[clang] [llvm] Add support for Windows hot-patching (PR #138972)

[via cfe-commits]

MolecularMatters wrote:

> This is very interesting!
> 
> Initially I also assumed this was about Edit&Continue. As users may have the same idea, I'd suggest adding `DocBrief`s to the new Clang options, and a comment at the top of llvm/lib/CodeGen/WindowsHotPatch.cpp that explain in more detail what they do.

Seconded.
I'd even vote for renaming the command-line options entirely.

We already have `/HOTPATCH` or rather `-fms-hotpatch` that does something different, so `-fms-hotpatch-functions-file` and `-fms-hotpatch-functions-list` might be confusing, because they don't have anything to do with `-fms-hotpatch` at all.

https://github.com/llvm/llvm-project/pull/138972