Re: [rfa/dwarf] Support for attributes pointing to a different CU

[Jim Blandy <jimb at redhat dot com>]

I take it the reason we can't just fill in all the per_cu->psymtab
values when we build the psymtabs in the first place is that we don't
actually build the CU index until we see a CU that contains (or might
contain) inter-CU references.  So we'd have to go back and record the
psymtabs we'd already created anyway.  Is that right?

We're constructing a psymtab for every CU we see; does it save much
time or space to avoid creating a twenty-byte structure as well?  I
understand that this is time- and space-critical code, but if the hair
isn't a noticable win, I'd rather it not go in.