1 /*
   2  * Copyright (c) 1997, 2013, 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 "memory/referenceType.hpp"
  30 #include "oops/annotations.hpp"
  31 #include "oops/constMethod.hpp"
  32 #include "oops/fieldInfo.hpp"
  33 #include "oops/instanceOop.hpp"
  34 #include "oops/klassVtable.hpp"
  35 #include "runtime/atomic.hpp"
  36 #include "runtime/handles.hpp"
  37 #include "runtime/os.hpp"
  38 #include "utilities/accessFlags.hpp"
  39 #include "utilities/bitMap.inline.hpp"
  40 #include "utilities/macros.hpp"
  41 #include "trace/traceMacros.hpp"
  42 
  43 // An InstanceKlass is the VM level representation of a Java class.
  44 // It contains all information needed for at class at execution runtime.
  45 
  46 //  InstanceKlass layout:
  47 //    [C++ vtbl pointer           ] Klass
  48 //    [subtype cache              ] Klass
  49 //    [instance size              ] Klass
  50 //    [java mirror                ] Klass
  51 //    [super                      ] Klass
  52 //    [access_flags               ] Klass
  53 //    [name                       ] Klass
  54 //    [first subklass             ] Klass
  55 //    [next sibling               ] Klass
  56 //    [array klasses              ]
  57 //    [methods                    ]
  58 //    [local interfaces           ]
  59 //    [transitive interfaces      ]
  60 //    [fields                     ]
  61 //    [constants                  ]
  62 //    [class loader               ]
  63 //    [source file name           ]
  64 //    [inner classes              ]
  65 //    [static field size          ]
  66 //    [nonstatic field size       ]
  67 //    [static oop fields size     ]
  68 //    [nonstatic oop maps size    ]
  69 //    [has finalize method        ]
  70 //    [deoptimization mark bit    ]
  71 //    [initialization state       ]
  72 //    [initializing thread        ]
  73 //    [Java vtable length         ]
  74 //    [oop map cache (stack maps) ]
  75 //    [EMBEDDED Java vtable             ] size in words = vtable_len
  76 //    [EMBEDDED nonstatic oop-map blocks] size in words = nonstatic_oop_map_size
  77 //      The embedded nonstatic oop-map blocks are short pairs (offset, length)
  78 //      indicating where oops are located in instances of this klass.
  79 //    [EMBEDDED implementor of the interface] only exist for interface
  80 //    [EMBEDDED host klass        ] only exist for an anonymous class (JSR 292 enabled)
  81 
  82 
  83 // forward declaration for class -- see below for definition
  84 class SuperTypeClosure;
  85 class JNIid;
  86 class jniIdMapBase;
  87 class BreakpointInfo;
  88 class fieldDescriptor;
  89 class DepChange;
  90 class nmethodBucket;
  91 class PreviousVersionNode;
  92 class JvmtiCachedClassFieldMap;
  93 class MemberNameTable;
  94 
  95 // This is used in iterators below.
  96 class FieldClosure: public StackObj {
  97 public:
  98   virtual void do_field(fieldDescriptor* fd) = 0;
  99 };
 100 
 101 #ifndef PRODUCT
 102 // Print fields.
 103 // If "obj" argument to constructor is NULL, prints static fields, otherwise prints non-static fields.
 104 class FieldPrinter: public FieldClosure {
 105    oop _obj;
 106    outputStream* _st;
 107  public:
 108    FieldPrinter(outputStream* st, oop obj = NULL) : _obj(obj), _st(st) {}
 109    void do_field(fieldDescriptor* fd);
 110 };
 111 #endif  // !PRODUCT
 112 
 113 // ValueObjs embedded in klass. Describes where oops are located in instances of
 114 // this klass.
 115 class OopMapBlock VALUE_OBJ_CLASS_SPEC {
 116  public:
 117   // Byte offset of the first oop mapped by this block.
 118   int offset() const          { return _offset; }
 119   void set_offset(int offset) { _offset = offset; }
 120 
 121   // Number of oops in this block.
 122   uint count() const         { return _count; }
 123   void set_count(uint count) { _count = count; }
 124 
 125   // sizeof(OopMapBlock) in HeapWords.
 126   static const int size_in_words() {
 127     return align_size_up(int(sizeof(OopMapBlock)), HeapWordSize) >>
 128       LogHeapWordSize;
 129   }
 130 
 131  private:
 132   int  _offset;
 133   uint _count;
 134 };
 135 
 136 struct JvmtiCachedClassFileData;
 137 
 138 class InstanceKlass: public Klass {
 139   friend class VMStructs;
 140   friend class ClassFileParser;
 141   friend class CompileReplay;
 142 
 143  protected:
 144   // Constructor
 145   InstanceKlass(int vtable_len,
 146                 int itable_len,
 147                 int static_field_size,
 148                 int nonstatic_oop_map_size,
 149                 ReferenceType rt,
 150                 AccessFlags access_flags,
 151                 bool is_anonymous);
 152  public:
 153   static InstanceKlass* allocate_instance_klass(
 154                                           ClassLoaderData* loader_data,
 155                                           int vtable_len,
 156                                           int itable_len,
 157                                           int static_field_size,
 158                                           int nonstatic_oop_map_size,
 159                                           ReferenceType rt,
 160                                           AccessFlags access_flags,
 161                                           Symbol* name,
 162                                           Klass* super_klass,
 163                                           bool is_anonymous,
 164                                           TRAPS);
 165 
 166   InstanceKlass() { assert(DumpSharedSpaces || UseSharedSpaces, "only for CDS"); }
 167 
 168   // See "The Java Virtual Machine Specification" section 2.16.2-5 for a detailed description
 169   // of the class loading & initialization procedure, and the use of the states.
 170   enum ClassState {
 171     allocated,                          // allocated (but not yet linked)
 172     loaded,                             // loaded and inserted in class hierarchy (but not linked yet)
 173     linked,                             // successfully linked/verified (but not initialized yet)
 174     being_initialized,                  // currently running class initializer
 175     fully_initialized,                  // initialized (successfull final state)
 176     initialization_error                // error happened during initialization
 177   };
 178 
 179   static int number_of_instance_classes() { return _total_instanceKlass_count; }
 180 
 181  private:
 182   static volatile int _total_instanceKlass_count;
 183 
 184  protected:
 185   // Annotations for this class
 186   Annotations*    _annotations;
 187   // Array classes holding elements of this class.
 188   Klass*          _array_klasses;
 189   // Constant pool for this class.
 190   ConstantPool* _constants;
 191   // The InnerClasses attribute and EnclosingMethod attribute. The
 192   // _inner_classes is an array of shorts. If the class has InnerClasses
 193   // attribute, then the _inner_classes array begins with 4-tuples of shorts
 194   // [inner_class_info_index, outer_class_info_index,
 195   // inner_name_index, inner_class_access_flags] for the InnerClasses
 196   // attribute. If the EnclosingMethod attribute exists, it occupies the
 197   // last two shorts [class_index, method_index] of the array. If only
 198   // the InnerClasses attribute exists, the _inner_classes array length is
 199   // number_of_inner_classes * 4. If the class has both InnerClasses
 200   // and EnclosingMethod attributes the _inner_classes array length is
 201   // number_of_inner_classes * 4 + enclosing_method_attribute_size.
 202   Array<jushort>* _inner_classes;
 203 
 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   // Array name derived from this class which needs unreferencing
 209   // if this class is unloaded.
 210   Symbol*         _array_name;
 211 
 212   // Number of heapOopSize words used by non-static fields in this klass
 213   // (including inherited fields but after header_size()).
 214   int             _nonstatic_field_size;
 215   int             _static_field_size;    // number words used by static fields (oop and non-oop) in this klass
 216   // Constant pool index to the utf8 entry of the Generic signature,
 217   // or 0 if none.
 218   u2              _generic_signature_index;
 219   // Constant pool index to the utf8 entry for the name of source file
 220   // containing this klass, 0 if not specified.
 221   u2              _source_file_name_index;
 222   u2              _static_oop_field_count;// number of static oop fields in this klass
 223   u2              _java_fields_count;    // The number of declared Java fields
 224   int             _nonstatic_oop_map_size;// size in words of nonstatic oop map blocks
 225 
 226   // _is_marked_dependent can be set concurrently, thus cannot be part of the
 227   // _misc_flags.
 228   bool            _is_marked_dependent;  // used for marking during flushing and deoptimization
 229 
 230   enum {
 231     _misc_rewritten            = 1 << 0, // methods rewritten.
 232     _misc_has_nonstatic_fields = 1 << 1, // for sizing with UseCompressedOops
 233     _misc_should_verify_class  = 1 << 2, // allow caching of preverification
 234     _misc_is_anonymous         = 1 << 3, // has embedded _host_klass field
 235     _misc_is_contended         = 1 << 4, // marked with contended annotation
 236     _misc_has_default_methods  = 1 << 5  // class/superclass/implemented interfaces has default methods
 237   };
 238   u2              _misc_flags;
 239   u2              _minor_version;        // minor version number of class file
 240   u2              _major_version;        // major version number of class file
 241   Thread*         _init_thread;          // Pointer to current thread doing initialization (to handle recusive initialization)
 242   int             _vtable_len;           // length of Java vtable (in words)
 243   int             _itable_len;           // length of Java itable (in words)
 244   OopMapCache*    volatile _oop_map_cache;   // OopMapCache for all methods in the klass (allocated lazily)
 245   MemberNameTable* _member_names;        // Member names
 246   JNIid*          _jni_ids;              // First JNI identifier for static fields in this class
 247   jmethodID*      _methods_jmethod_ids;  // jmethodIDs corresponding to method_idnum, or NULL if none
 248   nmethodBucket*  _dependencies;         // list of dependent nmethods
 249   nmethod*        _osr_nmethods_head;    // Head of list of on-stack replacement nmethods for this class
 250   BreakpointInfo* _breakpoints;          // bpt lists, managed by Method*
 251   // Array of interesting part(s) of the previous version(s) of this
 252   // InstanceKlass. See PreviousVersionWalker below.
 253   GrowableArray<PreviousVersionNode *>* _previous_versions;
 254   // JVMTI fields can be moved to their own structure - see 6315920
 255   // JVMTI: cached class file, before retransformable agent modified it in CFLH
 256   JvmtiCachedClassFileData* _cached_class_file;
 257 
 258   volatile u2     _idnum_allocated_count;         // JNI/JVMTI: increments with the addition of methods, old ids don't change
 259 
 260   // Class states are defined as ClassState (see above).
 261   // Place the _init_state here to utilize the unused 2-byte after
 262   // _idnum_allocated_count.
 263   u1              _init_state;                    // state of class
 264   u1              _reference_type;                // reference type
 265 
 266   JvmtiCachedClassFieldMap* _jvmti_cached_class_field_map;  // JVMTI: used during heap iteration
 267 
 268   NOT_PRODUCT(int _verify_count;)  // to avoid redundant verifies
 269 
 270   // Method array.
 271   Array<Method*>* _methods;
 272   // Default Method Array, concrete methods inherited from interfaces
 273   Array<Method*>* _default_methods;
 274   // Interface (Klass*s) this class declares locally to implement.
 275   Array<Klass*>* _local_interfaces;
 276   // Interface (Klass*s) this class implements transitively.
 277   Array<Klass*>* _transitive_interfaces;
 278   // Int array containing the original order of method in the class file (for JVMTI).
 279   Array<int>*     _method_ordering;
 280   // Int array containing the vtable_indices for default_methods
 281   // offset matches _default_methods offset
 282   Array<int>*     _default_vtable_indices;
 283 
 284   // Instance and static variable information, starts with 6-tuples of shorts
 285   // [access, name index, sig index, initval index, low_offset, high_offset]
 286   // for all fields, followed by the generic signature data at the end of
 287   // the array. Only fields with generic signature attributes have the generic
 288   // signature data set in the array. The fields array looks like following:
 289   //
 290   // f1: [access, name index, sig index, initial value index, low_offset, high_offset]
 291   // f2: [access, name index, sig index, initial value index, low_offset, high_offset]
 292   //      ...
 293   // fn: [access, name index, sig index, initial value index, low_offset, high_offset]
 294   //     [generic signature index]
 295   //     [generic signature index]
 296   //     ...
 297   Array<u2>*      _fields;
 298 
 299   // embedded Java vtable follows here
 300   // embedded Java itables follows here
 301   // embedded static fields follows here
 302   // embedded nonstatic oop-map blocks follows here
 303   // embedded implementor of this interface follows here
 304   //   The embedded implementor only exists if the current klass is an
 305   //   iterface. The possible values of the implementor fall into following
 306   //   three cases:
 307   //     NULL: no implementor.
 308   //     A Klass* that's not itself: one implementor.
 309   //     Itsef: more than one implementors.
 310   // embedded host klass follows here
 311   //   The embedded host klass only exists in an anonymous class for
 312   //   dynamic language support (JSR 292 enabled). The host class grants
 313   //   its access privileges to this class also. The host class is either
 314   //   named, or a previously loaded anonymous class. A non-anonymous class
 315   //   or an anonymous class loaded through normal classloading does not
 316   //   have this embedded field.
 317   //
 318 
 319   friend class SystemDictionary;
 320 
 321  public:
 322   bool has_nonstatic_fields() const        {
 323     return (_misc_flags & _misc_has_nonstatic_fields) != 0;
 324   }
 325   void set_has_nonstatic_fields(bool b)    {
 326     if (b) {
 327       _misc_flags |= _misc_has_nonstatic_fields;
 328     } else {
 329       _misc_flags &= ~_misc_has_nonstatic_fields;
 330     }
 331   }
 332 
 333   // field sizes
 334   int nonstatic_field_size() const         { return _nonstatic_field_size; }
 335   void set_nonstatic_field_size(int size)  { _nonstatic_field_size = size; }
 336 
 337   int static_field_size() const            { return _static_field_size; }
 338   void set_static_field_size(int size)     { _static_field_size = size; }
 339 
 340   int static_oop_field_count() const       { return (int)_static_oop_field_count; }
 341   void set_static_oop_field_count(u2 size) { _static_oop_field_count = size; }
 342 
 343   // Java vtable
 344   int  vtable_length() const               { return _vtable_len; }
 345   void set_vtable_length(int len)          { _vtable_len = len; }
 346 
 347   // Java itable
 348   int  itable_length() const               { return _itable_len; }
 349   void set_itable_length(int len)          { _itable_len = len; }
 350 
 351   // array klasses
 352   Klass* array_klasses() const             { return _array_klasses; }
 353   void set_array_klasses(Klass* k)         { _array_klasses = k; }
 354 
 355   // methods
 356   Array<Method*>* methods() const          { return _methods; }
 357   void set_methods(Array<Method*>* a)      { _methods = a; }
 358   Method* method_with_idnum(int idnum);
 359 
 360   // method ordering
 361   Array<int>* method_ordering() const     { return _method_ordering; }
 362   void set_method_ordering(Array<int>* m) { _method_ordering = m; }
 363   void copy_method_ordering(intArray* m, TRAPS);
 364 
 365   // default_methods
 366   Array<Method*>* default_methods() const  { return _default_methods; }
 367   void set_default_methods(Array<Method*>* a) { _default_methods = a; }
 368 
 369   // default method vtable_indices
 370   Array<int>* default_vtable_indices() const { return _default_vtable_indices; }
 371   void set_default_vtable_indices(Array<int>* v) { _default_vtable_indices = v; }
 372   Array<int>* create_new_default_vtable_indices(int len, TRAPS);
 373 
 374   // interfaces
 375   Array<Klass*>* local_interfaces() const          { return _local_interfaces; }
 376   void set_local_interfaces(Array<Klass*>* a)      {
 377     guarantee(_local_interfaces == NULL || a == NULL, "Just checking");
 378     _local_interfaces = a; }
 379 
 380   Array<Klass*>* transitive_interfaces() const     { return _transitive_interfaces; }
 381   void set_transitive_interfaces(Array<Klass*>* a) {
 382     guarantee(_transitive_interfaces == NULL || a == NULL, "Just checking");
 383     _transitive_interfaces = a;
 384   }
 385 
 386  private:
 387   friend class fieldDescriptor;
 388   FieldInfo* field(int index) const { return FieldInfo::from_field_array(_fields, index); }
 389 
 390  public:
 391   int     field_offset      (int index) const { return field(index)->offset(); }
 392   int     field_access_flags(int index) const { return field(index)->access_flags(); }
 393   Symbol* field_name        (int index) const { return field(index)->name(constants()); }
 394   Symbol* field_signature   (int index) const { return field(index)->signature(constants()); }
 395 
 396   // Number of Java declared fields
 397   int java_fields_count() const           { return (int)_java_fields_count; }
 398 
 399   Array<u2>* fields() const            { return _fields; }
 400   void set_fields(Array<u2>* f, u2 java_fields_count) {
 401     guarantee(_fields == NULL || f == NULL, "Just checking");
 402     _fields = f;
 403     _java_fields_count = java_fields_count;
 404   }
 405 
 406   // inner classes
 407   Array<u2>* inner_classes() const       { return _inner_classes; }
 408   void set_inner_classes(Array<u2>* f)   { _inner_classes = f; }
 409 
 410   enum InnerClassAttributeOffset {
 411     // From http://mirror.eng/products/jdk/1.1/docs/guide/innerclasses/spec/innerclasses.doc10.html#18814
 412     inner_class_inner_class_info_offset = 0,
 413     inner_class_outer_class_info_offset = 1,
 414     inner_class_inner_name_offset = 2,
 415     inner_class_access_flags_offset = 3,
 416     inner_class_next_offset = 4
 417   };
 418 
 419   enum EnclosingMethodAttributeOffset {
 420     enclosing_method_class_index_offset = 0,
 421     enclosing_method_method_index_offset = 1,
 422     enclosing_method_attribute_size = 2
 423   };
 424 
 425   // method override check
 426   bool is_override(methodHandle super_method, Handle targetclassloader, Symbol* targetclassname, TRAPS);
 427 
 428   // package
 429   bool is_same_class_package(Klass* class2);
 430   bool is_same_class_package(oop classloader2, Symbol* classname2);
 431   static bool is_same_class_package(oop class_loader1, Symbol* class_name1, oop class_loader2, Symbol* class_name2);
 432 
 433   // find an enclosing class (defined where original code was, in jvm.cpp!)
 434   Klass* compute_enclosing_class(bool* inner_is_member, TRAPS) {
 435     instanceKlassHandle self(THREAD, this);
 436     return compute_enclosing_class_impl(self, inner_is_member, THREAD);
 437   }
 438   static Klass* compute_enclosing_class_impl(instanceKlassHandle self,
 439                                                bool* inner_is_member, TRAPS);
 440 
 441   // tell if two classes have the same enclosing class (at package level)
 442   bool is_same_package_member(Klass* class2, TRAPS) {
 443     instanceKlassHandle self(THREAD, this);
 444     return is_same_package_member_impl(self, class2, THREAD);
 445   }
 446   static bool is_same_package_member_impl(instanceKlassHandle self,
 447                                           Klass* class2, TRAPS);
 448 
 449   // initialization state
 450   bool is_loaded() const                   { return _init_state >= loaded; }
 451   bool is_linked() const                   { return _init_state >= linked; }
 452   bool is_initialized() const              { return _init_state == fully_initialized; }
 453   bool is_not_initialized() const          { return _init_state <  being_initialized; }
 454   bool is_being_initialized() const        { return _init_state == being_initialized; }
 455   bool is_in_error_state() const           { return _init_state == initialization_error; }
 456   bool is_reentrant_initialization(Thread *thread)  { return thread == _init_thread; }
 457   ClassState  init_state()                 { return (ClassState)_init_state; }
 458   bool is_rewritten() const                { return (_misc_flags & _misc_rewritten) != 0; }
 459 
 460   // defineClass specified verification
 461   bool should_verify_class() const         {
 462     return (_misc_flags & _misc_should_verify_class) != 0;
 463   }
 464   void set_should_verify_class(bool value) {
 465     if (value) {
 466       _misc_flags |= _misc_should_verify_class;
 467     } else {
 468       _misc_flags &= ~_misc_should_verify_class;
 469     }
 470   }
 471 
 472   // marking
 473   bool is_marked_dependent() const         { return _is_marked_dependent; }
 474   void set_is_marked_dependent(bool value) { _is_marked_dependent = value; }
 475 
 476   // initialization (virtuals from Klass)
 477   bool should_be_initialized() const;  // means that initialize should be called
 478   void initialize(TRAPS);
 479   void link_class(TRAPS);
 480   bool link_class_or_fail(TRAPS); // returns false on failure
 481   void unlink_class();
 482   void rewrite_class(TRAPS);
 483   void link_methods(TRAPS);
 484   Method* class_initializer();
 485 
 486   // set the class to initialized if no static initializer is present
 487   void eager_initialize(Thread *thread);
 488 
 489   // reference type
 490   ReferenceType reference_type() const     { return (ReferenceType)_reference_type; }
 491   void set_reference_type(ReferenceType t) {
 492     assert(t == (u1)t, "overflow");
 493     _reference_type = (u1)t;
 494   }
 495 
 496   static ByteSize reference_type_offset() { return in_ByteSize(offset_of(InstanceKlass, _reference_type)); }
 497 
 498   // find local field, returns true if found
 499   bool find_local_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const;
 500   // find field in direct superinterfaces, returns the interface in which the field is defined
 501   Klass* find_interface_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const;
 502   // find field according to JVM spec 5.4.3.2, returns the klass in which the field is defined
 503   Klass* find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const;
 504   // find instance or static fields according to JVM spec 5.4.3.2, returns the klass in which the field is defined
 505   Klass* find_field(Symbol* name, Symbol* sig, bool is_static, fieldDescriptor* fd) const;
 506 
 507   // find a non-static or static field given its offset within the class.
 508   bool contains_field_offset(int offset) {
 509     return instanceOopDesc::contains_field_offset(offset, nonstatic_field_size());
 510   }
 511 
 512   bool find_local_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const;
 513   bool find_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const;
 514 
 515   // find a local method (returns NULL if not found)
 516   Method* find_method(Symbol* name, Symbol* signature) const;
 517   static Method* find_method(Array<Method*>* methods, Symbol* name, Symbol* signature);
 518 
 519   // find a local method index in default_methods (returns -1 if not found)
 520   static int find_method_index(Array<Method*>* methods, Symbol* name, Symbol* signature);
 521 
 522   // lookup operation (returns NULL if not found)
 523   Method* uncached_lookup_method(Symbol* name, Symbol* signature) const;
 524 
 525   // lookup a method in all the interfaces that this class implements
 526   // (returns NULL if not found)
 527   Method* lookup_method_in_all_interfaces(Symbol* name, Symbol* signature) const;
 528   // lookup a method in local defaults then in all interfaces
 529   // (returns NULL if not found)
 530   Method* lookup_method_in_ordered_interfaces(Symbol* name, Symbol* signature) const;
 531 
 532   // Find method indices by name.  If a method with the specified name is
 533   // found the index to the first method is returned, and 'end' is filled in
 534   // with the index of first non-name-matching method.  If no method is found
 535   // -1 is returned.
 536   int find_method_by_name(Symbol* name, int* end);
 537   static int find_method_by_name(Array<Method*>* methods, Symbol* name, int* end);
 538 
 539   // constant pool
 540   ConstantPool* constants() const        { return _constants; }
 541   void set_constants(ConstantPool* c)    { _constants = c; }
 542 
 543   // protection domain
 544   oop protection_domain() const;
 545 
 546   // signers
 547   objArrayOop signers() const;
 548 
 549   // host class
 550   Klass* host_klass() const              {
 551     Klass** hk = (Klass**)adr_host_klass();
 552     if (hk == NULL) {
 553       return NULL;
 554     } else {
 555       return *hk;
 556     }
 557   }
 558   void set_host_klass(Klass* host)            {
 559     assert(is_anonymous(), "not anonymous");
 560     Klass** addr = (Klass**)adr_host_klass();
 561     assert(addr != NULL, "no reversed space");
 562     if (addr != NULL) {
 563       *addr = host;
 564     }
 565   }
 566   bool is_anonymous() const                {
 567     return (_misc_flags & _misc_is_anonymous) != 0;
 568   }
 569   void set_is_anonymous(bool value)        {
 570     if (value) {
 571       _misc_flags |= _misc_is_anonymous;
 572     } else {
 573       _misc_flags &= ~_misc_is_anonymous;
 574     }
 575   }
 576 
 577   // Oop that keeps the metadata for this class from being unloaded
 578   // in places where the metadata is stored in other places, like nmethods
 579   oop klass_holder() const {
 580     return is_anonymous() ? java_mirror() : class_loader();
 581   }
 582 
 583   bool is_contended() const                {
 584     return (_misc_flags & _misc_is_contended) != 0;
 585   }
 586   void set_is_contended(bool value)        {
 587     if (value) {
 588       _misc_flags |= _misc_is_contended;
 589     } else {
 590       _misc_flags &= ~_misc_is_contended;
 591     }
 592   }
 593 
 594   // source file name
 595   Symbol* source_file_name() const               {
 596     return (_source_file_name_index == 0) ?
 597       (Symbol*)NULL : _constants->symbol_at(_source_file_name_index);
 598   }
 599   u2 source_file_name_index() const              {
 600     return _source_file_name_index;
 601   }
 602   void set_source_file_name_index(u2 sourcefile_index) {
 603     _source_file_name_index = sourcefile_index;
 604   }
 605 
 606   // minor and major version numbers of class file
 607   u2 minor_version() const                 { return _minor_version; }
 608   void set_minor_version(u2 minor_version) { _minor_version = minor_version; }
 609   u2 major_version() const                 { return _major_version; }
 610   void set_major_version(u2 major_version) { _major_version = major_version; }
 611 
 612   // source debug extension
 613   char* source_debug_extension() const     { return _source_debug_extension; }
 614   void set_source_debug_extension(char* array, int length);
 615 
 616   // symbol unloading support (refcount already added)
 617   Symbol* array_name()                     { return _array_name; }
 618   void set_array_name(Symbol* name)        { assert(_array_name == NULL  || name == NULL, "name already created"); _array_name = name; }
 619 
 620   // nonstatic oop-map blocks
 621   static int nonstatic_oop_map_size(unsigned int oop_map_count) {
 622     return oop_map_count * OopMapBlock::size_in_words();
 623   }
 624   unsigned int nonstatic_oop_map_count() const {
 625     return _nonstatic_oop_map_size / OopMapBlock::size_in_words();
 626   }
 627   int nonstatic_oop_map_size() const { return _nonstatic_oop_map_size; }
 628   void set_nonstatic_oop_map_size(int words) {
 629     _nonstatic_oop_map_size = words;
 630   }
 631 
 632   // RedefineClasses() support for previous versions:
 633   void add_previous_version(instanceKlassHandle ikh, BitMap *emcp_methods,
 634          int emcp_method_count);
 635   // If the _previous_versions array is non-NULL, then this klass
 636   // has been redefined at least once even if we aren't currently
 637   // tracking a previous version.
 638   bool has_been_redefined() const { return _previous_versions != NULL; }
 639   bool has_previous_version() const;
 640   void init_previous_versions() {
 641     _previous_versions = NULL;
 642   }
 643   GrowableArray<PreviousVersionNode *>* previous_versions() const {
 644     return _previous_versions;
 645   }
 646 
 647   static void purge_previous_versions(InstanceKlass* ik);
 648 
 649   // JVMTI: Support for caching a class file before it is modified by an agent that can do retransformation
 650   void set_cached_class_file(JvmtiCachedClassFileData *data) {
 651     _cached_class_file = data;
 652   }
 653   JvmtiCachedClassFileData * get_cached_class_file() { return _cached_class_file; }
 654   jint get_cached_class_file_len();
 655   unsigned char * get_cached_class_file_bytes();
 656 
 657   // JVMTI: Support for caching of field indices, types, and offsets
 658   void set_jvmti_cached_class_field_map(JvmtiCachedClassFieldMap* descriptor) {
 659     _jvmti_cached_class_field_map = descriptor;
 660   }
 661   JvmtiCachedClassFieldMap* jvmti_cached_class_field_map() const {
 662     return _jvmti_cached_class_field_map;
 663   }
 664 
 665   bool has_default_methods() const {
 666     return (_misc_flags & _misc_has_default_methods) != 0;
 667   }
 668   void set_has_default_methods(bool b) {
 669     if (b) {
 670       _misc_flags |= _misc_has_default_methods;
 671     } else {
 672       _misc_flags &= ~_misc_has_default_methods;
 673     }
 674   }
 675 
 676   // for adding methods, ConstMethod::UNSET_IDNUM means no more ids available
 677   inline u2 next_method_idnum();
 678   void set_initial_method_idnum(u2 value)             { _idnum_allocated_count = value; }
 679 
 680   // generics support
 681   Symbol* generic_signature() const                   {
 682     return (_generic_signature_index == 0) ?
 683       (Symbol*)NULL : _constants->symbol_at(_generic_signature_index);
 684   }
 685   u2 generic_signature_index() const                  {
 686     return _generic_signature_index;
 687   }
 688   void set_generic_signature_index(u2 sig_index)      {
 689     _generic_signature_index = sig_index;
 690   }
 691 
 692   u2 enclosing_method_data(int offset);
 693   u2 enclosing_method_class_index() {
 694     return enclosing_method_data(enclosing_method_class_index_offset);
 695   }
 696   u2 enclosing_method_method_index() {
 697     return enclosing_method_data(enclosing_method_method_index_offset);
 698   }
 699   void set_enclosing_method_indices(u2 class_index,
 700                                     u2 method_index);
 701 
 702   // jmethodID support
 703   static jmethodID get_jmethod_id(instanceKlassHandle ik_h,
 704                      methodHandle method_h);
 705   static jmethodID get_jmethod_id_fetch_or_update(instanceKlassHandle ik_h,
 706                      size_t idnum, jmethodID new_id, jmethodID* new_jmeths,
 707                      jmethodID* to_dealloc_id_p,
 708                      jmethodID** to_dealloc_jmeths_p);
 709   static void get_jmethod_id_length_value(jmethodID* cache, size_t idnum,
 710                 size_t *length_p, jmethodID* id_p);
 711   jmethodID jmethod_id_or_null(Method* method);
 712 
 713   // annotations support
 714   Annotations* annotations() const          { return _annotations; }
 715   void set_annotations(Annotations* anno)   { _annotations = anno; }
 716 
 717   AnnotationArray* class_annotations() const {
 718     return (_annotations != NULL) ? _annotations->class_annotations() : NULL;
 719   }
 720   Array<AnnotationArray*>* fields_annotations() const {
 721     return (_annotations != NULL) ? _annotations->fields_annotations() : NULL;
 722   }
 723   AnnotationArray* class_type_annotations() const {
 724     return (_annotations != NULL) ? _annotations->class_type_annotations() : NULL;
 725   }
 726   Array<AnnotationArray*>* fields_type_annotations() const {
 727     return (_annotations != NULL) ? _annotations->fields_type_annotations() : NULL;
 728   }
 729   // allocation
 730   instanceOop allocate_instance(TRAPS);
 731 
 732   // additional member function to return a handle
 733   instanceHandle allocate_instance_handle(TRAPS)      { return instanceHandle(THREAD, allocate_instance(THREAD)); }
 734 
 735   objArrayOop allocate_objArray(int n, int length, TRAPS);
 736   // Helper function
 737   static instanceOop register_finalizer(instanceOop i, TRAPS);
 738 
 739   // Check whether reflection/jni/jvm code is allowed to instantiate this class;
 740   // if not, throw either an Error or an Exception.
 741   virtual void check_valid_for_instantiation(bool throwError, TRAPS);
 742 
 743   // initialization
 744   void call_class_initializer(TRAPS);
 745   void set_initialization_state_and_notify(ClassState state, TRAPS);
 746 
 747   // OopMapCache support
 748   OopMapCache* oop_map_cache()               { return _oop_map_cache; }
 749   void set_oop_map_cache(OopMapCache *cache) { _oop_map_cache = cache; }
 750   void mask_for(methodHandle method, int bci, InterpreterOopMap* entry);
 751 
 752   // JNI identifier support (for static fields - for jni performance)
 753   JNIid* jni_ids()                               { return _jni_ids; }
 754   void set_jni_ids(JNIid* ids)                   { _jni_ids = ids; }
 755   JNIid* jni_id_for(int offset);
 756 
 757   // maintenance of deoptimization dependencies
 758   int mark_dependent_nmethods(DepChange& changes);
 759   void add_dependent_nmethod(nmethod* nm);
 760   void remove_dependent_nmethod(nmethod* nm);
 761 
 762   // On-stack replacement support
 763   nmethod* osr_nmethods_head() const         { return _osr_nmethods_head; };
 764   void set_osr_nmethods_head(nmethod* h)     { _osr_nmethods_head = h; };
 765   void add_osr_nmethod(nmethod* n);
 766   void remove_osr_nmethod(nmethod* n);
 767   nmethod* lookup_osr_nmethod(const Method* m, int bci, int level, bool match_level) const;
 768 
 769   // Breakpoint support (see methods on Method* for details)
 770   BreakpointInfo* breakpoints() const       { return _breakpoints; };
 771   void set_breakpoints(BreakpointInfo* bps) { _breakpoints = bps; };
 772 
 773   // support for stub routines
 774   static ByteSize init_state_offset()  { return in_ByteSize(offset_of(InstanceKlass, _init_state)); }
 775   TRACE_DEFINE_OFFSET;
 776   static ByteSize init_thread_offset() { return in_ByteSize(offset_of(InstanceKlass, _init_thread)); }
 777 
 778   // subclass/subinterface checks
 779   bool implements_interface(Klass* k) const;
 780 
 781   // Access to the implementor of an interface.
 782   Klass* implementor() const
 783   {
 784     Klass** k = adr_implementor();
 785     if (k == NULL) {
 786       return NULL;
 787     } else {
 788       return *k;
 789     }
 790   }
 791 
 792   void set_implementor(Klass* k) {
 793     assert(is_interface(), "not interface");
 794     Klass** addr = adr_implementor();
 795     assert(addr != NULL, "null addr");
 796     if (addr != NULL) {
 797       *addr = k;
 798     }
 799   }
 800 
 801   int  nof_implementors() const       {
 802     Klass* k = implementor();
 803     if (k == NULL) {
 804       return 0;
 805     } else if (k != this) {
 806       return 1;
 807     } else {
 808       return 2;
 809     }
 810   }
 811 
 812   void add_implementor(Klass* k);  // k is a new class that implements this interface
 813   void init_implementor();           // initialize
 814 
 815   // link this class into the implementors list of every interface it implements
 816   void process_interfaces(Thread *thread);
 817 
 818   // virtual operations from Klass
 819   bool is_leaf_class() const               { return _subklass == NULL; }
 820   GrowableArray<Klass*>* compute_secondary_supers(int num_extra_slots);
 821   bool compute_is_subtype_of(Klass* k);
 822   bool can_be_primary_super_slow() const;
 823   int oop_size(oop obj)  const             { return size_helper(); }
 824   bool oop_is_instance_slow() const        { return true; }
 825 
 826   // Iterators
 827   void do_local_static_fields(FieldClosure* cl);
 828   void do_nonstatic_fields(FieldClosure* cl); // including inherited fields
 829   void do_local_static_fields(void f(fieldDescriptor*, TRAPS), TRAPS);
 830 
 831   void methods_do(void f(Method* method));
 832   void array_klasses_do(void f(Klass* k));
 833   void array_klasses_do(void f(Klass* k, TRAPS), TRAPS);
 834   bool super_types_do(SuperTypeClosure* blk);
 835 
 836   // Casting from Klass*
 837   static InstanceKlass* cast(Klass* k) {
 838     assert(k->is_klass(), "must be");
 839     assert(k->oop_is_instance(), "cast to InstanceKlass");
 840     return (InstanceKlass*) k;
 841   }
 842 
 843   InstanceKlass* java_super() const {
 844     return (super() == NULL) ? NULL : cast(super());
 845   }
 846 
 847   // Sizing (in words)
 848   static int header_size()            { return align_object_offset(sizeof(InstanceKlass)/HeapWordSize); }
 849 
 850   static int size(int vtable_length, int itable_length,
 851                   int nonstatic_oop_map_size,
 852                   bool is_interface, bool is_anonymous) {
 853     return align_object_size(header_size() +
 854            align_object_offset(vtable_length) +
 855            align_object_offset(itable_length) +
 856            ((is_interface || is_anonymous) ?
 857              align_object_offset(nonstatic_oop_map_size) :
 858              nonstatic_oop_map_size) +
 859            (is_interface ? (int)sizeof(Klass*)/HeapWordSize : 0) +
 860            (is_anonymous ? (int)sizeof(Klass*)/HeapWordSize : 0));
 861   }
 862   int size() const                    { return size(vtable_length(),
 863                                                itable_length(),
 864                                                nonstatic_oop_map_size(),
 865                                                is_interface(),
 866                                                is_anonymous());
 867   }
 868 #if INCLUDE_SERVICES
 869   virtual void collect_statistics(KlassSizeStats *sz) const;
 870 #endif
 871 
 872   static int vtable_start_offset()    { return header_size(); }
 873   static int vtable_length_offset()   { return offset_of(InstanceKlass, _vtable_len) / HeapWordSize; }
 874 
 875   intptr_t* start_of_vtable() const        { return ((intptr_t*)this) + vtable_start_offset(); }
 876   intptr_t* start_of_itable() const        { return start_of_vtable() + align_object_offset(vtable_length()); }
 877   int  itable_offset_in_words() const { return start_of_itable() - (intptr_t*)this; }
 878 
 879   intptr_t* end_of_itable() const          { return start_of_itable() + itable_length(); }
 880 
 881   address static_field_addr(int offset);
 882 
 883   OopMapBlock* start_of_nonstatic_oop_maps() const {
 884     return (OopMapBlock*)(start_of_itable() + align_object_offset(itable_length()));
 885   }
 886 
 887   Klass** end_of_nonstatic_oop_maps() const {
 888     return (Klass**)(start_of_nonstatic_oop_maps() +
 889                      nonstatic_oop_map_count());
 890   }
 891 
 892   Klass** adr_implementor() const {
 893     if (is_interface()) {
 894       return (Klass**)end_of_nonstatic_oop_maps();
 895     } else {
 896       return NULL;
 897     }
 898   };
 899 
 900   Klass** adr_host_klass() const {
 901     if (is_anonymous()) {
 902       Klass** adr_impl = adr_implementor();
 903       if (adr_impl != NULL) {
 904         return adr_impl + 1;
 905       } else {
 906         return end_of_nonstatic_oop_maps();
 907       }
 908     } else {
 909       return NULL;
 910     }
 911   }
 912 
 913   // Use this to return the size of an instance in heap words:
 914   int size_helper() const {
 915     return layout_helper_to_size_helper(layout_helper());
 916   }
 917 
 918   // This bit is initialized in classFileParser.cpp.
 919   // It is false under any of the following conditions:
 920   //  - the class is abstract (including any interface)
 921   //  - the class has a finalizer (if !RegisterFinalizersAtInit)
 922   //  - the class size is larger than FastAllocateSizeLimit
 923   //  - the class is java/lang/Class, which cannot be allocated directly
 924   bool can_be_fastpath_allocated() const {
 925     return !layout_helper_needs_slow_path(layout_helper());
 926   }
 927 
 928   // Java vtable/itable
 929   klassVtable* vtable() const;        // return new klassVtable wrapper
 930   inline Method* method_at_vtable(int index);
 931   klassItable* itable() const;        // return new klassItable wrapper
 932   Method* method_at_itable(Klass* holder, int index, TRAPS);
 933 
 934 #if INCLUDE_JVMTI
 935   void adjust_default_methods(Method** old_methods, Method** new_methods,
 936                               int methods_length, bool* trace_name_printed);
 937 #endif // INCLUDE_JVMTI
 938 
 939   // Garbage collection
 940   void oop_follow_contents(oop obj);
 941   int  oop_adjust_pointers(oop obj);
 942 
 943   void clean_implementors_list(BoolObjectClosure* is_alive);
 944   void clean_method_data(BoolObjectClosure* is_alive);
 945 
 946   // Explicit metaspace deallocation of fields
 947   // For RedefineClasses and class file parsing errors, we need to deallocate
 948   // instanceKlasses and the metadata they point to.
 949   void deallocate_contents(ClassLoaderData* loader_data);
 950   static void deallocate_methods(ClassLoaderData* loader_data,
 951                                  Array<Method*>* methods);
 952   void static deallocate_interfaces(ClassLoaderData* loader_data,
 953                                     Klass* super_klass,
 954                                     Array<Klass*>* local_interfaces,
 955                                     Array<Klass*>* transitive_interfaces);
 956 
 957   // The constant pool is on stack if any of the methods are executing or
 958   // referenced by handles.
 959   bool on_stack() const { return _constants->on_stack(); }
 960 
 961   // callbacks for actions during class unloading
 962   static void notify_unload_class(InstanceKlass* ik);
 963   static void release_C_heap_structures(InstanceKlass* ik);
 964 
 965   // Parallel Scavenge and Parallel Old
 966   PARALLEL_GC_DECLS
 967 
 968   // Naming
 969   const char* signature_name() const;
 970 
 971   // Iterators
 972   int oop_oop_iterate(oop obj, ExtendedOopClosure* blk) {
 973     return oop_oop_iterate_v(obj, blk);
 974   }
 975 
 976   int oop_oop_iterate_m(oop obj, ExtendedOopClosure* blk, MemRegion mr) {
 977     return oop_oop_iterate_v_m(obj, blk, mr);
 978   }
 979 
 980 #define InstanceKlass_OOP_OOP_ITERATE_DECL(OopClosureType, nv_suffix)      \
 981   int  oop_oop_iterate##nv_suffix(oop obj, OopClosureType* blk);           \
 982   int  oop_oop_iterate##nv_suffix##_m(oop obj, OopClosureType* blk,        \
 983                                       MemRegion mr);
 984 
 985   ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceKlass_OOP_OOP_ITERATE_DECL)
 986   ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceKlass_OOP_OOP_ITERATE_DECL)
 987 
 988 #if INCLUDE_ALL_GCS
 989 #define InstanceKlass_OOP_OOP_ITERATE_BACKWARDS_DECL(OopClosureType, nv_suffix) \
 990   int  oop_oop_iterate_backwards##nv_suffix(oop obj, OopClosureType* blk);
 991 
 992   ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceKlass_OOP_OOP_ITERATE_BACKWARDS_DECL)
 993   ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceKlass_OOP_OOP_ITERATE_BACKWARDS_DECL)
 994 #endif // INCLUDE_ALL_GCS
 995 
 996   u2 idnum_allocated_count() const      { return _idnum_allocated_count; }
 997 
 998 private:
 999   // initialization state
1000 #ifdef ASSERT
1001   void set_init_state(ClassState state);
1002 #else
1003   void set_init_state(ClassState state) { _init_state = (u1)state; }
1004 #endif
1005   void set_rewritten()                  { _misc_flags |= _misc_rewritten; }
1006   void set_init_thread(Thread *thread)  { _init_thread = thread; }
1007 
1008   // The RedefineClasses() API can cause new method idnums to be needed
1009   // which will cause the caches to grow. Safety requires different
1010   // cache management logic if the caches can grow instead of just
1011   // going from NULL to non-NULL.
1012   bool idnum_can_increment() const      { return has_been_redefined(); }
1013   jmethodID* methods_jmethod_ids_acquire() const
1014          { return (jmethodID*)OrderAccess::load_ptr_acquire(&_methods_jmethod_ids); }
1015   void release_set_methods_jmethod_ids(jmethodID* jmeths)
1016          { OrderAccess::release_store_ptr(&_methods_jmethod_ids, jmeths); }
1017 
1018   // Lock during initialization
1019 public:
1020   // Lock for (1) initialization; (2) access to the ConstantPool of this class.
1021   // Must be one per class and it has to be a VM internal object so java code
1022   // cannot lock it (like the mirror).
1023   // It has to be an object not a Mutex because it's held through java calls.
1024   oop init_lock() const;
1025 private:
1026   void fence_and_clear_init_lock();
1027 
1028   // Static methods that are used to implement member methods where an exposed this pointer
1029   // is needed due to possible GCs
1030   static bool link_class_impl                           (instanceKlassHandle this_oop, bool throw_verifyerror, TRAPS);
1031   static bool verify_code                               (instanceKlassHandle this_oop, bool throw_verifyerror, TRAPS);
1032   static void initialize_impl                           (instanceKlassHandle this_oop, TRAPS);
1033   static void eager_initialize_impl                     (instanceKlassHandle this_oop);
1034   static void set_initialization_state_and_notify_impl  (instanceKlassHandle this_oop, ClassState state, TRAPS);
1035   static void call_class_initializer_impl               (instanceKlassHandle this_oop, TRAPS);
1036   static Klass* array_klass_impl                      (instanceKlassHandle this_oop, bool or_null, int n, TRAPS);
1037   static void do_local_static_fields_impl               (instanceKlassHandle this_oop, void f(fieldDescriptor* fd, TRAPS), TRAPS);
1038   /* jni_id_for_impl for jfieldID only */
1039   static JNIid* jni_id_for_impl                         (instanceKlassHandle this_oop, int offset);
1040 
1041   // Returns the array class for the n'th dimension
1042   Klass* array_klass_impl(bool or_null, int n, TRAPS);
1043 
1044   // Returns the array class with this class as element type
1045   Klass* array_klass_impl(bool or_null, TRAPS);
1046 
1047   // Free CHeap allocated fields.
1048   void release_C_heap_structures();
1049 public:
1050   // CDS support - remove and restore oops from metadata. Oops are not shared.
1051   virtual void remove_unshareable_info();
1052   virtual void restore_unshareable_info(TRAPS);
1053 
1054   // jvm support
1055   jint compute_modifier_flags(TRAPS) const;
1056 
1057   // JSR-292 support
1058   MemberNameTable* member_names() { return _member_names; }
1059   void set_member_names(MemberNameTable* member_names) { _member_names = member_names; }
1060   void add_member_name(int index, Handle member_name);
1061   oop  get_member_name(int index);
1062 
1063 public:
1064   // JVMTI support
1065   jint jvmti_class_status() const;
1066 
1067  public:
1068   // Printing
1069 #ifndef PRODUCT
1070   void print_on(outputStream* st) const;
1071 #endif
1072   void print_value_on(outputStream* st) const;
1073 
1074   void oop_print_value_on(oop obj, outputStream* st);
1075 
1076 #ifndef PRODUCT
1077   void oop_print_on      (oop obj, outputStream* st);
1078 
1079   void print_dependent_nmethods(bool verbose = false);
1080   bool is_dependent_nmethod(nmethod* nm);
1081 #endif
1082 
1083   const char* internal_name() const;
1084 
1085   // Verification
1086   void verify_on(outputStream* st, bool check_dictionary);
1087 
1088   void oop_verify_on(oop obj, outputStream* st);
1089 };
1090 
1091 inline Method* InstanceKlass::method_at_vtable(int index)  {
1092 #ifndef PRODUCT
1093   assert(index >= 0, "valid vtable index");
1094   if (DebugVtables) {
1095     verify_vtable_index(index);
1096   }
1097 #endif
1098   vtableEntry* ve = (vtableEntry*)start_of_vtable();
1099   return ve[index].method();
1100 }
1101 
1102 // for adding methods
1103 // UNSET_IDNUM return means no more ids available
1104 inline u2 InstanceKlass::next_method_idnum() {
1105   if (_idnum_allocated_count == ConstMethod::MAX_IDNUM) {
1106     return ConstMethod::UNSET_IDNUM; // no more ids available
1107   } else {
1108     return _idnum_allocated_count++;
1109   }
1110 }
1111 
1112 
1113 /* JNIid class for jfieldIDs only */
1114 class JNIid: public CHeapObj<mtClass> {
1115   friend class VMStructs;
1116  private:
1117   Klass*             _holder;
1118   JNIid*             _next;
1119   int                _offset;
1120 #ifdef ASSERT
1121   bool               _is_static_field_id;
1122 #endif
1123 
1124  public:
1125   // Accessors
1126   Klass* holder() const           { return _holder; }
1127   int offset() const              { return _offset; }
1128   JNIid* next()                   { return _next; }
1129   // Constructor
1130   JNIid(Klass* holder, int offset, JNIid* next);
1131   // Identifier lookup
1132   JNIid* find(int offset);
1133 
1134   bool find_local_field(fieldDescriptor* fd) {
1135     return InstanceKlass::cast(holder())->find_local_field_from_offset(offset(), true, fd);
1136   }
1137 
1138   static void deallocate(JNIid* id);
1139   // Debugging
1140 #ifdef ASSERT
1141   bool is_static_field_id() const { return _is_static_field_id; }
1142   void set_is_static_field_id()   { _is_static_field_id = true; }
1143 #endif
1144   void verify(Klass* holder);
1145 };
1146 
1147 
1148 // If breakpoints are more numerous than just JVMTI breakpoints,
1149 // consider compressing this data structure.
1150 // It is currently a simple linked list defined in method.hpp.
1151 
1152 class BreakpointInfo;
1153 
1154 
1155 // A collection point for interesting information about the previous
1156 // version(s) of an InstanceKlass.  A GrowableArray of PreviousVersionNodes
1157 // is attached to the InstanceKlass as needed. See PreviousVersionWalker below.
1158 class PreviousVersionNode : public CHeapObj<mtClass> {
1159  private:
1160   ConstantPool*    _prev_constant_pool;
1161 
1162   // If the previous version of the InstanceKlass doesn't have any
1163   // EMCP methods, then _prev_EMCP_methods will be NULL. If all the
1164   // EMCP methods have been collected, then _prev_EMCP_methods can
1165   // have a length of zero.
1166   GrowableArray<Method*>* _prev_EMCP_methods;
1167 
1168 public:
1169   PreviousVersionNode(ConstantPool* prev_constant_pool,
1170                       GrowableArray<Method*>* prev_EMCP_methods);
1171   ~PreviousVersionNode();
1172   ConstantPool* prev_constant_pool() const {
1173     return _prev_constant_pool;
1174   }
1175   GrowableArray<Method*>* prev_EMCP_methods() const {
1176     return _prev_EMCP_methods;
1177   }
1178 };
1179 
1180 
1181 // Helper object for walking previous versions.
1182 class PreviousVersionWalker : public StackObj {
1183  private:
1184   Thread*                               _thread;
1185   GrowableArray<PreviousVersionNode *>* _previous_versions;
1186   int                                   _current_index;
1187 
1188   // A pointer to the current node object so we can handle the deletes.
1189   PreviousVersionNode*                  _current_p;
1190 
1191   // The constant pool handle keeps all the methods in this class from being
1192   // deallocated from the metaspace during class unloading.
1193   constantPoolHandle                    _current_constant_pool_handle;
1194 
1195  public:
1196   PreviousVersionWalker(Thread* thread, InstanceKlass *ik);
1197 
1198   // Return the interesting information for the next previous version
1199   // of the klass. Returns NULL if there are no more previous versions.
1200   PreviousVersionNode* next_previous_version();
1201 };
1202 
1203 
1204 //
1205 // nmethodBucket is used to record dependent nmethods for
1206 // deoptimization.  nmethod dependencies are actually <klass, method>
1207 // pairs but we really only care about the klass part for purposes of
1208 // finding nmethods which might need to be deoptimized.  Instead of
1209 // recording the method, a count of how many times a particular nmethod
1210 // was recorded is kept.  This ensures that any recording errors are
1211 // noticed since an nmethod should be removed as many times are it's
1212 // added.
1213 //
1214 class nmethodBucket: public CHeapObj<mtClass> {
1215   friend class VMStructs;
1216  private:
1217   nmethod*       _nmethod;
1218   int            _count;
1219   nmethodBucket* _next;
1220 
1221  public:
1222   nmethodBucket(nmethod* nmethod, nmethodBucket* next) {
1223     _nmethod = nmethod;
1224     _next = next;
1225     _count = 1;
1226   }
1227   int count()                             { return _count; }
1228   int increment()                         { _count += 1; return _count; }
1229   int decrement()                         { _count -= 1; assert(_count >= 0, "don't underflow"); return _count; }
1230   nmethodBucket* next()                   { return _next; }
1231   void set_next(nmethodBucket* b)         { _next = b; }
1232   nmethod* get_nmethod()                  { return _nmethod; }
1233 };
1234 
1235 // An iterator that's used to access the inner classes indices in the
1236 // InstanceKlass::_inner_classes array.
1237 class InnerClassesIterator : public StackObj {
1238  private:
1239   Array<jushort>* _inner_classes;
1240   int _length;
1241   int _idx;
1242  public:
1243 
1244   InnerClassesIterator(instanceKlassHandle k) {
1245     _inner_classes = k->inner_classes();
1246     if (k->inner_classes() != NULL) {
1247       _length = _inner_classes->length();
1248       // The inner class array's length should be the multiple of
1249       // inner_class_next_offset if it only contains the InnerClasses
1250       // attribute data, or it should be
1251       // n*inner_class_next_offset+enclosing_method_attribute_size
1252       // if it also contains the EnclosingMethod data.
1253       assert((_length % InstanceKlass::inner_class_next_offset == 0 ||
1254               _length % InstanceKlass::inner_class_next_offset == InstanceKlass::enclosing_method_attribute_size),
1255              "just checking");
1256       // Remove the enclosing_method portion if exists.
1257       if (_length % InstanceKlass::inner_class_next_offset == InstanceKlass::enclosing_method_attribute_size) {
1258         _length -= InstanceKlass::enclosing_method_attribute_size;
1259       }
1260     } else {
1261       _length = 0;
1262     }
1263     _idx = 0;
1264   }
1265 
1266   int length() const {
1267     return _length;
1268   }
1269 
1270   void next() {
1271     _idx += InstanceKlass::inner_class_next_offset;
1272   }
1273 
1274   bool done() const {
1275     return (_idx >= _length);
1276   }
1277 
1278   u2 inner_class_info_index() const {
1279     return _inner_classes->at(
1280                _idx + InstanceKlass::inner_class_inner_class_info_offset);
1281   }
1282 
1283   void set_inner_class_info_index(u2 index) {
1284     _inner_classes->at_put(
1285                _idx + InstanceKlass::inner_class_inner_class_info_offset, index);
1286   }
1287 
1288   u2 outer_class_info_index() const {
1289     return _inner_classes->at(
1290                _idx + InstanceKlass::inner_class_outer_class_info_offset);
1291   }
1292 
1293   void set_outer_class_info_index(u2 index) {
1294     _inner_classes->at_put(
1295                _idx + InstanceKlass::inner_class_outer_class_info_offset, index);
1296   }
1297 
1298   u2 inner_name_index() const {
1299     return _inner_classes->at(
1300                _idx + InstanceKlass::inner_class_inner_name_offset);
1301   }
1302 
1303   void set_inner_name_index(u2 index) {
1304     _inner_classes->at_put(
1305                _idx + InstanceKlass::inner_class_inner_name_offset, index);
1306   }
1307 
1308   u2 inner_access_flags() const {
1309     return _inner_classes->at(
1310                _idx + InstanceKlass::inner_class_access_flags_offset);
1311   }
1312 };
1313 
1314 #endif // SHARE_VM_OOPS_INSTANCEKLASS_HPP