Trap handling for Windows ARM64

[Berrysoft]

After #4990 merged, we can build wasmtime for Windows ARM64, and it should work without trap handling.

We now need to add trap handling to make it totally work.

[Berrysoft]

wasmtime/cranelift/codegen/src/isa/aarch64/mod.rs

Lines 151 to 154 in 3fa545b

	UnwindInfoKind::Windows => {
	// TODO: support Windows unwind info on AArch64
	None
	}

[hwoodiwiss]

Is this something that's being looked at actively at the moment, and would a community contribution be welcome?

[cfallin]

No one has indicated they're working on it, so if you or anyone who is familiar with Windows on Arm is willing to build it, we'd very much welcome it!

[dpaoliello]

It's hackathon week at Microsoft, so I'm going to have a go at this as my project...

[alexcrichton]

Oh nice, that'd be great! If you have any questions feel free to reach out here or on Zulip

[dpaoliello]

I have a draft PR: #9266

Update: I misread the stack, looks like it's a crash due to a "malformed function table during unwind" - investigating further...

[dpaoliello]

Update: I got everything working (required a more careful reading of the spec and how wasmtime emits instructions).
PR has been published.

[cfallin]

Very exciting, thanks @dpaoliello! It looks like Alex has looked at the PR at a high level; I'll do a detailed review.

[kpreisser]

Thank you very much for implementing unwind support for Windows Arm64, and providing release artifacts!
When running the unit tests of wasmtime-dotnet on Windows 11 Version 23H2 Arm64 (using the wasmtime-dev-aarch64-windows-c-api.zip artifact of the latest dev release), all tests now succeed.