[llvm] [IR] Check that arguments of naked function are not used (PR #104757)

[Eli Friedman via llvm-commits]

https://github.com/efriedma-quic approved this pull request.

LGTM

Neither clang nor rustc allows referencing parameters in naked functions, and such usage is broken.  (See https://rust-lang.github.io/rfcs/2972-constrained-naked.html for rustc.)

clang's checking of naked functions is currently somewhat deficient in other respects; for example, clang allows arbitrary function calls in input parameters.  But that's a separate discussion.

https://github.com/llvm/llvm-project/pull/104757