text: // Copyright 2012 the V8 project authors. All rights reserved.
  // Redistribution and use in source and binary forms, with or without
  // modification, are permitted provided that the following conditions are
  // met:
  //
  //     * Redistributions of source code must retain the above copyright
  //       notice, this list of conditions and the following disclaimer.
  //     * Redistributions in binary form must reproduce the above
  //       copyright notice, this list of conditions and the following
  //       disclaimer in the documentation and/or other materials provided
  //       with the distribution.
  //     * Neither the name of Google Inc. nor the names of its
  //       contributors may be used to endorse or promote products derived
  //       from this software without specific prior written permission.
  //
  // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  
  #include <stdlib.h>
  #include <utility>
  
  #include "src/api/api-inl.h"
  #include "src/codegen/assembler-inl.h"
  #include "src/codegen/compilation-cache.h"
  #include "src/codegen/macro-assembler-inl.h"
  #include "src/debug/debug.h"
  #include "src/deoptimizer/deoptimizer.h"
  #include "src/execution/execution.h"
  #include "src/handles/global-handles.h"
  #include "src/heap/combined-heap.h"
  #include "src/heap/factory.h"
  #include "src/heap/gc-tracer.h"
  #include "src/heap/heap-inl.h"
  #include "src/heap/incremental-marking.h"
  #include "src/heap/mark-compact.h"
  #include "src/heap/memory-reducer.h"
  #include "src/heap/remembered-set.h"
  #include "src/ic/ic.h"
  #include "src/numbers/hash-seed-inl.h"
  #include "src/objects/elements.h"
  #include "src/objects/field-type.h"
  #include "src/objects/frame-array-inl.h"
  #include "src/objects/heap-number-inl.h"
  #include "src/objects/js-array-inl.h"
  #include "src/objects/js-collection-inl.h"
  #include "src/objects/managed.h"
  #include "src/objects/objects-inl.h"
  #include "src/objects/slots.h"
  #include "src/objects/transitions.h"
  #include "src/regexp/regexp.h"
  #include "src/snapshot/snapshot.h"
  #include "src/utils/ostreams.h"
  #include "test/cctest/cctest.h"
  #include "test/cctest/heap/heap-tester.h"
  #include "test/cctest/heap/heap-utils.h"
  #include "test/cctest/test-feedback-vector.h"
  #include "test/cctest/test-transitions.h"
  
  namespace v8 {
  namespace internal {
  namespace heap {
  
  // We only start allocation-site tracking with the second instantiation.
  static const int kPretenureCreationCount =
      AllocationSite::kPretenureMinimumCreated + 1;
  
  static void CheckMap(Map map, int type, int instance_size) {
    CHECK(map.IsHeapObject());
    DCHECK(IsValidHeapObject(CcTest::heap(), map));
    CHECK_EQ(ReadOnlyRoots(CcTest::heap()).meta_map(), map.map());
    CHECK_EQ(type, map.instance_type());
    CHECK_EQ(instance_size, map.instance_size());
  }
  
  
  TEST(HeapMaps) {
    CcTest::InitializeVM();
    ReadOnlyRoots roots(CcTest::heap());
    CheckMap(roots.meta_map(), MAP_TYPE, Map::kSize);
    CheckMap(roots.heap_number_map(), HEAP_NUMBER_TYPE, HeapNumber::kSize);
    CheckMap(roots.fixed_array_map(), FIXED_ARRAY_TYPE, kVariableSizeSentinel);
    CheckMap(roots.hash_table_map(), HASH_TABLE_TYPE, kVariableSizeSentinel);
    CheckMap(roots.string_map(), STRING_TYPE, kVariableSizeSentinel);
  }
  
  static void VerifyStoredPrototypeMap(Isolate* isolate,
                                       int stored_map_context_index,
                                       int stored_ctor_context_index) {
    Handle<Context> context = isolate->native_context();
  
    Handle<Map> this_map(Map::cast(context->get(stored_map_context_index)),
                         isolate);
  
    Handle<JSFunction> fun(
        JSFunction::cast(context->get(stored_ctor_context_index)), isolate);
    Handle<JSObject> proto(JSObject::cast(fun->initial_map().prototype()),
                           isolate);
    Handle<Map> that_map(proto->map(), isolate);
  
    CHECK(proto->HasFastProperties());
    CHECK_EQ(*this_map, *that_map);
  }
  
  // Checks that critical maps stored on the context (mostly used for fast-path
  // checks) are unchanged after initialization.
  TEST(ContextMaps) {
    CcTest::InitializeVM();
    Isolate* isolate = CcTest::i_isolate();
    HandleScope handle_scope(isolate);
  
    VerifyStoredPrototypeMap(isolate,
                             Context::STRING_FUNCTION_PROTOTYPE_MAP_INDEX,
                             Context::STRING_FUNCTION_INDEX);
    VerifyStoredPrototypeMap(isolate, Context::REGEXP_PROTOTYPE_MAP_INDEX,
                             Context::REGEXP_FUNCTION_INDEX);
  }
  
  TEST(InitialObjects) {
    LocalContext env;
    HandleScope scope(CcTest::i_isolate());
    Handle<Context> context = v8::Utils::OpenHandle(*env);
    // Initial ArrayIterator prototype.
    CHECK_EQ(
        context->initial_array_iterator_prototype(),
        *v8::Utils::OpenHandle(*CompileRun("[][Symbol.iterator]().__proto__")));
    // Initial Array prototype.
    CHECK_EQ(context->initial_array_prototype(),
             *v8::Utils::OpenHandle(*CompileRun("Array.prototype")));
    // Initial Generator prototype.
    CHECK_EQ(context->initial_generator_prototype(),
             *v8::Utils::OpenHandle(
                 *CompileRun("(function*(){}).__proto__.prototype")));
    // Initial Iterator prototype.
    CHECK_EQ(context->initial_iterator_prototype(),
             *v8::Utils::OpenHandle(
                 *CompileRun("[][Symbol.iterator]().__proto__.__proto__")));
    // Initial Object prototype.
    CHECK_EQ(context->initial_object_prototype(),
             *v8::Utils::OpenHandle(*CompileRun("Object.prototype")));
  }
  
  static void CheckOddball(Isolate* isolate, Object obj, const char* string) {
    CHECK(obj.IsOddball());
    Handle<Object> handle(obj, isolate);
    Object print_string = *Object::ToString(isolate, handle).ToHandleChecked();
    CHECK(String::cast(print_string).IsOneByteEqualTo(CStrVector(string)));
  }
  
  static void CheckSmi(Isolate* isolate, int value, const char* string) {
    Handle<Object> handle(Smi::FromInt(value), isolate);
    Object print_string = *Object::ToString(isolate, handle).ToHandleChecked();
    CHECK(String::cast(print_string).IsOneByteEqualTo(CStrVector(string)));
  }
  
  
  static void CheckNumber(Isolate* isolate, double value, const char* string) {
    Handle<Object> number = isolate->factory()->NewNumber(value);
    CHECK(number->IsNumber());
    Handle<Object> print_string =
        Object::ToString(isolate, number).ToHandleChecked();
    CHECK(String::cast(*print_string).IsOneByteEqualTo(CStrVector(string)));
  }
  
  void CheckEmbeddedObjectsAreEqual(Handle<Code> lhs, Handle<Code> rhs) {
    int mode_mask = RelocInfo::ModeMask(RelocInfo::FULL_EMBEDDED_OBJECT);
    RelocIterator lhs_it(*lhs, mode_mask);
    RelocIterator rhs_it(*rhs, mode_mask);
    while (!lhs_it.done() && !rhs_it.done()) {
      CHECK(lhs_it.rinfo()->target_object() == rhs_it.rinfo()->target_object());
  
      lhs_it.next();
      rhs_it.next();
    }
    CHECK(lhs_it.done() == rhs_it.done());
  }
  
  HEAP_TEST(TestNewSpaceRefsInCopiedCode) {
    CcTest::InitializeVM();
    Isolate* isolate = CcTest::i_isolate();
    Factory* factory = isolate->factory();
    HandleScope sc(isolate);
  
    Handle<HeapNumber> value = factory->NewHeapNumber(1.000123);
    CHECK(Heap::InYoungGeneration(*value));
  
    i::byte buffer[i::Assembler::kMinimalBufferSize];
    MacroAssembler masm(isolate, v8::internal::CodeObjectRequired::kYes,
                        ExternalAssemblerBuffer(buffer, sizeof(buffer)));
    // Add a new-space reference to the code.
    masm.Push(value);
  
    CodeDesc desc;
    masm.GetCode(isolate, &desc);
    Handle<Code> code = Factory::CodeBuilder(isolate, desc, Code::STUB).Build();
  
    Handle<Code> copy;
    {
      CodeSpaceMemoryModificationScope modification_scope(isolate->heap());
      copy = factory->CopyCode(code);
    }
  
    CheckEmbeddedObjectsAreEqual(code, copy);
    CcTest::CollectAllAvailableGarbage();
    CheckEmbeddedObjectsAreEqual(code, copy);
  }
  
  static void CheckFindCodeObject(Isolate* isolate) {
    // Test FindCodeObject
  #define __ assm.
  
    Assembler assm(AssemblerOptions{});
  
    __ nop();  // supported on all architectures
  
    CodeDesc desc;
    assm.GetCode(isolate, &desc);
    Handle<Code> code = Factory::CodeBuilder(isolate, desc, Code::STUB).Build();
    CHECK(code->IsCode());
  
    HeapObject obj = HeapObject::cast(*code);
    Address obj_addr = obj.address();
  
    for (int i = 0; i < obj.Size(); i += kTaggedSize) {
      Object found = isolate->FindCodeObject(obj_addr + i);
      CHECK_EQ(*code, found);
    }
  
    Handle<Code> copy = Factory::CodeBuilder(isolate, desc, Code::STUB).Build();
    HeapObject obj_copy = HeapObject::cast(*copy);
    Object not_right =
        isolate->FindCodeObject(obj_copy.address() + obj_copy.Size() / 2);
    CHECK(not_right != *code);
  }
  
  
  TEST(HandleNull) {
    CcTest::InitializeVM();
    Isolate* isolate = CcTest::i_isolate();
    HandleScope outer_scope(isolate);
    LocalContext context;
    Handle<Object> n(Object(0), isolate);
    CHECK(!n.is_null());
  }
  
  
  TEST(HeapObjects) {
    CcTest::InitializeVM();
    Isolate* isolate = CcTest::i_isolate();
    Factory* factory = isolate->factory();
    Heap* heap = isolate->heap();
  
    HandleScope sc(isolate);
    Handle<Object> value = factory->NewNumber(1.000123);
    CHECK(value->IsHeapNumber());
    CHECK(value->IsNumber());
    CHECK_EQ(1.000123, value->Number());
  
    value = factory->NewNumber(1.0);
    CHECK(value->IsSmi());
    CHECK(value->IsNumber());
    CHECK_EQ(1.0, value->Number());
  
    value = factory->NewNumberFromInt(1024);
    CHECK(value->IsSmi());
    CHECK(value->IsNumber());
    CHECK_EQ(1024.0, value->Number());
  
    value = factory->NewNumberFromInt(Smi::kMinValue);
    CHECK(value->IsSmi());
    CHECK(value->IsNumber());
    CHECK_EQ(Smi::kMinValue, Handle<Smi>::cast(value)->value());
  
    value = factory->NewNumberFromInt(Smi::kMaxValue);
    CHECK(value->IsSmi());
    CHECK(value->IsNumber());
    CHECK_EQ(Smi::kMaxValue, Handle<Smi>::cast(value)->value());
  
  #if !defined(V8_TARGET_ARCH_64_BIT)
    // TODO(lrn): We need a NumberFromIntptr function in order to test this.
    value = factory->NewNumberFromInt(Smi::kMinValue - 1);
    CHECK(value->IsHeapNumber());
    CHECK(value->IsNumber());
    CHECK_EQ(static_cast<double>(Smi::kMinValue - 1), value->Number());
  #endif
  
    value = factory->NewNumberFromUint(static_cast<uint32_t>(Smi::kMaxValue) + 1);
    CHECK(value->IsHeapNumber());
    CHECK(value->IsNumber());
    CHECK_EQ(static_cast<double>(static_cast<uint32_t>(Smi::kMaxValue) + 1),
             value->Number());
  
    value = factory->NewNumberFromUint(static_cast<uint32_t>(1) << 31);
    CHECK(value->IsHeapNumber());
    CHECK(value->IsNumber());
    CHECK_EQ(static_cast<double>(static_cast<uint32_t>(1) << 31),
             value->Number());
  
    // nan oddball checks
    CHECK(factory->nan_value()->IsNumber());
    CHECK(std::isnan(factory->nan_value()->Number()));
  
    Handle<String> s = factory->NewStringFromStaticChars("fisk hest ");
    CHECK(s->IsString());
    CHECK_EQ(10, s->length());
  
    Handle<String> object_string = Handle<String>::cast(factory->Object_string());
    Handle<JSGlobalObject> global(CcTest::i_isolate()->context().global_object(),
                                  isolate);
    CHECK(Just(true) == JSReceiver::HasOwnProperty(global, object_string));
  
    // Check ToString for oddballs
    ReadOnlyRoots roots(heap);
    CheckOddball(isolate, roots.true_value(), "true");
    CheckOddball(isolate, roots.false_value(), "false");
    CheckOddball(isolate, roots.null_value(), "null");
    CheckOddball(isolate, roots.undefined_value(), "undefined");
  
    // Check ToString for Smis
    CheckSmi(isolate, 0, "0");
    CheckSmi(isolate, 42, "42");
    CheckSmi(isolate, -42, "-42");
  
    // Check ToString for Numbers
    CheckNumber(isolate, 1.1, "1.1");
  
    CheckFindCodeObject(isolate);
  }
  
  TEST(Tagging) {
    CcTest::InitializeVM();
    int request = 24;
    CHECK_EQ(request, static_cast<int>(OBJECT_POINTER_ALIGN(request)));
    CHECK(Smi::FromInt(42).IsSmi());
    CHECK(Smi::FromInt(Smi::kMinValue).IsSmi());
    CHECK(Smi::FromInt(Smi::kMaxValue).IsSmi());
  }
  
  
  TEST(GarbageCollection) {
    CcTest::InitializeVM();
    Isolate* isolate = CcTest::i_isolate();
    Factory* factory = isolate->factory();
  
    HandleScope sc(isolate);
    // Check GC.
    CcTest::CollectGarbage(NEW_SPACE);
  
    Handle<JSGlobalObject> global(CcTest::i_isolate()->context().global_object(),
                                  isolate);
    Handle<String> name = factory->InternalizeUtf8String("theFunction");
    Handle<String> prop_name = factory->InternalizeUtf8String("theSlot");
    Handle<String> prop_namex = factory->InternalizeUtf8String("theSlotx");
    Handle<String> obj_name = factory->InternalizeUtf8String("theObject");
    Handle<Smi> twenty_three(Smi::FromInt(23), isolate);
    Handle<Smi> twenty_four(Smi::FromInt(24), isolate);
  
    {
      HandleScope inner_scope(isolate);
      // Allocate a function and keep it in global object's property.
      Handle<JSFunction> function = factory->NewFunctionForTest(name);
      Object::SetProperty(isolate, global, name, function).Check();
      // Allocate an object.  Unrooted after leaving the scope.
      Handle<JSObject> obj = factory->NewJSObject(function);
      Object::SetProperty(isolate, obj, prop_name, twenty_three).Check();
      Object::SetProperty(isolate, obj, prop_namex, twenty_four).Check();
  
      CHECK_EQ(Smi::FromInt(23),
               *Object::GetProperty(isolate, obj, prop_name).ToHandleChecked());
      CHECK_EQ(Smi::FromInt(24),
               *Object::GetProperty(isolate, obj, prop_namex).ToHandleChecked());
    }
  
    CcTest::CollectGarbage(NEW_SPACE);
  
    // Function should be alive.
    CHECK(Just(true) == JSReceiver::HasOwnProperty(global, name));
    // Check function is retained.
    Handle<Object> func_value =
        Object::GetProperty(isolate, global, name).ToHandleChecked();
    CHECK(func_value->IsJSFunction());
    Handle<JSFunction> function = Handle<JSFunction>::cast(func_value);
  
    {
      HandleScope inner_scope(isolate);
      // Allocate another object, make it reachable from global.
      Handle<JSObject> obj = factory->NewJSObject(function);
      Object::SetProperty(isolate, global, obj_name, obj).Check();
      Object::SetProperty(isolate, obj, prop_name, twenty_three).Check();
    }
  
    // After gc, it should survive.
    CcTest::CollectGarbage(NEW_SPACE);
  
    CHECK(Just(true) == JSReceiver::HasOwnProperty(global, obj_name));
    Handle<Object> obj =
        Object::GetProperty(isolate, global, obj_name).ToHandleChecked();
    CHECK(obj->IsJSObject());
    CHECK_EQ(Smi::FromInt(23),
             *Object::GetProperty(isolate, obj, prop_name).ToHandleChecked());
  }
  
  
  static void VerifyStringAllocation(Isolate* isolate, const char* string) {
    HandleScope scope(isolate);
    Handle<String> s = isolate->factory()->NewStringFromUtf8(
        CStrVector(string)).ToHandleChecked();
    CHECK_EQ(strlen(string), s->length());
    for (int index = 0; index < s->length(); index++) {
      CHECK_EQ(static_cast<uint16_t>(string[index]), s->Get(index));
    }
  }
  
  
  TEST(String) {
    CcTest::InitializeVM();
    Isolate* isolate = reinterpret_cast<Isolate*>(CcTest::isolate());
  
    VerifyStringAllocation(isolate, "a");
    VerifyStringAllocation(isolate, "ab");
    VerifyStringAllocation(isolate, "abc");
    VerifyStringAllocation(isolate, "abcd");
    VerifyStringAllocation(isolate, "fiskerdrengen er paa havet");
  }
  
  
  TEST(LocalHandles) {
    CcTest::InitializeVM();
    Isolate* isolate = CcTest::i_isolate();
    Factory* factory = isolate->factory();
  
    v8::HandleScope scope(CcTest::isolate());
    const char* name = "Kasper the spunky";
    Handle<String> string = factory->NewStringFromAsciiChecked(name);
    CHECK_EQ(strlen(name), string->length());
  }
  
  
  TEST(GlobalHandles) {
    CcTest::InitializeVM();
    Isolate* isolate = CcTest::i_isolate();
    Factory* factory = isolate->factory();
    GlobalHandles* global_handles = isolate->global_handles();
  
    Handle<Object> h1;
    Handle<Object> h2;
    Handle<Object> h3;
    Handle<Object> h4;
  
    {
      HandleScope scope(isolate);
  
      Handle<Object> i = factory->NewStringFromStaticChars("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
    CcTest::CollectGarbage(NEW_SPACE);
  
    CHECK((*h1).IsString());
    CHECK((*h2).IsHeapNumber());
    CHECK((*h3).IsString());
    CHECK((*h4).IsHeapNumber());
  
    CHECK_EQ(*h3, *h1);
    GlobalHandles::Destroy(h1.location());
    GlobalHandles::Destroy(h3.location());
  
    CHECK_EQ(*h4, *h2);
    GlobalHandles::Destroy(h2.location());
    GlobalHandles::Destroy(h4.location());
  }
  
  
  static bool WeakPointerCleared = false;
  
  static void TestWeakGlobalHandleCallback(
      const v8::WeakCallbackInfo<void>& data) {
    std::pair<v8::Persistent<v8::Value>*, int>* p =
        reinterpret_cast<std::pair<v8::Persistent<v8::Value>*, int>*>(
            data.GetParameter());
    if (p->second == 1234) WeakPointerCleared = true;
    p->first->Reset();
  }
  
  TEST(WeakGlobalUnmodifiedApiHandlesScavenge) {
    CcTest::InitializeVM();
    Isolate* isolate = CcTest::i_isolate();
    LocalContext context;
    Factory* factory = isolate->factory();
    GlobalHandles* global_handles = isolate->global_handles();
  
    WeakPointerCleared = false;
  
    Handle<Object> h1;
    Handle<Object> h2;
  
    {
      HandleScope scope(isolate);
  
      // Create an Api object that is unmodified.
      Local<v8::Function> function = FunctionTemplate::New(context->GetIsolate())
                                         ->GetFunction(context.local())
                                         .ToLocalChecked();
      Local<v8::Object> i =
          function->NewInstance(context.local()).ToLocalChecked();
      Handle<Object> u = factory->NewNumber(1.12344);
  
      h1 = global_handles->Create(*u);
      h2 = global_handles->Create(*(reinterpret_cast<internal::Address*>(*i)));
    }
  
    std::pair<Handle<Object>*, int> handle_and_id(&h2, 1234);
    GlobalHandles::MakeWeak(
        h2.location(), reinterpret_cast<void*>(&handle_and_id),
        &TestWeakGlobalHandleCallback, v8::WeakCallbackType::kParameter);
  
    CcTest::CollectGarbage(NEW_SPACE);
    CHECK((*h1).IsHeapNumber());
    CHECK(WeakPointerCleared);
    GlobalHandles::Destroy(h1.location());
  }
  
  TEST(WeakGlobalHandlesMark) {
    FLAG_stress_incremental_marking = false;
    CcTest::InitializeVM();
    Isolate* isolate = CcTest::i_isolate();
    Factory* factory = isolate->factory();
    GlobalHandles* global_handles = isolate->global_handles();
  
    WeakPointerCleared = false;
  
    Handle<Object> h1;
    Handle<Object> h2;
  
    {
      HandleScope scope(isolate);
  
      Handle<Object> i = factory->NewStringFromStaticChars("fisk");
      Handle<Object> u = factory->NewNumber(1.12344);
  
      h1 = global_handles->Create(*i);
      h2 = global_handles->Create(*u);
    }
  
    // Make sure the objects are promoted.
    CcTest::CollectGarbage(OLD_SPACE);
    CcTest::CollectGarbage(NEW_SPACE);
    CHECK(!Heap::InYoungGeneration(*h1) && !Heap::InYoungGeneration(*h2));
  
    std::pair<Handle<Object>*, int> handle_and_id(&h2, 1234);
    GlobalHandles::MakeWeak(
        h2.location(), reinterpret_cast<void*>(&handle_and_id),
        &TestWeakGlobalHandleCallback, v8::WeakCallbackType::kParameter);
  
    // Incremental marking potentially marked handles before they turned weak.
    CcTest::CollectAllGarbage();
    CHECK((*h1).IsString());
    CHECK(WeakPointerCleared);
    GlobalHandles::Destroy(h1.location());
  }
  
  
  TEST(DeleteWeakGlobalHandle) {
    FLAG_stress_compaction = false;
    FLAG_stress_incremental_marking = false;
    CcTest::InitializeVM();
    Isolate* isolate = CcTest::i_isolate();
    Factory* factory = isolate->factory();
    GlobalHandles* global_handles = isolate->global_handles();
  
    WeakPointerCleared = false;
    Handle<Object> h;
    {
      HandleScope scope(isolate);
  
      Handle<Object> i = factory->NewStringFromStaticChars("fisk");
      h = global_handles->Create(*i);
    }
  
    std::pair<Handle<Object>*, int> handle_and_id(&h, 1234);
    GlobalHandles::MakeWeak(h.location(), reinterpret_cast<void*>(&handle_and_id),
                            &TestWeakGlobalHandleCallback,
                            v8::WeakCallbackType::kParameter);
    CHECK(!WeakPointerCleared);
    CcTest::CollectGarbage(OLD_SPACE);
    CHECK(WeakPointerCleared);
  }
  
  TEST(BytecodeArray) {
    if (FLAG_never_compact) return;
    static const uint8_t kRawBytes[] = {0xC3, 0x7E, 0xA5, 0x5A};
    static const int kRawBytesSize = sizeof(kRawBytes);
    static const int32_t kFrameSize = 32;
    static const int32_t kParameterCount = 2;
  
    ManualGCScope manual_gc_scope;
    FLAG_manual_evacuation_candidates_selection = true;
    CcTest::InitializeVM();
    Isolate* isolate = CcTest::i_isolate();
    Heap* heap = isolate->heap();
    Factory* factory = isolate->factory();
    HandleScope scope(isolate);
  
    heap::SimulateFullSpace(heap->old_space());
    Handle<FixedArray> constant_pool =
        factory->NewFixedArray(5, AllocationType::kOld);
    for (int i = 0; i < 5; i++) {
      Handle<Object> number = factory->NewHeapNumber(i);
      constant_pool->set(i, *number);
    }
  
    // Allocate and initialize BytecodeArray
    Handle<BytecodeArray> array = factory->NewBytecodeArray(
        kRawBytesSize, kRawBytes, kFrameSize, kParameterCount, constant_pool);
  
    CHECK(array->IsBytecodeArray());
    CHECK_EQ(array->length(), (int)sizeof(kRawBytes));
    CHECK_EQ(array->frame_size(), kFrameSize);
    CHECK_EQ(array->parameter_count(), kParameterCount);
    CHECK_EQ(array->constant_pool(), *constant_pool);
    CHECK_LE(array->address(), array->GetFirstBytecodeAddress());
    CHECK_GE(array->address() + array->BytecodeArraySize(),
             array->GetFirstBytecodeAddress() + array->length());
    for (int i = 0; i < kRawBytesSize; i++) {
      CHECK_EQ(Memory<uint8_t>(array->GetFirstBytecodeAddress() + i),
               kRawBytes[i]);
      CHECK_EQ(array->get(i), kRawBytes[i]);
    }
  
    FixedArray old_constant_pool_address = *constant_pool;
  
    // Perform a full garbage collection and force the constant pool to be on an
    // evacuation candidate.
    Page* evac_page = Page::FromHeapObject(*constant_pool);
    heap::ForceEvacuationCandidate(evac_page);
    CcTest::CollectAllGarbage();
  
    // BytecodeArray should survive.
    CHECK_EQ(array->length(), kRawBytesSize);
    CHECK_EQ(array->frame_size(), kFrameSize);
    for (int i = 0; i < kRawBytesSize; i++) {
      CHECK_EQ(array->get(i), kRawBytes[i]);
      CHECK_EQ(Memory<uint8_t>(array->GetFirstBytecodeAddress() + i),
               kRawBytes[i]);
    }
  
    // Constant pool should have been migrated.
    CHECK_EQ(array->constant_pool(), *constant_pool);
    CHECK_NE(array->constant_pool(), old_constant_pool_address);
  }
  
  TEST(BytecodeArrayAging) {
    static const uint8_t kRawBytes[] = {0xC3, 0x7E, 0xA5, 0x5A};
    static const int kRawBytesSize = sizeof(kRawBytes);
    static const int32_t kFrameSize = 32;
    static const int32_t kParameterCount = 2;
    CcTest::InitializeVM();
    Isolate* isolate = CcTest::i_isolate();
    Factory* factory = isolate->factory();
    HandleScope scope(isolate);
  
    Handle<BytecodeArray> array =
        factory->NewBytecodeArray(kRawBytesSize, kRawBytes, kFrameSize,
                                  kParameterCount, factory->empty_fixed_array());
  
    CHECK_EQ(BytecodeArray::kFirstBytecodeAge, array->bytecode_age());
    array->MakeOlder();
    CHECK_EQ(BytecodeArray::kQuadragenarianBytecodeAge, array->bytecode_age());
    array->set_bytecode_age(BytecodeArray::kLastBytecodeAge);
    array->MakeOlder();
    CHECK_EQ(BytecodeArray::kLastBytecodeAge, array->bytecode_age());
  }
  
  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",
    nullptr
  };
  
  static void CheckInternalizedStrings(const char** strings) {
    Isolate* isolate = CcTest::i_isolate();
    Factory* factory = isolate->factory();
    for (const char* string = *strings; *strings != nullptr;
         string = *strings++) {
      HandleScope scope(isolate);
      Handle<String> a =
          isolate->factory()->InternalizeUtf8String(CStrVector(string));
      // InternalizeUtf8String may return a failure if a GC is needed.
      CHECK(a->IsInternalizedString());
      Handle<String> b = factory->InternalizeUtf8String(string);
      CHECK_EQ(*b, *a);
      CHECK(b->IsOneByteEqualTo(CStrVector(string)));
      b = isolate->factory()->InternalizeUtf8String(CStrVector(string));
      CHECK_EQ(*b, *a);
      CHECK(b->IsOneByteEqualTo(CStrVector(string)));
    }
  }
  
  
  TEST(StringTable) {
    CcTest::InitializeVM();
  
    v8::HandleScope sc(CcTest::isolate());
    CheckInternalizedStrings(not_so_random_string_table);
    CheckInternalizedStrings(not_so_random_string_table);
  }
  
  
  TEST(FunctionAllocation) {
    CcTest::InitializeVM();
    Isolate* isolate = CcTest::i_isolate();
    Factory* factory = isolate->factory();
  
    v8::HandleScope sc(CcTest::isolate());
    Handle<String> name = factory->InternalizeUtf8String("theFunction");
    Handle<JSFunction> function = factory->NewFunctionForTest(name);
  
    Handle<Smi> twenty_three(Smi::FromInt(23), isolate);
    Handle<Smi> twenty_four(Smi::FromInt(24), isolate);
  
    Handle<String> prop_name = factory->InternalizeUtf8String("theSlot");
    Handle<JSObject> obj = factory->NewJSObject(function);
    Object::SetProperty(isolate, obj, prop_name, twenty_three).Check();
    CHECK_EQ(Smi::FromInt(23),
             *Object::GetProperty(isolate, obj, prop_name).ToHandleChecked());
    // Check that we can add properties to function objects.
    Object::SetProperty(isolate, function, prop_name, twenty_four).Check();
    CHECK_EQ(
        Smi::FromInt(24),
        *Object::GetProperty(isolate, function, prop_name).ToHandleChecked());
  }
  
  
  TEST(ObjectProperties) {
    CcTest::InitializeVM();
    Isolate* isolate = CcTest::i_isolate();
    Factory* factory = isolate->factory();
  
    v8::HandleScope sc(CcTest::isolate());
    Handle<String> object_string(
        String::cast(ReadOnlyRoots(CcTest::heap()).Object_string()), isolate);
    Handle<Object> object =
        Object::GetProperty(isolate, CcTest::i_isolate()->global_object(),
                            object_string)
            .ToHandleChecked();
    Handle<JSFunction> constructor = Handle<JSFunction>::cast(object);
    Handle<JSObject> obj = factory->NewJSObject(constructor);
    Handle<String> first = factory->InternalizeUtf8String("first");
    Handle<String> second = factory->InternalizeUtf8String("second");
  
    Handle<Smi> one(Smi::FromInt(1), isolate);
    Handle<Smi> two(Smi::FromInt(2), isolate);
  
    // check for empty
    CHECK(Just(false) == JSReceiver::HasOwnProperty(obj, first));
  
    // add first
    Object::SetProperty(isolate, obj, first, one).Check();
    CHECK(Just(true) == JSReceiver::HasOwnProperty(obj, first));
  
    // delete first
    CHECK(Just(true) ==
          JSReceiver::DeleteProperty(obj, first, LanguageMode::kSloppy));
    CHECK(Just(false) == JSReceiver::HasOwnProperty(obj, first));
  
    // add first and then second
    Object::SetProperty(isolate, obj, first, one).Check();
    Object::SetProperty(isolate, obj, second, two).Check();
    CHECK(Just(true) == JSReceiver::HasOwnProperty(obj, first));
    CHECK(Just(true) == JSReceiver::HasOwnProperty(obj, second));
  
    // delete first and then second
    CHECK(Just(true) ==
          JSReceiver::DeleteProperty(obj, first, LanguageMode::kSloppy));
    CHECK(Just(true) == JSReceiver::HasOwnProperty(obj, second));
    CHECK(Just(true) ==
          JSReceiver::DeleteProperty(obj, second, LanguageMode::kSloppy));
    CHECK(Just(false) == JSReceiver::HasOwnProperty(obj, first));
    CHECK(Just(false) == JSReceiver::HasOwnProperty(obj, second));
  
    // add first and then second
    Object::SetProperty(isolate, obj, first, one).Check();
    Object::SetProperty(isolate, obj, second, two).Check();
    CHECK(Just(true) == JSReceiver::HasOwnProperty(obj, first));
    CHECK(Just(true) == JSReceiver::HasOwnProperty(obj, second));
  
    // delete second and then first
    CHECK(Just(true) ==
          JSReceiver::DeleteProperty(obj, second, LanguageMode::kSloppy));
    CHECK(Just(true) == JSReceiver::HasOwnProperty(obj, first));
    CHECK(Just(true) ==
          JSReceiver::DeleteProperty(obj, first, LanguageMode::kSloppy));
    CHECK(Just(false) == JSReceiver::HasOwnProperty(obj, first));
    CHECK(Just(false) == JSReceiver::HasOwnProperty(obj, second));
  
    // check string and internalized string match
    const char* string1 = "fisk";
    Handle<String> s1 = factory->NewStringFromAsciiChecked(string1);
    Object::SetProperty(isolate, obj, s1, one).Check();
    Handle<String> s1_string = factory->InternalizeUtf8String(string1);
    CHECK(Just(true) == JSReceiver::HasOwnProperty(obj, s1_string));
  
    // check internalized string and string match
    const char* string2 = "fugl";
    Handle<String> s2_string = factory->InternalizeUtf8String(string2);
    Object::SetProperty(isolate, obj, s2_string, one).Check();
    Handle<String> s2 = factory->NewStringFromAsciiChecked(string2);
    CHECK(Just(true) == JSReceiver::HasOwnProperty(obj, s2));
  }
  
  
  TEST(JSObjectMaps) {
    CcTest::InitializeVM();
    Isolate* isolate = CcTest::i_isolate();
    Factory* factory = isolate->factory();
  
    v8::HandleScope sc(CcTest::isolate());
    Handle<String> name = factory->InternalizeUtf8String("theFunction");
    Handle<JSFunction> function = factory->NewFunctionForTest(name);
  
    Handle<String> prop_name = factory->InternalizeUtf8String("theSlot");
    Handle<JSObject> obj = factory->NewJSObject(function);
    Handle<Map> initial_map(function->initial_map(), isolate);
  
    // Set a propery
    Handle<Smi> twenty_three(Smi::FromInt(23), isolate);
    Object::SetProperty(isolate, obj, prop_name, twenty_three).Check();
    CHECK_EQ(Smi::FromInt(23),
             *Object::GetProperty(isolate, obj, prop_name).ToHandleChecked());
  
    // Check the map has changed
    CHECK(*initial_map != obj->map());
  }
  
  
  TEST(JSArray) {
    CcTest::InitializeVM();
    Isolate* isolate = CcTest::i_isolate();
    Factory* factory = isolate->factory();
  
    v8::HandleScope sc(CcTest::isolate());
    Handle<String> name = factory->InternalizeUtf8String("Array");
    Handle<Object> fun_obj =
        Object::GetProperty(isolate, CcTest::i_isolate()->global_object(), name)
            .ToHandleChecked();
    Handle<JSFunction> function = Handle<JSFunction>::cast(fun_obj);
  
    // Allocate the object.
    Handle<Object> element;
    Handle<JSObject> object = factory->NewJSObject(function);
    Handle<JSArray> array = Handle<JSArray>::cast(object);
    // We just initialized the VM, no heap allocation failure yet.
    JSArray::Initialize(array, 0);
  
    // Set array length to 0.
    JSArray::SetLength(array, 0);
    CHECK_EQ(Smi::kZero, array->length());
    // Must be in fast mode.
    CHECK(array->HasSmiOrObjectElements());
  
    // array[length] = name.
    Object::SetElement(isolate, array, 0, name, ShouldThrow::kDontThrow).Check();
    CHECK_EQ(Smi::FromInt(1), array->length());
    element = i::Object::GetElement(isolate, array, 0).ToHandleChecked();
    CHECK_EQ(*element, *name);
  
    // Set array length with larger than smi value.
    JSArray::SetLength(array, static_cast<uint32_t>(Smi::kMaxValue) + 1);
  
    uint32_t int_length = 0;
    CHECK(array->length().ToArrayIndex(&int_length));
    CHECK_EQ(static_cast<uint32_t>(Smi::kMaxValue) + 1, int_length);
    CHECK(array->HasDictionaryElements());  // Must be in slow mode.
  
    // array[length] = name.
    Object::SetElement(isolate, array, int_length, name, ShouldThrow::kDontThrow)
        .Check();
    uint32_t new_int_length = 0;
    CHECK(array->length().ToArrayIndex(&new_int_length));
    CHECK_EQ(static_cast<double>(int_length), new_int_length - 1);
    element = Object::GetElement(isolate, array, int_length).ToHandleChecked();
    CHECK_EQ(*element, *name);
    element = Object::GetElement(isolate, array, 0).ToHandleChecked();
    CHECK_EQ(*element, *name);
  }
  
  
  TEST(JSObjectCopy) {
    CcTest::InitializeVM();
    Isolate* isolate = CcTest::i_isolate();
    Factory* factory = isolate->factory();
  
    v8::HandleScope sc(CcTest::isolate());
    Handle<String> object_string(
        String::cast(ReadOnlyRoots(CcTest::heap()).Object_string()), isolate);
    Handle<Object> object =
        Object::GetProperty(isolate, CcTest::i_isolate()->global_object(),
                            object_string)
            .ToHandleChecked();
    Handle<JSFunction> constructor = Handle<JSFunction>::cast(object);
    Handle<JSObject> obj = factory->NewJSObject(constructor);
    Handle<String> first = factory->InternalizeUtf8String("first");
    Handle<String> second = factory->InternalizeUtf8String("second");
  
    Handle<Smi> one(Smi::FromInt(1), isolate);
    Handle<Smi> two(Smi::FromInt(2), isolate);
  
    Object::SetProperty(isolate, obj, first, one).Check();
    Object::SetProperty(isolate, obj, second, two).Check();
  
    Object::SetElement(isolate, obj, 0, first, ShouldThrow::kDontThrow).Check();
    Object::SetElement(isolate, obj, 1, second, ShouldThrow::kDontThrow).Check();
  
    // Make the clone.
    Handle<Object> value1, value2;
    Handle<JSObject> clone = factory->CopyJSObject(obj);
    CHECK(!clone.is_identical_to(obj));
  
    value1 = Object::GetElement(isolate, obj, 0).ToHandleChecked();
    value2 = Object::GetElement(isolate, clone, 0).ToHandleChecked();
    CHECK_EQ(*value1, *value2);
    value1 = Object::GetElement(isolate, obj, 1).ToHandleChecked();
    value2 = Object::GetElement(isolate, clone, 1).ToHandleChecked();
    CHECK_EQ(*value1, *value2);
  
    value1 = Object::GetProperty(isolate, obj, first).ToHandleChecked();
    value2 = Object::GetProperty(isolate, clone, first).ToHandleChecked();
    CHECK_EQ(*value1, *value2);
    value1 = Object::GetProperty(isolate, obj, second).ToHandleChecked();
    value2 = Object::GetProperty(isolate, clone, second).ToHandleChecked();
    CHECK_EQ(*value1, *value2);
  
    // Flip the values.
    Object::SetProperty(isolate, clone, first, two).Check();
    Object::SetProperty(isolate, clone, second, one).Check();
  
    Object::SetElement(isolate, clone, 0, second, ShouldThrow::kDontThrow)
        .Check();
    Object::SetElement(isolate, clone, 1, first, ShouldThrow::kDontThrow).Check();
  
    value1 = Object::GetElement(isolate, obj, 1).ToHandleChecked();
    value2 = Object::GetElement(isolate, clone, 0).ToHandleChecked();
    CHECK_EQ(*value1, *value2);
    value1 = Object::GetElement(isolate, obj, 0).ToHandleChecked();
    value2 = Object::GetElement(isolate, clone, 1).ToHandleChecked();
    CHECK_EQ(*value1, *value2);
  
    value1 = Object::GetProperty(isolate, obj, second).ToHandleChecked();
    value2 = Object::GetProperty(isolate, clone, first).ToHandleChecked();
    CHECK_EQ(*value1, *value2);
    value1 = Object::GetProperty(isolate, obj, first).ToHandleChecked();
    value2 = Object::GetProperty(isolate, clone, second).ToHandleChecked();
    CHECK_EQ(*value1, *value2);
  }
  
  
  TEST(StringAllocation) {
    CcTest::InitializeVM();
    Isolate* isolate = CcTest::i_isolate();
    Factory* factory = isolate->factory();
  
    const unsigned char chars[] = {0xE5, 0xA4, 0xA7};
    for (int length = 0; length < 100; length++) {
      v8::HandleScope scope(CcTest::isolate());
      char* non_one_byte = NewArray<char>(3 * length + 1);
      char* one_byte = NewArray<char>(length + 1);
      non_one_byte[3 * length] = 0;
      one_byte[length] = 0;
      for (int i = 0; i < length; i++) {
        one_byte[i] = 'a';
        non_one_byte[3 * i] = chars[0];
        non_one_byte[3 * i + 1] = chars[1];
        non_one_byte[3 * i + 2] = chars[2];
      }
      Handle<String> non_one_byte_sym = factory->InternalizeUtf8String(
          Vector<const char>(non_one_byte, 3 * length));
      CHECK_EQ(length, non_one_byte_sym->length());
      Handle<String> one_byte_sym =
          factory->InternalizeString(OneByteVector(one_byte, length));
      CHECK_EQ(length, one_byte_sym->length());
      Handle<String> non_one_byte_str =
          factory->NewStringFromUtf8(Vector<const char>(non_one_byte, 3 * length))
              .ToHandleChecked();
      non_one_byte_str->Hash();
      CHECK_EQ(length, non_one_byte_str->length());
      Handle<String> one_byte_str =
          factory->NewStringFromUtf8(Vector<const char>(one_byte, length))
              .ToHandleChecked();
      one_byte_str->Hash();
      CHECK_EQ(length, one_byte_str->length());
      DeleteArray(non_one_byte);
      DeleteArray(one_byte);
    }
  }
  
  
  static int ObjectsFoundInHeap(Heap* heap, Handle<Object> objs[], int size) {
    // Count the number of objects found in the heap.
    int found_count = 0;
    HeapObjectIterator iterator(heap);
    for (HeapObject obj = iterator.Next(); !obj.is_null();
         obj = iterator.Next()) {
      for (int i = 0; i < size; i++) {
        if (*objs[i] == obj) {
          found_count++;
        }
      }
    }
    return found_count;
  }
  
  
  TEST(Iteration) {
    CcTest::InitializeVM();
    Isolate* isolate = CcTest::i_isolate();
    Factory* factory = isolate->factory();
    v8::HandleScope scope(CcTest::isolate());
  
    // 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_SPACE and NEW_SPACE
    objs[next_objs_index++] = factory->NewJSArray(10);
    objs[next_objs_index++] =
        factory->NewJSArray(10, HOLEY_ELEMENTS, AllocationType::kOld);
  
    // Allocate a small string to OLD_DATA_SPACE and NEW_SPACE
    objs[next_objs_index++] = factory->NewStringFromStaticChars("abcdefghij");
    objs[next_objs_index++] =
        factory->NewStringFromStaticChars("abcdefghij", AllocationType::kOld);
  
    // Allocate a large string (for large object space).
    int large_size = kMaxRegularHeapObjectSize + 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->NewStringFromAsciiChecked(str, AllocationType::kOld);
    delete[] str;
  
    // Add a Map object to look for.
    objs[next_objs_index++] =
        Handle<Map>(HeapObject::cast(*objs[0]).map(), isolate);
  
    CHECK_EQ(objs_count, next_objs_index);
    CHECK_EQ(objs_count, ObjectsFoundInHeap(CcTest::heap(), objs, objs_count));
  }
  
  TEST(TestBytecodeFlushing) {
  #ifndef V8_LITE_MODE
    FLAG_opt = false;
    FLAG_always_opt = false;
    i::FLAG_optimize_for_size = false;
  #endif  // V8_LITE_MODE
    i::FLAG_flush_bytecode = true;
    i::FLAG_allow_natives_syntax = true;
  
    CcTest::InitializeVM();
    v8::Isolate* isolate = CcTest::isolate();
    Isolate* i_isolate = CcTest::i_isolate();
    Factory* factory = i_isolate->factory();
  
    {
      v8::HandleScope scope(isolate);
      v8::Context::New(isolate)->Enter();
      const char* source =
          "function foo() {"
          "  var x = 42;"
          "  var y = 42;"
          "  var z = x + y;"
          "};"
          "foo()";
      Handle<String> foo_name = factory->InternalizeUtf8String("foo");
  
      // This compile will add the code to the compilation cache.
      {
        v8::HandleScope scope(isolate);
        CompileRun(source);
      }
  
      // Check function is compiled.
      Handle<Object> func_value =
          Object::GetProperty(i_isolate, i_isolate->global_object(), foo_name)
              .ToHandleChecked();
      CHECK(func_value->IsJSFunction());
      Handle<JSFunction> function = Handle<JSFunction>::cast(func_value);
      CHECK(function->shared().is_compiled());
  
      // The code will survive at least two GCs.
      CcTest::CollectAllGarbage();
      CcTest::CollectAllGarbage();
      CHECK(function->shared().is_compiled());
  
      // Simulate several GCs that use full marking.
      const int kAgingThreshold = 6;
      for (int i = 0; i < kAgingThreshold; i++) {
        CcTest::CollectAllGarbage();
      }
  
      // foo should no longer be in the compilation cache
      CHECK(!function->shared().is_compiled());
      CHECK(!function->is_compiled());
      // Call foo to get it recompiled.
      CompileRun("foo()");
      CHECK(function->shared().is_compiled());
      CHECK(function->is_compiled());
    }
  }
  
  #ifndef V8_LITE_MODE
  
  TEST(TestOptimizeAfterBytecodeFlushingCandidate) {
    FLAG_opt = true;
    FLAG_always_opt = false;
    i::FLAG_optimize_for_size = false;
    i::FLAG_incremental_marking = true;
    i::FLAG_flush_bytecode = true;
    i::FLAG_allow_natives_syntax = true;
  
    CcTest::InitializeVM();
    Isolate* isolate = CcTest::i_isolate();
    Factory* factory = isolate->factory();
    v8::HandleScope scope(CcTest::isolate());
    const char* source =
        "function foo() {"
        "  var x = 42;"
        "  var y = 42;"
        "  var z = x + y;"
        "};"
        "foo()";
    Handle<String> foo_name = factory->InternalizeUtf8String("foo");
  
    // This compile will add the code to the compilation cache.
    {
      v8::HandleScope scope(CcTest::isolate());
      CompileRun(source);
    }
  
    // Check function is compiled.
    Handle<Object> func_value =
        Object::GetProperty(isolate, isolate->global_object(), foo_name)
            .ToHandleChecked();
    CHECK(func_value->IsJSFunction());
    Handle<JSFunction> function = Handle<JSFunction>::cast(func_value);
    CHECK(function->shared().is_compiled());
  
    // The code will survive at least two GCs.
    CcTest::CollectAllGarbage();
    CcTest::CollectAllGarbage();
    CHECK(function->shared().is_compiled());
  
    // Simulate several GCs that use incremental marking.
    const int kAgingThreshold = 6;
    for (int i = 0; i < kAgingThreshold; i++) {
      heap::SimulateIncrementalMarking(CcTest::heap());
      CcTest::CollectAllGarbage();
    }
    CHECK(!function->shared().is_compiled());
    CHECK(!function->is_compiled());
  
    // This compile will compile the function again.
    {
      v8::HandleScope scope(CcTest::isolate());
      CompileRun("foo();");
    }
  
    // Simulate several GCs that use incremental marking but make sure
    // the loop breaks once the function is enqueued as a candidate.
    for (int i = 0; i < kAgingThreshold; i++) {
      heap::SimulateIncrementalMarking(CcTest::heap());
      if (function->shared().GetBytecodeArray().IsOld()) break;
      CcTest::CollectAllGarbage();
    }
  
    // Force optimization while incremental marking is active and while
    // the function is enqueued as a candidate.
    {
      v8::HandleScope scope(CcTest::isolate());
      CompileRun(
          "%PrepareFunctionForOptimization(foo);"
          "%OptimizeFunctionOnNextCall(foo); foo();");
    }
  
    // Simulate one final GC and make sure the candidate wasn't flushed.
    CcTest::CollectAllGarbage();
    CHECK(function->shared().is_compiled());
    CHECK(function->is_compiled());
  }
  
  #endif  // V8_LITE_MODE
  
  TEST(TestUseOfIncrementalBarrierOnCompileLazy) {
    if (!FLAG_incremental_marking) return;
    // Turn off always_opt because it interferes with running the built-in for
    // the last call to g().
    FLAG_always_opt = false;
    FLAG_allow_natives_syntax = true;
    CcTest::InitializeVM();
    Isolate* isolate = CcTest::i_isolate();
    Factory* factory = isolate->factory();
    Heap* heap = isolate->heap();
    v8::HandleScope scope(CcTest::isolate());
  
    CompileRun(
        "function make_closure(x) {"
        "  return function() { return x + 3 };"
        "}"
        "var f = make_closure(5);"
        "%PrepareFunctionForOptimization(f); f();"
        "var g = make_closure(5);");
  
    // Check f is compiled.
    Handle<String> f_name = factory->InternalizeUtf8String("f");
    Handle<Object> f_value =
        Object::GetProperty(isolate, isolate->global_object(), f_name)
            .ToHandleChecked();
    Handle<JSFunction> f_function = Handle<JSFunction>::cast(f_value);
    CHECK(f_function->is_compiled());
  
    // Check g is not compiled.
    Handle<String> g_name = factory->InternalizeUtf8String("g");
    Handle<Object> g_value =
        Object::GetProperty(isolate, isolate->global_object(), g_name)
            .ToHandleChecked();
    Handle<JSFunction> g_function = Handle<JSFunction>::cast(g_value);
    CHECK(!g_function->is_compiled());
  
    heap::SimulateIncrementalMarking(heap);
    CompileRun("%OptimizeFunctionOnNextCall(f); f();");
  
    // g should now have available an optimized function, unmarked by gc. The
    // CompileLazy built-in will discover it and install it in the closure, and
    // the incremental write barrier should be used.
    CompileRun("g();");
    CHECK(g_function->is_compiled());
  }
  
  TEST(CompilationCacheCachingBehavior) {
    // If we do not have the compilation cache turned off, this test is invalid.
    if (!FLAG_compilation_cache) {
      return;
    }
    CcTest::InitializeVM();
    Isolate* isolate = CcTest::i_isolate();
    Factory* factory = isolate->factory();
    CompilationCache* compilation_cache = isolate->compilation_cache();
    LanguageMode language_mode = construct_language_mode(FLAG_use_strict);
  
    v8::HandleScope scope(CcTest::isolate());
    const char* raw_source =
        "function foo() {"
        "  var x = 42;"
        "  var y = 42;"
        "  var z = x + y;"
        "};"
        "foo();";
    Handle<String> source = factory->InternalizeUtf8String(raw_source);
    Handle<Context> native_context = isolate->native_context();
  
    {
      v8::HandleScope scope(CcTest::isolate());
      CompileRun(raw_source);
    }
  
    // The script should be in the cache now.
    {
      v8::HandleScope scope(CcTest::isolate());
      MaybeHandle<SharedFunctionInfo> cached_script =
          compilation_cache->LookupScript(source, Handle<Object>(), 0, 0,
                                          v8::ScriptOriginOptions(true, false),
                                          native_context, language_mode);
      CHECK(!cached_script.is_null());
    }
  
    // Check that the code cache entry survives at least one GC.
    {
      CcTest::CollectAllGarbage();
      v8::HandleScope scope(CcTest::isolate());
      MaybeHandle<SharedFunctionInfo> cached_script =
          compilation_cache->LookupScript(source, Handle<Object>(), 0, 0,
                                          v8::ScriptOriginOptions(true, false),
                                          native_context, language_mode);
      CHECK(!cached_script.is_null());
  
      // Progress code age until it's old and ready for GC.
      Handle<SharedFunctionInfo> shared = cached_script.ToHandleChecked();
      CHECK(shared->HasBytecodeArray());
      const int kAgingThreshold = 6;
      for (int i = 0; i < kAgingThreshold; i++) {
        shared->GetBytecodeArray().MakeOlder();
      }
    }
  
    CcTest::CollectAllGarbage();
  
    {
      v8::HandleScope scope(CcTest::isolate());
      // Ensure code aging cleared the entry from the cache.
      MaybeHandle<SharedFunctionInfo> cached_script =
          compilation_cache->LookupScript(source, Handle<Object>(), 0, 0,
                                          v8::ScriptOriginOptions(true, false),
                                          native_context, language_mode);
      CHECK(cached_script.is_null());
    }
  }
  
  
  static void OptimizeEmptyFunction(const char* name) {
    HandleScope scope(CcTest::i_isolate());
    EmbeddedVector<char, 256> source;
    SNPrintF(source,
             "function %s() { return 0; }"
             "%%PrepareFunctionForOptimization(%s);"
             "%s(); %s();"
             "%%OptimizeFunctionOnNextCall(%s);"
             "%s();",
             name, name, name, name, name, name);
    CompileRun(source.begin());
  }
  
  
  // Count the number of native contexts in the weak list of native contexts.
  int CountNativeContexts() {
    int count = 0;
    Object object = CcTest::heap()->native_contexts_list();
    while (!object.IsUndefined(CcTest::i_isolate())) {
      count++;
      object = Context::cast(object).next_context_link();
    }
    return count;
  }
  
  TEST(TestInternalWeakLists) {
    FLAG_always_opt = false;
    FLAG_allow_natives_syntax = true;
    v8::V8::Initialize();
  
    // Some flags turn Scavenge collections into Mark-sweep collections
    // and hence are incompatible with this test case.
    if (FLAG_gc_global || FLAG_stress_compaction ||
        FLAG_stress_incremental_marking)
      return;
    FLAG_retain_maps_for_n_gc = 0;
  
    static const int kNumTestContexts = 10;
  
    Isolate* isolate = CcTest::i_isolate();
    HandleScope scope(isolate);
    v8::Local<v8::Context> ctx[kNumTestContexts];
    if (!isolate->use_optimizer()) return;
  
    CHECK_EQ(0, CountNativeContexts());
  
    // Create a number of global contests which gets linked together.
    for (int i = 0; i < kNumTestContexts; i++) {
      ctx[i] = v8::Context::New(CcTest::isolate());
  
      // Collect garbage that might have been created by one of the
      // installed extensions.
      isolate->compilation_cache()->Clear();
      CcTest::CollectAllGarbage();
  
      CHECK_EQ(i + 1, CountNativeContexts());
  
      ctx[i]->Enter();
  
      // Create a handle scope so no function objects get stuck in the outer
      // handle scope.
      HandleScope scope(isolate);
      OptimizeEmptyFunction("f1");
      OptimizeEmptyFunction("f2");
      OptimizeEmptyFunction("f3");
      OptimizeEmptyFunction("f4");
      OptimizeEmptyFunction("f5");
  
      // Remove function f1, and
      CompileRun("f1=null");
  
      // Scavenge treats these references as strong.
      for (int j = 0; j < 10; j++) {
        CcTest::CollectGarbage(NEW_SPACE);
      }
  
      // Mark compact handles the weak references.
      isolate->compilation_cache()->Clear();
      CcTest::CollectAllGarbage();
  
      // Get rid of f3 and f5 in the same way.
      CompileRun("f3=null");
      for (int j = 0; j < 10; j++) {
        CcTest::CollectGarbage(NEW_SPACE);
      }
      CcTest::CollectAllGarbage();
      CompileRun("f5=null");
      for (int j = 0; j < 10; j++) {
        CcTest::CollectGarbage(NEW_SPACE);
      }
      CcTest::CollectAllGarbage();
  
      ctx[i]->Exit();
    }
  
    // Force compilation cache cleanup.
    CcTest::heap()->NotifyContextDisposed(true);
    CcTest::CollectAllGarbage();
  
    // Dispose the native contexts one by one.
    for (int i = 0; i < kNumTestContexts; i++) {
      // TODO(dcarney): is there a better way to do this?
      i::Address* unsafe = reinterpret_cast<i::Address*>(*ctx[i]);
      *unsafe = ReadOnlyRoots(CcTest::heap()).undefined_value().ptr();
      ctx[i].Clear();
  
      // Scavenge treats these references as strong.
      for (int j = 0; j < 10; j++) {
        CcTest::CollectGarbage(i::NEW_SPACE);
        CHECK_EQ(kNumTestContexts - i, CountNativeContexts());
      }
  
      // Mark compact handles the weak references.
      CcTest::CollectAllGarbage();
      CHECK_EQ(kNumTestContexts - i - 1, CountNativeContexts());
    }
  
    CHECK_EQ(0, CountNativeContexts());
  }
  
  
  TEST(TestSizeOfRegExpCode) {
    if (!FLAG_regexp_optimization) return;
  
    v8::V8::Initialize();
  
    Isolate* isolate = CcTest::i_isolate();
    HandleScope scope(isolate);
  
    LocalContext context;
  
    // Adjust source below and this check to match
    // RegExp::kRegExpTooLargeToOptimize.
    CHECK_EQ(i::RegExp::kRegExpTooLargeToOptimize, 20 * KB);
  
    // Compile a regexp that is much larger if we are using regexp optimizations.
    CompileRun(
        "var reg_exp_source = '(?:a|bc|def|ghij|klmno|pqrstu)';"
        "var half_size_reg_exp;"
        "while (reg_exp_source.length < 20 * 1024) {"
        "  half_size_reg_exp = reg_exp_source;"
        "  reg_exp_source = reg_exp_source + reg_exp_source;"
        "}"
        // Flatten string.
        "reg_exp_source.match(/f/);");
  
    // Get initial heap size after several full GCs, which will stabilize
    // the heap size and return with sweeping finished completely.
    CcTest::CollectAllAvailableGarbage();
    MarkCompactCollector* collector = CcTest::heap()->mark_compact_collector();
    if (collector->sweeping_in_progress()) {
      collector->EnsureSweepingCompleted();
    }
    int initial_size = static_cast<int>(CcTest::heap()->SizeOfObjects());
  
    CompileRun("'foo'.match(reg_exp_source);");
    CcTest::CollectAllAvailableGarbage();
    int size_with_regexp = static_cast<int>(CcTest::heap()->SizeOfObjects());
  
    CompileRun("'foo'.match(half_size_reg_exp);");
    CcTest::CollectAllAvailableGarbage();
    int size_with_optimized_regexp =
        static_cast<int>(CcTest::heap()->SizeOfObjects());
  
    int size_of_regexp_code = size_with_regexp - initial_size;
  
    // On some platforms the debug-code flag causes huge amounts of regexp code
    // to be emitted, breaking this test.
    if (!FLAG_debug_code) {
      CHECK_LE(size_of_regexp_code, 1 * MB);
    }
  
    // Small regexp is half the size, but compiles to more than twice the code
    // due to the optimization steps.
    CHECK_GE(size_with_optimized_regexp,
             size_with_regexp + size_of_regexp_code * 2);
  }
  
  
  HEAP_TEST(TestSizeOfObjects) {
    v8::V8::Initialize();
    Isolate* isolate = CcTest::i_isolate();
    Heap* heap = CcTest::heap();
    MarkCompactCollector* collector = heap->mark_compact_collector();
  
    // Get initial heap size after several full GCs, which will stabilize
    // the heap size and return with sweeping finished completely.
    CcTest::CollectAllAvailableGarbage();
    if (collector->sweeping_in_progress()) {
      collector->EnsureSweepingCompleted();
    }
    int initial_size = static_cast<int>(heap->SizeOfObjects());
  
    {
      HandleScope scope(isolate);
      // Allocate objects on several different old-space pages so that
      // concurrent sweeper threads will be busy sweeping the old space on
      // subsequent GC runs.
      AlwaysAllocateScope always_allocate(CcTest::i_isolate());
      int filler_size = static_cast<int>(FixedArray::SizeFor(8192));
      for (int i = 1; i <= 100; i++) {
        isolate->factory()->NewFixedArray(8192, AllocationType::kOld);
        CHECK_EQ(initial_size + i * filler_size,
                 static_cast<int>(heap->SizeOfObjects()));
      }
    }
  
    // The heap size should go back to initial size after a full GC, even
    // though sweeping didn't finish yet.
    CcTest::CollectAllGarbage();
    // Normally sweeping would not be complete here, but no guarantees.
    CHECK_EQ(initial_size, static_cast<int>(heap->SizeOfObjects()));
    // Waiting for sweeper threads should not change heap size.
    if (collector->sweeping_in_progress()) {
      collector->EnsureSweepingCompleted();
    }
    CHECK_EQ(initial_size, static_cast<int>(heap->SizeOfObjects()));
  }
  
  
  TEST(TestAlignmentCalculations) {
    // Maximum fill amounts are consistent.
    int maximum_double_misalignment = kDoubleSize - kTaggedSize;
    int max_word_fill = Heap::GetMaximumFillToAlign(kWordAligned);
    CHECK_EQ(0, max_word_fill);
    int max_double_fill = Heap::GetMaximumFillToAlign(kDoubleAligned);
    CHECK_EQ(maximum_double_misalignment, max_double_fill);
    int max_double_unaligned_fill = Heap::GetMaximumFillToAlign(kDoubleUnaligned);
    CHECK_EQ(maximum_double_misalignment, max_double_unaligned_fill);
  
    Address base = kNullAddress;
    int fill = 0;
  
    // Word alignment never requires fill.
    fill = Heap::GetFillToAlign(base, kWordAligned);
    CHECK_EQ(0, fill);
    fill = Heap::GetFillToAlign(base + kTaggedSize, kWordAligned);
    CHECK_EQ(0, fill);
  
    // No fill is required when address is double aligned.
    fill = Heap::GetFillToAlign(base, kDoubleAligned);
    CHECK_EQ(0, fill);
    // Fill is required if address is not double aligned.
    fill = Heap::GetFillToAlign(base + kTaggedSize, kDoubleAligned);
    CHECK_EQ(maximum_double_misalignment, fill);
    // kDoubleUnaligned has the opposite fill amounts.
    fill = Heap::GetFillToAlign(base, kDoubleUnaligned);
    CHECK_EQ(maximum_double_misalignment, fill);
    fill = Heap::GetFillToAlign(base + kTaggedSize, kDoubleUnaligned);
    CHECK_EQ(0, fill);
  }
  
  static HeapObject NewSpaceAllocateAligned(int size,
                                            AllocationAlignment alignment) {
    Heap* heap = CcTest::heap();
    AllocationResult allocation =
        heap->new_space()->AllocateRawAligned(size, alignment);
    HeapObject obj;
    allocation.To(&obj);
    heap->CreateFillerObjectAt(obj.address(), size, ClearRecordedSlots::kNo);
    return obj;
  }
  
  // Get new space allocation into the desired alignment.
  static Address AlignNewSpace(AllocationAlignment alignment, int offset) {
    Address* top_addr = CcTest::heap()->new_space()->allocation_top_address();
    int fill = Heap::GetFillToAlign(*top_addr, alignment);
    int allocation = fill + offset;
    if (allocation) {
      NewSpaceAllocateAligned(allocation, kWordAligned);
    }
    return *top_addr;
  }
  
  
  TEST(TestAlignedAllocation) {
    // Double misalignment is 4 on 32-bit platforms or when pointer compression
    // is enabled, 0 on 64-bit ones when pointer compression is disabled.
    const intptr_t double_misalignment = kDoubleSize - kTaggedSize;
    Address* top_addr = CcTest::heap()->new_space()->allocation_top_address();
    Address start;
    HeapObject obj;
    HeapObject filler;
    if (double_misalignment) {
      // Allocate a pointer sized object that must be double aligned at an
      // aligned address.
      start = AlignNewSpace(kDoubleAligned, 0);
      obj = NewSpaceAllocateAligned(kTaggedSize, kDoubleAligned);
      CHECK(IsAligned(obj.address(), kDoubleAlignment));
      // There is no filler.
      CHECK_EQ(kTaggedSize, *top_addr - start);
  
      // Allocate a second pointer sized object that must be double aligned at an
      // unaligned address.
      start = AlignNewSpace(kDoubleAligned, kTaggedSize);
      obj = NewSpaceAllocateAligned(kTaggedSize, kDoubleAligned);
      CHECK(IsAligned(obj.address(), kDoubleAlignment));
      // There is a filler object before the object.
      filler = HeapObject::FromAddress(start);
      CHECK(obj != filler && filler.IsFiller() && filler.Size() == kTaggedSize);
      CHECK_EQ(kTaggedSize + double_misalignment, *top_addr - start);
  
      // Similarly for kDoubleUnaligned.
      start = AlignNewSpace(kDoubleUnaligned, 0);
      obj = NewSpaceAllocateAligned(kTaggedSize, kDoubleUnaligned);
      CHECK(IsAligned(obj.address() + kTaggedSize, kDoubleAlignment));
      CHECK_EQ(kTaggedSize, *top_addr - start);
      start = AlignNewSpace(kDoubleUnaligned, kTaggedSize);
      obj = NewSpaceAllocateAligned(kTaggedSize, kDoubleUnaligned);
      CHECK(IsAligned(obj.address() + kTaggedSize, kDoubleAlignment));
      // There is a filler object before the object.
      filler = HeapObject::FromAddress(start);
      CHECK(obj != filler && filler.IsFiller() && filler.Size() == kTaggedSize);
      CHECK_EQ(kTaggedSize + double_misalignment, *top_addr - start);
    }
  }
  
  static HeapObject OldSpaceAllocateAligned(int size,
                                            AllocationAlignment alignment) {
    Heap* heap = CcTest::heap();
    AllocationResult allocation =
        heap->old_space()->AllocateRawAligned(size, alignment);
    HeapObject obj;
    allocation.To(&obj);
    heap->CreateFillerObjectAt(obj.address(), size, ClearRecordedSlots::kNo);
    return obj;
  }
  
  // Get old space allocation into the desired alignment.
  static Address AlignOldSpace(AllocationAlignment alignment, int offset) {
    Address* top_addr = CcTest::heap()->old_space()->allocation_top_address();
    int fill = Heap::GetFillToAlign(*top_addr, alignment);
    int allocation = fill + offset;
    if (allocation) {
      OldSpaceAllocateAligned(allocation, kWordAligned);
    }
    Address top = *top_addr;
    // Now force the remaining allocation onto the free list.
    CcTest::heap()->old_space()->FreeLinearAllocationArea();
    return top;
  }
  
  
  // Test the case where allocation must be done from the free list, so filler
  // may precede or follow the object.
  TEST(TestAlignedOverAllocation) {
    Heap* heap = CcTest::heap();
    // Test checks for fillers before and behind objects and requires a fresh
    // page and empty free list.
    heap::AbandonCurrentlyFreeMemory(heap->old_space());
    // Allocate a dummy object to properly set up the linear allocation info.
    AllocationResult dummy = heap->old_space()->AllocateRawUnaligned(kTaggedSize);
    CHECK(!dummy.IsRetry());
    heap->CreateFillerObjectAt(dummy.ToObjectChecked().address(), kTaggedSize,
                               ClearRecordedSlots::kNo);
  
    // Double misalignment is 4 on 32-bit platforms or when pointer compression
    // is enabled, 0 on 64-bit ones when pointer compression is disabled.
    const intptr_t double_misalignment = kDoubleSize - kTaggedSize;
    Address start;
    HeapObject obj;
    HeapObject filler;
    if (double_misalignment) {
      start = AlignOldSpace(kDoubleAligned, 0);
      obj = OldSpaceAllocateAligned(kTaggedSize, kDoubleAligned);
      // The object is aligned.
      CHECK(IsAligned(obj.address(), kDoubleAlignment));
      // Try the opposite alignment case.
      start = AlignOldSpace(kDoubleAligned, kTaggedSize);
      obj = OldSpaceAllocateAligned(kTaggedSize, kDoubleAligned);
      CHECK(IsAligned(obj.address(), kDoubleAlignment));
      filler = HeapObject::FromAddress(start);
      CHECK(obj != filler);
      CHECK(filler.IsFiller());
      CHECK_EQ(kTaggedSize, filler.Size());
      CHECK(obj != filler && filler.IsFiller() && filler.Size() == kTaggedSize);
  
      // Similarly for kDoubleUnaligned.
      start = AlignOldSpace(kDoubleUnaligned, 0);
      obj = OldSpaceAllocateAligned(kTaggedSize, kDoubleUnaligned);
      // The object is aligned.
      CHECK(IsAligned(obj.address() + kTaggedSize, kDoubleAlignment));
      // Try the opposite alignment case.
      start = AlignOldSpace(kDoubleUnaligned, kTaggedSize);
      obj = OldSpaceAllocateAligned(kTaggedSize, kDoubleUnaligned);
      CHECK(IsAligned(obj.address() + kTaggedSize, kDoubleAlignment));
      filler = HeapObject::FromAddress(start);
      CHECK(obj != filler && filler.IsFiller() && filler.Size() == kTaggedSize);
    }
  }
  
  TEST(HeapNumberAlignment) {
    CcTest::InitializeVM();
    Isolate* isolate = CcTest::i_isolate();
    Factory* factory = isolate->factory();
    Heap* heap = isolate->heap();
    HandleScope sc(isolate);
  
    const auto required_alignment =
        HeapObject::RequiredAlignment(*factory->heap_number_map());
    const int maximum_misalignment =
        Heap::GetMaximumFillToAlign(required_alignment);
  
    for (int offset = 0; offset <= maximum_misalignment; offset += kTaggedSize) {
      AlignNewSpace(required_alignment, offset);
      Handle<Object> number_new = factory->NewNumber(1.000123);
      CHECK(number_new->IsHeapNumber());
      CHECK(Heap::InYoungGeneration(*number_new));
      CHECK_EQ(0, Heap::GetFillToAlign(HeapObject::cast(*number_new).address(),
                                       required_alignment));
  
      AlignOldSpace(required_alignment, offset);
      Handle<Object> number_old =
          factory->NewNumber(1.000321, AllocationType::kOld);
      CHECK(number_old->IsHeapNumber());
      CHECK(heap->InOldSpace(*number_old));
      CHECK_EQ(0, Heap::GetFillToAlign(HeapObject::cast(*number_old).address(),
                                       required_alignment));
    }
  }
  
  TEST(MutableHeapNumberAlignment) {
    CcTest::InitializeVM();
    Isolate* isolate = CcTest::i_isolate();
    Factory* factory = isolate->factory();
    Heap* heap = isolate->heap();
    HandleScope sc(isolate);
  
    const auto required_alignment =
        HeapObject::RequiredAlignment(*factory->mutable_heap_number_map());
    const int maximum_misalignment =
        Heap::GetMaximumFillToAlign(required_alignment);
  
    for (int offset = 0; offset <= maximum_misalignment; offset += kTaggedSize) {
      AlignNewSpace(required_alignment, offset);
      Handle<Object> number_new = factory->NewMutableHeapNumber(1.000123);
      CHECK(number_new->IsMutableHeapNumber());
      CHECK(Heap::InYoungGeneration(*number_new));
      CHECK_EQ(0, Heap::GetFillToAlign(HeapObject::cast(*number_new).address(),
                                       required_alignment));
  
      AlignOldSpace(required_alignment, offset);
      Handle<Object> number_old =
          factory->NewMutableHeapNumber(1.000321, AllocationType::kOld);
      CHECK(number_old->IsMutableHeapNumber());
      CHECK(heap->InOldSpace(*number_old));
      CHECK_EQ(0, Heap::GetFillToAlign(HeapObject::cast(*number_old).address(),
                                       required_alignment));
    }
  }
  
  TEST(TestSizeOfObjectsVsHeapObjectIteratorPrecision) {
    CcTest::InitializeVM();
    HeapObjectIterator iterator(CcTest::heap());
    intptr_t size_of_objects_1 = CcTest::heap()->SizeOfObjects();
    intptr_t size_of_objects_2 = 0;
    for (HeapObject obj = iterator.Next(); !obj.is_null();
         obj = iterator.Next()) {
      if (!obj.IsFreeSpace()) {
        size_of_objects_2 += obj.Size();
      }
    }
    // Delta must be within 5% of the larger result.
    // TODO(gc): Tighten this up by distinguishing between byte
    // arrays that are real and those that merely mark free space
    // on the heap.
    if (size_of_objects_1 > size_of_objects_2) {
      intptr_t delta = size_of_objects_1 - size_of_objects_2;
      PrintF("Heap::SizeOfObjects: %" V8PRIdPTR
             ", "
             "Iterator: %" V8PRIdPTR
             ", "
             "delta: %" V8PRIdPTR "\n",
             size_of_objects_1, size_of_objects_2, delta);
      CHECK_GT(size_of_objects_1 / 20, delta);
    } else {
      intptr_t delta = size_of_objects_2 - size_of_objects_1;
      PrintF("Heap::SizeOfObjects: %" V8PRIdPTR
             ", "
             "Iterator: %" V8PRIdPTR
             ", "
             "delta: %" V8PRIdPTR "\n",
             size_of_objects_1, size_of_objects_2, delta);
      CHECK_GT(size_of_objects_2 / 20, delta);
    }
  }
  
  TEST(GrowAndShrinkNewSpace) {
    // Avoid shrinking new space in GC epilogue. This can happen if allocation
    // throughput samples have been taken while executing the benchmark.
    FLAG_predictable = true;
  
    CcTest::InitializeVM();
    Heap* heap = CcTest::heap();
    NewSpace* new_space = heap->new_space();
  
    if (heap->MaxSemiSpaceSize() == heap->InitialSemiSpaceSize()) {
      return;
    }
  
    // Make sure we're in a consistent state to start out.
    CcTest::CollectAllGarbage();
    CcTest::CollectAllGarbage();
    new_space->Shrink();
  
    // Explicitly growing should double the space capacity.
    size_t old_capacity, new_capacity;
    old_capacity = new_space->TotalCapacity();
    new_space->Grow();
    new_capacity = new_space->TotalCapacity();
    CHECK_EQ(2 * old_capacity, new_capacity);
  
    old_capacity = new_space->TotalCapacity();
    {
      v8::HandleScope temporary_scope(CcTest::isolate());
      heap::SimulateFullSpace(new_space);
    }
    new_capacity = new_space->TotalCapacity();
    CHECK_EQ(old_capacity, new_capacity);
  
    // Explicitly shrinking should not affect space capacity.
    old_capacity = new_space->TotalCapacity();
    new_space->Shrink();
    new_capacity = new_space->TotalCapacity();
    CHECK_EQ(old_capacity, new_capacity);
  
    // Let the scavenger empty the new space.
    CcTest::CollectGarbage(NEW_SPACE);
    CHECK_LE(new_space->Size(), old_capacity);
  
    // Explicitly shrinking should halve the space capacity.
    old_capacity = new_space->TotalCapacity();
    new_space->Shrink();
    new_capacity = new_space->TotalCapacity();
    CHECK_EQ(old_capacity, 2 * new_capacity);
  
    // Consecutive shrinking should not affect space capacity.
    old_capacity = new_space->TotalCapacity();
    new_space->Shrink();
    new_space->Shrink();
    new_space->Shrink();
    new_capacity = new_space->TotalCapacity();
    CHECK_EQ(old_capacity, new_capacity);
  }
  
  TEST(CollectingAllAvailableGarbageShrinksNewSpace) {
    CcTest::InitializeVM();
    Heap* heap = CcTest::heap();
    if (heap->MaxSemiSpaceSize() == heap->InitialSemiSpaceSize()) {
      return;
    }
  
    v8::HandleScope scope(CcTest::isolate());
    NewSpace* new_space = heap->new_space();
    size_t old_capacity, new_capacity;
    old_capacity = new_space->TotalCapacity();
    new_space->Grow();
    new_capacity = new_space->TotalCapacity();
    CHECK_EQ(2 * old_capacity, new_capacity);
    {
      v8::HandleScope temporary_scope(CcTest::isolate());
      heap::SimulateFullSpace(new_space);
    }
    CcTest::CollectAllAvailableGarbage();
    new_capacity = new_space->TotalCapacity();
    CHECK_EQ(old_capacity, new_capacity);
  }
  
  static int NumberOfGlobalObjects() {
    int count = 0;
    HeapObjectIterator iterator(CcTest::heap());
    for (HeapObject obj = iterator.Next(); !obj.is_null();
         obj = iterator.Next()) {
      if (obj.IsJSGlobalObject()) count++;
    }
    return count;
  }
  
  
  // Test that we don't embed maps from foreign contexts into
  // optimized code.
  TEST(LeakNativeContextViaMap) {
    FLAG_allow_natives_syntax = true;
    v8::Isolate* isolate = CcTest::isolate();
    v8::HandleScope outer_scope(isolate);
    v8::Persistent<v8::Context> ctx1p;
    v8::Persistent<v8::Context> ctx2p;
    {
      v8::HandleScope scope(isolate);
      ctx1p.Reset(isolate, v8::Context::New(isolate));
      ctx2p.Reset(isolate, v8::Context::New(isolate));
      v8::Local<v8::Context>::New(isolate, ctx1p)->Enter();
    }
  
    CcTest::CollectAllAvailableGarbage();
    CHECK_EQ(2, NumberOfGlobalObjects());
  
    {
      v8::HandleScope inner_scope(isolate);
      CompileRun("var v = {x: 42}");
      v8::Local<v8::Context> ctx1 = v8::Local<v8::Context>::New(isolate, ctx1p);
      v8::Local<v8::Context> ctx2 = v8::Local<v8::Context>::New(isolate, ctx2p);
      v8::Local<v8::Value> v =
          ctx1->Global()->Get(ctx1, v8_str("v")).ToLocalChecked();
      ctx2->Enter();
      CHECK(ctx2->Global()->Set(ctx2, v8_str("o"), v).FromJust());
      v8::Local<v8::Value> res = CompileRun(
          "function f() { return o.x; }"
          "%PrepareFunctionForOptimization(f);"
          "for (var i = 0; i < 10; ++i) f();"
          "%OptimizeFunctionOnNextCall(f);"
          "f();");
      CHECK_EQ(42, res->Int32Value(ctx2).FromJust());
      CHECK(ctx2->Global()
                ->Set(ctx2, v8_str("o"), v8::Int32::New(isolate, 0))
                .FromJust());
      ctx2->Exit();
      v8::Local<v8::Context>::New(isolate, ctx1)->Exit();
      ctx1p.Reset();
      isolate->ContextDisposedNotification();
    }
    CcTest::CollectAllAvailableGarbage();
    CHECK_EQ(1, NumberOfGlobalObjects());
    ctx2p.Reset();
    CcTest::CollectAllAvailableGarbage();
    CHECK_EQ(0, NumberOfGlobalObjects());
  }
  
  
  // Test that we don't embed functions from foreign contexts into
  // optimized code.
  TEST(LeakNativeContextViaFunction) {
    FLAG_allow_natives_syntax = true;
    v8::Isolate* isolate = CcTest::isolate();
    v8::HandleScope outer_scope(isolate);
    v8::Persistent<v8::Context> ctx1p;
    v8::Persistent<v8::Context> ctx2p;
    {
      v8::HandleScope scope(isolate);
      ctx1p.Reset(isolate, v8::Context::New(isolate));
      ctx2p.Reset(isolate, v8::Context::New(isolate));
      v8::Local<v8::Context>::New(isolate, ctx1p)->Enter();
    }
  
    CcTest::CollectAllAvailableGarbage();
    CHECK_EQ(2, NumberOfGlobalObjects());
  
    {
      v8::HandleScope inner_scope(isolate);
      CompileRun("var v = function() { return 42; }");
      v8::Local<v8::Context> ctx1 = v8::Local<v8::Context>::New(isolate, ctx1p);
      v8::Local<v8::Context> ctx2 = v8::Local<v8::Context>::New(isolate, ctx2p);
      v8::Local<v8::Value> v =
          ctx1->Global()->Get(ctx1, v8_str("v")).ToLocalChecked();
      ctx2->Enter();
      CHECK(ctx2->Global()->Set(ctx2, v8_str("o"), v).FromJust());
      v8::Local<v8::Value> res = CompileRun(
          "function f(x) { return x(); }"
          "%PrepareFunctionForOptimization(f);"
          "for (var i = 0; i < 10; ++i) f(o);"
          "%OptimizeFunctionOnNextCall(f);"
          "f(o);");
      CHECK_EQ(42, res->Int32Value(ctx2).FromJust());
      CHECK(ctx2->Global()
                ->Set(ctx2, v8_str("o"), v8::Int32::New(isolate, 0))
                .FromJust());
      ctx2->Exit();
      ctx1->Exit();
      ctx1p.Reset();
      isolate->ContextDisposedNotification();
    }
    CcTest::CollectAllAvailableGarbage();
    CHECK_EQ(1, NumberOfGlobalObjects());
    ctx2p.Reset();
    CcTest::CollectAllAvailableGarbage();
    CHECK_EQ(0, NumberOfGlobalObjects());
  }
  
  
  TEST(LeakNativeContextViaMapKeyed) {
    FLAG_allow_natives_syntax = true;
    v8::Isolate* isolate = CcTest::isolate();
    v8::HandleScope outer_scope(isolate);
    v8::Persistent<v8::Context> ctx1p;
    v8::Persistent<v8::Context> ctx2p;
    {
      v8::HandleScope scope(isolate);
      ctx1p.Reset(isolate, v8::Context::New(isolate));
      ctx2p.Reset(isolate, v8::Context::New(isolate));
      v8::Local<v8::Context>::New(isolate, ctx1p)->Enter();
    }
  
    CcTest::CollectAllAvailableGarbage();
    CHECK_EQ(2, NumberOfGlobalObjects());
  
    {
      v8::HandleScope inner_scope(isolate);
      CompileRun("var v = [42, 43]");
      v8::Local<v8::Context> ctx1 = v8::Local<v8::Context>::New(isolate, ctx1p);
      v8::Local<v8::Context> ctx2 = v8::Local<v8::Context>::New(isolate, ctx2p);
      v8::Local<v8::Value> v =
          ctx1->Global()->Get(ctx1, v8_str("v")).ToLocalChecked();
      ctx2->Enter();
      CHECK(ctx2->Global()->Set(ctx2, v8_str("o"), v).FromJust());
      v8::Local<v8::Value> res = CompileRun(
          "function f() { return o[0]; }"
          "%PrepareFunctionForOptimization(f);"
          "for (var i = 0; i < 10; ++i) f();"
          "%OptimizeFunctionOnNextCall(f);"
          "f();");
      CHECK_EQ(42, res->Int32Value(ctx2).FromJust());
      CHECK(ctx2->Global()
                ->Set(ctx2, v8_str("o"), v8::Int32::New(isolate, 0))
                .FromJust());
      ctx2->Exit();
      ctx1->Exit();
      ctx1p.Reset();
      isolate->ContextDisposedNotification();
    }
    CcTest::CollectAllAvailableGarbage();
    CHECK_EQ(1, NumberOfGlobalObjects());
    ctx2p.Reset();
    CcTest::CollectAllAvailableGarbage();
    CHECK_EQ(0, NumberOfGlobalObjects());
  }
  
  
  TEST(LeakNativeContextViaMapProto) {
    FLAG_allow_natives_syntax = true;
    v8::Isolate* isolate = CcTest::isolate();
    v8::HandleScope outer_scope(isolate);
    v8::Persistent<v8::Context> ctx1p;
    v8::Persistent<v8::Context> ctx2p;
    {
      v8::HandleScope scope(isolate);
      ctx1p.Reset(isolate, v8::Context::New(isolate));
      ctx2p.Reset(isolate, v8::Context::New(isolate));
      v8::Local<v8::Context>::New(isolate, ctx1p)->Enter();
    }
  
    CcTest::CollectAllAvailableGarbage();
    CHECK_EQ(2, NumberOfGlobalObjects());
  
    {
      v8::HandleScope inner_scope(isolate);
      CompileRun("var v = { y: 42}");
      v8::Local<v8::Context> ctx1 = v8::Local<v8::Context>::New(isolate, ctx1p);
      v8::Local<v8::Context> ctx2 = v8::Local<v8::Context>::New(isolate, ctx2p);
      v8::Local<v8::Value> v =
          ctx1->Global()->Get(ctx1, v8_str("v")).ToLocalChecked();
      ctx2->Enter();
      CHECK(ctx2->Global()->Set(ctx2, v8_str("o"), v).FromJust());
      v8::Local<v8::Value> res = CompileRun(
          "function f() {"
          "  var p = {x: 42};"
          "  p.__proto__ = o;"
          "  return p.x;"
          "}"
          "%PrepareFunctionForOptimization(f);"
          "for (var i = 0; i < 10; ++i) f();"
          "%OptimizeFunctionOnNextCall(f);"
          "f();");
      CHECK_EQ(42, res->Int32Value(ctx2).FromJust());
      CHECK(ctx2->Global()
                ->Set(ctx2, v8_str("o"), v8::Int32::New(isolate, 0))
                .FromJust());
      ctx2->Exit();
      ctx1->Exit();
      ctx1p.Reset();
      isolate->ContextDisposedNotification();
    }
    CcTest::CollectAllAvailableGarbage();
    CHECK_EQ(1, NumberOfGlobalObjects());
    ctx2p.Reset();
    CcTest::CollectAllAvailableGarbage();
    CHECK_EQ(0, NumberOfGlobalObjects());
  }
  
  
  TEST(InstanceOfStubWriteBarrier) {
    if (!FLAG_incremental_marking) return;
    ManualGCScope manual_gc_scope;
    FLAG_allow_natives_syntax = true;
  #ifdef VERIFY_HEAP
    FLAG_verify_heap = true;
  #endif
  
    CcTest::InitializeVM();
    if (!CcTest::i_isolate()->use_optimizer()) return;
    if (FLAG_force_marking_deque_overflows) return;
    v8::HandleScope outer_scope(CcTest::isolate());
    v8::Local<v8::Context> ctx = CcTest::isolate()->GetCurrentContext();
  
    {
      v8::HandleScope scope(CcTest::isolate());
      CompileRun(
          "function foo () { }"
          "function mkbar () { return new (new Function(\"\")) (); }"
          "function f (x) { return (x instanceof foo); }"
          "function g () { f(mkbar()); }"
          "%PrepareFunctionForOptimization(f);"
          "f(new foo()); f(new foo());"
          "%OptimizeFunctionOnNextCall(f);"
          "f(new foo()); g();");
    }
  
    IncrementalMarking* marking = CcTest::heap()->incremental_marking();
    marking->Stop();
    CcTest::heap()->StartIncrementalMarking(i::Heap::kNoGCFlags,
                                            i::GarbageCollectionReason::kTesting);
  
    i::Handle<JSFunction> f = i::Handle<JSFunction>::cast(
        v8::Utils::OpenHandle(*v8::Local<v8::Function>::Cast(
            CcTest::global()->Get(ctx, v8_str("f")).ToLocalChecked())));
  
    CHECK(f->IsOptimized());
  
    IncrementalMarking::MarkingState* marking_state = marking->marking_state();
  
    const double kStepSizeInMs = 100;
    while (!marking_state->IsBlack(f->code()) && !marking->IsStopped()) {
      // Discard any pending GC requests otherwise we will get GC when we enter
      // code below.
      marking->V8Step(kStepSizeInMs, IncrementalMarking::NO_GC_VIA_STACK_GUARD,
                      StepOrigin::kV8);
    }
  
    CHECK(marking->IsMarking());
  
    {
      v8::HandleScope scope(CcTest::isolate());
      v8::Local<v8::Object> global = CcTest::global();
      v8::Local<v8::Function> g = v8::Local<v8::Function>::Cast(
          global->Get(ctx, v8_str("g")).ToLocalChecked());
      g->Call(ctx, global, 0, nullptr).ToLocalChecked();
    }
  
    CcTest::heap()->incremental_marking()->set_should_hurry(true);
    CcTest::CollectGarbage(OLD_SPACE);
  }
  
  HEAP_TEST(GCFlags) {
    if (!FLAG_incremental_marking) return;
    CcTest::InitializeVM();
    Heap* heap = CcTest::heap();
  
    heap->set_current_gc_flags(Heap::kNoGCFlags);
    CHECK_EQ(Heap::kNoGCFlags, heap->current_gc_flags_);
  
    // Check whether we appropriately reset flags after GC.
    CcTest::heap()->CollectAllGarbage(Heap::kReduceMemoryFootprintMask,
                                      GarbageCollectionReason::kTesting);
    CHECK_EQ(Heap::kNoGCFlags, heap->current_gc_flags_);
  
    MarkCompactCollector* collector = heap->mark_compact_collector();
    if (collector->sweeping_in_progress()) {
      collector->EnsureSweepingCompleted();
    }
  
    IncrementalMarking* marking = heap->incremental_marking();
    marking->Stop();
    heap->StartIncrementalMarking(Heap::kReduceMemoryFootprintMask,
                                  i::GarbageCollectionReason::kTesting);
    CHECK_NE(0, heap->current_gc_flags_ & Heap::kReduceMemoryFootprintMask);
  
    CcTest::CollectGarbage(NEW_SPACE);
    // NewSpace scavenges should not overwrite the flags.
    CHECK_NE(0, heap->current_gc_flags_ & Heap::kReduceMemoryFootprintMask);
  
    CcTest::CollectAllGarbage();
    CHECK_EQ(Heap::kNoGCFlags, heap->current_gc_flags_);
  }
  
  HEAP_TEST(Regress845060) {
    // Regression test for crbug.com/845060, where a raw pointer to a string's
    // data was kept across an allocation. If the allocation causes GC and
    // moves the string, such raw pointers become invalid.
    FLAG_allow_natives_syntax = true;
    FLAG_stress_incremental_marking = false;
    FLAG_stress_compaction = false;
    CcTest::InitializeVM();
    LocalContext context;
    v8::HandleScope scope(CcTest::isolate());
    Heap* heap = CcTest::heap();
  
    // Preparation: create a string in new space.
    Local<Value> str = CompileRun("var str = (new Array(10000)).join('x'); str");
    CHECK(Heap::InYoungGeneration(*v8::Utils::OpenHandle(*str)));
  
    // Idle incremental marking sets the "kReduceMemoryFootprint" flag, which
    // causes from_space to be unmapped after scavenging.
    heap->StartIdleIncrementalMarking(GarbageCollectionReason::kTesting);
    CHECK(heap->ShouldReduceMemory());
  
    // Run the test (which allocates results) until the original string was
    // promoted to old space. Unmapping of from_space causes accesses to any
    // stale raw pointers to crash.
    CompileRun("while (%InYoungGeneration(str)) { str.split(''); }");
    CHECK(!Heap::InYoungGeneration(*v8::Utils::OpenHandle(*str)));
  }
  
  TEST(IdleNotificationFinishMarking) {
    if (!FLAG_incremental_marking) return;
    ManualGCScope manual_gc_scope;
    FLAG_allow_natives_syntax = true;
    CcTest::InitializeVM();
    const int initial_gc_count = CcTest::heap()->gc_count();
    heap::SimulateFullSpace(CcTest::heap()->old_space());
    IncrementalMarking* marking = CcTest::heap()->incremental_marking();
    marking->Stop();
    CcTest::heap()->StartIncrementalMarking(i::Heap::kNoGCFlags,
                                            i::GarbageCollectionReason::kTesting);
  
    CHECK_EQ(CcTest::heap()->gc_count(), initial_gc_count);
  
    const double kStepSizeInMs = 100;
    do {
      marking->V8Step(kStepSizeInMs, IncrementalMarking::NO_GC_VIA_STACK_GUARD,
                      StepOrigin::kV8);
    } while (
        !CcTest::heap()->mark_compact_collector()->marking_worklist()->IsEmpty());
  
    marking->SetWeakClosureWasOverApproximatedForTesting(true);
  
    // The next idle notification has to finish incremental marking.
    const double kLongIdleTime = 1000.0;
    CcTest::isolate()->IdleNotificationDeadline(
        (v8::base::TimeTicks::HighResolutionNow().ToInternalValue() /
         static_cast<double>(v8::base::Time::kMicrosecondsPerSecond)) +
        kLongIdleTime);
    CHECK_EQ(CcTest::heap()->gc_count(), initial_gc_count + 1);
  }
  
  
  // Test that HAllocateObject will always return an object in new-space.
  TEST(OptimizedAllocationAlwaysInNewSpace) {
    FLAG_allow_natives_syntax = true;
    CcTest::InitializeVM();
    if (!CcTest::i_isolate()->use_optimizer() || FLAG_always_opt) return;
    if (FLAG_gc_global || FLAG_stress_compaction ||
        FLAG_stress_incremental_marking)
      return;
    v8::HandleScope scope(CcTest::isolate());
    v8::Local<v8::Context> ctx = CcTest::isolate()->GetCurrentContext();
    heap::SimulateFullSpace(CcTest::heap()->new_space());
    AlwaysAllocateScope always_allocate(CcTest::i_isolate());
    v8::Local<v8::Value> res = CompileRun(
        "function c(x) {"
        "  this.x = x;"
        "  for (var i = 0; i < 32; i++) {"
        "    this['x' + i] = x;"
        "  }"
        "}"
        "function f(x) { return new c(x); };"
        "%PrepareFunctionForOptimization(f);"
        "f(1); f(2); f(3);"
        "%OptimizeFunctionOnNextCall(f);"
        "f(4);");
  
    CHECK_EQ(4, res.As<v8::Object>()
                    ->GetRealNamedProperty(ctx, v8_str("x"))
                    .ToLocalChecked()
                    ->Int32Value(ctx)
                    .FromJust());
  
    i::Handle<JSReceiver> o =
        v8::Utils::OpenHandle(*v8::Local<v8::Object>::Cast(res));
  
    CHECK(Heap::InYoungGeneration(*o));
  }
  
  
  TEST(OptimizedPretenuringAllocationFolding) {
    FLAG_allow_natives_syntax = true;
    FLAG_expose_gc = true;
    CcTest::InitializeVM();
    if (!CcTest::i_isolate()->use_optimizer() || FLAG_always_opt) return;
    if (FLAG_gc_global || FLAG_stress_compaction ||
        FLAG_stress_incremental_marking)
      return;
    v8::HandleScope scope(CcTest::isolate());
    v8::Local<v8::Context> ctx = CcTest::isolate()->GetCurrentContext();
    // Grow new space unitl maximum capacity reached.
    while (!CcTest::heap()->new_space()->IsAtMaximumCapacity()) {
      CcTest::heap()->new_space()->Grow();
    }
  
    i::ScopedVector<char> source(1024);
    i::SNPrintF(source,
                "var number_elements = %d;"
                "var elements = new Array();"
                "function f() {"
                "  for (var i = 0; i < number_elements; i++) {"
                "    elements[i] = [[{}], [1.1]];"
                "  }"
                "  return elements[number_elements-1]"
                "};"
                "%%PrepareFunctionForOptimization(f);"
                "f(); gc();"
                "f(); f();"
                "%%OptimizeFunctionOnNextCall(f);"
                "f();",
                kPretenureCreationCount);
  
    v8::Local<v8::Value> res = CompileRun(source.begin());
  
    v8::Local<v8::Value> int_array =
        v8::Object::Cast(*res)->Get(ctx, v8_str("0")).ToLocalChecked();
    i::Handle<JSObject> int_array_handle = i::Handle<JSObject>::cast(
        v8::Utils::OpenHandle(*v8::Local<v8::Object>::Cast(int_array)));
    v8::Local<v8::Value> double_array =
        v8::Object::Cast(*res)->Get(ctx, v8_str("1")).ToLocalChecked();
    i::Handle<JSObject> double_array_handle = i::Handle<JSObject>::cast(
        v8::Utils::OpenHandle(*v8::Local<v8::Object>::Cast(double_array)));
  
    i::Handle<JSReceiver> o =
        v8::Utils::OpenHandle(*v8::Local<v8::Object>::Cast(res));
    CHECK(CcTest::heap()->InOldSpace(*o));
    CHECK(CcTest::heap()->InOldSpace(*int_array_handle));
    CHECK(CcTest::heap()->InOldSpace(int_array_handle->elements()));
    CHECK(CcTest::heap()->InOldSpace(*double_array_handle));
    CHECK(CcTest::heap()->InOldSpace(double_array_handle->elements()));
  }
  
  
  TEST(OptimizedPretenuringObjectArrayLiterals) {
    FLAG_allow_natives_syntax = true;
    FLAG_expose_gc = true;
    CcTest::InitializeVM();
    if (!CcTest::i_isolate()->use_optimizer() || FLAG_always_opt) return;
    if (FLAG_gc_global || FLAG_stress_compaction ||
        FLAG_stress_incremental_marking) {
      return;
    }
    v8::HandleScope scope(CcTest::isolate());
  
    // Grow new space unitl maximum capacity reached.
    while (!CcTest::heap()->new_space()->IsAtMaximumCapacity()) {
      CcTest::heap()->new_space()->Grow();
    }
  
    i::ScopedVector<char> source(1024);
    i::SNPrintF(source,
                "var number_elements = %d;"
                "var elements = new Array(number_elements);"
                "function f() {"
                "  for (var i = 0; i < number_elements; i++) {"
                "    elements[i] = [{}, {}, {}];"
                "  }"
                "  return elements[number_elements - 1];"
                "};"
                "%%PrepareFunctionForOptimization(f);"
                "f(); gc();"
                "f(); f();"
                "%%OptimizeFunctionOnNextCall(f);"
                "f();",
                kPretenureCreationCount);
  
    v8::Local<v8::Value> res = CompileRun(source.begin());
  
    i::Handle<JSObject> o = Handle<JSObject>::cast(
        v8::Utils::OpenHandle(*v8::Local<v8::Object>::Cast(res)));
  
    CHECK(CcTest::heap()->InOldSpace(o->elements()));
    CHECK(CcTest::heap()->InOldSpace(*o));
  }
  
  TEST(OptimizedPretenuringNestedInObjectProperties) {
    FLAG_allow_natives_syntax = true;
    FLAG_expose_gc = true;
    CcTest::InitializeVM();
    if (!CcTest::i_isolate()->use_optimizer() || FLAG_always_opt) return;
    if (FLAG_gc_global || FLAG_stress_compaction ||
        FLAG_stress_incremental_marking) {
      return;
    }
    v8::HandleScope scope(CcTest::isolate());
  
    // Grow new space until maximum capacity reached.
    while (!CcTest::heap()->new_space()->IsAtMaximumCapacity()) {
      CcTest::heap()->new_space()->Grow();
    }
  
    // Keep the nested literal alive while its root is freed
    i::ScopedVector<char> source(1024);
    i::SNPrintF(source,
                "let number_elements = %d;"
                "let elements = new Array(number_elements);"
                "function f() {"
                "  for (let i = 0; i < number_elements; i++) {"
                "     let l =  {a: {c: 2.2, d: {e: 3.3}}, b: 1.1}; "
                "    elements[i] = l.a;"
                "  }"
                "  return elements[number_elements-1];"
                "};"
                "%%PrepareFunctionForOptimization(f);"
                "f(); gc(); gc();"
                "f(); f();"
                "%%OptimizeFunctionOnNextCall(f);"
                "f();",
                kPretenureCreationCount);
  
    v8::Local<v8::Value> res = CompileRun(source.begin());
  
    i::Handle<JSObject> o = Handle<JSObject>::cast(
        v8::Utils::OpenHandle(*v8::Local<v8::Object>::Cast(res)));
  
    // Nested literal sites are only pretenured if the top level
    // literal is pretenured
    CHECK(Heap::InYoungGeneration(*o));
  }
  
  TEST(OptimizedPretenuringMixedInObjectProperties) {
    FLAG_allow_natives_syntax = true;
    FLAG_expose_gc = true;
    CcTest::InitializeVM();
    if (!CcTest::i_isolate()->use_optimizer() || FLAG_always_opt) return;
    if (FLAG_gc_global || FLAG_stress_compaction ||
        FLAG_stress_incremental_marking)
      return;
    v8::HandleScope scope(CcTest::isolate());
  
    // Grow new space unitl maximum capacity reached.
    while (!CcTest::heap()->new_space()->IsAtMaximumCapacity()) {
      CcTest::heap()->new_space()->Grow();
    }
  
  
    i::ScopedVector<char> source(1024);
    i::SNPrintF(source,
                "var number_elements = %d;"
                "var elements = new Array(number_elements);"
                "function f() {"
                "  for (var i = 0; i < number_elements; i++) {"
                "    elements[i] = {a: {c: 2.2, d: {}}, b: 1.1};"
                "  }"
                "  return elements[number_elements - 1];"
                "};"
                "%%PrepareFunctionForOptimization(f);"
                "f(); gc();"
                "f(); f();"
                "%%OptimizeFunctionOnNextCall(f);"
                "f();",
                kPretenureCreationCount);
  
    v8::Local<v8::Value> res = CompileRun(source.begin());
  
    i::Handle<JSObject> o = Handle<JSObject>::cast(
        v8::Utils::OpenHandle(*v8::Local<v8::Object>::Cast(res)));
  
    CHECK(CcTest::heap()->InOldSpace(*o));
    FieldIndex idx1 = FieldIndex::ForPropertyIndex(o->map(), 0);
    FieldIndex idx2 = FieldIndex::ForPropertyIndex(o->map(), 1);
    CHECK(CcTest::heap()->InOldSpace(o->RawFastPropertyAt(idx1)));
    if (!o->IsUnboxedDoubleField(idx2)) {
      CHECK(CcTest::heap()->InOldSpace(o->RawFastPropertyAt(idx2)));
    } else {
      CHECK_EQ(1.1, o->RawFastDoublePropertyAt(idx2));
    }
  
    JSObject inner_object = JSObject::cast(o->RawFastPropertyAt(idx1));
    CHECK(CcTest::heap()->InOldSpace(inner_object));
    if (!inner_object.IsUnboxedDoubleField(idx1)) {
      CHECK(CcTest::heap()->InOldSpace(inner_object.RawFastPropertyAt(idx1)));
    } else {
      CHECK_EQ(2.2, inner_object.RawFastDoublePropertyAt(idx1));
    }
    CHECK(CcTest::heap()->InOldSpace(inner_object.RawFastPropertyAt(idx2)));
  }
  
  
  TEST(OptimizedPretenuringDoubleArrayProperties) {
    FLAG_allow_natives_syntax = true;
    FLAG_expose_gc = true;
    CcTest::InitializeVM();
    if (!CcTest::i_isolate()->use_optimizer() || FLAG_always_opt) return;
    if (FLAG_gc_global || FLAG_stress_compaction ||
        FLAG_stress_incremental_marking)
      return;
    v8::HandleScope scope(CcTest::isolate());
  
    // Grow new space until maximum capacity reached.
    while (!CcTest::heap()->new_space()->IsAtMaximumCapacity()) {
      CcTest::heap()->new_space()->Grow();
    }
  
    i::ScopedVector<char> source(1024);
    i::SNPrintF(source,
                "var number_elements = %d;"
                "var elements = new Array(number_elements);"
                "function f() {"
                "  for (var i = 0; i < number_elements; i++) {"
                "    elements[i] = {a: 1.1, b: 2.2};"
                "  }"
                "  return elements[i - 1];"
                "};"
                "%%PrepareFunctionForOptimization(f);"
                "f(); gc();"
                "f(); f();"
                "%%OptimizeFunctionOnNextCall(f);"
                "f();",
                kPretenureCreationCount);
  
    v8::Local<v8::Value> res = CompileRun(source.begin());
  
    i::Handle<JSObject> o = Handle<JSObject>::cast(
        v8::Utils::OpenHandle(*v8::Local<v8::Object>::Cast(res)));
  
    CHECK(CcTest::heap()->InOldSpace(*o));
    CHECK_EQ(o->property_array(),
             ReadOnlyRoots(CcTest::heap()).empty_property_array());
  }
  
  
  TEST(OptimizedPretenuringdoubleArrayLiterals) {
    FLAG_allow_natives_syntax = true;
    FLAG_expose_gc = true;
    CcTest::InitializeVM();
    if (!CcTest::i_isolate()->use_optimizer() || FLAG_always_opt) return;
    if (FLAG_gc_global || FLAG_stress_compaction ||
        FLAG_stress_incremental_marking)
      return;
    v8::HandleScope scope(CcTest::isolate());
  
    // Grow new space unitl maximum capacity reached.
    while (!CcTest::heap()->new_space()->IsAtMaximumCapacity()) {
      CcTest::heap()->new_space()->Grow();
    }
  
    i::ScopedVector<char> source(1024);
    i::SNPrintF(source,
                "var number_elements = %d;"
                "var elements = new Array(number_elements);"
                "function f() {"
                "  for (var i = 0; i < number_elements; i++) {"
                "    elements[i] = [1.1, 2.2, 3.3];"
                "  }"
                "  return elements[number_elements - 1];"
                "};"
                "%%PrepareFunctionForOptimization(f);"
                "f(); gc();"
                "f(); f();"
                "%%OptimizeFunctionOnNextCall(f);"
                "f();",
                kPretenureCreationCount);
  
    v8::Local<v8::Value> res = CompileRun(source.begin());
  
    i::Handle<JSObject> o = Handle<JSObject>::cast(
        v8::Utils::OpenHandle(*v8::Local<v8::Object>::Cast(res)));
  
    CHECK(CcTest::heap()->InOldSpace(o->elements()));
    CHECK(CcTest::heap()->InOldSpace(*o));
  }
  
  
  TEST(OptimizedPretenuringNestedMixedArrayLiterals) {
    FLAG_allow_natives_syntax = true;
    FLAG_expose_gc = true;
    CcTest::InitializeVM();
    if (!CcTest::i_isolate()->use_optimizer() || FLAG_always_opt) return;
    if (FLAG_gc_global || FLAG_stress_compaction ||
        FLAG_stress_incremental_marking)
      return;
    v8::HandleScope scope(CcTest::isolate());
    v8::Local<v8::Context> ctx = CcTest::isolate()->GetCurrentContext();
    // Grow new space unitl maximum capacity reached.
    while (!CcTest::heap()->new_space()->IsAtMaximumCapacity()) {
      CcTest::heap()->new_space()->Grow();
    }
  
    i::ScopedVector<char> source(1024);
    i::SNPrintF(source,
                "var number_elements = %d;"
                "var elements = new Array(number_elements);"
                "function f() {"
                "  for (var i = 0; i < number_elements; i++) {"
                "    elements[i] = [[{}, {}, {}], [1.1, 2.2, 3.3]];"
                "  }"
                "  return elements[number_elements - 1];"
                "};"
                "%%PrepareFunctionForOptimization(f);"
                "f(); gc();"
                "f(); f();"
                "%%OptimizeFunctionOnNextCall(f);"
                "f();",
                kPretenureCreationCount);
  
    v8::Local<v8::Value> res = CompileRun(source.begin());
  
    v8::Local<v8::Value> int_array =
        v8::Object::Cast(*res)->Get(ctx, v8_str("0")).ToLocalChecked();
    i::Handle<JSObject> int_array_handle = i::Handle<JSObject>::cast(
        v8::Utils::OpenHandle(*v8::Local<v8::Object>::Cast(int_array)));
    v8::Local<v8::Value> double_array =
        v8::Object::Cast(*res)->Get(ctx, v8_str("1")).ToLocalChecked();
    i::Handle<JSObject> double_array_handle = i::Handle<JSObject>::cast(
        v8::Utils::OpenHandle(*v8::Local<v8::Object>::Cast(double_array)));
  
    Handle<JSObject> o = Handle<JSObject>::cast(
        v8::Utils::OpenHandle(*v8::Local<v8::Object>::Cast(res)));
    CHECK(CcTest::heap()->InOldSpace(*o));
    CHECK(CcTest::heap()->InOldSpace(*int_array_handle));
    CHECK(CcTest::heap()->InOldSpace(int_array_handle->elements()));
    CHECK(CcTest::heap()->InOldSpace(*double_array_handle));
    CHECK(CcTest::heap()->InOldSpace(double_array_handle->elements()));
  }
  
  
  TEST(OptimizedPretenuringNestedObjectLiterals) {
    FLAG_allow_natives_syntax = true;
    FLAG_expose_gc = true;
    CcTest::InitializeVM();
    if (!CcTest::i_isolate()->use_optimizer() || FLAG_always_opt) return;
    if (FLAG_gc_global || FLAG_stress_compaction ||
        FLAG_stress_incremental_marking)
      return;
    v8::HandleScope scope(CcTest::isolate());
    v8::Local<v8::Context> ctx = CcTest::isolate()->GetCurrentContext();
    // Grow new space unitl maximum capacity reached.
    while (!CcTest::heap()->new_space()->IsAtMaximumCapacity()) {
      CcTest::heap()->new_space()->Grow();
    }
  
    i::ScopedVector<char> source(1024);
    i::SNPrintF(source,
                "var number_elements = %d;"
                "var elements = new Array(number_elements);"
                "function f() {"
                "  for (var i = 0; i < number_elements; i++) {"
                "    elements[i] = [[{}, {}, {}],[{}, {}, {}]];"
                "  }"
                "  return elements[number_elements - 1];"
                "};"
                "%%PrepareFunctionForOptimization(f);"
                "f(); gc();"
                "f(); f();"
                "%%OptimizeFunctionOnNextCall(f);"
                "f();",
                kPretenureCreationCount);
  
    v8::Local<v8::Value> res = CompileRun(source.begin());
  
    v8::Local<v8::Value> int_array_1 =
        v8::Object::Cast(*res)->Get(ctx, v8_str("0")).ToLocalChecked();
    Handle<JSObject> int_array_handle_1 = Handle<JSObject>::cast(
        v8::Utils::OpenHandle(*v8::Local<v8::Object>::Cast(int_array_1)));
    v8::Local<v8::Value> int_array_2 =
        v8::Object::Cast(*res)->Get(ctx, v8_str("1")).ToLocalChecked();
    Handle<JSObject> int_array_handle_2 = Handle<JSObject>::cast(
        v8::Utils::OpenHandle(*v8::Local<v8::Object>::Cast(int_array_2)));
  
    Handle<JSObject> o = Handle<JSObject>::cast(
        v8::Utils::OpenHandle(*v8::Local<v8::Object>::Cast(res)));
    CHECK(CcTest::heap()->InOldSpace(*o));
    CHECK(CcTest::heap()->InOldSpace(*int_array_handle_1));
    CHECK(CcTest::heap()->InOldSpace(int_array_handle_1->elements()));
    CHECK(CcTest::heap()->InOldSpace(*int_array_handle_2));
    CHECK(CcTest::heap()->InOldSpace(int_array_handle_2->elements()));
  }
  
  
  TEST(OptimizedPretenuringNestedDoubleLiterals) {
    FLAG_allow_natives_syntax = true;
    FLAG_expose_gc = true;
    CcTest::InitializeVM();
    if (!CcTest::i_isolate()->use_optimizer() || FLAG_always_opt) return;
    if (FLAG_gc_global || FLAG_stress_compaction ||
        FLAG_stress_incremental_marking)
      return;
    v8::HandleScope scope(CcTest::isolate());
    v8::Local<v8::Context> ctx = CcTest::isolate()->GetCurrentContext();
    // Grow new space unitl maximum capacity reached.
    while (!CcTest::heap()->new_space()->IsAtMaximumCapacity()) {
      CcTest::heap()->new_space()->Grow();
    }
  
    i::ScopedVector<char> source(1024);
    i::SNPrintF(source,
                "var number_elements = %d;"
                "var elements = new Array(number_elements);"
                "function f() {"
                "  for (var i = 0; i < number_elements; i++) {"
                "    elements[i] = [[1.1, 1.2, 1.3],[2.1, 2.2, 2.3]];"
                "  }"
                "  return elements[number_elements - 1];"
                "};"
                "%%PrepareFunctionForOptimization(f);"
                "f(); gc();"
                "f(); f();"
                "%%OptimizeFunctionOnNextCall(f);"
                "f();",
                kPretenureCreationCount);
  
    v8::Local<v8::Value> res = CompileRun(source.begin());
  
    v8::Local<v8::Value> double_array_1 =
        v8::Object::Cast(*res)->Get(ctx, v8_str("0")).ToLocalChecked();
    i::Handle<JSObject> double_array_handle_1 = i::Handle<JSObject>::cast(
        v8::Utils::OpenHandle(*v8::Local<v8::Object>::Cast(double_array_1)));
    v8::Local<v8::Value> double_array_2 =
        v8::Object::Cast(*res)->Get(ctx, v8_str("1")).ToLocalChecked();
    i::Handle<JSObject> double_array_handle_2 = Handle<JSObject>::cast(
        v8::Utils::OpenHandle(*v8::Local<v8::Object>::Cast(double_array_2)));
  
    i::Handle<JSObject> o = Handle<JSObject>::cast(
        v8::Utils::OpenHandle(*v8::Local<v8::Object>::Cast(res)));
    CHECK(CcTest::heap()->InOldSpace(*o));
    CHECK(CcTest::heap()->InOldSpace(*double_array_handle_1));
    CHECK(CcTest::heap()->InOldSpace(double_array_handle_1->elements()));
    CHECK(CcTest::heap()->InOldSpace(*double_array_handle_2));
    CHECK(CcTest::heap()->InOldSpace(double_array_handle_2->elements()));
  }
  
  
  // Test regular array literals allocation.
  TEST(OptimizedAllocationArrayLiterals) {
    FLAG_allow_natives_syntax = true;
    CcTest::InitializeVM();
    if (!CcTest::i_isolate()->use_optimizer() || FLAG_always_opt) return;
    if (FLAG_gc_global || FLAG_stress_compaction ||
        FLAG_stress_incremental_marking)
      return;
    v8::HandleScope scope(CcTest::isolate());
    v8::Local<v8::Context> ctx = CcTest::isolate()->GetCurrentContext();
    v8::Local<v8::Value> res = CompileRun(
        "function f() {"
        "  var numbers = new Array(1, 2, 3);"
        "  numbers[0] = 3.14;"
        "  return numbers;"
        "};"
        "%PrepareFunctionForOptimization(f);"
        "f(); f(); f();"
        "%OptimizeFunctionOnNextCall(f);"
        "f();");
    CHECK_EQ(static_cast<int>(3.14), v8::Object::Cast(*res)
                                         ->Get(ctx, v8_str("0"))
                                         .ToLocalChecked()
                                         ->Int32Value(ctx)
                                         .FromJust());
  
    i::Handle<JSObject> o = Handle<JSObject>::cast(
        v8::Utils::OpenHandle(*v8::Local<v8::Object>::Cast(res)));
  
    CHECK(Heap::InYoungGeneration(o->elements()));
  }
  
  static int CountMapTransitions(i::Isolate* isolate, Map map) {
    DisallowHeapAllocation no_gc;
    return TransitionsAccessor(isolate, map, &no_gc).NumberOfTransitions();
  }
  
  
  // Test that map transitions are cleared and maps are collected with
  // incremental marking as well.
  TEST(Regress1465) {
    if (!FLAG_incremental_marking) return;
    FLAG_stress_compaction = false;
    FLAG_stress_incremental_marking = false;
    FLAG_allow_natives_syntax = true;
    FLAG_trace_incremental_marking = true;
    FLAG_retain_maps_for_n_gc = 0;
    CcTest::InitializeVM();
    v8::Isolate* isolate = CcTest::isolate();
    i::Isolate* i_isolate = CcTest::i_isolate();
    v8::HandleScope scope(isolate);
    v8::Local<v8::Context> ctx = isolate->GetCurrentContext();
    static const int transitions_count = 256;
  
    CompileRun("function F() {}");
    {
      AlwaysAllocateScope always_allocate(CcTest::i_isolate());
      for (int i = 0; i < transitions_count; i++) {
        EmbeddedVector<char, 64> buffer;
        SNPrintF(buffer, "var o = new F; o.prop%d = %d;", i, i);
        CompileRun(buffer.begin());
      }
      CompileRun("var root = new F;");
    }
  
    i::Handle<JSReceiver> root =
        v8::Utils::OpenHandle(*v8::Local<v8::Object>::Cast(
            CcTest::global()->Get(ctx, v8_str("root")).ToLocalChecked()));
  
    // Count number of live transitions before marking.
    int transitions_before = CountMapTransitions(i_isolate, root->map());
    CompileRun("%DebugPrint(root);");
    CHECK_EQ(transitions_count, transitions_before);
  
    heap::SimulateIncrementalMarking(CcTest::heap());
    CcTest::CollectAllGarbage();
  
    // Count number of live transitions after marking.  Note that one transition
    // is left, because 'o' still holds an instance of one transition target.
    int transitions_after = CountMapTransitions(i_isolate, root->map());
    CompileRun("%DebugPrint(root);");
    CHECK_EQ(1, transitions_after);
  }
  
  static i::Handle<JSObject> GetByName(const char* name) {
    return i::Handle<JSObject>::cast(
        v8::Utils::OpenHandle(*v8::Local<v8::Object>::Cast(
            CcTest::global()
                ->Get(CcTest::isolate()->GetCurrentContext(), v8_str(name))
                .ToLocalChecked())));
  }
  
  #ifdef DEBUG
  static void AddTransitions(int transitions_count) {
    AlwaysAllocateScope always_allocate(CcTest::i_isolate());
    for (int i = 0; i < transitions_count; i++) {
      EmbeddedVector<char, 64> buffer;
      SNPrintF(buffer, "var o = new F; o.prop%d = %d;", i, i);
      CompileRun(buffer.begin());
    }
  }
  
  
  static void AddPropertyTo(
      int gc_count, Handle<JSObject> object, const char* property_name) {
    Isolate* isolate = CcTest::i_isolate();
    Factory* factory = isolate->factory();
    Handle<String> prop_name = factory->InternalizeUtf8String(property_name);
    Handle<Smi> twenty_three(Smi::FromInt(23), isolate);
    FLAG_gc_interval = gc_count;
    FLAG_gc_global = true;
    FLAG_retain_maps_for_n_gc = 0;
    CcTest::heap()->set_allocation_timeout(gc_count);
    Object::SetProperty(isolate, object, prop_name, twenty_three).Check();
  }
  
  
  TEST(TransitionArrayShrinksDuringAllocToZero) {
    FLAG_stress_compaction = false;
    FLAG_stress_incremental_marking = false;
    FLAG_allow_natives_syntax = true;
    CcTest::InitializeVM();
    i::Isolate* i_isolate = CcTest::i_isolate();
    v8::HandleScope scope(CcTest::isolate());
    static const int transitions_count = 10;
    CompileRun("function F() { }");
    AddTransitions(transitions_count);
    CompileRun("var root = new F;");
    Handle<JSObject> root = GetByName("root");
  
    // Count number of live transitions before marking.
    int transitions_before = CountMapTransitions(i_isolate, root->map());
    CHECK_EQ(transitions_count, transitions_before);
  
    // Get rid of o
    CompileRun("o = new F;"
               "root = new F");
    root = GetByName("root");
    AddPropertyTo(2, root, "funny");
    CcTest::CollectGarbage(NEW_SPACE);
  
    // Count number of live transitions after marking.  Note that one transition
    // is left, because 'o' still holds an instance of one transition target.
    int transitions_after =
        CountMapTransitions(i_isolate, Map::cast(root->map().GetBackPointer()));
    CHECK_EQ(1, transitions_after);
  }
  
  
  TEST(TransitionArrayShrinksDuringAllocToOne) {
    FLAG_stress_compaction = false;
    FLAG_stress_incremental_marking = false;
    FLAG_allow_natives_syntax = true;
    CcTest::InitializeVM();
    i::Isolate* i_isolate = CcTest::i_isolate();
    v8::HandleScope scope(CcTest::isolate());
    static const int transitions_count = 10;
    CompileRun("function F() {}");
    AddTransitions(transitions_count);
    CompileRun("var root = new F;");
    Handle<JSObject> root = GetByName("root");
  
    // Count number of live transitions before marking.
    int transitions_before = CountMapTransitions(i_isolate, root->map());
    CHECK_EQ(transitions_count, transitions_before);
  
    root = GetByName("root");
    AddPropertyTo(2, root, "funny");
    CcTest::CollectGarbage(NEW_SPACE);
  
    // Count number of live transitions after marking.  Note that one transition
    // is left, because 'o' still holds an instance of one transition target.
    int transitions_after =
        CountMapTransitions(i_isolate, Map::cast(root->map().GetBackPointer()));
    CHECK_EQ(2, transitions_after);
  }
  
  
  TEST(TransitionArrayShrinksDuringAllocToOnePropertyFound) {
    FLAG_stress_compaction = false;
    FLAG_stress_incremental_marking = false;
    FLAG_allow_natives_syntax = true;
    CcTest::InitializeVM();
    i::Isolate* i_isolate = CcTest::i_isolate();
    v8::HandleScope scope(CcTest::isolate());
    static const int transitions_count = 10;
    CompileRun("function F() {}");
    AddTransitions(transitions_count);
    CompileRun("var root = new F;");
    Handle<JSObject> root = GetByName("root");
  
    // Count number of live transitions before marking.
    int transitions_before = CountMapTransitions(i_isolate, root->map());
    CHECK_EQ(transitions_count, transitions_before);
  
    root = GetByName("root");
    AddPropertyTo(0, root, "prop9");
    CcTest::CollectGarbage(OLD_SPACE);
  
    // Count number of live transitions after marking.  Note that one transition
    // is left, because 'o' still holds an instance of one transition target.
    int transitions_after =
        CountMapTransitions(i_isolate, Map::cast(root->map().GetBackPointer()));
    CHECK_EQ(1, transitions_after);
  }
  #endif  // DEBUG
  
  
  TEST(ReleaseOverReservedPages) {
    if (FLAG_never_compact) return;
    FLAG_trace_gc = true;
    // The optimizer can allocate stuff, messing up the test.
  #ifndef V8_LITE_MODE
    FLAG_opt = false;
    FLAG_always_opt = false;
  #endif  // V8_LITE_MODE
    // - Parallel compaction increases fragmentation, depending on how existing
    //   memory is distributed. Since this is non-deterministic because of
    //   concurrent sweeping, we disable it for this test.
    // - Concurrent sweeping adds non determinism, depending on when memory is
    //   available for further reuse.
    // - Fast evacuation of pages may result in a different page count in old
    //   space.
    ManualGCScope manual_gc_scope;
    FLAG_page_promotion = false;
    FLAG_parallel_compaction = false;
    CcTest::InitializeVM();
    Isolate* isolate = CcTest::i_isolate();
    // If there's snapshot available, we don't know whether 20 small arrays will
    // fit on the initial pages.
    if (!isolate->snapshot_available()) return;
    Factory* factory = isolate->factory();
    Heap* heap = isolate->heap();
    v8::HandleScope scope(CcTest::isolate());
    // Ensure that the young generation is empty.
    CcTest::CollectGarbage(NEW_SPACE);
    CcTest::CollectGarbage(NEW_SPACE);
    static const int number_of_test_pages = 20;
  
    // Prepare many pages with low live-bytes count.
    PagedSpace* old_space = heap->old_space();
    const int initial_page_count = old_space->CountTotalPages();
    const int overall_page_count = number_of_test_pages + initial_page_count;
    for (int i = 0; i < number_of_test_pages; i++) {
      AlwaysAllocateScope always_allocate(isolate);
      heap::SimulateFullSpace(old_space);
      factory->NewFixedArray(1, AllocationType::kOld);
    }
    CHECK_EQ(overall_page_count, old_space->CountTotalPages());
  
    // Triggering one GC will cause a lot of garbage to be discovered but
    // even spread across all allocated pages.
    CcTest::CollectAllGarbage();
    CHECK_GE(overall_page_count, old_space->CountTotalPages());
  
    // Triggering subsequent GCs should cause at least half of the pages
    // to be released to the OS after at most two cycles.
    CcTest::CollectAllGarbage();
    CHECK_GE(overall_page_count, old_space->CountTotalPages());
    CcTest::CollectAllGarbage();
    CHECK_GE(overall_page_count, old_space->CountTotalPages() * 2);
  
    // Triggering a last-resort GC should cause all pages to be released to the
    // OS so that other processes can seize the memory.  If we get a failure here
    // where there are 2 pages left instead of 1, then we should increase the
    // size of the first page a little in SizeOfFirstPage in spaces.cc.  The
    // first page should be small in order to reduce memory used when the VM
    // boots, but if the 20 small arrays don't fit on the first page then that's
    // an indication that it is too small.
    CcTest::CollectAllAvailableGarbage();
    CHECK_GE(initial_page_count, old_space->CountTotalPages());
  }
  
  static int forced_gc_counter = 0;
  
  void MockUseCounterCallback(v8::Isolate* isolate,
                              v8::Isolate::UseCounterFeature feature) {
    isolate->GetCurrentContext();
    if (feature == v8::Isolate::kForcedGC) {
      forced_gc_counter++;
    }
  }
  
  
  TEST(CountForcedGC) {
    FLAG_expose_gc = true;
    CcTest::InitializeVM();
    Isolate* isolate = CcTest::i_isolate();
    v8::HandleScope scope(CcTest::isolate());
  
    isolate->SetUseCounterCallback(MockUseCounterCallback);
  
    forced_gc_counter = 0;
    const char* source = "gc();";
    CompileRun(source);
    CHECK_GT(forced_gc_counter, 0);
  }
  
  
  #ifdef OBJECT_PRINT
  TEST(PrintSharedFunctionInfo) {
    CcTest::InitializeVM();
    v8::HandleScope scope(CcTest::isolate());
    v8::Local<v8::Context> ctx = CcTest::isolate()->GetCurrentContext();
    const char* source = "f = function() { return 987654321; }\n"
                         "g = function() { return 123456789; }\n";
    CompileRun(source);
    i::Handle<JSFunction> g = i::Handle<JSFunction>::cast(
        v8::Utils::OpenHandle(*v8::Local<v8::Function>::Cast(
            CcTest::global()->Get(ctx, v8_str("g")).ToLocalChecked())));
  
    StdoutStream os;
    g->shared().Print(os);
    os << std::endl;
  }
  #endif  // OBJECT_PRINT
  
  
  TEST(IncrementalMarkingPreservesMonomorphicCallIC) {
    if (!FLAG_use_ic) return;
    if (!FLAG_incremental_marking) return;
    if (FLAG_always_opt) return;
    FLAG_allow_natives_syntax = true;
    CcTest::InitializeVM();
    v8::HandleScope scope(CcTest::isolate());
    v8::Local<v8::Value> fun1, fun2;
    v8::Local<v8::Context> ctx = CcTest::isolate()->GetCurrentContext();
    {
      CompileRun("function fun() {};");
      fun1 = CcTest::global()->Get(ctx, v8_str("fun")).ToLocalChecked();
    }
  
    {
      CompileRun("function fun() {};");
      fun2 = CcTest::global()->Get(ctx, v8_str("fun")).ToLocalChecked();
    }
  
    // Prepare function f that contains type feedback for the two closures.
    CHECK(CcTest::global()->Set(ctx, v8_str("fun1"), fun1).FromJust());
    CHECK(CcTest::global()->Set(ctx, v8_str("fun2"), fun2).FromJust());
    CompileRun(
        "function f(a, b) { a(); b(); } %EnsureFeedbackVectorForFunction(f); "
        "f(fun1, fun2);");
  
    Handle<JSFunction> f = Handle<JSFunction>::cast(
        v8::Utils::OpenHandle(*v8::Local<v8::Function>::Cast(
            CcTest::global()->Get(ctx, v8_str("f")).ToLocalChecked())));
  
    Handle<FeedbackVector> feedback_vector(f->feedback_vector(), f->GetIsolate());
    FeedbackVectorHelper feedback_helper(feedback_vector);
  
    int expected_slots = 2;
    CHECK_EQ(expected_slots, feedback_helper.slot_count());
    int slot1 = 0;
    int slot2 = 1;
    CHECK(feedback_vector->Get(feedback_helper.slot(slot1))->IsWeak());
    CHECK(feedback_vector->Get(feedback_helper.slot(slot2))->IsWeak());
  
    heap::SimulateIncrementalMarking(CcTest::heap());
    CcTest::CollectAllGarbage();
  
    CHECK(feedback_vector->Get(feedback_helper.slot(slot1))->IsWeak());
    CHECK(feedback_vector->Get(feedback_helper.slot(slot2))->IsWeak());
  }
  
  
  static void CheckVectorIC(Handle<JSFunction> f, int slot_index,
                            InlineCacheState desired_state) {
    Handle<FeedbackVector> vector =
        Handle<FeedbackVector>(f->feedback_vector(), f->GetIsolate());
    FeedbackVectorHelper helper(vector);
    FeedbackSlot slot = helper.slot(slot_index);
    FeedbackNexus nexus(vector, slot);
    CHECK(nexus.ic_state() == desired_state);
  }
  
  TEST(IncrementalMarkingPreservesMonomorphicConstructor) {
    if (!FLAG_incremental_marking) return;
    if (FLAG_always_opt) return;
    FLAG_allow_natives_syntax = true;
    CcTest::InitializeVM();
    v8::HandleScope scope(CcTest::isolate());
    v8::Local<v8::Context> ctx = CcTest::isolate()->GetCurrentContext();
    // Prepare function f that contains a monomorphic IC for object
    // originating from the same native context.
    CompileRun(
        "function fun() { this.x = 1; };"
        "function f(o) { return new o(); }"
        "%EnsureFeedbackVectorForFunction(f);"
        "f(fun); f(fun);");
    Handle<JSFunction> f = Handle<JSFunction>::cast(
        v8::Utils::OpenHandle(*v8::Local<v8::Function>::Cast(
            CcTest::global()->Get(ctx, v8_str("f")).ToLocalChecked())));
  
    Handle<FeedbackVector> vector(f->feedback_vector(), f->GetIsolate());
    CHECK(vector->Get(FeedbackSlot(0))->IsWeakOrCleared());
  
    heap::SimulateIncrementalMarking(CcTest::heap());
    CcTest::CollectAllGarbage();
  
    CHECK(vector->Get(FeedbackSlot(0))->IsWeakOrCleared());
  }
  
  TEST(IncrementalMarkingPreservesMonomorphicIC) {
    if (!FLAG_use_ic) return;
    if (!FLAG_incremental_marking) return;
    if (FLAG_always_opt) return;
    FLAG_allow_natives_syntax = true;
    CcTest::InitializeVM();
    v8::HandleScope scope(CcTest::isolate());
    v8::Local<v8::Context> ctx = CcTest::isolate()->GetCurrentContext();
    // Prepare function f that contains a monomorphic IC for object
    // originating from the same native context.
    CompileRun(
        "function fun() { this.x = 1; }; var obj = new fun();"
        "%EnsureFeedbackVectorForFunction(f);"
        "function f(o) { return o.x; } f(obj); f(obj);");
    Handle<JSFunction> f = Handle<JSFunction>::cast(
        v8::Utils::OpenHandle(*v8::Local<v8::Function>::Cast(
            CcTest::global()->Get(ctx, v8_str("f")).ToLocalChecked())));
  
    CheckVectorIC(f, 0, MONOMORPHIC);
  
    heap::SimulateIncrementalMarking(CcTest::heap());
    CcTest::CollectAllGarbage();
  
    CheckVectorIC(f, 0, MONOMORPHIC);
  }
  
  TEST(IncrementalMarkingPreservesPolymorphicIC) {
    if (!FLAG_use_ic) return;
    if (!FLAG_incremental_marking) return;
    if (FLAG_always_opt) return;
    FLAG_allow_natives_syntax = true;
    CcTest::InitializeVM();
    v8::HandleScope scope(CcTest::isolate());
    v8::Local<v8::Value> obj1, obj2;
    v8::Local<v8::Context> ctx = CcTest::isolate()->GetCurrentContext();
  
    {
      LocalContext env;
      CompileRun("function fun() { this.x = 1; }; var obj = new fun();");
      obj1 = env->Global()->Get(env.local(), v8_str("obj")).ToLocalChecked();
    }
  
    {
      LocalContext env;
      CompileRun("function fun() { this.x = 2; }; var obj = new fun();");
      obj2 = env->Global()->Get(env.local(), v8_str("obj")).ToLocalChecked();
    }
  
    // Prepare function f that contains a polymorphic IC for objects
    // originating from two different native contexts.
    CHECK(CcTest::global()->Set(ctx, v8_str("obj1"), obj1).FromJust());
    CHECK(CcTest::global()->Set(ctx, v8_str("obj2"), obj2).FromJust());
    CompileRun(
        "function f(o) { return o.x; }; "
        "%EnsureFeedbackVectorForFunction(f);"
        "f(obj1); f(obj1); f(obj2);");
    Handle<JSFunction> f = Handle<JSFunction>::cast(
        v8::Utils::OpenHandle(*v8::Local<v8::Function>::Cast(
            CcTest::global()->Get(ctx, v8_str("f")).ToLocalChecked())));
  
    CheckVectorIC(f, 0, POLYMORPHIC);
  
    // Fire context dispose notification.
    heap::SimulateIncrementalMarking(CcTest::heap());
    CcTest::CollectAllGarbage();
  
    CheckVectorIC(f, 0, POLYMORPHIC);
  }
  
  TEST(ContextDisposeDoesntClearPolymorphicIC) {
    if (!FLAG_use_ic) return;
    if (!FLAG_incremental_marking) return;
    if (FLAG_always_opt) return;
    FLAG_allow_natives_syntax = true;
    CcTest::InitializeVM();
    v8::HandleScope scope(CcTest::isolate());
    v8::Local<v8::Value> obj1, obj2;
    v8::Local<v8::Context> ctx = CcTest::isolate()->GetCurrentContext();
  
    {
      LocalContext env;
      CompileRun("function fun() { this.x = 1; }; var obj = new fun();");
      obj1 = env->Global()->Get(env.local(), v8_str("obj")).ToLocalChecked();
    }
  
    {
      LocalContext env;
      CompileRun("function fun() { this.x = 2; }; var obj = new fun();");
      obj2 = env->Global()->Get(env.local(), v8_str("obj")).ToLocalChecked();
    }
  
    // Prepare function f that contains a polymorphic IC for objects
    // originating from two different native contexts.
    CHECK(CcTest::global()->Set(ctx, v8_str("obj1"), obj1).FromJust());
    CHECK(CcTest::global()->Set(ctx, v8_str("obj2"), obj2).FromJust());
    CompileRun(
        "function f(o) { return o.x; }; "
        "%EnsureFeedbackVectorForFunction(f);"
        "f(obj1); f(obj1); f(obj2);");
    Handle<JSFunction> f = Handle<JSFunction>::cast(
        v8::Utils::OpenHandle(*v8::Local<v8::Function>::Cast(
            CcTest::global()->Get(ctx, v8_str("f")).ToLocalChecked())));
  
    CheckVectorIC(f, 0, POLYMORPHIC);
  
    // Fire context dispose notification.
    CcTest::isolate()->ContextDisposedNotification();
    heap::SimulateIncrementalMarking(CcTest::heap());
    CcTest::CollectAllGarbage();
  
    CheckVectorIC(f, 0, POLYMORPHIC);
  }
  
  
  class SourceResource : public v8::String::ExternalOneByteStringResource {
   public:
    explicit SourceResource(const char* data)
      : data_(data), length_(strlen(data)) { }
  
    void Dispose() override {
      i::DeleteArray(data_);
      data_ = nullptr;
    }
  
    const char* data() const override { return data_; }
  
    size_t length() const override { return length_; }
  
    bool IsDisposed() { return data_ == nullptr; }
  
   private:
    const char* data_;
    size_t length_;
  };
  
  
  void ReleaseStackTraceDataTest(v8::Isolate* isolate, const char* source,
                                 const char* accessor) {
    // Test that the data retained by the Error.stack accessor is released
    // after the first time the accessor is fired.  We use external string
    // to check whether the data is being released since the external string
    // resource's callback is fired when the external string is GC'ed.
    i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
    v8::HandleScope scope(isolate);
    SourceResource* resource = new SourceResource(i::StrDup(source));
    {
      v8::HandleScope scope(isolate);
      v8::Local<v8::Context> ctx = isolate->GetCurrentContext();
      v8::Local<v8::String> source_string =
          v8::String::NewExternalOneByte(isolate, resource).ToLocalChecked();
      i_isolate->heap()->CollectAllAvailableGarbage(
          i::GarbageCollectionReason::kTesting);
      v8::Script::Compile(ctx, source_string)
          .ToLocalChecked()
          ->Run(ctx)
          .ToLocalChecked();
      CHECK(!resource->IsDisposed());
    }
    // i_isolate->heap()->CollectAllAvailableGarbage();
    CHECK(!resource->IsDisposed());
  
    CompileRun(accessor);
    i_isolate->heap()->CollectAllAvailableGarbage(
        i::GarbageCollectionReason::kTesting);
  
    // External source has been released.
    CHECK(resource->IsDisposed());
    delete resource;
  }
  
  
  UNINITIALIZED_TEST(ReleaseStackTraceData) {
    if (FLAG_always_opt) {
      // TODO(ulan): Remove this once the memory leak via code_next_link is fixed.
      // See: https://codereview.chromium.org/181833004/
      return;
    }
  #ifndef V8_LITE_MODE
    // ICs retain objects.
    FLAG_use_ic = false;
  #endif  // V8_LITE_MODE
    FLAG_concurrent_recompilation = false;
    v8::Isolate::CreateParams create_params;
    create_params.array_buffer_allocator = CcTest::array_buffer_allocator();
    v8::Isolate* isolate = v8::Isolate::New(create_params);
    {
      v8::Isolate::Scope isolate_scope(isolate);
      v8::HandleScope handle_scope(isolate);
      v8::Context::New(isolate)->Enter();
      static const char* source1 = "var error = null;            "
      /* Normal Error */           "try {                        "
                                   "  throw new Error();         "
                                   "} catch (e) {                "
                                   "  error = e;                 "
                                   "}                            ";
      static const char* source2 = "var error = null;            "
      /* Stack overflow */         "try {                        "
                                   "  (function f() { f(); })(); "
                                   "} catch (e) {                "
                                   "  error = e;                 "
                                   "}                            ";
      static const char* source3 = "var error = null;            "
      /* Normal Error */           "try {                        "
      /* as prototype */           "  throw new Error();         "
                                   "} catch (e) {                "
                                   "  error = {};                "
                                   "  error.__proto__ = e;       "
                                   "}                            ";
      static const char* source4 = "var error = null;            "
      /* Stack overflow */         "try {                        "
      /* as prototype   */         "  (function f() { f(); })(); "
                                   "} catch (e) {                "
                                   "  error = {};                "
                                   "  error.__proto__ = e;       "
                                   "}                            ";
      static const char* getter = "error.stack";
      static const char* setter = "error.stack = 0";
  
      ReleaseStackTraceDataTest(isolate, source1, setter);
      ReleaseStackTraceDataTest(isolate, source2, setter);
      // We do not test source3 and source4 with setter, since the setter is
      // supposed to (untypically) write to the receiver, not the holder.  This is
      // to emulate the behavior of a data property.
  
      ReleaseStackTraceDataTest(isolate, source1, getter);
      ReleaseStackTraceDataTest(isolate, source2, getter);
      ReleaseStackTraceDataTest(isolate, source3, getter);
      ReleaseStackTraceDataTest(isolate, source4, getter);
    }
    isolate->Dispose();
  }
  
  // TODO(mmarchini) also write tests for async/await and Promise.all
  void DetailedErrorStackTraceTest(const char* src,
                                   std::function<void(Handle<FrameArray>)> test) {
    FLAG_detailed_error_stack_trace = true;
    CcTest::InitializeVM();
    v8::HandleScope scope(CcTest::isolate());
  
    v8::TryCatch try_catch(CcTest::isolate());
    CompileRun(src);
  
    CHECK(try_catch.HasCaught());
    Handle<Object> exception = v8::Utils::OpenHandle(*try_catch.Exception());
  
    Isolate* isolate = CcTest::i_isolate();
    Handle<Name> key = isolate->factory()->stack_trace_symbol();
  
    Handle<FixedArray> stack_trace(Handle<FixedArray>::cast(
        Object::GetProperty(isolate, exception, key).ToHandleChecked()));
  
    test(GetFrameArrayFromStackTrace(isolate, stack_trace));
  }
  
  // * Test interpreted function error
  TEST(DetailedErrorStackTrace) {
    static const char* source =
        "function func1(arg1) {       "
        "  let err = new Error();     "
        "  throw err;                 "
        "}                            "
        "function func2(arg1, arg2) { "
        "  func1(42);                 "
        "}                            "
        "class Foo {};                "
        "function main(arg1, arg2) {  "
        "  func2(arg1, false);        "
        "}                            "
        "var foo = new Foo();         "
        "main(foo);                   ";
  
    DetailedErrorStackTraceTest(source, [](Handle<FrameArray> stack_trace) {
      FixedArray foo_parameters = stack_trace->Parameters(0);
      CHECK_EQ(foo_parameters.length(), 1);
      CHECK(foo_parameters.get(0).IsSmi());
      CHECK_EQ(Smi::ToInt(foo_parameters.get(0)), 42);
  
      FixedArray bar_parameters = stack_trace->Parameters(1);
      CHECK_EQ(bar_parameters.length(), 2);
      CHECK(bar_parameters.get(0).IsJSObject());
      CHECK(bar_parameters.get(1).IsBoolean());
      Handle<Object> foo = Handle<Object>::cast(GetByName("foo"));
      CHECK_EQ(bar_parameters.get(0), *foo);
      CHECK(!bar_parameters.get(1).BooleanValue(CcTest::i_isolate()));
  
      FixedArray main_parameters = stack_trace->Parameters(2);
      CHECK_EQ(main_parameters.length(), 2);
      CHECK(main_parameters.get(0).IsJSObject());
      CHECK(main_parameters.get(1).IsUndefined());
      CHECK_EQ(main_parameters.get(0), *foo);
    });
  }
  
  // * Test optimized function with inline frame error
  TEST(DetailedErrorStackTraceInline) {
    FLAG_allow_natives_syntax = true;
    static const char* source =
        "function add(x) {                     "
        " if (x == 42)                         "
        "  throw new Error();                  "
        " return x + x;                        "
        "}                                     "
        "add(0);                               "
        "add(1);                               "
        "function foo(x) {                     "
        " return add(x + 1)                    "
        "}                                     "
        "%PrepareFunctionForOptimization(foo); "
        "foo(40);                              "
        "%OptimizeFunctionOnNextCall(foo);     "
        "foo(41);                              ";
  
    DetailedErrorStackTraceTest(source, [](Handle<FrameArray> stack_trace) {
      FixedArray parameters_add = stack_trace->Parameters(0);
      CHECK_EQ(parameters_add.length(), 1);
      CHECK(parameters_add.get(0).IsSmi());
      CHECK_EQ(Smi::ToInt(parameters_add.get(0)), 42);
  
      FixedArray parameters_foo = stack_trace->Parameters(1);
      CHECK_EQ(parameters_foo.length(), 1);
      CHECK(parameters_foo.get(0).IsSmi());
      CHECK_EQ(Smi::ToInt(parameters_foo.get(0)), 41);
    });
  }
  
  // * Test builtin exit error
  TEST(DetailedErrorStackTraceBuiltinExit) {
    static const char* source =
        "function test(arg1) {           "
        "  (new Number()).toFixed(arg1); "
        "}                               "
        "test(9999);                     ";
  
    DetailedErrorStackTraceTest(source, [](Handle<FrameArray> stack_trace) {
      FixedArray parameters = stack_trace->Parameters(0);
  
      CHECK_EQ(parameters.length(), 2);
      CHECK(parameters.get(0).IsSmi());
      CHECK_EQ(Smi::ToInt(parameters.get(0)), 9999);
    });
  }
  
  TEST(Regress169928) {
    FLAG_allow_natives_syntax = true;
  #ifndef V8_LITE_MODE
    FLAG_opt = false;
  #endif  // V8_LITE_MODE
    CcTest::InitializeVM();
    Isolate* isolate = CcTest::i_isolate();
    LocalContext env;
    Factory* factory = isolate->factory();
    v8::HandleScope scope(CcTest::isolate());
  
    // Some flags turn Scavenge collections into Mark-sweep collections
    // and hence are incompatible with this test case.
    if (FLAG_gc_global || FLAG_stress_compaction ||
        FLAG_stress_incremental_marking)
      return;
  
    // Prepare the environment
    CompileRun("function fastliteralcase(literal, value) {"
               "    literal[0] = value;"
               "    return literal;"
               "}"
               "function get_standard_literal() {"
               "    var literal = [1, 2, 3];"
               "    return literal;"
               "}"
               "obj = fastliteralcase(get_standard_literal(), 1);"
               "obj = fastliteralcase(get_standard_literal(), 1.5);"
               "obj = fastliteralcase(get_standard_literal(), 2);");
  
    // prepare the heap
    v8::Local<v8::String> mote_code_string =
        v8_str("fastliteralcase(mote, 2.5);");
  
    v8::Local<v8::String> array_name = v8_str("mote");
    CHECK(CcTest::global()
              ->Set(env.local(), array_name, v8::Int32::New(CcTest::isolate(), 0))
              .FromJust());
  
    // First make sure we flip spaces
    CcTest::CollectGarbage(NEW_SPACE);
  
    // Allocate the object.
    Handle<FixedArray> array_data =
        factory->NewFixedArray(2, AllocationType::kYoung);
    array_data->set(0, Smi::FromInt(1));
    array_data->set(1, Smi::FromInt(2));
  
    heap::AllocateAllButNBytes(
        CcTest::heap()->new_space(),
        JSArray::kSize + AllocationMemento::kSize + kTaggedSize);
  
    Handle<JSArray> array =
        factory->NewJSArrayWithElements(array_data, PACKED_SMI_ELEMENTS);
  
    CHECK_EQ(Smi::FromInt(2), array->length());
    CHECK(array->HasSmiOrObjectElements());
  
    // We need filler the size of AllocationMemento object, plus an extra
    // fill pointer value.
    HeapObject obj;
    AllocationResult allocation =
        CcTest::heap()->new_space()->AllocateRawUnaligned(
            AllocationMemento::kSize + kTaggedSize);
    CHECK(allocation.To(&obj));
    Address addr_obj = obj.address();
    CcTest::heap()->CreateFillerObjectAt(addr_obj,
                                         AllocationMemento::kSize + kTaggedSize,
                                         ClearRecordedSlots::kNo);
  
    // Give the array a name, making sure not to allocate strings.
    v8::Local<v8::Object> array_obj = v8::Utils::ToLocal(array);
    CHECK(CcTest::global()->Set(env.local(), array_name, array_obj).FromJust());
  
    // This should crash with a protection violation if we are running a build
    // with the bug.
    AlwaysAllocateScope aa_scope(isolate);
    v8::Script::Compile(env.local(), mote_code_string)
        .ToLocalChecked()
        ->Run(env.local())
        .ToLocalChecked();
  }
  
  TEST(LargeObjectSlotRecording) {
    if (!FLAG_incremental_marking) return;
    if (FLAG_never_compact) return;
    ManualGCScope manual_gc_scope;
    FLAG_manual_evacuation_candidates_selection = true;
    CcTest::InitializeVM();
    Isolate* isolate = CcTest::i_isolate();
    Heap* heap = isolate->heap();
    HandleScope scope(isolate);
  
    // Create an object on an evacuation candidate.
    heap::SimulateFullSpace(heap->old_space());
    Handle<FixedArray> lit =
        isolate->factory()->NewFixedArray(4, AllocationType::kOld);
    Page* evac_page = Page::FromHeapObject(*lit);
    heap::ForceEvacuationCandidate(evac_page);
    FixedArray old_location = *lit;
  
    // Allocate a large object.
    int size = Max(1000000, kMaxRegularHeapObjectSize + KB);
    CHECK_LT(kMaxRegularHeapObjectSize, size);
    Handle<FixedArray> lo =
        isolate->factory()->NewFixedArray(size, AllocationType::kOld);
    CHECK(heap->lo_space()->Contains(*lo));
  
    // Start incremental marking to active write barrier.
    heap::SimulateIncrementalMarking(heap, false);
  
    // Create references from the large object to the object on the evacuation
    // candidate.
    const int kStep = size / 10;
    for (int i = 0; i < size; i += kStep) {
      lo->set(i, *lit);
      CHECK(lo->get(i) == old_location);
    }
  
    heap::SimulateIncrementalMarking(heap, true);
  
    // Move the evaucation candidate object.
    CcTest::CollectAllGarbage();
  
    // Verify that the pointers in the large object got updated.
    for (int i = 0; i < size; i += kStep) {
      CHECK_EQ(lo->get(i), *lit);
      CHECK(lo->get(i) != old_location);
    }
  }
  
  class DummyVisitor : public RootVisitor {
   public:
    void VisitRootPointers(Root root, const char* description,
                           FullObjectSlot start, FullObjectSlot end) override {}
  };
  
  
  TEST(DeferredHandles) {
    CcTest::InitializeVM();
    Isolate* isolate = CcTest::i_isolate();
    Heap* heap = isolate->heap();
    v8::HandleScope scope(reinterpret_cast<v8::Isolate*>(isolate));
    HandleScopeData* data = isolate->handle_scope_data();
    Handle<Object> init(ReadOnlyRoots(heap).empty_string(), isolate);
    while (data->next < data->limit) {
      Handle<Object> obj(ReadOnlyRoots(heap).empty_string(), isolate);
    }
    // An entire block of handles has been filled.
    // Next handle would require a new block.
    CHECK(data->next == data->limit);
  
    DeferredHandleScope deferred(isolate);
    DummyVisitor visitor;
    isolate->handle_scope_implementer()->Iterate(&visitor);
    delete deferred.Detach();
  }
  
  
  TEST(IncrementalMarkingStepMakesBigProgressWithLargeObjects) {
    if (!FLAG_incremental_marking) return;
    ManualGCScope manual_gc_scope;
    CcTest::InitializeVM();
    v8::HandleScope scope(CcTest::isolate());
    CompileRun("function f(n) {"
               "    var a = new Array(n);"
               "    for (var i = 0; i < n; i += 100) a[i] = i;"
               "};"
               "f(10 * 1024 * 1024);");
    IncrementalMarking* marking = CcTest::heap()->incremental_marking();
    if (marking->IsStopped()) {
      CcTest::heap()->StartIncrementalMarking(
          i::Heap::kNoGCFlags, i::GarbageCollectionReason::kTesting);
    }
    heap::SimulateIncrementalMarking(CcTest::heap());
    CHECK(marking->IsComplete() ||
          marking->IsReadyToOverApproximateWeakClosure());
  }
  
  
  TEST(DisableInlineAllocation) {
    FLAG_allow_natives_syntax = true;
    CcTest::InitializeVM();
    v8::HandleScope scope(CcTest::isolate());
    CompileRun(
        "function test() {"
        "  var x = [];"
        "  for (var i = 0; i < 10; i++) {"
        "    x[i] = [ {}, [1,2,3], [1,x,3] ];"
        "  }"
        "}"
        "function run() {"
        "  %PrepareFunctionForOptimization(test);"
        "  %OptimizeFunctionOnNextCall(test);"
        "  test();"
        "  %DeoptimizeFunction(test);"
        "}");
  
    // Warm-up with inline allocation enabled.
    CompileRun("test(); test(); run();");
  
    // Run test with inline allocation disabled.
    CcTest::heap()->DisableInlineAllocation();
    CompileRun("run()");
  
    // Run test with inline allocation re-enabled.
    CcTest::heap()->EnableInlineAllocation();
    CompileRun("run()");
  }
  
  
  static int AllocationSitesCount(Heap* heap) {
    int count = 0;
    for (Object site = heap->allocation_sites_list(); site.IsAllocationSite();) {
      AllocationSite cur = AllocationSite::cast(site);
      CHECK(cur.HasWeakNext());
      site = cur.weak_next();
      count++;
    }
    return count;
  }
  
  static int SlimAllocationSiteCount(Heap* heap) {
    int count = 0;
    for (Object weak_list = heap->allocation_sites_list();
         weak_list.IsAllocationSite();) {
      AllocationSite weak_cur = AllocationSite::cast(weak_list);
      for (Object site = weak_cur.nested_site(); site.IsAllocationSite();) {
        AllocationSite cur = AllocationSite::cast(site);
        CHECK(!cur.HasWeakNext());
        site = cur.nested_site();
        count++;
      }
      weak_list = weak_cur.weak_next();
    }
    return count;
  }
  
  TEST(EnsureAllocationSiteDependentCodesProcessed) {
    if (FLAG_always_opt || !FLAG_opt) return;
    FLAG_allow_natives_syntax = true;
    CcTest::InitializeVM();
    Isolate* isolate = CcTest::i_isolate();
    v8::internal::Heap* heap = CcTest::heap();
    GlobalHandles* global_handles = isolate->global_handles();
  
    if (!isolate->use_optimizer()) return;
  
    // The allocation site at the head of the list is ours.
    Handle<AllocationSite> site;
    {
      LocalContext context;
      v8::HandleScope scope(context->GetIsolate());
  
      int count = AllocationSitesCount(heap);
      CompileRun(
          "var bar = function() { return (new Array()); };"
          "%PrepareFunctionForOptimization(bar);"
          "var a = bar();"
          "bar();"
          "bar();");
  
      // One allocation site should have been created.
      int new_count = AllocationSitesCount(heap);
      CHECK_EQ(new_count, (count + 1));
      site = Handle<AllocationSite>::cast(
          global_handles->Create(
              AllocationSite::cast(heap->allocation_sites_list())));
  
      CompileRun("%OptimizeFunctionOnNextCall(bar); bar();");
  
      Handle<JSFunction> bar_handle = Handle<JSFunction>::cast(
          v8::Utils::OpenHandle(*v8::Local<v8::Function>::Cast(
              CcTest::global()
                  ->Get(context.local(), v8_str("bar"))
                  .ToLocalChecked())));
  
      int dependency_group_count = 0;
      DependentCode dependency = site->dependent_code();
      while (dependency != ReadOnlyRoots(heap).empty_weak_fixed_array()) {
        CHECK(dependency.group() ==
                  DependentCode::kAllocationSiteTransitionChangedGroup ||
              dependency.group() ==
                  DependentCode::kAllocationSiteTenuringChangedGroup);
        CHECK_EQ(1, dependency.count());
        CHECK(dependency.object_at(0)->IsWeak());
        Code function_bar =
            Code::cast(dependency.object_at(0)->GetHeapObjectAssumeWeak());
        CHECK_EQ(bar_handle->code(), function_bar);
        dependency = dependency.next_link();
        dependency_group_count++;
      }
      // Expect a dependent code object for transitioning and pretenuring.
      CHECK_EQ(2, dependency_group_count);
    }
  
    // Now make sure that a gc should get rid of the function, even though we
    // still have the allocation site alive.
    for (int i = 0; i < 4; i++) {
      CcTest::CollectAllGarbage();
    }
  
    // The site still exists because of our global handle, but the code is no
    // longer referred to by dependent_code().
    CHECK(site->dependent_code().object_at(0)->IsCleared());
  }
  
  void CheckNumberOfAllocations(Heap* heap, const char* source,
                                int expected_full_alloc,
                                int expected_slim_alloc) {
    int prev_fat_alloc_count = AllocationSitesCount(heap);
    int prev_slim_alloc_count = SlimAllocationSiteCount(heap);
  
    CompileRun(source);
  
    int fat_alloc_sites = AllocationSitesCount(heap) - prev_fat_alloc_count;
    int slim_alloc_sites = SlimAllocationSiteCount(heap) - prev_slim_alloc_count;
  
    CHECK_EQ(expected_full_alloc, fat_alloc_sites);
    CHECK_EQ(expected_slim_alloc, slim_alloc_sites);
  }
  
  TEST(AllocationSiteCreation) {
    FLAG_always_opt = false;
    CcTest::InitializeVM();
    Isolate* isolate = CcTest::i_isolate();
    Heap* heap = isolate->heap();
    HandleScope scope(isolate);
    i::FLAG_allow_natives_syntax = true;
  
    // Array literals.
    CheckNumberOfAllocations(heap,
                             "function f1() {"
                             "  return []; "
                             "};"
                             "%EnsureFeedbackVectorForFunction(f1); f1();",
                             1, 0);
    CheckNumberOfAllocations(heap,
                             "function f2() {"
                             "  return [1, 2];"
                             "};"
                             "%EnsureFeedbackVectorForFunction(f2); f2();",
                             1, 0);
    CheckNumberOfAllocations(heap,
                             "function f3() {"
                             "  return [[1], [2]];"
                             "};"
                             "%EnsureFeedbackVectorForFunction(f3); f3();",
                             1, 2);
    CheckNumberOfAllocations(heap,
                             "function f4() { "
                             "return [0, [1, 1.1, 1.2, "
                             "], 1.5, [2.1, 2.2], 3];"
                             "};"
                             "%EnsureFeedbackVectorForFunction(f4); f4();",
                             1, 2);
  
    // Object literals have lazy AllocationSites
    CheckNumberOfAllocations(heap,
                             "function f5() {"
                             " return {};"
                             "};"
                             "%EnsureFeedbackVectorForFunction(f5); f5();",
                             0, 0);
  
    // No AllocationSites are created for the empty object literal.
    for (int i = 0; i < 5; i++) {
      CheckNumberOfAllocations(heap, "f5(); ", 0, 0);
    }
  
    CheckNumberOfAllocations(heap,
                             "function f6() {"
                             "  return {a:1};"
                             "};"
                             "%EnsureFeedbackVectorForFunction(f6); f6();",
                             0, 0);
  
    CheckNumberOfAllocations(heap, "f6(); ", 1, 0);
  
    CheckNumberOfAllocations(heap,
                             "function f7() {"
                             "  return {a:1, b:2};"
                             "};"
                             "%EnsureFeedbackVectorForFunction(f7); f7(); ",
                             0, 0);
    CheckNumberOfAllocations(heap, "f7(); ", 1, 0);
  
    // No Allocation sites are created for object subliterals
    CheckNumberOfAllocations(heap,
                             "function f8() {"
                             "return {a:{}, b:{ a:2, c:{ d:{f:{}}} } }; "
                             "};"
                             "%EnsureFeedbackVectorForFunction(f8); f8();",
                             0, 0);
    CheckNumberOfAllocations(heap, "f8(); ", 1, 0);
  
    // We currently eagerly create allocation sites if there are sub-arrays.
    // Allocation sites are created only for array subliterals
    CheckNumberOfAllocations(heap,
                             "function f9() {"
                             "return {a:[1, 2, 3], b:{ a:2, c:{ d:{f:[]} } }}; "
                             "};"
                             "%EnsureFeedbackVectorForFunction(f9); f9(); ",
                             1, 2);
  
    // No new AllocationSites created on the second invocation.
    CheckNumberOfAllocations(heap, "f9(); ", 0, 0);
  }
  
  TEST(AllocationSiteCreationForIIFE) {
    // No feedback vectors and hence no allocation sites.
    // TODO(mythria): Once lazy feedback allocation is enabled by default
    // re-evaluate if we need any of these tests.
    if (FLAG_lite_mode || FLAG_lazy_feedback_allocation) return;
    FLAG_always_opt = false;
    CcTest::InitializeVM();
    Isolate* isolate = CcTest::i_isolate();
    Heap* heap = isolate->heap();
    HandleScope scope(isolate);
    i::FLAG_enable_one_shot_optimization = true;
  
    // No allocation sites within IIFE/top-level
    CheckNumberOfAllocations(heap,
                             R"(
                              (function f4() {
                                return [ 0, [ 1, 1.1, 1.2,], 1.5, [2.1, 2.2], 3 ];
                              })();
                              )",
                             0, 0);
  
    CheckNumberOfAllocations(heap,
                             R"(
                              l = [ 1, 2, 3, 4];
                              )",
                             0, 0);
  
    CheckNumberOfAllocations(heap,
                             R"(
                              a = [];
                              )",
                             0, 0);
  
    CheckNumberOfAllocations(heap,
                             R"(
                              (function f4() {
                                return [];
                              })();
                              )",
                             0, 0);
  
    // No allocation sites for literals in an iife/top level code even if it has
    // array subliterals
    CheckNumberOfAllocations(heap,
                             R"(
                              (function f10() {
                                return {a: [1], b: [2]};
                              })();
                              )",
                             0, 0);
  
    CheckNumberOfAllocations(heap,
                             R"(
                              l = {
                                a: 1,
                                b: {
                                  c: [5],
                                }
                              };
                              )",
                             0, 0);
  
    // Eagerly create allocation sites for literals within a loop of iife or
    // top-level code
    CheckNumberOfAllocations(heap,
                             R"(
                              (function f11() {
                                while(true) {
                                  return {a: [1], b: [2]};
                                }
                              })();
                              )",
                             1, 2);
  
    CheckNumberOfAllocations(heap,
                             R"(
                              for (i = 0; i < 1; ++i) {
                                l = {
                                  a: 1,
                                  b: {
                                    c: [5],
                                  }
                                };
                              }
                              )",
                             1, 1);
  }
  
  TEST(CellsInOptimizedCodeAreWeak) {
    if (FLAG_always_opt || !FLAG_opt) return;
    FLAG_allow_natives_syntax = true;
    CcTest::InitializeVM();
    Isolate* isolate = CcTest::i_isolate();
    v8::internal::Heap* heap = CcTest::heap();
  
    if (!isolate->use_optimizer()) return;
    HandleScope outer_scope(heap->isolate());
    Handle<Code> code;
    {
      LocalContext context;
      HandleScope scope(heap->isolate());
  
      CompileRun(
          "bar = (function() {"
          "  function bar() {"
          "    return foo(1);"
          "  };"
          "  %PrepareFunctionForOptimization(bar);"
          "  var foo = function(x) { with (x) { return 1 + x; } };"
          "  %NeverOptimizeFunction(foo);"
          "  bar(foo);"
          "  bar(foo);"
          "  bar(foo);"
          "  %OptimizeFunctionOnNextCall(bar);"
          "  bar(foo);"
          "  return bar;})();");
  
      Handle<JSFunction> bar = Handle<JSFunction>::cast(v8::Utils::OpenHandle(
          *v8::Local<v8::Function>::Cast(CcTest::global()
                                             ->Get(context.local(), v8_str("bar"))
                                             .ToLocalChecked())));
      code = scope.CloseAndEscape(Handle<Code>(bar->code(), isolate));
    }
  
    // Now make sure that a gc should get rid of the function
    for (int i = 0; i < 4; i++) {
      CcTest::CollectAllGarbage();
    }
  
    CHECK(code->marked_for_deoptimization());
    CHECK(code->embedded_objects_cleared());
  }
  
  
  TEST(ObjectsInOptimizedCodeAreWeak) {
    if (FLAG_always_opt || !FLAG_opt) return;
    FLAG_allow_natives_syntax = true;
    CcTest::InitializeVM();
    Isolate* isolate = CcTest::i_isolate();
    v8::internal::Heap* heap = CcTest::heap();
  
    if (!isolate->use_optimizer()) return;
    HandleScope outer_scope(heap->isolate());
    Handle<Code> code;
    {
      LocalContext context;
      HandleScope scope(heap->isolate());
  
      CompileRun(
          "function bar() {"
          "  return foo(1);"
          "};"
          "%PrepareFunctionForOptimization(bar);"
          "function foo(x) { with (x) { return 1 + x; } };"
          "%NeverOptimizeFunction(foo);"
          "bar();"
          "bar();"
          "bar();"
          "%OptimizeFunctionOnNextCall(bar);"
          "bar();");
  
      Handle<JSFunction> bar = Handle<JSFunction>::cast(v8::Utils::OpenHandle(
          *v8::Local<v8::Function>::Cast(CcTest::global()
                                             ->Get(context.local(), v8_str("bar"))
                                             .ToLocalChecked())));
      code = scope.CloseAndEscape(Handle<Code>(bar->code(), isolate));
    }
  
    // Now make sure that a gc should get rid of the function
    for (int i = 0; i < 4; i++) {
      CcTest::CollectAllGarbage();
    }
  
    CHECK(code->marked_for_deoptimization());
    CHECK(code->embedded_objects_cleared());
  }
  
  TEST(NewSpaceObjectsInOptimizedCode) {
    if (FLAG_always_opt || !FLAG_opt) return;
    FLAG_allow_natives_syntax = true;
    CcTest::InitializeVM();
    Isolate* isolate = CcTest::i_isolate();
  
    if (!isolate->use_optimizer()) return;
    HandleScope outer_scope(isolate);
    Handle<Code> code;
    {
      LocalContext context;
      HandleScope scope(isolate);
  
      CompileRun(
          "var foo;"
          "var bar;"
          "(function() {"
          "  function foo_func(x) { with (x) { return 1 + x; } };"
          "  %NeverOptimizeFunction(foo_func);"
          "  function bar_func() {"
          "    return foo(1);"
          "  };"
          "  %PrepareFunctionForOptimization(bar_func);"
          "  bar = bar_func;"
          "  foo = foo_func;"
          "  bar_func();"
          "  bar_func();"
          "  bar_func();"
          "  %OptimizeFunctionOnNextCall(bar_func);"
          "  bar_func();"
          "})();");
  
      Handle<JSFunction> bar = Handle<JSFunction>::cast(v8::Utils::OpenHandle(
          *v8::Local<v8::Function>::Cast(CcTest::global()
                                             ->Get(context.local(), v8_str("bar"))
                                             .ToLocalChecked())));
  
      Handle<JSFunction> foo = Handle<JSFunction>::cast(v8::Utils::OpenHandle(
          *v8::Local<v8::Function>::Cast(CcTest::global()
                                             ->Get(context.local(), v8_str("foo"))
                                             .ToLocalChecked())));
  
      CHECK(Heap::InYoungGeneration(*foo));
      CcTest::CollectGarbage(NEW_SPACE);
      CcTest::CollectGarbage(NEW_SPACE);
      CHECK(!Heap::InYoungGeneration(*foo));
  #ifdef VERIFY_HEAP
      CcTest::heap()->Verify();
  #endif
      CHECK(!bar->code().marked_for_deoptimization());
      code = scope.CloseAndEscape(Handle<Code>(bar->code(), isolate));
    }
  
    // Now make sure that a gc should get rid of the function
    for (int i = 0; i < 4; i++) {
      CcTest::CollectAllGarbage();
    }
  
    CHECK(code->marked_for_deoptimization());
    CHECK(code->embedded_objects_cleared());
  }
  
  TEST(ObjectsInEagerlyDeoptimizedCodeAreWeak) {
    if (FLAG_always_opt || !FLAG_opt) return;
    FLAG_allow_natives_syntax = true;
    CcTest::InitializeVM();
    Isolate* isolate = CcTest::i_isolate();
    v8::internal::Heap* heap = CcTest::heap();
  
    if (!isolate->use_optimizer()) return;
    HandleScope outer_scope(heap->isolate());
    Handle<Code> code;
    {
      LocalContext context;
      HandleScope scope(heap->isolate());
  
      CompileRun(
          "function bar() {"
          "  return foo(1);"
          "};"
          "function foo(x) { with (x) { return 1 + x; } };"
          "%NeverOptimizeFunction(foo);"
          "%PrepareFunctionForOptimization(bar);"
          "bar();"
          "bar();"
          "bar();"
          "%OptimizeFunctionOnNextCall(bar);"
          "bar();"
          "%DeoptimizeFunction(bar);");
  
      Handle<JSFunction> bar = Handle<JSFunction>::cast(v8::Utils::OpenHandle(
          *v8::Local<v8::Function>::Cast(CcTest::global()
                                             ->Get(context.local(), v8_str("bar"))
                                             .ToLocalChecked())));
      code = scope.CloseAndEscape(Handle<Code>(bar->code(), isolate));
    }
  
    CHECK(code->marked_for_deoptimization());
  
    // Now make sure that a gc should get rid of the function
    for (int i = 0; i < 4; i++) {
      CcTest::CollectAllGarbage();
    }
  
    CHECK(code->marked_for_deoptimization());
    CHECK(code->embedded_objects_cleared());
  }
  
  static Handle<JSFunction> OptimizeDummyFunction(v8::Isolate* isolate,
                                                  const char* name) {
    EmbeddedVector<char, 256> source;
    SNPrintF(source,
             "function %s() { return 0; }"
             "%%PrepareFunctionForOptimization(%s);"
             "%s(); %s();"
             "%%OptimizeFunctionOnNextCall(%s);"
             "%s();",
             name, name, name, name, name, name);
    CompileRun(source.begin());
    i::Handle<JSFunction> fun = Handle<JSFunction>::cast(
        v8::Utils::OpenHandle(*v8::Local<v8::Function>::Cast(
            CcTest::global()
                ->Get(isolate->GetCurrentContext(), v8_str(name))
                .ToLocalChecked())));
    return fun;
  }
  
  static int GetCodeChainLength(Code code) {
    int result = 0;
    while (code.next_code_link().IsCode()) {
      result++;
      code = Code::cast(code.next_code_link());
    }
    return result;
  }
  
  
  TEST(NextCodeLinkIsWeak) {
    FLAG_always_opt = false;
    FLAG_allow_natives_syntax = true;
    CcTest::InitializeVM();
    Isolate* isolate = CcTest::i_isolate();
    v8::internal::Heap* heap = CcTest::heap();
  
    if (!isolate->use_optimizer()) return;
    HandleScope outer_scope(heap->isolate());
    Handle<Code> code;
    CcTest::CollectAllAvailableGarbage();
    int code_chain_length_before, code_chain_length_after;
    {
      HandleScope scope(heap->isolate());
      Handle<JSFunction> mortal =
          OptimizeDummyFunction(CcTest::isolate(), "mortal");
      Handle<JSFunction> immortal =
          OptimizeDummyFunction(CcTest::isolate(), "immortal");
      CHECK_EQ(immortal->code().next_code_link(), mortal->code());
      code_chain_length_before = GetCodeChainLength(immortal->code());
      // Keep the immortal code and let the mortal code die.
      code = scope.CloseAndEscape(Handle<Code>(immortal->code(), isolate));
      CompileRun("mortal = null; immortal = null;");
    }
    CcTest::CollectAllAvailableGarbage();
    // Now mortal code should be dead.
    code_chain_length_after = GetCodeChainLength(*code);
    CHECK_EQ(code_chain_length_before - 1, code_chain_length_after);
  }
  
  TEST(NextCodeLinkInCodeDataContainerIsCleared) {
    FLAG_always_opt = false;
    FLAG_allow_natives_syntax = true;
    CcTest::InitializeVM();
    Isolate* isolate = CcTest::i_isolate();
    v8::internal::Heap* heap = CcTest::heap();
  
    if (!isolate->use_optimizer()) return;
    HandleScope outer_scope(heap->isolate());
    Handle<CodeDataContainer> code_data_container;
    {
      HandleScope scope(heap->isolate());
      Handle<JSFunction> mortal1 =
          OptimizeDummyFunction(CcTest::isolate(), "mortal1");
      Handle<JSFunction> mortal2 =
          OptimizeDummyFunction(CcTest::isolate(), "mortal2");
      CHECK_EQ(mortal2->code().next_code_link(), mortal1->code());
      code_data_container = scope.CloseAndEscape(Handle<CodeDataContainer>(
          mortal2->code().code_data_container(), isolate));
      CompileRun("mortal1 = null; mortal2 = null;");
    }
    CcTest::CollectAllAvailableGarbage();
    CHECK(code_data_container->next_code_link().IsUndefined(isolate));
  }
  
  static Handle<Code> DummyOptimizedCode(Isolate* isolate) {
    i::byte buffer[i::Assembler::kMinimalBufferSize];
    MacroAssembler masm(isolate, v8::internal::CodeObjectRequired::kYes,
                        ExternalAssemblerBuffer(buffer, sizeof(buffer)));
    CodeDesc desc;
    masm.Push(isolate->factory()->undefined_value());
    masm.Push(isolate->factory()->undefined_value());
    masm.Drop(2);
    masm.GetCode(isolate, &desc);
    Handle<Code> code =
        Factory::CodeBuilder(isolate, desc, Code::OPTIMIZED_FUNCTION)
            .set_self_reference(masm.CodeObject())
            .Build();
    CHECK(code->IsCode());
    return code;
  }
  
  
  TEST(NextCodeLinkIsWeak2) {
    FLAG_allow_natives_syntax = true;
    CcTest::InitializeVM();
    Isolate* isolate = CcTest::i_isolate();
    v8::internal::Heap* heap = CcTest::heap();
  
    if (!isolate->use_optimizer()) return;
    HandleScope outer_scope(heap->isolate());
    CcTest::CollectAllAvailableGarbage();
    Handle<Context> context(Context::cast(heap->native_contexts_list()), isolate);
    Handle<Code> new_head;
    Handle<Object> old_head(context->get(Context::OPTIMIZED_CODE_LIST), isolate);
    {
      HandleScope scope(heap->isolate());
      Handle<Code> immortal = DummyOptimizedCode(isolate);
      Handle<Code> mortal = DummyOptimizedCode(isolate);
      mortal->set_next_code_link(*old_head);
      immortal->set_next_code_link(*mortal);
      context->set(Context::OPTIMIZED_CODE_LIST, *immortal);
      new_head = scope.CloseAndEscape(immortal);
    }
    CcTest::CollectAllAvailableGarbage();
    // Now mortal code should be dead.
    CHECK_EQ(*old_head, new_head->next_code_link());
  }
  
  
  static bool weak_ic_cleared = false;
  
  static void ClearWeakIC(
      const v8::WeakCallbackInfo<v8::Persistent<v8::Object>>& data) {
    printf("clear weak is called\n");
    weak_ic_cleared = true;
    data.GetParameter()->Reset();
  }
  
  
  TEST(WeakFunctionInConstructor) {
    if (FLAG_always_opt) return;
    FLAG_stress_compaction = false;
    FLAG_stress_incremental_marking = false;
    FLAG_allow_natives_syntax = true;
    CcTest::InitializeVM();
    v8::Isolate* isolate = CcTest::isolate();
    LocalContext env;
    v8::HandleScope scope(isolate);
    CompileRun(
        "function createObj(obj) {"
        "  return new obj();"
        "}");
    i::Handle<JSFunction> createObj = Handle<JSFunction>::cast(
        v8::Utils::OpenHandle(*v8::Local<v8::Function>::Cast(
            CcTest::global()
                ->Get(env.local(), v8_str("createObj"))
                .ToLocalChecked())));
  
    v8::Persistent<v8::Object> garbage;
    {
      v8::HandleScope scope(isolate);
      const char* source =
          " (function() {"
          "   function hat() { this.x = 5; }"
          "   %EnsureFeedbackVectorForFunction(hat);"
          "   %EnsureFeedbackVectorForFunction(createObj);"
          "   createObj(hat);"
          "   createObj(hat);"
          "   return hat;"
          " })();";
      garbage.Reset(isolate, CompileRun(env.local(), source)
                                 .ToLocalChecked()
                                 ->ToObject(env.local())
                                 .ToLocalChecked());
    }
    weak_ic_cleared = false;
    garbage.SetWeak(&garbage, &ClearWeakIC, v8::WeakCallbackType::kParameter);
    CcTest::CollectAllGarbage();
    CHECK(weak_ic_cleared);
  
    // We've determined the constructor in createObj has had it's weak cell
    // cleared. Now, verify that one additional call with a new function
    // allows monomorphicity.
    Handle<FeedbackVector> feedback_vector =
        Handle<FeedbackVector>(createObj->feedback_vector(), CcTest::i_isolate());
    for (int i = 0; i < 20; i++) {
      MaybeObject slot_value = feedback_vector->Get(FeedbackSlot(0));
      CHECK(slot_value->IsWeakOrCleared());
      if (slot_value->IsCleared()) break;
      CcTest::CollectAllGarbage();
    }
  
    MaybeObject slot_value = feedback_vector->Get(FeedbackSlot(0));
    CHECK(slot_value->IsCleared());
    CompileRun(
        "function coat() { this.x = 6; }"
        "createObj(coat);");
    slot_value = feedback_vector->Get(FeedbackSlot(0));
    CHECK(slot_value->IsWeak());
  }
  
  
  // Checks that the value returned by execution of the source is weak.
  void CheckWeakness(const char* source) {
    FLAG_stress_compaction = false;
    FLAG_stress_incremental_marking = false;
    FLAG_allow_natives_syntax = true;
    CcTest::InitializeVM();
    v8::Isolate* isolate = CcTest::isolate();
    LocalContext env;
    v8::HandleScope scope(isolate);
    v8::Persistent<v8::Object> garbage;
    {
      v8::HandleScope scope(isolate);
      garbage.Reset(isolate, CompileRun(env.local(), source)
                                 .ToLocalChecked()
                                 ->ToObject(env.local())
                                 .ToLocalChecked());
    }
    weak_ic_cleared = false;
    garbage.SetWeak(&garbage, &ClearWeakIC, v8::WeakCallbackType::kParameter);
    CcTest::CollectAllGarbage();
    CHECK(weak_ic_cleared);
  }
  
  
  // Each of the following "weak IC" tests creates an IC that embeds a map with
  // the prototype pointing to _proto_ and checks that the _proto_ dies on GC.
  TEST(WeakMapInMonomorphicLoadIC) {
    CheckWeakness(
        "function loadIC(obj) {"
        "  return obj.name;"
        "}"
        "%EnsureFeedbackVectorForFunction(loadIC);"
        " (function() {"
        "   var proto = {'name' : 'weak'};"
        "   var obj = Object.create(proto);"
        "   loadIC(obj);"
        "   loadIC(obj);"
        "   loadIC(obj);"
        "   return proto;"
        " })();");
  }
  
  
  TEST(WeakMapInPolymorphicLoadIC) {
    CheckWeakness(
        "function loadIC(obj) {"
        "  return obj.name;"
        "}"
        "%EnsureFeedbackVectorForFunction(loadIC);"
        " (function() {"
        "   var proto = {'name' : 'weak'};"
        "   var obj = Object.create(proto);"
        "   loadIC(obj);"
        "   loadIC(obj);"
        "   loadIC(obj);"
        "   var poly = Object.create(proto);"
        "   poly.x = true;"
        "   loadIC(poly);"
        "   return proto;"
        " })();");
  }
  
  
  TEST(WeakMapInMonomorphicKeyedLoadIC) {
    CheckWeakness(
        "function keyedLoadIC(obj, field) {"
        "  return obj[field];"
        "}"
        "%EnsureFeedbackVectorForFunction(keyedLoadIC);"
        " (function() {"
        "   var proto = {'name' : 'weak'};"
        "   var obj = Object.create(proto);"
        "   keyedLoadIC(obj, 'name');"
        "   keyedLoadIC(obj, 'name');"
        "   keyedLoadIC(obj, 'name');"
        "   return proto;"
        " })();");
  }
  
  
  TEST(WeakMapInPolymorphicKeyedLoadIC) {
    CheckWeakness(
        "function keyedLoadIC(obj, field) {"
        "  return obj[field];"
        "}"
        "%EnsureFeedbackVectorForFunction(keyedLoadIC);"
        " (function() {"
        "   var proto = {'name' : 'weak'};"
        "   var obj = Object.create(proto);"
        "   keyedLoadIC(obj, 'name');"
        "   keyedLoadIC(obj, 'name');"
        "   keyedLoadIC(obj, 'name');"
        "   var poly = Object.create(proto);"
        "   poly.x = true;"
        "   keyedLoadIC(poly, 'name');"
        "   return proto;"
        " })();");
  }
  
  
  TEST(WeakMapInMonomorphicStoreIC) {
    CheckWeakness(
        "function storeIC(obj, value) {"
        "  obj.name = value;"
        "}"
        "%EnsureFeedbackVectorForFunction(storeIC);"
        " (function() {"
        "   var proto = {'name' : 'weak'};"
        "   var obj = Object.create(proto);"
        "   storeIC(obj, 'x');"
        "   storeIC(obj, 'x');"
        "   storeIC(obj, 'x');"
        "   return proto;"
        " })();");
  }
  
  
  TEST(WeakMapInPolymorphicStoreIC) {
    CheckWeakness(
        "function storeIC(obj, value) {"
        "  obj.name = value;"
        "}"
        "%EnsureFeedbackVectorForFunction(storeIC);"
        " (function() {"
        "   var proto = {'name' : 'weak'};"
        "   var obj = Object.create(proto);"
        "   storeIC(obj, 'x');"
        "   storeIC(obj, 'x');"
        "   storeIC(obj, 'x');"
        "   var poly = Object.create(proto);"
        "   poly.x = true;"
        "   storeIC(poly, 'x');"
        "   return proto;"
        " })();");
  }
  
  
  TEST(WeakMapInMonomorphicKeyedStoreIC) {
    CheckWeakness(
        "function keyedStoreIC(obj, field, value) {"
        "  obj[field] = value;"
        "}"
        "%EnsureFeedbackVectorForFunction(keyedStoreIC);"
        " (function() {"
        "   var proto = {'name' : 'weak'};"
        "   var obj = Object.create(proto);"
        "   keyedStoreIC(obj, 'x');"
        "   keyedStoreIC(obj, 'x');"
        "   keyedStoreIC(obj, 'x');"
        "   return proto;"
        " })();");
  }
  
  
  TEST(WeakMapInPolymorphicKeyedStoreIC) {
    CheckWeakness(
        "function keyedStoreIC(obj, field, value) {"
        "  obj[field] = value;"
        "}"
        "%EnsureFeedbackVectorForFunction(keyedStoreIC);"
        " (function() {"
        "   var proto = {'name' : 'weak'};"
        "   var obj = Object.create(proto);"
        "   keyedStoreIC(obj, 'x');"
        "   keyedStoreIC(obj, 'x');"
        "   keyedStoreIC(obj, 'x');"
        "   var poly = Object.create(proto);"
        "   poly.x = true;"
        "   keyedStoreIC(poly, 'x');"
        "   return proto;"
        " })();");
  }
  
  
  TEST(WeakMapInMonomorphicCompareNilIC) {
    FLAG_allow_natives_syntax = true;
    CheckWeakness(
        "function compareNilIC(obj) {"
        "  return obj == null;"
        "}"
        "%EnsureFeedbackVectorForFunction(compareNilIC);"
        " (function() {"
        "   var proto = {'name' : 'weak'};"
        "   var obj = Object.create(proto);"
        "   compareNilIC(obj);"
        "   compareNilIC(obj);"
        "   compareNilIC(obj);"
        "   return proto;"
        " })();");
  }
  
  
  Handle<JSFunction> GetFunctionByName(Isolate* isolate, const char* name) {
    Handle<String> str = isolate->factory()->InternalizeUtf8String(name);
    Handle<Object> obj =
        Object::GetProperty(isolate, isolate->global_object(), str)
            .ToHandleChecked();
    return Handle<JSFunction>::cast(obj);
  }
  
  void CheckIC(Handle<JSFunction> function, int slot_index,
               InlineCacheState state) {
    FeedbackVector vector = function->feedback_vector();
    FeedbackSlot slot(slot_index);
    FeedbackNexus nexus(vector, slot);
    CHECK_EQ(nexus.ic_state(), state);
  }
  
  TEST(MonomorphicStaysMonomorphicAfterGC) {
    if (!FLAG_use_ic) return;
    if (FLAG_always_opt) return;
    ManualGCScope manual_gc_scope;
    CcTest::InitializeVM();
    Isolate* isolate = CcTest::i_isolate();
    v8::HandleScope scope(CcTest::isolate());
    FLAG_allow_natives_syntax = true;
    CompileRun(
        "function loadIC(obj) {"
        "  return obj.name;"
        "}"
        "%EnsureFeedbackVectorForFunction(loadIC);"
        "function testIC() {"
        "  var proto = {'name' : 'weak'};"
        "  var obj = Object.create(proto);"
        "  loadIC(obj);"
        "  loadIC(obj);"
        "  loadIC(obj);"
        "  return proto;"
        "};");
    Handle<JSFunction> loadIC = GetFunctionByName(isolate, "loadIC");
    {
      v8::HandleScope scope(CcTest::isolate());
      CompileRun("(testIC())");
    }
    CcTest::CollectAllGarbage();
    CheckIC(loadIC, 0, MONOMORPHIC);
    {
      v8::HandleScope scope(CcTest::isolate());
      CompileRun("(testIC())");
    }
    CheckIC(loadIC, 0, MONOMORPHIC);
  }
  
  
  TEST(PolymorphicStaysPolymorphicAfterGC) {
    if (!FLAG_use_ic) return;
    if (FLAG_always_opt) return;
    ManualGCScope manual_gc_scope;
    CcTest::InitializeVM();
    Isolate* isolate = CcTest::i_isolate();
    v8::HandleScope scope(CcTest::isolate());
    FLAG_allow_natives_syntax = true;
    CompileRun(
        "function loadIC(obj) {"
        "  return obj.name;"
        "}"
        "%EnsureFeedbackVectorForFunction(loadIC);"
        "function testIC() {"
        "  var proto = {'name' : 'weak'};"
        "  var obj = Object.create(proto);"
        "  loadIC(obj);"
        "  loadIC(obj);"
        "  loadIC(obj);"
        "  var poly = Object.create(proto);"
        "  poly.x = true;"
        "  loadIC(poly);"
        "  return proto;"
        "};");
    Handle<JSFunction> loadIC = GetFunctionByName(isolate, "loadIC");
    {
      v8::HandleScope scope(CcTest::isolate());
      CompileRun("(testIC())");
    }
    CcTest::CollectAllGarbage();
    CheckIC(loadIC, 0, POLYMORPHIC);
    {
      v8::HandleScope scope(CcTest::isolate());
      CompileRun("(testIC())");
    }
    CheckIC(loadIC, 0, POLYMORPHIC);
  }
  
  #ifdef DEBUG
  TEST(AddInstructionChangesNewSpacePromotion) {
    FLAG_allow_natives_syntax = true;
    FLAG_expose_gc = true;
    FLAG_stress_compaction = true;
    FLAG_gc_interval = 1000;
    CcTest::InitializeVM();
    if (!FLAG_allocation_site_pretenuring) return;
    v8::HandleScope scope(CcTest::isolate());
    Isolate* isolate = CcTest::i_isolate();
    Heap* heap = isolate->heap();
    LocalContext env;
    CompileRun(
        "function add(a, b) {"
        "  return a + b;"
        "}"
        "add(1, 2);"
        "add(\"a\", \"b\");"
        "var oldSpaceObject;"
        "gc();"
        "function crash(x) {"
        "  var object = {a: null, b: null};"
        "  var result = add(1.5, x | 0);"
        "  object.a = result;"
        "  oldSpaceObject = object;"
        "  return object;"
        "}"
        "%PrepareFunctionForOptimization(crash);"
        "crash(1);"
        "crash(1);"
        "%OptimizeFunctionOnNextCall(crash);"
        "crash(1);");
  
    v8::Local<v8::Object> global = CcTest::global();
    v8::Local<v8::Function> g = v8::Local<v8::Function>::Cast(
        global->Get(env.local(), v8_str("crash")).ToLocalChecked());
    v8::Local<v8::Value> args1[] = {v8_num(1)};
    heap->DisableInlineAllocation();
    heap->set_allocation_timeout(1);
    g->Call(env.local(), global, 1, args1).ToLocalChecked();
    CcTest::CollectAllGarbage();
  }
  
  
  void OnFatalErrorExpectOOM(const char* location, const char* message) {
    // Exit with 0 if the location matches our expectation.
    exit(strcmp(location, "CALL_AND_RETRY_LAST"));
  }
  
  
  TEST(CEntryStubOOM) {
    FLAG_allow_natives_syntax = true;
    CcTest::InitializeVM();
    v8::HandleScope scope(CcTest::isolate());
    CcTest::isolate()->SetFatalErrorHandler(OnFatalErrorExpectOOM);
  
    v8::Local<v8::Value> result = CompileRun(
        "%SetAllocationTimeout(1, 1);"
        "var a = [];"
        "a.__proto__ = [];"
        "a.unshift(1)");
  
    CHECK(result->IsNumber());
  }
  
  #endif  // DEBUG
  
  
  static void InterruptCallback357137(v8::Isolate* isolate, void* data) { }
  
  
  static void RequestInterrupt(const v8::FunctionCallbackInfo<v8::Value>& args) {
    CcTest::isolate()->RequestInterrupt(&InterruptCallback357137, nullptr);
  }
  
  HEAP_TEST(Regress538257) {
    ManualGCScope manual_gc_scope;
    FLAG_manual_evacuation_candidates_selection = true;
    v8::Isolate::CreateParams create_params;
    // Set heap limits.
    create_params.constraints.set_max_young_generation_size_in_bytes(3 * MB);
  #ifdef DEBUG
    create_params.constraints.set_max_old_generation_size_in_bytes(20 * MB);
  #else
    create_params.constraints.set_max_old_generation_size_in_bytes(6 * MB);
  #endif
    create_params.array_buffer_allocator = CcTest::array_buffer_allocator();
    v8::Isolate* isolate = v8::Isolate::New(create_params);
    isolate->Enter();
    {
      i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
      Heap* heap = i_isolate->heap();
      HandleScope handle_scope(i_isolate);
      PagedSpace* old_space = heap->old_space();
      const int kMaxObjects = 10000;
      const int kFixedArrayLen = 512;
      Handle<FixedArray> objects[kMaxObjects];
      for (int i = 0; (i < kMaxObjects) &&
                      heap->CanExpandOldGeneration(old_space->AreaSize());
           i++) {
        objects[i] = i_isolate->factory()->NewFixedArray(kFixedArrayLen,
                                                         AllocationType::kOld);
        heap::ForceEvacuationCandidate(Page::FromHeapObject(*objects[i]));
      }
      heap::SimulateFullSpace(old_space);
      CcTest::CollectAllGarbage();
      // If we get this far, we've successfully aborted compaction. Any further
      // allocations might trigger OOM.
    }
    isolate->Exit();
    isolate->Dispose();
  }
  
  
  TEST(Regress357137) {
    CcTest::InitializeVM();
    v8::Isolate* isolate = CcTest::isolate();
    v8::HandleScope hscope(isolate);
    v8::Local<v8::ObjectTemplate> global = v8::ObjectTemplate::New(isolate);
    global->Set(
        v8::String::NewFromUtf8(isolate, "interrupt", v8::NewStringType::kNormal)
            .ToLocalChecked(),
        v8::FunctionTemplate::New(isolate, RequestInterrupt));
    v8::Local<v8::Context> context = v8::Context::New(isolate, nullptr, global);
    CHECK(!context.IsEmpty());
    v8::Context::Scope cscope(context);
  
    v8::Local<v8::Value> result = CompileRun(
        "var locals = '';"
        "for (var i = 0; i < 512; i++) locals += 'var v' + i + '= 42;';"
        "eval('function f() {' + locals + 'return function() { return v0; }; }');"
        "interrupt();"  // This triggers a fake stack overflow in f.
        "f()()");
    CHECK_EQ(42.0, result->ToNumber(context).ToLocalChecked()->Value());
  }
  
  
  TEST(Regress507979) {
    const int kFixedArrayLen = 10;
    CcTest::InitializeVM();
    Isolate* isolate = CcTest::i_isolate();
    HandleScope handle_scope(isolate);
  
    Handle<FixedArray> o1 = isolate->factory()->NewFixedArray(kFixedArrayLen);
    Handle<FixedArray> o2 = isolate->factory()->NewFixedArray(kFixedArrayLen);
    CHECK(Heap::InYoungGeneration(*o1));
    CHECK(Heap::InYoungGeneration(*o2));
  
    HeapObjectIterator it(isolate->heap(),
                          i::HeapObjectIterator::kFilterUnreachable);
  
    // Replace parts of an object placed before a live object with a filler. This
    // way the filler object shares the mark bits with the following live object.
    o1->Shrink(isolate, kFixedArrayLen - 1);
  
    for (HeapObject obj = it.Next(); !obj.is_null(); obj = it.Next()) {
      // Let's not optimize the loop away.
      CHECK_NE(obj.address(), kNullAddress);
    }
  }
  
  TEST(Regress388880) {
    if (!FLAG_incremental_marking) return;
    FLAG_stress_incremental_marking = false;
    FLAG_expose_gc = true;
    CcTest::InitializeVM();
    v8::HandleScope scope(CcTest::isolate());
    Isolate* isolate = CcTest::i_isolate();
    Factory* factory = isolate->factory();
    Heap* heap = isolate->heap();
  
    Handle<Map> map1 = Map::Create(isolate, 1);
    Handle<String> name = factory->NewStringFromStaticChars("foo");
    name = factory->InternalizeString(name);
    Handle<Map> map2 =
        Map::CopyWithField(isolate, map1, name, FieldType::Any(isolate), NONE,
                           PropertyConstness::kMutable, Representation::Tagged(),
                           OMIT_TRANSITION)
            .ToHandleChecked();
  
    size_t desired_offset = Page::kPageSize - map1->instance_size();
  
    // Allocate padding objects in old pointer space so, that object allocated
    // afterwards would end at the end of the page.
    heap::SimulateFullSpace(heap->old_space());
    size_t padding_size =
        desired_offset - MemoryChunkLayout::ObjectStartOffsetInDataPage();
    heap::CreatePadding(heap, static_cast<int>(padding_size),
                        AllocationType::kOld);
  
    Handle<JSObject> o = factory->NewJSObjectFromMap(map1, AllocationType::kOld);
    o->set_raw_properties_or_hash(*factory->empty_fixed_array());
  
    // Ensure that the object allocated where we need it.
    Page* page = Page::FromHeapObject(*o);
    CHECK_EQ(desired_offset, page->Offset(o->address()));
  
    // Now we have an object right at the end of the page.
  
    // Enable incremental marking to trigger actions in Heap::AdjustLiveBytes()
    // that would cause crash.
    IncrementalMarking* marking = CcTest::heap()->incremental_marking();
    marking->Stop();
    CcTest::heap()->StartIncrementalMarking(i::Heap::kNoGCFlags,
                                            i::GarbageCollectionReason::kTesting);
    CHECK(marking->IsMarking());
  
    // Now everything is set up for crashing in JSObject::MigrateFastToFast()
    // when it calls heap->AdjustLiveBytes(...).
    JSObject::MigrateToMap(isolate, o, map2);
  }
  
  
  TEST(Regress3631) {
    if (!FLAG_incremental_marking) return;
    FLAG_expose_gc = true;
    CcTest::InitializeVM();
    v8::HandleScope scope(CcTest::isolate());
    Isolate* isolate = CcTest::i_isolate();
    Heap* heap = isolate->heap();
    IncrementalMarking* marking = CcTest::heap()->incremental_marking();
    v8::Local<v8::Value> result = CompileRun(
        "var weak_map = new WeakMap();"
        "var future_keys = [];"
        "for (var i = 0; i < 50; i++) {"
        "  var key = {'k' : i + 0.1};"
        "  weak_map.set(key, 1);"
        "  future_keys.push({'x' : i + 0.2});"
        "}"
        "weak_map");
    if (marking->IsStopped()) {
      CcTest::heap()->StartIncrementalMarking(
          i::Heap::kNoGCFlags, i::GarbageCollectionReason::kTesting);
    }
    // Incrementally mark the backing store.
    Handle<JSReceiver> obj =
        v8::Utils::OpenHandle(*v8::Local<v8::Object>::Cast(result));
    Handle<JSWeakCollection> weak_map(JSWeakCollection::cast(*obj), isolate);
    SimulateIncrementalMarking(heap);
    // Stash the backing store in a handle.
    Handle<Object> save(weak_map->table(), isolate);
    // The following line will update the backing store.
    CompileRun(
        "for (var i = 0; i < 50; i++) {"
        "  weak_map.set(future_keys[i], i);"
        "}");
    heap->incremental_marking()->set_should_hurry(true);
    CcTest::CollectGarbage(OLD_SPACE);
  }
  
  
  TEST(Regress442710) {
    CcTest::InitializeVM();
    Isolate* isolate = CcTest::i_isolate();
    Factory* factory = isolate->factory();
  
    HandleScope sc(isolate);
    Handle<JSGlobalObject> global(CcTest::i_isolate()->context().global_object(),
                                  isolate);
    Handle<JSArray> array = factory->NewJSArray(2);
  
    Handle<String> name = factory->InternalizeUtf8String("testArray");
    Object::SetProperty(isolate, global, name, array).Check();
    CompileRun("testArray[0] = 1; testArray[1] = 2; testArray.shift();");
    CcTest::CollectGarbage(OLD_SPACE);
  }
  
  
  HEAP_TEST(NumberStringCacheSize) {
    // Test that the number-string cache has not been resized in the snapshot.
    CcTest::InitializeVM();
    Isolate* isolate = CcTest::i_isolate();
    if (!isolate->snapshot_available()) return;
    Heap* heap = isolate->heap();
    CHECK_EQ(Heap::kInitialNumberStringCacheSize * 2,
             heap->number_string_cache().length());
  }
  
  
  TEST(Regress3877) {
    CcTest::InitializeVM();
    Isolate* isolate = CcTest::i_isolate();
    Factory* factory = isolate->factory();
    HandleScope scope(isolate);
    CompileRun("function cls() { this.x = 10; }");
    Handle<WeakFixedArray> weak_prototype_holder = factory->NewWeakFixedArray(1);
    {
      HandleScope inner_scope(isolate);
      v8::Local<v8::Value> result = CompileRun("cls.prototype");
      Handle<JSReceiver> proto =
          v8::Utils::OpenHandle(*v8::Local<v8::Object>::Cast(result));
      weak_prototype_holder->Set(0, HeapObjectReference::Weak(*proto));
    }
    CHECK(!weak_prototype_holder->Get(0)->IsCleared());
    CompileRun(
        "var a = { };"
        "a.x = new cls();"
        "cls.prototype = null;");
    for (int i = 0; i < 4; i++) {
      CcTest::CollectAllGarbage();
    }
    // The map of a.x keeps prototype alive
    CHECK(!weak_prototype_holder->Get(0)->IsCleared());
    // Change the map of a.x and make the previous map garbage collectable.
    CompileRun("a.x.__proto__ = {};");
    for (int i = 0; i < 4; i++) {
      CcTest::CollectAllGarbage();
    }
    CHECK(weak_prototype_holder->Get(0)->IsCleared());
  }
  
  Handle<WeakFixedArray> AddRetainedMap(Isolate* isolate, Heap* heap) {
    HandleScope inner_scope(isolate);
    Handle<Map> map = Map::Create(isolate, 1);
    v8::Local<v8::Value> result =
        CompileRun("(function () { return {x : 10}; })();");
    Handle<JSReceiver> proto =
        v8::Utils::OpenHandle(*v8::Local<v8::Object>::Cast(result));
    Map::SetPrototype(isolate, map, proto);
    heap->AddRetainedMap(map);
    Handle<WeakFixedArray> array = isolate->factory()->NewWeakFixedArray(1);
    array->Set(0, HeapObjectReference::Weak(*map));
    return inner_scope.CloseAndEscape(array);
  }
  
  
  void CheckMapRetainingFor(int n) {
    FLAG_retain_maps_for_n_gc = n;
    Isolate* isolate = CcTest::i_isolate();
    Heap* heap = isolate->heap();
    Handle<WeakFixedArray> array_with_map = AddRetainedMap(isolate, heap);
    CHECK(array_with_map->Get(0)->IsWeak());
    for (int i = 0; i < n; i++) {
      heap::SimulateIncrementalMarking(heap);
      CcTest::CollectGarbage(OLD_SPACE);
    }
    CHECK(array_with_map->Get(0)->IsWeak());
    heap::SimulateIncrementalMarking(heap);
    CcTest::CollectGarbage(OLD_SPACE);
    CHECK(array_with_map->Get(0)->IsCleared());
  }
  
  
  TEST(MapRetaining) {
    if (!FLAG_incremental_marking) return;
    ManualGCScope manual_gc_scope;
    CcTest::InitializeVM();
    v8::HandleScope scope(CcTest::isolate());
    CheckMapRetainingFor(FLAG_retain_maps_for_n_gc);
    CheckMapRetainingFor(0);
    CheckMapRetainingFor(1);
    CheckMapRetainingFor(7);
  }
  
  TEST(PreprocessStackTrace) {
    // Do not automatically trigger early GC.
    FLAG_gc_interval = -1;
    CcTest::InitializeVM();
    v8::HandleScope scope(CcTest::isolate());
    v8::TryCatch try_catch(CcTest::isolate());
    CompileRun("throw new Error();");
    CHECK(try_catch.HasCaught());
    Isolate* isolate = CcTest::i_isolate();
    Handle<Object> exception = v8::Utils::OpenHandle(*try_catch.Exception());
    Handle<Name> key = isolate->factory()->stack_trace_symbol();
    Handle<Object> stack_trace =
        Object::GetProperty(isolate, exception, key).ToHandleChecked();
    Handle<Object> code =
        Object::GetElement(isolate, stack_trace, 3).ToHandleChecked();
    CHECK(code->IsCode());
  
    CcTest::CollectAllAvailableGarbage();
  
    Handle<Object> pos =
        Object::GetElement(isolate, stack_trace, 3).ToHandleChecked();
    CHECK(pos->IsSmi());
  
    Handle<FrameArray> frame_array = Handle<FrameArray>::cast(stack_trace);
    int array_length = frame_array->FrameCount();
    for (int i = 0; i < array_length; i++) {
      Handle<Object> element =
          Object::GetElement(isolate, stack_trace, i).ToHandleChecked();
      CHECK(!element->IsCode());
    }
  }
  
  
  void AllocateInSpace(Isolate* isolate, size_t bytes, AllocationSpace space) {
    CHECK_LE(FixedArray::kHeaderSize, bytes);
    CHECK(IsAligned(bytes, kTaggedSize));
    Factory* factory = isolate->factory();
    HandleScope scope(isolate);
    AlwaysAllocateScope always_allocate(isolate);
    int elements =
        static_cast<int>((bytes - FixedArray::kHeaderSize) / kTaggedSize);
    Handle<FixedArray> array = factory->NewFixedArray(
        elements,
        space == NEW_SPACE ? AllocationType::kYoung : AllocationType::kOld);
    CHECK((space == NEW_SPACE) == Heap::InYoungGeneration(*array));
    CHECK_EQ(bytes, static_cast<size_t>(array->Size()));
  }
  
  
  TEST(NewSpaceAllocationCounter) {
    CcTest::InitializeVM();
    v8::HandleScope scope(CcTest::isolate());
    Isolate* isolate = CcTest::i_isolate();
    Heap* heap = isolate->heap();
    size_t counter1 = heap->NewSpaceAllocationCounter();
    CcTest::CollectGarbage(NEW_SPACE);
    CcTest::CollectGarbage(NEW_SPACE);  // Ensure new space is empty.
    const size_t kSize = 1024;
    AllocateInSpace(isolate, kSize, NEW_SPACE);
    size_t counter2 = heap->NewSpaceAllocationCounter();
    CHECK_EQ(kSize, counter2 - counter1);
    CcTest::CollectGarbage(NEW_SPACE);
    size_t counter3 = heap->NewSpaceAllocationCounter();
    CHECK_EQ(0U, counter3 - counter2);
    // Test counter overflow.
    size_t max_counter = static_cast<size_t>(-1);
    heap->set_new_space_allocation_counter(max_counter - 10 * kSize);
    size_t start = heap->NewSpaceAllocationCounter();
    for (int i = 0; i < 20; i++) {
      AllocateInSpace(isolate, kSize, NEW_SPACE);
      size_t counter = heap->NewSpaceAllocationCounter();
      CHECK_EQ(kSize, counter - start);
      start = counter;
    }
  }
  
  
  TEST(OldSpaceAllocationCounter) {
    CcTest::InitializeVM();
    v8::HandleScope scope(CcTest::isolate());
    Isolate* isolate = CcTest::i_isolate();
    Heap* heap = isolate->heap();
    size_t counter1 = heap->OldGenerationAllocationCounter();
    CcTest::CollectGarbage(NEW_SPACE);
    CcTest::CollectGarbage(NEW_SPACE);
    const size_t kSize = 1024;
    AllocateInSpace(isolate, kSize, OLD_SPACE);
    size_t counter2 = heap->OldGenerationAllocationCounter();
    // TODO(ulan): replace all CHECK_LE with CHECK_EQ after v8:4148 is fixed.
    CHECK_LE(kSize, counter2 - counter1);
    CcTest::CollectGarbage(NEW_SPACE);
    size_t counter3 = heap->OldGenerationAllocationCounter();
    CHECK_EQ(0u, counter3 - counter2);
    AllocateInSpace(isolate, kSize, OLD_SPACE);
    CcTest::CollectGarbage(OLD_SPACE);
    size_t counter4 = heap->OldGenerationAllocationCounter();
    CHECK_LE(kSize, counter4 - counter3);
    // Test counter overflow.
    size_t max_counter = static_cast<size_t>(-1);
    heap->set_old_generation_allocation_counter_at_last_gc(max_counter -
                                                           10 * kSize);
    size_t start = heap->OldGenerationAllocationCounter();
    for (int i = 0; i < 20; i++) {
      AllocateInSpace(isolate, kSize, OLD_SPACE);
      size_t counter = heap->OldGenerationAllocationCounter();
      CHECK_LE(kSize, counter - start);
      start = counter;
    }
  }
  
  
  static void CheckLeak(const v8::FunctionCallbackInfo<v8::Value>& args) {
    Isolate* isolate = CcTest::i_isolate();
    Object message(
        *reinterpret_cast<Address*>(isolate->pending_message_obj_address()));
    CHECK(message.IsTheHole(isolate));
  }
  
  
  TEST(MessageObjectLeak) {
    CcTest::InitializeVM();
    v8::Isolate* isolate = CcTest::isolate();
    v8::HandleScope scope(isolate);
    v8::Local<v8::ObjectTemplate> global = v8::ObjectTemplate::New(isolate);
    global->Set(
        v8::String::NewFromUtf8(isolate, "check", v8::NewStringType::kNormal)
            .ToLocalChecked(),
        v8::FunctionTemplate::New(isolate, CheckLeak));
    v8::Local<v8::Context> context = v8::Context::New(isolate, nullptr, global);
    v8::Context::Scope cscope(context);
  
    const char* test =
        "try {"
        "  throw 'message 1';"
        "} catch (e) {"
        "}"
        "check();"
        "L: try {"
        "  throw 'message 2';"
        "} finally {"
        "  break L;"
        "}"
        "check();";
    CompileRun(test);
  
    const char* flag = "--turbo-filter=*";
    FlagList::SetFlagsFromString(flag, strlen(flag));
    FLAG_always_opt = true;
  
    CompileRun(test);
  }
  
  
  static void CheckEqualSharedFunctionInfos(
      const v8::FunctionCallbackInfo<v8::Value>& args) {
    Handle<Object> obj1 = v8::Utils::OpenHandle(*args[0]);
    Handle<Object> obj2 = v8::Utils::OpenHandle(*args[1]);
    Handle<JSFunction> fun1 = Handle<JSFunction>::cast(obj1);
    Handle<JSFunction> fun2 = Handle<JSFunction>::cast(obj2);
    CHECK(fun1->shared() == fun2->shared());
  }
  
  
  static void RemoveCodeAndGC(const v8::FunctionCallbackInfo<v8::Value>& args) {
    Isolate* isolate = CcTest::i_isolate();
    Handle<Object> obj = v8::Utils::OpenHandle(*args[0]);
    Handle<JSFunction> fun = Handle<JSFunction>::cast(obj);
    // Bytecode is code too.
    SharedFunctionInfo::DiscardCompiled(isolate, handle(fun->shared(), isolate));
    fun->set_code(*BUILTIN_CODE(isolate, CompileLazy));
    CcTest::CollectAllAvailableGarbage();
  }
  
  
  TEST(CanonicalSharedFunctionInfo) {
    CcTest::InitializeVM();
    v8::Isolate* isolate = CcTest::isolate();
    v8::HandleScope scope(isolate);
    v8::Local<v8::ObjectTemplate> global = v8::ObjectTemplate::New(isolate);
    global->Set(isolate, "check", v8::FunctionTemplate::New(
                                      isolate, CheckEqualSharedFunctionInfos));
    global->Set(isolate, "remove",
                v8::FunctionTemplate::New(isolate, RemoveCodeAndGC));
    v8::Local<v8::Context> context = v8::Context::New(isolate, nullptr, global);
    v8::Context::Scope cscope(context);
    CompileRun(
        "function f() { return function g() {}; }"
        "var g1 = f();"
        "remove(f);"
        "var g2 = f();"
        "check(g1, g2);");
  
    CompileRun(
        "function f() { return (function() { return function g() {}; })(); }"
        "var g1 = f();"
        "remove(f);"
        "var g2 = f();"
        "check(g1, g2);");
  }
  
  
  TEST(ScriptIterator) {
    CcTest::InitializeVM();
    v8::HandleScope scope(CcTest::isolate());
    Isolate* isolate = CcTest::i_isolate();
    Heap* heap = CcTest::heap();
    LocalContext context;
  
    CcTest::CollectAllGarbage();
  
    int script_count = 0;
    {
      HeapObjectIterator it(heap);
      for (HeapObject obj = it.Next(); !obj.is_null(); obj = it.Next()) {
        if (obj.IsScript()) script_count++;
      }
    }
  
    {
      Script::Iterator iterator(isolate);
      for (Script script = iterator.Next(); !script.is_null();
           script = iterator.Next()) {
        script_count--;
      }
    }
  
    CHECK_EQ(0, script_count);
  }
  
  
  TEST(SharedFunctionInfoIterator) {
    CcTest::InitializeVM();
    v8::HandleScope scope(CcTest::isolate());
    Isolate* isolate = CcTest::i_isolate();
    Heap* heap = CcTest::heap();
    LocalContext context;
  
    CcTest::CollectAllGarbage();
    CcTest::CollectAllGarbage();
  
    int sfi_count = 0;
    {
      HeapObjectIterator it(heap);
      for (HeapObject obj = it.Next(); !obj.is_null(); obj = it.Next()) {
        if (!obj.IsSharedFunctionInfo()) continue;
        sfi_count++;
      }
    }
  
    {
      SharedFunctionInfo::GlobalIterator iterator(isolate);
      while (!iterator.Next().is_null()) sfi_count--;
    }
  
    CHECK_EQ(0, sfi_count);
  }
  
  // This is the same as Factory::NewByteArray, except it doesn't retry on
  // allocation failure.
  AllocationResult HeapTester::AllocateByteArrayForTest(
      Heap* heap, int length, AllocationType allocation_type) {
    DCHECK(length >= 0 && length <= ByteArray::kMaxLength);
    int size = ByteArray::SizeFor(length);
    HeapObject result;
    {
      AllocationResult allocation = heap->AllocateRaw(size, allocation_type);
      if (!allocation.To(&result)) return allocation;
    }
  
    result.set_map_after_allocation(ReadOnlyRoots(heap).byte_array_map(),
                                    SKIP_WRITE_BARRIER);
    ByteArray::cast(result).set_length(length);
    ByteArray::cast(result).clear_padding();
    return result;
  }
  
  HEAP_TEST(Regress587004) {
    ManualGCScope manual_gc_scope;
  #ifdef VERIFY_HEAP
    FLAG_verify_heap = false;
  #endif
    CcTest::InitializeVM();
    v8::HandleScope scope(CcTest::isolate());
    Heap* heap = CcTest::heap();
    Isolate* isolate = CcTest::i_isolate();
    Factory* factory = isolate->factory();
    const int N =
        (kMaxRegularHeapObjectSize - FixedArray::kHeaderSize) / kTaggedSize;
    Handle<FixedArray> array = factory->NewFixedArray(N, AllocationType::kOld);
    CHECK(heap->old_space()->Contains(*array));
    Handle<Object> number = factory->NewHeapNumber(1.0);
    CHECK(Heap::InYoungGeneration(*number));
    for (int i = 0; i < N; i++) {
      array->set(i, *number);
    }
    CcTest::CollectGarbage(OLD_SPACE);
    heap::SimulateFullSpace(heap->old_space());
    heap->RightTrimFixedArray(*array, N - 1);
    heap->mark_compact_collector()->EnsureSweepingCompleted();
    ByteArray byte_array;
    const int M = 256;
    // Don't allow old space expansion. The test works without this flag too,
    // but becomes very slow.
    heap->set_force_oom(true);
    while (
        AllocateByteArrayForTest(heap, M, AllocationType::kOld).To(&byte_array)) {
      for (int j = 0; j < M; j++) {
        byte_array.set(j, 0x31);
      }
    }
    // Re-enable old space expansion to avoid OOM crash.
    heap->set_force_oom(false);
    CcTest::CollectGarbage(NEW_SPACE);
  }
  
  HEAP_TEST(Regress589413) {
    if (!FLAG_incremental_marking) return;
    FLAG_stress_compaction = true;
    FLAG_manual_evacuation_candidates_selection = true;
    FLAG_parallel_compaction = false;
    ManualGCScope manual_gc_scope;
    CcTest::InitializeVM();
    v8::HandleScope scope(CcTest::isolate());
    Heap* heap = CcTest::heap();
    // Get the heap in clean state.
    CcTest::CollectGarbage(OLD_SPACE);
    CcTest::CollectGarbage(OLD_SPACE);
    Isolate* isolate = CcTest::i_isolate();
    Factory* factory = isolate->factory();
    // Fill the new space with byte arrays with elements looking like pointers.
    const int M = 256;
    ByteArray byte_array;
    while (AllocateByteArrayForTest(heap, M, AllocationType::kYoung)
               .To(&byte_array)) {
      for (int j = 0; j < M; j++) {
        byte_array.set(j, 0x31);
      }
      // Add the array in root set.
      handle(byte_array, isolate);
    }
    // Make sure the byte arrays will be promoted on the next GC.
    CcTest::CollectGarbage(NEW_SPACE);
    // This number is close to large free list category threshold.
    const int N = 0x3EEE;
    {
      std::vector<FixedArray> arrays;
      std::set<Page*> pages;
      FixedArray array;
      // Fill all pages with fixed arrays.
      heap->set_force_oom(true);
      while (
          AllocateFixedArrayForTest(heap, N, AllocationType::kOld).To(&array)) {
        arrays.push_back(array);
        pages.insert(Page::FromHeapObject(array));
        // Add the array in root set.
        handle(array, isolate);
      }
      // Expand and full one complete page with fixed arrays.
      heap->set_force_oom(false);
      while (
          AllocateFixedArrayForTest(heap, N, AllocationType::kOld).To(&array)) {
        arrays.push_back(array);
        pages.insert(Page::FromHeapObject(array));
        // Add the array in root set.
        handle(array, isolate);
        // Do not expand anymore.
        heap->set_force_oom(true);
      }
      // Expand and mark the new page as evacuation candidate.
      heap->set_force_oom(false);
      {
        AlwaysAllocateScope always_allocate(isolate);
        Handle<HeapObject> ec_obj =
            factory->NewFixedArray(5000, AllocationType::kOld);
        Page* ec_page = Page::FromHeapObject(*ec_obj);
        heap::ForceEvacuationCandidate(ec_page);
        // Make all arrays point to evacuation candidate so that
        // slots are recorded for them.
        for (size_t j = 0; j < arrays.size(); j++) {
          array = arrays[j];
          for (int i = 0; i < N; i++) {
            array.set(i, *ec_obj);
          }
        }
      }
      heap::SimulateIncrementalMarking(heap);
      for (size_t j = 0; j < arrays.size(); j++) {
        heap->RightTrimFixedArray(arrays[j], N - 1);
      }
    }
    // Force allocation from the free list.
    heap->set_force_oom(true);
    CcTest::CollectGarbage(OLD_SPACE);
  }
  
  TEST(Regress598319) {
    if (!FLAG_incremental_marking) return;
    ManualGCScope manual_gc_scope;
    // This test ensures that no white objects can cross the progress bar of large
    // objects during incremental marking. It checks this by using Shift() during
    // incremental marking.
    CcTest::InitializeVM();
    v8::HandleScope scope(CcTest::isolate());
    Heap* heap = CcTest::heap();
    Isolate* isolate = heap->isolate();
  
    // The size of the array should be larger than kProgressBarScanningChunk.
    const int kNumberOfObjects = Max(FixedArray::kMaxRegularLength + 1, 128 * KB);
  
    struct Arr {
      Arr(Isolate* isolate, int number_of_objects) {
        root = isolate->factory()->NewFixedArray(1, AllocationType::kOld);
        {
          // Temporary scope to avoid getting any other objects into the root set.
          v8::HandleScope scope(CcTest::isolate());
          Handle<FixedArray> tmp = isolate->factory()->NewFixedArray(
              number_of_objects, AllocationType::kOld);
          root->set(0, *tmp);
          for (int i = 0; i < get().length(); i++) {
            tmp = isolate->factory()->NewFixedArray(100, AllocationType::kOld);
            get().set(i, *tmp);
          }
        }
      }
  
      FixedArray get() { return FixedArray::cast(root->get(0)); }
  
      Handle<FixedArray> root;
    } arr(isolate, kNumberOfObjects);
  
    CHECK_EQ(arr.get().length(), kNumberOfObjects);
    CHECK(heap->lo_space()->Contains(arr.get()));
    LargePage* page = LargePage::FromHeapObject(arr.get());
    CHECK_NOT_NULL(page);
  
    // GC to cleanup state
    CcTest::CollectGarbage(OLD_SPACE);
    MarkCompactCollector* collector = heap->mark_compact_collector();
    if (collector->sweeping_in_progress()) {
      collector->EnsureSweepingCompleted();
    }
  
    CHECK(heap->lo_space()->Contains(arr.get()));
    IncrementalMarking* marking = heap->incremental_marking();
    IncrementalMarking::MarkingState* marking_state = marking->marking_state();
    CHECK(marking_state->IsWhite(arr.get()));
    for (int i = 0; i < arr.get().length(); i++) {
      HeapObject arr_value = HeapObject::cast(arr.get().get(i));
      CHECK(marking_state->IsWhite(arr_value));
    }
  
    // Start incremental marking.
    CHECK(marking->IsMarking() || marking->IsStopped());
    if (marking->IsStopped()) {
      heap->StartIncrementalMarking(i::Heap::kNoGCFlags,
                                    i::GarbageCollectionReason::kTesting);
    }
    CHECK(marking->IsMarking());
  
    // Check that we have not marked the interesting array during root scanning.
    for (int i = 0; i < arr.get().length(); i++) {
      HeapObject arr_value = HeapObject::cast(arr.get().get(i));
      CHECK(marking_state->IsWhite(arr_value));
    }
  
    // Now we search for a state where we are in incremental marking and have
    // only partially marked the large object.
    const double kSmallStepSizeInMs = 0.1;
    while (!marking->IsComplete()) {
      marking->V8Step(kSmallStepSizeInMs,
                      i::IncrementalMarking::NO_GC_VIA_STACK_GUARD,
                      StepOrigin::kV8);
      if (page->IsFlagSet(Page::HAS_PROGRESS_BAR) && page->ProgressBar() > 0) {
        CHECK_NE(page->ProgressBar(), arr.get().Size());
        {
          // Shift by 1, effectively moving one white object across the progress
          // bar, meaning that we will miss marking it.
          v8::HandleScope scope(CcTest::isolate());
          Handle<JSArray> js_array = isolate->factory()->NewJSArrayWithElements(
              Handle<FixedArray>(arr.get(), isolate));
          js_array->GetElementsAccessor()->Shift(js_array);
        }
        break;
      }
    }
  
    // Finish marking with bigger steps to speed up test.
    const double kLargeStepSizeInMs = 1000;
    while (!marking->IsComplete()) {
      marking->V8Step(kLargeStepSizeInMs,
                      i::IncrementalMarking::NO_GC_VIA_STACK_GUARD,
                      StepOrigin::kV8);
      if (marking->IsReadyToOverApproximateWeakClosure()) {
        marking->FinalizeIncrementally();
      }
    }
    CHECK(marking->IsComplete());
  
    // All objects need to be black after marking. If a white object crossed the
    // progress bar, we would fail here.
    for (int i = 0; i < arr.get().length(); i++) {
      HeapObject arr_value = HeapObject::cast(arr.get().get(i));
      CHECK(marking_state->IsBlack(arr_value));
    }
  }
  
  Handle<FixedArray> ShrinkArrayAndCheckSize(Heap* heap, int length) {
    // Make sure there is no garbage and the compilation cache is empty.
    for (int i = 0; i < 5; i++) {
      CcTest::CollectAllGarbage();
    }
    heap->mark_compact_collector()->EnsureSweepingCompleted();
    size_t size_before_allocation = heap->SizeOfObjects();
    Handle<FixedArray> array =
        heap->isolate()->factory()->NewFixedArray(length, AllocationType::kOld);
    size_t size_after_allocation = heap->SizeOfObjects();
    CHECK_EQ(size_after_allocation, size_before_allocation + array->Size());
    array->Shrink(heap->isolate(), 1);
    size_t size_after_shrinking = heap->SizeOfObjects();
    // Shrinking does not change the space size immediately.
    CHECK_EQ(size_after_allocation, size_after_shrinking);
    // GC and sweeping updates the size to acccount for shrinking.
    CcTest::CollectAllGarbage();
    heap->mark_compact_collector()->EnsureSweepingCompleted();
    intptr_t size_after_gc = heap->SizeOfObjects();
    CHECK_EQ(size_after_gc, size_before_allocation + array->Size());
    return array;
  }
  
  TEST(Regress609761) {
    CcTest::InitializeVM();
    v8::HandleScope scope(CcTest::isolate());
    Heap* heap = CcTest::heap();
    int length = kMaxRegularHeapObjectSize / kTaggedSize + 1;
    Handle<FixedArray> array = ShrinkArrayAndCheckSize(heap, length);
    CHECK(heap->lo_space()->Contains(*array));
  }
  
  TEST(LiveBytes) {
    CcTest::InitializeVM();
    v8::HandleScope scope(CcTest::isolate());
    Heap* heap = CcTest::heap();
    Handle<FixedArray> array = ShrinkArrayAndCheckSize(heap, 2000);
    CHECK(heap->old_space()->Contains(*array));
  }
  
  TEST(Regress615489) {
    if (!FLAG_incremental_marking) return;
    CcTest::InitializeVM();
    v8::HandleScope scope(CcTest::isolate());
    Heap* heap = CcTest::heap();
    Isolate* isolate = heap->isolate();
    CcTest::CollectAllGarbage();
  
    i::MarkCompactCollector* collector = heap->mark_compact_collector();
    i::IncrementalMarking* marking = heap->incremental_marking();
    if (collector->sweeping_in_progress()) {
      collector->EnsureSweepingCompleted();
    }
    CHECK(marking->IsMarking() || marking->IsStopped());
    if (marking->IsStopped()) {
      heap->StartIncrementalMarking(i::Heap::kNoGCFlags,
                                    i::GarbageCollectionReason::kTesting);
    }
    CHECK(marking->IsMarking());
    marking->StartBlackAllocationForTesting();
    {
      AlwaysAllocateScope always_allocate(CcTest::i_isolate());
      v8::HandleScope inner(CcTest::isolate());
      isolate->factory()->NewFixedArray(500, AllocationType::kOld)->Size();
    }
    const double kStepSizeInMs = 100;
    while (!marking->IsComplete()) {
      marking->V8Step(kStepSizeInMs, i::IncrementalMarking::NO_GC_VIA_STACK_GUARD,
                      StepOrigin::kV8);
      if (marking->IsReadyToOverApproximateWeakClosure()) {
        marking->FinalizeIncrementally();
      }
    }
    CHECK(marking->IsComplete());
    intptr_t size_before = heap->SizeOfObjects();
    CcTest::CollectAllGarbage();
    intptr_t size_after = heap->SizeOfObjects();
    // Live size does not increase after garbage collection.
    CHECK_LE(size_after, size_before);
  }
  
  class StaticOneByteResource : public v8::String::ExternalOneByteStringResource {
   public:
    explicit StaticOneByteResource(const char* data) : data_(data) {}
  
    ~StaticOneByteResource() override = default;
  
    const char* data() const override { return data_; }
  
    size_t length() const override { return strlen(data_); }
  
   private:
    const char* data_;
  };
  
  TEST(Regress631969) {
    if (!FLAG_incremental_marking) return;
    FLAG_manual_evacuation_candidates_selection = true;
    FLAG_parallel_compaction = false;
    ManualGCScope manual_gc_scope;
    CcTest::InitializeVM();
    v8::HandleScope scope(CcTest::isolate());
    Heap* heap = CcTest::heap();
    // Get the heap in clean state.
    CcTest::CollectGarbage(OLD_SPACE);
    CcTest::CollectGarbage(OLD_SPACE);
    Isolate* isolate = CcTest::i_isolate();
    Factory* factory = isolate->factory();
    // Allocate two strings in a fresh page and mark the page as evacuation
    // candidate.
    heap::SimulateFullSpace(heap->old_space());
    Handle<String> s1 =
        factory->NewStringFromStaticChars("123456789", AllocationType::kOld);
    Handle<String> s2 =
        factory->NewStringFromStaticChars("01234", AllocationType::kOld);
    heap::ForceEvacuationCandidate(Page::FromHeapObject(*s1));
  
    heap::SimulateIncrementalMarking(heap, false);
  
    // Allocate a cons string and promote it to a fresh page in the old space.
    heap::SimulateFullSpace(heap->old_space());
    Handle<String> s3;
    factory->NewConsString(s1, s2).ToHandle(&s3);
    CcTest::CollectGarbage(NEW_SPACE);
    CcTest::CollectGarbage(NEW_SPACE);
  
    // Finish incremental marking.
    const double kStepSizeInMs = 100;
    IncrementalMarking* marking = heap->incremental_marking();
    while (!marking->IsComplete()) {
      marking->V8Step(kStepSizeInMs, i::IncrementalMarking::NO_GC_VIA_STACK_GUARD,
                      StepOrigin::kV8);
      if (marking->IsReadyToOverApproximateWeakClosure()) {
        marking->FinalizeIncrementally();
      }
    }
  
    {
      StaticOneByteResource external_string("12345678901234");
      s3->MakeExternal(&external_string);
      CcTest::CollectGarbage(OLD_SPACE);
      // This avoids the GC from trying to free stack allocated resources.
      i::Handle<i::ExternalOneByteString>::cast(s3)->SetResource(isolate,
                                                                 nullptr);
    }
  }
  
  TEST(LeftTrimFixedArrayInBlackArea) {
    if (!FLAG_incremental_marking) return;
    CcTest::InitializeVM();
    v8::HandleScope scope(CcTest::isolate());
    Heap* heap = CcTest::heap();
    Isolate* isolate = heap->isolate();
    CcTest::CollectAllGarbage();
  
    i::MarkCompactCollector* collector = heap->mark_compact_collector();
    i::IncrementalMarking* marking = heap->incremental_marking();
    if (collector->sweeping_in_progress()) {
      collector->EnsureSweepingCompleted();
    }
    CHECK(marking->IsMarking() || marking->IsStopped());
    if (marking->IsStopped()) {
      heap->StartIncrementalMarking(i::Heap::kNoGCFlags,
                                    i::GarbageCollectionReason::kTesting);
    }
    CHECK(marking->IsMarking());
    marking->StartBlackAllocationForTesting();
  
    // Ensure that we allocate a new page, set up a bump pointer area, and
    // perform the allocation in a black area.
    heap::SimulateFullSpace(heap->old_space());
    isolate->factory()->NewFixedArray(4, AllocationType::kOld);
    Handle<FixedArray> array =
        isolate->factory()->NewFixedArray(50, AllocationType::kOld);
    CHECK(heap->old_space()->Contains(*array));
    IncrementalMarking::MarkingState* marking_state = marking->marking_state();
    CHECK(marking_state->IsBlack(*array));
  
    // Now left trim the allocated black area. A filler has to be installed
    // for the trimmed area and all mark bits of the trimmed area have to be
    // cleared.
    FixedArrayBase trimmed = heap->LeftTrimFixedArray(*array, 10);
    CHECK(marking_state->IsBlack(trimmed));
  
    heap::GcAndSweep(heap, OLD_SPACE);
  }
  
  TEST(ContinuousLeftTrimFixedArrayInBlackArea) {
    if (!FLAG_incremental_marking) return;
    CcTest::InitializeVM();
    v8::HandleScope scope(CcTest::isolate());
    Heap* heap = CcTest::heap();
    Isolate* isolate = heap->isolate();
    CcTest::CollectAllGarbage();
  
    i::MarkCompactCollector* collector = heap->mark_compact_collector();
    i::IncrementalMarking* marking = heap->incremental_marking();
    if (collector->sweeping_in_progress()) {
      collector->EnsureSweepingCompleted();
    }
    CHECK(marking->IsMarking() || marking->IsStopped());
    if (marking->IsStopped()) {
      heap->StartIncrementalMarking(i::Heap::kNoGCFlags,
                                    i::GarbageCollectionReason::kTesting);
    }
    CHECK(marking->IsMarking());
    marking->StartBlackAllocationForTesting();
  
    // Ensure that we allocate a new page, set up a bump pointer area, and
    // perform the allocation in a black area.
    heap::SimulateFullSpace(heap->old_space());
    isolate->factory()->NewFixedArray(10, AllocationType::kOld);
  
    // Allocate the fixed array that will be trimmed later.
    Handle<FixedArray> array =
        isolate->factory()->NewFixedArray(100, AllocationType::kOld);
    Address start_address = array->address();
    Address end_address = start_address + array->Size();
    Page* page = Page::FromAddress(start_address);
    IncrementalMarking::NonAtomicMarkingState* marking_state =
        marking->non_atomic_marking_state();
    CHECK(marking_state->IsBlack(*array));
    CHECK(marking_state->bitmap(page)->AllBitsSetInRange(
        page->AddressToMarkbitIndex(start_address),
        page->AddressToMarkbitIndex(end_address)));
    CHECK(heap->old_space()->Contains(*array));
  
    FixedArrayBase previous = *array;
    FixedArrayBase trimmed;
  
    // First trim in one word steps.
    for (int i = 0; i < 10; i++) {
      trimmed = heap->LeftTrimFixedArray(previous, 1);
      HeapObject filler = HeapObject::FromAddress(previous.address());
      CHECK(filler.IsFiller());
      CHECK(marking_state->IsBlack(trimmed));
      CHECK(marking_state->IsBlack(previous));
      previous = trimmed;
    }
  
    // Then trim in two and three word steps.
    for (int i = 2; i <= 3; i++) {
      for (int j = 0; j < 10; j++) {
        trimmed = heap->LeftTrimFixedArray(previous, i);
        HeapObject filler = HeapObject::FromAddress(previous.address());
        CHECK(filler.IsFiller());
        CHECK(marking_state->IsBlack(trimmed));
        CHECK(marking_state->IsBlack(previous));
        previous = trimmed;
      }
    }
  
    heap::GcAndSweep(heap, OLD_SPACE);
  }
  
  TEST(ContinuousRightTrimFixedArrayInBlackArea) {
    if (!FLAG_incremental_marking) return;
    CcTest::InitializeVM();
    v8::HandleScope scope(CcTest::isolate());
    Heap* heap = CcTest::heap();
    Isolate* isolate = CcTest::i_isolate();
    CcTest::CollectAllGarbage();
  
    i::MarkCompactCollector* collector = heap->mark_compact_collector();
    i::IncrementalMarking* marking = heap->incremental_marking();
    if (collector->sweeping_in_progress()) {
      collector->EnsureSweepingCompleted();
    }
    CHECK(marking->IsMarking() || marking->IsStopped());
    if (marking->IsStopped()) {
      heap->StartIncrementalMarking(i::Heap::kNoGCFlags,
                                    i::GarbageCollectionReason::kTesting);
    }
    CHECK(marking->IsMarking());
    marking->StartBlackAllocationForTesting();
  
    // Ensure that we allocate a new page, set up a bump pointer area, and
    // perform the allocation in a black area.
    heap::SimulateFullSpace(heap->old_space());
    isolate->factory()->NewFixedArray(10, AllocationType::kOld);
  
    // Allocate the fixed array that will be trimmed later.
    Handle<FixedArray> array =
        CcTest::i_isolate()->factory()->NewFixedArray(100, AllocationType::kOld);
    Address start_address = array->address();
    Address end_address = start_address + array->Size();
    Page* page = Page::FromAddress(start_address);
    IncrementalMarking::NonAtomicMarkingState* marking_state =
        marking->non_atomic_marking_state();
    CHECK(marking_state->IsBlack(*array));
  
    CHECK(marking_state->bitmap(page)->AllBitsSetInRange(
        page->AddressToMarkbitIndex(start_address),
        page->AddressToMarkbitIndex(end_address)));
    CHECK(heap->old_space()->Contains(*array));
  
    // Trim it once by one word to make checking for white marking color uniform.
    Address previous = end_address - kTaggedSize;
    isolate->heap()->RightTrimFixedArray(*array, 1);
  
    HeapObject filler = HeapObject::FromAddress(previous);
    CHECK(filler.IsFiller());
    CHECK(marking_state->IsImpossible(filler));
  
    // Trim 10 times by one, two, and three word.
    for (int i = 1; i <= 3; i++) {
      for (int j = 0; j < 10; j++) {
        previous -= kTaggedSize * i;
        isolate->heap()->RightTrimFixedArray(*array, i);
        HeapObject filler = HeapObject::FromAddress(previous);
        CHECK(filler.IsFiller());
        CHECK(marking_state->IsWhite(filler));
      }
    }
  
    heap::GcAndSweep(heap, OLD_SPACE);
  }
  
  TEST(Regress618958) {
    if (!FLAG_incremental_marking) return;
    CcTest::InitializeVM();
    v8::HandleScope scope(CcTest::isolate());
    Heap* heap = CcTest::heap();
    bool isolate_is_locked = true;
    CcTest::isolate()->AdjustAmountOfExternalAllocatedMemory(100 * MB);
    int mark_sweep_count_before = heap->ms_count();
    heap->MemoryPressureNotification(MemoryPressureLevel::kCritical,
                                     isolate_is_locked);
    int mark_sweep_count_after = heap->ms_count();
    int mark_sweeps_performed = mark_sweep_count_after - mark_sweep_count_before;
    // The memory pressuer handler either performed two GCs or performed one and
    // started incremental marking.
    CHECK(mark_sweeps_performed == 2 ||
          (mark_sweeps_performed == 1 &&
           !heap->incremental_marking()->IsStopped()));
  }
  
  TEST(YoungGenerationLargeObjectAllocationScavenge) {
    if (FLAG_minor_mc) return;
    FLAG_young_generation_large_objects = true;
    CcTest::InitializeVM();
    v8::HandleScope scope(CcTest::isolate());
    Heap* heap = CcTest::heap();
    Isolate* isolate = heap->isolate();
    if (!isolate->serializer_enabled()) return;
  
    // TODO(hpayer): Update the test as soon as we have a tenure limit for LO.
    Handle<FixedArray> array_small = isolate->factory()->NewFixedArray(200000);
    MemoryChunk* chunk = MemoryChunk::FromHeapObject(*array_small);
    CHECK_EQ(NEW_LO_SPACE, chunk->owner_identity());
    CHECK(chunk->IsFlagSet(MemoryChunk::LARGE_PAGE));
    CHECK(chunk->IsFlagSet(MemoryChunk::TO_PAGE));
  
    Handle<Object> number = isolate->factory()->NewHeapNumber(123.456);
    array_small->set(0, *number);
  
    CcTest::CollectGarbage(NEW_SPACE);
  
    // After the first young generation GC array_small will be in the old
    // generation large object space.
    chunk = MemoryChunk::FromHeapObject(*array_small);
    CHECK_EQ(LO_SPACE, chunk->owner_identity());
    CHECK(!chunk->InYoungGeneration());
  
    CcTest::CollectAllAvailableGarbage();
  }
  
  TEST(YoungGenerationLargeObjectAllocationMarkCompact) {
    if (FLAG_minor_mc) return;
    FLAG_young_generation_large_objects = true;
    CcTest::InitializeVM();
    v8::HandleScope scope(CcTest::isolate());
    Heap* heap = CcTest::heap();
    Isolate* isolate = heap->isolate();
    if (!isolate->serializer_enabled()) return;
  
    // TODO(hpayer): Update the test as soon as we have a tenure limit for LO.
    Handle<FixedArray> array_small = isolate->factory()->NewFixedArray(200000);
    MemoryChunk* chunk = MemoryChunk::FromHeapObject(*array_small);
    CHECK_EQ(NEW_LO_SPACE, chunk->owner_identity());
    CHECK(chunk->IsFlagSet(MemoryChunk::LARGE_PAGE));
    CHECK(chunk->IsFlagSet(MemoryChunk::TO_PAGE));
  
    Handle<Object> number = isolate->factory()->NewHeapNumber(123.456);
    array_small->set(0, *number);
  
    CcTest::CollectGarbage(OLD_SPACE);
  
    // After the first full GC array_small will be in the old generation
    // large object space.
    chunk = MemoryChunk::FromHeapObject(*array_small);
    CHECK_EQ(LO_SPACE, chunk->owner_identity());
    CHECK(!chunk->InYoungGeneration());
  
    CcTest::CollectAllAvailableGarbage();
  }
  
  TEST(YoungGenerationLargeObjectAllocationReleaseScavenger) {
    if (FLAG_minor_mc) return;
    FLAG_young_generation_large_objects = true;
    CcTest::InitializeVM();
    v8::HandleScope scope(CcTest::isolate());
    Heap* heap = CcTest::heap();
    Isolate* isolate = heap->isolate();
    if (!isolate->serializer_enabled()) return;
  
    {
      HandleScope scope(isolate);
      for (int i = 0; i < 10; i++) {
        Handle<FixedArray> array_small = isolate->factory()->NewFixedArray(20000);
        MemoryChunk* chunk = MemoryChunk::FromHeapObject(*array_small);
        CHECK_EQ(NEW_LO_SPACE, chunk->owner_identity());
        CHECK(chunk->IsFlagSet(MemoryChunk::TO_PAGE));
      }
    }
  
    CcTest::CollectGarbage(NEW_SPACE);
    CHECK(isolate->heap()->new_lo_space()->IsEmpty());
    CHECK_EQ(0, isolate->heap()->new_lo_space()->Size());
    CHECK_EQ(0, isolate->heap()->new_lo_space()->SizeOfObjects());
    CHECK(isolate->heap()->lo_space()->IsEmpty());
    CHECK_EQ(0, isolate->heap()->lo_space()->Size());
    CHECK_EQ(0, isolate->heap()->lo_space()->SizeOfObjects());
  }
  
  TEST(UncommitUnusedLargeObjectMemory) {
    CcTest::InitializeVM();
    v8::HandleScope scope(CcTest::isolate());
    Heap* heap = CcTest::heap();
    Isolate* isolate = heap->isolate();
  
    Handle<FixedArray> array =
        isolate->factory()->NewFixedArray(200000, AllocationType::kOld);
    MemoryChunk* chunk = MemoryChunk::FromHeapObject(*array);
    CHECK(chunk->owner_identity() == LO_SPACE);
  
    intptr_t size_before = array->Size();
    size_t committed_memory_before = chunk->CommittedPhysicalMemory();
  
    array->Shrink(isolate, 1);
    CHECK(array->Size() < size_before);
  
    CcTest::CollectAllGarbage();
    CHECK(chunk->CommittedPhysicalMemory() < committed_memory_before);
    size_t shrinked_size = RoundUp(
        (array->address() - chunk->address()) + array->Size(), CommitPageSize());
    CHECK_EQ(shrinked_size, chunk->CommittedPhysicalMemory());
  }
  
  TEST(RememberedSetRemoveRange) {
    CcTest::InitializeVM();
    v8::HandleScope scope(CcTest::isolate());
    Heap* heap = CcTest::heap();
    Isolate* isolate = heap->isolate();
  
    Handle<FixedArray> array = isolate->factory()->NewFixedArray(
        Page::kPageSize / kTaggedSize, AllocationType::kOld);
    MemoryChunk* chunk = MemoryChunk::FromHeapObject(*array);
    CHECK(chunk->owner_identity() == LO_SPACE);
    Address start = array->address();
    // Maps slot to boolean indicator of whether the slot should be in the set.
    std::map<Address, bool> slots;
    slots[start + 0] = true;
    slots[start + kTaggedSize] = true;
    slots[start + Page::kPageSize - kTaggedSize] = true;
    slots[start + Page::kPageSize] = true;
    slots[start + Page::kPageSize + kTaggedSize] = true;
    slots[chunk->area_end() - kTaggedSize] = true;
  
    for (auto x : slots) {
      RememberedSet<OLD_TO_NEW>::Insert(chunk, x.first);
    }
  
    RememberedSet<OLD_TO_NEW>::Iterate(chunk,
                                       [&slots](MaybeObjectSlot slot) {
                                         CHECK(slots[slot.address()]);
                                         return KEEP_SLOT;
                                       },
                                       SlotSet::PREFREE_EMPTY_BUCKETS);
  
    RememberedSet<OLD_TO_NEW>::RemoveRange(chunk, start, start + kTaggedSize,
                                           SlotSet::FREE_EMPTY_BUCKETS);
    slots[start] = false;
    RememberedSet<OLD_TO_NEW>::Iterate(chunk,
                                       [&slots](MaybeObjectSlot slot) {
                                         CHECK(slots[slot.address()]);
                                         return KEEP_SLOT;
                                       },
                                       SlotSet::PREFREE_EMPTY_BUCKETS);
  
    RememberedSet<OLD_TO_NEW>::RemoveRange(chunk, start + kTaggedSize,
                                           start + Page::kPageSize,
                                           SlotSet::FREE_EMPTY_BUCKETS);
    slots[start + kTaggedSize] = false;
    slots[start + Page::kPageSize - kTaggedSize] = false;
    RememberedSet<OLD_TO_NEW>::Iterate(chunk,
                                       [&slots](MaybeObjectSlot slot) {
                                         CHECK(slots[slot.address()]);
                                         return KEEP_SLOT;
                                       },
                                       SlotSet::PREFREE_EMPTY_BUCKETS);
  
    RememberedSet<OLD_TO_NEW>::RemoveRange(chunk, start,
                                           start + Page::kPageSize + kTaggedSize,
                                           SlotSet::FREE_EMPTY_BUCKETS);
    slots[start + Page::kPageSize] = false;
    RememberedSet<OLD_TO_NEW>::Iterate(chunk,
                                       [&slots](MaybeObjectSlot slot) {
                                         CHECK(slots[slot.address()]);
                                         return KEEP_SLOT;
                                       },
                                       SlotSet::PREFREE_EMPTY_BUCKETS);
  
    RememberedSet<OLD_TO_NEW>::RemoveRange(chunk, chunk->area_end() - kTaggedSize,
                                           chunk->area_end(),
                                           SlotSet::FREE_EMPTY_BUCKETS);
    slots[chunk->area_end() - kTaggedSize] = false;
    RememberedSet<OLD_TO_NEW>::Iterate(chunk,
                                       [&slots](MaybeObjectSlot slot) {
                                         CHECK(slots[slot.address()]);
                                         return KEEP_SLOT;
                                       },
                                       SlotSet::PREFREE_EMPTY_BUCKETS);
  }
  
  HEAP_TEST(Regress670675) {
    if (!FLAG_incremental_marking) return;
    FLAG_stress_incremental_marking = false;
    CcTest::InitializeVM();
    v8::HandleScope scope(CcTest::isolate());
    Heap* heap = CcTest::heap();
    Isolate* isolate = heap->isolate();
    i::MarkCompactCollector* collector = heap->mark_compact_collector();
    CcTest::CollectAllGarbage();
  
    if (collector->sweeping_in_progress()) {
      collector->EnsureSweepingCompleted();
    }
    i::IncrementalMarking* marking = CcTest::heap()->incremental_marking();
    if (marking->IsStopped()) {
      marking->Start(i::GarbageCollectionReason::kTesting);
    }
    size_t array_length = 128 * KB;
    size_t n = heap->OldGenerationSpaceAvailable() / array_length;
    for (size_t i = 0; i < n + 40; i++) {
      {
        HandleScope inner_scope(isolate);
        isolate->factory()->NewFixedArray(static_cast<int>(array_length),
                                          AllocationType::kOld);
      }
      if (marking->IsStopped()) break;
      double deadline = heap->MonotonicallyIncreasingTimeInMs() + 1;
      marking->AdvanceWithDeadline(
          deadline, IncrementalMarking::GC_VIA_STACK_GUARD, StepOrigin::kV8);
    }
    DCHECK(marking->IsStopped());
  }
  
  namespace {
  Handle<Code> GenerateDummyImmovableCode(Isolate* isolate) {
    Assembler assm(AssemblerOptions{});
  
    const int kNumberOfNops = 1 << 10;
    for (int i = 0; i < kNumberOfNops; i++) {
      assm.nop();  // supported on all architectures
    }
  
    CodeDesc desc;
    assm.GetCode(isolate, &desc);
    Handle<Code> code =
        Factory::CodeBuilder(isolate, desc, Code::STUB).set_immovable().Build();
    CHECK(code->IsCode());
  
    return code;
  }
  }  // namespace
  
  HEAP_TEST(Regress5831) {
    CcTest::InitializeVM();
    Heap* heap = CcTest::heap();
    Isolate* isolate = CcTest::i_isolate();
    HandleScope handle_scope(isolate);
  
    // Used to ensure that the generated code is not collected.
    const int kInitialSize = 32;
    Handle<FixedArray> array = isolate->factory()->NewFixedArray(kInitialSize);
  
    // Ensure that all immovable code space pages are full and we overflow into
    // LO_SPACE.
    const int kMaxIterations = 1 << 16;
    bool overflowed_into_lospace = false;
    for (int i = 0; i < kMaxIterations; i++) {
      Handle<Code> code = GenerateDummyImmovableCode(isolate);
      array = FixedArray::SetAndGrow(isolate, array, i, code);
      CHECK(heap->code_space()->Contains(code->address()) ||
            heap->code_lo_space()->Contains(*code));
      if (heap->code_lo_space()->Contains(*code)) {
        overflowed_into_lospace = true;
        break;
      }
    }
  
    CHECK(overflowed_into_lospace);
  
    // Fake a serializer run.
    isolate->serializer_enabled_ = true;
  
    // Generate the code.
    Handle<Code> code = GenerateDummyImmovableCode(isolate);
    CHECK_GE(i::kMaxRegularHeapObjectSize, code->Size());
    CHECK(!heap->code_space()->first_page()->Contains(code->address()));
  
    // Ensure it's not in large object space.
    MemoryChunk* chunk = MemoryChunk::FromHeapObject(*code);
    CHECK(chunk->owner_identity() != LO_SPACE);
    CHECK(chunk->NeverEvacuate());
  }
  
  TEST(Regress6800) {
    CcTest::InitializeVM();
    Isolate* isolate = CcTest::i_isolate();
    HandleScope handle_scope(isolate);
  
    const int kRootLength = 1000;
    Handle<FixedArray> root =
        isolate->factory()->NewFixedArray(kRootLength, AllocationType::kOld);
    {
      HandleScope inner_scope(isolate);
      Handle<FixedArray> new_space_array = isolate->factory()->NewFixedArray(1);
      for (int i = 0; i < kRootLength; i++) {
        root->set(i, *new_space_array);
      }
      for (int i = 0; i < kRootLength; i++) {
        root->set(i, ReadOnlyRoots(CcTest::heap()).undefined_value());
      }
    }
    CcTest::CollectGarbage(NEW_SPACE);
    CHECK_EQ(0, RememberedSet<OLD_TO_NEW>::NumberOfPreFreedEmptyBuckets(
                    MemoryChunk::FromHeapObject(*root)));
  }
  
  TEST(Regress6800LargeObject) {
    CcTest::InitializeVM();
    Isolate* isolate = CcTest::i_isolate();
    HandleScope handle_scope(isolate);
  
    const int kRootLength = i::kMaxRegularHeapObjectSize / kTaggedSize;
    Handle<FixedArray> root =
        isolate->factory()->NewFixedArray(kRootLength, AllocationType::kOld);
    CcTest::heap()->lo_space()->Contains(*root);
    {
      HandleScope inner_scope(isolate);
      Handle<FixedArray> new_space_array = isolate->factory()->NewFixedArray(1);
      for (int i = 0; i < kRootLength; i++) {
        root->set(i, *new_space_array);
      }
      for (int i = 0; i < kRootLength; i++) {
        root->set(i, ReadOnlyRoots(CcTest::heap()).undefined_value());
      }
    }
    CcTest::CollectGarbage(OLD_SPACE);
    CHECK_EQ(0, RememberedSet<OLD_TO_NEW>::NumberOfPreFreedEmptyBuckets(
                    MemoryChunk::FromHeapObject(*root)));
  }
  
  HEAP_TEST(RegressMissingWriteBarrierInAllocate) {
    if (!FLAG_incremental_marking) return;
    ManualGCScope manual_gc_scope;
    CcTest::InitializeVM();
    v8::HandleScope scope(CcTest::isolate());
    Heap* heap = CcTest::heap();
    Isolate* isolate = heap->isolate();
    CcTest::CollectAllGarbage();
    heap::SimulateIncrementalMarking(heap, false);
    Handle<Map> map;
    {
      AlwaysAllocateScope always_allocate(isolate);
      map = isolate->factory()->NewMap(HEAP_NUMBER_TYPE, HeapNumber::kSize);
    }
    heap->incremental_marking()->StartBlackAllocationForTesting();
    Handle<HeapObject> object;
    {
      AlwaysAllocateScope always_allocate(isolate);
      object = handle(isolate->factory()->NewForTest(map, AllocationType::kOld),
                      isolate);
    }
    // The object is black. If Factory::New sets the map without write-barrier,
    // then the map is white and will be freed prematurely.
    heap::SimulateIncrementalMarking(heap, true);
    CcTest::CollectAllGarbage();
    MarkCompactCollector* collector = heap->mark_compact_collector();
    if (collector->sweeping_in_progress()) {
      collector->EnsureSweepingCompleted();
    }
    CHECK(object->map().IsMap());
  }
  
  HEAP_TEST(MarkCompactEpochCounter) {
    ManualGCScope manual_gc_scope;
    CcTest::InitializeVM();
    v8::HandleScope scope(CcTest::isolate());
    Heap* heap = CcTest::heap();
    unsigned epoch0 = heap->mark_compact_collector()->epoch();
    CcTest::CollectGarbage(OLD_SPACE);
    unsigned epoch1 = heap->mark_compact_collector()->epoch();
    CHECK_EQ(epoch0 + 1, epoch1);
    heap::SimulateIncrementalMarking(heap, true);
    CcTest::CollectGarbage(OLD_SPACE);
    unsigned epoch2 = heap->mark_compact_collector()->epoch();
    CHECK_EQ(epoch1 + 1, epoch2);
    CcTest::CollectGarbage(NEW_SPACE);
    unsigned epoch3 = heap->mark_compact_collector()->epoch();
    CHECK_EQ(epoch2, epoch3);
  }
  
  UNINITIALIZED_TEST(ReinitializeStringHashSeed) {
    // Enable rehashing and create an isolate and context.
    i::FLAG_rehash_snapshot = true;
    for (int i = 1; i < 3; i++) {
      i::FLAG_hash_seed = 1337 * i;
      v8::Isolate::CreateParams create_params;
      create_params.array_buffer_allocator = CcTest::array_buffer_allocator();
      v8::Isolate* isolate = v8::Isolate::New(create_params);
      {
        v8::Isolate::Scope isolate_scope(isolate);
        CHECK_EQ(static_cast<uint64_t>(1337 * i),
                 HashSeed(reinterpret_cast<i::Isolate*>(isolate)));
        v8::HandleScope handle_scope(isolate);
        v8::Local<v8::Context> context = v8::Context::New(isolate);
        CHECK(!context.IsEmpty());
        v8::Context::Scope context_scope(context);
      }
      isolate->Dispose();
      ReadOnlyHeap::ClearSharedHeapForTest();
    }
  }
  
  const int kHeapLimit = 100 * MB;
  Isolate* oom_isolate = nullptr;
  
  void OOMCallback(const char* location, bool is_heap_oom) {
    Heap* heap = oom_isolate->heap();
    size_t kSlack = heap->new_space()->Capacity();
    CHECK_LE(heap->OldGenerationCapacity(), kHeapLimit + kSlack);
    CHECK_LE(heap->memory_allocator()->Size(), heap->MaxReserved() + kSlack);
    base::OS::ExitProcess(0);
  }
  
  UNINITIALIZED_TEST(OutOfMemory) {
    if (FLAG_stress_incremental_marking) return;
  #ifdef VERIFY_HEAP
    if (FLAG_verify_heap) return;
  #endif
    FLAG_max_old_space_size = kHeapLimit / MB;
    v8::Isolate::CreateParams create_params;
    create_params.array_buffer_allocator = CcTest::array_buffer_allocator();
    v8::Isolate* isolate = v8::Isolate::New(create_params);
    Isolate* i_isolate = reinterpret_cast<Isolate*>(isolate);
    oom_isolate = i_isolate;
    isolate->SetOOMErrorHandler(OOMCallback);
    {
      Factory* factory = i_isolate->factory();
      HandleScope handle_scope(i_isolate);
      while (true) {
        factory->NewFixedArray(100);
      }
    }
  }
  
  UNINITIALIZED_TEST(OutOfMemoryIneffectiveGC) {
    if (!FLAG_detect_ineffective_gcs_near_heap_limit) return;
    if (FLAG_stress_incremental_marking) return;
  #ifdef VERIFY_HEAP
    if (FLAG_verify_heap) return;
  #endif
  
    FLAG_max_old_space_size = kHeapLimit / MB;
    v8::Isolate::CreateParams create_params;
    create_params.array_buffer_allocator = CcTest::array_buffer_allocator();
    v8::Isolate* isolate = v8::Isolate::New(create_params);
    Isolate* i_isolate = reinterpret_cast<Isolate*>(isolate);
    oom_isolate = i_isolate;
    isolate->SetOOMErrorHandler(OOMCallback);
    Factory* factory = i_isolate->factory();
    Heap* heap = i_isolate->heap();
    heap->CollectAllGarbage(Heap::kNoGCFlags, GarbageCollectionReason::kTesting);
    {
      HandleScope scope(i_isolate);
      while (heap->OldGenerationSizeOfObjects() <
             heap->MaxOldGenerationSize() * 0.9) {
        factory->NewFixedArray(100, AllocationType::kOld);
      }
      {
        int initial_ms_count = heap->ms_count();
        int ineffective_ms_start = initial_ms_count;
        while (heap->ms_count() < initial_ms_count + 10) {
          HandleScope inner_scope(i_isolate);
          factory->NewFixedArray(30000, AllocationType::kOld);
          if (heap->tracer()->AverageMarkCompactMutatorUtilization() >= 0.3) {
            ineffective_ms_start = heap->ms_count() + 1;
          }
        }
        int consecutive_ineffective_ms = heap->ms_count() - ineffective_ms_start;
        CHECK_IMPLIES(
            consecutive_ineffective_ms >= 4,
            heap->tracer()->AverageMarkCompactMutatorUtilization() >= 0.3);
      }
    }
    isolate->Dispose();
  }
  
  HEAP_TEST(Regress779503) {
    // The following regression test ensures that the Scavenger does not allocate
    // over invalid slots. More specific, the Scavenger should not sweep a page
    // that it currently processes because it might allocate over the currently
    // processed slot.
    const int kArraySize = 2048;
    CcTest::InitializeVM();
    Isolate* isolate = CcTest::i_isolate();
    Heap* heap = CcTest::heap();
    heap::SealCurrentObjects(heap);
    {
      HandleScope handle_scope(isolate);
      // The byte array filled with kHeapObjectTag ensures that we cannot read
      // from the slot again and interpret it as heap value. Doing so will crash.
      Handle<ByteArray> byte_array = isolate->factory()->NewByteArray(kArraySize);
      CHECK(Heap::InYoungGeneration(*byte_array));
      for (int i = 0; i < kArraySize; i++) {
        byte_array->set(i, kHeapObjectTag);
      }
  
      {
        HandleScope handle_scope(isolate);
        // The FixedArray in old space serves as space for slots.
        Handle<FixedArray> fixed_array =
            isolate->factory()->NewFixedArray(kArraySize, AllocationType::kOld);
        CHECK(!Heap::InYoungGeneration(*fixed_array));
        for (int i = 0; i < kArraySize; i++) {
          fixed_array->set(i, *byte_array);
        }
      }
      // Delay sweeper tasks to allow the scavenger to sweep the page it is
      // currently scavenging.
      heap->delay_sweeper_tasks_for_testing_ = true;
      CcTest::CollectGarbage(OLD_SPACE);
      CHECK(Heap::InYoungGeneration(*byte_array));
    }
    // Scavenging and sweeping the same page will crash as slots will be
    // overridden.
    CcTest::CollectGarbage(NEW_SPACE);
    heap->delay_sweeper_tasks_for_testing_ = false;
  }
  
  struct OutOfMemoryState {
    Heap* heap;
    bool oom_triggered;
    size_t old_generation_capacity_at_oom;
    size_t memory_allocator_size_at_oom;
    size_t new_space_capacity_at_oom;
    size_t new_lo_space_size_at_oom;
    size_t current_heap_limit;
    size_t initial_heap_limit;
  };
  
  size_t NearHeapLimitCallback(void* raw_state, size_t current_heap_limit,
                               size_t initial_heap_limit) {
    OutOfMemoryState* state = static_cast<OutOfMemoryState*>(raw_state);
    Heap* heap = state->heap;
    state->oom_triggered = true;
    state->old_generation_capacity_at_oom = heap->OldGenerationCapacity();
    state->memory_allocator_size_at_oom = heap->memory_allocator()->Size();
    state->new_space_capacity_at_oom = heap->new_space()->Capacity();
    state->new_lo_space_size_at_oom = heap->new_lo_space()->Size();
    state->current_heap_limit = current_heap_limit;
    state->initial_heap_limit = initial_heap_limit;
    return initial_heap_limit + 100 * MB;
  }
  
  size_t MemoryAllocatorSizeFromHeapCapacity(size_t capacity) {
    // Size to capacity factor.
    double factor =
        Page::kPageSize * 1.0 / MemoryChunkLayout::AllocatableMemoryInDataPage();
    // Some tables (e.g. deoptimization table) are allocated directly with the
    // memory allocator. Allow some slack to account for them.
    size_t slack = 5 * MB;
    return static_cast<size_t>(capacity * factor) + slack;
  }
  
  UNINITIALIZED_TEST(OutOfMemorySmallObjects) {
    if (FLAG_stress_incremental_marking) return;
  #ifdef VERIFY_HEAP
    if (FLAG_verify_heap) return;
  #endif
    const size_t kOldGenerationLimit = 300 * MB;
    FLAG_max_old_space_size = kOldGenerationLimit / MB;
    v8::Isolate::CreateParams create_params;
    create_params.array_buffer_allocator = CcTest::array_buffer_allocator();
    Isolate* isolate =
        reinterpret_cast<Isolate*>(v8::Isolate::New(create_params));
    Heap* heap = isolate->heap();
    Factory* factory = isolate->factory();
    OutOfMemoryState state;
    state.heap = heap;
    state.oom_triggered = false;
    heap->AddNearHeapLimitCallback(NearHeapLimitCallback, &state);
    {
      HandleScope handle_scope(isolate);
      while (!state.oom_triggered) {
        factory->NewFixedArray(100);
      }
    }
    CHECK_LE(state.old_generation_capacity_at_oom,
             kOldGenerationLimit + state.new_space_capacity_at_oom);
    CHECK_LE(kOldGenerationLimit, state.old_generation_capacity_at_oom +
                                      state.new_space_capacity_at_oom);
    CHECK_LE(
        state.memory_allocator_size_at_oom,
        MemoryAllocatorSizeFromHeapCapacity(state.old_generation_capacity_at_oom +
                                            2 * state.new_space_capacity_at_oom));
    reinterpret_cast<v8::Isolate*>(isolate)->Dispose();
  }
  
  UNINITIALIZED_TEST(OutOfMemoryLargeObjects) {
    if (FLAG_stress_incremental_marking) return;
  #ifdef VERIFY_HEAP
    if (FLAG_verify_heap) return;
  #endif
    const size_t kOldGenerationLimit = 300 * MB;
    FLAG_max_old_space_size = kOldGenerationLimit / MB;
    v8::Isolate::CreateParams create_params;
    create_params.array_buffer_allocator = CcTest::array_buffer_allocator();
    Isolate* isolate =
        reinterpret_cast<Isolate*>(v8::Isolate::New(create_params));
    Heap* heap = isolate->heap();
    Factory* factory = isolate->factory();
    OutOfMemoryState state;
    state.heap = heap;
    state.oom_triggered = false;
    heap->AddNearHeapLimitCallback(NearHeapLimitCallback, &state);
    const int kFixedArrayLength = 1000000;
    {
      HandleScope handle_scope(isolate);
      while (!state.oom_triggered) {
        factory->NewFixedArray(kFixedArrayLength);
      }
    }
    CHECK_LE(state.old_generation_capacity_at_oom, kOldGenerationLimit);
    size_t size = std::max(state.old_generation_capacity_at_oom,
                           state.memory_allocator_size_at_oom);
    CHECK_LE(kOldGenerationLimit, size + state.new_space_capacity_at_oom +
                                      state.new_lo_space_size_at_oom +
                                      FixedArray::SizeFor(kFixedArrayLength));
    CHECK_LE(
        state.memory_allocator_size_at_oom,
        MemoryAllocatorSizeFromHeapCapacity(state.old_generation_capacity_at_oom +
                                            2 * state.new_space_capacity_at_oom +
                                            state.new_lo_space_size_at_oom));
    reinterpret_cast<v8::Isolate*>(isolate)->Dispose();
  }
  
  UNINITIALIZED_TEST(RestoreHeapLimit) {
    if (FLAG_stress_incremental_marking) return;
  #ifdef VERIFY_HEAP
    if (FLAG_verify_heap) return;
  #endif
    ManualGCScope manual_gc_scope;
    const size_t kOldGenerationLimit = 300 * MB;
    FLAG_max_old_space_size = kOldGenerationLimit / MB;
    v8::Isolate::CreateParams create_params;
    create_params.array_buffer_allocator = CcTest::array_buffer_allocator();
    Isolate* isolate =
        reinterpret_cast<Isolate*>(v8::Isolate::New(create_params));
    Heap* heap = isolate->heap();
    Factory* factory = isolate->factory();
    OutOfMemoryState state;
    state.heap = heap;
    state.oom_triggered = false;
    heap->AddNearHeapLimitCallback(NearHeapLimitCallback, &state);
    heap->AutomaticallyRestoreInitialHeapLimit(0.5);
    const int kFixedArrayLength = 1000000;
    {
      HandleScope handle_scope(isolate);
      while (!state.oom_triggered) {
        factory->NewFixedArray(kFixedArrayLength);
      }
    }
    heap->MemoryPressureNotification(MemoryPressureLevel::kCritical, true);
    state.oom_triggered = false;
    {
      HandleScope handle_scope(isolate);
      while (!state.oom_triggered) {
        factory->NewFixedArray(kFixedArrayLength);
      }
    }
    CHECK_EQ(state.current_heap_limit, state.initial_heap_limit);
    reinterpret_cast<v8::Isolate*>(isolate)->Dispose();
  }
  
  void HeapTester::UncommitFromSpace(Heap* heap) {
    heap->UncommitFromSpace();
    heap->memory_allocator()->unmapper()->EnsureUnmappingCompleted();
  }
  
  class DeleteNative {
   public:
    static void Deleter(void* arg) {
      delete reinterpret_cast<DeleteNative*>(arg);
    }
  };
  
  TEST(Regress8014) {
    Isolate* isolate = CcTest::InitIsolateOnce();
    Heap* heap = isolate->heap();
    {
      HandleScope scope(isolate);
      for (int i = 0; i < 10000; i++) {
        auto handle = Managed<DeleteNative>::FromRawPtr(isolate, 1000000,
                                                        new DeleteNative());
        USE(handle);
      }
    }
    int ms_count = heap->ms_count();
    heap->MemoryPressureNotification(MemoryPressureLevel::kCritical, true);
    // Several GCs can be triggred by the above call.
    // The bad case triggers 10000 GCs.
    CHECK_LE(heap->ms_count(), ms_count + 10);
  }
  
  TEST(Regress8617) {
    ManualGCScope manual_gc_scope;
    FLAG_manual_evacuation_candidates_selection = true;
    LocalContext env;
    Isolate* isolate = CcTest::i_isolate();
    Heap* heap = isolate->heap();
    HandleScope scope(isolate);
    heap::SimulateFullSpace(heap->old_space());
    // Step 1. Create a function and ensure that it is in the old space.
    Handle<Object> foo =
        v8::Utils::OpenHandle(*CompileRun("function foo() { return 42; };"
                                          "foo;"));
    if (heap->InYoungGeneration(*foo)) {
      CcTest::CollectGarbage(NEW_SPACE);
      CcTest::CollectGarbage(NEW_SPACE);
    }
    // Step 2. Create an object with a reference to foo in the descriptor array.
    CompileRun(
        "var obj = {};"
        "obj.method = foo;"
        "obj;");
    // Step 3. Make sure that foo moves during Mark-Compact.
    Page* ec_page = Page::FromAddress(foo->ptr());
    heap::ForceEvacuationCandidate(ec_page);
    // Step 4. Start incremental marking.
    heap::SimulateIncrementalMarking(heap, false);
    CHECK(ec_page->IsEvacuationCandidate());
    // Step 5. Install a new descriptor array on the map of the object.
    // This runs the marking barrier for the descriptor array.
    // In the bad case it sets the number of marked descriptors but does not
    // change the color of the descriptor array.
    CompileRun("obj.bar = 10;");
    // Step 6. Promote the descriptor array to old space. During promotion
    // the Scavenger will not record the slot of foo in the descriptor array.
    CcTest::CollectGarbage(NEW_SPACE);
    CcTest::CollectGarbage(NEW_SPACE);
    // Step 7. Complete the Mark-Compact.
    CcTest::CollectAllGarbage();
    // Step 8. Use the descriptor for foo, which contains a stale pointer.
    CompileRun("obj.method()");
  }
  
  HEAP_TEST(MemoryReducerActivationForSmallHeaps) {
    ManualGCScope manual_gc_scope;
    LocalContext env;
    Isolate* isolate = CcTest::i_isolate();
    Heap* heap = isolate->heap();
    CHECK_EQ(heap->memory_reducer()->state_.action, MemoryReducer::Action::kDone);
    HandleScope scope(isolate);
    const size_t kActivationThreshold = 1 * MB;
    size_t initial_capacity = heap->OldGenerationCapacity();
    while (heap->OldGenerationCapacity() <
           initial_capacity + kActivationThreshold) {
      isolate->factory()->NewFixedArray(1 * KB, AllocationType::kOld);
    }
    CHECK_EQ(heap->memory_reducer()->state_.action, MemoryReducer::Action::kWait);
  }
  
  TEST(CodeObjectRegistry) {
    // We turn off compaction to ensure that code is not moving.
    FLAG_never_compact = true;
  
    Isolate* isolate = CcTest::i_isolate();
    Heap* heap = isolate->heap();
  
    Handle<Code> code1;
    HandleScope outer_scope(heap->isolate());
    Address code2_address;
    {
      code1 = DummyOptimizedCode(isolate);
      Handle<Code> code2 = DummyOptimizedCode(isolate);
      code2_address = code2->address();
      // If this check breaks, change the allocation to ensure that both code
      // objects are on the same page.
      CHECK_EQ(MemoryChunk::FromHeapObject(*code1),
               MemoryChunk::FromHeapObject(*code2));
      CHECK(MemoryChunk::FromHeapObject(*code1)->Contains(code1->address()));
      CHECK(MemoryChunk::FromHeapObject(*code2)->Contains(code2->address()));
    }
    CcTest::CollectAllAvailableGarbage();
    CHECK(MemoryChunk::FromHeapObject(*code1)->Contains(code1->address()));
    CHECK(MemoryChunk::FromAddress(code2_address)->Contains(code2_address));
  }
  
  }  // namespace heap
  }  // namespace internal
  }  // namespace v8
  
  #undef __
  