Initial psymtab replacement results

[Tom Tromey]

>>>>> "Tom" == Tom Tromey <tromey@redhat.com> writes:

Tom> Actually, I finished it yesterday and got preliminary results:
[...]

This week I fixed a few bugs and tried this out on OO.o.

The attach results are competitive with the .debug_gnu_index approach --
actually a bit faster, as one would expect, because less work is done at
startup.

"thread apply all bt full" is a little slower (than .debug_gnu_index), I
think because this code uses a "pre-expand" model, and is fairly
indiscriminate.  That is, if a given symbol (say a type name) is looked
for, all symtabs holding that name are expanded.  The slowdown isn't
severe, though, but it could be fixed by some additional smarts in the
index writer.

This version of the index code is faster than CVS gdb on both operations
(when the index exists).

Tom