1720381 - Handle alignment better for Wasm exception payload fields

Status: RESOLVED FIXED

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

Description

[Asumu Takikawa]

It was suggested in review comments on https://phabricator.services.mozilla.com/D110851 that Wasm exception handling code should deal with alignment better. In particular, a Wasm tag could use a mechanism similar to GC proposal structs with StructType and StructLayout in order to ensure alignment is taken into account for the buffer size and reading/writing values from an exception.

Comment 1

[Asumu Takikawa]

Attachment: Bug 1720381 - Handle alignment for Wasm exception payloads

This patch properly aligns exception payload buffers, and
simplified the handling of buffer offsets in the Baseline
compiler.

Comment 2

[Asumu Takikawa]

I've added a WIP patch to address this alignment issue. The patch should work and pass tests, but there's some refactoring needed that could use some feedback (more detail in phabricator comments) hence the WIP flag.

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/7c19fa0eb0e0
Handle alignment for Wasm exception payloads r=rhunt

Comment 4

[Cosmin Sabou [:CosminS]]

https://hg.mozilla.org/mozilla-central/rev/7c19fa0eb0e0