[llvm] [DebugInfo] Add fast path for parsing DW_TAG_compile_unit abbrevs (PR #108757)

[Paul T Robinson via llvm-commits]

pogo59 wrote:

> Just out of curiosity, how common is the first abbreviation code not being 1 or code 1 not being DW_TAG_compile_unit? All C++/Swift/Rust programs I tested hit my fast path.

I don't have data, but things to try would be: enabling type units (a type unit might precede the compile unit); enabling split DWARF (would have a skeleton unit). I agree that a compilation without these features is pretty sure to have the CU show up first.

https://github.com/llvm/llvm-project/pull/108757