- Make array immutable first, then canonicalize it.

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 1738 matching lines @@
 
   // Allocate bigint object.
   Bigint& obj = Bigint::ZoneHandle(reader->isolate(), NEW_OBJECT(Bigint));
   reader->AddBackRef(object_id, &obj, kIsDeserialized);
 
   // Set all the object fields.
   // TODO(5411462): Need to assert No GC can happen here, even though
   // allocations may happen.
   intptr_t num_flds = (obj.raw()->to() - obj.raw()->from());
   for (intptr_t i = 0; i <= num_flds; i++) {
-    (*reader->PassiveObjectHandle()) = reader->ReadObjectRef();
+    (*reader->PassiveObjectHandle()) = reader->ReadObjectImpl();
     obj.StorePointer(obj.raw()->from() + i,
                      reader->PassiveObjectHandle()->raw());
   }
 
   // If it is a canonical constant make it one.
   // When reading a full snapshot we don't need to canonicalize the object
   // as it would already be a canonical object.
   // When reading a script snapshot we need to canonicalize only those object
   // references that are objects from the core library (loaded from a
   // full snapshot). Objects that are only in the script need not be
@@ skipping 19 matching lines @@
   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(kBigintCid);
   writer->WriteTags(writer->GetObjectTags(this));
 
   // Write out all the object pointer fields.
-  SnapshotWriterVisitor visitor(writer);
+  SnapshotWriterVisitor visitor(writer, false);
   visitor.VisitPointers(from(), to());
 }
 
 
 RawDouble* Double::ReadFrom(SnapshotReader* reader,
                             intptr_t object_id,
                             intptr_t tags,
                             Snapshot::Kind kind) {
   ASSERT(reader != NULL);
   ASSERT(kind != Snapshot::kMessage);
@@ skipping 291 matching lines @@
 
   // Read the length so that we can determine instance size to allocate.
   intptr_t len = reader->ReadSmiValue();
   Array* array = reinterpret_cast<Array*>(
       reader->GetBackRef(object_id));
   if (array == NULL) {
     array = &(Array::ZoneHandle(reader->isolate(),
                                 NEW_OBJECT_WITH_LEN_SPACE(Array, len, kind)));
     reader->AddBackRef(object_id, array, kIsDeserialized);
   }
+  ASSERT(!RawObject::IsCanonical(tags));
   reader->ArrayReadFrom(*array, len, tags);
   return array->raw();
 }
 
 
 RawImmutableArray* ImmutableArray::ReadFrom(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.
   intptr_t len = reader->ReadSmiValue();
   Array* array = reinterpret_cast<Array*>(reader->GetBackRef(object_id));
   if (array == NULL) {
     array = &(Array::ZoneHandle(
         reader->isolate(),
         NEW_OBJECT_WITH_LEN_SPACE(ImmutableArray, len, kind)));
     reader->AddBackRef(object_id, array, kIsDeserialized);
   }
   reader->ArrayReadFrom(*array, len, tags);
+  if (RawObject::IsCanonical(tags)) {
+    *array ^= array->CheckAndCanonicalize(NULL);
+  }
   return raw(*array);
 }
 
 
 void RawArray::WriteTo(SnapshotWriter* writer,
                        intptr_t object_id,
                        Snapshot::Kind kind) {
+  ASSERT(!RawObject::IsCanonical(writer->GetObjectTags(this)));
   writer->ArrayWriteTo(object_id,
                        kArrayCid,
                        writer->GetObjectTags(this),
                        ptr()->length_,
                        ptr()->type_arguments_,
                        ptr()->data());
 }
 
 
 void RawImmutableArray::WriteTo(SnapshotWriter* writer,
@@ skipping 733 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