implement Component Model async ABI (#11127)

* 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]>

Author: dicej

Cargo.lock

@@ -62,6 +62,7 @@ smallvec = { workspace = true, optional = true }
 hashbrown = { workspace = true, features = ["default-hasher"] }
 bitflags = { workspace = true }
 futures = { workspace = true, features = ["alloc"], optional = true }
+bytes = { workspace = true, optional = true }
 
 [target.'cfg(target_os = "windows")'.dependencies.windows-sys]
 workspace = true
@@ -391,4 +392,12 @@ component-model-async = [
   "component-model",
   "std",
   "wasmtime-component-macro?/component-model-async",
+  "dep:futures",
+  "futures/std",
+]
+
+# Enables support for `stream` interop with the `bytes` crate.
+component-model-async-bytes = [
+  "component-model-async",
+  "dep:bytes",
 ]