[llvm] [MC] Fix DWARF file table for files with empty DWARF (#119020) (PR #119229)

[via llvm-commits]

zmodem wrote:

>  I _think_ DWARF is only supported from ELF and mach-o (darwin-derived platforms). but @rnk or @zmodem could clarify if I'm wrong.

DWARF is not normally used on Windows, but it _can_ be used (Clang can emit it, and I think it's not uncommon in MinGW builds maybe), and I believe LLDB can consume it on Windows.

Using MASM to generate DWARF does seem like a fringe use case though. I don't even know if there are flags to actually do so.

> The Masm discussion can continue/be addressed in a separate change if needed.

This sounds reasonable to me.

https://github.com/llvm/llvm-project/pull/119229