[llvm] Introduce CovMap in ObjectYAML (PR #127432)

[James Henderson via llvm-commits]

https://github.com/jh7370 commented:

There's an awful lot of code in this PR now and I wouldn't be confident in anybody's ability to reliably review it all at once. Is there a way you could split it down into multiple pieces?

For example, could you have support for each relevant section in a separate PR, or are there parts of the section format that are not required to have a "minimal" section that can be generated. You could even have the section not technically correct, but have some of the fields or similar not emitted initially, even though they're required for the proper behaviour. This allows for reviewing to focus on individual bits at a time. Keeping this PR as-is would still be useful, in that it could act as a reference point so that reviewers can look at the "big picture" too.

https://github.com/llvm/llvm-project/pull/127432