runtime/vm/object_id_ring_test.cc - sdk - Git at Google

 // Copyright (c) 2013, 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 "vm/object_id_ring.h"
 #include "platform/assert.h"
 #include "vm/dart_api_impl.h"
 #include "vm/dart_api_state.h"
 #include "vm/globals.h"
 #include "vm/symbols.h"
 #include "vm/unit_test.h"

 namespace dart {

 #ifndef PRODUCT

 class ObjectIdRingTestHelper {
  public:
   static void SetCapacityAndMaxSerial(ObjectIdRing* ring,
                                       int32_t capacity,
                                       int32_t max_serial) {
     ring->SetCapacityAndMaxSerial(capacity, max_serial);
   }

   static void ExpectIdIsValid(ObjectIdRing* ring, intptr_t id) {
     EXPECT(ring->IsValidId(id));
   }

   static void ExpectIdIsInvalid(ObjectIdRing* ring, intptr_t id) {
     EXPECT(!ring->IsValidId(id));
   }

   static void ExpectIndexId(ObjectIdRing* ring, intptr_t index, intptr_t id) {
     EXPECT_EQ(id, ring->IdOfIndex(index));
   }

   static void ExpectInvalidIndex(ObjectIdRing* ring, intptr_t index) {
     EXPECT_EQ(-1, ring->IdOfIndex(index));
   }

   static ObjectPtr MakeString(const char* s) {
     return Symbols::New(Thread::Current(), s);
   }

   static void ExpectString(ObjectPtr obj, const char* s) {
     String& str = String::Handle();
     str ^= obj;
     EXPECT(str.Equals(s));
   }
 };

 // Test that serial number wrapping works.
 ISOLATE_UNIT_TEST_CASE(ObjectIdRingSerialWrapTest) {
   Isolate* isolate = Isolate::Current();
   ObjectIdRing* ring = isolate->EnsureObjectIdRing();
   ObjectIdRingTestHelper::SetCapacityAndMaxSerial(ring, 2, 4);
   intptr_t id;
   ObjectIdRing::LookupResult kind = ObjectIdRing::kInvalid;
   id = ring->GetIdForObject(ObjectIdRingTestHelper::MakeString("0"));
   EXPECT_EQ(0, id);
   ObjectIdRingTestHelper::ExpectIndexId(ring, 0, 0);
   ObjectIdRingTestHelper::ExpectInvalidIndex(ring, 1);
   id = ring->GetIdForObject(ObjectIdRingTestHelper::MakeString("1"));
   EXPECT_EQ(1, id);
   ObjectIdRingTestHelper::ExpectIndexId(ring, 0, 0);
   ObjectIdRingTestHelper::ExpectIndexId(ring, 1, 1);
   // Test that id 1 gives us the "1" string.
   ObjectIdRingTestHelper::ExpectString(ring->GetObjectForId(id, &kind), "1");
   EXPECT_EQ(ObjectIdRing::kValid, kind);
   ObjectIdRingTestHelper::ExpectIdIsValid(ring, 0);
   ObjectIdRingTestHelper::ExpectIndexId(ring, 0, 0);
   ObjectIdRingTestHelper::ExpectIdIsValid(ring, 1);
   ObjectIdRingTestHelper::ExpectIndexId(ring, 1, 1);
   ObjectIdRingTestHelper::ExpectIdIsInvalid(ring, 2);
   ObjectIdRingTestHelper::ExpectIdIsInvalid(ring, 3);
   // We have wrapped, index 0 is being reused.
   id = ring->GetIdForObject(ObjectIdRingTestHelper::MakeString("2"));
   EXPECT_EQ(2, id);
   ObjectIdRingTestHelper::ExpectIdIsInvalid(ring, 0);
   ObjectIdRingTestHelper::ExpectIdIsValid(ring, 1);
   // Index 0 has id 2.
   ObjectIdRingTestHelper::ExpectIndexId(ring, 0, 2);
   ObjectIdRingTestHelper::ExpectIdIsValid(ring, 2);
   // Index 1 has id 1.
   ObjectIdRingTestHelper::ExpectIndexId(ring, 1, 1);
   ObjectIdRingTestHelper::ExpectIdIsInvalid(ring, 3);
   id = ring->GetIdForObject(ObjectIdRingTestHelper::MakeString("3"));
   EXPECT_EQ(3, id);
   // Index 0 has id 2.
   ObjectIdRingTestHelper::ExpectIndexId(ring, 0, 2);
   // Index 1 has id 3.
   ObjectIdRingTestHelper::ExpectIndexId(ring, 1, 3);
   ObjectIdRingTestHelper::ExpectIdIsInvalid(ring, 0);
   ObjectIdRingTestHelper::ExpectIdIsInvalid(ring, 1);
   ObjectIdRingTestHelper::ExpectIdIsValid(ring, 2);
   ObjectIdRingTestHelper::ExpectIdIsValid(ring, 3);
   id = ring->GetIdForObject(ObjectIdRingTestHelper::MakeString("4"));
   EXPECT_EQ(0, id);
   // Index 0 has id 0.
   ObjectIdRingTestHelper::ExpectIndexId(ring, 0, 0);
   // Index 1 has id 3.
   ObjectIdRingTestHelper::ExpectIndexId(ring, 1, 3);
   ObjectIdRingTestHelper::ExpectString(ring->GetObjectForId(id, &kind), "4");
   EXPECT_EQ(ObjectIdRing::kValid, kind);
   ObjectIdRingTestHelper::ExpectIdIsValid(ring, 0);
   ObjectIdRingTestHelper::ExpectIdIsInvalid(ring, 1);
   ObjectIdRingTestHelper::ExpectIdIsInvalid(ring, 2);
   ObjectIdRingTestHelper::ExpectIdIsValid(ring, 3);
   id = ring->GetIdForObject(ObjectIdRingTestHelper::MakeString("5"));
   EXPECT_EQ(1, id);
   // Index 0 has id 0.
   ObjectIdRingTestHelper::ExpectIndexId(ring, 0, 0);
   // Index 1 has id 1.
   ObjectIdRingTestHelper::ExpectIndexId(ring, 1, 1);
   ObjectIdRingTestHelper::ExpectString(ring->GetObjectForId(id, &kind), "5");
   EXPECT_EQ(ObjectIdRing::kValid, kind);
   ObjectIdRingTestHelper::ExpectIdIsValid(ring, 0);
   ObjectIdRingTestHelper::ExpectIdIsValid(ring, 1);
   ObjectIdRingTestHelper::ExpectIdIsInvalid(ring, 2);
   ObjectIdRingTestHelper::ExpectIdIsInvalid(ring, 3);
 }

 // Test that the ring table is updated when the scavenger moves an object.
 TEST_CASE(ObjectIdRingScavengeMoveTest) {
   const char* kScriptChars =
       "main() {\n"
       "  return [1, 2, 3];\n"
       "}\n";
   Dart_Handle lib = TestCase::LoadTestScript(kScriptChars, NULL);
   Dart_Handle result = Dart_Invoke(lib, NewString("main"), 0, NULL);
   Dart_Handle moved_handle;
   intptr_t list_length = 0;
   EXPECT_VALID(result);
   EXPECT(!Dart_IsNull(result));
   EXPECT(Dart_IsList(result));
   EXPECT_VALID(Dart_ListLength(result, &list_length));
   EXPECT_EQ(3, list_length);

   Isolate* isolate = thread->isolate();
   ObjectIdRing* ring = isolate->EnsureObjectIdRing();
   ObjectIdRing::LookupResult kind = ObjectIdRing::kInvalid;

   {
     TransitionNativeToVM to_vm(thread);
     ObjectPtr raw_obj = Api::UnwrapHandle(result);
     // Located in new heap.
     EXPECT(raw_obj->IsNewObject());
     EXPECT_NE(Object::null(), raw_obj);
     intptr_t raw_obj_id1 = ring->GetIdForObject(raw_obj);
     EXPECT_EQ(0, raw_obj_id1);
     // Get id 0 again.
     EXPECT_EQ(raw_obj_id1,
               ring->GetIdForObject(raw_obj, ObjectIdRing::kReuseId));
     // Add to ring a second time.
     intptr_t raw_obj_id2 = ring->GetIdForObject(raw_obj);
     EXPECT_EQ(1, raw_obj_id2);
     // Get id 0 again.
     EXPECT_EQ(raw_obj_id1,
               ring->GetIdForObject(raw_obj, ObjectIdRing::kReuseId));
     ObjectPtr raw_obj1 = ring->GetObjectForId(raw_obj_id1, &kind);
     EXPECT_EQ(ObjectIdRing::kValid, kind);
     ObjectPtr raw_obj2 = ring->GetObjectForId(raw_obj_id2, &kind);
     EXPECT_EQ(ObjectIdRing::kValid, kind);
     EXPECT_NE(Object::null(), raw_obj1);
     EXPECT_NE(Object::null(), raw_obj2);
     EXPECT_EQ(ObjectLayout::ToAddr(raw_obj), ObjectLayout::ToAddr(raw_obj1));
     EXPECT_EQ(ObjectLayout::ToAddr(raw_obj), ObjectLayout::ToAddr(raw_obj2));
     // Force a scavenge.
     GCTestHelper::CollectNewSpace();
     ObjectPtr raw_object_moved1 = ring->GetObjectForId(raw_obj_id1, &kind);
     EXPECT_EQ(ObjectIdRing::kValid, kind);
     ObjectPtr raw_object_moved2 = ring->GetObjectForId(raw_obj_id2, &kind);
     EXPECT_EQ(ObjectIdRing::kValid, kind);
     EXPECT_NE(Object::null(), raw_object_moved1);
     EXPECT_NE(Object::null(), raw_object_moved2);
     EXPECT_EQ(ObjectLayout::ToAddr(raw_object_moved1),
               ObjectLayout::ToAddr(raw_object_moved2));
     // Test that objects have moved.
     EXPECT_NE(ObjectLayout::ToAddr(raw_obj1),
               ObjectLayout::ToAddr(raw_object_moved1));
     EXPECT_NE(ObjectLayout::ToAddr(raw_obj2),
               ObjectLayout::ToAddr(raw_object_moved2));
     // Test that we still point at the same list.
     moved_handle = Api::NewHandle(thread, raw_object_moved1);
     // Test id reuse.
     EXPECT_EQ(raw_obj_id1,
               ring->GetIdForObject(raw_object_moved1, ObjectIdRing::kReuseId));
   }
   EXPECT_VALID(moved_handle);
   EXPECT(!Dart_IsNull(moved_handle));
   EXPECT(Dart_IsList(moved_handle));
   EXPECT_VALID(Dart_ListLength(moved_handle, &list_length));
   EXPECT_EQ(3, list_length);
 }

 // Test that the ring table is updated with nulls when the old GC collects.
 ISOLATE_UNIT_TEST_CASE(ObjectIdRingOldGCTest) {
   Isolate* isolate = thread->isolate();
   ObjectIdRing* ring = isolate->EnsureObjectIdRing();

   ObjectIdRing::LookupResult kind = ObjectIdRing::kInvalid;
   intptr_t raw_obj_id1 = -1;
   intptr_t raw_obj_id2 = -1;
   {
     HandleScope handle_scope(thread);
     const String& str = String::Handle(String::New("old", Heap::kOld));
     EXPECT(!str.IsNull());
     EXPECT_EQ(3, str.Length());

     ObjectPtr raw_obj = Object::RawCast(str.raw());
     // Verify that it is located in old heap.
     EXPECT(raw_obj->IsOldObject());
     EXPECT_NE(Object::null(), raw_obj);
     raw_obj_id1 = ring->GetIdForObject(raw_obj);
     EXPECT_EQ(0, raw_obj_id1);
     raw_obj_id2 = ring->GetIdForObject(raw_obj);
     EXPECT_EQ(1, raw_obj_id2);
     ObjectPtr raw_obj1 = ring->GetObjectForId(raw_obj_id1, &kind);
     EXPECT_EQ(ObjectIdRing::kValid, kind);
     ObjectPtr raw_obj2 = ring->GetObjectForId(raw_obj_id2, &kind);
     EXPECT_EQ(ObjectIdRing::kValid, kind);
     EXPECT_NE(Object::null(), raw_obj1);
     EXPECT_NE(Object::null(), raw_obj2);
     EXPECT_EQ(ObjectLayout::ToAddr(raw_obj), ObjectLayout::ToAddr(raw_obj1));
     EXPECT_EQ(ObjectLayout::ToAddr(raw_obj), ObjectLayout::ToAddr(raw_obj2));
     // Exit scope. Freeing String handle.
   }
   // Force a GC. No reference exist to the old string anymore. It should be
   // collected and the object id ring will now return the null object for
   // those ids.
   GCTestHelper::CollectOldSpace();
   ObjectPtr raw_object_moved1 = ring->GetObjectForId(raw_obj_id1, &kind);
   EXPECT_EQ(ObjectIdRing::kCollected, kind);
   EXPECT_EQ(Object::null(), raw_object_moved1);
   ObjectPtr raw_object_moved2 = ring->GetObjectForId(raw_obj_id2, &kind);
   EXPECT_EQ(ObjectIdRing::kCollected, kind);
   EXPECT_EQ(Object::null(), raw_object_moved2);
 }

 // Test that the ring table correctly reports an entry as expired when it is
 // overridden by new entries.
 ISOLATE_UNIT_TEST_CASE(ObjectIdRingExpiredEntryTest) {
   Isolate* isolate = Isolate::Current();
   ObjectIdRing* ring = isolate->EnsureObjectIdRing();

   // Insert an object and check we can look it up.
   String& obj = String::Handle(String::New("I will expire"));
   intptr_t obj_id = ring->GetIdForObject(obj.raw());
   ObjectIdRing::LookupResult kind = ObjectIdRing::kInvalid;
   ObjectPtr obj_lookup = ring->GetObjectForId(obj_id, &kind);
   EXPECT_EQ(ObjectIdRing::kValid, kind);
   EXPECT_EQ(obj.raw(), obj_lookup);

   // Insert as many new objects as the ring size to bump out our first entry.
   Object& new_obj = Object::Handle();
   for (intptr_t i = 0; i < ObjectIdRing::kDefaultCapacity; i++) {
     new_obj = String::New("Bump");
     intptr_t new_obj_id = ring->GetIdForObject(new_obj.raw());
     ObjectIdRing::LookupResult kind = ObjectIdRing::kInvalid;
     ObjectPtr new_obj_lookup = ring->GetObjectForId(new_obj_id, &kind);
     EXPECT_EQ(ObjectIdRing::kValid, kind);
     EXPECT_EQ(new_obj.raw(), new_obj_lookup);
   }

   // Check our first entry reports it has expired.
   obj_lookup = ring->GetObjectForId(obj_id, &kind);
   EXPECT_EQ(ObjectIdRing::kExpired, kind);
   EXPECT_NE(obj.raw(), obj_lookup);
   EXPECT_EQ(Object::null(), obj_lookup);
 }

 #endif  // !PRODUCT

 }  // namespace dart
	// Copyright (c) 2013, 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 "vm/object_id_ring.h"
	#include "platform/assert.h"
	#include "vm/dart_api_impl.h"
	#include "vm/dart_api_state.h"
	#include "vm/globals.h"
	#include "vm/symbols.h"
	#include "vm/unit_test.h"

	namespace dart {

	#ifndef PRODUCT

	class ObjectIdRingTestHelper {
	public:
	static void SetCapacityAndMaxSerial(ObjectIdRing* ring,
	int32_t capacity,
	int32_t max_serial) {
	ring->SetCapacityAndMaxSerial(capacity, max_serial);
	}

	static void ExpectIdIsValid(ObjectIdRing* ring, intptr_t id) {
	EXPECT(ring->IsValidId(id));
	}

	static void ExpectIdIsInvalid(ObjectIdRing* ring, intptr_t id) {
	EXPECT(!ring->IsValidId(id));
	}

	static void ExpectIndexId(ObjectIdRing* ring, intptr_t index, intptr_t id) {
	EXPECT_EQ(id, ring->IdOfIndex(index));
	}

	static void ExpectInvalidIndex(ObjectIdRing* ring, intptr_t index) {
	EXPECT_EQ(-1, ring->IdOfIndex(index));
	}

	static ObjectPtr MakeString(const char* s) {
	return Symbols::New(Thread::Current(), s);
	}

	static void ExpectString(ObjectPtr obj, const char* s) {
	String& str = String::Handle();
	str ^= obj;
	EXPECT(str.Equals(s));
	}
	};

	// Test that serial number wrapping works.
	ISOLATE_UNIT_TEST_CASE(ObjectIdRingSerialWrapTest) {
	Isolate* isolate = Isolate::Current();
	ObjectIdRing* ring = isolate->EnsureObjectIdRing();
	ObjectIdRingTestHelper::SetCapacityAndMaxSerial(ring, 2, 4);
	intptr_t id;
	ObjectIdRing::LookupResult kind = ObjectIdRing::kInvalid;
	id = ring->GetIdForObject(ObjectIdRingTestHelper::MakeString("0"));
	EXPECT_EQ(0, id);
	ObjectIdRingTestHelper::ExpectIndexId(ring, 0, 0);
	ObjectIdRingTestHelper::ExpectInvalidIndex(ring, 1);
	id = ring->GetIdForObject(ObjectIdRingTestHelper::MakeString("1"));
	EXPECT_EQ(1, id);
	ObjectIdRingTestHelper::ExpectIndexId(ring, 0, 0);
	ObjectIdRingTestHelper::ExpectIndexId(ring, 1, 1);
	// Test that id 1 gives us the "1" string.
	ObjectIdRingTestHelper::ExpectString(ring->GetObjectForId(id, &kind), "1");
	EXPECT_EQ(ObjectIdRing::kValid, kind);
	ObjectIdRingTestHelper::ExpectIdIsValid(ring, 0);
	ObjectIdRingTestHelper::ExpectIndexId(ring, 0, 0);
	ObjectIdRingTestHelper::ExpectIdIsValid(ring, 1);
	ObjectIdRingTestHelper::ExpectIndexId(ring, 1, 1);
	ObjectIdRingTestHelper::ExpectIdIsInvalid(ring, 2);
	ObjectIdRingTestHelper::ExpectIdIsInvalid(ring, 3);
	// We have wrapped, index 0 is being reused.
	id = ring->GetIdForObject(ObjectIdRingTestHelper::MakeString("2"));
	EXPECT_EQ(2, id);
	ObjectIdRingTestHelper::ExpectIdIsInvalid(ring, 0);
	ObjectIdRingTestHelper::ExpectIdIsValid(ring, 1);
	// Index 0 has id 2.
	ObjectIdRingTestHelper::ExpectIndexId(ring, 0, 2);
	ObjectIdRingTestHelper::ExpectIdIsValid(ring, 2);
	// Index 1 has id 1.
	ObjectIdRingTestHelper::ExpectIndexId(ring, 1, 1);
	ObjectIdRingTestHelper::ExpectIdIsInvalid(ring, 3);
	id = ring->GetIdForObject(ObjectIdRingTestHelper::MakeString("3"));
	EXPECT_EQ(3, id);
	// Index 0 has id 2.
	ObjectIdRingTestHelper::ExpectIndexId(ring, 0, 2);
	// Index 1 has id 3.
	ObjectIdRingTestHelper::ExpectIndexId(ring, 1, 3);
	ObjectIdRingTestHelper::ExpectIdIsInvalid(ring, 0);
	ObjectIdRingTestHelper::ExpectIdIsInvalid(ring, 1);
	ObjectIdRingTestHelper::ExpectIdIsValid(ring, 2);
	ObjectIdRingTestHelper::ExpectIdIsValid(ring, 3);
	id = ring->GetIdForObject(ObjectIdRingTestHelper::MakeString("4"));
	EXPECT_EQ(0, id);
	// Index 0 has id 0.
	ObjectIdRingTestHelper::ExpectIndexId(ring, 0, 0);
	// Index 1 has id 3.
	ObjectIdRingTestHelper::ExpectIndexId(ring, 1, 3);
	ObjectIdRingTestHelper::ExpectString(ring->GetObjectForId(id, &kind), "4");
	EXPECT_EQ(ObjectIdRing::kValid, kind);
	ObjectIdRingTestHelper::ExpectIdIsValid(ring, 0);
	ObjectIdRingTestHelper::ExpectIdIsInvalid(ring, 1);
	ObjectIdRingTestHelper::ExpectIdIsInvalid(ring, 2);
	ObjectIdRingTestHelper::ExpectIdIsValid(ring, 3);
	id = ring->GetIdForObject(ObjectIdRingTestHelper::MakeString("5"));
	EXPECT_EQ(1, id);
	// Index 0 has id 0.
	ObjectIdRingTestHelper::ExpectIndexId(ring, 0, 0);
	// Index 1 has id 1.
	ObjectIdRingTestHelper::ExpectIndexId(ring, 1, 1);
	ObjectIdRingTestHelper::ExpectString(ring->GetObjectForId(id, &kind), "5");
	EXPECT_EQ(ObjectIdRing::kValid, kind);
	ObjectIdRingTestHelper::ExpectIdIsValid(ring, 0);
	ObjectIdRingTestHelper::ExpectIdIsValid(ring, 1);
	ObjectIdRingTestHelper::ExpectIdIsInvalid(ring, 2);
	ObjectIdRingTestHelper::ExpectIdIsInvalid(ring, 3);
	}

	// Test that the ring table is updated when the scavenger moves an object.
	TEST_CASE(ObjectIdRingScavengeMoveTest) {
	const char* kScriptChars =
	"main() {\n"
	" return [1, 2, 3];\n"
	"}\n";
	Dart_Handle lib = TestCase::LoadTestScript(kScriptChars, NULL);
	Dart_Handle result = Dart_Invoke(lib, NewString("main"), 0, NULL);
	Dart_Handle moved_handle;
	intptr_t list_length = 0;
	EXPECT_VALID(result);
	EXPECT(!Dart_IsNull(result));
	EXPECT(Dart_IsList(result));
	EXPECT_VALID(Dart_ListLength(result, &list_length));
	EXPECT_EQ(3, list_length);

	Isolate* isolate = thread->isolate();
	ObjectIdRing* ring = isolate->EnsureObjectIdRing();
	ObjectIdRing::LookupResult kind = ObjectIdRing::kInvalid;

	{
	TransitionNativeToVM to_vm(thread);
	ObjectPtr raw_obj = Api::UnwrapHandle(result);
	// Located in new heap.
	EXPECT(raw_obj->IsNewObject());
	EXPECT_NE(Object::null(), raw_obj);
	intptr_t raw_obj_id1 = ring->GetIdForObject(raw_obj);
	EXPECT_EQ(0, raw_obj_id1);
	// Get id 0 again.
	EXPECT_EQ(raw_obj_id1,
	ring->GetIdForObject(raw_obj, ObjectIdRing::kReuseId));
	// Add to ring a second time.
	intptr_t raw_obj_id2 = ring->GetIdForObject(raw_obj);
	EXPECT_EQ(1, raw_obj_id2);
	// Get id 0 again.
	EXPECT_EQ(raw_obj_id1,
	ring->GetIdForObject(raw_obj, ObjectIdRing::kReuseId));
	ObjectPtr raw_obj1 = ring->GetObjectForId(raw_obj_id1, &kind);
	EXPECT_EQ(ObjectIdRing::kValid, kind);
	ObjectPtr raw_obj2 = ring->GetObjectForId(raw_obj_id2, &kind);
	EXPECT_EQ(ObjectIdRing::kValid, kind);
	EXPECT_NE(Object::null(), raw_obj1);
	EXPECT_NE(Object::null(), raw_obj2);
	EXPECT_EQ(ObjectLayout::ToAddr(raw_obj), ObjectLayout::ToAddr(raw_obj1));
	EXPECT_EQ(ObjectLayout::ToAddr(raw_obj), ObjectLayout::ToAddr(raw_obj2));
	// Force a scavenge.
	GCTestHelper::CollectNewSpace();
	ObjectPtr raw_object_moved1 = ring->GetObjectForId(raw_obj_id1, &kind);
	EXPECT_EQ(ObjectIdRing::kValid, kind);
	ObjectPtr raw_object_moved2 = ring->GetObjectForId(raw_obj_id2, &kind);
	EXPECT_EQ(ObjectIdRing::kValid, kind);
	EXPECT_NE(Object::null(), raw_object_moved1);
	EXPECT_NE(Object::null(), raw_object_moved2);
	EXPECT_EQ(ObjectLayout::ToAddr(raw_object_moved1),
	ObjectLayout::ToAddr(raw_object_moved2));
	// Test that objects have moved.
	EXPECT_NE(ObjectLayout::ToAddr(raw_obj1),
	ObjectLayout::ToAddr(raw_object_moved1));
	EXPECT_NE(ObjectLayout::ToAddr(raw_obj2),
	ObjectLayout::ToAddr(raw_object_moved2));
	// Test that we still point at the same list.
	moved_handle = Api::NewHandle(thread, raw_object_moved1);
	// Test id reuse.
	EXPECT_EQ(raw_obj_id1,
	ring->GetIdForObject(raw_object_moved1, ObjectIdRing::kReuseId));
	}
	EXPECT_VALID(moved_handle);
	EXPECT(!Dart_IsNull(moved_handle));
	EXPECT(Dart_IsList(moved_handle));
	EXPECT_VALID(Dart_ListLength(moved_handle, &list_length));
	EXPECT_EQ(3, list_length);
	}

	// Test that the ring table is updated with nulls when the old GC collects.
	ISOLATE_UNIT_TEST_CASE(ObjectIdRingOldGCTest) {
	Isolate* isolate = thread->isolate();
	ObjectIdRing* ring = isolate->EnsureObjectIdRing();

	ObjectIdRing::LookupResult kind = ObjectIdRing::kInvalid;
	intptr_t raw_obj_id1 = -1;
	intptr_t raw_obj_id2 = -1;
	{
	HandleScope handle_scope(thread);
	const String& str = String::Handle(String::New("old", Heap::kOld));
	EXPECT(!str.IsNull());
	EXPECT_EQ(3, str.Length());

	ObjectPtr raw_obj = Object::RawCast(str.raw());
	// Verify that it is located in old heap.
	EXPECT(raw_obj->IsOldObject());
	EXPECT_NE(Object::null(), raw_obj);
	raw_obj_id1 = ring->GetIdForObject(raw_obj);
	EXPECT_EQ(0, raw_obj_id1);
	raw_obj_id2 = ring->GetIdForObject(raw_obj);
	EXPECT_EQ(1, raw_obj_id2);
	ObjectPtr raw_obj1 = ring->GetObjectForId(raw_obj_id1, &kind);
	EXPECT_EQ(ObjectIdRing::kValid, kind);
	ObjectPtr raw_obj2 = ring->GetObjectForId(raw_obj_id2, &kind);
	EXPECT_EQ(ObjectIdRing::kValid, kind);
	EXPECT_NE(Object::null(), raw_obj1);
	EXPECT_NE(Object::null(), raw_obj2);
	EXPECT_EQ(ObjectLayout::ToAddr(raw_obj), ObjectLayout::ToAddr(raw_obj1));
	EXPECT_EQ(ObjectLayout::ToAddr(raw_obj), ObjectLayout::ToAddr(raw_obj2));
	// Exit scope. Freeing String handle.
	}
	// Force a GC. No reference exist to the old string anymore. It should be
	// collected and the object id ring will now return the null object for
	// those ids.
	GCTestHelper::CollectOldSpace();
	ObjectPtr raw_object_moved1 = ring->GetObjectForId(raw_obj_id1, &kind);
	EXPECT_EQ(ObjectIdRing::kCollected, kind);
	EXPECT_EQ(Object::null(), raw_object_moved1);
	ObjectPtr raw_object_moved2 = ring->GetObjectForId(raw_obj_id2, &kind);
	EXPECT_EQ(ObjectIdRing::kCollected, kind);
	EXPECT_EQ(Object::null(), raw_object_moved2);
	}

	// Test that the ring table correctly reports an entry as expired when it is
	// overridden by new entries.
	ISOLATE_UNIT_TEST_CASE(ObjectIdRingExpiredEntryTest) {
	Isolate* isolate = Isolate::Current();
	ObjectIdRing* ring = isolate->EnsureObjectIdRing();

	// Insert an object and check we can look it up.
	String& obj = String::Handle(String::New("I will expire"));
	intptr_t obj_id = ring->GetIdForObject(obj.raw());
	ObjectIdRing::LookupResult kind = ObjectIdRing::kInvalid;
	ObjectPtr obj_lookup = ring->GetObjectForId(obj_id, &kind);
	EXPECT_EQ(ObjectIdRing::kValid, kind);
	EXPECT_EQ(obj.raw(), obj_lookup);

	// Insert as many new objects as the ring size to bump out our first entry.
	Object& new_obj = Object::Handle();
	for (intptr_t i = 0; i < ObjectIdRing::kDefaultCapacity; i++) {
	new_obj = String::New("Bump");
	intptr_t new_obj_id = ring->GetIdForObject(new_obj.raw());
	ObjectIdRing::LookupResult kind = ObjectIdRing::kInvalid;
	ObjectPtr new_obj_lookup = ring->GetObjectForId(new_obj_id, &kind);
	EXPECT_EQ(ObjectIdRing::kValid, kind);
	EXPECT_EQ(new_obj.raw(), new_obj_lookup);
	}

	// Check our first entry reports it has expired.
	obj_lookup = ring->GetObjectForId(obj_id, &kind);
	EXPECT_EQ(ObjectIdRing::kExpired, kind);
	EXPECT_NE(obj.raw(), obj_lookup);
	EXPECT_EQ(Object::null(), obj_lookup);
	}

	#endif // !PRODUCT

	} // namespace dart