src/share/vm/oops/instanceKlass.cpp

Fri, 03 Sep 2010 17:51:07 -0700

author
iveresov
date
Fri, 03 Sep 2010 17:51:07 -0700
changeset 2138
d5d065957597
parent 2106
2528b5bd749c
child 2314
f95d63e2154a
permissions
-rw-r--r--

6953144: Tiered compilation
Summary: Infrastructure for tiered compilation support (interpreter + c1 + c2) for 32 and 64 bit. Simple tiered policy implementation.
Reviewed-by: kvn, never, phh, twisti

     1 /*
     2  * Copyright (c) 1997, 2010, 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  */
    25 # include "incls/_precompiled.incl"
    26 # include "incls/_instanceKlass.cpp.incl"
    28 #ifdef DTRACE_ENABLED
    30 HS_DTRACE_PROBE_DECL4(hotspot, class__initialization__required,
    31   char*, intptr_t, oop, intptr_t);
    32 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__recursive,
    33   char*, intptr_t, oop, intptr_t, int);
    34 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__concurrent,
    35   char*, intptr_t, oop, intptr_t, int);
    36 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__erroneous,
    37   char*, intptr_t, oop, intptr_t, int);
    38 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__super__failed,
    39   char*, intptr_t, oop, intptr_t, int);
    40 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__clinit,
    41   char*, intptr_t, oop, intptr_t, int);
    42 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__error,
    43   char*, intptr_t, oop, intptr_t, int);
    44 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__end,
    45   char*, intptr_t, oop, intptr_t, int);
    47 #define DTRACE_CLASSINIT_PROBE(type, clss, thread_type)          \
    48   {                                                              \
    49     char* data = NULL;                                           \
    50     int len = 0;                                                 \
    51     symbolOop name = (clss)->name();                             \
    52     if (name != NULL) {                                          \
    53       data = (char*)name->bytes();                               \
    54       len = name->utf8_length();                                 \
    55     }                                                            \
    56     HS_DTRACE_PROBE4(hotspot, class__initialization__##type,     \
    57       data, len, (clss)->class_loader(), thread_type);           \
    58   }
    60 #define DTRACE_CLASSINIT_PROBE_WAIT(type, clss, thread_type, wait) \
    61   {                                                              \
    62     char* data = NULL;                                           \
    63     int len = 0;                                                 \
    64     symbolOop name = (clss)->name();                             \
    65     if (name != NULL) {                                          \
    66       data = (char*)name->bytes();                               \
    67       len = name->utf8_length();                                 \
    68     }                                                            \
    69     HS_DTRACE_PROBE5(hotspot, class__initialization__##type,     \
    70       data, len, (clss)->class_loader(), thread_type, wait);     \
    71   }
    73 #else //  ndef DTRACE_ENABLED
    75 #define DTRACE_CLASSINIT_PROBE(type, clss, thread_type)
    76 #define DTRACE_CLASSINIT_PROBE_WAIT(type, clss, thread_type, wait)
    78 #endif //  ndef DTRACE_ENABLED
    80 bool instanceKlass::should_be_initialized() const {
    81   return !is_initialized();
    82 }
    84 klassVtable* instanceKlass::vtable() const {
    85   return new klassVtable(as_klassOop(), start_of_vtable(), vtable_length() / vtableEntry::size());
    86 }
    88 klassItable* instanceKlass::itable() const {
    89   return new klassItable(as_klassOop());
    90 }
    92 void instanceKlass::eager_initialize(Thread *thread) {
    93   if (!EagerInitialization) return;
    95   if (this->is_not_initialized()) {
    96     // abort if the the class has a class initializer
    97     if (this->class_initializer() != NULL) return;
    99     // abort if it is java.lang.Object (initialization is handled in genesis)
   100     klassOop super = this->super();
   101     if (super == NULL) return;
   103     // abort if the super class should be initialized
   104     if (!instanceKlass::cast(super)->is_initialized()) return;
   106     // call body to expose the this pointer
   107     instanceKlassHandle this_oop(thread, this->as_klassOop());
   108     eager_initialize_impl(this_oop);
   109   }
   110 }
   113 void instanceKlass::eager_initialize_impl(instanceKlassHandle this_oop) {
   114   EXCEPTION_MARK;
   115   ObjectLocker ol(this_oop, THREAD);
   117   // abort if someone beat us to the initialization
   118   if (!this_oop->is_not_initialized()) return;  // note: not equivalent to is_initialized()
   120   ClassState old_state = this_oop->_init_state;
   121   link_class_impl(this_oop, true, THREAD);
   122   if (HAS_PENDING_EXCEPTION) {
   123     CLEAR_PENDING_EXCEPTION;
   124     // Abort if linking the class throws an exception.
   126     // Use a test to avoid redundantly resetting the state if there's
   127     // no change.  Set_init_state() asserts that state changes make
   128     // progress, whereas here we might just be spinning in place.
   129     if( old_state != this_oop->_init_state )
   130       this_oop->set_init_state (old_state);
   131   } else {
   132     // linking successfull, mark class as initialized
   133     this_oop->set_init_state (fully_initialized);
   134     // trace
   135     if (TraceClassInitialization) {
   136       ResourceMark rm(THREAD);
   137       tty->print_cr("[Initialized %s without side effects]", this_oop->external_name());
   138     }
   139   }
   140 }
   143 // See "The Virtual Machine Specification" section 2.16.5 for a detailed explanation of the class initialization
   144 // process. The step comments refers to the procedure described in that section.
   145 // Note: implementation moved to static method to expose the this pointer.
   146 void instanceKlass::initialize(TRAPS) {
   147   if (this->should_be_initialized()) {
   148     HandleMark hm(THREAD);
   149     instanceKlassHandle this_oop(THREAD, this->as_klassOop());
   150     initialize_impl(this_oop, CHECK);
   151     // Note: at this point the class may be initialized
   152     //       OR it may be in the state of being initialized
   153     //       in case of recursive initialization!
   154   } else {
   155     assert(is_initialized(), "sanity check");
   156   }
   157 }
   160 bool instanceKlass::verify_code(
   161     instanceKlassHandle this_oop, bool throw_verifyerror, TRAPS) {
   162   // 1) Verify the bytecodes
   163   Verifier::Mode mode =
   164     throw_verifyerror ? Verifier::ThrowException : Verifier::NoException;
   165   return Verifier::verify(this_oop, mode, this_oop->should_verify_class(), CHECK_false);
   166 }
   169 // Used exclusively by the shared spaces dump mechanism to prevent
   170 // classes mapped into the shared regions in new VMs from appearing linked.
   172 void instanceKlass::unlink_class() {
   173   assert(is_linked(), "must be linked");
   174   _init_state = loaded;
   175 }
   177 void instanceKlass::link_class(TRAPS) {
   178   assert(is_loaded(), "must be loaded");
   179   if (!is_linked()) {
   180     instanceKlassHandle this_oop(THREAD, this->as_klassOop());
   181     link_class_impl(this_oop, true, CHECK);
   182   }
   183 }
   185 // Called to verify that a class can link during initialization, without
   186 // throwing a VerifyError.
   187 bool instanceKlass::link_class_or_fail(TRAPS) {
   188   assert(is_loaded(), "must be loaded");
   189   if (!is_linked()) {
   190     instanceKlassHandle this_oop(THREAD, this->as_klassOop());
   191     link_class_impl(this_oop, false, CHECK_false);
   192   }
   193   return is_linked();
   194 }
   196 bool instanceKlass::link_class_impl(
   197     instanceKlassHandle this_oop, bool throw_verifyerror, TRAPS) {
   198   // check for error state
   199   if (this_oop->is_in_error_state()) {
   200     ResourceMark rm(THREAD);
   201     THROW_MSG_(vmSymbols::java_lang_NoClassDefFoundError(),
   202                this_oop->external_name(), false);
   203   }
   204   // return if already verified
   205   if (this_oop->is_linked()) {
   206     return true;
   207   }
   209   // Timing
   210   // timer handles recursion
   211   assert(THREAD->is_Java_thread(), "non-JavaThread in link_class_impl");
   212   JavaThread* jt = (JavaThread*)THREAD;
   214   // link super class before linking this class
   215   instanceKlassHandle super(THREAD, this_oop->super());
   216   if (super.not_null()) {
   217     if (super->is_interface()) {  // check if super class is an interface
   218       ResourceMark rm(THREAD);
   219       Exceptions::fthrow(
   220         THREAD_AND_LOCATION,
   221         vmSymbolHandles::java_lang_IncompatibleClassChangeError(),
   222         "class %s has interface %s as super class",
   223         this_oop->external_name(),
   224         super->external_name()
   225       );
   226       return false;
   227     }
   229     link_class_impl(super, throw_verifyerror, CHECK_false);
   230   }
   232   // link all interfaces implemented by this class before linking this class
   233   objArrayHandle interfaces (THREAD, this_oop->local_interfaces());
   234   int num_interfaces = interfaces->length();
   235   for (int index = 0; index < num_interfaces; index++) {
   236     HandleMark hm(THREAD);
   237     instanceKlassHandle ih(THREAD, klassOop(interfaces->obj_at(index)));
   238     link_class_impl(ih, throw_verifyerror, CHECK_false);
   239   }
   241   // in case the class is linked in the process of linking its superclasses
   242   if (this_oop->is_linked()) {
   243     return true;
   244   }
   246   // trace only the link time for this klass that includes
   247   // the verification time
   248   PerfClassTraceTime vmtimer(ClassLoader::perf_class_link_time(),
   249                              ClassLoader::perf_class_link_selftime(),
   250                              ClassLoader::perf_classes_linked(),
   251                              jt->get_thread_stat()->perf_recursion_counts_addr(),
   252                              jt->get_thread_stat()->perf_timers_addr(),
   253                              PerfClassTraceTime::CLASS_LINK);
   255   // verification & rewriting
   256   {
   257     ObjectLocker ol(this_oop, THREAD);
   258     // rewritten will have been set if loader constraint error found
   259     // on an earlier link attempt
   260     // don't verify or rewrite if already rewritten
   261     if (!this_oop->is_linked()) {
   262       if (!this_oop->is_rewritten()) {
   263         {
   264           // Timer includes any side effects of class verification (resolution,
   265           // etc), but not recursive entry into verify_code().
   266           PerfClassTraceTime timer(ClassLoader::perf_class_verify_time(),
   267                                    ClassLoader::perf_class_verify_selftime(),
   268                                    ClassLoader::perf_classes_verified(),
   269                                    jt->get_thread_stat()->perf_recursion_counts_addr(),
   270                                    jt->get_thread_stat()->perf_timers_addr(),
   271                                    PerfClassTraceTime::CLASS_VERIFY);
   272           bool verify_ok = verify_code(this_oop, throw_verifyerror, THREAD);
   273           if (!verify_ok) {
   274             return false;
   275           }
   276         }
   278         // Just in case a side-effect of verify linked this class already
   279         // (which can sometimes happen since the verifier loads classes
   280         // using custom class loaders, which are free to initialize things)
   281         if (this_oop->is_linked()) {
   282           return true;
   283         }
   285         // also sets rewritten
   286         this_oop->rewrite_class(CHECK_false);
   287       }
   289       // Initialize the vtable and interface table after
   290       // methods have been rewritten since rewrite may
   291       // fabricate new methodOops.
   292       // also does loader constraint checking
   293       if (!this_oop()->is_shared()) {
   294         ResourceMark rm(THREAD);
   295         this_oop->vtable()->initialize_vtable(true, CHECK_false);
   296         this_oop->itable()->initialize_itable(true, CHECK_false);
   297       }
   298 #ifdef ASSERT
   299       else {
   300         ResourceMark rm(THREAD);
   301         this_oop->vtable()->verify(tty, true);
   302         // In case itable verification is ever added.
   303         // this_oop->itable()->verify(tty, true);
   304       }
   305 #endif
   306       this_oop->set_init_state(linked);
   307       if (JvmtiExport::should_post_class_prepare()) {
   308         Thread *thread = THREAD;
   309         assert(thread->is_Java_thread(), "thread->is_Java_thread()");
   310         JvmtiExport::post_class_prepare((JavaThread *) thread, this_oop());
   311       }
   312     }
   313   }
   314   return true;
   315 }
   318 // Rewrite the byte codes of all of the methods of a class.
   319 // Three cases:
   320 //    During the link of a newly loaded class.
   321 //    During the preloading of classes to be written to the shared spaces.
   322 //      - Rewrite the methods and update the method entry points.
   323 //
   324 //    During the link of a class in the shared spaces.
   325 //      - The methods were already rewritten, update the metho entry points.
   326 //
   327 // The rewriter must be called exactly once. Rewriting must happen after
   328 // verification but before the first method of the class is executed.
   330 void instanceKlass::rewrite_class(TRAPS) {
   331   assert(is_loaded(), "must be loaded");
   332   instanceKlassHandle this_oop(THREAD, this->as_klassOop());
   333   if (this_oop->is_rewritten()) {
   334     assert(this_oop()->is_shared(), "rewriting an unshared class?");
   335     return;
   336   }
   337   Rewriter::rewrite(this_oop, CHECK); // No exception can happen here
   338   this_oop->set_rewritten();
   339 }
   342 void instanceKlass::initialize_impl(instanceKlassHandle this_oop, TRAPS) {
   343   // Make sure klass is linked (verified) before initialization
   344   // A class could already be verified, since it has been reflected upon.
   345   this_oop->link_class(CHECK);
   347   DTRACE_CLASSINIT_PROBE(required, instanceKlass::cast(this_oop()), -1);
   349   bool wait = false;
   351   // refer to the JVM book page 47 for description of steps
   352   // Step 1
   353   { ObjectLocker ol(this_oop, THREAD);
   355     Thread *self = THREAD; // it's passed the current thread
   357     // Step 2
   358     // If we were to use wait() instead of waitInterruptibly() then
   359     // we might end up throwing IE from link/symbol resolution sites
   360     // that aren't expected to throw.  This would wreak havoc.  See 6320309.
   361     while(this_oop->is_being_initialized() && !this_oop->is_reentrant_initialization(self)) {
   362         wait = true;
   363       ol.waitUninterruptibly(CHECK);
   364     }
   366     // Step 3
   367     if (this_oop->is_being_initialized() && this_oop->is_reentrant_initialization(self)) {
   368       DTRACE_CLASSINIT_PROBE_WAIT(recursive, instanceKlass::cast(this_oop()), -1,wait);
   369       return;
   370     }
   372     // Step 4
   373     if (this_oop->is_initialized()) {
   374       DTRACE_CLASSINIT_PROBE_WAIT(concurrent, instanceKlass::cast(this_oop()), -1,wait);
   375       return;
   376     }
   378     // Step 5
   379     if (this_oop->is_in_error_state()) {
   380       DTRACE_CLASSINIT_PROBE_WAIT(erroneous, instanceKlass::cast(this_oop()), -1,wait);
   381       ResourceMark rm(THREAD);
   382       const char* desc = "Could not initialize class ";
   383       const char* className = this_oop->external_name();
   384       size_t msglen = strlen(desc) + strlen(className) + 1;
   385       char* message = NEW_RESOURCE_ARRAY(char, msglen);
   386       if (NULL == message) {
   387         // Out of memory: can't create detailed error message
   388         THROW_MSG(vmSymbols::java_lang_NoClassDefFoundError(), className);
   389       } else {
   390         jio_snprintf(message, msglen, "%s%s", desc, className);
   391         THROW_MSG(vmSymbols::java_lang_NoClassDefFoundError(), message);
   392       }
   393     }
   395     // Step 6
   396     this_oop->set_init_state(being_initialized);
   397     this_oop->set_init_thread(self);
   398   }
   400   // Step 7
   401   klassOop super_klass = this_oop->super();
   402   if (super_klass != NULL && !this_oop->is_interface() && Klass::cast(super_klass)->should_be_initialized()) {
   403     Klass::cast(super_klass)->initialize(THREAD);
   405     if (HAS_PENDING_EXCEPTION) {
   406       Handle e(THREAD, PENDING_EXCEPTION);
   407       CLEAR_PENDING_EXCEPTION;
   408       {
   409         EXCEPTION_MARK;
   410         this_oop->set_initialization_state_and_notify(initialization_error, THREAD); // Locks object, set state, and notify all waiting threads
   411         CLEAR_PENDING_EXCEPTION;   // ignore any exception thrown, superclass initialization error is thrown below
   412       }
   413       DTRACE_CLASSINIT_PROBE_WAIT(super__failed, instanceKlass::cast(this_oop()), -1,wait);
   414       THROW_OOP(e());
   415     }
   416   }
   418   // Step 8
   419   {
   420     assert(THREAD->is_Java_thread(), "non-JavaThread in initialize_impl");
   421     JavaThread* jt = (JavaThread*)THREAD;
   422     DTRACE_CLASSINIT_PROBE_WAIT(clinit, instanceKlass::cast(this_oop()), -1,wait);
   423     // Timer includes any side effects of class initialization (resolution,
   424     // etc), but not recursive entry into call_class_initializer().
   425     PerfClassTraceTime timer(ClassLoader::perf_class_init_time(),
   426                              ClassLoader::perf_class_init_selftime(),
   427                              ClassLoader::perf_classes_inited(),
   428                              jt->get_thread_stat()->perf_recursion_counts_addr(),
   429                              jt->get_thread_stat()->perf_timers_addr(),
   430                              PerfClassTraceTime::CLASS_CLINIT);
   431     this_oop->call_class_initializer(THREAD);
   432   }
   434   // Step 9
   435   if (!HAS_PENDING_EXCEPTION) {
   436     this_oop->set_initialization_state_and_notify(fully_initialized, CHECK);
   437     { ResourceMark rm(THREAD);
   438       debug_only(this_oop->vtable()->verify(tty, true);)
   439     }
   440   }
   441   else {
   442     // Step 10 and 11
   443     Handle e(THREAD, PENDING_EXCEPTION);
   444     CLEAR_PENDING_EXCEPTION;
   445     {
   446       EXCEPTION_MARK;
   447       this_oop->set_initialization_state_and_notify(initialization_error, THREAD);
   448       CLEAR_PENDING_EXCEPTION;   // ignore any exception thrown, class initialization error is thrown below
   449     }
   450     DTRACE_CLASSINIT_PROBE_WAIT(error, instanceKlass::cast(this_oop()), -1,wait);
   451     if (e->is_a(SystemDictionary::Error_klass())) {
   452       THROW_OOP(e());
   453     } else {
   454       JavaCallArguments args(e);
   455       THROW_ARG(vmSymbolHandles::java_lang_ExceptionInInitializerError(),
   456                 vmSymbolHandles::throwable_void_signature(),
   457                 &args);
   458     }
   459   }
   460   DTRACE_CLASSINIT_PROBE_WAIT(end, instanceKlass::cast(this_oop()), -1,wait);
   461 }
   464 // Note: implementation moved to static method to expose the this pointer.
   465 void instanceKlass::set_initialization_state_and_notify(ClassState state, TRAPS) {
   466   instanceKlassHandle kh(THREAD, this->as_klassOop());
   467   set_initialization_state_and_notify_impl(kh, state, CHECK);
   468 }
   470 void instanceKlass::set_initialization_state_and_notify_impl(instanceKlassHandle this_oop, ClassState state, TRAPS) {
   471   ObjectLocker ol(this_oop, THREAD);
   472   this_oop->set_init_state(state);
   473   ol.notify_all(CHECK);
   474 }
   476 void instanceKlass::add_implementor(klassOop k) {
   477   assert(Compile_lock->owned_by_self(), "");
   478   // Filter out my subinterfaces.
   479   // (Note: Interfaces are never on the subklass list.)
   480   if (instanceKlass::cast(k)->is_interface()) return;
   482   // Filter out subclasses whose supers already implement me.
   483   // (Note: CHA must walk subclasses of direct implementors
   484   // in order to locate indirect implementors.)
   485   klassOop sk = instanceKlass::cast(k)->super();
   486   if (sk != NULL && instanceKlass::cast(sk)->implements_interface(as_klassOop()))
   487     // We only need to check one immediate superclass, since the
   488     // implements_interface query looks at transitive_interfaces.
   489     // Any supers of the super have the same (or fewer) transitive_interfaces.
   490     return;
   492   // Update number of implementors
   493   int i = _nof_implementors++;
   495   // Record this implementor, if there are not too many already
   496   if (i < implementors_limit) {
   497     assert(_implementors[i] == NULL, "should be exactly one implementor");
   498     oop_store_without_check((oop*)&_implementors[i], k);
   499   } else if (i == implementors_limit) {
   500     // clear out the list on first overflow
   501     for (int i2 = 0; i2 < implementors_limit; i2++)
   502       oop_store_without_check((oop*)&_implementors[i2], NULL);
   503   }
   505   // The implementor also implements the transitive_interfaces
   506   for (int index = 0; index < local_interfaces()->length(); index++) {
   507     instanceKlass::cast(klassOop(local_interfaces()->obj_at(index)))->add_implementor(k);
   508   }
   509 }
   511 void instanceKlass::init_implementor() {
   512   for (int i = 0; i < implementors_limit; i++)
   513     oop_store_without_check((oop*)&_implementors[i], NULL);
   514   _nof_implementors = 0;
   515 }
   518 void instanceKlass::process_interfaces(Thread *thread) {
   519   // link this class into the implementors list of every interface it implements
   520   KlassHandle this_as_oop (thread, this->as_klassOop());
   521   for (int i = local_interfaces()->length() - 1; i >= 0; i--) {
   522     assert(local_interfaces()->obj_at(i)->is_klass(), "must be a klass");
   523     instanceKlass* interf = instanceKlass::cast(klassOop(local_interfaces()->obj_at(i)));
   524     assert(interf->is_interface(), "expected interface");
   525     interf->add_implementor(this_as_oop());
   526   }
   527 }
   529 bool instanceKlass::can_be_primary_super_slow() const {
   530   if (is_interface())
   531     return false;
   532   else
   533     return Klass::can_be_primary_super_slow();
   534 }
   536 objArrayOop instanceKlass::compute_secondary_supers(int num_extra_slots, TRAPS) {
   537   // The secondaries are the implemented interfaces.
   538   instanceKlass* ik = instanceKlass::cast(as_klassOop());
   539   objArrayHandle interfaces (THREAD, ik->transitive_interfaces());
   540   int num_secondaries = num_extra_slots + interfaces->length();
   541   if (num_secondaries == 0) {
   542     return Universe::the_empty_system_obj_array();
   543   } else if (num_extra_slots == 0) {
   544     return interfaces();
   545   } else {
   546     // a mix of both
   547     objArrayOop secondaries = oopFactory::new_system_objArray(num_secondaries, CHECK_NULL);
   548     for (int i = 0; i < interfaces->length(); i++) {
   549       secondaries->obj_at_put(num_extra_slots+i, interfaces->obj_at(i));
   550     }
   551     return secondaries;
   552   }
   553 }
   555 bool instanceKlass::compute_is_subtype_of(klassOop k) {
   556   if (Klass::cast(k)->is_interface()) {
   557     return implements_interface(k);
   558   } else {
   559     return Klass::compute_is_subtype_of(k);
   560   }
   561 }
   563 bool instanceKlass::implements_interface(klassOop k) const {
   564   if (as_klassOop() == k) return true;
   565   assert(Klass::cast(k)->is_interface(), "should be an interface class");
   566   for (int i = 0; i < transitive_interfaces()->length(); i++) {
   567     if (transitive_interfaces()->obj_at(i) == k) {
   568       return true;
   569     }
   570   }
   571   return false;
   572 }
   574 objArrayOop instanceKlass::allocate_objArray(int n, int length, TRAPS) {
   575   if (length < 0) THROW_0(vmSymbols::java_lang_NegativeArraySizeException());
   576   if (length > arrayOopDesc::max_array_length(T_OBJECT)) {
   577     report_java_out_of_memory("Requested array size exceeds VM limit");
   578     THROW_OOP_0(Universe::out_of_memory_error_array_size());
   579   }
   580   int size = objArrayOopDesc::object_size(length);
   581   klassOop ak = array_klass(n, CHECK_NULL);
   582   KlassHandle h_ak (THREAD, ak);
   583   objArrayOop o =
   584     (objArrayOop)CollectedHeap::array_allocate(h_ak, size, length, CHECK_NULL);
   585   return o;
   586 }
   588 instanceOop instanceKlass::register_finalizer(instanceOop i, TRAPS) {
   589   if (TraceFinalizerRegistration) {
   590     tty->print("Registered ");
   591     i->print_value_on(tty);
   592     tty->print_cr(" (" INTPTR_FORMAT ") as finalizable", (address)i);
   593   }
   594   instanceHandle h_i(THREAD, i);
   595   // Pass the handle as argument, JavaCalls::call expects oop as jobjects
   596   JavaValue result(T_VOID);
   597   JavaCallArguments args(h_i);
   598   methodHandle mh (THREAD, Universe::finalizer_register_method());
   599   JavaCalls::call(&result, mh, &args, CHECK_NULL);
   600   return h_i();
   601 }
   603 instanceOop instanceKlass::allocate_instance(TRAPS) {
   604   bool has_finalizer_flag = has_finalizer(); // Query before possible GC
   605   int size = size_helper();  // Query before forming handle.
   607   KlassHandle h_k(THREAD, as_klassOop());
   609   instanceOop i;
   611   i = (instanceOop)CollectedHeap::obj_allocate(h_k, size, CHECK_NULL);
   612   if (has_finalizer_flag && !RegisterFinalizersAtInit) {
   613     i = register_finalizer(i, CHECK_NULL);
   614   }
   615   return i;
   616 }
   618 instanceOop instanceKlass::allocate_permanent_instance(TRAPS) {
   619   // Finalizer registration occurs in the Object.<init> constructor
   620   // and constructors normally aren't run when allocating perm
   621   // instances so simply disallow finalizable perm objects.  This can
   622   // be relaxed if a need for it is found.
   623   assert(!has_finalizer(), "perm objects not allowed to have finalizers");
   624   int size = size_helper();  // Query before forming handle.
   625   KlassHandle h_k(THREAD, as_klassOop());
   626   instanceOop i = (instanceOop)
   627     CollectedHeap::permanent_obj_allocate(h_k, size, CHECK_NULL);
   628   return i;
   629 }
   631 void instanceKlass::check_valid_for_instantiation(bool throwError, TRAPS) {
   632   if (is_interface() || is_abstract()) {
   633     ResourceMark rm(THREAD);
   634     THROW_MSG(throwError ? vmSymbols::java_lang_InstantiationError()
   635               : vmSymbols::java_lang_InstantiationException(), external_name());
   636   }
   637   if (as_klassOop() == SystemDictionary::Class_klass()) {
   638     ResourceMark rm(THREAD);
   639     THROW_MSG(throwError ? vmSymbols::java_lang_IllegalAccessError()
   640               : vmSymbols::java_lang_IllegalAccessException(), external_name());
   641   }
   642 }
   644 klassOop instanceKlass::array_klass_impl(bool or_null, int n, TRAPS) {
   645   instanceKlassHandle this_oop(THREAD, as_klassOop());
   646   return array_klass_impl(this_oop, or_null, n, THREAD);
   647 }
   649 klassOop instanceKlass::array_klass_impl(instanceKlassHandle this_oop, bool or_null, int n, TRAPS) {
   650   if (this_oop->array_klasses() == NULL) {
   651     if (or_null) return NULL;
   653     ResourceMark rm;
   654     JavaThread *jt = (JavaThread *)THREAD;
   655     {
   656       // Atomic creation of array_klasses
   657       MutexLocker mc(Compile_lock, THREAD);   // for vtables
   658       MutexLocker ma(MultiArray_lock, THREAD);
   660       // Check if update has already taken place
   661       if (this_oop->array_klasses() == NULL) {
   662         objArrayKlassKlass* oakk =
   663           (objArrayKlassKlass*)Universe::objArrayKlassKlassObj()->klass_part();
   665         klassOop  k = oakk->allocate_objArray_klass(1, this_oop, CHECK_NULL);
   666         this_oop->set_array_klasses(k);
   667       }
   668     }
   669   }
   670   // _this will always be set at this point
   671   objArrayKlass* oak = (objArrayKlass*)this_oop->array_klasses()->klass_part();
   672   if (or_null) {
   673     return oak->array_klass_or_null(n);
   674   }
   675   return oak->array_klass(n, CHECK_NULL);
   676 }
   678 klassOop instanceKlass::array_klass_impl(bool or_null, TRAPS) {
   679   return array_klass_impl(or_null, 1, THREAD);
   680 }
   682 void instanceKlass::call_class_initializer(TRAPS) {
   683   instanceKlassHandle ik (THREAD, as_klassOop());
   684   call_class_initializer_impl(ik, THREAD);
   685 }
   687 static int call_class_initializer_impl_counter = 0;   // for debugging
   689 methodOop instanceKlass::class_initializer() {
   690   return find_method(vmSymbols::class_initializer_name(), vmSymbols::void_method_signature());
   691 }
   693 void instanceKlass::call_class_initializer_impl(instanceKlassHandle this_oop, TRAPS) {
   694   methodHandle h_method(THREAD, this_oop->class_initializer());
   695   assert(!this_oop->is_initialized(), "we cannot initialize twice");
   696   if (TraceClassInitialization) {
   697     tty->print("%d Initializing ", call_class_initializer_impl_counter++);
   698     this_oop->name()->print_value();
   699     tty->print_cr("%s (" INTPTR_FORMAT ")", h_method() == NULL ? "(no method)" : "", (address)this_oop());
   700   }
   701   if (h_method() != NULL) {
   702     JavaCallArguments args; // No arguments
   703     JavaValue result(T_VOID);
   704     JavaCalls::call(&result, h_method, &args, CHECK); // Static call (no args)
   705   }
   706 }
   709 void instanceKlass::mask_for(methodHandle method, int bci,
   710   InterpreterOopMap* entry_for) {
   711   // Dirty read, then double-check under a lock.
   712   if (_oop_map_cache == NULL) {
   713     // Otherwise, allocate a new one.
   714     MutexLocker x(OopMapCacheAlloc_lock);
   715     // First time use. Allocate a cache in C heap
   716     if (_oop_map_cache == NULL) {
   717       _oop_map_cache = new OopMapCache();
   718     }
   719   }
   720   // _oop_map_cache is constant after init; lookup below does is own locking.
   721   _oop_map_cache->lookup(method, bci, entry_for);
   722 }
   725 bool instanceKlass::find_local_field(symbolOop name, symbolOop sig, fieldDescriptor* fd) const {
   726   const int n = fields()->length();
   727   for (int i = 0; i < n; i += next_offset ) {
   728     int name_index = fields()->ushort_at(i + name_index_offset);
   729     int sig_index  = fields()->ushort_at(i + signature_index_offset);
   730     symbolOop f_name = constants()->symbol_at(name_index);
   731     symbolOop f_sig  = constants()->symbol_at(sig_index);
   732     if (f_name == name && f_sig == sig) {
   733       fd->initialize(as_klassOop(), i);
   734       return true;
   735     }
   736   }
   737   return false;
   738 }
   741 void instanceKlass::field_names_and_sigs_iterate(OopClosure* closure) {
   742   const int n = fields()->length();
   743   for (int i = 0; i < n; i += next_offset ) {
   744     int name_index = fields()->ushort_at(i + name_index_offset);
   745     symbolOop name = constants()->symbol_at(name_index);
   746     closure->do_oop((oop*)&name);
   748     int sig_index  = fields()->ushort_at(i + signature_index_offset);
   749     symbolOop sig = constants()->symbol_at(sig_index);
   750     closure->do_oop((oop*)&sig);
   751   }
   752 }
   755 klassOop instanceKlass::find_interface_field(symbolOop name, symbolOop sig, fieldDescriptor* fd) const {
   756   const int n = local_interfaces()->length();
   757   for (int i = 0; i < n; i++) {
   758     klassOop intf1 = klassOop(local_interfaces()->obj_at(i));
   759     assert(Klass::cast(intf1)->is_interface(), "just checking type");
   760     // search for field in current interface
   761     if (instanceKlass::cast(intf1)->find_local_field(name, sig, fd)) {
   762       assert(fd->is_static(), "interface field must be static");
   763       return intf1;
   764     }
   765     // search for field in direct superinterfaces
   766     klassOop intf2 = instanceKlass::cast(intf1)->find_interface_field(name, sig, fd);
   767     if (intf2 != NULL) return intf2;
   768   }
   769   // otherwise field lookup fails
   770   return NULL;
   771 }
   774 klassOop instanceKlass::find_field(symbolOop name, symbolOop sig, fieldDescriptor* fd) const {
   775   // search order according to newest JVM spec (5.4.3.2, p.167).
   776   // 1) search for field in current klass
   777   if (find_local_field(name, sig, fd)) {
   778     return as_klassOop();
   779   }
   780   // 2) search for field recursively in direct superinterfaces
   781   { klassOop intf = find_interface_field(name, sig, fd);
   782     if (intf != NULL) return intf;
   783   }
   784   // 3) apply field lookup recursively if superclass exists
   785   { klassOop supr = super();
   786     if (supr != NULL) return instanceKlass::cast(supr)->find_field(name, sig, fd);
   787   }
   788   // 4) otherwise field lookup fails
   789   return NULL;
   790 }
   793 klassOop instanceKlass::find_field(symbolOop name, symbolOop sig, bool is_static, fieldDescriptor* fd) const {
   794   // search order according to newest JVM spec (5.4.3.2, p.167).
   795   // 1) search for field in current klass
   796   if (find_local_field(name, sig, fd)) {
   797     if (fd->is_static() == is_static) return as_klassOop();
   798   }
   799   // 2) search for field recursively in direct superinterfaces
   800   if (is_static) {
   801     klassOop intf = find_interface_field(name, sig, fd);
   802     if (intf != NULL) return intf;
   803   }
   804   // 3) apply field lookup recursively if superclass exists
   805   { klassOop supr = super();
   806     if (supr != NULL) return instanceKlass::cast(supr)->find_field(name, sig, is_static, fd);
   807   }
   808   // 4) otherwise field lookup fails
   809   return NULL;
   810 }
   813 bool instanceKlass::find_local_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const {
   814   int length = fields()->length();
   815   for (int i = 0; i < length; i += next_offset) {
   816     if (offset_from_fields( i ) == offset) {
   817       fd->initialize(as_klassOop(), i);
   818       if (fd->is_static() == is_static) return true;
   819     }
   820   }
   821   return false;
   822 }
   825 bool instanceKlass::find_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const {
   826   klassOop klass = as_klassOop();
   827   while (klass != NULL) {
   828     if (instanceKlass::cast(klass)->find_local_field_from_offset(offset, is_static, fd)) {
   829       return true;
   830     }
   831     klass = Klass::cast(klass)->super();
   832   }
   833   return false;
   834 }
   837 void instanceKlass::methods_do(void f(methodOop method)) {
   838   int len = methods()->length();
   839   for (int index = 0; index < len; index++) {
   840     methodOop m = methodOop(methods()->obj_at(index));
   841     assert(m->is_method(), "must be method");
   842     f(m);
   843   }
   844 }
   846 void instanceKlass::do_local_static_fields(FieldClosure* cl) {
   847   fieldDescriptor fd;
   848   int length = fields()->length();
   849   for (int i = 0; i < length; i += next_offset) {
   850     fd.initialize(as_klassOop(), i);
   851     if (fd.is_static()) cl->do_field(&fd);
   852   }
   853 }
   856 void instanceKlass::do_local_static_fields(void f(fieldDescriptor*, TRAPS), TRAPS) {
   857   instanceKlassHandle h_this(THREAD, as_klassOop());
   858   do_local_static_fields_impl(h_this, f, CHECK);
   859 }
   862 void instanceKlass::do_local_static_fields_impl(instanceKlassHandle this_oop, void f(fieldDescriptor* fd, TRAPS), TRAPS) {
   863   fieldDescriptor fd;
   864   int length = this_oop->fields()->length();
   865   for (int i = 0; i < length; i += next_offset) {
   866     fd.initialize(this_oop(), i);
   867     if (fd.is_static()) { f(&fd, CHECK); } // Do NOT remove {}! (CHECK macro expands into several statements)
   868   }
   869 }
   872 static int compare_fields_by_offset(int* a, int* b) {
   873   return a[0] - b[0];
   874 }
   876 void instanceKlass::do_nonstatic_fields(FieldClosure* cl) {
   877   instanceKlass* super = superklass();
   878   if (super != NULL) {
   879     super->do_nonstatic_fields(cl);
   880   }
   881   fieldDescriptor fd;
   882   int length = fields()->length();
   883   // In DebugInfo nonstatic fields are sorted by offset.
   884   int* fields_sorted = NEW_C_HEAP_ARRAY(int, 2*(length+1));
   885   int j = 0;
   886   for (int i = 0; i < length; i += next_offset) {
   887     fd.initialize(as_klassOop(), i);
   888     if (!fd.is_static()) {
   889       fields_sorted[j + 0] = fd.offset();
   890       fields_sorted[j + 1] = i;
   891       j += 2;
   892     }
   893   }
   894   if (j > 0) {
   895     length = j;
   896     // _sort_Fn is defined in growableArray.hpp.
   897     qsort(fields_sorted, length/2, 2*sizeof(int), (_sort_Fn)compare_fields_by_offset);
   898     for (int i = 0; i < length; i += 2) {
   899       fd.initialize(as_klassOop(), fields_sorted[i + 1]);
   900       assert(!fd.is_static() && fd.offset() == fields_sorted[i], "only nonstatic fields");
   901       cl->do_field(&fd);
   902     }
   903   }
   904   FREE_C_HEAP_ARRAY(int, fields_sorted);
   905 }
   908 void instanceKlass::array_klasses_do(void f(klassOop k)) {
   909   if (array_klasses() != NULL)
   910     arrayKlass::cast(array_klasses())->array_klasses_do(f);
   911 }
   914 void instanceKlass::with_array_klasses_do(void f(klassOop k)) {
   915   f(as_klassOop());
   916   array_klasses_do(f);
   917 }
   919 #ifdef ASSERT
   920 static int linear_search(objArrayOop methods, symbolOop name, symbolOop signature) {
   921   int len = methods->length();
   922   for (int index = 0; index < len; index++) {
   923     methodOop m = (methodOop)(methods->obj_at(index));
   924     assert(m->is_method(), "must be method");
   925     if (m->signature() == signature && m->name() == name) {
   926        return index;
   927     }
   928   }
   929   return -1;
   930 }
   931 #endif
   933 methodOop instanceKlass::find_method(symbolOop name, symbolOop signature) const {
   934   return instanceKlass::find_method(methods(), name, signature);
   935 }
   937 methodOop instanceKlass::find_method(objArrayOop methods, symbolOop name, symbolOop signature) {
   938   int len = methods->length();
   939   // methods are sorted, so do binary search
   940   int l = 0;
   941   int h = len - 1;
   942   while (l <= h) {
   943     int mid = (l + h) >> 1;
   944     methodOop m = (methodOop)methods->obj_at(mid);
   945     assert(m->is_method(), "must be method");
   946     int res = m->name()->fast_compare(name);
   947     if (res == 0) {
   948       // found matching name; do linear search to find matching signature
   949       // first, quick check for common case
   950       if (m->signature() == signature) return m;
   951       // search downwards through overloaded methods
   952       int i;
   953       for (i = mid - 1; i >= l; i--) {
   954         methodOop m = (methodOop)methods->obj_at(i);
   955         assert(m->is_method(), "must be method");
   956         if (m->name() != name) break;
   957         if (m->signature() == signature) return m;
   958       }
   959       // search upwards
   960       for (i = mid + 1; i <= h; i++) {
   961         methodOop m = (methodOop)methods->obj_at(i);
   962         assert(m->is_method(), "must be method");
   963         if (m->name() != name) break;
   964         if (m->signature() == signature) return m;
   965       }
   966       // not found
   967 #ifdef ASSERT
   968       int index = linear_search(methods, name, signature);
   969       assert(index == -1, err_msg("binary search should have found entry %d", index));
   970 #endif
   971       return NULL;
   972     } else if (res < 0) {
   973       l = mid + 1;
   974     } else {
   975       h = mid - 1;
   976     }
   977   }
   978 #ifdef ASSERT
   979   int index = linear_search(methods, name, signature);
   980   assert(index == -1, err_msg("binary search should have found entry %d", index));
   981 #endif
   982   return NULL;
   983 }
   985 methodOop instanceKlass::uncached_lookup_method(symbolOop name, symbolOop signature) const {
   986   klassOop klass = as_klassOop();
   987   while (klass != NULL) {
   988     methodOop method = instanceKlass::cast(klass)->find_method(name, signature);
   989     if (method != NULL) return method;
   990     klass = instanceKlass::cast(klass)->super();
   991   }
   992   return NULL;
   993 }
   995 // lookup a method in all the interfaces that this class implements
   996 methodOop instanceKlass::lookup_method_in_all_interfaces(symbolOop name,
   997                                                          symbolOop signature) const {
   998   objArrayOop all_ifs = instanceKlass::cast(as_klassOop())->transitive_interfaces();
   999   int num_ifs = all_ifs->length();
  1000   instanceKlass *ik = NULL;
  1001   for (int i = 0; i < num_ifs; i++) {
  1002     ik = instanceKlass::cast(klassOop(all_ifs->obj_at(i)));
  1003     methodOop m = ik->lookup_method(name, signature);
  1004     if (m != NULL) {
  1005       return m;
  1008   return NULL;
  1011 /* jni_id_for_impl for jfieldIds only */
  1012 JNIid* instanceKlass::jni_id_for_impl(instanceKlassHandle this_oop, int offset) {
  1013   MutexLocker ml(JfieldIdCreation_lock);
  1014   // Retry lookup after we got the lock
  1015   JNIid* probe = this_oop->jni_ids() == NULL ? NULL : this_oop->jni_ids()->find(offset);
  1016   if (probe == NULL) {
  1017     // Slow case, allocate new static field identifier
  1018     probe = new JNIid(this_oop->as_klassOop(), offset, this_oop->jni_ids());
  1019     this_oop->set_jni_ids(probe);
  1021   return probe;
  1025 /* jni_id_for for jfieldIds only */
  1026 JNIid* instanceKlass::jni_id_for(int offset) {
  1027   JNIid* probe = jni_ids() == NULL ? NULL : jni_ids()->find(offset);
  1028   if (probe == NULL) {
  1029     probe = jni_id_for_impl(this->as_klassOop(), offset);
  1031   return probe;
  1035 // Lookup or create a jmethodID.
  1036 // This code is called by the VMThread and JavaThreads so the
  1037 // locking has to be done very carefully to avoid deadlocks
  1038 // and/or other cache consistency problems.
  1039 //
  1040 jmethodID instanceKlass::get_jmethod_id(instanceKlassHandle ik_h, methodHandle method_h) {
  1041   size_t idnum = (size_t)method_h->method_idnum();
  1042   jmethodID* jmeths = ik_h->methods_jmethod_ids_acquire();
  1043   size_t length = 0;
  1044   jmethodID id = NULL;
  1046   // We use a double-check locking idiom here because this cache is
  1047   // performance sensitive. In the normal system, this cache only
  1048   // transitions from NULL to non-NULL which is safe because we use
  1049   // release_set_methods_jmethod_ids() to advertise the new cache.
  1050   // A partially constructed cache should never be seen by a racing
  1051   // thread. We also use release_store_ptr() to save a new jmethodID
  1052   // in the cache so a partially constructed jmethodID should never be
  1053   // seen either. Cache reads of existing jmethodIDs proceed without a
  1054   // lock, but cache writes of a new jmethodID requires uniqueness and
  1055   // creation of the cache itself requires no leaks so a lock is
  1056   // generally acquired in those two cases.
  1057   //
  1058   // If the RedefineClasses() API has been used, then this cache can
  1059   // grow and we'll have transitions from non-NULL to bigger non-NULL.
  1060   // Cache creation requires no leaks and we require safety between all
  1061   // cache accesses and freeing of the old cache so a lock is generally
  1062   // acquired when the RedefineClasses() API has been used.
  1064   if (jmeths != NULL) {
  1065     // the cache already exists
  1066     if (!ik_h->idnum_can_increment()) {
  1067       // the cache can't grow so we can just get the current values
  1068       get_jmethod_id_length_value(jmeths, idnum, &length, &id);
  1069     } else {
  1070       // cache can grow so we have to be more careful
  1071       if (Threads::number_of_threads() == 0 ||
  1072           SafepointSynchronize::is_at_safepoint()) {
  1073         // we're single threaded or at a safepoint - no locking needed
  1074         get_jmethod_id_length_value(jmeths, idnum, &length, &id);
  1075       } else {
  1076         MutexLocker ml(JmethodIdCreation_lock);
  1077         get_jmethod_id_length_value(jmeths, idnum, &length, &id);
  1081   // implied else:
  1082   // we need to allocate a cache so default length and id values are good
  1084   if (jmeths == NULL ||   // no cache yet
  1085       length <= idnum ||  // cache is too short
  1086       id == NULL) {       // cache doesn't contain entry
  1088     // This function can be called by the VMThread so we have to do all
  1089     // things that might block on a safepoint before grabbing the lock.
  1090     // Otherwise, we can deadlock with the VMThread or have a cache
  1091     // consistency issue. These vars keep track of what we might have
  1092     // to free after the lock is dropped.
  1093     jmethodID  to_dealloc_id     = NULL;
  1094     jmethodID* to_dealloc_jmeths = NULL;
  1096     // may not allocate new_jmeths or use it if we allocate it
  1097     jmethodID* new_jmeths = NULL;
  1098     if (length <= idnum) {
  1099       // allocate a new cache that might be used
  1100       size_t size = MAX2(idnum+1, (size_t)ik_h->idnum_allocated_count());
  1101       new_jmeths = NEW_C_HEAP_ARRAY(jmethodID, size+1);
  1102       memset(new_jmeths, 0, (size+1)*sizeof(jmethodID));
  1103       // cache size is stored in element[0], other elements offset by one
  1104       new_jmeths[0] = (jmethodID)size;
  1107     // allocate a new jmethodID that might be used
  1108     jmethodID new_id = NULL;
  1109     if (method_h->is_old() && !method_h->is_obsolete()) {
  1110       // The method passed in is old (but not obsolete), we need to use the current version
  1111       methodOop current_method = ik_h->method_with_idnum((int)idnum);
  1112       assert(current_method != NULL, "old and but not obsolete, so should exist");
  1113       methodHandle current_method_h(current_method == NULL? method_h() : current_method);
  1114       new_id = JNIHandles::make_jmethod_id(current_method_h);
  1115     } else {
  1116       // It is the current version of the method or an obsolete method,
  1117       // use the version passed in
  1118       new_id = JNIHandles::make_jmethod_id(method_h);
  1121     if (Threads::number_of_threads() == 0 ||
  1122         SafepointSynchronize::is_at_safepoint()) {
  1123       // we're single threaded or at a safepoint - no locking needed
  1124       id = get_jmethod_id_fetch_or_update(ik_h, idnum, new_id, new_jmeths,
  1125                                           &to_dealloc_id, &to_dealloc_jmeths);
  1126     } else {
  1127       MutexLocker ml(JmethodIdCreation_lock);
  1128       id = get_jmethod_id_fetch_or_update(ik_h, idnum, new_id, new_jmeths,
  1129                                           &to_dealloc_id, &to_dealloc_jmeths);
  1132     // The lock has been dropped so we can free resources.
  1133     // Free up either the old cache or the new cache if we allocated one.
  1134     if (to_dealloc_jmeths != NULL) {
  1135       FreeHeap(to_dealloc_jmeths);
  1137     // free up the new ID since it wasn't needed
  1138     if (to_dealloc_id != NULL) {
  1139       JNIHandles::destroy_jmethod_id(to_dealloc_id);
  1142   return id;
  1146 // Common code to fetch the jmethodID from the cache or update the
  1147 // cache with the new jmethodID. This function should never do anything
  1148 // that causes the caller to go to a safepoint or we can deadlock with
  1149 // the VMThread or have cache consistency issues.
  1150 //
  1151 jmethodID instanceKlass::get_jmethod_id_fetch_or_update(
  1152             instanceKlassHandle ik_h, size_t idnum, jmethodID new_id,
  1153             jmethodID* new_jmeths, jmethodID* to_dealloc_id_p,
  1154             jmethodID** to_dealloc_jmeths_p) {
  1155   assert(new_id != NULL, "sanity check");
  1156   assert(to_dealloc_id_p != NULL, "sanity check");
  1157   assert(to_dealloc_jmeths_p != NULL, "sanity check");
  1158   assert(Threads::number_of_threads() == 0 ||
  1159          SafepointSynchronize::is_at_safepoint() ||
  1160          JmethodIdCreation_lock->owned_by_self(), "sanity check");
  1162   // reacquire the cache - we are locked, single threaded or at a safepoint
  1163   jmethodID* jmeths = ik_h->methods_jmethod_ids_acquire();
  1164   jmethodID  id     = NULL;
  1165   size_t     length = 0;
  1167   if (jmeths == NULL ||                         // no cache yet
  1168       (length = (size_t)jmeths[0]) <= idnum) {  // cache is too short
  1169     if (jmeths != NULL) {
  1170       // copy any existing entries from the old cache
  1171       for (size_t index = 0; index < length; index++) {
  1172         new_jmeths[index+1] = jmeths[index+1];
  1174       *to_dealloc_jmeths_p = jmeths;  // save old cache for later delete
  1176     ik_h->release_set_methods_jmethod_ids(jmeths = new_jmeths);
  1177   } else {
  1178     // fetch jmethodID (if any) from the existing cache
  1179     id = jmeths[idnum+1];
  1180     *to_dealloc_jmeths_p = new_jmeths;  // save new cache for later delete
  1182   if (id == NULL) {
  1183     // No matching jmethodID in the existing cache or we have a new
  1184     // cache or we just grew the cache. This cache write is done here
  1185     // by the first thread to win the foot race because a jmethodID
  1186     // needs to be unique once it is generally available.
  1187     id = new_id;
  1189     // The jmethodID cache can be read while unlocked so we have to
  1190     // make sure the new jmethodID is complete before installing it
  1191     // in the cache.
  1192     OrderAccess::release_store_ptr(&jmeths[idnum+1], id);
  1193   } else {
  1194     *to_dealloc_id_p = new_id; // save new id for later delete
  1196   return id;
  1200 // Common code to get the jmethodID cache length and the jmethodID
  1201 // value at index idnum if there is one.
  1202 //
  1203 void instanceKlass::get_jmethod_id_length_value(jmethodID* cache,
  1204        size_t idnum, size_t *length_p, jmethodID* id_p) {
  1205   assert(cache != NULL, "sanity check");
  1206   assert(length_p != NULL, "sanity check");
  1207   assert(id_p != NULL, "sanity check");
  1209   // cache size is stored in element[0], other elements offset by one
  1210   *length_p = (size_t)cache[0];
  1211   if (*length_p <= idnum) {  // cache is too short
  1212     *id_p = NULL;
  1213   } else {
  1214     *id_p = cache[idnum+1];  // fetch jmethodID (if any)
  1219 // Lookup a jmethodID, NULL if not found.  Do no blocking, no allocations, no handles
  1220 jmethodID instanceKlass::jmethod_id_or_null(methodOop method) {
  1221   size_t idnum = (size_t)method->method_idnum();
  1222   jmethodID* jmeths = methods_jmethod_ids_acquire();
  1223   size_t length;                                // length assigned as debugging crumb
  1224   jmethodID id = NULL;
  1225   if (jmeths != NULL &&                         // If there is a cache
  1226       (length = (size_t)jmeths[0]) > idnum) {   // and if it is long enough,
  1227     id = jmeths[idnum+1];                       // Look up the id (may be NULL)
  1229   return id;
  1233 // Cache an itable index
  1234 void instanceKlass::set_cached_itable_index(size_t idnum, int index) {
  1235   int* indices = methods_cached_itable_indices_acquire();
  1236   int* to_dealloc_indices = NULL;
  1238   // We use a double-check locking idiom here because this cache is
  1239   // performance sensitive. In the normal system, this cache only
  1240   // transitions from NULL to non-NULL which is safe because we use
  1241   // release_set_methods_cached_itable_indices() to advertise the
  1242   // new cache. A partially constructed cache should never be seen
  1243   // by a racing thread. Cache reads and writes proceed without a
  1244   // lock, but creation of the cache itself requires no leaks so a
  1245   // lock is generally acquired in that case.
  1246   //
  1247   // If the RedefineClasses() API has been used, then this cache can
  1248   // grow and we'll have transitions from non-NULL to bigger non-NULL.
  1249   // Cache creation requires no leaks and we require safety between all
  1250   // cache accesses and freeing of the old cache so a lock is generally
  1251   // acquired when the RedefineClasses() API has been used.
  1253   if (indices == NULL || idnum_can_increment()) {
  1254     // we need a cache or the cache can grow
  1255     MutexLocker ml(JNICachedItableIndex_lock);
  1256     // reacquire the cache to see if another thread already did the work
  1257     indices = methods_cached_itable_indices_acquire();
  1258     size_t length = 0;
  1259     // cache size is stored in element[0], other elements offset by one
  1260     if (indices == NULL || (length = (size_t)indices[0]) <= idnum) {
  1261       size_t size = MAX2(idnum+1, (size_t)idnum_allocated_count());
  1262       int* new_indices = NEW_C_HEAP_ARRAY(int, size+1);
  1263       new_indices[0] = (int)size;
  1264       // copy any existing entries
  1265       size_t i;
  1266       for (i = 0; i < length; i++) {
  1267         new_indices[i+1] = indices[i+1];
  1269       // Set all the rest to -1
  1270       for (i = length; i < size; i++) {
  1271         new_indices[i+1] = -1;
  1273       if (indices != NULL) {
  1274         // We have an old cache to delete so save it for after we
  1275         // drop the lock.
  1276         to_dealloc_indices = indices;
  1278       release_set_methods_cached_itable_indices(indices = new_indices);
  1281     if (idnum_can_increment()) {
  1282       // this cache can grow so we have to write to it safely
  1283       indices[idnum+1] = index;
  1285   } else {
  1286     CHECK_UNHANDLED_OOPS_ONLY(Thread::current()->clear_unhandled_oops());
  1289   if (!idnum_can_increment()) {
  1290     // The cache cannot grow and this JNI itable index value does not
  1291     // have to be unique like a jmethodID. If there is a race to set it,
  1292     // it doesn't matter.
  1293     indices[idnum+1] = index;
  1296   if (to_dealloc_indices != NULL) {
  1297     // we allocated a new cache so free the old one
  1298     FreeHeap(to_dealloc_indices);
  1303 // Retrieve a cached itable index
  1304 int instanceKlass::cached_itable_index(size_t idnum) {
  1305   int* indices = methods_cached_itable_indices_acquire();
  1306   if (indices != NULL && ((size_t)indices[0]) > idnum) {
  1307      // indices exist and are long enough, retrieve possible cached
  1308     return indices[idnum+1];
  1310   return -1;
  1314 //
  1315 // nmethodBucket is used to record dependent nmethods for
  1316 // deoptimization.  nmethod dependencies are actually <klass, method>
  1317 // pairs but we really only care about the klass part for purposes of
  1318 // finding nmethods which might need to be deoptimized.  Instead of
  1319 // recording the method, a count of how many times a particular nmethod
  1320 // was recorded is kept.  This ensures that any recording errors are
  1321 // noticed since an nmethod should be removed as many times are it's
  1322 // added.
  1323 //
  1324 class nmethodBucket {
  1325  private:
  1326   nmethod*       _nmethod;
  1327   int            _count;
  1328   nmethodBucket* _next;
  1330  public:
  1331   nmethodBucket(nmethod* nmethod, nmethodBucket* next) {
  1332     _nmethod = nmethod;
  1333     _next = next;
  1334     _count = 1;
  1336   int count()                             { return _count; }
  1337   int increment()                         { _count += 1; return _count; }
  1338   int decrement()                         { _count -= 1; assert(_count >= 0, "don't underflow"); return _count; }
  1339   nmethodBucket* next()                   { return _next; }
  1340   void set_next(nmethodBucket* b)         { _next = b; }
  1341   nmethod* get_nmethod()                  { return _nmethod; }
  1342 };
  1345 //
  1346 // Walk the list of dependent nmethods searching for nmethods which
  1347 // are dependent on the klassOop that was passed in and mark them for
  1348 // deoptimization.  Returns the number of nmethods found.
  1349 //
  1350 int instanceKlass::mark_dependent_nmethods(DepChange& changes) {
  1351   assert_locked_or_safepoint(CodeCache_lock);
  1352   int found = 0;
  1353   nmethodBucket* b = _dependencies;
  1354   while (b != NULL) {
  1355     nmethod* nm = b->get_nmethod();
  1356     // since dependencies aren't removed until an nmethod becomes a zombie,
  1357     // the dependency list may contain nmethods which aren't alive.
  1358     if (nm->is_alive() && !nm->is_marked_for_deoptimization() && nm->check_dependency_on(changes)) {
  1359       if (TraceDependencies) {
  1360         ResourceMark rm;
  1361         tty->print_cr("Marked for deoptimization");
  1362         tty->print_cr("  context = %s", this->external_name());
  1363         changes.print();
  1364         nm->print();
  1365         nm->print_dependencies();
  1367       nm->mark_for_deoptimization();
  1368       found++;
  1370     b = b->next();
  1372   return found;
  1376 //
  1377 // Add an nmethodBucket to the list of dependencies for this nmethod.
  1378 // It's possible that an nmethod has multiple dependencies on this klass
  1379 // so a count is kept for each bucket to guarantee that creation and
  1380 // deletion of dependencies is consistent.
  1381 //
  1382 void instanceKlass::add_dependent_nmethod(nmethod* nm) {
  1383   assert_locked_or_safepoint(CodeCache_lock);
  1384   nmethodBucket* b = _dependencies;
  1385   nmethodBucket* last = NULL;
  1386   while (b != NULL) {
  1387     if (nm == b->get_nmethod()) {
  1388       b->increment();
  1389       return;
  1391     b = b->next();
  1393   _dependencies = new nmethodBucket(nm, _dependencies);
  1397 //
  1398 // Decrement count of the nmethod in the dependency list and remove
  1399 // the bucket competely when the count goes to 0.  This method must
  1400 // find a corresponding bucket otherwise there's a bug in the
  1401 // recording of dependecies.
  1402 //
  1403 void instanceKlass::remove_dependent_nmethod(nmethod* nm) {
  1404   assert_locked_or_safepoint(CodeCache_lock);
  1405   nmethodBucket* b = _dependencies;
  1406   nmethodBucket* last = NULL;
  1407   while (b != NULL) {
  1408     if (nm == b->get_nmethod()) {
  1409       if (b->decrement() == 0) {
  1410         if (last == NULL) {
  1411           _dependencies = b->next();
  1412         } else {
  1413           last->set_next(b->next());
  1415         delete b;
  1417       return;
  1419     last = b;
  1420     b = b->next();
  1422 #ifdef ASSERT
  1423   tty->print_cr("### %s can't find dependent nmethod:", this->external_name());
  1424   nm->print();
  1425 #endif // ASSERT
  1426   ShouldNotReachHere();
  1430 #ifndef PRODUCT
  1431 void instanceKlass::print_dependent_nmethods(bool verbose) {
  1432   nmethodBucket* b = _dependencies;
  1433   int idx = 0;
  1434   while (b != NULL) {
  1435     nmethod* nm = b->get_nmethod();
  1436     tty->print("[%d] count=%d { ", idx++, b->count());
  1437     if (!verbose) {
  1438       nm->print_on(tty, "nmethod");
  1439       tty->print_cr(" } ");
  1440     } else {
  1441       nm->print();
  1442       nm->print_dependencies();
  1443       tty->print_cr("--- } ");
  1445     b = b->next();
  1450 bool instanceKlass::is_dependent_nmethod(nmethod* nm) {
  1451   nmethodBucket* b = _dependencies;
  1452   while (b != NULL) {
  1453     if (nm == b->get_nmethod()) {
  1454       return true;
  1456     b = b->next();
  1458   return false;
  1460 #endif //PRODUCT
  1463 #ifdef ASSERT
  1464 template <class T> void assert_is_in(T *p) {
  1465   T heap_oop = oopDesc::load_heap_oop(p);
  1466   if (!oopDesc::is_null(heap_oop)) {
  1467     oop o = oopDesc::decode_heap_oop_not_null(heap_oop);
  1468     assert(Universe::heap()->is_in(o), "should be in heap");
  1471 template <class T> void assert_is_in_closed_subset(T *p) {
  1472   T heap_oop = oopDesc::load_heap_oop(p);
  1473   if (!oopDesc::is_null(heap_oop)) {
  1474     oop o = oopDesc::decode_heap_oop_not_null(heap_oop);
  1475     assert(Universe::heap()->is_in_closed_subset(o), "should be in closed");
  1478 template <class T> void assert_is_in_reserved(T *p) {
  1479   T heap_oop = oopDesc::load_heap_oop(p);
  1480   if (!oopDesc::is_null(heap_oop)) {
  1481     oop o = oopDesc::decode_heap_oop_not_null(heap_oop);
  1482     assert(Universe::heap()->is_in_reserved(o), "should be in reserved");
  1485 template <class T> void assert_nothing(T *p) {}
  1487 #else
  1488 template <class T> void assert_is_in(T *p) {}
  1489 template <class T> void assert_is_in_closed_subset(T *p) {}
  1490 template <class T> void assert_is_in_reserved(T *p) {}
  1491 template <class T> void assert_nothing(T *p) {}
  1492 #endif // ASSERT
  1494 //
  1495 // Macros that iterate over areas of oops which are specialized on type of
  1496 // oop pointer either narrow or wide, depending on UseCompressedOops
  1497 //
  1498 // Parameters are:
  1499 //   T         - type of oop to point to (either oop or narrowOop)
  1500 //   start_p   - starting pointer for region to iterate over
  1501 //   count     - number of oops or narrowOops to iterate over
  1502 //   do_oop    - action to perform on each oop (it's arbitrary C code which
  1503 //               makes it more efficient to put in a macro rather than making
  1504 //               it a template function)
  1505 //   assert_fn - assert function which is template function because performance
  1506 //               doesn't matter when enabled.
  1507 #define InstanceKlass_SPECIALIZED_OOP_ITERATE( \
  1508   T, start_p, count, do_oop,                \
  1509   assert_fn)                                \
  1510 {                                           \
  1511   T* p         = (T*)(start_p);             \
  1512   T* const end = p + (count);               \
  1513   while (p < end) {                         \
  1514     (assert_fn)(p);                         \
  1515     do_oop;                                 \
  1516     ++p;                                    \
  1517   }                                         \
  1520 #define InstanceKlass_SPECIALIZED_OOP_REVERSE_ITERATE( \
  1521   T, start_p, count, do_oop,                \
  1522   assert_fn)                                \
  1523 {                                           \
  1524   T* const start = (T*)(start_p);           \
  1525   T*       p     = start + (count);         \
  1526   while (start < p) {                       \
  1527     --p;                                    \
  1528     (assert_fn)(p);                         \
  1529     do_oop;                                 \
  1530   }                                         \
  1533 #define InstanceKlass_SPECIALIZED_BOUNDED_OOP_ITERATE( \
  1534   T, start_p, count, low, high,             \
  1535   do_oop, assert_fn)                        \
  1536 {                                           \
  1537   T* const l = (T*)(low);                   \
  1538   T* const h = (T*)(high);                  \
  1539   assert(mask_bits((intptr_t)l, sizeof(T)-1) == 0 && \
  1540          mask_bits((intptr_t)h, sizeof(T)-1) == 0,   \
  1541          "bounded region must be properly aligned"); \
  1542   T* p       = (T*)(start_p);               \
  1543   T* end     = p + (count);                 \
  1544   if (p < l) p = l;                         \
  1545   if (end > h) end = h;                     \
  1546   while (p < end) {                         \
  1547     (assert_fn)(p);                         \
  1548     do_oop;                                 \
  1549     ++p;                                    \
  1550   }                                         \
  1554 // The following macros call specialized macros, passing either oop or
  1555 // narrowOop as the specialization type.  These test the UseCompressedOops
  1556 // flag.
  1557 #define InstanceKlass_OOP_ITERATE(start_p, count,    \
  1558                                   do_oop, assert_fn) \
  1559 {                                                    \
  1560   if (UseCompressedOops) {                           \
  1561     InstanceKlass_SPECIALIZED_OOP_ITERATE(narrowOop, \
  1562       start_p, count,                                \
  1563       do_oop, assert_fn)                             \
  1564   } else {                                           \
  1565     InstanceKlass_SPECIALIZED_OOP_ITERATE(oop,       \
  1566       start_p, count,                                \
  1567       do_oop, assert_fn)                             \
  1568   }                                                  \
  1571 #define InstanceKlass_BOUNDED_OOP_ITERATE(start_p, count, low, high,    \
  1572                                           do_oop, assert_fn) \
  1573 {                                                            \
  1574   if (UseCompressedOops) {                                   \
  1575     InstanceKlass_SPECIALIZED_BOUNDED_OOP_ITERATE(narrowOop, \
  1576       start_p, count,                                        \
  1577       low, high,                                             \
  1578       do_oop, assert_fn)                                     \
  1579   } else {                                                   \
  1580     InstanceKlass_SPECIALIZED_BOUNDED_OOP_ITERATE(oop,       \
  1581       start_p, count,                                        \
  1582       low, high,                                             \
  1583       do_oop, assert_fn)                                     \
  1584   }                                                          \
  1587 #define InstanceKlass_OOP_MAP_ITERATE(obj, do_oop, assert_fn)            \
  1588 {                                                                        \
  1589   /* Compute oopmap block range. The common case                         \
  1590      is nonstatic_oop_map_size == 1. */                                  \
  1591   OopMapBlock* map           = start_of_nonstatic_oop_maps();            \
  1592   OopMapBlock* const end_map = map + nonstatic_oop_map_count();          \
  1593   if (UseCompressedOops) {                                               \
  1594     while (map < end_map) {                                              \
  1595       InstanceKlass_SPECIALIZED_OOP_ITERATE(narrowOop,                   \
  1596         obj->obj_field_addr<narrowOop>(map->offset()), map->count(),     \
  1597         do_oop, assert_fn)                                               \
  1598       ++map;                                                             \
  1599     }                                                                    \
  1600   } else {                                                               \
  1601     while (map < end_map) {                                              \
  1602       InstanceKlass_SPECIALIZED_OOP_ITERATE(oop,                         \
  1603         obj->obj_field_addr<oop>(map->offset()), map->count(),           \
  1604         do_oop, assert_fn)                                               \
  1605       ++map;                                                             \
  1606     }                                                                    \
  1607   }                                                                      \
  1610 #define InstanceKlass_OOP_MAP_REVERSE_ITERATE(obj, do_oop, assert_fn)    \
  1611 {                                                                        \
  1612   OopMapBlock* const start_map = start_of_nonstatic_oop_maps();          \
  1613   OopMapBlock* map             = start_map + nonstatic_oop_map_count();  \
  1614   if (UseCompressedOops) {                                               \
  1615     while (start_map < map) {                                            \
  1616       --map;                                                             \
  1617       InstanceKlass_SPECIALIZED_OOP_REVERSE_ITERATE(narrowOop,           \
  1618         obj->obj_field_addr<narrowOop>(map->offset()), map->count(),     \
  1619         do_oop, assert_fn)                                               \
  1620     }                                                                    \
  1621   } else {                                                               \
  1622     while (start_map < map) {                                            \
  1623       --map;                                                             \
  1624       InstanceKlass_SPECIALIZED_OOP_REVERSE_ITERATE(oop,                 \
  1625         obj->obj_field_addr<oop>(map->offset()), map->count(),           \
  1626         do_oop, assert_fn)                                               \
  1627     }                                                                    \
  1628   }                                                                      \
  1631 #define InstanceKlass_BOUNDED_OOP_MAP_ITERATE(obj, low, high, do_oop,    \
  1632                                               assert_fn)                 \
  1633 {                                                                        \
  1634   /* Compute oopmap block range. The common case is                      \
  1635      nonstatic_oop_map_size == 1, so we accept the                       \
  1636      usually non-existent extra overhead of examining                    \
  1637      all the maps. */                                                    \
  1638   OopMapBlock* map           = start_of_nonstatic_oop_maps();            \
  1639   OopMapBlock* const end_map = map + nonstatic_oop_map_count();          \
  1640   if (UseCompressedOops) {                                               \
  1641     while (map < end_map) {                                              \
  1642       InstanceKlass_SPECIALIZED_BOUNDED_OOP_ITERATE(narrowOop,           \
  1643         obj->obj_field_addr<narrowOop>(map->offset()), map->count(),     \
  1644         low, high,                                                       \
  1645         do_oop, assert_fn)                                               \
  1646       ++map;                                                             \
  1647     }                                                                    \
  1648   } else {                                                               \
  1649     while (map < end_map) {                                              \
  1650       InstanceKlass_SPECIALIZED_BOUNDED_OOP_ITERATE(oop,                 \
  1651         obj->obj_field_addr<oop>(map->offset()), map->count(),           \
  1652         low, high,                                                       \
  1653         do_oop, assert_fn)                                               \
  1654       ++map;                                                             \
  1655     }                                                                    \
  1656   }                                                                      \
  1659 void instanceKlass::follow_static_fields() {
  1660   InstanceKlass_OOP_ITERATE( \
  1661     start_of_static_fields(), static_oop_field_size(), \
  1662     MarkSweep::mark_and_push(p), \
  1663     assert_is_in_closed_subset)
  1666 #ifndef SERIALGC
  1667 void instanceKlass::follow_static_fields(ParCompactionManager* cm) {
  1668   InstanceKlass_OOP_ITERATE( \
  1669     start_of_static_fields(), static_oop_field_size(), \
  1670     PSParallelCompact::mark_and_push(cm, p), \
  1671     assert_is_in)
  1673 #endif // SERIALGC
  1675 void instanceKlass::adjust_static_fields() {
  1676   InstanceKlass_OOP_ITERATE( \
  1677     start_of_static_fields(), static_oop_field_size(), \
  1678     MarkSweep::adjust_pointer(p), \
  1679     assert_nothing)
  1682 #ifndef SERIALGC
  1683 void instanceKlass::update_static_fields() {
  1684   InstanceKlass_OOP_ITERATE( \
  1685     start_of_static_fields(), static_oop_field_size(), \
  1686     PSParallelCompact::adjust_pointer(p), \
  1687     assert_nothing)
  1690 void instanceKlass::update_static_fields(HeapWord* beg_addr, HeapWord* end_addr) {
  1691   InstanceKlass_BOUNDED_OOP_ITERATE( \
  1692     start_of_static_fields(), static_oop_field_size(), \
  1693     beg_addr, end_addr, \
  1694     PSParallelCompact::adjust_pointer(p), \
  1695     assert_nothing )
  1697 #endif // SERIALGC
  1699 void instanceKlass::oop_follow_contents(oop obj) {
  1700   assert(obj != NULL, "can't follow the content of NULL object");
  1701   obj->follow_header();
  1702   InstanceKlass_OOP_MAP_ITERATE( \
  1703     obj, \
  1704     MarkSweep::mark_and_push(p), \
  1705     assert_is_in_closed_subset)
  1708 #ifndef SERIALGC
  1709 void instanceKlass::oop_follow_contents(ParCompactionManager* cm,
  1710                                         oop obj) {
  1711   assert(obj != NULL, "can't follow the content of NULL object");
  1712   obj->follow_header(cm);
  1713   InstanceKlass_OOP_MAP_ITERATE( \
  1714     obj, \
  1715     PSParallelCompact::mark_and_push(cm, p), \
  1716     assert_is_in)
  1718 #endif // SERIALGC
  1720 // closure's do_header() method dicates whether the given closure should be
  1721 // applied to the klass ptr in the object header.
  1723 #define InstanceKlass_OOP_OOP_ITERATE_DEFN(OopClosureType, nv_suffix)        \
  1725 int instanceKlass::oop_oop_iterate##nv_suffix(oop obj, OopClosureType* closure) { \
  1726   SpecializationStats::record_iterate_call##nv_suffix(SpecializationStats::ik);\
  1727   /* header */                                                          \
  1728   if (closure->do_header()) {                                           \
  1729     obj->oop_iterate_header(closure);                                   \
  1730   }                                                                     \
  1731   InstanceKlass_OOP_MAP_ITERATE(                                        \
  1732     obj,                                                                \
  1733     SpecializationStats::                                               \
  1734       record_do_oop_call##nv_suffix(SpecializationStats::ik);           \
  1735     (closure)->do_oop##nv_suffix(p),                                    \
  1736     assert_is_in_closed_subset)                                         \
  1737   return size_helper();                                                 \
  1740 #ifndef SERIALGC
  1741 #define InstanceKlass_OOP_OOP_ITERATE_BACKWARDS_DEFN(OopClosureType, nv_suffix) \
  1743 int instanceKlass::oop_oop_iterate_backwards##nv_suffix(oop obj,                \
  1744                                               OopClosureType* closure) {        \
  1745   SpecializationStats::record_iterate_call##nv_suffix(SpecializationStats::ik); \
  1746   /* header */                                                                  \
  1747   if (closure->do_header()) {                                                   \
  1748     obj->oop_iterate_header(closure);                                           \
  1749   }                                                                             \
  1750   /* instance variables */                                                      \
  1751   InstanceKlass_OOP_MAP_REVERSE_ITERATE(                                        \
  1752     obj,                                                                        \
  1753     SpecializationStats::record_do_oop_call##nv_suffix(SpecializationStats::ik);\
  1754     (closure)->do_oop##nv_suffix(p),                                            \
  1755     assert_is_in_closed_subset)                                                 \
  1756    return size_helper();                                                        \
  1758 #endif // !SERIALGC
  1760 #define InstanceKlass_OOP_OOP_ITERATE_DEFN_m(OopClosureType, nv_suffix) \
  1762 int instanceKlass::oop_oop_iterate##nv_suffix##_m(oop obj,              \
  1763                                                   OopClosureType* closure, \
  1764                                                   MemRegion mr) {          \
  1765   SpecializationStats::record_iterate_call##nv_suffix(SpecializationStats::ik);\
  1766   if (closure->do_header()) {                                            \
  1767     obj->oop_iterate_header(closure, mr);                                \
  1768   }                                                                      \
  1769   InstanceKlass_BOUNDED_OOP_MAP_ITERATE(                                 \
  1770     obj, mr.start(), mr.end(),                                           \
  1771     (closure)->do_oop##nv_suffix(p),                                     \
  1772     assert_is_in_closed_subset)                                          \
  1773   return size_helper();                                                  \
  1776 ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceKlass_OOP_OOP_ITERATE_DEFN)
  1777 ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceKlass_OOP_OOP_ITERATE_DEFN)
  1778 ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceKlass_OOP_OOP_ITERATE_DEFN_m)
  1779 ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceKlass_OOP_OOP_ITERATE_DEFN_m)
  1780 #ifndef SERIALGC
  1781 ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceKlass_OOP_OOP_ITERATE_BACKWARDS_DEFN)
  1782 ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceKlass_OOP_OOP_ITERATE_BACKWARDS_DEFN)
  1783 #endif // !SERIALGC
  1785 void instanceKlass::iterate_static_fields(OopClosure* closure) {
  1786     InstanceKlass_OOP_ITERATE( \
  1787       start_of_static_fields(), static_oop_field_size(), \
  1788       closure->do_oop(p), \
  1789       assert_is_in_reserved)
  1792 void instanceKlass::iterate_static_fields(OopClosure* closure,
  1793                                           MemRegion mr) {
  1794   InstanceKlass_BOUNDED_OOP_ITERATE( \
  1795     start_of_static_fields(), static_oop_field_size(), \
  1796     mr.start(), mr.end(), \
  1797     (closure)->do_oop_v(p), \
  1798     assert_is_in_closed_subset)
  1801 int instanceKlass::oop_adjust_pointers(oop obj) {
  1802   int size = size_helper();
  1803   InstanceKlass_OOP_MAP_ITERATE( \
  1804     obj, \
  1805     MarkSweep::adjust_pointer(p), \
  1806     assert_is_in)
  1807   obj->adjust_header();
  1808   return size;
  1811 #ifndef SERIALGC
  1812 void instanceKlass::oop_push_contents(PSPromotionManager* pm, oop obj) {
  1813   InstanceKlass_OOP_MAP_REVERSE_ITERATE( \
  1814     obj, \
  1815     if (PSScavenge::should_scavenge(p)) { \
  1816       pm->claim_or_forward_depth(p); \
  1817     }, \
  1818     assert_nothing )
  1821 int instanceKlass::oop_update_pointers(ParCompactionManager* cm, oop obj) {
  1822   InstanceKlass_OOP_MAP_ITERATE( \
  1823     obj, \
  1824     PSParallelCompact::adjust_pointer(p), \
  1825     assert_nothing)
  1826   return size_helper();
  1829 int instanceKlass::oop_update_pointers(ParCompactionManager* cm, oop obj,
  1830                                        HeapWord* beg_addr, HeapWord* end_addr) {
  1831   InstanceKlass_BOUNDED_OOP_MAP_ITERATE( \
  1832     obj, beg_addr, end_addr, \
  1833     PSParallelCompact::adjust_pointer(p), \
  1834     assert_nothing)
  1835   return size_helper();
  1838 void instanceKlass::push_static_fields(PSPromotionManager* pm) {
  1839   InstanceKlass_OOP_ITERATE( \
  1840     start_of_static_fields(), static_oop_field_size(), \
  1841     if (PSScavenge::should_scavenge(p)) { \
  1842       pm->claim_or_forward_depth(p); \
  1843     }, \
  1844     assert_nothing )
  1847 void instanceKlass::copy_static_fields(ParCompactionManager* cm) {
  1848   InstanceKlass_OOP_ITERATE( \
  1849     start_of_static_fields(), static_oop_field_size(), \
  1850     PSParallelCompact::adjust_pointer(p), \
  1851     assert_is_in)
  1853 #endif // SERIALGC
  1855 // This klass is alive but the implementor link is not followed/updated.
  1856 // Subklass and sibling links are handled by Klass::follow_weak_klass_links
  1858 void instanceKlass::follow_weak_klass_links(
  1859   BoolObjectClosure* is_alive, OopClosure* keep_alive) {
  1860   assert(is_alive->do_object_b(as_klassOop()), "this oop should be live");
  1861   if (ClassUnloading) {
  1862     for (int i = 0; i < implementors_limit; i++) {
  1863       klassOop impl = _implementors[i];
  1864       if (impl == NULL)  break;  // no more in the list
  1865       if (!is_alive->do_object_b(impl)) {
  1866         // remove this guy from the list by overwriting him with the tail
  1867         int lasti = --_nof_implementors;
  1868         assert(lasti >= i && lasti < implementors_limit, "just checking");
  1869         _implementors[i] = _implementors[lasti];
  1870         _implementors[lasti] = NULL;
  1871         --i; // rerun the loop at this index
  1874   } else {
  1875     for (int i = 0; i < implementors_limit; i++) {
  1876       keep_alive->do_oop(&adr_implementors()[i]);
  1879   Klass::follow_weak_klass_links(is_alive, keep_alive);
  1882 void instanceKlass::remove_unshareable_info() {
  1883   Klass::remove_unshareable_info();
  1884   init_implementor();
  1887 static void clear_all_breakpoints(methodOop m) {
  1888   m->clear_all_breakpoints();
  1891 void instanceKlass::release_C_heap_structures() {
  1892   // Deallocate oop map cache
  1893   if (_oop_map_cache != NULL) {
  1894     delete _oop_map_cache;
  1895     _oop_map_cache = NULL;
  1898   // Deallocate JNI identifiers for jfieldIDs
  1899   JNIid::deallocate(jni_ids());
  1900   set_jni_ids(NULL);
  1902   jmethodID* jmeths = methods_jmethod_ids_acquire();
  1903   if (jmeths != (jmethodID*)NULL) {
  1904     release_set_methods_jmethod_ids(NULL);
  1905     FreeHeap(jmeths);
  1908   int* indices = methods_cached_itable_indices_acquire();
  1909   if (indices != (int*)NULL) {
  1910     release_set_methods_cached_itable_indices(NULL);
  1911     FreeHeap(indices);
  1914   // release dependencies
  1915   nmethodBucket* b = _dependencies;
  1916   _dependencies = NULL;
  1917   while (b != NULL) {
  1918     nmethodBucket* next = b->next();
  1919     delete b;
  1920     b = next;
  1923   // Deallocate breakpoint records
  1924   if (breakpoints() != 0x0) {
  1925     methods_do(clear_all_breakpoints);
  1926     assert(breakpoints() == 0x0, "should have cleared breakpoints");
  1929   // deallocate information about previous versions
  1930   if (_previous_versions != NULL) {
  1931     for (int i = _previous_versions->length() - 1; i >= 0; i--) {
  1932       PreviousVersionNode * pv_node = _previous_versions->at(i);
  1933       delete pv_node;
  1935     delete _previous_versions;
  1936     _previous_versions = NULL;
  1939   // deallocate the cached class file
  1940   if (_cached_class_file_bytes != NULL) {
  1941     os::free(_cached_class_file_bytes);
  1942     _cached_class_file_bytes = NULL;
  1943     _cached_class_file_len = 0;
  1947 const char* instanceKlass::signature_name() const {
  1948   const char* src = (const char*) (name()->as_C_string());
  1949   const int src_length = (int)strlen(src);
  1950   char* dest = NEW_RESOURCE_ARRAY(char, src_length + 3);
  1951   int src_index = 0;
  1952   int dest_index = 0;
  1953   dest[dest_index++] = 'L';
  1954   while (src_index < src_length) {
  1955     dest[dest_index++] = src[src_index++];
  1957   dest[dest_index++] = ';';
  1958   dest[dest_index] = '\0';
  1959   return dest;
  1962 // different verisons of is_same_class_package
  1963 bool instanceKlass::is_same_class_package(klassOop class2) {
  1964   klassOop class1 = as_klassOop();
  1965   oop classloader1 = instanceKlass::cast(class1)->class_loader();
  1966   symbolOop classname1 = Klass::cast(class1)->name();
  1968   if (Klass::cast(class2)->oop_is_objArray()) {
  1969     class2 = objArrayKlass::cast(class2)->bottom_klass();
  1971   oop classloader2;
  1972   if (Klass::cast(class2)->oop_is_instance()) {
  1973     classloader2 = instanceKlass::cast(class2)->class_loader();
  1974   } else {
  1975     assert(Klass::cast(class2)->oop_is_typeArray(), "should be type array");
  1976     classloader2 = NULL;
  1978   symbolOop classname2 = Klass::cast(class2)->name();
  1980   return instanceKlass::is_same_class_package(classloader1, classname1,
  1981                                               classloader2, classname2);
  1984 bool instanceKlass::is_same_class_package(oop classloader2, symbolOop classname2) {
  1985   klassOop class1 = as_klassOop();
  1986   oop classloader1 = instanceKlass::cast(class1)->class_loader();
  1987   symbolOop classname1 = Klass::cast(class1)->name();
  1989   return instanceKlass::is_same_class_package(classloader1, classname1,
  1990                                               classloader2, classname2);
  1993 // return true if two classes are in the same package, classloader
  1994 // and classname information is enough to determine a class's package
  1995 bool instanceKlass::is_same_class_package(oop class_loader1, symbolOop class_name1,
  1996                                           oop class_loader2, symbolOop class_name2) {
  1997   if (class_loader1 != class_loader2) {
  1998     return false;
  1999   } else if (class_name1 == class_name2) {
  2000     return true;                // skip painful bytewise comparison
  2001   } else {
  2002     ResourceMark rm;
  2004     // The symbolOop's are in UTF8 encoding. Since we only need to check explicitly
  2005     // for ASCII characters ('/', 'L', '['), we can keep them in UTF8 encoding.
  2006     // Otherwise, we just compare jbyte values between the strings.
  2007     jbyte *name1 = class_name1->base();
  2008     jbyte *name2 = class_name2->base();
  2010     jbyte *last_slash1 = UTF8::strrchr(name1, class_name1->utf8_length(), '/');
  2011     jbyte *last_slash2 = UTF8::strrchr(name2, class_name2->utf8_length(), '/');
  2013     if ((last_slash1 == NULL) || (last_slash2 == NULL)) {
  2014       // One of the two doesn't have a package.  Only return true
  2015       // if the other one also doesn't have a package.
  2016       return last_slash1 == last_slash2;
  2017     } else {
  2018       // Skip over '['s
  2019       if (*name1 == '[') {
  2020         do {
  2021           name1++;
  2022         } while (*name1 == '[');
  2023         if (*name1 != 'L') {
  2024           // Something is terribly wrong.  Shouldn't be here.
  2025           return false;
  2028       if (*name2 == '[') {
  2029         do {
  2030           name2++;
  2031         } while (*name2 == '[');
  2032         if (*name2 != 'L') {
  2033           // Something is terribly wrong.  Shouldn't be here.
  2034           return false;
  2038       // Check that package part is identical
  2039       int length1 = last_slash1 - name1;
  2040       int length2 = last_slash2 - name2;
  2042       return UTF8::equal(name1, length1, name2, length2);
  2047 // Returns true iff super_method can be overridden by a method in targetclassname
  2048 // See JSL 3rd edition 8.4.6.1
  2049 // Assumes name-signature match
  2050 // "this" is instanceKlass of super_method which must exist
  2051 // note that the instanceKlass of the method in the targetclassname has not always been created yet
  2052 bool instanceKlass::is_override(methodHandle super_method, Handle targetclassloader, symbolHandle targetclassname, TRAPS) {
  2053    // Private methods can not be overridden
  2054    if (super_method->is_private()) {
  2055      return false;
  2057    // If super method is accessible, then override
  2058    if ((super_method->is_protected()) ||
  2059        (super_method->is_public())) {
  2060      return true;
  2062    // Package-private methods are not inherited outside of package
  2063    assert(super_method->is_package_private(), "must be package private");
  2064    return(is_same_class_package(targetclassloader(), targetclassname()));
  2067 /* defined for now in jvm.cpp, for historical reasons *--
  2068 klassOop instanceKlass::compute_enclosing_class_impl(instanceKlassHandle self,
  2069                                                      symbolOop& simple_name_result, TRAPS) {
  2070   ...
  2072 */
  2074 // tell if two classes have the same enclosing class (at package level)
  2075 bool instanceKlass::is_same_package_member_impl(instanceKlassHandle class1,
  2076                                                 klassOop class2_oop, TRAPS) {
  2077   if (class2_oop == class1->as_klassOop())          return true;
  2078   if (!Klass::cast(class2_oop)->oop_is_instance())  return false;
  2079   instanceKlassHandle class2(THREAD, class2_oop);
  2081   // must be in same package before we try anything else
  2082   if (!class1->is_same_class_package(class2->class_loader(), class2->name()))
  2083     return false;
  2085   // As long as there is an outer1.getEnclosingClass,
  2086   // shift the search outward.
  2087   instanceKlassHandle outer1 = class1;
  2088   for (;;) {
  2089     // As we walk along, look for equalities between outer1 and class2.
  2090     // Eventually, the walks will terminate as outer1 stops
  2091     // at the top-level class around the original class.
  2092     bool ignore_inner_is_member;
  2093     klassOop next = outer1->compute_enclosing_class(&ignore_inner_is_member,
  2094                                                     CHECK_false);
  2095     if (next == NULL)  break;
  2096     if (next == class2())  return true;
  2097     outer1 = instanceKlassHandle(THREAD, next);
  2100   // Now do the same for class2.
  2101   instanceKlassHandle outer2 = class2;
  2102   for (;;) {
  2103     bool ignore_inner_is_member;
  2104     klassOop next = outer2->compute_enclosing_class(&ignore_inner_is_member,
  2105                                                     CHECK_false);
  2106     if (next == NULL)  break;
  2107     // Might as well check the new outer against all available values.
  2108     if (next == class1())  return true;
  2109     if (next == outer1())  return true;
  2110     outer2 = instanceKlassHandle(THREAD, next);
  2113   // If by this point we have not found an equality between the
  2114   // two classes, we know they are in separate package members.
  2115   return false;
  2119 jint instanceKlass::compute_modifier_flags(TRAPS) const {
  2120   klassOop k = as_klassOop();
  2121   jint access = access_flags().as_int();
  2123   // But check if it happens to be member class.
  2124   typeArrayOop inner_class_list = inner_classes();
  2125   int length = (inner_class_list == NULL) ? 0 : inner_class_list->length();
  2126   assert (length % instanceKlass::inner_class_next_offset == 0, "just checking");
  2127   if (length > 0) {
  2128     typeArrayHandle inner_class_list_h(THREAD, inner_class_list);
  2129     instanceKlassHandle ik(THREAD, k);
  2130     for (int i = 0; i < length; i += instanceKlass::inner_class_next_offset) {
  2131       int ioff = inner_class_list_h->ushort_at(
  2132                       i + instanceKlass::inner_class_inner_class_info_offset);
  2134       // Inner class attribute can be zero, skip it.
  2135       // Strange but true:  JVM spec. allows null inner class refs.
  2136       if (ioff == 0) continue;
  2138       // only look at classes that are already loaded
  2139       // since we are looking for the flags for our self.
  2140       symbolOop inner_name = ik->constants()->klass_name_at(ioff);
  2141       if ((ik->name() == inner_name)) {
  2142         // This is really a member class.
  2143         access = inner_class_list_h->ushort_at(i + instanceKlass::inner_class_access_flags_offset);
  2144         break;
  2148   // Remember to strip ACC_SUPER bit
  2149   return (access & (~JVM_ACC_SUPER)) & JVM_ACC_WRITTEN_FLAGS;
  2152 jint instanceKlass::jvmti_class_status() const {
  2153   jint result = 0;
  2155   if (is_linked()) {
  2156     result |= JVMTI_CLASS_STATUS_VERIFIED | JVMTI_CLASS_STATUS_PREPARED;
  2159   if (is_initialized()) {
  2160     assert(is_linked(), "Class status is not consistent");
  2161     result |= JVMTI_CLASS_STATUS_INITIALIZED;
  2163   if (is_in_error_state()) {
  2164     result |= JVMTI_CLASS_STATUS_ERROR;
  2166   return result;
  2169 methodOop instanceKlass::method_at_itable(klassOop holder, int index, TRAPS) {
  2170   itableOffsetEntry* ioe = (itableOffsetEntry*)start_of_itable();
  2171   int method_table_offset_in_words = ioe->offset()/wordSize;
  2172   int nof_interfaces = (method_table_offset_in_words - itable_offset_in_words())
  2173                        / itableOffsetEntry::size();
  2175   for (int cnt = 0 ; ; cnt ++, ioe ++) {
  2176     // If the interface isn't implemented by the receiver class,
  2177     // the VM should throw IncompatibleClassChangeError.
  2178     if (cnt >= nof_interfaces) {
  2179       THROW_OOP_0(vmSymbols::java_lang_IncompatibleClassChangeError());
  2182     klassOop ik = ioe->interface_klass();
  2183     if (ik == holder) break;
  2186   itableMethodEntry* ime = ioe->first_method_entry(as_klassOop());
  2187   methodOop m = ime[index].method();
  2188   if (m == NULL) {
  2189     THROW_OOP_0(vmSymbols::java_lang_AbstractMethodError());
  2191   return m;
  2194 // On-stack replacement stuff
  2195 void instanceKlass::add_osr_nmethod(nmethod* n) {
  2196   // only one compilation can be active
  2197   NEEDS_CLEANUP
  2198   // This is a short non-blocking critical region, so the no safepoint check is ok.
  2199   OsrList_lock->lock_without_safepoint_check();
  2200   assert(n->is_osr_method(), "wrong kind of nmethod");
  2201   n->set_osr_link(osr_nmethods_head());
  2202   set_osr_nmethods_head(n);
  2203   // Raise the highest osr level if necessary
  2204   if (TieredCompilation) {
  2205     methodOop m = n->method();
  2206     m->set_highest_osr_comp_level(MAX2(m->highest_osr_comp_level(), n->comp_level()));
  2208   // Remember to unlock again
  2209   OsrList_lock->unlock();
  2211   // Get rid of the osr methods for the same bci that have lower levels.
  2212   if (TieredCompilation) {
  2213     for (int l = CompLevel_limited_profile; l < n->comp_level(); l++) {
  2214       nmethod *inv = lookup_osr_nmethod(n->method(), n->osr_entry_bci(), l, true);
  2215       if (inv != NULL && inv->is_in_use()) {
  2216         inv->make_not_entrant();
  2223 void instanceKlass::remove_osr_nmethod(nmethod* n) {
  2224   // This is a short non-blocking critical region, so the no safepoint check is ok.
  2225   OsrList_lock->lock_without_safepoint_check();
  2226   assert(n->is_osr_method(), "wrong kind of nmethod");
  2227   nmethod* last = NULL;
  2228   nmethod* cur  = osr_nmethods_head();
  2229   int max_level = CompLevel_none;  // Find the max comp level excluding n
  2230   methodOop m = n->method();
  2231   // Search for match
  2232   while(cur != NULL && cur != n) {
  2233     if (TieredCompilation) {
  2234       // Find max level before n
  2235       max_level = MAX2(max_level, cur->comp_level());
  2237     last = cur;
  2238     cur = cur->osr_link();
  2240   nmethod* next = NULL;
  2241   if (cur == n) {
  2242     next = cur->osr_link();
  2243     if (last == NULL) {
  2244       // Remove first element
  2245       set_osr_nmethods_head(next);
  2246     } else {
  2247       last->set_osr_link(next);
  2250   n->set_osr_link(NULL);
  2251   if (TieredCompilation) {
  2252     cur = next;
  2253     while (cur != NULL) {
  2254       // Find max level after n
  2255       max_level = MAX2(max_level, cur->comp_level());
  2256       cur = cur->osr_link();
  2258     m->set_highest_osr_comp_level(max_level);
  2260   // Remember to unlock again
  2261   OsrList_lock->unlock();
  2264 nmethod* instanceKlass::lookup_osr_nmethod(const methodOop m, int bci, int comp_level, bool match_level) const {
  2265   // This is a short non-blocking critical region, so the no safepoint check is ok.
  2266   OsrList_lock->lock_without_safepoint_check();
  2267   nmethod* osr = osr_nmethods_head();
  2268   nmethod* best = NULL;
  2269   while (osr != NULL) {
  2270     assert(osr->is_osr_method(), "wrong kind of nmethod found in chain");
  2271     // There can be a time when a c1 osr method exists but we are waiting
  2272     // for a c2 version. When c2 completes its osr nmethod we will trash
  2273     // the c1 version and only be able to find the c2 version. However
  2274     // while we overflow in the c1 code at back branches we don't want to
  2275     // try and switch to the same code as we are already running
  2277     if (osr->method() == m &&
  2278         (bci == InvocationEntryBci || osr->osr_entry_bci() == bci)) {
  2279       if (match_level) {
  2280         if (osr->comp_level() == comp_level) {
  2281           // Found a match - return it.
  2282           OsrList_lock->unlock();
  2283           return osr;
  2285       } else {
  2286         if (best == NULL || (osr->comp_level() > best->comp_level())) {
  2287           if (osr->comp_level() == CompLevel_highest_tier) {
  2288             // Found the best possible - return it.
  2289             OsrList_lock->unlock();
  2290             return osr;
  2292           best = osr;
  2296     osr = osr->osr_link();
  2298   OsrList_lock->unlock();
  2299   if (best != NULL && best->comp_level() >= comp_level && match_level == false) {
  2300     return best;
  2302   return NULL;
  2305 // -----------------------------------------------------------------------------------------------------
  2306 #ifndef PRODUCT
  2308 // Printing
  2310 #define BULLET  " - "
  2312 void FieldPrinter::do_field(fieldDescriptor* fd) {
  2313   _st->print(BULLET);
  2314    if (fd->is_static() || (_obj == NULL)) {
  2315      fd->print_on(_st);
  2316      _st->cr();
  2317    } else {
  2318      fd->print_on_for(_st, _obj);
  2319      _st->cr();
  2324 void instanceKlass::oop_print_on(oop obj, outputStream* st) {
  2325   Klass::oop_print_on(obj, st);
  2327   if (as_klassOop() == SystemDictionary::String_klass()) {
  2328     typeArrayOop value  = java_lang_String::value(obj);
  2329     juint        offset = java_lang_String::offset(obj);
  2330     juint        length = java_lang_String::length(obj);
  2331     if (value != NULL &&
  2332         value->is_typeArray() &&
  2333         offset          <= (juint) value->length() &&
  2334         offset + length <= (juint) value->length()) {
  2335       st->print(BULLET"string: ");
  2336       Handle h_obj(obj);
  2337       java_lang_String::print(h_obj, st);
  2338       st->cr();
  2339       if (!WizardMode)  return;  // that is enough
  2343   st->print_cr(BULLET"---- fields (total size %d words):", oop_size(obj));
  2344   FieldPrinter print_nonstatic_field(st, obj);
  2345   do_nonstatic_fields(&print_nonstatic_field);
  2347   if (as_klassOop() == SystemDictionary::Class_klass()) {
  2348     st->print(BULLET"signature: ");
  2349     java_lang_Class::print_signature(obj, st);
  2350     st->cr();
  2351     klassOop mirrored_klass = java_lang_Class::as_klassOop(obj);
  2352     st->print(BULLET"fake entry for mirror: ");
  2353     mirrored_klass->print_value_on(st);
  2354     st->cr();
  2355     st->print(BULLET"fake entry resolved_constructor: ");
  2356     methodOop ctor = java_lang_Class::resolved_constructor(obj);
  2357     ctor->print_value_on(st);
  2358     klassOop array_klass = java_lang_Class::array_klass(obj);
  2359     st->cr();
  2360     st->print(BULLET"fake entry for array: ");
  2361     array_klass->print_value_on(st);
  2362     st->cr();
  2363   } else if (as_klassOop() == SystemDictionary::MethodType_klass()) {
  2364     st->print(BULLET"signature: ");
  2365     java_dyn_MethodType::print_signature(obj, st);
  2366     st->cr();
  2370 #endif //PRODUCT
  2372 void instanceKlass::oop_print_value_on(oop obj, outputStream* st) {
  2373   st->print("a ");
  2374   name()->print_value_on(st);
  2375   obj->print_address_on(st);
  2376   if (as_klassOop() == SystemDictionary::String_klass()
  2377       && java_lang_String::value(obj) != NULL) {
  2378     ResourceMark rm;
  2379     int len = java_lang_String::length(obj);
  2380     int plen = (len < 24 ? len : 12);
  2381     char* str = java_lang_String::as_utf8_string(obj, 0, plen);
  2382     st->print(" = \"%s\"", str);
  2383     if (len > plen)
  2384       st->print("...[%d]", len);
  2385   } else if (as_klassOop() == SystemDictionary::Class_klass()) {
  2386     klassOop k = java_lang_Class::as_klassOop(obj);
  2387     st->print(" = ");
  2388     if (k != NULL) {
  2389       k->print_value_on(st);
  2390     } else {
  2391       const char* tname = type2name(java_lang_Class::primitive_type(obj));
  2392       st->print("%s", tname ? tname : "type?");
  2394   } else if (as_klassOop() == SystemDictionary::MethodType_klass()) {
  2395     st->print(" = ");
  2396     java_dyn_MethodType::print_signature(obj, st);
  2397   } else if (java_lang_boxing_object::is_instance(obj)) {
  2398     st->print(" = ");
  2399     java_lang_boxing_object::print(obj, st);
  2403 const char* instanceKlass::internal_name() const {
  2404   return external_name();
  2407 // Verification
  2409 class VerifyFieldClosure: public OopClosure {
  2410  protected:
  2411   template <class T> void do_oop_work(T* p) {
  2412     guarantee(Universe::heap()->is_in_closed_subset(p), "should be in heap");
  2413     oop obj = oopDesc::load_decode_heap_oop(p);
  2414     if (!obj->is_oop_or_null()) {
  2415       tty->print_cr("Failed: " PTR_FORMAT " -> " PTR_FORMAT, p, (address)obj);
  2416       Universe::print();
  2417       guarantee(false, "boom");
  2420  public:
  2421   virtual void do_oop(oop* p)       { VerifyFieldClosure::do_oop_work(p); }
  2422   virtual void do_oop(narrowOop* p) { VerifyFieldClosure::do_oop_work(p); }
  2423 };
  2425 void instanceKlass::oop_verify_on(oop obj, outputStream* st) {
  2426   Klass::oop_verify_on(obj, st);
  2427   VerifyFieldClosure blk;
  2428   oop_oop_iterate(obj, &blk);
  2431 #ifndef PRODUCT
  2433 void instanceKlass::verify_class_klass_nonstatic_oop_maps(klassOop k) {
  2434   // This verification code is disabled.  JDK_Version::is_gte_jdk14x_version()
  2435   // cannot be called since this function is called before the VM is
  2436   // able to determine what JDK version is running with.
  2437   // The check below always is false since 1.4.
  2438   return;
  2440   // This verification code temporarily disabled for the 1.4
  2441   // reflection implementation since java.lang.Class now has
  2442   // Java-level instance fields. Should rewrite this to handle this
  2443   // case.
  2444   if (!(JDK_Version::is_gte_jdk14x_version() && UseNewReflection)) {
  2445     // Verify that java.lang.Class instances have a fake oop field added.
  2446     instanceKlass* ik = instanceKlass::cast(k);
  2448     // Check that we have the right class
  2449     static bool first_time = true;
  2450     guarantee(k == SystemDictionary::Class_klass() && first_time, "Invalid verify of maps");
  2451     first_time = false;
  2452     const int extra = java_lang_Class::number_of_fake_oop_fields;
  2453     guarantee(ik->nonstatic_field_size() == extra, "just checking");
  2454     guarantee(ik->nonstatic_oop_map_count() == 1, "just checking");
  2455     guarantee(ik->size_helper() == align_object_size(instanceOopDesc::header_size() + extra), "just checking");
  2457     // Check that the map is (2,extra)
  2458     int offset = java_lang_Class::klass_offset;
  2460     OopMapBlock* map = ik->start_of_nonstatic_oop_maps();
  2461     guarantee(map->offset() == offset && map->count() == (unsigned int) extra,
  2462               "sanity");
  2466 #endif // ndef PRODUCT
  2468 // JNIid class for jfieldIDs only
  2469 // Note to reviewers:
  2470 // These JNI functions are just moved over to column 1 and not changed
  2471 // in the compressed oops workspace.
  2472 JNIid::JNIid(klassOop holder, int offset, JNIid* next) {
  2473   _holder = holder;
  2474   _offset = offset;
  2475   _next = next;
  2476   debug_only(_is_static_field_id = false;)
  2480 JNIid* JNIid::find(int offset) {
  2481   JNIid* current = this;
  2482   while (current != NULL) {
  2483     if (current->offset() == offset) return current;
  2484     current = current->next();
  2486   return NULL;
  2489 void JNIid::oops_do(OopClosure* f) {
  2490   for (JNIid* cur = this; cur != NULL; cur = cur->next()) {
  2491     f->do_oop(cur->holder_addr());
  2495 void JNIid::deallocate(JNIid* current) {
  2496   while (current != NULL) {
  2497     JNIid* next = current->next();
  2498     delete current;
  2499     current = next;
  2504 void JNIid::verify(klassOop holder) {
  2505   int first_field_offset  = instanceKlass::cast(holder)->offset_of_static_fields();
  2506   int end_field_offset;
  2507   end_field_offset = first_field_offset + (instanceKlass::cast(holder)->static_field_size() * wordSize);
  2509   JNIid* current = this;
  2510   while (current != NULL) {
  2511     guarantee(current->holder() == holder, "Invalid klass in JNIid");
  2512 #ifdef ASSERT
  2513     int o = current->offset();
  2514     if (current->is_static_field_id()) {
  2515       guarantee(o >= first_field_offset  && o < end_field_offset,  "Invalid static field offset in JNIid");
  2517 #endif
  2518     current = current->next();
  2523 #ifdef ASSERT
  2524 void instanceKlass::set_init_state(ClassState state) {
  2525   bool good_state = as_klassOop()->is_shared() ? (_init_state <= state)
  2526                                                : (_init_state < state);
  2527   assert(good_state || state == allocated, "illegal state transition");
  2528   _init_state = state;
  2530 #endif
  2533 // RedefineClasses() support for previous versions:
  2535 // Add an information node that contains weak references to the
  2536 // interesting parts of the previous version of the_class.
  2537 // This is also where we clean out any unused weak references.
  2538 // Note that while we delete nodes from the _previous_versions
  2539 // array, we never delete the array itself until the klass is
  2540 // unloaded. The has_been_redefined() query depends on that fact.
  2541 //
  2542 void instanceKlass::add_previous_version(instanceKlassHandle ikh,
  2543        BitMap* emcp_methods, int emcp_method_count) {
  2544   assert(Thread::current()->is_VM_thread(),
  2545          "only VMThread can add previous versions");
  2547   if (_previous_versions == NULL) {
  2548     // This is the first previous version so make some space.
  2549     // Start with 2 elements under the assumption that the class
  2550     // won't be redefined much.
  2551     _previous_versions =  new (ResourceObj::C_HEAP)
  2552                             GrowableArray<PreviousVersionNode *>(2, true);
  2555   // RC_TRACE macro has an embedded ResourceMark
  2556   RC_TRACE(0x00000100, ("adding previous version ref for %s @%d, EMCP_cnt=%d",
  2557     ikh->external_name(), _previous_versions->length(), emcp_method_count));
  2558   constantPoolHandle cp_h(ikh->constants());
  2559   jobject cp_ref;
  2560   if (cp_h->is_shared()) {
  2561     // a shared ConstantPool requires a regular reference; a weak
  2562     // reference would be collectible
  2563     cp_ref = JNIHandles::make_global(cp_h);
  2564   } else {
  2565     cp_ref = JNIHandles::make_weak_global(cp_h);
  2567   PreviousVersionNode * pv_node = NULL;
  2568   objArrayOop old_methods = ikh->methods();
  2570   if (emcp_method_count == 0) {
  2571     // non-shared ConstantPool gets a weak reference
  2572     pv_node = new PreviousVersionNode(cp_ref, !cp_h->is_shared(), NULL);
  2573     RC_TRACE(0x00000400,
  2574       ("add: all methods are obsolete; flushing any EMCP weak refs"));
  2575   } else {
  2576     int local_count = 0;
  2577     GrowableArray<jweak>* method_refs = new (ResourceObj::C_HEAP)
  2578       GrowableArray<jweak>(emcp_method_count, true);
  2579     for (int i = 0; i < old_methods->length(); i++) {
  2580       if (emcp_methods->at(i)) {
  2581         // this old method is EMCP so save a weak ref
  2582         methodOop old_method = (methodOop) old_methods->obj_at(i);
  2583         methodHandle old_method_h(old_method);
  2584         jweak method_ref = JNIHandles::make_weak_global(old_method_h);
  2585         method_refs->append(method_ref);
  2586         if (++local_count >= emcp_method_count) {
  2587           // no more EMCP methods so bail out now
  2588           break;
  2592     // non-shared ConstantPool gets a weak reference
  2593     pv_node = new PreviousVersionNode(cp_ref, !cp_h->is_shared(), method_refs);
  2596   _previous_versions->append(pv_node);
  2598   // Using weak references allows the interesting parts of previous
  2599   // classes to be GC'ed when they are no longer needed. Since the
  2600   // caller is the VMThread and we are at a safepoint, this is a good
  2601   // time to clear out unused weak references.
  2603   RC_TRACE(0x00000400, ("add: previous version length=%d",
  2604     _previous_versions->length()));
  2606   // skip the last entry since we just added it
  2607   for (int i = _previous_versions->length() - 2; i >= 0; i--) {
  2608     // check the previous versions array for a GC'ed weak refs
  2609     pv_node = _previous_versions->at(i);
  2610     cp_ref = pv_node->prev_constant_pool();
  2611     assert(cp_ref != NULL, "cp ref was unexpectedly cleared");
  2612     if (cp_ref == NULL) {
  2613       delete pv_node;
  2614       _previous_versions->remove_at(i);
  2615       // Since we are traversing the array backwards, we don't have to
  2616       // do anything special with the index.
  2617       continue;  // robustness
  2620     constantPoolOop cp = (constantPoolOop)JNIHandles::resolve(cp_ref);
  2621     if (cp == NULL) {
  2622       // this entry has been GC'ed so remove it
  2623       delete pv_node;
  2624       _previous_versions->remove_at(i);
  2625       // Since we are traversing the array backwards, we don't have to
  2626       // do anything special with the index.
  2627       continue;
  2628     } else {
  2629       RC_TRACE(0x00000400, ("add: previous version @%d is alive", i));
  2632     GrowableArray<jweak>* method_refs = pv_node->prev_EMCP_methods();
  2633     if (method_refs != NULL) {
  2634       RC_TRACE(0x00000400, ("add: previous methods length=%d",
  2635         method_refs->length()));
  2636       for (int j = method_refs->length() - 1; j >= 0; j--) {
  2637         jweak method_ref = method_refs->at(j);
  2638         assert(method_ref != NULL, "weak method ref was unexpectedly cleared");
  2639         if (method_ref == NULL) {
  2640           method_refs->remove_at(j);
  2641           // Since we are traversing the array backwards, we don't have to
  2642           // do anything special with the index.
  2643           continue;  // robustness
  2646         methodOop method = (methodOop)JNIHandles::resolve(method_ref);
  2647         if (method == NULL || emcp_method_count == 0) {
  2648           // This method entry has been GC'ed or the current
  2649           // RedefineClasses() call has made all methods obsolete
  2650           // so remove it.
  2651           JNIHandles::destroy_weak_global(method_ref);
  2652           method_refs->remove_at(j);
  2653         } else {
  2654           // RC_TRACE macro has an embedded ResourceMark
  2655           RC_TRACE(0x00000400,
  2656             ("add: %s(%s): previous method @%d in version @%d is alive",
  2657             method->name()->as_C_string(), method->signature()->as_C_string(),
  2658             j, i));
  2664   int obsolete_method_count = old_methods->length() - emcp_method_count;
  2666   if (emcp_method_count != 0 && obsolete_method_count != 0 &&
  2667       _previous_versions->length() > 1) {
  2668     // We have a mix of obsolete and EMCP methods. If there is more
  2669     // than the previous version that we just added, then we have to
  2670     // clear out any matching EMCP method entries the hard way.
  2671     int local_count = 0;
  2672     for (int i = 0; i < old_methods->length(); i++) {
  2673       if (!emcp_methods->at(i)) {
  2674         // only obsolete methods are interesting
  2675         methodOop old_method = (methodOop) old_methods->obj_at(i);
  2676         symbolOop m_name = old_method->name();
  2677         symbolOop m_signature = old_method->signature();
  2679         // skip the last entry since we just added it
  2680         for (int j = _previous_versions->length() - 2; j >= 0; j--) {
  2681           // check the previous versions array for a GC'ed weak refs
  2682           pv_node = _previous_versions->at(j);
  2683           cp_ref = pv_node->prev_constant_pool();
  2684           assert(cp_ref != NULL, "cp ref was unexpectedly cleared");
  2685           if (cp_ref == NULL) {
  2686             delete pv_node;
  2687             _previous_versions->remove_at(j);
  2688             // Since we are traversing the array backwards, we don't have to
  2689             // do anything special with the index.
  2690             continue;  // robustness
  2693           constantPoolOop cp = (constantPoolOop)JNIHandles::resolve(cp_ref);
  2694           if (cp == NULL) {
  2695             // this entry has been GC'ed so remove it
  2696             delete pv_node;
  2697             _previous_versions->remove_at(j);
  2698             // Since we are traversing the array backwards, we don't have to
  2699             // do anything special with the index.
  2700             continue;
  2703           GrowableArray<jweak>* method_refs = pv_node->prev_EMCP_methods();
  2704           if (method_refs == NULL) {
  2705             // We have run into a PreviousVersion generation where
  2706             // all methods were made obsolete during that generation's
  2707             // RedefineClasses() operation. At the time of that
  2708             // operation, all EMCP methods were flushed so we don't
  2709             // have to go back any further.
  2710             //
  2711             // A NULL method_refs is different than an empty method_refs.
  2712             // We cannot infer any optimizations about older generations
  2713             // from an empty method_refs for the current generation.
  2714             break;
  2717           for (int k = method_refs->length() - 1; k >= 0; k--) {
  2718             jweak method_ref = method_refs->at(k);
  2719             assert(method_ref != NULL,
  2720               "weak method ref was unexpectedly cleared");
  2721             if (method_ref == NULL) {
  2722               method_refs->remove_at(k);
  2723               // Since we are traversing the array backwards, we don't
  2724               // have to do anything special with the index.
  2725               continue;  // robustness
  2728             methodOop method = (methodOop)JNIHandles::resolve(method_ref);
  2729             if (method == NULL) {
  2730               // this method entry has been GC'ed so skip it
  2731               JNIHandles::destroy_weak_global(method_ref);
  2732               method_refs->remove_at(k);
  2733               continue;
  2736             if (method->name() == m_name &&
  2737                 method->signature() == m_signature) {
  2738               // The current RedefineClasses() call has made all EMCP
  2739               // versions of this method obsolete so mark it as obsolete
  2740               // and remove the weak ref.
  2741               RC_TRACE(0x00000400,
  2742                 ("add: %s(%s): flush obsolete method @%d in version @%d",
  2743                 m_name->as_C_string(), m_signature->as_C_string(), k, j));
  2745               method->set_is_obsolete();
  2746               JNIHandles::destroy_weak_global(method_ref);
  2747               method_refs->remove_at(k);
  2748               break;
  2752           // The previous loop may not find a matching EMCP method, but
  2753           // that doesn't mean that we can optimize and not go any
  2754           // further back in the PreviousVersion generations. The EMCP
  2755           // method for this generation could have already been GC'ed,
  2756           // but there still may be an older EMCP method that has not
  2757           // been GC'ed.
  2760         if (++local_count >= obsolete_method_count) {
  2761           // no more obsolete methods so bail out now
  2762           break;
  2767 } // end add_previous_version()
  2770 // Determine if instanceKlass has a previous version.
  2771 bool instanceKlass::has_previous_version() const {
  2772   if (_previous_versions == NULL) {
  2773     // no previous versions array so answer is easy
  2774     return false;
  2777   for (int i = _previous_versions->length() - 1; i >= 0; i--) {
  2778     // Check the previous versions array for an info node that hasn't
  2779     // been GC'ed
  2780     PreviousVersionNode * pv_node = _previous_versions->at(i);
  2782     jobject cp_ref = pv_node->prev_constant_pool();
  2783     assert(cp_ref != NULL, "cp reference was unexpectedly cleared");
  2784     if (cp_ref == NULL) {
  2785       continue;  // robustness
  2788     constantPoolOop cp = (constantPoolOop)JNIHandles::resolve(cp_ref);
  2789     if (cp != NULL) {
  2790       // we have at least one previous version
  2791       return true;
  2794     // We don't have to check the method refs. If the constant pool has
  2795     // been GC'ed then so have the methods.
  2798   // all of the underlying nodes' info has been GC'ed
  2799   return false;
  2800 } // end has_previous_version()
  2802 methodOop instanceKlass::method_with_idnum(int idnum) {
  2803   methodOop m = NULL;
  2804   if (idnum < methods()->length()) {
  2805     m = (methodOop) methods()->obj_at(idnum);
  2807   if (m == NULL || m->method_idnum() != idnum) {
  2808     for (int index = 0; index < methods()->length(); ++index) {
  2809       m = (methodOop) methods()->obj_at(index);
  2810       if (m->method_idnum() == idnum) {
  2811         return m;
  2815   return m;
  2819 // Set the annotation at 'idnum' to 'anno'.
  2820 // We don't want to create or extend the array if 'anno' is NULL, since that is the
  2821 // default value.  However, if the array exists and is long enough, we must set NULL values.
  2822 void instanceKlass::set_methods_annotations_of(int idnum, typeArrayOop anno, objArrayOop* md_p) {
  2823   objArrayOop md = *md_p;
  2824   if (md != NULL && md->length() > idnum) {
  2825     md->obj_at_put(idnum, anno);
  2826   } else if (anno != NULL) {
  2827     // create the array
  2828     int length = MAX2(idnum+1, (int)_idnum_allocated_count);
  2829     md = oopFactory::new_system_objArray(length, Thread::current());
  2830     if (*md_p != NULL) {
  2831       // copy the existing entries
  2832       for (int index = 0; index < (*md_p)->length(); index++) {
  2833         md->obj_at_put(index, (*md_p)->obj_at(index));
  2836     set_annotations(md, md_p);
  2837     md->obj_at_put(idnum, anno);
  2838   } // if no array and idnum isn't included there is nothing to do
  2841 // Construct a PreviousVersionNode entry for the array hung off
  2842 // the instanceKlass.
  2843 PreviousVersionNode::PreviousVersionNode(jobject prev_constant_pool,
  2844   bool prev_cp_is_weak, GrowableArray<jweak>* prev_EMCP_methods) {
  2846   _prev_constant_pool = prev_constant_pool;
  2847   _prev_cp_is_weak = prev_cp_is_weak;
  2848   _prev_EMCP_methods = prev_EMCP_methods;
  2852 // Destroy a PreviousVersionNode
  2853 PreviousVersionNode::~PreviousVersionNode() {
  2854   if (_prev_constant_pool != NULL) {
  2855     if (_prev_cp_is_weak) {
  2856       JNIHandles::destroy_weak_global(_prev_constant_pool);
  2857     } else {
  2858       JNIHandles::destroy_global(_prev_constant_pool);
  2862   if (_prev_EMCP_methods != NULL) {
  2863     for (int i = _prev_EMCP_methods->length() - 1; i >= 0; i--) {
  2864       jweak method_ref = _prev_EMCP_methods->at(i);
  2865       if (method_ref != NULL) {
  2866         JNIHandles::destroy_weak_global(method_ref);
  2869     delete _prev_EMCP_methods;
  2874 // Construct a PreviousVersionInfo entry
  2875 PreviousVersionInfo::PreviousVersionInfo(PreviousVersionNode *pv_node) {
  2876   _prev_constant_pool_handle = constantPoolHandle();  // NULL handle
  2877   _prev_EMCP_method_handles = NULL;
  2879   jobject cp_ref = pv_node->prev_constant_pool();
  2880   assert(cp_ref != NULL, "constant pool ref was unexpectedly cleared");
  2881   if (cp_ref == NULL) {
  2882     return;  // robustness
  2885   constantPoolOop cp = (constantPoolOop)JNIHandles::resolve(cp_ref);
  2886   if (cp == NULL) {
  2887     // Weak reference has been GC'ed. Since the constant pool has been
  2888     // GC'ed, the methods have also been GC'ed.
  2889     return;
  2892   // make the constantPoolOop safe to return
  2893   _prev_constant_pool_handle = constantPoolHandle(cp);
  2895   GrowableArray<jweak>* method_refs = pv_node->prev_EMCP_methods();
  2896   if (method_refs == NULL) {
  2897     // the instanceKlass did not have any EMCP methods
  2898     return;
  2901   _prev_EMCP_method_handles = new GrowableArray<methodHandle>(10);
  2903   int n_methods = method_refs->length();
  2904   for (int i = 0; i < n_methods; i++) {
  2905     jweak method_ref = method_refs->at(i);
  2906     assert(method_ref != NULL, "weak method ref was unexpectedly cleared");
  2907     if (method_ref == NULL) {
  2908       continue;  // robustness
  2911     methodOop method = (methodOop)JNIHandles::resolve(method_ref);
  2912     if (method == NULL) {
  2913       // this entry has been GC'ed so skip it
  2914       continue;
  2917     // make the methodOop safe to return
  2918     _prev_EMCP_method_handles->append(methodHandle(method));
  2923 // Destroy a PreviousVersionInfo
  2924 PreviousVersionInfo::~PreviousVersionInfo() {
  2925   // Since _prev_EMCP_method_handles is not C-heap allocated, we
  2926   // don't have to delete it.
  2930 // Construct a helper for walking the previous versions array
  2931 PreviousVersionWalker::PreviousVersionWalker(instanceKlass *ik) {
  2932   _previous_versions = ik->previous_versions();
  2933   _current_index = 0;
  2934   // _hm needs no initialization
  2935   _current_p = NULL;
  2939 // Destroy a PreviousVersionWalker
  2940 PreviousVersionWalker::~PreviousVersionWalker() {
  2941   // Delete the current info just in case the caller didn't walk to
  2942   // the end of the previous versions list. No harm if _current_p is
  2943   // already NULL.
  2944   delete _current_p;
  2946   // When _hm is destroyed, all the Handles returned in
  2947   // PreviousVersionInfo objects will be destroyed.
  2948   // Also, after this destructor is finished it will be
  2949   // safe to delete the GrowableArray allocated in the
  2950   // PreviousVersionInfo objects.
  2954 // Return the interesting information for the next previous version
  2955 // of the klass. Returns NULL if there are no more previous versions.
  2956 PreviousVersionInfo* PreviousVersionWalker::next_previous_version() {
  2957   if (_previous_versions == NULL) {
  2958     // no previous versions so nothing to return
  2959     return NULL;
  2962   delete _current_p;  // cleanup the previous info for the caller
  2963   _current_p = NULL;  // reset to NULL so we don't delete same object twice
  2965   int length = _previous_versions->length();
  2967   while (_current_index < length) {
  2968     PreviousVersionNode * pv_node = _previous_versions->at(_current_index++);
  2969     PreviousVersionInfo * pv_info = new (ResourceObj::C_HEAP)
  2970                                           PreviousVersionInfo(pv_node);
  2972     constantPoolHandle cp_h = pv_info->prev_constant_pool_handle();
  2973     if (cp_h.is_null()) {
  2974       delete pv_info;
  2976       // The underlying node's info has been GC'ed so try the next one.
  2977       // We don't have to check the methods. If the constant pool has
  2978       // GC'ed then so have the methods.
  2979       continue;
  2982     // Found a node with non GC'ed info so return it. The caller will
  2983     // need to delete pv_info when they are done with it.
  2984     _current_p = pv_info;
  2985     return pv_info;
  2988   // all of the underlying nodes' info has been GC'ed
  2989   return NULL;
  2990 } // end next_previous_version()

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