src/hotspot/share/oops/instanceMirrorKlass.cpp

@@ -49,21 +49,29 @@
      return align_object_size(size_helper() + InstanceKlass::cast(k)->static_field_size());
    }
    return size_helper();
  }
  
- instanceOop InstanceMirrorKlass::allocate_instance(Klass* k, TRAPS) {
+ instanceOop InstanceMirrorKlass::allocate_instance(Klass* k, bool extend, TRAPS) {
    // Query before forming handle.
-   size_t size = instance_size(k);
-   assert(size > 0, "total object size must be non-zero: " SIZE_FORMAT, size);
+   size_t base_size = instance_size(k);
+   size_t size = base_size;
+   if (extend && UseCompactObjectHeaders) {
+     size = align_object_size(size + 1);
+   }
+   assert(base_size > 0, "base object size must be non-zero: " SIZE_FORMAT, base_size);
  
    // Since mirrors can be variable sized because of the static fields, store
    // the size in the mirror itself.
-   return (instanceOop)Universe::heap()->class_allocate(this, size, THREAD);
+   instanceOop obj = (instanceOop)Universe::heap()->class_allocate(this, size, base_size, THREAD);
+   if (extend && UseCompactObjectHeaders) {
+     obj->set_mark(obj->mark().set_not_hashed_expanded());
+   }
+   return obj;
  }
  
- size_t InstanceMirrorKlass::oop_size(oop obj) const {
+ size_t InstanceMirrorKlass::oop_size(oop obj, markWord mark) const {
    return java_lang_Class::oop_size(obj);
  }
  
  int InstanceMirrorKlass::compute_static_oop_field_count(oop obj) {
    Klass* k = java_lang_Class::as_Klass(obj);

@@ -71,10 +79,20 @@
      return InstanceKlass::cast(k)->static_oop_field_count();
    }
    return 0;
  }
  
+ int InstanceMirrorKlass::hash_offset_in_bytes(oop obj) const {
+   assert(UseCompactObjectHeaders, "only with compact i-hash");
+   // TODO: There may be gaps that we could use, e.g. in the fields of Class,
+   // between the fields of Class and the static fields or in or at the end of
+   // the static fields block.
+   // When implementing any change here, make sure that allocate_instance()
+   // and corresponding code in InstanceMirrorKlass.java are in sync.
+   return checked_cast<int>(obj->base_size_given_klass(obj->mark(), this) * BytesPerWord);
+ }
+ 
  #if INCLUDE_CDS
  void InstanceMirrorKlass::serialize_offsets(SerializeClosure* f) {
    f->do_int(&_offset_of_static_fields);
  }
  #endif