Update subclasses array and is_implemented bit when loading script snapshots.

runtime/vm/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/snapshot.h"
 
 #include "platform/assert.h"
 #include "vm/bootstrap.h"
 #include "vm/class_finalizer.h"
 #include "vm/dart.h"
@@ skipping 224 matching lines @@
     PassiveObject& obj =
         PassiveObject::Handle(zone(), ReadObjectImpl(kAsInlinedObject));
     for (intptr_t i = 0; i < backward_references_->length(); i++) {
       if (!(*backward_references_)[i].is_deserialized()) {
         ReadObjectImpl(kAsInlinedObject);
         (*backward_references_)[i].set_state(kIsDeserialized);
       }
     }
     if (backward_references_->length() > 0) {
       ProcessDeferredCanonicalizations();
+      FixSubclassesAndImplementors();

[siva, 2017/06/12 22:59:42]

should only be done when kind == kScript?

This path is also executed for kind == kMessage.

[rmacnak, 2017/06/12 23:37:42]

Yes, added check for kScript

       return (*backward_references_)[0].reference()->raw();
     } else {
       return obj.raw();
     }
   } else {
     // An error occurred while reading, return the error object.
     const Error& err = Error::Handle(thread()->sticky_error());
     thread()->clear_sticky_error();
     return err.raw();
   }
@@ skipping 975 matching lines @@
           }
         }
       } else {
         ASSERT(objref->IsCanonical());
       }
     }
   }
 }
 
 
+void SnapshotReader::FixSubclassesAndImplementors() {
+  Class& cls = Class::Handle(zone());
+  Class& supercls = Class::Handle(zone());
+  Array& interfaces = Array::Handle(zone());
+  AbstractType& interface = AbstractType::Handle(zone());
+  Class& interface_cls = Class::Handle(zone());
+  for (intptr_t i = 0; i < backward_references_->length(); i++) {
+    BackRefNode& backref = (*backward_references_)[i];
+    Object* objref = backref.reference();
+    if (objref->IsClass()) {
+      cls ^= objref->raw();
+      if (!cls.IsInFullSnapshot()) {
+        supercls = cls.SuperClass();
+        if (!supercls.IsNull() && !supercls.IsObjectClass() &&
+            supercls.IsInFullSnapshot()) {
+          supercls.AddDirectSubclass(cls);
+          supercls.DisableCHAOptimizedCode(cls);
+        }
+        interfaces = cls.interfaces();
+        for (intptr_t i = 0; i < interfaces.Length(); i++) {
+          interface ^= interfaces.At(i);
+          interface_cls = interface.type_class();
+          interface_cls.set_is_implemented();
+          interface_cls.DisableCHAOptimizedCode(cls);
+        }
+      }
+    }
+  }
+}
+
+
 void SnapshotReader::ArrayReadFrom(intptr_t object_id,
                                    const Array& result,
                                    intptr_t len,
                                    intptr_t tags) {
   // Setup the object fields.
   const intptr_t typeargs_offset =
       GrowableObjectArray::type_arguments_offset() / kWordSize;
   *TypeArgumentsHandle() ^=
       ReadObjectImpl(kAsInlinedObject, object_id, typeargs_offset);
   result.SetTypeArguments(*TypeArgumentsHandle());
@@ skipping 760 matching lines @@
       *buffer_len_ = BytesWritten();
     }
   } else {
     FreeBuffer();
     ThrowException(exception_type(), exception_msg());
   }
 }
 
 
 }  // namespace dart