wasm: support rt-multi-thread with wasm32-wasi-preview1-threads (#6510)

.github/workflows/ci.yml

@@ -909,16 +909,21 @@ jobs:
         working-directory: tokio
 
   wasm32-wasi:
-    name: wasm32-wasi
+    name: ${{ matrix.target }}
     needs: basics
     runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        target:
+          - wasm32-wasi
+          - wasm32-wasi-preview1-threads
     steps:
       - uses: actions/checkout@v4
       - name: Install Rust ${{ env.rust_stable }}
         uses: dtolnay/rust-toolchain@stable
         with:
           toolchain: ${{ env.rust_stable }}
-          targets: wasm32-wasi
+          targets: ${{ matrix.target }}
 
       # Install dependencies
       - name: Install cargo-hack, wasmtime, and cargo-wasi
@@ -928,27 +933,39 @@ jobs:
 
       - uses: Swatinem/rust-cache@v2
       - name: WASI test tokio full
-        run: cargo test -p tokio --target wasm32-wasi --features full
+        run: cargo test -p tokio --target ${{ matrix.target }} --features full
         env:
           CARGO_TARGET_WASM32_WASI_RUNNER: "wasmtime run --"
-          RUSTFLAGS: --cfg tokio_unstable -Dwarnings
+          CARGO_TARGET_WASM32_WASI_PREVIEW1_THREADS_RUNNER: "wasmtime run -W bulk-memory=y -W threads=y -S threads=y --"
+          RUSTFLAGS: --cfg tokio_unstable -Dwarnings -C target-feature=+atomics,+bulk-memory -C link-args=--max-memory=67108864
 
       - name: WASI test tokio-util full
-        run: cargo test -p tokio-util --target wasm32-wasi --features full
+        run: cargo test -p tokio-util --target ${{ matrix.target }} --features full
         env:
           CARGO_TARGET_WASM32_WASI_RUNNER: "wasmtime run --"
-          RUSTFLAGS: --cfg tokio_unstable -Dwarnings
+          CARGO_TARGET_WASM32_WASI_PREVIEW1_THREADS_RUNNER: "wasmtime run -W bulk-memory=y -W threads=y -S threads=y --"
+          RUSTFLAGS: --cfg tokio_unstable -Dwarnings -C target-feature=+atomics,+bulk-memory -C link-args=--max-memory=67108864
 
       - name: WASI test tokio-stream
-        run: cargo test -p tokio-stream --target wasm32-wasi --features time,net,io-util,sync
+        run: cargo test -p tokio-stream --target ${{ matrix.target }} --features time,net,io-util,sync
         env:
           CARGO_TARGET_WASM32_WASI_RUNNER: "wasmtime run --"
-          RUSTFLAGS: --cfg tokio_unstable -Dwarnings
+          CARGO_TARGET_WASM32_WASI_PREVIEW1_THREADS_RUNNER: "wasmtime run -W bulk-memory=y -W threads=y -S threads=y --"
+          RUSTFLAGS: --cfg tokio_unstable -Dwarnings -C target-feature=+atomics,+bulk-memory -C link-args=--max-memory=67108864
 
       - name: test tests-integration --features wasi-rt
         # TODO: this should become: `cargo hack wasi test --each-feature`
         run: cargo wasi test --test rt_yield --features wasi-rt
+        if: matrix.target == 'wasm32-wasi'
+        working-directory: tests-integration
+
+      - name: test tests-integration --features wasi-threads-rt
+        run: cargo test --target ${{ matrix.target }} --features wasi-threads-rt
+        if: matrix.target == 'wasm32-wasi-preview1-threads'
         working-directory: tests-integration
+        env:
+          CARGO_TARGET_WASM32_WASI_PREVIEW1_THREADS_RUNNER: "wasmtime run -W bulk-memory=y -W threads=y -S threads=y --"
+          RUSTFLAGS: --cfg tokio_unstable -Dwarnings -C target-feature=+atomics,+bulk-memory -C link-args=--max-memory=67108864
 
   check-external-types:
     name: check-external-types (${{ matrix.os }})

tests-integration/Cargo.toml

@@ -39,6 +39,7 @@ rt-process-signal = ["rt-net", "tokio/process", "tokio/signal"]
 # This is an explicit feature so we can use `cargo hack` testing single features
 # instead of all possible permutations.
 wasi-rt = ["rt", "macros", "sync"]
+wasi-threads-rt = ["wasi-rt", "rt-multi-thread"]
 
 full = [
     "macros",

tests-integration/tests/macros_main.rs

@@ -1,8 +1,4 @@
-#![cfg(all(
-    feature = "macros",
-    feature = "rt-multi-thread",
-    not(target_os = "wasi")
-))]
+#![cfg(all(feature = "macros", feature = "rt-multi-thread"))]
 
 #[tokio::main]
 async fn basic_main() -> usize {

tests-integration/tests/macros_select.rs

@@ -4,7 +4,10 @@ use futures::channel::oneshot;
 use futures::executor::block_on;
 use std::thread;
 
-#[cfg_attr(target_os = "wasi", ignore = "WASI: std::thread::spawn not supported")]
+#[cfg_attr(
+    not(feature = "rt-multi-thread"),
+    ignore = "WASI: std::thread::spawn not supported"
+)]
 #[test]
 fn join_with_select() {
     block_on(async {

tokio-util/src/task/mod.rs

@@ -2,9 +2,7 @@
 
 #[cfg(tokio_unstable)]
 mod join_map;
-#[cfg(not(target_os = "wasi"))]
 mod spawn_pinned;
-#[cfg(not(target_os = "wasi"))]
 pub use spawn_pinned::LocalPoolHandle;
 
 #[cfg(tokio_unstable)]

tokio/src/macros/cfg.rs

@@ -384,7 +384,7 @@ macro_rules! cfg_not_rt {
 macro_rules! cfg_rt_multi_thread {
     ($($item:item)*) => {
         $(
-            #[cfg(all(feature = "rt-multi-thread", not(target_os = "wasi")))]
+            #[cfg(feature = "rt-multi-thread")]
             #[cfg_attr(docsrs, doc(cfg(feature = "rt-multi-thread")))]
             $item
         )*

tokio/src/runtime/blocking/schedule.rs

@@ -23,9 +23,9 @@ impl BlockingSchedule {
                 scheduler::Handle::CurrentThread(handle) => {
                     handle.driver.clock.inhibit_auto_advance();
                 }
-                #[cfg(all(feature = "rt-multi-thread", not(target_os = "wasi")))]
+                #[cfg(feature = "rt-multi-thread")]
                 scheduler::Handle::MultiThread(_) => {}
-                #[cfg(all(tokio_unstable, feature = "rt-multi-thread", not(target_os = "wasi")))]
+                #[cfg(all(tokio_unstable, feature = "rt-multi-thread"))]
                 scheduler::Handle::MultiThreadAlt(_) => {}
             }
         }
@@ -45,9 +45,9 @@ impl task::Schedule for BlockingSchedule {
                     handle.driver.clock.allow_auto_advance();
                     handle.driver.unpark();
                 }
-                #[cfg(all(feature = "rt-multi-thread", not(target_os = "wasi")))]
+                #[cfg(feature = "rt-multi-thread")]
                 scheduler::Handle::MultiThread(_) => {}
-                #[cfg(all(tokio_unstable, feature = "rt-multi-thread", not(target_os = "wasi")))]
+                #[cfg(all(tokio_unstable, feature = "rt-multi-thread"))]
                 scheduler::Handle::MultiThreadAlt(_) => {}
             }
         }

tokio/src/runtime/builder.rs

@@ -199,9 +199,9 @@ pub(crate) type ThreadNameFn = std::sync::Arc<dyn Fn() -> String + Send + Sync +
 #[derive(Clone, Copy)]
 pub(crate) enum Kind {
     CurrentThread,
-    #[cfg(all(feature = "rt-multi-thread", not(target_os = "wasi")))]
+    #[cfg(feature = "rt-multi-thread")]
     MultiThread,
-    #[cfg(all(tokio_unstable, feature = "rt-multi-thread", not(target_os = "wasi")))]
+    #[cfg(all(tokio_unstable, feature = "rt-multi-thread"))]
     MultiThreadAlt,
 }
 
@@ -224,35 +224,33 @@ impl Builder {
         Builder::new(Kind::CurrentThread, EVENT_INTERVAL)
     }
 
-    cfg_not_wasi! {
-        /// Returns a new builder with the multi thread scheduler selected.
+    /// Returns a new builder with the multi thread scheduler selected.
+    ///
+    /// Configuration methods can be chained on the return value.
+    #[cfg(feature = "rt-multi-thread")]
+    #[cfg_attr(docsrs, doc(cfg(feature = "rt-multi-thread")))]
+    pub fn new_multi_thread() -> Builder {
+        // The number `61` is fairly arbitrary. I believe this value was copied from golang.
+        Builder::new(Kind::MultiThread, 61)
+    }
+
+    cfg_unstable! {
+        /// Returns a new builder with the alternate multi thread scheduler
+        /// selected.
+        ///
+        /// The alternate multi threaded scheduler is an in-progress
+        /// candidate to replace the existing multi threaded scheduler. It
+        /// currently does not scale as well to 16+ processors.
+        ///
+        /// This runtime flavor is currently **not considered production
+        /// ready**.
         ///
         /// Configuration methods can be chained on the return value.
         #[cfg(feature = "rt-multi-thread")]
         #[cfg_attr(docsrs, doc(cfg(feature = "rt-multi-thread")))]
-        pub fn new_multi_thread() -> Builder {
+        pub fn new_multi_thread_alt() -> Builder {
             // The number `61` is fairly arbitrary. I believe this value was copied from golang.
-            Builder::new(Kind::MultiThread, 61)
-        }
-
-        cfg_unstable! {
-            /// Returns a new builder with the alternate multi thread scheduler
-            /// selected.
-            ///
-            /// The alternate multi threaded scheduler is an in-progress
-            /// candidate to replace the existing multi threaded scheduler. It
-            /// currently does not scale as well to 16+ processors.
-            ///
-            /// This runtime flavor is currently **not considered production
-            /// ready**.
-            ///
-            /// Configuration methods can be chained on the return value.
-            #[cfg(feature = "rt-multi-thread")]
-            #[cfg_attr(docsrs, doc(cfg(feature = "rt-multi-thread")))]
-            pub fn new_multi_thread_alt() -> Builder {
-                // The number `61` is fairly arbitrary. I believe this value was copied from golang.
-                Builder::new(Kind::MultiThreadAlt, 61)
-            }
+            Builder::new(Kind::MultiThreadAlt, 61)
         }
     }
 
@@ -697,9 +695,9 @@ impl Builder {
     pub fn build(&mut self) -> io::Result<Runtime> {
         match &self.kind {
             Kind::CurrentThread => self.build_current_thread_runtime(),
-            #[cfg(all(feature = "rt-multi-thread", not(target_os = "wasi")))]
+            #[cfg(feature = "rt-multi-thread")]
             Kind::MultiThread => self.build_threaded_runtime(),
-            #[cfg(all(tokio_unstable, feature = "rt-multi-thread", not(target_os = "wasi")))]
+            #[cfg(all(tokio_unstable, feature = "rt-multi-thread"))]
             Kind::MultiThreadAlt => self.build_alt_threaded_runtime(),
         }
     }
@@ -708,9 +706,9 @@ impl Builder {
         driver::Cfg {
             enable_pause_time: match self.kind {
                 Kind::CurrentThread => true,
-                #[cfg(all(feature = "rt-multi-thread", not(target_os = "wasi")))]
+                #[cfg(feature = "rt-multi-thread")]
                 Kind::MultiThread => false,
-                #[cfg(all(tokio_unstable, feature = "rt-multi-thread", not(target_os = "wasi")))]
+                #[cfg(all(tokio_unstable, feature = "rt-multi-thread"))]
                 Kind::MultiThreadAlt => false,
             },
             enable_io: self.enable_io,

tokio/src/runtime/handle.rs

@@ -355,9 +355,9 @@ impl Handle {
     pub fn runtime_flavor(&self) -> RuntimeFlavor {
         match self.inner {
             scheduler::Handle::CurrentThread(_) => RuntimeFlavor::CurrentThread,
-            #[cfg(all(feature = "rt-multi-thread", not(target_os = "wasi")))]
+            #[cfg(feature = "rt-multi-thread")]
             scheduler::Handle::MultiThread(_) => RuntimeFlavor::MultiThread,
-            #[cfg(all(tokio_unstable, feature = "rt-multi-thread", not(target_os = "wasi")))]
+            #[cfg(all(tokio_unstable, feature = "rt-multi-thread"))]
             scheduler::Handle::MultiThreadAlt(_) => RuntimeFlavor::MultiThreadAlt,
         }
     }
@@ -385,9 +385,9 @@ impl Handle {
         pub fn id(&self) -> runtime::Id {
             let owned_id = match &self.inner {
                 scheduler::Handle::CurrentThread(handle) => handle.owned_id(),
-                #[cfg(all(feature = "rt-multi-thread", not(target_os = "wasi")))]
+                #[cfg(feature = "rt-multi-thread")]
                 scheduler::Handle::MultiThread(handle) => handle.owned_id(),
-                #[cfg(all(tokio_unstable, feature = "rt-multi-thread", not(target_os = "wasi")))]
+                #[cfg(all(tokio_unstable, feature = "rt-multi-thread"))]
                 scheduler::Handle::MultiThreadAlt(handle) => handle.owned_id(),
             };
             owned_id.into()

tokio/src/runtime/runtime.rs

@@ -126,11 +126,11 @@ pub(super) enum Scheduler {
     CurrentThread(CurrentThread),
 
     /// Execute tasks across multiple threads.
-    #[cfg(all(feature = "rt-multi-thread", not(target_os = "wasi")))]
+    #[cfg(feature = "rt-multi-thread")]
     MultiThread(MultiThread),
 
     /// Execute tasks across multiple threads.
-    #[cfg(all(tokio_unstable, feature = "rt-multi-thread", not(target_os = "wasi")))]
+    #[cfg(all(tokio_unstable, feature = "rt-multi-thread"))]
     MultiThreadAlt(MultiThreadAlt),
 }
 
@@ -147,40 +147,38 @@ impl Runtime {
         }
     }
 
-    cfg_not_wasi! {
-        /// Creates a new runtime instance with default configuration values.
-        ///
-        /// This results in the multi threaded scheduler, I/O driver, and time driver being
-        /// initialized.
-        ///
-        /// Most applications will not need to call this function directly. Instead,
-        /// they will use the  [`#[tokio::main]` attribute][main]. When a more complex
-        /// configuration is necessary, the [runtime builder] may be used.
-        ///
-        /// See [module level][mod] documentation for more details.
-        ///
-        /// # Examples
-        ///
-        /// Creating a new `Runtime` with default configuration values.
-        ///
-        /// ```
-        /// use tokio::runtime::Runtime;
-        ///
-        /// let rt = Runtime::new()
-        ///     .unwrap();
-        ///
-        /// // Use the runtime...
-        /// ```
-        ///
-        /// [mod]: index.html
-        /// [main]: ../attr.main.html
-        /// [threaded scheduler]: index.html#threaded-scheduler
-        /// [runtime builder]: crate::runtime::Builder
-        #[cfg(feature = "rt-multi-thread")]
-        #[cfg_attr(docsrs, doc(cfg(feature = "rt-multi-thread")))]
-        pub fn new() -> std::io::Result<Runtime> {
-            Builder::new_multi_thread().enable_all().build()
-        }
+    /// Creates a new runtime instance with default configuration values.
+    ///
+    /// This results in the multi threaded scheduler, I/O driver, and time driver being
+    /// initialized.
+    ///
+    /// Most applications will not need to call this function directly. Instead,
+    /// they will use the  [`#[tokio::main]` attribute][main]. When a more complex
+    /// configuration is necessary, the [runtime builder] may be used.
+    ///
+    /// See [module level][mod] documentation for more details.
+    ///
+    /// # Examples
+    ///
+    /// Creating a new `Runtime` with default configuration values.
+    ///
+    /// ```
+    /// use tokio::runtime::Runtime;
+    ///
+    /// let rt = Runtime::new()
+    ///     .unwrap();
+    ///
+    /// // Use the runtime...
+    /// ```
+    ///
+    /// [mod]: index.html
+    /// [main]: ../attr.main.html
+    /// [threaded scheduler]: index.html#threaded-scheduler
+    /// [runtime builder]: crate::runtime::Builder
+    #[cfg(feature = "rt-multi-thread")]
+    #[cfg_attr(docsrs, doc(cfg(feature = "rt-multi-thread")))]
+    pub fn new() -> std::io::Result<Runtime> {
+        Builder::new_multi_thread().enable_all().build()
     }
 
     /// Returns a handle to the runtime's spawner.
@@ -347,9 +345,9 @@ impl Runtime {
 
         match &self.scheduler {
             Scheduler::CurrentThread(exec) => exec.block_on(&self.handle.inner, future),
-            #[cfg(all(feature = "rt-multi-thread", not(target_os = "wasi")))]
+            #[cfg(feature = "rt-multi-thread")]
             Scheduler::MultiThread(exec) => exec.block_on(&self.handle.inner, future),
-            #[cfg(all(tokio_unstable, feature = "rt-multi-thread", not(target_os = "wasi")))]
+            #[cfg(all(tokio_unstable, feature = "rt-multi-thread"))]
             Scheduler::MultiThreadAlt(exec) => exec.block_on(&self.handle.inner, future),
         }
     }
@@ -469,13 +467,13 @@ impl Drop for Runtime {
                 let _guard = context::try_set_current(&self.handle.inner);
                 current_thread.shutdown(&self.handle.inner);
             }
-            #[cfg(all(feature = "rt-multi-thread", not(target_os = "wasi")))]
+            #[cfg(feature = "rt-multi-thread")]
             Scheduler::MultiThread(multi_thread) => {
                 // The threaded scheduler drops its tasks on its worker threads, which is
                 // already in the runtime's context.
                 multi_thread.shutdown(&self.handle.inner);
             }
-            #[cfg(all(tokio_unstable, feature = "rt-multi-thread", not(target_os = "wasi")))]
+            #[cfg(all(tokio_unstable, feature = "rt-multi-thread"))]
             Scheduler::MultiThreadAlt(multi_thread) => {
                 // The threaded scheduler drops its tasks on its worker threads, which is
                 // already in the runtime's context.

tokio/src/runtime/scheduler/inject/shared.rs

@@ -38,10 +38,7 @@ impl<T: 'static> Shared<T> {
     }
 
     // Kind of annoying to have to include the cfg here
-    #[cfg(any(
-        tokio_taskdump,
-        all(feature = "rt-multi-thread", not(target_os = "wasi"))
-    ))]
+    #[cfg(any(tokio_taskdump, feature = "rt-multi-thread"))]
     pub(crate) fn is_closed(&self, synced: &Synced) -> bool {
         synced.is_closed
     }