Changes to set up the object tag bits

vm/raw_object_snapshot.cc

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/bigint_operations.h"
 #include "vm/object.h"
 #include "vm/object_store.h"
 #include "vm/snapshot.h"
 #include "vm/visitor.h"
 
 namespace dart {
 
 static RawSmi* GetSmi(intptr_t value) {
   ASSERT((value & kSmiTagMask) == 0);
   return reinterpret_cast<RawSmi*>(value);
 }
 
 
 static uword ZoneAllocator(intptr_t size) {
   Zone* zone = Isolate::Current()->current_zone();
   return zone->Allocate(size);
 }
 
 
 RawClass* Class::ReadFrom(SnapshotReader* reader,
                           intptr_t object_id,
+                          intptr_t tags,
                           Snapshot::Kind kind) {
   ASSERT(reader != NULL);
 
   Class& cls = Class::ZoneHandle();
   if (kind == Snapshot::kFull) {
     // Read in the base information.
     ObjectKind kind = reader->Read<ObjectKind>();
 
     // Allocate class object of specified kind.
     cls = Class::GetClass(kind);
     reader->AddBackwardReference(object_id, &cls);
 
+    // Set the object tags.
+    cls.set_tags(tags);
+
     // Set all non object fields.
     cls.set_instance_size(reader->Read<intptr_t>());
     cls.set_type_arguments_instance_field_offset(reader->Read<intptr_t>());
     cls.set_next_field_offset(reader->Read<intptr_t>());
     cls.set_num_native_fields(reader->Read<intptr_t>());
     cls.set_class_state(reader->Read<int8_t>());
     if (reader->Read<bool>()) {
       cls.set_is_const();
     }
     if (reader->Read<bool>()) {
@@ skipping 14 matching lines @@
 }
 
 
 void RawClass::WriteTo(SnapshotWriter* writer,
                        intptr_t object_id,
                        Snapshot::Kind kind) {
   ASSERT(writer != NULL);
   SnapshotWriterVisitor visitor(writer);
 
   // Write out the serialization header value for this object.
-  writer->WriteObjectHeader(kInlined, object_id);
+  writer->WriteSerializationMarker(kInlined, object_id);
 
   if (kind == Snapshot::kFull) {
-    // Write out the class information.
-    writer->WriteObjectHeader(kObjectId, Object::kClassClass);
+    // Write out the class and tags information.
+    writer->WriteObjectHeader(Object::kClassClass, ptr()->tags_);
 
     // Write out all the non object pointer fields.
     // NOTE: cpp_vtable_ is not written.
     writer->Write<ObjectKind>(ptr()->instance_kind_);
     writer->Write<intptr_t>(ptr()->instance_size_);
     writer->Write<intptr_t>(ptr()->type_arguments_instance_field_offset_);
     writer->Write<intptr_t>(ptr()->next_field_offset_);
     writer->Write<intptr_t>(ptr()->num_native_fields_);
     writer->Write<int8_t>(ptr()->class_state_);
     writer->Write<bool>(ptr()->is_const_);
     writer->Write<bool>(ptr()->is_interface_);
 
     // Write out all the object pointer fields.
     visitor.VisitPointers(from(), to());
   } else {
     writer->WriteClassId(this);
   }
 }
 
 
 RawUnresolvedClass* UnresolvedClass::ReadFrom(SnapshotReader* reader,
                                               intptr_t object_id,
+                                              intptr_t tags,
                                               Snapshot::Kind kind) {
   ASSERT(reader != NULL);
 
   // Allocate parameterized type object.
   UnresolvedClass& unresolved_class =
       UnresolvedClass::ZoneHandle(UnresolvedClass::New());
   reader->AddBackwardReference(object_id, &unresolved_class);
 
+  // Set the object tags.
+  unresolved_class.set_tags(tags);
+
   // Set all non object fields.
   unresolved_class.set_token_index(reader->Read<intptr_t>());
 
   // Set all the object fields.
   // TODO(5411462): Need to assert No GC can happen here, even though
   // allocations may happen.
   intptr_t num_flds = (unresolved_class.raw()->to() -
                        unresolved_class.raw()->from());
   for (intptr_t i = 0; i <= num_flds; i++) {
     *(unresolved_class.raw()->from() + i) = reader->ReadObject();
   }
   return unresolved_class.raw();
 }
 
 
 void RawUnresolvedClass::WriteTo(SnapshotWriter* writer,
                                  intptr_t object_id,
                                  Snapshot::Kind kind) {
   ASSERT(writer != NULL);
   SnapshotWriterVisitor visitor(writer);
 
   // Write out the serialization header value for this object.
-  writer->WriteObjectHeader(kInlined, object_id);
+  writer->WriteSerializationMarker(kInlined, object_id);
 
-  // Write out the class information.
-  writer->WriteObjectHeader(kObjectId, Object::kUnresolvedClassClass);
+  // Write out the class and tags information.
+  writer->WriteObjectHeader(Object::kUnresolvedClassClass, ptr()->tags_);
 
   // Write out all the non object pointer fields.
   writer->Write<intptr_t>(ptr()->token_index_);
 
   // Write out all the object pointer fields.
   visitor.VisitPointers(from(), to());
 }
 
 
 RawAbstractType* AbstractType::ReadFrom(SnapshotReader* reader,
-                        intptr_t object_id,
-                        Snapshot::Kind kind) {
+                                        intptr_t object_id,
+                                        intptr_t tags,
+                                        Snapshot::Kind kind) {
   UNREACHABLE();  // AbstractType is an abstract class.
   return NULL;
 }
 
 
 void RawAbstractType::WriteTo(SnapshotWriter* writer,
                               intptr_t object_id,
                               Snapshot::Kind kind) {
   UNREACHABLE();  // AbstractType is an abstract class.
 }
 
 
 RawType* Type::ReadFrom(SnapshotReader* reader,
-                                                  intptr_t object_id,
-                                                  Snapshot::Kind kind) {
+                        intptr_t object_id,
+                        intptr_t tags,
+                        Snapshot::Kind kind) {
   ASSERT(reader != NULL);
 
   // Allocate parameterized type object.
   Type& parameterized_type = Type::ZoneHandle(Type::New());
   reader->AddBackwardReference(object_id, &parameterized_type);
 
+  // Set the object tags.
+  parameterized_type.set_tags(tags);
+
   // Set all non object fields.
   parameterized_type.set_type_state(reader->Read<int8_t>());
 
   // Set all the object fields.
   // TODO(5411462): Need to assert No GC can happen here, even though
   // allocations may happen.
   intptr_t num_flds = (parameterized_type.raw()->to() -
                        parameterized_type.raw()->from());
   for (intptr_t i = 0; i <= num_flds; i++) {
     *(parameterized_type.raw()->from() + i) = reader->ReadObject();
   }
   return parameterized_type.raw();
 }
 
 
 void RawType::WriteTo(SnapshotWriter* writer,
                       intptr_t object_id,
                       Snapshot::Kind kind) {
   ASSERT(writer != NULL);
   SnapshotWriterVisitor visitor(writer);
 
   // Write out the serialization header value for this object.
-  writer->WriteObjectHeader(kInlined, object_id);
+  writer->WriteSerializationMarker(kInlined, object_id);
 
-  // Write out the class information.
-  writer->WriteObjectHeader(kObjectId, Object::kTypeClass);
+  // Write out the class and tags information.
+  writer->WriteObjectHeader(Object::kTypeClass, ptr()->tags_);
 
   // Write out all the non object pointer fields.
   writer->Write<int8_t>(ptr()->type_state_);
 
   // Write out all the object pointer fields.
   visitor.VisitPointers(from(), to());
 }
 
 
 RawTypeParameter* TypeParameter::ReadFrom(SnapshotReader* reader,
                                           intptr_t object_id,
+                                          intptr_t tags,
                                           Snapshot::Kind kind) {
   ASSERT(reader != NULL);
 
   // Allocate type parameter object.
   TypeParameter& type_parameter =
       TypeParameter::ZoneHandle(TypeParameter::New());
   reader->AddBackwardReference(object_id, &type_parameter);
 
+  // Set the object tags.
+  type_parameter.set_tags(tags);
+
   // Set all non object fields.
   type_parameter.set_index(reader->Read<intptr_t>());
   type_parameter.set_type_state(reader->Read<int8_t>());
 
   // Set all the object fields.
   // TODO(5411462): Need to assert No GC can happen here, even though
   // allocations may happen.
   intptr_t num_flds = (type_parameter.raw()->to() -
                        type_parameter.raw()->from());
   for (intptr_t i = 0; i <= num_flds; i++) {
     *(type_parameter.raw()->from() + i) = reader->ReadObject();
   }
 
   return type_parameter.raw();
 }
 
 
 void RawTypeParameter::WriteTo(SnapshotWriter* writer,
                                intptr_t object_id,
                                Snapshot::Kind kind) {
   ASSERT(writer != NULL);
   SnapshotWriterVisitor visitor(writer);
 
   // Write out the serialization header value for this object.
-  writer->WriteObjectHeader(kInlined, object_id);
+  writer->WriteSerializationMarker(kInlined, object_id);
 
-  // Write out the class information.
-  writer->WriteObjectHeader(kObjectId, Object::kTypeParameterClass);
+  // Write out the class and tags information.
+  writer->WriteObjectHeader(Object::kTypeParameterClass, ptr()->tags_);
 
   // Write out all the non object pointer fields.
   writer->Write<intptr_t>(ptr()->index_);
   writer->Write<int8_t>(ptr()->type_state_);
 
   // Write out all the object pointer fields.
   visitor.VisitPointers(from(), to());
 }
 
 
 RawInstantiatedType* InstantiatedType::ReadFrom(SnapshotReader* reader,
                                                 intptr_t object_id,
+                                                intptr_t tags,
                                                 Snapshot::Kind kind) {
   ASSERT(reader != NULL);
   ASSERT(kind == Snapshot::kMessage);
 
   // Allocate instantiated type object.
   InstantiatedType& instantiated_type =
       InstantiatedType::ZoneHandle(InstantiatedType::New());
   reader->AddBackwardReference(object_id, &instantiated_type);
 
+  // Set the object tags.
+  instantiated_type.set_tags(tags);
+
   // Now set all the object fields.
   // TODO(5411462): Need to assert No GC can happen here, even though
   // allocations may happen.
   intptr_t num_flds = (instantiated_type.raw()->to() -
                        instantiated_type.raw()->from());
   for (intptr_t i = 0; i <= num_flds; i++) {
     *(instantiated_type.raw()->from() + i) = reader->ReadObject();
   }
   return instantiated_type.raw();
 }
 
 
 void RawInstantiatedType::WriteTo(SnapshotWriter* writer,
                                   intptr_t object_id,
                                   Snapshot::Kind kind) {
   ASSERT(writer != NULL);
   ASSERT(kind == Snapshot::kMessage);
   SnapshotWriterVisitor visitor(writer);
 
   // Write out the serialization header value for this object.
-  writer->WriteObjectHeader(kInlined, object_id);
+  writer->WriteSerializationMarker(kInlined, object_id);
 
-  // Write out the class information.
-  writer->WriteObjectHeader(kObjectId, Object::kInstantiatedTypeClass);
+  // Write out the class and tags information.
+  writer->WriteObjectHeader(Object::kInstantiatedTypeClass, ptr()->tags_);
 
   // Write out all the object pointer fields.
   visitor.VisitPointers(from(), to());
 }
 
 
 RawAbstractTypeArguments* AbstractTypeArguments::ReadFrom(
     SnapshotReader* reader,
     intptr_t object_id,
+    intptr_t tags,
     Snapshot::Kind kind) {
   UNREACHABLE();  // AbstractTypeArguments is an abstract class.
   return TypeArguments::null();
 }
 
 
 void RawAbstractTypeArguments::WriteTo(SnapshotWriter* writer,
                                        intptr_t object_id,
                                        Snapshot::Kind kind) {
   UNREACHABLE();  // AbstractTypeArguments is an abstract class.
 }
 
 
 RawTypeArguments* TypeArguments::ReadFrom(SnapshotReader* reader,
                                           intptr_t object_id,
+                                          intptr_t tags,
                                           Snapshot::Kind kind) {
   ASSERT(reader != NULL);
 
-  const bool is_canonical = reader->Read<bool>();
   // Read the length so that we can determine instance size to allocate.
   RawSmi* smi_len = GetSmi(reader->Read<intptr_t>());
   intptr_t len = Smi::Value(smi_len);
 
   TypeArguments& type_arguments =
       TypeArguments::Handle(TypeArguments::New(len));
   reader->AddBackwardReference(object_id, &type_arguments);
+
+  // Now set all the object fields.
   AbstractType& type = AbstractType::Handle();
   for (intptr_t i = 0; i < len; i++) {
     type ^= reader->ReadObject();
     type_arguments.SetTypeAt(i, type);
   }
-  type_arguments.set_is_canonical(is_canonical);
+
+  // Set the object tags.
+  type_arguments.set_tags(tags);
 
   return type_arguments.raw();
 }
 
 
 void RawTypeArguments::WriteTo(SnapshotWriter* writer,
                                intptr_t object_id,
                                Snapshot::Kind kind) {
   ASSERT(writer != NULL);
 
   // Write out the serialization header value for this object.
-  writer->WriteObjectHeader(kInlined, object_id);
+  writer->WriteSerializationMarker(kInlined, object_id);
 
-  // Write out the class information.
-  writer->WriteObjectHeader(kObjectId, Object::kTypeArgumentsClass);
+  // Write out the class and tags information.
+  writer->WriteObjectHeader(Object::kTypeArgumentsClass, ptr()->tags_);
 
-  writer->Write<bool>(ptr()->is_canonical_);
   // Write out the length field.
   writer->Write<RawObject*>(ptr()->length_);
 
   // Write out the individual types.
   intptr_t len = Smi::Value(ptr()->length_);
   for (intptr_t i = 0; i < len; i++) {
     writer->WriteObject(ptr()->types_[i]);
   }
 }
 
 
 RawInstantiatedTypeArguments* InstantiatedTypeArguments::ReadFrom(
     SnapshotReader* reader,
     intptr_t object_id,
+    intptr_t tags,
     Snapshot::Kind kind) {
   ASSERT(reader != NULL);
   ASSERT(kind == Snapshot::kMessage);
 
   // Allocate instantiated types object.
   InstantiatedTypeArguments& instantiated_type_arguments =
       InstantiatedTypeArguments::ZoneHandle(InstantiatedTypeArguments::New());
   reader->AddBackwardReference(object_id, &instantiated_type_arguments);
 
+  // Set the object tags.
+  instantiated_type_arguments.set_tags(tags);
+
   // Set all the object fields.
   // TODO(5411462): Need to assert No GC can happen here, even though
   // allocations may happen.
   intptr_t num_flds = (instantiated_type_arguments.raw()->to() -
                        instantiated_type_arguments.raw()->from());
   for (intptr_t i = 0; i <= num_flds; i++) {
     *(instantiated_type_arguments.raw()->from() + i) = reader->ReadObject();
   }
   return instantiated_type_arguments.raw();
 }
 
 
 void RawInstantiatedTypeArguments::WriteTo(SnapshotWriter* writer,
                                            intptr_t object_id,
                                            Snapshot::Kind kind) {
   ASSERT(writer != NULL);
   ASSERT(kind == Snapshot::kMessage);
   SnapshotWriterVisitor visitor(writer);
 
   // Write out the serialization header value for this object.
-  writer->WriteObjectHeader(kInlined, object_id);
+  writer->WriteSerializationMarker(kInlined, object_id);
 
-  // Write out the class information.
-  writer->WriteObjectHeader(kObjectId, Object::kInstantiatedTypeArgumentsClass);
+  // Write out the class and tags information.
+  writer->WriteObjectHeader(Object::kInstantiatedTypeArgumentsClass,
+                            ptr()->tags_);
 
   // Write out all the object pointer fields.
   visitor.VisitPointers(from(), to());
 }
 
 
 RawFunction* Function::ReadFrom(SnapshotReader* reader,
                                 intptr_t object_id,
+                                intptr_t tags,
                                 Snapshot::Kind kind) {
   ASSERT(reader != NULL);
 
   // Allocate function object.
   Function& func = Function::ZoneHandle(Function::New());
   reader->AddBackwardReference(object_id, &func);
 
+  // Set the object tags.
+  func.set_tags(tags);
+
   // Set all the non object fields.
   func.set_token_index(reader->Read<intptr_t>());
   func.set_num_fixed_parameters(reader->Read<intptr_t>());
   func.set_num_optional_parameters(reader->Read<intptr_t>());
   func.set_invocation_counter(reader->Read<intptr_t>());
   func.set_deoptimization_counter(reader->Read<intptr_t>());
   func.set_kind(static_cast<RawFunction::Kind >(reader->Read<intptr_t>()));
   func.set_is_static(reader->Read<bool>());
   func.set_is_const(reader->Read<bool>());
   func.set_is_optimizable(reader->Read<bool>());
@@ skipping 10 matching lines @@
 }
 
 
 void RawFunction::WriteTo(SnapshotWriter* writer,
                           intptr_t object_id,
                           Snapshot::Kind kind) {
   ASSERT(writer != NULL);
   SnapshotWriterVisitor visitor(writer);
 
   // Write out the serialization header value for this object.
-  writer->WriteObjectHeader(kInlined, object_id);
+  writer->WriteSerializationMarker(kInlined, object_id);
 
-  // Write out the class information.
-  writer->WriteObjectHeader(kObjectId, Object::kFunctionClass);
+  // Write out the class and tags information.
+  writer->WriteObjectHeader(Object::kFunctionClass, ptr()->tags_);
 
   // Write out all the non object fields.
   writer->Write<intptr_t>(ptr()->token_index_);
   writer->Write<intptr_t>(ptr()->num_fixed_parameters_);
   writer->Write<intptr_t>(ptr()->num_optional_parameters_);
   writer->Write<intptr_t>(ptr()->invocation_counter_);
   writer->Write<intptr_t>(ptr()->deoptimization_counter_);
   writer->Write<intptr_t>(ptr()->kind_);
   writer->Write<bool>(ptr()->is_static_);
   writer->Write<bool>(ptr()->is_const_);
   writer->Write<bool>(ptr()->is_optimizable_);
 
   // Write out all the object pointer fields.
   visitor.VisitPointers(from(), to());
 }
 
 
 RawField* Field::ReadFrom(SnapshotReader* reader,
                           intptr_t object_id,
+                          intptr_t tags,
                           Snapshot::Kind kind) {
   ASSERT(reader != NULL);
 
   // Allocate field object.
   Field& field = Field::ZoneHandle(Field::New());
   reader->AddBackwardReference(object_id, &field);
 
+  // Set the object tags.
+  field.set_tags(tags);
+
   // Set all non object fields.
   field.set_token_index(reader->Read<intptr_t>());
   field.set_is_static(reader->Read<bool>());
   field.set_is_final(reader->Read<bool>());
   field.set_has_initializer(reader->Read<bool>());
 
   // Set all the object fields.
   // TODO(5411462): Need to assert No GC can happen here, even though
   // allocations may happen.
   intptr_t num_flds = (field.raw()->to() - field.raw()->from());
   for (intptr_t i = 0; i <= num_flds; i++) {
     *(field.raw()->from() + i) = reader->ReadObject();
   }
 
   return field.raw();
 }
 
 
 void RawField::WriteTo(SnapshotWriter* writer,
                        intptr_t object_id,
                        Snapshot::Kind kind) {
   ASSERT(writer != NULL);
   SnapshotWriterVisitor visitor(writer);
 
   // Write out the serialization header value for this object.
-  writer->WriteObjectHeader(kInlined, object_id);
+  writer->WriteSerializationMarker(kInlined, object_id);
 
-  // Write out the class information.
-  writer->WriteObjectHeader(kObjectId, Object::kFieldClass);
+  // Write out the class and tags information.
+  writer->WriteObjectHeader(Object::kFieldClass, ptr()->tags_);
 
   writer->Write<intptr_t>(ptr()->token_index_);
   writer->Write<bool>(ptr()->is_static_);
   writer->Write<bool>(ptr()->is_final_);
   writer->Write<bool>(ptr()->has_initializer_);
 
   // Write out all the object pointer fields.
   visitor.VisitPointers(from(), to());
 }
 
 
 RawTokenStream* TokenStream::ReadFrom(SnapshotReader* reader,
                                       intptr_t object_id,
+                                      intptr_t tags,
                                       Snapshot::Kind kind) {
   ASSERT(reader != NULL);
 
   // Read the length so that we can determine number of tokens to read.
   RawSmi* smi_len = GetSmi(reader->Read<intptr_t>());
   intptr_t len = Smi::Value(smi_len);
 
   // Create the token stream object.
   TokenStream& token_stream = TokenStream::ZoneHandle(TokenStream::New(len));
   reader->AddBackwardReference(object_id, &token_stream);
 
+  // Set the object tags.
+  token_stream.set_tags(tags);
+
   // Read the token stream into the TokenStream.
   String& literal = String::Handle();
   for (intptr_t i = 0; i < len; i++) {
     Token::Kind kind = static_cast<Token::Kind>(
         Smi::Value(GetSmi(reader->Read<intptr_t>())));
     literal ^= reader->ReadObject();
     token_stream.SetTokenAt(i, kind, literal);
   }
   return token_stream.raw();
 }
 
 
 void RawTokenStream::WriteTo(SnapshotWriter* writer,
                              intptr_t object_id,
                              Snapshot::Kind kind) {
   ASSERT(writer != NULL);
 
   // Write out the serialization header value for this object.
-  writer->WriteObjectHeader(kInlined, object_id);
+  writer->WriteSerializationMarker(kInlined, object_id);
 
-  // Write out the class information.
-  writer->WriteObjectHeader(kObjectId, Object::kTokenStreamClass);
+  // Write out the class and tags information.
+  writer->WriteObjectHeader(Object::kTokenStreamClass, ptr()->tags_);
 
   // Write out the length field.
   writer->Write<RawObject*>(ptr()->length_);
 
   // Write out the token stream (token kind and literal).
   intptr_t len = Smi::Value(ptr()->length_);
   for (intptr_t i = 0; i < TokenStream::StreamLength(len); i++) {
     writer->WriteObject(ptr()->data_[i]);
   }
 }
 
 
 RawScript* Script::ReadFrom(SnapshotReader* reader,
                             intptr_t object_id,
+                            intptr_t tags,
                             Snapshot::Kind kind) {
   ASSERT(reader != NULL);
 
   // Allocate script object.
   Script& script = Script::ZoneHandle(Script::New());
   reader->AddBackwardReference(object_id, &script);
 
+  // Set the object tags.
+  script.set_tags(tags);
+
   // Set all the object fields.
   // TODO(5411462): Need to assert No GC can happen here, even though
   // allocations may happen.
   intptr_t num_flds = (script.raw()->to() - script.raw()->from());
   for (intptr_t i = 0; i <= num_flds; i++) {
     *(script.raw()->from() + i) = reader->ReadObject();
   }
 
   return script.raw();
 }
 
 
 void RawScript::WriteTo(SnapshotWriter* writer,
                         intptr_t object_id,
                         Snapshot::Kind kind) {
   ASSERT(writer != NULL);
   ASSERT(tokens_ != TokenStream::null());
   SnapshotWriterVisitor visitor(writer);
 
   // Write out the serialization header value for this object.
-  writer->WriteObjectHeader(kInlined, object_id);
+  writer->WriteSerializationMarker(kInlined, object_id);
 
-  // Write out the class information.
-  writer->WriteObjectHeader(kObjectId, Object::kScriptClass);
+  // Write out the class and tags information.
+  writer->WriteObjectHeader(Object::kScriptClass, ptr()->tags_);
 
   // Write out all the object pointer fields.
   visitor.VisitPointers(from(), to());
 }
 
 
 RawLibrary* Library::ReadFrom(SnapshotReader* reader,
                               intptr_t object_id,
+                              intptr_t tags,
                               Snapshot::Kind kind) {
   ASSERT(reader != NULL);
 
   // Allocate library object.
   Library& library = Library::ZoneHandle(Library::New());
   reader->AddBackwardReference(object_id, &library);
 
+  // Set the object tags.
+  library.set_tags(tags);
+
   // Set all non object fields.
   library.raw_ptr()->num_imports_ = reader->Read<intptr_t>();
   library.raw_ptr()->num_imported_into_ = reader->Read<intptr_t>();
   library.raw_ptr()->num_anonymous_ = reader->Read<intptr_t>();
   library.raw_ptr()->corelib_imported_ = reader->Read<bool>();
   library.raw_ptr()->load_state_ = reader->Read<int8_t>();
   // The native resolver is not serialized.
   Dart_NativeEntryResolver resolver = reader->Read<Dart_NativeEntryResolver>();
   ASSERT(resolver == NULL);
   library.set_native_entry_resolver(resolver);
@@ skipping 10 matching lines @@
 }
 
 
 void RawLibrary::WriteTo(SnapshotWriter* writer,
                          intptr_t object_id,
                          Snapshot::Kind kind) {
   ASSERT(writer != NULL);
   SnapshotWriterVisitor visitor(writer);
 
   // Write out the serialization header value for this object.
-  writer->WriteObjectHeader(kInlined, object_id);
+  writer->WriteSerializationMarker(kInlined, object_id);
 
-  // Write out the class information.
-  writer->WriteObjectHeader(kObjectId, Object::kLibraryClass);
+  // Write out the class and tags information.
+  writer->WriteObjectHeader(Object::kLibraryClass, ptr()->tags_);
 
   writer->Write<intptr_t>(ptr()->num_imports_);
   writer->Write<intptr_t>(ptr()->num_imported_into_);
   writer->Write<intptr_t>(ptr()->num_anonymous_);
   writer->Write<bool>(ptr()->corelib_imported_);
   writer->Write<int8_t>(ptr()->load_state_);
   // We do not serialize the native resolver over, this needs to be explicitly
   // set after deserialization.
   writer->Write<Dart_NativeEntryResolver>(NULL);
 
   // Write out all the object pointer fields.
   visitor.VisitPointers(from(), to());
 }
 
 
 RawLibraryPrefix* LibraryPrefix::ReadFrom(SnapshotReader* reader,
                                           intptr_t object_id,
+                                          intptr_t tags,
                                           Snapshot::Kind kind) {
   ASSERT(reader != NULL);
 
   // Allocate library prefix object.
   LibraryPrefix& prefix = LibraryPrefix::ZoneHandle(LibraryPrefix::New());
   reader->AddBackwardReference(object_id, &prefix);
 
+  // Set the object tags.
+  prefix.set_tags(tags);
+
   // Set all the object fields.
   // TODO(5411462): Need to assert No GC can happen here, even though
   // allocations may happen.
   intptr_t num_flds = (prefix.raw()->to() - prefix.raw()->from());
   for (intptr_t i = 0; i <= num_flds; i++) {
     *(prefix.raw()->from() + i) = reader->ReadObject();
   }
 
   return prefix.raw();
 }
 
 
 void RawLibraryPrefix::WriteTo(SnapshotWriter* writer,
                                intptr_t object_id,
                                Snapshot::Kind kind) {
   ASSERT(writer != NULL);
   SnapshotWriterVisitor visitor(writer);
 
   // Write out the serialization header value for this object.
-  writer->WriteObjectHeader(kInlined, object_id);
+  writer->WriteSerializationMarker(kInlined, object_id);
 
-  // Write out the class information.
-  writer->WriteObjectHeader(kObjectId, Object::kLibraryPrefixClass);
+  // Write out the class and tags information.
+  writer->WriteObjectHeader(Object::kLibraryPrefixClass, ptr()->tags_);
 
   // Write out all the object pointer fields.
   visitor.VisitPointers(from(), to());
 }
 
 
 RawCode* Code::ReadFrom(SnapshotReader* reader,
                         intptr_t object_id,
+                        intptr_t tags,
                         Snapshot::Kind kind) {
   ASSERT(reader != NULL);
 
   // Create Code object.
   Code& code = Code::ZoneHandle(Code::New(0));
   reader->AddBackwardReference(object_id, &code);
   return code.raw();
 }
 
 
 void RawCode::WriteTo(SnapshotWriter* writer,
                       intptr_t object_id,
                       Snapshot::Kind kind) {
   // Currently we do not serialize any code and hence we write
   // out a null object for it.
   ASSERT(writer != NULL);
 
-  writer->WriteObjectHeader(kObjectId, Object::kNullObject);
+  writer->WriteIndexedObject(Object::kNullObject);
 }
 
 
 RawInstructions* Instructions::ReadFrom(SnapshotReader* reader,
                                         intptr_t object_id,
+                                        intptr_t tags,
                                         Snapshot::Kind kind) {
   UNREACHABLE();
   return Instructions::null();
 }
 
 
 void RawInstructions::WriteTo(SnapshotWriter* writer,
                               intptr_t object_id,
                               Snapshot::Kind kind) {
   UNREACHABLE();
 }
 
 
 RawPcDescriptors* PcDescriptors::ReadFrom(SnapshotReader* reader,
                                           intptr_t object_id,
+                                          intptr_t tags,
                                           Snapshot::Kind kind) {
   UNREACHABLE();
   return PcDescriptors::null();
 }
 
 
 void RawPcDescriptors::WriteTo(SnapshotWriter* writer,
                                intptr_t object_id,
                                Snapshot::Kind kind) {
   UNREACHABLE();
 }
 
 
 RawExceptionHandlers* ExceptionHandlers::ReadFrom(SnapshotReader* reader,
                                                   intptr_t object_id,
+                                                  intptr_t tags,
                                                   Snapshot::Kind kind) {
   UNREACHABLE();
   return ExceptionHandlers::null();
 }
 
 
 void RawExceptionHandlers::WriteTo(SnapshotWriter* writer,
                                    intptr_t object_id,
                                    Snapshot::Kind kind) {
   UNREACHABLE();
 }
 
 
 RawContext* Context::ReadFrom(SnapshotReader* reader,
                               intptr_t object_id,
+                              intptr_t tags,
                               Snapshot::Kind kind) {
   ASSERT(reader != NULL);
 
   // Allocate context object.
   intptr_t num_vars = reader->Read<intptr_t>();
   Context& context = Context::ZoneHandle(
       Context::New(num_vars,
                    (kind == Snapshot::kFull) ? Heap::kOld : Heap::kNew));
   reader->AddBackwardReference(object_id, &context);
 
+  // Set the object tags.
+  context.set_tags(tags);
+
   // Set the isolate implicitly.
   context.set_isolate(Isolate::Current());
 
   // Set all the object fields.
   // TODO(5411462): Need to assert No GC can happen here, even though
   // allocations may happen.
   intptr_t num_flds = (context.raw()->to(num_vars) - context.raw()->from());
   for (intptr_t i = 0; i <= num_flds; i++) {
     *(context.raw()->from() + i) = reader->ReadObject();
   }
 
   return context.raw();
 }
 
 
 void RawContext::WriteTo(SnapshotWriter* writer,
                          intptr_t object_id,
                          Snapshot::Kind kind) {
   ASSERT(writer != NULL);
   SnapshotWriterVisitor visitor(writer);
 
   // Write out the serialization header value for this object.
-  writer->WriteObjectHeader(kInlined, object_id);
+  writer->WriteSerializationMarker(kInlined, object_id);
 
-  // Write out the class information.
-  writer->WriteObjectHeader(kObjectId, Object::kContextClass);
+  // Write out the class and tags information.
+  writer->WriteObjectHeader(Object::kContextClass, ptr()->tags_);
 
   // Write out num of variables in the context.
   writer->Write<intptr_t>(ptr()->num_variables_);
 
   // Can't serialize the isolate pointer, we set it implicitly on read.
 
   // Write out all the object pointer fields.
   visitor.VisitPointers(from(), to(ptr()->num_variables_));
 }
 
 
 RawContextScope* ContextScope::ReadFrom(SnapshotReader* reader,
                                         intptr_t object_id,
+                                        intptr_t tags,
                                         Snapshot::Kind kind) {
   ASSERT(reader != NULL);
   ASSERT(kind == Snapshot::kMessage);
 
   // Allocate context scope object.
   intptr_t num_vars = reader->Read<intptr_t>();
   ContextScope& scope = ContextScope::ZoneHandle(ContextScope::New(num_vars));
   reader->AddBackwardReference(object_id, &scope);
 
+  // Set the object tags.
+  scope.set_tags(tags);
+
   // Set all the object fields.
   // TODO(5411462): Need to assert No GC can happen here, even though
   // allocations may happen.
   intptr_t num_flds = (scope.raw()->to(num_vars) - scope.raw()->from());
   for (intptr_t i = 0; i <= num_flds; i++) {
     *(scope.raw()->from() + i) = reader->ReadObject();
   }
 
   return scope.raw();
 }
 
 
 void RawContextScope::WriteTo(SnapshotWriter* writer,
                               intptr_t object_id,
                               Snapshot::Kind kind) {
   ASSERT(writer != NULL);
   ASSERT(kind == Snapshot::kMessage);
   SnapshotWriterVisitor visitor(writer);
 
   // Write out the serialization header value for this object.
-  writer->WriteObjectHeader(kInlined, object_id);
+  writer->WriteSerializationMarker(kInlined, object_id);
 
-  // Write out the class information.
-  writer->WriteObjectHeader(kObjectId, Object::kContextScopeClass);
+  // Write out the class and tags information.
+  writer->WriteObjectHeader(Object::kContextScopeClass, ptr()->tags_);
 
   // Serialize number of variables.
   writer->Write<intptr_t>(ptr()->num_variables_);
 
   // Write out all the object pointer fields.
   visitor.VisitPointers(from(), to(ptr()->num_variables_));
 }
 
 
 RawUnhandledException* UnhandledException::ReadFrom(SnapshotReader* reader,
                                                     intptr_t object_id,
+                                                    intptr_t tags,
                                                     Snapshot::Kind kind) {
   UNIMPLEMENTED();
   return UnhandledException::null();
 }
 
 
 void RawUnhandledException::WriteTo(SnapshotWriter* writer,
                                     intptr_t object_id,
                                     Snapshot::Kind kind) {
   UNIMPLEMENTED();
 }
 
 
 RawApiError* ApiError::ReadFrom(SnapshotReader* reader,
-                                    intptr_t object_id,
-                                    Snapshot::Kind kind) {
+                                intptr_t object_id,
+                                intptr_t tags,
+                                Snapshot::Kind kind) {
   UNIMPLEMENTED();
   return ApiError::null();
 }
 
 
 void RawApiError::WriteTo(SnapshotWriter* writer,
                           intptr_t object_id,
                           Snapshot::Kind kind) {
   UNIMPLEMENTED();
 }
 
 
 RawInstance* Instance::ReadFrom(SnapshotReader* reader,
                                 intptr_t object_id,
+                                intptr_t tags,
                                 Snapshot::Kind kind) {
   UNREACHABLE();
   return Instance::null();
 }
 
 
 void RawInstance::WriteTo(SnapshotWriter* writer,
                           intptr_t object_id,
                           Snapshot::Kind kind) {
   UNREACHABLE();
 }
 
 
 RawMint* Mint::ReadFrom(SnapshotReader* reader,
                         intptr_t object_id,
+                        intptr_t tags,
                         Snapshot::Kind kind) {
   ASSERT(reader != NULL);
 
   // Read the 64 bit value for the object.
   int64_t value = reader->Read<int64_t>();
 
   // Create a Mint object.
   Mint& mint = Mint::ZoneHandle(
       Mint::New(value, (kind == Snapshot::kFull) ? Heap::kOld : Heap::kNew));
   reader->AddBackwardReference(object_id, &mint);
+
+  // Set the object tags.
+  mint.set_tags(tags);
+
   return mint.raw();
 }
 
 
 void RawMint::WriteTo(SnapshotWriter* writer,
                       intptr_t object_id,
                       Snapshot::Kind kind) {
   ASSERT(writer != NULL);
 
   // Write out the serialization header value for this object.
-  writer->WriteObjectHeader(kInlined, object_id);
+  writer->WriteSerializationMarker(kInlined, object_id);
 
-  // Write out the class information.
-  writer->WriteObjectHeader(kObjectId, ObjectStore::kMintClass);
+  // Write out the class and tags information.
+  writer->WriteObjectHeader(ObjectStore::kMintClass, ptr()->tags_);
 
   // Write out the 64 bit value.
   writer->Write<int64_t>(ptr()->value_);
 }
 
 
 RawBigint* Bigint::ReadFrom(SnapshotReader* reader,
                             intptr_t object_id,
+                            intptr_t tags,
                             Snapshot::Kind kind) {
   ASSERT(reader != NULL);
   // Read in the HexCString representation of the bigint.
   intptr_t len = reader->Read<intptr_t>();
   char* str = reinterpret_cast<char*>(ZoneAllocator(len + 1));
   str[len] = '\0';
   for (intptr_t i = 0; i < len; i++) {
     str[i] = reader->Read<uint8_t>();
   }
   // Create a Bigint object from HexCString.
   Bigint& obj = Bigint::ZoneHandle(BigintOperations::FromHexCString(str));
   reader->AddBackwardReference(object_id, &obj);
+
+  // Set the object tags.
+  obj.set_tags(tags);
+
   return obj.raw();
 }
 
 
 void RawBigint::WriteTo(SnapshotWriter* writer,
                         intptr_t object_id,
                         Snapshot::Kind kind) {
   ASSERT(writer != NULL);
 
   // Write out the serialization header value for this object.
-  writer->WriteObjectHeader(kInlined, object_id);
+  writer->WriteSerializationMarker(kInlined, object_id);
 
-  // Write out the class information.
-  writer->WriteObjectHeader(kObjectId, ObjectStore::kBigintClass);
+  // Write out the class and tags information.
+  writer->WriteObjectHeader(ObjectStore::kBigintClass, ptr()->tags_);
 
   // Write out the bigint value as a HEXCstring.
   ptr()->bn_.d = ptr()->data_;
   const char* str = BigintOperations::ToHexCString(&ptr()->bn_, &ZoneAllocator);
   intptr_t len = strlen(str);
   writer->Write<intptr_t>(len-2);
   for (intptr_t i = 2; i < len; i++) {
     writer->Write<uint8_t>(str[i]);
   }
 }
 
 
 RawDouble* Double::ReadFrom(SnapshotReader* reader,
                             intptr_t object_id,
+                            intptr_t tags,
                             Snapshot::Kind kind) {
   ASSERT(reader != NULL);
   // Read the double value for the object.
   double value = reader->Read<double>();
   // Create a double object.
   Double& dbl = Double::ZoneHandle(
       Double::New(value, (kind == Snapshot::kFull) ? Heap::kOld : Heap::kNew));
   reader->AddBackwardReference(object_id, &dbl);
+
+  // Set the object tags.
+  dbl.set_tags(tags);
+
   return dbl.raw();
 }
 
 
 void RawDouble::WriteTo(SnapshotWriter* writer,
                         intptr_t object_id,
                         Snapshot::Kind kind) {
   ASSERT(writer != NULL);
 
   // Write out the serialization header value for this object.
-  writer->WriteObjectHeader(kInlined, object_id);
+  writer->WriteSerializationMarker(kInlined, object_id);
 
-  // Write out the class information.
-  writer->WriteObjectHeader(kObjectId, ObjectStore::kDoubleClass);
+  // Write out the class and tags information.
+  writer->WriteObjectHeader(ObjectStore::kDoubleClass, ptr()->tags_);
 
   // Write out the double value.
   writer->Write<double>(ptr()->value_);
 }
 
 
 RawString* String::ReadFrom(SnapshotReader* reader,
                             intptr_t object_id,
+                            intptr_t tags,
                             Snapshot::Kind kind) {
   UNREACHABLE();  // String is an abstract class.
   return String::null();
 }
 
 
 void RawString::WriteTo(SnapshotWriter* writer,
                         intptr_t object_id,
                         Snapshot::Kind kind) {
   UNREACHABLE();  // String is an abstract class.
 }
 
 
 template<typename HandleType, typename CharacterType>
 RawString* String::ReadFromImpl(SnapshotReader* reader,
                                 intptr_t object_id,
+                                intptr_t tags,
                                 Snapshot::Kind kind) {
   ASSERT(reader != NULL);
   // Read the length so that we can determine instance size to allocate.
   RawSmi* smi_len = GetSmi(reader->Read<intptr_t>());
   intptr_t len = Smi::Value(smi_len);
   RawSmi* smi_hash = GetSmi(reader->Read<intptr_t>());
 
   // Set up the string object.
   HandleType& str_obj = HandleType::ZoneHandle(HandleType::New(
       len, (kind == Snapshot::kFull) ? Heap::kOld : Heap::kNew));
   for (intptr_t i = 0; i < len; i++) {
     *str_obj.CharAddr(i) = reader->Read<CharacterType>();
   }
   reader->AddBackwardReference(object_id, &str_obj);
+
+  // Set the object tags.
+  str_obj.set_tags(tags);
+
+  // Set up the hash value.
   str_obj.SetHash(Smi::Value(smi_hash));
+
   return str_obj.raw();
 }
 
 
 RawOneByteString* OneByteString::ReadFrom(SnapshotReader* reader,
                                           intptr_t object_id,
+                                          intptr_t tags,
                                           Snapshot::Kind kind) {
   return static_cast<RawOneByteString*>(
-      ReadFromImpl<OneByteString, uint8_t>(reader, object_id, kind));
+      ReadFromImpl<OneByteString, uint8_t>(reader, object_id, tags, kind));
 }
 
 
 RawTwoByteString* TwoByteString::ReadFrom(SnapshotReader* reader,
                                           intptr_t object_id,
+                                          intptr_t tags,
                                           Snapshot::Kind kind) {
   return static_cast<RawTwoByteString*>(
-      ReadFromImpl<TwoByteString, uint16_t>(reader, object_id, kind));
+      ReadFromImpl<TwoByteString, uint16_t>(reader, object_id, tags, kind));
 }
 
 
 RawFourByteString* FourByteString::ReadFrom(SnapshotReader* reader,
                                             intptr_t object_id,
+                                            intptr_t tags,
                                             Snapshot::Kind kind) {
   return static_cast<RawFourByteString*>(
-      ReadFromImpl<FourByteString, uint32_t>(reader, object_id, kind));
+      ReadFromImpl<FourByteString, uint32_t>(reader, object_id, tags, kind));
 }
 
 
 template<typename T>
 static void StringWriteTo(SnapshotWriter* writer,
                           intptr_t object_id,
+                          Snapshot::Kind kind,
                           intptr_t class_id,
-                          Snapshot::Kind kind,
+                          intptr_t tags,
                           RawSmi* length,
                           RawSmi* hash,
                           T* data) {
   ASSERT(writer != NULL);
   intptr_t len = Smi::Value(length);
 
   // Write out the serialization header value for this object.
-  writer->WriteObjectHeader(kInlined, object_id);
+  writer->WriteSerializationMarker(kInlined, object_id);
 
-  // Write out the class information.
-  writer->WriteObjectHeader(kObjectId, class_id);
+  // Write out the class and tags information.
+  writer->WriteObjectHeader(class_id, tags);
 
   // Write out the length field.
   writer->Write<RawObject*>(length);
 
   // Write out the hash field.
   writer->Write<RawObject*>(hash);
 
   // Write out the string.
   for (intptr_t i = 0; i < len; i++) {
     writer->Write(data[i]);
   }
 }
 
 
 void RawOneByteString::WriteTo(SnapshotWriter* writer,
                                intptr_t object_id,
                                Snapshot::Kind kind) {
   StringWriteTo(writer,
                 object_id,
+                kind,
                 ObjectStore::kOneByteStringClass,
-                kind,
+                ptr()->tags_,
                 ptr()->length_,
                 ptr()->hash_,
                 ptr()->data_);
 }
 
 
 void RawTwoByteString::WriteTo(SnapshotWriter* writer,
                                intptr_t object_id,
                                Snapshot::Kind kind) {
   StringWriteTo(writer,
                 object_id,
+                kind,
                 ObjectStore::kTwoByteStringClass,
-                kind,
+                ptr()->tags_,
                 ptr()->length_,
                 ptr()->hash_,
                 ptr()->data_);
 }
 
 
 void RawFourByteString::WriteTo(SnapshotWriter* writer,
                                 intptr_t object_id,
                                 Snapshot::Kind kind) {
   StringWriteTo(writer,
                 object_id,
+                kind,
                 ObjectStore::kFourByteStringClass,
-                kind,
+                ptr()->tags_,
                 ptr()->length_,
                 ptr()->hash_,
                 ptr()->data_);
 }
 
 
 RawExternalOneByteString* ExternalOneByteString::ReadFrom(
     SnapshotReader* reader,
     intptr_t object_id,
+    intptr_t tags,
     Snapshot::Kind kind) {
   UNREACHABLE();
   return ExternalOneByteString::null();
 }
 
 
 RawExternalTwoByteString* ExternalTwoByteString::ReadFrom(
     SnapshotReader* reader,
     intptr_t object_id,
+    intptr_t tags,
     Snapshot::Kind kind) {
   UNREACHABLE();
   return ExternalTwoByteString::null();
 }
 
 
 RawExternalFourByteString* ExternalFourByteString::ReadFrom(
     SnapshotReader* reader,
     intptr_t object_id,
+    intptr_t tags,
     Snapshot::Kind kind) {
   UNREACHABLE();
   return ExternalFourByteString::null();
 }
 
 
 void RawExternalOneByteString::WriteTo(SnapshotWriter* writer,
                                        intptr_t object_id,
                                        Snapshot::Kind kind) {
   // Serialize as a non-external one byte string.
   StringWriteTo(writer,
                 object_id,
+                kind,
                 ObjectStore::kOneByteStringClass,
-                kind,
+                ptr()->tags_,
                 ptr()->length_,
                 ptr()->hash_,
                 ptr()->external_data_->data_);
 }
 
 
 void RawExternalTwoByteString::WriteTo(SnapshotWriter* writer,
                                        intptr_t object_id,
                                        Snapshot::Kind kind) {
   // Serialize as a non-external two byte string.
   StringWriteTo(writer,
                 object_id,
+                kind,
                 ObjectStore::kTwoByteStringClass,
-                kind,
+                ptr()->tags_,
                 ptr()->length_,
                 ptr()->hash_,
                 ptr()->external_data_->data_);
 }
 
 
 void RawExternalFourByteString::WriteTo(SnapshotWriter* writer,
                                         intptr_t object_id,
                                         Snapshot::Kind kind) {
   // Serialize as a non-external four byte string.
   StringWriteTo(writer,
                 object_id,
+                kind,
                 ObjectStore::kFourByteStringClass,
-                kind,
+                ptr()->tags_,
                 ptr()->length_,
                 ptr()->hash_,
                 ptr()->external_data_->data_);
 }
 
 
 RawBool* Bool::ReadFrom(SnapshotReader* reader,
-                          intptr_t object_id,
-                          Snapshot::Kind kind) {
+                        intptr_t object_id,
+                        intptr_t tags,
+                        Snapshot::Kind kind) {
   UNREACHABLE();
   return Bool::null();
 }
 
 
 void RawBool::WriteTo(SnapshotWriter* writer,
                       intptr_t object_id,
                       Snapshot::Kind kind) {
   UNREACHABLE();
 }
 
 
 template <class T>
 static RawObject* ArrayReadFrom(SnapshotReader* reader,
                                 intptr_t object_id,
+                                intptr_t tags,
                                 Snapshot::Kind kind) {
   ASSERT(reader != NULL);
 
   // Read the length so that we can determine instance size to allocate.
   RawSmi* smi_len = GetSmi(reader->Read<intptr_t>());
   intptr_t len = Smi::Value(smi_len);
   T& result = T::Handle(
       T::New(len, (kind == Snapshot::kFull) ? Heap::kOld : Heap::kNew));
   reader->AddBackwardReference(object_id, &result);
 
+  // Set the object tags.
+  result.set_tags(tags);
+
+  // Setup the object fields.
   AbstractTypeArguments& type_arguments = AbstractTypeArguments::Handle();
   type_arguments ^= reader->ReadObject();
   result.SetTypeArguments(type_arguments);
 
   Object& obj = Object::Handle();
   for (intptr_t i = 0; i < len; i++) {
     obj = reader->ReadObject();
     result.SetAt(i, obj);
   }
   return result.raw();
 }
 
 
 RawArray* Array::ReadFrom(SnapshotReader* reader,
                           intptr_t object_id,
+                          intptr_t tags,
                           Snapshot::Kind kind) {
-  return reinterpret_cast<RawArray*>(ArrayReadFrom<Array>(reader,
-                                                          object_id,
-                                                          kind));
+  return reinterpret_cast<RawArray*>(
+      ArrayReadFrom<Array>(reader, object_id, tags, kind));
 }
 
 
 RawImmutableArray* ImmutableArray::ReadFrom(SnapshotReader* reader,
                                             intptr_t object_id,
+                                            intptr_t tags,
                                             Snapshot::Kind kind) {
   return reinterpret_cast<RawImmutableArray*>(
-      ArrayReadFrom<ImmutableArray>(reader, object_id, kind));
+      ArrayReadFrom<ImmutableArray>(reader, object_id, tags, kind));
 }
 
 
 static void ArrayWriteTo(SnapshotWriter* writer,
                          intptr_t object_id,
                          Snapshot::Kind kind,
                          intptr_t array_kind,
+                         intptr_t tags,
                          RawSmi* length,
                          RawAbstractTypeArguments* type_arguments,
                          RawObject* data[]) {
   ASSERT(writer != NULL);
   intptr_t len = Smi::Value(length);
 
   // Write out the serialization header value for this object.
-  writer->WriteObjectHeader(kInlined, object_id);
+  writer->WriteSerializationMarker(kInlined, object_id);
 
-  // Write out the class information.
-  writer->WriteObjectHeader(kObjectId, array_kind);
+  // Write out the class and tags information.
+  writer->WriteObjectHeader(array_kind, tags);
 
   // Write out the length field.
   writer->Write<RawObject*>(length);
 
   // Write out the type arguments.
   writer->WriteObject(type_arguments);
 
   // Write out the individual objects.
   for (intptr_t i = 0; i < len; i++) {
     writer->WriteObject(data[i]);
   }
 }
 
 
 void RawArray::WriteTo(SnapshotWriter* writer,
                        intptr_t object_id,
                        Snapshot::Kind kind) {
   ArrayWriteTo(writer,
                object_id,
                kind,
                ObjectStore::kArrayClass,
+               ptr()->tags_,
                ptr()->length_,
                ptr()->type_arguments_,
                ptr()->data());
 }
 
 
 void RawImmutableArray::WriteTo(SnapshotWriter* writer,
                                 intptr_t object_id,
                                 Snapshot::Kind kind) {
   ArrayWriteTo(writer,
                object_id,
                kind,
                ObjectStore::kImmutableArrayClass,
+               ptr()->tags_,
                ptr()->length_,
                ptr()->type_arguments_,
                ptr()->data());
 }
 
 
 RawByteBuffer* ByteBuffer::ReadFrom(SnapshotReader* reader,
                                     intptr_t object_id,
+                                    intptr_t tags,
                                     Snapshot::Kind kind) {
   UNIMPLEMENTED();
   return ByteBuffer::null();
 }
 
 
 void RawByteBuffer::WriteTo(SnapshotWriter* writer,
                             intptr_t object_id,
                             Snapshot::Kind kind) {
   UNIMPLEMENTED();
 }
 
 
 RawClosure* Closure::ReadFrom(SnapshotReader* reader,
                               intptr_t object_id,
+                              intptr_t tags,
                               Snapshot::Kind kind) {
   UNIMPLEMENTED();
   return Closure::null();
 }
 
 
 void RawClosure::WriteTo(SnapshotWriter* writer,
                          intptr_t object_id,
                          Snapshot::Kind kind) {
   UNIMPLEMENTED();
 }
 
 
 RawStacktrace* Stacktrace::ReadFrom(SnapshotReader* reader,
                                     intptr_t object_id,
+                                    intptr_t tags,
                                     Snapshot::Kind kind) {
   UNIMPLEMENTED();
   return Stacktrace::null();
 }
 
 
 void RawStacktrace::WriteTo(SnapshotWriter* writer,
                             intptr_t object_id,
                             Snapshot::Kind kind) {
   UNIMPLEMENTED();
 }
 
 
 RawJSRegExp* JSRegExp::ReadFrom(SnapshotReader* reader,
                                 intptr_t object_id,
+                                intptr_t tags,
                                 Snapshot::Kind kind) {
   ASSERT(reader != NULL);
   ASSERT(kind == Snapshot::kMessage);
 
   // Read the length so that we can determine instance size to allocate.
   RawSmi* smi_len = GetSmi(reader->Read<intptr_t>());
   intptr_t len = Smi::Value(smi_len);
 
   // Allocate JSRegExp object.
   JSRegExp& regex = JSRegExp::ZoneHandle(
       JSRegExp::New(len, (kind == Snapshot::kFull) ? Heap::kOld : Heap::kNew));
   reader->AddBackwardReference(object_id, &regex);
 
+  // Set the object tags.
+  regex.set_tags(tags);
+
   // Read and Set all the other fields.
   regex.raw_ptr()->num_bracket_expressions_ = GetSmi(reader->Read<intptr_t>());
   String& pattern = String::Handle();
   pattern ^= reader->ReadObject();
   regex.raw_ptr()->pattern_ = pattern.raw();
   regex.raw_ptr()->type_ = reader->Read<intptr_t>();
   regex.raw_ptr()->flags_ = reader->Read<intptr_t>();
 
   // TODO(5411462): Need to implement a way of recompiling the regex.
 
   return regex.raw();
 }
 
 
 void RawJSRegExp::WriteTo(SnapshotWriter* writer,
                             intptr_t object_id,
                             Snapshot::Kind kind) {
   ASSERT(writer != NULL);
   ASSERT(kind == Snapshot::kMessage);
 
   // Write out the serialization header value for this object.
-  writer->WriteObjectHeader(kInlined, object_id);
+  writer->WriteSerializationMarker(kInlined, object_id);
 
-  // Write out the class information.
-  writer->WriteObjectHeader(kObjectId, ObjectStore::kJSRegExpClass);
+  // Write out the class and tags information.
+  writer->WriteObjectHeader(ObjectStore::kJSRegExpClass, ptr()->tags_);
 
   // Write out the data length field.
   writer->Write<RawObject*>(ptr()->data_length_);
 
   // Write out all the other fields.
   writer->Write<RawObject*>(ptr()->num_bracket_expressions_);
   writer->WriteObject(ptr()->pattern_);
   writer->Write<intptr_t>(ptr()->type_);
   writer->Write<intptr_t>(ptr()->flags_);
 
   // Do not write out the data part which is native.
 }
 
 }  // namespace dart