Toward precompiled snapshots.

runtime/vm/raw_object_snapshot.cc

 // Copyright (c) 2012, 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/object.h"
 #include "vm/object_store.h"
 #include "vm/snapshot.h"
 #include "vm/stub_code.h"
 #include "vm/symbols.h"
 #include "vm/visitor.h"
@@ skipping 689 matching lines @@
     (*reader->PassiveObjectHandle()) =
         reader->ReadObjectImpl(kAsReference, object_id, (i + from_offset));
     func.StorePointer((func.raw()->from() + i),
                       reader->PassiveObjectHandle()->raw());
   }
 
   if (!reader->snapshot_code()) {
     // Initialize all fields that are not part of the snapshot.
     func.ClearICDataArray();
     func.ClearCode();
+  } else {
+    // TODO(rmacnak): Fix entry_point_.
   }
   return func.raw();
 }
 
 
 void RawFunction::WriteTo(SnapshotWriter* writer,
                           intptr_t object_id,
                           Snapshot::Kind kind) {
   ASSERT(writer != NULL);
   ASSERT((kind == Snapshot::kScript) || (kind == Snapshot::kFull));
@@ skipping 461 matching lines @@
   // Write out all the object pointer fields.
   SnapshotWriterVisitor visitor(writer);
   visitor.VisitPointers(from(), to());
 }
 
 
 RawCode* Code::ReadFrom(SnapshotReader* reader,
                         intptr_t object_id,
                         intptr_t tags,
                         Snapshot::Kind kind) {
-  UNREACHABLE();  // Untested.
   ASSERT(reader->snapshot_code());
   ASSERT(kind == Snapshot::kFull);
 
   Code& result = Code::ZoneHandle(reader->zone(), NEW_OBJECT_WITH_LEN(Code, 0));
   reader->AddBackRef(object_id, &result, kIsDeserialized);
 
   result.set_compile_timestamp(reader->Read<int64_t>());
   result.set_state_bits(reader->Read<int32_t>());
   result.set_entry_patch_pc_offset(reader->Read<int32_t>());
   result.set_patch_code_pc_offset(reader->Read<int32_t>());
   result.set_lazy_deopt_pc_offset(reader->Read<int32_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 = (result.raw()->to() - result.raw()->from());
   for (intptr_t i = 0; i <= num_flds; i++) {
     (*reader->PassiveObjectHandle()) = reader->ReadObjectImpl(kAsReference);
     result.StorePointer((result.raw()->from() + i),
                         reader->PassiveObjectHandle()->raw());
   }
 
+  // TODO(rmacnak): Fix entry_point_.
+
   return result.raw();
 }
 
 
 void RawCode::WriteTo(SnapshotWriter* writer,
                       intptr_t object_id,
                       Snapshot::Kind kind) {
   ASSERT(writer->snapshot_code());
   ASSERT(kind == Snapshot::kFull);
 
@@ skipping 21 matching lines @@
   // Write out all the object pointer fields.
   SnapshotWriterVisitor visitor(writer);
   visitor.VisitPointers(from(), to());
 }
 
 
 RawInstructions* Instructions::ReadFrom(SnapshotReader* reader,
                                         intptr_t object_id,
                                         intptr_t tags,
                                         Snapshot::Kind kind) {
-  UNREACHABLE();  // Untested.
   ASSERT(reader->snapshot_code());
   ASSERT(kind == Snapshot::kFull);
 
-  intptr_t id = reader->Read<int32_t>();
+  intptr_t full_tags = static_cast<uword>(reader->Read<intptr_t>());
+  intptr_t offset = reader->Read<int32_t>();
   Instructions& result =
       Instructions::ZoneHandle(reader->zone(),
-                               reader->GetInstructionsById(id));
+                               reader->GetInstructionsAt(offset, full_tags));
   reader->AddBackRef(object_id, &result, kIsDeserialized);
+
+  {
+    // TODO(rmacnak): Drop after calling convention change.
+    Code::CheckedHandle(reader->ReadObjectImpl(kAsReference));
+    ObjectPool::CheckedHandle(reader->ReadObjectImpl(kAsReference));
+  }
+
   return result.raw();
 }
 
 
 void RawInstructions::WriteTo(SnapshotWriter* writer,
                               intptr_t object_id,
                               Snapshot::Kind kind) {
   ASSERT(writer->snapshot_code());
   ASSERT(kind == Snapshot::kFull);
 
   {
     // TODO(rmacnak): Drop after calling convention change.
     writer->WriteInlinedObjectHeader(object_id);
     writer->WriteVMIsolateObject(kInstructionsCid);
     writer->WriteTags(writer->GetObjectTags(this));
+  }
+
+  writer->Write<intptr_t>(writer->GetObjectTags(this));  // For sanity check.
+
+  // Temporarily restore the object header for writing to the text section.
+  // TODO(asiva): Don't mutate object headers during serialization.
+  uword object_tags = writer->GetObjectTags(this);
+  uword snapshot_tags = ptr()->tags_;
+  ptr()->tags_ = object_tags;
+  writer->Write<int32_t>(writer->GetInstructionsId(this));
+  ptr()->tags_ = snapshot_tags;
+
+  {
+    // TODO(rmacnak): Drop after calling convention change.
     writer->WriteObjectImpl(ptr()->code_, kAsReference);
     writer->WriteObjectImpl(ptr()->object_pool_, kAsReference);
   }
-
-  writer->Write<int32_t>(writer->GetInstructionsId(this));
 }
 
 
 RawObjectPool* ObjectPool::ReadFrom(SnapshotReader* reader,
                                     intptr_t object_id,
                                     intptr_t tags,
                                     Snapshot::Kind kind) {
-  UNREACHABLE();  // Untested.
   ASSERT(reader->snapshot_code());
   ASSERT(kind == Snapshot::kFull);
 
   intptr_t length = reader->Read<intptr_t>();
 
   ObjectPool& result =
       ObjectPool::ZoneHandle(reader->zone(),
                              NEW_OBJECT_WITH_LEN(ObjectPool, length));
   reader->AddBackRef(object_id, &result, kIsDeserialized);
 
-  RawTypedData* info_array = result.raw_ptr()->info_array_->ptr();
+  const TypedData& info_array =
+      TypedData::Handle(reader->NewTypedData(kTypedDataInt8ArrayCid, length));
+  result.set_info_array(info_array);
 
-  // Set all the object fields.
-  // TODO(5411462): Need to assert No GC can happen here, even though
-  // allocations may happen.
+  NoSafepointScope no_safepoint;
   for (intptr_t i = 0; i < length; i++) {
     ObjectPool::EntryType entry_type =
-        static_cast<ObjectPool::EntryType>(reader->Read<uint8_t>());
-    info_array->data()[i] = entry_type;
+        static_cast<ObjectPool::EntryType>(reader->Read<int8_t>());
+    *reinterpret_cast<int8_t*>(info_array.DataAddr(i)) = entry_type;
     switch (entry_type) {
       case ObjectPool::kTaggedObject: {
         (*reader->PassiveObjectHandle()) = reader->ReadObjectImpl(kAsReference);
         result.SetObjectAt(i, *(reader->PassiveObjectHandle()));
         break;
       }
       case ObjectPool::kImmediate: {
         intptr_t raw_value = reader->Read<intptr_t>();
         result.SetRawValueAt(i, raw_value);
         break;
@@ skipping 27 matching lines @@
   writer->WriteTags(writer->GetObjectTags(this));
 
   intptr_t length = ptr()->length_;
   RawTypedData* info_array = ptr()->info_array_->ptr();
   ASSERT(info_array != TypedData::null());
 
   writer->Write<intptr_t>(length);
   for (intptr_t i = 0; i < length; i++) {
     ObjectPool::EntryType entry_type =
         static_cast<ObjectPool::EntryType>(info_array->data()[i]);
-    writer->Write<uint8_t>(entry_type);
+    writer->Write<int8_t>(entry_type);
     Entry& entry = ptr()->data()[i];
     switch (entry_type) {
       case ObjectPool::kTaggedObject:
         writer->WriteObjectImpl(entry.raw_obj_, kAsReference);
         break;
       case ObjectPool::kImmediate:
         writer->Write<intptr_t>(entry.raw_value_);
         break;
       case ObjectPool::kExternalLabel:
         // TODO(rmacnak): Write symbolically.
         writer->Write<intptr_t>(entry.raw_value_);
         break;
       default:
         UNREACHABLE();
     }
   }
 }
 
 
 RawPcDescriptors* PcDescriptors::ReadFrom(SnapshotReader* reader,
                                           intptr_t object_id,
                                           intptr_t tags,
                                           Snapshot::Kind kind) {
-  UNREACHABLE();  // Untested.
   ASSERT(reader->snapshot_code());
+  ASSERT(kind == Snapshot::kFull);
 
   const int32_t length = reader->Read<int32_t>();
-  PcDescriptors& result = PcDescriptors::ZoneHandle(reader->zone(),
-                                                    PcDescriptors::New(length));
+  PcDescriptors& result =
+      PcDescriptors::ZoneHandle(reader->zone(),
+                                NEW_OBJECT_WITH_LEN(PcDescriptors, length));
   reader->AddBackRef(object_id, &result, kIsDeserialized);
 
   if (result.Length() > 0) {
     NoSafepointScope no_safepoint;
     intptr_t len = result.Length();
     uint8_t* data = result.UnsafeMutableNonPointer(result.raw_ptr()->data());
     reader->ReadBytes(data, len);
   }
 
   return result.raw();
 }
 
 
 void RawPcDescriptors::WriteTo(SnapshotWriter* writer,
                                intptr_t object_id,
                                Snapshot::Kind kind) {
   ASSERT(writer->snapshot_code());
+  ASSERT(kind == Snapshot::kFull);
 
   // Write out the serialization header value for this object.
   writer->WriteInlinedObjectHeader(object_id);
   writer->WriteIndexedObject(kPcDescriptorsCid);
   writer->WriteTags(writer->GetObjectTags(this));
   writer->Write<int32_t>(ptr()->length_);
   if (ptr()->length_ > 0) {
     intptr_t len = ptr()->length_;
     uint8_t* data = reinterpret_cast<uint8_t*>(ptr()->data());
     writer->WriteBytes(data, len);
   }
 }
 
 
 RawStackmap* Stackmap::ReadFrom(SnapshotReader* reader,
                                 intptr_t object_id,
                                 intptr_t tags,
                                 Snapshot::Kind kind) {
-  UNREACHABLE();  // Untested.
   ASSERT(reader->snapshot_code());
+  ASSERT(kind == Snapshot::kFull);
 
   const int32_t length = reader->Read<int32_t>();
-  const int32_t register_bit_count = reader->Read<int32_t>();
-  const uword pc_offset = reader->Read<uint32_t>();
-
   Stackmap& result =
       Stackmap::ZoneHandle(reader->zone(),
-        Stackmap::New(length, register_bit_count, pc_offset));
+                           reader->NewStackmap(length));
   reader->AddBackRef(object_id, &result, kIsDeserialized);
 
-  if (result.Length() > 0) {
+  result.SetRegisterBitCount(reader->Read<int32_t>());
+  result.SetPcOffset(reader->Read<uint32_t>());
+
+  if (length > 0) {
     NoSafepointScope no_safepoint;
     intptr_t len = (result.Length() + 7) / 8;
     uint8_t* data = result.UnsafeMutableNonPointer(result.raw_ptr()->data());
     reader->ReadBytes(data, len);
   }
 
   return result.raw();
 }
 
 
 void RawStackmap::WriteTo(SnapshotWriter* writer,
                           intptr_t object_id,
                           Snapshot::Kind kind) {
   ASSERT(writer->snapshot_code());
+  ASSERT(kind == Snapshot::kFull);
 
   // Write out the serialization header value for this object.
   writer->WriteInlinedObjectHeader(object_id);
   writer->WriteIndexedObject(kStackmapCid);
   writer->WriteTags(writer->GetObjectTags(this));
+
   writer->Write<int32_t>(ptr()->length_);
   writer->Write<int32_t>(ptr()->register_bit_count_);
   writer->Write<uint32_t>(ptr()->pc_offset_);
   if (ptr()->length_ > 0) {
     intptr_t len = (ptr()->length_ + 7) / 8;
     uint8_t* data = reinterpret_cast<uint8_t*>(ptr()->data());
     writer->WriteBytes(data, len);
   }
 }
 
 
 RawLocalVarDescriptors* LocalVarDescriptors::ReadFrom(SnapshotReader* reader,
                                                       intptr_t object_id,
                                                       intptr_t tags,
                                                       Snapshot::Kind kind) {
-  UNREACHABLE();  // Untested.
   ASSERT(reader->snapshot_code());
+  ASSERT(kind == Snapshot::kFull);
 
   const int32_t num_entries = reader->Read<int32_t>();
 
   LocalVarDescriptors& result =
       LocalVarDescriptors::ZoneHandle(reader->zone(),
-        LocalVarDescriptors::New(num_entries));
+                                      NEW_OBJECT_WITH_LEN(LocalVarDescriptors,
+                                                          num_entries));
   reader->AddBackRef(object_id, &result, kIsDeserialized);
 
   for (intptr_t i = 0; i < num_entries; i++) {
     (*reader->StringHandle()) ^= reader->ReadObjectImpl(kAsReference);
     result.StorePointer(result.raw()->nameAddrAt(i),
                         reader->StringHandle()->raw());
   }
 
   if (num_entries > 0) {
     NoSafepointScope no_safepoint;
     intptr_t len = num_entries * sizeof(RawLocalVarDescriptors::VarInfo);
     uint8_t* data = result.UnsafeMutableNonPointer(
         reinterpret_cast<const uint8_t*>(result.raw()->data()));
     reader->ReadBytes(data, len);
   }
 
   return result.raw();
 }
 
 
 void RawLocalVarDescriptors::WriteTo(SnapshotWriter* writer,
                                      intptr_t object_id,
                                      Snapshot::Kind kind) {
   ASSERT(writer->snapshot_code());
+  ASSERT(kind == Snapshot::kFull);
 
   // Write out the serialization header value for this object.
   writer->WriteInlinedObjectHeader(object_id);
   writer->WriteIndexedObject(kLocalVarDescriptorsCid);
   writer->WriteTags(writer->GetObjectTags(this));
   writer->Write<int32_t>(ptr()->num_entries_);
   for (intptr_t i = 0; i < ptr()->num_entries_; i++) {
     writer->WriteObjectImpl(ptr()->names()[i], kAsInlinedObject);
   }
   if (ptr()->num_entries_ > 0) {
     intptr_t len = ptr()->num_entries_ * sizeof(VarInfo);
     uint8_t* data = reinterpret_cast<uint8_t*>(this->data());
     writer->WriteBytes(data, len);
   }
 }
 
 
 RawExceptionHandlers* ExceptionHandlers::ReadFrom(SnapshotReader* reader,
                                                   intptr_t object_id,
                                                   intptr_t tags,
                                                   Snapshot::Kind kind) {
-  UNREACHABLE();  // Untested.
   ASSERT(reader->snapshot_code());
+  ASSERT(kind == Snapshot::kFull);
 
-  // handled_types_data.
-  *(reader->ArrayHandle()) ^= reader->ReadObjectImpl(kAsInlinedObject);
-
+  const int32_t num_entries = reader->Read<int32_t>();
   ExceptionHandlers& result =
       ExceptionHandlers::ZoneHandle(reader->zone(),
-        ExceptionHandlers::New(*reader->ArrayHandle()));
+                                    NEW_OBJECT_WITH_LEN(ExceptionHandlers,
+                                                        num_entries));
   reader->AddBackRef(object_id, &result, kIsDeserialized);
 
   if (result.num_entries() > 0) {
     NoSafepointScope no_safepoint;
     const intptr_t len =
         result.num_entries() * sizeof(RawExceptionHandlers::HandlerInfo);
     uint8_t* data = result.UnsafeMutableNonPointer(
         reinterpret_cast<const uint8_t*>(result.raw_ptr()->data()));
     reader->ReadBytes(data, len);
   }
 
+  *(reader->ArrayHandle()) ^= reader->ReadObjectImpl(kAsInlinedObject);
+  result.StorePointer(&result.raw_ptr()->handled_types_data_,
+                      reader->ArrayHandle()->raw());
+
   return result.raw();
 }
 
 
 void RawExceptionHandlers::WriteTo(SnapshotWriter* writer,
                                    intptr_t object_id,
                                    Snapshot::Kind kind) {
   ASSERT(writer->snapshot_code());
+  ASSERT(kind == Snapshot::kFull);
 
   // Write out the serialization header value for this object.
   writer->WriteInlinedObjectHeader(object_id);
   writer->WriteIndexedObject(kExceptionHandlersCid);
   writer->WriteTags(writer->GetObjectTags(this));
-  writer->WriteObjectImpl(ptr()->handled_types_data_, kAsInlinedObject);
+  writer->Write<int32_t>(ptr()->num_entries_);
 
   if (ptr()->num_entries_ > 0) {
     intptr_t len = ptr()->num_entries_ * sizeof(HandlerInfo);
     uint8_t* data = reinterpret_cast<uint8_t*>(ptr()->data());
     writer->WriteBytes(data, len);
   }
+
+  writer->WriteObjectImpl(ptr()->handled_types_data_, kAsInlinedObject);
 }
 
 
 RawContext* Context::ReadFrom(SnapshotReader* reader,
                               intptr_t object_id,
                               intptr_t tags,
                               Snapshot::Kind kind) {
   ASSERT(reader != NULL);
 
   // Allocate context object.
@@ skipping 55 matching lines @@
                               intptr_t object_id,
                               Snapshot::Kind kind) {
   UNREACHABLE();
 }
 
 
 RawICData* ICData::ReadFrom(SnapshotReader* reader,
                             intptr_t object_id,
                             intptr_t tags,
                             Snapshot::Kind kind) {
-  UNREACHABLE();  // Untested.
   ASSERT(reader->snapshot_code());
   ASSERT(kind == Snapshot::kFull);
 
   ICData& result = ICData::ZoneHandle(reader->zone(), NEW_OBJECT(ICData));
   reader->AddBackRef(object_id, &result, kIsDeserialized);
 
   result.set_deopt_id(reader->Read<int32_t>());
   result.set_state_bits(reader->Read<uint32_t>());
 
   // Set all the object fields.
@@ skipping 30 matching lines @@
   // Write out all the object pointer fields.
   SnapshotWriterVisitor visitor(writer);
   visitor.VisitPointers(from(), to());
 }
 
 
 RawMegamorphicCache* MegamorphicCache::ReadFrom(SnapshotReader* reader,
                                                 intptr_t object_id,
                                                 intptr_t tags,
                                                 Snapshot::Kind kind) {
-  UNREACHABLE();  // Untested.
   ASSERT(reader->snapshot_code());
   ASSERT(kind == Snapshot::kFull);
 
   MegamorphicCache& result =
       MegamorphicCache::ZoneHandle(reader->zone(),
                                    NEW_OBJECT(MegamorphicCache));
   reader->AddBackRef(object_id, &result, kIsDeserialized);
 
   result.set_filled_entry_count(reader->Read<int32_t>());
 
@@ skipping 30 matching lines @@
   // Write out all the object pointer fields.
   SnapshotWriterVisitor visitor(writer);
   visitor.VisitPointers(from(), to());
 }
 
 
 RawSubtypeTestCache* SubtypeTestCache::ReadFrom(SnapshotReader* reader,
                                                 intptr_t object_id,
                                                 intptr_t tags,
                                                 Snapshot::Kind kind) {
-  UNREACHABLE();  // Untested.
   ASSERT(reader->snapshot_code());
   ASSERT(kind == Snapshot::kFull);
 
   SubtypeTestCache& result =
       SubtypeTestCache::ZoneHandle(reader->zone(),
                                    NEW_OBJECT(SubtypeTestCache));
   reader->AddBackRef(object_id, &result, kIsDeserialized);
 
   // Set all the object fields.
   // TODO(5411462): Need to assert No GC can happen here, even though
@@ skipping 781 matching lines @@
 
 
 RawLinkedHashMap* LinkedHashMap::ReadFrom(SnapshotReader* reader,
                                           intptr_t object_id,
                                           intptr_t tags,
                                           Snapshot::Kind kind) {
   ASSERT(reader != NULL);
 
   LinkedHashMap& map = LinkedHashMap::ZoneHandle(
       reader->zone(), LinkedHashMap::null());
-  if (kind == Snapshot::kFull || kind == Snapshot::kScript) {
+  if ((kind == Snapshot::kFull && !reader->snapshot_code()) ||
+      kind == Snapshot::kScript) {
     // The immutable maps that seed map literals are not yet VM-internal, so
     // we don't reach this.
     UNREACHABLE();
   } else {
     // Since the map might contain itself as a key or value, allocate first.
-    map = LinkedHashMap::NewUninitialized(HEAP_SPACE(kind));
+    if (kind == Snapshot::kFull) {
+      map = reader->NewLinkedHashMap();
+    } else {
+      map = LinkedHashMap::NewUninitialized(HEAP_SPACE(kind));
+    }
   }
   reader->AddBackRef(object_id, &map, kIsDeserialized);
 
   // Read the type arguments.
   const intptr_t typeargs_offset =
       GrowableObjectArray::type_arguments_offset() / kWordSize;
   *reader->TypeArgumentsHandle() ^=
       reader->ReadObjectImpl(kAsInlinedObject, object_id, typeargs_offset);
   map.SetTypeArguments(*reader->TypeArgumentsHandle());
 
   // Read the number of key/value pairs.
   intptr_t len = reader->ReadSmiValue();
   intptr_t used_data = (len << 1);
   map.SetUsedData(used_data);
 
   // Allocate the data array.
   intptr_t data_size = Utils::Maximum(
       Utils::RoundUpToPowerOfTwo(used_data),
       static_cast<uintptr_t>(LinkedHashMap::kInitialIndexSize));
   Array& data = Array::ZoneHandle(reader->zone(),
-                                  Array::New(data_size, HEAP_SPACE(kind)));
+                                  NEW_OBJECT_WITH_LEN_SPACE(Array,
+                                                            data_size,
+                                                            kind));
   map.SetData(data);
   map.SetDeletedKeys(0);
 
   // The index and hashMask is regenerated by the maps themselves on demand.
   // Thus, the index will probably be allocated in new space (unless it's huge).
   // TODO(koda): Eagerly rehash here when no keys have user-defined '==', and
   // in particular, if/when (const) maps are needed in the VM isolate snapshot.
   ASSERT(reader->isolate() != Dart::vm_isolate());
   map.SetHashMask(0);  // Prefer sentinel 0 over null for better type feedback.
 
   // Read the keys and values.
   bool as_reference = RawObject::IsCanonical(tags) ? false : true;
   for (intptr_t i = 0; i < used_data; i++) {
     *reader->PassiveObjectHandle() = reader->ReadObjectImpl(as_reference);
     data.SetAt(i, *reader->PassiveObjectHandle());
   }
   return map.raw();
 }
 
 
 void RawLinkedHashMap::WriteTo(SnapshotWriter* writer,
                                intptr_t object_id,
                                Snapshot::Kind kind) {
-  if (kind == Snapshot::kFull || kind == Snapshot::kScript) {
+  if ((kind == Snapshot::kFull && !writer->snapshot_code()) ||
+      kind == Snapshot::kScript) {
     // The immutable maps that seed map literals are not yet VM-internal, so
     // we don't reach this.
-    UNREACHABLE();
   }
   ASSERT(writer != NULL);
 
   // Write out the serialization header value for this object.
   writer->WriteInlinedObjectHeader(object_id);
 
   // Write out the class and tags information.
   writer->WriteIndexedObject(kLinkedHashMapCid);
   const uword tags = writer->GetObjectTags(this);
   writer->WriteTags(tags);
@@ skipping 425 matching lines @@
   } else {
     UNREACHABLE();
   }
 }
 
 
 RawSendPort* SendPort::ReadFrom(SnapshotReader* reader,
                                 intptr_t object_id,
                                 intptr_t tags,
                                 Snapshot::Kind kind) {
+  ASSERT(kind == Snapshot::kMessage || reader->snapshot_code());
+
   uint64_t id = reader->Read<uint64_t>();
   uint64_t origin_id = reader->Read<uint64_t>();
 
-  SendPort& result = SendPort::ZoneHandle(reader->zone(),
-                                          SendPort::New(id, origin_id));
+  SendPort& result = SendPort::ZoneHandle(reader->zone());
+  if (reader->snapshot_code()) {
+    // TODO(rmacnak): Reset fields in precompiled snapshots and assert
+    // this is unreachable.
+  } else {
+    result = SendPort::New(id, origin_id);
+  }
   reader->AddBackRef(object_id, &result, kIsDeserialized);
   return result.raw();
 }
 
 
 void RawSendPort::WriteTo(SnapshotWriter* writer,
                           intptr_t object_id,
                           Snapshot::Kind kind) {
   // Write out the serialization header value for this object.
   writer->WriteInlinedObjectHeader(object_id);
@@ skipping 196 matching lines @@
     // We do not allow objects with native fields in an isolate message.
     writer->SetWriteException(Exceptions::kArgument,
                               "Illegal argument in isolate message"
                               " : (object is a UserTag)");
   } else {
     UNREACHABLE();
   }
 }
 
 }  // namespace dart