src/hotspot/share/classfile/placeholders.hpp

*** 72,85 ****
  // LOAD_SUPER needed to check for class circularity
  // DEFINE_CLASS: ultimately define class must be single threaded
  // on a class/classloader basis
  // so the head of that queue owns the token
  // and the rest of the threads return the result the first thread gets
   enum classloadAction {
      LOAD_INSTANCE = 1,             // calling load_instance_class
      LOAD_SUPER = 2,                // loading superclass for this class
!     DEFINE_CLASS = 3               // find_or_define class
   };
  
    // find_and_add returns probe pointer - old or new
    // If no entry exists, add a placeholder entry and push SeenThread for classloadAction
    // If entry exists, reuse entry and push SeenThread for classloadAction
--- 72,87 ----
  // LOAD_SUPER needed to check for class circularity
  // DEFINE_CLASS: ultimately define class must be single threaded
  // on a class/classloader basis
  // so the head of that queue owns the token
  // and the rest of the threads return the result the first thread gets
+ // FLATTENABLE_FIELD: needed to check for value type flattenable fields circularity
   enum classloadAction {
      LOAD_INSTANCE = 1,             // calling load_instance_class
      LOAD_SUPER = 2,                // loading superclass for this class
!     DEFINE_CLASS = 3,              // find_or_define class
!     FLATTENABLE_FIELD = 4          // flattenable value type fields
   };
  
    // find_and_add returns probe pointer - old or new
    // If no entry exists, add a placeholder entry and push SeenThread for classloadAction
    // If entry exists, reuse entry and push SeenThread for classloadAction
*** 107,116 ****
--- 109,120 ----
  // For bootclasssearchpath, set before calling load_instance_class.
  // Defining must be single threaded on a class/classloader basis
  // For DEFINE_CLASS, the head of the queue owns the
  // define token and the rest of the threads wait to return the
  // result the first thread gets.
+ // For FLATTENABLE_FIELD, set when loading value type fields for
+ // class circularity checking.
  class SeenThread: public CHeapObj<mtInternal> {
  private:
     Thread *_thread;
     SeenThread* _stnext;
     SeenThread* _stprev;
*** 158,167 ****
--- 162,172 ----
  
    SeenThread*       _defineThreadQ; // queue of Threads trying to define this class
                                      // including _definer
                                      // _definer owns token
                                      // queue waits for and returns results from _definer
+   SeenThread*       _flattenableFieldQ; // queue of value types for circularity checking
  
   public:
    // Simple accessors, used only by SystemDictionary
    Symbol*            klassname()           const { return literal(); }
  
*** 190,199 ****
--- 195,207 ----
    void               set_loadInstanceThreadQ(SeenThread* SeenThread) { _loadInstanceThreadQ = SeenThread; }
  
    SeenThread*        defineThreadQ()        const { return _defineThreadQ; }
    void               set_defineThreadQ(SeenThread* SeenThread) { _defineThreadQ = SeenThread; }
  
+   SeenThread*        flattenableFieldQ()    const { return _flattenableFieldQ; }
+   void               set_flattenableFieldQ(SeenThread* SeenThread) { _flattenableFieldQ = SeenThread; }
+ 
    PlaceholderEntry* next() const {
      return (PlaceholderEntry*)HashtableEntry<Symbol*, mtClass>::next();
    }
  
    PlaceholderEntry** next_addr() {
*** 216,225 ****
--- 224,236 ----
           queuehead = _superThreadQ;
           break;
        case PlaceholderTable::DEFINE_CLASS:
           queuehead = _defineThreadQ;
           break;
+       case PlaceholderTable::FLATTENABLE_FIELD:
+          queuehead = _flattenableFieldQ;
+          break;
        default: Unimplemented();
      }
      return queuehead;
    }
  
*** 232,241 ****
--- 243,255 ----
           _superThreadQ = seenthread;
           break;
        case PlaceholderTable::DEFINE_CLASS:
           _defineThreadQ = seenthread;
           break;
+       case PlaceholderTable::FLATTENABLE_FIELD:
+          _flattenableFieldQ = seenthread;
+          break;
        default: Unimplemented();
      }
      return;
    }
  
*** 249,258 ****
--- 263,276 ----
  
    bool define_class_in_progress() {
      return (_defineThreadQ != NULL);
    }
  
+   bool flattenable_field_in_progress() {
+     return (_flattenableFieldQ != NULL);
+   }
+ 
  // Doubly-linked list of Threads per action for class/classloader pair
  // Class circularity support: links in thread before loading superclass
  // bootstrapsearchpath support: links in a thread before load_instance_class
  // definers: use as queue of define requestors, including owner of
  // define token. Appends for debugging of requestor order