1 /*

     2  * Copyright 1997-2007 Sun Microsystems, Inc.  All Rights Reserved.

     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     4  *

     5  * This code is free software; you can redistribute it and/or modify it

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.

     8  *

     9  * This code is distributed in the hope that it will be useful, but WITHOUT

    10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    12  * version 2 for more details (a copy is included in the LICENSE file that

    13  * accompanied this code).

    14  *

    15  * You should have received a copy of the GNU General Public License version

    16  * 2 along with this work; if not, write to the Free Software Foundation,

    17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    18  *

    19  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

    20  * CA 95054 USA or visit www.sun.com if you need additional information or

    21  * have any questions.

    22  *

    23  */

    24 

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

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

    27 // oopDesc is abstract.

    28 // (see oopHierarchy for complete oop class hierarchy)

    29 //

    30 // no virtual functions allowed

    31 

    32 // store into oop with store check

    33 void oop_store(oop* p, oop v);

    34 void oop_store(volatile oop* p, oop v);

    35 

    36 // store into oop without store check

    37 void oop_store_without_check(oop* p, oop v);

    38 void oop_store_without_check(volatile oop* p, oop v);

    39 

    40 

    41 extern bool always_do_update_barrier;

    42 

    43 // Forward declarations.

    44 class OopClosure;

    45 class ScanClosure;

    46 class FastScanClosure;

    47 class FilteringClosure;

    48 class BarrierSet;

    49 class CMSIsAliveClosure;

    50 

    51 class PSPromotionManager;

    52 class ParCompactionManager;

    53 

    54 class oopDesc {

    55   friend class VMStructs;

    56  private:

    57   volatile markOop  _mark;

    58   klassOop _klass;

    59 

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

    61   static BarrierSet* _bs;

    62 

    63  public:

    64   markOop  mark() const         { return _mark; }

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

    66 

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

    68 

    69   void    release_set_mark(markOop m);

    70   markOop cas_set_mark(markOop new_mark, markOop old_mark);

    71 

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

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

    74   void init_mark();

    75 

    76   klassOop klass() const        { return _klass; }

    77   oop* klass_addr() const       { return (oop*) &_klass; }

    78 

    79   void set_klass(klassOop k);

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

    81   void set_klass_to_list_ptr(oop k);

    82 

    83   // size of object header

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

    85   static int header_size_in_bytes() { return sizeof(oopDesc); }

    86 

    87   Klass* blueprint() const;

    88 

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

    90   bool is_a(klassOop k)  const;

    91 

    92   // Returns the actual oop size of the object

    93   int size();

    94 

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

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

    97   int size_given_klass(Klass* klass);

    98 

    99   // Some perm gen objects are not parseble immediately after

   100   // installation of their klass pointer.

   101   bool is_parsable();

   102 

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

   104   bool is_instance()           const;

   105   bool is_instanceRef()        const;

   106   bool is_array()              const;

   107   bool is_objArray()           const;

   108   bool is_symbol()             const;

   109   bool is_klass()              const;

   110   bool is_thread()             const;

   111   bool is_method()             const;

   112   bool is_constMethod()        const;

   113   bool is_methodData()         const;

   114   bool is_constantPool()       const;

   115   bool is_constantPoolCache()  const;

   116   bool is_typeArray()          const;

   117   bool is_javaArray()          const;

   118   bool is_compiledICHolder()   const;

   119 

   120  private:

   121   // field addresses in oop

   122   // byte/char/bool/short fields are always stored as full words

   123   void*     field_base(int offset)        const;

   124 

   125   jbyte*    byte_field_addr(int offset)   const;

   126   jchar*    char_field_addr(int offset)   const;

   127   jboolean* bool_field_addr(int offset)   const;

   128   jint*     int_field_addr(int offset)    const;

   129   jshort*   short_field_addr(int offset)  const;

   130   jlong*    long_field_addr(int offset)   const;

   131   jfloat*   float_field_addr(int offset)  const;

   132   jdouble*  double_field_addr(int offset) const;

   133 

   134  public:

   135   // need this as public for garbage collection

   136   oop* obj_field_addr(int offset) const;

   137 

   138   oop obj_field(int offset) const;

   139   void obj_field_put(int offset, oop value);

   140 

   141   jbyte byte_field(int offset) const;

   142   void byte_field_put(int offset, jbyte contents);

   143 

   144   jchar char_field(int offset) const;

   145   void char_field_put(int offset, jchar contents);

   146 

   147   jboolean bool_field(int offset) const;

   148   void bool_field_put(int offset, jboolean contents);

   149 

   150   jint int_field(int offset) const;

   151   void int_field_put(int offset, jint contents);

   152 

   153   jshort short_field(int offset) const;

   154   void short_field_put(int offset, jshort contents);

   155 

   156   jlong long_field(int offset) const;

   157   void long_field_put(int offset, jlong contents);

   158 

   159   jfloat float_field(int offset) const;

   160   void float_field_put(int offset, jfloat contents);

   161 

   162   jdouble double_field(int offset) const;

   163   void double_field_put(int offset, jdouble contents);

   164 

   165   oop obj_field_acquire(int offset) const;

   166   void release_obj_field_put(int offset, oop value);

   167 

   168   jbyte byte_field_acquire(int offset) const;

   169   void release_byte_field_put(int offset, jbyte contents);

   170 

   171   jchar char_field_acquire(int offset) const;

   172   void release_char_field_put(int offset, jchar contents);

   173 

   174   jboolean bool_field_acquire(int offset) const;

   175   void release_bool_field_put(int offset, jboolean contents);

   176 

   177   jint int_field_acquire(int offset) const;

   178   void release_int_field_put(int offset, jint contents);

   179 

   180   jshort short_field_acquire(int offset) const;

   181   void release_short_field_put(int offset, jshort contents);

   182 

   183   jlong long_field_acquire(int offset) const;

   184   void release_long_field_put(int offset, jlong contents);

   185 

   186   jfloat float_field_acquire(int offset) const;

   187   void release_float_field_put(int offset, jfloat contents);

   188 

   189   jdouble double_field_acquire(int offset) const;

   190   void release_double_field_put(int offset, jdouble contents);

   191 

   192   // printing functions for VM debugging

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

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

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

   196 

   197   // printing on default output stream

   198   void print();

   199   void print_value();

   200   void print_address();

   201 

   202   // return the print strings

   203   char* print_string();

   204   char* print_value_string();

   205 

   206   // verification operations

   207   void verify_on(outputStream* st);

   208   void verify();

   209   void verify_old_oop(oop* p, bool allow_dirty);

   210 

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

   212   bool partially_loaded();

   213   void set_partially_loaded();

   214 

   215   // locking operations

   216   bool is_locked()   const;

   217   bool is_unlocked() const;

   218   bool has_bias_pattern() const;

   219 

   220   // asserts

   221   bool is_oop(bool ignore_mark_word = false) const;

   222   bool is_oop_or_null(bool ignore_mark_word = false) const;

   223 #ifndef PRODUCT

   224   bool is_unlocked_oop() const;

   225 #endif

   226 

   227   // garbage collection

   228   bool is_gc_marked() const;

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

   230   // reference field in "this".

   231   void follow_contents();

   232   void follow_header();

   233 

   234 #ifndef SERIALGC

   235   // Parallel Scavenge

   236   void copy_contents(PSPromotionManager* pm);

   237   void push_contents(PSPromotionManager* pm);

   238 

   239   // Parallel Old

   240   void update_contents(ParCompactionManager* cm);

   241   void update_contents(ParCompactionManager* cm,

   242                        HeapWord* begin_limit,

   243                        HeapWord* end_limit);

   244   void update_contents(ParCompactionManager* cm,

   245                        klassOop old_klass,

   246                        HeapWord* begin_limit,

   247                        HeapWord* end_limit);

   248 

   249   void follow_contents(ParCompactionManager* cm);

   250   void follow_header(ParCompactionManager* cm);

   251 #endif // SERIALGC

   252 

   253   bool is_perm() const;

   254   bool is_perm_or_null() const;

   255   bool is_shared() const;

   256   bool is_shared_readonly() const;

   257   bool is_shared_readwrite() const;

   258 

   259   // Forward pointer operations for scavenge

   260   bool is_forwarded() const;

   261 

   262   void forward_to(oop p);

   263   bool cas_forward_to(oop p, markOop compare);

   264 

   265 #ifndef SERIALGC

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

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

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

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

   270   oop forward_to_atomic(oop p);

   271 #endif // SERIALGC

   272 

   273   oop forwardee() const;

   274 

   275   // Age of object during scavenge

   276   int age() const;

   277   void incr_age();

   278 

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

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

   281   int adjust_pointers();

   282   void adjust_header();

   283 

   284 #ifndef SERIALGC

   285   // Parallel old

   286   void update_header();

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

   288 #endif // SERIALGC

   289 

   290   // mark-sweep support

   291   void follow_body(int begin, int end);

   292 

   293   // Fast access to barrier set

   294   static BarrierSet* bs()            { return _bs; }

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

   296 

   297   // iterators, returns size of object

   298 #define OOP_ITERATE_DECL(OopClosureType, nv_suffix)                             \

   299   int oop_iterate(OopClosureType* blk);                                  \

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

   301 

   302   ALL_OOP_OOP_ITERATE_CLOSURES_1(OOP_ITERATE_DECL)

   303   ALL_OOP_OOP_ITERATE_CLOSURES_3(OOP_ITERATE_DECL)

   304 

   305   void oop_iterate_header(OopClosure* blk);

   306   void oop_iterate_header(OopClosure* blk, MemRegion mr);

   307 

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

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

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

   311   intptr_t identity_hash();

   312   intptr_t slow_identity_hash();

   313 

   314   // marks are forwarded to stack when object is locked

   315   bool     has_displaced_mark() const;

   316   markOop  displaced_mark() const;

   317   void     set_displaced_mark(markOop m);

   318 

   319   // for code generation

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

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

   322 };