Re: Mixing Cygnus & Gnat compilers on the same machine

[Scott Ingram <scott@silver.jhuapl.edu>]

Marin David Condic wrote:
> 
> Well, the problem is that we already have a Cygnus compiler targeted to our
> MIPS machine - and not being the guy who handles that particular part of the
> deal I don't know if it is a "pure" MIPS thingie or if maybe there have been
> some customizations for our machine. (I'm pretty sure we already have a
> support contract with Cygnus on this.)

There are some weird and wonderful things that can be done with gcc. 
For example
it is relatively easy to have two or more versions of gcc in the same
tree.  (Examine
the "-V" option.)  Unfortunately, this is where the merge of the sources
becomes
important...the 2.9x versions of gcc are not Ada aware, so it makes no
sense to use
this particular feature.

I think customizations for your platform are unlikely (can't be ruled
out of course,)
but building a cross compiler for a supported platform is relatively
trivial.  As Stephe
notes, it does require following the directions very carefully.

Have you built gnat from sources?  I am certainly willing to help if you
need to.

> 
> No, I'm not in a position to fire Cygnus and hire ACT and I can't dictate
> that all new development be done in Ada. I was actually hoping for a
> "back-door" approach to it. If GNAT and the Gnu distribution of gcc get
> merged, there's some chance that the Ada front-end might at some point find
> its way into the Cygnus version that we are using. (Yes, I realize it won't
> happen by osmosis - I'm not totally dim! :-) Someone at Cygnus has to think
> this is worth doing.) That makes it possible for me to build some clever
> sideline things for the embedded computer in Ada. Suddenly, Ada becomes part
> of what we do and perhaps this causes some conversions to take place in the
> hearts and minds of other developers here. Its sneaky and underhanded, but
> often very effective!

When they get merged, the source will be available in your distribution
from
Cygnus.  Since you are using gcc, I presume that there is no requirement
for
a validated compiler to start with.  In that case it simply becomes a
matter
of rebuilding the compiler.  (Unless you are also using g++, which is
problematic
but not insurmountable.)  Unless there is some requirement for you to
NOT rebuild
the compiler...but then we run into a management issue that will have to
be
resolved somehow.

> 
> My observation here is that what I want to do isn't simply be able to
> generate code for a MIPS processor. Ada for MIPS has been available from a
> number of sources for some time. The problem is one of getting Ada
> introduced into an organization and that can require specific paths be
> taken.
> 

I think the issue here is "specific paths."  Technically there is no
difficulty
mixing the compilers, or even mixing objects generated by the current
versions...
perhaps you could elaborate?

> MDC
> --

-- 
Scott Ingram
Vice-Chair, Baltimore SIGAda
Sonar Processing and Analysis Laboratory
Johns Hopkins University Applied Physics Laboratory