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 "logging/logMessage.hpp"
  45 #include "logging/logStream.hpp"
  46 #include "memory/heapInspection.hpp"
  47 #include "memory/iterator.inline.hpp"
  48 #include "memory/metadataFactory.hpp"
  49 #include "memory/metaspaceClosure.hpp"
  50 #include "memory/metaspaceShared.hpp"
  51 #include "memory/oopFactory.hpp"
  52 #include "memory/resourceArea.hpp"
  53 #include "oops/fieldStreams.hpp"
  54 #include "oops/instanceClassLoaderKlass.hpp"
  55 #include "oops/instanceKlass.inline.hpp"
  56 #include "oops/instanceMirrorKlass.hpp"
  57 #include "oops/instanceOop.hpp"
  58 #include "oops/klass.inline.hpp"
  59 #include "oops/method.hpp"
  60 #include "oops/oop.inline.hpp"
  61 #include "oops/symbol.hpp"
  62 #include "prims/jvm.h"
  63 #include "prims/jvmtiExport.hpp"
  64 #include "prims/jvmtiRedefineClasses.hpp"
  65 #include "prims/jvmtiThreadState.hpp"
  66 #include "prims/methodComparator.hpp"
  67 #include "runtime/atomic.hpp"
  68 #include "runtime/fieldDescriptor.hpp"
  69 #include "runtime/handles.inline.hpp"
  70 #include "runtime/javaCalls.hpp"
  71 #include "runtime/mutexLocker.hpp"
  72 #include "runtime/orderAccess.inline.hpp"
  73 #include "runtime/thread.inline.hpp"
  74 #include "services/classLoadingService.hpp"
  75 #include "services/threadService.hpp"
  76 #include "utilities/dtrace.hpp"
  77 #include "utilities/macros.hpp"
  78 #include "utilities/stringUtils.hpp"
  79 #ifdef COMPILER1
  80 #include "c1/c1_Compiler.hpp"
  81 #endif
  82 
  83 #ifdef DTRACE_ENABLED
  84 
  85 
  86 #define HOTSPOT_CLASS_INITIALIZATION_required HOTSPOT_CLASS_INITIALIZATION_REQUIRED
  87 #define HOTSPOT_CLASS_INITIALIZATION_recursive HOTSPOT_CLASS_INITIALIZATION_RECURSIVE
  88 #define HOTSPOT_CLASS_INITIALIZATION_concurrent HOTSPOT_CLASS_INITIALIZATION_CONCURRENT
  89 #define HOTSPOT_CLASS_INITIALIZATION_erroneous HOTSPOT_CLASS_INITIALIZATION_ERRONEOUS
  90 #define HOTSPOT_CLASS_INITIALIZATION_super__failed HOTSPOT_CLASS_INITIALIZATION_SUPER_FAILED
  91 #define HOTSPOT_CLASS_INITIALIZATION_clinit HOTSPOT_CLASS_INITIALIZATION_CLINIT
  92 #define HOTSPOT_CLASS_INITIALIZATION_error HOTSPOT_CLASS_INITIALIZATION_ERROR
  93 #define HOTSPOT_CLASS_INITIALIZATION_end HOTSPOT_CLASS_INITIALIZATION_END
  94 #define DTRACE_CLASSINIT_PROBE(type, thread_type)                \
  95   {                                                              \
  96     char* data = NULL;                                           \
  97     int len = 0;                                                 \
  98     Symbol* clss_name = name();                                  \
  99     if (clss_name != NULL) {                                     \
 100       data = (char*)clss_name->bytes();                          \
 101       len = clss_name->utf8_length();                            \
 102     }                                                            \
 103     HOTSPOT_CLASS_INITIALIZATION_##type(                         \
 104       data, len, (void*)class_loader(), thread_type);            \
 105   }
 106 
 107 #define DTRACE_CLASSINIT_PROBE_WAIT(type, thread_type, wait)     \
 108   {                                                              \
 109     char* data = NULL;                                           \
 110     int len = 0;                                                 \
 111     Symbol* clss_name = name();                                  \
 112     if (clss_name != NULL) {                                     \
 113       data = (char*)clss_name->bytes();                          \
 114       len = clss_name->utf8_length();                            \
 115     }                                                            \
 116     HOTSPOT_CLASS_INITIALIZATION_##type(                         \
 117       data, len, (void*)class_loader(), thread_type, wait);      \
 118   }
 119 
 120 #else //  ndef DTRACE_ENABLED
 121 
 122 #define DTRACE_CLASSINIT_PROBE(type, thread_type)
 123 #define DTRACE_CLASSINIT_PROBE_WAIT(type, thread_type, wait)
 124 
 125 #endif //  ndef DTRACE_ENABLED
 126 
 127 volatile int InstanceKlass::_total_instanceKlass_count = 0;
 128 
 129 static inline bool is_class_loader(const Symbol* class_name,
 130                                    const ClassFileParser& parser) {
 131   assert(class_name != NULL, "invariant");
 132 
 133   if (class_name == vmSymbols::java_lang_ClassLoader()) {
 134     return true;
 135   }
 136 
 137   if (SystemDictionary::ClassLoader_klass_loaded()) {
 138     const Klass* const super_klass = parser.super_klass();
 139     if (super_klass != NULL) {
 140       if (super_klass->is_subtype_of(SystemDictionary::ClassLoader_klass())) {
 141         return true;
 142       }
 143     }
 144   }
 145   return false;
 146 }
 147 
 148 InstanceKlass* InstanceKlass::allocate_instance_klass(const ClassFileParser& parser, TRAPS) {
 149   const int size = InstanceKlass::size(parser.vtable_size(),
 150                                        parser.itable_size(),
 151                                        nonstatic_oop_map_size(parser.total_oop_map_count()),
 152                                        parser.is_interface(),
 153                                        parser.is_anonymous(),
 154                                        should_store_fingerprint());
 155 
 156   const Symbol* const class_name = parser.class_name();
 157   assert(class_name != NULL, "invariant");
 158   ClassLoaderData* loader_data = parser.loader_data();
 159   assert(loader_data != NULL, "invariant");
 160 
 161   InstanceKlass* ik;
 162 
 163   // Allocation
 164   if (REF_NONE == parser.reference_type()) {
 165     if (class_name == vmSymbols::java_lang_Class()) {
 166       // mirror
 167       ik = new (loader_data, size, THREAD) InstanceMirrorKlass(parser);
 168     }
 169     else if (is_class_loader(class_name, parser)) {
 170       // class loader
 171       ik = new (loader_data, size, THREAD) InstanceClassLoaderKlass(parser);
 172     }
 173     else {
 174       // normal
 175       ik = new (loader_data, size, THREAD) InstanceKlass(parser, InstanceKlass::_misc_kind_other);
 176     }
 177   }
 178   else {
 179     // reference
 180     ik = new (loader_data, size, THREAD) InstanceRefKlass(parser);
 181   }
 182 
 183   // Check for pending exception before adding to the loader data and incrementing
 184   // class count.  Can get OOM here.
 185   if (HAS_PENDING_EXCEPTION) {
 186     return NULL;
 187   }
 188 
 189   assert(ik != NULL, "invariant");
 190 
 191   const bool publicize = !parser.is_internal();
 192 
 193   // Add all classes to our internal class loader list here,
 194   // including classes in the bootstrap (NULL) class loader.
 195   loader_data->add_class(ik, publicize);
 196   Atomic::inc(&_total_instanceKlass_count);
 197 
 198   return ik;
 199 }
 200 
 201 
 202 // copy method ordering from resource area to Metaspace
 203 void InstanceKlass::copy_method_ordering(const intArray* m, TRAPS) {
 204   if (m != NULL) {
 205     // allocate a new array and copy contents (memcpy?)
 206     _method_ordering = MetadataFactory::new_array<int>(class_loader_data(), m->length(), CHECK);
 207     for (int i = 0; i < m->length(); i++) {
 208       _method_ordering->at_put(i, m->at(i));
 209     }
 210   } else {
 211     _method_ordering = Universe::the_empty_int_array();
 212   }
 213 }
 214 
 215 // create a new array of vtable_indices for default methods
 216 Array<int>* InstanceKlass::create_new_default_vtable_indices(int len, TRAPS) {
 217   Array<int>* vtable_indices = MetadataFactory::new_array<int>(class_loader_data(), len, CHECK_NULL);
 218   assert(default_vtable_indices() == NULL, "only create once");
 219   set_default_vtable_indices(vtable_indices);
 220   return vtable_indices;
 221 }
 222 
 223 InstanceKlass::InstanceKlass(const ClassFileParser& parser, unsigned kind) :
 224   _static_field_size(parser.static_field_size()),
 225   _nonstatic_oop_map_size(nonstatic_oop_map_size(parser.total_oop_map_count())),
 226   _itable_len(parser.itable_size()),
 227   _reference_type(parser.reference_type()) {
 228     set_vtable_length(parser.vtable_size());
 229     set_kind(kind);
 230     set_access_flags(parser.access_flags());
 231     set_is_anonymous(parser.is_anonymous());
 232     set_layout_helper(Klass::instance_layout_helper(parser.layout_size(),
 233                                                     false));
 234 
 235     assert(NULL == _methods, "underlying memory not zeroed?");
 236     assert(is_instance_klass(), "is layout incorrect?");
 237     assert(size_helper() == parser.layout_size(), "incorrect size_helper?");
 238 }
 239 
 240 void InstanceKlass::deallocate_methods(ClassLoaderData* loader_data,
 241                                        Array<Method*>* methods) {
 242   if (methods != NULL && methods != Universe::the_empty_method_array() &&
 243       !methods->is_shared()) {
 244     for (int i = 0; i < methods->length(); i++) {
 245       Method* method = methods->at(i);
 246       if (method == NULL) continue;  // maybe null if error processing
 247       // Only want to delete methods that are not executing for RedefineClasses.
 248       // The previous version will point to them so they're not totally dangling
 249       assert (!method->on_stack(), "shouldn't be called with methods on stack");
 250       MetadataFactory::free_metadata(loader_data, method);
 251     }
 252     MetadataFactory::free_array<Method*>(loader_data, methods);
 253   }
 254 }
 255 
 256 void InstanceKlass::deallocate_interfaces(ClassLoaderData* loader_data,
 257                                           const Klass* super_klass,
 258                                           Array<Klass*>* local_interfaces,
 259                                           Array<Klass*>* transitive_interfaces) {
 260   // Only deallocate transitive interfaces if not empty, same as super class
 261   // or same as local interfaces.  See code in parseClassFile.
 262   Array<Klass*>* ti = transitive_interfaces;
 263   if (ti != Universe::the_empty_klass_array() && ti != local_interfaces) {
 264     // check that the interfaces don't come from super class
 265     Array<Klass*>* sti = (super_klass == NULL) ? NULL :
 266                     InstanceKlass::cast(super_klass)->transitive_interfaces();
 267     if (ti != sti && ti != NULL && !ti->is_shared()) {
 268       MetadataFactory::free_array<Klass*>(loader_data, ti);
 269     }
 270   }
 271 
 272   // local interfaces can be empty
 273   if (local_interfaces != Universe::the_empty_klass_array() &&
 274       local_interfaces != NULL && !local_interfaces->is_shared()) {
 275     MetadataFactory::free_array<Klass*>(loader_data, local_interfaces);
 276   }
 277 }
 278 
 279 // This function deallocates the metadata and C heap pointers that the
 280 // InstanceKlass points to.
 281 void InstanceKlass::deallocate_contents(ClassLoaderData* loader_data) {
 282 
 283   // Orphan the mirror first, CMS thinks it's still live.
 284   if (java_mirror() != NULL) {
 285     java_lang_Class::set_klass(java_mirror(), NULL);
 286   }
 287 
 288   // Need to take this class off the class loader data list.
 289   loader_data->remove_class(this);
 290 
 291   // The array_klass for this class is created later, after error handling.
 292   // For class redefinition, we keep the original class so this scratch class
 293   // doesn't have an array class.  Either way, assert that there is nothing
 294   // to deallocate.
 295   assert(array_klasses() == NULL, "array classes shouldn't be created for this class yet");
 296 
 297   // Release C heap allocated data that this might point to, which includes
 298   // reference counting symbol names.
 299   release_C_heap_structures();
 300 
 301   deallocate_methods(loader_data, methods());
 302   set_methods(NULL);
 303 
 304   if (method_ordering() != NULL &&
 305       method_ordering() != Universe::the_empty_int_array() &&
 306       !method_ordering()->is_shared()) {
 307     MetadataFactory::free_array<int>(loader_data, method_ordering());
 308   }
 309   set_method_ordering(NULL);
 310 
 311   // default methods can be empty
 312   if (default_methods() != NULL &&
 313       default_methods() != Universe::the_empty_method_array() &&
 314       !default_methods()->is_shared()) {
 315     MetadataFactory::free_array<Method*>(loader_data, default_methods());
 316   }
 317   // Do NOT deallocate the default methods, they are owned by superinterfaces.
 318   set_default_methods(NULL);
 319 
 320   // default methods vtable indices can be empty
 321   if (default_vtable_indices() != NULL &&
 322       !default_vtable_indices()->is_shared()) {
 323     MetadataFactory::free_array<int>(loader_data, default_vtable_indices());
 324   }
 325   set_default_vtable_indices(NULL);
 326 
 327 
 328   // This array is in Klass, but remove it with the InstanceKlass since
 329   // this place would be the only caller and it can share memory with transitive
 330   // interfaces.
 331   if (secondary_supers() != NULL &&
 332       secondary_supers() != Universe::the_empty_klass_array() &&
 333       secondary_supers() != transitive_interfaces() &&
 334       !secondary_supers()->is_shared()) {
 335     MetadataFactory::free_array<Klass*>(loader_data, secondary_supers());
 336   }
 337   set_secondary_supers(NULL);
 338 
 339   deallocate_interfaces(loader_data, super(), local_interfaces(), transitive_interfaces());
 340   set_transitive_interfaces(NULL);
 341   set_local_interfaces(NULL);
 342 
 343   if (fields() != NULL && !fields()->is_shared()) {
 344     MetadataFactory::free_array<jushort>(loader_data, fields());
 345   }
 346   set_fields(NULL, 0);
 347 
 348   // If a method from a redefined class is using this constant pool, don't
 349   // delete it, yet.  The new class's previous version will point to this.
 350   if (constants() != NULL) {
 351     assert (!constants()->on_stack(), "shouldn't be called if anything is onstack");
 352     if (!constants()->is_shared()) {
 353       MetadataFactory::free_metadata(loader_data, constants());
 354     }
 355     // Delete any cached resolution errors for the constant pool
 356     SystemDictionary::delete_resolution_error(constants());
 357 
 358     set_constants(NULL);
 359   }
 360 
 361   if (inner_classes() != NULL &&
 362       inner_classes() != Universe::the_empty_short_array() &&
 363       !inner_classes()->is_shared()) {
 364     MetadataFactory::free_array<jushort>(loader_data, inner_classes());
 365   }
 366   set_inner_classes(NULL);
 367 
 368   // We should deallocate the Annotations instance if it's not in shared spaces.
 369   if (annotations() != NULL && !annotations()->is_shared()) {
 370     MetadataFactory::free_metadata(loader_data, annotations());
 371   }
 372   set_annotations(NULL);
 373 }
 374 
 375 bool InstanceKlass::should_be_initialized() const {
 376   return !is_initialized();
 377 }
 378 
 379 klassItable InstanceKlass::itable() const {
 380   return klassItable(const_cast<InstanceKlass*>(this));
 381 }
 382 
 383 void InstanceKlass::eager_initialize(Thread *thread) {
 384   if (!EagerInitialization) return;
 385 
 386   if (this->is_not_initialized()) {
 387     // abort if the the class has a class initializer
 388     if (this->class_initializer() != NULL) return;
 389 
 390     // abort if it is java.lang.Object (initialization is handled in genesis)
 391     Klass* super_klass = super();
 392     if (super_klass == NULL) return;
 393 
 394     // abort if the super class should be initialized
 395     if (!InstanceKlass::cast(super_klass)->is_initialized()) return;
 396 
 397     // call body to expose the this pointer
 398     eager_initialize_impl();
 399   }
 400 }
 401 
 402 // JVMTI spec thinks there are signers and protection domain in the
 403 // instanceKlass.  These accessors pretend these fields are there.
 404 // The hprof specification also thinks these fields are in InstanceKlass.
 405 oop InstanceKlass::protection_domain() const {
 406   // return the protection_domain from the mirror
 407   return java_lang_Class::protection_domain(java_mirror());
 408 }
 409 
 410 // To remove these from requires an incompatible change and CCC request.
 411 objArrayOop InstanceKlass::signers() const {
 412   // return the signers from the mirror
 413   return java_lang_Class::signers(java_mirror());
 414 }
 415 
 416 oop InstanceKlass::init_lock() const {
 417   // return the init lock from the mirror
 418   oop lock = java_lang_Class::init_lock(java_mirror());
 419   // Prevent reordering with any access of initialization state
 420   OrderAccess::loadload();
 421   assert((oop)lock != NULL || !is_not_initialized(), // initialized or in_error state
 422          "only fully initialized state can have a null lock");
 423   return lock;
 424 }
 425 
 426 // Set the initialization lock to null so the object can be GC'ed.  Any racing
 427 // threads to get this lock will see a null lock and will not lock.
 428 // That's okay because they all check for initialized state after getting
 429 // the lock and return.
 430 void InstanceKlass::fence_and_clear_init_lock() {
 431   // make sure previous stores are all done, notably the init_state.
 432   OrderAccess::storestore();
 433   java_lang_Class::set_init_lock(java_mirror(), NULL);
 434   assert(!is_not_initialized(), "class must be initialized now");
 435 }
 436 
 437 void InstanceKlass::eager_initialize_impl() {
 438   EXCEPTION_MARK;
 439   HandleMark hm(THREAD);
 440   Handle h_init_lock(THREAD, init_lock());
 441   ObjectLocker ol(h_init_lock, THREAD, h_init_lock() != NULL);
 442 
 443   // abort if someone beat us to the initialization
 444   if (!is_not_initialized()) return;  // note: not equivalent to is_initialized()
 445 
 446   ClassState old_state = init_state();
 447   link_class_impl(true, THREAD);
 448   if (HAS_PENDING_EXCEPTION) {
 449     CLEAR_PENDING_EXCEPTION;
 450     // Abort if linking the class throws an exception.
 451 
 452     // Use a test to avoid redundantly resetting the state if there's
 453     // no change.  Set_init_state() asserts that state changes make
 454     // progress, whereas here we might just be spinning in place.
 455     if (old_state != _init_state)
 456       set_init_state(old_state);
 457   } else {
 458     // linking successfull, mark class as initialized
 459     set_init_state(fully_initialized);
 460     fence_and_clear_init_lock();
 461     // trace
 462     if (log_is_enabled(Info, class, init)) {
 463       ResourceMark rm(THREAD);
 464       log_info(class, init)("[Initialized %s without side effects]", external_name());
 465     }
 466   }
 467 }
 468 
 469 
 470 // See "The Virtual Machine Specification" section 2.16.5 for a detailed explanation of the class initialization
 471 // process. The step comments refers to the procedure described in that section.
 472 // Note: implementation moved to static method to expose the this pointer.
 473 void InstanceKlass::initialize(TRAPS) {
 474   if (this->should_be_initialized()) {
 475     initialize_impl(CHECK);
 476     // Note: at this point the class may be initialized
 477     //       OR it may be in the state of being initialized
 478     //       in case of recursive initialization!
 479   } else {
 480     assert(is_initialized(), "sanity check");
 481   }
 482 }
 483 
 484 
 485 bool InstanceKlass::verify_code(bool throw_verifyerror, TRAPS) {
 486   // 1) Verify the bytecodes
 487   Verifier::Mode mode =
 488     throw_verifyerror ? Verifier::ThrowException : Verifier::NoException;
 489   return Verifier::verify(this, mode, should_verify_class(), THREAD);
 490 }
 491 
 492 
 493 // Used exclusively by the shared spaces dump mechanism to prevent
 494 // classes mapped into the shared regions in new VMs from appearing linked.
 495 
 496 void InstanceKlass::unlink_class() {
 497   assert(is_linked(), "must be linked");
 498   _init_state = loaded;
 499 }
 500 
 501 void InstanceKlass::link_class(TRAPS) {
 502   assert(is_loaded(), "must be loaded");
 503   if (!is_linked()) {
 504     link_class_impl(true, CHECK);
 505   }
 506 }
 507 
 508 // Called to verify that a class can link during initialization, without
 509 // throwing a VerifyError.
 510 bool InstanceKlass::link_class_or_fail(TRAPS) {
 511   assert(is_loaded(), "must be loaded");
 512   if (!is_linked()) {
 513     link_class_impl(false, CHECK_false);
 514   }
 515   return is_linked();
 516 }
 517 
 518 bool InstanceKlass::link_class_impl(bool throw_verifyerror, TRAPS) {
 519   if (DumpSharedSpaces && is_in_error_state()) {
 520     // This is for CDS dumping phase only -- we use the in_error_state to indicate that
 521     // the class has failed verification. Throwing the NoClassDefFoundError here is just
 522     // a convenient way to stop repeat attempts to verify the same (bad) class.
 523     //
 524     // Note that the NoClassDefFoundError is not part of the JLS, and should not be thrown
 525     // if we are executing Java code. This is not a problem for CDS dumping phase since
 526     // it doesn't execute any Java code.
 527     ResourceMark rm(THREAD);
 528     Exceptions::fthrow(THREAD_AND_LOCATION,
 529                        vmSymbols::java_lang_NoClassDefFoundError(),
 530                        "Class %s, or one of its supertypes, failed class initialization",
 531                        external_name());
 532     return false;
 533   }
 534   // return if already verified
 535   if (is_linked()) {
 536     return true;
 537   }
 538 
 539   // Timing
 540   // timer handles recursion
 541   assert(THREAD->is_Java_thread(), "non-JavaThread in link_class_impl");
 542   JavaThread* jt = (JavaThread*)THREAD;
 543 
 544   // link super class before linking this class
 545   Klass* super_klass = super();
 546   if (super_klass != NULL) {
 547     if (super_klass->is_interface()) {  // check if super class is an interface
 548       ResourceMark rm(THREAD);
 549       Exceptions::fthrow(
 550         THREAD_AND_LOCATION,
 551         vmSymbols::java_lang_IncompatibleClassChangeError(),
 552         "class %s has interface %s as super class",
 553         external_name(),
 554         super_klass->external_name()
 555       );
 556       return false;
 557     }
 558 
 559     InstanceKlass* ik_super = InstanceKlass::cast(super_klass);
 560     ik_super->link_class_impl(throw_verifyerror, CHECK_false);
 561   }
 562 
 563   // link all interfaces implemented by this class before linking this class
 564   Array<Klass*>* interfaces = local_interfaces();
 565   int num_interfaces = interfaces->length();
 566   for (int index = 0; index < num_interfaces; index++) {
 567     InstanceKlass* interk = InstanceKlass::cast(interfaces->at(index));
 568     interk->link_class_impl(throw_verifyerror, CHECK_false);
 569   }
 570 
 571   // in case the class is linked in the process of linking its superclasses
 572   if (is_linked()) {
 573     return true;
 574   }
 575 
 576   // trace only the link time for this klass that includes
 577   // the verification time
 578   PerfClassTraceTime vmtimer(ClassLoader::perf_class_link_time(),
 579                              ClassLoader::perf_class_link_selftime(),
 580                              ClassLoader::perf_classes_linked(),
 581                              jt->get_thread_stat()->perf_recursion_counts_addr(),
 582                              jt->get_thread_stat()->perf_timers_addr(),
 583                              PerfClassTraceTime::CLASS_LINK);
 584 
 585   // verification & rewriting
 586   {
 587     HandleMark hm(THREAD);
 588     Handle h_init_lock(THREAD, init_lock());
 589     ObjectLocker ol(h_init_lock, THREAD, h_init_lock() != NULL);
 590     // rewritten will have been set if loader constraint error found
 591     // on an earlier link attempt
 592     // don't verify or rewrite if already rewritten
 593     //
 594 
 595     if (!is_linked()) {
 596       if (!is_rewritten()) {
 597         {
 598           bool verify_ok = verify_code(throw_verifyerror, THREAD);
 599           if (!verify_ok) {
 600             return false;
 601           }
 602         }
 603 
 604         // Just in case a side-effect of verify linked this class already
 605         // (which can sometimes happen since the verifier loads classes
 606         // using custom class loaders, which are free to initialize things)
 607         if (is_linked()) {
 608           return true;
 609         }
 610 
 611         // also sets rewritten
 612         rewrite_class(CHECK_false);
 613       } else if (is_shared()) {
 614         SystemDictionaryShared::check_verification_constraints(this, CHECK_false);
 615       }
 616 
 617       // relocate jsrs and link methods after they are all rewritten
 618       link_methods(CHECK_false);
 619 
 620       // Initialize the vtable and interface table after
 621       // methods have been rewritten since rewrite may
 622       // fabricate new Method*s.
 623       // also does loader constraint checking
 624       //
 625       // initialize_vtable and initialize_itable need to be rerun for
 626       // a shared class if the class is not loaded by the NULL classloader.
 627       ClassLoaderData * loader_data = class_loader_data();
 628       if (!(is_shared() &&
 629             loader_data->is_the_null_class_loader_data())) {
 630         ResourceMark rm(THREAD);
 631         vtable().initialize_vtable(true, CHECK_false);
 632         itable().initialize_itable(true, CHECK_false);
 633       }
 634 #ifdef ASSERT
 635       else {
 636         vtable().verify(tty, true);
 637         // In case itable verification is ever added.
 638         // itable().verify(tty, true);
 639       }
 640 #endif
 641       set_init_state(linked);
 642       if (JvmtiExport::should_post_class_prepare()) {
 643         Thread *thread = THREAD;
 644         assert(thread->is_Java_thread(), "thread->is_Java_thread()");
 645         JvmtiExport::post_class_prepare((JavaThread *) thread, this);
 646       }
 647     }
 648   }
 649   return true;
 650 }
 651 
 652 
 653 // Rewrite the byte codes of all of the methods of a class.
 654 // The rewriter must be called exactly once. Rewriting must happen after
 655 // verification but before the first method of the class is executed.
 656 void InstanceKlass::rewrite_class(TRAPS) {
 657   assert(is_loaded(), "must be loaded");
 658   if (is_rewritten()) {
 659     assert(is_shared(), "rewriting an unshared class?");
 660     return;
 661   }
 662   Rewriter::rewrite(this, CHECK);
 663   set_rewritten();
 664 }
 665 
 666 // Now relocate and link method entry points after class is rewritten.
 667 // This is outside is_rewritten flag. In case of an exception, it can be
 668 // executed more than once.
 669 void InstanceKlass::link_methods(TRAPS) {
 670   int len = methods()->length();
 671   for (int i = len-1; i >= 0; i--) {
 672     methodHandle m(THREAD, methods()->at(i));
 673 
 674     // Set up method entry points for compiler and interpreter    .
 675     m->link_method(m, CHECK);
 676   }
 677 }
 678 
 679 // Eagerly initialize superinterfaces that declare default methods (concrete instance: any access)
 680 void InstanceKlass::initialize_super_interfaces(TRAPS) {
 681   assert (has_nonstatic_concrete_methods(), "caller should have checked this");
 682   for (int i = 0; i < local_interfaces()->length(); ++i) {
 683     Klass* iface = local_interfaces()->at(i);
 684     InstanceKlass* ik = InstanceKlass::cast(iface);
 685 
 686     // Initialization is depth first search ie. we start with top of the inheritance tree
 687     // has_nonstatic_concrete_methods drives searching superinterfaces since it
 688     // means has_nonstatic_concrete_methods in its superinterface hierarchy
 689     if (ik->has_nonstatic_concrete_methods()) {
 690       ik->initialize_super_interfaces(CHECK);
 691     }
 692 
 693     // Only initialize() interfaces that "declare" concrete methods.
 694     if (ik->should_be_initialized() && ik->declares_nonstatic_concrete_methods()) {
 695       ik->initialize(CHECK);
 696     }
 697   }
 698 }
 699 
 700 void InstanceKlass::initialize_impl(TRAPS) {
 701   HandleMark hm(THREAD);
 702 
 703   // Make sure klass is linked (verified) before initialization
 704   // A class could already be verified, since it has been reflected upon.
 705   link_class(CHECK);
 706 
 707   DTRACE_CLASSINIT_PROBE(required, -1);
 708 
 709   bool wait = false;
 710 
 711   // refer to the JVM book page 47 for description of steps
 712   // Step 1
 713   {
 714     Handle h_init_lock(THREAD, init_lock());
 715     ObjectLocker ol(h_init_lock, THREAD, h_init_lock() != NULL);
 716 
 717     Thread *self = THREAD; // it's passed the current thread
 718 
 719     // Step 2
 720     // If we were to use wait() instead of waitInterruptibly() then
 721     // we might end up throwing IE from link/symbol resolution sites
 722     // that aren't expected to throw.  This would wreak havoc.  See 6320309.
 723     while(is_being_initialized() && !is_reentrant_initialization(self)) {
 724         wait = true;
 725       ol.waitUninterruptibly(CHECK);
 726     }
 727 
 728     // Step 3
 729     if (is_being_initialized() && is_reentrant_initialization(self)) {
 730       DTRACE_CLASSINIT_PROBE_WAIT(recursive, -1, wait);
 731       return;
 732     }
 733 
 734     // Step 4
 735     if (is_initialized()) {
 736       DTRACE_CLASSINIT_PROBE_WAIT(concurrent, -1, wait);
 737       return;
 738     }
 739 
 740     // Step 5
 741     if (is_in_error_state()) {
 742       DTRACE_CLASSINIT_PROBE_WAIT(erroneous, -1, wait);
 743       ResourceMark rm(THREAD);
 744       const char* desc = "Could not initialize class ";
 745       const char* className = external_name();
 746       size_t msglen = strlen(desc) + strlen(className) + 1;
 747       char* message = NEW_RESOURCE_ARRAY(char, msglen);
 748       if (NULL == message) {
 749         // Out of memory: can't create detailed error message
 750         THROW_MSG(vmSymbols::java_lang_NoClassDefFoundError(), className);
 751       } else {
 752         jio_snprintf(message, msglen, "%s%s", desc, className);
 753         THROW_MSG(vmSymbols::java_lang_NoClassDefFoundError(), message);
 754       }
 755     }
 756 
 757     // Step 6
 758     set_init_state(being_initialized);
 759     set_init_thread(self);
 760   }
 761 
 762   // Step 7
 763   // Next, if C is a class rather than an interface, initialize it's super class and super
 764   // interfaces.
 765   if (!is_interface()) {
 766     Klass* super_klass = super();
 767     if (super_klass != NULL && super_klass->should_be_initialized()) {
 768       super_klass->initialize(THREAD);
 769     }
 770     // If C implements any interface that declares a non-static, concrete method,
 771     // the initialization of C triggers initialization of its super interfaces.
 772     // Only need to recurse if has_nonstatic_concrete_methods which includes declaring and
 773     // having a superinterface that declares, non-static, concrete methods
 774     if (!HAS_PENDING_EXCEPTION && has_nonstatic_concrete_methods()) {
 775       initialize_super_interfaces(THREAD);
 776     }
 777 
 778     // If any exceptions, complete abruptly, throwing the same exception as above.
 779     if (HAS_PENDING_EXCEPTION) {
 780       Handle e(THREAD, PENDING_EXCEPTION);
 781       CLEAR_PENDING_EXCEPTION;
 782       {
 783         EXCEPTION_MARK;
 784         // Locks object, set state, and notify all waiting threads
 785         set_initialization_state_and_notify(initialization_error, THREAD);
 786         CLEAR_PENDING_EXCEPTION;
 787       }
 788       DTRACE_CLASSINIT_PROBE_WAIT(super__failed, -1, wait);
 789       THROW_OOP(e());
 790     }
 791   }
 792 
 793 
 794   // Look for aot compiled methods for this klass, including class initializer.
 795   AOTLoader::load_for_klass(this, THREAD);
 796 
 797   // Step 8
 798   {
 799     assert(THREAD->is_Java_thread(), "non-JavaThread in initialize_impl");
 800     JavaThread* jt = (JavaThread*)THREAD;
 801     DTRACE_CLASSINIT_PROBE_WAIT(clinit, -1, wait);
 802     // Timer includes any side effects of class initialization (resolution,
 803     // etc), but not recursive entry into call_class_initializer().
 804     PerfClassTraceTime timer(ClassLoader::perf_class_init_time(),
 805                              ClassLoader::perf_class_init_selftime(),
 806                              ClassLoader::perf_classes_inited(),
 807                              jt->get_thread_stat()->perf_recursion_counts_addr(),
 808                              jt->get_thread_stat()->perf_timers_addr(),
 809                              PerfClassTraceTime::CLASS_CLINIT);
 810     call_class_initializer(THREAD);
 811   }
 812 
 813   // Step 9
 814   if (!HAS_PENDING_EXCEPTION) {
 815     set_initialization_state_and_notify(fully_initialized, CHECK);
 816     {
 817       debug_only(vtable().verify(tty, true);)
 818     }
 819   }
 820   else {
 821     // Step 10 and 11
 822     Handle e(THREAD, PENDING_EXCEPTION);
 823     CLEAR_PENDING_EXCEPTION;
 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       EXCEPTION_MARK;
 829       set_initialization_state_and_notify(initialization_error, THREAD);
 830       CLEAR_PENDING_EXCEPTION;   // ignore any exception thrown, class initialization error is thrown below
 831       // JVMTI has already reported the pending exception
 832       // JVMTI internal flag reset is needed in order to report ExceptionInInitializerError
 833       JvmtiExport::clear_detected_exception((JavaThread*)THREAD);
 834     }
 835     DTRACE_CLASSINIT_PROBE_WAIT(error, -1, wait);
 836     if (e->is_a(SystemDictionary::Error_klass())) {
 837       THROW_OOP(e());
 838     } else {
 839       JavaCallArguments args(e);
 840       THROW_ARG(vmSymbols::java_lang_ExceptionInInitializerError(),
 841                 vmSymbols::throwable_void_signature(),
 842                 &args);
 843     }
 844   }
 845   DTRACE_CLASSINIT_PROBE_WAIT(end, -1, wait);
 846 }
 847 
 848 
 849 void InstanceKlass::set_initialization_state_and_notify(ClassState state, TRAPS) {
 850   Handle h_init_lock(THREAD, init_lock());
 851   if (h_init_lock() != NULL) {
 852     ObjectLocker ol(h_init_lock, THREAD);
 853     set_init_state(state);
 854     fence_and_clear_init_lock();
 855     ol.notify_all(CHECK);
 856   } else {
 857     assert(h_init_lock() != NULL, "The initialization state should never be set twice");
 858     set_init_state(state);
 859   }
 860 }
 861 
 862 // The embedded _implementor field can only record one implementor.
 863 // When there are more than one implementors, the _implementor field
 864 // is set to the interface Klass* itself. Following are the possible
 865 // values for the _implementor field:
 866 //   NULL                  - no implementor
 867 //   implementor Klass*    - one implementor
 868 //   self                  - more than one implementor
 869 //
 870 // The _implementor field only exists for interfaces.
 871 void InstanceKlass::add_implementor(Klass* k) {
 872   assert(Compile_lock->owned_by_self(), "");
 873   assert(is_interface(), "not interface");
 874   // Filter out my subinterfaces.
 875   // (Note: Interfaces are never on the subklass list.)
 876   if (InstanceKlass::cast(k)->is_interface()) return;
 877 
 878   // Filter out subclasses whose supers already implement me.
 879   // (Note: CHA must walk subclasses of direct implementors
 880   // in order to locate indirect implementors.)
 881   Klass* sk = k->super();
 882   if (sk != NULL && InstanceKlass::cast(sk)->implements_interface(this))
 883     // We only need to check one immediate superclass, since the
 884     // implements_interface query looks at transitive_interfaces.
 885     // Any supers of the super have the same (or fewer) transitive_interfaces.
 886     return;
 887 
 888   Klass* ik = implementor();
 889   if (ik == NULL) {
 890     set_implementor(k);
 891   } else if (ik != this) {
 892     // There is already an implementor. Use itself as an indicator of
 893     // more than one implementors.
 894     set_implementor(this);
 895   }
 896 
 897   // The implementor also implements the transitive_interfaces
 898   for (int index = 0; index < local_interfaces()->length(); index++) {
 899     InstanceKlass::cast(local_interfaces()->at(index))->add_implementor(k);
 900   }
 901 }
 902 
 903 void InstanceKlass::init_implementor() {
 904   if (is_interface()) {
 905     set_implementor(NULL);
 906   }
 907 }
 908 
 909 
 910 void InstanceKlass::process_interfaces(Thread *thread) {
 911   // link this class into the implementors list of every interface it implements
 912   for (int i = local_interfaces()->length() - 1; i >= 0; i--) {
 913     assert(local_interfaces()->at(i)->is_klass(), "must be a klass");
 914     InstanceKlass* interf = InstanceKlass::cast(local_interfaces()->at(i));
 915     assert(interf->is_interface(), "expected interface");
 916     interf->add_implementor(this);
 917   }
 918 }
 919 
 920 bool InstanceKlass::can_be_primary_super_slow() const {
 921   if (is_interface())
 922     return false;
 923   else
 924     return Klass::can_be_primary_super_slow();
 925 }
 926 
 927 GrowableArray<Klass*>* InstanceKlass::compute_secondary_supers(int num_extra_slots) {
 928   // The secondaries are the implemented interfaces.
 929   Array<Klass*>* interfaces = transitive_interfaces();
 930   int num_secondaries = num_extra_slots + interfaces->length();
 931   if (num_secondaries == 0) {
 932     // Must share this for correct bootstrapping!
 933     set_secondary_supers(Universe::the_empty_klass_array());
 934     return NULL;
 935   } else if (num_extra_slots == 0) {
 936     // The secondary super list is exactly the same as the transitive interfaces.
 937     // Redefine classes has to be careful not to delete this!
 938     set_secondary_supers(interfaces);
 939     return NULL;
 940   } else {
 941     // Copy transitive interfaces to a temporary growable array to be constructed
 942     // into the secondary super list with extra slots.
 943     GrowableArray<Klass*>* secondaries = new GrowableArray<Klass*>(interfaces->length());
 944     for (int i = 0; i < interfaces->length(); i++) {
 945       secondaries->push(interfaces->at(i));
 946     }
 947     return secondaries;
 948   }
 949 }
 950 
 951 bool InstanceKlass::compute_is_subtype_of(Klass* k) {
 952   if (k->is_interface()) {
 953     return implements_interface(k);
 954   } else {
 955     return Klass::compute_is_subtype_of(k);
 956   }
 957 }
 958 
 959 bool InstanceKlass::implements_interface(Klass* k) const {
 960   if (this == k) return true;
 961   assert(k->is_interface(), "should be an interface class");
 962   for (int i = 0; i < transitive_interfaces()->length(); i++) {
 963     if (transitive_interfaces()->at(i) == k) {
 964       return true;
 965     }
 966   }
 967   return false;
 968 }
 969 
 970 bool InstanceKlass::is_same_or_direct_interface(Klass *k) const {
 971   // Verify direct super interface
 972   if (this == k) return true;
 973   assert(k->is_interface(), "should be an interface class");
 974   for (int i = 0; i < local_interfaces()->length(); i++) {
 975     if (local_interfaces()->at(i) == k) {
 976       return true;
 977     }
 978   }
 979   return false;
 980 }
 981 
 982 objArrayOop InstanceKlass::allocate_objArray(int n, int length, TRAPS) {
 983   if (length < 0) THROW_0(vmSymbols::java_lang_NegativeArraySizeException());
 984   if (length > arrayOopDesc::max_array_length(T_OBJECT)) {
 985     report_java_out_of_memory("Requested array size exceeds VM limit");
 986     JvmtiExport::post_array_size_exhausted();
 987     THROW_OOP_0(Universe::out_of_memory_error_array_size());
 988   }
 989   int size = objArrayOopDesc::object_size(length);
 990   Klass* ak = array_klass(n, CHECK_NULL);
 991   objArrayOop o =
 992     (objArrayOop)CollectedHeap::array_allocate(ak, size, length, CHECK_NULL);
 993   return o;
 994 }
 995 
 996 instanceOop InstanceKlass::register_finalizer(instanceOop i, TRAPS) {
 997   if (TraceFinalizerRegistration) {
 998     tty->print("Registered ");
 999     i->print_value_on(tty);
1000     tty->print_cr(" (" INTPTR_FORMAT ") as finalizable", p2i(i));
1001   }
1002   instanceHandle h_i(THREAD, i);
1003   // Pass the handle as argument, JavaCalls::call expects oop as jobjects
1004   JavaValue result(T_VOID);
1005   JavaCallArguments args(h_i);
1006   methodHandle mh (THREAD, Universe::finalizer_register_method());
1007   JavaCalls::call(&result, mh, &args, CHECK_NULL);
1008   return h_i();
1009 }
1010 
1011 instanceOop InstanceKlass::allocate_instance(TRAPS) {
1012   bool has_finalizer_flag = has_finalizer(); // Query before possible GC
1013   int size = size_helper();  // Query before forming handle.
1014 
1015   instanceOop i;
1016 
1017   i = (instanceOop)CollectedHeap::obj_allocate(this, size, CHECK_NULL);
1018   if (has_finalizer_flag && !RegisterFinalizersAtInit) {
1019     i = register_finalizer(i, CHECK_NULL);
1020   }
1021   return i;
1022 }
1023 
1024 void InstanceKlass::check_valid_for_instantiation(bool throwError, TRAPS) {
1025   if (is_interface() || is_abstract()) {
1026     ResourceMark rm(THREAD);
1027     THROW_MSG(throwError ? vmSymbols::java_lang_InstantiationError()
1028               : vmSymbols::java_lang_InstantiationException(), external_name());
1029   }
1030   if (this == SystemDictionary::Class_klass()) {
1031     ResourceMark rm(THREAD);
1032     THROW_MSG(throwError ? vmSymbols::java_lang_IllegalAccessError()
1033               : vmSymbols::java_lang_IllegalAccessException(), external_name());
1034   }
1035 }
1036 
1037 Klass* InstanceKlass::array_klass_impl(bool or_null, int n, TRAPS) {
1038   // Need load-acquire for lock-free read
1039   if (array_klasses_acquire() == NULL) {
1040     if (or_null) return NULL;
1041 
1042     ResourceMark rm;
1043     JavaThread *jt = (JavaThread *)THREAD;
1044     {
1045       // Atomic creation of array_klasses
1046       MutexLocker mc(Compile_lock, THREAD);   // for vtables
1047       MutexLocker ma(MultiArray_lock, THREAD);
1048 
1049       // Check if update has already taken place
1050       if (array_klasses() == NULL) {
1051         Klass*    k = ObjArrayKlass::allocate_objArray_klass(class_loader_data(), 1, this, CHECK_NULL);
1052         // use 'release' to pair with lock-free load
1053         release_set_array_klasses(k);
1054       }
1055     }
1056   }
1057   // _this will always be set at this point
1058   ObjArrayKlass* oak = (ObjArrayKlass*)array_klasses();
1059   if (or_null) {
1060     return oak->array_klass_or_null(n);
1061   }
1062   return oak->array_klass(n, THREAD);
1063 }
1064 
1065 Klass* InstanceKlass::array_klass_impl(bool or_null, TRAPS) {
1066   return array_klass_impl(or_null, 1, THREAD);
1067 }
1068 
1069 static int call_class_initializer_counter = 0;   // for debugging
1070 
1071 Method* InstanceKlass::class_initializer() const {
1072   Method* clinit = find_method(
1073       vmSymbols::class_initializer_name(), vmSymbols::void_method_signature());
1074   if (clinit != NULL && clinit->has_valid_initializer_flags()) {
1075     return clinit;
1076   }
1077   return NULL;
1078 }
1079 
1080 void InstanceKlass::call_class_initializer(TRAPS) {
1081   if (ReplayCompiles &&
1082       (ReplaySuppressInitializers == 1 ||
1083        (ReplaySuppressInitializers >= 2 && class_loader() != NULL))) {
1084     // Hide the existence of the initializer for the purpose of replaying the compile
1085     return;
1086   }
1087 
1088   methodHandle h_method(THREAD, class_initializer());
1089   assert(!is_initialized(), "we cannot initialize twice");
1090   LogTarget(Info, class, init) lt;
1091   if (lt.is_enabled()) {
1092     ResourceMark rm;
1093     LogStream ls(lt);
1094     ls.print("%d Initializing ", call_class_initializer_counter++);
1095     name()->print_value_on(&ls);
1096     ls.print_cr("%s (" INTPTR_FORMAT ")", h_method() == NULL ? "(no method)" : "", p2i(this));
1097   }
1098   if (h_method() != NULL) {
1099     JavaCallArguments args; // No arguments
1100     JavaValue result(T_VOID);
1101     JavaCalls::call(&result, h_method, &args, CHECK); // Static call (no args)
1102   }
1103 }
1104 
1105 
1106 void InstanceKlass::mask_for(const methodHandle& method, int bci,
1107   InterpreterOopMap* entry_for) {
1108   // Lazily create the _oop_map_cache at first request
1109   // Lock-free access requires load_ptr_acquire.
1110   OopMapCache* oop_map_cache =
1111       static_cast<OopMapCache*>(OrderAccess::load_ptr_acquire(&_oop_map_cache));
1112   if (oop_map_cache == NULL) {
1113     MutexLocker x(OopMapCacheAlloc_lock);
1114     // Check if _oop_map_cache was allocated while we were waiting for this lock
1115     if ((oop_map_cache = _oop_map_cache) == NULL) {
1116       oop_map_cache = new OopMapCache();
1117       // Ensure _oop_map_cache is stable, since it is examined without a lock
1118       OrderAccess::release_store_ptr(&_oop_map_cache, oop_map_cache);
1119     }
1120   }
1121   // _oop_map_cache is constant after init; lookup below does its own locking.
1122   oop_map_cache->lookup(method, bci, entry_for);
1123 }
1124 
1125 
1126 bool InstanceKlass::find_local_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
1127   for (JavaFieldStream fs(this); !fs.done(); fs.next()) {
1128     Symbol* f_name = fs.name();
1129     Symbol* f_sig  = fs.signature();
1130     if (f_name == name && f_sig == sig) {
1131       fd->reinitialize(const_cast<InstanceKlass*>(this), fs.index());
1132       return true;
1133     }
1134   }
1135   return false;
1136 }
1137 
1138 
1139 Klass* InstanceKlass::find_interface_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
1140   const int n = local_interfaces()->length();
1141   for (int i = 0; i < n; i++) {
1142     Klass* intf1 = local_interfaces()->at(i);
1143     assert(intf1->is_interface(), "just checking type");
1144     // search for field in current interface
1145     if (InstanceKlass::cast(intf1)->find_local_field(name, sig, fd)) {
1146       assert(fd->is_static(), "interface field must be static");
1147       return intf1;
1148     }
1149     // search for field in direct superinterfaces
1150     Klass* intf2 = InstanceKlass::cast(intf1)->find_interface_field(name, sig, fd);
1151     if (intf2 != NULL) return intf2;
1152   }
1153   // otherwise field lookup fails
1154   return NULL;
1155 }
1156 
1157 
1158 Klass* InstanceKlass::find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
1159   // search order according to newest JVM spec (5.4.3.2, p.167).
1160   // 1) search for field in current klass
1161   if (find_local_field(name, sig, fd)) {
1162     return const_cast<InstanceKlass*>(this);
1163   }
1164   // 2) search for field recursively in direct superinterfaces
1165   { Klass* intf = find_interface_field(name, sig, fd);
1166     if (intf != NULL) return intf;
1167   }
1168   // 3) apply field lookup recursively if superclass exists
1169   { Klass* supr = super();
1170     if (supr != NULL) return InstanceKlass::cast(supr)->find_field(name, sig, fd);
1171   }
1172   // 4) otherwise field lookup fails
1173   return NULL;
1174 }
1175 
1176 
1177 Klass* InstanceKlass::find_field(Symbol* name, Symbol* sig, bool is_static, fieldDescriptor* fd) const {
1178   // search order according to newest JVM spec (5.4.3.2, p.167).
1179   // 1) search for field in current klass
1180   if (find_local_field(name, sig, fd)) {
1181     if (fd->is_static() == is_static) return const_cast<InstanceKlass*>(this);
1182   }
1183   // 2) search for field recursively in direct superinterfaces
1184   if (is_static) {
1185     Klass* intf = find_interface_field(name, sig, fd);
1186     if (intf != NULL) return intf;
1187   }
1188   // 3) apply field lookup recursively if superclass exists
1189   { Klass* supr = super();
1190     if (supr != NULL) return InstanceKlass::cast(supr)->find_field(name, sig, is_static, fd);
1191   }
1192   // 4) otherwise field lookup fails
1193   return NULL;
1194 }
1195 
1196 
1197 bool InstanceKlass::find_local_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const {
1198   for (JavaFieldStream fs(this); !fs.done(); fs.next()) {
1199     if (fs.offset() == offset) {
1200       fd->reinitialize(const_cast<InstanceKlass*>(this), fs.index());
1201       if (fd->is_static() == is_static) return true;
1202     }
1203   }
1204   return false;
1205 }
1206 
1207 
1208 bool InstanceKlass::find_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const {
1209   Klass* klass = const_cast<InstanceKlass*>(this);
1210   while (klass != NULL) {
1211     if (InstanceKlass::cast(klass)->find_local_field_from_offset(offset, is_static, fd)) {
1212       return true;
1213     }
1214     klass = klass->super();
1215   }
1216   return false;
1217 }
1218 
1219 
1220 void InstanceKlass::methods_do(void f(Method* method)) {
1221   // Methods aren't stable until they are loaded.  This can be read outside
1222   // a lock through the ClassLoaderData for profiling
1223   if (!is_loaded()) {
1224     return;
1225   }
1226 
1227   int len = methods()->length();
1228   for (int index = 0; index < len; index++) {
1229     Method* m = methods()->at(index);
1230     assert(m->is_method(), "must be method");
1231     f(m);
1232   }
1233 }
1234 
1235 
1236 void InstanceKlass::do_local_static_fields(FieldClosure* cl) {
1237   for (JavaFieldStream fs(this); !fs.done(); fs.next()) {
1238     if (fs.access_flags().is_static()) {
1239       fieldDescriptor& fd = fs.field_descriptor();
1240       cl->do_field(&fd);
1241     }
1242   }
1243 }
1244 
1245 
1246 void InstanceKlass::do_local_static_fields(void f(fieldDescriptor*, Handle, TRAPS), Handle mirror, TRAPS) {
1247   for (JavaFieldStream fs(this); !fs.done(); fs.next()) {
1248     if (fs.access_flags().is_static()) {
1249       fieldDescriptor& fd = fs.field_descriptor();
1250       f(&fd, mirror, CHECK);
1251     }
1252   }
1253 }
1254 
1255 
1256 static int compare_fields_by_offset(int* a, int* b) {
1257   return a[0] - b[0];
1258 }
1259 
1260 void InstanceKlass::do_nonstatic_fields(FieldClosure* cl) {
1261   InstanceKlass* super = superklass();
1262   if (super != NULL) {
1263     super->do_nonstatic_fields(cl);
1264   }
1265   fieldDescriptor fd;
1266   int length = java_fields_count();
1267   // In DebugInfo nonstatic fields are sorted by offset.
1268   int* fields_sorted = NEW_C_HEAP_ARRAY(int, 2*(length+1), mtClass);
1269   int j = 0;
1270   for (int i = 0; i < length; i += 1) {
1271     fd.reinitialize(this, i);
1272     if (!fd.is_static()) {
1273       fields_sorted[j + 0] = fd.offset();
1274       fields_sorted[j + 1] = i;
1275       j += 2;
1276     }
1277   }
1278   if (j > 0) {
1279     length = j;
1280     // _sort_Fn is defined in growableArray.hpp.
1281     qsort(fields_sorted, length/2, 2*sizeof(int), (_sort_Fn)compare_fields_by_offset);
1282     for (int i = 0; i < length; i += 2) {
1283       fd.reinitialize(this, fields_sorted[i + 1]);
1284       assert(!fd.is_static() && fd.offset() == fields_sorted[i], "only nonstatic fields");
1285       cl->do_field(&fd);
1286     }
1287   }
1288   FREE_C_HEAP_ARRAY(int, fields_sorted);
1289 }
1290 
1291 
1292 void InstanceKlass::array_klasses_do(void f(Klass* k, TRAPS), TRAPS) {
1293   if (array_klasses() != NULL)
1294     ArrayKlass::cast(array_klasses())->array_klasses_do(f, THREAD);
1295 }
1296 
1297 void InstanceKlass::array_klasses_do(void f(Klass* k)) {
1298   if (array_klasses() != NULL)
1299     ArrayKlass::cast(array_klasses())->array_klasses_do(f);
1300 }
1301 
1302 #ifdef ASSERT
1303 static int linear_search(const Array<Method*>* methods,
1304                          const Symbol* name,
1305                          const Symbol* signature) {
1306   const int len = methods->length();
1307   for (int index = 0; index < len; index++) {
1308     const Method* const m = methods->at(index);
1309     assert(m->is_method(), "must be method");
1310     if (m->signature() == signature && m->name() == name) {
1311        return index;
1312     }
1313   }
1314   return -1;
1315 }
1316 #endif
1317 
1318 static int binary_search(const Array<Method*>* methods, const Symbol* name) {
1319   int len = methods->length();
1320   // methods are sorted, so do binary search
1321   int l = 0;
1322   int h = len - 1;
1323   while (l <= h) {
1324     int mid = (l + h) >> 1;
1325     Method* m = methods->at(mid);
1326     assert(m->is_method(), "must be method");
1327     int res = m->name()->fast_compare(name);
1328     if (res == 0) {
1329       return mid;
1330     } else if (res < 0) {
1331       l = mid + 1;
1332     } else {
1333       h = mid - 1;
1334     }
1335   }
1336   return -1;
1337 }
1338 
1339 // find_method looks up the name/signature in the local methods array
1340 Method* InstanceKlass::find_method(const Symbol* name,
1341                                    const Symbol* signature) const {
1342   return find_method_impl(name, signature, find_overpass, find_static, find_private);
1343 }
1344 
1345 Method* InstanceKlass::find_method_impl(const Symbol* name,
1346                                         const Symbol* signature,
1347                                         OverpassLookupMode overpass_mode,
1348                                         StaticLookupMode static_mode,
1349                                         PrivateLookupMode private_mode) const {
1350   return InstanceKlass::find_method_impl(methods(),
1351                                          name,
1352                                          signature,
1353                                          overpass_mode,
1354                                          static_mode,
1355                                          private_mode);
1356 }
1357 
1358 // find_instance_method looks up the name/signature in the local methods array
1359 // and skips over static methods
1360 Method* InstanceKlass::find_instance_method(const Array<Method*>* methods,
1361                                             const Symbol* name,
1362                                             const Symbol* signature) {
1363   Method* const meth = InstanceKlass::find_method_impl(methods,
1364                                                  name,
1365                                                  signature,
1366                                                  find_overpass,
1367                                                  skip_static,
1368                                                  find_private);
1369   assert(((meth == NULL) || !meth->is_static()),
1370     "find_instance_method should have skipped statics");
1371   return meth;
1372 }
1373 
1374 // find_instance_method looks up the name/signature in the local methods array
1375 // and skips over static methods
1376 Method* InstanceKlass::find_instance_method(const Symbol* name, const Symbol* signature) const {
1377   return InstanceKlass::find_instance_method(methods(), name, signature);
1378 }
1379 
1380 // Find looks up the name/signature in the local methods array
1381 // and filters on the overpass, static and private flags
1382 // This returns the first one found
1383 // note that the local methods array can have up to one overpass, one static
1384 // and one instance (private or not) with the same name/signature
1385 Method* InstanceKlass::find_local_method(const Symbol* name,
1386                                          const Symbol* signature,
1387                                          OverpassLookupMode overpass_mode,
1388                                          StaticLookupMode static_mode,
1389                                          PrivateLookupMode private_mode) const {
1390   return InstanceKlass::find_method_impl(methods(),
1391                                          name,
1392                                          signature,
1393                                          overpass_mode,
1394                                          static_mode,
1395                                          private_mode);
1396 }
1397 
1398 // Find looks up the name/signature in the local methods array
1399 // and filters on the overpass, static and private flags
1400 // This returns the first one found
1401 // note that the local methods array can have up to one overpass, one static
1402 // and one instance (private or not) with the same name/signature
1403 Method* InstanceKlass::find_local_method(const Array<Method*>* methods,
1404                                          const Symbol* name,
1405                                          const Symbol* signature,
1406                                          OverpassLookupMode overpass_mode,
1407                                          StaticLookupMode static_mode,
1408                                          PrivateLookupMode private_mode) {
1409   return InstanceKlass::find_method_impl(methods,
1410                                          name,
1411                                          signature,
1412                                          overpass_mode,
1413                                          static_mode,
1414                                          private_mode);
1415 }
1416 
1417 Method* InstanceKlass::find_method(const Array<Method*>* methods,
1418                                    const Symbol* name,
1419                                    const Symbol* signature) {
1420   return InstanceKlass::find_method_impl(methods,
1421                                          name,
1422                                          signature,
1423                                          find_overpass,
1424                                          find_static,
1425                                          find_private);
1426 }
1427 
1428 Method* InstanceKlass::find_method_impl(const Array<Method*>* methods,
1429                                         const Symbol* name,
1430                                         const Symbol* signature,
1431                                         OverpassLookupMode overpass_mode,
1432                                         StaticLookupMode static_mode,
1433                                         PrivateLookupMode private_mode) {
1434   int hit = find_method_index(methods, name, signature, overpass_mode, static_mode, private_mode);
1435   return hit >= 0 ? methods->at(hit): NULL;
1436 }
1437 
1438 // true if method matches signature and conforms to skipping_X conditions.
1439 static bool method_matches(const Method* m,
1440                            const Symbol* signature,
1441                            bool skipping_overpass,
1442                            bool skipping_static,
1443                            bool skipping_private) {
1444   return ((m->signature() == signature) &&
1445     (!skipping_overpass || !m->is_overpass()) &&
1446     (!skipping_static || !m->is_static()) &&
1447     (!skipping_private || !m->is_private()));
1448 }
1449 
1450 // Used directly for default_methods to find the index into the
1451 // default_vtable_indices, and indirectly by find_method
1452 // find_method_index looks in the local methods array to return the index
1453 // of the matching name/signature. If, overpass methods are being ignored,
1454 // the search continues to find a potential non-overpass match.  This capability
1455 // is important during method resolution to prefer a static method, for example,
1456 // over an overpass method.
1457 // There is the possibility in any _method's array to have the same name/signature
1458 // for a static method, an overpass method and a local instance method
1459 // To correctly catch a given method, the search criteria may need
1460 // to explicitly skip the other two. For local instance methods, it
1461 // is often necessary to skip private methods
1462 int InstanceKlass::find_method_index(const Array<Method*>* methods,
1463                                      const Symbol* name,
1464                                      const Symbol* signature,
1465                                      OverpassLookupMode overpass_mode,
1466                                      StaticLookupMode static_mode,
1467                                      PrivateLookupMode private_mode) {
1468   const bool skipping_overpass = (overpass_mode == skip_overpass);
1469   const bool skipping_static = (static_mode == skip_static);
1470   const bool skipping_private = (private_mode == skip_private);
1471   const int hit = binary_search(methods, name);
1472   if (hit != -1) {
1473     const Method* const m = methods->at(hit);
1474 
1475     // Do linear search to find matching signature.  First, quick check
1476     // for common case, ignoring overpasses if requested.
1477     if (method_matches(m, signature, skipping_overpass, skipping_static, skipping_private)) {
1478           return hit;
1479     }
1480 
1481     // search downwards through overloaded methods
1482     int i;
1483     for (i = hit - 1; i >= 0; --i) {
1484         const Method* const m = methods->at(i);
1485         assert(m->is_method(), "must be method");
1486         if (m->name() != name) {
1487           break;
1488         }
1489         if (method_matches(m, signature, skipping_overpass, skipping_static, skipping_private)) {
1490           return i;
1491         }
1492     }
1493     // search upwards
1494     for (i = hit + 1; i < methods->length(); ++i) {
1495         const Method* const m = methods->at(i);
1496         assert(m->is_method(), "must be method");
1497         if (m->name() != name) {
1498           break;
1499         }
1500         if (method_matches(m, signature, skipping_overpass, skipping_static, skipping_private)) {
1501           return i;
1502         }
1503     }
1504     // not found
1505 #ifdef ASSERT
1506     const int index = (skipping_overpass || skipping_static || skipping_private) ? -1 :
1507       linear_search(methods, name, signature);
1508     assert(-1 == index, "binary search should have found entry %d", index);
1509 #endif
1510   }
1511   return -1;
1512 }
1513 
1514 int InstanceKlass::find_method_by_name(const Symbol* name, int* end) const {
1515   return find_method_by_name(methods(), name, end);
1516 }
1517 
1518 int InstanceKlass::find_method_by_name(const Array<Method*>* methods,
1519                                        const Symbol* name,
1520                                        int* end_ptr) {
1521   assert(end_ptr != NULL, "just checking");
1522   int start = binary_search(methods, name);
1523   int end = start + 1;
1524   if (start != -1) {
1525     while (start - 1 >= 0 && (methods->at(start - 1))->name() == name) --start;
1526     while (end < methods->length() && (methods->at(end))->name() == name) ++end;
1527     *end_ptr = end;
1528     return start;
1529   }
1530   return -1;
1531 }
1532 
1533 // uncached_lookup_method searches both the local class methods array and all
1534 // superclasses methods arrays, skipping any overpass methods in superclasses.
1535 Method* InstanceKlass::uncached_lookup_method(const Symbol* name,
1536                                               const Symbol* signature,
1537                                               OverpassLookupMode overpass_mode) const {
1538   OverpassLookupMode overpass_local_mode = overpass_mode;
1539   const Klass* klass = this;
1540   while (klass != NULL) {
1541     Method* const method = InstanceKlass::cast(klass)->find_method_impl(name,
1542                                                                         signature,
1543                                                                         overpass_local_mode,
1544                                                                         find_static,
1545                                                                         find_private);
1546     if (method != NULL) {
1547       return method;
1548     }
1549     klass = klass->super();
1550     overpass_local_mode = skip_overpass;   // Always ignore overpass methods in superclasses
1551   }
1552   return NULL;
1553 }
1554 
1555 #ifdef ASSERT
1556 // search through class hierarchy and return true if this class or
1557 // one of the superclasses was redefined
1558 bool InstanceKlass::has_redefined_this_or_super() const {
1559   const Klass* klass = this;
1560   while (klass != NULL) {
1561     if (InstanceKlass::cast(klass)->has_been_redefined()) {
1562       return true;
1563     }
1564     klass = klass->super();
1565   }
1566   return false;
1567 }
1568 #endif
1569 
1570 // lookup a method in the default methods list then in all transitive interfaces
1571 // Do NOT return private or static methods
1572 Method* InstanceKlass::lookup_method_in_ordered_interfaces(Symbol* name,
1573                                                          Symbol* signature) const {
1574   Method* m = NULL;
1575   if (default_methods() != NULL) {
1576     m = find_method(default_methods(), name, signature);
1577   }
1578   // Look up interfaces
1579   if (m == NULL) {
1580     m = lookup_method_in_all_interfaces(name, signature, find_defaults);
1581   }
1582   return m;
1583 }
1584 
1585 // lookup a method in all the interfaces that this class implements
1586 // Do NOT return private or static methods, new in JDK8 which are not externally visible
1587 // They should only be found in the initial InterfaceMethodRef
1588 Method* InstanceKlass::lookup_method_in_all_interfaces(Symbol* name,
1589                                                        Symbol* signature,
1590                                                        DefaultsLookupMode defaults_mode) const {
1591   Array<Klass*>* all_ifs = transitive_interfaces();
1592   int num_ifs = all_ifs->length();
1593   InstanceKlass *ik = NULL;
1594   for (int i = 0; i < num_ifs; i++) {
1595     ik = InstanceKlass::cast(all_ifs->at(i));
1596     Method* m = ik->lookup_method(name, signature);
1597     if (m != NULL && m->is_public() && !m->is_static() &&
1598         ((defaults_mode != skip_defaults) || !m->is_default_method())) {
1599       return m;
1600     }
1601   }
1602   return NULL;
1603 }
1604 
1605 /* jni_id_for_impl for jfieldIds only */
1606 JNIid* InstanceKlass::jni_id_for_impl(int offset) {
1607   MutexLocker ml(JfieldIdCreation_lock);
1608   // Retry lookup after we got the lock
1609   JNIid* probe = jni_ids() == NULL ? NULL : jni_ids()->find(offset);
1610   if (probe == NULL) {
1611     // Slow case, allocate new static field identifier
1612     probe = new JNIid(this, offset, jni_ids());
1613     set_jni_ids(probe);
1614   }
1615   return probe;
1616 }
1617 
1618 
1619 /* jni_id_for for jfieldIds only */
1620 JNIid* InstanceKlass::jni_id_for(int offset) {
1621   JNIid* probe = jni_ids() == NULL ? NULL : jni_ids()->find(offset);
1622   if (probe == NULL) {
1623     probe = jni_id_for_impl(offset);
1624   }
1625   return probe;
1626 }
1627 
1628 u2 InstanceKlass::enclosing_method_data(int offset) const {
1629   const Array<jushort>* const inner_class_list = inner_classes();
1630   if (inner_class_list == NULL) {
1631     return 0;
1632   }
1633   const int length = inner_class_list->length();
1634   if (length % inner_class_next_offset == 0) {
1635     return 0;
1636   }
1637   const int index = length - enclosing_method_attribute_size;
1638   assert(offset < enclosing_method_attribute_size, "invalid offset");
1639   return inner_class_list->at(index + offset);
1640 }
1641 
1642 void InstanceKlass::set_enclosing_method_indices(u2 class_index,
1643                                                  u2 method_index) {
1644   Array<jushort>* inner_class_list = inner_classes();
1645   assert (inner_class_list != NULL, "_inner_classes list is not set up");
1646   int length = inner_class_list->length();
1647   if (length % inner_class_next_offset == enclosing_method_attribute_size) {
1648     int index = length - enclosing_method_attribute_size;
1649     inner_class_list->at_put(
1650       index + enclosing_method_class_index_offset, class_index);
1651     inner_class_list->at_put(
1652       index + enclosing_method_method_index_offset, method_index);
1653   }
1654 }
1655 
1656 // Lookup or create a jmethodID.
1657 // This code is called by the VMThread and JavaThreads so the
1658 // locking has to be done very carefully to avoid deadlocks
1659 // and/or other cache consistency problems.
1660 //
1661 jmethodID InstanceKlass::get_jmethod_id(const methodHandle& method_h) {
1662   size_t idnum = (size_t)method_h->method_idnum();
1663   jmethodID* jmeths = methods_jmethod_ids_acquire();
1664   size_t length = 0;
1665   jmethodID id = NULL;
1666 
1667   // We use a double-check locking idiom here because this cache is
1668   // performance sensitive. In the normal system, this cache only
1669   // transitions from NULL to non-NULL which is safe because we use
1670   // release_set_methods_jmethod_ids() to advertise the new cache.
1671   // A partially constructed cache should never be seen by a racing
1672   // thread. We also use release_store_ptr() to save a new jmethodID
1673   // in the cache so a partially constructed jmethodID should never be
1674   // seen either. Cache reads of existing jmethodIDs proceed without a
1675   // lock, but cache writes of a new jmethodID requires uniqueness and
1676   // creation of the cache itself requires no leaks so a lock is
1677   // generally acquired in those two cases.
1678   //
1679   // If the RedefineClasses() API has been used, then this cache can
1680   // grow and we'll have transitions from non-NULL to bigger non-NULL.
1681   // Cache creation requires no leaks and we require safety between all
1682   // cache accesses and freeing of the old cache so a lock is generally
1683   // acquired when the RedefineClasses() API has been used.
1684 
1685   if (jmeths != NULL) {
1686     // the cache already exists
1687     if (!idnum_can_increment()) {
1688       // the cache can't grow so we can just get the current values
1689       get_jmethod_id_length_value(jmeths, idnum, &length, &id);
1690     } else {
1691       // cache can grow so we have to be more careful
1692       if (Threads::number_of_threads() == 0 ||
1693           SafepointSynchronize::is_at_safepoint()) {
1694         // we're single threaded or at a safepoint - no locking needed
1695         get_jmethod_id_length_value(jmeths, idnum, &length, &id);
1696       } else {
1697         MutexLocker ml(JmethodIdCreation_lock);
1698         get_jmethod_id_length_value(jmeths, idnum, &length, &id);
1699       }
1700     }
1701   }
1702   // implied else:
1703   // we need to allocate a cache so default length and id values are good
1704 
1705   if (jmeths == NULL ||   // no cache yet
1706       length <= idnum ||  // cache is too short
1707       id == NULL) {       // cache doesn't contain entry
1708 
1709     // This function can be called by the VMThread so we have to do all
1710     // things that might block on a safepoint before grabbing the lock.
1711     // Otherwise, we can deadlock with the VMThread or have a cache
1712     // consistency issue. These vars keep track of what we might have
1713     // to free after the lock is dropped.
1714     jmethodID  to_dealloc_id     = NULL;
1715     jmethodID* to_dealloc_jmeths = NULL;
1716 
1717     // may not allocate new_jmeths or use it if we allocate it
1718     jmethodID* new_jmeths = NULL;
1719     if (length <= idnum) {
1720       // allocate a new cache that might be used
1721       size_t size = MAX2(idnum+1, (size_t)idnum_allocated_count());
1722       new_jmeths = NEW_C_HEAP_ARRAY(jmethodID, size+1, mtClass);
1723       memset(new_jmeths, 0, (size+1)*sizeof(jmethodID));
1724       // cache size is stored in element[0], other elements offset by one
1725       new_jmeths[0] = (jmethodID)size;
1726     }
1727 
1728     // allocate a new jmethodID that might be used
1729     jmethodID new_id = NULL;
1730     if (method_h->is_old() && !method_h->is_obsolete()) {
1731       // The method passed in is old (but not obsolete), we need to use the current version
1732       Method* current_method = method_with_idnum((int)idnum);
1733       assert(current_method != NULL, "old and but not obsolete, so should exist");
1734       new_id = Method::make_jmethod_id(class_loader_data(), current_method);
1735     } else {
1736       // It is the current version of the method or an obsolete method,
1737       // use the version passed in
1738       new_id = Method::make_jmethod_id(class_loader_data(), method_h());
1739     }
1740 
1741     if (Threads::number_of_threads() == 0 ||
1742         SafepointSynchronize::is_at_safepoint()) {
1743       // we're single threaded or at a safepoint - no locking needed
1744       id = get_jmethod_id_fetch_or_update(idnum, new_id, new_jmeths,
1745                                           &to_dealloc_id, &to_dealloc_jmeths);
1746     } else {
1747       MutexLocker ml(JmethodIdCreation_lock);
1748       id = get_jmethod_id_fetch_or_update(idnum, new_id, new_jmeths,
1749                                           &to_dealloc_id, &to_dealloc_jmeths);
1750     }
1751 
1752     // The lock has been dropped so we can free resources.
1753     // Free up either the old cache or the new cache if we allocated one.
1754     if (to_dealloc_jmeths != NULL) {
1755       FreeHeap(to_dealloc_jmeths);
1756     }
1757     // free up the new ID since it wasn't needed
1758     if (to_dealloc_id != NULL) {
1759       Method::destroy_jmethod_id(class_loader_data(), to_dealloc_id);
1760     }
1761   }
1762   return id;
1763 }
1764 
1765 // Figure out how many jmethodIDs haven't been allocated, and make
1766 // sure space for them is pre-allocated.  This makes getting all
1767 // method ids much, much faster with classes with more than 8
1768 // methods, and has a *substantial* effect on performance with jvmti
1769 // code that loads all jmethodIDs for all classes.
1770 void InstanceKlass::ensure_space_for_methodids(int start_offset) {
1771   int new_jmeths = 0;
1772   int length = methods()->length();
1773   for (int index = start_offset; index < length; index++) {
1774     Method* m = methods()->at(index);
1775     jmethodID id = m->find_jmethod_id_or_null();
1776     if (id == NULL) {
1777       new_jmeths++;
1778     }
1779   }
1780   if (new_jmeths != 0) {
1781     Method::ensure_jmethod_ids(class_loader_data(), new_jmeths);
1782   }
1783 }
1784 
1785 // Common code to fetch the jmethodID from the cache or update the
1786 // cache with the new jmethodID. This function should never do anything
1787 // that causes the caller to go to a safepoint or we can deadlock with
1788 // the VMThread or have cache consistency issues.
1789 //
1790 jmethodID InstanceKlass::get_jmethod_id_fetch_or_update(
1791             size_t idnum, jmethodID new_id,
1792             jmethodID* new_jmeths, jmethodID* to_dealloc_id_p,
1793             jmethodID** to_dealloc_jmeths_p) {
1794   assert(new_id != NULL, "sanity check");
1795   assert(to_dealloc_id_p != NULL, "sanity check");
1796   assert(to_dealloc_jmeths_p != NULL, "sanity check");
1797   assert(Threads::number_of_threads() == 0 ||
1798          SafepointSynchronize::is_at_safepoint() ||
1799          JmethodIdCreation_lock->owned_by_self(), "sanity check");
1800 
1801   // reacquire the cache - we are locked, single threaded or at a safepoint
1802   jmethodID* jmeths = methods_jmethod_ids_acquire();
1803   jmethodID  id     = NULL;
1804   size_t     length = 0;
1805 
1806   if (jmeths == NULL ||                         // no cache yet
1807       (length = (size_t)jmeths[0]) <= idnum) {  // cache is too short
1808     if (jmeths != NULL) {
1809       // copy any existing entries from the old cache
1810       for (size_t index = 0; index < length; index++) {
1811         new_jmeths[index+1] = jmeths[index+1];
1812       }
1813       *to_dealloc_jmeths_p = jmeths;  // save old cache for later delete
1814     }
1815     release_set_methods_jmethod_ids(jmeths = new_jmeths);
1816   } else {
1817     // fetch jmethodID (if any) from the existing cache
1818     id = jmeths[idnum+1];
1819     *to_dealloc_jmeths_p = new_jmeths;  // save new cache for later delete
1820   }
1821   if (id == NULL) {
1822     // No matching jmethodID in the existing cache or we have a new
1823     // cache or we just grew the cache. This cache write is done here
1824     // by the first thread to win the foot race because a jmethodID
1825     // needs to be unique once it is generally available.
1826     id = new_id;
1827 
1828     // The jmethodID cache can be read while unlocked so we have to
1829     // make sure the new jmethodID is complete before installing it
1830     // in the cache.
1831     OrderAccess::release_store_ptr(&jmeths[idnum+1], id);
1832   } else {
1833     *to_dealloc_id_p = new_id; // save new id for later delete
1834   }
1835   return id;
1836 }
1837 
1838 
1839 // Common code to get the jmethodID cache length and the jmethodID
1840 // value at index idnum if there is one.
1841 //
1842 void InstanceKlass::get_jmethod_id_length_value(jmethodID* cache,
1843        size_t idnum, size_t *length_p, jmethodID* id_p) {
1844   assert(cache != NULL, "sanity check");
1845   assert(length_p != NULL, "sanity check");
1846   assert(id_p != NULL, "sanity check");
1847 
1848   // cache size is stored in element[0], other elements offset by one
1849   *length_p = (size_t)cache[0];
1850   if (*length_p <= idnum) {  // cache is too short
1851     *id_p = NULL;
1852   } else {
1853     *id_p = cache[idnum+1];  // fetch jmethodID (if any)
1854   }
1855 }
1856 
1857 
1858 // Lookup a jmethodID, NULL if not found.  Do no blocking, no allocations, no handles
1859 jmethodID InstanceKlass::jmethod_id_or_null(Method* method) {
1860   size_t idnum = (size_t)method->method_idnum();
1861   jmethodID* jmeths = methods_jmethod_ids_acquire();
1862   size_t length;                                // length assigned as debugging crumb
1863   jmethodID id = NULL;
1864   if (jmeths != NULL &&                         // If there is a cache
1865       (length = (size_t)jmeths[0]) > idnum) {   // and if it is long enough,
1866     id = jmeths[idnum+1];                       // Look up the id (may be NULL)
1867   }
1868   return id;
1869 }
1870 
1871 inline DependencyContext InstanceKlass::dependencies() {
1872   DependencyContext dep_context(&_dep_context);
1873   return dep_context;
1874 }
1875 
1876 int InstanceKlass::mark_dependent_nmethods(KlassDepChange& changes) {
1877   return dependencies().mark_dependent_nmethods(changes);
1878 }
1879 
1880 void InstanceKlass::add_dependent_nmethod(nmethod* nm) {
1881   dependencies().add_dependent_nmethod(nm);
1882 }
1883 
1884 void InstanceKlass::remove_dependent_nmethod(nmethod* nm, bool delete_immediately) {
1885   dependencies().remove_dependent_nmethod(nm, delete_immediately);
1886 }
1887 
1888 #ifndef PRODUCT
1889 void InstanceKlass::print_dependent_nmethods(bool verbose) {
1890   dependencies().print_dependent_nmethods(verbose);
1891 }
1892 
1893 bool InstanceKlass::is_dependent_nmethod(nmethod* nm) {
1894   return dependencies().is_dependent_nmethod(nm);
1895 }
1896 #endif //PRODUCT
1897 
1898 void InstanceKlass::clean_weak_instanceklass_links(BoolObjectClosure* is_alive) {
1899   clean_implementors_list(is_alive);
1900   clean_method_data(is_alive);
1901 
1902   // Since GC iterates InstanceKlasses sequentially, it is safe to remove stale entries here.
1903   DependencyContext dep_context(&_dep_context);
1904   dep_context.expunge_stale_entries();
1905 }
1906 
1907 void InstanceKlass::clean_implementors_list(BoolObjectClosure* is_alive) {
1908   assert(class_loader_data()->is_alive(is_alive), "this klass should be live");
1909   if (is_interface()) {
1910     if (ClassUnloading) {
1911       Klass* impl = implementor();
1912       if (impl != NULL) {
1913         if (!impl->is_loader_alive(is_alive)) {
1914           // remove this guy
1915           Klass** klass = adr_implementor();
1916           assert(klass != NULL, "null klass");
1917           if (klass != NULL) {
1918             *klass = NULL;
1919           }
1920         }
1921       }
1922     }
1923   }
1924 }
1925 
1926 void InstanceKlass::clean_method_data(BoolObjectClosure* is_alive) {
1927   for (int m = 0; m < methods()->length(); m++) {
1928     MethodData* mdo = methods()->at(m)->method_data();
1929     if (mdo != NULL) {
1930       mdo->clean_method_data(is_alive);
1931     }
1932   }
1933 }
1934 
1935 bool InstanceKlass::supers_have_passed_fingerprint_checks() {
1936   if (java_super() != NULL && !java_super()->has_passed_fingerprint_check()) {
1937     ResourceMark rm;
1938     log_trace(class, fingerprint)("%s : super %s not fingerprinted", external_name(), java_super()->external_name());
1939     return false;
1940   }
1941 
1942   Array<Klass*>* local_interfaces = this->local_interfaces();
1943   if (local_interfaces != NULL) {
1944     int length = local_interfaces->length();
1945     for (int i = 0; i < length; i++) {
1946       InstanceKlass* intf = InstanceKlass::cast(local_interfaces->at(i));
1947       if (!intf->has_passed_fingerprint_check()) {
1948         ResourceMark rm;
1949         log_trace(class, fingerprint)("%s : interface %s not fingerprinted", external_name(), intf->external_name());
1950         return false;
1951       }
1952     }
1953   }
1954 
1955   return true;
1956 }
1957 
1958 bool InstanceKlass::should_store_fingerprint() {
1959 #if INCLUDE_AOT
1960   // We store the fingerprint into the InstanceKlass only in the following 2 cases:
1961   if (CalculateClassFingerprint) {
1962     // (1) We are running AOT to generate a shared library.
1963     return true;
1964   }
1965   if (DumpSharedSpaces) {
1966     // (2) We are running -Xshare:dump to create a shared archive
1967     return true;
1968   }
1969 #endif
1970 
1971   // In all other cases we might set the _misc_has_passed_fingerprint_check bit,
1972   // but do not store the 64-bit fingerprint to save space.
1973   return false;
1974 }
1975 
1976 bool InstanceKlass::has_stored_fingerprint() const {
1977 #if INCLUDE_AOT
1978   return should_store_fingerprint() || is_shared();
1979 #else
1980   return false;
1981 #endif
1982 }
1983 
1984 uint64_t InstanceKlass::get_stored_fingerprint() const {
1985   address adr = adr_fingerprint();
1986   if (adr != NULL) {
1987     return (uint64_t)Bytes::get_native_u8(adr); // adr may not be 64-bit aligned
1988   }
1989   return 0;
1990 }
1991 
1992 void InstanceKlass::store_fingerprint(uint64_t fingerprint) {
1993   address adr = adr_fingerprint();
1994   if (adr != NULL) {
1995     Bytes::put_native_u8(adr, (u8)fingerprint); // adr may not be 64-bit aligned
1996 
1997     ResourceMark rm;
1998     log_trace(class, fingerprint)("stored as " PTR64_FORMAT " for class %s", fingerprint, external_name());
1999   }
2000 }
2001 
2002 void InstanceKlass::metaspace_pointers_do(MetaspaceClosure* it) {
2003   Klass::metaspace_pointers_do(it);
2004 
2005   if (log_is_enabled(Trace, cds)) {
2006     ResourceMark rm;
2007     log_trace(cds)("Iter(InstanceKlass): %p (%s)", this, external_name());
2008   }
2009 
2010   it->push(&_annotations);
2011   it->push((Klass**)&_array_klasses);
2012   it->push(&_constants);
2013   it->push(&_inner_classes);
2014   it->push(&_array_name);
2015 #if INCLUDE_JVMTI
2016   it->push(&_previous_versions);
2017 #endif
2018   it->push(&_methods);
2019   it->push(&_default_methods);
2020   it->push(&_local_interfaces);
2021   it->push(&_transitive_interfaces);
2022   it->push(&_method_ordering);
2023   it->push(&_default_vtable_indices);
2024   it->push(&_fields);
2025 
2026   if (itable_length() > 0) {
2027     itableOffsetEntry* ioe = (itableOffsetEntry*)start_of_itable();
2028     int method_table_offset_in_words = ioe->offset()/wordSize;
2029     int nof_interfaces = (method_table_offset_in_words - itable_offset_in_words())
2030                          / itableOffsetEntry::size();
2031 
2032     for (int i = 0; i < nof_interfaces; i ++, ioe ++) {
2033       if (ioe->interface_klass() != NULL) {
2034         it->push(ioe->interface_klass_addr());
2035         itableMethodEntry* ime = ioe->first_method_entry(this);
2036         int n = klassItable::method_count_for_interface(ioe->interface_klass());
2037         for (int index = 0; index < n; index ++) {
2038           it->push(ime[index].method_addr());
2039         }
2040       }
2041     }
2042   }
2043 }
2044 
2045 void InstanceKlass::remove_unshareable_info() {
2046   Klass::remove_unshareable_info();
2047 
2048   if (is_in_error_state()) {
2049     // Classes are attempted to link during dumping and may fail,
2050     // but these classes are still in the dictionary and class list in CLD.
2051     // Check in_error state first because in_error is > linked state, so
2052     // is_linked() is true.
2053     // If there's a linking error, there is nothing else to remove.
2054     return;
2055   }
2056 
2057   // Unlink the class
2058   if (is_linked()) {
2059     unlink_class();
2060   }
2061   init_implementor();
2062 
2063   constants()->remove_unshareable_info();
2064 
2065   for (int i = 0; i < methods()->length(); i++) {
2066     Method* m = methods()->at(i);
2067     m->remove_unshareable_info();
2068   }
2069 
2070   // These are not allocated from metaspace, but they should should all be empty
2071   // during dump time, so we don't need to worry about them in InstanceKlass::metaspace_pointers_do().
2072   guarantee(_source_debug_extension == NULL, "must be");
2073   guarantee(_oop_map_cache == NULL, "must be");
2074   guarantee(_init_thread == NULL, "must be");
2075   guarantee(_oop_map_cache == NULL, "must be");
2076   guarantee(_jni_ids == NULL, "must be");
2077   guarantee(_methods_jmethod_ids == NULL, "must be");
2078   guarantee(_dep_context == DependencyContext::EMPTY, "must be");
2079   guarantee(_osr_nmethods_head == NULL, "must be");
2080 
2081 #if INCLUDE_JVMTI
2082   guarantee(_breakpoints == NULL, "must be");
2083   guarantee(_previous_versions == NULL, "must be");
2084 #endif
2085 }
2086 
2087 static void restore_unshareable_in_class(Klass* k, TRAPS) {
2088   // Array classes have null protection domain.
2089   // --> see ArrayKlass::complete_create_array_klass()
2090   k->restore_unshareable_info(ClassLoaderData::the_null_class_loader_data(), Handle(), CHECK);
2091 }
2092 
2093 void InstanceKlass::restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS) {
2094   set_package(loader_data, CHECK);
2095   Klass::restore_unshareable_info(loader_data, protection_domain, CHECK);
2096 
2097   Array<Method*>* methods = this->methods();
2098   int num_methods = methods->length();
2099   for (int index2 = 0; index2 < num_methods; ++index2) {
2100     methodHandle m(THREAD, methods->at(index2));
2101     m->restore_unshareable_info(CHECK);
2102   }
2103   if (JvmtiExport::has_redefined_a_class()) {
2104     // Reinitialize vtable because RedefineClasses may have changed some
2105     // entries in this vtable for super classes so the CDS vtable might
2106     // point to old or obsolete entries.  RedefineClasses doesn't fix up
2107     // vtables in the shared system dictionary, only the main one.
2108     // It also redefines the itable too so fix that too.
2109     ResourceMark rm(THREAD);
2110     vtable().initialize_vtable(false, CHECK);
2111     itable().initialize_itable(false, CHECK);
2112   }
2113 
2114   // restore constant pool resolved references
2115   constants()->restore_unshareable_info(CHECK);
2116 
2117   array_klasses_do(restore_unshareable_in_class, CHECK);
2118 }
2119 
2120 // returns true IFF is_in_error_state() has been changed as a result of this call.
2121 bool InstanceKlass::check_sharing_error_state() {
2122   assert(DumpSharedSpaces, "should only be called during dumping");
2123   bool old_state = is_in_error_state();
2124 
2125   if (!is_in_error_state()) {
2126     bool bad = false;
2127     for (InstanceKlass* sup = java_super(); sup; sup = sup->java_super()) {
2128       if (sup->is_in_error_state()) {
2129         bad = true;
2130         break;
2131       }
2132     }
2133     if (!bad) {
2134       Array<Klass*>* interfaces = transitive_interfaces();
2135       for (int i = 0; i < interfaces->length(); i++) {
2136         Klass* iface = interfaces->at(i);
2137         if (InstanceKlass::cast(iface)->is_in_error_state()) {
2138           bad = true;
2139           break;
2140         }
2141       }
2142     }
2143 
2144     if (bad) {
2145       set_in_error_state();
2146     }
2147   }
2148 
2149   return (old_state != is_in_error_state());
2150 }
2151 
2152 #if INCLUDE_JVMTI
2153 static void clear_all_breakpoints(Method* m) {
2154   m->clear_all_breakpoints();
2155 }
2156 #endif
2157 
2158 void InstanceKlass::notify_unload_class(InstanceKlass* ik) {
2159   // notify the debugger
2160   if (JvmtiExport::should_post_class_unload()) {
2161     JvmtiExport::post_class_unload(ik);
2162   }
2163 
2164   // notify ClassLoadingService of class unload
2165   ClassLoadingService::notify_class_unloaded(ik);
2166 }
2167 
2168 void InstanceKlass::release_C_heap_structures(InstanceKlass* ik) {
2169   // Clean up C heap
2170   ik->release_C_heap_structures();
2171   ik->constants()->release_C_heap_structures();
2172 }
2173 
2174 void InstanceKlass::release_C_heap_structures() {
2175   // Can't release the constant pool here because the constant pool can be
2176   // deallocated separately from the InstanceKlass for default methods and
2177   // redefine classes.
2178 
2179   // Deallocate oop map cache
2180   if (_oop_map_cache != NULL) {
2181     delete _oop_map_cache;
2182     _oop_map_cache = NULL;
2183   }
2184 
2185   // Deallocate JNI identifiers for jfieldIDs
2186   JNIid::deallocate(jni_ids());
2187   set_jni_ids(NULL);
2188 
2189   jmethodID* jmeths = methods_jmethod_ids_acquire();
2190   if (jmeths != (jmethodID*)NULL) {
2191     release_set_methods_jmethod_ids(NULL);
2192     FreeHeap(jmeths);
2193   }
2194 
2195   // Release dependencies.
2196   // It is desirable to use DC::remove_all_dependents() here, but, unfortunately,
2197   // it is not safe (see JDK-8143408). The problem is that the klass dependency
2198   // context can contain live dependencies, since there's a race between nmethod &
2199   // klass unloading. If the klass is dead when nmethod unloading happens, relevant
2200   // dependencies aren't removed from the context associated with the class (see
2201   // nmethod::flush_dependencies). It ends up during klass unloading as seemingly
2202   // live dependencies pointing to unloaded nmethods and causes a crash in
2203   // DC::remove_all_dependents() when it touches unloaded nmethod.
2204   dependencies().wipe();
2205 
2206 #if INCLUDE_JVMTI
2207   // Deallocate breakpoint records
2208   if (breakpoints() != 0x0) {
2209     methods_do(clear_all_breakpoints);
2210     assert(breakpoints() == 0x0, "should have cleared breakpoints");
2211   }
2212 
2213   // deallocate the cached class file
2214   if (_cached_class_file != NULL && !MetaspaceShared::is_in_shared_space(_cached_class_file)) {
2215     os::free(_cached_class_file);
2216     _cached_class_file = NULL;
2217   }
2218 #endif
2219 
2220   // Decrement symbol reference counts associated with the unloaded class.
2221   if (_name != NULL) _name->decrement_refcount();
2222   // unreference array name derived from this class name (arrays of an unloaded
2223   // class can't be referenced anymore).
2224   if (_array_name != NULL)  _array_name->decrement_refcount();
2225   if (_source_debug_extension != NULL) FREE_C_HEAP_ARRAY(char, _source_debug_extension);
2226 
2227   assert(_total_instanceKlass_count >= 1, "Sanity check");
2228   Atomic::dec(&_total_instanceKlass_count);
2229 }
2230 
2231 void InstanceKlass::set_source_debug_extension(const char* array, int length) {
2232   if (array == NULL) {
2233     _source_debug_extension = NULL;
2234   } else {
2235     // Adding one to the attribute length in order to store a null terminator
2236     // character could cause an overflow because the attribute length is
2237     // already coded with an u4 in the classfile, but in practice, it's
2238     // unlikely to happen.
2239     assert((length+1) > length, "Overflow checking");
2240     char* sde = NEW_C_HEAP_ARRAY(char, (length + 1), mtClass);
2241     for (int i = 0; i < length; i++) {
2242       sde[i] = array[i];
2243     }
2244     sde[length] = '\0';
2245     _source_debug_extension = sde;
2246   }
2247 }
2248 
2249 address InstanceKlass::static_field_addr(int offset) {
2250   return (address)(offset + InstanceMirrorKlass::offset_of_static_fields() + cast_from_oop<intptr_t>(java_mirror()));
2251 }
2252 
2253 
2254 const char* InstanceKlass::signature_name() const {
2255   int hash_len = 0;
2256   char hash_buf[40];
2257 
2258   // If this is an anonymous class, append a hash to make the name unique
2259   if (is_anonymous()) {
2260     intptr_t hash = (java_mirror() != NULL) ? java_mirror()->identity_hash() : 0;
2261     jio_snprintf(hash_buf, sizeof(hash_buf), "/" UINTX_FORMAT, (uintx)hash);
2262     hash_len = (int)strlen(hash_buf);
2263   }
2264 
2265   // Get the internal name as a c string
2266   const char* src = (const char*) (name()->as_C_string());
2267   const int src_length = (int)strlen(src);
2268 
2269   char* dest = NEW_RESOURCE_ARRAY(char, src_length + hash_len + 3);
2270 
2271   // Add L as type indicator
2272   int dest_index = 0;
2273   dest[dest_index++] = 'L';
2274 
2275   // Add the actual class name
2276   for (int src_index = 0; src_index < src_length; ) {
2277     dest[dest_index++] = src[src_index++];
2278   }
2279 
2280   // If we have a hash, append it
2281   for (int hash_index = 0; hash_index < hash_len; ) {
2282     dest[dest_index++] = hash_buf[hash_index++];
2283   }
2284 
2285   // Add the semicolon and the NULL
2286   dest[dest_index++] = ';';
2287   dest[dest_index] = '\0';
2288   return dest;
2289 }
2290 
2291 // Used to obtain the package name from a fully qualified class name.
2292 Symbol* InstanceKlass::package_from_name(const Symbol* name, TRAPS) {
2293   if (name == NULL) {
2294     return NULL;
2295   } else {
2296     if (name->utf8_length() <= 0) {
2297       return NULL;
2298     }
2299     ResourceMark rm;
2300     const char* package_name = ClassLoader::package_from_name((const char*) name->as_C_string());
2301     if (package_name == NULL) {
2302       return NULL;
2303     }
2304     Symbol* pkg_name = SymbolTable::new_symbol(package_name, THREAD);
2305     return pkg_name;
2306   }
2307 }
2308 
2309 ModuleEntry* InstanceKlass::module() const {
2310   if (!in_unnamed_package()) {
2311     return _package_entry->module();
2312   }
2313   const Klass* host = host_klass();
2314   if (host == NULL) {
2315     return class_loader_data()->unnamed_module();
2316   }
2317   return host->class_loader_data()->unnamed_module();
2318 }
2319 
2320 void InstanceKlass::set_package(ClassLoaderData* loader_data, TRAPS) {
2321 
2322   // ensure java/ packages only loaded by boot or platform builtin loaders
2323   Handle class_loader(THREAD, loader_data->class_loader());
2324   check_prohibited_package(name(), class_loader, CHECK);
2325 
2326   TempNewSymbol pkg_name = package_from_name(name(), CHECK);
2327 
2328   if (pkg_name != NULL && loader_data != NULL) {
2329 
2330     // Find in class loader's package entry table.
2331     _package_entry = loader_data->packages()->lookup_only(pkg_name);
2332 
2333     // If the package name is not found in the loader's package
2334     // entry table, it is an indication that the package has not
2335     // been defined. Consider it defined within the unnamed module.
2336     if (_package_entry == NULL) {
2337       ResourceMark rm;
2338 
2339       if (!ModuleEntryTable::javabase_defined()) {
2340         // Before java.base is defined during bootstrapping, define all packages in
2341         // the java.base module.  If a non-java.base package is erroneously placed
2342         // in the java.base module it will be caught later when java.base
2343         // is defined by ModuleEntryTable::verify_javabase_packages check.
2344         assert(ModuleEntryTable::javabase_moduleEntry() != NULL, JAVA_BASE_NAME " module is NULL");
2345         _package_entry = loader_data->packages()->lookup(pkg_name, ModuleEntryTable::javabase_moduleEntry());
2346       } else {
2347         assert(loader_data->unnamed_module() != NULL, "unnamed module is NULL");
2348         _package_entry = loader_data->packages()->lookup(pkg_name,
2349                                                          loader_data->unnamed_module());
2350       }
2351 
2352       // A package should have been successfully created
2353       assert(_package_entry != NULL, "Package entry for class %s not found, loader %s",
2354              name()->as_C_string(), loader_data->loader_name());
2355     }
2356 
2357     if (log_is_enabled(Debug, module)) {
2358       ResourceMark rm;
2359       ModuleEntry* m = _package_entry->module();
2360       log_trace(module)("Setting package: class: %s, package: %s, loader: %s, module: %s",
2361                         external_name(),
2362                         pkg_name->as_C_string(),
2363                         loader_data->loader_name(),
2364                         (m->is_named() ? m->name()->as_C_string() : UNNAMED_MODULE));
2365     }
2366   } else {
2367     ResourceMark rm;
2368     log_trace(module)("Setting package: class: %s, package: unnamed, loader: %s, module: %s",
2369                       external_name(),
2370                       (loader_data != NULL) ? loader_data->loader_name() : "NULL",
2371                       UNNAMED_MODULE);
2372   }
2373 }
2374 
2375 
2376 // different versions of is_same_class_package
2377 
2378 bool InstanceKlass::is_same_class_package(const Klass* class2) const {
2379   oop classloader1 = this->class_loader();
2380   PackageEntry* classpkg1 = this->package();
2381   if (class2->is_objArray_klass()) {
2382     class2 = ObjArrayKlass::cast(class2)->bottom_klass();
2383   }
2384 
2385   oop classloader2;
2386   PackageEntry* classpkg2;
2387   if (class2->is_instance_klass()) {
2388     classloader2 = class2->class_loader();
2389     classpkg2 = class2->package();
2390   } else {
2391     assert(class2->is_typeArray_klass(), "should be type array");
2392     classloader2 = NULL;
2393     classpkg2 = NULL;
2394   }
2395 
2396   // Same package is determined by comparing class loader
2397   // and package entries. Both must be the same. This rule
2398   // applies even to classes that are defined in the unnamed
2399   // package, they still must have the same class loader.
2400   if ((classloader1 == classloader2) && (classpkg1 == classpkg2)) {
2401     return true;
2402   }
2403 
2404   return false;
2405 }
2406 
2407 // return true if this class and other_class are in the same package. Classloader
2408 // and classname information is enough to determine a class's package
2409 bool InstanceKlass::is_same_class_package(oop other_class_loader,
2410                                           const Symbol* other_class_name) const {
2411   if (class_loader() != other_class_loader) {
2412     return false;
2413   }
2414   if (name()->fast_compare(other_class_name) == 0) {
2415      return true;
2416   }
2417 
2418   {
2419     ResourceMark rm;
2420 
2421     bool bad_class_name = false;
2422     const char* other_pkg =
2423       ClassLoader::package_from_name((const char*) other_class_name->as_C_string(), &bad_class_name);
2424     if (bad_class_name) {
2425       return false;
2426     }
2427     // Check that package_from_name() returns NULL, not "", if there is no package.
2428     assert(other_pkg == NULL || strlen(other_pkg) > 0, "package name is empty string");
2429 
2430     const Symbol* const this_package_name =
2431       this->package() != NULL ? this->package()->name() : NULL;
2432 
2433     if (this_package_name == NULL || other_pkg == NULL) {
2434       // One of the two doesn't have a package.  Only return true if the other
2435       // one also doesn't have a package.
2436       return (const char*)this_package_name == other_pkg;
2437     }
2438 
2439     // Check if package is identical
2440     return this_package_name->equals(other_pkg);
2441   }
2442 }
2443 
2444 // Returns true iff super_method can be overridden by a method in targetclassname
2445 // See JLS 3rd edition 8.4.6.1
2446 // Assumes name-signature match
2447 // "this" is InstanceKlass of super_method which must exist
2448 // note that the InstanceKlass of the method in the targetclassname has not always been created yet
2449 bool InstanceKlass::is_override(const methodHandle& super_method, Handle targetclassloader, Symbol* targetclassname, TRAPS) {
2450    // Private methods can not be overridden
2451    if (super_method->is_private()) {
2452      return false;
2453    }
2454    // If super method is accessible, then override
2455    if ((super_method->is_protected()) ||
2456        (super_method->is_public())) {
2457      return true;
2458    }
2459    // Package-private methods are not inherited outside of package
2460    assert(super_method->is_package_private(), "must be package private");
2461    return(is_same_class_package(targetclassloader(), targetclassname));
2462 }
2463 
2464 // Only boot and platform class loaders can define classes in "java/" packages.
2465 void InstanceKlass::check_prohibited_package(Symbol* class_name,
2466                                              Handle class_loader,
2467                                              TRAPS) {
2468   if (!class_loader.is_null() &&
2469       !SystemDictionary::is_platform_class_loader(class_loader()) &&
2470       class_name != NULL) {
2471     ResourceMark rm(THREAD);
2472     char* name = class_name->as_C_string();
2473     if (strncmp(name, JAVAPKG, JAVAPKG_LEN) == 0 && name[JAVAPKG_LEN] == '/') {
2474       TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK);
2475       assert(pkg_name != NULL, "Error in parsing package name starting with 'java/'");
2476       name = pkg_name->as_C_string();
2477       const char* class_loader_name = SystemDictionary::loader_name(class_loader());
2478       StringUtils::replace_no_expand(name, "/", ".");
2479       const char* msg_text1 = "Class loader (instance of): ";
2480       const char* msg_text2 = " tried to load prohibited package name: ";
2481       size_t len = strlen(msg_text1) + strlen(class_loader_name) + strlen(msg_text2) + strlen(name) + 1;
2482       char* message = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, len);
2483       jio_snprintf(message, len, "%s%s%s%s", msg_text1, class_loader_name, msg_text2, name);
2484       THROW_MSG(vmSymbols::java_lang_SecurityException(), message);
2485     }
2486   }
2487   return;
2488 }
2489 
2490 // tell if two classes have the same enclosing class (at package level)
2491 bool InstanceKlass::is_same_package_member(const Klass* class2, TRAPS) const {
2492   if (class2 == this) return true;
2493   if (!class2->is_instance_klass())  return false;
2494 
2495   // must be in same package before we try anything else
2496   if (!is_same_class_package(class2))
2497     return false;
2498 
2499   // As long as there is an outer_this.getEnclosingClass,
2500   // shift the search outward.
2501   const InstanceKlass* outer_this = this;
2502   for (;;) {
2503     // As we walk along, look for equalities between outer_this and class2.
2504     // Eventually, the walks will terminate as outer_this stops
2505     // at the top-level class around the original class.
2506     bool ignore_inner_is_member;
2507     const Klass* next = outer_this->compute_enclosing_class(&ignore_inner_is_member,
2508                                                             CHECK_false);
2509     if (next == NULL)  break;
2510     if (next == class2)  return true;
2511     outer_this = InstanceKlass::cast(next);
2512   }
2513 
2514   // Now do the same for class2.
2515   const InstanceKlass* outer2 = InstanceKlass::cast(class2);
2516   for (;;) {
2517     bool ignore_inner_is_member;
2518     Klass* next = outer2->compute_enclosing_class(&ignore_inner_is_member,
2519                                                     CHECK_false);
2520     if (next == NULL)  break;
2521     // Might as well check the new outer against all available values.
2522     if (next == this)  return true;
2523     if (next == outer_this)  return true;
2524     outer2 = InstanceKlass::cast(next);
2525   }
2526 
2527   // If by this point we have not found an equality between the
2528   // two classes, we know they are in separate package members.
2529   return false;
2530 }
2531 
2532 bool InstanceKlass::find_inner_classes_attr(int* ooff, int* noff, TRAPS) const {
2533   constantPoolHandle i_cp(THREAD, constants());
2534   for (InnerClassesIterator iter(this); !iter.done(); iter.next()) {
2535     int ioff = iter.inner_class_info_index();
2536     if (ioff != 0) {
2537       // Check to see if the name matches the class we're looking for
2538       // before attempting to find the class.
2539       if (i_cp->klass_name_at_matches(this, ioff)) {
2540         Klass* inner_klass = i_cp->klass_at(ioff, CHECK_false);
2541         if (this == inner_klass) {
2542           *ooff = iter.outer_class_info_index();
2543           *noff = iter.inner_name_index();
2544           return true;
2545         }
2546       }
2547     }
2548   }
2549   return false;
2550 }
2551 
2552 InstanceKlass* InstanceKlass::compute_enclosing_class(bool* inner_is_member, TRAPS) const {
2553   InstanceKlass* outer_klass = NULL;
2554   *inner_is_member = false;
2555   int ooff = 0, noff = 0;
2556   bool has_inner_classes_attr = find_inner_classes_attr(&ooff, &noff, THREAD);
2557   if (has_inner_classes_attr) {
2558     constantPoolHandle i_cp(THREAD, constants());
2559     if (ooff != 0) {
2560       Klass* ok = i_cp->klass_at(ooff, CHECK_NULL);
2561       outer_klass = InstanceKlass::cast(ok);
2562       *inner_is_member = true;
2563     }
2564     if (NULL == outer_klass) {
2565       // It may be anonymous; try for that.
2566       int encl_method_class_idx = enclosing_method_class_index();
2567       if (encl_method_class_idx != 0) {
2568         Klass* ok = i_cp->klass_at(encl_method_class_idx, CHECK_NULL);
2569         outer_klass = InstanceKlass::cast(ok);
2570         *inner_is_member = false;
2571       }
2572     }
2573   }
2574 
2575   // If no inner class attribute found for this class.
2576   if (NULL == outer_klass) return NULL;
2577 
2578   // Throws an exception if outer klass has not declared k as an inner klass
2579   // We need evidence that each klass knows about the other, or else
2580   // the system could allow a spoof of an inner class to gain access rights.
2581   Reflection::check_for_inner_class(outer_klass, this, *inner_is_member, CHECK_NULL);
2582   return outer_klass;
2583 }
2584 
2585 jint InstanceKlass::compute_modifier_flags(TRAPS) const {
2586   jint access = access_flags().as_int();
2587 
2588   // But check if it happens to be member class.
2589   InnerClassesIterator iter(this);
2590   for (; !iter.done(); iter.next()) {
2591     int ioff = iter.inner_class_info_index();
2592     // Inner class attribute can be zero, skip it.
2593     // Strange but true:  JVM spec. allows null inner class refs.
2594     if (ioff == 0) continue;
2595 
2596     // only look at classes that are already loaded
2597     // since we are looking for the flags for our self.
2598     Symbol* inner_name = constants()->klass_name_at(ioff);
2599     if (name() == inner_name) {
2600       // This is really a member class.
2601       access = iter.inner_access_flags();
2602       break;
2603     }
2604   }
2605   // Remember to strip ACC_SUPER bit
2606   return (access & (~JVM_ACC_SUPER)) & JVM_ACC_WRITTEN_FLAGS;
2607 }
2608 
2609 jint InstanceKlass::jvmti_class_status() const {
2610   jint result = 0;
2611 
2612   if (is_linked()) {
2613     result |= JVMTI_CLASS_STATUS_VERIFIED | JVMTI_CLASS_STATUS_PREPARED;
2614   }
2615 
2616   if (is_initialized()) {
2617     assert(is_linked(), "Class status is not consistent");
2618     result |= JVMTI_CLASS_STATUS_INITIALIZED;
2619   }
2620   if (is_in_error_state()) {
2621     result |= JVMTI_CLASS_STATUS_ERROR;
2622   }
2623   return result;
2624 }
2625 
2626 Method* InstanceKlass::method_at_itable(Klass* holder, int index, TRAPS) {
2627   itableOffsetEntry* ioe = (itableOffsetEntry*)start_of_itable();
2628   int method_table_offset_in_words = ioe->offset()/wordSize;
2629   int nof_interfaces = (method_table_offset_in_words - itable_offset_in_words())
2630                        / itableOffsetEntry::size();
2631 
2632   for (int cnt = 0 ; ; cnt ++, ioe ++) {
2633     // If the interface isn't implemented by the receiver class,
2634     // the VM should throw IncompatibleClassChangeError.
2635     if (cnt >= nof_interfaces) {
2636       THROW_NULL(vmSymbols::java_lang_IncompatibleClassChangeError());
2637     }
2638 
2639     Klass* ik = ioe->interface_klass();
2640     if (ik == holder) break;
2641   }
2642 
2643   itableMethodEntry* ime = ioe->first_method_entry(this);
2644   Method* m = ime[index].method();
2645   if (m == NULL) {
2646     THROW_NULL(vmSymbols::java_lang_AbstractMethodError());
2647   }
2648   return m;
2649 }
2650 
2651 
2652 #if INCLUDE_JVMTI
2653 // update default_methods for redefineclasses for methods that are
2654 // not yet in the vtable due to concurrent subclass define and superinterface
2655 // redefinition
2656 // Note: those in the vtable, should have been updated via adjust_method_entries
2657 void InstanceKlass::adjust_default_methods(InstanceKlass* holder, bool* trace_name_printed) {
2658   // search the default_methods for uses of either obsolete or EMCP methods
2659   if (default_methods() != NULL) {
2660     for (int index = 0; index < default_methods()->length(); index ++) {
2661       Method* old_method = default_methods()->at(index);
2662       if (old_method == NULL || old_method->method_holder() != holder || !old_method->is_old()) {
2663         continue; // skip uninteresting entries
2664       }
2665       assert(!old_method->is_deleted(), "default methods may not be deleted");
2666 
2667       Method* new_method = holder->method_with_idnum(old_method->orig_method_idnum());
2668 
2669       assert(new_method != NULL, "method_with_idnum() should not be NULL");
2670       assert(old_method != new_method, "sanity check");
2671 
2672       default_methods()->at_put(index, new_method);
2673       if (log_is_enabled(Info, redefine, class, update)) {
2674         ResourceMark rm;
2675         if (!(*trace_name_printed)) {
2676           log_info(redefine, class, update)
2677             ("adjust: klassname=%s default methods from name=%s",
2678              external_name(), old_method->method_holder()->external_name());
2679           *trace_name_printed = true;
2680         }
2681         log_debug(redefine, class, update, vtables)
2682           ("default method update: %s(%s) ",
2683            new_method->name()->as_C_string(), new_method->signature()->as_C_string());
2684       }
2685     }
2686   }
2687 }
2688 #endif // INCLUDE_JVMTI
2689 
2690 // On-stack replacement stuff
2691 void InstanceKlass::add_osr_nmethod(nmethod* n) {
2692   // only one compilation can be active
2693   {
2694     // This is a short non-blocking critical region, so the no safepoint check is ok.
2695     MutexLockerEx ml(OsrList_lock, Mutex::_no_safepoint_check_flag);
2696     assert(n->is_osr_method(), "wrong kind of nmethod");
2697     n->set_osr_link(osr_nmethods_head());
2698     set_osr_nmethods_head(n);
2699     // Raise the highest osr level if necessary
2700     if (TieredCompilation) {
2701       Method* m = n->method();
2702       m->set_highest_osr_comp_level(MAX2(m->highest_osr_comp_level(), n->comp_level()));
2703     }
2704   }
2705 
2706   // Get rid of the osr methods for the same bci that have lower levels.
2707   if (TieredCompilation) {
2708     for (int l = CompLevel_limited_profile; l < n->comp_level(); l++) {
2709       nmethod *inv = lookup_osr_nmethod(n->method(), n->osr_entry_bci(), l, true);
2710       if (inv != NULL && inv->is_in_use()) {
2711         inv->make_not_entrant();
2712       }
2713     }
2714   }
2715 }
2716 
2717 // Remove osr nmethod from the list. Return true if found and removed.
2718 bool InstanceKlass::remove_osr_nmethod(nmethod* n) {
2719   // This is a short non-blocking critical region, so the no safepoint check is ok.
2720   MutexLockerEx ml(OsrList_lock, Mutex::_no_safepoint_check_flag);
2721   assert(n->is_osr_method(), "wrong kind of nmethod");
2722   nmethod* last = NULL;
2723   nmethod* cur  = osr_nmethods_head();
2724   int max_level = CompLevel_none;  // Find the max comp level excluding n
2725   Method* m = n->method();
2726   // Search for match
2727   bool found = false;
2728   while(cur != NULL && cur != n) {
2729     if (TieredCompilation && m == cur->method()) {
2730       // Find max level before n
2731       max_level = MAX2(max_level, cur->comp_level());
2732     }
2733     last = cur;
2734     cur = cur->osr_link();
2735   }
2736   nmethod* next = NULL;
2737   if (cur == n) {
2738     found = true;
2739     next = cur->osr_link();
2740     if (last == NULL) {
2741       // Remove first element
2742       set_osr_nmethods_head(next);
2743     } else {
2744       last->set_osr_link(next);
2745     }
2746   }
2747   n->set_osr_link(NULL);
2748   if (TieredCompilation) {
2749     cur = next;
2750     while (cur != NULL) {
2751       // Find max level after n
2752       if (m == cur->method()) {
2753         max_level = MAX2(max_level, cur->comp_level());
2754       }
2755       cur = cur->osr_link();
2756     }
2757     m->set_highest_osr_comp_level(max_level);
2758   }
2759   return found;
2760 }
2761 
2762 int InstanceKlass::mark_osr_nmethods(const Method* m) {
2763   // This is a short non-blocking critical region, so the no safepoint check is ok.
2764   MutexLockerEx ml(OsrList_lock, Mutex::_no_safepoint_check_flag);
2765   nmethod* osr = osr_nmethods_head();
2766   int found = 0;
2767   while (osr != NULL) {
2768     assert(osr->is_osr_method(), "wrong kind of nmethod found in chain");
2769     if (osr->method() == m) {
2770       osr->mark_for_deoptimization();
2771       found++;
2772     }
2773     osr = osr->osr_link();
2774   }
2775   return found;
2776 }
2777 
2778 nmethod* InstanceKlass::lookup_osr_nmethod(const Method* m, int bci, int comp_level, bool match_level) const {
2779   // This is a short non-blocking critical region, so the no safepoint check is ok.
2780   MutexLockerEx ml(OsrList_lock, Mutex::_no_safepoint_check_flag);
2781   nmethod* osr = osr_nmethods_head();
2782   nmethod* best = NULL;
2783   while (osr != NULL) {
2784     assert(osr->is_osr_method(), "wrong kind of nmethod found in chain");
2785     // There can be a time when a c1 osr method exists but we are waiting
2786     // for a c2 version. When c2 completes its osr nmethod we will trash
2787     // the c1 version and only be able to find the c2 version. However
2788     // while we overflow in the c1 code at back branches we don't want to
2789     // try and switch to the same code as we are already running
2790 
2791     if (osr->method() == m &&
2792         (bci == InvocationEntryBci || osr->osr_entry_bci() == bci)) {
2793       if (match_level) {
2794         if (osr->comp_level() == comp_level) {
2795           // Found a match - return it.
2796           return osr;
2797         }
2798       } else {
2799         if (best == NULL || (osr->comp_level() > best->comp_level())) {
2800           if (osr->comp_level() == CompLevel_highest_tier) {
2801             // Found the best possible - return it.
2802             return osr;
2803           }
2804           best = osr;
2805         }
2806       }
2807     }
2808     osr = osr->osr_link();
2809   }
2810   if (best != NULL && best->comp_level() >= comp_level && match_level == false) {
2811     return best;
2812   }
2813   return NULL;
2814 }
2815 
2816 // -----------------------------------------------------------------------------------------------------
2817 // Printing
2818 
2819 #ifndef PRODUCT
2820 
2821 #define BULLET  " - "
2822 
2823 static const char* state_names[] = {
2824   "allocated", "loaded", "linked", "being_initialized", "fully_initialized", "initialization_error"
2825 };
2826 
2827 static void print_vtable(intptr_t* start, int len, outputStream* st) {
2828   for (int i = 0; i < len; i++) {
2829     intptr_t e = start[i];
2830     st->print("%d : " INTPTR_FORMAT, i, e);
2831     if (e != 0 && ((Metadata*)e)->is_metaspace_object()) {
2832       st->print(" ");
2833       ((Metadata*)e)->print_value_on(st);
2834     }
2835     st->cr();
2836   }
2837 }
2838 
2839 static void print_vtable(vtableEntry* start, int len, outputStream* st) {
2840   return print_vtable(reinterpret_cast<intptr_t*>(start), len, st);
2841 }
2842 
2843 void InstanceKlass::print_on(outputStream* st) const {
2844   assert(is_klass(), "must be klass");
2845   Klass::print_on(st);
2846 
2847   st->print(BULLET"instance size:     %d", size_helper());                        st->cr();
2848   st->print(BULLET"klass size:        %d", size());                               st->cr();
2849   st->print(BULLET"access:            "); access_flags().print_on(st);            st->cr();
2850   st->print(BULLET"state:             "); st->print_cr("%s", state_names[_init_state]);
2851   st->print(BULLET"name:              "); name()->print_value_on(st);             st->cr();
2852   st->print(BULLET"super:             "); super()->print_value_on_maybe_null(st); st->cr();
2853   st->print(BULLET"sub:               ");
2854   Klass* sub = subklass();
2855   int n;
2856   for (n = 0; sub != NULL; n++, sub = sub->next_sibling()) {
2857     if (n < MaxSubklassPrintSize) {
2858       sub->print_value_on(st);
2859       st->print("   ");
2860     }
2861   }
2862   if (n >= MaxSubklassPrintSize) st->print("(" INTX_FORMAT " more klasses...)", n - MaxSubklassPrintSize);
2863   st->cr();
2864 
2865   if (is_interface()) {
2866     st->print_cr(BULLET"nof implementors:  %d", nof_implementors());
2867     if (nof_implementors() == 1) {
2868       st->print_cr(BULLET"implementor:    ");
2869       st->print("   ");
2870       implementor()->print_value_on(st);
2871       st->cr();
2872     }
2873   }
2874 
2875   st->print(BULLET"arrays:            "); array_klasses()->print_value_on_maybe_null(st); st->cr();
2876   st->print(BULLET"methods:           "); methods()->print_value_on(st);                  st->cr();
2877   if (Verbose || WizardMode) {
2878     Array<Method*>* method_array = methods();
2879     for (int i = 0; i < method_array->length(); i++) {
2880       st->print("%d : ", i); method_array->at(i)->print_value(); st->cr();
2881     }
2882   }
2883   st->print(BULLET"method ordering:   "); method_ordering()->print_value_on(st);      st->cr();
2884   st->print(BULLET"default_methods:   "); default_methods()->print_value_on(st);      st->cr();
2885   if (Verbose && default_methods() != NULL) {
2886     Array<Method*>* method_array = default_methods();
2887     for (int i = 0; i < method_array->length(); i++) {
2888       st->print("%d : ", i); method_array->at(i)->print_value(); st->cr();
2889     }
2890   }
2891   if (default_vtable_indices() != NULL) {
2892     st->print(BULLET"default vtable indices:   "); default_vtable_indices()->print_value_on(st);       st->cr();
2893   }
2894   st->print(BULLET"local interfaces:  "); local_interfaces()->print_value_on(st);      st->cr();
2895   st->print(BULLET"trans. interfaces: "); transitive_interfaces()->print_value_on(st); st->cr();
2896   st->print(BULLET"constants:         "); constants()->print_value_on(st);         st->cr();
2897   if (class_loader_data() != NULL) {
2898     st->print(BULLET"class loader data:  ");
2899     class_loader_data()->print_value_on(st);
2900     st->cr();
2901   }
2902   st->print(BULLET"host class:        "); host_klass()->print_value_on_maybe_null(st); st->cr();
2903   if (source_file_name() != NULL) {
2904     st->print(BULLET"source file:       ");
2905     source_file_name()->print_value_on(st);
2906     st->cr();
2907   }
2908   if (source_debug_extension() != NULL) {
2909     st->print(BULLET"source debug extension:       ");
2910     st->print("%s", source_debug_extension());
2911     st->cr();
2912   }
2913   st->print(BULLET"class annotations:       "); class_annotations()->print_value_on(st); st->cr();
2914   st->print(BULLET"class type annotations:  "); class_type_annotations()->print_value_on(st); st->cr();
2915   st->print(BULLET"field annotations:       "); fields_annotations()->print_value_on(st); st->cr();
2916   st->print(BULLET"field type annotations:  "); fields_type_annotations()->print_value_on(st); st->cr();
2917   {
2918     bool have_pv = false;
2919     // previous versions are linked together through the InstanceKlass
2920     for (InstanceKlass* pv_node = previous_versions();
2921          pv_node != NULL;
2922          pv_node = pv_node->previous_versions()) {
2923       if (!have_pv)
2924         st->print(BULLET"previous version:  ");
2925       have_pv = true;
2926       pv_node->constants()->print_value_on(st);
2927     }
2928     if (have_pv) st->cr();
2929   }
2930 
2931   if (generic_signature() != NULL) {
2932     st->print(BULLET"generic signature: ");
2933     generic_signature()->print_value_on(st);
2934     st->cr();
2935   }
2936   st->print(BULLET"inner classes:     "); inner_classes()->print_value_on(st);     st->cr();
2937   st->print(BULLET"java mirror:       "); java_mirror()->print_value_on(st);       st->cr();
2938   st->print(BULLET"vtable length      %d  (start addr: " INTPTR_FORMAT ")", vtable_length(), p2i(start_of_vtable())); st->cr();
2939   if (vtable_length() > 0 && (Verbose || WizardMode))  print_vtable(start_of_vtable(), vtable_length(), st);
2940   st->print(BULLET"itable length      %d (start addr: " INTPTR_FORMAT ")", itable_length(), p2i(start_of_itable())); st->cr();
2941   if (itable_length() > 0 && (Verbose || WizardMode))  print_vtable(start_of_itable(), itable_length(), st);
2942   st->print_cr(BULLET"---- static fields (%d words):", static_field_size());
2943   FieldPrinter print_static_field(st);
2944   ((InstanceKlass*)this)->do_local_static_fields(&print_static_field);
2945   st->print_cr(BULLET"---- non-static fields (%d words):", nonstatic_field_size());
2946   FieldPrinter print_nonstatic_field(st);
2947   InstanceKlass* ik = const_cast<InstanceKlass*>(this);
2948   ik->do_nonstatic_fields(&print_nonstatic_field);
2949 
2950   st->print(BULLET"non-static oop maps: ");
2951   OopMapBlock* map     = start_of_nonstatic_oop_maps();
2952   OopMapBlock* end_map = map + nonstatic_oop_map_count();
2953   while (map < end_map) {
2954     st->print("%d-%d ", map->offset(), map->offset() + heapOopSize*(map->count() - 1));
2955     map++;
2956   }
2957   st->cr();
2958 }
2959 
2960 #endif //PRODUCT
2961 
2962 void InstanceKlass::print_value_on(outputStream* st) const {
2963   assert(is_klass(), "must be klass");
2964   if (Verbose || WizardMode)  access_flags().print_on(st);
2965   name()->print_value_on(st);
2966 }
2967 
2968 #ifndef PRODUCT
2969 
2970 void FieldPrinter::do_field(fieldDescriptor* fd) {
2971   _st->print(BULLET);
2972    if (_obj == NULL) {
2973      fd->print_on(_st);
2974      _st->cr();
2975    } else {
2976      fd->print_on_for(_st, _obj);
2977      _st->cr();
2978    }
2979 }
2980 
2981 
2982 void InstanceKlass::oop_print_on(oop obj, outputStream* st) {
2983   Klass::oop_print_on(obj, st);
2984 
2985   if (this == SystemDictionary::String_klass()) {
2986     typeArrayOop value  = java_lang_String::value(obj);
2987     juint        length = java_lang_String::length(obj);
2988     if (value != NULL &&
2989         value->is_typeArray() &&
2990         length <= (juint) value->length()) {
2991       st->print(BULLET"string: ");
2992       java_lang_String::print(obj, st);
2993       st->cr();
2994       if (!WizardMode)  return;  // that is enough
2995     }
2996   }
2997 
2998   st->print_cr(BULLET"---- fields (total size %d words):", oop_size(obj));
2999   FieldPrinter print_field(st, obj);
3000   do_nonstatic_fields(&print_field);
3001 
3002   if (this == SystemDictionary::Class_klass()) {
3003     st->print(BULLET"signature: ");
3004     java_lang_Class::print_signature(obj, st);
3005     st->cr();
3006     Klass* mirrored_klass = java_lang_Class::as_Klass(obj);
3007     st->print(BULLET"fake entry for mirror: ");
3008     mirrored_klass->print_value_on_maybe_null(st);
3009     st->cr();
3010     Klass* array_klass = java_lang_Class::array_klass_acquire(obj);
3011     st->print(BULLET"fake entry for array: ");
3012     array_klass->print_value_on_maybe_null(st);
3013     st->cr();
3014     st->print_cr(BULLET"fake entry for oop_size: %d", java_lang_Class::oop_size(obj));
3015     st->print_cr(BULLET"fake entry for static_oop_field_count: %d", java_lang_Class::static_oop_field_count(obj));
3016     Klass* real_klass = java_lang_Class::as_Klass(obj);
3017     if (real_klass != NULL && real_klass->is_instance_klass()) {
3018       InstanceKlass::cast(real_klass)->do_local_static_fields(&print_field);
3019     }
3020   } else if (this == SystemDictionary::MethodType_klass()) {
3021     st->print(BULLET"signature: ");
3022     java_lang_invoke_MethodType::print_signature(obj, st);
3023     st->cr();
3024   }
3025 }
3026 
3027 #endif //PRODUCT
3028 
3029 void InstanceKlass::oop_print_value_on(oop obj, outputStream* st) {
3030   st->print("a ");
3031   name()->print_value_on(st);
3032   obj->print_address_on(st);
3033   if (this == SystemDictionary::String_klass()
3034       && java_lang_String::value(obj) != NULL) {
3035     ResourceMark rm;
3036     int len = java_lang_String::length(obj);
3037     int plen = (len < 24 ? len : 12);
3038     char* str = java_lang_String::as_utf8_string(obj, 0, plen);
3039     st->print(" = \"%s\"", str);
3040     if (len > plen)
3041       st->print("...[%d]", len);
3042   } else if (this == SystemDictionary::Class_klass()) {
3043     Klass* k = java_lang_Class::as_Klass(obj);
3044     st->print(" = ");
3045     if (k != NULL) {
3046       k->print_value_on(st);
3047     } else {
3048       const char* tname = type2name(java_lang_Class::primitive_type(obj));
3049       st->print("%s", tname ? tname : "type?");
3050     }
3051   } else if (this == SystemDictionary::MethodType_klass()) {
3052     st->print(" = ");
3053     java_lang_invoke_MethodType::print_signature(obj, st);
3054   } else if (java_lang_boxing_object::is_instance(obj)) {
3055     st->print(" = ");
3056     java_lang_boxing_object::print(obj, st);
3057   } else if (this == SystemDictionary::LambdaForm_klass()) {
3058     oop vmentry = java_lang_invoke_LambdaForm::vmentry(obj);
3059     if (vmentry != NULL) {
3060       st->print(" => ");
3061       vmentry->print_value_on(st);
3062     }
3063   } else if (this == SystemDictionary::MemberName_klass()) {
3064     Metadata* vmtarget = java_lang_invoke_MemberName::vmtarget(obj);
3065     if (vmtarget != NULL) {
3066       st->print(" = ");
3067       vmtarget->print_value_on(st);
3068     } else {
3069       java_lang_invoke_MemberName::clazz(obj)->print_value_on(st);
3070       st->print(".");
3071       java_lang_invoke_MemberName::name(obj)->print_value_on(st);
3072     }
3073   }
3074 }
3075 
3076 const char* InstanceKlass::internal_name() const {
3077   return external_name();
3078 }
3079 
3080 void InstanceKlass::print_class_load_logging(ClassLoaderData* loader_data,
3081                                              const char* module_name,
3082                                              const ClassFileStream* cfs) const {
3083   if (!log_is_enabled(Info, class, load)) {
3084     return;
3085   }
3086 
3087   ResourceMark rm;
3088   LogMessage(class, load) msg;
3089   stringStream info_stream;
3090 
3091   // Name and class hierarchy info
3092   info_stream.print("%s", external_name());
3093 
3094   // Source
3095   if (cfs != NULL) {
3096     if (cfs->source() != NULL) {
3097       if (module_name != NULL) {
3098         if (ClassLoader::is_jrt(cfs->source())) {
3099           info_stream.print(" source: jrt:/%s", module_name);
3100         } else {
3101           info_stream.print(" source: %s", cfs->source());
3102         }
3103       } else {
3104         info_stream.print(" source: %s", cfs->source());
3105       }
3106     } else if (loader_data == ClassLoaderData::the_null_class_loader_data()) {
3107       Thread* THREAD = Thread::current();
3108       Klass* caller =
3109             THREAD->is_Java_thread()
3110                 ? ((JavaThread*)THREAD)->security_get_caller_class(1)
3111                 : NULL;
3112       // caller can be NULL, for example, during a JVMTI VM_Init hook
3113       if (caller != NULL) {
3114         info_stream.print(" source: instance of %s", caller->external_name());
3115       } else {
3116         // source is unknown
3117       }
3118     } else {
3119       oop class_loader = loader_data->class_loader();
3120       info_stream.print(" source: %s", class_loader->klass()->external_name());
3121     }
3122   } else {
3123     info_stream.print(" source: shared objects file");
3124   }
3125 
3126   msg.info("%s", info_stream.as_string());
3127 
3128   if (log_is_enabled(Debug, class, load)) {
3129     stringStream debug_stream;
3130 
3131     // Class hierarchy info
3132     debug_stream.print(" klass: " INTPTR_FORMAT " super: " INTPTR_FORMAT,
3133                        p2i(this),  p2i(superklass()));
3134 
3135     // Interfaces
3136     if (local_interfaces() != NULL && local_interfaces()->length() > 0) {
3137       debug_stream.print(" interfaces:");
3138       int length = local_interfaces()->length();
3139       for (int i = 0; i < length; i++) {
3140         debug_stream.print(" " INTPTR_FORMAT,
3141                            p2i(InstanceKlass::cast(local_interfaces()->at(i))));
3142       }
3143     }
3144 
3145     // Class loader
3146     debug_stream.print(" loader: [");
3147     loader_data->print_value_on(&debug_stream);
3148     debug_stream.print("]");
3149 
3150     // Classfile checksum
3151     if (cfs) {
3152       debug_stream.print(" bytes: %d checksum: %08x",
3153                          cfs->length(),
3154                          ClassLoader::crc32(0, (const char*)cfs->buffer(),
3155                          cfs->length()));
3156     }
3157 
3158     msg.debug("%s", debug_stream.as_string());
3159   }
3160 }
3161 
3162 #if INCLUDE_SERVICES
3163 // Size Statistics
3164 void InstanceKlass::collect_statistics(KlassSizeStats *sz) const {
3165   Klass::collect_statistics(sz);
3166 
3167   sz->_inst_size  = wordSize * size_helper();
3168   sz->_vtab_bytes = wordSize * vtable_length();
3169   sz->_itab_bytes = wordSize * itable_length();
3170   sz->_nonstatic_oopmap_bytes = wordSize * nonstatic_oop_map_size();
3171 
3172   int n = 0;
3173   n += (sz->_methods_array_bytes         = sz->count_array(methods()));
3174   n += (sz->_method_ordering_bytes       = sz->count_array(method_ordering()));
3175   n += (sz->_local_interfaces_bytes      = sz->count_array(local_interfaces()));
3176   n += (sz->_transitive_interfaces_bytes = sz->count_array(transitive_interfaces()));
3177   n += (sz->_fields_bytes                = sz->count_array(fields()));
3178   n += (sz->_inner_classes_bytes         = sz->count_array(inner_classes()));
3179   sz->_ro_bytes += n;
3180 
3181   const ConstantPool* cp = constants();
3182   if (cp) {
3183     cp->collect_statistics(sz);
3184   }
3185 
3186   const Annotations* anno = annotations();
3187   if (anno) {
3188     anno->collect_statistics(sz);
3189   }
3190 
3191   const Array<Method*>* methods_array = methods();
3192   if (methods()) {
3193     for (int i = 0; i < methods_array->length(); i++) {
3194       Method* method = methods_array->at(i);
3195       if (method) {
3196         sz->_method_count ++;
3197         method->collect_statistics(sz);
3198       }
3199     }
3200   }
3201 }
3202 #endif // INCLUDE_SERVICES
3203 
3204 // Verification
3205 
3206 class VerifyFieldClosure: public OopClosure {
3207  protected:
3208   template <class T> void do_oop_work(T* p) {
3209     oop obj = oopDesc::load_decode_heap_oop(p);
3210     if (!oopDesc::is_oop_or_null(obj)) {
3211       tty->print_cr("Failed: " PTR_FORMAT " -> " PTR_FORMAT, p2i(p), p2i(obj));
3212       Universe::print_on(tty);
3213       guarantee(false, "boom");
3214     }
3215   }
3216  public:
3217   virtual void do_oop(oop* p)       { VerifyFieldClosure::do_oop_work(p); }
3218   virtual void do_oop(narrowOop* p) { VerifyFieldClosure::do_oop_work(p); }
3219 };
3220 
3221 void InstanceKlass::verify_on(outputStream* st) {
3222 #ifndef PRODUCT
3223   // Avoid redundant verifies, this really should be in product.
3224   if (_verify_count == Universe::verify_count()) return;
3225   _verify_count = Universe::verify_count();
3226 #endif
3227 
3228   // Verify Klass
3229   Klass::verify_on(st);
3230 
3231   // Verify that klass is present in ClassLoaderData
3232   guarantee(class_loader_data()->contains_klass(this),
3233             "this class isn't found in class loader data");
3234 
3235   // Verify vtables
3236   if (is_linked()) {
3237     // $$$ This used to be done only for m/s collections.  Doing it
3238     // always seemed a valid generalization.  (DLD -- 6/00)
3239     vtable().verify(st);
3240   }
3241 
3242   // Verify first subklass
3243   if (subklass() != NULL) {
3244     guarantee(subklass()->is_klass(), "should be klass");
3245   }
3246 
3247   // Verify siblings
3248   Klass* super = this->super();
3249   Klass* sib = next_sibling();
3250   if (sib != NULL) {
3251     if (sib == this) {
3252       fatal("subclass points to itself " PTR_FORMAT, p2i(sib));
3253     }
3254 
3255     guarantee(sib->is_klass(), "should be klass");
3256     guarantee(sib->super() == super, "siblings should have same superklass");
3257   }
3258 
3259   // Verify implementor fields
3260   Klass* im = implementor();
3261   if (im != NULL) {
3262     guarantee(is_interface(), "only interfaces should have implementor set");
3263     guarantee(im->is_klass(), "should be klass");
3264     guarantee(!im->is_interface() || im == this,
3265       "implementors cannot be interfaces");
3266   }
3267 
3268   // Verify local interfaces
3269   if (local_interfaces()) {
3270     Array<Klass*>* local_interfaces = this->local_interfaces();
3271     for (int j = 0; j < local_interfaces->length(); j++) {
3272       Klass* e = local_interfaces->at(j);
3273       guarantee(e->is_klass() && e->is_interface(), "invalid local interface");
3274     }
3275   }
3276 
3277   // Verify transitive interfaces
3278   if (transitive_interfaces() != NULL) {
3279     Array<Klass*>* transitive_interfaces = this->transitive_interfaces();
3280     for (int j = 0; j < transitive_interfaces->length(); j++) {
3281       Klass* e = transitive_interfaces->at(j);
3282       guarantee(e->is_klass() && e->is_interface(), "invalid transitive interface");
3283     }
3284   }
3285 
3286   // Verify methods
3287   if (methods() != NULL) {
3288     Array<Method*>* methods = this->methods();
3289     for (int j = 0; j < methods->length(); j++) {
3290       guarantee(methods->at(j)->is_method(), "non-method in methods array");
3291     }
3292     for (int j = 0; j < methods->length() - 1; j++) {
3293       Method* m1 = methods->at(j);
3294       Method* m2 = methods->at(j + 1);
3295       guarantee(m1->name()->fast_compare(m2->name()) <= 0, "methods not sorted correctly");
3296     }
3297   }
3298 
3299   // Verify method ordering
3300   if (method_ordering() != NULL) {
3301     Array<int>* method_ordering = this->method_ordering();
3302     int length = method_ordering->length();
3303     if (JvmtiExport::can_maintain_original_method_order() ||
3304         ((UseSharedSpaces || DumpSharedSpaces) && length != 0)) {
3305       guarantee(length == methods()->length(), "invalid method ordering length");
3306       jlong sum = 0;
3307       for (int j = 0; j < length; j++) {
3308         int original_index = method_ordering->at(j);
3309         guarantee(original_index >= 0, "invalid method ordering index");
3310         guarantee(original_index < length, "invalid method ordering index");
3311         sum += original_index;
3312       }
3313       // Verify sum of indices 0,1,...,length-1
3314       guarantee(sum == ((jlong)length*(length-1))/2, "invalid method ordering sum");
3315     } else {
3316       guarantee(length == 0, "invalid method ordering length");
3317     }
3318   }
3319 
3320   // Verify default methods
3321   if (default_methods() != NULL) {
3322     Array<Method*>* methods = this->default_methods();
3323     for (int j = 0; j < methods->length(); j++) {
3324       guarantee(methods->at(j)->is_method(), "non-method in methods array");
3325     }
3326     for (int j = 0; j < methods->length() - 1; j++) {
3327       Method* m1 = methods->at(j);
3328       Method* m2 = methods->at(j + 1);
3329       guarantee(m1->name()->fast_compare(m2->name()) <= 0, "methods not sorted correctly");
3330     }
3331   }
3332 
3333   // Verify JNI static field identifiers
3334   if (jni_ids() != NULL) {
3335     jni_ids()->verify(this);
3336   }
3337 
3338   // Verify other fields
3339   if (array_klasses() != NULL) {
3340     guarantee(array_klasses()->is_klass(), "should be klass");
3341   }
3342   if (constants() != NULL) {
3343     guarantee(constants()->is_constantPool(), "should be constant pool");
3344   }
3345   const Klass* host = host_klass();
3346   if (host != NULL) {
3347     guarantee(host->is_klass(), "should be klass");
3348   }
3349 }
3350 
3351 void InstanceKlass::oop_verify_on(oop obj, outputStream* st) {
3352   Klass::oop_verify_on(obj, st);
3353   VerifyFieldClosure blk;
3354   obj->oop_iterate_no_header(&blk);
3355 }
3356 
3357 
3358 // JNIid class for jfieldIDs only
3359 // Note to reviewers:
3360 // These JNI functions are just moved over to column 1 and not changed
3361 // in the compressed oops workspace.
3362 JNIid::JNIid(Klass* holder, int offset, JNIid* next) {
3363   _holder = holder;
3364   _offset = offset;
3365   _next = next;
3366   debug_only(_is_static_field_id = false;)
3367 }
3368 
3369 
3370 JNIid* JNIid::find(int offset) {
3371   JNIid* current = this;
3372   while (current != NULL) {
3373     if (current->offset() == offset) return current;
3374     current = current->next();
3375   }
3376   return NULL;
3377 }
3378 
3379 void JNIid::deallocate(JNIid* current) {
3380   while (current != NULL) {
3381     JNIid* next = current->next();
3382     delete current;
3383     current = next;
3384   }
3385 }
3386 
3387 
3388 void JNIid::verify(Klass* holder) {
3389   int first_field_offset  = InstanceMirrorKlass::offset_of_static_fields();
3390   int end_field_offset;
3391   end_field_offset = first_field_offset + (InstanceKlass::cast(holder)->static_field_size() * wordSize);
3392 
3393   JNIid* current = this;
3394   while (current != NULL) {
3395     guarantee(current->holder() == holder, "Invalid klass in JNIid");
3396 #ifdef ASSERT
3397     int o = current->offset();
3398     if (current->is_static_field_id()) {
3399       guarantee(o >= first_field_offset  && o < end_field_offset,  "Invalid static field offset in JNIid");
3400     }
3401 #endif
3402     current = current->next();
3403   }
3404 }
3405 
3406 
3407 #ifdef ASSERT
3408 void InstanceKlass::set_init_state(ClassState state) {
3409   bool good_state = is_shared() ? (_init_state <= state)
3410                                                : (_init_state < state);
3411   assert(good_state || state == allocated, "illegal state transition");
3412   _init_state = (u1)state;
3413 }
3414 #endif
3415 
3416 #if INCLUDE_JVMTI
3417 
3418 // RedefineClasses() support for previous versions
3419 
3420 // Globally, there is at least one previous version of a class to walk
3421 // during class unloading, which is saved because old methods in the class
3422 // are still running.   Otherwise the previous version list is cleaned up.
3423 bool InstanceKlass::_has_previous_versions = false;
3424 
3425 // Returns true if there are previous versions of a class for class
3426 // unloading only. Also resets the flag to false. purge_previous_version
3427 // will set the flag to true if there are any left, i.e., if there's any
3428 // work to do for next time. This is to avoid the expensive code cache
3429 // walk in CLDG::do_unloading().
3430 bool InstanceKlass::has_previous_versions_and_reset() {
3431   bool ret = _has_previous_versions;
3432   log_trace(redefine, class, iklass, purge)("Class unloading: has_previous_versions = %s",
3433      ret ? "true" : "false");
3434   _has_previous_versions = false;
3435   return ret;
3436 }
3437 
3438 // Purge previous versions before adding new previous versions of the class and
3439 // during class unloading.
3440 void InstanceKlass::purge_previous_version_list() {
3441   assert(SafepointSynchronize::is_at_safepoint(), "only called at safepoint");
3442   assert(has_been_redefined(), "Should only be called for main class");
3443 
3444   // Quick exit.
3445   if (previous_versions() == NULL) {
3446     return;
3447   }
3448 
3449   // This klass has previous versions so see what we can cleanup
3450   // while it is safe to do so.
3451 
3452   int deleted_count = 0;    // leave debugging breadcrumbs
3453   int live_count = 0;
3454   ClassLoaderData* loader_data = class_loader_data();
3455   assert(loader_data != NULL, "should never be null");
3456 
3457   ResourceMark rm;
3458   log_trace(redefine, class, iklass, purge)("%s: previous versions", external_name());
3459 
3460   // previous versions are linked together through the InstanceKlass
3461   InstanceKlass* pv_node = previous_versions();
3462   InstanceKlass* last = this;
3463   int version = 0;
3464 
3465   // check the previous versions list
3466   for (; pv_node != NULL; ) {
3467 
3468     ConstantPool* pvcp = pv_node->constants();
3469     assert(pvcp != NULL, "cp ref was unexpectedly cleared");
3470 
3471     if (!pvcp->on_stack()) {
3472       // If the constant pool isn't on stack, none of the methods
3473       // are executing.  Unlink this previous_version.
3474       // The previous version InstanceKlass is on the ClassLoaderData deallocate list
3475       // so will be deallocated during the next phase of class unloading.
3476       log_trace(redefine, class, iklass, purge)
3477         ("previous version " INTPTR_FORMAT " is dead.", p2i(pv_node));
3478       // For debugging purposes.
3479       pv_node->set_is_scratch_class();
3480       // Unlink from previous version list.
3481       assert(pv_node->class_loader_data() == loader_data, "wrong loader_data");
3482       InstanceKlass* next = pv_node->previous_versions();
3483       pv_node->link_previous_versions(NULL);   // point next to NULL
3484       last->link_previous_versions(next);
3485       // Add to the deallocate list after unlinking
3486       loader_data->add_to_deallocate_list(pv_node);
3487       pv_node = next;
3488       deleted_count++;
3489       version++;
3490       continue;
3491     } else {
3492       log_trace(redefine, class, iklass, purge)("previous version " INTPTR_FORMAT " is alive", p2i(pv_node));
3493       assert(pvcp->pool_holder() != NULL, "Constant pool with no holder");
3494       guarantee (!loader_data->is_unloading(), "unloaded classes can't be on the stack");
3495       live_count++;
3496       // found a previous version for next time we do class unloading
3497       _has_previous_versions = true;
3498     }
3499 
3500     // At least one method is live in this previous version.
3501     // Reset dead EMCP methods not to get breakpoints.
3502     // All methods are deallocated when all of the methods for this class are no
3503     // longer running.
3504     Array<Method*>* method_refs = pv_node->methods();
3505     if (method_refs != NULL) {
3506       log_trace(redefine, class, iklass, purge)("previous methods length=%d", method_refs->length());
3507       for (int j = 0; j < method_refs->length(); j++) {
3508         Method* method = method_refs->at(j);
3509 
3510         if (!method->on_stack()) {
3511           // no breakpoints for non-running methods
3512           if (method->is_running_emcp()) {
3513             method->set_running_emcp(false);
3514           }
3515         } else {
3516           assert (method->is_obsolete() || method->is_running_emcp(),
3517                   "emcp method cannot run after emcp bit is cleared");
3518           log_trace(redefine, class, iklass, purge)
3519             ("purge: %s(%s): prev method @%d in version @%d is alive",
3520              method->name()->as_C_string(), method->signature()->as_C_string(), j, version);
3521         }
3522       }
3523     }
3524     // next previous version
3525     last = pv_node;
3526     pv_node = pv_node->previous_versions();
3527     version++;
3528   }
3529   log_trace(redefine, class, iklass, purge)
3530     ("previous version stats: live=%d, deleted=%d", live_count, deleted_count);
3531 }
3532 
3533 void InstanceKlass::mark_newly_obsolete_methods(Array<Method*>* old_methods,
3534                                                 int emcp_method_count) {
3535   int obsolete_method_count = old_methods->length() - emcp_method_count;
3536 
3537   if (emcp_method_count != 0 && obsolete_method_count != 0 &&
3538       _previous_versions != NULL) {
3539     // We have a mix of obsolete and EMCP methods so we have to
3540     // clear out any matching EMCP method entries the hard way.
3541     int local_count = 0;
3542     for (int i = 0; i < old_methods->length(); i++) {
3543       Method* old_method = old_methods->at(i);
3544       if (old_method->is_obsolete()) {
3545         // only obsolete methods are interesting
3546         Symbol* m_name = old_method->name();
3547         Symbol* m_signature = old_method->signature();
3548 
3549         // previous versions are linked together through the InstanceKlass
3550         int j = 0;
3551         for (InstanceKlass* prev_version = _previous_versions;
3552              prev_version != NULL;
3553              prev_version = prev_version->previous_versions(), j++) {
3554 
3555           Array<Method*>* method_refs = prev_version->methods();
3556           for (int k = 0; k < method_refs->length(); k++) {
3557             Method* method = method_refs->at(k);
3558 
3559             if (!method->is_obsolete() &&
3560                 method->name() == m_name &&
3561                 method->signature() == m_signature) {
3562               // The current RedefineClasses() call has made all EMCP
3563               // versions of this method obsolete so mark it as obsolete
3564               log_trace(redefine, class, iklass, add)
3565                 ("%s(%s): flush obsolete method @%d in version @%d",
3566                  m_name->as_C_string(), m_signature->as_C_string(), k, j);
3567 
3568               method->set_is_obsolete();
3569               break;
3570             }
3571           }
3572 
3573           // The previous loop may not find a matching EMCP method, but
3574           // that doesn't mean that we can optimize and not go any
3575           // further back in the PreviousVersion generations. The EMCP
3576           // method for this generation could have already been made obsolete,
3577           // but there still may be an older EMCP method that has not
3578           // been made obsolete.
3579         }
3580 
3581         if (++local_count >= obsolete_method_count) {
3582           // no more obsolete methods so bail out now
3583           break;
3584         }
3585       }
3586     }
3587   }
3588 }
3589 
3590 // Save the scratch_class as the previous version if any of the methods are running.
3591 // The previous_versions are used to set breakpoints in EMCP methods and they are
3592 // also used to clean MethodData links to redefined methods that are no longer running.
3593 void InstanceKlass::add_previous_version(InstanceKlass* scratch_class,
3594                                          int emcp_method_count) {
3595   assert(Thread::current()->is_VM_thread(),
3596          "only VMThread can add previous versions");
3597 
3598   ResourceMark rm;
3599   log_trace(redefine, class, iklass, add)
3600     ("adding previous version ref for %s, EMCP_cnt=%d", scratch_class->external_name(), emcp_method_count);
3601 
3602   // Clean out old previous versions for this class
3603   purge_previous_version_list();
3604 
3605   // Mark newly obsolete methods in remaining previous versions.  An EMCP method from
3606   // a previous redefinition may be made obsolete by this redefinition.
3607   Array<Method*>* old_methods = scratch_class->methods();
3608   mark_newly_obsolete_methods(old_methods, emcp_method_count);
3609 
3610   // If the constant pool for this previous version of the class
3611   // is not marked as being on the stack, then none of the methods
3612   // in this previous version of the class are on the stack so
3613   // we don't need to add this as a previous version.
3614   ConstantPool* cp_ref = scratch_class->constants();
3615   if (!cp_ref->on_stack()) {
3616     log_trace(redefine, class, iklass, add)("scratch class not added; no methods are running");
3617     // For debugging purposes.
3618     scratch_class->set_is_scratch_class();
3619     scratch_class->class_loader_data()->add_to_deallocate_list(scratch_class);
3620     return;
3621   }
3622 
3623   if (emcp_method_count != 0) {
3624     // At least one method is still running, check for EMCP methods
3625     for (int i = 0; i < old_methods->length(); i++) {
3626       Method* old_method = old_methods->at(i);
3627       if (!old_method->is_obsolete() && old_method->on_stack()) {
3628         // if EMCP method (not obsolete) is on the stack, mark as EMCP so that
3629         // we can add breakpoints for it.
3630 
3631         // We set the method->on_stack bit during safepoints for class redefinition
3632         // and use this bit to set the is_running_emcp bit.
3633         // After the safepoint, the on_stack bit is cleared and the running emcp
3634         // method may exit.   If so, we would set a breakpoint in a method that
3635         // is never reached, but this won't be noticeable to the programmer.
3636         old_method->set_running_emcp(true);
3637         log_trace(redefine, class, iklass, add)
3638           ("EMCP method %s is on_stack " INTPTR_FORMAT, old_method->name_and_sig_as_C_string(), p2i(old_method));
3639       } else if (!old_method->is_obsolete()) {
3640         log_trace(redefine, class, iklass, add)
3641           ("EMCP method %s is NOT on_stack " INTPTR_FORMAT, old_method->name_and_sig_as_C_string(), p2i(old_method));
3642       }
3643     }
3644   }
3645 
3646   // Add previous version if any methods are still running.
3647   // Set has_previous_version flag for processing during class unloading.
3648   _has_previous_versions = true;
3649   log_trace(redefine, class, iklass, add) ("scratch class added; one of its methods is on_stack.");
3650   assert(scratch_class->previous_versions() == NULL, "shouldn't have a previous version");
3651   scratch_class->link_previous_versions(previous_versions());
3652   link_previous_versions(scratch_class);
3653 } // end add_previous_version()
3654 
3655 #endif // INCLUDE_JVMTI
3656 
3657 Method* InstanceKlass::method_with_idnum(int idnum) {
3658   Method* m = NULL;
3659   if (idnum < methods()->length()) {
3660     m = methods()->at(idnum);
3661   }
3662   if (m == NULL || m->method_idnum() != idnum) {
3663     for (int index = 0; index < methods()->length(); ++index) {
3664       m = methods()->at(index);
3665       if (m->method_idnum() == idnum) {
3666         return m;
3667       }
3668     }
3669     // None found, return null for the caller to handle.
3670     return NULL;
3671   }
3672   return m;
3673 }
3674 
3675 
3676 Method* InstanceKlass::method_with_orig_idnum(int idnum) {
3677   if (idnum >= methods()->length()) {
3678     return NULL;
3679   }
3680   Method* m = methods()->at(idnum);
3681   if (m != NULL && m->orig_method_idnum() == idnum) {
3682     return m;
3683   }
3684   // Obsolete method idnum does not match the original idnum
3685   for (int index = 0; index < methods()->length(); ++index) {
3686     m = methods()->at(index);
3687     if (m->orig_method_idnum() == idnum) {
3688       return m;
3689     }
3690   }
3691   // None found, return null for the caller to handle.
3692   return NULL;
3693 }
3694 
3695 
3696 Method* InstanceKlass::method_with_orig_idnum(int idnum, int version) {
3697   InstanceKlass* holder = get_klass_version(version);
3698   if (holder == NULL) {
3699     return NULL; // The version of klass is gone, no method is found
3700   }
3701   Method* method = holder->method_with_orig_idnum(idnum);
3702   return method;
3703 }
3704 
3705 #if INCLUDE_JVMTI
3706 JvmtiCachedClassFileData* InstanceKlass::get_cached_class_file() {
3707   if (MetaspaceShared::is_in_shared_space(_cached_class_file)) {
3708     // Ignore the archived class stream data
3709     return NULL;
3710   } else {
3711     return _cached_class_file;
3712   }
3713 }
3714 
3715 jint InstanceKlass::get_cached_class_file_len() {
3716   return VM_RedefineClasses::get_cached_class_file_len(_cached_class_file);
3717 }
3718 
3719 unsigned char * InstanceKlass::get_cached_class_file_bytes() {
3720   return VM_RedefineClasses::get_cached_class_file_bytes(_cached_class_file);
3721 }
3722 
3723 #if INCLUDE_CDS
3724 JvmtiCachedClassFileData* InstanceKlass::get_archived_class_data() {
3725   if (DumpSharedSpaces) {
3726     return _cached_class_file;
3727   } else {
3728     assert(this->is_shared(), "class should be shared");
3729     if (MetaspaceShared::is_in_shared_space(_cached_class_file)) {
3730       return _cached_class_file;
3731     } else {
3732       return NULL;
3733     }
3734   }
3735 }
3736 #endif
3737 #endif