Propose to phase 4

[Ms2ger]

Entry requirements:

• Two or more Web VMs implement the feature.
  • SpiderMonkey and V8 implement.
• At least one toolchain implements the feature.
• The formalization and the reference interpreter are usually updated (though these two can be done as part of step 3 at the Working Group chair's discretion).
• Community Group has reached consensus in support of the feature.

[kripken]

For toolchain support in emscripten specifically we'll need to stop "legalizing" i64s into pairs of i32s, and handle the receiving of bigints in the JS support code. I hope to look into that soon.

[xtuc]

wasm-bindgen allows the transformation of Rust's u64 and i64 to JS' BigInt https://github.com/rustwasm/wasm-bindgen/pull/188/files.

[CryZe]

wasm-bindgen allows the transformation of Rust's u64 and i64 to JS' BigInt https://github.com/rustwasm/wasm-bindgen/pull/188/files.

That's more of a workaround though, rather than implementing the proposal. So just like emscripten, it would need to be rewritten.

[xtuc]

@CryZe you are right, I misread the PR. wasm-bindgen also lowers them

[kripken]

The emscripten work for BigInt has landed: emscripten-core/emscripten#10860

That uses BigInts on wasm imports and exports of i64s, so it changes the FFI between wasm and JS. (So far we don't use BigInt64Array as that isn't on the FFI boundary, and the benefit to us isn't clear). Tested with v8, everything looks good.

[Ms2ger]

CG approved in the 2020-05-12 meeting.