to
the syscall() method of the Runtime class."

So it seems the only thing GDC needs is a "nestedvm" OS and "MIPS" CPU ?

--anders

PS. Quotes from http://www.zentus.com/nestedvm/ and their NestedVM.pdf

Anders F Björklund wrote:
 Gregor Richards wrote:
 
 Using NestedVM, a tool that lets you compile anything GCC supports to 
 Java bytecode, I've made a modified copy of GDC that can produce 
 native Java .class files from D source.

 What's the use? I don't know, I only did it to have a bit of perverse 
 fun.
 Sockets and threads don't work yet, and it's not extensively tested,
 but it works enough to get a simple Hello, World! compiled.


 Excellent hack! Will give it a try on Mac OS X, might even be useful. :)
 
 "NestedVM provides binary translation for Java Bytecode. This is done by 
 having GCC compile to a MIPS binary which is then translated to a Java 
 class file."
 
 "Entire virtual memory space mapped to a giant int[][] array indexed by 
 page, then address. Breaking memory up by pages allows memory to be 
 dynamically allocated."
 
 "Applications interact with the Operating System via the SYSCALL 
 instruction. ... The syscall instruction is simply mapped to
 the syscall() method of the Runtime class."
 
 So it seems the only thing GDC needs is a "nestedvm" OS and "MIPS" CPU ?
 
 --anders
 
 PS. Quotes from http://www.zentus.com/nestedvm/ and their NestedVM.pdf


First off, for the skeptical: While all those quotes are true, it isn't 
as bad as it seems. It compiles the actual code to Java bytecodes, so 
it's not a virtual /execution/ environment, just virtual memory and a 
virtual syscall handler.

OK, now on to what you actually asked:

I'll be documenting how to get it all compiled soon. It's unfortunately 
a bit of a pain in the arse. Basically, you need to compile NestedVM 
(with GCC <4), then compile a newer GCC with GDC and my patch, with the 
same configure flags as those used for NestedVM.

G'luck if you want to try it before I put up a doc :)

  - Gregor Richards

Gregor Richards wrote:

 PS. Quotes from http://www.zentus.com/nestedvm/ and their NestedVM.pdf


 First off, for the skeptical: While all those quotes are true, it isn't 
 as bad as it seems. It compiles the actual code to Java bytecodes, so 
 it's not a virtual /execution/ environment, just virtual memory and a 
 virtual syscall handler.


I actually thought "was that all there was to it" and that it sounded 
easy, sorry if it sounded bad in any way. Patches to GDC were minimal*.

I thought the virtual execution environment of the JVM was a feature :-)
Somehow the idea of running a virtual OS in a virtual VM is hilarious.

Running through your installation, just installing darcs and ghc first.
(not sure if it's needed but seemed to be, so I use MacPorts to install)

--anders

* it probably could be cut down a bit, once the autoconf stuff is fixed.

Gregor Richards wrote:

 No, I'm not saying somebody should do it, I'm saying I've done it.
 
 http://www.codu.org/nestedvm-gdc/
 
 Using NestedVM, a tool that lets you compile anything GCC supports to
 Java bytecode, I've made a modified copy of GDC that can produce native
 Java .class files from D source.
 
 What's the use? I don't know, I only did it to have a bit of perverse fun.
 
 Sockets and threads don't work yet, and it's not extensively tested, but
 it works enough to get a simple Hello, World! compiled.
 
 I'll put up full documentation on using it later, just thought the NG
 might be interested in knowing it exists.
 
   - Gregor Richards


I suppose the most important question would be how to interface between Java
and D.

-- 
Lars Ivar Igesund
blog at http://larsivi.net
DSource & #D: larsivi

What the... X_X

You seem to be pretty much bored, don't ya? :O

Apart from that, good work. Should be an argument against people 
shouting out loud about D not being capable of running inside a VM. ;)

Kind regards,
Alex

Alexander Panek wrote:
 What the... X_X
 
 You seem to be pretty much bored, don't ya? :O
 
 Apart from that, good work. Should be an argument against people 
 shouting out loud about D not being capable of running inside a VM. ;)
 
 Kind regards,
 Alex


Bored? Nah, I just have a perverse sense of humor ;)
It actually only took me a few hours to get this working.

That's a good point - it may not be particularly useful, but for people 
in love with VMs ... who knows.

  - Gregor Richards

Gregor Richards wrote:

 Alexander Panek wrote:
 What the... X_X
 
 You seem to be pretty much bored, don't ya? :O
 
 Apart from that, good work. Should be an argument against people
 shouting out loud about D not being capable of running inside a VM. ;)
 
 Kind regards,
 Alex


 Bored? Nah, I just have a perverse sense of humor ;)
 It actually only took me a few hours to get this working.
 
 That's a good point - it may not be particularly useful, but for people
 in love with VMs ... who knows.
 
   - Gregor Richards


Or who are otherwise contracted to use Java/JVM at work ... 

-- 
Lars Ivar Igesund
blog at http://larsivi.net
DSource & #D: larsivi

Gregor Richards wrote:
 No, I'm not saying somebody should do it, I'm saying I've done it.
 
 http://www.codu.org/nestedvm-gdc/
 
 Using NestedVM, a tool that lets you compile anything GCC supports to 
 Java bytecode, I've made a modified copy of GDC that can produce native 
 Java .class files from D source.
 
 What's the use? I don't know, I only did it to have a bit of perverse fun.
 
 Sockets and threads don't work yet, and it's not extensively tested, but 
 it works enough to get a simple Hello, World! compiled.
 
 I'll put up full documentation on using it later, just thought the NG 
 might be interested in knowing it exists.
 
  - Gregor Richards


I've added some basic documentation on compiling and installing 
nestedvm-gdc, as well as a nifty script 'gdcj' that does compilation and 
generation of .jar files for you :)

http://www.codu.org/nestedvm-gdc/

  - Gregor Richards