gij gcj-dbtool and questions

[Jakob Praher]

Am Montag, den 27.12.2004, 13:33 +0100 schrieb Jakob Praher:
> hi all,
> 
> after some research, I've resolved the problem with the gcj-dbtool.
> apparently the idea is that 
> 
> VMCompiler.compileClass( ClassLoader, String, ... )
> 
> does the mapping from jar file/bytecode to shared objects, and the class
> loaders are not aware of shared libs at all. 
> 
> This was my mistake, since the ClassLoader, namely VMClassLoader must be
> able to find a jar/class file that matches the requested class.
> Otherwise it throws the ClassNotFoundException and never calls the
> VMCompiler.compileClass method. (which happens in the defineClass of the
> VMClassLoader)
> 
> 
> BTW: In the end pnuts is still promlematic, but at least I've gained
> some insights how the gij/gcj-dbtool stuff works.

the pnuts compiler is working well. thanks to the fact that javacc has
no runtime dependencies and that the core doesn't need all that fancy
xml stuff.

wanted to say: kudos to you

-- Jakob

> 
> Am Donnerstag, den 23.12.2004, 00:16 +0100 schrieb Jakob Praher:
> > hi all,
> > 
> > i am using gcc-head with then new-abi stuff.
> > 
> > wanted to try to get started by using pnuts, a scripting language for
> > java to run with gij.
> > 
> > so i did the following:
> > 
> > gcj -findirect-dispatch -shared -o libpnuts.so pnuts.jar
> > gcj-dbtool -n pnuts.db
> > gcj-dbtool -a pnuts.jar libpnuts.so
> > 
> > gij -Dgnu.gcj.precompiled.db.path=./pnuts.db pnuts.tool.Main
> > 
> > prints:
> > 
> > Exception in thread "main" java.lang.NoClassDefFoundError:
> > pnuts.tools.Main
> >    at gnu.java.lang.MainThread.run()
> > (/home/jp/gcc-head/lib/libgcj.so.6.0.0)
> >    at _Jv_ThreadRun(java.lang.Thread)
> > (/home/jp/gcc-head/lib/libgcj.so.6.0.0)
> >    at _Jv_RunMain(java.lang.Class, byte const, int, byte const, boolean)
> > (/home/jp/gcc-head/lib/libgcj.so.6.0.0)
> >    at main (/home/jp/gcc-head/lib/libgij.so.0.0.0)
> >    at __libc_start_main (/lib/tls/i686/cmov/libc-2.3.2.so)
> > 
> > and doing a 
> > strace 2>&1 -e open gij -Dgnu.gcj.precompiled.db.path=./pnuts.db
> > pnuts.tool.Main | grep pnuts.db
> > 
> > yields that pnuts.db doesn't get loaded anyway - so how should it now
> > about the mapping ....
> > 
> > I found that the only file that uses the gnu.gcj.precompiled.db.path
> > property is java/lang/VMCompiler.java.
> > But I have to confess that I didn't look more into the details. I am
> > hoping to save some time and that you can give some details and status
> > information. 
> > 
> > BTW: Tom, I am interested in the gcjx stuff, your blog sounds pretty
> > interesting to me. When are you planing on integrating in as a
> > gcc-frontend... 
> > I am thinking about using relocation symbols and a more GOT/PLT like
> > approach for doing BC compatible linking, also with an application to
> > lazy procedure linking. I have invested pretty much time into the elf
> > dynamic linking approach, since I was very interested how it all worked.
> > I am currently writing a little documentation about that and have to
> > talk to one of my profs, perhaps I can do some sort of this as a diploma
> > thesis, which would be rather nice. The otable and atable stuff is
> > rather straightforwared to implement in pure elf, but the itable thing,
> > is a little bit more tricky, I suppose. After all that calls
> > _Jv_LookupInterfaceMethodIdx, which is a bit more tricky to implement as
> > elf sections.... 
> > Anyways I am providing more information on that, if you are interested.
> > 
> > Whishing you a mary chrismas, if that applies to you :-).
> > 
-- 
Jakob Praher <jpraher@yahoo.de>