crustc: entirety of `rustc`, translated to C

(github.com)

106 points | by Philpax 1 hour ago

13 comments

  • lioeters 59 minutes ago
    > For the past 3 years, I have been working on compiling Rust to C. .. This is, by my count, the 14th attempt: cilly

    Gotta respect the dedication to a niche interest.

    > The primary goal of this is support for old/obscure hardware with no LLVM/GCC support.

    I remember reading about the bootstrapping question, how it typically requires a Rust compiler to build the Rust compiler from source. https://bootstrapping.miraheze.org/wiki/Bootstrapping_Specif...

    Oh, but I see there's a C++ implementation of the Rust compiler. https://github.com/thepowersgang/mrustc

    Anyway, this part sounds useful too, that crustc can compile across network and devices.

    > You build a small C server on your Blorbo OS, run rustc on some normal platform like Linux, and let cilly talk over the wire.

    • zadikian 36 minutes ago
      So the author made a Rust to C transpiler and immediately used it to transpile... the Rust compiler. I love it.
  • taris2 59 minutes ago
    Have you tried Diverse Double-Compiling (DDC) to test if the official rust compiler has a backdoor?

    Use crustc to compile the rust source code, producing a new compiler. Then use this new compiler and the official rustc binary, both with deterministic flags, to compile the rust source code again. The two outputs should match bit for bit.

  • levkk 59 minutes ago
    Very cool. At first, I thought it was yet another LLM-generated demo, but no: original work of art. Super cool. Transpiling into C does seem easier than LLVM IR, and letting GCC optimize seems like this might actually work.

    Excited to see the compiler implementation when it's out -- a lot to learn from.

  • ronsor 1 hour ago
    > I put my left hand in a blender. The blender won. (Still have all my fingers, just some stitches). I will not elaborate further.

    What a shame. I would've read an article about this.

  • ahartmetz 52 minutes ago
    Wait, I thought LLVM had a C backend which could be used for the purpose of transpiling Rust to C? Turns out not for a long time, but now maybe again: https://discourse.llvm.org/t/re-ann-llvm-c-backend-still-abl...
  • nxtfari 13 minutes ago
    this is really cool but it seems very unlikely that someone targeting an exotic system not supported by rust (mostly embedded and ancient mainframe targets) would be willing to trust a beta transpiler to not inject any bugs or leaks in the process of turning rust to c. nevertheless, very cool.
  • groos 19 minutes ago
    As an ex C++ compiler developer, I heartily approve of this project. Kudos.
  • SpecialistK 34 minutes ago
    I wonder if this could be used in PPC Mac OS X, where LLVM isn't supported and most graphical applications need to use GCC 4 with Apple's SDK.
  • layer8 32 minutes ago
    Finally we can rewrite all the Rust in C. ;)
  • Cadwhisker 1 hour ago
    > The primary goal of this is support for old/obscure hardware with no LLVM/GCC support. There are still some systems out there that don't support Rust but support C.

    The landing page mentions Plan 9 as one of the systems.

  • dangoodmanUT 22 minutes ago
    i believe the author is confused

    this is the wrong direction

    (jk i read the readme)

  • Tiberium 1 hour ago
    I wonder how the performance looks like, because this can be interesting even for non-porting reasons ;)
    • adastra22 1 hour ago
      It is very unlikely that it would be faster.
      • gerdesj 1 hour ago
        Faster than what? Please finish your sentence.
        • lpribis 44 minutes ago
          Faster than rustc (the main rust compiler written in rust). Obvious from the context.
          • gerdesj 14 minutes ago
            I was hoping for some chat rather than trite twaddle. As you say: obvious.
        • keepupnow 25 minutes ago
          Sonic
  • Imustaskforhelp 59 minutes ago
    This could be used within https://bootstrappable.org/projects.html to make bootstrappability of rust incredibly much easier other than the previous route of OCaml and other things.

    I know some folks within the bootstrappable OS projects community are on Hackernews and I hope that they could take a look at this. I feel as if this project could drastically shrink down the efforts needed to get a working rust compiler in a bootstrappable manner.

    • hkalbasi 22 minutes ago
      Not really. This C code is more like a binary and compiler artifact than a source code. So it won't match the standards of bootstrap.