High level code must be compilable to different run-time engines: PG; C; CL;
Different services and tools should be callable, e.g. code linter; SAT solvers;
This is related to paradigm/rich-runtime.
For every operation of a run-time should be possible figure-out or profile the cost, and then optimize it. For example in a DBMS run-time there are the query plans, the slow queries logs, and then one can add indexes and similar things.