Implement co-op threading builtins (#2298)

* Implement co-op threading builtins

* Change content.get/set validation

* Change content.get/set validation

* Improve context immediate validation

* Update thread.new_indirect approach

* Refactor import name validation and extraction

* Split features

Author: TartanLlama

crates/wasm-encoder/src/component/builder.rs

@@ -425,9 +425,9 @@ impl ComponentBuilder {
         inc(&mut self.core_funcs)
     }
 
-    /// Declares a new `task.yield` intrinsic.
-    pub fn yield_(&mut self, async_: bool) -> u32 {
-        self.canonical_functions().yield_(async_);
+    /// Declares a new `thread.yield` intrinsic.
+    pub fn thread_yield(&mut self, cancellable: bool) -> u32 {
+        self.canonical_functions().thread_yield(cancellable);
         inc(&mut self.core_funcs)
     }
 
@@ -577,14 +577,16 @@ impl ComponentBuilder {
     }
 
     /// Declares a new `waitable-set.wait` intrinsic.
-    pub fn waitable_set_wait(&mut self, async_: bool, memory: u32) -> u32 {
-        self.canonical_functions().waitable_set_wait(async_, memory);
+    pub fn waitable_set_wait(&mut self, cancellable: bool, memory: u32) -> u32 {
+        self.canonical_functions()
+            .waitable_set_wait(cancellable, memory);
         inc(&mut self.core_funcs)
     }
 
     /// Declares a new `waitable-set.poll` intrinsic.
-    pub fn waitable_set_poll(&mut self, async_: bool, memory: u32) -> u32 {
-        self.canonical_functions().waitable_set_poll(async_, memory);
+    pub fn waitable_set_poll(&mut self, cancellable: bool, memory: u32) -> u32 {
+        self.canonical_functions()
+            .waitable_set_poll(cancellable, memory);
         inc(&mut self.core_funcs)
     }
 
@@ -600,6 +602,43 @@ impl ComponentBuilder {
         inc(&mut self.core_funcs)
     }
 
+    /// Declares a new `thread.index` intrinsic.
+    pub fn thread_index(&mut self) -> u32 {
+        self.canonical_functions().thread_index();
+        inc(&mut self.core_funcs)
+    }
+
+    /// Declares a new `thread.new_indirect` intrinsic.
+    pub fn thread_new_indirect(&mut self, func_ty_idx: u32, table_index: u32) -> u32 {
+        self.canonical_functions()
+            .thread_new_indirect(func_ty_idx, table_index);
+        inc(&mut self.core_funcs)
+    }
+
+    /// Declares a new `thread.switch-to` intrinsic.
+    pub fn thread_switch_to(&mut self, cancellable: bool) -> u32 {
+        self.canonical_functions().thread_switch_to(cancellable);
+        inc(&mut self.core_funcs)
+    }
+
+    /// Declares a new `thread.suspend` intrinsic.
+    pub fn thread_suspend(&mut self, cancellable: bool) -> u32 {
+        self.canonical_functions().thread_suspend(cancellable);
+        inc(&mut self.core_funcs)
+    }
+
+    /// Declares a new `thread.resume-later` intrinsic.
+    pub fn thread_resume_later(&mut self) -> u32 {
+        self.canonical_functions().thread_resume_later();
+        inc(&mut self.core_funcs)
+    }
+
+    /// Declares a new `thread.yield-to` intrinsic.
+    pub fn thread_yield_to(&mut self, cancellable: bool) -> u32 {
+        self.canonical_functions().thread_yield_to(cancellable);
+        inc(&mut self.core_funcs)
+    }
+
     /// Adds a new custom section to this component.
     pub fn custom_section(&mut self, section: &CustomSection<'_>) {
         self.flush();

crates/wasm-encoder/src/component/canonicals.rs

@@ -249,10 +249,10 @@ impl CanonicalFunctionSection {
     /// Defines a function which yields control to the host so that other tasks
     /// are able to make progress, if any.
     ///
-    /// If `async_` is true, the caller instance may be reentered.
-    pub fn yield_(&mut self, async_: bool) -> &mut Self {
+    /// If `cancellable` is true, the caller instance may be reentered.
+    pub fn thread_yield(&mut self, cancellable: bool) -> &mut Self {
         self.bytes.push(0x0c);
-        self.bytes.push(if async_ { 1 } else { 0 });
+        self.bytes.push(if cancellable { 1 } else { 0 });
         self.num_added += 1;
         self
     }
@@ -498,6 +498,59 @@ impl CanonicalFunctionSection {
         self
     }
 
+    /// Declare a new `thread.index` intrinsic, used to get the index of the
+    /// current thread.
+    pub fn thread_index(&mut self) -> &mut Self {
+        self.bytes.push(0x26);
+        self.num_added += 1;
+        self
+    }
+
+    /// Declare a new `thread.new_indirect` intrinsic, used to create a new
+    /// thread by invoking a function indirectly through a `funcref` table.
+    pub fn thread_new_indirect(&mut self, ty_index: u32, table_index: u32) -> &mut Self {
+        self.bytes.push(0x27);
+        ty_index.encode(&mut self.bytes);
+        table_index.encode(&mut self.bytes);
+        self.num_added += 1;
+        self
+    }
+
+    /// Declare a new `thread.switch-to` intrinsic, used to switch execution to
+    /// another thread.
+    pub fn thread_switch_to(&mut self, cancellable: bool) -> &mut Self {
+        self.bytes.push(0x28);
+        self.bytes.push(if cancellable { 1 } else { 0 });
+        self.num_added += 1;
+        self
+    }
+
+    /// Declare a new `thread.suspend` intrinsic, used to suspend execution of
+    /// the current thread.
+    pub fn thread_suspend(&mut self, cancellable: bool) -> &mut Self {
+        self.bytes.push(0x29);
+        self.bytes.push(if cancellable { 1 } else { 0 });
+        self.num_added += 1;
+        self
+    }
+
+    /// Declare a new `thread.resume-later` intrinsic, used to resume execution
+    /// of the given thread.
+    pub fn thread_resume_later(&mut self) -> &mut Self {
+        self.bytes.push(0x2a);
+        self.num_added += 1;
+        self
+    }
+
+    /// Declare a new `thread.yield-to` intrinsic, used to yield execution to
+    /// a given thread.
+    pub fn thread_yield_to(&mut self, cancellable: bool) -> &mut Self {
+        self.bytes.push(0x2b);
+        self.bytes.push(if cancellable { 1 } else { 0 });
+        self.num_added += 1;
+        self
+    }
+
     fn encode_options<O>(&mut self, options: O) -> &mut Self
     where
         O: IntoIterator<Item = CanonicalOption>,

crates/wasm-encoder/src/reencode/component.rs

@@ -995,8 +995,8 @@ pub mod component_utils {
             wasmparser::CanonicalFunction::ContextSet(i) => {
                 section.context_set(i);
             }
-            wasmparser::CanonicalFunction::Yield { async_ } => {
-                section.yield_(async_);
+            wasmparser::CanonicalFunction::ThreadYield { cancellable } => {
+                section.thread_yield(cancellable);
             }
             wasmparser::CanonicalFunction::SubtaskDrop => {
                 section.subtask_drop();
@@ -1082,18 +1082,47 @@ pub mod component_utils {
             wasmparser::CanonicalFunction::WaitableSetNew => {
                 section.waitable_set_new();
             }
-            wasmparser::CanonicalFunction::WaitableSetWait { async_, memory } => {
-                section.waitable_set_wait(async_, reencoder.memory_index(memory)?);
+            wasmparser::CanonicalFunction::WaitableSetWait {
+                cancellable,
+                memory,
+            } => {
+                section.waitable_set_wait(cancellable, reencoder.memory_index(memory)?);
             }
-            wasmparser::CanonicalFunction::WaitableSetPoll { async_, memory } => {
-                section.waitable_set_poll(async_, reencoder.memory_index(memory)?);
+            wasmparser::CanonicalFunction::WaitableSetPoll {
+                cancellable,
+                memory,
+            } => {
+                section.waitable_set_poll(cancellable, reencoder.memory_index(memory)?);
             }
             wasmparser::CanonicalFunction::WaitableSetDrop => {
                 section.waitable_set_drop();
             }
             wasmparser::CanonicalFunction::WaitableJoin => {
                 section.waitable_join();
             }
+            wasmparser::CanonicalFunction::ThreadIndex => {
+                section.thread_index();
+            }
+            wasmparser::CanonicalFunction::ThreadNewIndirect {
+                func_ty_index,
+                table_index,
+            } => {
+                let func_ty = reencoder.type_index(func_ty_index)?;
+                let table_index = reencoder.table_index(table_index)?;
+                section.thread_new_indirect(func_ty, table_index);
+            }
+            wasmparser::CanonicalFunction::ThreadSwitchTo { cancellable } => {
+                section.thread_switch_to(cancellable);
+            }
+            wasmparser::CanonicalFunction::ThreadSuspend { cancellable } => {
+                section.thread_suspend(cancellable);
+            }
+            wasmparser::CanonicalFunction::ThreadResumeLater => {
+                section.thread_resume_later();
+            }
+            wasmparser::CanonicalFunction::ThreadYieldTo { cancellable } => {
+                section.thread_yield_to(cancellable);
+            }
         }
         Ok(())
     }

crates/wasmparser/src/features.rs

@@ -265,36 +265,41 @@ define_wasm_features! {
         /// Corresponds to the 🚝 character in
         /// <https://github.com/WebAssembly/component-model/blob/main/design/mvp/Explainer.md>.
         pub cm_async_builtins: CM_ASYNC_BUILTINS(1 << 29) = false;
+        /// Support for threading in the component model proposal.
+        ///
+        /// Corresponds to the 🧵 character in
+        /// <https://github.com/WebAssembly/component-model/blob/main/design/mvp/Explainer.md>.
+        pub cm_threading: CM_THREADING(1 << 30) = false;
         /// Gates some intrinsics being marked with `error-context` in the component
         /// model async proposal.
         ///
         /// Corresponds to the 📝 character in
         /// <https://github.com/WebAssembly/component-model/blob/main/design/mvp/Explainer.md>.
-        pub cm_error_context: CM_ERROR_CONTEXT(1 << 30) = false;
+        pub cm_error_context: CM_ERROR_CONTEXT(1 << 31) = false;
         /// Support for fixed size lists
         ///
         /// Corresponds to the 🔧 character in
         /// <https://github.com/WebAssembly/component-model/blob/main/design/mvp/Explainer.md>.
-        pub cm_fixed_size_list: CM_FIXED_SIZE_LIST(1 << 31) = false;
+        pub cm_fixed_size_list: CM_FIXED_SIZE_LIST(1 << 32) = false;
         /// Support for Wasm GC in the component model proposal.
         ///
         /// Corresponds to the 🛸 character in
         /// <https://github.com/WebAssembly/component-model/blob/main/design/mvp/Explainer.md>.
-        pub cm_gc: CM_GC(1 << 32) = false;
+        pub cm_gc: CM_GC(1 << 33) = false;
 
         /// Subset of the reference-types WebAssembly proposal which only
         /// encompasses the leb-encoding of the table immediate to the
         /// `call_indirect` instruction, enabling over-long encodings of an
         /// integer for example.
         ///
         /// This is a subcomponent of the "lime1" feature.
-        pub call_indirect_overlong: CALL_INDIRECT_OVERLONG(1 << 33) = true;
+        pub call_indirect_overlong: CALL_INDIRECT_OVERLONG(1 << 34) = true;
 
         /// Subset of the bulk-memory proposal covering just the `memory.copy`
         /// and `memory.fill` instructions.
         ///
         /// This is a subcomponent of the "lime1" feature.
-        pub bulk_memory_opt: BULK_MEMORY_OPT(1 << 34) = true;
+        pub bulk_memory_opt: BULK_MEMORY_OPT(1 << 35) = true;
     }
 }
 

crates/wasmparser/src/readers/component/canonicals.rs

@@ -110,9 +110,9 @@ pub enum CanonicalFunction {
     ContextSet(u32),
     /// A function which yields control to the host so that other tasks are able
     /// to make progress, if any.
-    Yield {
+    ThreadYield {
         /// If `true`, indicates the caller instance maybe reentered.
-        async_: bool,
+        cancellable: bool,
     },
     /// A function to drop a specified task which has completed.
     SubtaskDrop,
@@ -246,22 +246,48 @@ pub enum CanonicalFunction {
     WaitableSetWait {
         /// Whether or not the guest can be reentered while calling this
         /// function.
-        async_: bool,
+        cancellable: bool,
         /// Which memory the results of this operation are stored in.
         memory: u32,
     },
     /// A function to check if any items are ready within a `waitable-set`.
     WaitableSetPoll {
         /// Whether or not the guest can be reentered while calling this
         /// function.
-        async_: bool,
+        cancellable: bool,
         /// Which memory the results of this operation are stored in.
         memory: u32,
     },
     /// A function to drop a `waitable-set`.
     WaitableSetDrop,
     /// A function to add an item to a `waitable-set`.
     WaitableJoin,
+    /// A function to get the index of the current thread.
+    ThreadIndex,
+    /// A function to create a new thread with the specified start function.
+    ThreadNewIndirect {
+        /// The index of the function type to use as the start function.
+        func_ty_index: u32,
+        /// The index of the table to use.
+        table_index: u32,
+    },
+    /// A function to suspend the current thread and switch to the given thread.
+    ThreadSwitchTo {
+        /// Whether or not the thread can be cancelled while awaiting resumption.
+        cancellable: bool,
+    },
+    /// A function to suspend the current thread, immediately yielding to any transitive async-lowered calling component.
+    ThreadSuspend {
+        /// Whether or not the thread can be cancelled while suspended.
+        cancellable: bool,
+    },
+    /// A function to schedule the given thread to be resumed later.
+    ThreadResumeLater,
+    /// A function to suspend the current thread and switch to the given thread.
+    ThreadYieldTo {
+        /// Whether or not the thread can be cancelled while yielding.
+        cancellable: bool,
+    },
 }
 
 /// A reader for the canonical section of a WebAssembly component.
@@ -310,8 +336,8 @@ impl<'a> FromReader<'a> for CanonicalFunction {
                 0x7f => CanonicalFunction::ContextSet(reader.read_var_u32()?),
                 x => return reader.invalid_leading_byte(x, "context.set intrinsic type"),
             },
-            0x0c => CanonicalFunction::Yield {
-                async_: reader.read()?,
+            0x0c => CanonicalFunction::ThreadYield {
+                cancellable: reader.read()?,
             },
             0x0d => CanonicalFunction::SubtaskDrop,
             0x0e => CanonicalFunction::StreamNew { ty: reader.read()? },
@@ -362,15 +388,30 @@ impl<'a> FromReader<'a> for CanonicalFunction {
 
             0x1f => CanonicalFunction::WaitableSetNew,
             0x20 => CanonicalFunction::WaitableSetWait {
-                async_: reader.read()?,
+                cancellable: reader.read()?,
                 memory: reader.read()?,
             },
             0x21 => CanonicalFunction::WaitableSetPoll {
-                async_: reader.read()?,
+                cancellable: reader.read()?,
                 memory: reader.read()?,
             },
             0x22 => CanonicalFunction::WaitableSetDrop,
             0x23 => CanonicalFunction::WaitableJoin,
+            0x26 => CanonicalFunction::ThreadIndex,
+            0x27 => CanonicalFunction::ThreadNewIndirect {
+                func_ty_index: reader.read()?,
+                table_index: reader.read()?,
+            },
+            0x28 => CanonicalFunction::ThreadSwitchTo {
+                cancellable: reader.read()?,
+            },
+            0x29 => CanonicalFunction::ThreadSuspend {
+                cancellable: reader.read()?,
+            },
+            0x2a => CanonicalFunction::ThreadResumeLater,
+            0x2b => CanonicalFunction::ThreadYieldTo {
+                cancellable: reader.read()?,
+            },
             0x06 => CanonicalFunction::SubtaskCancel {
                 async_: reader.read()?,
             },