Assert no VM handles are created in the zone that belongs to a ApiNativeScopes.

runtime/vm/snapshot_test.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "platform/globals.h"
 
 #include "include/dart_debugger_api.h"
 #include "platform/assert.h"
 #include "vm/class_finalizer.h"
 #include "vm/dart_api_impl.h"
@@ skipping 223 matching lines @@
 }
 
 
 Dart_CObject* SerializeAndDeserializeMint(const Mint& mint) {
   // Write snapshot with object content.
   uint8_t* buffer;
   MessageWriter writer(&buffer, &zone_allocator, true);
   writer.WriteMessage(mint);
   intptr_t buffer_len = writer.BytesWritten();
 
-  // Read object back from the snapshot.
-  MessageSnapshotReader reader(buffer,
-                               buffer_len,
-                               Isolate::Current(),
-                               Thread::Current()->zone());
-  const Object& serialized_object = Object::Handle(reader.ReadObject());
-  EXPECT(serialized_object.IsMint());
+  {
+    // Switch to a regular zone, where VM handle allocation is allowed.
+    StackZone zone(Isolate::Current());
+    // Read object back from the snapshot.
+    MessageSnapshotReader reader(buffer,
+                                 buffer_len,
+                                 Isolate::Current(),
+                                 Thread::Current()->zone());
+    const Object& serialized_object = Object::Handle(reader.ReadObject());
+    EXPECT(serialized_object.IsMint());
+  }
 
   // Read object back from the snapshot into a C structure.
   ApiMessageReader api_reader(buffer, buffer_len, &zone_allocator);
   Dart_CObject* root = api_reader.ReadMessage();
   EXPECT_NOTNULL(root);
   CheckEncodeDecodeMessage(root);
   return root;
 }
 
 
@@ skipping 173 matching lines @@
 }
 
 
 Dart_CObject* SerializeAndDeserializeBigint(const Bigint& bigint) {
   // Write snapshot with object content.
   uint8_t* buffer;
   MessageWriter writer(&buffer, &zone_allocator, true);
   writer.WriteMessage(bigint);
   intptr_t buffer_len = writer.BytesWritten();
 
-  // Read object back from the snapshot.
-  MessageSnapshotReader reader(buffer,
-                               buffer_len,
-                               Isolate::Current(),
-                               Thread::Current()->zone());
-  Bigint& serialized_bigint = Bigint::Handle();
-  serialized_bigint ^= reader.ReadObject();
-  const char* str1 = bigint.ToHexCString(allocator);
-  const char* str2 = serialized_bigint.ToHexCString(allocator);
-  EXPECT_STREQ(str1, str2);
-  free(const_cast<char*>(str1));
-  free(const_cast<char*>(str2));
+  {
+    // Switch to a regular zone, where VM handle allocation is allowed.
+    StackZone zone(Isolate::Current());
+    // Read object back from the snapshot.
+    MessageSnapshotReader reader(buffer,
+                                 buffer_len,
+                                 Isolate::Current(),
+                                 Thread::Current()->zone());
+    Bigint& serialized_bigint = Bigint::Handle();
+    serialized_bigint ^= reader.ReadObject();
+    const char* str1 = bigint.ToHexCString(allocator);
+    const char* str2 = serialized_bigint.ToHexCString(allocator);
+    EXPECT_STREQ(str1, str2);
+    free(const_cast<char*>(str1));
+    free(const_cast<char*>(str2));
+  }
 
   // Read object back from the snapshot into a C structure.
   ApiMessageReader api_reader(buffer, buffer_len, &zone_allocator);
   Dart_CObject* root = api_reader.ReadMessage();
   // Bigint not supported.
   EXPECT_NOTNULL(root);
   CheckEncodeDecodeMessage(root);
   return root;
 }
 
 
 void CheckBigint(const char* bigint_value) {
   StackZone zone(Isolate::Current());
-  ApiNativeScope scope;
-
   Bigint& bigint = Bigint::Handle();
   bigint ^= Bigint::NewFromCString(bigint_value);
+  ApiNativeScope scope;
   Dart_CObject* bigint_cobject = SerializeAndDeserializeBigint(bigint);
   EXPECT_EQ(Dart_CObject_kBigint, bigint_cobject->type);
   char* hex_value = TestCase::BigintToHexValue(bigint_cobject);
   EXPECT_STREQ(bigint_value, hex_value);
   free(hex_value);
 }
 
 
 TEST_CASE(SerializeBigint2) {
   CheckBigint("0x0");
@@ skipping 1098 matching lines @@
     EXPECT_EQ(Dart_CObject_kInt32, element->type);
     EXPECT_EQ(i + 1, element->value.as_int32);
   }
   CheckEncodeDecodeMessage(root);
 }
 
 
 // Helper function to call a top level Dart function, serialize the
 // result and deserialize the result into a Dart_CObject structure.
 static Dart_CObject* GetDeserializedDartMessage(Dart_Handle lib,
-                                                const char* dart_function) {
+                                                const char* dart_function,
+                                                Object* tmp_handle) {

[siva, 2015/06/19 23:30:46]

Why is it not Ok to allocate the StackZone here instead of passing in a handle
pointer, We are calling Dart_Invoke and it could potentially also create
handles.

[koda, 2015/06/22 17:18:51]

That would make the return value a dangling pointer.

It's true that Dart_Invoke does allocate handles, and it turns out my assertion
did not catch this. The issue is really that the ApiNativeScope should *only* be
around the deserialization (since everything else might allocate handles).

I've updated the CL substantially by:

1. splitting this helper method to allow smaller ApiNativeScopes in the test.
2. adding an ASSERT in handle allocation

PTAL

   Dart_Handle result;
   result = Dart_Invoke(lib, NewString(dart_function), 0, NULL);
   EXPECT_VALID(result);
 
   // Serialize the list into a message.
   uint8_t* buffer;
   MessageWriter writer(&buffer, &zone_allocator, false);
-  const Object& list = Object::Handle(Api::UnwrapHandle(result));
-  writer.WriteMessage(list);
+  *tmp_handle = Api::UnwrapHandle(result);
+  writer.WriteMessage(*tmp_handle);
   intptr_t buffer_len = writer.BytesWritten();
 
   // Read object back from the snapshot into a C structure.
   ApiMessageReader api_reader(buffer, buffer_len, &zone_allocator);
   return api_reader.ReadMessage();
 }
 
 
 static void CheckString(Dart_Handle dart_string, const char* expected) {
   StackZone zone(Isolate::Current());
@@ skipping 209 matching lines @@
   TestCase::CreateTestIsolate();
   Isolate* isolate = Isolate::Current();
   EXPECT(isolate != NULL);
   Dart_EnterScope();
 
   Dart_Handle lib = TestCase::LoadTestScript(kScriptChars, NULL);
   EXPECT_VALID(lib);
 
   {
     DARTSCOPE(isolate);
+    StackZone zone(isolate);
+    Object& tmp = Object::Handle();
     {
       // Generate a list of nulls from Dart code.
       ApiNativeScope scope;
-      Dart_CObject* root = GetDeserializedDartMessage(lib, "getList");
+      Dart_CObject* root = GetDeserializedDartMessage(lib, "getList", &tmp);
       EXPECT_NOTNULL(root);
       EXPECT_EQ(Dart_CObject_kArray, root->type);
       EXPECT_EQ(kArrayLength, root->value.as_array.length);
       for (int i = 0; i < kArrayLength; i++) {
         EXPECT_EQ(Dart_CObject_kNull, root->value.as_array.values[i]->type);
       }
       CheckEncodeDecodeMessage(root);
     }
     {
       // Generate a list of ints from Dart code.
       ApiNativeScope scope;
-      Dart_CObject* root = GetDeserializedDartMessage(lib, "getIntList");
+      Dart_CObject* root = GetDeserializedDartMessage(lib, "getIntList", &tmp);
       EXPECT_NOTNULL(root);
       EXPECT_EQ(Dart_CObject_kArray, root->type);
       EXPECT_EQ(kArrayLength, root->value.as_array.length);
       for (int i = 0; i < kArrayLength; i++) {
         EXPECT_EQ(Dart_CObject_kInt32, root->value.as_array.values[i]->type);
         EXPECT_EQ(i, root->value.as_array.values[i]->value.as_int32);
       }
       CheckEncodeDecodeMessage(root);
     }
     {
       // Generate a list of strings from Dart code.
       ApiNativeScope scope;
-      Dart_CObject* root = GetDeserializedDartMessage(lib, "getStringList");
+      Dart_CObject* root =
+          GetDeserializedDartMessage(lib, "getStringList", &tmp);
       EXPECT_NOTNULL(root);
       EXPECT_EQ(Dart_CObject_kArray, root->type);
       EXPECT_EQ(kArrayLength, root->value.as_array.length);
       for (int i = 0; i < kArrayLength; i++) {
         EXPECT_EQ(Dart_CObject_kString, root->value.as_array.values[i]->type);
         char buffer[3];
         snprintf(buffer, sizeof(buffer), "%d", i);
         EXPECT_STREQ(buffer, root->value.as_array.values[i]->value.as_string);
       }
     }
     {
       // Generate a list of objects of different types from Dart code.
       ApiNativeScope scope;
-      Dart_CObject* root = GetDeserializedDartMessage(lib, "getMixedList");
+      Dart_CObject* root =
+          GetDeserializedDartMessage(lib, "getMixedList", &tmp);
       EXPECT_NOTNULL(root);
       EXPECT_EQ(Dart_CObject_kArray, root->type);
       EXPECT_EQ(kArrayLength, root->value.as_array.length);
 
       EXPECT_EQ(Dart_CObject_kInt32, root->value.as_array.values[0]->type);
       EXPECT_EQ(0, root->value.as_array.values[0]->value.as_int32);
       EXPECT_EQ(Dart_CObject_kString, root->value.as_array.values[1]->type);
       EXPECT_STREQ("1", root->value.as_array.values[1]->value.as_string);
       EXPECT_EQ(Dart_CObject_kDouble, root->value.as_array.values[2]->type);
       EXPECT_EQ(2.2, root->value.as_array.values[2]->value.as_double);
@@ skipping 55 matching lines @@
   TestCase::CreateTestIsolate();
   Isolate* isolate = Isolate::Current();
   EXPECT(isolate != NULL);
   Dart_EnterScope();
 
   Dart_Handle lib = TestCase::LoadTestScript(kScriptChars, NULL);
   EXPECT_VALID(lib);
 
   {
     DARTSCOPE(isolate);
+    StackZone zone(isolate);
+    Object& tmp = Object::Handle();
     {
       // Generate a list of nulls from Dart code.
       ApiNativeScope scope;
-      Dart_CObject* root = GetDeserializedDartMessage(lib, "getList");
+      Dart_CObject* root = GetDeserializedDartMessage(lib, "getList", &tmp);
       EXPECT_NOTNULL(root);
       EXPECT_EQ(Dart_CObject_kArray, root->type);
       EXPECT_EQ(kArrayLength, root->value.as_array.length);
       for (int i = 0; i < kArrayLength; i++) {
         EXPECT_EQ(Dart_CObject_kNull, root->value.as_array.values[i]->type);
       }
       CheckEncodeDecodeMessage(root);
     }
     {
       // Generate a list of ints from Dart code.
       ApiNativeScope scope;
-      Dart_CObject* root = GetDeserializedDartMessage(lib, "getIntList");
+      Dart_CObject* root =
+          GetDeserializedDartMessage(lib, "getIntList", &tmp);
       EXPECT_NOTNULL(root);
       EXPECT_EQ(Dart_CObject_kArray, root->type);
       EXPECT_EQ(kArrayLength, root->value.as_array.length);
       for (int i = 0; i < kArrayLength; i++) {
         EXPECT_EQ(Dart_CObject_kInt32, root->value.as_array.values[i]->type);
         EXPECT_EQ(i, root->value.as_array.values[i]->value.as_int32);
       }
       CheckEncodeDecodeMessage(root);
     }
     {
       // Generate a list of strings from Dart code.
       ApiNativeScope scope;
-      Dart_CObject* root = GetDeserializedDartMessage(lib, "getStringList");
+      Dart_CObject* root =
+          GetDeserializedDartMessage(lib, "getStringList", &tmp);
       EXPECT_NOTNULL(root);
       EXPECT_EQ(Dart_CObject_kArray, root->type);
       EXPECT_EQ(kArrayLength, root->value.as_array.length);
       for (int i = 0; i < kArrayLength; i++) {
         EXPECT_EQ(Dart_CObject_kString, root->value.as_array.values[i]->type);
         char buffer[3];
         snprintf(buffer, sizeof(buffer), "%d", i);
         EXPECT_STREQ(buffer, root->value.as_array.values[i]->value.as_string);
       }
     }
     {
       // Generate a list of lists from Dart code.
       ApiNativeScope scope;
-      Dart_CObject* root = GetDeserializedDartMessage(lib, "getListList");
+      Dart_CObject* root =
+          GetDeserializedDartMessage(lib, "getListList", &tmp);
       EXPECT_NOTNULL(root);
       EXPECT_EQ(Dart_CObject_kArray, root->type);
       EXPECT_EQ(kArrayLength, root->value.as_array.length);
       for (int i = 0; i < kArrayLength; i++) {
         Dart_CObject* element = root->value.as_array.values[i];
         EXPECT_EQ(Dart_CObject_kArray, element->type);
         EXPECT_EQ(i, element->value.as_array.length);
         for (int j = 0; j < i; j++) {
           EXPECT_EQ(Dart_CObject_kInt32,
                     element->value.as_array.values[j]->type);
           EXPECT_EQ(j, element->value.as_array.values[j]->value.as_int32);
         }
       }
     }
     {
       // Generate a list of objects of different types from Dart code.
       ApiNativeScope scope;
-      Dart_CObject* root = GetDeserializedDartMessage(lib, "getMixedList");
+      Dart_CObject* root =
+          GetDeserializedDartMessage(lib, "getMixedList", &tmp);
       EXPECT_NOTNULL(root);
       EXPECT_EQ(Dart_CObject_kArray, root->type);
       EXPECT_EQ(kArrayLength, root->value.as_array.length);
 
       EXPECT_EQ(Dart_CObject_kInt32, root->value.as_array.values[0]->type);
       EXPECT_EQ(0, root->value.as_array.values[0]->value.as_int32);
       EXPECT_EQ(Dart_CObject_kString, root->value.as_array.values[1]->type);
       EXPECT_STREQ("1", root->value.as_array.values[1]->value.as_string);
       EXPECT_EQ(Dart_CObject_kDouble, root->value.as_array.values[2]->type);
       EXPECT_EQ(2.2, root->value.as_array.values[2]->value.as_double);
@@ skipping 151 matching lines @@
   TestCase::CreateTestIsolate();
   Isolate* isolate = Isolate::Current();
   EXPECT(isolate != NULL);
   Dart_EnterScope();
 
   Dart_Handle lib = TestCase::LoadTestScript(kScriptChars, NULL);
   EXPECT_VALID(lib);
 
   {
     DARTSCOPE(isolate);
-
+    StackZone zone(isolate);
+    Object& tmp = Object::Handle();
     {
       // Generate a list of strings from Dart code.
       ApiNativeScope scope;
-      Dart_CObject* root = GetDeserializedDartMessage(lib, "getStringList");
+      Dart_CObject* root =
+          GetDeserializedDartMessage(lib, "getStringList", &tmp);
       EXPECT_NOTNULL(root);
       EXPECT_EQ(Dart_CObject_kArray, root->type);
       EXPECT_EQ(kArrayLength, root->value.as_array.length);
       for (int i = 0; i < kArrayLength; i++) {
         Dart_CObject* element = root->value.as_array.values[i];
         EXPECT_EQ(root->value.as_array.values[0], element);
         EXPECT_EQ(Dart_CObject_kString, element->type);
         EXPECT_STREQ("Hello, world!", element->value.as_string);
       }
     }
     {
       // Generate a list of medium ints from Dart code.
       ApiNativeScope scope;
-      Dart_CObject* root = GetDeserializedDartMessage(lib, "getMintList");
+      Dart_CObject* root =
+          GetDeserializedDartMessage(lib, "getMintList", &tmp);
       EXPECT_NOTNULL(root);
       EXPECT_EQ(Dart_CObject_kArray, root->type);
       EXPECT_EQ(kArrayLength, root->value.as_array.length);
       for (int i = 0; i < kArrayLength; i++) {
         Dart_CObject* element = root->value.as_array.values[i];
         EXPECT_EQ(root->value.as_array.values[0], element);
         EXPECT_EQ(Dart_CObject_kInt64, element->type);
         EXPECT_EQ(DART_INT64_C(0x7FFFFFFFFFFFFFFF), element->value.as_int64);
       }
     }
     {
       // Generate a list of bigints from Dart code.
       ApiNativeScope scope;
-      Dart_CObject* root = GetDeserializedDartMessage(lib, "getBigintList");
+      Dart_CObject* root =
+          GetDeserializedDartMessage(lib, "getBigintList", &tmp);
       EXPECT_NOTNULL(root);
       EXPECT_EQ(Dart_CObject_kArray, root->type);
       EXPECT_EQ(kArrayLength, root->value.as_array.length);
       for (int i = 0; i < kArrayLength; i++) {
         Dart_CObject* element = root->value.as_array.values[i];
         EXPECT_EQ(root->value.as_array.values[0], element);
         EXPECT_EQ(Dart_CObject_kBigint, element->type);
         char* hex_value = TestCase::BigintToHexValue(element);
         EXPECT_STREQ("0x1234567890123456789012345678901234567890", hex_value);
         free(hex_value);
       }
     }
     {
       // Generate a list of doubles from Dart code.
       ApiNativeScope scope;
-      Dart_CObject* root = GetDeserializedDartMessage(lib, "getDoubleList");
+      Dart_CObject* root =
+          GetDeserializedDartMessage(lib, "getDoubleList", &tmp);
       EXPECT_NOTNULL(root);
       EXPECT_EQ(Dart_CObject_kArray, root->type);
       EXPECT_EQ(kArrayLength, root->value.as_array.length);
       Dart_CObject* element = root->value.as_array.values[0];
       EXPECT_EQ(Dart_CObject_kDouble, element->type);
       EXPECT_EQ(3.14, element->value.as_double);
       for (int i = 1; i < kArrayLength; i++) {
         element = root->value.as_array.values[i];
         // Double values are expected to not be canonicalized in messages.
         EXPECT_NE(root->value.as_array.values[0], element);
         EXPECT_EQ(Dart_CObject_kDouble, element->type);
         EXPECT_EQ(3.14, element->value.as_double);
       }
     }
     {
       // Generate a list of Uint8Lists from Dart code.
       ApiNativeScope scope;
-      Dart_CObject* root = GetDeserializedDartMessage(lib, "getTypedDataList");
+      Dart_CObject* root =
+          GetDeserializedDartMessage(lib, "getTypedDataList", &tmp);
       EXPECT_NOTNULL(root);
       EXPECT_EQ(Dart_CObject_kArray, root->type);
       EXPECT_EQ(kArrayLength, root->value.as_array.length);
       for (int i = 0; i < kArrayLength; i++) {
         Dart_CObject* element = root->value.as_array.values[i];
         EXPECT_EQ(root->value.as_array.values[0], element);
         EXPECT_EQ(Dart_CObject_kTypedData, element->type);
         EXPECT_EQ(Dart_TypedData_kUint8, element->value.as_typed_data.type);
         EXPECT_EQ(256, element->value.as_typed_data.length);
       }
     }
     {
       // Generate a list of Uint8List views from Dart code.
       ApiNativeScope scope;
       Dart_CObject* root =
-          GetDeserializedDartMessage(lib, "getTypedDataViewList");
+          GetDeserializedDartMessage(lib, "getTypedDataViewList", &tmp);
       EXPECT_NOTNULL(root);
       EXPECT_EQ(Dart_CObject_kArray, root->type);
       EXPECT_EQ(kArrayLength, root->value.as_array.length);
       for (int i = 0; i < kArrayLength; i++) {
         Dart_CObject* element = root->value.as_array.values[i];
         EXPECT_EQ(root->value.as_array.values[0], element);
         EXPECT_EQ(Dart_CObject_kTypedData, element->type);
         EXPECT_EQ(Dart_TypedData_kUint8, element->value.as_typed_data.type);
         EXPECT_EQ(128, element->value.as_typed_data.length);
         EXPECT_EQ(1, element->value.as_typed_data.values[0]);
         EXPECT_EQ(0, element->value.as_typed_data.values[1]);
       }
     }
     {
       // Generate a list of objects of different types from Dart code.
       ApiNativeScope scope;
-      Dart_CObject* root = GetDeserializedDartMessage(lib, "getMixedList");
+      Dart_CObject* root =
+          GetDeserializedDartMessage(lib, "getMixedList", &tmp);
       EXPECT_NOTNULL(root);
       EXPECT_EQ(Dart_CObject_kArray, root->type);
       EXPECT_EQ(kArrayLength, root->value.as_array.length);
       Dart_CObject* element = root->value.as_array.values[0];
       EXPECT_EQ(Dart_CObject_kString, element->type);
       EXPECT_STREQ("A", element->value.as_string);
       element = root->value.as_array.values[1];
       EXPECT_EQ(Dart_CObject_kDouble, element->type);
       EXPECT_STREQ(2.72, element->value.as_double);
       for (int i = 2; i < kArrayLength; i++) {
         element = root->value.as_array.values[i];
         if ((i % 2) == 0) {
           EXPECT_EQ(root->value.as_array.values[0], element);
           EXPECT_EQ(Dart_CObject_kString, element->type);
           EXPECT_STREQ("A", element->value.as_string);
         } else {
           // Double values are expected to not be canonicalized in messages.
           EXPECT_NE(root->value.as_array.values[1], element);
           EXPECT_EQ(Dart_CObject_kDouble, element->type);
           EXPECT_STREQ(2.72, element->value.as_double);
         }
       }
     }
     {
       // Generate a list of objects of different types from Dart code.
       ApiNativeScope scope;
-      Dart_CObject* root = GetDeserializedDartMessage(lib, "getSelfRefList");
+      Dart_CObject* root =
+          GetDeserializedDartMessage(lib, "getSelfRefList", &tmp);
       EXPECT_NOTNULL(root);
       EXPECT_EQ(Dart_CObject_kArray, root->type);
       EXPECT_EQ(kArrayLength, root->value.as_array.length);
       for (int i = 0; i < kArrayLength; i++) {
         Dart_CObject* element = root->value.as_array.values[i];
         EXPECT_EQ(Dart_CObject_kArray, element->type);
         EXPECT_EQ(root, element);
       }
     }
   }
@@ skipping 70 matching lines @@
   TestCase::CreateTestIsolate();
   Isolate* isolate = Isolate::Current();
   EXPECT(isolate != NULL);
   Dart_EnterScope();
 
   Dart_Handle lib = TestCase::LoadTestScript(kScriptChars, NULL);
   EXPECT_VALID(lib);
 
   {
     DARTSCOPE(isolate);
+    StackZone zone(isolate);
+    Object& tmp = Object::Handle();
     {
       // Generate a list of strings from Dart code.
       ApiNativeScope scope;
-      Dart_CObject* root = GetDeserializedDartMessage(lib, "getStringList");
+      Dart_CObject* root =
+          GetDeserializedDartMessage(lib, "getStringList", &tmp);
       EXPECT_NOTNULL(root);
       EXPECT_EQ(Dart_CObject_kArray, root->type);
       EXPECT_EQ(kArrayLength, root->value.as_array.length);
       for (int i = 0; i < kArrayLength; i++) {
         Dart_CObject* element = root->value.as_array.values[i];
         EXPECT_EQ(root->value.as_array.values[0], element);
         EXPECT_EQ(Dart_CObject_kString, element->type);
         EXPECT_STREQ("Hello, world!", element->value.as_string);
       }
     }
     {
       // Generate a list of medium ints from Dart code.
       ApiNativeScope scope;
-      Dart_CObject* root = GetDeserializedDartMessage(lib, "getMintList");
+      Dart_CObject* root =
+          GetDeserializedDartMessage(lib, "getMintList", &tmp);
       EXPECT_NOTNULL(root);
       EXPECT_EQ(Dart_CObject_kArray, root->type);
       EXPECT_EQ(kArrayLength, root->value.as_array.length);
       for (int i = 0; i < kArrayLength; i++) {
         Dart_CObject* element = root->value.as_array.values[i];
         EXPECT_EQ(root->value.as_array.values[0], element);
         EXPECT_EQ(Dart_CObject_kInt64, element->type);
         EXPECT_EQ(DART_INT64_C(0x7FFFFFFFFFFFFFFF), element->value.as_int64);
       }
     }
     {
       // Generate a list of bigints from Dart code.
       ApiNativeScope scope;
-      Dart_CObject* root = GetDeserializedDartMessage(lib, "getBigintList");
+      Dart_CObject* root =
+          GetDeserializedDartMessage(lib, "getBigintList", &tmp);
       EXPECT_NOTNULL(root);
       EXPECT_EQ(Dart_CObject_kArray, root->type);
       EXPECT_EQ(kArrayLength, root->value.as_array.length);
       for (int i = 0; i < kArrayLength; i++) {
         Dart_CObject* element = root->value.as_array.values[i];
         EXPECT_EQ(root->value.as_array.values[0], element);
         EXPECT_EQ(Dart_CObject_kBigint, element->type);
         char* hex_value = TestCase::BigintToHexValue(element);
         EXPECT_STREQ("0x1234567890123456789012345678901234567890", hex_value);
         free(hex_value);
       }
     }
     {
       // Generate a list of doubles from Dart code.
       ApiNativeScope scope;
-      Dart_CObject* root = GetDeserializedDartMessage(lib, "getDoubleList");
+      Dart_CObject* root =
+          GetDeserializedDartMessage(lib, "getDoubleList", &tmp);
       EXPECT_NOTNULL(root);
       EXPECT_EQ(Dart_CObject_kArray, root->type);
       EXPECT_EQ(kArrayLength, root->value.as_array.length);
       Dart_CObject* element = root->value.as_array.values[0];
       // Double values are expected to not be canonicalized in messages.
       EXPECT_EQ(Dart_CObject_kDouble, element->type);
       EXPECT_EQ(3.14, element->value.as_double);
       for (int i = 1; i < kArrayLength; i++) {
         element = root->value.as_array.values[i];
         // Double values are expected to not be canonicalized in messages.
         EXPECT_NE(root->value.as_array.values[0], element);
         EXPECT_EQ(Dart_CObject_kDouble, element->type);
         EXPECT_EQ(3.14, element->value.as_double);
       }
     }
     {
       // Generate a list of Uint8Lists from Dart code.
       ApiNativeScope scope;
-      Dart_CObject* root = GetDeserializedDartMessage(lib, "getTypedDataList");
+      Dart_CObject* root =
+          GetDeserializedDartMessage(lib, "getTypedDataList", &tmp);
       EXPECT_NOTNULL(root);
       EXPECT_EQ(Dart_CObject_kArray, root->type);
       EXPECT_EQ(kArrayLength, root->value.as_array.length);
       for (int i = 0; i < kArrayLength; i++) {
         Dart_CObject* element = root->value.as_array.values[i];
         EXPECT_EQ(root->value.as_array.values[0], element);
         EXPECT_EQ(Dart_CObject_kTypedData, element->type);
         EXPECT_EQ(Dart_TypedData_kUint8, element->value.as_typed_data.type);
         EXPECT_EQ(256, element->value.as_typed_data.length);
       }
     }
     {
       // Generate a list of Uint8List views from Dart code.
       ApiNativeScope scope;
       Dart_CObject* root =
-          GetDeserializedDartMessage(lib, "getTypedDataViewList");
+          GetDeserializedDartMessage(lib, "getTypedDataViewList", &tmp);
       EXPECT_NOTNULL(root);
       EXPECT_EQ(Dart_CObject_kArray, root->type);
       EXPECT_EQ(kArrayLength, root->value.as_array.length);
       for (int i = 0; i < kArrayLength; i++) {
         Dart_CObject* element = root->value.as_array.values[i];
         EXPECT_EQ(root->value.as_array.values[0], element);
         EXPECT_EQ(Dart_CObject_kTypedData, element->type);
         EXPECT_EQ(Dart_TypedData_kUint8, element->value.as_typed_data.type);
         EXPECT_EQ(128, element->value.as_typed_data.length);
         EXPECT_EQ(1, element->value.as_typed_data.values[0]);
         EXPECT_EQ(0, element->value.as_typed_data.values[1]);
       }
     }
     {
       // Generate a list of objects of different types from Dart code.
       ApiNativeScope scope;
-      Dart_CObject* root = GetDeserializedDartMessage(lib, "getMixedList");
+      Dart_CObject* root =
+          GetDeserializedDartMessage(lib, "getMixedList", &tmp);
       EXPECT_NOTNULL(root);
       EXPECT_EQ(Dart_CObject_kArray, root->type);
       EXPECT_EQ(kArrayLength, root->value.as_array.length);
       Dart_CObject* element = root->value.as_array.values[0];
       EXPECT_EQ(Dart_CObject_kString, element->type);
       EXPECT_STREQ(".", element->value.as_string);
       element = root->value.as_array.values[1];
       EXPECT_EQ(Dart_CObject_kDouble, element->type);
       EXPECT_STREQ(2.72, element->value.as_double);
       for (int i = 2; i < kArrayLength; i++) {
         Dart_CObject* element = root->value.as_array.values[i];
         if ((i % 2) == 0) {
           EXPECT_EQ(root->value.as_array.values[0], element);
           EXPECT_EQ(Dart_CObject_kString, element->type);
           EXPECT_STREQ(".", element->value.as_string);
         } else {
           // Double values are expected to not be canonicalized in messages.
           EXPECT_NE(root->value.as_array.values[1], element);
           EXPECT_EQ(Dart_CObject_kDouble, element->type);
           EXPECT_STREQ(2.72, element->value.as_double);
         }
       }
     }
     {
       // Generate a list of objects of different types from Dart code.
       ApiNativeScope scope;
-      Dart_CObject* root = GetDeserializedDartMessage(lib, "getSelfRefList");
+      Dart_CObject* root =
+          GetDeserializedDartMessage(lib, "getSelfRefList", &tmp);
       EXPECT_NOTNULL(root);
       EXPECT_EQ(Dart_CObject_kArray, root->type);
       EXPECT_EQ(kArrayLength, root->value.as_array.length);
       for (int i = 0; i < kArrayLength; i++) {
         Dart_CObject* element = root->value.as_array.values[i];
         EXPECT_EQ(Dart_CObject_kArray, element->type);
         EXPECT_EQ(root, element);
       }
     }
   }
@@ skipping 85 matching lines @@
   TestCase::CreateTestIsolate();
   Isolate* isolate = Isolate::Current();
   EXPECT(isolate != NULL);
   Dart_EnterScope();
 
   Dart_Handle lib = TestCase::LoadTestScript(kScriptChars, NULL);
   EXPECT_VALID(lib);
 
   {
     DARTSCOPE(isolate);
+    StackZone zone(isolate);
+    Object& tmp = Object::Handle();
     {
       // Generate a list of Uint8Lists from Dart code.
       ApiNativeScope scope;
-      Dart_CObject* root = GetDeserializedDartMessage(lib, "getTypedDataList");
+      Dart_CObject* root =
+          GetDeserializedDartMessage(lib, "getTypedDataList", &tmp);
       EXPECT_NOTNULL(root);
       EXPECT_EQ(Dart_CObject_kArray, root->type);
       struct {
         Dart_TypedData_Type type;
         int size;
       } expected[] = {
         { Dart_TypedData_kInt8, 256},
         { Dart_TypedData_kUint8, 256},
         { Dart_TypedData_kInt16, 512},
         { Dart_TypedData_kUint16, 512},
@@ skipping 13 matching lines @@
                        expected[i].size);
         i++;
       }
       EXPECT_EQ(i, root->value.as_array.length);
     }
     {
       // Generate a list of Uint8List views from Dart code.
 
       ApiNativeScope scope;
       Dart_CObject* root =
-          GetDeserializedDartMessage(lib, "getTypedDataViewList");
+          GetDeserializedDartMessage(lib, "getTypedDataViewList", &tmp);
       EXPECT_NOTNULL(root);
       EXPECT_EQ(Dart_CObject_kArray, root->type);
       struct {
         Dart_TypedData_Type type;
         int size;
       } expected[] = {
         { Dart_TypedData_kInt8, 256},
         { Dart_TypedData_kUint8, 256},
         { Dart_TypedData_kInt16, 512},
         { Dart_TypedData_kUint16, 512},
@@ skipping 35 matching lines @@
                        expected[i].type,
                        expected[i].size);
         i++;
       }
       EXPECT_EQ(i, root->value.as_array.length);
     }
     {
       // Generate a list of Uint8Lists from Dart code.
       ApiNativeScope scope;
       Dart_CObject* root =
-          GetDeserializedDartMessage(lib, "getMultipleTypedDataViewList");
+          GetDeserializedDartMessage(lib, "getMultipleTypedDataViewList", &tmp);
       EXPECT_NOTNULL(root);
       EXPECT_EQ(Dart_CObject_kArray, root->type);
       struct {
         Dart_TypedData_Type type;
         int size;
       } expected[] = {
         { Dart_TypedData_kInt8, 256},
         { Dart_TypedData_kUint8, 256},
         { Dart_TypedData_kInt16, 256},
         { Dart_TypedData_kUint16, 256},
@@ skipping 125 matching lines @@
   StackZone zone(Isolate::Current());
   uint8_t* buffer;
   MessageWriter writer(&buffer, &zone_allocator, true);
   writer.WriteInlinedObjectHeader(kOmittedObjectId);
   // For performance, we'd like single-byte headers when ids are omitted.
   // If this starts failing, consider renumbering the snapshot ids.
   EXPECT_EQ(1, writer.BytesWritten());
 }
 
 }  // namespace dart