hotspot/src/share/vm/oops/klass.hpp
changeset 1 489c9b5090e2
child 360 21d113ecbf6a
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/oops/klass.hpp	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,767 @@
+/*
+ * Copyright 1997-2007 Sun Microsystems, Inc.  All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ */
+
+// A Klass is the part of the klassOop that provides:
+//  1: language level class object (method dictionary etc.)
+//  2: provide vm dispatch behavior for the object
+// Both functions are combined into one C++ class. The toplevel class "Klass"
+// implements purpose 1 whereas all subclasses provide extra virtual functions
+// for purpose 2.
+
+// One reason for the oop/klass dichotomy in the implementation is
+// that we don't want a C++ vtbl pointer in every object.  Thus,
+// normal oops don't have any virtual functions.  Instead, they
+// forward all "virtual" functions to their klass, which does have
+// a vtbl and does the C++ dispatch depending on the object's
+// actual type.  (See oop.inline.hpp for some of the forwarding code.)
+// ALL FUNCTIONS IMPLEMENTING THIS DISPATCH ARE PREFIXED WITH "oop_"!
+
+//  Klass layout:
+//    [header        ] klassOop
+//    [klass pointer ] klassOop
+//    [C++ vtbl ptr  ] (contained in Klass_vtbl)
+//    [layout_helper ]
+//    [super_check_offset   ] for fast subtype checks
+//    [secondary_super_cache] for fast subtype checks
+//    [secondary_supers     ] array of 2ndary supertypes
+//    [primary_supers 0]
+//    [primary_supers 1]
+//    [primary_supers 2]
+//    ...
+//    [primary_supers 7]
+//    [java_mirror   ]
+//    [super         ]
+//    [name          ]
+//    [first subklass]
+//    [next_sibling  ] link to chain additional subklasses
+//    [modifier_flags]
+//    [access_flags  ]
+//    [verify_count  ] - not in product
+//    [alloc_count   ]
+//    [last_biased_lock_bulk_revocation_time] (64 bits)
+//    [prototype_header]
+//    [biased_lock_revocation_count]
+
+
+// Forward declarations.
+class klassVtable;
+class KlassHandle;
+class OrderAccess;
+
+// Holder (or cage) for the C++ vtable of each kind of Klass.
+// We want to tightly constrain the location of the C++ vtable in the overall layout.
+class Klass_vtbl {
+ protected:
+  // The following virtual exists only to force creation of a C++ vtable,
+  // so that this class truly is the location of the vtable of all Klasses.
+  virtual void unused_initial_virtual() { }
+
+ public:
+  // The following virtual makes Klass_vtbl play a second role as a
+  // factory protocol for subclasses of Klass ("sub-Klasses").
+  // Here's how it works....
+  //
+  // This VM uses metaobjects as factories for their instances.
+  //
+  // In order to initialize the C++ vtable of a new instance, its
+  // metaobject is forced to use the C++ placed new operator to
+  // allocate the instance.  In a typical C++-based system, each
+  // sub-class would have its own factory routine which
+  // directly uses the placed new operator on the desired class,
+  // and then calls the appropriate chain of C++ constructors.
+  //
+  // However, this system uses shared code to performs the first
+  // allocation and initialization steps for all sub-Klasses.
+  // (See base_create_klass() and base_create_array_klass().)
+  // This does not factor neatly into a hierarchy of C++ constructors.
+  // Each caller of these shared "base_create" routines knows
+  // exactly which sub-Klass it is creating, but the shared routine
+  // does not, even though it must perform the actual allocation.
+  //
+  // Therefore, the caller of the shared "base_create" must wrap
+  // the specific placed new call in a virtual function which
+  // performs the actual allocation and vtable set-up.  That
+  // virtual function is here, Klass_vtbl::allocate_permanent.
+  //
+  // The arguments to Universe::allocate_permanent() are passed
+  // straight through the placed new operator, which in turn
+  // obtains them directly from this virtual call.
+  //
+  // This virtual is called on a temporary "example instance" of the
+  // sub-Klass being instantiated, a C++ auto variable.  The "real"
+  // instance created by this virtual is on the VM heap, where it is
+  // equipped with a klassOopDesc header.
+  //
+  // It is merely an accident of implementation that we use "example
+  // instances", but that is why the virtual function which implements
+  // each sub-Klass factory happens to be defined by the same sub-Klass
+  // for which it creates instances.
+  //
+  // The vtbl_value() call (see below) is used to strip away the
+  // accidental Klass-ness from an "example instance" and present it as
+  // a factory.  Think of each factory object as a mere container of the
+  // C++ vtable for the desired sub-Klass.  Since C++ does not allow
+  // direct references to vtables, the factory must also be delegated
+  // the task of allocating the instance, but the essential point is
+  // that the factory knows how to initialize the C++ vtable with the
+  // right pointer value.  All other common initializations are handled
+  // by the shared "base_create" subroutines.
+  //
+  virtual void* allocate_permanent(KlassHandle& klass, int size, TRAPS) const = 0;
+  void post_new_init_klass(KlassHandle& klass, klassOop obj, int size) const;
+
+  // Every subclass on which vtbl_value is called must include this macro.
+  // Delay the installation of the klassKlass pointer until after the
+  // the vtable for a new klass has been installed (after the call to new()).
+#define DEFINE_ALLOCATE_PERMANENT(thisKlass) \
+  void* allocate_permanent(KlassHandle& klass_klass, int size, TRAPS) const { \
+    void* result = new(klass_klass, size, THREAD) thisKlass(); \
+    if (HAS_PENDING_EXCEPTION) return NULL;                    \
+    klassOop new_klass = ((Klass*) result)->as_klassOop();      \
+    OrderAccess::storestore();  \
+    post_new_init_klass(klass_klass, new_klass, size);  \
+    return result;      \
+  }
+
+  bool null_vtbl() { return *(intptr_t*)this == 0; }
+
+ protected:
+  void* operator new(size_t ignored, KlassHandle& klass, int size, TRAPS);
+};
+
+
+class Klass : public Klass_vtbl {
+  friend class VMStructs;
+ protected:
+  // note: put frequently-used fields together at start of klass structure
+  // for better cache behavior (may not make much of a difference but sure won't hurt)
+  enum { _primary_super_limit = 8 };
+
+  // The "layout helper" is a combined descriptor of object layout.
+  // For klasses which are neither instance nor array, the value is zero.
+  //
+  // For instances, layout helper is a positive number, the instance size.
+  // This size is already passed through align_object_size and scaled to bytes.
+  // The low order bit is set if instances of this class cannot be
+  // allocated using the fastpath.
+  //
+  // For arrays, layout helper is a negative number, containing four
+  // distinct bytes, as follows:
+  //    MSB:[tag, hsz, ebt, log2(esz)]:LSB
+  // where:
+  //    tag is 0x80 if the elements are oops, 0xC0 if non-oops
+  //    hsz is array header size in bytes (i.e., offset of first element)
+  //    ebt is the BasicType of the elements
+  //    esz is the element size in bytes
+  // This packed word is arranged so as to be quickly unpacked by the
+  // various fast paths that use the various subfields.
+  //
+  // The esz bits can be used directly by a SLL instruction, without masking.
+  //
+  // Note that the array-kind tag looks like 0x00 for instance klasses,
+  // since their length in bytes is always less than 24Mb.
+  //
+  // Final note:  This comes first, immediately after Klass_vtbl,
+  // because it is frequently queried.
+  jint        _layout_helper;
+
+  // The fields _super_check_offset, _secondary_super_cache, _secondary_supers
+  // and _primary_supers all help make fast subtype checks.  See big discussion
+  // in doc/server_compiler/checktype.txt
+  //
+  // Where to look to observe a supertype (it is &_secondary_super_cache for
+  // secondary supers, else is &_primary_supers[depth()].
+  juint       _super_check_offset;
+
+ public:
+  oop* oop_block_beg() const { return adr_secondary_super_cache(); }
+  oop* oop_block_end() const { return adr_next_sibling() + 1; }
+
+ protected:
+  //
+  // The oop block.  All oop fields must be declared here and only oop fields
+  // may be declared here.  In addition, the first and last fields in this block
+  // must remain first and last, unless oop_block_beg() and/or oop_block_end()
+  // are updated.  Grouping the oop fields in a single block simplifies oop
+  // iteration.
+  //
+
+  // Cache of last observed secondary supertype
+  klassOop    _secondary_super_cache;
+  // Array of all secondary supertypes
+  objArrayOop _secondary_supers;
+  // Ordered list of all primary supertypes
+  klassOop    _primary_supers[_primary_super_limit];
+  // java/lang/Class instance mirroring this class
+  oop       _java_mirror;
+  // Superclass
+  klassOop  _super;
+  // Class name.  Instance classes: java/lang/String, etc.  Array classes: [I,
+  // [Ljava/lang/String;, etc.  Set to zero for all other kinds of classes.
+  symbolOop _name;
+  // First subclass (NULL if none); _subklass->next_sibling() is next one
+  klassOop _subklass;
+  // Sibling link (or NULL); links all subklasses of a klass
+  klassOop _next_sibling;
+
+  //
+  // End of the oop block.
+  //
+
+  jint        _modifier_flags;  // Processed access flags, for use by Class.getModifiers.
+  AccessFlags _access_flags;    // Access flags. The class/interface distinction is stored here.
+
+#ifndef PRODUCT
+  int           _verify_count;  // to avoid redundant verifies
+#endif
+
+  juint    _alloc_count;        // allocation profiling support - update klass_size_in_bytes() if moved/deleted
+
+  // Biased locking implementation and statistics
+  // (the 64-bit chunk goes first, to avoid some fragmentation)
+  jlong    _last_biased_lock_bulk_revocation_time;
+  markOop  _prototype_header;   // Used when biased locking is both enabled and disabled for this type
+  jint     _biased_lock_revocation_count;
+
+ public:
+
+  // returns the enclosing klassOop
+  klassOop as_klassOop() const {
+    // see klassOop.hpp for layout.
+    return (klassOop) (((char*) this) - sizeof(klassOopDesc));
+  }
+
+ public:
+  // Allocation
+  const Klass_vtbl& vtbl_value() const { return *this; }  // used only on "example instances"
+  static KlassHandle base_create_klass(KlassHandle& klass, int size, const Klass_vtbl& vtbl, TRAPS);
+  static klassOop base_create_klass_oop(KlassHandle& klass, int size, const Klass_vtbl& vtbl, TRAPS);
+
+  // super
+  klassOop super() const               { return _super; }
+  void set_super(klassOop k)           { oop_store_without_check((oop*) &_super, (oop) k); }
+
+  // initializes _super link, _primary_supers & _secondary_supers arrays
+  void initialize_supers(klassOop k, TRAPS);
+  void initialize_supers_impl1(klassOop k);
+  void initialize_supers_impl2(klassOop k);
+
+  // klass-specific helper for initializing _secondary_supers
+  virtual objArrayOop compute_secondary_supers(int num_extra_slots, TRAPS);
+
+  // java_super is the Java-level super type as specified by Class.getSuperClass.
+  virtual klassOop java_super() const  { return NULL; }
+
+  juint    super_check_offset() const  { return _super_check_offset; }
+  void set_super_check_offset(juint o) { _super_check_offset = o; }
+
+  klassOop secondary_super_cache() const     { return _secondary_super_cache; }
+  void set_secondary_super_cache(klassOop k) { oop_store_without_check((oop*) &_secondary_super_cache, (oop) k); }
+
+  objArrayOop secondary_supers() const { return _secondary_supers; }
+  void set_secondary_supers(objArrayOop k) { oop_store_without_check((oop*) &_secondary_supers, (oop) k); }
+
+  // Return the element of the _super chain of the given depth.
+  // If there is no such element, return either NULL or this.
+  klassOop primary_super_of_depth(juint i) const {
+    assert(i < primary_super_limit(), "oob");
+    klassOop super = _primary_supers[i];
+    assert(super == NULL || super->klass_part()->super_depth() == i, "correct display");
+    return super;
+  }
+
+  // Can this klass be a primary super?  False for interfaces and arrays of
+  // interfaces.  False also for arrays or classes with long super chains.
+  bool can_be_primary_super() const {
+    const juint secondary_offset = secondary_super_cache_offset_in_bytes() + sizeof(oopDesc);
+    return super_check_offset() != secondary_offset;
+  }
+  virtual bool can_be_primary_super_slow() const;
+
+  // Returns number of primary supers; may be a number in the inclusive range [0, primary_super_limit].
+  juint super_depth() const {
+    if (!can_be_primary_super()) {
+      return primary_super_limit();
+    } else {
+      juint d = (super_check_offset() - (primary_supers_offset_in_bytes() + sizeof(oopDesc))) / sizeof(klassOop);
+      assert(d < primary_super_limit(), "oob");
+      assert(_primary_supers[d] == as_klassOop(), "proper init");
+      return d;
+    }
+  }
+
+  // java mirror
+  oop java_mirror() const              { return _java_mirror; }
+  void set_java_mirror(oop m)          { oop_store((oop*) &_java_mirror, m); }
+
+  // modifier flags
+  jint modifier_flags() const          { return _modifier_flags; }
+  void set_modifier_flags(jint flags)  { _modifier_flags = flags; }
+
+  // size helper
+  int layout_helper() const            { return _layout_helper; }
+  void set_layout_helper(int lh)       { _layout_helper = lh; }
+
+  // Note: for instances layout_helper() may include padding.
+  // Use instanceKlass::contains_field_offset to classify field offsets.
+
+  // sub/superklass links
+  instanceKlass* superklass() const;
+  Klass* subklass() const;
+  Klass* next_sibling() const;
+  void append_to_sibling_list();           // add newly created receiver to superklass' subklass list
+  void remove_from_sibling_list();         // remove receiver from sibling list
+ protected:                                // internal accessors
+  klassOop subklass_oop() const            { return _subklass; }
+  klassOop next_sibling_oop() const        { return _next_sibling; }
+  void     set_subklass(klassOop s);
+  void     set_next_sibling(klassOop s);
+
+  oop* adr_super()           const { return (oop*)&_super;             }
+  oop* adr_primary_supers()  const { return (oop*)&_primary_supers[0]; }
+  oop* adr_secondary_super_cache() const { return (oop*)&_secondary_super_cache; }
+  oop* adr_secondary_supers()const { return (oop*)&_secondary_supers;  }
+  oop* adr_java_mirror()     const { return (oop*)&_java_mirror;       }
+  oop* adr_name()            const { return (oop*)&_name;              }
+  oop* adr_subklass()        const { return (oop*)&_subklass;          }
+  oop* adr_next_sibling()    const { return (oop*)&_next_sibling;      }
+
+ public:
+  // Allocation profiling support
+  juint alloc_count() const          { return _alloc_count; }
+  void set_alloc_count(juint n)      { _alloc_count = n; }
+  virtual juint alloc_size() const = 0;
+  virtual void set_alloc_size(juint n) = 0;
+
+  // Compiler support
+  static int super_offset_in_bytes()         { return offset_of(Klass, _super); }
+  static int super_check_offset_offset_in_bytes() { return offset_of(Klass, _super_check_offset); }
+  static int primary_supers_offset_in_bytes(){ return offset_of(Klass, _primary_supers); }
+  static int secondary_super_cache_offset_in_bytes() { return offset_of(Klass, _secondary_super_cache); }
+  static int secondary_supers_offset_in_bytes() { return offset_of(Klass, _secondary_supers); }
+  static int java_mirror_offset_in_bytes()   { return offset_of(Klass, _java_mirror); }
+  static int modifier_flags_offset_in_bytes(){ return offset_of(Klass, _modifier_flags); }
+  static int layout_helper_offset_in_bytes() { return offset_of(Klass, _layout_helper); }
+  static int access_flags_offset_in_bytes()  { return offset_of(Klass, _access_flags); }
+
+  // Unpacking layout_helper:
+  enum {
+    _lh_neutral_value           = 0,  // neutral non-array non-instance value
+    _lh_instance_slow_path_bit  = 0x01,
+    _lh_log2_element_size_shift = BitsPerByte*0,
+    _lh_log2_element_size_mask  = BitsPerLong-1,
+    _lh_element_type_shift      = BitsPerByte*1,
+    _lh_element_type_mask       = right_n_bits(BitsPerByte),  // shifted mask
+    _lh_header_size_shift       = BitsPerByte*2,
+    _lh_header_size_mask        = right_n_bits(BitsPerByte),  // shifted mask
+    _lh_array_tag_bits          = 2,
+    _lh_array_tag_shift         = BitsPerInt - _lh_array_tag_bits,
+    _lh_array_tag_type_value    = ~0x00,  // 0xC0000000 >> 30
+    _lh_array_tag_obj_value     = ~0x01   // 0x80000000 >> 30
+  };
+
+  static int layout_helper_size_in_bytes(jint lh) {
+    assert(lh > (jint)_lh_neutral_value, "must be instance");
+    return (int) lh & ~_lh_instance_slow_path_bit;
+  }
+  static bool layout_helper_needs_slow_path(jint lh) {
+    assert(lh > (jint)_lh_neutral_value, "must be instance");
+    return (lh & _lh_instance_slow_path_bit) != 0;
+  }
+  static bool layout_helper_is_instance(jint lh) {
+    return (jint)lh > (jint)_lh_neutral_value;
+  }
+  static bool layout_helper_is_javaArray(jint lh) {
+    return (jint)lh < (jint)_lh_neutral_value;
+  }
+  static bool layout_helper_is_typeArray(jint lh) {
+    // _lh_array_tag_type_value == (lh >> _lh_array_tag_shift);
+    return (juint)lh >= (juint)(_lh_array_tag_type_value << _lh_array_tag_shift);
+  }
+  static bool layout_helper_is_objArray(jint lh) {
+    // _lh_array_tag_obj_value == (lh >> _lh_array_tag_shift);
+    return (jint)lh < (jint)(_lh_array_tag_type_value << _lh_array_tag_shift);
+  }
+  static int layout_helper_header_size(jint lh) {
+    assert(lh < (jint)_lh_neutral_value, "must be array");
+    int hsize = (lh >> _lh_header_size_shift) & _lh_header_size_mask;
+    assert(hsize > 0 && hsize < (int)sizeof(oopDesc)*3, "sanity");
+    return hsize;
+  }
+  static BasicType layout_helper_element_type(jint lh) {
+    assert(lh < (jint)_lh_neutral_value, "must be array");
+    int btvalue = (lh >> _lh_element_type_shift) & _lh_element_type_mask;
+    assert(btvalue >= T_BOOLEAN && btvalue <= T_OBJECT, "sanity");
+    return (BasicType) btvalue;
+  }
+  static int layout_helper_log2_element_size(jint lh) {
+    assert(lh < (jint)_lh_neutral_value, "must be array");
+    int l2esz = (lh >> _lh_log2_element_size_shift) & _lh_log2_element_size_mask;
+    assert(l2esz <= LogBitsPerLong, "sanity");
+    return l2esz;
+  }
+  static jint array_layout_helper(jint tag, int hsize, BasicType etype, int log2_esize) {
+    return (tag        << _lh_array_tag_shift)
+      |    (hsize      << _lh_header_size_shift)
+      |    ((int)etype << _lh_element_type_shift)
+      |    (log2_esize << _lh_log2_element_size_shift);
+  }
+  static jint instance_layout_helper(jint size, bool slow_path_flag) {
+    return (size << LogHeapWordSize)
+      |    (slow_path_flag ? _lh_instance_slow_path_bit : 0);
+  }
+  static int layout_helper_to_size_helper(jint lh) {
+    assert(lh > (jint)_lh_neutral_value, "must be instance");
+    // Note that the following expression discards _lh_instance_slow_path_bit.
+    return lh >> LogHeapWordSize;
+  }
+  // Out-of-line version computes everything based on the etype:
+  static jint array_layout_helper(BasicType etype);
+
+  // What is the maximum number of primary superclasses any klass can have?
+#ifdef PRODUCT
+  static juint primary_super_limit()         { return _primary_super_limit; }
+#else
+  static juint primary_super_limit() {
+    assert(FastSuperclassLimit <= _primary_super_limit, "parameter oob");
+    return FastSuperclassLimit;
+  }
+#endif
+
+  // vtables
+  virtual klassVtable* vtable() const        { return NULL; }
+
+  static int klass_size_in_bytes()           { return offset_of(Klass, _alloc_count) + sizeof(juint); }  // all "visible" fields
+
+  // subclass check
+  bool is_subclass_of(klassOop k) const;
+  // subtype check: true if is_subclass_of, or if k is interface and receiver implements it
+  bool is_subtype_of(klassOop k) const {
+    juint    off = k->klass_part()->super_check_offset();
+    klassOop sup = *(klassOop*)( (address)as_klassOop() + off );
+    const juint secondary_offset = secondary_super_cache_offset_in_bytes() + sizeof(oopDesc);
+    if (sup == k) {
+      return true;
+    } else if (off != secondary_offset) {
+      return false;
+    } else {
+      return search_secondary_supers(k);
+    }
+  }
+  bool search_secondary_supers(klassOop k) const;
+
+  // Find LCA in class heirarchy
+  Klass *LCA( Klass *k );
+
+  // Check whether reflection/jni/jvm code is allowed to instantiate this class;
+  // if not, throw either an Error or an Exception.
+  virtual void check_valid_for_instantiation(bool throwError, TRAPS);
+
+  // Casting
+  static Klass* cast(klassOop k) {
+    assert(k->is_klass(), "cast to Klass");
+    return k->klass_part();
+  }
+
+  // array copying
+  virtual void  copy_array(arrayOop s, int src_pos, arrayOop d, int dst_pos, int length, TRAPS);
+
+  // tells if the class should be initialized
+  virtual bool should_be_initialized() const    { return false; }
+  // initializes the klass
+  virtual void initialize(TRAPS);
+  // lookup operation for MethodLookupCache
+  friend class MethodLookupCache;
+  virtual methodOop uncached_lookup_method(symbolOop name, symbolOop signature) const;
+ public:
+  methodOop lookup_method(symbolOop name, symbolOop signature) const {
+    return uncached_lookup_method(name, signature);
+  }
+
+  // array class with specific rank
+  klassOop array_klass(int rank, TRAPS)         {  return array_klass_impl(false, rank, THREAD); }
+
+  // array class with this klass as element type
+  klassOop array_klass(TRAPS)                   {  return array_klass_impl(false, THREAD); }
+
+  // These will return NULL instead of allocating on the heap:
+  // NB: these can block for a mutex, like other functions with TRAPS arg.
+  klassOop array_klass_or_null(int rank);
+  klassOop array_klass_or_null();
+
+  virtual oop protection_domain()       { return NULL; }
+  virtual oop class_loader()  const     { return NULL; }
+
+ protected:
+  virtual klassOop array_klass_impl(bool or_null, int rank, TRAPS);
+  virtual klassOop array_klass_impl(bool or_null, TRAPS);
+
+ public:
+  virtual void remove_unshareable_info();
+
+ protected:
+  // computes the subtype relationship
+  virtual bool compute_is_subtype_of(klassOop k);
+ public:
+  // subclass accessor (here for convenience; undefined for non-klass objects)
+  virtual bool is_leaf_class() const { fatal("not a class"); return false; }
+ public:
+  // ALL FUNCTIONS BELOW THIS POINT ARE DISPATCHED FROM AN OOP
+  // These functions describe behavior for the oop not the KLASS.
+
+  // actual oop size of obj in memory
+  virtual int oop_size(oop obj) const = 0;
+
+  // actual oop size of this klass in memory
+  virtual int klass_oop_size() const = 0;
+
+  // Returns the Java name for a class (Resource allocated)
+  // For arrays, this returns the name of the element with a leading '['.
+  // For classes, this returns the name with the package separators
+  //     turned into '.'s.
+  const char* external_name() const;
+  // Returns the name for a class (Resource allocated) as the class
+  // would appear in a signature.
+  // For arrays, this returns the name of the element with a leading '['.
+  // For classes, this returns the name with a leading 'L' and a trailing ';'
+  //     and the package separators as '/'.
+  virtual char* signature_name() const;
+
+  // garbage collection support
+  virtual void oop_follow_contents(oop obj) = 0;
+  virtual int  oop_adjust_pointers(oop obj) = 0;
+
+  // Parallel Scavenge and Parallel Old
+  PARALLEL_GC_DECLS_PV
+
+ public:
+  // type testing operations
+  virtual bool oop_is_instance_slow()       const { return false; }
+  virtual bool oop_is_instanceRef()         const { return false; }
+  virtual bool oop_is_array()               const { return false; }
+  virtual bool oop_is_objArray_slow()       const { return false; }
+  virtual bool oop_is_symbol()              const { return false; }
+  virtual bool oop_is_klass()               const { return false; }
+  virtual bool oop_is_thread()              const { return false; }
+  virtual bool oop_is_method()              const { return false; }
+  virtual bool oop_is_constMethod()         const { return false; }
+  virtual bool oop_is_methodData()          const { return false; }
+  virtual bool oop_is_constantPool()        const { return false; }
+  virtual bool oop_is_constantPoolCache()   const { return false; }
+  virtual bool oop_is_typeArray_slow()      const { return false; }
+  virtual bool oop_is_arrayKlass()          const { return false; }
+  virtual bool oop_is_objArrayKlass()       const { return false; }
+  virtual bool oop_is_typeArrayKlass()      const { return false; }
+  virtual bool oop_is_compiledICHolder()    const { return false; }
+  virtual bool oop_is_instanceKlass()       const { return false; }
+
+  bool oop_is_javaArray_slow() const {
+    return oop_is_objArray_slow() || oop_is_typeArray_slow();
+  }
+
+  // Fast non-virtual versions, used by oop.inline.hpp and elsewhere:
+  #ifndef ASSERT
+  #define assert_same_query(xval, xcheck) xval
+  #else
+ private:
+  static bool assert_same_query(bool xval, bool xslow) {
+    assert(xval == xslow, "slow and fast queries agree");
+    return xval;
+  }
+ public:
+  #endif
+  inline  bool oop_is_instance()            const { return assert_same_query(
+                                                    layout_helper_is_instance(layout_helper()),
+                                                    oop_is_instance_slow()); }
+  inline  bool oop_is_javaArray()           const { return assert_same_query(
+                                                    layout_helper_is_javaArray(layout_helper()),
+                                                    oop_is_javaArray_slow()); }
+  inline  bool oop_is_objArray()            const { return assert_same_query(
+                                                    layout_helper_is_objArray(layout_helper()),
+                                                    oop_is_objArray_slow()); }
+  inline  bool oop_is_typeArray()           const { return assert_same_query(
+                                                    layout_helper_is_typeArray(layout_helper()),
+                                                    oop_is_typeArray_slow()); }
+  #undef assert_same_query
+
+  // Unless overridden, oop is parsable if it has a klass pointer.
+  virtual bool oop_is_parsable(oop obj) const { return true; }
+
+  // Access flags
+  AccessFlags access_flags() const         { return _access_flags;  }
+  void set_access_flags(AccessFlags flags) { _access_flags = flags; }
+
+  bool is_public() const                { return _access_flags.is_public(); }
+  bool is_final() const                 { return _access_flags.is_final(); }
+  bool is_interface() const             { return _access_flags.is_interface(); }
+  bool is_abstract() const              { return _access_flags.is_abstract(); }
+  bool is_super() const                 { return _access_flags.is_super(); }
+  bool is_synthetic() const             { return _access_flags.is_synthetic(); }
+  void set_is_synthetic()               { _access_flags.set_is_synthetic(); }
+  bool has_finalizer() const            { return _access_flags.has_finalizer(); }
+  bool has_final_method() const         { return _access_flags.has_final_method(); }
+  void set_has_finalizer()              { _access_flags.set_has_finalizer(); }
+  void set_has_final_method()           { _access_flags.set_has_final_method(); }
+  bool is_cloneable() const             { return _access_flags.is_cloneable(); }
+  void set_is_cloneable()               { _access_flags.set_is_cloneable(); }
+  bool has_vanilla_constructor() const  { return _access_flags.has_vanilla_constructor(); }
+  void set_has_vanilla_constructor()    { _access_flags.set_has_vanilla_constructor(); }
+  bool has_miranda_methods () const     { return access_flags().has_miranda_methods(); }
+  void set_has_miranda_methods()        { _access_flags.set_has_miranda_methods(); }
+
+  // Biased locking support
+  // Note: the prototype header is always set up to be at least the
+  // prototype markOop. If biased locking is enabled it may further be
+  // biasable and have an epoch.
+  markOop prototype_header() const      { return _prototype_header; }
+  // NOTE: once instances of this klass are floating around in the
+  // system, this header must only be updated at a safepoint.
+  // NOTE 2: currently we only ever set the prototype header to the
+  // biasable prototype for instanceKlasses. There is no technical
+  // reason why it could not be done for arrayKlasses aside from
+  // wanting to reduce the initial scope of this optimization. There
+  // are potential problems in setting the bias pattern for
+  // JVM-internal oops.
+  inline void set_prototype_header(markOop header);
+  static int prototype_header_offset_in_bytes() { return offset_of(Klass, _prototype_header); }
+
+  int  biased_lock_revocation_count() const { return (int) _biased_lock_revocation_count; }
+  // Atomically increments biased_lock_revocation_count and returns updated value
+  int atomic_incr_biased_lock_revocation_count();
+  void set_biased_lock_revocation_count(int val) { _biased_lock_revocation_count = (jint) val; }
+  jlong last_biased_lock_bulk_revocation_time() { return _last_biased_lock_bulk_revocation_time; }
+  void  set_last_biased_lock_bulk_revocation_time(jlong cur_time) { _last_biased_lock_bulk_revocation_time = cur_time; }
+
+
+  // garbage collection support
+  virtual void follow_weak_klass_links(
+    BoolObjectClosure* is_alive, OopClosure* keep_alive);
+
+  // Prefetch within oop iterators.  This is a macro because we
+  // can't guarantee that the compiler will inline it.  In 64-bit
+  // it generally doesn't.  Signature is
+  //
+  // static void prefetch_beyond(oop* const start,
+  //                             oop* const end,
+  //                             const intx foffset,
+  //                             const Prefetch::style pstyle);
+#define prefetch_beyond(start, end, foffset, pstyle) {   \
+    const intx foffset_ = (foffset);                     \
+    const Prefetch::style pstyle_ = (pstyle);            \
+    assert(foffset_ > 0, "prefetch beyond, not behind"); \
+    if (pstyle_ != Prefetch::do_none) {                  \
+      oop* ref = (start);                                \
+      if (ref < (end)) {                                 \
+        switch (pstyle_) {                               \
+        case Prefetch::do_read:                          \
+          Prefetch::read(*ref, foffset_);                \
+          break;                                         \
+        case Prefetch::do_write:                         \
+          Prefetch::write(*ref, foffset_);               \
+          break;                                         \
+        default:                                         \
+          ShouldNotReachHere();                          \
+          break;                                         \
+        }                                                \
+      }                                                  \
+    }                                                    \
+  }
+
+  // iterators
+  virtual int oop_oop_iterate(oop obj, OopClosure* blk) = 0;
+  virtual int oop_oop_iterate_v(oop obj, OopClosure* blk) {
+    return oop_oop_iterate(obj, blk);
+  }
+
+  // Iterates "blk" over all the oops in "obj" (of type "this") within "mr".
+  // (I don't see why the _m should be required, but without it the Solaris
+  // C++ gives warning messages about overridings of the "oop_oop_iterate"
+  // defined above "hiding" this virtual function.  (DLD, 6/20/00)) */
+  virtual int oop_oop_iterate_m(oop obj, OopClosure* blk, MemRegion mr) = 0;
+  virtual int oop_oop_iterate_v_m(oop obj, OopClosure* blk, MemRegion mr) {
+    return oop_oop_iterate_m(obj, blk, mr);
+  }
+
+  // Versions of the above iterators specialized to particular subtypes
+  // of OopClosure, to avoid closure virtual calls.
+#define Klass_OOP_OOP_ITERATE_DECL(OopClosureType, nv_suffix)                \
+  virtual int oop_oop_iterate##nv_suffix(oop obj, OopClosureType* blk) {     \
+    /* Default implementation reverts to general version. */                 \
+    return oop_oop_iterate(obj, blk);                                        \
+  }                                                                          \
+                                                                             \
+  /* Iterates "blk" over all the oops in "obj" (of type "this") within "mr". \
+     (I don't see why the _m should be required, but without it the Solaris  \
+     C++ gives warning messages about overridings of the "oop_oop_iterate"   \
+     defined above "hiding" this virtual function.  (DLD, 6/20/00)) */       \
+  virtual int oop_oop_iterate##nv_suffix##_m(oop obj,                        \
+                                             OopClosureType* blk,            \
+                                             MemRegion mr) {                 \
+    return oop_oop_iterate_m(obj, blk, mr);                                  \
+  }
+
+  SPECIALIZED_OOP_OOP_ITERATE_CLOSURES_1(Klass_OOP_OOP_ITERATE_DECL)
+  SPECIALIZED_OOP_OOP_ITERATE_CLOSURES_3(Klass_OOP_OOP_ITERATE_DECL)
+
+  virtual void array_klasses_do(void f(klassOop k)) {}
+  virtual void with_array_klasses_do(void f(klassOop k));
+
+  // Return self, except for abstract classes with exactly 1
+  // implementor.  Then return the 1 concrete implementation.
+  Klass *up_cast_abstract();
+
+  // klass name
+  symbolOop name() const                   { return _name; }
+  void set_name(symbolOop n)               { oop_store_without_check((oop*) &_name, (oop) n); }
+
+  friend class klassKlass;
+
+ public:
+  // jvm support
+  virtual jint compute_modifier_flags(TRAPS) const;
+
+ public:
+  // JVMTI support
+  virtual jint jvmti_class_status() const;
+
+#ifndef PRODUCT
+ public:
+  // Printing
+  virtual void oop_print_on      (oop obj, outputStream* st);
+  virtual void oop_print_value_on(oop obj, outputStream* st);
+#endif
+
+ public:
+  // Verification
+  virtual const char* internal_name() const = 0;
+  virtual void oop_verify_on(oop obj, outputStream* st);
+  virtual void oop_verify_old_oop(oop obj, oop* p, bool allow_dirty);
+  // tells whether obj is partially constructed (gc during class loading)
+  virtual bool oop_partially_loaded(oop obj) const { return false; }
+  virtual void oop_set_partially_loaded(oop obj) {};
+
+#ifndef PRODUCT
+  void verify_vtable_index(int index);
+#endif
+};