/usr/lib/ocaml/llvm-2.9/libLLVMInterpreter.a is in libllvm-2.9-ocaml-dev 2.9+dfsg-3ubuntu4.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/ocaml/llvm-2.9/../../llvm-2.9/lib/libLLVMInterpreter.a