1 /*
   2  * Copyright (c) 1997, 2011, 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 "classfile/javaClasses.hpp"
  27 #include "classfile/systemDictionary.hpp"
  28 #include "classfile/verifier.hpp"
  29 #include "classfile/vmSymbols.hpp"
  30 #include "compiler/compileBroker.hpp"
  31 #include "gc_implementation/shared/markSweep.inline.hpp"
  32 #include "gc_interface/collectedHeap.inline.hpp"
  33 #include "interpreter/oopMapCache.hpp"
  34 #include "interpreter/rewriter.hpp"
  35 #include "jvmtifiles/jvmti.h"
  36 #include "memory/genOopClosures.inline.hpp"
  37 #include "memory/oopFactory.hpp"
  38 #include "memory/permGen.hpp"
  39 #include "oops/fieldStreams.hpp"
  40 #include "oops/instanceKlass.hpp"
  41 #include "oops/instanceMirrorKlass.hpp"
  42 #include "oops/instanceOop.hpp"
  43 #include "oops/methodOop.hpp"
  44 #include "oops/objArrayKlassKlass.hpp"
  45 #include "oops/oop.inline.hpp"
  46 #include "oops/symbol.hpp"
  47 #include "prims/jvmtiExport.hpp"
  48 #include "prims/jvmtiRedefineClassesTrace.hpp"
  49 #include "runtime/fieldDescriptor.hpp"
  50 #include "runtime/handles.inline.hpp"
  51 #include "runtime/javaCalls.hpp"
  52 #include "runtime/mutexLocker.hpp"
  53 #include "services/threadService.hpp"
  54 #include "utilities/dtrace.hpp"
  55 #ifdef TARGET_OS_FAMILY_linux
  56 # include "thread_linux.inline.hpp"
  57 #endif
  58 #ifdef TARGET_OS_FAMILY_solaris
  59 # include "thread_solaris.inline.hpp"
  60 #endif
  61 #ifdef TARGET_OS_FAMILY_windows
  62 # include "thread_windows.inline.hpp"
  63 #endif
  64 #ifdef TARGET_OS_FAMILY_bsd
  65 # include "thread_bsd.inline.hpp"
  66 #endif
  67 #ifndef SERIALGC
  68 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
  69 #include "gc_implementation/g1/g1OopClosures.inline.hpp"
  70 #include "gc_implementation/g1/g1RemSet.inline.hpp"
  71 #include "gc_implementation/g1/heapRegionSeq.inline.hpp"
  72 #include "gc_implementation/parNew/parOopClosures.inline.hpp"
  73 #include "gc_implementation/parallelScavenge/psPromotionManager.inline.hpp"
  74 #include "gc_implementation/parallelScavenge/psScavenge.inline.hpp"
  75 #include "oops/oop.pcgc.inline.hpp"
  76 #endif
  77 #ifdef COMPILER1
  78 #include "c1/c1_Compiler.hpp"
  79 #endif
  80 
  81 #ifdef DTRACE_ENABLED
  82 
  83 #ifndef USDT2
  84 
  85 HS_DTRACE_PROBE_DECL4(hotspot, class__initialization__required,
  86   char*, intptr_t, oop, intptr_t);
  87 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__recursive,
  88   char*, intptr_t, oop, intptr_t, int);
  89 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__concurrent,
  90   char*, intptr_t, oop, intptr_t, int);
  91 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__erroneous,
  92   char*, intptr_t, oop, intptr_t, int);
  93 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__super__failed,
  94   char*, intptr_t, oop, intptr_t, int);
  95 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__clinit,
  96   char*, intptr_t, oop, intptr_t, int);
  97 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__error,
  98   char*, intptr_t, oop, intptr_t, int);
  99 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__end,
 100   char*, intptr_t, oop, intptr_t, int);
 101 
 102 #define DTRACE_CLASSINIT_PROBE(type, clss, thread_type)          \
 103   {                                                              \
 104     char* data = NULL;                                           \
 105     int len = 0;                                                 \
 106     Symbol* name = (clss)->name();                               \
 107     if (name != NULL) {                                          \
 108       data = (char*)name->bytes();                               \
 109       len = name->utf8_length();                                 \
 110     }                                                            \
 111     HS_DTRACE_PROBE4(hotspot, class__initialization__##type,     \
 112       data, len, (clss)->class_loader(), thread_type);           \
 113   }
 114 
 115 #define DTRACE_CLASSINIT_PROBE_WAIT(type, clss, thread_type, wait) \
 116   {                                                              \
 117     char* data = NULL;                                           \
 118     int len = 0;                                                 \
 119     Symbol* name = (clss)->name();                               \
 120     if (name != NULL) {                                          \
 121       data = (char*)name->bytes();                               \
 122       len = name->utf8_length();                                 \
 123     }                                                            \
 124     HS_DTRACE_PROBE5(hotspot, class__initialization__##type,     \
 125       data, len, (clss)->class_loader(), thread_type, wait);     \
 126   }
 127 #else /* USDT2 */
 128 
 129 #define HOTSPOT_CLASS_INITIALIZATION_required HOTSPOT_CLASS_INITIALIZATION_REQUIRED
 130 #define HOTSPOT_CLASS_INITIALIZATION_recursive HOTSPOT_CLASS_INITIALIZATION_RECURSIVE
 131 #define HOTSPOT_CLASS_INITIALIZATION_concurrent HOTSPOT_CLASS_INITIALIZATION_CONCURRENT
 132 #define HOTSPOT_CLASS_INITIALIZATION_erroneous HOTSPOT_CLASS_INITIALIZATION_ERRONEOUS
 133 #define HOTSPOT_CLASS_INITIALIZATION_super__failed HOTSPOT_CLASS_INITIALIZATION_SUPER_FAILED
 134 #define HOTSPOT_CLASS_INITIALIZATION_clinit HOTSPOT_CLASS_INITIALIZATION_CLINIT
 135 #define HOTSPOT_CLASS_INITIALIZATION_error HOTSPOT_CLASS_INITIALIZATION_ERROR
 136 #define HOTSPOT_CLASS_INITIALIZATION_end HOTSPOT_CLASS_INITIALIZATION_END
 137 #define DTRACE_CLASSINIT_PROBE(type, clss, thread_type)          \
 138   {                                                              \
 139     char* data = NULL;                                           \
 140     int len = 0;                                                 \
 141     Symbol* name = (clss)->name();                               \
 142     if (name != NULL) {                                          \
 143       data = (char*)name->bytes();                               \
 144       len = name->utf8_length();                                 \
 145     }                                                            \
 146     HOTSPOT_CLASS_INITIALIZATION_##type(                         \
 147       data, len, (clss)->class_loader(), thread_type);           \
 148   }
 149 
 150 #define DTRACE_CLASSINIT_PROBE_WAIT(type, clss, thread_type, wait) \
 151   {                                                              \
 152     char* data = NULL;                                           \
 153     int len = 0;                                                 \
 154     Symbol* name = (clss)->name();                               \
 155     if (name != NULL) {                                          \
 156       data = (char*)name->bytes();                               \
 157       len = name->utf8_length();                                 \
 158     }                                                            \
 159     HOTSPOT_CLASS_INITIALIZATION_##type(                         \
 160       data, len, (clss)->class_loader(), thread_type, wait);     \
 161   }
 162 #endif /* USDT2 */
 163 
 164 #else //  ndef DTRACE_ENABLED
 165 
 166 #define DTRACE_CLASSINIT_PROBE(type, clss, thread_type)
 167 #define DTRACE_CLASSINIT_PROBE_WAIT(type, clss, thread_type, wait)
 168 
 169 #endif //  ndef DTRACE_ENABLED
 170 
 171 bool instanceKlass::should_be_initialized() const {
 172   return !is_initialized();
 173 }
 174 
 175 klassVtable* instanceKlass::vtable() const {
 176   return new klassVtable(as_klassOop(), start_of_vtable(), vtable_length() / vtableEntry::size());
 177 }
 178 
 179 klassItable* instanceKlass::itable() const {
 180   return new klassItable(as_klassOop());
 181 }
 182 
 183 void instanceKlass::eager_initialize(Thread *thread) {
 184   if (!EagerInitialization) return;
 185 
 186   if (this->is_not_initialized()) {
 187     // abort if the the class has a class initializer
 188     if (this->class_initializer() != NULL) return;
 189 
 190     // abort if it is java.lang.Object (initialization is handled in genesis)
 191     klassOop super = this->super();
 192     if (super == NULL) return;
 193 
 194     // abort if the super class should be initialized
 195     if (!instanceKlass::cast(super)->is_initialized()) return;
 196 
 197     // call body to expose the this pointer
 198     instanceKlassHandle this_oop(thread, this->as_klassOop());
 199     eager_initialize_impl(this_oop);
 200   }
 201 }
 202 
 203 
 204 void instanceKlass::eager_initialize_impl(instanceKlassHandle this_oop) {
 205   EXCEPTION_MARK;
 206   ObjectLocker ol(this_oop, THREAD);
 207 
 208   // abort if someone beat us to the initialization
 209   if (!this_oop->is_not_initialized()) return;  // note: not equivalent to is_initialized()
 210 
 211   ClassState old_state = this_oop->init_state();
 212   link_class_impl(this_oop, true, THREAD);
 213   if (HAS_PENDING_EXCEPTION) {
 214     CLEAR_PENDING_EXCEPTION;
 215     // Abort if linking the class throws an exception.
 216 
 217     // Use a test to avoid redundantly resetting the state if there's
 218     // no change.  Set_init_state() asserts that state changes make
 219     // progress, whereas here we might just be spinning in place.
 220     if( old_state != this_oop->_init_state )
 221       this_oop->set_init_state (old_state);
 222   } else {
 223     // linking successfull, mark class as initialized
 224     this_oop->set_init_state (fully_initialized);
 225     // trace
 226     if (TraceClassInitialization) {
 227       ResourceMark rm(THREAD);
 228       tty->print_cr("[Initialized %s without side effects]", this_oop->external_name());
 229     }
 230   }
 231 }
 232 
 233 
 234 // See "The Virtual Machine Specification" section 2.16.5 for a detailed explanation of the class initialization
 235 // process. The step comments refers to the procedure described in that section.
 236 // Note: implementation moved to static method to expose the this pointer.
 237 void instanceKlass::initialize(TRAPS) {
 238   if (this->should_be_initialized()) {
 239     HandleMark hm(THREAD);
 240     instanceKlassHandle this_oop(THREAD, this->as_klassOop());
 241     initialize_impl(this_oop, CHECK);
 242     // Note: at this point the class may be initialized
 243     //       OR it may be in the state of being initialized
 244     //       in case of recursive initialization!
 245   } else {
 246     assert(is_initialized(), "sanity check");
 247   }
 248 }
 249 
 250 
 251 bool instanceKlass::verify_code(
 252     instanceKlassHandle this_oop, bool throw_verifyerror, TRAPS) {
 253   // 1) Verify the bytecodes
 254   Verifier::Mode mode =
 255     throw_verifyerror ? Verifier::ThrowException : Verifier::NoException;
 256   return Verifier::verify(this_oop, mode, this_oop->should_verify_class(), CHECK_false);
 257 }
 258 
 259 
 260 // Used exclusively by the shared spaces dump mechanism to prevent
 261 // classes mapped into the shared regions in new VMs from appearing linked.
 262 
 263 void instanceKlass::unlink_class() {
 264   assert(is_linked(), "must be linked");
 265   _init_state = loaded;
 266 }
 267 
 268 void instanceKlass::link_class(TRAPS) {
 269   assert(is_loaded(), "must be loaded");
 270   if (!is_linked()) {
 271     instanceKlassHandle this_oop(THREAD, this->as_klassOop());
 272     link_class_impl(this_oop, true, CHECK);
 273   }
 274 }
 275 
 276 // Called to verify that a class can link during initialization, without
 277 // throwing a VerifyError.
 278 bool instanceKlass::link_class_or_fail(TRAPS) {
 279   assert(is_loaded(), "must be loaded");
 280   if (!is_linked()) {
 281     instanceKlassHandle this_oop(THREAD, this->as_klassOop());
 282     link_class_impl(this_oop, false, CHECK_false);
 283   }
 284   return is_linked();
 285 }
 286 
 287 bool instanceKlass::link_class_impl(
 288     instanceKlassHandle this_oop, bool throw_verifyerror, TRAPS) {
 289   // check for error state
 290   if (this_oop->is_in_error_state()) {
 291     ResourceMark rm(THREAD);
 292     THROW_MSG_(vmSymbols::java_lang_NoClassDefFoundError(),
 293                this_oop->external_name(), false);
 294   }
 295   // return if already verified
 296   if (this_oop->is_linked()) {
 297     return true;
 298   }
 299 
 300   // Timing
 301   // timer handles recursion
 302   assert(THREAD->is_Java_thread(), "non-JavaThread in link_class_impl");
 303   JavaThread* jt = (JavaThread*)THREAD;
 304 
 305   // link super class before linking this class
 306   instanceKlassHandle super(THREAD, this_oop->super());
 307   if (super.not_null()) {
 308     if (super->is_interface()) {  // check if super class is an interface
 309       ResourceMark rm(THREAD);
 310       Exceptions::fthrow(
 311         THREAD_AND_LOCATION,
 312         vmSymbols::java_lang_IncompatibleClassChangeError(),
 313         "class %s has interface %s as super class",
 314         this_oop->external_name(),
 315         super->external_name()
 316       );
 317       return false;
 318     }
 319 
 320     link_class_impl(super, throw_verifyerror, CHECK_false);
 321   }
 322 
 323   // link all interfaces implemented by this class before linking this class
 324   objArrayHandle interfaces (THREAD, this_oop->local_interfaces());
 325   int num_interfaces = interfaces->length();
 326   for (int index = 0; index < num_interfaces; index++) {
 327     HandleMark hm(THREAD);
 328     instanceKlassHandle ih(THREAD, klassOop(interfaces->obj_at(index)));
 329     link_class_impl(ih, throw_verifyerror, CHECK_false);
 330   }
 331 
 332   // in case the class is linked in the process of linking its superclasses
 333   if (this_oop->is_linked()) {
 334     return true;
 335   }
 336 
 337   // trace only the link time for this klass that includes
 338   // the verification time
 339   PerfClassTraceTime vmtimer(ClassLoader::perf_class_link_time(),
 340                              ClassLoader::perf_class_link_selftime(),
 341                              ClassLoader::perf_classes_linked(),
 342                              jt->get_thread_stat()->perf_recursion_counts_addr(),
 343                              jt->get_thread_stat()->perf_timers_addr(),
 344                              PerfClassTraceTime::CLASS_LINK);
 345 
 346   // verification & rewriting
 347   {
 348     ObjectLocker ol(this_oop, THREAD);
 349     // rewritten will have been set if loader constraint error found
 350     // on an earlier link attempt
 351     // don't verify or rewrite if already rewritten
 352     if (!this_oop->is_linked()) {
 353       if (!this_oop->is_rewritten()) {
 354         {
 355           // Timer includes any side effects of class verification (resolution,
 356           // etc), but not recursive entry into verify_code().
 357           PerfClassTraceTime timer(ClassLoader::perf_class_verify_time(),
 358                                    ClassLoader::perf_class_verify_selftime(),
 359                                    ClassLoader::perf_classes_verified(),
 360                                    jt->get_thread_stat()->perf_recursion_counts_addr(),
 361                                    jt->get_thread_stat()->perf_timers_addr(),
 362                                    PerfClassTraceTime::CLASS_VERIFY);
 363           bool verify_ok = verify_code(this_oop, throw_verifyerror, THREAD);
 364           if (!verify_ok) {
 365             return false;
 366           }
 367         }
 368 
 369         // Just in case a side-effect of verify linked this class already
 370         // (which can sometimes happen since the verifier loads classes
 371         // using custom class loaders, which are free to initialize things)
 372         if (this_oop->is_linked()) {
 373           return true;
 374         }
 375 
 376         // also sets rewritten
 377         this_oop->rewrite_class(CHECK_false);
 378       }
 379 
 380       // relocate jsrs and link methods after they are all rewritten
 381       this_oop->relocate_and_link_methods(CHECK_false);
 382 
 383       // Initialize the vtable and interface table after
 384       // methods have been rewritten since rewrite may
 385       // fabricate new methodOops.
 386       // also does loader constraint checking
 387       if (!this_oop()->is_shared()) {
 388         ResourceMark rm(THREAD);
 389         this_oop->vtable()->initialize_vtable(true, CHECK_false);
 390         this_oop->itable()->initialize_itable(true, CHECK_false);
 391       }
 392 #ifdef ASSERT
 393       else {
 394         ResourceMark rm(THREAD);
 395         this_oop->vtable()->verify(tty, true);
 396         // In case itable verification is ever added.
 397         // this_oop->itable()->verify(tty, true);
 398       }
 399 #endif
 400       this_oop->set_init_state(linked);
 401       if (JvmtiExport::should_post_class_prepare()) {
 402         Thread *thread = THREAD;
 403         assert(thread->is_Java_thread(), "thread->is_Java_thread()");
 404         JvmtiExport::post_class_prepare((JavaThread *) thread, this_oop());
 405       }
 406     }
 407   }
 408   return true;
 409 }
 410 
 411 
 412 // Rewrite the byte codes of all of the methods of a class.
 413 // The rewriter must be called exactly once. Rewriting must happen after
 414 // verification but before the first method of the class is executed.
 415 void instanceKlass::rewrite_class(TRAPS) {
 416   assert(is_loaded(), "must be loaded");
 417   instanceKlassHandle this_oop(THREAD, this->as_klassOop());
 418   if (this_oop->is_rewritten()) {
 419     assert(this_oop()->is_shared(), "rewriting an unshared class?");
 420     return;
 421   }
 422   Rewriter::rewrite(this_oop, CHECK);
 423   this_oop->set_rewritten();
 424 }
 425 
 426 // Now relocate and link method entry points after class is rewritten.
 427 // This is outside is_rewritten flag. In case of an exception, it can be
 428 // executed more than once.
 429 void instanceKlass::relocate_and_link_methods(TRAPS) {
 430   assert(is_loaded(), "must be loaded");
 431   instanceKlassHandle this_oop(THREAD, this->as_klassOop());
 432   Rewriter::relocate_and_link(this_oop, CHECK);
 433 }
 434 
 435 
 436 void instanceKlass::initialize_impl(instanceKlassHandle this_oop, TRAPS) {
 437   // Make sure klass is linked (verified) before initialization
 438   // A class could already be verified, since it has been reflected upon.
 439   this_oop->link_class(CHECK);
 440 
 441   DTRACE_CLASSINIT_PROBE(required, instanceKlass::cast(this_oop()), -1);
 442 
 443   bool wait = false;
 444 
 445   // refer to the JVM book page 47 for description of steps
 446   // Step 1
 447   { ObjectLocker ol(this_oop, THREAD);
 448 
 449     Thread *self = THREAD; // it's passed the current thread
 450 
 451     // Step 2
 452     // If we were to use wait() instead of waitInterruptibly() then
 453     // we might end up throwing IE from link/symbol resolution sites
 454     // that aren't expected to throw.  This would wreak havoc.  See 6320309.
 455     while(this_oop->is_being_initialized() && !this_oop->is_reentrant_initialization(self)) {
 456         wait = true;
 457       ol.waitUninterruptibly(CHECK);
 458     }
 459 
 460     // Step 3
 461     if (this_oop->is_being_initialized() && this_oop->is_reentrant_initialization(self)) {
 462       DTRACE_CLASSINIT_PROBE_WAIT(recursive, instanceKlass::cast(this_oop()), -1,wait);
 463       return;
 464     }
 465 
 466     // Step 4
 467     if (this_oop->is_initialized()) {
 468       DTRACE_CLASSINIT_PROBE_WAIT(concurrent, instanceKlass::cast(this_oop()), -1,wait);
 469       return;
 470     }
 471 
 472     // Step 5
 473     if (this_oop->is_in_error_state()) {
 474       DTRACE_CLASSINIT_PROBE_WAIT(erroneous, instanceKlass::cast(this_oop()), -1,wait);
 475       ResourceMark rm(THREAD);
 476       const char* desc = "Could not initialize class ";
 477       const char* className = this_oop->external_name();
 478       size_t msglen = strlen(desc) + strlen(className) + 1;
 479       char* message = NEW_RESOURCE_ARRAY(char, msglen);
 480       if (NULL == message) {
 481         // Out of memory: can't create detailed error message
 482         THROW_MSG(vmSymbols::java_lang_NoClassDefFoundError(), className);
 483       } else {
 484         jio_snprintf(message, msglen, "%s%s", desc, className);
 485         THROW_MSG(vmSymbols::java_lang_NoClassDefFoundError(), message);
 486       }
 487     }
 488 
 489     // Step 6
 490     this_oop->set_init_state(being_initialized);
 491     this_oop->set_init_thread(self);
 492   }
 493 
 494   // Step 7
 495   klassOop super_klass = this_oop->super();
 496   if (super_klass != NULL && !this_oop->is_interface() && Klass::cast(super_klass)->should_be_initialized()) {
 497     Klass::cast(super_klass)->initialize(THREAD);
 498 
 499     if (HAS_PENDING_EXCEPTION) {
 500       Handle e(THREAD, PENDING_EXCEPTION);
 501       CLEAR_PENDING_EXCEPTION;
 502       {
 503         EXCEPTION_MARK;
 504         this_oop->set_initialization_state_and_notify(initialization_error, THREAD); // Locks object, set state, and notify all waiting threads
 505         CLEAR_PENDING_EXCEPTION;   // ignore any exception thrown, superclass initialization error is thrown below
 506       }
 507       DTRACE_CLASSINIT_PROBE_WAIT(super__failed, instanceKlass::cast(this_oop()), -1,wait);
 508       THROW_OOP(e());
 509     }
 510   }
 511 
 512   // Step 8
 513   {
 514     assert(THREAD->is_Java_thread(), "non-JavaThread in initialize_impl");
 515     JavaThread* jt = (JavaThread*)THREAD;
 516     DTRACE_CLASSINIT_PROBE_WAIT(clinit, instanceKlass::cast(this_oop()), -1,wait);
 517     // Timer includes any side effects of class initialization (resolution,
 518     // etc), but not recursive entry into call_class_initializer().
 519     PerfClassTraceTime timer(ClassLoader::perf_class_init_time(),
 520                              ClassLoader::perf_class_init_selftime(),
 521                              ClassLoader::perf_classes_inited(),
 522                              jt->get_thread_stat()->perf_recursion_counts_addr(),
 523                              jt->get_thread_stat()->perf_timers_addr(),
 524                              PerfClassTraceTime::CLASS_CLINIT);
 525     this_oop->call_class_initializer(THREAD);
 526   }
 527 
 528   // Step 9
 529   if (!HAS_PENDING_EXCEPTION) {
 530     this_oop->set_initialization_state_and_notify(fully_initialized, CHECK);
 531     { ResourceMark rm(THREAD);
 532       debug_only(this_oop->vtable()->verify(tty, true);)
 533     }
 534   }
 535   else {
 536     // Step 10 and 11
 537     Handle e(THREAD, PENDING_EXCEPTION);
 538     CLEAR_PENDING_EXCEPTION;
 539     {
 540       EXCEPTION_MARK;
 541       this_oop->set_initialization_state_and_notify(initialization_error, THREAD);
 542       CLEAR_PENDING_EXCEPTION;   // ignore any exception thrown, class initialization error is thrown below
 543     }
 544     DTRACE_CLASSINIT_PROBE_WAIT(error, instanceKlass::cast(this_oop()), -1,wait);
 545     if (e->is_a(SystemDictionary::Error_klass())) {
 546       THROW_OOP(e());
 547     } else {
 548       JavaCallArguments args(e);
 549       THROW_ARG(vmSymbols::java_lang_ExceptionInInitializerError(),
 550                 vmSymbols::throwable_void_signature(),
 551                 &args);
 552     }
 553   }
 554   DTRACE_CLASSINIT_PROBE_WAIT(end, instanceKlass::cast(this_oop()), -1,wait);
 555 }
 556 
 557 
 558 // Note: implementation moved to static method to expose the this pointer.
 559 void instanceKlass::set_initialization_state_and_notify(ClassState state, TRAPS) {
 560   instanceKlassHandle kh(THREAD, this->as_klassOop());
 561   set_initialization_state_and_notify_impl(kh, state, CHECK);
 562 }
 563 
 564 void instanceKlass::set_initialization_state_and_notify_impl(instanceKlassHandle this_oop, ClassState state, TRAPS) {
 565   ObjectLocker ol(this_oop, THREAD);
 566   this_oop->set_init_state(state);
 567   ol.notify_all(CHECK);
 568 }
 569 
 570 void instanceKlass::add_implementor(klassOop k) {
 571   assert(Compile_lock->owned_by_self(), "");
 572   // Filter out my subinterfaces.
 573   // (Note: Interfaces are never on the subklass list.)
 574   if (instanceKlass::cast(k)->is_interface()) return;
 575 
 576   // Filter out subclasses whose supers already implement me.
 577   // (Note: CHA must walk subclasses of direct implementors
 578   // in order to locate indirect implementors.)
 579   klassOop sk = instanceKlass::cast(k)->super();
 580   if (sk != NULL && instanceKlass::cast(sk)->implements_interface(as_klassOop()))
 581     // We only need to check one immediate superclass, since the
 582     // implements_interface query looks at transitive_interfaces.
 583     // Any supers of the super have the same (or fewer) transitive_interfaces.
 584     return;
 585 
 586   // Update number of implementors
 587   int i = _nof_implementors++;
 588 
 589   // Record this implementor, if there are not too many already
 590   if (i < implementors_limit) {
 591     assert(_implementors[i] == NULL, "should be exactly one implementor");
 592     oop_store_without_check((oop*)&_implementors[i], k);
 593   } else if (i == implementors_limit) {
 594     // clear out the list on first overflow
 595     for (int i2 = 0; i2 < implementors_limit; i2++)
 596       oop_store_without_check((oop*)&_implementors[i2], NULL);
 597   }
 598 
 599   // The implementor also implements the transitive_interfaces
 600   for (int index = 0; index < local_interfaces()->length(); index++) {
 601     instanceKlass::cast(klassOop(local_interfaces()->obj_at(index)))->add_implementor(k);
 602   }
 603 }
 604 
 605 void instanceKlass::init_implementor() {
 606   for (int i = 0; i < implementors_limit; i++)
 607     oop_store_without_check((oop*)&_implementors[i], NULL);
 608   _nof_implementors = 0;
 609 }
 610 
 611 
 612 void instanceKlass::process_interfaces(Thread *thread) {
 613   // link this class into the implementors list of every interface it implements
 614   KlassHandle this_as_oop (thread, this->as_klassOop());
 615   for (int i = local_interfaces()->length() - 1; i >= 0; i--) {
 616     assert(local_interfaces()->obj_at(i)->is_klass(), "must be a klass");
 617     instanceKlass* interf = instanceKlass::cast(klassOop(local_interfaces()->obj_at(i)));
 618     assert(interf->is_interface(), "expected interface");
 619     interf->add_implementor(this_as_oop());
 620   }
 621 }
 622 
 623 bool instanceKlass::can_be_primary_super_slow() const {
 624   if (is_interface())
 625     return false;
 626   else
 627     return Klass::can_be_primary_super_slow();
 628 }
 629 
 630 objArrayOop instanceKlass::compute_secondary_supers(int num_extra_slots, TRAPS) {
 631   // The secondaries are the implemented interfaces.
 632   instanceKlass* ik = instanceKlass::cast(as_klassOop());
 633   objArrayHandle interfaces (THREAD, ik->transitive_interfaces());
 634   int num_secondaries = num_extra_slots + interfaces->length();
 635   if (num_secondaries == 0) {
 636     return Universe::the_empty_system_obj_array();
 637   } else if (num_extra_slots == 0) {
 638     return interfaces();
 639   } else {
 640     // a mix of both
 641     objArrayOop secondaries = oopFactory::new_system_objArray(num_secondaries, CHECK_NULL);
 642     for (int i = 0; i < interfaces->length(); i++) {
 643       secondaries->obj_at_put(num_extra_slots+i, interfaces->obj_at(i));
 644     }
 645     return secondaries;
 646   }
 647 }
 648 
 649 bool instanceKlass::compute_is_subtype_of(klassOop k) {
 650   if (Klass::cast(k)->is_interface()) {
 651     return implements_interface(k);
 652   } else {
 653     return Klass::compute_is_subtype_of(k);
 654   }
 655 }
 656 
 657 bool instanceKlass::implements_interface(klassOop k) const {
 658   if (as_klassOop() == k) return true;
 659   assert(Klass::cast(k)->is_interface(), "should be an interface class");
 660   for (int i = 0; i < transitive_interfaces()->length(); i++) {
 661     if (transitive_interfaces()->obj_at(i) == k) {
 662       return true;
 663     }
 664   }
 665   return false;
 666 }
 667 
 668 objArrayOop instanceKlass::allocate_objArray(int n, int length, TRAPS) {
 669   if (length < 0) THROW_0(vmSymbols::java_lang_NegativeArraySizeException());
 670   if (length > arrayOopDesc::max_array_length(T_OBJECT)) {
 671     report_java_out_of_memory("Requested array size exceeds VM limit");
 672     THROW_OOP_0(Universe::out_of_memory_error_array_size());
 673   }
 674   int size = objArrayOopDesc::object_size(length);
 675   klassOop ak = array_klass(n, CHECK_NULL);
 676   KlassHandle h_ak (THREAD, ak);
 677   objArrayOop o =
 678     (objArrayOop)CollectedHeap::array_allocate(h_ak, size, length, CHECK_NULL);
 679   return o;
 680 }
 681 
 682 instanceOop instanceKlass::register_finalizer(instanceOop i, TRAPS) {
 683   if (TraceFinalizerRegistration) {
 684     tty->print("Registered ");
 685     i->print_value_on(tty);
 686     tty->print_cr(" (" INTPTR_FORMAT ") as finalizable", (address)i);
 687   }
 688   instanceHandle h_i(THREAD, i);
 689   // Pass the handle as argument, JavaCalls::call expects oop as jobjects
 690   JavaValue result(T_VOID);
 691   JavaCallArguments args(h_i);
 692   methodHandle mh (THREAD, Universe::finalizer_register_method());
 693   JavaCalls::call(&result, mh, &args, CHECK_NULL);
 694   return h_i();
 695 }
 696 
 697 instanceOop instanceKlass::allocate_instance(TRAPS) {
 698   assert(!oop_is_instanceMirror(), "wrong allocation path");
 699   bool has_finalizer_flag = has_finalizer(); // Query before possible GC
 700   int size = size_helper();  // Query before forming handle.
 701 
 702   KlassHandle h_k(THREAD, as_klassOop());
 703 
 704   instanceOop i;
 705 
 706   i = (instanceOop)CollectedHeap::obj_allocate(h_k, size, CHECK_NULL);
 707   if (has_finalizer_flag && !RegisterFinalizersAtInit) {
 708     i = register_finalizer(i, CHECK_NULL);
 709   }
 710   return i;
 711 }
 712 
 713 instanceOop instanceKlass::allocate_permanent_instance(TRAPS) {
 714   // Finalizer registration occurs in the Object.<init> constructor
 715   // and constructors normally aren't run when allocating perm
 716   // instances so simply disallow finalizable perm objects.  This can
 717   // be relaxed if a need for it is found.
 718   assert(!has_finalizer(), "perm objects not allowed to have finalizers");
 719   assert(!oop_is_instanceMirror(), "wrong allocation path");
 720   int size = size_helper();  // Query before forming handle.
 721   KlassHandle h_k(THREAD, as_klassOop());
 722   instanceOop i = (instanceOop)
 723     CollectedHeap::permanent_obj_allocate(h_k, size, CHECK_NULL);
 724   return i;
 725 }
 726 
 727 void instanceKlass::check_valid_for_instantiation(bool throwError, TRAPS) {
 728   if (is_interface() || is_abstract()) {
 729     ResourceMark rm(THREAD);
 730     THROW_MSG(throwError ? vmSymbols::java_lang_InstantiationError()
 731               : vmSymbols::java_lang_InstantiationException(), external_name());
 732   }
 733   if (as_klassOop() == SystemDictionary::Class_klass()) {
 734     ResourceMark rm(THREAD);
 735     THROW_MSG(throwError ? vmSymbols::java_lang_IllegalAccessError()
 736               : vmSymbols::java_lang_IllegalAccessException(), external_name());
 737   }
 738 }
 739 
 740 klassOop instanceKlass::array_klass_impl(bool or_null, int n, TRAPS) {
 741   instanceKlassHandle this_oop(THREAD, as_klassOop());
 742   return array_klass_impl(this_oop, or_null, n, THREAD);
 743 }
 744 
 745 klassOop instanceKlass::array_klass_impl(instanceKlassHandle this_oop, bool or_null, int n, TRAPS) {
 746   if (this_oop->array_klasses() == NULL) {
 747     if (or_null) return NULL;
 748 
 749     ResourceMark rm;
 750     JavaThread *jt = (JavaThread *)THREAD;
 751     {
 752       // Atomic creation of array_klasses
 753       MutexLocker mc(Compile_lock, THREAD);   // for vtables
 754       MutexLocker ma(MultiArray_lock, THREAD);
 755 
 756       // Check if update has already taken place
 757       if (this_oop->array_klasses() == NULL) {
 758         objArrayKlassKlass* oakk =
 759           (objArrayKlassKlass*)Universe::objArrayKlassKlassObj()->klass_part();
 760 
 761         klassOop  k = oakk->allocate_objArray_klass(1, this_oop, CHECK_NULL);
 762         this_oop->set_array_klasses(k);
 763       }
 764     }
 765   }
 766   // _this will always be set at this point
 767   objArrayKlass* oak = (objArrayKlass*)this_oop->array_klasses()->klass_part();
 768   if (or_null) {
 769     return oak->array_klass_or_null(n);
 770   }
 771   return oak->array_klass(n, CHECK_NULL);
 772 }
 773 
 774 klassOop instanceKlass::array_klass_impl(bool or_null, TRAPS) {
 775   return array_klass_impl(or_null, 1, THREAD);
 776 }
 777 
 778 void instanceKlass::call_class_initializer(TRAPS) {
 779   instanceKlassHandle ik (THREAD, as_klassOop());
 780   call_class_initializer_impl(ik, THREAD);
 781 }
 782 
 783 static int call_class_initializer_impl_counter = 0;   // for debugging
 784 
 785 methodOop instanceKlass::class_initializer() {
 786   methodOop clinit = find_method(
 787       vmSymbols::class_initializer_name(), vmSymbols::void_method_signature());
 788   if (clinit != NULL && clinit->has_valid_initializer_flags()) {
 789     return clinit;
 790   }
 791   return NULL;
 792 }
 793 
 794 void instanceKlass::call_class_initializer_impl(instanceKlassHandle this_oop, TRAPS) {
 795   methodHandle h_method(THREAD, this_oop->class_initializer());
 796   assert(!this_oop->is_initialized(), "we cannot initialize twice");
 797   if (TraceClassInitialization) {
 798     tty->print("%d Initializing ", call_class_initializer_impl_counter++);
 799     this_oop->name()->print_value();
 800     tty->print_cr("%s (" INTPTR_FORMAT ")", h_method() == NULL ? "(no method)" : "", (address)this_oop());
 801   }
 802   if (h_method() != NULL) {
 803     JavaCallArguments args; // No arguments
 804     JavaValue result(T_VOID);
 805     JavaCalls::call(&result, h_method, &args, CHECK); // Static call (no args)
 806   }
 807 }
 808 
 809 
 810 void instanceKlass::mask_for(methodHandle method, int bci,
 811   InterpreterOopMap* entry_for) {
 812   // Dirty read, then double-check under a lock.
 813   if (_oop_map_cache == NULL) {
 814     // Otherwise, allocate a new one.
 815     MutexLocker x(OopMapCacheAlloc_lock);
 816     // First time use. Allocate a cache in C heap
 817     if (_oop_map_cache == NULL) {
 818       _oop_map_cache = new OopMapCache();
 819     }
 820   }
 821   // _oop_map_cache is constant after init; lookup below does is own locking.
 822   _oop_map_cache->lookup(method, bci, entry_for);
 823 }
 824 
 825 
 826 bool instanceKlass::find_local_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
 827   for (JavaFieldStream fs(as_klassOop()); !fs.done(); fs.next()) {
 828     Symbol* f_name = fs.name();
 829     Symbol* f_sig  = fs.signature();
 830     if (f_name == name && f_sig == sig) {
 831       fd->initialize(as_klassOop(), fs.index());
 832       return true;
 833     }
 834   }
 835   return false;
 836 }
 837 
 838 
 839 void instanceKlass::shared_symbols_iterate(SymbolClosure* closure) {
 840   Klass::shared_symbols_iterate(closure);
 841   closure->do_symbol(&_generic_signature);
 842   closure->do_symbol(&_source_file_name);
 843   closure->do_symbol(&_source_debug_extension);
 844 
 845   for (JavaFieldStream fs(this); !fs.done(); fs.next()) {
 846     int name_index = fs.name_index();
 847     closure->do_symbol(constants()->symbol_at_addr(name_index));
 848     int sig_index  = fs.signature_index();
 849     closure->do_symbol(constants()->symbol_at_addr(sig_index));
 850   }
 851 }
 852 
 853 
 854 klassOop instanceKlass::find_interface_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
 855   const int n = local_interfaces()->length();
 856   for (int i = 0; i < n; i++) {
 857     klassOop intf1 = klassOop(local_interfaces()->obj_at(i));
 858     assert(Klass::cast(intf1)->is_interface(), "just checking type");
 859     // search for field in current interface
 860     if (instanceKlass::cast(intf1)->find_local_field(name, sig, fd)) {
 861       assert(fd->is_static(), "interface field must be static");
 862       return intf1;
 863     }
 864     // search for field in direct superinterfaces
 865     klassOop intf2 = instanceKlass::cast(intf1)->find_interface_field(name, sig, fd);
 866     if (intf2 != NULL) return intf2;
 867   }
 868   // otherwise field lookup fails
 869   return NULL;
 870 }
 871 
 872 
 873 klassOop instanceKlass::find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
 874   // search order according to newest JVM spec (5.4.3.2, p.167).
 875   // 1) search for field in current klass
 876   if (find_local_field(name, sig, fd)) {
 877     return as_klassOop();
 878   }
 879   // 2) search for field recursively in direct superinterfaces
 880   { klassOop intf = find_interface_field(name, sig, fd);
 881     if (intf != NULL) return intf;
 882   }
 883   // 3) apply field lookup recursively if superclass exists
 884   { klassOop supr = super();
 885     if (supr != NULL) return instanceKlass::cast(supr)->find_field(name, sig, fd);
 886   }
 887   // 4) otherwise field lookup fails
 888   return NULL;
 889 }
 890 
 891 
 892 klassOop instanceKlass::find_field(Symbol* name, Symbol* sig, bool is_static, fieldDescriptor* fd) const {
 893   // search order according to newest JVM spec (5.4.3.2, p.167).
 894   // 1) search for field in current klass
 895   if (find_local_field(name, sig, fd)) {
 896     if (fd->is_static() == is_static) return as_klassOop();
 897   }
 898   // 2) search for field recursively in direct superinterfaces
 899   if (is_static) {
 900     klassOop intf = find_interface_field(name, sig, fd);
 901     if (intf != NULL) return intf;
 902   }
 903   // 3) apply field lookup recursively if superclass exists
 904   { klassOop supr = super();
 905     if (supr != NULL) return instanceKlass::cast(supr)->find_field(name, sig, is_static, fd);
 906   }
 907   // 4) otherwise field lookup fails
 908   return NULL;
 909 }
 910 
 911 
 912 bool instanceKlass::find_local_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const {
 913   for (JavaFieldStream fs(as_klassOop()); !fs.done(); fs.next()) {
 914     if (fs.offset() == offset) {
 915       fd->initialize(as_klassOop(), fs.index());
 916       if (fd->is_static() == is_static) return true;
 917     }
 918   }
 919   return false;
 920 }
 921 
 922 
 923 bool instanceKlass::find_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const {
 924   klassOop klass = as_klassOop();
 925   while (klass != NULL) {
 926     if (instanceKlass::cast(klass)->find_local_field_from_offset(offset, is_static, fd)) {
 927       return true;
 928     }
 929     klass = Klass::cast(klass)->super();
 930   }
 931   return false;
 932 }
 933 
 934 
 935 void instanceKlass::methods_do(void f(methodOop method)) {
 936   int len = methods()->length();
 937   for (int index = 0; index < len; index++) {
 938     methodOop m = methodOop(methods()->obj_at(index));
 939     assert(m->is_method(), "must be method");
 940     f(m);
 941   }
 942 }
 943 
 944 
 945 void instanceKlass::do_local_static_fields(FieldClosure* cl) {
 946   for (JavaFieldStream fs(this); !fs.done(); fs.next()) {
 947     if (fs.access_flags().is_static()) {
 948       fieldDescriptor fd;
 949       fd.initialize(as_klassOop(), fs.index());
 950       cl->do_field(&fd);
 951     }
 952   }
 953 }
 954 
 955 
 956 void instanceKlass::do_local_static_fields(void f(fieldDescriptor*, TRAPS), TRAPS) {
 957   instanceKlassHandle h_this(THREAD, as_klassOop());
 958   do_local_static_fields_impl(h_this, f, CHECK);
 959 }
 960 
 961 
 962 void instanceKlass::do_local_static_fields_impl(instanceKlassHandle this_oop, void f(fieldDescriptor* fd, TRAPS), TRAPS) {
 963   for (JavaFieldStream fs(this_oop()); !fs.done(); fs.next()) {
 964     if (fs.access_flags().is_static()) {
 965       fieldDescriptor fd;
 966       fd.initialize(this_oop(), fs.index());
 967       f(&fd, CHECK);
 968     }
 969   }
 970 }
 971 
 972 
 973 static int compare_fields_by_offset(int* a, int* b) {
 974   return a[0] - b[0];
 975 }
 976 
 977 void instanceKlass::do_nonstatic_fields(FieldClosure* cl) {
 978   instanceKlass* super = superklass();
 979   if (super != NULL) {
 980     super->do_nonstatic_fields(cl);
 981   }
 982   fieldDescriptor fd;
 983   int length = java_fields_count();
 984   // In DebugInfo nonstatic fields are sorted by offset.
 985   int* fields_sorted = NEW_C_HEAP_ARRAY(int, 2*(length+1));
 986   int j = 0;
 987   for (int i = 0; i < length; i += 1) {
 988     fd.initialize(as_klassOop(), i);
 989     if (!fd.is_static()) {
 990       fields_sorted[j + 0] = fd.offset();
 991       fields_sorted[j + 1] = i;
 992       j += 2;
 993     }
 994   }
 995   if (j > 0) {
 996     length = j;
 997     // _sort_Fn is defined in growableArray.hpp.
 998     qsort(fields_sorted, length/2, 2*sizeof(int), (_sort_Fn)compare_fields_by_offset);
 999     for (int i = 0; i < length; i += 2) {
1000       fd.initialize(as_klassOop(), fields_sorted[i + 1]);
1001       assert(!fd.is_static() && fd.offset() == fields_sorted[i], "only nonstatic fields");
1002       cl->do_field(&fd);
1003     }
1004   }
1005   FREE_C_HEAP_ARRAY(int, fields_sorted);
1006 }
1007 
1008 
1009 void instanceKlass::array_klasses_do(void f(klassOop k)) {
1010   if (array_klasses() != NULL)
1011     arrayKlass::cast(array_klasses())->array_klasses_do(f);
1012 }
1013 
1014 
1015 void instanceKlass::with_array_klasses_do(void f(klassOop k)) {
1016   f(as_klassOop());
1017   array_klasses_do(f);
1018 }
1019 
1020 #ifdef ASSERT
1021 static int linear_search(objArrayOop methods, Symbol* name, Symbol* signature) {
1022   int len = methods->length();
1023   for (int index = 0; index < len; index++) {
1024     methodOop m = (methodOop)(methods->obj_at(index));
1025     assert(m->is_method(), "must be method");
1026     if (m->signature() == signature && m->name() == name) {
1027        return index;
1028     }
1029   }
1030   return -1;
1031 }
1032 #endif
1033 
1034 methodOop instanceKlass::find_method(Symbol* name, Symbol* signature) const {
1035   return instanceKlass::find_method(methods(), name, signature);
1036 }
1037 
1038 methodOop instanceKlass::find_method(objArrayOop methods, Symbol* name, Symbol* signature) {
1039   int len = methods->length();
1040   // methods are sorted, so do binary search
1041   int l = 0;
1042   int h = len - 1;
1043   while (l <= h) {
1044     int mid = (l + h) >> 1;
1045     methodOop m = (methodOop)methods->obj_at(mid);
1046     assert(m->is_method(), "must be method");
1047     int res = m->name()->fast_compare(name);
1048     if (res == 0) {
1049       // found matching name; do linear search to find matching signature
1050       // first, quick check for common case
1051       if (m->signature() == signature) return m;
1052       // search downwards through overloaded methods
1053       int i;
1054       for (i = mid - 1; i >= l; i--) {
1055         methodOop m = (methodOop)methods->obj_at(i);
1056         assert(m->is_method(), "must be method");
1057         if (m->name() != name) break;
1058         if (m->signature() == signature) return m;
1059       }
1060       // search upwards
1061       for (i = mid + 1; i <= h; i++) {
1062         methodOop m = (methodOop)methods->obj_at(i);
1063         assert(m->is_method(), "must be method");
1064         if (m->name() != name) break;
1065         if (m->signature() == signature) return m;
1066       }
1067       // not found
1068 #ifdef ASSERT
1069       int index = linear_search(methods, name, signature);
1070       assert(index == -1, err_msg("binary search should have found entry %d", index));
1071 #endif
1072       return NULL;
1073     } else if (res < 0) {
1074       l = mid + 1;
1075     } else {
1076       h = mid - 1;
1077     }
1078   }
1079 #ifdef ASSERT
1080   int index = linear_search(methods, name, signature);
1081   assert(index == -1, err_msg("binary search should have found entry %d", index));
1082 #endif
1083   return NULL;
1084 }
1085 
1086 methodOop instanceKlass::uncached_lookup_method(Symbol* name, Symbol* signature) const {
1087   klassOop klass = as_klassOop();
1088   while (klass != NULL) {
1089     methodOop method = instanceKlass::cast(klass)->find_method(name, signature);
1090     if (method != NULL) return method;
1091     klass = instanceKlass::cast(klass)->super();
1092   }
1093   return NULL;
1094 }
1095 
1096 // lookup a method in all the interfaces that this class implements
1097 methodOop instanceKlass::lookup_method_in_all_interfaces(Symbol* name,
1098                                                          Symbol* signature) const {
1099   objArrayOop all_ifs = instanceKlass::cast(as_klassOop())->transitive_interfaces();
1100   int num_ifs = all_ifs->length();
1101   instanceKlass *ik = NULL;
1102   for (int i = 0; i < num_ifs; i++) {
1103     ik = instanceKlass::cast(klassOop(all_ifs->obj_at(i)));
1104     methodOop m = ik->lookup_method(name, signature);
1105     if (m != NULL) {
1106       return m;
1107     }
1108   }
1109   return NULL;
1110 }
1111 
1112 /* jni_id_for_impl for jfieldIds only */
1113 JNIid* instanceKlass::jni_id_for_impl(instanceKlassHandle this_oop, int offset) {
1114   MutexLocker ml(JfieldIdCreation_lock);
1115   // Retry lookup after we got the lock
1116   JNIid* probe = this_oop->jni_ids() == NULL ? NULL : this_oop->jni_ids()->find(offset);
1117   if (probe == NULL) {
1118     // Slow case, allocate new static field identifier
1119     probe = new JNIid(this_oop->as_klassOop(), offset, this_oop->jni_ids());
1120     this_oop->set_jni_ids(probe);
1121   }
1122   return probe;
1123 }
1124 
1125 
1126 /* jni_id_for for jfieldIds only */
1127 JNIid* instanceKlass::jni_id_for(int offset) {
1128   JNIid* probe = jni_ids() == NULL ? NULL : jni_ids()->find(offset);
1129   if (probe == NULL) {
1130     probe = jni_id_for_impl(this->as_klassOop(), offset);
1131   }
1132   return probe;
1133 }
1134 
1135 
1136 // Lookup or create a jmethodID.
1137 // This code is called by the VMThread and JavaThreads so the
1138 // locking has to be done very carefully to avoid deadlocks
1139 // and/or other cache consistency problems.
1140 //
1141 jmethodID instanceKlass::get_jmethod_id(instanceKlassHandle ik_h, methodHandle method_h) {
1142   size_t idnum = (size_t)method_h->method_idnum();
1143   jmethodID* jmeths = ik_h->methods_jmethod_ids_acquire();
1144   size_t length = 0;
1145   jmethodID id = NULL;
1146 
1147   // We use a double-check locking idiom here because this cache is
1148   // performance sensitive. In the normal system, this cache only
1149   // transitions from NULL to non-NULL which is safe because we use
1150   // release_set_methods_jmethod_ids() to advertise the new cache.
1151   // A partially constructed cache should never be seen by a racing
1152   // thread. We also use release_store_ptr() to save a new jmethodID
1153   // in the cache so a partially constructed jmethodID should never be
1154   // seen either. Cache reads of existing jmethodIDs proceed without a
1155   // lock, but cache writes of a new jmethodID requires uniqueness and
1156   // creation of the cache itself requires no leaks so a lock is
1157   // generally acquired in those two cases.
1158   //
1159   // If the RedefineClasses() API has been used, then this cache can
1160   // grow and we'll have transitions from non-NULL to bigger non-NULL.
1161   // Cache creation requires no leaks and we require safety between all
1162   // cache accesses and freeing of the old cache so a lock is generally
1163   // acquired when the RedefineClasses() API has been used.
1164 
1165   if (jmeths != NULL) {
1166     // the cache already exists
1167     if (!ik_h->idnum_can_increment()) {
1168       // the cache can't grow so we can just get the current values
1169       get_jmethod_id_length_value(jmeths, idnum, &length, &id);
1170     } else {
1171       // cache can grow so we have to be more careful
1172       if (Threads::number_of_threads() == 0 ||
1173           SafepointSynchronize::is_at_safepoint()) {
1174         // we're single threaded or at a safepoint - no locking needed
1175         get_jmethod_id_length_value(jmeths, idnum, &length, &id);
1176       } else {
1177         MutexLocker ml(JmethodIdCreation_lock);
1178         get_jmethod_id_length_value(jmeths, idnum, &length, &id);
1179       }
1180     }
1181   }
1182   // implied else:
1183   // we need to allocate a cache so default length and id values are good
1184 
1185   if (jmeths == NULL ||   // no cache yet
1186       length <= idnum ||  // cache is too short
1187       id == NULL) {       // cache doesn't contain entry
1188 
1189     // This function can be called by the VMThread so we have to do all
1190     // things that might block on a safepoint before grabbing the lock.
1191     // Otherwise, we can deadlock with the VMThread or have a cache
1192     // consistency issue. These vars keep track of what we might have
1193     // to free after the lock is dropped.
1194     jmethodID  to_dealloc_id     = NULL;
1195     jmethodID* to_dealloc_jmeths = NULL;
1196 
1197     // may not allocate new_jmeths or use it if we allocate it
1198     jmethodID* new_jmeths = NULL;
1199     if (length <= idnum) {
1200       // allocate a new cache that might be used
1201       size_t size = MAX2(idnum+1, (size_t)ik_h->idnum_allocated_count());
1202       new_jmeths = NEW_C_HEAP_ARRAY(jmethodID, size+1);
1203       memset(new_jmeths, 0, (size+1)*sizeof(jmethodID));
1204       // cache size is stored in element[0], other elements offset by one
1205       new_jmeths[0] = (jmethodID)size;
1206     }
1207 
1208     // allocate a new jmethodID that might be used
1209     jmethodID new_id = NULL;
1210     if (method_h->is_old() && !method_h->is_obsolete()) {
1211       // The method passed in is old (but not obsolete), we need to use the current version
1212       methodOop current_method = ik_h->method_with_idnum((int)idnum);
1213       assert(current_method != NULL, "old and but not obsolete, so should exist");
1214       methodHandle current_method_h(current_method == NULL? method_h() : current_method);
1215       new_id = JNIHandles::make_jmethod_id(current_method_h);
1216     } else {
1217       // It is the current version of the method or an obsolete method,
1218       // use the version passed in
1219       new_id = JNIHandles::make_jmethod_id(method_h);
1220     }
1221 
1222     if (Threads::number_of_threads() == 0 ||
1223         SafepointSynchronize::is_at_safepoint()) {
1224       // we're single threaded or at a safepoint - no locking needed
1225       id = get_jmethod_id_fetch_or_update(ik_h, idnum, new_id, new_jmeths,
1226                                           &to_dealloc_id, &to_dealloc_jmeths);
1227     } else {
1228       MutexLocker ml(JmethodIdCreation_lock);
1229       id = get_jmethod_id_fetch_or_update(ik_h, idnum, new_id, new_jmeths,
1230                                           &to_dealloc_id, &to_dealloc_jmeths);
1231     }
1232 
1233     // The lock has been dropped so we can free resources.
1234     // Free up either the old cache or the new cache if we allocated one.
1235     if (to_dealloc_jmeths != NULL) {
1236       FreeHeap(to_dealloc_jmeths);
1237     }
1238     // free up the new ID since it wasn't needed
1239     if (to_dealloc_id != NULL) {
1240       JNIHandles::destroy_jmethod_id(to_dealloc_id);
1241     }
1242   }
1243   return id;
1244 }
1245 
1246 
1247 // Common code to fetch the jmethodID from the cache or update the
1248 // cache with the new jmethodID. This function should never do anything
1249 // that causes the caller to go to a safepoint or we can deadlock with
1250 // the VMThread or have cache consistency issues.
1251 //
1252 jmethodID instanceKlass::get_jmethod_id_fetch_or_update(
1253             instanceKlassHandle ik_h, size_t idnum, jmethodID new_id,
1254             jmethodID* new_jmeths, jmethodID* to_dealloc_id_p,
1255             jmethodID** to_dealloc_jmeths_p) {
1256   assert(new_id != NULL, "sanity check");
1257   assert(to_dealloc_id_p != NULL, "sanity check");
1258   assert(to_dealloc_jmeths_p != NULL, "sanity check");
1259   assert(Threads::number_of_threads() == 0 ||
1260          SafepointSynchronize::is_at_safepoint() ||
1261          JmethodIdCreation_lock->owned_by_self(), "sanity check");
1262 
1263   // reacquire the cache - we are locked, single threaded or at a safepoint
1264   jmethodID* jmeths = ik_h->methods_jmethod_ids_acquire();
1265   jmethodID  id     = NULL;
1266   size_t     length = 0;
1267 
1268   if (jmeths == NULL ||                         // no cache yet
1269       (length = (size_t)jmeths[0]) <= idnum) {  // cache is too short
1270     if (jmeths != NULL) {
1271       // copy any existing entries from the old cache
1272       for (size_t index = 0; index < length; index++) {
1273         new_jmeths[index+1] = jmeths[index+1];
1274       }
1275       *to_dealloc_jmeths_p = jmeths;  // save old cache for later delete
1276     }
1277     ik_h->release_set_methods_jmethod_ids(jmeths = new_jmeths);
1278   } else {
1279     // fetch jmethodID (if any) from the existing cache
1280     id = jmeths[idnum+1];
1281     *to_dealloc_jmeths_p = new_jmeths;  // save new cache for later delete
1282   }
1283   if (id == NULL) {
1284     // No matching jmethodID in the existing cache or we have a new
1285     // cache or we just grew the cache. This cache write is done here
1286     // by the first thread to win the foot race because a jmethodID
1287     // needs to be unique once it is generally available.
1288     id = new_id;
1289 
1290     // The jmethodID cache can be read while unlocked so we have to
1291     // make sure the new jmethodID is complete before installing it
1292     // in the cache.
1293     OrderAccess::release_store_ptr(&jmeths[idnum+1], id);
1294   } else {
1295     *to_dealloc_id_p = new_id; // save new id for later delete
1296   }
1297   return id;
1298 }
1299 
1300 
1301 // Common code to get the jmethodID cache length and the jmethodID
1302 // value at index idnum if there is one.
1303 //
1304 void instanceKlass::get_jmethod_id_length_value(jmethodID* cache,
1305        size_t idnum, size_t *length_p, jmethodID* id_p) {
1306   assert(cache != NULL, "sanity check");
1307   assert(length_p != NULL, "sanity check");
1308   assert(id_p != NULL, "sanity check");
1309 
1310   // cache size is stored in element[0], other elements offset by one
1311   *length_p = (size_t)cache[0];
1312   if (*length_p <= idnum) {  // cache is too short
1313     *id_p = NULL;
1314   } else {
1315     *id_p = cache[idnum+1];  // fetch jmethodID (if any)
1316   }
1317 }
1318 
1319 
1320 // Lookup a jmethodID, NULL if not found.  Do no blocking, no allocations, no handles
1321 jmethodID instanceKlass::jmethod_id_or_null(methodOop method) {
1322   size_t idnum = (size_t)method->method_idnum();
1323   jmethodID* jmeths = methods_jmethod_ids_acquire();
1324   size_t length;                                // length assigned as debugging crumb
1325   jmethodID id = NULL;
1326   if (jmeths != NULL &&                         // If there is a cache
1327       (length = (size_t)jmeths[0]) > idnum) {   // and if it is long enough,
1328     id = jmeths[idnum+1];                       // Look up the id (may be NULL)
1329   }
1330   return id;
1331 }
1332 
1333 
1334 // Cache an itable index
1335 void instanceKlass::set_cached_itable_index(size_t idnum, int index) {
1336   int* indices = methods_cached_itable_indices_acquire();
1337   int* to_dealloc_indices = NULL;
1338 
1339   // We use a double-check locking idiom here because this cache is
1340   // performance sensitive. In the normal system, this cache only
1341   // transitions from NULL to non-NULL which is safe because we use
1342   // release_set_methods_cached_itable_indices() to advertise the
1343   // new cache. A partially constructed cache should never be seen
1344   // by a racing thread. Cache reads and writes proceed without a
1345   // lock, but creation of the cache itself requires no leaks so a
1346   // lock is generally acquired in that case.
1347   //
1348   // If the RedefineClasses() API has been used, then this cache can
1349   // grow and we'll have transitions from non-NULL to bigger non-NULL.
1350   // Cache creation requires no leaks and we require safety between all
1351   // cache accesses and freeing of the old cache so a lock is generally
1352   // acquired when the RedefineClasses() API has been used.
1353 
1354   if (indices == NULL || idnum_can_increment()) {
1355     // we need a cache or the cache can grow
1356     MutexLocker ml(JNICachedItableIndex_lock);
1357     // reacquire the cache to see if another thread already did the work
1358     indices = methods_cached_itable_indices_acquire();
1359     size_t length = 0;
1360     // cache size is stored in element[0], other elements offset by one
1361     if (indices == NULL || (length = (size_t)indices[0]) <= idnum) {
1362       size_t size = MAX2(idnum+1, (size_t)idnum_allocated_count());
1363       int* new_indices = NEW_C_HEAP_ARRAY(int, size+1);
1364       new_indices[0] = (int)size;
1365       // copy any existing entries
1366       size_t i;
1367       for (i = 0; i < length; i++) {
1368         new_indices[i+1] = indices[i+1];
1369       }
1370       // Set all the rest to -1
1371       for (i = length; i < size; i++) {
1372         new_indices[i+1] = -1;
1373       }
1374       if (indices != NULL) {
1375         // We have an old cache to delete so save it for after we
1376         // drop the lock.
1377         to_dealloc_indices = indices;
1378       }
1379       release_set_methods_cached_itable_indices(indices = new_indices);
1380     }
1381 
1382     if (idnum_can_increment()) {
1383       // this cache can grow so we have to write to it safely
1384       indices[idnum+1] = index;
1385     }
1386   } else {
1387     CHECK_UNHANDLED_OOPS_ONLY(Thread::current()->clear_unhandled_oops());
1388   }
1389 
1390   if (!idnum_can_increment()) {
1391     // The cache cannot grow and this JNI itable index value does not
1392     // have to be unique like a jmethodID. If there is a race to set it,
1393     // it doesn't matter.
1394     indices[idnum+1] = index;
1395   }
1396 
1397   if (to_dealloc_indices != NULL) {
1398     // we allocated a new cache so free the old one
1399     FreeHeap(to_dealloc_indices);
1400   }
1401 }
1402 
1403 
1404 // Retrieve a cached itable index
1405 int instanceKlass::cached_itable_index(size_t idnum) {
1406   int* indices = methods_cached_itable_indices_acquire();
1407   if (indices != NULL && ((size_t)indices[0]) > idnum) {
1408      // indices exist and are long enough, retrieve possible cached
1409     return indices[idnum+1];
1410   }
1411   return -1;
1412 }
1413 
1414 
1415 //
1416 // Walk the list of dependent nmethods searching for nmethods which
1417 // are dependent on the changes that were passed in and mark them for
1418 // deoptimization.  Returns the number of nmethods found.
1419 //
1420 int instanceKlass::mark_dependent_nmethods(DepChange& changes) {
1421   assert_locked_or_safepoint(CodeCache_lock);
1422   int found = 0;
1423   nmethodBucket* b = _dependencies;
1424   while (b != NULL) {
1425     nmethod* nm = b->get_nmethod();
1426     // since dependencies aren't removed until an nmethod becomes a zombie,
1427     // the dependency list may contain nmethods which aren't alive.
1428     if (nm->is_alive() && !nm->is_marked_for_deoptimization() && nm->check_dependency_on(changes)) {
1429       if (TraceDependencies) {
1430         ResourceMark rm;
1431         tty->print_cr("Marked for deoptimization");
1432         tty->print_cr("  context = %s", this->external_name());
1433         changes.print();
1434         nm->print();
1435         nm->print_dependencies();
1436       }
1437       nm->mark_for_deoptimization();
1438       found++;
1439     }
1440     b = b->next();
1441   }
1442   return found;
1443 }
1444 
1445 
1446 //
1447 // Add an nmethodBucket to the list of dependencies for this nmethod.
1448 // It's possible that an nmethod has multiple dependencies on this klass
1449 // so a count is kept for each bucket to guarantee that creation and
1450 // deletion of dependencies is consistent.
1451 //
1452 void instanceKlass::add_dependent_nmethod(nmethod* nm) {
1453   assert_locked_or_safepoint(CodeCache_lock);
1454   nmethodBucket* b = _dependencies;
1455   nmethodBucket* last = NULL;
1456   while (b != NULL) {
1457     if (nm == b->get_nmethod()) {
1458       b->increment();
1459       return;
1460     }
1461     b = b->next();
1462   }
1463   _dependencies = new nmethodBucket(nm, _dependencies);
1464 }
1465 
1466 
1467 //
1468 // Decrement count of the nmethod in the dependency list and remove
1469 // the bucket competely when the count goes to 0.  This method must
1470 // find a corresponding bucket otherwise there's a bug in the
1471 // recording of dependecies.
1472 //
1473 void instanceKlass::remove_dependent_nmethod(nmethod* nm) {
1474   assert_locked_or_safepoint(CodeCache_lock);
1475   nmethodBucket* b = _dependencies;
1476   nmethodBucket* last = NULL;
1477   while (b != NULL) {
1478     if (nm == b->get_nmethod()) {
1479       if (b->decrement() == 0) {
1480         if (last == NULL) {
1481           _dependencies = b->next();
1482         } else {
1483           last->set_next(b->next());
1484         }
1485         delete b;
1486       }
1487       return;
1488     }
1489     last = b;
1490     b = b->next();
1491   }
1492 #ifdef ASSERT
1493   tty->print_cr("### %s can't find dependent nmethod:", this->external_name());
1494   nm->print();
1495 #endif // ASSERT
1496   ShouldNotReachHere();
1497 }
1498 
1499 
1500 #ifndef PRODUCT
1501 void instanceKlass::print_dependent_nmethods(bool verbose) {
1502   nmethodBucket* b = _dependencies;
1503   int idx = 0;
1504   while (b != NULL) {
1505     nmethod* nm = b->get_nmethod();
1506     tty->print("[%d] count=%d { ", idx++, b->count());
1507     if (!verbose) {
1508       nm->print_on(tty, "nmethod");
1509       tty->print_cr(" } ");
1510     } else {
1511       nm->print();
1512       nm->print_dependencies();
1513       tty->print_cr("--- } ");
1514     }
1515     b = b->next();
1516   }
1517 }
1518 
1519 
1520 bool instanceKlass::is_dependent_nmethod(nmethod* nm) {
1521   nmethodBucket* b = _dependencies;
1522   while (b != NULL) {
1523     if (nm == b->get_nmethod()) {
1524       return true;
1525     }
1526     b = b->next();
1527   }
1528   return false;
1529 }
1530 #endif //PRODUCT
1531 
1532 
1533 #ifdef ASSERT
1534 template <class T> void assert_is_in(T *p) {
1535   T heap_oop = oopDesc::load_heap_oop(p);
1536   if (!oopDesc::is_null(heap_oop)) {
1537     oop o = oopDesc::decode_heap_oop_not_null(heap_oop);
1538     assert(Universe::heap()->is_in(o), "should be in heap");
1539   }
1540 }
1541 template <class T> void assert_is_in_closed_subset(T *p) {
1542   T heap_oop = oopDesc::load_heap_oop(p);
1543   if (!oopDesc::is_null(heap_oop)) {
1544     oop o = oopDesc::decode_heap_oop_not_null(heap_oop);
1545     assert(Universe::heap()->is_in_closed_subset(o), "should be in closed");
1546   }
1547 }
1548 template <class T> void assert_is_in_reserved(T *p) {
1549   T heap_oop = oopDesc::load_heap_oop(p);
1550   if (!oopDesc::is_null(heap_oop)) {
1551     oop o = oopDesc::decode_heap_oop_not_null(heap_oop);
1552     assert(Universe::heap()->is_in_reserved(o), "should be in reserved");
1553   }
1554 }
1555 template <class T> void assert_nothing(T *p) {}
1556 
1557 #else
1558 template <class T> void assert_is_in(T *p) {}
1559 template <class T> void assert_is_in_closed_subset(T *p) {}
1560 template <class T> void assert_is_in_reserved(T *p) {}
1561 template <class T> void assert_nothing(T *p) {}
1562 #endif // ASSERT
1563 
1564 //
1565 // Macros that iterate over areas of oops which are specialized on type of
1566 // oop pointer either narrow or wide, depending on UseCompressedOops
1567 //
1568 // Parameters are:
1569 //   T         - type of oop to point to (either oop or narrowOop)
1570 //   start_p   - starting pointer for region to iterate over
1571 //   count     - number of oops or narrowOops to iterate over
1572 //   do_oop    - action to perform on each oop (it's arbitrary C code which
1573 //               makes it more efficient to put in a macro rather than making
1574 //               it a template function)
1575 //   assert_fn - assert function which is template function because performance
1576 //               doesn't matter when enabled.
1577 #define InstanceKlass_SPECIALIZED_OOP_ITERATE( \
1578   T, start_p, count, do_oop,                \
1579   assert_fn)                                \
1580 {                                           \
1581   T* p         = (T*)(start_p);             \
1582   T* const end = p + (count);               \
1583   while (p < end) {                         \
1584     (assert_fn)(p);                         \
1585     do_oop;                                 \
1586     ++p;                                    \
1587   }                                         \
1588 }
1589 
1590 #define InstanceKlass_SPECIALIZED_OOP_REVERSE_ITERATE( \
1591   T, start_p, count, do_oop,                \
1592   assert_fn)                                \
1593 {                                           \
1594   T* const start = (T*)(start_p);           \
1595   T*       p     = start + (count);         \
1596   while (start < p) {                       \
1597     --p;                                    \
1598     (assert_fn)(p);                         \
1599     do_oop;                                 \
1600   }                                         \
1601 }
1602 
1603 #define InstanceKlass_SPECIALIZED_BOUNDED_OOP_ITERATE( \
1604   T, start_p, count, low, high,             \
1605   do_oop, assert_fn)                        \
1606 {                                           \
1607   T* const l = (T*)(low);                   \
1608   T* const h = (T*)(high);                  \
1609   assert(mask_bits((intptr_t)l, sizeof(T)-1) == 0 && \
1610          mask_bits((intptr_t)h, sizeof(T)-1) == 0,   \
1611          "bounded region must be properly aligned"); \
1612   T* p       = (T*)(start_p);               \
1613   T* end     = p + (count);                 \
1614   if (p < l) p = l;                         \
1615   if (end > h) end = h;                     \
1616   while (p < end) {                         \
1617     (assert_fn)(p);                         \
1618     do_oop;                                 \
1619     ++p;                                    \
1620   }                                         \
1621 }
1622 
1623 
1624 // The following macros call specialized macros, passing either oop or
1625 // narrowOop as the specialization type.  These test the UseCompressedOops
1626 // flag.
1627 #define InstanceKlass_OOP_MAP_ITERATE(obj, do_oop, assert_fn)            \
1628 {                                                                        \
1629   /* Compute oopmap block range. The common case                         \
1630      is nonstatic_oop_map_size == 1. */                                  \
1631   OopMapBlock* map           = start_of_nonstatic_oop_maps();            \
1632   OopMapBlock* const end_map = map + nonstatic_oop_map_count();          \
1633   if (UseCompressedOops) {                                               \
1634     while (map < end_map) {                                              \
1635       InstanceKlass_SPECIALIZED_OOP_ITERATE(narrowOop,                   \
1636         obj->obj_field_addr<narrowOop>(map->offset()), map->count(),     \
1637         do_oop, assert_fn)                                               \
1638       ++map;                                                             \
1639     }                                                                    \
1640   } else {                                                               \
1641     while (map < end_map) {                                              \
1642       InstanceKlass_SPECIALIZED_OOP_ITERATE(oop,                         \
1643         obj->obj_field_addr<oop>(map->offset()), map->count(),           \
1644         do_oop, assert_fn)                                               \
1645       ++map;                                                             \
1646     }                                                                    \
1647   }                                                                      \
1648 }
1649 
1650 #define InstanceKlass_OOP_MAP_REVERSE_ITERATE(obj, do_oop, assert_fn)    \
1651 {                                                                        \
1652   OopMapBlock* const start_map = start_of_nonstatic_oop_maps();          \
1653   OopMapBlock* map             = start_map + nonstatic_oop_map_count();  \
1654   if (UseCompressedOops) {                                               \
1655     while (start_map < map) {                                            \
1656       --map;                                                             \
1657       InstanceKlass_SPECIALIZED_OOP_REVERSE_ITERATE(narrowOop,           \
1658         obj->obj_field_addr<narrowOop>(map->offset()), map->count(),     \
1659         do_oop, assert_fn)                                               \
1660     }                                                                    \
1661   } else {                                                               \
1662     while (start_map < map) {                                            \
1663       --map;                                                             \
1664       InstanceKlass_SPECIALIZED_OOP_REVERSE_ITERATE(oop,                 \
1665         obj->obj_field_addr<oop>(map->offset()), map->count(),           \
1666         do_oop, assert_fn)                                               \
1667     }                                                                    \
1668   }                                                                      \
1669 }
1670 
1671 #define InstanceKlass_BOUNDED_OOP_MAP_ITERATE(obj, low, high, do_oop,    \
1672                                               assert_fn)                 \
1673 {                                                                        \
1674   /* Compute oopmap block range. The common case is                      \
1675      nonstatic_oop_map_size == 1, so we accept the                       \
1676      usually non-existent extra overhead of examining                    \
1677      all the maps. */                                                    \
1678   OopMapBlock* map           = start_of_nonstatic_oop_maps();            \
1679   OopMapBlock* const end_map = map + nonstatic_oop_map_count();          \
1680   if (UseCompressedOops) {                                               \
1681     while (map < end_map) {                                              \
1682       InstanceKlass_SPECIALIZED_BOUNDED_OOP_ITERATE(narrowOop,           \
1683         obj->obj_field_addr<narrowOop>(map->offset()), map->count(),     \
1684         low, high,                                                       \
1685         do_oop, assert_fn)                                               \
1686       ++map;                                                             \
1687     }                                                                    \
1688   } else {                                                               \
1689     while (map < end_map) {                                              \
1690       InstanceKlass_SPECIALIZED_BOUNDED_OOP_ITERATE(oop,                 \
1691         obj->obj_field_addr<oop>(map->offset()), map->count(),           \
1692         low, high,                                                       \
1693         do_oop, assert_fn)                                               \
1694       ++map;                                                             \
1695     }                                                                    \
1696   }                                                                      \
1697 }
1698 
1699 void instanceKlass::oop_follow_contents(oop obj) {
1700   assert(obj != NULL, "can't follow the content of NULL object");
1701   obj->follow_header();
1702   InstanceKlass_OOP_MAP_ITERATE( \
1703     obj, \
1704     MarkSweep::mark_and_push(p), \
1705     assert_is_in_closed_subset)
1706 }
1707 
1708 #ifndef SERIALGC
1709 void instanceKlass::oop_follow_contents(ParCompactionManager* cm,
1710                                         oop obj) {
1711   assert(obj != NULL, "can't follow the content of NULL object");
1712   obj->follow_header(cm);
1713   InstanceKlass_OOP_MAP_ITERATE( \
1714     obj, \
1715     PSParallelCompact::mark_and_push(cm, p), \
1716     assert_is_in)
1717 }
1718 #endif // SERIALGC
1719 
1720 // closure's do_header() method dicates whether the given closure should be
1721 // applied to the klass ptr in the object header.
1722 
1723 #define InstanceKlass_OOP_OOP_ITERATE_DEFN(OopClosureType, nv_suffix)        \
1724                                                                              \
1725 int instanceKlass::oop_oop_iterate##nv_suffix(oop obj, OopClosureType* closure) { \
1726   SpecializationStats::record_iterate_call##nv_suffix(SpecializationStats::ik);\
1727   /* header */                                                          \
1728   if (closure->do_header()) {                                           \
1729     obj->oop_iterate_header(closure);                                   \
1730   }                                                                     \
1731   InstanceKlass_OOP_MAP_ITERATE(                                        \
1732     obj,                                                                \
1733     SpecializationStats::                                               \
1734       record_do_oop_call##nv_suffix(SpecializationStats::ik);           \
1735     (closure)->do_oop##nv_suffix(p),                                    \
1736     assert_is_in_closed_subset)                                         \
1737   return size_helper();                                                 \
1738 }
1739 
1740 #ifndef SERIALGC
1741 #define InstanceKlass_OOP_OOP_ITERATE_BACKWARDS_DEFN(OopClosureType, nv_suffix) \
1742                                                                                 \
1743 int instanceKlass::oop_oop_iterate_backwards##nv_suffix(oop obj,                \
1744                                               OopClosureType* closure) {        \
1745   SpecializationStats::record_iterate_call##nv_suffix(SpecializationStats::ik); \
1746   /* header */                                                                  \
1747   if (closure->do_header()) {                                                   \
1748     obj->oop_iterate_header(closure);                                           \
1749   }                                                                             \
1750   /* instance variables */                                                      \
1751   InstanceKlass_OOP_MAP_REVERSE_ITERATE(                                        \
1752     obj,                                                                        \
1753     SpecializationStats::record_do_oop_call##nv_suffix(SpecializationStats::ik);\
1754     (closure)->do_oop##nv_suffix(p),                                            \
1755     assert_is_in_closed_subset)                                                 \
1756    return size_helper();                                                        \
1757 }
1758 #endif // !SERIALGC
1759 
1760 #define InstanceKlass_OOP_OOP_ITERATE_DEFN_m(OopClosureType, nv_suffix) \
1761                                                                         \
1762 int instanceKlass::oop_oop_iterate##nv_suffix##_m(oop obj,              \
1763                                                   OopClosureType* closure, \
1764                                                   MemRegion mr) {          \
1765   SpecializationStats::record_iterate_call##nv_suffix(SpecializationStats::ik);\
1766   if (closure->do_header()) {                                            \
1767     obj->oop_iterate_header(closure, mr);                                \
1768   }                                                                      \
1769   InstanceKlass_BOUNDED_OOP_MAP_ITERATE(                                 \
1770     obj, mr.start(), mr.end(),                                           \
1771     (closure)->do_oop##nv_suffix(p),                                     \
1772     assert_is_in_closed_subset)                                          \
1773   return size_helper();                                                  \
1774 }
1775 
1776 ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceKlass_OOP_OOP_ITERATE_DEFN)
1777 ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceKlass_OOP_OOP_ITERATE_DEFN)
1778 ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceKlass_OOP_OOP_ITERATE_DEFN_m)
1779 ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceKlass_OOP_OOP_ITERATE_DEFN_m)
1780 #ifndef SERIALGC
1781 ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceKlass_OOP_OOP_ITERATE_BACKWARDS_DEFN)
1782 ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceKlass_OOP_OOP_ITERATE_BACKWARDS_DEFN)
1783 #endif // !SERIALGC
1784 
1785 int instanceKlass::oop_adjust_pointers(oop obj) {
1786   int size = size_helper();
1787   InstanceKlass_OOP_MAP_ITERATE( \
1788     obj, \
1789     MarkSweep::adjust_pointer(p), \
1790     assert_is_in)
1791   obj->adjust_header();
1792   return size;
1793 }
1794 
1795 #ifndef SERIALGC
1796 void instanceKlass::oop_push_contents(PSPromotionManager* pm, oop obj) {
1797   InstanceKlass_OOP_MAP_REVERSE_ITERATE( \
1798     obj, \
1799     if (PSScavenge::should_scavenge(p)) { \
1800       pm->claim_or_forward_depth(p); \
1801     }, \
1802     assert_nothing )
1803 }
1804 
1805 int instanceKlass::oop_update_pointers(ParCompactionManager* cm, oop obj) {
1806   InstanceKlass_OOP_MAP_ITERATE( \
1807     obj, \
1808     PSParallelCompact::adjust_pointer(p), \
1809     assert_nothing)
1810   return size_helper();
1811 }
1812 
1813 #endif // SERIALGC
1814 
1815 // This klass is alive but the implementor link is not followed/updated.
1816 // Subklass and sibling links are handled by Klass::follow_weak_klass_links
1817 
1818 void instanceKlass::follow_weak_klass_links(
1819   BoolObjectClosure* is_alive, OopClosure* keep_alive) {
1820   assert(is_alive->do_object_b(as_klassOop()), "this oop should be live");
1821   if (ClassUnloading) {
1822     for (int i = 0; i < implementors_limit; i++) {
1823       klassOop impl = _implementors[i];
1824       if (impl == NULL)  break;  // no more in the list
1825       if (!is_alive->do_object_b(impl)) {
1826         // remove this guy from the list by overwriting him with the tail
1827         int lasti = --_nof_implementors;
1828         assert(lasti >= i && lasti < implementors_limit, "just checking");
1829         _implementors[i] = _implementors[lasti];
1830         _implementors[lasti] = NULL;
1831         --i; // rerun the loop at this index
1832       }
1833     }
1834   } else {
1835     for (int i = 0; i < implementors_limit; i++) {
1836       keep_alive->do_oop(&adr_implementors()[i]);
1837     }
1838   }
1839   Klass::follow_weak_klass_links(is_alive, keep_alive);
1840 }
1841 
1842 void instanceKlass::remove_unshareable_info() {
1843   Klass::remove_unshareable_info();
1844   init_implementor();
1845 }
1846 
1847 static void clear_all_breakpoints(methodOop m) {
1848   m->clear_all_breakpoints();
1849 }
1850 
1851 void instanceKlass::release_C_heap_structures() {
1852   // Deallocate oop map cache
1853   if (_oop_map_cache != NULL) {
1854     delete _oop_map_cache;
1855     _oop_map_cache = NULL;
1856   }
1857 
1858   // Deallocate JNI identifiers for jfieldIDs
1859   JNIid::deallocate(jni_ids());
1860   set_jni_ids(NULL);
1861 
1862   jmethodID* jmeths = methods_jmethod_ids_acquire();
1863   if (jmeths != (jmethodID*)NULL) {
1864     release_set_methods_jmethod_ids(NULL);
1865     FreeHeap(jmeths);
1866   }
1867 
1868   int* indices = methods_cached_itable_indices_acquire();
1869   if (indices != (int*)NULL) {
1870     release_set_methods_cached_itable_indices(NULL);
1871     FreeHeap(indices);
1872   }
1873 
1874   // release dependencies
1875   nmethodBucket* b = _dependencies;
1876   _dependencies = NULL;
1877   while (b != NULL) {
1878     nmethodBucket* next = b->next();
1879     delete b;
1880     b = next;
1881   }
1882 
1883   // Deallocate breakpoint records
1884   if (breakpoints() != 0x0) {
1885     methods_do(clear_all_breakpoints);
1886     assert(breakpoints() == 0x0, "should have cleared breakpoints");
1887   }
1888 
1889   // deallocate information about previous versions
1890   if (_previous_versions != NULL) {
1891     for (int i = _previous_versions->length() - 1; i >= 0; i--) {
1892       PreviousVersionNode * pv_node = _previous_versions->at(i);
1893       delete pv_node;
1894     }
1895     delete _previous_versions;
1896     _previous_versions = NULL;
1897   }
1898 
1899   // deallocate the cached class file
1900   if (_cached_class_file_bytes != NULL) {
1901     os::free(_cached_class_file_bytes);
1902     _cached_class_file_bytes = NULL;
1903     _cached_class_file_len = 0;
1904   }
1905 
1906   // Decrement symbol reference counts associated with the unloaded class.
1907   if (_name != NULL) _name->decrement_refcount();
1908   // unreference array name derived from this class name (arrays of an unloaded
1909   // class can't be referenced anymore).
1910   if (_array_name != NULL)  _array_name->decrement_refcount();
1911   if (_source_file_name != NULL) _source_file_name->decrement_refcount();
1912   if (_source_debug_extension != NULL) _source_debug_extension->decrement_refcount();
1913   // walk constant pool and decrement symbol reference counts
1914   _constants->unreference_symbols();
1915 }
1916 
1917 void instanceKlass::set_source_file_name(Symbol* n) {
1918   _source_file_name = n;
1919   if (_source_file_name != NULL) _source_file_name->increment_refcount();
1920 }
1921 
1922 void instanceKlass::set_source_debug_extension(Symbol* n) {
1923   _source_debug_extension = n;
1924   if (_source_debug_extension != NULL) _source_debug_extension->increment_refcount();
1925 }
1926 
1927 address instanceKlass::static_field_addr(int offset) {
1928   return (address)(offset + instanceMirrorKlass::offset_of_static_fields() + (intptr_t)java_mirror());
1929 }
1930 
1931 
1932 const char* instanceKlass::signature_name() const {
1933   const char* src = (const char*) (name()->as_C_string());
1934   const int src_length = (int)strlen(src);
1935   char* dest = NEW_RESOURCE_ARRAY(char, src_length + 3);
1936   int src_index = 0;
1937   int dest_index = 0;
1938   dest[dest_index++] = 'L';
1939   while (src_index < src_length) {
1940     dest[dest_index++] = src[src_index++];
1941   }
1942   dest[dest_index++] = ';';
1943   dest[dest_index] = '\0';
1944   return dest;
1945 }
1946 
1947 // different verisons of is_same_class_package
1948 bool instanceKlass::is_same_class_package(klassOop class2) {
1949   klassOop class1 = as_klassOop();
1950   oop classloader1 = instanceKlass::cast(class1)->class_loader();
1951   Symbol* classname1 = Klass::cast(class1)->name();
1952 
1953   if (Klass::cast(class2)->oop_is_objArray()) {
1954     class2 = objArrayKlass::cast(class2)->bottom_klass();
1955   }
1956   oop classloader2;
1957   if (Klass::cast(class2)->oop_is_instance()) {
1958     classloader2 = instanceKlass::cast(class2)->class_loader();
1959   } else {
1960     assert(Klass::cast(class2)->oop_is_typeArray(), "should be type array");
1961     classloader2 = NULL;
1962   }
1963   Symbol* classname2 = Klass::cast(class2)->name();
1964 
1965   return instanceKlass::is_same_class_package(classloader1, classname1,
1966                                               classloader2, classname2);
1967 }
1968 
1969 bool instanceKlass::is_same_class_package(oop classloader2, Symbol* classname2) {
1970   klassOop class1 = as_klassOop();
1971   oop classloader1 = instanceKlass::cast(class1)->class_loader();
1972   Symbol* classname1 = Klass::cast(class1)->name();
1973 
1974   return instanceKlass::is_same_class_package(classloader1, classname1,
1975                                               classloader2, classname2);
1976 }
1977 
1978 // return true if two classes are in the same package, classloader
1979 // and classname information is enough to determine a class's package
1980 bool instanceKlass::is_same_class_package(oop class_loader1, Symbol* class_name1,
1981                                           oop class_loader2, Symbol* class_name2) {
1982   if (class_loader1 != class_loader2) {
1983     return false;
1984   } else if (class_name1 == class_name2) {
1985     return true;                // skip painful bytewise comparison
1986   } else {
1987     ResourceMark rm;
1988 
1989     // The Symbol*'s are in UTF8 encoding. Since we only need to check explicitly
1990     // for ASCII characters ('/', 'L', '['), we can keep them in UTF8 encoding.
1991     // Otherwise, we just compare jbyte values between the strings.
1992     const jbyte *name1 = class_name1->base();
1993     const jbyte *name2 = class_name2->base();
1994 
1995     const jbyte *last_slash1 = UTF8::strrchr(name1, class_name1->utf8_length(), '/');
1996     const jbyte *last_slash2 = UTF8::strrchr(name2, class_name2->utf8_length(), '/');
1997 
1998     if ((last_slash1 == NULL) || (last_slash2 == NULL)) {
1999       // One of the two doesn't have a package.  Only return true
2000       // if the other one also doesn't have a package.
2001       return last_slash1 == last_slash2;
2002     } else {
2003       // Skip over '['s
2004       if (*name1 == '[') {
2005         do {
2006           name1++;
2007         } while (*name1 == '[');
2008         if (*name1 != 'L') {
2009           // Something is terribly wrong.  Shouldn't be here.
2010           return false;
2011         }
2012       }
2013       if (*name2 == '[') {
2014         do {
2015           name2++;
2016         } while (*name2 == '[');
2017         if (*name2 != 'L') {
2018           // Something is terribly wrong.  Shouldn't be here.
2019           return false;
2020         }
2021       }
2022 
2023       // Check that package part is identical
2024       int length1 = last_slash1 - name1;
2025       int length2 = last_slash2 - name2;
2026 
2027       return UTF8::equal(name1, length1, name2, length2);
2028     }
2029   }
2030 }
2031 
2032 // Returns true iff super_method can be overridden by a method in targetclassname
2033 // See JSL 3rd edition 8.4.6.1
2034 // Assumes name-signature match
2035 // "this" is instanceKlass of super_method which must exist
2036 // note that the instanceKlass of the method in the targetclassname has not always been created yet
2037 bool instanceKlass::is_override(methodHandle super_method, Handle targetclassloader, Symbol* targetclassname, TRAPS) {
2038    // Private methods can not be overridden
2039    if (super_method->is_private()) {
2040      return false;
2041    }
2042    // If super method is accessible, then override
2043    if ((super_method->is_protected()) ||
2044        (super_method->is_public())) {
2045      return true;
2046    }
2047    // Package-private methods are not inherited outside of package
2048    assert(super_method->is_package_private(), "must be package private");
2049    return(is_same_class_package(targetclassloader(), targetclassname));
2050 }
2051 
2052 /* defined for now in jvm.cpp, for historical reasons *--
2053 klassOop instanceKlass::compute_enclosing_class_impl(instanceKlassHandle self,
2054                                                      Symbol*& simple_name_result, TRAPS) {
2055   ...
2056 }
2057 */
2058 
2059 // tell if two classes have the same enclosing class (at package level)
2060 bool instanceKlass::is_same_package_member_impl(instanceKlassHandle class1,
2061                                                 klassOop class2_oop, TRAPS) {
2062   if (class2_oop == class1->as_klassOop())          return true;
2063   if (!Klass::cast(class2_oop)->oop_is_instance())  return false;
2064   instanceKlassHandle class2(THREAD, class2_oop);
2065 
2066   // must be in same package before we try anything else
2067   if (!class1->is_same_class_package(class2->class_loader(), class2->name()))
2068     return false;
2069 
2070   // As long as there is an outer1.getEnclosingClass,
2071   // shift the search outward.
2072   instanceKlassHandle outer1 = class1;
2073   for (;;) {
2074     // As we walk along, look for equalities between outer1 and class2.
2075     // Eventually, the walks will terminate as outer1 stops
2076     // at the top-level class around the original class.
2077     bool ignore_inner_is_member;
2078     klassOop next = outer1->compute_enclosing_class(&ignore_inner_is_member,
2079                                                     CHECK_false);
2080     if (next == NULL)  break;
2081     if (next == class2())  return true;
2082     outer1 = instanceKlassHandle(THREAD, next);
2083   }
2084 
2085   // Now do the same for class2.
2086   instanceKlassHandle outer2 = class2;
2087   for (;;) {
2088     bool ignore_inner_is_member;
2089     klassOop next = outer2->compute_enclosing_class(&ignore_inner_is_member,
2090                                                     CHECK_false);
2091     if (next == NULL)  break;
2092     // Might as well check the new outer against all available values.
2093     if (next == class1())  return true;
2094     if (next == outer1())  return true;
2095     outer2 = instanceKlassHandle(THREAD, next);
2096   }
2097 
2098   // If by this point we have not found an equality between the
2099   // two classes, we know they are in separate package members.
2100   return false;
2101 }
2102 
2103 
2104 jint instanceKlass::compute_modifier_flags(TRAPS) const {
2105   klassOop k = as_klassOop();
2106   jint access = access_flags().as_int();
2107 
2108   // But check if it happens to be member class.
2109   typeArrayOop inner_class_list = inner_classes();
2110   int length = (inner_class_list == NULL) ? 0 : inner_class_list->length();
2111   assert (length % instanceKlass::inner_class_next_offset == 0, "just checking");
2112   if (length > 0) {
2113     typeArrayHandle inner_class_list_h(THREAD, inner_class_list);
2114     instanceKlassHandle ik(THREAD, k);
2115     for (int i = 0; i < length; i += instanceKlass::inner_class_next_offset) {
2116       int ioff = inner_class_list_h->ushort_at(
2117                       i + instanceKlass::inner_class_inner_class_info_offset);
2118 
2119       // Inner class attribute can be zero, skip it.
2120       // Strange but true:  JVM spec. allows null inner class refs.
2121       if (ioff == 0) continue;
2122 
2123       // only look at classes that are already loaded
2124       // since we are looking for the flags for our self.
2125       Symbol* inner_name = ik->constants()->klass_name_at(ioff);
2126       if ((ik->name() == inner_name)) {
2127         // This is really a member class.
2128         access = inner_class_list_h->ushort_at(i + instanceKlass::inner_class_access_flags_offset);
2129         break;
2130       }
2131     }
2132   }
2133   // Remember to strip ACC_SUPER bit
2134   return (access & (~JVM_ACC_SUPER)) & JVM_ACC_WRITTEN_FLAGS;
2135 }
2136 
2137 jint instanceKlass::jvmti_class_status() const {
2138   jint result = 0;
2139 
2140   if (is_linked()) {
2141     result |= JVMTI_CLASS_STATUS_VERIFIED | JVMTI_CLASS_STATUS_PREPARED;
2142   }
2143 
2144   if (is_initialized()) {
2145     assert(is_linked(), "Class status is not consistent");
2146     result |= JVMTI_CLASS_STATUS_INITIALIZED;
2147   }
2148   if (is_in_error_state()) {
2149     result |= JVMTI_CLASS_STATUS_ERROR;
2150   }
2151   return result;
2152 }
2153 
2154 methodOop instanceKlass::method_at_itable(klassOop holder, int index, TRAPS) {
2155   itableOffsetEntry* ioe = (itableOffsetEntry*)start_of_itable();
2156   int method_table_offset_in_words = ioe->offset()/wordSize;
2157   int nof_interfaces = (method_table_offset_in_words - itable_offset_in_words())
2158                        / itableOffsetEntry::size();
2159 
2160   for (int cnt = 0 ; ; cnt ++, ioe ++) {
2161     // If the interface isn't implemented by the receiver class,
2162     // the VM should throw IncompatibleClassChangeError.
2163     if (cnt >= nof_interfaces) {
2164       THROW_0(vmSymbols::java_lang_IncompatibleClassChangeError());
2165     }
2166 
2167     klassOop ik = ioe->interface_klass();
2168     if (ik == holder) break;
2169   }
2170 
2171   itableMethodEntry* ime = ioe->first_method_entry(as_klassOop());
2172   methodOop m = ime[index].method();
2173   if (m == NULL) {
2174     THROW_0(vmSymbols::java_lang_AbstractMethodError());
2175   }
2176   return m;
2177 }
2178 
2179 // On-stack replacement stuff
2180 void instanceKlass::add_osr_nmethod(nmethod* n) {
2181   // only one compilation can be active
2182   NEEDS_CLEANUP
2183   // This is a short non-blocking critical region, so the no safepoint check is ok.
2184   OsrList_lock->lock_without_safepoint_check();
2185   assert(n->is_osr_method(), "wrong kind of nmethod");
2186   n->set_osr_link(osr_nmethods_head());
2187   set_osr_nmethods_head(n);
2188   // Raise the highest osr level if necessary
2189   if (TieredCompilation) {
2190     methodOop m = n->method();
2191     m->set_highest_osr_comp_level(MAX2(m->highest_osr_comp_level(), n->comp_level()));
2192   }
2193   // Remember to unlock again
2194   OsrList_lock->unlock();
2195 
2196   // Get rid of the osr methods for the same bci that have lower levels.
2197   if (TieredCompilation) {
2198     for (int l = CompLevel_limited_profile; l < n->comp_level(); l++) {
2199       nmethod *inv = lookup_osr_nmethod(n->method(), n->osr_entry_bci(), l, true);
2200       if (inv != NULL && inv->is_in_use()) {
2201         inv->make_not_entrant();
2202       }
2203     }
2204   }
2205 }
2206 
2207 
2208 void instanceKlass::remove_osr_nmethod(nmethod* n) {
2209   // This is a short non-blocking critical region, so the no safepoint check is ok.
2210   OsrList_lock->lock_without_safepoint_check();
2211   assert(n->is_osr_method(), "wrong kind of nmethod");
2212   nmethod* last = NULL;
2213   nmethod* cur  = osr_nmethods_head();
2214   int max_level = CompLevel_none;  // Find the max comp level excluding n
2215   methodOop m = n->method();
2216   // Search for match
2217   while(cur != NULL && cur != n) {
2218     if (TieredCompilation) {
2219       // Find max level before n
2220       max_level = MAX2(max_level, cur->comp_level());
2221     }
2222     last = cur;
2223     cur = cur->osr_link();
2224   }
2225   nmethod* next = NULL;
2226   if (cur == n) {
2227     next = cur->osr_link();
2228     if (last == NULL) {
2229       // Remove first element
2230       set_osr_nmethods_head(next);
2231     } else {
2232       last->set_osr_link(next);
2233     }
2234   }
2235   n->set_osr_link(NULL);
2236   if (TieredCompilation) {
2237     cur = next;
2238     while (cur != NULL) {
2239       // Find max level after n
2240       max_level = MAX2(max_level, cur->comp_level());
2241       cur = cur->osr_link();
2242     }
2243     m->set_highest_osr_comp_level(max_level);
2244   }
2245   // Remember to unlock again
2246   OsrList_lock->unlock();
2247 }
2248 
2249 nmethod* instanceKlass::lookup_osr_nmethod(const methodOop m, int bci, int comp_level, bool match_level) const {
2250   // This is a short non-blocking critical region, so the no safepoint check is ok.
2251   OsrList_lock->lock_without_safepoint_check();
2252   nmethod* osr = osr_nmethods_head();
2253   nmethod* best = NULL;
2254   while (osr != NULL) {
2255     assert(osr->is_osr_method(), "wrong kind of nmethod found in chain");
2256     // There can be a time when a c1 osr method exists but we are waiting
2257     // for a c2 version. When c2 completes its osr nmethod we will trash
2258     // the c1 version and only be able to find the c2 version. However
2259     // while we overflow in the c1 code at back branches we don't want to
2260     // try and switch to the same code as we are already running
2261 
2262     if (osr->method() == m &&
2263         (bci == InvocationEntryBci || osr->osr_entry_bci() == bci)) {
2264       if (match_level) {
2265         if (osr->comp_level() == comp_level) {
2266           // Found a match - return it.
2267           OsrList_lock->unlock();
2268           return osr;
2269         }
2270       } else {
2271         if (best == NULL || (osr->comp_level() > best->comp_level())) {
2272           if (osr->comp_level() == CompLevel_highest_tier) {
2273             // Found the best possible - return it.
2274             OsrList_lock->unlock();
2275             return osr;
2276           }
2277           best = osr;
2278         }
2279       }
2280     }
2281     osr = osr->osr_link();
2282   }
2283   OsrList_lock->unlock();
2284   if (best != NULL && best->comp_level() >= comp_level && match_level == false) {
2285     return best;
2286   }
2287   return NULL;
2288 }
2289 
2290 // -----------------------------------------------------------------------------------------------------
2291 #ifndef PRODUCT
2292 
2293 // Printing
2294 
2295 #define BULLET  " - "
2296 
2297 void FieldPrinter::do_field(fieldDescriptor* fd) {
2298   _st->print(BULLET);
2299    if (_obj == NULL) {
2300      fd->print_on(_st);
2301      _st->cr();
2302    } else {
2303      fd->print_on_for(_st, _obj);
2304      _st->cr();
2305    }
2306 }
2307 
2308 
2309 void instanceKlass::oop_print_on(oop obj, outputStream* st) {
2310   Klass::oop_print_on(obj, st);
2311 
2312   if (as_klassOop() == SystemDictionary::String_klass()) {
2313     typeArrayOop value  = java_lang_String::value(obj);
2314     juint        offset = java_lang_String::offset(obj);
2315     juint        length = java_lang_String::length(obj);
2316     if (value != NULL &&
2317         value->is_typeArray() &&
2318         offset          <= (juint) value->length() &&
2319         offset + length <= (juint) value->length()) {
2320       st->print(BULLET"string: ");
2321       Handle h_obj(obj);
2322       java_lang_String::print(h_obj, st);
2323       st->cr();
2324       if (!WizardMode)  return;  // that is enough
2325     }
2326   }
2327 
2328   st->print_cr(BULLET"---- fields (total size %d words):", oop_size(obj));
2329   FieldPrinter print_field(st, obj);
2330   do_nonstatic_fields(&print_field);
2331 
2332   if (as_klassOop() == SystemDictionary::Class_klass()) {
2333     st->print(BULLET"signature: ");
2334     java_lang_Class::print_signature(obj, st);
2335     st->cr();
2336     klassOop mirrored_klass = java_lang_Class::as_klassOop(obj);
2337     st->print(BULLET"fake entry for mirror: ");
2338     mirrored_klass->print_value_on(st);
2339     st->cr();
2340     st->print(BULLET"fake entry resolved_constructor: ");
2341     methodOop ctor = java_lang_Class::resolved_constructor(obj);
2342     ctor->print_value_on(st);
2343     klassOop array_klass = java_lang_Class::array_klass(obj);
2344     st->cr();
2345     st->print(BULLET"fake entry for array: ");
2346     array_klass->print_value_on(st);
2347     st->cr();
2348     st->print_cr(BULLET"fake entry for oop_size: %d", java_lang_Class::oop_size(obj));
2349     st->print_cr(BULLET"fake entry for static_oop_field_count: %d", java_lang_Class::static_oop_field_count(obj));
2350     klassOop real_klass = java_lang_Class::as_klassOop(obj);
2351     if (real_klass != NULL && real_klass->klass_part()->oop_is_instance()) {
2352       instanceKlass::cast(real_klass)->do_local_static_fields(&print_field);
2353     }
2354   } else if (as_klassOop() == SystemDictionary::MethodType_klass()) {
2355     st->print(BULLET"signature: ");
2356     java_lang_invoke_MethodType::print_signature(obj, st);
2357     st->cr();
2358   }
2359 }
2360 
2361 #endif //PRODUCT
2362 
2363 void instanceKlass::oop_print_value_on(oop obj, outputStream* st) {
2364   st->print("a ");
2365   name()->print_value_on(st);
2366   obj->print_address_on(st);
2367   if (as_klassOop() == SystemDictionary::String_klass()
2368       && java_lang_String::value(obj) != NULL) {
2369     ResourceMark rm;
2370     int len = java_lang_String::length(obj);
2371     int plen = (len < 24 ? len : 12);
2372     char* str = java_lang_String::as_utf8_string(obj, 0, plen);
2373     st->print(" = \"%s\"", str);
2374     if (len > plen)
2375       st->print("...[%d]", len);
2376   } else if (as_klassOop() == SystemDictionary::Class_klass()) {
2377     klassOop k = java_lang_Class::as_klassOop(obj);
2378     st->print(" = ");
2379     if (k != NULL) {
2380       k->print_value_on(st);
2381     } else {
2382       const char* tname = type2name(java_lang_Class::primitive_type(obj));
2383       st->print("%s", tname ? tname : "type?");
2384     }
2385   } else if (as_klassOop() == SystemDictionary::MethodType_klass()) {
2386     st->print(" = ");
2387     java_lang_invoke_MethodType::print_signature(obj, st);
2388   } else if (java_lang_boxing_object::is_instance(obj)) {
2389     st->print(" = ");
2390     java_lang_boxing_object::print(obj, st);
2391   }
2392 }
2393 
2394 const char* instanceKlass::internal_name() const {
2395   return external_name();
2396 }
2397 
2398 // Verification
2399 
2400 class VerifyFieldClosure: public OopClosure {
2401  protected:
2402   template <class T> void do_oop_work(T* p) {
2403     guarantee(Universe::heap()->is_in_closed_subset(p), "should be in heap");
2404     oop obj = oopDesc::load_decode_heap_oop(p);
2405     if (!obj->is_oop_or_null()) {
2406       tty->print_cr("Failed: " PTR_FORMAT " -> " PTR_FORMAT, p, (address)obj);
2407       Universe::print();
2408       guarantee(false, "boom");
2409     }
2410   }
2411  public:
2412   virtual void do_oop(oop* p)       { VerifyFieldClosure::do_oop_work(p); }
2413   virtual void do_oop(narrowOop* p) { VerifyFieldClosure::do_oop_work(p); }
2414 };
2415 
2416 void instanceKlass::oop_verify_on(oop obj, outputStream* st) {
2417   Klass::oop_verify_on(obj, st);
2418   VerifyFieldClosure blk;
2419   oop_oop_iterate(obj, &blk);
2420 }
2421 
2422 // JNIid class for jfieldIDs only
2423 // Note to reviewers:
2424 // These JNI functions are just moved over to column 1 and not changed
2425 // in the compressed oops workspace.
2426 JNIid::JNIid(klassOop holder, int offset, JNIid* next) {
2427   _holder = holder;
2428   _offset = offset;
2429   _next = next;
2430   debug_only(_is_static_field_id = false;)
2431 }
2432 
2433 
2434 JNIid* JNIid::find(int offset) {
2435   JNIid* current = this;
2436   while (current != NULL) {
2437     if (current->offset() == offset) return current;
2438     current = current->next();
2439   }
2440   return NULL;
2441 }
2442 
2443 void JNIid::oops_do(OopClosure* f) {
2444   for (JNIid* cur = this; cur != NULL; cur = cur->next()) {
2445     f->do_oop(cur->holder_addr());
2446   }
2447 }
2448 
2449 void JNIid::deallocate(JNIid* current) {
2450   while (current != NULL) {
2451     JNIid* next = current->next();
2452     delete current;
2453     current = next;
2454   }
2455 }
2456 
2457 
2458 void JNIid::verify(klassOop holder) {
2459   int first_field_offset  = instanceMirrorKlass::offset_of_static_fields();
2460   int end_field_offset;
2461   end_field_offset = first_field_offset + (instanceKlass::cast(holder)->static_field_size() * wordSize);
2462 
2463   JNIid* current = this;
2464   while (current != NULL) {
2465     guarantee(current->holder() == holder, "Invalid klass in JNIid");
2466 #ifdef ASSERT
2467     int o = current->offset();
2468     if (current->is_static_field_id()) {
2469       guarantee(o >= first_field_offset  && o < end_field_offset,  "Invalid static field offset in JNIid");
2470     }
2471 #endif
2472     current = current->next();
2473   }
2474 }
2475 
2476 
2477 #ifdef ASSERT
2478 void instanceKlass::set_init_state(ClassState state) {
2479   bool good_state = as_klassOop()->is_shared() ? (_init_state <= state)
2480                                                : (_init_state < state);
2481   assert(good_state || state == allocated, "illegal state transition");
2482   _init_state = (u1)state;
2483 }
2484 #endif
2485 
2486 
2487 // RedefineClasses() support for previous versions:
2488 
2489 // Add an information node that contains weak references to the
2490 // interesting parts of the previous version of the_class.
2491 // This is also where we clean out any unused weak references.
2492 // Note that while we delete nodes from the _previous_versions
2493 // array, we never delete the array itself until the klass is
2494 // unloaded. The has_been_redefined() query depends on that fact.
2495 //
2496 void instanceKlass::add_previous_version(instanceKlassHandle ikh,
2497        BitMap* emcp_methods, int emcp_method_count) {
2498   assert(Thread::current()->is_VM_thread(),
2499          "only VMThread can add previous versions");
2500 
2501   if (_previous_versions == NULL) {
2502     // This is the first previous version so make some space.
2503     // Start with 2 elements under the assumption that the class
2504     // won't be redefined much.
2505     _previous_versions =  new (ResourceObj::C_HEAP)
2506                             GrowableArray<PreviousVersionNode *>(2, true);
2507   }
2508 
2509   // RC_TRACE macro has an embedded ResourceMark
2510   RC_TRACE(0x00000100, ("adding previous version ref for %s @%d, EMCP_cnt=%d",
2511     ikh->external_name(), _previous_versions->length(), emcp_method_count));
2512   constantPoolHandle cp_h(ikh->constants());
2513   jobject cp_ref;
2514   if (cp_h->is_shared()) {
2515     // a shared ConstantPool requires a regular reference; a weak
2516     // reference would be collectible
2517     cp_ref = JNIHandles::make_global(cp_h);
2518   } else {
2519     cp_ref = JNIHandles::make_weak_global(cp_h);
2520   }
2521   PreviousVersionNode * pv_node = NULL;
2522   objArrayOop old_methods = ikh->methods();
2523 
2524   if (emcp_method_count == 0) {
2525     // non-shared ConstantPool gets a weak reference
2526     pv_node = new PreviousVersionNode(cp_ref, !cp_h->is_shared(), NULL);
2527     RC_TRACE(0x00000400,
2528       ("add: all methods are obsolete; flushing any EMCP weak refs"));
2529   } else {
2530     int local_count = 0;
2531     GrowableArray<jweak>* method_refs = new (ResourceObj::C_HEAP)
2532       GrowableArray<jweak>(emcp_method_count, true);
2533     for (int i = 0; i < old_methods->length(); i++) {
2534       if (emcp_methods->at(i)) {
2535         // this old method is EMCP so save a weak ref
2536         methodOop old_method = (methodOop) old_methods->obj_at(i);
2537         methodHandle old_method_h(old_method);
2538         jweak method_ref = JNIHandles::make_weak_global(old_method_h);
2539         method_refs->append(method_ref);
2540         if (++local_count >= emcp_method_count) {
2541           // no more EMCP methods so bail out now
2542           break;
2543         }
2544       }
2545     }
2546     // non-shared ConstantPool gets a weak reference
2547     pv_node = new PreviousVersionNode(cp_ref, !cp_h->is_shared(), method_refs);
2548   }
2549 
2550   _previous_versions->append(pv_node);
2551 
2552   // Using weak references allows the interesting parts of previous
2553   // classes to be GC'ed when they are no longer needed. Since the
2554   // caller is the VMThread and we are at a safepoint, this is a good
2555   // time to clear out unused weak references.
2556 
2557   RC_TRACE(0x00000400, ("add: previous version length=%d",
2558     _previous_versions->length()));
2559 
2560   // skip the last entry since we just added it
2561   for (int i = _previous_versions->length() - 2; i >= 0; i--) {
2562     // check the previous versions array for a GC'ed weak refs
2563     pv_node = _previous_versions->at(i);
2564     cp_ref = pv_node->prev_constant_pool();
2565     assert(cp_ref != NULL, "cp ref was unexpectedly cleared");
2566     if (cp_ref == NULL) {
2567       delete pv_node;
2568       _previous_versions->remove_at(i);
2569       // Since we are traversing the array backwards, we don't have to
2570       // do anything special with the index.
2571       continue;  // robustness
2572     }
2573 
2574     constantPoolOop cp = (constantPoolOop)JNIHandles::resolve(cp_ref);
2575     if (cp == NULL) {
2576       // this entry has been GC'ed so remove it
2577       delete pv_node;
2578       _previous_versions->remove_at(i);
2579       // Since we are traversing the array backwards, we don't have to
2580       // do anything special with the index.
2581       continue;
2582     } else {
2583       RC_TRACE(0x00000400, ("add: previous version @%d is alive", i));
2584     }
2585 
2586     GrowableArray<jweak>* method_refs = pv_node->prev_EMCP_methods();
2587     if (method_refs != NULL) {
2588       RC_TRACE(0x00000400, ("add: previous methods length=%d",
2589         method_refs->length()));
2590       for (int j = method_refs->length() - 1; j >= 0; j--) {
2591         jweak method_ref = method_refs->at(j);
2592         assert(method_ref != NULL, "weak method ref was unexpectedly cleared");
2593         if (method_ref == NULL) {
2594           method_refs->remove_at(j);
2595           // Since we are traversing the array backwards, we don't have to
2596           // do anything special with the index.
2597           continue;  // robustness
2598         }
2599 
2600         methodOop method = (methodOop)JNIHandles::resolve(method_ref);
2601         if (method == NULL || emcp_method_count == 0) {
2602           // This method entry has been GC'ed or the current
2603           // RedefineClasses() call has made all methods obsolete
2604           // so remove it.
2605           JNIHandles::destroy_weak_global(method_ref);
2606           method_refs->remove_at(j);
2607         } else {
2608           // RC_TRACE macro has an embedded ResourceMark
2609           RC_TRACE(0x00000400,
2610             ("add: %s(%s): previous method @%d in version @%d is alive",
2611             method->name()->as_C_string(), method->signature()->as_C_string(),
2612             j, i));
2613         }
2614       }
2615     }
2616   }
2617 
2618   int obsolete_method_count = old_methods->length() - emcp_method_count;
2619 
2620   if (emcp_method_count != 0 && obsolete_method_count != 0 &&
2621       _previous_versions->length() > 1) {
2622     // We have a mix of obsolete and EMCP methods. If there is more
2623     // than the previous version that we just added, then we have to
2624     // clear out any matching EMCP method entries the hard way.
2625     int local_count = 0;
2626     for (int i = 0; i < old_methods->length(); i++) {
2627       if (!emcp_methods->at(i)) {
2628         // only obsolete methods are interesting
2629         methodOop old_method = (methodOop) old_methods->obj_at(i);
2630         Symbol* m_name = old_method->name();
2631         Symbol* m_signature = old_method->signature();
2632 
2633         // skip the last entry since we just added it
2634         for (int j = _previous_versions->length() - 2; j >= 0; j--) {
2635           // check the previous versions array for a GC'ed weak refs
2636           pv_node = _previous_versions->at(j);
2637           cp_ref = pv_node->prev_constant_pool();
2638           assert(cp_ref != NULL, "cp ref was unexpectedly cleared");
2639           if (cp_ref == NULL) {
2640             delete pv_node;
2641             _previous_versions->remove_at(j);
2642             // Since we are traversing the array backwards, we don't have to
2643             // do anything special with the index.
2644             continue;  // robustness
2645           }
2646 
2647           constantPoolOop cp = (constantPoolOop)JNIHandles::resolve(cp_ref);
2648           if (cp == NULL) {
2649             // this entry has been GC'ed so remove it
2650             delete pv_node;
2651             _previous_versions->remove_at(j);
2652             // Since we are traversing the array backwards, we don't have to
2653             // do anything special with the index.
2654             continue;
2655           }
2656 
2657           GrowableArray<jweak>* method_refs = pv_node->prev_EMCP_methods();
2658           if (method_refs == NULL) {
2659             // We have run into a PreviousVersion generation where
2660             // all methods were made obsolete during that generation's
2661             // RedefineClasses() operation. At the time of that
2662             // operation, all EMCP methods were flushed so we don't
2663             // have to go back any further.
2664             //
2665             // A NULL method_refs is different than an empty method_refs.
2666             // We cannot infer any optimizations about older generations
2667             // from an empty method_refs for the current generation.
2668             break;
2669           }
2670 
2671           for (int k = method_refs->length() - 1; k >= 0; k--) {
2672             jweak method_ref = method_refs->at(k);
2673             assert(method_ref != NULL,
2674               "weak method ref was unexpectedly cleared");
2675             if (method_ref == NULL) {
2676               method_refs->remove_at(k);
2677               // Since we are traversing the array backwards, we don't
2678               // have to do anything special with the index.
2679               continue;  // robustness
2680             }
2681 
2682             methodOop method = (methodOop)JNIHandles::resolve(method_ref);
2683             if (method == NULL) {
2684               // this method entry has been GC'ed so skip it
2685               JNIHandles::destroy_weak_global(method_ref);
2686               method_refs->remove_at(k);
2687               continue;
2688             }
2689 
2690             if (method->name() == m_name &&
2691                 method->signature() == m_signature) {
2692               // The current RedefineClasses() call has made all EMCP
2693               // versions of this method obsolete so mark it as obsolete
2694               // and remove the weak ref.
2695               RC_TRACE(0x00000400,
2696                 ("add: %s(%s): flush obsolete method @%d in version @%d",
2697                 m_name->as_C_string(), m_signature->as_C_string(), k, j));
2698 
2699               method->set_is_obsolete();
2700               JNIHandles::destroy_weak_global(method_ref);
2701               method_refs->remove_at(k);
2702               break;
2703             }
2704           }
2705 
2706           // The previous loop may not find a matching EMCP method, but
2707           // that doesn't mean that we can optimize and not go any
2708           // further back in the PreviousVersion generations. The EMCP
2709           // method for this generation could have already been GC'ed,
2710           // but there still may be an older EMCP method that has not
2711           // been GC'ed.
2712         }
2713 
2714         if (++local_count >= obsolete_method_count) {
2715           // no more obsolete methods so bail out now
2716           break;
2717         }
2718       }
2719     }
2720   }
2721 } // end add_previous_version()
2722 
2723 
2724 // Determine if instanceKlass has a previous version.
2725 bool instanceKlass::has_previous_version() const {
2726   if (_previous_versions == NULL) {
2727     // no previous versions array so answer is easy
2728     return false;
2729   }
2730 
2731   for (int i = _previous_versions->length() - 1; i >= 0; i--) {
2732     // Check the previous versions array for an info node that hasn't
2733     // been GC'ed
2734     PreviousVersionNode * pv_node = _previous_versions->at(i);
2735 
2736     jobject cp_ref = pv_node->prev_constant_pool();
2737     assert(cp_ref != NULL, "cp reference was unexpectedly cleared");
2738     if (cp_ref == NULL) {
2739       continue;  // robustness
2740     }
2741 
2742     constantPoolOop cp = (constantPoolOop)JNIHandles::resolve(cp_ref);
2743     if (cp != NULL) {
2744       // we have at least one previous version
2745       return true;
2746     }
2747 
2748     // We don't have to check the method refs. If the constant pool has
2749     // been GC'ed then so have the methods.
2750   }
2751 
2752   // all of the underlying nodes' info has been GC'ed
2753   return false;
2754 } // end has_previous_version()
2755 
2756 methodOop instanceKlass::method_with_idnum(int idnum) {
2757   methodOop m = NULL;
2758   if (idnum < methods()->length()) {
2759     m = (methodOop) methods()->obj_at(idnum);
2760   }
2761   if (m == NULL || m->method_idnum() != idnum) {
2762     for (int index = 0; index < methods()->length(); ++index) {
2763       m = (methodOop) methods()->obj_at(index);
2764       if (m->method_idnum() == idnum) {
2765         return m;
2766       }
2767     }
2768   }
2769   return m;
2770 }
2771 
2772 
2773 // Set the annotation at 'idnum' to 'anno'.
2774 // We don't want to create or extend the array if 'anno' is NULL, since that is the
2775 // default value.  However, if the array exists and is long enough, we must set NULL values.
2776 void instanceKlass::set_methods_annotations_of(int idnum, typeArrayOop anno, objArrayOop* md_p) {
2777   objArrayOop md = *md_p;
2778   if (md != NULL && md->length() > idnum) {
2779     md->obj_at_put(idnum, anno);
2780   } else if (anno != NULL) {
2781     // create the array
2782     int length = MAX2(idnum+1, (int)_idnum_allocated_count);
2783     md = oopFactory::new_system_objArray(length, Thread::current());
2784     if (*md_p != NULL) {
2785       // copy the existing entries
2786       for (int index = 0; index < (*md_p)->length(); index++) {
2787         md->obj_at_put(index, (*md_p)->obj_at(index));
2788       }
2789     }
2790     set_annotations(md, md_p);
2791     md->obj_at_put(idnum, anno);
2792   } // if no array and idnum isn't included there is nothing to do
2793 }
2794 
2795 // Construct a PreviousVersionNode entry for the array hung off
2796 // the instanceKlass.
2797 PreviousVersionNode::PreviousVersionNode(jobject prev_constant_pool,
2798   bool prev_cp_is_weak, GrowableArray<jweak>* prev_EMCP_methods) {
2799 
2800   _prev_constant_pool = prev_constant_pool;
2801   _prev_cp_is_weak = prev_cp_is_weak;
2802   _prev_EMCP_methods = prev_EMCP_methods;
2803 }
2804 
2805 
2806 // Destroy a PreviousVersionNode
2807 PreviousVersionNode::~PreviousVersionNode() {
2808   if (_prev_constant_pool != NULL) {
2809     if (_prev_cp_is_weak) {
2810       JNIHandles::destroy_weak_global(_prev_constant_pool);
2811     } else {
2812       JNIHandles::destroy_global(_prev_constant_pool);
2813     }
2814   }
2815 
2816   if (_prev_EMCP_methods != NULL) {
2817     for (int i = _prev_EMCP_methods->length() - 1; i >= 0; i--) {
2818       jweak method_ref = _prev_EMCP_methods->at(i);
2819       if (method_ref != NULL) {
2820         JNIHandles::destroy_weak_global(method_ref);
2821       }
2822     }
2823     delete _prev_EMCP_methods;
2824   }
2825 }
2826 
2827 
2828 // Construct a PreviousVersionInfo entry
2829 PreviousVersionInfo::PreviousVersionInfo(PreviousVersionNode *pv_node) {
2830   _prev_constant_pool_handle = constantPoolHandle();  // NULL handle
2831   _prev_EMCP_method_handles = NULL;
2832 
2833   jobject cp_ref = pv_node->prev_constant_pool();
2834   assert(cp_ref != NULL, "constant pool ref was unexpectedly cleared");
2835   if (cp_ref == NULL) {
2836     return;  // robustness
2837   }
2838 
2839   constantPoolOop cp = (constantPoolOop)JNIHandles::resolve(cp_ref);
2840   if (cp == NULL) {
2841     // Weak reference has been GC'ed. Since the constant pool has been
2842     // GC'ed, the methods have also been GC'ed.
2843     return;
2844   }
2845 
2846   // make the constantPoolOop safe to return
2847   _prev_constant_pool_handle = constantPoolHandle(cp);
2848 
2849   GrowableArray<jweak>* method_refs = pv_node->prev_EMCP_methods();
2850   if (method_refs == NULL) {
2851     // the instanceKlass did not have any EMCP methods
2852     return;
2853   }
2854 
2855   _prev_EMCP_method_handles = new GrowableArray<methodHandle>(10);
2856 
2857   int n_methods = method_refs->length();
2858   for (int i = 0; i < n_methods; i++) {
2859     jweak method_ref = method_refs->at(i);
2860     assert(method_ref != NULL, "weak method ref was unexpectedly cleared");
2861     if (method_ref == NULL) {
2862       continue;  // robustness
2863     }
2864 
2865     methodOop method = (methodOop)JNIHandles::resolve(method_ref);
2866     if (method == NULL) {
2867       // this entry has been GC'ed so skip it
2868       continue;
2869     }
2870 
2871     // make the methodOop safe to return
2872     _prev_EMCP_method_handles->append(methodHandle(method));
2873   }
2874 }
2875 
2876 
2877 // Destroy a PreviousVersionInfo
2878 PreviousVersionInfo::~PreviousVersionInfo() {
2879   // Since _prev_EMCP_method_handles is not C-heap allocated, we
2880   // don't have to delete it.
2881 }
2882 
2883 
2884 // Construct a helper for walking the previous versions array
2885 PreviousVersionWalker::PreviousVersionWalker(instanceKlass *ik) {
2886   _previous_versions = ik->previous_versions();
2887   _current_index = 0;
2888   // _hm needs no initialization
2889   _current_p = NULL;
2890 }
2891 
2892 
2893 // Destroy a PreviousVersionWalker
2894 PreviousVersionWalker::~PreviousVersionWalker() {
2895   // Delete the current info just in case the caller didn't walk to
2896   // the end of the previous versions list. No harm if _current_p is
2897   // already NULL.
2898   delete _current_p;
2899 
2900   // When _hm is destroyed, all the Handles returned in
2901   // PreviousVersionInfo objects will be destroyed.
2902   // Also, after this destructor is finished it will be
2903   // safe to delete the GrowableArray allocated in the
2904   // PreviousVersionInfo objects.
2905 }
2906 
2907 
2908 // Return the interesting information for the next previous version
2909 // of the klass. Returns NULL if there are no more previous versions.
2910 PreviousVersionInfo* PreviousVersionWalker::next_previous_version() {
2911   if (_previous_versions == NULL) {
2912     // no previous versions so nothing to return
2913     return NULL;
2914   }
2915 
2916   delete _current_p;  // cleanup the previous info for the caller
2917   _current_p = NULL;  // reset to NULL so we don't delete same object twice
2918 
2919   int length = _previous_versions->length();
2920 
2921   while (_current_index < length) {
2922     PreviousVersionNode * pv_node = _previous_versions->at(_current_index++);
2923     PreviousVersionInfo * pv_info = new (ResourceObj::C_HEAP)
2924                                           PreviousVersionInfo(pv_node);
2925 
2926     constantPoolHandle cp_h = pv_info->prev_constant_pool_handle();
2927     if (cp_h.is_null()) {
2928       delete pv_info;
2929 
2930       // The underlying node's info has been GC'ed so try the next one.
2931       // We don't have to check the methods. If the constant pool has
2932       // GC'ed then so have the methods.
2933       continue;
2934     }
2935 
2936     // Found a node with non GC'ed info so return it. The caller will
2937     // need to delete pv_info when they are done with it.
2938     _current_p = pv_info;
2939     return pv_info;
2940   }
2941 
2942   // all of the underlying nodes' info has been GC'ed
2943   return NULL;
2944 } // end next_previous_version()