/usr/lib/x86_64-linux-gnu/libLLVM-3.1.so is in llvm-3.1-dev 3.1-2ubuntu1~12.04.1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libLLVM-3.1.so.1
/usr/lib/x86_64-linux-gnu/libLLVM-3.1.so.1