1 /*
   2  * Copyright (c) 1997, 2012, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_VM_OOPS_INSTANCEKLASS_HPP
  26 #define SHARE_VM_OOPS_INSTANCEKLASS_HPP
  27 
  28 #include "classfile/classLoaderData.hpp"
  29 #include "oops/annotations.hpp"
  30 #include "oops/constMethod.hpp"
  31 #include "oops/fieldInfo.hpp"
  32 #include "oops/instanceOop.hpp"
  33 #include "oops/klassVtable.hpp"
  34 #include "runtime/handles.hpp"
  35 #include "runtime/os.hpp"
  36 #include "utilities/accessFlags.hpp"
  37 #include "utilities/bitMap.inline.hpp"
  38 
  39 // An InstanceKlass is the VM level representation of a Java class.
  40 // It contains all information needed for at class at execution runtime.
  41 
  42 //  InstanceKlass layout:
  43 //    [C++ vtbl pointer           ] Klass
  44 //    [subtype cache              ] Klass
  45 //    [instance size              ] Klass
  46 //    [java mirror                ] Klass
  47 //    [super                      ] Klass
  48 //    [access_flags               ] Klass
  49 //    [name                       ] Klass
  50 //    [first subklass             ] Klass
  51 //    [next sibling               ] Klass
  52 //    [array klasses              ]
  53 //    [methods                    ]
  54 //    [local interfaces           ]
  55 //    [transitive interfaces      ]
  56 //    [fields                     ]
  57 //    [constants                  ]
  58 //    [class loader               ]
  59 //    [protection domain          ]
  60 //    [signers                    ]
  61 //    [source file name           ]
  62 //    [inner classes              ]
  63 //    [static field size          ]
  64 //    [nonstatic field size       ]
  65 //    [static oop fields size     ]
  66 //    [nonstatic oop maps size    ]
  67 //    [has finalize method        ]
  68 //    [deoptimization mark bit    ]
  69 //    [initialization state       ]
  70 //    [initializing thread        ]
  71 //    [Java vtable length         ]
  72 //    [oop map cache (stack maps) ]
  73 //    [EMBEDDED Java vtable             ] size in words = vtable_len
  74 //    [EMBEDDED nonstatic oop-map blocks] size in words = nonstatic_oop_map_size
  75 //      The embedded nonstatic oop-map blocks are short pairs (offset, length)
  76 //      indicating where oops are located in instances of this klass.
  77 //    [EMBEDDED implementor of the interface] only exist for interface
  78 //    [EMBEDDED host klass        ] only exist for an anonymous class (JSR 292 enabled)
  79 
  80 
  81 // forward declaration for class -- see below for definition
  82 class SuperTypeClosure;
  83 class JNIid;
  84 class jniIdMapBase;
  85 class BreakpointInfo;
  86 class fieldDescriptor;
  87 class DepChange;
  88 class nmethodBucket;
  89 class PreviousVersionNode;
  90 class JvmtiCachedClassFieldMap;
  91 
  92 // This is used in iterators below.
  93 class FieldClosure: public StackObj {
  94 public:
  95   virtual void do_field(fieldDescriptor* fd) = 0;
  96 };
  97 
  98 #ifndef PRODUCT
  99 // Print fields.
 100 // If "obj" argument to constructor is NULL, prints static fields, otherwise prints non-static fields.
 101 class FieldPrinter: public FieldClosure {
 102    oop _obj;
 103    outputStream* _st;
 104  public:
 105    FieldPrinter(outputStream* st, oop obj = NULL) : _obj(obj), _st(st) {}
 106    void do_field(fieldDescriptor* fd);
 107 };
 108 #endif  // !PRODUCT
 109 
 110 // ValueObjs embedded in klass. Describes where oops are located in instances of
 111 // this klass.
 112 class OopMapBlock VALUE_OBJ_CLASS_SPEC {
 113  public:
 114   // Byte offset of the first oop mapped by this block.
 115   int offset() const          { return _offset; }
 116   void set_offset(int offset) { _offset = offset; }
 117 
 118   // Number of oops in this block.
 119   uint count() const         { return _count; }
 120   void set_count(uint count) { _count = count; }
 121 
 122   // sizeof(OopMapBlock) in HeapWords.
 123   static const int size_in_words() {
 124     return align_size_up(int(sizeof(OopMapBlock)), HeapWordSize) >>
 125       LogHeapWordSize;
 126   }
 127 
 128  private:
 129   int  _offset;
 130   uint _count;
 131 };
 132 
 133 class InstanceKlass: public Klass {
 134   friend class VMStructs;
 135   friend class ClassFileParser;
 136   friend class CompileReplay;
 137 
 138  protected:
 139   // Constructor
 140   InstanceKlass(int vtable_len,
 141                 int itable_len,
 142                 int static_field_size,
 143                 int nonstatic_oop_map_size,
 144                 ReferenceType rt,
 145                 AccessFlags access_flags,
 146                 bool is_anonymous);
 147  public:
 148   static Klass* allocate_instance_klass(ClassLoaderData* loader_data,
 149                                           int vtable_len,
 150                                           int itable_len,
 151                                           int static_field_size,
 152                                           int nonstatic_oop_map_size,
 153                                           ReferenceType rt,
 154                                           AccessFlags access_flags,
 155                                           Symbol* name,
 156                                         Klass* super_klass,
 157                                           KlassHandle host_klass,
 158                                           TRAPS);
 159 
 160   InstanceKlass() { assert(DumpSharedSpaces || UseSharedSpaces, "only for CDS"); }
 161 
 162   // See "The Java Virtual Machine Specification" section 2.16.2-5 for a detailed description
 163   // of the class loading & initialization procedure, and the use of the states.
 164   enum ClassState {
 165     allocated,                          // allocated (but not yet linked)
 166     loaded,                             // loaded and inserted in class hierarchy (but not linked yet)
 167     linked,                             // successfully linked/verified (but not initialized yet)
 168     being_initialized,                  // currently running class initializer
 169     fully_initialized,                  // initialized (successfull final state)
 170     initialization_error                // error happened during initialization
 171   };
 172 
 173  protected:
 174   // Protection domain.
 175   oop             _protection_domain;
 176   // Class signers.
 177   objArrayOop     _signers;
 178   // Initialization lock.  Must be one per class and it has to be a VM internal
 179   // object so java code cannot lock it (like the mirror)
 180   // It has to be an object not a Mutex because it's held through java calls.
 181   volatile oop    _init_lock;
 182 
 183   // Annotations for this class
 184   Annotations*    _annotations;
 185   // Array classes holding elements of this class.
 186   Klass*          _array_klasses;
 187   // Constant pool for this class.
 188   ConstantPool* _constants;
 189   // The InnerClasses attribute and EnclosingMethod attribute. The
 190   // _inner_classes is an array of shorts. If the class has InnerClasses
 191   // attribute, then the _inner_classes array begins with 4-tuples of shorts
 192   // [inner_class_info_index, outer_class_info_index,
 193   // inner_name_index, inner_class_access_flags] for the InnerClasses
 194   // attribute. If the EnclosingMethod attribute exists, it occupies the
 195   // last two shorts [class_index, method_index] of the array. If only
 196   // the InnerClasses attribute exists, the _inner_classes array length is
 197   // number_of_inner_classes * 4. If the class has both InnerClasses
 198   // and EnclosingMethod attributes the _inner_classes array length is
 199   // number_of_inner_classes * 4 + enclosing_method_attribute_size.
 200   Array<jushort>* _inner_classes;
 201 
 202   // Name of source file containing this klass, NULL if not specified.
 203   Symbol*         _source_file_name;
 204   // the source debug extension for this klass, NULL if not specified.
 205   // Specified as UTF-8 string without terminating zero byte in the classfile,
 206   // it is stored in the instanceklass as a NULL-terminated UTF-8 string
 207   char*           _source_debug_extension;
 208   // Generic signature, or null if none.
 209   Symbol*         _generic_signature;
 210   // Array name derived from this class which needs unreferencing
 211   // if this class is unloaded.
 212   Symbol*         _array_name;
 213 
 214   // Number of heapOopSize words used by non-static fields in this klass
 215   // (including inherited fields but after header_size()).
 216   int             _nonstatic_field_size;
 217   int             _static_field_size;    // number words used by static fields (oop and non-oop) in this klass
 218   u2              _static_oop_field_count;// number of static oop fields in this klass
 219   u2              _java_fields_count;    // The number of declared Java fields
 220   int             _nonstatic_oop_map_size;// size in words of nonstatic oop map blocks
 221 
 222   bool            _is_marked_dependent;  // used for marking during flushing and deoptimization
 223   enum {
 224     _misc_rewritten            = 1 << 0, // methods rewritten.
 225     _misc_has_nonstatic_fields = 1 << 1, // for sizing with UseCompressedOops
 226     _misc_should_verify_class  = 1 << 2, // allow caching of preverification
 227     _misc_is_anonymous         = 1 << 3  // has embedded _inner_classes field
 228   };
 229   u2              _misc_flags;
 230   u2              _minor_version;        // minor version number of class file
 231   u2              _major_version;        // major version number of class file
 232   Thread*         _init_thread;          // Pointer to current thread doing initialization (to handle recusive initialization)
 233   int             _vtable_len;           // length of Java vtable (in words)
 234   int             _itable_len;           // length of Java itable (in words)
 235   OopMapCache*    volatile _oop_map_cache;   // OopMapCache for all methods in the klass (allocated lazily)
 236   JNIid*          _jni_ids;              // First JNI identifier for static fields in this class
 237   jmethodID*      _methods_jmethod_ids;  // jmethodIDs corresponding to method_idnum, or NULL if none
 238   int*            _methods_cached_itable_indices;  // itable_index cache for JNI invoke corresponding to methods idnum, or NULL
 239   nmethodBucket*  _dependencies;         // list of dependent nmethods
 240   nmethod*        _osr_nmethods_head;    // Head of list of on-stack replacement nmethods for this class
 241   BreakpointInfo* _breakpoints;          // bpt lists, managed by Method*
 242   // Array of interesting part(s) of the previous version(s) of this
 243   // InstanceKlass. See PreviousVersionWalker below.
 244   GrowableArray<PreviousVersionNode *>* _previous_versions;
 245   // JVMTI fields can be moved to their own structure - see 6315920
 246   unsigned char * _cached_class_file_bytes;       // JVMTI: cached class file, before retransformable agent modified it in CFLH
 247   jint            _cached_class_file_len;         // JVMTI: length of above
 248   JvmtiCachedClassFieldMap* _jvmti_cached_class_field_map;  // JVMTI: used during heap iteration
 249 
 250   // true if class, superclass, or implemented interfaces have default methods
 251   bool            _has_default_methods;
 252 
 253   volatile u2     _idnum_allocated_count;         // JNI/JVMTI: increments with the addition of methods, old ids don't change
 254   // Method array.
 255   Array<Method*>* _methods;
 256   // Interface (Klass*s) this class declares locally to implement.
 257   Array<Klass*>* _local_interfaces;
 258   // Interface (Klass*s) this class implements transitively.
 259   Array<Klass*>* _transitive_interfaces;
 260   // Int array containing the original order of method in the class file (for JVMTI).
 261   Array<int>*     _method_ordering;
 262   // Instance and static variable information, starts with 6-tuples of shorts
 263   // [access, name index, sig index, initval index, low_offset, high_offset]
 264   // for all fields, followed by the generic signature data at the end of
 265   // the array. Only fields with generic signature attributes have the generic
 266   // signature data set in the array. The fields array looks like following:
 267   //
 268   // f1: [access, name index, sig index, initial value index, low_offset, high_offset]
 269   // f2: [access, name index, sig index, initial value index, low_offset, high_offset]
 270   //      ...
 271   // fn: [access, name index, sig index, initial value index, low_offset, high_offset]
 272   //     [generic signature index]
 273   //     [generic signature index]
 274   //     ...
 275   Array<u2>*      _fields;
 276 
 277   // Class states are defined as ClassState (see above).
 278   // Place the _init_state here to utilize the unused 2-byte after
 279   // _idnum_allocated_count.
 280   u1              _init_state;                    // state of class
 281 
 282   u1              _reference_type;                // reference type
 283 
 284   // embedded Java vtable follows here
 285   // embedded Java itables follows here
 286   // embedded static fields follows here
 287   // embedded nonstatic oop-map blocks follows here
 288   // embedded implementor of this interface follows here
 289   //   The embedded implementor only exists if the current klass is an
 290   //   iterface. The possible values of the implementor fall into following
 291   //   three cases:
 292   //     NULL: no implementor.
 293   //     A Klass* that's not itself: one implementor.
 294   //     Itsef: more than one implementors.
 295   // embedded host klass follows here
 296   //   The embedded host klass only exists in an anonymous class for
 297   //   dynamic language support (JSR 292 enabled). The host class grants
 298   //   its access privileges to this class also. The host class is either
 299   //   named, or a previously loaded anonymous class. A non-anonymous class
 300   //   or an anonymous class loaded through normal classloading does not
 301   //   have this embedded field.
 302   //
 303 
 304   friend class SystemDictionary;
 305 
 306  public:
 307   bool has_nonstatic_fields() const        {
 308     return (_misc_flags & _misc_has_nonstatic_fields) != 0;
 309   }
 310   void set_has_nonstatic_fields(bool b)    {
 311     if (b) {
 312       _misc_flags |= _misc_has_nonstatic_fields;
 313     } else {
 314       _misc_flags &= ~_misc_has_nonstatic_fields;
 315     }
 316   }
 317 
 318   // field sizes
 319   int nonstatic_field_size() const         { return _nonstatic_field_size; }
 320   void set_nonstatic_field_size(int size)  { _nonstatic_field_size = size; }
 321 
 322   int static_field_size() const            { return _static_field_size; }
 323   void set_static_field_size(int size)     { _static_field_size = size; }
 324 
 325   int static_oop_field_count() const       { return (int)_static_oop_field_count; }
 326   void set_static_oop_field_count(u2 size) { _static_oop_field_count = size; }
 327 
 328   // Java vtable
 329   int  vtable_length() const               { return _vtable_len; }
 330   void set_vtable_length(int len)          { _vtable_len = len; }
 331 
 332   // Java itable
 333   int  itable_length() const               { return _itable_len; }
 334   void set_itable_length(int len)          { _itable_len = len; }
 335 
 336   // array klasses
 337   Klass* array_klasses() const             { return _array_klasses; }
 338   void set_array_klasses(Klass* k)         { _array_klasses = k; }
 339 
 340   // methods
 341   Array<Method*>* methods() const          { return _methods; }
 342   void set_methods(Array<Method*>* a)      { _methods = a; }
 343   Method* method_with_idnum(int idnum);
 344 
 345   // method ordering
 346   Array<int>* method_ordering() const     { return _method_ordering; }
 347   void set_method_ordering(Array<int>* m) { _method_ordering = m; }
 348 
 349   // interfaces
 350   Array<Klass*>* local_interfaces() const          { return _local_interfaces; }
 351   void set_local_interfaces(Array<Klass*>* a)      {
 352     guarantee(_local_interfaces == NULL || a == NULL, "Just checking");
 353     _local_interfaces = a; }
 354   Array<Klass*>* transitive_interfaces() const     { return _transitive_interfaces; }
 355   void set_transitive_interfaces(Array<Klass*>* a) {
 356     guarantee(_transitive_interfaces == NULL || a == NULL, "Just checking");
 357     _transitive_interfaces = a; }
 358 
 359  private:
 360   friend class fieldDescriptor;
 361   FieldInfo* field(int index) const { return FieldInfo::from_field_array(_fields, index); }
 362 
 363  public:
 364   int     field_offset      (int index) const { return field(index)->offset(); }
 365   int     field_access_flags(int index) const { return field(index)->access_flags(); }
 366   Symbol* field_name        (int index) const { return field(index)->name(constants()); }
 367   Symbol* field_signature   (int index) const { return field(index)->signature(constants()); }
 368 
 369   // Number of Java declared fields
 370   int java_fields_count() const           { return (int)_java_fields_count; }
 371 
 372   Array<u2>* fields() const            { return _fields; }
 373 
 374   void set_fields(Array<u2>* f, u2 java_fields_count) {
 375     guarantee(_fields == NULL || f == NULL, "Just checking");
 376     _fields =  f;
 377     _java_fields_count = java_fields_count;
 378   }
 379 
 380   // inner classes
 381   Array<u2>* inner_classes() const       { return _inner_classes; }
 382   void set_inner_classes(Array<u2>* f)   { _inner_classes = f; }
 383 
 384   enum InnerClassAttributeOffset {
 385     // From http://mirror.eng/products/jdk/1.1/docs/guide/innerclasses/spec/innerclasses.doc10.html#18814
 386     inner_class_inner_class_info_offset = 0,
 387     inner_class_outer_class_info_offset = 1,
 388     inner_class_inner_name_offset = 2,
 389     inner_class_access_flags_offset = 3,
 390     inner_class_next_offset = 4
 391   };
 392 
 393   enum EnclosingMethodAttributeOffset {
 394     enclosing_method_class_index_offset = 0,
 395     enclosing_method_method_index_offset = 1,
 396     enclosing_method_attribute_size = 2
 397   };
 398 
 399   // method override check
 400   bool is_override(methodHandle super_method, Handle targetclassloader, Symbol* targetclassname, TRAPS);
 401 
 402   // package
 403   bool is_same_class_package(Klass* class2);
 404   bool is_same_class_package(oop classloader2, Symbol* classname2);
 405   static bool is_same_class_package(oop class_loader1, Symbol* class_name1, oop class_loader2, Symbol* class_name2);
 406 
 407   // find an enclosing class (defined where original code was, in jvm.cpp!)
 408   Klass* compute_enclosing_class(bool* inner_is_member, TRAPS) {
 409     instanceKlassHandle self(THREAD, this);
 410     return compute_enclosing_class_impl(self, inner_is_member, THREAD);
 411   }
 412   static Klass* compute_enclosing_class_impl(instanceKlassHandle self,
 413                                                bool* inner_is_member, TRAPS);
 414 
 415   // tell if two classes have the same enclosing class (at package level)
 416   bool is_same_package_member(Klass* class2, TRAPS) {
 417     instanceKlassHandle self(THREAD, this);
 418     return is_same_package_member_impl(self, class2, THREAD);
 419   }
 420   static bool is_same_package_member_impl(instanceKlassHandle self,
 421                                           Klass* class2, TRAPS);
 422 
 423   // initialization state
 424   bool is_loaded() const                   { return _init_state >= loaded; }
 425   bool is_linked() const                   { return _init_state >= linked; }
 426   bool is_initialized() const              { return _init_state == fully_initialized; }
 427   bool is_not_initialized() const          { return _init_state <  being_initialized; }
 428   bool is_being_initialized() const        { return _init_state == being_initialized; }
 429   bool is_in_error_state() const           { return _init_state == initialization_error; }
 430   bool is_reentrant_initialization(Thread *thread)  { return thread == _init_thread; }
 431   ClassState  init_state()                 { return (ClassState)_init_state; }
 432   bool is_rewritten() const                { return (_misc_flags & _misc_rewritten) != 0; }
 433 
 434   // defineClass specified verification
 435   bool should_verify_class() const         {
 436     return (_misc_flags & _misc_should_verify_class) != 0;
 437   }
 438   void set_should_verify_class(bool value) {
 439     if (value) {
 440       _misc_flags |= _misc_should_verify_class;
 441     } else {
 442       _misc_flags &= ~_misc_should_verify_class;
 443     }
 444   }
 445 
 446   // marking
 447   bool is_marked_dependent() const         { return _is_marked_dependent; }
 448   void set_is_marked_dependent(bool value) { _is_marked_dependent = value; }
 449 
 450   // initialization (virtuals from Klass)
 451   bool should_be_initialized() const;  // means that initialize should be called
 452   void initialize(TRAPS);
 453   void link_class(TRAPS);
 454   bool link_class_or_fail(TRAPS); // returns false on failure
 455   void unlink_class();
 456   void rewrite_class(TRAPS);
 457   void relocate_and_link_methods(TRAPS);
 458   Method* class_initializer();
 459 
 460   // set the class to initialized if no static initializer is present
 461   void eager_initialize(Thread *thread);
 462 
 463   // reference type
 464   ReferenceType reference_type() const     { return (ReferenceType)_reference_type; }
 465   void set_reference_type(ReferenceType t) {
 466     assert(t == (u1)t, "overflow");
 467     _reference_type = (u1)t;
 468   }
 469 
 470   static ByteSize reference_type_offset() { return in_ByteSize(offset_of(InstanceKlass, _reference_type)); }
 471 
 472   // find local field, returns true if found
 473   bool find_local_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const;
 474   // find field in direct superinterfaces, returns the interface in which the field is defined
 475   Klass* find_interface_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const;
 476   // find field according to JVM spec 5.4.3.2, returns the klass in which the field is defined
 477   Klass* find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const;
 478   // find instance or static fields according to JVM spec 5.4.3.2, returns the klass in which the field is defined
 479   Klass* find_field(Symbol* name, Symbol* sig, bool is_static, fieldDescriptor* fd) const;
 480 
 481   // find a non-static or static field given its offset within the class.
 482   bool contains_field_offset(int offset) {
 483     return instanceOopDesc::contains_field_offset(offset, nonstatic_field_size());
 484   }
 485 
 486   bool find_local_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const;
 487   bool find_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const;
 488 
 489   // find a local method (returns NULL if not found)
 490   Method* find_method(Symbol* name, Symbol* signature) const;
 491   static Method* find_method(Array<Method*>* methods, Symbol* name, Symbol* signature);
 492 
 493   // lookup operation (returns NULL if not found)
 494   Method* uncached_lookup_method(Symbol* name, Symbol* signature) const;
 495 
 496   // lookup a method in all the interfaces that this class implements
 497   // (returns NULL if not found)
 498   Method* lookup_method_in_all_interfaces(Symbol* name, Symbol* signature) const;
 499 
 500   // Find method indices by name.  If a method with the specified name is
 501   // found the index to the first method is returned, and 'end' is filled in
 502   // with the index of first non-name-matching method.  If no method is found
 503   // -1 is returned.
 504   int find_method_by_name(Symbol* name, int* end);
 505   static int find_method_by_name(Array<Method*>* methods, Symbol* name, int* end);
 506 
 507   // constant pool
 508   ConstantPool* constants() const        { return _constants; }
 509   void set_constants(ConstantPool* c)    { _constants = c; }
 510 
 511   // protection domain
 512   oop protection_domain()                  { return _protection_domain; }
 513   void set_protection_domain(oop pd)       { klass_oop_store(&_protection_domain, pd); }
 514 
 515   // host class
 516   Klass* host_klass() const              {
 517     Klass** hk = (Klass**)adr_host_klass();
 518     if (hk == NULL) {
 519       return NULL;
 520     } else {
 521       return *hk;
 522     }
 523   }
 524   void set_host_klass(Klass* host)            {
 525     assert(is_anonymous(), "not anonymous");
 526     Klass** addr = (Klass**)adr_host_klass();
 527     assert(addr != NULL, "no reversed space");
 528     *addr = host;
 529   }
 530   bool is_anonymous() const                {
 531     return (_misc_flags & _misc_is_anonymous) != 0;
 532   }
 533   void set_is_anonymous(bool value)        {
 534     if (value) {
 535       _misc_flags |= _misc_is_anonymous;
 536     } else {
 537       _misc_flags &= ~_misc_is_anonymous;
 538     }
 539   }
 540 
 541   // Oop that keeps the metadata for this class from being unloaded
 542   // in places where the metadata is stored in other places, like nmethods
 543   oop klass_holder() const {
 544     return is_anonymous() ? java_mirror() : class_loader();
 545   }
 546 
 547   // signers
 548   objArrayOop signers() const              { return _signers; }
 549   void set_signers(objArrayOop s)          { klass_oop_store((oop*)&_signers, s); }
 550 
 551   // source file name
 552   Symbol* source_file_name() const         { return _source_file_name; }
 553   void set_source_file_name(Symbol* n);
 554 
 555   // minor and major version numbers of class file
 556   u2 minor_version() const                 { return _minor_version; }
 557   void set_minor_version(u2 minor_version) { _minor_version = minor_version; }
 558   u2 major_version() const                 { return _major_version; }
 559   void set_major_version(u2 major_version) { _major_version = major_version; }
 560 
 561   // source debug extension
 562   char* source_debug_extension() const     { return _source_debug_extension; }
 563   void set_source_debug_extension(char* array, int length);
 564 
 565   // symbol unloading support (refcount already added)
 566   Symbol* array_name()                     { return _array_name; }
 567   void set_array_name(Symbol* name)        { assert(_array_name == NULL, "name already created"); _array_name = name; }
 568 
 569   // nonstatic oop-map blocks
 570   static int nonstatic_oop_map_size(unsigned int oop_map_count) {
 571     return oop_map_count * OopMapBlock::size_in_words();
 572   }
 573   unsigned int nonstatic_oop_map_count() const {
 574     return _nonstatic_oop_map_size / OopMapBlock::size_in_words();
 575   }
 576   int nonstatic_oop_map_size() const { return _nonstatic_oop_map_size; }
 577   void set_nonstatic_oop_map_size(int words) {
 578     _nonstatic_oop_map_size = words;
 579   }
 580 
 581   // RedefineClasses() support for previous versions:
 582   void add_previous_version(instanceKlassHandle ikh, BitMap *emcp_methods,
 583          int emcp_method_count);
 584   // If the _previous_versions array is non-NULL, then this klass
 585   // has been redefined at least once even if we aren't currently
 586   // tracking a previous version.
 587   bool has_been_redefined() const { return _previous_versions != NULL; }
 588   bool has_previous_version() const;
 589   void init_previous_versions() {
 590     _previous_versions = NULL;
 591   }
 592   GrowableArray<PreviousVersionNode *>* previous_versions() const {
 593     return _previous_versions;
 594   }
 595 
 596   static void purge_previous_versions(InstanceKlass* ik);
 597 
 598   // JVMTI: Support for caching a class file before it is modified by an agent that can do retransformation
 599   void set_cached_class_file(unsigned char *class_file_bytes,
 600                              jint class_file_len)     { _cached_class_file_len = class_file_len;
 601                                                         _cached_class_file_bytes = class_file_bytes; }
 602   jint get_cached_class_file_len()                    { return _cached_class_file_len; }
 603   unsigned char * get_cached_class_file_bytes()       { return _cached_class_file_bytes; }
 604 
 605   // JVMTI: Support for caching of field indices, types, and offsets
 606   void set_jvmti_cached_class_field_map(JvmtiCachedClassFieldMap* descriptor) {
 607     _jvmti_cached_class_field_map = descriptor;
 608   }
 609   JvmtiCachedClassFieldMap* jvmti_cached_class_field_map() const {
 610     return _jvmti_cached_class_field_map;
 611   }
 612 
 613   bool has_default_methods() const { return _has_default_methods; }
 614   void set_has_default_methods(bool b) { _has_default_methods = b; }
 615 
 616   // for adding methods, ConstMethod::UNSET_IDNUM means no more ids available
 617   inline u2 next_method_idnum();
 618   void set_initial_method_idnum(u2 value)             { _idnum_allocated_count = value; }
 619 
 620   // generics support
 621   Symbol* generic_signature() const                   { return _generic_signature; }
 622   void set_generic_signature(Symbol* sig)             { _generic_signature = sig; }
 623 
 624   u2 enclosing_method_data(int offset);
 625   u2 enclosing_method_class_index() {
 626     return enclosing_method_data(enclosing_method_class_index_offset);
 627   }
 628   u2 enclosing_method_method_index() {
 629     return enclosing_method_data(enclosing_method_method_index_offset);
 630   }
 631   void set_enclosing_method_indices(u2 class_index,
 632                                     u2 method_index);
 633 
 634   // jmethodID support
 635   static jmethodID get_jmethod_id(instanceKlassHandle ik_h,
 636                      methodHandle method_h);
 637   static jmethodID get_jmethod_id_fetch_or_update(instanceKlassHandle ik_h,
 638                      size_t idnum, jmethodID new_id, jmethodID* new_jmeths,
 639                      jmethodID* to_dealloc_id_p,
 640                      jmethodID** to_dealloc_jmeths_p);
 641   static void get_jmethod_id_length_value(jmethodID* cache, size_t idnum,
 642                 size_t *length_p, jmethodID* id_p);
 643   jmethodID jmethod_id_or_null(Method* method);
 644 
 645   // cached itable index support
 646   void set_cached_itable_index(size_t idnum, int index);
 647   int cached_itable_index(size_t idnum);
 648 
 649   // annotations support
 650   Annotations* annotations() const          { return _annotations; }
 651   void set_annotations(Annotations* anno)   { _annotations = anno; }
 652   AnnotationArray* class_annotations() const {
 653     if (annotations() == NULL) return NULL;
 654     return annotations()->class_annotations();
 655   }
 656   Array<AnnotationArray*>* fields_annotations() const {
 657     if (annotations() == NULL) return NULL;
 658     return annotations()->fields_annotations();
 659   }
 660 
 661   // allocation
 662   instanceOop allocate_instance(TRAPS);
 663 
 664   // additional member function to return a handle
 665   instanceHandle allocate_instance_handle(TRAPS)      { return instanceHandle(THREAD, allocate_instance(THREAD)); }
 666 
 667   objArrayOop allocate_objArray(int n, int length, TRAPS);
 668   // Helper function
 669   static instanceOop register_finalizer(instanceOop i, TRAPS);
 670 
 671   // Check whether reflection/jni/jvm code is allowed to instantiate this class;
 672   // if not, throw either an Error or an Exception.
 673   virtual void check_valid_for_instantiation(bool throwError, TRAPS);
 674 
 675   // initialization
 676   void call_class_initializer(TRAPS);
 677   void set_initialization_state_and_notify(ClassState state, TRAPS);
 678 
 679   // OopMapCache support
 680   OopMapCache* oop_map_cache()               { return _oop_map_cache; }
 681   void set_oop_map_cache(OopMapCache *cache) { _oop_map_cache = cache; }
 682   void mask_for(methodHandle method, int bci, InterpreterOopMap* entry);
 683 
 684   // JNI identifier support (for static fields - for jni performance)
 685   JNIid* jni_ids()                               { return _jni_ids; }
 686   void set_jni_ids(JNIid* ids)                   { _jni_ids = ids; }
 687   JNIid* jni_id_for(int offset);
 688 
 689   // maintenance of deoptimization dependencies
 690   int mark_dependent_nmethods(DepChange& changes);
 691   void add_dependent_nmethod(nmethod* nm);
 692   void remove_dependent_nmethod(nmethod* nm);
 693 
 694   // On-stack replacement support
 695   nmethod* osr_nmethods_head() const         { return _osr_nmethods_head; };
 696   void set_osr_nmethods_head(nmethod* h)     { _osr_nmethods_head = h; };
 697   void add_osr_nmethod(nmethod* n);
 698   void remove_osr_nmethod(nmethod* n);
 699   nmethod* lookup_osr_nmethod(Method* const m, int bci, int level, bool match_level) const;
 700 
 701   // Breakpoint support (see methods on Method* for details)
 702   BreakpointInfo* breakpoints() const       { return _breakpoints; };
 703   void set_breakpoints(BreakpointInfo* bps) { _breakpoints = bps; };
 704 
 705   // support for stub routines
 706   static ByteSize init_state_offset()  { return in_ByteSize(offset_of(InstanceKlass, _init_state)); }
 707   TRACE_DEFINE_OFFSET;
 708   static ByteSize init_thread_offset() { return in_ByteSize(offset_of(InstanceKlass, _init_thread)); }
 709 
 710   // subclass/subinterface checks
 711   bool implements_interface(Klass* k) const;
 712 
 713   // Access to the implementor of an interface.
 714   Klass* implementor() const
 715   {
 716     Klass** k = adr_implementor();
 717     if (k == NULL) {
 718       return NULL;
 719     } else {
 720       return *k;
 721     }
 722   }
 723 
 724   void set_implementor(Klass* k) {
 725     assert(is_interface(), "not interface");
 726     Klass** addr = adr_implementor();
 727     *addr = k;
 728   }
 729 
 730   int  nof_implementors() const       {
 731     Klass* k = implementor();
 732     if (k == NULL) {
 733       return 0;
 734     } else if (k != this) {
 735       return 1;
 736     } else {
 737       return 2;
 738     }
 739   }
 740 
 741   void add_implementor(Klass* k);  // k is a new class that implements this interface
 742   void init_implementor();           // initialize
 743 
 744   // link this class into the implementors list of every interface it implements
 745   void process_interfaces(Thread *thread);
 746 
 747   // virtual operations from Klass
 748   bool is_leaf_class() const               { return _subklass == NULL; }
 749   GrowableArray<Klass*>* compute_secondary_supers(int num_extra_slots);
 750   bool compute_is_subtype_of(Klass* k);
 751   bool can_be_primary_super_slow() const;
 752   int oop_size(oop obj)  const             { return size_helper(); }
 753   bool oop_is_instance_slow() const        { return true; }
 754 
 755   // Iterators
 756   void do_local_static_fields(FieldClosure* cl);
 757   void do_nonstatic_fields(FieldClosure* cl); // including inherited fields
 758   void do_local_static_fields(void f(fieldDescriptor*, TRAPS), TRAPS);
 759 
 760   void methods_do(void f(Method* method));
 761   void array_klasses_do(void f(Klass* k));
 762   void array_klasses_do(void f(Klass* k, TRAPS), TRAPS);
 763   void with_array_klasses_do(void f(Klass* k));
 764   bool super_types_do(SuperTypeClosure* blk);
 765 
 766   // Casting from Klass*
 767   static InstanceKlass* cast(Klass* k) {
 768     assert(k->is_klass(), "must be");
 769     assert(k->oop_is_instance(), "cast to InstanceKlass");
 770     return (InstanceKlass*) k;
 771   }
 772 
 773   InstanceKlass* java_super() const {
 774     return (super() == NULL) ? NULL : cast(super());
 775   }
 776 
 777   // Sizing (in words)
 778   static int header_size()            { return align_object_offset(sizeof(InstanceKlass)/HeapWordSize); }
 779   static int size(int vtable_length, int itable_length,
 780                   int nonstatic_oop_map_size,
 781                   bool is_interface, bool is_anonymous) {
 782     return align_object_size(header_size() +
 783            align_object_offset(vtable_length) +
 784            align_object_offset(itable_length) +
 785            ((is_interface || is_anonymous) ?
 786              align_object_offset(nonstatic_oop_map_size) :
 787              nonstatic_oop_map_size) +
 788            (is_interface ? (int)sizeof(Klass*)/HeapWordSize : 0) +
 789            (is_anonymous ? (int)sizeof(Klass*)/HeapWordSize : 0));
 790   }
 791   int size() const                    { return size(vtable_length(),
 792                                                itable_length(),
 793                                                nonstatic_oop_map_size(),
 794                                                is_interface(),
 795                                                is_anonymous());
 796   }
 797 
 798   static int vtable_start_offset()    { return header_size(); }
 799   static int vtable_length_offset()   { return offset_of(InstanceKlass, _vtable_len) / HeapWordSize; }
 800 
 801   intptr_t* start_of_vtable() const        { return ((intptr_t*)this) + vtable_start_offset(); }
 802   intptr_t* start_of_itable() const        { return start_of_vtable() + align_object_offset(vtable_length()); }
 803   int  itable_offset_in_words() const { return start_of_itable() - (intptr_t*)this; }
 804 
 805   intptr_t* end_of_itable() const          { return start_of_itable() + itable_length(); }
 806 
 807   address static_field_addr(int offset);
 808 
 809   OopMapBlock* start_of_nonstatic_oop_maps() const {
 810     return (OopMapBlock*)(start_of_itable() + align_object_offset(itable_length()));
 811   }
 812 
 813   Klass** adr_implementor() const {
 814     if (is_interface()) {
 815       return (Klass**)(start_of_nonstatic_oop_maps() +
 816                     nonstatic_oop_map_count());
 817     } else {
 818       return NULL;
 819     }
 820   };
 821 
 822   Klass** adr_host_klass() const {
 823     if (is_anonymous()) {
 824       Klass** adr_impl = adr_implementor();
 825       if (adr_impl != NULL) {
 826         return adr_impl + 1;
 827       } else {
 828         return (Klass**)(start_of_nonstatic_oop_maps() +
 829                       nonstatic_oop_map_count());
 830       }
 831     } else {
 832       return NULL;
 833     }
 834   }
 835 
 836   // Allocation profiling support
 837   juint alloc_size() const            { return _alloc_count * size_helper(); }
 838   void set_alloc_size(juint n)        {}
 839 
 840   // Use this to return the size of an instance in heap words:
 841   int size_helper() const {
 842     return layout_helper_to_size_helper(layout_helper());
 843   }
 844 
 845   // This bit is initialized in classFileParser.cpp.
 846   // It is false under any of the following conditions:
 847   //  - the class is abstract (including any interface)
 848   //  - the class has a finalizer (if !RegisterFinalizersAtInit)
 849   //  - the class size is larger than FastAllocateSizeLimit
 850   //  - the class is java/lang/Class, which cannot be allocated directly
 851   bool can_be_fastpath_allocated() const {
 852     return !layout_helper_needs_slow_path(layout_helper());
 853   }
 854 
 855   // Java vtable/itable
 856   klassVtable* vtable() const;        // return new klassVtable wrapper
 857   inline Method* method_at_vtable(int index);
 858   klassItable* itable() const;        // return new klassItable wrapper
 859   Method* method_at_itable(Klass* holder, int index, TRAPS);
 860 
 861   // Garbage collection
 862   virtual void oops_do(OopClosure* cl);
 863 
 864   void oop_follow_contents(oop obj);
 865   int  oop_adjust_pointers(oop obj);
 866 
 867   void clean_implementors_list(BoolObjectClosure* is_alive);
 868   void clean_method_data(BoolObjectClosure* is_alive);
 869 
 870   // Explicit metaspace deallocation of fields
 871   // For RedefineClasses, we need to deallocate instanceKlasses
 872   void deallocate_contents(ClassLoaderData* loader_data);
 873 
 874   // The constant pool is on stack if any of the methods are executing or
 875   // referenced by handles.
 876   bool on_stack() const { return _constants->on_stack(); }
 877 
 878   void release_C_heap_structures();
 879 
 880   // Parallel Scavenge and Parallel Old
 881   PARALLEL_GC_DECLS
 882 
 883   // Naming
 884   const char* signature_name() const;
 885 
 886   // Iterators
 887   int oop_oop_iterate(oop obj, ExtendedOopClosure* blk) {
 888     return oop_oop_iterate_v(obj, blk);
 889   }
 890 
 891   int oop_oop_iterate_m(oop obj, ExtendedOopClosure* blk, MemRegion mr) {
 892     return oop_oop_iterate_v_m(obj, blk, mr);
 893   }
 894 
 895 #define InstanceKlass_OOP_OOP_ITERATE_DECL(OopClosureType, nv_suffix)      \
 896   int  oop_oop_iterate##nv_suffix(oop obj, OopClosureType* blk);           \
 897   int  oop_oop_iterate##nv_suffix##_m(oop obj, OopClosureType* blk,        \
 898                                       MemRegion mr);
 899 
 900   ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceKlass_OOP_OOP_ITERATE_DECL)
 901   ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceKlass_OOP_OOP_ITERATE_DECL)
 902 
 903 #ifndef SERIALGC
 904 #define InstanceKlass_OOP_OOP_ITERATE_BACKWARDS_DECL(OopClosureType, nv_suffix) \
 905   int  oop_oop_iterate_backwards##nv_suffix(oop obj, OopClosureType* blk);
 906 
 907   ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceKlass_OOP_OOP_ITERATE_BACKWARDS_DECL)
 908   ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceKlass_OOP_OOP_ITERATE_BACKWARDS_DECL)
 909 #endif // !SERIALGC
 910 
 911   u2 idnum_allocated_count() const      { return _idnum_allocated_count; }
 912 private:
 913   // initialization state
 914 #ifdef ASSERT
 915   void set_init_state(ClassState state);
 916 #else
 917   void set_init_state(ClassState state) { _init_state = (u1)state; }
 918 #endif
 919   void set_rewritten()                  { _misc_flags |= _misc_rewritten; }
 920   void set_init_thread(Thread *thread)  { _init_thread = thread; }
 921 
 922   // The RedefineClasses() API can cause new method idnums to be needed
 923   // which will cause the caches to grow. Safety requires different
 924   // cache management logic if the caches can grow instead of just
 925   // going from NULL to non-NULL.
 926   bool idnum_can_increment() const      { return has_been_redefined(); }
 927   jmethodID* methods_jmethod_ids_acquire() const
 928          { return (jmethodID*)OrderAccess::load_ptr_acquire(&_methods_jmethod_ids); }
 929   void release_set_methods_jmethod_ids(jmethodID* jmeths)
 930          { OrderAccess::release_store_ptr(&_methods_jmethod_ids, jmeths); }
 931 
 932   int* methods_cached_itable_indices_acquire() const
 933          { return (int*)OrderAccess::load_ptr_acquire(&_methods_cached_itable_indices); }
 934   void release_set_methods_cached_itable_indices(int* indices)
 935          { OrderAccess::release_store_ptr(&_methods_cached_itable_indices, indices); }
 936 
 937   // Lock during initialization
 938   volatile oop init_lock() const;
 939   void set_init_lock(oop value)      { klass_oop_store(&_init_lock, value); }
 940   void fence_and_clear_init_lock();  // after fully_initialized
 941 
 942   // Offsets for memory management
 943   oop* adr_protection_domain() const { return (oop*)&this->_protection_domain;}
 944   oop* adr_signers() const           { return (oop*)&this->_signers;}
 945   oop* adr_init_lock() const         { return (oop*)&this->_init_lock;}
 946 
 947   // Static methods that are used to implement member methods where an exposed this pointer
 948   // is needed due to possible GCs
 949   static bool link_class_impl                           (instanceKlassHandle this_oop, bool throw_verifyerror, TRAPS);
 950   static bool verify_code                               (instanceKlassHandle this_oop, bool throw_verifyerror, TRAPS);
 951   static void initialize_impl                           (instanceKlassHandle this_oop, TRAPS);
 952   static void eager_initialize_impl                     (instanceKlassHandle this_oop);
 953   static void set_initialization_state_and_notify_impl  (instanceKlassHandle this_oop, ClassState state, TRAPS);
 954   static void call_class_initializer_impl               (instanceKlassHandle this_oop, TRAPS);
 955   static Klass* array_klass_impl                      (instanceKlassHandle this_oop, bool or_null, int n, TRAPS);
 956   static void do_local_static_fields_impl               (instanceKlassHandle this_oop, void f(fieldDescriptor* fd, TRAPS), TRAPS);
 957   /* jni_id_for_impl for jfieldID only */
 958   static JNIid* jni_id_for_impl                         (instanceKlassHandle this_oop, int offset);
 959 
 960   // Returns the array class for the n'th dimension
 961   Klass* array_klass_impl(bool or_null, int n, TRAPS);
 962 
 963   // Returns the array class with this class as element type
 964   Klass* array_klass_impl(bool or_null, TRAPS);
 965 
 966 public:
 967   // CDS support - remove and restore oops from metadata. Oops are not shared.
 968   virtual void remove_unshareable_info();
 969   virtual void restore_unshareable_info(TRAPS);
 970 
 971   // jvm support
 972   jint compute_modifier_flags(TRAPS) const;
 973 
 974 public:
 975   // JVMTI support
 976   jint jvmti_class_status() const;
 977 
 978  public:
 979   // Printing
 980 #ifndef PRODUCT
 981   void print_on(outputStream* st) const;
 982 #endif
 983   void print_value_on(outputStream* st) const;
 984 
 985   void oop_print_value_on(oop obj, outputStream* st);
 986 
 987 #ifndef PRODUCT
 988   void oop_print_on      (oop obj, outputStream* st);
 989 
 990   void print_dependent_nmethods(bool verbose = false);
 991   bool is_dependent_nmethod(nmethod* nm);
 992 #endif
 993 
 994   const char* internal_name() const;
 995 
 996   // Verification
 997   void verify_on(outputStream* st);
 998 
 999   void oop_verify_on(oop obj, outputStream* st);
1000 };
1001 
1002 inline Method* InstanceKlass::method_at_vtable(int index)  {
1003 #ifndef PRODUCT
1004   assert(index >= 0, "valid vtable index");
1005   if (DebugVtables) {
1006     verify_vtable_index(index);
1007   }
1008 #endif
1009   vtableEntry* ve = (vtableEntry*)start_of_vtable();
1010   return ve[index].method();
1011 }
1012 
1013 // for adding methods
1014 // UNSET_IDNUM return means no more ids available
1015 inline u2 InstanceKlass::next_method_idnum() {
1016   if (_idnum_allocated_count == ConstMethod::MAX_IDNUM) {
1017     return ConstMethod::UNSET_IDNUM; // no more ids available
1018   } else {
1019     return _idnum_allocated_count++;
1020   }
1021 }
1022 
1023 
1024 /* JNIid class for jfieldIDs only */
1025 class JNIid: public CHeapObj<mtClass> {
1026   friend class VMStructs;
1027  private:
1028   Klass*             _holder;
1029   JNIid*             _next;
1030   int                _offset;
1031 #ifdef ASSERT
1032   bool               _is_static_field_id;
1033 #endif
1034 
1035  public:
1036   // Accessors
1037   Klass* holder() const           { return _holder; }
1038   int offset() const              { return _offset; }
1039   JNIid* next()                   { return _next; }
1040   // Constructor
1041   JNIid(Klass* holder, int offset, JNIid* next);
1042   // Identifier lookup
1043   JNIid* find(int offset);
1044 
1045   bool find_local_field(fieldDescriptor* fd) {
1046     return InstanceKlass::cast(holder())->find_local_field_from_offset(offset(), true, fd);
1047   }
1048 
1049   static void deallocate(JNIid* id);
1050   // Debugging
1051 #ifdef ASSERT
1052   bool is_static_field_id() const { return _is_static_field_id; }
1053   void set_is_static_field_id()   { _is_static_field_id = true; }
1054 #endif
1055   void verify(Klass* holder);
1056 };
1057 
1058 
1059 // If breakpoints are more numerous than just JVMTI breakpoints,
1060 // consider compressing this data structure.
1061 // It is currently a simple linked list defined in method.hpp.
1062 
1063 class BreakpointInfo;
1064 
1065 
1066 // A collection point for interesting information about the previous
1067 // version(s) of an InstanceKlass. This class uses weak references to
1068 // the information so that the information may be collected as needed
1069 // by the system. If the information is shared, then a regular
1070 // reference must be used because a weak reference would be seen as
1071 // collectible. A GrowableArray of PreviousVersionNodes is attached
1072 // to the InstanceKlass as needed. See PreviousVersionWalker below.
1073 class PreviousVersionNode : public CHeapObj<mtClass> {
1074  private:
1075   // A shared ConstantPool is never collected so we'll always have
1076   // a reference to it so we can update items in the cache. We'll
1077   // have a weak reference to a non-shared ConstantPool until all
1078   // of the methods (EMCP or obsolete) have been collected; the
1079   // non-shared ConstantPool becomes collectible at that point.
1080   ConstantPool*    _prev_constant_pool;  // regular or weak reference
1081   bool    _prev_cp_is_weak;     // true if not a shared ConstantPool
1082 
1083   // If the previous version of the InstanceKlass doesn't have any
1084   // EMCP methods, then _prev_EMCP_methods will be NULL. If all the
1085   // EMCP methods have been collected, then _prev_EMCP_methods can
1086   // have a length of zero.
1087   GrowableArray<Method*>* _prev_EMCP_methods;
1088 
1089 public:
1090   PreviousVersionNode(ConstantPool* prev_constant_pool, bool prev_cp_is_weak,
1091     GrowableArray<Method*>* prev_EMCP_methods);
1092   ~PreviousVersionNode();
1093   ConstantPool* prev_constant_pool() const {
1094     return _prev_constant_pool;
1095   }
1096   GrowableArray<Method*>* prev_EMCP_methods() const {
1097     return _prev_EMCP_methods;
1098   }
1099 };
1100 
1101 
1102 // A Handle-ized version of PreviousVersionNode.
1103 class PreviousVersionInfo : public ResourceObj {
1104  private:
1105   constantPoolHandle   _prev_constant_pool_handle;
1106   // If the previous version of the InstanceKlass doesn't have any
1107   // EMCP methods, then _prev_EMCP_methods will be NULL. Since the
1108   // methods cannot be collected while we hold a handle,
1109   // _prev_EMCP_methods should never have a length of zero.
1110   GrowableArray<methodHandle>* _prev_EMCP_method_handles;
1111 
1112 public:
1113   PreviousVersionInfo(PreviousVersionNode *pv_node);
1114   ~PreviousVersionInfo();
1115   constantPoolHandle prev_constant_pool_handle() const {
1116     return _prev_constant_pool_handle;
1117   }
1118   GrowableArray<methodHandle>* prev_EMCP_method_handles() const {
1119     return _prev_EMCP_method_handles;
1120   }
1121 };
1122 
1123 
1124 // Helper object for walking previous versions. This helper cleans up
1125 // the Handles that it allocates when the helper object is destroyed.
1126 // The PreviousVersionInfo object returned by next_previous_version()
1127 // is only valid until a subsequent call to next_previous_version() or
1128 // the helper object is destroyed.
1129 class PreviousVersionWalker : public StackObj {
1130  private:
1131   GrowableArray<PreviousVersionNode *>* _previous_versions;
1132   int                                   _current_index;
1133   // Fields for cleaning up when we are done walking the previous versions:
1134   // A HandleMark for the PreviousVersionInfo handles:
1135   HandleMark                            _hm;
1136 
1137   // It would be nice to have a ResourceMark field in this helper also,
1138   // but the ResourceMark code says to be careful to delete handles held
1139   // in GrowableArrays _before_ deleting the GrowableArray. Since we
1140   // can't guarantee the order in which the fields are destroyed, we
1141   // have to let the creator of the PreviousVersionWalker object do
1142   // the right thing. Also, adding a ResourceMark here causes an
1143   // include loop.
1144 
1145   // A pointer to the current info object so we can handle the deletes.
1146   PreviousVersionInfo *                 _current_p;
1147 
1148  public:
1149   PreviousVersionWalker(InstanceKlass *ik);
1150   ~PreviousVersionWalker();
1151 
1152   // Return the interesting information for the next previous version
1153   // of the klass. Returns NULL if there are no more previous versions.
1154   PreviousVersionInfo* next_previous_version();
1155 };
1156 
1157 
1158 //
1159 // nmethodBucket is used to record dependent nmethods for
1160 // deoptimization.  nmethod dependencies are actually <klass, method>
1161 // pairs but we really only care about the klass part for purposes of
1162 // finding nmethods which might need to be deoptimized.  Instead of
1163 // recording the method, a count of how many times a particular nmethod
1164 // was recorded is kept.  This ensures that any recording errors are
1165 // noticed since an nmethod should be removed as many times are it's
1166 // added.
1167 //
1168 class nmethodBucket: public CHeapObj<mtClass> {
1169   friend class VMStructs;
1170  private:
1171   nmethod*       _nmethod;
1172   int            _count;
1173   nmethodBucket* _next;
1174 
1175  public:
1176   nmethodBucket(nmethod* nmethod, nmethodBucket* next) {
1177     _nmethod = nmethod;
1178     _next = next;
1179     _count = 1;
1180   }
1181   int count()                             { return _count; }
1182   int increment()                         { _count += 1; return _count; }
1183   int decrement()                         { _count -= 1; assert(_count >= 0, "don't underflow"); return _count; }
1184   nmethodBucket* next()                   { return _next; }
1185   void set_next(nmethodBucket* b)         { _next = b; }
1186   nmethod* get_nmethod()                  { return _nmethod; }
1187 };
1188 
1189 // An iterator that's used to access the inner classes indices in the
1190 // InstanceKlass::_inner_classes array.
1191 class InnerClassesIterator : public StackObj {
1192  private:
1193   Array<jushort>* _inner_classes;
1194   int _length;
1195   int _idx;
1196  public:
1197 
1198   InnerClassesIterator(instanceKlassHandle k) {
1199     _inner_classes = k->inner_classes();
1200     if (k->inner_classes() != NULL) {
1201       _length = _inner_classes->length();
1202       // The inner class array's length should be the multiple of
1203       // inner_class_next_offset if it only contains the InnerClasses
1204       // attribute data, or it should be
1205       // n*inner_class_next_offset+enclosing_method_attribute_size
1206       // if it also contains the EnclosingMethod data.
1207       assert((_length % InstanceKlass::inner_class_next_offset == 0 ||
1208               _length % InstanceKlass::inner_class_next_offset == InstanceKlass::enclosing_method_attribute_size),
1209              "just checking");
1210       // Remove the enclosing_method portion if exists.
1211       if (_length % InstanceKlass::inner_class_next_offset == InstanceKlass::enclosing_method_attribute_size) {
1212         _length -= InstanceKlass::enclosing_method_attribute_size;
1213       }
1214     } else {
1215       _length = 0;
1216     }
1217     _idx = 0;
1218   }
1219 
1220   int length() const {
1221     return _length;
1222   }
1223 
1224   void next() {
1225     _idx += InstanceKlass::inner_class_next_offset;
1226   }
1227 
1228   bool done() const {
1229     return (_idx >= _length);
1230   }
1231 
1232   u2 inner_class_info_index() const {
1233     return _inner_classes->at(
1234                _idx + InstanceKlass::inner_class_inner_class_info_offset);
1235   }
1236 
1237   void set_inner_class_info_index(u2 index) {
1238     _inner_classes->at_put(
1239                _idx + InstanceKlass::inner_class_inner_class_info_offset, index);
1240   }
1241 
1242   u2 outer_class_info_index() const {
1243     return _inner_classes->at(
1244                _idx + InstanceKlass::inner_class_outer_class_info_offset);
1245   }
1246 
1247   void set_outer_class_info_index(u2 index) {
1248     _inner_classes->at_put(
1249                _idx + InstanceKlass::inner_class_outer_class_info_offset, index);
1250   }
1251 
1252   u2 inner_name_index() const {
1253     return _inner_classes->at(
1254                _idx + InstanceKlass::inner_class_inner_name_offset);
1255   }
1256 
1257   void set_inner_name_index(u2 index) {
1258     _inner_classes->at_put(
1259                _idx + InstanceKlass::inner_class_inner_name_offset, index);
1260   }
1261 
1262   u2 inner_access_flags() const {
1263     return _inner_classes->at(
1264                _idx + InstanceKlass::inner_class_access_flags_offset);
1265   }
1266 };
1267 
1268 #endif // SHARE_VM_OOPS_INSTANCEKLASS_HPP