Mercurial > jdk8-mips64-public > hotspot / file revision

 /*

  * Copyright (c) 1997, 2011, Oracle and/or its affiliates. All rights reserved.

  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

  *

  * This code is free software; you can redistribute it and/or modify it

  * under the terms of the GNU General Public License version 2 only, as

  * published by the Free Software Foundation.

  *

  * This code is distributed in the hope that it will be useful, but WITHOUT

  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

  * version 2 for more details (a copy is included in the LICENSE file that

  * accompanied this code).

  *

  * You should have received a copy of the GNU General Public License version

  * 2 along with this work; if not, write to the Free Software Foundation,

  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

  *

  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

  * or visit www.oracle.com if you need additional information or have any

  * questions.

  *

  */

 #include "precompiled.hpp"

 #include "classfile/javaClasses.hpp"

 #include "classfile/systemDictionary.hpp"

 #include "classfile/verifier.hpp"

 #include "classfile/vmSymbols.hpp"

 #include "compiler/compileBroker.hpp"

 #include "gc_implementation/shared/markSweep.inline.hpp"

 #include "gc_interface/collectedHeap.inline.hpp"

 #include "interpreter/oopMapCache.hpp"

 #include "interpreter/rewriter.hpp"

 #include "jvmtifiles/jvmti.h"

 #include "memory/genOopClosures.inline.hpp"

 #include "memory/oopFactory.hpp"

 #include "memory/permGen.hpp"

 #include "oops/fieldStreams.hpp"

 #include "oops/instanceKlass.hpp"

 #include "oops/instanceMirrorKlass.hpp"

 #include "oops/instanceOop.hpp"

 #include "oops/methodOop.hpp"

 #include "oops/objArrayKlassKlass.hpp"

 #include "oops/oop.inline.hpp"

 #include "oops/symbol.hpp"

 #include "prims/jvmtiExport.hpp"

 #include "prims/jvmtiRedefineClassesTrace.hpp"

 #include "runtime/fieldDescriptor.hpp"

 #include "runtime/handles.inline.hpp"

 #include "runtime/javaCalls.hpp"

 #include "runtime/mutexLocker.hpp"

 #include "services/threadService.hpp"

 #include "utilities/dtrace.hpp"

 #ifdef TARGET_OS_FAMILY_linux

 # include "thread_linux.inline.hpp"

 #endif

 #ifdef TARGET_OS_FAMILY_solaris

 # include "thread_solaris.inline.hpp"

 #endif

 #ifdef TARGET_OS_FAMILY_windows

 # include "thread_windows.inline.hpp"

 #endif

 #ifdef TARGET_OS_FAMILY_bsd

 # include "thread_bsd.inline.hpp"

 #endif

 #ifndef SERIALGC

 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"

 #include "gc_implementation/g1/g1OopClosures.inline.hpp"

 #include "gc_implementation/g1/g1RemSet.inline.hpp"

 #include "gc_implementation/g1/heapRegionSeq.inline.hpp"

 #include "gc_implementation/parNew/parOopClosures.inline.hpp"

 #include "gc_implementation/parallelScavenge/psPromotionManager.inline.hpp"

 #include "gc_implementation/parallelScavenge/psScavenge.inline.hpp"

 #include "oops/oop.pcgc.inline.hpp"

 #endif

 #ifdef COMPILER1

 #include "c1/c1_Compiler.hpp"

 #endif

 #ifdef DTRACE_ENABLED

 #ifndef USDT2

 HS_DTRACE_PROBE_DECL4(hotspot, class__initialization__required,

   char*, intptr_t, oop, intptr_t);

 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__recursive,

   char*, intptr_t, oop, intptr_t, int);

 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__concurrent,

   char*, intptr_t, oop, intptr_t, int);

 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__erroneous,

   char*, intptr_t, oop, intptr_t, int);

 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__super__failed,

   char*, intptr_t, oop, intptr_t, int);

 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__clinit,

   char*, intptr_t, oop, intptr_t, int);

 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__error,

   char*, intptr_t, oop, intptr_t, int);

 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__end,

   char*, intptr_t, oop, intptr_t, int);

 #define DTRACE_CLASSINIT_PROBE(type, clss, thread_type)          \

   {                                                              \

     char* data = NULL;                                           \

     int len = 0;                                                 \

     Symbol* name = (clss)->name();                               \

     if (name != NULL) {                                          \

       data = (char*)name->bytes();                               \

       len = name->utf8_length();                                 \

     }                                                            \

     HS_DTRACE_PROBE4(hotspot, class__initialization__##type,     \

       data, len, (clss)->class_loader(), thread_type);           \

   }

 #define DTRACE_CLASSINIT_PROBE_WAIT(type, clss, thread_type, wait) \

   {                                                              \

     char* data = NULL;                                           \

     int len = 0;                                                 \

     Symbol* name = (clss)->name();                               \

     if (name != NULL) {                                          \

       data = (char*)name->bytes();                               \

       len = name->utf8_length();                                 \

     }                                                            \

     HS_DTRACE_PROBE5(hotspot, class__initialization__##type,     \

       data, len, (clss)->class_loader(), thread_type, wait);     \

   }

 #else /* USDT2 */

 #define HOTSPOT_CLASS_INITIALIZATION_required HOTSPOT_CLASS_INITIALIZATION_REQUIRED

 #define HOTSPOT_CLASS_INITIALIZATION_recursive HOTSPOT_CLASS_INITIALIZATION_RECURSIVE

 #define HOTSPOT_CLASS_INITIALIZATION_concurrent HOTSPOT_CLASS_INITIALIZATION_CONCURRENT

 #define HOTSPOT_CLASS_INITIALIZATION_erroneous HOTSPOT_CLASS_INITIALIZATION_ERRONEOUS

 #define HOTSPOT_CLASS_INITIALIZATION_super__failed HOTSPOT_CLASS_INITIALIZATION_SUPER_FAILED

 #define HOTSPOT_CLASS_INITIALIZATION_clinit HOTSPOT_CLASS_INITIALIZATION_CLINIT

 #define HOTSPOT_CLASS_INITIALIZATION_error HOTSPOT_CLASS_INITIALIZATION_ERROR

 #define HOTSPOT_CLASS_INITIALIZATION_end HOTSPOT_CLASS_INITIALIZATION_END

 #define DTRACE_CLASSINIT_PROBE(type, clss, thread_type)          \

   {                                                              \

     char* data = NULL;                                           \

     int len = 0;                                                 \

     Symbol* name = (clss)->name();                               \

     if (name != NULL) {                                          \

       data = (char*)name->bytes();                               \

       len = name->utf8_length();                                 \

     }                                                            \

     HOTSPOT_CLASS_INITIALIZATION_##type(                         \

       data, len, (clss)->class_loader(), thread_type);           \

   }

 #define DTRACE_CLASSINIT_PROBE_WAIT(type, clss, thread_type, wait) \

   {                                                              \

     char* data = NULL;                                           \

     int len = 0;                                                 \

     Symbol* name = (clss)->name();                               \

     if (name != NULL) {                                          \

       data = (char*)name->bytes();                               \

       len = name->utf8_length();                                 \

     }                                                            \

     HOTSPOT_CLASS_INITIALIZATION_##type(                         \

       data, len, (clss)->class_loader(), thread_type, wait);     \

   }

 #endif /* USDT2 */

 #else //  ndef DTRACE_ENABLED

 #define DTRACE_CLASSINIT_PROBE(type, clss, thread_type)

 #define DTRACE_CLASSINIT_PROBE_WAIT(type, clss, thread_type, wait)

 #endif //  ndef DTRACE_ENABLED

 bool instanceKlass::should_be_initialized() const {

   return !is_initialized();

 }

 klassVtable* instanceKlass::vtable() const {

   return new klassVtable(as_klassOop(), start_of_vtable(), vtable_length() / vtableEntry::size());

 }

 klassItable* instanceKlass::itable() const {

   return new klassItable(as_klassOop());

 }

 void instanceKlass::eager_initialize(Thread *thread) {

   if (!EagerInitialization) return;

   if (this->is_not_initialized()) {

     // abort if the the class has a class initializer

     if (this->class_initializer() != NULL) return;

     // abort if it is java.lang.Object (initialization is handled in genesis)

     klassOop super = this->super();

     if (super == NULL) return;

     // abort if the super class should be initialized

     if (!instanceKlass::cast(super)->is_initialized()) return;

     // call body to expose the this pointer

     instanceKlassHandle this_oop(thread, this->as_klassOop());

     eager_initialize_impl(this_oop);

   }

 }

 void instanceKlass::eager_initialize_impl(instanceKlassHandle this_oop) {

   EXCEPTION_MARK;

   ObjectLocker ol(this_oop, THREAD);

   // abort if someone beat us to the initialization

   if (!this_oop->is_not_initialized()) return;  // note: not equivalent to is_initialized()

   ClassState old_state = this_oop->init_state();

   link_class_impl(this_oop, true, THREAD);

   if (HAS_PENDING_EXCEPTION) {

     CLEAR_PENDING_EXCEPTION;

     // Abort if linking the class throws an exception.

     // Use a test to avoid redundantly resetting the state if there's

     // no change.  Set_init_state() asserts that state changes make

     // progress, whereas here we might just be spinning in place.

     if( old_state != this_oop->_init_state )

       this_oop->set_init_state (old_state);

   } else {

     // linking successfull, mark class as initialized

     this_oop->set_init_state (fully_initialized);

     // trace

     if (TraceClassInitialization) {

       ResourceMark rm(THREAD);

       tty->print_cr("[Initialized %s without side effects]", this_oop->external_name());

     }

   }

 }

 // See "The Virtual Machine Specification" section 2.16.5 for a detailed explanation of the class initialization

 // process. The step comments refers to the procedure described in that section.

 // Note: implementation moved to static method to expose the this pointer.

 void instanceKlass::initialize(TRAPS) {

   if (this->should_be_initialized()) {

     HandleMark hm(THREAD);

     instanceKlassHandle this_oop(THREAD, this->as_klassOop());

     initialize_impl(this_oop, CHECK);

     // Note: at this point the class may be initialized

     //       OR it may be in the state of being initialized

     //       in case of recursive initialization!

   } else {

     assert(is_initialized(), "sanity check");

   }

 }

 bool instanceKlass::verify_code(

     instanceKlassHandle this_oop, bool throw_verifyerror, TRAPS) {

   // 1) Verify the bytecodes

   Verifier::Mode mode =

     throw_verifyerror ? Verifier::ThrowException : Verifier::NoException;

   return Verifier::verify(this_oop, mode, this_oop->should_verify_class(), CHECK_false);

 }

 // Used exclusively by the shared spaces dump mechanism to prevent

 // classes mapped into the shared regions in new VMs from appearing linked.

 void instanceKlass::unlink_class() {

   assert(is_linked(), "must be linked");

   _init_state = loaded;

 }

 void instanceKlass::link_class(TRAPS) {

   assert(is_loaded(), "must be loaded");

   if (!is_linked()) {

     instanceKlassHandle this_oop(THREAD, this->as_klassOop());

     link_class_impl(this_oop, true, CHECK);

   }

 }

 // Called to verify that a class can link during initialization, without

 // throwing a VerifyError.

 bool instanceKlass::link_class_or_fail(TRAPS) {

   assert(is_loaded(), "must be loaded");

   if (!is_linked()) {

     instanceKlassHandle this_oop(THREAD, this->as_klassOop());

     link_class_impl(this_oop, false, CHECK_false);

   }

   return is_linked();

 }

 bool instanceKlass::link_class_impl(

     instanceKlassHandle this_oop, bool throw_verifyerror, TRAPS) {

   // check for error state

   if (this_oop->is_in_error_state()) {

     ResourceMark rm(THREAD);

     THROW_MSG_(vmSymbols::java_lang_NoClassDefFoundError(),

                this_oop->external_name(), false);

   }

   // return if already verified

   if (this_oop->is_linked()) {

     return true;

   }

   // Timing

   // timer handles recursion

   assert(THREAD->is_Java_thread(), "non-JavaThread in link_class_impl");

   JavaThread* jt = (JavaThread*)THREAD;

   // link super class before linking this class

   instanceKlassHandle super(THREAD, this_oop->super());

   if (super.not_null()) {

     if (super->is_interface()) {  // check if super class is an interface

       ResourceMark rm(THREAD);

       Exceptions::fthrow(

         THREAD_AND_LOCATION,

         vmSymbols::java_lang_IncompatibleClassChangeError(),

         "class %s has interface %s as super class",

         this_oop->external_name(),

         super->external_name()

       );

       return false;

     }

     link_class_impl(super, throw_verifyerror, CHECK_false);

   }

   // link all interfaces implemented by this class before linking this class

   objArrayHandle interfaces (THREAD, this_oop->local_interfaces());

   int num_interfaces = interfaces->length();

   for (int index = 0; index < num_interfaces; index++) {

     HandleMark hm(THREAD);

     instanceKlassHandle ih(THREAD, klassOop(interfaces->obj_at(index)));

     link_class_impl(ih, throw_verifyerror, CHECK_false);

   }

   // in case the class is linked in the process of linking its superclasses

   if (this_oop->is_linked()) {

     return true;

   }

   // trace only the link time for this klass that includes

   // the verification time

   PerfClassTraceTime vmtimer(ClassLoader::perf_class_link_time(),

                              ClassLoader::perf_class_link_selftime(),

                              ClassLoader::perf_classes_linked(),

                              jt->get_thread_stat()->perf_recursion_counts_addr(),

                              jt->get_thread_stat()->perf_timers_addr(),

                              PerfClassTraceTime::CLASS_LINK);

   // verification & rewriting

   {

     ObjectLocker ol(this_oop, THREAD);

     // rewritten will have been set if loader constraint error found

     // on an earlier link attempt

     // don't verify or rewrite if already rewritten

     if (!this_oop->is_linked()) {

       if (!this_oop->is_rewritten()) {

         {

           // Timer includes any side effects of class verification (resolution,

           // etc), but not recursive entry into verify_code().

           PerfClassTraceTime timer(ClassLoader::perf_class_verify_time(),

                                    ClassLoader::perf_class_verify_selftime(),

                                    ClassLoader::perf_classes_verified(),

                                    jt->get_thread_stat()->perf_recursion_counts_addr(),

                                    jt->get_thread_stat()->perf_timers_addr(),

                                    PerfClassTraceTime::CLASS_VERIFY);

           bool verify_ok = verify_code(this_oop, throw_verifyerror, THREAD);

           if (!verify_ok) {

             return false;

           }

         }

         // Just in case a side-effect of verify linked this class already

         // (which can sometimes happen since the verifier loads classes

         // using custom class loaders, which are free to initialize things)

         if (this_oop->is_linked()) {

           return true;

         }

         // also sets rewritten

         this_oop->rewrite_class(CHECK_false);

       }

       // relocate jsrs and link methods after they are all rewritten

       this_oop->relocate_and_link_methods(CHECK_false);

       // Initialize the vtable and interface table after

       // methods have been rewritten since rewrite may

       // fabricate new methodOops.

       // also does loader constraint checking

       if (!this_oop()->is_shared()) {

         ResourceMark rm(THREAD);

         this_oop->vtable()->initialize_vtable(true, CHECK_false);

         this_oop->itable()->initialize_itable(true, CHECK_false);

       }

 #ifdef ASSERT

       else {

         ResourceMark rm(THREAD);

         this_oop->vtable()->verify(tty, true);

         // In case itable verification is ever added.

         // this_oop->itable()->verify(tty, true);

       }

 #endif

       this_oop->set_init_state(linked);

       if (JvmtiExport::should_post_class_prepare()) {

         Thread *thread = THREAD;

         assert(thread->is_Java_thread(), "thread->is_Java_thread()");

         JvmtiExport::post_class_prepare((JavaThread *) thread, this_oop());

       }

     }

   }

   return true;

 }

 // Rewrite the byte codes of all of the methods of a class.

 // The rewriter must be called exactly once. Rewriting must happen after

 // verification but before the first method of the class is executed.

 void instanceKlass::rewrite_class(TRAPS) {

   assert(is_loaded(), "must be loaded");

   instanceKlassHandle this_oop(THREAD, this->as_klassOop());

   if (this_oop->is_rewritten()) {

     assert(this_oop()->is_shared(), "rewriting an unshared class?");

     return;

   }

   Rewriter::rewrite(this_oop, CHECK);

   this_oop->set_rewritten();

 }

 // Now relocate and link method entry points after class is rewritten.

 // This is outside is_rewritten flag. In case of an exception, it can be

 // executed more than once.

 void instanceKlass::relocate_and_link_methods(TRAPS) {

   assert(is_loaded(), "must be loaded");

   instanceKlassHandle this_oop(THREAD, this->as_klassOop());

   Rewriter::relocate_and_link(this_oop, CHECK);

 }

 void instanceKlass::initialize_impl(instanceKlassHandle this_oop, TRAPS) {

   // Make sure klass is linked (verified) before initialization

   // A class could already be verified, since it has been reflected upon.

   this_oop->link_class(CHECK);

   DTRACE_CLASSINIT_PROBE(required, instanceKlass::cast(this_oop()), -1);

   bool wait = false;

   // refer to the JVM book page 47 for description of steps

   // Step 1

   { ObjectLocker ol(this_oop, THREAD);

     Thread *self = THREAD; // it's passed the current thread

     // Step 2

     // If we were to use wait() instead of waitInterruptibly() then

     // we might end up throwing IE from link/symbol resolution sites

     // that aren't expected to throw.  This would wreak havoc.  See 6320309.

     while(this_oop->is_being_initialized() && !this_oop->is_reentrant_initialization(self)) {

         wait = true;

       ol.waitUninterruptibly(CHECK);

     }

     // Step 3

     if (this_oop->is_being_initialized() && this_oop->is_reentrant_initialization(self)) {

       DTRACE_CLASSINIT_PROBE_WAIT(recursive, instanceKlass::cast(this_oop()), -1,wait);

       return;

     }

     // Step 4

     if (this_oop->is_initialized()) {

       DTRACE_CLASSINIT_PROBE_WAIT(concurrent, instanceKlass::cast(this_oop()), -1,wait);

       return;

     }

     // Step 5

     if (this_oop->is_in_error_state()) {

       DTRACE_CLASSINIT_PROBE_WAIT(erroneous, instanceKlass::cast(this_oop()), -1,wait);

       ResourceMark rm(THREAD);

       const char* desc = "Could not initialize class ";

       const char* className = this_oop->external_name();

       size_t msglen = strlen(desc) + strlen(className) + 1;

       char* message = NEW_RESOURCE_ARRAY(char, msglen);

       if (NULL == message) {

         // Out of memory: can't create detailed error message

         THROW_MSG(vmSymbols::java_lang_NoClassDefFoundError(), className);

       } else {

         jio_snprintf(message, msglen, "%s%s", desc, className);

         THROW_MSG(vmSymbols::java_lang_NoClassDefFoundError(), message);

       }

     }

     // Step 6

     this_oop->set_init_state(being_initialized);

     this_oop->set_init_thread(self);

   }

   // Step 7

   klassOop super_klass = this_oop->super();

   if (super_klass != NULL && !this_oop->is_interface() && Klass::cast(super_klass)->should_be_initialized()) {

     Klass::cast(super_klass)->initialize(THREAD);

     if (HAS_PENDING_EXCEPTION) {

       Handle e(THREAD, PENDING_EXCEPTION);

       CLEAR_PENDING_EXCEPTION;

       {

         EXCEPTION_MARK;

         this_oop->set_initialization_state_and_notify(initialization_error, THREAD); // Locks object, set state, and notify all waiting threads

         CLEAR_PENDING_EXCEPTION;   // ignore any exception thrown, superclass initialization error is thrown below

       }

       DTRACE_CLASSINIT_PROBE_WAIT(super__failed, instanceKlass::cast(this_oop()), -1,wait);

       THROW_OOP(e());

     }

   }

   // Step 8

   {

     assert(THREAD->is_Java_thread(), "non-JavaThread in initialize_impl");

     JavaThread* jt = (JavaThread*)THREAD;

     DTRACE_CLASSINIT_PROBE_WAIT(clinit, instanceKlass::cast(this_oop()), -1,wait);

     // Timer includes any side effects of class initialization (resolution,

     // etc), but not recursive entry into call_class_initializer().

     PerfClassTraceTime timer(ClassLoader::perf_class_init_time(),

                              ClassLoader::perf_class_init_selftime(),

                              ClassLoader::perf_classes_inited(),

                              jt->get_thread_stat()->perf_recursion_counts_addr(),

                              jt->get_thread_stat()->perf_timers_addr(),

                              PerfClassTraceTime::CLASS_CLINIT);

     this_oop->call_class_initializer(THREAD);

   }

   // Step 9

   if (!HAS_PENDING_EXCEPTION) {

     this_oop->set_initialization_state_and_notify(fully_initialized, CHECK);

     { ResourceMark rm(THREAD);

       debug_only(this_oop->vtable()->verify(tty, true);)

     }

   }

   else {

     // Step 10 and 11

     Handle e(THREAD, PENDING_EXCEPTION);

     CLEAR_PENDING_EXCEPTION;

     {

       EXCEPTION_MARK;

       this_oop->set_initialization_state_and_notify(initialization_error, THREAD);

       CLEAR_PENDING_EXCEPTION;   // ignore any exception thrown, class initialization error is thrown below

     }

     DTRACE_CLASSINIT_PROBE_WAIT(error, instanceKlass::cast(this_oop()), -1,wait);

     if (e->is_a(SystemDictionary::Error_klass())) {

       THROW_OOP(e());

     } else {

       JavaCallArguments args(e);

       THROW_ARG(vmSymbols::java_lang_ExceptionInInitializerError(),

                 vmSymbols::throwable_void_signature(),

                 &args);

     }

   }

   DTRACE_CLASSINIT_PROBE_WAIT(end, instanceKlass::cast(this_oop()), -1,wait);

 }

 // Note: implementation moved to static method to expose the this pointer.

 void instanceKlass::set_initialization_state_and_notify(ClassState state, TRAPS) {

   instanceKlassHandle kh(THREAD, this->as_klassOop());

   set_initialization_state_and_notify_impl(kh, state, CHECK);

 }

 void instanceKlass::set_initialization_state_and_notify_impl(instanceKlassHandle this_oop, ClassState state, TRAPS) {

   ObjectLocker ol(this_oop, THREAD);

   this_oop->set_init_state(state);

   ol.notify_all(CHECK);

 }

 void instanceKlass::add_implementor(klassOop k) {

   assert(Compile_lock->owned_by_self(), "");

   // Filter out my subinterfaces.

   // (Note: Interfaces are never on the subklass list.)

   if (instanceKlass::cast(k)->is_interface()) return;

   // Filter out subclasses whose supers already implement me.

   // (Note: CHA must walk subclasses of direct implementors

   // in order to locate indirect implementors.)

   klassOop sk = instanceKlass::cast(k)->super();

   if (sk != NULL && instanceKlass::cast(sk)->implements_interface(as_klassOop()))

     // We only need to check one immediate superclass, since the

     // implements_interface query looks at transitive_interfaces.

     // Any supers of the super have the same (or fewer) transitive_interfaces.

     return;

   // Update number of implementors

   int i = _nof_implementors++;

   // Record this implementor, if there are not too many already

   if (i < implementors_limit) {

     assert(_implementors[i] == NULL, "should be exactly one implementor");

     oop_store_without_check((oop*)&_implementors[i], k);

   } else if (i == implementors_limit) {

     // clear out the list on first overflow

     for (int i2 = 0; i2 < implementors_limit; i2++)

       oop_store_without_check((oop*)&_implementors[i2], NULL);

   }

   // The implementor also implements the transitive_interfaces

   for (int index = 0; index < local_interfaces()->length(); index++) {

     instanceKlass::cast(klassOop(local_interfaces()->obj_at(index)))->add_implementor(k);

   }

 }

 void instanceKlass::init_implementor() {

   for (int i = 0; i < implementors_limit; i++)

     oop_store_without_check((oop*)&_implementors[i], NULL);

   _nof_implementors = 0;

 }

 void instanceKlass::process_interfaces(Thread *thread) {

   // link this class into the implementors list of every interface it implements

   KlassHandle this_as_oop (thread, this->as_klassOop());

   for (int i = local_interfaces()->length() - 1; i >= 0; i--) {

     assert(local_interfaces()->obj_at(i)->is_klass(), "must be a klass");

     instanceKlass* interf = instanceKlass::cast(klassOop(local_interfaces()->obj_at(i)));

     assert(interf->is_interface(), "expected interface");

     interf->add_implementor(this_as_oop());

   }

 }

 bool instanceKlass::can_be_primary_super_slow() const {

   if (is_interface())

     return false;

   else

     return Klass::can_be_primary_super_slow();

 }

 objArrayOop instanceKlass::compute_secondary_supers(int num_extra_slots, TRAPS) {

   // The secondaries are the implemented interfaces.

   instanceKlass* ik = instanceKlass::cast(as_klassOop());

   objArrayHandle interfaces (THREAD, ik->transitive_interfaces());

   int num_secondaries = num_extra_slots + interfaces->length();

   if (num_secondaries == 0) {

     return Universe::the_empty_system_obj_array();

   } else if (num_extra_slots == 0) {

     return interfaces();

   } else {

     // a mix of both

     objArrayOop secondaries = oopFactory::new_system_objArray(num_secondaries, CHECK_NULL);

     for (int i = 0; i < interfaces->length(); i++) {

       secondaries->obj_at_put(num_extra_slots+i, interfaces->obj_at(i));

     }

     return secondaries;

   }

 }

 bool instanceKlass::compute_is_subtype_of(klassOop k) {

   if (Klass::cast(k)->is_interface()) {

     return implements_interface(k);

   } else {

     return Klass::compute_is_subtype_of(k);

   }

 }

 bool instanceKlass::implements_interface(klassOop k) const {

   if (as_klassOop() == k) return true;

   assert(Klass::cast(k)->is_interface(), "should be an interface class");

   for (int i = 0; i < transitive_interfaces()->length(); i++) {

     if (transitive_interfaces()->obj_at(i) == k) {

       return true;

     }

   }

   return false;

 }

 objArrayOop instanceKlass::allocate_objArray(int n, int length, TRAPS) {

   if (length < 0) THROW_0(vmSymbols::java_lang_NegativeArraySizeException());

   if (length > arrayOopDesc::max_array_length(T_OBJECT)) {

     report_java_out_of_memory("Requested array size exceeds VM limit");

     THROW_OOP_0(Universe::out_of_memory_error_array_size());

   }

   int size = objArrayOopDesc::object_size(length);

   klassOop ak = array_klass(n, CHECK_NULL);

   KlassHandle h_ak (THREAD, ak);

   objArrayOop o =

     (objArrayOop)CollectedHeap::array_allocate(h_ak, size, length, CHECK_NULL);

   return o;

 }

 instanceOop instanceKlass::register_finalizer(instanceOop i, TRAPS) {

   if (TraceFinalizerRegistration) {

     tty->print("Registered ");

     i->print_value_on(tty);

     tty->print_cr(" (" INTPTR_FORMAT ") as finalizable", (address)i);

   }

   instanceHandle h_i(THREAD, i);

   // Pass the handle as argument, JavaCalls::call expects oop as jobjects

   JavaValue result(T_VOID);

   JavaCallArguments args(h_i);

   methodHandle mh (THREAD, Universe::finalizer_register_method());

   JavaCalls::call(&result, mh, &args, CHECK_NULL);

   return h_i();

 }

 instanceOop instanceKlass::allocate_instance(TRAPS) {

   assert(!oop_is_instanceMirror(), "wrong allocation path");

   bool has_finalizer_flag = has_finalizer(); // Query before possible GC

   int size = size_helper();  // Query before forming handle.

   KlassHandle h_k(THREAD, as_klassOop());

   instanceOop i;

   i = (instanceOop)CollectedHeap::obj_allocate(h_k, size, CHECK_NULL);

   if (has_finalizer_flag && !RegisterFinalizersAtInit) {

     i = register_finalizer(i, CHECK_NULL);

   }

   return i;

 }

 instanceOop instanceKlass::allocate_permanent_instance(TRAPS) {

   // Finalizer registration occurs in the Object.<init> constructor

   // and constructors normally aren't run when allocating perm

   // instances so simply disallow finalizable perm objects.  This can

   // be relaxed if a need for it is found.

   assert(!has_finalizer(), "perm objects not allowed to have finalizers");

   assert(!oop_is_instanceMirror(), "wrong allocation path");

   int size = size_helper();  // Query before forming handle.

   KlassHandle h_k(THREAD, as_klassOop());

   instanceOop i = (instanceOop)

     CollectedHeap::permanent_obj_allocate(h_k, size, CHECK_NULL);

   return i;

 }

 void instanceKlass::check_valid_for_instantiation(bool throwError, TRAPS) {

   if (is_interface() || is_abstract()) {

     ResourceMark rm(THREAD);

     THROW_MSG(throwError ? vmSymbols::java_lang_InstantiationError()

               : vmSymbols::java_lang_InstantiationException(), external_name());

   }

   if (as_klassOop() == SystemDictionary::Class_klass()) {

     ResourceMark rm(THREAD);

     THROW_MSG(throwError ? vmSymbols::java_lang_IllegalAccessError()

               : vmSymbols::java_lang_IllegalAccessException(), external_name());

   }

 }

 klassOop instanceKlass::array_klass_impl(bool or_null, int n, TRAPS) {

   instanceKlassHandle this_oop(THREAD, as_klassOop());

   return array_klass_impl(this_oop, or_null, n, THREAD);

 }

 klassOop instanceKlass::array_klass_impl(instanceKlassHandle this_oop, bool or_null, int n, TRAPS) {

   if (this_oop->array_klasses() == NULL) {

     if (or_null) return NULL;

     ResourceMark rm;

     JavaThread *jt = (JavaThread *)THREAD;

     {

       // Atomic creation of array_klasses

       MutexLocker mc(Compile_lock, THREAD);   // for vtables

       MutexLocker ma(MultiArray_lock, THREAD);

       // Check if update has already taken place

       if (this_oop->array_klasses() == NULL) {

         objArrayKlassKlass* oakk =

           (objArrayKlassKlass*)Universe::objArrayKlassKlassObj()->klass_part();

         klassOop  k = oakk->allocate_objArray_klass(1, this_oop, CHECK_NULL);

         this_oop->set_array_klasses(k);

       }

     }

   }

   // _this will always be set at this point

   objArrayKlass* oak = (objArrayKlass*)this_oop->array_klasses()->klass_part();

   if (or_null) {

     return oak->array_klass_or_null(n);

   }

   return oak->array_klass(n, CHECK_NULL);

 }

 klassOop instanceKlass::array_klass_impl(bool or_null, TRAPS) {

   return array_klass_impl(or_null, 1, THREAD);

 }

 void instanceKlass::call_class_initializer(TRAPS) {

   instanceKlassHandle ik (THREAD, as_klassOop());

   call_class_initializer_impl(ik, THREAD);

 }

 static int call_class_initializer_impl_counter = 0;   // for debugging

 methodOop instanceKlass::class_initializer() {

   methodOop clinit = find_method(

       vmSymbols::class_initializer_name(), vmSymbols::void_method_signature());

   if (clinit != NULL && clinit->has_valid_initializer_flags()) {

     return clinit;

   }

   return NULL;

 }

 void instanceKlass::call_class_initializer_impl(instanceKlassHandle this_oop, TRAPS) {

   methodHandle h_method(THREAD, this_oop->class_initializer());

   assert(!this_oop->is_initialized(), "we cannot initialize twice");

   if (TraceClassInitialization) {

     tty->print("%d Initializing ", call_class_initializer_impl_counter++);

     this_oop->name()->print_value();

     tty->print_cr("%s (" INTPTR_FORMAT ")", h_method() == NULL ? "(no method)" : "", (address)this_oop());

   }

   if (h_method() != NULL) {

     JavaCallArguments args; // No arguments

     JavaValue result(T_VOID);

     JavaCalls::call(&result, h_method, &args, CHECK); // Static call (no args)

   }

 }

 void instanceKlass::mask_for(methodHandle method, int bci,

   InterpreterOopMap* entry_for) {

   // Dirty read, then double-check under a lock.

   if (_oop_map_cache == NULL) {

     // Otherwise, allocate a new one.

     MutexLocker x(OopMapCacheAlloc_lock);

     // First time use. Allocate a cache in C heap

     if (_oop_map_cache == NULL) {

       _oop_map_cache = new OopMapCache();

     }

   }

   // _oop_map_cache is constant after init; lookup below does is own locking.

   _oop_map_cache->lookup(method, bci, entry_for);

 }

 bool instanceKlass::find_local_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {

   for (JavaFieldStream fs(as_klassOop()); !fs.done(); fs.next()) {

     Symbol* f_name = fs.name();

     Symbol* f_sig  = fs.signature();

     if (f_name == name && f_sig == sig) {

       fd->initialize(as_klassOop(), fs.index());

       return true;

     }

   }

   return false;

 }

 void instanceKlass::shared_symbols_iterate(SymbolClosure* closure) {

   Klass::shared_symbols_iterate(closure);

   closure->do_symbol(&_generic_signature);

   closure->do_symbol(&_source_file_name);

   closure->do_symbol(&_source_debug_extension);

   for (JavaFieldStream fs(this); !fs.done(); fs.next()) {

     int name_index = fs.name_index();

     closure->do_symbol(constants()->symbol_at_addr(name_index));

     int sig_index  = fs.signature_index();

     closure->do_symbol(constants()->symbol_at_addr(sig_index));

   }

 }

 klassOop instanceKlass::find_interface_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {

   const int n = local_interfaces()->length();

   for (int i = 0; i < n; i++) {

     klassOop intf1 = klassOop(local_interfaces()->obj_at(i));

     assert(Klass::cast(intf1)->is_interface(), "just checking type");

     // search for field in current interface

     if (instanceKlass::cast(intf1)->find_local_field(name, sig, fd)) {

       assert(fd->is_static(), "interface field must be static");

       return intf1;

     }

     // search for field in direct superinterfaces

     klassOop intf2 = instanceKlass::cast(intf1)->find_interface_field(name, sig, fd);

     if (intf2 != NULL) return intf2;

   }

   // otherwise field lookup fails

   return NULL;

 }

 klassOop instanceKlass::find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {

   // search order according to newest JVM spec (5.4.3.2, p.167).

   // 1) search for field in current klass

   if (find_local_field(name, sig, fd)) {

     return as_klassOop();

   }

   // 2) search for field recursively in direct superinterfaces

   { klassOop intf = find_interface_field(name, sig, fd);

     if (intf != NULL) return intf;

   }

   // 3) apply field lookup recursively if superclass exists

   { klassOop supr = super();

     if (supr != NULL) return instanceKlass::cast(supr)->find_field(name, sig, fd);

   }

   // 4) otherwise field lookup fails

   return NULL;

 }

 klassOop instanceKlass::find_field(Symbol* name, Symbol* sig, bool is_static, fieldDescriptor* fd) const {

   // search order according to newest JVM spec (5.4.3.2, p.167).

   // 1) search for field in current klass

   if (find_local_field(name, sig, fd)) {

     if (fd->is_static() == is_static) return as_klassOop();

   }

   // 2) search for field recursively in direct superinterfaces

   if (is_static) {

     klassOop intf = find_interface_field(name, sig, fd);

     if (intf != NULL) return intf;

   }

   // 3) apply field lookup recursively if superclass exists

   { klassOop supr = super();

     if (supr != NULL) return instanceKlass::cast(supr)->find_field(name, sig, is_static, fd);

   }

   // 4) otherwise field lookup fails

   return NULL;

 }

 bool instanceKlass::find_local_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const {

   for (JavaFieldStream fs(as_klassOop()); !fs.done(); fs.next()) {

     if (fs.offset() == offset) {

       fd->initialize(as_klassOop(), fs.index());

       if (fd->is_static() == is_static) return true;

     }

   }

   return false;

 }

 bool instanceKlass::find_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const {

   klassOop klass = as_klassOop();

   while (klass != NULL) {

     if (instanceKlass::cast(klass)->find_local_field_from_offset(offset, is_static, fd)) {

       return true;

     }

     klass = Klass::cast(klass)->super();

   }

   return false;

 }

 void instanceKlass::methods_do(void f(methodOop method)) {

   int len = methods()->length();

   for (int index = 0; index < len; index++) {

     methodOop m = methodOop(methods()->obj_at(index));

     assert(m->is_method(), "must be method");

     f(m);

   }

 }

 void instanceKlass::do_local_static_fields(FieldClosure* cl) {

   for (JavaFieldStream fs(this); !fs.done(); fs.next()) {

     if (fs.access_flags().is_static()) {

       fieldDescriptor fd;

       fd.initialize(as_klassOop(), fs.index());

       cl->do_field(&fd);

     }

   }

 }

 void instanceKlass::do_local_static_fields(void f(fieldDescriptor*, TRAPS), TRAPS) {

   instanceKlassHandle h_this(THREAD, as_klassOop());

   do_local_static_fields_impl(h_this, f, CHECK);

 }

 void instanceKlass::do_local_static_fields_impl(instanceKlassHandle this_oop, void f(fieldDescriptor* fd, TRAPS), TRAPS) {

   for (JavaFieldStream fs(this_oop()); !fs.done(); fs.next()) {

     if (fs.access_flags().is_static()) {

       fieldDescriptor fd;

       fd.initialize(this_oop(), fs.index());

       f(&fd, CHECK);

     }

   }

 }

 static int compare_fields_by_offset(int* a, int* b) {

   return a[0] - b[0];

 }

 void instanceKlass::do_nonstatic_fields(FieldClosure* cl) {

   instanceKlass* super = superklass();

   if (super != NULL) {

     super->do_nonstatic_fields(cl);

   }

   fieldDescriptor fd;

   int length = java_fields_count();

   // In DebugInfo nonstatic fields are sorted by offset.

   int* fields_sorted = NEW_C_HEAP_ARRAY(int, 2*(length+1));

   int j = 0;

   for (int i = 0; i < length; i += 1) {

     fd.initialize(as_klassOop(), i);

     if (!fd.is_static()) {

       fields_sorted[j + 0] = fd.offset();

       fields_sorted[j + 1] = i;

       j += 2;

     }

   }

   if (j > 0) {

     length = j;

     // _sort_Fn is defined in growableArray.hpp.

     qsort(fields_sorted, length/2, 2*sizeof(int), (_sort_Fn)compare_fields_by_offset);

     for (int i = 0; i < length; i += 2) {

       fd.initialize(as_klassOop(), fields_sorted[i + 1]);

       assert(!fd.is_static() && fd.offset() == fields_sorted[i], "only nonstatic fields");

       cl->do_field(&fd);

     }

   }

   FREE_C_HEAP_ARRAY(int, fields_sorted);

 }

 void instanceKlass::array_klasses_do(void f(klassOop k)) {

   if (array_klasses() != NULL)

     arrayKlass::cast(array_klasses())->array_klasses_do(f);

 }

 void instanceKlass::with_array_klasses_do(void f(klassOop k)) {

   f(as_klassOop());

   array_klasses_do(f);

 }

 #ifdef ASSERT

 static int linear_search(objArrayOop methods, Symbol* name, Symbol* signature) {

   int len = methods->length();

   for (int index = 0; index < len; index++) {

     methodOop m = (methodOop)(methods->obj_at(index));

     assert(m->is_method(), "must be method");

     if (m->signature() == signature && m->name() == name) {

        return index;

     }

   }

   return -1;

 }

 #endif

 methodOop instanceKlass::find_method(Symbol* name, Symbol* signature) const {

   return instanceKlass::find_method(methods(), name, signature);

 }

 methodOop instanceKlass::find_method(objArrayOop methods, Symbol* name, Symbol* signature) {

   int len = methods->length();

   // methods are sorted, so do binary search

   int l = 0;

   int h = len - 1;

   while (l <= h) {

     int mid = (l + h) >> 1;

     methodOop m = (methodOop)methods->obj_at(mid);

     assert(m->is_method(), "must be method");

     int res = m->name()->fast_compare(name);

     if (res == 0) {

       // found matching name; do linear search to find matching signature

       // first, quick check for common case

       if (m->signature() == signature) return m;

       // search downwards through overloaded methods

       int i;

       for (i = mid - 1; i >= l; i--) {

         methodOop m = (methodOop)methods->obj_at(i);

         assert(m->is_method(), "must be method");

         if (m->name() != name) break;

         if (m->signature() == signature) return m;

       }

       // search upwards

       for (i = mid + 1; i <= h; i++) {

         methodOop m = (methodOop)methods->obj_at(i);

         assert(m->is_method(), "must be method");

         if (m->name() != name) break;

         if (m->signature() == signature) return m;

       }

       // not found

 #ifdef ASSERT

       int index = linear_search(methods, name, signature);

       assert(index == -1, err_msg("binary search should have found entry %d", index));

 #endif

       return NULL;

     } else if (res < 0) {

       l = mid + 1;

     } else {

       h = mid - 1;

     }

   }

 #ifdef ASSERT

   int index = linear_search(methods, name, signature);

   assert(index == -1, err_msg("binary search should have found entry %d", index));

 #endif

   return NULL;

 }

 methodOop instanceKlass::uncached_lookup_method(Symbol* name, Symbol* signature) const {

   klassOop klass = as_klassOop();

   while (klass != NULL) {

     methodOop method = instanceKlass::cast(klass)->find_method(name, signature);

     if (method != NULL) return method;

     klass = instanceKlass::cast(klass)->super();

   }

   return NULL;

 }

 // lookup a method in all the interfaces that this class implements

 methodOop instanceKlass::lookup_method_in_all_interfaces(Symbol* name,

                                                          Symbol* signature) const {

   objArrayOop all_ifs = instanceKlass::cast(as_klassOop())->transitive_interfaces();

   int num_ifs = all_ifs->length();

   instanceKlass *ik = NULL;

   for (int i = 0; i < num_ifs; i++) {

     ik = instanceKlass::cast(klassOop(all_ifs->obj_at(i)));

     methodOop m = ik->lookup_method(name, signature);

     if (m != NULL) {

       return m;

     }

   }

   return NULL;

 }

 /* jni_id_for_impl for jfieldIds only */

 JNIid* instanceKlass::jni_id_for_impl(instanceKlassHandle this_oop, int offset) {

   MutexLocker ml(JfieldIdCreation_lock);

   // Retry lookup after we got the lock

   JNIid* probe = this_oop->jni_ids() == NULL ? NULL : this_oop->jni_ids()->find(offset);

   if (probe == NULL) {

     // Slow case, allocate new static field identifier

     probe = new JNIid(this_oop->as_klassOop(), offset, this_oop->jni_ids());

     this_oop->set_jni_ids(probe);

   }

   return probe;

 }

 /* jni_id_for for jfieldIds only */

 JNIid* instanceKlass::jni_id_for(int offset) {

   JNIid* probe = jni_ids() == NULL ? NULL : jni_ids()->find(offset);

   if (probe == NULL) {

     probe = jni_id_for_impl(this->as_klassOop(), offset);

   }

   return probe;

 }

 u2 instanceKlass::enclosing_method_data(int offset) {

   typeArrayOop inner_class_list = inner_classes();

   if (inner_class_list == NULL) {

     return 0;

   }

   int length = inner_class_list->length();

   if (length % inner_class_next_offset == 0) {

     return 0;

   } else {

     int index = length - enclosing_method_attribute_size;

     typeArrayHandle inner_class_list_h(inner_class_list);

     assert(offset < enclosing_method_attribute_size, "invalid offset");

     return inner_class_list_h->ushort_at(index + offset);

   }

 }

 void instanceKlass::set_enclosing_method_indices(u2 class_index,

                                                  u2 method_index) {

   typeArrayOop inner_class_list = inner_classes();

   assert (inner_class_list != NULL, "_inner_classes list is not set up");

   int length = inner_class_list->length();

   if (length % inner_class_next_offset == enclosing_method_attribute_size) {

     int index = length - enclosing_method_attribute_size;

     typeArrayHandle inner_class_list_h(inner_class_list);

     inner_class_list_h->ushort_at_put(

       index + enclosing_method_class_index_offset, class_index);

     inner_class_list_h->ushort_at_put(

       index + enclosing_method_method_index_offset, method_index);

   }

 }

 // Lookup or create a jmethodID.

 // This code is called by the VMThread and JavaThreads so the

 // locking has to be done very carefully to avoid deadlocks

 // and/or other cache consistency problems.

 //

 jmethodID instanceKlass::get_jmethod_id(instanceKlassHandle ik_h, methodHandle method_h) {

   size_t idnum = (size_t)method_h->method_idnum();

   jmethodID* jmeths = ik_h->methods_jmethod_ids_acquire();

   size_t length = 0;

   jmethodID id = NULL;

   // We use a double-check locking idiom here because this cache is

   // performance sensitive. In the normal system, this cache only

   // transitions from NULL to non-NULL which is safe because we use

   // release_set_methods_jmethod_ids() to advertise the new cache.

   // A partially constructed cache should never be seen by a racing

   // thread. We also use release_store_ptr() to save a new jmethodID

   // in the cache so a partially constructed jmethodID should never be

   // seen either. Cache reads of existing jmethodIDs proceed without a

   // lock, but cache writes of a new jmethodID requires uniqueness and

   // creation of the cache itself requires no leaks so a lock is

   // generally acquired in those two cases.

   //

   // If the RedefineClasses() API has been used, then this cache can

   // grow and we'll have transitions from non-NULL to bigger non-NULL.

   // Cache creation requires no leaks and we require safety between all

   // cache accesses and freeing of the old cache so a lock is generally

   // acquired when the RedefineClasses() API has been used.

   if (jmeths != NULL) {

     // the cache already exists

     if (!ik_h->idnum_can_increment()) {

       // the cache can't grow so we can just get the current values

       get_jmethod_id_length_value(jmeths, idnum, &length, &id);

     } else {

       // cache can grow so we have to be more careful

       if (Threads::number_of_threads() == 0 ||

           SafepointSynchronize::is_at_safepoint()) {

         // we're single threaded or at a safepoint - no locking needed

         get_jmethod_id_length_value(jmeths, idnum, &length, &id);

       } else {

         MutexLocker ml(JmethodIdCreation_lock);

         get_jmethod_id_length_value(jmeths, idnum, &length, &id);

       }

     }

   }

   // implied else:

   // we need to allocate a cache so default length and id values are good

   if (jmeths == NULL ||   // no cache yet

       length <= idnum ||  // cache is too short

       id == NULL) {       // cache doesn't contain entry

     // This function can be called by the VMThread so we have to do all

     // things that might block on a safepoint before grabbing the lock.

     // Otherwise, we can deadlock with the VMThread or have a cache

     // consistency issue. These vars keep track of what we might have

     // to free after the lock is dropped.

     jmethodID  to_dealloc_id     = NULL;

     jmethodID* to_dealloc_jmeths = NULL;

     // may not allocate new_jmeths or use it if we allocate it

     jmethodID* new_jmeths = NULL;

     if (length <= idnum) {

       // allocate a new cache that might be used

       size_t size = MAX2(idnum+1, (size_t)ik_h->idnum_allocated_count());

       new_jmeths = NEW_C_HEAP_ARRAY(jmethodID, size+1);

       memset(new_jmeths, 0, (size+1)*sizeof(jmethodID));

       // cache size is stored in element[0], other elements offset by one

       new_jmeths[0] = (jmethodID)size;

     }

     // allocate a new jmethodID that might be used

     jmethodID new_id = NULL;

     if (method_h->is_old() && !method_h->is_obsolete()) {

       // The method passed in is old (but not obsolete), we need to use the current version

       methodOop current_method = ik_h->method_with_idnum((int)idnum);

       assert(current_method != NULL, "old and but not obsolete, so should exist");

       methodHandle current_method_h(current_method == NULL? method_h() : current_method);

       new_id = JNIHandles::make_jmethod_id(current_method_h);

     } else {

       // It is the current version of the method or an obsolete method,

       // use the version passed in

       new_id = JNIHandles::make_jmethod_id(method_h);

     }

     if (Threads::number_of_threads() == 0 ||

         SafepointSynchronize::is_at_safepoint()) {

       // we're single threaded or at a safepoint - no locking needed

       id = get_jmethod_id_fetch_or_update(ik_h, idnum, new_id, new_jmeths,

                                           &to_dealloc_id, &to_dealloc_jmeths);

     } else {

       MutexLocker ml(JmethodIdCreation_lock);

       id = get_jmethod_id_fetch_or_update(ik_h, idnum, new_id, new_jmeths,

                                           &to_dealloc_id, &to_dealloc_jmeths);

     }

     // The lock has been dropped so we can free resources.

     // Free up either the old cache or the new cache if we allocated one.

     if (to_dealloc_jmeths != NULL) {

       FreeHeap(to_dealloc_jmeths);

     }

     // free up the new ID since it wasn't needed

     if (to_dealloc_id != NULL) {

       JNIHandles::destroy_jmethod_id(to_dealloc_id);

     }

   }

   return id;

 }

 // Common code to fetch the jmethodID from the cache or update the

 // cache with the new jmethodID. This function should never do anything

 // that causes the caller to go to a safepoint or we can deadlock with

 // the VMThread or have cache consistency issues.

 //

 jmethodID instanceKlass::get_jmethod_id_fetch_or_update(

             instanceKlassHandle ik_h, size_t idnum, jmethodID new_id,

             jmethodID* new_jmeths, jmethodID* to_dealloc_id_p,

             jmethodID** to_dealloc_jmeths_p) {

   assert(new_id != NULL, "sanity check");

   assert(to_dealloc_id_p != NULL, "sanity check");

   assert(to_dealloc_jmeths_p != NULL, "sanity check");

   assert(Threads::number_of_threads() == 0 ||

          SafepointSynchronize::is_at_safepoint() ||

          JmethodIdCreation_lock->owned_by_self(), "sanity check");

   // reacquire the cache - we are locked, single threaded or at a safepoint

   jmethodID* jmeths = ik_h->methods_jmethod_ids_acquire();

   jmethodID  id     = NULL;

   size_t     length = 0;

   if (jmeths == NULL ||                         // no cache yet

       (length = (size_t)jmeths[0]) <= idnum) {  // cache is too short

     if (jmeths != NULL) {

       // copy any existing entries from the old cache

       for (size_t index = 0; index < length; index++) {

         new_jmeths[index+1] = jmeths[index+1];

       }

       *to_dealloc_jmeths_p = jmeths;  // save old cache for later delete

     }

     ik_h->release_set_methods_jmethod_ids(jmeths = new_jmeths);

   } else {

     // fetch jmethodID (if any) from the existing cache

     id = jmeths[idnum+1];

     *to_dealloc_jmeths_p = new_jmeths;  // save new cache for later delete

   }

   if (id == NULL) {

     // No matching jmethodID in the existing cache or we have a new

     // cache or we just grew the cache. This cache write is done here

     // by the first thread to win the foot race because a jmethodID

     // needs to be unique once it is generally available.

     id = new_id;

     // The jmethodID cache can be read while unlocked so we have to

     // make sure the new jmethodID is complete before installing it

     // in the cache.

     OrderAccess::release_store_ptr(&jmeths[idnum+1], id);

   } else {

     *to_dealloc_id_p = new_id; // save new id for later delete

   }

   return id;

 }

 // Common code to get the jmethodID cache length and the jmethodID

 // value at index idnum if there is one.

 //

 void instanceKlass::get_jmethod_id_length_value(jmethodID* cache,

        size_t idnum, size_t *length_p, jmethodID* id_p) {

   assert(cache != NULL, "sanity check");

   assert(length_p != NULL, "sanity check");

   assert(id_p != NULL, "sanity check");

   // cache size is stored in element[0], other elements offset by one

   *length_p = (size_t)cache[0];

   if (*length_p <= idnum) {  // cache is too short

     *id_p = NULL;

   } else {

     *id_p = cache[idnum+1];  // fetch jmethodID (if any)

   }

 }

 // Lookup a jmethodID, NULL if not found.  Do no blocking, no allocations, no handles

 jmethodID instanceKlass::jmethod_id_or_null(methodOop method) {

   size_t idnum = (size_t)method->method_idnum();

   jmethodID* jmeths = methods_jmethod_ids_acquire();

   size_t length;                                // length assigned as debugging crumb

   jmethodID id = NULL;

   if (jmeths != NULL &&                         // If there is a cache

       (length = (size_t)jmeths[0]) > idnum) {   // and if it is long enough,

     id = jmeths[idnum+1];                       // Look up the id (may be NULL)

   }

   return id;

 }

 // Cache an itable index

 void instanceKlass::set_cached_itable_index(size_t idnum, int index) {

   int* indices = methods_cached_itable_indices_acquire();

   int* to_dealloc_indices = NULL;

   // We use a double-check locking idiom here because this cache is

   // performance sensitive. In the normal system, this cache only

   // transitions from NULL to non-NULL which is safe because we use

   // release_set_methods_cached_itable_indices() to advertise the

   // new cache. A partially constructed cache should never be seen

   // by a racing thread. Cache reads and writes proceed without a

   // lock, but creation of the cache itself requires no leaks so a

   // lock is generally acquired in that case.

   //

   // If the RedefineClasses() API has been used, then this cache can

   // grow and we'll have transitions from non-NULL to bigger non-NULL.

   // Cache creation requires no leaks and we require safety between all

   // cache accesses and freeing of the old cache so a lock is generally

   // acquired when the RedefineClasses() API has been used.

   if (indices == NULL || idnum_can_increment()) {

     // we need a cache or the cache can grow

     MutexLocker ml(JNICachedItableIndex_lock);

     // reacquire the cache to see if another thread already did the work

     indices = methods_cached_itable_indices_acquire();

     size_t length = 0;

     // cache size is stored in element[0], other elements offset by one

     if (indices == NULL || (length = (size_t)indices[0]) <= idnum) {

       size_t size = MAX2(idnum+1, (size_t)idnum_allocated_count());

       int* new_indices = NEW_C_HEAP_ARRAY(int, size+1);

       new_indices[0] = (int)size;

       // copy any existing entries

       size_t i;

       for (i = 0; i < length; i++) {

         new_indices[i+1] = indices[i+1];

       }

       // Set all the rest to -1

       for (i = length; i < size; i++) {

         new_indices[i+1] = -1;

       }

       if (indices != NULL) {

         // We have an old cache to delete so save it for after we

         // drop the lock.

         to_dealloc_indices = indices;

       }

       release_set_methods_cached_itable_indices(indices = new_indices);

     }

     if (idnum_can_increment()) {

       // this cache can grow so we have to write to it safely

       indices[idnum+1] = index;

     }

   } else {

     CHECK_UNHANDLED_OOPS_ONLY(Thread::current()->clear_unhandled_oops());

   }

   if (!idnum_can_increment()) {

     // The cache cannot grow and this JNI itable index value does not

     // have to be unique like a jmethodID. If there is a race to set it,

     // it doesn't matter.

     indices[idnum+1] = index;

   }

   if (to_dealloc_indices != NULL) {

     // we allocated a new cache so free the old one

     FreeHeap(to_dealloc_indices);

   }

 }

 // Retrieve a cached itable index

 int instanceKlass::cached_itable_index(size_t idnum) {

   int* indices = methods_cached_itable_indices_acquire();

   if (indices != NULL && ((size_t)indices[0]) > idnum) {

      // indices exist and are long enough, retrieve possible cached

     return indices[idnum+1];

   }

   return -1;

 }

 //

 // Walk the list of dependent nmethods searching for nmethods which

 // are dependent on the changes that were passed in and mark them for

 // deoptimization.  Returns the number of nmethods found.

 //

 int instanceKlass::mark_dependent_nmethods(DepChange& changes) {

   assert_locked_or_safepoint(CodeCache_lock);

   int found = 0;

   nmethodBucket* b = _dependencies;

   while (b != NULL) {

     nmethod* nm = b->get_nmethod();

     // since dependencies aren't removed until an nmethod becomes a zombie,

     // the dependency list may contain nmethods which aren't alive.

     if (nm->is_alive() && !nm->is_marked_for_deoptimization() && nm->check_dependency_on(changes)) {

       if (TraceDependencies) {

         ResourceMark rm;

         tty->print_cr("Marked for deoptimization");

         tty->print_cr("  context = %s", this->external_name());

         changes.print();

         nm->print();

         nm->print_dependencies();

       }

       nm->mark_for_deoptimization();

       found++;

     }

     b = b->next();

   }

   return found;

 }

 //

 // Add an nmethodBucket to the list of dependencies for this nmethod.

 // It's possible that an nmethod has multiple dependencies on this klass

 // so a count is kept for each bucket to guarantee that creation and

 // deletion of dependencies is consistent.

 //

 void instanceKlass::add_dependent_nmethod(nmethod* nm) {

   assert_locked_or_safepoint(CodeCache_lock);

   nmethodBucket* b = _dependencies;

   nmethodBucket* last = NULL;

   while (b != NULL) {

     if (nm == b->get_nmethod()) {

       b->increment();

       return;

     }

     b = b->next();

   }

   _dependencies = new nmethodBucket(nm, _dependencies);

 }

 //

 // Decrement count of the nmethod in the dependency list and remove

 // the bucket competely when the count goes to 0.  This method must

 // find a corresponding bucket otherwise there's a bug in the

 // recording of dependecies.

 //

 void instanceKlass::remove_dependent_nmethod(nmethod* nm) {

   assert_locked_or_safepoint(CodeCache_lock);

   nmethodBucket* b = _dependencies;

   nmethodBucket* last = NULL;

   while (b != NULL) {

     if (nm == b->get_nmethod()) {

       if (b->decrement() == 0) {

         if (last == NULL) {

           _dependencies = b->next();

         } else {

           last->set_next(b->next());

         }

         delete b;

       }

       return;

     }

     last = b;

     b = b->next();

   }

 #ifdef ASSERT

   tty->print_cr("### %s can't find dependent nmethod:", this->external_name());

   nm->print();

 #endif // ASSERT

   ShouldNotReachHere();

 }

 #ifndef PRODUCT

 void instanceKlass::print_dependent_nmethods(bool verbose) {

   nmethodBucket* b = _dependencies;

   int idx = 0;

   while (b != NULL) {

     nmethod* nm = b->get_nmethod();

     tty->print("[%d] count=%d { ", idx++, b->count());

     if (!verbose) {

       nm->print_on(tty, "nmethod");

       tty->print_cr(" } ");

     } else {

       nm->print();

       nm->print_dependencies();

       tty->print_cr("--- } ");

     }

     b = b->next();

   }

 }

 bool instanceKlass::is_dependent_nmethod(nmethod* nm) {

   nmethodBucket* b = _dependencies;

   while (b != NULL) {

     if (nm == b->get_nmethod()) {

       return true;

     }

     b = b->next();

   }

   return false;

 }

 #endif //PRODUCT

 #ifdef ASSERT

 template <class T> void assert_is_in(T *p) {

   T heap_oop = oopDesc::load_heap_oop(p);

   if (!oopDesc::is_null(heap_oop)) {

     oop o = oopDesc::decode_heap_oop_not_null(heap_oop);

     assert(Universe::heap()->is_in(o), "should be in heap");

   }

 }

 template <class T> void assert_is_in_closed_subset(T *p) {

   T heap_oop = oopDesc::load_heap_oop(p);

   if (!oopDesc::is_null(heap_oop)) {

     oop o = oopDesc::decode_heap_oop_not_null(heap_oop);

     assert(Universe::heap()->is_in_closed_subset(o), "should be in closed");

   }

 }

 template <class T> void assert_is_in_reserved(T *p) {

   T heap_oop = oopDesc::load_heap_oop(p);

   if (!oopDesc::is_null(heap_oop)) {

     oop o = oopDesc::decode_heap_oop_not_null(heap_oop);

     assert(Universe::heap()->is_in_reserved(o), "should be in reserved");

   }

 }

 template <class T> void assert_nothing(T *p) {}

 #else

 template <class T> void assert_is_in(T *p) {}

 template <class T> void assert_is_in_closed_subset(T *p) {}

 template <class T> void assert_is_in_reserved(T *p) {}

 template <class T> void assert_nothing(T *p) {}

 #endif // ASSERT

 //

 // Macros that iterate over areas of oops which are specialized on type of

 // oop pointer either narrow or wide, depending on UseCompressedOops

 //

 // Parameters are:

 //   T         - type of oop to point to (either oop or narrowOop)

 //   start_p   - starting pointer for region to iterate over

 //   count     - number of oops or narrowOops to iterate over

 //   do_oop    - action to perform on each oop (it's arbitrary C code which

 //               makes it more efficient to put in a macro rather than making

 //               it a template function)

 //   assert_fn - assert function which is template function because performance

 //               doesn't matter when enabled.

 #define InstanceKlass_SPECIALIZED_OOP_ITERATE( \

   T, start_p, count, do_oop,                \

   assert_fn)                                \

 {                                           \

   T* p         = (T*)(start_p);             \

   T* const end = p + (count);               \

   while (p < end) {                         \

     (assert_fn)(p);                         \

     do_oop;                                 \

     ++p;                                    \

   }                                         \

 }

 #define InstanceKlass_SPECIALIZED_OOP_REVERSE_ITERATE( \

   T, start_p, count, do_oop,                \

   assert_fn)                                \

 {                                           \

   T* const start = (T*)(start_p);           \

   T*       p     = start + (count);         \

   while (start < p) {                       \

     --p;                                    \

     (assert_fn)(p);                         \

     do_oop;                                 \

   }                                         \

 }

 #define InstanceKlass_SPECIALIZED_BOUNDED_OOP_ITERATE( \

   T, start_p, count, low, high,             \

   do_oop, assert_fn)                        \

 {                                           \

   T* const l = (T*)(low);                   \

   T* const h = (T*)(high);                  \

   assert(mask_bits((intptr_t)l, sizeof(T)-1) == 0 && \

          mask_bits((intptr_t)h, sizeof(T)-1) == 0,   \

          "bounded region must be properly aligned"); \

   T* p       = (T*)(start_p);               \

   T* end     = p + (count);                 \

   if (p < l) p = l;                         \

   if (end > h) end = h;                     \

   while (p < end) {                         \

     (assert_fn)(p);                         \

     do_oop;                                 \

     ++p;                                    \

   }                                         \

 }

 // The following macros call specialized macros, passing either oop or

 // narrowOop as the specialization type.  These test the UseCompressedOops

 // flag.

 #define InstanceKlass_OOP_MAP_ITERATE(obj, do_oop, assert_fn)            \

 {                                                                        \

   /* Compute oopmap block range. The common case                         \

      is nonstatic_oop_map_size == 1. */                                  \

   OopMapBlock* map           = start_of_nonstatic_oop_maps();            \

   OopMapBlock* const end_map = map + nonstatic_oop_map_count();          \

   if (UseCompressedOops) {                                               \

     while (map < end_map) {                                              \

       InstanceKlass_SPECIALIZED_OOP_ITERATE(narrowOop,                   \

         obj->obj_field_addr<narrowOop>(map->offset()), map->count(),     \

         do_oop, assert_fn)                                               \

       ++map;                                                             \

     }                                                                    \

   } else {                                                               \

     while (map < end_map) {                                              \

       InstanceKlass_SPECIALIZED_OOP_ITERATE(oop,                         \

         obj->obj_field_addr<oop>(map->offset()), map->count(),           \

         do_oop, assert_fn)                                               \

       ++map;                                                             \

     }                                                                    \

   }                                                                      \

 }

 #define InstanceKlass_OOP_MAP_REVERSE_ITERATE(obj, do_oop, assert_fn)    \

 {                                                                        \

   OopMapBlock* const start_map = start_of_nonstatic_oop_maps();          \

   OopMapBlock* map             = start_map + nonstatic_oop_map_count();  \

   if (UseCompressedOops) {                                               \

     while (start_map < map) {                                            \

       --map;                                                             \

       InstanceKlass_SPECIALIZED_OOP_REVERSE_ITERATE(narrowOop,           \

         obj->obj_field_addr<narrowOop>(map->offset()), map->count(),     \

         do_oop, assert_fn)                                               \

     }                                                                    \

   } else {                                                               \

     while (start_map < map) {                                            \

       --map;                                                             \

       InstanceKlass_SPECIALIZED_OOP_REVERSE_ITERATE(oop,                 \

         obj->obj_field_addr<oop>(map->offset()), map->count(),           \

         do_oop, assert_fn)                                               \

     }                                                                    \

   }                                                                      \

 }

 #define InstanceKlass_BOUNDED_OOP_MAP_ITERATE(obj, low, high, do_oop,    \

                                               assert_fn)                 \

 {                                                                        \

   /* Compute oopmap block range. The common case is                      \

      nonstatic_oop_map_size == 1, so we accept the                       \

      usually non-existent extra overhead of examining                    \

      all the maps. */                                                    \

   OopMapBlock* map           = start_of_nonstatic_oop_maps();            \

   OopMapBlock* const end_map = map + nonstatic_oop_map_count();          \

   if (UseCompressedOops) {                                               \

     while (map < end_map) {                                              \

       InstanceKlass_SPECIALIZED_BOUNDED_OOP_ITERATE(narrowOop,           \

         obj->obj_field_addr<narrowOop>(map->offset()), map->count(),     \

         low, high,                                                       \

         do_oop, assert_fn)                                               \

       ++map;                                                             \

     }                                                                    \

   } else {                                                               \

     while (map < end_map) {                                              \

       InstanceKlass_SPECIALIZED_BOUNDED_OOP_ITERATE(oop,                 \

         obj->obj_field_addr<oop>(map->offset()), map->count(),           \

         low, high,                                                       \

         do_oop, assert_fn)                                               \

       ++map;                                                             \

     }                                                                    \

   }                                                                      \

 }

 void instanceKlass::oop_follow_contents(oop obj) {

   assert(obj != NULL, "can't follow the content of NULL object");

   obj->follow_header();

   InstanceKlass_OOP_MAP_ITERATE( \

     obj, \

     MarkSweep::mark_and_push(p), \

     assert_is_in_closed_subset)

 }

 #ifndef SERIALGC

 void instanceKlass::oop_follow_contents(ParCompactionManager* cm,

                                         oop obj) {

   assert(obj != NULL, "can't follow the content of NULL object");

   obj->follow_header(cm);

   InstanceKlass_OOP_MAP_ITERATE( \

     obj, \

     PSParallelCompact::mark_and_push(cm, p), \

     assert_is_in)

 }

 #endif // SERIALGC

 // closure's do_header() method dicates whether the given closure should be

 // applied to the klass ptr in the object header.

 #define InstanceKlass_OOP_OOP_ITERATE_DEFN(OopClosureType, nv_suffix)        \

                                                                              \

 int instanceKlass::oop_oop_iterate##nv_suffix(oop obj, OopClosureType* closure) { \

   SpecializationStats::record_iterate_call##nv_suffix(SpecializationStats::ik);\

   /* header */                                                          \

   if (closure->do_header()) {                                           \

     obj->oop_iterate_header(closure);                                   \

   }                                                                     \

   InstanceKlass_OOP_MAP_ITERATE(                                        \

     obj,                                                                \

     SpecializationStats::                                               \

       record_do_oop_call##nv_suffix(SpecializationStats::ik);           \

     (closure)->do_oop##nv_suffix(p),                                    \

     assert_is_in_closed_subset)                                         \

   return size_helper();                                                 \

 }

 #ifndef SERIALGC

 #define InstanceKlass_OOP_OOP_ITERATE_BACKWARDS_DEFN(OopClosureType, nv_suffix) \

                                                                                 \

 int instanceKlass::oop_oop_iterate_backwards##nv_suffix(oop obj,                \

                                               OopClosureType* closure) {        \

   SpecializationStats::record_iterate_call##nv_suffix(SpecializationStats::ik); \

   /* header */                                                                  \

   if (closure->do_header()) {                                                   \

     obj->oop_iterate_header(closure);                                           \

   }                                                                             \

   /* instance variables */                                                      \

   InstanceKlass_OOP_MAP_REVERSE_ITERATE(                                        \

     obj,                                                                        \

     SpecializationStats::record_do_oop_call##nv_suffix(SpecializationStats::ik);\

     (closure)->do_oop##nv_suffix(p),                                            \

     assert_is_in_closed_subset)                                                 \

    return size_helper();                                                        \

 }

 #endif // !SERIALGC

 #define InstanceKlass_OOP_OOP_ITERATE_DEFN_m(OopClosureType, nv_suffix) \

                                                                         \

 int instanceKlass::oop_oop_iterate##nv_suffix##_m(oop obj,              \

                                                   OopClosureType* closure, \

                                                   MemRegion mr) {          \

   SpecializationStats::record_iterate_call##nv_suffix(SpecializationStats::ik);\

   if (closure->do_header()) {                                            \

     obj->oop_iterate_header(closure, mr);                                \

   }                                                                      \

   InstanceKlass_BOUNDED_OOP_MAP_ITERATE(                                 \

     obj, mr.start(), mr.end(),                                           \

     (closure)->do_oop##nv_suffix(p),                                     \

     assert_is_in_closed_subset)                                          \

   return size_helper();                                                  \

 }

 ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceKlass_OOP_OOP_ITERATE_DEFN)

 ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceKlass_OOP_OOP_ITERATE_DEFN)

 ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceKlass_OOP_OOP_ITERATE_DEFN_m)

 ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceKlass_OOP_OOP_ITERATE_DEFN_m)

 #ifndef SERIALGC

 ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceKlass_OOP_OOP_ITERATE_BACKWARDS_DEFN)

 ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceKlass_OOP_OOP_ITERATE_BACKWARDS_DEFN)

 #endif // !SERIALGC

 int instanceKlass::oop_adjust_pointers(oop obj) {

   int size = size_helper();

   InstanceKlass_OOP_MAP_ITERATE( \

     obj, \

     MarkSweep::adjust_pointer(p), \

     assert_is_in)

   obj->adjust_header();

   return size;

 }

 #ifndef SERIALGC

 void instanceKlass::oop_push_contents(PSPromotionManager* pm, oop obj) {

   InstanceKlass_OOP_MAP_REVERSE_ITERATE( \

     obj, \

     if (PSScavenge::should_scavenge(p)) { \

       pm->claim_or_forward_depth(p); \

     }, \

     assert_nothing )

 }

 int instanceKlass::oop_update_pointers(ParCompactionManager* cm, oop obj) {

   InstanceKlass_OOP_MAP_ITERATE( \

     obj, \

     PSParallelCompact::adjust_pointer(p), \

     assert_nothing)

   return size_helper();

 }

 #endif // SERIALGC

 // This klass is alive but the implementor link is not followed/updated.

 // Subklass and sibling links are handled by Klass::follow_weak_klass_links

 void instanceKlass::follow_weak_klass_links(

   BoolObjectClosure* is_alive, OopClosure* keep_alive) {

   assert(is_alive->do_object_b(as_klassOop()), "this oop should be live");

   if (ClassUnloading) {

     for (int i = 0; i < implementors_limit; i++) {

       klassOop impl = _implementors[i];

       if (impl == NULL)  break;  // no more in the list

       if (!is_alive->do_object_b(impl)) {

         // remove this guy from the list by overwriting him with the tail

         int lasti = --_nof_implementors;

         assert(lasti >= i && lasti < implementors_limit, "just checking");

         _implementors[i] = _implementors[lasti];

         _implementors[lasti] = NULL;

         --i; // rerun the loop at this index

       }

     }

   } else {

     for (int i = 0; i < implementors_limit; i++) {

       keep_alive->do_oop(&adr_implementors()[i]);

     }

   }

   Klass::follow_weak_klass_links(is_alive, keep_alive);

 }

 void instanceKlass::remove_unshareable_info() {

   Klass::remove_unshareable_info();

   init_implementor();

 }

 static void clear_all_breakpoints(methodOop m) {

   m->clear_all_breakpoints();

 }

 void instanceKlass::release_C_heap_structures() {

   // Deallocate oop map cache

   if (_oop_map_cache != NULL) {

     delete _oop_map_cache;

     _oop_map_cache = NULL;

   }

   // Deallocate JNI identifiers for jfieldIDs

   JNIid::deallocate(jni_ids());

   set_jni_ids(NULL);

   jmethodID* jmeths = methods_jmethod_ids_acquire();

   if (jmeths != (jmethodID*)NULL) {

     release_set_methods_jmethod_ids(NULL);

     FreeHeap(jmeths);

   }

   int* indices = methods_cached_itable_indices_acquire();

   if (indices != (int*)NULL) {

     release_set_methods_cached_itable_indices(NULL);

     FreeHeap(indices);

   }

   // release dependencies

   nmethodBucket* b = _dependencies;

   _dependencies = NULL;

   while (b != NULL) {

     nmethodBucket* next = b->next();

     delete b;

     b = next;

   }

   // Deallocate breakpoint records

   if (breakpoints() != 0x0) {

     methods_do(clear_all_breakpoints);

     assert(breakpoints() == 0x0, "should have cleared breakpoints");

   }

   // deallocate information about previous versions

   if (_previous_versions != NULL) {

     for (int i = _previous_versions->length() - 1; i >= 0; i--) {

       PreviousVersionNode * pv_node = _previous_versions->at(i);

       delete pv_node;

     }

     delete _previous_versions;

     _previous_versions = NULL;

   }

   // deallocate the cached class file

   if (_cached_class_file_bytes != NULL) {

     os::free(_cached_class_file_bytes);

     _cached_class_file_bytes = NULL;

     _cached_class_file_len = 0;

   }

   // Decrement symbol reference counts associated with the unloaded class.

   if (_name != NULL) _name->decrement_refcount();

   // unreference array name derived from this class name (arrays of an unloaded

   // class can't be referenced anymore).

   if (_array_name != NULL)  _array_name->decrement_refcount();

   if (_source_file_name != NULL) _source_file_name->decrement_refcount();

   if (_source_debug_extension != NULL) _source_debug_extension->decrement_refcount();

   // walk constant pool and decrement symbol reference counts

   _constants->unreference_symbols();

 }

 void instanceKlass::set_source_file_name(Symbol* n) {

   _source_file_name = n;

   if (_source_file_name != NULL) _source_file_name->increment_refcount();

 }

 void instanceKlass::set_source_debug_extension(Symbol* n) {

   _source_debug_extension = n;

   if (_source_debug_extension != NULL) _source_debug_extension->increment_refcount();

 }

 address instanceKlass::static_field_addr(int offset) {

   return (address)(offset + instanceMirrorKlass::offset_of_static_fields() + (intptr_t)java_mirror());

 }

 const char* instanceKlass::signature_name() const {

   const char* src = (const char*) (name()->as_C_string());

   const int src_length = (int)strlen(src);

   char* dest = NEW_RESOURCE_ARRAY(char, src_length + 3);

   int src_index = 0;

   int dest_index = 0;

   dest[dest_index++] = 'L';

   while (src_index < src_length) {

     dest[dest_index++] = src[src_index++];

   }

   dest[dest_index++] = ';';

   dest[dest_index] = '\0';

   return dest;

 }

 // different verisons of is_same_class_package

 bool instanceKlass::is_same_class_package(klassOop class2) {

   klassOop class1 = as_klassOop();

   oop classloader1 = instanceKlass::cast(class1)->class_loader();

   Symbol* classname1 = Klass::cast(class1)->name();

   if (Klass::cast(class2)->oop_is_objArray()) {

     class2 = objArrayKlass::cast(class2)->bottom_klass();

   }

   oop classloader2;

   if (Klass::cast(class2)->oop_is_instance()) {

     classloader2 = instanceKlass::cast(class2)->class_loader();

   } else {

     assert(Klass::cast(class2)->oop_is_typeArray(), "should be type array");

     classloader2 = NULL;

   }

   Symbol* classname2 = Klass::cast(class2)->name();

   return instanceKlass::is_same_class_package(classloader1, classname1,

                                               classloader2, classname2);

 }

 bool instanceKlass::is_same_class_package(oop classloader2, Symbol* classname2) {

   klassOop class1 = as_klassOop();

   oop classloader1 = instanceKlass::cast(class1)->class_loader();

   Symbol* classname1 = Klass::cast(class1)->name();

   return instanceKlass::is_same_class_package(classloader1, classname1,

                                               classloader2, classname2);

 }

 // return true if two classes are in the same package, classloader

 // and classname information is enough to determine a class's package

 bool instanceKlass::is_same_class_package(oop class_loader1, Symbol* class_name1,

                                           oop class_loader2, Symbol* class_name2) {

   if (class_loader1 != class_loader2) {

     return false;

   } else if (class_name1 == class_name2) {

     return true;                // skip painful bytewise comparison

   } else {

     ResourceMark rm;

     // The Symbol*'s are in UTF8 encoding. Since we only need to check explicitly

     // for ASCII characters ('/', 'L', '['), we can keep them in UTF8 encoding.

     // Otherwise, we just compare jbyte values between the strings.

     const jbyte *name1 = class_name1->base();

     const jbyte *name2 = class_name2->base();

     const jbyte *last_slash1 = UTF8::strrchr(name1, class_name1->utf8_length(), '/');

     const jbyte *last_slash2 = UTF8::strrchr(name2, class_name2->utf8_length(), '/');

     if ((last_slash1 == NULL) || (last_slash2 == NULL)) {

       // One of the two doesn't have a package.  Only return true

       // if the other one also doesn't have a package.

       return last_slash1 == last_slash2;

     } else {

       // Skip over '['s

       if (*name1 == '[') {

         do {

           name1++;

         } while (*name1 == '[');

         if (*name1 != 'L') {

           // Something is terribly wrong.  Shouldn't be here.

           return false;

         }

       }

       if (*name2 == '[') {

         do {

           name2++;

         } while (*name2 == '[');

         if (*name2 != 'L') {

           // Something is terribly wrong.  Shouldn't be here.

           return false;

         }

       }

       // Check that package part is identical

       int length1 = last_slash1 - name1;

       int length2 = last_slash2 - name2;

       return UTF8::equal(name1, length1, name2, length2);

     }

   }

 }

 // Returns true iff super_method can be overridden by a method in targetclassname

 // See JSL 3rd edition 8.4.6.1

 // Assumes name-signature match

 // "this" is instanceKlass of super_method which must exist

 // note that the instanceKlass of the method in the targetclassname has not always been created yet

 bool instanceKlass::is_override(methodHandle super_method, Handle targetclassloader, Symbol* targetclassname, TRAPS) {

    // Private methods can not be overridden

    if (super_method->is_private()) {

      return false;

    }

    // If super method is accessible, then override

    if ((super_method->is_protected()) ||

        (super_method->is_public())) {

      return true;

    }

    // Package-private methods are not inherited outside of package

    assert(super_method->is_package_private(), "must be package private");

    return(is_same_class_package(targetclassloader(), targetclassname));

 }

 /* defined for now in jvm.cpp, for historical reasons *--

 klassOop instanceKlass::compute_enclosing_class_impl(instanceKlassHandle self,

                                                      Symbol*& simple_name_result, TRAPS) {

   ...

 }

 */

 // tell if two classes have the same enclosing class (at package level)

 bool instanceKlass::is_same_package_member_impl(instanceKlassHandle class1,

                                                 klassOop class2_oop, TRAPS) {

   if (class2_oop == class1->as_klassOop())          return true;

   if (!Klass::cast(class2_oop)->oop_is_instance())  return false;

   instanceKlassHandle class2(THREAD, class2_oop);

   // must be in same package before we try anything else

   if (!class1->is_same_class_package(class2->class_loader(), class2->name()))

     return false;

   // As long as there is an outer1.getEnclosingClass,

   // shift the search outward.

   instanceKlassHandle outer1 = class1;

   for (;;) {

     // As we walk along, look for equalities between outer1 and class2.

     // Eventually, the walks will terminate as outer1 stops

     // at the top-level class around the original class.

     bool ignore_inner_is_member;

     klassOop next = outer1->compute_enclosing_class(&ignore_inner_is_member,

                                                     CHECK_false);

     if (next == NULL)  break;

     if (next == class2())  return true;

     outer1 = instanceKlassHandle(THREAD, next);

   }

   // Now do the same for class2.

   instanceKlassHandle outer2 = class2;

   for (;;) {

     bool ignore_inner_is_member;

     klassOop next = outer2->compute_enclosing_class(&ignore_inner_is_member,

                                                     CHECK_false);

     if (next == NULL)  break;

     // Might as well check the new outer against all available values.

     if (next == class1())  return true;

     if (next == outer1())  return true;

     outer2 = instanceKlassHandle(THREAD, next);

   }

   // If by this point we have not found an equality between the

   // two classes, we know they are in separate package members.

   return false;

 }

 jint instanceKlass::compute_modifier_flags(TRAPS) const {

   klassOop k = as_klassOop();

   jint access = access_flags().as_int();

   // But check if it happens to be member class.

   instanceKlassHandle ik(THREAD, k);

   InnerClassesIterator iter(ik);

   for (; !iter.done(); iter.next()) {

     int ioff = iter.inner_class_info_index();

     // Inner class attribute can be zero, skip it.

     // Strange but true:  JVM spec. allows null inner class refs.

     if (ioff == 0) continue;

     // only look at classes that are already loaded

     // since we are looking for the flags for our self.

     Symbol* inner_name = ik->constants()->klass_name_at(ioff);

     if ((ik->name() == inner_name)) {

       // This is really a member class.

       access = iter.inner_access_flags();

       break;

     }

   }

   // Remember to strip ACC_SUPER bit

   return (access & (~JVM_ACC_SUPER)) & JVM_ACC_WRITTEN_FLAGS;

 }

 jint instanceKlass::jvmti_class_status() const {

   jint result = 0;

   if (is_linked()) {

     result |= JVMTI_CLASS_STATUS_VERIFIED | JVMTI_CLASS_STATUS_PREPARED;

   }

   if (is_initialized()) {

     assert(is_linked(), "Class status is not consistent");

     result |= JVMTI_CLASS_STATUS_INITIALIZED;

   }

   if (is_in_error_state()) {

     result |= JVMTI_CLASS_STATUS_ERROR;

   }

   return result;

 }

 methodOop instanceKlass::method_at_itable(klassOop holder, int index, TRAPS) {

   itableOffsetEntry* ioe = (itableOffsetEntry*)start_of_itable();

   int method_table_offset_in_words = ioe->offset()/wordSize;

   int nof_interfaces = (method_table_offset_in_words - itable_offset_in_words())

                        / itableOffsetEntry::size();

   for (int cnt = 0 ; ; cnt ++, ioe ++) {

     // If the interface isn't implemented by the receiver class,

     // the VM should throw IncompatibleClassChangeError.

     if (cnt >= nof_interfaces) {

       THROW_0(vmSymbols::java_lang_IncompatibleClassChangeError());

     }

     klassOop ik = ioe->interface_klass();

     if (ik == holder) break;

   }

   itableMethodEntry* ime = ioe->first_method_entry(as_klassOop());

   methodOop m = ime[index].method();

   if (m == NULL) {

     THROW_0(vmSymbols::java_lang_AbstractMethodError());

   }

   return m;

 }

 // On-stack replacement stuff

 void instanceKlass::add_osr_nmethod(nmethod* n) {

   // only one compilation can be active

   NEEDS_CLEANUP

   // This is a short non-blocking critical region, so the no safepoint check is ok.

   OsrList_lock->lock_without_safepoint_check();

   assert(n->is_osr_method(), "wrong kind of nmethod");

   n->set_osr_link(osr_nmethods_head());

   set_osr_nmethods_head(n);

   // Raise the highest osr level if necessary

   if (TieredCompilation) {

     methodOop m = n->method();

     m->set_highest_osr_comp_level(MAX2(m->highest_osr_comp_level(), n->comp_level()));

   }

   // Remember to unlock again

   OsrList_lock->unlock();

   // Get rid of the osr methods for the same bci that have lower levels.

   if (TieredCompilation) {

     for (int l = CompLevel_limited_profile; l < n->comp_level(); l++) {

       nmethod *inv = lookup_osr_nmethod(n->method(), n->osr_entry_bci(), l, true);

       if (inv != NULL && inv->is_in_use()) {

         inv->make_not_entrant();

       }

     }

   }

 }

 void instanceKlass::remove_osr_nmethod(nmethod* n) {

   // This is a short non-blocking critical region, so the no safepoint check is ok.

   OsrList_lock->lock_without_safepoint_check();

   assert(n->is_osr_method(), "wrong kind of nmethod");

   nmethod* last = NULL;

   nmethod* cur  = osr_nmethods_head();

   int max_level = CompLevel_none;  // Find the max comp level excluding n

   methodOop m = n->method();

   // Search for match

   while(cur != NULL && cur != n) {

     if (TieredCompilation) {

       // Find max level before n

       max_level = MAX2(max_level, cur->comp_level());

     }

     last = cur;

     cur = cur->osr_link();

   }

   nmethod* next = NULL;

   if (cur == n) {

     next = cur->osr_link();

     if (last == NULL) {

       // Remove first element

       set_osr_nmethods_head(next);

     } else {

       last->set_osr_link(next);

     }

   }

   n->set_osr_link(NULL);

   if (TieredCompilation) {

     cur = next;

     while (cur != NULL) {

       // Find max level after n

       max_level = MAX2(max_level, cur->comp_level());

       cur = cur->osr_link();

     }

     m->set_highest_osr_comp_level(max_level);

   }

   // Remember to unlock again

   OsrList_lock->unlock();

 }

 nmethod* instanceKlass::lookup_osr_nmethod(const methodOop m, int bci, int comp_level, bool match_level) const {

   // This is a short non-blocking critical region, so the no safepoint check is ok.

   OsrList_lock->lock_without_safepoint_check();

   nmethod* osr = osr_nmethods_head();

   nmethod* best = NULL;

   while (osr != NULL) {

     assert(osr->is_osr_method(), "wrong kind of nmethod found in chain");

     // There can be a time when a c1 osr method exists but we are waiting

     // for a c2 version. When c2 completes its osr nmethod we will trash

     // the c1 version and only be able to find the c2 version. However

     // while we overflow in the c1 code at back branches we don't want to

     // try and switch to the same code as we are already running

     if (osr->method() == m &&

         (bci == InvocationEntryBci || osr->osr_entry_bci() == bci)) {

       if (match_level) {

         if (osr->comp_level() == comp_level) {

           // Found a match - return it.

           OsrList_lock->unlock();

           return osr;

         }

       } else {

         if (best == NULL || (osr->comp_level() > best->comp_level())) {

           if (osr->comp_level() == CompLevel_highest_tier) {

             // Found the best possible - return it.

             OsrList_lock->unlock();

             return osr;

           }

           best = osr;

         }

       }

     }

     osr = osr->osr_link();

   }

   OsrList_lock->unlock();

   if (best != NULL && best->comp_level() >= comp_level && match_level == false) {

     return best;

   }

   return NULL;

 }

 // -----------------------------------------------------------------------------------------------------

 #ifndef PRODUCT

 // Printing

 #define BULLET  " - "

 void FieldPrinter::do_field(fieldDescriptor* fd) {

   _st->print(BULLET);

    if (_obj == NULL) {

      fd->print_on(_st);

      _st->cr();

    } else {

      fd->print_on_for(_st, _obj);

      _st->cr();

    }

 }

 void instanceKlass::oop_print_on(oop obj, outputStream* st) {

   Klass::oop_print_on(obj, st);

   if (as_klassOop() == SystemDictionary::String_klass()) {

     typeArrayOop value  = java_lang_String::value(obj);

     juint        offset = java_lang_String::offset(obj);

     juint        length = java_lang_String::length(obj);

     if (value != NULL &&

         value->is_typeArray() &&

         offset          <= (juint) value->length() &&

         offset + length <= (juint) value->length()) {

       st->print(BULLET"string: ");

       Handle h_obj(obj);

       java_lang_String::print(h_obj, st);

       st->cr();

       if (!WizardMode)  return;  // that is enough

     }

   }

   st->print_cr(BULLET"---- fields (total size %d words):", oop_size(obj));

   FieldPrinter print_field(st, obj);

   do_nonstatic_fields(&print_field);

   if (as_klassOop() == SystemDictionary::Class_klass()) {

     st->print(BULLET"signature: ");

     java_lang_Class::print_signature(obj, st);

     st->cr();

     klassOop mirrored_klass = java_lang_Class::as_klassOop(obj);

     st->print(BULLET"fake entry for mirror: ");

     mirrored_klass->print_value_on(st);

     st->cr();

     st->print(BULLET"fake entry resolved_constructor: ");

     methodOop ctor = java_lang_Class::resolved_constructor(obj);

     ctor->print_value_on(st);

     klassOop array_klass = java_lang_Class::array_klass(obj);

     st->cr();

     st->print(BULLET"fake entry for array: ");

     array_klass->print_value_on(st);

     st->cr();

     st->print_cr(BULLET"fake entry for oop_size: %d", java_lang_Class::oop_size(obj));

     st->print_cr(BULLET"fake entry for static_oop_field_count: %d", java_lang_Class::static_oop_field_count(obj));

     klassOop real_klass = java_lang_Class::as_klassOop(obj);

     if (real_klass != NULL && real_klass->klass_part()->oop_is_instance()) {

       instanceKlass::cast(real_klass)->do_local_static_fields(&print_field);

     }

   } else if (as_klassOop() == SystemDictionary::MethodType_klass()) {

     st->print(BULLET"signature: ");

     java_lang_invoke_MethodType::print_signature(obj, st);

     st->cr();

   }

 }

 #endif //PRODUCT

 void instanceKlass::oop_print_value_on(oop obj, outputStream* st) {

   st->print("a ");

   name()->print_value_on(st);

   obj->print_address_on(st);

   if (as_klassOop() == SystemDictionary::String_klass()

       && java_lang_String::value(obj) != NULL) {

     ResourceMark rm;

     int len = java_lang_String::length(obj);

     int plen = (len < 24 ? len : 12);

     char* str = java_lang_String::as_utf8_string(obj, 0, plen);

     st->print(" = \"%s\"", str);

     if (len > plen)

       st->print("...[%d]", len);

   } else if (as_klassOop() == SystemDictionary::Class_klass()) {

     klassOop k = java_lang_Class::as_klassOop(obj);

     st->print(" = ");

     if (k != NULL) {

       k->print_value_on(st);

     } else {

       const char* tname = type2name(java_lang_Class::primitive_type(obj));

       st->print("%s", tname ? tname : "type?");

     }

   } else if (as_klassOop() == SystemDictionary::MethodType_klass()) {

     st->print(" = ");

     java_lang_invoke_MethodType::print_signature(obj, st);

   } else if (java_lang_boxing_object::is_instance(obj)) {

     st->print(" = ");

     java_lang_boxing_object::print(obj, st);

   }

 }

 const char* instanceKlass::internal_name() const {

   return external_name();

 }

 // Verification

 class VerifyFieldClosure: public OopClosure {

  protected:

   template <class T> void do_oop_work(T* p) {

     guarantee(Universe::heap()->is_in_closed_subset(p), "should be in heap");

     oop obj = oopDesc::load_decode_heap_oop(p);

     if (!obj->is_oop_or_null()) {

       tty->print_cr("Failed: " PTR_FORMAT " -> " PTR_FORMAT, p, (address)obj);

       Universe::print();

       guarantee(false, "boom");

     }

   }

  public:

   virtual void do_oop(oop* p)       { VerifyFieldClosure::do_oop_work(p); }

   virtual void do_oop(narrowOop* p) { VerifyFieldClosure::do_oop_work(p); }

 };

 void instanceKlass::oop_verify_on(oop obj, outputStream* st) {

   Klass::oop_verify_on(obj, st);

   VerifyFieldClosure blk;

   oop_oop_iterate(obj, &blk);

 }

 // JNIid class for jfieldIDs only

 // Note to reviewers:

 // These JNI functions are just moved over to column 1 and not changed

 // in the compressed oops workspace.

 JNIid::JNIid(klassOop holder, int offset, JNIid* next) {

   _holder = holder;

   _offset = offset;

   _next = next;

   debug_only(_is_static_field_id = false;)

 }

 JNIid* JNIid::find(int offset) {

   JNIid* current = this;

   while (current != NULL) {

     if (current->offset() == offset) return current;

     current = current->next();

   }

   return NULL;

 }

 void JNIid::oops_do(OopClosure* f) {

   for (JNIid* cur = this; cur != NULL; cur = cur->next()) {

     f->do_oop(cur->holder_addr());

   }

 }

 void JNIid::deallocate(JNIid* current) {

   while (current != NULL) {

     JNIid* next = current->next();

     delete current;

     current = next;

   }

 }

 void JNIid::verify(klassOop holder) {

   int first_field_offset  = instanceMirrorKlass::offset_of_static_fields();

   int end_field_offset;

   end_field_offset = first_field_offset + (instanceKlass::cast(holder)->static_field_size() * wordSize);

   JNIid* current = this;

   while (current != NULL) {

     guarantee(current->holder() == holder, "Invalid klass in JNIid");

 #ifdef ASSERT

     int o = current->offset();

     if (current->is_static_field_id()) {

       guarantee(o >= first_field_offset  && o < end_field_offset,  "Invalid static field offset in JNIid");

     }

 #endif

     current = current->next();

   }

 }

 #ifdef ASSERT

 void instanceKlass::set_init_state(ClassState state) {

   bool good_state = as_klassOop()->is_shared() ? (_init_state <= state)

                                                : (_init_state < state);

   assert(good_state || state == allocated, "illegal state transition");

   _init_state = (u1)state;

 }

 #endif

 // RedefineClasses() support for previous versions:

 // Add an information node that contains weak references to the

 // interesting parts of the previous version of the_class.

 // This is also where we clean out any unused weak references.

 // Note that while we delete nodes from the _previous_versions

 // array, we never delete the array itself until the klass is

 // unloaded. The has_been_redefined() query depends on that fact.

 //

 void instanceKlass::add_previous_version(instanceKlassHandle ikh,

        BitMap* emcp_methods, int emcp_method_count) {

   assert(Thread::current()->is_VM_thread(),

          "only VMThread can add previous versions");

   if (_previous_versions == NULL) {

     // This is the first previous version so make some space.

     // Start with 2 elements under the assumption that the class

     // won't be redefined much.

     _previous_versions =  new (ResourceObj::C_HEAP)

                             GrowableArray<PreviousVersionNode *>(2, true);

   }

   // RC_TRACE macro has an embedded ResourceMark

   RC_TRACE(0x00000100, ("adding previous version ref for %s @%d, EMCP_cnt=%d",

     ikh->external_name(), _previous_versions->length(), emcp_method_count));

   constantPoolHandle cp_h(ikh->constants());

   jobject cp_ref;

   if (cp_h->is_shared()) {

     // a shared ConstantPool requires a regular reference; a weak

     // reference would be collectible

     cp_ref = JNIHandles::make_global(cp_h);

   } else {

     cp_ref = JNIHandles::make_weak_global(cp_h);

   }

   PreviousVersionNode * pv_node = NULL;

   objArrayOop old_methods = ikh->methods();

   if (emcp_method_count == 0) {

     // non-shared ConstantPool gets a weak reference

     pv_node = new PreviousVersionNode(cp_ref, !cp_h->is_shared(), NULL);

     RC_TRACE(0x00000400,

       ("add: all methods are obsolete; flushing any EMCP weak refs"));

   } else {

     int local_count = 0;

     GrowableArray<jweak>* method_refs = new (ResourceObj::C_HEAP)

       GrowableArray<jweak>(emcp_method_count, true);

     for (int i = 0; i < old_methods->length(); i++) {

       if (emcp_methods->at(i)) {

         // this old method is EMCP so save a weak ref

         methodOop old_method = (methodOop) old_methods->obj_at(i);

         methodHandle old_method_h(old_method);

         jweak method_ref = JNIHandles::make_weak_global(old_method_h);

         method_refs->append(method_ref);

         if (++local_count >= emcp_method_count) {

           // no more EMCP methods so bail out now

           break;

         }

       }

     }

     // non-shared ConstantPool gets a weak reference

     pv_node = new PreviousVersionNode(cp_ref, !cp_h->is_shared(), method_refs);

   }

   _previous_versions->append(pv_node);

   // Using weak references allows the interesting parts of previous

   // classes to be GC'ed when they are no longer needed. Since the

   // caller is the VMThread and we are at a safepoint, this is a good

   // time to clear out unused weak references.

   RC_TRACE(0x00000400, ("add: previous version length=%d",

     _previous_versions->length()));

   // skip the last entry since we just added it

   for (int i = _previous_versions->length() - 2; i >= 0; i--) {

     // check the previous versions array for a GC'ed weak refs

     pv_node = _previous_versions->at(i);

     cp_ref = pv_node->prev_constant_pool();

     assert(cp_ref != NULL, "cp ref was unexpectedly cleared");

     if (cp_ref == NULL) {

       delete pv_node;

       _previous_versions->remove_at(i);

       // Since we are traversing the array backwards, we don't have to

       // do anything special with the index.

       continue;  // robustness

     }

     constantPoolOop cp = (constantPoolOop)JNIHandles::resolve(cp_ref);

     if (cp == NULL) {

       // this entry has been GC'ed so remove it

       delete pv_node;

       _previous_versions->remove_at(i);

       // Since we are traversing the array backwards, we don't have to

       // do anything special with the index.

       continue;

     } else {

       RC_TRACE(0x00000400, ("add: previous version @%d is alive", i));

     }

     GrowableArray<jweak>* method_refs = pv_node->prev_EMCP_methods();

     if (method_refs != NULL) {

       RC_TRACE(0x00000400, ("add: previous methods length=%d",

         method_refs->length()));

       for (int j = method_refs->length() - 1; j >= 0; j--) {

         jweak method_ref = method_refs->at(j);

         assert(method_ref != NULL, "weak method ref was unexpectedly cleared");

         if (method_ref == NULL) {

           method_refs->remove_at(j);

           // Since we are traversing the array backwards, we don't have to

           // do anything special with the index.

           continue;  // robustness

         }

         methodOop method = (methodOop)JNIHandles::resolve(method_ref);

         if (method == NULL || emcp_method_count == 0) {

           // This method entry has been GC'ed or the current

           // RedefineClasses() call has made all methods obsolete

           // so remove it.

           JNIHandles::destroy_weak_global(method_ref);

           method_refs->remove_at(j);

         } else {

           // RC_TRACE macro has an embedded ResourceMark

           RC_TRACE(0x00000400,

             ("add: %s(%s): previous method @%d in version @%d is alive",

             method->name()->as_C_string(), method->signature()->as_C_string(),

             j, i));

         }

       }

     }

   }

   int obsolete_method_count = old_methods->length() - emcp_method_count;

   if (emcp_method_count != 0 && obsolete_method_count != 0 &&

       _previous_versions->length() > 1) {