Fix pretty printers to work with the broader enum optimizations

[cactorium]

As per #20405. To be more precise, the changes just the processing of enums when the name is "RUST$ENCODED$ENUM$..." so it correctly parses when there is more than one number encoding the location of the field it's looking for to determine state of the enum

[rust-highfive]

Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @nikomatsakis (or someone else) soon.

If any changes to this PR are deemed necessary, please add them as extra commits. This ensures that the reviewer can see what has changed since they last reviewed the code. The way Github handles out-of-date commits, this should also make it reasonably obvious what issues have or haven't been addressed. Large or tricky changes may require several passes of review and changes.

Please see CONTRIBUTING.md for more information.

[huonw]

r? @michaelwoerister

[michaelwoerister]

This looks very good to me at a first glance. Thanks for fixing those bugs!
Could you extend src/test/debuginfo/gdb-pretty-struct-and-enums.rs with a one or two test cases for this?

[cactorium]

No problem, and done!

[michaelwoerister]

Did you also run them? Because I'm pretty sure they should fail in the current form due to the wrong numbers in the gdb-check lines (should be $17 and $18). You can easily run them with make check-stage1-debuginfo-gdb.

[cactorium]

Ah, my bad, I assumed that they were run manually since I couldn't figure out how testing could work off of comments. Tested and fixed!

[michaelwoerister]

Looks great now, thanks a lot!