Comment by bri3d

JIT isn't _that_ common in games (although it is certainly present in some, even from the PS2 era), but self-modifying or even self-referencing executables were a quite common memory saving trick that lingered into the PS2 era - binaries that would swap different parts in and out of disk were quite common, and some developers kept using really old school space-saving tricks like reusing partial functions as code gadgets, although this was dying out by the PS2 era.

Emulation actually got easier after around the PS2 era because hardware got a little closer to commodity and console makers realized they would need to emulate their own consoles in the future and banned things like self-modifying code as policy (AFAIK, the PowerPC code segment on both PS3 and Xbox 360 is mapped read only; although I think SPE code could technically self-modify I'm not sure this was widespread)

The fundamental challenges in this style of recompilation are mostly offset jump tables and virtual dispatch / function pointer passing; this is usually handled with some kind of static analysis fixup pass to deal with jump tables and some kind of function boundary detection + symbol table to deal with virtual dispatch.