[llvm] [llvm-c] Add LLVMParseIRInContext2 (PR #174085)

[Alan Hu via llvm-commits]

https://github.com/alan-j-hu approved this pull request.

One qualm that I have is over defining `protect` twice, in both the bitreader.ml and irreader.ml test programs. The most logical place to define `protect` could be in `Utils/Testsuite.ml`. However, this would mean that bitreader.ml and irreader.ml would have to be compiled with this file (currently, only the core.ml test program pulls it in). Considering that `protect` is only a temporary definition until the minimum OCaml version has this function in its standard library, I am okay with defining it twice for now.

Come to think of it, what is the policy for bumping the minimum version of OCaml? Right now, the README file in bindings/ocaml states the minimum version required is OCaml 4.00. In particular, if `protect` is used in the tests, using it would not impact the minimum version required for end users.

https://github.com/llvm/llvm-project/pull/174085