Add windows support

[oovm]

I want to study examples on Windows platform, but wasmtime cannot be compiled on Windows, missing FiberStack:

wasmfxtime/crates/runtime/src/fibre/mod.rs

Line 18 in b783f55

compile_error!("fibers are not supported on this platform");

But there is a Windows version of FiberStack:

wasmfxtime/crates/fiber/src/lib.rs

Lines 9 to 22 in b783f55

	cfg_if::cfg_if! {
	if #[cfg(windows)] {
	mod windows;
	use windows as imp;
	} else if #[cfg(unix)] {
	mod unix;
	use unix as imp;
	} else {
	compile_error!("fibers are not supported on this platform");
	}
	}
	/// Represents an execution stack to use for a fiber.
	pub struct FiberStack(imp::FiberStack);

Is there any difference between the two?

[dhil]

The baseline implementation may work on Windows. Try to build with cargo build --features=wasmfx_baseline. Though, no guarantees as we currently only aim to support x64 Linux. I suppose you can build it in WSL too.

[oovm]

I am using

[dependencies.wasmtime]
version = "*"
features = ["async", "component-model", "gc", "wasmfx_baseline"]
git = "https://github.com/wasmfx/wasmfxtime"

and

let mut config = Config::new();
{
    // FIX: exceptions proposal not enabled
    config.wasm_exceptions(true);
    // FIX: typed continuations support is not enabled
    config.wasm_typed_continuations(true);
}

But always hit

wasmfxtime/crates/wasmtime/src/runtime/vm/continuation.rs

Line 790 in e214959

panic!("attempt to execute continuation::optimized::cont_new with `typed_continuation_baseline_implementation` toggled!")

and last call was

wasmfxtime/crates/wasmtime/src/runtime/vm/libcalls.rs

Lines 836 to 847 in e214959

	// Builtins for continuations. These are thin wrappers around the
	// respective definitions in continuation.rs.
	fn tc_cont_new(
	instance: &mut Instance,
	func: *mut u8,
	param_count: u32,
	result_count: u32,
	) -> Result<*mut u8, TrapReason> {
	let ans =
	crate::vm::continuation::optimized::cont_new(instance, func, param_count, result_count)?;
	Ok(ans.cast::<u8>())
	}

[dhil]

Thanks for you patch! The whole baseline/optimized toggling is a bit of a mess (c.f. #172), something which we will clean up soon. The baseline is built directly on top of wasmtime fiber, which has Windows support, whereas with the "optimized" (should really be called development version or something like that) we use a bespoke implementation, where we are currently only developing and testing for x86_64 Linux.