Known Limitations of Translation

This document tracks things that we know the translator can't handle, as well as things it probably won't ever handle.


  • variadic function definitions (blocking Rust issue)
  • preserving comments (work in progress)
  • long double and _Complex types (partially blocked by Rust language)
  • Non x86/64 SIMD function/types and x86/64 SIMD function/types which have no rust equivalent

Unimplemented, might be implementable but very low priority

  • GNU packed structs (Rust has #[repr(packed)] compatible with #[repr(C)])
  • inline functions (Rust has #[inline])
  • restrict pointers (Rust has references)
  • inline assembly
  • macros

Likely won't ever support

  • longjmp/setjmp Although there are LLVM intrinsics for these, it is unclear how these interact with Rust (esp. idiomatic Rust).
  • jumps into and out of statement expressions We support GNU C statement expressions, but we can not handle jumping into or out of these. Both entry and exit into the expression have to be through the usual fall-through evaluation of the expression.