I'm not a smart Compiler or Rust hacker but I'm too curious to let this go. Is `count_insn` effectively a nop here? If not, how is the space required for the generated assembly calculated without count_insn being passed asm?

`llfty` seems to be a function stub for the inline assembly and v should be the bytevector returned by LLVM's assembler. The fact that the majority of this patch is readable to a noob like myself is great fun. And feel free to ignore, I know you guys have lots more important things to do. :)