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/archiveUtils.hpp"
  27 #include "cds/cdsConfig.hpp"
  28 #include "cds/cdsEnumKlass.hpp"
  29 #include "cds/classListWriter.hpp"
  30 #include "cds/heapShared.hpp"
  31 #include "cds/metaspaceShared.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 "logging/log.hpp"
  54 #include "klass.inline.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/fieldStreams.inline.hpp"
  65 #include "oops/constantPool.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 "oops/inlineKlass.hpp"
  77 #include "prims/jvmtiExport.hpp"
  78 #include "prims/jvmtiRedefineClasses.hpp"
  79 #include "prims/jvmtiThreadState.hpp"
  80 #include "prims/methodComparator.hpp"
  81 #include "runtime/arguments.hpp"
  82 #include "runtime/deoptimization.hpp"
  83 #include "runtime/atomic.hpp"
  84 #include "runtime/fieldDescriptor.inline.hpp"
  85 #include "runtime/handles.inline.hpp"
  86 #include "runtime/javaCalls.hpp"
  87 #include "runtime/javaThread.inline.hpp"
  88 #include "runtime/mutexLocker.hpp"
  89 #include "runtime/orderAccess.hpp"
  90 #include "runtime/os.inline.hpp"
  91 #include "runtime/reflection.hpp"
  92 #include "runtime/synchronizer.hpp"
  93 #include "runtime/threads.hpp"
  94 #include "services/classLoadingService.hpp"
  95 #include "services/finalizerService.hpp"
  96 #include "services/threadService.hpp"
  97 #include "utilities/dtrace.hpp"
  98 #include "utilities/events.hpp"
  99 #include "utilities/macros.hpp"
 100 #include "utilities/nativeStackPrinter.hpp"
 101 #include "utilities/pair.hpp"
 102 #include "utilities/stringUtils.hpp"
 103 #ifdef COMPILER1
 104 #include "c1/c1_Compiler.hpp"
 105 #endif
 106 #if INCLUDE_JFR
 107 #include "jfr/jfrEvents.hpp"
 108 #endif
 109 
 110 #ifdef DTRACE_ENABLED
 111 
 112 
 113 #define HOTSPOT_CLASS_INITIALIZATION_required HOTSPOT_CLASS_INITIALIZATION_REQUIRED
 114 #define HOTSPOT_CLASS_INITIALIZATION_recursive HOTSPOT_CLASS_INITIALIZATION_RECURSIVE
 115 #define HOTSPOT_CLASS_INITIALIZATION_concurrent HOTSPOT_CLASS_INITIALIZATION_CONCURRENT
 116 #define HOTSPOT_CLASS_INITIALIZATION_erroneous HOTSPOT_CLASS_INITIALIZATION_ERRONEOUS
 117 #define HOTSPOT_CLASS_INITIALIZATION_super__failed HOTSPOT_CLASS_INITIALIZATION_SUPER_FAILED
 118 #define HOTSPOT_CLASS_INITIALIZATION_clinit HOTSPOT_CLASS_INITIALIZATION_CLINIT
 119 #define HOTSPOT_CLASS_INITIALIZATION_error HOTSPOT_CLASS_INITIALIZATION_ERROR
 120 #define HOTSPOT_CLASS_INITIALIZATION_end HOTSPOT_CLASS_INITIALIZATION_END
 121 #define DTRACE_CLASSINIT_PROBE(type, thread_type)                \
 122   {                                                              \
 123     char* data = nullptr;                                        \
 124     int len = 0;                                                 \
 125     Symbol* clss_name = name();                                  \
 126     if (clss_name != nullptr) {                                  \
 127       data = (char*)clss_name->bytes();                          \
 128       len = clss_name->utf8_length();                            \
 129     }                                                            \
 130     HOTSPOT_CLASS_INITIALIZATION_##type(                         \
 131       data, len, (void*)class_loader(), thread_type);            \
 132   }
 133 
 134 #define DTRACE_CLASSINIT_PROBE_WAIT(type, thread_type, wait)     \
 135   {                                                              \
 136     char* data = nullptr;                                        \
 137     int len = 0;                                                 \
 138     Symbol* clss_name = name();                                  \
 139     if (clss_name != nullptr) {                                  \
 140       data = (char*)clss_name->bytes();                          \
 141       len = clss_name->utf8_length();                            \
 142     }                                                            \
 143     HOTSPOT_CLASS_INITIALIZATION_##type(                         \
 144       data, len, (void*)class_loader(), thread_type, wait);      \
 145   }
 146 
 147 #else //  ndef DTRACE_ENABLED
 148 
 149 #define DTRACE_CLASSINIT_PROBE(type, thread_type)
 150 #define DTRACE_CLASSINIT_PROBE_WAIT(type, thread_type, wait)
 151 
 152 #endif //  ndef DTRACE_ENABLED
 153 
 154 void InlineLayoutInfo::metaspace_pointers_do(MetaspaceClosure* it) {
 155   log_trace(cds)("Iter(InlineFieldInfo): %p", this);
 156   it->push(&_klass);
 157 }
 158 
 159 bool InstanceKlass::_finalization_enabled = true;
 160 
 161 static inline bool is_class_loader(const Symbol* class_name,
 162                                    const ClassFileParser& parser) {
 163   assert(class_name != nullptr, "invariant");
 164 
 165   if (class_name == vmSymbols::java_lang_ClassLoader()) {
 166     return true;
 167   }
 168 
 169   if (vmClasses::ClassLoader_klass_loaded()) {
 170     const Klass* const super_klass = parser.super_klass();
 171     if (super_klass != nullptr) {
 172       if (super_klass->is_subtype_of(vmClasses::ClassLoader_klass())) {
 173         return true;
 174       }
 175     }
 176   }
 177   return false;
 178 }
 179 
 180 bool InstanceKlass::field_is_null_free_inline_type(int index) const {
 181   return field(index).field_flags().is_null_free_inline_type();
 182 }
 183 
 184 bool InstanceKlass::is_class_in_loadable_descriptors_attribute(Symbol* name) const {
 185   if (_loadable_descriptors == nullptr) return false;
 186   for (int i = 0; i < _loadable_descriptors->length(); i++) {
 187         Symbol* class_name = _constants->symbol_at(_loadable_descriptors->at(i));
 188         if (class_name == name) return true;
 189   }
 190   return false;
 191 }
 192 
 193 static inline bool is_stack_chunk_class(const Symbol* class_name,
 194                                         const ClassLoaderData* loader_data) {
 195   return (class_name == vmSymbols::jdk_internal_vm_StackChunk() &&
 196           loader_data->is_the_null_class_loader_data());
 197 }
 198 
 199 // private: called to verify that k is a static member of this nest.
 200 // We know that k is an instance class in the same package and hence the
 201 // same classloader.
 202 bool InstanceKlass::has_nest_member(JavaThread* current, InstanceKlass* k) const {
 203   assert(!is_hidden(), "unexpected hidden class");
 204   if (_nest_members == nullptr || _nest_members == Universe::the_empty_short_array()) {
 205     if (log_is_enabled(Trace, class, nestmates)) {
 206       ResourceMark rm(current);
 207       log_trace(class, nestmates)("Checked nest membership of %s in non-nest-host class %s",
 208                                   k->external_name(), this->external_name());
 209     }
 210     return false;
 211   }
 212 
 213   if (log_is_enabled(Trace, class, nestmates)) {
 214     ResourceMark rm(current);
 215     log_trace(class, nestmates)("Checking nest membership of %s in %s",
 216                                 k->external_name(), this->external_name());
 217   }
 218 
 219   // Check for the named class in _nest_members.
 220   // We don't resolve, or load, any classes.
 221   for (int i = 0; i < _nest_members->length(); i++) {
 222     int cp_index = _nest_members->at(i);
 223     Symbol* name = _constants->klass_name_at(cp_index);
 224     if (name == k->name()) {
 225       log_trace(class, nestmates)("- named class found at nest_members[%d] => cp[%d]", i, cp_index);
 226       return true;
 227     }
 228   }
 229   log_trace(class, nestmates)("- class is NOT a nest member!");
 230   return false;
 231 }
 232 
 233 // Called to verify that k is a permitted subclass of this class.
 234 // The incoming stringStream is used to format the messages for error logging and for the caller
 235 // to use for exception throwing.
 236 bool InstanceKlass::has_as_permitted_subclass(const InstanceKlass* k, stringStream& ss) const {
 237   Thread* current = Thread::current();
 238   assert(k != nullptr, "sanity check");
 239   assert(_permitted_subclasses != nullptr && _permitted_subclasses != Universe::the_empty_short_array(),
 240          "unexpected empty _permitted_subclasses array");
 241 
 242   if (log_is_enabled(Trace, class, sealed)) {
 243     ResourceMark rm(current);
 244     log_trace(class, sealed)("Checking for permitted subclass %s in %s",
 245                              k->external_name(), this->external_name());
 246   }
 247 
 248   // Check that the class and its super are in the same module.
 249   if (k->module() != this->module()) {
 250     ss.print("Failed same module check: subclass %s is in module '%s' with loader %s, "
 251              "and sealed class %s is in module '%s' with loader %s",
 252              k->external_name(),
 253              k->module()->name_as_C_string(),
 254              k->module()->loader_data()->loader_name_and_id(),
 255              this->external_name(),
 256              this->module()->name_as_C_string(),
 257              this->module()->loader_data()->loader_name_and_id());
 258     log_trace(class, sealed)(" - %s", ss.as_string());
 259     return false;
 260   }
 261 
 262   if (!k->is_public() && !is_same_class_package(k)) {
 263     ss.print("Failed same package check: non-public subclass %s is in package '%s' with classloader %s, "
 264              "and sealed class %s is in package '%s' with classloader %s",
 265              k->external_name(),
 266              k->package() != nullptr ? k->package()->name()->as_C_string() : "unnamed",
 267              k->module()->loader_data()->loader_name_and_id(),
 268              this->external_name(),
 269              this->package() != nullptr ? this->package()->name()->as_C_string() : "unnamed",
 270              this->module()->loader_data()->loader_name_and_id());
 271     log_trace(class, sealed)(" - %s", ss.as_string());
 272     return false;
 273   }
 274 
 275   for (int i = 0; i < _permitted_subclasses->length(); i++) {
 276     int cp_index = _permitted_subclasses->at(i);
 277     Symbol* name = _constants->klass_name_at(cp_index);
 278     if (name == k->name()) {
 279       log_trace(class, sealed)("- Found it at permitted_subclasses[%d] => cp[%d]", i, cp_index);
 280       return true;
 281     }
 282   }
 283 
 284   ss.print("Failed listed permitted subclass check: class %s is not a permitted subclass of %s",
 285            k->external_name(), this->external_name());
 286   log_trace(class, sealed)(" - %s", ss.as_string());
 287   return false;
 288 }
 289 
 290 // Return nest-host class, resolving, validating and saving it if needed.
 291 // In cases where this is called from a thread that cannot do classloading
 292 // (such as a native JIT thread) then we simply return null, which in turn
 293 // causes the access check to return false. Such code will retry the access
 294 // from a more suitable environment later. Otherwise the _nest_host is always
 295 // set once this method returns.
 296 // Any errors from nest-host resolution must be preserved so they can be queried
 297 // from higher-level access checking code, and reported as part of access checking
 298 // exceptions.
 299 // VirtualMachineErrors are propagated with a null return.
 300 // Under any conditions where the _nest_host can be set to non-null the resulting
 301 // value of it and, if applicable, the nest host resolution/validation error,
 302 // are idempotent.
 303 InstanceKlass* InstanceKlass::nest_host(TRAPS) {
 304   InstanceKlass* nest_host_k = _nest_host;
 305   if (nest_host_k != nullptr) {
 306     return nest_host_k;
 307   }
 308 
 309   ResourceMark rm(THREAD);
 310 
 311   // need to resolve and save our nest-host class.
 312   if (_nest_host_index != 0) { // we have a real nest_host
 313     // Before trying to resolve check if we're in a suitable context
 314     bool can_resolve = THREAD->can_call_java();
 315     if (!can_resolve && !_constants->tag_at(_nest_host_index).is_klass()) {
 316       log_trace(class, nestmates)("Rejected resolution of nest-host of %s in unsuitable thread",
 317                                   this->external_name());
 318       return nullptr; // sentinel to say "try again from a different context"
 319     }
 320 
 321     log_trace(class, nestmates)("Resolving nest-host of %s using cp entry for %s",
 322                                 this->external_name(),
 323                                 _constants->klass_name_at(_nest_host_index)->as_C_string());
 324 
 325     Klass* k = _constants->klass_at(_nest_host_index, THREAD);
 326     if (HAS_PENDING_EXCEPTION) {
 327       if (PENDING_EXCEPTION->is_a(vmClasses::VirtualMachineError_klass())) {
 328         return nullptr; // propagate VMEs
 329       }
 330       stringStream ss;
 331       char* target_host_class = _constants->klass_name_at(_nest_host_index)->as_C_string();
 332       ss.print("Nest host resolution of %s with host %s failed: ",
 333                this->external_name(), target_host_class);
 334       java_lang_Throwable::print(PENDING_EXCEPTION, &ss);
 335       const char* msg = ss.as_string(true /* on C-heap */);
 336       constantPoolHandle cph(THREAD, constants());
 337       SystemDictionary::add_nest_host_error(cph, _nest_host_index, msg);
 338       CLEAR_PENDING_EXCEPTION;
 339 
 340       log_trace(class, nestmates)("%s", msg);
 341     } else {
 342       // A valid nest-host is an instance class in the current package that lists this
 343       // class as a nest member. If any of these conditions are not met the class is
 344       // its own nest-host.
 345       const char* error = nullptr;
 346 
 347       // JVMS 5.4.4 indicates package check comes first
 348       if (is_same_class_package(k)) {
 349         // Now check actual membership. We can't be a member if our "host" is
 350         // not an instance class.
 351         if (k->is_instance_klass()) {
 352           nest_host_k = InstanceKlass::cast(k);
 353           bool is_member = nest_host_k->has_nest_member(THREAD, this);
 354           if (is_member) {
 355             _nest_host = nest_host_k; // save resolved nest-host value
 356 
 357             log_trace(class, nestmates)("Resolved nest-host of %s to %s",
 358                                         this->external_name(), k->external_name());
 359             return nest_host_k;
 360           } else {
 361             error = "current type is not listed as a nest member";
 362           }
 363         } else {
 364           error = "host is not an instance class";
 365         }
 366       } else {
 367         error = "types are in different packages";
 368       }
 369 
 370       // something went wrong, so record what and log it
 371       {
 372         stringStream ss;
 373         ss.print("Type %s (loader: %s) is not a nest member of type %s (loader: %s): %s",
 374                  this->external_name(),
 375                  this->class_loader_data()->loader_name_and_id(),
 376                  k->external_name(),
 377                  k->class_loader_data()->loader_name_and_id(),
 378                  error);
 379         const char* msg = ss.as_string(true /* on C-heap */);
 380         constantPoolHandle cph(THREAD, constants());
 381         SystemDictionary::add_nest_host_error(cph, _nest_host_index, msg);
 382         log_trace(class, nestmates)("%s", msg);
 383       }
 384     }
 385   } else {
 386     log_trace(class, nestmates)("Type %s is not part of a nest: setting nest-host to self",
 387                                 this->external_name());
 388   }
 389 
 390   // Either not in an explicit nest, or else an error occurred, so
 391   // the nest-host is set to `this`. Any thread that sees this assignment
 392   // will also see any setting of nest_host_error(), if applicable.
 393   return (_nest_host = this);
 394 }
 395 
 396 // Dynamic nest member support: set this class's nest host to the given class.
 397 // This occurs as part of the class definition, as soon as the instanceKlass
 398 // has been created and doesn't require further resolution. The code:
 399 //    lookup().defineHiddenClass(bytes_for_X, NESTMATE);
 400 // results in:
 401 //    class_of_X.set_nest_host(lookup().lookupClass().getNestHost())
 402 // If it has an explicit _nest_host_index or _nest_members, these will be ignored.
 403 // We also know the "host" is a valid nest-host in the same package so we can
 404 // assert some of those facts.
 405 void InstanceKlass::set_nest_host(InstanceKlass* host) {
 406   assert(is_hidden(), "must be a hidden class");
 407   assert(host != nullptr, "null nest host specified");
 408   assert(_nest_host == nullptr, "current class has resolved nest-host");
 409   assert(nest_host_error() == nullptr, "unexpected nest host resolution error exists: %s",
 410          nest_host_error());
 411   assert((host->_nest_host == nullptr && host->_nest_host_index == 0) ||
 412          (host->_nest_host == host), "proposed host is not a valid nest-host");
 413   // Can't assert this as package is not set yet:
 414   // assert(is_same_class_package(host), "proposed host is in wrong package");
 415 
 416   if (log_is_enabled(Trace, class, nestmates)) {
 417     ResourceMark rm;
 418     const char* msg = "";
 419     // a hidden class does not expect a statically defined nest-host
 420     if (_nest_host_index > 0) {
 421       msg = "(the NestHost attribute in the current class is ignored)";
 422     } else if (_nest_members != nullptr && _nest_members != Universe::the_empty_short_array()) {
 423       msg = "(the NestMembers attribute in the current class is ignored)";
 424     }
 425     log_trace(class, nestmates)("Injected type %s into the nest of %s %s",
 426                                 this->external_name(),
 427                                 host->external_name(),
 428                                 msg);
 429   }
 430   // set dynamic nest host
 431   _nest_host = host;
 432   // Record dependency to keep nest host from being unloaded before this class.
 433   ClassLoaderData* this_key = class_loader_data();
 434   assert(this_key != nullptr, "sanity");
 435   this_key->record_dependency(host);
 436 }
 437 
 438 // check if 'this' and k are nestmates (same nest_host), or k is our nest_host,
 439 // or we are k's nest_host - all of which is covered by comparing the two
 440 // resolved_nest_hosts.
 441 // Any exceptions (i.e. VMEs) are propagated.
 442 bool InstanceKlass::has_nestmate_access_to(InstanceKlass* k, TRAPS) {
 443 
 444   assert(this != k, "this should be handled by higher-level code");
 445 
 446   // Per JVMS 5.4.4 we first resolve and validate the current class, then
 447   // the target class k.
 448 
 449   InstanceKlass* cur_host = nest_host(CHECK_false);
 450   if (cur_host == nullptr) {
 451     return false;
 452   }
 453 
 454   Klass* k_nest_host = k->nest_host(CHECK_false);
 455   if (k_nest_host == nullptr) {
 456     return false;
 457   }
 458 
 459   bool access = (cur_host == k_nest_host);
 460 
 461   ResourceMark rm(THREAD);
 462   log_trace(class, nestmates)("Class %s does %shave nestmate access to %s",
 463                               this->external_name(),
 464                               access ? "" : "NOT ",
 465                               k->external_name());
 466   return access;
 467 }
 468 
 469 const char* InstanceKlass::nest_host_error() {
 470   if (_nest_host_index == 0) {
 471     return nullptr;
 472   } else {
 473     constantPoolHandle cph(Thread::current(), constants());
 474     return SystemDictionary::find_nest_host_error(cph, (int)_nest_host_index);
 475   }
 476 }
 477 
 478 void* InstanceKlass::operator new(size_t size, ClassLoaderData* loader_data, size_t word_size,
 479                                   bool use_class_space, TRAPS) throw() {
 480   return Metaspace::allocate(loader_data, word_size, ClassType, use_class_space, THREAD);
 481 }
 482 
 483 InstanceKlass* InstanceKlass::allocate_instance_klass(const ClassFileParser& parser, TRAPS) {
 484   const int size = InstanceKlass::size(parser.vtable_size(),
 485                                        parser.itable_size(),
 486                                        nonstatic_oop_map_size(parser.total_oop_map_count()),
 487                                        parser.is_interface(),
 488                                        parser.is_inline_type());
 489 
 490   const Symbol* const class_name = parser.class_name();
 491   assert(class_name != nullptr, "invariant");
 492   ClassLoaderData* loader_data = parser.loader_data();
 493   assert(loader_data != nullptr, "invariant");
 494 
 495   InstanceKlass* ik;
 496   const bool use_class_space = parser.klass_needs_narrow_id();
 497 
 498   // Allocation
 499   if (parser.is_instance_ref_klass()) {
 500     // java.lang.ref.Reference
 501     ik = new (loader_data, size, use_class_space, THREAD) InstanceRefKlass(parser);
 502   } else if (class_name == vmSymbols::java_lang_Class()) {
 503     // mirror - java.lang.Class
 504     ik = new (loader_data, size, use_class_space, THREAD) InstanceMirrorKlass(parser);
 505   } else if (is_stack_chunk_class(class_name, loader_data)) {
 506     // stack chunk
 507     ik = new (loader_data, size, use_class_space, THREAD) InstanceStackChunkKlass(parser);
 508   } else if (is_class_loader(class_name, parser)) {
 509     // class loader - java.lang.ClassLoader
 510     ik = new (loader_data, size, use_class_space, THREAD) InstanceClassLoaderKlass(parser);
 511   } else if (parser.is_inline_type()) {
 512     // inline type
 513     ik = new (loader_data, size, use_class_space, THREAD) InlineKlass(parser);
 514   } else {
 515     // normal
 516     ik = new (loader_data, size, use_class_space, THREAD) InstanceKlass(parser);
 517   }
 518 
 519   if (ik != nullptr && UseCompressedClassPointers && use_class_space) {
 520     assert(CompressedKlassPointers::is_encodable(ik),
 521            "Klass " PTR_FORMAT "needs a narrow Klass ID, but is not encodable", p2i(ik));
 522   }
 523 
 524   // Check for pending exception before adding to the loader data and incrementing
 525   // class count.  Can get OOM here.
 526   if (HAS_PENDING_EXCEPTION) {
 527     return nullptr;
 528   }
 529 
 530 #ifdef ASSERT
 531   ik->bounds_check((address) ik->start_of_vtable(), false, size);
 532   ik->bounds_check((address) ik->start_of_itable(), false, size);
 533   ik->bounds_check((address) ik->end_of_itable(), true, size);
 534   ik->bounds_check((address) ik->end_of_nonstatic_oop_maps(), true, size);
 535 #endif //ASSERT
 536   return ik;
 537 }
 538 
 539 #ifndef PRODUCT
 540 bool InstanceKlass::bounds_check(address addr, bool edge_ok, intptr_t size_in_bytes) const {
 541   const char* bad = nullptr;
 542   address end = nullptr;
 543   if (addr < (address)this) {
 544     bad = "before";
 545   } else if (addr == (address)this) {
 546     if (edge_ok)  return true;
 547     bad = "just before";
 548   } else if (addr == (end = (address)this + sizeof(intptr_t) * (size_in_bytes < 0 ? size() : size_in_bytes))) {
 549     if (edge_ok)  return true;
 550     bad = "just after";
 551   } else if (addr > end) {
 552     bad = "after";
 553   } else {
 554     return true;
 555   }
 556   tty->print_cr("%s object bounds: " INTPTR_FORMAT " [" INTPTR_FORMAT ".." INTPTR_FORMAT "]",
 557       bad, (intptr_t)addr, (intptr_t)this, (intptr_t)end);
 558   Verbose = WizardMode = true; this->print(); //@@
 559   return false;
 560 }
 561 #endif //PRODUCT
 562 
 563 // copy method ordering from resource area to Metaspace
 564 void InstanceKlass::copy_method_ordering(const intArray* m, TRAPS) {
 565   if (m != nullptr) {
 566     // allocate a new array and copy contents (memcpy?)
 567     _method_ordering = MetadataFactory::new_array<int>(class_loader_data(), m->length(), CHECK);
 568     for (int i = 0; i < m->length(); i++) {
 569       _method_ordering->at_put(i, m->at(i));
 570     }
 571   } else {
 572     _method_ordering = Universe::the_empty_int_array();
 573   }
 574 }
 575 
 576 // create a new array of vtable_indices for default methods
 577 Array<int>* InstanceKlass::create_new_default_vtable_indices(int len, TRAPS) {
 578   Array<int>* vtable_indices = MetadataFactory::new_array<int>(class_loader_data(), len, CHECK_NULL);
 579   assert(default_vtable_indices() == nullptr, "only create once");
 580   set_default_vtable_indices(vtable_indices);
 581   return vtable_indices;
 582 }
 583 
 584 
 585 InstanceKlass::InstanceKlass() {
 586   assert(CDSConfig::is_dumping_static_archive() || CDSConfig::is_using_archive(), "only for CDS");
 587 }
 588 
 589 InstanceKlass::InstanceKlass(const ClassFileParser& parser, KlassKind kind, ReferenceType reference_type) :
 590   Klass(kind),
 591   _nest_members(nullptr),
 592   _nest_host(nullptr),
 593   _permitted_subclasses(nullptr),
 594   _record_components(nullptr),
 595   _static_field_size(parser.static_field_size()),
 596   _nonstatic_oop_map_size(nonstatic_oop_map_size(parser.total_oop_map_count())),
 597   _itable_len(parser.itable_size()),
 598   _nest_host_index(0),
 599   _init_state(allocated),
 600   _reference_type(reference_type),
 601   _init_thread(nullptr),
 602   _inline_layout_info_array(nullptr),
 603   _loadable_descriptors(nullptr),
 604   _adr_inlineklass_fixed_block(nullptr)
 605 {
 606   set_vtable_length(parser.vtable_size());
 607   set_access_flags(parser.access_flags());
 608   if (parser.is_hidden()) set_is_hidden();
 609   set_layout_helper(Klass::instance_layout_helper(parser.layout_size(),
 610                                                     false));
 611   if (parser.has_inline_fields()) {
 612     set_has_inline_type_fields();
 613   }
 614 
 615   assert(nullptr == _methods, "underlying memory not zeroed?");
 616   assert(is_instance_klass(), "is layout incorrect?");
 617   assert(size_helper() == parser.layout_size(), "incorrect size_helper?");
 618 }
 619 
 620 void InstanceKlass::deallocate_methods(ClassLoaderData* loader_data,
 621                                        Array<Method*>* methods) {
 622   if (methods != nullptr && methods != Universe::the_empty_method_array() &&
 623       !methods->is_shared()) {
 624     for (int i = 0; i < methods->length(); i++) {
 625       Method* method = methods->at(i);
 626       if (method == nullptr) continue;  // maybe null if error processing
 627       // Only want to delete methods that are not executing for RedefineClasses.
 628       // The previous version will point to them so they're not totally dangling
 629       assert (!method->on_stack(), "shouldn't be called with methods on stack");
 630       MetadataFactory::free_metadata(loader_data, method);
 631     }
 632     MetadataFactory::free_array<Method*>(loader_data, methods);
 633   }
 634 }
 635 
 636 void InstanceKlass::deallocate_interfaces(ClassLoaderData* loader_data,
 637                                           const Klass* super_klass,
 638                                           Array<InstanceKlass*>* local_interfaces,
 639                                           Array<InstanceKlass*>* transitive_interfaces) {
 640   // Only deallocate transitive interfaces if not empty, same as super class
 641   // or same as local interfaces.  See code in parseClassFile.
 642   Array<InstanceKlass*>* ti = transitive_interfaces;
 643   if (ti != Universe::the_empty_instance_klass_array() && ti != local_interfaces) {
 644     // check that the interfaces don't come from super class
 645     Array<InstanceKlass*>* sti = (super_klass == nullptr) ? nullptr :
 646                     InstanceKlass::cast(super_klass)->transitive_interfaces();
 647     if (ti != sti && ti != nullptr && !ti->is_shared()) {
 648       MetadataFactory::free_array<InstanceKlass*>(loader_data, ti);
 649     }
 650   }
 651 
 652   // local interfaces can be empty
 653   if (local_interfaces != Universe::the_empty_instance_klass_array() &&
 654       local_interfaces != nullptr && !local_interfaces->is_shared()) {
 655     MetadataFactory::free_array<InstanceKlass*>(loader_data, local_interfaces);
 656   }
 657 }
 658 
 659 void InstanceKlass::deallocate_record_components(ClassLoaderData* loader_data,
 660                                                  Array<RecordComponent*>* record_components) {
 661   if (record_components != nullptr && !record_components->is_shared()) {
 662     for (int i = 0; i < record_components->length(); i++) {
 663       RecordComponent* record_component = record_components->at(i);
 664       MetadataFactory::free_metadata(loader_data, record_component);
 665     }
 666     MetadataFactory::free_array<RecordComponent*>(loader_data, record_components);
 667   }
 668 }
 669 
 670 // This function deallocates the metadata and C heap pointers that the
 671 // InstanceKlass points to.
 672 void InstanceKlass::deallocate_contents(ClassLoaderData* loader_data) {
 673   // Orphan the mirror first, CMS thinks it's still live.
 674   if (java_mirror() != nullptr) {
 675     java_lang_Class::set_klass(java_mirror(), nullptr);
 676   }
 677 
 678   // Also remove mirror from handles
 679   loader_data->remove_handle(_java_mirror);
 680 
 681   // Need to take this class off the class loader data list.
 682   loader_data->remove_class(this);
 683 
 684   // The array_klass for this class is created later, after error handling.
 685   // For class redefinition, we keep the original class so this scratch class
 686   // doesn't have an array class.  Either way, assert that there is nothing
 687   // to deallocate.
 688   assert(array_klasses() == nullptr, "array classes shouldn't be created for this class yet");
 689 
 690   // Release C heap allocated data that this points to, which includes
 691   // reference counting symbol names.
 692   // Can't release the constant pool or MethodData C heap data here because the constant
 693   // pool can be deallocated separately from the InstanceKlass for default methods and
 694   // redefine classes.  MethodData can also be released separately.
 695   release_C_heap_structures(/* release_sub_metadata */ false);
 696 
 697   deallocate_methods(loader_data, methods());
 698   set_methods(nullptr);
 699 
 700   deallocate_record_components(loader_data, record_components());
 701   set_record_components(nullptr);
 702 
 703   if (method_ordering() != nullptr &&
 704       method_ordering() != Universe::the_empty_int_array() &&
 705       !method_ordering()->is_shared()) {
 706     MetadataFactory::free_array<int>(loader_data, method_ordering());
 707   }
 708   set_method_ordering(nullptr);
 709 
 710   // default methods can be empty
 711   if (default_methods() != nullptr &&
 712       default_methods() != Universe::the_empty_method_array() &&
 713       !default_methods()->is_shared()) {
 714     MetadataFactory::free_array<Method*>(loader_data, default_methods());
 715   }
 716   // Do NOT deallocate the default methods, they are owned by superinterfaces.
 717   set_default_methods(nullptr);
 718 
 719   // default methods vtable indices can be empty
 720   if (default_vtable_indices() != nullptr &&
 721       !default_vtable_indices()->is_shared()) {
 722     MetadataFactory::free_array<int>(loader_data, default_vtable_indices());
 723   }
 724   set_default_vtable_indices(nullptr);
 725 
 726 
 727   // This array is in Klass, but remove it with the InstanceKlass since
 728   // this place would be the only caller and it can share memory with transitive
 729   // interfaces.
 730   if (secondary_supers() != nullptr &&
 731       secondary_supers() != Universe::the_empty_klass_array() &&
 732       // see comments in compute_secondary_supers about the following cast
 733       (address)(secondary_supers()) != (address)(transitive_interfaces()) &&
 734       !secondary_supers()->is_shared()) {
 735     MetadataFactory::free_array<Klass*>(loader_data, secondary_supers());
 736   }
 737   set_secondary_supers(nullptr, SECONDARY_SUPERS_BITMAP_EMPTY);
 738 
 739   deallocate_interfaces(loader_data, super(), local_interfaces(), transitive_interfaces());
 740   set_transitive_interfaces(nullptr);
 741   set_local_interfaces(nullptr);
 742 
 743   if (fieldinfo_stream() != nullptr && !fieldinfo_stream()->is_shared()) {
 744     MetadataFactory::free_array<u1>(loader_data, fieldinfo_stream());
 745   }
 746   set_fieldinfo_stream(nullptr);
 747 
 748   if (fields_status() != nullptr && !fields_status()->is_shared()) {
 749     MetadataFactory::free_array<FieldStatus>(loader_data, fields_status());
 750   }
 751   set_fields_status(nullptr);
 752 
 753   if (inline_layout_info_array() != nullptr) {
 754     MetadataFactory::free_array<InlineLayoutInfo>(loader_data, inline_layout_info_array());
 755   }
 756   set_inline_layout_info_array(nullptr);
 757 
 758   // If a method from a redefined class is using this constant pool, don't
 759   // delete it, yet.  The new class's previous version will point to this.
 760   if (constants() != nullptr) {
 761     assert (!constants()->on_stack(), "shouldn't be called if anything is onstack");
 762     if (!constants()->is_shared()) {
 763       MetadataFactory::free_metadata(loader_data, constants());
 764     }
 765     // Delete any cached resolution errors for the constant pool
 766     SystemDictionary::delete_resolution_error(constants());
 767 
 768     set_constants(nullptr);
 769   }
 770 
 771   if (inner_classes() != nullptr &&
 772       inner_classes() != Universe::the_empty_short_array() &&
 773       !inner_classes()->is_shared()) {
 774     MetadataFactory::free_array<jushort>(loader_data, inner_classes());
 775   }
 776   set_inner_classes(nullptr);
 777 
 778   if (nest_members() != nullptr &&
 779       nest_members() != Universe::the_empty_short_array() &&
 780       !nest_members()->is_shared()) {
 781     MetadataFactory::free_array<jushort>(loader_data, nest_members());
 782   }
 783   set_nest_members(nullptr);
 784 
 785   if (permitted_subclasses() != nullptr &&
 786       permitted_subclasses() != Universe::the_empty_short_array() &&
 787       !permitted_subclasses()->is_shared()) {
 788     MetadataFactory::free_array<jushort>(loader_data, permitted_subclasses());
 789   }
 790   set_permitted_subclasses(nullptr);
 791 
 792   if (loadable_descriptors() != nullptr &&
 793       loadable_descriptors() != Universe::the_empty_short_array() &&
 794       !loadable_descriptors()->is_shared()) {
 795     MetadataFactory::free_array<jushort>(loader_data, loadable_descriptors());
 796   }
 797   set_loadable_descriptors(nullptr);
 798 
 799   // We should deallocate the Annotations instance if it's not in shared spaces.
 800   if (annotations() != nullptr && !annotations()->is_shared()) {
 801     MetadataFactory::free_metadata(loader_data, annotations());
 802   }
 803   set_annotations(nullptr);
 804 
 805   SystemDictionaryShared::handle_class_unloading(this);
 806 
 807 #if INCLUDE_CDS_JAVA_HEAP
 808   if (CDSConfig::is_dumping_heap()) {
 809     HeapShared::remove_scratch_objects(this);
 810   }
 811 #endif
 812 }
 813 
 814 bool InstanceKlass::is_record() const {
 815   return _record_components != nullptr &&
 816          is_final() &&
 817          java_super() == vmClasses::Record_klass();
 818 }
 819 
 820 bool InstanceKlass::is_sealed() const {
 821   return _permitted_subclasses != nullptr &&
 822          _permitted_subclasses != Universe::the_empty_short_array();
 823 }
 824 
 825 // JLS 8.9: An enum class is either implicitly final and derives
 826 // from java.lang.Enum, or else is implicitly sealed to its
 827 // anonymous subclasses. This query detects both kinds.
 828 // It does not validate the finality or
 829 // sealing conditions: it merely checks for a super of Enum.
 830 // This is sufficient for recognizing well-formed enums.
 831 bool InstanceKlass::is_enum_subclass() const {
 832   InstanceKlass* s = java_super();
 833   return (s == vmClasses::Enum_klass() ||
 834           (s != nullptr && s->java_super() == vmClasses::Enum_klass()));
 835 }
 836 
 837 bool InstanceKlass::should_be_initialized() const {
 838   return !is_initialized();
 839 }
 840 
 841 klassItable InstanceKlass::itable() const {
 842   return klassItable(const_cast<InstanceKlass*>(this));
 843 }
 844 
 845 // JVMTI spec thinks there are signers and protection domain in the
 846 // instanceKlass.  These accessors pretend these fields are there.
 847 // The hprof specification also thinks these fields are in InstanceKlass.
 848 oop InstanceKlass::protection_domain() const {
 849   // return the protection_domain from the mirror
 850   return java_lang_Class::protection_domain(java_mirror());
 851 }
 852 
 853 objArrayOop InstanceKlass::signers() const {
 854   // return the signers from the mirror
 855   return java_lang_Class::signers(java_mirror());
 856 }
 857 
 858 oop InstanceKlass::init_lock() const {
 859   // return the init lock from the mirror
 860   oop lock = java_lang_Class::init_lock(java_mirror());
 861   // Prevent reordering with any access of initialization state
 862   OrderAccess::loadload();
 863   assert(lock != nullptr || !is_not_initialized(), // initialized or in_error state
 864          "only fully initialized state can have a null lock");
 865   return lock;
 866 }
 867 
 868 // Set the initialization lock to null so the object can be GC'ed.  Any racing
 869 // threads to get this lock will see a null lock and will not lock.
 870 // That's okay because they all check for initialized state after getting
 871 // the lock and return.
 872 void InstanceKlass::fence_and_clear_init_lock() {
 873   // make sure previous stores are all done, notably the init_state.
 874   OrderAccess::storestore();
 875   java_lang_Class::clear_init_lock(java_mirror());
 876   assert(!is_not_initialized(), "class must be initialized now");
 877 }
 878 
 879 
 880 // See "The Virtual Machine Specification" section 2.16.5 for a detailed explanation of the class initialization
 881 // process. The step comments refers to the procedure described in that section.
 882 // Note: implementation moved to static method to expose the this pointer.
 883 void InstanceKlass::initialize(TRAPS) {
 884   if (this->should_be_initialized()) {
 885     initialize_impl(CHECK);
 886     // Note: at this point the class may be initialized
 887     //       OR it may be in the state of being initialized
 888     //       in case of recursive initialization!
 889   } else {
 890     assert(is_initialized(), "sanity check");
 891   }
 892 }
 893 
 894 #ifdef ASSERT
 895 void InstanceKlass::assert_no_clinit_will_run_for_aot_initialized_class() const {
 896   assert(has_aot_initialized_mirror(), "must be");
 897 
 898   InstanceKlass* s = java_super();
 899   if (s != nullptr) {
 900     DEBUG_ONLY(ResourceMark rm);
 901     assert(s->is_initialized(), "super class %s of aot-inited class %s must have been initialized",
 902            s->external_name(), external_name());
 903     s->assert_no_clinit_will_run_for_aot_initialized_class();
 904   }
 905 
 906   Array<InstanceKlass*>* interfaces = local_interfaces();
 907   int len = interfaces->length();
 908   for (int i = 0; i < len; i++) {
 909     InstanceKlass* intf = interfaces->at(i);
 910     if (!intf->is_initialized()) {
 911       ResourceMark rm;
 912       // Note: an interface needs to be marked as is_initialized() only if
 913       // - it has a <clinit>
 914       // - it has declared a default method.
 915       assert(!intf->interface_needs_clinit_execution_as_super(/*also_check_supers*/false),
 916              "uninitialized super interface %s of aot-inited class %s must not have <clinit>",
 917              intf->external_name(), external_name());
 918     }
 919   }
 920 }
 921 #endif
 922 
 923 #if INCLUDE_CDS
 924 void InstanceKlass::initialize_with_aot_initialized_mirror(TRAPS) {
 925   assert(has_aot_initialized_mirror(), "must be");
 926   assert(CDSConfig::is_loading_heap(), "must be");
 927   assert(CDSConfig::is_using_aot_linked_classes(), "must be");
 928   assert_no_clinit_will_run_for_aot_initialized_class();
 929 
 930   if (is_initialized()) {
 931     return;
 932   }
 933 
 934   if (log_is_enabled(Info, cds, init)) {
 935     ResourceMark rm;
 936     log_info(cds, init)("%s (aot-inited)", external_name());
 937   }
 938 
 939   link_class(CHECK);
 940 
 941 #ifdef ASSERT
 942   {
 943     Handle h_init_lock(THREAD, init_lock());
 944     ObjectLocker ol(h_init_lock, THREAD);
 945     assert(!is_initialized(), "sanity");
 946     assert(!is_being_initialized(), "sanity");
 947     assert(!is_in_error_state(), "sanity");
 948   }
 949 #endif
 950 
 951   set_init_thread(THREAD);
 952   AOTClassInitializer::call_runtime_setup(THREAD, this);
 953   set_initialization_state_and_notify(fully_initialized, CHECK);
 954 }
 955 #endif
 956 
 957 bool InstanceKlass::verify_code(TRAPS) {
 958   // 1) Verify the bytecodes
 959   return Verifier::verify(this, should_verify_class(), THREAD);
 960 }
 961 
 962 void InstanceKlass::link_class(TRAPS) {
 963   assert(is_loaded(), "must be loaded");
 964   if (!is_linked()) {
 965     link_class_impl(CHECK);
 966   }
 967 }
 968 
 969 // Called to verify that a class can link during initialization, without
 970 // throwing a VerifyError.
 971 bool InstanceKlass::link_class_or_fail(TRAPS) {
 972   assert(is_loaded(), "must be loaded");
 973   if (!is_linked()) {
 974     link_class_impl(CHECK_false);
 975   }
 976   return is_linked();
 977 }
 978 
 979 bool InstanceKlass::link_class_impl(TRAPS) {
 980   if (CDSConfig::is_dumping_static_archive() && SystemDictionaryShared::has_class_failed_verification(this)) {
 981     // This is for CDS static dump only -- we use the in_error_state to indicate that
 982     // the class has failed verification. Throwing the NoClassDefFoundError here is just
 983     // a convenient way to stop repeat attempts to verify the same (bad) class.
 984     //
 985     // Note that the NoClassDefFoundError is not part of the JLS, and should not be thrown
 986     // if we are executing Java code. This is not a problem for CDS dumping phase since
 987     // it doesn't execute any Java code.
 988     ResourceMark rm(THREAD);
 989     // Names are all known to be < 64k so we know this formatted message is not excessively large.
 990     Exceptions::fthrow(THREAD_AND_LOCATION,
 991                        vmSymbols::java_lang_NoClassDefFoundError(),
 992                        "Class %s, or one of its supertypes, failed class initialization",
 993                        external_name());
 994     return false;
 995   }
 996   // return if already verified
 997   if (is_linked()) {
 998     return true;
 999   }
1000 
1001   // Timing
1002   // timer handles recursion
1003   JavaThread* jt = THREAD;
1004 
1005   // link super class before linking this class
1006   Klass* super_klass = super();
1007   if (super_klass != nullptr) {
1008     if (super_klass->is_interface()) {  // check if super class is an interface
1009       ResourceMark rm(THREAD);
1010       // Names are all known to be < 64k so we know this formatted message is not excessively large.
1011       Exceptions::fthrow(
1012         THREAD_AND_LOCATION,
1013         vmSymbols::java_lang_IncompatibleClassChangeError(),
1014         "class %s has interface %s as super class",
1015         external_name(),
1016         super_klass->external_name()
1017       );
1018       return false;
1019     }
1020 
1021     InstanceKlass* ik_super = InstanceKlass::cast(super_klass);
1022     ik_super->link_class_impl(CHECK_false);
1023   }
1024 
1025   // link all interfaces implemented by this class before linking this class
1026   Array<InstanceKlass*>* interfaces = local_interfaces();
1027   int num_interfaces = interfaces->length();
1028   for (int index = 0; index < num_interfaces; index++) {
1029     InstanceKlass* interk = interfaces->at(index);
1030     interk->link_class_impl(CHECK_false);
1031   }
1032 
1033 
1034   // If a class declares a method that uses an inline class as an argument
1035   // type or return inline type, this inline class must be loaded during the
1036   // linking of this class because size and properties of the inline class
1037   // must be known in order to be able to perform inline type optimizations.
1038   // The implementation below is an approximation of this rule, the code
1039   // iterates over all methods of the current class (including overridden
1040   // methods), not only the methods declared by this class. This
1041   // approximation makes the code simpler, and doesn't change the semantic
1042   // because classes declaring methods overridden by the current class are
1043   // linked (and have performed their own pre-loading) before the linking
1044   // of the current class.
1045 
1046 
1047   // Note:
1048   // Inline class types are loaded during
1049   // the loading phase (see ClassFileParser::post_process_parsed_stream()).
1050   // Inline class types used as element types for array creation
1051   // are not pre-loaded. Their loading is triggered by either anewarray
1052   // or multianewarray bytecodes.
1053 
1054   // Could it be possible to do the following processing only if the
1055   // class uses inline types?
1056   if (EnableValhalla) {
1057     ResourceMark rm(THREAD);
1058     for (AllFieldStream fs(this); !fs.done(); fs.next()) {
1059       if (fs.is_null_free_inline_type() && fs.access_flags().is_static()) {
1060         Symbol* sig = fs.signature();
1061         TempNewSymbol s = Signature::strip_envelope(sig);
1062         if (s != name()) {
1063           log_info(class, preload)("Preloading class %s during linking of class %s. Cause: a null-free static field is declared with this type", s->as_C_string(), name()->as_C_string());
1064           Klass* klass = SystemDictionary::resolve_or_fail(s,
1065                                                           Handle(THREAD, class_loader()), true,
1066                                                           CHECK_false);
1067           if (HAS_PENDING_EXCEPTION) {
1068             log_warning(class, preload)("Preloading of class %s during linking of class %s (cause: null-free static field) failed: %s",
1069                                       s->as_C_string(), name()->as_C_string(), PENDING_EXCEPTION->klass()->name()->as_C_string());
1070             return false; // Exception is still pending
1071           }
1072           log_info(class, preload)("Preloading of class %s during linking of class %s (cause: null-free static field) succeeded",
1073                                    s->as_C_string(), name()->as_C_string());
1074           assert(klass != nullptr, "Sanity check");
1075           if (klass->is_abstract()) {
1076             THROW_MSG_(vmSymbols::java_lang_IncompatibleClassChangeError(),
1077                       err_msg("Class %s expects class %s to be concrete value class, but it is an abstract class",
1078                       name()->as_C_string(),
1079                       InstanceKlass::cast(klass)->external_name()), false);
1080           }
1081           if (!klass->is_inline_klass()) {
1082             THROW_MSG_(vmSymbols::java_lang_IncompatibleClassChangeError(),
1083                        err_msg("class %s expects class %s to be a value class but it is an identity class",
1084                        name()->as_C_string(), klass->external_name()), false);
1085           }
1086           InlineKlass* vk = InlineKlass::cast(klass);
1087           if (!vk->is_implicitly_constructible()) {
1088              THROW_MSG_(vmSymbols::java_lang_IncompatibleClassChangeError(),
1089                         err_msg("class %s is not implicitly constructible and it is used in a null restricted static field (not supported)",
1090                         klass->external_name()), false);
1091           }
1092           // the inline_type_field_klasses_array might have been loaded with CDS, so update only if not already set and check consistency
1093           InlineLayoutInfo* li = inline_layout_info_adr(fs.index());
1094           if (li->klass() == nullptr) {
1095             li->set_klass(InlineKlass::cast(vk));
1096             li->set_kind(LayoutKind::REFERENCE);
1097           }
1098           assert(get_inline_type_field_klass(fs.index()) == vk, "Must match");
1099         } else {
1100           InlineLayoutInfo* li = inline_layout_info_adr(fs.index());
1101           if (li->klass() == nullptr) {
1102             li->set_klass(InlineKlass::cast(this));
1103             li->set_kind(LayoutKind::REFERENCE);
1104           }
1105           assert(get_inline_type_field_klass(fs.index()) == this, "Must match");
1106         }
1107       }
1108     }
1109 
1110     // Aggressively preloading all classes from the LoadableDescriptors attribute
1111     if (loadable_descriptors() != nullptr) {
1112       HandleMark hm(THREAD);
1113       for (int i = 0; i < loadable_descriptors()->length(); i++) {
1114         Symbol* sig = constants()->symbol_at(loadable_descriptors()->at(i));
1115         if (!Signature::has_envelope(sig)) continue;
1116         TempNewSymbol class_name = Signature::strip_envelope(sig);
1117         if (class_name == name()) continue;
1118         log_info(class, preload)("Preloading class %s during linking of class %s because of the class is listed in the LoadableDescriptors attribute", sig->as_C_string(), name()->as_C_string());
1119         oop loader = class_loader();
1120         Klass* klass = SystemDictionary::resolve_or_null(class_name,
1121                                                          Handle(THREAD, loader), THREAD);
1122         if (HAS_PENDING_EXCEPTION) {
1123           CLEAR_PENDING_EXCEPTION;
1124         }
1125         if (klass != nullptr) {
1126           log_info(class, preload)("Preloading of class %s during linking of class %s (cause: LoadableDescriptors attribute) succeeded", class_name->as_C_string(), name()->as_C_string());
1127           if (!klass->is_inline_klass()) {
1128             // Non value class are allowed by the current spec, but it could be an indication of an issue so let's log a warning
1129               log_warning(class, preload)("Preloading class %s during linking of class %s (cause: LoadableDescriptors attribute) but loaded class is not a value class", class_name->as_C_string(), name()->as_C_string());
1130           }
1131         } else {
1132           log_warning(class, preload)("Preloading of class %s during linking of class %s (cause: LoadableDescriptors attribute) failed", class_name->as_C_string(), name()->as_C_string());
1133         }
1134       }
1135     }
1136   }
1137 
1138   // in case the class is linked in the process of linking its superclasses
1139   if (is_linked()) {
1140     return true;
1141   }
1142 
1143   // trace only the link time for this klass that includes
1144   // the verification time
1145   PerfClassTraceTime vmtimer(ClassLoader::perf_class_link_time(),
1146                              ClassLoader::perf_class_link_selftime(),
1147                              ClassLoader::perf_classes_linked(),
1148                              jt->get_thread_stat()->perf_recursion_counts_addr(),
1149                              jt->get_thread_stat()->perf_timers_addr(),
1150                              PerfClassTraceTime::CLASS_LINK);
1151 
1152   // verification & rewriting
1153   {
1154     HandleMark hm(THREAD);
1155     Handle h_init_lock(THREAD, init_lock());
1156     ObjectLocker ol(h_init_lock, jt);
1157     // rewritten will have been set if loader constraint error found
1158     // on an earlier link attempt
1159     // don't verify or rewrite if already rewritten
1160     //
1161 
1162     if (!is_linked()) {
1163       if (!is_rewritten()) {
1164         if (is_shared()) {
1165           assert(!verified_at_dump_time(), "must be");
1166         }
1167         {
1168           bool verify_ok = verify_code(THREAD);
1169           if (!verify_ok) {
1170             return false;
1171           }
1172         }
1173 
1174         // Just in case a side-effect of verify linked this class already
1175         // (which can sometimes happen since the verifier loads classes
1176         // using custom class loaders, which are free to initialize things)
1177         if (is_linked()) {
1178           return true;
1179         }
1180 
1181         // also sets rewritten
1182         rewrite_class(CHECK_false);
1183       } else if (is_shared()) {
1184         SystemDictionaryShared::check_verification_constraints(this, CHECK_false);
1185       }
1186 
1187       // relocate jsrs and link methods after they are all rewritten
1188       link_methods(CHECK_false);
1189 
1190       // Initialize the vtable and interface table after
1191       // methods have been rewritten since rewrite may
1192       // fabricate new Method*s.
1193       // also does loader constraint checking
1194       //
1195       // initialize_vtable and initialize_itable need to be rerun
1196       // for a shared class if
1197       // 1) the class is loaded by custom class loader or
1198       // 2) the class is loaded by built-in class loader but failed to add archived loader constraints or
1199       // 3) the class was not verified during dump time
1200       bool need_init_table = true;
1201       if (is_shared() && verified_at_dump_time() &&
1202           SystemDictionaryShared::check_linking_constraints(THREAD, this)) {
1203         need_init_table = false;
1204       }
1205       if (need_init_table) {
1206         vtable().initialize_vtable_and_check_constraints(CHECK_false);
1207         itable().initialize_itable_and_check_constraints(CHECK_false);
1208       }
1209 #ifdef ASSERT
1210       vtable().verify(tty, true);
1211       // In case itable verification is ever added.
1212       // itable().verify(tty, true);
1213 #endif
1214       if (Universe::is_fully_initialized()) {
1215         DeoptimizationScope deopt_scope;
1216         {
1217           // Now mark all code that assumes the class is not linked.
1218           // Set state under the Compile_lock also.
1219           MutexLocker ml(THREAD, Compile_lock);
1220 
1221           set_init_state(linked);
1222           CodeCache::mark_dependents_on(&deopt_scope, this);
1223         }
1224         // Perform the deopt handshake outside Compile_lock.
1225         deopt_scope.deoptimize_marked();
1226       } else {
1227         set_init_state(linked);
1228       }
1229       if (JvmtiExport::should_post_class_prepare()) {
1230         JvmtiExport::post_class_prepare(THREAD, this);
1231       }
1232     }
1233   }
1234   return true;
1235 }
1236 
1237 // Rewrite the byte codes of all of the methods of a class.
1238 // The rewriter must be called exactly once. Rewriting must happen after
1239 // verification but before the first method of the class is executed.
1240 void InstanceKlass::rewrite_class(TRAPS) {
1241   assert(is_loaded(), "must be loaded");
1242   if (is_rewritten()) {
1243     assert(is_shared(), "rewriting an unshared class?");
1244     return;
1245   }
1246   Rewriter::rewrite(this, CHECK);
1247   set_rewritten();
1248 }
1249 
1250 // Now relocate and link method entry points after class is rewritten.
1251 // This is outside is_rewritten flag. In case of an exception, it can be
1252 // executed more than once.
1253 void InstanceKlass::link_methods(TRAPS) {
1254   PerfTraceTime timer(ClassLoader::perf_ik_link_methods_time());
1255 
1256   int len = methods()->length();
1257   for (int i = len-1; i >= 0; i--) {
1258     methodHandle m(THREAD, methods()->at(i));
1259 
1260     // Set up method entry points for compiler and interpreter    .
1261     m->link_method(m, CHECK);
1262   }
1263 }
1264 
1265 // Eagerly initialize superinterfaces that declare default methods (concrete instance: any access)
1266 void InstanceKlass::initialize_super_interfaces(TRAPS) {
1267   assert (has_nonstatic_concrete_methods(), "caller should have checked this");
1268   for (int i = 0; i < local_interfaces()->length(); ++i) {
1269     InstanceKlass* ik = local_interfaces()->at(i);
1270 
1271     // Initialization is depth first search ie. we start with top of the inheritance tree
1272     // has_nonstatic_concrete_methods drives searching superinterfaces since it
1273     // means has_nonstatic_concrete_methods in its superinterface hierarchy
1274     if (ik->has_nonstatic_concrete_methods()) {
1275       ik->initialize_super_interfaces(CHECK);
1276     }
1277 
1278     // Only initialize() interfaces that "declare" concrete methods.
1279     if (ik->should_be_initialized() && ik->declares_nonstatic_concrete_methods()) {
1280       ik->initialize(CHECK);
1281     }
1282   }
1283 }
1284 
1285 using InitializationErrorTable = ResourceHashtable<const InstanceKlass*, OopHandle, 107, AnyObj::C_HEAP, mtClass>;
1286 static InitializationErrorTable* _initialization_error_table;
1287 
1288 void InstanceKlass::add_initialization_error(JavaThread* current, Handle exception) {
1289   // Create the same exception with a message indicating the thread name,
1290   // and the StackTraceElements.
1291   Handle init_error = java_lang_Throwable::create_initialization_error(current, exception);
1292   ResourceMark rm(current);
1293   if (init_error.is_null()) {
1294     log_trace(class, init)("Unable to create the desired initialization error for class %s", external_name());
1295 
1296     // We failed to create the new exception, most likely due to either out-of-memory or
1297     // a stackoverflow error. If the original exception was either of those then we save
1298     // the shared, pre-allocated, stackless, instance of that exception.
1299     if (exception->klass() == vmClasses::StackOverflowError_klass()) {
1300       log_debug(class, init)("Using shared StackOverflowError as initialization error for class %s", external_name());
1301       init_error = Handle(current, Universe::class_init_stack_overflow_error());
1302     } else if (exception->klass() == vmClasses::OutOfMemoryError_klass()) {
1303       log_debug(class, init)("Using shared OutOfMemoryError as initialization error for class %s", external_name());
1304       init_error = Handle(current, Universe::class_init_out_of_memory_error());
1305     } else {
1306       return;
1307     }
1308   }
1309 
1310   MutexLocker ml(current, ClassInitError_lock);
1311   OopHandle elem = OopHandle(Universe::vm_global(), init_error());
1312   bool created;
1313   if (_initialization_error_table == nullptr) {
1314     _initialization_error_table = new (mtClass) InitializationErrorTable();
1315   }
1316   _initialization_error_table->put_if_absent(this, elem, &created);
1317   assert(created, "Initialization is single threaded");
1318   log_trace(class, init)("Initialization error added for class %s", external_name());
1319 }
1320 
1321 oop InstanceKlass::get_initialization_error(JavaThread* current) {
1322   MutexLocker ml(current, ClassInitError_lock);
1323   if (_initialization_error_table == nullptr) {
1324     return nullptr;
1325   }
1326   OopHandle* h = _initialization_error_table->get(this);
1327   return (h != nullptr) ? h->resolve() : nullptr;
1328 }
1329 
1330 // Need to remove entries for unloaded classes.
1331 void InstanceKlass::clean_initialization_error_table() {
1332   struct InitErrorTableCleaner {
1333     bool do_entry(const InstanceKlass* ik, OopHandle h) {
1334       if (!ik->is_loader_alive()) {
1335         h.release(Universe::vm_global());
1336         return true;
1337       } else {
1338         return false;
1339       }
1340     }
1341   };
1342 
1343   assert_locked_or_safepoint(ClassInitError_lock);
1344   InitErrorTableCleaner cleaner;
1345   if (_initialization_error_table != nullptr) {
1346     _initialization_error_table->unlink(&cleaner);
1347   }
1348 }
1349 
1350 void InstanceKlass::initialize_impl(TRAPS) {
1351   HandleMark hm(THREAD);
1352 
1353   // Make sure klass is linked (verified) before initialization
1354   // A class could already be verified, since it has been reflected upon.
1355   link_class(CHECK);
1356 
1357   DTRACE_CLASSINIT_PROBE(required, -1);
1358 
1359   bool wait = false;
1360 
1361   JavaThread* jt = THREAD;
1362 
1363   bool debug_logging_enabled = log_is_enabled(Debug, class, init);
1364 
1365   // refer to the JVM book page 47 for description of steps
1366   // Step 1
1367   {
1368     Handle h_init_lock(THREAD, init_lock());
1369     ObjectLocker ol(h_init_lock, jt);
1370 
1371     // Step 2
1372     // If we were to use wait() instead of waitInterruptibly() then
1373     // we might end up throwing IE from link/symbol resolution sites
1374     // that aren't expected to throw.  This would wreak havoc.  See 6320309.
1375     while (is_being_initialized() && !is_reentrant_initialization(jt)) {
1376       if (debug_logging_enabled) {
1377         ResourceMark rm(jt);
1378         log_debug(class, init)("Thread \"%s\" waiting for initialization of %s by thread \"%s\"",
1379                                jt->name(), external_name(), init_thread_name());
1380       }
1381       wait = true;
1382       jt->set_class_to_be_initialized(this);
1383       ol.wait_uninterruptibly(jt);
1384       jt->set_class_to_be_initialized(nullptr);
1385     }
1386 
1387     // Step 3
1388     if (is_being_initialized() && is_reentrant_initialization(jt)) {
1389       if (debug_logging_enabled) {
1390         ResourceMark rm(jt);
1391         log_debug(class, init)("Thread \"%s\" recursively initializing %s",
1392                                jt->name(), external_name());
1393       }
1394       DTRACE_CLASSINIT_PROBE_WAIT(recursive, -1, wait);
1395       return;
1396     }
1397 
1398     // Step 4
1399     if (is_initialized()) {
1400       if (debug_logging_enabled) {
1401         ResourceMark rm(jt);
1402         log_debug(class, init)("Thread \"%s\" found %s already initialized",
1403                                jt->name(), external_name());
1404       }
1405       DTRACE_CLASSINIT_PROBE_WAIT(concurrent, -1, wait);
1406       return;
1407     }
1408 
1409     // Step 5
1410     if (is_in_error_state()) {
1411       if (debug_logging_enabled) {
1412         ResourceMark rm(jt);
1413         log_debug(class, init)("Thread \"%s\" found %s is in error state",
1414                                jt->name(), external_name());
1415       }
1416 
1417       DTRACE_CLASSINIT_PROBE_WAIT(erroneous, -1, wait);
1418       ResourceMark rm(THREAD);
1419       Handle cause(THREAD, get_initialization_error(THREAD));
1420 
1421       stringStream ss;
1422       ss.print("Could not initialize class %s", external_name());
1423       if (cause.is_null()) {
1424         THROW_MSG(vmSymbols::java_lang_NoClassDefFoundError(), ss.as_string());
1425       } else {
1426         THROW_MSG_CAUSE(vmSymbols::java_lang_NoClassDefFoundError(),
1427                         ss.as_string(), cause);
1428       }
1429     } else {
1430 
1431       // Step 6
1432       set_init_state(being_initialized);
1433       set_init_thread(jt);
1434       if (debug_logging_enabled) {
1435         ResourceMark rm(jt);
1436         log_debug(class, init)("Thread \"%s\" is initializing %s",
1437                                jt->name(), external_name());
1438       }
1439     }
1440   }
1441 
1442   // Pre-allocating an instance of the default value
1443   if (is_inline_klass()) {
1444       InlineKlass* vk = InlineKlass::cast(this);
1445       oop val = vk->allocate_instance(THREAD);
1446       if (HAS_PENDING_EXCEPTION) {
1447           Handle e(THREAD, PENDING_EXCEPTION);
1448           CLEAR_PENDING_EXCEPTION;
1449           {
1450               EXCEPTION_MARK;
1451               add_initialization_error(THREAD, e);
1452               // Locks object, set state, and notify all waiting threads
1453               set_initialization_state_and_notify(initialization_error, THREAD);
1454               CLEAR_PENDING_EXCEPTION;
1455           }
1456           THROW_OOP(e());
1457       }
1458       vk->set_default_value(val);
1459       if (vk->has_nullable_atomic_layout()) {
1460         val = vk->allocate_instance(THREAD);
1461         if (HAS_PENDING_EXCEPTION) {
1462             Handle e(THREAD, PENDING_EXCEPTION);
1463             CLEAR_PENDING_EXCEPTION;
1464             {
1465                 EXCEPTION_MARK;
1466                 add_initialization_error(THREAD, e);
1467                 // Locks object, set state, and notify all waiting threads
1468                 set_initialization_state_and_notify(initialization_error, THREAD);
1469                 CLEAR_PENDING_EXCEPTION;
1470             }
1471             THROW_OOP(e());
1472         }
1473         vk->set_null_reset_value(val);
1474       }
1475   }
1476 
1477   // Step 7
1478   // Next, if C is a class rather than an interface, initialize it's super class and super
1479   // interfaces.
1480   if (!is_interface()) {
1481     Klass* super_klass = super();
1482     if (super_klass != nullptr && super_klass->should_be_initialized()) {
1483       super_klass->initialize(THREAD);
1484     }
1485     // If C implements any interface that declares a non-static, concrete method,
1486     // the initialization of C triggers initialization of its super interfaces.
1487     // Only need to recurse if has_nonstatic_concrete_methods which includes declaring and
1488     // having a superinterface that declares, non-static, concrete methods
1489     if (!HAS_PENDING_EXCEPTION && has_nonstatic_concrete_methods()) {
1490       initialize_super_interfaces(THREAD);
1491     }
1492 
1493     // If any exceptions, complete abruptly, throwing the same exception as above.
1494     if (HAS_PENDING_EXCEPTION) {
1495       Handle e(THREAD, PENDING_EXCEPTION);
1496       CLEAR_PENDING_EXCEPTION;
1497       {
1498         EXCEPTION_MARK;
1499         add_initialization_error(THREAD, e);
1500         // Locks object, set state, and notify all waiting threads
1501         set_initialization_state_and_notify(initialization_error, THREAD);
1502         CLEAR_PENDING_EXCEPTION;
1503       }
1504       DTRACE_CLASSINIT_PROBE_WAIT(super__failed, -1, wait);
1505       THROW_OOP(e());
1506     }
1507   }
1508 
1509   // Step 8
1510   // Initialize classes of inline fields
1511   if (EnableValhalla) {
1512     for (AllFieldStream fs(this); !fs.done(); fs.next()) {
1513       if (fs.is_null_free_inline_type()) {
1514 
1515         // inline type field klass array entries must have alreadyt been filed at load time or link time
1516         Klass* klass = get_inline_type_field_klass(fs.index());
1517 
1518         InstanceKlass::cast(klass)->initialize(THREAD);
1519         if (fs.access_flags().is_static()) {
1520           if (java_mirror()->obj_field(fs.offset()) == nullptr) {
1521             java_mirror()->obj_field_put(fs.offset(), InlineKlass::cast(klass)->default_value());
1522           }
1523         }
1524 
1525         if (HAS_PENDING_EXCEPTION) {
1526           Handle e(THREAD, PENDING_EXCEPTION);
1527           CLEAR_PENDING_EXCEPTION;
1528           {
1529             EXCEPTION_MARK;
1530             add_initialization_error(THREAD, e);
1531             // Locks object, set state, and notify all waiting threads
1532             set_initialization_state_and_notify(initialization_error, THREAD);
1533             CLEAR_PENDING_EXCEPTION;
1534           }
1535           THROW_OOP(e());
1536         }
1537       }
1538     }
1539   }
1540 
1541 
1542   // Step 9
1543   {
1544     DTRACE_CLASSINIT_PROBE_WAIT(clinit, -1, wait);
1545     if (class_initializer() != nullptr) {
1546       // Timer includes any side effects of class initialization (resolution,
1547       // etc), but not recursive entry into call_class_initializer().
1548       PerfClassTraceTime timer(ClassLoader::perf_class_init_time(),
1549                                ClassLoader::perf_class_init_selftime(),
1550                                ClassLoader::perf_classes_inited(),
1551                                jt->get_thread_stat()->perf_recursion_counts_addr(),
1552                                jt->get_thread_stat()->perf_timers_addr(),
1553                                PerfClassTraceTime::CLASS_CLINIT);
1554       call_class_initializer(THREAD);
1555     } else {
1556       // The elapsed time is so small it's not worth counting.
1557       if (UsePerfData) {
1558         ClassLoader::perf_classes_inited()->inc();
1559       }
1560       call_class_initializer(THREAD);
1561     }
1562   }
1563 
1564   // Step 10
1565   if (!HAS_PENDING_EXCEPTION) {
1566     set_initialization_state_and_notify(fully_initialized, CHECK);
1567     debug_only(vtable().verify(tty, true);)
1568   }
1569   else {
1570     // Step 11 and 12
1571     Handle e(THREAD, PENDING_EXCEPTION);
1572     CLEAR_PENDING_EXCEPTION;
1573     // JVMTI has already reported the pending exception
1574     // JVMTI internal flag reset is needed in order to report ExceptionInInitializerError
1575     JvmtiExport::clear_detected_exception(jt);
1576     {
1577       EXCEPTION_MARK;
1578       add_initialization_error(THREAD, e);
1579       set_initialization_state_and_notify(initialization_error, THREAD);
1580       CLEAR_PENDING_EXCEPTION;   // ignore any exception thrown, class initialization error is thrown below
1581       // JVMTI has already reported the pending exception
1582       // JVMTI internal flag reset is needed in order to report ExceptionInInitializerError
1583       JvmtiExport::clear_detected_exception(jt);
1584     }
1585     DTRACE_CLASSINIT_PROBE_WAIT(error, -1, wait);
1586     if (e->is_a(vmClasses::Error_klass())) {
1587       THROW_OOP(e());
1588     } else {
1589       JavaCallArguments args(e);
1590       THROW_ARG(vmSymbols::java_lang_ExceptionInInitializerError(),
1591                 vmSymbols::throwable_void_signature(),
1592                 &args);
1593     }
1594   }
1595   DTRACE_CLASSINIT_PROBE_WAIT(end, -1, wait);
1596 }
1597 
1598 
1599 void InstanceKlass::set_initialization_state_and_notify(ClassState state, TRAPS) {
1600   Handle h_init_lock(THREAD, init_lock());
1601   if (h_init_lock() != nullptr) {
1602     ObjectLocker ol(h_init_lock, THREAD);
1603     set_init_thread(nullptr); // reset _init_thread before changing _init_state
1604     set_init_state(state);
1605     fence_and_clear_init_lock();
1606     ol.notify_all(CHECK);
1607   } else {
1608     assert(h_init_lock() != nullptr, "The initialization state should never be set twice");
1609     set_init_thread(nullptr); // reset _init_thread before changing _init_state
1610     set_init_state(state);
1611   }
1612 }
1613 
1614 // Update hierarchy. This is done before the new klass has been added to the SystemDictionary. The Compile_lock
1615 // is grabbed, to ensure that the compiler is not using the class hierarchy.
1616 void InstanceKlass::add_to_hierarchy(JavaThread* current) {
1617   assert(!SafepointSynchronize::is_at_safepoint(), "must NOT be at safepoint");
1618 
1619   DeoptimizationScope deopt_scope;
1620   {
1621     MutexLocker ml(current, Compile_lock);
1622 
1623     set_init_state(InstanceKlass::loaded);
1624     // make sure init_state store is already done.
1625     // The compiler reads the hierarchy outside of the Compile_lock.
1626     // Access ordering is used to add to hierarchy.
1627 
1628     // Link into hierarchy.
1629     append_to_sibling_list();                    // add to superklass/sibling list
1630     process_interfaces();                        // handle all "implements" declarations
1631 
1632     // Now mark all code that depended on old class hierarchy.
1633     // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1634     if (Universe::is_fully_initialized()) {
1635       CodeCache::mark_dependents_on(&deopt_scope, this);
1636     }
1637   }
1638   // Perform the deopt handshake outside Compile_lock.
1639   deopt_scope.deoptimize_marked();
1640 }
1641 
1642 
1643 InstanceKlass* InstanceKlass::implementor() const {
1644   InstanceKlass* volatile* ik = adr_implementor();
1645   if (ik == nullptr) {
1646     return nullptr;
1647   } else {
1648     // This load races with inserts, and therefore needs acquire.
1649     InstanceKlass* ikls = Atomic::load_acquire(ik);
1650     if (ikls != nullptr && !ikls->is_loader_alive()) {
1651       return nullptr;  // don't return unloaded class
1652     } else {
1653       return ikls;
1654     }
1655   }
1656 }
1657 
1658 
1659 void InstanceKlass::set_implementor(InstanceKlass* ik) {
1660   assert_locked_or_safepoint(Compile_lock);
1661   assert(is_interface(), "not interface");
1662   InstanceKlass* volatile* addr = adr_implementor();
1663   assert(addr != nullptr, "null addr");
1664   if (addr != nullptr) {
1665     Atomic::release_store(addr, ik);
1666   }
1667 }
1668 
1669 int  InstanceKlass::nof_implementors() const {
1670   InstanceKlass* ik = implementor();
1671   if (ik == nullptr) {
1672     return 0;
1673   } else if (ik != this) {
1674     return 1;
1675   } else {
1676     return 2;
1677   }
1678 }
1679 
1680 // The embedded _implementor field can only record one implementor.
1681 // When there are more than one implementors, the _implementor field
1682 // is set to the interface Klass* itself. Following are the possible
1683 // values for the _implementor field:
1684 //   null                  - no implementor
1685 //   implementor Klass*    - one implementor
1686 //   self                  - more than one implementor
1687 //
1688 // The _implementor field only exists for interfaces.
1689 void InstanceKlass::add_implementor(InstanceKlass* ik) {
1690   if (Universe::is_fully_initialized()) {
1691     assert_lock_strong(Compile_lock);
1692   }
1693   assert(is_interface(), "not interface");
1694   // Filter out my subinterfaces.
1695   // (Note: Interfaces are never on the subklass list.)
1696   if (ik->is_interface()) return;
1697 
1698   // Filter out subclasses whose supers already implement me.
1699   // (Note: CHA must walk subclasses of direct implementors
1700   // in order to locate indirect implementors.)
1701   InstanceKlass* super_ik = ik->java_super();
1702   if (super_ik != nullptr && super_ik->implements_interface(this))
1703     // We only need to check one immediate superclass, since the
1704     // implements_interface query looks at transitive_interfaces.
1705     // Any supers of the super have the same (or fewer) transitive_interfaces.
1706     return;
1707 
1708   InstanceKlass* iklass = implementor();
1709   if (iklass == nullptr) {
1710     set_implementor(ik);
1711   } else if (iklass != this && iklass != ik) {
1712     // There is already an implementor. Use itself as an indicator of
1713     // more than one implementors.
1714     set_implementor(this);
1715   }
1716 
1717   // The implementor also implements the transitive_interfaces
1718   for (int index = 0; index < local_interfaces()->length(); index++) {
1719     local_interfaces()->at(index)->add_implementor(ik);
1720   }
1721 }
1722 
1723 void InstanceKlass::init_implementor() {
1724   if (is_interface()) {
1725     set_implementor(nullptr);
1726   }
1727 }
1728 
1729 
1730 void InstanceKlass::process_interfaces() {
1731   // link this class into the implementors list of every interface it implements
1732   for (int i = local_interfaces()->length() - 1; i >= 0; i--) {
1733     assert(local_interfaces()->at(i)->is_klass(), "must be a klass");
1734     InstanceKlass* interf = local_interfaces()->at(i);
1735     assert(interf->is_interface(), "expected interface");
1736     interf->add_implementor(this);
1737   }
1738 }
1739 
1740 bool InstanceKlass::can_be_primary_super_slow() const {
1741   if (is_interface())
1742     return false;
1743   else
1744     return Klass::can_be_primary_super_slow();
1745 }
1746 
1747 GrowableArray<Klass*>* InstanceKlass::compute_secondary_supers(int num_extra_slots,
1748                                                                Array<InstanceKlass*>* transitive_interfaces) {
1749   // The secondaries are the implemented interfaces.
1750   // We need the cast because Array<Klass*> is NOT a supertype of Array<InstanceKlass*>,
1751   // (but it's safe to do here because we won't write into _secondary_supers from this point on).
1752   Array<Klass*>* interfaces = (Array<Klass*>*)(address)transitive_interfaces;
1753   int num_secondaries = num_extra_slots + interfaces->length();
1754   if (num_secondaries == 0) {
1755     // Must share this for correct bootstrapping!
1756     set_secondary_supers(Universe::the_empty_klass_array(), Universe::the_empty_klass_bitmap());
1757     return nullptr;
1758   } else if (num_extra_slots == 0 && interfaces->length() <= 1) {
1759     // We will reuse the transitive interfaces list if we're certain
1760     // it's in hash order.
1761     uintx bitmap = compute_secondary_supers_bitmap(interfaces);
1762     set_secondary_supers(interfaces, bitmap);
1763     return nullptr;
1764   }
1765   // Copy transitive interfaces to a temporary growable array to be constructed
1766   // into the secondary super list with extra slots.
1767   GrowableArray<Klass*>* secondaries = new GrowableArray<Klass*>(interfaces->length());
1768   for (int i = 0; i < interfaces->length(); i++) {
1769     secondaries->push(interfaces->at(i));
1770   }
1771   return secondaries;
1772 }
1773 
1774 bool InstanceKlass::implements_interface(Klass* k) const {
1775   if (this == k) return true;
1776   assert(k->is_interface(), "should be an interface class");
1777   for (int i = 0; i < transitive_interfaces()->length(); i++) {
1778     if (transitive_interfaces()->at(i) == k) {
1779       return true;
1780     }
1781   }
1782   return false;
1783 }
1784 
1785 bool InstanceKlass::is_same_or_direct_interface(Klass *k) const {
1786   // Verify direct super interface
1787   if (this == k) return true;
1788   assert(k->is_interface(), "should be an interface class");
1789   for (int i = 0; i < local_interfaces()->length(); i++) {
1790     if (local_interfaces()->at(i) == k) {
1791       return true;
1792     }
1793   }
1794   return false;
1795 }
1796 
1797 objArrayOop InstanceKlass::allocate_objArray(int n, int length, TRAPS) {
1798   check_array_allocation_length(length, arrayOopDesc::max_array_length(T_OBJECT), CHECK_NULL);
1799   size_t size = objArrayOopDesc::object_size(length);
1800   ArrayKlass* ak = array_klass(n, CHECK_NULL);
1801   objArrayOop o = (objArrayOop)Universe::heap()->array_allocate(ak, size, length,
1802                                                                 /* do_zero */ true, CHECK_NULL);
1803   return o;
1804 }
1805 
1806 instanceOop InstanceKlass::register_finalizer(instanceOop i, TRAPS) {
1807   if (TraceFinalizerRegistration) {
1808     tty->print("Registered ");
1809     i->print_value_on(tty);
1810     tty->print_cr(" (" PTR_FORMAT ") as finalizable", p2i(i));
1811   }
1812   instanceHandle h_i(THREAD, i);
1813   // Pass the handle as argument, JavaCalls::call expects oop as jobjects
1814   JavaValue result(T_VOID);
1815   JavaCallArguments args(h_i);
1816   methodHandle mh(THREAD, Universe::finalizer_register_method());
1817   JavaCalls::call(&result, mh, &args, CHECK_NULL);
1818   MANAGEMENT_ONLY(FinalizerService::on_register(h_i(), THREAD);)
1819   return h_i();
1820 }
1821 
1822 instanceOop InstanceKlass::allocate_instance(TRAPS) {
1823   assert(!is_abstract() && !is_interface(), "Should not create this object");
1824   size_t size = size_helper();  // Query before forming handle.
1825   return (instanceOop)Universe::heap()->obj_allocate(this, size, CHECK_NULL);
1826 }
1827 
1828 instanceOop InstanceKlass::allocate_instance(oop java_class, TRAPS) {
1829   Klass* k = java_lang_Class::as_Klass(java_class);
1830   if (k == nullptr) {
1831     ResourceMark rm(THREAD);
1832     THROW_(vmSymbols::java_lang_InstantiationException(), nullptr);
1833   }
1834   InstanceKlass* ik = cast(k);
1835   ik->check_valid_for_instantiation(false, CHECK_NULL);
1836   ik->initialize(CHECK_NULL);
1837   return ik->allocate_instance(THREAD);
1838 }
1839 
1840 instanceHandle InstanceKlass::allocate_instance_handle(TRAPS) {
1841   return instanceHandle(THREAD, allocate_instance(THREAD));
1842 }
1843 
1844 void InstanceKlass::check_valid_for_instantiation(bool throwError, TRAPS) {
1845   if (is_interface() || is_abstract()) {
1846     ResourceMark rm(THREAD);
1847     THROW_MSG(throwError ? vmSymbols::java_lang_InstantiationError()
1848               : vmSymbols::java_lang_InstantiationException(), external_name());
1849   }
1850   if (this == vmClasses::Class_klass()) {
1851     ResourceMark rm(THREAD);
1852     THROW_MSG(throwError ? vmSymbols::java_lang_IllegalAccessError()
1853               : vmSymbols::java_lang_IllegalAccessException(), external_name());
1854   }
1855 }
1856 
1857 ArrayKlass* InstanceKlass::array_klass(int n, TRAPS) {
1858   // Need load-acquire for lock-free read
1859   if (array_klasses_acquire() == nullptr) {
1860 
1861     // Recursively lock array allocation
1862     RecursiveLocker rl(MultiArray_lock, THREAD);
1863 
1864     // Check if another thread created the array klass while we were waiting for the lock.
1865     if (array_klasses() == nullptr) {
1866       ObjArrayKlass* k = ObjArrayKlass::allocate_objArray_klass(class_loader_data(), 1, this, false, CHECK_NULL);
1867       // use 'release' to pair with lock-free load
1868       release_set_array_klasses(k);
1869     }
1870   }
1871 
1872   // array_klasses() will always be set at this point
1873   ArrayKlass* ak = array_klasses();
1874   assert(ak != nullptr, "should be set");
1875   return ak->array_klass(n, THREAD);
1876 }
1877 
1878 ArrayKlass* InstanceKlass::array_klass_or_null(int n) {
1879   // Need load-acquire for lock-free read
1880   ArrayKlass* ak = array_klasses_acquire();
1881   if (ak == nullptr) {
1882     return nullptr;
1883   } else {
1884     return ak->array_klass_or_null(n);
1885   }
1886 }
1887 
1888 ArrayKlass* InstanceKlass::array_klass(TRAPS) {
1889   return array_klass(1, THREAD);
1890 }
1891 
1892 ArrayKlass* InstanceKlass::array_klass_or_null() {
1893   return array_klass_or_null(1);
1894 }
1895 
1896 static int call_class_initializer_counter = 0;   // for debugging
1897 
1898 Method* InstanceKlass::class_initializer() const {
1899   Method* clinit = find_method(
1900       vmSymbols::class_initializer_name(), vmSymbols::void_method_signature());
1901   if (clinit != nullptr && clinit->is_class_initializer()) {
1902     return clinit;
1903   }
1904   return nullptr;
1905 }
1906 
1907 void InstanceKlass::call_class_initializer(TRAPS) {
1908   if (ReplayCompiles &&
1909       (ReplaySuppressInitializers == 1 ||
1910        (ReplaySuppressInitializers >= 2 && class_loader() != nullptr))) {
1911     // Hide the existence of the initializer for the purpose of replaying the compile
1912     return;
1913   }
1914 
1915 #if INCLUDE_CDS
1916   // This is needed to ensure the consistency of the archived heap objects.
1917   if (has_aot_initialized_mirror() && CDSConfig::is_loading_heap()) {
1918     AOTClassInitializer::call_runtime_setup(THREAD, this);
1919     return;
1920   } else if (has_archived_enum_objs()) {
1921     assert(is_shared(), "must be");
1922     bool initialized = CDSEnumKlass::initialize_enum_klass(this, CHECK);
1923     if (initialized) {
1924       return;
1925     }
1926   }
1927 #endif
1928 
1929   methodHandle h_method(THREAD, class_initializer());
1930   assert(!is_initialized(), "we cannot initialize twice");
1931   LogTarget(Info, class, init) lt;
1932   if (lt.is_enabled()) {
1933     ResourceMark rm(THREAD);
1934     LogStream ls(lt);
1935     ls.print("%d Initializing ", call_class_initializer_counter++);
1936     name()->print_value_on(&ls);
1937     ls.print_cr("%s (" PTR_FORMAT ") by thread \"%s\"",
1938                 h_method() == nullptr ? "(no method)" : "", p2i(this),
1939                 THREAD->name());
1940   }
1941   if (h_method() != nullptr) {
1942     ThreadInClassInitializer ticl(THREAD, this); // Track class being initialized
1943     JavaCallArguments args; // No arguments
1944     JavaValue result(T_VOID);
1945     JavaCalls::call(&result, h_method, &args, CHECK); // Static call (no args)
1946   }
1947 }
1948 
1949 // If a class that implements this interface is initialized, is the JVM required
1950 // to first execute a <clinit> method declared in this interface,
1951 // or (if also_check_supers==true) any of the super types of this interface?
1952 //
1953 // JVMS 5.5. Initialization, step 7: Next, if C is a class rather than
1954 // an interface, then let SC be its superclass and let SI1, ..., SIn
1955 // be all superinterfaces of C (whether direct or indirect) that
1956 // declare at least one non-abstract, non-static method.
1957 //
1958 // So when an interface is initialized, it does not look at its
1959 // supers. But a proper class will ensure that all of its supers have
1960 // run their <clinit> methods, except that it disregards interfaces
1961 // that lack a non-static concrete method (i.e., a default method).
1962 // Therefore, you should probably call this method only when the
1963 // current class is a super of some proper class, not an interface.
1964 bool InstanceKlass::interface_needs_clinit_execution_as_super(bool also_check_supers) const {
1965   assert(is_interface(), "must be");
1966 
1967   if (!has_nonstatic_concrete_methods()) {
1968     // quick check: no nonstatic concrete methods are declared by this or any super interfaces
1969     return false;
1970   }
1971 
1972   // JVMS 5.5. Initialization
1973   // ...If C is an interface that declares a non-abstract,
1974   // non-static method, the initialization of a class that
1975   // implements C directly or indirectly.
1976   if (declares_nonstatic_concrete_methods() && class_initializer() != nullptr) {
1977     return true;
1978   }
1979   if (also_check_supers) {
1980     Array<InstanceKlass*>* all_ifs = transitive_interfaces();
1981     for (int i = 0; i < all_ifs->length(); ++i) {
1982       InstanceKlass* super_intf = all_ifs->at(i);
1983       if (super_intf->declares_nonstatic_concrete_methods() && super_intf->class_initializer() != nullptr) {
1984         return true;
1985       }
1986     }
1987   }
1988   return false;
1989 }
1990 
1991 void InstanceKlass::mask_for(const methodHandle& method, int bci,
1992   InterpreterOopMap* entry_for) {
1993   // Lazily create the _oop_map_cache at first request.
1994   // Load_acquire is needed to safely get instance published with CAS by another thread.
1995   OopMapCache* oop_map_cache = Atomic::load_acquire(&_oop_map_cache);
1996   if (oop_map_cache == nullptr) {
1997     // Try to install new instance atomically.
1998     oop_map_cache = new OopMapCache();
1999     OopMapCache* other = Atomic::cmpxchg(&_oop_map_cache, (OopMapCache*)nullptr, oop_map_cache);
2000     if (other != nullptr) {
2001       // Someone else managed to install before us, ditch local copy and use the existing one.
2002       delete oop_map_cache;
2003       oop_map_cache = other;
2004     }
2005   }
2006   // _oop_map_cache is constant after init; lookup below does its own locking.
2007   oop_map_cache->lookup(method, bci, entry_for);
2008 }
2009 
2010 
2011 FieldInfo InstanceKlass::field(int index) const {
2012   for (AllFieldStream fs(this); !fs.done(); fs.next()) {
2013     if (fs.index() == index) {
2014       return fs.to_FieldInfo();
2015     }
2016   }
2017   fatal("Field not found");
2018   return FieldInfo();
2019 }
2020 
2021 bool InstanceKlass::find_local_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
2022   for (JavaFieldStream fs(this); !fs.done(); fs.next()) {
2023     Symbol* f_name = fs.name();
2024     Symbol* f_sig  = fs.signature();
2025     if (f_name == name && f_sig == sig) {
2026       fd->reinitialize(const_cast<InstanceKlass*>(this), fs.index());
2027       return true;
2028     }
2029   }
2030   return false;
2031 }
2032 
2033 
2034 Klass* InstanceKlass::find_interface_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
2035   const int n = local_interfaces()->length();
2036   for (int i = 0; i < n; i++) {
2037     Klass* intf1 = local_interfaces()->at(i);
2038     assert(intf1->is_interface(), "just checking type");
2039     // search for field in current interface
2040     if (InstanceKlass::cast(intf1)->find_local_field(name, sig, fd)) {
2041       assert(fd->is_static(), "interface field must be static");
2042       return intf1;
2043     }
2044     // search for field in direct superinterfaces
2045     Klass* intf2 = InstanceKlass::cast(intf1)->find_interface_field(name, sig, fd);
2046     if (intf2 != nullptr) return intf2;
2047   }
2048   // otherwise field lookup fails
2049   return nullptr;
2050 }
2051 
2052 
2053 Klass* InstanceKlass::find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
2054   // search order according to newest JVM spec (5.4.3.2, p.167).
2055   // 1) search for field in current klass
2056   if (find_local_field(name, sig, fd)) {
2057     return const_cast<InstanceKlass*>(this);
2058   }
2059   // 2) search for field recursively in direct superinterfaces
2060   { Klass* intf = find_interface_field(name, sig, fd);
2061     if (intf != nullptr) return intf;
2062   }
2063   // 3) apply field lookup recursively if superclass exists
2064   { Klass* supr = super();
2065     if (supr != nullptr) return InstanceKlass::cast(supr)->find_field(name, sig, fd);
2066   }
2067   // 4) otherwise field lookup fails
2068   return nullptr;
2069 }
2070 
2071 
2072 Klass* InstanceKlass::find_field(Symbol* name, Symbol* sig, bool is_static, fieldDescriptor* fd) const {
2073   // search order according to newest JVM spec (5.4.3.2, p.167).
2074   // 1) search for field in current klass
2075   if (find_local_field(name, sig, fd)) {
2076     if (fd->is_static() == is_static) return const_cast<InstanceKlass*>(this);
2077   }
2078   // 2) search for field recursively in direct superinterfaces
2079   if (is_static) {
2080     Klass* intf = find_interface_field(name, sig, fd);
2081     if (intf != nullptr) return intf;
2082   }
2083   // 3) apply field lookup recursively if superclass exists
2084   { Klass* supr = super();
2085     if (supr != nullptr) return InstanceKlass::cast(supr)->find_field(name, sig, is_static, fd);
2086   }
2087   // 4) otherwise field lookup fails
2088   return nullptr;
2089 }
2090 
2091 bool InstanceKlass::contains_field_offset(int offset) {
2092   if (this->is_inline_klass()) {
2093     InlineKlass* vk = InlineKlass::cast(this);
2094     return offset >= vk->payload_offset() && offset < (vk->payload_offset() + vk->payload_size_in_bytes());
2095   } else {
2096     fieldDescriptor fd;
2097     return find_field_from_offset(offset, false, &fd);
2098   }
2099 }
2100 
2101 bool InstanceKlass::find_local_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const {
2102   for (JavaFieldStream fs(this); !fs.done(); fs.next()) {
2103     if (fs.offset() == offset) {
2104       fd->reinitialize(const_cast<InstanceKlass*>(this), fs.index());
2105       if (fd->is_static() == is_static) return true;
2106     }
2107   }
2108   return false;
2109 }
2110 
2111 
2112 bool InstanceKlass::find_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const {
2113   Klass* klass = const_cast<InstanceKlass*>(this);
2114   while (klass != nullptr) {
2115     if (InstanceKlass::cast(klass)->find_local_field_from_offset(offset, is_static, fd)) {
2116       return true;
2117     }
2118     klass = klass->super();
2119   }
2120   return false;
2121 }
2122 
2123 
2124 void InstanceKlass::methods_do(void f(Method* method)) {
2125   // Methods aren't stable until they are loaded.  This can be read outside
2126   // a lock through the ClassLoaderData for profiling
2127   // Redefined scratch classes are on the list and need to be cleaned
2128   if (!is_loaded() && !is_scratch_class()) {
2129     return;
2130   }
2131 
2132   int len = methods()->length();
2133   for (int index = 0; index < len; index++) {
2134     Method* m = methods()->at(index);
2135     assert(m->is_method(), "must be method");
2136     f(m);
2137   }
2138 }
2139 
2140 
2141 void InstanceKlass::do_local_static_fields(FieldClosure* cl) {
2142   for (JavaFieldStream fs(this); !fs.done(); fs.next()) {
2143     if (fs.access_flags().is_static()) {
2144       fieldDescriptor& fd = fs.field_descriptor();
2145       cl->do_field(&fd);
2146     }
2147   }
2148 }
2149 
2150 
2151 void InstanceKlass::do_local_static_fields(void f(fieldDescriptor*, Handle, TRAPS), Handle mirror, TRAPS) {
2152   for (JavaFieldStream fs(this); !fs.done(); fs.next()) {
2153     if (fs.access_flags().is_static()) {
2154       fieldDescriptor& fd = fs.field_descriptor();
2155       f(&fd, mirror, CHECK);
2156     }
2157   }
2158 }
2159 
2160 void InstanceKlass::do_nonstatic_fields(FieldClosure* cl) {
2161   InstanceKlass* super = superklass();
2162   if (super != nullptr) {
2163     super->do_nonstatic_fields(cl);
2164   }
2165   fieldDescriptor fd;
2166   int length = java_fields_count();
2167   for (int i = 0; i < length; i += 1) {
2168     fd.reinitialize(this, i);
2169     if (!fd.is_static()) {
2170       cl->do_field(&fd);
2171     }
2172   }
2173 }
2174 
2175 // first in Pair is offset, second is index.
2176 static int compare_fields_by_offset(Pair<int,int>* a, Pair<int,int>* b) {
2177   return a->first - b->first;
2178 }
2179 
2180 void InstanceKlass::print_nonstatic_fields(FieldClosure* cl) {
2181   InstanceKlass* super = superklass();
2182   if (super != nullptr) {
2183     super->print_nonstatic_fields(cl);
2184   }
2185   ResourceMark rm;
2186   fieldDescriptor fd;
2187   // In DebugInfo nonstatic fields are sorted by offset.
2188   GrowableArray<Pair<int,int> > fields_sorted;
2189   int i = 0;
2190   for (AllFieldStream fs(this); !fs.done(); fs.next()) {
2191     if (!fs.access_flags().is_static()) {
2192       fd = fs.field_descriptor();
2193       Pair<int,int> f(fs.offset(), fs.index());
2194       fields_sorted.push(f);
2195       i++;
2196     }
2197   }
2198   if (i > 0) {
2199     int length = i;
2200     assert(length == fields_sorted.length(), "duh");
2201     fields_sorted.sort(compare_fields_by_offset);
2202     for (int i = 0; i < length; i++) {
2203       fd.reinitialize(this, fields_sorted.at(i).second);
2204       assert(!fd.is_static() && fd.offset() == fields_sorted.at(i).first, "only nonstatic fields");
2205       cl->do_field(&fd);
2206     }
2207   }
2208 }
2209 
2210 #ifdef ASSERT
2211 static int linear_search(const Array<Method*>* methods,
2212                          const Symbol* name,
2213                          const Symbol* signature) {
2214   const int len = methods->length();
2215   for (int index = 0; index < len; index++) {
2216     const Method* const m = methods->at(index);
2217     assert(m->is_method(), "must be method");
2218     if (m->signature() == signature && m->name() == name) {
2219        return index;
2220     }
2221   }
2222   return -1;
2223 }
2224 #endif
2225 
2226 bool InstanceKlass::_disable_method_binary_search = false;
2227 
2228 NOINLINE int linear_search(const Array<Method*>* methods, const Symbol* name) {
2229   int len = methods->length();
2230   int l = 0;
2231   int h = len - 1;
2232   while (l <= h) {
2233     Method* m = methods->at(l);
2234     if (m->name() == name) {
2235       return l;
2236     }
2237     l++;
2238   }
2239   return -1;
2240 }
2241 
2242 inline int InstanceKlass::quick_search(const Array<Method*>* methods, const Symbol* name) {
2243   if (_disable_method_binary_search) {
2244     assert(CDSConfig::is_dumping_dynamic_archive(), "must be");
2245     // At the final stage of dynamic dumping, the methods array may not be sorted
2246     // by ascending addresses of their names, so we can't use binary search anymore.
2247     // However, methods with the same name are still laid out consecutively inside the
2248     // methods array, so let's look for the first one that matches.
2249     return linear_search(methods, name);
2250   }
2251 
2252   int len = methods->length();
2253   int l = 0;
2254   int h = len - 1;
2255 
2256   // methods are sorted by ascending addresses of their names, so do binary search
2257   while (l <= h) {
2258     int mid = (l + h) >> 1;
2259     Method* m = methods->at(mid);
2260     assert(m->is_method(), "must be method");
2261     int res = m->name()->fast_compare(name);
2262     if (res == 0) {
2263       return mid;
2264     } else if (res < 0) {
2265       l = mid + 1;
2266     } else {
2267       h = mid - 1;
2268     }
2269   }
2270   return -1;
2271 }
2272 
2273 // find_method looks up the name/signature in the local methods array
2274 Method* InstanceKlass::find_method(const Symbol* name,
2275                                    const Symbol* signature) const {
2276   return find_method_impl(name, signature,
2277                           OverpassLookupMode::find,
2278                           StaticLookupMode::find,
2279                           PrivateLookupMode::find);
2280 }
2281 
2282 Method* InstanceKlass::find_method_impl(const Symbol* name,
2283                                         const Symbol* signature,
2284                                         OverpassLookupMode overpass_mode,
2285                                         StaticLookupMode static_mode,
2286                                         PrivateLookupMode private_mode) const {
2287   return InstanceKlass::find_method_impl(methods(),
2288                                          name,
2289                                          signature,
2290                                          overpass_mode,
2291                                          static_mode,
2292                                          private_mode);
2293 }
2294 
2295 // find_instance_method looks up the name/signature in the local methods array
2296 // and skips over static methods
2297 Method* InstanceKlass::find_instance_method(const Array<Method*>* methods,
2298                                             const Symbol* name,
2299                                             const Symbol* signature,
2300                                             PrivateLookupMode private_mode) {
2301   Method* const meth = InstanceKlass::find_method_impl(methods,
2302                                                  name,
2303                                                  signature,
2304                                                  OverpassLookupMode::find,
2305                                                  StaticLookupMode::skip,
2306                                                  private_mode);
2307   assert(((meth == nullptr) || !meth->is_static()),
2308     "find_instance_method should have skipped statics");
2309   return meth;
2310 }
2311 
2312 // find_instance_method looks up the name/signature in the local methods array
2313 // and skips over static methods
2314 Method* InstanceKlass::find_instance_method(const Symbol* name,
2315                                             const Symbol* signature,
2316                                             PrivateLookupMode private_mode) const {
2317   return InstanceKlass::find_instance_method(methods(), name, signature, private_mode);
2318 }
2319 
2320 // Find looks up the name/signature in the local methods array
2321 // and filters on the overpass, static and private flags
2322 // This returns the first one found
2323 // note that the local methods array can have up to one overpass, one static
2324 // and one instance (private or not) with the same name/signature
2325 Method* InstanceKlass::find_local_method(const Symbol* name,
2326                                          const Symbol* signature,
2327                                          OverpassLookupMode overpass_mode,
2328                                          StaticLookupMode static_mode,
2329                                          PrivateLookupMode private_mode) const {
2330   return InstanceKlass::find_method_impl(methods(),
2331                                          name,
2332                                          signature,
2333                                          overpass_mode,
2334                                          static_mode,
2335                                          private_mode);
2336 }
2337 
2338 // Find looks up the name/signature in the local methods array
2339 // and filters on the overpass, static and private flags
2340 // This returns the first one found
2341 // note that the local methods array can have up to one overpass, one static
2342 // and one instance (private or not) with the same name/signature
2343 Method* InstanceKlass::find_local_method(const Array<Method*>* methods,
2344                                          const Symbol* name,
2345                                          const Symbol* signature,
2346                                          OverpassLookupMode overpass_mode,
2347                                          StaticLookupMode static_mode,
2348                                          PrivateLookupMode private_mode) {
2349   return InstanceKlass::find_method_impl(methods,
2350                                          name,
2351                                          signature,
2352                                          overpass_mode,
2353                                          static_mode,
2354                                          private_mode);
2355 }
2356 
2357 Method* InstanceKlass::find_method(const Array<Method*>* methods,
2358                                    const Symbol* name,
2359                                    const Symbol* signature) {
2360   return InstanceKlass::find_method_impl(methods,
2361                                          name,
2362                                          signature,
2363                                          OverpassLookupMode::find,
2364                                          StaticLookupMode::find,
2365                                          PrivateLookupMode::find);
2366 }
2367 
2368 Method* InstanceKlass::find_method_impl(const Array<Method*>* methods,
2369                                         const Symbol* name,
2370                                         const Symbol* signature,
2371                                         OverpassLookupMode overpass_mode,
2372                                         StaticLookupMode static_mode,
2373                                         PrivateLookupMode private_mode) {
2374   int hit = find_method_index(methods, name, signature, overpass_mode, static_mode, private_mode);
2375   return hit >= 0 ? methods->at(hit): nullptr;
2376 }
2377 
2378 // true if method matches signature and conforms to skipping_X conditions.
2379 static bool method_matches(const Method* m,
2380                            const Symbol* signature,
2381                            bool skipping_overpass,
2382                            bool skipping_static,
2383                            bool skipping_private) {
2384   return ((m->signature() == signature) &&
2385     (!skipping_overpass || !m->is_overpass()) &&
2386     (!skipping_static || !m->is_static()) &&
2387     (!skipping_private || !m->is_private()));
2388 }
2389 
2390 // Used directly for default_methods to find the index into the
2391 // default_vtable_indices, and indirectly by find_method
2392 // find_method_index looks in the local methods array to return the index
2393 // of the matching name/signature. If, overpass methods are being ignored,
2394 // the search continues to find a potential non-overpass match.  This capability
2395 // is important during method resolution to prefer a static method, for example,
2396 // over an overpass method.
2397 // There is the possibility in any _method's array to have the same name/signature
2398 // for a static method, an overpass method and a local instance method
2399 // To correctly catch a given method, the search criteria may need
2400 // to explicitly skip the other two. For local instance methods, it
2401 // is often necessary to skip private methods
2402 int InstanceKlass::find_method_index(const Array<Method*>* methods,
2403                                      const Symbol* name,
2404                                      const Symbol* signature,
2405                                      OverpassLookupMode overpass_mode,
2406                                      StaticLookupMode static_mode,
2407                                      PrivateLookupMode private_mode) {
2408   const bool skipping_overpass = (overpass_mode == OverpassLookupMode::skip);
2409   const bool skipping_static = (static_mode == StaticLookupMode::skip);
2410   const bool skipping_private = (private_mode == PrivateLookupMode::skip);
2411   const int hit = quick_search(methods, name);
2412   if (hit != -1) {
2413     const Method* const m = methods->at(hit);
2414 
2415     // Do linear search to find matching signature.  First, quick check
2416     // for common case, ignoring overpasses if requested.
2417     if (method_matches(m, signature, skipping_overpass, skipping_static, skipping_private)) {
2418       return hit;
2419     }
2420 
2421     // search downwards through overloaded methods
2422     int i;
2423     for (i = hit - 1; i >= 0; --i) {
2424         const Method* const m = methods->at(i);
2425         assert(m->is_method(), "must be method");
2426         if (m->name() != name) {
2427           break;
2428         }
2429         if (method_matches(m, signature, skipping_overpass, skipping_static, skipping_private)) {
2430           return i;
2431         }
2432     }
2433     // search upwards
2434     for (i = hit + 1; i < methods->length(); ++i) {
2435         const Method* const m = methods->at(i);
2436         assert(m->is_method(), "must be method");
2437         if (m->name() != name) {
2438           break;
2439         }
2440         if (method_matches(m, signature, skipping_overpass, skipping_static, skipping_private)) {
2441           return i;
2442         }
2443     }
2444     // not found
2445 #ifdef ASSERT
2446     const int index = (skipping_overpass || skipping_static || skipping_private) ? -1 :
2447       linear_search(methods, name, signature);
2448     assert(-1 == index, "binary search should have found entry %d", index);
2449 #endif
2450   }
2451   return -1;
2452 }
2453 
2454 int InstanceKlass::find_method_by_name(const Symbol* name, int* end) const {
2455   return find_method_by_name(methods(), name, end);
2456 }
2457 
2458 int InstanceKlass::find_method_by_name(const Array<Method*>* methods,
2459                                        const Symbol* name,
2460                                        int* end_ptr) {
2461   assert(end_ptr != nullptr, "just checking");
2462   int start = quick_search(methods, name);
2463   int end = start + 1;
2464   if (start != -1) {
2465     while (start - 1 >= 0 && (methods->at(start - 1))->name() == name) --start;
2466     while (end < methods->length() && (methods->at(end))->name() == name) ++end;
2467     *end_ptr = end;
2468     return start;
2469   }
2470   return -1;
2471 }
2472 
2473 // uncached_lookup_method searches both the local class methods array and all
2474 // superclasses methods arrays, skipping any overpass methods in superclasses,
2475 // and possibly skipping private methods.
2476 Method* InstanceKlass::uncached_lookup_method(const Symbol* name,
2477                                               const Symbol* signature,
2478                                               OverpassLookupMode overpass_mode,
2479                                               PrivateLookupMode private_mode) const {
2480   OverpassLookupMode overpass_local_mode = overpass_mode;
2481   const Klass* klass = this;
2482   while (klass != nullptr) {
2483     Method* const method = InstanceKlass::cast(klass)->find_method_impl(name,
2484                                                                         signature,
2485                                                                         overpass_local_mode,
2486                                                                         StaticLookupMode::find,
2487                                                                         private_mode);
2488     if (method != nullptr) {
2489       return method;
2490     }
2491     if (name == vmSymbols::object_initializer_name()) {
2492       break;  // <init> is never inherited
2493     }
2494     klass = klass->super();
2495     overpass_local_mode = OverpassLookupMode::skip;   // Always ignore overpass methods in superclasses
2496   }
2497   return nullptr;
2498 }
2499 
2500 #ifdef ASSERT
2501 // search through class hierarchy and return true if this class or
2502 // one of the superclasses was redefined
2503 bool InstanceKlass::has_redefined_this_or_super() const {
2504   const Klass* klass = this;
2505   while (klass != nullptr) {
2506     if (InstanceKlass::cast(klass)->has_been_redefined()) {
2507       return true;
2508     }
2509     klass = klass->super();
2510   }
2511   return false;
2512 }
2513 #endif
2514 
2515 // lookup a method in the default methods list then in all transitive interfaces
2516 // Do NOT return private or static methods
2517 Method* InstanceKlass::lookup_method_in_ordered_interfaces(Symbol* name,
2518                                                          Symbol* signature) const {
2519   Method* m = nullptr;
2520   if (default_methods() != nullptr) {
2521     m = find_method(default_methods(), name, signature);
2522   }
2523   // Look up interfaces
2524   if (m == nullptr) {
2525     m = lookup_method_in_all_interfaces(name, signature, DefaultsLookupMode::find);
2526   }
2527   return m;
2528 }
2529 
2530 // lookup a method in all the interfaces that this class implements
2531 // Do NOT return private or static methods, new in JDK8 which are not externally visible
2532 // They should only be found in the initial InterfaceMethodRef
2533 Method* InstanceKlass::lookup_method_in_all_interfaces(Symbol* name,
2534                                                        Symbol* signature,
2535                                                        DefaultsLookupMode defaults_mode) const {
2536   Array<InstanceKlass*>* all_ifs = transitive_interfaces();
2537   int num_ifs = all_ifs->length();
2538   InstanceKlass *ik = nullptr;
2539   for (int i = 0; i < num_ifs; i++) {
2540     ik = all_ifs->at(i);
2541     Method* m = ik->lookup_method(name, signature);
2542     if (m != nullptr && m->is_public() && !m->is_static() &&
2543         ((defaults_mode != DefaultsLookupMode::skip) || !m->is_default_method())) {
2544       return m;
2545     }
2546   }
2547   return nullptr;
2548 }
2549 
2550 PrintClassClosure::PrintClassClosure(outputStream* st, bool verbose)
2551   :_st(st), _verbose(verbose) {
2552   ResourceMark rm;
2553   _st->print("%-18s  ", "KlassAddr");
2554   _st->print("%-4s  ", "Size");
2555   _st->print("%-20s  ", "State");
2556   _st->print("%-7s  ", "Flags");
2557   _st->print("%-5s  ", "ClassName");
2558   _st->cr();
2559 }
2560 
2561 void PrintClassClosure::do_klass(Klass* k)  {
2562   ResourceMark rm;
2563   // klass pointer
2564   _st->print(PTR_FORMAT "  ", p2i(k));
2565   // klass size
2566   _st->print("%4d  ", k->size());
2567   // initialization state
2568   if (k->is_instance_klass()) {
2569     _st->print("%-20s  ",InstanceKlass::cast(k)->init_state_name());
2570   } else {
2571     _st->print("%-20s  ","");
2572   }
2573   // misc flags(Changes should synced with ClassesDCmd::ClassesDCmd help doc)
2574   char buf[10];
2575   int i = 0;
2576   if (k->has_finalizer()) buf[i++] = 'F';
2577   if (k->is_instance_klass()) {
2578     InstanceKlass* ik = InstanceKlass::cast(k);
2579     if (ik->has_final_method()) buf[i++] = 'f';
2580     if (ik->is_rewritten()) buf[i++] = 'W';
2581     if (ik->is_contended()) buf[i++] = 'C';
2582     if (ik->has_been_redefined()) buf[i++] = 'R';
2583     if (ik->is_shared()) buf[i++] = 'S';
2584   }
2585   buf[i++] = '\0';
2586   _st->print("%-7s  ", buf);
2587   // klass name
2588   _st->print("%-5s  ", k->external_name());
2589   // end
2590   _st->cr();
2591   if (_verbose) {
2592     k->print_on(_st);
2593   }
2594 }
2595 
2596 /* jni_id_for for jfieldIds only */
2597 JNIid* InstanceKlass::jni_id_for(int offset) {
2598   MutexLocker ml(JfieldIdCreation_lock);
2599   JNIid* probe = jni_ids() == nullptr ? nullptr : jni_ids()->find(offset);
2600   if (probe == nullptr) {
2601     // Allocate new static field identifier
2602     probe = new JNIid(this, offset, jni_ids());
2603     set_jni_ids(probe);
2604   }
2605   return probe;
2606 }
2607 
2608 u2 InstanceKlass::enclosing_method_data(int offset) const {
2609   const Array<jushort>* const inner_class_list = inner_classes();
2610   if (inner_class_list == nullptr) {
2611     return 0;
2612   }
2613   const int length = inner_class_list->length();
2614   if (length % inner_class_next_offset == 0) {
2615     return 0;
2616   }
2617   const int index = length - enclosing_method_attribute_size;
2618   assert(offset < enclosing_method_attribute_size, "invalid offset");
2619   return inner_class_list->at(index + offset);
2620 }
2621 
2622 void InstanceKlass::set_enclosing_method_indices(u2 class_index,
2623                                                  u2 method_index) {
2624   Array<jushort>* inner_class_list = inner_classes();
2625   assert (inner_class_list != nullptr, "_inner_classes list is not set up");
2626   int length = inner_class_list->length();
2627   if (length % inner_class_next_offset == enclosing_method_attribute_size) {
2628     int index = length - enclosing_method_attribute_size;
2629     inner_class_list->at_put(
2630       index + enclosing_method_class_index_offset, class_index);
2631     inner_class_list->at_put(
2632       index + enclosing_method_method_index_offset, method_index);
2633   }
2634 }
2635 
2636 jmethodID InstanceKlass::update_jmethod_id(jmethodID* jmeths, Method* method, int idnum) {
2637   if (method->is_old() && !method->is_obsolete()) {
2638     // If the method passed in is old (but not obsolete), use the current version.
2639     method = method_with_idnum((int)idnum);
2640     assert(method != nullptr, "old and but not obsolete, so should exist");
2641   }
2642   jmethodID new_id = Method::make_jmethod_id(class_loader_data(), method);
2643   Atomic::release_store(&jmeths[idnum + 1], new_id);
2644   return new_id;
2645 }
2646 
2647 // Lookup or create a jmethodID.
2648 // This code is called by the VMThread and JavaThreads so the
2649 // locking has to be done very carefully to avoid deadlocks
2650 // and/or other cache consistency problems.
2651 //
2652 jmethodID InstanceKlass::get_jmethod_id(const methodHandle& method_h) {
2653   Method* method = method_h();
2654   int idnum = method->method_idnum();
2655   jmethodID* jmeths = methods_jmethod_ids_acquire();
2656 
2657   // We use a double-check locking idiom here because this cache is
2658   // performance sensitive. In the normal system, this cache only
2659   // transitions from null to non-null which is safe because we use
2660   // release_set_methods_jmethod_ids() to advertise the new cache.
2661   // A partially constructed cache should never be seen by a racing
2662   // thread. We also use release_store() to save a new jmethodID
2663   // in the cache so a partially constructed jmethodID should never be
2664   // seen either. Cache reads of existing jmethodIDs proceed without a
2665   // lock, but cache writes of a new jmethodID requires uniqueness and
2666   // creation of the cache itself requires no leaks so a lock is
2667   // acquired in those two cases.
2668   //
2669   // If the RedefineClasses() API has been used, then this cache grows
2670   // in the redefinition safepoint.
2671 
2672   if (jmeths == nullptr) {
2673     MutexLocker ml(JmethodIdCreation_lock, Mutex::_no_safepoint_check_flag);
2674     jmeths = methods_jmethod_ids_acquire();
2675     // Still null?
2676     if (jmeths == nullptr) {
2677       size_t size = idnum_allocated_count();
2678       assert(size > (size_t)idnum, "should already have space");
2679       jmeths = NEW_C_HEAP_ARRAY(jmethodID, size + 1, mtClass);
2680       memset(jmeths, 0, (size + 1) * sizeof(jmethodID));
2681       // cache size is stored in element[0], other elements offset by one
2682       jmeths[0] = (jmethodID)size;
2683       jmethodID new_id = update_jmethod_id(jmeths, method, idnum);
2684 
2685       // publish jmeths
2686       release_set_methods_jmethod_ids(jmeths);
2687       return new_id;
2688     }
2689   }
2690 
2691   jmethodID id = Atomic::load_acquire(&jmeths[idnum + 1]);
2692   if (id == nullptr) {
2693     MutexLocker ml(JmethodIdCreation_lock, Mutex::_no_safepoint_check_flag);
2694     id = jmeths[idnum + 1];
2695     // Still null?
2696     if (id == nullptr) {
2697       return update_jmethod_id(jmeths, method, idnum);
2698     }
2699   }
2700   return id;
2701 }
2702 
2703 void InstanceKlass::update_methods_jmethod_cache() {
2704   assert(SafepointSynchronize::is_at_safepoint(), "only called at safepoint");
2705   jmethodID* cache = _methods_jmethod_ids;
2706   if (cache != nullptr) {
2707     size_t size = idnum_allocated_count();
2708     size_t old_size = (size_t)cache[0];
2709     if (old_size < size + 1) {
2710       // Allocate a larger one and copy entries to the new one.
2711       // They've already been updated to point to new methods where applicable (i.e., not obsolete).
2712       jmethodID* new_cache = NEW_C_HEAP_ARRAY(jmethodID, size + 1, mtClass);
2713       memset(new_cache, 0, (size + 1) * sizeof(jmethodID));
2714       // The cache size is stored in element[0]; the other elements are offset by one.
2715       new_cache[0] = (jmethodID)size;
2716 
2717       for (int i = 1; i <= (int)old_size; i++) {
2718         new_cache[i] = cache[i];
2719       }
2720       _methods_jmethod_ids = new_cache;
2721       FREE_C_HEAP_ARRAY(jmethodID, cache);
2722     }
2723   }
2724 }
2725 
2726 // Figure out how many jmethodIDs haven't been allocated, and make
2727 // sure space for them is pre-allocated.  This makes getting all
2728 // method ids much, much faster with classes with more than 8
2729 // methods, and has a *substantial* effect on performance with jvmti
2730 // code that loads all jmethodIDs for all classes.
2731 void InstanceKlass::ensure_space_for_methodids(int start_offset) {
2732   int new_jmeths = 0;
2733   int length = methods()->length();
2734   for (int index = start_offset; index < length; index++) {
2735     Method* m = methods()->at(index);
2736     jmethodID id = m->find_jmethod_id_or_null();
2737     if (id == nullptr) {
2738       new_jmeths++;
2739     }
2740   }
2741   if (new_jmeths != 0) {
2742     Method::ensure_jmethod_ids(class_loader_data(), new_jmeths);
2743   }
2744 }
2745 
2746 // Lookup a jmethodID, null if not found.  Do no blocking, no allocations, no handles
2747 jmethodID InstanceKlass::jmethod_id_or_null(Method* method) {
2748   int idnum = method->method_idnum();
2749   jmethodID* jmeths = methods_jmethod_ids_acquire();
2750   return (jmeths != nullptr) ? jmeths[idnum + 1] : nullptr;
2751 }
2752 
2753 inline DependencyContext InstanceKlass::dependencies() {
2754   DependencyContext dep_context(&_dep_context, &_dep_context_last_cleaned);
2755   return dep_context;
2756 }
2757 
2758 void InstanceKlass::mark_dependent_nmethods(DeoptimizationScope* deopt_scope, KlassDepChange& changes) {
2759   dependencies().mark_dependent_nmethods(deopt_scope, changes);
2760 }
2761 
2762 void InstanceKlass::add_dependent_nmethod(nmethod* nm) {
2763   dependencies().add_dependent_nmethod(nm);
2764 }
2765 
2766 void InstanceKlass::clean_dependency_context() {
2767   dependencies().clean_unloading_dependents();
2768 }
2769 
2770 #ifndef PRODUCT
2771 void InstanceKlass::print_dependent_nmethods(bool verbose) {
2772   dependencies().print_dependent_nmethods(verbose);
2773 }
2774 
2775 bool InstanceKlass::is_dependent_nmethod(nmethod* nm) {
2776   return dependencies().is_dependent_nmethod(nm);
2777 }
2778 #endif //PRODUCT
2779 
2780 void InstanceKlass::clean_weak_instanceklass_links() {
2781   clean_implementors_list();
2782   clean_method_data();
2783 }
2784 
2785 void InstanceKlass::clean_implementors_list() {
2786   assert(is_loader_alive(), "this klass should be live");
2787   if (is_interface()) {
2788     assert (ClassUnloading, "only called for ClassUnloading");
2789     for (;;) {
2790       // Use load_acquire due to competing with inserts
2791       InstanceKlass* volatile* iklass = adr_implementor();
2792       assert(iklass != nullptr, "Klass must not be null");
2793       InstanceKlass* impl = Atomic::load_acquire(iklass);
2794       if (impl != nullptr && !impl->is_loader_alive()) {
2795         // null this field, might be an unloaded instance klass or null
2796         if (Atomic::cmpxchg(iklass, impl, (InstanceKlass*)nullptr) == impl) {
2797           // Successfully unlinking implementor.
2798           if (log_is_enabled(Trace, class, unload)) {
2799             ResourceMark rm;
2800             log_trace(class, unload)("unlinking class (implementor): %s", impl->external_name());
2801           }
2802           return;
2803         }
2804       } else {
2805         return;
2806       }
2807     }
2808   }
2809 }
2810 
2811 void InstanceKlass::clean_method_data() {
2812   for (int m = 0; m < methods()->length(); m++) {
2813     MethodData* mdo = methods()->at(m)->method_data();
2814     if (mdo != nullptr) {
2815       mdo->clean_method_data(/*always_clean*/false);
2816     }
2817   }
2818 }
2819 
2820 void InstanceKlass::metaspace_pointers_do(MetaspaceClosure* it) {
2821   Klass::metaspace_pointers_do(it);
2822 
2823   if (log_is_enabled(Trace, cds)) {
2824     ResourceMark rm;
2825     log_trace(cds)("Iter(InstanceKlass): %p (%s)", this, external_name());
2826   }
2827 
2828   it->push(&_annotations);
2829   it->push((Klass**)&_array_klasses);
2830   if (!is_rewritten()) {
2831     it->push(&_constants, MetaspaceClosure::_writable);
2832   } else {
2833     it->push(&_constants);
2834   }
2835   it->push(&_inner_classes);
2836 #if INCLUDE_JVMTI
2837   it->push(&_previous_versions);
2838 #endif
2839 #if INCLUDE_CDS
2840   // For "old" classes with methods containing the jsr bytecode, the _methods array will
2841   // be rewritten during runtime (see Rewriter::rewrite_jsrs()) but they cannot be safely
2842   // checked here with ByteCodeStream. All methods that can't be verified are made writable.
2843   // The length check on the _methods is necessary because classes which don't have any
2844   // methods share the Universe::_the_empty_method_array which is in the RO region.
2845   if (_methods != nullptr && _methods->length() > 0 && !can_be_verified_at_dumptime()) {
2846     // To handle jsr bytecode, new Method* maybe stored into _methods
2847     it->push(&_methods, MetaspaceClosure::_writable);
2848   } else {
2849 #endif
2850     it->push(&_methods);
2851 #if INCLUDE_CDS
2852   }
2853 #endif
2854   it->push(&_default_methods);
2855   it->push(&_local_interfaces);
2856   it->push(&_transitive_interfaces);
2857   it->push(&_method_ordering);
2858   if (!is_rewritten()) {
2859     it->push(&_default_vtable_indices, MetaspaceClosure::_writable);
2860   } else {
2861     it->push(&_default_vtable_indices);
2862   }
2863 
2864   it->push(&_fieldinfo_stream);
2865   // _fields_status might be written into by Rewriter::scan_method() -> fd.set_has_initialized_final_update()
2866   it->push(&_fields_status, MetaspaceClosure::_writable);
2867 
2868   if (itable_length() > 0) {
2869     itableOffsetEntry* ioe = (itableOffsetEntry*)start_of_itable();
2870     int method_table_offset_in_words = ioe->offset()/wordSize;
2871     int itable_offset_in_words = (int)(start_of_itable() - (intptr_t*)this);
2872 
2873     int nof_interfaces = (method_table_offset_in_words - itable_offset_in_words)
2874                          / itableOffsetEntry::size();
2875 
2876     for (int i = 0; i < nof_interfaces; i ++, ioe ++) {
2877       if (ioe->interface_klass() != nullptr) {
2878         it->push(ioe->interface_klass_addr());
2879         itableMethodEntry* ime = ioe->first_method_entry(this);
2880         int n = klassItable::method_count_for_interface(ioe->interface_klass());
2881         for (int index = 0; index < n; index ++) {
2882           it->push(ime[index].method_addr());
2883         }
2884       }
2885     }
2886   }
2887 
2888   it->push(&_nest_host);
2889   it->push(&_nest_members);
2890   it->push(&_permitted_subclasses);
2891   it->push(&_loadable_descriptors);
2892   it->push(&_record_components);
2893   it->push(&_inline_layout_info_array, MetaspaceClosure::_writable);
2894 }
2895 
2896 #if INCLUDE_CDS
2897 void InstanceKlass::remove_unshareable_info() {
2898 
2899   if (is_linked()) {
2900     assert(can_be_verified_at_dumptime(), "must be");
2901     // Remember this so we can avoid walking the hierarchy at runtime.
2902     set_verified_at_dump_time();
2903   }
2904 
2905   Klass::remove_unshareable_info();
2906 
2907   if (SystemDictionaryShared::has_class_failed_verification(this)) {
2908     // Classes are attempted to link during dumping and may fail,
2909     // but these classes are still in the dictionary and class list in CLD.
2910     // If the class has failed verification, there is nothing else to remove.
2911     return;
2912   }
2913 
2914   // Reset to the 'allocated' state to prevent any premature accessing to
2915   // a shared class at runtime while the class is still being loaded and
2916   // restored. A class' init_state is set to 'loaded' at runtime when it's
2917   // being added to class hierarchy (see InstanceKlass:::add_to_hierarchy()).
2918   _init_state = allocated;
2919 
2920   { // Otherwise this needs to take out the Compile_lock.
2921     assert(SafepointSynchronize::is_at_safepoint(), "only called at safepoint");
2922     init_implementor();
2923   }
2924 
2925   // Call remove_unshareable_info() on other objects that belong to this class, except
2926   // for constants()->remove_unshareable_info(), which is called in a separate pass in
2927   // ArchiveBuilder::make_klasses_shareable(),
2928 
2929   for (int i = 0; i < methods()->length(); i++) {
2930     Method* m = methods()->at(i);
2931     m->remove_unshareable_info();
2932   }
2933 
2934   // do array classes also.
2935   if (array_klasses() != nullptr) {
2936     array_klasses()->remove_unshareable_info();
2937   }
2938 
2939   // These are not allocated from metaspace. They are safe to set to nullptr.
2940   _source_debug_extension = nullptr;
2941   _dep_context = nullptr;
2942   _osr_nmethods_head = nullptr;
2943 #if INCLUDE_JVMTI
2944   _breakpoints = nullptr;
2945   _previous_versions = nullptr;
2946   _cached_class_file = nullptr;
2947   _jvmti_cached_class_field_map = nullptr;
2948 #endif
2949 
2950   _init_thread = nullptr;
2951   _methods_jmethod_ids = nullptr;
2952   _jni_ids = nullptr;
2953   _oop_map_cache = nullptr;
2954   if (CDSConfig::is_dumping_invokedynamic() && HeapShared::is_lambda_proxy_klass(this)) {
2955     // keep _nest_host
2956   } else {
2957     // clear _nest_host to ensure re-load at runtime
2958     _nest_host = nullptr;
2959   }
2960   init_shared_package_entry();
2961   _dep_context_last_cleaned = 0;
2962 
2963   remove_unshareable_flags();
2964 }
2965 
2966 void InstanceKlass::remove_unshareable_flags() {
2967   // clear all the flags/stats that shouldn't be in the archived version
2968   assert(!is_scratch_class(), "must be");
2969   assert(!has_been_redefined(), "must be");
2970 #if INCLUDE_JVMTI
2971   set_is_being_redefined(false);
2972 #endif
2973   set_has_resolved_methods(false);
2974 }
2975 
2976 void InstanceKlass::remove_java_mirror() {
2977   Klass::remove_java_mirror();
2978 
2979   // do array classes also.
2980   if (array_klasses() != nullptr) {
2981     array_klasses()->remove_java_mirror();
2982   }
2983 }
2984 
2985 void InstanceKlass::init_shared_package_entry() {
2986   assert(CDSConfig::is_dumping_archive(), "must be");
2987 #if !INCLUDE_CDS_JAVA_HEAP
2988   _package_entry = nullptr;
2989 #else
2990   if (CDSConfig::is_dumping_full_module_graph()) {
2991     if (is_shared_unregistered_class()) {
2992       _package_entry = nullptr;
2993     } else {
2994       _package_entry = PackageEntry::get_archived_entry(_package_entry);
2995     }
2996   } else if (CDSConfig::is_dumping_dynamic_archive() &&
2997              CDSConfig::is_using_full_module_graph() &&
2998              MetaspaceShared::is_in_shared_metaspace(_package_entry)) {
2999     // _package_entry is an archived package in the base archive. Leave it as is.
3000   } else {
3001     _package_entry = nullptr;
3002   }
3003   ArchivePtrMarker::mark_pointer((address**)&_package_entry);
3004 #endif
3005 }
3006 
3007 void InstanceKlass::compute_has_loops_flag_for_methods() {
3008   Array<Method*>* methods = this->methods();
3009   for (int index = 0; index < methods->length(); ++index) {
3010     Method* m = methods->at(index);
3011     if (!m->is_overpass()) { // work around JDK-8305771
3012       m->compute_has_loops_flag();
3013     }
3014   }
3015 }
3016 
3017 void InstanceKlass::restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain,
3018                                              PackageEntry* pkg_entry, TRAPS) {
3019   // InstanceKlass::add_to_hierarchy() sets the init_state to loaded
3020   // before the InstanceKlass is added to the SystemDictionary. Make
3021   // sure the current state is <loaded.
3022   assert(!is_loaded(), "invalid init state");
3023   assert(!shared_loading_failed(), "Must not try to load failed class again");
3024   set_package(loader_data, pkg_entry, CHECK);
3025   Klass::restore_unshareable_info(loader_data, protection_domain, CHECK);
3026 
3027   if (is_inline_klass()) {
3028     InlineKlass::cast(this)->initialize_calling_convention(CHECK);
3029   }
3030 
3031   Array<Method*>* methods = this->methods();
3032   int num_methods = methods->length();
3033   for (int index = 0; index < num_methods; ++index) {
3034     methods->at(index)->restore_unshareable_info(CHECK);
3035   }
3036 #if INCLUDE_JVMTI
3037   if (JvmtiExport::has_redefined_a_class()) {
3038     // Reinitialize vtable because RedefineClasses may have changed some
3039     // entries in this vtable for super classes so the CDS vtable might
3040     // point to old or obsolete entries.  RedefineClasses doesn't fix up
3041     // vtables in the shared system dictionary, only the main one.
3042     // It also redefines the itable too so fix that too.
3043     // First fix any default methods that point to a super class that may
3044     // have been redefined.
3045     bool trace_name_printed = false;
3046     adjust_default_methods(&trace_name_printed);
3047     if (verified_at_dump_time()) {
3048       // Initialize vtable and itable for classes which can be verified at dump time.
3049       // Unlinked classes such as old classes with major version < 50 cannot be verified
3050       // at dump time.
3051       vtable().initialize_vtable();
3052       itable().initialize_itable();
3053     }
3054   }
3055 #endif // INCLUDE_JVMTI
3056 
3057   // restore constant pool resolved references
3058   constants()->restore_unshareable_info(CHECK);
3059 
3060   if (array_klasses() != nullptr) {
3061     // To get a consistent list of classes we need MultiArray_lock to ensure
3062     // array classes aren't observed while they are being restored.
3063     RecursiveLocker rl(MultiArray_lock, THREAD);
3064     assert(this == ObjArrayKlass::cast(array_klasses())->bottom_klass(), "sanity");
3065     // Array classes have null protection domain.
3066     // --> see ArrayKlass::complete_create_array_klass()
3067     array_klasses()->restore_unshareable_info(class_loader_data(), Handle(), CHECK);
3068   }
3069 
3070   // Initialize @ValueBased class annotation if not already set in the archived klass.
3071   if (DiagnoseSyncOnValueBasedClasses && has_value_based_class_annotation() && !is_value_based()) {
3072     set_is_value_based();
3073   }
3074 }
3075 
3076 // Check if a class or any of its supertypes has a version older than 50.
3077 // CDS will not perform verification of old classes during dump time because
3078 // without changing the old verifier, the verification constraint cannot be
3079 // retrieved during dump time.
3080 // Verification of archived old classes will be performed during run time.
3081 bool InstanceKlass::can_be_verified_at_dumptime() const {
3082   if (MetaspaceShared::is_in_shared_metaspace(this)) {
3083     // This is a class that was dumped into the base archive, so we know
3084     // it was verified at dump time.
3085     return true;
3086   }
3087   if (major_version() < 50 /*JAVA_6_VERSION*/) {
3088     return false;
3089   }
3090   if (java_super() != nullptr && !java_super()->can_be_verified_at_dumptime()) {
3091     return false;
3092   }
3093   Array<InstanceKlass*>* interfaces = local_interfaces();
3094   int len = interfaces->length();
3095   for (int i = 0; i < len; i++) {
3096     if (!interfaces->at(i)->can_be_verified_at_dumptime()) {
3097       return false;
3098     }
3099   }
3100   return true;
3101 }
3102 
3103 int InstanceKlass::shared_class_loader_type() const {
3104   if (is_shared_boot_class()) {
3105     return ClassLoader::BOOT_LOADER;
3106   } else if (is_shared_platform_class()) {
3107     return ClassLoader::PLATFORM_LOADER;
3108   } else if (is_shared_app_class()) {
3109     return ClassLoader::APP_LOADER;
3110   } else {
3111     return ClassLoader::OTHER;
3112   }
3113 }
3114 #endif // INCLUDE_CDS
3115 
3116 #if INCLUDE_JVMTI
3117 static void clear_all_breakpoints(Method* m) {
3118   m->clear_all_breakpoints();
3119 }
3120 #endif
3121 
3122 void InstanceKlass::unload_class(InstanceKlass* ik) {
3123 
3124   if (ik->is_scratch_class()) {
3125     assert(ik->dependencies().is_empty(), "dependencies should be empty for scratch classes");
3126     return;
3127   }
3128   assert(ik->is_loaded(), "class should be loaded " PTR_FORMAT, p2i(ik));
3129 
3130   // Release dependencies.
3131   ik->dependencies().remove_all_dependents();
3132 
3133   // notify the debugger
3134   if (JvmtiExport::should_post_class_unload()) {
3135     JvmtiExport::post_class_unload(ik);
3136   }
3137 
3138   // notify ClassLoadingService of class unload
3139   ClassLoadingService::notify_class_unloaded(ik);
3140 
3141   SystemDictionaryShared::handle_class_unloading(ik);
3142 
3143   if (log_is_enabled(Info, class, unload)) {
3144     ResourceMark rm;
3145     log_info(class, unload)("unloading class %s " PTR_FORMAT, ik->external_name(), p2i(ik));
3146   }
3147 
3148   Events::log_class_unloading(Thread::current(), ik);
3149 
3150 #if INCLUDE_JFR
3151   assert(ik != nullptr, "invariant");
3152   EventClassUnload event;
3153   event.set_unloadedClass(ik);
3154   event.set_definingClassLoader(ik->class_loader_data());
3155   event.commit();
3156 #endif
3157 }
3158 
3159 static void method_release_C_heap_structures(Method* m) {
3160   m->release_C_heap_structures();
3161 }
3162 
3163 // Called also by InstanceKlass::deallocate_contents, with false for release_sub_metadata.
3164 void InstanceKlass::release_C_heap_structures(bool release_sub_metadata) {
3165   // Clean up C heap
3166   Klass::release_C_heap_structures();
3167 
3168   // Deallocate and call destructors for MDO mutexes
3169   if (release_sub_metadata) {
3170     methods_do(method_release_C_heap_structures);
3171   }
3172 
3173   // Deallocate oop map cache
3174   if (_oop_map_cache != nullptr) {
3175     delete _oop_map_cache;
3176     _oop_map_cache = nullptr;
3177   }
3178 
3179   // Deallocate JNI identifiers for jfieldIDs
3180   JNIid::deallocate(jni_ids());
3181   set_jni_ids(nullptr);
3182 
3183   jmethodID* jmeths = methods_jmethod_ids_acquire();
3184   if (jmeths != nullptr) {
3185     release_set_methods_jmethod_ids(nullptr);
3186     FreeHeap(jmeths);
3187   }
3188 
3189   assert(_dep_context == nullptr,
3190          "dependencies should already be cleaned");
3191 
3192 #if INCLUDE_JVMTI
3193   // Deallocate breakpoint records
3194   if (breakpoints() != nullptr) {
3195     methods_do(clear_all_breakpoints);
3196     assert(breakpoints() == nullptr, "should have cleared breakpoints");
3197   }
3198 
3199   // deallocate the cached class file
3200   if (_cached_class_file != nullptr) {
3201     os::free(_cached_class_file);
3202     _cached_class_file = nullptr;
3203   }
3204 #endif
3205 
3206   FREE_C_HEAP_ARRAY(char, _source_debug_extension);
3207 
3208   if (release_sub_metadata) {
3209     constants()->release_C_heap_structures();
3210   }
3211 }
3212 
3213 // The constant pool is on stack if any of the methods are executing or
3214 // referenced by handles.
3215 bool InstanceKlass::on_stack() const {
3216   return _constants->on_stack();
3217 }
3218 
3219 Symbol* InstanceKlass::source_file_name() const               { return _constants->source_file_name(); }
3220 u2 InstanceKlass::source_file_name_index() const              { return _constants->source_file_name_index(); }
3221 void InstanceKlass::set_source_file_name_index(u2 sourcefile_index) { _constants->set_source_file_name_index(sourcefile_index); }
3222 
3223 // minor and major version numbers of class file
3224 u2 InstanceKlass::minor_version() const                 { return _constants->minor_version(); }
3225 void InstanceKlass::set_minor_version(u2 minor_version) { _constants->set_minor_version(minor_version); }
3226 u2 InstanceKlass::major_version() const                 { return _constants->major_version(); }
3227 void InstanceKlass::set_major_version(u2 major_version) { _constants->set_major_version(major_version); }
3228 
3229 InstanceKlass* InstanceKlass::get_klass_version(int version) {
3230   for (InstanceKlass* ik = this; ik != nullptr; ik = ik->previous_versions()) {
3231     if (ik->constants()->version() == version) {
3232       return ik;
3233     }
3234   }
3235   return nullptr;
3236 }
3237 
3238 void InstanceKlass::set_source_debug_extension(const char* array, int length) {
3239   if (array == nullptr) {
3240     _source_debug_extension = nullptr;
3241   } else {
3242     // Adding one to the attribute length in order to store a null terminator
3243     // character could cause an overflow because the attribute length is
3244     // already coded with an u4 in the classfile, but in practice, it's
3245     // unlikely to happen.
3246     assert((length+1) > length, "Overflow checking");
3247     char* sde = NEW_C_HEAP_ARRAY(char, (length + 1), mtClass);
3248     for (int i = 0; i < length; i++) {
3249       sde[i] = array[i];
3250     }
3251     sde[length] = '\0';
3252     _source_debug_extension = sde;
3253   }
3254 }
3255 
3256 Symbol* InstanceKlass::generic_signature() const                   { return _constants->generic_signature(); }
3257 u2 InstanceKlass::generic_signature_index() const                  { return _constants->generic_signature_index(); }
3258 void InstanceKlass::set_generic_signature_index(u2 sig_index)      { _constants->set_generic_signature_index(sig_index); }
3259 
3260 const char* InstanceKlass::signature_name() const {
3261   return signature_name_of_carrier(JVM_SIGNATURE_CLASS);
3262 }
3263 
3264 const char* InstanceKlass::signature_name_of_carrier(char c) const {
3265   // Get the internal name as a c string
3266   const char* src = (const char*) (name()->as_C_string());
3267   const int src_length = (int)strlen(src);
3268 
3269   char* dest = NEW_RESOURCE_ARRAY(char, src_length + 3);
3270 
3271   // Add L or Q as type indicator
3272   int dest_index = 0;
3273   dest[dest_index++] = c;
3274 
3275   // Add the actual class name
3276   for (int src_index = 0; src_index < src_length; ) {
3277     dest[dest_index++] = src[src_index++];
3278   }
3279 
3280   if (is_hidden()) { // Replace the last '+' with a '.'.
3281     for (int index = (int)src_length; index > 0; index--) {
3282       if (dest[index] == '+') {
3283         dest[index] = JVM_SIGNATURE_DOT;
3284         break;
3285       }
3286     }
3287   }
3288 
3289   // Add the semicolon and the null
3290   dest[dest_index++] = JVM_SIGNATURE_ENDCLASS;
3291   dest[dest_index] = '\0';
3292   return dest;
3293 }
3294 
3295 ModuleEntry* InstanceKlass::module() const {
3296   if (is_hidden() &&
3297       in_unnamed_package() &&
3298       class_loader_data()->has_class_mirror_holder()) {
3299     // For a non-strong hidden class defined to an unnamed package,
3300     // its (class held) CLD will not have an unnamed module created for it.
3301     // Two choices to find the correct ModuleEntry:
3302     // 1. If hidden class is within a nest, use nest host's module
3303     // 2. Find the unnamed module off from the class loader
3304     // For now option #2 is used since a nest host is not set until
3305     // after the instance class is created in jvm_lookup_define_class().
3306     if (class_loader_data()->is_boot_class_loader_data()) {
3307       return ClassLoaderData::the_null_class_loader_data()->unnamed_module();
3308     } else {
3309       oop module = java_lang_ClassLoader::unnamedModule(class_loader_data()->class_loader());
3310       assert(java_lang_Module::is_instance(module), "Not an instance of java.lang.Module");
3311       return java_lang_Module::module_entry(module);
3312     }
3313   }
3314 
3315   // Class is in a named package
3316   if (!in_unnamed_package()) {
3317     return _package_entry->module();
3318   }
3319 
3320   // Class is in an unnamed package, return its loader's unnamed module
3321   return class_loader_data()->unnamed_module();
3322 }
3323 
3324 bool InstanceKlass::in_javabase_module() const {
3325   return module()->name() == vmSymbols::java_base();
3326 }
3327 
3328 void InstanceKlass::set_package(ClassLoaderData* loader_data, PackageEntry* pkg_entry, TRAPS) {
3329 
3330   // ensure java/ packages only loaded by boot or platform builtin loaders
3331   // not needed for shared class since CDS does not archive prohibited classes.
3332   if (!is_shared()) {
3333     check_prohibited_package(name(), loader_data, CHECK);
3334   }
3335 
3336   if (is_shared() && _package_entry != nullptr) {
3337     if (CDSConfig::is_using_full_module_graph() && _package_entry == pkg_entry) {
3338       // we can use the saved package
3339       assert(MetaspaceShared::is_in_shared_metaspace(_package_entry), "must be");
3340       return;
3341     } else {
3342       _package_entry = nullptr;
3343     }
3344   }
3345 
3346   // ClassLoader::package_from_class_name has already incremented the refcount of the symbol
3347   // it returns, so we need to decrement it when the current function exits.
3348   TempNewSymbol from_class_name =
3349       (pkg_entry != nullptr) ? nullptr : ClassLoader::package_from_class_name(name());
3350 
3351   Symbol* pkg_name;
3352   if (pkg_entry != nullptr) {
3353     pkg_name = pkg_entry->name();
3354   } else {
3355     pkg_name = from_class_name;
3356   }
3357 
3358   if (pkg_name != nullptr && loader_data != nullptr) {
3359 
3360     // Find in class loader's package entry table.
3361     _package_entry = pkg_entry != nullptr ? pkg_entry : loader_data->packages()->lookup_only(pkg_name);
3362 
3363     // If the package name is not found in the loader's package
3364     // entry table, it is an indication that the package has not
3365     // been defined. Consider it defined within the unnamed module.
3366     if (_package_entry == nullptr) {
3367 
3368       if (!ModuleEntryTable::javabase_defined()) {
3369         // Before java.base is defined during bootstrapping, define all packages in
3370         // the java.base module.  If a non-java.base package is erroneously placed
3371         // in the java.base module it will be caught later when java.base
3372         // is defined by ModuleEntryTable::verify_javabase_packages check.
3373         assert(ModuleEntryTable::javabase_moduleEntry() != nullptr, JAVA_BASE_NAME " module is null");
3374         _package_entry = loader_data->packages()->create_entry_if_absent(pkg_name, ModuleEntryTable::javabase_moduleEntry());
3375       } else {
3376         assert(loader_data->unnamed_module() != nullptr, "unnamed module is null");
3377         _package_entry = loader_data->packages()->create_entry_if_absent(pkg_name, loader_data->unnamed_module());
3378       }
3379 
3380       // A package should have been successfully created
3381       DEBUG_ONLY(ResourceMark rm(THREAD));
3382       assert(_package_entry != nullptr, "Package entry for class %s not found, loader %s",
3383              name()->as_C_string(), loader_data->loader_name_and_id());
3384     }
3385 
3386     if (log_is_enabled(Debug, module)) {
3387       ResourceMark rm(THREAD);
3388       ModuleEntry* m = _package_entry->module();
3389       log_trace(module)("Setting package: class: %s, package: %s, loader: %s, module: %s",
3390                         external_name(),
3391                         pkg_name->as_C_string(),
3392                         loader_data->loader_name_and_id(),
3393                         (m->is_named() ? m->name()->as_C_string() : UNNAMED_MODULE));
3394     }
3395   } else {
3396     ResourceMark rm(THREAD);
3397     log_trace(module)("Setting package: class: %s, package: unnamed, loader: %s, module: %s",
3398                       external_name(),
3399                       (loader_data != nullptr) ? loader_data->loader_name_and_id() : "null",
3400                       UNNAMED_MODULE);
3401   }
3402 }
3403 
3404 // Function set_classpath_index ensures that for a non-null _package_entry
3405 // of the InstanceKlass, the entry is in the boot loader's package entry table.
3406 // It then sets the classpath_index in the package entry record.
3407 //
3408 // The classpath_index field is used to find the entry on the boot loader class
3409 // path for packages with classes loaded by the boot loader from -Xbootclasspath/a
3410 // in an unnamed module.  It is also used to indicate (for all packages whose
3411 // classes are loaded by the boot loader) that at least one of the package's
3412 // classes has been loaded.
3413 void InstanceKlass::set_classpath_index(s2 path_index) {
3414   if (_package_entry != nullptr) {
3415     DEBUG_ONLY(PackageEntryTable* pkg_entry_tbl = ClassLoaderData::the_null_class_loader_data()->packages();)
3416     assert(pkg_entry_tbl->lookup_only(_package_entry->name()) == _package_entry, "Should be same");
3417     assert(path_index != -1, "Unexpected classpath_index");
3418     _package_entry->set_classpath_index(path_index);
3419   }
3420 }
3421 
3422 // different versions of is_same_class_package
3423 
3424 bool InstanceKlass::is_same_class_package(const Klass* class2) const {
3425   oop classloader1 = this->class_loader();
3426   PackageEntry* classpkg1 = this->package();
3427   if (class2->is_objArray_klass()) {
3428     class2 = ObjArrayKlass::cast(class2)->bottom_klass();
3429   }
3430 
3431   oop classloader2;
3432   PackageEntry* classpkg2;
3433   if (class2->is_instance_klass()) {
3434     classloader2 = class2->class_loader();
3435     classpkg2 = class2->package();
3436   } else {
3437     assert(class2->is_typeArray_klass(), "should be type array");
3438     classloader2 = nullptr;
3439     classpkg2 = nullptr;
3440   }
3441 
3442   // Same package is determined by comparing class loader
3443   // and package entries. Both must be the same. This rule
3444   // applies even to classes that are defined in the unnamed
3445   // package, they still must have the same class loader.
3446   if ((classloader1 == classloader2) && (classpkg1 == classpkg2)) {
3447     return true;
3448   }
3449 
3450   return false;
3451 }
3452 
3453 // return true if this class and other_class are in the same package. Classloader
3454 // and classname information is enough to determine a class's package
3455 bool InstanceKlass::is_same_class_package(oop other_class_loader,
3456                                           const Symbol* other_class_name) const {
3457   if (class_loader() != other_class_loader) {
3458     return false;
3459   }
3460   if (name()->fast_compare(other_class_name) == 0) {
3461      return true;
3462   }
3463 
3464   {
3465     ResourceMark rm;
3466 
3467     bool bad_class_name = false;
3468     TempNewSymbol other_pkg = ClassLoader::package_from_class_name(other_class_name, &bad_class_name);
3469     if (bad_class_name) {
3470       return false;
3471     }
3472     // Check that package_from_class_name() returns null, not "", if there is no package.
3473     assert(other_pkg == nullptr || other_pkg->utf8_length() > 0, "package name is empty string");
3474 
3475     const Symbol* const this_package_name =
3476       this->package() != nullptr ? this->package()->name() : nullptr;
3477 
3478     if (this_package_name == nullptr || other_pkg == nullptr) {
3479       // One of the two doesn't have a package.  Only return true if the other
3480       // one also doesn't have a package.
3481       return this_package_name == other_pkg;
3482     }
3483 
3484     // Check if package is identical
3485     return this_package_name->fast_compare(other_pkg) == 0;
3486   }
3487 }
3488 
3489 static bool is_prohibited_package_slow(Symbol* class_name) {
3490   // Caller has ResourceMark
3491   int length;
3492   jchar* unicode = class_name->as_unicode(length);
3493   return (length >= 5 &&
3494           unicode[0] == 'j' &&
3495           unicode[1] == 'a' &&
3496           unicode[2] == 'v' &&
3497           unicode[3] == 'a' &&
3498           unicode[4] == '/');
3499 }
3500 
3501 // Only boot and platform class loaders can define classes in "java/" packages.
3502 void InstanceKlass::check_prohibited_package(Symbol* class_name,
3503                                              ClassLoaderData* loader_data,
3504                                              TRAPS) {
3505   if (!loader_data->is_boot_class_loader_data() &&
3506       !loader_data->is_platform_class_loader_data() &&
3507       class_name != nullptr && class_name->utf8_length() >= 5) {
3508     ResourceMark rm(THREAD);
3509     bool prohibited;
3510     const u1* base = class_name->base();
3511     if ((base[0] | base[1] | base[2] | base[3] | base[4]) & 0x80) {
3512       prohibited = is_prohibited_package_slow(class_name);
3513     } else {
3514       char* name = class_name->as_C_string();
3515       prohibited = (strncmp(name, JAVAPKG, JAVAPKG_LEN) == 0 && name[JAVAPKG_LEN] == '/');
3516     }
3517     if (prohibited) {
3518       TempNewSymbol pkg_name = ClassLoader::package_from_class_name(class_name);
3519       assert(pkg_name != nullptr, "Error in parsing package name starting with 'java/'");
3520       char* name = pkg_name->as_C_string();
3521       const char* class_loader_name = loader_data->loader_name_and_id();
3522       StringUtils::replace_no_expand(name, "/", ".");
3523       const char* msg_text1 = "Class loader (instance of): ";
3524       const char* msg_text2 = " tried to load prohibited package name: ";
3525       size_t len = strlen(msg_text1) + strlen(class_loader_name) + strlen(msg_text2) + strlen(name) + 1;
3526       char* message = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, len);
3527       jio_snprintf(message, len, "%s%s%s%s", msg_text1, class_loader_name, msg_text2, name);
3528       THROW_MSG(vmSymbols::java_lang_SecurityException(), message);
3529     }
3530   }
3531   return;
3532 }
3533 
3534 bool InstanceKlass::find_inner_classes_attr(int* ooff, int* noff, TRAPS) const {
3535   constantPoolHandle i_cp(THREAD, constants());
3536   for (InnerClassesIterator iter(this); !iter.done(); iter.next()) {
3537     int ioff = iter.inner_class_info_index();
3538     if (ioff != 0) {
3539       // Check to see if the name matches the class we're looking for
3540       // before attempting to find the class.
3541       if (i_cp->klass_name_at_matches(this, ioff)) {
3542         Klass* inner_klass = i_cp->klass_at(ioff, CHECK_false);
3543         if (this == inner_klass) {
3544           *ooff = iter.outer_class_info_index();
3545           *noff = iter.inner_name_index();
3546           return true;
3547         }
3548       }
3549     }
3550   }
3551   return false;
3552 }
3553 
3554 InstanceKlass* InstanceKlass::compute_enclosing_class(bool* inner_is_member, TRAPS) const {
3555   InstanceKlass* outer_klass = nullptr;
3556   *inner_is_member = false;
3557   int ooff = 0, noff = 0;
3558   bool has_inner_classes_attr = find_inner_classes_attr(&ooff, &noff, THREAD);
3559   if (has_inner_classes_attr) {
3560     constantPoolHandle i_cp(THREAD, constants());
3561     if (ooff != 0) {
3562       Klass* ok = i_cp->klass_at(ooff, CHECK_NULL);
3563       if (!ok->is_instance_klass()) {
3564         // If the outer class is not an instance klass then it cannot have
3565         // declared any inner classes.
3566         ResourceMark rm(THREAD);
3567         // Names are all known to be < 64k so we know this formatted message is not excessively large.
3568         Exceptions::fthrow(
3569           THREAD_AND_LOCATION,
3570           vmSymbols::java_lang_IncompatibleClassChangeError(),
3571           "%s and %s disagree on InnerClasses attribute",
3572           ok->external_name(),
3573           external_name());
3574         return nullptr;
3575       }
3576       outer_klass = InstanceKlass::cast(ok);
3577       *inner_is_member = true;
3578     }
3579     if (nullptr == outer_klass) {
3580       // It may be a local class; try for that.
3581       int encl_method_class_idx = enclosing_method_class_index();
3582       if (encl_method_class_idx != 0) {
3583         Klass* ok = i_cp->klass_at(encl_method_class_idx, CHECK_NULL);
3584         outer_klass = InstanceKlass::cast(ok);
3585         *inner_is_member = false;
3586       }
3587     }
3588   }
3589 
3590   // If no inner class attribute found for this class.
3591   if (nullptr == outer_klass) return nullptr;
3592 
3593   // Throws an exception if outer klass has not declared k as an inner klass
3594   // We need evidence that each klass knows about the other, or else
3595   // the system could allow a spoof of an inner class to gain access rights.
3596   Reflection::check_for_inner_class(outer_klass, this, *inner_is_member, CHECK_NULL);
3597   return outer_klass;
3598 }
3599 
3600 u2 InstanceKlass::compute_modifier_flags() const {
3601   u2 access = access_flags().as_unsigned_short();
3602 
3603   // But check if it happens to be member class.
3604   InnerClassesIterator iter(this);
3605   for (; !iter.done(); iter.next()) {
3606     int ioff = iter.inner_class_info_index();
3607     // Inner class attribute can be zero, skip it.
3608     // Strange but true:  JVM spec. allows null inner class refs.
3609     if (ioff == 0) continue;
3610 
3611     // only look at classes that are already loaded
3612     // since we are looking for the flags for our self.
3613     Symbol* inner_name = constants()->klass_name_at(ioff);
3614     if (name() == inner_name) {
3615       // This is really a member class.
3616       access = iter.inner_access_flags();
3617       break;
3618     }
3619   }
3620   return access;
3621 }
3622 
3623 jint InstanceKlass::jvmti_class_status() const {
3624   jint result = 0;
3625 
3626   if (is_linked()) {
3627     result |= JVMTI_CLASS_STATUS_VERIFIED | JVMTI_CLASS_STATUS_PREPARED;
3628   }
3629 
3630   if (is_initialized()) {
3631     assert(is_linked(), "Class status is not consistent");
3632     result |= JVMTI_CLASS_STATUS_INITIALIZED;
3633   }
3634   if (is_in_error_state()) {
3635     result |= JVMTI_CLASS_STATUS_ERROR;
3636   }
3637   return result;
3638 }
3639 
3640 Method* InstanceKlass::method_at_itable(InstanceKlass* holder, int index, TRAPS) {
3641   bool implements_interface; // initialized by method_at_itable_or_null
3642   Method* m = method_at_itable_or_null(holder, index,
3643                                        implements_interface); // out parameter
3644   if (m != nullptr) {
3645     assert(implements_interface, "sanity");
3646     return m;
3647   } else if (implements_interface) {
3648     // Throw AbstractMethodError since corresponding itable slot is empty.
3649     THROW_NULL(vmSymbols::java_lang_AbstractMethodError());
3650   } else {
3651     // If the interface isn't implemented by the receiver class,
3652     // the VM should throw IncompatibleClassChangeError.
3653     ResourceMark rm(THREAD);
3654     stringStream ss;
3655     bool same_module = (module() == holder->module());
3656     ss.print("Receiver class %s does not implement "
3657              "the interface %s defining the method to be called "
3658              "(%s%s%s)",
3659              external_name(), holder->external_name(),
3660              (same_module) ? joint_in_module_of_loader(holder) : class_in_module_of_loader(),
3661              (same_module) ? "" : "; ",
3662              (same_module) ? "" : holder->class_in_module_of_loader());
3663     THROW_MSG_NULL(vmSymbols::java_lang_IncompatibleClassChangeError(), ss.as_string());
3664   }
3665 }
3666 
3667 Method* InstanceKlass::method_at_itable_or_null(InstanceKlass* holder, int index, bool& implements_interface) {
3668   klassItable itable(this);
3669   for (int i = 0; i < itable.size_offset_table(); i++) {
3670     itableOffsetEntry* offset_entry = itable.offset_entry(i);
3671     if (offset_entry->interface_klass() == holder) {
3672       implements_interface = true;
3673       itableMethodEntry* ime = offset_entry->first_method_entry(this);
3674       Method* m = ime[index].method();
3675       return m;
3676     }
3677   }
3678   implements_interface = false;
3679   return nullptr; // offset entry not found
3680 }
3681 
3682 int InstanceKlass::vtable_index_of_interface_method(Method* intf_method) {
3683   assert(is_linked(), "required");
3684   assert(intf_method->method_holder()->is_interface(), "not an interface method");
3685   assert(is_subtype_of(intf_method->method_holder()), "interface not implemented");
3686 
3687   int vtable_index = Method::invalid_vtable_index;
3688   Symbol* name = intf_method->name();
3689   Symbol* signature = intf_method->signature();
3690 
3691   // First check in default method array
3692   if (!intf_method->is_abstract() && default_methods() != nullptr) {
3693     int index = find_method_index(default_methods(),
3694                                   name, signature,
3695                                   Klass::OverpassLookupMode::find,
3696                                   Klass::StaticLookupMode::find,
3697                                   Klass::PrivateLookupMode::find);
3698     if (index >= 0) {
3699       vtable_index = default_vtable_indices()->at(index);
3700     }
3701   }
3702   if (vtable_index == Method::invalid_vtable_index) {
3703     // get vtable_index for miranda methods
3704     klassVtable vt = vtable();
3705     vtable_index = vt.index_of_miranda(name, signature);
3706   }
3707   return vtable_index;
3708 }
3709 
3710 #if INCLUDE_JVMTI
3711 // update default_methods for redefineclasses for methods that are
3712 // not yet in the vtable due to concurrent subclass define and superinterface
3713 // redefinition
3714 // Note: those in the vtable, should have been updated via adjust_method_entries
3715 void InstanceKlass::adjust_default_methods(bool* trace_name_printed) {
3716   // search the default_methods for uses of either obsolete or EMCP methods
3717   if (default_methods() != nullptr) {
3718     for (int index = 0; index < default_methods()->length(); index ++) {
3719       Method* old_method = default_methods()->at(index);
3720       if (old_method == nullptr || !old_method->is_old()) {
3721         continue; // skip uninteresting entries
3722       }
3723       assert(!old_method->is_deleted(), "default methods may not be deleted");
3724       Method* new_method = old_method->get_new_method();
3725       default_methods()->at_put(index, new_method);
3726 
3727       if (log_is_enabled(Info, redefine, class, update)) {
3728         ResourceMark rm;
3729         if (!(*trace_name_printed)) {
3730           log_info(redefine, class, update)
3731             ("adjust: klassname=%s default methods from name=%s",
3732              external_name(), old_method->method_holder()->external_name());
3733           *trace_name_printed = true;
3734         }
3735         log_debug(redefine, class, update, vtables)
3736           ("default method update: %s(%s) ",
3737            new_method->name()->as_C_string(), new_method->signature()->as_C_string());
3738       }
3739     }
3740   }
3741 }
3742 #endif // INCLUDE_JVMTI
3743 
3744 // On-stack replacement stuff
3745 void InstanceKlass::add_osr_nmethod(nmethod* n) {
3746   assert_lock_strong(NMethodState_lock);
3747 #ifndef PRODUCT
3748   nmethod* prev = lookup_osr_nmethod(n->method(), n->osr_entry_bci(), n->comp_level(), true);
3749   assert(prev == nullptr || !prev->is_in_use() COMPILER2_PRESENT(|| StressRecompilation),
3750       "redundant OSR recompilation detected. memory leak in CodeCache!");
3751 #endif
3752   // only one compilation can be active
3753   assert(n->is_osr_method(), "wrong kind of nmethod");
3754   n->set_osr_link(osr_nmethods_head());
3755   set_osr_nmethods_head(n);
3756   // Raise the highest osr level if necessary
3757   n->method()->set_highest_osr_comp_level(MAX2(n->method()->highest_osr_comp_level(), n->comp_level()));
3758 
3759   // Get rid of the osr methods for the same bci that have lower levels.
3760   for (int l = CompLevel_limited_profile; l < n->comp_level(); l++) {
3761     nmethod *inv = lookup_osr_nmethod(n->method(), n->osr_entry_bci(), l, true);
3762     if (inv != nullptr && inv->is_in_use()) {
3763       inv->make_not_entrant();
3764     }
3765   }
3766 }
3767 
3768 // Remove osr nmethod from the list. Return true if found and removed.
3769 bool InstanceKlass::remove_osr_nmethod(nmethod* n) {
3770   // This is a short non-blocking critical region, so the no safepoint check is ok.
3771   ConditionalMutexLocker ml(NMethodState_lock, !NMethodState_lock->owned_by_self(), Mutex::_no_safepoint_check_flag);
3772   assert(n->is_osr_method(), "wrong kind of nmethod");
3773   nmethod* last = nullptr;
3774   nmethod* cur  = osr_nmethods_head();
3775   int max_level = CompLevel_none;  // Find the max comp level excluding n
3776   Method* m = n->method();
3777   // Search for match
3778   bool found = false;
3779   while(cur != nullptr && cur != n) {
3780     if (m == cur->method()) {
3781       // Find max level before n
3782       max_level = MAX2(max_level, cur->comp_level());
3783     }
3784     last = cur;
3785     cur = cur->osr_link();
3786   }
3787   nmethod* next = nullptr;
3788   if (cur == n) {
3789     found = true;
3790     next = cur->osr_link();
3791     if (last == nullptr) {
3792       // Remove first element
3793       set_osr_nmethods_head(next);
3794     } else {
3795       last->set_osr_link(next);
3796     }
3797   }
3798   n->set_osr_link(nullptr);
3799   cur = next;
3800   while (cur != nullptr) {
3801     // Find max level after n
3802     if (m == cur->method()) {
3803       max_level = MAX2(max_level, cur->comp_level());
3804     }
3805     cur = cur->osr_link();
3806   }
3807   m->set_highest_osr_comp_level(max_level);
3808   return found;
3809 }
3810 
3811 int InstanceKlass::mark_osr_nmethods(DeoptimizationScope* deopt_scope, const Method* m) {
3812   ConditionalMutexLocker ml(NMethodState_lock, !NMethodState_lock->owned_by_self(), Mutex::_no_safepoint_check_flag);
3813   nmethod* osr = osr_nmethods_head();
3814   int found = 0;
3815   while (osr != nullptr) {
3816     assert(osr->is_osr_method(), "wrong kind of nmethod found in chain");
3817     if (osr->method() == m) {
3818       deopt_scope->mark(osr);
3819       found++;
3820     }
3821     osr = osr->osr_link();
3822   }
3823   return found;
3824 }
3825 
3826 nmethod* InstanceKlass::lookup_osr_nmethod(const Method* m, int bci, int comp_level, bool match_level) const {
3827   ConditionalMutexLocker ml(NMethodState_lock, !NMethodState_lock->owned_by_self(), Mutex::_no_safepoint_check_flag);
3828   nmethod* osr = osr_nmethods_head();
3829   nmethod* best = nullptr;
3830   while (osr != nullptr) {
3831     assert(osr->is_osr_method(), "wrong kind of nmethod found in chain");
3832     // There can be a time when a c1 osr method exists but we are waiting
3833     // for a c2 version. When c2 completes its osr nmethod we will trash
3834     // the c1 version and only be able to find the c2 version. However
3835     // while we overflow in the c1 code at back branches we don't want to
3836     // try and switch to the same code as we are already running
3837 
3838     if (osr->method() == m &&
3839         (bci == InvocationEntryBci || osr->osr_entry_bci() == bci)) {
3840       if (match_level) {
3841         if (osr->comp_level() == comp_level) {
3842           // Found a match - return it.
3843           return osr;
3844         }
3845       } else {
3846         if (best == nullptr || (osr->comp_level() > best->comp_level())) {
3847           if (osr->comp_level() == CompilationPolicy::highest_compile_level()) {
3848             // Found the best possible - return it.
3849             return osr;
3850           }
3851           best = osr;
3852         }
3853       }
3854     }
3855     osr = osr->osr_link();
3856   }
3857 
3858   assert(match_level == false || best == nullptr, "shouldn't pick up anything if match_level is set");
3859   if (best != nullptr && best->comp_level() >= comp_level) {
3860     return best;
3861   }
3862   return nullptr;
3863 }
3864 
3865 // -----------------------------------------------------------------------------------------------------
3866 // Printing
3867 
3868 #define BULLET  " - "
3869 
3870 static const char* state_names[] = {
3871   "allocated", "loaded", "linked", "being_initialized", "fully_initialized", "initialization_error"
3872 };
3873 
3874 static void print_vtable(address self, intptr_t* start, int len, outputStream* st) {
3875   ResourceMark rm;
3876   int* forward_refs = NEW_RESOURCE_ARRAY(int, len);
3877   for (int i = 0; i < len; i++)  forward_refs[i] = 0;
3878   for (int i = 0; i < len; i++) {
3879     intptr_t e = start[i];
3880     st->print("%d : " INTPTR_FORMAT, i, e);
3881     if (forward_refs[i] != 0) {
3882       int from = forward_refs[i];
3883       int off = (int) start[from];
3884       st->print(" (offset %d <= [%d])", off, from);
3885     }
3886     if (MetaspaceObj::is_valid((Metadata*)e)) {
3887       st->print(" ");
3888       ((Metadata*)e)->print_value_on(st);
3889     } else if (self != nullptr && e > 0 && e < 0x10000) {
3890       address location = self + e;
3891       int index = (int)((intptr_t*)location - start);
3892       st->print(" (offset %d => [%d])", (int)e, index);
3893       if (index >= 0 && index < len)
3894         forward_refs[index] = i;
3895     }
3896     st->cr();
3897   }
3898 }
3899 
3900 static void print_vtable(vtableEntry* start, int len, outputStream* st) {
3901   return print_vtable(nullptr, reinterpret_cast<intptr_t*>(start), len, st);
3902 }
3903 
3904 template<typename T>
3905  static void print_array_on(outputStream* st, Array<T>* array) {
3906    if (array == nullptr) { st->print_cr("nullptr"); return; }
3907    array->print_value_on(st); st->cr();
3908    if (Verbose || WizardMode) {
3909      for (int i = 0; i < array->length(); i++) {
3910        st->print("%d : ", i); array->at(i)->print_value_on(st); st->cr();
3911      }
3912    }
3913  }
3914 
3915 static void print_array_on(outputStream* st, Array<int>* array) {
3916   if (array == nullptr) { st->print_cr("nullptr"); return; }
3917   array->print_value_on(st); st->cr();
3918   if (Verbose || WizardMode) {
3919     for (int i = 0; i < array->length(); i++) {
3920       st->print("%d : %d", i, array->at(i)); st->cr();
3921     }
3922   }
3923 }
3924 
3925 const char* InstanceKlass::init_state_name() const {
3926   return state_names[init_state()];
3927 }
3928 
3929 void InstanceKlass::print_on(outputStream* st) const {
3930   assert(is_klass(), "must be klass");
3931   Klass::print_on(st);
3932 
3933   st->print(BULLET"instance size:     %d", size_helper());                        st->cr();
3934   st->print(BULLET"klass size:        %d", size());                               st->cr();
3935   st->print(BULLET"access:            "); access_flags().print_on(st);            st->cr();
3936   st->print(BULLET"flags:             "); _misc_flags.print_on(st);               st->cr();
3937   st->print(BULLET"state:             "); st->print_cr("%s", init_state_name());
3938   st->print(BULLET"name:              "); name()->print_value_on(st);             st->cr();
3939   st->print(BULLET"super:             "); Metadata::print_value_on_maybe_null(st, super()); st->cr();
3940   st->print(BULLET"sub:               ");
3941   Klass* sub = subklass();
3942   int n;
3943   for (n = 0; sub != nullptr; n++, sub = sub->next_sibling()) {
3944     if (n < MaxSubklassPrintSize) {
3945       sub->print_value_on(st);
3946       st->print("   ");
3947     }
3948   }
3949   if (n >= MaxSubklassPrintSize) st->print("(%zd more klasses...)", n - MaxSubklassPrintSize);
3950   st->cr();
3951 
3952   if (is_interface()) {
3953     st->print_cr(BULLET"nof implementors:  %d", nof_implementors());
3954     if (nof_implementors() == 1) {
3955       st->print_cr(BULLET"implementor:    ");
3956       st->print("   ");
3957       implementor()->print_value_on(st);
3958       st->cr();
3959     }
3960   }
3961 
3962   st->print(BULLET"arrays:            "); Metadata::print_value_on_maybe_null(st, array_klasses()); st->cr();
3963   st->print(BULLET"methods:           "); print_array_on(st, methods());
3964   st->print(BULLET"method ordering:   "); print_array_on(st, method_ordering());
3965   if (default_methods() != nullptr) {
3966     st->print(BULLET"default_methods:   "); print_array_on(st, default_methods());
3967   }
3968   print_on_maybe_null(st, BULLET"default vtable indices:   ", default_vtable_indices());
3969   st->print(BULLET"local interfaces:  "); local_interfaces()->print_value_on(st);      st->cr();
3970   st->print(BULLET"trans. interfaces: "); transitive_interfaces()->print_value_on(st); st->cr();
3971 
3972   st->print(BULLET"secondary supers: "); secondary_supers()->print_value_on(st); st->cr();
3973 
3974   st->print(BULLET"hash_slot:         %d", hash_slot()); st->cr();
3975   st->print(BULLET"secondary bitmap: " UINTX_FORMAT_X_0, _secondary_supers_bitmap); st->cr();
3976 
3977   if (secondary_supers() != nullptr) {
3978     if (Verbose) {
3979       bool is_hashed = (_secondary_supers_bitmap != SECONDARY_SUPERS_BITMAP_FULL);
3980       st->print_cr(BULLET"---- secondary supers (%d words):", _secondary_supers->length());
3981       for (int i = 0; i < _secondary_supers->length(); i++) {
3982         ResourceMark rm; // for external_name()
3983         Klass* secondary_super = _secondary_supers->at(i);
3984         st->print(BULLET"%2d:", i);
3985         if (is_hashed) {
3986           int home_slot = compute_home_slot(secondary_super, _secondary_supers_bitmap);
3987           int distance = (i - home_slot) & SECONDARY_SUPERS_TABLE_MASK;
3988           st->print(" dist:%02d:", distance);
3989         }
3990         st->print_cr(" %p %s", secondary_super, secondary_super->external_name());
3991       }
3992     }
3993   }
3994   st->print(BULLET"constants:         "); constants()->print_value_on(st);         st->cr();
3995 
3996   print_on_maybe_null(st, BULLET"class loader data:  ", class_loader_data());
3997   print_on_maybe_null(st, BULLET"source file:       ", source_file_name());
3998   if (source_debug_extension() != nullptr) {
3999     st->print(BULLET"source debug extension:       ");
4000     st->print("%s", source_debug_extension());
4001     st->cr();
4002   }
4003   print_on_maybe_null(st, BULLET"class annotations:       ", class_annotations());
4004   print_on_maybe_null(st, BULLET"class type annotations:  ", class_type_annotations());
4005   print_on_maybe_null(st, BULLET"field annotations:       ", fields_annotations());
4006   print_on_maybe_null(st, BULLET"field type annotations:  ", fields_type_annotations());
4007   {
4008     bool have_pv = false;
4009     // previous versions are linked together through the InstanceKlass
4010     for (InstanceKlass* pv_node = previous_versions();
4011          pv_node != nullptr;
4012          pv_node = pv_node->previous_versions()) {
4013       if (!have_pv)
4014         st->print(BULLET"previous version:  ");
4015       have_pv = true;
4016       pv_node->constants()->print_value_on(st);
4017     }
4018     if (have_pv) st->cr();
4019   }
4020 
4021   print_on_maybe_null(st, BULLET"generic signature: ", generic_signature());
4022   st->print(BULLET"inner classes:     "); inner_classes()->print_value_on(st);     st->cr();
4023   st->print(BULLET"nest members:     "); nest_members()->print_value_on(st);     st->cr();
4024   print_on_maybe_null(st, BULLET"record components:     ", record_components());
4025   st->print(BULLET"permitted subclasses:     "); permitted_subclasses()->print_value_on(st);     st->cr();
4026   st->print(BULLET"loadable descriptors:     "); loadable_descriptors()->print_value_on(st); st->cr();
4027   if (java_mirror() != nullptr) {
4028     st->print(BULLET"java mirror:       ");
4029     java_mirror()->print_value_on(st);
4030     st->cr();
4031   } else {
4032     st->print_cr(BULLET"java mirror:       null");
4033   }
4034   st->print(BULLET"vtable length      %d  (start addr: " PTR_FORMAT ")", vtable_length(), p2i(start_of_vtable())); st->cr();
4035   if (vtable_length() > 0 && (Verbose || WizardMode))  print_vtable(start_of_vtable(), vtable_length(), st);
4036   st->print(BULLET"itable length      %d (start addr: " PTR_FORMAT ")", itable_length(), p2i(start_of_itable())); st->cr();
4037   if (itable_length() > 0 && (Verbose || WizardMode))  print_vtable(nullptr, start_of_itable(), itable_length(), st);
4038   st->print_cr(BULLET"---- static fields (%d words):", static_field_size());
4039 
4040   FieldPrinter print_static_field(st);
4041   ((InstanceKlass*)this)->do_local_static_fields(&print_static_field);
4042   st->print_cr(BULLET"---- non-static fields (%d words):", nonstatic_field_size());
4043   FieldPrinter print_nonstatic_field(st);
4044   InstanceKlass* ik = const_cast<InstanceKlass*>(this);
4045   ik->print_nonstatic_fields(&print_nonstatic_field);
4046 
4047   st->print(BULLET"non-static oop maps: ");
4048   OopMapBlock* map     = start_of_nonstatic_oop_maps();
4049   OopMapBlock* end_map = map + nonstatic_oop_map_count();
4050   while (map < end_map) {
4051     st->print("%d-%d ", map->offset(), map->offset() + heapOopSize*(map->count() - 1));
4052     map++;
4053   }
4054   st->cr();
4055 }
4056 
4057 void InstanceKlass::print_value_on(outputStream* st) const {
4058   assert(is_klass(), "must be klass");
4059   if (Verbose || WizardMode)  access_flags().print_on(st);
4060   name()->print_value_on(st);
4061 }
4062 
4063 void FieldPrinter::do_field(fieldDescriptor* fd) {
4064   for (int i = 0; i < _indent; i++) _st->print("  ");
4065   _st->print(BULLET);
4066    if (_obj == nullptr) {
4067      fd->print_on(_st, _base_offset);
4068      _st->cr();
4069    } else {
4070      fd->print_on_for(_st, _obj, _indent, _base_offset);
4071      if (!fd->field_flags().is_flat()) _st->cr();
4072    }
4073 }
4074 
4075 
4076 void InstanceKlass::oop_print_on(oop obj, outputStream* st, int indent, int base_offset) {
4077   Klass::oop_print_on(obj, st);
4078 
4079   if (this == vmClasses::String_klass()) {
4080     typeArrayOop value  = java_lang_String::value(obj);
4081     juint        length = java_lang_String::length(obj);
4082     if (value != nullptr &&
4083         value->is_typeArray() &&
4084         length <= (juint) value->length()) {
4085       st->print(BULLET"string: ");
4086       java_lang_String::print(obj, st);
4087       st->cr();
4088     }
4089   }
4090 
4091   st->print_cr(BULLET"---- fields (total size %zu words):", oop_size(obj));
4092   FieldPrinter print_field(st, obj, indent, base_offset);
4093   print_nonstatic_fields(&print_field);
4094 
4095   if (this == vmClasses::Class_klass()) {
4096     st->print(BULLET"signature: ");
4097     java_lang_Class::print_signature(obj, st);
4098     st->cr();
4099     Klass* real_klass = java_lang_Class::as_Klass(obj);
4100     if (real_klass != nullptr && real_klass->is_instance_klass()) {
4101       st->print_cr(BULLET"---- static fields (%d):", java_lang_Class::static_oop_field_count(obj));
4102       InstanceKlass::cast(real_klass)->do_local_static_fields(&print_field);
4103     }
4104   } else if (this == vmClasses::MethodType_klass()) {
4105     st->print(BULLET"signature: ");
4106     java_lang_invoke_MethodType::print_signature(obj, st);
4107     st->cr();
4108   }
4109 }
4110 
4111 #ifndef PRODUCT
4112 
4113 bool InstanceKlass::verify_itable_index(int i) {
4114   int method_count = klassItable::method_count_for_interface(this);
4115   assert(i >= 0 && i < method_count, "index out of bounds");
4116   return true;
4117 }
4118 
4119 #endif //PRODUCT
4120 
4121 void InstanceKlass::oop_print_value_on(oop obj, outputStream* st) {
4122   st->print("a ");
4123   name()->print_value_on(st);
4124   obj->print_address_on(st);
4125   if (this == vmClasses::String_klass()
4126       && java_lang_String::value(obj) != nullptr) {
4127     ResourceMark rm;
4128     int len = java_lang_String::length(obj);
4129     int plen = (len < 24 ? len : 12);
4130     char* str = java_lang_String::as_utf8_string(obj, 0, plen);
4131     st->print(" = \"%s\"", str);
4132     if (len > plen)
4133       st->print("...[%d]", len);
4134   } else if (this == vmClasses::Class_klass()) {
4135     Klass* k = java_lang_Class::as_Klass(obj);
4136     st->print(" = ");
4137     if (k != nullptr) {
4138       k->print_value_on(st);
4139     } else {
4140       const char* tname = type2name(java_lang_Class::primitive_type(obj));
4141       st->print("%s", tname ? tname : "type?");
4142     }
4143   } else if (this == vmClasses::MethodType_klass()) {
4144     st->print(" = ");
4145     java_lang_invoke_MethodType::print_signature(obj, st);
4146   } else if (java_lang_boxing_object::is_instance(obj)) {
4147     st->print(" = ");
4148     java_lang_boxing_object::print(obj, st);
4149   } else if (this == vmClasses::LambdaForm_klass()) {
4150     oop vmentry = java_lang_invoke_LambdaForm::vmentry(obj);
4151     if (vmentry != nullptr) {
4152       st->print(" => ");
4153       vmentry->print_value_on(st);
4154     }
4155   } else if (this == vmClasses::MemberName_klass()) {
4156     Metadata* vmtarget = java_lang_invoke_MemberName::vmtarget(obj);
4157     if (vmtarget != nullptr) {
4158       st->print(" = ");
4159       vmtarget->print_value_on(st);
4160     } else {
4161       oop clazz = java_lang_invoke_MemberName::clazz(obj);
4162       oop name  = java_lang_invoke_MemberName::name(obj);
4163       if (clazz != nullptr) {
4164         clazz->print_value_on(st);
4165       } else {
4166         st->print("null");
4167       }
4168       st->print(".");
4169       if (name != nullptr) {
4170         name->print_value_on(st);
4171       } else {
4172         st->print("null");
4173       }
4174     }
4175   }
4176 }
4177 
4178 const char* InstanceKlass::internal_name() const {
4179   return external_name();
4180 }
4181 
4182 void InstanceKlass::print_class_load_logging(ClassLoaderData* loader_data,
4183                                              const ModuleEntry* module_entry,
4184                                              const ClassFileStream* cfs) const {
4185 
4186   if (ClassListWriter::is_enabled()) {
4187     ClassListWriter::write(this, cfs);
4188   }
4189 
4190   print_class_load_helper(loader_data, module_entry, cfs);
4191   print_class_load_cause_logging();
4192 }
4193 
4194 void InstanceKlass::print_class_load_helper(ClassLoaderData* loader_data,
4195                                              const ModuleEntry* module_entry,
4196                                              const ClassFileStream* cfs) const {
4197 
4198   if (!log_is_enabled(Info, class, load)) {
4199     return;
4200   }
4201 
4202   ResourceMark rm;
4203   LogMessage(class, load) msg;
4204   stringStream info_stream;
4205 
4206   // Name and class hierarchy info
4207   info_stream.print("%s", external_name());
4208 
4209   // Source
4210   if (cfs != nullptr) {
4211     if (cfs->source() != nullptr) {
4212       const char* module_name = (module_entry->name() == nullptr) ? UNNAMED_MODULE : module_entry->name()->as_C_string();
4213       if (module_name != nullptr) {
4214         // When the boot loader created the stream, it didn't know the module name
4215         // yet. Let's format it now.
4216         if (cfs->from_boot_loader_modules_image()) {
4217           info_stream.print(" source: jrt:/%s", module_name);
4218         } else {
4219           info_stream.print(" source: %s", cfs->source());
4220         }
4221       } else {
4222         info_stream.print(" source: %s", cfs->source());
4223       }
4224     } else if (loader_data == ClassLoaderData::the_null_class_loader_data()) {
4225       Thread* current = Thread::current();
4226       Klass* caller = current->is_Java_thread() ?
4227         JavaThread::cast(current)->security_get_caller_class(1):
4228         nullptr;
4229       // caller can be null, for example, during a JVMTI VM_Init hook
4230       if (caller != nullptr) {
4231         info_stream.print(" source: instance of %s", caller->external_name());
4232       } else {
4233         // source is unknown
4234       }
4235     } else {
4236       oop class_loader = loader_data->class_loader();
4237       info_stream.print(" source: %s", class_loader->klass()->external_name());
4238     }
4239   } else {
4240     assert(this->is_shared(), "must be");
4241     if (MetaspaceShared::is_shared_dynamic((void*)this)) {
4242       info_stream.print(" source: shared objects file (top)");
4243     } else {
4244       info_stream.print(" source: shared objects file");
4245     }
4246   }
4247 
4248   msg.info("%s", info_stream.as_string());
4249 
4250   if (log_is_enabled(Debug, class, load)) {
4251     stringStream debug_stream;
4252 
4253     // Class hierarchy info
4254     debug_stream.print(" klass: " PTR_FORMAT " super: " PTR_FORMAT,
4255                        p2i(this),  p2i(superklass()));
4256 
4257     // Interfaces
4258     if (local_interfaces() != nullptr && local_interfaces()->length() > 0) {
4259       debug_stream.print(" interfaces:");
4260       int length = local_interfaces()->length();
4261       for (int i = 0; i < length; i++) {
4262         debug_stream.print(" " PTR_FORMAT,
4263                            p2i(InstanceKlass::cast(local_interfaces()->at(i))));
4264       }
4265     }
4266 
4267     // Class loader
4268     debug_stream.print(" loader: [");
4269     loader_data->print_value_on(&debug_stream);
4270     debug_stream.print("]");
4271 
4272     // Classfile checksum
4273     if (cfs) {
4274       debug_stream.print(" bytes: %d checksum: %08x",
4275                          cfs->length(),
4276                          ClassLoader::crc32(0, (const char*)cfs->buffer(),
4277                          cfs->length()));
4278     }
4279 
4280     msg.debug("%s", debug_stream.as_string());
4281   }
4282 }
4283 
4284 void InstanceKlass::print_class_load_cause_logging() const {
4285   bool log_cause_native = log_is_enabled(Info, class, load, cause, native);
4286   if (log_cause_native || log_is_enabled(Info, class, load, cause)) {
4287     JavaThread* current = JavaThread::current();
4288     ResourceMark rm(current);
4289     const char* name = external_name();
4290 
4291     if (LogClassLoadingCauseFor == nullptr ||
4292         (strcmp("*", LogClassLoadingCauseFor) != 0 &&
4293          strstr(name, LogClassLoadingCauseFor) == nullptr)) {
4294         return;
4295     }
4296 
4297     // Log Java stack first
4298     {
4299       LogMessage(class, load, cause) msg;
4300       NonInterleavingLogStream info_stream{LogLevelType::Info, msg};
4301 
4302       info_stream.print_cr("Java stack when loading %s:", name);
4303       current->print_stack_on(&info_stream);
4304     }
4305 
4306     // Log native stack second
4307     if (log_cause_native) {
4308       // Log to string first so that lines can be indented
4309       stringStream stack_stream;
4310       char buf[O_BUFLEN];
4311       address lastpc = nullptr;
4312       NativeStackPrinter nsp(current);
4313       nsp.print_stack(&stack_stream, buf, sizeof(buf), lastpc,
4314                       true /* print_source_info */, -1 /* max stack */);
4315 
4316       LogMessage(class, load, cause, native) msg;
4317       NonInterleavingLogStream info_stream{LogLevelType::Info, msg};
4318       info_stream.print_cr("Native stack when loading %s:", name);
4319 
4320       // Print each native stack line to the log
4321       int size = (int) stack_stream.size();
4322       char* stack = stack_stream.as_string();
4323       char* stack_end = stack + size;
4324       char* line_start = stack;
4325       for (char* p = stack; p < stack_end; p++) {
4326         if (*p == '\n') {
4327           *p = '\0';
4328           info_stream.print_cr("\t%s", line_start);
4329           line_start = p + 1;
4330         }
4331       }
4332       if (line_start < stack_end) {
4333         info_stream.print_cr("\t%s", line_start);
4334       }
4335     }
4336   }
4337 }
4338 
4339 // Verification
4340 
4341 class VerifyFieldClosure: public BasicOopIterateClosure {
4342  protected:
4343   template <class T> void do_oop_work(T* p) {
4344     oop obj = RawAccess<>::oop_load(p);
4345     if (!oopDesc::is_oop_or_null(obj)) {
4346       tty->print_cr("Failed: " PTR_FORMAT " -> " PTR_FORMAT, p2i(p), p2i(obj));
4347       Universe::print_on(tty);
4348       guarantee(false, "boom");
4349     }
4350   }
4351  public:
4352   virtual void do_oop(oop* p)       { VerifyFieldClosure::do_oop_work(p); }
4353   virtual void do_oop(narrowOop* p) { VerifyFieldClosure::do_oop_work(p); }
4354 };
4355 
4356 void InstanceKlass::verify_on(outputStream* st) {
4357 #ifndef PRODUCT
4358   // Avoid redundant verifies, this really should be in product.
4359   if (_verify_count == Universe::verify_count()) return;
4360   _verify_count = Universe::verify_count();
4361 #endif
4362 
4363   // Verify Klass
4364   Klass::verify_on(st);
4365 
4366   // Verify that klass is present in ClassLoaderData
4367   guarantee(class_loader_data()->contains_klass(this),
4368             "this class isn't found in class loader data");
4369 
4370   // Verify vtables
4371   if (is_linked()) {
4372     // $$$ This used to be done only for m/s collections.  Doing it
4373     // always seemed a valid generalization.  (DLD -- 6/00)
4374     vtable().verify(st);
4375   }
4376 
4377   // Verify first subklass
4378   if (subklass() != nullptr) {
4379     guarantee(subklass()->is_klass(), "should be klass");
4380   }
4381 
4382   // Verify siblings
4383   Klass* super = this->super();
4384   Klass* sib = next_sibling();
4385   if (sib != nullptr) {
4386     if (sib == this) {
4387       fatal("subclass points to itself " PTR_FORMAT, p2i(sib));
4388     }
4389 
4390     guarantee(sib->is_klass(), "should be klass");
4391     guarantee(sib->super() == super, "siblings should have same superklass");
4392   }
4393 
4394   // Verify local interfaces
4395   if (local_interfaces()) {
4396     Array<InstanceKlass*>* local_interfaces = this->local_interfaces();
4397     for (int j = 0; j < local_interfaces->length(); j++) {
4398       InstanceKlass* e = local_interfaces->at(j);
4399       guarantee(e->is_klass() && e->is_interface(), "invalid local interface");
4400     }
4401   }
4402 
4403   // Verify transitive interfaces
4404   if (transitive_interfaces() != nullptr) {
4405     Array<InstanceKlass*>* transitive_interfaces = this->transitive_interfaces();
4406     for (int j = 0; j < transitive_interfaces->length(); j++) {
4407       InstanceKlass* e = transitive_interfaces->at(j);
4408       guarantee(e->is_klass() && e->is_interface(), "invalid transitive interface");
4409     }
4410   }
4411 
4412   // Verify methods
4413   if (methods() != nullptr) {
4414     Array<Method*>* methods = this->methods();
4415     for (int j = 0; j < methods->length(); j++) {
4416       guarantee(methods->at(j)->is_method(), "non-method in methods array");
4417     }
4418     for (int j = 0; j < methods->length() - 1; j++) {
4419       Method* m1 = methods->at(j);
4420       Method* m2 = methods->at(j + 1);
4421       guarantee(m1->name()->fast_compare(m2->name()) <= 0, "methods not sorted correctly");
4422     }
4423   }
4424 
4425   // Verify method ordering
4426   if (method_ordering() != nullptr) {
4427     Array<int>* method_ordering = this->method_ordering();
4428     int length = method_ordering->length();
4429     if (JvmtiExport::can_maintain_original_method_order() ||
4430         ((CDSConfig::is_using_archive() || CDSConfig::is_dumping_archive()) && length != 0)) {
4431       guarantee(length == methods()->length(), "invalid method ordering length");
4432       jlong sum = 0;
4433       for (int j = 0; j < length; j++) {
4434         int original_index = method_ordering->at(j);
4435         guarantee(original_index >= 0, "invalid method ordering index");
4436         guarantee(original_index < length, "invalid method ordering index");
4437         sum += original_index;
4438       }
4439       // Verify sum of indices 0,1,...,length-1
4440       guarantee(sum == ((jlong)length*(length-1))/2, "invalid method ordering sum");
4441     } else {
4442       guarantee(length == 0, "invalid method ordering length");
4443     }
4444   }
4445 
4446   // Verify default methods
4447   if (default_methods() != nullptr) {
4448     Array<Method*>* methods = this->default_methods();
4449     for (int j = 0; j < methods->length(); j++) {
4450       guarantee(methods->at(j)->is_method(), "non-method in methods array");
4451     }
4452     for (int j = 0; j < methods->length() - 1; j++) {
4453       Method* m1 = methods->at(j);
4454       Method* m2 = methods->at(j + 1);
4455       guarantee(m1->name()->fast_compare(m2->name()) <= 0, "methods not sorted correctly");
4456     }
4457   }
4458 
4459   // Verify JNI static field identifiers
4460   if (jni_ids() != nullptr) {
4461     jni_ids()->verify(this);
4462   }
4463 
4464   // Verify other fields
4465   if (constants() != nullptr) {
4466     guarantee(constants()->is_constantPool(), "should be constant pool");
4467   }
4468 }
4469 
4470 void InstanceKlass::oop_verify_on(oop obj, outputStream* st) {
4471   Klass::oop_verify_on(obj, st);
4472   VerifyFieldClosure blk;
4473   obj->oop_iterate(&blk);
4474 }
4475 
4476 
4477 // JNIid class for jfieldIDs only
4478 // Note to reviewers:
4479 // These JNI functions are just moved over to column 1 and not changed
4480 // in the compressed oops workspace.
4481 JNIid::JNIid(Klass* holder, int offset, JNIid* next) {
4482   _holder = holder;
4483   _offset = offset;
4484   _next = next;
4485   debug_only(_is_static_field_id = false;)
4486 }
4487 
4488 
4489 JNIid* JNIid::find(int offset) {
4490   JNIid* current = this;
4491   while (current != nullptr) {
4492     if (current->offset() == offset) return current;
4493     current = current->next();
4494   }
4495   return nullptr;
4496 }
4497 
4498 void JNIid::deallocate(JNIid* current) {
4499   while (current != nullptr) {
4500     JNIid* next = current->next();
4501     delete current;
4502     current = next;
4503   }
4504 }
4505 
4506 
4507 void JNIid::verify(Klass* holder) {
4508   int first_field_offset  = InstanceMirrorKlass::offset_of_static_fields();
4509   int end_field_offset;
4510   end_field_offset = first_field_offset + (InstanceKlass::cast(holder)->static_field_size() * wordSize);
4511 
4512   JNIid* current = this;
4513   while (current != nullptr) {
4514     guarantee(current->holder() == holder, "Invalid klass in JNIid");
4515 #ifdef ASSERT
4516     int o = current->offset();
4517     if (current->is_static_field_id()) {
4518       guarantee(o >= first_field_offset  && o < end_field_offset,  "Invalid static field offset in JNIid");
4519     }
4520 #endif
4521     current = current->next();
4522   }
4523 }
4524 
4525 void InstanceKlass::set_init_state(ClassState state) {
4526 #ifdef ASSERT
4527   bool good_state = is_shared() ? (_init_state <= state)
4528                                                : (_init_state < state);
4529   assert(good_state || state == allocated, "illegal state transition");
4530 #endif
4531   assert(_init_thread == nullptr, "should be cleared before state change");
4532   Atomic::release_store(&_init_state, state);
4533 }
4534 
4535 #if INCLUDE_JVMTI
4536 
4537 // RedefineClasses() support for previous versions
4538 
4539 // Globally, there is at least one previous version of a class to walk
4540 // during class unloading, which is saved because old methods in the class
4541 // are still running.   Otherwise the previous version list is cleaned up.
4542 bool InstanceKlass::_should_clean_previous_versions = false;
4543 
4544 // Returns true if there are previous versions of a class for class
4545 // unloading only. Also resets the flag to false. purge_previous_version
4546 // will set the flag to true if there are any left, i.e., if there's any
4547 // work to do for next time. This is to avoid the expensive code cache
4548 // walk in CLDG::clean_deallocate_lists().
4549 bool InstanceKlass::should_clean_previous_versions_and_reset() {
4550   bool ret = _should_clean_previous_versions;
4551   log_trace(redefine, class, iklass, purge)("Class unloading: should_clean_previous_versions = %s",
4552      ret ? "true" : "false");
4553   _should_clean_previous_versions = false;
4554   return ret;
4555 }
4556 
4557 // This nulls out jmethodIDs for all methods in 'klass'
4558 // It needs to be called explicitly for all previous versions of a class because these may not be cleaned up
4559 // during class unloading.
4560 // We can not use the jmethodID cache associated with klass directly because the 'previous' versions
4561 // do not have the jmethodID cache filled in. Instead, we need to lookup jmethodID for each method and this
4562 // is expensive - O(n) for one jmethodID lookup. For all contained methods it is O(n^2).
4563 // The reason for expensive jmethodID lookup for each method is that there is no direct link between method and jmethodID.
4564 void InstanceKlass::clear_jmethod_ids(InstanceKlass* klass) {
4565   Array<Method*>* method_refs = klass->methods();
4566   for (int k = 0; k < method_refs->length(); k++) {
4567     Method* method = method_refs->at(k);
4568     if (method != nullptr && method->is_obsolete()) {
4569       method->clear_jmethod_id();
4570     }
4571   }
4572 }
4573 
4574 // Purge previous versions before adding new previous versions of the class and
4575 // during class unloading.
4576 void InstanceKlass::purge_previous_version_list() {
4577   assert(SafepointSynchronize::is_at_safepoint(), "only called at safepoint");
4578   assert(has_been_redefined(), "Should only be called for main class");
4579 
4580   // Quick exit.
4581   if (previous_versions() == nullptr) {
4582     return;
4583   }
4584 
4585   // This klass has previous versions so see what we can cleanup
4586   // while it is safe to do so.
4587 
4588   int deleted_count = 0;    // leave debugging breadcrumbs
4589   int live_count = 0;
4590   ClassLoaderData* loader_data = class_loader_data();
4591   assert(loader_data != nullptr, "should never be null");
4592 
4593   ResourceMark rm;
4594   log_trace(redefine, class, iklass, purge)("%s: previous versions", external_name());
4595 
4596   // previous versions are linked together through the InstanceKlass
4597   InstanceKlass* pv_node = previous_versions();
4598   InstanceKlass* last = this;
4599   int version = 0;
4600 
4601   // check the previous versions list
4602   for (; pv_node != nullptr; ) {
4603 
4604     ConstantPool* pvcp = pv_node->constants();
4605     assert(pvcp != nullptr, "cp ref was unexpectedly cleared");
4606 
4607     if (!pvcp->on_stack()) {
4608       // If the constant pool isn't on stack, none of the methods
4609       // are executing.  Unlink this previous_version.
4610       // The previous version InstanceKlass is on the ClassLoaderData deallocate list
4611       // so will be deallocated during the next phase of class unloading.
4612       log_trace(redefine, class, iklass, purge)
4613         ("previous version " PTR_FORMAT " is dead.", p2i(pv_node));
4614       // Unlink from previous version list.
4615       assert(pv_node->class_loader_data() == loader_data, "wrong loader_data");
4616       InstanceKlass* next = pv_node->previous_versions();
4617       clear_jmethod_ids(pv_node); // jmethodID maintenance for the unloaded class
4618       pv_node->link_previous_versions(nullptr);   // point next to null
4619       last->link_previous_versions(next);
4620       // Delete this node directly. Nothing is referring to it and we don't
4621       // want it to increase the counter for metadata to delete in CLDG.
4622       MetadataFactory::free_metadata(loader_data, pv_node);
4623       pv_node = next;
4624       deleted_count++;
4625       version++;
4626       continue;
4627     } else {
4628       assert(pvcp->pool_holder() != nullptr, "Constant pool with no holder");
4629       guarantee (!loader_data->is_unloading(), "unloaded classes can't be on the stack");
4630       live_count++;
4631       if (pvcp->is_shared()) {
4632         // Shared previous versions can never be removed so no cleaning is needed.
4633         log_trace(redefine, class, iklass, purge)("previous version " PTR_FORMAT " is shared", p2i(pv_node));
4634       } else {
4635         // Previous version alive, set that clean is needed for next time.
4636         _should_clean_previous_versions = true;
4637         log_trace(redefine, class, iklass, purge)("previous version " PTR_FORMAT " is alive", p2i(pv_node));
4638       }
4639     }
4640 
4641     // next previous version
4642     last = pv_node;
4643     pv_node = pv_node->previous_versions();
4644     version++;
4645   }
4646   log_trace(redefine, class, iklass, purge)
4647     ("previous version stats: live=%d, deleted=%d", live_count, deleted_count);
4648 }
4649 
4650 void InstanceKlass::mark_newly_obsolete_methods(Array<Method*>* old_methods,
4651                                                 int emcp_method_count) {
4652   int obsolete_method_count = old_methods->length() - emcp_method_count;
4653 
4654   if (emcp_method_count != 0 && obsolete_method_count != 0 &&
4655       _previous_versions != nullptr) {
4656     // We have a mix of obsolete and EMCP methods so we have to
4657     // clear out any matching EMCP method entries the hard way.
4658     int local_count = 0;
4659     for (int i = 0; i < old_methods->length(); i++) {
4660       Method* old_method = old_methods->at(i);
4661       if (old_method->is_obsolete()) {
4662         // only obsolete methods are interesting
4663         Symbol* m_name = old_method->name();
4664         Symbol* m_signature = old_method->signature();
4665 
4666         // previous versions are linked together through the InstanceKlass
4667         int j = 0;
4668         for (InstanceKlass* prev_version = _previous_versions;
4669              prev_version != nullptr;
4670              prev_version = prev_version->previous_versions(), j++) {
4671 
4672           Array<Method*>* method_refs = prev_version->methods();
4673           for (int k = 0; k < method_refs->length(); k++) {
4674             Method* method = method_refs->at(k);
4675 
4676             if (!method->is_obsolete() &&
4677                 method->name() == m_name &&
4678                 method->signature() == m_signature) {
4679               // The current RedefineClasses() call has made all EMCP
4680               // versions of this method obsolete so mark it as obsolete
4681               log_trace(redefine, class, iklass, add)
4682                 ("%s(%s): flush obsolete method @%d in version @%d",
4683                  m_name->as_C_string(), m_signature->as_C_string(), k, j);
4684 
4685               method->set_is_obsolete();
4686               break;
4687             }
4688           }
4689 
4690           // The previous loop may not find a matching EMCP method, but
4691           // that doesn't mean that we can optimize and not go any
4692           // further back in the PreviousVersion generations. The EMCP
4693           // method for this generation could have already been made obsolete,
4694           // but there still may be an older EMCP method that has not
4695           // been made obsolete.
4696         }
4697 
4698         if (++local_count >= obsolete_method_count) {
4699           // no more obsolete methods so bail out now
4700           break;
4701         }
4702       }
4703     }
4704   }
4705 }
4706 
4707 // Save the scratch_class as the previous version if any of the methods are running.
4708 // The previous_versions are used to set breakpoints in EMCP methods and they are
4709 // also used to clean MethodData links to redefined methods that are no longer running.
4710 void InstanceKlass::add_previous_version(InstanceKlass* scratch_class,
4711                                          int emcp_method_count) {
4712   assert(Thread::current()->is_VM_thread(),
4713          "only VMThread can add previous versions");
4714 
4715   ResourceMark rm;
4716   log_trace(redefine, class, iklass, add)
4717     ("adding previous version ref for %s, EMCP_cnt=%d", scratch_class->external_name(), emcp_method_count);
4718 
4719   // Clean out old previous versions for this class
4720   purge_previous_version_list();
4721 
4722   // Mark newly obsolete methods in remaining previous versions.  An EMCP method from
4723   // a previous redefinition may be made obsolete by this redefinition.
4724   Array<Method*>* old_methods = scratch_class->methods();
4725   mark_newly_obsolete_methods(old_methods, emcp_method_count);
4726 
4727   // If the constant pool for this previous version of the class
4728   // is not marked as being on the stack, then none of the methods
4729   // in this previous version of the class are on the stack so
4730   // we don't need to add this as a previous version.
4731   ConstantPool* cp_ref = scratch_class->constants();
4732   if (!cp_ref->on_stack()) {
4733     log_trace(redefine, class, iklass, add)("scratch class not added; no methods are running");
4734     scratch_class->class_loader_data()->add_to_deallocate_list(scratch_class);
4735     return;
4736   }
4737 
4738   // Add previous version if any methods are still running or if this is
4739   // a shared class which should never be removed.
4740   assert(scratch_class->previous_versions() == nullptr, "shouldn't have a previous version");
4741   scratch_class->link_previous_versions(previous_versions());
4742   link_previous_versions(scratch_class);
4743   if (cp_ref->is_shared()) {
4744     log_trace(redefine, class, iklass, add) ("scratch class added; class is shared");
4745   } else {
4746     //  We only set clean_previous_versions flag for processing during class
4747     // unloading for non-shared classes.
4748     _should_clean_previous_versions = true;
4749     log_trace(redefine, class, iklass, add) ("scratch class added; one of its methods is on_stack.");
4750   }
4751 } // end add_previous_version()
4752 
4753 #endif // INCLUDE_JVMTI
4754 
4755 Method* InstanceKlass::method_with_idnum(int idnum) {
4756   Method* m = nullptr;
4757   if (idnum < methods()->length()) {
4758     m = methods()->at(idnum);
4759   }
4760   if (m == nullptr || m->method_idnum() != idnum) {
4761     for (int index = 0; index < methods()->length(); ++index) {
4762       m = methods()->at(index);
4763       if (m->method_idnum() == idnum) {
4764         return m;
4765       }
4766     }
4767     // None found, return null for the caller to handle.
4768     return nullptr;
4769   }
4770   return m;
4771 }
4772 
4773 
4774 Method* InstanceKlass::method_with_orig_idnum(int idnum) {
4775   if (idnum >= methods()->length()) {
4776     return nullptr;
4777   }
4778   Method* m = methods()->at(idnum);
4779   if (m != nullptr && m->orig_method_idnum() == idnum) {
4780     return m;
4781   }
4782   // Obsolete method idnum does not match the original idnum
4783   for (int index = 0; index < methods()->length(); ++index) {
4784     m = methods()->at(index);
4785     if (m->orig_method_idnum() == idnum) {
4786       return m;
4787     }
4788   }
4789   // None found, return null for the caller to handle.
4790   return nullptr;
4791 }
4792 
4793 
4794 Method* InstanceKlass::method_with_orig_idnum(int idnum, int version) {
4795   InstanceKlass* holder = get_klass_version(version);
4796   if (holder == nullptr) {
4797     return nullptr; // The version of klass is gone, no method is found
4798   }
4799   Method* method = holder->method_with_orig_idnum(idnum);
4800   return method;
4801 }
4802 
4803 #if INCLUDE_JVMTI
4804 JvmtiCachedClassFileData* InstanceKlass::get_cached_class_file() {
4805   return _cached_class_file;
4806 }
4807 
4808 jint InstanceKlass::get_cached_class_file_len() {
4809   return VM_RedefineClasses::get_cached_class_file_len(_cached_class_file);
4810 }
4811 
4812 unsigned char * InstanceKlass::get_cached_class_file_bytes() {
4813   return VM_RedefineClasses::get_cached_class_file_bytes(_cached_class_file);
4814 }
4815 #endif
4816 
4817 // Make a step iterating over the class hierarchy under the root class.
4818 // Skips subclasses if requested.
4819 void ClassHierarchyIterator::next() {
4820   assert(_current != nullptr, "required");
4821   if (_visit_subclasses && _current->subklass() != nullptr) {
4822     _current = _current->subklass();
4823     return; // visit next subclass
4824   }
4825   _visit_subclasses = true; // reset
4826   while (_current->next_sibling() == nullptr && _current != _root) {
4827     _current = _current->superklass(); // backtrack; no more sibling subclasses left
4828   }
4829   if (_current == _root) {
4830     // Iteration is over (back at root after backtracking). Invalidate the iterator.
4831     _current = nullptr;
4832     return;
4833   }
4834   _current = _current->next_sibling();
4835   return; // visit next sibling subclass
4836 }