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