Stream: cranelift

Topic: cg_clif can bootstrap rustc

bjorn3 (Jul 02 2020 at 18:23):

https://github.com/bjorn3/rustc_codegen_cranelift/issues/743#issuecomment-651108168

Cross posting from https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/bootstrap.20rustc.20using.20cg_clif

bjorn3 (Jul 02 2020 at 18:23):

Depends on https://github.com/bytecodealliance/wasmtime/pull/1559 and https://github.com/bytecodealliance/wasmtime/pull/1939

Chris Fallin (Jul 02 2020 at 18:30):

Very nice!

Joey Gouly (Jul 03 2020 at 09:35):

@bjorn3 on x86 I assume?

Joey Gouly (Jul 03 2020 at 09:36):

Wondering how hard it would be to try on my arm64 machine

bjorn3 (Jul 03 2020 at 09:40):

Yes I used x86_64. arm64 doesn't yet work with cg_clif. The aarch64 backend doesn't yet support 128bit integers. Those are used very extensively in the const eval part of rustc. In fact the last thing I had to solve before cg_clif could bootstrap ristc was adding 128bit support to cranelift_frontend::Switch.

Joey Gouly (Jul 03 2020 at 09:42):

Does cranelift not have legalisation for 128 bit integers?

Benjamin Bouvier (Jul 03 2020 at 09:43):

We do have some of it; it might be disabled for the aarch64 backend, though, not sure.

bjorn3 (Jul 03 2020 at 09:54):

No new style backends have the necessary legalizations enabled. They only enable a small subset.

bjorn3 (Jul 03 2020 at 09:55):

Also for function parameters and calls the necessary legalizations are part of the abi handling for the old style backends.

bjorn3 (Jul 03 2020 at 09:56):

https://github.com/bytecodealliance/wasmtime/blob/08efcbd9d5638c3d1ff2989f00e65c22ddc3c803/cranelift/codegen/src/legalizer/boundary.rs#L465-L477

bjorn3 (Jul 13 2020 at 10:45):

Can somebody please review https://github.com/bytecodealliance/wasmtime/pull/1939? It should be easy to do.

bjorn3 (Jul 16 2020 at 18:56):

@Alex Crichton On https://github.com/bytecodealliance/wasmtime/pull/1559 the macOS builder failed without log. Can you restart it?

Alex Crichton (Jul 16 2020 at 18:56):

eh I wouldn't worry about it, unfortunately we can't restart just one builder

Alex Crichton (Jul 16 2020 at 18:57):

and it passed debug tests on macos so it's unlikely to fail in release anyway

bjorn3 (Jul 16 2020 at 18:58):

okay

bjorn3 (Jul 17 2020 at 11:55):

https://github.com/bytecodealliance/wasmtime/pull/1559 has been merged, so it is no longer necessary to patch cg_clif to bootstrap rustc. Only rustc needs to be patched to integrate with cg_clif. https://github.com/bjorn3/rustc_codegen_cranelift/issues/743#issuecomment-660046919

Benjamin Bouvier (Jul 17 2020 at 11:57):

Great work @bjorn3 !

bjorn3 (Jul 17 2020 at 11:57):

Thanks!

Last updated: Dec 23 2024 at 12:05 UTC