update `component-model-async` plumbing #11123

dicej · 2025-06-24T16:38:19Z

This pulls in the latest Component Model async ABI code from the wasip3-prototyping repo, including various API refactors and spec updates.

This includes all the changes to the wasmtime crate from wasip3-prototyping except that the concurrent submodule and child submodules contain only non-functional stubs. A follow-up PR will contain the real concurrent implementation.

This commit replaces the stub functions and types in `wasmtime::runtime::component::concurrent` and its submodules with the working implementation developed in the `wasip3-prototyping` repo. For ease of review, it does not include any new tests; I'll add those in a follow-up commit. Note that this builds on bytecodealliance#11114 and bytecodealliance#11123; only the third commit is new. Signed-off-by: Joel Dice <[email protected]>

This pulls in the tests from the `wasip3-prototyping` repo, minus the ones requiring WASIp3 support in `wasmtime-wasi[-http]`, which will be PR'd separately. Note that this builds on bytecodealliance#11114, bytecodealliance#11123, and bytecodealliance#11127; only the fourth commit is new. Signed-off-by: Joel Dice <[email protected]>

This commit replaces the stub functions and types in `wasmtime::runtime::component::concurrent` and its submodules with the working implementation developed in the `wasip3-prototyping` repo. For ease of review, it does not include any new tests; I'll add those in a follow-up commit. Note that this builds on bytecodealliance#11114 and bytecodealliance#11123; only the third commit is new. Signed-off-by: Joel Dice <[email protected]>

This pulls in the tests from the `wasip3-prototyping` repo, minus the ones requiring WASIp3 support in `wasmtime-wasi[-http]`, which will be PR'd separately. Note that this builds on bytecodealliance#11114, bytecodealliance#11123, and bytecodealliance#11127; only the fourth commit is new. Signed-off-by: Joel Dice <[email protected]>

This pulls in the latest Component Model async ABI code from the `wasip3-prototyping` repo, including various API refactors and spec updates. This includes all the changes to the `wasmtime` crate from `wasip3-prototyping` _except_ that the `concurrent` submodule and child submodules contain only non-functional stubs. For that reason, and the fact that e.g. `Func::call_async` is now implemented in terms of `Func::call_concurrent`, most of the component model tests are failing. This commit is not meant to be merged as-is; a follow-up commit (to be PR'd separately) will contain the real `concurrent` implementation, at which point the tests will pass again. I'm splitting these into separate PRs to make review easier. Signed-off-by: Joel Dice <[email protected]>

This commit replaces the stub functions and types in `wasmtime::runtime::component::concurrent` and its submodules with the working implementation developed in the `wasip3-prototyping` repo. For ease of review, it does not include any new tests; I'll add those in a follow-up commit. Note that this builds on bytecodealliance#11123; only the most recent commit is new. Signed-off-by: Joel Dice <[email protected]>

This pulls in the tests from the `wasip3-prototyping` repo, minus the ones requiring WASIp3 support in `wasmtime-wasi[-http]`, which will be PR'd separately. Note that this builds on bytecodealliance#11123 and bytecodealliance#11127; only the most recent commit is new. Signed-off-by: Joel Dice <[email protected]>

No longer necessary after other refactors

(deferred for future PR)

Looks like it may have been lost by accident

This commit replaces the stub functions and types in `wasmtime::runtime::component::concurrent` and its submodules with the working implementation developed in the `wasip3-prototyping` repo. For ease of review, it does not include any new tests; I'll add those in a follow-up commit. Note that this builds on bytecodealliance#11123; only the most recent commit is new. Signed-off-by: Joel Dice <[email protected]>

alexcrichton

These are a few comments so far but I've yet to really get into the meat of this. FWIW I also rebased #11127 on top of some of the local changes I've made, mostly to ensure that the changes don't break the full build.

crates/wasmtime/src/runtime/component/func/options.rs

crates/wasmtime/src/runtime/component/values.rs

crates/wasmtime/src/runtime/component/mod.rs

alexcrichton · 2025-06-27T16:25:09Z

This may not be plausible as I haven't gotten into the "meat" yet, but I'd like to pursue ideally the ability to land this PR as-is independent of #11127. Would it be possible to avoid changing call_async in this PR and #11127 would be where the implementation changes?

github-actions · 2025-06-27T18:49:28Z

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This commit replaces the stub functions and types in `wasmtime::runtime::component::concurrent` and its submodules with the working implementation developed in the `wasip3-prototyping` repo. For ease of review, it does not include any new tests; I'll add those in a follow-up commit. Note that this builds on bytecodealliance#11123; only the most recent commit is new. Signed-off-by: Joel Dice <[email protected]>

This pulls in the tests from the `wasip3-prototyping` repo, minus the ones requiring WASIp3 support in `wasmtime-wasi[-http]`, which will be PR'd separately. Note that this builds on bytecodealliance#11123 and bytecodealliance#11127; only the most recent commit is new. Signed-off-by: Joel Dice <[email protected]>

alexcrichton · 2025-07-02T22:39:26Z

@dicej ok cba8a79 is the culmination of my attempt to keep Params: 'static out of this the async impl. That's functionally inert in this PR and won't get activated until the next PR. With that I'm going to call typed.rs and func.rs done. I'm still concerned about the two different paths through the code but this seems about as good as we can get it for now so I think it's best to tackle that in the next PR, and/or as a follow-up in the future.

I ran out of time to get to the rest of host.rs today, but I'll work on benchmarking tomorrow and scanning through host.rs.

crates/wasmtime/src/runtime/component/func/typed.rs

dicej · 2025-07-02T22:50:54Z

crates/wasmtime/src/runtime/component/func/typed.rs

+                Self::lower_args(cx, ty, dst, params)
+            })?;
+
+            // TODO: need to place a dtor on the stack referencing the store


This part is definitely critical.

Yeah my thinking is that this'll be easier to write up in the next PR once concurrent.rs is filled out

Speeds up host calls by ~20% and puts them back on parity with the beforehand numbers Wasmtime has.

Use slices for both instead of vecs for one and slices for the other. Required some slight rejiggering. Apparently one can solve a closure problem with another closure, then one surely has no more closure problems.

alexcrichton · 2025-07-03T20:17:24Z

Benchmarking update:

As-is this PR yields these numbers in the preexisting call.rs benchmarks:

not amazing, not awful.

I ran ./benches/wasmtime-serve-rps.sh and saw no measurable difference with before/after.

alexcrichton

Ok @dicej I'm comfortable with everything here. Mind giving it another once-over on your end to confirm too? If you're ok with it all feel free to enqueue for merge.

alexcrichton · 2025-07-03T20:20:28Z

I'll say I was originally planning to squash everything into one commit but we had some merge commits along the way which makes that slightly annoying so I'm content to let github merges figure out how to squash it instead.

alexcrichton · 2025-07-03T20:24:29Z

(also, to reiterate, thank you again for being patient with my review on this!)

dicej · 2025-07-03T22:04:37Z

Thanks for persisting with this, @alexcrichton! Your changes look good to me.

This commit replaces the stub functions and types in `wasmtime::runtime::component::concurrent` and its submodules with the working implementation developed in the `wasip3-prototyping` repo. For ease of review, it does not include any new tests; I'll add those in a follow-up commit. Note that this builds on bytecodealliance#11123; only the most recent commit is new. Signed-off-by: Joel Dice <[email protected]>

This pulls in the tests from the `wasip3-prototyping` repo, minus the ones requiring WASIp3 support in `wasmtime-wasi[-http]`, which will be PR'd separately. Note that this builds on bytecodealliance#11123 and bytecodealliance#11127; only the most recent commit is new. Signed-off-by: Joel Dice <[email protected]>

…)" This reverts commit b221fca.

This reverts commit b221fca.

This pulls in the tests from the `wasip3-prototyping` repo, minus the ones requiring WASIp3 support in `wasmtime-wasi[-http]`, which will be PR'd separately. Note that this builds on bytecodealliance#11123 and bytecodealliance#11127; only the most recent commit is new. Signed-off-by: Joel Dice <[email protected]>

* implement Component Model async ABI This commit replaces the stub functions and types in `wasmtime::runtime::component::concurrent` and its submodules with the working implementation developed in the `wasip3-prototyping` repo. For ease of review, it does not include any new tests; I'll add those in a follow-up commit. Note that this builds on #11123; only the most recent commit is new. Signed-off-by: Joel Dice <[email protected]> * clear params pointer in `call_async` when future is dropped This ensures that the closure we pass to `prepare_call` will never see a stale pointer. Note that this could potentially be made more efficient; I'm starting with a simple solution, and we can refine from there. Signed-off-by: Joel Dice <[email protected]> * Remove unsafety from accessing concurrent async state * Remove a dead variant when async is disabled * Add tests for `tls.rs` unsafe code * Refactor `AbortHandle` * Don't close over the entire future in the `AbortHandle`, instead change it to just the bare minimum state to manage aborts. * Move aborting logic into a helper `AbortHandle::run` function which handles the is-this-aborted-check internally. * Refactor some logic around spawns how `AbortHandle` is managed/created. * Internalize some functions/types * add FIXME comment to `states.rs` Signed-off-by: Joel Dice <[email protected]> * reference issue 11190 in `table.rs` TODO Signed-off-by: Joel Dice <[email protected]> * switch `use` directives to conventional syntax Signed-off-by: Joel Dice <[email protected]> * remove redundant accessor methods Signed-off-by: Joel Dice <[email protected]> * reference issue 11191 in `yield` TODO comments Signed-off-by: Joel Dice <[email protected]> * replace `dummy_waker` with `Waker::noop` Signed-off-by: Joel Dice <[email protected]> * remove obsolete `AsyncState::spawned_tasks` field Signed-off-by: Joel Dice <[email protected]> * only call post-return automatically for `call_concurrent` This restores the original behavior of requiring explicit post-return calls for `call[_async]` invocations. Signed-off-by: Joel Dice <[email protected]> * Favor function arguments before closures * Simplify `watch` a bit Mostly move unnecessary state out of the `Arc`. * fix task handle leaks and add test coverage We weren't always disposing of guest or host task handles once they became unreachable. This adds a couple of hidden methods which integration tests may use to guard against use-after-delete, double-delete, and leak bugs regarding waitable handles. It also tightens up handle management in `concurrent.rs` to ensure those tests pass. Signed-off-by: Joel Dice <[email protected]> * Encapsulate type erasure in stream buffers Don't rely on all buffers to handle `TypeId` and assertions and such, instead have a helper type which is the one location of the assertions and everything else can stay typed. * Remove some methods ending in underscores * Refactor unsafety in `buffers.rs` Mostly move away from raw pointers and instead use utilities like `&[MaybeUninit<T>]`. Also make `WriteBuffer` an `unsafe` trait after absorbing the `TakeBuffer` trait. Update all safety-related comments here and there too. * remove task on drop in `TypedFunc::call_async` This avoids the need for an `Arc`. Signed-off-by: Joel Dice <[email protected]> * remove obsolete clause from `FutureReader::read` docs Signed-off-by: Joel Dice <[email protected]> * unhide and expand docs for `WriteBuffer` and `ReadBuffer` Signed-off-by: Joel Dice <[email protected]> * add optional `component-model-async-bytes` feature This gates interop with the `bytes` crate, making it optional and non-default. Signed-off-by: Joel Dice <[email protected]> --------- Signed-off-by: Joel Dice <[email protected]> Co-authored-by: Alex Crichton <[email protected]>

dicej mentioned this pull request Jun 24, 2025

implement Component Model async ABI #11127

Merged

dicej requested a review from alexcrichton June 24, 2025 18:38

github-actions bot added the wasmtime:c-api Issues pertaining to the C API. label Jun 24, 2025

dicej mentioned this pull request Jun 25, 2025

add Component Model async ABI tests #11136

Merged

dicej force-pushed the cm-async-plumbing branch from 54c7113 to acd2e1e Compare June 26, 2025 22:48

alexcrichton added 6 commits June 27, 2025 08:03

Undo wit-bindgen changes

02fd9fc

No longer necessary after other refactors

Move back to crates.io-based wit-bindgen

f07063d

Undo upgrade of http-body-util

53f776d

(deferred for future PR)

Add back in arbitrary use of async

5ff5dda

Looks like it may have been lost by accident

Make imports more conventional for Wasmtime

74cda3b

Some minor changes

a87fe05

alexcrichton added 3 commits June 27, 2025 08:52

Privatize a component field

079659c

Cut down a bit on #[cfg]

daab794

Undo a no-longer-necessary pub

8559973

alexcrichton reviewed Jun 27, 2025

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crates/wasmtime/src/runtime/component/func/options.rs Outdated Show resolved Hide resolved

crates/wasmtime/src/runtime/component/values.rs Outdated Show resolved Hide resolved

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github-actions bot added fuzzing Issues related to our fuzzing infrastructure wasmtime:api Related to the API of the `wasmtime` crate itself labels Jun 27, 2025

alexcrichton added 2 commits July 2, 2025 14:26

Remove outdated safety comment

2184908

Refactor to not require Params: 'static on call_async

cba8a79

dicej commented Jul 2, 2025

View reviewed changes

alexcrichton added 5 commits July 2, 2025 16:34

Remove no-longer-necessary SAFETY comment

05e13ed

Fix typos

5f2478d

Add a fast-path with no Box for sync host functions

883662e

Speeds up host calls by ~20% and puts them back on parity with the beforehand numbers Wasmtime has.

Merge remote-tracking branch 'origin/main' into cm-async-plumbing

2805417

Synchronize signatures of async/concurrent dynamic calls

80fdb80

Use slices for both instead of vecs for one and slices for the other. Required some slight rejiggering. Apparently one can solve a closure problem with another closure, then one surely has no more closure problems.

Fix non-cm-async build

0dedf6e

alexcrichton approved these changes Jul 3, 2025

View reviewed changes

dicej added this pull request to the merge queue Jul 3, 2025

Merged via the queue into bytecodealliance:main with commit b221fca Jul 3, 2025
44 checks passed

dicej deleted the cm-async-plumbing branch July 3, 2025 22:25

alexcrichton added a commit to alexcrichton/wasmtime that referenced this pull request Jul 7, 2025

Revert "update component-model-async plumbing (bytecodealliance#11123…

13837b0

…)" This reverts commit b221fca.

alexcrichton mentioned this pull request Jul 7, 2025

[35.0.0] Revert "update component-model-async plumbing (#11123)" #11192

Merged

alexcrichton added a commit that referenced this pull request Jul 7, 2025

Revert "update component-model-async plumbing (#11123)" (#11192)

1112ac1

This reverts commit b221fca.

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