1 /*
   2  * Copyright (c) 1997, 2026, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "cds/aotClassInitializer.hpp"
  26 #include "cds/aotLinkedClassBulkLoader.hpp"
  27 #include "cds/aotMetaspace.hpp"
  28 #include "cds/archiveUtils.hpp"
  29 #include "cds/cdsConfig.hpp"
  30 #include "cds/cdsEnumKlass.hpp"
  31 #include "cds/classListWriter.hpp"
  32 #include "cds/heapShared.hpp"
  33 #include "classfile/classFileParser.hpp"
  34 #include "classfile/classFileStream.hpp"
  35 #include "classfile/classLoader.hpp"
  36 #include "classfile/classLoaderData.inline.hpp"
  37 #include "classfile/javaClasses.hpp"
  38 #include "classfile/moduleEntry.hpp"
  39 #include "classfile/systemDictionary.hpp"
  40 #include "classfile/systemDictionaryShared.hpp"
  41 #include "classfile/verifier.hpp"
  42 #include "classfile/vmClasses.hpp"
  43 #include "classfile/vmSymbols.hpp"
  44 #include "code/codeCache.hpp"
  45 #include "code/dependencyContext.hpp"
  46 #include "compiler/compilationPolicy.hpp"
  47 #include "compiler/compileBroker.hpp"
  48 #include "gc/shared/collectedHeap.inline.hpp"
  49 #include "interpreter/bytecodeHistogram.hpp"
  50 #include "interpreter/bytecodeStream.hpp"
  51 #include "interpreter/oopMapCache.hpp"
  52 #include "interpreter/rewriter.hpp"
  53 #include "jvm.h"
  54 #include "jvmtifiles/jvmti.h"
  55 #include "klass.inline.hpp"
  56 #include "logging/log.hpp"
  57 #include "logging/logMessage.hpp"
  58 #include "logging/logStream.hpp"
  59 #include "memory/allocation.inline.hpp"
  60 #include "memory/iterator.inline.hpp"
  61 #include "memory/metadataFactory.hpp"
  62 #include "memory/metaspaceClosure.hpp"
  63 #include "memory/oopFactory.hpp"
  64 #include "memory/resourceArea.hpp"
  65 #include "memory/universe.hpp"
  66 #include "oops/constantPool.hpp"
  67 #include "oops/fieldStreams.inline.hpp"
  68 #include "oops/instanceClassLoaderKlass.hpp"
  69 #include "oops/instanceKlass.inline.hpp"
  70 #include "oops/instanceMirrorKlass.hpp"
  71 #include "oops/instanceOop.hpp"
  72 #include "oops/instanceStackChunkKlass.hpp"
  73 #include "oops/klass.inline.hpp"
  74 #include "oops/method.hpp"
  75 #include "oops/oop.inline.hpp"
  76 #include "oops/recordComponent.hpp"
  77 #include "oops/symbol.hpp"
  78 #include "prims/jvmtiExport.hpp"
  79 #include "prims/jvmtiRedefineClasses.hpp"
  80 #include "prims/jvmtiThreadState.hpp"
  81 #include "prims/methodComparator.hpp"
  82 #include "runtime/arguments.hpp"
  83 #include "runtime/atomicAccess.hpp"
  84 #include "runtime/deoptimization.hpp"
  85 #include "runtime/fieldDescriptor.inline.hpp"
  86 #include "runtime/handles.inline.hpp"
  87 #include "runtime/javaCalls.hpp"
  88 #include "runtime/javaThread.inline.hpp"
  89 #include "runtime/mutexLocker.hpp"
  90 #include "runtime/orderAccess.hpp"
  91 #include "runtime/os.inline.hpp"
  92 #include "runtime/reflection.hpp"
  93 #include "runtime/runtimeUpcalls.hpp"
  94 #include "runtime/synchronizer.hpp"
  95 #include "runtime/threads.hpp"
  96 #include "services/classLoadingService.hpp"
  97 #include "services/finalizerService.hpp"
  98 #include "services/threadService.hpp"
  99 #include "utilities/dtrace.hpp"
 100 #include "utilities/events.hpp"
 101 #include "utilities/macros.hpp"
 102 #include "utilities/nativeStackPrinter.hpp"
 103 #include "utilities/stringUtils.hpp"
 104 #ifdef COMPILER1
 105 #include "c1/c1_Compiler.hpp"
 106 #endif
 107 #if INCLUDE_JFR
 108 #include "jfr/jfrEvents.hpp"
 109 #endif
 110 
 111 #ifdef DTRACE_ENABLED
 112 
 113 
 114 #define HOTSPOT_CLASS_INITIALIZATION_required HOTSPOT_CLASS_INITIALIZATION_REQUIRED
 115 #define HOTSPOT_CLASS_INITIALIZATION_recursive HOTSPOT_CLASS_INITIALIZATION_RECURSIVE
 116 #define HOTSPOT_CLASS_INITIALIZATION_concurrent HOTSPOT_CLASS_INITIALIZATION_CONCURRENT
 117 #define HOTSPOT_CLASS_INITIALIZATION_erroneous HOTSPOT_CLASS_INITIALIZATION_ERRONEOUS
 118 #define HOTSPOT_CLASS_INITIALIZATION_super__failed HOTSPOT_CLASS_INITIALIZATION_SUPER_FAILED
 119 #define HOTSPOT_CLASS_INITIALIZATION_clinit HOTSPOT_CLASS_INITIALIZATION_CLINIT
 120 #define HOTSPOT_CLASS_INITIALIZATION_error HOTSPOT_CLASS_INITIALIZATION_ERROR
 121 #define HOTSPOT_CLASS_INITIALIZATION_end HOTSPOT_CLASS_INITIALIZATION_END
 122 #define DTRACE_CLASSINIT_PROBE(type, thread_type)                \
 123   {                                                              \
 124     char* data = nullptr;                                        \
 125     int len = 0;                                                 \
 126     Symbol* clss_name = name();                                  \
 127     if (clss_name != nullptr) {                                  \
 128       data = (char*)clss_name->bytes();                          \
 129       len = clss_name->utf8_length();                            \
 130     }                                                            \
 131     HOTSPOT_CLASS_INITIALIZATION_##type(                         \
 132       data, len, (void*)class_loader(), thread_type);            \
 133   }
 134 
 135 #define DTRACE_CLASSINIT_PROBE_WAIT(type, thread_type, wait)     \
 136   {                                                              \
 137     char* data = nullptr;                                        \
 138     int len = 0;                                                 \
 139     Symbol* clss_name = name();                                  \
 140     if (clss_name != nullptr) {                                  \
 141       data = (char*)clss_name->bytes();                          \
 142       len = clss_name->utf8_length();                            \
 143     }                                                            \
 144     HOTSPOT_CLASS_INITIALIZATION_##type(                         \
 145       data, len, (void*)class_loader(), thread_type, wait);      \
 146   }
 147 
 148 #else //  ndef DTRACE_ENABLED
 149 
 150 #define DTRACE_CLASSINIT_PROBE(type, thread_type)
 151 #define DTRACE_CLASSINIT_PROBE_WAIT(type, thread_type, wait)
 152 
 153 #endif //  ndef DTRACE_ENABLED
 154 
 155 bool InstanceKlass::_finalization_enabled = true;
 156 static int call_class_initializer_counter = 0;   // for debugging
 157 
 158 static inline bool is_class_loader(const Symbol* class_name,
 159                                    const ClassFileParser& parser) {
 160   assert(class_name != nullptr, "invariant");
 161 
 162   if (class_name == vmSymbols::java_lang_ClassLoader()) {
 163     return true;
 164   }
 165 
 166   if (vmClasses::ClassLoader_klass_is_loaded()) {
 167     const Klass* const super_klass = parser.super_klass();
 168     if (super_klass != nullptr) {
 169       if (super_klass->is_subtype_of(vmClasses::ClassLoader_klass())) {
 170         return true;
 171       }
 172     }
 173   }
 174   return false;
 175 }
 176 
 177 static inline bool is_stack_chunk_class(const Symbol* class_name,
 178                                         const ClassLoaderData* loader_data) {
 179   return (class_name == vmSymbols::jdk_internal_vm_StackChunk() &&
 180           loader_data->is_the_null_class_loader_data());
 181 }
 182 
 183 // private: called to verify that k is a static member of this nest.
 184 // We know that k is an instance class in the same package and hence the
 185 // same classloader.
 186 bool InstanceKlass::has_nest_member(JavaThread* current, InstanceKlass* k) const {
 187   assert(!is_hidden(), "unexpected hidden class");
 188   if (_nest_members == nullptr || _nest_members == Universe::the_empty_short_array()) {
 189     if (log_is_enabled(Trace, class, nestmates)) {
 190       ResourceMark rm(current);
 191       log_trace(class, nestmates)("Checked nest membership of %s in non-nest-host class %s",
 192                                   k->external_name(), this->external_name());
 193     }
 194     return false;
 195   }
 196 
 197   if (log_is_enabled(Trace, class, nestmates)) {
 198     ResourceMark rm(current);
 199     log_trace(class, nestmates)("Checking nest membership of %s in %s",
 200                                 k->external_name(), this->external_name());
 201   }
 202 
 203   // Check for the named class in _nest_members.
 204   // We don't resolve, or load, any classes.
 205   for (int i = 0; i < _nest_members->length(); i++) {
 206     int cp_index = _nest_members->at(i);
 207     Symbol* name = _constants->klass_name_at(cp_index);
 208     if (name == k->name()) {
 209       log_trace(class, nestmates)("- named class found at nest_members[%d] => cp[%d]", i, cp_index);
 210       return true;
 211     }
 212   }
 213   log_trace(class, nestmates)("- class is NOT a nest member!");
 214   return false;
 215 }
 216 
 217 // Called to verify that k is a permitted subclass of this class.
 218 // The incoming stringStream is used to format the messages for error logging and for the caller
 219 // to use for exception throwing.
 220 bool InstanceKlass::has_as_permitted_subclass(const InstanceKlass* k, stringStream& ss) const {
 221   Thread* current = Thread::current();
 222   assert(k != nullptr, "sanity check");
 223   assert(_permitted_subclasses != nullptr && _permitted_subclasses != Universe::the_empty_short_array(),
 224          "unexpected empty _permitted_subclasses array");
 225 
 226   if (log_is_enabled(Trace, class, sealed)) {
 227     ResourceMark rm(current);
 228     log_trace(class, sealed)("Checking for permitted subclass %s in %s",
 229                              k->external_name(), this->external_name());
 230   }
 231 
 232   // Check that the class and its super are in the same module.
 233   if (k->module() != this->module()) {
 234     ss.print("Failed same module check: subclass %s is in module '%s' with loader %s, "
 235              "and sealed class %s is in module '%s' with loader %s",
 236              k->external_name(),
 237              k->module()->name_as_C_string(),
 238              k->module()->loader_data()->loader_name_and_id(),
 239              this->external_name(),
 240              this->module()->name_as_C_string(),
 241              this->module()->loader_data()->loader_name_and_id());
 242     log_trace(class, sealed)(" - %s", ss.as_string());
 243     return false;
 244   }
 245 
 246   if (!k->is_public() && !is_same_class_package(k)) {
 247     ss.print("Failed same package check: non-public subclass %s is in package '%s' with classloader %s, "
 248              "and sealed class %s is in package '%s' with classloader %s",
 249              k->external_name(),
 250              k->package() != nullptr ? k->package()->name()->as_C_string() : "unnamed",
 251              k->module()->loader_data()->loader_name_and_id(),
 252              this->external_name(),
 253              this->package() != nullptr ? this->package()->name()->as_C_string() : "unnamed",
 254              this->module()->loader_data()->loader_name_and_id());
 255     log_trace(class, sealed)(" - %s", ss.as_string());
 256     return false;
 257   }
 258 
 259   for (int i = 0; i < _permitted_subclasses->length(); i++) {
 260     int cp_index = _permitted_subclasses->at(i);
 261     Symbol* name = _constants->klass_name_at(cp_index);
 262     if (name == k->name()) {
 263       log_trace(class, sealed)("- Found it at permitted_subclasses[%d] => cp[%d]", i, cp_index);
 264       return true;
 265     }
 266   }
 267 
 268   ss.print("Failed listed permitted subclass check: class %s is not a permitted subclass of %s",
 269            k->external_name(), this->external_name());
 270   log_trace(class, sealed)(" - %s", ss.as_string());
 271   return false;
 272 }
 273 
 274 // Return nest-host class, resolving, validating and saving it if needed.
 275 // In cases where this is called from a thread that cannot do classloading
 276 // (such as a native JIT thread) then we simply return null, which in turn
 277 // causes the access check to return false. Such code will retry the access
 278 // from a more suitable environment later. Otherwise the _nest_host is always
 279 // set once this method returns.
 280 // Any errors from nest-host resolution must be preserved so they can be queried
 281 // from higher-level access checking code, and reported as part of access checking
 282 // exceptions.
 283 // VirtualMachineErrors are propagated with a null return.
 284 // Under any conditions where the _nest_host can be set to non-null the resulting
 285 // value of it and, if applicable, the nest host resolution/validation error,
 286 // are idempotent.
 287 InstanceKlass* InstanceKlass::nest_host(TRAPS) {
 288   InstanceKlass* nest_host_k = _nest_host;
 289   if (nest_host_k != nullptr) {
 290     return nest_host_k;
 291   }
 292 
 293   ResourceMark rm(THREAD);
 294 
 295   // need to resolve and save our nest-host class.
 296   if (_nest_host_index != 0) { // we have a real nest_host
 297     // Before trying to resolve check if we're in a suitable context
 298     bool can_resolve = THREAD->can_call_java();
 299     if (!can_resolve && !_constants->tag_at(_nest_host_index).is_klass()) {
 300       log_trace(class, nestmates)("Rejected resolution of nest-host of %s in unsuitable thread",
 301                                   this->external_name());
 302       return nullptr; // sentinel to say "try again from a different context"
 303     }
 304 
 305     log_trace(class, nestmates)("Resolving nest-host of %s using cp entry for %s",
 306                                 this->external_name(),
 307                                 _constants->klass_name_at(_nest_host_index)->as_C_string());
 308 
 309     Klass* k = _constants->klass_at(_nest_host_index, THREAD);
 310     if (HAS_PENDING_EXCEPTION) {
 311       if (PENDING_EXCEPTION->is_a(vmClasses::VirtualMachineError_klass())) {
 312         return nullptr; // propagate VMEs
 313       }
 314       stringStream ss;
 315       char* target_host_class = _constants->klass_name_at(_nest_host_index)->as_C_string();
 316       ss.print("Nest host resolution of %s with host %s failed: ",
 317                this->external_name(), target_host_class);
 318       java_lang_Throwable::print(PENDING_EXCEPTION, &ss);
 319       constantPoolHandle cph(THREAD, constants());
 320       SystemDictionary::add_nest_host_error(cph, _nest_host_index, ss);
 321       CLEAR_PENDING_EXCEPTION;
 322 
 323       log_trace(class, nestmates)("%s", ss.base());
 324     } else {
 325       // A valid nest-host is an instance class in the current package that lists this
 326       // class as a nest member. If any of these conditions are not met the class is
 327       // its own nest-host.
 328       const char* error = nullptr;
 329 
 330       // JVMS 5.4.4 indicates package check comes first
 331       if (is_same_class_package(k)) {
 332         // Now check actual membership. We can't be a member if our "host" is
 333         // not an instance class.
 334         if (k->is_instance_klass()) {
 335           nest_host_k = InstanceKlass::cast(k);
 336           bool is_member = nest_host_k->has_nest_member(THREAD, this);
 337           if (is_member) {
 338             _nest_host = nest_host_k; // save resolved nest-host value
 339 
 340             log_trace(class, nestmates)("Resolved nest-host of %s to %s",
 341                                         this->external_name(), k->external_name());
 342             return nest_host_k;
 343           } else {
 344             error = "current type is not listed as a nest member";
 345           }
 346         } else {
 347           error = "host is not an instance class";
 348         }
 349       } else {
 350         error = "types are in different packages";
 351       }
 352 
 353       // something went wrong, so record what and log it
 354       {
 355         stringStream ss;
 356         ss.print("Type %s (loader: %s) is not a nest member of type %s (loader: %s): %s",
 357                  this->external_name(),
 358                  this->class_loader_data()->loader_name_and_id(),
 359                  k->external_name(),
 360                  k->class_loader_data()->loader_name_and_id(),
 361                  error);
 362         constantPoolHandle cph(THREAD, constants());
 363         SystemDictionary::add_nest_host_error(cph, _nest_host_index, ss);
 364         log_trace(class, nestmates)("%s", ss.base());
 365       }
 366     }
 367   } else {
 368     log_trace(class, nestmates)("Type %s is not part of a nest: setting nest-host to self",
 369                                 this->external_name());
 370   }
 371 
 372   // Either not in an explicit nest, or else an error occurred, so
 373   // the nest-host is set to `this`. Any thread that sees this assignment
 374   // will also see any setting of nest_host_error(), if applicable.
 375   return (_nest_host = this);
 376 }
 377 
 378 // Dynamic nest member support: set this class's nest host to the given class.
 379 // This occurs as part of the class definition, as soon as the instanceKlass
 380 // has been created and doesn't require further resolution. The code:
 381 //    lookup().defineHiddenClass(bytes_for_X, NESTMATE);
 382 // results in:
 383 //    class_of_X.set_nest_host(lookup().lookupClass().getNestHost())
 384 // If it has an explicit _nest_host_index or _nest_members, these will be ignored.
 385 // We also know the "host" is a valid nest-host in the same package so we can
 386 // assert some of those facts.
 387 void InstanceKlass::set_nest_host(InstanceKlass* host) {
 388   assert(is_hidden(), "must be a hidden class");
 389   assert(host != nullptr, "null nest host specified");
 390   assert(_nest_host == nullptr, "current class has resolved nest-host");
 391   assert(nest_host_error() == nullptr, "unexpected nest host resolution error exists: %s",
 392          nest_host_error());
 393   assert((host->_nest_host == nullptr && host->_nest_host_index == 0) ||
 394          (host->_nest_host == host), "proposed host is not a valid nest-host");
 395   // Can't assert this as package is not set yet:
 396   // assert(is_same_class_package(host), "proposed host is in wrong package");
 397 
 398   if (log_is_enabled(Trace, class, nestmates)) {
 399     ResourceMark rm;
 400     const char* msg = "";
 401     // a hidden class does not expect a statically defined nest-host
 402     if (_nest_host_index > 0) {
 403       msg = "(the NestHost attribute in the current class is ignored)";
 404     } else if (_nest_members != nullptr && _nest_members != Universe::the_empty_short_array()) {
 405       msg = "(the NestMembers attribute in the current class is ignored)";
 406     }
 407     log_trace(class, nestmates)("Injected type %s into the nest of %s %s",
 408                                 this->external_name(),
 409                                 host->external_name(),
 410                                 msg);
 411   }
 412   // set dynamic nest host
 413   _nest_host = host;
 414   // Record dependency to keep nest host from being unloaded before this class.
 415   ClassLoaderData* this_key = class_loader_data();
 416   assert(this_key != nullptr, "sanity");
 417   this_key->record_dependency(host);
 418 }
 419 
 420 // check if 'this' and k are nestmates (same nest_host), or k is our nest_host,
 421 // or we are k's nest_host - all of which is covered by comparing the two
 422 // resolved_nest_hosts.
 423 // Any exceptions (i.e. VMEs) are propagated.
 424 bool InstanceKlass::has_nestmate_access_to(InstanceKlass* k, TRAPS) {
 425 
 426   assert(this != k, "this should be handled by higher-level code");
 427 
 428   // Per JVMS 5.4.4 we first resolve and validate the current class, then
 429   // the target class k.
 430 
 431   InstanceKlass* cur_host = nest_host(CHECK_false);
 432   if (cur_host == nullptr) {
 433     return false;
 434   }
 435 
 436   Klass* k_nest_host = k->nest_host(CHECK_false);
 437   if (k_nest_host == nullptr) {
 438     return false;
 439   }
 440 
 441   bool access = (cur_host == k_nest_host);
 442 
 443   ResourceMark rm(THREAD);
 444   log_trace(class, nestmates)("Class %s does %shave nestmate access to %s",
 445                               this->external_name(),
 446                               access ? "" : "NOT ",
 447                               k->external_name());
 448   return access;
 449 }
 450 
 451 const char* InstanceKlass::nest_host_error() {
 452   if (_nest_host_index == 0) {
 453     return nullptr;
 454   } else {
 455     constantPoolHandle cph(Thread::current(), constants());
 456     return SystemDictionary::find_nest_host_error(cph, (int)_nest_host_index);
 457   }
 458 }
 459 
 460 InstanceKlass* InstanceKlass::allocate_instance_klass(const ClassFileParser& parser, TRAPS) {
 461   const int size = InstanceKlass::size(parser.vtable_size(),
 462                                        parser.itable_size(),
 463                                        nonstatic_oop_map_size(parser.total_oop_map_count()),
 464                                        parser.is_interface());
 465 
 466   const Symbol* const class_name = parser.class_name();
 467   assert(class_name != nullptr, "invariant");
 468   ClassLoaderData* loader_data = parser.loader_data();
 469   assert(loader_data != nullptr, "invariant");
 470 
 471   InstanceKlass* ik;
 472 
 473   // Allocation
 474   if (parser.is_instance_ref_klass()) {
 475     // java.lang.ref.Reference
 476     ik = new (loader_data, size, THREAD) InstanceRefKlass(parser);
 477   } else if (class_name == vmSymbols::java_lang_Class()) {
 478     // mirror - java.lang.Class
 479     ik = new (loader_data, size, THREAD) InstanceMirrorKlass(parser);
 480   } else if (is_stack_chunk_class(class_name, loader_data)) {
 481     // stack chunk
 482     ik = new (loader_data, size, THREAD) InstanceStackChunkKlass(parser);
 483   } else if (is_class_loader(class_name, parser)) {
 484     // class loader - java.lang.ClassLoader
 485     ik = new (loader_data, size, THREAD) InstanceClassLoaderKlass(parser);
 486   } else {
 487     // normal
 488     ik = new (loader_data, size, THREAD) InstanceKlass(parser);
 489   }
 490 
 491   if (ik != nullptr && UseCompressedClassPointers) {
 492     assert(CompressedKlassPointers::is_encodable(ik),
 493            "Klass " PTR_FORMAT "needs a narrow Klass ID, but is not encodable", p2i(ik));
 494   }
 495 
 496   // Check for pending exception before adding to the loader data and incrementing
 497   // class count.  Can get OOM here.
 498   if (HAS_PENDING_EXCEPTION) {
 499     return nullptr;
 500   }
 501 
 502   return ik;
 503 }
 504 
 505 
 506 // copy method ordering from resource area to Metaspace
 507 void InstanceKlass::copy_method_ordering(const intArray* m, TRAPS) {
 508   if (m != nullptr) {
 509     // allocate a new array and copy contents (memcpy?)
 510     _method_ordering = MetadataFactory::new_array<int>(class_loader_data(), m->length(), CHECK);
 511     for (int i = 0; i < m->length(); i++) {
 512       _method_ordering->at_put(i, m->at(i));
 513     }
 514   } else {
 515     _method_ordering = Universe::the_empty_int_array();
 516   }
 517 }
 518 
 519 // create a new array of vtable_indices for default methods
 520 Array<int>* InstanceKlass::create_new_default_vtable_indices(int len, TRAPS) {
 521   Array<int>* vtable_indices = MetadataFactory::new_array<int>(class_loader_data(), len, CHECK_NULL);
 522   assert(default_vtable_indices() == nullptr, "only create once");
 523   set_default_vtable_indices(vtable_indices);
 524   return vtable_indices;
 525 }
 526 
 527 
 528 InstanceKlass::InstanceKlass() {
 529   assert(CDSConfig::is_dumping_static_archive() || CDSConfig::is_using_archive(), "only for CDS");
 530 }
 531 
 532 InstanceKlass::InstanceKlass(const ClassFileParser& parser, KlassKind kind, ReferenceType reference_type) :
 533   Klass(kind),
 534   _nest_members(nullptr),
 535   _nest_host(nullptr),
 536   _permitted_subclasses(nullptr),
 537   _record_components(nullptr),
 538   _static_field_size(parser.static_field_size()),
 539   _nonstatic_oop_map_size(nonstatic_oop_map_size(parser.total_oop_map_count())),
 540   _itable_len(parser.itable_size()),
 541   _nest_host_index(0),
 542   _init_state(allocated),
 543   _reference_type(reference_type),
 544   _init_thread(nullptr)
 545 {
 546   set_vtable_length(parser.vtable_size());
 547   set_access_flags(parser.access_flags());
 548   if (parser.is_hidden()) set_is_hidden();
 549   set_layout_helper(Klass::instance_layout_helper(parser.layout_size(),
 550                                                     false));
 551 
 552   assert(nullptr == _methods, "underlying memory not zeroed?");
 553   assert(is_instance_klass(), "is layout incorrect?");
 554   assert(size_helper() == parser.layout_size(), "incorrect size_helper?");
 555 }
 556 
 557 void InstanceKlass::set_is_cloneable() {
 558   if (name() == vmSymbols::java_lang_invoke_MemberName()) {
 559     assert(is_final(), "no subclasses allowed");
 560     // MemberName cloning should not be intrinsified and always happen in JVM_Clone.
 561   } else if (reference_type() != REF_NONE) {
 562     // Reference cloning should not be intrinsified and always happen in JVM_Clone.
 563   } else {
 564     set_is_cloneable_fast();
 565   }
 566 }
 567 
 568 void InstanceKlass::deallocate_methods(ClassLoaderData* loader_data,
 569                                        Array<Method*>* methods) {
 570   if (methods != nullptr && methods != Universe::the_empty_method_array() &&
 571       !methods->in_aot_cache()) {
 572     for (int i = 0; i < methods->length(); i++) {
 573       Method* method = methods->at(i);
 574       if (method == nullptr) continue;  // maybe null if error processing
 575       // Only want to delete methods that are not executing for RedefineClasses.
 576       // The previous version will point to them so they're not totally dangling
 577       assert (!method->on_stack(), "shouldn't be called with methods on stack");
 578       MetadataFactory::free_metadata(loader_data, method);
 579     }
 580     MetadataFactory::free_array<Method*>(loader_data, methods);
 581   }
 582 }
 583 
 584 void InstanceKlass::deallocate_interfaces(ClassLoaderData* loader_data,
 585                                           const InstanceKlass* super_klass,
 586                                           Array<InstanceKlass*>* local_interfaces,
 587                                           Array<InstanceKlass*>* transitive_interfaces) {
 588   // Only deallocate transitive interfaces if not empty, same as super class
 589   // or same as local interfaces.  See code in parseClassFile.
 590   Array<InstanceKlass*>* ti = transitive_interfaces;
 591   if (ti != Universe::the_empty_instance_klass_array() && ti != local_interfaces) {
 592     // check that the interfaces don't come from super class
 593     Array<InstanceKlass*>* sti = (super_klass == nullptr) ? nullptr :
 594                     super_klass->transitive_interfaces();
 595     if (ti != sti && ti != nullptr && !ti->in_aot_cache()) {
 596       MetadataFactory::free_array<InstanceKlass*>(loader_data, ti);
 597     }
 598   }
 599 
 600   // local interfaces can be empty
 601   if (local_interfaces != Universe::the_empty_instance_klass_array() &&
 602       local_interfaces != nullptr && !local_interfaces->in_aot_cache()) {
 603     MetadataFactory::free_array<InstanceKlass*>(loader_data, local_interfaces);
 604   }
 605 }
 606 
 607 void InstanceKlass::deallocate_record_components(ClassLoaderData* loader_data,
 608                                                  Array<RecordComponent*>* record_components) {
 609   if (record_components != nullptr && !record_components->in_aot_cache()) {
 610     for (int i = 0; i < record_components->length(); i++) {
 611       RecordComponent* record_component = record_components->at(i);
 612       MetadataFactory::free_metadata(loader_data, record_component);
 613     }
 614     MetadataFactory::free_array<RecordComponent*>(loader_data, record_components);
 615   }
 616 }
 617 
 618 // This function deallocates the metadata and C heap pointers that the
 619 // InstanceKlass points to.
 620 void InstanceKlass::deallocate_contents(ClassLoaderData* loader_data) {
 621   // Orphan the mirror first, CMS thinks it's still live.
 622   if (java_mirror() != nullptr) {
 623     java_lang_Class::set_klass(java_mirror(), nullptr);
 624   }
 625 
 626   // Also remove mirror from handles
 627   loader_data->remove_handle(_java_mirror);
 628 
 629   // Need to take this class off the class loader data list.
 630   loader_data->remove_class(this);
 631 
 632   // The array_klass for this class is created later, after error handling.
 633   // For class redefinition, we keep the original class so this scratch class
 634   // doesn't have an array class.  Either way, assert that there is nothing
 635   // to deallocate.
 636   assert(array_klasses() == nullptr, "array classes shouldn't be created for this class yet");
 637 
 638   // Release C heap allocated data that this points to, which includes
 639   // reference counting symbol names.
 640   // Can't release the constant pool or MethodData C heap data here because the constant
 641   // pool can be deallocated separately from the InstanceKlass for default methods and
 642   // redefine classes.  MethodData can also be released separately.
 643   release_C_heap_structures(/* release_sub_metadata */ false);
 644 
 645   deallocate_methods(loader_data, methods());
 646   set_methods(nullptr);
 647 
 648   deallocate_record_components(loader_data, record_components());
 649   set_record_components(nullptr);
 650 
 651   if (method_ordering() != nullptr &&
 652       method_ordering() != Universe::the_empty_int_array() &&
 653       !method_ordering()->in_aot_cache()) {
 654     MetadataFactory::free_array<int>(loader_data, method_ordering());
 655   }
 656   set_method_ordering(nullptr);
 657 
 658   // default methods can be empty
 659   if (default_methods() != nullptr &&
 660       default_methods() != Universe::the_empty_method_array() &&
 661       !default_methods()->in_aot_cache()) {
 662     MetadataFactory::free_array<Method*>(loader_data, default_methods());
 663   }
 664   // Do NOT deallocate the default methods, they are owned by superinterfaces.
 665   set_default_methods(nullptr);
 666 
 667   // default methods vtable indices can be empty
 668   if (default_vtable_indices() != nullptr &&
 669       !default_vtable_indices()->in_aot_cache()) {
 670     MetadataFactory::free_array<int>(loader_data, default_vtable_indices());
 671   }
 672   set_default_vtable_indices(nullptr);
 673 
 674 
 675   // This array is in Klass, but remove it with the InstanceKlass since
 676   // this place would be the only caller and it can share memory with transitive
 677   // interfaces.
 678   if (secondary_supers() != nullptr &&
 679       secondary_supers() != Universe::the_empty_klass_array() &&
 680       // see comments in compute_secondary_supers about the following cast
 681       (address)(secondary_supers()) != (address)(transitive_interfaces()) &&
 682       !secondary_supers()->in_aot_cache()) {
 683     MetadataFactory::free_array<Klass*>(loader_data, secondary_supers());
 684   }
 685   set_secondary_supers(nullptr, SECONDARY_SUPERS_BITMAP_EMPTY);
 686 
 687   deallocate_interfaces(loader_data, super(), local_interfaces(), transitive_interfaces());
 688   set_transitive_interfaces(nullptr);
 689   set_local_interfaces(nullptr);
 690 
 691   if (fieldinfo_stream() != nullptr && !fieldinfo_stream()->in_aot_cache()) {
 692     MetadataFactory::free_array<u1>(loader_data, fieldinfo_stream());
 693   }
 694   set_fieldinfo_stream(nullptr);
 695 
 696   if (fieldinfo_search_table() != nullptr && !fieldinfo_search_table()->in_aot_cache()) {
 697     MetadataFactory::free_array<u1>(loader_data, fieldinfo_search_table());
 698   }
 699   set_fieldinfo_search_table(nullptr);
 700 
 701   if (fields_status() != nullptr && !fields_status()->in_aot_cache()) {
 702     MetadataFactory::free_array<FieldStatus>(loader_data, fields_status());
 703   }
 704   set_fields_status(nullptr);
 705 
 706   // If a method from a redefined class is using this constant pool, don't
 707   // delete it, yet.  The new class's previous version will point to this.
 708   if (constants() != nullptr) {
 709     assert (!constants()->on_stack(), "shouldn't be called if anything is onstack");
 710     if (!constants()->in_aot_cache()) {
 711       MetadataFactory::free_metadata(loader_data, constants());
 712     }
 713     // Delete any cached resolution errors for the constant pool
 714     SystemDictionary::delete_resolution_error(constants());
 715 
 716     set_constants(nullptr);
 717   }
 718 
 719   if (inner_classes() != nullptr &&
 720       inner_classes() != Universe::the_empty_short_array() &&
 721       !inner_classes()->in_aot_cache()) {
 722     MetadataFactory::free_array<jushort>(loader_data, inner_classes());
 723   }
 724   set_inner_classes(nullptr);
 725 
 726   if (nest_members() != nullptr &&
 727       nest_members() != Universe::the_empty_short_array() &&
 728       !nest_members()->in_aot_cache()) {
 729     MetadataFactory::free_array<jushort>(loader_data, nest_members());
 730   }
 731   set_nest_members(nullptr);
 732 
 733   if (permitted_subclasses() != nullptr &&
 734       permitted_subclasses() != Universe::the_empty_short_array() &&
 735       !permitted_subclasses()->in_aot_cache()) {
 736     MetadataFactory::free_array<jushort>(loader_data, permitted_subclasses());
 737   }
 738   set_permitted_subclasses(nullptr);
 739 
 740   // We should deallocate the Annotations instance if it's not in shared spaces.
 741   if (annotations() != nullptr && !annotations()->in_aot_cache()) {
 742     MetadataFactory::free_metadata(loader_data, annotations());
 743   }
 744   set_annotations(nullptr);
 745 
 746   SystemDictionaryShared::handle_class_unloading(this);
 747 
 748 #if INCLUDE_CDS_JAVA_HEAP
 749   if (CDSConfig::is_dumping_heap()) {
 750     HeapShared::remove_scratch_objects(this);
 751   }
 752 #endif
 753 }
 754 
 755 bool InstanceKlass::is_record() const {
 756   return _record_components != nullptr &&
 757          is_final() &&
 758          super() == vmClasses::Record_klass();
 759 }
 760 
 761 bool InstanceKlass::is_sealed() const {
 762   return _permitted_subclasses != nullptr &&
 763          _permitted_subclasses != Universe::the_empty_short_array();
 764 }
 765 
 766 // JLS 8.9: An enum class is either implicitly final and derives
 767 // from java.lang.Enum, or else is implicitly sealed to its
 768 // anonymous subclasses. This query detects both kinds.
 769 // It does not validate the finality or
 770 // sealing conditions: it merely checks for a super of Enum.
 771 // This is sufficient for recognizing well-formed enums.
 772 bool InstanceKlass::is_enum_subclass() const {
 773   InstanceKlass* s = super();
 774   return (s == vmClasses::Enum_klass() ||
 775           (s != nullptr && s->super() == vmClasses::Enum_klass()));
 776 }
 777 
 778 bool InstanceKlass::should_be_initialized() const {
 779   return !is_initialized();
 780 }
 781 
 782 klassItable InstanceKlass::itable() const {
 783   return klassItable(const_cast<InstanceKlass*>(this));
 784 }
 785 
 786 // JVMTI spec thinks there are signers and protection domain in the
 787 // instanceKlass.  These accessors pretend these fields are there.
 788 // The hprof specification also thinks these fields are in InstanceKlass.
 789 oop InstanceKlass::protection_domain() const {
 790   // return the protection_domain from the mirror
 791   return java_lang_Class::protection_domain(java_mirror());
 792 }
 793 
 794 objArrayOop InstanceKlass::signers() const {
 795   // return the signers from the mirror
 796   return java_lang_Class::signers(java_mirror());
 797 }
 798 
 799 oop InstanceKlass::init_lock() const {
 800   // return the init lock from the mirror
 801   oop lock = java_lang_Class::init_lock(java_mirror());
 802   // Prevent reordering with any access of initialization state
 803   OrderAccess::loadload();
 804   assert(lock != nullptr || !is_not_initialized(), // initialized or in_error state
 805          "only fully initialized state can have a null lock");
 806   return lock;
 807 }
 808 
 809 // Set the initialization lock to null so the object can be GC'ed. Any racing
 810 // threads to get this lock will see a null lock and will not lock.
 811 // That's okay because they all check for initialized state after getting
 812 // the lock and return. For preempted vthreads we keep the oop protected
 813 // in the ObjectMonitor (see ObjectMonitor::set_object_strong()).
 814 void InstanceKlass::fence_and_clear_init_lock() {
 815   // make sure previous stores are all done, notably the init_state.
 816   OrderAccess::storestore();
 817   java_lang_Class::clear_init_lock(java_mirror());
 818   assert(!is_not_initialized(), "class must be initialized now");
 819 }
 820 
 821 class PreemptableInitCall {
 822   JavaThread* _thread;
 823   bool _previous;
 824   DEBUG_ONLY(InstanceKlass* _previous_klass;)
 825  public:
 826   PreemptableInitCall(JavaThread* thread, InstanceKlass* ik) : _thread(thread) {
 827     _previous = thread->at_preemptable_init();
 828     _thread->set_at_preemptable_init(true);
 829     DEBUG_ONLY(_previous_klass = _thread->preempt_init_klass();)
 830     DEBUG_ONLY(_thread->set_preempt_init_klass(ik));
 831   }
 832   ~PreemptableInitCall() {
 833     _thread->set_at_preemptable_init(_previous);
 834     DEBUG_ONLY(_thread->set_preempt_init_klass(_previous_klass));
 835   }
 836 };
 837 
 838 void InstanceKlass::initialize_preemptable(TRAPS) {
 839   if (this->should_be_initialized()) {
 840     PreemptableInitCall pic(THREAD, this);
 841     initialize_impl(THREAD);
 842   } else {
 843     assert(is_initialized(), "sanity check");
 844   }
 845 }
 846 
 847 // See "The Virtual Machine Specification" section 2.16.5 for a detailed explanation of the class initialization
 848 // process. The step comments refers to the procedure described in that section.
 849 // Note: implementation moved to static method to expose the this pointer.
 850 void InstanceKlass::initialize(TRAPS) {
 851   if (this->should_be_initialized()) {
 852     initialize_impl(CHECK);
 853     // Note: at this point the class may be initialized
 854     //       OR it may be in the state of being initialized
 855     //       in case of recursive initialization!
 856   } else {
 857     assert(is_initialized(), "sanity check");
 858   }
 859 }
 860 
 861 #ifdef ASSERT
 862 void InstanceKlass::assert_no_clinit_will_run_for_aot_initialized_class() const {
 863   assert(has_aot_initialized_mirror(), "must be");
 864 
 865   InstanceKlass* s = super();
 866   if (s != nullptr) {
 867     DEBUG_ONLY(ResourceMark rm);
 868     assert(s->is_initialized(), "super class %s of aot-inited class %s must have been initialized",
 869            s->external_name(), external_name());
 870     s->assert_no_clinit_will_run_for_aot_initialized_class();
 871   }
 872 
 873   Array<InstanceKlass*>* interfaces = local_interfaces();
 874   int len = interfaces->length();
 875   for (int i = 0; i < len; i++) {
 876     InstanceKlass* intf = interfaces->at(i);
 877     if (!intf->is_initialized()) {
 878       ResourceMark rm;
 879       // Note: an interface needs to be marked as is_initialized() only if
 880       // - it has a <clinit>
 881       // - it has declared a default method.
 882       assert(!intf->interface_needs_clinit_execution_as_super(/*also_check_supers*/false),
 883              "uninitialized super interface %s of aot-inited class %s must not have <clinit>",
 884              intf->external_name(), external_name());
 885     }
 886   }
 887 }
 888 #endif
 889 
 890 #if INCLUDE_CDS
 891 // early_init -- we are moving this class into the fully_initialized state before the
 892 // JVM is able to execute any bytecodes. See AOTLinkedClassBulkLoader::is_initializing_classes_early().
 893 void InstanceKlass::initialize_with_aot_initialized_mirror(bool early_init, TRAPS) {
 894   assert(has_aot_initialized_mirror(), "must be");
 895   assert(CDSConfig::is_loading_heap(), "must be");
 896   assert(CDSConfig::is_using_aot_linked_classes(), "must be");
 897   assert_no_clinit_will_run_for_aot_initialized_class();
 898 
 899   if (is_initialized()) {
 900     return;
 901   }
 902 
 903   if (log_is_enabled(Info, aot, init)) {
 904     ResourceMark rm;
 905     log_info(aot, init)("%s (aot-inited%s)", external_name(), early_init ? ", early" : "");
 906   }
 907 
 908   if (is_runtime_setup_required()) {
 909     assert(!early_init, "must not call");
 910     // Need to take the slow path, which will call the runtimeSetup() function instead
 911     // of <clinit>
 912     initialize(CHECK);
 913     return;
 914   }
 915 
 916   LogTarget(Info, class, init) lt;
 917   if (lt.is_enabled()) {
 918     ResourceMark rm(THREAD);
 919     LogStream ls(lt);
 920     ls.print("%d Initializing ", call_class_initializer_counter++);
 921     name()->print_value_on(&ls);
 922     ls.print_cr("(aot-inited) (" PTR_FORMAT ") by thread \"%s\"",
 923                 p2i(this), THREAD->name());
 924   }
 925 
 926   if (early_init) {
 927     precond(AOTLinkedClassBulkLoader::is_initializing_classes_early());
 928     precond(is_linked());
 929     precond(init_thread() == nullptr);
 930     set_init_state(fully_initialized);
 931     fence_and_clear_init_lock();
 932     return;
 933   }
 934 
 935   link_class(CHECK);
 936 
 937 #ifdef ASSERT
 938   {
 939     Handle h_init_lock(THREAD, init_lock());
 940     ObjectLocker ol(h_init_lock, THREAD);
 941     assert(!is_initialized(), "sanity");
 942     assert(!is_being_initialized(), "sanity");
 943     assert(!is_in_error_state(), "sanity");
 944   }
 945 #endif
 946 
 947   set_init_thread(THREAD);
 948   set_initialization_state_and_notify(fully_initialized, CHECK);
 949 }
 950 #endif
 951 
 952 bool InstanceKlass::verify_code(TRAPS) {
 953   // 1) Verify the bytecodes
 954   return Verifier::verify(this, should_verify_class(), THREAD);
 955 }
 956 
 957 void InstanceKlass::link_class(TRAPS) {
 958   assert(is_loaded(), "must be loaded");
 959   if (!is_linked()) {
 960     link_class_impl(CHECK);
 961   }
 962 }
 963 
 964 // Called to verify that a class can link during initialization, without
 965 // throwing a VerifyError.
 966 bool InstanceKlass::link_class_or_fail(TRAPS) {
 967   assert(is_loaded(), "must be loaded");
 968   if (!is_linked()) {
 969     link_class_impl(CHECK_false);
 970   }
 971   return is_linked();
 972 }
 973 
 974 bool InstanceKlass::link_class_impl(TRAPS) {
 975   if (CDSConfig::is_dumping_static_archive() && SystemDictionaryShared::has_class_failed_verification(this)) {
 976     // This is for CDS static dump only -- we use the in_error_state to indicate that
 977     // the class has failed verification. Throwing the NoClassDefFoundError here is just
 978     // a convenient way to stop repeat attempts to verify the same (bad) class.
 979     //
 980     // Note that the NoClassDefFoundError is not part of the JLS, and should not be thrown
 981     // if we are executing Java code. This is not a problem for CDS dumping phase since
 982     // it doesn't execute any Java code.
 983     ResourceMark rm(THREAD);
 984     // Names are all known to be < 64k so we know this formatted message is not excessively large.
 985     Exceptions::fthrow(THREAD_AND_LOCATION,
 986                        vmSymbols::java_lang_NoClassDefFoundError(),
 987                        "Class %s, or one of its supertypes, failed class initialization",
 988                        external_name());
 989     return false;
 990   }
 991   // return if already verified
 992   if (is_linked()) {
 993     return true;
 994   }
 995 
 996   // Timing
 997   // timer handles recursion
 998   JavaThread* jt = THREAD;
 999 
1000   // link super class before linking this class
1001   InstanceKlass* super_klass = super();
1002   if (super_klass != nullptr) {
1003     if (super_klass->is_interface()) {  // check if super class is an interface
1004       ResourceMark rm(THREAD);
1005       // Names are all known to be < 64k so we know this formatted message is not excessively large.
1006       Exceptions::fthrow(
1007         THREAD_AND_LOCATION,
1008         vmSymbols::java_lang_IncompatibleClassChangeError(),
1009         "class %s has interface %s as super class",
1010         external_name(),
1011         super_klass->external_name()
1012       );
1013       return false;
1014     }
1015 
1016     super_klass->link_class_impl(CHECK_false);
1017   }
1018 
1019   // link all interfaces implemented by this class before linking this class
1020   Array<InstanceKlass*>* interfaces = local_interfaces();
1021   int num_interfaces = interfaces->length();
1022   for (int index = 0; index < num_interfaces; index++) {
1023     InstanceKlass* interk = interfaces->at(index);
1024     interk->link_class_impl(CHECK_false);
1025   }
1026 
1027   // in case the class is linked in the process of linking its superclasses
1028   if (is_linked()) {
1029     return true;
1030   }
1031 
1032   // trace only the link time for this klass that includes
1033   // the verification time
1034   PerfClassTraceTime vmtimer(ClassLoader::perf_class_link_time(),
1035                              ClassLoader::perf_class_link_selftime(),
1036                              ClassLoader::perf_classes_linked(),
1037                              jt->get_thread_stat()->perf_recursion_counts_addr(),
1038                              jt->get_thread_stat()->perf_timers_addr(),
1039                              PerfClassTraceTime::CLASS_LINK);
1040 
1041   // verification & rewriting
1042   {
1043     HandleMark hm(THREAD);
1044     Handle h_init_lock(THREAD, init_lock());
1045     ObjectLocker ol(h_init_lock, CHECK_PREEMPTABLE_false);
1046     // Don't allow preemption if we link/initialize classes below,
1047     // since that would release this monitor while we are in the
1048     // middle of linking this class.
1049     NoPreemptMark npm(THREAD);
1050 
1051     // rewritten will have been set if loader constraint error found
1052     // on an earlier link attempt
1053     // don't verify or rewrite if already rewritten
1054     //
1055 
1056     if (!is_linked()) {
1057       if (!is_rewritten()) {
1058         if (in_aot_cache()) {
1059           assert(!verified_at_dump_time(), "must be");
1060         }
1061         {
1062           bool verify_ok = verify_code(THREAD);
1063           if (!verify_ok) {
1064             return false;
1065           }
1066         }
1067 
1068         // Just in case a side-effect of verify linked this class already
1069         // (which can sometimes happen since the verifier loads classes
1070         // using custom class loaders, which are free to initialize things)
1071         if (is_linked()) {
1072           return true;
1073         }
1074 
1075         // also sets rewritten
1076         rewrite_class(CHECK_false);
1077       } else if (in_aot_cache()) {
1078         SystemDictionaryShared::check_verification_constraints(this, CHECK_false);
1079       }
1080 
1081       // relocate jsrs and link methods after they are all rewritten
1082       link_methods(CHECK_false);
1083 
1084       // Initialize the vtable and interface table after
1085       // methods have been rewritten since rewrite may
1086       // fabricate new Method*s.
1087       // also does loader constraint checking
1088       //
1089       // initialize_vtable and initialize_itable need to be rerun
1090       // for a shared class if
1091       // 1) the class is loaded by custom class loader or
1092       // 2) the class is loaded by built-in class loader but failed to add archived loader constraints or
1093       // 3) the class was not verified during dump time
1094       bool need_init_table = true;
1095       if (in_aot_cache() && verified_at_dump_time() &&
1096           SystemDictionaryShared::check_linking_constraints(THREAD, this)) {
1097         need_init_table = false;
1098       }
1099       if (need_init_table) {
1100         vtable().initialize_vtable_and_check_constraints(CHECK_false);
1101         itable().initialize_itable_and_check_constraints(CHECK_false);
1102       }
1103 #ifdef ASSERT
1104       vtable().verify(tty, true);
1105       // In case itable verification is ever added.
1106       // itable().verify(tty, true);
1107 #endif
1108       if (Universe::is_fully_initialized()) {
1109         DeoptimizationScope deopt_scope;
1110         {
1111           // Now mark all code that assumes the class is not linked.
1112           // Set state under the Compile_lock also.
1113           MutexLocker ml(THREAD, Compile_lock);
1114 
1115           set_init_state(linked);
1116           CodeCache::mark_dependents_on(&deopt_scope, this);
1117         }
1118         // Perform the deopt handshake outside Compile_lock.
1119         deopt_scope.deoptimize_marked();
1120       } else {
1121         set_init_state(linked);
1122       }
1123       if (JvmtiExport::should_post_class_prepare()) {
1124         JvmtiExport::post_class_prepare(THREAD, this);
1125       }
1126     }
1127   }
1128   return true;
1129 }
1130 
1131 // Rewrite the byte codes of all of the methods of a class.
1132 // The rewriter must be called exactly once. Rewriting must happen after
1133 // verification but before the first method of the class is executed.
1134 void InstanceKlass::rewrite_class(TRAPS) {
1135   assert(is_loaded(), "must be loaded");
1136   if (is_rewritten()) {
1137     assert(in_aot_cache(), "rewriting an unshared class?");
1138     return;
1139   }
1140   Rewriter::rewrite(this, CHECK);
1141   set_rewritten();
1142 }
1143 
1144 // Now relocate and link method entry points after class is rewritten.
1145 // This is outside is_rewritten flag. In case of an exception, it can be
1146 // executed more than once.
1147 void InstanceKlass::link_methods(TRAPS) {
1148   PerfTraceElapsedTime timer(ClassLoader::perf_ik_link_methods_time());
1149 
1150   int len = methods()->length();
1151   for (int i = len-1; i >= 0; i--) {
1152     methodHandle m(THREAD, methods()->at(i));
1153     RuntimeUpcalls::install_upcalls(m);
1154 
1155     // Set up method entry points for compiler and interpreter    .
1156     m->link_method(m, CHECK);
1157   }
1158 }
1159 
1160 // Eagerly initialize superinterfaces that declare default methods (concrete instance: any access)
1161 void InstanceKlass::initialize_super_interfaces(TRAPS) {
1162   assert (has_nonstatic_concrete_methods(), "caller should have checked this");
1163   for (int i = 0; i < local_interfaces()->length(); ++i) {
1164     InstanceKlass* ik = local_interfaces()->at(i);
1165 
1166     // Initialization is depth first search ie. we start with top of the inheritance tree
1167     // has_nonstatic_concrete_methods drives searching superinterfaces since it
1168     // means has_nonstatic_concrete_methods in its superinterface hierarchy
1169     if (ik->has_nonstatic_concrete_methods()) {
1170       ik->initialize_super_interfaces(CHECK);
1171     }
1172 
1173     // Only initialize() interfaces that "declare" concrete methods.
1174     if (ik->should_be_initialized() && ik->declares_nonstatic_concrete_methods()) {
1175       ik->initialize(CHECK);
1176     }
1177   }
1178 }
1179 
1180 using InitializationErrorTable = HashTable<const InstanceKlass*, OopHandle, 107, AnyObj::C_HEAP, mtClass>;
1181 static InitializationErrorTable* _initialization_error_table;
1182 
1183 void InstanceKlass::add_initialization_error(JavaThread* current, Handle exception) {
1184   // Create the same exception with a message indicating the thread name,
1185   // and the StackTraceElements.
1186   Handle init_error = java_lang_Throwable::create_initialization_error(current, exception);
1187   ResourceMark rm(current);
1188   if (init_error.is_null()) {
1189     log_trace(class, init)("Unable to create the desired initialization error for class %s", external_name());
1190 
1191     // We failed to create the new exception, most likely due to either out-of-memory or
1192     // a stackoverflow error. If the original exception was either of those then we save
1193     // the shared, pre-allocated, stackless, instance of that exception.
1194     if (exception->klass() == vmClasses::StackOverflowError_klass()) {
1195       log_debug(class, init)("Using shared StackOverflowError as initialization error for class %s", external_name());
1196       init_error = Handle(current, Universe::class_init_stack_overflow_error());
1197     } else if (exception->klass() == vmClasses::OutOfMemoryError_klass()) {
1198       log_debug(class, init)("Using shared OutOfMemoryError as initialization error for class %s", external_name());
1199       init_error = Handle(current, Universe::class_init_out_of_memory_error());
1200     } else {
1201       return;
1202     }
1203   }
1204 
1205   MutexLocker ml(current, ClassInitError_lock);
1206   OopHandle elem = OopHandle(Universe::vm_global(), init_error());
1207   bool created;
1208   if (_initialization_error_table == nullptr) {
1209     _initialization_error_table = new (mtClass) InitializationErrorTable();
1210   }
1211   _initialization_error_table->put_if_absent(this, elem, &created);
1212   assert(created, "Initialization is single threaded");
1213   log_trace(class, init)("Initialization error added for class %s", external_name());
1214 }
1215 
1216 oop InstanceKlass::get_initialization_error(JavaThread* current) {
1217   MutexLocker ml(current, ClassInitError_lock);
1218   if (_initialization_error_table == nullptr) {
1219     return nullptr;
1220   }
1221   OopHandle* h = _initialization_error_table->get(this);
1222   return (h != nullptr) ? h->resolve() : nullptr;
1223 }
1224 
1225 // Need to remove entries for unloaded classes.
1226 void InstanceKlass::clean_initialization_error_table() {
1227   struct InitErrorTableCleaner {
1228     bool do_entry(const InstanceKlass* ik, OopHandle h) {
1229       if (!ik->is_loader_alive()) {
1230         h.release(Universe::vm_global());
1231         return true;
1232       } else {
1233         return false;
1234       }
1235     }
1236   };
1237 
1238   assert_locked_or_safepoint(ClassInitError_lock);
1239   InitErrorTableCleaner cleaner;
1240   if (_initialization_error_table != nullptr) {
1241     _initialization_error_table->unlink(&cleaner);
1242   }
1243 }
1244 
1245 class ThreadWaitingForClassInit : public StackObj {
1246   JavaThread* _thread;
1247  public:
1248   ThreadWaitingForClassInit(JavaThread* thread, InstanceKlass* ik) : _thread(thread) {
1249     _thread->set_class_to_be_initialized(ik);
1250   }
1251   ~ThreadWaitingForClassInit() {
1252     _thread->set_class_to_be_initialized(nullptr);
1253   }
1254 };
1255 
1256 void InstanceKlass::initialize_impl(TRAPS) {
1257   HandleMark hm(THREAD);
1258 
1259   // Make sure klass is linked (verified) before initialization
1260   // A class could already be verified, since it has been reflected upon.
1261   link_class(CHECK);
1262 
1263   DTRACE_CLASSINIT_PROBE(required, -1);
1264 
1265   bool wait = false;
1266 
1267   JavaThread* jt = THREAD;
1268 
1269   if (ForceProfiling) {
1270     // Preallocate MDOs.
1271     for (int i = 0; i < methods()->length(); i++) {
1272       assert(!HAS_PENDING_EXCEPTION, "");
1273       methodHandle m(THREAD, methods()->at(i));
1274       Method::build_profiling_method_data(m, THREAD);
1275       if (HAS_PENDING_EXCEPTION) {
1276         ResourceMark rm;
1277         log_warning(cds)("MDO preallocation failed for %s", external_name());
1278         CLEAR_PENDING_EXCEPTION;
1279         break;
1280       }
1281     }
1282   }
1283 
1284   bool debug_logging_enabled = log_is_enabled(Debug, class, init);
1285 
1286   // refer to the JVM book page 47 for description of steps
1287   // Step 1
1288   {
1289     Handle h_init_lock(THREAD, init_lock());
1290     ObjectLocker ol(h_init_lock, CHECK_PREEMPTABLE);
1291 
1292     // Step 2
1293     // If we were to use wait() instead of waitInterruptibly() then
1294     // we might end up throwing IE from link/symbol resolution sites
1295     // that aren't expected to throw.  This would wreak havoc.  See 6320309.
1296     while (is_being_initialized() && !is_reentrant_initialization(jt)) {
1297       if (debug_logging_enabled) {
1298         ResourceMark rm(jt);
1299         log_debug(class, init)("Thread \"%s\" waiting for initialization of %s by thread \"%s\"",
1300                                jt->name(), external_name(), init_thread_name());
1301       }
1302       wait = true;
1303       ThreadWaitingForClassInit twcl(THREAD, this);
1304       ol.wait_uninterruptibly(CHECK_PREEMPTABLE);
1305     }
1306 
1307     // Step 3
1308     if (is_being_initialized() && is_reentrant_initialization(jt)) {
1309       if (debug_logging_enabled) {
1310         ResourceMark rm(jt);
1311         log_debug(class, init)("Thread \"%s\" recursively initializing %s",
1312                                jt->name(), external_name());
1313       }
1314       DTRACE_CLASSINIT_PROBE_WAIT(recursive, -1, wait);
1315       return;
1316     }
1317 
1318     // Step 4
1319     if (is_initialized()) {
1320       if (debug_logging_enabled) {
1321         ResourceMark rm(jt);
1322         log_debug(class, init)("Thread \"%s\" found %s already initialized",
1323                                jt->name(), external_name());
1324       }
1325       DTRACE_CLASSINIT_PROBE_WAIT(concurrent, -1, wait);
1326       return;
1327     }
1328 
1329     // Step 5
1330     if (is_in_error_state()) {
1331       if (debug_logging_enabled) {
1332         ResourceMark rm(jt);
1333         log_debug(class, init)("Thread \"%s\" found %s is in error state",
1334                                jt->name(), external_name());
1335       }
1336 
1337       DTRACE_CLASSINIT_PROBE_WAIT(erroneous, -1, wait);
1338       ResourceMark rm(THREAD);
1339       Handle cause(THREAD, get_initialization_error(THREAD));
1340 
1341       stringStream ss;
1342       ss.print("Could not initialize class %s", external_name());
1343       if (cause.is_null()) {
1344         THROW_MSG(vmSymbols::java_lang_NoClassDefFoundError(), ss.as_string());
1345       } else {
1346         THROW_MSG_CAUSE(vmSymbols::java_lang_NoClassDefFoundError(),
1347                         ss.as_string(), cause);
1348       }
1349     } else {
1350 
1351       // Step 6
1352       set_init_state(being_initialized);
1353       set_init_thread(jt);
1354       if (debug_logging_enabled) {
1355         ResourceMark rm(jt);
1356         log_debug(class, init)("Thread \"%s\" is initializing %s",
1357                                jt->name(), external_name());
1358       }
1359     }
1360   }
1361 
1362   // Block preemption once we are the initializer thread. Unmounting now
1363   // would complicate the reentrant case (identity is platform thread).
1364   NoPreemptMark npm(THREAD);
1365 
1366   // Step 7
1367   // Next, if C is a class rather than an interface, initialize it's super class and super
1368   // interfaces.
1369   if (!is_interface()) {
1370     Klass* super_klass = super();
1371     if (super_klass != nullptr && super_klass->should_be_initialized()) {
1372       super_klass->initialize(THREAD);
1373     }
1374     // If C implements any interface that declares a non-static, concrete method,
1375     // the initialization of C triggers initialization of its super interfaces.
1376     // Only need to recurse if has_nonstatic_concrete_methods which includes declaring and
1377     // having a superinterface that declares, non-static, concrete methods
1378     if (!HAS_PENDING_EXCEPTION && has_nonstatic_concrete_methods()) {
1379       initialize_super_interfaces(THREAD);
1380     }
1381 
1382     // If any exceptions, complete abruptly, throwing the same exception as above.
1383     if (HAS_PENDING_EXCEPTION) {
1384       Handle e(THREAD, PENDING_EXCEPTION);
1385       CLEAR_PENDING_EXCEPTION;
1386       {
1387         EXCEPTION_MARK;
1388         add_initialization_error(THREAD, e);
1389         // Locks object, set state, and notify all waiting threads
1390         set_initialization_state_and_notify(initialization_error, THREAD);
1391         CLEAR_PENDING_EXCEPTION;
1392       }
1393       DTRACE_CLASSINIT_PROBE_WAIT(super__failed, -1, wait);
1394       THROW_OOP(e());
1395     }
1396   }
1397 
1398 
1399   // Step 8
1400   {
1401     DTRACE_CLASSINIT_PROBE_WAIT(clinit, -1, wait);
1402     if (class_initializer() != nullptr) {
1403       // Timer includes any side effects of class initialization (resolution,
1404       // etc), but not recursive entry into call_class_initializer().
1405       PerfClassTraceTime timer(ClassLoader::perf_class_init_time(),
1406                                ClassLoader::perf_class_init_selftime(),
1407                                ClassLoader::perf_classes_inited(),
1408                                jt->get_thread_stat()->perf_recursion_counts_addr(),
1409                                jt->get_thread_stat()->perf_timers_addr(),
1410                                PerfClassTraceTime::CLASS_CLINIT);
1411       call_class_initializer(THREAD);
1412     } else {
1413       // The elapsed time is so small it's not worth counting.
1414       if (UsePerfData) {
1415         ClassLoader::perf_classes_inited()->inc();
1416       }
1417       call_class_initializer(THREAD);
1418     }
1419   }
1420 
1421   // Step 9
1422   if (!HAS_PENDING_EXCEPTION) {
1423     set_initialization_state_and_notify(fully_initialized, CHECK);
1424     DEBUG_ONLY(vtable().verify(tty, true);)
1425     CompilationPolicy::replay_training_at_init(this, THREAD);
1426   }
1427   else {
1428     // Step 10 and 11
1429     Handle e(THREAD, PENDING_EXCEPTION);
1430     CLEAR_PENDING_EXCEPTION;
1431     // JVMTI has already reported the pending exception
1432     // JVMTI internal flag reset is needed in order to report ExceptionInInitializerError
1433     JvmtiExport::clear_detected_exception(jt);
1434     {
1435       EXCEPTION_MARK;
1436       add_initialization_error(THREAD, e);
1437       set_initialization_state_and_notify(initialization_error, THREAD);
1438       CLEAR_PENDING_EXCEPTION;   // ignore any exception thrown, class initialization error is thrown below
1439       // JVMTI has already reported the pending exception
1440       // JVMTI internal flag reset is needed in order to report ExceptionInInitializerError
1441       JvmtiExport::clear_detected_exception(jt);
1442     }
1443     DTRACE_CLASSINIT_PROBE_WAIT(error, -1, wait);
1444     if (e->is_a(vmClasses::Error_klass())) {
1445       THROW_OOP(e());
1446     } else {
1447       JavaCallArguments args(e);
1448       THROW_ARG(vmSymbols::java_lang_ExceptionInInitializerError(),
1449                 vmSymbols::throwable_void_signature(),
1450                 &args);
1451     }
1452   }
1453   DTRACE_CLASSINIT_PROBE_WAIT(end, -1, wait);
1454 }
1455 
1456 
1457 void InstanceKlass::set_initialization_state_and_notify(ClassState state, TRAPS) {
1458   Handle h_init_lock(THREAD, init_lock());
1459   if (h_init_lock() != nullptr) {
1460     ObjectLocker ol(h_init_lock, THREAD);
1461     set_init_thread(nullptr); // reset _init_thread before changing _init_state
1462     set_init_state(state);
1463     fence_and_clear_init_lock();
1464     ol.notify_all(CHECK);
1465   } else {
1466     assert(h_init_lock() != nullptr, "The initialization state should never be set twice");
1467     set_init_thread(nullptr); // reset _init_thread before changing _init_state
1468     set_init_state(state);
1469   }
1470 }
1471 
1472 // Update hierarchy. This is done before the new klass has been added to the SystemDictionary. The Compile_lock
1473 // is grabbed, to ensure that the compiler is not using the class hierarchy.
1474 void InstanceKlass::add_to_hierarchy(JavaThread* current) {
1475   assert(!SafepointSynchronize::is_at_safepoint(), "must NOT be at safepoint");
1476 
1477   DeoptimizationScope deopt_scope;
1478   {
1479     MutexLocker ml(current, Compile_lock);
1480 
1481     set_init_state(InstanceKlass::loaded);
1482     // make sure init_state store is already done.
1483     // The compiler reads the hierarchy outside of the Compile_lock.
1484     // Access ordering is used to add to hierarchy.
1485 
1486     // Link into hierarchy.
1487     append_to_sibling_list();                    // add to superklass/sibling list
1488     process_interfaces();                        // handle all "implements" declarations
1489 
1490     // Now mark all code that depended on old class hierarchy.
1491     // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1492     if (Universe::is_fully_initialized()) {
1493       CodeCache::mark_dependents_on(&deopt_scope, this);
1494     }
1495   }
1496   // Perform the deopt handshake outside Compile_lock.
1497   deopt_scope.deoptimize_marked();
1498 }
1499 
1500 
1501 InstanceKlass* InstanceKlass::implementor() const {
1502   InstanceKlass* volatile* ik = adr_implementor();
1503   if (ik == nullptr) {
1504     return nullptr;
1505   } else {
1506     // This load races with inserts, and therefore needs acquire.
1507     InstanceKlass* ikls = AtomicAccess::load_acquire(ik);
1508     if (ikls != nullptr && !ikls->is_loader_alive()) {
1509       return nullptr;  // don't return unloaded class
1510     } else {
1511       return ikls;
1512     }
1513   }
1514 }
1515 
1516 
1517 void InstanceKlass::set_implementor(InstanceKlass* ik) {
1518   assert_locked_or_safepoint(Compile_lock);
1519   assert(is_interface(), "not interface");
1520   InstanceKlass* volatile* addr = adr_implementor();
1521   assert(addr != nullptr, "null addr");
1522   if (addr != nullptr) {
1523     AtomicAccess::release_store(addr, ik);
1524   }
1525 }
1526 
1527 int  InstanceKlass::nof_implementors() const {
1528   InstanceKlass* ik = implementor();
1529   if (ik == nullptr) {
1530     return 0;
1531   } else if (ik != this) {
1532     return 1;
1533   } else {
1534     return 2;
1535   }
1536 }
1537 
1538 // The embedded _implementor field can only record one implementor.
1539 // When there are more than one implementors, the _implementor field
1540 // is set to the interface Klass* itself. Following are the possible
1541 // values for the _implementor field:
1542 //   null                  - no implementor
1543 //   implementor Klass*    - one implementor
1544 //   self                  - more than one implementor
1545 //
1546 // The _implementor field only exists for interfaces.
1547 void InstanceKlass::add_implementor(InstanceKlass* ik) {
1548   if (Universe::is_fully_initialized()) {
1549     assert_lock_strong(Compile_lock);
1550   }
1551   assert(is_interface(), "not interface");
1552   // Filter out my subinterfaces.
1553   // (Note: Interfaces are never on the subklass list.)
1554   if (ik->is_interface()) return;
1555 
1556   // Filter out subclasses whose supers already implement me.
1557   // (Note: CHA must walk subclasses of direct implementors
1558   // in order to locate indirect implementors.)
1559   InstanceKlass* super_ik = ik->super();
1560   if (super_ik != nullptr && super_ik->implements_interface(this))
1561     // We only need to check one immediate superclass, since the
1562     // implements_interface query looks at transitive_interfaces.
1563     // Any supers of the super have the same (or fewer) transitive_interfaces.
1564     return;
1565 
1566   InstanceKlass* iklass = implementor();
1567   if (iklass == nullptr) {
1568     set_implementor(ik);
1569   } else if (iklass != this && iklass != ik) {
1570     // There is already an implementor. Use itself as an indicator of
1571     // more than one implementors.
1572     set_implementor(this);
1573   }
1574 
1575   // The implementor also implements the transitive_interfaces
1576   for (int index = 0; index < local_interfaces()->length(); index++) {
1577     local_interfaces()->at(index)->add_implementor(ik);
1578   }
1579 }
1580 
1581 void InstanceKlass::init_implementor() {
1582   if (is_interface()) {
1583     set_implementor(nullptr);
1584   }
1585 }
1586 
1587 
1588 void InstanceKlass::process_interfaces() {
1589   // link this class into the implementors list of every interface it implements
1590   for (int i = local_interfaces()->length() - 1; i >= 0; i--) {
1591     assert(local_interfaces()->at(i)->is_klass(), "must be a klass");
1592     InstanceKlass* interf = local_interfaces()->at(i);
1593     assert(interf->is_interface(), "expected interface");
1594     interf->add_implementor(this);
1595   }
1596 }
1597 
1598 bool InstanceKlass::can_be_primary_super_slow() const {
1599   if (is_interface())
1600     return false;
1601   else
1602     return Klass::can_be_primary_super_slow();
1603 }
1604 
1605 GrowableArray<Klass*>* InstanceKlass::compute_secondary_supers(int num_extra_slots,
1606                                                                Array<InstanceKlass*>* transitive_interfaces) {
1607   // The secondaries are the implemented interfaces.
1608   // We need the cast because Array<Klass*> is NOT a supertype of Array<InstanceKlass*>,
1609   // (but it's safe to do here because we won't write into _secondary_supers from this point on).
1610   Array<Klass*>* interfaces = (Array<Klass*>*)(address)transitive_interfaces;
1611   int num_secondaries = num_extra_slots + interfaces->length();
1612   if (num_secondaries == 0) {
1613     // Must share this for correct bootstrapping!
1614     set_secondary_supers(Universe::the_empty_klass_array(), Universe::the_empty_klass_bitmap());
1615     return nullptr;
1616   } else if (num_extra_slots == 0 && interfaces->length() <= 1) {
1617     // We will reuse the transitive interfaces list if we're certain
1618     // it's in hash order.
1619     uintx bitmap = compute_secondary_supers_bitmap(interfaces);
1620     set_secondary_supers(interfaces, bitmap);
1621     return nullptr;
1622   }
1623   // Copy transitive interfaces to a temporary growable array to be constructed
1624   // into the secondary super list with extra slots.
1625   GrowableArray<Klass*>* secondaries = new GrowableArray<Klass*>(interfaces->length());
1626   for (int i = 0; i < interfaces->length(); i++) {
1627     secondaries->push(interfaces->at(i));
1628   }
1629   return secondaries;
1630 }
1631 
1632 bool InstanceKlass::implements_interface(Klass* k) const {
1633   if (this == k) return true;
1634   assert(k->is_interface(), "should be an interface class");
1635   for (int i = 0; i < transitive_interfaces()->length(); i++) {
1636     if (transitive_interfaces()->at(i) == k) {
1637       return true;
1638     }
1639   }
1640   return false;
1641 }
1642 
1643 bool InstanceKlass::is_same_or_direct_interface(Klass *k) const {
1644   // Verify direct super interface
1645   if (this == k) return true;
1646   assert(k->is_interface(), "should be an interface class");
1647   for (int i = 0; i < local_interfaces()->length(); i++) {
1648     if (local_interfaces()->at(i) == k) {
1649       return true;
1650     }
1651   }
1652   return false;
1653 }
1654 
1655 instanceOop InstanceKlass::register_finalizer(instanceOop i, TRAPS) {
1656   if (TraceFinalizerRegistration) {
1657     tty->print("Registered ");
1658     i->print_value_on(tty);
1659     tty->print_cr(" (" PTR_FORMAT ") as finalizable", p2i(i));
1660   }
1661   instanceHandle h_i(THREAD, i);
1662   // Pass the handle as argument, JavaCalls::call expects oop as jobjects
1663   JavaValue result(T_VOID);
1664   JavaCallArguments args(h_i);
1665   methodHandle mh(THREAD, Universe::finalizer_register_method());
1666   JavaCalls::call(&result, mh, &args, CHECK_NULL);
1667   MANAGEMENT_ONLY(FinalizerService::on_register(h_i(), THREAD);)
1668   return h_i();
1669 }
1670 
1671 instanceOop InstanceKlass::allocate_instance(TRAPS) {
1672   assert(!is_abstract() && !is_interface(), "Should not create this object");
1673   size_t size = size_helper();  // Query before forming handle.
1674   return (instanceOop)Universe::heap()->obj_allocate(this, size, CHECK_NULL);
1675 }
1676 
1677 instanceOop InstanceKlass::allocate_instance(oop java_class,
1678                                              const char* who,
1679                                              TRAPS) {
1680   Klass* k = java_lang_Class::as_Klass(java_class);
1681   if (k == nullptr) {
1682     ResourceMark rm(THREAD);
1683     THROW_(vmSymbols::java_lang_InstantiationException(), nullptr);
1684   }
1685   InstanceKlass* ik = cast(k);
1686   ik->check_valid_for_instantiation(false, CHECK_NULL);
1687   ik->initialize(CHECK_NULL);
1688   return ik->allocate_instance(THREAD);
1689 }
1690 
1691 instanceHandle InstanceKlass::allocate_instance_handle(TRAPS) {
1692   return instanceHandle(THREAD, allocate_instance(THREAD));
1693 }
1694 
1695 void InstanceKlass::check_valid_for_instantiation(bool throwError, TRAPS) {
1696   if (is_interface() || is_abstract()) {
1697     ResourceMark rm(THREAD);
1698     THROW_MSG(throwError ? vmSymbols::java_lang_InstantiationError()
1699               : vmSymbols::java_lang_InstantiationException(), external_name());
1700   }
1701   if (this == vmClasses::Class_klass()) {
1702     ResourceMark rm(THREAD);
1703     THROW_MSG(throwError ? vmSymbols::java_lang_IllegalAccessError()
1704               : vmSymbols::java_lang_IllegalAccessException(), external_name());
1705   }
1706 }
1707 
1708 ArrayKlass* InstanceKlass::array_klass(int n, TRAPS) {
1709   // Need load-acquire for lock-free read
1710   if (array_klasses_acquire() == nullptr) {
1711 
1712     // Recursively lock array allocation
1713     RecursiveLocker rl(MultiArray_lock, THREAD);
1714 
1715     // Check if another thread created the array klass while we were waiting for the lock.
1716     if (array_klasses() == nullptr) {
1717       ObjArrayKlass* k = ObjArrayKlass::allocate_objArray_klass(class_loader_data(), 1, this, CHECK_NULL);
1718       // use 'release' to pair with lock-free load
1719       release_set_array_klasses(k);
1720     }
1721   }
1722 
1723   // array_klasses() will always be set at this point
1724   ObjArrayKlass* ak = array_klasses();
1725   assert(ak != nullptr, "should be set");
1726   return ak->array_klass(n, THREAD);
1727 }
1728 
1729 ArrayKlass* InstanceKlass::array_klass_or_null(int n) {
1730   // Need load-acquire for lock-free read
1731   ObjArrayKlass* oak = array_klasses_acquire();
1732   if (oak == nullptr) {
1733     return nullptr;
1734   } else {
1735     return oak->array_klass_or_null(n);
1736   }
1737 }
1738 
1739 ArrayKlass* InstanceKlass::array_klass(TRAPS) {
1740   return array_klass(1, THREAD);
1741 }
1742 
1743 ArrayKlass* InstanceKlass::array_klass_or_null() {
1744   return array_klass_or_null(1);
1745 }
1746 
1747 Method* InstanceKlass::class_initializer() const {
1748   Method* clinit = find_method(
1749       vmSymbols::class_initializer_name(), vmSymbols::void_method_signature());
1750   if (clinit != nullptr && clinit->has_valid_initializer_flags()) {
1751     return clinit;
1752   }
1753   return nullptr;
1754 }
1755 
1756 void InstanceKlass::call_class_initializer(TRAPS) {
1757   if (ReplayCompiles &&
1758       (ReplaySuppressInitializers == 1 ||
1759        (ReplaySuppressInitializers >= 2 && class_loader() != nullptr))) {
1760     // Hide the existence of the initializer for the purpose of replaying the compile
1761     return;
1762   }
1763 
1764 #if INCLUDE_CDS
1765   // This is needed to ensure the consistency of the archived heap objects.
1766   if (has_aot_initialized_mirror() && CDSConfig::is_loading_heap()) {
1767     AOTClassInitializer::call_runtime_setup(THREAD, this);
1768     return;
1769   } else if (has_archived_enum_objs()) {
1770     assert(in_aot_cache(), "must be");
1771     bool initialized = CDSEnumKlass::initialize_enum_klass(this, CHECK);
1772     if (initialized) {
1773       return;
1774     }
1775   }
1776 #endif
1777 
1778   methodHandle h_method(THREAD, class_initializer());
1779   assert(!is_initialized(), "we cannot initialize twice");
1780 
1781 #if 0
1782   // FIXME -- revive this code added to leyden/premain for <clinit> profiling
1783   int init_id = log_class_init(THREAD, this);
1784   if (h_method() != nullptr) {
1785     JavaCallArguments args; // No arguments
1786     JavaValue result(T_VOID);
1787     InstanceKlass* outer = THREAD->set_class_being_initialized(this);
1788     jlong bc_start = (CountBytecodesPerThread ? THREAD->bc_counter_value() : BytecodeCounter::counter_value());
1789 
1790     elapsedTimer timer;
1791     {
1792       PerfPauseTimer pt(THREAD->current_rt_call_timer(), THREAD->profile_rt_calls());
1793       PauseRuntimeCallProfiling prcp(THREAD, THREAD->profile_rt_calls());
1794 
1795       timer.start();
1796       JavaCalls::call(&result, h_method, &args, THREAD); // Static call (no args)
1797       timer.stop();
1798     }
1799 
1800     jlong bc_end = (CountBytecodesPerThread ? THREAD->bc_counter_value() : BytecodeCounter::counter_value());
1801 
1802     jlong bc_executed = (bc_end - bc_start);
1803     if (UsePerfData && outer == nullptr) { // outermost clinit
1804       THREAD->inc_clinit_bc_counter_value(bc_executed);
1805       ClassLoader::perf_class_init_bytecodes_count()->inc(bc_executed);
1806     }
1807 
1808     THREAD->set_class_being_initialized(outer);
1809 
1810     LogStreamHandle(Debug, init) log;
1811     if (log.is_enabled()) {
1812       ResourceMark rm(THREAD);
1813       log.print("%d Initialized in %.3fms (total: " JLONG_FORMAT "ms); ",
1814                 init_id, timer.seconds() * 1000.0, ClassLoader::class_init_time_ms());
1815       if (CountBytecodes || CountBytecodesPerThread) {
1816         log.print("executed " JLONG_FORMAT " bytecodes; ", bc_executed);
1817       }
1818       name()->print_value_on(&log);
1819       log.print_cr(" by thread " PTR_FORMAT " \"%s\" (" PTR_FORMAT ")",
1820                    p2i(THREAD), THREAD->name(), p2i(this));
1821     }
1822   }
1823   LogTarget(Info, class, init) lt;
1824   if (lt.is_enabled()) {
1825     ResourceMark rm(THREAD);
1826     LogStream ls(lt);
1827     ls.print("%d Initialized ", init_id);
1828     name()->print_value_on(&ls);
1829     ls.print_cr("%s (" PTR_FORMAT ") by thread \"%s\"",
1830                 h_method() == nullptr ? "(no method)" : "", p2i(this),
1831                 THREAD->name());
1832   }
1833 #else
1834   LogTarget(Info, class, init) lt;
1835   if (lt.is_enabled()) {
1836     ResourceMark rm(THREAD);
1837     LogStream ls(lt);
1838     ls.print("%d Initializing ", call_class_initializer_counter++);
1839     name()->print_value_on(&ls);
1840     ls.print_cr("%s (" PTR_FORMAT ") by thread \"%s\"",
1841                 h_method() == nullptr ? "(no method)" : "", p2i(this),
1842                 THREAD->name());
1843   }
1844   if (h_method() != nullptr) {
1845     ThreadInClassInitializer ticl(THREAD, this); // Track class being initialized
1846     JavaCallArguments args; // No arguments
1847     JavaValue result(T_VOID);
1848     JavaCalls::call(&result, h_method, &args, CHECK); // Static call (no args)
1849   }
1850 #endif
1851 }
1852 
1853 // If a class that implements this interface is initialized, is the JVM required
1854 // to first execute a <clinit> method declared in this interface,
1855 // or (if also_check_supers==true) any of the super types of this interface?
1856 //
1857 // JVMS 5.5. Initialization, step 7: Next, if C is a class rather than
1858 // an interface, then let SC be its superclass and let SI1, ..., SIn
1859 // be all superinterfaces of C (whether direct or indirect) that
1860 // declare at least one non-abstract, non-static method.
1861 //
1862 // So when an interface is initialized, it does not look at its
1863 // supers. But a proper class will ensure that all of its supers have
1864 // run their <clinit> methods, except that it disregards interfaces
1865 // that lack a non-static concrete method (i.e., a default method).
1866 // Therefore, you should probably call this method only when the
1867 // current class is a super of some proper class, not an interface.
1868 bool InstanceKlass::interface_needs_clinit_execution_as_super(bool also_check_supers) const {
1869   assert(is_interface(), "must be");
1870 
1871   if (!has_nonstatic_concrete_methods()) {
1872     // quick check: no nonstatic concrete methods are declared by this or any super interfaces
1873     return false;
1874   }
1875 
1876   // JVMS 5.5. Initialization
1877   // ...If C is an interface that declares a non-abstract,
1878   // non-static method, the initialization of a class that
1879   // implements C directly or indirectly.
1880   if (declares_nonstatic_concrete_methods() && class_initializer() != nullptr) {
1881     return true;
1882   }
1883   if (also_check_supers) {
1884     Array<InstanceKlass*>* all_ifs = transitive_interfaces();
1885     for (int i = 0; i < all_ifs->length(); ++i) {
1886       InstanceKlass* super_intf = all_ifs->at(i);
1887       if (super_intf->declares_nonstatic_concrete_methods() && super_intf->class_initializer() != nullptr) {
1888         return true;
1889       }
1890     }
1891   }
1892   return false;
1893 }
1894 
1895 void InstanceKlass::mask_for(const methodHandle& method, int bci,
1896   InterpreterOopMap* entry_for) {
1897   // Lazily create the _oop_map_cache at first request.
1898   // Load_acquire is needed to safely get instance published with CAS by another thread.
1899   OopMapCache* oop_map_cache = AtomicAccess::load_acquire(&_oop_map_cache);
1900   if (oop_map_cache == nullptr) {
1901     // Try to install new instance atomically.
1902     oop_map_cache = new OopMapCache();
1903     OopMapCache* other = AtomicAccess::cmpxchg(&_oop_map_cache, (OopMapCache*)nullptr, oop_map_cache);
1904     if (other != nullptr) {
1905       // Someone else managed to install before us, ditch local copy and use the existing one.
1906       delete oop_map_cache;
1907       oop_map_cache = other;
1908     }
1909   }
1910   // _oop_map_cache is constant after init; lookup below does its own locking.
1911   oop_map_cache->lookup(method, bci, entry_for);
1912 }
1913 
1914 bool InstanceKlass::contains_field_offset(int offset) {
1915   fieldDescriptor fd;
1916   return find_field_from_offset(offset, false, &fd);
1917 }
1918 
1919 FieldInfo InstanceKlass::field(int index) const {
1920   for (AllFieldStream fs(this); !fs.done(); fs.next()) {
1921     if (fs.index() == index) {
1922       return fs.to_FieldInfo();
1923     }
1924   }
1925   fatal("Field not found");
1926   return FieldInfo();
1927 }
1928 
1929 bool InstanceKlass::find_local_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
1930   JavaFieldStream fs(this);
1931   if (fs.lookup(name, sig)) {
1932     assert(fs.name() == name, "name must match");
1933     assert(fs.signature() == sig, "signature must match");
1934     fd->reinitialize(const_cast<InstanceKlass*>(this), fs.to_FieldInfo());
1935     return true;
1936   }
1937   return false;
1938 }
1939 
1940 
1941 Klass* InstanceKlass::find_interface_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
1942   const int n = local_interfaces()->length();
1943   for (int i = 0; i < n; i++) {
1944     InstanceKlass* intf1 = local_interfaces()->at(i);
1945     assert(intf1->is_interface(), "just checking type");
1946     // search for field in current interface
1947     if (intf1->find_local_field(name, sig, fd)) {
1948       assert(fd->is_static(), "interface field must be static");
1949       return intf1;
1950     }
1951     // search for field in direct superinterfaces
1952     Klass* intf2 = intf1->find_interface_field(name, sig, fd);
1953     if (intf2 != nullptr) return intf2;
1954   }
1955   // otherwise field lookup fails
1956   return nullptr;
1957 }
1958 
1959 
1960 Klass* InstanceKlass::find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
1961   // search order according to newest JVM spec (5.4.3.2, p.167).
1962   // 1) search for field in current klass
1963   if (find_local_field(name, sig, fd)) {
1964     return const_cast<InstanceKlass*>(this);
1965   }
1966   // 2) search for field recursively in direct superinterfaces
1967   { Klass* intf = find_interface_field(name, sig, fd);
1968     if (intf != nullptr) return intf;
1969   }
1970   // 3) apply field lookup recursively if superclass exists
1971   { InstanceKlass* supr = super();
1972     if (supr != nullptr) return supr->find_field(name, sig, fd);
1973   }
1974   // 4) otherwise field lookup fails
1975   return nullptr;
1976 }
1977 
1978 
1979 Klass* InstanceKlass::find_field(Symbol* name, Symbol* sig, bool is_static, fieldDescriptor* fd) const {
1980   // search order according to newest JVM spec (5.4.3.2, p.167).
1981   // 1) search for field in current klass
1982   if (find_local_field(name, sig, fd)) {
1983     if (fd->is_static() == is_static) return const_cast<InstanceKlass*>(this);
1984   }
1985   // 2) search for field recursively in direct superinterfaces
1986   if (is_static) {
1987     Klass* intf = find_interface_field(name, sig, fd);
1988     if (intf != nullptr) return intf;
1989   }
1990   // 3) apply field lookup recursively if superclass exists
1991   { InstanceKlass* supr = super();
1992     if (supr != nullptr) return supr->find_field(name, sig, is_static, fd);
1993   }
1994   // 4) otherwise field lookup fails
1995   return nullptr;
1996 }
1997 
1998 
1999 bool InstanceKlass::find_local_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const {
2000   for (JavaFieldStream fs(this); !fs.done(); fs.next()) {
2001     if (fs.offset() == offset) {
2002       fd->reinitialize(const_cast<InstanceKlass*>(this), fs.to_FieldInfo());
2003       if (fd->is_static() == is_static) return true;
2004     }
2005   }
2006   return false;
2007 }
2008 
2009 
2010 bool InstanceKlass::find_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const {
2011   const InstanceKlass* klass = this;
2012   while (klass != nullptr) {
2013     if (klass->find_local_field_from_offset(offset, is_static, fd)) {
2014       return true;
2015     }
2016     klass = klass->super();
2017   }
2018   return false;
2019 }
2020 
2021 
2022 void InstanceKlass::methods_do(void f(Method* method)) {
2023   // Methods aren't stable until they are loaded.  This can be read outside
2024   // a lock through the ClassLoaderData for profiling
2025   // Redefined scratch classes are on the list and need to be cleaned
2026   if (!is_loaded() && !is_scratch_class()) {
2027     return;
2028   }
2029 
2030   int len = methods()->length();
2031   for (int index = 0; index < len; index++) {
2032     Method* m = methods()->at(index);
2033     assert(m->is_method(), "must be method");
2034     f(m);
2035   }
2036 }
2037 
2038 
2039 void InstanceKlass::do_local_static_fields(FieldClosure* cl) {
2040   for (JavaFieldStream fs(this); !fs.done(); fs.next()) {
2041     if (fs.access_flags().is_static()) {
2042       fieldDescriptor& fd = fs.field_descriptor();
2043       cl->do_field(&fd);
2044     }
2045   }
2046 }
2047 
2048 
2049 void InstanceKlass::do_local_static_fields(void f(fieldDescriptor*, Handle, TRAPS), Handle mirror, TRAPS) {
2050   for (JavaFieldStream fs(this); !fs.done(); fs.next()) {
2051     if (fs.access_flags().is_static()) {
2052       fieldDescriptor& fd = fs.field_descriptor();
2053       f(&fd, mirror, CHECK);
2054     }
2055   }
2056 }
2057 
2058 void InstanceKlass::do_nonstatic_fields(FieldClosure* cl) {
2059   InstanceKlass* super = this->super();
2060   if (super != nullptr) {
2061     super->do_nonstatic_fields(cl);
2062   }
2063   for (JavaFieldStream fs(this); !fs.done(); fs.next()) {
2064     fieldDescriptor& fd = fs.field_descriptor();
2065     if (!fd.is_static()) {
2066       cl->do_field(&fd);
2067     }
2068   }
2069 }
2070 
2071 static int compare_fields_by_offset(FieldInfo* a, FieldInfo* b) {
2072   return a->offset() - b->offset();
2073 }
2074 
2075 void InstanceKlass::print_nonstatic_fields(FieldClosure* cl) {
2076   InstanceKlass* super = this->super();
2077   if (super != nullptr) {
2078     super->print_nonstatic_fields(cl);
2079   }
2080   ResourceMark rm;
2081   // In DebugInfo nonstatic fields are sorted by offset.
2082   GrowableArray<FieldInfo> fields_sorted;
2083   for (AllFieldStream fs(this); !fs.done(); fs.next()) {
2084     if (!fs.access_flags().is_static()) {
2085       fields_sorted.push(fs.to_FieldInfo());
2086     }
2087   }
2088   int length = fields_sorted.length();
2089   if (length > 0) {
2090     fields_sorted.sort(compare_fields_by_offset);
2091     fieldDescriptor fd;
2092     for (int i = 0; i < length; i++) {
2093       fd.reinitialize(this, fields_sorted.at(i));
2094       assert(!fd.is_static() && fd.offset() == checked_cast<int>(fields_sorted.at(i).offset()), "only nonstatic fields");
2095       cl->do_field(&fd);
2096     }
2097   }
2098 }
2099 
2100 #ifdef ASSERT
2101 static int linear_search(const Array<Method*>* methods,
2102                          const Symbol* name,
2103                          const Symbol* signature) {
2104   const int len = methods->length();
2105   for (int index = 0; index < len; index++) {
2106     const Method* const m = methods->at(index);
2107     assert(m->is_method(), "must be method");
2108     if (m->signature() == signature && m->name() == name) {
2109        return index;
2110     }
2111   }
2112   return -1;
2113 }
2114 #endif
2115 
2116 bool InstanceKlass::_disable_method_binary_search = false;
2117 
2118 NOINLINE int linear_search(const Array<Method*>* methods, const Symbol* name) {
2119   int len = methods->length();
2120   int l = 0;
2121   int h = len - 1;
2122   while (l <= h) {
2123     Method* m = methods->at(l);
2124     if (m->name() == name) {
2125       return l;
2126     }
2127     l++;
2128   }
2129   return -1;
2130 }
2131 
2132 inline int InstanceKlass::quick_search(const Array<Method*>* methods, const Symbol* name) {
2133   if (_disable_method_binary_search) {
2134     assert(CDSConfig::is_dumping_dynamic_archive(), "must be");
2135     // At the final stage of dynamic dumping, the methods array may not be sorted
2136     // by ascending addresses of their names, so we can't use binary search anymore.
2137     // However, methods with the same name are still laid out consecutively inside the
2138     // methods array, so let's look for the first one that matches.
2139     return linear_search(methods, name);
2140   }
2141 
2142   int len = methods->length();
2143   int l = 0;
2144   int h = len - 1;
2145 
2146   // methods are sorted by ascending addresses of their names, so do binary search
2147   while (l <= h) {
2148     int mid = (l + h) >> 1;
2149     Method* m = methods->at(mid);
2150     assert(m->is_method(), "must be method");
2151     int res = m->name()->fast_compare(name);
2152     if (res == 0) {
2153       return mid;
2154     } else if (res < 0) {
2155       l = mid + 1;
2156     } else {
2157       h = mid - 1;
2158     }
2159   }
2160   return -1;
2161 }
2162 
2163 // find_method looks up the name/signature in the local methods array
2164 Method* InstanceKlass::find_method(const Symbol* name,
2165                                    const Symbol* signature) const {
2166   return find_method_impl(name, signature,
2167                           OverpassLookupMode::find,
2168                           StaticLookupMode::find,
2169                           PrivateLookupMode::find);
2170 }
2171 
2172 Method* InstanceKlass::find_method_impl(const Symbol* name,
2173                                         const Symbol* signature,
2174                                         OverpassLookupMode overpass_mode,
2175                                         StaticLookupMode static_mode,
2176                                         PrivateLookupMode private_mode) const {
2177   return InstanceKlass::find_method_impl(methods(),
2178                                          name,
2179                                          signature,
2180                                          overpass_mode,
2181                                          static_mode,
2182                                          private_mode);
2183 }
2184 
2185 // find_instance_method looks up the name/signature in the local methods array
2186 // and skips over static methods
2187 Method* InstanceKlass::find_instance_method(const Array<Method*>* methods,
2188                                             const Symbol* name,
2189                                             const Symbol* signature,
2190                                             PrivateLookupMode private_mode) {
2191   Method* const meth = InstanceKlass::find_method_impl(methods,
2192                                                  name,
2193                                                  signature,
2194                                                  OverpassLookupMode::find,
2195                                                  StaticLookupMode::skip,
2196                                                  private_mode);
2197   assert(((meth == nullptr) || !meth->is_static()),
2198     "find_instance_method should have skipped statics");
2199   return meth;
2200 }
2201 
2202 // find_instance_method looks up the name/signature in the local methods array
2203 // and skips over static methods
2204 Method* InstanceKlass::find_instance_method(const Symbol* name,
2205                                             const Symbol* signature,
2206                                             PrivateLookupMode private_mode) const {
2207   return InstanceKlass::find_instance_method(methods(), name, signature, private_mode);
2208 }
2209 
2210 // Find looks up the name/signature in the local methods array
2211 // and filters on the overpass, static and private flags
2212 // This returns the first one found
2213 // note that the local methods array can have up to one overpass, one static
2214 // and one instance (private or not) with the same name/signature
2215 Method* InstanceKlass::find_local_method(const Symbol* name,
2216                                          const Symbol* signature,
2217                                          OverpassLookupMode overpass_mode,
2218                                          StaticLookupMode static_mode,
2219                                          PrivateLookupMode private_mode) const {
2220   return InstanceKlass::find_method_impl(methods(),
2221                                          name,
2222                                          signature,
2223                                          overpass_mode,
2224                                          static_mode,
2225                                          private_mode);
2226 }
2227 
2228 // Find looks up the name/signature in the local methods array
2229 // and filters on the overpass, static and private flags
2230 // This returns the first one found
2231 // note that the local methods array can have up to one overpass, one static
2232 // and one instance (private or not) with the same name/signature
2233 Method* InstanceKlass::find_local_method(const Array<Method*>* methods,
2234                                          const Symbol* name,
2235                                          const Symbol* signature,
2236                                          OverpassLookupMode overpass_mode,
2237                                          StaticLookupMode static_mode,
2238                                          PrivateLookupMode private_mode) {
2239   return InstanceKlass::find_method_impl(methods,
2240                                          name,
2241                                          signature,
2242                                          overpass_mode,
2243                                          static_mode,
2244                                          private_mode);
2245 }
2246 
2247 Method* InstanceKlass::find_method(const Array<Method*>* methods,
2248                                    const Symbol* name,
2249                                    const Symbol* signature) {
2250   return InstanceKlass::find_method_impl(methods,
2251                                          name,
2252                                          signature,
2253                                          OverpassLookupMode::find,
2254                                          StaticLookupMode::find,
2255                                          PrivateLookupMode::find);
2256 }
2257 
2258 Method* InstanceKlass::find_method_impl(const Array<Method*>* methods,
2259                                         const Symbol* name,
2260                                         const Symbol* signature,
2261                                         OverpassLookupMode overpass_mode,
2262                                         StaticLookupMode static_mode,
2263                                         PrivateLookupMode private_mode) {
2264   int hit = find_method_index(methods, name, signature, overpass_mode, static_mode, private_mode);
2265   return hit >= 0 ? methods->at(hit): nullptr;
2266 }
2267 
2268 // true if method matches signature and conforms to skipping_X conditions.
2269 static bool method_matches(const Method* m,
2270                            const Symbol* signature,
2271                            bool skipping_overpass,
2272                            bool skipping_static,
2273                            bool skipping_private) {
2274   return ((m->signature() == signature) &&
2275     (!skipping_overpass || !m->is_overpass()) &&
2276     (!skipping_static || !m->is_static()) &&
2277     (!skipping_private || !m->is_private()));
2278 }
2279 
2280 // Used directly for default_methods to find the index into the
2281 // default_vtable_indices, and indirectly by find_method
2282 // find_method_index looks in the local methods array to return the index
2283 // of the matching name/signature. If, overpass methods are being ignored,
2284 // the search continues to find a potential non-overpass match.  This capability
2285 // is important during method resolution to prefer a static method, for example,
2286 // over an overpass method.
2287 // There is the possibility in any _method's array to have the same name/signature
2288 // for a static method, an overpass method and a local instance method
2289 // To correctly catch a given method, the search criteria may need
2290 // to explicitly skip the other two. For local instance methods, it
2291 // is often necessary to skip private methods
2292 int InstanceKlass::find_method_index(const Array<Method*>* methods,
2293                                      const Symbol* name,
2294                                      const Symbol* signature,
2295                                      OverpassLookupMode overpass_mode,
2296                                      StaticLookupMode static_mode,
2297                                      PrivateLookupMode private_mode) {
2298   const bool skipping_overpass = (overpass_mode == OverpassLookupMode::skip);
2299   const bool skipping_static = (static_mode == StaticLookupMode::skip);
2300   const bool skipping_private = (private_mode == PrivateLookupMode::skip);
2301   const int hit = quick_search(methods, name);
2302   if (hit != -1) {
2303     const Method* const m = methods->at(hit);
2304 
2305     // Do linear search to find matching signature.  First, quick check
2306     // for common case, ignoring overpasses if requested.
2307     if (method_matches(m, signature, skipping_overpass, skipping_static, skipping_private)) {
2308       return hit;
2309     }
2310 
2311     // search downwards through overloaded methods
2312     int i;
2313     for (i = hit - 1; i >= 0; --i) {
2314         const Method* const m = methods->at(i);
2315         assert(m->is_method(), "must be method");
2316         if (m->name() != name) {
2317           break;
2318         }
2319         if (method_matches(m, signature, skipping_overpass, skipping_static, skipping_private)) {
2320           return i;
2321         }
2322     }
2323     // search upwards
2324     for (i = hit + 1; i < methods->length(); ++i) {
2325         const Method* const m = methods->at(i);
2326         assert(m->is_method(), "must be method");
2327         if (m->name() != name) {
2328           break;
2329         }
2330         if (method_matches(m, signature, skipping_overpass, skipping_static, skipping_private)) {
2331           return i;
2332         }
2333     }
2334     // not found
2335 #ifdef ASSERT
2336     const int index = (skipping_overpass || skipping_static || skipping_private) ? -1 :
2337       linear_search(methods, name, signature);
2338     assert(-1 == index, "binary search should have found entry %d", index);
2339 #endif
2340   }
2341   return -1;
2342 }
2343 
2344 int InstanceKlass::find_method_by_name(const Symbol* name, int* end) const {
2345   return find_method_by_name(methods(), name, end);
2346 }
2347 
2348 int InstanceKlass::find_method_by_name(const Array<Method*>* methods,
2349                                        const Symbol* name,
2350                                        int* end_ptr) {
2351   assert(end_ptr != nullptr, "just checking");
2352   int start = quick_search(methods, name);
2353   int end = start + 1;
2354   if (start != -1) {
2355     while (start - 1 >= 0 && (methods->at(start - 1))->name() == name) --start;
2356     while (end < methods->length() && (methods->at(end))->name() == name) ++end;
2357     *end_ptr = end;
2358     return start;
2359   }
2360   return -1;
2361 }
2362 
2363 // uncached_lookup_method searches both the local class methods array and all
2364 // superclasses methods arrays, skipping any overpass methods in superclasses,
2365 // and possibly skipping private methods.
2366 Method* InstanceKlass::uncached_lookup_method(const Symbol* name,
2367                                               const Symbol* signature,
2368                                               OverpassLookupMode overpass_mode,
2369                                               PrivateLookupMode private_mode) const {
2370   OverpassLookupMode overpass_local_mode = overpass_mode;
2371   const InstanceKlass* klass = this;
2372   while (klass != nullptr) {
2373     Method* const method = klass->find_method_impl(name,
2374                                                    signature,
2375                                                    overpass_local_mode,
2376                                                    StaticLookupMode::find,
2377                                                    private_mode);
2378     if (method != nullptr) {
2379       return method;
2380     }
2381     klass = klass->super();
2382     overpass_local_mode = OverpassLookupMode::skip;   // Always ignore overpass methods in superclasses
2383   }
2384   return nullptr;
2385 }
2386 
2387 #ifdef ASSERT
2388 // search through class hierarchy and return true if this class or
2389 // one of the superclasses was redefined
2390 bool InstanceKlass::has_redefined_this_or_super() const {
2391   const InstanceKlass* klass = this;
2392   while (klass != nullptr) {
2393     if (klass->has_been_redefined()) {
2394       return true;
2395     }
2396     klass = klass->super();
2397   }
2398   return false;
2399 }
2400 #endif
2401 
2402 // lookup a method in the default methods list then in all transitive interfaces
2403 // Do NOT return private or static methods
2404 Method* InstanceKlass::lookup_method_in_ordered_interfaces(Symbol* name,
2405                                                          Symbol* signature) const {
2406   Method* m = nullptr;
2407   if (default_methods() != nullptr) {
2408     m = find_method(default_methods(), name, signature);
2409   }
2410   // Look up interfaces
2411   if (m == nullptr) {
2412     m = lookup_method_in_all_interfaces(name, signature, DefaultsLookupMode::find);
2413   }
2414   return m;
2415 }
2416 
2417 // lookup a method in all the interfaces that this class implements
2418 // Do NOT return private or static methods, new in JDK8 which are not externally visible
2419 // They should only be found in the initial InterfaceMethodRef
2420 Method* InstanceKlass::lookup_method_in_all_interfaces(Symbol* name,
2421                                                        Symbol* signature,
2422                                                        DefaultsLookupMode defaults_mode) const {
2423   Array<InstanceKlass*>* all_ifs = transitive_interfaces();
2424   int num_ifs = all_ifs->length();
2425   InstanceKlass *ik = nullptr;
2426   for (int i = 0; i < num_ifs; i++) {
2427     ik = all_ifs->at(i);
2428     Method* m = ik->lookup_method(name, signature);
2429     if (m != nullptr && m->is_public() && !m->is_static() &&
2430         ((defaults_mode != DefaultsLookupMode::skip) || !m->is_default_method())) {
2431       return m;
2432     }
2433   }
2434   return nullptr;
2435 }
2436 
2437 PrintClassClosure::PrintClassClosure(outputStream* st, bool verbose)
2438   :_st(st), _verbose(verbose) {
2439   ResourceMark rm;
2440   _st->print("%-18s  ", "KlassAddr");
2441   _st->print("%-4s  ", "Size");
2442   _st->print("%-20s  ", "State");
2443   _st->print("%-7s  ", "Flags");
2444   _st->print("%-5s  ", "ClassName");
2445   _st->cr();
2446 }
2447 
2448 void PrintClassClosure::do_klass(Klass* k)  {
2449   ResourceMark rm;
2450   // klass pointer
2451   _st->print(PTR_FORMAT "  ", p2i(k));
2452   // klass size
2453   _st->print("%4d  ", k->size());
2454   // initialization state
2455   if (k->is_instance_klass()) {
2456     _st->print("%-20s  ",InstanceKlass::cast(k)->init_state_name());
2457   } else {
2458     _st->print("%-20s  ","");
2459   }
2460   // misc flags(Changes should synced with ClassesDCmd::ClassesDCmd help doc)
2461   char buf[10];
2462   int i = 0;
2463   if (k->has_finalizer()) buf[i++] = 'F';
2464   if (k->is_instance_klass()) {
2465     InstanceKlass* ik = InstanceKlass::cast(k);
2466     if (ik->has_final_method()) buf[i++] = 'f';
2467     if (ik->is_rewritten()) buf[i++] = 'W';
2468     if (ik->is_contended()) buf[i++] = 'C';
2469     if (ik->has_been_redefined()) buf[i++] = 'R';
2470     if (ik->in_aot_cache()) buf[i++] = 'S';
2471   }
2472   buf[i++] = '\0';
2473   _st->print("%-7s  ", buf);
2474   // klass name
2475   _st->print("%-5s  ", k->external_name());
2476   // end
2477   _st->cr();
2478   if (_verbose) {
2479     k->print_on(_st);
2480   }
2481 }
2482 
2483 /* jni_id_for for jfieldIds only */
2484 JNIid* InstanceKlass::jni_id_for(int offset) {
2485   MutexLocker ml(JfieldIdCreation_lock);
2486   JNIid* probe = jni_ids() == nullptr ? nullptr : jni_ids()->find(offset);
2487   if (probe == nullptr) {
2488     // Allocate new static field identifier
2489     probe = new JNIid(this, offset, jni_ids());
2490     set_jni_ids(probe);
2491   }
2492   return probe;
2493 }
2494 
2495 u2 InstanceKlass::enclosing_method_data(int offset) const {
2496   const Array<jushort>* const inner_class_list = inner_classes();
2497   if (inner_class_list == nullptr) {
2498     return 0;
2499   }
2500   const int length = inner_class_list->length();
2501   if (length % inner_class_next_offset == 0) {
2502     return 0;
2503   }
2504   const int index = length - enclosing_method_attribute_size;
2505   assert(offset < enclosing_method_attribute_size, "invalid offset");
2506   return inner_class_list->at(index + offset);
2507 }
2508 
2509 void InstanceKlass::set_enclosing_method_indices(u2 class_index,
2510                                                  u2 method_index) {
2511   Array<jushort>* inner_class_list = inner_classes();
2512   assert (inner_class_list != nullptr, "_inner_classes list is not set up");
2513   int length = inner_class_list->length();
2514   if (length % inner_class_next_offset == enclosing_method_attribute_size) {
2515     int index = length - enclosing_method_attribute_size;
2516     inner_class_list->at_put(
2517       index + enclosing_method_class_index_offset, class_index);
2518     inner_class_list->at_put(
2519       index + enclosing_method_method_index_offset, method_index);
2520   }
2521 }
2522 
2523 jmethodID InstanceKlass::update_jmethod_id(jmethodID* jmeths, Method* method, int idnum) {
2524   if (method->is_old() && !method->is_obsolete()) {
2525     // If the method passed in is old (but not obsolete), use the current version.
2526     method = method_with_idnum((int)idnum);
2527     assert(method != nullptr, "old and but not obsolete, so should exist");
2528   }
2529   jmethodID new_id = Method::make_jmethod_id(class_loader_data(), method);
2530   AtomicAccess::release_store(&jmeths[idnum + 1], new_id);
2531   return new_id;
2532 }
2533 
2534 // Allocate the jmethodID cache.
2535 static jmethodID* create_jmethod_id_cache(size_t size) {
2536   jmethodID* jmeths = NEW_C_HEAP_ARRAY(jmethodID, size + 1, mtClass);
2537   memset(jmeths, 0, (size + 1) * sizeof(jmethodID));
2538   // cache size is stored in element[0], other elements offset by one
2539   jmeths[0] = (jmethodID)size;
2540   return jmeths;
2541 }
2542 
2543 // When reading outside a lock, use this.
2544 jmethodID* InstanceKlass::methods_jmethod_ids_acquire() const {
2545   return AtomicAccess::load_acquire(&_methods_jmethod_ids);
2546 }
2547 
2548 void InstanceKlass::release_set_methods_jmethod_ids(jmethodID* jmeths) {
2549   AtomicAccess::release_store(&_methods_jmethod_ids, jmeths);
2550 }
2551 
2552 // Lookup or create a jmethodID.
2553 jmethodID InstanceKlass::get_jmethod_id(Method* method) {
2554   int idnum = method->method_idnum();
2555   jmethodID* jmeths = methods_jmethod_ids_acquire();
2556 
2557   // We use a double-check locking idiom here because this cache is
2558   // performance sensitive. In the normal system, this cache only
2559   // transitions from null to non-null which is safe because we use
2560   // release_set_methods_jmethod_ids() to advertise the new cache.
2561   // A partially constructed cache should never be seen by a racing
2562   // thread. We also use release_store() to save a new jmethodID
2563   // in the cache so a partially constructed jmethodID should never be
2564   // seen either. Cache reads of existing jmethodIDs proceed without a
2565   // lock, but cache writes of a new jmethodID requires uniqueness and
2566   // creation of the cache itself requires no leaks so a lock is
2567   // acquired in those two cases.
2568   //
2569   // If the RedefineClasses() API has been used, then this cache grows
2570   // in the redefinition safepoint.
2571 
2572   if (jmeths == nullptr) {
2573     MutexLocker ml(JmethodIdCreation_lock, Mutex::_no_safepoint_check_flag);
2574     jmeths = _methods_jmethod_ids;
2575     // Still null?
2576     if (jmeths == nullptr) {
2577       size_t size = idnum_allocated_count();
2578       assert(size > (size_t)idnum, "should already have space");
2579       jmeths = create_jmethod_id_cache(size);
2580       jmethodID new_id = update_jmethod_id(jmeths, method, idnum);
2581 
2582       // publish jmeths
2583       release_set_methods_jmethod_ids(jmeths);
2584       return new_id;
2585     }
2586   }
2587 
2588   jmethodID id = AtomicAccess::load_acquire(&jmeths[idnum + 1]);
2589   if (id == nullptr) {
2590     MutexLocker ml(JmethodIdCreation_lock, Mutex::_no_safepoint_check_flag);
2591     id = jmeths[idnum + 1];
2592     // Still null?
2593     if (id == nullptr) {
2594       return update_jmethod_id(jmeths, method, idnum);
2595     }
2596   }
2597   return id;
2598 }
2599 
2600 void InstanceKlass::update_methods_jmethod_cache() {
2601   assert(SafepointSynchronize::is_at_safepoint(), "only called at safepoint");
2602   jmethodID* cache = _methods_jmethod_ids;
2603   if (cache != nullptr) {
2604     size_t size = idnum_allocated_count();
2605     size_t old_size = (size_t)cache[0];
2606     if (old_size < size + 1) {
2607       // Allocate a larger one and copy entries to the new one.
2608       // They've already been updated to point to new methods where applicable (i.e., not obsolete).
2609       jmethodID* new_cache = create_jmethod_id_cache(size);
2610 
2611       for (int i = 1; i <= (int)old_size; i++) {
2612         new_cache[i] = cache[i];
2613       }
2614       _methods_jmethod_ids = new_cache;
2615       FREE_C_HEAP_ARRAY(jmethodID, cache);
2616     }
2617   }
2618 }
2619 
2620 // Make a jmethodID for all methods in this class.  This makes getting all method
2621 // ids much, much faster with classes with more than 8
2622 // methods, and has a *substantial* effect on performance with jvmti
2623 // code that loads all jmethodIDs for all classes.
2624 void InstanceKlass::make_methods_jmethod_ids() {
2625   MutexLocker ml(JmethodIdCreation_lock, Mutex::_no_safepoint_check_flag);
2626   jmethodID* jmeths = _methods_jmethod_ids;
2627   if (jmeths == nullptr) {
2628     jmeths = create_jmethod_id_cache(idnum_allocated_count());
2629     release_set_methods_jmethod_ids(jmeths);
2630   }
2631 
2632   int length = methods()->length();
2633   for (int index = 0; index < length; index++) {
2634     Method* m = methods()->at(index);
2635     int idnum = m->method_idnum();
2636     assert(!m->is_old(), "should not have old methods or I'm confused");
2637     jmethodID id = AtomicAccess::load_acquire(&jmeths[idnum + 1]);
2638     if (!m->is_overpass() &&  // skip overpasses
2639         id == nullptr) {
2640       id = Method::make_jmethod_id(class_loader_data(), m);
2641       AtomicAccess::release_store(&jmeths[idnum + 1], id);
2642     }
2643   }
2644 }
2645 
2646 // Lookup a jmethodID, null if not found.  Do no blocking, no allocations, no handles
2647 jmethodID InstanceKlass::jmethod_id_or_null(Method* method) {
2648   int idnum = method->method_idnum();
2649   jmethodID* jmeths = methods_jmethod_ids_acquire();
2650   return (jmeths != nullptr) ? jmeths[idnum + 1] : nullptr;
2651 }
2652 
2653 inline DependencyContext InstanceKlass::dependencies() {
2654   DependencyContext dep_context(&_dep_context, &_dep_context_last_cleaned);
2655   return dep_context;
2656 }
2657 
2658 void InstanceKlass::mark_dependent_nmethods(DeoptimizationScope* deopt_scope, KlassDepChange& changes) {
2659   dependencies().mark_dependent_nmethods(deopt_scope, changes, this);
2660 }
2661 
2662 void InstanceKlass::add_dependent_nmethod(nmethod* nm) {
2663   assert_lock_strong(CodeCache_lock);
2664   dependencies().add_dependent_nmethod(nm);
2665 }
2666 
2667 void InstanceKlass::clean_dependency_context() {
2668   dependencies().clean_unloading_dependents();
2669 }
2670 
2671 #ifndef PRODUCT
2672 void InstanceKlass::print_dependent_nmethods(bool verbose) {
2673   dependencies().print_dependent_nmethods(verbose);
2674 }
2675 
2676 bool InstanceKlass::is_dependent_nmethod(nmethod* nm) {
2677   return dependencies().is_dependent_nmethod(nm);
2678 }
2679 #endif //PRODUCT
2680 
2681 void InstanceKlass::clean_weak_instanceklass_links() {
2682   clean_implementors_list();
2683   clean_method_data();
2684 }
2685 
2686 void InstanceKlass::clean_implementors_list() {
2687   assert(is_loader_alive(), "this klass should be live");
2688   if (is_interface()) {
2689     assert (ClassUnloading, "only called for ClassUnloading");
2690     for (;;) {
2691       // Use load_acquire due to competing with inserts
2692       InstanceKlass* volatile* iklass = adr_implementor();
2693       assert(iklass != nullptr, "Klass must not be null");
2694       InstanceKlass* impl = AtomicAccess::load_acquire(iklass);
2695       if (impl != nullptr && !impl->is_loader_alive()) {
2696         // null this field, might be an unloaded instance klass or null
2697         if (AtomicAccess::cmpxchg(iklass, impl, (InstanceKlass*)nullptr) == impl) {
2698           // Successfully unlinking implementor.
2699           if (log_is_enabled(Trace, class, unload)) {
2700             ResourceMark rm;
2701             log_trace(class, unload)("unlinking class (implementor): %s", impl->external_name());
2702           }
2703           return;
2704         }
2705       } else {
2706         return;
2707       }
2708     }
2709   }
2710 }
2711 
2712 void InstanceKlass::clean_method_data() {
2713   for (int m = 0; m < methods()->length(); m++) {
2714     MethodData* mdo = methods()->at(m)->method_data();
2715     if (mdo != nullptr) {
2716       mdo->clean_method_data(/*always_clean*/false);
2717     }
2718   }
2719 }
2720 
2721 void InstanceKlass::metaspace_pointers_do(MetaspaceClosure* it) {
2722   Klass::metaspace_pointers_do(it);
2723 
2724   if (log_is_enabled(Trace, aot)) {
2725     ResourceMark rm;
2726     log_trace(aot)("Iter(InstanceKlass): %p (%s)", this, external_name());
2727   }
2728 
2729   it->push(&_annotations);
2730   it->push((Klass**)&_array_klasses);
2731   if (!is_rewritten()) {
2732     it->push(&_constants, MetaspaceClosure::_writable);
2733   } else {
2734     it->push(&_constants);
2735   }
2736   it->push(&_inner_classes);
2737 #if INCLUDE_JVMTI
2738   it->push(&_previous_versions);
2739 #endif
2740 #if INCLUDE_CDS
2741   // For "old" classes with methods containing the jsr bytecode, the _methods array will
2742   // be rewritten during runtime (see Rewriter::rewrite_jsrs()) but they cannot be safely
2743   // checked here with ByteCodeStream. All methods that can't be verified are made writable.
2744   // The length check on the _methods is necessary because classes which don't have any
2745   // methods share the Universe::_the_empty_method_array which is in the RO region.
2746   if (_methods != nullptr && _methods->length() > 0 && !can_be_verified_at_dumptime()) {
2747     // To handle jsr bytecode, new Method* maybe stored into _methods
2748     it->push(&_methods, MetaspaceClosure::_writable);
2749   } else {
2750 #endif
2751     it->push(&_methods);
2752 #if INCLUDE_CDS
2753   }
2754 #endif
2755   it->push(&_default_methods);
2756   it->push(&_local_interfaces);
2757   it->push(&_transitive_interfaces);
2758   it->push(&_method_ordering);
2759   if (!is_rewritten()) {
2760     it->push(&_default_vtable_indices, MetaspaceClosure::_writable);
2761   } else {
2762     it->push(&_default_vtable_indices);
2763   }
2764 
2765   it->push(&_fieldinfo_stream);
2766   it->push(&_fieldinfo_search_table);
2767   // _fields_status might be written into by Rewriter::scan_method() -> fd.set_has_initialized_final_update()
2768   it->push(&_fields_status, MetaspaceClosure::_writable);
2769 
2770   if (itable_length() > 0) {
2771     itableOffsetEntry* ioe = (itableOffsetEntry*)start_of_itable();
2772     int method_table_offset_in_words = ioe->offset()/wordSize;
2773     int itable_offset_in_words = (int)(start_of_itable() - (intptr_t*)this);
2774 
2775     int nof_interfaces = (method_table_offset_in_words - itable_offset_in_words)
2776                          / itableOffsetEntry::size();
2777 
2778     for (int i = 0; i < nof_interfaces; i ++, ioe ++) {
2779       if (ioe->interface_klass() != nullptr) {
2780         it->push(ioe->interface_klass_addr());
2781         itableMethodEntry* ime = ioe->first_method_entry(this);
2782         int n = klassItable::method_count_for_interface(ioe->interface_klass());
2783         for (int index = 0; index < n; index ++) {
2784           it->push(ime[index].method_addr());
2785         }
2786       }
2787     }
2788   }
2789 
2790   it->push(&_nest_host);
2791   it->push(&_nest_members);
2792   it->push(&_permitted_subclasses);
2793   it->push(&_record_components);
2794 
2795   if (CDSConfig::is_dumping_full_module_graph() && !defined_by_other_loaders()) {
2796     it->push(&_package_entry);
2797   }
2798 }
2799 
2800 #if INCLUDE_CDS
2801 void InstanceKlass::remove_unshareable_info() {
2802 
2803   if (is_linked()) {
2804     assert(can_be_verified_at_dumptime(), "must be");
2805     // Remember this so we can avoid walking the hierarchy at runtime.
2806     set_verified_at_dump_time();
2807   }
2808 
2809   _misc_flags.set_has_init_deps_processed(false);
2810 
2811   Klass::remove_unshareable_info();
2812 
2813   if (SystemDictionaryShared::has_class_failed_verification(this)) {
2814     // Classes are attempted to link during dumping and may fail,
2815     // but these classes are still in the dictionary and class list in CLD.
2816     // If the class has failed verification, there is nothing else to remove.
2817     return;
2818   }
2819 
2820   // Reset to the 'allocated' state to prevent any premature accessing to
2821   // a shared class at runtime while the class is still being loaded and
2822   // restored. A class' init_state is set to 'loaded' at runtime when it's
2823   // being added to class hierarchy (see InstanceKlass:::add_to_hierarchy()).
2824   _init_state = allocated;
2825 
2826   { // Otherwise this needs to take out the Compile_lock.
2827     assert(SafepointSynchronize::is_at_safepoint(), "only called at safepoint");
2828     init_implementor();
2829   }
2830 
2831   // Call remove_unshareable_info() on other objects that belong to this class, except
2832   // for constants()->remove_unshareable_info(), which is called in a separate pass in
2833   // ArchiveBuilder::make_klasses_shareable(),
2834 
2835   for (int i = 0; i < methods()->length(); i++) {
2836     Method* m = methods()->at(i);
2837     m->remove_unshareable_info();
2838   }
2839 
2840   // do array classes also.
2841   if (array_klasses() != nullptr) {
2842     array_klasses()->remove_unshareable_info();
2843   }
2844 
2845   // These are not allocated from metaspace. They are safe to set to null.
2846   _source_debug_extension = nullptr;
2847   _dep_context = nullptr;
2848   _osr_nmethods_head = nullptr;
2849 #if INCLUDE_JVMTI
2850   _breakpoints = nullptr;
2851   _previous_versions = nullptr;
2852   _cached_class_file = nullptr;
2853   _jvmti_cached_class_field_map = nullptr;
2854 #endif
2855 
2856   _init_thread = nullptr;
2857   _methods_jmethod_ids = nullptr;
2858   _jni_ids = nullptr;
2859   _oop_map_cache = nullptr;
2860   if (CDSConfig::is_dumping_method_handles() && HeapShared::is_lambda_proxy_klass(this)) {
2861     // keep _nest_host
2862   } else {
2863     // clear _nest_host to ensure re-load at runtime
2864     _nest_host = nullptr;
2865   }
2866   init_shared_package_entry();
2867   _dep_context_last_cleaned = 0;
2868   DEBUG_ONLY(_shared_class_load_count = 0);
2869 
2870   remove_unshareable_flags();
2871 
2872   DEBUG_ONLY(FieldInfoStream::validate_search_table(_constants, _fieldinfo_stream, _fieldinfo_search_table));
2873 }
2874 
2875 void InstanceKlass::remove_unshareable_flags() {
2876   // clear all the flags/stats that shouldn't be in the archived version
2877   assert(!is_scratch_class(), "must be");
2878   assert(!has_been_redefined(), "must be");
2879 #if INCLUDE_JVMTI
2880   set_is_being_redefined(false);
2881 #endif
2882   set_has_resolved_methods(false);
2883 }
2884 
2885 void InstanceKlass::remove_java_mirror() {
2886   Klass::remove_java_mirror();
2887 
2888   // do array classes also.
2889   if (array_klasses() != nullptr) {
2890     array_klasses()->remove_java_mirror();
2891   }
2892 }
2893 
2894 void InstanceKlass::init_shared_package_entry() {
2895   assert(CDSConfig::is_dumping_archive(), "must be");
2896   if (!CDSConfig::is_dumping_full_module_graph() || defined_by_other_loaders()) {
2897     _package_entry = nullptr;
2898   }
2899 }
2900 
2901 void InstanceKlass::compute_has_loops_flag_for_methods() {
2902   Array<Method*>* methods = this->methods();
2903   for (int index = 0; index < methods->length(); ++index) {
2904     Method* m = methods->at(index);
2905     if (!m->is_overpass()) { // work around JDK-8305771
2906       m->compute_has_loops_flag();
2907     }
2908   }
2909 }
2910 
2911 void InstanceKlass::restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain,
2912                                              PackageEntry* pkg_entry, TRAPS) {
2913   // InstanceKlass::add_to_hierarchy() sets the init_state to loaded
2914   // before the InstanceKlass is added to the SystemDictionary. Make
2915   // sure the current state is <loaded.
2916   assert(!is_loaded(), "invalid init state");
2917   assert(!shared_loading_failed(), "Must not try to load failed class again");
2918   set_package(loader_data, pkg_entry, CHECK);
2919   Klass::restore_unshareable_info(loader_data, protection_domain, CHECK);
2920 
2921   Array<Method*>* methods = this->methods();
2922   int num_methods = methods->length();
2923   for (int index = 0; index < num_methods; ++index) {
2924     methods->at(index)->restore_unshareable_info(CHECK);
2925   }
2926 #if INCLUDE_JVMTI
2927   if (JvmtiExport::has_redefined_a_class()) {
2928     // Reinitialize vtable because RedefineClasses may have changed some
2929     // entries in this vtable for super classes so the CDS vtable might
2930     // point to old or obsolete entries.  RedefineClasses doesn't fix up
2931     // vtables in the shared system dictionary, only the main one.
2932     // It also redefines the itable too so fix that too.
2933     // First fix any default methods that point to a super class that may
2934     // have been redefined.
2935     bool trace_name_printed = false;
2936     adjust_default_methods(&trace_name_printed);
2937     if (verified_at_dump_time()) {
2938       // Initialize vtable and itable for classes which can be verified at dump time.
2939       // Unlinked classes such as old classes with major version < 50 cannot be verified
2940       // at dump time.
2941       vtable().initialize_vtable();
2942       itable().initialize_itable();
2943     }
2944   }
2945 #endif // INCLUDE_JVMTI
2946 
2947   // restore constant pool resolved references
2948   constants()->restore_unshareable_info(CHECK);
2949 
2950   if (array_klasses() != nullptr) {
2951     // To get a consistent list of classes we need MultiArray_lock to ensure
2952     // array classes aren't observed while they are being restored.
2953     RecursiveLocker rl(MultiArray_lock, THREAD);
2954     assert(this == array_klasses()->bottom_klass(), "sanity");
2955     // Array classes have null protection domain.
2956     // --> see ArrayKlass::complete_create_array_klass()
2957     array_klasses()->restore_unshareable_info(class_loader_data(), Handle(), CHECK);
2958   }
2959 
2960   // Initialize @ValueBased class annotation if not already set in the archived klass.
2961   if (DiagnoseSyncOnValueBasedClasses && has_value_based_class_annotation() && !is_value_based()) {
2962     set_is_value_based();
2963   }
2964 
2965   DEBUG_ONLY(FieldInfoStream::validate_search_table(_constants, _fieldinfo_stream, _fieldinfo_search_table));
2966 }
2967 
2968 bool InstanceKlass::can_be_verified_at_dumptime() const {
2969   if (CDSConfig::is_dumping_dynamic_archive() && AOTMetaspace::in_aot_cache(this)) {
2970     // This is a class that was dumped into the base archive, so we know
2971     // it was verified at dump time.
2972     return true;
2973   }
2974 
2975   if (CDSConfig::is_preserving_verification_constraints()) {
2976     return true;
2977   }
2978 
2979   if (CDSConfig::is_old_class_for_verifier(this)) {
2980     // The old verifier does not save verification constraints, so at run time
2981     // SystemDictionaryShared::check_verification_constraints() will not work for this class.
2982     return false;
2983   }
2984   if (super() != nullptr && !super()->can_be_verified_at_dumptime()) {
2985     return false;
2986   }
2987   Array<InstanceKlass*>* interfaces = local_interfaces();
2988   int len = interfaces->length();
2989   for (int i = 0; i < len; i++) {
2990     if (!interfaces->at(i)->can_be_verified_at_dumptime()) {
2991       return false;
2992     }
2993   }
2994   return true;
2995 }
2996 
2997 #endif // INCLUDE_CDS
2998 
2999 #if INCLUDE_JVMTI
3000 static void clear_all_breakpoints(Method* m) {
3001   m->clear_all_breakpoints();
3002 }
3003 #endif
3004 
3005 void InstanceKlass::unload_class(InstanceKlass* ik) {
3006 
3007   if (ik->is_scratch_class()) {
3008     assert(ik->dependencies().is_empty(), "dependencies should be empty for scratch classes");
3009     return;
3010   }
3011   assert(ik->is_loaded(), "class should be loaded " PTR_FORMAT, p2i(ik));
3012 
3013   // Release dependencies.
3014   ik->dependencies().remove_all_dependents();
3015 
3016   // notify the debugger
3017   if (JvmtiExport::should_post_class_unload()) {
3018     JvmtiExport::post_class_unload(ik);
3019   }
3020 
3021   // notify ClassLoadingService of class unload
3022   ClassLoadingService::notify_class_unloaded(ik);
3023 
3024   SystemDictionaryShared::handle_class_unloading(ik);
3025 
3026   if (log_is_enabled(Info, class, unload)) {
3027     ResourceMark rm;
3028     log_info(class, unload)("unloading class %s " PTR_FORMAT, ik->external_name(), p2i(ik));
3029   }
3030 
3031   Events::log_class_unloading(Thread::current(), ik);
3032 
3033 #if INCLUDE_JFR
3034   assert(ik != nullptr, "invariant");
3035   EventClassUnload event;
3036   event.set_unloadedClass(ik);
3037   event.set_definingClassLoader(ik->class_loader_data());
3038   event.commit();
3039 #endif
3040 }
3041 
3042 static void method_release_C_heap_structures(Method* m) {
3043   m->release_C_heap_structures();
3044 }
3045 
3046 // Called also by InstanceKlass::deallocate_contents, with false for release_sub_metadata.
3047 void InstanceKlass::release_C_heap_structures(bool release_sub_metadata) {
3048   // Clean up C heap
3049   Klass::release_C_heap_structures();
3050 
3051   // Deallocate and call destructors for MDO mutexes
3052   if (release_sub_metadata) {
3053     methods_do(method_release_C_heap_structures);
3054   }
3055 
3056   // Deallocate oop map cache
3057   if (_oop_map_cache != nullptr) {
3058     delete _oop_map_cache;
3059     _oop_map_cache = nullptr;
3060   }
3061 
3062   // Deallocate JNI identifiers for jfieldIDs
3063   JNIid::deallocate(jni_ids());
3064   set_jni_ids(nullptr);
3065 
3066   jmethodID* jmeths = _methods_jmethod_ids;
3067   if (jmeths != nullptr) {
3068     release_set_methods_jmethod_ids(nullptr);
3069     FreeHeap(jmeths);
3070   }
3071 
3072   assert(_dep_context == nullptr,
3073          "dependencies should already be cleaned");
3074 
3075 #if INCLUDE_JVMTI
3076   // Deallocate breakpoint records
3077   if (breakpoints() != nullptr) {
3078     methods_do(clear_all_breakpoints);
3079     assert(breakpoints() == nullptr, "should have cleared breakpoints");
3080   }
3081 
3082   // deallocate the cached class file
3083   if (_cached_class_file != nullptr) {
3084     os::free(_cached_class_file);
3085     _cached_class_file = nullptr;
3086   }
3087 #endif
3088 
3089   FREE_C_HEAP_ARRAY(char, _source_debug_extension);
3090 
3091   if (release_sub_metadata) {
3092     constants()->release_C_heap_structures();
3093   }
3094 }
3095 
3096 // The constant pool is on stack if any of the methods are executing or
3097 // referenced by handles.
3098 bool InstanceKlass::on_stack() const {
3099   return _constants->on_stack();
3100 }
3101 
3102 Symbol* InstanceKlass::source_file_name() const               { return _constants->source_file_name(); }
3103 u2 InstanceKlass::source_file_name_index() const              { return _constants->source_file_name_index(); }
3104 void InstanceKlass::set_source_file_name_index(u2 sourcefile_index) { _constants->set_source_file_name_index(sourcefile_index); }
3105 
3106 // minor and major version numbers of class file
3107 u2 InstanceKlass::minor_version() const                 { return _constants->minor_version(); }
3108 void InstanceKlass::set_minor_version(u2 minor_version) { _constants->set_minor_version(minor_version); }
3109 u2 InstanceKlass::major_version() const                 { return _constants->major_version(); }
3110 void InstanceKlass::set_major_version(u2 major_version) { _constants->set_major_version(major_version); }
3111 
3112 const InstanceKlass* InstanceKlass::get_klass_version(int version) const {
3113   for (const InstanceKlass* ik = this; ik != nullptr; ik = ik->previous_versions()) {
3114     if (ik->constants()->version() == version) {
3115       return ik;
3116     }
3117   }
3118   return nullptr;
3119 }
3120 
3121 void InstanceKlass::set_source_debug_extension(const char* array, int length) {
3122   if (array == nullptr) {
3123     _source_debug_extension = nullptr;
3124   } else {
3125     // Adding one to the attribute length in order to store a null terminator
3126     // character could cause an overflow because the attribute length is
3127     // already coded with an u4 in the classfile, but in practice, it's
3128     // unlikely to happen.
3129     assert((length+1) > length, "Overflow checking");
3130     char* sde = NEW_C_HEAP_ARRAY(char, (length + 1), mtClass);
3131     for (int i = 0; i < length; i++) {
3132       sde[i] = array[i];
3133     }
3134     sde[length] = '\0';
3135     _source_debug_extension = sde;
3136   }
3137 }
3138 
3139 Symbol* InstanceKlass::generic_signature() const                   { return _constants->generic_signature(); }
3140 u2 InstanceKlass::generic_signature_index() const                  { return _constants->generic_signature_index(); }
3141 void InstanceKlass::set_generic_signature_index(u2 sig_index)      { _constants->set_generic_signature_index(sig_index); }
3142 
3143 const char* InstanceKlass::signature_name() const {
3144 
3145   // Get the internal name as a c string
3146   const char* src = (const char*) (name()->as_C_string());
3147   const int src_length = (int)strlen(src);
3148 
3149   char* dest = NEW_RESOURCE_ARRAY(char, src_length + 3);
3150 
3151   // Add L as type indicator
3152   int dest_index = 0;
3153   dest[dest_index++] = JVM_SIGNATURE_CLASS;
3154 
3155   // Add the actual class name
3156   for (int src_index = 0; src_index < src_length; ) {
3157     dest[dest_index++] = src[src_index++];
3158   }
3159 
3160   if (is_hidden()) { // Replace the last '+' with a '.'.
3161     for (int index = (int)src_length; index > 0; index--) {
3162       if (dest[index] == '+') {
3163         dest[index] = JVM_SIGNATURE_DOT;
3164         break;
3165       }
3166     }
3167   }
3168 
3169   // Add the semicolon and the null
3170   dest[dest_index++] = JVM_SIGNATURE_ENDCLASS;
3171   dest[dest_index] = '\0';
3172   return dest;
3173 }
3174 
3175 ModuleEntry* InstanceKlass::module() const {
3176   if (is_hidden() &&
3177       in_unnamed_package() &&
3178       class_loader_data()->has_class_mirror_holder()) {
3179     // For a non-strong hidden class defined to an unnamed package,
3180     // its (class held) CLD will not have an unnamed module created for it.
3181     // Two choices to find the correct ModuleEntry:
3182     // 1. If hidden class is within a nest, use nest host's module
3183     // 2. Find the unnamed module off from the class loader
3184     // For now option #2 is used since a nest host is not set until
3185     // after the instance class is created in jvm_lookup_define_class().
3186     if (class_loader_data()->is_boot_class_loader_data()) {
3187       return ClassLoaderData::the_null_class_loader_data()->unnamed_module();
3188     } else {
3189       oop module = java_lang_ClassLoader::unnamedModule(class_loader_data()->class_loader());
3190       assert(java_lang_Module::is_instance(module), "Not an instance of java.lang.Module");
3191       return java_lang_Module::module_entry(module);
3192     }
3193   }
3194 
3195   // Class is in a named package
3196   if (!in_unnamed_package()) {
3197     return _package_entry->module();
3198   }
3199 
3200   // Class is in an unnamed package, return its loader's unnamed module
3201   return class_loader_data()->unnamed_module();
3202 }
3203 
3204 bool InstanceKlass::in_javabase_module() const {
3205   return module()->name() == vmSymbols::java_base();
3206 }
3207 
3208 void InstanceKlass::set_package(ClassLoaderData* loader_data, PackageEntry* pkg_entry, TRAPS) {
3209 
3210   // ensure java/ packages only loaded by boot or platform builtin loaders
3211   // not needed for shared class since CDS does not archive prohibited classes.
3212   if (!in_aot_cache()) {
3213     check_prohibited_package(name(), loader_data, CHECK);
3214   }
3215 
3216   if (in_aot_cache() && _package_entry != nullptr) {
3217     if (CDSConfig::is_using_full_module_graph() && _package_entry == pkg_entry) {
3218       // we can use the saved package
3219       assert(AOTMetaspace::in_aot_cache(_package_entry), "must be");
3220       return;
3221     } else {
3222       _package_entry = nullptr;
3223     }
3224   }
3225 
3226   // ClassLoader::package_from_class_name has already incremented the refcount of the symbol
3227   // it returns, so we need to decrement it when the current function exits.
3228   TempNewSymbol from_class_name =
3229       (pkg_entry != nullptr) ? nullptr : ClassLoader::package_from_class_name(name());
3230 
3231   Symbol* pkg_name;
3232   if (pkg_entry != nullptr) {
3233     pkg_name = pkg_entry->name();
3234   } else {
3235     pkg_name = from_class_name;
3236   }
3237 
3238   if (pkg_name != nullptr && loader_data != nullptr) {
3239 
3240     // Find in class loader's package entry table.
3241     _package_entry = pkg_entry != nullptr ? pkg_entry : loader_data->packages()->lookup_only(pkg_name);
3242 
3243     // If the package name is not found in the loader's package
3244     // entry table, it is an indication that the package has not
3245     // been defined. Consider it defined within the unnamed module.
3246     if (_package_entry == nullptr) {
3247 
3248       if (!ModuleEntryTable::javabase_defined()) {
3249         // Before java.base is defined during bootstrapping, define all packages in
3250         // the java.base module.  If a non-java.base package is erroneously placed
3251         // in the java.base module it will be caught later when java.base
3252         // is defined by ModuleEntryTable::verify_javabase_packages check.
3253         assert(ModuleEntryTable::javabase_moduleEntry() != nullptr, JAVA_BASE_NAME " module is null");
3254         _package_entry = loader_data->packages()->create_entry_if_absent(pkg_name, ModuleEntryTable::javabase_moduleEntry());
3255       } else {
3256         assert(loader_data->unnamed_module() != nullptr, "unnamed module is null");
3257         _package_entry = loader_data->packages()->create_entry_if_absent(pkg_name, loader_data->unnamed_module());
3258       }
3259 
3260       // A package should have been successfully created
3261       DEBUG_ONLY(ResourceMark rm(THREAD));
3262       assert(_package_entry != nullptr, "Package entry for class %s not found, loader %s",
3263              name()->as_C_string(), loader_data->loader_name_and_id());
3264     }
3265 
3266     if (log_is_enabled(Debug, module)) {
3267       ResourceMark rm(THREAD);
3268       ModuleEntry* m = _package_entry->module();
3269       log_trace(module)("Setting package: class: %s, package: %s, loader: %s, module: %s",
3270                         external_name(),
3271                         pkg_name->as_C_string(),
3272                         loader_data->loader_name_and_id(),
3273                         (m->is_named() ? m->name()->as_C_string() : UNNAMED_MODULE));
3274     }
3275   } else {
3276     ResourceMark rm(THREAD);
3277     log_trace(module)("Setting package: class: %s, package: unnamed, loader: %s, module: %s",
3278                       external_name(),
3279                       (loader_data != nullptr) ? loader_data->loader_name_and_id() : "null",
3280                       UNNAMED_MODULE);
3281   }
3282 }
3283 
3284 // Function set_classpath_index ensures that for a non-null _package_entry
3285 // of the InstanceKlass, the entry is in the boot loader's package entry table.
3286 // It then sets the classpath_index in the package entry record.
3287 //
3288 // The classpath_index field is used to find the entry on the boot loader class
3289 // path for packages with classes loaded by the boot loader from -Xbootclasspath/a
3290 // in an unnamed module.  It is also used to indicate (for all packages whose
3291 // classes are loaded by the boot loader) that at least one of the package's
3292 // classes has been loaded.
3293 void InstanceKlass::set_classpath_index(s2 path_index) {
3294   if (_package_entry != nullptr) {
3295     DEBUG_ONLY(PackageEntryTable* pkg_entry_tbl = ClassLoaderData::the_null_class_loader_data()->packages();)
3296     assert(pkg_entry_tbl->lookup_only(_package_entry->name()) == _package_entry, "Should be same");
3297     assert(path_index != -1, "Unexpected classpath_index");
3298     _package_entry->set_classpath_index(path_index);
3299   }
3300 }
3301 
3302 // different versions of is_same_class_package
3303 
3304 bool InstanceKlass::is_same_class_package(const Klass* class2) const {
3305   oop classloader1 = this->class_loader();
3306   PackageEntry* classpkg1 = this->package();
3307   if (class2->is_objArray_klass()) {
3308     class2 = ObjArrayKlass::cast(class2)->bottom_klass();
3309   }
3310 
3311   oop classloader2;
3312   PackageEntry* classpkg2;
3313   if (class2->is_instance_klass()) {
3314     classloader2 = class2->class_loader();
3315     classpkg2 = class2->package();
3316   } else {
3317     assert(class2->is_typeArray_klass(), "should be type array");
3318     classloader2 = nullptr;
3319     classpkg2 = nullptr;
3320   }
3321 
3322   // Same package is determined by comparing class loader
3323   // and package entries. Both must be the same. This rule
3324   // applies even to classes that are defined in the unnamed
3325   // package, they still must have the same class loader.
3326   if ((classloader1 == classloader2) && (classpkg1 == classpkg2)) {
3327     return true;
3328   }
3329 
3330   return false;
3331 }
3332 
3333 // return true if this class and other_class are in the same package. Classloader
3334 // and classname information is enough to determine a class's package
3335 bool InstanceKlass::is_same_class_package(oop other_class_loader,
3336                                           const Symbol* other_class_name) const {
3337   if (class_loader() != other_class_loader) {
3338     return false;
3339   }
3340   if (name()->fast_compare(other_class_name) == 0) {
3341      return true;
3342   }
3343 
3344   {
3345     ResourceMark rm;
3346 
3347     bool bad_class_name = false;
3348     TempNewSymbol other_pkg = ClassLoader::package_from_class_name(other_class_name, &bad_class_name);
3349     if (bad_class_name) {
3350       return false;
3351     }
3352     // Check that package_from_class_name() returns null, not "", if there is no package.
3353     assert(other_pkg == nullptr || other_pkg->utf8_length() > 0, "package name is empty string");
3354 
3355     const Symbol* const this_package_name =
3356       this->package() != nullptr ? this->package()->name() : nullptr;
3357 
3358     if (this_package_name == nullptr || other_pkg == nullptr) {
3359       // One of the two doesn't have a package.  Only return true if the other
3360       // one also doesn't have a package.
3361       return this_package_name == other_pkg;
3362     }
3363 
3364     // Check if package is identical
3365     return this_package_name->fast_compare(other_pkg) == 0;
3366   }
3367 }
3368 
3369 static bool is_prohibited_package_slow(Symbol* class_name) {
3370   // Caller has ResourceMark
3371   int length;
3372   jchar* unicode = class_name->as_unicode(length);
3373   return (length >= 5 &&
3374           unicode[0] == 'j' &&
3375           unicode[1] == 'a' &&
3376           unicode[2] == 'v' &&
3377           unicode[3] == 'a' &&
3378           unicode[4] == '/');
3379 }
3380 
3381 // Only boot and platform class loaders can define classes in "java/" packages.
3382 void InstanceKlass::check_prohibited_package(Symbol* class_name,
3383                                              ClassLoaderData* loader_data,
3384                                              TRAPS) {
3385   if (!loader_data->is_boot_class_loader_data() &&
3386       !loader_data->is_platform_class_loader_data() &&
3387       class_name != nullptr && class_name->utf8_length() >= 5) {
3388     ResourceMark rm(THREAD);
3389     bool prohibited;
3390     const u1* base = class_name->base();
3391     if ((base[0] | base[1] | base[2] | base[3] | base[4]) & 0x80) {
3392       prohibited = is_prohibited_package_slow(class_name);
3393     } else {
3394       char* name = class_name->as_C_string();
3395       prohibited = (strncmp(name, JAVAPKG, JAVAPKG_LEN) == 0 && name[JAVAPKG_LEN] == '/');
3396     }
3397     if (prohibited) {
3398       TempNewSymbol pkg_name = ClassLoader::package_from_class_name(class_name);
3399       assert(pkg_name != nullptr, "Error in parsing package name starting with 'java/'");
3400       char* name = pkg_name->as_C_string();
3401       const char* class_loader_name = loader_data->loader_name_and_id();
3402       StringUtils::replace_no_expand(name, "/", ".");
3403       const char* msg_text1 = "Class loader (instance of): ";
3404       const char* msg_text2 = " tried to load prohibited package name: ";
3405       size_t len = strlen(msg_text1) + strlen(class_loader_name) + strlen(msg_text2) + strlen(name) + 1;
3406       char* message = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, len);
3407       jio_snprintf(message, len, "%s%s%s%s", msg_text1, class_loader_name, msg_text2, name);
3408       THROW_MSG(vmSymbols::java_lang_SecurityException(), message);
3409     }
3410   }
3411   return;
3412 }
3413 
3414 bool InstanceKlass::find_inner_classes_attr(int* ooff, int* noff, TRAPS) const {
3415   constantPoolHandle i_cp(THREAD, constants());
3416   for (InnerClassesIterator iter(this); !iter.done(); iter.next()) {
3417     int ioff = iter.inner_class_info_index();
3418     if (ioff != 0) {
3419       // Check to see if the name matches the class we're looking for
3420       // before attempting to find the class.
3421       if (i_cp->klass_name_at_matches(this, ioff)) {
3422         Klass* inner_klass = i_cp->klass_at(ioff, CHECK_false);
3423         if (this == inner_klass) {
3424           *ooff = iter.outer_class_info_index();
3425           *noff = iter.inner_name_index();
3426           return true;
3427         }
3428       }
3429     }
3430   }
3431   return false;
3432 }
3433 
3434 InstanceKlass* InstanceKlass::compute_enclosing_class(bool* inner_is_member, TRAPS) const {
3435   InstanceKlass* outer_klass = nullptr;
3436   *inner_is_member = false;
3437   int ooff = 0, noff = 0;
3438   bool has_inner_classes_attr = find_inner_classes_attr(&ooff, &noff, THREAD);
3439   if (has_inner_classes_attr) {
3440     constantPoolHandle i_cp(THREAD, constants());
3441     if (ooff != 0) {
3442       Klass* ok = i_cp->klass_at(ooff, CHECK_NULL);
3443       if (!ok->is_instance_klass()) {
3444         // If the outer class is not an instance klass then it cannot have
3445         // declared any inner classes.
3446         ResourceMark rm(THREAD);
3447         // Names are all known to be < 64k so we know this formatted message is not excessively large.
3448         Exceptions::fthrow(
3449           THREAD_AND_LOCATION,
3450           vmSymbols::java_lang_IncompatibleClassChangeError(),
3451           "%s and %s disagree on InnerClasses attribute",
3452           ok->external_name(),
3453           external_name());
3454         return nullptr;
3455       }
3456       outer_klass = InstanceKlass::cast(ok);
3457       *inner_is_member = true;
3458     }
3459     if (nullptr == outer_klass) {
3460       // It may be a local class; try for that.
3461       int encl_method_class_idx = enclosing_method_class_index();
3462       if (encl_method_class_idx != 0) {
3463         Klass* ok = i_cp->klass_at(encl_method_class_idx, CHECK_NULL);
3464         outer_klass = InstanceKlass::cast(ok);
3465         *inner_is_member = false;
3466       }
3467     }
3468   }
3469 
3470   // If no inner class attribute found for this class.
3471   if (nullptr == outer_klass) return nullptr;
3472 
3473   // Throws an exception if outer klass has not declared k as an inner klass
3474   // We need evidence that each klass knows about the other, or else
3475   // the system could allow a spoof of an inner class to gain access rights.
3476   Reflection::check_for_inner_class(outer_klass, this, *inner_is_member, CHECK_NULL);
3477   return outer_klass;
3478 }
3479 
3480 u2 InstanceKlass::compute_modifier_flags() const {
3481   u2 access = access_flags().as_unsigned_short();
3482 
3483   // But check if it happens to be member class.
3484   InnerClassesIterator iter(this);
3485   for (; !iter.done(); iter.next()) {
3486     int ioff = iter.inner_class_info_index();
3487     // Inner class attribute can be zero, skip it.
3488     // Strange but true:  JVM spec. allows null inner class refs.
3489     if (ioff == 0) continue;
3490 
3491     // only look at classes that are already loaded
3492     // since we are looking for the flags for our self.
3493     Symbol* inner_name = constants()->klass_name_at(ioff);
3494     if (name() == inner_name) {
3495       // This is really a member class.
3496       access = iter.inner_access_flags();
3497       break;
3498     }
3499   }
3500   // Remember to strip ACC_SUPER bit
3501   return (access & (~JVM_ACC_SUPER));
3502 }
3503 
3504 jint InstanceKlass::jvmti_class_status() const {
3505   jint result = 0;
3506 
3507   if (is_linked()) {
3508     result |= JVMTI_CLASS_STATUS_VERIFIED | JVMTI_CLASS_STATUS_PREPARED;
3509   }
3510 
3511   if (is_initialized()) {
3512     assert(is_linked(), "Class status is not consistent");
3513     result |= JVMTI_CLASS_STATUS_INITIALIZED;
3514   }
3515   if (is_in_error_state()) {
3516     result |= JVMTI_CLASS_STATUS_ERROR;
3517   }
3518   return result;
3519 }
3520 
3521 Method* InstanceKlass::method_at_itable(InstanceKlass* holder, int index, TRAPS) {
3522   bool implements_interface; // initialized by method_at_itable_or_null
3523   Method* m = method_at_itable_or_null(holder, index,
3524                                        implements_interface); // out parameter
3525   if (m != nullptr) {
3526     assert(implements_interface, "sanity");
3527     return m;
3528   } else if (implements_interface) {
3529     // Throw AbstractMethodError since corresponding itable slot is empty.
3530     THROW_NULL(vmSymbols::java_lang_AbstractMethodError());
3531   } else {
3532     // If the interface isn't implemented by the receiver class,
3533     // the VM should throw IncompatibleClassChangeError.
3534     ResourceMark rm(THREAD);
3535     stringStream ss;
3536     bool same_module = (module() == holder->module());
3537     ss.print("Receiver class %s does not implement "
3538              "the interface %s defining the method to be called "
3539              "(%s%s%s)",
3540              external_name(), holder->external_name(),
3541              (same_module) ? joint_in_module_of_loader(holder) : class_in_module_of_loader(),
3542              (same_module) ? "" : "; ",
3543              (same_module) ? "" : holder->class_in_module_of_loader());
3544     THROW_MSG_NULL(vmSymbols::java_lang_IncompatibleClassChangeError(), ss.as_string());
3545   }
3546 }
3547 
3548 Method* InstanceKlass::method_at_itable_or_null(InstanceKlass* holder, int index, bool& implements_interface) {
3549   klassItable itable(this);
3550   for (int i = 0; i < itable.size_offset_table(); i++) {
3551     itableOffsetEntry* offset_entry = itable.offset_entry(i);
3552     if (offset_entry->interface_klass() == holder) {
3553       implements_interface = true;
3554       itableMethodEntry* ime = offset_entry->first_method_entry(this);
3555       Method* m = ime[index].method();
3556       return m;
3557     }
3558   }
3559   implements_interface = false;
3560   return nullptr; // offset entry not found
3561 }
3562 
3563 int InstanceKlass::vtable_index_of_interface_method(Method* intf_method) {
3564   assert(is_linked(), "required");
3565   assert(intf_method->method_holder()->is_interface(), "not an interface method");
3566   assert(is_subtype_of(intf_method->method_holder()), "interface not implemented");
3567 
3568   int vtable_index = Method::invalid_vtable_index;
3569   Symbol* name = intf_method->name();
3570   Symbol* signature = intf_method->signature();
3571 
3572   // First check in default method array
3573   if (!intf_method->is_abstract() && default_methods() != nullptr) {
3574     int index = find_method_index(default_methods(),
3575                                   name, signature,
3576                                   Klass::OverpassLookupMode::find,
3577                                   Klass::StaticLookupMode::find,
3578                                   Klass::PrivateLookupMode::find);
3579     if (index >= 0) {
3580       vtable_index = default_vtable_indices()->at(index);
3581     }
3582   }
3583   if (vtable_index == Method::invalid_vtable_index) {
3584     // get vtable_index for miranda methods
3585     klassVtable vt = vtable();
3586     vtable_index = vt.index_of_miranda(name, signature);
3587   }
3588   return vtable_index;
3589 }
3590 
3591 #if INCLUDE_JVMTI
3592 // update default_methods for redefineclasses for methods that are
3593 // not yet in the vtable due to concurrent subclass define and superinterface
3594 // redefinition
3595 // Note: those in the vtable, should have been updated via adjust_method_entries
3596 void InstanceKlass::adjust_default_methods(bool* trace_name_printed) {
3597   // search the default_methods for uses of either obsolete or EMCP methods
3598   if (default_methods() != nullptr) {
3599     for (int index = 0; index < default_methods()->length(); index ++) {
3600       Method* old_method = default_methods()->at(index);
3601       if (old_method == nullptr || !old_method->is_old()) {
3602         continue; // skip uninteresting entries
3603       }
3604       assert(!old_method->is_deleted(), "default methods may not be deleted");
3605       Method* new_method = old_method->get_new_method();
3606       default_methods()->at_put(index, new_method);
3607 
3608       if (log_is_enabled(Info, redefine, class, update)) {
3609         ResourceMark rm;
3610         if (!(*trace_name_printed)) {
3611           log_info(redefine, class, update)
3612             ("adjust: klassname=%s default methods from name=%s",
3613              external_name(), old_method->method_holder()->external_name());
3614           *trace_name_printed = true;
3615         }
3616         log_debug(redefine, class, update, vtables)
3617           ("default method update: %s(%s) ",
3618            new_method->name()->as_C_string(), new_method->signature()->as_C_string());
3619       }
3620     }
3621   }
3622 }
3623 #endif // INCLUDE_JVMTI
3624 
3625 // On-stack replacement stuff
3626 void InstanceKlass::add_osr_nmethod(nmethod* n) {
3627   assert_lock_strong(NMethodState_lock);
3628 #ifndef PRODUCT
3629   nmethod* prev = lookup_osr_nmethod(n->method(), n->osr_entry_bci(), n->comp_level(), true);
3630   assert(prev == nullptr || !prev->is_in_use() COMPILER2_PRESENT(|| StressRecompilation),
3631       "redundant OSR recompilation detected. memory leak in CodeCache!");
3632 #endif
3633   // only one compilation can be active
3634   assert(n->is_osr_method(), "wrong kind of nmethod");
3635   n->set_osr_link(osr_nmethods_head());
3636   set_osr_nmethods_head(n);
3637   // Raise the highest osr level if necessary
3638   n->method()->set_highest_osr_comp_level(MAX2(n->method()->highest_osr_comp_level(), n->comp_level()));
3639 
3640   // Get rid of the osr methods for the same bci that have lower levels.
3641   for (int l = CompLevel_limited_profile; l < n->comp_level(); l++) {
3642     nmethod *inv = lookup_osr_nmethod(n->method(), n->osr_entry_bci(), l, true);
3643     if (inv != nullptr && inv->is_in_use()) {
3644       inv->make_not_entrant(nmethod::InvalidationReason::OSR_INVALIDATION_OF_LOWER_LEVEL);
3645     }
3646   }
3647 }
3648 
3649 // Remove osr nmethod from the list. Return true if found and removed.
3650 bool InstanceKlass::remove_osr_nmethod(nmethod* n) {
3651   // This is a short non-blocking critical region, so the no safepoint check is ok.
3652   ConditionalMutexLocker ml(NMethodState_lock, !NMethodState_lock->owned_by_self(), Mutex::_no_safepoint_check_flag);
3653   assert(n->is_osr_method(), "wrong kind of nmethod");
3654   nmethod* last = nullptr;
3655   nmethod* cur  = osr_nmethods_head();
3656   int max_level = CompLevel_none;  // Find the max comp level excluding n
3657   Method* m = n->method();
3658   // Search for match
3659   bool found = false;
3660   while(cur != nullptr && cur != n) {
3661     if (m == cur->method()) {
3662       // Find max level before n
3663       max_level = MAX2(max_level, cur->comp_level());
3664     }
3665     last = cur;
3666     cur = cur->osr_link();
3667   }
3668   nmethod* next = nullptr;
3669   if (cur == n) {
3670     found = true;
3671     next = cur->osr_link();
3672     if (last == nullptr) {
3673       // Remove first element
3674       set_osr_nmethods_head(next);
3675     } else {
3676       last->set_osr_link(next);
3677     }
3678   }
3679   n->set_osr_link(nullptr);
3680   cur = next;
3681   while (cur != nullptr) {
3682     // Find max level after n
3683     if (m == cur->method()) {
3684       max_level = MAX2(max_level, cur->comp_level());
3685     }
3686     cur = cur->osr_link();
3687   }
3688   m->set_highest_osr_comp_level(max_level);
3689   return found;
3690 }
3691 
3692 int InstanceKlass::mark_osr_nmethods(DeoptimizationScope* deopt_scope, const Method* m) {
3693   ConditionalMutexLocker ml(NMethodState_lock, !NMethodState_lock->owned_by_self(), Mutex::_no_safepoint_check_flag);
3694   nmethod* osr = osr_nmethods_head();
3695   int found = 0;
3696   while (osr != nullptr) {
3697     assert(osr->is_osr_method(), "wrong kind of nmethod found in chain");
3698     if (osr->method() == m) {
3699       deopt_scope->mark(osr);
3700       found++;
3701     }
3702     osr = osr->osr_link();
3703   }
3704   return found;
3705 }
3706 
3707 nmethod* InstanceKlass::lookup_osr_nmethod(const Method* m, int bci, int comp_level, bool match_level) const {
3708   ConditionalMutexLocker ml(NMethodState_lock, !NMethodState_lock->owned_by_self(), Mutex::_no_safepoint_check_flag);
3709   nmethod* osr = osr_nmethods_head();
3710   nmethod* best = nullptr;
3711   while (osr != nullptr) {
3712     assert(osr->is_osr_method(), "wrong kind of nmethod found in chain");
3713     // There can be a time when a c1 osr method exists but we are waiting
3714     // for a c2 version. When c2 completes its osr nmethod we will trash
3715     // the c1 version and only be able to find the c2 version. However
3716     // while we overflow in the c1 code at back branches we don't want to
3717     // try and switch to the same code as we are already running
3718 
3719     if (osr->method() == m &&
3720         (bci == InvocationEntryBci || osr->osr_entry_bci() == bci)) {
3721       if (match_level) {
3722         if (osr->comp_level() == comp_level) {
3723           // Found a match - return it.
3724           return osr;
3725         }
3726       } else {
3727         if (best == nullptr || (osr->comp_level() > best->comp_level())) {
3728           if (osr->comp_level() == CompilationPolicy::highest_compile_level()) {
3729             // Found the best possible - return it.
3730             return osr;
3731           }
3732           best = osr;
3733         }
3734       }
3735     }
3736     osr = osr->osr_link();
3737   }
3738 
3739   assert(match_level == false || best == nullptr, "shouldn't pick up anything if match_level is set");
3740   if (best != nullptr && best->comp_level() >= comp_level) {
3741     return best;
3742   }
3743   return nullptr;
3744 }
3745 
3746 // -----------------------------------------------------------------------------------------------------
3747 // Printing
3748 
3749 #define BULLET  " - "
3750 
3751 static const char* state_names[] = {
3752   "allocated", "loaded", "linked", "being_initialized", "fully_initialized", "initialization_error"
3753 };
3754 
3755 static void print_vtable(intptr_t* start, int len, outputStream* st) {
3756   for (int i = 0; i < len; i++) {
3757     intptr_t e = start[i];
3758     st->print("%d : " INTPTR_FORMAT, i, e);
3759     if (MetaspaceObj::is_valid((Metadata*)e)) {
3760       st->print(" ");
3761       ((Metadata*)e)->print_value_on(st);
3762     }
3763     st->cr();
3764   }
3765 }
3766 
3767 static void print_vtable(vtableEntry* start, int len, outputStream* st) {
3768   return print_vtable(reinterpret_cast<intptr_t*>(start), len, st);
3769 }
3770 
3771 const char* InstanceKlass::init_state_name() const {
3772   return state_names[init_state()];
3773 }
3774 
3775 const char* InstanceKlass::state2name(ClassState s) {
3776   return state_names[s];
3777 }
3778 
3779 void InstanceKlass::print_on(outputStream* st) const {
3780   assert(is_klass(), "must be klass");
3781   Klass::print_on(st);
3782 
3783   st->print(BULLET"instance size:     %d", size_helper());                        st->cr();
3784   st->print(BULLET"klass size:        %d", size());                               st->cr();
3785   st->print(BULLET"access:            "); access_flags().print_on(st);            st->cr();
3786   st->print(BULLET"flags:             "); _misc_flags.print_on(st);               st->cr();
3787   st->print(BULLET"state:             "); st->print_cr("%s", init_state_name());
3788   st->print(BULLET"name:              "); name()->print_value_on(st);             st->cr();
3789   st->print(BULLET"super:             "); Metadata::print_value_on_maybe_null(st, super()); st->cr();
3790   st->print(BULLET"sub:               ");
3791   Klass* sub = subklass();
3792   int n;
3793   for (n = 0; sub != nullptr; n++, sub = sub->next_sibling()) {
3794     if (n < MaxSubklassPrintSize) {
3795       sub->print_value_on(st);
3796       st->print("   ");
3797     }
3798   }
3799   if (n >= MaxSubklassPrintSize) st->print("(%zd more klasses...)", n - MaxSubklassPrintSize);
3800   st->cr();
3801 
3802   if (is_interface()) {
3803     st->print_cr(BULLET"nof implementors:  %d", nof_implementors());
3804     if (nof_implementors() == 1) {
3805       st->print_cr(BULLET"implementor:    ");
3806       st->print("   ");
3807       implementor()->print_value_on(st);
3808       st->cr();
3809     }
3810   }
3811 
3812   st->print(BULLET"arrays:            "); Metadata::print_value_on_maybe_null(st, array_klasses()); st->cr();
3813   st->print(BULLET"methods:           "); methods()->print_value_on(st);               st->cr();
3814   if (Verbose || WizardMode) {
3815     Array<Method*>* method_array = methods();
3816     for (int i = 0; i < method_array->length(); i++) {
3817       st->print("%d : ", i); method_array->at(i)->print_value(); st->cr();
3818     }
3819   }
3820   st->print(BULLET"method ordering:   "); method_ordering()->print_value_on(st);      st->cr();
3821   if (default_methods() != nullptr) {
3822     st->print(BULLET"default_methods:   "); default_methods()->print_value_on(st);    st->cr();
3823     if (Verbose) {
3824       Array<Method*>* method_array = default_methods();
3825       for (int i = 0; i < method_array->length(); i++) {
3826         st->print("%d : ", i); method_array->at(i)->print_value(); st->cr();
3827       }
3828     }
3829   }
3830   print_on_maybe_null(st, BULLET"default vtable indices:   ", default_vtable_indices());
3831   st->print(BULLET"local interfaces:  "); local_interfaces()->print_value_on(st);      st->cr();
3832   st->print(BULLET"trans. interfaces: "); transitive_interfaces()->print_value_on(st); st->cr();
3833 
3834   st->print(BULLET"secondary supers: "); secondary_supers()->print_value_on(st); st->cr();
3835 
3836   st->print(BULLET"hash_slot:         %d", hash_slot()); st->cr();
3837   st->print(BULLET"secondary bitmap: " UINTX_FORMAT_X_0, _secondary_supers_bitmap); st->cr();
3838 
3839   if (secondary_supers() != nullptr) {
3840     if (Verbose) {
3841       bool is_hashed = (_secondary_supers_bitmap != SECONDARY_SUPERS_BITMAP_FULL);
3842       st->print_cr(BULLET"---- secondary supers (%d words):", _secondary_supers->length());
3843       for (int i = 0; i < _secondary_supers->length(); i++) {
3844         ResourceMark rm; // for external_name()
3845         Klass* secondary_super = _secondary_supers->at(i);
3846         st->print(BULLET"%2d:", i);
3847         if (is_hashed) {
3848           int home_slot = compute_home_slot(secondary_super, _secondary_supers_bitmap);
3849           int distance = (i - home_slot) & SECONDARY_SUPERS_TABLE_MASK;
3850           st->print(" dist:%02d:", distance);
3851         }
3852         st->print_cr(" %p %s", secondary_super, secondary_super->external_name());
3853       }
3854     }
3855   }
3856   st->print(BULLET"constants:         "); constants()->print_value_on(st);         st->cr();
3857 
3858   print_on_maybe_null(st, BULLET"class loader data:  ", class_loader_data());
3859   print_on_maybe_null(st, BULLET"source file:       ", source_file_name());
3860   if (source_debug_extension() != nullptr) {
3861     st->print(BULLET"source debug extension:       ");
3862     st->print("%s", source_debug_extension());
3863     st->cr();
3864   }
3865   print_on_maybe_null(st, BULLET"class annotations:       ", class_annotations());
3866   print_on_maybe_null(st, BULLET"class type annotations:  ", class_type_annotations());
3867   print_on_maybe_null(st, BULLET"field annotations:       ", fields_annotations());
3868   print_on_maybe_null(st, BULLET"field type annotations:  ", fields_type_annotations());
3869   {
3870     bool have_pv = false;
3871     // previous versions are linked together through the InstanceKlass
3872     for (InstanceKlass* pv_node = previous_versions();
3873          pv_node != nullptr;
3874          pv_node = pv_node->previous_versions()) {
3875       if (!have_pv)
3876         st->print(BULLET"previous version:  ");
3877       have_pv = true;
3878       pv_node->constants()->print_value_on(st);
3879     }
3880     if (have_pv) st->cr();
3881   }
3882 
3883   print_on_maybe_null(st, BULLET"generic signature: ", generic_signature());
3884   st->print(BULLET"inner classes:     "); inner_classes()->print_value_on(st);     st->cr();
3885   st->print(BULLET"nest members:     "); nest_members()->print_value_on(st);     st->cr();
3886   print_on_maybe_null(st, BULLET"record components:     ", record_components());
3887   st->print(BULLET"permitted subclasses:     "); permitted_subclasses()->print_value_on(st);     st->cr();
3888   if (java_mirror() != nullptr) {
3889     st->print(BULLET"java mirror:       ");
3890     java_mirror()->print_value_on(st);
3891     st->cr();
3892   } else {
3893     st->print_cr(BULLET"java mirror:       null");
3894   }
3895   st->print(BULLET"vtable length      %d  (start addr: " PTR_FORMAT ")", vtable_length(), p2i(start_of_vtable())); st->cr();
3896   if (vtable_length() > 0 && (Verbose || WizardMode))  print_vtable(start_of_vtable(), vtable_length(), st);
3897   st->print(BULLET"itable length      %d (start addr: " PTR_FORMAT ")", itable_length(), p2i(start_of_itable())); st->cr();
3898   if (itable_length() > 0 && (Verbose || WizardMode))  print_vtable(start_of_itable(), itable_length(), st);
3899   st->print_cr(BULLET"---- static fields (%d words):", static_field_size());
3900 
3901   FieldPrinter print_static_field(st);
3902   ((InstanceKlass*)this)->do_local_static_fields(&print_static_field);
3903   st->print_cr(BULLET"---- non-static fields (%d words):", nonstatic_field_size());
3904   FieldPrinter print_nonstatic_field(st);
3905   InstanceKlass* ik = const_cast<InstanceKlass*>(this);
3906   ik->print_nonstatic_fields(&print_nonstatic_field);
3907 
3908   st->print(BULLET"non-static oop maps (%d entries): ", nonstatic_oop_map_count());
3909   OopMapBlock* map     = start_of_nonstatic_oop_maps();
3910   OopMapBlock* end_map = map + nonstatic_oop_map_count();
3911   while (map < end_map) {
3912     st->print("%d-%d ", map->offset(), map->offset() + heapOopSize*(map->count() - 1));
3913     map++;
3914   }
3915   st->cr();
3916 
3917   if (fieldinfo_search_table() != nullptr) {
3918     st->print_cr(BULLET"---- field info search table:");
3919     FieldInfoStream::print_search_table(st, _constants, _fieldinfo_stream, _fieldinfo_search_table);
3920   }
3921 }
3922 
3923 void InstanceKlass::print_value_on(outputStream* st) const {
3924   assert(is_klass(), "must be klass");
3925   if (Verbose || WizardMode)  access_flags().print_on(st);
3926   name()->print_value_on(st);
3927 }
3928 
3929 void FieldPrinter::do_field(fieldDescriptor* fd) {
3930   _st->print(BULLET);
3931    if (_obj == nullptr) {
3932      fd->print_on(_st);
3933      _st->cr();
3934    } else {
3935      fd->print_on_for(_st, _obj);
3936      _st->cr();
3937    }
3938 }
3939 
3940 
3941 void InstanceKlass::oop_print_on(oop obj, outputStream* st) {
3942   Klass::oop_print_on(obj, st);
3943 
3944   if (this == vmClasses::String_klass()) {
3945     typeArrayOop value  = java_lang_String::value(obj);
3946     juint        length = java_lang_String::length(obj);
3947     if (value != nullptr &&
3948         value->is_typeArray() &&
3949         length <= (juint) value->length()) {
3950       st->print(BULLET"string: ");
3951       java_lang_String::print(obj, st);
3952       st->cr();
3953     }
3954   }
3955 
3956   st->print_cr(BULLET"---- fields (total size %zu words):", oop_size(obj));
3957   FieldPrinter print_field(st, obj);
3958   print_nonstatic_fields(&print_field);
3959 
3960   if (this == vmClasses::Class_klass()) {
3961     st->print(BULLET"signature: ");
3962     java_lang_Class::print_signature(obj, st);
3963     st->cr();
3964     Klass* real_klass = java_lang_Class::as_Klass(obj);
3965     if (real_klass != nullptr && real_klass->is_instance_klass()) {
3966       st->print_cr(BULLET"---- static fields (%d):", java_lang_Class::static_oop_field_count(obj));
3967       InstanceKlass::cast(real_klass)->do_local_static_fields(&print_field);
3968     }
3969   } else if (this == vmClasses::MethodType_klass()) {
3970     st->print(BULLET"signature: ");
3971     java_lang_invoke_MethodType::print_signature(obj, st);
3972     st->cr();
3973   }
3974 }
3975 
3976 #ifndef PRODUCT
3977 
3978 bool InstanceKlass::verify_itable_index(int i) {
3979   int method_count = klassItable::method_count_for_interface(this);
3980   assert(i >= 0 && i < method_count, "index out of bounds");
3981   return true;
3982 }
3983 
3984 #endif //PRODUCT
3985 
3986 void InstanceKlass::oop_print_value_on(oop obj, outputStream* st) {
3987   st->print("a ");
3988   name()->print_value_on(st);
3989   obj->print_address_on(st);
3990   if (this == vmClasses::String_klass()
3991       && java_lang_String::value(obj) != nullptr) {
3992     ResourceMark rm;
3993     int len = java_lang_String::length(obj);
3994     int plen = (len < 24 ? len : 12);
3995     char* str = java_lang_String::as_utf8_string(obj, 0, plen);
3996     st->print(" = \"%s\"", str);
3997     if (len > plen)
3998       st->print("...[%d]", len);
3999   } else if (this == vmClasses::Class_klass()) {
4000     Klass* k = java_lang_Class::as_Klass(obj);
4001     st->print(" = ");
4002     if (k != nullptr) {
4003       k->print_value_on(st);
4004     } else {
4005       const char* tname = type2name(java_lang_Class::primitive_type(obj));
4006       st->print("%s", tname ? tname : "type?");
4007     }
4008   } else if (this == vmClasses::MethodType_klass()) {
4009     st->print(" = ");
4010     java_lang_invoke_MethodType::print_signature(obj, st);
4011   } else if (java_lang_boxing_object::is_instance(obj)) {
4012     st->print(" = ");
4013     java_lang_boxing_object::print(obj, st);
4014   } else if (this == vmClasses::LambdaForm_klass()) {
4015     oop vmentry = java_lang_invoke_LambdaForm::vmentry(obj);
4016     if (vmentry != nullptr) {
4017       st->print(" => ");
4018       vmentry->print_value_on(st);
4019     }
4020   } else if (this == vmClasses::MemberName_klass()) {
4021     Metadata* vmtarget = java_lang_invoke_MemberName::vmtarget(obj);
4022     if (vmtarget != nullptr) {
4023       st->print(" = ");
4024       vmtarget->print_value_on(st);
4025     } else {
4026       oop clazz = java_lang_invoke_MemberName::clazz(obj);
4027       oop name  = java_lang_invoke_MemberName::name(obj);
4028       if (clazz != nullptr) {
4029         clazz->print_value_on(st);
4030       } else {
4031         st->print("null");
4032       }
4033       st->print(".");
4034       if (name != nullptr) {
4035         name->print_value_on(st);
4036       } else {
4037         st->print("null");
4038       }
4039     }
4040   }
4041 }
4042 
4043 const char* InstanceKlass::internal_name() const {
4044   return external_name();
4045 }
4046 
4047 void InstanceKlass::print_class_load_logging(ClassLoaderData* loader_data,
4048                                              const ModuleEntry* module_entry,
4049                                              const ClassFileStream* cfs) const {
4050 
4051   if (ClassListWriter::is_enabled()) {
4052     ClassListWriter::write(this, cfs);
4053   }
4054 
4055   print_class_load_helper(loader_data, module_entry, cfs);
4056   print_class_load_cause_logging();
4057 }
4058 
4059 void InstanceKlass::print_class_load_helper(ClassLoaderData* loader_data,
4060                                              const ModuleEntry* module_entry,
4061                                              const ClassFileStream* cfs) const {
4062 
4063   if (!log_is_enabled(Info, class, load)) {
4064     return;
4065   }
4066 
4067   ResourceMark rm;
4068   LogMessage(class, load) msg;
4069   stringStream info_stream;
4070 
4071   // Name and class hierarchy info
4072   info_stream.print("%s", external_name());
4073 
4074   // Source
4075   if (cfs != nullptr) {
4076     if (cfs->source() != nullptr) {
4077       const char* module_name = (module_entry->name() == nullptr) ? UNNAMED_MODULE : module_entry->name()->as_C_string();
4078       if (module_name != nullptr) {
4079         // When the boot loader created the stream, it didn't know the module name
4080         // yet. Let's format it now.
4081         if (cfs->from_boot_loader_modules_image()) {
4082           info_stream.print(" source: jrt:/%s", module_name);
4083         } else {
4084           info_stream.print(" source: %s", cfs->source());
4085         }
4086       } else {
4087         info_stream.print(" source: %s", cfs->source());
4088       }
4089     } else if (loader_data == ClassLoaderData::the_null_class_loader_data()) {
4090       Thread* current = Thread::current();
4091       Klass* caller = current->is_Java_thread() ?
4092         JavaThread::cast(current)->security_get_caller_class(1):
4093         nullptr;
4094       // caller can be null, for example, during a JVMTI VM_Init hook
4095       if (caller != nullptr) {
4096         info_stream.print(" source: instance of %s", caller->external_name());
4097       } else {
4098         // source is unknown
4099       }
4100     } else {
4101       oop class_loader = loader_data->class_loader();
4102       info_stream.print(" source: %s", class_loader->klass()->external_name());
4103     }
4104   } else {
4105     assert(this->in_aot_cache(), "must be");
4106     if (AOTMetaspace::in_aot_cache_dynamic_region((void*)this)) {
4107       info_stream.print(" source: shared objects file (top)");
4108     } else {
4109       info_stream.print(" source: shared objects file");
4110     }
4111   }
4112 
4113   info_stream.print(" loader:");
4114 #if INCLUDE_CDS
4115   if (in_aot_cache()) {
4116     info_stream.print(" %s", SystemDictionaryShared::loader_type_for_shared_class((Klass*)this));
4117   } else
4118 #endif
4119   if (loader_data == ClassLoaderData::the_null_class_loader_data()) {
4120     info_stream.print(" boot_loader");
4121   } else {
4122     oop class_loader = loader_data->class_loader();
4123     if (class_loader != nullptr) {
4124       info_stream.print(" %s", class_loader->klass()->external_name());
4125       oop cl_name_and_id = java_lang_ClassLoader::nameAndId(class_loader);
4126       if (cl_name_and_id != nullptr) {
4127         info_stream.print(" %s", java_lang_String::as_utf8_string(cl_name_and_id));
4128       }
4129     } else {
4130       info_stream.print(" null");
4131     }
4132   }
4133   msg.info("%s", info_stream.as_string());
4134 
4135   if (log_is_enabled(Debug, class, load)) {
4136     stringStream debug_stream;
4137 
4138     // Class hierarchy info
4139     debug_stream.print(" klass: " PTR_FORMAT " super: " PTR_FORMAT,
4140                        p2i(this),  p2i(super()));
4141 
4142     // Interfaces
4143     if (local_interfaces() != nullptr && local_interfaces()->length() > 0) {
4144       debug_stream.print(" interfaces:");
4145       int length = local_interfaces()->length();
4146       for (int i = 0; i < length; i++) {
4147         debug_stream.print(" " PTR_FORMAT,
4148                            p2i(local_interfaces()->at(i)));
4149       }
4150     }
4151 
4152     // Class loader
4153     debug_stream.print(" loader: [");
4154     loader_data->print_value_on(&debug_stream);
4155     debug_stream.print("]");
4156 
4157     // Classfile checksum
4158     if (cfs) {
4159       debug_stream.print(" bytes: %d checksum: %08x",
4160                          cfs->length(),
4161                          ClassLoader::crc32(0, (const char*)cfs->buffer(),
4162                          cfs->length()));
4163     }
4164 
4165     msg.debug("%s", debug_stream.as_string());
4166   }
4167 }
4168 
4169 void InstanceKlass::print_class_load_cause_logging() const {
4170   bool log_cause_native = log_is_enabled(Info, class, load, cause, native);
4171   if (log_cause_native || log_is_enabled(Info, class, load, cause)) {
4172     JavaThread* current = JavaThread::current();
4173     ResourceMark rm(current);
4174     const char* name = external_name();
4175 
4176     if (LogClassLoadingCauseFor == nullptr ||
4177         (strcmp("*", LogClassLoadingCauseFor) != 0 &&
4178          strstr(name, LogClassLoadingCauseFor) == nullptr)) {
4179         return;
4180     }
4181 
4182     // Log Java stack first
4183     {
4184       LogMessage(class, load, cause) msg;
4185       NonInterleavingLogStream info_stream{LogLevelType::Info, msg};
4186 
4187       info_stream.print_cr("Java stack when loading %s:", name);
4188       current->print_stack_on(&info_stream);
4189     }
4190 
4191     // Log native stack second
4192     if (log_cause_native) {
4193       // Log to string first so that lines can be indented
4194       stringStream stack_stream;
4195       char buf[O_BUFLEN];
4196       address lastpc = nullptr;
4197       NativeStackPrinter nsp(current);
4198       nsp.print_stack(&stack_stream, buf, sizeof(buf), lastpc,
4199                       true /* print_source_info */, -1 /* max stack */);
4200 
4201       LogMessage(class, load, cause, native) msg;
4202       NonInterleavingLogStream info_stream{LogLevelType::Info, msg};
4203       info_stream.print_cr("Native stack when loading %s:", name);
4204 
4205       // Print each native stack line to the log
4206       int size = (int) stack_stream.size();
4207       char* stack = stack_stream.as_string();
4208       char* stack_end = stack + size;
4209       char* line_start = stack;
4210       for (char* p = stack; p < stack_end; p++) {
4211         if (*p == '\n') {
4212           *p = '\0';
4213           info_stream.print_cr("\t%s", line_start);
4214           line_start = p + 1;
4215         }
4216       }
4217       if (line_start < stack_end) {
4218         info_stream.print_cr("\t%s", line_start);
4219       }
4220     }
4221   }
4222 }
4223 
4224 // Verification
4225 
4226 class VerifyFieldClosure: public BasicOopIterateClosure {
4227  protected:
4228   template <class T> void do_oop_work(T* p) {
4229     oop obj = RawAccess<>::oop_load(p);
4230     if (!oopDesc::is_oop_or_null(obj)) {
4231       tty->print_cr("Failed: " PTR_FORMAT " -> " PTR_FORMAT, p2i(p), p2i(obj));
4232       Universe::print_on(tty);
4233       guarantee(false, "boom");
4234     }
4235   }
4236  public:
4237   virtual void do_oop(oop* p)       { VerifyFieldClosure::do_oop_work(p); }
4238   virtual void do_oop(narrowOop* p) { VerifyFieldClosure::do_oop_work(p); }
4239 };
4240 
4241 void InstanceKlass::verify_on(outputStream* st) {
4242 #ifndef PRODUCT
4243   // Avoid redundant verifies, this really should be in product.
4244   if (_verify_count == Universe::verify_count()) return;
4245   _verify_count = Universe::verify_count();
4246 #endif
4247 
4248   // Verify Klass
4249   Klass::verify_on(st);
4250 
4251   // Verify that klass is present in ClassLoaderData
4252   guarantee(class_loader_data()->contains_klass(this),
4253             "this class isn't found in class loader data");
4254 
4255   // Verify vtables
4256   if (is_linked()) {
4257     // $$$ This used to be done only for m/s collections.  Doing it
4258     // always seemed a valid generalization.  (DLD -- 6/00)
4259     vtable().verify(st);
4260   }
4261 
4262   // Verify first subklass
4263   if (subklass() != nullptr) {
4264     guarantee(subklass()->is_klass(), "should be klass");
4265   }
4266 
4267   // Verify siblings
4268   Klass* super = this->super();
4269   Klass* sib = next_sibling();
4270   if (sib != nullptr) {
4271     if (sib == this) {
4272       fatal("subclass points to itself " PTR_FORMAT, p2i(sib));
4273     }
4274 
4275     guarantee(sib->is_klass(), "should be klass");
4276     guarantee(sib->super() == super, "siblings should have same superklass");
4277   }
4278 
4279   // Verify local interfaces
4280   if (local_interfaces()) {
4281     Array<InstanceKlass*>* local_interfaces = this->local_interfaces();
4282     for (int j = 0; j < local_interfaces->length(); j++) {
4283       InstanceKlass* e = local_interfaces->at(j);
4284       guarantee(e->is_klass() && e->is_interface(), "invalid local interface");
4285     }
4286   }
4287 
4288   // Verify transitive interfaces
4289   if (transitive_interfaces() != nullptr) {
4290     Array<InstanceKlass*>* transitive_interfaces = this->transitive_interfaces();
4291     for (int j = 0; j < transitive_interfaces->length(); j++) {
4292       InstanceKlass* e = transitive_interfaces->at(j);
4293       guarantee(e->is_klass() && e->is_interface(), "invalid transitive interface");
4294     }
4295   }
4296 
4297   // Verify methods
4298   if (methods() != nullptr) {
4299     Array<Method*>* methods = this->methods();
4300     for (int j = 0; j < methods->length(); j++) {
4301       guarantee(methods->at(j)->is_method(), "non-method in methods array");
4302     }
4303     for (int j = 0; j < methods->length() - 1; j++) {
4304       Method* m1 = methods->at(j);
4305       Method* m2 = methods->at(j + 1);
4306       guarantee(m1->name()->fast_compare(m2->name()) <= 0, "methods not sorted correctly");
4307     }
4308   }
4309 
4310   // Verify method ordering
4311   if (method_ordering() != nullptr) {
4312     Array<int>* method_ordering = this->method_ordering();
4313     int length = method_ordering->length();
4314     if (JvmtiExport::can_maintain_original_method_order() ||
4315         ((CDSConfig::is_using_archive() || CDSConfig::is_dumping_archive()) && length != 0)) {
4316       guarantee(length == methods()->length(), "invalid method ordering length");
4317       jlong sum = 0;
4318       for (int j = 0; j < length; j++) {
4319         int original_index = method_ordering->at(j);
4320         guarantee(original_index >= 0, "invalid method ordering index");
4321         guarantee(original_index < length, "invalid method ordering index");
4322         sum += original_index;
4323       }
4324       // Verify sum of indices 0,1,...,length-1
4325       guarantee(sum == ((jlong)length*(length-1))/2, "invalid method ordering sum");
4326     } else {
4327       guarantee(length == 0, "invalid method ordering length");
4328     }
4329   }
4330 
4331   // Verify default methods
4332   if (default_methods() != nullptr) {
4333     Array<Method*>* methods = this->default_methods();
4334     for (int j = 0; j < methods->length(); j++) {
4335       guarantee(methods->at(j)->is_method(), "non-method in methods array");
4336     }
4337     for (int j = 0; j < methods->length() - 1; j++) {
4338       Method* m1 = methods->at(j);
4339       Method* m2 = methods->at(j + 1);
4340       guarantee(m1->name()->fast_compare(m2->name()) <= 0, "methods not sorted correctly");
4341     }
4342   }
4343 
4344   // Verify JNI static field identifiers
4345   if (jni_ids() != nullptr) {
4346     jni_ids()->verify(this);
4347   }
4348 
4349   // Verify other fields
4350   if (constants() != nullptr) {
4351     guarantee(constants()->is_constantPool(), "should be constant pool");
4352   }
4353 }
4354 
4355 void InstanceKlass::oop_verify_on(oop obj, outputStream* st) {
4356   Klass::oop_verify_on(obj, st);
4357   VerifyFieldClosure blk;
4358   obj->oop_iterate(&blk);
4359 }
4360 
4361 // JNIid class for jfieldIDs only
4362 // Note to reviewers:
4363 // These JNI functions are just moved over to column 1 and not changed
4364 // in the compressed oops workspace.
4365 JNIid::JNIid(InstanceKlass* holder, int offset, JNIid* next) {
4366   _holder = holder;
4367   _offset = offset;
4368   _next = next;
4369   DEBUG_ONLY(_is_static_field_id = false;)
4370 }
4371 
4372 JNIid* JNIid::find(int offset) {
4373   JNIid* current = this;
4374   while (current != nullptr) {
4375     if (current->offset() == offset) return current;
4376     current = current->next();
4377   }
4378   return nullptr;
4379 }
4380 
4381 void JNIid::deallocate(JNIid* current) {
4382   while (current != nullptr) {
4383     JNIid* next = current->next();
4384     delete current;
4385     current = next;
4386   }
4387 }
4388 
4389 void JNIid::verify(InstanceKlass* holder) {
4390   int first_field_offset  = InstanceMirrorKlass::offset_of_static_fields();
4391   int end_field_offset;
4392   end_field_offset = first_field_offset + (holder->static_field_size() * wordSize);
4393 
4394   JNIid* current = this;
4395   while (current != nullptr) {
4396     guarantee(current->holder() == holder, "Invalid klass in JNIid");
4397 #ifdef ASSERT
4398     int o = current->offset();
4399     if (current->is_static_field_id()) {
4400       guarantee(o >= first_field_offset  && o < end_field_offset,  "Invalid static field offset in JNIid");
4401     }
4402 #endif
4403     current = current->next();
4404   }
4405 }
4406 
4407 void InstanceKlass::set_init_state(ClassState state) {
4408 #ifdef ASSERT
4409   bool good_state = in_aot_cache() ? (_init_state <= state)
4410                                                : (_init_state < state);
4411   assert(good_state || state == allocated, "illegal state transition");
4412 #endif
4413   assert(_init_thread == nullptr, "should be cleared before state change");
4414   AtomicAccess::release_store(&_init_state, state);
4415 }
4416 
4417 #if INCLUDE_JVMTI
4418 
4419 // RedefineClasses() support for previous versions
4420 
4421 // Globally, there is at least one previous version of a class to walk
4422 // during class unloading, which is saved because old methods in the class
4423 // are still running.   Otherwise the previous version list is cleaned up.
4424 bool InstanceKlass::_should_clean_previous_versions = false;
4425 
4426 // Returns true if there are previous versions of a class for class
4427 // unloading only. Also resets the flag to false. purge_previous_version
4428 // will set the flag to true if there are any left, i.e., if there's any
4429 // work to do for next time. This is to avoid the expensive code cache
4430 // walk in CLDG::clean_deallocate_lists().
4431 bool InstanceKlass::should_clean_previous_versions_and_reset() {
4432   bool ret = _should_clean_previous_versions;
4433   log_trace(redefine, class, iklass, purge)("Class unloading: should_clean_previous_versions = %s",
4434      ret ? "true" : "false");
4435   _should_clean_previous_versions = false;
4436   return ret;
4437 }
4438 
4439 // This nulls out the jmethodID for all obsolete methods in the previous version of the 'klass'.
4440 // These obsolete methods only exist in the previous version and we're about to delete the memory for them.
4441 // The jmethodID for these are deallocated when we unload the class, so this doesn't remove them from the table.
4442 void InstanceKlass::clear_obsolete_jmethod_ids(InstanceKlass* klass) {
4443   Array<Method*>* method_refs = klass->methods();
4444   for (int k = 0; k < method_refs->length(); k++) {
4445     Method* method = method_refs->at(k);
4446     // Only need to clear obsolete methods.
4447     if (method != nullptr && method->is_obsolete()) {
4448       method->clear_jmethod_id();
4449     }
4450   }
4451 }
4452 
4453 // Purge previous versions before adding new previous versions of the class and
4454 // during class unloading.
4455 void InstanceKlass::purge_previous_version_list() {
4456   assert(SafepointSynchronize::is_at_safepoint(), "only called at safepoint");
4457   assert(has_been_redefined(), "Should only be called for main class");
4458 
4459   // Quick exit.
4460   if (previous_versions() == nullptr) {
4461     return;
4462   }
4463 
4464   // This klass has previous versions so see what we can cleanup
4465   // while it is safe to do so.
4466 
4467   int deleted_count = 0;    // leave debugging breadcrumbs
4468   int live_count = 0;
4469   ClassLoaderData* loader_data = class_loader_data();
4470   assert(loader_data != nullptr, "should never be null");
4471 
4472   ResourceMark rm;
4473   log_trace(redefine, class, iklass, purge)("%s: previous versions", external_name());
4474 
4475   // previous versions are linked together through the InstanceKlass
4476   InstanceKlass* pv_node = previous_versions();
4477   InstanceKlass* last = this;
4478   int version = 0;
4479 
4480   // check the previous versions list
4481   for (; pv_node != nullptr; ) {
4482 
4483     ConstantPool* pvcp = pv_node->constants();
4484     assert(pvcp != nullptr, "cp ref was unexpectedly cleared");
4485 
4486     if (!pvcp->on_stack()) {
4487       // If the constant pool isn't on stack, none of the methods
4488       // are executing.  Unlink this previous_version.
4489       // The previous version InstanceKlass is on the ClassLoaderData deallocate list
4490       // so will be deallocated during the next phase of class unloading.
4491       log_trace(redefine, class, iklass, purge)
4492         ("previous version " PTR_FORMAT " is dead.", p2i(pv_node));
4493       // Unlink from previous version list.
4494       assert(pv_node->class_loader_data() == loader_data, "wrong loader_data");
4495       InstanceKlass* next = pv_node->previous_versions();
4496       clear_obsolete_jmethod_ids(pv_node); // jmethodID maintenance for the unloaded class
4497       pv_node->link_previous_versions(nullptr);   // point next to null
4498       last->link_previous_versions(next);
4499       // Delete this node directly. Nothing is referring to it and we don't
4500       // want it to increase the counter for metadata to delete in CLDG.
4501       MetadataFactory::free_metadata(loader_data, pv_node);
4502       pv_node = next;
4503       deleted_count++;
4504       version++;
4505       continue;
4506     } else {
4507       assert(pvcp->pool_holder() != nullptr, "Constant pool with no holder");
4508       guarantee (!loader_data->is_unloading(), "unloaded classes can't be on the stack");
4509       live_count++;
4510       if (pvcp->in_aot_cache()) {
4511         // Shared previous versions can never be removed so no cleaning is needed.
4512         log_trace(redefine, class, iklass, purge)("previous version " PTR_FORMAT " is shared", p2i(pv_node));
4513       } else {
4514         // Previous version alive, set that clean is needed for next time.
4515         _should_clean_previous_versions = true;
4516         log_trace(redefine, class, iklass, purge)("previous version " PTR_FORMAT " is alive", p2i(pv_node));
4517       }
4518     }
4519 
4520     // next previous version
4521     last = pv_node;
4522     pv_node = pv_node->previous_versions();
4523     version++;
4524   }
4525   log_trace(redefine, class, iklass, purge)
4526     ("previous version stats: live=%d, deleted=%d", live_count, deleted_count);
4527 }
4528 
4529 void InstanceKlass::mark_newly_obsolete_methods(Array<Method*>* old_methods,
4530                                                 int emcp_method_count) {
4531   int obsolete_method_count = old_methods->length() - emcp_method_count;
4532 
4533   if (emcp_method_count != 0 && obsolete_method_count != 0 &&
4534       _previous_versions != nullptr) {
4535     // We have a mix of obsolete and EMCP methods so we have to
4536     // clear out any matching EMCP method entries the hard way.
4537     int local_count = 0;
4538     for (int i = 0; i < old_methods->length(); i++) {
4539       Method* old_method = old_methods->at(i);
4540       if (old_method->is_obsolete()) {
4541         // only obsolete methods are interesting
4542         Symbol* m_name = old_method->name();
4543         Symbol* m_signature = old_method->signature();
4544 
4545         // previous versions are linked together through the InstanceKlass
4546         int j = 0;
4547         for (InstanceKlass* prev_version = _previous_versions;
4548              prev_version != nullptr;
4549              prev_version = prev_version->previous_versions(), j++) {
4550 
4551           Array<Method*>* method_refs = prev_version->methods();
4552           for (int k = 0; k < method_refs->length(); k++) {
4553             Method* method = method_refs->at(k);
4554 
4555             if (!method->is_obsolete() &&
4556                 method->name() == m_name &&
4557                 method->signature() == m_signature) {
4558               // The current RedefineClasses() call has made all EMCP
4559               // versions of this method obsolete so mark it as obsolete
4560               log_trace(redefine, class, iklass, add)
4561                 ("%s(%s): flush obsolete method @%d in version @%d",
4562                  m_name->as_C_string(), m_signature->as_C_string(), k, j);
4563 
4564               method->set_is_obsolete();
4565               break;
4566             }
4567           }
4568 
4569           // The previous loop may not find a matching EMCP method, but
4570           // that doesn't mean that we can optimize and not go any
4571           // further back in the PreviousVersion generations. The EMCP
4572           // method for this generation could have already been made obsolete,
4573           // but there still may be an older EMCP method that has not
4574           // been made obsolete.
4575         }
4576 
4577         if (++local_count >= obsolete_method_count) {
4578           // no more obsolete methods so bail out now
4579           break;
4580         }
4581       }
4582     }
4583   }
4584 }
4585 
4586 // Save the scratch_class as the previous version if any of the methods are running.
4587 // The previous_versions are used to set breakpoints in EMCP methods and they are
4588 // also used to clean MethodData links to redefined methods that are no longer running.
4589 void InstanceKlass::add_previous_version(InstanceKlass* scratch_class,
4590                                          int emcp_method_count) {
4591   assert(Thread::current()->is_VM_thread(),
4592          "only VMThread can add previous versions");
4593 
4594   ResourceMark rm;
4595   log_trace(redefine, class, iklass, add)
4596     ("adding previous version ref for %s, EMCP_cnt=%d", scratch_class->external_name(), emcp_method_count);
4597 
4598   // Clean out old previous versions for this class
4599   purge_previous_version_list();
4600 
4601   // Mark newly obsolete methods in remaining previous versions.  An EMCP method from
4602   // a previous redefinition may be made obsolete by this redefinition.
4603   Array<Method*>* old_methods = scratch_class->methods();
4604   mark_newly_obsolete_methods(old_methods, emcp_method_count);
4605 
4606   // If the constant pool for this previous version of the class
4607   // is not marked as being on the stack, then none of the methods
4608   // in this previous version of the class are on the stack so
4609   // we don't need to add this as a previous version.
4610   ConstantPool* cp_ref = scratch_class->constants();
4611   if (!cp_ref->on_stack()) {
4612     log_trace(redefine, class, iklass, add)("scratch class not added; no methods are running");
4613     scratch_class->class_loader_data()->add_to_deallocate_list(scratch_class);
4614     return;
4615   }
4616 
4617   // Add previous version if any methods are still running or if this is
4618   // a shared class which should never be removed.
4619   assert(scratch_class->previous_versions() == nullptr, "shouldn't have a previous version");
4620   scratch_class->link_previous_versions(previous_versions());
4621   link_previous_versions(scratch_class);
4622   if (cp_ref->in_aot_cache()) {
4623     log_trace(redefine, class, iklass, add) ("scratch class added; class is shared");
4624   } else {
4625     //  We only set clean_previous_versions flag for processing during class
4626     // unloading for non-shared classes.
4627     _should_clean_previous_versions = true;
4628     log_trace(redefine, class, iklass, add) ("scratch class added; one of its methods is on_stack.");
4629   }
4630 } // end add_previous_version()
4631 
4632 #endif // INCLUDE_JVMTI
4633 
4634 Method* InstanceKlass::method_with_idnum(int idnum) const {
4635   Method* m = nullptr;
4636   if (idnum < methods()->length()) {
4637     m = methods()->at(idnum);
4638   }
4639   if (m == nullptr || m->method_idnum() != idnum) {
4640     for (int index = 0; index < methods()->length(); ++index) {
4641       m = methods()->at(index);
4642       if (m->method_idnum() == idnum) {
4643         return m;
4644       }
4645     }
4646     // None found, return null for the caller to handle.
4647     return nullptr;
4648   }
4649   return m;
4650 }
4651 
4652 
4653 Method* InstanceKlass::method_with_orig_idnum(int idnum) const {
4654   if (idnum >= methods()->length()) {
4655     return nullptr;
4656   }
4657   Method* m = methods()->at(idnum);
4658   if (m != nullptr && m->orig_method_idnum() == idnum) {
4659     return m;
4660   }
4661   // Obsolete method idnum does not match the original idnum
4662   for (int index = 0; index < methods()->length(); ++index) {
4663     m = methods()->at(index);
4664     if (m->orig_method_idnum() == idnum) {
4665       return m;
4666     }
4667   }
4668   // None found, return null for the caller to handle.
4669   return nullptr;
4670 }
4671 
4672 
4673 Method* InstanceKlass::method_with_orig_idnum(int idnum, int version) const {
4674   const InstanceKlass* holder = get_klass_version(version);
4675   if (holder == nullptr) {
4676     return nullptr; // The version of klass is gone, no method is found
4677   }
4678   return holder->method_with_orig_idnum(idnum);
4679 }
4680 
4681 #if INCLUDE_JVMTI
4682 JvmtiCachedClassFileData* InstanceKlass::get_cached_class_file() {
4683   return _cached_class_file;
4684 }
4685 
4686 jint InstanceKlass::get_cached_class_file_len() {
4687   return VM_RedefineClasses::get_cached_class_file_len(_cached_class_file);
4688 }
4689 
4690 unsigned char * InstanceKlass::get_cached_class_file_bytes() {
4691   return VM_RedefineClasses::get_cached_class_file_bytes(_cached_class_file);
4692 }
4693 #endif
4694 
4695 // Make a step iterating over the class hierarchy under the root class.
4696 // Skips subclasses if requested.
4697 void ClassHierarchyIterator::next() {
4698   assert(_current != nullptr, "required");
4699   if (_visit_subclasses && _current->subklass() != nullptr) {
4700     _current = _current->subklass();
4701     return; // visit next subclass
4702   }
4703   _visit_subclasses = true; // reset
4704   while (_current->next_sibling() == nullptr && _current != _root) {
4705     _current = _current->java_super(); // backtrack; no more sibling subclasses left
4706   }
4707   if (_current == _root) {
4708     // Iteration is over (back at root after backtracking). Invalidate the iterator.
4709     _current = nullptr;
4710     return;
4711   }
4712   _current = _current->next_sibling();
4713   return; // visit next sibling subclass
4714 }