refactor(tvix/eval): add name-based index over compiler's locals r/5454

Instead of finding locals by doing 2x O(n) walks over the compiler's
locals list, use a secondary name-based index for resolving locals by
name.

Previously, almost 60% (!!) of eval time on some expressions over
nixpkgs was spent in `Local::has_name`. This function doesn't even
exist anymore now, and eval speed about doubles as a result.

Note that this doesn't exactly make the locals code easier to read,
but I'm also not sure what we can simplify in there in general.

This fixes b/227.

Change-Id: I29ce5eb9452b02d3b358c673e1f5cf8082e2fef9
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7560
Reviewed-by: grfn <grfn@gws.fyi>
Tested-by: BuildkiteCI

0 files changed, 0 insertions, 0 deletions