Seeing this [1], I thought it was something related to taking assembly instructions in the original code, emitting C statements that match the instruction, and then compiling that C code.

[1] https://github.com/N64Recomp/N64Recomp

Your idea is much more accurate; see my sibling comment. It's basically using C or C++ as an intermediate representation for machine code, rather than trying to recreate the game's higher-order logic/structure or source code.