/usr/lib/llvm-3.5/lib/libLLVM-3.5.2.so.1 is in llvm-3.5-dev 1:3.5.2-3ubuntu1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/llvm-3.5/lib/../../x86_64-linux-gnu/libLLVM-3.5.so.1
/usr/lib/llvm-3.5/lib/../../x86_64-linux-gnu/libLLVM-3.5.so.1