[parser] Inline byte scope data into PreparseData object

Each PreparseData object had at least one pointer to a PodArray for its
serialized scope data. These objects usually have only tens of bytes of
payload. By inlining the byte data we save 3 words per PreparseData object.
This optimization saves 140KB of data on cnn.com.


- Store data_length and inner_length as int32 saving a words on 64bit
- Inline store byte data into PreparseData
- OnHeapConsumedPreparseData directly uses the PreparseData object
- get_inner, set_inner no longer allow Null sentinels

Change-Id: I1f62154d05ea2f98a6574efa738b32a8a84319d5
Reviewed-on: https://chromium-review.googlesource.com/c/1406673Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58751}

src/arm64/constants-arm64.h

@@ -111,8 +111,6 @@ const unsigned kRegCodeMask = 0x1f;
 const unsigned kShiftAmountWRegMask = 0x1f;
 const unsigned kShiftAmountXRegMask = 0x3f;
 // Standard machine types defined by AAPCS64.
-const unsigned kByteSize = 8;
-const unsigned kByteSizeInBytes = kByteSize >> 3;
 const unsigned kHalfWordSize = 16;
 const unsigned kHalfWordSizeLog2 = 4;
 const unsigned kHalfWordSizeInBytes = kHalfWordSize >> 3;

src/globals.h

@@ -119,6 +119,7 @@ constexpr uint32_t kMaxUInt32 = 0xFFFFFFFFu;
 constexpr int kMinUInt32 = 0;
 
 constexpr int kUInt8Size = sizeof(uint8_t);
+constexpr int kByteSize = sizeof(byte);
 constexpr int kCharSize = sizeof(char);
 constexpr int kShortSize = sizeof(short);  // NOLINT
 constexpr int kUInt16Size = sizeof(uint16_t);

src/heap/factory.cc

@@ -2638,15 +2638,15 @@ Handle<ModuleInfo> Factory::NewModuleInfo() {
                                           ModuleInfo::kLength, TENURED);
 }
 
-Handle<PreparseData> Factory::NewPreparseData(int length) {
-  int size = PreparseData::SizeFor(length);
+Handle<PreparseData> Factory::NewPreparseData(int data_length,
+                                              int children_length) {
+  int size = PreparseData::SizeFor(data_length, children_length);
   Handle<PreparseData> result(PreparseData::cast(AllocateRawWithImmortalMap(
                                   size, TENURED, *preparse_data_map())),
                               isolate());
-  result->set_scope_data(PodArray<uint8_t>::cast(*empty_byte_array()));
-  result->set_length(length);
-  MemsetTagged(result->child_data_start(), *null_value(), length);
-
+  result->set_data_length(data_length);
+  result->set_children_length(children_length);
+  MemsetTagged(result->inner_data_start(), *null_value(), children_length);
   result->clear_padding();
   return result;
 }

src/heap/factory.h

@@ -750,7 +750,7 @@ class V8_EXPORT_PRIVATE Factory {
 
   Handle<ModuleInfo> NewModuleInfo();
 
-  Handle<PreparseData> NewPreparseData(int length);
+  Handle<PreparseData> NewPreparseData(int data_length, int children_length);
 
   Handle<UncompiledDataWithoutPreparseData>
   NewUncompiledDataWithoutPreparseData(Handle<String> inferred_name,

src/heap/object-stats.cc

@@ -401,7 +401,6 @@ class ObjectStatsCollectorImpl {
   void RecordVirtualExternalStringDetails(ExternalString script);
   void RecordVirtualSharedFunctionInfoDetails(SharedFunctionInfo info);
   void RecordVirtualJSFunctionDetails(JSFunction function);
-  void RecordVirtualPreparseDataDetails(PreparseData data);
 
   void RecordVirtualArrayBoilerplateDescription(
       ArrayBoilerplateDescription description);
@@ -650,18 +649,6 @@ void ObjectStatsCollectorImpl::RecordVirtualFeedbackVectorDetails(
   CHECK_EQ(calculated_size, vector->Size());
 }
 
-void ObjectStatsCollectorImpl::RecordVirtualPreparseDataDetails(
-    PreparseData data) {
-  if (virtual_objects_.find(data) != virtual_objects_.end()) return;
-  // Manually insert the PreparseData since we're combining the size with it's
-  // byte_data size.
-  virtual_objects_.insert(data);
-  virtual_objects_.insert(data->scope_data());
-  size_t size = data->Size() + data->scope_data()->Size();
-  DCHECK_LE(0, data->scope_data()->length());
-  stats_->RecordObjectStats(PREPARSE_DATA_TYPE, size);
-}
-
 void ObjectStatsCollectorImpl::RecordVirtualFixedArrayDetails(
     FixedArray array) {
   if (IsCowArray(array)) {
@@ -706,8 +693,6 @@ void ObjectStatsCollectorImpl::CollectStatistics(
       } else if (obj->IsArrayBoilerplateDescription()) {
         RecordVirtualArrayBoilerplateDescription(
             ArrayBoilerplateDescription::cast(obj));
-      } else if (obj->IsPreparseData()) {
-        RecordVirtualPreparseDataDetails(PreparseData::cast(obj));
       } else if (obj->IsFixedArrayExact()) {
         // Has to go last as it triggers too eagerly.
         RecordVirtualFixedArrayDetails(FixedArray::cast(obj));

src/objects-body-descriptors-inl.h

@@ -505,18 +505,21 @@ class FeedbackVector::BodyDescriptor final : public BodyDescriptorBase {
 class PreparseData::BodyDescriptor final : public BodyDescriptorBase {
  public:
   static bool IsValidSlot(Map map, HeapObject obj, int offset) {
-    return offset == kScopeDataOffset || offset >= kChildDataStartOffset;
+    return offset >= PreparseData::cast(obj)->inner_start_offset();
   }
 
   template <typename ObjectVisitor>
   static inline void IterateBody(Map map, HeapObject obj, int object_size,
                                  ObjectVisitor* v) {
-    IteratePointer(obj, kScopeDataOffset, v);
-    IteratePointers(obj, kChildDataStartOffset, object_size, v);
+    PreparseData data = PreparseData::cast(obj);
+    int start_offset = data->inner_start_offset();
+    int end_offset = start_offset + data->children_length() * kTaggedSize;
+    IteratePointers(obj, start_offset, end_offset, v);
   }
 
   static inline int SizeOf(Map map, HeapObject obj) {
-    return PreparseData::SizeFor(PreparseData::cast(obj)->length());
+    PreparseData data = PreparseData::cast(obj);
+    return PreparseData::SizeFor(data->data_length(), data->children_length());
   }
 };
 

src/objects-debug.cc

@@ -2033,13 +2033,11 @@ void StackFrameInfo::StackFrameInfoVerify(Isolate* isolate) {
 
 void PreparseData::PreparseDataVerify(Isolate* isolate) {
   CHECK(IsPreparseData());
-  CHECK(scope_data()->IsByteArray());
-  CHECK_GE(length(), 0);
+  CHECK_LE(0, data_length());
+  CHECK_LE(0, children_length());
 
-  for (int i = 0; i < length(); ++i) {
-    Object child = child_data(i);
-    CHECK(child->IsPreparseData() || child->IsNull());
-    VerifyPointer(isolate, child);
+  for (int i = 0; i < children_length(); ++i) {
+    VerifyPointer(isolate, get_child(i));
   }
 }
 

src/objects-inl.h

@@ -1084,7 +1084,8 @@ int HeapObject::SizeFromMap(Map map) const {
     return BigInt::SizeFor(BigInt::unchecked_cast(*this)->length());
   }
   if (instance_type == PREPARSE_DATA_TYPE) {
-    return PreparseData::SizeFor(PreparseData::unchecked_cast(*this)->length());
+    PreparseData data = PreparseData::unchecked_cast(*this);
+    return PreparseData::SizeFor(data->data_length(), data->children_length());
   }
   if (instance_type == CODE_TYPE) {
     return Code::unchecked_cast(*this)->CodeSize();

src/objects-printer.cc

@@ -2252,10 +2252,10 @@ void LayoutDescriptor::Print(std::ostream& os) {  // NOLINT
 
 void PreparseData::PreparseDataPrint(std::ostream& os) {  // NOLINT
   PrintHeader(os, "PreparseData");
-  os << "\n - scope_data: " << Brief(scope_data());
-  os << "\n - length: " << length();
-  for (int i = 0; i < length(); ++i) {
-    os << "\n - [" << i << "]: " << Brief(child_data(i));
+  os << "\n - data_length: " << data_length();
+  os << "\n - children_length: " << children_length();
+  for (int i = 0; i < children_length(); ++i) {
+    os << "\n - [" << i << "]: " << Brief(get_child(i));
   }
   os << "\n";
 }

src/objects.cc

@@ -3600,7 +3600,8 @@ void HeapObject::HeapObjectShortPrint(std::ostream& os) {  // NOLINT
 
     case PREPARSE_DATA_TYPE: {
       PreparseData data = PreparseData::cast(*this);
-      os << "<PreparseData[" << data->length() << "]>";
+      os << "<PreparseData[data=" << data->data_length()
+         << " children=" << data->children_length() << "]>";
       break;
     }
 

src/objects/shared-function-info-inl.h

@@ -24,35 +24,61 @@ namespace internal {
 OBJECT_CONSTRUCTORS_IMPL(PreparseData, HeapObject)
 
 CAST_ACCESSOR(PreparseData)
-ACCESSORS(PreparseData, scope_data, PodArray<uint8_t>, kScopeDataOffset)
-INT_ACCESSORS(PreparseData, length, kLengthOffset)
+INT_ACCESSORS(PreparseData, data_length, kDataLengthOffset)
+INT_ACCESSORS(PreparseData, children_length, kInnerLengthOffset)
 
-Object PreparseData::child_data(int index) const {
-  DCHECK_GE(index, 0);
-  DCHECK_LT(index, this->length());
-  int offset = kChildDataStartOffset + index * kTaggedSize;
-  return RELAXED_READ_FIELD(*this, offset);
+int PreparseData::inner_start_offset() const {
+  return InnerOffset(data_length());
 }
 
-void PreparseData::set_child_data(int index, Object value,
-                                  WriteBarrierMode mode) {
-  DCHECK_GE(index, 0);
-  DCHECK_LT(index, this->length());
-  int offset = kChildDataStartOffset + index * kTaggedSize;
-  RELAXED_WRITE_FIELD(*this, offset, value);
-  CONDITIONAL_WRITE_BARRIER(*this, offset, value, mode);
+ObjectSlot PreparseData::inner_data_start() const {
+  return RawField(inner_start_offset());
 }
 
-ObjectSlot PreparseData::child_data_start() const {
-  return RawField(kChildDataStartOffset);
+void PreparseData::clear_padding() {
+  int data_end_offset = kDataStartOffset + data_length();
+  int padding_size = inner_start_offset() - data_end_offset;
+  DCHECK_LE(0, padding_size);
+  if (padding_size == 0) return;
+  memset(reinterpret_cast<void*>(address() + data_end_offset), 0, padding_size);
 }
 
-void PreparseData::clear_padding() {
-  if (FIELD_SIZE(kOptionalPaddingOffset) != 0) {
-    DCHECK_EQ(4, FIELD_SIZE(kOptionalPaddingOffset));
-    memset(reinterpret_cast<void*>(address() + kOptionalPaddingOffset), 0,
-           FIELD_SIZE(kOptionalPaddingOffset));
-  }
+byte PreparseData::get(int index) const {
+  DCHECK_LE(0, index);
+  DCHECK_LT(index, data_length());
+  int offset = kDataStartOffset + index * kByteSize;
+  return READ_BYTE_FIELD(*this, offset);
+}
+
+void PreparseData::set(int index, byte value) {
+  DCHECK_LE(0, index);
+  DCHECK_LT(index, data_length());
+  int offset = kDataStartOffset + index * kByteSize;
+  WRITE_BYTE_FIELD(*this, offset, value);
+}
+
+void PreparseData::copy_in(int index, const byte* buffer, int length) {
+  DCHECK(index >= 0 && length >= 0 && length <= kMaxInt - index &&
+         index + length <= this->data_length());
+  Address dst_addr = FIELD_ADDR(this, kDataStartOffset + index * kByteSize);
+  memcpy(reinterpret_cast<void*>(dst_addr), buffer, length);
+}
+
+PreparseData PreparseData::get_child(int index) const {
+  DCHECK_LE(0, index);
+  DCHECK_LT(index, this->children_length());
+  int offset = inner_start_offset() + index * kTaggedSize;
+  Object result = RELAXED_READ_FIELD(*this, offset);
+  return PreparseData::cast(result);
+}
+
+void PreparseData::set_child(int index, PreparseData value,
+                             WriteBarrierMode mode) {
+  DCHECK_LE(0, index);
+  DCHECK_LT(index, this->children_length());
+  int offset = inner_start_offset() + index * kTaggedSize;
+  RELAXED_WRITE_FIELD(*this, offset, value);
+  CONDITIONAL_WRITE_BARRIER(*this, offset, value, mode);
 }
 
 OBJECT_CONSTRUCTORS_IMPL(UncompiledData, HeapObject)
@@ -65,11 +91,10 @@ INT32_ACCESSORS(UncompiledData, end_position, kEndPositionOffset)
 INT32_ACCESSORS(UncompiledData, function_literal_id, kFunctionLiteralIdOffset)
 
 void UncompiledData::clear_padding() {
-  if (FIELD_SIZE(kOptionalPaddingOffset) != 0) {
-    DCHECK_EQ(4, FIELD_SIZE(kOptionalPaddingOffset));
-    memset(reinterpret_cast<void*>(address() + kOptionalPaddingOffset), 0,
-           FIELD_SIZE(kOptionalPaddingOffset));
-  }
+  if (FIELD_SIZE(kOptionalPaddingOffset) == 0) return;
+  DCHECK_EQ(4, FIELD_SIZE(kOptionalPaddingOffset));
+  memset(reinterpret_cast<void*>(address() + kOptionalPaddingOffset), 0,
+         FIELD_SIZE(kOptionalPaddingOffset));
 }
 
 CAST_ACCESSOR(UncompiledDataWithoutPreparseData)

src/objects/shared-function-info.h

@@ -27,16 +27,37 @@ class WasmExportedFunctionData;
 
 // Data collected by the pre-parser storing information about scopes and inner
 // functions.
+//
+// PreparseData Layout:
+// +-------------------------------+
+// | data_length | children_length |
+// +-------------------------------+
+// | Scope Byte Data ...           |
+// | ...                           |
+// +-------------------------------+
+// | [Padding]                     |
+// +-------------------------------+
+// | Inner PreparseData 1          |
+// +-------------------------------+
+// | ...                           |
+// +-------------------------------+
+// | Inner PreparseData N          |
+// +-------------------------------+
 class PreparseData : public HeapObject {
  public:
-  DECL_ACCESSORS(scope_data, PodArray<uint8_t>)
-  DECL_INT_ACCESSORS(length)
+  DECL_INT_ACCESSORS(data_length)
+  DECL_INT_ACCESSORS(children_length)
 
-  inline Object child_data(int index) const;
-  inline void set_child_data(int index, Object value,
-                             WriteBarrierMode mode = UPDATE_WRITE_BARRIER);
+  inline int inner_start_offset() const;
+  inline ObjectSlot inner_data_start() const;
 
-  inline ObjectSlot child_data_start() const;
+  inline byte get(int index) const;
+  inline void set(int index, byte value);
+  inline void copy_in(int index, const byte* buffer, int length);
+
+  inline PreparseData get_child(int index) const;
+  inline void set_child(int index, PreparseData value,
+                        WriteBarrierMode mode = UPDATE_WRITE_BARRIER);
 
   // Clear uninitialized padding space.
   inline void clear_padding();
@@ -46,20 +67,24 @@ class PreparseData : public HeapObject {
   DECL_VERIFIER(PreparseData)
 
 // Layout description.
-#define PREPARSE_DATA_FIELDS(V)                                           \
-  V(kScopeDataOffset, kTaggedSize)                                        \
-  V(kLengthOffset, kIntSize)                                              \
-  V(kOptionalPaddingOffset, POINTER_SIZE_PADDING(kOptionalPaddingOffset)) \
-  /* Header size. */                                                      \
-  V(kChildDataStartOffset, 0)
+#define PREPARSE_DATA_FIELDS(V)     \
+  V(kDataLengthOffset, kInt32Size)  \
+  V(kInnerLengthOffset, kInt32Size) \
+  /* Header size. */                \
+  V(kDataStartOffset, 0)            \
+  V(kHeaderSize, 0)
 
   DEFINE_FIELD_OFFSET_CONSTANTS(HeapObject::kHeaderSize, PREPARSE_DATA_FIELDS)
 #undef PREPARSE_DATA_FIELDS
 
   class BodyDescriptor;
 
-  static constexpr int SizeFor(int length) {
-    return kChildDataStartOffset + length * kTaggedSize;
+  static int InnerOffset(int data_length) {
+    return RoundUp(kDataStartOffset + data_length * kByteSize, kTaggedSize);
+  }
+
+  static int SizeFor(int data_length, int children_length) {
+    return InnerOffset(data_length) + children_length * kTaggedSize;
   }
 
   OBJECT_CONSTRUCTORS(PreparseData, HeapObject);
@@ -84,7 +109,6 @@ class UncompiledData : public HeapObject {
               [](HeapObject object, ObjectSlot slot, HeapObject target) {});
 
   // Layout description.
-
 #define UNCOMPILED_DATA_FIELDS(V)                                         \
   V(kStartOfPointerFieldsOffset, 0)                                       \
   V(kInferredNameOffset, kTaggedSize)                                     \

src/parsing/preparse-data-impl.h

@@ -47,7 +47,7 @@ class PreparseDataBuilder::ByteData : public ZoneObject,
   void OverwriteFirstUint32(uint32_t data);
 #endif
 
-  Handle<PodArray<uint8_t>> Serialize(Isolate* isolate);
+  void StoreInto(PreparseData data);
 
   size_t size() const { return backing_store_.size(); }
 
@@ -60,6 +60,21 @@ class PreparseDataBuilder::ByteData : public ZoneObject,
   ZoneChunkList<uint8_t> backing_store_;
 };
 
+// Wraps a ZoneVector<uint8_t> to have with functions named the same as
+// PodArray<uint8_t>.
+class ZoneVectorWrapper {
+ public:
+  ZoneVectorWrapper() = default;
+  explicit ZoneVectorWrapper(ZoneVector<uint8_t>* data) : data_(data) {}
+
+  int data_length() const { return static_cast<int>(data_->size()); }
+
+  uint8_t get(int index) const { return data_->at(index); }
+
+ private:
+  ZoneVector<uint8_t>* data_ = nullptr;
+};
+
 template <class Data>
 class BaseConsumedPreparseData : public ConsumedPreparseData {
  public:
@@ -93,19 +108,19 @@ class BaseConsumedPreparseData : public ConsumedPreparseData {
     };
 
     void SetPosition(int position) {
-      DCHECK_LE(position, data_.length());
+      DCHECK_LE(position, data_.data_length());
       index_ = position;
     }
 
     size_t RemainingBytes() const {
       DCHECK(has_data_);
-      DCHECK_LE(index_, data_.length());
-      return data_.length() - index_;
+      DCHECK_LE(index_, data_.data_length());
+      return data_.data_length() - index_;
     }
 
     bool HasRemainingBytes(size_t bytes) const {
       DCHECK(has_data_);
-      return index_ <= data_.length() && bytes <= RemainingBytes();
+      return index_ <= data_.data_length() && bytes <= RemainingBytes();
     }
 
     int32_t ReadUint32() {
@@ -188,33 +203,18 @@ class BaseConsumedPreparseData : public ConsumedPreparseData {
 
 // Implementation of ConsumedPreparseData for on-heap data.
 class OnHeapConsumedPreparseData final
-    : public BaseConsumedPreparseData<PodArray<uint8_t>> {
+    : public BaseConsumedPreparseData<PreparseData> {
  public:
   OnHeapConsumedPreparseData(Isolate* isolate, Handle<PreparseData> data);
 
-  PodArray<uint8_t> GetScopeData() final;
-  ProducedPreparseData* GetChildData(Zone* zone, int child_index) final;
+  PreparseData GetScopeData() final;
+  ProducedPreparseData* GetChildData(Zone* zone, int index) final;
 
  private:
   Isolate* isolate_;
   Handle<PreparseData> data_;
 };
 
-// Wraps a ZoneVector<uint8_t> to have with functions named the same as
-// PodArray<uint8_t>.
-class ZoneVectorWrapper {
- public:
-  ZoneVectorWrapper() = default;
-  explicit ZoneVectorWrapper(ZoneVector<uint8_t>* data) : data_(data) {}
-
-  int length() const { return static_cast<int>(data_->size()); }
-
-  uint8_t get(int index) const { return data_->at(index); }
-
- private:
-  ZoneVector<uint8_t>* data_ = nullptr;
-};
-
 // A serialized PreparseData in zone memory (as apposed to being on-heap).
 class ZonePreparseData : public ZoneObject {
  public:

src/parsing/preparse-data.cc

@@ -135,19 +135,12 @@ void PreparseDataBuilder::ByteData::WriteQuarter(uint8_t data) {
   backing_store_.back() |= (data << shift_amount);
 }
 
-Handle<PodArray<uint8_t>> PreparseDataBuilder::ByteData::Serialize(
-    Isolate* isolate) {
-  Handle<PodArray<uint8_t>> array = PodArray<uint8_t>::New(
-      isolate, static_cast<int>(backing_store_.size()), TENURED);
-
+void PreparseDataBuilder::ByteData::StoreInto(PreparseData data) {
   DisallowHeapAllocation no_gc;
-  PodArray<uint8_t> raw_array = *array;
-
   int i = 0;
   for (uint8_t item : backing_store_) {
-    raw_array->set(i++, item);
+    data->set(i++, item);
   }
-  return array;
 }
 
 PreparseDataBuilder::PreparseDataBuilder(Zone* zone,
@@ -252,17 +245,15 @@ Handle<PreparseData> PreparseDataBuilder::Serialize(Isolate* isolate) {
   DCHECK(!ThisOrParentBailedOut());
 
   int child_data_length = static_cast<int>(data_for_inner_functions_.size());
-  Handle<PreparseData> data =
-      isolate->factory()->NewPreparseData(child_data_length);
-
-  Handle<PodArray<uint8_t>> scope_data_array = byte_data_->Serialize(isolate);
-  data->set_scope_data(*scope_data_array);
+  Handle<PreparseData> data = isolate->factory()->NewPreparseData(
+      static_cast<int>(byte_data_->size()), child_data_length);
+  byte_data_->StoreInto(*data);
 
   int i = 0;
   for (const auto& item : data_for_inner_functions_) {
     DCHECK_NOT_NULL(item);
     Handle<PreparseData> child_data = item->Serialize(isolate);
-    data->set_child_data(i++, *child_data);
+    data->set_child(i++, *child_data);
   }
 
   return data;
@@ -588,25 +579,18 @@ void BaseConsumedPreparseData<Data>::VerifyDataStart() {
 }
 #endif
 
-PodArray<uint8_t> OnHeapConsumedPreparseData::GetScopeData() {
-  return data_->scope_data();
-}
+PreparseData OnHeapConsumedPreparseData::GetScopeData() { return *data_; }
 
-ProducedPreparseData* OnHeapConsumedPreparseData::GetChildData(
-    Zone* zone, int child_index) {
-  CHECK_GT(data_->length(), child_index);
-  Object child_data = data_->child_data(child_index);
-  if (!child_data->IsPreparseData()) return nullptr;
-  Handle<PreparseData> child_data_handle(PreparseData::cast(child_data),
-                                         isolate_);
+ProducedPreparseData* OnHeapConsumedPreparseData::GetChildData(Zone* zone,
+                                                               int index) {
+  DisallowHeapAllocation no_gc;
+  Handle<PreparseData> child_data_handle(data_->get_child(index), isolate_);
   return ProducedPreparseData::For(child_data_handle, zone);
 }
 
 OnHeapConsumedPreparseData::OnHeapConsumedPreparseData(
     Isolate* isolate, Handle<PreparseData> data)
-    : BaseConsumedPreparseData<PodArray<uint8_t>>(),
-      isolate_(isolate),
-      data_(data) {
+    : BaseConsumedPreparseData<PreparseData>(), isolate_(isolate), data_(data) {
   DCHECK_NOT_NULL(isolate);
   DCHECK(data->IsPreparseData());
 #ifdef DEBUG
@@ -621,22 +605,17 @@ ZonePreparseData::ZonePreparseData(Zone* zone,
       children_(child_length, zone) {}
 
 Handle<PreparseData> ZonePreparseData::Serialize(Isolate* isolate) {
+  int data_size = static_cast<int>(byte_data()->size());
   int child_data_length = child_length();
   Handle<PreparseData> result =
-      isolate->factory()->NewPreparseData(child_data_length);
-
-  Handle<PodArray<uint8_t>> scope_data_array = PodArray<uint8_t>::New(
-      isolate, static_cast<int>(byte_data()->size()), TENURED);
-  scope_data_array->copy_in(0, byte_data()->data(),
-                            static_cast<int>(byte_data()->size()));
-  result->set_scope_data(*scope_data_array);
+      isolate->factory()->NewPreparseData(data_size, child_data_length);
+  result->copy_in(0, byte_data()->data(), data_size);
 
   for (int i = 0; i < child_data_length; i++) {
     ZonePreparseData* child = get_child(i);
-    if (child) {
-      Handle<PreparseData> child_data = child->Serialize(isolate);
-      result->set_child_data(i, *child_data);
-    }
+    DCHECK_NOT_NULL(child);
+    Handle<PreparseData> child_data = child->Serialize(isolate);
+    result->set_child(i, *child_data);
   }
   return result;
 }

test/cctest/parsing/test-preparser.cc

@@ -862,7 +862,9 @@ TEST(ProducingAndConsumingByteData) {
 
   {
     // Serialize as an OnHeapConsumedPreparseData, and read back data.
-    i::Handle<i::PodArray<uint8_t>> data_on_heap = bytes.Serialize(isolate);
+    i::Handle<i::PreparseData> data_on_heap =
+        isolate->factory()->NewPreparseData(static_cast<int>(bytes.size()), 0);
+    bytes.StoreInto(*data_on_heap);
     i::OnHeapConsumedPreparseData::ByteData bytes_for_reading;
     i::OnHeapConsumedPreparseData::ByteData::ReadingScope reading_scope(
         &bytes_for_reading, *data_on_heap);