I imagine plenty of compilers do call free, but here's a 2013 article by Walter Bright on modifying the dmd compiler to never free, and to use a simple pointer-bump allocator (rather than a proper malloc) resulting in a tremendous improvement in performance. [0] (I can't speak to how many layers dmd has, or had at the time.)

The never-free pattern isn't just for compilers of course, it's also been used in missile-guidance code.

[0] https://web.archive.org/web/20190126213344/https://www.drdob...