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 /*

  * Copyright (c) 1997, 2009, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

  * or visit www.oracle.com if you need additional information or have any

  * questions.

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  */

 // oopDesc is the top baseclass for objects classes.  The {name}Desc classes describe

 // the format of Java objects so the fields can be accessed from C++.

 // oopDesc is abstract.

 // (see oopHierarchy for complete oop class hierarchy)

 //

 // no virtual functions allowed

 // store into oop with store check

 template <class T> inline void oop_store(T* p, oop v);

 template <class T> inline void oop_store(volatile T* p, oop v);

 // store into oop without store check

 template <class T> inline void oop_store_without_check(T* p, oop v);

 template <class T> inline void oop_store_without_check(volatile T* p, oop v);

 extern bool always_do_update_barrier;

 // Forward declarations.

 class OopClosure;

 class ScanClosure;

 class FastScanClosure;

 class FilteringClosure;

 class BarrierSet;

 class CMSIsAliveClosure;

 class PSPromotionManager;

 class ParCompactionManager;

 class oopDesc {

   friend class VMStructs;

  private:

   volatile markOop  _mark;

   union _metadata {

     wideKlassOop    _klass;

     narrowOop       _compressed_klass;

   } _metadata;

   // Fast access to barrier set.  Must be initialized.

   static BarrierSet* _bs;

  public:

   markOop  mark() const         { return _mark; }

   markOop* mark_addr() const    { return (markOop*) &_mark; }

   void set_mark(volatile markOop m)      { _mark = m;   }

   void    release_set_mark(markOop m);

   markOop cas_set_mark(markOop new_mark, markOop old_mark);

   // Used only to re-initialize the mark word (e.g., of promoted

   // objects during a GC) -- requires a valid klass pointer

   void init_mark();

   klassOop klass() const;

   klassOop klass_or_null() const volatile;

   oop* klass_addr();

   narrowOop* compressed_klass_addr();

   void set_klass(klassOop k);

   // For klass field compression

   int klass_gap() const;

   void set_klass_gap(int z);

   // For when the klass pointer is being used as a linked list "next" field.

   void set_klass_to_list_ptr(oop k);

   // size of object header, aligned to platform wordSize

   static int header_size()          { return sizeof(oopDesc)/HeapWordSize; }

   Klass* blueprint() const;

   // Returns whether this is an instance of k or an instance of a subclass of k

   bool is_a(klassOop k)  const;

   // Returns the actual oop size of the object

   int size();

   // Sometimes (for complicated concurrency-related reasons), it is useful

   // to be able to figure out the size of an object knowing its klass.

   int size_given_klass(Klass* klass);

   // Some perm gen objects are not parseble immediately after

   // installation of their klass pointer.

   bool is_parsable();

   // Some perm gen objects that have been allocated and initialized

   // can be changed by the VM when not at a safe point (class rededfinition

   // is an example).  Such objects should not be examined by the

   // concurrent processing of a garbage collector if is_conc_safe()

   // returns false.

   bool is_conc_safe();

   // type test operations (inlined in oop.inline.h)

   bool is_instance()           const;

   bool is_instanceRef()        const;

   bool is_array()              const;

   bool is_objArray()           const;

   bool is_symbol()             const;

   bool is_klass()              const;

   bool is_thread()             const;

   bool is_method()             const;

   bool is_constMethod()        const;

   bool is_methodData()         const;

   bool is_constantPool()       const;

   bool is_constantPoolCache()  const;

   bool is_typeArray()          const;

   bool is_javaArray()          const;

   bool is_compiledICHolder()   const;

  private:

   // field addresses in oop

   void*     field_base(int offset)        const;

   jbyte*    byte_field_addr(int offset)   const;

   jchar*    char_field_addr(int offset)   const;

   jboolean* bool_field_addr(int offset)   const;

   jint*     int_field_addr(int offset)    const;

   jshort*   short_field_addr(int offset)  const;

   jlong*    long_field_addr(int offset)   const;

   jfloat*   float_field_addr(int offset)  const;

   jdouble*  double_field_addr(int offset) const;

   address*  address_field_addr(int offset) const;

  public:

   // Need this as public for garbage collection.

   template <class T> T* obj_field_addr(int offset) const;

   static bool is_null(oop obj);

   static bool is_null(narrowOop obj);

   // Decode an oop pointer from a narrowOop if compressed.

   // These are overloaded for oop and narrowOop as are the other functions

   // below so that they can be called in template functions.

   static oop decode_heap_oop_not_null(oop v);

   static oop decode_heap_oop_not_null(narrowOop v);

   static oop decode_heap_oop(oop v);

   static oop decode_heap_oop(narrowOop v);

   // Encode an oop pointer to a narrow oop.  The or_null versions accept

   // null oop pointer, others do not in order to eliminate the

   // null checking branches.

   static narrowOop encode_heap_oop_not_null(oop v);

   static narrowOop encode_heap_oop(oop v);

   // Load an oop out of the Java heap

   static narrowOop load_heap_oop(narrowOop* p);

   static oop       load_heap_oop(oop* p);

   // Load an oop out of Java heap and decode it to an uncompressed oop.

   static oop load_decode_heap_oop_not_null(narrowOop* p);

   static oop load_decode_heap_oop_not_null(oop* p);

   static oop load_decode_heap_oop(narrowOop* p);

   static oop load_decode_heap_oop(oop* p);

   // Store an oop into the heap.

   static void store_heap_oop(narrowOop* p, narrowOop v);

   static void store_heap_oop(oop* p, oop v);

   // Encode oop if UseCompressedOops and store into the heap.

   static void encode_store_heap_oop_not_null(narrowOop* p, oop v);

   static void encode_store_heap_oop_not_null(oop* p, oop v);

   static void encode_store_heap_oop(narrowOop* p, oop v);

   static void encode_store_heap_oop(oop* p, oop v);

   static void release_store_heap_oop(volatile narrowOop* p, narrowOop v);

   static void release_store_heap_oop(volatile oop* p, oop v);

   static void release_encode_store_heap_oop_not_null(volatile narrowOop* p, oop v);

   static void release_encode_store_heap_oop_not_null(volatile oop* p, oop v);

   static void release_encode_store_heap_oop(volatile narrowOop* p, oop v);

   static void release_encode_store_heap_oop(volatile oop* p, oop v);

   static oop atomic_exchange_oop(oop exchange_value, volatile HeapWord *dest);

   static oop atomic_compare_exchange_oop(oop exchange_value,

                                          volatile HeapWord *dest,

                                          oop compare_value);

   // Access to fields in a instanceOop through these methods.

   oop obj_field(int offset) const;

   void obj_field_put(int offset, oop value);

   void obj_field_raw_put(int offset, oop value);

   jbyte byte_field(int offset) const;

   void byte_field_put(int offset, jbyte contents);

   jchar char_field(int offset) const;

   void char_field_put(int offset, jchar contents);

   jboolean bool_field(int offset) const;

   void bool_field_put(int offset, jboolean contents);

   jint int_field(int offset) const;

   void int_field_put(int offset, jint contents);

   jshort short_field(int offset) const;

   void short_field_put(int offset, jshort contents);

   jlong long_field(int offset) const;

   void long_field_put(int offset, jlong contents);

   jfloat float_field(int offset) const;

   void float_field_put(int offset, jfloat contents);

   jdouble double_field(int offset) const;

   void double_field_put(int offset, jdouble contents);

   address address_field(int offset) const;

   void address_field_put(int offset, address contents);

   oop obj_field_acquire(int offset) const;

   void release_obj_field_put(int offset, oop value);

   jbyte byte_field_acquire(int offset) const;

   void release_byte_field_put(int offset, jbyte contents);

   jchar char_field_acquire(int offset) const;

   void release_char_field_put(int offset, jchar contents);

   jboolean bool_field_acquire(int offset) const;

   void release_bool_field_put(int offset, jboolean contents);

   jint int_field_acquire(int offset) const;

   void release_int_field_put(int offset, jint contents);

   jshort short_field_acquire(int offset) const;

   void release_short_field_put(int offset, jshort contents);

   jlong long_field_acquire(int offset) const;

   void release_long_field_put(int offset, jlong contents);

   jfloat float_field_acquire(int offset) const;

   void release_float_field_put(int offset, jfloat contents);

   jdouble double_field_acquire(int offset) const;

   void release_double_field_put(int offset, jdouble contents);

   address address_field_acquire(int offset) const;

   void release_address_field_put(int offset, address contents);

   // printing functions for VM debugging

   void print_on(outputStream* st) const;         // First level print

   void print_value_on(outputStream* st) const;   // Second level print.

   void print_address_on(outputStream* st) const; // Address printing

   // printing on default output stream

   void print();

   void print_value();

   void print_address();

   // return the print strings

   char* print_string();

   char* print_value_string();

   // verification operations

   void verify_on(outputStream* st);

   void verify();

   void verify_old_oop(oop* p, bool allow_dirty);

   void verify_old_oop(narrowOop* p, bool allow_dirty);

   // tells whether this oop is partially constructed (gc during class loading)

   bool partially_loaded();

   void set_partially_loaded();

   // locking operations

   bool is_locked()   const;

   bool is_unlocked() const;

   bool has_bias_pattern() const;

   // asserts

   bool is_oop(bool ignore_mark_word = false) const;

   bool is_oop_or_null(bool ignore_mark_word = false) const;

 #ifndef PRODUCT

   bool is_unlocked_oop() const;

 #endif

   // garbage collection

   bool is_gc_marked() const;

   // Apply "MarkSweep::mark_and_push" to (the address of) every non-NULL

   // reference field in "this".

   void follow_contents(void);

   void follow_header(void);

 #ifndef SERIALGC

   // Parallel Scavenge

   void push_contents(PSPromotionManager* pm);

   // Parallel Old

   void update_contents(ParCompactionManager* cm);

   void update_contents(ParCompactionManager* cm,

                        HeapWord* begin_limit,

                        HeapWord* end_limit);

   void update_contents(ParCompactionManager* cm,

                        klassOop old_klass,

                        HeapWord* begin_limit,

                        HeapWord* end_limit);

   void follow_contents(ParCompactionManager* cm);

   void follow_header(ParCompactionManager* cm);

 #endif // SERIALGC

   bool is_perm() const;

   bool is_perm_or_null() const;

   bool is_scavengable() const;

   bool is_shared() const;

   bool is_shared_readonly() const;

   bool is_shared_readwrite() const;

   // Forward pointer operations for scavenge

   bool is_forwarded() const;

   void forward_to(oop p);

   bool cas_forward_to(oop p, markOop compare);

 #ifndef SERIALGC

   // Like "forward_to", but inserts the forwarding pointer atomically.

   // Exactly one thread succeeds in inserting the forwarding pointer, and

   // this call returns "NULL" for that thread; any other thread has the

   // value of the forwarding pointer returned and does not modify "this".

   oop forward_to_atomic(oop p);

 #endif // SERIALGC

   oop forwardee() const;

   // Age of object during scavenge

   int age() const;

   void incr_age();

   // Adjust all pointers in this object to point at it's forwarded location and

   // return the size of this oop.  This is used by the MarkSweep collector.

   int adjust_pointers();

   void adjust_header();

 #ifndef SERIALGC

   // Parallel old

   void update_header();

   void update_header(HeapWord* beg_addr, HeapWord* end_addr);

 #endif // SERIALGC

   // mark-sweep support

   void follow_body(int begin, int end);

   // Fast access to barrier set

   static BarrierSet* bs()            { return _bs; }

   static void set_bs(BarrierSet* bs) { _bs = bs; }

   // iterators, returns size of object

 #define OOP_ITERATE_DECL(OopClosureType, nv_suffix)                      \

   int oop_iterate(OopClosureType* blk);                                  \

   int oop_iterate(OopClosureType* blk, MemRegion mr);  // Only in mr.

   ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_DECL)

   ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_DECL)

 #ifndef SERIALGC

 #define OOP_ITERATE_BACKWARDS_DECL(OopClosureType, nv_suffix)            \

   int oop_iterate_backwards(OopClosureType* blk);

   ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_BACKWARDS_DECL)

   ALL_OOP_OOP_ITERATE_CLOSURES_2(OOP_ITERATE_BACKWARDS_DECL)

 #endif

   void oop_iterate_header(OopClosure* blk);

   void oop_iterate_header(OopClosure* blk, MemRegion mr);

   // identity hash; returns the identity hash key (computes it if necessary)

   // NOTE with the introduction of UseBiasedLocking that identity_hash() might reach a

   // safepoint if called on a biased object. Calling code must be aware of that.

   intptr_t identity_hash();

   intptr_t slow_identity_hash();

   // marks are forwarded to stack when object is locked

   bool     has_displaced_mark() const;

   markOop  displaced_mark() const;

   void     set_displaced_mark(markOop m);

   // for code generation

   static int mark_offset_in_bytes()    { return offset_of(oopDesc, _mark); }

   static int klass_offset_in_bytes()   { return offset_of(oopDesc, _metadata._klass); }

   static int klass_gap_offset_in_bytes();

 };