runtime: make channels parallelism-safe

src/internal/task/task.go

@@ -27,7 +27,7 @@ type Task struct {
 }
 
 // DataUint32 returns the Data field as a uint32. The value is only valid after
-// setting it through SetDataUint32.
+// setting it through SetDataUint32 or by storing to it using DataAtomicUint32.
 func (t *Task) DataUint32() uint32 {
 	return *(*uint32)(unsafe.Pointer(&t.Data))
 }
@@ -38,6 +38,11 @@ func (t *Task) SetDataUint32(val uint32) {
 	*(*uint32)(unsafe.Pointer(&t.Data)) = val
 }
 
+// DataAtomicUint32 returns the Data field as an atomic-if-needed Uint32 value.
+func (t *Task) DataAtomicUint32() *Uint32 {
+	return (*Uint32)(unsafe.Pointer(&t.Data))
+}
+
 // getGoroutineStackSize is a compiler intrinsic that returns the stack size for
 // the given function and falls back to the default stack size. It is replaced
 // with a load from a special section just before codegen.