1 /*
   2  * Copyright (c) 1997, 2017, 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 "precompiled.hpp"
  26 #include "aot/aotLoader.hpp"
  27 #include "classfile/classFileParser.hpp"
  28 #include "classfile/classFileStream.hpp"
  29 #include "classfile/classLoader.hpp"
  30 #include "classfile/javaClasses.hpp"
  31 #include "classfile/moduleEntry.hpp"
  32 #include "classfile/systemDictionary.hpp"
  33 #include "classfile/systemDictionaryShared.hpp"
  34 #include "classfile/verifier.hpp"
  35 #include "classfile/vmSymbols.hpp"
  36 #include "code/dependencyContext.hpp"
  37 #include "compiler/compileBroker.hpp"
  38 #include "gc/shared/collectedHeap.inline.hpp"
  39 #include "gc/shared/specialized_oop_closures.hpp"
  40 #include "interpreter/oopMapCache.hpp"
  41 #include "interpreter/rewriter.hpp"
  42 #include "jvmtifiles/jvmti.h"
  43 #include "logging/log.hpp"
  44 #include "memory/heapInspection.hpp"
  45 #include "memory/iterator.inline.hpp"
  46 #include "memory/metadataFactory.hpp"
  47 #include "memory/metaspaceShared.hpp"
  48 #include "memory/oopFactory.hpp"
  49 #include "memory/resourceArea.hpp"
  50 #include "oops/fieldStreams.hpp"
  51 #include "oops/instanceClassLoaderKlass.hpp"
  52 #include "oops/instanceKlass.inline.hpp"
  53 #include "oops/instanceMirrorKlass.hpp"
  54 #include "oops/instanceOop.hpp"
  55 #include "oops/klass.inline.hpp"
  56 #include "oops/method.hpp"
  57 #include "oops/oop.inline.hpp"
  58 #include "oops/symbol.hpp"
  59 #include "prims/jvmtiExport.hpp"
  60 #include "prims/jvmtiRedefineClasses.hpp"
  61 #include "prims/jvmtiThreadState.hpp"
  62 #include "prims/methodComparator.hpp"
  63 #include "runtime/atomic.hpp"
  64 #include "runtime/fieldDescriptor.hpp"
  65 #include "runtime/handles.inline.hpp"
  66 #include "runtime/javaCalls.hpp"
  67 #include "runtime/mutexLocker.hpp"
  68 #include "runtime/orderAccess.inline.hpp"
  69 #include "runtime/thread.inline.hpp"
  70 #include "services/classLoadingService.hpp"
  71 #include "services/threadService.hpp"
  72 #include "utilities/dtrace.hpp"
  73 #include "utilities/macros.hpp"
  74 #include "utilities/stringUtils.hpp"
  75 #include "logging/log.hpp"
  76 #ifdef COMPILER1
  77 #include "c1/c1_Compiler.hpp"
  78 #endif
  79 
  80 #ifdef DTRACE_ENABLED
  81 
  82 
  83 #define HOTSPOT_CLASS_INITIALIZATION_required HOTSPOT_CLASS_INITIALIZATION_REQUIRED
  84 #define HOTSPOT_CLASS_INITIALIZATION_recursive HOTSPOT_CLASS_INITIALIZATION_RECURSIVE
  85 #define HOTSPOT_CLASS_INITIALIZATION_concurrent HOTSPOT_CLASS_INITIALIZATION_CONCURRENT
  86 #define HOTSPOT_CLASS_INITIALIZATION_erroneous HOTSPOT_CLASS_INITIALIZATION_ERRONEOUS
  87 #define HOTSPOT_CLASS_INITIALIZATION_super__failed HOTSPOT_CLASS_INITIALIZATION_SUPER_FAILED
  88 #define HOTSPOT_CLASS_INITIALIZATION_clinit HOTSPOT_CLASS_INITIALIZATION_CLINIT
  89 #define HOTSPOT_CLASS_INITIALIZATION_error HOTSPOT_CLASS_INITIALIZATION_ERROR
  90 #define HOTSPOT_CLASS_INITIALIZATION_end HOTSPOT_CLASS_INITIALIZATION_END
  91 #define DTRACE_CLASSINIT_PROBE(type, thread_type)                \
  92   {                                                              \
  93     char* data = NULL;                                           \
  94     int len = 0;                                                 \
  95     Symbol* clss_name = name();                                  \
  96     if (clss_name != NULL) {                                     \
  97       data = (char*)clss_name->bytes();                          \
  98       len = clss_name->utf8_length();                            \
  99     }                                                            \
 100     HOTSPOT_CLASS_INITIALIZATION_##type(                         \
 101       data, len, class_loader(), thread_type);                   \
 102   }
 103 
 104 #define DTRACE_CLASSINIT_PROBE_WAIT(type, thread_type, wait)     \
 105   {                                                              \
 106     char* data = NULL;                                           \
 107     int len = 0;                                                 \
 108     Symbol* clss_name = name();                                  \
 109     if (clss_name != NULL) {                                     \
 110       data = (char*)clss_name->bytes();                          \
 111       len = clss_name->utf8_length();                            \
 112     }                                                            \
 113     HOTSPOT_CLASS_INITIALIZATION_##type(                         \
 114       data, len, class_loader(), thread_type, wait);             \
 115   }
 116 
 117 #else //  ndef DTRACE_ENABLED
 118 
 119 #define DTRACE_CLASSINIT_PROBE(type, thread_type)
 120 #define DTRACE_CLASSINIT_PROBE_WAIT(type, thread_type, wait)
 121 
 122 #endif //  ndef DTRACE_ENABLED
 123 
 124 volatile int InstanceKlass::_total_instanceKlass_count = 0;
 125 
 126 static inline bool is_class_loader(const Symbol* class_name,
 127                                    const ClassFileParser& parser) {
 128   assert(class_name != NULL, "invariant");
 129 
 130   if (class_name == vmSymbols::java_lang_ClassLoader()) {
 131     return true;
 132   }
 133 
 134   if (SystemDictionary::ClassLoader_klass_loaded()) {
 135     const Klass* const super_klass = parser.super_klass();
 136     if (super_klass != NULL) {
 137       if (super_klass->is_subtype_of(SystemDictionary::ClassLoader_klass())) {
 138         return true;
 139       }
 140     }
 141   }
 142   return false;
 143 }
 144 
 145 InstanceKlass* InstanceKlass::allocate_instance_klass(const ClassFileParser& parser, TRAPS) {
 146   const int size = InstanceKlass::size(parser.vtable_size(),
 147                                        parser.itable_size(),
 148                                        nonstatic_oop_map_size(parser.total_oop_map_count()),
 149                                        parser.is_interface(),
 150                                        parser.is_anonymous(),
 151                                        should_store_fingerprint());
 152 
 153   const Symbol* const class_name = parser.class_name();
 154   assert(class_name != NULL, "invariant");
 155   ClassLoaderData* loader_data = parser.loader_data();
 156   assert(loader_data != NULL, "invariant");
 157 
 158   InstanceKlass* ik;
 159 
 160   // Allocation
 161   if (REF_NONE == parser.reference_type()) {
 162     if (class_name == vmSymbols::java_lang_Class()) {
 163       // mirror
 164       ik = new (loader_data, size, THREAD) InstanceMirrorKlass(parser);
 165     }
 166     else if (is_class_loader(class_name, parser)) {
 167       // class loader
 168       ik = new (loader_data, size, THREAD) InstanceClassLoaderKlass(parser);
 169     }
 170     else {
 171       // normal
 172       ik = new (loader_data, size, THREAD) InstanceKlass(parser, InstanceKlass::_misc_kind_other);
 173     }
 174   }
 175   else {
 176     // reference
 177     ik = new (loader_data, size, THREAD) InstanceRefKlass(parser);
 178   }
 179 
 180   // Check for pending exception before adding to the loader data and incrementing
 181   // class count.  Can get OOM here.
 182   if (HAS_PENDING_EXCEPTION) {
 183     return NULL;
 184   }
 185 
 186   assert(ik != NULL, "invariant");
 187 
 188   const bool publicize = !parser.is_internal();
 189 
 190   // Add all classes to our internal class loader list here,
 191   // including classes in the bootstrap (NULL) class loader.
 192   loader_data->add_class(ik, publicize);
 193   Atomic::inc(&_total_instanceKlass_count);
 194 
 195   return ik;
 196 }
 197 
 198 
 199 // copy method ordering from resource area to Metaspace
 200 void InstanceKlass::copy_method_ordering(const intArray* m, TRAPS) {
 201   if (m != NULL) {
 202     // allocate a new array and copy contents (memcpy?)
 203     _method_ordering = MetadataFactory::new_array<int>(class_loader_data(), m->length(), CHECK);
 204     for (int i = 0; i < m->length(); i++) {
 205       _method_ordering->at_put(i, m->at(i));
 206     }
 207   } else {
 208     _method_ordering = Universe::the_empty_int_array();
 209   }
 210 }
 211 
 212 // create a new array of vtable_indices for default methods
 213 Array<int>* InstanceKlass::create_new_default_vtable_indices(int len, TRAPS) {
 214   Array<int>* vtable_indices = MetadataFactory::new_array<int>(class_loader_data(), len, CHECK_NULL);
 215   assert(default_vtable_indices() == NULL, "only create once");
 216   set_default_vtable_indices(vtable_indices);
 217   return vtable_indices;
 218 }
 219 
 220 InstanceKlass::InstanceKlass(const ClassFileParser& parser, unsigned kind) :
 221   _static_field_size(parser.static_field_size()),
 222   _nonstatic_oop_map_size(nonstatic_oop_map_size(parser.total_oop_map_count())),
 223   _itable_len(parser.itable_size()),
 224   _reference_type(parser.reference_type()) {
 225     set_vtable_length(parser.vtable_size());
 226     set_kind(kind);
 227     set_access_flags(parser.access_flags());
 228     set_is_anonymous(parser.is_anonymous());
 229     set_layout_helper(Klass::instance_layout_helper(parser.layout_size(),
 230                                                     false));
 231 
 232     assert(NULL == _methods, "underlying memory not zeroed?");
 233     assert(is_instance_klass(), "is layout incorrect?");
 234     assert(size_helper() == parser.layout_size(), "incorrect size_helper?");
 235 }
 236 
 237 void InstanceKlass::deallocate_methods(ClassLoaderData* loader_data,
 238                                        Array<Method*>* methods) {
 239   if (methods != NULL && methods != Universe::the_empty_method_array() &&
 240       !methods->is_shared()) {
 241     for (int i = 0; i < methods->length(); i++) {
 242       Method* method = methods->at(i);
 243       if (method == NULL) continue;  // maybe null if error processing
 244       // Only want to delete methods that are not executing for RedefineClasses.
 245       // The previous version will point to them so they're not totally dangling
 246       assert (!method->on_stack(), "shouldn't be called with methods on stack");
 247       MetadataFactory::free_metadata(loader_data, method);
 248     }
 249     MetadataFactory::free_array<Method*>(loader_data, methods);
 250   }
 251 }
 252 
 253 void InstanceKlass::deallocate_interfaces(ClassLoaderData* loader_data,
 254                                           const Klass* super_klass,
 255                                           Array<Klass*>* local_interfaces,
 256                                           Array<Klass*>* transitive_interfaces) {
 257   // Only deallocate transitive interfaces if not empty, same as super class
 258   // or same as local interfaces.  See code in parseClassFile.
 259   Array<Klass*>* ti = transitive_interfaces;
 260   if (ti != Universe::the_empty_klass_array() && ti != local_interfaces) {
 261     // check that the interfaces don't come from super class
 262     Array<Klass*>* sti = (super_klass == NULL) ? NULL :
 263                     InstanceKlass::cast(super_klass)->transitive_interfaces();
 264     if (ti != sti && ti != NULL && !ti->is_shared()) {
 265       MetadataFactory::free_array<Klass*>(loader_data, ti);
 266     }
 267   }
 268 
 269   // local interfaces can be empty
 270   if (local_interfaces != Universe::the_empty_klass_array() &&
 271       local_interfaces != NULL && !local_interfaces->is_shared()) {
 272     MetadataFactory::free_array<Klass*>(loader_data, local_interfaces);
 273   }
 274 }
 275 
 276 // This function deallocates the metadata and C heap pointers that the
 277 // InstanceKlass points to.
 278 void InstanceKlass::deallocate_contents(ClassLoaderData* loader_data) {
 279 
 280   // Orphan the mirror first, CMS thinks it's still live.
 281   if (java_mirror() != NULL) {
 282     java_lang_Class::set_klass(java_mirror(), NULL);
 283   }
 284 
 285   // Need to take this class off the class loader data list.
 286   loader_data->remove_class(this);
 287 
 288   // The array_klass for this class is created later, after error handling.
 289   // For class redefinition, we keep the original class so this scratch class
 290   // doesn't have an array class.  Either way, assert that there is nothing
 291   // to deallocate.
 292   assert(array_klasses() == NULL, "array classes shouldn't be created for this class yet");
 293 
 294   // Release C heap allocated data that this might point to, which includes
 295   // reference counting symbol names.
 296   release_C_heap_structures();
 297 
 298   deallocate_methods(loader_data, methods());
 299   set_methods(NULL);
 300 
 301   if (method_ordering() != NULL &&
 302       method_ordering() != Universe::the_empty_int_array() &&
 303       !method_ordering()->is_shared()) {
 304     MetadataFactory::free_array<int>(loader_data, method_ordering());
 305   }
 306   set_method_ordering(NULL);
 307 
 308   // default methods can be empty
 309   if (default_methods() != NULL &&
 310       default_methods() != Universe::the_empty_method_array() &&
 311       !default_methods()->is_shared()) {
 312     MetadataFactory::free_array<Method*>(loader_data, default_methods());
 313   }
 314   // Do NOT deallocate the default methods, they are owned by superinterfaces.
 315   set_default_methods(NULL);
 316 
 317   // default methods vtable indices can be empty
 318   if (default_vtable_indices() != NULL &&
 319       !default_vtable_indices()->is_shared()) {
 320     MetadataFactory::free_array<int>(loader_data, default_vtable_indices());
 321   }
 322   set_default_vtable_indices(NULL);
 323 
 324 
 325   // This array is in Klass, but remove it with the InstanceKlass since
 326   // this place would be the only caller and it can share memory with transitive
 327   // interfaces.
 328   if (secondary_supers() != NULL &&
 329       secondary_supers() != Universe::the_empty_klass_array() &&
 330       secondary_supers() != transitive_interfaces() &&
 331       !secondary_supers()->is_shared()) {
 332     MetadataFactory::free_array<Klass*>(loader_data, secondary_supers());
 333   }
 334   set_secondary_supers(NULL);
 335 
 336   deallocate_interfaces(loader_data, super(), local_interfaces(), transitive_interfaces());
 337   set_transitive_interfaces(NULL);
 338   set_local_interfaces(NULL);
 339 
 340   if (fields() != NULL && !fields()->is_shared()) {
 341     MetadataFactory::free_array<jushort>(loader_data, fields());
 342   }
 343   set_fields(NULL, 0);
 344 
 345   // If a method from a redefined class is using this constant pool, don't
 346   // delete it, yet.  The new class's previous version will point to this.
 347   if (constants() != NULL) {
 348     assert (!constants()->on_stack(), "shouldn't be called if anything is onstack");
 349     if (!constants()->is_shared()) {
 350       MetadataFactory::free_metadata(loader_data, constants());
 351     }
 352     // Delete any cached resolution errors for the constant pool
 353     SystemDictionary::delete_resolution_error(constants());
 354 
 355     set_constants(NULL);
 356   }
 357 
 358   if (inner_classes() != NULL &&
 359       inner_classes() != Universe::the_empty_short_array() &&
 360       !inner_classes()->is_shared()) {
 361     MetadataFactory::free_array<jushort>(loader_data, inner_classes());
 362   }
 363   set_inner_classes(NULL);
 364 
 365   // We should deallocate the Annotations instance if it's not in shared spaces.
 366   if (annotations() != NULL && !annotations()->is_shared()) {
 367     MetadataFactory::free_metadata(loader_data, annotations());
 368   }
 369   set_annotations(NULL);
 370 }
 371 
 372 bool InstanceKlass::should_be_initialized() const {
 373   return !is_initialized();
 374 }
 375 
 376 klassItable InstanceKlass::itable() const {
 377   return klassItable(const_cast<InstanceKlass*>(this));
 378 }
 379 
 380 void InstanceKlass::eager_initialize(Thread *thread) {
 381   if (!EagerInitialization) return;
 382 
 383   if (this->is_not_initialized()) {
 384     // abort if the the class has a class initializer
 385     if (this->class_initializer() != NULL) return;
 386 
 387     // abort if it is java.lang.Object (initialization is handled in genesis)
 388     Klass* super_klass = super();
 389     if (super_klass == NULL) return;
 390 
 391     // abort if the super class should be initialized
 392     if (!InstanceKlass::cast(super_klass)->is_initialized()) return;
 393 
 394     // call body to expose the this pointer
 395     eager_initialize_impl();
 396   }
 397 }
 398 
 399 // JVMTI spec thinks there are signers and protection domain in the
 400 // instanceKlass.  These accessors pretend these fields are there.
 401 // The hprof specification also thinks these fields are in InstanceKlass.
 402 oop InstanceKlass::protection_domain() const {
 403   // return the protection_domain from the mirror
 404   return java_lang_Class::protection_domain(java_mirror());
 405 }
 406 
 407 // To remove these from requires an incompatible change and CCC request.
 408 objArrayOop InstanceKlass::signers() const {
 409   // return the signers from the mirror
 410   return java_lang_Class::signers(java_mirror());
 411 }
 412 
 413 oop InstanceKlass::init_lock() const {
 414   // return the init lock from the mirror
 415   oop lock = java_lang_Class::init_lock(java_mirror());
 416   // Prevent reordering with any access of initialization state
 417   OrderAccess::loadload();
 418   assert((oop)lock != NULL || !is_not_initialized(), // initialized or in_error state
 419          "only fully initialized state can have a null lock");
 420   return lock;
 421 }
 422 
 423 // Set the initialization lock to null so the object can be GC'ed.  Any racing
 424 // threads to get this lock will see a null lock and will not lock.
 425 // That's okay because they all check for initialized state after getting
 426 // the lock and return.
 427 void InstanceKlass::fence_and_clear_init_lock() {
 428   // make sure previous stores are all done, notably the init_state.
 429   OrderAccess::storestore();
 430   java_lang_Class::set_init_lock(java_mirror(), NULL);
 431   assert(!is_not_initialized(), "class must be initialized now");
 432 }
 433 
 434 void InstanceKlass::eager_initialize_impl() {
 435   EXCEPTION_MARK;
 436   HandleMark hm(THREAD);
 437   Handle h_init_lock(THREAD, init_lock());
 438   ObjectLocker ol(h_init_lock, THREAD, init_lock() != NULL);
 439 
 440   // abort if someone beat us to the initialization
 441   if (!is_not_initialized()) return;  // note: not equivalent to is_initialized()
 442 
 443   ClassState old_state = init_state();
 444   link_class_impl(true, THREAD);
 445   if (HAS_PENDING_EXCEPTION) {
 446     CLEAR_PENDING_EXCEPTION;
 447     // Abort if linking the class throws an exception.
 448 
 449     // Use a test to avoid redundantly resetting the state if there's
 450     // no change.  Set_init_state() asserts that state changes make
 451     // progress, whereas here we might just be spinning in place.
 452     if (old_state != _init_state)
 453       set_init_state(old_state);
 454   } else {
 455     // linking successfull, mark class as initialized
 456     set_init_state(fully_initialized);
 457     fence_and_clear_init_lock();
 458     // trace
 459     if (log_is_enabled(Info, class, init)) {
 460       ResourceMark rm(THREAD);
 461       log_info(class, init)("[Initialized %s without side effects]", external_name());
 462     }
 463   }
 464 }
 465 
 466 
 467 // See "The Virtual Machine Specification" section 2.16.5 for a detailed explanation of the class initialization
 468 // process. The step comments refers to the procedure described in that section.
 469 // Note: implementation moved to static method to expose the this pointer.
 470 void InstanceKlass::initialize(TRAPS) {
 471   if (this->should_be_initialized()) {
 472     initialize_impl(CHECK);
 473     // Note: at this point the class may be initialized
 474     //       OR it may be in the state of being initialized
 475     //       in case of recursive initialization!
 476   } else {
 477     assert(is_initialized(), "sanity check");
 478   }
 479 }
 480 
 481 
 482 bool InstanceKlass::verify_code(bool throw_verifyerror, TRAPS) {
 483   // 1) Verify the bytecodes
 484   Verifier::Mode mode =
 485     throw_verifyerror ? Verifier::ThrowException : Verifier::NoException;
 486   return Verifier::verify(this, mode, should_verify_class(), THREAD);
 487 }
 488 
 489 
 490 // Used exclusively by the shared spaces dump mechanism to prevent
 491 // classes mapped into the shared regions in new VMs from appearing linked.
 492 
 493 void InstanceKlass::unlink_class() {
 494   assert(is_linked(), "must be linked");
 495   _init_state = loaded;
 496 }
 497 
 498 void InstanceKlass::link_class(TRAPS) {
 499   assert(is_loaded(), "must be loaded");
 500   if (!is_linked()) {
 501     link_class_impl(true, CHECK);
 502   }
 503 }
 504 
 505 // Called to verify that a class can link during initialization, without
 506 // throwing a VerifyError.
 507 bool InstanceKlass::link_class_or_fail(TRAPS) {
 508   assert(is_loaded(), "must be loaded");
 509   if (!is_linked()) {
 510     link_class_impl(false, CHECK_false);
 511   }
 512   return is_linked();
 513 }
 514 
 515 bool InstanceKlass::link_class_impl(bool throw_verifyerror, TRAPS) {
 516   if (DumpSharedSpaces && is_in_error_state()) {
 517     // This is for CDS dumping phase only -- we use the in_error_state to indicate that
 518     // the class has failed verification. Throwing the NoClassDefFoundError here is just
 519     // a convenient way to stop repeat attempts to verify the same (bad) class.
 520     //
 521     // Note that the NoClassDefFoundError is not part of the JLS, and should not be thrown
 522     // if we are executing Java code. This is not a problem for CDS dumping phase since
 523     // it doesn't execute any Java code.
 524     ResourceMark rm(THREAD);
 525     THROW_MSG_(vmSymbols::java_lang_NoClassDefFoundError(), external_name(), false);
 526   }
 527   // return if already verified
 528   if (is_linked()) {
 529     return true;
 530   }
 531 
 532   // Timing
 533   // timer handles recursion
 534   assert(THREAD->is_Java_thread(), "non-JavaThread in link_class_impl");
 535   JavaThread* jt = (JavaThread*)THREAD;
 536 
 537   // link super class before linking this class
 538   Klass* super_klass = super();
 539   if (super_klass != NULL) {
 540     if (super_klass->is_interface()) {  // check if super class is an interface
 541       ResourceMark rm(THREAD);
 542       Exceptions::fthrow(
 543         THREAD_AND_LOCATION,
 544         vmSymbols::java_lang_IncompatibleClassChangeError(),
 545         "class %s has interface %s as super class",
 546         external_name(),
 547         super_klass->external_name()
 548       );
 549       return false;
 550     }
 551 
 552     InstanceKlass* ik_super = InstanceKlass::cast(super_klass);
 553     ik_super->link_class_impl(throw_verifyerror, CHECK_false);
 554   }
 555 
 556   // link all interfaces implemented by this class before linking this class
 557   Array<Klass*>* interfaces = local_interfaces();
 558   int num_interfaces = interfaces->length();
 559   for (int index = 0; index < num_interfaces; index++) {
 560     InstanceKlass* interk = InstanceKlass::cast(interfaces->at(index));
 561     interk->link_class_impl(throw_verifyerror, CHECK_false);
 562   }
 563 
 564   // in case the class is linked in the process of linking its superclasses
 565   if (is_linked()) {
 566     return true;
 567   }
 568 
 569   // trace only the link time for this klass that includes
 570   // the verification time
 571   PerfClassTraceTime vmtimer(ClassLoader::perf_class_link_time(),
 572                              ClassLoader::perf_class_link_selftime(),
 573                              ClassLoader::perf_classes_linked(),
 574                              jt->get_thread_stat()->perf_recursion_counts_addr(),
 575                              jt->get_thread_stat()->perf_timers_addr(),
 576                              PerfClassTraceTime::CLASS_LINK);
 577 
 578   // verification & rewriting
 579   {
 580     HandleMark hm(THREAD);
 581     Handle h_init_lock(THREAD, init_lock());
 582     ObjectLocker ol(h_init_lock, THREAD, init_lock() != NULL);
 583     // rewritten will have been set if loader constraint error found
 584     // on an earlier link attempt
 585     // don't verify or rewrite if already rewritten
 586     //
 587 
 588     if (!is_linked()) {
 589       if (!is_rewritten()) {
 590         {
 591           bool verify_ok = verify_code(throw_verifyerror, THREAD);
 592           if (!verify_ok) {
 593             return false;
 594           }
 595         }
 596 
 597         // Just in case a side-effect of verify linked this class already
 598         // (which can sometimes happen since the verifier loads classes
 599         // using custom class loaders, which are free to initialize things)
 600         if (is_linked()) {
 601           return true;
 602         }
 603 
 604         // also sets rewritten
 605         rewrite_class(CHECK_false);
 606       } else if (is_shared()) {
 607         SystemDictionaryShared::check_verification_constraints(this, CHECK_false);
 608       }
 609 
 610       // relocate jsrs and link methods after they are all rewritten
 611       link_methods(CHECK_false);
 612 
 613       // Initialize the vtable and interface table after
 614       // methods have been rewritten since rewrite may
 615       // fabricate new Method*s.
 616       // also does loader constraint checking
 617       //
 618       // initialize_vtable and initialize_itable need to be rerun for
 619       // a shared class if the class is not loaded by the NULL classloader.
 620       ClassLoaderData * loader_data = class_loader_data();
 621       if (!(is_shared() &&
 622             loader_data->is_the_null_class_loader_data())) {
 623         ResourceMark rm(THREAD);
 624         vtable().initialize_vtable(true, CHECK_false);
 625         itable().initialize_itable(true, CHECK_false);
 626       }
 627 #ifdef ASSERT
 628       else {
 629         vtable().verify(tty, true);
 630         // In case itable verification is ever added.
 631         // itable().verify(tty, true);
 632       }
 633 #endif
 634       set_init_state(linked);
 635       if (JvmtiExport::should_post_class_prepare()) {
 636         Thread *thread = THREAD;
 637         assert(thread->is_Java_thread(), "thread->is_Java_thread()");
 638         JvmtiExport::post_class_prepare((JavaThread *) thread, this);
 639       }
 640     }
 641   }
 642   return true;
 643 }
 644 
 645 
 646 // Rewrite the byte codes of all of the methods of a class.
 647 // The rewriter must be called exactly once. Rewriting must happen after
 648 // verification but before the first method of the class is executed.
 649 void InstanceKlass::rewrite_class(TRAPS) {
 650   assert(is_loaded(), "must be loaded");
 651   if (is_rewritten()) {
 652     assert(is_shared(), "rewriting an unshared class?");
 653     return;
 654   }
 655   Rewriter::rewrite(this, CHECK);
 656   set_rewritten();
 657 }
 658 
 659 // Now relocate and link method entry points after class is rewritten.
 660 // This is outside is_rewritten flag. In case of an exception, it can be
 661 // executed more than once.
 662 void InstanceKlass::link_methods(TRAPS) {
 663   int len = methods()->length();
 664   for (int i = len-1; i >= 0; i--) {
 665     methodHandle m(THREAD, methods()->at(i));
 666 
 667     // Set up method entry points for compiler and interpreter    .
 668     m->link_method(m, CHECK);
 669   }
 670 }
 671 
 672 // Eagerly initialize superinterfaces that declare default methods (concrete instance: any access)
 673 void InstanceKlass::initialize_super_interfaces(TRAPS) {
 674   assert (has_nonstatic_concrete_methods(), "caller should have checked this");
 675   for (int i = 0; i < local_interfaces()->length(); ++i) {
 676     Klass* iface = local_interfaces()->at(i);
 677     InstanceKlass* ik = InstanceKlass::cast(iface);
 678 
 679     // Initialization is depth first search ie. we start with top of the inheritance tree
 680     // has_nonstatic_concrete_methods drives searching superinterfaces since it
 681     // means has_nonstatic_concrete_methods in its superinterface hierarchy
 682     if (ik->has_nonstatic_concrete_methods()) {
 683       ik->initialize_super_interfaces(CHECK);
 684     }
 685 
 686     // Only initialize() interfaces that "declare" concrete methods.
 687     if (ik->should_be_initialized() && ik->declares_nonstatic_concrete_methods()) {
 688       ik->initialize(CHECK);
 689     }
 690   }
 691 }
 692 
 693 void InstanceKlass::initialize_impl(TRAPS) {
 694   HandleMark hm(THREAD);
 695 
 696   // Make sure klass is linked (verified) before initialization
 697   // A class could already be verified, since it has been reflected upon.
 698   link_class(CHECK);
 699 
 700   DTRACE_CLASSINIT_PROBE(required, -1);
 701 
 702   bool wait = false;
 703 
 704   // refer to the JVM book page 47 for description of steps
 705   // Step 1
 706   {
 707     Handle h_init_lock(THREAD, init_lock());
 708     ObjectLocker ol(h_init_lock, THREAD, init_lock() != NULL);
 709 
 710     Thread *self = THREAD; // it's passed the current thread
 711 
 712     // Step 2
 713     // If we were to use wait() instead of waitInterruptibly() then
 714     // we might end up throwing IE from link/symbol resolution sites
 715     // that aren't expected to throw.  This would wreak havoc.  See 6320309.
 716     while(is_being_initialized() && !is_reentrant_initialization(self)) {
 717         wait = true;
 718       ol.waitUninterruptibly(CHECK);
 719     }
 720 
 721     // Step 3
 722     if (is_being_initialized() && is_reentrant_initialization(self)) {
 723       DTRACE_CLASSINIT_PROBE_WAIT(recursive, -1, wait);
 724       return;
 725     }
 726 
 727     // Step 4
 728     if (is_initialized()) {
 729       DTRACE_CLASSINIT_PROBE_WAIT(concurrent, -1, wait);
 730       return;
 731     }
 732 
 733     // Step 5
 734     if (is_in_error_state()) {
 735       DTRACE_CLASSINIT_PROBE_WAIT(erroneous, -1, wait);
 736       ResourceMark rm(THREAD);
 737       const char* desc = "Could not initialize class ";
 738       const char* className = external_name();
 739       size_t msglen = strlen(desc) + strlen(className) + 1;
 740       char* message = NEW_RESOURCE_ARRAY(char, msglen);
 741       if (NULL == message) {
 742         // Out of memory: can't create detailed error message
 743         THROW_MSG(vmSymbols::java_lang_NoClassDefFoundError(), className);
 744       } else {
 745         jio_snprintf(message, msglen, "%s%s", desc, className);
 746         THROW_MSG(vmSymbols::java_lang_NoClassDefFoundError(), message);
 747       }
 748     }
 749 
 750     // Step 6
 751     set_init_state(being_initialized);
 752     set_init_thread(self);
 753   }
 754 
 755   // Step 7
 756   // Next, if C is a class rather than an interface, initialize it's super class and super
 757   // interfaces.
 758   if (!is_interface()) {
 759     Klass* super_klass = super();
 760     if (super_klass != NULL && super_klass->should_be_initialized()) {
 761       super_klass->initialize(THREAD);
 762     }
 763     // If C implements any interface that declares a non-static, concrete method,
 764     // the initialization of C triggers initialization of its super interfaces.
 765     // Only need to recurse if has_nonstatic_concrete_methods which includes declaring and
 766     // having a superinterface that declares, non-static, concrete methods
 767     if (!HAS_PENDING_EXCEPTION && has_nonstatic_concrete_methods()) {
 768       initialize_super_interfaces(THREAD);
 769     }
 770 
 771     // If any exceptions, complete abruptly, throwing the same exception as above.
 772     if (HAS_PENDING_EXCEPTION) {
 773       Handle e(THREAD, PENDING_EXCEPTION);
 774       CLEAR_PENDING_EXCEPTION;
 775       {
 776         EXCEPTION_MARK;
 777         // Locks object, set state, and notify all waiting threads
 778         set_initialization_state_and_notify(initialization_error, THREAD);
 779         CLEAR_PENDING_EXCEPTION;
 780       }
 781       DTRACE_CLASSINIT_PROBE_WAIT(super__failed, -1, wait);
 782       THROW_OOP(e());
 783     }
 784   }
 785 
 786 
 787   // Look for aot compiled methods for this klass, including class initializer.
 788   AOTLoader::load_for_klass(this, THREAD);
 789 
 790   // Step 8
 791   {
 792     assert(THREAD->is_Java_thread(), "non-JavaThread in initialize_impl");
 793     JavaThread* jt = (JavaThread*)THREAD;
 794     DTRACE_CLASSINIT_PROBE_WAIT(clinit, -1, wait);
 795     // Timer includes any side effects of class initialization (resolution,
 796     // etc), but not recursive entry into call_class_initializer().
 797     PerfClassTraceTime timer(ClassLoader::perf_class_init_time(),
 798                              ClassLoader::perf_class_init_selftime(),
 799                              ClassLoader::perf_classes_inited(),
 800                              jt->get_thread_stat()->perf_recursion_counts_addr(),
 801                              jt->get_thread_stat()->perf_timers_addr(),
 802                              PerfClassTraceTime::CLASS_CLINIT);
 803     call_class_initializer(THREAD);
 804   }
 805 
 806   // Step 9
 807   if (!HAS_PENDING_EXCEPTION) {
 808     set_initialization_state_and_notify(fully_initialized, CHECK);
 809     {
 810       debug_only(vtable().verify(tty, true);)
 811     }
 812   }
 813   else {
 814     // Step 10 and 11
 815     Handle e(THREAD, PENDING_EXCEPTION);
 816     CLEAR_PENDING_EXCEPTION;
 817     // JVMTI has already reported the pending exception
 818     // JVMTI internal flag reset is needed in order to report ExceptionInInitializerError
 819     JvmtiExport::clear_detected_exception((JavaThread*)THREAD);
 820     {
 821       EXCEPTION_MARK;
 822       set_initialization_state_and_notify(initialization_error, THREAD);
 823       CLEAR_PENDING_EXCEPTION;   // ignore any exception thrown, class initialization error is thrown below
 824       // JVMTI has already reported the pending exception
 825       // JVMTI internal flag reset is needed in order to report ExceptionInInitializerError
 826       JvmtiExport::clear_detected_exception((JavaThread*)THREAD);
 827     }
 828     DTRACE_CLASSINIT_PROBE_WAIT(error, -1, wait);
 829     if (e->is_a(SystemDictionary::Error_klass())) {
 830       THROW_OOP(e());
 831     } else {
 832       JavaCallArguments args(e);
 833       THROW_ARG(vmSymbols::java_lang_ExceptionInInitializerError(),
 834                 vmSymbols::throwable_void_signature(),
 835                 &args);
 836     }
 837   }
 838   DTRACE_CLASSINIT_PROBE_WAIT(end, -1, wait);
 839 }
 840 
 841 
 842 void InstanceKlass::set_initialization_state_and_notify(ClassState state, TRAPS) {
 843   Handle h_init_lock(THREAD, init_lock());
 844   if (init_lock() != NULL) {
 845     ObjectLocker ol(h_init_lock, THREAD);
 846     set_init_state(state);
 847     fence_and_clear_init_lock();
 848     ol.notify_all(CHECK);
 849   } else {
 850     assert(init_lock() != NULL, "The initialization state should never be set twice");
 851     set_init_state(state);
 852   }
 853 }
 854 
 855 // The embedded _implementor field can only record one implementor.
 856 // When there are more than one implementors, the _implementor field
 857 // is set to the interface Klass* itself. Following are the possible
 858 // values for the _implementor field:
 859 //   NULL                  - no implementor
 860 //   implementor Klass*    - one implementor
 861 //   self                  - more than one implementor
 862 //
 863 // The _implementor field only exists for interfaces.
 864 void InstanceKlass::add_implementor(Klass* k) {
 865   assert(Compile_lock->owned_by_self(), "");
 866   assert(is_interface(), "not interface");
 867   // Filter out my subinterfaces.
 868   // (Note: Interfaces are never on the subklass list.)
 869   if (InstanceKlass::cast(k)->is_interface()) return;
 870 
 871   // Filter out subclasses whose supers already implement me.
 872   // (Note: CHA must walk subclasses of direct implementors
 873   // in order to locate indirect implementors.)
 874   Klass* sk = k->super();
 875   if (sk != NULL && InstanceKlass::cast(sk)->implements_interface(this))
 876     // We only need to check one immediate superclass, since the
 877     // implements_interface query looks at transitive_interfaces.
 878     // Any supers of the super have the same (or fewer) transitive_interfaces.
 879     return;
 880 
 881   Klass* ik = implementor();
 882   if (ik == NULL) {
 883     set_implementor(k);
 884   } else if (ik != this) {
 885     // There is already an implementor. Use itself as an indicator of
 886     // more than one implementors.
 887     set_implementor(this);
 888   }
 889 
 890   // The implementor also implements the transitive_interfaces
 891   for (int index = 0; index < local_interfaces()->length(); index++) {
 892     InstanceKlass::cast(local_interfaces()->at(index))->add_implementor(k);
 893   }
 894 }
 895 
 896 void InstanceKlass::init_implementor() {
 897   if (is_interface()) {
 898     set_implementor(NULL);
 899   }
 900 }
 901 
 902 
 903 void InstanceKlass::process_interfaces(Thread *thread) {
 904   // link this class into the implementors list of every interface it implements
 905   for (int i = local_interfaces()->length() - 1; i >= 0; i--) {
 906     assert(local_interfaces()->at(i)->is_klass(), "must be a klass");
 907     InstanceKlass* interf = InstanceKlass::cast(local_interfaces()->at(i));
 908     assert(interf->is_interface(), "expected interface");
 909     interf->add_implementor(this);
 910   }
 911 }
 912 
 913 bool InstanceKlass::can_be_primary_super_slow() const {
 914   if (is_interface())
 915     return false;
 916   else
 917     return Klass::can_be_primary_super_slow();
 918 }
 919 
 920 GrowableArray<Klass*>* InstanceKlass::compute_secondary_supers(int num_extra_slots) {
 921   // The secondaries are the implemented interfaces.
 922   Array<Klass*>* interfaces = transitive_interfaces();
 923   int num_secondaries = num_extra_slots + interfaces->length();
 924   if (num_secondaries == 0) {
 925     // Must share this for correct bootstrapping!
 926     set_secondary_supers(Universe::the_empty_klass_array());
 927     return NULL;
 928   } else if (num_extra_slots == 0) {
 929     // The secondary super list is exactly the same as the transitive interfaces.
 930     // Redefine classes has to be careful not to delete this!
 931     set_secondary_supers(interfaces);
 932     return NULL;
 933   } else {
 934     // Copy transitive interfaces to a temporary growable array to be constructed
 935     // into the secondary super list with extra slots.
 936     GrowableArray<Klass*>* secondaries = new GrowableArray<Klass*>(interfaces->length());
 937     for (int i = 0; i < interfaces->length(); i++) {
 938       secondaries->push(interfaces->at(i));
 939     }
 940     return secondaries;
 941   }
 942 }
 943 
 944 bool InstanceKlass::compute_is_subtype_of(Klass* k) {
 945   if (k->is_interface()) {
 946     return implements_interface(k);
 947   } else {
 948     return Klass::compute_is_subtype_of(k);
 949   }
 950 }
 951 
 952 bool InstanceKlass::implements_interface(Klass* k) const {
 953   if (this == k) return true;
 954   assert(k->is_interface(), "should be an interface class");
 955   for (int i = 0; i < transitive_interfaces()->length(); i++) {
 956     if (transitive_interfaces()->at(i) == k) {
 957       return true;
 958     }
 959   }
 960   return false;
 961 }
 962 
 963 bool InstanceKlass::is_same_or_direct_interface(Klass *k) const {
 964   // Verify direct super interface
 965   if (this == k) return true;
 966   assert(k->is_interface(), "should be an interface class");
 967   for (int i = 0; i < local_interfaces()->length(); i++) {
 968     if (local_interfaces()->at(i) == k) {
 969       return true;
 970     }
 971   }
 972   return false;
 973 }
 974 
 975 objArrayOop InstanceKlass::allocate_objArray(int n, int length, TRAPS) {
 976   if (length < 0) THROW_0(vmSymbols::java_lang_NegativeArraySizeException());
 977   if (length > arrayOopDesc::max_array_length(T_OBJECT)) {
 978     report_java_out_of_memory("Requested array size exceeds VM limit");
 979     JvmtiExport::post_array_size_exhausted();
 980     THROW_OOP_0(Universe::out_of_memory_error_array_size());
 981   }
 982   int size = objArrayOopDesc::object_size(length);
 983   Klass* ak = array_klass(n, CHECK_NULL);
 984   objArrayOop o =
 985     (objArrayOop)CollectedHeap::array_allocate(ak, size, length, CHECK_NULL);
 986   return o;
 987 }
 988 
 989 instanceOop InstanceKlass::register_finalizer(instanceOop i, TRAPS) {
 990   if (TraceFinalizerRegistration) {
 991     tty->print("Registered ");
 992     i->print_value_on(tty);
 993     tty->print_cr(" (" INTPTR_FORMAT ") as finalizable", p2i(i));
 994   }
 995   instanceHandle h_i(THREAD, i);
 996   // Pass the handle as argument, JavaCalls::call expects oop as jobjects
 997   JavaValue result(T_VOID);
 998   JavaCallArguments args(h_i);
 999   methodHandle mh (THREAD, Universe::finalizer_register_method());
1000   JavaCalls::call(&result, mh, &args, CHECK_NULL);
1001   return h_i();
1002 }
1003 
1004 instanceOop InstanceKlass::allocate_instance(TRAPS) {
1005   bool has_finalizer_flag = has_finalizer(); // Query before possible GC
1006   int size = size_helper();  // Query before forming handle.
1007 
1008   instanceOop i;
1009 
1010   i = (instanceOop)CollectedHeap::obj_allocate(this, size, CHECK_NULL);
1011   if (has_finalizer_flag && !RegisterFinalizersAtInit) {
1012     i = register_finalizer(i, CHECK_NULL);
1013   }
1014   return i;
1015 }
1016 
1017 void InstanceKlass::check_valid_for_instantiation(bool throwError, TRAPS) {
1018   if (is_interface() || is_abstract()) {
1019     ResourceMark rm(THREAD);
1020     THROW_MSG(throwError ? vmSymbols::java_lang_InstantiationError()
1021               : vmSymbols::java_lang_InstantiationException(), external_name());
1022   }
1023   if (this == SystemDictionary::Class_klass()) {
1024     ResourceMark rm(THREAD);
1025     THROW_MSG(throwError ? vmSymbols::java_lang_IllegalAccessError()
1026               : vmSymbols::java_lang_IllegalAccessException(), external_name());
1027   }
1028 }
1029 
1030 Klass* InstanceKlass::array_klass_impl(bool or_null, int n, TRAPS) {
1031   // Need load-acquire for lock-free read
1032   if (array_klasses_acquire() == NULL) {
1033     if (or_null) return NULL;
1034 
1035     ResourceMark rm;
1036     JavaThread *jt = (JavaThread *)THREAD;
1037     {
1038       // Atomic creation of array_klasses
1039       MutexLocker mc(Compile_lock, THREAD);   // for vtables
1040       MutexLocker ma(MultiArray_lock, THREAD);
1041 
1042       // Check if update has already taken place
1043       if (array_klasses() == NULL) {
1044         Klass*    k = ObjArrayKlass::allocate_objArray_klass(class_loader_data(), 1, this, CHECK_NULL);
1045         // use 'release' to pair with lock-free load
1046         release_set_array_klasses(k);
1047       }
1048     }
1049   }
1050   // _this will always be set at this point
1051   ObjArrayKlass* oak = (ObjArrayKlass*)array_klasses();
1052   if (or_null) {
1053     return oak->array_klass_or_null(n);
1054   }
1055   return oak->array_klass(n, THREAD);
1056 }
1057 
1058 Klass* InstanceKlass::array_klass_impl(bool or_null, TRAPS) {
1059   return array_klass_impl(or_null, 1, THREAD);
1060 }
1061 
1062 static int call_class_initializer_counter = 0;   // for debugging
1063 
1064 Method* InstanceKlass::class_initializer() const {
1065   Method* clinit = find_method(
1066       vmSymbols::class_initializer_name(), vmSymbols::void_method_signature());
1067   if (clinit != NULL && clinit->has_valid_initializer_flags()) {
1068     return clinit;
1069   }
1070   return NULL;
1071 }
1072 
1073 void InstanceKlass::call_class_initializer(TRAPS) {
1074   if (ReplayCompiles &&
1075       (ReplaySuppressInitializers == 1 ||
1076        ReplaySuppressInitializers >= 2 && class_loader() != NULL)) {
1077     // Hide the existence of the initializer for the purpose of replaying the compile
1078     return;
1079   }
1080 
1081   methodHandle h_method(THREAD, class_initializer());
1082   assert(!is_initialized(), "we cannot initialize twice");
1083   if (log_is_enabled(Info, class, init)) {
1084     ResourceMark rm;
1085     outputStream* log = Log(class, init)::info_stream();
1086     log->print("%d Initializing ", call_class_initializer_counter++);
1087     name()->print_value_on(log);
1088     log->print_cr("%s (" INTPTR_FORMAT ")", h_method() == NULL ? "(no method)" : "", p2i(this));
1089   }
1090   if (h_method() != NULL) {
1091     JavaCallArguments args; // No arguments
1092     JavaValue result(T_VOID);
1093     JavaCalls::call(&result, h_method, &args, CHECK); // Static call (no args)
1094   }
1095 }
1096 
1097 
1098 void InstanceKlass::mask_for(const methodHandle& method, int bci,
1099   InterpreterOopMap* entry_for) {
1100   // Lazily create the _oop_map_cache at first request
1101   // Lock-free access requires load_ptr_acquire.
1102   OopMapCache* oop_map_cache =
1103       static_cast<OopMapCache*>(OrderAccess::load_ptr_acquire(&_oop_map_cache));
1104   if (oop_map_cache == NULL) {
1105     MutexLocker x(OopMapCacheAlloc_lock);
1106     // Check if _oop_map_cache was allocated while we were waiting for this lock
1107     if ((oop_map_cache = _oop_map_cache) == NULL) {
1108       oop_map_cache = new OopMapCache();
1109       // Ensure _oop_map_cache is stable, since it is examined without a lock
1110       OrderAccess::release_store_ptr(&_oop_map_cache, oop_map_cache);
1111     }
1112   }
1113   // _oop_map_cache is constant after init; lookup below does its own locking.
1114   oop_map_cache->lookup(method, bci, entry_for);
1115 }
1116 
1117 
1118 bool InstanceKlass::find_local_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
1119   for (JavaFieldStream fs(this); !fs.done(); fs.next()) {
1120     Symbol* f_name = fs.name();
1121     Symbol* f_sig  = fs.signature();
1122     if (f_name == name && f_sig == sig) {
1123       fd->reinitialize(const_cast<InstanceKlass*>(this), fs.index());
1124       return true;
1125     }
1126   }
1127   return false;
1128 }
1129 
1130 
1131 Klass* InstanceKlass::find_interface_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
1132   const int n = local_interfaces()->length();
1133   for (int i = 0; i < n; i++) {
1134     Klass* intf1 = local_interfaces()->at(i);
1135     assert(intf1->is_interface(), "just checking type");
1136     // search for field in current interface
1137     if (InstanceKlass::cast(intf1)->find_local_field(name, sig, fd)) {
1138       assert(fd->is_static(), "interface field must be static");
1139       return intf1;
1140     }
1141     // search for field in direct superinterfaces
1142     Klass* intf2 = InstanceKlass::cast(intf1)->find_interface_field(name, sig, fd);
1143     if (intf2 != NULL) return intf2;
1144   }
1145   // otherwise field lookup fails
1146   return NULL;
1147 }
1148 
1149 
1150 Klass* InstanceKlass::find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
1151   // search order according to newest JVM spec (5.4.3.2, p.167).
1152   // 1) search for field in current klass
1153   if (find_local_field(name, sig, fd)) {
1154     return const_cast<InstanceKlass*>(this);
1155   }
1156   // 2) search for field recursively in direct superinterfaces
1157   { Klass* intf = find_interface_field(name, sig, fd);
1158     if (intf != NULL) return intf;
1159   }
1160   // 3) apply field lookup recursively if superclass exists
1161   { Klass* supr = super();
1162     if (supr != NULL) return InstanceKlass::cast(supr)->find_field(name, sig, fd);
1163   }
1164   // 4) otherwise field lookup fails
1165   return NULL;
1166 }
1167 
1168 
1169 Klass* InstanceKlass::find_field(Symbol* name, Symbol* sig, bool is_static, fieldDescriptor* fd) const {
1170   // search order according to newest JVM spec (5.4.3.2, p.167).
1171   // 1) search for field in current klass
1172   if (find_local_field(name, sig, fd)) {
1173     if (fd->is_static() == is_static) return const_cast<InstanceKlass*>(this);
1174   }
1175   // 2) search for field recursively in direct superinterfaces
1176   if (is_static) {
1177     Klass* intf = find_interface_field(name, sig, fd);
1178     if (intf != NULL) return intf;
1179   }
1180   // 3) apply field lookup recursively if superclass exists
1181   { Klass* supr = super();
1182     if (supr != NULL) return InstanceKlass::cast(supr)->find_field(name, sig, is_static, fd);
1183   }
1184   // 4) otherwise field lookup fails
1185   return NULL;
1186 }
1187 
1188 
1189 bool InstanceKlass::find_local_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const {
1190   for (JavaFieldStream fs(this); !fs.done(); fs.next()) {
1191     if (fs.offset() == offset) {
1192       fd->reinitialize(const_cast<InstanceKlass*>(this), fs.index());
1193       if (fd->is_static() == is_static) return true;
1194     }
1195   }
1196   return false;
1197 }
1198 
1199 
1200 bool InstanceKlass::find_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const {
1201   Klass* klass = const_cast<InstanceKlass*>(this);
1202   while (klass != NULL) {
1203     if (InstanceKlass::cast(klass)->find_local_field_from_offset(offset, is_static, fd)) {
1204       return true;
1205     }
1206     klass = klass->super();
1207   }
1208   return false;
1209 }
1210 
1211 
1212 void InstanceKlass::methods_do(void f(Method* method)) {
1213   // Methods aren't stable until they are loaded.  This can be read outside
1214   // a lock through the ClassLoaderData for profiling
1215   if (!is_loaded()) {
1216     return;
1217   }
1218 
1219   int len = methods()->length();
1220   for (int index = 0; index < len; index++) {
1221     Method* m = methods()->at(index);
1222     assert(m->is_method(), "must be method");
1223     f(m);
1224   }
1225 }
1226 
1227 
1228 void InstanceKlass::do_local_static_fields(FieldClosure* cl) {
1229   for (JavaFieldStream fs(this); !fs.done(); fs.next()) {
1230     if (fs.access_flags().is_static()) {
1231       fieldDescriptor& fd = fs.field_descriptor();
1232       cl->do_field(&fd);
1233     }
1234   }
1235 }
1236 
1237 
1238 void InstanceKlass::do_local_static_fields(void f(fieldDescriptor*, Handle, TRAPS), Handle mirror, TRAPS) {
1239   for (JavaFieldStream fs(this); !fs.done(); fs.next()) {
1240     if (fs.access_flags().is_static()) {
1241       fieldDescriptor& fd = fs.field_descriptor();
1242       f(&fd, mirror, CHECK);
1243     }
1244   }
1245 }
1246 
1247 
1248 static int compare_fields_by_offset(int* a, int* b) {
1249   return a[0] - b[0];
1250 }
1251 
1252 void InstanceKlass::do_nonstatic_fields(FieldClosure* cl) {
1253   InstanceKlass* super = superklass();
1254   if (super != NULL) {
1255     super->do_nonstatic_fields(cl);
1256   }
1257   fieldDescriptor fd;
1258   int length = java_fields_count();
1259   // In DebugInfo nonstatic fields are sorted by offset.
1260   int* fields_sorted = NEW_C_HEAP_ARRAY(int, 2*(length+1), mtClass);
1261   int j = 0;
1262   for (int i = 0; i < length; i += 1) {
1263     fd.reinitialize(this, i);
1264     if (!fd.is_static()) {
1265       fields_sorted[j + 0] = fd.offset();
1266       fields_sorted[j + 1] = i;
1267       j += 2;
1268     }
1269   }
1270   if (j > 0) {
1271     length = j;
1272     // _sort_Fn is defined in growableArray.hpp.
1273     qsort(fields_sorted, length/2, 2*sizeof(int), (_sort_Fn)compare_fields_by_offset);
1274     for (int i = 0; i < length; i += 2) {
1275       fd.reinitialize(this, fields_sorted[i + 1]);
1276       assert(!fd.is_static() && fd.offset() == fields_sorted[i], "only nonstatic fields");
1277       cl->do_field(&fd);
1278     }
1279   }
1280   FREE_C_HEAP_ARRAY(int, fields_sorted);
1281 }
1282 
1283 
1284 void InstanceKlass::array_klasses_do(void f(Klass* k, TRAPS), TRAPS) {
1285   if (array_klasses() != NULL)
1286     ArrayKlass::cast(array_klasses())->array_klasses_do(f, THREAD);
1287 }
1288 
1289 void InstanceKlass::array_klasses_do(void f(Klass* k)) {
1290   if (array_klasses() != NULL)
1291     ArrayKlass::cast(array_klasses())->array_klasses_do(f);
1292 }
1293 
1294 #ifdef ASSERT
1295 static int linear_search(const Array<Method*>* methods,
1296                          const Symbol* name,
1297                          const Symbol* signature) {
1298   const int len = methods->length();
1299   for (int index = 0; index < len; index++) {
1300     const Method* const m = methods->at(index);
1301     assert(m->is_method(), "must be method");
1302     if (m->signature() == signature && m->name() == name) {
1303        return index;
1304     }
1305   }
1306   return -1;
1307 }
1308 #endif
1309 
1310 static int binary_search(const Array<Method*>* methods, const Symbol* name) {
1311   int len = methods->length();
1312   // methods are sorted, so do binary search
1313   int l = 0;
1314   int h = len - 1;
1315   while (l <= h) {
1316     int mid = (l + h) >> 1;
1317     Method* m = methods->at(mid);
1318     assert(m->is_method(), "must be method");
1319     int res = m->name()->fast_compare(name);
1320     if (res == 0) {
1321       return mid;
1322     } else if (res < 0) {
1323       l = mid + 1;
1324     } else {
1325       h = mid - 1;
1326     }
1327   }
1328   return -1;
1329 }
1330 
1331 // find_method looks up the name/signature in the local methods array
1332 Method* InstanceKlass::find_method(const Symbol* name,
1333                                    const Symbol* signature) const {
1334   return find_method_impl(name, signature, find_overpass, find_static, find_private);
1335 }
1336 
1337 Method* InstanceKlass::find_method_impl(const Symbol* name,
1338                                         const Symbol* signature,
1339                                         OverpassLookupMode overpass_mode,
1340                                         StaticLookupMode static_mode,
1341                                         PrivateLookupMode private_mode) const {
1342   return InstanceKlass::find_method_impl(methods(),
1343                                          name,
1344                                          signature,
1345                                          overpass_mode,
1346                                          static_mode,
1347                                          private_mode);
1348 }
1349 
1350 // find_instance_method looks up the name/signature in the local methods array
1351 // and skips over static methods
1352 Method* InstanceKlass::find_instance_method(const Array<Method*>* methods,
1353                                             const Symbol* name,
1354                                             const Symbol* signature) {
1355   Method* const meth = InstanceKlass::find_method_impl(methods,
1356                                                  name,
1357                                                  signature,
1358                                                  find_overpass,
1359                                                  skip_static,
1360                                                  find_private);
1361   assert(((meth == NULL) || !meth->is_static()),
1362     "find_instance_method should have skipped statics");
1363   return meth;
1364 }
1365 
1366 // find_instance_method looks up the name/signature in the local methods array
1367 // and skips over static methods
1368 Method* InstanceKlass::find_instance_method(const Symbol* name, const Symbol* signature) const {
1369   return InstanceKlass::find_instance_method(methods(), name, signature);
1370 }
1371 
1372 // Find looks up the name/signature in the local methods array
1373 // and filters on the overpass, static and private flags
1374 // This returns the first one found
1375 // note that the local methods array can have up to one overpass, one static
1376 // and one instance (private or not) with the same name/signature
1377 Method* InstanceKlass::find_local_method(const Symbol* name,
1378                                          const Symbol* signature,
1379                                          OverpassLookupMode overpass_mode,
1380                                          StaticLookupMode static_mode,
1381                                          PrivateLookupMode private_mode) const {
1382   return InstanceKlass::find_method_impl(methods(),
1383                                          name,
1384                                          signature,
1385                                          overpass_mode,
1386                                          static_mode,
1387                                          private_mode);
1388 }
1389 
1390 // Find looks up the name/signature in the local methods array
1391 // and filters on the overpass, static and private flags
1392 // This returns the first one found
1393 // note that the local methods array can have up to one overpass, one static
1394 // and one instance (private or not) with the same name/signature
1395 Method* InstanceKlass::find_local_method(const Array<Method*>* methods,
1396                                          const Symbol* name,
1397                                          const Symbol* signature,
1398                                          OverpassLookupMode overpass_mode,
1399                                          StaticLookupMode static_mode,
1400                                          PrivateLookupMode private_mode) {
1401   return InstanceKlass::find_method_impl(methods,
1402                                          name,
1403                                          signature,
1404                                          overpass_mode,
1405                                          static_mode,
1406                                          private_mode);
1407 }
1408 
1409 Method* InstanceKlass::find_method(const Array<Method*>* methods,
1410                                    const Symbol* name,
1411                                    const Symbol* signature) {
1412   return InstanceKlass::find_method_impl(methods,
1413                                          name,
1414                                          signature,
1415                                          find_overpass,
1416                                          find_static,
1417                                          find_private);
1418 }
1419 
1420 Method* InstanceKlass::find_method_impl(const Array<Method*>* methods,
1421                                         const Symbol* name,
1422                                         const Symbol* signature,
1423                                         OverpassLookupMode overpass_mode,
1424                                         StaticLookupMode static_mode,
1425                                         PrivateLookupMode private_mode) {
1426   int hit = find_method_index(methods, name, signature, overpass_mode, static_mode, private_mode);
1427   return hit >= 0 ? methods->at(hit): NULL;
1428 }
1429 
1430 // true if method matches signature and conforms to skipping_X conditions.
1431 static bool method_matches(const Method* m,
1432                            const Symbol* signature,
1433                            bool skipping_overpass,
1434                            bool skipping_static,
1435                            bool skipping_private) {
1436   return ((m->signature() == signature) &&
1437     (!skipping_overpass || !m->is_overpass()) &&
1438     (!skipping_static || !m->is_static()) &&
1439     (!skipping_private || !m->is_private()));
1440 }
1441 
1442 // Used directly for default_methods to find the index into the
1443 // default_vtable_indices, and indirectly by find_method
1444 // find_method_index looks in the local methods array to return the index
1445 // of the matching name/signature. If, overpass methods are being ignored,
1446 // the search continues to find a potential non-overpass match.  This capability
1447 // is important during method resolution to prefer a static method, for example,
1448 // over an overpass method.
1449 // There is the possibility in any _method's array to have the same name/signature
1450 // for a static method, an overpass method and a local instance method
1451 // To correctly catch a given method, the search criteria may need
1452 // to explicitly skip the other two. For local instance methods, it
1453 // is often necessary to skip private methods
1454 int InstanceKlass::find_method_index(const Array<Method*>* methods,
1455                                      const Symbol* name,
1456                                      const Symbol* signature,
1457                                      OverpassLookupMode overpass_mode,
1458                                      StaticLookupMode static_mode,
1459                                      PrivateLookupMode private_mode) {
1460   const bool skipping_overpass = (overpass_mode == skip_overpass);
1461   const bool skipping_static = (static_mode == skip_static);
1462   const bool skipping_private = (private_mode == skip_private);
1463   const int hit = binary_search(methods, name);
1464   if (hit != -1) {
1465     const Method* const m = methods->at(hit);
1466 
1467     // Do linear search to find matching signature.  First, quick check
1468     // for common case, ignoring overpasses if requested.
1469     if (method_matches(m, signature, skipping_overpass, skipping_static, skipping_private)) {
1470           return hit;
1471     }
1472 
1473     // search downwards through overloaded methods
1474     int i;
1475     for (i = hit - 1; i >= 0; --i) {
1476         const Method* const m = methods->at(i);
1477         assert(m->is_method(), "must be method");
1478         if (m->name() != name) {
1479           break;
1480         }
1481         if (method_matches(m, signature, skipping_overpass, skipping_static, skipping_private)) {
1482           return i;
1483         }
1484     }
1485     // search upwards
1486     for (i = hit + 1; i < methods->length(); ++i) {
1487         const Method* const m = methods->at(i);
1488         assert(m->is_method(), "must be method");
1489         if (m->name() != name) {
1490           break;
1491         }
1492         if (method_matches(m, signature, skipping_overpass, skipping_static, skipping_private)) {
1493           return i;
1494         }
1495     }
1496     // not found
1497 #ifdef ASSERT
1498     const int index = (skipping_overpass || skipping_static || skipping_private) ? -1 :
1499       linear_search(methods, name, signature);
1500     assert(-1 == index, "binary search should have found entry %d", index);
1501 #endif
1502   }
1503   return -1;
1504 }
1505 
1506 int InstanceKlass::find_method_by_name(const Symbol* name, int* end) const {
1507   return find_method_by_name(methods(), name, end);
1508 }
1509 
1510 int InstanceKlass::find_method_by_name(const Array<Method*>* methods,
1511                                        const Symbol* name,
1512                                        int* end_ptr) {
1513   assert(end_ptr != NULL, "just checking");
1514   int start = binary_search(methods, name);
1515   int end = start + 1;
1516   if (start != -1) {
1517     while (start - 1 >= 0 && (methods->at(start - 1))->name() == name) --start;
1518     while (end < methods->length() && (methods->at(end))->name() == name) ++end;
1519     *end_ptr = end;
1520     return start;
1521   }
1522   return -1;
1523 }
1524 
1525 // uncached_lookup_method searches both the local class methods array and all
1526 // superclasses methods arrays, skipping any overpass methods in superclasses.
1527 Method* InstanceKlass::uncached_lookup_method(const Symbol* name,
1528                                               const Symbol* signature,
1529                                               OverpassLookupMode overpass_mode) const {
1530   OverpassLookupMode overpass_local_mode = overpass_mode;
1531   const Klass* klass = this;
1532   while (klass != NULL) {
1533     Method* const method = InstanceKlass::cast(klass)->find_method_impl(name,
1534                                                                         signature,
1535                                                                         overpass_local_mode,
1536                                                                         find_static,
1537                                                                         find_private);
1538     if (method != NULL) {
1539       return method;
1540     }
1541     klass = klass->super();
1542     overpass_local_mode = skip_overpass;   // Always ignore overpass methods in superclasses
1543   }
1544   return NULL;
1545 }
1546 
1547 #ifdef ASSERT
1548 // search through class hierarchy and return true if this class or
1549 // one of the superclasses was redefined
1550 bool InstanceKlass::has_redefined_this_or_super() const {
1551   const Klass* klass = this;
1552   while (klass != NULL) {
1553     if (InstanceKlass::cast(klass)->has_been_redefined()) {
1554       return true;
1555     }
1556     klass = klass->super();
1557   }
1558   return false;
1559 }
1560 #endif
1561 
1562 // lookup a method in the default methods list then in all transitive interfaces
1563 // Do NOT return private or static methods
1564 Method* InstanceKlass::lookup_method_in_ordered_interfaces(Symbol* name,
1565                                                          Symbol* signature) const {
1566   Method* m = NULL;
1567   if (default_methods() != NULL) {
1568     m = find_method(default_methods(), name, signature);
1569   }
1570   // Look up interfaces
1571   if (m == NULL) {
1572     m = lookup_method_in_all_interfaces(name, signature, find_defaults);
1573   }
1574   return m;
1575 }
1576 
1577 // lookup a method in all the interfaces that this class implements
1578 // Do NOT return private or static methods, new in JDK8 which are not externally visible
1579 // They should only be found in the initial InterfaceMethodRef
1580 Method* InstanceKlass::lookup_method_in_all_interfaces(Symbol* name,
1581                                                        Symbol* signature,
1582                                                        DefaultsLookupMode defaults_mode) const {
1583   Array<Klass*>* all_ifs = transitive_interfaces();
1584   int num_ifs = all_ifs->length();
1585   InstanceKlass *ik = NULL;
1586   for (int i = 0; i < num_ifs; i++) {
1587     ik = InstanceKlass::cast(all_ifs->at(i));
1588     Method* m = ik->lookup_method(name, signature);
1589     if (m != NULL && m->is_public() && !m->is_static() &&
1590         ((defaults_mode != skip_defaults) || !m->is_default_method())) {
1591       return m;
1592     }
1593   }
1594   return NULL;
1595 }
1596 
1597 /* jni_id_for_impl for jfieldIds only */
1598 JNIid* InstanceKlass::jni_id_for_impl(int offset) {
1599   MutexLocker ml(JfieldIdCreation_lock);
1600   // Retry lookup after we got the lock
1601   JNIid* probe = jni_ids() == NULL ? NULL : jni_ids()->find(offset);
1602   if (probe == NULL) {
1603     // Slow case, allocate new static field identifier
1604     probe = new JNIid(this, offset, jni_ids());
1605     set_jni_ids(probe);
1606   }
1607   return probe;
1608 }
1609 
1610 
1611 /* jni_id_for for jfieldIds only */
1612 JNIid* InstanceKlass::jni_id_for(int offset) {
1613   JNIid* probe = jni_ids() == NULL ? NULL : jni_ids()->find(offset);
1614   if (probe == NULL) {
1615     probe = jni_id_for_impl(offset);
1616   }
1617   return probe;
1618 }
1619 
1620 u2 InstanceKlass::enclosing_method_data(int offset) const {
1621   const Array<jushort>* const inner_class_list = inner_classes();
1622   if (inner_class_list == NULL) {
1623     return 0;
1624   }
1625   const int length = inner_class_list->length();
1626   if (length % inner_class_next_offset == 0) {
1627     return 0;
1628   }
1629   const int index = length - enclosing_method_attribute_size;
1630   assert(offset < enclosing_method_attribute_size, "invalid offset");
1631   return inner_class_list->at(index + offset);
1632 }
1633 
1634 void InstanceKlass::set_enclosing_method_indices(u2 class_index,
1635                                                  u2 method_index) {
1636   Array<jushort>* inner_class_list = inner_classes();
1637   assert (inner_class_list != NULL, "_inner_classes list is not set up");
1638   int length = inner_class_list->length();
1639   if (length % inner_class_next_offset == enclosing_method_attribute_size) {
1640     int index = length - enclosing_method_attribute_size;
1641     inner_class_list->at_put(
1642       index + enclosing_method_class_index_offset, class_index);
1643     inner_class_list->at_put(
1644       index + enclosing_method_method_index_offset, method_index);
1645   }
1646 }
1647 
1648 // Lookup or create a jmethodID.
1649 // This code is called by the VMThread and JavaThreads so the
1650 // locking has to be done very carefully to avoid deadlocks
1651 // and/or other cache consistency problems.
1652 //
1653 jmethodID InstanceKlass::get_jmethod_id(const methodHandle& method_h) {
1654   size_t idnum = (size_t)method_h->method_idnum();
1655   jmethodID* jmeths = methods_jmethod_ids_acquire();
1656   size_t length = 0;
1657   jmethodID id = NULL;
1658 
1659   // We use a double-check locking idiom here because this cache is
1660   // performance sensitive. In the normal system, this cache only
1661   // transitions from NULL to non-NULL which is safe because we use
1662   // release_set_methods_jmethod_ids() to advertise the new cache.
1663   // A partially constructed cache should never be seen by a racing
1664   // thread. We also use release_store_ptr() to save a new jmethodID
1665   // in the cache so a partially constructed jmethodID should never be
1666   // seen either. Cache reads of existing jmethodIDs proceed without a
1667   // lock, but cache writes of a new jmethodID requires uniqueness and
1668   // creation of the cache itself requires no leaks so a lock is
1669   // generally acquired in those two cases.
1670   //
1671   // If the RedefineClasses() API has been used, then this cache can
1672   // grow and we'll have transitions from non-NULL to bigger non-NULL.
1673   // Cache creation requires no leaks and we require safety between all
1674   // cache accesses and freeing of the old cache so a lock is generally
1675   // acquired when the RedefineClasses() API has been used.
1676 
1677   if (jmeths != NULL) {
1678     // the cache already exists
1679     if (!idnum_can_increment()) {
1680       // the cache can't grow so we can just get the current values
1681       get_jmethod_id_length_value(jmeths, idnum, &length, &id);
1682     } else {
1683       // cache can grow so we have to be more careful
1684       if (Threads::number_of_threads() == 0 ||
1685           SafepointSynchronize::is_at_safepoint()) {
1686         // we're single threaded or at a safepoint - no locking needed
1687         get_jmethod_id_length_value(jmeths, idnum, &length, &id);
1688       } else {
1689         MutexLocker ml(JmethodIdCreation_lock);
1690         get_jmethod_id_length_value(jmeths, idnum, &length, &id);
1691       }
1692     }
1693   }
1694   // implied else:
1695   // we need to allocate a cache so default length and id values are good
1696 
1697   if (jmeths == NULL ||   // no cache yet
1698       length <= idnum ||  // cache is too short
1699       id == NULL) {       // cache doesn't contain entry
1700 
1701     // This function can be called by the VMThread so we have to do all
1702     // things that might block on a safepoint before grabbing the lock.
1703     // Otherwise, we can deadlock with the VMThread or have a cache
1704     // consistency issue. These vars keep track of what we might have
1705     // to free after the lock is dropped.
1706     jmethodID  to_dealloc_id     = NULL;
1707     jmethodID* to_dealloc_jmeths = NULL;
1708 
1709     // may not allocate new_jmeths or use it if we allocate it
1710     jmethodID* new_jmeths = NULL;
1711     if (length <= idnum) {
1712       // allocate a new cache that might be used
1713       size_t size = MAX2(idnum+1, (size_t)idnum_allocated_count());
1714       new_jmeths = NEW_C_HEAP_ARRAY(jmethodID, size+1, mtClass);
1715       memset(new_jmeths, 0, (size+1)*sizeof(jmethodID));
1716       // cache size is stored in element[0], other elements offset by one
1717       new_jmeths[0] = (jmethodID)size;
1718     }
1719 
1720     // allocate a new jmethodID that might be used
1721     jmethodID new_id = NULL;
1722     if (method_h->is_old() && !method_h->is_obsolete()) {
1723       // The method passed in is old (but not obsolete), we need to use the current version
1724       Method* current_method = method_with_idnum((int)idnum);
1725       assert(current_method != NULL, "old and but not obsolete, so should exist");
1726       new_id = Method::make_jmethod_id(class_loader_data(), current_method);
1727     } else {
1728       // It is the current version of the method or an obsolete method,
1729       // use the version passed in
1730       new_id = Method::make_jmethod_id(class_loader_data(), method_h());
1731     }
1732 
1733     if (Threads::number_of_threads() == 0 ||
1734         SafepointSynchronize::is_at_safepoint()) {
1735       // we're single threaded or at a safepoint - no locking needed
1736       id = get_jmethod_id_fetch_or_update(idnum, new_id, new_jmeths,
1737                                           &to_dealloc_id, &to_dealloc_jmeths);
1738     } else {
1739       MutexLocker ml(JmethodIdCreation_lock);
1740       id = get_jmethod_id_fetch_or_update(idnum, new_id, new_jmeths,
1741                                           &to_dealloc_id, &to_dealloc_jmeths);
1742     }
1743 
1744     // The lock has been dropped so we can free resources.
1745     // Free up either the old cache or the new cache if we allocated one.
1746     if (to_dealloc_jmeths != NULL) {
1747       FreeHeap(to_dealloc_jmeths);
1748     }
1749     // free up the new ID since it wasn't needed
1750     if (to_dealloc_id != NULL) {
1751       Method::destroy_jmethod_id(class_loader_data(), to_dealloc_id);
1752     }
1753   }
1754   return id;
1755 }
1756 
1757 // Figure out how many jmethodIDs haven't been allocated, and make
1758 // sure space for them is pre-allocated.  This makes getting all
1759 // method ids much, much faster with classes with more than 8
1760 // methods, and has a *substantial* effect on performance with jvmti
1761 // code that loads all jmethodIDs for all classes.
1762 void InstanceKlass::ensure_space_for_methodids(int start_offset) {
1763   int new_jmeths = 0;
1764   int length = methods()->length();
1765   for (int index = start_offset; index < length; index++) {
1766     Method* m = methods()->at(index);
1767     jmethodID id = m->find_jmethod_id_or_null();
1768     if (id == NULL) {
1769       new_jmeths++;
1770     }
1771   }
1772   if (new_jmeths != 0) {
1773     Method::ensure_jmethod_ids(class_loader_data(), new_jmeths);
1774   }
1775 }
1776 
1777 // Common code to fetch the jmethodID from the cache or update the
1778 // cache with the new jmethodID. This function should never do anything
1779 // that causes the caller to go to a safepoint or we can deadlock with
1780 // the VMThread or have cache consistency issues.
1781 //
1782 jmethodID InstanceKlass::get_jmethod_id_fetch_or_update(
1783             size_t idnum, jmethodID new_id,
1784             jmethodID* new_jmeths, jmethodID* to_dealloc_id_p,
1785             jmethodID** to_dealloc_jmeths_p) {
1786   assert(new_id != NULL, "sanity check");
1787   assert(to_dealloc_id_p != NULL, "sanity check");
1788   assert(to_dealloc_jmeths_p != NULL, "sanity check");
1789   assert(Threads::number_of_threads() == 0 ||
1790          SafepointSynchronize::is_at_safepoint() ||
1791          JmethodIdCreation_lock->owned_by_self(), "sanity check");
1792 
1793   // reacquire the cache - we are locked, single threaded or at a safepoint
1794   jmethodID* jmeths = methods_jmethod_ids_acquire();
1795   jmethodID  id     = NULL;
1796   size_t     length = 0;
1797 
1798   if (jmeths == NULL ||                         // no cache yet
1799       (length = (size_t)jmeths[0]) <= idnum) {  // cache is too short
1800     if (jmeths != NULL) {
1801       // copy any existing entries from the old cache
1802       for (size_t index = 0; index < length; index++) {
1803         new_jmeths[index+1] = jmeths[index+1];
1804       }
1805       *to_dealloc_jmeths_p = jmeths;  // save old cache for later delete
1806     }
1807     release_set_methods_jmethod_ids(jmeths = new_jmeths);
1808   } else {
1809     // fetch jmethodID (if any) from the existing cache
1810     id = jmeths[idnum+1];
1811     *to_dealloc_jmeths_p = new_jmeths;  // save new cache for later delete
1812   }
1813   if (id == NULL) {
1814     // No matching jmethodID in the existing cache or we have a new
1815     // cache or we just grew the cache. This cache write is done here
1816     // by the first thread to win the foot race because a jmethodID
1817     // needs to be unique once it is generally available.
1818     id = new_id;
1819 
1820     // The jmethodID cache can be read while unlocked so we have to
1821     // make sure the new jmethodID is complete before installing it
1822     // in the cache.
1823     OrderAccess::release_store_ptr(&jmeths[idnum+1], id);
1824   } else {
1825     *to_dealloc_id_p = new_id; // save new id for later delete
1826   }
1827   return id;
1828 }
1829 
1830 
1831 // Common code to get the jmethodID cache length and the jmethodID
1832 // value at index idnum if there is one.
1833 //
1834 void InstanceKlass::get_jmethod_id_length_value(jmethodID* cache,
1835        size_t idnum, size_t *length_p, jmethodID* id_p) {
1836   assert(cache != NULL, "sanity check");
1837   assert(length_p != NULL, "sanity check");
1838   assert(id_p != NULL, "sanity check");
1839 
1840   // cache size is stored in element[0], other elements offset by one
1841   *length_p = (size_t)cache[0];
1842   if (*length_p <= idnum) {  // cache is too short
1843     *id_p = NULL;
1844   } else {
1845     *id_p = cache[idnum+1];  // fetch jmethodID (if any)
1846   }
1847 }
1848 
1849 
1850 // Lookup a jmethodID, NULL if not found.  Do no blocking, no allocations, no handles
1851 jmethodID InstanceKlass::jmethod_id_or_null(Method* method) {
1852   size_t idnum = (size_t)method->method_idnum();
1853   jmethodID* jmeths = methods_jmethod_ids_acquire();
1854   size_t length;                                // length assigned as debugging crumb
1855   jmethodID id = NULL;
1856   if (jmeths != NULL &&                         // If there is a cache
1857       (length = (size_t)jmeths[0]) > idnum) {   // and if it is long enough,
1858     id = jmeths[idnum+1];                       // Look up the id (may be NULL)
1859   }
1860   return id;
1861 }
1862 
1863 inline DependencyContext InstanceKlass::dependencies() {
1864   DependencyContext dep_context(&_dep_context);
1865   return dep_context;
1866 }
1867 
1868 int InstanceKlass::mark_dependent_nmethods(KlassDepChange& changes) {
1869   return dependencies().mark_dependent_nmethods(changes);
1870 }
1871 
1872 void InstanceKlass::add_dependent_nmethod(nmethod* nm) {
1873   dependencies().add_dependent_nmethod(nm);
1874 }
1875 
1876 void InstanceKlass::remove_dependent_nmethod(nmethod* nm, bool delete_immediately) {
1877   dependencies().remove_dependent_nmethod(nm, delete_immediately);
1878 }
1879 
1880 #ifndef PRODUCT
1881 void InstanceKlass::print_dependent_nmethods(bool verbose) {
1882   dependencies().print_dependent_nmethods(verbose);
1883 }
1884 
1885 bool InstanceKlass::is_dependent_nmethod(nmethod* nm) {
1886   return dependencies().is_dependent_nmethod(nm);
1887 }
1888 #endif //PRODUCT
1889 
1890 void InstanceKlass::clean_weak_instanceklass_links(BoolObjectClosure* is_alive) {
1891   clean_implementors_list(is_alive);
1892   clean_method_data(is_alive);
1893 
1894   // Since GC iterates InstanceKlasses sequentially, it is safe to remove stale entries here.
1895   DependencyContext dep_context(&_dep_context);
1896   dep_context.expunge_stale_entries();
1897 }
1898 
1899 void InstanceKlass::clean_implementors_list(BoolObjectClosure* is_alive) {
1900   assert(class_loader_data()->is_alive(is_alive), "this klass should be live");
1901   if (is_interface()) {
1902     if (ClassUnloading) {
1903       Klass* impl = implementor();
1904       if (impl != NULL) {
1905         if (!impl->is_loader_alive(is_alive)) {
1906           // remove this guy
1907           Klass** klass = adr_implementor();
1908           assert(klass != NULL, "null klass");
1909           if (klass != NULL) {
1910             *klass = NULL;
1911           }
1912         }
1913       }
1914     }
1915   }
1916 }
1917 
1918 void InstanceKlass::clean_method_data(BoolObjectClosure* is_alive) {
1919   for (int m = 0; m < methods()->length(); m++) {
1920     MethodData* mdo = methods()->at(m)->method_data();
1921     if (mdo != NULL) {
1922       mdo->clean_method_data(is_alive);
1923     }
1924   }
1925 }
1926 
1927 bool InstanceKlass::supers_have_passed_fingerprint_checks() {
1928   if (java_super() != NULL && !java_super()->has_passed_fingerprint_check()) {
1929     ResourceMark rm;
1930     log_trace(class, fingerprint)("%s : super %s not fingerprinted", external_name(), java_super()->external_name());
1931     return false;
1932   }
1933 
1934   Array<Klass*>* local_interfaces = this->local_interfaces();
1935   if (local_interfaces != NULL) {
1936     int length = local_interfaces->length();
1937     for (int i = 0; i < length; i++) {
1938       InstanceKlass* intf = InstanceKlass::cast(local_interfaces->at(i));
1939       if (!intf->has_passed_fingerprint_check()) {
1940         ResourceMark rm;
1941         log_trace(class, fingerprint)("%s : interface %s not fingerprinted", external_name(), intf->external_name());
1942         return false;
1943       }
1944     }
1945   }
1946 
1947   return true;
1948 }
1949 
1950 bool InstanceKlass::should_store_fingerprint() {
1951 #if INCLUDE_AOT
1952   // We store the fingerprint into the InstanceKlass only in the following 2 cases:
1953   if (EnableJVMCI && !UseJVMCICompiler) {
1954     // (1) We are running AOT to generate a shared library.
1955     return true;
1956   }
1957   if (DumpSharedSpaces) {
1958     // (2) We are running -Xshare:dump to create a shared archive
1959     return true;
1960   }
1961 #endif
1962 
1963   // In all other cases we might set the _misc_has_passed_fingerprint_check bit,
1964   // but do not store the 64-bit fingerprint to save space.
1965   return false;
1966 }
1967 
1968 bool InstanceKlass::has_stored_fingerprint() const {
1969 #if INCLUDE_AOT
1970   return should_store_fingerprint() || is_shared();
1971 #else
1972   return false;
1973 #endif
1974 }
1975 
1976 uint64_t InstanceKlass::get_stored_fingerprint() const {
1977   address adr = adr_fingerprint();
1978   if (adr != NULL) {
1979     return (uint64_t)Bytes::get_native_u8(adr); // adr may not be 64-bit aligned
1980   }
1981   return 0;
1982 }
1983 
1984 void InstanceKlass::store_fingerprint(uint64_t fingerprint) {
1985   address adr = adr_fingerprint();
1986   if (adr != NULL) {
1987     Bytes::put_native_u8(adr, (u8)fingerprint); // adr may not be 64-bit aligned
1988 
1989     ResourceMark rm;
1990     log_trace(class, fingerprint)("stored as " PTR64_FORMAT " for class %s", fingerprint, external_name());
1991   }
1992 }
1993 
1994 static void remove_unshareable_in_class(Klass* k) {
1995   // remove klass's unshareable info
1996   k->remove_unshareable_info();
1997 }
1998 
1999 void InstanceKlass::remove_unshareable_info() {
2000   Klass::remove_unshareable_info();
2001   // Unlink the class
2002   if (is_linked()) {
2003     unlink_class();
2004   }
2005   init_implementor();
2006 
2007   constants()->remove_unshareable_info();
2008 
2009   assert(_dep_context == DependencyContext::EMPTY, "dependency context is not shareable");
2010 
2011   for (int i = 0; i < methods()->length(); i++) {
2012     Method* m = methods()->at(i);
2013     m->remove_unshareable_info();
2014   }
2015 
2016   // do array classes also.
2017   array_klasses_do(remove_unshareable_in_class);
2018 }
2019 
2020 static void restore_unshareable_in_class(Klass* k, TRAPS) {
2021   // Array classes have null protection domain.
2022   // --> see ArrayKlass::complete_create_array_klass()
2023   k->restore_unshareable_info(ClassLoaderData::the_null_class_loader_data(), Handle(), CHECK);
2024 }
2025 
2026 void InstanceKlass::restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS) {
2027   set_package(loader_data, CHECK);
2028   Klass::restore_unshareable_info(loader_data, protection_domain, CHECK);
2029 
2030   Array<Method*>* methods = this->methods();
2031   int num_methods = methods->length();
2032   for (int index2 = 0; index2 < num_methods; ++index2) {
2033     methodHandle m(THREAD, methods->at(index2));
2034     m->restore_unshareable_info(CHECK);
2035   }
2036   if (JvmtiExport::has_redefined_a_class()) {
2037     // Reinitialize vtable because RedefineClasses may have changed some
2038     // entries in this vtable for super classes so the CDS vtable might
2039     // point to old or obsolete entries.  RedefineClasses doesn't fix up
2040     // vtables in the shared system dictionary, only the main one.
2041     // It also redefines the itable too so fix that too.
2042     ResourceMark rm(THREAD);
2043     vtable().initialize_vtable(false, CHECK);
2044     itable().initialize_itable(false, CHECK);
2045   }
2046 
2047   // restore constant pool resolved references
2048   constants()->restore_unshareable_info(CHECK);
2049 
2050   array_klasses_do(restore_unshareable_in_class, CHECK);
2051 }
2052 
2053 // returns true IFF is_in_error_state() has been changed as a result of this call.
2054 bool InstanceKlass::check_sharing_error_state() {
2055   assert(DumpSharedSpaces, "should only be called during dumping");
2056   bool old_state = is_in_error_state();
2057 
2058   if (!is_in_error_state()) {
2059     bool bad = false;
2060     for (InstanceKlass* sup = java_super(); sup; sup = sup->java_super()) {
2061       if (sup->is_in_error_state()) {
2062         bad = true;
2063         break;
2064       }
2065     }
2066     if (!bad) {
2067       Array<Klass*>* interfaces = transitive_interfaces();
2068       for (int i = 0; i < interfaces->length(); i++) {
2069         Klass* iface = interfaces->at(i);
2070         if (InstanceKlass::cast(iface)->is_in_error_state()) {
2071           bad = true;
2072           break;
2073         }
2074       }
2075     }
2076 
2077     if (bad) {
2078       set_in_error_state();
2079     }
2080   }
2081 
2082   return (old_state != is_in_error_state());
2083 }
2084 
2085 #if INCLUDE_JVMTI
2086 static void clear_all_breakpoints(Method* m) {
2087   m->clear_all_breakpoints();
2088 }
2089 #endif
2090 
2091 void InstanceKlass::notify_unload_class(InstanceKlass* ik) {
2092   // notify the debugger
2093   if (JvmtiExport::should_post_class_unload()) {
2094     JvmtiExport::post_class_unload(ik);
2095   }
2096 
2097   // notify ClassLoadingService of class unload
2098   ClassLoadingService::notify_class_unloaded(ik);
2099 }
2100 
2101 void InstanceKlass::release_C_heap_structures(InstanceKlass* ik) {
2102   // Clean up C heap
2103   ik->release_C_heap_structures();
2104   ik->constants()->release_C_heap_structures();
2105 }
2106 
2107 void InstanceKlass::release_C_heap_structures() {
2108   // Can't release the constant pool here because the constant pool can be
2109   // deallocated separately from the InstanceKlass for default methods and
2110   // redefine classes.
2111 
2112   // Deallocate oop map cache
2113   if (_oop_map_cache != NULL) {
2114     delete _oop_map_cache;
2115     _oop_map_cache = NULL;
2116   }
2117 
2118   // Deallocate JNI identifiers for jfieldIDs
2119   JNIid::deallocate(jni_ids());
2120   set_jni_ids(NULL);
2121 
2122   jmethodID* jmeths = methods_jmethod_ids_acquire();
2123   if (jmeths != (jmethodID*)NULL) {
2124     release_set_methods_jmethod_ids(NULL);
2125     FreeHeap(jmeths);
2126   }
2127 
2128   // Deallocate MemberNameTable
2129   {
2130     Mutex* lock_or_null = SafepointSynchronize::is_at_safepoint() ? NULL : MemberNameTable_lock;
2131     MutexLockerEx ml(lock_or_null, Mutex::_no_safepoint_check_flag);
2132     MemberNameTable* mnt = member_names();
2133     if (mnt != NULL) {
2134       delete mnt;
2135       set_member_names(NULL);
2136     }
2137   }
2138 
2139   // Release dependencies.
2140   // It is desirable to use DC::remove_all_dependents() here, but, unfortunately,
2141   // it is not safe (see JDK-8143408). The problem is that the klass dependency
2142   // context can contain live dependencies, since there's a race between nmethod &
2143   // klass unloading. If the klass is dead when nmethod unloading happens, relevant
2144   // dependencies aren't removed from the context associated with the class (see
2145   // nmethod::flush_dependencies). It ends up during klass unloading as seemingly
2146   // live dependencies pointing to unloaded nmethods and causes a crash in
2147   // DC::remove_all_dependents() when it touches unloaded nmethod.
2148   dependencies().wipe();
2149 
2150 #if INCLUDE_JVMTI
2151   // Deallocate breakpoint records
2152   if (breakpoints() != 0x0) {
2153     methods_do(clear_all_breakpoints);
2154     assert(breakpoints() == 0x0, "should have cleared breakpoints");
2155   }
2156 
2157   // deallocate the cached class file
2158   if (_cached_class_file != NULL && !MetaspaceShared::is_in_shared_space(_cached_class_file)) {
2159     os::free(_cached_class_file);
2160     _cached_class_file = NULL;
2161   }
2162 #endif
2163 
2164   // Decrement symbol reference counts associated with the unloaded class.
2165   if (_name != NULL) _name->decrement_refcount();
2166   // unreference array name derived from this class name (arrays of an unloaded
2167   // class can't be referenced anymore).
2168   if (_array_name != NULL)  _array_name->decrement_refcount();
2169   if (_source_debug_extension != NULL) FREE_C_HEAP_ARRAY(char, _source_debug_extension);
2170 
2171   assert(_total_instanceKlass_count >= 1, "Sanity check");
2172   Atomic::dec(&_total_instanceKlass_count);
2173 }
2174 
2175 void InstanceKlass::set_source_debug_extension(const char* array, int length) {
2176   if (array == NULL) {
2177     _source_debug_extension = NULL;
2178   } else {
2179     // Adding one to the attribute length in order to store a null terminator
2180     // character could cause an overflow because the attribute length is
2181     // already coded with an u4 in the classfile, but in practice, it's
2182     // unlikely to happen.
2183     assert((length+1) > length, "Overflow checking");
2184     char* sde = NEW_C_HEAP_ARRAY(char, (length + 1), mtClass);
2185     for (int i = 0; i < length; i++) {
2186       sde[i] = array[i];
2187     }
2188     sde[length] = '\0';
2189     _source_debug_extension = sde;
2190   }
2191 }
2192 
2193 address InstanceKlass::static_field_addr(int offset) {
2194   return (address)(offset + InstanceMirrorKlass::offset_of_static_fields() + cast_from_oop<intptr_t>(java_mirror()));
2195 }
2196 
2197 
2198 const char* InstanceKlass::signature_name() const {
2199   int hash_len = 0;
2200   char hash_buf[40];
2201 
2202   // If this is an anonymous class, append a hash to make the name unique
2203   if (is_anonymous()) {
2204     intptr_t hash = (java_mirror() != NULL) ? java_mirror()->identity_hash() : 0;
2205     jio_snprintf(hash_buf, sizeof(hash_buf), "/" UINTX_FORMAT, (uintx)hash);
2206     hash_len = (int)strlen(hash_buf);
2207   }
2208 
2209   // Get the internal name as a c string
2210   const char* src = (const char*) (name()->as_C_string());
2211   const int src_length = (int)strlen(src);
2212 
2213   char* dest = NEW_RESOURCE_ARRAY(char, src_length + hash_len + 3);
2214 
2215   // Add L as type indicator
2216   int dest_index = 0;
2217   dest[dest_index++] = 'L';
2218 
2219   // Add the actual class name
2220   for (int src_index = 0; src_index < src_length; ) {
2221     dest[dest_index++] = src[src_index++];
2222   }
2223 
2224   // If we have a hash, append it
2225   for (int hash_index = 0; hash_index < hash_len; ) {
2226     dest[dest_index++] = hash_buf[hash_index++];
2227   }
2228 
2229   // Add the semicolon and the NULL
2230   dest[dest_index++] = ';';
2231   dest[dest_index] = '\0';
2232   return dest;
2233 }
2234 
2235 // Used to obtain the package name from a fully qualified class name.
2236 Symbol* InstanceKlass::package_from_name(const Symbol* name, TRAPS) {
2237   if (name == NULL) {
2238     return NULL;
2239   } else {
2240     if (name->utf8_length() <= 0) {
2241       return NULL;
2242     }
2243     ResourceMark rm;
2244     const char* package_name = ClassLoader::package_from_name((const char*) name->as_C_string());
2245     if (package_name == NULL) {
2246       return NULL;
2247     }
2248     Symbol* pkg_name = SymbolTable::new_symbol(package_name, THREAD);
2249     return pkg_name;
2250   }
2251 }
2252 
2253 ModuleEntry* InstanceKlass::module() const {
2254   if (!in_unnamed_package()) {
2255     return _package_entry->module();
2256   }
2257   const Klass* host = host_klass();
2258   if (host == NULL) {
2259     return class_loader_data()->unnamed_module();
2260   }
2261   return host->class_loader_data()->unnamed_module();
2262 }
2263 
2264 void InstanceKlass::set_package(ClassLoaderData* loader_data, TRAPS) {
2265 
2266   // ensure java/ packages only loaded by boot or platform builtin loaders
2267   Handle class_loader(THREAD, loader_data->class_loader());
2268   check_prohibited_package(name(), class_loader, CHECK);
2269 
2270   TempNewSymbol pkg_name = package_from_name(name(), CHECK);
2271 
2272   if (pkg_name != NULL && loader_data != NULL) {
2273 
2274     // Find in class loader's package entry table.
2275     _package_entry = loader_data->packages()->lookup_only(pkg_name);
2276 
2277     // If the package name is not found in the loader's package
2278     // entry table, it is an indication that the package has not
2279     // been defined. Consider it defined within the unnamed module.
2280     if (_package_entry == NULL) {
2281       ResourceMark rm;
2282 
2283       if (!ModuleEntryTable::javabase_defined()) {
2284         // Before java.base is defined during bootstrapping, define all packages in
2285         // the java.base module.  If a non-java.base package is erroneously placed
2286         // in the java.base module it will be caught later when java.base
2287         // is defined by ModuleEntryTable::verify_javabase_packages check.
2288         assert(ModuleEntryTable::javabase_moduleEntry() != NULL, JAVA_BASE_NAME " module is NULL");
2289         _package_entry = loader_data->packages()->lookup(pkg_name, ModuleEntryTable::javabase_moduleEntry());
2290       } else {
2291         assert(loader_data->unnamed_module() != NULL, "unnamed module is NULL");
2292         _package_entry = loader_data->packages()->lookup(pkg_name,
2293                                                          loader_data->unnamed_module());
2294       }
2295 
2296       // A package should have been successfully created
2297       assert(_package_entry != NULL, "Package entry for class %s not found, loader %s",
2298              name()->as_C_string(), loader_data->loader_name());
2299     }
2300 
2301     if (log_is_enabled(Debug, modules)) {
2302       ResourceMark rm;
2303       ModuleEntry* m = _package_entry->module();
2304       log_trace(modules)("Setting package: class: %s, package: %s, loader: %s, module: %s",
2305                          external_name(),
2306                          pkg_name->as_C_string(),
2307                          loader_data->loader_name(),
2308                          (m->is_named() ? m->name()->as_C_string() : UNNAMED_MODULE));
2309     }
2310   } else {
2311     ResourceMark rm;
2312     log_trace(modules)("Setting package: class: %s, package: unnamed, loader: %s, module: %s",
2313                        external_name(),
2314                        (loader_data != NULL) ? loader_data->loader_name() : "NULL",
2315                        UNNAMED_MODULE);
2316   }
2317 }
2318 
2319 
2320 // different versions of is_same_class_package
2321 
2322 bool InstanceKlass::is_same_class_package(const Klass* class2) const {
2323   oop classloader1 = this->class_loader();
2324   PackageEntry* classpkg1 = this->package();
2325   if (class2->is_objArray_klass()) {
2326     class2 = ObjArrayKlass::cast(class2)->bottom_klass();
2327   }
2328 
2329   oop classloader2;
2330   PackageEntry* classpkg2;
2331   if (class2->is_instance_klass()) {
2332     classloader2 = class2->class_loader();
2333     classpkg2 = class2->package();
2334   } else {
2335     assert(class2->is_typeArray_klass(), "should be type array");
2336     classloader2 = NULL;
2337     classpkg2 = NULL;
2338   }
2339 
2340   // Same package is determined by comparing class loader
2341   // and package entries. Both must be the same. This rule
2342   // applies even to classes that are defined in the unnamed
2343   // package, they still must have the same class loader.
2344   if ((classloader1 == classloader2) && (classpkg1 == classpkg2)) {
2345     return true;
2346   }
2347 
2348   return false;
2349 }
2350 
2351 bool InstanceKlass::is_same_class_package(oop other_class_loader,
2352                                           const Symbol* other_class_name) const {
2353   oop this_class_loader = class_loader();
2354   const Symbol* const this_class_name = name();
2355 
2356   return InstanceKlass::is_same_class_package(this_class_loader,
2357                                              this_class_name,
2358                                              other_class_loader,
2359                                              other_class_name);
2360 }
2361 
2362 // return true if two classes are in the same package, classloader
2363 // and classname information is enough to determine a class's package
2364 bool InstanceKlass::is_same_class_package(oop class_loader1, const Symbol* class_name1,
2365                                           oop class_loader2, const Symbol* class_name2) {
2366   if (class_loader1 != class_loader2) {
2367     return false;
2368   } else if (class_name1 == class_name2) {
2369     return true;
2370   } else {
2371     ResourceMark rm;
2372 
2373     bool bad_class_name = false;
2374     const char* name1 = ClassLoader::package_from_name((const char*) class_name1->as_C_string(), &bad_class_name);
2375     if (bad_class_name) {
2376       return false;
2377     }
2378 
2379     const char* name2 = ClassLoader::package_from_name((const char*) class_name2->as_C_string(), &bad_class_name);
2380     if (bad_class_name) {
2381       return false;
2382     }
2383 
2384     if ((name1 == NULL) || (name2 == NULL)) {
2385       // One of the two doesn't have a package.  Only return true
2386       // if the other one also doesn't have a package.
2387       return name1 == name2;
2388     }
2389 
2390     // Check that package is identical
2391     return (strcmp(name1, name2) == 0);
2392   }
2393 }
2394 
2395 // Returns true iff super_method can be overridden by a method in targetclassname
2396 // See JLS 3rd edition 8.4.6.1
2397 // Assumes name-signature match
2398 // "this" is InstanceKlass of super_method which must exist
2399 // note that the InstanceKlass of the method in the targetclassname has not always been created yet
2400 bool InstanceKlass::is_override(const methodHandle& super_method, Handle targetclassloader, Symbol* targetclassname, TRAPS) {
2401    // Private methods can not be overridden
2402    if (super_method->is_private()) {
2403      return false;
2404    }
2405    // If super method is accessible, then override
2406    if ((super_method->is_protected()) ||
2407        (super_method->is_public())) {
2408      return true;
2409    }
2410    // Package-private methods are not inherited outside of package
2411    assert(super_method->is_package_private(), "must be package private");
2412    return(is_same_class_package(targetclassloader(), targetclassname));
2413 }
2414 
2415 // Only boot and platform class loaders can define classes in "java/" packages.
2416 void InstanceKlass::check_prohibited_package(Symbol* class_name,
2417                                              Handle class_loader,
2418                                              TRAPS) {
2419   if (!class_loader.is_null() &&
2420       !SystemDictionary::is_platform_class_loader(class_loader()) &&
2421       class_name != NULL) {
2422     ResourceMark rm(THREAD);
2423     char* name = class_name->as_C_string();
2424     if (strncmp(name, JAVAPKG, JAVAPKG_LEN) == 0 && name[JAVAPKG_LEN] == '/') {
2425       TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK);
2426       assert(pkg_name != NULL, "Error in parsing package name starting with 'java/'");
2427       name = pkg_name->as_C_string();
2428       const char* class_loader_name = SystemDictionary::loader_name(class_loader());
2429       StringUtils::replace_no_expand(name, "/", ".");
2430       const char* msg_text1 = "Class loader (instance of): ";
2431       const char* msg_text2 = " tried to load prohibited package name: ";
2432       size_t len = strlen(msg_text1) + strlen(class_loader_name) + strlen(msg_text2) + strlen(name) + 1;
2433       char* message = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, len);
2434       jio_snprintf(message, len, "%s%s%s%s", msg_text1, class_loader_name, msg_text2, name);
2435       THROW_MSG(vmSymbols::java_lang_SecurityException(), message);
2436     }
2437   }
2438   return;
2439 }
2440 
2441 // tell if two classes have the same enclosing class (at package level)
2442 bool InstanceKlass::is_same_package_member(const Klass* class2, TRAPS) const {
2443   if (class2 == this) return true;
2444   if (!class2->is_instance_klass())  return false;
2445 
2446   // must be in same package before we try anything else
2447   if (!is_same_class_package(class2))
2448     return false;
2449 
2450   // As long as there is an outer_this.getEnclosingClass,
2451   // shift the search outward.
2452   const InstanceKlass* outer_this = this;
2453   for (;;) {
2454     // As we walk along, look for equalities between outer_this and class2.
2455     // Eventually, the walks will terminate as outer_this stops
2456     // at the top-level class around the original class.
2457     bool ignore_inner_is_member;
2458     const Klass* next = outer_this->compute_enclosing_class(&ignore_inner_is_member,
2459                                                             CHECK_false);
2460     if (next == NULL)  break;
2461     if (next == class2)  return true;
2462     outer_this = InstanceKlass::cast(next);
2463   }
2464 
2465   // Now do the same for class2.
2466   const InstanceKlass* outer2 = InstanceKlass::cast(class2);
2467   for (;;) {
2468     bool ignore_inner_is_member;
2469     Klass* next = outer2->compute_enclosing_class(&ignore_inner_is_member,
2470                                                     CHECK_false);
2471     if (next == NULL)  break;
2472     // Might as well check the new outer against all available values.
2473     if (next == this)  return true;
2474     if (next == outer_this)  return true;
2475     outer2 = InstanceKlass::cast(next);
2476   }
2477 
2478   // If by this point we have not found an equality between the
2479   // two classes, we know they are in separate package members.
2480   return false;
2481 }
2482 
2483 bool InstanceKlass::find_inner_classes_attr(int* ooff, int* noff, TRAPS) const {
2484   constantPoolHandle i_cp(THREAD, constants());
2485   for (InnerClassesIterator iter(this); !iter.done(); iter.next()) {
2486     int ioff = iter.inner_class_info_index();
2487     if (ioff != 0) {
2488       // Check to see if the name matches the class we're looking for
2489       // before attempting to find the class.
2490       if (i_cp->klass_name_at_matches(this, ioff)) {
2491         Klass* inner_klass = i_cp->klass_at(ioff, CHECK_false);
2492         if (this == inner_klass) {
2493           *ooff = iter.outer_class_info_index();
2494           *noff = iter.inner_name_index();
2495           return true;
2496         }
2497       }
2498     }
2499   }
2500   return false;
2501 }
2502 
2503 InstanceKlass* InstanceKlass::compute_enclosing_class(bool* inner_is_member, TRAPS) const {
2504   InstanceKlass* outer_klass = NULL;
2505   *inner_is_member = false;
2506   int ooff = 0, noff = 0;
2507   bool has_inner_classes_attr = find_inner_classes_attr(&ooff, &noff, THREAD);
2508   if (has_inner_classes_attr) {
2509     constantPoolHandle i_cp(THREAD, constants());
2510     if (ooff != 0) {
2511       Klass* ok = i_cp->klass_at(ooff, CHECK_NULL);
2512       outer_klass = InstanceKlass::cast(ok);
2513       *inner_is_member = true;
2514     }
2515     if (NULL == outer_klass) {
2516       // It may be anonymous; try for that.
2517       int encl_method_class_idx = enclosing_method_class_index();
2518       if (encl_method_class_idx != 0) {
2519         Klass* ok = i_cp->klass_at(encl_method_class_idx, CHECK_NULL);
2520         outer_klass = InstanceKlass::cast(ok);
2521         *inner_is_member = false;
2522       }
2523     }
2524   }
2525 
2526   // If no inner class attribute found for this class.
2527   if (NULL == outer_klass) return NULL;
2528 
2529   // Throws an exception if outer klass has not declared k as an inner klass
2530   // We need evidence that each klass knows about the other, or else
2531   // the system could allow a spoof of an inner class to gain access rights.
2532   Reflection::check_for_inner_class(outer_klass, this, *inner_is_member, CHECK_NULL);
2533   return outer_klass;
2534 }
2535 
2536 jint InstanceKlass::compute_modifier_flags(TRAPS) const {
2537   jint access = access_flags().as_int();
2538 
2539   // But check if it happens to be member class.
2540   InnerClassesIterator iter(this);
2541   for (; !iter.done(); iter.next()) {
2542     int ioff = iter.inner_class_info_index();
2543     // Inner class attribute can be zero, skip it.
2544     // Strange but true:  JVM spec. allows null inner class refs.
2545     if (ioff == 0) continue;
2546 
2547     // only look at classes that are already loaded
2548     // since we are looking for the flags for our self.
2549     Symbol* inner_name = constants()->klass_name_at(ioff);
2550     if (name() == inner_name) {
2551       // This is really a member class.
2552       access = iter.inner_access_flags();
2553       break;
2554     }
2555   }
2556   // Remember to strip ACC_SUPER bit
2557   return (access & (~JVM_ACC_SUPER)) & JVM_ACC_WRITTEN_FLAGS;
2558 }
2559 
2560 jint InstanceKlass::jvmti_class_status() const {
2561   jint result = 0;
2562 
2563   if (is_linked()) {
2564     result |= JVMTI_CLASS_STATUS_VERIFIED | JVMTI_CLASS_STATUS_PREPARED;
2565   }
2566 
2567   if (is_initialized()) {
2568     assert(is_linked(), "Class status is not consistent");
2569     result |= JVMTI_CLASS_STATUS_INITIALIZED;
2570   }
2571   if (is_in_error_state()) {
2572     result |= JVMTI_CLASS_STATUS_ERROR;
2573   }
2574   return result;
2575 }
2576 
2577 Method* InstanceKlass::method_at_itable(Klass* holder, int index, TRAPS) {
2578   itableOffsetEntry* ioe = (itableOffsetEntry*)start_of_itable();
2579   int method_table_offset_in_words = ioe->offset()/wordSize;
2580   int nof_interfaces = (method_table_offset_in_words - itable_offset_in_words())
2581                        / itableOffsetEntry::size();
2582 
2583   for (int cnt = 0 ; ; cnt ++, ioe ++) {
2584     // If the interface isn't implemented by the receiver class,
2585     // the VM should throw IncompatibleClassChangeError.
2586     if (cnt >= nof_interfaces) {
2587       THROW_NULL(vmSymbols::java_lang_IncompatibleClassChangeError());
2588     }
2589 
2590     Klass* ik = ioe->interface_klass();
2591     if (ik == holder) break;
2592   }
2593 
2594   itableMethodEntry* ime = ioe->first_method_entry(this);
2595   Method* m = ime[index].method();
2596   if (m == NULL) {
2597     THROW_NULL(vmSymbols::java_lang_AbstractMethodError());
2598   }
2599   return m;
2600 }
2601 
2602 
2603 #if INCLUDE_JVMTI
2604 // update default_methods for redefineclasses for methods that are
2605 // not yet in the vtable due to concurrent subclass define and superinterface
2606 // redefinition
2607 // Note: those in the vtable, should have been updated via adjust_method_entries
2608 void InstanceKlass::adjust_default_methods(InstanceKlass* holder, bool* trace_name_printed) {
2609   // search the default_methods for uses of either obsolete or EMCP methods
2610   if (default_methods() != NULL) {
2611     for (int index = 0; index < default_methods()->length(); index ++) {
2612       Method* old_method = default_methods()->at(index);
2613       if (old_method == NULL || old_method->method_holder() != holder || !old_method->is_old()) {
2614         continue; // skip uninteresting entries
2615       }
2616       assert(!old_method->is_deleted(), "default methods may not be deleted");
2617 
2618       Method* new_method = holder->method_with_idnum(old_method->orig_method_idnum());
2619 
2620       assert(new_method != NULL, "method_with_idnum() should not be NULL");
2621       assert(old_method != new_method, "sanity check");
2622 
2623       default_methods()->at_put(index, new_method);
2624       if (log_is_enabled(Info, redefine, class, update)) {
2625         ResourceMark rm;
2626         if (!(*trace_name_printed)) {
2627           log_info(redefine, class, update)
2628             ("adjust: klassname=%s default methods from name=%s",
2629              external_name(), old_method->method_holder()->external_name());
2630           *trace_name_printed = true;
2631         }
2632         log_debug(redefine, class, update, vtables)
2633           ("default method update: %s(%s) ",
2634            new_method->name()->as_C_string(), new_method->signature()->as_C_string());
2635       }
2636     }
2637   }
2638 }
2639 #endif // INCLUDE_JVMTI
2640 
2641 // On-stack replacement stuff
2642 void InstanceKlass::add_osr_nmethod(nmethod* n) {
2643   // only one compilation can be active
2644   {
2645     // This is a short non-blocking critical region, so the no safepoint check is ok.
2646     MutexLockerEx ml(OsrList_lock, Mutex::_no_safepoint_check_flag);
2647     assert(n->is_osr_method(), "wrong kind of nmethod");
2648     n->set_osr_link(osr_nmethods_head());
2649     set_osr_nmethods_head(n);
2650     // Raise the highest osr level if necessary
2651     if (TieredCompilation) {
2652       Method* m = n->method();
2653       m->set_highest_osr_comp_level(MAX2(m->highest_osr_comp_level(), n->comp_level()));
2654     }
2655   }
2656 
2657   // Get rid of the osr methods for the same bci that have lower levels.
2658   if (TieredCompilation) {
2659     for (int l = CompLevel_limited_profile; l < n->comp_level(); l++) {
2660       nmethod *inv = lookup_osr_nmethod(n->method(), n->osr_entry_bci(), l, true);
2661       if (inv != NULL && inv->is_in_use()) {
2662         inv->make_not_entrant();
2663       }
2664     }
2665   }
2666 }
2667 
2668 // Remove osr nmethod from the list. Return true if found and removed.
2669 bool InstanceKlass::remove_osr_nmethod(nmethod* n) {
2670   // This is a short non-blocking critical region, so the no safepoint check is ok.
2671   MutexLockerEx ml(OsrList_lock, Mutex::_no_safepoint_check_flag);
2672   assert(n->is_osr_method(), "wrong kind of nmethod");
2673   nmethod* last = NULL;
2674   nmethod* cur  = osr_nmethods_head();
2675   int max_level = CompLevel_none;  // Find the max comp level excluding n
2676   Method* m = n->method();
2677   // Search for match
2678   bool found = false;
2679   while(cur != NULL && cur != n) {
2680     if (TieredCompilation && m == cur->method()) {
2681       // Find max level before n
2682       max_level = MAX2(max_level, cur->comp_level());
2683     }
2684     last = cur;
2685     cur = cur->osr_link();
2686   }
2687   nmethod* next = NULL;
2688   if (cur == n) {
2689     found = true;
2690     next = cur->osr_link();
2691     if (last == NULL) {
2692       // Remove first element
2693       set_osr_nmethods_head(next);
2694     } else {
2695       last->set_osr_link(next);
2696     }
2697   }
2698   n->set_osr_link(NULL);
2699   if (TieredCompilation) {
2700     cur = next;
2701     while (cur != NULL) {
2702       // Find max level after n
2703       if (m == cur->method()) {
2704         max_level = MAX2(max_level, cur->comp_level());
2705       }
2706       cur = cur->osr_link();
2707     }
2708     m->set_highest_osr_comp_level(max_level);
2709   }
2710   return found;
2711 }
2712 
2713 int InstanceKlass::mark_osr_nmethods(const Method* m) {
2714   // This is a short non-blocking critical region, so the no safepoint check is ok.
2715   MutexLockerEx ml(OsrList_lock, Mutex::_no_safepoint_check_flag);
2716   nmethod* osr = osr_nmethods_head();
2717   int found = 0;
2718   while (osr != NULL) {
2719     assert(osr->is_osr_method(), "wrong kind of nmethod found in chain");
2720     if (osr->method() == m) {
2721       osr->mark_for_deoptimization();
2722       found++;
2723     }
2724     osr = osr->osr_link();
2725   }
2726   return found;
2727 }
2728 
2729 nmethod* InstanceKlass::lookup_osr_nmethod(const Method* m, int bci, int comp_level, bool match_level) const {
2730   // This is a short non-blocking critical region, so the no safepoint check is ok.
2731   MutexLockerEx ml(OsrList_lock, Mutex::_no_safepoint_check_flag);
2732   nmethod* osr = osr_nmethods_head();
2733   nmethod* best = NULL;
2734   while (osr != NULL) {
2735     assert(osr->is_osr_method(), "wrong kind of nmethod found in chain");
2736     // There can be a time when a c1 osr method exists but we are waiting
2737     // for a c2 version. When c2 completes its osr nmethod we will trash
2738     // the c1 version and only be able to find the c2 version. However
2739     // while we overflow in the c1 code at back branches we don't want to
2740     // try and switch to the same code as we are already running
2741 
2742     if (osr->method() == m &&
2743         (bci == InvocationEntryBci || osr->osr_entry_bci() == bci)) {
2744       if (match_level) {
2745         if (osr->comp_level() == comp_level) {
2746           // Found a match - return it.
2747           return osr;
2748         }
2749       } else {
2750         if (best == NULL || (osr->comp_level() > best->comp_level())) {
2751           if (osr->comp_level() == CompLevel_highest_tier) {
2752             // Found the best possible - return it.
2753             return osr;
2754           }
2755           best = osr;
2756         }
2757       }
2758     }
2759     osr = osr->osr_link();
2760   }
2761   if (best != NULL && best->comp_level() >= comp_level && match_level == false) {
2762     return best;
2763   }
2764   return NULL;
2765 }
2766 
2767 oop InstanceKlass::add_member_name(Handle mem_name, bool intern) {
2768   jweak mem_name_wref = JNIHandles::make_weak_global(mem_name);
2769   MutexLocker ml(MemberNameTable_lock);
2770   DEBUG_ONLY(NoSafepointVerifier nsv);
2771 
2772   // Check if method has been redefined while taking out MemberNameTable_lock, if so
2773   // return false.  We cannot cache obsolete methods. They will crash when the function
2774   // is called!
2775   Method* method = (Method*)java_lang_invoke_MemberName::vmtarget(mem_name());
2776   if (method->is_obsolete()) {
2777     return NULL;
2778   } else if (method->is_old()) {
2779     // Replace method with redefined version
2780     java_lang_invoke_MemberName::set_vmtarget(mem_name(), method_with_idnum(method->method_idnum()));
2781   }
2782 
2783   if (_member_names == NULL) {
2784     _member_names = new (ResourceObj::C_HEAP, mtClass) MemberNameTable(idnum_allocated_count());
2785   }
2786   if (intern) {
2787     return _member_names->find_or_add_member_name(mem_name_wref);
2788   } else {
2789     return _member_names->add_member_name(mem_name_wref);
2790   }
2791 }
2792 
2793 // -----------------------------------------------------------------------------------------------------
2794 // Printing
2795 
2796 #ifndef PRODUCT
2797 
2798 #define BULLET  " - "
2799 
2800 static const char* state_names[] = {
2801   "allocated", "loaded", "linked", "being_initialized", "fully_initialized", "initialization_error"
2802 };
2803 
2804 static void print_vtable(intptr_t* start, int len, outputStream* st) {
2805   for (int i = 0; i < len; i++) {
2806     intptr_t e = start[i];
2807     st->print("%d : " INTPTR_FORMAT, i, e);
2808     if (e != 0 && ((Metadata*)e)->is_metaspace_object()) {
2809       st->print(" ");
2810       ((Metadata*)e)->print_value_on(st);
2811     }
2812     st->cr();
2813   }
2814 }
2815 
2816 static void print_vtable(vtableEntry* start, int len, outputStream* st) {
2817   return print_vtable(reinterpret_cast<intptr_t*>(start), len, st);
2818 }
2819 
2820 void InstanceKlass::print_on(outputStream* st) const {
2821   assert(is_klass(), "must be klass");
2822   Klass::print_on(st);
2823 
2824   st->print(BULLET"instance size:     %d", size_helper());                        st->cr();
2825   st->print(BULLET"klass size:        %d", size());                               st->cr();
2826   st->print(BULLET"access:            "); access_flags().print_on(st);            st->cr();
2827   st->print(BULLET"state:             "); st->print_cr("%s", state_names[_init_state]);
2828   st->print(BULLET"name:              "); name()->print_value_on(st);             st->cr();
2829   st->print(BULLET"super:             "); super()->print_value_on_maybe_null(st); st->cr();
2830   st->print(BULLET"sub:               ");
2831   Klass* sub = subklass();
2832   int n;
2833   for (n = 0; sub != NULL; n++, sub = sub->next_sibling()) {
2834     if (n < MaxSubklassPrintSize) {
2835       sub->print_value_on(st);
2836       st->print("   ");
2837     }
2838   }
2839   if (n >= MaxSubklassPrintSize) st->print("(" INTX_FORMAT " more klasses...)", n - MaxSubklassPrintSize);
2840   st->cr();
2841 
2842   if (is_interface()) {
2843     st->print_cr(BULLET"nof implementors:  %d", nof_implementors());
2844     if (nof_implementors() == 1) {
2845       st->print_cr(BULLET"implementor:    ");
2846       st->print("   ");
2847       implementor()->print_value_on(st);
2848       st->cr();
2849     }
2850   }
2851 
2852   st->print(BULLET"arrays:            "); array_klasses()->print_value_on_maybe_null(st); st->cr();
2853   st->print(BULLET"methods:           "); methods()->print_value_on(st);                  st->cr();
2854   if (Verbose || WizardMode) {
2855     Array<Method*>* method_array = methods();
2856     for (int i = 0; i < method_array->length(); i++) {
2857       st->print("%d : ", i); method_array->at(i)->print_value(); st->cr();
2858     }
2859   }
2860   st->print(BULLET"method ordering:   "); method_ordering()->print_value_on(st);      st->cr();
2861   st->print(BULLET"default_methods:   "); default_methods()->print_value_on(st);      st->cr();
2862   if (Verbose && default_methods() != NULL) {
2863     Array<Method*>* method_array = default_methods();
2864     for (int i = 0; i < method_array->length(); i++) {
2865       st->print("%d : ", i); method_array->at(i)->print_value(); st->cr();
2866     }
2867   }
2868   if (default_vtable_indices() != NULL) {
2869     st->print(BULLET"default vtable indices:   "); default_vtable_indices()->print_value_on(st);       st->cr();
2870   }
2871   st->print(BULLET"local interfaces:  "); local_interfaces()->print_value_on(st);      st->cr();
2872   st->print(BULLET"trans. interfaces: "); transitive_interfaces()->print_value_on(st); st->cr();
2873   st->print(BULLET"constants:         "); constants()->print_value_on(st);         st->cr();
2874   if (class_loader_data() != NULL) {
2875     st->print(BULLET"class loader data:  ");
2876     class_loader_data()->print_value_on(st);
2877     st->cr();
2878   }
2879   st->print(BULLET"host class:        "); host_klass()->print_value_on_maybe_null(st); st->cr();
2880   if (source_file_name() != NULL) {
2881     st->print(BULLET"source file:       ");
2882     source_file_name()->print_value_on(st);
2883     st->cr();
2884   }
2885   if (source_debug_extension() != NULL) {
2886     st->print(BULLET"source debug extension:       ");
2887     st->print("%s", source_debug_extension());
2888     st->cr();
2889   }
2890   st->print(BULLET"class annotations:       "); class_annotations()->print_value_on(st); st->cr();
2891   st->print(BULLET"class type annotations:  "); class_type_annotations()->print_value_on(st); st->cr();
2892   st->print(BULLET"field annotations:       "); fields_annotations()->print_value_on(st); st->cr();
2893   st->print(BULLET"field type annotations:  "); fields_type_annotations()->print_value_on(st); st->cr();
2894   {
2895     bool have_pv = false;
2896     // previous versions are linked together through the InstanceKlass
2897     for (InstanceKlass* pv_node = previous_versions();
2898          pv_node != NULL;
2899          pv_node = pv_node->previous_versions()) {
2900       if (!have_pv)
2901         st->print(BULLET"previous version:  ");
2902       have_pv = true;
2903       pv_node->constants()->print_value_on(st);
2904     }
2905     if (have_pv) st->cr();
2906   }
2907 
2908   if (generic_signature() != NULL) {
2909     st->print(BULLET"generic signature: ");
2910     generic_signature()->print_value_on(st);
2911     st->cr();
2912   }
2913   st->print(BULLET"inner classes:     "); inner_classes()->print_value_on(st);     st->cr();
2914   st->print(BULLET"java mirror:       "); java_mirror()->print_value_on(st);       st->cr();
2915   st->print(BULLET"vtable length      %d  (start addr: " INTPTR_FORMAT ")", vtable_length(), p2i(start_of_vtable())); st->cr();
2916   if (vtable_length() > 0 && (Verbose || WizardMode))  print_vtable(start_of_vtable(), vtable_length(), st);
2917   st->print(BULLET"itable length      %d (start addr: " INTPTR_FORMAT ")", itable_length(), p2i(start_of_itable())); st->cr();
2918   if (itable_length() > 0 && (Verbose || WizardMode))  print_vtable(start_of_itable(), itable_length(), st);
2919   st->print_cr(BULLET"---- static fields (%d words):", static_field_size());
2920   FieldPrinter print_static_field(st);
2921   ((InstanceKlass*)this)->do_local_static_fields(&print_static_field);
2922   st->print_cr(BULLET"---- non-static fields (%d words):", nonstatic_field_size());
2923   FieldPrinter print_nonstatic_field(st);
2924   InstanceKlass* ik = const_cast<InstanceKlass*>(this);
2925   ik->do_nonstatic_fields(&print_nonstatic_field);
2926 
2927   st->print(BULLET"non-static oop maps: ");
2928   OopMapBlock* map     = start_of_nonstatic_oop_maps();
2929   OopMapBlock* end_map = map + nonstatic_oop_map_count();
2930   while (map < end_map) {
2931     st->print("%d-%d ", map->offset(), map->offset() + heapOopSize*(map->count() - 1));
2932     map++;
2933   }
2934   st->cr();
2935 }
2936 
2937 #endif //PRODUCT
2938 
2939 void InstanceKlass::print_value_on(outputStream* st) const {
2940   assert(is_klass(), "must be klass");
2941   if (Verbose || WizardMode)  access_flags().print_on(st);
2942   name()->print_value_on(st);
2943 }
2944 
2945 #ifndef PRODUCT
2946 
2947 void FieldPrinter::do_field(fieldDescriptor* fd) {
2948   _st->print(BULLET);
2949    if (_obj == NULL) {
2950      fd->print_on(_st);
2951      _st->cr();
2952    } else {
2953      fd->print_on_for(_st, _obj);
2954      _st->cr();
2955    }
2956 }
2957 
2958 
2959 void InstanceKlass::oop_print_on(oop obj, outputStream* st) {
2960   Klass::oop_print_on(obj, st);
2961 
2962   if (this == SystemDictionary::String_klass()) {
2963     typeArrayOop value  = java_lang_String::value(obj);
2964     juint        length = java_lang_String::length(obj);
2965     if (value != NULL &&
2966         value->is_typeArray() &&
2967         length <= (juint) value->length()) {
2968       st->print(BULLET"string: ");
2969       java_lang_String::print(obj, st);
2970       st->cr();
2971       if (!WizardMode)  return;  // that is enough
2972     }
2973   }
2974 
2975   st->print_cr(BULLET"---- fields (total size %d words):", oop_size(obj));
2976   FieldPrinter print_field(st, obj);
2977   do_nonstatic_fields(&print_field);
2978 
2979   if (this == SystemDictionary::Class_klass()) {
2980     st->print(BULLET"signature: ");
2981     java_lang_Class::print_signature(obj, st);
2982     st->cr();
2983     Klass* mirrored_klass = java_lang_Class::as_Klass(obj);
2984     st->print(BULLET"fake entry for mirror: ");
2985     mirrored_klass->print_value_on_maybe_null(st);
2986     st->cr();
2987     Klass* array_klass = java_lang_Class::array_klass(obj);
2988     st->print(BULLET"fake entry for array: ");
2989     array_klass->print_value_on_maybe_null(st);
2990     st->cr();
2991     st->print_cr(BULLET"fake entry for oop_size: %d", java_lang_Class::oop_size(obj));
2992     st->print_cr(BULLET"fake entry for static_oop_field_count: %d", java_lang_Class::static_oop_field_count(obj));
2993     Klass* real_klass = java_lang_Class::as_Klass(obj);
2994     if (real_klass != NULL && real_klass->is_instance_klass()) {
2995       InstanceKlass::cast(real_klass)->do_local_static_fields(&print_field);
2996     }
2997   } else if (this == SystemDictionary::MethodType_klass()) {
2998     st->print(BULLET"signature: ");
2999     java_lang_invoke_MethodType::print_signature(obj, st);
3000     st->cr();
3001   }
3002 }
3003 
3004 #endif //PRODUCT
3005 
3006 void InstanceKlass::oop_print_value_on(oop obj, outputStream* st) {
3007   st->print("a ");
3008   name()->print_value_on(st);
3009   obj->print_address_on(st);
3010   if (this == SystemDictionary::String_klass()
3011       && java_lang_String::value(obj) != NULL) {
3012     ResourceMark rm;
3013     int len = java_lang_String::length(obj);
3014     int plen = (len < 24 ? len : 12);
3015     char* str = java_lang_String::as_utf8_string(obj, 0, plen);
3016     st->print(" = \"%s\"", str);
3017     if (len > plen)
3018       st->print("...[%d]", len);
3019   } else if (this == SystemDictionary::Class_klass()) {
3020     Klass* k = java_lang_Class::as_Klass(obj);
3021     st->print(" = ");
3022     if (k != NULL) {
3023       k->print_value_on(st);
3024     } else {
3025       const char* tname = type2name(java_lang_Class::primitive_type(obj));
3026       st->print("%s", tname ? tname : "type?");
3027     }
3028   } else if (this == SystemDictionary::MethodType_klass()) {
3029     st->print(" = ");
3030     java_lang_invoke_MethodType::print_signature(obj, st);
3031   } else if (java_lang_boxing_object::is_instance(obj)) {
3032     st->print(" = ");
3033     java_lang_boxing_object::print(obj, st);
3034   } else if (this == SystemDictionary::LambdaForm_klass()) {
3035     oop vmentry = java_lang_invoke_LambdaForm::vmentry(obj);
3036     if (vmentry != NULL) {
3037       st->print(" => ");
3038       vmentry->print_value_on(st);
3039     }
3040   } else if (this == SystemDictionary::MemberName_klass()) {
3041     Metadata* vmtarget = java_lang_invoke_MemberName::vmtarget(obj);
3042     if (vmtarget != NULL) {
3043       st->print(" = ");
3044       vmtarget->print_value_on(st);
3045     } else {
3046       java_lang_invoke_MemberName::clazz(obj)->print_value_on(st);
3047       st->print(".");
3048       java_lang_invoke_MemberName::name(obj)->print_value_on(st);
3049     }
3050   }
3051 }
3052 
3053 const char* InstanceKlass::internal_name() const {
3054   return external_name();
3055 }
3056 
3057 void InstanceKlass::print_loading_log(LogLevel::type type,
3058                                       ClassLoaderData* loader_data,
3059                                       const char* module_name,
3060                                       const ClassFileStream* cfs) const {
3061   ResourceMark rm;
3062   outputStream* log;
3063 
3064   assert(type == LogLevel::Info || type == LogLevel::Debug, "sanity");
3065 
3066   if (type == LogLevel::Info) {
3067     log = Log(class, load)::info_stream();
3068   } else {
3069     assert(type == LogLevel::Debug,
3070            "print_loading_log supports only Debug and Info levels");
3071     log = Log(class, load)::debug_stream();
3072   }
3073 
3074   // Name and class hierarchy info
3075   log->print("%s", external_name());
3076 
3077   // Source
3078   if (cfs != NULL) {
3079     if (cfs->source() != NULL) {
3080       if (module_name != NULL) {
3081         if (ClassLoader::is_jrt(cfs->source())) {
3082           log->print(" source: jrt:/%s", module_name);
3083         } else {
3084           log->print(" source: %s", cfs->source());
3085         }
3086       } else {
3087         log->print(" source: %s", cfs->source());
3088       }
3089     } else if (loader_data == ClassLoaderData::the_null_class_loader_data()) {
3090       Thread* THREAD = Thread::current();
3091       Klass* caller =
3092             THREAD->is_Java_thread()
3093                 ? ((JavaThread*)THREAD)->security_get_caller_class(1)
3094                 : NULL;
3095       // caller can be NULL, for example, during a JVMTI VM_Init hook
3096       if (caller != NULL) {
3097         log->print(" source: instance of %s", caller->external_name());
3098       } else {
3099         // source is unknown
3100       }
3101     } else {
3102       oop class_loader = loader_data->class_loader();
3103       log->print(" source: %s", class_loader->klass()->external_name());
3104     }
3105   } else {
3106     log->print(" source: shared objects file");
3107   }
3108 
3109   if (type == LogLevel::Debug) {
3110     // Class hierarchy info
3111     log->print(" klass: " INTPTR_FORMAT " super: " INTPTR_FORMAT,
3112                p2i(this),  p2i(superklass()));
3113 
3114     if (local_interfaces() != NULL && local_interfaces()->length() > 0) {
3115       log->print(" interfaces:");
3116       int length = local_interfaces()->length();
3117       for (int i = 0; i < length; i++) {
3118         log->print(" " INTPTR_FORMAT,
3119                    p2i(InstanceKlass::cast(local_interfaces()->at(i))));
3120       }
3121     }
3122 
3123     // Class loader
3124     log->print(" loader: [");
3125     loader_data->print_value_on(log);
3126     log->print("]");
3127 
3128     // Classfile checksum
3129     if (cfs) {
3130       log->print(" bytes: %d checksum: %08x",
3131                  cfs->length(),
3132                  ClassLoader::crc32(0, (const char*)cfs->buffer(),
3133                  cfs->length()));
3134     }
3135   }
3136   log->cr();
3137 }
3138 
3139 #if INCLUDE_SERVICES
3140 // Size Statistics
3141 void InstanceKlass::collect_statistics(KlassSizeStats *sz) const {
3142   Klass::collect_statistics(sz);
3143 
3144   sz->_inst_size  = wordSize * size_helper();
3145   sz->_vtab_bytes = wordSize * vtable_length();
3146   sz->_itab_bytes = wordSize * itable_length();
3147   sz->_nonstatic_oopmap_bytes = wordSize * nonstatic_oop_map_size();
3148 
3149   int n = 0;
3150   n += (sz->_methods_array_bytes         = sz->count_array(methods()));
3151   n += (sz->_method_ordering_bytes       = sz->count_array(method_ordering()));
3152   n += (sz->_local_interfaces_bytes      = sz->count_array(local_interfaces()));
3153   n += (sz->_transitive_interfaces_bytes = sz->count_array(transitive_interfaces()));
3154   n += (sz->_fields_bytes                = sz->count_array(fields()));
3155   n += (sz->_inner_classes_bytes         = sz->count_array(inner_classes()));
3156   sz->_ro_bytes += n;
3157 
3158   const ConstantPool* cp = constants();
3159   if (cp) {
3160     cp->collect_statistics(sz);
3161   }
3162 
3163   const Annotations* anno = annotations();
3164   if (anno) {
3165     anno->collect_statistics(sz);
3166   }
3167 
3168   const Array<Method*>* methods_array = methods();
3169   if (methods()) {
3170     for (int i = 0; i < methods_array->length(); i++) {
3171       Method* method = methods_array->at(i);
3172       if (method) {
3173         sz->_method_count ++;
3174         method->collect_statistics(sz);
3175       }
3176     }
3177   }
3178 }
3179 #endif // INCLUDE_SERVICES
3180 
3181 // Verification
3182 
3183 class VerifyFieldClosure: public OopClosure {
3184  protected:
3185   template <class T> void do_oop_work(T* p) {
3186     oop obj = oopDesc::load_decode_heap_oop(p);
3187     if (!obj->is_oop_or_null()) {
3188       tty->print_cr("Failed: " PTR_FORMAT " -> " PTR_FORMAT, p2i(p), p2i(obj));
3189       Universe::print_on(tty);
3190       guarantee(false, "boom");
3191     }
3192   }
3193  public:
3194   virtual void do_oop(oop* p)       { VerifyFieldClosure::do_oop_work(p); }
3195   virtual void do_oop(narrowOop* p) { VerifyFieldClosure::do_oop_work(p); }
3196 };
3197 
3198 void InstanceKlass::verify_on(outputStream* st) {
3199 #ifndef PRODUCT
3200   // Avoid redundant verifies, this really should be in product.
3201   if (_verify_count == Universe::verify_count()) return;
3202   _verify_count = Universe::verify_count();
3203 #endif
3204 
3205   // Verify Klass
3206   Klass::verify_on(st);
3207 
3208   // Verify that klass is present in ClassLoaderData
3209   guarantee(class_loader_data()->contains_klass(this),
3210             "this class isn't found in class loader data");
3211 
3212   // Verify vtables
3213   if (is_linked()) {
3214     // $$$ This used to be done only for m/s collections.  Doing it
3215     // always seemed a valid generalization.  (DLD -- 6/00)
3216     vtable().verify(st);
3217   }
3218 
3219   // Verify first subklass
3220   if (subklass() != NULL) {
3221     guarantee(subklass()->is_klass(), "should be klass");
3222   }
3223 
3224   // Verify siblings
3225   Klass* super = this->super();
3226   Klass* sib = next_sibling();
3227   if (sib != NULL) {
3228     if (sib == this) {
3229       fatal("subclass points to itself " PTR_FORMAT, p2i(sib));
3230     }
3231 
3232     guarantee(sib->is_klass(), "should be klass");
3233     guarantee(sib->super() == super, "siblings should have same superklass");
3234   }
3235 
3236   // Verify implementor fields
3237   Klass* im = implementor();
3238   if (im != NULL) {
3239     guarantee(is_interface(), "only interfaces should have implementor set");
3240     guarantee(im->is_klass(), "should be klass");
3241     guarantee(!im->is_interface() || im == this,
3242       "implementors cannot be interfaces");
3243   }
3244 
3245   // Verify local interfaces
3246   if (local_interfaces()) {
3247     Array<Klass*>* local_interfaces = this->local_interfaces();
3248     for (int j = 0; j < local_interfaces->length(); j++) {
3249       Klass* e = local_interfaces->at(j);
3250       guarantee(e->is_klass() && e->is_interface(), "invalid local interface");
3251     }
3252   }
3253 
3254   // Verify transitive interfaces
3255   if (transitive_interfaces() != NULL) {
3256     Array<Klass*>* transitive_interfaces = this->transitive_interfaces();
3257     for (int j = 0; j < transitive_interfaces->length(); j++) {
3258       Klass* e = transitive_interfaces->at(j);
3259       guarantee(e->is_klass() && e->is_interface(), "invalid transitive interface");
3260     }
3261   }
3262 
3263   // Verify methods
3264   if (methods() != NULL) {
3265     Array<Method*>* methods = this->methods();
3266     for (int j = 0; j < methods->length(); j++) {
3267       guarantee(methods->at(j)->is_method(), "non-method in methods array");
3268     }
3269     for (int j = 0; j < methods->length() - 1; j++) {
3270       Method* m1 = methods->at(j);
3271       Method* m2 = methods->at(j + 1);
3272       guarantee(m1->name()->fast_compare(m2->name()) <= 0, "methods not sorted correctly");
3273     }
3274   }
3275 
3276   // Verify method ordering
3277   if (method_ordering() != NULL) {
3278     Array<int>* method_ordering = this->method_ordering();
3279     int length = method_ordering->length();
3280     if (JvmtiExport::can_maintain_original_method_order() ||
3281         ((UseSharedSpaces || DumpSharedSpaces) && length != 0)) {
3282       guarantee(length == methods()->length(), "invalid method ordering length");
3283       jlong sum = 0;
3284       for (int j = 0; j < length; j++) {
3285         int original_index = method_ordering->at(j);
3286         guarantee(original_index >= 0, "invalid method ordering index");
3287         guarantee(original_index < length, "invalid method ordering index");
3288         sum += original_index;
3289       }
3290       // Verify sum of indices 0,1,...,length-1
3291       guarantee(sum == ((jlong)length*(length-1))/2, "invalid method ordering sum");
3292     } else {
3293       guarantee(length == 0, "invalid method ordering length");
3294     }
3295   }
3296 
3297   // Verify default methods
3298   if (default_methods() != NULL) {
3299     Array<Method*>* methods = this->default_methods();
3300     for (int j = 0; j < methods->length(); j++) {
3301       guarantee(methods->at(j)->is_method(), "non-method in methods array");
3302     }
3303     for (int j = 0; j < methods->length() - 1; j++) {
3304       Method* m1 = methods->at(j);
3305       Method* m2 = methods->at(j + 1);
3306       guarantee(m1->name()->fast_compare(m2->name()) <= 0, "methods not sorted correctly");
3307     }
3308   }
3309 
3310   // Verify JNI static field identifiers
3311   if (jni_ids() != NULL) {
3312     jni_ids()->verify(this);
3313   }
3314 
3315   // Verify other fields
3316   if (array_klasses() != NULL) {
3317     guarantee(array_klasses()->is_klass(), "should be klass");
3318   }
3319   if (constants() != NULL) {
3320     guarantee(constants()->is_constantPool(), "should be constant pool");
3321   }
3322   const Klass* host = host_klass();
3323   if (host != NULL) {
3324     guarantee(host->is_klass(), "should be klass");
3325   }
3326 }
3327 
3328 void InstanceKlass::oop_verify_on(oop obj, outputStream* st) {
3329   Klass::oop_verify_on(obj, st);
3330   VerifyFieldClosure blk;
3331   obj->oop_iterate_no_header(&blk);
3332 }
3333 
3334 
3335 // JNIid class for jfieldIDs only
3336 // Note to reviewers:
3337 // These JNI functions are just moved over to column 1 and not changed
3338 // in the compressed oops workspace.
3339 JNIid::JNIid(Klass* holder, int offset, JNIid* next) {
3340   _holder = holder;
3341   _offset = offset;
3342   _next = next;
3343   debug_only(_is_static_field_id = false;)
3344 }
3345 
3346 
3347 JNIid* JNIid::find(int offset) {
3348   JNIid* current = this;
3349   while (current != NULL) {
3350     if (current->offset() == offset) return current;
3351     current = current->next();
3352   }
3353   return NULL;
3354 }
3355 
3356 void JNIid::deallocate(JNIid* current) {
3357   while (current != NULL) {
3358     JNIid* next = current->next();
3359     delete current;
3360     current = next;
3361   }
3362 }
3363 
3364 
3365 void JNIid::verify(Klass* holder) {
3366   int first_field_offset  = InstanceMirrorKlass::offset_of_static_fields();
3367   int end_field_offset;
3368   end_field_offset = first_field_offset + (InstanceKlass::cast(holder)->static_field_size() * wordSize);
3369 
3370   JNIid* current = this;
3371   while (current != NULL) {
3372     guarantee(current->holder() == holder, "Invalid klass in JNIid");
3373 #ifdef ASSERT
3374     int o = current->offset();
3375     if (current->is_static_field_id()) {
3376       guarantee(o >= first_field_offset  && o < end_field_offset,  "Invalid static field offset in JNIid");
3377     }
3378 #endif
3379     current = current->next();
3380   }
3381 }
3382 
3383 
3384 #ifdef ASSERT
3385 void InstanceKlass::set_init_state(ClassState state) {
3386   bool good_state = is_shared() ? (_init_state <= state)
3387                                                : (_init_state < state);
3388   assert(good_state || state == allocated, "illegal state transition");
3389   _init_state = (u1)state;
3390 }
3391 #endif
3392 
3393 #if INCLUDE_JVMTI
3394 
3395 // RedefineClasses() support for previous versions
3396 
3397 // Globally, there is at least one previous version of a class to walk
3398 // during class unloading, which is saved because old methods in the class
3399 // are still running.   Otherwise the previous version list is cleaned up.
3400 bool InstanceKlass::_has_previous_versions = false;
3401 
3402 // Returns true if there are previous versions of a class for class
3403 // unloading only. Also resets the flag to false. purge_previous_version
3404 // will set the flag to true if there are any left, i.e., if there's any
3405 // work to do for next time. This is to avoid the expensive code cache
3406 // walk in CLDG::do_unloading().
3407 bool InstanceKlass::has_previous_versions_and_reset() {
3408   bool ret = _has_previous_versions;
3409   log_trace(redefine, class, iklass, purge)("Class unloading: has_previous_versions = %s",
3410      ret ? "true" : "false");
3411   _has_previous_versions = false;
3412   return ret;
3413 }
3414 
3415 // Purge previous versions before adding new previous versions of the class and
3416 // during class unloading.
3417 void InstanceKlass::purge_previous_version_list() {
3418   assert(SafepointSynchronize::is_at_safepoint(), "only called at safepoint");
3419   assert(has_been_redefined(), "Should only be called for main class");
3420 
3421   // Quick exit.
3422   if (previous_versions() == NULL) {
3423     return;
3424   }
3425 
3426   // This klass has previous versions so see what we can cleanup
3427   // while it is safe to do so.
3428 
3429   int deleted_count = 0;    // leave debugging breadcrumbs
3430   int live_count = 0;
3431   ClassLoaderData* loader_data = class_loader_data();
3432   assert(loader_data != NULL, "should never be null");
3433 
3434   ResourceMark rm;
3435   log_trace(redefine, class, iklass, purge)("%s: previous versions", external_name());
3436 
3437   // previous versions are linked together through the InstanceKlass
3438   InstanceKlass* pv_node = previous_versions();
3439   InstanceKlass* last = this;
3440   int version = 0;
3441 
3442   // check the previous versions list
3443   for (; pv_node != NULL; ) {
3444 
3445     ConstantPool* pvcp = pv_node->constants();
3446     assert(pvcp != NULL, "cp ref was unexpectedly cleared");
3447 
3448     if (!pvcp->on_stack()) {
3449       // If the constant pool isn't on stack, none of the methods
3450       // are executing.  Unlink this previous_version.
3451       // The previous version InstanceKlass is on the ClassLoaderData deallocate list
3452       // so will be deallocated during the next phase of class unloading.
3453       log_trace(redefine, class, iklass, purge)
3454         ("previous version " INTPTR_FORMAT " is dead.", p2i(pv_node));
3455       // For debugging purposes.
3456       pv_node->set_is_scratch_class();
3457       // Unlink from previous version list.
3458       assert(pv_node->class_loader_data() == loader_data, "wrong loader_data");
3459       InstanceKlass* next = pv_node->previous_versions();
3460       pv_node->link_previous_versions(NULL);   // point next to NULL
3461       last->link_previous_versions(next);
3462       // Add to the deallocate list after unlinking
3463       loader_data->add_to_deallocate_list(pv_node);
3464       pv_node = next;
3465       deleted_count++;
3466       version++;
3467       continue;
3468     } else {
3469       log_trace(redefine, class, iklass, purge)("previous version " INTPTR_FORMAT " is alive", p2i(pv_node));
3470       assert(pvcp->pool_holder() != NULL, "Constant pool with no holder");
3471       guarantee (!loader_data->is_unloading(), "unloaded classes can't be on the stack");
3472       live_count++;
3473       // found a previous version for next time we do class unloading
3474       _has_previous_versions = true;
3475     }
3476 
3477     // At least one method is live in this previous version.
3478     // Reset dead EMCP methods not to get breakpoints.
3479     // All methods are deallocated when all of the methods for this class are no
3480     // longer running.
3481     Array<Method*>* method_refs = pv_node->methods();
3482     if (method_refs != NULL) {
3483       log_trace(redefine, class, iklass, purge)("previous methods length=%d", method_refs->length());
3484       for (int j = 0; j < method_refs->length(); j++) {
3485         Method* method = method_refs->at(j);
3486 
3487         if (!method->on_stack()) {
3488           // no breakpoints for non-running methods
3489           if (method->is_running_emcp()) {
3490             method->set_running_emcp(false);
3491           }
3492         } else {
3493           assert (method->is_obsolete() || method->is_running_emcp(),
3494                   "emcp method cannot run after emcp bit is cleared");
3495           log_trace(redefine, class, iklass, purge)
3496             ("purge: %s(%s): prev method @%d in version @%d is alive",
3497              method->name()->as_C_string(), method->signature()->as_C_string(), j, version);
3498         }
3499       }
3500     }
3501     // next previous version
3502     last = pv_node;
3503     pv_node = pv_node->previous_versions();
3504     version++;
3505   }
3506   log_trace(redefine, class, iklass, purge)
3507     ("previous version stats: live=%d, deleted=%d", live_count, deleted_count);
3508 }
3509 
3510 void InstanceKlass::mark_newly_obsolete_methods(Array<Method*>* old_methods,
3511                                                 int emcp_method_count) {
3512   int obsolete_method_count = old_methods->length() - emcp_method_count;
3513 
3514   if (emcp_method_count != 0 && obsolete_method_count != 0 &&
3515       _previous_versions != NULL) {
3516     // We have a mix of obsolete and EMCP methods so we have to
3517     // clear out any matching EMCP method entries the hard way.
3518     int local_count = 0;
3519     for (int i = 0; i < old_methods->length(); i++) {
3520       Method* old_method = old_methods->at(i);
3521       if (old_method->is_obsolete()) {
3522         // only obsolete methods are interesting
3523         Symbol* m_name = old_method->name();
3524         Symbol* m_signature = old_method->signature();
3525 
3526         // previous versions are linked together through the InstanceKlass
3527         int j = 0;
3528         for (InstanceKlass* prev_version = _previous_versions;
3529              prev_version != NULL;
3530              prev_version = prev_version->previous_versions(), j++) {
3531 
3532           Array<Method*>* method_refs = prev_version->methods();
3533           for (int k = 0; k < method_refs->length(); k++) {
3534             Method* method = method_refs->at(k);
3535 
3536             if (!method->is_obsolete() &&
3537                 method->name() == m_name &&
3538                 method->signature() == m_signature) {
3539               // The current RedefineClasses() call has made all EMCP
3540               // versions of this method obsolete so mark it as obsolete
3541               log_trace(redefine, class, iklass, add)
3542                 ("%s(%s): flush obsolete method @%d in version @%d",
3543                  m_name->as_C_string(), m_signature->as_C_string(), k, j);
3544 
3545               method->set_is_obsolete();
3546               break;
3547             }
3548           }
3549 
3550           // The previous loop may not find a matching EMCP method, but
3551           // that doesn't mean that we can optimize and not go any
3552           // further back in the PreviousVersion generations. The EMCP
3553           // method for this generation could have already been made obsolete,
3554           // but there still may be an older EMCP method that has not
3555           // been made obsolete.
3556         }
3557 
3558         if (++local_count >= obsolete_method_count) {
3559           // no more obsolete methods so bail out now
3560           break;
3561         }
3562       }
3563     }
3564   }
3565 }
3566 
3567 // Save the scratch_class as the previous version if any of the methods are running.
3568 // The previous_versions are used to set breakpoints in EMCP methods and they are
3569 // also used to clean MethodData links to redefined methods that are no longer running.
3570 void InstanceKlass::add_previous_version(InstanceKlass* scratch_class,
3571                                          int emcp_method_count) {
3572   assert(Thread::current()->is_VM_thread(),
3573          "only VMThread can add previous versions");
3574 
3575   ResourceMark rm;
3576   log_trace(redefine, class, iklass, add)
3577     ("adding previous version ref for %s, EMCP_cnt=%d", scratch_class->external_name(), emcp_method_count);
3578 
3579   // Clean out old previous versions for this class
3580   purge_previous_version_list();
3581 
3582   // Mark newly obsolete methods in remaining previous versions.  An EMCP method from
3583   // a previous redefinition may be made obsolete by this redefinition.
3584   Array<Method*>* old_methods = scratch_class->methods();
3585   mark_newly_obsolete_methods(old_methods, emcp_method_count);
3586 
3587   // If the constant pool for this previous version of the class
3588   // is not marked as being on the stack, then none of the methods
3589   // in this previous version of the class are on the stack so
3590   // we don't need to add this as a previous version.
3591   ConstantPool* cp_ref = scratch_class->constants();
3592   if (!cp_ref->on_stack()) {
3593     log_trace(redefine, class, iklass, add)("scratch class not added; no methods are running");
3594     // For debugging purposes.
3595     scratch_class->set_is_scratch_class();
3596     scratch_class->class_loader_data()->add_to_deallocate_list(scratch_class);
3597     return;
3598   }
3599 
3600   if (emcp_method_count != 0) {
3601     // At least one method is still running, check for EMCP methods
3602     for (int i = 0; i < old_methods->length(); i++) {
3603       Method* old_method = old_methods->at(i);
3604       if (!old_method->is_obsolete() && old_method->on_stack()) {
3605         // if EMCP method (not obsolete) is on the stack, mark as EMCP so that
3606         // we can add breakpoints for it.
3607 
3608         // We set the method->on_stack bit during safepoints for class redefinition
3609         // and use this bit to set the is_running_emcp bit.
3610         // After the safepoint, the on_stack bit is cleared and the running emcp
3611         // method may exit.   If so, we would set a breakpoint in a method that
3612         // is never reached, but this won't be noticeable to the programmer.
3613         old_method->set_running_emcp(true);
3614         log_trace(redefine, class, iklass, add)
3615           ("EMCP method %s is on_stack " INTPTR_FORMAT, old_method->name_and_sig_as_C_string(), p2i(old_method));
3616       } else if (!old_method->is_obsolete()) {
3617         log_trace(redefine, class, iklass, add)
3618           ("EMCP method %s is NOT on_stack " INTPTR_FORMAT, old_method->name_and_sig_as_C_string(), p2i(old_method));
3619       }
3620     }
3621   }
3622 
3623   // Add previous version if any methods are still running.
3624   // Set has_previous_version flag for processing during class unloading.
3625   _has_previous_versions = true;
3626   log_trace(redefine, class, iklass, add) ("scratch class added; one of its methods is on_stack.");
3627   assert(scratch_class->previous_versions() == NULL, "shouldn't have a previous version");
3628   scratch_class->link_previous_versions(previous_versions());
3629   link_previous_versions(scratch_class);
3630 } // end add_previous_version()
3631 
3632 #endif // INCLUDE_JVMTI
3633 
3634 Method* InstanceKlass::method_with_idnum(int idnum) {
3635   Method* m = NULL;
3636   if (idnum < methods()->length()) {
3637     m = methods()->at(idnum);
3638   }
3639   if (m == NULL || m->method_idnum() != idnum) {
3640     for (int index = 0; index < methods()->length(); ++index) {
3641       m = methods()->at(index);
3642       if (m->method_idnum() == idnum) {
3643         return m;
3644       }
3645     }
3646     // None found, return null for the caller to handle.
3647     return NULL;
3648   }
3649   return m;
3650 }
3651 
3652 
3653 Method* InstanceKlass::method_with_orig_idnum(int idnum) {
3654   if (idnum >= methods()->length()) {
3655     return NULL;
3656   }
3657   Method* m = methods()->at(idnum);
3658   if (m != NULL && m->orig_method_idnum() == idnum) {
3659     return m;
3660   }
3661   // Obsolete method idnum does not match the original idnum
3662   for (int index = 0; index < methods()->length(); ++index) {
3663     m = methods()->at(index);
3664     if (m->orig_method_idnum() == idnum) {
3665       return m;
3666     }
3667   }
3668   // None found, return null for the caller to handle.
3669   return NULL;
3670 }
3671 
3672 
3673 Method* InstanceKlass::method_with_orig_idnum(int idnum, int version) {
3674   InstanceKlass* holder = get_klass_version(version);
3675   if (holder == NULL) {
3676     return NULL; // The version of klass is gone, no method is found
3677   }
3678   Method* method = holder->method_with_orig_idnum(idnum);
3679   return method;
3680 }
3681 
3682 #if INCLUDE_JVMTI
3683 JvmtiCachedClassFileData* InstanceKlass::get_cached_class_file() {
3684   if (MetaspaceShared::is_in_shared_space(_cached_class_file)) {
3685     // Ignore the archived class stream data
3686     return NULL;
3687   } else {
3688     return _cached_class_file;
3689   }
3690 }
3691 
3692 jint InstanceKlass::get_cached_class_file_len() {
3693   return VM_RedefineClasses::get_cached_class_file_len(_cached_class_file);
3694 }
3695 
3696 unsigned char * InstanceKlass::get_cached_class_file_bytes() {
3697   return VM_RedefineClasses::get_cached_class_file_bytes(_cached_class_file);
3698 }
3699 
3700 #if INCLUDE_CDS
3701 JvmtiCachedClassFileData* InstanceKlass::get_archived_class_data() {
3702   assert(this->is_shared(), "class should be shared");
3703   if (MetaspaceShared::is_in_shared_space(_cached_class_file)) {
3704     return _cached_class_file;
3705   } else {
3706     return NULL;
3707   }
3708 }
3709 #endif
3710 #endif