Re: Ada platforms and pricing, was: Re: a new language, designed for safety !

[Brian Drummond <brian3@shapes.demon.co.uk>]

On Wed, 18 Jun 2014 12:32:57 +0200, J-P. Rosen wrote:

> Le 18/06/2014 09:09, Natasha Kerensikova a écrit :
>> Anyway, I'm willing to contribute a lot of my free time to help a new
>> free Ada compiler emerge, ideally a LLVM front-end written from scratch
>> in Ada, bootstrapped by FSF GNAT, licenced under BSD or Apache or
>> something like that.
> 
> You may not have to start from scratch. Pick-up the Gela-ASIS project
> (currently sleeping) and fix what's missing. That will give you a
> stand-alone implementation of ASIS, that could be used to generate code
> from.
> 
> You may even find people at your working place to help you in such an
> endeavour ;-)

Also possibly worth looking at ghdl. It's not an Ada compiler, but a 
compiler, written in Ada, for a somewhat related language (VHDL). 

http://sourceforge.net/projects/ghdl-updates/
(disclaimer : I do a little - lately VERY little - on this project)

Its author Tristan Gingold is now employed by Adacore so probably can't 
help a rival effort!

Ghdl separates the front end and back end quite cleanly, with an 
intermediate representation ("ortho") which currently interfaces to any 
of: 
gcc, 
its own JIT compiler for i386
and recently, LLVM.

LLVM caused some trouble; apparently it does not provide means to support 
nested (locally declared) subprograms, such as the chain of frame 
pointers (or alternatively display) to access the scope of outer 
subprograms. This may have been a stumbling block for other Ada/LLVM 
projects.

Because VHDL supports multiple processes, ghdl leverages the support for 
these, to provide the chain of scopes. So one option may be to use part 
of this project as an adapter between Gela/Asis and LLVM.

- Brian