/usr/lib/gcc-cross/mips64-linux-gnuabi64/7/plugin/libcp1plugin.so is in gcc-7-mips64-linux-gnuabi64 7.3.0-16ubuntu3cross1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/gcc-cross/mips64-linux-gnuabi64/7/plugin/libcp1plugin.so.0.0.0