1 /*
   2  * Copyright (c) 1997, 2014, 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/handles.hpp"
  36 #include "runtime/os.hpp"
  37 #include "utilities/accessFlags.hpp"
  38 #include "utilities/bitMap.inline.hpp"
  39 #include "utilities/macros.hpp"
  40 #include "trace/traceMacros.hpp"
  41 
  42 // An InstanceKlass is the VM level representation of a Java class.
  43 // It contains all information needed for at class at execution runtime.
  44 
  45 //  InstanceKlass embedded field layout (after declared fields):
  46 //    [EMBEDDED Java vtable             ] size in words = vtable_len
  47 //    [EMBEDDED nonstatic oop-map blocks] size in words = nonstatic_oop_map_size
  48 //      The embedded nonstatic oop-map blocks are short pairs (offset, length)
  49 //      indicating where oops are located in instances of this klass.
  50 //    [EMBEDDED implementor of the interface] only exist for interface
  51 //    [EMBEDDED host klass        ] only exist for an anonymous class (JSR 292 enabled)
  52 
  53 
  54 // forward declaration for class -- see below for definition
  55 class SuperTypeClosure;
  56 class JNIid;
  57 class jniIdMapBase;
  58 class BreakpointInfo;
  59 class fieldDescriptor;
  60 class DepChange;
  61 class nmethodBucket;
  62 class JvmtiCachedClassFieldMap;
  63 class MemberNameTable;
  64 
  65 // This is used in iterators below.
  66 class FieldClosure: public StackObj {
  67 public:
  68   virtual void do_field(fieldDescriptor* fd) = 0;
  69 };
  70 
  71 #ifndef PRODUCT
  72 // Print fields.
  73 // If "obj" argument to constructor is NULL, prints static fields, otherwise prints non-static fields.
  74 class FieldPrinter: public FieldClosure {
  75    oop _obj;
  76    outputStream* _st;
  77  public:
  78    FieldPrinter(outputStream* st, oop obj = NULL) : _obj(obj), _st(st) {}
  79    void do_field(fieldDescriptor* fd);
  80 };
  81 #endif  // !PRODUCT
  82 
  83 // ValueObjs embedded in klass. Describes where oops are located in instances of
  84 // this klass.
  85 class OopMapBlock VALUE_OBJ_CLASS_SPEC {
  86  public:
  87   // Byte offset of the first oop mapped by this block.
  88   int offset() const          { return _offset; }
  89   void set_offset(int offset) { _offset = offset; }
  90 
  91   // Number of oops in this block.
  92   uint count() const         { return _count; }
  93   void set_count(uint count) { _count = count; }
  94 
  95   // sizeof(OopMapBlock) in HeapWords.
  96   static const int size_in_words() {
  97     return align_size_up(int(sizeof(OopMapBlock)), HeapWordSize) >>
  98       LogHeapWordSize;
  99   }
 100 
 101  private:
 102   int  _offset;
 103   uint _count;
 104 };
 105 
 106 struct JvmtiCachedClassFileData;
 107 
 108 class InstanceKlass: public Klass {
 109   friend class VMStructs;
 110   friend class ClassFileParser;
 111   friend class CompileReplay;
 112 
 113  protected:
 114   // Constructor
 115   InstanceKlass(int vtable_len,
 116                 int itable_len,
 117                 int static_field_size,
 118                 int nonstatic_oop_map_size,
 119                 ReferenceType rt,
 120                 AccessFlags access_flags,
 121                 bool is_anonymous);
 122  public:
 123   static InstanceKlass* allocate_instance_klass(
 124                                           ClassLoaderData* loader_data,
 125                                           int vtable_len,
 126                                           int itable_len,
 127                                           int static_field_size,
 128                                           int nonstatic_oop_map_size,
 129                                           ReferenceType rt,
 130                                           AccessFlags access_flags,
 131                                           Symbol* name,
 132                                           Klass* super_klass,
 133                                           bool is_anonymous,
 134                                           TRAPS);
 135 
 136   InstanceKlass() { assert(DumpSharedSpaces || UseSharedSpaces, "only for CDS"); }
 137 
 138   // See "The Java Virtual Machine Specification" section 2.16.2-5 for a detailed description
 139   // of the class loading & initialization procedure, and the use of the states.
 140   enum ClassState {
 141     allocated,                          // allocated (but not yet linked)
 142     loaded,                             // loaded and inserted in class hierarchy (but not linked yet)
 143     linked,                             // successfully linked/verified (but not initialized yet)
 144     being_initialized,                  // currently running class initializer
 145     fully_initialized,                  // initialized (successfull final state)
 146     initialization_error                // error happened during initialization
 147   };
 148 
 149   static int number_of_instance_classes() { return _total_instanceKlass_count; }
 150 
 151  private:
 152   static volatile int _total_instanceKlass_count;
 153 
 154  protected:
 155   // Annotations for this class
 156   Annotations*    _annotations;
 157   // Array classes holding elements of this class.
 158   Klass*          _array_klasses;
 159   // Constant pool for this class.
 160   ConstantPool* _constants;
 161   // The InnerClasses attribute and EnclosingMethod attribute. The
 162   // _inner_classes is an array of shorts. If the class has InnerClasses
 163   // attribute, then the _inner_classes array begins with 4-tuples of shorts
 164   // [inner_class_info_index, outer_class_info_index,
 165   // inner_name_index, inner_class_access_flags] for the InnerClasses
 166   // attribute. If the EnclosingMethod attribute exists, it occupies the
 167   // last two shorts [class_index, method_index] of the array. If only
 168   // the InnerClasses attribute exists, the _inner_classes array length is
 169   // number_of_inner_classes * 4. If the class has both InnerClasses
 170   // and EnclosingMethod attributes the _inner_classes array length is
 171   // number_of_inner_classes * 4 + enclosing_method_attribute_size.
 172   Array<jushort>* _inner_classes;
 173 
 174   // the source debug extension for this klass, NULL if not specified.
 175   // Specified as UTF-8 string without terminating zero byte in the classfile,
 176   // it is stored in the instanceklass as a NULL-terminated UTF-8 string
 177   char*           _source_debug_extension;
 178   // Array name derived from this class which needs unreferencing
 179   // if this class is unloaded.
 180   Symbol*         _array_name;
 181 
 182   // Number of heapOopSize words used by non-static fields in this klass
 183   // (including inherited fields but after header_size()).
 184   int             _nonstatic_field_size;
 185   int             _static_field_size;    // number words used by static fields (oop and non-oop) in this klass
 186   // Constant pool index to the utf8 entry of the Generic signature,
 187   // or 0 if none.
 188   u2              _generic_signature_index;
 189   // Constant pool index to the utf8 entry for the name of source file
 190   // containing this klass, 0 if not specified.
 191   u2              _source_file_name_index;
 192   u2              _static_oop_field_count;// number of static oop fields in this klass
 193   u2              _java_fields_count;    // The number of declared Java fields
 194   int             _nonstatic_oop_map_size;// size in words of nonstatic oop map blocks
 195 
 196   // _is_marked_dependent can be set concurrently, thus cannot be part of the
 197   // _misc_flags.
 198   bool            _is_marked_dependent;  // used for marking during flushing and deoptimization
 199   bool            _has_unloaded_dependent;
 200 
 201   enum {
 202     _misc_rewritten            = 1 << 0, // methods rewritten.
 203     _misc_has_nonstatic_fields = 1 << 1, // for sizing with UseCompressedOops
 204     _misc_should_verify_class  = 1 << 2, // allow caching of preverification
 205     _misc_is_anonymous         = 1 << 3, // has embedded _host_klass field
 206     _misc_is_contended         = 1 << 4, // marked with contended annotation
 207     _misc_has_default_methods  = 1 << 5, // class/superclass/implemented interfaces has default methods
 208     _misc_has_been_redefined   = 1 << 6  // class has been redefined
 209   };
 210   u2              _misc_flags;
 211   u2              _minor_version;        // minor version number of class file
 212   u2              _major_version;        // major version number of class file
 213   Thread*         _init_thread;          // Pointer to current thread doing initialization (to handle recusive initialization)
 214   int             _vtable_len;           // length of Java vtable (in words)
 215   int             _itable_len;           // length of Java itable (in words)
 216   OopMapCache*    volatile _oop_map_cache;   // OopMapCache for all methods in the klass (allocated lazily)
 217   MemberNameTable* _member_names;        // Member names
 218   JNIid*          _jni_ids;              // First JNI identifier for static fields in this class
 219   jmethodID*      _methods_jmethod_ids;  // jmethodIDs corresponding to method_idnum, or NULL if none
 220   nmethodBucket*  _dependencies;         // list of dependent nmethods
 221   nmethod*        _osr_nmethods_head;    // Head of list of on-stack replacement nmethods for this class
 222   BreakpointInfo* _breakpoints;          // bpt lists, managed by Method*
 223   // Linked instanceKlasses of previous versions
 224   InstanceKlass* _previous_versions;
 225   // JVMTI fields can be moved to their own structure - see 6315920
 226   // JVMTI: cached class file, before retransformable agent modified it in CFLH
 227   JvmtiCachedClassFileData* _cached_class_file;
 228 
 229   volatile u2     _idnum_allocated_count;         // JNI/JVMTI: increments with the addition of methods, old ids don't change
 230 
 231   // Class states are defined as ClassState (see above).
 232   // Place the _init_state here to utilize the unused 2-byte after
 233   // _idnum_allocated_count.
 234   u1              _init_state;                    // state of class
 235   u1              _reference_type;                // reference type
 236 
 237   JvmtiCachedClassFieldMap* _jvmti_cached_class_field_map;  // JVMTI: used during heap iteration
 238 
 239   NOT_PRODUCT(int _verify_count;)  // to avoid redundant verifies
 240 
 241   // Method array.
 242   Array<Method*>* _methods;
 243   // Default Method Array, concrete methods inherited from interfaces
 244   Array<Method*>* _default_methods;
 245   // Interface (Klass*s) this class declares locally to implement.
 246   Array<Klass*>* _local_interfaces;
 247   // Interface (Klass*s) this class implements transitively.
 248   Array<Klass*>* _transitive_interfaces;
 249   // Int array containing the original order of method in the class file (for JVMTI).
 250   Array<int>*     _method_ordering;
 251   // Int array containing the vtable_indices for default_methods
 252   // offset matches _default_methods offset
 253   Array<int>*     _default_vtable_indices;
 254 
 255   // Instance and static variable information, starts with 6-tuples of shorts
 256   // [access, name index, sig index, initval index, low_offset, high_offset]
 257   // for all fields, followed by the generic signature data at the end of
 258   // the array. Only fields with generic signature attributes have the generic
 259   // signature data set in the array. The fields array looks like following:
 260   //
 261   // f1: [access, name index, sig index, initial value index, low_offset, high_offset]
 262   // f2: [access, name index, sig index, initial value index, low_offset, high_offset]
 263   //      ...
 264   // fn: [access, name index, sig index, initial value index, low_offset, high_offset]
 265   //     [generic signature index]
 266   //     [generic signature index]
 267   //     ...
 268   Array<u2>*      _fields;
 269 
 270   // embedded Java vtable follows here
 271   // embedded Java itables follows here
 272   // embedded static fields follows here
 273   // embedded nonstatic oop-map blocks follows here
 274   // embedded implementor of this interface follows here
 275   //   The embedded implementor only exists if the current klass is an
 276   //   iterface. The possible values of the implementor fall into following
 277   //   three cases:
 278   //     NULL: no implementor.
 279   //     A Klass* that's not itself: one implementor.
 280   //     Itself: more than one implementors.
 281   // embedded host klass follows here
 282   //   The embedded host klass only exists in an anonymous class for
 283   //   dynamic language support (JSR 292 enabled). The host class grants
 284   //   its access privileges to this class also. The host class is either
 285   //   named, or a previously loaded anonymous class. A non-anonymous class
 286   //   or an anonymous class loaded through normal classloading does not
 287   //   have this embedded field.
 288   //
 289 
 290   friend class SystemDictionary;
 291 
 292  public:
 293   bool has_nonstatic_fields() const        {
 294     return (_misc_flags & _misc_has_nonstatic_fields) != 0;
 295   }
 296   void set_has_nonstatic_fields(bool b)    {
 297     if (b) {
 298       _misc_flags |= _misc_has_nonstatic_fields;
 299     } else {
 300       _misc_flags &= ~_misc_has_nonstatic_fields;
 301     }
 302   }
 303 
 304   // field sizes
 305   int nonstatic_field_size() const         { return _nonstatic_field_size; }
 306   void set_nonstatic_field_size(int size)  { _nonstatic_field_size = size; }
 307 
 308   int static_field_size() const            { return _static_field_size; }
 309   void set_static_field_size(int size)     { _static_field_size = size; }
 310 
 311   int static_oop_field_count() const       { return (int)_static_oop_field_count; }
 312   void set_static_oop_field_count(u2 size) { _static_oop_field_count = size; }
 313 
 314   // Java vtable
 315   int  vtable_length() const               { return _vtable_len; }
 316   void set_vtable_length(int len)          { _vtable_len = len; }
 317 
 318   // Java itable
 319   int  itable_length() const               { return _itable_len; }
 320   void set_itable_length(int len)          { _itable_len = len; }
 321 
 322   // array klasses
 323   Klass* array_klasses() const             { return _array_klasses; }
 324   void set_array_klasses(Klass* k)         { _array_klasses = k; }
 325 
 326   // methods
 327   Array<Method*>* methods() const          { return _methods; }
 328   void set_methods(Array<Method*>* a)      { _methods = a; }
 329   Method* method_with_idnum(int idnum);
 330 
 331   // method ordering
 332   Array<int>* method_ordering() const     { return _method_ordering; }
 333   void set_method_ordering(Array<int>* m) { _method_ordering = m; }
 334   void copy_method_ordering(intArray* m, TRAPS);
 335 
 336   // default_methods
 337   Array<Method*>* default_methods() const  { return _default_methods; }
 338   void set_default_methods(Array<Method*>* a) { _default_methods = a; }
 339 
 340   // default method vtable_indices
 341   Array<int>* default_vtable_indices() const { return _default_vtable_indices; }
 342   void set_default_vtable_indices(Array<int>* v) { _default_vtable_indices = v; }
 343   Array<int>* create_new_default_vtable_indices(int len, TRAPS);
 344 
 345   // interfaces
 346   Array<Klass*>* local_interfaces() const          { return _local_interfaces; }
 347   void set_local_interfaces(Array<Klass*>* a)      {
 348     guarantee(_local_interfaces == NULL || a == NULL, "Just checking");
 349     _local_interfaces = a; }
 350 
 351   Array<Klass*>* transitive_interfaces() const     { return _transitive_interfaces; }
 352   void set_transitive_interfaces(Array<Klass*>* a) {
 353     guarantee(_transitive_interfaces == NULL || a == NULL, "Just checking");
 354     _transitive_interfaces = a;
 355   }
 356 
 357  private:
 358   friend class fieldDescriptor;
 359   FieldInfo* field(int index) const { return FieldInfo::from_field_array(_fields, index); }
 360 
 361  public:
 362   int     field_offset      (int index) const { return field(index)->offset(); }
 363   int     field_access_flags(int index) const { return field(index)->access_flags(); }
 364   Symbol* field_name        (int index) const { return field(index)->name(constants()); }
 365   Symbol* field_signature   (int index) const { return field(index)->signature(constants()); }
 366 
 367   // Number of Java declared fields
 368   int java_fields_count() const           { return (int)_java_fields_count; }
 369 
 370   Array<u2>* fields() const            { return _fields; }
 371   void set_fields(Array<u2>* f, u2 java_fields_count) {
 372     guarantee(_fields == NULL || f == NULL, "Just checking");
 373     _fields = f;
 374     _java_fields_count = java_fields_count;
 375   }
 376 
 377   // inner classes
 378   Array<u2>* inner_classes() const       { return _inner_classes; }
 379   void set_inner_classes(Array<u2>* f)   { _inner_classes = f; }
 380 
 381   enum InnerClassAttributeOffset {
 382     // From http://mirror.eng/products/jdk/1.1/docs/guide/innerclasses/spec/innerclasses.doc10.html#18814
 383     inner_class_inner_class_info_offset = 0,
 384     inner_class_outer_class_info_offset = 1,
 385     inner_class_inner_name_offset = 2,
 386     inner_class_access_flags_offset = 3,
 387     inner_class_next_offset = 4
 388   };
 389 
 390   enum EnclosingMethodAttributeOffset {
 391     enclosing_method_class_index_offset = 0,
 392     enclosing_method_method_index_offset = 1,
 393     enclosing_method_attribute_size = 2
 394   };
 395 
 396   // method override check
 397   bool is_override(methodHandle super_method, Handle targetclassloader, Symbol* targetclassname, TRAPS);
 398 
 399   // package
 400   bool is_same_class_package(Klass* class2);
 401   bool is_same_class_package(oop classloader2, Symbol* classname2);
 402   static bool is_same_class_package(oop class_loader1, Symbol* class_name1, oop class_loader2, Symbol* class_name2);
 403 
 404   // find an enclosing class (defined where original code was, in jvm.cpp!)
 405   Klass* compute_enclosing_class(bool* inner_is_member, TRAPS) {
 406     instanceKlassHandle self(THREAD, this);
 407     return compute_enclosing_class_impl(self, inner_is_member, THREAD);
 408   }
 409   static Klass* compute_enclosing_class_impl(instanceKlassHandle self,
 410                                                bool* inner_is_member, TRAPS);
 411 
 412   // tell if two classes have the same enclosing class (at package level)
 413   bool is_same_package_member(Klass* class2, TRAPS) {
 414     instanceKlassHandle self(THREAD, this);
 415     return is_same_package_member_impl(self, class2, THREAD);
 416   }
 417   static bool is_same_package_member_impl(instanceKlassHandle self,
 418                                           Klass* class2, TRAPS);
 419 
 420   // initialization state
 421   bool is_loaded() const                   { return _init_state >= loaded; }
 422   bool is_linked() const                   { return _init_state >= linked; }
 423   bool is_initialized() const              { return _init_state == fully_initialized; }
 424   bool is_not_initialized() const          { return _init_state <  being_initialized; }
 425   bool is_being_initialized() const        { return _init_state == being_initialized; }
 426   bool is_in_error_state() const           { return _init_state == initialization_error; }
 427   bool is_reentrant_initialization(Thread *thread)  { return thread == _init_thread; }
 428   ClassState  init_state()                 { return (ClassState)_init_state; }
 429   bool is_rewritten() const                { return (_misc_flags & _misc_rewritten) != 0; }
 430 
 431   // defineClass specified verification
 432   bool should_verify_class() const         {
 433     return (_misc_flags & _misc_should_verify_class) != 0;
 434   }
 435   void set_should_verify_class(bool value) {
 436     if (value) {
 437       _misc_flags |= _misc_should_verify_class;
 438     } else {
 439       _misc_flags &= ~_misc_should_verify_class;
 440     }
 441   }
 442 
 443   // marking
 444   bool is_marked_dependent() const         { return _is_marked_dependent; }
 445   void set_is_marked_dependent(bool value) { _is_marked_dependent = value; }
 446 
 447   bool has_unloaded_dependent() const         { return _has_unloaded_dependent; }
 448   void set_has_unloaded_dependent(bool value) { _has_unloaded_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 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   static Method* find_instance_method(Array<Method*>* methods, Symbol* name, Symbol* signature);
 493 
 494   // find a local method index in default_methods (returns -1 if not found)
 495   static int find_method_index(Array<Method*>* methods, Symbol* name, Symbol* signature, bool skipping_overpass);
 496 
 497   // lookup operation (returns NULL if not found)
 498   Method* uncached_lookup_method(Symbol* name, Symbol* signature, MethodLookupMode mode) const;
 499 
 500   // lookup a method in all the interfaces that this class implements
 501   // (returns NULL if not found)
 502   Method* lookup_method_in_all_interfaces(Symbol* name, Symbol* signature, MethodLookupMode mode) const;
 503 
 504   // lookup a method in local defaults then in all interfaces
 505   // (returns NULL if not found)
 506   Method* lookup_method_in_ordered_interfaces(Symbol* name, Symbol* signature) const;
 507 
 508   // Find method indices by name.  If a method with the specified name is
 509   // found the index to the first method is returned, and 'end' is filled in
 510   // with the index of first non-name-matching method.  If no method is found
 511   // -1 is returned.
 512   int find_method_by_name(Symbol* name, int* end);
 513   static int find_method_by_name(Array<Method*>* methods, Symbol* name, int* end);
 514 
 515   // constant pool
 516   ConstantPool* constants() const        { return _constants; }
 517   void set_constants(ConstantPool* c)    { _constants = c; }
 518 
 519   // protection domain
 520   oop protection_domain() const;
 521 
 522   // signers
 523   objArrayOop signers() const;
 524 
 525   // host class
 526   Klass* host_klass() const              {
 527     Klass** hk = (Klass**)adr_host_klass();
 528     if (hk == NULL) {
 529       return NULL;
 530     } else {
 531       assert(*hk != NULL, "host klass should always be set if the address is not null");
 532       return *hk;
 533     }
 534   }
 535   void set_host_klass(Klass* host)            {
 536     assert(is_anonymous(), "not anonymous");
 537     Klass** addr = (Klass**)adr_host_klass();
 538     assert(addr != NULL, "no reversed space");
 539     if (addr != NULL) {
 540       *addr = host;
 541     }
 542   }
 543   bool is_anonymous() const                {
 544     return (_misc_flags & _misc_is_anonymous) != 0;
 545   }
 546   void set_is_anonymous(bool value)        {
 547     if (value) {
 548       _misc_flags |= _misc_is_anonymous;
 549     } else {
 550       _misc_flags &= ~_misc_is_anonymous;
 551     }
 552   }
 553 
 554   // Oop that keeps the metadata for this class from being unloaded
 555   // in places where the metadata is stored in other places, like nmethods
 556   oop klass_holder() const {
 557     return is_anonymous() ? java_mirror() : class_loader();
 558   }
 559 
 560   bool is_contended() const                {
 561     return (_misc_flags & _misc_is_contended) != 0;
 562   }
 563   void set_is_contended(bool value)        {
 564     if (value) {
 565       _misc_flags |= _misc_is_contended;
 566     } else {
 567       _misc_flags &= ~_misc_is_contended;
 568     }
 569   }
 570 
 571   // source file name
 572   Symbol* source_file_name() const               {
 573     return (_source_file_name_index == 0) ?
 574       (Symbol*)NULL : _constants->symbol_at(_source_file_name_index);
 575   }
 576   u2 source_file_name_index() const              {
 577     return _source_file_name_index;
 578   }
 579   void set_source_file_name_index(u2 sourcefile_index) {
 580     _source_file_name_index = sourcefile_index;
 581   }
 582 
 583   // minor and major version numbers of class file
 584   u2 minor_version() const                 { return _minor_version; }
 585   void set_minor_version(u2 minor_version) { _minor_version = minor_version; }
 586   u2 major_version() const                 { return _major_version; }
 587   void set_major_version(u2 major_version) { _major_version = major_version; }
 588 
 589   // source debug extension
 590   char* source_debug_extension() const     { return _source_debug_extension; }
 591   void set_source_debug_extension(char* array, int length);
 592 
 593   // symbol unloading support (refcount already added)
 594   Symbol* array_name()                     { return _array_name; }
 595   void set_array_name(Symbol* name)        { assert(_array_name == NULL  || name == NULL, "name already created"); _array_name = name; }
 596 
 597   // nonstatic oop-map blocks
 598   static int nonstatic_oop_map_size(unsigned int oop_map_count) {
 599     return oop_map_count * OopMapBlock::size_in_words();
 600   }
 601   unsigned int nonstatic_oop_map_count() const {
 602     return _nonstatic_oop_map_size / OopMapBlock::size_in_words();
 603   }
 604   int nonstatic_oop_map_size() const { return _nonstatic_oop_map_size; }
 605   void set_nonstatic_oop_map_size(int words) {
 606     _nonstatic_oop_map_size = words;
 607   }
 608 
 609   // RedefineClasses() support for previous versions:
 610   void add_previous_version(instanceKlassHandle ikh, int emcp_method_count);
 611 
 612   InstanceKlass* previous_versions() const { return _previous_versions; }
 613 
 614   bool has_been_redefined() const {
 615     return (_misc_flags & _misc_has_been_redefined) != 0;
 616   }
 617   void set_has_been_redefined() {
 618     _misc_flags |= _misc_has_been_redefined;
 619   }
 620 
 621   void init_previous_versions() {
 622     _previous_versions = NULL;
 623   }
 624 
 625   static void purge_previous_versions(InstanceKlass* ik);
 626 
 627   // JVMTI: Support for caching a class file before it is modified by an agent that can do retransformation
 628   void set_cached_class_file(JvmtiCachedClassFileData *data) {
 629     _cached_class_file = data;
 630   }
 631   JvmtiCachedClassFileData * get_cached_class_file() { return _cached_class_file; }
 632   jint get_cached_class_file_len();
 633   unsigned char * get_cached_class_file_bytes();
 634 
 635   // JVMTI: Support for caching of field indices, types, and offsets
 636   void set_jvmti_cached_class_field_map(JvmtiCachedClassFieldMap* descriptor) {
 637     _jvmti_cached_class_field_map = descriptor;
 638   }
 639   JvmtiCachedClassFieldMap* jvmti_cached_class_field_map() const {
 640     return _jvmti_cached_class_field_map;
 641   }
 642 
 643   bool has_default_methods() const {
 644     return (_misc_flags & _misc_has_default_methods) != 0;
 645   }
 646   void set_has_default_methods(bool b) {
 647     if (b) {
 648       _misc_flags |= _misc_has_default_methods;
 649     } else {
 650       _misc_flags &= ~_misc_has_default_methods;
 651     }
 652   }
 653 
 654   // for adding methods, ConstMethod::UNSET_IDNUM means no more ids available
 655   inline u2 next_method_idnum();
 656   void set_initial_method_idnum(u2 value)             { _idnum_allocated_count = value; }
 657 
 658   // generics support
 659   Symbol* generic_signature() const                   {
 660     return (_generic_signature_index == 0) ?
 661       (Symbol*)NULL : _constants->symbol_at(_generic_signature_index);
 662   }
 663   u2 generic_signature_index() const                  {
 664     return _generic_signature_index;
 665   }
 666   void set_generic_signature_index(u2 sig_index)      {
 667     _generic_signature_index = sig_index;
 668   }
 669 
 670   u2 enclosing_method_data(int offset);
 671   u2 enclosing_method_class_index() {
 672     return enclosing_method_data(enclosing_method_class_index_offset);
 673   }
 674   u2 enclosing_method_method_index() {
 675     return enclosing_method_data(enclosing_method_method_index_offset);
 676   }
 677   void set_enclosing_method_indices(u2 class_index,
 678                                     u2 method_index);
 679 
 680   // jmethodID support
 681   static jmethodID get_jmethod_id(instanceKlassHandle ik_h,
 682                      methodHandle method_h);
 683   static jmethodID get_jmethod_id_fetch_or_update(instanceKlassHandle ik_h,
 684                      size_t idnum, jmethodID new_id, jmethodID* new_jmeths,
 685                      jmethodID* to_dealloc_id_p,
 686                      jmethodID** to_dealloc_jmeths_p);
 687   static void get_jmethod_id_length_value(jmethodID* cache, size_t idnum,
 688                 size_t *length_p, jmethodID* id_p);
 689   jmethodID jmethod_id_or_null(Method* method);
 690 
 691   // annotations support
 692   Annotations* annotations() const          { return _annotations; }
 693   void set_annotations(Annotations* anno)   { _annotations = anno; }
 694 
 695   AnnotationArray* class_annotations() const {
 696     return (_annotations != NULL) ? _annotations->class_annotations() : NULL;
 697   }
 698   Array<AnnotationArray*>* fields_annotations() const {
 699     return (_annotations != NULL) ? _annotations->fields_annotations() : NULL;
 700   }
 701   AnnotationArray* class_type_annotations() const {
 702     return (_annotations != NULL) ? _annotations->class_type_annotations() : NULL;
 703   }
 704   Array<AnnotationArray*>* fields_type_annotations() const {
 705     return (_annotations != NULL) ? _annotations->fields_type_annotations() : NULL;
 706   }
 707   // allocation
 708   instanceOop allocate_instance(TRAPS);
 709 
 710   // additional member function to return a handle
 711   instanceHandle allocate_instance_handle(TRAPS)      { return instanceHandle(THREAD, allocate_instance(THREAD)); }
 712 
 713   objArrayOop allocate_objArray(int n, int length, TRAPS);
 714   // Helper function
 715   static instanceOop register_finalizer(instanceOop i, TRAPS);
 716 
 717   // Check whether reflection/jni/jvm code is allowed to instantiate this class;
 718   // if not, throw either an Error or an Exception.
 719   virtual void check_valid_for_instantiation(bool throwError, TRAPS);
 720 
 721   // initialization
 722   void call_class_initializer(TRAPS);
 723   void set_initialization_state_and_notify(ClassState state, TRAPS);
 724 
 725   // OopMapCache support
 726   OopMapCache* oop_map_cache()               { return _oop_map_cache; }
 727   void set_oop_map_cache(OopMapCache *cache) { _oop_map_cache = cache; }
 728   void mask_for(methodHandle method, int bci, InterpreterOopMap* entry);
 729 
 730   // JNI identifier support (for static fields - for jni performance)
 731   JNIid* jni_ids()                               { return _jni_ids; }
 732   void set_jni_ids(JNIid* ids)                   { _jni_ids = ids; }
 733   JNIid* jni_id_for(int offset);
 734 
 735   // maintenance of deoptimization dependencies
 736   int mark_dependent_nmethods(DepChange& changes);
 737   void add_dependent_nmethod(nmethod* nm);
 738   void remove_dependent_nmethod(nmethod* nm);
 739 
 740   // On-stack replacement support
 741   nmethod* osr_nmethods_head() const         { return _osr_nmethods_head; };
 742   void set_osr_nmethods_head(nmethod* h)     { _osr_nmethods_head = h; };
 743   void add_osr_nmethod(nmethod* n);
 744   void remove_osr_nmethod(nmethod* n);
 745   nmethod* lookup_osr_nmethod(const Method* m, int bci, int level, bool match_level, bool skip_marked = false) const;
 746 
 747   // Breakpoint support (see methods on Method* for details)
 748   BreakpointInfo* breakpoints() const       { return _breakpoints; };
 749   void set_breakpoints(BreakpointInfo* bps) { _breakpoints = bps; };
 750 
 751   // support for stub routines
 752   static ByteSize init_state_offset()  { return in_ByteSize(offset_of(InstanceKlass, _init_state)); }
 753   TRACE_DEFINE_OFFSET;
 754   static ByteSize init_thread_offset() { return in_ByteSize(offset_of(InstanceKlass, _init_thread)); }
 755 
 756   // subclass/subinterface checks
 757   bool implements_interface(Klass* k) const;
 758   bool is_same_or_direct_interface(Klass* k) const;
 759 
 760 #ifdef ASSERT
 761   // check whether this class or one of its superclasses was redefined
 762   bool has_redefined_this_or_super() const;
 763 #endif
 764 
 765   // Access to the implementor of an interface.
 766   Klass* implementor() const
 767   {
 768     Klass** k = adr_implementor();
 769     if (k == NULL) {
 770       return NULL;
 771     } else {
 772       return *k;
 773     }
 774   }
 775 
 776   void set_implementor(Klass* k) {
 777     assert(is_interface(), "not interface");
 778     Klass** addr = adr_implementor();
 779     assert(addr != NULL, "null addr");
 780     if (addr != NULL) {
 781       *addr = k;
 782     }
 783   }
 784 
 785   int  nof_implementors() const       {
 786     Klass* k = implementor();
 787     if (k == NULL) {
 788       return 0;
 789     } else if (k != this) {
 790       return 1;
 791     } else {
 792       return 2;
 793     }
 794   }
 795 
 796   void add_implementor(Klass* k);  // k is a new class that implements this interface
 797   void init_implementor();           // initialize
 798 
 799   // link this class into the implementors list of every interface it implements
 800   void process_interfaces(Thread *thread);
 801 
 802   // virtual operations from Klass
 803   bool is_leaf_class() const               { return _subklass == NULL; }
 804   GrowableArray<Klass*>* compute_secondary_supers(int num_extra_slots);
 805   bool compute_is_subtype_of(Klass* k);
 806   bool can_be_primary_super_slow() const;
 807   int oop_size(oop obj)  const             { return size_helper(); }
 808   bool oop_is_instance_slow() const        { return true; }
 809 
 810   // Iterators
 811   void do_local_static_fields(FieldClosure* cl);
 812   void do_nonstatic_fields(FieldClosure* cl); // including inherited fields
 813   void do_local_static_fields(void f(fieldDescriptor*, Handle, TRAPS), Handle, TRAPS);
 814 
 815   void methods_do(void f(Method* method));
 816   void array_klasses_do(void f(Klass* k));
 817   void array_klasses_do(void f(Klass* k, TRAPS), TRAPS);
 818   bool super_types_do(SuperTypeClosure* blk);
 819 
 820   // Casting from Klass*
 821   static InstanceKlass* cast(Klass* k) {
 822     assert(k == NULL || k->is_klass(), "must be");
 823     assert(k == NULL || k->oop_is_instance(), "cast to InstanceKlass");
 824     return (InstanceKlass*) k;
 825   }
 826 
 827   InstanceKlass* java_super() const {
 828     return (super() == NULL) ? NULL : cast(super());
 829   }
 830 
 831   // Sizing (in words)
 832   static int header_size()            { return align_object_offset(sizeof(InstanceKlass)/HeapWordSize); }
 833 
 834   static int size(int vtable_length, int itable_length,
 835                   int nonstatic_oop_map_size,
 836                   bool is_interface, bool is_anonymous) {
 837     return align_object_size(header_size() +
 838            align_object_offset(vtable_length) +
 839            align_object_offset(itable_length) +
 840            ((is_interface || is_anonymous) ?
 841              align_object_offset(nonstatic_oop_map_size) :
 842              nonstatic_oop_map_size) +
 843            (is_interface ? (int)sizeof(Klass*)/HeapWordSize : 0) +
 844            (is_anonymous ? (int)sizeof(Klass*)/HeapWordSize : 0));
 845   }
 846   int size() const                    { return size(vtable_length(),
 847                                                itable_length(),
 848                                                nonstatic_oop_map_size(),
 849                                                is_interface(),
 850                                                is_anonymous());
 851   }
 852 #if INCLUDE_SERVICES
 853   virtual void collect_statistics(KlassSizeStats *sz) const;
 854 #endif
 855 
 856   static int vtable_start_offset()    { return header_size(); }
 857   static int vtable_length_offset()   { return offset_of(InstanceKlass, _vtable_len) / HeapWordSize; }
 858 
 859   intptr_t* start_of_vtable() const        { return ((intptr_t*)this) + vtable_start_offset(); }
 860   intptr_t* start_of_itable() const        { return start_of_vtable() + align_object_offset(vtable_length()); }
 861   int  itable_offset_in_words() const { return start_of_itable() - (intptr_t*)this; }
 862 
 863   intptr_t* end_of_itable() const          { return start_of_itable() + itable_length(); }
 864 
 865   address static_field_addr(int offset);
 866 
 867   OopMapBlock* start_of_nonstatic_oop_maps() const {
 868     return (OopMapBlock*)(start_of_itable() + align_object_offset(itable_length()));
 869   }
 870 
 871   Klass** end_of_nonstatic_oop_maps() const {
 872     return (Klass**)(start_of_nonstatic_oop_maps() +
 873                      nonstatic_oop_map_count());
 874   }
 875 
 876   Klass** adr_implementor() const {
 877     if (is_interface()) {
 878       return (Klass**)end_of_nonstatic_oop_maps();
 879     } else {
 880       return NULL;
 881     }
 882   };
 883 
 884   Klass** adr_host_klass() const {
 885     if (is_anonymous()) {
 886       Klass** adr_impl = adr_implementor();
 887       if (adr_impl != NULL) {
 888         return adr_impl + 1;
 889       } else {
 890         return end_of_nonstatic_oop_maps();
 891       }
 892     } else {
 893       return NULL;
 894     }
 895   }
 896 
 897   // Use this to return the size of an instance in heap words:
 898   int size_helper() const {
 899     return layout_helper_to_size_helper(layout_helper());
 900   }
 901 
 902   // This bit is initialized in classFileParser.cpp.
 903   // It is false under any of the following conditions:
 904   //  - the class is abstract (including any interface)
 905   //  - the class has a finalizer (if !RegisterFinalizersAtInit)
 906   //  - the class size is larger than FastAllocateSizeLimit
 907   //  - the class is java/lang/Class, which cannot be allocated directly
 908   bool can_be_fastpath_allocated() const {
 909     return !layout_helper_needs_slow_path(layout_helper());
 910   }
 911 
 912   // Java vtable/itable
 913   klassVtable* vtable() const;        // return new klassVtable wrapper
 914   inline Method* method_at_vtable(int index);
 915   klassItable* itable() const;        // return new klassItable wrapper
 916   Method* method_at_itable(Klass* holder, int index, TRAPS);
 917 
 918 #if INCLUDE_JVMTI
 919   void adjust_default_methods(Method** old_methods, Method** new_methods,
 920                               int methods_length, bool* trace_name_printed);
 921 #endif // INCLUDE_JVMTI
 922 
 923   // Garbage collection
 924   void oop_follow_contents(oop obj);
 925   int  oop_adjust_pointers(oop obj);
 926 
 927   void clean_implementors_list(BoolObjectClosure* is_alive);
 928   void clean_method_data(BoolObjectClosure* is_alive);
 929   void clean_dependent_nmethods();
 930 
 931   // Explicit metaspace deallocation of fields
 932   // For RedefineClasses and class file parsing errors, we need to deallocate
 933   // instanceKlasses and the metadata they point to.
 934   void deallocate_contents(ClassLoaderData* loader_data);
 935   static void deallocate_methods(ClassLoaderData* loader_data,
 936                                  Array<Method*>* methods);
 937   void static deallocate_interfaces(ClassLoaderData* loader_data,
 938                                     Klass* super_klass,
 939                                     Array<Klass*>* local_interfaces,
 940                                     Array<Klass*>* transitive_interfaces);
 941 
 942   // The constant pool is on stack if any of the methods are executing or
 943   // referenced by handles.
 944   bool on_stack() const { return _constants->on_stack(); }
 945 
 946   // callbacks for actions during class unloading
 947   static void notify_unload_class(InstanceKlass* ik);
 948   static void release_C_heap_structures(InstanceKlass* ik);
 949 
 950   // Parallel Scavenge and Parallel Old
 951   PARALLEL_GC_DECLS
 952 
 953   // Naming
 954   const char* signature_name() const;
 955 
 956   // Iterators
 957   int oop_oop_iterate(oop obj, ExtendedOopClosure* blk) {
 958     return oop_oop_iterate_v(obj, blk);
 959   }
 960 
 961   int oop_oop_iterate_m(oop obj, ExtendedOopClosure* blk, MemRegion mr) {
 962     return oop_oop_iterate_v_m(obj, blk, mr);
 963   }
 964 
 965 #define InstanceKlass_OOP_OOP_ITERATE_DECL(OopClosureType, nv_suffix)      \
 966   int  oop_oop_iterate##nv_suffix(oop obj, OopClosureType* blk);           \
 967   int  oop_oop_iterate##nv_suffix##_m(oop obj, OopClosureType* blk,        \
 968                                       MemRegion mr);
 969 
 970   ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceKlass_OOP_OOP_ITERATE_DECL)
 971   ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceKlass_OOP_OOP_ITERATE_DECL)
 972 
 973 #if INCLUDE_ALL_GCS
 974 #define InstanceKlass_OOP_OOP_ITERATE_BACKWARDS_DECL(OopClosureType, nv_suffix) \
 975   int  oop_oop_iterate_backwards##nv_suffix(oop obj, OopClosureType* blk);
 976 
 977   ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceKlass_OOP_OOP_ITERATE_BACKWARDS_DECL)
 978   ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceKlass_OOP_OOP_ITERATE_BACKWARDS_DECL)
 979 #endif // INCLUDE_ALL_GCS
 980 
 981   u2 idnum_allocated_count() const      { return _idnum_allocated_count; }
 982 
 983 public:
 984   void set_in_error_state() {
 985     assert(DumpSharedSpaces, "only call this when dumping archive");
 986     _init_state = initialization_error;
 987   }
 988   bool check_sharing_error_state();
 989 
 990 private:
 991   // initialization state
 992 #ifdef ASSERT
 993   void set_init_state(ClassState state);
 994 #else
 995   void set_init_state(ClassState state) { _init_state = (u1)state; }
 996 #endif
 997   void set_rewritten()                  { _misc_flags |= _misc_rewritten; }
 998   void set_init_thread(Thread *thread)  { _init_thread = thread; }
 999 
1000   // The RedefineClasses() API can cause new method idnums to be needed
1001   // which will cause the caches to grow. Safety requires different
1002   // cache management logic if the caches can grow instead of just
1003   // going from NULL to non-NULL.
1004   bool idnum_can_increment() const      { return has_been_redefined(); }
1005   jmethodID* methods_jmethod_ids_acquire() const
1006          { return (jmethodID*)OrderAccess::load_ptr_acquire(&_methods_jmethod_ids); }
1007   void release_set_methods_jmethod_ids(jmethodID* jmeths)
1008          { OrderAccess::release_store_ptr(&_methods_jmethod_ids, jmeths); }
1009 
1010   // Lock during initialization
1011 public:
1012   // Lock for (1) initialization; (2) access to the ConstantPool of this class.
1013   // Must be one per class and it has to be a VM internal object so java code
1014   // cannot lock it (like the mirror).
1015   // It has to be an object not a Mutex because it's held through java calls.
1016   oop init_lock() const;
1017 private:
1018   void fence_and_clear_init_lock();
1019 
1020   // Static methods that are used to implement member methods where an exposed this pointer
1021   // is needed due to possible GCs
1022   static bool link_class_impl                           (instanceKlassHandle this_k, bool throw_verifyerror, TRAPS);
1023   static bool verify_code                               (instanceKlassHandle this_k, bool throw_verifyerror, TRAPS);
1024   static void initialize_impl                           (instanceKlassHandle this_k, TRAPS);
1025   static void eager_initialize_impl                     (instanceKlassHandle this_k);
1026   static void set_initialization_state_and_notify_impl  (instanceKlassHandle this_k, ClassState state, TRAPS);
1027   static void call_class_initializer_impl               (instanceKlassHandle this_k, TRAPS);
1028   static Klass* array_klass_impl                        (instanceKlassHandle this_k, bool or_null, int n, TRAPS);
1029   static void do_local_static_fields_impl               (instanceKlassHandle this_k, void f(fieldDescriptor* fd, Handle, TRAPS), Handle, TRAPS);
1030   /* jni_id_for_impl for jfieldID only */
1031   static JNIid* jni_id_for_impl                         (instanceKlassHandle this_k, int offset);
1032 
1033   // Returns the array class for the n'th dimension
1034   Klass* array_klass_impl(bool or_null, int n, TRAPS);
1035 
1036   // Returns the array class with this class as element type
1037   Klass* array_klass_impl(bool or_null, TRAPS);
1038 
1039   // find a local method (returns NULL if not found)
1040   Method* find_method_impl(Symbol* name, Symbol* signature, bool skipping_overpass) const;
1041   static Method* find_method_impl(Array<Method*>* methods, Symbol* name, Symbol* signature, bool skipping_overpass);
1042 
1043   // Free CHeap allocated fields.
1044   void release_C_heap_structures();
1045 
1046   // RedefineClasses support
1047   void link_previous_versions(InstanceKlass* pv) { _previous_versions = pv; }
1048   void mark_newly_obsolete_methods(Array<Method*>* old_methods, int emcp_method_count);
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(ClassLoaderData* loader_data, Handle protection_domain, 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);
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 //
1149 // nmethodBucket is used to record dependent nmethods for
1150 // deoptimization.  nmethod dependencies are actually <klass, method>
1151 // pairs but we really only care about the klass part for purposes of
1152 // finding nmethods which might need to be deoptimized.  Instead of
1153 // recording the method, a count of how many times a particular nmethod
1154 // was recorded is kept.  This ensures that any recording errors are
1155 // noticed since an nmethod should be removed as many times are it's
1156 // added.
1157 //
1158 class nmethodBucket: public CHeapObj<mtClass> {
1159   friend class VMStructs;
1160  private:
1161   nmethod*       _nmethod;
1162   int            _count;
1163   nmethodBucket* _next;
1164 
1165  public:
1166   nmethodBucket(nmethod* nmethod, nmethodBucket* next) {
1167     _nmethod = nmethod;
1168     _next = next;
1169     _count = 1;
1170   }
1171   int count()                             { return _count; }
1172   int increment()                         { _count += 1; return _count; }
1173   int decrement();
1174   nmethodBucket* next()                   { return _next; }
1175   void set_next(nmethodBucket* b)         { _next = b; }
1176   nmethod* get_nmethod()                  { return _nmethod; }
1177 };
1178 
1179 // An iterator that's used to access the inner classes indices in the
1180 // InstanceKlass::_inner_classes array.
1181 class InnerClassesIterator : public StackObj {
1182  private:
1183   Array<jushort>* _inner_classes;
1184   int _length;
1185   int _idx;
1186  public:
1187 
1188   InnerClassesIterator(instanceKlassHandle k) {
1189     _inner_classes = k->inner_classes();
1190     if (k->inner_classes() != NULL) {
1191       _length = _inner_classes->length();
1192       // The inner class array's length should be the multiple of
1193       // inner_class_next_offset if it only contains the InnerClasses
1194       // attribute data, or it should be
1195       // n*inner_class_next_offset+enclosing_method_attribute_size
1196       // if it also contains the EnclosingMethod data.
1197       assert((_length % InstanceKlass::inner_class_next_offset == 0 ||
1198               _length % InstanceKlass::inner_class_next_offset == InstanceKlass::enclosing_method_attribute_size),
1199              "just checking");
1200       // Remove the enclosing_method portion if exists.
1201       if (_length % InstanceKlass::inner_class_next_offset == InstanceKlass::enclosing_method_attribute_size) {
1202         _length -= InstanceKlass::enclosing_method_attribute_size;
1203       }
1204     } else {
1205       _length = 0;
1206     }
1207     _idx = 0;
1208   }
1209 
1210   int length() const {
1211     return _length;
1212   }
1213 
1214   void next() {
1215     _idx += InstanceKlass::inner_class_next_offset;
1216   }
1217 
1218   bool done() const {
1219     return (_idx >= _length);
1220   }
1221 
1222   u2 inner_class_info_index() const {
1223     return _inner_classes->at(
1224                _idx + InstanceKlass::inner_class_inner_class_info_offset);
1225   }
1226 
1227   void set_inner_class_info_index(u2 index) {
1228     _inner_classes->at_put(
1229                _idx + InstanceKlass::inner_class_inner_class_info_offset, index);
1230   }
1231 
1232   u2 outer_class_info_index() const {
1233     return _inner_classes->at(
1234                _idx + InstanceKlass::inner_class_outer_class_info_offset);
1235   }
1236 
1237   void set_outer_class_info_index(u2 index) {
1238     _inner_classes->at_put(
1239                _idx + InstanceKlass::inner_class_outer_class_info_offset, index);
1240   }
1241 
1242   u2 inner_name_index() const {
1243     return _inner_classes->at(
1244                _idx + InstanceKlass::inner_class_inner_name_offset);
1245   }
1246 
1247   void set_inner_name_index(u2 index) {
1248     _inner_classes->at_put(
1249                _idx + InstanceKlass::inner_class_inner_name_offset, index);
1250   }
1251 
1252   u2 inner_access_flags() const {
1253     return _inner_classes->at(
1254                _idx + InstanceKlass::inner_class_access_flags_offset);
1255   }
1256 };
1257 
1258 #endif // SHARE_VM_OOPS_INSTANCEKLASS_HPP