Serializer: commit new internalized strings after deserialization.

src/snapshot/serialize.cc

 // Copyright 2012 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/v8.h"
 
 #include "src/accessors.h"
 #include "src/api.h"
 #include "src/base/platform/platform.h"
 #include "src/bootstrapper.h"
@@ skipping 624 matching lines @@
 }
 
 
 MaybeHandle<SharedFunctionInfo> Deserializer::DeserializeCode(
     Isolate* isolate) {
   Initialize(isolate);
   if (!ReserveSpace()) {
     return Handle<SharedFunctionInfo>();
   } else {
     deserializing_user_code_ = true;
-    DisallowHeapAllocation no_gc;
-    Object* root;
-    VisitPointer(&root);
-    DeserializeDeferredObjects();
-    return Handle<SharedFunctionInfo>(SharedFunctionInfo::cast(root));
+    HandleScope scope(isolate);
+    Handle<SharedFunctionInfo> result;
+    {
+      DisallowHeapAllocation no_gc;
+      Object* root;
+      VisitPointer(&root);
+      DeserializeDeferredObjects();
+      result = Handle<SharedFunctionInfo>(SharedFunctionInfo::cast(root));
+    }
+    CommitNewInternalizedStrings(isolate);
+    return scope.CloseAndEscape(result);
   }
 }
 
 
 Deserializer::~Deserializer() {
   // TODO(svenpanne) Re-enable this assertion when v8 initialization is fixed.
   // DCHECK(source_.AtEOF());
   attached_objects_.Dispose();
 }
 
@@ skipping 44 matching lines @@
   uint32_t Hash() override { return hash_; }
 
   uint32_t HashForObject(Object* key) override {
     return String::cast(key)->Hash();
   }
 
   MUST_USE_RESULT virtual Handle<Object> AsHandle(Isolate* isolate) override {
     return handle(string_, isolate);
   }
 
+ private:
   String* string_;
   uint32_t hash_;
+  DisallowHeapAllocation no_gc;
 };
 
 
 HeapObject* Deserializer::PostProcessNewObject(HeapObject* obj, int space) {
   if (deserializing_user_code()) {
     if (obj->IsString()) {
       String* string = String::cast(obj);
       // Uninitialize hash field as the hash seed may have changed.
       string->set_hash_field(String::kEmptyHashField);
       if (string->IsInternalizedString()) {
         // Canonicalize the internalized string. If it already exists in the
         // string table, set it to forward to the existing one.
-        DisallowHeapAllocation no_gc;
-        HandleScope scope(isolate_);
         StringTableInsertionKey key(string);
-        String* canonical = *StringTable::LookupKey(isolate_, &key);
-        string->SetForwardedInternalizedString(canonical);
-        return canonical;
+        String* canonical = StringTable::LookupKeyIfExists(isolate_, &key);
+        if (canonical == NULL) {
+          new_internalized_strings_.Add(handle(string));
+          return string;
+        } else {
+          string->SetForwardedInternalizedString(canonical);
+          return canonical;
+        }
       }
     } else if (obj->IsScript()) {
       // Assign a new script id to avoid collision.
       Script::cast(obj)->set_id(isolate_->heap()->NextScriptId());
     } else {
       DCHECK(CanBeDeferred(obj));
     }
   }
   if (obj->IsAllocationSite()) {
     DCHECK(obj->IsAllocationSite());
@@ skipping 16 matching lines @@
     if (deserializing_user_code() || space == LO_SPACE) {
       new_code_objects_.Add(Code::cast(obj));
     }
   }
   // Check alignment.
   DCHECK_EQ(0, Heap::GetFillToAlign(obj->address(), obj->RequiredAlignment()));
   return obj;
 }
 
 
+void Deserializer::CommitNewInternalizedStrings(Isolate* isolate) {
+  StringTable::EnsureCapacityForDeserialization(
+      isolate, new_internalized_strings_.length());
+  for (Handle<String> string : new_internalized_strings_) {
+    StringTableInsertionKey key(*string);
+    DCHECK_NULL(StringTable::LookupKeyIfExists(isolate, &key));
+    StringTable::LookupKey(isolate, &key);
+  }
+}
+
+
 HeapObject* Deserializer::GetBackReferencedObject(int space) {
   HeapObject* obj;
   BackReference back_reference(source_.GetInt());
   if (space == LO_SPACE) {
     CHECK(back_reference.chunk_index() == 0);
     uint32_t index = back_reference.large_object_index();
     obj = deserialized_large_objects_[index];
   } else {
     DCHECK(space < kNumberOfPreallocatedSpaces);
     uint32_t chunk_index = back_reference.chunk_index();
@@ skipping 1561 matching lines @@
   // We expect no instantiated function objects or contexts.
   CHECK(!obj->IsJSFunction() && !obj->IsContext());
 
   SerializeGeneric(obj, how_to_code, where_to_point);
 }
 
 
 void CodeSerializer::SerializeGeneric(HeapObject* heap_object,
                                       HowToCode how_to_code,
                                       WhereToPoint where_to_point) {
-  if (heap_object->IsInternalizedString()) num_internalized_strings_++;
-
   // Object has not yet been serialized.  Serialize it here.
   ObjectSerializer serializer(this, heap_object, sink_, how_to_code,
                               where_to_point);
   serializer.Serialize();
 }
 
 
 void CodeSerializer::SerializeBuiltin(int builtin_index, HowToCode how_to_code,
                                       WhereToPoint where_to_point) {
   DCHECK((how_to_code == kPlain && where_to_point == kStartOfObject) ||
@@ skipping 101 matching lines @@
   // Prepare and register list of attached objects.
   Vector<const uint32_t> code_stub_keys = scd->CodeStubKeys();
   Vector<Handle<Object> > attached_objects = Vector<Handle<Object> >::New(
       code_stub_keys.length() + kCodeStubsBaseIndex);
   attached_objects[kSourceObjectIndex] = source;
   for (int i = 0; i < code_stub_keys.length(); i++) {
     attached_objects[i + kCodeStubsBaseIndex] =
         CodeStub::GetCode(isolate, code_stub_keys[i]).ToHandleChecked();
   }
 
-  // Eagerly expand string table to avoid allocations during deserialization.
-  StringTable::EnsureCapacityForDeserialization(isolate,
-                                                scd->NumInternalizedStrings());
-
   Deserializer deserializer(scd.get());
   deserializer.SetAttachedObjects(attached_objects);
 
   // Deserialize.
   Handle<SharedFunctionInfo> result;
   if (!deserializer.DeserializeCode(isolate).ToHandle(&result)) {
     // Deserializing may fail if the reservations cannot be fulfilled.
     if (FLAG_profile_deserialization) PrintF("[Deserializing failed]\n");
     return MaybeHandle<SharedFunctionInfo>();
   }
@@ skipping 138 matching lines @@
   // Allocate backing store and create result data.
   AllocateData(size);
 
   // Set header values.
   SetMagicNumber(cs.isolate());
   SetHeaderValue(kVersionHashOffset, Version::Hash());
   SetHeaderValue(kSourceHashOffset, SourceHash(cs.source()));
   SetHeaderValue(kCpuFeaturesOffset,
                  static_cast<uint32_t>(CpuFeatures::SupportedFeatures()));
   SetHeaderValue(kFlagHashOffset, FlagList::Hash());
-  SetHeaderValue(kNumInternalizedStringsOffset, cs.num_internalized_strings());
   SetHeaderValue(kNumReservationsOffset, reservations.length());
   SetHeaderValue(kNumCodeStubKeysOffset, num_stub_keys);
   SetHeaderValue(kPayloadLengthOffset, payload.length());
 
   Checksum checksum(payload.ToConstVector());
   SetHeaderValue(kChecksum1Offset, checksum.a());
   SetHeaderValue(kChecksum2Offset, checksum.b());
 
   // Copy reservation chunk sizes.
   CopyBytes(data_ + kHeaderSize, reinterpret_cast<byte*>(reservations.begin()),
@@ skipping 57 matching lines @@
   int payload_offset = kHeaderSize + reservations_size + code_stubs_size;
   int padded_payload_offset = POINTER_SIZE_ALIGN(payload_offset);
   const byte* payload = data_ + padded_payload_offset;
   DCHECK(IsAligned(reinterpret_cast<intptr_t>(payload), kPointerAlignment));
   int length = GetHeaderValue(kPayloadLengthOffset);
   DCHECK_EQ(data_ + size_, payload + length);
   return Vector<const byte>(payload, length);
 }
 
 
-int SerializedCodeData::NumInternalizedStrings() const {
-  return GetHeaderValue(kNumInternalizedStringsOffset);
-}
-
 Vector<const uint32_t> SerializedCodeData::CodeStubKeys() const {
   int reservations_size = GetHeaderValue(kNumReservationsOffset) * kInt32Size;
   const byte* start = data_ + kHeaderSize + reservations_size;
   return Vector<const uint32_t>(reinterpret_cast<const uint32_t*>(start),
                                 GetHeaderValue(kNumCodeStubKeysOffset));
 }
 
 
 SerializedCodeData::SerializedCodeData(ScriptData* data)
     : SerializedData(const_cast<byte*>(data->data()), data->length()) {}
 
 
 SerializedCodeData* SerializedCodeData::FromCachedData(Isolate* isolate,
                                                        ScriptData* cached_data,
                                                        String* source) {
   DisallowHeapAllocation no_gc;
   SerializedCodeData* scd = new SerializedCodeData(cached_data);
   SanityCheckResult r = scd->SanityCheck(isolate, source);
   if (r == CHECK_SUCCESS) return scd;
   cached_data->Reject();
   source->GetIsolate()->counters()->code_cache_reject_reason()->AddSample(r);
   delete scd;
   return NULL;
 }
 }  // namespace internal
 }  // namespace v8