src/hotspot/share/oops/oop.cpp

@@ -103,20 +103,20 @@
    if (!Universe::heap()->is_oop(obj)) {
      return false;
    }
  
    // Header verification: the mark is typically non-zero. If we're
-   // at a safepoint, it must not be zero.
+   // at a safepoint, it must not be zero, except when using the new lightweight locking.
    // Outside of a safepoint, the header could be changing (for example,
    // another thread could be inflating a lock on this object).
    if (ignore_mark_word) {
      return true;
    }
    if (obj->mark().value() != 0) {
      return true;
    }
-   return !SafepointSynchronize::is_at_safepoint();
+   return LockingMode == LM_LIGHTWEIGHT || !SafepointSynchronize::is_at_safepoint();
  }
  
  // used only for asserts and guarantees
  bool oopDesc::is_oop_or_null(oop obj, bool ignore_mark_word) {
    return obj == NULL ? true : is_oop(obj, ignore_mark_word);

@@ -137,30 +137,33 @@
  bool oopDesc::is_array_noinline()             const { return is_array();               }
  bool oopDesc::is_objArray_noinline()          const { return is_objArray();            }
  bool oopDesc::is_typeArray_noinline()         const { return is_typeArray();           }
  
  bool oopDesc::has_klass_gap() {
-   // Only has a klass gap when compressed class pointers are used.
-   return UseCompressedClassPointers;
+   // Only has a klass gap when compressed class pointers are used, but
+   // only if not using compact headers..
+   return UseCompressedClassPointers && !UseCompactObjectHeaders;
  }
  
  #if INCLUDE_CDS_JAVA_HEAP
  void oopDesc::set_narrow_klass(narrowKlass nk) {
    assert(DumpSharedSpaces, "Used by CDS only. Do not abuse!");
    assert(UseCompressedClassPointers, "must be");
+   assert(!UseCompactObjectHeaders, "not with compact headers");
    _metadata._compressed_klass = nk;
  }
  #endif
  
  void* oopDesc::load_klass_raw(oop obj) {
-   if (UseCompressedClassPointers) {
-     narrowKlass narrow_klass = obj->_metadata._compressed_klass;
-     if (narrow_klass == 0) return NULL;
-     return (void*)CompressedKlassPointers::decode_raw(narrow_klass);
-   } else {
-     return obj->_metadata._klass;
-   }
+   // TODO: Remove method altogether and replace with calls to obj->klass() ?
+   // OTOH, we may eventually get rid of locking in header, and then no
+   // longer have to deal with that anymore.
+ #ifdef _LP64
+   return obj->klass();
+ #else
+   return obj->_metadata._klass;
+ #endif
  }
  
  void* oopDesc::load_oop_raw(oop obj, int offset) {
    uintptr_t addr = (uintptr_t)(void*)obj + (uint)offset;
    if (UseCompressedOops) {