text: // Copyright 2014 the V8 project authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  
  #include "src/factory.h"
  
  #include "src/allocation-site-scopes.h"
  #include "src/conversions.h"
  #include "src/isolate-inl.h"
  #include "src/macro-assembler.h"
  
  namespace v8 {
  namespace internal {
  
  
  template<typename T>
  Handle<T> Factory::New(Handle<Map> map, AllocationSpace space) {
    CALL_HEAP_FUNCTION(
        isolate(),
        isolate()->heap()->Allocate(*map, space),
        T);
  }
  
  
  template<typename T>
  Handle<T> Factory::New(Handle<Map> map,
                         AllocationSpace space,
                         Handle<AllocationSite> allocation_site) {
    CALL_HEAP_FUNCTION(
        isolate(),
        isolate()->heap()->Allocate(*map, space, *allocation_site),
        T);
  }
  
  
  Handle<HeapObject> Factory::NewFillerObject(int size,
                                              bool double_align,
                                              AllocationSpace space) {
    CALL_HEAP_FUNCTION(
        isolate(),
        isolate()->heap()->AllocateFillerObject(size, double_align, space),
        HeapObject);
  }
  
  
  Handle<Box> Factory::NewBox(Handle<Object> value) {
    Handle<Box> result = Handle<Box>::cast(NewStruct(BOX_TYPE));
    result->set_value(*value);
    return result;
  }
  
  
  Handle<Oddball> Factory::NewOddball(Handle<Map> map,
                                      const char* to_string,
                                      Handle<Object> to_number,
                                      byte kind) {
    Handle<Oddball> oddball = New<Oddball>(map, OLD_POINTER_SPACE);
    Oddball::Initialize(isolate(), oddball, to_string, to_number, kind);
    return oddball;
  }
  
  
  Handle<FixedArray> Factory::NewFixedArray(int size, PretenureFlag pretenure) {
    DCHECK(0 <= size);
    CALL_HEAP_FUNCTION(
        isolate(),
        isolate()->heap()->AllocateFixedArray(size, pretenure),
        FixedArray);
  }
  
  
  Handle<FixedArray> Factory::NewFixedArrayWithHoles(int size,
                                                     PretenureFlag pretenure) {
    DCHECK(0 <= size);
    CALL_HEAP_FUNCTION(
        isolate(),
        isolate()->heap()->AllocateFixedArrayWithFiller(size,
                                                        pretenure,
                                                        *the_hole_value()),
        FixedArray);
  }
  
  
  Handle<FixedArray> Factory::NewUninitializedFixedArray(int size) {
    CALL_HEAP_FUNCTION(
        isolate(),
        isolate()->heap()->AllocateUninitializedFixedArray(size),
        FixedArray);
  }
  
  
  Handle<FixedArrayBase> Factory::NewFixedDoubleArray(int size,
                                                      PretenureFlag pretenure) {
    DCHECK(0 <= size);
    CALL_HEAP_FUNCTION(
        isolate(),
        isolate()->heap()->AllocateUninitializedFixedDoubleArray(size, pretenure),
        FixedArrayBase);
  }
  
  
  Handle<FixedArrayBase> Factory::NewFixedDoubleArrayWithHoles(
      int size,
      PretenureFlag pretenure) {
    DCHECK(0 <= size);
    Handle<FixedArrayBase> array = NewFixedDoubleArray(size, pretenure);
    if (size > 0) {
      Handle<FixedDoubleArray> double_array =
          Handle<FixedDoubleArray>::cast(array);
      for (int i = 0; i < size; ++i) {
        double_array->set_the_hole(i);
      }
    }
    return array;
  }
  
  
  Handle<ConstantPoolArray> Factory::NewConstantPoolArray(
      const ConstantPoolArray::NumberOfEntries& small) {
    DCHECK(small.total_count() > 0);
    CALL_HEAP_FUNCTION(
        isolate(),
        isolate()->heap()->AllocateConstantPoolArray(small),
        ConstantPoolArray);
  }
  
  
  Handle<ConstantPoolArray> Factory::NewExtendedConstantPoolArray(
      const ConstantPoolArray::NumberOfEntries& small,
      const ConstantPoolArray::NumberOfEntries& extended) {
    DCHECK(small.total_count() > 0);
    DCHECK(extended.total_count() > 0);
    CALL_HEAP_FUNCTION(
        isolate(),
        isolate()->heap()->AllocateExtendedConstantPoolArray(small, extended),
        ConstantPoolArray);
  }
  
  
  Handle<OrderedHashSet> Factory::NewOrderedHashSet() {
    return OrderedHashSet::Allocate(isolate(), 4);
  }
  
  
  Handle<OrderedHashMap> Factory::NewOrderedHashMap() {
    return OrderedHashMap::Allocate(isolate(), 4);
  }
  
  
  Handle<AccessorPair> Factory::NewAccessorPair() {
    Handle<AccessorPair> accessors =
        Handle<AccessorPair>::cast(NewStruct(ACCESSOR_PAIR_TYPE));
    accessors->set_getter(*the_hole_value(), SKIP_WRITE_BARRIER);
    accessors->set_setter(*the_hole_value(), SKIP_WRITE_BARRIER);
    return accessors;
  }
  
  
  Handle<TypeFeedbackInfo> Factory::NewTypeFeedbackInfo() {
    Handle<TypeFeedbackInfo> info =
        Handle<TypeFeedbackInfo>::cast(NewStruct(TYPE_FEEDBACK_INFO_TYPE));
    info->initialize_storage();
    return info;
  }
  
  
  // Internalized strings are created in the old generation (data space).
  Handle<String> Factory::InternalizeUtf8String(Vector<const char> string) {
    Utf8StringKey key(string, isolate()->heap()->HashSeed());
    return InternalizeStringWithKey(&key);
  }
  
  
  // Internalized strings are created in the old generation (data space).
  Handle<String> Factory::InternalizeString(Handle<String> string) {
    if (string->IsInternalizedString()) return string;
    return StringTable::LookupString(isolate(), string);
  }
  
  
  Handle<String> Factory::InternalizeOneByteString(Vector<const uint8_t> string) {
    OneByteStringKey key(string, isolate()->heap()->HashSeed());
    return InternalizeStringWithKey(&key);
  }
  
  
  Handle<String> Factory::InternalizeOneByteString(
      Handle<SeqOneByteString> string, int from, int length) {
    SubStringKey<uint8_t> key(string, from, length);
    return InternalizeStringWithKey(&key);
  }
  
  
  Handle<String> Factory::InternalizeTwoByteString(Vector<const uc16> string) {
    TwoByteStringKey key(string, isolate()->heap()->HashSeed());
    return InternalizeStringWithKey(&key);
  }
  
  
  template<class StringTableKey>
  Handle<String> Factory::InternalizeStringWithKey(StringTableKey* key) {
    return StringTable::LookupKey(isolate(), key);
  }
  
  
  template Handle<String> Factory::InternalizeStringWithKey<
      SubStringKey<uint8_t> > (SubStringKey<uint8_t>* key);
  template Handle<String> Factory::InternalizeStringWithKey<
      SubStringKey<uint16_t> > (SubStringKey<uint16_t>* key);
  
  
  MaybeHandle<String> Factory::NewStringFromOneByte(Vector<const uint8_t> string,
                                                    PretenureFlag pretenure) {
    int length = string.length();
    if (length == 1) return LookupSingleCharacterStringFromCode(string[0]);
    Handle<SeqOneByteString> result;
    ASSIGN_RETURN_ON_EXCEPTION(
        isolate(),
        result,
        NewRawOneByteString(string.length(), pretenure),
        String);
  
    DisallowHeapAllocation no_gc;
    // Copy the characters into the new object.
    CopyChars(SeqOneByteString::cast(*result)->GetChars(),
              string.start(),
              length);
    return result;
  }
  
  MaybeHandle<String> Factory::NewStringFromUtf8(Vector<const char> string,
                                                 PretenureFlag pretenure) {
    // Check for ASCII first since this is the common case.
    const char* start = string.start();
    int length = string.length();
    int non_ascii_start = String::NonAsciiStart(start, length);
    if (non_ascii_start >= length) {
      // If the string is ASCII, we do not need to convert the characters
      // since UTF8 is backwards compatible with ASCII.
      return NewStringFromOneByte(Vector<const uint8_t>::cast(string), pretenure);
    }
  
    // Non-ASCII and we need to decode.
    Access<UnicodeCache::Utf8Decoder>
        decoder(isolate()->unicode_cache()->utf8_decoder());
    decoder->Reset(string.start() + non_ascii_start,
                   length - non_ascii_start);
    int utf16_length = decoder->Utf16Length();
    DCHECK(utf16_length > 0);
    // Allocate string.
    Handle<SeqTwoByteString> result;
    ASSIGN_RETURN_ON_EXCEPTION(
        isolate(), result,
        NewRawTwoByteString(non_ascii_start + utf16_length, pretenure),
        String);
    // Copy ascii portion.
    uint16_t* data = result->GetChars();
    const char* ascii_data = string.start();
    for (int i = 0; i < non_ascii_start; i++) {
      *data++ = *ascii_data++;
    }
    // Now write the remainder.
    decoder->WriteUtf16(data, utf16_length);
    return result;
  }
  
  
  MaybeHandle<String> Factory::NewStringFromTwoByte(Vector<const uc16> string,
                                                    PretenureFlag pretenure) {
    int length = string.length();
    const uc16* start = string.start();
    if (String::IsOneByte(start, length)) {
      if (length == 1) return LookupSingleCharacterStringFromCode(string[0]);
      Handle<SeqOneByteString> result;
      ASSIGN_RETURN_ON_EXCEPTION(
          isolate(),
          result,
          NewRawOneByteString(length, pretenure),
          String);
      CopyChars(result->GetChars(), start, length);
      return result;
    } else {
      Handle<SeqTwoByteString> result;
      ASSIGN_RETURN_ON_EXCEPTION(
          isolate(),
          result,
          NewRawTwoByteString(length, pretenure),
          String);
      CopyChars(result->GetChars(), start, length);
      return result;
    }
  }
  
  
  Handle<String> Factory::NewInternalizedStringFromUtf8(Vector<const char> str,
                                                        int chars,
                                                        uint32_t hash_field) {
    CALL_HEAP_FUNCTION(
        isolate(),
        isolate()->heap()->AllocateInternalizedStringFromUtf8(
            str, chars, hash_field),
        String);
  }
  
  
  MUST_USE_RESULT Handle<String> Factory::NewOneByteInternalizedString(
        Vector<const uint8_t> str,
        uint32_t hash_field) {
    CALL_HEAP_FUNCTION(
        isolate(),
        isolate()->heap()->AllocateOneByteInternalizedString(str, hash_field),
        String);
  }
  
  
  MUST_USE_RESULT Handle<String> Factory::NewTwoByteInternalizedString(
        Vector<const uc16> str,
        uint32_t hash_field) {
    CALL_HEAP_FUNCTION(
        isolate(),
        isolate()->heap()->AllocateTwoByteInternalizedString(str, hash_field),
        String);
  }
  
  
  Handle<String> Factory::NewInternalizedStringImpl(
      Handle<String> string, int chars, uint32_t hash_field) {
    CALL_HEAP_FUNCTION(
        isolate(),
        isolate()->heap()->AllocateInternalizedStringImpl(
            *string, chars, hash_field),
        String);
  }
  
  
  MaybeHandle<Map> Factory::InternalizedStringMapForString(
      Handle<String> string) {
    // If the string is in new space it cannot be used as internalized.
    if (isolate()->heap()->InNewSpace(*string)) return MaybeHandle<Map>();
  
    // Find the corresponding internalized string map for strings.
    switch (string->map()->instance_type()) {
      case STRING_TYPE: return internalized_string_map();
      case ASCII_STRING_TYPE: return ascii_internalized_string_map();
      case EXTERNAL_STRING_TYPE: return external_internalized_string_map();
      case EXTERNAL_ASCII_STRING_TYPE:
        return external_ascii_internalized_string_map();
      case EXTERNAL_STRING_WITH_ONE_BYTE_DATA_TYPE:
        return external_internalized_string_with_one_byte_data_map();
      case SHORT_EXTERNAL_STRING_TYPE:
        return short_external_internalized_string_map();
      case SHORT_EXTERNAL_ASCII_STRING_TYPE:
        return short_external_ascii_internalized_string_map();
      case SHORT_EXTERNAL_STRING_WITH_ONE_BYTE_DATA_TYPE:
        return short_external_internalized_string_with_one_byte_data_map();
      default: return MaybeHandle<Map>();  // No match found.
    }
  }
  
  
  MaybeHandle<SeqOneByteString> Factory::NewRawOneByteString(
      int length, PretenureFlag pretenure) {
    if (length > String::kMaxLength || length < 0) {
      return isolate()->Throw<SeqOneByteString>(NewInvalidStringLengthError());
    }
    CALL_HEAP_FUNCTION(
        isolate(),
        isolate()->heap()->AllocateRawOneByteString(length, pretenure),
        SeqOneByteString);
  }
  
  
  MaybeHandle<SeqTwoByteString> Factory::NewRawTwoByteString(
      int length, PretenureFlag pretenure) {
    if (length > String::kMaxLength || length < 0) {
      return isolate()->Throw<SeqTwoByteString>(NewInvalidStringLengthError());
    }
    CALL_HEAP_FUNCTION(
        isolate(),
        isolate()->heap()->AllocateRawTwoByteString(length, pretenure),
        SeqTwoByteString);
  }
  
  
  Handle<String> Factory::LookupSingleCharacterStringFromCode(uint32_t code) {
    if (code <= String::kMaxOneByteCharCodeU) {
      {
        DisallowHeapAllocation no_allocation;
        Object* value = single_character_string_cache()->get(code);
        if (value != *undefined_value()) {
          return handle(String::cast(value), isolate());
        }
      }
      uint8_t buffer[1];
      buffer[0] = static_cast<uint8_t>(code);
      Handle<String> result =
          InternalizeOneByteString(Vector<const uint8_t>(buffer, 1));
      single_character_string_cache()->set(code, *result);
      return result;
    }
    DCHECK(code <= String::kMaxUtf16CodeUnitU);
  
    Handle<SeqTwoByteString> result = NewRawTwoByteString(1).ToHandleChecked();
    result->SeqTwoByteStringSet(0, static_cast<uint16_t>(code));
    return result;
  }
  
  
  // Returns true for a character in a range.  Both limits are inclusive.
  static inline bool Between(uint32_t character, uint32_t from, uint32_t to) {
    // This makes uses of the the unsigned wraparound.
    return character - from <= to - from;
  }
  
  
  static inline Handle<String> MakeOrFindTwoCharacterString(Isolate* isolate,
                                                            uint16_t c1,
                                                            uint16_t c2) {
    // Numeric strings have a different hash algorithm not known by
    // LookupTwoCharsStringIfExists, so we skip this step for such strings.
    if (!Between(c1, '0', '9') || !Between(c2, '0', '9')) {
      Handle<String> result;
      if (StringTable::LookupTwoCharsStringIfExists(isolate, c1, c2).
          ToHandle(&result)) {
        return result;
      }
    }
  
    // Now we know the length is 2, we might as well make use of that fact
    // when building the new string.
    if (static_cast<unsigned>(c1 | c2) <= String::kMaxOneByteCharCodeU) {
      // We can do this.
      DCHECK(IsPowerOf2(String::kMaxOneByteCharCodeU + 1));  // because of this.
      Handle<SeqOneByteString> str =
          isolate->factory()->NewRawOneByteString(2).ToHandleChecked();
      uint8_t* dest = str->GetChars();
      dest[0] = static_cast<uint8_t>(c1);
      dest[1] = static_cast<uint8_t>(c2);
      return str;
    } else {
      Handle<SeqTwoByteString> str =
          isolate->factory()->NewRawTwoByteString(2).ToHandleChecked();
      uc16* dest = str->GetChars();
      dest[0] = c1;
      dest[1] = c2;
      return str;
    }
  }
  
  
  template<typename SinkChar, typename StringType>
  Handle<String> ConcatStringContent(Handle<StringType> result,
                                     Handle<String> first,
                                     Handle<String> second) {
    DisallowHeapAllocation pointer_stays_valid;
    SinkChar* sink = result->GetChars();
    String::WriteToFlat(*first, sink, 0, first->length());
    String::WriteToFlat(*second, sink + first->length(), 0, second->length());
    return result;
  }
  
  
  MaybeHandle<String> Factory::NewConsString(Handle<String> left,
                                             Handle<String> right) {
    int left_length = left->length();
    if (left_length == 0) return right;
    int right_length = right->length();
    if (right_length == 0) return left;
  
    int length = left_length + right_length;
  
    if (length == 2) {
      uint16_t c1 = left->Get(0);
      uint16_t c2 = right->Get(0);
      return MakeOrFindTwoCharacterString(isolate(), c1, c2);
    }
  
    // Make sure that an out of memory exception is thrown if the length
    // of the new cons string is too large.
    if (length > String::kMaxLength || length < 0) {
      return isolate()->Throw<String>(NewInvalidStringLengthError());
    }
  
    bool left_is_one_byte = left->IsOneByteRepresentation();
    bool right_is_one_byte = right->IsOneByteRepresentation();
    bool is_one_byte = left_is_one_byte && right_is_one_byte;
    bool is_one_byte_data_in_two_byte_string = false;
    if (!is_one_byte) {
      // At least one of the strings uses two-byte representation so we
      // can't use the fast case code for short ASCII strings below, but
      // we can try to save memory if all chars actually fit in ASCII.
      is_one_byte_data_in_two_byte_string =
          left->HasOnlyOneByteChars() && right->HasOnlyOneByteChars();
      if (is_one_byte_data_in_two_byte_string) {
        isolate()->counters()->string_add_runtime_ext_to_ascii()->Increment();
      }
    }
  
    // If the resulting string is small make a flat string.
    if (length < ConsString::kMinLength) {
      // Note that neither of the two inputs can be a slice because:
      STATIC_ASSERT(ConsString::kMinLength <= SlicedString::kMinLength);
      DCHECK(left->IsFlat());
      DCHECK(right->IsFlat());
  
      STATIC_ASSERT(ConsString::kMinLength <= String::kMaxLength);
      if (is_one_byte) {
        Handle<SeqOneByteString> result =
            NewRawOneByteString(length).ToHandleChecked();
        DisallowHeapAllocation no_gc;
        uint8_t* dest = result->GetChars();
        // Copy left part.
        const uint8_t* src = left->IsExternalString()
            ? Handle<ExternalAsciiString>::cast(left)->GetChars()
            : Handle<SeqOneByteString>::cast(left)->GetChars();
        for (int i = 0; i < left_length; i++) *dest++ = src[i];
        // Copy right part.
        src = right->IsExternalString()
            ? Handle<ExternalAsciiString>::cast(right)->GetChars()
            : Handle<SeqOneByteString>::cast(right)->GetChars();
        for (int i = 0; i < right_length; i++) *dest++ = src[i];
        return result;
      }
  
      return (is_one_byte_data_in_two_byte_string)
          ? ConcatStringContent<uint8_t>(
              NewRawOneByteString(length).ToHandleChecked(), left, right)
          : ConcatStringContent<uc16>(
              NewRawTwoByteString(length).ToHandleChecked(), left, right);
    }
  
    Handle<Map> map = (is_one_byte || is_one_byte_data_in_two_byte_string)
        ? cons_ascii_string_map()  : cons_string_map();
    Handle<ConsString> result =  New<ConsString>(map, NEW_SPACE);
  
    DisallowHeapAllocation no_gc;
    WriteBarrierMode mode = result->GetWriteBarrierMode(no_gc);
  
    result->set_hash_field(String::kEmptyHashField);
    result->set_length(length);
    result->set_first(*left, mode);
    result->set_second(*right, mode);
    return result;
  }
  
  
  Handle<String> Factory::NewProperSubString(Handle<String> str,
                                             int begin,
                                             int end) {
  #if VERIFY_HEAP
    if (FLAG_verify_heap) str->StringVerify();
  #endif
    DCHECK(begin > 0 || end < str->length());
  
    str = String::Flatten(str);
  
    int length = end - begin;
    if (length <= 0) return empty_string();
    if (length == 1) {
      return LookupSingleCharacterStringFromCode(str->Get(begin));
    }
    if (length == 2) {
      // Optimization for 2-byte strings often used as keys in a decompression
      // dictionary.  Check whether we already have the string in the string
      // table to prevent creation of many unnecessary strings.
      uint16_t c1 = str->Get(begin);
      uint16_t c2 = str->Get(begin + 1);
      return MakeOrFindTwoCharacterString(isolate(), c1, c2);
    }
  
    if (!FLAG_string_slices || length < SlicedString::kMinLength) {
      if (str->IsOneByteRepresentation()) {
        Handle<SeqOneByteString> result =
            NewRawOneByteString(length).ToHandleChecked();
        uint8_t* dest = result->GetChars();
        DisallowHeapAllocation no_gc;
        String::WriteToFlat(*str, dest, begin, end);
        return result;
      } else {
        Handle<SeqTwoByteString> result =
            NewRawTwoByteString(length).ToHandleChecked();
        uc16* dest = result->GetChars();
        DisallowHeapAllocation no_gc;
        String::WriteToFlat(*str, dest, begin, end);
        return result;
      }
    }
  
    int offset = begin;
  
    if (str->IsSlicedString()) {
      Handle<SlicedString> slice = Handle<SlicedString>::cast(str);
      str = Handle<String>(slice->parent(), isolate());
      offset += slice->offset();
    }
  
    DCHECK(str->IsSeqString() || str->IsExternalString());
    Handle<Map> map = str->IsOneByteRepresentation() ? sliced_ascii_string_map()
                                                     : sliced_string_map();
    Handle<SlicedString> slice = New<SlicedString>(map, NEW_SPACE);
  
    slice->set_hash_field(String::kEmptyHashField);
    slice->set_length(length);
    slice->set_parent(*str);
    slice->set_offset(offset);
    return slice;
  }
  
  
  MaybeHandle<String> Factory::NewExternalStringFromAscii(
      const ExternalAsciiString::Resource* resource) {
    size_t length = resource->length();
    if (length > static_cast<size_t>(String::kMaxLength)) {
      return isolate()->Throw<String>(NewInvalidStringLengthError());
    }
  
    Handle<Map> map = external_ascii_string_map();
    Handle<ExternalAsciiString> external_string =
        New<ExternalAsciiString>(map, NEW_SPACE);
    external_string->set_length(static_cast<int>(length));
    external_string->set_hash_field(String::kEmptyHashField);
    external_string->set_resource(resource);
  
    return external_string;
  }
  
  
  MaybeHandle<String> Factory::NewExternalStringFromTwoByte(
      const ExternalTwoByteString::Resource* resource) {
    size_t length = resource->length();
    if (length > static_cast<size_t>(String::kMaxLength)) {
      return isolate()->Throw<String>(NewInvalidStringLengthError());
    }
  
    // For small strings we check whether the resource contains only
    // one byte characters.  If yes, we use a different string map.
    static const size_t kOneByteCheckLengthLimit = 32;
    bool is_one_byte = length <= kOneByteCheckLengthLimit &&
        String::IsOneByte(resource->data(), static_cast<int>(length));
    Handle<Map> map = is_one_byte ?
        external_string_with_one_byte_data_map() : external_string_map();
    Handle<ExternalTwoByteString> external_string =
        New<ExternalTwoByteString>(map, NEW_SPACE);
    external_string->set_length(static_cast<int>(length));
    external_string->set_hash_field(String::kEmptyHashField);
    external_string->set_resource(resource);
  
    return external_string;
  }
  
  
  Handle<Symbol> Factory::NewSymbol() {
    CALL_HEAP_FUNCTION(
        isolate(),
        isolate()->heap()->AllocateSymbol(),
        Symbol);
  }
  
  
  Handle<Symbol> Factory::NewPrivateSymbol() {
    Handle<Symbol> symbol = NewSymbol();
    symbol->set_is_private(true);
    return symbol;
  }
  
  
  Handle<Context> Factory::NewNativeContext() {
    Handle<FixedArray> array = NewFixedArray(Context::NATIVE_CONTEXT_SLOTS);
    array->set_map_no_write_barrier(*native_context_map());
    Handle<Context> context = Handle<Context>::cast(array);
    context->set_js_array_maps(*undefined_value());
    DCHECK(context->IsNativeContext());
    return context;
  }
  
  
  Handle<Context> Factory::NewGlobalContext(Handle<JSFunction> function,
                                            Handle<ScopeInfo> scope_info) {
    Handle<FixedArray> array =
        NewFixedArray(scope_info->ContextLength(), TENURED);
    array->set_map_no_write_barrier(*global_context_map());
    Handle<Context> context = Handle<Context>::cast(array);
    context->set_closure(*function);
    context->set_previous(function->context());
    context->set_extension(*scope_info);
    context->set_global_object(function->context()->global_object());
    DCHECK(context->IsGlobalContext());
    return context;
  }
  
  
  Handle<Context> Factory::NewModuleContext(Handle<ScopeInfo> scope_info) {
    Handle<FixedArray> array =
        NewFixedArray(scope_info->ContextLength(), TENURED);
    array->set_map_no_write_barrier(*module_context_map());
    // Instance link will be set later.
    Handle<Context> context = Handle<Context>::cast(array);
    context->set_extension(Smi::FromInt(0));
    return context;
  }
  
  
  Handle<Context> Factory::NewFunctionContext(int length,
                                              Handle<JSFunction> function) {
    DCHECK(length >= Context::MIN_CONTEXT_SLOTS);
    Handle<FixedArray> array = NewFixedArray(length);
    array->set_map_no_write_barrier(*function_context_map());
    Handle<Context> context = Handle<Context>::cast(array);
    context->set_closure(*function);
    context->set_previous(function->context());
    context->set_extension(Smi::FromInt(0));
    context->set_global_object(function->context()->global_object());
    return context;
  }
  
  
  Handle<Context> Factory::NewCatchContext(Handle<JSFunction> function,
                                           Handle<Context> previous,
                                           Handle<String> name,
                                           Handle<Object> thrown_object) {
    STATIC_ASSERT(Context::MIN_CONTEXT_SLOTS == Context::THROWN_OBJECT_INDEX);
    Handle<FixedArray> array = NewFixedArray(Context::MIN_CONTEXT_SLOTS + 1);
    array->set_map_no_write_barrier(*catch_context_map());
    Handle<Context> context = Handle<Context>::cast(array);
    context->set_closure(*function);
    context->set_previous(*previous);
    context->set_extension(*name);
    context->set_global_object(previous->global_object());
    context->set(Context::THROWN_OBJECT_INDEX, *thrown_object);
    return context;
  }
  
  
  Handle<Context> Factory::NewWithContext(Handle<JSFunction> function,
                                          Handle<Context> previous,
                                          Handle<JSReceiver> extension) {
    Handle<FixedArray> array = NewFixedArray(Context::MIN_CONTEXT_SLOTS);
    array->set_map_no_write_barrier(*with_context_map());
    Handle<Context> context = Handle<Context>::cast(array);
    context->set_closure(*function);
    context->set_previous(*previous);
    context->set_extension(*extension);
    context->set_global_object(previous->global_object());
    return context;
  }
  
  
  Handle<Context> Factory::NewBlockContext(Handle<JSFunction> function,
                                           Handle<Context> previous,
                                           Handle<ScopeInfo> scope_info) {
    Handle<FixedArray> array =
        NewFixedArrayWithHoles(scope_info->ContextLength());
    array->set_map_no_write_barrier(*block_context_map());
    Handle<Context> context = Handle<Context>::cast(array);
    context->set_closure(*function);
    context->set_previous(*previous);
    context->set_extension(*scope_info);
    context->set_global_object(previous->global_object());
    return context;
  }
  
  
  Handle<Struct> Factory::NewStruct(InstanceType type) {
    CALL_HEAP_FUNCTION(
        isolate(),
        isolate()->heap()->AllocateStruct(type),
        Struct);
  }
  
  
  Handle<CodeCache> Factory::NewCodeCache() {
    Handle<CodeCache> code_cache =
        Handle<CodeCache>::cast(NewStruct(CODE_CACHE_TYPE));
    code_cache->set_default_cache(*empty_fixed_array(), SKIP_WRITE_BARRIER);
    code_cache->set_normal_type_cache(*undefined_value(), SKIP_WRITE_BARRIER);
    return code_cache;
  }
  
  
  Handle<AliasedArgumentsEntry> Factory::NewAliasedArgumentsEntry(
      int aliased_context_slot) {
    Handle<AliasedArgumentsEntry> entry = Handle<AliasedArgumentsEntry>::cast(
        NewStruct(ALIASED_ARGUMENTS_ENTRY_TYPE));
    entry->set_aliased_context_slot(aliased_context_slot);
    return entry;
  }
  
  
  Handle<DeclaredAccessorDescriptor> Factory::NewDeclaredAccessorDescriptor() {
    return Handle<DeclaredAccessorDescriptor>::cast(
        NewStruct(DECLARED_ACCESSOR_DESCRIPTOR_TYPE));
  }
  
  
  Handle<DeclaredAccessorInfo> Factory::NewDeclaredAccessorInfo() {
    Handle<DeclaredAccessorInfo> info =
        Handle<DeclaredAccessorInfo>::cast(
            NewStruct(DECLARED_ACCESSOR_INFO_TYPE));
    info->set_flag(0);  // Must clear the flag, it was initialized as undefined.
    return info;
  }
  
  
  Handle<ExecutableAccessorInfo> Factory::NewExecutableAccessorInfo() {
    Handle<ExecutableAccessorInfo> info =
        Handle<ExecutableAccessorInfo>::cast(
            NewStruct(EXECUTABLE_ACCESSOR_INFO_TYPE));
    info->set_flag(0);  // Must clear the flag, it was initialized as undefined.
    return info;
  }
  
  
  Handle<Script> Factory::NewScript(Handle<String> source) {
    // Generate id for this script.
    Heap* heap = isolate()->heap();
    int id = heap->last_script_id()->value() + 1;
    if (!Smi::IsValid(id) || id < 0) id = 1;
    heap->set_last_script_id(Smi::FromInt(id));
  
    // Create and initialize script object.
    Handle<Foreign> wrapper = NewForeign(0, TENURED);
    Handle<Script> script = Handle<Script>::cast(NewStruct(SCRIPT_TYPE));
    script->set_source(*source);
    script->set_name(heap->undefined_value());
    script->set_id(Smi::FromInt(id));
    script->set_line_offset(Smi::FromInt(0));
    script->set_column_offset(Smi::FromInt(0));
    script->set_context_data(heap->undefined_value());
    script->set_type(Smi::FromInt(Script::TYPE_NORMAL));
    script->set_wrapper(*wrapper);
    script->set_line_ends(heap->undefined_value());
    script->set_eval_from_shared(heap->undefined_value());
    script->set_eval_from_instructions_offset(Smi::FromInt(0));
    script->set_flags(Smi::FromInt(0));
  
    return script;
  }
  
  
  Handle<Foreign> Factory::NewForeign(Address addr, PretenureFlag pretenure) {
    CALL_HEAP_FUNCTION(isolate(),
                       isolate()->heap()->AllocateForeign(addr, pretenure),
                       Foreign);
  }
  
  
  Handle<Foreign> Factory::NewForeign(const AccessorDescriptor* desc) {
    return NewForeign((Address) desc, TENURED);
  }
  
  
  Handle<ByteArray> Factory::NewByteArray(int length, PretenureFlag pretenure) {
    DCHECK(0 <= length);
    CALL_HEAP_FUNCTION(
        isolate(),
        isolate()->heap()->AllocateByteArray(length, pretenure),
        ByteArray);
  }
  
  
  Handle<ExternalArray> Factory::NewExternalArray(int length,
                                                  ExternalArrayType array_type,
                                                  void* external_pointer,
                                                  PretenureFlag pretenure) {
    DCHECK(0 <= length && length <= Smi::kMaxValue);
    CALL_HEAP_FUNCTION(
        isolate(),
        isolate()->heap()->AllocateExternalArray(length,
                                                 array_type,
                                                 external_pointer,
                                                 pretenure),
        ExternalArray);
  }
  
  
  Handle<FixedTypedArrayBase> Factory::NewFixedTypedArray(
      int length,
      ExternalArrayType array_type,
      PretenureFlag pretenure) {
    DCHECK(0 <= length && length <= Smi::kMaxValue);
    CALL_HEAP_FUNCTION(
        isolate(),
        isolate()->heap()->AllocateFixedTypedArray(length,
                                                   array_type,
                                                   pretenure),
        FixedTypedArrayBase);
  }
  
  
  Handle<Cell> Factory::NewCell(Handle<Object> value) {
    AllowDeferredHandleDereference convert_to_cell;
    CALL_HEAP_FUNCTION(
        isolate(),
        isolate()->heap()->AllocateCell(*value),
        Cell);
  }
  
  
  Handle<PropertyCell> Factory::NewPropertyCellWithHole() {
    CALL_HEAP_FUNCTION(
        isolate(),
        isolate()->heap()->AllocatePropertyCell(),
        PropertyCell);
  }
  
  
  Handle<PropertyCell> Factory::NewPropertyCell(Handle<Object> value) {
    AllowDeferredHandleDereference convert_to_cell;
    Handle<PropertyCell> cell = NewPropertyCellWithHole();
    PropertyCell::SetValueInferType(cell, value);
    return cell;
  }
  
  
  Handle<AllocationSite> Factory::NewAllocationSite() {
    Handle<Map> map = allocation_site_map();
    Handle<AllocationSite> site = New<AllocationSite>(map, OLD_POINTER_SPACE);
    site->Initialize();
  
    // Link the site
    site->set_weak_next(isolate()->heap()->allocation_sites_list());
    isolate()->heap()->set_allocation_sites_list(*site);
    return site;
  }
  
  
  Handle<Map> Factory::NewMap(InstanceType type,
                              int instance_size,
                              ElementsKind elements_kind) {
    CALL_HEAP_FUNCTION(
        isolate(),
        isolate()->heap()->AllocateMap(type, instance_size, elements_kind),
        Map);
  }
  
  
  Handle<JSObject> Factory::CopyJSObject(Handle<JSObject> object) {
    CALL_HEAP_FUNCTION(isolate(),
                       isolate()->heap()->CopyJSObject(*object, NULL),
                       JSObject);
  }
  
  
  Handle<JSObject> Factory::CopyJSObjectWithAllocationSite(
      Handle<JSObject> object,
      Handle<AllocationSite> site) {
    CALL_HEAP_FUNCTION(isolate(),
                       isolate()->heap()->CopyJSObject(
                           *object,
                           site.is_null() ? NULL : *site),
                       JSObject);
  }
  
  
  Handle<FixedArray> Factory::CopyFixedArrayWithMap(Handle<FixedArray> array,
                                                    Handle<Map> map) {
    CALL_HEAP_FUNCTION(isolate(),
                       isolate()->heap()->CopyFixedArrayWithMap(*array, *map),
                       FixedArray);
  }
  
  
  Handle<FixedArray> Factory::CopyFixedArray(Handle<FixedArray> array) {
    CALL_HEAP_FUNCTION(isolate(),
                       isolate()->heap()->CopyFixedArray(*array),
                       FixedArray);
  }
  
  
  Handle<FixedArray> Factory::CopyAndTenureFixedCOWArray(
      Handle<FixedArray> array) {
    DCHECK(isolate()->heap()->InNewSpace(*array));
    CALL_HEAP_FUNCTION(isolate(),
                       isolate()->heap()->CopyAndTenureFixedCOWArray(*array),
                       FixedArray);
  }
  
  
  Handle<FixedDoubleArray> Factory::CopyFixedDoubleArray(
      Handle<FixedDoubleArray> array) {
    CALL_HEAP_FUNCTION(isolate(),
                       isolate()->heap()->CopyFixedDoubleArray(*array),
                       FixedDoubleArray);
  }
  
  
  Handle<ConstantPoolArray> Factory::CopyConstantPoolArray(
      Handle<ConstantPoolArray> array) {
    CALL_HEAP_FUNCTION(isolate(),
                       isolate()->heap()->CopyConstantPoolArray(*array),
                       ConstantPoolArray);
  }
  
  
  Handle<Object> Factory::NewNumber(double value,
                                    PretenureFlag pretenure) {
    // We need to distinguish the minus zero value and this cannot be
    // done after conversion to int. Doing this by comparing bit
    // patterns is faster than using fpclassify() et al.
    if (IsMinusZero(value)) return NewHeapNumber(-0.0, IMMUTABLE, pretenure);
  
    int int_value = FastD2I(value);
    if (value == int_value && Smi::IsValid(int_value)) {
      return handle(Smi::FromInt(int_value), isolate());
    }
  
    // Materialize the value in the heap.
    return NewHeapNumber(value, IMMUTABLE, pretenure);
  }
  
  
  Handle<Object> Factory::NewNumberFromInt(int32_t value,
                                           PretenureFlag pretenure) {
    if (Smi::IsValid(value)) return handle(Smi::FromInt(value), isolate());
    // Bypass NewNumber to avoid various redundant checks.
    return NewHeapNumber(FastI2D(value), IMMUTABLE, pretenure);
  }
  
  
  Handle<Object> Factory::NewNumberFromUint(uint32_t value,
                                            PretenureFlag pretenure) {
    int32_t int32v = static_cast<int32_t>(value);
    if (int32v >= 0 && Smi::IsValid(int32v)) {
      return handle(Smi::FromInt(int32v), isolate());
    }
    return NewHeapNumber(FastUI2D(value), IMMUTABLE, pretenure);
  }
  
  
  Handle<HeapNumber> Factory::NewHeapNumber(double value,
                                            MutableMode mode,
                                            PretenureFlag pretenure) {
    CALL_HEAP_FUNCTION(
        isolate(),
        isolate()->heap()->AllocateHeapNumber(value, mode, pretenure),
        HeapNumber);
  }
  
  
  Handle<Object> Factory::NewTypeError(const char* message,
                                       Vector< Handle<Object> > args) {
    return NewError("MakeTypeError", message, args);
  }
  
  
  Handle<Object> Factory::NewTypeError(Handle<String> message) {
    return NewError("$TypeError", message);
  }
  
  
  Handle<Object> Factory::NewRangeError(const char* message,
                                        Vector< Handle<Object> > args) {
    return NewError("MakeRangeError", message, args);
  }
  
  
  Handle<Object> Factory::NewRangeError(Handle<String> message) {
    return NewError("$RangeError", message);
  }
  
  
  Handle<Object> Factory::NewSyntaxError(const char* message,
                                         Handle<JSArray> args) {
    return NewError("MakeSyntaxError", message, args);
  }
  
  
  Handle<Object> Factory::NewSyntaxError(Handle<String> message) {
    return NewError("$SyntaxError", message);
  }
  
  
  Handle<Object> Factory::NewReferenceError(const char* message,
                                            Vector< Handle<Object> > args) {
    return NewError("MakeReferenceError", message, args);
  }
  
  
  Handle<Object> Factory::NewReferenceError(const char* message,
                                            Handle<JSArray> args) {
    return NewError("MakeReferenceError", message, args);
  }
  
  
  Handle<Object> Factory::NewReferenceError(Handle<String> message) {
    return NewError("$ReferenceError", message);
  }
  
  
  Handle<Object> Factory::NewError(const char* maker,
                                   const char* message,
                                   Vector< Handle<Object> > args) {
    // Instantiate a closeable HandleScope for EscapeFrom.
    v8::EscapableHandleScope scope(reinterpret_cast<v8::Isolate*>(isolate()));
    Handle<FixedArray> array = NewFixedArray(args.length());
    for (int i = 0; i < args.length(); i++) {
      array->set(i, *args[i]);
    }
    Handle<JSArray> object = NewJSArrayWithElements(array);
    Handle<Object> result = NewError(maker, message, object);
    return result.EscapeFrom(&scope);
  }
  
  
  Handle<Object> Factory::NewEvalError(const char* message,
                                       Vector< Handle<Object> > args) {
    return NewError("MakeEvalError", message, args);
  }
  
  
  Handle<Object> Factory::NewError(const char* message,
                                   Vector< Handle<Object> > args) {
    return NewError("MakeError", message, args);
  }
  
  
  Handle<String> Factory::EmergencyNewError(const char* message,
                                            Handle<JSArray> args) {
    const int kBufferSize = 1000;
    char buffer[kBufferSize];
    size_t space = kBufferSize;
    char* p = &buffer[0];
  
    Vector<char> v(buffer, kBufferSize);
    StrNCpy(v, message, space);
    space -= Min(space, strlen(message));
    p = &buffer[kBufferSize] - space;
  
    for (unsigned i = 0; i < ARRAY_SIZE(args); i++) {
      if (space > 0) {
        *p++ = ' ';
        space--;
        if (space > 0) {
          Handle<String> arg_str = Handle<String>::cast(
              Object::GetElement(isolate(), args, i).ToHandleChecked());
          SmartArrayPointer<char> arg = arg_str->ToCString();
          Vector<char> v2(p, static_cast<int>(space));
          StrNCpy(v2, arg.get(), space);
          space -= Min(space, strlen(arg.get()));
          p = &buffer[kBufferSize] - space;
        }
      }
    }
    if (space > 0) {
      *p = '\0';
    } else {
      buffer[kBufferSize - 1] = '\0';
    }
    return NewStringFromUtf8(CStrVector(buffer), TENURED).ToHandleChecked();
  }
  
  
  Handle<Object> Factory::NewError(const char* maker,
                                   const char* message,
                                   Handle<JSArray> args) {
    Handle<String> make_str = InternalizeUtf8String(maker);
    Handle<Object> fun_obj = Object::GetProperty(
        isolate()->js_builtins_object(), make_str).ToHandleChecked();
    // If the builtins haven't been properly configured yet this error
    // constructor may not have been defined.  Bail out.
    if (!fun_obj->IsJSFunction()) {
      return EmergencyNewError(message, args);
    }
    Handle<JSFunction> fun = Handle<JSFunction>::cast(fun_obj);
    Handle<Object> message_obj = InternalizeUtf8String(message);
    Handle<Object> argv[] = { message_obj, args };
  
    // Invoke the JavaScript factory method. If an exception is thrown while
    // running the factory method, use the exception as the result.
    Handle<Object> result;
    Handle<Object> exception;
    if (!Execution::TryCall(fun,
                            isolate()->js_builtins_object(),
                            ARRAY_SIZE(argv),
                            argv,
                            &exception).ToHandle(&result)) {
      return exception;
    }
    return result;
  }
  
  
  Handle<Object> Factory::NewError(Handle<String> message) {
    return NewError("$Error", message);
  }
  
  
  Handle<Object> Factory::NewError(const char* constructor,
                                   Handle<String> message) {
    Handle<String> constr = InternalizeUtf8String(constructor);
    Handle<JSFunction> fun = Handle<JSFunction>::cast(Object::GetProperty(
        isolate()->js_builtins_object(), constr).ToHandleChecked());
    Handle<Object> argv[] = { message };
  
    // Invoke the JavaScript factory method. If an exception is thrown while
    // running the factory method, use the exception as the result.
    Handle<Object> result;
    Handle<Object> exception;
    if (!Execution::TryCall(fun,
                            isolate()->js_builtins_object(),
                            ARRAY_SIZE(argv),
                            argv,
                            &exception).ToHandle(&result)) {
      return exception;
    }
    return result;
  }
  
  
  void Factory::InitializeFunction(Handle<JSFunction> function,
                                   Handle<SharedFunctionInfo> info,
                                   Handle<Context> context) {
    function->initialize_properties();
    function->initialize_elements();
    function->set_shared(*info);
    function->set_code(info->code());
    function->set_context(*context);
    function->set_prototype_or_initial_map(*the_hole_value());
    function->set_literals_or_bindings(*empty_fixed_array());
    function->set_next_function_link(*undefined_value());
    if (info->is_arrow()) function->RemovePrototype();
  }
  
  
  Handle<JSFunction> Factory::NewFunction(Handle<Map> map,
                                          Handle<SharedFunctionInfo> info,
                                          Handle<Context> context,
                                          PretenureFlag pretenure) {
    AllocationSpace space = pretenure == TENURED ? OLD_POINTER_SPACE : NEW_SPACE;
    Handle<JSFunction> result = New<JSFunction>(map, space);
    InitializeFunction(result, info, context);
    return result;
  }
  
  
  Handle<JSFunction> Factory::NewFunction(Handle<Map> map,
                                          Handle<String> name,
                                          MaybeHandle<Code> code) {
    Handle<Context> context(isolate()->native_context());
    Handle<SharedFunctionInfo> info = NewSharedFunctionInfo(name, code);
    DCHECK((info->strict_mode() == SLOPPY) &&
           (map.is_identical_to(isolate()->sloppy_function_map()) ||
            map.is_identical_to(
                isolate()->sloppy_function_without_prototype_map()) ||
            map.is_identical_to(
                isolate()->sloppy_function_with_readonly_prototype_map())));
    return NewFunction(map, info, context);
  }
  
  
  Handle<JSFunction> Factory::NewFunction(Handle<String> name) {
    return NewFunction(
        isolate()->sloppy_function_map(), name, MaybeHandle<Code>());
  }
  
  
  Handle<JSFunction> Factory::NewFunctionWithoutPrototype(Handle<String> name,
                                                          Handle<Code> code) {
    return NewFunction(
        isolate()->sloppy_function_without_prototype_map(), name, code);
  }
  
  
  Handle<JSFunction> Factory::NewFunction(Handle<String> name,
                                          Handle<Code> code,
                                          Handle<Object> prototype,
                                          bool read_only_prototype) {
    Handle<Map> map = read_only_prototype
        ? isolate()->sloppy_function_with_readonly_prototype_map()
        : isolate()->sloppy_function_map();
    Handle<JSFunction> result = NewFunction(map, name, code);
    result->set_prototype_or_initial_map(*prototype);
    return result;
  }
  
  
  Handle<JSFunction> Factory::NewFunction(Handle<String> name,
                                          Handle<Code> code,
                                          Handle<Object> prototype,
                                          InstanceType type,
                                          int instance_size,
                                          bool read_only_prototype) {
    // Allocate the function
    Handle<JSFunction> function = NewFunction(
        name, code, prototype, read_only_prototype);
  
    Handle<Map> initial_map = NewMap(
        type, instance_size, GetInitialFastElementsKind());
    if (prototype->IsTheHole() && !function->shared()->is_generator()) {
      prototype = NewFunctionPrototype(function);
    }
  
    JSFunction::SetInitialMap(function, initial_map,
                              Handle<JSReceiver>::cast(prototype));
  
    return function;
  }
  
  
  Handle<JSFunction> Factory::NewFunction(Handle<String> name,
                                          Handle<Code> code,
                                          InstanceType type,
                                          int instance_size) {
    return NewFunction(name, code, the_hole_value(), type, instance_size);
  }
  
  
  Handle<JSObject> Factory::NewFunctionPrototype(Handle<JSFunction> function) {
    // Make sure to use globals from the function's context, since the function
    // can be from a different context.
    Handle<Context> native_context(function->context()->native_context());
    Handle<Map> new_map;
    if (function->shared()->is_generator()) {
      // Generator prototypes can share maps since they don't have "constructor"
      // properties.
      new_map = handle(native_context->generator_object_prototype_map());
    } else {
      // Each function prototype gets a fresh map to avoid unwanted sharing of
      // maps between prototypes of different constructors.
      Handle<JSFunction> object_function(native_context->object_function());
      DCHECK(object_function->has_initial_map());
      new_map = handle(object_function->initial_map());
    }
  
    DCHECK(!new_map->is_prototype_map());
    Handle<JSObject> prototype = NewJSObjectFromMap(new_map);
  
    if (!function->shared()->is_generator()) {
      JSObject::AddProperty(prototype, constructor_string(), function, DONT_ENUM);
    }
  
    return prototype;
  }
  
  
  Handle<JSFunction> Factory::NewFunctionFromSharedFunctionInfo(
      Handle<SharedFunctionInfo> info,
      Handle<Context> context,
      PretenureFlag pretenure) {
    int map_index = Context::FunctionMapIndex(info->strict_mode(),
                                              info->is_generator());
    Handle<Map> map(Map::cast(context->native_context()->get(map_index)));
    Handle<JSFunction> result = NewFunction(map, info, context, pretenure);
  
    if (info->ic_age() != isolate()->heap()->global_ic_age()) {
      info->ResetForNewContext(isolate()->heap()->global_ic_age());
    }
  
    int index = info->SearchOptimizedCodeMap(context->native_context(),
                                             BailoutId::None());
    if (!info->bound() && index < 0) {
      int number_of_literals = info->num_literals();
      Handle<FixedArray> literals = NewFixedArray(number_of_literals, pretenure);
      if (number_of_literals > 0) {
        // Store the native context in the literals array prefix. This
        // context will be used when creating object, regexp and array
        // literals in this function.
        literals->set(JSFunction::kLiteralNativeContextIndex,
                      context->native_context());
      }
      result->set_literals(*literals);
    }
  
    if (index > 0) {
      // Caching of optimized code enabled and optimized code found.
      FixedArray* literals = info->GetLiteralsFromOptimizedCodeMap(index);
      if (literals != NULL) result->set_literals(literals);
      Code* code = info->GetCodeFromOptimizedCodeMap(index);
      DCHECK(!code->marked_for_deoptimization());
      result->ReplaceCode(code);
      return result;
    }
  
    if (isolate()->use_crankshaft() &&
        FLAG_always_opt &&
        result->is_compiled() &&
        !info->is_toplevel() &&
        info->allows_lazy_compilation() &&
        !info->optimization_disabled() &&
        !isolate()->DebuggerHasBreakPoints()) {
      result->MarkForOptimization();
    }
    return result;
  }
  
  
  Handle<ScopeInfo> Factory::NewScopeInfo(int length) {
    Handle<FixedArray> array = NewFixedArray(length, TENURED);
    array->set_map_no_write_barrier(*scope_info_map());
    Handle<ScopeInfo> scope_info = Handle<ScopeInfo>::cast(array);
    return scope_info;
  }
  
  
  Handle<JSObject> Factory::NewExternal(void* value) {
    Handle<Foreign> foreign = NewForeign(static_cast<Address>(value));
    Handle<JSObject> external = NewJSObjectFromMap(external_map());
    external->SetInternalField(0, *foreign);
    return external;
  }
  
  
  Handle<Code> Factory::NewCodeRaw(int object_size, bool immovable) {
    CALL_HEAP_FUNCTION(isolate(),
                       isolate()->heap()->AllocateCode(object_size, immovable),
                       Code);
  }
  
  
  Handle<Code> Factory::NewCode(const CodeDesc& desc,
                                Code::Flags flags,
                                Handle<Object> self_ref,
                                bool immovable,
                                bool crankshafted,
                                int prologue_offset,
                                bool is_debug) {
    Handle<ByteArray> reloc_info = NewByteArray(desc.reloc_size, TENURED);
    Handle<ConstantPoolArray> constant_pool =
        desc.origin->NewConstantPool(isolate());
  
    // Compute size.
    int body_size = RoundUp(desc.instr_size, kObjectAlignment);
    int obj_size = Code::SizeFor(body_size);
  
    Handle<Code> code = NewCodeRaw(obj_size, immovable);
    DCHECK(isolate()->code_range() == NULL ||
           !isolate()->code_range()->valid() ||
           isolate()->code_range()->contains(code->address()));
  
    // The code object has not been fully initialized yet.  We rely on the
    // fact that no allocation will happen from this point on.
    DisallowHeapAllocation no_gc;
    code->set_gc_metadata(Smi::FromInt(0));
    code->set_ic_age(isolate()->heap()->global_ic_age());
    code->set_instruction_size(desc.instr_size);
    code->set_relocation_info(*reloc_info);
    code->set_flags(flags);
    code->set_raw_kind_specific_flags1(0);
    code->set_raw_kind_specific_flags2(0);
    code->set_is_crankshafted(crankshafted);
    code->set_deoptimization_data(*empty_fixed_array(), SKIP_WRITE_BARRIER);
    code->set_raw_type_feedback_info(Smi::FromInt(0));
    code->set_next_code_link(*undefined_value());
    code->set_handler_table(*empty_fixed_array(), SKIP_WRITE_BARRIER);
    code->set_prologue_offset(prologue_offset);
    if (code->kind() == Code::OPTIMIZED_FUNCTION) {
      code->set_marked_for_deoptimization(false);
    }
  
    if (is_debug) {
      DCHECK(code->kind() == Code::FUNCTION);
      code->set_has_debug_break_slots(true);
    }
  
    desc.origin->PopulateConstantPool(*constant_pool);
    code->set_constant_pool(*constant_pool);
  
    // Allow self references to created code object by patching the handle to
    // point to the newly allocated Code object.
    if (!self_ref.is_null()) *(self_ref.location()) = *code;
  
    // Migrate generated code.
    // The generated code can contain Object** values (typically from handles)
    // that are dereferenced during the copy to point directly to the actual heap
    // objects. These pointers can include references to the code object itself,
    // through the self_reference parameter.
    code->CopyFrom(desc);
  
  #ifdef VERIFY_HEAP
    if (FLAG_verify_heap) code->ObjectVerify();
  #endif
    return code;
  }
  
  
  Handle<Code> Factory::CopyCode(Handle<Code> code) {
    CALL_HEAP_FUNCTION(isolate(),
                       isolate()->heap()->CopyCode(*code),
                       Code);
  }
  
  
  Handle<Code> Factory::CopyCode(Handle<Code> code, Vector<byte> reloc_info) {
    CALL_HEAP_FUNCTION(isolate(),
                       isolate()->heap()->CopyCode(*code, reloc_info),
                       Code);
  }
  
  
  Handle<JSObject> Factory::NewJSObject(Handle<JSFunction> constructor,
                                        PretenureFlag pretenure) {
    JSFunction::EnsureHasInitialMap(constructor);
    CALL_HEAP_FUNCTION(
        isolate(),
        isolate()->heap()->AllocateJSObject(*constructor, pretenure), JSObject);
  }
  
  
  Handle<JSObject> Factory::NewJSObjectWithMemento(
      Handle<JSFunction> constructor,
      Handle<AllocationSite> site) {
    JSFunction::EnsureHasInitialMap(constructor);
    CALL_HEAP_FUNCTION(
        isolate(),
        isolate()->heap()->AllocateJSObject(*constructor, NOT_TENURED, *site),
        JSObject);
  }
  
  
  Handle<JSModule> Factory::NewJSModule(Handle<Context> context,
                                        Handle<ScopeInfo> scope_info) {
    // Allocate a fresh map. Modules do not have a prototype.
    Handle<Map> map = NewMap(JS_MODULE_TYPE, JSModule::kSize);
    // Allocate the object based on the map.
    Handle<JSModule> module =
        Handle<JSModule>::cast(NewJSObjectFromMap(map, TENURED));
    module->set_context(*context);
    module->set_scope_info(*scope_info);
    return module;
  }
  
  
  Handle<GlobalObject> Factory::NewGlobalObject(Handle<JSFunction> constructor) {
    DCHECK(constructor->has_initial_map());
    Handle<Map> map(constructor->initial_map());
    DCHECK(map->is_dictionary_map());
  
    // Make sure no field properties are described in the initial map.
    // This guarantees us that normalizing the properties does not
    // require us to change property values to PropertyCells.
    DCHECK(map->NextFreePropertyIndex() == 0);
  
    // Make sure we don't have a ton of pre-allocated slots in the
    // global objects. They will be unused once we normalize the object.
    DCHECK(map->unused_property_fields() == 0);
    DCHECK(map->inobject_properties() == 0);
  
    // Initial size of the backing store to avoid resize of the storage during
    // bootstrapping. The size differs between the JS global object ad the
    // builtins object.
    int initial_size = map->instance_type() == JS_GLOBAL_OBJECT_TYPE ? 64 : 512;
  
    // Allocate a dictionary object for backing storage.
    int at_least_space_for = map->NumberOfOwnDescriptors() * 2 + initial_size;
    Handle<NameDictionary> dictionary =
        NameDictionary::New(isolate(), at_least_space_for);
  
    // The global object might be created from an object template with accessors.
    // Fill these accessors into the dictionary.
    Handle<DescriptorArray> descs(map->instance_descriptors());
    for (int i = 0; i < map->NumberOfOwnDescriptors(); i++) {
      PropertyDetails details = descs->GetDetails(i);
      DCHECK(details.type() == CALLBACKS);  // Only accessors are expected.
      PropertyDetails d = PropertyDetails(details.attributes(), CALLBACKS, i + 1);
      Handle<Name> name(descs->GetKey(i));
      Handle<Object> value(descs->GetCallbacksObject(i), isolate());
      Handle<PropertyCell> cell = NewPropertyCell(value);
      // |dictionary| already contains enough space for all properties.
      USE(NameDictionary::Add(dictionary, name, cell, d));
    }
  
    // Allocate the global object and initialize it with the backing store.
    Handle<GlobalObject> global = New<GlobalObject>(map, OLD_POINTER_SPACE);
    isolate()->heap()->InitializeJSObjectFromMap(*global, *dictionary, *map);
  
    // Create a new map for the global object.
    Handle<Map> new_map = Map::CopyDropDescriptors(map);
    new_map->set_dictionary_map(true);
  
    // Set up the global object as a normalized object.
    global->set_map(*new_map);
    global->set_properties(*dictionary);
  
    // Make sure result is a global object with properties in dictionary.
    DCHECK(global->IsGlobalObject() && !global->HasFastProperties());
    return global;
  }
  
  
  Handle<JSObject> Factory::NewJSObjectFromMap(
      Handle<Map> map,
      PretenureFlag pretenure,
      bool alloc_props,
      Handle<AllocationSite> allocation_site) {
    CALL_HEAP_FUNCTION(
        isolate(),
        isolate()->heap()->AllocateJSObjectFromMap(
            *map,
            pretenure,
            alloc_props,
            allocation_site.is_null() ? NULL : *allocation_site),
        JSObject);
  }
  
  
  Handle<JSArray> Factory::NewJSArray(ElementsKind elements_kind,
                                      PretenureFlag pretenure) {
    Context* native_context = isolate()->context()->native_context();
    JSFunction* array_function = native_context->array_function();
    Map* map = array_function->initial_map();
    Map* transition_map = isolate()->get_initial_js_array_map(elements_kind);
    if (transition_map != NULL) map = transition_map;
    return Handle<JSArray>::cast(NewJSObjectFromMap(handle(map), pretenure));
  }
  
  
  Handle<JSArray> Factory::NewJSArray(ElementsKind elements_kind,
                                      int length,
                                      int capacity,
                                      ArrayStorageAllocationMode mode,
                                      PretenureFlag pretenure) {
    Handle<JSArray> array = NewJSArray(elements_kind, pretenure);
    NewJSArrayStorage(array, length, capacity, mode);
    return array;
  }
  
  
  Handle<JSArray> Factory::NewJSArrayWithElements(Handle<FixedArrayBase> elements,
                                                  ElementsKind elements_kind,
                                                  int length,
                                                  PretenureFlag pretenure) {
    DCHECK(length <= elements->length());
    Handle<JSArray> array = NewJSArray(elements_kind, pretenure);
  
    array->set_elements(*elements);
    array->set_length(Smi::FromInt(length));
    JSObject::ValidateElements(array);
    return array;
  }
  
  
  void Factory::NewJSArrayStorage(Handle<JSArray> array,
                                  int length,
                                  int capacity,
                                  ArrayStorageAllocationMode mode) {
    DCHECK(capacity >= length);
  
    if (capacity == 0) {
      array->set_length(Smi::FromInt(0));
      array->set_elements(*empty_fixed_array());
      return;
    }
  
    Handle<FixedArrayBase> elms;
    ElementsKind elements_kind = array->GetElementsKind();
    if (IsFastDoubleElementsKind(elements_kind)) {
      if (mode == DONT_INITIALIZE_ARRAY_ELEMENTS) {
        elms = NewFixedDoubleArray(capacity);
      } else {
        DCHECK(mode == INITIALIZE_ARRAY_ELEMENTS_WITH_HOLE);
        elms = NewFixedDoubleArrayWithHoles(capacity);
      }
    } else {
      DCHECK(IsFastSmiOrObjectElementsKind(elements_kind));
      if (mode == DONT_INITIALIZE_ARRAY_ELEMENTS) {
        elms = NewUninitializedFixedArray(capacity);
      } else {
        DCHECK(mode == INITIALIZE_ARRAY_ELEMENTS_WITH_HOLE);
        elms = NewFixedArrayWithHoles(capacity);
      }
    }
  
    array->set_elements(*elms);
    array->set_length(Smi::FromInt(length));
  }
  
  
  Handle<JSGeneratorObject> Factory::NewJSGeneratorObject(
      Handle<JSFunction> function) {
    DCHECK(function->shared()->is_generator());
    JSFunction::EnsureHasInitialMap(function);
    Handle<Map> map(function->initial_map());
    DCHECK(map->instance_type() == JS_GENERATOR_OBJECT_TYPE);
    CALL_HEAP_FUNCTION(
        isolate(),
        isolate()->heap()->AllocateJSObjectFromMap(*map),
        JSGeneratorObject);
  }
  
  
  Handle<JSArrayBuffer> Factory::NewJSArrayBuffer() {
    Handle<JSFunction> array_buffer_fun(
        isolate()->native_context()->array_buffer_fun());
    CALL_HEAP_FUNCTION(
        isolate(),
        isolate()->heap()->AllocateJSObject(*array_buffer_fun),
        JSArrayBuffer);
  }
  
  
  Handle<JSDataView> Factory::NewJSDataView() {
    Handle<JSFunction> data_view_fun(
        isolate()->native_context()->data_view_fun());
    CALL_HEAP_FUNCTION(
        isolate(),
        isolate()->heap()->AllocateJSObject(*data_view_fun),
        JSDataView);
  }
  
  
  static JSFunction* GetTypedArrayFun(ExternalArrayType type,
                                      Isolate* isolate) {
    Context* native_context = isolate->context()->native_context();
    switch (type) {
  #define TYPED_ARRAY_FUN(Type, type, TYPE, ctype, size)                        \
      case kExternal##Type##Array:                                              \
        return native_context->type##_array_fun();
  
      TYPED_ARRAYS(TYPED_ARRAY_FUN)
  #undef TYPED_ARRAY_FUN
  
      default:
        UNREACHABLE();
        return NULL;
    }
  }
  
  
  Handle<JSTypedArray> Factory::NewJSTypedArray(ExternalArrayType type) {
    Handle<JSFunction> typed_array_fun_handle(GetTypedArrayFun(type, isolate()));
  
    CALL_HEAP_FUNCTION(
        isolate(),
        isolate()->heap()->AllocateJSObject(*typed_array_fun_handle),
        JSTypedArray);
  }
  
  
  Handle<JSProxy> Factory::NewJSProxy(Handle<Object> handler,
                                      Handle<Object> prototype) {
    // Allocate map.
    // TODO(rossberg): Once we optimize proxies, think about a scheme to share
    // maps. Will probably depend on the identity of the handler object, too.
    Handle<Map> map = NewMap(JS_PROXY_TYPE, JSProxy::kSize);
    map->set_prototype(*prototype);
  
    // Allocate the proxy object.
    Handle<JSProxy> result = New<JSProxy>(map, NEW_SPACE);
    result->InitializeBody(map->instance_size(), Smi::FromInt(0));
    result->set_handler(*handler);
    result->set_hash(*undefined_value(), SKIP_WRITE_BARRIER);
    return result;
  }
  
  
  Handle<JSProxy> Factory::NewJSFunctionProxy(Handle<Object> handler,
                                              Handle<Object> call_trap,
                                              Handle<Object> construct_trap,
                                              Handle<Object> prototype) {
    // Allocate map.
    // TODO(rossberg): Once we optimize proxies, think about a scheme to share
    // maps. Will probably depend on the identity of the handler object, too.
    Handle<Map> map = NewMap(JS_FUNCTION_PROXY_TYPE, JSFunctionProxy::kSize);
    map->set_prototype(*prototype);
  
    // Allocate the proxy object.
    Handle<JSFunctionProxy> result = New<JSFunctionProxy>(map, NEW_SPACE);
    result->InitializeBody(map->instance_size(), Smi::FromInt(0));
    result->set_handler(*handler);
    result->set_hash(*undefined_value(), SKIP_WRITE_BARRIER);
    result->set_call_trap(*call_trap);
    result->set_construct_trap(*construct_trap);
    return result;
  }
  
  
  void Factory::ReinitializeJSReceiver(Handle<JSReceiver> object,
                                       InstanceType type,
                                       int size) {
    DCHECK(type >= FIRST_JS_OBJECT_TYPE);
  
    // Allocate fresh map.
    // TODO(rossberg): Once we optimize proxies, cache these maps.
    Handle<Map> map = NewMap(type, size);
  
    // Check that the receiver has at least the size of the fresh object.
    int size_difference = object->map()->instance_size() - map->instance_size();
    DCHECK(size_difference >= 0);
  
    map->set_prototype(object->map()->prototype());
  
    // Allocate the backing storage for the properties.
    int prop_size = map->InitialPropertiesLength();
    Handle<FixedArray> properties = NewFixedArray(prop_size, TENURED);
  
    Heap* heap = isolate()->heap();
    MaybeHandle<SharedFunctionInfo> shared;
    if (type == JS_FUNCTION_TYPE) {
      OneByteStringKey key(STATIC_ASCII_VECTOR("<freezing call trap>"),
                           heap->HashSeed());
      Handle<String> name = InternalizeStringWithKey(&key);
      shared = NewSharedFunctionInfo(name, MaybeHandle<Code>());
    }
  
    // In order to keep heap in consistent state there must be no allocations
    // before object re-initialization is finished and filler object is installed.
    DisallowHeapAllocation no_allocation;
  
    // Put in filler if the new object is smaller than the old.
    if (size_difference > 0) {
      Address address = object->address();
      heap->CreateFillerObjectAt(address + map->instance_size(), size_difference);
      heap->AdjustLiveBytes(address, -size_difference, Heap::FROM_MUTATOR);
    }
  
    // Reset the map for the object.
    object->synchronized_set_map(*map);
    Handle<JSObject> jsobj = Handle<JSObject>::cast(object);
  
    // Reinitialize the object from the constructor map.
    heap->InitializeJSObjectFromMap(*jsobj, *properties, *map);
  
    // Functions require some minimal initialization.
    if (type == JS_FUNCTION_TYPE) {
      map->set_function_with_prototype(true);
      Handle<JSFunction> js_function = Handle<JSFunction>::cast(object);
      Handle<Context> context(isolate()->native_context());
      InitializeFunction(js_function, shared.ToHandleChecked(), context);
    }
  }
  
  
  void Factory::ReinitializeJSGlobalProxy(Handle<JSGlobalProxy> object,
                                          Handle<JSFunction> constructor) {
    DCHECK(constructor->has_initial_map());
    Handle<Map> map(constructor->initial_map(), isolate());
  
    // The proxy's hash should be retained across reinitialization.
    Handle<Object> hash(object->hash(), isolate());
  
    // Check that the already allocated object has the same size and type as
    // objects allocated using the constructor.
    DCHECK(map->instance_size() == object->map()->instance_size());
    DCHECK(map->instance_type() == object->map()->instance_type());
  
    // Allocate the backing storage for the properties.
    int prop_size = map->InitialPropertiesLength();
    Handle<FixedArray> properties = NewFixedArray(prop_size, TENURED);
  
    // In order to keep heap in consistent state there must be no allocations
    // before object re-initialization is finished.
    DisallowHeapAllocation no_allocation;
  
    // Reset the map for the object.
    object->synchronized_set_map(*map);
  
    Heap* heap = isolate()->heap();
    // Reinitialize the object from the constructor map.
    heap->InitializeJSObjectFromMap(*object, *properties, *map);
  
    // Restore the saved hash.
    object->set_hash(*hash);
  }
  
  
  void Factory::BecomeJSObject(Handle<JSReceiver> object) {
    ReinitializeJSReceiver(object, JS_OBJECT_TYPE, JSObject::kHeaderSize);
  }
  
  
  void Factory::BecomeJSFunction(Handle<JSReceiver> object) {
    ReinitializeJSReceiver(object, JS_FUNCTION_TYPE, JSFunction::kSize);
  }
  
  
  Handle<FixedArray> Factory::NewTypeFeedbackVector(int slot_count) {
    // Ensure we can skip the write barrier
    DCHECK_EQ(isolate()->heap()->uninitialized_symbol(),
              *TypeFeedbackInfo::UninitializedSentinel(isolate()));
  
    CALL_HEAP_FUNCTION(
        isolate(),
        isolate()->heap()->AllocateFixedArrayWithFiller(
            slot_count,
            TENURED,
            *TypeFeedbackInfo::UninitializedSentinel(isolate())),
        FixedArray);
  }
  
  
  Handle<SharedFunctionInfo> Factory::NewSharedFunctionInfo(
      Handle<String> name, int number_of_literals, bool is_generator,
      bool is_arrow, Handle<Code> code, Handle<ScopeInfo> scope_info,
      Handle<FixedArray> feedback_vector) {
    Handle<SharedFunctionInfo> shared = NewSharedFunctionInfo(name, code);
    shared->set_scope_info(*scope_info);
    shared->set_feedback_vector(*feedback_vector);
    shared->set_is_arrow(is_arrow);
    int literals_array_size = number_of_literals;
    // If the function contains object, regexp or array literals,
    // allocate extra space for a literals array prefix containing the
    // context.
    if (number_of_literals > 0) {
      literals_array_size += JSFunction::kLiteralsPrefixSize;
    }
    shared->set_num_literals(literals_array_size);
    if (is_generator) {
      shared->set_instance_class_name(isolate()->heap()->Generator_string());
      shared->DisableOptimization(kGenerator);
    }
    return shared;
  }
  
  
  Handle<JSMessageObject> Factory::NewJSMessageObject(
      Handle<String> type,
      Handle<JSArray> arguments,
      int start_position,
      int end_position,
      Handle<Object> script,
      Handle<Object> stack_frames) {
    Handle<Map> map = message_object_map();
    Handle<JSMessageObject> message = New<JSMessageObject>(map, NEW_SPACE);
    message->set_properties(*empty_fixed_array(), SKIP_WRITE_BARRIER);
    message->initialize_elements();
    message->set_elements(*empty_fixed_array(), SKIP_WRITE_BARRIER);
    message->set_type(*type);
    message->set_arguments(*arguments);
    message->set_start_position(start_position);
    message->set_end_position(end_position);
    message->set_script(*script);
    message->set_stack_frames(*stack_frames);
    return message;
  }
  
  
  Handle<SharedFunctionInfo> Factory::NewSharedFunctionInfo(
      Handle<String> name,
      MaybeHandle<Code> maybe_code) {
    Handle<Map> map = shared_function_info_map();
    Handle<SharedFunctionInfo> share = New<SharedFunctionInfo>(map,
                                                               OLD_POINTER_SPACE);
  
    // Set pointer fields.
    share->set_name(*name);
    Handle<Code> code;
    if (!maybe_code.ToHandle(&code)) {
      code = handle(isolate()->builtins()->builtin(Builtins::kIllegal));
    }
    share->set_code(*code);
    share->set_optimized_code_map(Smi::FromInt(0));
    share->set_scope_info(ScopeInfo::Empty(isolate()));
    Code* construct_stub =
        isolate()->builtins()->builtin(Builtins::kJSConstructStubGeneric);
    share->set_construct_stub(construct_stub);
    share->set_instance_class_name(*Object_string());
    share->set_function_data(*undefined_value(), SKIP_WRITE_BARRIER);
    share->set_script(*undefined_value(), SKIP_WRITE_BARRIER);
    share->set_debug_info(*undefined_value(), SKIP_WRITE_BARRIER);
    share->set_inferred_name(*empty_string(), SKIP_WRITE_BARRIER);
    share->set_feedback_vector(*empty_fixed_array(), SKIP_WRITE_BARRIER);
    share->set_profiler_ticks(0);
    share->set_ast_node_count(0);
    share->set_counters(0);
  
    // Set integer fields (smi or int, depending on the architecture).
    share->set_length(0);
    share->set_formal_parameter_count(0);
    share->set_expected_nof_properties(0);
    share->set_num_literals(0);
    share->set_start_position_and_type(0);
    share->set_end_position(0);
    share->set_function_token_position(0);
    // All compiler hints default to false or 0.
    share->set_compiler_hints(0);
    share->set_opt_count_and_bailout_reason(0);
  
    return share;
  }
  
  
  static inline int NumberCacheHash(Handle<FixedArray> cache,
                                    Handle<Object> number) {
    int mask = (cache->length() >> 1) - 1;
    if (number->IsSmi()) {
      return Handle<Smi>::cast(number)->value() & mask;
    } else {
      DoubleRepresentation rep(number->Number());
      return
          (static_cast<int>(rep.bits) ^ static_cast<int>(rep.bits >> 32)) & mask;
    }
  }
  
  
  Handle<Object> Factory::GetNumberStringCache(Handle<Object> number) {
    DisallowHeapAllocation no_gc;
    int hash = NumberCacheHash(number_string_cache(), number);
    Object* key = number_string_cache()->get(hash * 2);
    if (key == *number || (key->IsHeapNumber() && number->IsHeapNumber() &&
                           key->Number() == number->Number())) {
      return Handle<String>(
          String::cast(number_string_cache()->get(hash * 2 + 1)), isolate());
    }
    return undefined_value();
  }
  
  
  void Factory::SetNumberStringCache(Handle<Object> number,
                                     Handle<String> string) {
    int hash = NumberCacheHash(number_string_cache(), number);
    if (number_string_cache()->get(hash * 2) != *undefined_value()) {
      int full_size = isolate()->heap()->FullSizeNumberStringCacheLength();
      if (number_string_cache()->length() != full_size) {
        // The first time we have a hash collision, we move to the full sized
        // number string cache.  The idea is to have a small number string
        // cache in the snapshot to keep  boot-time memory usage down.
        // If we expand the number string cache already while creating
        // the snapshot then that didn't work out.
        DCHECK(!isolate()->serializer_enabled() || FLAG_extra_code != NULL);
        Handle<FixedArray> new_cache = NewFixedArray(full_size, TENURED);
        isolate()->heap()->set_number_string_cache(*new_cache);
        return;
      }
    }
    number_string_cache()->set(hash * 2, *number);
    number_string_cache()->set(hash * 2 + 1, *string);
  }
  
  
  Handle<String> Factory::NumberToString(Handle<Object> number,
                                         bool check_number_string_cache) {
    isolate()->counters()->number_to_string_runtime()->Increment();
    if (check_number_string_cache) {
      Handle<Object> cached = GetNumberStringCache(number);
      if (!cached->IsUndefined()) return Handle<String>::cast(cached);
    }
  
    char arr[100];
    Vector<char> buffer(arr, ARRAY_SIZE(arr));
    const char* str;
    if (number->IsSmi()) {
      int num = Handle<Smi>::cast(number)->value();
      str = IntToCString(num, buffer);
    } else {
      double num = Handle<HeapNumber>::cast(number)->value();
      str = DoubleToCString(num, buffer);
    }
  
    // We tenure the allocated string since it is referenced from the
    // number-string cache which lives in the old space.
    Handle<String> js_string = NewStringFromAsciiChecked(str, TENURED);
    SetNumberStringCache(number, js_string);
    return js_string;
  }
  
  
  Handle<DebugInfo> Factory::NewDebugInfo(Handle<SharedFunctionInfo> shared) {
    // Get the original code of the function.
    Handle<Code> code(shared->code());
  
    // Create a copy of the code before allocating the debug info object to avoid
    // allocation while setting up the debug info object.
    Handle<Code> original_code(*Factory::CopyCode(code));
  
    // Allocate initial fixed array for active break points before allocating the
    // debug info object to avoid allocation while setting up the debug info
    // object.
    Handle<FixedArray> break_points(
        NewFixedArray(DebugInfo::kEstimatedNofBreakPointsInFunction));
  
    // Create and set up the debug info object. Debug info contains function, a
    // copy of the original code, the executing code and initial fixed array for
    // active break points.
    Handle<DebugInfo> debug_info =
        Handle<DebugInfo>::cast(NewStruct(DEBUG_INFO_TYPE));
    debug_info->set_shared(*shared);
    debug_info->set_original_code(*original_code);
    debug_info->set_code(*code);
    debug_info->set_break_points(*break_points);
  
    // Link debug info to function.
    shared->set_debug_info(*debug_info);
  
    return debug_info;
  }
  
  
  Handle<JSObject> Factory::NewArgumentsObject(Handle<JSFunction> callee,
                                               int length) {
    bool strict_mode_callee = callee->shared()->strict_mode() == STRICT;
    Handle<Map> map = strict_mode_callee ? isolate()->strict_arguments_map()
                                         : isolate()->sloppy_arguments_map();
  
    AllocationSiteUsageContext context(isolate(), Handle<AllocationSite>(),
                                       false);
    DCHECK(!isolate()->has_pending_exception());
    Handle<JSObject> result = NewJSObjectFromMap(map);
    Handle<Smi> value(Smi::FromInt(length), isolate());
    Object::SetProperty(result, length_string(), value, STRICT).Assert();
    if (!strict_mode_callee) {
      Object::SetProperty(result, callee_string(), callee, STRICT).Assert();
    }
    return result;
  }
  
  
  Handle<JSFunction> Factory::CreateApiFunction(
      Handle<FunctionTemplateInfo> obj,
      Handle<Object> prototype,
      ApiInstanceType instance_type) {
    Handle<Code> code = isolate()->builtins()->HandleApiCall();
    Handle<Code> construct_stub = isolate()->builtins()->JSConstructStubApi();
  
    Handle<JSFunction> result;
    if (obj->remove_prototype()) {
      result = NewFunctionWithoutPrototype(empty_string(), code);
    } else {
      int internal_field_count = 0;
      if (!obj->instance_template()->IsUndefined()) {
        Handle<ObjectTemplateInfo> instance_template =
            Handle<ObjectTemplateInfo>(
                ObjectTemplateInfo::cast(obj->instance_template()));
        internal_field_count =
            Smi::cast(instance_template->internal_field_count())->value();
      }
  
      // TODO(svenpanne) Kill ApiInstanceType and refactor things by generalizing
      // JSObject::GetHeaderSize.
      int instance_size = kPointerSize * internal_field_count;
      InstanceType type;
      switch (instance_type) {
        case JavaScriptObjectType:
          type = JS_OBJECT_TYPE;
          instance_size += JSObject::kHeaderSize;
          break;
        case GlobalObjectType:
          type = JS_GLOBAL_OBJECT_TYPE;
          instance_size += JSGlobalObject::kSize;
          break;
        case GlobalProxyType:
          type = JS_GLOBAL_PROXY_TYPE;
          instance_size += JSGlobalProxy::kSize;
          break;
        default:
          UNREACHABLE();
          type = JS_OBJECT_TYPE;  // Keep the compiler happy.
          break;
      }
  
      result = NewFunction(empty_string(), code, prototype, type,
                           instance_size, obj->read_only_prototype());
    }
  
    result->shared()->set_length(obj->length());
    Handle<Object> class_name(obj->class_name(), isolate());
    if (class_name->IsString()) {
      result->shared()->set_instance_class_name(*class_name);
      result->shared()->set_name(*class_name);
    }
    result->shared()->set_function_data(*obj);
    result->shared()->set_construct_stub(*construct_stub);
    result->shared()->DontAdaptArguments();
  
    if (obj->remove_prototype()) {
      DCHECK(result->shared()->IsApiFunction());
      DCHECK(!result->has_initial_map());
      DCHECK(!result->has_prototype());
      return result;
    }
  
    if (prototype->IsTheHole()) {
  #ifdef DEBUG
      LookupIterator it(handle(JSObject::cast(result->prototype())),
                        constructor_string(),
                        LookupIterator::CHECK_OWN_REAL);
      MaybeHandle<Object> maybe_prop = Object::GetProperty(&it);
      DCHECK(it.IsFound());
      DCHECK(maybe_prop.ToHandleChecked().is_identical_to(result));
  #endif
    } else {
      JSObject::AddProperty(handle(JSObject::cast(result->prototype())),
                            constructor_string(), result, DONT_ENUM);
    }
  
    // Down from here is only valid for API functions that can be used as a
    // constructor (don't set the "remove prototype" flag).
  
    Handle<Map> map(result->initial_map());
  
    // Mark as undetectable if needed.
    if (obj->undetectable()) {
      map->set_is_undetectable();
    }
  
    // Mark as hidden for the __proto__ accessor if needed.
    if (obj->hidden_prototype()) {
      map->set_is_hidden_prototype();
    }
  
    // Mark as needs_access_check if needed.
    if (obj->needs_access_check()) {
      map->set_is_access_check_needed(true);
    }
  
    // Set interceptor information in the map.
    if (!obj->named_property_handler()->IsUndefined()) {
      map->set_has_named_interceptor();
    }
    if (!obj->indexed_property_handler()->IsUndefined()) {
      map->set_has_indexed_interceptor();
    }
  
    // Set instance call-as-function information in the map.
    if (!obj->instance_call_handler()->IsUndefined()) {
      map->set_has_instance_call_handler();
    }
  
    // Recursively copy parent instance templates' accessors,
    // 'data' may be modified.
    int max_number_of_additional_properties = 0;
    int max_number_of_static_properties = 0;
    FunctionTemplateInfo* info = *obj;
    while (true) {
      if (!info->instance_template()->IsUndefined()) {
        Object* props =
            ObjectTemplateInfo::cast(
                info->instance_template())->property_accessors();
        if (!props->IsUndefined()) {
          Handle<Object> props_handle(props, isolate());
          NeanderArray props_array(props_handle);
          max_number_of_additional_properties += props_array.length();
        }
      }
      if (!info->property_accessors()->IsUndefined()) {
        Object* props = info->property_accessors();
        if (!props->IsUndefined()) {
          Handle<Object> props_handle(props, isolate());
          NeanderArray props_array(props_handle);
          max_number_of_static_properties += props_array.length();
        }
      }
      Object* parent = info->parent_template();
      if (parent->IsUndefined()) break;
      info = FunctionTemplateInfo::cast(parent);
    }
  
    Map::EnsureDescriptorSlack(map, max_number_of_additional_properties);
  
    // Use a temporary FixedArray to acculumate static accessors
    int valid_descriptors = 0;
    Handle<FixedArray> array;
    if (max_number_of_static_properties > 0) {
      array = NewFixedArray(max_number_of_static_properties);
    }
  
    while (true) {
      // Install instance descriptors
      if (!obj->instance_template()->IsUndefined()) {
        Handle<ObjectTemplateInfo> instance =
            Handle<ObjectTemplateInfo>(
                ObjectTemplateInfo::cast(obj->instance_template()), isolate());
        Handle<Object> props = Handle<Object>(instance->property_accessors(),
                                              isolate());
        if (!props->IsUndefined()) {
          Map::AppendCallbackDescriptors(map, props);
        }
      }
      // Accumulate static accessors
      if (!obj->property_accessors()->IsUndefined()) {
        Handle<Object> props = Handle<Object>(obj->property_accessors(),
                                              isolate());
        valid_descriptors =
            AccessorInfo::AppendUnique(props, array, valid_descriptors);
      }
      // Climb parent chain
      Handle<Object> parent = Handle<Object>(obj->parent_template(), isolate());
      if (parent->IsUndefined()) break;
      obj = Handle<FunctionTemplateInfo>::cast(parent);
    }
  
    // Install accumulated static accessors
    for (int i = 0; i < valid_descriptors; i++) {
      Handle<AccessorInfo> accessor(AccessorInfo::cast(array->get(i)));
      JSObject::SetAccessor(result, accessor).Assert();
    }
  
    DCHECK(result->shared()->IsApiFunction());
    return result;
  }
  
  
  Handle<MapCache> Factory::AddToMapCache(Handle<Context> context,
                                          Handle<FixedArray> keys,
                                          Handle<Map> map) {
    Handle<MapCache> map_cache = handle(MapCache::cast(context->map_cache()));
    Handle<MapCache> result = MapCache::Put(map_cache, keys, map);
    context->set_map_cache(*result);
    return result;
  }
  
  
  Handle<Map> Factory::ObjectLiteralMapFromCache(Handle<Context> context,
                                                 Handle<FixedArray> keys) {
    if (context->map_cache()->IsUndefined()) {
      // Allocate the new map cache for the native context.
      Handle<MapCache> new_cache = MapCache::New(isolate(), 24);
      context->set_map_cache(*new_cache);
    }
    // Check to see whether there is a matching element in the cache.
    Handle<MapCache> cache =
        Handle<MapCache>(MapCache::cast(context->map_cache()));
    Handle<Object> result = Handle<Object>(cache->Lookup(*keys), isolate());
    if (result->IsMap()) return Handle<Map>::cast(result);
    // Create a new map and add it to the cache.
    Handle<Map> map = Map::Create(
        handle(context->object_function()), keys->length());
    AddToMapCache(context, keys, map);
    return map;
  }
  
  
  void Factory::SetRegExpAtomData(Handle<JSRegExp> regexp,
                                  JSRegExp::Type type,
                                  Handle<String> source,
                                  JSRegExp::Flags flags,
                                  Handle<Object> data) {
    Handle<FixedArray> store = NewFixedArray(JSRegExp::kAtomDataSize);
  
    store->set(JSRegExp::kTagIndex, Smi::FromInt(type));
    store->set(JSRegExp::kSourceIndex, *source);
    store->set(JSRegExp::kFlagsIndex, Smi::FromInt(flags.value()));
    store->set(JSRegExp::kAtomPatternIndex, *data);
    regexp->set_data(*store);
  }
  
  void Factory::SetRegExpIrregexpData(Handle<JSRegExp> regexp,
                                      JSRegExp::Type type,
                                      Handle<String> source,
                                      JSRegExp::Flags flags,
                                      int capture_count) {
    Handle<FixedArray> store = NewFixedArray(JSRegExp::kIrregexpDataSize);
    Smi* uninitialized = Smi::FromInt(JSRegExp::kUninitializedValue);
    store->set(JSRegExp::kTagIndex, Smi::FromInt(type));
    store->set(JSRegExp::kSourceIndex, *source);
    store->set(JSRegExp::kFlagsIndex, Smi::FromInt(flags.value()));
    store->set(JSRegExp::kIrregexpASCIICodeIndex, uninitialized);
    store->set(JSRegExp::kIrregexpUC16CodeIndex, uninitialized);
    store->set(JSRegExp::kIrregexpASCIICodeSavedIndex, uninitialized);
    store->set(JSRegExp::kIrregexpUC16CodeSavedIndex, uninitialized);
    store->set(JSRegExp::kIrregexpMaxRegisterCountIndex, Smi::FromInt(0));
    store->set(JSRegExp::kIrregexpCaptureCountIndex,
               Smi::FromInt(capture_count));
    regexp->set_data(*store);
  }
  
  
  
  MaybeHandle<FunctionTemplateInfo> Factory::ConfigureInstance(
      Handle<FunctionTemplateInfo> desc, Handle<JSObject> instance) {
    // Configure the instance by adding the properties specified by the
    // instance template.
    Handle<Object> instance_template(desc->instance_template(), isolate());
    if (!instance_template->IsUndefined()) {
        RETURN_ON_EXCEPTION(
            isolate(),
            Execution::ConfigureInstance(isolate(), instance, instance_template),
            FunctionTemplateInfo);
    }
    return desc;
  }
  
  
  Handle<Object> Factory::GlobalConstantFor(Handle<String> name) {
    if (String::Equals(name, undefined_string())) return undefined_value();
    if (String::Equals(name, nan_string())) return nan_value();
    if (String::Equals(name, infinity_string())) return infinity_value();
    return Handle<Object>::null();
  }
  
  
  Handle<Object> Factory::ToBoolean(bool value) {
    return value ? true_value() : false_value();
  }
  
  
  } }  // namespace v8::internal
  