Using g++ to build java?

Using g++ to build java?

[Kaveh R. Ghazi]

So, did we come to a conclusion about whether to use C++ in Java and
how to accomplish it while bootstrapping?  IMHO, the easiest solution
is to arrange to compile g++ during stage1 so we are free to use it in
stage2 and later for building other languages.

Since we can rely on ISO C now, our first step is to get rid of gcc
extensions in the g++ frontend.  To achieve this and to ensure it
remains so, it means we have to build cc1plus with -pedantic and
squelch any problems.

I tried it and got these warnings:

 > % .../contrib/warn_summary -cp output.log
 > Counting warnings in the gcc/cp subdirectory,
 > there are 1014 warnings in stage3 of this bootstrap.
 > 
 > [...]
 > 
 > Number of warning types:
 >  713 ISO C forbids braced-groups within expressions
 >  216 bit-field `???' type invalid in ISO C
 >   55 comma at end of enumerator list
 >   11 ISO C forbids use of conditional expressions as lvalues
 >    8 ??? format, ??? arg (arg ???)
 >    7 `return' with a value, in function returning void
 >    4 ISO C does not allow extra `???' outside of a function

These all look like simple (i.e. obvious one-line) fixes.  The high
number results from headers repeatedly included.  I.e. we don't
actually have to fix 1000 spots. :-)

Are there any objections to proceeding?  If we're concerned about
diverging from 3.3 and creating merge conflicts, I believe all of
these changes will be so simple that we could safely put them in both
mainline and branch.  I.e. we're talking about e.g. adding
`__extension__' or removing extra commas, etc.

Once we get these fixed, I can test building cc1plus using solaris2
and irix6 cc to ensure it works with ISO C compilers.

		--Kaveh
--
Kaveh R. Ghazi			ghazi@caip.rutgers.edu

Re: Using g++ to build java?

[Tom Tromey]

>>>>> "Kaveh" == Kaveh R Ghazi <ghazi@caip.rutgers.edu> writes:

Kaveh> So, did we come to a conclusion about whether to use C++ in Java and
Kaveh> how to accomplish it while bootstrapping?

Kaveh> Are there any objections to proceeding?  If we're concerned about
Kaveh> diverging from 3.3 and creating merge conflicts, I believe all of
Kaveh> these changes will be so simple that we could safely put them in both
Kaveh> mainline and branch.

FWIW, I haven't been able to find the time to work on merging the
libgcj verifier back into gcj.  This certainly won't happen for 3.3.
So perhaps the divergence isn't an issue.

Tom

Re: Using g++ to build java?

[Kaveh R. Ghazi]

 > From: Tom Tromey <tromey@redhat.com>
 > 
 > >>>>> "Kaveh" == Kaveh R Ghazi <ghazi@caip.rutgers.edu> writes:
 > 
 > Kaveh> So, did we come to a conclusion about whether to use C++ in Java and
 > Kaveh> how to accomplish it while bootstrapping?
 > 
 > Kaveh> Are there any objections to proceeding?  If we're concerned about
 > Kaveh> diverging from 3.3 and creating merge conflicts, I believe all of
 > Kaveh> these changes will be so simple that we could safely put them in both
 > Kaveh> mainline and branch.
 > 
 > FWIW, I haven't been able to find the time to work on merging the
 > libgcj verifier back into gcj.  This certainly won't happen for 3.3.
 > So perhaps the divergence isn't an issue.
 > Tom

Divergence (between mainline and 3.3 cc1plus) would be an issue if I
worked on it now in preparation for your future effort.

Being bored, I went ahead and fixed all of the cc1plus -pedantic
warnings except for one type (which turned out to require some extra
poking to fix.)

I'll submit them in a little while.

		--Kaveh
--
Kaveh R. Ghazi			ghazi@caip.rutgers.edu