[cfallin]

Cranelift is a general-purpose compiler like LLVM is, but its goals are different: it is targeted toward applications like JITs where faster compilation is important. It is intended to be a peer of browser JITs' optimizing tiers. In our README [0] we link some results where we're ~14% slower than LLVM but with ~10x faster compilation.

We also have an explicit focus on correctness, simplicity, and verification. One could argue that in practice LLVM is used everywhere and has dozens of active core contributors, that bugs and missed optimizations are shallow at that scale, and it's hard to compete with that; and there is some merit in that... but our codebase is two orders of magnitude smaller, and we're actively engaging with academics and designing things -- our lowering DSL, our regalloc's symbolic verifier, our fuzzing-first approach -- to get the most mileage we can out of our efforts. It seems to be working OK so far!

[0] https://github.com/bytecodealliance/wasmtime/blob/main/crane...

[tialaramex]

> explicit focus on correctness, simplicity and verification

Does this mean Cranelift has a clearer view of what its IR really means than, say, LLVM? It seems to me that being very clear-eyed on this will be important as C and C++ get ready to bite the bullet (perhaps this decade) and formally document how pointer provenance works in their languages, and perhaps Aria's provenance "experiment" in Rust begins the journey to stabilisation.

[cfallin]

That's the goal at least! We explicitly do not have a notion of "undef" or "poison" values in our IR, and to the largest degree possible we want determinism (modulo e.g. some NaN-related stuff right now). Our current discussion with some researchers wanting to formally verify our lowerings will likely push us toward the start of some formal spec for the IR as well, though exactly how that will work or be maintained is not yet decided.

I'm not super-familiar with the pointer provenance work in Rust but I'll read more about this; thanks for the mention!

[nindalf]

How far do you think the effort to integrate cranelift as an optional backend to rustc is from shipping?

[cfallin]

That's a good question for bjorn3, the leader of that effort; they periodically publish status updates. Over on the Reddit discussion someone pointed to this GitHub issue too: https://github.com/rust-lang/rust/pull/81746#issuecomment-10...