/usr/bin/sancov-4.0 is in clang-tools-4.0 1:4.0.1-10~deb9u2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/bin/../lib/llvm-4.0/bin/sancov
/usr/bin/../lib/llvm-4.0/bin/sancov