It looks like this is our fork. There was a time when we only carried a few patches, but it looks quite monstrous at the moment.
Rust does not base it’s fork off of a released version of LLVM. It is an arbitrary commit from upstream LLVM. LLVM upgrades do break Rust’s bindings but that is usually not the hardest part of the upgrades. Rather, getting all of Rust’s supported platforms to pass CI again is. Our MinGW port is especially troublesome, as upstream support has degraded over the years.
It looks like we are currently carrying a merge of the fastcomp fork, though when I originally merged fastcomp support, we did not literally merge with fastcomp, we just created a minimal patch that created a fastcomp target with fastcomp-compatible IR.
If we try to pull in an updated wasm backend I’d prefer to upgrade LLVM from upstream and not cherry-pick more stuff.
cc @TimNN did the last upgrade.