Use function_ref here instead.
This looks like something that should be computed during initialization.
The = nullptr is unnecessary.
Address River's comments.
I tried it before, but then the command-line options won't work.
You can either override initialize or override initializeOptions and do it there.
addressed in https://github.com/llvm/llvm-project/commit/891e769ab68f2cdbd105cb42f5c2f40051c70837