1 /*
   2  * Copyright (c) 1997, 2023, 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/referenceType.hpp"
  29 #include "oops/annotations.hpp"
  30 #include "oops/constMethod.hpp"
  31 #include "oops/fieldInfo.hpp"
  32 #include "oops/instanceKlassFlags.hpp"
  33 #include "oops/instanceOop.hpp"
  34 #include "runtime/handles.hpp"
  35 #include "runtime/javaThread.hpp"
  36 #include "utilities/accessFlags.hpp"
  37 #include "utilities/align.hpp"
  38 #include "utilities/growableArray.hpp"
  39 #include "utilities/macros.hpp"
  40 #if INCLUDE_JFR
  41 #include "jfr/support/jfrKlassExtension.hpp"
  42 #endif
  43 
  44 class ConstantPool;
  45 class DeoptimizationScope;
  46 class klassItable;
  47 class Monitor;
  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 jniIdMapBase;
  71 class JNIid;
  72 class JvmtiCachedClassFieldMap;
  73 class nmethodBucket;
  74 class OopMapCache;
  75 class InterpreterOopMap;
  76 class PackageEntry;
  77 class ModuleEntry;
  78 
  79 // This is used in iterators below.
  80 class FieldClosure: public StackObj {
  81 public:
  82   virtual void do_field(fieldDescriptor* fd) = 0;
  83 };
  84 
  85 // Print fields.
  86 // If "obj" argument to constructor is null, prints static fields, otherwise prints non-static fields.
  87 class FieldPrinter: public FieldClosure {
  88    oop _obj;
  89    outputStream* _st;
  90  public:
  91    FieldPrinter(outputStream* st, oop obj = nullptr) : _obj(obj), _st(st) {}
  92    void do_field(fieldDescriptor* fd);
  93 };
  94 
  95 // Describes where oops are located in instances of this klass.
  96 class OopMapBlock {
  97  public:
  98   // Byte offset of the first oop mapped by this block.
  99   int offset() const          { return _offset; }
 100   void set_offset(int offset) { _offset = offset; }
 101 
 102   // Number of oops in this block.
 103   uint count() const         { return _count; }
 104   void set_count(uint count) { _count = count; }
 105 
 106   void increment_count(int diff) { _count += diff; }
 107 
 108   int offset_span() const { return _count * heapOopSize; }
 109 
 110   int end_offset() const {
 111     return offset() + offset_span();
 112   }
 113 
 114   bool is_contiguous(int another_offset) const {
 115     return another_offset == end_offset();
 116   }
 117 
 118   // sizeof(OopMapBlock) in words.
 119   static int size_in_words() {
 120     return align_up((int)sizeof(OopMapBlock), wordSize) >>
 121       LogBytesPerWord;
 122   }
 123 
 124   static int compare_offset(const OopMapBlock* a, const OopMapBlock* b) {
 125     return a->offset() - b->offset();
 126   }
 127 
 128  private:
 129   int  _offset;
 130   uint _count;
 131 };
 132 
 133 struct JvmtiCachedClassFileData;
 134 
 135 class InstanceKlass: public Klass {
 136   friend class VMStructs;
 137   friend class JVMCIVMStructs;
 138   friend class ClassFileParser;
 139   friend class CompileReplay;
 140 
 141  public:
 142   static const KlassKind Kind = InstanceKlassKind;
 143 
 144  protected:
 145   InstanceKlass(const ClassFileParser& parser, KlassKind kind = Kind, ReferenceType reference_type = REF_NONE);
 146 
 147  public:
 148   InstanceKlass();
 149 
 150   // See "The Java Virtual Machine Specification" section 2.16.2-5 for a detailed description
 151   // of the class loading & initialization procedure, and the use of the states.
 152   enum ClassState : u1 {
 153     allocated,                          // allocated (but not yet linked)
 154     loaded,                             // loaded and inserted in class hierarchy (but not linked yet)
 155     being_linked,                       // currently running verifier and rewriter
 156     linked,                             // successfully linked/verified (but not initialized yet)
 157     being_initialized,                  // currently running class initializer
 158     fully_initialized,                  // initialized (successful final state)
 159     initialization_error                // error happened during initialization
 160   };
 161 
 162  private:
 163   static InstanceKlass* allocate_instance_klass(const ClassFileParser& parser, TRAPS);
 164 
 165  protected:
 166   // If you add a new field that points to any metaspace object, you
 167   // must add this field to InstanceKlass::metaspace_pointers_do().
 168 
 169   // Annotations for this class
 170   Annotations*    _annotations;
 171   // Package this class is defined in
 172   PackageEntry*   _package_entry;
 173   // Array classes holding elements of this class.
 174   ObjArrayKlass* volatile _array_klasses;
 175   // Constant pool for this class.
 176   ConstantPool* _constants;
 177   // The InnerClasses attribute and EnclosingMethod attribute. The
 178   // _inner_classes is an array of shorts. If the class has InnerClasses
 179   // attribute, then the _inner_classes array begins with 4-tuples of shorts
 180   // [inner_class_info_index, outer_class_info_index,
 181   // inner_name_index, inner_class_access_flags] for the InnerClasses
 182   // attribute. If the EnclosingMethod attribute exists, it occupies the
 183   // last two shorts [class_index, method_index] of the array. If only
 184   // the InnerClasses attribute exists, the _inner_classes array length is
 185   // number_of_inner_classes * 4. If the class has both InnerClasses
 186   // and EnclosingMethod attributes the _inner_classes array length is
 187   // number_of_inner_classes * 4 + enclosing_method_attribute_size.
 188   Array<jushort>* _inner_classes;
 189 
 190   // The NestMembers attribute. An array of shorts, where each is a
 191   // class info index for the class that is a nest member. This data
 192   // has not been validated.
 193   Array<jushort>* _nest_members;
 194 
 195   // Resolved nest-host klass: either true nest-host or self if we are not
 196   // nested, or an error occurred resolving or validating the nominated
 197   // nest-host. Can also be set directly by JDK API's that establish nest
 198   // relationships.
 199   // By always being set it makes nest-member access checks simpler.
 200   InstanceKlass* _nest_host;
 201 
 202   // The PermittedSubclasses attribute. An array of shorts, where each is a
 203   // class info index for the class that is a permitted subclass.
 204   Array<jushort>* _permitted_subclasses;
 205 
 206   // The contents of the Record attribute.
 207   Array<RecordComponent*>* _record_components;
 208 
 209   // the source debug extension for this klass, null if not specified.
 210   // Specified as UTF-8 string without terminating zero byte in the classfile,
 211   // it is stored in the instanceklass as a null-terminated UTF-8 string
 212   const char*     _source_debug_extension;
 213 
 214   // Number of heapOopSize words used by non-static fields in this klass
 215   // (including inherited fields but after header_size()).
 216   int             _nonstatic_field_size;
 217   int             _static_field_size;       // number words used by static fields (oop and non-oop) in this klass
 218   int             _nonstatic_oop_map_size;  // size in words of nonstatic oop map blocks
 219   int             _itable_len;              // length of Java itable (in words)
 220 
 221   // The NestHost attribute. The class info index for the class
 222   // that is the nest-host of this class. This data has not been validated.
 223   u2              _nest_host_index;
 224   u2              _this_class_index;        // constant pool entry
 225   u2              _static_oop_field_count;  // number of static oop fields in this klass
 226   u2              _nonstatic_oop_field_count;// number of non-static oop fields in this klass
 227   u2              _java_fields_count;       // The number of declared Java fields
 228 
 229   volatile u2     _idnum_allocated_count;   // JNI/JVMTI: increments with the addition of methods, old ids don't change
 230 
 231   volatile ClassState _init_state;          // state of class
 232 
 233   u1              _reference_type;          // reference type
 234 
 235   // State is set either at parse time or while executing, atomically to not disturb other state
 236   InstanceKlassFlags _misc_flags;
 237 
 238   Monitor*             _init_monitor;       // mutual exclusion to _init_state and _init_thread.
 239   JavaThread* volatile _init_thread;        // Pointer to current thread doing initialization (to handle recursive initialization)
 240 
 241   OopMapCache*    volatile _oop_map_cache;   // OopMapCache for all methods in the klass (allocated lazily)
 242   JNIid*          _jni_ids;              // First JNI identifier for static fields in this class
 243   jmethodID*      volatile _methods_jmethod_ids;  // jmethodIDs corresponding to method_idnum, or null if none
 244   nmethodBucket*  volatile _dep_context;          // packed DependencyContext structure
 245   uint64_t        volatile _dep_context_last_cleaned;
 246   nmethod*        _osr_nmethods_head;    // Head of list of on-stack replacement nmethods for this class
 247 #if INCLUDE_JVMTI
 248   BreakpointInfo* _breakpoints;          // bpt lists, managed by Method*
 249   // Linked instanceKlasses of previous versions
 250   InstanceKlass* _previous_versions;
 251   // JVMTI fields can be moved to their own structure - see 6315920
 252   // JVMTI: cached class file, before retransformable agent modified it in CFLH
 253   JvmtiCachedClassFileData* _cached_class_file;
 254 #endif
 255 
 256 #if INCLUDE_JVMTI
 257   JvmtiCachedClassFieldMap* _jvmti_cached_class_field_map;  // JVMTI: used during heap iteration
 258 #endif
 259 
 260   NOT_PRODUCT(int _verify_count;)  // to avoid redundant verifies
 261   NOT_PRODUCT(volatile int _shared_class_load_count;) // ensure a shared class is loaded only once
 262 
 263   // Method array.
 264   Array<Method*>* _methods;
 265   // Default Method Array, concrete methods inherited from interfaces
 266   Array<Method*>* _default_methods;
 267   // Interfaces (InstanceKlass*s) this class declares locally to implement.
 268   Array<InstanceKlass*>* _local_interfaces;
 269   // Interfaces (InstanceKlass*s) this class implements transitively.
 270   Array<InstanceKlass*>* _transitive_interfaces;
 271   // Int array containing the original order of method in the class file (for JVMTI).
 272   Array<int>*     _method_ordering;
 273   // Int array containing the vtable_indices for default_methods
 274   // offset matches _default_methods offset
 275   Array<int>*     _default_vtable_indices;
 276 
 277   // Fields information is stored in an UNSIGNED5 encoded stream (see fieldInfo.hpp)
 278   Array<u1>*          _fieldinfo_stream;
 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   // The three BUILTIN class loader types
 310   bool is_shared_boot_class() const { return _misc_flags.is_shared_boot_class(); }
 311   bool is_shared_platform_class() const { return _misc_flags.is_shared_platform_class(); }
 312   bool is_shared_app_class() const {  return _misc_flags.is_shared_app_class(); }
 313   // The UNREGISTERED class loader type
 314   bool is_shared_unregistered_class() const { return _misc_flags.is_shared_unregistered_class(); }
 315 
 316   // Check if the class can be shared in CDS
 317   bool is_shareable() const;
 318 
 319   bool shared_loading_failed() const { return _misc_flags.shared_loading_failed(); }
 320 
 321   void set_shared_loading_failed() { _misc_flags.set_shared_loading_failed(true); }
 322 
 323 #if INCLUDE_CDS
 324   void set_shared_class_loader_type(s2 loader_type) { _misc_flags.set_shared_class_loader_type(loader_type); }
 325   void assign_class_loader_type() { _misc_flags.assign_class_loader_type(_class_loader_data); }
 326 #endif
 327 
 328   bool has_nonstatic_fields() const        { return _misc_flags.has_nonstatic_fields(); }
 329   void set_has_nonstatic_fields(bool b)    { _misc_flags.set_has_nonstatic_fields(b); }
 330 
 331   bool has_localvariable_table() const     { return _misc_flags.has_localvariable_table(); }
 332   void set_has_localvariable_table(bool b) { _misc_flags.set_has_localvariable_table(b); }
 333 
 334   // field sizes
 335   int nonstatic_field_size() const         { return _nonstatic_field_size; }
 336   void set_nonstatic_field_size(int size)  { _nonstatic_field_size = size; }
 337 
 338   int static_field_size() const            { return _static_field_size; }
 339   void set_static_field_size(int size)     { _static_field_size = size; }
 340 
 341   int static_oop_field_count() const       { return (int)_static_oop_field_count; }
 342   void set_static_oop_field_count(u2 size) { _static_oop_field_count = size; }
 343 
 344   int nonstatic_oop_field_count() const       { return (int)_nonstatic_oop_field_count; }
 345   void set_nonstatic_oop_field_count(u2 size) { _nonstatic_oop_field_count = size; }
 346 
 347   // Java itable
 348   int  itable_length() const               { return _itable_len; }
 349   void set_itable_length(int len)          { _itable_len = len; }
 350 
 351   // array klasses
 352   ObjArrayKlass* array_klasses() const     { return _array_klasses; }
 353   inline ObjArrayKlass* array_klasses_acquire() const; // load with acquire semantics
 354   inline void release_set_array_klasses(ObjArrayKlass* k); // store with release semantics
 355   void set_array_klasses(ObjArrayKlass* k) { _array_klasses = k; }
 356 
 357   // methods
 358   Array<Method*>* methods() const          { return _methods; }
 359   void set_methods(Array<Method*>* a)      { _methods = a; }
 360   Method* method_with_idnum(int idnum);
 361   Method* method_with_orig_idnum(int idnum);
 362   Method* method_with_orig_idnum(int idnum, int version);
 363 
 364   // method ordering
 365   Array<int>* method_ordering() const     { return _method_ordering; }
 366   void set_method_ordering(Array<int>* m) { _method_ordering = m; }
 367   void copy_method_ordering(const intArray* m, TRAPS);
 368 
 369   // default_methods
 370   Array<Method*>* default_methods() const  { return _default_methods; }
 371   void set_default_methods(Array<Method*>* a) { _default_methods = a; }
 372 
 373   // default method vtable_indices
 374   Array<int>* default_vtable_indices() const { return _default_vtable_indices; }
 375   void set_default_vtable_indices(Array<int>* v) { _default_vtable_indices = v; }
 376   Array<int>* create_new_default_vtable_indices(int len, TRAPS);
 377 
 378   // interfaces
 379   Array<InstanceKlass*>* local_interfaces() const          { return _local_interfaces; }
 380   void set_local_interfaces(Array<InstanceKlass*>* a)      {
 381     guarantee(_local_interfaces == nullptr || a == nullptr, "Just checking");
 382     _local_interfaces = a; }
 383 
 384   Array<InstanceKlass*>* transitive_interfaces() const     { return _transitive_interfaces; }
 385   void set_transitive_interfaces(Array<InstanceKlass*>* a) {
 386     guarantee(_transitive_interfaces == nullptr || a == nullptr, "Just checking");
 387     _transitive_interfaces = a;
 388   }
 389 
 390  private:
 391   friend class fieldDescriptor;
 392   FieldInfo field(int index) const;
 393 
 394  public:
 395   int     field_offset      (int index) const { return field(index).offset(); }
 396   int     field_access_flags(int index) const { return field(index).access_flags().as_int(); }
 397   FieldInfo::FieldFlags field_flags(int index) const { return field(index).field_flags(); }
 398   FieldStatus field_status(int index)   const { return fields_status()->at(index); }
 399   inline Symbol* field_name        (int index) const;
 400   inline Symbol* field_signature   (int index) const;
 401 
 402   // Number of Java declared fields
 403   int java_fields_count() const;
 404   int total_fields_count() const;
 405 
 406   Array<u1>* fieldinfo_stream() const { return _fieldinfo_stream; }
 407   void set_fieldinfo_stream(Array<u1>* fis) { _fieldinfo_stream = fis; }
 408 
 409   Array<FieldStatus>* fields_status() const {return _fields_status; }
 410   void set_fields_status(Array<FieldStatus>* array) { _fields_status = array; }
 411 
 412   // inner classes
 413   Array<u2>* inner_classes() const       { return _inner_classes; }
 414   void set_inner_classes(Array<u2>* f)   { _inner_classes = f; }
 415 
 416   // nest members
 417   Array<u2>* nest_members() const     { return _nest_members; }
 418   void set_nest_members(Array<u2>* m) { _nest_members = m; }
 419 
 420   // nest-host index
 421   jushort nest_host_index() const { return _nest_host_index; }
 422   void set_nest_host_index(u2 i)  { _nest_host_index = i; }
 423   // dynamic nest member support
 424   void set_nest_host(InstanceKlass* host);
 425 
 426   // record components
 427   Array<RecordComponent*>* record_components() const { return _record_components; }
 428   void set_record_components(Array<RecordComponent*>* record_components) {
 429     _record_components = record_components;
 430   }
 431   bool is_record() const;
 432 
 433   // permitted subclasses
 434   Array<u2>* permitted_subclasses() const     { return _permitted_subclasses; }
 435   void set_permitted_subclasses(Array<u2>* s) { _permitted_subclasses = s; }
 436 
 437 private:
 438   // Called to verify that k is a member of this nest - does not look at k's nest-host,
 439   // nor does it resolve any CP entries or load any classes.
 440   bool has_nest_member(JavaThread* current, InstanceKlass* k) const;
 441 
 442 public:
 443   // Call this only if you know that the nest host has been initialized.
 444   InstanceKlass* nest_host_not_null() {
 445     assert(_nest_host != nullptr, "must be");
 446     return _nest_host;
 447   }
 448   // Used to construct informative IllegalAccessError messages at a higher level,
 449   // if there was an issue resolving or validating the nest host.
 450   // Returns null if there was no error.
 451   const char* nest_host_error();
 452   // Returns nest-host class, resolving and validating it if needed.
 453   // Returns null if resolution is not possible from the calling context.
 454   InstanceKlass* nest_host(TRAPS);
 455   // Check if this klass is a nestmate of k - resolves this nest-host and k's
 456   bool has_nestmate_access_to(InstanceKlass* k, TRAPS);
 457 
 458   // Called to verify that k is a permitted subclass of this class
 459   bool has_as_permitted_subclass(const InstanceKlass* k) const;
 460 
 461   enum InnerClassAttributeOffset {
 462     // From http://mirror.eng/products/jdk/1.1/docs/guide/innerclasses/spec/innerclasses.doc10.html#18814
 463     inner_class_inner_class_info_offset = 0,
 464     inner_class_outer_class_info_offset = 1,
 465     inner_class_inner_name_offset = 2,
 466     inner_class_access_flags_offset = 3,
 467     inner_class_next_offset = 4
 468   };
 469 
 470   enum EnclosingMethodAttributeOffset {
 471     enclosing_method_class_index_offset = 0,
 472     enclosing_method_method_index_offset = 1,
 473     enclosing_method_attribute_size = 2
 474   };
 475 
 476   // package
 477   PackageEntry* package() const     { return _package_entry; }
 478   ModuleEntry* module() const;
 479   bool in_unnamed_package() const   { return (_package_entry == nullptr); }
 480   void set_package(ClassLoaderData* loader_data, PackageEntry* pkg_entry, TRAPS);
 481   // If the package for the InstanceKlass is in the boot loader's package entry
 482   // table then sets the classpath_index field so that
 483   // get_system_package() will know to return a non-null value for the
 484   // package's location.  And, so that the package will be added to the list of
 485   // packages returned by get_system_packages().
 486   // For packages whose classes are loaded from the boot loader class path, the
 487   // classpath_index indicates which entry on the boot loader class path.
 488   void set_classpath_index(s2 path_index);
 489   bool is_same_class_package(const Klass* class2) const;
 490   bool is_same_class_package(oop other_class_loader, const Symbol* other_class_name) const;
 491 
 492   // find an enclosing class
 493   InstanceKlass* compute_enclosing_class(bool* inner_is_member, TRAPS) const;
 494 
 495   // Find InnerClasses attribute and return outer_class_info_index & inner_name_index.
 496   bool find_inner_classes_attr(int* ooff, int* noff, TRAPS) const;
 497 
 498  private:
 499   // Check prohibited package ("java/" only loadable by boot or platform loaders)
 500   static void check_prohibited_package(Symbol* class_name,
 501                                        ClassLoaderData* loader_data,
 502                                        TRAPS);
 503 
 504   JavaThread* init_thread()  { return Atomic::load(&_init_thread); }
 505   // We can safely access the name as long as we hold the _init_monitor.
 506   const char* init_thread_name() {
 507     assert(_init_monitor->owned_by_self(), "Must hold _init_monitor here");
 508     return init_thread()->name_raw();
 509   }
 510 
 511  public:
 512   // initialization state
 513   bool is_loaded() const                   { return init_state() >= loaded; }
 514   bool is_linked() const                   { return init_state() >= linked; }
 515   bool is_being_linked() const             { return init_state() == being_linked; }
 516   bool is_initialized() const              { return init_state() == fully_initialized; }
 517   bool is_not_initialized() const          { return init_state() <  being_initialized; }
 518   bool is_being_initialized() const        { return init_state() == being_initialized; }
 519   bool is_in_error_state() const           { return init_state() == initialization_error; }
 520   bool is_init_thread(JavaThread *thread)  { return thread == init_thread(); }
 521   ClassState  init_state() const           { return Atomic::load(&_init_state); }
 522   const char* init_state_name() const;
 523   bool is_rewritten() const                { return _misc_flags.rewritten(); }
 524 
 525   class LockLinkState : public StackObj {
 526     InstanceKlass* _ik;
 527     JavaThread*    _current;
 528    public:
 529     LockLinkState(InstanceKlass* ik, JavaThread* current) : _ik(ik), _current(current) {
 530       ik->check_link_state_and_wait(current);
 531     }
 532     ~LockLinkState() {
 533       if (!_ik->is_linked()) {
 534         // Reset to loaded if linking failed.
 535         _ik->set_initialization_state_and_notify(loaded, _current);
 536       }
 537     }
 538   };
 539 
 540   // is this a sealed class
 541   bool is_sealed() const;
 542 
 543   // defineClass specified verification
 544   bool should_verify_class() const         { return _misc_flags.should_verify_class(); }
 545   void set_should_verify_class(bool value) { _misc_flags.set_should_verify_class(value); }
 546 
 547   // marking
 548   bool is_marked_dependent() const         { return _misc_flags.is_marked_dependent(); }
 549   void set_is_marked_dependent(bool value) { _misc_flags.set_is_marked_dependent(value); }
 550 
 551   // initialization (virtuals from Klass)
 552   bool should_be_initialized() const;  // means that initialize should be called
 553   void initialize(TRAPS);
 554   void link_class(TRAPS);
 555   bool link_class_or_fail(TRAPS); // returns false on failure
 556   void rewrite_class(TRAPS);
 557   void link_methods(TRAPS);
 558   Method* class_initializer() const;
 559 
 560   // reference type
 561   ReferenceType reference_type() const     { return (ReferenceType)_reference_type; }
 562 
 563   // this class cp index
 564   u2 this_class_index() const             { return _this_class_index; }
 565   void set_this_class_index(u2 index)     { _this_class_index = index; }
 566 
 567   static ByteSize reference_type_offset() { return byte_offset_of(InstanceKlass, _reference_type); }
 568 
 569   // find local field, returns true if found
 570   bool find_local_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const;
 571   // find field in direct superinterfaces, returns the interface in which the field is defined
 572   Klass* find_interface_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const;
 573   // find field according to JVM spec 5.4.3.2, returns the klass in which the field is defined
 574   Klass* find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const;
 575   // find instance or static fields according to JVM spec 5.4.3.2, returns the klass in which the field is defined
 576   Klass* find_field(Symbol* name, Symbol* sig, bool is_static, fieldDescriptor* fd) const;
 577 
 578   // find a non-static or static field given its offset within the class.
 579   bool contains_field_offset(int offset);
 580 
 581   bool find_local_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const;
 582   bool find_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const;
 583 
 584  private:
 585   inline static int quick_search(const Array<Method*>* methods, const Symbol* name);
 586 
 587  public:
 588   static void disable_method_binary_search() {
 589     _disable_method_binary_search = true;
 590   }
 591 
 592   // find a local method (returns null if not found)
 593   Method* find_method(const Symbol* name, const Symbol* signature) const;
 594   static Method* find_method(const Array<Method*>* methods,
 595                              const Symbol* name,
 596                              const Symbol* signature);
 597 
 598   // find a local method, but skip static methods
 599   Method* find_instance_method(const Symbol* name, const Symbol* signature,
 600                                PrivateLookupMode private_mode) const;
 601   static Method* find_instance_method(const Array<Method*>* methods,
 602                                       const Symbol* name,
 603                                       const Symbol* signature,
 604                                       PrivateLookupMode private_mode);
 605 
 606   // find a local method (returns null if not found)
 607   Method* find_local_method(const Symbol* name,
 608                             const Symbol* signature,
 609                             OverpassLookupMode overpass_mode,
 610                             StaticLookupMode static_mode,
 611                             PrivateLookupMode private_mode) const;
 612 
 613   // find a local method from given methods array (returns null if not found)
 614   static Method* find_local_method(const Array<Method*>* methods,
 615                                    const Symbol* name,
 616                                    const Symbol* signature,
 617                                    OverpassLookupMode overpass_mode,
 618                                    StaticLookupMode static_mode,
 619                                    PrivateLookupMode private_mode);
 620 
 621   // find a local method index in methods or default_methods (returns -1 if not found)
 622   static int find_method_index(const Array<Method*>* methods,
 623                                const Symbol* name,
 624                                const Symbol* signature,
 625                                OverpassLookupMode overpass_mode,
 626                                StaticLookupMode static_mode,
 627                                PrivateLookupMode private_mode);
 628 
 629   // lookup operation (returns null if not found)
 630   Method* uncached_lookup_method(const Symbol* name,
 631                                  const Symbol* signature,
 632                                  OverpassLookupMode overpass_mode,
 633                                  PrivateLookupMode private_mode = PrivateLookupMode::find) const;
 634 
 635   // lookup a method in all the interfaces that this class implements
 636   // (returns null if not found)
 637   Method* lookup_method_in_all_interfaces(Symbol* name, Symbol* signature, DefaultsLookupMode defaults_mode) const;
 638 
 639   // lookup a method in local defaults then in all interfaces
 640   // (returns null if not found)
 641   Method* lookup_method_in_ordered_interfaces(Symbol* name, Symbol* signature) const;
 642 
 643   // Find method indices by name.  If a method with the specified name is
 644   // found the index to the first method is returned, and 'end' is filled in
 645   // with the index of first non-name-matching method.  If no method is found
 646   // -1 is returned.
 647   int find_method_by_name(const Symbol* name, int* end) const;
 648   static int find_method_by_name(const Array<Method*>* methods,
 649                                  const Symbol* name, int* end);
 650 
 651   // constant pool
 652   ConstantPool* constants() const        { return _constants; }
 653   void set_constants(ConstantPool* c)    { _constants = c; }
 654 
 655   // protection domain
 656   oop protection_domain() const;
 657 
 658   // signers
 659   objArrayOop signers() const;
 660 
 661   bool is_contended() const                { return _misc_flags.is_contended(); }
 662   void set_is_contended(bool value)        { _misc_flags.set_is_contended(value); }
 663 
 664   // source file name
 665   Symbol* source_file_name() const;
 666   u2 source_file_name_index() const;
 667   void set_source_file_name_index(u2 sourcefile_index);
 668 
 669   // minor and major version numbers of class file
 670   u2 minor_version() const;
 671   void set_minor_version(u2 minor_version);
 672   u2 major_version() const;
 673   void set_major_version(u2 major_version);
 674 
 675   // source debug extension
 676   const char* source_debug_extension() const { return _source_debug_extension; }
 677   void set_source_debug_extension(const char* array, int length);
 678 
 679   // nonstatic oop-map blocks
 680   static int nonstatic_oop_map_size(unsigned int oop_map_count) {
 681     return oop_map_count * OopMapBlock::size_in_words();
 682   }
 683   unsigned int nonstatic_oop_map_count() const {
 684     return _nonstatic_oop_map_size / OopMapBlock::size_in_words();
 685   }
 686   int nonstatic_oop_map_size() const { return _nonstatic_oop_map_size; }
 687   void set_nonstatic_oop_map_size(int words) {
 688     _nonstatic_oop_map_size = words;
 689   }
 690 
 691   bool has_contended_annotations() const { return _misc_flags.has_contended_annotations(); }
 692   void set_has_contended_annotations(bool value)  { _misc_flags.set_has_contended_annotations(value); }
 693 
 694 #if INCLUDE_JVMTI
 695   // Redefinition locking.  Class can only be redefined by one thread at a time.
 696   // The flag is in access_flags so that it can be set and reset using atomic
 697   // operations, and not be reset by other misc_flag settings.
 698   bool is_being_redefined() const          { return _misc_flags.is_being_redefined(); }
 699   void set_is_being_redefined(bool value)  { _misc_flags.set_is_being_redefined(value); }
 700 
 701   // RedefineClasses() support for previous versions:
 702   void add_previous_version(InstanceKlass* ik, int emcp_method_count);
 703   void purge_previous_version_list();
 704 
 705   InstanceKlass* previous_versions() const { return _previous_versions; }
 706 #else
 707   InstanceKlass* previous_versions() const { return nullptr; }
 708 #endif
 709 
 710   InstanceKlass* get_klass_version(int version);
 711 
 712   bool has_been_redefined() const { return _misc_flags.has_been_redefined(); }
 713   void set_has_been_redefined() { _misc_flags.set_has_been_redefined(true); }
 714 
 715   bool is_scratch_class() const { return _misc_flags.is_scratch_class(); }
 716   void set_is_scratch_class() { _misc_flags.set_is_scratch_class(true); }
 717 
 718   bool has_resolved_methods() const { return _misc_flags.has_resolved_methods(); }
 719   void set_has_resolved_methods()   { _misc_flags.set_has_resolved_methods(true); }
 720   void set_has_resolved_methods(bool value)   { _misc_flags.set_has_resolved_methods(value); }
 721 
 722 public:
 723 #if INCLUDE_JVMTI
 724 
 725   void init_previous_versions() {
 726     _previous_versions = nullptr;
 727   }
 728 
 729  private:
 730   static bool  _should_clean_previous_versions;
 731  public:
 732   static void purge_previous_versions(InstanceKlass* ik) {
 733     if (ik->has_been_redefined()) {
 734       ik->purge_previous_version_list();
 735     }
 736   }
 737 
 738   static bool should_clean_previous_versions_and_reset();
 739   static bool should_clean_previous_versions() { return _should_clean_previous_versions; }
 740 
 741   // JVMTI: Support for caching a class file before it is modified by an agent that can do retransformation
 742   void set_cached_class_file(JvmtiCachedClassFileData *data) {
 743     _cached_class_file = data;
 744   }
 745   JvmtiCachedClassFileData * get_cached_class_file();
 746   jint get_cached_class_file_len();
 747   unsigned char * get_cached_class_file_bytes();
 748 
 749   // JVMTI: Support for caching of field indices, types, and offsets
 750   void set_jvmti_cached_class_field_map(JvmtiCachedClassFieldMap* descriptor) {
 751     _jvmti_cached_class_field_map = descriptor;
 752   }
 753   JvmtiCachedClassFieldMap* jvmti_cached_class_field_map() const {
 754     return _jvmti_cached_class_field_map;
 755   }
 756 #else // INCLUDE_JVMTI
 757 
 758   static void purge_previous_versions(InstanceKlass* ik) { return; };
 759   static bool should_clean_previous_versions_and_reset() { return false; }
 760 
 761   void set_cached_class_file(JvmtiCachedClassFileData *data) {
 762     assert(data == nullptr, "unexpected call with JVMTI disabled");
 763   }
 764   JvmtiCachedClassFileData * get_cached_class_file() { return (JvmtiCachedClassFileData *)nullptr; }
 765 
 766 #endif // INCLUDE_JVMTI
 767 
 768   bool has_nonstatic_concrete_methods() const { return _misc_flags.has_nonstatic_concrete_methods(); }
 769   void set_has_nonstatic_concrete_methods(bool b) { _misc_flags.set_has_nonstatic_concrete_methods(b); }
 770 
 771   bool declares_nonstatic_concrete_methods() const { return _misc_flags.declares_nonstatic_concrete_methods(); }
 772   void set_declares_nonstatic_concrete_methods(bool b) { _misc_flags.set_declares_nonstatic_concrete_methods(b); }
 773 
 774   bool has_vanilla_constructor() const  { return _misc_flags.has_vanilla_constructor(); }
 775   void set_has_vanilla_constructor()    { _misc_flags.set_has_vanilla_constructor(true); }
 776   bool has_miranda_methods () const     { return _misc_flags.has_miranda_methods(); }
 777   void set_has_miranda_methods()        { _misc_flags.set_has_miranda_methods(true); }
 778   bool has_final_method() const         { return _misc_flags.has_final_method(); }
 779   void set_has_final_method()           { _misc_flags.set_has_final_method(true); }
 780 
 781   // for adding methods, ConstMethod::UNSET_IDNUM means no more ids available
 782   inline u2 next_method_idnum();
 783   void set_initial_method_idnum(u2 value)             { _idnum_allocated_count = value; }
 784 
 785   // generics support
 786   Symbol* generic_signature() const;
 787   u2 generic_signature_index() const;
 788   void set_generic_signature_index(u2 sig_index);
 789 
 790   u2 enclosing_method_data(int offset) const;
 791   u2 enclosing_method_class_index() const {
 792     return enclosing_method_data(enclosing_method_class_index_offset);
 793   }
 794   u2 enclosing_method_method_index() {
 795     return enclosing_method_data(enclosing_method_method_index_offset);
 796   }
 797   void set_enclosing_method_indices(u2 class_index,
 798                                     u2 method_index);
 799 
 800   // jmethodID support
 801   jmethodID get_jmethod_id(const methodHandle& method_h);
 802   jmethodID get_jmethod_id_fetch_or_update(size_t idnum,
 803                      jmethodID new_id, jmethodID* new_jmeths,
 804                      jmethodID* to_dealloc_id_p,
 805                      jmethodID** to_dealloc_jmeths_p);
 806   static void get_jmethod_id_length_value(jmethodID* cache, size_t idnum,
 807                 size_t *length_p, jmethodID* id_p);
 808   void ensure_space_for_methodids(int start_offset = 0);
 809   jmethodID jmethod_id_or_null(Method* method);
 810 
 811   // annotations support
 812   Annotations* annotations() const          { return _annotations; }
 813   void set_annotations(Annotations* anno)   { _annotations = anno; }
 814 
 815   AnnotationArray* class_annotations() const {
 816     return (_annotations != nullptr) ? _annotations->class_annotations() : nullptr;
 817   }
 818   Array<AnnotationArray*>* fields_annotations() const {
 819     return (_annotations != nullptr) ? _annotations->fields_annotations() : nullptr;
 820   }
 821   AnnotationArray* class_type_annotations() const {
 822     return (_annotations != nullptr) ? _annotations->class_type_annotations() : nullptr;
 823   }
 824   Array<AnnotationArray*>* fields_type_annotations() const {
 825     return (_annotations != nullptr) ? _annotations->fields_type_annotations() : nullptr;
 826   }
 827   // allocation
 828   instanceOop allocate_instance(TRAPS);
 829   static instanceOop allocate_instance(oop cls, TRAPS);
 830 
 831   // additional member function to return a handle
 832   instanceHandle allocate_instance_handle(TRAPS);
 833 
 834   objArrayOop allocate_objArray(int n, int length, TRAPS);
 835   // Helper function
 836   static instanceOop register_finalizer(instanceOop i, TRAPS);
 837 
 838   // Check whether reflection/jni/jvm code is allowed to instantiate this class;
 839   // if not, throw either an Error or an Exception.
 840   virtual void check_valid_for_instantiation(bool throwError, TRAPS);
 841 
 842   // initialization
 843   void call_class_initializer(TRAPS);
 844   void set_initialization_state_and_notify(ClassState state, JavaThread* current);
 845 
 846   // OopMapCache support
 847   OopMapCache* oop_map_cache()               { return _oop_map_cache; }
 848   void set_oop_map_cache(OopMapCache *cache) { _oop_map_cache = cache; }
 849   void mask_for(const methodHandle& method, int bci, InterpreterOopMap* entry);
 850 
 851   // JNI identifier support (for static fields - for jni performance)
 852   JNIid* jni_ids()                               { return _jni_ids; }
 853   void set_jni_ids(JNIid* ids)                   { _jni_ids = ids; }
 854   JNIid* jni_id_for(int offset);
 855 
 856   // maintenance of deoptimization dependencies
 857   inline DependencyContext dependencies();
 858   void mark_dependent_nmethods(DeoptimizationScope* deopt_scope, KlassDepChange& changes);
 859   void add_dependent_nmethod(nmethod* nm);
 860   void clean_dependency_context();
 861   // Setup link to hierarchy and deoptimize
 862   void add_to_hierarchy(JavaThread* current);
 863 
 864   // On-stack replacement support
 865   nmethod* osr_nmethods_head() const         { return _osr_nmethods_head; };
 866   void set_osr_nmethods_head(nmethod* h)     { _osr_nmethods_head = h; };
 867   void add_osr_nmethod(nmethod* n);
 868   bool remove_osr_nmethod(nmethod* n);
 869   int mark_osr_nmethods(DeoptimizationScope* deopt_scope, const Method* m);
 870   nmethod* lookup_osr_nmethod(const Method* m, int bci, int level, bool match_level) const;
 871 
 872 #if INCLUDE_JVMTI
 873   // Breakpoint support (see methods on Method* for details)
 874   BreakpointInfo* breakpoints() const       { return _breakpoints; };
 875   void set_breakpoints(BreakpointInfo* bps) { _breakpoints = bps; };
 876 #endif
 877 
 878   // support for stub routines
 879   static ByteSize init_state_offset()  { return byte_offset_of(InstanceKlass, _init_state); }
 880   JFR_ONLY(DEFINE_KLASS_TRACE_ID_OFFSET;)
 881   static ByteSize init_thread_offset() { return byte_offset_of(InstanceKlass, _init_thread); }
 882 
 883   // subclass/subinterface checks
 884   bool implements_interface(Klass* k) const;
 885   bool is_same_or_direct_interface(Klass* k) const;
 886 
 887 #ifdef ASSERT
 888   // check whether this class or one of its superclasses was redefined
 889   bool has_redefined_this_or_super() const;
 890 #endif
 891 
 892   // Access to the implementor of an interface.
 893   InstanceKlass* implementor() const;
 894   void set_implementor(InstanceKlass* ik);
 895   int  nof_implementors() const;
 896   void add_implementor(InstanceKlass* ik);  // ik is a new class that implements this interface
 897   void init_implementor();           // initialize
 898 
 899  private:
 900   // link this class into the implementors list of every interface it implements
 901   void process_interfaces();
 902 
 903  public:
 904   // virtual operations from Klass
 905   GrowableArray<Klass*>* compute_secondary_supers(int num_extra_slots,
 906                                                   Array<InstanceKlass*>* transitive_interfaces);
 907   bool can_be_primary_super_slow() const;
 908   size_t oop_size(oop obj)  const             { return size_helper(); }
 909   // slow because it's a virtual call and used for verifying the layout_helper.
 910   // Using the layout_helper bits, we can call is_instance_klass without a virtual call.
 911   DEBUG_ONLY(bool is_instance_klass_slow() const      { return true; })
 912 
 913   // Iterators
 914   void do_local_static_fields(FieldClosure* cl);
 915   void do_nonstatic_fields(FieldClosure* cl); // including inherited fields
 916   void do_local_static_fields(void f(fieldDescriptor*, Handle, TRAPS), Handle, TRAPS);
 917   void print_nonstatic_fields(FieldClosure* cl); // including inherited and injected fields
 918 
 919   void methods_do(void f(Method* method));
 920 
 921   static InstanceKlass* cast(Klass* k) {
 922     return const_cast<InstanceKlass*>(cast(const_cast<const Klass*>(k)));
 923   }
 924 
 925   static const InstanceKlass* cast(const Klass* k) {
 926     assert(k != nullptr, "k should not be null");
 927     assert(k->is_instance_klass(), "cast to InstanceKlass");
 928     return static_cast<const InstanceKlass*>(k);
 929   }
 930 
 931   virtual InstanceKlass* java_super() const {
 932     return (super() == nullptr) ? nullptr : cast(super());
 933   }
 934 
 935   // Sizing (in words)
 936   static int header_size()            { return sizeof(InstanceKlass)/wordSize; }
 937 
 938   static int size(int vtable_length, int itable_length,
 939                   int nonstatic_oop_map_size,
 940                   bool is_interface) {
 941     return align_metadata_size(header_size() +
 942            vtable_length +
 943            itable_length +
 944            nonstatic_oop_map_size +
 945            (is_interface ? (int)sizeof(Klass*)/wordSize : 0));
 946   }
 947 
 948   int size() const                    { return size(vtable_length(),
 949                                                itable_length(),
 950                                                nonstatic_oop_map_size(),
 951                                                is_interface());
 952   }
 953 
 954 
 955   inline intptr_t* start_of_itable() const;
 956   inline intptr_t* end_of_itable() const;
 957   inline oop static_field_base_raw();
 958 
 959   inline OopMapBlock* start_of_nonstatic_oop_maps() const;
 960   inline Klass** end_of_nonstatic_oop_maps() const;
 961 
 962   inline InstanceKlass* volatile* adr_implementor() const;
 963 
 964   // Use this to return the size of an instance in heap words:
 965   int size_helper() const {
 966     return layout_helper_to_size_helper(layout_helper());
 967   }
 968 
 969   // This bit is initialized in classFileParser.cpp.
 970   // It is false under any of the following conditions:
 971   //  - the class is abstract (including any interface)
 972   //  - the class has a finalizer (if !RegisterFinalizersAtInit)
 973   //  - the class size is larger than FastAllocateSizeLimit
 974   //  - the class is java/lang/Class, which cannot be allocated directly
 975   bool can_be_fastpath_allocated() const {
 976     return !layout_helper_needs_slow_path(layout_helper());
 977   }
 978 
 979   // Java itable
 980   klassItable itable() const;        // return klassItable wrapper
 981   Method* method_at_itable(InstanceKlass* holder, int index, TRAPS);
 982   Method* method_at_itable_or_null(InstanceKlass* holder, int index, bool& itable_entry_found);
 983   int vtable_index_of_interface_method(Method* method);
 984 
 985 #if INCLUDE_JVMTI
 986   void adjust_default_methods(bool* trace_name_printed);
 987 #endif // INCLUDE_JVMTI
 988 
 989   void clean_weak_instanceklass_links();
 990  private:
 991   void clean_implementors_list();
 992   void clean_method_data();
 993 
 994  public:
 995   // Explicit metaspace deallocation of fields
 996   // For RedefineClasses and class file parsing errors, we need to deallocate
 997   // instanceKlasses and the metadata they point to.
 998   void deallocate_contents(ClassLoaderData* loader_data);
 999   static void deallocate_methods(ClassLoaderData* loader_data,
1000                                  Array<Method*>* methods);
1001   void static deallocate_interfaces(ClassLoaderData* loader_data,
1002                                     const Klass* super_klass,
1003                                     Array<InstanceKlass*>* local_interfaces,
1004                                     Array<InstanceKlass*>* transitive_interfaces);
1005   void static deallocate_record_components(ClassLoaderData* loader_data,
1006                                            Array<RecordComponent*>* record_component);
1007 
1008   virtual bool on_stack() const;
1009 
1010   // callbacks for actions during class unloading
1011   static void unload_class(InstanceKlass* ik);
1012 
1013   virtual void release_C_heap_structures(bool release_sub_metadata = true);
1014 
1015   // Naming
1016   const char* signature_name() const;
1017 
1018   // Oop fields (and metadata) iterators
1019   //
1020   // The InstanceKlass iterators also visits the Object's klass.
1021 
1022   // Forward iteration
1023  public:
1024   // Iterate over all oop fields in the oop maps.
1025   template <typename T, class OopClosureType>
1026   inline void oop_oop_iterate_oop_maps(oop obj, OopClosureType* closure);
1027 
1028   // Iterate over all oop fields and metadata.
1029   template <typename T, class OopClosureType>
1030   inline void oop_oop_iterate(oop obj, OopClosureType* closure);
1031 
1032   // Iterate over all oop fields in one oop map.
1033   template <typename T, class OopClosureType>
1034   inline void oop_oop_iterate_oop_map(OopMapBlock* map, oop obj, OopClosureType* closure);
1035 
1036 
1037   // Reverse iteration
1038   // Iterate over all oop fields and metadata.
1039   template <typename T, class OopClosureType>
1040   inline void oop_oop_iterate_reverse(oop obj, OopClosureType* closure);
1041 
1042  private:
1043   // Iterate over all oop fields in the oop maps.
1044   template <typename T, class OopClosureType>
1045   inline void oop_oop_iterate_oop_maps_reverse(oop obj, OopClosureType* closure);
1046 
1047   // Iterate over all oop fields in one oop map.
1048   template <typename T, class OopClosureType>
1049   inline void oop_oop_iterate_oop_map_reverse(OopMapBlock* map, oop obj, OopClosureType* closure);
1050 
1051 
1052   // Bounded range iteration
1053  public:
1054   // Iterate over all oop fields in the oop maps.
1055   template <typename T, class OopClosureType>
1056   inline void oop_oop_iterate_oop_maps_bounded(oop obj, OopClosureType* closure, MemRegion mr);
1057 
1058   // Iterate over all oop fields and metadata.
1059   template <typename T, class OopClosureType>
1060   inline void oop_oop_iterate_bounded(oop obj, OopClosureType* closure, MemRegion mr);
1061 
1062  private:
1063   // Iterate over all oop fields in one oop map.
1064   template <typename T, class OopClosureType>
1065   inline void oop_oop_iterate_oop_map_bounded(OopMapBlock* map, oop obj, OopClosureType* closure, MemRegion mr);
1066 
1067 
1068  public:
1069   u2 idnum_allocated_count() const      { return _idnum_allocated_count; }
1070 
1071  private:
1072   // initialization state
1073   void set_init_state(ClassState state);
1074   void set_rewritten()                  { _misc_flags.set_rewritten(true); }
1075   void set_init_thread(JavaThread *thread)  {
1076     assert((thread == JavaThread::current() && _init_thread == nullptr) ||
1077            (thread == nullptr && _init_thread == JavaThread::current()), "Only one thread is allowed to own initialization");
1078     Atomic::store(&_init_thread, thread);
1079   }
1080 
1081   // The RedefineClasses() API can cause new method idnums to be needed
1082   // which will cause the caches to grow. Safety requires different
1083   // cache management logic if the caches can grow instead of just
1084   // going from null to non-null.
1085   bool idnum_can_increment() const      { return has_been_redefined(); }
1086   inline jmethodID* methods_jmethod_ids_acquire() const;
1087   inline void release_set_methods_jmethod_ids(jmethodID* jmeths);
1088   // This nulls out jmethodIDs for all methods in 'klass'
1089   static void clear_jmethod_ids(InstanceKlass* klass);
1090 
1091   // Lock during initialization
1092 public:
1093   // Returns the array class for the n'th dimension
1094   virtual ArrayKlass* array_klass(int n, TRAPS);
1095   virtual ArrayKlass* array_klass_or_null(int n);
1096 
1097   // Returns the array class with this class as element type
1098   virtual ArrayKlass* array_klass(TRAPS);
1099   virtual ArrayKlass* array_klass_or_null();
1100 
1101   static void clean_initialization_error_table();
1102 
1103   Monitor* init_monitor() const { return _init_monitor; }
1104 private:
1105   void check_link_state_and_wait(JavaThread* current);
1106   bool link_class_impl                           (TRAPS);
1107   bool verify_code                               (TRAPS);
1108   void initialize_impl                           (TRAPS);
1109   void initialize_super_interfaces               (TRAPS);
1110 
1111   void add_initialization_error(JavaThread* current, Handle exception);
1112   oop get_initialization_error(JavaThread* current);
1113 
1114   // find a local method (returns null if not found)
1115   Method* find_method_impl(const Symbol* name,
1116                            const Symbol* signature,
1117                            OverpassLookupMode overpass_mode,
1118                            StaticLookupMode static_mode,
1119                            PrivateLookupMode private_mode) const;
1120 
1121   static Method* find_method_impl(const Array<Method*>* methods,
1122                                   const Symbol* name,
1123                                   const Symbol* signature,
1124                                   OverpassLookupMode overpass_mode,
1125                                   StaticLookupMode static_mode,
1126                                   PrivateLookupMode private_mode);
1127 
1128 #if INCLUDE_JVMTI
1129   // RedefineClasses support
1130   void link_previous_versions(InstanceKlass* pv) { _previous_versions = pv; }
1131   void mark_newly_obsolete_methods(Array<Method*>* old_methods, int emcp_method_count);
1132 #endif
1133   // log class name to classlist
1134   void log_to_classlist() const;
1135 public:
1136 
1137 #if INCLUDE_CDS
1138   // CDS support - remove and restore oops from metadata. Oops are not shared.
1139   virtual void remove_unshareable_info();
1140   void remove_unshareable_flags();
1141   virtual void remove_java_mirror();
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   bool methods_contain_jsr_bytecode() const;
1146   void compute_has_loops_flag_for_methods();
1147 #endif
1148 
1149   jint compute_modifier_flags() const;
1150 
1151 public:
1152   // JVMTI support
1153   jint jvmti_class_status() const;
1154 
1155   virtual void metaspace_pointers_do(MetaspaceClosure* iter);
1156 
1157  public:
1158   // Printing
1159   void print_on(outputStream* st) const;
1160   void print_value_on(outputStream* st) const;
1161 
1162   void oop_print_value_on(oop obj, outputStream* st);
1163 
1164   void oop_print_on      (oop obj, outputStream* st);
1165 
1166 #ifndef PRODUCT
1167   void print_dependent_nmethods(bool verbose = false);
1168   bool is_dependent_nmethod(nmethod* nm);
1169   bool verify_itable_index(int index);
1170 #endif
1171 
1172   const char* internal_name() const;
1173 
1174   // Verification
1175   void verify_on(outputStream* st);
1176 
1177   void oop_verify_on(oop obj, outputStream* st);
1178 
1179   // Logging
1180   void print_class_load_logging(ClassLoaderData* loader_data,
1181                                 const ModuleEntry* module_entry,
1182                                 const ClassFileStream* cfs) const;
1183  private:
1184   void print_class_load_cause_logging() const;
1185   void print_class_load_helper(ClassLoaderData* loader_data,
1186                                const ModuleEntry* module_entry,
1187                                const ClassFileStream* cfs) const;
1188 };
1189 
1190 // for adding methods
1191 // UNSET_IDNUM return means no more ids available
1192 inline u2 InstanceKlass::next_method_idnum() {
1193   if (_idnum_allocated_count == ConstMethod::MAX_IDNUM) {
1194     return ConstMethod::UNSET_IDNUM; // no more ids available
1195   } else {
1196     return _idnum_allocated_count++;
1197   }
1198 }
1199 
1200 class PrintClassClosure : public KlassClosure {
1201 private:
1202   outputStream* _st;
1203   bool _verbose;
1204 public:
1205   PrintClassClosure(outputStream* st, bool verbose);
1206 
1207   void do_klass(Klass* k);
1208 };
1209 
1210 /* JNIid class for jfieldIDs only */
1211 class JNIid: public CHeapObj<mtClass> {
1212   friend class VMStructs;
1213  private:
1214   Klass*             _holder;
1215   JNIid*             _next;
1216   int                _offset;
1217 #ifdef ASSERT
1218   bool               _is_static_field_id;
1219 #endif
1220 
1221  public:
1222   // Accessors
1223   Klass* holder() const           { return _holder; }
1224   int offset() const              { return _offset; }
1225   JNIid* next()                   { return _next; }
1226   // Constructor
1227   JNIid(Klass* holder, int offset, JNIid* next);
1228   // Identifier lookup
1229   JNIid* find(int offset);
1230 
1231   bool find_local_field(fieldDescriptor* fd) {
1232     return InstanceKlass::cast(holder())->find_local_field_from_offset(offset(), true, fd);
1233   }
1234 
1235   static void deallocate(JNIid* id);
1236   // Debugging
1237 #ifdef ASSERT
1238   bool is_static_field_id() const { return _is_static_field_id; }
1239   void set_is_static_field_id()   { _is_static_field_id = true; }
1240 #endif
1241   void verify(Klass* holder);
1242 };
1243 
1244 // An iterator that's used to access the inner classes indices in the
1245 // InstanceKlass::_inner_classes array.
1246 class InnerClassesIterator : public StackObj {
1247  private:
1248   Array<jushort>* _inner_classes;
1249   int _length;
1250   int _idx;
1251  public:
1252 
1253   InnerClassesIterator(const InstanceKlass* k) {
1254     _inner_classes = k->inner_classes();
1255     if (k->inner_classes() != nullptr) {
1256       _length = _inner_classes->length();
1257       // The inner class array's length should be the multiple of
1258       // inner_class_next_offset if it only contains the InnerClasses
1259       // attribute data, or it should be
1260       // n*inner_class_next_offset+enclosing_method_attribute_size
1261       // if it also contains the EnclosingMethod data.
1262       assert((_length % InstanceKlass::inner_class_next_offset == 0 ||
1263               _length % InstanceKlass::inner_class_next_offset == InstanceKlass::enclosing_method_attribute_size),
1264              "just checking");
1265       // Remove the enclosing_method portion if exists.
1266       if (_length % InstanceKlass::inner_class_next_offset == InstanceKlass::enclosing_method_attribute_size) {
1267         _length -= InstanceKlass::enclosing_method_attribute_size;
1268       }
1269     } else {
1270       _length = 0;
1271     }
1272     _idx = 0;
1273   }
1274 
1275   int length() const {
1276     return _length;
1277   }
1278 
1279   void next() {
1280     _idx += InstanceKlass::inner_class_next_offset;
1281   }
1282 
1283   bool done() const {
1284     return (_idx >= _length);
1285   }
1286 
1287   u2 inner_class_info_index() const {
1288     return _inner_classes->at(
1289                _idx + InstanceKlass::inner_class_inner_class_info_offset);
1290   }
1291 
1292   void set_inner_class_info_index(u2 index) {
1293     _inner_classes->at_put(
1294                _idx + InstanceKlass::inner_class_inner_class_info_offset, index);
1295   }
1296 
1297   u2 outer_class_info_index() const {
1298     return _inner_classes->at(
1299                _idx + InstanceKlass::inner_class_outer_class_info_offset);
1300   }
1301 
1302   void set_outer_class_info_index(u2 index) {
1303     _inner_classes->at_put(
1304                _idx + InstanceKlass::inner_class_outer_class_info_offset, index);
1305   }
1306 
1307   u2 inner_name_index() const {
1308     return _inner_classes->at(
1309                _idx + InstanceKlass::inner_class_inner_name_offset);
1310   }
1311 
1312   void set_inner_name_index(u2 index) {
1313     _inner_classes->at_put(
1314                _idx + InstanceKlass::inner_class_inner_name_offset, index);
1315   }
1316 
1317   u2 inner_access_flags() const {
1318     return _inner_classes->at(
1319                _idx + InstanceKlass::inner_class_access_flags_offset);
1320   }
1321 };
1322 
1323 // Iterator over class hierarchy under a particular class. Implements depth-first pre-order traversal.
1324 // Usage:
1325 //  for (ClassHierarchyIterator iter(root_klass); !iter.done(); iter.next()) {
1326 //    Klass* k = iter.klass();
1327 //    ...
1328 //  }
1329 class ClassHierarchyIterator : public StackObj {
1330  private:
1331   InstanceKlass* _root;
1332   Klass*         _current;
1333   bool           _visit_subclasses;
1334 
1335  public:
1336   ClassHierarchyIterator(InstanceKlass* root) : _root(root), _current(root), _visit_subclasses(true) {
1337     assert(_root == _current, "required"); // initial state
1338   }
1339 
1340   bool done() {
1341     return (_current == nullptr);
1342   }
1343 
1344   // Make a step iterating over the class hierarchy under the root class.
1345   // Skips subclasses if requested.
1346   void next();
1347 
1348   Klass* klass() {
1349     assert(!done(), "sanity");
1350     return _current;
1351   }
1352 
1353   // Skip subclasses of the current class.
1354   void skip_subclasses() {
1355     _visit_subclasses = false;
1356   }
1357 };
1358 
1359 #endif // SHARE_OOPS_INSTANCEKLASS_HPP