Generalize WASI to other Wasm engines #79
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evidently I hadn't run the tests myself yet 😶 @kateinoigakukun tests should now be green |
| @@ -47,3 +49,23 @@ public struct CanonicalCallContext { | |||
| return UnsafeGuestRawPointer(memorySpace: guestMemory, offset: new) | |||
| } | |||
| } | |||
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| public struct GuestMemory: BaseGuestMemory { | |||
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| public struct GuestMemory: BaseGuestMemory { | |
| public struct WasmKitGuestMemory: GuestMemory { |
I personally prefer avoiding Base here
Package.swift
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| @@ -15,6 +15,10 @@ let package = Package( | |||
| name: "WASI", | |||
| targets: ["WASI"] | |||
| ), | |||
| .library( | |||
| name: "WASIBase", | |||
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| name: "WASIBase", | |
| name: "WASI", |
I'd like to make this engine agnostic target as bare WASI, and the engine dependent one as WasmKitWASI
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this is ready from my end! The only thing I haven't been able to test yet is the performance of using an existential |
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I'll merge this once I check on my local 👍 |
| let (name, type) = entry | ||
| functions[name] = HostFunction(type: type) { _, _ in | ||
| functions[name] = WASIHostFunction(type: type) { _, _ in | ||
| print("\"\(name)\" not implemented yet") | ||
| return [.i32(WASIAbi.Errno.ENOSYS.rawValue)] | ||
| } | ||
| } | ||
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| func withMemoryBuffer<T>( |
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I should note that this function is basically now a no-op since this work is offloaded to WasmKitWASI. I wanted to minimize the diff to begin with for ease of review but it might make sense to remove this now. @kateinoigakukun would you prefer that I do it in this PR or in a follow-up?
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Thanks for minimizing diff! I prefer a following up way
This PR enables layering the WASI module on top of other Wasm engines, such as JavaScriptCore.
To achieve this, it's worth first noting that the only real dependency that WASI had on WasmKit was in reading/writing host memory (via
UnsafeGuestPointer) as well as the small set of core WasmValuetypes. Accordingly, I've split these bits out into a separateWasmTypesmodule and created aWASIBasepackage that depends only onWasmTypes. I created aBaseGuestMemoryprotocol that can be implemented by engines, and kept theGuestMemorytype as WasmKit's concrete implementation.I believe this maintains full source compatibility with previous versions, but I'm not sure if the API design is ideal. Certainly open to feedback on how this could be improvededit: there is some minor API breakage in that UnsafeGuest[Raw]Pointer now uses the protocol-ized BaseGuestMemory and requires a
countwhen obtaining a pointer to host memory. If we really wanted full source compat we could create more pointer variants that take the concrete WasmKit.GuestMemory but I’m not sure it’s worth it.