In Lisp this might work like this (did and still does work in some commercial Lisp systems):

For example a Lisp system may consist of starting a memory image from disk, which leads to a live running memory heap. The tree shaker then may break unused links in memory - either automatic or under programmer direction. The garbage collector then frees the unused memory. Lisp then dumps a new (typically smaller) image, which has unused code and data removed.

Such features appeared no later than end 1980s.