Java front-end and library patches v2

Java front-end and library patches v2

[Max Downey Twiss]

Disclaimer: this does not currently work.

The front-end and library compile successfully, but fail to link at
the very end.
This is due to a regression caused by
1dedc12d186a110854537e1279b4e6c29f2df35a, which I have been unable to solve.

Nevertheless, I am posting this patch series for two reasons.

Firstly, to get feedback and reviews on the 56 already existing
patches, even though most are just re-adding code or making idiomatic
changes, so that when the final issue is solved everything has already
been approved (hopefully) and the merge is good to go.

Secondly, to get assistance with the final issue, because it is simply
beyond me, and history has shown that asking for help via gcc-patches
will yield nothing.

You'll need libtool 2.4.7 and a bleeding-edge version of bdwgc to
build it, in case anyone planned to do some testing.

Answers to the questions asked on my last patch series leading email:

> Why is it now considered useful to add this front end back?

The way I see it, the Java front end was removed due to a lack of
maintenance and improvement. To put it simply, I am going to maintain
and improve it. That is the difference between now and then. There is
more nuance, but that is the gist of it.

> Which version is the basis of the one being added back...?

The exact same one that was removed from GCC, with the version taken
being the one right before it was removed.

> Would you propose to maintain the front end and libraries in future?

I have big plans for the library, and plan to maintain that long into
the future. In regards to the actual front-end code, I will do what I
can to make sure it remains at its previous level of function, but
that is about it. I dislike working with the front end code, so I will
fix it, but I will not make sweeping changes to it.

>  Would you re-open any bugs against the front end or libraries that were closed...as a result of it being removed from the tree...?

Good point, I hadn't thought of that. It makes sense to re-open them,
as they are by definition valid again, although I may have difficulty
with the frontend ones, as that is not my strong suit.




Just a brief overview of my plans for the frontend and library-- When
GCJ was first introduced it was "the free Java implementation". It was
trying to offer a bytecode compiler, a machine code compiler and a
runtime library. Clearly, this was too much, as it borrowed another
bytecode compiler and runtime library, and even then the runtime
library fell into dissaray.

Now, we have many pieces of the puzzle. We have a bounty of free Java
bytecode compilers, and a free runtime library. The only thing missing
is a free machine code compiler, which GCJ was and is. I plan to
replace Classpath with the OpenJDK, and double down on the machine
code aspect of GCJ, dropping bytecode and interpreted support.

Re: Java front-end and library patches v2

[Max Downey Twiss]

The astute among you may have noticed that I in fact sent no patches.

This is for two reasons--

1. Google did something behind the scenes and broke git send-email for me again

2. Thanks to Iain Sandoe, the build now completes, and he provided a
couple other fixes as well. There are still a couple issues
post-build, though, and it makes more sense to work through those
before posting a v2.