[llvm] [LLVM][DWARF] Add support for .debug_names with split dwarf (PR #73872)

[Alexander Yermolovich via llvm-commits]

ayermolo wrote:

> Looks good to me.
> 
> The DWARF spec I think is a smidge vague on how the IDX_type_unit works with the local and foreign type units. (like if you had 5 local and 5 foreign type units (won't happen for us with object files, but would happen with the linked index) - presumably an IDX_type_unit value of 5 means the first foreign type unit? and 4 means the last local one?))
> 
> (also, total aside: be interesting to measure the size of `.debug_names` relative to `.debug_gnu_pubnames` and consider including a flag for producing `.debug_names` without the hash table in object files (if it's going to be merged into a unified index by the linker anyway, we don't need the hash table in the object file, probably))



> IDX_type_unit

Yes.
On page 138, section 6.1.12
"The foreign TU list immediately follows the local TU list and they both
34 use the same index, so that if there are N local TU entries, the index for the first
35 foreign TU is N."

https://github.com/llvm/llvm-project/pull/73872