1 /*
   2  * Copyright (c) 1997, 2025, 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/aotMetaspace.hpp"
  27 #include "cds/archiveUtils.hpp"
  28 #include "cds/cdsConfig.hpp"
  29 #include "cds/cdsEnumKlass.hpp"
  30 #include "cds/classListWriter.hpp"
  31 #include "cds/heapShared.hpp"
  32 #include "classfile/classFileParser.hpp"
  33 #include "classfile/classFileStream.hpp"
  34 #include "classfile/classLoader.hpp"
  35 #include "classfile/classLoaderData.inline.hpp"
  36 #include "classfile/javaClasses.hpp"
  37 #include "classfile/moduleEntry.hpp"
  38 #include "classfile/systemDictionary.hpp"
  39 #include "classfile/systemDictionaryShared.hpp"
  40 #include "classfile/verifier.hpp"
  41 #include "classfile/vmClasses.hpp"
  42 #include "classfile/vmSymbols.hpp"
  43 #include "code/codeCache.hpp"
  44 #include "code/dependencyContext.hpp"
  45 #include "compiler/compilationPolicy.hpp"
  46 #include "compiler/compileBroker.hpp"
  47 #include "gc/shared/collectedHeap.inline.hpp"
  48 #include "interpreter/bytecodeStream.hpp"
  49 #include "interpreter/oopMapCache.hpp"
  50 #include "interpreter/rewriter.hpp"
  51 #include "jvm.h"
  52 #include "jvmtifiles/jvmti.h"
  53 #include "klass.inline.hpp"
  54 #include "logging/log.hpp"
  55 #include "logging/logMessage.hpp"
  56 #include "logging/logStream.hpp"
  57 #include "memory/allocation.inline.hpp"
  58 #include "memory/iterator.inline.hpp"
  59 #include "memory/metadataFactory.hpp"
  60 #include "memory/metaspaceClosure.hpp"
  61 #include "memory/oopFactory.hpp"
  62 #include "memory/resourceArea.hpp"
  63 #include "memory/universe.hpp"
  64 #include "oops/constantPool.hpp"
  65 #include "oops/fieldStreams.inline.hpp"
  66 #include "oops/instanceClassLoaderKlass.hpp"
  67 #include "oops/instanceKlass.inline.hpp"
  68 #include "oops/instanceMirrorKlass.hpp"
  69 #include "oops/instanceOop.hpp"
  70 #include "oops/instanceStackChunkKlass.hpp"
  71 #include "oops/klass.inline.hpp"
  72 #include "oops/method.hpp"
  73 #include "oops/oop.inline.hpp"
  74 #include "oops/recordComponent.hpp"
  75 #include "oops/symbol.hpp"
  76 #include "prims/jvmtiExport.hpp"
  77 #include "prims/jvmtiRedefineClasses.hpp"
  78 #include "prims/jvmtiThreadState.hpp"
  79 #include "prims/methodComparator.hpp"
  80 #include "runtime/arguments.hpp"
  81 #include "runtime/atomic.hpp"
  82 #include "runtime/deoptimization.hpp"
  83 #include "runtime/fieldDescriptor.inline.hpp"
  84 #include "runtime/handles.inline.hpp"
  85 #include "runtime/javaCalls.hpp"
  86 #include "runtime/javaThread.inline.hpp"
  87 #include "runtime/mutexLocker.hpp"
  88 #include "runtime/orderAccess.hpp"
  89 #include "runtime/os.inline.hpp"
  90 #include "runtime/reflection.hpp"
  91 #include "runtime/synchronizer.hpp"
  92 #include "runtime/threads.hpp"
  93 #include "services/classLoadingService.hpp"
  94 #include "services/finalizerService.hpp"
  95 #include "services/threadService.hpp"
  96 #include "utilities/dtrace.hpp"
  97 #include "utilities/events.hpp"
  98 #include "utilities/macros.hpp"
  99 #include "utilities/nativeStackPrinter.hpp"
 100 #include "utilities/stringUtils.hpp"
 101 #ifdef COMPILER1
 102 #include "c1/c1_Compiler.hpp"
 103 #endif
 104 #if INCLUDE_JFR
 105 #include "jfr/jfrEvents.hpp"
 106 #endif
 107 
 108 #ifdef DTRACE_ENABLED
 109 
 110 
 111 #define HOTSPOT_CLASS_INITIALIZATION_required HOTSPOT_CLASS_INITIALIZATION_REQUIRED
 112 #define HOTSPOT_CLASS_INITIALIZATION_recursive HOTSPOT_CLASS_INITIALIZATION_RECURSIVE
 113 #define HOTSPOT_CLASS_INITIALIZATION_concurrent HOTSPOT_CLASS_INITIALIZATION_CONCURRENT
 114 #define HOTSPOT_CLASS_INITIALIZATION_erroneous HOTSPOT_CLASS_INITIALIZATION_ERRONEOUS
 115 #define HOTSPOT_CLASS_INITIALIZATION_super__failed HOTSPOT_CLASS_INITIALIZATION_SUPER_FAILED
 116 #define HOTSPOT_CLASS_INITIALIZATION_clinit HOTSPOT_CLASS_INITIALIZATION_CLINIT
 117 #define HOTSPOT_CLASS_INITIALIZATION_error HOTSPOT_CLASS_INITIALIZATION_ERROR
 118 #define HOTSPOT_CLASS_INITIALIZATION_end HOTSPOT_CLASS_INITIALIZATION_END
 119 #define DTRACE_CLASSINIT_PROBE(type, thread_type)                \
 120   {                                                              \
 121     char* data = nullptr;                                        \
 122     int len = 0;                                                 \
 123     Symbol* clss_name = name();                                  \
 124     if (clss_name != nullptr) {                                  \
 125       data = (char*)clss_name->bytes();                          \
 126       len = clss_name->utf8_length();                            \
 127     }                                                            \
 128     HOTSPOT_CLASS_INITIALIZATION_##type(                         \
 129       data, len, (void*)class_loader(), thread_type);            \
 130   }
 131 
 132 #define DTRACE_CLASSINIT_PROBE_WAIT(type, thread_type, wait)     \
 133   {                                                              \
 134     char* data = nullptr;                                        \
 135     int len = 0;                                                 \
 136     Symbol* clss_name = name();                                  \
 137     if (clss_name != nullptr) {                                  \
 138       data = (char*)clss_name->bytes();                          \
 139       len = clss_name->utf8_length();                            \
 140     }                                                            \
 141     HOTSPOT_CLASS_INITIALIZATION_##type(                         \
 142       data, len, (void*)class_loader(), thread_type, wait);      \
 143   }
 144 
 145 #else //  ndef DTRACE_ENABLED
 146 
 147 #define DTRACE_CLASSINIT_PROBE(type, thread_type)
 148 #define DTRACE_CLASSINIT_PROBE_WAIT(type, thread_type, wait)
 149 
 150 #endif //  ndef DTRACE_ENABLED
 151 
 152 bool InstanceKlass::_finalization_enabled = true;
 153 
 154 static inline bool is_class_loader(const Symbol* class_name,
 155                                    const ClassFileParser& parser) {
 156   assert(class_name != nullptr, "invariant");
 157 
 158   if (class_name == vmSymbols::java_lang_ClassLoader()) {
 159     return true;
 160   }
 161 
 162   if (vmClasses::ClassLoader_klass_loaded()) {
 163     const Klass* const super_klass = parser.super_klass();
 164     if (super_klass != nullptr) {
 165       if (super_klass->is_subtype_of(vmClasses::ClassLoader_klass())) {
 166         return true;
 167       }
 168     }
 169   }
 170   return false;
 171 }
 172 
 173 static inline bool is_stack_chunk_class(const Symbol* class_name,
 174                                         const ClassLoaderData* loader_data) {
 175   return (class_name == vmSymbols::jdk_internal_vm_StackChunk() &&
 176           loader_data->is_the_null_class_loader_data());
 177 }
 178 
 179 // private: called to verify that k is a static member of this nest.
 180 // We know that k is an instance class in the same package and hence the
 181 // same classloader.
 182 bool InstanceKlass::has_nest_member(JavaThread* current, InstanceKlass* k) const {
 183   assert(!is_hidden(), "unexpected hidden class");
 184   if (_nest_members == nullptr || _nest_members == Universe::the_empty_short_array()) {
 185     if (log_is_enabled(Trace, class, nestmates)) {
 186       ResourceMark rm(current);
 187       log_trace(class, nestmates)("Checked nest membership of %s in non-nest-host class %s",
 188                                   k->external_name(), this->external_name());
 189     }
 190     return false;
 191   }
 192 
 193   if (log_is_enabled(Trace, class, nestmates)) {
 194     ResourceMark rm(current);
 195     log_trace(class, nestmates)("Checking nest membership of %s in %s",
 196                                 k->external_name(), this->external_name());
 197   }
 198 
 199   // Check for the named class in _nest_members.
 200   // We don't resolve, or load, any classes.
 201   for (int i = 0; i < _nest_members->length(); i++) {
 202     int cp_index = _nest_members->at(i);
 203     Symbol* name = _constants->klass_name_at(cp_index);
 204     if (name == k->name()) {
 205       log_trace(class, nestmates)("- named class found at nest_members[%d] => cp[%d]", i, cp_index);
 206       return true;
 207     }
 208   }
 209   log_trace(class, nestmates)("- class is NOT a nest member!");
 210   return false;
 211 }
 212 
 213 // Called to verify that k is a permitted subclass of this class.
 214 // The incoming stringStream is used to format the messages for error logging and for the caller
 215 // to use for exception throwing.
 216 bool InstanceKlass::has_as_permitted_subclass(const InstanceKlass* k, stringStream& ss) const {
 217   Thread* current = Thread::current();
 218   assert(k != nullptr, "sanity check");
 219   assert(_permitted_subclasses != nullptr && _permitted_subclasses != Universe::the_empty_short_array(),
 220          "unexpected empty _permitted_subclasses array");
 221 
 222   if (log_is_enabled(Trace, class, sealed)) {
 223     ResourceMark rm(current);
 224     log_trace(class, sealed)("Checking for permitted subclass %s in %s",
 225                              k->external_name(), this->external_name());
 226   }
 227 
 228   // Check that the class and its super are in the same module.
 229   if (k->module() != this->module()) {
 230     ss.print("Failed same module check: subclass %s is in module '%s' with loader %s, "
 231              "and sealed class %s is in module '%s' with loader %s",
 232              k->external_name(),
 233              k->module()->name_as_C_string(),
 234              k->module()->loader_data()->loader_name_and_id(),
 235              this->external_name(),
 236              this->module()->name_as_C_string(),
 237              this->module()->loader_data()->loader_name_and_id());
 238     log_trace(class, sealed)(" - %s", ss.as_string());
 239     return false;
 240   }
 241 
 242   if (!k->is_public() && !is_same_class_package(k)) {
 243     ss.print("Failed same package check: non-public subclass %s is in package '%s' with classloader %s, "
 244              "and sealed class %s is in package '%s' with classloader %s",
 245              k->external_name(),
 246              k->package() != nullptr ? k->package()->name()->as_C_string() : "unnamed",
 247              k->module()->loader_data()->loader_name_and_id(),
 248              this->external_name(),
 249              this->package() != nullptr ? this->package()->name()->as_C_string() : "unnamed",
 250              this->module()->loader_data()->loader_name_and_id());
 251     log_trace(class, sealed)(" - %s", ss.as_string());
 252     return false;
 253   }
 254 
 255   for (int i = 0; i < _permitted_subclasses->length(); i++) {
 256     int cp_index = _permitted_subclasses->at(i);
 257     Symbol* name = _constants->klass_name_at(cp_index);
 258     if (name == k->name()) {
 259       log_trace(class, sealed)("- Found it at permitted_subclasses[%d] => cp[%d]", i, cp_index);
 260       return true;
 261     }
 262   }
 263 
 264   ss.print("Failed listed permitted subclass check: class %s is not a permitted subclass of %s",
 265            k->external_name(), this->external_name());
 266   log_trace(class, sealed)(" - %s", ss.as_string());
 267   return false;
 268 }
 269 
 270 // Return nest-host class, resolving, validating and saving it if needed.
 271 // In cases where this is called from a thread that cannot do classloading
 272 // (such as a native JIT thread) then we simply return null, which in turn
 273 // causes the access check to return false. Such code will retry the access
 274 // from a more suitable environment later. Otherwise the _nest_host is always
 275 // set once this method returns.
 276 // Any errors from nest-host resolution must be preserved so they can be queried
 277 // from higher-level access checking code, and reported as part of access checking
 278 // exceptions.
 279 // VirtualMachineErrors are propagated with a null return.
 280 // Under any conditions where the _nest_host can be set to non-null the resulting
 281 // value of it and, if applicable, the nest host resolution/validation error,
 282 // are idempotent.
 283 InstanceKlass* InstanceKlass::nest_host(TRAPS) {
 284   InstanceKlass* nest_host_k = _nest_host;
 285   if (nest_host_k != nullptr) {
 286     return nest_host_k;
 287   }
 288 
 289   ResourceMark rm(THREAD);
 290 
 291   // need to resolve and save our nest-host class.
 292   if (_nest_host_index != 0) { // we have a real nest_host
 293     // Before trying to resolve check if we're in a suitable context
 294     bool can_resolve = THREAD->can_call_java();
 295     if (!can_resolve && !_constants->tag_at(_nest_host_index).is_klass()) {
 296       log_trace(class, nestmates)("Rejected resolution of nest-host of %s in unsuitable thread",
 297                                   this->external_name());
 298       return nullptr; // sentinel to say "try again from a different context"
 299     }
 300 
 301     log_trace(class, nestmates)("Resolving nest-host of %s using cp entry for %s",
 302                                 this->external_name(),
 303                                 _constants->klass_name_at(_nest_host_index)->as_C_string());
 304 
 305     Klass* k = _constants->klass_at(_nest_host_index, THREAD);
 306     if (HAS_PENDING_EXCEPTION) {
 307       if (PENDING_EXCEPTION->is_a(vmClasses::VirtualMachineError_klass())) {
 308         return nullptr; // propagate VMEs
 309       }
 310       stringStream ss;
 311       char* target_host_class = _constants->klass_name_at(_nest_host_index)->as_C_string();
 312       ss.print("Nest host resolution of %s with host %s failed: ",
 313                this->external_name(), target_host_class);
 314       java_lang_Throwable::print(PENDING_EXCEPTION, &ss);
 315       const char* msg = ss.as_string(true /* on C-heap */);
 316       constantPoolHandle cph(THREAD, constants());
 317       SystemDictionary::add_nest_host_error(cph, _nest_host_index, msg);
 318       CLEAR_PENDING_EXCEPTION;
 319 
 320       log_trace(class, nestmates)("%s", msg);
 321     } else {
 322       // A valid nest-host is an instance class in the current package that lists this
 323       // class as a nest member. If any of these conditions are not met the class is
 324       // its own nest-host.
 325       const char* error = nullptr;
 326 
 327       // JVMS 5.4.4 indicates package check comes first
 328       if (is_same_class_package(k)) {
 329         // Now check actual membership. We can't be a member if our "host" is
 330         // not an instance class.
 331         if (k->is_instance_klass()) {
 332           nest_host_k = InstanceKlass::cast(k);
 333           bool is_member = nest_host_k->has_nest_member(THREAD, this);
 334           if (is_member) {
 335             _nest_host = nest_host_k; // save resolved nest-host value
 336 
 337             log_trace(class, nestmates)("Resolved nest-host of %s to %s",
 338                                         this->external_name(), k->external_name());
 339             return nest_host_k;
 340           } else {
 341             error = "current type is not listed as a nest member";
 342           }
 343         } else {
 344           error = "host is not an instance class";
 345         }
 346       } else {
 347         error = "types are in different packages";
 348       }
 349 
 350       // something went wrong, so record what and log it
 351       {
 352         stringStream ss;
 353         ss.print("Type %s (loader: %s) is not a nest member of type %s (loader: %s): %s",
 354                  this->external_name(),
 355                  this->class_loader_data()->loader_name_and_id(),
 356                  k->external_name(),
 357                  k->class_loader_data()->loader_name_and_id(),
 358                  error);
 359         const char* msg = ss.as_string(true /* on C-heap */);
 360         constantPoolHandle cph(THREAD, constants());
 361         SystemDictionary::add_nest_host_error(cph, _nest_host_index, msg);
 362         log_trace(class, nestmates)("%s", msg);
 363       }
 364     }
 365   } else {
 366     log_trace(class, nestmates)("Type %s is not part of a nest: setting nest-host to self",
 367                                 this->external_name());
 368   }
 369 
 370   // Either not in an explicit nest, or else an error occurred, so
 371   // the nest-host is set to `this`. Any thread that sees this assignment
 372   // will also see any setting of nest_host_error(), if applicable.
 373   return (_nest_host = this);
 374 }
 375 
 376 // Dynamic nest member support: set this class's nest host to the given class.
 377 // This occurs as part of the class definition, as soon as the instanceKlass
 378 // has been created and doesn't require further resolution. The code:
 379 //    lookup().defineHiddenClass(bytes_for_X, NESTMATE);
 380 // results in:
 381 //    class_of_X.set_nest_host(lookup().lookupClass().getNestHost())
 382 // If it has an explicit _nest_host_index or _nest_members, these will be ignored.
 383 // We also know the "host" is a valid nest-host in the same package so we can
 384 // assert some of those facts.
 385 void InstanceKlass::set_nest_host(InstanceKlass* host) {
 386   assert(is_hidden(), "must be a hidden class");
 387   assert(host != nullptr, "null nest host specified");
 388   assert(_nest_host == nullptr, "current class has resolved nest-host");
 389   assert(nest_host_error() == nullptr, "unexpected nest host resolution error exists: %s",
 390          nest_host_error());
 391   assert((host->_nest_host == nullptr && host->_nest_host_index == 0) ||
 392          (host->_nest_host == host), "proposed host is not a valid nest-host");
 393   // Can't assert this as package is not set yet:
 394   // assert(is_same_class_package(host), "proposed host is in wrong package");
 395 
 396   if (log_is_enabled(Trace, class, nestmates)) {
 397     ResourceMark rm;
 398     const char* msg = "";
 399     // a hidden class does not expect a statically defined nest-host
 400     if (_nest_host_index > 0) {
 401       msg = "(the NestHost attribute in the current class is ignored)";
 402     } else if (_nest_members != nullptr && _nest_members != Universe::the_empty_short_array()) {
 403       msg = "(the NestMembers attribute in the current class is ignored)";
 404     }
 405     log_trace(class, nestmates)("Injected type %s into the nest of %s %s",
 406                                 this->external_name(),
 407                                 host->external_name(),
 408                                 msg);
 409   }
 410   // set dynamic nest host
 411   _nest_host = host;
 412   // Record dependency to keep nest host from being unloaded before this class.
 413   ClassLoaderData* this_key = class_loader_data();
 414   assert(this_key != nullptr, "sanity");
 415   this_key->record_dependency(host);
 416 }
 417 
 418 // check if 'this' and k are nestmates (same nest_host), or k is our nest_host,
 419 // or we are k's nest_host - all of which is covered by comparing the two
 420 // resolved_nest_hosts.
 421 // Any exceptions (i.e. VMEs) are propagated.
 422 bool InstanceKlass::has_nestmate_access_to(InstanceKlass* k, TRAPS) {
 423 
 424   assert(this != k, "this should be handled by higher-level code");
 425 
 426   // Per JVMS 5.4.4 we first resolve and validate the current class, then
 427   // the target class k.
 428 
 429   InstanceKlass* cur_host = nest_host(CHECK_false);
 430   if (cur_host == nullptr) {
 431     return false;
 432   }
 433 
 434   Klass* k_nest_host = k->nest_host(CHECK_false);
 435   if (k_nest_host == nullptr) {
 436     return false;
 437   }
 438 
 439   bool access = (cur_host == k_nest_host);
 440 
 441   ResourceMark rm(THREAD);
 442   log_trace(class, nestmates)("Class %s does %shave nestmate access to %s",
 443                               this->external_name(),
 444                               access ? "" : "NOT ",
 445                               k->external_name());
 446   return access;
 447 }
 448 
 449 const char* InstanceKlass::nest_host_error() {
 450   if (_nest_host_index == 0) {
 451     return nullptr;
 452   } else {
 453     constantPoolHandle cph(Thread::current(), constants());
 454     return SystemDictionary::find_nest_host_error(cph, (int)_nest_host_index);
 455   }
 456 }
 457 
 458 void* InstanceKlass::operator new(size_t size, ClassLoaderData* loader_data, size_t word_size,
 459                                   bool use_class_space, TRAPS) throw() {
 460   return Metaspace::allocate(loader_data, word_size, ClassType, use_class_space, THREAD);
 461 }
 462 
 463 InstanceKlass* InstanceKlass::allocate_instance_klass(const ClassFileParser& parser, TRAPS) {
 464   const int size = InstanceKlass::size(parser.vtable_size(),
 465                                        parser.itable_size(),
 466                                        nonstatic_oop_map_size(parser.total_oop_map_count()),
 467                                        parser.is_interface());
 468 
 469   const Symbol* const class_name = parser.class_name();
 470   assert(class_name != nullptr, "invariant");
 471   ClassLoaderData* loader_data = parser.loader_data();
 472   assert(loader_data != nullptr, "invariant");
 473 
 474   InstanceKlass* ik;
 475   const bool use_class_space = UseClassMetaspaceForAllClasses || parser.klass_needs_narrow_id();
 476 
 477   // Allocation
 478   if (parser.is_instance_ref_klass()) {
 479     // java.lang.ref.Reference
 480     ik = new (loader_data, size, use_class_space, THREAD) InstanceRefKlass(parser);
 481   } else if (class_name == vmSymbols::java_lang_Class()) {
 482     // mirror - java.lang.Class
 483     ik = new (loader_data, size, use_class_space, THREAD) InstanceMirrorKlass(parser);
 484   } else if (is_stack_chunk_class(class_name, loader_data)) {
 485     // stack chunk
 486     ik = new (loader_data, size, use_class_space, THREAD) InstanceStackChunkKlass(parser);
 487   } else if (is_class_loader(class_name, parser)) {
 488     // class loader - java.lang.ClassLoader
 489     ik = new (loader_data, size, use_class_space, THREAD) InstanceClassLoaderKlass(parser);
 490   } else {
 491     // normal
 492     ik = new (loader_data, size, use_class_space, THREAD) InstanceKlass(parser);
 493   }
 494 
 495   if (ik != nullptr && UseCompressedClassPointers && use_class_space) {
 496     assert(CompressedKlassPointers::is_encodable(ik),
 497            "Klass " PTR_FORMAT "needs a narrow Klass ID, but is not encodable", p2i(ik));
 498   }
 499 
 500   // Check for pending exception before adding to the loader data and incrementing
 501   // class count.  Can get OOM here.
 502   if (HAS_PENDING_EXCEPTION) {
 503     return nullptr;
 504   }
 505 
 506   return ik;
 507 }
 508 
 509 
 510 // copy method ordering from resource area to Metaspace
 511 void InstanceKlass::copy_method_ordering(const intArray* m, TRAPS) {
 512   if (m != nullptr) {
 513     // allocate a new array and copy contents (memcpy?)
 514     _method_ordering = MetadataFactory::new_array<int>(class_loader_data(), m->length(), CHECK);
 515     for (int i = 0; i < m->length(); i++) {
 516       _method_ordering->at_put(i, m->at(i));
 517     }
 518   } else {
 519     _method_ordering = Universe::the_empty_int_array();
 520   }
 521 }
 522 
 523 // create a new array of vtable_indices for default methods
 524 Array<int>* InstanceKlass::create_new_default_vtable_indices(int len, TRAPS) {
 525   Array<int>* vtable_indices = MetadataFactory::new_array<int>(class_loader_data(), len, CHECK_NULL);
 526   assert(default_vtable_indices() == nullptr, "only create once");
 527   set_default_vtable_indices(vtable_indices);
 528   return vtable_indices;
 529 }
 530 
 531 
 532 InstanceKlass::InstanceKlass() {
 533   assert(CDSConfig::is_dumping_static_archive() || CDSConfig::is_using_archive(), "only for CDS");
 534 }
 535 
 536 InstanceKlass::InstanceKlass(const ClassFileParser& parser, KlassKind kind, ReferenceType reference_type) :
 537   Klass(kind),
 538   _nest_members(nullptr),
 539   _nest_host(nullptr),
 540   _permitted_subclasses(nullptr),
 541   _record_components(nullptr),
 542   _static_field_size(parser.static_field_size()),
 543   _nonstatic_oop_map_size(nonstatic_oop_map_size(parser.total_oop_map_count())),
 544   _itable_len(parser.itable_size()),
 545   _nest_host_index(0),
 546   _init_state(allocated),
 547   _reference_type(reference_type),
 548   _init_thread(nullptr)
 549 {
 550   set_vtable_length(parser.vtable_size());
 551   set_access_flags(parser.access_flags());
 552   if (parser.is_hidden()) set_is_hidden();
 553   set_layout_helper(Klass::instance_layout_helper(parser.layout_size(),
 554                                                     false));
 555 
 556   assert(nullptr == _methods, "underlying memory not zeroed?");
 557   assert(is_instance_klass(), "is layout incorrect?");
 558   assert(size_helper() == parser.layout_size(), "incorrect size_helper?");
 559 }
 560 
 561 void InstanceKlass::deallocate_methods(ClassLoaderData* loader_data,
 562                                        Array<Method*>* methods) {
 563   if (methods != nullptr && methods != Universe::the_empty_method_array() &&
 564       !methods->in_aot_cache()) {
 565     for (int i = 0; i < methods->length(); i++) {
 566       Method* method = methods->at(i);
 567       if (method == nullptr) continue;  // maybe null if error processing
 568       // Only want to delete methods that are not executing for RedefineClasses.
 569       // The previous version will point to them so they're not totally dangling
 570       assert (!method->on_stack(), "shouldn't be called with methods on stack");
 571       MetadataFactory::free_metadata(loader_data, method);
 572     }
 573     MetadataFactory::free_array<Method*>(loader_data, methods);
 574   }
 575 }
 576 
 577 void InstanceKlass::deallocate_interfaces(ClassLoaderData* loader_data,
 578                                           const InstanceKlass* super_klass,
 579                                           Array<InstanceKlass*>* local_interfaces,
 580                                           Array<InstanceKlass*>* transitive_interfaces) {
 581   // Only deallocate transitive interfaces if not empty, same as super class
 582   // or same as local interfaces.  See code in parseClassFile.
 583   Array<InstanceKlass*>* ti = transitive_interfaces;
 584   if (ti != Universe::the_empty_instance_klass_array() && ti != local_interfaces) {
 585     // check that the interfaces don't come from super class
 586     Array<InstanceKlass*>* sti = (super_klass == nullptr) ? nullptr :
 587                     super_klass->transitive_interfaces();
 588     if (ti != sti && ti != nullptr && !ti->in_aot_cache()) {
 589       MetadataFactory::free_array<InstanceKlass*>(loader_data, ti);
 590     }
 591   }
 592 
 593   // local interfaces can be empty
 594   if (local_interfaces != Universe::the_empty_instance_klass_array() &&
 595       local_interfaces != nullptr && !local_interfaces->in_aot_cache()) {
 596     MetadataFactory::free_array<InstanceKlass*>(loader_data, local_interfaces);
 597   }
 598 }
 599 
 600 void InstanceKlass::deallocate_record_components(ClassLoaderData* loader_data,
 601                                                  Array<RecordComponent*>* record_components) {
 602   if (record_components != nullptr && !record_components->in_aot_cache()) {
 603     for (int i = 0; i < record_components->length(); i++) {
 604       RecordComponent* record_component = record_components->at(i);
 605       MetadataFactory::free_metadata(loader_data, record_component);
 606     }
 607     MetadataFactory::free_array<RecordComponent*>(loader_data, record_components);
 608   }
 609 }
 610 
 611 // This function deallocates the metadata and C heap pointers that the
 612 // InstanceKlass points to.
 613 void InstanceKlass::deallocate_contents(ClassLoaderData* loader_data) {
 614   // Orphan the mirror first, CMS thinks it's still live.
 615   if (java_mirror() != nullptr) {
 616     java_lang_Class::set_klass(java_mirror(), nullptr);
 617   }
 618 
 619   // Also remove mirror from handles
 620   loader_data->remove_handle(_java_mirror);
 621 
 622   // Need to take this class off the class loader data list.
 623   loader_data->remove_class(this);
 624 
 625   // The array_klass for this class is created later, after error handling.
 626   // For class redefinition, we keep the original class so this scratch class
 627   // doesn't have an array class.  Either way, assert that there is nothing
 628   // to deallocate.
 629   assert(array_klasses() == nullptr, "array classes shouldn't be created for this class yet");
 630 
 631   // Release C heap allocated data that this points to, which includes
 632   // reference counting symbol names.
 633   // Can't release the constant pool or MethodData C heap data here because the constant
 634   // pool can be deallocated separately from the InstanceKlass for default methods and
 635   // redefine classes.  MethodData can also be released separately.
 636   release_C_heap_structures(/* release_sub_metadata */ false);
 637 
 638   deallocate_methods(loader_data, methods());
 639   set_methods(nullptr);
 640 
 641   deallocate_record_components(loader_data, record_components());
 642   set_record_components(nullptr);
 643 
 644   if (method_ordering() != nullptr &&
 645       method_ordering() != Universe::the_empty_int_array() &&
 646       !method_ordering()->in_aot_cache()) {
 647     MetadataFactory::free_array<int>(loader_data, method_ordering());
 648   }
 649   set_method_ordering(nullptr);
 650 
 651   // default methods can be empty
 652   if (default_methods() != nullptr &&
 653       default_methods() != Universe::the_empty_method_array() &&
 654       !default_methods()->in_aot_cache()) {
 655     MetadataFactory::free_array<Method*>(loader_data, default_methods());
 656   }
 657   // Do NOT deallocate the default methods, they are owned by superinterfaces.
 658   set_default_methods(nullptr);
 659 
 660   // default methods vtable indices can be empty
 661   if (default_vtable_indices() != nullptr &&
 662       !default_vtable_indices()->in_aot_cache()) {
 663     MetadataFactory::free_array<int>(loader_data, default_vtable_indices());
 664   }
 665   set_default_vtable_indices(nullptr);
 666 
 667 
 668   // This array is in Klass, but remove it with the InstanceKlass since
 669   // this place would be the only caller and it can share memory with transitive
 670   // interfaces.
 671   if (secondary_supers() != nullptr &&
 672       secondary_supers() != Universe::the_empty_klass_array() &&
 673       // see comments in compute_secondary_supers about the following cast
 674       (address)(secondary_supers()) != (address)(transitive_interfaces()) &&
 675       !secondary_supers()->in_aot_cache()) {
 676     MetadataFactory::free_array<Klass*>(loader_data, secondary_supers());
 677   }
 678   set_secondary_supers(nullptr, SECONDARY_SUPERS_BITMAP_EMPTY);
 679 
 680   deallocate_interfaces(loader_data, super(), local_interfaces(), transitive_interfaces());
 681   set_transitive_interfaces(nullptr);
 682   set_local_interfaces(nullptr);
 683 
 684   if (fieldinfo_stream() != nullptr && !fieldinfo_stream()->in_aot_cache()) {
 685     MetadataFactory::free_array<u1>(loader_data, fieldinfo_stream());
 686   }
 687   set_fieldinfo_stream(nullptr);
 688 
 689   if (fieldinfo_search_table() != nullptr && !fieldinfo_search_table()->in_aot_cache()) {
 690     MetadataFactory::free_array<u1>(loader_data, fieldinfo_search_table());
 691   }
 692   set_fieldinfo_search_table(nullptr);
 693 
 694   if (fields_status() != nullptr && !fields_status()->in_aot_cache()) {
 695     MetadataFactory::free_array<FieldStatus>(loader_data, fields_status());
 696   }
 697   set_fields_status(nullptr);
 698 
 699   // If a method from a redefined class is using this constant pool, don't
 700   // delete it, yet.  The new class's previous version will point to this.
 701   if (constants() != nullptr) {
 702     assert (!constants()->on_stack(), "shouldn't be called if anything is onstack");
 703     if (!constants()->in_aot_cache()) {
 704       MetadataFactory::free_metadata(loader_data, constants());
 705     }
 706     // Delete any cached resolution errors for the constant pool
 707     SystemDictionary::delete_resolution_error(constants());
 708 
 709     set_constants(nullptr);
 710   }
 711 
 712   if (inner_classes() != nullptr &&
 713       inner_classes() != Universe::the_empty_short_array() &&
 714       !inner_classes()->in_aot_cache()) {
 715     MetadataFactory::free_array<jushort>(loader_data, inner_classes());
 716   }
 717   set_inner_classes(nullptr);
 718 
 719   if (nest_members() != nullptr &&
 720       nest_members() != Universe::the_empty_short_array() &&
 721       !nest_members()->in_aot_cache()) {
 722     MetadataFactory::free_array<jushort>(loader_data, nest_members());
 723   }
 724   set_nest_members(nullptr);
 725 
 726   if (permitted_subclasses() != nullptr &&
 727       permitted_subclasses() != Universe::the_empty_short_array() &&
 728       !permitted_subclasses()->in_aot_cache()) {
 729     MetadataFactory::free_array<jushort>(loader_data, permitted_subclasses());
 730   }
 731   set_permitted_subclasses(nullptr);
 732 
 733   // We should deallocate the Annotations instance if it's not in shared spaces.
 734   if (annotations() != nullptr && !annotations()->in_aot_cache()) {
 735     MetadataFactory::free_metadata(loader_data, annotations());
 736   }
 737   set_annotations(nullptr);
 738 
 739   SystemDictionaryShared::handle_class_unloading(this);
 740 
 741 #if INCLUDE_CDS_JAVA_HEAP
 742   if (CDSConfig::is_dumping_heap()) {
 743     HeapShared::remove_scratch_objects(this);
 744   }
 745 #endif
 746 }
 747 
 748 bool InstanceKlass::is_record() const {
 749   return _record_components != nullptr &&
 750          is_final() &&
 751          super() == vmClasses::Record_klass();
 752 }
 753 
 754 bool InstanceKlass::is_sealed() const {
 755   return _permitted_subclasses != nullptr &&
 756          _permitted_subclasses != Universe::the_empty_short_array();
 757 }
 758 
 759 // JLS 8.9: An enum class is either implicitly final and derives
 760 // from java.lang.Enum, or else is implicitly sealed to its
 761 // anonymous subclasses. This query detects both kinds.
 762 // It does not validate the finality or
 763 // sealing conditions: it merely checks for a super of Enum.
 764 // This is sufficient for recognizing well-formed enums.
 765 bool InstanceKlass::is_enum_subclass() const {
 766   InstanceKlass* s = super();
 767   return (s == vmClasses::Enum_klass() ||
 768           (s != nullptr && s->super() == vmClasses::Enum_klass()));
 769 }
 770 
 771 bool InstanceKlass::should_be_initialized() const {
 772   return !is_initialized();
 773 }
 774 
 775 klassItable InstanceKlass::itable() const {
 776   return klassItable(const_cast<InstanceKlass*>(this));
 777 }
 778 
 779 // JVMTI spec thinks there are signers and protection domain in the
 780 // instanceKlass.  These accessors pretend these fields are there.
 781 // The hprof specification also thinks these fields are in InstanceKlass.
 782 oop InstanceKlass::protection_domain() const {
 783   // return the protection_domain from the mirror
 784   return java_lang_Class::protection_domain(java_mirror());
 785 }
 786 
 787 objArrayOop InstanceKlass::signers() const {
 788   // return the signers from the mirror
 789   return java_lang_Class::signers(java_mirror());
 790 }
 791 
 792 oop InstanceKlass::init_lock() const {
 793   // return the init lock from the mirror
 794   oop lock = java_lang_Class::init_lock(java_mirror());
 795   // Prevent reordering with any access of initialization state
 796   OrderAccess::loadload();
 797   assert(lock != nullptr || !is_not_initialized(), // initialized or in_error state
 798          "only fully initialized state can have a null lock");
 799   return lock;
 800 }
 801 
 802 // Set the initialization lock to null so the object can be GC'ed.  Any racing
 803 // threads to get this lock will see a null lock and will not lock.
 804 // That's okay because they all check for initialized state after getting
 805 // the lock and return.
 806 void InstanceKlass::fence_and_clear_init_lock() {
 807   // make sure previous stores are all done, notably the init_state.
 808   OrderAccess::storestore();
 809   java_lang_Class::clear_init_lock(java_mirror());
 810   assert(!is_not_initialized(), "class must be initialized now");
 811 }
 812 
 813 
 814 // See "The Virtual Machine Specification" section 2.16.5 for a detailed explanation of the class initialization
 815 // process. The step comments refers to the procedure described in that section.
 816 // Note: implementation moved to static method to expose the this pointer.
 817 void InstanceKlass::initialize(TRAPS) {
 818   if (this->should_be_initialized()) {
 819     initialize_impl(CHECK);
 820     // Note: at this point the class may be initialized
 821     //       OR it may be in the state of being initialized
 822     //       in case of recursive initialization!
 823   } else {
 824     assert(is_initialized(), "sanity check");
 825   }
 826 }
 827 
 828 #ifdef ASSERT
 829 void InstanceKlass::assert_no_clinit_will_run_for_aot_initialized_class() const {
 830   assert(has_aot_initialized_mirror(), "must be");
 831 
 832   InstanceKlass* s = super();
 833   if (s != nullptr) {
 834     DEBUG_ONLY(ResourceMark rm);
 835     assert(s->is_initialized(), "super class %s of aot-inited class %s must have been initialized",
 836            s->external_name(), external_name());
 837     s->assert_no_clinit_will_run_for_aot_initialized_class();
 838   }
 839 
 840   Array<InstanceKlass*>* interfaces = local_interfaces();
 841   int len = interfaces->length();
 842   for (int i = 0; i < len; i++) {
 843     InstanceKlass* intf = interfaces->at(i);
 844     if (!intf->is_initialized()) {
 845       ResourceMark rm;
 846       // Note: an interface needs to be marked as is_initialized() only if
 847       // - it has a <clinit>
 848       // - it has declared a default method.
 849       assert(!intf->interface_needs_clinit_execution_as_super(/*also_check_supers*/false),
 850              "uninitialized super interface %s of aot-inited class %s must not have <clinit>",
 851              intf->external_name(), external_name());
 852     }
 853   }
 854 }
 855 #endif
 856 
 857 #if INCLUDE_CDS
 858 void InstanceKlass::initialize_with_aot_initialized_mirror(TRAPS) {
 859   assert(has_aot_initialized_mirror(), "must be");
 860   assert(CDSConfig::is_loading_heap(), "must be");
 861   assert(CDSConfig::is_using_aot_linked_classes(), "must be");
 862   assert_no_clinit_will_run_for_aot_initialized_class();
 863 
 864   if (is_initialized()) {
 865     return;
 866   }
 867 
 868   if (is_runtime_setup_required()) {
 869     // Need to take the slow path, which will call the runtimeSetup() function instead
 870     // of <clinit>
 871     initialize(CHECK);
 872     return;
 873   }
 874   if (log_is_enabled(Info, aot, init)) {
 875     ResourceMark rm;
 876     log_info(aot, init)("%s (aot-inited)", external_name());
 877   }
 878 
 879   link_class(CHECK);
 880 
 881 #ifdef ASSERT
 882   {
 883     Handle h_init_lock(THREAD, init_lock());
 884     ObjectLocker ol(h_init_lock, THREAD);
 885     assert(!is_initialized(), "sanity");
 886     assert(!is_being_initialized(), "sanity");
 887     assert(!is_in_error_state(), "sanity");
 888   }
 889 #endif
 890 
 891   set_init_thread(THREAD);
 892   set_initialization_state_and_notify(fully_initialized, CHECK);
 893 }
 894 #endif
 895 
 896 bool InstanceKlass::verify_code(TRAPS) {
 897   // 1) Verify the bytecodes
 898   return Verifier::verify(this, should_verify_class(), THREAD);
 899 }
 900 
 901 void InstanceKlass::link_class(TRAPS) {
 902   assert(is_loaded(), "must be loaded");
 903   if (!is_linked()) {
 904     link_class_impl(CHECK);
 905   }
 906 }
 907 
 908 // Called to verify that a class can link during initialization, without
 909 // throwing a VerifyError.
 910 bool InstanceKlass::link_class_or_fail(TRAPS) {
 911   assert(is_loaded(), "must be loaded");
 912   if (!is_linked()) {
 913     link_class_impl(CHECK_false);
 914   }
 915   return is_linked();
 916 }
 917 
 918 bool InstanceKlass::link_class_impl(TRAPS) {
 919   if (CDSConfig::is_dumping_static_archive() && SystemDictionaryShared::has_class_failed_verification(this)) {
 920     // This is for CDS static dump only -- we use the in_error_state to indicate that
 921     // the class has failed verification. Throwing the NoClassDefFoundError here is just
 922     // a convenient way to stop repeat attempts to verify the same (bad) class.
 923     //
 924     // Note that the NoClassDefFoundError is not part of the JLS, and should not be thrown
 925     // if we are executing Java code. This is not a problem for CDS dumping phase since
 926     // it doesn't execute any Java code.
 927     ResourceMark rm(THREAD);
 928     // Names are all known to be < 64k so we know this formatted message is not excessively large.
 929     Exceptions::fthrow(THREAD_AND_LOCATION,
 930                        vmSymbols::java_lang_NoClassDefFoundError(),
 931                        "Class %s, or one of its supertypes, failed class initialization",
 932                        external_name());
 933     return false;
 934   }
 935   // return if already verified
 936   if (is_linked()) {
 937     return true;
 938   }
 939 
 940   // Timing
 941   // timer handles recursion
 942   JavaThread* jt = THREAD;
 943 
 944   // link super class before linking this class
 945   InstanceKlass* super_klass = super();
 946   if (super_klass != nullptr) {
 947     if (super_klass->is_interface()) {  // check if super class is an interface
 948       ResourceMark rm(THREAD);
 949       // Names are all known to be < 64k so we know this formatted message is not excessively large.
 950       Exceptions::fthrow(
 951         THREAD_AND_LOCATION,
 952         vmSymbols::java_lang_IncompatibleClassChangeError(),
 953         "class %s has interface %s as super class",
 954         external_name(),
 955         super_klass->external_name()
 956       );
 957       return false;
 958     }
 959 
 960     super_klass->link_class_impl(CHECK_false);
 961   }
 962 
 963   // link all interfaces implemented by this class before linking this class
 964   Array<InstanceKlass*>* interfaces = local_interfaces();
 965   int num_interfaces = interfaces->length();
 966   for (int index = 0; index < num_interfaces; index++) {
 967     InstanceKlass* interk = interfaces->at(index);
 968     interk->link_class_impl(CHECK_false);
 969   }
 970 
 971   // in case the class is linked in the process of linking its superclasses
 972   if (is_linked()) {
 973     return true;
 974   }
 975 
 976   // trace only the link time for this klass that includes
 977   // the verification time
 978   PerfClassTraceTime vmtimer(ClassLoader::perf_class_link_time(),
 979                              ClassLoader::perf_class_link_selftime(),
 980                              ClassLoader::perf_classes_linked(),
 981                              jt->get_thread_stat()->perf_recursion_counts_addr(),
 982                              jt->get_thread_stat()->perf_timers_addr(),
 983                              PerfClassTraceTime::CLASS_LINK);
 984 
 985   // verification & rewriting
 986   {
 987     HandleMark hm(THREAD);
 988     Handle h_init_lock(THREAD, init_lock());
 989     ObjectLocker ol(h_init_lock, jt);
 990     // rewritten will have been set if loader constraint error found
 991     // on an earlier link attempt
 992     // don't verify or rewrite if already rewritten
 993     //
 994 
 995     if (!is_linked()) {
 996       if (!is_rewritten()) {
 997         if (in_aot_cache()) {
 998           assert(!verified_at_dump_time(), "must be");
 999         }
1000         {
1001           bool verify_ok = verify_code(THREAD);
1002           if (!verify_ok) {
1003             return false;
1004           }
1005         }
1006 
1007         // Just in case a side-effect of verify linked this class already
1008         // (which can sometimes happen since the verifier loads classes
1009         // using custom class loaders, which are free to initialize things)
1010         if (is_linked()) {
1011           return true;
1012         }
1013 
1014         // also sets rewritten
1015         rewrite_class(CHECK_false);
1016       } else if (in_aot_cache()) {
1017         SystemDictionaryShared::check_verification_constraints(this, CHECK_false);
1018       }
1019 
1020       // relocate jsrs and link methods after they are all rewritten
1021       link_methods(CHECK_false);
1022 
1023       // Initialize the vtable and interface table after
1024       // methods have been rewritten since rewrite may
1025       // fabricate new Method*s.
1026       // also does loader constraint checking
1027       //
1028       // initialize_vtable and initialize_itable need to be rerun
1029       // for a shared class if
1030       // 1) the class is loaded by custom class loader or
1031       // 2) the class is loaded by built-in class loader but failed to add archived loader constraints or
1032       // 3) the class was not verified during dump time
1033       bool need_init_table = true;
1034       if (in_aot_cache() && verified_at_dump_time() &&
1035           SystemDictionaryShared::check_linking_constraints(THREAD, this)) {
1036         need_init_table = false;
1037       }
1038       if (need_init_table) {
1039         vtable().initialize_vtable_and_check_constraints(CHECK_false);
1040         itable().initialize_itable_and_check_constraints(CHECK_false);
1041       }
1042 #ifdef ASSERT
1043       vtable().verify(tty, true);
1044       // In case itable verification is ever added.
1045       // itable().verify(tty, true);
1046 #endif
1047       if (Universe::is_fully_initialized()) {
1048         DeoptimizationScope deopt_scope;
1049         {
1050           // Now mark all code that assumes the class is not linked.
1051           // Set state under the Compile_lock also.
1052           MutexLocker ml(THREAD, Compile_lock);
1053 
1054           set_init_state(linked);
1055           CodeCache::mark_dependents_on(&deopt_scope, this);
1056         }
1057         // Perform the deopt handshake outside Compile_lock.
1058         deopt_scope.deoptimize_marked();
1059       } else {
1060         set_init_state(linked);
1061       }
1062       if (JvmtiExport::should_post_class_prepare()) {
1063         JvmtiExport::post_class_prepare(THREAD, this);
1064       }
1065     }
1066   }
1067   return true;
1068 }
1069 
1070 // Rewrite the byte codes of all of the methods of a class.
1071 // The rewriter must be called exactly once. Rewriting must happen after
1072 // verification but before the first method of the class is executed.
1073 void InstanceKlass::rewrite_class(TRAPS) {
1074   assert(is_loaded(), "must be loaded");
1075   if (is_rewritten()) {
1076     assert(in_aot_cache(), "rewriting an unshared class?");
1077     return;
1078   }
1079   Rewriter::rewrite(this, CHECK);
1080   set_rewritten();
1081 }
1082 
1083 // Now relocate and link method entry points after class is rewritten.
1084 // This is outside is_rewritten flag. In case of an exception, it can be
1085 // executed more than once.
1086 void InstanceKlass::link_methods(TRAPS) {
1087   PerfTraceTime timer(ClassLoader::perf_ik_link_methods_time());
1088 
1089   int len = methods()->length();
1090   for (int i = len-1; i >= 0; i--) {
1091     methodHandle m(THREAD, methods()->at(i));
1092 
1093     // Set up method entry points for compiler and interpreter    .
1094     m->link_method(m, CHECK);
1095   }
1096 }
1097 
1098 // Eagerly initialize superinterfaces that declare default methods (concrete instance: any access)
1099 void InstanceKlass::initialize_super_interfaces(TRAPS) {
1100   assert (has_nonstatic_concrete_methods(), "caller should have checked this");
1101   for (int i = 0; i < local_interfaces()->length(); ++i) {
1102     InstanceKlass* ik = local_interfaces()->at(i);
1103 
1104     // Initialization is depth first search ie. we start with top of the inheritance tree
1105     // has_nonstatic_concrete_methods drives searching superinterfaces since it
1106     // means has_nonstatic_concrete_methods in its superinterface hierarchy
1107     if (ik->has_nonstatic_concrete_methods()) {
1108       ik->initialize_super_interfaces(CHECK);
1109     }
1110 
1111     // Only initialize() interfaces that "declare" concrete methods.
1112     if (ik->should_be_initialized() && ik->declares_nonstatic_concrete_methods()) {
1113       ik->initialize(CHECK);
1114     }
1115   }
1116 }
1117 
1118 using InitializationErrorTable = HashTable<const InstanceKlass*, OopHandle, 107, AnyObj::C_HEAP, mtClass>;
1119 static InitializationErrorTable* _initialization_error_table;
1120 
1121 void InstanceKlass::add_initialization_error(JavaThread* current, Handle exception) {
1122   // Create the same exception with a message indicating the thread name,
1123   // and the StackTraceElements.
1124   Handle init_error = java_lang_Throwable::create_initialization_error(current, exception);
1125   ResourceMark rm(current);
1126   if (init_error.is_null()) {
1127     log_trace(class, init)("Unable to create the desired initialization error for class %s", external_name());
1128 
1129     // We failed to create the new exception, most likely due to either out-of-memory or
1130     // a stackoverflow error. If the original exception was either of those then we save
1131     // the shared, pre-allocated, stackless, instance of that exception.
1132     if (exception->klass() == vmClasses::StackOverflowError_klass()) {
1133       log_debug(class, init)("Using shared StackOverflowError as initialization error for class %s", external_name());
1134       init_error = Handle(current, Universe::class_init_stack_overflow_error());
1135     } else if (exception->klass() == vmClasses::OutOfMemoryError_klass()) {
1136       log_debug(class, init)("Using shared OutOfMemoryError as initialization error for class %s", external_name());
1137       init_error = Handle(current, Universe::class_init_out_of_memory_error());
1138     } else {
1139       return;
1140     }
1141   }
1142 
1143   MutexLocker ml(current, ClassInitError_lock);
1144   OopHandle elem = OopHandle(Universe::vm_global(), init_error());
1145   bool created;
1146   if (_initialization_error_table == nullptr) {
1147     _initialization_error_table = new (mtClass) InitializationErrorTable();
1148   }
1149   _initialization_error_table->put_if_absent(this, elem, &created);
1150   assert(created, "Initialization is single threaded");
1151   log_trace(class, init)("Initialization error added for class %s", external_name());
1152 }
1153 
1154 oop InstanceKlass::get_initialization_error(JavaThread* current) {
1155   MutexLocker ml(current, ClassInitError_lock);
1156   if (_initialization_error_table == nullptr) {
1157     return nullptr;
1158   }
1159   OopHandle* h = _initialization_error_table->get(this);
1160   return (h != nullptr) ? h->resolve() : nullptr;
1161 }
1162 
1163 // Need to remove entries for unloaded classes.
1164 void InstanceKlass::clean_initialization_error_table() {
1165   struct InitErrorTableCleaner {
1166     bool do_entry(const InstanceKlass* ik, OopHandle h) {
1167       if (!ik->is_loader_alive()) {
1168         h.release(Universe::vm_global());
1169         return true;
1170       } else {
1171         return false;
1172       }
1173     }
1174   };
1175 
1176   assert_locked_or_safepoint(ClassInitError_lock);
1177   InitErrorTableCleaner cleaner;
1178   if (_initialization_error_table != nullptr) {
1179     _initialization_error_table->unlink(&cleaner);
1180   }
1181 }
1182 
1183 void InstanceKlass::initialize_impl(TRAPS) {
1184   HandleMark hm(THREAD);
1185 
1186   // Make sure klass is linked (verified) before initialization
1187   // A class could already be verified, since it has been reflected upon.
1188   link_class(CHECK);
1189 
1190   DTRACE_CLASSINIT_PROBE(required, -1);
1191 
1192   bool wait = false;
1193 
1194   JavaThread* jt = THREAD;
1195 
1196   bool debug_logging_enabled = log_is_enabled(Debug, class, init);
1197 
1198   // refer to the JVM book page 47 for description of steps
1199   // Step 1
1200   {
1201     Handle h_init_lock(THREAD, init_lock());
1202     ObjectLocker ol(h_init_lock, jt);
1203 
1204     // Step 2
1205     // If we were to use wait() instead of waitInterruptibly() then
1206     // we might end up throwing IE from link/symbol resolution sites
1207     // that aren't expected to throw.  This would wreak havoc.  See 6320309.
1208     while (is_being_initialized() && !is_reentrant_initialization(jt)) {
1209       if (debug_logging_enabled) {
1210         ResourceMark rm(jt);
1211         log_debug(class, init)("Thread \"%s\" waiting for initialization of %s by thread \"%s\"",
1212                                jt->name(), external_name(), init_thread_name());
1213       }
1214       wait = true;
1215       jt->set_class_to_be_initialized(this);
1216       ol.wait_uninterruptibly(jt);
1217       jt->set_class_to_be_initialized(nullptr);
1218     }
1219 
1220     // Step 3
1221     if (is_being_initialized() && is_reentrant_initialization(jt)) {
1222       if (debug_logging_enabled) {
1223         ResourceMark rm(jt);
1224         log_debug(class, init)("Thread \"%s\" recursively initializing %s",
1225                                jt->name(), external_name());
1226       }
1227       DTRACE_CLASSINIT_PROBE_WAIT(recursive, -1, wait);
1228       return;
1229     }
1230 
1231     // Step 4
1232     if (is_initialized()) {
1233       if (debug_logging_enabled) {
1234         ResourceMark rm(jt);
1235         log_debug(class, init)("Thread \"%s\" found %s already initialized",
1236                                jt->name(), external_name());
1237       }
1238       DTRACE_CLASSINIT_PROBE_WAIT(concurrent, -1, wait);
1239       return;
1240     }
1241 
1242     // Step 5
1243     if (is_in_error_state()) {
1244       if (debug_logging_enabled) {
1245         ResourceMark rm(jt);
1246         log_debug(class, init)("Thread \"%s\" found %s is in error state",
1247                                jt->name(), external_name());
1248       }
1249 
1250       DTRACE_CLASSINIT_PROBE_WAIT(erroneous, -1, wait);
1251       ResourceMark rm(THREAD);
1252       Handle cause(THREAD, get_initialization_error(THREAD));
1253 
1254       stringStream ss;
1255       ss.print("Could not initialize class %s", external_name());
1256       if (cause.is_null()) {
1257         THROW_MSG(vmSymbols::java_lang_NoClassDefFoundError(), ss.as_string());
1258       } else {
1259         THROW_MSG_CAUSE(vmSymbols::java_lang_NoClassDefFoundError(),
1260                         ss.as_string(), cause);
1261       }
1262     } else {
1263 
1264       // Step 6
1265       set_init_state(being_initialized);
1266       set_init_thread(jt);
1267       if (debug_logging_enabled) {
1268         ResourceMark rm(jt);
1269         log_debug(class, init)("Thread \"%s\" is initializing %s",
1270                                jt->name(), external_name());
1271       }
1272     }
1273   }
1274 
1275   // Step 7
1276   // Next, if C is a class rather than an interface, initialize it's super class and super
1277   // interfaces.
1278   if (!is_interface()) {
1279     Klass* super_klass = super();
1280     if (super_klass != nullptr && super_klass->should_be_initialized()) {
1281       super_klass->initialize(THREAD);
1282     }
1283     // If C implements any interface that declares a non-static, concrete method,
1284     // the initialization of C triggers initialization of its super interfaces.
1285     // Only need to recurse if has_nonstatic_concrete_methods which includes declaring and
1286     // having a superinterface that declares, non-static, concrete methods
1287     if (!HAS_PENDING_EXCEPTION && has_nonstatic_concrete_methods()) {
1288       initialize_super_interfaces(THREAD);
1289     }
1290 
1291     // If any exceptions, complete abruptly, throwing the same exception as above.
1292     if (HAS_PENDING_EXCEPTION) {
1293       Handle e(THREAD, PENDING_EXCEPTION);
1294       CLEAR_PENDING_EXCEPTION;
1295       {
1296         EXCEPTION_MARK;
1297         add_initialization_error(THREAD, e);
1298         // Locks object, set state, and notify all waiting threads
1299         set_initialization_state_and_notify(initialization_error, THREAD);
1300         CLEAR_PENDING_EXCEPTION;
1301       }
1302       DTRACE_CLASSINIT_PROBE_WAIT(super__failed, -1, wait);
1303       THROW_OOP(e());
1304     }
1305   }
1306 
1307 
1308   // Step 8
1309   {
1310     DTRACE_CLASSINIT_PROBE_WAIT(clinit, -1, wait);
1311     if (class_initializer() != nullptr) {
1312       // Timer includes any side effects of class initialization (resolution,
1313       // etc), but not recursive entry into call_class_initializer().
1314       PerfClassTraceTime timer(ClassLoader::perf_class_init_time(),
1315                                ClassLoader::perf_class_init_selftime(),
1316                                ClassLoader::perf_classes_inited(),
1317                                jt->get_thread_stat()->perf_recursion_counts_addr(),
1318                                jt->get_thread_stat()->perf_timers_addr(),
1319                                PerfClassTraceTime::CLASS_CLINIT);
1320       call_class_initializer(THREAD);
1321     } else {
1322       // The elapsed time is so small it's not worth counting.
1323       if (UsePerfData) {
1324         ClassLoader::perf_classes_inited()->inc();
1325       }
1326       call_class_initializer(THREAD);
1327     }
1328   }
1329 
1330   // Step 9
1331   if (!HAS_PENDING_EXCEPTION) {
1332     set_initialization_state_and_notify(fully_initialized, CHECK);
1333     DEBUG_ONLY(vtable().verify(tty, true);)
1334     CompilationPolicy::replay_training_at_init(this, THREAD);
1335   }
1336   else {
1337     // Step 10 and 11
1338     Handle e(THREAD, PENDING_EXCEPTION);
1339     CLEAR_PENDING_EXCEPTION;
1340     // JVMTI has already reported the pending exception
1341     // JVMTI internal flag reset is needed in order to report ExceptionInInitializerError
1342     JvmtiExport::clear_detected_exception(jt);
1343     {
1344       EXCEPTION_MARK;
1345       add_initialization_error(THREAD, e);
1346       set_initialization_state_and_notify(initialization_error, THREAD);
1347       CLEAR_PENDING_EXCEPTION;   // ignore any exception thrown, class initialization error is thrown below
1348       // JVMTI has already reported the pending exception
1349       // JVMTI internal flag reset is needed in order to report ExceptionInInitializerError
1350       JvmtiExport::clear_detected_exception(jt);
1351     }
1352     DTRACE_CLASSINIT_PROBE_WAIT(error, -1, wait);
1353     if (e->is_a(vmClasses::Error_klass())) {
1354       THROW_OOP(e());
1355     } else {
1356       JavaCallArguments args(e);
1357       THROW_ARG(vmSymbols::java_lang_ExceptionInInitializerError(),
1358                 vmSymbols::throwable_void_signature(),
1359                 &args);
1360     }
1361   }
1362   DTRACE_CLASSINIT_PROBE_WAIT(end, -1, wait);
1363 }
1364 
1365 
1366 void InstanceKlass::set_initialization_state_and_notify(ClassState state, TRAPS) {
1367   Handle h_init_lock(THREAD, init_lock());
1368   if (h_init_lock() != nullptr) {
1369     ObjectLocker ol(h_init_lock, THREAD);
1370     set_init_thread(nullptr); // reset _init_thread before changing _init_state
1371     set_init_state(state);
1372     fence_and_clear_init_lock();
1373     ol.notify_all(CHECK);
1374   } else {
1375     assert(h_init_lock() != nullptr, "The initialization state should never be set twice");
1376     set_init_thread(nullptr); // reset _init_thread before changing _init_state
1377     set_init_state(state);
1378   }
1379 }
1380 
1381 // Update hierarchy. This is done before the new klass has been added to the SystemDictionary. The Compile_lock
1382 // is grabbed, to ensure that the compiler is not using the class hierarchy.
1383 void InstanceKlass::add_to_hierarchy(JavaThread* current) {
1384   assert(!SafepointSynchronize::is_at_safepoint(), "must NOT be at safepoint");
1385 
1386   DeoptimizationScope deopt_scope;
1387   {
1388     MutexLocker ml(current, Compile_lock);
1389 
1390     set_init_state(InstanceKlass::loaded);
1391     // make sure init_state store is already done.
1392     // The compiler reads the hierarchy outside of the Compile_lock.
1393     // Access ordering is used to add to hierarchy.
1394 
1395     // Link into hierarchy.
1396     append_to_sibling_list();                    // add to superklass/sibling list
1397     process_interfaces();                        // handle all "implements" declarations
1398 
1399     // Now mark all code that depended on old class hierarchy.
1400     // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1401     if (Universe::is_fully_initialized()) {
1402       CodeCache::mark_dependents_on(&deopt_scope, this);
1403     }
1404   }
1405   // Perform the deopt handshake outside Compile_lock.
1406   deopt_scope.deoptimize_marked();
1407 }
1408 
1409 
1410 InstanceKlass* InstanceKlass::implementor() const {
1411   InstanceKlass* volatile* ik = adr_implementor();
1412   if (ik == nullptr) {
1413     return nullptr;
1414   } else {
1415     // This load races with inserts, and therefore needs acquire.
1416     InstanceKlass* ikls = Atomic::load_acquire(ik);
1417     if (ikls != nullptr && !ikls->is_loader_alive()) {
1418       return nullptr;  // don't return unloaded class
1419     } else {
1420       return ikls;
1421     }
1422   }
1423 }
1424 
1425 
1426 void InstanceKlass::set_implementor(InstanceKlass* ik) {
1427   assert_locked_or_safepoint(Compile_lock);
1428   assert(is_interface(), "not interface");
1429   InstanceKlass* volatile* addr = adr_implementor();
1430   assert(addr != nullptr, "null addr");
1431   if (addr != nullptr) {
1432     Atomic::release_store(addr, ik);
1433   }
1434 }
1435 
1436 int  InstanceKlass::nof_implementors() const {
1437   InstanceKlass* ik = implementor();
1438   if (ik == nullptr) {
1439     return 0;
1440   } else if (ik != this) {
1441     return 1;
1442   } else {
1443     return 2;
1444   }
1445 }
1446 
1447 // The embedded _implementor field can only record one implementor.
1448 // When there are more than one implementors, the _implementor field
1449 // is set to the interface Klass* itself. Following are the possible
1450 // values for the _implementor field:
1451 //   null                  - no implementor
1452 //   implementor Klass*    - one implementor
1453 //   self                  - more than one implementor
1454 //
1455 // The _implementor field only exists for interfaces.
1456 void InstanceKlass::add_implementor(InstanceKlass* ik) {
1457   if (Universe::is_fully_initialized()) {
1458     assert_lock_strong(Compile_lock);
1459   }
1460   assert(is_interface(), "not interface");
1461   // Filter out my subinterfaces.
1462   // (Note: Interfaces are never on the subklass list.)
1463   if (ik->is_interface()) return;
1464 
1465   // Filter out subclasses whose supers already implement me.
1466   // (Note: CHA must walk subclasses of direct implementors
1467   // in order to locate indirect implementors.)
1468   InstanceKlass* super_ik = ik->super();
1469   if (super_ik != nullptr && super_ik->implements_interface(this))
1470     // We only need to check one immediate superclass, since the
1471     // implements_interface query looks at transitive_interfaces.
1472     // Any supers of the super have the same (or fewer) transitive_interfaces.
1473     return;
1474 
1475   InstanceKlass* iklass = implementor();
1476   if (iklass == nullptr) {
1477     set_implementor(ik);
1478   } else if (iklass != this && iklass != ik) {
1479     // There is already an implementor. Use itself as an indicator of
1480     // more than one implementors.
1481     set_implementor(this);
1482   }
1483 
1484   // The implementor also implements the transitive_interfaces
1485   for (int index = 0; index < local_interfaces()->length(); index++) {
1486     local_interfaces()->at(index)->add_implementor(ik);
1487   }
1488 }
1489 
1490 void InstanceKlass::init_implementor() {
1491   if (is_interface()) {
1492     set_implementor(nullptr);
1493   }
1494 }
1495 
1496 
1497 void InstanceKlass::process_interfaces() {
1498   // link this class into the implementors list of every interface it implements
1499   for (int i = local_interfaces()->length() - 1; i >= 0; i--) {
1500     assert(local_interfaces()->at(i)->is_klass(), "must be a klass");
1501     InstanceKlass* interf = local_interfaces()->at(i);
1502     assert(interf->is_interface(), "expected interface");
1503     interf->add_implementor(this);
1504   }
1505 }
1506 
1507 bool InstanceKlass::can_be_primary_super_slow() const {
1508   if (is_interface())
1509     return false;
1510   else
1511     return Klass::can_be_primary_super_slow();
1512 }
1513 
1514 GrowableArray<Klass*>* InstanceKlass::compute_secondary_supers(int num_extra_slots,
1515                                                                Array<InstanceKlass*>* transitive_interfaces) {
1516   // The secondaries are the implemented interfaces.
1517   // We need the cast because Array<Klass*> is NOT a supertype of Array<InstanceKlass*>,
1518   // (but it's safe to do here because we won't write into _secondary_supers from this point on).
1519   Array<Klass*>* interfaces = (Array<Klass*>*)(address)transitive_interfaces;
1520   int num_secondaries = num_extra_slots + interfaces->length();
1521   if (num_secondaries == 0) {
1522     // Must share this for correct bootstrapping!
1523     set_secondary_supers(Universe::the_empty_klass_array(), Universe::the_empty_klass_bitmap());
1524     return nullptr;
1525   } else if (num_extra_slots == 0 && interfaces->length() <= 1) {
1526     // We will reuse the transitive interfaces list if we're certain
1527     // it's in hash order.
1528     uintx bitmap = compute_secondary_supers_bitmap(interfaces);
1529     set_secondary_supers(interfaces, bitmap);
1530     return nullptr;
1531   }
1532   // Copy transitive interfaces to a temporary growable array to be constructed
1533   // into the secondary super list with extra slots.
1534   GrowableArray<Klass*>* secondaries = new GrowableArray<Klass*>(interfaces->length());
1535   for (int i = 0; i < interfaces->length(); i++) {
1536     secondaries->push(interfaces->at(i));
1537   }
1538   return secondaries;
1539 }
1540 
1541 bool InstanceKlass::implements_interface(Klass* k) const {
1542   if (this == k) return true;
1543   assert(k->is_interface(), "should be an interface class");
1544   for (int i = 0; i < transitive_interfaces()->length(); i++) {
1545     if (transitive_interfaces()->at(i) == k) {
1546       return true;
1547     }
1548   }
1549   return false;
1550 }
1551 
1552 bool InstanceKlass::is_same_or_direct_interface(Klass *k) const {
1553   // Verify direct super interface
1554   if (this == k) return true;
1555   assert(k->is_interface(), "should be an interface class");
1556   for (int i = 0; i < local_interfaces()->length(); i++) {
1557     if (local_interfaces()->at(i) == k) {
1558       return true;
1559     }
1560   }
1561   return false;
1562 }
1563 
1564 objArrayOop InstanceKlass::allocate_objArray(int n, int length, TRAPS) {
1565   check_array_allocation_length(length, arrayOopDesc::max_array_length(T_OBJECT), CHECK_NULL);
1566   size_t size = objArrayOopDesc::object_size(length);
1567   ArrayKlass* ak = array_klass(n, CHECK_NULL);
1568   objArrayOop o = (objArrayOop)Universe::heap()->array_allocate(ak, size, length,
1569                                                                 /* do_zero */ true, CHECK_NULL);
1570   return o;
1571 }
1572 
1573 instanceOop InstanceKlass::register_finalizer(instanceOop i, TRAPS) {
1574   if (TraceFinalizerRegistration) {
1575     tty->print("Registered ");
1576     i->print_value_on(tty);
1577     tty->print_cr(" (" PTR_FORMAT ") as finalizable", p2i(i));
1578   }
1579   instanceHandle h_i(THREAD, i);
1580   // Pass the handle as argument, JavaCalls::call expects oop as jobjects
1581   JavaValue result(T_VOID);
1582   JavaCallArguments args(h_i);
1583   methodHandle mh(THREAD, Universe::finalizer_register_method());
1584   JavaCalls::call(&result, mh, &args, CHECK_NULL);
1585   MANAGEMENT_ONLY(FinalizerService::on_register(h_i(), THREAD);)
1586   return h_i();
1587 }
1588 
1589 instanceOop InstanceKlass::allocate_instance(TRAPS) {
1590   assert(!is_abstract() && !is_interface(), "Should not create this object");
1591   size_t size = size_helper();  // Query before forming handle.
1592   return (instanceOop)Universe::heap()->obj_allocate(this, size, CHECK_NULL);
1593 }
1594 
1595 instanceOop InstanceKlass::allocate_instance(oop java_class, TRAPS) {
1596   Klass* k = java_lang_Class::as_Klass(java_class);
1597   if (k == nullptr) {
1598     ResourceMark rm(THREAD);
1599     THROW_(vmSymbols::java_lang_InstantiationException(), nullptr);
1600   }
1601   InstanceKlass* ik = cast(k);
1602   ik->check_valid_for_instantiation(false, CHECK_NULL);
1603   ik->initialize(CHECK_NULL);
1604   return ik->allocate_instance(THREAD);
1605 }
1606 
1607 instanceHandle InstanceKlass::allocate_instance_handle(TRAPS) {
1608   return instanceHandle(THREAD, allocate_instance(THREAD));
1609 }
1610 
1611 void InstanceKlass::check_valid_for_instantiation(bool throwError, TRAPS) {
1612   if (is_interface() || is_abstract()) {
1613     ResourceMark rm(THREAD);
1614     THROW_MSG(throwError ? vmSymbols::java_lang_InstantiationError()
1615               : vmSymbols::java_lang_InstantiationException(), external_name());
1616   }
1617   if (this == vmClasses::Class_klass()) {
1618     ResourceMark rm(THREAD);
1619     THROW_MSG(throwError ? vmSymbols::java_lang_IllegalAccessError()
1620               : vmSymbols::java_lang_IllegalAccessException(), external_name());
1621   }
1622 }
1623 
1624 ArrayKlass* InstanceKlass::array_klass(int n, TRAPS) {
1625   // Need load-acquire for lock-free read
1626   if (array_klasses_acquire() == nullptr) {
1627 
1628     // Recursively lock array allocation
1629     RecursiveLocker rl(MultiArray_lock, THREAD);
1630 
1631     // Check if another thread created the array klass while we were waiting for the lock.
1632     if (array_klasses() == nullptr) {
1633       ObjArrayKlass* k = ObjArrayKlass::allocate_objArray_klass(class_loader_data(), 1, this, CHECK_NULL);
1634       // use 'release' to pair with lock-free load
1635       release_set_array_klasses(k);
1636     }
1637   }
1638 
1639   // array_klasses() will always be set at this point
1640   ObjArrayKlass* ak = array_klasses();
1641   assert(ak != nullptr, "should be set");
1642   return ak->array_klass(n, THREAD);
1643 }
1644 
1645 ArrayKlass* InstanceKlass::array_klass_or_null(int n) {
1646   // Need load-acquire for lock-free read
1647   ObjArrayKlass* oak = array_klasses_acquire();
1648   if (oak == nullptr) {
1649     return nullptr;
1650   } else {
1651     return oak->array_klass_or_null(n);
1652   }
1653 }
1654 
1655 ArrayKlass* InstanceKlass::array_klass(TRAPS) {
1656   return array_klass(1, THREAD);
1657 }
1658 
1659 ArrayKlass* InstanceKlass::array_klass_or_null() {
1660   return array_klass_or_null(1);
1661 }
1662 
1663 static int call_class_initializer_counter = 0;   // for debugging
1664 
1665 Method* InstanceKlass::class_initializer() const {
1666   Method* clinit = find_method(
1667       vmSymbols::class_initializer_name(), vmSymbols::void_method_signature());
1668   if (clinit != nullptr && clinit->has_valid_initializer_flags()) {
1669     return clinit;
1670   }
1671   return nullptr;
1672 }
1673 
1674 void InstanceKlass::call_class_initializer(TRAPS) {
1675   if (ReplayCompiles &&
1676       (ReplaySuppressInitializers == 1 ||
1677        (ReplaySuppressInitializers >= 2 && class_loader() != nullptr))) {
1678     // Hide the existence of the initializer for the purpose of replaying the compile
1679     return;
1680   }
1681 
1682 #if INCLUDE_CDS
1683   // This is needed to ensure the consistency of the archived heap objects.
1684   if (has_aot_initialized_mirror() && CDSConfig::is_loading_heap()) {
1685     AOTClassInitializer::call_runtime_setup(THREAD, this);
1686     return;
1687   } else if (has_archived_enum_objs()) {
1688     assert(in_aot_cache(), "must be");
1689     bool initialized = CDSEnumKlass::initialize_enum_klass(this, CHECK);
1690     if (initialized) {
1691       return;
1692     }
1693   }
1694 #endif
1695 
1696   methodHandle h_method(THREAD, class_initializer());
1697   assert(!is_initialized(), "we cannot initialize twice");
1698   LogTarget(Info, class, init) lt;
1699   if (lt.is_enabled()) {
1700     ResourceMark rm(THREAD);
1701     LogStream ls(lt);
1702     ls.print("%d Initializing ", call_class_initializer_counter++);
1703     name()->print_value_on(&ls);
1704     ls.print_cr("%s (" PTR_FORMAT ") by thread \"%s\"",
1705                 h_method() == nullptr ? "(no method)" : "", p2i(this),
1706                 THREAD->name());
1707   }
1708   if (h_method() != nullptr) {
1709     ThreadInClassInitializer ticl(THREAD, this); // Track class being initialized
1710     JavaCallArguments args; // No arguments
1711     JavaValue result(T_VOID);
1712     JavaCalls::call(&result, h_method, &args, CHECK); // Static call (no args)
1713   }
1714 }
1715 
1716 // If a class that implements this interface is initialized, is the JVM required
1717 // to first execute a <clinit> method declared in this interface,
1718 // or (if also_check_supers==true) any of the super types of this interface?
1719 //
1720 // JVMS 5.5. Initialization, step 7: Next, if C is a class rather than
1721 // an interface, then let SC be its superclass and let SI1, ..., SIn
1722 // be all superinterfaces of C (whether direct or indirect) that
1723 // declare at least one non-abstract, non-static method.
1724 //
1725 // So when an interface is initialized, it does not look at its
1726 // supers. But a proper class will ensure that all of its supers have
1727 // run their <clinit> methods, except that it disregards interfaces
1728 // that lack a non-static concrete method (i.e., a default method).
1729 // Therefore, you should probably call this method only when the
1730 // current class is a super of some proper class, not an interface.
1731 bool InstanceKlass::interface_needs_clinit_execution_as_super(bool also_check_supers) const {
1732   assert(is_interface(), "must be");
1733 
1734   if (!has_nonstatic_concrete_methods()) {
1735     // quick check: no nonstatic concrete methods are declared by this or any super interfaces
1736     return false;
1737   }
1738 
1739   // JVMS 5.5. Initialization
1740   // ...If C is an interface that declares a non-abstract,
1741   // non-static method, the initialization of a class that
1742   // implements C directly or indirectly.
1743   if (declares_nonstatic_concrete_methods() && class_initializer() != nullptr) {
1744     return true;
1745   }
1746   if (also_check_supers) {
1747     Array<InstanceKlass*>* all_ifs = transitive_interfaces();
1748     for (int i = 0; i < all_ifs->length(); ++i) {
1749       InstanceKlass* super_intf = all_ifs->at(i);
1750       if (super_intf->declares_nonstatic_concrete_methods() && super_intf->class_initializer() != nullptr) {
1751         return true;
1752       }
1753     }
1754   }
1755   return false;
1756 }
1757 
1758 void InstanceKlass::mask_for(const methodHandle& method, int bci,
1759   InterpreterOopMap* entry_for) {
1760   // Lazily create the _oop_map_cache at first request.
1761   // Load_acquire is needed to safely get instance published with CAS by another thread.
1762   OopMapCache* oop_map_cache = Atomic::load_acquire(&_oop_map_cache);
1763   if (oop_map_cache == nullptr) {
1764     // Try to install new instance atomically.
1765     oop_map_cache = new OopMapCache();
1766     OopMapCache* other = Atomic::cmpxchg(&_oop_map_cache, (OopMapCache*)nullptr, oop_map_cache);
1767     if (other != nullptr) {
1768       // Someone else managed to install before us, ditch local copy and use the existing one.
1769       delete oop_map_cache;
1770       oop_map_cache = other;
1771     }
1772   }
1773   // _oop_map_cache is constant after init; lookup below does its own locking.
1774   oop_map_cache->lookup(method, bci, entry_for);
1775 }
1776 
1777 bool InstanceKlass::contains_field_offset(int offset) {
1778   fieldDescriptor fd;
1779   return find_field_from_offset(offset, false, &fd);
1780 }
1781 
1782 FieldInfo InstanceKlass::field(int index) const {
1783   for (AllFieldStream fs(this); !fs.done(); fs.next()) {
1784     if (fs.index() == index) {
1785       return fs.to_FieldInfo();
1786     }
1787   }
1788   fatal("Field not found");
1789   return FieldInfo();
1790 }
1791 
1792 bool InstanceKlass::find_local_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
1793   JavaFieldStream fs(this);
1794   if (fs.lookup(name, sig)) {
1795     assert(fs.name() == name, "name must match");
1796     assert(fs.signature() == sig, "signature must match");
1797     fd->reinitialize(const_cast<InstanceKlass*>(this), fs.to_FieldInfo());
1798     return true;
1799   }
1800   return false;
1801 }
1802 
1803 
1804 Klass* InstanceKlass::find_interface_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
1805   const int n = local_interfaces()->length();
1806   for (int i = 0; i < n; i++) {
1807     InstanceKlass* intf1 = local_interfaces()->at(i);
1808     assert(intf1->is_interface(), "just checking type");
1809     // search for field in current interface
1810     if (intf1->find_local_field(name, sig, fd)) {
1811       assert(fd->is_static(), "interface field must be static");
1812       return intf1;
1813     }
1814     // search for field in direct superinterfaces
1815     Klass* intf2 = intf1->find_interface_field(name, sig, fd);
1816     if (intf2 != nullptr) return intf2;
1817   }
1818   // otherwise field lookup fails
1819   return nullptr;
1820 }
1821 
1822 
1823 Klass* InstanceKlass::find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
1824   // search order according to newest JVM spec (5.4.3.2, p.167).
1825   // 1) search for field in current klass
1826   if (find_local_field(name, sig, fd)) {
1827     return const_cast<InstanceKlass*>(this);
1828   }
1829   // 2) search for field recursively in direct superinterfaces
1830   { Klass* intf = find_interface_field(name, sig, fd);
1831     if (intf != nullptr) return intf;
1832   }
1833   // 3) apply field lookup recursively if superclass exists
1834   { InstanceKlass* supr = super();
1835     if (supr != nullptr) return supr->find_field(name, sig, fd);
1836   }
1837   // 4) otherwise field lookup fails
1838   return nullptr;
1839 }
1840 
1841 
1842 Klass* InstanceKlass::find_field(Symbol* name, Symbol* sig, bool is_static, fieldDescriptor* fd) const {
1843   // search order according to newest JVM spec (5.4.3.2, p.167).
1844   // 1) search for field in current klass
1845   if (find_local_field(name, sig, fd)) {
1846     if (fd->is_static() == is_static) return const_cast<InstanceKlass*>(this);
1847   }
1848   // 2) search for field recursively in direct superinterfaces
1849   if (is_static) {
1850     Klass* intf = find_interface_field(name, sig, fd);
1851     if (intf != nullptr) return intf;
1852   }
1853   // 3) apply field lookup recursively if superclass exists
1854   { InstanceKlass* supr = super();
1855     if (supr != nullptr) return supr->find_field(name, sig, is_static, fd);
1856   }
1857   // 4) otherwise field lookup fails
1858   return nullptr;
1859 }
1860 
1861 
1862 bool InstanceKlass::find_local_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const {
1863   for (JavaFieldStream fs(this); !fs.done(); fs.next()) {
1864     if (fs.offset() == offset) {
1865       fd->reinitialize(const_cast<InstanceKlass*>(this), fs.to_FieldInfo());
1866       if (fd->is_static() == is_static) return true;
1867     }
1868   }
1869   return false;
1870 }
1871 
1872 
1873 bool InstanceKlass::find_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const {
1874   const InstanceKlass* klass = this;
1875   while (klass != nullptr) {
1876     if (klass->find_local_field_from_offset(offset, is_static, fd)) {
1877       return true;
1878     }
1879     klass = klass->super();
1880   }
1881   return false;
1882 }
1883 
1884 
1885 void InstanceKlass::methods_do(void f(Method* method)) {
1886   // Methods aren't stable until they are loaded.  This can be read outside
1887   // a lock through the ClassLoaderData for profiling
1888   // Redefined scratch classes are on the list and need to be cleaned
1889   if (!is_loaded() && !is_scratch_class()) {
1890     return;
1891   }
1892 
1893   int len = methods()->length();
1894   for (int index = 0; index < len; index++) {
1895     Method* m = methods()->at(index);
1896     assert(m->is_method(), "must be method");
1897     f(m);
1898   }
1899 }
1900 
1901 
1902 void InstanceKlass::do_local_static_fields(FieldClosure* cl) {
1903   for (JavaFieldStream fs(this); !fs.done(); fs.next()) {
1904     if (fs.access_flags().is_static()) {
1905       fieldDescriptor& fd = fs.field_descriptor();
1906       cl->do_field(&fd);
1907     }
1908   }
1909 }
1910 
1911 
1912 void InstanceKlass::do_local_static_fields(void f(fieldDescriptor*, Handle, TRAPS), Handle mirror, TRAPS) {
1913   for (JavaFieldStream fs(this); !fs.done(); fs.next()) {
1914     if (fs.access_flags().is_static()) {
1915       fieldDescriptor& fd = fs.field_descriptor();
1916       f(&fd, mirror, CHECK);
1917     }
1918   }
1919 }
1920 
1921 void InstanceKlass::do_nonstatic_fields(FieldClosure* cl) {
1922   InstanceKlass* super = this->super();
1923   if (super != nullptr) {
1924     super->do_nonstatic_fields(cl);
1925   }
1926   for (JavaFieldStream fs(this); !fs.done(); fs.next()) {
1927     fieldDescriptor& fd = fs.field_descriptor();
1928     if (!fd.is_static()) {
1929       cl->do_field(&fd);
1930     }
1931   }
1932 }
1933 
1934 static int compare_fields_by_offset(FieldInfo* a, FieldInfo* b) {
1935   return a->offset() - b->offset();
1936 }
1937 
1938 void InstanceKlass::print_nonstatic_fields(FieldClosure* cl) {
1939   InstanceKlass* super = this->super();
1940   if (super != nullptr) {
1941     super->print_nonstatic_fields(cl);
1942   }
1943   ResourceMark rm;
1944   // In DebugInfo nonstatic fields are sorted by offset.
1945   GrowableArray<FieldInfo> fields_sorted;
1946   for (AllFieldStream fs(this); !fs.done(); fs.next()) {
1947     if (!fs.access_flags().is_static()) {
1948       fields_sorted.push(fs.to_FieldInfo());
1949     }
1950   }
1951   int length = fields_sorted.length();
1952   if (length > 0) {
1953     fields_sorted.sort(compare_fields_by_offset);
1954     fieldDescriptor fd;
1955     for (int i = 0; i < length; i++) {
1956       fd.reinitialize(this, fields_sorted.at(i));
1957       assert(!fd.is_static() && fd.offset() == checked_cast<int>(fields_sorted.at(i).offset()), "only nonstatic fields");
1958       cl->do_field(&fd);
1959     }
1960   }
1961 }
1962 
1963 #ifdef ASSERT
1964 static int linear_search(const Array<Method*>* methods,
1965                          const Symbol* name,
1966                          const Symbol* signature) {
1967   const int len = methods->length();
1968   for (int index = 0; index < len; index++) {
1969     const Method* const m = methods->at(index);
1970     assert(m->is_method(), "must be method");
1971     if (m->signature() == signature && m->name() == name) {
1972        return index;
1973     }
1974   }
1975   return -1;
1976 }
1977 #endif
1978 
1979 bool InstanceKlass::_disable_method_binary_search = false;
1980 
1981 NOINLINE int linear_search(const Array<Method*>* methods, const Symbol* name) {
1982   int len = methods->length();
1983   int l = 0;
1984   int h = len - 1;
1985   while (l <= h) {
1986     Method* m = methods->at(l);
1987     if (m->name() == name) {
1988       return l;
1989     }
1990     l++;
1991   }
1992   return -1;
1993 }
1994 
1995 inline int InstanceKlass::quick_search(const Array<Method*>* methods, const Symbol* name) {
1996   if (_disable_method_binary_search) {
1997     assert(CDSConfig::is_dumping_dynamic_archive(), "must be");
1998     // At the final stage of dynamic dumping, the methods array may not be sorted
1999     // by ascending addresses of their names, so we can't use binary search anymore.
2000     // However, methods with the same name are still laid out consecutively inside the
2001     // methods array, so let's look for the first one that matches.
2002     return linear_search(methods, name);
2003   }
2004 
2005   int len = methods->length();
2006   int l = 0;
2007   int h = len - 1;
2008 
2009   // methods are sorted by ascending addresses of their names, so do binary search
2010   while (l <= h) {
2011     int mid = (l + h) >> 1;
2012     Method* m = methods->at(mid);
2013     assert(m->is_method(), "must be method");
2014     int res = m->name()->fast_compare(name);
2015     if (res == 0) {
2016       return mid;
2017     } else if (res < 0) {
2018       l = mid + 1;
2019     } else {
2020       h = mid - 1;
2021     }
2022   }
2023   return -1;
2024 }
2025 
2026 // find_method looks up the name/signature in the local methods array
2027 Method* InstanceKlass::find_method(const Symbol* name,
2028                                    const Symbol* signature) const {
2029   return find_method_impl(name, signature,
2030                           OverpassLookupMode::find,
2031                           StaticLookupMode::find,
2032                           PrivateLookupMode::find);
2033 }
2034 
2035 Method* InstanceKlass::find_method_impl(const Symbol* name,
2036                                         const Symbol* signature,
2037                                         OverpassLookupMode overpass_mode,
2038                                         StaticLookupMode static_mode,
2039                                         PrivateLookupMode private_mode) const {
2040   return InstanceKlass::find_method_impl(methods(),
2041                                          name,
2042                                          signature,
2043                                          overpass_mode,
2044                                          static_mode,
2045                                          private_mode);
2046 }
2047 
2048 // find_instance_method looks up the name/signature in the local methods array
2049 // and skips over static methods
2050 Method* InstanceKlass::find_instance_method(const Array<Method*>* methods,
2051                                             const Symbol* name,
2052                                             const Symbol* signature,
2053                                             PrivateLookupMode private_mode) {
2054   Method* const meth = InstanceKlass::find_method_impl(methods,
2055                                                  name,
2056                                                  signature,
2057                                                  OverpassLookupMode::find,
2058                                                  StaticLookupMode::skip,
2059                                                  private_mode);
2060   assert(((meth == nullptr) || !meth->is_static()),
2061     "find_instance_method should have skipped statics");
2062   return meth;
2063 }
2064 
2065 // find_instance_method looks up the name/signature in the local methods array
2066 // and skips over static methods
2067 Method* InstanceKlass::find_instance_method(const Symbol* name,
2068                                             const Symbol* signature,
2069                                             PrivateLookupMode private_mode) const {
2070   return InstanceKlass::find_instance_method(methods(), name, signature, private_mode);
2071 }
2072 
2073 // Find looks up the name/signature in the local methods array
2074 // and filters on the overpass, static and private flags
2075 // This returns the first one found
2076 // note that the local methods array can have up to one overpass, one static
2077 // and one instance (private or not) with the same name/signature
2078 Method* InstanceKlass::find_local_method(const Symbol* name,
2079                                          const Symbol* signature,
2080                                          OverpassLookupMode overpass_mode,
2081                                          StaticLookupMode static_mode,
2082                                          PrivateLookupMode private_mode) const {
2083   return InstanceKlass::find_method_impl(methods(),
2084                                          name,
2085                                          signature,
2086                                          overpass_mode,
2087                                          static_mode,
2088                                          private_mode);
2089 }
2090 
2091 // Find looks up the name/signature in the local methods array
2092 // and filters on the overpass, static and private flags
2093 // This returns the first one found
2094 // note that the local methods array can have up to one overpass, one static
2095 // and one instance (private or not) with the same name/signature
2096 Method* InstanceKlass::find_local_method(const Array<Method*>* methods,
2097                                          const Symbol* name,
2098                                          const Symbol* signature,
2099                                          OverpassLookupMode overpass_mode,
2100                                          StaticLookupMode static_mode,
2101                                          PrivateLookupMode private_mode) {
2102   return InstanceKlass::find_method_impl(methods,
2103                                          name,
2104                                          signature,
2105                                          overpass_mode,
2106                                          static_mode,
2107                                          private_mode);
2108 }
2109 
2110 Method* InstanceKlass::find_method(const Array<Method*>* methods,
2111                                    const Symbol* name,
2112                                    const Symbol* signature) {
2113   return InstanceKlass::find_method_impl(methods,
2114                                          name,
2115                                          signature,
2116                                          OverpassLookupMode::find,
2117                                          StaticLookupMode::find,
2118                                          PrivateLookupMode::find);
2119 }
2120 
2121 Method* InstanceKlass::find_method_impl(const Array<Method*>* methods,
2122                                         const Symbol* name,
2123                                         const Symbol* signature,
2124                                         OverpassLookupMode overpass_mode,
2125                                         StaticLookupMode static_mode,
2126                                         PrivateLookupMode private_mode) {
2127   int hit = find_method_index(methods, name, signature, overpass_mode, static_mode, private_mode);
2128   return hit >= 0 ? methods->at(hit): nullptr;
2129 }
2130 
2131 // true if method matches signature and conforms to skipping_X conditions.
2132 static bool method_matches(const Method* m,
2133                            const Symbol* signature,
2134                            bool skipping_overpass,
2135                            bool skipping_static,
2136                            bool skipping_private) {
2137   return ((m->signature() == signature) &&
2138     (!skipping_overpass || !m->is_overpass()) &&
2139     (!skipping_static || !m->is_static()) &&
2140     (!skipping_private || !m->is_private()));
2141 }
2142 
2143 // Used directly for default_methods to find the index into the
2144 // default_vtable_indices, and indirectly by find_method
2145 // find_method_index looks in the local methods array to return the index
2146 // of the matching name/signature. If, overpass methods are being ignored,
2147 // the search continues to find a potential non-overpass match.  This capability
2148 // is important during method resolution to prefer a static method, for example,
2149 // over an overpass method.
2150 // There is the possibility in any _method's array to have the same name/signature
2151 // for a static method, an overpass method and a local instance method
2152 // To correctly catch a given method, the search criteria may need
2153 // to explicitly skip the other two. For local instance methods, it
2154 // is often necessary to skip private methods
2155 int InstanceKlass::find_method_index(const Array<Method*>* methods,
2156                                      const Symbol* name,
2157                                      const Symbol* signature,
2158                                      OverpassLookupMode overpass_mode,
2159                                      StaticLookupMode static_mode,
2160                                      PrivateLookupMode private_mode) {
2161   const bool skipping_overpass = (overpass_mode == OverpassLookupMode::skip);
2162   const bool skipping_static = (static_mode == StaticLookupMode::skip);
2163   const bool skipping_private = (private_mode == PrivateLookupMode::skip);
2164   const int hit = quick_search(methods, name);
2165   if (hit != -1) {
2166     const Method* const m = methods->at(hit);
2167 
2168     // Do linear search to find matching signature.  First, quick check
2169     // for common case, ignoring overpasses if requested.
2170     if (method_matches(m, signature, skipping_overpass, skipping_static, skipping_private)) {
2171       return hit;
2172     }
2173 
2174     // search downwards through overloaded methods
2175     int i;
2176     for (i = hit - 1; i >= 0; --i) {
2177         const Method* const m = methods->at(i);
2178         assert(m->is_method(), "must be method");
2179         if (m->name() != name) {
2180           break;
2181         }
2182         if (method_matches(m, signature, skipping_overpass, skipping_static, skipping_private)) {
2183           return i;
2184         }
2185     }
2186     // search upwards
2187     for (i = hit + 1; i < methods->length(); ++i) {
2188         const Method* const m = methods->at(i);
2189         assert(m->is_method(), "must be method");
2190         if (m->name() != name) {
2191           break;
2192         }
2193         if (method_matches(m, signature, skipping_overpass, skipping_static, skipping_private)) {
2194           return i;
2195         }
2196     }
2197     // not found
2198 #ifdef ASSERT
2199     const int index = (skipping_overpass || skipping_static || skipping_private) ? -1 :
2200       linear_search(methods, name, signature);
2201     assert(-1 == index, "binary search should have found entry %d", index);
2202 #endif
2203   }
2204   return -1;
2205 }
2206 
2207 int InstanceKlass::find_method_by_name(const Symbol* name, int* end) const {
2208   return find_method_by_name(methods(), name, end);
2209 }
2210 
2211 int InstanceKlass::find_method_by_name(const Array<Method*>* methods,
2212                                        const Symbol* name,
2213                                        int* end_ptr) {
2214   assert(end_ptr != nullptr, "just checking");
2215   int start = quick_search(methods, name);
2216   int end = start + 1;
2217   if (start != -1) {
2218     while (start - 1 >= 0 && (methods->at(start - 1))->name() == name) --start;
2219     while (end < methods->length() && (methods->at(end))->name() == name) ++end;
2220     *end_ptr = end;
2221     return start;
2222   }
2223   return -1;
2224 }
2225 
2226 // uncached_lookup_method searches both the local class methods array and all
2227 // superclasses methods arrays, skipping any overpass methods in superclasses,
2228 // and possibly skipping private methods.
2229 Method* InstanceKlass::uncached_lookup_method(const Symbol* name,
2230                                               const Symbol* signature,
2231                                               OverpassLookupMode overpass_mode,
2232                                               PrivateLookupMode private_mode) const {
2233   OverpassLookupMode overpass_local_mode = overpass_mode;
2234   const InstanceKlass* klass = this;
2235   while (klass != nullptr) {
2236     Method* const method = klass->find_method_impl(name,
2237                                                    signature,
2238                                                    overpass_local_mode,
2239                                                    StaticLookupMode::find,
2240                                                    private_mode);
2241     if (method != nullptr) {
2242       return method;
2243     }
2244     klass = klass->super();
2245     overpass_local_mode = OverpassLookupMode::skip;   // Always ignore overpass methods in superclasses
2246   }
2247   return nullptr;
2248 }
2249 
2250 #ifdef ASSERT
2251 // search through class hierarchy and return true if this class or
2252 // one of the superclasses was redefined
2253 bool InstanceKlass::has_redefined_this_or_super() const {
2254   const InstanceKlass* klass = this;
2255   while (klass != nullptr) {
2256     if (klass->has_been_redefined()) {
2257       return true;
2258     }
2259     klass = klass->super();
2260   }
2261   return false;
2262 }
2263 #endif
2264 
2265 // lookup a method in the default methods list then in all transitive interfaces
2266 // Do NOT return private or static methods
2267 Method* InstanceKlass::lookup_method_in_ordered_interfaces(Symbol* name,
2268                                                          Symbol* signature) const {
2269   Method* m = nullptr;
2270   if (default_methods() != nullptr) {
2271     m = find_method(default_methods(), name, signature);
2272   }
2273   // Look up interfaces
2274   if (m == nullptr) {
2275     m = lookup_method_in_all_interfaces(name, signature, DefaultsLookupMode::find);
2276   }
2277   return m;
2278 }
2279 
2280 // lookup a method in all the interfaces that this class implements
2281 // Do NOT return private or static methods, new in JDK8 which are not externally visible
2282 // They should only be found in the initial InterfaceMethodRef
2283 Method* InstanceKlass::lookup_method_in_all_interfaces(Symbol* name,
2284                                                        Symbol* signature,
2285                                                        DefaultsLookupMode defaults_mode) const {
2286   Array<InstanceKlass*>* all_ifs = transitive_interfaces();
2287   int num_ifs = all_ifs->length();
2288   InstanceKlass *ik = nullptr;
2289   for (int i = 0; i < num_ifs; i++) {
2290     ik = all_ifs->at(i);
2291     Method* m = ik->lookup_method(name, signature);
2292     if (m != nullptr && m->is_public() && !m->is_static() &&
2293         ((defaults_mode != DefaultsLookupMode::skip) || !m->is_default_method())) {
2294       return m;
2295     }
2296   }
2297   return nullptr;
2298 }
2299 
2300 PrintClassClosure::PrintClassClosure(outputStream* st, bool verbose)
2301   :_st(st), _verbose(verbose) {
2302   ResourceMark rm;
2303   _st->print("%-18s  ", "KlassAddr");
2304   _st->print("%-4s  ", "Size");
2305   _st->print("%-20s  ", "State");
2306   _st->print("%-7s  ", "Flags");
2307   _st->print("%-5s  ", "ClassName");
2308   _st->cr();
2309 }
2310 
2311 void PrintClassClosure::do_klass(Klass* k)  {
2312   ResourceMark rm;
2313   // klass pointer
2314   _st->print(PTR_FORMAT "  ", p2i(k));
2315   // klass size
2316   _st->print("%4d  ", k->size());
2317   // initialization state
2318   if (k->is_instance_klass()) {
2319     _st->print("%-20s  ",InstanceKlass::cast(k)->init_state_name());
2320   } else {
2321     _st->print("%-20s  ","");
2322   }
2323   // misc flags(Changes should synced with ClassesDCmd::ClassesDCmd help doc)
2324   char buf[10];
2325   int i = 0;
2326   if (k->has_finalizer()) buf[i++] = 'F';
2327   if (k->is_instance_klass()) {
2328     InstanceKlass* ik = InstanceKlass::cast(k);
2329     if (ik->has_final_method()) buf[i++] = 'f';
2330     if (ik->is_rewritten()) buf[i++] = 'W';
2331     if (ik->is_contended()) buf[i++] = 'C';
2332     if (ik->has_been_redefined()) buf[i++] = 'R';
2333     if (ik->in_aot_cache()) buf[i++] = 'S';
2334   }
2335   buf[i++] = '\0';
2336   _st->print("%-7s  ", buf);
2337   // klass name
2338   _st->print("%-5s  ", k->external_name());
2339   // end
2340   _st->cr();
2341   if (_verbose) {
2342     k->print_on(_st);
2343   }
2344 }
2345 
2346 /* jni_id_for for jfieldIds only */
2347 JNIid* InstanceKlass::jni_id_for(int offset) {
2348   MutexLocker ml(JfieldIdCreation_lock);
2349   JNIid* probe = jni_ids() == nullptr ? nullptr : jni_ids()->find(offset);
2350   if (probe == nullptr) {
2351     // Allocate new static field identifier
2352     probe = new JNIid(this, offset, jni_ids());
2353     set_jni_ids(probe);
2354   }
2355   return probe;
2356 }
2357 
2358 u2 InstanceKlass::enclosing_method_data(int offset) const {
2359   const Array<jushort>* const inner_class_list = inner_classes();
2360   if (inner_class_list == nullptr) {
2361     return 0;
2362   }
2363   const int length = inner_class_list->length();
2364   if (length % inner_class_next_offset == 0) {
2365     return 0;
2366   }
2367   const int index = length - enclosing_method_attribute_size;
2368   assert(offset < enclosing_method_attribute_size, "invalid offset");
2369   return inner_class_list->at(index + offset);
2370 }
2371 
2372 void InstanceKlass::set_enclosing_method_indices(u2 class_index,
2373                                                  u2 method_index) {
2374   Array<jushort>* inner_class_list = inner_classes();
2375   assert (inner_class_list != nullptr, "_inner_classes list is not set up");
2376   int length = inner_class_list->length();
2377   if (length % inner_class_next_offset == enclosing_method_attribute_size) {
2378     int index = length - enclosing_method_attribute_size;
2379     inner_class_list->at_put(
2380       index + enclosing_method_class_index_offset, class_index);
2381     inner_class_list->at_put(
2382       index + enclosing_method_method_index_offset, method_index);
2383   }
2384 }
2385 
2386 jmethodID InstanceKlass::update_jmethod_id(jmethodID* jmeths, Method* method, int idnum) {
2387   if (method->is_old() && !method->is_obsolete()) {
2388     // If the method passed in is old (but not obsolete), use the current version.
2389     method = method_with_idnum((int)idnum);
2390     assert(method != nullptr, "old and but not obsolete, so should exist");
2391   }
2392   jmethodID new_id = Method::make_jmethod_id(class_loader_data(), method);
2393   Atomic::release_store(&jmeths[idnum + 1], new_id);
2394   return new_id;
2395 }
2396 
2397 // Allocate the jmethodID cache.
2398 static jmethodID* create_jmethod_id_cache(size_t size) {
2399   jmethodID* jmeths = NEW_C_HEAP_ARRAY(jmethodID, size + 1, mtClass);
2400   memset(jmeths, 0, (size + 1) * sizeof(jmethodID));
2401   // cache size is stored in element[0], other elements offset by one
2402   jmeths[0] = (jmethodID)size;
2403   return jmeths;
2404 }
2405 
2406 // When reading outside a lock, use this.
2407 jmethodID* InstanceKlass::methods_jmethod_ids_acquire() const {
2408   return Atomic::load_acquire(&_methods_jmethod_ids);
2409 }
2410 
2411 void InstanceKlass::release_set_methods_jmethod_ids(jmethodID* jmeths) {
2412   Atomic::release_store(&_methods_jmethod_ids, jmeths);
2413 }
2414 
2415 // Lookup or create a jmethodID.
2416 jmethodID InstanceKlass::get_jmethod_id(Method* method) {
2417   int idnum = method->method_idnum();
2418   jmethodID* jmeths = methods_jmethod_ids_acquire();
2419 
2420   // We use a double-check locking idiom here because this cache is
2421   // performance sensitive. In the normal system, this cache only
2422   // transitions from null to non-null which is safe because we use
2423   // release_set_methods_jmethod_ids() to advertise the new cache.
2424   // A partially constructed cache should never be seen by a racing
2425   // thread. We also use release_store() to save a new jmethodID
2426   // in the cache so a partially constructed jmethodID should never be
2427   // seen either. Cache reads of existing jmethodIDs proceed without a
2428   // lock, but cache writes of a new jmethodID requires uniqueness and
2429   // creation of the cache itself requires no leaks so a lock is
2430   // acquired in those two cases.
2431   //
2432   // If the RedefineClasses() API has been used, then this cache grows
2433   // in the redefinition safepoint.
2434 
2435   if (jmeths == nullptr) {
2436     MutexLocker ml(JmethodIdCreation_lock, Mutex::_no_safepoint_check_flag);
2437     jmeths = _methods_jmethod_ids;
2438     // Still null?
2439     if (jmeths == nullptr) {
2440       size_t size = idnum_allocated_count();
2441       assert(size > (size_t)idnum, "should already have space");
2442       jmeths = create_jmethod_id_cache(size);
2443       jmethodID new_id = update_jmethod_id(jmeths, method, idnum);
2444 
2445       // publish jmeths
2446       release_set_methods_jmethod_ids(jmeths);
2447       return new_id;
2448     }
2449   }
2450 
2451   jmethodID id = Atomic::load_acquire(&jmeths[idnum + 1]);
2452   if (id == nullptr) {
2453     MutexLocker ml(JmethodIdCreation_lock, Mutex::_no_safepoint_check_flag);
2454     id = jmeths[idnum + 1];
2455     // Still null?
2456     if (id == nullptr) {
2457       return update_jmethod_id(jmeths, method, idnum);
2458     }
2459   }
2460   return id;
2461 }
2462 
2463 void InstanceKlass::update_methods_jmethod_cache() {
2464   assert(SafepointSynchronize::is_at_safepoint(), "only called at safepoint");
2465   jmethodID* cache = _methods_jmethod_ids;
2466   if (cache != nullptr) {
2467     size_t size = idnum_allocated_count();
2468     size_t old_size = (size_t)cache[0];
2469     if (old_size < size + 1) {
2470       // Allocate a larger one and copy entries to the new one.
2471       // They've already been updated to point to new methods where applicable (i.e., not obsolete).
2472       jmethodID* new_cache = create_jmethod_id_cache(size);
2473 
2474       for (int i = 1; i <= (int)old_size; i++) {
2475         new_cache[i] = cache[i];
2476       }
2477       _methods_jmethod_ids = new_cache;
2478       FREE_C_HEAP_ARRAY(jmethodID, cache);
2479     }
2480   }
2481 }
2482 
2483 // Make a jmethodID for all methods in this class.  This makes getting all method
2484 // ids much, much faster with classes with more than 8
2485 // methods, and has a *substantial* effect on performance with jvmti
2486 // code that loads all jmethodIDs for all classes.
2487 void InstanceKlass::make_methods_jmethod_ids() {
2488   MutexLocker ml(JmethodIdCreation_lock, Mutex::_no_safepoint_check_flag);
2489   jmethodID* jmeths = _methods_jmethod_ids;
2490   if (jmeths == nullptr) {
2491     jmeths = create_jmethod_id_cache(idnum_allocated_count());
2492     release_set_methods_jmethod_ids(jmeths);
2493   }
2494 
2495   int length = methods()->length();
2496   for (int index = 0; index < length; index++) {
2497     Method* m = methods()->at(index);
2498     int idnum = m->method_idnum();
2499     assert(!m->is_old(), "should not have old methods or I'm confused");
2500     jmethodID id = Atomic::load_acquire(&jmeths[idnum + 1]);
2501     if (!m->is_overpass() &&  // skip overpasses
2502         id == nullptr) {
2503       id = Method::make_jmethod_id(class_loader_data(), m);
2504       Atomic::release_store(&jmeths[idnum + 1], id);
2505     }
2506   }
2507 }
2508 
2509 // Lookup a jmethodID, null if not found.  Do no blocking, no allocations, no handles
2510 jmethodID InstanceKlass::jmethod_id_or_null(Method* method) {
2511   int idnum = method->method_idnum();
2512   jmethodID* jmeths = methods_jmethod_ids_acquire();
2513   return (jmeths != nullptr) ? jmeths[idnum + 1] : nullptr;
2514 }
2515 
2516 inline DependencyContext InstanceKlass::dependencies() {
2517   DependencyContext dep_context(&_dep_context, &_dep_context_last_cleaned);
2518   return dep_context;
2519 }
2520 
2521 void InstanceKlass::mark_dependent_nmethods(DeoptimizationScope* deopt_scope, KlassDepChange& changes) {
2522   dependencies().mark_dependent_nmethods(deopt_scope, changes);
2523 }
2524 
2525 void InstanceKlass::add_dependent_nmethod(nmethod* nm) {
2526   assert_lock_strong(CodeCache_lock);
2527   dependencies().add_dependent_nmethod(nm);
2528 }
2529 
2530 void InstanceKlass::clean_dependency_context() {
2531   dependencies().clean_unloading_dependents();
2532 }
2533 
2534 #ifndef PRODUCT
2535 void InstanceKlass::print_dependent_nmethods(bool verbose) {
2536   dependencies().print_dependent_nmethods(verbose);
2537 }
2538 
2539 bool InstanceKlass::is_dependent_nmethod(nmethod* nm) {
2540   return dependencies().is_dependent_nmethod(nm);
2541 }
2542 #endif //PRODUCT
2543 
2544 void InstanceKlass::clean_weak_instanceklass_links() {
2545   clean_implementors_list();
2546   clean_method_data();
2547 }
2548 
2549 void InstanceKlass::clean_implementors_list() {
2550   assert(is_loader_alive(), "this klass should be live");
2551   if (is_interface()) {
2552     assert (ClassUnloading, "only called for ClassUnloading");
2553     for (;;) {
2554       // Use load_acquire due to competing with inserts
2555       InstanceKlass* volatile* iklass = adr_implementor();
2556       assert(iklass != nullptr, "Klass must not be null");
2557       InstanceKlass* impl = Atomic::load_acquire(iklass);
2558       if (impl != nullptr && !impl->is_loader_alive()) {
2559         // null this field, might be an unloaded instance klass or null
2560         if (Atomic::cmpxchg(iklass, impl, (InstanceKlass*)nullptr) == impl) {
2561           // Successfully unlinking implementor.
2562           if (log_is_enabled(Trace, class, unload)) {
2563             ResourceMark rm;
2564             log_trace(class, unload)("unlinking class (implementor): %s", impl->external_name());
2565           }
2566           return;
2567         }
2568       } else {
2569         return;
2570       }
2571     }
2572   }
2573 }
2574 
2575 void InstanceKlass::clean_method_data() {
2576   for (int m = 0; m < methods()->length(); m++) {
2577     MethodData* mdo = methods()->at(m)->method_data();
2578     if (mdo != nullptr) {
2579       mdo->clean_method_data(/*always_clean*/false);
2580     }
2581   }
2582 }
2583 
2584 void InstanceKlass::metaspace_pointers_do(MetaspaceClosure* it) {
2585   Klass::metaspace_pointers_do(it);
2586 
2587   if (log_is_enabled(Trace, aot)) {
2588     ResourceMark rm;
2589     log_trace(aot)("Iter(InstanceKlass): %p (%s)", this, external_name());
2590   }
2591 
2592   it->push(&_annotations);
2593   it->push((Klass**)&_array_klasses);
2594   if (!is_rewritten()) {
2595     it->push(&_constants, MetaspaceClosure::_writable);
2596   } else {
2597     it->push(&_constants);
2598   }
2599   it->push(&_inner_classes);
2600 #if INCLUDE_JVMTI
2601   it->push(&_previous_versions);
2602 #endif
2603 #if INCLUDE_CDS
2604   // For "old" classes with methods containing the jsr bytecode, the _methods array will
2605   // be rewritten during runtime (see Rewriter::rewrite_jsrs()) but they cannot be safely
2606   // checked here with ByteCodeStream. All methods that can't be verified are made writable.
2607   // The length check on the _methods is necessary because classes which don't have any
2608   // methods share the Universe::_the_empty_method_array which is in the RO region.
2609   if (_methods != nullptr && _methods->length() > 0 && !can_be_verified_at_dumptime()) {
2610     // To handle jsr bytecode, new Method* maybe stored into _methods
2611     it->push(&_methods, MetaspaceClosure::_writable);
2612   } else {
2613 #endif
2614     it->push(&_methods);
2615 #if INCLUDE_CDS
2616   }
2617 #endif
2618   it->push(&_default_methods);
2619   it->push(&_local_interfaces);
2620   it->push(&_transitive_interfaces);
2621   it->push(&_method_ordering);
2622   if (!is_rewritten()) {
2623     it->push(&_default_vtable_indices, MetaspaceClosure::_writable);
2624   } else {
2625     it->push(&_default_vtable_indices);
2626   }
2627 
2628   it->push(&_fieldinfo_stream);
2629   it->push(&_fieldinfo_search_table);
2630   // _fields_status might be written into by Rewriter::scan_method() -> fd.set_has_initialized_final_update()
2631   it->push(&_fields_status, MetaspaceClosure::_writable);
2632 
2633   if (itable_length() > 0) {
2634     itableOffsetEntry* ioe = (itableOffsetEntry*)start_of_itable();
2635     int method_table_offset_in_words = ioe->offset()/wordSize;
2636     int itable_offset_in_words = (int)(start_of_itable() - (intptr_t*)this);
2637 
2638     int nof_interfaces = (method_table_offset_in_words - itable_offset_in_words)
2639                          / itableOffsetEntry::size();
2640 
2641     for (int i = 0; i < nof_interfaces; i ++, ioe ++) {
2642       if (ioe->interface_klass() != nullptr) {
2643         it->push(ioe->interface_klass_addr());
2644         itableMethodEntry* ime = ioe->first_method_entry(this);
2645         int n = klassItable::method_count_for_interface(ioe->interface_klass());
2646         for (int index = 0; index < n; index ++) {
2647           it->push(ime[index].method_addr());
2648         }
2649       }
2650     }
2651   }
2652 
2653   it->push(&_nest_host);
2654   it->push(&_nest_members);
2655   it->push(&_permitted_subclasses);
2656   it->push(&_record_components);
2657 }
2658 
2659 #if INCLUDE_CDS
2660 void InstanceKlass::remove_unshareable_info() {
2661 
2662   if (is_linked()) {
2663     assert(can_be_verified_at_dumptime(), "must be");
2664     // Remember this so we can avoid walking the hierarchy at runtime.
2665     set_verified_at_dump_time();
2666   }
2667 
2668   _misc_flags.set_has_init_deps_processed(false);
2669 
2670   Klass::remove_unshareable_info();
2671 
2672   if (SystemDictionaryShared::has_class_failed_verification(this)) {
2673     // Classes are attempted to link during dumping and may fail,
2674     // but these classes are still in the dictionary and class list in CLD.
2675     // If the class has failed verification, there is nothing else to remove.
2676     return;
2677   }
2678 
2679   // Reset to the 'allocated' state to prevent any premature accessing to
2680   // a shared class at runtime while the class is still being loaded and
2681   // restored. A class' init_state is set to 'loaded' at runtime when it's
2682   // being added to class hierarchy (see InstanceKlass:::add_to_hierarchy()).
2683   _init_state = allocated;
2684 
2685   { // Otherwise this needs to take out the Compile_lock.
2686     assert(SafepointSynchronize::is_at_safepoint(), "only called at safepoint");
2687     init_implementor();
2688   }
2689 
2690   // Call remove_unshareable_info() on other objects that belong to this class, except
2691   // for constants()->remove_unshareable_info(), which is called in a separate pass in
2692   // ArchiveBuilder::make_klasses_shareable(),
2693 
2694   for (int i = 0; i < methods()->length(); i++) {
2695     Method* m = methods()->at(i);
2696     m->remove_unshareable_info();
2697   }
2698 
2699   // do array classes also.
2700   if (array_klasses() != nullptr) {
2701     array_klasses()->remove_unshareable_info();
2702   }
2703 
2704   // These are not allocated from metaspace. They are safe to set to null.
2705   _source_debug_extension = nullptr;
2706   _dep_context = nullptr;
2707   _osr_nmethods_head = nullptr;
2708 #if INCLUDE_JVMTI
2709   _breakpoints = nullptr;
2710   _previous_versions = nullptr;
2711   _cached_class_file = nullptr;
2712   _jvmti_cached_class_field_map = nullptr;
2713 #endif
2714 
2715   _init_thread = nullptr;
2716   _methods_jmethod_ids = nullptr;
2717   _jni_ids = nullptr;
2718   _oop_map_cache = nullptr;
2719   if (CDSConfig::is_dumping_method_handles() && HeapShared::is_lambda_proxy_klass(this)) {
2720     // keep _nest_host
2721   } else {
2722     // clear _nest_host to ensure re-load at runtime
2723     _nest_host = nullptr;
2724   }
2725   init_shared_package_entry();
2726   _dep_context_last_cleaned = 0;
2727   DEBUG_ONLY(_shared_class_load_count = 0);
2728 
2729   remove_unshareable_flags();
2730 
2731   DEBUG_ONLY(FieldInfoStream::validate_search_table(_constants, _fieldinfo_stream, _fieldinfo_search_table));
2732 }
2733 
2734 void InstanceKlass::remove_unshareable_flags() {
2735   // clear all the flags/stats that shouldn't be in the archived version
2736   assert(!is_scratch_class(), "must be");
2737   assert(!has_been_redefined(), "must be");
2738 #if INCLUDE_JVMTI
2739   set_is_being_redefined(false);
2740 #endif
2741   set_has_resolved_methods(false);
2742 }
2743 
2744 void InstanceKlass::remove_java_mirror() {
2745   Klass::remove_java_mirror();
2746 
2747   // do array classes also.
2748   if (array_klasses() != nullptr) {
2749     array_klasses()->remove_java_mirror();
2750   }
2751 }
2752 
2753 void InstanceKlass::init_shared_package_entry() {
2754   assert(CDSConfig::is_dumping_archive(), "must be");
2755 #if !INCLUDE_CDS_JAVA_HEAP
2756   _package_entry = nullptr;
2757 #else
2758   if (CDSConfig::is_dumping_full_module_graph()) {
2759     if (defined_by_other_loaders()) {
2760       _package_entry = nullptr;
2761     } else {
2762       _package_entry = PackageEntry::get_archived_entry(_package_entry);
2763     }
2764   } else if (CDSConfig::is_dumping_dynamic_archive() &&
2765              CDSConfig::is_using_full_module_graph() &&
2766              AOTMetaspace::in_aot_cache(_package_entry)) {
2767     // _package_entry is an archived package in the base archive. Leave it as is.
2768   } else {
2769     _package_entry = nullptr;
2770   }
2771   ArchivePtrMarker::mark_pointer((address**)&_package_entry);
2772 #endif
2773 }
2774 
2775 void InstanceKlass::compute_has_loops_flag_for_methods() {
2776   Array<Method*>* methods = this->methods();
2777   for (int index = 0; index < methods->length(); ++index) {
2778     Method* m = methods->at(index);
2779     if (!m->is_overpass()) { // work around JDK-8305771
2780       m->compute_has_loops_flag();
2781     }
2782   }
2783 }
2784 
2785 void InstanceKlass::restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain,
2786                                              PackageEntry* pkg_entry, TRAPS) {
2787   // InstanceKlass::add_to_hierarchy() sets the init_state to loaded
2788   // before the InstanceKlass is added to the SystemDictionary. Make
2789   // sure the current state is <loaded.
2790   assert(!is_loaded(), "invalid init state");
2791   assert(!shared_loading_failed(), "Must not try to load failed class again");
2792   set_package(loader_data, pkg_entry, CHECK);
2793   Klass::restore_unshareable_info(loader_data, protection_domain, CHECK);
2794 
2795   Array<Method*>* methods = this->methods();
2796   int num_methods = methods->length();
2797   for (int index = 0; index < num_methods; ++index) {
2798     methods->at(index)->restore_unshareable_info(CHECK);
2799   }
2800 #if INCLUDE_JVMTI
2801   if (JvmtiExport::has_redefined_a_class()) {
2802     // Reinitialize vtable because RedefineClasses may have changed some
2803     // entries in this vtable for super classes so the CDS vtable might
2804     // point to old or obsolete entries.  RedefineClasses doesn't fix up
2805     // vtables in the shared system dictionary, only the main one.
2806     // It also redefines the itable too so fix that too.
2807     // First fix any default methods that point to a super class that may
2808     // have been redefined.
2809     bool trace_name_printed = false;
2810     adjust_default_methods(&trace_name_printed);
2811     if (verified_at_dump_time()) {
2812       // Initialize vtable and itable for classes which can be verified at dump time.
2813       // Unlinked classes such as old classes with major version < 50 cannot be verified
2814       // at dump time.
2815       vtable().initialize_vtable();
2816       itable().initialize_itable();
2817     }
2818   }
2819 #endif // INCLUDE_JVMTI
2820 
2821   // restore constant pool resolved references
2822   constants()->restore_unshareable_info(CHECK);
2823 
2824   if (array_klasses() != nullptr) {
2825     // To get a consistent list of classes we need MultiArray_lock to ensure
2826     // array classes aren't observed while they are being restored.
2827     RecursiveLocker rl(MultiArray_lock, THREAD);
2828     assert(this == array_klasses()->bottom_klass(), "sanity");
2829     // Array classes have null protection domain.
2830     // --> see ArrayKlass::complete_create_array_klass()
2831     array_klasses()->restore_unshareable_info(class_loader_data(), Handle(), CHECK);
2832   }
2833 
2834   // Initialize @ValueBased class annotation if not already set in the archived klass.
2835   if (DiagnoseSyncOnValueBasedClasses && has_value_based_class_annotation() && !is_value_based()) {
2836     set_is_value_based();
2837   }
2838 
2839   DEBUG_ONLY(FieldInfoStream::validate_search_table(_constants, _fieldinfo_stream, _fieldinfo_search_table));
2840 }
2841 
2842 // Check if a class or any of its supertypes has a version older than 50.
2843 // CDS will not perform verification of old classes during dump time because
2844 // without changing the old verifier, the verification constraint cannot be
2845 // retrieved during dump time.
2846 // Verification of archived old classes will be performed during run time.
2847 bool InstanceKlass::can_be_verified_at_dumptime() const {
2848   if (AOTMetaspace::in_aot_cache(this)) {
2849     // This is a class that was dumped into the base archive, so we know
2850     // it was verified at dump time.
2851     return true;
2852   }
2853   if (major_version() < 50 /*JAVA_6_VERSION*/) {
2854     return false;
2855   }
2856   if (super() != nullptr && !super()->can_be_verified_at_dumptime()) {
2857     return false;
2858   }
2859   Array<InstanceKlass*>* interfaces = local_interfaces();
2860   int len = interfaces->length();
2861   for (int i = 0; i < len; i++) {
2862     if (!interfaces->at(i)->can_be_verified_at_dumptime()) {
2863       return false;
2864     }
2865   }
2866   return true;
2867 }
2868 
2869 #endif // INCLUDE_CDS
2870 
2871 #if INCLUDE_JVMTI
2872 static void clear_all_breakpoints(Method* m) {
2873   m->clear_all_breakpoints();
2874 }
2875 #endif
2876 
2877 void InstanceKlass::unload_class(InstanceKlass* ik) {
2878 
2879   if (ik->is_scratch_class()) {
2880     assert(ik->dependencies().is_empty(), "dependencies should be empty for scratch classes");
2881     return;
2882   }
2883   assert(ik->is_loaded(), "class should be loaded " PTR_FORMAT, p2i(ik));
2884 
2885   // Release dependencies.
2886   ik->dependencies().remove_all_dependents();
2887 
2888   // notify the debugger
2889   if (JvmtiExport::should_post_class_unload()) {
2890     JvmtiExport::post_class_unload(ik);
2891   }
2892 
2893   // notify ClassLoadingService of class unload
2894   ClassLoadingService::notify_class_unloaded(ik);
2895 
2896   SystemDictionaryShared::handle_class_unloading(ik);
2897 
2898   if (log_is_enabled(Info, class, unload)) {
2899     ResourceMark rm;
2900     log_info(class, unload)("unloading class %s " PTR_FORMAT, ik->external_name(), p2i(ik));
2901   }
2902 
2903   Events::log_class_unloading(Thread::current(), ik);
2904 
2905 #if INCLUDE_JFR
2906   assert(ik != nullptr, "invariant");
2907   EventClassUnload event;
2908   event.set_unloadedClass(ik);
2909   event.set_definingClassLoader(ik->class_loader_data());
2910   event.commit();
2911 #endif
2912 }
2913 
2914 static void method_release_C_heap_structures(Method* m) {
2915   m->release_C_heap_structures();
2916 }
2917 
2918 // Called also by InstanceKlass::deallocate_contents, with false for release_sub_metadata.
2919 void InstanceKlass::release_C_heap_structures(bool release_sub_metadata) {
2920   // Clean up C heap
2921   Klass::release_C_heap_structures();
2922 
2923   // Deallocate and call destructors for MDO mutexes
2924   if (release_sub_metadata) {
2925     methods_do(method_release_C_heap_structures);
2926   }
2927 
2928   // Deallocate oop map cache
2929   if (_oop_map_cache != nullptr) {
2930     delete _oop_map_cache;
2931     _oop_map_cache = nullptr;
2932   }
2933 
2934   // Deallocate JNI identifiers for jfieldIDs
2935   JNIid::deallocate(jni_ids());
2936   set_jni_ids(nullptr);
2937 
2938   jmethodID* jmeths = _methods_jmethod_ids;
2939   if (jmeths != nullptr) {
2940     release_set_methods_jmethod_ids(nullptr);
2941     FreeHeap(jmeths);
2942   }
2943 
2944   assert(_dep_context == nullptr,
2945          "dependencies should already be cleaned");
2946 
2947 #if INCLUDE_JVMTI
2948   // Deallocate breakpoint records
2949   if (breakpoints() != nullptr) {
2950     methods_do(clear_all_breakpoints);
2951     assert(breakpoints() == nullptr, "should have cleared breakpoints");
2952   }
2953 
2954   // deallocate the cached class file
2955   if (_cached_class_file != nullptr) {
2956     os::free(_cached_class_file);
2957     _cached_class_file = nullptr;
2958   }
2959 #endif
2960 
2961   FREE_C_HEAP_ARRAY(char, _source_debug_extension);
2962 
2963   if (release_sub_metadata) {
2964     constants()->release_C_heap_structures();
2965   }
2966 }
2967 
2968 // The constant pool is on stack if any of the methods are executing or
2969 // referenced by handles.
2970 bool InstanceKlass::on_stack() const {
2971   return _constants->on_stack();
2972 }
2973 
2974 Symbol* InstanceKlass::source_file_name() const               { return _constants->source_file_name(); }
2975 u2 InstanceKlass::source_file_name_index() const              { return _constants->source_file_name_index(); }
2976 void InstanceKlass::set_source_file_name_index(u2 sourcefile_index) { _constants->set_source_file_name_index(sourcefile_index); }
2977 
2978 // minor and major version numbers of class file
2979 u2 InstanceKlass::minor_version() const                 { return _constants->minor_version(); }
2980 void InstanceKlass::set_minor_version(u2 minor_version) { _constants->set_minor_version(minor_version); }
2981 u2 InstanceKlass::major_version() const                 { return _constants->major_version(); }
2982 void InstanceKlass::set_major_version(u2 major_version) { _constants->set_major_version(major_version); }
2983 
2984 const InstanceKlass* InstanceKlass::get_klass_version(int version) const {
2985   for (const InstanceKlass* ik = this; ik != nullptr; ik = ik->previous_versions()) {
2986     if (ik->constants()->version() == version) {
2987       return ik;
2988     }
2989   }
2990   return nullptr;
2991 }
2992 
2993 void InstanceKlass::set_source_debug_extension(const char* array, int length) {
2994   if (array == nullptr) {
2995     _source_debug_extension = nullptr;
2996   } else {
2997     // Adding one to the attribute length in order to store a null terminator
2998     // character could cause an overflow because the attribute length is
2999     // already coded with an u4 in the classfile, but in practice, it's
3000     // unlikely to happen.
3001     assert((length+1) > length, "Overflow checking");
3002     char* sde = NEW_C_HEAP_ARRAY(char, (length + 1), mtClass);
3003     for (int i = 0; i < length; i++) {
3004       sde[i] = array[i];
3005     }
3006     sde[length] = '\0';
3007     _source_debug_extension = sde;
3008   }
3009 }
3010 
3011 Symbol* InstanceKlass::generic_signature() const                   { return _constants->generic_signature(); }
3012 u2 InstanceKlass::generic_signature_index() const                  { return _constants->generic_signature_index(); }
3013 void InstanceKlass::set_generic_signature_index(u2 sig_index)      { _constants->set_generic_signature_index(sig_index); }
3014 
3015 const char* InstanceKlass::signature_name() const {
3016 
3017   // Get the internal name as a c string
3018   const char* src = (const char*) (name()->as_C_string());
3019   const int src_length = (int)strlen(src);
3020 
3021   char* dest = NEW_RESOURCE_ARRAY(char, src_length + 3);
3022 
3023   // Add L as type indicator
3024   int dest_index = 0;
3025   dest[dest_index++] = JVM_SIGNATURE_CLASS;
3026 
3027   // Add the actual class name
3028   for (int src_index = 0; src_index < src_length; ) {
3029     dest[dest_index++] = src[src_index++];
3030   }
3031 
3032   if (is_hidden()) { // Replace the last '+' with a '.'.
3033     for (int index = (int)src_length; index > 0; index--) {
3034       if (dest[index] == '+') {
3035         dest[index] = JVM_SIGNATURE_DOT;
3036         break;
3037       }
3038     }
3039   }
3040 
3041   // Add the semicolon and the null
3042   dest[dest_index++] = JVM_SIGNATURE_ENDCLASS;
3043   dest[dest_index] = '\0';
3044   return dest;
3045 }
3046 
3047 ModuleEntry* InstanceKlass::module() const {
3048   if (is_hidden() &&
3049       in_unnamed_package() &&
3050       class_loader_data()->has_class_mirror_holder()) {
3051     // For a non-strong hidden class defined to an unnamed package,
3052     // its (class held) CLD will not have an unnamed module created for it.
3053     // Two choices to find the correct ModuleEntry:
3054     // 1. If hidden class is within a nest, use nest host's module
3055     // 2. Find the unnamed module off from the class loader
3056     // For now option #2 is used since a nest host is not set until
3057     // after the instance class is created in jvm_lookup_define_class().
3058     if (class_loader_data()->is_boot_class_loader_data()) {
3059       return ClassLoaderData::the_null_class_loader_data()->unnamed_module();
3060     } else {
3061       oop module = java_lang_ClassLoader::unnamedModule(class_loader_data()->class_loader());
3062       assert(java_lang_Module::is_instance(module), "Not an instance of java.lang.Module");
3063       return java_lang_Module::module_entry(module);
3064     }
3065   }
3066 
3067   // Class is in a named package
3068   if (!in_unnamed_package()) {
3069     return _package_entry->module();
3070   }
3071 
3072   // Class is in an unnamed package, return its loader's unnamed module
3073   return class_loader_data()->unnamed_module();
3074 }
3075 
3076 bool InstanceKlass::in_javabase_module() const {
3077   return module()->name() == vmSymbols::java_base();
3078 }
3079 
3080 void InstanceKlass::set_package(ClassLoaderData* loader_data, PackageEntry* pkg_entry, TRAPS) {
3081 
3082   // ensure java/ packages only loaded by boot or platform builtin loaders
3083   // not needed for shared class since CDS does not archive prohibited classes.
3084   if (!in_aot_cache()) {
3085     check_prohibited_package(name(), loader_data, CHECK);
3086   }
3087 
3088   if (in_aot_cache() && _package_entry != nullptr) {
3089     if (CDSConfig::is_using_full_module_graph() && _package_entry == pkg_entry) {
3090       // we can use the saved package
3091       assert(AOTMetaspace::in_aot_cache(_package_entry), "must be");
3092       return;
3093     } else {
3094       _package_entry = nullptr;
3095     }
3096   }
3097 
3098   // ClassLoader::package_from_class_name has already incremented the refcount of the symbol
3099   // it returns, so we need to decrement it when the current function exits.
3100   TempNewSymbol from_class_name =
3101       (pkg_entry != nullptr) ? nullptr : ClassLoader::package_from_class_name(name());
3102 
3103   Symbol* pkg_name;
3104   if (pkg_entry != nullptr) {
3105     pkg_name = pkg_entry->name();
3106   } else {
3107     pkg_name = from_class_name;
3108   }
3109 
3110   if (pkg_name != nullptr && loader_data != nullptr) {
3111 
3112     // Find in class loader's package entry table.
3113     _package_entry = pkg_entry != nullptr ? pkg_entry : loader_data->packages()->lookup_only(pkg_name);
3114 
3115     // If the package name is not found in the loader's package
3116     // entry table, it is an indication that the package has not
3117     // been defined. Consider it defined within the unnamed module.
3118     if (_package_entry == nullptr) {
3119 
3120       if (!ModuleEntryTable::javabase_defined()) {
3121         // Before java.base is defined during bootstrapping, define all packages in
3122         // the java.base module.  If a non-java.base package is erroneously placed
3123         // in the java.base module it will be caught later when java.base
3124         // is defined by ModuleEntryTable::verify_javabase_packages check.
3125         assert(ModuleEntryTable::javabase_moduleEntry() != nullptr, JAVA_BASE_NAME " module is null");
3126         _package_entry = loader_data->packages()->create_entry_if_absent(pkg_name, ModuleEntryTable::javabase_moduleEntry());
3127       } else {
3128         assert(loader_data->unnamed_module() != nullptr, "unnamed module is null");
3129         _package_entry = loader_data->packages()->create_entry_if_absent(pkg_name, loader_data->unnamed_module());
3130       }
3131 
3132       // A package should have been successfully created
3133       DEBUG_ONLY(ResourceMark rm(THREAD));
3134       assert(_package_entry != nullptr, "Package entry for class %s not found, loader %s",
3135              name()->as_C_string(), loader_data->loader_name_and_id());
3136     }
3137 
3138     if (log_is_enabled(Debug, module)) {
3139       ResourceMark rm(THREAD);
3140       ModuleEntry* m = _package_entry->module();
3141       log_trace(module)("Setting package: class: %s, package: %s, loader: %s, module: %s",
3142                         external_name(),
3143                         pkg_name->as_C_string(),
3144                         loader_data->loader_name_and_id(),
3145                         (m->is_named() ? m->name()->as_C_string() : UNNAMED_MODULE));
3146     }
3147   } else {
3148     ResourceMark rm(THREAD);
3149     log_trace(module)("Setting package: class: %s, package: unnamed, loader: %s, module: %s",
3150                       external_name(),
3151                       (loader_data != nullptr) ? loader_data->loader_name_and_id() : "null",
3152                       UNNAMED_MODULE);
3153   }
3154 }
3155 
3156 // Function set_classpath_index ensures that for a non-null _package_entry
3157 // of the InstanceKlass, the entry is in the boot loader's package entry table.
3158 // It then sets the classpath_index in the package entry record.
3159 //
3160 // The classpath_index field is used to find the entry on the boot loader class
3161 // path for packages with classes loaded by the boot loader from -Xbootclasspath/a
3162 // in an unnamed module.  It is also used to indicate (for all packages whose
3163 // classes are loaded by the boot loader) that at least one of the package's
3164 // classes has been loaded.
3165 void InstanceKlass::set_classpath_index(s2 path_index) {
3166   if (_package_entry != nullptr) {
3167     DEBUG_ONLY(PackageEntryTable* pkg_entry_tbl = ClassLoaderData::the_null_class_loader_data()->packages();)
3168     assert(pkg_entry_tbl->lookup_only(_package_entry->name()) == _package_entry, "Should be same");
3169     assert(path_index != -1, "Unexpected classpath_index");
3170     _package_entry->set_classpath_index(path_index);
3171   }
3172 }
3173 
3174 // different versions of is_same_class_package
3175 
3176 bool InstanceKlass::is_same_class_package(const Klass* class2) const {
3177   oop classloader1 = this->class_loader();
3178   PackageEntry* classpkg1 = this->package();
3179   if (class2->is_objArray_klass()) {
3180     class2 = ObjArrayKlass::cast(class2)->bottom_klass();
3181   }
3182 
3183   oop classloader2;
3184   PackageEntry* classpkg2;
3185   if (class2->is_instance_klass()) {
3186     classloader2 = class2->class_loader();
3187     classpkg2 = class2->package();
3188   } else {
3189     assert(class2->is_typeArray_klass(), "should be type array");
3190     classloader2 = nullptr;
3191     classpkg2 = nullptr;
3192   }
3193 
3194   // Same package is determined by comparing class loader
3195   // and package entries. Both must be the same. This rule
3196   // applies even to classes that are defined in the unnamed
3197   // package, they still must have the same class loader.
3198   if ((classloader1 == classloader2) && (classpkg1 == classpkg2)) {
3199     return true;
3200   }
3201 
3202   return false;
3203 }
3204 
3205 // return true if this class and other_class are in the same package. Classloader
3206 // and classname information is enough to determine a class's package
3207 bool InstanceKlass::is_same_class_package(oop other_class_loader,
3208                                           const Symbol* other_class_name) const {
3209   if (class_loader() != other_class_loader) {
3210     return false;
3211   }
3212   if (name()->fast_compare(other_class_name) == 0) {
3213      return true;
3214   }
3215 
3216   {
3217     ResourceMark rm;
3218 
3219     bool bad_class_name = false;
3220     TempNewSymbol other_pkg = ClassLoader::package_from_class_name(other_class_name, &bad_class_name);
3221     if (bad_class_name) {
3222       return false;
3223     }
3224     // Check that package_from_class_name() returns null, not "", if there is no package.
3225     assert(other_pkg == nullptr || other_pkg->utf8_length() > 0, "package name is empty string");
3226 
3227     const Symbol* const this_package_name =
3228       this->package() != nullptr ? this->package()->name() : nullptr;
3229 
3230     if (this_package_name == nullptr || other_pkg == nullptr) {
3231       // One of the two doesn't have a package.  Only return true if the other
3232       // one also doesn't have a package.
3233       return this_package_name == other_pkg;
3234     }
3235 
3236     // Check if package is identical
3237     return this_package_name->fast_compare(other_pkg) == 0;
3238   }
3239 }
3240 
3241 static bool is_prohibited_package_slow(Symbol* class_name) {
3242   // Caller has ResourceMark
3243   int length;
3244   jchar* unicode = class_name->as_unicode(length);
3245   return (length >= 5 &&
3246           unicode[0] == 'j' &&
3247           unicode[1] == 'a' &&
3248           unicode[2] == 'v' &&
3249           unicode[3] == 'a' &&
3250           unicode[4] == '/');
3251 }
3252 
3253 // Only boot and platform class loaders can define classes in "java/" packages.
3254 void InstanceKlass::check_prohibited_package(Symbol* class_name,
3255                                              ClassLoaderData* loader_data,
3256                                              TRAPS) {
3257   if (!loader_data->is_boot_class_loader_data() &&
3258       !loader_data->is_platform_class_loader_data() &&
3259       class_name != nullptr && class_name->utf8_length() >= 5) {
3260     ResourceMark rm(THREAD);
3261     bool prohibited;
3262     const u1* base = class_name->base();
3263     if ((base[0] | base[1] | base[2] | base[3] | base[4]) & 0x80) {
3264       prohibited = is_prohibited_package_slow(class_name);
3265     } else {
3266       char* name = class_name->as_C_string();
3267       prohibited = (strncmp(name, JAVAPKG, JAVAPKG_LEN) == 0 && name[JAVAPKG_LEN] == '/');
3268     }
3269     if (prohibited) {
3270       TempNewSymbol pkg_name = ClassLoader::package_from_class_name(class_name);
3271       assert(pkg_name != nullptr, "Error in parsing package name starting with 'java/'");
3272       char* name = pkg_name->as_C_string();
3273       const char* class_loader_name = loader_data->loader_name_and_id();
3274       StringUtils::replace_no_expand(name, "/", ".");
3275       const char* msg_text1 = "Class loader (instance of): ";
3276       const char* msg_text2 = " tried to load prohibited package name: ";
3277       size_t len = strlen(msg_text1) + strlen(class_loader_name) + strlen(msg_text2) + strlen(name) + 1;
3278       char* message = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, len);
3279       jio_snprintf(message, len, "%s%s%s%s", msg_text1, class_loader_name, msg_text2, name);
3280       THROW_MSG(vmSymbols::java_lang_SecurityException(), message);
3281     }
3282   }
3283   return;
3284 }
3285 
3286 bool InstanceKlass::find_inner_classes_attr(int* ooff, int* noff, TRAPS) const {
3287   constantPoolHandle i_cp(THREAD, constants());
3288   for (InnerClassesIterator iter(this); !iter.done(); iter.next()) {
3289     int ioff = iter.inner_class_info_index();
3290     if (ioff != 0) {
3291       // Check to see if the name matches the class we're looking for
3292       // before attempting to find the class.
3293       if (i_cp->klass_name_at_matches(this, ioff)) {
3294         Klass* inner_klass = i_cp->klass_at(ioff, CHECK_false);
3295         if (this == inner_klass) {
3296           *ooff = iter.outer_class_info_index();
3297           *noff = iter.inner_name_index();
3298           return true;
3299         }
3300       }
3301     }
3302   }
3303   return false;
3304 }
3305 
3306 InstanceKlass* InstanceKlass::compute_enclosing_class(bool* inner_is_member, TRAPS) const {
3307   InstanceKlass* outer_klass = nullptr;
3308   *inner_is_member = false;
3309   int ooff = 0, noff = 0;
3310   bool has_inner_classes_attr = find_inner_classes_attr(&ooff, &noff, THREAD);
3311   if (has_inner_classes_attr) {
3312     constantPoolHandle i_cp(THREAD, constants());
3313     if (ooff != 0) {
3314       Klass* ok = i_cp->klass_at(ooff, CHECK_NULL);
3315       if (!ok->is_instance_klass()) {
3316         // If the outer class is not an instance klass then it cannot have
3317         // declared any inner classes.
3318         ResourceMark rm(THREAD);
3319         // Names are all known to be < 64k so we know this formatted message is not excessively large.
3320         Exceptions::fthrow(
3321           THREAD_AND_LOCATION,
3322           vmSymbols::java_lang_IncompatibleClassChangeError(),
3323           "%s and %s disagree on InnerClasses attribute",
3324           ok->external_name(),
3325           external_name());
3326         return nullptr;
3327       }
3328       outer_klass = InstanceKlass::cast(ok);
3329       *inner_is_member = true;
3330     }
3331     if (nullptr == outer_klass) {
3332       // It may be a local class; try for that.
3333       int encl_method_class_idx = enclosing_method_class_index();
3334       if (encl_method_class_idx != 0) {
3335         Klass* ok = i_cp->klass_at(encl_method_class_idx, CHECK_NULL);
3336         outer_klass = InstanceKlass::cast(ok);
3337         *inner_is_member = false;
3338       }
3339     }
3340   }
3341 
3342   // If no inner class attribute found for this class.
3343   if (nullptr == outer_klass) return nullptr;
3344 
3345   // Throws an exception if outer klass has not declared k as an inner klass
3346   // We need evidence that each klass knows about the other, or else
3347   // the system could allow a spoof of an inner class to gain access rights.
3348   Reflection::check_for_inner_class(outer_klass, this, *inner_is_member, CHECK_NULL);
3349   return outer_klass;
3350 }
3351 
3352 u2 InstanceKlass::compute_modifier_flags() const {
3353   u2 access = access_flags().as_unsigned_short();
3354 
3355   // But check if it happens to be member class.
3356   InnerClassesIterator iter(this);
3357   for (; !iter.done(); iter.next()) {
3358     int ioff = iter.inner_class_info_index();
3359     // Inner class attribute can be zero, skip it.
3360     // Strange but true:  JVM spec. allows null inner class refs.
3361     if (ioff == 0) continue;
3362 
3363     // only look at classes that are already loaded
3364     // since we are looking for the flags for our self.
3365     Symbol* inner_name = constants()->klass_name_at(ioff);
3366     if (name() == inner_name) {
3367       // This is really a member class.
3368       access = iter.inner_access_flags();
3369       break;
3370     }
3371   }
3372   // Remember to strip ACC_SUPER bit
3373   return (access & (~JVM_ACC_SUPER));
3374 }
3375 
3376 jint InstanceKlass::jvmti_class_status() const {
3377   jint result = 0;
3378 
3379   if (is_linked()) {
3380     result |= JVMTI_CLASS_STATUS_VERIFIED | JVMTI_CLASS_STATUS_PREPARED;
3381   }
3382 
3383   if (is_initialized()) {
3384     assert(is_linked(), "Class status is not consistent");
3385     result |= JVMTI_CLASS_STATUS_INITIALIZED;
3386   }
3387   if (is_in_error_state()) {
3388     result |= JVMTI_CLASS_STATUS_ERROR;
3389   }
3390   return result;
3391 }
3392 
3393 Method* InstanceKlass::method_at_itable(InstanceKlass* holder, int index, TRAPS) {
3394   bool implements_interface; // initialized by method_at_itable_or_null
3395   Method* m = method_at_itable_or_null(holder, index,
3396                                        implements_interface); // out parameter
3397   if (m != nullptr) {
3398     assert(implements_interface, "sanity");
3399     return m;
3400   } else if (implements_interface) {
3401     // Throw AbstractMethodError since corresponding itable slot is empty.
3402     THROW_NULL(vmSymbols::java_lang_AbstractMethodError());
3403   } else {
3404     // If the interface isn't implemented by the receiver class,
3405     // the VM should throw IncompatibleClassChangeError.
3406     ResourceMark rm(THREAD);
3407     stringStream ss;
3408     bool same_module = (module() == holder->module());
3409     ss.print("Receiver class %s does not implement "
3410              "the interface %s defining the method to be called "
3411              "(%s%s%s)",
3412              external_name(), holder->external_name(),
3413              (same_module) ? joint_in_module_of_loader(holder) : class_in_module_of_loader(),
3414              (same_module) ? "" : "; ",
3415              (same_module) ? "" : holder->class_in_module_of_loader());
3416     THROW_MSG_NULL(vmSymbols::java_lang_IncompatibleClassChangeError(), ss.as_string());
3417   }
3418 }
3419 
3420 Method* InstanceKlass::method_at_itable_or_null(InstanceKlass* holder, int index, bool& implements_interface) {
3421   klassItable itable(this);
3422   for (int i = 0; i < itable.size_offset_table(); i++) {
3423     itableOffsetEntry* offset_entry = itable.offset_entry(i);
3424     if (offset_entry->interface_klass() == holder) {
3425       implements_interface = true;
3426       itableMethodEntry* ime = offset_entry->first_method_entry(this);
3427       Method* m = ime[index].method();
3428       return m;
3429     }
3430   }
3431   implements_interface = false;
3432   return nullptr; // offset entry not found
3433 }
3434 
3435 int InstanceKlass::vtable_index_of_interface_method(Method* intf_method) {
3436   assert(is_linked(), "required");
3437   assert(intf_method->method_holder()->is_interface(), "not an interface method");
3438   assert(is_subtype_of(intf_method->method_holder()), "interface not implemented");
3439 
3440   int vtable_index = Method::invalid_vtable_index;
3441   Symbol* name = intf_method->name();
3442   Symbol* signature = intf_method->signature();
3443 
3444   // First check in default method array
3445   if (!intf_method->is_abstract() && default_methods() != nullptr) {
3446     int index = find_method_index(default_methods(),
3447                                   name, signature,
3448                                   Klass::OverpassLookupMode::find,
3449                                   Klass::StaticLookupMode::find,
3450                                   Klass::PrivateLookupMode::find);
3451     if (index >= 0) {
3452       vtable_index = default_vtable_indices()->at(index);
3453     }
3454   }
3455   if (vtable_index == Method::invalid_vtable_index) {
3456     // get vtable_index for miranda methods
3457     klassVtable vt = vtable();
3458     vtable_index = vt.index_of_miranda(name, signature);
3459   }
3460   return vtable_index;
3461 }
3462 
3463 #if INCLUDE_JVMTI
3464 // update default_methods for redefineclasses for methods that are
3465 // not yet in the vtable due to concurrent subclass define and superinterface
3466 // redefinition
3467 // Note: those in the vtable, should have been updated via adjust_method_entries
3468 void InstanceKlass::adjust_default_methods(bool* trace_name_printed) {
3469   // search the default_methods for uses of either obsolete or EMCP methods
3470   if (default_methods() != nullptr) {
3471     for (int index = 0; index < default_methods()->length(); index ++) {
3472       Method* old_method = default_methods()->at(index);
3473       if (old_method == nullptr || !old_method->is_old()) {
3474         continue; // skip uninteresting entries
3475       }
3476       assert(!old_method->is_deleted(), "default methods may not be deleted");
3477       Method* new_method = old_method->get_new_method();
3478       default_methods()->at_put(index, new_method);
3479 
3480       if (log_is_enabled(Info, redefine, class, update)) {
3481         ResourceMark rm;
3482         if (!(*trace_name_printed)) {
3483           log_info(redefine, class, update)
3484             ("adjust: klassname=%s default methods from name=%s",
3485              external_name(), old_method->method_holder()->external_name());
3486           *trace_name_printed = true;
3487         }
3488         log_debug(redefine, class, update, vtables)
3489           ("default method update: %s(%s) ",
3490            new_method->name()->as_C_string(), new_method->signature()->as_C_string());
3491       }
3492     }
3493   }
3494 }
3495 #endif // INCLUDE_JVMTI
3496 
3497 // On-stack replacement stuff
3498 void InstanceKlass::add_osr_nmethod(nmethod* n) {
3499   assert_lock_strong(NMethodState_lock);
3500 #ifndef PRODUCT
3501   nmethod* prev = lookup_osr_nmethod(n->method(), n->osr_entry_bci(), n->comp_level(), true);
3502   assert(prev == nullptr || !prev->is_in_use() COMPILER2_PRESENT(|| StressRecompilation),
3503       "redundant OSR recompilation detected. memory leak in CodeCache!");
3504 #endif
3505   // only one compilation can be active
3506   assert(n->is_osr_method(), "wrong kind of nmethod");
3507   n->set_osr_link(osr_nmethods_head());
3508   set_osr_nmethods_head(n);
3509   // Raise the highest osr level if necessary
3510   n->method()->set_highest_osr_comp_level(MAX2(n->method()->highest_osr_comp_level(), n->comp_level()));
3511 
3512   // Get rid of the osr methods for the same bci that have lower levels.
3513   for (int l = CompLevel_limited_profile; l < n->comp_level(); l++) {
3514     nmethod *inv = lookup_osr_nmethod(n->method(), n->osr_entry_bci(), l, true);
3515     if (inv != nullptr && inv->is_in_use()) {
3516       inv->make_not_entrant(nmethod::InvalidationReason::OSR_INVALIDATION_OF_LOWER_LEVEL);
3517     }
3518   }
3519 }
3520 
3521 // Remove osr nmethod from the list. Return true if found and removed.
3522 bool InstanceKlass::remove_osr_nmethod(nmethod* n) {
3523   // This is a short non-blocking critical region, so the no safepoint check is ok.
3524   ConditionalMutexLocker ml(NMethodState_lock, !NMethodState_lock->owned_by_self(), Mutex::_no_safepoint_check_flag);
3525   assert(n->is_osr_method(), "wrong kind of nmethod");
3526   nmethod* last = nullptr;
3527   nmethod* cur  = osr_nmethods_head();
3528   int max_level = CompLevel_none;  // Find the max comp level excluding n
3529   Method* m = n->method();
3530   // Search for match
3531   bool found = false;
3532   while(cur != nullptr && cur != n) {
3533     if (m == cur->method()) {
3534       // Find max level before n
3535       max_level = MAX2(max_level, cur->comp_level());
3536     }
3537     last = cur;
3538     cur = cur->osr_link();
3539   }
3540   nmethod* next = nullptr;
3541   if (cur == n) {
3542     found = true;
3543     next = cur->osr_link();
3544     if (last == nullptr) {
3545       // Remove first element
3546       set_osr_nmethods_head(next);
3547     } else {
3548       last->set_osr_link(next);
3549     }
3550   }
3551   n->set_osr_link(nullptr);
3552   cur = next;
3553   while (cur != nullptr) {
3554     // Find max level after n
3555     if (m == cur->method()) {
3556       max_level = MAX2(max_level, cur->comp_level());
3557     }
3558     cur = cur->osr_link();
3559   }
3560   m->set_highest_osr_comp_level(max_level);
3561   return found;
3562 }
3563 
3564 int InstanceKlass::mark_osr_nmethods(DeoptimizationScope* deopt_scope, const Method* m) {
3565   ConditionalMutexLocker ml(NMethodState_lock, !NMethodState_lock->owned_by_self(), Mutex::_no_safepoint_check_flag);
3566   nmethod* osr = osr_nmethods_head();
3567   int found = 0;
3568   while (osr != nullptr) {
3569     assert(osr->is_osr_method(), "wrong kind of nmethod found in chain");
3570     if (osr->method() == m) {
3571       deopt_scope->mark(osr);
3572       found++;
3573     }
3574     osr = osr->osr_link();
3575   }
3576   return found;
3577 }
3578 
3579 nmethod* InstanceKlass::lookup_osr_nmethod(const Method* m, int bci, int comp_level, bool match_level) const {
3580   ConditionalMutexLocker ml(NMethodState_lock, !NMethodState_lock->owned_by_self(), Mutex::_no_safepoint_check_flag);
3581   nmethod* osr = osr_nmethods_head();
3582   nmethod* best = nullptr;
3583   while (osr != nullptr) {
3584     assert(osr->is_osr_method(), "wrong kind of nmethod found in chain");
3585     // There can be a time when a c1 osr method exists but we are waiting
3586     // for a c2 version. When c2 completes its osr nmethod we will trash
3587     // the c1 version and only be able to find the c2 version. However
3588     // while we overflow in the c1 code at back branches we don't want to
3589     // try and switch to the same code as we are already running
3590 
3591     if (osr->method() == m &&
3592         (bci == InvocationEntryBci || osr->osr_entry_bci() == bci)) {
3593       if (match_level) {
3594         if (osr->comp_level() == comp_level) {
3595           // Found a match - return it.
3596           return osr;
3597         }
3598       } else {
3599         if (best == nullptr || (osr->comp_level() > best->comp_level())) {
3600           if (osr->comp_level() == CompilationPolicy::highest_compile_level()) {
3601             // Found the best possible - return it.
3602             return osr;
3603           }
3604           best = osr;
3605         }
3606       }
3607     }
3608     osr = osr->osr_link();
3609   }
3610 
3611   assert(match_level == false || best == nullptr, "shouldn't pick up anything if match_level is set");
3612   if (best != nullptr && best->comp_level() >= comp_level) {
3613     return best;
3614   }
3615   return nullptr;
3616 }
3617 
3618 // -----------------------------------------------------------------------------------------------------
3619 // Printing
3620 
3621 #define BULLET  " - "
3622 
3623 static const char* state_names[] = {
3624   "allocated", "loaded", "linked", "being_initialized", "fully_initialized", "initialization_error"
3625 };
3626 
3627 static void print_vtable(intptr_t* start, int len, outputStream* st) {
3628   for (int i = 0; i < len; i++) {
3629     intptr_t e = start[i];
3630     st->print("%d : " INTPTR_FORMAT, i, e);
3631     if (MetaspaceObj::is_valid((Metadata*)e)) {
3632       st->print(" ");
3633       ((Metadata*)e)->print_value_on(st);
3634     }
3635     st->cr();
3636   }
3637 }
3638 
3639 static void print_vtable(vtableEntry* start, int len, outputStream* st) {
3640   return print_vtable(reinterpret_cast<intptr_t*>(start), len, st);
3641 }
3642 
3643 const char* InstanceKlass::init_state_name() const {
3644   return state_names[init_state()];
3645 }
3646 
3647 void InstanceKlass::print_on(outputStream* st) const {
3648   assert(is_klass(), "must be klass");
3649   Klass::print_on(st);
3650 
3651   st->print(BULLET"instance size:     %d", size_helper());                        st->cr();
3652   st->print(BULLET"klass size:        %d", size());                               st->cr();
3653   st->print(BULLET"access:            "); access_flags().print_on(st);            st->cr();
3654   st->print(BULLET"flags:             "); _misc_flags.print_on(st);               st->cr();
3655   st->print(BULLET"state:             "); st->print_cr("%s", init_state_name());
3656   st->print(BULLET"name:              "); name()->print_value_on(st);             st->cr();
3657   st->print(BULLET"super:             "); Metadata::print_value_on_maybe_null(st, super()); st->cr();
3658   st->print(BULLET"sub:               ");
3659   Klass* sub = subklass();
3660   int n;
3661   for (n = 0; sub != nullptr; n++, sub = sub->next_sibling()) {
3662     if (n < MaxSubklassPrintSize) {
3663       sub->print_value_on(st);
3664       st->print("   ");
3665     }
3666   }
3667   if (n >= MaxSubklassPrintSize) st->print("(%zd more klasses...)", n - MaxSubklassPrintSize);
3668   st->cr();
3669 
3670   if (is_interface()) {
3671     st->print_cr(BULLET"nof implementors:  %d", nof_implementors());
3672     if (nof_implementors() == 1) {
3673       st->print_cr(BULLET"implementor:    ");
3674       st->print("   ");
3675       implementor()->print_value_on(st);
3676       st->cr();
3677     }
3678   }
3679 
3680   st->print(BULLET"arrays:            "); Metadata::print_value_on_maybe_null(st, array_klasses()); st->cr();
3681   st->print(BULLET"methods:           "); methods()->print_value_on(st);               st->cr();
3682   if (Verbose || WizardMode) {
3683     Array<Method*>* method_array = methods();
3684     for (int i = 0; i < method_array->length(); i++) {
3685       st->print("%d : ", i); method_array->at(i)->print_value(); st->cr();
3686     }
3687   }
3688   st->print(BULLET"method ordering:   "); method_ordering()->print_value_on(st);      st->cr();
3689   if (default_methods() != nullptr) {
3690     st->print(BULLET"default_methods:   "); default_methods()->print_value_on(st);    st->cr();
3691     if (Verbose) {
3692       Array<Method*>* method_array = default_methods();
3693       for (int i = 0; i < method_array->length(); i++) {
3694         st->print("%d : ", i); method_array->at(i)->print_value(); st->cr();
3695       }
3696     }
3697   }
3698   print_on_maybe_null(st, BULLET"default vtable indices:   ", default_vtable_indices());
3699   st->print(BULLET"local interfaces:  "); local_interfaces()->print_value_on(st);      st->cr();
3700   st->print(BULLET"trans. interfaces: "); transitive_interfaces()->print_value_on(st); st->cr();
3701 
3702   st->print(BULLET"secondary supers: "); secondary_supers()->print_value_on(st); st->cr();
3703 
3704   st->print(BULLET"hash_slot:         %d", hash_slot()); st->cr();
3705   st->print(BULLET"secondary bitmap: " UINTX_FORMAT_X_0, _secondary_supers_bitmap); st->cr();
3706 
3707   if (secondary_supers() != nullptr) {
3708     if (Verbose) {
3709       bool is_hashed = (_secondary_supers_bitmap != SECONDARY_SUPERS_BITMAP_FULL);
3710       st->print_cr(BULLET"---- secondary supers (%d words):", _secondary_supers->length());
3711       for (int i = 0; i < _secondary_supers->length(); i++) {
3712         ResourceMark rm; // for external_name()
3713         Klass* secondary_super = _secondary_supers->at(i);
3714         st->print(BULLET"%2d:", i);
3715         if (is_hashed) {
3716           int home_slot = compute_home_slot(secondary_super, _secondary_supers_bitmap);
3717           int distance = (i - home_slot) & SECONDARY_SUPERS_TABLE_MASK;
3718           st->print(" dist:%02d:", distance);
3719         }
3720         st->print_cr(" %p %s", secondary_super, secondary_super->external_name());
3721       }
3722     }
3723   }
3724   st->print(BULLET"constants:         "); constants()->print_value_on(st);         st->cr();
3725 
3726   print_on_maybe_null(st, BULLET"class loader data:  ", class_loader_data());
3727   print_on_maybe_null(st, BULLET"source file:       ", source_file_name());
3728   if (source_debug_extension() != nullptr) {
3729     st->print(BULLET"source debug extension:       ");
3730     st->print("%s", source_debug_extension());
3731     st->cr();
3732   }
3733   print_on_maybe_null(st, BULLET"class annotations:       ", class_annotations());
3734   print_on_maybe_null(st, BULLET"class type annotations:  ", class_type_annotations());
3735   print_on_maybe_null(st, BULLET"field annotations:       ", fields_annotations());
3736   print_on_maybe_null(st, BULLET"field type annotations:  ", fields_type_annotations());
3737   {
3738     bool have_pv = false;
3739     // previous versions are linked together through the InstanceKlass
3740     for (InstanceKlass* pv_node = previous_versions();
3741          pv_node != nullptr;
3742          pv_node = pv_node->previous_versions()) {
3743       if (!have_pv)
3744         st->print(BULLET"previous version:  ");
3745       have_pv = true;
3746       pv_node->constants()->print_value_on(st);
3747     }
3748     if (have_pv) st->cr();
3749   }
3750 
3751   print_on_maybe_null(st, BULLET"generic signature: ", generic_signature());
3752   st->print(BULLET"inner classes:     "); inner_classes()->print_value_on(st);     st->cr();
3753   st->print(BULLET"nest members:     "); nest_members()->print_value_on(st);     st->cr();
3754   print_on_maybe_null(st, BULLET"record components:     ", record_components());
3755   st->print(BULLET"permitted subclasses:     "); permitted_subclasses()->print_value_on(st);     st->cr();
3756   if (java_mirror() != nullptr) {
3757     st->print(BULLET"java mirror:       ");
3758     java_mirror()->print_value_on(st);
3759     st->cr();
3760   } else {
3761     st->print_cr(BULLET"java mirror:       null");
3762   }
3763   st->print(BULLET"vtable length      %d  (start addr: " PTR_FORMAT ")", vtable_length(), p2i(start_of_vtable())); st->cr();
3764   if (vtable_length() > 0 && (Verbose || WizardMode))  print_vtable(start_of_vtable(), vtable_length(), st);
3765   st->print(BULLET"itable length      %d (start addr: " PTR_FORMAT ")", itable_length(), p2i(start_of_itable())); st->cr();
3766   if (itable_length() > 0 && (Verbose || WizardMode))  print_vtable(start_of_itable(), itable_length(), st);
3767   st->print_cr(BULLET"---- static fields (%d words):", static_field_size());
3768 
3769   FieldPrinter print_static_field(st);
3770   ((InstanceKlass*)this)->do_local_static_fields(&print_static_field);
3771   st->print_cr(BULLET"---- non-static fields (%d words):", nonstatic_field_size());
3772   FieldPrinter print_nonstatic_field(st);
3773   InstanceKlass* ik = const_cast<InstanceKlass*>(this);
3774   ik->print_nonstatic_fields(&print_nonstatic_field);
3775 
3776   st->print(BULLET"non-static oop maps (%d entries): ", nonstatic_oop_map_count());
3777   OopMapBlock* map     = start_of_nonstatic_oop_maps();
3778   OopMapBlock* end_map = map + nonstatic_oop_map_count();
3779   while (map < end_map) {
3780     st->print("%d-%d ", map->offset(), map->offset() + heapOopSize*(map->count() - 1));
3781     map++;
3782   }
3783   st->cr();
3784 
3785   if (fieldinfo_search_table() != nullptr) {
3786     st->print_cr(BULLET"---- field info search table:");
3787     FieldInfoStream::print_search_table(st, _constants, _fieldinfo_stream, _fieldinfo_search_table);
3788   }
3789 }
3790 
3791 void InstanceKlass::print_value_on(outputStream* st) const {
3792   assert(is_klass(), "must be klass");
3793   if (Verbose || WizardMode)  access_flags().print_on(st);
3794   name()->print_value_on(st);
3795 }
3796 
3797 void FieldPrinter::do_field(fieldDescriptor* fd) {
3798   _st->print(BULLET);
3799    if (_obj == nullptr) {
3800      fd->print_on(_st);
3801      _st->cr();
3802    } else {
3803      fd->print_on_for(_st, _obj);
3804      _st->cr();
3805    }
3806 }
3807 
3808 
3809 void InstanceKlass::oop_print_on(oop obj, outputStream* st) {
3810   Klass::oop_print_on(obj, st);
3811 
3812   if (this == vmClasses::String_klass()) {
3813     typeArrayOop value  = java_lang_String::value(obj);
3814     juint        length = java_lang_String::length(obj);
3815     if (value != nullptr &&
3816         value->is_typeArray() &&
3817         length <= (juint) value->length()) {
3818       st->print(BULLET"string: ");
3819       java_lang_String::print(obj, st);
3820       st->cr();
3821     }
3822   }
3823 
3824   st->print_cr(BULLET"---- fields (total size %zu words):", oop_size(obj));
3825   FieldPrinter print_field(st, obj);
3826   print_nonstatic_fields(&print_field);
3827 
3828   if (this == vmClasses::Class_klass()) {
3829     st->print(BULLET"signature: ");
3830     java_lang_Class::print_signature(obj, st);
3831     st->cr();
3832     Klass* real_klass = java_lang_Class::as_Klass(obj);
3833     if (real_klass != nullptr && real_klass->is_instance_klass()) {
3834       st->print_cr(BULLET"---- static fields (%d):", java_lang_Class::static_oop_field_count(obj));
3835       InstanceKlass::cast(real_klass)->do_local_static_fields(&print_field);
3836     }
3837   } else if (this == vmClasses::MethodType_klass()) {
3838     st->print(BULLET"signature: ");
3839     java_lang_invoke_MethodType::print_signature(obj, st);
3840     st->cr();
3841   }
3842 }
3843 
3844 #ifndef PRODUCT
3845 
3846 bool InstanceKlass::verify_itable_index(int i) {
3847   int method_count = klassItable::method_count_for_interface(this);
3848   assert(i >= 0 && i < method_count, "index out of bounds");
3849   return true;
3850 }
3851 
3852 #endif //PRODUCT
3853 
3854 void InstanceKlass::oop_print_value_on(oop obj, outputStream* st) {
3855   st->print("a ");
3856   name()->print_value_on(st);
3857   obj->print_address_on(st);
3858   if (this == vmClasses::String_klass()
3859       && java_lang_String::value(obj) != nullptr) {
3860     ResourceMark rm;
3861     int len = java_lang_String::length(obj);
3862     int plen = (len < 24 ? len : 12);
3863     char* str = java_lang_String::as_utf8_string(obj, 0, plen);
3864     st->print(" = \"%s\"", str);
3865     if (len > plen)
3866       st->print("...[%d]", len);
3867   } else if (this == vmClasses::Class_klass()) {
3868     Klass* k = java_lang_Class::as_Klass(obj);
3869     st->print(" = ");
3870     if (k != nullptr) {
3871       k->print_value_on(st);
3872     } else {
3873       const char* tname = type2name(java_lang_Class::primitive_type(obj));
3874       st->print("%s", tname ? tname : "type?");
3875     }
3876   } else if (this == vmClasses::MethodType_klass()) {
3877     st->print(" = ");
3878     java_lang_invoke_MethodType::print_signature(obj, st);
3879   } else if (java_lang_boxing_object::is_instance(obj)) {
3880     st->print(" = ");
3881     java_lang_boxing_object::print(obj, st);
3882   } else if (this == vmClasses::LambdaForm_klass()) {
3883     oop vmentry = java_lang_invoke_LambdaForm::vmentry(obj);
3884     if (vmentry != nullptr) {
3885       st->print(" => ");
3886       vmentry->print_value_on(st);
3887     }
3888   } else if (this == vmClasses::MemberName_klass()) {
3889     Metadata* vmtarget = java_lang_invoke_MemberName::vmtarget(obj);
3890     if (vmtarget != nullptr) {
3891       st->print(" = ");
3892       vmtarget->print_value_on(st);
3893     } else {
3894       oop clazz = java_lang_invoke_MemberName::clazz(obj);
3895       oop name  = java_lang_invoke_MemberName::name(obj);
3896       if (clazz != nullptr) {
3897         clazz->print_value_on(st);
3898       } else {
3899         st->print("null");
3900       }
3901       st->print(".");
3902       if (name != nullptr) {
3903         name->print_value_on(st);
3904       } else {
3905         st->print("null");
3906       }
3907     }
3908   }
3909 }
3910 
3911 const char* InstanceKlass::internal_name() const {
3912   return external_name();
3913 }
3914 
3915 void InstanceKlass::print_class_load_logging(ClassLoaderData* loader_data,
3916                                              const ModuleEntry* module_entry,
3917                                              const ClassFileStream* cfs) const {
3918 
3919   if (ClassListWriter::is_enabled()) {
3920     ClassListWriter::write(this, cfs);
3921   }
3922 
3923   print_class_load_helper(loader_data, module_entry, cfs);
3924   print_class_load_cause_logging();
3925 }
3926 
3927 void InstanceKlass::print_class_load_helper(ClassLoaderData* loader_data,
3928                                              const ModuleEntry* module_entry,
3929                                              const ClassFileStream* cfs) const {
3930 
3931   if (!log_is_enabled(Info, class, load)) {
3932     return;
3933   }
3934 
3935   ResourceMark rm;
3936   LogMessage(class, load) msg;
3937   stringStream info_stream;
3938 
3939   // Name and class hierarchy info
3940   info_stream.print("%s", external_name());
3941 
3942   // Source
3943   if (cfs != nullptr) {
3944     if (cfs->source() != nullptr) {
3945       const char* module_name = (module_entry->name() == nullptr) ? UNNAMED_MODULE : module_entry->name()->as_C_string();
3946       if (module_name != nullptr) {
3947         // When the boot loader created the stream, it didn't know the module name
3948         // yet. Let's format it now.
3949         if (cfs->from_boot_loader_modules_image()) {
3950           info_stream.print(" source: jrt:/%s", module_name);
3951         } else {
3952           info_stream.print(" source: %s", cfs->source());
3953         }
3954       } else {
3955         info_stream.print(" source: %s", cfs->source());
3956       }
3957     } else if (loader_data == ClassLoaderData::the_null_class_loader_data()) {
3958       Thread* current = Thread::current();
3959       Klass* caller = current->is_Java_thread() ?
3960         JavaThread::cast(current)->security_get_caller_class(1):
3961         nullptr;
3962       // caller can be null, for example, during a JVMTI VM_Init hook
3963       if (caller != nullptr) {
3964         info_stream.print(" source: instance of %s", caller->external_name());
3965       } else {
3966         // source is unknown
3967       }
3968     } else {
3969       oop class_loader = loader_data->class_loader();
3970       info_stream.print(" source: %s", class_loader->klass()->external_name());
3971     }
3972   } else {
3973     assert(this->in_aot_cache(), "must be");
3974     if (AOTMetaspace::in_aot_cache_dynamic_region((void*)this)) {
3975       info_stream.print(" source: shared objects file (top)");
3976     } else {
3977       info_stream.print(" source: shared objects file");
3978     }
3979   }
3980 
3981   msg.info("%s", info_stream.as_string());
3982 
3983   if (log_is_enabled(Debug, class, load)) {
3984     stringStream debug_stream;
3985 
3986     // Class hierarchy info
3987     debug_stream.print(" klass: " PTR_FORMAT " super: " PTR_FORMAT,
3988                        p2i(this),  p2i(super()));
3989 
3990     // Interfaces
3991     if (local_interfaces() != nullptr && local_interfaces()->length() > 0) {
3992       debug_stream.print(" interfaces:");
3993       int length = local_interfaces()->length();
3994       for (int i = 0; i < length; i++) {
3995         debug_stream.print(" " PTR_FORMAT,
3996                            p2i(local_interfaces()->at(i)));
3997       }
3998     }
3999 
4000     // Class loader
4001     debug_stream.print(" loader: [");
4002     loader_data->print_value_on(&debug_stream);
4003     debug_stream.print("]");
4004 
4005     // Classfile checksum
4006     if (cfs) {
4007       debug_stream.print(" bytes: %d checksum: %08x",
4008                          cfs->length(),
4009                          ClassLoader::crc32(0, (const char*)cfs->buffer(),
4010                          cfs->length()));
4011     }
4012 
4013     msg.debug("%s", debug_stream.as_string());
4014   }
4015 }
4016 
4017 void InstanceKlass::print_class_load_cause_logging() const {
4018   bool log_cause_native = log_is_enabled(Info, class, load, cause, native);
4019   if (log_cause_native || log_is_enabled(Info, class, load, cause)) {
4020     JavaThread* current = JavaThread::current();
4021     ResourceMark rm(current);
4022     const char* name = external_name();
4023 
4024     if (LogClassLoadingCauseFor == nullptr ||
4025         (strcmp("*", LogClassLoadingCauseFor) != 0 &&
4026          strstr(name, LogClassLoadingCauseFor) == nullptr)) {
4027         return;
4028     }
4029 
4030     // Log Java stack first
4031     {
4032       LogMessage(class, load, cause) msg;
4033       NonInterleavingLogStream info_stream{LogLevelType::Info, msg};
4034 
4035       info_stream.print_cr("Java stack when loading %s:", name);
4036       current->print_stack_on(&info_stream);
4037     }
4038 
4039     // Log native stack second
4040     if (log_cause_native) {
4041       // Log to string first so that lines can be indented
4042       stringStream stack_stream;
4043       char buf[O_BUFLEN];
4044       address lastpc = nullptr;
4045       NativeStackPrinter nsp(current);
4046       nsp.print_stack(&stack_stream, buf, sizeof(buf), lastpc,
4047                       true /* print_source_info */, -1 /* max stack */);
4048 
4049       LogMessage(class, load, cause, native) msg;
4050       NonInterleavingLogStream info_stream{LogLevelType::Info, msg};
4051       info_stream.print_cr("Native stack when loading %s:", name);
4052 
4053       // Print each native stack line to the log
4054       int size = (int) stack_stream.size();
4055       char* stack = stack_stream.as_string();
4056       char* stack_end = stack + size;
4057       char* line_start = stack;
4058       for (char* p = stack; p < stack_end; p++) {
4059         if (*p == '\n') {
4060           *p = '\0';
4061           info_stream.print_cr("\t%s", line_start);
4062           line_start = p + 1;
4063         }
4064       }
4065       if (line_start < stack_end) {
4066         info_stream.print_cr("\t%s", line_start);
4067       }
4068     }
4069   }
4070 }
4071 
4072 // Verification
4073 
4074 class VerifyFieldClosure: public BasicOopIterateClosure {
4075  protected:
4076   template <class T> void do_oop_work(T* p) {
4077     oop obj = RawAccess<>::oop_load(p);
4078     if (!oopDesc::is_oop_or_null(obj)) {
4079       tty->print_cr("Failed: " PTR_FORMAT " -> " PTR_FORMAT, p2i(p), p2i(obj));
4080       Universe::print_on(tty);
4081       guarantee(false, "boom");
4082     }
4083   }
4084  public:
4085   virtual void do_oop(oop* p)       { VerifyFieldClosure::do_oop_work(p); }
4086   virtual void do_oop(narrowOop* p) { VerifyFieldClosure::do_oop_work(p); }
4087 };
4088 
4089 void InstanceKlass::verify_on(outputStream* st) {
4090 #ifndef PRODUCT
4091   // Avoid redundant verifies, this really should be in product.
4092   if (_verify_count == Universe::verify_count()) return;
4093   _verify_count = Universe::verify_count();
4094 #endif
4095 
4096   // Verify Klass
4097   Klass::verify_on(st);
4098 
4099   // Verify that klass is present in ClassLoaderData
4100   guarantee(class_loader_data()->contains_klass(this),
4101             "this class isn't found in class loader data");
4102 
4103   // Verify vtables
4104   if (is_linked()) {
4105     // $$$ This used to be done only for m/s collections.  Doing it
4106     // always seemed a valid generalization.  (DLD -- 6/00)
4107     vtable().verify(st);
4108   }
4109 
4110   // Verify first subklass
4111   if (subklass() != nullptr) {
4112     guarantee(subklass()->is_klass(), "should be klass");
4113   }
4114 
4115   // Verify siblings
4116   Klass* super = this->super();
4117   Klass* sib = next_sibling();
4118   if (sib != nullptr) {
4119     if (sib == this) {
4120       fatal("subclass points to itself " PTR_FORMAT, p2i(sib));
4121     }
4122 
4123     guarantee(sib->is_klass(), "should be klass");
4124     guarantee(sib->super() == super, "siblings should have same superklass");
4125   }
4126 
4127   // Verify local interfaces
4128   if (local_interfaces()) {
4129     Array<InstanceKlass*>* local_interfaces = this->local_interfaces();
4130     for (int j = 0; j < local_interfaces->length(); j++) {
4131       InstanceKlass* e = local_interfaces->at(j);
4132       guarantee(e->is_klass() && e->is_interface(), "invalid local interface");
4133     }
4134   }
4135 
4136   // Verify transitive interfaces
4137   if (transitive_interfaces() != nullptr) {
4138     Array<InstanceKlass*>* transitive_interfaces = this->transitive_interfaces();
4139     for (int j = 0; j < transitive_interfaces->length(); j++) {
4140       InstanceKlass* e = transitive_interfaces->at(j);
4141       guarantee(e->is_klass() && e->is_interface(), "invalid transitive interface");
4142     }
4143   }
4144 
4145   // Verify methods
4146   if (methods() != nullptr) {
4147     Array<Method*>* methods = this->methods();
4148     for (int j = 0; j < methods->length(); j++) {
4149       guarantee(methods->at(j)->is_method(), "non-method in methods array");
4150     }
4151     for (int j = 0; j < methods->length() - 1; j++) {
4152       Method* m1 = methods->at(j);
4153       Method* m2 = methods->at(j + 1);
4154       guarantee(m1->name()->fast_compare(m2->name()) <= 0, "methods not sorted correctly");
4155     }
4156   }
4157 
4158   // Verify method ordering
4159   if (method_ordering() != nullptr) {
4160     Array<int>* method_ordering = this->method_ordering();
4161     int length = method_ordering->length();
4162     if (JvmtiExport::can_maintain_original_method_order() ||
4163         ((CDSConfig::is_using_archive() || CDSConfig::is_dumping_archive()) && length != 0)) {
4164       guarantee(length == methods()->length(), "invalid method ordering length");
4165       jlong sum = 0;
4166       for (int j = 0; j < length; j++) {
4167         int original_index = method_ordering->at(j);
4168         guarantee(original_index >= 0, "invalid method ordering index");
4169         guarantee(original_index < length, "invalid method ordering index");
4170         sum += original_index;
4171       }
4172       // Verify sum of indices 0,1,...,length-1
4173       guarantee(sum == ((jlong)length*(length-1))/2, "invalid method ordering sum");
4174     } else {
4175       guarantee(length == 0, "invalid method ordering length");
4176     }
4177   }
4178 
4179   // Verify default methods
4180   if (default_methods() != nullptr) {
4181     Array<Method*>* methods = this->default_methods();
4182     for (int j = 0; j < methods->length(); j++) {
4183       guarantee(methods->at(j)->is_method(), "non-method in methods array");
4184     }
4185     for (int j = 0; j < methods->length() - 1; j++) {
4186       Method* m1 = methods->at(j);
4187       Method* m2 = methods->at(j + 1);
4188       guarantee(m1->name()->fast_compare(m2->name()) <= 0, "methods not sorted correctly");
4189     }
4190   }
4191 
4192   // Verify JNI static field identifiers
4193   if (jni_ids() != nullptr) {
4194     jni_ids()->verify(this);
4195   }
4196 
4197   // Verify other fields
4198   if (constants() != nullptr) {
4199     guarantee(constants()->is_constantPool(), "should be constant pool");
4200   }
4201 }
4202 
4203 void InstanceKlass::oop_verify_on(oop obj, outputStream* st) {
4204   Klass::oop_verify_on(obj, st);
4205   VerifyFieldClosure blk;
4206   obj->oop_iterate(&blk);
4207 }
4208 
4209 // JNIid class for jfieldIDs only
4210 // Note to reviewers:
4211 // These JNI functions are just moved over to column 1 and not changed
4212 // in the compressed oops workspace.
4213 JNIid::JNIid(InstanceKlass* holder, int offset, JNIid* next) {
4214   _holder = holder;
4215   _offset = offset;
4216   _next = next;
4217   DEBUG_ONLY(_is_static_field_id = false;)
4218 }
4219 
4220 JNIid* JNIid::find(int offset) {
4221   JNIid* current = this;
4222   while (current != nullptr) {
4223     if (current->offset() == offset) return current;
4224     current = current->next();
4225   }
4226   return nullptr;
4227 }
4228 
4229 void JNIid::deallocate(JNIid* current) {
4230   while (current != nullptr) {
4231     JNIid* next = current->next();
4232     delete current;
4233     current = next;
4234   }
4235 }
4236 
4237 void JNIid::verify(InstanceKlass* holder) {
4238   int first_field_offset  = InstanceMirrorKlass::offset_of_static_fields();
4239   int end_field_offset;
4240   end_field_offset = first_field_offset + (holder->static_field_size() * wordSize);
4241 
4242   JNIid* current = this;
4243   while (current != nullptr) {
4244     guarantee(current->holder() == holder, "Invalid klass in JNIid");
4245 #ifdef ASSERT
4246     int o = current->offset();
4247     if (current->is_static_field_id()) {
4248       guarantee(o >= first_field_offset  && o < end_field_offset,  "Invalid static field offset in JNIid");
4249     }
4250 #endif
4251     current = current->next();
4252   }
4253 }
4254 
4255 void InstanceKlass::set_init_state(ClassState state) {
4256 #ifdef ASSERT
4257   bool good_state = in_aot_cache() ? (_init_state <= state)
4258                                                : (_init_state < state);
4259   assert(good_state || state == allocated, "illegal state transition");
4260 #endif
4261   assert(_init_thread == nullptr, "should be cleared before state change");
4262   Atomic::release_store(&_init_state, state);
4263 }
4264 
4265 #if INCLUDE_JVMTI
4266 
4267 // RedefineClasses() support for previous versions
4268 
4269 // Globally, there is at least one previous version of a class to walk
4270 // during class unloading, which is saved because old methods in the class
4271 // are still running.   Otherwise the previous version list is cleaned up.
4272 bool InstanceKlass::_should_clean_previous_versions = false;
4273 
4274 // Returns true if there are previous versions of a class for class
4275 // unloading only. Also resets the flag to false. purge_previous_version
4276 // will set the flag to true if there are any left, i.e., if there's any
4277 // work to do for next time. This is to avoid the expensive code cache
4278 // walk in CLDG::clean_deallocate_lists().
4279 bool InstanceKlass::should_clean_previous_versions_and_reset() {
4280   bool ret = _should_clean_previous_versions;
4281   log_trace(redefine, class, iklass, purge)("Class unloading: should_clean_previous_versions = %s",
4282      ret ? "true" : "false");
4283   _should_clean_previous_versions = false;
4284   return ret;
4285 }
4286 
4287 // This nulls out the jmethodID for all obsolete methods in the previous version of the 'klass'.
4288 // These obsolete methods only exist in the previous version and we're about to delete the memory for them.
4289 // The jmethodID for these are deallocated when we unload the class, so this doesn't remove them from the table.
4290 void InstanceKlass::clear_obsolete_jmethod_ids(InstanceKlass* klass) {
4291   Array<Method*>* method_refs = klass->methods();
4292   for (int k = 0; k < method_refs->length(); k++) {
4293     Method* method = method_refs->at(k);
4294     // Only need to clear obsolete methods.
4295     if (method != nullptr && method->is_obsolete()) {
4296       method->clear_jmethod_id();
4297     }
4298   }
4299 }
4300 
4301 // Purge previous versions before adding new previous versions of the class and
4302 // during class unloading.
4303 void InstanceKlass::purge_previous_version_list() {
4304   assert(SafepointSynchronize::is_at_safepoint(), "only called at safepoint");
4305   assert(has_been_redefined(), "Should only be called for main class");
4306 
4307   // Quick exit.
4308   if (previous_versions() == nullptr) {
4309     return;
4310   }
4311 
4312   // This klass has previous versions so see what we can cleanup
4313   // while it is safe to do so.
4314 
4315   int deleted_count = 0;    // leave debugging breadcrumbs
4316   int live_count = 0;
4317   ClassLoaderData* loader_data = class_loader_data();
4318   assert(loader_data != nullptr, "should never be null");
4319 
4320   ResourceMark rm;
4321   log_trace(redefine, class, iklass, purge)("%s: previous versions", external_name());
4322 
4323   // previous versions are linked together through the InstanceKlass
4324   InstanceKlass* pv_node = previous_versions();
4325   InstanceKlass* last = this;
4326   int version = 0;
4327 
4328   // check the previous versions list
4329   for (; pv_node != nullptr; ) {
4330 
4331     ConstantPool* pvcp = pv_node->constants();
4332     assert(pvcp != nullptr, "cp ref was unexpectedly cleared");
4333 
4334     if (!pvcp->on_stack()) {
4335       // If the constant pool isn't on stack, none of the methods
4336       // are executing.  Unlink this previous_version.
4337       // The previous version InstanceKlass is on the ClassLoaderData deallocate list
4338       // so will be deallocated during the next phase of class unloading.
4339       log_trace(redefine, class, iklass, purge)
4340         ("previous version " PTR_FORMAT " is dead.", p2i(pv_node));
4341       // Unlink from previous version list.
4342       assert(pv_node->class_loader_data() == loader_data, "wrong loader_data");
4343       InstanceKlass* next = pv_node->previous_versions();
4344       clear_obsolete_jmethod_ids(pv_node); // jmethodID maintenance for the unloaded class
4345       pv_node->link_previous_versions(nullptr);   // point next to null
4346       last->link_previous_versions(next);
4347       // Delete this node directly. Nothing is referring to it and we don't
4348       // want it to increase the counter for metadata to delete in CLDG.
4349       MetadataFactory::free_metadata(loader_data, pv_node);
4350       pv_node = next;
4351       deleted_count++;
4352       version++;
4353       continue;
4354     } else {
4355       assert(pvcp->pool_holder() != nullptr, "Constant pool with no holder");
4356       guarantee (!loader_data->is_unloading(), "unloaded classes can't be on the stack");
4357       live_count++;
4358       if (pvcp->in_aot_cache()) {
4359         // Shared previous versions can never be removed so no cleaning is needed.
4360         log_trace(redefine, class, iklass, purge)("previous version " PTR_FORMAT " is shared", p2i(pv_node));
4361       } else {
4362         // Previous version alive, set that clean is needed for next time.
4363         _should_clean_previous_versions = true;
4364         log_trace(redefine, class, iklass, purge)("previous version " PTR_FORMAT " is alive", p2i(pv_node));
4365       }
4366     }
4367 
4368     // next previous version
4369     last = pv_node;
4370     pv_node = pv_node->previous_versions();
4371     version++;
4372   }
4373   log_trace(redefine, class, iklass, purge)
4374     ("previous version stats: live=%d, deleted=%d", live_count, deleted_count);
4375 }
4376 
4377 void InstanceKlass::mark_newly_obsolete_methods(Array<Method*>* old_methods,
4378                                                 int emcp_method_count) {
4379   int obsolete_method_count = old_methods->length() - emcp_method_count;
4380 
4381   if (emcp_method_count != 0 && obsolete_method_count != 0 &&
4382       _previous_versions != nullptr) {
4383     // We have a mix of obsolete and EMCP methods so we have to
4384     // clear out any matching EMCP method entries the hard way.
4385     int local_count = 0;
4386     for (int i = 0; i < old_methods->length(); i++) {
4387       Method* old_method = old_methods->at(i);
4388       if (old_method->is_obsolete()) {
4389         // only obsolete methods are interesting
4390         Symbol* m_name = old_method->name();
4391         Symbol* m_signature = old_method->signature();
4392 
4393         // previous versions are linked together through the InstanceKlass
4394         int j = 0;
4395         for (InstanceKlass* prev_version = _previous_versions;
4396              prev_version != nullptr;
4397              prev_version = prev_version->previous_versions(), j++) {
4398 
4399           Array<Method*>* method_refs = prev_version->methods();
4400           for (int k = 0; k < method_refs->length(); k++) {
4401             Method* method = method_refs->at(k);
4402 
4403             if (!method->is_obsolete() &&
4404                 method->name() == m_name &&
4405                 method->signature() == m_signature) {
4406               // The current RedefineClasses() call has made all EMCP
4407               // versions of this method obsolete so mark it as obsolete
4408               log_trace(redefine, class, iklass, add)
4409                 ("%s(%s): flush obsolete method @%d in version @%d",
4410                  m_name->as_C_string(), m_signature->as_C_string(), k, j);
4411 
4412               method->set_is_obsolete();
4413               break;
4414             }
4415           }
4416 
4417           // The previous loop may not find a matching EMCP method, but
4418           // that doesn't mean that we can optimize and not go any
4419           // further back in the PreviousVersion generations. The EMCP
4420           // method for this generation could have already been made obsolete,
4421           // but there still may be an older EMCP method that has not
4422           // been made obsolete.
4423         }
4424 
4425         if (++local_count >= obsolete_method_count) {
4426           // no more obsolete methods so bail out now
4427           break;
4428         }
4429       }
4430     }
4431   }
4432 }
4433 
4434 // Save the scratch_class as the previous version if any of the methods are running.
4435 // The previous_versions are used to set breakpoints in EMCP methods and they are
4436 // also used to clean MethodData links to redefined methods that are no longer running.
4437 void InstanceKlass::add_previous_version(InstanceKlass* scratch_class,
4438                                          int emcp_method_count) {
4439   assert(Thread::current()->is_VM_thread(),
4440          "only VMThread can add previous versions");
4441 
4442   ResourceMark rm;
4443   log_trace(redefine, class, iklass, add)
4444     ("adding previous version ref for %s, EMCP_cnt=%d", scratch_class->external_name(), emcp_method_count);
4445 
4446   // Clean out old previous versions for this class
4447   purge_previous_version_list();
4448 
4449   // Mark newly obsolete methods in remaining previous versions.  An EMCP method from
4450   // a previous redefinition may be made obsolete by this redefinition.
4451   Array<Method*>* old_methods = scratch_class->methods();
4452   mark_newly_obsolete_methods(old_methods, emcp_method_count);
4453 
4454   // If the constant pool for this previous version of the class
4455   // is not marked as being on the stack, then none of the methods
4456   // in this previous version of the class are on the stack so
4457   // we don't need to add this as a previous version.
4458   ConstantPool* cp_ref = scratch_class->constants();
4459   if (!cp_ref->on_stack()) {
4460     log_trace(redefine, class, iklass, add)("scratch class not added; no methods are running");
4461     scratch_class->class_loader_data()->add_to_deallocate_list(scratch_class);
4462     return;
4463   }
4464 
4465   // Add previous version if any methods are still running or if this is
4466   // a shared class which should never be removed.
4467   assert(scratch_class->previous_versions() == nullptr, "shouldn't have a previous version");
4468   scratch_class->link_previous_versions(previous_versions());
4469   link_previous_versions(scratch_class);
4470   if (cp_ref->in_aot_cache()) {
4471     log_trace(redefine, class, iklass, add) ("scratch class added; class is shared");
4472   } else {
4473     //  We only set clean_previous_versions flag for processing during class
4474     // unloading for non-shared classes.
4475     _should_clean_previous_versions = true;
4476     log_trace(redefine, class, iklass, add) ("scratch class added; one of its methods is on_stack.");
4477   }
4478 } // end add_previous_version()
4479 
4480 #endif // INCLUDE_JVMTI
4481 
4482 Method* InstanceKlass::method_with_idnum(int idnum) const {
4483   Method* m = nullptr;
4484   if (idnum < methods()->length()) {
4485     m = methods()->at(idnum);
4486   }
4487   if (m == nullptr || m->method_idnum() != idnum) {
4488     for (int index = 0; index < methods()->length(); ++index) {
4489       m = methods()->at(index);
4490       if (m->method_idnum() == idnum) {
4491         return m;
4492       }
4493     }
4494     // None found, return null for the caller to handle.
4495     return nullptr;
4496   }
4497   return m;
4498 }
4499 
4500 
4501 Method* InstanceKlass::method_with_orig_idnum(int idnum) const {
4502   if (idnum >= methods()->length()) {
4503     return nullptr;
4504   }
4505   Method* m = methods()->at(idnum);
4506   if (m != nullptr && m->orig_method_idnum() == idnum) {
4507     return m;
4508   }
4509   // Obsolete method idnum does not match the original idnum
4510   for (int index = 0; index < methods()->length(); ++index) {
4511     m = methods()->at(index);
4512     if (m->orig_method_idnum() == idnum) {
4513       return m;
4514     }
4515   }
4516   // None found, return null for the caller to handle.
4517   return nullptr;
4518 }
4519 
4520 
4521 Method* InstanceKlass::method_with_orig_idnum(int idnum, int version) const {
4522   const InstanceKlass* holder = get_klass_version(version);
4523   if (holder == nullptr) {
4524     return nullptr; // The version of klass is gone, no method is found
4525   }
4526   return holder->method_with_orig_idnum(idnum);
4527 }
4528 
4529 #if INCLUDE_JVMTI
4530 JvmtiCachedClassFileData* InstanceKlass::get_cached_class_file() {
4531   return _cached_class_file;
4532 }
4533 
4534 jint InstanceKlass::get_cached_class_file_len() {
4535   return VM_RedefineClasses::get_cached_class_file_len(_cached_class_file);
4536 }
4537 
4538 unsigned char * InstanceKlass::get_cached_class_file_bytes() {
4539   return VM_RedefineClasses::get_cached_class_file_bytes(_cached_class_file);
4540 }
4541 #endif
4542 
4543 // Make a step iterating over the class hierarchy under the root class.
4544 // Skips subclasses if requested.
4545 void ClassHierarchyIterator::next() {
4546   assert(_current != nullptr, "required");
4547   if (_visit_subclasses && _current->subklass() != nullptr) {
4548     _current = _current->subklass();
4549     return; // visit next subclass
4550   }
4551   _visit_subclasses = true; // reset
4552   while (_current->next_sibling() == nullptr && _current != _root) {
4553     _current = _current->java_super(); // backtrack; no more sibling subclasses left
4554   }
4555   if (_current == _root) {
4556     // Iteration is over (back at root after backtracking). Invalidate the iterator.
4557     _current = nullptr;
4558     return;
4559   }
4560   _current = _current->next_sibling();
4561   return; // visit next sibling subclass
4562 }