Re: [RFA/dwarf] Optimize partial DIE reading for uninteresting DIEs

Jim Blandy
2004-02-27T02:58:38Z

Daniel Jacobowitz <drow@false.org> writes:
> You're mistaken about the expense. In particular read_unsigned_leb128
> is much slower than skip_uleb128 because of the computations to build
> the result; IIRC variable shifts are expensive. Yes, this was measured
> with an optimized build and a non-intrusive profiler. There's also the
> different memory access patterns.

No kidding. I'm amazed. Okay.

> Most of the speedup comes from not reading in the attribute values,
> though.

If what you say above is so, then two distinct versions of the
attribute traversal are clearly called for.

It would be interesting to compare profiling results between two GDB's
that differ only in whether they use your attribute skipper or the
attribute value reader.