[llvm] [DwarfDump] Add new set of line-table-related statistics to llvm-dwarfdump (PR #93289)

[J. Ryan Stinnett via llvm-commits]

jryans wrote:

> My assumption at the moment would be that this is passed through as JSON, s.t. new fields will be ignored by default - so it shouldn't cause any problems at least for the existing stats, though it would be good to get these added!

Ah yeah, I don't think it will cause problems either, I was more just thinking about ensuring the new fields are tracked over time going forward. But yeah, IIUC, there's no rush to do anything immediately after merging this because of the JSON structure as you mentioned.

> Without getting ahead of things too much (I'll have a discourse post soon going more into the topic), it looks as though the unique lines metric has been degrading in clang over time, so it'd be good to get some continuous measurement.

Ah, good to know. Would be great to have more people watching those stats as they evolve... I might be one such person soon, we'll see. 😄 

https://github.com/llvm/llvm-project/pull/93289