I built a C compiler that runs on a Raspberry Pi Pico ($4, 264KB RAM). It compiles C to ARM Thumb and JIT-executes it.

It can compile its own source code on the hardware.

Full pipeline: preprocessor, parser, type system, Thumb-1/Thumb-2 codegen, mark-and-compact GC, USB REPL.

Try it: flash the UF2, connect serial (115200), type "help".

https://github.com/ezulabs/MicroCC