This replaces a few home-grown datastructures with third-party ones that
get a lot more testing:
- The home-grown hopscotch hash table is moved to using robin map. The
original was designed to be lock free, but we've been using it behind
a lock for ages.
- The selector list is now a std::vector.
- The types list now use std::forward_list.
This also removes a couple of code paths that haven't been used since we
started using the new ABI data structures internally and upgrading at
load time.
The new code tries to differentiate in the static type system between
registered and unregistered selectors. The check for whether a selector
is registered is fragile and depends on no selector being mapped or
allocated in memory below the total number of selectors. This check can
now disappear on most code paths.
On a single test machine (not guaranteed to be representative) the test
suite now completes around 20% faster.
The runtime was handling the message lookup correctly in this case, but only as a side-effect of the fallback code from when type-dependent dispatch is not possible. This resulted in a confusing warning message, telling you that you were calling a method with an incorrect signature, when the two signatures that it printed were the same.
This case is now handled correctly, so the warning disappears (unless you really are calling a method with the wrong signature and have TDD enabled).
Imported selector table code frm the Étoilé runtime. We can now make dispatch type dependent with a -D switch. Not enabled yet, but it will be enabled in a warning mode soon - I consider preferable to the existing GNU and Apple solution of corrupting the stack.