Add a VM defined class MirrorReference as an opaque pointer for Dart code to VM internal objects.

runtime/vm/raw_object_snapshot.cc

Index: runtime/vm/raw_object_snapshot.cc
===================================================================
--- runtime/vm/raw_object_snapshot.cc	(revision 24540)
+++ runtime/vm/raw_object_snapshot.cc	(working copy)
@@ -2646,4 +2646,42 @@
   writer->Write<RawObject*>(ptr()->value_);
 }
 
+
+RawVMReference* VMReference::ReadFrom(SnapshotReader* reader,
+                                      intptr_t object_id,
+                                      intptr_t tags,
+                                      Snapshot::Kind kind) {
+  ASSERT(reader != NULL);
+
+  // Allocate the weak property object.
+  VMReference& vm_reference = VMReference::ZoneHandle(
+      reader->isolate(), VMReference::New(HEAP_SPACE(kind)));
+  reader->AddBackRef(object_id, &vm_reference, kIsDeserialized);
+
+  // Set the object tags.
+  vm_reference.set_tags(tags);
+
+  // Set all the object fields.
+  vm_reference.raw_ptr()->referent_ = reader->ReadObject();

[siva, 2013/06/30 01:12:48]

(*reader->ObjectHandle()) = reader->ReadObjectImpl();
vm_reference.set_referent(*reader->ObjectHandle());


(that way you get the StorePointer stuff).

[rmacnak, 2013/07/01 18:35:49]

Changed

+
+  return vm_reference.raw();
+}
+
+
+void RawVMReference::WriteTo(SnapshotWriter* writer,
+                             intptr_t object_id,
+                             Snapshot::Kind kind) {
+  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(kVMReferenceCid);
+  writer->WriteIntptrValue(writer->GetObjectTags(this));
+
+  // Write out all the other fields.
+  writer->WriteObject(ptr()->referent_);

[siva, 2013/06/30 01:12:48]

writer->WriteObjectImpl(ptr()->referent_);

[rmacnak, 2013/07/01 18:35:49]

Changed. Required adding RawVMReference as a friend class.

+}

[siva, 2013/06/30 01:12:48]

Need to add unit tests in snapshot_test.cc so that these methods get
exercised...

+
 }  // namespace dart