Re: [gnat] reuse of ASTs already constructed

[Geert Bosch <bosch at adacore dot com>]

On Apr 12, 2009, at 13:29, Oliver Kellogg wrote:

> On Tue, 4 Mar 2003, Geert Bosch <bosch at gnat dot com> wrote:
> > [...]
> > Best would be to first post a design overview,
> > before doing a lot of work in order to prevent spending time
> > on implementing something that may turn out to have fundamental
> > problems.
>
> I've done a little experimenting to get a feel for this.
>
> I've looked at the work done toward the GCC compile server but
> decided that I want to concentrate on GNAT trees (whereas the
> compile server targets the GNU trees.)
>
> Also I am aiming somewhat lower - not making a separate compile
> server process but rather extending gnat1 to handle multiple
> files in a single invocation.

While this may be an interesting idea, there are some fundamental  
assumptions
in the compiler that each compilation indeed processes a single  
compilation unit,
resulting in a single object and .ali file. It would be best to first  
contemplate
what output a single invocation of the compiler, with multiple  
compilation units
as arguments, should produce.

How would you decide if a unit needs recompilation if there was no 1:1
correspondence between compilation units and object/.ali files?
Note that unlike many other languages, Ada requires checks to avoid
including out-of-date compilation results in a program.

  -Geert