Add support for async/streams/futures #9582
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This adds support for loading, compiling, linking, and running components which use the [Async ABI](https://github.com/WebAssembly/component-model/blob/main/design/mvp/Async.md) along with the [`stream`, `future`, and `error-context`](WebAssembly/component-model#405) types. It also adds support for generating host bindings such that multiple host functions can be run concurrently with guest tasks -- without monopolizing the `Store`. See the [implementation RFC](bytecodealliance/rfcs#38) for details, as well as [this repo](https://github.com/dicej/component-async-demo) containing end-to-end smoke tests. This is very much a work-in progress, with a number of tasks remaining: - [ ] Avoid exposing global task IDs to guests and use per-instance IDs instead - [ ] Track `task.return` type during compilation and assert the actual and expected types match at runtime - [ ] Ensure all guest pointers are bounds-checked when lifting, lowering, or copying values - [ ] Reduce code duplication in `wasmtime_cranelift::compiler::component` - [ ] Reduce code duplication between `StoreContextMut::on_fiber` and `concurrent::on_fiber` - [ ] Minimize and/or document the use of unsafe code - [ ] Add support for `(Typed)Func::call_concurrent` per the RFC - [ ] Add support for multiplexing stream/future reads/writes and concurrent calls to guest exports per the RFC - [ ] Refactor, clean up, and unify handling of backpressure, yields, and even polling - [ ] Guard against reentrance where required (e.g. in certain fused adapter calls) - [ ] Add integration test cases covering new functionality to tests/all/component_model (starting by porting over the tests in https://github.com/dicej/component-async-demo) - [ ] Add binding generation test cases to crates/component-macro/tests - [ ] Add WAST tests to tests/misc_testsuite/component-model - [ ] Add support and test coverage for callback-less async functions (e.g. goroutines) - [ ] Switch to back to upstream `wasm-tools` once bytecodealliance/wasm-tools#1895 has been merged and released Signed-off-by: Joel Dice <[email protected]> fix clippy warnings and bench/fuzzing errors Signed-off-by: Joel Dice <[email protected]> revert atomic.wit whitespace change Signed-off-by: Joel Dice <[email protected]> fix build when component-model disabled Signed-off-by: Joel Dice <[email protected]> bless component-macro expected output Signed-off-by: Joel Dice <[email protected]> fix no-std build error Signed-off-by: Joel Dice <[email protected]> fix build with --no-default-features --features runtime,component-model Signed-off-by: Joel Dice <[email protected]> partly fix no-std build It's still broken due to the use of `std::collections::HashMap` in crates/wasmtime/src/runtime/vm/component.rs. I'll address that as part of the work to avoid exposing global task/future/stream/error-context handles to guests. Signed-off-by: Joel Dice <[email protected]> maintain per-instance tables for futures, streams, and error-contexts Signed-off-by: Joel Dice <[email protected]> refactor task/stream/future handle lifting/lowering This addresses a couple of issues: - Previously, we were passing task/stream/future/error-context reps directly to instances while keeping track of which instance had access to which rep. That worked fine in that there was no way to forge access to inaccessible reps, but it leaked information about what other instances were doing. Now we maintain per-instance waitable and error-context tables which map the reps to and from the handles which the instance sees. - The `no_std` build was broken due to use of `HashMap` in `runtime::vm::component`, which is now fixed. Note that we use one single table per instance for all tasks, streams, and futures. This is partly necessary because, when async events are delivered to the guest, it wouldn't have enough context to know which stream or future we're talking about if each unique stream and future type had its own table. So at minimum, we need to use the same table for all streams (regardless of payload type), and likewise for futures. Also, per WebAssembly/component-model#395 (comment), the plan is to move towards a shared table for all resource types as well, so this moves us in that direction. Signed-off-by: Joel Dice <[email protected]> fix wave breakage due to new stream/future/error-context types Signed-off-by: Joel Dice <[email protected]>
Signed-off-by: Joel Dice <[email protected]>
We can't statically verify a given call to `task.return` corresponds to the expected core signature appropriate for the currently running task, so we must do so at runtime. In order to make that check efficient, we intern the types. My initial plan was to use `ModuleInternedTypeIndex` and/or `VMSharedTypeIndex` for interning, but that got hairy with WasmGC considerations, so instead I added new fields to `ComponentTypes` and `ComponentTypesBuilder`. Signed-off-by: Joel Dice <[email protected]>
This implements what I proposed in https://github.com/dicej/rfcs/blob/component-async/accepted/component-model-async.md#wasmtime. Specifically, it adds: - A new `Promise` type, useful for working with concurrent operations that require access to a `Store` to make progress. - A new `PromisesUnordered` type for `await`ing multiple promises concurrently -`TypedFunc::call_concurrent` (which returns a `Promise`), allowing multiple host->guest calls to run concurrently on the same instance. - Updated `{Stream|Future}{Writer|Reader}` APIs which use `Promise` The upshot is that the embedder can now ergonomically manage arbitrary numbers of concurrent operations. Previously, this was a lot more difficult to do without accidentally starving some of the operations due to another one monopolizing the `Store`. Finally, this includes various refactorings and fixes for bugs exposed by the newer, more versatile APIs. Signed-off-by: Joel Dice <[email protected]>
Signed-off-by: Joel Dice <[email protected]>
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This adds support for loading, compiling, linking, and running components which use the Async ABI along with the
stream,future, anderror-contexttypes. It also adds support for generating host bindings such that multiple host functions can be run concurrently with guest tasks -- without monopolizing theStore.See the implementation RFC for details, as well as this repo containing end-to-end smoke tests.
This is very much a work-in progress, with a number of tasks remaining:
task.returntype during compilation and assert the actual and expected types match at runtime{stream|future}.cancel-{read|write}anderror-context.{new|debug-string}(Typed)Func::call_concurrentper the RFCwasmtime_cranelift::compiler::componentStoreContextMut::on_fiberandconcurrent::on_fiberwasm-toolsonce Add support for async ABI, futures, streams, and errors wasm-tools#1895 has been merged and released