/usr/lib/x86_64-linux-gnu/libLLVM-3.4.so is in llvm-3.4-dev 1:3.4-1ubuntu3.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libLLVM-3.4.so.1
/usr/lib/x86_64-linux-gnu/libLLVM-3.4.so.1