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 u2 instanceKlass::enclosing_method_data(int offset) {
1136   typeArrayOop inner_class_list = inner_classes();
1137   if (inner_class_list == NULL) {
1138     return 0;
1139   }
1140   int length = inner_class_list->length();
1141   if (length % inner_class_next_offset == 0) {
1142     return 0;
1143   } else {
1144     EXCEPTION_MARK;
1145     int index = length - enclosing_method_attribute_size;
1146     typeArrayHandle inner_class_list_h(THREAD, inner_class_list);
1147     assert(offset < enclosing_method_attribute_size, "invalid offset");
1148     return inner_class_list_h->ushort_at(index + offset);
1149   }
1150 }
1151 
1152 void instanceKlass::set_enclosing_method_indices(u2 class_index,
1153                                                  u2 method_index) {
1154   EXCEPTION_MARK;
1155   typeArrayOop inner_class_list = inner_classes();
1156   assert (inner_class_list != NULL, "_inner_classes list is not set up");
1157   int length = inner_class_list->length();
1158   assert (length % inner_class_next_offset == enclosing_method_attribute_size,
1159           "Incorrect _inner_classes array length");
1160   int index = length - enclosing_method_attribute_size;
1161   typeArrayHandle inner_class_list_h(THREAD, inner_class_list);
1162   inner_class_list_h->ushort_at_put(
1163     index + enclosing_method_class_index_offset, class_index);
1164   inner_class_list_h->ushort_at_put(
1165     index + enclosing_method_method_index_offset, method_index);
1166 }
1167 
1168 // Lookup or create a jmethodID.
1169 // This code is called by the VMThread and JavaThreads so the
1170 // locking has to be done very carefully to avoid deadlocks
1171 // and/or other cache consistency problems.
1172 //
1173 jmethodID instanceKlass::get_jmethod_id(instanceKlassHandle ik_h, methodHandle method_h) {
1174   size_t idnum = (size_t)method_h->method_idnum();
1175   jmethodID* jmeths = ik_h->methods_jmethod_ids_acquire();
1176   size_t length = 0;
1177   jmethodID id = NULL;
1178 
1179   // We use a double-check locking idiom here because this cache is
1180   // performance sensitive. In the normal system, this cache only
1181   // transitions from NULL to non-NULL which is safe because we use
1182   // release_set_methods_jmethod_ids() to advertise the new cache.
1183   // A partially constructed cache should never be seen by a racing
1184   // thread. We also use release_store_ptr() to save a new jmethodID
1185   // in the cache so a partially constructed jmethodID should never be
1186   // seen either. Cache reads of existing jmethodIDs proceed without a
1187   // lock, but cache writes of a new jmethodID requires uniqueness and
1188   // creation of the cache itself requires no leaks so a lock is
1189   // generally acquired in those two cases.
1190   //
1191   // If the RedefineClasses() API has been used, then this cache can
1192   // grow and we'll have transitions from non-NULL to bigger non-NULL.
1193   // Cache creation requires no leaks and we require safety between all
1194   // cache accesses and freeing of the old cache so a lock is generally
1195   // acquired when the RedefineClasses() API has been used.
1196 
1197   if (jmeths != NULL) {
1198     // the cache already exists
1199     if (!ik_h->idnum_can_increment()) {
1200       // the cache can't grow so we can just get the current values
1201       get_jmethod_id_length_value(jmeths, idnum, &length, &id);
1202     } else {
1203       // cache can grow so we have to be more careful
1204       if (Threads::number_of_threads() == 0 ||
1205           SafepointSynchronize::is_at_safepoint()) {
1206         // we're single threaded or at a safepoint - no locking needed
1207         get_jmethod_id_length_value(jmeths, idnum, &length, &id);
1208       } else {
1209         MutexLocker ml(JmethodIdCreation_lock);
1210         get_jmethod_id_length_value(jmeths, idnum, &length, &id);
1211       }
1212     }
1213   }
1214   // implied else:
1215   // we need to allocate a cache so default length and id values are good
1216 
1217   if (jmeths == NULL ||   // no cache yet
1218       length <= idnum ||  // cache is too short
1219       id == NULL) {       // cache doesn't contain entry
1220 
1221     // This function can be called by the VMThread so we have to do all
1222     // things that might block on a safepoint before grabbing the lock.
1223     // Otherwise, we can deadlock with the VMThread or have a cache
1224     // consistency issue. These vars keep track of what we might have
1225     // to free after the lock is dropped.
1226     jmethodID  to_dealloc_id     = NULL;
1227     jmethodID* to_dealloc_jmeths = NULL;
1228 
1229     // may not allocate new_jmeths or use it if we allocate it
1230     jmethodID* new_jmeths = NULL;
1231     if (length <= idnum) {
1232       // allocate a new cache that might be used
1233       size_t size = MAX2(idnum+1, (size_t)ik_h->idnum_allocated_count());
1234       new_jmeths = NEW_C_HEAP_ARRAY(jmethodID, size+1);
1235       memset(new_jmeths, 0, (size+1)*sizeof(jmethodID));
1236       // cache size is stored in element[0], other elements offset by one
1237       new_jmeths[0] = (jmethodID)size;
1238     }
1239 
1240     // allocate a new jmethodID that might be used
1241     jmethodID new_id = NULL;
1242     if (method_h->is_old() && !method_h->is_obsolete()) {
1243       // The method passed in is old (but not obsolete), we need to use the current version
1244       methodOop current_method = ik_h->method_with_idnum((int)idnum);
1245       assert(current_method != NULL, "old and but not obsolete, so should exist");
1246       methodHandle current_method_h(current_method == NULL? method_h() : current_method);
1247       new_id = JNIHandles::make_jmethod_id(current_method_h);
1248     } else {
1249       // It is the current version of the method or an obsolete method,
1250       // use the version passed in
1251       new_id = JNIHandles::make_jmethod_id(method_h);
1252     }
1253 
1254     if (Threads::number_of_threads() == 0 ||
1255         SafepointSynchronize::is_at_safepoint()) {
1256       // we're single threaded or at a safepoint - no locking needed
1257       id = get_jmethod_id_fetch_or_update(ik_h, idnum, new_id, new_jmeths,
1258                                           &to_dealloc_id, &to_dealloc_jmeths);
1259     } else {
1260       MutexLocker ml(JmethodIdCreation_lock);
1261       id = get_jmethod_id_fetch_or_update(ik_h, idnum, new_id, new_jmeths,
1262                                           &to_dealloc_id, &to_dealloc_jmeths);
1263     }
1264 
1265     // The lock has been dropped so we can free resources.
1266     // Free up either the old cache or the new cache if we allocated one.
1267     if (to_dealloc_jmeths != NULL) {
1268       FreeHeap(to_dealloc_jmeths);
1269     }
1270     // free up the new ID since it wasn't needed
1271     if (to_dealloc_id != NULL) {
1272       JNIHandles::destroy_jmethod_id(to_dealloc_id);
1273     }
1274   }
1275   return id;
1276 }
1277 
1278 
1279 // Common code to fetch the jmethodID from the cache or update the
1280 // cache with the new jmethodID. This function should never do anything
1281 // that causes the caller to go to a safepoint or we can deadlock with
1282 // the VMThread or have cache consistency issues.
1283 //
1284 jmethodID instanceKlass::get_jmethod_id_fetch_or_update(
1285             instanceKlassHandle ik_h, size_t idnum, jmethodID new_id,
1286             jmethodID* new_jmeths, jmethodID* to_dealloc_id_p,
1287             jmethodID** to_dealloc_jmeths_p) {
1288   assert(new_id != NULL, "sanity check");
1289   assert(to_dealloc_id_p != NULL, "sanity check");
1290   assert(to_dealloc_jmeths_p != NULL, "sanity check");
1291   assert(Threads::number_of_threads() == 0 ||
1292          SafepointSynchronize::is_at_safepoint() ||
1293          JmethodIdCreation_lock->owned_by_self(), "sanity check");
1294 
1295   // reacquire the cache - we are locked, single threaded or at a safepoint
1296   jmethodID* jmeths = ik_h->methods_jmethod_ids_acquire();
1297   jmethodID  id     = NULL;
1298   size_t     length = 0;
1299 
1300   if (jmeths == NULL ||                         // no cache yet
1301       (length = (size_t)jmeths[0]) <= idnum) {  // cache is too short
1302     if (jmeths != NULL) {
1303       // copy any existing entries from the old cache
1304       for (size_t index = 0; index < length; index++) {
1305         new_jmeths[index+1] = jmeths[index+1];
1306       }
1307       *to_dealloc_jmeths_p = jmeths;  // save old cache for later delete
1308     }
1309     ik_h->release_set_methods_jmethod_ids(jmeths = new_jmeths);
1310   } else {
1311     // fetch jmethodID (if any) from the existing cache
1312     id = jmeths[idnum+1];
1313     *to_dealloc_jmeths_p = new_jmeths;  // save new cache for later delete
1314   }
1315   if (id == NULL) {
1316     // No matching jmethodID in the existing cache or we have a new
1317     // cache or we just grew the cache. This cache write is done here
1318     // by the first thread to win the foot race because a jmethodID
1319     // needs to be unique once it is generally available.
1320     id = new_id;
1321 
1322     // The jmethodID cache can be read while unlocked so we have to
1323     // make sure the new jmethodID is complete before installing it
1324     // in the cache.
1325     OrderAccess::release_store_ptr(&jmeths[idnum+1], id);
1326   } else {
1327     *to_dealloc_id_p = new_id; // save new id for later delete
1328   }
1329   return id;
1330 }
1331 
1332 
1333 // Common code to get the jmethodID cache length and the jmethodID
1334 // value at index idnum if there is one.
1335 //
1336 void instanceKlass::get_jmethod_id_length_value(jmethodID* cache,
1337        size_t idnum, size_t *length_p, jmethodID* id_p) {
1338   assert(cache != NULL, "sanity check");
1339   assert(length_p != NULL, "sanity check");
1340   assert(id_p != NULL, "sanity check");
1341 
1342   // cache size is stored in element[0], other elements offset by one
1343   *length_p = (size_t)cache[0];
1344   if (*length_p <= idnum) {  // cache is too short
1345     *id_p = NULL;
1346   } else {
1347     *id_p = cache[idnum+1];  // fetch jmethodID (if any)
1348   }
1349 }
1350 
1351 
1352 // Lookup a jmethodID, NULL if not found.  Do no blocking, no allocations, no handles
1353 jmethodID instanceKlass::jmethod_id_or_null(methodOop method) {
1354   size_t idnum = (size_t)method->method_idnum();
1355   jmethodID* jmeths = methods_jmethod_ids_acquire();
1356   size_t length;                                // length assigned as debugging crumb
1357   jmethodID id = NULL;
1358   if (jmeths != NULL &&                         // If there is a cache
1359       (length = (size_t)jmeths[0]) > idnum) {   // and if it is long enough,
1360     id = jmeths[idnum+1];                       // Look up the id (may be NULL)
1361   }
1362   return id;
1363 }
1364 
1365 
1366 // Cache an itable index
1367 void instanceKlass::set_cached_itable_index(size_t idnum, int index) {
1368   int* indices = methods_cached_itable_indices_acquire();
1369   int* to_dealloc_indices = NULL;
1370 
1371   // We use a double-check locking idiom here because this cache is
1372   // performance sensitive. In the normal system, this cache only
1373   // transitions from NULL to non-NULL which is safe because we use
1374   // release_set_methods_cached_itable_indices() to advertise the
1375   // new cache. A partially constructed cache should never be seen
1376   // by a racing thread. Cache reads and writes proceed without a
1377   // lock, but creation of the cache itself requires no leaks so a
1378   // lock is generally acquired in that case.
1379   //
1380   // If the RedefineClasses() API has been used, then this cache can
1381   // grow and we'll have transitions from non-NULL to bigger non-NULL.
1382   // Cache creation requires no leaks and we require safety between all
1383   // cache accesses and freeing of the old cache so a lock is generally
1384   // acquired when the RedefineClasses() API has been used.
1385 
1386   if (indices == NULL || idnum_can_increment()) {
1387     // we need a cache or the cache can grow
1388     MutexLocker ml(JNICachedItableIndex_lock);
1389     // reacquire the cache to see if another thread already did the work
1390     indices = methods_cached_itable_indices_acquire();
1391     size_t length = 0;
1392     // cache size is stored in element[0], other elements offset by one
1393     if (indices == NULL || (length = (size_t)indices[0]) <= idnum) {
1394       size_t size = MAX2(idnum+1, (size_t)idnum_allocated_count());
1395       int* new_indices = NEW_C_HEAP_ARRAY(int, size+1);
1396       new_indices[0] = (int)size;
1397       // copy any existing entries
1398       size_t i;
1399       for (i = 0; i < length; i++) {
1400         new_indices[i+1] = indices[i+1];
1401       }
1402       // Set all the rest to -1
1403       for (i = length; i < size; i++) {
1404         new_indices[i+1] = -1;
1405       }
1406       if (indices != NULL) {
1407         // We have an old cache to delete so save it for after we
1408         // drop the lock.
1409         to_dealloc_indices = indices;
1410       }
1411       release_set_methods_cached_itable_indices(indices = new_indices);
1412     }
1413 
1414     if (idnum_can_increment()) {
1415       // this cache can grow so we have to write to it safely
1416       indices[idnum+1] = index;
1417     }
1418   } else {
1419     CHECK_UNHANDLED_OOPS_ONLY(Thread::current()->clear_unhandled_oops());
1420   }
1421 
1422   if (!idnum_can_increment()) {
1423     // The cache cannot grow and this JNI itable index value does not
1424     // have to be unique like a jmethodID. If there is a race to set it,
1425     // it doesn't matter.
1426     indices[idnum+1] = index;
1427   }
1428 
1429   if (to_dealloc_indices != NULL) {
1430     // we allocated a new cache so free the old one
1431     FreeHeap(to_dealloc_indices);
1432   }
1433 }
1434 
1435 
1436 // Retrieve a cached itable index
1437 int instanceKlass::cached_itable_index(size_t idnum) {
1438   int* indices = methods_cached_itable_indices_acquire();
1439   if (indices != NULL && ((size_t)indices[0]) > idnum) {
1440      // indices exist and are long enough, retrieve possible cached
1441     return indices[idnum+1];
1442   }
1443   return -1;
1444 }
1445 
1446 
1447 //
1448 // Walk the list of dependent nmethods searching for nmethods which
1449 // are dependent on the changes that were passed in and mark them for
1450 // deoptimization.  Returns the number of nmethods found.
1451 //
1452 int instanceKlass::mark_dependent_nmethods(DepChange& changes) {
1453   assert_locked_or_safepoint(CodeCache_lock);
1454   int found = 0;
1455   nmethodBucket* b = _dependencies;
1456   while (b != NULL) {
1457     nmethod* nm = b->get_nmethod();
1458     // since dependencies aren't removed until an nmethod becomes a zombie,
1459     // the dependency list may contain nmethods which aren't alive.
1460     if (nm->is_alive() && !nm->is_marked_for_deoptimization() && nm->check_dependency_on(changes)) {
1461       if (TraceDependencies) {
1462         ResourceMark rm;
1463         tty->print_cr("Marked for deoptimization");
1464         tty->print_cr("  context = %s", this->external_name());
1465         changes.print();
1466         nm->print();
1467         nm->print_dependencies();
1468       }
1469       nm->mark_for_deoptimization();
1470       found++;
1471     }
1472     b = b->next();
1473   }
1474   return found;
1475 }
1476 
1477 
1478 //
1479 // Add an nmethodBucket to the list of dependencies for this nmethod.
1480 // It's possible that an nmethod has multiple dependencies on this klass
1481 // so a count is kept for each bucket to guarantee that creation and
1482 // deletion of dependencies is consistent.
1483 //
1484 void instanceKlass::add_dependent_nmethod(nmethod* nm) {
1485   assert_locked_or_safepoint(CodeCache_lock);
1486   nmethodBucket* b = _dependencies;
1487   nmethodBucket* last = NULL;
1488   while (b != NULL) {
1489     if (nm == b->get_nmethod()) {
1490       b->increment();
1491       return;
1492     }
1493     b = b->next();
1494   }
1495   _dependencies = new nmethodBucket(nm, _dependencies);
1496 }
1497 
1498 
1499 //
1500 // Decrement count of the nmethod in the dependency list and remove
1501 // the bucket competely when the count goes to 0.  This method must
1502 // find a corresponding bucket otherwise there's a bug in the
1503 // recording of dependecies.
1504 //
1505 void instanceKlass::remove_dependent_nmethod(nmethod* nm) {
1506   assert_locked_or_safepoint(CodeCache_lock);
1507   nmethodBucket* b = _dependencies;
1508   nmethodBucket* last = NULL;
1509   while (b != NULL) {
1510     if (nm == b->get_nmethod()) {
1511       if (b->decrement() == 0) {
1512         if (last == NULL) {
1513           _dependencies = b->next();
1514         } else {
1515           last->set_next(b->next());
1516         }
1517         delete b;
1518       }
1519       return;
1520     }
1521     last = b;
1522     b = b->next();
1523   }
1524 #ifdef ASSERT
1525   tty->print_cr("### %s can't find dependent nmethod:", this->external_name());
1526   nm->print();
1527 #endif // ASSERT
1528   ShouldNotReachHere();
1529 }
1530 
1531 
1532 #ifndef PRODUCT
1533 void instanceKlass::print_dependent_nmethods(bool verbose) {
1534   nmethodBucket* b = _dependencies;
1535   int idx = 0;
1536   while (b != NULL) {
1537     nmethod* nm = b->get_nmethod();
1538     tty->print("[%d] count=%d { ", idx++, b->count());
1539     if (!verbose) {
1540       nm->print_on(tty, "nmethod");
1541       tty->print_cr(" } ");
1542     } else {
1543       nm->print();
1544       nm->print_dependencies();
1545       tty->print_cr("--- } ");
1546     }
1547     b = b->next();
1548   }
1549 }
1550 
1551 
1552 bool instanceKlass::is_dependent_nmethod(nmethod* nm) {
1553   nmethodBucket* b = _dependencies;
1554   while (b != NULL) {
1555     if (nm == b->get_nmethod()) {
1556       return true;
1557     }
1558     b = b->next();
1559   }
1560   return false;
1561 }
1562 #endif //PRODUCT
1563 
1564 
1565 #ifdef ASSERT
1566 template <class T> void assert_is_in(T *p) {
1567   T heap_oop = oopDesc::load_heap_oop(p);
1568   if (!oopDesc::is_null(heap_oop)) {
1569     oop o = oopDesc::decode_heap_oop_not_null(heap_oop);
1570     assert(Universe::heap()->is_in(o), "should be in heap");
1571   }
1572 }
1573 template <class T> void assert_is_in_closed_subset(T *p) {
1574   T heap_oop = oopDesc::load_heap_oop(p);
1575   if (!oopDesc::is_null(heap_oop)) {
1576     oop o = oopDesc::decode_heap_oop_not_null(heap_oop);
1577     assert(Universe::heap()->is_in_closed_subset(o), "should be in closed");
1578   }
1579 }
1580 template <class T> void assert_is_in_reserved(T *p) {
1581   T heap_oop = oopDesc::load_heap_oop(p);
1582   if (!oopDesc::is_null(heap_oop)) {
1583     oop o = oopDesc::decode_heap_oop_not_null(heap_oop);
1584     assert(Universe::heap()->is_in_reserved(o), "should be in reserved");
1585   }
1586 }
1587 template <class T> void assert_nothing(T *p) {}
1588 
1589 #else
1590 template <class T> void assert_is_in(T *p) {}
1591 template <class T> void assert_is_in_closed_subset(T *p) {}
1592 template <class T> void assert_is_in_reserved(T *p) {}
1593 template <class T> void assert_nothing(T *p) {}
1594 #endif // ASSERT
1595 
1596 //
1597 // Macros that iterate over areas of oops which are specialized on type of
1598 // oop pointer either narrow or wide, depending on UseCompressedOops
1599 //
1600 // Parameters are:
1601 //   T         - type of oop to point to (either oop or narrowOop)
1602 //   start_p   - starting pointer for region to iterate over
1603 //   count     - number of oops or narrowOops to iterate over
1604 //   do_oop    - action to perform on each oop (it's arbitrary C code which
1605 //               makes it more efficient to put in a macro rather than making
1606 //               it a template function)
1607 //   assert_fn - assert function which is template function because performance
1608 //               doesn't matter when enabled.
1609 #define InstanceKlass_SPECIALIZED_OOP_ITERATE( \
1610   T, start_p, count, do_oop,                \
1611   assert_fn)                                \
1612 {                                           \
1613   T* p         = (T*)(start_p);             \
1614   T* const end = p + (count);               \
1615   while (p < end) {                         \
1616     (assert_fn)(p);                         \
1617     do_oop;                                 \
1618     ++p;                                    \
1619   }                                         \
1620 }
1621 
1622 #define InstanceKlass_SPECIALIZED_OOP_REVERSE_ITERATE( \
1623   T, start_p, count, do_oop,                \
1624   assert_fn)                                \
1625 {                                           \
1626   T* const start = (T*)(start_p);           \
1627   T*       p     = start + (count);         \
1628   while (start < p) {                       \
1629     --p;                                    \
1630     (assert_fn)(p);                         \
1631     do_oop;                                 \
1632   }                                         \
1633 }
1634 
1635 #define InstanceKlass_SPECIALIZED_BOUNDED_OOP_ITERATE( \
1636   T, start_p, count, low, high,             \
1637   do_oop, assert_fn)                        \
1638 {                                           \
1639   T* const l = (T*)(low);                   \
1640   T* const h = (T*)(high);                  \
1641   assert(mask_bits((intptr_t)l, sizeof(T)-1) == 0 && \
1642          mask_bits((intptr_t)h, sizeof(T)-1) == 0,   \
1643          "bounded region must be properly aligned"); \
1644   T* p       = (T*)(start_p);               \
1645   T* end     = p + (count);                 \
1646   if (p < l) p = l;                         \
1647   if (end > h) end = h;                     \
1648   while (p < end) {                         \
1649     (assert_fn)(p);                         \
1650     do_oop;                                 \
1651     ++p;                                    \
1652   }                                         \
1653 }
1654 
1655 
1656 // The following macros call specialized macros, passing either oop or
1657 // narrowOop as the specialization type.  These test the UseCompressedOops
1658 // flag.
1659 #define InstanceKlass_OOP_MAP_ITERATE(obj, do_oop, assert_fn)            \
1660 {                                                                        \
1661   /* Compute oopmap block range. The common case                         \
1662      is nonstatic_oop_map_size == 1. */                                  \
1663   OopMapBlock* map           = start_of_nonstatic_oop_maps();            \
1664   OopMapBlock* const end_map = map + nonstatic_oop_map_count();          \
1665   if (UseCompressedOops) {                                               \
1666     while (map < end_map) {                                              \
1667       InstanceKlass_SPECIALIZED_OOP_ITERATE(narrowOop,                   \
1668         obj->obj_field_addr<narrowOop>(map->offset()), map->count(),     \
1669         do_oop, assert_fn)                                               \
1670       ++map;                                                             \
1671     }                                                                    \
1672   } else {                                                               \
1673     while (map < end_map) {                                              \
1674       InstanceKlass_SPECIALIZED_OOP_ITERATE(oop,                         \
1675         obj->obj_field_addr<oop>(map->offset()), map->count(),           \
1676         do_oop, assert_fn)                                               \
1677       ++map;                                                             \
1678     }                                                                    \
1679   }                                                                      \
1680 }
1681 
1682 #define InstanceKlass_OOP_MAP_REVERSE_ITERATE(obj, do_oop, assert_fn)    \
1683 {                                                                        \
1684   OopMapBlock* const start_map = start_of_nonstatic_oop_maps();          \
1685   OopMapBlock* map             = start_map + nonstatic_oop_map_count();  \
1686   if (UseCompressedOops) {                                               \
1687     while (start_map < map) {                                            \
1688       --map;                                                             \
1689       InstanceKlass_SPECIALIZED_OOP_REVERSE_ITERATE(narrowOop,           \
1690         obj->obj_field_addr<narrowOop>(map->offset()), map->count(),     \
1691         do_oop, assert_fn)                                               \
1692     }                                                                    \
1693   } else {                                                               \
1694     while (start_map < map) {                                            \
1695       --map;                                                             \
1696       InstanceKlass_SPECIALIZED_OOP_REVERSE_ITERATE(oop,                 \
1697         obj->obj_field_addr<oop>(map->offset()), map->count(),           \
1698         do_oop, assert_fn)                                               \
1699     }                                                                    \
1700   }                                                                      \
1701 }
1702 
1703 #define InstanceKlass_BOUNDED_OOP_MAP_ITERATE(obj, low, high, do_oop,    \
1704                                               assert_fn)                 \
1705 {                                                                        \
1706   /* Compute oopmap block range. The common case is                      \
1707      nonstatic_oop_map_size == 1, so we accept the                       \
1708      usually non-existent extra overhead of examining                    \
1709      all the maps. */                                                    \
1710   OopMapBlock* map           = start_of_nonstatic_oop_maps();            \
1711   OopMapBlock* const end_map = map + nonstatic_oop_map_count();          \
1712   if (UseCompressedOops) {                                               \
1713     while (map < end_map) {                                              \
1714       InstanceKlass_SPECIALIZED_BOUNDED_OOP_ITERATE(narrowOop,           \
1715         obj->obj_field_addr<narrowOop>(map->offset()), map->count(),     \
1716         low, high,                                                       \
1717         do_oop, assert_fn)                                               \
1718       ++map;                                                             \
1719     }                                                                    \
1720   } else {                                                               \
1721     while (map < end_map) {                                              \
1722       InstanceKlass_SPECIALIZED_BOUNDED_OOP_ITERATE(oop,                 \
1723         obj->obj_field_addr<oop>(map->offset()), map->count(),           \
1724         low, high,                                                       \
1725         do_oop, assert_fn)                                               \
1726       ++map;                                                             \
1727     }                                                                    \
1728   }                                                                      \
1729 }
1730 
1731 void instanceKlass::oop_follow_contents(oop obj) {
1732   assert(obj != NULL, "can't follow the content of NULL object");
1733   obj->follow_header();
1734   InstanceKlass_OOP_MAP_ITERATE( \
1735     obj, \
1736     MarkSweep::mark_and_push(p), \
1737     assert_is_in_closed_subset)
1738 }
1739 
1740 #ifndef SERIALGC
1741 void instanceKlass::oop_follow_contents(ParCompactionManager* cm,
1742                                         oop obj) {
1743   assert(obj != NULL, "can't follow the content of NULL object");
1744   obj->follow_header(cm);
1745   InstanceKlass_OOP_MAP_ITERATE( \
1746     obj, \
1747     PSParallelCompact::mark_and_push(cm, p), \
1748     assert_is_in)
1749 }
1750 #endif // SERIALGC
1751 
1752 // closure's do_header() method dicates whether the given closure should be
1753 // applied to the klass ptr in the object header.
1754 
1755 #define InstanceKlass_OOP_OOP_ITERATE_DEFN(OopClosureType, nv_suffix)        \
1756                                                                              \
1757 int instanceKlass::oop_oop_iterate##nv_suffix(oop obj, OopClosureType* closure) { \
1758   SpecializationStats::record_iterate_call##nv_suffix(SpecializationStats::ik);\
1759   /* header */                                                          \
1760   if (closure->do_header()) {                                           \
1761     obj->oop_iterate_header(closure);                                   \
1762   }                                                                     \
1763   InstanceKlass_OOP_MAP_ITERATE(                                        \
1764     obj,                                                                \
1765     SpecializationStats::                                               \
1766       record_do_oop_call##nv_suffix(SpecializationStats::ik);           \
1767     (closure)->do_oop##nv_suffix(p),                                    \
1768     assert_is_in_closed_subset)                                         \
1769   return size_helper();                                                 \
1770 }
1771 
1772 #ifndef SERIALGC
1773 #define InstanceKlass_OOP_OOP_ITERATE_BACKWARDS_DEFN(OopClosureType, nv_suffix) \
1774                                                                                 \
1775 int instanceKlass::oop_oop_iterate_backwards##nv_suffix(oop obj,                \
1776                                               OopClosureType* closure) {        \
1777   SpecializationStats::record_iterate_call##nv_suffix(SpecializationStats::ik); \
1778   /* header */                                                                  \
1779   if (closure->do_header()) {                                                   \
1780     obj->oop_iterate_header(closure);                                           \
1781   }                                                                             \
1782   /* instance variables */                                                      \
1783   InstanceKlass_OOP_MAP_REVERSE_ITERATE(                                        \
1784     obj,                                                                        \
1785     SpecializationStats::record_do_oop_call##nv_suffix(SpecializationStats::ik);\
1786     (closure)->do_oop##nv_suffix(p),                                            \
1787     assert_is_in_closed_subset)                                                 \
1788    return size_helper();                                                        \
1789 }
1790 #endif // !SERIALGC
1791 
1792 #define InstanceKlass_OOP_OOP_ITERATE_DEFN_m(OopClosureType, nv_suffix) \
1793                                                                         \
1794 int instanceKlass::oop_oop_iterate##nv_suffix##_m(oop obj,              \
1795                                                   OopClosureType* closure, \
1796                                                   MemRegion mr) {          \
1797   SpecializationStats::record_iterate_call##nv_suffix(SpecializationStats::ik);\
1798   if (closure->do_header()) {                                            \
1799     obj->oop_iterate_header(closure, mr);                                \
1800   }                                                                      \
1801   InstanceKlass_BOUNDED_OOP_MAP_ITERATE(                                 \
1802     obj, mr.start(), mr.end(),                                           \
1803     (closure)->do_oop##nv_suffix(p),                                     \
1804     assert_is_in_closed_subset)                                          \
1805   return size_helper();                                                  \
1806 }
1807 
1808 ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceKlass_OOP_OOP_ITERATE_DEFN)
1809 ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceKlass_OOP_OOP_ITERATE_DEFN)
1810 ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceKlass_OOP_OOP_ITERATE_DEFN_m)
1811 ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceKlass_OOP_OOP_ITERATE_DEFN_m)
1812 #ifndef SERIALGC
1813 ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceKlass_OOP_OOP_ITERATE_BACKWARDS_DEFN)
1814 ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceKlass_OOP_OOP_ITERATE_BACKWARDS_DEFN)
1815 #endif // !SERIALGC
1816 
1817 int instanceKlass::oop_adjust_pointers(oop obj) {
1818   int size = size_helper();
1819   InstanceKlass_OOP_MAP_ITERATE( \
1820     obj, \
1821     MarkSweep::adjust_pointer(p), \
1822     assert_is_in)
1823   obj->adjust_header();
1824   return size;
1825 }
1826 
1827 #ifndef SERIALGC
1828 void instanceKlass::oop_push_contents(PSPromotionManager* pm, oop obj) {
1829   InstanceKlass_OOP_MAP_REVERSE_ITERATE( \
1830     obj, \
1831     if (PSScavenge::should_scavenge(p)) { \
1832       pm->claim_or_forward_depth(p); \
1833     }, \
1834     assert_nothing )
1835 }
1836 
1837 int instanceKlass::oop_update_pointers(ParCompactionManager* cm, oop obj) {
1838   InstanceKlass_OOP_MAP_ITERATE( \
1839     obj, \
1840     PSParallelCompact::adjust_pointer(p), \
1841     assert_nothing)
1842   return size_helper();
1843 }
1844 
1845 #endif // SERIALGC
1846 
1847 // This klass is alive but the implementor link is not followed/updated.
1848 // Subklass and sibling links are handled by Klass::follow_weak_klass_links
1849 
1850 void instanceKlass::follow_weak_klass_links(
1851   BoolObjectClosure* is_alive, OopClosure* keep_alive) {
1852   assert(is_alive->do_object_b(as_klassOop()), "this oop should be live");
1853   if (ClassUnloading) {
1854     for (int i = 0; i < implementors_limit; i++) {
1855       klassOop impl = _implementors[i];
1856       if (impl == NULL)  break;  // no more in the list
1857       if (!is_alive->do_object_b(impl)) {
1858         // remove this guy from the list by overwriting him with the tail
1859         int lasti = --_nof_implementors;
1860         assert(lasti >= i && lasti < implementors_limit, "just checking");
1861         _implementors[i] = _implementors[lasti];
1862         _implementors[lasti] = NULL;
1863         --i; // rerun the loop at this index
1864       }
1865     }
1866   } else {
1867     for (int i = 0; i < implementors_limit; i++) {
1868       keep_alive->do_oop(&adr_implementors()[i]);
1869     }
1870   }
1871   Klass::follow_weak_klass_links(is_alive, keep_alive);
1872 }
1873 
1874 void instanceKlass::remove_unshareable_info() {
1875   Klass::remove_unshareable_info();
1876   init_implementor();
1877 }
1878 
1879 static void clear_all_breakpoints(methodOop m) {
1880   m->clear_all_breakpoints();
1881 }
1882 
1883 void instanceKlass::release_C_heap_structures() {
1884   // Deallocate oop map cache
1885   if (_oop_map_cache != NULL) {
1886     delete _oop_map_cache;
1887     _oop_map_cache = NULL;
1888   }
1889 
1890   // Deallocate JNI identifiers for jfieldIDs
1891   JNIid::deallocate(jni_ids());
1892   set_jni_ids(NULL);
1893 
1894   jmethodID* jmeths = methods_jmethod_ids_acquire();
1895   if (jmeths != (jmethodID*)NULL) {
1896     release_set_methods_jmethod_ids(NULL);
1897     FreeHeap(jmeths);
1898   }
1899 
1900   int* indices = methods_cached_itable_indices_acquire();
1901   if (indices != (int*)NULL) {
1902     release_set_methods_cached_itable_indices(NULL);
1903     FreeHeap(indices);
1904   }
1905 
1906   // release dependencies
1907   nmethodBucket* b = _dependencies;
1908   _dependencies = NULL;
1909   while (b != NULL) {
1910     nmethodBucket* next = b->next();
1911     delete b;
1912     b = next;
1913   }
1914 
1915   // Deallocate breakpoint records
1916   if (breakpoints() != 0x0) {
1917     methods_do(clear_all_breakpoints);
1918     assert(breakpoints() == 0x0, "should have cleared breakpoints");
1919   }
1920 
1921   // deallocate information about previous versions
1922   if (_previous_versions != NULL) {
1923     for (int i = _previous_versions->length() - 1; i >= 0; i--) {
1924       PreviousVersionNode * pv_node = _previous_versions->at(i);
1925       delete pv_node;
1926     }
1927     delete _previous_versions;
1928     _previous_versions = NULL;
1929   }
1930 
1931   // deallocate the cached class file
1932   if (_cached_class_file_bytes != NULL) {
1933     os::free(_cached_class_file_bytes);
1934     _cached_class_file_bytes = NULL;
1935     _cached_class_file_len = 0;
1936   }
1937 
1938   // Decrement symbol reference counts associated with the unloaded class.
1939   if (_name != NULL) _name->decrement_refcount();
1940   // unreference array name derived from this class name (arrays of an unloaded
1941   // class can't be referenced anymore).
1942   if (_array_name != NULL)  _array_name->decrement_refcount();
1943   if (_source_file_name != NULL) _source_file_name->decrement_refcount();
1944   if (_source_debug_extension != NULL) _source_debug_extension->decrement_refcount();
1945   // walk constant pool and decrement symbol reference counts
1946   _constants->unreference_symbols();
1947 }
1948 
1949 void instanceKlass::set_source_file_name(Symbol* n) {
1950   _source_file_name = n;
1951   if (_source_file_name != NULL) _source_file_name->increment_refcount();
1952 }
1953 
1954 void instanceKlass::set_source_debug_extension(Symbol* n) {
1955   _source_debug_extension = n;
1956   if (_source_debug_extension != NULL) _source_debug_extension->increment_refcount();
1957 }
1958 
1959 address instanceKlass::static_field_addr(int offset) {
1960   return (address)(offset + instanceMirrorKlass::offset_of_static_fields() + (intptr_t)java_mirror());
1961 }
1962 
1963 
1964 const char* instanceKlass::signature_name() const {
1965   const char* src = (const char*) (name()->as_C_string());
1966   const int src_length = (int)strlen(src);
1967   char* dest = NEW_RESOURCE_ARRAY(char, src_length + 3);
1968   int src_index = 0;
1969   int dest_index = 0;
1970   dest[dest_index++] = 'L';
1971   while (src_index < src_length) {
1972     dest[dest_index++] = src[src_index++];
1973   }
1974   dest[dest_index++] = ';';
1975   dest[dest_index] = '\0';
1976   return dest;
1977 }
1978 
1979 // different verisons of is_same_class_package
1980 bool instanceKlass::is_same_class_package(klassOop class2) {
1981   klassOop class1 = as_klassOop();
1982   oop classloader1 = instanceKlass::cast(class1)->class_loader();
1983   Symbol* classname1 = Klass::cast(class1)->name();
1984 
1985   if (Klass::cast(class2)->oop_is_objArray()) {
1986     class2 = objArrayKlass::cast(class2)->bottom_klass();
1987   }
1988   oop classloader2;
1989   if (Klass::cast(class2)->oop_is_instance()) {
1990     classloader2 = instanceKlass::cast(class2)->class_loader();
1991   } else {
1992     assert(Klass::cast(class2)->oop_is_typeArray(), "should be type array");
1993     classloader2 = NULL;
1994   }
1995   Symbol* classname2 = Klass::cast(class2)->name();
1996 
1997   return instanceKlass::is_same_class_package(classloader1, classname1,
1998                                               classloader2, classname2);
1999 }
2000 
2001 bool instanceKlass::is_same_class_package(oop classloader2, Symbol* classname2) {
2002   klassOop class1 = as_klassOop();
2003   oop classloader1 = instanceKlass::cast(class1)->class_loader();
2004   Symbol* classname1 = Klass::cast(class1)->name();
2005 
2006   return instanceKlass::is_same_class_package(classloader1, classname1,
2007                                               classloader2, classname2);
2008 }
2009 
2010 // return true if two classes are in the same package, classloader
2011 // and classname information is enough to determine a class's package
2012 bool instanceKlass::is_same_class_package(oop class_loader1, Symbol* class_name1,
2013                                           oop class_loader2, Symbol* class_name2) {
2014   if (class_loader1 != class_loader2) {
2015     return false;
2016   } else if (class_name1 == class_name2) {
2017     return true;                // skip painful bytewise comparison
2018   } else {
2019     ResourceMark rm;
2020 
2021     // The Symbol*'s are in UTF8 encoding. Since we only need to check explicitly
2022     // for ASCII characters ('/', 'L', '['), we can keep them in UTF8 encoding.
2023     // Otherwise, we just compare jbyte values between the strings.
2024     const jbyte *name1 = class_name1->base();
2025     const jbyte *name2 = class_name2->base();
2026 
2027     const jbyte *last_slash1 = UTF8::strrchr(name1, class_name1->utf8_length(), '/');
2028     const jbyte *last_slash2 = UTF8::strrchr(name2, class_name2->utf8_length(), '/');
2029 
2030     if ((last_slash1 == NULL) || (last_slash2 == NULL)) {
2031       // One of the two doesn't have a package.  Only return true
2032       // if the other one also doesn't have a package.
2033       return last_slash1 == last_slash2;
2034     } else {
2035       // Skip over '['s
2036       if (*name1 == '[') {
2037         do {
2038           name1++;
2039         } while (*name1 == '[');
2040         if (*name1 != 'L') {
2041           // Something is terribly wrong.  Shouldn't be here.
2042           return false;
2043         }
2044       }
2045       if (*name2 == '[') {
2046         do {
2047           name2++;
2048         } while (*name2 == '[');
2049         if (*name2 != 'L') {
2050           // Something is terribly wrong.  Shouldn't be here.
2051           return false;
2052         }
2053       }
2054 
2055       // Check that package part is identical
2056       int length1 = last_slash1 - name1;
2057       int length2 = last_slash2 - name2;
2058 
2059       return UTF8::equal(name1, length1, name2, length2);
2060     }
2061   }
2062 }
2063 
2064 // Returns true iff super_method can be overridden by a method in targetclassname
2065 // See JSL 3rd edition 8.4.6.1
2066 // Assumes name-signature match
2067 // "this" is instanceKlass of super_method which must exist
2068 // note that the instanceKlass of the method in the targetclassname has not always been created yet
2069 bool instanceKlass::is_override(methodHandle super_method, Handle targetclassloader, Symbol* targetclassname, TRAPS) {
2070    // Private methods can not be overridden
2071    if (super_method->is_private()) {
2072      return false;
2073    }
2074    // If super method is accessible, then override
2075    if ((super_method->is_protected()) ||
2076        (super_method->is_public())) {
2077      return true;
2078    }
2079    // Package-private methods are not inherited outside of package
2080    assert(super_method->is_package_private(), "must be package private");
2081    return(is_same_class_package(targetclassloader(), targetclassname));
2082 }
2083 
2084 /* defined for now in jvm.cpp, for historical reasons *--
2085 klassOop instanceKlass::compute_enclosing_class_impl(instanceKlassHandle self,
2086                                                      Symbol*& simple_name_result, TRAPS) {
2087   ...
2088 }
2089 */
2090 
2091 // tell if two classes have the same enclosing class (at package level)
2092 bool instanceKlass::is_same_package_member_impl(instanceKlassHandle class1,
2093                                                 klassOop class2_oop, TRAPS) {
2094   if (class2_oop == class1->as_klassOop())          return true;
2095   if (!Klass::cast(class2_oop)->oop_is_instance())  return false;
2096   instanceKlassHandle class2(THREAD, class2_oop);
2097 
2098   // must be in same package before we try anything else
2099   if (!class1->is_same_class_package(class2->class_loader(), class2->name()))
2100     return false;
2101 
2102   // As long as there is an outer1.getEnclosingClass,
2103   // shift the search outward.
2104   instanceKlassHandle outer1 = class1;
2105   for (;;) {
2106     // As we walk along, look for equalities between outer1 and class2.
2107     // Eventually, the walks will terminate as outer1 stops
2108     // at the top-level class around the original class.
2109     bool ignore_inner_is_member;
2110     klassOop next = outer1->compute_enclosing_class(&ignore_inner_is_member,
2111                                                     CHECK_false);
2112     if (next == NULL)  break;
2113     if (next == class2())  return true;
2114     outer1 = instanceKlassHandle(THREAD, next);
2115   }
2116 
2117   // Now do the same for class2.
2118   instanceKlassHandle outer2 = class2;
2119   for (;;) {
2120     bool ignore_inner_is_member;
2121     klassOop next = outer2->compute_enclosing_class(&ignore_inner_is_member,
2122                                                     CHECK_false);
2123     if (next == NULL)  break;
2124     // Might as well check the new outer against all available values.
2125     if (next == class1())  return true;
2126     if (next == outer1())  return true;
2127     outer2 = instanceKlassHandle(THREAD, next);
2128   }
2129 
2130   // If by this point we have not found an equality between the
2131   // two classes, we know they are in separate package members.
2132   return false;
2133 }
2134 
2135 
2136 jint instanceKlass::compute_modifier_flags(TRAPS) const {
2137   klassOop k = as_klassOop();
2138   jint access = access_flags().as_int();
2139 
2140   // But check if it happens to be member class.
2141   typeArrayOop inner_class_list = inner_classes();
2142   int length = (inner_class_list == NULL) ? 0 : inner_class_list->length();
2143   assert ((length % instanceKlass::inner_class_next_offset == 0 ||
2144            length % instanceKlass::inner_class_next_offset == instanceKlass::enclosing_method_attribute_size),
2145            "just checking");
2146   if (length > 0) {
2147     typeArrayHandle inner_class_list_h(THREAD, inner_class_list);
2148     instanceKlassHandle ik(THREAD, k);
2149     for (int i = 0; i < length; i += instanceKlass::inner_class_next_offset) {
2150       if (i == length - instanceKlass::enclosing_method_attribute_size) {
2151         break;
2152       }
2153       int ioff = inner_class_list_h->ushort_at(
2154                       i + instanceKlass::inner_class_inner_class_info_offset);
2155 
2156       // Inner class attribute can be zero, skip it.
2157       // Strange but true:  JVM spec. allows null inner class refs.
2158       if (ioff == 0) continue;
2159 
2160       // only look at classes that are already loaded
2161       // since we are looking for the flags for our self.
2162       Symbol* inner_name = ik->constants()->klass_name_at(ioff);
2163       if ((ik->name() == inner_name)) {
2164         // This is really a member class.
2165         access = inner_class_list_h->ushort_at(i + instanceKlass::inner_class_access_flags_offset);
2166         break;
2167       }
2168     }
2169   }
2170   // Remember to strip ACC_SUPER bit
2171   return (access & (~JVM_ACC_SUPER)) & JVM_ACC_WRITTEN_FLAGS;
2172 }
2173 
2174 jint instanceKlass::jvmti_class_status() const {
2175   jint result = 0;
2176 
2177   if (is_linked()) {
2178     result |= JVMTI_CLASS_STATUS_VERIFIED | JVMTI_CLASS_STATUS_PREPARED;
2179   }
2180 
2181   if (is_initialized()) {
2182     assert(is_linked(), "Class status is not consistent");
2183     result |= JVMTI_CLASS_STATUS_INITIALIZED;
2184   }
2185   if (is_in_error_state()) {
2186     result |= JVMTI_CLASS_STATUS_ERROR;
2187   }
2188   return result;
2189 }
2190 
2191 methodOop instanceKlass::method_at_itable(klassOop holder, int index, TRAPS) {
2192   itableOffsetEntry* ioe = (itableOffsetEntry*)start_of_itable();
2193   int method_table_offset_in_words = ioe->offset()/wordSize;
2194   int nof_interfaces = (method_table_offset_in_words - itable_offset_in_words())
2195                        / itableOffsetEntry::size();
2196 
2197   for (int cnt = 0 ; ; cnt ++, ioe ++) {
2198     // If the interface isn't implemented by the receiver class,
2199     // the VM should throw IncompatibleClassChangeError.
2200     if (cnt >= nof_interfaces) {
2201       THROW_0(vmSymbols::java_lang_IncompatibleClassChangeError());
2202     }
2203 
2204     klassOop ik = ioe->interface_klass();
2205     if (ik == holder) break;
2206   }
2207 
2208   itableMethodEntry* ime = ioe->first_method_entry(as_klassOop());
2209   methodOop m = ime[index].method();
2210   if (m == NULL) {
2211     THROW_0(vmSymbols::java_lang_AbstractMethodError());
2212   }
2213   return m;
2214 }
2215 
2216 // On-stack replacement stuff
2217 void instanceKlass::add_osr_nmethod(nmethod* n) {
2218   // only one compilation can be active
2219   NEEDS_CLEANUP
2220   // This is a short non-blocking critical region, so the no safepoint check is ok.
2221   OsrList_lock->lock_without_safepoint_check();
2222   assert(n->is_osr_method(), "wrong kind of nmethod");
2223   n->set_osr_link(osr_nmethods_head());
2224   set_osr_nmethods_head(n);
2225   // Raise the highest osr level if necessary
2226   if (TieredCompilation) {
2227     methodOop m = n->method();
2228     m->set_highest_osr_comp_level(MAX2(m->highest_osr_comp_level(), n->comp_level()));
2229   }
2230   // Remember to unlock again
2231   OsrList_lock->unlock();
2232 
2233   // Get rid of the osr methods for the same bci that have lower levels.
2234   if (TieredCompilation) {
2235     for (int l = CompLevel_limited_profile; l < n->comp_level(); l++) {
2236       nmethod *inv = lookup_osr_nmethod(n->method(), n->osr_entry_bci(), l, true);
2237       if (inv != NULL && inv->is_in_use()) {
2238         inv->make_not_entrant();
2239       }
2240     }
2241   }
2242 }
2243 
2244 
2245 void instanceKlass::remove_osr_nmethod(nmethod* n) {
2246   // This is a short non-blocking critical region, so the no safepoint check is ok.
2247   OsrList_lock->lock_without_safepoint_check();
2248   assert(n->is_osr_method(), "wrong kind of nmethod");
2249   nmethod* last = NULL;
2250   nmethod* cur  = osr_nmethods_head();
2251   int max_level = CompLevel_none;  // Find the max comp level excluding n
2252   methodOop m = n->method();
2253   // Search for match
2254   while(cur != NULL && cur != n) {
2255     if (TieredCompilation) {
2256       // Find max level before n
2257       max_level = MAX2(max_level, cur->comp_level());
2258     }
2259     last = cur;
2260     cur = cur->osr_link();
2261   }
2262   nmethod* next = NULL;
2263   if (cur == n) {
2264     next = cur->osr_link();
2265     if (last == NULL) {
2266       // Remove first element
2267       set_osr_nmethods_head(next);
2268     } else {
2269       last->set_osr_link(next);
2270     }
2271   }
2272   n->set_osr_link(NULL);
2273   if (TieredCompilation) {
2274     cur = next;
2275     while (cur != NULL) {
2276       // Find max level after n
2277       max_level = MAX2(max_level, cur->comp_level());
2278       cur = cur->osr_link();
2279     }
2280     m->set_highest_osr_comp_level(max_level);
2281   }
2282   // Remember to unlock again
2283   OsrList_lock->unlock();
2284 }
2285 
2286 nmethod* instanceKlass::lookup_osr_nmethod(const methodOop m, int bci, int comp_level, bool match_level) const {
2287   // This is a short non-blocking critical region, so the no safepoint check is ok.
2288   OsrList_lock->lock_without_safepoint_check();
2289   nmethod* osr = osr_nmethods_head();
2290   nmethod* best = NULL;
2291   while (osr != NULL) {
2292     assert(osr->is_osr_method(), "wrong kind of nmethod found in chain");
2293     // There can be a time when a c1 osr method exists but we are waiting
2294     // for a c2 version. When c2 completes its osr nmethod we will trash
2295     // the c1 version and only be able to find the c2 version. However
2296     // while we overflow in the c1 code at back branches we don't want to
2297     // try and switch to the same code as we are already running
2298 
2299     if (osr->method() == m &&
2300         (bci == InvocationEntryBci || osr->osr_entry_bci() == bci)) {
2301       if (match_level) {
2302         if (osr->comp_level() == comp_level) {
2303           // Found a match - return it.
2304           OsrList_lock->unlock();
2305           return osr;
2306         }
2307       } else {
2308         if (best == NULL || (osr->comp_level() > best->comp_level())) {
2309           if (osr->comp_level() == CompLevel_highest_tier) {
2310             // Found the best possible - return it.
2311             OsrList_lock->unlock();
2312             return osr;
2313           }
2314           best = osr;
2315         }
2316       }
2317     }
2318     osr = osr->osr_link();
2319   }
2320   OsrList_lock->unlock();
2321   if (best != NULL && best->comp_level() >= comp_level && match_level == false) {
2322     return best;
2323   }
2324   return NULL;
2325 }
2326 
2327 // -----------------------------------------------------------------------------------------------------
2328 #ifndef PRODUCT
2329 
2330 // Printing
2331 
2332 #define BULLET  " - "
2333 
2334 void FieldPrinter::do_field(fieldDescriptor* fd) {
2335   _st->print(BULLET);
2336    if (_obj == NULL) {
2337      fd->print_on(_st);
2338      _st->cr();
2339    } else {
2340      fd->print_on_for(_st, _obj);
2341      _st->cr();
2342    }
2343 }
2344 
2345 
2346 void instanceKlass::oop_print_on(oop obj, outputStream* st) {
2347   Klass::oop_print_on(obj, st);
2348 
2349   if (as_klassOop() == SystemDictionary::String_klass()) {
2350     typeArrayOop value  = java_lang_String::value(obj);
2351     juint        offset = java_lang_String::offset(obj);
2352     juint        length = java_lang_String::length(obj);
2353     if (value != NULL &&
2354         value->is_typeArray() &&
2355         offset          <= (juint) value->length() &&
2356         offset + length <= (juint) value->length()) {
2357       st->print(BULLET"string: ");
2358       Handle h_obj(obj);
2359       java_lang_String::print(h_obj, st);
2360       st->cr();
2361       if (!WizardMode)  return;  // that is enough
2362     }
2363   }
2364 
2365   st->print_cr(BULLET"---- fields (total size %d words):", oop_size(obj));
2366   FieldPrinter print_field(st, obj);
2367   do_nonstatic_fields(&print_field);
2368 
2369   if (as_klassOop() == SystemDictionary::Class_klass()) {
2370     st->print(BULLET"signature: ");
2371     java_lang_Class::print_signature(obj, st);
2372     st->cr();
2373     klassOop mirrored_klass = java_lang_Class::as_klassOop(obj);
2374     st->print(BULLET"fake entry for mirror: ");
2375     mirrored_klass->print_value_on(st);
2376     st->cr();
2377     st->print(BULLET"fake entry resolved_constructor: ");
2378     methodOop ctor = java_lang_Class::resolved_constructor(obj);
2379     ctor->print_value_on(st);
2380     klassOop array_klass = java_lang_Class::array_klass(obj);
2381     st->cr();
2382     st->print(BULLET"fake entry for array: ");
2383     array_klass->print_value_on(st);
2384     st->cr();
2385     st->print_cr(BULLET"fake entry for oop_size: %d", java_lang_Class::oop_size(obj));
2386     st->print_cr(BULLET"fake entry for static_oop_field_count: %d", java_lang_Class::static_oop_field_count(obj));
2387     klassOop real_klass = java_lang_Class::as_klassOop(obj);
2388     if (real_klass != NULL && real_klass->klass_part()->oop_is_instance()) {
2389       instanceKlass::cast(real_klass)->do_local_static_fields(&print_field);
2390     }
2391   } else if (as_klassOop() == SystemDictionary::MethodType_klass()) {
2392     st->print(BULLET"signature: ");
2393     java_lang_invoke_MethodType::print_signature(obj, st);
2394     st->cr();
2395   }
2396 }
2397 
2398 #endif //PRODUCT
2399 
2400 void instanceKlass::oop_print_value_on(oop obj, outputStream* st) {
2401   st->print("a ");
2402   name()->print_value_on(st);
2403   obj->print_address_on(st);
2404   if (as_klassOop() == SystemDictionary::String_klass()
2405       && java_lang_String::value(obj) != NULL) {
2406     ResourceMark rm;
2407     int len = java_lang_String::length(obj);
2408     int plen = (len < 24 ? len : 12);
2409     char* str = java_lang_String::as_utf8_string(obj, 0, plen);
2410     st->print(" = \"%s\"", str);
2411     if (len > plen)
2412       st->print("...[%d]", len);
2413   } else if (as_klassOop() == SystemDictionary::Class_klass()) {
2414     klassOop k = java_lang_Class::as_klassOop(obj);
2415     st->print(" = ");
2416     if (k != NULL) {
2417       k->print_value_on(st);
2418     } else {
2419       const char* tname = type2name(java_lang_Class::primitive_type(obj));
2420       st->print("%s", tname ? tname : "type?");
2421     }
2422   } else if (as_klassOop() == SystemDictionary::MethodType_klass()) {
2423     st->print(" = ");
2424     java_lang_invoke_MethodType::print_signature(obj, st);
2425   } else if (java_lang_boxing_object::is_instance(obj)) {
2426     st->print(" = ");
2427     java_lang_boxing_object::print(obj, st);
2428   }
2429 }
2430 
2431 const char* instanceKlass::internal_name() const {
2432   return external_name();
2433 }
2434 
2435 // Verification
2436 
2437 class VerifyFieldClosure: public OopClosure {
2438  protected:
2439   template <class T> void do_oop_work(T* p) {
2440     guarantee(Universe::heap()->is_in_closed_subset(p), "should be in heap");
2441     oop obj = oopDesc::load_decode_heap_oop(p);
2442     if (!obj->is_oop_or_null()) {
2443       tty->print_cr("Failed: " PTR_FORMAT " -> " PTR_FORMAT, p, (address)obj);
2444       Universe::print();
2445       guarantee(false, "boom");
2446     }
2447   }
2448  public:
2449   virtual void do_oop(oop* p)       { VerifyFieldClosure::do_oop_work(p); }
2450   virtual void do_oop(narrowOop* p) { VerifyFieldClosure::do_oop_work(p); }
2451 };
2452 
2453 void instanceKlass::oop_verify_on(oop obj, outputStream* st) {
2454   Klass::oop_verify_on(obj, st);
2455   VerifyFieldClosure blk;
2456   oop_oop_iterate(obj, &blk);
2457 }
2458 
2459 // JNIid class for jfieldIDs only
2460 // Note to reviewers:
2461 // These JNI functions are just moved over to column 1 and not changed
2462 // in the compressed oops workspace.
2463 JNIid::JNIid(klassOop holder, int offset, JNIid* next) {
2464   _holder = holder;
2465   _offset = offset;
2466   _next = next;
2467   debug_only(_is_static_field_id = false;)
2468 }
2469 
2470 
2471 JNIid* JNIid::find(int offset) {
2472   JNIid* current = this;
2473   while (current != NULL) {
2474     if (current->offset() == offset) return current;
2475     current = current->next();
2476   }
2477   return NULL;
2478 }
2479 
2480 void JNIid::oops_do(OopClosure* f) {
2481   for (JNIid* cur = this; cur != NULL; cur = cur->next()) {
2482     f->do_oop(cur->holder_addr());
2483   }
2484 }
2485 
2486 void JNIid::deallocate(JNIid* current) {
2487   while (current != NULL) {
2488     JNIid* next = current->next();
2489     delete current;
2490     current = next;
2491   }
2492 }
2493 
2494 
2495 void JNIid::verify(klassOop holder) {
2496   int first_field_offset  = instanceMirrorKlass::offset_of_static_fields();
2497   int end_field_offset;
2498   end_field_offset = first_field_offset + (instanceKlass::cast(holder)->static_field_size() * wordSize);
2499 
2500   JNIid* current = this;
2501   while (current != NULL) {
2502     guarantee(current->holder() == holder, "Invalid klass in JNIid");
2503 #ifdef ASSERT
2504     int o = current->offset();
2505     if (current->is_static_field_id()) {
2506       guarantee(o >= first_field_offset  && o < end_field_offset,  "Invalid static field offset in JNIid");
2507     }
2508 #endif
2509     current = current->next();
2510   }
2511 }
2512 
2513 
2514 #ifdef ASSERT
2515 void instanceKlass::set_init_state(ClassState state) {
2516   bool good_state = as_klassOop()->is_shared() ? (_init_state <= state)
2517                                                : (_init_state < state);
2518   assert(good_state || state == allocated, "illegal state transition");
2519   _init_state = (u1)state;
2520 }
2521 #endif
2522 
2523 
2524 // RedefineClasses() support for previous versions:
2525 
2526 // Add an information node that contains weak references to the
2527 // interesting parts of the previous version of the_class.
2528 // This is also where we clean out any unused weak references.
2529 // Note that while we delete nodes from the _previous_versions
2530 // array, we never delete the array itself until the klass is
2531 // unloaded. The has_been_redefined() query depends on that fact.
2532 //
2533 void instanceKlass::add_previous_version(instanceKlassHandle ikh,
2534        BitMap* emcp_methods, int emcp_method_count) {
2535   assert(Thread::current()->is_VM_thread(),
2536          "only VMThread can add previous versions");
2537 
2538   if (_previous_versions == NULL) {
2539     // This is the first previous version so make some space.
2540     // Start with 2 elements under the assumption that the class
2541     // won't be redefined much.
2542     _previous_versions =  new (ResourceObj::C_HEAP)
2543                             GrowableArray<PreviousVersionNode *>(2, true);
2544   }
2545 
2546   // RC_TRACE macro has an embedded ResourceMark
2547   RC_TRACE(0x00000100, ("adding previous version ref for %s @%d, EMCP_cnt=%d",
2548     ikh->external_name(), _previous_versions->length(), emcp_method_count));
2549   constantPoolHandle cp_h(ikh->constants());
2550   jobject cp_ref;
2551   if (cp_h->is_shared()) {
2552     // a shared ConstantPool requires a regular reference; a weak
2553     // reference would be collectible
2554     cp_ref = JNIHandles::make_global(cp_h);
2555   } else {
2556     cp_ref = JNIHandles::make_weak_global(cp_h);
2557   }
2558   PreviousVersionNode * pv_node = NULL;
2559   objArrayOop old_methods = ikh->methods();
2560 
2561   if (emcp_method_count == 0) {
2562     // non-shared ConstantPool gets a weak reference
2563     pv_node = new PreviousVersionNode(cp_ref, !cp_h->is_shared(), NULL);
2564     RC_TRACE(0x00000400,
2565       ("add: all methods are obsolete; flushing any EMCP weak refs"));
2566   } else {
2567     int local_count = 0;
2568     GrowableArray<jweak>* method_refs = new (ResourceObj::C_HEAP)
2569       GrowableArray<jweak>(emcp_method_count, true);
2570     for (int i = 0; i < old_methods->length(); i++) {
2571       if (emcp_methods->at(i)) {
2572         // this old method is EMCP so save a weak ref
2573         methodOop old_method = (methodOop) old_methods->obj_at(i);
2574         methodHandle old_method_h(old_method);
2575         jweak method_ref = JNIHandles::make_weak_global(old_method_h);
2576         method_refs->append(method_ref);
2577         if (++local_count >= emcp_method_count) {
2578           // no more EMCP methods so bail out now
2579           break;
2580         }
2581       }
2582     }
2583     // non-shared ConstantPool gets a weak reference
2584     pv_node = new PreviousVersionNode(cp_ref, !cp_h->is_shared(), method_refs);
2585   }
2586 
2587   _previous_versions->append(pv_node);
2588 
2589   // Using weak references allows the interesting parts of previous
2590   // classes to be GC'ed when they are no longer needed. Since the
2591   // caller is the VMThread and we are at a safepoint, this is a good
2592   // time to clear out unused weak references.
2593 
2594   RC_TRACE(0x00000400, ("add: previous version length=%d",
2595     _previous_versions->length()));
2596 
2597   // skip the last entry since we just added it
2598   for (int i = _previous_versions->length() - 2; i >= 0; i--) {
2599     // check the previous versions array for a GC'ed weak refs
2600     pv_node = _previous_versions->at(i);
2601     cp_ref = pv_node->prev_constant_pool();
2602     assert(cp_ref != NULL, "cp ref was unexpectedly cleared");
2603     if (cp_ref == NULL) {
2604       delete pv_node;
2605       _previous_versions->remove_at(i);
2606       // Since we are traversing the array backwards, we don't have to
2607       // do anything special with the index.
2608       continue;  // robustness
2609     }
2610 
2611     constantPoolOop cp = (constantPoolOop)JNIHandles::resolve(cp_ref);
2612     if (cp == NULL) {
2613       // this entry has been GC'ed so remove it
2614       delete pv_node;
2615       _previous_versions->remove_at(i);
2616       // Since we are traversing the array backwards, we don't have to
2617       // do anything special with the index.
2618       continue;
2619     } else {
2620       RC_TRACE(0x00000400, ("add: previous version @%d is alive", i));
2621     }
2622 
2623     GrowableArray<jweak>* method_refs = pv_node->prev_EMCP_methods();
2624     if (method_refs != NULL) {
2625       RC_TRACE(0x00000400, ("add: previous methods length=%d",
2626         method_refs->length()));
2627       for (int j = method_refs->length() - 1; j >= 0; j--) {
2628         jweak method_ref = method_refs->at(j);
2629         assert(method_ref != NULL, "weak method ref was unexpectedly cleared");
2630         if (method_ref == NULL) {
2631           method_refs->remove_at(j);
2632           // Since we are traversing the array backwards, we don't have to
2633           // do anything special with the index.
2634           continue;  // robustness
2635         }
2636 
2637         methodOop method = (methodOop)JNIHandles::resolve(method_ref);
2638         if (method == NULL || emcp_method_count == 0) {
2639           // This method entry has been GC'ed or the current
2640           // RedefineClasses() call has made all methods obsolete
2641           // so remove it.
2642           JNIHandles::destroy_weak_global(method_ref);
2643           method_refs->remove_at(j);
2644         } else {
2645           // RC_TRACE macro has an embedded ResourceMark
2646           RC_TRACE(0x00000400,
2647             ("add: %s(%s): previous method @%d in version @%d is alive",
2648             method->name()->as_C_string(), method->signature()->as_C_string(),
2649             j, i));
2650         }
2651       }
2652     }
2653   }
2654 
2655   int obsolete_method_count = old_methods->length() - emcp_method_count;
2656 
2657   if (emcp_method_count != 0 && obsolete_method_count != 0 &&
2658       _previous_versions->length() > 1) {
2659     // We have a mix of obsolete and EMCP methods. If there is more
2660     // than the previous version that we just added, then we have to
2661     // clear out any matching EMCP method entries the hard way.
2662     int local_count = 0;
2663     for (int i = 0; i < old_methods->length(); i++) {
2664       if (!emcp_methods->at(i)) {
2665         // only obsolete methods are interesting
2666         methodOop old_method = (methodOop) old_methods->obj_at(i);
2667         Symbol* m_name = old_method->name();
2668         Symbol* m_signature = old_method->signature();
2669 
2670         // skip the last entry since we just added it
2671         for (int j = _previous_versions->length() - 2; j >= 0; j--) {
2672           // check the previous versions array for a GC'ed weak refs
2673           pv_node = _previous_versions->at(j);
2674           cp_ref = pv_node->prev_constant_pool();
2675           assert(cp_ref != NULL, "cp ref was unexpectedly cleared");
2676           if (cp_ref == NULL) {
2677             delete pv_node;
2678             _previous_versions->remove_at(j);
2679             // Since we are traversing the array backwards, we don't have to
2680             // do anything special with the index.
2681             continue;  // robustness
2682           }
2683 
2684           constantPoolOop cp = (constantPoolOop)JNIHandles::resolve(cp_ref);
2685           if (cp == NULL) {
2686             // this entry has been GC'ed so remove it
2687             delete pv_node;
2688             _previous_versions->remove_at(j);
2689             // Since we are traversing the array backwards, we don't have to
2690             // do anything special with the index.
2691             continue;
2692           }
2693 
2694           GrowableArray<jweak>* method_refs = pv_node->prev_EMCP_methods();
2695           if (method_refs == NULL) {
2696             // We have run into a PreviousVersion generation where
2697             // all methods were made obsolete during that generation's
2698             // RedefineClasses() operation. At the time of that
2699             // operation, all EMCP methods were flushed so we don't
2700             // have to go back any further.
2701             //
2702             // A NULL method_refs is different than an empty method_refs.
2703             // We cannot infer any optimizations about older generations
2704             // from an empty method_refs for the current generation.
2705             break;
2706           }
2707 
2708           for (int k = method_refs->length() - 1; k >= 0; k--) {
2709             jweak method_ref = method_refs->at(k);
2710             assert(method_ref != NULL,
2711               "weak method ref was unexpectedly cleared");
2712             if (method_ref == NULL) {
2713               method_refs->remove_at(k);
2714               // Since we are traversing the array backwards, we don't
2715               // have to do anything special with the index.
2716               continue;  // robustness
2717             }
2718 
2719             methodOop method = (methodOop)JNIHandles::resolve(method_ref);
2720             if (method == NULL) {
2721               // this method entry has been GC'ed so skip it
2722               JNIHandles::destroy_weak_global(method_ref);
2723               method_refs->remove_at(k);
2724               continue;
2725             }
2726 
2727             if (method->name() == m_name &&
2728                 method->signature() == m_signature) {
2729               // The current RedefineClasses() call has made all EMCP
2730               // versions of this method obsolete so mark it as obsolete
2731               // and remove the weak ref.
2732               RC_TRACE(0x00000400,
2733                 ("add: %s(%s): flush obsolete method @%d in version @%d",
2734                 m_name->as_C_string(), m_signature->as_C_string(), k, j));
2735 
2736               method->set_is_obsolete();
2737               JNIHandles::destroy_weak_global(method_ref);
2738               method_refs->remove_at(k);
2739               break;
2740             }
2741           }
2742 
2743           // The previous loop may not find a matching EMCP method, but
2744           // that doesn't mean that we can optimize and not go any
2745           // further back in the PreviousVersion generations. The EMCP
2746           // method for this generation could have already been GC'ed,
2747           // but there still may be an older EMCP method that has not
2748           // been GC'ed.
2749         }
2750 
2751         if (++local_count >= obsolete_method_count) {
2752           // no more obsolete methods so bail out now
2753           break;
2754         }
2755       }
2756     }
2757   }
2758 } // end add_previous_version()
2759 
2760 
2761 // Determine if instanceKlass has a previous version.
2762 bool instanceKlass::has_previous_version() const {
2763   if (_previous_versions == NULL) {
2764     // no previous versions array so answer is easy
2765     return false;
2766   }
2767 
2768   for (int i = _previous_versions->length() - 1; i >= 0; i--) {
2769     // Check the previous versions array for an info node that hasn't
2770     // been GC'ed
2771     PreviousVersionNode * pv_node = _previous_versions->at(i);
2772 
2773     jobject cp_ref = pv_node->prev_constant_pool();
2774     assert(cp_ref != NULL, "cp reference was unexpectedly cleared");
2775     if (cp_ref == NULL) {
2776       continue;  // robustness
2777     }
2778 
2779     constantPoolOop cp = (constantPoolOop)JNIHandles::resolve(cp_ref);
2780     if (cp != NULL) {
2781       // we have at least one previous version
2782       return true;
2783     }
2784 
2785     // We don't have to check the method refs. If the constant pool has
2786     // been GC'ed then so have the methods.
2787   }
2788 
2789   // all of the underlying nodes' info has been GC'ed
2790   return false;
2791 } // end has_previous_version()
2792 
2793 methodOop instanceKlass::method_with_idnum(int idnum) {
2794   methodOop m = NULL;
2795   if (idnum < methods()->length()) {
2796     m = (methodOop) methods()->obj_at(idnum);
2797   }
2798   if (m == NULL || m->method_idnum() != idnum) {
2799     for (int index = 0; index < methods()->length(); ++index) {
2800       m = (methodOop) methods()->obj_at(index);
2801       if (m->method_idnum() == idnum) {
2802         return m;
2803       }
2804     }
2805   }
2806   return m;
2807 }
2808 
2809 
2810 // Set the annotation at 'idnum' to 'anno'.
2811 // We don't want to create or extend the array if 'anno' is NULL, since that is the
2812 // default value.  However, if the array exists and is long enough, we must set NULL values.
2813 void instanceKlass::set_methods_annotations_of(int idnum, typeArrayOop anno, objArrayOop* md_p) {
2814   objArrayOop md = *md_p;
2815   if (md != NULL && md->length() > idnum) {
2816     md->obj_at_put(idnum, anno);
2817   } else if (anno != NULL) {
2818     // create the array
2819     int length = MAX2(idnum+1, (int)_idnum_allocated_count);
2820     md = oopFactory::new_system_objArray(length, Thread::current());
2821     if (*md_p != NULL) {
2822       // copy the existing entries
2823       for (int index = 0; index < (*md_p)->length(); index++) {
2824         md->obj_at_put(index, (*md_p)->obj_at(index));
2825       }
2826     }
2827     set_annotations(md, md_p);
2828     md->obj_at_put(idnum, anno);
2829   } // if no array and idnum isn't included there is nothing to do
2830 }
2831 
2832 // Construct a PreviousVersionNode entry for the array hung off
2833 // the instanceKlass.
2834 PreviousVersionNode::PreviousVersionNode(jobject prev_constant_pool,
2835   bool prev_cp_is_weak, GrowableArray<jweak>* prev_EMCP_methods) {
2836 
2837   _prev_constant_pool = prev_constant_pool;
2838   _prev_cp_is_weak = prev_cp_is_weak;
2839   _prev_EMCP_methods = prev_EMCP_methods;
2840 }
2841 
2842 
2843 // Destroy a PreviousVersionNode
2844 PreviousVersionNode::~PreviousVersionNode() {
2845   if (_prev_constant_pool != NULL) {
2846     if (_prev_cp_is_weak) {
2847       JNIHandles::destroy_weak_global(_prev_constant_pool);
2848     } else {
2849       JNIHandles::destroy_global(_prev_constant_pool);
2850     }
2851   }
2852 
2853   if (_prev_EMCP_methods != NULL) {
2854     for (int i = _prev_EMCP_methods->length() - 1; i >= 0; i--) {
2855       jweak method_ref = _prev_EMCP_methods->at(i);
2856       if (method_ref != NULL) {
2857         JNIHandles::destroy_weak_global(method_ref);
2858       }
2859     }
2860     delete _prev_EMCP_methods;
2861   }
2862 }
2863 
2864 
2865 // Construct a PreviousVersionInfo entry
2866 PreviousVersionInfo::PreviousVersionInfo(PreviousVersionNode *pv_node) {
2867   _prev_constant_pool_handle = constantPoolHandle();  // NULL handle
2868   _prev_EMCP_method_handles = NULL;
2869 
2870   jobject cp_ref = pv_node->prev_constant_pool();
2871   assert(cp_ref != NULL, "constant pool ref was unexpectedly cleared");
2872   if (cp_ref == NULL) {
2873     return;  // robustness
2874   }
2875 
2876   constantPoolOop cp = (constantPoolOop)JNIHandles::resolve(cp_ref);
2877   if (cp == NULL) {
2878     // Weak reference has been GC'ed. Since the constant pool has been
2879     // GC'ed, the methods have also been GC'ed.
2880     return;
2881   }
2882 
2883   // make the constantPoolOop safe to return
2884   _prev_constant_pool_handle = constantPoolHandle(cp);
2885 
2886   GrowableArray<jweak>* method_refs = pv_node->prev_EMCP_methods();
2887   if (method_refs == NULL) {
2888     // the instanceKlass did not have any EMCP methods
2889     return;
2890   }
2891 
2892   _prev_EMCP_method_handles = new GrowableArray<methodHandle>(10);
2893 
2894   int n_methods = method_refs->length();
2895   for (int i = 0; i < n_methods; i++) {
2896     jweak method_ref = method_refs->at(i);
2897     assert(method_ref != NULL, "weak method ref was unexpectedly cleared");
2898     if (method_ref == NULL) {
2899       continue;  // robustness
2900     }
2901 
2902     methodOop method = (methodOop)JNIHandles::resolve(method_ref);
2903     if (method == NULL) {
2904       // this entry has been GC'ed so skip it
2905       continue;
2906     }
2907 
2908     // make the methodOop safe to return
2909     _prev_EMCP_method_handles->append(methodHandle(method));
2910   }
2911 }
2912 
2913 
2914 // Destroy a PreviousVersionInfo
2915 PreviousVersionInfo::~PreviousVersionInfo() {
2916   // Since _prev_EMCP_method_handles is not C-heap allocated, we
2917   // don't have to delete it.
2918 }
2919 
2920 
2921 // Construct a helper for walking the previous versions array
2922 PreviousVersionWalker::PreviousVersionWalker(instanceKlass *ik) {
2923   _previous_versions = ik->previous_versions();
2924   _current_index = 0;
2925   // _hm needs no initialization
2926   _current_p = NULL;
2927 }
2928 
2929 
2930 // Destroy a PreviousVersionWalker
2931 PreviousVersionWalker::~PreviousVersionWalker() {
2932   // Delete the current info just in case the caller didn't walk to
2933   // the end of the previous versions list. No harm if _current_p is
2934   // already NULL.
2935   delete _current_p;
2936 
2937   // When _hm is destroyed, all the Handles returned in
2938   // PreviousVersionInfo objects will be destroyed.
2939   // Also, after this destructor is finished it will be
2940   // safe to delete the GrowableArray allocated in the
2941   // PreviousVersionInfo objects.
2942 }
2943 
2944 
2945 // Return the interesting information for the next previous version
2946 // of the klass. Returns NULL if there are no more previous versions.
2947 PreviousVersionInfo* PreviousVersionWalker::next_previous_version() {
2948   if (_previous_versions == NULL) {
2949     // no previous versions so nothing to return
2950     return NULL;
2951   }
2952 
2953   delete _current_p;  // cleanup the previous info for the caller
2954   _current_p = NULL;  // reset to NULL so we don't delete same object twice
2955 
2956   int length = _previous_versions->length();
2957 
2958   while (_current_index < length) {
2959     PreviousVersionNode * pv_node = _previous_versions->at(_current_index++);
2960     PreviousVersionInfo * pv_info = new (ResourceObj::C_HEAP)
2961                                           PreviousVersionInfo(pv_node);
2962 
2963     constantPoolHandle cp_h = pv_info->prev_constant_pool_handle();
2964     if (cp_h.is_null()) {
2965       delete pv_info;
2966 
2967       // The underlying node's info has been GC'ed so try the next one.
2968       // We don't have to check the methods. If the constant pool has
2969       // GC'ed then so have the methods.
2970       continue;
2971     }
2972 
2973     // Found a node with non GC'ed info so return it. The caller will
2974     // need to delete pv_info when they are done with it.
2975     _current_p = pv_info;
2976     return pv_info;
2977   }
2978 
2979   // all of the underlying nodes' info has been GC'ed
2980   return NULL;
2981 } // end next_previous_version()