Split GuardField into GuardFieldType and GuardFieldLength instructions.

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/bigint_operations.h"
 #include "vm/object.h"
 #include "vm/object_store.h"
 #include "vm/snapshot.h"
 #include "vm/stub_code.h"
 #include "vm/symbols.h"
@@ skipping 765 matching lines @@
   field.set_kind_bits(reader->Read<uint8_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 = (field.raw()->to() - field.raw()->from());
   for (intptr_t i = 0; i <= num_flds; i++) {
     *(field.raw()->from() + i) = reader->ReadObjectRef();
   }
 
+  field.InitializeGuardedListLengthInObjectOffset();
+
   return field.raw();
 }
 
 
 void RawField::WriteTo(SnapshotWriter* writer,
                        intptr_t object_id,
                        Snapshot::Kind kind) {
   ASSERT(writer != NULL);
   ASSERT(((kind == Snapshot::kScript) &&
           !RawObject::IsCreatedFromSnapshot(writer->GetObjectTags(this))) ||
@@ skipping 1985 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