Re: Implementing an Ada compiler and libraries.

[Lucretia <lucretia9@lycos.co.uk>]

On May 10, 8:59 am, "Dmitry A. Kazakov" <mail...@dmitry-kazakov.de>
wrote:
> > True, but is it possible to include dependency info within the object
> > itself?
>
> Sure, it is just another "with". Each "with" loads (maps into the memory)
> the corresponding precompiled unit (compilation context). Some minor
> relocation stuff will be needed, checksums and time stamping as Gautier has
> mentioned. The symbolic tables (actually contexts) can be organized as a
> tree-stack to reduce loading overhead. "Use" plants a tree in the forest. I
> did such thing once. I guess it should make table look-ups slower. So the
> net effect on the compilation speed is unclear, before you actually build
> the thing.

True, have been thinking about this today. Don't know about the speed,
it'd have to be tested with enough of a subset and enough compilation
units.

> >> An interesting issue is cross-platform library units, I was playing with
> >> this idea, but came to no conclusion.
>
> > LLVM would be capable of this.
>
> Then is not a cross-platform, I mean the only platform here is the VM.
> Otherwise, it could be doable. Though many static things which are
> platform-dependent will cease to be compile-time static. So you will be
> unable to have certain things fully precompiled.

Well, no, the target is the VM, but it can be translated into any back-
end, thus portable to some degree.

> > Why? Are you saying that it would be better to store libraries in IR
> > rather than binary form?
>
> IR = infra red?

;D Intermediate Representation

> >> Or a database, for that matter...
>
> > Like the old Ada library?
>
> It wasn't that bad. DEC Ada had a library, if I correctly remember. With an
> integrated source control system it might become more attractive than the
> GNAT model. If I designed Ada tool-chain (the compiler is only a part of),
> I would probably choose this.

That's actually not a bad idea.

> > I was actually thinking, if I couldn't embed
> > the other information required by the compiler into the final object,
> > then a separate "lib" containing only this informaton would be
> > necessary.
>
> You mean symbolic info for the debugger?

No, I mean't the dependency information required by the compiler.

> >> I remember RSX-11 in which macro and object libraries were handled by the
> >> same librarian tool.
>
> > RSX-11 is before my time, got any more info on this?
>
> It was too primitive to be used for Ada. But the idea is basically same.

What idea? Same as what?

Thanks,
Luke.