private void recordConcreteType (VM_Method m, VM_Field f, VM_TypeReference t) {
private synchronized static void recordConcreteType (VM_Method m, VM_Field f, VM_TypeReference t) {
  private void recordConcreteType (VM_Method m, VM_Field f, VM_TypeReference t) {    // for now, only track private fields    if (!f.isPrivate())      return;    OPT_FieldDatabase.FieldDatabaseEntry entry = db.findOrCreateEntry(f);    OPT_FieldDatabase.FieldWriterInfo info = entry.findMethodInfo(m);    info.setAnalyzed();    if (info.isBottom())      return;    VM_TypeReference oldType = info.concreteType;    if (oldType == null) {      // set a new concrete type for this field.      info.concreteType = t;    } else if (oldType != t) {      // we've previously determined a DIFFERENT! concrete type.      // meet the two types: ie., change it to bottom.      info.setBottom();    }  }