text: // Copyright 2006-2008 the V8 project authors. All rights reserved.
  
  #include <stdlib.h>
  
  #include "v8.h"
  
  #include "execution.h"
  #include "factory.h"
  #include "macro-assembler.h"
  #include "global-handles.h"
  #include "cctest.h"
  
  using namespace v8::internal;
  
  static v8::Persistent<v8::Context> env;
  
  static void InitializeVM() {
    if (env.IsEmpty()) env = v8::Context::New();
    v8::HandleScope scope;
    env->Enter();
  }
  
  
  static void CheckMap(Map* map, int type, int instance_size) {
    CHECK(map->IsHeapObject());
  #ifdef DEBUG
    CHECK(HEAP->Contains(map));
  #endif
    CHECK_EQ(HEAP->meta_map(), map->map());
    CHECK_EQ(type, map->instance_type());
    CHECK_EQ(instance_size, map->instance_size());
  }
  
  
  TEST(HeapMaps) {
    InitializeVM();
    CheckMap(HEAP->meta_map(), MAP_TYPE, Map::kSize);
    CheckMap(HEAP->heap_number_map(), HEAP_NUMBER_TYPE, HeapNumber::kSize);
    CheckMap(HEAP->fixed_array_map(), FIXED_ARRAY_TYPE, kVariableSizeSentinel);
    CheckMap(HEAP->string_map(), STRING_TYPE, kVariableSizeSentinel);
  }
  
  
  static void CheckOddball(Object* obj, const char* string) {
    CHECK(obj->IsOddball());
    bool exc;
    Object* print_string = *Execution::ToString(Handle<Object>(obj), &exc);
    CHECK(String::cast(print_string)->IsEqualTo(CStrVector(string)));
  }
  
  
  static void CheckSmi(int value, const char* string) {
    bool exc;
    Object* print_string =
        *Execution::ToString(Handle<Object>(Smi::FromInt(value)), &exc);
    CHECK(String::cast(print_string)->IsEqualTo(CStrVector(string)));
  }
  
  
  static void CheckNumber(double value, const char* string) {
    Object* obj = HEAP->NumberFromDouble(value)->ToObjectChecked();
    CHECK(obj->IsNumber());
    bool exc;
    Object* print_string = *Execution::ToString(Handle<Object>(obj), &exc);
    CHECK(String::cast(print_string)->IsEqualTo(CStrVector(string)));
  }
  
  
  static void CheckFindCodeObject() {
    // Test FindCodeObject
  #define __ assm.
  
    Assembler assm(Isolate::Current(), NULL, 0);
  
    __ nop();  // supported on all architectures
  
    CodeDesc desc;
    assm.GetCode(&desc);
    Object* code = HEAP->CreateCode(
        desc,
        Code::ComputeFlags(Code::STUB),
        Handle<Object>(HEAP->undefined_value()))->ToObjectChecked();
    CHECK(code->IsCode());
  
    HeapObject* obj = HeapObject::cast(code);
    Address obj_addr = obj->address();
  
    for (int i = 0; i < obj->Size(); i += kPointerSize) {
      Object* found = HEAP->FindCodeObject(obj_addr + i);
      CHECK_EQ(code, found);
    }
  
    Object* copy = HEAP->CreateCode(
        desc,
        Code::ComputeFlags(Code::STUB),
        Handle<Object>(HEAP->undefined_value()))->ToObjectChecked();
    CHECK(copy->IsCode());
    HeapObject* obj_copy = HeapObject::cast(copy);
    Object* not_right = HEAP->FindCodeObject(obj_copy->address() +
                                             obj_copy->Size() / 2);
    CHECK(not_right != code);
  }
  
  
  TEST(HeapObjects) {
    InitializeVM();
  
    v8::HandleScope sc;
    Object* value = HEAP->NumberFromDouble(1.000123)->ToObjectChecked();
    CHECK(value->IsHeapNumber());
    CHECK(value->IsNumber());
    CHECK_EQ(1.000123, value->Number());
  
    value = HEAP->NumberFromDouble(1.0)->ToObjectChecked();
    CHECK(value->IsSmi());
    CHECK(value->IsNumber());
    CHECK_EQ(1.0, value->Number());
  
    value = HEAP->NumberFromInt32(1024)->ToObjectChecked();
    CHECK(value->IsSmi());
    CHECK(value->IsNumber());
    CHECK_EQ(1024.0, value->Number());
  
    value = HEAP->NumberFromInt32(Smi::kMinValue)->ToObjectChecked();
    CHECK(value->IsSmi());
    CHECK(value->IsNumber());
    CHECK_EQ(Smi::kMinValue, Smi::cast(value)->value());
  
    value = HEAP->NumberFromInt32(Smi::kMaxValue)->ToObjectChecked();
    CHECK(value->IsSmi());
    CHECK(value->IsNumber());
    CHECK_EQ(Smi::kMaxValue, Smi::cast(value)->value());
  
  #ifndef V8_TARGET_ARCH_X64
    // TODO(lrn): We need a NumberFromIntptr function in order to test this.
    value = HEAP->NumberFromInt32(Smi::kMinValue - 1)->ToObjectChecked();
    CHECK(value->IsHeapNumber());
    CHECK(value->IsNumber());
    CHECK_EQ(static_cast<double>(Smi::kMinValue - 1), value->Number());
  #endif
  
    MaybeObject* maybe_value =
        HEAP->NumberFromUint32(static_cast<uint32_t>(Smi::kMaxValue) + 1);
    value = maybe_value->ToObjectChecked();
    CHECK(value->IsHeapNumber());
    CHECK(value->IsNumber());
    CHECK_EQ(static_cast<double>(static_cast<uint32_t>(Smi::kMaxValue) + 1),
             value->Number());
  
    // nan oddball checks
    CHECK(HEAP->nan_value()->IsNumber());
    CHECK(isnan(HEAP->nan_value()->Number()));
  
    Handle<String> s = FACTORY->NewStringFromAscii(CStrVector("fisk hest "));
    CHECK(s->IsString());
    CHECK_EQ(10, s->length());
  
    String* object_symbol = String::cast(HEAP->Object_symbol());
    CHECK(
        Isolate::Current()->context()->global()->HasLocalProperty(object_symbol));
  
    // Check ToString for oddballs
    CheckOddball(HEAP->true_value(), "true");
    CheckOddball(HEAP->false_value(), "false");
    CheckOddball(HEAP->null_value(), "null");
    CheckOddball(HEAP->undefined_value(), "undefined");
  
    // Check ToString for Smis
    CheckSmi(0, "0");
    CheckSmi(42, "42");
    CheckSmi(-42, "-42");
  
    // Check ToString for Numbers
    CheckNumber(1.1, "1.1");
  
    CheckFindCodeObject();
  }
  
  
  TEST(Tagging) {
    InitializeVM();
    int request = 24;
    CHECK_EQ(request, static_cast<int>(OBJECT_POINTER_ALIGN(request)));
    CHECK(Smi::FromInt(42)->IsSmi());
    CHECK(Failure::RetryAfterGC(NEW_SPACE)->IsFailure());
    CHECK_EQ(NEW_SPACE,
             Failure::RetryAfterGC(NEW_SPACE)->allocation_space());
    CHECK_EQ(OLD_POINTER_SPACE,
             Failure::RetryAfterGC(OLD_POINTER_SPACE)->allocation_space());
    CHECK(Failure::Exception()->IsFailure());
    CHECK(Smi::FromInt(Smi::kMinValue)->IsSmi());
    CHECK(Smi::FromInt(Smi::kMaxValue)->IsSmi());
  }
  
  
  TEST(GarbageCollection) {
    InitializeVM();
  
    v8::HandleScope sc;
    // Check GC.
    HEAP->CollectGarbage(NEW_SPACE);
  
    Handle<String> name = FACTORY->LookupAsciiSymbol("theFunction");
    Handle<String> prop_name = FACTORY->LookupAsciiSymbol("theSlot");
    Handle<String> prop_namex = FACTORY->LookupAsciiSymbol("theSlotx");
    Handle<String> obj_name = FACTORY->LookupAsciiSymbol("theObject");
  
    {
      v8::HandleScope inner_scope;
      // Allocate a function and keep it in global object's property.
      Handle<JSFunction> function =
          FACTORY->NewFunction(name, FACTORY->undefined_value());
      Handle<Map> initial_map =
          FACTORY->NewMap(JS_OBJECT_TYPE, JSObject::kHeaderSize);
      function->set_initial_map(*initial_map);
      Isolate::Current()->context()->global()->SetProperty(
          *name, *function, NONE, kNonStrictMode)->ToObjectChecked();
      // Allocate an object.  Unrooted after leaving the scope.
      Handle<JSObject> obj = FACTORY->NewJSObject(function);
      obj->SetProperty(
          *prop_name, Smi::FromInt(23), NONE, kNonStrictMode)->ToObjectChecked();
      obj->SetProperty(
          *prop_namex, Smi::FromInt(24), NONE, kNonStrictMode)->ToObjectChecked();
  
      CHECK_EQ(Smi::FromInt(23), obj->GetProperty(*prop_name));
      CHECK_EQ(Smi::FromInt(24), obj->GetProperty(*prop_namex));
    }
  
    HEAP->CollectGarbage(NEW_SPACE);
  
    // Function should be alive.
    CHECK(Isolate::Current()->context()->global()->HasLocalProperty(*name));
    // Check function is retained.
    Object* func_value = Isolate::Current()->context()->global()->
        GetProperty(*name)->ToObjectChecked();
    CHECK(func_value->IsJSFunction());
    Handle<JSFunction> function(JSFunction::cast(func_value));
  
    {
      HandleScope inner_scope;
      // Allocate another object, make it reachable from global.
      Handle<JSObject> obj = FACTORY->NewJSObject(function);
      Isolate::Current()->context()->global()->SetProperty(
          *obj_name, *obj, NONE, kNonStrictMode)->ToObjectChecked();
      obj->SetProperty(
          *prop_name, Smi::FromInt(23), NONE, kNonStrictMode)->ToObjectChecked();
    }
  
    // After gc, it should survive.
    HEAP->CollectGarbage(NEW_SPACE);
  
    CHECK(Isolate::Current()->context()->global()->HasLocalProperty(*obj_name));
    CHECK(Isolate::Current()->context()->global()->
          GetProperty(*obj_name)->ToObjectChecked()->IsJSObject());
    Object* obj = Isolate::Current()->context()->global()->
        GetProperty(*obj_name)->ToObjectChecked();
    JSObject* js_obj = JSObject::cast(obj);
    CHECK_EQ(Smi::FromInt(23), js_obj->GetProperty(*prop_name));
  }
  
  
  static void VerifyStringAllocation(const char* string) {
    v8::HandleScope scope;
    Handle<String> s = FACTORY->NewStringFromUtf8(CStrVector(string));
    CHECK_EQ(StrLength(string), s->length());
    for (int index = 0; index < s->length(); index++) {
      CHECK_EQ(static_cast<uint16_t>(string[index]), s->Get(index));
    }
  }
  
  
  TEST(String) {
    InitializeVM();
  
    VerifyStringAllocation("a");
    VerifyStringAllocation("ab");
    VerifyStringAllocation("abc");
    VerifyStringAllocation("abcd");
    VerifyStringAllocation("fiskerdrengen er paa havet");
  }
  
  
  TEST(LocalHandles) {
    InitializeVM();
  
    v8::HandleScope scope;
    const char* name = "Kasper the spunky";
    Handle<String> string = FACTORY->NewStringFromAscii(CStrVector(name));
    CHECK_EQ(StrLength(name), string->length());
  }
  
  
  TEST(GlobalHandles) {
    InitializeVM();
    GlobalHandles* global_handles = Isolate::Current()->global_handles();
  
    Handle<Object> h1;
    Handle<Object> h2;
    Handle<Object> h3;
    Handle<Object> h4;
  
    {
      HandleScope scope;
  
      Handle<Object> i = FACTORY->NewStringFromAscii(CStrVector("fisk"));
      Handle<Object> u = FACTORY->NewNumber(1.12344);
  
      h1 = global_handles->Create(*i);
      h2 = global_handles->Create(*u);
      h3 = global_handles->Create(*i);
      h4 = global_handles->Create(*u);
    }
  
    // after gc, it should survive
    HEAP->CollectGarbage(NEW_SPACE);
  
    CHECK((*h1)->IsString());
    CHECK((*h2)->IsHeapNumber());
    CHECK((*h3)->IsString());
    CHECK((*h4)->IsHeapNumber());
  
    CHECK_EQ(*h3, *h1);
    global_handles->Destroy(h1.location());
    global_handles->Destroy(h3.location());
  
    CHECK_EQ(*h4, *h2);
    global_handles->Destroy(h2.location());
    global_handles->Destroy(h4.location());
  }
  
  
  static bool WeakPointerCleared = false;
  
  static void TestWeakGlobalHandleCallback(v8::Persistent<v8::Value> handle,
                                           void* id) {
    if (1234 == reinterpret_cast<intptr_t>(id)) WeakPointerCleared = true;
    handle.Dispose();
  }
  
  
  TEST(WeakGlobalHandlesScavenge) {
    InitializeVM();
    GlobalHandles* global_handles = Isolate::Current()->global_handles();
  
    WeakPointerCleared = false;
  
    Handle<Object> h1;
    Handle<Object> h2;
  
    {
      HandleScope scope;
  
      Handle<Object> i = FACTORY->NewStringFromAscii(CStrVector("fisk"));
      Handle<Object> u = FACTORY->NewNumber(1.12344);
  
      h1 = global_handles->Create(*i);
      h2 = global_handles->Create(*u);
    }
  
    global_handles->MakeWeak(h2.location(),
                             reinterpret_cast<void*>(1234),
                             &TestWeakGlobalHandleCallback);
  
    // Scavenge treats weak pointers as normal roots.
    HEAP->PerformScavenge();
  
    CHECK((*h1)->IsString());
    CHECK((*h2)->IsHeapNumber());
  
    CHECK(!WeakPointerCleared);
    CHECK(!global_handles->IsNearDeath(h2.location()));
    CHECK(!global_handles->IsNearDeath(h1.location()));
  
    global_handles->Destroy(h1.location());
    global_handles->Destroy(h2.location());
  }
  
  
  TEST(WeakGlobalHandlesMark) {
    InitializeVM();
    GlobalHandles* global_handles = Isolate::Current()->global_handles();
  
    WeakPointerCleared = false;
  
    Handle<Object> h1;
    Handle<Object> h2;
  
    {
      HandleScope scope;
  
      Handle<Object> i = FACTORY->NewStringFromAscii(CStrVector("fisk"));
      Handle<Object> u = FACTORY->NewNumber(1.12344);
  
      h1 = global_handles->Create(*i);
      h2 = global_handles->Create(*u);
    }
  
    HEAP->CollectGarbage(OLD_POINTER_SPACE);
    HEAP->CollectGarbage(NEW_SPACE);
    // Make sure the object is promoted.
  
    global_handles->MakeWeak(h2.location(),
                             reinterpret_cast<void*>(1234),
                             &TestWeakGlobalHandleCallback);
    CHECK(!GlobalHandles::IsNearDeath(h1.location()));
    CHECK(!GlobalHandles::IsNearDeath(h2.location()));
  
    HEAP->CollectGarbage(OLD_POINTER_SPACE);
  
    CHECK((*h1)->IsString());
  
    CHECK(WeakPointerCleared);
    CHECK(!GlobalHandles::IsNearDeath(h1.location()));
  
    global_handles->Destroy(h1.location());
  }
  
  TEST(DeleteWeakGlobalHandle) {
    InitializeVM();
    GlobalHandles* global_handles = Isolate::Current()->global_handles();
  
    WeakPointerCleared = false;
  
    Handle<Object> h;
  
    {
      HandleScope scope;
  
      Handle<Object> i = FACTORY->NewStringFromAscii(CStrVector("fisk"));
      h = global_handles->Create(*i);
    }
  
    global_handles->MakeWeak(h.location(),
                             reinterpret_cast<void*>(1234),
                             &TestWeakGlobalHandleCallback);
  
    // Scanvenge does not recognize weak reference.
    HEAP->PerformScavenge();
  
    CHECK(!WeakPointerCleared);
  
    // Mark-compact treats weak reference properly.
    HEAP->CollectGarbage(OLD_POINTER_SPACE);
  
    CHECK(WeakPointerCleared);
  }
  
  static const char* not_so_random_string_table[] = {
    "abstract",
    "boolean",
    "break",
    "byte",
    "case",
    "catch",
    "char",
    "class",
    "const",
    "continue",
    "debugger",
    "default",
    "delete",
    "do",
    "double",
    "else",
    "enum",
    "export",
    "extends",
    "false",
    "final",
    "finally",
    "float",
    "for",
    "function",
    "goto",
    "if",
    "implements",
    "import",
    "in",
    "instanceof",
    "int",
    "interface",
    "long",
    "native",
    "new",
    "null",
    "package",
    "private",
    "protected",
    "public",
    "return",
    "short",
    "static",
    "super",
    "switch",
    "synchronized",
    "this",
    "throw",
    "throws",
    "transient",
    "true",
    "try",
    "typeof",
    "var",
    "void",
    "volatile",
    "while",
    "with",
    0
  };
  
  
  static void CheckSymbols(const char** strings) {
    for (const char* string = *strings; *strings != 0; string = *strings++) {
      Object* a;
      MaybeObject* maybe_a = HEAP->LookupAsciiSymbol(string);
      // LookupAsciiSymbol may return a failure if a GC is needed.
      if (!maybe_a->ToObject(&a)) continue;
      CHECK(a->IsSymbol());
      Object* b;
      MaybeObject* maybe_b = HEAP->LookupAsciiSymbol(string);
      if (!maybe_b->ToObject(&b)) continue;
      CHECK_EQ(b, a);
      CHECK(String::cast(b)->IsEqualTo(CStrVector(string)));
    }
  }
  
  
  TEST(SymbolTable) {
    InitializeVM();
  
    CheckSymbols(not_so_random_string_table);
    CheckSymbols(not_so_random_string_table);
  }
  
  
  TEST(FunctionAllocation) {
    InitializeVM();
  
    v8::HandleScope sc;
    Handle<String> name = FACTORY->LookupAsciiSymbol("theFunction");
    Handle<JSFunction> function =
        FACTORY->NewFunction(name, FACTORY->undefined_value());
    Handle<Map> initial_map =
        FACTORY->NewMap(JS_OBJECT_TYPE, JSObject::kHeaderSize);
    function->set_initial_map(*initial_map);
  
    Handle<String> prop_name = FACTORY->LookupAsciiSymbol("theSlot");
    Handle<JSObject> obj = FACTORY->NewJSObject(function);
    obj->SetProperty(
        *prop_name, Smi::FromInt(23), NONE, kNonStrictMode)->ToObjectChecked();
    CHECK_EQ(Smi::FromInt(23), obj->GetProperty(*prop_name));
    // Check that we can add properties to function objects.
    function->SetProperty(
        *prop_name, Smi::FromInt(24), NONE, kNonStrictMode)->ToObjectChecked();
    CHECK_EQ(Smi::FromInt(24), function->GetProperty(*prop_name));
  }
  
  
  TEST(ObjectProperties) {
    InitializeVM();
  
    v8::HandleScope sc;
    String* object_symbol = String::cast(HEAP->Object_symbol());
    Object* raw_object = Isolate::Current()->context()->global()->
        GetProperty(object_symbol)->ToObjectChecked();
    JSFunction* object_function = JSFunction::cast(raw_object);
    Handle<JSFunction> constructor(object_function);
    Handle<JSObject> obj = FACTORY->NewJSObject(constructor);
    Handle<String> first = FACTORY->LookupAsciiSymbol("first");
    Handle<String> second = FACTORY->LookupAsciiSymbol("second");
  
    // check for empty
    CHECK(!obj->HasLocalProperty(*first));
  
    // add first
    obj->SetProperty(
        *first, Smi::FromInt(1), NONE, kNonStrictMode)->ToObjectChecked();
    CHECK(obj->HasLocalProperty(*first));
  
    // delete first
    CHECK(obj->DeleteProperty(*first, JSObject::NORMAL_DELETION));
    CHECK(!obj->HasLocalProperty(*first));
  
    // add first and then second
    obj->SetProperty(
        *first, Smi::FromInt(1), NONE, kNonStrictMode)->ToObjectChecked();
    obj->SetProperty(
        *second, Smi::FromInt(2), NONE, kNonStrictMode)->ToObjectChecked();
    CHECK(obj->HasLocalProperty(*first));
    CHECK(obj->HasLocalProperty(*second));
  
    // delete first and then second
    CHECK(obj->DeleteProperty(*first, JSObject::NORMAL_DELETION));
    CHECK(obj->HasLocalProperty(*second));
    CHECK(obj->DeleteProperty(*second, JSObject::NORMAL_DELETION));
    CHECK(!obj->HasLocalProperty(*first));
    CHECK(!obj->HasLocalProperty(*second));
  
    // add first and then second
    obj->SetProperty(
        *first, Smi::FromInt(1), NONE, kNonStrictMode)->ToObjectChecked();
    obj->SetProperty(
        *second, Smi::FromInt(2), NONE, kNonStrictMode)->ToObjectChecked();
    CHECK(obj->HasLocalProperty(*first));
    CHECK(obj->HasLocalProperty(*second));
  
    // delete second and then first
    CHECK(obj->DeleteProperty(*second, JSObject::NORMAL_DELETION));
    CHECK(obj->HasLocalProperty(*first));
    CHECK(obj->DeleteProperty(*first, JSObject::NORMAL_DELETION));
    CHECK(!obj->HasLocalProperty(*first));
    CHECK(!obj->HasLocalProperty(*second));
  
    // check string and symbol match
    static const char* string1 = "fisk";
    Handle<String> s1 = FACTORY->NewStringFromAscii(CStrVector(string1));
    obj->SetProperty(
        *s1, Smi::FromInt(1), NONE, kNonStrictMode)->ToObjectChecked();
    Handle<String> s1_symbol = FACTORY->LookupAsciiSymbol(string1);
    CHECK(obj->HasLocalProperty(*s1_symbol));
  
    // check symbol and string match
    static const char* string2 = "fugl";
    Handle<String> s2_symbol = FACTORY->LookupAsciiSymbol(string2);
    obj->SetProperty(
        *s2_symbol, Smi::FromInt(1), NONE, kNonStrictMode)->ToObjectChecked();
    Handle<String> s2 = FACTORY->NewStringFromAscii(CStrVector(string2));
    CHECK(obj->HasLocalProperty(*s2));
  }
  
  
  TEST(JSObjectMaps) {
    InitializeVM();
  
    v8::HandleScope sc;
    Handle<String> name = FACTORY->LookupAsciiSymbol("theFunction");
    Handle<JSFunction> function =
        FACTORY->NewFunction(name, FACTORY->undefined_value());
    Handle<Map> initial_map =
        FACTORY->NewMap(JS_OBJECT_TYPE, JSObject::kHeaderSize);
    function->set_initial_map(*initial_map);
  
    Handle<String> prop_name = FACTORY->LookupAsciiSymbol("theSlot");
    Handle<JSObject> obj = FACTORY->NewJSObject(function);
  
    // Set a propery
    obj->SetProperty(
        *prop_name, Smi::FromInt(23), NONE, kNonStrictMode)->ToObjectChecked();
    CHECK_EQ(Smi::FromInt(23), obj->GetProperty(*prop_name));
  
    // Check the map has changed
    CHECK(*initial_map != obj->map());
  }
  
  
  TEST(JSArray) {
    InitializeVM();
  
    v8::HandleScope sc;
    Handle<String> name = FACTORY->LookupAsciiSymbol("Array");
    Object* raw_object = Isolate::Current()->context()->global()->
        GetProperty(*name)->ToObjectChecked();
    Handle<JSFunction> function = Handle<JSFunction>(
        JSFunction::cast(raw_object));
  
    // Allocate the object.
    Handle<JSObject> object = FACTORY->NewJSObject(function);
    Handle<JSArray> array = Handle<JSArray>::cast(object);
    // We just initialized the VM, no heap allocation failure yet.
    Object* ok = array->Initialize(0)->ToObjectChecked();
  
    // Set array length to 0.
    ok = array->SetElementsLength(Smi::FromInt(0))->ToObjectChecked();
    CHECK_EQ(Smi::FromInt(0), array->length());
    CHECK(array->HasFastElements());  // Must be in fast mode.
  
    // array[length] = name.
    ok = array->SetElement(0, *name, kNonStrictMode)->ToObjectChecked();
    CHECK_EQ(Smi::FromInt(1), array->length());
    CHECK_EQ(array->GetElement(0), *name);
  
    // Set array length with larger than smi value.
    Handle<Object> length =
        FACTORY->NewNumberFromUint(static_cast<uint32_t>(Smi::kMaxValue) + 1);
    ok = array->SetElementsLength(*length)->ToObjectChecked();
  
    uint32_t int_length = 0;
    CHECK(length->ToArrayIndex(&int_length));
    CHECK_EQ(*length, array->length());
    CHECK(array->HasDictionaryElements());  // Must be in slow mode.
  
    // array[length] = name.
    ok = array->SetElement(int_length, *name, kNonStrictMode)->ToObjectChecked();
    uint32_t new_int_length = 0;
    CHECK(array->length()->ToArrayIndex(&new_int_length));
    CHECK_EQ(static_cast<double>(int_length), new_int_length - 1);
    CHECK_EQ(array->GetElement(int_length), *name);
    CHECK_EQ(array->GetElement(0), *name);
  }
  
  
  TEST(JSObjectCopy) {
    InitializeVM();
  
    v8::HandleScope sc;
    String* object_symbol = String::cast(HEAP->Object_symbol());
    Object* raw_object = Isolate::Current()->context()->global()->
        GetProperty(object_symbol)->ToObjectChecked();
    JSFunction* object_function = JSFunction::cast(raw_object);
    Handle<JSFunction> constructor(object_function);
    Handle<JSObject> obj = FACTORY->NewJSObject(constructor);
    Handle<String> first = FACTORY->LookupAsciiSymbol("first");
    Handle<String> second = FACTORY->LookupAsciiSymbol("second");
  
    obj->SetProperty(
        *first, Smi::FromInt(1), NONE, kNonStrictMode)->ToObjectChecked();
    obj->SetProperty(
        *second, Smi::FromInt(2), NONE, kNonStrictMode)->ToObjectChecked();
  
    Object* ok = obj->SetElement(0, *first, kNonStrictMode)->ToObjectChecked();
  
    ok = obj->SetElement(1, *second, kNonStrictMode)->ToObjectChecked();
  
    // Make the clone.
    Handle<JSObject> clone = Copy(obj);
    CHECK(!clone.is_identical_to(obj));
  
    CHECK_EQ(obj->GetElement(0), clone->GetElement(0));
    CHECK_EQ(obj->GetElement(1), clone->GetElement(1));
  
    CHECK_EQ(obj->GetProperty(*first), clone->GetProperty(*first));
    CHECK_EQ(obj->GetProperty(*second), clone->GetProperty(*second));
  
    // Flip the values.
    clone->SetProperty(
        *first, Smi::FromInt(2), NONE, kNonStrictMode)->ToObjectChecked();
    clone->SetProperty(
        *second, Smi::FromInt(1), NONE, kNonStrictMode)->ToObjectChecked();
  
    ok = clone->SetElement(0, *second, kNonStrictMode)->ToObjectChecked();
    ok = clone->SetElement(1, *first, kNonStrictMode)->ToObjectChecked();
  
    CHECK_EQ(obj->GetElement(1), clone->GetElement(0));
    CHECK_EQ(obj->GetElement(0), clone->GetElement(1));
  
    CHECK_EQ(obj->GetProperty(*second), clone->GetProperty(*first));
    CHECK_EQ(obj->GetProperty(*first), clone->GetProperty(*second));
  }
  
  
  TEST(StringAllocation) {
    InitializeVM();
  
  
    const unsigned char chars[] = { 0xe5, 0xa4, 0xa7 };
    for (int length = 0; length < 100; length++) {
      v8::HandleScope scope;
      char* non_ascii = NewArray<char>(3 * length + 1);
      char* ascii = NewArray<char>(length + 1);
      non_ascii[3 * length] = 0;
      ascii[length] = 0;
      for (int i = 0; i < length; i++) {
        ascii[i] = 'a';
        non_ascii[3 * i] = chars[0];
        non_ascii[3 * i + 1] = chars[1];
        non_ascii[3 * i + 2] = chars[2];
      }
      Handle<String> non_ascii_sym =
          FACTORY->LookupSymbol(Vector<const char>(non_ascii, 3 * length));
      CHECK_EQ(length, non_ascii_sym->length());
      Handle<String> ascii_sym =
          FACTORY->LookupSymbol(Vector<const char>(ascii, length));
      CHECK_EQ(length, ascii_sym->length());
      Handle<String> non_ascii_str =
          FACTORY->NewStringFromUtf8(Vector<const char>(non_ascii, 3 * length));
      non_ascii_str->Hash();
      CHECK_EQ(length, non_ascii_str->length());
      Handle<String> ascii_str =
          FACTORY->NewStringFromUtf8(Vector<const char>(ascii, length));
      ascii_str->Hash();
      CHECK_EQ(length, ascii_str->length());
      DeleteArray(non_ascii);
      DeleteArray(ascii);
    }
  }
  
  
  static int ObjectsFoundInHeap(Handle<Object> objs[], int size) {
    // Count the number of objects found in the heap.
    int found_count = 0;
    HeapIterator iterator;
    for (HeapObject* obj = iterator.next(); obj != NULL; obj = iterator.next()) {
      for (int i = 0; i < size; i++) {
        if (*objs[i] == obj) {
          found_count++;
        }
      }
    }
    return found_count;
  }
  
  
  TEST(Iteration) {
    InitializeVM();
    v8::HandleScope scope;
  
    // Array of objects to scan haep for.
    const int objs_count = 6;
    Handle<Object> objs[objs_count];
    int next_objs_index = 0;
  
    // Allocate a JS array to OLD_POINTER_SPACE and NEW_SPACE
    objs[next_objs_index++] = FACTORY->NewJSArray(10);
    objs[next_objs_index++] = FACTORY->NewJSArray(10, TENURED);
  
    // Allocate a small string to OLD_DATA_SPACE and NEW_SPACE
    objs[next_objs_index++] =
        FACTORY->NewStringFromAscii(CStrVector("abcdefghij"));
    objs[next_objs_index++] =
        FACTORY->NewStringFromAscii(CStrVector("abcdefghij"), TENURED);
  
    // Allocate a large string (for large object space).
    int large_size = HEAP->MaxObjectSizeInPagedSpace() + 1;
    char* str = new char[large_size];
    for (int i = 0; i < large_size - 1; ++i) str[i] = 'a';
    str[large_size - 1] = '\0';
    objs[next_objs_index++] =
        FACTORY->NewStringFromAscii(CStrVector(str), TENURED);
    delete[] str;
  
    // Add a Map object to look for.
    objs[next_objs_index++] = Handle<Map>(HeapObject::cast(*objs[0])->map());
  
    CHECK_EQ(objs_count, next_objs_index);
    CHECK_EQ(objs_count, ObjectsFoundInHeap(objs, objs_count));
  }
  
  
  TEST(LargeObjectSpaceContains) {
    InitializeVM();
  
    HEAP->CollectGarbage(NEW_SPACE);
  
    Address current_top = HEAP->new_space()->top();
    Page* page = Page::FromAddress(current_top);
    Address current_page = page->address();
    Address next_page = current_page + Page::kPageSize;
    int bytes_to_page = static_cast<int>(next_page - current_top);
    if (bytes_to_page <= FixedArray::kHeaderSize) {
      // Alas, need to cross another page to be able to
      // put desired value.
      next_page += Page::kPageSize;
      bytes_to_page = static_cast<int>(next_page - current_top);
    }
    CHECK(bytes_to_page > FixedArray::kHeaderSize);
  
    intptr_t* flags_ptr = &Page::FromAddress(next_page)->flags_;
    Address flags_addr = reinterpret_cast<Address>(flags_ptr);
  
    int bytes_to_allocate =
        static_cast<int>(flags_addr - current_top) + kPointerSize;
  
    int n_elements = (bytes_to_allocate - FixedArray::kHeaderSize) /
        kPointerSize;
    CHECK_EQ(bytes_to_allocate, FixedArray::SizeFor(n_elements));
    FixedArray* array = FixedArray::cast(
        HEAP->AllocateFixedArray(n_elements)->ToObjectChecked());
  
    int index = n_elements - 1;
    CHECK_EQ(flags_ptr,
             HeapObject::RawField(array, FixedArray::OffsetOfElementAt(index)));
    array->set(index, Smi::FromInt(0));
    // This chould have turned next page into LargeObjectPage:
    // CHECK(Page::FromAddress(next_page)->IsLargeObjectPage());
  
    HeapObject* addr = HeapObject::FromAddress(next_page + 2 * kPointerSize);
    CHECK(HEAP->new_space()->Contains(addr));
    CHECK(!HEAP->lo_space()->Contains(addr));
  }
  
  
  TEST(EmptyHandleEscapeFrom) {
    InitializeVM();
  
    v8::HandleScope scope;
    Handle<JSObject> runaway;
  
    {
        v8::HandleScope nested;
        Handle<JSObject> empty;
        runaway = empty.EscapeFrom(&nested);
    }
  
    CHECK(runaway.is_null());
  }
  
  
  static int LenFromSize(int size) {
    return (size - FixedArray::kHeaderSize) / kPointerSize;
  }
  
  
  TEST(Regression39128) {
    // Test case for crbug.com/39128.
    InitializeVM();
  
    // Increase the chance of 'bump-the-pointer' allocation in old space.
    bool force_compaction = true;
    HEAP->CollectAllGarbage(force_compaction);
  
    v8::HandleScope scope;
  
    // The plan: create JSObject which references objects in new space.
    // Then clone this object (forcing it to go into old space) and check
    // that region dirty marks are updated correctly.
  
    // Step 1: prepare a map for the object.  We add 1 inobject property to it.
    Handle<JSFunction> object_ctor(
        Isolate::Current()->global_context()->object_function());
    CHECK(object_ctor->has_initial_map());
    Handle<Map> object_map(object_ctor->initial_map());
    // Create a map with single inobject property.
    Handle<Map> my_map = FACTORY->CopyMap(object_map, 1);
    int n_properties = my_map->inobject_properties();
    CHECK_GT(n_properties, 0);
  
    int object_size = my_map->instance_size();
  
    // Step 2: allocate a lot of objects so to almost fill new space: we need
    // just enough room to allocate JSObject and thus fill the newspace.
  
    int allocation_amount = Min(FixedArray::kMaxSize,
                                HEAP->MaxObjectSizeInNewSpace());
    int allocation_len = LenFromSize(allocation_amount);
    NewSpace* new_space = HEAP->new_space();
    Address* top_addr = new_space->allocation_top_address();
    Address* limit_addr = new_space->allocation_limit_address();
    while ((*limit_addr - *top_addr) > allocation_amount) {
      CHECK(!HEAP->always_allocate());
      Object* array = HEAP->AllocateFixedArray(allocation_len)->ToObjectChecked();
      CHECK(!array->IsFailure());
      CHECK(new_space->Contains(array));
    }
  
    // Step 3: now allocate fixed array and JSObject to fill the whole new space.
    int to_fill = static_cast<int>(*limit_addr - *top_addr - object_size);
    int fixed_array_len = LenFromSize(to_fill);
    CHECK(fixed_array_len < FixedArray::kMaxLength);
  
    CHECK(!HEAP->always_allocate());
    Object* array = HEAP->AllocateFixedArray(fixed_array_len)->ToObjectChecked();
    CHECK(!array->IsFailure());
    CHECK(new_space->Contains(array));
  
    Object* object = HEAP->AllocateJSObjectFromMap(*my_map)->ToObjectChecked();
    CHECK(new_space->Contains(object));
    JSObject* jsobject = JSObject::cast(object);
    CHECK_EQ(0, FixedArray::cast(jsobject->elements())->length());
    CHECK_EQ(0, jsobject->properties()->length());
    // Create a reference to object in new space in jsobject.
    jsobject->FastPropertyAtPut(-1, array);
  
    CHECK_EQ(0, static_cast<int>(*limit_addr - *top_addr));
  
    // Step 4: clone jsobject, but force always allocate first to create a clone
    // in old pointer space.
    Address old_pointer_space_top = HEAP->old_pointer_space()->top();
    AlwaysAllocateScope aa_scope;
    Object* clone_obj = HEAP->CopyJSObject(jsobject)->ToObjectChecked();
    JSObject* clone = JSObject::cast(clone_obj);
    if (clone->address() != old_pointer_space_top) {
      // Alas, got allocated from free list, we cannot do checks.
      return;
    }
    CHECK(HEAP->old_pointer_space()->Contains(clone->address()));
  
    // Step 5: verify validity of region dirty marks.
    Address clone_addr = clone->address();
    Page* page = Page::FromAddress(clone_addr);
    // Check that region covering inobject property 1 is marked dirty.
    CHECK(page->IsRegionDirty(clone_addr + (object_size - kPointerSize)));
  }
  
  
  TEST(TestCodeFlushing) {
    i::FLAG_allow_natives_syntax = true;
    // If we do not flush code this test is invalid.
    if (!FLAG_flush_code) return;
    InitializeVM();
    v8::HandleScope scope;
    const char* source = "function foo() {"
                         "  var x = 42;"
                         "  var y = 42;"
                         "  var z = x + y;"
                         "};"
                         "foo()";
    Handle<String> foo_name = FACTORY->LookupAsciiSymbol("foo");
  
    // This compile will add the code to the compilation cache.
    { v8::HandleScope scope;
      CompileRun(source);
    }
  
    // Check function is compiled.
    Object* func_value = Isolate::Current()->context()->global()->
        GetProperty(*foo_name)->ToObjectChecked();
    CHECK(func_value->IsJSFunction());
    Handle<JSFunction> function(JSFunction::cast(func_value));
    CHECK(function->shared()->is_compiled());
  
    HEAP->CollectAllGarbage(true);
    HEAP->CollectAllGarbage(true);
  
    CHECK(function->shared()->is_compiled());
  
    HEAP->CollectAllGarbage(true);
    HEAP->CollectAllGarbage(true);
    HEAP->CollectAllGarbage(true);
    HEAP->CollectAllGarbage(true);
    HEAP->CollectAllGarbage(true);
    HEAP->CollectAllGarbage(true);
  
    // foo should no longer be in the compilation cache
    CHECK(!function->shared()->is_compiled() || function->IsOptimized());
    CHECK(!function->is_compiled() || function->IsOptimized());
    // Call foo to get it recompiled.
    CompileRun("foo()");
    CHECK(function->shared()->is_compiled());
    CHECK(function->is_compiled());
  }
  
  
  // Count the number of global contexts in the weak list of global contexts.
  static int CountGlobalContexts() {
    int count = 0;
    Object* object = HEAP->global_contexts_list();
    while (!object->IsUndefined()) {
      count++;
      object = Context::cast(object)->get(Context::NEXT_CONTEXT_LINK);
    }
    return count;
  }
  
  
  // Count the number of user functions in the weak list of optimized
  // functions attached to a global context.
  static int CountOptimizedUserFunctions(v8::Handle<v8::Context> context) {
    int count = 0;
    Handle<Context> icontext = v8::Utils::OpenHandle(*context);
    Object* object = icontext->get(Context::OPTIMIZED_FUNCTIONS_LIST);
    while (object->IsJSFunction() && !JSFunction::cast(object)->IsBuiltin()) {
      count++;
      object = JSFunction::cast(object)->next_function_link();
    }
    return count;
  }
  
  
  TEST(TestInternalWeakLists) {
    v8::V8::Initialize();
  
    static const int kNumTestContexts = 10;
  
    v8::HandleScope scope;
    v8::Persistent<v8::Context> ctx[kNumTestContexts];
  
    CHECK_EQ(0, CountGlobalContexts());
  
    // Create a number of global contests which gets linked together.
    for (int i = 0; i < kNumTestContexts; i++) {
      ctx[i] = v8::Context::New();
  
      bool opt = (FLAG_always_opt && i::V8::UseCrankshaft());
  
      CHECK_EQ(i + 1, CountGlobalContexts());
  
      ctx[i]->Enter();
  
      // Create a handle scope so no function objects get stuch in the outer
      // handle scope
      v8::HandleScope scope;
      const char* source = "function f1() { };"
                           "function f2() { };"
                           "function f3() { };"
                           "function f4() { };"
                           "function f5() { };";
      CompileRun(source);
      CHECK_EQ(0, CountOptimizedUserFunctions(ctx[i]));
      CompileRun("f1()");
      CHECK_EQ(opt ? 1 : 0, CountOptimizedUserFunctions(ctx[i]));
      CompileRun("f2()");
      CHECK_EQ(opt ? 2 : 0, CountOptimizedUserFunctions(ctx[i]));
      CompileRun("f3()");
      CHECK_EQ(opt ? 3 : 0, CountOptimizedUserFunctions(ctx[i]));
      CompileRun("f4()");
      CHECK_EQ(opt ? 4 : 0, CountOptimizedUserFunctions(ctx[i]));
      CompileRun("f5()");
      CHECK_EQ(opt ? 5 : 0, CountOptimizedUserFunctions(ctx[i]));
  
      // Remove function f1, and
      CompileRun("f1=null");
  
      // Scavenge treats these references as strong.
      for (int j = 0; j < 10; j++) {
        HEAP->PerformScavenge();
        CHECK_EQ(opt ? 5 : 0, CountOptimizedUserFunctions(ctx[i]));
      }
  
      // Mark compact handles the weak references.
      HEAP->CollectAllGarbage(true);
      CHECK_EQ(opt ? 4 : 0, CountOptimizedUserFunctions(ctx[i]));
  
      // Get rid of f3 and f5 in the same way.
      CompileRun("f3=null");
      for (int j = 0; j < 10; j++) {
        HEAP->PerformScavenge();
        CHECK_EQ(opt ? 4 : 0, CountOptimizedUserFunctions(ctx[i]));
      }
      HEAP->CollectAllGarbage(true);
      CHECK_EQ(opt ? 3 : 0, CountOptimizedUserFunctions(ctx[i]));
      CompileRun("f5=null");
      for (int j = 0; j < 10; j++) {
        HEAP->PerformScavenge();
        CHECK_EQ(opt ? 3 : 0, CountOptimizedUserFunctions(ctx[i]));
      }
      HEAP->CollectAllGarbage(true);
      CHECK_EQ(opt ? 2 : 0, CountOptimizedUserFunctions(ctx[i]));
  
      ctx[i]->Exit();
    }
  
    // Force compilation cache cleanup.
    HEAP->CollectAllGarbage(true);
  
    // Dispose the global contexts one by one.
    for (int i = 0; i < kNumTestContexts; i++) {
      ctx[i].Dispose();
      ctx[i].Clear();
  
      // Scavenge treats these references as strong.
      for (int j = 0; j < 10; j++) {
        HEAP->PerformScavenge();
        CHECK_EQ(kNumTestContexts - i, CountGlobalContexts());
      }
  
      // Mark compact handles the weak references.
      HEAP->CollectAllGarbage(true);
      CHECK_EQ(kNumTestContexts - i - 1, CountGlobalContexts());
    }
  
    CHECK_EQ(0, CountGlobalContexts());
  }
  
  
  // Count the number of global contexts in the weak list of global contexts
  // causing a GC after the specified number of elements.
  static int CountGlobalContextsWithGC(int n) {
    int count = 0;
    Handle<Object> object(HEAP->global_contexts_list());
    while (!object->IsUndefined()) {
      count++;
      if (count == n) HEAP->CollectAllGarbage(true);
      object =
          Handle<Object>(Context::cast(*object)->get(Context::NEXT_CONTEXT_LINK));
    }
    return count;
  }
  
  
  // Count the number of user functions in the weak list of optimized
  // functions attached to a global context causing a GC after the
  // specified number of elements.
  static int CountOptimizedUserFunctionsWithGC(v8::Handle<v8::Context> context,
                                               int n) {
    int count = 0;
    Handle<Context> icontext = v8::Utils::OpenHandle(*context);
    Handle<Object> object(icontext->get(Context::OPTIMIZED_FUNCTIONS_LIST));
    while (object->IsJSFunction() &&
           !Handle<JSFunction>::cast(object)->IsBuiltin()) {
      count++;
      if (count == n) HEAP->CollectAllGarbage(true);
      object = Handle<Object>(
          Object::cast(JSFunction::cast(*object)->next_function_link()));
    }
    return count;
  }
  
  
  TEST(TestInternalWeakListsTraverseWithGC) {
    v8::V8::Initialize();
  
    static const int kNumTestContexts = 10;
  
    v8::HandleScope scope;
    v8::Persistent<v8::Context> ctx[kNumTestContexts];
  
    CHECK_EQ(0, CountGlobalContexts());
  
    // Create an number of contexts and check the length of the weak list both
    // with and without GCs while iterating the list.
    for (int i = 0; i < kNumTestContexts; i++) {
      ctx[i] = v8::Context::New();
      CHECK_EQ(i + 1, CountGlobalContexts());
      CHECK_EQ(i + 1, CountGlobalContextsWithGC(i / 2 + 1));
    }
  
    bool opt = (FLAG_always_opt && i::V8::UseCrankshaft());
  
    // Compile a number of functions the length of the weak list of optimized
    // functions both with and without GCs while iterating the list.
    ctx[0]->Enter();
    const char* source = "function f1() { };"
                         "function f2() { };"
                         "function f3() { };"
                         "function f4() { };"
                         "function f5() { };";
    CompileRun(source);
    CHECK_EQ(0, CountOptimizedUserFunctions(ctx[0]));
    CompileRun("f1()");
    CHECK_EQ(opt ? 1 : 0, CountOptimizedUserFunctions(ctx[0]));
    CHECK_EQ(opt ? 1 : 0, CountOptimizedUserFunctionsWithGC(ctx[0], 1));
    CompileRun("f2()");
    CHECK_EQ(opt ? 2 : 0, CountOptimizedUserFunctions(ctx[0]));
    CHECK_EQ(opt ? 2 : 0, CountOptimizedUserFunctionsWithGC(ctx[0], 1));
    CompileRun("f3()");
    CHECK_EQ(opt ? 3 : 0, CountOptimizedUserFunctions(ctx[0]));
    CHECK_EQ(opt ? 3 : 0, CountOptimizedUserFunctionsWithGC(ctx[0], 1));
    CompileRun("f4()");
    CHECK_EQ(opt ? 4 : 0, CountOptimizedUserFunctions(ctx[0]));
    CHECK_EQ(opt ? 4 : 0, CountOptimizedUserFunctionsWithGC(ctx[0], 2));
    CompileRun("f5()");
    CHECK_EQ(opt ? 5 : 0, CountOptimizedUserFunctions(ctx[0]));
    CHECK_EQ(opt ? 5 : 0, CountOptimizedUserFunctionsWithGC(ctx[0], 4));
  
    ctx[0]->Exit();
  }
  
  
  TEST(TestSizeOfObjectsVsHeapIteratorPrecision) {
    InitializeVM();
    intptr_t size_of_objects_1 = HEAP->SizeOfObjects();
    HeapIterator iterator(HeapIterator::kFilterFreeListNodes);
    intptr_t size_of_objects_2 = 0;
    for (HeapObject* obj = iterator.next();
         obj != NULL;
         obj = iterator.next()) {
      size_of_objects_2 += obj->Size();
    }
    // Delta must be within 1% of the larger result.
    if (size_of_objects_1 > size_of_objects_2) {
      intptr_t delta = size_of_objects_1 - size_of_objects_2;
      PrintF("Heap::SizeOfObjects: %" V8_PTR_PREFIX "d, "
             "Iterator: %" V8_PTR_PREFIX "d, "
             "delta: %" V8_PTR_PREFIX "d\n",
             size_of_objects_1, size_of_objects_2, delta);
      CHECK_GT(size_of_objects_1 / 100, delta);
    } else {
      intptr_t delta = size_of_objects_2 - size_of_objects_1;
      PrintF("Heap::SizeOfObjects: %" V8_PTR_PREFIX "d, "
             "Iterator: %" V8_PTR_PREFIX "d, "
             "delta: %" V8_PTR_PREFIX "d\n",
             size_of_objects_1, size_of_objects_2, delta);
      CHECK_GT(size_of_objects_2 / 100, delta);
    }
  }
  
  
  class HeapIteratorTestHelper {
   public:
    HeapIteratorTestHelper(Object* a, Object* b)
        : a_(a), b_(b), a_found_(false), b_found_(false) {}
    bool a_found() { return a_found_; }
    bool b_found() { return b_found_; }
    void IterateHeap(HeapIterator::HeapObjectsFiltering mode) {
      HeapIterator iterator(mode);
      for (HeapObject* obj = iterator.next();
           obj != NULL;
           obj = iterator.next()) {
        if (obj == a_)
          a_found_ = true;
        else if (obj == b_)
          b_found_ = true;
      }
    }
   private:
    Object* a_;
    Object* b_;
    bool a_found_;
    bool b_found_;
  };
  
  TEST(HeapIteratorFilterUnreachable) {
    InitializeVM();
    v8::HandleScope scope;
    CompileRun("a = {}; b = {};");
    v8::Handle<Object> a(ISOLATE->context()->global()->GetProperty(
        *FACTORY->LookupAsciiSymbol("a"))->ToObjectChecked());
    v8::Handle<Object> b(ISOLATE->context()->global()->GetProperty(
        *FACTORY->LookupAsciiSymbol("b"))->ToObjectChecked());
    CHECK_NE(*a, *b);
    {
      HeapIteratorTestHelper helper(*a, *b);
      helper.IterateHeap(HeapIterator::kFilterUnreachable);
      CHECK(helper.a_found());
      CHECK(helper.b_found());
    }
    CHECK(ISOLATE->context()->global()->DeleteProperty(
        *FACTORY->LookupAsciiSymbol("a"), JSObject::FORCE_DELETION));
    // We ensure that GC will not happen, so our raw pointer stays valid.
    AssertNoAllocation no_alloc;
    Object* a_saved = *a;
    a.Clear();
    // Verify that "a" object still resides in the heap...
    {
      HeapIteratorTestHelper helper(a_saved, *b);
      helper.IterateHeap(HeapIterator::kNoFiltering);
      CHECK(helper.a_found());
      CHECK(helper.b_found());
    }
    // ...but is now unreachable.
    {
      HeapIteratorTestHelper helper(a_saved, *b);
      helper.IterateHeap(HeapIterator::kFilterUnreachable);
      CHECK(!helper.a_found());
      CHECK(helper.b_found());
    }
  }
  