Comment by tialaramex
Comment by tialaramex 7 hours ago
Sure, or perhaps since LLVM devs like niches so much they might decide to RIIR.
For me the big advantage of Cranelift isn't that it's written in Rust it's that they seem to have invested more into coherent semantics. I do not want to write code which is correct but is miscompiled because the compiler internal semantics are nonsense and that's a small but noticeable problem in LLVM.
You can write contorted (but safe) Rust which LLVM just plainly miscompiles, the rust layer is like "Make local variable A, and local variable B" Ok says LLVM, "and now is the address of A the same as the address of B?" "No", says LLVM those are different, not the same variable so different addresses. OK says the Rust. Now, subtract the smaller from the larger and tell me the number you got. "Zero" triumphantly proclaims LLVM having deduced that we don't need A or B so there's no need to store them anywhere, but forgotten that it promised their addresses aren't the same... Oops.
That example is silly, but it's hard to be sure how many large codebases might tickle equivalent LLVM miscompilation, which is not good.