[llvm] [LLVM][DWARF] Add compilation directory and dwo name to TU in dwo section (PR #74909)

[David Blaikie via llvm-commits]

dwblaikie wrote:

Looks OK.

We could potentially do this in all DWARF versions, not just >= 5. (seems relatively harmless to do it in the v4 extension version of Split DWARF?)

& could you get some measurements, especially .o file size (or more specifically, .o .debug_info size) for a clang build with this patch/without this patch? Just so we know what sort of growth to expect.

https://github.com/llvm/llvm-project/pull/74909