A lot of this bootstrapping stuff comes back to the ‘trusting trust’ attack. You could write a compiler that adds some malicious code to programs it compiles. But the thing is, it could also insert it’s own malicious code when compiling a compiler. So you look at your code, and the code of your compiler, and everything looks fine, but the exploit is still there. Someone wrote an example in rust.

Theoretically there could also be bugs that propagate this way. So to fully trust your code is doing what you think it is, you’d need a chain of compilers back to hand coded assembly.

The main thing is that TinyCC has already been bootstrapped.

Check out this page on bootstrappable.org. Basically they start with a 200 something byte binary (hex0) that can act as an assembler, then using a bunch of layers of tools and compilers you can bootstrap a whole system. I think they use stage0 to build M2-Planet, use that to build GNU Mes, and use that to build TinyCC.

So a project like this fits neatly into that bootstrapping path. It could be done other ways, but starting from a fairly complete C compiler makes it a lot easier than building an entire path from scratch.

You can technically do it, but it’s a convoluted path. The article talks about it. Basically to bootstrap that way you need to go through a lot of versions of rust, compile rust 0.7 in ocaml, compile ocaml in scheme, and compile scheme in C using gcc. For gcc you need to compile a chain of versions back to when it was written in C instead of C++, plus the whole TinyCC bootstrapping path.

edit: had listed scala instead of ocaml