[parser] Minor cleanup PreParsedScopeDataBuilder

- Mark Serialize method as non-virtual
- Use simple scheme to mask out bytes when de-/serializing Uint32

- Improve ByteArray::ByteArrayPrint method

Drive-by-fix: 
Change-Id: I9a6779587c0a031bcf23e4f431d17026b83a808d
Reviewed-on: https://chromium-review.googlesource.com/c/1387493Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58428}

src/objects-printer.cc

@@ -444,8 +444,10 @@ void HeapObject::HeapObjectPrint(std::ostream& os) {  // NOLINT
 }
 
 void ByteArray::ByteArrayPrint(std::ostream& os) {  // NOLINT
-  os << "byte array, data starts at "
-     << static_cast<void*>(GetDataStartAddress());
+  PrintHeader(os, "ByteArray");
+  os << "\n - length: " << length()
+     << "\n - data-start: " << static_cast<void*>(GetDataStartAddress())
+     << "\n";
 }
 
 void BytecodeArray::BytecodeArrayPrint(std::ostream& os) {  // NOLINT

src/parsing/preparsed-scope-data-impl.h

@@ -105,11 +105,10 @@ class BaseConsumedPreParsedScopeData : public ConsumedPreParsedScopeData {
       DCHECK_GE(RemainingBytes(), kUint32Size);
       // Check that there indeed is an integer following.
       DCHECK_EQ(data_.get(index_++), kUint32Size);
-      int32_t result = 0;
-      byte* p = reinterpret_cast<byte*>(&result);
-      for (int i = 0; i < 4; ++i) {
-        *p++ = data_.get(index_++);
-      }
+      int32_t result = data_.get(index_) + (data_.get(index_ + 1) << 8) +
+                       (data_.get(index_ + 2) << 16) +
+                       (data_.get(index_ + 3) << 24);
+      index_ += 4;
       stored_quarters_ = 0;
       return result;
     }
@@ -216,8 +215,7 @@ class ZoneVectorWrapper {
 class ZonePreParsedScopeData : public ZoneObject {
  public:
   ZonePreParsedScopeData(Zone* zone,
-                         ZoneChunkList<uint8_t>::iterator byte_data_begin,
-                         ZoneChunkList<uint8_t>::iterator byte_data_end,
+                         PreParsedScopeDataBuilder::ByteData* byte_data,
                          int child_length);
 
   Handle<PreParsedScopeData> Serialize(Isolate* isolate);

src/parsing/preparsed-scope-data.cc

@@ -83,10 +83,10 @@ void PreParsedScopeDataBuilder::ByteData::WriteUint32(uint32_t data) {
   // Save expected item size in debug mode.
   backing_store_.push_back(kUint32Size);
 #endif
-  const uint8_t* d = reinterpret_cast<uint8_t*>(&data);
-  for (int i = 0; i < 4; ++i) {
-    backing_store_.push_back(*d++);
-  }
+  backing_store_.push_back(data & 0xFF);
+  backing_store_.push_back((data >> 8) & 0xFF);
+  backing_store_.push_back((data >> 16) & 0xFF);
+  backing_store_.push_back((data >> 24) & 0xFF);
   free_quarters_in_last_byte_ = 0;
 }
 
@@ -97,10 +97,10 @@ void PreParsedScopeDataBuilder::ByteData::OverwriteFirstUint32(uint32_t data) {
   DCHECK_GE(backing_store_.size(), kUint32Size);
   DCHECK_EQ(*it, kUint32Size);
   ++it;
-  const uint8_t* d = reinterpret_cast<uint8_t*>(&data);
-  for (size_t i = 0; i < 4; ++i) {
-    *it++ = *d++;
-  }
+  *it++ = data & 0xFF;
+  *it++ = (data >> 8) & 0xFF;
+  *it++ = (data >> 16) & 0xFF;
+  *it++ = (data >> 24) & 0xFF;
 }
 #endif
 
@@ -209,14 +209,12 @@ void PreParsedScopeDataBuilder::SaveScopeAllocationData(
 
   if (bailed_out_) return;
 
-  uint32_t scope_data_start = static_cast<uint32_t>(byte_data_->size());
 
   // If there are no skippable inner functions, we don't need to save anything.
-  if (scope_data_start == ByteData::kPlaceholderSize) {
-    return;
-  }
+  if (!ContainsInnerFunctions()) return;
 
 #ifdef DEBUG
+  uint32_t scope_data_start = static_cast<uint32_t>(byte_data_->size());
   byte_data_->OverwriteFirstUint32(scope_data_start);
 
   // For a data integrity check, write a value between data about skipped inner
@@ -239,7 +237,7 @@ MaybeHandle<PreParsedScopeData> PreParsedScopeDataBuilder::Serialize(
 
   DCHECK(!ThisOrParentBailedOut());
 
-  if (byte_data_->size() <= ByteData::kPlaceholderSize) {
+  if (!ContainsInnerFunctions()) {
     // The data contains only the placeholder.
     return MaybeHandle<PreParsedScopeData>();
   }
@@ -270,14 +268,11 @@ ZonePreParsedScopeData* PreParsedScopeDataBuilder::Serialize(Zone* zone) {
 
   DCHECK(!ThisOrParentBailedOut());
 
-  if (byte_data_->size() <= ByteData::kPlaceholderSize) {
-    // The data contains only the placeholder.
-    return nullptr;
-  }
+  if (!ContainsInnerFunctions()) return nullptr;
 
   int child_length = static_cast<int>(data_for_inner_functions_.size());
-  ZonePreParsedScopeData* result = new (zone) ZonePreParsedScopeData(
-      zone, byte_data_->begin(), byte_data_->end(), child_length);
+  ZonePreParsedScopeData* result =
+      new (zone) ZonePreParsedScopeData(zone, byte_data_, child_length);
 
   int i = 0;
   for (const auto& item : data_for_inner_functions_) {
@@ -628,9 +623,9 @@ OnHeapConsumedPreParsedScopeData::OnHeapConsumedPreParsedScopeData(
 }
 
 ZonePreParsedScopeData::ZonePreParsedScopeData(
-    Zone* zone, ZoneChunkList<uint8_t>::iterator byte_data_begin,
-    ZoneChunkList<uint8_t>::iterator byte_data_end, int child_length)
-    : byte_data_(byte_data_begin, byte_data_end, zone),
+    Zone* zone, PreParsedScopeDataBuilder::ByteData* byte_data,
+    int child_length)
+    : byte_data_(byte_data->begin(), byte_data->end(), zone),
       children_(child_length, zone) {}
 
 Handle<PreParsedScopeData> ZonePreParsedScopeData::Serialize(Isolate* isolate) {

src/parsing/preparsed-scope-data.h

@@ -126,8 +126,8 @@ class PreParsedScopeDataBuilder : public ZoneObject {
  private:
   friend class BuilderProducedPreParsedScopeData;
 
-  virtual MaybeHandle<PreParsedScopeData> Serialize(Isolate* isolate);
-  virtual ZonePreParsedScopeData* Serialize(Zone* zone);
+  MaybeHandle<PreParsedScopeData> Serialize(Isolate* isolate);
+  ZonePreParsedScopeData* Serialize(Zone* zone);
 
   void SaveDataForScope(Scope* scope);
   void SaveDataForVariable(Variable* var);

test/cctest/parsing/test-preparser.cc

@@ -840,8 +840,7 @@ TEST(ProducingAndConsumingByteData) {
 
   {
     // Serialize as a ZoneConsumedPreParsedScopeData, and read back data.
-    i::ZonePreParsedScopeData zone_serialized(&zone, bytes.begin(), bytes.end(),
-                                              0);
+    i::ZonePreParsedScopeData zone_serialized(&zone, &bytes, 0);
     i::ZoneConsumedPreParsedScopeData::ByteData bytes_for_reading;
     i::ZoneVectorWrapper wrapper(zone_serialized.byte_data());
     i::ZoneConsumedPreParsedScopeData::ByteData::ReadingScope reading_scope(