[vm] Allow sending closures between isolates of the same isolate group

Closures can be shared if they have no state they capture (i.e. a null
context). Otherwise we copy them by also transitively copying the
parent context chain.

Issue https://github.com/dart-lang/sdk/issues/36097

TEST=Added tests to vm/dart{,_2}/isolates/fast_object_copy{,2}_test

Change-Id: Ie641b97806edd0c21f0a8d5c514f8e850823e165
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/209110
Commit-Queue: Martin Kustermann <kustermann@google.com>
Reviewed-by: Alexander Aprelev <aam@google.com>
Reviewed-by: Ryan Macnak <rmacnak@google.com>

runtime/tests/vm/dart/isolates/fast_object_copy2_test.dart

@@ -19,6 +19,14 @@ import 'package:expect/expect.dart';
 import 'fast_object_copy_test.dart'
     show UserObject, SendReceiveTestBase, notAllocatableInTLAB;
 
+topLevelClosure(a, b) {}
+topLevelClosureG<T>(T a, T b) {}
+Type getType<T>() => T;
+
+class A<T> {
+  dynamic m<H>(T a, H b) => this;
+}
+
 // When running with isolate groups enabled, we can share all of the following
 // objects.
 final sharableObjects = [
@@ -32,6 +40,36 @@ final sharableObjects = [
     rp.close();
     return sp;
   })(),
+  () {
+    innerClosure(a, b) {}
+    return innerClosure;
+  }(),
+  () {
+    innerClosureG<T>(T a, T b) {}
+    return innerClosureG;
+  }(),
+  () {
+    innerClosureG<T>() {
+      innerClosureG2<H>(T a, H b) {}
+      return innerClosureG2;
+    }
+
+    return innerClosureG<int>();
+  }(),
+  () {
+    innerClosureG<T>(T a, T b) {}
+    final Function(int, int) partialInstantiatedInnerClosure = innerClosureG;
+    return partialInstantiatedInnerClosure;
+  }(),
+  () {
+    return topLevelClosureG;
+  }(),
+  () {
+    final Function(int, int) partialInstantiatedInnerClosure = topLevelClosureG;
+    return partialInstantiatedInnerClosure;
+  }(),
+  getType<void Function(int, double, Object)>(),
+  getType<T Function<T>(int, double, T)>(),
   const [1, 2, 3],
   const {1: 1, 2: 2, 3: 2},
   const {1, 2, 3},
@@ -40,13 +78,40 @@ final sharableObjects = [
   Int32x4(1, 2, 3, 4),
 ];
 
+final copyableClosures = <dynamic>[
+  () {
+    final a = A<int>();
+    final Function<T>(int, T) genericMethod = a.m;
+    return genericMethod;
+  }(),
+  () {
+    final a = A<int>();
+    final Function(int, double) partialInstantiatedMethod = a.m;
+    return partialInstantiatedMethod;
+  }(),
+  () {
+    final a = Object();
+    dynamic inner() => a;
+    return inner;
+  }(),
+  () {
+    foo(var arg) {
+      return () => arg;
+    }
+
+    return foo(1);
+  }(),
+];
+
 class SendReceiveTest extends SendReceiveTestBase {
   Future runTests() async {
     await testSharable();
     await testSharable2();
+    await testCopyableClosures();
   }
 
   Future testSharable() async {
+    print('testSharable');
     final sharableObjectsCopy = await sendReceive([
       ...sharableObjects,
     ]);
@@ -57,6 +122,7 @@ class SendReceiveTest extends SendReceiveTestBase {
   }
 
   Future testSharable2() async {
+    print('testSharable2');
     final sharableObjectsCopy = await sendReceive([
       notAllocatableInTLAB,
       ...sharableObjects,
@@ -68,6 +134,27 @@ class SendReceiveTest extends SendReceiveTestBase {
       Expect.identical(sharableObjects[i], sharableObjectsCopy[i + 1]);
     }
   }
+
+  Future testCopyableClosures() async {
+    print('testCopyableClosures');
+    final copy = await sendReceive([
+      notAllocatableInTLAB,
+      ...copyableClosures,
+    ]);
+    for (int i = 0; i < copyableClosures.length; ++i) {
+      Expect.notIdentical(copyableClosures[i], copy[1 + i]);
+      Expect.equals(copyableClosures[i].runtimeType, copy[1 + i].runtimeType);
+    }
+
+    final copy2 = await sendReceive([
+      ...copyableClosures,
+      notAllocatableInTLAB,
+    ]);
+    for (int i = 0; i < copyableClosures.length; ++i) {
+      Expect.notIdentical(copyableClosures[i], copy2[i]);
+      Expect.equals(copyableClosures[i].runtimeType, copy2[i].runtimeType);
+    }
+  }
 }
 
 main() async {

runtime/tests/vm/dart/isolates/fast_object_copy_test.dart

@@ -24,7 +24,9 @@ import 'dart:typed_data';
 
 import 'package:expect/expect.dart';
 
-class ClassWithNativeFields extends NativeFieldWrapperClass1 {}
+class ClassWithNativeFields extends NativeFieldWrapperClass1 {
+  void m() {}
+}
 
 final Uint8List largeExternalTypedData =
     File(Platform.resolvedExecutable).readAsBytesSync()..[0] = 42;
@@ -221,6 +223,8 @@ class SendReceiveTest extends SendReceiveTestBase {
     await testSlowOnly();
 
     await testWeakProperty();
+
+    await testForbiddenClosures();
   }
 
   Future testTransferrable() async {
@@ -644,6 +648,38 @@ class SendReceiveTest extends SendReceiveTestBase {
       Expect.equals('bar', (expando4Copy[expando4Copy] as Map)['foo']);
     }
   }
+
+  Future testForbiddenClosures() async {
+    print('testForbiddenClosures');
+    final nonCopyableClosures = <dynamic>[
+      (() {
+        final a = ClassWithNativeFields();
+        return a.m;
+      })(),
+      (() {
+        final a = ClassWithNativeFields();
+        dynamic inner() => a;
+        return inner;
+      })(),
+      (() {
+        foo(var arg) {
+          return () => arg;
+        }
+
+        return foo(ClassWithNativeFields());
+      })(),
+    ];
+    for (final closure in nonCopyableClosures) {
+      Expect.throwsArgumentError(() => sendPort.send(closure));
+    }
+    for (final closure in nonCopyableClosures) {
+      Expect.throwsArgumentError(() => sendPort.send([closure]));
+    }
+    for (final closure in nonCopyableClosures) {
+      Expect.throwsArgumentError(
+          () => sendPort.send([notAllocatableInTLAB, closure]));
+    }
+  }
 }
 
 main() async {

runtime/tests/vm/dart_2/isolates/fast_object_copy2_test.dart

@@ -21,6 +21,14 @@ import 'package:expect/expect.dart';
 import 'fast_object_copy_test.dart'
     show UserObject, SendReceiveTestBase, notAllocatableInTLAB;
 
+topLevelClosure(a, b) {}
+topLevelClosureG<T>(T a, T b) {}
+Type getType<T>() => T;
+
+class A<T> {
+  dynamic m<H>(T a, H b) => this;
+}
+
 // When running with isolate groups enabled, we can share all of the following
 // objects.
 final sharableObjects = [
@@ -34,6 +42,35 @@ final sharableObjects = [
     rp.close();
     return sp;
   })(),
+  () {
+    innerClosure(a, b) {}
+    return innerClosure;
+  }(),
+  () {
+    innerClosureG<T>(T a, T b) {}
+    return innerClosureG;
+  }(),
+  () {
+    innerClosureG<T>() {
+      innerClosureG2<H>(T a, H b) {}
+      return innerClosureG2;
+    }
+
+    return innerClosureG<int>();
+  }(),
+  () {
+    innerClosureG<T>(T a, T b) {}
+    final Function(int, int) partialInstantiatedInnerClosure = innerClosureG;
+    return partialInstantiatedInnerClosure;
+  }(),
+  () {
+    return topLevelClosureG;
+  }(),
+  () {
+    final Function(int, int) partialInstantiatedInnerClosure = topLevelClosureG;
+    return partialInstantiatedInnerClosure;
+  }(),
+  getType<void Function(int, double, Object)>(),
   const [1, 2, 3],
   const {1: 1, 2: 2, 3: 2},
   const {1, 2, 3},
@@ -42,13 +79,40 @@ final sharableObjects = [
   Int32x4(1, 2, 3, 4),
 ];
 
+final copyableClosures = <dynamic>[
+  () {
+    final a = A<int>();
+    final Function<T>(int, T) genericMethod = a.m;
+    return genericMethod;
+  }(),
+  () {
+    final a = A<int>();
+    final Function(int, double) partialInstantiatedMethod = a.m;
+    return partialInstantiatedMethod;
+  }(),
+  () {
+    final a = Object();
+    dynamic inner() => a;
+    return inner;
+  }(),
+  () {
+    foo(var arg) {
+      return () => arg;
+    }
+
+    return foo(1);
+  }(),
+];
+
 class SendReceiveTest extends SendReceiveTestBase {
   Future runTests() async {
     await testSharable();
     await testSharable2();
+    await testCopyableClosures();
   }
 
   Future testSharable() async {
+    print('testSharable');
     final sharableObjectsCopy = await sendReceive([
       ...sharableObjects,
     ]);
@@ -59,6 +123,7 @@ class SendReceiveTest extends SendReceiveTestBase {
   }
 
   Future testSharable2() async {
+    print('testSharable2');
     final sharableObjectsCopy = await sendReceive([
       notAllocatableInTLAB,
       ...sharableObjects,
@@ -70,6 +135,27 @@ class SendReceiveTest extends SendReceiveTestBase {
       Expect.identical(sharableObjects[i], sharableObjectsCopy[i + 1]);
     }
   }
+
+  Future testCopyableClosures() async {
+    print('testCopyableClosures');
+    final copy = await sendReceive([
+      notAllocatableInTLAB,
+      ...copyableClosures,
+    ]);
+    for (int i = 0; i < copyableClosures.length; ++i) {
+      Expect.notIdentical(copyableClosures[i], copy[1 + i]);
+      Expect.equals(copyableClosures[i].runtimeType, copy[1 + i].runtimeType);
+    }
+
+    final copy2 = await sendReceive([
+      ...copyableClosures,
+      notAllocatableInTLAB,
+    ]);
+    for (int i = 0; i < copyableClosures.length; ++i) {
+      Expect.notIdentical(copyableClosures[i], copy2[i]);
+      Expect.equals(copyableClosures[i].runtimeType, copy2[i].runtimeType);
+    }
+  }
 }
 
 main() async {

runtime/tests/vm/dart_2/isolates/fast_object_copy_test.dart

@@ -26,7 +26,9 @@ import 'dart:typed_data';
 
 import 'package:expect/expect.dart';
 
-class ClassWithNativeFields extends NativeFieldWrapperClass1 {}
+class ClassWithNativeFields extends NativeFieldWrapperClass1 {
+  void m() {}
+}
 
 final Uint8List largeExternalTypedData =
     File(Platform.resolvedExecutable).readAsBytesSync()..[0] = 42;
@@ -223,6 +225,8 @@ class SendReceiveTest extends SendReceiveTestBase {
     await testSlowOnly();
 
     await testWeakProperty();
+
+    await testForbiddenClosures();
   }
 
   Future testTransferrable() async {
@@ -646,6 +650,38 @@ class SendReceiveTest extends SendReceiveTestBase {
       Expect.equals('bar', (expando4Copy[expando4Copy] as Map)['foo']);
     }
   }
+
+  Future testForbiddenClosures() async {
+    print('testForbiddenClosures');
+    final nonCopyableClosures = <dynamic>[
+      (() {
+        final a = ClassWithNativeFields();
+        return a.m;
+      })(),
+      (() {
+        final a = ClassWithNativeFields();
+        dynamic inner() => a;
+        return inner;
+      })(),
+      (() {
+        foo(var arg) {
+          return () => arg;
+        }
+
+        return foo(ClassWithNativeFields());
+      })(),
+    ];
+    for (final closure in nonCopyableClosures) {
+      Expect.throwsArgumentError(() => sendPort.send(closure));
+    }
+    for (final closure in nonCopyableClosures) {
+      Expect.throwsArgumentError(() => sendPort.send([closure]));
+    }
+    for (final closure in nonCopyableClosures) {
+      Expect.throwsArgumentError(
+          () => sendPort.send([notAllocatableInTLAB, closure]));
+    }
+  }
 }
 
 main() async {

runtime/vm/message_snapshot.cc

@@ -3066,22 +3066,20 @@ void MessageSerializer::Trace(Object* object) {
   }
 
     ILLEGAL(FunctionType)
-    ILLEGAL(DynamicLibrary)
     ILLEGAL(MirrorReference)
-    ILLEGAL(Pointer)
     ILLEGAL(ReceivePort)
     ILLEGAL(StackTrace)
     ILLEGAL(UserTag)
-#undef ILLEGAL
 
-    switch (cid) {
-#define ILLEGAL(type) case kFfi##type##Cid:
-      CLASS_LIST_FFI(ILLEGAL)
+    // From "dart:ffi" we handle only Pointer/DynamicLibrary specially, since
+    // those are the only non-abstract classes (so we avoid checking more cids
+    // here that cannot happen in reality)
+    ILLEGAL(DynamicLibrary)
+    ILLEGAL(Pointer)
+    ILLEGAL(FfiDynamicLibrary)
+    ILLEGAL(FfiPointer)
+
 #undef ILLEGAL
-      IllegalObject(*object,
-                    "Native objects (from dart:ffi) such as Pointers and "
-                    "Structs cannot be passed between isolates.");
-    }
 
     if (cid >= kNumPredefinedCids || cid == kInstanceCid ||
         cid == kByteBufferCid) {

runtime/vm/object_graph_copy.cc

@@ -29,7 +29,6 @@
   V(Code)                                                                      \
   V(CodeSourceMap)                                                             \
   V(CompressedStackMaps)                                                       \
-  V(Context)                                                                   \
   V(ContextScope)                                                              \
   V(DynamicLibrary)                                                            \
   V(Error)                                                                     \
@@ -138,7 +137,7 @@ static ObjectPtr Marker() {
 }
 
 DART_FORCE_INLINE
-static bool CanShareObject(uword tags) {
+static bool CanShareObject(ObjectPtr obj, uword tags) {
   if ((tags & UntaggedObject::CanonicalBit::mask_in_place()) != 0) {
     return true;
   }
@@ -164,6 +163,11 @@ static bool CanShareObject(uword tags) {
   if (cid == kCapabilityCid) return true;
   if (cid == kRegExpCid) return true;
 
+  if (cid == kClosureCid) {
+    // We can share a closure iff it doesn't close over any state.
+    return Closure::RawCast(obj)->untag()->context() == Object::null();
+  }
+
   return false;
 }
 
@@ -259,6 +263,9 @@ void UpdateLengthField(intptr_t cid, ObjectPtr from, ObjectPtr to) {
   if (cid == kArrayCid) {
     static_cast<UntaggedArray*>(to.untag())->length_ =
         static_cast<UntaggedArray*>(from.untag())->length_;
+  } else if (cid == kContextCid) {
+    static_cast<UntaggedContext*>(to.untag())->num_variables_ =
+        static_cast<UntaggedContext*>(from.untag())->num_variables_;
   } else if (IsTypedDataClassId(cid)) {
     static_cast<UntaggedTypedDataBase*>(to.untag())->length_ =
         static_cast<UntaggedTypedDataBase*>(from.untag())->length_;
@@ -579,33 +586,18 @@ class ObjectCopyBase {
   }
 
     switch (cid) {
-      HANDLE_ILLEGAL_CASE(FunctionType)
+      // From "dart:ffi" we handle only Pointer/DynamicLibrary specially, since
+      // those are the only non-abstract classes (so we avoid checking more cids
+      // here that cannot happen in reality)
       HANDLE_ILLEGAL_CASE(DynamicLibrary)
-      HANDLE_ILLEGAL_CASE(MirrorReference)
       HANDLE_ILLEGAL_CASE(Pointer)
+      HANDLE_ILLEGAL_CASE(FfiDynamicLibrary)
+      HANDLE_ILLEGAL_CASE(FfiPointer)
+      HANDLE_ILLEGAL_CASE(FunctionType)
+      HANDLE_ILLEGAL_CASE(MirrorReference)
       HANDLE_ILLEGAL_CASE(ReceivePort)
       HANDLE_ILLEGAL_CASE(StackTrace)
       HANDLE_ILLEGAL_CASE(UserTag)
-#define CASE(type) case kFfi##type##Cid:
-      CLASS_LIST_FFI(CASE)
-#undef CASE
-      exception_msg_ =
-          "Native objects (from dart:ffi) such as Pointers and "
-          "Structs cannot be passed between isolates.";
-      return false;
-      case kClosureCid: {
-        if (!Function::IsImplicitStaticClosureFunction(
-                Closure::FunctionOf(Closure::RawCast(object)))) {
-          exception_msg_ = OS::SCreate(
-              zone_,
-              "Illegal argument in isolate message: (object is a closure - %s)",
-              Function::Handle(Closure::FunctionOf(Closure::RawCast(object)))
-                  .ToCString());
-          return false;
-        }
-        ASSERT(Closure::ContextOf(Closure::RawCast(object)) == Object::null());
-        return true;
-      }
       default:
         return true;
     }
@@ -672,6 +664,16 @@ class FastObjectCopyBase : public ObjectCopyBase {
     }
   }
 
+  void ForwardContextPointers(intptr_t context_length,
+                              ObjectPtr src,
+                              ObjectPtr dst,
+                              intptr_t offset,
+                              intptr_t end_offset) {
+    for (; offset < end_offset; offset += kWordSize) {
+      ForwardPointer(src, dst, offset);
+    }
+  }
+
   DART_FORCE_INLINE
   void ForwardCompressedPointer(ObjectPtr src, ObjectPtr dst, intptr_t offset) {
     auto value = LoadCompressedPointer(src, offset);
@@ -681,7 +683,7 @@ class FastObjectCopyBase : public ObjectCopyBase {
     }
     auto value_decompressed = value.Decompress(heap_base_);
     const uword tags = TagsFromUntaggedObject(value_decompressed.untag());
-    if (CanShareObject(tags)) {
+    if (CanShareObject(value_decompressed, tags)) {
       StoreCompressedPointerNoBarrier(dst, offset, value);
       return;
     }
@@ -703,6 +705,36 @@ class FastObjectCopyBase : public ObjectCopyBase {
     StoreCompressedPointerNoBarrier(dst, offset, to);
   }
 
+  // TODO(rmacnak): Can be removed if Contexts are compressed.
+  DART_FORCE_INLINE
+  void ForwardPointer(ObjectPtr src, ObjectPtr dst, intptr_t offset) {
+    auto value = LoadPointer(src, offset);
+    if (!value.IsHeapObject()) {
+      StorePointerNoBarrier(dst, offset, value);
+      return;
+    }
+    const uword tags = TagsFromUntaggedObject(value.untag());
+    if (CanShareObject(value, tags)) {
+      StorePointerNoBarrier(dst, offset, value);
+      return;
+    }
+
+    ObjectPtr existing_to = fast_forward_map_.ForwardedObject(value);
+    if (existing_to != Marker()) {
+      StorePointerNoBarrier(dst, offset, existing_to);
+      return;
+    }
+
+    if (UNLIKELY(!CanCopyObject(tags, value))) {
+      ASSERT(exception_msg_ != nullptr);
+      StorePointerNoBarrier(dst, offset, Object::null());
+      return;
+    }
+
+    auto to = Forward(tags, value);
+    StorePointerNoBarrier(dst, offset, to);
+  }
+
   ObjectPtr Forward(uword tags, ObjectPtr from) {
     const intptr_t header_size = UntaggedObject::SizeTag::decode(tags);
     const auto cid = UntaggedObject::ClassIdTag::decode(tags);
@@ -827,6 +859,16 @@ class SlowObjectCopyBase : public ObjectCopyBase {
     }
   }
 
+  void ForwardContextPointers(intptr_t context_length,
+                              const Object& src,
+                              const Object& dst,
+                              intptr_t offset,
+                              intptr_t end_offset) {
+    for (; offset < end_offset; offset += kWordSize) {
+      ForwardPointer(src, dst, offset);
+    }
+  }
+
   DART_FORCE_INLINE
   void ForwardCompressedLargeArrayPointer(const Object& src,
                                           const Object& dst,
@@ -839,7 +881,7 @@ class SlowObjectCopyBase : public ObjectCopyBase {
 
     auto value_decompressed = value.Decompress(heap_base_);
     const uword tags = TagsFromUntaggedObject(value_decompressed.untag());
-    if (CanShareObject(tags)) {
+    if (CanShareObject(value_decompressed, tags)) {
       StoreCompressedLargeArrayPointerBarrier(dst.ptr(), offset,
                                               value_decompressed);
       return;
@@ -874,7 +916,7 @@ class SlowObjectCopyBase : public ObjectCopyBase {
     }
     auto value_decompressed = value.Decompress(heap_base_);
     const uword tags = TagsFromUntaggedObject(value_decompressed.untag());
-    if (CanShareObject(tags)) {
+    if (CanShareObject(value_decompressed, tags)) {
       StoreCompressedPointerBarrier(dst.ptr(), offset, value_decompressed);
       return;
     }
@@ -896,6 +938,37 @@ class SlowObjectCopyBase : public ObjectCopyBase {
     tmp_ = Forward(tags, tmp_);  // Only this can cause allocation.
     StoreCompressedPointerBarrier(dst.ptr(), offset, tmp_.ptr());
   }
+
+  // TODO(rmacnak): Can be removed if Contexts are compressed.
+  DART_FORCE_INLINE
+  void ForwardPointer(const Object& src, const Object& dst, intptr_t offset) {
+    auto value = LoadPointer(src.ptr(), offset);
+    if (!value.IsHeapObject()) {
+      StorePointerNoBarrier(dst.ptr(), offset, value);
+      return;
+    }
+    const uword tags = TagsFromUntaggedObject(value.untag());
+    if (CanShareObject(value, tags)) {
+      StorePointerBarrier(dst.ptr(), offset, value);
+      return;
+    }
+
+    ObjectPtr existing_to = slow_forward_map_.ForwardedObject(value);
+    if (existing_to != Marker()) {
+      StorePointerBarrier(dst.ptr(), offset, existing_to);
+      return;
+    }
+
+    if (UNLIKELY(!CanCopyObject(tags, value))) {
+      ASSERT(exception_msg_ != nullptr);
+      StorePointerNoBarrier(dst.ptr(), offset, Object::null());
+      return;
+    }
+
+    tmp_ = value;
+    tmp_ = Forward(tags, tmp_);  // Only this can cause allocation.
+    StorePointerBarrier(dst.ptr(), offset, tmp_.ptr());
+  }
   ObjectPtr Forward(uword tags, const Object& from) {
     const intptr_t cid = UntaggedObject::ClassIdTag::decode(tags);
     intptr_t size = UntaggedObject::SizeTag::decode(tags);
@@ -1083,6 +1156,18 @@ class ObjectCopy : public Base {
                             UntagClosure(from)->entry_point_);
   }
 
+  void CopyContext(typename Types::Context from, typename Types::Context to) {
+    const intptr_t length = Context::NumVariables(Types::GetContextPtr(from));
+
+    UntagContext(to)->num_variables_ = UntagContext(from)->num_variables_;
+
+    Base::ForwardCompressedPointer(from, to,
+                                   OFFSET_OF(UntaggedContext, parent_));
+    Base::ForwardContextPointers(
+        length, from, to, Context::variable_offset(0),
+        Context::variable_offset(0) + kWordSize * length);
+  }
+
   void CopyArray(typename Types::Array from, typename Types::Array to) {
     const intptr_t length = Smi::Value(UntagArray(from)->length());
     Base::StoreCompressedArrayPointers(
@@ -1671,7 +1756,7 @@ class ObjectGraphCopier {
       return result_array.ptr();
     }
     const uword tags = TagsFromUntaggedObject(root.ptr().untag());
-    if (CanShareObject(tags)) {
+    if (CanShareObject(root.ptr(), tags)) {
       result_array.SetAt(0, root);
       return result_array.ptr();
     }

runtime/vm/raw_object.h

@@ -2179,6 +2179,9 @@ class UntaggedContext : public UntaggedObject {
   VARIABLE_POINTER_FIELDS(ObjectPtr, element, data)
 
   friend class Object;
+  friend void UpdateLengthField(intptr_t,
+                                ObjectPtr,
+                                ObjectPtr);  // num_variables_
 };
 
 class UntaggedContextScope : public UntaggedObject {

tests/lib/isolate/function_send_test.dart

@@ -7,10 +7,15 @@
 // VMOptions=--no-enable-isolate-groups
 
 import "dart:isolate";
+import "dart:io";
 import "dart:async";
+
 import "package:expect/expect.dart";
 import "package:async_helper/async_helper.dart";
 
+final bool isolateGroupsEnabled =
+    Platform.executableArguments.contains('--enable-isolate-groups');
+
 void toplevel(port, message) {
   port.send("toplevel:$message");
 }
@@ -175,6 +180,9 @@ void _call(initPort) {
 }
 
 void testUnsendable(name, func) {
+  // Isolate group support does allow sending closures.
+  if (isolateGroupsEnabled) return;
+
   asyncStart();
   Isolate.spawn(nop, func).then<void>((v) => throw "allowed spawn direct?",
       onError: (e, s) {

tests/lib/isolate/message3_test.dart

@@ -13,11 +13,16 @@ library MessageTest;
 
 import 'dart:async';
 import 'dart:collection';
+import 'dart:io';
 import 'dart:isolate';
+
 import 'package:async_helper/async_helper.dart';
 import 'package:expect/expect.dart';
 import 'dart:typed_data';
 
+final bool isolateGroupsEnabled =
+    Platform.executableArguments.contains('--enable-isolate-groups');
+
 void echoMain(msg) {
   SendPort replyTo = msg[0];
   SendPort pong = msg[1];
@@ -408,7 +413,14 @@ void runTests(SendPort ping, Queue checks) {
     Expect.equals(42, x.fun()); //     //# fun: continued
   }); //                               //# fun: continued
 
-  Expect.throws(() => ping.send(new E(new E(E.fooFun).instanceFun)));
+  if (isolateGroupsEnabled) {
+    ping.send(new E(new E(E.fooFun).instanceFun));
+    checks.add((x) {
+      Expect.equals(1234, (x as E).fun());
+    });
+  } else {
+    Expect.throws(() => ping.send(new E(new E(E.fooFun).instanceFun)));
+  }
 
   F nonConstF = new F();
   ping.send(nonConstF);

tests/lib_2/isolate/function_send_test.dart

@@ -9,10 +9,15 @@
 // VMOptions=--no-enable-isolate-groups
 
 import "dart:isolate";
+import "dart:io";
 import "dart:async";
+
 import "package:expect/expect.dart";
 import "package:async_helper/async_helper.dart";
 
+final bool isolateGroupsEnabled =
+    Platform.executableArguments.contains('--enable-isolate-groups');
+
 void toplevel(port, message) {
   port.send("toplevel:$message");
 }
@@ -151,8 +156,8 @@ Future<SendPort> echoPort(callback(value)) {
     completer.complete(p);
     initPort.close();
   });
-  return Isolate.spawn(_echo, [replyPort, initPort.sendPort]).then(
-      (isolate) => completer.future);
+  return Isolate.spawn(_echo, [replyPort, initPort.sendPort])
+      .then((isolate) => completer.future);
 }
 
 void _echo(msg) {
@@ -178,6 +183,9 @@ void _call(initPort) {
 }
 
 void testUnsendable(name, func) {
+  // Isolate group support does allow sending closures.
+  if (isolateGroupsEnabled) return;
+
   asyncStart();
   Isolate.spawn(nop, func).then((v) => throw "allowed spawn direct?",
       onError: (e, s) {

tests/lib_2/isolate/message3_test.dart

@@ -15,11 +15,16 @@ library MessageTest;
 
 import 'dart:async';
 import 'dart:collection';
+import 'dart:io';
 import 'dart:isolate';
+
 import 'package:async_helper/async_helper.dart';
 import 'package:expect/expect.dart';
 import 'dart:typed_data';
 
+final bool isolateGroupsEnabled =
+    Platform.executableArguments.contains('--enable-isolate-groups');
+
 void echoMain(msg) {
   SendPort replyTo = msg[0];
   SendPort pong = msg[1];
@@ -410,7 +415,14 @@ void runTests(SendPort ping, Queue checks) {
     Expect.equals(42, x.fun()); //     //# fun: continued
   }); //                               //# fun: continued
 
-  Expect.throws(() => ping.send(new E(new E(null).instanceFun)));
+  if (isolateGroupsEnabled) {
+    ping.send(new E(new E(null).instanceFun));
+    checks.add((x) {
+      Expect.equals(1234, (x as E).fun());
+    });
+  } else {
+    Expect.throws(() => ping.send(new E(new E(null).instanceFun)));
+  }
 
   F nonConstF = new F();
   ping.send(nonConstF);