1 /*
   2  * Copyright (c) 1997, 2026, 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_OOPS_INSTANCEKLASS_HPP
  26 #define SHARE_OOPS_INSTANCEKLASS_HPP
  27 
  28 #include "memory/allocation.hpp"
  29 #include "memory/referenceType.hpp"
  30 #include "oops/annotations.hpp"
  31 #include "oops/constMethod.hpp"
  32 #include "oops/fieldInfo.hpp"
  33 #include "oops/instanceKlassFlags.hpp"
  34 #include "oops/instanceOop.hpp"
  35 #include "runtime/handles.hpp"
  36 #include "runtime/javaThread.hpp"
  37 #include "utilities/accessFlags.hpp"
  38 #include "utilities/align.hpp"
  39 #include "utilities/growableArray.hpp"
  40 #include "utilities/macros.hpp"
  41 #if INCLUDE_JFR
  42 #include "jfr/support/jfrKlassExtension.hpp"
  43 #endif
  44 
  45 class ConstantPool;
  46 class DeoptimizationScope;
  47 class klassItable;
  48 class RecordComponent;
  49 
  50 // An InstanceKlass is the VM level representation of a Java class.
  51 // It contains all information needed for at class at execution runtime.
  52 
  53 //  InstanceKlass embedded field layout (after declared fields):
  54 //    [EMBEDDED Java vtable             ] size in words = vtable_len
  55 //    [EMBEDDED nonstatic oop-map blocks] size in words = nonstatic_oop_map_size
  56 //      The embedded nonstatic oop-map blocks are short pairs (offset, length)
  57 //      indicating where oops are located in instances of this klass.
  58 //    [EMBEDDED implementor of the interface] only exist for interface
  59 
  60 
  61 // forward declaration for class -- see below for definition
  62 #if INCLUDE_JVMTI
  63 class BreakpointInfo;
  64 #endif
  65 class ClassFileParser;
  66 class ClassFileStream;
  67 class KlassDepChange;
  68 class DependencyContext;
  69 class fieldDescriptor;
  70 class JNIid;
  71 class JvmtiCachedClassFieldMap;
  72 class nmethodBucket;
  73 class OopMapCache;
  74 class InterpreterOopMap;
  75 class PackageEntry;
  76 class ModuleEntry;
  77 
  78 // This is used in iterators below.
  79 class FieldClosure: public StackObj {
  80 public:
  81   virtual void do_field(fieldDescriptor* fd) = 0;
  82 };
  83 
  84 // Print fields.
  85 // If "obj" argument to constructor is null, prints static fields, otherwise prints non-static fields.
  86 class FieldPrinter: public FieldClosure {
  87    oop _obj;
  88    outputStream* _st;
  89  public:
  90    FieldPrinter(outputStream* st, oop obj = nullptr) : _obj(obj), _st(st) {}
  91    void do_field(fieldDescriptor* fd);
  92 };
  93 
  94 // Describes where oops are located in instances of this klass.
  95 class OopMapBlock {
  96  public:
  97   // Byte offset of the first oop mapped by this block.
  98   int offset() const          { return _offset; }
  99   void set_offset(int offset) { _offset = offset; }
 100 
 101   // Number of oops in this block.
 102   uint count() const         { return _count; }
 103   void set_count(uint count) { _count = count; }
 104 
 105   void increment_count(int diff) { _count += diff; }
 106 
 107   int offset_span() const { return _count * heapOopSize; }
 108 
 109   int end_offset() const {
 110     return offset() + offset_span();
 111   }
 112 
 113   bool is_contiguous(int another_offset) const {
 114     return another_offset == end_offset();
 115   }
 116 
 117   // sizeof(OopMapBlock) in words.
 118   static int size_in_words() {
 119     return align_up((int)sizeof(OopMapBlock), wordSize) >>
 120       LogBytesPerWord;
 121   }
 122 
 123   static int compare_offset(const OopMapBlock* a, const OopMapBlock* b) {
 124     return a->offset() - b->offset();
 125   }
 126 
 127  private:
 128   int  _offset;
 129   uint _count;
 130 };
 131 
 132 struct JvmtiCachedClassFileData;
 133 
 134 class InstanceKlass: public Klass {
 135   friend class VMStructs;
 136   friend class ClassFileParser;
 137   friend class CompileReplay;
 138 
 139  public:
 140   static const KlassKind Kind = InstanceKlassKind;
 141 
 142  protected:
 143   InstanceKlass(const ClassFileParser& parser, KlassKind kind = Kind, ReferenceType reference_type = REF_NONE);
 144 
 145  public:
 146   InstanceKlass();
 147 
 148   // See "The Java Virtual Machine Specification" section 2.16.2-5 for a detailed description
 149   // of the class loading & initialization procedure, and the use of the states.
 150   enum ClassState : u1 {
 151     allocated,                          // allocated (but not yet linked)
 152     loaded,                             // loaded and inserted in class hierarchy (but not linked yet)
 153     linked,                             // successfully linked/verified (but not initialized yet)
 154     being_initialized,                  // currently running class initializer
 155     fully_initialized,                  // initialized (successful final state)
 156     initialization_error                // error happened during initialization
 157   };
 158 
 159  private:
 160   static InstanceKlass* allocate_instance_klass(const ClassFileParser& parser, TRAPS);
 161 
 162  protected:
 163   // If you add a new field that points to any metaspace object, you
 164   // must add this field to InstanceKlass::metaspace_pointers_do().
 165 
 166   // Annotations for this class
 167   Annotations*    _annotations;
 168   // Package this class is defined in
 169   PackageEntry*   _package_entry;
 170   // Array classes holding elements of this class.
 171   ObjArrayKlass* volatile _array_klasses;
 172   // Constant pool for this class.
 173   ConstantPool* _constants;
 174   // The InnerClasses attribute and EnclosingMethod attribute. The
 175   // _inner_classes is an array of shorts. If the class has InnerClasses
 176   // attribute, then the _inner_classes array begins with 4-tuples of shorts
 177   // [inner_class_info_index, outer_class_info_index,
 178   // inner_name_index, inner_class_access_flags] for the InnerClasses
 179   // attribute. If the EnclosingMethod attribute exists, it occupies the
 180   // last two shorts [class_index, method_index] of the array. If only
 181   // the InnerClasses attribute exists, the _inner_classes array length is
 182   // number_of_inner_classes * 4. If the class has both InnerClasses
 183   // and EnclosingMethod attributes the _inner_classes array length is
 184   // number_of_inner_classes * 4 + enclosing_method_attribute_size.
 185   Array<jushort>* _inner_classes;
 186 
 187   // The NestMembers attribute. An array of shorts, where each is a
 188   // class info index for the class that is a nest member. This data
 189   // has not been validated.
 190   Array<jushort>* _nest_members;
 191 
 192   // Resolved nest-host klass: either true nest-host or self if we are not
 193   // nested, or an error occurred resolving or validating the nominated
 194   // nest-host. Can also be set directly by JDK API's that establish nest
 195   // relationships.
 196   // By always being set it makes nest-member access checks simpler.
 197   InstanceKlass* _nest_host;
 198 
 199   // The PermittedSubclasses attribute. An array of shorts, where each is a
 200   // class info index for the class that is a permitted subclass.
 201   Array<jushort>* _permitted_subclasses;
 202 
 203   // The contents of the Record attribute.
 204   Array<RecordComponent*>* _record_components;
 205 
 206   // the source debug extension for this klass, null if not specified.
 207   // Specified as UTF-8 string without terminating zero byte in the classfile,
 208   // it is stored in the instanceklass as a null-terminated UTF-8 string
 209   const char*     _source_debug_extension;
 210 
 211   // Number of heapOopSize words used by non-static fields in this klass
 212   // (including inherited fields but after header_size()).
 213   int             _nonstatic_field_size;
 214   int             _static_field_size;       // number words used by static fields (oop and non-oop) in this klass
 215   int             _nonstatic_oop_map_size;  // size in words of nonstatic oop map blocks
 216   int             _itable_len;              // length of Java itable (in words)
 217 
 218   // The NestHost attribute. The class info index for the class
 219   // that is the nest-host of this class. This data has not been validated.
 220   u2              _nest_host_index;
 221   u2              _this_class_index;        // constant pool entry
 222   u2              _static_oop_field_count;  // number of static oop fields in this klass
 223 
 224   volatile u2     _idnum_allocated_count;   // JNI/JVMTI: increments with the addition of methods, old ids don't change
 225 
 226   // Class states are defined as ClassState (see above).
 227   // Place the _init_state here to utilize the unused 2-byte after
 228   // _idnum_allocated_count.
 229   volatile ClassState _init_state;          // state of class
 230 
 231   u1                 _reference_type;                // reference type
 232 
 233   AccessFlags        _access_flags;    // Access flags. The class/interface distinction is stored here.
 234 
 235   // State is set either at parse time or while executing, atomically to not disturb other state
 236   InstanceKlassFlags _misc_flags;
 237 
 238   JavaThread* volatile _init_thread;        // Pointer to current thread doing initialization (to handle recursive initialization)
 239 
 240   OopMapCache*    volatile _oop_map_cache;   // OopMapCache for all methods in the klass (allocated lazily)
 241   JNIid*          _jni_ids;                  // First JNI identifier for static fields in this class
 242   jmethodID* volatile _methods_jmethod_ids;  // jmethodIDs corresponding to method_idnum, or null if none
 243   nmethodBucket*  volatile _dep_context;     // packed DependencyContext structure
 244   uint64_t        volatile _dep_context_last_cleaned;
 245   nmethod*        _osr_nmethods_head;    // Head of list of on-stack replacement nmethods for this class
 246 #if INCLUDE_JVMTI
 247   BreakpointInfo* _breakpoints;          // bpt lists, managed by Method*
 248   // Linked instanceKlasses of previous versions
 249   InstanceKlass* _previous_versions;
 250   // JVMTI fields can be moved to their own structure - see 6315920
 251   // JVMTI: cached class file, before retransformable agent modified it in CFLH
 252   JvmtiCachedClassFileData* _cached_class_file;
 253 #endif
 254 
 255 #if INCLUDE_JVMTI
 256   JvmtiCachedClassFieldMap* _jvmti_cached_class_field_map;  // JVMTI: used during heap iteration
 257 #endif
 258 
 259   NOT_PRODUCT(int _verify_count;)  // to avoid redundant verifies
 260   NOT_PRODUCT(volatile int _shared_class_load_count;) // ensure a shared class is loaded only once
 261 
 262   // Method array.
 263   Array<Method*>* _methods;
 264   // Default Method Array, concrete methods inherited from interfaces
 265   Array<Method*>* _default_methods;
 266   // Interfaces (InstanceKlass*s) this class declares locally to implement.
 267   Array<InstanceKlass*>* _local_interfaces;
 268   // Interfaces (InstanceKlass*s) this class implements transitively.
 269   Array<InstanceKlass*>* _transitive_interfaces;
 270   // Int array containing the original order of method in the class file (for JVMTI).
 271   Array<int>*     _method_ordering;
 272   // Int array containing the vtable_indices for default_methods
 273   // offset matches _default_methods offset
 274   Array<int>*     _default_vtable_indices;
 275 
 276   // Fields information is stored in an UNSIGNED5 encoded stream (see fieldInfo.hpp)
 277   Array<u1>*          _fieldinfo_stream;
 278   Array<u1>*          _fieldinfo_search_table;
 279   Array<FieldStatus>* _fields_status;
 280 
 281   // embedded Java vtable follows here
 282   // embedded Java itables follows here
 283   // embedded static fields follows here
 284   // embedded nonstatic oop-map blocks follows here
 285   // embedded implementor of this interface follows here
 286   //   The embedded implementor only exists if the current klass is an
 287   //   interface. The possible values of the implementor fall into following
 288   //   three cases:
 289   //     null: no implementor.
 290   //     A Klass* that's not itself: one implementor.
 291   //     Itself: more than one implementors.
 292   //
 293 
 294   friend class SystemDictionary;
 295 
 296   static bool _disable_method_binary_search;
 297 
 298   // Controls finalizer registration
 299   static bool _finalization_enabled;
 300 
 301  public:
 302 
 303   // Queries finalization state
 304   static bool is_finalization_enabled() { return _finalization_enabled; }
 305 
 306   // Sets finalization state
 307   static void set_finalization_enabled(bool val) { _finalization_enabled = val; }
 308 
 309   // Access flags
 310   AccessFlags access_flags() const         { return _access_flags;  }
 311   void set_access_flags(AccessFlags flags) { _access_flags = flags; }
 312 
 313   bool is_public() const                { return _access_flags.is_public(); }
 314   bool is_final() const                 { return _access_flags.is_final(); }
 315   bool is_interface() const override    { return _access_flags.is_interface(); }
 316   bool is_abstract() const override     { return _access_flags.is_abstract(); }
 317   bool is_super() const                 { return _access_flags.is_super(); }
 318   bool is_synthetic() const             { return _access_flags.is_synthetic(); }
 319   void set_is_synthetic()               { _access_flags.set_is_synthetic(); }
 320 
 321   static ByteSize access_flags_offset() { return byte_offset_of(InstanceKlass, _access_flags); }
 322 
 323   void set_is_cloneable();
 324 
 325   // Quick checks for the loader that defined this class (without switching on this->class_loader())
 326   bool defined_by_boot_loader() const      { return _misc_flags.defined_by_boot_loader(); }
 327   bool defined_by_platform_loader() const  { return _misc_flags.defined_by_platform_loader(); }
 328   bool defined_by_app_loader() const       { return _misc_flags.defined_by_app_loader(); }
 329   bool defined_by_other_loaders() const    { return _misc_flags.defined_by_other_loaders(); }
 330   void set_class_loader_type()             { _misc_flags.set_class_loader_type(_class_loader_data); }
 331 
 332   bool shared_loading_failed() const { return _misc_flags.shared_loading_failed(); }
 333 
 334   void set_shared_loading_failed() { _misc_flags.set_shared_loading_failed(true); }
 335 
 336   bool has_nonstatic_fields() const        { return _misc_flags.has_nonstatic_fields(); }
 337   void set_has_nonstatic_fields(bool b)    { _misc_flags.set_has_nonstatic_fields(b); }
 338 
 339   bool has_localvariable_table() const     { return _misc_flags.has_localvariable_table(); }
 340   void set_has_localvariable_table(bool b) { _misc_flags.set_has_localvariable_table(b); }
 341 
 342   // field sizes
 343   int nonstatic_field_size() const         { return _nonstatic_field_size; }
 344   void set_nonstatic_field_size(int size)  { _nonstatic_field_size = size; }
 345 
 346   int static_field_size() const            { return _static_field_size; }
 347   void set_static_field_size(int size)     { _static_field_size = size; }
 348 
 349   int static_oop_field_count() const       { return (int)_static_oop_field_count; }
 350   void set_static_oop_field_count(u2 size) { _static_oop_field_count = size; }
 351 
 352   bool trust_final_fields()                { return _misc_flags.trust_final_fields(); }
 353   void set_trust_final_fields(bool value)  { _misc_flags.set_trust_final_fields(value); }
 354 
 355   // Java itable
 356   int  itable_length() const               { return _itable_len; }
 357   void set_itable_length(int len)          { _itable_len = len; }
 358 
 359   // array klasses
 360   ObjArrayKlass* array_klasses() const     { return _array_klasses; }
 361   inline ObjArrayKlass* array_klasses_acquire() const; // load with acquire semantics
 362   inline void release_set_array_klasses(ObjArrayKlass* k); // store with release semantics
 363   void set_array_klasses(ObjArrayKlass* k) { _array_klasses = k; }
 364 
 365   // methods
 366   Array<Method*>* methods() const          { return _methods; }
 367   void set_methods(Array<Method*>* a)      { _methods = a; }
 368   Method* method_with_idnum(int idnum) const;
 369   Method* method_with_orig_idnum(int idnum) const;
 370   Method* method_with_orig_idnum(int idnum, int version) const;
 371 
 372   // method ordering
 373   Array<int>* method_ordering() const     { return _method_ordering; }
 374   void set_method_ordering(Array<int>* m) { _method_ordering = m; }
 375   void copy_method_ordering(const intArray* m, TRAPS);
 376 
 377   // default_methods
 378   Array<Method*>* default_methods() const  { return _default_methods; }
 379   void set_default_methods(Array<Method*>* a) { _default_methods = a; }
 380 
 381   // default method vtable_indices
 382   Array<int>* default_vtable_indices() const { return _default_vtable_indices; }
 383   void set_default_vtable_indices(Array<int>* v) { _default_vtable_indices = v; }
 384   Array<int>* create_new_default_vtable_indices(int len, TRAPS);
 385 
 386   // interfaces
 387   Array<InstanceKlass*>* local_interfaces() const          { return _local_interfaces; }
 388   void set_local_interfaces(Array<InstanceKlass*>* a)      {
 389     guarantee(_local_interfaces == nullptr || a == nullptr, "Just checking");
 390     _local_interfaces = a; }
 391 
 392   Array<InstanceKlass*>* transitive_interfaces() const     { return _transitive_interfaces; }
 393   void set_transitive_interfaces(Array<InstanceKlass*>* a) {
 394     guarantee(_transitive_interfaces == nullptr || a == nullptr, "Just checking");
 395     _transitive_interfaces = a;
 396   }
 397 
 398  private:
 399   friend class fieldDescriptor;
 400   FieldInfo field(int index) const;
 401 
 402  public:
 403   int     field_offset      (int index) const { return field(index).offset(); }
 404   int     field_access_flags(int index) const { return field(index).access_flags().as_field_flags(); }
 405   FieldInfo::FieldFlags field_flags(int index) const { return field(index).field_flags(); }
 406   FieldStatus field_status(int index)   const { return fields_status()->at(index); }
 407   inline Symbol* field_name        (int index) const;
 408   inline Symbol* field_signature   (int index) const;
 409 
 410   // Number of Java declared fields
 411   int java_fields_count() const;
 412   int total_fields_count() const;
 413 
 414   Array<u1>* fieldinfo_stream() const { return _fieldinfo_stream; }
 415   void set_fieldinfo_stream(Array<u1>* fis) { _fieldinfo_stream = fis; }
 416 
 417   Array<u1>* fieldinfo_search_table() const { return _fieldinfo_search_table; }
 418   void set_fieldinfo_search_table(Array<u1>* table) { _fieldinfo_search_table = table; }
 419 
 420   Array<FieldStatus>* fields_status() const {return _fields_status; }
 421   void set_fields_status(Array<FieldStatus>* array) { _fields_status = array; }
 422 
 423   // inner classes
 424   Array<u2>* inner_classes() const       { return _inner_classes; }
 425   void set_inner_classes(Array<u2>* f)   { _inner_classes = f; }
 426 
 427   // nest members
 428   Array<u2>* nest_members() const     { return _nest_members; }
 429   void set_nest_members(Array<u2>* m) { _nest_members = m; }
 430 
 431   // nest-host index
 432   jushort nest_host_index() const { return _nest_host_index; }
 433   void set_nest_host_index(u2 i)  { _nest_host_index = i; }
 434   // dynamic nest member support
 435   void set_nest_host(InstanceKlass* host);
 436 
 437   // record components
 438   Array<RecordComponent*>* record_components() const { return _record_components; }
 439   void set_record_components(Array<RecordComponent*>* record_components) {
 440     _record_components = record_components;
 441   }
 442   bool is_record() const;
 443 
 444   // test for enum class (or possibly an anonymous subclass within a sealed enum)
 445   bool is_enum_subclass() const;
 446 
 447   // permitted subclasses
 448   Array<u2>* permitted_subclasses() const     { return _permitted_subclasses; }
 449   void set_permitted_subclasses(Array<u2>* s) { _permitted_subclasses = s; }
 450 
 451 private:
 452   // Called to verify that k is a member of this nest - does not look at k's nest-host,
 453   // nor does it resolve any CP entries or load any classes.
 454   bool has_nest_member(JavaThread* current, InstanceKlass* k) const;
 455 
 456 public:
 457   // Call this only if you know that the nest host has been initialized.
 458   InstanceKlass* nest_host_not_null() {
 459     assert(_nest_host != nullptr, "must be");
 460     return _nest_host;
 461   }
 462   InstanceKlass* nest_host_or_null() {
 463     return _nest_host;
 464   }
 465   // Used to construct informative IllegalAccessError messages at a higher level,
 466   // if there was an issue resolving or validating the nest host.
 467   // Returns null if there was no error.
 468   const char* nest_host_error();
 469   // Returns nest-host class, resolving and validating it if needed.
 470   // Returns null if resolution is not possible from the calling context.
 471   InstanceKlass* nest_host(TRAPS);
 472   // Check if this klass is a nestmate of k - resolves this nest-host and k's
 473   bool has_nestmate_access_to(InstanceKlass* k, TRAPS);
 474 
 475   // Called to verify that k is a permitted subclass of this class.
 476   // The incoming stringStream is used for logging, and for the caller to create
 477   // a detailed exception message on failure.
 478   bool has_as_permitted_subclass(const InstanceKlass* k, stringStream& ss) const;
 479 
 480   enum InnerClassAttributeOffset {
 481     // From http://mirror.eng/products/jdk/1.1/docs/guide/innerclasses/spec/innerclasses.doc10.html#18814
 482     inner_class_inner_class_info_offset = 0,
 483     inner_class_outer_class_info_offset = 1,
 484     inner_class_inner_name_offset = 2,
 485     inner_class_access_flags_offset = 3,
 486     inner_class_next_offset = 4
 487   };
 488 
 489   enum EnclosingMethodAttributeOffset {
 490     enclosing_method_class_index_offset = 0,
 491     enclosing_method_method_index_offset = 1,
 492     enclosing_method_attribute_size = 2
 493   };
 494 
 495   // package
 496   PackageEntry* package() const override { return _package_entry; }
 497   ModuleEntry* module() const override;
 498   bool in_javabase_module() const;
 499   bool in_unnamed_package() const   { return (_package_entry == nullptr); }
 500   void set_package(ClassLoaderData* loader_data, PackageEntry* pkg_entry, TRAPS);
 501   // If the package for the InstanceKlass is in the boot loader's package entry
 502   // table then sets the classpath_index field so that
 503   // get_system_package() will know to return a non-null value for the
 504   // package's location.  And, so that the package will be added to the list of
 505   // packages returned by get_system_packages().
 506   // For packages whose classes are loaded from the boot loader class path, the
 507   // classpath_index indicates which entry on the boot loader class path.
 508   void set_classpath_index(s2 path_index);
 509   bool is_same_class_package(const Klass* class2) const;
 510   bool is_same_class_package(oop other_class_loader, const Symbol* other_class_name) const;
 511 
 512   // find an enclosing class
 513   InstanceKlass* compute_enclosing_class(bool* inner_is_member, TRAPS) const;
 514 
 515   // Find InnerClasses attribute and return outer_class_info_index & inner_name_index.
 516   bool find_inner_classes_attr(int* ooff, int* noff, TRAPS) const;
 517 
 518  private:
 519   // Check prohibited package ("java/" only loadable by boot or platform loaders)
 520   static void check_prohibited_package(Symbol* class_name,
 521                                        ClassLoaderData* loader_data,
 522                                        TRAPS);
 523 
 524   JavaThread* init_thread()  { return AtomicAccess::load(&_init_thread); }
 525   const char* init_thread_name() {
 526     return init_thread()->name_raw();
 527   }
 528 
 529  public:
 530   // initialization state
 531   bool is_loaded() const                   { return init_state() >= loaded; }
 532   bool is_linked() const                   { return init_state() >= linked; }
 533   bool is_initialized() const              { return init_state() == fully_initialized; }
 534   bool is_not_initialized() const          { return init_state() <  being_initialized; }
 535   bool is_being_initialized() const        { return init_state() == being_initialized; }
 536   bool is_in_error_state() const           { return init_state() == initialization_error; }
 537   bool is_reentrant_initialization(Thread *thread)  { return thread == _init_thread; }
 538   ClassState  init_state() const           { return AtomicAccess::load_acquire(&_init_state); }
 539   const char* init_state_name() const;
 540   bool is_rewritten() const                { return _misc_flags.rewritten(); }
 541 
 542   // is this a sealed class
 543   bool is_sealed() const;
 544 
 545   // defineClass specified verification
 546   bool should_verify_class() const         { return _misc_flags.should_verify_class(); }
 547   void set_should_verify_class(bool value) { _misc_flags.set_should_verify_class(value); }
 548 
 549   // marking
 550   bool is_marked_dependent() const         { return _misc_flags.is_marked_dependent(); }
 551   void set_is_marked_dependent(bool value) { _misc_flags.set_is_marked_dependent(value); }
 552 
 553   // initialization (virtuals from Klass)
 554   bool should_be_initialized() const override;  // means that initialize should be called
 555   void initialize_with_aot_initialized_mirror(bool early_init, TRAPS);
 556   void assert_no_clinit_will_run_for_aot_initialized_class() const NOT_DEBUG_RETURN;
 557   void initialize(TRAPS) override;
 558   void initialize_preemptable(TRAPS) override;
 559   void link_class(TRAPS);
 560   bool link_class_or_fail(TRAPS); // returns false on failure
 561   void rewrite_class(TRAPS);
 562   void link_methods(TRAPS);
 563   Method* class_initializer() const;
 564   bool interface_needs_clinit_execution_as_super(bool also_check_supers=true) const;
 565 
 566   // reference type
 567   ReferenceType reference_type() const     { return (ReferenceType)_reference_type; }
 568 
 569   // this class cp index
 570   u2 this_class_index() const             { return _this_class_index; }
 571   void set_this_class_index(u2 index)     { _this_class_index = index; }
 572 
 573   static ByteSize reference_type_offset() { return byte_offset_of(InstanceKlass, _reference_type); }
 574 
 575   // find local field, returns true if found
 576   bool find_local_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const;
 577   // find field in direct superinterfaces, returns the interface in which the field is defined
 578   Klass* find_interface_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const;
 579   // find field according to JVM spec 5.4.3.2, returns the klass in which the field is defined
 580   Klass* find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const override;
 581   // find instance or static fields according to JVM spec 5.4.3.2, returns the klass in which the field is defined
 582   Klass* find_field(Symbol* name, Symbol* sig, bool is_static, fieldDescriptor* fd) const;
 583 
 584   // find a non-static or static field given its offset within the class.
 585   bool contains_field_offset(int offset);
 586 
 587   bool find_local_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const;
 588   bool find_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const;
 589 
 590  private:
 591   inline static int quick_search(const Array<Method*>* methods, const Symbol* name);
 592 
 593  public:
 594   static void disable_method_binary_search() {
 595     _disable_method_binary_search = true;
 596   }
 597 
 598   // find a local method (returns null if not found)
 599   Method* find_method(const Symbol* name, const Symbol* signature) const;
 600   static Method* find_method(const Array<Method*>* methods,
 601                              const Symbol* name,
 602                              const Symbol* signature);
 603 
 604   // find a local method, but skip static methods
 605   Method* find_instance_method(const Symbol* name, const Symbol* signature,
 606                                PrivateLookupMode private_mode) const;
 607   static Method* find_instance_method(const Array<Method*>* methods,
 608                                       const Symbol* name,
 609                                       const Symbol* signature,
 610                                       PrivateLookupMode private_mode);
 611 
 612   // find a local method (returns null if not found)
 613   Method* find_local_method(const Symbol* name,
 614                             const Symbol* signature,
 615                             OverpassLookupMode overpass_mode,
 616                             StaticLookupMode static_mode,
 617                             PrivateLookupMode private_mode) const;
 618 
 619   // find a local method from given methods array (returns null if not found)
 620   static Method* find_local_method(const Array<Method*>* methods,
 621                                    const Symbol* name,
 622                                    const Symbol* signature,
 623                                    OverpassLookupMode overpass_mode,
 624                                    StaticLookupMode static_mode,
 625                                    PrivateLookupMode private_mode);
 626 
 627   // find a local method index in methods or default_methods (returns -1 if not found)
 628   static int find_method_index(const Array<Method*>* methods,
 629                                const Symbol* name,
 630                                const Symbol* signature,
 631                                OverpassLookupMode overpass_mode,
 632                                StaticLookupMode static_mode,
 633                                PrivateLookupMode private_mode);
 634 
 635   // lookup operation (returns null if not found)
 636   Method* uncached_lookup_method(const Symbol* name,
 637                                  const Symbol* signature,
 638                                  OverpassLookupMode overpass_mode,
 639                                  PrivateLookupMode private_mode = PrivateLookupMode::find) const override;
 640 
 641   // lookup a method in all the interfaces that this class implements
 642   // (returns null if not found)
 643   Method* lookup_method_in_all_interfaces(Symbol* name, Symbol* signature, DefaultsLookupMode defaults_mode) const;
 644 
 645   // lookup a method in local defaults then in all interfaces
 646   // (returns null if not found)
 647   Method* lookup_method_in_ordered_interfaces(Symbol* name, Symbol* signature) const;
 648 
 649   // Find method indices by name.  If a method with the specified name is
 650   // found the index to the first method is returned, and 'end' is filled in
 651   // with the index of first non-name-matching method.  If no method is found
 652   // -1 is returned.
 653   int find_method_by_name(const Symbol* name, int* end) const;
 654   static int find_method_by_name(const Array<Method*>* methods,
 655                                  const Symbol* name, int* end);
 656 
 657   // constant pool
 658   ConstantPool* constants() const        { return _constants; }
 659   void set_constants(ConstantPool* c)    { _constants = c; }
 660 
 661   // protection domain
 662   oop protection_domain() const override;
 663 
 664   // signers
 665   objArrayOop signers() const;
 666 
 667   bool is_contended() const                { return _misc_flags.is_contended(); }
 668   void set_is_contended(bool value)        { _misc_flags.set_is_contended(value); }
 669 
 670   // source file name
 671   Symbol* source_file_name() const;
 672   u2 source_file_name_index() const;
 673   void set_source_file_name_index(u2 sourcefile_index);
 674 
 675   // minor and major version numbers of class file
 676   u2 minor_version() const;
 677   void set_minor_version(u2 minor_version);
 678   u2 major_version() const;
 679   void set_major_version(u2 major_version);
 680 
 681   // source debug extension
 682   const char* source_debug_extension() const { return _source_debug_extension; }
 683   void set_source_debug_extension(const char* array, int length);
 684 
 685   // nonstatic oop-map blocks
 686   static int nonstatic_oop_map_size(unsigned int oop_map_count) {
 687     return oop_map_count * OopMapBlock::size_in_words();
 688   }
 689   unsigned int nonstatic_oop_map_count() const {
 690     return _nonstatic_oop_map_size / OopMapBlock::size_in_words();
 691   }
 692   int nonstatic_oop_map_size() const { return _nonstatic_oop_map_size; }
 693   void set_nonstatic_oop_map_size(int words) {
 694     _nonstatic_oop_map_size = words;
 695   }
 696 
 697   bool has_contended_annotations() const { return _misc_flags.has_contended_annotations(); }
 698   void set_has_contended_annotations(bool value)  { _misc_flags.set_has_contended_annotations(value); }
 699 
 700 #if INCLUDE_JVMTI
 701   // Redefinition locking.  Class can only be redefined by one thread at a time.
 702   bool is_being_redefined() const          { return _misc_flags.is_being_redefined(); }
 703   void set_is_being_redefined(bool value)  { _misc_flags.set_is_being_redefined(value); }
 704 
 705   // RedefineClasses() support for previous versions:
 706   void add_previous_version(InstanceKlass* ik, int emcp_method_count);
 707   void purge_previous_version_list();
 708 
 709   InstanceKlass* previous_versions() const { return _previous_versions; }
 710 #else
 711   InstanceKlass* previous_versions() const { return nullptr; }
 712 #endif
 713 
 714   const InstanceKlass* get_klass_version(int version) const;
 715 
 716   bool has_been_redefined() const { return _misc_flags.has_been_redefined(); }
 717   void set_has_been_redefined() { _misc_flags.set_has_been_redefined(true); }
 718 
 719   bool is_scratch_class() const { return _misc_flags.is_scratch_class(); }
 720   void set_is_scratch_class() { _misc_flags.set_is_scratch_class(true); }
 721 
 722   bool has_resolved_methods() const { return _misc_flags.has_resolved_methods(); }
 723   void set_has_resolved_methods()   { _misc_flags.set_has_resolved_methods(true); }
 724   void set_has_resolved_methods(bool value)   { _misc_flags.set_has_resolved_methods(value); }
 725 
 726 public:
 727 #if INCLUDE_JVMTI
 728 
 729   void init_previous_versions() {
 730     _previous_versions = nullptr;
 731   }
 732 
 733  private:
 734   static bool  _should_clean_previous_versions;
 735  public:
 736   static void purge_previous_versions(InstanceKlass* ik) {
 737     if (ik->has_been_redefined()) {
 738       ik->purge_previous_version_list();
 739     }
 740   }
 741 
 742   static bool should_clean_previous_versions_and_reset();
 743   static bool should_clean_previous_versions() { return _should_clean_previous_versions; }
 744 
 745   // JVMTI: Support for caching a class file before it is modified by an agent that can do retransformation
 746   void set_cached_class_file(JvmtiCachedClassFileData *data) {
 747     _cached_class_file = data;
 748   }
 749   JvmtiCachedClassFileData * get_cached_class_file();
 750   jint get_cached_class_file_len();
 751   unsigned char * get_cached_class_file_bytes();
 752 
 753   // JVMTI: Support for caching of field indices, types, and offsets
 754   void set_jvmti_cached_class_field_map(JvmtiCachedClassFieldMap* descriptor) {
 755     _jvmti_cached_class_field_map = descriptor;
 756   }
 757   JvmtiCachedClassFieldMap* jvmti_cached_class_field_map() const {
 758     return _jvmti_cached_class_field_map;
 759   }
 760 #else // INCLUDE_JVMTI
 761 
 762   static void purge_previous_versions(InstanceKlass* ik) { return; };
 763   static bool should_clean_previous_versions_and_reset() { return false; }
 764 
 765   void set_cached_class_file(JvmtiCachedClassFileData *data) {
 766     assert(data == nullptr, "unexpected call with JVMTI disabled");
 767   }
 768   JvmtiCachedClassFileData * get_cached_class_file() { return (JvmtiCachedClassFileData *)nullptr; }
 769 
 770 #endif // INCLUDE_JVMTI
 771 
 772   bool has_nonstatic_concrete_methods() const { return _misc_flags.has_nonstatic_concrete_methods(); }
 773   void set_has_nonstatic_concrete_methods(bool b) { _misc_flags.set_has_nonstatic_concrete_methods(b); }
 774 
 775   bool declares_nonstatic_concrete_methods() const { return _misc_flags.declares_nonstatic_concrete_methods(); }
 776   void set_declares_nonstatic_concrete_methods(bool b) { _misc_flags.set_declares_nonstatic_concrete_methods(b); }
 777 
 778   bool has_miranda_methods () const     { return _misc_flags.has_miranda_methods(); }
 779   void set_has_miranda_methods()        { _misc_flags.set_has_miranda_methods(true); }
 780   bool has_final_method() const         { return _misc_flags.has_final_method(); }
 781   void set_has_final_method()           { _misc_flags.set_has_final_method(true); }
 782 
 783   // for adding methods, ConstMethod::UNSET_IDNUM means no more ids available
 784   inline u2 next_method_idnum();
 785   void set_initial_method_idnum(u2 value)             { _idnum_allocated_count = value; }
 786 
 787   // generics support
 788   Symbol* generic_signature() const;
 789   u2 generic_signature_index() const;
 790   void set_generic_signature_index(u2 sig_index);
 791 
 792   u2 enclosing_method_data(int offset) const;
 793   u2 enclosing_method_class_index() const {
 794     return enclosing_method_data(enclosing_method_class_index_offset);
 795   }
 796   u2 enclosing_method_method_index() {
 797     return enclosing_method_data(enclosing_method_method_index_offset);
 798   }
 799   void set_enclosing_method_indices(u2 class_index,
 800                                     u2 method_index);
 801 
 802   // jmethodID support
 803   jmethodID get_jmethod_id(Method* method);
 804   void make_methods_jmethod_ids();
 805   jmethodID jmethod_id_or_null(Method* method);
 806   void update_methods_jmethod_cache();
 807 
 808   // annotations support
 809   Annotations* annotations() const          { return _annotations; }
 810   void set_annotations(Annotations* anno)   { _annotations = anno; }
 811 
 812   AnnotationArray* class_annotations() const {
 813     return (_annotations != nullptr) ? _annotations->class_annotations() : nullptr;
 814   }
 815   Array<AnnotationArray*>* fields_annotations() const {
 816     return (_annotations != nullptr) ? _annotations->fields_annotations() : nullptr;
 817   }
 818   AnnotationArray* class_type_annotations() const {
 819     return (_annotations != nullptr) ? _annotations->class_type_annotations() : nullptr;
 820   }
 821   Array<AnnotationArray*>* fields_type_annotations() const {
 822     return (_annotations != nullptr) ? _annotations->fields_type_annotations() : nullptr;
 823   }
 824   // allocation
 825   instanceOop allocate_instance(TRAPS);
 826   static instanceOop allocate_instance(oop cls, TRAPS);
 827 
 828   // additional member function to return a handle
 829   instanceHandle allocate_instance_handle(TRAPS);
 830 
 831   // Helper function
 832   static instanceOop register_finalizer(instanceOop i, TRAPS);
 833 
 834   // Check whether reflection/jni/jvm code is allowed to instantiate this class;
 835   // if not, throw either an Error or an Exception.
 836   void check_valid_for_instantiation(bool throwError, TRAPS) override;
 837 
 838   // initialization
 839   void call_class_initializer(TRAPS);
 840   void set_initialization_state_and_notify(ClassState state, TRAPS);
 841 
 842   // OopMapCache support
 843   OopMapCache* oop_map_cache()               { return _oop_map_cache; }
 844   void set_oop_map_cache(OopMapCache *cache) { _oop_map_cache = cache; }
 845   void mask_for(const methodHandle& method, int bci, InterpreterOopMap* entry);
 846 
 847   // JNI identifier support (for static fields - for jni performance)
 848   JNIid* jni_ids()                               { return _jni_ids; }
 849   void set_jni_ids(JNIid* ids)                   { _jni_ids = ids; }
 850   JNIid* jni_id_for(int offset);
 851 
 852  public:
 853   // maintenance of deoptimization dependencies
 854   inline DependencyContext dependencies();
 855   void mark_dependent_nmethods(DeoptimizationScope* deopt_scope, KlassDepChange& changes);
 856   void add_dependent_nmethod(nmethod* nm);
 857   void clean_dependency_context();
 858   // Setup link to hierarchy and deoptimize
 859   void add_to_hierarchy(JavaThread* current);
 860 
 861   // On-stack replacement support
 862   nmethod* osr_nmethods_head() const         { return _osr_nmethods_head; };
 863   void set_osr_nmethods_head(nmethod* h)     { _osr_nmethods_head = h; };
 864   void add_osr_nmethod(nmethod* n);
 865   bool remove_osr_nmethod(nmethod* n);
 866   int mark_osr_nmethods(DeoptimizationScope* deopt_scope, const Method* m);
 867   nmethod* lookup_osr_nmethod(const Method* m, int bci, int level, bool match_level) const;
 868 
 869 #if INCLUDE_JVMTI
 870   // Breakpoint support (see methods on Method* for details)
 871   BreakpointInfo* breakpoints() const       { return _breakpoints; };
 872   void set_breakpoints(BreakpointInfo* bps) { _breakpoints = bps; };
 873 #endif
 874 
 875   // support for stub routines
 876   static ByteSize init_state_offset()  { return byte_offset_of(InstanceKlass, _init_state); }
 877   JFR_ONLY(DEFINE_KLASS_TRACE_ID_OFFSET;)
 878   static ByteSize init_thread_offset() { return byte_offset_of(InstanceKlass, _init_thread); }
 879 
 880   // subclass/subinterface checks
 881   bool implements_interface(Klass* k) const;
 882   bool is_same_or_direct_interface(Klass* k) const;
 883 
 884 #ifdef ASSERT
 885   // check whether this class or one of its superclasses was redefined
 886   bool has_redefined_this_or_super() const;
 887 #endif
 888 
 889   // Access to the implementor of an interface.
 890   InstanceKlass* implementor() const;
 891   void set_implementor(InstanceKlass* ik);
 892   int  nof_implementors() const;
 893   void add_implementor(InstanceKlass* ik);  // ik is a new class that implements this interface
 894   void init_implementor();           // initialize
 895 
 896  private:
 897   // link this class into the implementors list of every interface it implements
 898   void process_interfaces();
 899 
 900  public:
 901   // virtual operations from Klass
 902   GrowableArray<Klass*>* compute_secondary_supers(int num_extra_slots,
 903                                                   Array<InstanceKlass*>* transitive_interfaces) override;
 904   bool can_be_primary_super_slow() const override;
 905   size_t oop_size(oop obj) const override { return size_helper(); }
 906   // slow because it's a virtual call and used for verifying the layout_helper.
 907   // Using the layout_helper bits, we can call is_instance_klass without a virtual call.
 908   DEBUG_ONLY(bool is_instance_klass_slow() const override { return true; })
 909 
 910   // Iterators
 911   void do_local_static_fields(FieldClosure* cl);
 912   void do_nonstatic_fields(FieldClosure* cl); // including inherited fields
 913   void do_local_static_fields(void f(fieldDescriptor*, Handle, TRAPS), Handle, TRAPS);
 914   void print_nonstatic_fields(FieldClosure* cl); // including inherited and injected fields
 915 
 916   void methods_do(void f(Method* method));
 917 
 918   static InstanceKlass* cast(Klass* k) {
 919     return const_cast<InstanceKlass*>(cast(const_cast<const Klass*>(k)));
 920   }
 921 
 922   static const InstanceKlass* cast(const Klass* k) {
 923     assert(k != nullptr, "k should not be null");
 924     assert(k->is_instance_klass(), "cast to InstanceKlass");
 925     return static_cast<const InstanceKlass*>(k);
 926   }
 927 
 928   // This hides Klass::super(). The _super of an InstanceKlass is
 929   // always an InstanceKlass (or nullptr)
 930   InstanceKlass* super() const {
 931     return (Klass::super() == nullptr) ? nullptr : InstanceKlass::cast(Klass::super());
 932   }
 933 
 934   InstanceKlass* java_super() const override {
 935     return InstanceKlass::super();
 936   }
 937 
 938   // Sizing (in words)
 939   static int header_size()            { return sizeof(InstanceKlass)/wordSize; }
 940 
 941   static int size(int vtable_length, int itable_length,
 942                   int nonstatic_oop_map_size,
 943                   bool is_interface) {
 944     return align_metadata_size(header_size() +
 945            vtable_length +
 946            itable_length +
 947            nonstatic_oop_map_size +
 948            (is_interface ? (int)sizeof(Klass*)/wordSize : 0));
 949   }
 950 
 951   int size() const override           { return size(vtable_length(),
 952                                                     itable_length(),
 953                                                     nonstatic_oop_map_size(),
 954                                                     is_interface());
 955   }
 956 
 957 
 958   inline intptr_t* start_of_itable() const;
 959   inline intptr_t* end_of_itable() const;
 960   inline oop static_field_base_raw();
 961 
 962   inline OopMapBlock* start_of_nonstatic_oop_maps() const;
 963   inline Klass** end_of_nonstatic_oop_maps() const;
 964 
 965   inline InstanceKlass* volatile* adr_implementor() const;
 966 
 967   // Use this to return the size of an instance in heap words:
 968   int size_helper() const {
 969     return layout_helper_to_size_helper(layout_helper());
 970   }
 971 
 972   // This bit is initialized in classFileParser.cpp.
 973   // It is false under any of the following conditions:
 974   //  - the class is abstract (including any interface)
 975   //  - the class size is larger than FastAllocateSizeLimit
 976   //  - the class is java/lang/Class, which cannot be allocated directly
 977   bool can_be_fastpath_allocated() const {
 978     return !layout_helper_needs_slow_path(layout_helper());
 979   }
 980 
 981   // Java itable
 982   klassItable itable() const;        // return klassItable wrapper
 983   Method* method_at_itable(InstanceKlass* holder, int index, TRAPS);
 984   Method* method_at_itable_or_null(InstanceKlass* holder, int index, bool& itable_entry_found);
 985   int vtable_index_of_interface_method(Method* method);
 986 
 987 #if INCLUDE_JVMTI
 988   void adjust_default_methods(bool* trace_name_printed);
 989 #endif // INCLUDE_JVMTI
 990 
 991   void clean_weak_instanceklass_links();
 992  private:
 993   void clean_implementors_list();
 994   void clean_method_data();
 995 
 996  public:
 997   // Explicit metaspace deallocation of fields
 998   // For RedefineClasses and class file parsing errors, we need to deallocate
 999   // instanceKlasses and the metadata they point to.
1000   void deallocate_contents(ClassLoaderData* loader_data);
1001   static void deallocate_methods(ClassLoaderData* loader_data,
1002                                  Array<Method*>* methods);
1003   void static deallocate_interfaces(ClassLoaderData* loader_data,
1004                                     const InstanceKlass* super_klass,
1005                                     Array<InstanceKlass*>* local_interfaces,
1006                                     Array<InstanceKlass*>* transitive_interfaces);
1007   void static deallocate_record_components(ClassLoaderData* loader_data,
1008                                            Array<RecordComponent*>* record_component);
1009 
1010   bool on_stack() const override;
1011 
1012   // callbacks for actions during class unloading
1013   static void unload_class(InstanceKlass* ik);
1014 
1015   void release_C_heap_structures(bool release_sub_metadata = true) override;
1016 
1017   // Naming
1018   const char* signature_name() const override;
1019 
1020   // Oop fields (and metadata) iterators
1021   //
1022   // The InstanceKlass iterators also visits the Object's klass.
1023 
1024   // Forward iteration
1025  public:
1026   // Iterate over all oop fields in the oop maps.
1027   template <typename T, class OopClosureType>
1028   inline void oop_oop_iterate_oop_maps(oop obj, OopClosureType* closure);
1029 
1030   // Iterate over all oop fields and metadata.
1031   template <typename T, class OopClosureType>
1032   inline void oop_oop_iterate(oop obj, OopClosureType* closure);
1033 
1034   // Iterate over all oop fields in one oop map.
1035   template <typename T, class OopClosureType>
1036   inline void oop_oop_iterate_oop_map(OopMapBlock* map, oop obj, OopClosureType* closure);
1037 
1038 
1039   // Reverse iteration
1040   // Iterate over all oop fields and metadata.
1041   template <typename T, class OopClosureType>
1042   inline void oop_oop_iterate_reverse(oop obj, OopClosureType* closure);
1043 
1044  private:
1045   // Iterate over all oop fields in the oop maps.
1046   template <typename T, class OopClosureType>
1047   inline void oop_oop_iterate_oop_maps_reverse(oop obj, OopClosureType* closure);
1048 
1049   // Iterate over all oop fields in one oop map.
1050   template <typename T, class OopClosureType>
1051   inline void oop_oop_iterate_oop_map_reverse(OopMapBlock* map, oop obj, OopClosureType* closure);
1052 
1053 
1054   // Bounded range iteration
1055  public:
1056   // Iterate over all oop fields in the oop maps.
1057   template <typename T, class OopClosureType>
1058   inline void oop_oop_iterate_oop_maps_bounded(oop obj, OopClosureType* closure, MemRegion mr);
1059 
1060   // Iterate over all oop fields and metadata.
1061   template <typename T, class OopClosureType>
1062   inline void oop_oop_iterate_bounded(oop obj, OopClosureType* closure, MemRegion mr);
1063 
1064  private:
1065   // Iterate over all oop fields in one oop map.
1066   template <typename T, class OopClosureType>
1067   inline void oop_oop_iterate_oop_map_bounded(OopMapBlock* map, oop obj, OopClosureType* closure, MemRegion mr);
1068 
1069 
1070  public:
1071   u2 idnum_allocated_count() const      { return _idnum_allocated_count; }
1072 
1073 private:
1074   // initialization state
1075   void set_init_state(ClassState state);
1076   void set_rewritten()                  { _misc_flags.set_rewritten(true); }
1077   void set_init_thread(JavaThread *thread)  {
1078     assert((thread == JavaThread::current() && _init_thread == nullptr) ||
1079            (thread == nullptr && _init_thread == JavaThread::current()), "Only one thread is allowed to own initialization");
1080     AtomicAccess::store(&_init_thread, thread);
1081   }
1082 
1083   jmethodID* methods_jmethod_ids_acquire() const;
1084   void release_set_methods_jmethod_ids(jmethodID* jmeths);
1085   // This nulls out obsolete jmethodIDs for all methods in 'klass'.
1086   static void clear_obsolete_jmethod_ids(InstanceKlass* klass);
1087   jmethodID update_jmethod_id(jmethodID* jmeths, Method* method, int idnum);
1088 
1089 public:
1090   // Lock for (1) initialization; (2) access to the ConstantPool of this class.
1091   // Must be one per class and it has to be a VM internal object so java code
1092   // cannot lock it (like the mirror).
1093   // It has to be an object not a Mutex because it's held through java calls.
1094   oop init_lock() const;
1095 
1096   // Returns the array class for the n'th dimension
1097   ArrayKlass* array_klass(int n, TRAPS) override;
1098   ArrayKlass* array_klass_or_null(int n) override;
1099 
1100   // Returns the array class with this class as element type
1101   ArrayKlass* array_klass(TRAPS) override;
1102   ArrayKlass* array_klass_or_null() override;
1103 
1104   static void clean_initialization_error_table();
1105 private:
1106   void fence_and_clear_init_lock();
1107 
1108   bool link_class_impl                           (TRAPS);
1109   bool verify_code                               (TRAPS);
1110   void initialize_impl                           (TRAPS);
1111   void initialize_super_interfaces               (TRAPS);
1112 
1113   void add_initialization_error(JavaThread* current, Handle exception);
1114   oop get_initialization_error(JavaThread* current);
1115 
1116   // find a local method (returns null if not found)
1117   Method* find_method_impl(const Symbol* name,
1118                            const Symbol* signature,
1119                            OverpassLookupMode overpass_mode,
1120                            StaticLookupMode static_mode,
1121                            PrivateLookupMode private_mode) const;
1122 
1123   static Method* find_method_impl(const Array<Method*>* methods,
1124                                   const Symbol* name,
1125                                   const Symbol* signature,
1126                                   OverpassLookupMode overpass_mode,
1127                                   StaticLookupMode static_mode,
1128                                   PrivateLookupMode private_mode);
1129 
1130 #if INCLUDE_JVMTI
1131   // RedefineClasses support
1132   void link_previous_versions(InstanceKlass* pv) { _previous_versions = pv; }
1133   void mark_newly_obsolete_methods(Array<Method*>* old_methods, int emcp_method_count);
1134 #endif
1135 public:
1136 
1137 #if INCLUDE_CDS
1138   // CDS support - remove and restore oops from metadata. Oops are not shared.
1139   void remove_unshareable_info() override;
1140   void remove_unshareable_flags();
1141   void remove_java_mirror() override;
1142   void restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, PackageEntry* pkg_entry, TRAPS);
1143   void init_shared_package_entry();
1144   bool can_be_verified_at_dumptime() const;
1145   void compute_has_loops_flag_for_methods();
1146 #endif
1147   bool     has_init_deps_processed() const { return _misc_flags.has_init_deps_processed(); }
1148   void set_has_init_deps_processed() {
1149     assert(is_initialized(), "");
1150     assert(!has_init_deps_processed(), "already set"); // one-off action
1151     _misc_flags.set_has_init_deps_processed(true);
1152   }
1153 
1154   u2 compute_modifier_flags() const override;
1155 
1156 public:
1157   // JVMTI support
1158   jint jvmti_class_status() const override;
1159 
1160   void metaspace_pointers_do(MetaspaceClosure* iter) override;
1161 
1162  public:
1163   // Printing
1164   void print_on(outputStream* st) const override;
1165   void print_value_on(outputStream* st) const override;
1166   void print_class_flags(outputStream* st) const;
1167 
1168   void oop_print_value_on(oop obj, outputStream* st) override;
1169 
1170   void oop_print_on      (oop obj, outputStream* st) override;
1171 
1172 #ifndef PRODUCT
1173   void print_dependent_nmethods(bool verbose = false);
1174   bool is_dependent_nmethod(nmethod* nm);
1175   bool verify_itable_index(int index);
1176 #endif
1177 
1178   const char* internal_name() const override;
1179 
1180   // Verification
1181   void verify_on(outputStream* st) override;
1182 
1183   void oop_verify_on(oop obj, outputStream* st) override;
1184 
1185   // Logging
1186   void print_class_load_logging(ClassLoaderData* loader_data,
1187                                 const ModuleEntry* module_entry,
1188                                 const ClassFileStream* cfs) const;
1189  private:
1190   void print_class_load_cause_logging() const;
1191   void print_class_load_helper(ClassLoaderData* loader_data,
1192                                const ModuleEntry* module_entry,
1193                                const ClassFileStream* cfs) const;
1194 };
1195 
1196 // for adding methods
1197 // UNSET_IDNUM return means no more ids available
1198 inline u2 InstanceKlass::next_method_idnum() {
1199   if (_idnum_allocated_count == ConstMethod::MAX_IDNUM) {
1200     return ConstMethod::UNSET_IDNUM; // no more ids available
1201   } else {
1202     return _idnum_allocated_count++;
1203   }
1204 }
1205 
1206 class PrintClassClosure : public KlassClosure {
1207 private:
1208   outputStream* _st;
1209   bool _verbose;
1210 public:
1211   PrintClassClosure(outputStream* st, bool verbose);
1212 
1213   void do_klass(Klass* k);
1214 };
1215 
1216 /* JNIid class for jfieldIDs only */
1217 class JNIid: public CHeapObj<mtClass> {
1218   friend class VMStructs;
1219  private:
1220   InstanceKlass*     _holder;
1221   JNIid*             _next;
1222   int                _offset;
1223 #ifdef ASSERT
1224   bool               _is_static_field_id;
1225 #endif
1226 
1227  public:
1228   // Accessors
1229   InstanceKlass* holder() const   { return _holder; }
1230   int offset() const              { return _offset; }
1231   JNIid* next()                   { return _next; }
1232   // Constructor
1233   JNIid(InstanceKlass* holder, int offset, JNIid* next);
1234   // Identifier lookup
1235   JNIid* find(int offset);
1236 
1237   bool find_local_field(fieldDescriptor* fd) {
1238     return InstanceKlass::cast(holder())->find_local_field_from_offset(offset(), true, fd);
1239   }
1240 
1241   static void deallocate(JNIid* id);
1242   // Debugging
1243 #ifdef ASSERT
1244   bool is_static_field_id() const { return _is_static_field_id; }
1245   void set_is_static_field_id()   { _is_static_field_id = true; }
1246 #endif
1247   void verify(InstanceKlass* holder);
1248 };
1249 
1250 // An iterator that's used to access the inner classes indices in the
1251 // InstanceKlass::_inner_classes array.
1252 class InnerClassesIterator : public StackObj {
1253  private:
1254   Array<jushort>* _inner_classes;
1255   int _length;
1256   int _idx;
1257  public:
1258 
1259   InnerClassesIterator(const InstanceKlass* k) {
1260     _inner_classes = k->inner_classes();
1261     if (k->inner_classes() != nullptr) {
1262       _length = _inner_classes->length();
1263       // The inner class array's length should be the multiple of
1264       // inner_class_next_offset if it only contains the InnerClasses
1265       // attribute data, or it should be
1266       // n*inner_class_next_offset+enclosing_method_attribute_size
1267       // if it also contains the EnclosingMethod data.
1268       assert((_length % InstanceKlass::inner_class_next_offset == 0 ||
1269               _length % InstanceKlass::inner_class_next_offset == InstanceKlass::enclosing_method_attribute_size),
1270              "just checking");
1271       // Remove the enclosing_method portion if exists.
1272       if (_length % InstanceKlass::inner_class_next_offset == InstanceKlass::enclosing_method_attribute_size) {
1273         _length -= InstanceKlass::enclosing_method_attribute_size;
1274       }
1275     } else {
1276       _length = 0;
1277     }
1278     _idx = 0;
1279   }
1280 
1281   int length() const {
1282     return _length;
1283   }
1284 
1285   void next() {
1286     _idx += InstanceKlass::inner_class_next_offset;
1287   }
1288 
1289   bool done() const {
1290     return (_idx >= _length);
1291   }
1292 
1293   u2 inner_class_info_index() const {
1294     return _inner_classes->at(
1295                _idx + InstanceKlass::inner_class_inner_class_info_offset);
1296   }
1297 
1298   void set_inner_class_info_index(u2 index) {
1299     _inner_classes->at_put(
1300                _idx + InstanceKlass::inner_class_inner_class_info_offset, index);
1301   }
1302 
1303   u2 outer_class_info_index() const {
1304     return _inner_classes->at(
1305                _idx + InstanceKlass::inner_class_outer_class_info_offset);
1306   }
1307 
1308   void set_outer_class_info_index(u2 index) {
1309     _inner_classes->at_put(
1310                _idx + InstanceKlass::inner_class_outer_class_info_offset, index);
1311   }
1312 
1313   u2 inner_name_index() const {
1314     return _inner_classes->at(
1315                _idx + InstanceKlass::inner_class_inner_name_offset);
1316   }
1317 
1318   void set_inner_name_index(u2 index) {
1319     _inner_classes->at_put(
1320                _idx + InstanceKlass::inner_class_inner_name_offset, index);
1321   }
1322 
1323   u2 inner_access_flags() const {
1324     return _inner_classes->at(
1325                _idx + InstanceKlass::inner_class_access_flags_offset);
1326   }
1327 };
1328 
1329 // Iterator over class hierarchy under a particular class. Implements depth-first pre-order traversal.
1330 // Usage:
1331 //  for (ClassHierarchyIterator iter(root_klass); !iter.done(); iter.next()) {
1332 //    Klass* k = iter.klass();
1333 //    ...
1334 //  }
1335 class ClassHierarchyIterator : public StackObj {
1336  private:
1337   InstanceKlass* _root;
1338   Klass*         _current;
1339   bool           _visit_subclasses;
1340 
1341  public:
1342   ClassHierarchyIterator(InstanceKlass* root) : _root(root), _current(root), _visit_subclasses(true) {
1343     assert(_root == _current, "required"); // initial state
1344   }
1345 
1346   bool done() {
1347     return (_current == nullptr);
1348   }
1349 
1350   // Make a step iterating over the class hierarchy under the root class.
1351   // Skips subclasses if requested.
1352   void next();
1353 
1354   Klass* klass() {
1355     assert(!done(), "sanity");
1356     return _current;
1357   }
1358 
1359   // Skip subclasses of the current class.
1360   void skip_subclasses() {
1361     _visit_subclasses = false;
1362   }
1363 };
1364 
1365 #endif // SHARE_OOPS_INSTANCEKLASS_HPP