Stream: git-wasmtime

Topic: wasmtime / PR #12427 Check may-leave flags in trampolines...

Wasmtime GitHub notifications bot (Jan 25 2026 at 03:09):

alexcrichton opened PR #12427 from alexcrichton:fixup-and-check-may-leave to bytecodealliance:main:

This commit moves all may-leave flag handling into compiled trampolines rather than doing this in Rust. This means it can't be forgotten on the Rust side of things and will be slightly more efficient to boot. This then additionally exempts some intrinsics from checking may-leave since Wasmtime erroneously checked when it shouldn't have.

Closes #12397
Closes #12403

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Wasmtime GitHub notifications bot (Jan 25 2026 at 03:09):

alexcrichton commented on PR #12427:

This is a draft for now because the new tests I added are failing (some intrinsics aren't supporting being called in post-return for example) and I need to bottom that out.

Wasmtime GitHub notifications bot (Jan 25 2026 at 04:08):

github-actions[bot] added the label wasmtime:api on PR #12427.

Wasmtime GitHub notifications bot (Jan 29 2026 at 17:54):

alexcrichton commented on PR #12427:

Semi-blocked on https://bytecodealliance.zulipchat.com/#narrow/channel/217126-wasmtime/topic/Is.20anyone.20using.20.60WasmStr.60.20or.20.60WasmList.3CT.3E.60.20as.20a.20guest.20return/with/570861394

Wasmtime GitHub notifications bot (Jan 29 2026 at 17:59):

alexcrichton commented on PR #12427:

In discussion with @dicej on this we see 1 of two paths forward:

1. Delete Func::post_return as a Wasmtime API. This would mean that post-return is always called automatically, and that'll untangle some internals to avoid the panics happening here.
2. Fix the internals, probably by making them a bit more complicated, and keep Func::post_return as-is.

We're currently thinking of pursuing (1) here pending if anyonoe has use cases on Zulip.

Wasmtime GitHub notifications bot (Feb 03 2026 at 19:26):

alexcrichton updated PR #12427.

Wasmtime GitHub notifications bot (Feb 03 2026 at 19:30):

alexcrichton updated PR #12427.

Wasmtime GitHub notifications bot (Feb 03 2026 at 19:40):

alexcrichton updated PR #12427.

Wasmtime GitHub notifications bot (Feb 03 2026 at 19:40):

alexcrichton requested dicej for a review on PR #12427.

Wasmtime GitHub notifications bot (Feb 03 2026 at 19:40):

alexcrichton has marked PR #12427 as ready for review.

Wasmtime GitHub notifications bot (Feb 03 2026 at 19:40):

alexcrichton requested cfallin for a review on PR #12427.

Wasmtime GitHub notifications bot (Feb 03 2026 at 19:40):

alexcrichton requested wasmtime-compiler-reviewers for a review on PR #12427.

Wasmtime GitHub notifications bot (Feb 03 2026 at 19:40):

alexcrichton requested wasmtime-core-reviewers for a review on PR #12427.

Wasmtime GitHub notifications bot (Feb 03 2026 at 19:46):

fitzgen submitted PR review:

Nice!

Wasmtime GitHub notifications bot (Feb 03 2026 at 20:01):

alexcrichton added PR #12427 Check may-leave flags in trampolines, not Rust to the merge queue.

Wasmtime GitHub notifications bot (Feb 03 2026 at 20:26):

alexcrichton merged PR #12427.

Wasmtime GitHub notifications bot (Feb 03 2026 at 20:26):

alexcrichton removed PR #12427 Check may-leave flags in trampolines, not Rust from the merge queue.

Last updated: Feb 24 2026 at 07:22 UTC