Small optimization in shared class loading:

http://hg.openjdk.java.net/jdk/jdk/file/7ef41e83066b/src/hotspot/share/classfile/systemDictionary.cpp#l1281

In SystemDictionary::load_shared_class() we call resolve_super_or_fail to check if the super types of a shared class has been redefined at run time. However, this requires looking up the super types by name.

  if (ik->super() != NULL) {
    Symbol* cn = ik->super()->name();
    Klass *s = resolve_super_or_fail(class_name, ....)

We can avoid the look up altogether if the super type has already been loaded. Something like this:

  if (ik->super() != NULL) {
     if (ik->super() is shared class for boot/platform/app loaders) {
       if (ik->super()->class_loader_data() != NULL) {
           // We known for sure that the super class has been loaded from
           // CDS, so it's not redefined.
      } else {
        resolve_super_or_fail(....)
      }