alt Hacker NewsI’m not sure what I wrote to give the impression that Rust was unable to write a compiler, let alone implied it was impossible. Rust is certainly full featured enough to write a very well performing compiler. I find my comment more an indictment, and viewed uncharitably an accusation of hypocrisy, of the language org’s oversight that they are so heavily invested in LLVM (but if I was leveling such an accusation it would not be just because it’s a C++ project)
My comment was focused on the fact that Rust is not using a Rust compiler and therefore is relying on deep and complex C++ infrastructure while working to supplant the same at the lowest levels of the computing stack.
I was also commenting, up the thread, in a chain of comments about a perceived shortcoming of Rust’s implementation (i.e. it’s not being bootstrapped) and why some people view that as a negative.
Replies
All of the front-end is in fact pure Rust, I know that because I am one of the huge number of authors. The backend, thus the code generation and many optimisations of the sort AoCO is about is LLVM.
We absolutely know that if Rust didn't offer LLVM you'd see C++ people saying "Rust doesn't even have a proper optimiser". So now what you're asking for isn't just "a Rust backend" which exists as others have discussed, but a Rust alternative to LLVM, multiple targets, lots of high quality optimisations, etc. presumably as a drop-in or close approximation since today people have LLVM and are in production with the resulting code.
Doing a few things at a time is hardly an indictable offense. Self-compilation doesn't have to be anywhere near the start of the todo list. Relying on C++ infrastructure at compile time isn't a problem until you're trying to make all-purpose C++-free installs, and that's an entirely optional goal. The important part is having the runtime written in Rust.
Pointing out a language still needs C++ at compile time is a reasonable critique of "supplanting C++", but it's not a reasonable critique of "wanting to be a foundational language of the computing stack". Rust is the latter. (And even then it's too early to worry about compilers.) (And Rust is making good progress on compilers anyway.)