/usr/lib/ocaml/llvm-3.3/libLLVMX86Disassembler.a is in libllvm-3.3-ocaml-dev 1:3.3-16ubuntu1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/ocaml/llvm-3.3/../../llvm-3.3/lib/libLLVMX86Disassembler.a