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 "code/vmreg.hpp"
  29 #include "memory/referenceType.hpp"
  30 #include "oops/annotations.hpp"
  31 #include "oops/constMethod.hpp"
  32 #include "oops/constantPool.hpp"
  33 #include "oops/fieldInfo.hpp"
  34 #include "oops/instanceKlassFlags.hpp"
  35 #include "oops/instanceOop.hpp"
  36 #include "runtime/handles.hpp"
  37 #include "utilities/accessFlags.hpp"
  38 #include "utilities/align.hpp"
  39 #include "utilities/macros.hpp"
  40 #if INCLUDE_JFR
  41 #include "jfr/support/jfrKlassExtension.hpp"
  42 #endif
  43 
  44 class DeoptimizationScope;
  45 class klassItable;
  46 class RecordComponent;
  47 
  48 // An InstanceKlass is the VM level representation of a Java class.
  49 // It contains all information needed for at class at execution runtime.
  50 
  51 //  InstanceKlass embedded field layout (after declared fields):
  52 //    [EMBEDDED Java vtable             ] size in words = vtable_len
  53 //    [EMBEDDED nonstatic oop-map blocks] size in words = nonstatic_oop_map_size
  54 //      The embedded nonstatic oop-map blocks are short pairs (offset, length)
  55 //      indicating where oops are located in instances of this klass.
  56 //    [EMBEDDED implementor of the interface] only exist for interface
  57 //    [EMBEDDED inline_type_field_klasses] only if has_inline_fields() == true
  58 //    [EMBEDDED InlineKlassFixedBlock] only if is an InlineKlass instance
  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 BufferedInlineTypeBlob;
  76 class InterpreterOopMap;
  77 class PackageEntry;
  78 class ModuleEntry;
  79 
  80 // This is used in iterators below.
  81 class FieldClosure: public StackObj {
  82 public:
  83   virtual void do_field(fieldDescriptor* fd) = 0;
  84 };
  85 
  86 // Print fields.
  87 // If "obj" argument to constructor is null, prints static fields, otherwise prints non-static fields.
  88 class FieldPrinter: public FieldClosure {
  89    oop _obj;
  90    outputStream* _st;
  91  public:
  92    FieldPrinter(outputStream* st, oop obj = nullptr) : _obj(obj), _st(st) {}
  93    void do_field(fieldDescriptor* fd);
  94 };
  95 
  96 // Describes where oops are located in instances of this klass.
  97 class OopMapBlock {
  98  public:
  99   // Byte offset of the first oop mapped by this block.
 100   int offset() const          { return _offset; }
 101   void set_offset(int offset) { _offset = offset; }
 102 
 103   // Number of oops in this block.
 104   uint count() const         { return _count; }
 105   void set_count(uint count) { _count = count; }
 106 
 107   void increment_count(int diff) { _count += diff; }
 108 
 109   int offset_span() const { return _count * heapOopSize; }
 110 
 111   int end_offset() const {
 112     return offset() + offset_span();
 113   }
 114 
 115   bool is_contiguous(int another_offset) const {
 116     return another_offset == end_offset();
 117   }
 118 
 119   // sizeof(OopMapBlock) in words.
 120   static const int size_in_words() {
 121     return align_up((int)sizeof(OopMapBlock), wordSize) >>
 122       LogBytesPerWord;
 123   }
 124 
 125   static int compare_offset(const OopMapBlock* a, const OopMapBlock* b) {
 126     return a->offset() - b->offset();
 127   }
 128 
 129  private:
 130   int  _offset;
 131   uint _count;
 132 };
 133 
 134 struct JvmtiCachedClassFileData;
 135 
 136 class SigEntry;
 137 
 138 class InlineKlassFixedBlock {
 139   Array<SigEntry>** _extended_sig;
 140   Array<VMRegPair>** _return_regs;
 141   address* _pack_handler;
 142   address* _pack_handler_jobject;
 143   address* _unpack_handler;
 144   int* _default_value_offset;
 145   ArrayKlass** _null_free_inline_array_klasses;
 146   int _alignment;
 147   int _first_field_offset;
 148   int _exact_size_in_bytes;
 149 
 150   friend class InlineKlass;
 151 };
 152 
 153 class InstanceKlass: public Klass {
 154   friend class VMStructs;
 155   friend class JVMCIVMStructs;
 156   friend class ClassFileParser;
 157   friend class CompileReplay;
 158   friend class TemplateTable;
 159 
 160  public:
 161   static const KlassKind Kind = InstanceKlassKind;
 162 
 163  protected:
 164   InstanceKlass(const ClassFileParser& parser, KlassKind kind = Kind, ReferenceType reference_type = REF_NONE);
 165 
 166  public:
 167   InstanceKlass() { assert(DumpSharedSpaces || UseSharedSpaces, "only for CDS"); }
 168 
 169   // See "The Java Virtual Machine Specification" section 2.16.2-5 for a detailed description
 170   // of the class loading & initialization procedure, and the use of the states.
 171   enum ClassState : u1 {
 172     allocated,                          // allocated (but not yet linked)
 173     loaded,                             // loaded and inserted in class hierarchy (but not linked yet)
 174     being_linked,                       // currently running verifier and rewriter
 175     linked,                             // successfully linked/verified (but not initialized yet)
 176     being_initialized,                  // currently running class initializer
 177     fully_initialized,                  // initialized (successful final state)
 178     initialization_error                // error happened during initialization
 179   };
 180 
 181  private:
 182   static InstanceKlass* allocate_instance_klass(const ClassFileParser& parser, TRAPS);
 183 
 184  protected:
 185   // If you add a new field that points to any metaspace object, you
 186   // must add this field to InstanceKlass::metaspace_pointers_do().
 187 
 188   // Annotations for this class
 189   Annotations*    _annotations;
 190   // Package this class is defined in
 191   PackageEntry*   _package_entry;
 192   // Array classes holding elements of this class.
 193   ArrayKlass* volatile _array_klasses;
 194   // Constant pool for this class.
 195   ConstantPool* _constants;
 196   // The InnerClasses attribute and EnclosingMethod attribute. The
 197   // _inner_classes is an array of shorts. If the class has InnerClasses
 198   // attribute, then the _inner_classes array begins with 4-tuples of shorts
 199   // [inner_class_info_index, outer_class_info_index,
 200   // inner_name_index, inner_class_access_flags] for the InnerClasses
 201   // attribute. If the EnclosingMethod attribute exists, it occupies the
 202   // last two shorts [class_index, method_index] of the array. If only
 203   // the InnerClasses attribute exists, the _inner_classes array length is
 204   // number_of_inner_classes * 4. If the class has both InnerClasses
 205   // and EnclosingMethod attributes the _inner_classes array length is
 206   // number_of_inner_classes * 4 + enclosing_method_attribute_size.
 207   Array<jushort>* _inner_classes;
 208 
 209   // The NestMembers attribute. An array of shorts, where each is a
 210   // class info index for the class that is a nest member. This data
 211   // has not been validated.
 212   Array<jushort>* _nest_members;
 213 
 214   // Resolved nest-host klass: either true nest-host or self if we are not
 215   // nested, or an error occurred resolving or validating the nominated
 216   // nest-host. Can also be set directly by JDK API's that establish nest
 217   // relationships.
 218   // By always being set it makes nest-member access checks simpler.
 219   InstanceKlass* _nest_host;
 220 
 221   // The PermittedSubclasses attribute. An array of shorts, where each is a
 222   // class info index for the class that is a permitted subclass.
 223   Array<jushort>* _permitted_subclasses;
 224 
 225   // The contents of the Record attribute.
 226   Array<RecordComponent*>* _record_components;
 227 
 228   // the source debug extension for this klass, null if not specified.
 229   // Specified as UTF-8 string without terminating zero byte in the classfile,
 230   // it is stored in the instanceklass as a null-terminated UTF-8 string
 231   const char*     _source_debug_extension;
 232 
 233   // Number of heapOopSize words used by non-static fields in this klass
 234   // (including inherited fields but after header_size()).
 235   int             _nonstatic_field_size;
 236   int             _static_field_size;       // number words used by static fields (oop and non-oop) in this klass
 237   int             _nonstatic_oop_map_size;  // size in words of nonstatic oop map blocks
 238   int             _itable_len;              // length of Java itable (in words)
 239 
 240   // The NestHost attribute. The class info index for the class
 241   // that is the nest-host of this class. This data has not been validated.
 242   u2              _nest_host_index;
 243   u2              _this_class_index;        // constant pool entry
 244   u2              _static_oop_field_count;  // number of static oop fields in this klass
 245 
 246   volatile u2     _idnum_allocated_count;   // JNI/JVMTI: increments with the addition of methods, old ids don't change
 247 
 248   volatile ClassState _init_state;          // state of class
 249 
 250   u1              _reference_type;          // reference type
 251 
 252   // State is set either at parse time or while executing, atomically to not disturb other state
 253   InstanceKlassFlags _misc_flags;
 254 
 255   Monitor*             _init_monitor;       // mutual exclusion to _init_state and _init_thread.
 256   JavaThread* volatile _init_thread;        // Pointer to current thread doing initialization (to handle recursive initialization)
 257 
 258   OopMapCache*    volatile _oop_map_cache;   // OopMapCache for all methods in the klass (allocated lazily)
 259   JNIid*          _jni_ids;              // First JNI identifier for static fields in this class
 260   jmethodID*      volatile _methods_jmethod_ids;  // jmethodIDs corresponding to method_idnum, or null if none
 261   nmethodBucket*  volatile _dep_context;          // packed DependencyContext structure
 262   uint64_t        volatile _dep_context_last_cleaned;
 263   nmethod*        _osr_nmethods_head;    // Head of list of on-stack replacement nmethods for this class
 264 #if INCLUDE_JVMTI
 265   BreakpointInfo* _breakpoints;          // bpt lists, managed by Method*
 266   // Linked instanceKlasses of previous versions
 267   InstanceKlass* _previous_versions;
 268   // JVMTI fields can be moved to their own structure - see 6315920
 269   // JVMTI: cached class file, before retransformable agent modified it in CFLH
 270   JvmtiCachedClassFileData* _cached_class_file;
 271 #endif
 272 
 273 #if INCLUDE_JVMTI
 274   JvmtiCachedClassFieldMap* _jvmti_cached_class_field_map;  // JVMTI: used during heap iteration
 275 #endif
 276 
 277   NOT_PRODUCT(int _verify_count;)  // to avoid redundant verifies
 278   NOT_PRODUCT(volatile int _shared_class_load_count;) // ensure a shared class is loaded only once
 279 
 280   // Method array.
 281   Array<Method*>* _methods;
 282   // Default Method Array, concrete methods inherited from interfaces
 283   Array<Method*>* _default_methods;
 284   // Interfaces (InstanceKlass*s) this class declares locally to implement.
 285   Array<InstanceKlass*>* _local_interfaces;
 286   // Interfaces (InstanceKlass*s) this class implements transitively.
 287   Array<InstanceKlass*>* _transitive_interfaces;
 288   // Int array containing the original order of method in the class file (for JVMTI).
 289   Array<int>*     _method_ordering;
 290   // Int array containing the vtable_indices for default_methods
 291   // offset matches _default_methods offset
 292   Array<int>*     _default_vtable_indices;
 293 
 294   // Fields information is stored in an UNSIGNED5 encoded stream (see fieldInfo.hpp)
 295   Array<u1>*          _fieldinfo_stream;
 296   Array<FieldStatus>* _fields_status;
 297 
 298   const Klass**   _inline_type_field_klasses; // For "inline class" fields, NULL if none present
 299   Array<u2>* _preload_classes;
 300   const InlineKlassFixedBlock* _adr_inlineklass_fixed_block;
 301 
 302   // embedded Java vtable follows here
 303   // embedded Java itables follows here
 304   // embedded static fields follows here
 305   // embedded nonstatic oop-map blocks follows here
 306   // embedded implementor of this interface follows here
 307   //   The embedded implementor only exists if the current klass is an
 308   //   interface. The possible values of the implementor fall into following
 309   //   three cases:
 310   //     null: no implementor.
 311   //     A Klass* that's not itself: one implementor.
 312   //     Itself: more than one implementors.
 313   //
 314 
 315   friend class SystemDictionary;
 316 
 317   static bool _disable_method_binary_search;
 318 
 319   // Controls finalizer registration
 320   static bool _finalization_enabled;
 321 
 322  public:
 323 
 324   // Queries finalization state
 325   static bool is_finalization_enabled() { return _finalization_enabled; }
 326 
 327   // Sets finalization state
 328   static void set_finalization_enabled(bool val) { _finalization_enabled = val; }
 329 
 330   // The three BUILTIN class loader types
 331   bool is_shared_boot_class() const { return _misc_flags.is_shared_boot_class(); }
 332   bool is_shared_platform_class() const { return _misc_flags.is_shared_platform_class(); }
 333   bool is_shared_app_class() const {  return _misc_flags.is_shared_app_class(); }
 334   // The UNREGISTERED class loader type
 335   bool is_shared_unregistered_class() const { return _misc_flags.is_shared_unregistered_class(); }
 336 
 337   // Check if the class can be shared in CDS
 338   bool is_shareable() const;
 339 
 340   bool shared_loading_failed() const { return _misc_flags.shared_loading_failed(); }
 341 
 342   void set_shared_loading_failed() { _misc_flags.set_shared_loading_failed(true); }
 343 
 344 #if INCLUDE_CDS
 345   void set_shared_class_loader_type(s2 loader_type) { _misc_flags.set_shared_class_loader_type(loader_type); }
 346   void assign_class_loader_type() { _misc_flags.assign_class_loader_type(_class_loader_data); }
 347 #endif
 348 
 349   bool has_nonstatic_fields() const        { return _misc_flags.has_nonstatic_fields(); }
 350   void set_has_nonstatic_fields(bool b)    { _misc_flags.set_has_nonstatic_fields(b); }
 351 
 352   bool has_localvariable_table() const     { return _misc_flags.has_localvariable_table(); }
 353   void set_has_localvariable_table(bool b) { _misc_flags.set_has_localvariable_table(b); }
 354 
 355   bool has_inline_type_fields() const { return _misc_flags.has_inline_type_fields(); }
 356   void set_has_inline_type_fields()   { _misc_flags.set_has_inline_type_fields(true); }
 357 
 358   bool is_empty_inline_type() const   { return _misc_flags.is_empty_inline_type(); }
 359   void set_is_empty_inline_type()     { _misc_flags.set_is_empty_inline_type(true); }
 360 
 361   // Note:  The naturally_atomic property only applies to
 362   // inline classes; it is never true on identity classes.
 363   // The bit is placed on instanceKlass for convenience.
 364 
 365   // Query if h/w provides atomic load/store for instances.
 366   bool is_naturally_atomic() const  { return _misc_flags.is_naturally_atomic(); }
 367   void set_is_naturally_atomic()    { _misc_flags.set_is_naturally_atomic(true); }
 368 
 369   // Query if this class implements jl.NonTearable or was
 370   // mentioned in the JVM option ForceNonTearable.
 371   // This bit can occur anywhere, but is only significant
 372   // for inline classes *and* their super types.
 373   // It inherits from supers along with NonTearable.
 374   bool is_declared_atomic() const { return _misc_flags.is_declared_atomic(); }
 375   void set_is_declared_atomic()   { _misc_flags.set_is_declared_atomic(true); }
 376 
 377   bool carries_value_modifier() const { return _misc_flags.carries_value_modifier(); }
 378   void set_carries_value_modifier()   { _misc_flags.set_carries_value_modifier(true); }
 379 
 380   bool carries_identity_modifier() const  { return _misc_flags.carries_identity_modifier(); }
 381   void set_carries_identity_modifier()    { _misc_flags.set_carries_identity_modifier(true); }
 382 
 383   // field sizes
 384   int nonstatic_field_size() const         { return _nonstatic_field_size; }
 385   void set_nonstatic_field_size(int size)  { _nonstatic_field_size = size; }
 386 
 387   int static_field_size() const            { return _static_field_size; }
 388   void set_static_field_size(int size)     { _static_field_size = size; }
 389 
 390   int static_oop_field_count() const       { return (int)_static_oop_field_count; }
 391   void set_static_oop_field_count(u2 size) { _static_oop_field_count = size; }
 392 
 393   // Java itable
 394   int  itable_length() const               { return _itable_len; }
 395   void set_itable_length(int len)          { _itable_len = len; }
 396 
 397   // array klasses
 398   ArrayKlass* array_klasses() const     { return _array_klasses; }
 399   inline ArrayKlass* array_klasses_acquire() const; // load with acquire semantics
 400   inline void release_set_array_klasses(ArrayKlass* k); // store with release semantics
 401 
 402   // methods
 403   Array<Method*>* methods() const          { return _methods; }
 404   void set_methods(Array<Method*>* a)      { _methods = a; }
 405   Method* method_with_idnum(int idnum);
 406   Method* method_with_orig_idnum(int idnum);
 407   Method* method_with_orig_idnum(int idnum, int version);
 408 
 409   // method ordering
 410   Array<int>* method_ordering() const     { return _method_ordering; }
 411   void set_method_ordering(Array<int>* m) { _method_ordering = m; }
 412   void copy_method_ordering(const intArray* m, TRAPS);
 413 
 414   // default_methods
 415   Array<Method*>* default_methods() const  { return _default_methods; }
 416   void set_default_methods(Array<Method*>* a) { _default_methods = a; }
 417 
 418   // default method vtable_indices
 419   Array<int>* default_vtable_indices() const { return _default_vtable_indices; }
 420   void set_default_vtable_indices(Array<int>* v) { _default_vtable_indices = v; }
 421   Array<int>* create_new_default_vtable_indices(int len, TRAPS);
 422 
 423   // interfaces
 424   Array<InstanceKlass*>* local_interfaces() const          { return _local_interfaces; }
 425   void set_local_interfaces(Array<InstanceKlass*>* a)      {
 426     guarantee(_local_interfaces == nullptr || a == nullptr, "Just checking");
 427     _local_interfaces = a; }
 428 
 429   Array<InstanceKlass*>* transitive_interfaces() const     { return _transitive_interfaces; }
 430   void set_transitive_interfaces(Array<InstanceKlass*>* a) {
 431     guarantee(_transitive_interfaces == nullptr || a == nullptr, "Just checking");
 432     _transitive_interfaces = a;
 433   }
 434 
 435  private:
 436   friend class fieldDescriptor;
 437   FieldInfo field(int index) const;
 438 
 439  public:
 440   int     field_offset      (int index) const { return field(index).offset(); }
 441   int     field_access_flags(int index) const { return field(index).access_flags().as_int(); }
 442   FieldInfo::FieldFlags field_flags(int index) const { return field(index).field_flags(); }
 443   FieldStatus field_status(int index)   const { return fields_status()->at(index); }
 444   inline Symbol* field_name        (int index) const;
 445   inline Symbol* field_signature   (int index) const;
 446   bool    field_is_inlined(int index) const { return field_flags(index).is_inlined(); }
 447   bool    field_is_null_free_inline_type(int index) const;
 448 
 449   // Number of Java declared fields
 450   int java_fields_count() const;
 451   int total_fields_count() const;
 452 
 453   Array<u1>* fieldinfo_stream() const { return _fieldinfo_stream; }
 454   void set_fieldinfo_stream(Array<u1>* fis) { _fieldinfo_stream = fis; }
 455 
 456   Array<FieldStatus>* fields_status() const {return _fields_status; }
 457   void set_fields_status(Array<FieldStatus>* array) { _fields_status = array; }
 458 
 459   Array<u2>* preload_classes() const { return _preload_classes; }
 460   void set_preload_classes(Array<u2>* c) { _preload_classes = c; }
 461 
 462   // inner classes
 463   Array<u2>* inner_classes() const       { return _inner_classes; }
 464   void set_inner_classes(Array<u2>* f)   { _inner_classes = f; }
 465 
 466   // nest members
 467   Array<u2>* nest_members() const     { return _nest_members; }
 468   void set_nest_members(Array<u2>* m) { _nest_members = m; }
 469 
 470   // nest-host index
 471   jushort nest_host_index() const { return _nest_host_index; }
 472   void set_nest_host_index(u2 i)  { _nest_host_index = i; }
 473   // dynamic nest member support
 474   void set_nest_host(InstanceKlass* host);
 475 
 476   // record components
 477   Array<RecordComponent*>* record_components() const { return _record_components; }
 478   void set_record_components(Array<RecordComponent*>* record_components) {
 479     _record_components = record_components;
 480   }
 481   bool is_record() const;
 482 
 483   // permitted subclasses
 484   Array<u2>* permitted_subclasses() const     { return _permitted_subclasses; }
 485   void set_permitted_subclasses(Array<u2>* s) { _permitted_subclasses = s; }
 486 
 487 private:
 488   // Called to verify that k is a member of this nest - does not look at k's nest-host,
 489   // nor does it resolve any CP entries or load any classes.
 490   bool has_nest_member(JavaThread* current, InstanceKlass* k) const;
 491 
 492 public:
 493   // Call this only if you know that the nest host has been initialized.
 494   InstanceKlass* nest_host_not_null() {
 495     assert(_nest_host != nullptr, "must be");
 496     return _nest_host;
 497   }
 498   // Used to construct informative IllegalAccessError messages at a higher level,
 499   // if there was an issue resolving or validating the nest host.
 500   // Returns null if there was no error.
 501   const char* nest_host_error();
 502   // Returns nest-host class, resolving and validating it if needed.
 503   // Returns null if resolution is not possible from the calling context.
 504   InstanceKlass* nest_host(TRAPS);
 505   // Check if this klass is a nestmate of k - resolves this nest-host and k's
 506   bool has_nestmate_access_to(InstanceKlass* k, TRAPS);
 507 
 508   // Called to verify that k is a permitted subclass of this class
 509   bool has_as_permitted_subclass(const InstanceKlass* k) const;
 510 
 511   enum InnerClassAttributeOffset {
 512     // From http://mirror.eng/products/jdk/1.1/docs/guide/innerclasses/spec/innerclasses.doc10.html#18814
 513     inner_class_inner_class_info_offset = 0,
 514     inner_class_outer_class_info_offset = 1,
 515     inner_class_inner_name_offset = 2,
 516     inner_class_access_flags_offset = 3,
 517     inner_class_next_offset = 4
 518   };
 519 
 520   enum EnclosingMethodAttributeOffset {
 521     enclosing_method_class_index_offset = 0,
 522     enclosing_method_method_index_offset = 1,
 523     enclosing_method_attribute_size = 2
 524   };
 525 
 526   // package
 527   PackageEntry* package() const     { return _package_entry; }
 528   ModuleEntry* module() const;
 529   bool in_unnamed_package() const   { return (_package_entry == nullptr); }
 530   void set_package(ClassLoaderData* loader_data, PackageEntry* pkg_entry, TRAPS);
 531   // If the package for the InstanceKlass is in the boot loader's package entry
 532   // table then sets the classpath_index field so that
 533   // get_system_package() will know to return a non-null value for the
 534   // package's location.  And, so that the package will be added to the list of
 535   // packages returned by get_system_packages().
 536   // For packages whose classes are loaded from the boot loader class path, the
 537   // classpath_index indicates which entry on the boot loader class path.
 538   void set_classpath_index(s2 path_index);
 539   bool is_same_class_package(const Klass* class2) const;
 540   bool is_same_class_package(oop other_class_loader, const Symbol* other_class_name) const;
 541 
 542   // find an enclosing class
 543   InstanceKlass* compute_enclosing_class(bool* inner_is_member, TRAPS) const;
 544 
 545   // Find InnerClasses attribute and return outer_class_info_index & inner_name_index.
 546   bool find_inner_classes_attr(int* ooff, int* noff, TRAPS) const;
 547 
 548  private:
 549   // Check prohibited package ("java/" only loadable by boot or platform loaders)
 550   static void check_prohibited_package(Symbol* class_name,
 551                                        ClassLoaderData* loader_data,
 552                                        TRAPS);
 553  public:
 554   // initialization state
 555   bool is_loaded() const                   { return init_state() >= loaded; }
 556   bool is_linked() const                   { return init_state() >= linked; }
 557   bool is_being_linked() const             { return init_state() == being_linked; }
 558   bool is_initialized() const              { return init_state() == fully_initialized; }
 559   bool is_not_initialized() const          { return init_state() <  being_initialized; }
 560   bool is_being_initialized() const        { return init_state() == being_initialized; }
 561   bool is_in_error_state() const           { return init_state() == initialization_error; }
 562   bool is_init_thread(JavaThread *thread)  { return thread == Atomic::load(&_init_thread); }
 563   ClassState  init_state() const           { return Atomic::load(&_init_state); }
 564   const char* init_state_name() const;
 565   bool is_rewritten() const                { return _misc_flags.rewritten(); }
 566 
 567   class LockLinkState : public StackObj {
 568     InstanceKlass* _ik;
 569     JavaThread*    _current;
 570    public:
 571     LockLinkState(InstanceKlass* ik, JavaThread* current) : _ik(ik), _current(current) {
 572       ik->check_link_state_and_wait(current);
 573     }
 574     ~LockLinkState() {
 575       if (!_ik->is_linked()) {
 576         // Reset to loaded if linking failed.
 577         _ik->set_initialization_state_and_notify(loaded, _current);
 578       }
 579     }
 580   };
 581 
 582   // is this a sealed class
 583   bool is_sealed() const;
 584 
 585   // defineClass specified verification
 586   bool should_verify_class() const         { return _misc_flags.should_verify_class(); }
 587   void set_should_verify_class(bool value) { _misc_flags.set_should_verify_class(value); }
 588 
 589   // marking
 590   bool is_marked_dependent() const         { return _misc_flags.is_marked_dependent(); }
 591   void set_is_marked_dependent(bool value) { _misc_flags.set_is_marked_dependent(value); }
 592 
 593   static ByteSize kind_offset() { return in_ByteSize(offset_of(InstanceKlass, _kind)); }
 594   static ByteSize misc_flags_offset() { return in_ByteSize(offset_of(InstanceKlass, _misc_flags)); }
 595 
 596   // initialization (virtuals from Klass)
 597   bool should_be_initialized() const;  // means that initialize should be called
 598   void initialize(TRAPS);
 599   void link_class(TRAPS);
 600   bool link_class_or_fail(TRAPS); // returns false on failure
 601   void rewrite_class(TRAPS);
 602   void link_methods(TRAPS);
 603   Method* class_initializer() const;
 604 
 605   // reference type
 606   ReferenceType reference_type() const     { return (ReferenceType)_reference_type; }
 607 
 608   // this class cp index
 609   u2 this_class_index() const             { return _this_class_index; }
 610   void set_this_class_index(u2 index)     { _this_class_index = index; }
 611 
 612   static ByteSize reference_type_offset() { return byte_offset_of(InstanceKlass, _reference_type); }
 613 
 614   // find local field, returns true if found
 615   bool find_local_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const;
 616   // find field in direct superinterfaces, returns the interface in which the field is defined
 617   Klass* find_interface_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const;
 618   // find field according to JVM spec 5.4.3.2, returns the klass in which the field is defined
 619   Klass* find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const;
 620   // find instance or static fields according to JVM spec 5.4.3.2, returns the klass in which the field is defined
 621   Klass* find_field(Symbol* name, Symbol* sig, bool is_static, fieldDescriptor* fd) const;
 622 
 623   // find a non-static or static field given its offset within the class.
 624   bool contains_field_offset(int offset);
 625 
 626   bool find_local_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const;
 627   bool find_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const;
 628 
 629  private:
 630   inline static int quick_search(const Array<Method*>* methods, const Symbol* name);
 631 
 632  public:
 633   static void disable_method_binary_search() {
 634     _disable_method_binary_search = true;
 635   }
 636 
 637   // find a local method (returns null if not found)
 638   Method* find_method(const Symbol* name, const Symbol* signature) const;
 639   static Method* find_method(const Array<Method*>* methods,
 640                              const Symbol* name,
 641                              const Symbol* signature);
 642 
 643   // find a local method, but skip static methods
 644   Method* find_instance_method(const Symbol* name, const Symbol* signature,
 645                                PrivateLookupMode private_mode) const;
 646   static Method* find_instance_method(const Array<Method*>* methods,
 647                                       const Symbol* name,
 648                                       const Symbol* signature,
 649                                       PrivateLookupMode private_mode);
 650 
 651   // find a local method (returns null if not found)
 652   Method* find_local_method(const Symbol* name,
 653                             const Symbol* signature,
 654                             OverpassLookupMode overpass_mode,
 655                             StaticLookupMode static_mode,
 656                             PrivateLookupMode private_mode) const;
 657 
 658   // find a local method from given methods array (returns null if not found)
 659   static Method* find_local_method(const Array<Method*>* methods,
 660                                    const Symbol* name,
 661                                    const Symbol* signature,
 662                                    OverpassLookupMode overpass_mode,
 663                                    StaticLookupMode static_mode,
 664                                    PrivateLookupMode private_mode);
 665 
 666   // find a local method index in methods or default_methods (returns -1 if not found)
 667   static int find_method_index(const Array<Method*>* methods,
 668                                const Symbol* name,
 669                                const Symbol* signature,
 670                                OverpassLookupMode overpass_mode,
 671                                StaticLookupMode static_mode,
 672                                PrivateLookupMode private_mode);
 673 
 674   // lookup operation (returns null if not found)
 675   Method* uncached_lookup_method(const Symbol* name,
 676                                  const Symbol* signature,
 677                                  OverpassLookupMode overpass_mode,
 678                                  PrivateLookupMode private_mode = PrivateLookupMode::find) const;
 679 
 680   // lookup a method in all the interfaces that this class implements
 681   // (returns null if not found)
 682   Method* lookup_method_in_all_interfaces(Symbol* name, Symbol* signature, DefaultsLookupMode defaults_mode) const;
 683 
 684   // lookup a method in local defaults then in all interfaces
 685   // (returns null if not found)
 686   Method* lookup_method_in_ordered_interfaces(Symbol* name, Symbol* signature) const;
 687 
 688   // Find method indices by name.  If a method with the specified name is
 689   // found the index to the first method is returned, and 'end' is filled in
 690   // with the index of first non-name-matching method.  If no method is found
 691   // -1 is returned.
 692   int find_method_by_name(const Symbol* name, int* end) const;
 693   static int find_method_by_name(const Array<Method*>* methods,
 694                                  const Symbol* name, int* end);
 695 
 696   // constant pool
 697   ConstantPool* constants() const        { return _constants; }
 698   void set_constants(ConstantPool* c)    { _constants = c; }
 699 
 700   // protection domain
 701   oop protection_domain() const;
 702 
 703   // signers
 704   objArrayOop signers() const;
 705 
 706   bool is_contended() const                { return _misc_flags.is_contended(); }
 707   void set_is_contended(bool value)        { _misc_flags.set_is_contended(value); }
 708 
 709   // source file name
 710   Symbol* source_file_name() const               { return _constants->source_file_name(); }
 711   u2 source_file_name_index() const              { return _constants->source_file_name_index(); }
 712   void set_source_file_name_index(u2 sourcefile_index) { _constants->set_source_file_name_index(sourcefile_index); }
 713 
 714   // minor and major version numbers of class file
 715   u2 minor_version() const                 { return _constants->minor_version(); }
 716   void set_minor_version(u2 minor_version) { _constants->set_minor_version(minor_version); }
 717   u2 major_version() const                 { return _constants->major_version(); }
 718   void set_major_version(u2 major_version) { _constants->set_major_version(major_version); }
 719 
 720   // source debug extension
 721   const char* source_debug_extension() const { return _source_debug_extension; }
 722   void set_source_debug_extension(const char* array, int length);
 723 
 724   // nonstatic oop-map blocks
 725   static int nonstatic_oop_map_size(unsigned int oop_map_count) {
 726     return oop_map_count * OopMapBlock::size_in_words();
 727   }
 728   unsigned int nonstatic_oop_map_count() const {
 729     return _nonstatic_oop_map_size / OopMapBlock::size_in_words();
 730   }
 731   int nonstatic_oop_map_size() const { return _nonstatic_oop_map_size; }
 732   void set_nonstatic_oop_map_size(int words) {
 733     _nonstatic_oop_map_size = words;
 734   }
 735 
 736   bool has_contended_annotations() const { return _misc_flags.has_contended_annotations(); }
 737   void set_has_contended_annotations(bool value)  { _misc_flags.set_has_contended_annotations(value); }
 738 
 739 #if INCLUDE_JVMTI
 740   // Redefinition locking.  Class can only be redefined by one thread at a time.
 741   // The flag is in access_flags so that it can be set and reset using atomic
 742   // operations, and not be reset by other misc_flag settings.
 743   bool is_being_redefined() const          { return _misc_flags.is_being_redefined(); }
 744   void set_is_being_redefined(bool value)  { _misc_flags.set_is_being_redefined(value); }
 745 
 746   // RedefineClasses() support for previous versions:
 747   void add_previous_version(InstanceKlass* ik, int emcp_method_count);
 748   void purge_previous_version_list();
 749 
 750   InstanceKlass* previous_versions() const { return _previous_versions; }
 751 #else
 752   InstanceKlass* previous_versions() const { return nullptr; }
 753 #endif
 754 
 755   InstanceKlass* get_klass_version(int version) {
 756     for (InstanceKlass* ik = this; ik != nullptr; ik = ik->previous_versions()) {
 757       if (ik->constants()->version() == version) {
 758         return ik;
 759       }
 760     }
 761     return nullptr;
 762   }
 763 
 764   bool has_been_redefined() const { return _misc_flags.has_been_redefined(); }
 765   void set_has_been_redefined() { _misc_flags.set_has_been_redefined(true); }
 766 
 767   bool is_scratch_class() const { return _misc_flags.is_scratch_class(); }
 768   void set_is_scratch_class() { _misc_flags.set_is_scratch_class(true); }
 769 
 770   bool has_resolved_methods() const { return _misc_flags.has_resolved_methods(); }
 771   void set_has_resolved_methods()   { _misc_flags.set_has_resolved_methods(true); }
 772   void set_has_resolved_methods(bool value)   { _misc_flags.set_has_resolved_methods(value); }
 773 
 774 public:
 775 #if INCLUDE_JVMTI
 776 
 777   void init_previous_versions() {
 778     _previous_versions = nullptr;
 779   }
 780 
 781  private:
 782   static bool  _should_clean_previous_versions;
 783  public:
 784   static void purge_previous_versions(InstanceKlass* ik) {
 785     if (ik->has_been_redefined()) {
 786       ik->purge_previous_version_list();
 787     }
 788   }
 789 
 790   static bool should_clean_previous_versions_and_reset();
 791   static bool should_clean_previous_versions() { return _should_clean_previous_versions; }
 792 
 793   // JVMTI: Support for caching a class file before it is modified by an agent that can do retransformation
 794   void set_cached_class_file(JvmtiCachedClassFileData *data) {
 795     _cached_class_file = data;
 796   }
 797   JvmtiCachedClassFileData * get_cached_class_file();
 798   jint get_cached_class_file_len();
 799   unsigned char * get_cached_class_file_bytes();
 800 
 801   // JVMTI: Support for caching of field indices, types, and offsets
 802   void set_jvmti_cached_class_field_map(JvmtiCachedClassFieldMap* descriptor) {
 803     _jvmti_cached_class_field_map = descriptor;
 804   }
 805   JvmtiCachedClassFieldMap* jvmti_cached_class_field_map() const {
 806     return _jvmti_cached_class_field_map;
 807   }
 808 #else // INCLUDE_JVMTI
 809 
 810   static void purge_previous_versions(InstanceKlass* ik) { return; };
 811   static bool should_clean_previous_versions_and_reset() { return false; }
 812 
 813   void set_cached_class_file(JvmtiCachedClassFileData *data) {
 814     assert(data == nullptr, "unexpected call with JVMTI disabled");
 815   }
 816   JvmtiCachedClassFileData * get_cached_class_file() { return (JvmtiCachedClassFileData *)nullptr; }
 817 
 818 #endif // INCLUDE_JVMTI
 819 
 820   bool has_nonstatic_concrete_methods() const { return _misc_flags.has_nonstatic_concrete_methods(); }
 821   void set_has_nonstatic_concrete_methods(bool b) { _misc_flags.set_has_nonstatic_concrete_methods(b); }
 822 
 823   bool declares_nonstatic_concrete_methods() const { return _misc_flags.declares_nonstatic_concrete_methods(); }
 824   void set_declares_nonstatic_concrete_methods(bool b) { _misc_flags.set_declares_nonstatic_concrete_methods(b); }
 825 
 826   bool has_vanilla_constructor() const  { return _misc_flags.has_vanilla_constructor(); }
 827   void set_has_vanilla_constructor()    { _misc_flags.set_has_vanilla_constructor(true); }
 828   bool has_miranda_methods () const     { return _misc_flags.has_miranda_methods(); }
 829   void set_has_miranda_methods()        { _misc_flags.set_has_miranda_methods(true); }
 830   bool has_final_method() const         { return _misc_flags.has_final_method(); }
 831   void set_has_final_method()           { _misc_flags.set_has_final_method(true); }
 832 
 833   // for adding methods, ConstMethod::UNSET_IDNUM means no more ids available
 834   inline u2 next_method_idnum();
 835   void set_initial_method_idnum(u2 value)             { _idnum_allocated_count = value; }
 836 
 837   // generics support
 838   Symbol* generic_signature() const                   { return _constants->generic_signature(); }
 839   u2 generic_signature_index() const                  { return _constants->generic_signature_index(); }
 840   void set_generic_signature_index(u2 sig_index)      { _constants->set_generic_signature_index(sig_index); }
 841 
 842   u2 enclosing_method_data(int offset) const;
 843   u2 enclosing_method_class_index() const {
 844     return enclosing_method_data(enclosing_method_class_index_offset);
 845   }
 846   u2 enclosing_method_method_index() {
 847     return enclosing_method_data(enclosing_method_method_index_offset);
 848   }
 849   void set_enclosing_method_indices(u2 class_index,
 850                                     u2 method_index);
 851 
 852   // jmethodID support
 853   jmethodID get_jmethod_id(const methodHandle& method_h);
 854   jmethodID get_jmethod_id_fetch_or_update(size_t idnum,
 855                      jmethodID new_id, jmethodID* new_jmeths,
 856                      jmethodID* to_dealloc_id_p,
 857                      jmethodID** to_dealloc_jmeths_p);
 858   static void get_jmethod_id_length_value(jmethodID* cache, size_t idnum,
 859                 size_t *length_p, jmethodID* id_p);
 860   void ensure_space_for_methodids(int start_offset = 0);
 861   jmethodID jmethod_id_or_null(Method* method);
 862 
 863   // annotations support
 864   Annotations* annotations() const          { return _annotations; }
 865   void set_annotations(Annotations* anno)   { _annotations = anno; }
 866 
 867   AnnotationArray* class_annotations() const {
 868     return (_annotations != nullptr) ? _annotations->class_annotations() : nullptr;
 869   }
 870   Array<AnnotationArray*>* fields_annotations() const {
 871     return (_annotations != nullptr) ? _annotations->fields_annotations() : nullptr;
 872   }
 873   AnnotationArray* class_type_annotations() const {
 874     return (_annotations != nullptr) ? _annotations->class_type_annotations() : nullptr;
 875   }
 876   Array<AnnotationArray*>* fields_type_annotations() const {
 877     return (_annotations != nullptr) ? _annotations->fields_type_annotations() : nullptr;
 878   }
 879   // allocation
 880   instanceOop allocate_instance(TRAPS);
 881   static instanceOop allocate_instance(oop cls, TRAPS);
 882 
 883   // additional member function to return a handle
 884   instanceHandle allocate_instance_handle(TRAPS);
 885 
 886   objArrayOop allocate_objArray(int n, int length, TRAPS);
 887   // Helper function
 888   static instanceOop register_finalizer(instanceOop i, TRAPS);
 889 
 890   // Check whether reflection/jni/jvm code is allowed to instantiate this class;
 891   // if not, throw either an Error or an Exception.
 892   virtual void check_valid_for_instantiation(bool throwError, TRAPS);
 893 
 894   // initialization
 895   void call_class_initializer(TRAPS);
 896   void set_initialization_state_and_notify(ClassState state, JavaThread* current);
 897 
 898   // OopMapCache support
 899   OopMapCache* oop_map_cache()               { return _oop_map_cache; }
 900   void set_oop_map_cache(OopMapCache *cache) { _oop_map_cache = cache; }
 901   void mask_for(const methodHandle& method, int bci, InterpreterOopMap* entry);
 902 
 903   // JNI identifier support (for static fields - for jni performance)
 904   JNIid* jni_ids()                               { return _jni_ids; }
 905   void set_jni_ids(JNIid* ids)                   { _jni_ids = ids; }
 906   JNIid* jni_id_for(int offset);
 907 
 908   // maintenance of deoptimization dependencies
 909   inline DependencyContext dependencies();
 910   void mark_dependent_nmethods(DeoptimizationScope* deopt_scope, KlassDepChange& changes);
 911   void add_dependent_nmethod(nmethod* nm);
 912   void clean_dependency_context();
 913   // Setup link to hierarchy and deoptimize
 914   void add_to_hierarchy(JavaThread* current);
 915 
 916   // On-stack replacement support
 917   nmethod* osr_nmethods_head() const         { return _osr_nmethods_head; };
 918   void set_osr_nmethods_head(nmethod* h)     { _osr_nmethods_head = h; };
 919   void add_osr_nmethod(nmethod* n);
 920   bool remove_osr_nmethod(nmethod* n);
 921   int mark_osr_nmethods(DeoptimizationScope* deopt_scope, const Method* m);
 922   nmethod* lookup_osr_nmethod(const Method* m, int bci, int level, bool match_level) const;
 923 
 924 #if INCLUDE_JVMTI
 925   // Breakpoint support (see methods on Method* for details)
 926   BreakpointInfo* breakpoints() const       { return _breakpoints; };
 927   void set_breakpoints(BreakpointInfo* bps) { _breakpoints = bps; };
 928 #endif
 929 
 930   // support for stub routines
 931   static ByteSize init_state_offset()  { return byte_offset_of(InstanceKlass, _init_state); }
 932   JFR_ONLY(DEFINE_KLASS_TRACE_ID_OFFSET;)
 933   static ByteSize init_thread_offset() { return byte_offset_of(InstanceKlass, _init_thread); }
 934 
 935   static ByteSize inline_type_field_klasses_offset() { return in_ByteSize(offset_of(InstanceKlass, _inline_type_field_klasses)); }
 936   static ByteSize adr_inlineklass_fixed_block_offset() { return in_ByteSize(offset_of(InstanceKlass, _adr_inlineklass_fixed_block)); }
 937 
 938   // subclass/subinterface checks
 939   bool implements_interface(Klass* k) const;
 940   bool is_same_or_direct_interface(Klass* k) const;
 941 
 942 #ifdef ASSERT
 943   // check whether this class or one of its superclasses was redefined
 944   bool has_redefined_this_or_super() const;
 945 #endif
 946 
 947   // Access to the implementor of an interface.
 948   InstanceKlass* implementor() const;
 949   void set_implementor(InstanceKlass* ik);
 950   int  nof_implementors() const;
 951   void add_implementor(InstanceKlass* ik);  // ik is a new class that implements this interface
 952   void init_implementor();           // initialize
 953 
 954  private:
 955   // link this class into the implementors list of every interface it implements
 956   void process_interfaces();
 957 
 958  public:
 959   // virtual operations from Klass
 960   GrowableArray<Klass*>* compute_secondary_supers(int num_extra_slots,
 961                                                   Array<InstanceKlass*>* transitive_interfaces);
 962   bool can_be_primary_super_slow() const;
 963   size_t oop_size(oop obj)  const             { return size_helper(); }
 964   // slow because it's a virtual call and used for verifying the layout_helper.
 965   // Using the layout_helper bits, we can call is_instance_klass without a virtual call.
 966   DEBUG_ONLY(bool is_instance_klass_slow() const      { return true; })
 967 
 968   // Iterators
 969   void do_local_static_fields(FieldClosure* cl);
 970   void do_nonstatic_fields(FieldClosure* cl); // including inherited fields
 971   void do_local_static_fields(void f(fieldDescriptor*, Handle, TRAPS), Handle, TRAPS);
 972   void print_nonstatic_fields(FieldClosure* cl); // including inherited and injected fields
 973 
 974   void methods_do(void f(Method* method));
 975 
 976   static InstanceKlass* cast(Klass* k) {
 977     return const_cast<InstanceKlass*>(cast(const_cast<const Klass*>(k)));
 978   }
 979 
 980   static const InstanceKlass* cast(const Klass* k) {
 981     assert(k != nullptr, "k should not be null");
 982     assert(k->is_instance_klass(), "cast to InstanceKlass");
 983     return static_cast<const InstanceKlass*>(k);
 984   }
 985 
 986   virtual InstanceKlass* java_super() const {
 987     return (super() == nullptr) ? nullptr : cast(super());
 988   }
 989 
 990   // Sizing (in words)
 991   static int header_size()            { return sizeof(InstanceKlass)/wordSize; }
 992 
 993   static int size(int vtable_length, int itable_length,
 994                   int nonstatic_oop_map_size,
 995                   bool is_interface,
 996                   int java_fields, bool is_inline_type) {
 997     return align_metadata_size(header_size() +
 998            vtable_length +
 999            itable_length +
1000            nonstatic_oop_map_size +
1001            (is_interface ? (int)sizeof(Klass*)/wordSize : 0) +
1002            (java_fields * (int)sizeof(Klass*)/wordSize) +
1003            (is_inline_type ? (int)sizeof(InlineKlassFixedBlock) : 0));
1004   }
1005 
1006   int size() const                    { return size(vtable_length(),
1007                                                itable_length(),
1008                                                nonstatic_oop_map_size(),
1009                                                is_interface(),
1010                                                has_inline_type_fields() ? java_fields_count() : 0,
1011                                                is_inline_klass());
1012   }
1013 
1014 
1015   inline intptr_t* start_of_itable() const;
1016   inline intptr_t* end_of_itable() const;
1017   inline int itable_offset_in_words() const;
1018   inline oop static_field_base_raw();
1019   bool bounds_check(address addr, bool edge_ok = false, intptr_t size_in_bytes = -1) const PRODUCT_RETURN0;
1020 
1021   inline OopMapBlock* start_of_nonstatic_oop_maps() const;
1022   inline Klass** end_of_nonstatic_oop_maps() const;
1023 
1024   inline InstanceKlass* volatile* adr_implementor() const;
1025 
1026   inline address adr_inline_type_field_klasses() const;
1027   inline Klass* get_inline_type_field_klass(int idx) const;
1028   inline Klass* get_inline_type_field_klass_or_null(int idx) const;
1029   inline void set_inline_type_field_klass(int idx, Klass* k);
1030   inline void reset_inline_type_field_klass(int idx);
1031 
1032   // Use this to return the size of an instance in heap words:
1033   virtual int size_helper() const {
1034     return layout_helper_to_size_helper(layout_helper());
1035   }
1036 
1037   // This bit is initialized in classFileParser.cpp.
1038   // It is false under any of the following conditions:
1039   //  - the class is abstract (including any interface)
1040   //  - the class has a finalizer (if !RegisterFinalizersAtInit)
1041   //  - the class size is larger than FastAllocateSizeLimit
1042   //  - the class is java/lang/Class, which cannot be allocated directly
1043   bool can_be_fastpath_allocated() const {
1044     return !layout_helper_needs_slow_path(layout_helper());
1045   }
1046 
1047   // Java itable
1048   klassItable itable() const;        // return klassItable wrapper
1049   Method* method_at_itable(InstanceKlass* holder, int index, TRAPS);
1050   Method* method_at_itable_or_null(InstanceKlass* holder, int index, bool& itable_entry_found);
1051   int vtable_index_of_interface_method(Method* method);
1052 
1053 #if INCLUDE_JVMTI
1054   void adjust_default_methods(bool* trace_name_printed);
1055 #endif // INCLUDE_JVMTI
1056 
1057   void clean_weak_instanceklass_links();
1058  private:
1059   void clean_implementors_list();
1060   void clean_method_data();
1061 
1062  public:
1063   // Explicit metaspace deallocation of fields
1064   // For RedefineClasses and class file parsing errors, we need to deallocate
1065   // instanceKlasses and the metadata they point to.
1066   void deallocate_contents(ClassLoaderData* loader_data);
1067   static void deallocate_methods(ClassLoaderData* loader_data,
1068                                  Array<Method*>* methods);
1069   void static deallocate_interfaces(ClassLoaderData* loader_data,
1070                                     const Klass* super_klass,
1071                                     Array<InstanceKlass*>* local_interfaces,
1072                                     Array<InstanceKlass*>* transitive_interfaces);
1073   void static deallocate_record_components(ClassLoaderData* loader_data,
1074                                            Array<RecordComponent*>* record_component);
1075 
1076   // The constant pool is on stack if any of the methods are executing or
1077   // referenced by handles.
1078   bool on_stack() const { return _constants->on_stack(); }
1079 
1080   // callbacks for actions during class unloading
1081   static void unload_class(InstanceKlass* ik);
1082 
1083   virtual void release_C_heap_structures(bool release_sub_metadata = true);
1084 
1085   // Naming
1086   const char* signature_name() const;
1087   const char* signature_name_of_carrier(char c) const;
1088 
1089   // Oop fields (and metadata) iterators
1090   //
1091   // The InstanceKlass iterators also visits the Object's klass.
1092 
1093   // Forward iteration
1094  public:
1095   // Iterate over all oop fields in the oop maps.
1096   template <typename T, class OopClosureType>
1097   inline void oop_oop_iterate_oop_maps(oop obj, OopClosureType* closure);
1098 
1099   // Iterate over all oop fields and metadata.
1100   template <typename T, class OopClosureType>
1101   inline void oop_oop_iterate(oop obj, OopClosureType* closure);
1102 
1103   // Iterate over all oop fields in one oop map.
1104   template <typename T, class OopClosureType>
1105   inline void oop_oop_iterate_oop_map(OopMapBlock* map, oop obj, OopClosureType* closure);
1106 
1107 
1108   // Reverse iteration
1109   // Iterate over all oop fields and metadata.
1110   template <typename T, class OopClosureType>
1111   inline void oop_oop_iterate_reverse(oop obj, OopClosureType* closure);
1112 
1113  private:
1114   // Iterate over all oop fields in the oop maps.
1115   template <typename T, class OopClosureType>
1116   inline void oop_oop_iterate_oop_maps_reverse(oop obj, OopClosureType* closure);
1117 
1118   // Iterate over all oop fields in one oop map.
1119   template <typename T, class OopClosureType>
1120   inline void oop_oop_iterate_oop_map_reverse(OopMapBlock* map, oop obj, OopClosureType* closure);
1121 
1122 
1123   // Bounded range iteration
1124  public:
1125   // Iterate over all oop fields in the oop maps.
1126   template <typename T, class OopClosureType>
1127   inline void oop_oop_iterate_oop_maps_bounded(oop obj, OopClosureType* closure, MemRegion mr);
1128 
1129   // Iterate over all oop fields and metadata.
1130   template <typename T, class OopClosureType>
1131   inline void oop_oop_iterate_bounded(oop obj, OopClosureType* closure, MemRegion mr);
1132 
1133  private:
1134   // Iterate over all oop fields in one oop map.
1135   template <typename T, class OopClosureType>
1136   inline void oop_oop_iterate_oop_map_bounded(OopMapBlock* map, oop obj, OopClosureType* closure, MemRegion mr);
1137 
1138 
1139  public:
1140   u2 idnum_allocated_count() const      { return _idnum_allocated_count; }
1141 
1142  private:
1143   // initialization state
1144   void set_init_state(ClassState state);
1145   void set_rewritten()                  { _misc_flags.set_rewritten(true); }
1146   void set_init_thread(JavaThread *thread)  {
1147     assert((thread == JavaThread::current() && _init_thread == nullptr) ||
1148            (thread == nullptr && _init_thread == JavaThread::current()), "Only one thread is allowed to own initialization");
1149     Atomic::store(&_init_thread, thread);
1150   }
1151 
1152   // The RedefineClasses() API can cause new method idnums to be needed
1153   // which will cause the caches to grow. Safety requires different
1154   // cache management logic if the caches can grow instead of just
1155   // going from null to non-null.
1156   bool idnum_can_increment() const      { return has_been_redefined(); }
1157   inline jmethodID* methods_jmethod_ids_acquire() const;
1158   inline void release_set_methods_jmethod_ids(jmethodID* jmeths);
1159 
1160   // Lock during initialization
1161 public:
1162   // Returns the array class for the n'th dimension
1163   virtual Klass* array_klass(int n, TRAPS);
1164   virtual Klass* array_klass_or_null(int n);
1165 
1166   // Returns the array class with this class as element type
1167   virtual Klass* array_klass(TRAPS);
1168   virtual Klass* array_klass_or_null();
1169 
1170   static void clean_initialization_error_table();
1171 
1172   Monitor* init_monitor() const { return _init_monitor; }
1173 private:
1174   void check_link_state_and_wait(JavaThread* current);
1175   bool link_class_impl                           (TRAPS);
1176   bool verify_code                               (TRAPS);
1177   void initialize_impl                           (TRAPS);
1178   void initialize_super_interfaces               (TRAPS);
1179 
1180   void add_initialization_error(JavaThread* current, Handle exception);
1181   oop get_initialization_error(JavaThread* current);
1182 
1183   // find a local method (returns null if not found)
1184   Method* find_method_impl(const Symbol* name,
1185                            const Symbol* signature,
1186                            OverpassLookupMode overpass_mode,
1187                            StaticLookupMode static_mode,
1188                            PrivateLookupMode private_mode) const;
1189 
1190   static Method* find_method_impl(const Array<Method*>* methods,
1191                                   const Symbol* name,
1192                                   const Symbol* signature,
1193                                   OverpassLookupMode overpass_mode,
1194                                   StaticLookupMode static_mode,
1195                                   PrivateLookupMode private_mode);
1196 
1197 #if INCLUDE_JVMTI
1198   // RedefineClasses support
1199   void link_previous_versions(InstanceKlass* pv) { _previous_versions = pv; }
1200   void mark_newly_obsolete_methods(Array<Method*>* old_methods, int emcp_method_count);
1201 #endif
1202   // log class name to classlist
1203   void log_to_classlist() const;
1204 public:
1205 
1206 #if INCLUDE_CDS
1207   // CDS support - remove and restore oops from metadata. Oops are not shared.
1208   virtual void remove_unshareable_info();
1209   void remove_unshareable_flags();
1210   virtual void remove_java_mirror();
1211   virtual void restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, PackageEntry* pkg_entry, TRAPS);
1212   void init_shared_package_entry();
1213   bool can_be_verified_at_dumptime() const;
1214   bool methods_contain_jsr_bytecode() const;
1215   void compute_has_loops_flag_for_methods();
1216 #endif
1217 
1218   jint compute_modifier_flags() const;
1219 
1220 public:
1221   // JVMTI support
1222   jint jvmti_class_status() const;
1223 
1224   virtual void metaspace_pointers_do(MetaspaceClosure* iter);
1225 
1226  public:
1227   // Printing
1228   void print_on(outputStream* st) const;
1229   void print_value_on(outputStream* st) const;
1230 
1231   void oop_print_value_on(oop obj, outputStream* st);
1232 
1233   void oop_print_on      (oop obj, outputStream* st);
1234 
1235 #ifndef PRODUCT
1236   void print_dependent_nmethods(bool verbose = false);
1237   bool is_dependent_nmethod(nmethod* nm);
1238   bool verify_itable_index(int index);
1239 #endif
1240 
1241   const char* internal_name() const;
1242 
1243   // Verification
1244   void verify_on(outputStream* st);
1245 
1246   void oop_verify_on(oop obj, outputStream* st);
1247 
1248   // Logging
1249   void print_class_load_logging(ClassLoaderData* loader_data,
1250                                 const ModuleEntry* module_entry,
1251                                 const ClassFileStream* cfs) const;
1252 };
1253 
1254 // for adding methods
1255 // UNSET_IDNUM return means no more ids available
1256 inline u2 InstanceKlass::next_method_idnum() {
1257   if (_idnum_allocated_count == ConstMethod::MAX_IDNUM) {
1258     return ConstMethod::UNSET_IDNUM; // no more ids available
1259   } else {
1260     return _idnum_allocated_count++;
1261   }
1262 }
1263 
1264 class PrintClassClosure : public KlassClosure {
1265 private:
1266   outputStream* _st;
1267   bool _verbose;
1268 public:
1269   PrintClassClosure(outputStream* st, bool verbose);
1270 
1271   void do_klass(Klass* k);
1272 };
1273 
1274 /* JNIid class for jfieldIDs only */
1275 class JNIid: public CHeapObj<mtClass> {
1276   friend class VMStructs;
1277  private:
1278   Klass*             _holder;
1279   JNIid*             _next;
1280   int                _offset;
1281 #ifdef ASSERT
1282   bool               _is_static_field_id;
1283 #endif
1284 
1285  public:
1286   // Accessors
1287   Klass* holder() const           { return _holder; }
1288   int offset() const              { return _offset; }
1289   JNIid* next()                   { return _next; }
1290   // Constructor
1291   JNIid(Klass* holder, int offset, JNIid* next);
1292   // Identifier lookup
1293   JNIid* find(int offset);
1294 
1295   bool find_local_field(fieldDescriptor* fd) {
1296     return InstanceKlass::cast(holder())->find_local_field_from_offset(offset(), true, fd);
1297   }
1298 
1299   static void deallocate(JNIid* id);
1300   // Debugging
1301 #ifdef ASSERT
1302   bool is_static_field_id() const { return _is_static_field_id; }
1303   void set_is_static_field_id()   { _is_static_field_id = true; }
1304 #endif
1305   void verify(Klass* holder);
1306 };
1307 
1308 // An iterator that's used to access the inner classes indices in the
1309 // InstanceKlass::_inner_classes array.
1310 class InnerClassesIterator : public StackObj {
1311  private:
1312   Array<jushort>* _inner_classes;
1313   int _length;
1314   int _idx;
1315  public:
1316 
1317   InnerClassesIterator(const InstanceKlass* k) {
1318     _inner_classes = k->inner_classes();
1319     if (k->inner_classes() != nullptr) {
1320       _length = _inner_classes->length();
1321       // The inner class array's length should be the multiple of
1322       // inner_class_next_offset if it only contains the InnerClasses
1323       // attribute data, or it should be
1324       // n*inner_class_next_offset+enclosing_method_attribute_size
1325       // if it also contains the EnclosingMethod data.
1326       assert((_length % InstanceKlass::inner_class_next_offset == 0 ||
1327               _length % InstanceKlass::inner_class_next_offset == InstanceKlass::enclosing_method_attribute_size),
1328              "just checking");
1329       // Remove the enclosing_method portion if exists.
1330       if (_length % InstanceKlass::inner_class_next_offset == InstanceKlass::enclosing_method_attribute_size) {
1331         _length -= InstanceKlass::enclosing_method_attribute_size;
1332       }
1333     } else {
1334       _length = 0;
1335     }
1336     _idx = 0;
1337   }
1338 
1339   int length() const {
1340     return _length;
1341   }
1342 
1343   void next() {
1344     _idx += InstanceKlass::inner_class_next_offset;
1345   }
1346 
1347   bool done() const {
1348     return (_idx >= _length);
1349   }
1350 
1351   u2 inner_class_info_index() const {
1352     return _inner_classes->at(
1353                _idx + InstanceKlass::inner_class_inner_class_info_offset);
1354   }
1355 
1356   void set_inner_class_info_index(u2 index) {
1357     _inner_classes->at_put(
1358                _idx + InstanceKlass::inner_class_inner_class_info_offset, index);
1359   }
1360 
1361   u2 outer_class_info_index() const {
1362     return _inner_classes->at(
1363                _idx + InstanceKlass::inner_class_outer_class_info_offset);
1364   }
1365 
1366   void set_outer_class_info_index(u2 index) {
1367     _inner_classes->at_put(
1368                _idx + InstanceKlass::inner_class_outer_class_info_offset, index);
1369   }
1370 
1371   u2 inner_name_index() const {
1372     return _inner_classes->at(
1373                _idx + InstanceKlass::inner_class_inner_name_offset);
1374   }
1375 
1376   void set_inner_name_index(u2 index) {
1377     _inner_classes->at_put(
1378                _idx + InstanceKlass::inner_class_inner_name_offset, index);
1379   }
1380 
1381   u2 inner_access_flags() const {
1382     return _inner_classes->at(
1383                _idx + InstanceKlass::inner_class_access_flags_offset);
1384   }
1385 };
1386 
1387 // Iterator over class hierarchy under a particular class. Implements depth-first pre-order traversal.
1388 // Usage:
1389 //  for (ClassHierarchyIterator iter(root_klass); !iter.done(); iter.next()) {
1390 //    Klass* k = iter.klass();
1391 //    ...
1392 //  }
1393 class ClassHierarchyIterator : public StackObj {
1394  private:
1395   InstanceKlass* _root;
1396   Klass*         _current;
1397   bool           _visit_subclasses;
1398 
1399  public:
1400   ClassHierarchyIterator(InstanceKlass* root) : _root(root), _current(root), _visit_subclasses(true) {
1401     assert(_root == _current, "required"); // initial state
1402   }
1403 
1404   bool done() {
1405     return (_current == nullptr);
1406   }
1407 
1408   // Make a step iterating over the class hierarchy under the root class.
1409   // Skips subclasses if requested.
1410   void next();
1411 
1412   Klass* klass() {
1413     assert(!done(), "sanity");
1414     return _current;
1415   }
1416 
1417   // Skip subclasses of the current class.
1418   void skip_subclasses() {
1419     _visit_subclasses = false;
1420   }
1421 };
1422 
1423 #endif // SHARE_OOPS_INSTANCEKLASS_HPP