[gentoo-java] work on gcj for gentoo

[Hanno Meyer-Thurow <h.mth@web.de>]

Hi list!
I would like to work on gcj for Gentoo.
I spoke with Andrew Cowie. He suggested me to send my ideas and
questions to this list to discuss.

I know gcj is tricky. It has various issues. Still, it is quite interesting
to work on gcj. But as gcj is in portage right now it is hard to use for
an ebuild writer like myself. Just two main issues:

	* dependency tracking
	* JDK-like environment

However, I may write my ideas and questions:

I thought in a gcj-4.1 / ecj combination. Use ecj to bytecompile Java
source to jar with gcj as backend. Then use gcj to create native
executables or libraries out of that jar files. Creating a database
via gcj-dbtool for jar / native code resolution. If possible Java to
native.

The steps to take to get there

	* get gcj-jdk in portage
	* use ecj as gcjs bytecompiler
	* handle it via Gentoos java config
	  (gcj bytecompile is broken,
	  see http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18131)

(later)

	* Java to native compilation
	* utilize gcj-dbtool for jar / native code resolution
	  (Whatever way it is wanted.)

To stay sane we want to hack the ant-core dependency out of
eclipse-ecj package. Just try to compile ant-core with gcj. I have
ugly hacks (gcc PR19870) for ant-core-1.6.2 to bytecompile with gcj.

	No way.

Then I have to get ant-core-1.6.5 to bytecompile with gcj / ecj which
fails right now - did not yet investigate any further. After these steps
are done we have the base (for interested ones to test gcj).

	I am no Java programmer.
	I do packaging stuff and ugly hacking. ;)

I will try to integrate gcj into Gentoos next Java config utility.
Just not to do the work of integration twice.

What I did already:

	* tweaked Andrew's gcj-jdk ebuild
	-> ebuild / eclass split
	* gcj-ecj ebuild
	-> Java to native: ecj binary

The very next steps should be:

	* better gcj-jdk ebuild
	* fix ant-core issue with ecj

Then, get back to plan.

Reference - my overlay for these two ebuilds:
http://geki.ath.cx/hacks/gcj-overlay-2.tar.bz2


Thanks in advance for help!


Regards,
Hanno
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