Re: Implementing an Ada compiler and libraries.

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

On May 9, 5:51 pm, "Dmitry A. Kazakov" <mail...@dmitry-kazakov.de>
wrote:
> > But I'm interested in seeing how I can get the compiler to not have to
> > reparse other source files (when with'd) in order to compile a unit.
>
> Why should it? Certainly, you would have some intermediate representation
> which includes symbolic tables and other stuff the compiler creates after
> semantic analysis before code generation. A compiled library unit will have
> this stored in some appropriate format.

True, but is it possible to include dependency info within the object
itself?

> 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.

> > Also, I'd like to see how static/shared libraries can be implemented/
> > used to extend the Ada standard library.
>
> I don't think it is a good idea to mix Ada libraries and
> object/dynamic-linking libraries, at least in existing OS'es. In some OO OS
> with advanced containers it could work. But still, these are two different
> abstraction levels. Object code is too close to the hardware. The library
> units should probably be kept on the other side.

Why? Are you saying that it would be better to store libraries in IR
rather than binary form? For a linux based compiler (for example) you
still need to be able to link with binary libs, and I do think it's
necessary to be able to build a shared lib with an Ada compiler - this
would not be possible with IR, unless the whole OS worked in this way.

> > I don't want to have to have
> > tons of source files lying around for a static/shared library, I
> > honestly don't see the need. Surely, it's possible to build a compiler
> > that can get the information it needs from the library itself (or at
> > least a companion library rather than a ton of different ALI files)?
>
> Or a database, for that matter...

Like the old Ada library? 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.

> > Now, I'd really like to hear from people who have implemented an Ada
> > compiler and people who have used other compilers (I've only used
> > GNAT). Basically, I'm interested in how other implementations handle
> > the library. Note that there are 2 ideas of library here:
>
> > 1) The standard Ada library.
> > 2) Link/shared libraries found on operating systems.
>
> 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?

Thanks,
Luke.