1 /*
   2  * Copyright (c) 1997, 2024, 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 #include "precompiled.hpp"
  26 #include "cds/archiveUtils.hpp"
  27 #include "cds/cdsConfig.hpp"
  28 #include "cds/classListWriter.hpp"
  29 #include "cds/heapShared.hpp"
  30 #include "cds/metaspaceShared.hpp"
  31 #include "classfile/classFileParser.hpp"
  32 #include "classfile/classFileStream.hpp"
  33 #include "classfile/classLoader.hpp"
  34 #include "classfile/classLoaderData.inline.hpp"
  35 #include "classfile/javaClasses.hpp"
  36 #include "classfile/moduleEntry.hpp"
  37 #include "classfile/systemDictionary.hpp"
  38 #include "classfile/systemDictionaryShared.hpp"
  39 #include "classfile/verifier.hpp"
  40 #include "classfile/vmClasses.hpp"
  41 #include "classfile/vmSymbols.hpp"
  42 #include "code/codeCache.hpp"
  43 #include "code/dependencyContext.hpp"
  44 #include "compiler/compilationPolicy.hpp"
  45 #include "compiler/compileBroker.hpp"
  46 #include "gc/shared/collectedHeap.inline.hpp"
  47 #include "interpreter/bytecodeStream.hpp"
  48 #include "interpreter/oopMapCache.hpp"
  49 #include "interpreter/rewriter.hpp"
  50 #include "jvm.h"
  51 #include "jvmtifiles/jvmti.h"
  52 #include "logging/log.hpp"
  53 #include "logging/logMessage.hpp"
  54 #include "logging/logStream.hpp"
  55 #include "memory/allocation.inline.hpp"
  56 #include "memory/iterator.inline.hpp"
  57 #include "memory/metadataFactory.hpp"
  58 #include "memory/metaspaceClosure.hpp"
  59 #include "memory/oopFactory.hpp"
  60 #include "memory/resourceArea.hpp"
  61 #include "memory/universe.hpp"
  62 #include "oops/fieldStreams.inline.hpp"
  63 #include "oops/constantPool.hpp"
  64 #include "oops/instanceClassLoaderKlass.hpp"
  65 #include "oops/instanceKlass.inline.hpp"
  66 #include "oops/instanceMirrorKlass.hpp"
  67 #include "oops/instanceOop.hpp"
  68 #include "oops/instanceStackChunkKlass.hpp"
  69 #include "oops/klass.inline.hpp"
  70 #include "oops/method.hpp"
  71 #include "oops/oop.inline.hpp"
  72 #include "oops/recordComponent.hpp"
  73 #include "oops/symbol.hpp"
  74 #include "prims/jvmtiExport.hpp"
  75 #include "prims/jvmtiRedefineClasses.hpp"
  76 #include "prims/jvmtiThreadState.hpp"
  77 #include "prims/methodComparator.hpp"
  78 #include "runtime/arguments.hpp"
  79 #include "runtime/deoptimization.hpp"
  80 #include "runtime/atomic.hpp"
  81 #include "runtime/fieldDescriptor.inline.hpp"
  82 #include "runtime/handles.inline.hpp"
  83 #include "runtime/javaCalls.hpp"
  84 #include "runtime/javaThread.inline.hpp"
  85 #include "runtime/mutexLocker.hpp"
  86 #include "runtime/orderAccess.hpp"
  87 #include "runtime/os.inline.hpp"
  88 #include "runtime/reflection.hpp"
  89 #include "runtime/threads.hpp"
  90 #include "services/classLoadingService.hpp"
  91 #include "services/finalizerService.hpp"
  92 #include "services/threadService.hpp"
  93 #include "utilities/dtrace.hpp"
  94 #include "utilities/events.hpp"
  95 #include "utilities/macros.hpp"
  96 #include "utilities/stringUtils.hpp"
  97 #include "utilities/pair.hpp"
  98 #ifdef COMPILER1
  99 #include "c1/c1_Compiler.hpp"
 100 #endif
 101 #if INCLUDE_JFR
 102 #include "jfr/jfrEvents.hpp"
 103 #endif
 104 
 105 #ifdef DTRACE_ENABLED
 106 
 107 
 108 #define HOTSPOT_CLASS_INITIALIZATION_required HOTSPOT_CLASS_INITIALIZATION_REQUIRED
 109 #define HOTSPOT_CLASS_INITIALIZATION_recursive HOTSPOT_CLASS_INITIALIZATION_RECURSIVE
 110 #define HOTSPOT_CLASS_INITIALIZATION_concurrent HOTSPOT_CLASS_INITIALIZATION_CONCURRENT
 111 #define HOTSPOT_CLASS_INITIALIZATION_erroneous HOTSPOT_CLASS_INITIALIZATION_ERRONEOUS
 112 #define HOTSPOT_CLASS_INITIALIZATION_super__failed HOTSPOT_CLASS_INITIALIZATION_SUPER_FAILED
 113 #define HOTSPOT_CLASS_INITIALIZATION_clinit HOTSPOT_CLASS_INITIALIZATION_CLINIT
 114 #define HOTSPOT_CLASS_INITIALIZATION_error HOTSPOT_CLASS_INITIALIZATION_ERROR
 115 #define HOTSPOT_CLASS_INITIALIZATION_end HOTSPOT_CLASS_INITIALIZATION_END
 116 #define DTRACE_CLASSINIT_PROBE(type, thread_type)                \
 117   {                                                              \
 118     char* data = nullptr;                                        \
 119     int len = 0;                                                 \
 120     Symbol* clss_name = name();                                  \
 121     if (clss_name != nullptr) {                                  \
 122       data = (char*)clss_name->bytes();                          \
 123       len = clss_name->utf8_length();                            \
 124     }                                                            \
 125     HOTSPOT_CLASS_INITIALIZATION_##type(                         \
 126       data, len, (void*)class_loader(), thread_type);            \
 127   }
 128 
 129 #define DTRACE_CLASSINIT_PROBE_WAIT(type, thread_type, wait)     \
 130   {                                                              \
 131     char* data = nullptr;                                        \
 132     int len = 0;                                                 \
 133     Symbol* clss_name = name();                                  \
 134     if (clss_name != nullptr) {                                  \
 135       data = (char*)clss_name->bytes();                          \
 136       len = clss_name->utf8_length();                            \
 137     }                                                            \
 138     HOTSPOT_CLASS_INITIALIZATION_##type(                         \
 139       data, len, (void*)class_loader(), thread_type, wait);      \
 140   }
 141 
 142 #else //  ndef DTRACE_ENABLED
 143 
 144 #define DTRACE_CLASSINIT_PROBE(type, thread_type)
 145 #define DTRACE_CLASSINIT_PROBE_WAIT(type, thread_type, wait)
 146 
 147 #endif //  ndef DTRACE_ENABLED
 148 
 149 bool InstanceKlass::_finalization_enabled = true;
 150 
 151 static inline bool is_class_loader(const Symbol* class_name,
 152                                    const ClassFileParser& parser) {
 153   assert(class_name != nullptr, "invariant");
 154 
 155   if (class_name == vmSymbols::java_lang_ClassLoader()) {
 156     return true;
 157   }
 158 
 159   if (vmClasses::ClassLoader_klass_loaded()) {
 160     const Klass* const super_klass = parser.super_klass();
 161     if (super_klass != nullptr) {
 162       if (super_klass->is_subtype_of(vmClasses::ClassLoader_klass())) {
 163         return true;
 164       }
 165     }
 166   }
 167   return false;
 168 }
 169 
 170 static inline bool is_stack_chunk_class(const Symbol* class_name,
 171                                         const ClassLoaderData* loader_data) {
 172   return (class_name == vmSymbols::jdk_internal_vm_StackChunk() &&
 173           loader_data->is_the_null_class_loader_data());
 174 }
 175 
 176 // private: called to verify that k is a static member of this nest.
 177 // We know that k is an instance class in the same package and hence the
 178 // same classloader.
 179 bool InstanceKlass::has_nest_member(JavaThread* current, InstanceKlass* k) const {
 180   assert(!is_hidden(), "unexpected hidden class");
 181   if (_nest_members == nullptr || _nest_members == Universe::the_empty_short_array()) {
 182     if (log_is_enabled(Trace, class, nestmates)) {
 183       ResourceMark rm(current);
 184       log_trace(class, nestmates)("Checked nest membership of %s in non-nest-host class %s",
 185                                   k->external_name(), this->external_name());
 186     }
 187     return false;
 188   }
 189 
 190   if (log_is_enabled(Trace, class, nestmates)) {
 191     ResourceMark rm(current);
 192     log_trace(class, nestmates)("Checking nest membership of %s in %s",
 193                                 k->external_name(), this->external_name());
 194   }
 195 
 196   // Check for the named class in _nest_members.
 197   // We don't resolve, or load, any classes.
 198   for (int i = 0; i < _nest_members->length(); i++) {
 199     int cp_index = _nest_members->at(i);
 200     Symbol* name = _constants->klass_name_at(cp_index);
 201     if (name == k->name()) {
 202       log_trace(class, nestmates)("- named class found at nest_members[%d] => cp[%d]", i, cp_index);
 203       return true;
 204     }
 205   }
 206   log_trace(class, nestmates)("- class is NOT a nest member!");
 207   return false;
 208 }
 209 
 210 // Called to verify that k is a permitted subclass of this class
 211 bool InstanceKlass::has_as_permitted_subclass(const InstanceKlass* k) const {
 212   Thread* current = Thread::current();
 213   assert(k != nullptr, "sanity check");
 214   assert(_permitted_subclasses != nullptr && _permitted_subclasses != Universe::the_empty_short_array(),
 215          "unexpected empty _permitted_subclasses array");
 216 
 217   if (log_is_enabled(Trace, class, sealed)) {
 218     ResourceMark rm(current);
 219     log_trace(class, sealed)("Checking for permitted subclass of %s in %s",
 220                              k->external_name(), this->external_name());
 221   }
 222 
 223   // Check that the class and its super are in the same module.
 224   if (k->module() != this->module()) {
 225     ResourceMark rm(current);
 226     log_trace(class, sealed)("Check failed for same module of permitted subclass %s and sealed class %s",
 227                              k->external_name(), this->external_name());
 228     return false;
 229   }
 230 
 231   if (!k->is_public() && !is_same_class_package(k)) {
 232     ResourceMark rm(current);
 233     log_trace(class, sealed)("Check failed, subclass %s not public and not in the same package as sealed class %s",
 234                              k->external_name(), this->external_name());
 235     return false;
 236   }
 237 
 238   for (int i = 0; i < _permitted_subclasses->length(); i++) {
 239     int cp_index = _permitted_subclasses->at(i);
 240     Symbol* name = _constants->klass_name_at(cp_index);
 241     if (name == k->name()) {
 242       log_trace(class, sealed)("- Found it at permitted_subclasses[%d] => cp[%d]", i, cp_index);
 243       return true;
 244     }
 245   }
 246   log_trace(class, sealed)("- class is NOT a permitted subclass!");
 247   return false;
 248 }
 249 
 250 // Return nest-host class, resolving, validating and saving it if needed.
 251 // In cases where this is called from a thread that cannot do classloading
 252 // (such as a native JIT thread) then we simply return null, which in turn
 253 // causes the access check to return false. Such code will retry the access
 254 // from a more suitable environment later. Otherwise the _nest_host is always
 255 // set once this method returns.
 256 // Any errors from nest-host resolution must be preserved so they can be queried
 257 // from higher-level access checking code, and reported as part of access checking
 258 // exceptions.
 259 // VirtualMachineErrors are propagated with a null return.
 260 // Under any conditions where the _nest_host can be set to non-null the resulting
 261 // value of it and, if applicable, the nest host resolution/validation error,
 262 // are idempotent.
 263 InstanceKlass* InstanceKlass::nest_host(TRAPS) {
 264   InstanceKlass* nest_host_k = _nest_host;
 265   if (nest_host_k != nullptr) {
 266     return nest_host_k;
 267   }
 268 
 269   ResourceMark rm(THREAD);
 270 
 271   // need to resolve and save our nest-host class.
 272   if (_nest_host_index != 0) { // we have a real nest_host
 273     // Before trying to resolve check if we're in a suitable context
 274     bool can_resolve = THREAD->can_call_java();
 275     if (!can_resolve && !_constants->tag_at(_nest_host_index).is_klass()) {
 276       log_trace(class, nestmates)("Rejected resolution of nest-host of %s in unsuitable thread",
 277                                   this->external_name());
 278       return nullptr; // sentinel to say "try again from a different context"
 279     }
 280 
 281     log_trace(class, nestmates)("Resolving nest-host of %s using cp entry for %s",
 282                                 this->external_name(),
 283                                 _constants->klass_name_at(_nest_host_index)->as_C_string());
 284 
 285     Klass* k = _constants->klass_at(_nest_host_index, THREAD);
 286     if (HAS_PENDING_EXCEPTION) {
 287       if (PENDING_EXCEPTION->is_a(vmClasses::VirtualMachineError_klass())) {
 288         return nullptr; // propagate VMEs
 289       }
 290       stringStream ss;
 291       char* target_host_class = _constants->klass_name_at(_nest_host_index)->as_C_string();
 292       ss.print("Nest host resolution of %s with host %s failed: ",
 293                this->external_name(), target_host_class);
 294       java_lang_Throwable::print(PENDING_EXCEPTION, &ss);
 295       const char* msg = ss.as_string(true /* on C-heap */);
 296       constantPoolHandle cph(THREAD, constants());
 297       SystemDictionary::add_nest_host_error(cph, _nest_host_index, msg);
 298       CLEAR_PENDING_EXCEPTION;
 299 
 300       log_trace(class, nestmates)("%s", msg);
 301     } else {
 302       // A valid nest-host is an instance class in the current package that lists this
 303       // class as a nest member. If any of these conditions are not met the class is
 304       // its own nest-host.
 305       const char* error = nullptr;
 306 
 307       // JVMS 5.4.4 indicates package check comes first
 308       if (is_same_class_package(k)) {
 309         // Now check actual membership. We can't be a member if our "host" is
 310         // not an instance class.
 311         if (k->is_instance_klass()) {
 312           nest_host_k = InstanceKlass::cast(k);
 313           bool is_member = nest_host_k->has_nest_member(THREAD, this);
 314           if (is_member) {
 315             _nest_host = nest_host_k; // save resolved nest-host value
 316 
 317             log_trace(class, nestmates)("Resolved nest-host of %s to %s",
 318                                         this->external_name(), k->external_name());
 319             return nest_host_k;
 320           } else {
 321             error = "current type is not listed as a nest member";
 322           }
 323         } else {
 324           error = "host is not an instance class";
 325         }
 326       } else {
 327         error = "types are in different packages";
 328       }
 329 
 330       // something went wrong, so record what and log it
 331       {
 332         stringStream ss;
 333         ss.print("Type %s (loader: %s) is not a nest member of type %s (loader: %s): %s",
 334                  this->external_name(),
 335                  this->class_loader_data()->loader_name_and_id(),
 336                  k->external_name(),
 337                  k->class_loader_data()->loader_name_and_id(),
 338                  error);
 339         const char* msg = ss.as_string(true /* on C-heap */);
 340         constantPoolHandle cph(THREAD, constants());
 341         SystemDictionary::add_nest_host_error(cph, _nest_host_index, msg);
 342         log_trace(class, nestmates)("%s", msg);
 343       }
 344     }
 345   } else {
 346     log_trace(class, nestmates)("Type %s is not part of a nest: setting nest-host to self",
 347                                 this->external_name());
 348   }
 349 
 350   // Either not in an explicit nest, or else an error occurred, so
 351   // the nest-host is set to `this`. Any thread that sees this assignment
 352   // will also see any setting of nest_host_error(), if applicable.
 353   return (_nest_host = this);
 354 }
 355 
 356 // Dynamic nest member support: set this class's nest host to the given class.
 357 // This occurs as part of the class definition, as soon as the instanceKlass
 358 // has been created and doesn't require further resolution. The code:
 359 //    lookup().defineHiddenClass(bytes_for_X, NESTMATE);
 360 // results in:
 361 //    class_of_X.set_nest_host(lookup().lookupClass().getNestHost())
 362 // If it has an explicit _nest_host_index or _nest_members, these will be ignored.
 363 // We also know the "host" is a valid nest-host in the same package so we can
 364 // assert some of those facts.
 365 void InstanceKlass::set_nest_host(InstanceKlass* host) {
 366   assert(is_hidden(), "must be a hidden class");
 367   assert(host != nullptr, "null nest host specified");
 368   assert(_nest_host == nullptr, "current class has resolved nest-host");
 369   assert(nest_host_error() == nullptr, "unexpected nest host resolution error exists: %s",
 370          nest_host_error());
 371   assert((host->_nest_host == nullptr && host->_nest_host_index == 0) ||
 372          (host->_nest_host == host), "proposed host is not a valid nest-host");
 373   // Can't assert this as package is not set yet:
 374   // assert(is_same_class_package(host), "proposed host is in wrong package");
 375 
 376   if (log_is_enabled(Trace, class, nestmates)) {
 377     ResourceMark rm;
 378     const char* msg = "";
 379     // a hidden class does not expect a statically defined nest-host
 380     if (_nest_host_index > 0) {
 381       msg = "(the NestHost attribute in the current class is ignored)";
 382     } else if (_nest_members != nullptr && _nest_members != Universe::the_empty_short_array()) {
 383       msg = "(the NestMembers attribute in the current class is ignored)";
 384     }
 385     log_trace(class, nestmates)("Injected type %s into the nest of %s %s",
 386                                 this->external_name(),
 387                                 host->external_name(),
 388                                 msg);
 389   }
 390   // set dynamic nest host
 391   _nest_host = host;
 392   // Record dependency to keep nest host from being unloaded before this class.
 393   ClassLoaderData* this_key = class_loader_data();
 394   assert(this_key != nullptr, "sanity");
 395   this_key->record_dependency(host);
 396 }
 397 
 398 // check if 'this' and k are nestmates (same nest_host), or k is our nest_host,
 399 // or we are k's nest_host - all of which is covered by comparing the two
 400 // resolved_nest_hosts.
 401 // Any exceptions (i.e. VMEs) are propagated.
 402 bool InstanceKlass::has_nestmate_access_to(InstanceKlass* k, TRAPS) {
 403 
 404   assert(this != k, "this should be handled by higher-level code");
 405 
 406   // Per JVMS 5.4.4 we first resolve and validate the current class, then
 407   // the target class k.
 408 
 409   InstanceKlass* cur_host = nest_host(CHECK_false);
 410   if (cur_host == nullptr) {
 411     return false;
 412   }
 413 
 414   Klass* k_nest_host = k->nest_host(CHECK_false);
 415   if (k_nest_host == nullptr) {
 416     return false;
 417   }
 418 
 419   bool access = (cur_host == k_nest_host);
 420 
 421   ResourceMark rm(THREAD);
 422   log_trace(class, nestmates)("Class %s does %shave nestmate access to %s",
 423                               this->external_name(),
 424                               access ? "" : "NOT ",
 425                               k->external_name());
 426   return access;
 427 }
 428 
 429 const char* InstanceKlass::nest_host_error() {
 430   if (_nest_host_index == 0) {
 431     return nullptr;
 432   } else {
 433     constantPoolHandle cph(Thread::current(), constants());
 434     return SystemDictionary::find_nest_host_error(cph, (int)_nest_host_index);
 435   }
 436 }
 437 
 438 InstanceKlass* InstanceKlass::allocate_instance_klass(const ClassFileParser& parser, TRAPS) {
 439   const int size = InstanceKlass::size(parser.vtable_size(),
 440                                        parser.itable_size(),
 441                                        nonstatic_oop_map_size(parser.total_oop_map_count()),
 442                                        parser.is_interface());
 443 
 444   const Symbol* const class_name = parser.class_name();
 445   assert(class_name != nullptr, "invariant");
 446   ClassLoaderData* loader_data = parser.loader_data();
 447   assert(loader_data != nullptr, "invariant");
 448 
 449   InstanceKlass* ik;
 450 
 451   // Allocation
 452   if (parser.is_instance_ref_klass()) {
 453     // java.lang.ref.Reference
 454     ik = new (loader_data, size, THREAD) InstanceRefKlass(parser);
 455   } else if (class_name == vmSymbols::java_lang_Class()) {
 456     // mirror - java.lang.Class
 457     ik = new (loader_data, size, THREAD) InstanceMirrorKlass(parser);
 458   } else if (is_stack_chunk_class(class_name, loader_data)) {
 459     // stack chunk
 460     ik = new (loader_data, size, THREAD) InstanceStackChunkKlass(parser);
 461   } else if (is_class_loader(class_name, parser)) {
 462     // class loader - java.lang.ClassLoader
 463     ik = new (loader_data, size, THREAD) InstanceClassLoaderKlass(parser);
 464   } else {
 465     // normal
 466     ik = new (loader_data, size, THREAD) InstanceKlass(parser);
 467   }
 468 
 469   // Check for pending exception before adding to the loader data and incrementing
 470   // class count.  Can get OOM here.
 471   if (HAS_PENDING_EXCEPTION) {
 472     return nullptr;
 473   }
 474 
 475   return ik;
 476 }
 477 
 478 
 479 // copy method ordering from resource area to Metaspace
 480 void InstanceKlass::copy_method_ordering(const intArray* m, TRAPS) {
 481   if (m != nullptr) {
 482     // allocate a new array and copy contents (memcpy?)
 483     _method_ordering = MetadataFactory::new_array<int>(class_loader_data(), m->length(), CHECK);
 484     for (int i = 0; i < m->length(); i++) {
 485       _method_ordering->at_put(i, m->at(i));
 486     }
 487   } else {
 488     _method_ordering = Universe::the_empty_int_array();
 489   }
 490 }
 491 
 492 // create a new array of vtable_indices for default methods
 493 Array<int>* InstanceKlass::create_new_default_vtable_indices(int len, TRAPS) {
 494   Array<int>* vtable_indices = MetadataFactory::new_array<int>(class_loader_data(), len, CHECK_NULL);
 495   assert(default_vtable_indices() == nullptr, "only create once");
 496   set_default_vtable_indices(vtable_indices);
 497   return vtable_indices;
 498 }
 499 
 500 static Monitor* create_init_monitor(const char* name) {
 501   return new Monitor(Mutex::safepoint, name);
 502 }
 503 
 504 InstanceKlass::InstanceKlass() {
 505   assert(CDSConfig::is_dumping_static_archive() || CDSConfig::is_using_archive(), "only for CDS");
 506 }
 507 
 508 InstanceKlass::InstanceKlass(const ClassFileParser& parser, KlassKind kind, ReferenceType reference_type) :
 509   Klass(kind),
 510   _nest_members(nullptr),
 511   _nest_host(nullptr),
 512   _permitted_subclasses(nullptr),
 513   _record_components(nullptr),
 514   _static_field_size(parser.static_field_size()),
 515   _nonstatic_oop_map_size(nonstatic_oop_map_size(parser.total_oop_map_count())),
 516   _itable_len(parser.itable_size()),
 517   _nest_host_index(0),
 518   _init_state(allocated),
 519   _reference_type(reference_type),
 520   _init_monitor(create_init_monitor("InstanceKlassInitMonitor_lock")),
 521   _init_thread(nullptr)
 522 {
 523   set_vtable_length(parser.vtable_size());
 524   set_access_flags(parser.access_flags());
 525   if (parser.is_hidden()) set_is_hidden();
 526   set_layout_helper(Klass::instance_layout_helper(parser.layout_size(),
 527                                                     false));
 528 
 529   assert(nullptr == _methods, "underlying memory not zeroed?");
 530   assert(is_instance_klass(), "is layout incorrect?");
 531   assert(size_helper() == parser.layout_size(), "incorrect size_helper?");
 532 }
 533 
 534 void InstanceKlass::deallocate_methods(ClassLoaderData* loader_data,
 535                                        Array<Method*>* methods) {
 536   if (methods != nullptr && methods != Universe::the_empty_method_array() &&
 537       !methods->is_shared()) {
 538     for (int i = 0; i < methods->length(); i++) {
 539       Method* method = methods->at(i);
 540       if (method == nullptr) continue;  // maybe null if error processing
 541       // Only want to delete methods that are not executing for RedefineClasses.
 542       // The previous version will point to them so they're not totally dangling
 543       assert (!method->on_stack(), "shouldn't be called with methods on stack");
 544       MetadataFactory::free_metadata(loader_data, method);
 545     }
 546     MetadataFactory::free_array<Method*>(loader_data, methods);
 547   }
 548 }
 549 
 550 void InstanceKlass::deallocate_interfaces(ClassLoaderData* loader_data,
 551                                           const Klass* super_klass,
 552                                           Array<InstanceKlass*>* local_interfaces,
 553                                           Array<InstanceKlass*>* transitive_interfaces) {
 554   // Only deallocate transitive interfaces if not empty, same as super class
 555   // or same as local interfaces.  See code in parseClassFile.
 556   Array<InstanceKlass*>* ti = transitive_interfaces;
 557   if (ti != Universe::the_empty_instance_klass_array() && ti != local_interfaces) {
 558     // check that the interfaces don't come from super class
 559     Array<InstanceKlass*>* sti = (super_klass == nullptr) ? nullptr :
 560                     InstanceKlass::cast(super_klass)->transitive_interfaces();
 561     if (ti != sti && ti != nullptr && !ti->is_shared()) {
 562       MetadataFactory::free_array<InstanceKlass*>(loader_data, ti);
 563     }
 564   }
 565 
 566   // local interfaces can be empty
 567   if (local_interfaces != Universe::the_empty_instance_klass_array() &&
 568       local_interfaces != nullptr && !local_interfaces->is_shared()) {
 569     MetadataFactory::free_array<InstanceKlass*>(loader_data, local_interfaces);
 570   }
 571 }
 572 
 573 void InstanceKlass::deallocate_record_components(ClassLoaderData* loader_data,
 574                                                  Array<RecordComponent*>* record_components) {
 575   if (record_components != nullptr && !record_components->is_shared()) {
 576     for (int i = 0; i < record_components->length(); i++) {
 577       RecordComponent* record_component = record_components->at(i);
 578       MetadataFactory::free_metadata(loader_data, record_component);
 579     }
 580     MetadataFactory::free_array<RecordComponent*>(loader_data, record_components);
 581   }
 582 }
 583 
 584 // This function deallocates the metadata and C heap pointers that the
 585 // InstanceKlass points to.
 586 void InstanceKlass::deallocate_contents(ClassLoaderData* loader_data) {
 587   // Orphan the mirror first, CMS thinks it's still live.
 588   if (java_mirror() != nullptr) {
 589     java_lang_Class::set_klass(java_mirror(), nullptr);
 590   }
 591 
 592   // Also remove mirror from handles
 593   loader_data->remove_handle(_java_mirror);
 594 
 595   // Need to take this class off the class loader data list.
 596   loader_data->remove_class(this);
 597 
 598   // The array_klass for this class is created later, after error handling.
 599   // For class redefinition, we keep the original class so this scratch class
 600   // doesn't have an array class.  Either way, assert that there is nothing
 601   // to deallocate.
 602   assert(array_klasses() == nullptr, "array classes shouldn't be created for this class yet");
 603 
 604   // Release C heap allocated data that this points to, which includes
 605   // reference counting symbol names.
 606   // Can't release the constant pool or MethodData C heap data here because the constant
 607   // pool can be deallocated separately from the InstanceKlass for default methods and
 608   // redefine classes.  MethodData can also be released separately.
 609   release_C_heap_structures(/* release_sub_metadata */ false);
 610 
 611   deallocate_methods(loader_data, methods());
 612   set_methods(nullptr);
 613 
 614   deallocate_record_components(loader_data, record_components());
 615   set_record_components(nullptr);
 616 
 617   if (method_ordering() != nullptr &&
 618       method_ordering() != Universe::the_empty_int_array() &&
 619       !method_ordering()->is_shared()) {
 620     MetadataFactory::free_array<int>(loader_data, method_ordering());
 621   }
 622   set_method_ordering(nullptr);
 623 
 624   // default methods can be empty
 625   if (default_methods() != nullptr &&
 626       default_methods() != Universe::the_empty_method_array() &&
 627       !default_methods()->is_shared()) {
 628     MetadataFactory::free_array<Method*>(loader_data, default_methods());
 629   }
 630   // Do NOT deallocate the default methods, they are owned by superinterfaces.
 631   set_default_methods(nullptr);
 632 
 633   // default methods vtable indices can be empty
 634   if (default_vtable_indices() != nullptr &&
 635       !default_vtable_indices()->is_shared()) {
 636     MetadataFactory::free_array<int>(loader_data, default_vtable_indices());
 637   }
 638   set_default_vtable_indices(nullptr);
 639 
 640 
 641   // This array is in Klass, but remove it with the InstanceKlass since
 642   // this place would be the only caller and it can share memory with transitive
 643   // interfaces.
 644   if (secondary_supers() != nullptr &&
 645       secondary_supers() != Universe::the_empty_klass_array() &&
 646       // see comments in compute_secondary_supers about the following cast
 647       (address)(secondary_supers()) != (address)(transitive_interfaces()) &&
 648       !secondary_supers()->is_shared()) {
 649     MetadataFactory::free_array<Klass*>(loader_data, secondary_supers());
 650   }
 651   set_secondary_supers(nullptr);
 652 
 653   deallocate_interfaces(loader_data, super(), local_interfaces(), transitive_interfaces());
 654   set_transitive_interfaces(nullptr);
 655   set_local_interfaces(nullptr);
 656 
 657   if (fieldinfo_stream() != nullptr && !fieldinfo_stream()->is_shared()) {
 658     MetadataFactory::free_array<u1>(loader_data, fieldinfo_stream());
 659   }
 660   set_fieldinfo_stream(nullptr);
 661 
 662   if (fields_status() != nullptr && !fields_status()->is_shared()) {
 663     MetadataFactory::free_array<FieldStatus>(loader_data, fields_status());
 664   }
 665   set_fields_status(nullptr);
 666 
 667   // If a method from a redefined class is using this constant pool, don't
 668   // delete it, yet.  The new class's previous version will point to this.
 669   if (constants() != nullptr) {
 670     assert (!constants()->on_stack(), "shouldn't be called if anything is onstack");
 671     if (!constants()->is_shared()) {
 672       MetadataFactory::free_metadata(loader_data, constants());
 673     }
 674     // Delete any cached resolution errors for the constant pool
 675     SystemDictionary::delete_resolution_error(constants());
 676 
 677     set_constants(nullptr);
 678   }
 679 
 680   if (inner_classes() != nullptr &&
 681       inner_classes() != Universe::the_empty_short_array() &&
 682       !inner_classes()->is_shared()) {
 683     MetadataFactory::free_array<jushort>(loader_data, inner_classes());
 684   }
 685   set_inner_classes(nullptr);
 686 
 687   if (nest_members() != nullptr &&
 688       nest_members() != Universe::the_empty_short_array() &&
 689       !nest_members()->is_shared()) {
 690     MetadataFactory::free_array<jushort>(loader_data, nest_members());
 691   }
 692   set_nest_members(nullptr);
 693 
 694   if (permitted_subclasses() != nullptr &&
 695       permitted_subclasses() != Universe::the_empty_short_array() &&
 696       !permitted_subclasses()->is_shared()) {
 697     MetadataFactory::free_array<jushort>(loader_data, permitted_subclasses());
 698   }
 699   set_permitted_subclasses(nullptr);
 700 
 701   // We should deallocate the Annotations instance if it's not in shared spaces.
 702   if (annotations() != nullptr && !annotations()->is_shared()) {
 703     MetadataFactory::free_metadata(loader_data, annotations());
 704   }
 705   set_annotations(nullptr);
 706 
 707   SystemDictionaryShared::handle_class_unloading(this);
 708 
 709 #if INCLUDE_CDS_JAVA_HEAP
 710   if (CDSConfig::is_dumping_heap()) {
 711     HeapShared::remove_scratch_objects(this);
 712   }
 713 #endif
 714 }
 715 
 716 bool InstanceKlass::is_record() const {
 717   return _record_components != nullptr &&
 718          is_final() &&
 719          java_super() == vmClasses::Record_klass();
 720 }
 721 
 722 bool InstanceKlass::is_sealed() const {
 723   return _permitted_subclasses != nullptr &&
 724          _permitted_subclasses != Universe::the_empty_short_array();
 725 }
 726 
 727 bool InstanceKlass::should_be_initialized() const {
 728   return !is_initialized();
 729 }
 730 
 731 klassItable InstanceKlass::itable() const {
 732   return klassItable(const_cast<InstanceKlass*>(this));
 733 }
 734 
 735 // JVMTI spec thinks there are signers and protection domain in the
 736 // instanceKlass.  These accessors pretend these fields are there.
 737 // The hprof specification also thinks these fields are in InstanceKlass.
 738 oop InstanceKlass::protection_domain() const {
 739   // return the protection_domain from the mirror
 740   return java_lang_Class::protection_domain(java_mirror());
 741 }
 742 
 743 objArrayOop InstanceKlass::signers() const {
 744   // return the signers from the mirror
 745   return java_lang_Class::signers(java_mirror());
 746 }
 747 
 748 // See "The Virtual Machine Specification" section 2.16.5 for a detailed explanation of the class initialization
 749 // process. The step comments refers to the procedure described in that section.
 750 // Note: implementation moved to static method to expose the this pointer.
 751 void InstanceKlass::initialize(TRAPS) {
 752   if (this->should_be_initialized()) {
 753     initialize_impl(CHECK);
 754     // Note: at this point the class may be initialized
 755     //       OR it may be in the state of being initialized
 756     //       in case of recursive initialization!
 757   } else {
 758     assert(is_initialized(), "sanity check");
 759   }
 760 }
 761 
 762 
 763 bool InstanceKlass::verify_code(TRAPS) {
 764   // 1) Verify the bytecodes
 765   return Verifier::verify(this, should_verify_class(), THREAD);
 766 }
 767 
 768 void InstanceKlass::link_class(TRAPS) {
 769   assert(is_loaded(), "must be loaded");
 770   if (!is_linked()) {
 771     link_class_impl(CHECK);
 772   }
 773 }
 774 
 775 void InstanceKlass::check_link_state_and_wait(JavaThread* current) {
 776   MonitorLocker ml(current, _init_monitor);
 777 
 778   bool debug_logging_enabled = log_is_enabled(Debug, class, init);
 779 
 780   // Another thread is linking this class, wait.
 781   while (is_being_linked() && !is_init_thread(current)) {
 782     if (debug_logging_enabled) {
 783       ResourceMark rm(current);
 784       log_debug(class, init)("Thread \"%s\" waiting for linking of %s by thread \"%s\"",
 785                              current->name(), external_name(), init_thread_name());
 786     }
 787     ml.wait();
 788   }
 789 
 790   // This thread is recursively linking this class, continue
 791   if (is_being_linked() && is_init_thread(current)) {
 792     if (debug_logging_enabled) {
 793       ResourceMark rm(current);
 794       log_debug(class, init)("Thread \"%s\" recursively linking %s",
 795                              current->name(), external_name());
 796     }
 797     return;
 798   }
 799 
 800   // If this class wasn't linked already, set state to being_linked
 801   if (!is_linked()) {
 802     if (debug_logging_enabled) {
 803       ResourceMark rm(current);
 804       log_debug(class, init)("Thread \"%s\" linking %s",
 805                              current->name(), external_name());
 806     }
 807     set_init_state(being_linked);
 808     set_init_thread(current);
 809   } else {
 810     if (debug_logging_enabled) {
 811       ResourceMark rm(current);
 812       log_debug(class, init)("Thread \"%s\" found %s already linked",
 813                              current->name(), external_name());
 814       }
 815   }
 816 }
 817 
 818 // Called to verify that a class can link during initialization, without
 819 // throwing a VerifyError.
 820 bool InstanceKlass::link_class_or_fail(TRAPS) {
 821   assert(is_loaded(), "must be loaded");
 822   if (!is_linked()) {
 823     link_class_impl(CHECK_false);
 824   }
 825   return is_linked();
 826 }
 827 
 828 bool InstanceKlass::link_class_impl(TRAPS) {
 829   if (CDSConfig::is_dumping_static_archive() && SystemDictionaryShared::has_class_failed_verification(this)) {
 830     // This is for CDS static dump only -- we use the in_error_state to indicate that
 831     // the class has failed verification. Throwing the NoClassDefFoundError here is just
 832     // a convenient way to stop repeat attempts to verify the same (bad) class.
 833     //
 834     // Note that the NoClassDefFoundError is not part of the JLS, and should not be thrown
 835     // if we are executing Java code. This is not a problem for CDS dumping phase since
 836     // it doesn't execute any Java code.
 837     ResourceMark rm(THREAD);
 838     Exceptions::fthrow(THREAD_AND_LOCATION,
 839                        vmSymbols::java_lang_NoClassDefFoundError(),
 840                        "Class %s, or one of its supertypes, failed class initialization",
 841                        external_name());
 842     return false;
 843   }
 844   // return if already verified
 845   if (is_linked()) {
 846     return true;
 847   }
 848 
 849   // Timing
 850   // timer handles recursion
 851   JavaThread* jt = THREAD;
 852 
 853   // link super class before linking this class
 854   Klass* super_klass = super();
 855   if (super_klass != nullptr) {
 856     if (super_klass->is_interface()) {  // check if super class is an interface
 857       ResourceMark rm(THREAD);
 858       Exceptions::fthrow(
 859         THREAD_AND_LOCATION,
 860         vmSymbols::java_lang_IncompatibleClassChangeError(),
 861         "class %s has interface %s as super class",
 862         external_name(),
 863         super_klass->external_name()
 864       );
 865       return false;
 866     }
 867 
 868     InstanceKlass* ik_super = InstanceKlass::cast(super_klass);
 869     ik_super->link_class_impl(CHECK_false);
 870   }
 871 
 872   // link all interfaces implemented by this class before linking this class
 873   Array<InstanceKlass*>* interfaces = local_interfaces();
 874   int num_interfaces = interfaces->length();
 875   for (int index = 0; index < num_interfaces; index++) {
 876     InstanceKlass* interk = interfaces->at(index);
 877     interk->link_class_impl(CHECK_false);
 878   }
 879 
 880   // in case the class is linked in the process of linking its superclasses
 881   if (is_linked()) {
 882     return true;
 883   }
 884 
 885   // trace only the link time for this klass that includes
 886   // the verification time
 887   PerfClassTraceTime vmtimer(ClassLoader::perf_class_link_time(),
 888                              ClassLoader::perf_class_link_selftime(),
 889                              ClassLoader::perf_classes_linked(),
 890                              jt->get_thread_stat()->perf_recursion_counts_addr(),
 891                              jt->get_thread_stat()->perf_timers_addr(),
 892                              PerfClassTraceTime::CLASS_LINK);
 893 
 894   // verification & rewriting
 895   {
 896     LockLinkState init_lock(this, jt);
 897 
 898     // rewritten will have been set if loader constraint error found
 899     // on an earlier link attempt
 900     // don't verify or rewrite if already rewritten
 901     //
 902 
 903     if (!is_linked()) {
 904       if (!is_rewritten()) {
 905         if (is_shared()) {
 906           assert(!verified_at_dump_time(), "must be");
 907         }
 908         {
 909           bool verify_ok = verify_code(THREAD);
 910           if (!verify_ok) {
 911             return false;
 912           }
 913         }
 914 
 915         // Just in case a side-effect of verify linked this class already
 916         // (which can sometimes happen since the verifier loads classes
 917         // using custom class loaders, which are free to initialize things)
 918         if (is_linked()) {
 919           return true;
 920         }
 921 
 922         // also sets rewritten
 923         rewrite_class(CHECK_false);
 924       } else if (is_shared()) {
 925         SystemDictionaryShared::check_verification_constraints(this, CHECK_false);
 926       }
 927 
 928       // relocate jsrs and link methods after they are all rewritten
 929       link_methods(CHECK_false);
 930 
 931       // Initialize the vtable and interface table after
 932       // methods have been rewritten since rewrite may
 933       // fabricate new Method*s.
 934       // also does loader constraint checking
 935       //
 936       // initialize_vtable and initialize_itable need to be rerun
 937       // for a shared class if
 938       // 1) the class is loaded by custom class loader or
 939       // 2) the class is loaded by built-in class loader but failed to add archived loader constraints or
 940       // 3) the class was not verified during dump time
 941       bool need_init_table = true;
 942       if (is_shared() && verified_at_dump_time() &&
 943           SystemDictionaryShared::check_linking_constraints(THREAD, this)) {
 944         need_init_table = false;
 945       }
 946       if (need_init_table) {
 947         vtable().initialize_vtable_and_check_constraints(CHECK_false);
 948         itable().initialize_itable_and_check_constraints(CHECK_false);
 949       }
 950 #ifdef ASSERT
 951       vtable().verify(tty, true);
 952       // In case itable verification is ever added.
 953       // itable().verify(tty, true);
 954 #endif
 955       set_initialization_state_and_notify(linked, THREAD);
 956       if (JvmtiExport::should_post_class_prepare()) {
 957         JvmtiExport::post_class_prepare(THREAD, this);
 958       }
 959     }
 960   }
 961   return true;
 962 }
 963 
 964 // Rewrite the byte codes of all of the methods of a class.
 965 // The rewriter must be called exactly once. Rewriting must happen after
 966 // verification but before the first method of the class is executed.
 967 void InstanceKlass::rewrite_class(TRAPS) {
 968   assert(is_loaded(), "must be loaded");
 969   if (is_rewritten()) {
 970     assert(is_shared(), "rewriting an unshared class?");
 971     return;
 972   }
 973   Rewriter::rewrite(this, CHECK);
 974   set_rewritten();
 975 }
 976 
 977 // Now relocate and link method entry points after class is rewritten.
 978 // This is outside is_rewritten flag. In case of an exception, it can be
 979 // executed more than once.
 980 void InstanceKlass::link_methods(TRAPS) {
 981   int len = methods()->length();
 982   for (int i = len-1; i >= 0; i--) {
 983     methodHandle m(THREAD, methods()->at(i));
 984 
 985     // Set up method entry points for compiler and interpreter    .
 986     m->link_method(m, CHECK);
 987   }
 988 }
 989 
 990 // Eagerly initialize superinterfaces that declare default methods (concrete instance: any access)
 991 void InstanceKlass::initialize_super_interfaces(TRAPS) {
 992   assert (has_nonstatic_concrete_methods(), "caller should have checked this");
 993   for (int i = 0; i < local_interfaces()->length(); ++i) {
 994     InstanceKlass* ik = local_interfaces()->at(i);
 995 
 996     // Initialization is depth first search ie. we start with top of the inheritance tree
 997     // has_nonstatic_concrete_methods drives searching superinterfaces since it
 998     // means has_nonstatic_concrete_methods in its superinterface hierarchy
 999     if (ik->has_nonstatic_concrete_methods()) {
1000       ik->initialize_super_interfaces(CHECK);
1001     }
1002 
1003     // Only initialize() interfaces that "declare" concrete methods.
1004     if (ik->should_be_initialized() && ik->declares_nonstatic_concrete_methods()) {
1005       ik->initialize(CHECK);
1006     }
1007   }
1008 }
1009 
1010 using InitializationErrorTable = ResourceHashtable<const InstanceKlass*, OopHandle, 107, AnyObj::C_HEAP, mtClass>;
1011 static InitializationErrorTable* _initialization_error_table;
1012 
1013 void InstanceKlass::add_initialization_error(JavaThread* current, Handle exception) {
1014   // Create the same exception with a message indicating the thread name,
1015   // and the StackTraceElements.
1016   Handle init_error = java_lang_Throwable::create_initialization_error(current, exception);
1017   ResourceMark rm(current);
1018   if (init_error.is_null()) {
1019     log_trace(class, init)("Unable to create the desired initialization error for class %s", external_name());
1020 
1021     // We failed to create the new exception, most likely due to either out-of-memory or
1022     // a stackoverflow error. If the original exception was either of those then we save
1023     // the shared, pre-allocated, stackless, instance of that exception.
1024     if (exception->klass() == vmClasses::StackOverflowError_klass()) {
1025       log_debug(class, init)("Using shared StackOverflowError as initialization error for class %s", external_name());
1026       init_error = Handle(current, Universe::class_init_stack_overflow_error());
1027     } else if (exception->klass() == vmClasses::OutOfMemoryError_klass()) {
1028       log_debug(class, init)("Using shared OutOfMemoryError as initialization error for class %s", external_name());
1029       init_error = Handle(current, Universe::class_init_out_of_memory_error());
1030     } else {
1031       return;
1032     }
1033   }
1034 
1035   MutexLocker ml(current, ClassInitError_lock);
1036   OopHandle elem = OopHandle(Universe::vm_global(), init_error());
1037   bool created;
1038   if (_initialization_error_table == nullptr) {
1039     _initialization_error_table = new (mtClass) InitializationErrorTable();
1040   }
1041   _initialization_error_table->put_if_absent(this, elem, &created);
1042   assert(created, "Initialization is single threaded");
1043   log_trace(class, init)("Initialization error added for class %s", external_name());
1044 }
1045 
1046 oop InstanceKlass::get_initialization_error(JavaThread* current) {
1047   MutexLocker ml(current, ClassInitError_lock);
1048   if (_initialization_error_table == nullptr) {
1049     return nullptr;
1050   }
1051   OopHandle* h = _initialization_error_table->get(this);
1052   return (h != nullptr) ? h->resolve() : nullptr;
1053 }
1054 
1055 // Need to remove entries for unloaded classes.
1056 void InstanceKlass::clean_initialization_error_table() {
1057   struct InitErrorTableCleaner {
1058     bool do_entry(const InstanceKlass* ik, OopHandle h) {
1059       if (!ik->is_loader_alive()) {
1060         h.release(Universe::vm_global());
1061         return true;
1062       } else {
1063         return false;
1064       }
1065     }
1066   };
1067 
1068   assert_locked_or_safepoint(ClassInitError_lock);
1069   InitErrorTableCleaner cleaner;
1070   if (_initialization_error_table != nullptr) {
1071     _initialization_error_table->unlink(&cleaner);
1072   }
1073 }
1074 
1075 void InstanceKlass::initialize_impl(TRAPS) {
1076   HandleMark hm(THREAD);
1077 
1078   // Make sure klass is linked (verified) before initialization
1079   // A class could already be verified, since it has been reflected upon.
1080   link_class(CHECK);
1081 
1082   DTRACE_CLASSINIT_PROBE(required, -1);
1083 
1084   bool wait = false;
1085   bool throw_error = false;
1086 
1087   JavaThread* jt = THREAD;
1088 
1089   bool debug_logging_enabled = log_is_enabled(Debug, class, init);
1090 
1091   // refer to the JVM book page 47 for description of steps
1092   // Step 1
1093   {
1094     MonitorLocker ml(jt, _init_monitor);
1095 
1096     // Step 2
1097     while (is_being_initialized() && !is_init_thread(jt)) {
1098       if (debug_logging_enabled) {
1099         ResourceMark rm(jt);
1100         log_debug(class, init)("Thread \"%s\" waiting for initialization of %s by thread \"%s\"",
1101                                jt->name(), external_name(), init_thread_name());
1102       }
1103 
1104       wait = true;
1105       jt->set_class_to_be_initialized(this);
1106       ml.wait();
1107       jt->set_class_to_be_initialized(nullptr);
1108     }
1109 
1110     // Step 3
1111     if (is_being_initialized() && is_init_thread(jt)) {
1112       if (debug_logging_enabled) {
1113         ResourceMark rm(jt);
1114         log_debug(class, init)("Thread \"%s\" recursively initializing %s",
1115                                jt->name(), external_name());
1116       }
1117       DTRACE_CLASSINIT_PROBE_WAIT(recursive, -1, wait);
1118       return;
1119     }
1120 
1121     // Step 4
1122     if (is_initialized()) {
1123       if (debug_logging_enabled) {
1124         ResourceMark rm(jt);
1125         log_debug(class, init)("Thread \"%s\" found %s already initialized",
1126                                jt->name(), external_name());
1127       }
1128       DTRACE_CLASSINIT_PROBE_WAIT(concurrent, -1, wait);
1129       return;
1130     }
1131 
1132     // Step 5
1133     if (is_in_error_state()) {
1134       if (debug_logging_enabled) {
1135         ResourceMark rm(jt);
1136         log_debug(class, init)("Thread \"%s\" found %s is in error state",
1137                                jt->name(), external_name());
1138       }
1139       throw_error = true;
1140     } else {
1141 
1142       // Step 6
1143       set_init_state(being_initialized);
1144       set_init_thread(jt);
1145       if (debug_logging_enabled) {
1146         ResourceMark rm(jt);
1147         log_debug(class, init)("Thread \"%s\" is initializing %s",
1148                                jt->name(), external_name());
1149       }
1150     }
1151   }
1152 
1153   // Throw error outside lock
1154   if (throw_error) {
1155     DTRACE_CLASSINIT_PROBE_WAIT(erroneous, -1, wait);
1156     ResourceMark rm(THREAD);
1157     Handle cause(THREAD, get_initialization_error(THREAD));
1158 
1159     stringStream ss;
1160     ss.print("Could not initialize class %s", external_name());
1161     if (cause.is_null()) {
1162       THROW_MSG(vmSymbols::java_lang_NoClassDefFoundError(), ss.as_string());
1163     } else {
1164       THROW_MSG_CAUSE(vmSymbols::java_lang_NoClassDefFoundError(),
1165                       ss.as_string(), cause);
1166     }
1167   }
1168 
1169   // Step 7
1170   // Next, if C is a class rather than an interface, initialize it's super class and super
1171   // interfaces.
1172   if (!is_interface()) {
1173     Klass* super_klass = super();
1174     if (super_klass != nullptr && super_klass->should_be_initialized()) {
1175       super_klass->initialize(THREAD);
1176     }
1177     // If C implements any interface that declares a non-static, concrete method,
1178     // the initialization of C triggers initialization of its super interfaces.
1179     // Only need to recurse if has_nonstatic_concrete_methods which includes declaring and
1180     // having a superinterface that declares, non-static, concrete methods
1181     if (!HAS_PENDING_EXCEPTION && has_nonstatic_concrete_methods()) {
1182       initialize_super_interfaces(THREAD);
1183     }
1184 
1185     // If any exceptions, complete abruptly, throwing the same exception as above.
1186     if (HAS_PENDING_EXCEPTION) {
1187       Handle e(THREAD, PENDING_EXCEPTION);
1188       CLEAR_PENDING_EXCEPTION;
1189       {
1190         EXCEPTION_MARK;
1191         add_initialization_error(THREAD, e);
1192         // Locks object, set state, and notify all waiting threads
1193         set_initialization_state_and_notify(initialization_error, THREAD);
1194         CLEAR_PENDING_EXCEPTION;
1195       }
1196       DTRACE_CLASSINIT_PROBE_WAIT(super__failed, -1, wait);
1197       THROW_OOP(e());
1198     }
1199   }
1200 
1201 
1202   // Step 8
1203   {
1204     DTRACE_CLASSINIT_PROBE_WAIT(clinit, -1, wait);
1205     if (class_initializer() != nullptr) {
1206       // Timer includes any side effects of class initialization (resolution,
1207       // etc), but not recursive entry into call_class_initializer().
1208       PerfClassTraceTime timer(ClassLoader::perf_class_init_time(),
1209                                ClassLoader::perf_class_init_selftime(),
1210                                ClassLoader::perf_classes_inited(),
1211                                jt->get_thread_stat()->perf_recursion_counts_addr(),
1212                                jt->get_thread_stat()->perf_timers_addr(),
1213                                PerfClassTraceTime::CLASS_CLINIT);
1214       call_class_initializer(THREAD);
1215     } else {
1216       // The elapsed time is so small it's not worth counting.
1217       if (UsePerfData) {
1218         ClassLoader::perf_classes_inited()->inc();
1219       }
1220       call_class_initializer(THREAD);
1221     }
1222   }
1223 
1224   // Step 9
1225   if (!HAS_PENDING_EXCEPTION) {
1226     set_initialization_state_and_notify(fully_initialized, THREAD);
1227     debug_only(vtable().verify(tty, true);)
1228   }
1229   else {
1230     // Step 10 and 11
1231     Handle e(THREAD, PENDING_EXCEPTION);
1232     CLEAR_PENDING_EXCEPTION;
1233     // JVMTI has already reported the pending exception
1234     // JVMTI internal flag reset is needed in order to report ExceptionInInitializerError
1235     JvmtiExport::clear_detected_exception(jt);
1236     {
1237       EXCEPTION_MARK;
1238       add_initialization_error(THREAD, e);
1239       set_initialization_state_and_notify(initialization_error, THREAD);
1240       CLEAR_PENDING_EXCEPTION;   // ignore any exception thrown, class initialization error is thrown below
1241       // JVMTI has already reported the pending exception
1242       // JVMTI internal flag reset is needed in order to report ExceptionInInitializerError
1243       JvmtiExport::clear_detected_exception(jt);
1244     }
1245     DTRACE_CLASSINIT_PROBE_WAIT(error, -1, wait);
1246     if (e->is_a(vmClasses::Error_klass())) {
1247       THROW_OOP(e());
1248     } else {
1249       JavaCallArguments args(e);
1250       THROW_ARG(vmSymbols::java_lang_ExceptionInInitializerError(),
1251                 vmSymbols::throwable_void_signature(),
1252                 &args);
1253     }
1254   }
1255   DTRACE_CLASSINIT_PROBE_WAIT(end, -1, wait);
1256 }
1257 
1258 
1259 void InstanceKlass::set_initialization_state_and_notify(ClassState state, JavaThread* current) {
1260   MonitorLocker ml(current, _init_monitor);
1261 
1262   if (state == linked && UseVtableBasedCHA && Universe::is_fully_initialized()) {
1263     DeoptimizationScope deopt_scope;
1264     {
1265       // Now mark all code that assumes the class is not linked.
1266       // Set state under the Compile_lock also.
1267       MutexLocker ml(current, Compile_lock);
1268 
1269       set_init_thread(nullptr); // reset _init_thread before changing _init_state
1270       set_init_state(state);
1271 
1272       CodeCache::mark_dependents_on(&deopt_scope, this);
1273     }
1274     // Perform the deopt handshake outside Compile_lock.
1275     deopt_scope.deoptimize_marked();
1276   } else {
1277     set_init_thread(nullptr); // reset _init_thread before changing _init_state
1278     set_init_state(state);
1279   }
1280   ml.notify_all();
1281 }
1282 
1283 // Update hierarchy. This is done before the new klass has been added to the SystemDictionary. The Compile_lock
1284 // is grabbed, to ensure that the compiler is not using the class hierarchy.
1285 void InstanceKlass::add_to_hierarchy(JavaThread* current) {
1286   assert(!SafepointSynchronize::is_at_safepoint(), "must NOT be at safepoint");
1287 
1288   // In case we are not using CHA based vtables we need to make sure the loaded
1289   // deopt is completed before anyone links this class.
1290   // Linking is done with _init_monitor held, by loading and deopting with it
1291   // held we make sure the deopt is completed before linking.
1292   if (!UseVtableBasedCHA) {
1293     init_monitor()->lock();
1294   }
1295 
1296   DeoptimizationScope deopt_scope;
1297   {
1298     MutexLocker ml(current, Compile_lock);
1299 
1300     set_init_state(InstanceKlass::loaded);
1301     // make sure init_state store is already done.
1302     // The compiler reads the hierarchy outside of the Compile_lock.
1303     // Access ordering is used to add to hierarchy.
1304 
1305     // Link into hierarchy.
1306     append_to_sibling_list();                    // add to superklass/sibling list
1307     process_interfaces();                        // handle all "implements" declarations
1308 
1309     // Now mark all code that depended on old class hierarchy.
1310     // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1311     if (Universe::is_fully_initialized()) {
1312       CodeCache::mark_dependents_on(&deopt_scope, this);
1313     }
1314   }
1315   // Perform the deopt handshake outside Compile_lock.
1316   deopt_scope.deoptimize_marked();
1317 
1318   if (!UseVtableBasedCHA) {
1319     init_monitor()->unlock();
1320   }
1321 }
1322 
1323 InstanceKlass* InstanceKlass::implementor() const {
1324   InstanceKlass* volatile* ik = adr_implementor();
1325   if (ik == nullptr) {
1326     return nullptr;
1327   } else {
1328     // This load races with inserts, and therefore needs acquire.
1329     InstanceKlass* ikls = Atomic::load_acquire(ik);
1330     if (ikls != nullptr && !ikls->is_loader_alive()) {
1331       return nullptr;  // don't return unloaded class
1332     } else {
1333       return ikls;
1334     }
1335   }
1336 }
1337 
1338 
1339 void InstanceKlass::set_implementor(InstanceKlass* ik) {
1340   assert_locked_or_safepoint(Compile_lock);
1341   assert(is_interface(), "not interface");
1342   InstanceKlass* volatile* addr = adr_implementor();
1343   assert(addr != nullptr, "null addr");
1344   if (addr != nullptr) {
1345     Atomic::release_store(addr, ik);
1346   }
1347 }
1348 
1349 int  InstanceKlass::nof_implementors() const {
1350   InstanceKlass* ik = implementor();
1351   if (ik == nullptr) {
1352     return 0;
1353   } else if (ik != this) {
1354     return 1;
1355   } else {
1356     return 2;
1357   }
1358 }
1359 
1360 // The embedded _implementor field can only record one implementor.
1361 // When there are more than one implementors, the _implementor field
1362 // is set to the interface Klass* itself. Following are the possible
1363 // values for the _implementor field:
1364 //   null                  - no implementor
1365 //   implementor Klass*    - one implementor
1366 //   self                  - more than one implementor
1367 //
1368 // The _implementor field only exists for interfaces.
1369 void InstanceKlass::add_implementor(InstanceKlass* ik) {
1370   if (Universe::is_fully_initialized()) {
1371     assert_lock_strong(Compile_lock);
1372   }
1373   assert(is_interface(), "not interface");
1374   // Filter out my subinterfaces.
1375   // (Note: Interfaces are never on the subklass list.)
1376   if (ik->is_interface()) return;
1377 
1378   // Filter out subclasses whose supers already implement me.
1379   // (Note: CHA must walk subclasses of direct implementors
1380   // in order to locate indirect implementors.)
1381   InstanceKlass* super_ik = ik->java_super();
1382   if (super_ik != nullptr && super_ik->implements_interface(this))
1383     // We only need to check one immediate superclass, since the
1384     // implements_interface query looks at transitive_interfaces.
1385     // Any supers of the super have the same (or fewer) transitive_interfaces.
1386     return;
1387 
1388   InstanceKlass* iklass = implementor();
1389   if (iklass == nullptr) {
1390     set_implementor(ik);
1391   } else if (iklass != this && iklass != ik) {
1392     // There is already an implementor. Use itself as an indicator of
1393     // more than one implementors.
1394     set_implementor(this);
1395   }
1396 
1397   // The implementor also implements the transitive_interfaces
1398   for (int index = 0; index < local_interfaces()->length(); index++) {
1399     local_interfaces()->at(index)->add_implementor(ik);
1400   }
1401 }
1402 
1403 void InstanceKlass::init_implementor() {
1404   if (is_interface()) {
1405     set_implementor(nullptr);
1406   }
1407 }
1408 
1409 
1410 void InstanceKlass::process_interfaces() {
1411   // link this class into the implementors list of every interface it implements
1412   for (int i = local_interfaces()->length() - 1; i >= 0; i--) {
1413     assert(local_interfaces()->at(i)->is_klass(), "must be a klass");
1414     InstanceKlass* interf = local_interfaces()->at(i);
1415     assert(interf->is_interface(), "expected interface");
1416     interf->add_implementor(this);
1417   }
1418 }
1419 
1420 bool InstanceKlass::can_be_primary_super_slow() const {
1421   if (is_interface())
1422     return false;
1423   else
1424     return Klass::can_be_primary_super_slow();
1425 }
1426 
1427 GrowableArray<Klass*>* InstanceKlass::compute_secondary_supers(int num_extra_slots,
1428                                                                Array<InstanceKlass*>* transitive_interfaces) {
1429   // The secondaries are the implemented interfaces.
1430   // We need the cast because Array<Klass*> is NOT a supertype of Array<InstanceKlass*>,
1431   // (but it's safe to do here because we won't write into _secondary_supers from this point on).
1432   Array<Klass*>* interfaces = (Array<Klass*>*)(address)transitive_interfaces;
1433   int num_secondaries = num_extra_slots + interfaces->length();
1434   if (num_secondaries == 0) {
1435     // Must share this for correct bootstrapping!
1436     set_secondary_supers(Universe::the_empty_klass_array(), Universe::the_empty_klass_bitmap());
1437     return nullptr;
1438   } else if (num_extra_slots == 0) {
1439     // The secondary super list is exactly the same as the transitive interfaces, so
1440     // let's use it instead of making a copy.
1441     // Redefine classes has to be careful not to delete this!
1442     if (!UseSecondarySupersTable) {
1443       set_secondary_supers(interfaces);
1444       return nullptr;
1445     } else if (num_extra_slots == 0 && interfaces->length() <= 1) {
1446       // We will reuse the transitive interfaces list if we're certain
1447       // it's in hash order.
1448       uintx bitmap = compute_secondary_supers_bitmap(interfaces);
1449       set_secondary_supers(interfaces, bitmap);
1450       return nullptr;
1451     }
1452     // ... fall through if that didn't work.
1453   }
1454   // Copy transitive interfaces to a temporary growable array to be constructed
1455   // into the secondary super list with extra slots.
1456   GrowableArray<Klass*>* secondaries = new GrowableArray<Klass*>(interfaces->length());
1457   for (int i = 0; i < interfaces->length(); i++) {
1458     secondaries->push(interfaces->at(i));
1459   }
1460   return secondaries;
1461 }
1462 
1463 bool InstanceKlass::implements_interface(Klass* k) const {
1464   if (this == k) return true;
1465   assert(k->is_interface(), "should be an interface class");
1466   for (int i = 0; i < transitive_interfaces()->length(); i++) {
1467     if (transitive_interfaces()->at(i) == k) {
1468       return true;
1469     }
1470   }
1471   return false;
1472 }
1473 
1474 bool InstanceKlass::is_same_or_direct_interface(Klass *k) const {
1475   // Verify direct super interface
1476   if (this == k) return true;
1477   assert(k->is_interface(), "should be an interface class");
1478   for (int i = 0; i < local_interfaces()->length(); i++) {
1479     if (local_interfaces()->at(i) == k) {
1480       return true;
1481     }
1482   }
1483   return false;
1484 }
1485 
1486 objArrayOop InstanceKlass::allocate_objArray(int n, int length, TRAPS) {
1487   check_array_allocation_length(length, arrayOopDesc::max_array_length(T_OBJECT), CHECK_NULL);
1488   size_t size = objArrayOopDesc::object_size(length);
1489   ArrayKlass* ak = array_klass(n, CHECK_NULL);
1490   objArrayOop o = (objArrayOop)Universe::heap()->array_allocate(ak, size, length,
1491                                                                 /* do_zero */ true, CHECK_NULL);
1492   return o;
1493 }
1494 
1495 instanceOop InstanceKlass::register_finalizer(instanceOop i, TRAPS) {
1496   if (TraceFinalizerRegistration) {
1497     tty->print("Registered ");
1498     i->print_value_on(tty);
1499     tty->print_cr(" (" PTR_FORMAT ") as finalizable", p2i(i));
1500   }
1501   instanceHandle h_i(THREAD, i);
1502   // Pass the handle as argument, JavaCalls::call expects oop as jobjects
1503   JavaValue result(T_VOID);
1504   JavaCallArguments args(h_i);
1505   methodHandle mh(THREAD, Universe::finalizer_register_method());
1506   JavaCalls::call(&result, mh, &args, CHECK_NULL);
1507   MANAGEMENT_ONLY(FinalizerService::on_register(h_i(), THREAD);)
1508   return h_i();
1509 }
1510 
1511 instanceOop InstanceKlass::allocate_instance(TRAPS) {
1512   assert(!is_abstract() && !is_interface(), "Should not create this object");
1513   size_t size = size_helper();  // Query before forming handle.
1514   return (instanceOop)Universe::heap()->obj_allocate(this, size, CHECK_NULL);
1515 }
1516 
1517 instanceOop InstanceKlass::allocate_instance(oop java_class, TRAPS) {
1518   Klass* k = java_lang_Class::as_Klass(java_class);
1519   if (k == nullptr) {
1520     ResourceMark rm(THREAD);
1521     THROW_(vmSymbols::java_lang_InstantiationException(), nullptr);
1522   }
1523   InstanceKlass* ik = cast(k);
1524   ik->check_valid_for_instantiation(false, CHECK_NULL);
1525   ik->initialize(CHECK_NULL);
1526   return ik->allocate_instance(THREAD);
1527 }
1528 
1529 instanceHandle InstanceKlass::allocate_instance_handle(TRAPS) {
1530   return instanceHandle(THREAD, allocate_instance(THREAD));
1531 }
1532 
1533 void InstanceKlass::check_valid_for_instantiation(bool throwError, TRAPS) {
1534   if (is_interface() || is_abstract()) {
1535     ResourceMark rm(THREAD);
1536     THROW_MSG(throwError ? vmSymbols::java_lang_InstantiationError()
1537               : vmSymbols::java_lang_InstantiationException(), external_name());
1538   }
1539   if (this == vmClasses::Class_klass()) {
1540     ResourceMark rm(THREAD);
1541     THROW_MSG(throwError ? vmSymbols::java_lang_IllegalAccessError()
1542               : vmSymbols::java_lang_IllegalAccessException(), external_name());
1543   }
1544 }
1545 
1546 ArrayKlass* InstanceKlass::array_klass(int n, TRAPS) {
1547   // Need load-acquire for lock-free read
1548   if (array_klasses_acquire() == nullptr) {
1549 
1550     // Recursively lock array allocation
1551     RecursiveLocker rl(MultiArray_lock, THREAD);
1552 
1553     // Check if another thread created the array klass while we were waiting for the lock.
1554     if (array_klasses() == nullptr) {
1555       ObjArrayKlass* k = ObjArrayKlass::allocate_objArray_klass(class_loader_data(), 1, this, CHECK_NULL);
1556       // use 'release' to pair with lock-free load
1557       release_set_array_klasses(k);
1558     }
1559   }
1560 
1561   // array_klasses() will always be set at this point
1562   ObjArrayKlass* ak = array_klasses();
1563   assert(ak != nullptr, "should be set");
1564   return ak->array_klass(n, THREAD);
1565 }
1566 
1567 ArrayKlass* InstanceKlass::array_klass_or_null(int n) {
1568   // Need load-acquire for lock-free read
1569   ObjArrayKlass* oak = array_klasses_acquire();
1570   if (oak == nullptr) {
1571     return nullptr;
1572   } else {
1573     return oak->array_klass_or_null(n);
1574   }
1575 }
1576 
1577 ArrayKlass* InstanceKlass::array_klass(TRAPS) {
1578   return array_klass(1, THREAD);
1579 }
1580 
1581 ArrayKlass* InstanceKlass::array_klass_or_null() {
1582   return array_klass_or_null(1);
1583 }
1584 
1585 static int call_class_initializer_counter = 0;   // for debugging
1586 
1587 Method* InstanceKlass::class_initializer() const {
1588   Method* clinit = find_method(
1589       vmSymbols::class_initializer_name(), vmSymbols::void_method_signature());
1590   if (clinit != nullptr && clinit->has_valid_initializer_flags()) {
1591     return clinit;
1592   }
1593   return nullptr;
1594 }
1595 
1596 void InstanceKlass::call_class_initializer(TRAPS) {
1597   if (ReplayCompiles &&
1598       (ReplaySuppressInitializers == 1 ||
1599        (ReplaySuppressInitializers >= 2 && class_loader() != nullptr))) {
1600     // Hide the existence of the initializer for the purpose of replaying the compile
1601     return;
1602   }
1603 
1604 #if INCLUDE_CDS
1605   // This is needed to ensure the consistency of the archived heap objects.
1606   if (has_archived_enum_objs()) {
1607     assert(is_shared(), "must be");
1608     bool initialized = HeapShared::initialize_enum_klass(this, CHECK);
1609     if (initialized) {
1610       return;
1611     }
1612   }
1613 #endif
1614 
1615   methodHandle h_method(THREAD, class_initializer());
1616   assert(!is_initialized(), "we cannot initialize twice");
1617   LogTarget(Info, class, init) lt;
1618   if (lt.is_enabled()) {
1619     ResourceMark rm(THREAD);
1620     LogStream ls(lt);
1621     ls.print("%d Initializing ", call_class_initializer_counter++);
1622     name()->print_value_on(&ls);
1623     ls.print_cr("%s (" PTR_FORMAT ") by thread \"%s\"",
1624                 h_method() == nullptr ? "(no method)" : "", p2i(this),
1625                 THREAD->name());
1626   }
1627   if (h_method() != nullptr) {
1628     JavaCallArguments args; // No arguments
1629     JavaValue result(T_VOID);
1630     JavaCalls::call(&result, h_method, &args, CHECK); // Static call (no args)
1631   }
1632 }
1633 
1634 
1635 void InstanceKlass::mask_for(const methodHandle& method, int bci,
1636   InterpreterOopMap* entry_for) {
1637   // Lazily create the _oop_map_cache at first request.
1638   // Load_acquire is needed to safely get instance published with CAS by another thread.
1639   OopMapCache* oop_map_cache = Atomic::load_acquire(&_oop_map_cache);
1640   if (oop_map_cache == nullptr) {
1641     // Try to install new instance atomically.
1642     oop_map_cache = new OopMapCache();
1643     OopMapCache* other = Atomic::cmpxchg(&_oop_map_cache, (OopMapCache*)nullptr, oop_map_cache);
1644     if (other != nullptr) {
1645       // Someone else managed to install before us, ditch local copy and use the existing one.
1646       delete oop_map_cache;
1647       oop_map_cache = other;
1648     }
1649   }
1650   // _oop_map_cache is constant after init; lookup below does its own locking.
1651   oop_map_cache->lookup(method, bci, entry_for);
1652 }
1653 
1654 bool InstanceKlass::contains_field_offset(int offset) {
1655   fieldDescriptor fd;
1656   return find_field_from_offset(offset, false, &fd);
1657 }
1658 
1659 FieldInfo InstanceKlass::field(int index) const {
1660   for (AllFieldStream fs(this); !fs.done(); fs.next()) {
1661     if (fs.index() == index) {
1662       return fs.to_FieldInfo();
1663     }
1664   }
1665   fatal("Field not found");
1666   return FieldInfo();
1667 }
1668 
1669 bool InstanceKlass::find_local_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
1670   for (JavaFieldStream fs(this); !fs.done(); fs.next()) {
1671     Symbol* f_name = fs.name();
1672     Symbol* f_sig  = fs.signature();
1673     if (f_name == name && f_sig == sig) {
1674       fd->reinitialize(const_cast<InstanceKlass*>(this), fs.index());
1675       return true;
1676     }
1677   }
1678   return false;
1679 }
1680 
1681 
1682 Klass* InstanceKlass::find_interface_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
1683   const int n = local_interfaces()->length();
1684   for (int i = 0; i < n; i++) {
1685     Klass* intf1 = local_interfaces()->at(i);
1686     assert(intf1->is_interface(), "just checking type");
1687     // search for field in current interface
1688     if (InstanceKlass::cast(intf1)->find_local_field(name, sig, fd)) {
1689       assert(fd->is_static(), "interface field must be static");
1690       return intf1;
1691     }
1692     // search for field in direct superinterfaces
1693     Klass* intf2 = InstanceKlass::cast(intf1)->find_interface_field(name, sig, fd);
1694     if (intf2 != nullptr) return intf2;
1695   }
1696   // otherwise field lookup fails
1697   return nullptr;
1698 }
1699 
1700 
1701 Klass* InstanceKlass::find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
1702   // search order according to newest JVM spec (5.4.3.2, p.167).
1703   // 1) search for field in current klass
1704   if (find_local_field(name, sig, fd)) {
1705     return const_cast<InstanceKlass*>(this);
1706   }
1707   // 2) search for field recursively in direct superinterfaces
1708   { Klass* intf = find_interface_field(name, sig, fd);
1709     if (intf != nullptr) return intf;
1710   }
1711   // 3) apply field lookup recursively if superclass exists
1712   { Klass* supr = super();
1713     if (supr != nullptr) return InstanceKlass::cast(supr)->find_field(name, sig, fd);
1714   }
1715   // 4) otherwise field lookup fails
1716   return nullptr;
1717 }
1718 
1719 
1720 Klass* InstanceKlass::find_field(Symbol* name, Symbol* sig, bool is_static, fieldDescriptor* fd) const {
1721   // search order according to newest JVM spec (5.4.3.2, p.167).
1722   // 1) search for field in current klass
1723   if (find_local_field(name, sig, fd)) {
1724     if (fd->is_static() == is_static) return const_cast<InstanceKlass*>(this);
1725   }
1726   // 2) search for field recursively in direct superinterfaces
1727   if (is_static) {
1728     Klass* intf = find_interface_field(name, sig, fd);
1729     if (intf != nullptr) return intf;
1730   }
1731   // 3) apply field lookup recursively if superclass exists
1732   { Klass* supr = super();
1733     if (supr != nullptr) return InstanceKlass::cast(supr)->find_field(name, sig, is_static, fd);
1734   }
1735   // 4) otherwise field lookup fails
1736   return nullptr;
1737 }
1738 
1739 
1740 bool InstanceKlass::find_local_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const {
1741   for (JavaFieldStream fs(this); !fs.done(); fs.next()) {
1742     if (fs.offset() == offset) {
1743       fd->reinitialize(const_cast<InstanceKlass*>(this), fs.index());
1744       if (fd->is_static() == is_static) return true;
1745     }
1746   }
1747   return false;
1748 }
1749 
1750 
1751 bool InstanceKlass::find_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const {
1752   Klass* klass = const_cast<InstanceKlass*>(this);
1753   while (klass != nullptr) {
1754     if (InstanceKlass::cast(klass)->find_local_field_from_offset(offset, is_static, fd)) {
1755       return true;
1756     }
1757     klass = klass->super();
1758   }
1759   return false;
1760 }
1761 
1762 
1763 void InstanceKlass::methods_do(void f(Method* method)) {
1764   // Methods aren't stable until they are loaded.  This can be read outside
1765   // a lock through the ClassLoaderData for profiling
1766   // Redefined scratch classes are on the list and need to be cleaned
1767   if (!is_loaded() && !is_scratch_class()) {
1768     return;
1769   }
1770 
1771   int len = methods()->length();
1772   for (int index = 0; index < len; index++) {
1773     Method* m = methods()->at(index);
1774     assert(m->is_method(), "must be method");
1775     f(m);
1776   }
1777 }
1778 
1779 
1780 void InstanceKlass::do_local_static_fields(FieldClosure* cl) {
1781   for (JavaFieldStream fs(this); !fs.done(); fs.next()) {
1782     if (fs.access_flags().is_static()) {
1783       fieldDescriptor& fd = fs.field_descriptor();
1784       cl->do_field(&fd);
1785     }
1786   }
1787 }
1788 
1789 
1790 void InstanceKlass::do_local_static_fields(void f(fieldDescriptor*, Handle, TRAPS), Handle mirror, TRAPS) {
1791   for (JavaFieldStream fs(this); !fs.done(); fs.next()) {
1792     if (fs.access_flags().is_static()) {
1793       fieldDescriptor& fd = fs.field_descriptor();
1794       f(&fd, mirror, CHECK);
1795     }
1796   }
1797 }
1798 
1799 void InstanceKlass::do_nonstatic_fields(FieldClosure* cl) {
1800   InstanceKlass* super = superklass();
1801   if (super != nullptr) {
1802     super->do_nonstatic_fields(cl);
1803   }
1804   fieldDescriptor fd;
1805   int length = java_fields_count();
1806   for (int i = 0; i < length; i += 1) {
1807     fd.reinitialize(this, i);
1808     if (!fd.is_static()) {
1809       cl->do_field(&fd);
1810     }
1811   }
1812 }
1813 
1814 // first in Pair is offset, second is index.
1815 static int compare_fields_by_offset(Pair<int,int>* a, Pair<int,int>* b) {
1816   return a->first - b->first;
1817 }
1818 
1819 void InstanceKlass::print_nonstatic_fields(FieldClosure* cl) {
1820   InstanceKlass* super = superklass();
1821   if (super != nullptr) {
1822     super->print_nonstatic_fields(cl);
1823   }
1824   ResourceMark rm;
1825   fieldDescriptor fd;
1826   // In DebugInfo nonstatic fields are sorted by offset.
1827   GrowableArray<Pair<int,int> > fields_sorted;
1828   int i = 0;
1829   for (AllFieldStream fs(this); !fs.done(); fs.next()) {
1830     if (!fs.access_flags().is_static()) {
1831       fd = fs.field_descriptor();
1832       Pair<int,int> f(fs.offset(), fs.index());
1833       fields_sorted.push(f);
1834       i++;
1835     }
1836   }
1837   if (i > 0) {
1838     int length = i;
1839     assert(length == fields_sorted.length(), "duh");
1840     fields_sorted.sort(compare_fields_by_offset);
1841     for (int i = 0; i < length; i++) {
1842       fd.reinitialize(this, fields_sorted.at(i).second);
1843       assert(!fd.is_static() && fd.offset() == fields_sorted.at(i).first, "only nonstatic fields");
1844       cl->do_field(&fd);
1845     }
1846   }
1847 }
1848 
1849 #ifdef ASSERT
1850 static int linear_search(const Array<Method*>* methods,
1851                          const Symbol* name,
1852                          const Symbol* signature) {
1853   const int len = methods->length();
1854   for (int index = 0; index < len; index++) {
1855     const Method* const m = methods->at(index);
1856     assert(m->is_method(), "must be method");
1857     if (m->signature() == signature && m->name() == name) {
1858        return index;
1859     }
1860   }
1861   return -1;
1862 }
1863 #endif
1864 
1865 bool InstanceKlass::_disable_method_binary_search = false;
1866 
1867 NOINLINE int linear_search(const Array<Method*>* methods, const Symbol* name) {
1868   int len = methods->length();
1869   int l = 0;
1870   int h = len - 1;
1871   while (l <= h) {
1872     Method* m = methods->at(l);
1873     if (m->name() == name) {
1874       return l;
1875     }
1876     l++;
1877   }
1878   return -1;
1879 }
1880 
1881 inline int InstanceKlass::quick_search(const Array<Method*>* methods, const Symbol* name) {
1882   if (_disable_method_binary_search) {
1883     assert(CDSConfig::is_dumping_dynamic_archive(), "must be");
1884     // At the final stage of dynamic dumping, the methods array may not be sorted
1885     // by ascending addresses of their names, so we can't use binary search anymore.
1886     // However, methods with the same name are still laid out consecutively inside the
1887     // methods array, so let's look for the first one that matches.
1888     return linear_search(methods, name);
1889   }
1890 
1891   int len = methods->length();
1892   int l = 0;
1893   int h = len - 1;
1894 
1895   // methods are sorted by ascending addresses of their names, so do binary search
1896   while (l <= h) {
1897     int mid = (l + h) >> 1;
1898     Method* m = methods->at(mid);
1899     assert(m->is_method(), "must be method");
1900     int res = m->name()->fast_compare(name);
1901     if (res == 0) {
1902       return mid;
1903     } else if (res < 0) {
1904       l = mid + 1;
1905     } else {
1906       h = mid - 1;
1907     }
1908   }
1909   return -1;
1910 }
1911 
1912 // find_method looks up the name/signature in the local methods array
1913 Method* InstanceKlass::find_method(const Symbol* name,
1914                                    const Symbol* signature) const {
1915   return find_method_impl(name, signature,
1916                           OverpassLookupMode::find,
1917                           StaticLookupMode::find,
1918                           PrivateLookupMode::find);
1919 }
1920 
1921 Method* InstanceKlass::find_method_impl(const Symbol* name,
1922                                         const Symbol* signature,
1923                                         OverpassLookupMode overpass_mode,
1924                                         StaticLookupMode static_mode,
1925                                         PrivateLookupMode private_mode) const {
1926   return InstanceKlass::find_method_impl(methods(),
1927                                          name,
1928                                          signature,
1929                                          overpass_mode,
1930                                          static_mode,
1931                                          private_mode);
1932 }
1933 
1934 // find_instance_method looks up the name/signature in the local methods array
1935 // and skips over static methods
1936 Method* InstanceKlass::find_instance_method(const Array<Method*>* methods,
1937                                             const Symbol* name,
1938                                             const Symbol* signature,
1939                                             PrivateLookupMode private_mode) {
1940   Method* const meth = InstanceKlass::find_method_impl(methods,
1941                                                  name,
1942                                                  signature,
1943                                                  OverpassLookupMode::find,
1944                                                  StaticLookupMode::skip,
1945                                                  private_mode);
1946   assert(((meth == nullptr) || !meth->is_static()),
1947     "find_instance_method should have skipped statics");
1948   return meth;
1949 }
1950 
1951 // find_instance_method looks up the name/signature in the local methods array
1952 // and skips over static methods
1953 Method* InstanceKlass::find_instance_method(const Symbol* name,
1954                                             const Symbol* signature,
1955                                             PrivateLookupMode private_mode) const {
1956   return InstanceKlass::find_instance_method(methods(), name, signature, private_mode);
1957 }
1958 
1959 // Find looks up the name/signature in the local methods array
1960 // and filters on the overpass, static and private flags
1961 // This returns the first one found
1962 // note that the local methods array can have up to one overpass, one static
1963 // and one instance (private or not) with the same name/signature
1964 Method* InstanceKlass::find_local_method(const Symbol* name,
1965                                          const Symbol* signature,
1966                                          OverpassLookupMode overpass_mode,
1967                                          StaticLookupMode static_mode,
1968                                          PrivateLookupMode private_mode) const {
1969   return InstanceKlass::find_method_impl(methods(),
1970                                          name,
1971                                          signature,
1972                                          overpass_mode,
1973                                          static_mode,
1974                                          private_mode);
1975 }
1976 
1977 // Find looks up the name/signature in the local methods array
1978 // and filters on the overpass, static and private flags
1979 // This returns the first one found
1980 // note that the local methods array can have up to one overpass, one static
1981 // and one instance (private or not) with the same name/signature
1982 Method* InstanceKlass::find_local_method(const Array<Method*>* methods,
1983                                          const Symbol* name,
1984                                          const Symbol* signature,
1985                                          OverpassLookupMode overpass_mode,
1986                                          StaticLookupMode static_mode,
1987                                          PrivateLookupMode private_mode) {
1988   return InstanceKlass::find_method_impl(methods,
1989                                          name,
1990                                          signature,
1991                                          overpass_mode,
1992                                          static_mode,
1993                                          private_mode);
1994 }
1995 
1996 Method* InstanceKlass::find_method(const Array<Method*>* methods,
1997                                    const Symbol* name,
1998                                    const Symbol* signature) {
1999   return InstanceKlass::find_method_impl(methods,
2000                                          name,
2001                                          signature,
2002                                          OverpassLookupMode::find,
2003                                          StaticLookupMode::find,
2004                                          PrivateLookupMode::find);
2005 }
2006 
2007 Method* InstanceKlass::find_method_impl(const Array<Method*>* methods,
2008                                         const Symbol* name,
2009                                         const Symbol* signature,
2010                                         OverpassLookupMode overpass_mode,
2011                                         StaticLookupMode static_mode,
2012                                         PrivateLookupMode private_mode) {
2013   int hit = find_method_index(methods, name, signature, overpass_mode, static_mode, private_mode);
2014   return hit >= 0 ? methods->at(hit): nullptr;
2015 }
2016 
2017 // true if method matches signature and conforms to skipping_X conditions.
2018 static bool method_matches(const Method* m,
2019                            const Symbol* signature,
2020                            bool skipping_overpass,
2021                            bool skipping_static,
2022                            bool skipping_private) {
2023   return ((m->signature() == signature) &&
2024     (!skipping_overpass || !m->is_overpass()) &&
2025     (!skipping_static || !m->is_static()) &&
2026     (!skipping_private || !m->is_private()));
2027 }
2028 
2029 // Used directly for default_methods to find the index into the
2030 // default_vtable_indices, and indirectly by find_method
2031 // find_method_index looks in the local methods array to return the index
2032 // of the matching name/signature. If, overpass methods are being ignored,
2033 // the search continues to find a potential non-overpass match.  This capability
2034 // is important during method resolution to prefer a static method, for example,
2035 // over an overpass method.
2036 // There is the possibility in any _method's array to have the same name/signature
2037 // for a static method, an overpass method and a local instance method
2038 // To correctly catch a given method, the search criteria may need
2039 // to explicitly skip the other two. For local instance methods, it
2040 // is often necessary to skip private methods
2041 int InstanceKlass::find_method_index(const Array<Method*>* methods,
2042                                      const Symbol* name,
2043                                      const Symbol* signature,
2044                                      OverpassLookupMode overpass_mode,
2045                                      StaticLookupMode static_mode,
2046                                      PrivateLookupMode private_mode) {
2047   const bool skipping_overpass = (overpass_mode == OverpassLookupMode::skip);
2048   const bool skipping_static = (static_mode == StaticLookupMode::skip);
2049   const bool skipping_private = (private_mode == PrivateLookupMode::skip);
2050   const int hit = quick_search(methods, name);
2051   if (hit != -1) {
2052     const Method* const m = methods->at(hit);
2053 
2054     // Do linear search to find matching signature.  First, quick check
2055     // for common case, ignoring overpasses if requested.
2056     if (method_matches(m, signature, skipping_overpass, skipping_static, skipping_private)) {
2057       return hit;
2058     }
2059 
2060     // search downwards through overloaded methods
2061     int i;
2062     for (i = hit - 1; i >= 0; --i) {
2063         const Method* const m = methods->at(i);
2064         assert(m->is_method(), "must be method");
2065         if (m->name() != name) {
2066           break;
2067         }
2068         if (method_matches(m, signature, skipping_overpass, skipping_static, skipping_private)) {
2069           return i;
2070         }
2071     }
2072     // search upwards
2073     for (i = hit + 1; i < methods->length(); ++i) {
2074         const Method* const m = methods->at(i);
2075         assert(m->is_method(), "must be method");
2076         if (m->name() != name) {
2077           break;
2078         }
2079         if (method_matches(m, signature, skipping_overpass, skipping_static, skipping_private)) {
2080           return i;
2081         }
2082     }
2083     // not found
2084 #ifdef ASSERT
2085     const int index = (skipping_overpass || skipping_static || skipping_private) ? -1 :
2086       linear_search(methods, name, signature);
2087     assert(-1 == index, "binary search should have found entry %d", index);
2088 #endif
2089   }
2090   return -1;
2091 }
2092 
2093 int InstanceKlass::find_method_by_name(const Symbol* name, int* end) const {
2094   return find_method_by_name(methods(), name, end);
2095 }
2096 
2097 int InstanceKlass::find_method_by_name(const Array<Method*>* methods,
2098                                        const Symbol* name,
2099                                        int* end_ptr) {
2100   assert(end_ptr != nullptr, "just checking");
2101   int start = quick_search(methods, name);
2102   int end = start + 1;
2103   if (start != -1) {
2104     while (start - 1 >= 0 && (methods->at(start - 1))->name() == name) --start;
2105     while (end < methods->length() && (methods->at(end))->name() == name) ++end;
2106     *end_ptr = end;
2107     return start;
2108   }
2109   return -1;
2110 }
2111 
2112 // uncached_lookup_method searches both the local class methods array and all
2113 // superclasses methods arrays, skipping any overpass methods in superclasses,
2114 // and possibly skipping private methods.
2115 Method* InstanceKlass::uncached_lookup_method(const Symbol* name,
2116                                               const Symbol* signature,
2117                                               OverpassLookupMode overpass_mode,
2118                                               PrivateLookupMode private_mode) const {
2119   OverpassLookupMode overpass_local_mode = overpass_mode;
2120   const Klass* klass = this;
2121   while (klass != nullptr) {
2122     Method* const method = InstanceKlass::cast(klass)->find_method_impl(name,
2123                                                                         signature,
2124                                                                         overpass_local_mode,
2125                                                                         StaticLookupMode::find,
2126                                                                         private_mode);
2127     if (method != nullptr) {
2128       return method;
2129     }
2130     klass = klass->super();
2131     overpass_local_mode = OverpassLookupMode::skip;   // Always ignore overpass methods in superclasses
2132   }
2133   return nullptr;
2134 }
2135 
2136 #ifdef ASSERT
2137 // search through class hierarchy and return true if this class or
2138 // one of the superclasses was redefined
2139 bool InstanceKlass::has_redefined_this_or_super() const {
2140   const Klass* klass = this;
2141   while (klass != nullptr) {
2142     if (InstanceKlass::cast(klass)->has_been_redefined()) {
2143       return true;
2144     }
2145     klass = klass->super();
2146   }
2147   return false;
2148 }
2149 #endif
2150 
2151 // lookup a method in the default methods list then in all transitive interfaces
2152 // Do NOT return private or static methods
2153 Method* InstanceKlass::lookup_method_in_ordered_interfaces(Symbol* name,
2154                                                          Symbol* signature) const {
2155   Method* m = nullptr;
2156   if (default_methods() != nullptr) {
2157     m = find_method(default_methods(), name, signature);
2158   }
2159   // Look up interfaces
2160   if (m == nullptr) {
2161     m = lookup_method_in_all_interfaces(name, signature, DefaultsLookupMode::find);
2162   }
2163   return m;
2164 }
2165 
2166 // lookup a method in all the interfaces that this class implements
2167 // Do NOT return private or static methods, new in JDK8 which are not externally visible
2168 // They should only be found in the initial InterfaceMethodRef
2169 Method* InstanceKlass::lookup_method_in_all_interfaces(Symbol* name,
2170                                                        Symbol* signature,
2171                                                        DefaultsLookupMode defaults_mode) const {
2172   Array<InstanceKlass*>* all_ifs = transitive_interfaces();
2173   int num_ifs = all_ifs->length();
2174   InstanceKlass *ik = nullptr;
2175   for (int i = 0; i < num_ifs; i++) {
2176     ik = all_ifs->at(i);
2177     Method* m = ik->lookup_method(name, signature);
2178     if (m != nullptr && m->is_public() && !m->is_static() &&
2179         ((defaults_mode != DefaultsLookupMode::skip) || !m->is_default_method())) {
2180       return m;
2181     }
2182   }
2183   return nullptr;
2184 }
2185 
2186 PrintClassClosure::PrintClassClosure(outputStream* st, bool verbose)
2187   :_st(st), _verbose(verbose) {
2188   ResourceMark rm;
2189   _st->print("%-18s  ", "KlassAddr");
2190   _st->print("%-4s  ", "Size");
2191   _st->print("%-20s  ", "State");
2192   _st->print("%-7s  ", "Flags");
2193   _st->print("%-5s  ", "ClassName");
2194   _st->cr();
2195 }
2196 
2197 void PrintClassClosure::do_klass(Klass* k)  {
2198   ResourceMark rm;
2199   // klass pointer
2200   _st->print(PTR_FORMAT "  ", p2i(k));
2201   // klass size
2202   _st->print("%4d  ", k->size());
2203   // initialization state
2204   if (k->is_instance_klass()) {
2205     _st->print("%-20s  ",InstanceKlass::cast(k)->init_state_name());
2206   } else {
2207     _st->print("%-20s  ","");
2208   }
2209   // misc flags(Changes should synced with ClassesDCmd::ClassesDCmd help doc)
2210   char buf[10];
2211   int i = 0;
2212   if (k->has_finalizer()) buf[i++] = 'F';
2213   if (k->is_instance_klass()) {
2214     InstanceKlass* ik = InstanceKlass::cast(k);
2215     if (ik->has_final_method()) buf[i++] = 'f';
2216     if (ik->is_rewritten()) buf[i++] = 'W';
2217     if (ik->is_contended()) buf[i++] = 'C';
2218     if (ik->has_been_redefined()) buf[i++] = 'R';
2219     if (ik->is_shared()) buf[i++] = 'S';
2220   }
2221   buf[i++] = '\0';
2222   _st->print("%-7s  ", buf);
2223   // klass name
2224   _st->print("%-5s  ", k->external_name());
2225   // end
2226   _st->cr();
2227   if (_verbose) {
2228     k->print_on(_st);
2229   }
2230 }
2231 
2232 /* jni_id_for for jfieldIds only */
2233 JNIid* InstanceKlass::jni_id_for(int offset) {
2234   MutexLocker ml(JfieldIdCreation_lock);
2235   JNIid* probe = jni_ids() == nullptr ? nullptr : jni_ids()->find(offset);
2236   if (probe == nullptr) {
2237     // Allocate new static field identifier
2238     probe = new JNIid(this, offset, jni_ids());
2239     set_jni_ids(probe);
2240   }
2241   return probe;
2242 }
2243 
2244 u2 InstanceKlass::enclosing_method_data(int offset) const {
2245   const Array<jushort>* const inner_class_list = inner_classes();
2246   if (inner_class_list == nullptr) {
2247     return 0;
2248   }
2249   const int length = inner_class_list->length();
2250   if (length % inner_class_next_offset == 0) {
2251     return 0;
2252   }
2253   const int index = length - enclosing_method_attribute_size;
2254   assert(offset < enclosing_method_attribute_size, "invalid offset");
2255   return inner_class_list->at(index + offset);
2256 }
2257 
2258 void InstanceKlass::set_enclosing_method_indices(u2 class_index,
2259                                                  u2 method_index) {
2260   Array<jushort>* inner_class_list = inner_classes();
2261   assert (inner_class_list != nullptr, "_inner_classes list is not set up");
2262   int length = inner_class_list->length();
2263   if (length % inner_class_next_offset == enclosing_method_attribute_size) {
2264     int index = length - enclosing_method_attribute_size;
2265     inner_class_list->at_put(
2266       index + enclosing_method_class_index_offset, class_index);
2267     inner_class_list->at_put(
2268       index + enclosing_method_method_index_offset, method_index);
2269   }
2270 }
2271 
2272 jmethodID InstanceKlass::update_jmethod_id(jmethodID* jmeths, Method* method, int idnum) {
2273   if (method->is_old() && !method->is_obsolete()) {
2274     // If the method passed in is old (but not obsolete), use the current version.
2275     method = method_with_idnum((int)idnum);
2276     assert(method != nullptr, "old and but not obsolete, so should exist");
2277   }
2278   jmethodID new_id = Method::make_jmethod_id(class_loader_data(), method);
2279   Atomic::release_store(&jmeths[idnum + 1], new_id);
2280   return new_id;
2281 }
2282 
2283 // Lookup or create a jmethodID.
2284 // This code is called by the VMThread and JavaThreads so the
2285 // locking has to be done very carefully to avoid deadlocks
2286 // and/or other cache consistency problems.
2287 //
2288 jmethodID InstanceKlass::get_jmethod_id(const methodHandle& method_h) {
2289   Method* method = method_h();
2290   int idnum = method->method_idnum();
2291   jmethodID* jmeths = methods_jmethod_ids_acquire();
2292 
2293   // We use a double-check locking idiom here because this cache is
2294   // performance sensitive. In the normal system, this cache only
2295   // transitions from null to non-null which is safe because we use
2296   // release_set_methods_jmethod_ids() to advertise the new cache.
2297   // A partially constructed cache should never be seen by a racing
2298   // thread. We also use release_store() to save a new jmethodID
2299   // in the cache so a partially constructed jmethodID should never be
2300   // seen either. Cache reads of existing jmethodIDs proceed without a
2301   // lock, but cache writes of a new jmethodID requires uniqueness and
2302   // creation of the cache itself requires no leaks so a lock is
2303   // acquired in those two cases.
2304   //
2305   // If the RedefineClasses() API has been used, then this cache grows
2306   // in the redefinition safepoint.
2307 
2308   if (jmeths == nullptr) {
2309     MutexLocker ml(JmethodIdCreation_lock, Mutex::_no_safepoint_check_flag);
2310     jmeths = methods_jmethod_ids_acquire();
2311     // Still null?
2312     if (jmeths == nullptr) {
2313       size_t size = idnum_allocated_count();
2314       assert(size > (size_t)idnum, "should already have space");
2315       jmeths = NEW_C_HEAP_ARRAY(jmethodID, size + 1, mtClass);
2316       memset(jmeths, 0, (size + 1) * sizeof(jmethodID));
2317       // cache size is stored in element[0], other elements offset by one
2318       jmeths[0] = (jmethodID)size;
2319       jmethodID new_id = update_jmethod_id(jmeths, method, idnum);
2320 
2321       // publish jmeths
2322       release_set_methods_jmethod_ids(jmeths);
2323       return new_id;
2324     }
2325   }
2326 
2327   jmethodID id = Atomic::load_acquire(&jmeths[idnum + 1]);
2328   if (id == nullptr) {
2329     MutexLocker ml(JmethodIdCreation_lock, Mutex::_no_safepoint_check_flag);
2330     id = jmeths[idnum + 1];
2331     // Still null?
2332     if (id == nullptr) {
2333       return update_jmethod_id(jmeths, method, idnum);
2334     }
2335   }
2336   return id;
2337 }
2338 
2339 void InstanceKlass::update_methods_jmethod_cache() {
2340   assert(SafepointSynchronize::is_at_safepoint(), "only called at safepoint");
2341   jmethodID* cache = _methods_jmethod_ids;
2342   if (cache != nullptr) {
2343     size_t size = idnum_allocated_count();
2344     size_t old_size = (size_t)cache[0];
2345     if (old_size < size + 1) {
2346       // Allocate a larger one and copy entries to the new one.
2347       // They've already been updated to point to new methods where applicable (i.e., not obsolete).
2348       jmethodID* new_cache = NEW_C_HEAP_ARRAY(jmethodID, size + 1, mtClass);
2349       memset(new_cache, 0, (size + 1) * sizeof(jmethodID));
2350       // The cache size is stored in element[0]; the other elements are offset by one.
2351       new_cache[0] = (jmethodID)size;
2352 
2353       for (int i = 1; i <= (int)old_size; i++) {
2354         new_cache[i] = cache[i];
2355       }
2356       _methods_jmethod_ids = new_cache;
2357       FREE_C_HEAP_ARRAY(jmethodID, cache);
2358     }
2359   }
2360 }
2361 
2362 // Figure out how many jmethodIDs haven't been allocated, and make
2363 // sure space for them is pre-allocated.  This makes getting all
2364 // method ids much, much faster with classes with more than 8
2365 // methods, and has a *substantial* effect on performance with jvmti
2366 // code that loads all jmethodIDs for all classes.
2367 void InstanceKlass::ensure_space_for_methodids(int start_offset) {
2368   int new_jmeths = 0;
2369   int length = methods()->length();
2370   for (int index = start_offset; index < length; index++) {
2371     Method* m = methods()->at(index);
2372     jmethodID id = m->find_jmethod_id_or_null();
2373     if (id == nullptr) {
2374       new_jmeths++;
2375     }
2376   }
2377   if (new_jmeths != 0) {
2378     Method::ensure_jmethod_ids(class_loader_data(), new_jmeths);
2379   }
2380 }
2381 
2382 // Lookup a jmethodID, null if not found.  Do no blocking, no allocations, no handles
2383 jmethodID InstanceKlass::jmethod_id_or_null(Method* method) {
2384   int idnum = method->method_idnum();
2385   jmethodID* jmeths = methods_jmethod_ids_acquire();
2386   return (jmeths != nullptr) ? jmeths[idnum + 1] : nullptr;
2387 }
2388 
2389 inline DependencyContext InstanceKlass::dependencies() {
2390   DependencyContext dep_context(&_dep_context, &_dep_context_last_cleaned);
2391   return dep_context;
2392 }
2393 
2394 void InstanceKlass::mark_dependent_nmethods(DeoptimizationScope* deopt_scope, KlassDepChange& changes) {
2395   dependencies().mark_dependent_nmethods(deopt_scope, changes);
2396 }
2397 
2398 void InstanceKlass::add_dependent_nmethod(nmethod* nm) {
2399   dependencies().add_dependent_nmethod(nm);
2400 }
2401 
2402 void InstanceKlass::clean_dependency_context() {
2403   dependencies().clean_unloading_dependents();
2404 }
2405 
2406 #ifndef PRODUCT
2407 void InstanceKlass::print_dependent_nmethods(bool verbose) {
2408   dependencies().print_dependent_nmethods(verbose);
2409 }
2410 
2411 bool InstanceKlass::is_dependent_nmethod(nmethod* nm) {
2412   return dependencies().is_dependent_nmethod(nm);
2413 }
2414 #endif //PRODUCT
2415 
2416 void InstanceKlass::clean_weak_instanceklass_links() {
2417   clean_implementors_list();
2418   clean_method_data();
2419 }
2420 
2421 void InstanceKlass::clean_implementors_list() {
2422   assert(is_loader_alive(), "this klass should be live");
2423   if (is_interface()) {
2424     assert (ClassUnloading, "only called for ClassUnloading");
2425     for (;;) {
2426       // Use load_acquire due to competing with inserts
2427       InstanceKlass* volatile* iklass = adr_implementor();
2428       assert(iklass != nullptr, "Klass must not be null");
2429       InstanceKlass* impl = Atomic::load_acquire(iklass);
2430       if (impl != nullptr && !impl->is_loader_alive()) {
2431         // null this field, might be an unloaded instance klass or null
2432         if (Atomic::cmpxchg(iklass, impl, (InstanceKlass*)nullptr) == impl) {
2433           // Successfully unlinking implementor.
2434           if (log_is_enabled(Trace, class, unload)) {
2435             ResourceMark rm;
2436             log_trace(class, unload)("unlinking class (implementor): %s", impl->external_name());
2437           }
2438           return;
2439         }
2440       } else {
2441         return;
2442       }
2443     }
2444   }
2445 }
2446 
2447 void InstanceKlass::clean_method_data() {
2448   for (int m = 0; m < methods()->length(); m++) {
2449     MethodData* mdo = methods()->at(m)->method_data();
2450     if (mdo != nullptr) {
2451       mdo->clean_method_data(/*always_clean*/false);
2452     }
2453   }
2454 }
2455 
2456 void InstanceKlass::metaspace_pointers_do(MetaspaceClosure* it) {
2457   Klass::metaspace_pointers_do(it);
2458 
2459   if (log_is_enabled(Trace, cds)) {
2460     ResourceMark rm;
2461     log_trace(cds)("Iter(InstanceKlass): %p (%s)", this, external_name());
2462   }
2463 
2464   it->push(&_annotations);
2465   it->push((Klass**)&_array_klasses);
2466   if (!is_rewritten()) {
2467     it->push(&_constants, MetaspaceClosure::_writable);
2468   } else {
2469     it->push(&_constants);
2470   }
2471   it->push(&_inner_classes);
2472 #if INCLUDE_JVMTI
2473   it->push(&_previous_versions);
2474 #endif
2475 #if INCLUDE_CDS
2476   // For "old" classes with methods containing the jsr bytecode, the _methods array will
2477   // be rewritten during runtime (see Rewriter::rewrite_jsrs()). So setting the _methods to
2478   // be writable. The length check on the _methods is necessary because classes which
2479   // don't have any methods share the Universe::_the_empty_method_array which is in the RO region.
2480   if (_methods != nullptr && _methods->length() > 0 &&
2481       !can_be_verified_at_dumptime() && methods_contain_jsr_bytecode()) {
2482     // To handle jsr bytecode, new Method* maybe stored into _methods
2483     it->push(&_methods, MetaspaceClosure::_writable);
2484   } else {
2485 #endif
2486     it->push(&_methods);
2487 #if INCLUDE_CDS
2488   }
2489 #endif
2490   it->push(&_default_methods);
2491   it->push(&_local_interfaces);
2492   it->push(&_transitive_interfaces);
2493   it->push(&_method_ordering);
2494   if (!is_rewritten()) {
2495     it->push(&_default_vtable_indices, MetaspaceClosure::_writable);
2496   } else {
2497     it->push(&_default_vtable_indices);
2498   }
2499 
2500   it->push(&_fieldinfo_stream);
2501   // _fields_status might be written into by Rewriter::scan_method() -> fd.set_has_initialized_final_update()
2502   it->push(&_fields_status, MetaspaceClosure::_writable);
2503 
2504   if (itable_length() > 0) {
2505     itableOffsetEntry* ioe = (itableOffsetEntry*)start_of_itable();
2506     int method_table_offset_in_words = ioe->offset()/wordSize;
2507     int itable_offset_in_words = (int)(start_of_itable() - (intptr_t*)this);
2508 
2509     int nof_interfaces = (method_table_offset_in_words - itable_offset_in_words)
2510                          / itableOffsetEntry::size();
2511 
2512     for (int i = 0; i < nof_interfaces; i ++, ioe ++) {
2513       if (ioe->interface_klass() != nullptr) {
2514         it->push(ioe->interface_klass_addr());
2515         itableMethodEntry* ime = ioe->first_method_entry(this);
2516         int n = klassItable::method_count_for_interface(ioe->interface_klass());
2517         for (int index = 0; index < n; index ++) {
2518           it->push(ime[index].method_addr());
2519         }
2520       }
2521     }
2522   }
2523 
2524   it->push(&_nest_members);
2525   it->push(&_permitted_subclasses);
2526   it->push(&_record_components);
2527 }
2528 
2529 #if INCLUDE_CDS
2530 void InstanceKlass::remove_unshareable_info() {
2531 
2532   if (is_linked()) {
2533     assert(can_be_verified_at_dumptime(), "must be");
2534     // Remember this so we can avoid walking the hierarchy at runtime.
2535     set_verified_at_dump_time();
2536   }
2537 
2538   Klass::remove_unshareable_info();
2539 
2540   if (SystemDictionaryShared::has_class_failed_verification(this)) {
2541     // Classes are attempted to link during dumping and may fail,
2542     // but these classes are still in the dictionary and class list in CLD.
2543     // If the class has failed verification, there is nothing else to remove.
2544     return;
2545   }
2546 
2547   // Reset to the 'allocated' state to prevent any premature accessing to
2548   // a shared class at runtime while the class is still being loaded and
2549   // restored. A class' init_state is set to 'loaded' at runtime when it's
2550   // being added to class hierarchy (see InstanceKlass:::add_to_hierarchy()).
2551   _init_state = allocated;
2552 
2553   { // Otherwise this needs to take out the Compile_lock.
2554     assert(SafepointSynchronize::is_at_safepoint(), "only called at safepoint");
2555     init_implementor();
2556   }
2557 
2558   constants()->remove_unshareable_info();
2559 
2560   for (int i = 0; i < methods()->length(); i++) {
2561     Method* m = methods()->at(i);
2562     m->remove_unshareable_info();
2563   }
2564 
2565   // do array classes also.
2566   if (array_klasses() != nullptr) {
2567     array_klasses()->remove_unshareable_info();
2568   }
2569 
2570   // These are not allocated from metaspace. They are safe to set to null.
2571   _source_debug_extension = nullptr;
2572   _dep_context = nullptr;
2573   _osr_nmethods_head = nullptr;
2574 #if INCLUDE_JVMTI
2575   _breakpoints = nullptr;
2576   _previous_versions = nullptr;
2577   _cached_class_file = nullptr;
2578   _jvmti_cached_class_field_map = nullptr;
2579 #endif
2580 
2581   _init_thread = nullptr;
2582   _methods_jmethod_ids = nullptr;
2583   _jni_ids = nullptr;
2584   _oop_map_cache = nullptr;
2585   // clear _nest_host to ensure re-load at runtime
2586   _nest_host = nullptr;
2587   init_shared_package_entry();
2588   _dep_context_last_cleaned = 0;
2589   _init_monitor = nullptr;
2590 
2591   remove_unshareable_flags();
2592 }
2593 
2594 void InstanceKlass::remove_unshareable_flags() {
2595   // clear all the flags/stats that shouldn't be in the archived version
2596   assert(!is_scratch_class(), "must be");
2597   assert(!has_been_redefined(), "must be");
2598 #if INCLUDE_JVMTI
2599   set_is_being_redefined(false);
2600 #endif
2601   set_has_resolved_methods(false);
2602 }
2603 
2604 void InstanceKlass::remove_java_mirror() {
2605   Klass::remove_java_mirror();
2606 
2607   // do array classes also.
2608   if (array_klasses() != nullptr) {
2609     array_klasses()->remove_java_mirror();
2610   }
2611 }
2612 
2613 void InstanceKlass::init_shared_package_entry() {
2614   assert(CDSConfig::is_dumping_archive(), "must be");
2615 #if !INCLUDE_CDS_JAVA_HEAP
2616   _package_entry = nullptr;
2617 #else
2618   if (CDSConfig::is_dumping_full_module_graph()) {
2619     if (is_shared_unregistered_class()) {
2620       _package_entry = nullptr;
2621     } else {
2622       _package_entry = PackageEntry::get_archived_entry(_package_entry);
2623     }
2624   } else if (CDSConfig::is_dumping_dynamic_archive() &&
2625              CDSConfig::is_using_full_module_graph() &&
2626              MetaspaceShared::is_in_shared_metaspace(_package_entry)) {
2627     // _package_entry is an archived package in the base archive. Leave it as is.
2628   } else {
2629     _package_entry = nullptr;
2630   }
2631   ArchivePtrMarker::mark_pointer((address**)&_package_entry);
2632 #endif
2633 }
2634 
2635 void InstanceKlass::compute_has_loops_flag_for_methods() {
2636   Array<Method*>* methods = this->methods();
2637   for (int index = 0; index < methods->length(); ++index) {
2638     Method* m = methods->at(index);
2639     if (!m->is_overpass()) { // work around JDK-8305771
2640       m->compute_has_loops_flag();
2641     }
2642   }
2643 }
2644 
2645 void InstanceKlass::restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain,
2646                                              PackageEntry* pkg_entry, TRAPS) {
2647   // InstanceKlass::add_to_hierarchy() sets the init_state to loaded
2648   // before the InstanceKlass is added to the SystemDictionary. Make
2649   // sure the current state is <loaded.
2650   assert(!is_loaded(), "invalid init state");
2651   assert(!shared_loading_failed(), "Must not try to load failed class again");
2652   set_package(loader_data, pkg_entry, CHECK);
2653   Klass::restore_unshareable_info(loader_data, protection_domain, CHECK);
2654 
2655   Array<Method*>* methods = this->methods();
2656   int num_methods = methods->length();
2657   for (int index = 0; index < num_methods; ++index) {
2658     methods->at(index)->restore_unshareable_info(CHECK);
2659   }
2660 #if INCLUDE_JVMTI
2661   if (JvmtiExport::has_redefined_a_class()) {
2662     // Reinitialize vtable because RedefineClasses may have changed some
2663     // entries in this vtable for super classes so the CDS vtable might
2664     // point to old or obsolete entries.  RedefineClasses doesn't fix up
2665     // vtables in the shared system dictionary, only the main one.
2666     // It also redefines the itable too so fix that too.
2667     // First fix any default methods that point to a super class that may
2668     // have been redefined.
2669     bool trace_name_printed = false;
2670     adjust_default_methods(&trace_name_printed);
2671     vtable().initialize_vtable();
2672     itable().initialize_itable();
2673   }
2674 #endif
2675 
2676   // restore constant pool resolved references
2677   constants()->restore_unshareable_info(CHECK);
2678 
2679   if (array_klasses() != nullptr) {
2680     // To get a consistent list of classes we need MultiArray_lock to ensure
2681     // array classes aren't observed while they are being restored.
2682     RecursiveLocker rl(MultiArray_lock, THREAD);
2683     assert(this == array_klasses()->bottom_klass(), "sanity");
2684     // Array classes have null protection domain.
2685     // --> see ArrayKlass::complete_create_array_klass()
2686     array_klasses()->restore_unshareable_info(class_loader_data(), Handle(), CHECK);
2687   }
2688 
2689   // Initialize @ValueBased class annotation
2690   if (DiagnoseSyncOnValueBasedClasses && has_value_based_class_annotation()) {
2691     set_is_value_based();
2692   }
2693 
2694   // restore the monitor
2695   _init_monitor = create_init_monitor("InstanceKlassInitMonitorRestored_lock");
2696 }
2697 
2698 // Check if a class or any of its supertypes has a version older than 50.
2699 // CDS will not perform verification of old classes during dump time because
2700 // without changing the old verifier, the verification constraint cannot be
2701 // retrieved during dump time.
2702 // Verification of archived old classes will be performed during run time.
2703 bool InstanceKlass::can_be_verified_at_dumptime() const {
2704   if (MetaspaceShared::is_in_shared_metaspace(this)) {
2705     // This is a class that was dumped into the base archive, so we know
2706     // it was verified at dump time.
2707     return true;
2708   }
2709   if (major_version() < 50 /*JAVA_6_VERSION*/) {
2710     return false;
2711   }
2712   if (java_super() != nullptr && !java_super()->can_be_verified_at_dumptime()) {
2713     return false;
2714   }
2715   Array<InstanceKlass*>* interfaces = local_interfaces();
2716   int len = interfaces->length();
2717   for (int i = 0; i < len; i++) {
2718     if (!interfaces->at(i)->can_be_verified_at_dumptime()) {
2719       return false;
2720     }
2721   }
2722   return true;
2723 }
2724 
2725 bool InstanceKlass::methods_contain_jsr_bytecode() const {
2726   Thread* thread = Thread::current();
2727   for (int i = 0; i < _methods->length(); i++) {
2728     methodHandle m(thread, _methods->at(i));
2729     BytecodeStream bcs(m);
2730     while (!bcs.is_last_bytecode()) {
2731       Bytecodes::Code opcode = bcs.next();
2732       if (opcode == Bytecodes::_jsr || opcode == Bytecodes::_jsr_w) {
2733         return true;
2734       }
2735     }
2736   }
2737   return false;
2738 }
2739 #endif // INCLUDE_CDS
2740 
2741 #if INCLUDE_JVMTI
2742 static void clear_all_breakpoints(Method* m) {
2743   m->clear_all_breakpoints();
2744 }
2745 #endif
2746 
2747 void InstanceKlass::unload_class(InstanceKlass* ik) {
2748   // Release dependencies.
2749   ik->dependencies().remove_all_dependents();
2750 
2751   // notify the debugger
2752   if (JvmtiExport::should_post_class_unload()) {
2753     JvmtiExport::post_class_unload(ik);
2754   }
2755 
2756   // notify ClassLoadingService of class unload
2757   ClassLoadingService::notify_class_unloaded(ik);
2758 
2759   SystemDictionaryShared::handle_class_unloading(ik);
2760 
2761   if (log_is_enabled(Info, class, unload)) {
2762     ResourceMark rm;
2763     log_info(class, unload)("unloading class %s " PTR_FORMAT, ik->external_name(), p2i(ik));
2764   }
2765 
2766   Events::log_class_unloading(Thread::current(), ik);
2767 
2768 #if INCLUDE_JFR
2769   assert(ik != nullptr, "invariant");
2770   EventClassUnload event;
2771   event.set_unloadedClass(ik);
2772   event.set_definingClassLoader(ik->class_loader_data());
2773   event.commit();
2774 #endif
2775 }
2776 
2777 static void method_release_C_heap_structures(Method* m) {
2778   m->release_C_heap_structures();
2779 }
2780 
2781 // Called also by InstanceKlass::deallocate_contents, with false for release_sub_metadata.
2782 void InstanceKlass::release_C_heap_structures(bool release_sub_metadata) {
2783   // Clean up C heap
2784   Klass::release_C_heap_structures();
2785 
2786   // Deallocate and call destructors for MDO mutexes
2787   if (release_sub_metadata) {
2788     methods_do(method_release_C_heap_structures);
2789   }
2790 
2791   // Destroy the init_monitor
2792   delete _init_monitor;
2793 
2794   // Deallocate oop map cache
2795   if (_oop_map_cache != nullptr) {
2796     delete _oop_map_cache;
2797     _oop_map_cache = nullptr;
2798   }
2799 
2800   // Deallocate JNI identifiers for jfieldIDs
2801   JNIid::deallocate(jni_ids());
2802   set_jni_ids(nullptr);
2803 
2804   jmethodID* jmeths = methods_jmethod_ids_acquire();
2805   if (jmeths != nullptr) {
2806     release_set_methods_jmethod_ids(nullptr);
2807     FreeHeap(jmeths);
2808   }
2809 
2810   assert(_dep_context == nullptr,
2811          "dependencies should already be cleaned");
2812 
2813 #if INCLUDE_JVMTI
2814   // Deallocate breakpoint records
2815   if (breakpoints() != 0x0) {
2816     methods_do(clear_all_breakpoints);
2817     assert(breakpoints() == 0x0, "should have cleared breakpoints");
2818   }
2819 
2820   // deallocate the cached class file
2821   if (_cached_class_file != nullptr) {
2822     os::free(_cached_class_file);
2823     _cached_class_file = nullptr;
2824   }
2825 #endif
2826 
2827   FREE_C_HEAP_ARRAY(char, _source_debug_extension);
2828 
2829   if (release_sub_metadata) {
2830     constants()->release_C_heap_structures();
2831   }
2832 }
2833 
2834 // The constant pool is on stack if any of the methods are executing or
2835 // referenced by handles.
2836 bool InstanceKlass::on_stack() const {
2837   return _constants->on_stack();
2838 }
2839 
2840 Symbol* InstanceKlass::source_file_name() const               { return _constants->source_file_name(); }
2841 u2 InstanceKlass::source_file_name_index() const              { return _constants->source_file_name_index(); }
2842 void InstanceKlass::set_source_file_name_index(u2 sourcefile_index) { _constants->set_source_file_name_index(sourcefile_index); }
2843 
2844 // minor and major version numbers of class file
2845 u2 InstanceKlass::minor_version() const                 { return _constants->minor_version(); }
2846 void InstanceKlass::set_minor_version(u2 minor_version) { _constants->set_minor_version(minor_version); }
2847 u2 InstanceKlass::major_version() const                 { return _constants->major_version(); }
2848 void InstanceKlass::set_major_version(u2 major_version) { _constants->set_major_version(major_version); }
2849 
2850 InstanceKlass* InstanceKlass::get_klass_version(int version) {
2851   for (InstanceKlass* ik = this; ik != nullptr; ik = ik->previous_versions()) {
2852     if (ik->constants()->version() == version) {
2853       return ik;
2854     }
2855   }
2856   return nullptr;
2857 }
2858 
2859 void InstanceKlass::set_source_debug_extension(const char* array, int length) {
2860   if (array == nullptr) {
2861     _source_debug_extension = nullptr;
2862   } else {
2863     // Adding one to the attribute length in order to store a null terminator
2864     // character could cause an overflow because the attribute length is
2865     // already coded with an u4 in the classfile, but in practice, it's
2866     // unlikely to happen.
2867     assert((length+1) > length, "Overflow checking");
2868     char* sde = NEW_C_HEAP_ARRAY(char, (length + 1), mtClass);
2869     for (int i = 0; i < length; i++) {
2870       sde[i] = array[i];
2871     }
2872     sde[length] = '\0';
2873     _source_debug_extension = sde;
2874   }
2875 }
2876 
2877 Symbol* InstanceKlass::generic_signature() const                   { return _constants->generic_signature(); }
2878 u2 InstanceKlass::generic_signature_index() const                  { return _constants->generic_signature_index(); }
2879 void InstanceKlass::set_generic_signature_index(u2 sig_index)      { _constants->set_generic_signature_index(sig_index); }
2880 
2881 const char* InstanceKlass::signature_name() const {
2882 
2883   // Get the internal name as a c string
2884   const char* src = (const char*) (name()->as_C_string());
2885   const int src_length = (int)strlen(src);
2886 
2887   char* dest = NEW_RESOURCE_ARRAY(char, src_length + 3);
2888 
2889   // Add L as type indicator
2890   int dest_index = 0;
2891   dest[dest_index++] = JVM_SIGNATURE_CLASS;
2892 
2893   // Add the actual class name
2894   for (int src_index = 0; src_index < src_length; ) {
2895     dest[dest_index++] = src[src_index++];
2896   }
2897 
2898   if (is_hidden()) { // Replace the last '+' with a '.'.
2899     for (int index = (int)src_length; index > 0; index--) {
2900       if (dest[index] == '+') {
2901         dest[index] = JVM_SIGNATURE_DOT;
2902         break;
2903       }
2904     }
2905   }
2906 
2907   // Add the semicolon and the null
2908   dest[dest_index++] = JVM_SIGNATURE_ENDCLASS;
2909   dest[dest_index] = '\0';
2910   return dest;
2911 }
2912 
2913 ModuleEntry* InstanceKlass::module() const {
2914   if (is_hidden() &&
2915       in_unnamed_package() &&
2916       class_loader_data()->has_class_mirror_holder()) {
2917     // For a non-strong hidden class defined to an unnamed package,
2918     // its (class held) CLD will not have an unnamed module created for it.
2919     // Two choices to find the correct ModuleEntry:
2920     // 1. If hidden class is within a nest, use nest host's module
2921     // 2. Find the unnamed module off from the class loader
2922     // For now option #2 is used since a nest host is not set until
2923     // after the instance class is created in jvm_lookup_define_class().
2924     if (class_loader_data()->is_boot_class_loader_data()) {
2925       return ClassLoaderData::the_null_class_loader_data()->unnamed_module();
2926     } else {
2927       oop module = java_lang_ClassLoader::unnamedModule(class_loader_data()->class_loader());
2928       assert(java_lang_Module::is_instance(module), "Not an instance of java.lang.Module");
2929       return java_lang_Module::module_entry(module);
2930     }
2931   }
2932 
2933   // Class is in a named package
2934   if (!in_unnamed_package()) {
2935     return _package_entry->module();
2936   }
2937 
2938   // Class is in an unnamed package, return its loader's unnamed module
2939   return class_loader_data()->unnamed_module();
2940 }
2941 
2942 void InstanceKlass::set_package(ClassLoaderData* loader_data, PackageEntry* pkg_entry, TRAPS) {
2943 
2944   // ensure java/ packages only loaded by boot or platform builtin loaders
2945   // not needed for shared class since CDS does not archive prohibited classes.
2946   if (!is_shared()) {
2947     check_prohibited_package(name(), loader_data, CHECK);
2948   }
2949 
2950   if (is_shared() && _package_entry != nullptr) {
2951     if (CDSConfig::is_using_full_module_graph() && _package_entry == pkg_entry) {
2952       // we can use the saved package
2953       assert(MetaspaceShared::is_in_shared_metaspace(_package_entry), "must be");
2954       return;
2955     } else {
2956       _package_entry = nullptr;
2957     }
2958   }
2959 
2960   // ClassLoader::package_from_class_name has already incremented the refcount of the symbol
2961   // it returns, so we need to decrement it when the current function exits.
2962   TempNewSymbol from_class_name =
2963       (pkg_entry != nullptr) ? nullptr : ClassLoader::package_from_class_name(name());
2964 
2965   Symbol* pkg_name;
2966   if (pkg_entry != nullptr) {
2967     pkg_name = pkg_entry->name();
2968   } else {
2969     pkg_name = from_class_name;
2970   }
2971 
2972   if (pkg_name != nullptr && loader_data != nullptr) {
2973 
2974     // Find in class loader's package entry table.
2975     _package_entry = pkg_entry != nullptr ? pkg_entry : loader_data->packages()->lookup_only(pkg_name);
2976 
2977     // If the package name is not found in the loader's package
2978     // entry table, it is an indication that the package has not
2979     // been defined. Consider it defined within the unnamed module.
2980     if (_package_entry == nullptr) {
2981 
2982       if (!ModuleEntryTable::javabase_defined()) {
2983         // Before java.base is defined during bootstrapping, define all packages in
2984         // the java.base module.  If a non-java.base package is erroneously placed
2985         // in the java.base module it will be caught later when java.base
2986         // is defined by ModuleEntryTable::verify_javabase_packages check.
2987         assert(ModuleEntryTable::javabase_moduleEntry() != nullptr, JAVA_BASE_NAME " module is null");
2988         _package_entry = loader_data->packages()->create_entry_if_absent(pkg_name, ModuleEntryTable::javabase_moduleEntry());
2989       } else {
2990         assert(loader_data->unnamed_module() != nullptr, "unnamed module is null");
2991         _package_entry = loader_data->packages()->create_entry_if_absent(pkg_name, loader_data->unnamed_module());
2992       }
2993 
2994       // A package should have been successfully created
2995       DEBUG_ONLY(ResourceMark rm(THREAD));
2996       assert(_package_entry != nullptr, "Package entry for class %s not found, loader %s",
2997              name()->as_C_string(), loader_data->loader_name_and_id());
2998     }
2999 
3000     if (log_is_enabled(Debug, module)) {
3001       ResourceMark rm(THREAD);
3002       ModuleEntry* m = _package_entry->module();
3003       log_trace(module)("Setting package: class: %s, package: %s, loader: %s, module: %s",
3004                         external_name(),
3005                         pkg_name->as_C_string(),
3006                         loader_data->loader_name_and_id(),
3007                         (m->is_named() ? m->name()->as_C_string() : UNNAMED_MODULE));
3008     }
3009   } else {
3010     ResourceMark rm(THREAD);
3011     log_trace(module)("Setting package: class: %s, package: unnamed, loader: %s, module: %s",
3012                       external_name(),
3013                       (loader_data != nullptr) ? loader_data->loader_name_and_id() : "null",
3014                       UNNAMED_MODULE);
3015   }
3016 }
3017 
3018 // Function set_classpath_index ensures that for a non-null _package_entry
3019 // of the InstanceKlass, the entry is in the boot loader's package entry table.
3020 // It then sets the classpath_index in the package entry record.
3021 //
3022 // The classpath_index field is used to find the entry on the boot loader class
3023 // path for packages with classes loaded by the boot loader from -Xbootclasspath/a
3024 // in an unnamed module.  It is also used to indicate (for all packages whose
3025 // classes are loaded by the boot loader) that at least one of the package's
3026 // classes has been loaded.
3027 void InstanceKlass::set_classpath_index(s2 path_index) {
3028   if (_package_entry != nullptr) {
3029     DEBUG_ONLY(PackageEntryTable* pkg_entry_tbl = ClassLoaderData::the_null_class_loader_data()->packages();)
3030     assert(pkg_entry_tbl->lookup_only(_package_entry->name()) == _package_entry, "Should be same");
3031     assert(path_index != -1, "Unexpected classpath_index");
3032     _package_entry->set_classpath_index(path_index);
3033   }
3034 }
3035 
3036 // different versions of is_same_class_package
3037 
3038 bool InstanceKlass::is_same_class_package(const Klass* class2) const {
3039   oop classloader1 = this->class_loader();
3040   PackageEntry* classpkg1 = this->package();
3041   if (class2->is_objArray_klass()) {
3042     class2 = ObjArrayKlass::cast(class2)->bottom_klass();
3043   }
3044 
3045   oop classloader2;
3046   PackageEntry* classpkg2;
3047   if (class2->is_instance_klass()) {
3048     classloader2 = class2->class_loader();
3049     classpkg2 = class2->package();
3050   } else {
3051     assert(class2->is_typeArray_klass(), "should be type array");
3052     classloader2 = nullptr;
3053     classpkg2 = nullptr;
3054   }
3055 
3056   // Same package is determined by comparing class loader
3057   // and package entries. Both must be the same. This rule
3058   // applies even to classes that are defined in the unnamed
3059   // package, they still must have the same class loader.
3060   if ((classloader1 == classloader2) && (classpkg1 == classpkg2)) {
3061     return true;
3062   }
3063 
3064   return false;
3065 }
3066 
3067 // return true if this class and other_class are in the same package. Classloader
3068 // and classname information is enough to determine a class's package
3069 bool InstanceKlass::is_same_class_package(oop other_class_loader,
3070                                           const Symbol* other_class_name) const {
3071   if (class_loader() != other_class_loader) {
3072     return false;
3073   }
3074   if (name()->fast_compare(other_class_name) == 0) {
3075      return true;
3076   }
3077 
3078   {
3079     ResourceMark rm;
3080 
3081     bool bad_class_name = false;
3082     TempNewSymbol other_pkg = ClassLoader::package_from_class_name(other_class_name, &bad_class_name);
3083     if (bad_class_name) {
3084       return false;
3085     }
3086     // Check that package_from_class_name() returns null, not "", if there is no package.
3087     assert(other_pkg == nullptr || other_pkg->utf8_length() > 0, "package name is empty string");
3088 
3089     const Symbol* const this_package_name =
3090       this->package() != nullptr ? this->package()->name() : nullptr;
3091 
3092     if (this_package_name == nullptr || other_pkg == nullptr) {
3093       // One of the two doesn't have a package.  Only return true if the other
3094       // one also doesn't have a package.
3095       return this_package_name == other_pkg;
3096     }
3097 
3098     // Check if package is identical
3099     return this_package_name->fast_compare(other_pkg) == 0;
3100   }
3101 }
3102 
3103 static bool is_prohibited_package_slow(Symbol* class_name) {
3104   // Caller has ResourceMark
3105   int length;
3106   jchar* unicode = class_name->as_unicode(length);
3107   return (length >= 5 &&
3108           unicode[0] == 'j' &&
3109           unicode[1] == 'a' &&
3110           unicode[2] == 'v' &&
3111           unicode[3] == 'a' &&
3112           unicode[4] == '/');
3113 }
3114 
3115 // Only boot and platform class loaders can define classes in "java/" packages.
3116 void InstanceKlass::check_prohibited_package(Symbol* class_name,
3117                                              ClassLoaderData* loader_data,
3118                                              TRAPS) {
3119   if (!loader_data->is_boot_class_loader_data() &&
3120       !loader_data->is_platform_class_loader_data() &&
3121       class_name != nullptr && class_name->utf8_length() >= 5) {
3122     ResourceMark rm(THREAD);
3123     bool prohibited;
3124     const u1* base = class_name->base();
3125     if ((base[0] | base[1] | base[2] | base[3] | base[4]) & 0x80) {
3126       prohibited = is_prohibited_package_slow(class_name);
3127     } else {
3128       char* name = class_name->as_C_string();
3129       prohibited = (strncmp(name, JAVAPKG, JAVAPKG_LEN) == 0 && name[JAVAPKG_LEN] == '/');
3130     }
3131     if (prohibited) {
3132       TempNewSymbol pkg_name = ClassLoader::package_from_class_name(class_name);
3133       assert(pkg_name != nullptr, "Error in parsing package name starting with 'java/'");
3134       char* name = pkg_name->as_C_string();
3135       const char* class_loader_name = loader_data->loader_name_and_id();
3136       StringUtils::replace_no_expand(name, "/", ".");
3137       const char* msg_text1 = "Class loader (instance of): ";
3138       const char* msg_text2 = " tried to load prohibited package name: ";
3139       size_t len = strlen(msg_text1) + strlen(class_loader_name) + strlen(msg_text2) + strlen(name) + 1;
3140       char* message = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, len);
3141       jio_snprintf(message, len, "%s%s%s%s", msg_text1, class_loader_name, msg_text2, name);
3142       THROW_MSG(vmSymbols::java_lang_SecurityException(), message);
3143     }
3144   }
3145   return;
3146 }
3147 
3148 bool InstanceKlass::find_inner_classes_attr(int* ooff, int* noff, TRAPS) const {
3149   constantPoolHandle i_cp(THREAD, constants());
3150   for (InnerClassesIterator iter(this); !iter.done(); iter.next()) {
3151     int ioff = iter.inner_class_info_index();
3152     if (ioff != 0) {
3153       // Check to see if the name matches the class we're looking for
3154       // before attempting to find the class.
3155       if (i_cp->klass_name_at_matches(this, ioff)) {
3156         Klass* inner_klass = i_cp->klass_at(ioff, CHECK_false);
3157         if (this == inner_klass) {
3158           *ooff = iter.outer_class_info_index();
3159           *noff = iter.inner_name_index();
3160           return true;
3161         }
3162       }
3163     }
3164   }
3165   return false;
3166 }
3167 
3168 InstanceKlass* InstanceKlass::compute_enclosing_class(bool* inner_is_member, TRAPS) const {
3169   InstanceKlass* outer_klass = nullptr;
3170   *inner_is_member = false;
3171   int ooff = 0, noff = 0;
3172   bool has_inner_classes_attr = find_inner_classes_attr(&ooff, &noff, THREAD);
3173   if (has_inner_classes_attr) {
3174     constantPoolHandle i_cp(THREAD, constants());
3175     if (ooff != 0) {
3176       Klass* ok = i_cp->klass_at(ooff, CHECK_NULL);
3177       if (!ok->is_instance_klass()) {
3178         // If the outer class is not an instance klass then it cannot have
3179         // declared any inner classes.
3180         ResourceMark rm(THREAD);
3181         Exceptions::fthrow(
3182           THREAD_AND_LOCATION,
3183           vmSymbols::java_lang_IncompatibleClassChangeError(),
3184           "%s and %s disagree on InnerClasses attribute",
3185           ok->external_name(),
3186           external_name());
3187         return nullptr;
3188       }
3189       outer_klass = InstanceKlass::cast(ok);
3190       *inner_is_member = true;
3191     }
3192     if (nullptr == outer_klass) {
3193       // It may be a local class; try for that.
3194       int encl_method_class_idx = enclosing_method_class_index();
3195       if (encl_method_class_idx != 0) {
3196         Klass* ok = i_cp->klass_at(encl_method_class_idx, CHECK_NULL);
3197         outer_klass = InstanceKlass::cast(ok);
3198         *inner_is_member = false;
3199       }
3200     }
3201   }
3202 
3203   // If no inner class attribute found for this class.
3204   if (nullptr == outer_klass) return nullptr;
3205 
3206   // Throws an exception if outer klass has not declared k as an inner klass
3207   // We need evidence that each klass knows about the other, or else
3208   // the system could allow a spoof of an inner class to gain access rights.
3209   Reflection::check_for_inner_class(outer_klass, this, *inner_is_member, CHECK_NULL);
3210   return outer_klass;
3211 }
3212 
3213 jint InstanceKlass::compute_modifier_flags() const {
3214   jint access = access_flags().as_int();
3215 
3216   // But check if it happens to be member class.
3217   InnerClassesIterator iter(this);
3218   for (; !iter.done(); iter.next()) {
3219     int ioff = iter.inner_class_info_index();
3220     // Inner class attribute can be zero, skip it.
3221     // Strange but true:  JVM spec. allows null inner class refs.
3222     if (ioff == 0) continue;
3223 
3224     // only look at classes that are already loaded
3225     // since we are looking for the flags for our self.
3226     Symbol* inner_name = constants()->klass_name_at(ioff);
3227     if (name() == inner_name) {
3228       // This is really a member class.
3229       access = iter.inner_access_flags();
3230       break;
3231     }
3232   }
3233   // Remember to strip ACC_SUPER bit
3234   return (access & (~JVM_ACC_SUPER)) & JVM_ACC_WRITTEN_FLAGS;
3235 }
3236 
3237 jint InstanceKlass::jvmti_class_status() const {
3238   jint result = 0;
3239 
3240   if (is_linked()) {
3241     result |= JVMTI_CLASS_STATUS_VERIFIED | JVMTI_CLASS_STATUS_PREPARED;
3242   }
3243 
3244   if (is_initialized()) {
3245     assert(is_linked(), "Class status is not consistent");
3246     result |= JVMTI_CLASS_STATUS_INITIALIZED;
3247   }
3248   if (is_in_error_state()) {
3249     result |= JVMTI_CLASS_STATUS_ERROR;
3250   }
3251   return result;
3252 }
3253 
3254 Method* InstanceKlass::method_at_itable(InstanceKlass* holder, int index, TRAPS) {
3255   bool implements_interface; // initialized by method_at_itable_or_null
3256   Method* m = method_at_itable_or_null(holder, index,
3257                                        implements_interface); // out parameter
3258   if (m != nullptr) {
3259     assert(implements_interface, "sanity");
3260     return m;
3261   } else if (implements_interface) {
3262     // Throw AbstractMethodError since corresponding itable slot is empty.
3263     THROW_NULL(vmSymbols::java_lang_AbstractMethodError());
3264   } else {
3265     // If the interface isn't implemented by the receiver class,
3266     // the VM should throw IncompatibleClassChangeError.
3267     ResourceMark rm(THREAD);
3268     stringStream ss;
3269     bool same_module = (module() == holder->module());
3270     ss.print("Receiver class %s does not implement "
3271              "the interface %s defining the method to be called "
3272              "(%s%s%s)",
3273              external_name(), holder->external_name(),
3274              (same_module) ? joint_in_module_of_loader(holder) : class_in_module_of_loader(),
3275              (same_module) ? "" : "; ",
3276              (same_module) ? "" : holder->class_in_module_of_loader());
3277     THROW_MSG_NULL(vmSymbols::java_lang_IncompatibleClassChangeError(), ss.as_string());
3278   }
3279 }
3280 
3281 Method* InstanceKlass::method_at_itable_or_null(InstanceKlass* holder, int index, bool& implements_interface) {
3282   klassItable itable(this);
3283   for (int i = 0; i < itable.size_offset_table(); i++) {
3284     itableOffsetEntry* offset_entry = itable.offset_entry(i);
3285     if (offset_entry->interface_klass() == holder) {
3286       implements_interface = true;
3287       itableMethodEntry* ime = offset_entry->first_method_entry(this);
3288       Method* m = ime[index].method();
3289       return m;
3290     }
3291   }
3292   implements_interface = false;
3293   return nullptr; // offset entry not found
3294 }
3295 
3296 int InstanceKlass::vtable_index_of_interface_method(Method* intf_method) {
3297   assert(is_linked(), "required");
3298   assert(intf_method->method_holder()->is_interface(), "not an interface method");
3299   assert(is_subtype_of(intf_method->method_holder()), "interface not implemented");
3300 
3301   int vtable_index = Method::invalid_vtable_index;
3302   Symbol* name = intf_method->name();
3303   Symbol* signature = intf_method->signature();
3304 
3305   // First check in default method array
3306   if (!intf_method->is_abstract() && default_methods() != nullptr) {
3307     int index = find_method_index(default_methods(),
3308                                   name, signature,
3309                                   Klass::OverpassLookupMode::find,
3310                                   Klass::StaticLookupMode::find,
3311                                   Klass::PrivateLookupMode::find);
3312     if (index >= 0) {
3313       vtable_index = default_vtable_indices()->at(index);
3314     }
3315   }
3316   if (vtable_index == Method::invalid_vtable_index) {
3317     // get vtable_index for miranda methods
3318     klassVtable vt = vtable();
3319     vtable_index = vt.index_of_miranda(name, signature);
3320   }
3321   return vtable_index;
3322 }
3323 
3324 #if INCLUDE_JVMTI
3325 // update default_methods for redefineclasses for methods that are
3326 // not yet in the vtable due to concurrent subclass define and superinterface
3327 // redefinition
3328 // Note: those in the vtable, should have been updated via adjust_method_entries
3329 void InstanceKlass::adjust_default_methods(bool* trace_name_printed) {
3330   // search the default_methods for uses of either obsolete or EMCP methods
3331   if (default_methods() != nullptr) {
3332     for (int index = 0; index < default_methods()->length(); index ++) {
3333       Method* old_method = default_methods()->at(index);
3334       if (old_method == nullptr || !old_method->is_old()) {
3335         continue; // skip uninteresting entries
3336       }
3337       assert(!old_method->is_deleted(), "default methods may not be deleted");
3338       Method* new_method = old_method->get_new_method();
3339       default_methods()->at_put(index, new_method);
3340 
3341       if (log_is_enabled(Info, redefine, class, update)) {
3342         ResourceMark rm;
3343         if (!(*trace_name_printed)) {
3344           log_info(redefine, class, update)
3345             ("adjust: klassname=%s default methods from name=%s",
3346              external_name(), old_method->method_holder()->external_name());
3347           *trace_name_printed = true;
3348         }
3349         log_debug(redefine, class, update, vtables)
3350           ("default method update: %s(%s) ",
3351            new_method->name()->as_C_string(), new_method->signature()->as_C_string());
3352       }
3353     }
3354   }
3355 }
3356 #endif // INCLUDE_JVMTI
3357 
3358 // On-stack replacement stuff
3359 void InstanceKlass::add_osr_nmethod(nmethod* n) {
3360   assert_lock_strong(NMethodState_lock);
3361 #ifndef PRODUCT
3362   nmethod* prev = lookup_osr_nmethod(n->method(), n->osr_entry_bci(), n->comp_level(), true);
3363   assert(prev == nullptr || !prev->is_in_use() COMPILER2_PRESENT(|| StressRecompilation),
3364       "redundant OSR recompilation detected. memory leak in CodeCache!");
3365 #endif
3366   // only one compilation can be active
3367   assert(n->is_osr_method(), "wrong kind of nmethod");
3368   n->set_osr_link(osr_nmethods_head());
3369   set_osr_nmethods_head(n);
3370   // Raise the highest osr level if necessary
3371   n->method()->set_highest_osr_comp_level(MAX2(n->method()->highest_osr_comp_level(), n->comp_level()));
3372 
3373   // Get rid of the osr methods for the same bci that have lower levels.
3374   for (int l = CompLevel_limited_profile; l < n->comp_level(); l++) {
3375     nmethod *inv = lookup_osr_nmethod(n->method(), n->osr_entry_bci(), l, true);
3376     if (inv != nullptr && inv->is_in_use()) {
3377       inv->make_not_entrant();
3378     }
3379   }
3380 }
3381 
3382 // Remove osr nmethod from the list. Return true if found and removed.
3383 bool InstanceKlass::remove_osr_nmethod(nmethod* n) {
3384   // This is a short non-blocking critical region, so the no safepoint check is ok.
3385   ConditionalMutexLocker ml(NMethodState_lock, !NMethodState_lock->owned_by_self(), Mutex::_no_safepoint_check_flag);
3386   assert(n->is_osr_method(), "wrong kind of nmethod");
3387   nmethod* last = nullptr;
3388   nmethod* cur  = osr_nmethods_head();
3389   int max_level = CompLevel_none;  // Find the max comp level excluding n
3390   Method* m = n->method();
3391   // Search for match
3392   bool found = false;
3393   while(cur != nullptr && cur != n) {
3394     if (m == cur->method()) {
3395       // Find max level before n
3396       max_level = MAX2(max_level, cur->comp_level());
3397     }
3398     last = cur;
3399     cur = cur->osr_link();
3400   }
3401   nmethod* next = nullptr;
3402   if (cur == n) {
3403     found = true;
3404     next = cur->osr_link();
3405     if (last == nullptr) {
3406       // Remove first element
3407       set_osr_nmethods_head(next);
3408     } else {
3409       last->set_osr_link(next);
3410     }
3411   }
3412   n->set_osr_link(nullptr);
3413   cur = next;
3414   while (cur != nullptr) {
3415     // Find max level after n
3416     if (m == cur->method()) {
3417       max_level = MAX2(max_level, cur->comp_level());
3418     }
3419     cur = cur->osr_link();
3420   }
3421   m->set_highest_osr_comp_level(max_level);
3422   return found;
3423 }
3424 
3425 int InstanceKlass::mark_osr_nmethods(DeoptimizationScope* deopt_scope, const Method* m) {
3426   ConditionalMutexLocker ml(NMethodState_lock, !NMethodState_lock->owned_by_self(), Mutex::_no_safepoint_check_flag);
3427   nmethod* osr = osr_nmethods_head();
3428   int found = 0;
3429   while (osr != nullptr) {
3430     assert(osr->is_osr_method(), "wrong kind of nmethod found in chain");
3431     if (osr->method() == m) {
3432       deopt_scope->mark(osr);
3433       found++;
3434     }
3435     osr = osr->osr_link();
3436   }
3437   return found;
3438 }
3439 
3440 nmethod* InstanceKlass::lookup_osr_nmethod(const Method* m, int bci, int comp_level, bool match_level) const {
3441   ConditionalMutexLocker ml(NMethodState_lock, !NMethodState_lock->owned_by_self(), Mutex::_no_safepoint_check_flag);
3442   nmethod* osr = osr_nmethods_head();
3443   nmethod* best = nullptr;
3444   while (osr != nullptr) {
3445     assert(osr->is_osr_method(), "wrong kind of nmethod found in chain");
3446     // There can be a time when a c1 osr method exists but we are waiting
3447     // for a c2 version. When c2 completes its osr nmethod we will trash
3448     // the c1 version and only be able to find the c2 version. However
3449     // while we overflow in the c1 code at back branches we don't want to
3450     // try and switch to the same code as we are already running
3451 
3452     if (osr->method() == m &&
3453         (bci == InvocationEntryBci || osr->osr_entry_bci() == bci)) {
3454       if (match_level) {
3455         if (osr->comp_level() == comp_level) {
3456           // Found a match - return it.
3457           return osr;
3458         }
3459       } else {
3460         if (best == nullptr || (osr->comp_level() > best->comp_level())) {
3461           if (osr->comp_level() == CompilationPolicy::highest_compile_level()) {
3462             // Found the best possible - return it.
3463             return osr;
3464           }
3465           best = osr;
3466         }
3467       }
3468     }
3469     osr = osr->osr_link();
3470   }
3471 
3472   assert(match_level == false || best == nullptr, "shouldn't pick up anything if match_level is set");
3473   if (best != nullptr && best->comp_level() >= comp_level) {
3474     return best;
3475   }
3476   return nullptr;
3477 }
3478 
3479 // -----------------------------------------------------------------------------------------------------
3480 // Printing
3481 
3482 #define BULLET  " - "
3483 
3484 static const char* state_names[] = {
3485   "allocated", "loaded", "being_linked", "linked", "being_initialized", "fully_initialized", "initialization_error"
3486 };
3487 
3488 static void print_vtable(intptr_t* start, int len, outputStream* st) {
3489   for (int i = 0; i < len; i++) {
3490     intptr_t e = start[i];
3491     st->print("%d : " INTPTR_FORMAT, i, e);
3492     if (MetaspaceObj::is_valid((Metadata*)e)) {
3493       st->print(" ");
3494       ((Metadata*)e)->print_value_on(st);
3495     }
3496     st->cr();
3497   }
3498 }
3499 
3500 static void print_vtable(vtableEntry* start, int len, outputStream* st) {
3501   return print_vtable(reinterpret_cast<intptr_t*>(start), len, st);
3502 }
3503 
3504 const char* InstanceKlass::init_state_name() const {
3505   return state_names[init_state()];
3506 }
3507 
3508 void InstanceKlass::print_on(outputStream* st) const {
3509   assert(is_klass(), "must be klass");
3510   Klass::print_on(st);
3511 
3512   st->print(BULLET"instance size:     %d", size_helper());                        st->cr();
3513   st->print(BULLET"klass size:        %d", size());                               st->cr();
3514   st->print(BULLET"access:            "); access_flags().print_on(st);            st->cr();
3515   st->print(BULLET"flags:             "); _misc_flags.print_on(st);               st->cr();
3516   st->print(BULLET"state:             "); st->print_cr("%s", init_state_name());
3517   st->print(BULLET"name:              "); name()->print_value_on(st);             st->cr();
3518   st->print(BULLET"super:             "); Metadata::print_value_on_maybe_null(st, super()); st->cr();
3519   st->print(BULLET"sub:               ");
3520   Klass* sub = subklass();
3521   int n;
3522   for (n = 0; sub != nullptr; n++, sub = sub->next_sibling()) {
3523     if (n < MaxSubklassPrintSize) {
3524       sub->print_value_on(st);
3525       st->print("   ");
3526     }
3527   }
3528   if (n >= MaxSubklassPrintSize) st->print("(" INTX_FORMAT " more klasses...)", n - MaxSubklassPrintSize);
3529   st->cr();
3530 
3531   if (is_interface()) {
3532     st->print_cr(BULLET"nof implementors:  %d", nof_implementors());
3533     if (nof_implementors() == 1) {
3534       st->print_cr(BULLET"implementor:    ");
3535       st->print("   ");
3536       implementor()->print_value_on(st);
3537       st->cr();
3538     }
3539   }
3540 
3541   st->print(BULLET"arrays:            "); Metadata::print_value_on_maybe_null(st, array_klasses()); st->cr();
3542   st->print(BULLET"methods:           "); methods()->print_value_on(st);               st->cr();
3543   if (Verbose || WizardMode) {
3544     Array<Method*>* method_array = methods();
3545     for (int i = 0; i < method_array->length(); i++) {
3546       st->print("%d : ", i); method_array->at(i)->print_value(); st->cr();
3547     }
3548   }
3549   st->print(BULLET"method ordering:   "); method_ordering()->print_value_on(st);      st->cr();
3550   if (default_methods() != nullptr) {
3551     st->print(BULLET"default_methods:   "); default_methods()->print_value_on(st);    st->cr();
3552     if (Verbose) {
3553       Array<Method*>* method_array = default_methods();
3554       for (int i = 0; i < method_array->length(); i++) {
3555         st->print("%d : ", i); method_array->at(i)->print_value(); st->cr();
3556       }
3557     }
3558   }
3559   if (default_vtable_indices() != nullptr) {
3560     st->print(BULLET"default vtable indices:   "); default_vtable_indices()->print_value_on(st);       st->cr();
3561   }
3562   st->print(BULLET"local interfaces:  "); local_interfaces()->print_value_on(st);      st->cr();
3563   st->print(BULLET"trans. interfaces: "); transitive_interfaces()->print_value_on(st); st->cr();
3564 
3565   st->print(BULLET"secondary supers: "); secondary_supers()->print_value_on(st); st->cr();
3566   if (UseSecondarySupersTable) {
3567     st->print(BULLET"hash_slot:         %d", hash_slot()); st->cr();
3568     st->print(BULLET"bitmap:            " UINTX_FORMAT_X_0, _bitmap); st->cr();
3569   }
3570   if (secondary_supers() != nullptr) {
3571     if (Verbose) {
3572       bool is_hashed = UseSecondarySupersTable && (_bitmap != SECONDARY_SUPERS_BITMAP_FULL);
3573       st->print_cr(BULLET"---- secondary supers (%d words):", _secondary_supers->length());
3574       for (int i = 0; i < _secondary_supers->length(); i++) {
3575         ResourceMark rm; // for external_name()
3576         Klass* secondary_super = _secondary_supers->at(i);
3577         st->print(BULLET"%2d:", i);
3578         if (is_hashed) {
3579           int home_slot = compute_home_slot(secondary_super, _bitmap);
3580           int distance = (i - home_slot) & SECONDARY_SUPERS_TABLE_MASK;
3581           st->print(" dist:%02d:", distance);
3582         }
3583         st->print_cr(" %p %s", secondary_super, secondary_super->external_name());
3584       }
3585     }
3586   }
3587   st->print(BULLET"constants:         "); constants()->print_value_on(st);         st->cr();
3588   if (class_loader_data() != nullptr) {
3589     st->print(BULLET"class loader data:  ");
3590     class_loader_data()->print_value_on(st);
3591     st->cr();
3592   }
3593   if (source_file_name() != nullptr) {
3594     st->print(BULLET"source file:       ");
3595     source_file_name()->print_value_on(st);
3596     st->cr();
3597   }
3598   if (source_debug_extension() != nullptr) {
3599     st->print(BULLET"source debug extension:       ");
3600     st->print("%s", source_debug_extension());
3601     st->cr();
3602   }
3603   st->print(BULLET"class annotations:       "); class_annotations()->print_value_on(st); st->cr();
3604   st->print(BULLET"class type annotations:  "); class_type_annotations()->print_value_on(st); st->cr();
3605   st->print(BULLET"field annotations:       "); fields_annotations()->print_value_on(st); st->cr();
3606   st->print(BULLET"field type annotations:  "); fields_type_annotations()->print_value_on(st); st->cr();
3607   {
3608     bool have_pv = false;
3609     // previous versions are linked together through the InstanceKlass
3610     for (InstanceKlass* pv_node = previous_versions();
3611          pv_node != nullptr;
3612          pv_node = pv_node->previous_versions()) {
3613       if (!have_pv)
3614         st->print(BULLET"previous version:  ");
3615       have_pv = true;
3616       pv_node->constants()->print_value_on(st);
3617     }
3618     if (have_pv) st->cr();
3619   }
3620 
3621   if (generic_signature() != nullptr) {
3622     st->print(BULLET"generic signature: ");
3623     generic_signature()->print_value_on(st);
3624     st->cr();
3625   }
3626   st->print(BULLET"inner classes:     "); inner_classes()->print_value_on(st);     st->cr();
3627   st->print(BULLET"nest members:     "); nest_members()->print_value_on(st);     st->cr();
3628   if (record_components() != nullptr) {
3629     st->print(BULLET"record components:     "); record_components()->print_value_on(st);     st->cr();
3630   }
3631   st->print(BULLET"permitted subclasses:     "); permitted_subclasses()->print_value_on(st);     st->cr();
3632   if (java_mirror() != nullptr) {
3633     st->print(BULLET"java mirror:       ");
3634     java_mirror()->print_value_on(st);
3635     st->cr();
3636   } else {
3637     st->print_cr(BULLET"java mirror:       null");
3638   }
3639   st->print(BULLET"vtable length      %d  (start addr: " PTR_FORMAT ")", vtable_length(), p2i(start_of_vtable())); st->cr();
3640   if (vtable_length() > 0 && (Verbose || WizardMode))  print_vtable(start_of_vtable(), vtable_length(), st);
3641   st->print(BULLET"itable length      %d (start addr: " PTR_FORMAT ")", itable_length(), p2i(start_of_itable())); st->cr();
3642   if (itable_length() > 0 && (Verbose || WizardMode))  print_vtable(start_of_itable(), itable_length(), st);
3643   st->print_cr(BULLET"---- static fields (%d words):", static_field_size());
3644 
3645   FieldPrinter print_static_field(st);
3646   ((InstanceKlass*)this)->do_local_static_fields(&print_static_field);
3647   st->print_cr(BULLET"---- non-static fields (%d words):", nonstatic_field_size());
3648   FieldPrinter print_nonstatic_field(st);
3649   InstanceKlass* ik = const_cast<InstanceKlass*>(this);
3650   ik->print_nonstatic_fields(&print_nonstatic_field);
3651 
3652   st->print(BULLET"non-static oop maps: ");
3653   OopMapBlock* map     = start_of_nonstatic_oop_maps();
3654   OopMapBlock* end_map = map + nonstatic_oop_map_count();
3655   while (map < end_map) {
3656     st->print("%d-%d ", map->offset(), map->offset() + heapOopSize*(map->count() - 1));
3657     map++;
3658   }
3659   st->cr();
3660 }
3661 
3662 void InstanceKlass::print_value_on(outputStream* st) const {
3663   assert(is_klass(), "must be klass");
3664   if (Verbose || WizardMode)  access_flags().print_on(st);
3665   name()->print_value_on(st);
3666 }
3667 
3668 void FieldPrinter::do_field(fieldDescriptor* fd) {
3669   _st->print(BULLET);
3670    if (_obj == nullptr) {
3671      fd->print_on(_st);
3672      _st->cr();
3673    } else {
3674      fd->print_on_for(_st, _obj);
3675      _st->cr();
3676    }
3677 }
3678 
3679 
3680 void InstanceKlass::oop_print_on(oop obj, outputStream* st) {
3681   Klass::oop_print_on(obj, st);
3682 
3683   if (this == vmClasses::String_klass()) {
3684     typeArrayOop value  = java_lang_String::value(obj);
3685     juint        length = java_lang_String::length(obj);
3686     if (value != nullptr &&
3687         value->is_typeArray() &&
3688         length <= (juint) value->length()) {
3689       st->print(BULLET"string: ");
3690       java_lang_String::print(obj, st);
3691       st->cr();
3692     }
3693   }
3694 
3695   st->print_cr(BULLET"---- fields (total size " SIZE_FORMAT " words):", oop_size(obj));
3696   FieldPrinter print_field(st, obj);
3697   print_nonstatic_fields(&print_field);
3698 
3699   if (this == vmClasses::Class_klass()) {
3700     st->print(BULLET"signature: ");
3701     java_lang_Class::print_signature(obj, st);
3702     st->cr();
3703     Klass* real_klass = java_lang_Class::as_Klass(obj);
3704     if (real_klass != nullptr && real_klass->is_instance_klass()) {
3705       st->print_cr(BULLET"---- static fields (%d):", java_lang_Class::static_oop_field_count(obj));
3706       InstanceKlass::cast(real_klass)->do_local_static_fields(&print_field);
3707     }
3708   } else if (this == vmClasses::MethodType_klass()) {
3709     st->print(BULLET"signature: ");
3710     java_lang_invoke_MethodType::print_signature(obj, st);
3711     st->cr();
3712   }
3713 }
3714 
3715 #ifndef PRODUCT
3716 
3717 bool InstanceKlass::verify_itable_index(int i) {
3718   int method_count = klassItable::method_count_for_interface(this);
3719   assert(i >= 0 && i < method_count, "index out of bounds");
3720   return true;
3721 }
3722 
3723 #endif //PRODUCT
3724 
3725 void InstanceKlass::oop_print_value_on(oop obj, outputStream* st) {
3726   st->print("a ");
3727   name()->print_value_on(st);
3728   obj->print_address_on(st);
3729   if (this == vmClasses::String_klass()
3730       && java_lang_String::value(obj) != nullptr) {
3731     ResourceMark rm;
3732     int len = java_lang_String::length(obj);
3733     int plen = (len < 24 ? len : 12);
3734     char* str = java_lang_String::as_utf8_string(obj, 0, plen);
3735     st->print(" = \"%s\"", str);
3736     if (len > plen)
3737       st->print("...[%d]", len);
3738   } else if (this == vmClasses::Class_klass()) {
3739     Klass* k = java_lang_Class::as_Klass(obj);
3740     st->print(" = ");
3741     if (k != nullptr) {
3742       k->print_value_on(st);
3743     } else {
3744       const char* tname = type2name(java_lang_Class::primitive_type(obj));
3745       st->print("%s", tname ? tname : "type?");
3746     }
3747   } else if (this == vmClasses::MethodType_klass()) {
3748     st->print(" = ");
3749     java_lang_invoke_MethodType::print_signature(obj, st);
3750   } else if (java_lang_boxing_object::is_instance(obj)) {
3751     st->print(" = ");
3752     java_lang_boxing_object::print(obj, st);
3753   } else if (this == vmClasses::LambdaForm_klass()) {
3754     oop vmentry = java_lang_invoke_LambdaForm::vmentry(obj);
3755     if (vmentry != nullptr) {
3756       st->print(" => ");
3757       vmentry->print_value_on(st);
3758     }
3759   } else if (this == vmClasses::MemberName_klass()) {
3760     Metadata* vmtarget = java_lang_invoke_MemberName::vmtarget(obj);
3761     if (vmtarget != nullptr) {
3762       st->print(" = ");
3763       vmtarget->print_value_on(st);
3764     } else {
3765       oop clazz = java_lang_invoke_MemberName::clazz(obj);
3766       oop name  = java_lang_invoke_MemberName::name(obj);
3767       if (clazz != nullptr) {
3768         clazz->print_value_on(st);
3769       } else {
3770         st->print("null");
3771       }
3772       st->print(".");
3773       if (name != nullptr) {
3774         name->print_value_on(st);
3775       } else {
3776         st->print("null");
3777       }
3778     }
3779   }
3780 }
3781 
3782 const char* InstanceKlass::internal_name() const {
3783   return external_name();
3784 }
3785 
3786 void InstanceKlass::print_class_load_logging(ClassLoaderData* loader_data,
3787                                              const ModuleEntry* module_entry,
3788                                              const ClassFileStream* cfs) const {
3789 
3790   if (ClassListWriter::is_enabled()) {
3791     ClassListWriter::write(this, cfs);
3792   }
3793 
3794   print_class_load_helper(loader_data, module_entry, cfs);
3795   print_class_load_cause_logging();
3796 }
3797 
3798 void InstanceKlass::print_class_load_helper(ClassLoaderData* loader_data,
3799                                              const ModuleEntry* module_entry,
3800                                              const ClassFileStream* cfs) const {
3801 
3802   if (!log_is_enabled(Info, class, load)) {
3803     return;
3804   }
3805 
3806   ResourceMark rm;
3807   LogMessage(class, load) msg;
3808   stringStream info_stream;
3809 
3810   // Name and class hierarchy info
3811   info_stream.print("%s", external_name());
3812 
3813   // Source
3814   if (cfs != nullptr) {
3815     if (cfs->source() != nullptr) {
3816       const char* module_name = (module_entry->name() == nullptr) ? UNNAMED_MODULE : module_entry->name()->as_C_string();
3817       if (module_name != nullptr) {
3818         // When the boot loader created the stream, it didn't know the module name
3819         // yet. Let's format it now.
3820         if (cfs->from_boot_loader_modules_image()) {
3821           info_stream.print(" source: jrt:/%s", module_name);
3822         } else {
3823           info_stream.print(" source: %s", cfs->source());
3824         }
3825       } else {
3826         info_stream.print(" source: %s", cfs->source());
3827       }
3828     } else if (loader_data == ClassLoaderData::the_null_class_loader_data()) {
3829       Thread* current = Thread::current();
3830       Klass* caller = current->is_Java_thread() ?
3831         JavaThread::cast(current)->security_get_caller_class(1):
3832         nullptr;
3833       // caller can be null, for example, during a JVMTI VM_Init hook
3834       if (caller != nullptr) {
3835         info_stream.print(" source: instance of %s", caller->external_name());
3836       } else {
3837         // source is unknown
3838       }
3839     } else {
3840       oop class_loader = loader_data->class_loader();
3841       info_stream.print(" source: %s", class_loader->klass()->external_name());
3842     }
3843   } else {
3844     assert(this->is_shared(), "must be");
3845     if (MetaspaceShared::is_shared_dynamic((void*)this)) {
3846       info_stream.print(" source: shared objects file (top)");
3847     } else {
3848       info_stream.print(" source: shared objects file");
3849     }
3850   }
3851 
3852   msg.info("%s", info_stream.as_string());
3853 
3854   if (log_is_enabled(Debug, class, load)) {
3855     stringStream debug_stream;
3856 
3857     // Class hierarchy info
3858     debug_stream.print(" klass: " PTR_FORMAT " super: " PTR_FORMAT,
3859                        p2i(this),  p2i(superklass()));
3860 
3861     // Interfaces
3862     if (local_interfaces() != nullptr && local_interfaces()->length() > 0) {
3863       debug_stream.print(" interfaces:");
3864       int length = local_interfaces()->length();
3865       for (int i = 0; i < length; i++) {
3866         debug_stream.print(" " PTR_FORMAT,
3867                            p2i(InstanceKlass::cast(local_interfaces()->at(i))));
3868       }
3869     }
3870 
3871     // Class loader
3872     debug_stream.print(" loader: [");
3873     loader_data->print_value_on(&debug_stream);
3874     debug_stream.print("]");
3875 
3876     // Classfile checksum
3877     if (cfs) {
3878       debug_stream.print(" bytes: %d checksum: %08x",
3879                          cfs->length(),
3880                          ClassLoader::crc32(0, (const char*)cfs->buffer(),
3881                          cfs->length()));
3882     }
3883 
3884     msg.debug("%s", debug_stream.as_string());
3885   }
3886 }
3887 
3888 void InstanceKlass::print_class_load_cause_logging() const {
3889   bool log_cause_native = log_is_enabled(Info, class, load, cause, native);
3890   if (log_cause_native || log_is_enabled(Info, class, load, cause)) {
3891     JavaThread* current = JavaThread::current();
3892     ResourceMark rm(current);
3893     const char* name = external_name();
3894 
3895     if (LogClassLoadingCauseFor == nullptr ||
3896         (strcmp("*", LogClassLoadingCauseFor) != 0 &&
3897          strstr(name, LogClassLoadingCauseFor) == nullptr)) {
3898         return;
3899     }
3900 
3901     // Log Java stack first
3902     {
3903       LogMessage(class, load, cause) msg;
3904       NonInterleavingLogStream info_stream{LogLevelType::Info, msg};
3905 
3906       info_stream.print_cr("Java stack when loading %s:", name);
3907       current->print_stack_on(&info_stream);
3908     }
3909 
3910     // Log native stack second
3911     if (log_cause_native) {
3912       // Log to string first so that lines can be indented
3913       stringStream stack_stream;
3914       char buf[O_BUFLEN];
3915       address lastpc = nullptr;
3916       if (os::platform_print_native_stack(&stack_stream, nullptr, buf, O_BUFLEN, lastpc)) {
3917         // We have printed the native stack in platform-specific code,
3918         // so nothing else to do in this case.
3919       } else {
3920         frame f = os::current_frame();
3921         VMError::print_native_stack(&stack_stream, f, current, true /*print_source_info */,
3922                                     -1 /* max stack_stream */, buf, O_BUFLEN);
3923       }
3924 
3925       LogMessage(class, load, cause, native) msg;
3926       NonInterleavingLogStream info_stream{LogLevelType::Info, msg};
3927       info_stream.print_cr("Native stack when loading %s:", name);
3928 
3929       // Print each native stack line to the log
3930       int size = (int) stack_stream.size();
3931       char* stack = stack_stream.as_string();
3932       char* stack_end = stack + size;
3933       char* line_start = stack;
3934       for (char* p = stack; p < stack_end; p++) {
3935         if (*p == '\n') {
3936           *p = '\0';
3937           info_stream.print_cr("\t%s", line_start);
3938           line_start = p + 1;
3939         }
3940       }
3941       if (line_start < stack_end) {
3942         info_stream.print_cr("\t%s", line_start);
3943       }
3944     }
3945   }
3946 }
3947 
3948 // Verification
3949 
3950 class VerifyFieldClosure: public BasicOopIterateClosure {
3951  protected:
3952   template <class T> void do_oop_work(T* p) {
3953     oop obj = RawAccess<>::oop_load(p);
3954     if (!oopDesc::is_oop_or_null(obj)) {
3955       tty->print_cr("Failed: " PTR_FORMAT " -> " PTR_FORMAT, p2i(p), p2i(obj));
3956       Universe::print_on(tty);
3957       guarantee(false, "boom");
3958     }
3959   }
3960  public:
3961   virtual void do_oop(oop* p)       { VerifyFieldClosure::do_oop_work(p); }
3962   virtual void do_oop(narrowOop* p) { VerifyFieldClosure::do_oop_work(p); }
3963 };
3964 
3965 void InstanceKlass::verify_on(outputStream* st) {
3966 #ifndef PRODUCT
3967   // Avoid redundant verifies, this really should be in product.
3968   if (_verify_count == Universe::verify_count()) return;
3969   _verify_count = Universe::verify_count();
3970 #endif
3971 
3972   // Verify Klass
3973   Klass::verify_on(st);
3974 
3975   // Verify that klass is present in ClassLoaderData
3976   guarantee(class_loader_data()->contains_klass(this),
3977             "this class isn't found in class loader data");
3978 
3979   // Verify vtables
3980   if (is_linked()) {
3981     // $$$ This used to be done only for m/s collections.  Doing it
3982     // always seemed a valid generalization.  (DLD -- 6/00)
3983     vtable().verify(st);
3984   }
3985 
3986   // Verify first subklass
3987   if (subklass() != nullptr) {
3988     guarantee(subklass()->is_klass(), "should be klass");
3989   }
3990 
3991   // Verify siblings
3992   Klass* super = this->super();
3993   Klass* sib = next_sibling();
3994   if (sib != nullptr) {
3995     if (sib == this) {
3996       fatal("subclass points to itself " PTR_FORMAT, p2i(sib));
3997     }
3998 
3999     guarantee(sib->is_klass(), "should be klass");
4000     guarantee(sib->super() == super, "siblings should have same superklass");
4001   }
4002 
4003   // Verify local interfaces
4004   if (local_interfaces()) {
4005     Array<InstanceKlass*>* local_interfaces = this->local_interfaces();
4006     for (int j = 0; j < local_interfaces->length(); j++) {
4007       InstanceKlass* e = local_interfaces->at(j);
4008       guarantee(e->is_klass() && e->is_interface(), "invalid local interface");
4009     }
4010   }
4011 
4012   // Verify transitive interfaces
4013   if (transitive_interfaces() != nullptr) {
4014     Array<InstanceKlass*>* transitive_interfaces = this->transitive_interfaces();
4015     for (int j = 0; j < transitive_interfaces->length(); j++) {
4016       InstanceKlass* e = transitive_interfaces->at(j);
4017       guarantee(e->is_klass() && e->is_interface(), "invalid transitive interface");
4018     }
4019   }
4020 
4021   // Verify methods
4022   if (methods() != nullptr) {
4023     Array<Method*>* methods = this->methods();
4024     for (int j = 0; j < methods->length(); j++) {
4025       guarantee(methods->at(j)->is_method(), "non-method in methods array");
4026     }
4027     for (int j = 0; j < methods->length() - 1; j++) {
4028       Method* m1 = methods->at(j);
4029       Method* m2 = methods->at(j + 1);
4030       guarantee(m1->name()->fast_compare(m2->name()) <= 0, "methods not sorted correctly");
4031     }
4032   }
4033 
4034   // Verify method ordering
4035   if (method_ordering() != nullptr) {
4036     Array<int>* method_ordering = this->method_ordering();
4037     int length = method_ordering->length();
4038     if (JvmtiExport::can_maintain_original_method_order() ||
4039         ((CDSConfig::is_using_archive() || CDSConfig::is_dumping_archive()) && length != 0)) {
4040       guarantee(length == methods()->length(), "invalid method ordering length");
4041       jlong sum = 0;
4042       for (int j = 0; j < length; j++) {
4043         int original_index = method_ordering->at(j);
4044         guarantee(original_index >= 0, "invalid method ordering index");
4045         guarantee(original_index < length, "invalid method ordering index");
4046         sum += original_index;
4047       }
4048       // Verify sum of indices 0,1,...,length-1
4049       guarantee(sum == ((jlong)length*(length-1))/2, "invalid method ordering sum");
4050     } else {
4051       guarantee(length == 0, "invalid method ordering length");
4052     }
4053   }
4054 
4055   // Verify default methods
4056   if (default_methods() != nullptr) {
4057     Array<Method*>* methods = this->default_methods();
4058     for (int j = 0; j < methods->length(); j++) {
4059       guarantee(methods->at(j)->is_method(), "non-method in methods array");
4060     }
4061     for (int j = 0; j < methods->length() - 1; j++) {
4062       Method* m1 = methods->at(j);
4063       Method* m2 = methods->at(j + 1);
4064       guarantee(m1->name()->fast_compare(m2->name()) <= 0, "methods not sorted correctly");
4065     }
4066   }
4067 
4068   // Verify JNI static field identifiers
4069   if (jni_ids() != nullptr) {
4070     jni_ids()->verify(this);
4071   }
4072 
4073   // Verify other fields
4074   if (constants() != nullptr) {
4075     guarantee(constants()->is_constantPool(), "should be constant pool");
4076   }
4077 }
4078 
4079 void InstanceKlass::oop_verify_on(oop obj, outputStream* st) {
4080   Klass::oop_verify_on(obj, st);
4081   VerifyFieldClosure blk;
4082   obj->oop_iterate(&blk);
4083 }
4084 
4085 
4086 // JNIid class for jfieldIDs only
4087 // Note to reviewers:
4088 // These JNI functions are just moved over to column 1 and not changed
4089 // in the compressed oops workspace.
4090 JNIid::JNIid(Klass* holder, int offset, JNIid* next) {
4091   _holder = holder;
4092   _offset = offset;
4093   _next = next;
4094   debug_only(_is_static_field_id = false;)
4095 }
4096 
4097 
4098 JNIid* JNIid::find(int offset) {
4099   JNIid* current = this;
4100   while (current != nullptr) {
4101     if (current->offset() == offset) return current;
4102     current = current->next();
4103   }
4104   return nullptr;
4105 }
4106 
4107 void JNIid::deallocate(JNIid* current) {
4108   while (current != nullptr) {
4109     JNIid* next = current->next();
4110     delete current;
4111     current = next;
4112   }
4113 }
4114 
4115 
4116 void JNIid::verify(Klass* holder) {
4117   int first_field_offset  = InstanceMirrorKlass::offset_of_static_fields();
4118   int end_field_offset;
4119   end_field_offset = first_field_offset + (InstanceKlass::cast(holder)->static_field_size() * wordSize);
4120 
4121   JNIid* current = this;
4122   while (current != nullptr) {
4123     guarantee(current->holder() == holder, "Invalid klass in JNIid");
4124 #ifdef ASSERT
4125     int o = current->offset();
4126     if (current->is_static_field_id()) {
4127       guarantee(o >= first_field_offset  && o < end_field_offset,  "Invalid static field offset in JNIid");
4128     }
4129 #endif
4130     current = current->next();
4131   }
4132 }
4133 
4134 void InstanceKlass::set_init_state(ClassState state) {
4135   if (state > loaded) {
4136     assert_lock_strong(_init_monitor);
4137   }
4138 #ifdef ASSERT
4139   bool good_state = is_shared() ? (_init_state <= state)
4140                                                : (_init_state < state);
4141   bool link_failed = _init_state == being_linked && state == loaded;
4142   assert(good_state || state == allocated || link_failed, "illegal state transition");
4143 #endif
4144   assert(_init_thread == nullptr, "should be cleared before state change");
4145   Atomic::store(&_init_state, state);
4146 }
4147 
4148 #if INCLUDE_JVMTI
4149 
4150 // RedefineClasses() support for previous versions
4151 
4152 // Globally, there is at least one previous version of a class to walk
4153 // during class unloading, which is saved because old methods in the class
4154 // are still running.   Otherwise the previous version list is cleaned up.
4155 bool InstanceKlass::_should_clean_previous_versions = false;
4156 
4157 // Returns true if there are previous versions of a class for class
4158 // unloading only. Also resets the flag to false. purge_previous_version
4159 // will set the flag to true if there are any left, i.e., if there's any
4160 // work to do for next time. This is to avoid the expensive code cache
4161 // walk in CLDG::clean_deallocate_lists().
4162 bool InstanceKlass::should_clean_previous_versions_and_reset() {
4163   bool ret = _should_clean_previous_versions;
4164   log_trace(redefine, class, iklass, purge)("Class unloading: should_clean_previous_versions = %s",
4165      ret ? "true" : "false");
4166   _should_clean_previous_versions = false;
4167   return ret;
4168 }
4169 
4170 // This nulls out jmethodIDs for all methods in 'klass'
4171 // It needs to be called explicitly for all previous versions of a class because these may not be cleaned up
4172 // during class unloading.
4173 // We can not use the jmethodID cache associated with klass directly because the 'previous' versions
4174 // do not have the jmethodID cache filled in. Instead, we need to lookup jmethodID for each method and this
4175 // is expensive - O(n) for one jmethodID lookup. For all contained methods it is O(n^2).
4176 // The reason for expensive jmethodID lookup for each method is that there is no direct link between method and jmethodID.
4177 void InstanceKlass::clear_jmethod_ids(InstanceKlass* klass) {
4178   Array<Method*>* method_refs = klass->methods();
4179   for (int k = 0; k < method_refs->length(); k++) {
4180     Method* method = method_refs->at(k);
4181     if (method != nullptr && method->is_obsolete()) {
4182       method->clear_jmethod_id();
4183     }
4184   }
4185 }
4186 
4187 // Purge previous versions before adding new previous versions of the class and
4188 // during class unloading.
4189 void InstanceKlass::purge_previous_version_list() {
4190   assert(SafepointSynchronize::is_at_safepoint(), "only called at safepoint");
4191   assert(has_been_redefined(), "Should only be called for main class");
4192 
4193   // Quick exit.
4194   if (previous_versions() == nullptr) {
4195     return;
4196   }
4197 
4198   // This klass has previous versions so see what we can cleanup
4199   // while it is safe to do so.
4200 
4201   int deleted_count = 0;    // leave debugging breadcrumbs
4202   int live_count = 0;
4203   ClassLoaderData* loader_data = class_loader_data();
4204   assert(loader_data != nullptr, "should never be null");
4205 
4206   ResourceMark rm;
4207   log_trace(redefine, class, iklass, purge)("%s: previous versions", external_name());
4208 
4209   // previous versions are linked together through the InstanceKlass
4210   InstanceKlass* pv_node = previous_versions();
4211   InstanceKlass* last = this;
4212   int version = 0;
4213 
4214   // check the previous versions list
4215   for (; pv_node != nullptr; ) {
4216 
4217     ConstantPool* pvcp = pv_node->constants();
4218     assert(pvcp != nullptr, "cp ref was unexpectedly cleared");
4219 
4220     if (!pvcp->on_stack()) {
4221       // If the constant pool isn't on stack, none of the methods
4222       // are executing.  Unlink this previous_version.
4223       // The previous version InstanceKlass is on the ClassLoaderData deallocate list
4224       // so will be deallocated during the next phase of class unloading.
4225       log_trace(redefine, class, iklass, purge)
4226         ("previous version " PTR_FORMAT " is dead.", p2i(pv_node));
4227       // Unlink from previous version list.
4228       assert(pv_node->class_loader_data() == loader_data, "wrong loader_data");
4229       InstanceKlass* next = pv_node->previous_versions();
4230       clear_jmethod_ids(pv_node); // jmethodID maintenance for the unloaded class
4231       pv_node->link_previous_versions(nullptr);   // point next to null
4232       last->link_previous_versions(next);
4233       // Delete this node directly. Nothing is referring to it and we don't
4234       // want it to increase the counter for metadata to delete in CLDG.
4235       MetadataFactory::free_metadata(loader_data, pv_node);
4236       pv_node = next;
4237       deleted_count++;
4238       version++;
4239       continue;
4240     } else {
4241       assert(pvcp->pool_holder() != nullptr, "Constant pool with no holder");
4242       guarantee (!loader_data->is_unloading(), "unloaded classes can't be on the stack");
4243       live_count++;
4244       if (pvcp->is_shared()) {
4245         // Shared previous versions can never be removed so no cleaning is needed.
4246         log_trace(redefine, class, iklass, purge)("previous version " PTR_FORMAT " is shared", p2i(pv_node));
4247       } else {
4248         // Previous version alive, set that clean is needed for next time.
4249         _should_clean_previous_versions = true;
4250         log_trace(redefine, class, iklass, purge)("previous version " PTR_FORMAT " is alive", p2i(pv_node));
4251       }
4252     }
4253 
4254     // next previous version
4255     last = pv_node;
4256     pv_node = pv_node->previous_versions();
4257     version++;
4258   }
4259   log_trace(redefine, class, iklass, purge)
4260     ("previous version stats: live=%d, deleted=%d", live_count, deleted_count);
4261 }
4262 
4263 void InstanceKlass::mark_newly_obsolete_methods(Array<Method*>* old_methods,
4264                                                 int emcp_method_count) {
4265   int obsolete_method_count = old_methods->length() - emcp_method_count;
4266 
4267   if (emcp_method_count != 0 && obsolete_method_count != 0 &&
4268       _previous_versions != nullptr) {
4269     // We have a mix of obsolete and EMCP methods so we have to
4270     // clear out any matching EMCP method entries the hard way.
4271     int local_count = 0;
4272     for (int i = 0; i < old_methods->length(); i++) {
4273       Method* old_method = old_methods->at(i);
4274       if (old_method->is_obsolete()) {
4275         // only obsolete methods are interesting
4276         Symbol* m_name = old_method->name();
4277         Symbol* m_signature = old_method->signature();
4278 
4279         // previous versions are linked together through the InstanceKlass
4280         int j = 0;
4281         for (InstanceKlass* prev_version = _previous_versions;
4282              prev_version != nullptr;
4283              prev_version = prev_version->previous_versions(), j++) {
4284 
4285           Array<Method*>* method_refs = prev_version->methods();
4286           for (int k = 0; k < method_refs->length(); k++) {
4287             Method* method = method_refs->at(k);
4288 
4289             if (!method->is_obsolete() &&
4290                 method->name() == m_name &&
4291                 method->signature() == m_signature) {
4292               // The current RedefineClasses() call has made all EMCP
4293               // versions of this method obsolete so mark it as obsolete
4294               log_trace(redefine, class, iklass, add)
4295                 ("%s(%s): flush obsolete method @%d in version @%d",
4296                  m_name->as_C_string(), m_signature->as_C_string(), k, j);
4297 
4298               method->set_is_obsolete();
4299               break;
4300             }
4301           }
4302 
4303           // The previous loop may not find a matching EMCP method, but
4304           // that doesn't mean that we can optimize and not go any
4305           // further back in the PreviousVersion generations. The EMCP
4306           // method for this generation could have already been made obsolete,
4307           // but there still may be an older EMCP method that has not
4308           // been made obsolete.
4309         }
4310 
4311         if (++local_count >= obsolete_method_count) {
4312           // no more obsolete methods so bail out now
4313           break;
4314         }
4315       }
4316     }
4317   }
4318 }
4319 
4320 // Save the scratch_class as the previous version if any of the methods are running.
4321 // The previous_versions are used to set breakpoints in EMCP methods and they are
4322 // also used to clean MethodData links to redefined methods that are no longer running.
4323 void InstanceKlass::add_previous_version(InstanceKlass* scratch_class,
4324                                          int emcp_method_count) {
4325   assert(Thread::current()->is_VM_thread(),
4326          "only VMThread can add previous versions");
4327 
4328   ResourceMark rm;
4329   log_trace(redefine, class, iklass, add)
4330     ("adding previous version ref for %s, EMCP_cnt=%d", scratch_class->external_name(), emcp_method_count);
4331 
4332   // Clean out old previous versions for this class
4333   purge_previous_version_list();
4334 
4335   // Mark newly obsolete methods in remaining previous versions.  An EMCP method from
4336   // a previous redefinition may be made obsolete by this redefinition.
4337   Array<Method*>* old_methods = scratch_class->methods();
4338   mark_newly_obsolete_methods(old_methods, emcp_method_count);
4339 
4340   // If the constant pool for this previous version of the class
4341   // is not marked as being on the stack, then none of the methods
4342   // in this previous version of the class are on the stack so
4343   // we don't need to add this as a previous version.
4344   ConstantPool* cp_ref = scratch_class->constants();
4345   if (!cp_ref->on_stack()) {
4346     log_trace(redefine, class, iklass, add)("scratch class not added; no methods are running");
4347     scratch_class->class_loader_data()->add_to_deallocate_list(scratch_class);
4348     return;
4349   }
4350 
4351   // Add previous version if any methods are still running or if this is
4352   // a shared class which should never be removed.
4353   assert(scratch_class->previous_versions() == nullptr, "shouldn't have a previous version");
4354   scratch_class->link_previous_versions(previous_versions());
4355   link_previous_versions(scratch_class);
4356   if (cp_ref->is_shared()) {
4357     log_trace(redefine, class, iklass, add) ("scratch class added; class is shared");
4358   } else {
4359     //  We only set clean_previous_versions flag for processing during class
4360     // unloading for non-shared classes.
4361     _should_clean_previous_versions = true;
4362     log_trace(redefine, class, iklass, add) ("scratch class added; one of its methods is on_stack.");
4363   }
4364 } // end add_previous_version()
4365 
4366 #endif // INCLUDE_JVMTI
4367 
4368 Method* InstanceKlass::method_with_idnum(int idnum) {
4369   Method* m = nullptr;
4370   if (idnum < methods()->length()) {
4371     m = methods()->at(idnum);
4372   }
4373   if (m == nullptr || m->method_idnum() != idnum) {
4374     for (int index = 0; index < methods()->length(); ++index) {
4375       m = methods()->at(index);
4376       if (m->method_idnum() == idnum) {
4377         return m;
4378       }
4379     }
4380     // None found, return null for the caller to handle.
4381     return nullptr;
4382   }
4383   return m;
4384 }
4385 
4386 
4387 Method* InstanceKlass::method_with_orig_idnum(int idnum) {
4388   if (idnum >= methods()->length()) {
4389     return nullptr;
4390   }
4391   Method* m = methods()->at(idnum);
4392   if (m != nullptr && m->orig_method_idnum() == idnum) {
4393     return m;
4394   }
4395   // Obsolete method idnum does not match the original idnum
4396   for (int index = 0; index < methods()->length(); ++index) {
4397     m = methods()->at(index);
4398     if (m->orig_method_idnum() == idnum) {
4399       return m;
4400     }
4401   }
4402   // None found, return null for the caller to handle.
4403   return nullptr;
4404 }
4405 
4406 
4407 Method* InstanceKlass::method_with_orig_idnum(int idnum, int version) {
4408   InstanceKlass* holder = get_klass_version(version);
4409   if (holder == nullptr) {
4410     return nullptr; // The version of klass is gone, no method is found
4411   }
4412   Method* method = holder->method_with_orig_idnum(idnum);
4413   return method;
4414 }
4415 
4416 #if INCLUDE_JVMTI
4417 JvmtiCachedClassFileData* InstanceKlass::get_cached_class_file() {
4418   return _cached_class_file;
4419 }
4420 
4421 jint InstanceKlass::get_cached_class_file_len() {
4422   return VM_RedefineClasses::get_cached_class_file_len(_cached_class_file);
4423 }
4424 
4425 unsigned char * InstanceKlass::get_cached_class_file_bytes() {
4426   return VM_RedefineClasses::get_cached_class_file_bytes(_cached_class_file);
4427 }
4428 #endif
4429 
4430 // Make a step iterating over the class hierarchy under the root class.
4431 // Skips subclasses if requested.
4432 void ClassHierarchyIterator::next() {
4433   assert(_current != nullptr, "required");
4434   if (_visit_subclasses && _current->subklass() != nullptr) {
4435     _current = _current->subklass();
4436     return; // visit next subclass
4437   }
4438   _visit_subclasses = true; // reset
4439   while (_current->next_sibling() == nullptr && _current != _root) {
4440     _current = _current->superklass(); // backtrack; no more sibling subclasses left
4441   }
4442   if (_current == _root) {
4443     // Iteration is over (back at root after backtracking). Invalidate the iterator.
4444     _current = nullptr;
4445     return;
4446   }
4447   _current = _current->next_sibling();
4448   return; // visit next sibling subclass
4449 }