Question/proposal for USE_MAPPED_LOCATION and Ada

[Robert Dewar]

Steven Bosscher wrote:

> I don't think having your own location representation is a waste of
> space and time.  Zack likes clean, I'm more pragmatic: It's a design
> decision.

One thing to be aware of in the Ada case is the requirement for
properly tracking the distinction between a generic template and
its instantiations, to all depths of instantiation. In the GNAT
front end, a 32-bit source location is sufficient to record both
the source location in the generic template and the source location
of all instantiations. This is quite important for getting good
error message placement. Source location here = line/column.
> 
> In the Fortran case, the question is:  Does GCC provide adequate
> language independent diagnostics machinery? (A: apparently yes, and
> with a little luck we'll even get column information back!).
> In your case, the question is: Do you want our front end to depend on
> linemap.[ch] outside gigi?  If not, then implement your own location
> representation, translate your representation to that of GCC, accept
> the space and time penalty, and be done with it.

It's probably not that big a penalty I would guess, though, as above,
I would guess this is a "lossy" translation, and that the gcc messages
won't know about instantiations.