/usr/lib/x86_64-linux-gnu/libLLVM-3.8.0.so.1 is in llvm-3.8-dev 1:3.8-2ubuntu1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libLLVM-3.8.so.1
/usr/lib/x86_64-linux-gnu/libLLVM-3.8.so.1