What to do with MAPPED_LOCATION

[Per Bothner]

Robert Dewar wrote:
> Right, so it seems quite appropriate to have two representations for
> source locations, one for the Ada tree, which is completely independent
> of the tree IL, and one for the back end. That probably means that back
> end messages will lose the generic instantiation information, but that's
> not terrible.

First, the mapped source_location values can encode nested context.
This is used for the C/C++ include file context.  I think it is quite
possible to use the same mechanism for generic instantiation
information.

Second, the backend *currently* has no support for "generic
instantiation information" so I really don't understand your
point about "losing" this information.  You *might* lose it
if you switch to using source_location in the front-end (but
see my first point), as I've argued for in the past, but if
you're translating internal source location to back-end
representation at tree conversion time, which seems to be
your preference, then I don't understand your point.
-- 
	--Per Bothner
per@bothner.com   http://per.bothner.com/