1977692 - ToWebAssemblyValue for i31ref should permit -0

Status: RESOLVED FIXED

(Core :: JavaScript: WebAssembly, task, P3)

Description

[Ryan Hunt [:rhunt]]

See [1] step 6.4: Else if v is a Number and v is equal to ? ToInt32(v) and ℝ(v) < 2^30 and ℝ(v) ⩾ -2^30

ToInt32(-0) [2] will return +0, and -0 == 0, so we should succeed in the conversion to i31ref. The result should be ref.i31 0.

We have tests of the opposite that should be updated [3].

[1] https://webassembly.github.io/gc/js-api/index.html#towebassemblyvalue
[2] https://tc39.es/ecma262/multipage/abstract-operations.html#sec-toint32
[3] https://searchfox.org/mozilla-central/rev/4e4c6befbae5dccbe4c718d6871f75c16d97f82d/js/src/jit-test/tests/wasm/gc/i31ref.js#9

Comment 1

[Ben Visness [:bvisness]]

Attachment: Bug 1977692: Allow -0 to convert to i31ref. r=rhunt

This required changing the C++ conversion path (deep in
ToWebAssemblyValue) and the JIT entry path.

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/1289cf86f685
https://hg.mozilla.org/integration/autoland/rev/d78ccee4066d
Allow -0 to convert to i31ref. r=rhunt

Comment 3

[agoloman]

https://hg.mozilla.org/mozilla-central/rev/d78ccee4066d