[tracking] .NET support for post-MVP WebAssembly Proposals

[lambdageek]

Summary

This issue attempts to collect the post-MVP WebAssembly spec proposals. The goal is to provide a convenient place to collect issues for the individual proposals and the status of each proposal with respect to the .NET runtime.

This list of in-progress proposals is from WebAssembly/proposals@0099331

Legend
not currently planned	⏹️
not applicable or no action needed	🈚
supported	🏁
in progress	🏃
under consideration	🤔
needs investigation	🐌

For the status of support for each proposal by various popular WebAssembly engines, see https://webassembly.org/roadmap/

Accepted proposals

These are the proposals in https://github.com/WebAssembly/spec/tree/main/proposals that have been merged into the spec

Proposal	dotnet/runtime issue	.NET status
bulk memory operations		🏁 1
multi-value		🈚2
non-trapping float-to-int conversion	3	🏁
reference types		🐌
sign extension operators		🏁 4
SIMD	#53730	🏁

Phase 4 - Standardize the feature (WG)

Proposal	dotnet/runtime Issue	.NET status
tailcall	#94352	🐌
extended constant expressions		🐌
typed function references		🐌
garbage collection	#94420	⏹️
multiple memories		🐌
threads	#68162	🏃
relaxed SIMD		🐌

Phase 3 - Implementation Phase (WG + CG)

Proposal	dotnet/runtime issue	.NET status
custom annotation syntax in the text format	-	🈚5
memory64	#94108	🐌
exception handling	#84573	🏁
web content security policy	#68374	🏁
branch hinting		🐌
JS promise integration	#80904	🐌
type reflection for WebAssembly JavaScript API		🐌

Phase 2 - Proposed Spec Text Available (WG + CG)

Proposal	dotnet/runtime issue	.NET status
ECMAScript module integration		🐌
relaxed dead code validation		🐌
numeric values in WAT data segments		🐌
instrument and tracing technology		🐌
extended name section		🐌

Phase 1 - Feature Proposal (CG)

Proposal	dotnet/runtime issue	.NET status
type imports		🐌
component model		🐌
WebAssembly C and C++ API		🐌
flexible vectors		🐌
call tags		🐌
stack switching		🐌
constant time		🐌
JS customization for GC Objects		🐌
memory control		🐌
reference-typed strings		🐌
profiles		🐌
JS string builtins		🐌
rounding variants		🐌
shared everything threads	#96629	🐌

Footnotes

1. Supported by toolchain ↩

2. There may be some micro-optimization opportunities for the jiterpreter to return multiple values. Interpreter and AOT use the C stack to return .NET valuetypes not the WASM stack. ↩

3. Supported by toolchain, intrinsics added together with SIMD in https://github.com/dotnet/runtime/issues/53730 ↩

4. Supported by toolchain ↩

5. .NET does not use the WAT text format directly ↩

[Anutrix]

Minor note: ⏸️ symbol seems like 'feature is paused but might continue' when it actually means not applicable or no action needed aka it's conclusion has been reached.

[lambdageek]

Minor note: ⏸️ symbol seems like 'feature is paused but might continue' when it actually means not applicable or no action needed aka it's conclusion has been reached.

Ok, replaced it with 🈚 which apparently means "free of charge". that's pretty close, maybe. There's also 🉑 which is "acceptable". If this is all too silly, maybe I'll just write "N/A"

[lambdageek]

We should also add the "thread spawning" aka "shared everything" proposal once it is a bit more mature https://github.com/WebAssembly/shared-everything-threads/blob/main/proposals/thread-spawn/Overview.md

Update 2024-01-08 added