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