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