src/share/vm/oops/instanceKlass.cpp

Fri, 04 Mar 2011 14:40:46 -0500

author
kamg
date
Fri, 04 Mar 2011 14:40:46 -0500
changeset 2616
dbad0519a1c4
parent 2534
e5383553fd4e
child 2639
8033953d67ff
permissions
-rw-r--r--

6845426: non-static <clinit> method with no args is called during the class initialization process
Summary: Only call <clinit> with ACC_STATIC for classfiles with version > 50
Reviewed-by: acorn, dholmes, coleenp

     1 /*
     2  * Copyright (c) 1997, 2011, Oracle and/or its affiliates. All rights reserved.
     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
     4  *
     5  * This code is free software; you can redistribute it and/or modify it
     6  * under the terms of the GNU General Public License version 2 only, as
     7  * published by the Free Software Foundation.
     8  *
     9  * This code is distributed in the hope that it will be useful, but WITHOUT
    10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
    11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
    12  * version 2 for more details (a copy is included in the LICENSE file that
    13  * accompanied this code).
    14  *
    15  * You should have received a copy of the GNU General Public License version
    16  * 2 along with this work; if not, write to the Free Software Foundation,
    17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
    18  *
    19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
    20  * or visit www.oracle.com if you need additional information or have any
    21  * questions.
    22  *
    23  */
    25 #include "precompiled.hpp"
    26 #include "classfile/javaClasses.hpp"
    27 #include "classfile/systemDictionary.hpp"
    28 #include "classfile/verifier.hpp"
    29 #include "classfile/vmSymbols.hpp"
    30 #include "compiler/compileBroker.hpp"
    31 #include "gc_implementation/shared/markSweep.inline.hpp"
    32 #include "gc_interface/collectedHeap.inline.hpp"
    33 #include "interpreter/oopMapCache.hpp"
    34 #include "interpreter/rewriter.hpp"
    35 #include "jvmtifiles/jvmti.h"
    36 #include "memory/genOopClosures.inline.hpp"
    37 #include "memory/oopFactory.hpp"
    38 #include "memory/permGen.hpp"
    39 #include "oops/instanceKlass.hpp"
    40 #include "oops/instanceOop.hpp"
    41 #include "oops/methodOop.hpp"
    42 #include "oops/objArrayKlassKlass.hpp"
    43 #include "oops/oop.inline.hpp"
    44 #include "oops/symbol.hpp"
    45 #include "prims/jvmtiExport.hpp"
    46 #include "prims/jvmtiRedefineClassesTrace.hpp"
    47 #include "runtime/fieldDescriptor.hpp"
    48 #include "runtime/handles.inline.hpp"
    49 #include "runtime/javaCalls.hpp"
    50 #include "runtime/mutexLocker.hpp"
    51 #include "services/threadService.hpp"
    52 #include "utilities/dtrace.hpp"
    53 #ifdef TARGET_OS_FAMILY_linux
    54 # include "thread_linux.inline.hpp"
    55 #endif
    56 #ifdef TARGET_OS_FAMILY_solaris
    57 # include "thread_solaris.inline.hpp"
    58 #endif
    59 #ifdef TARGET_OS_FAMILY_windows
    60 # include "thread_windows.inline.hpp"
    61 #endif
    62 #ifndef SERIALGC
    63 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
    64 #include "gc_implementation/g1/g1OopClosures.inline.hpp"
    65 #include "gc_implementation/g1/g1RemSet.inline.hpp"
    66 #include "gc_implementation/g1/heapRegionSeq.inline.hpp"
    67 #include "gc_implementation/parNew/parOopClosures.inline.hpp"
    68 #include "gc_implementation/parallelScavenge/psPromotionManager.inline.hpp"
    69 #include "gc_implementation/parallelScavenge/psScavenge.inline.hpp"
    70 #include "oops/oop.pcgc.inline.hpp"
    71 #endif
    72 #ifdef COMPILER1
    73 #include "c1/c1_Compiler.hpp"
    74 #endif
    76 #ifdef DTRACE_ENABLED
    78 HS_DTRACE_PROBE_DECL4(hotspot, class__initialization__required,
    79   char*, intptr_t, oop, intptr_t);
    80 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__recursive,
    81   char*, intptr_t, oop, intptr_t, int);
    82 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__concurrent,
    83   char*, intptr_t, oop, intptr_t, int);
    84 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__erroneous,
    85   char*, intptr_t, oop, intptr_t, int);
    86 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__super__failed,
    87   char*, intptr_t, oop, intptr_t, int);
    88 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__clinit,
    89   char*, intptr_t, oop, intptr_t, int);
    90 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__error,
    91   char*, intptr_t, oop, intptr_t, int);
    92 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__end,
    93   char*, intptr_t, oop, intptr_t, int);
    95 #define DTRACE_CLASSINIT_PROBE(type, clss, thread_type)          \
    96   {                                                              \
    97     char* data = NULL;                                           \
    98     int len = 0;                                                 \
    99     Symbol* name = (clss)->name();                               \
   100     if (name != NULL) {                                          \
   101       data = (char*)name->bytes();                               \
   102       len = name->utf8_length();                                 \
   103     }                                                            \
   104     HS_DTRACE_PROBE4(hotspot, class__initialization__##type,     \
   105       data, len, (clss)->class_loader(), thread_type);           \
   106   }
   108 #define DTRACE_CLASSINIT_PROBE_WAIT(type, clss, thread_type, wait) \
   109   {                                                              \
   110     char* data = NULL;                                           \
   111     int len = 0;                                                 \
   112     Symbol* name = (clss)->name();                               \
   113     if (name != NULL) {                                          \
   114       data = (char*)name->bytes();                               \
   115       len = name->utf8_length();                                 \
   116     }                                                            \
   117     HS_DTRACE_PROBE5(hotspot, class__initialization__##type,     \
   118       data, len, (clss)->class_loader(), thread_type, wait);     \
   119   }
   121 #else //  ndef DTRACE_ENABLED
   123 #define DTRACE_CLASSINIT_PROBE(type, clss, thread_type)
   124 #define DTRACE_CLASSINIT_PROBE_WAIT(type, clss, thread_type, wait)
   126 #endif //  ndef DTRACE_ENABLED
   128 bool instanceKlass::should_be_initialized() const {
   129   return !is_initialized();
   130 }
   132 klassVtable* instanceKlass::vtable() const {
   133   return new klassVtable(as_klassOop(), start_of_vtable(), vtable_length() / vtableEntry::size());
   134 }
   136 klassItable* instanceKlass::itable() const {
   137   return new klassItable(as_klassOop());
   138 }
   140 void instanceKlass::eager_initialize(Thread *thread) {
   141   if (!EagerInitialization) return;
   143   if (this->is_not_initialized()) {
   144     // abort if the the class has a class initializer
   145     if (this->class_initializer() != NULL) return;
   147     // abort if it is java.lang.Object (initialization is handled in genesis)
   148     klassOop super = this->super();
   149     if (super == NULL) return;
   151     // abort if the super class should be initialized
   152     if (!instanceKlass::cast(super)->is_initialized()) return;
   154     // call body to expose the this pointer
   155     instanceKlassHandle this_oop(thread, this->as_klassOop());
   156     eager_initialize_impl(this_oop);
   157   }
   158 }
   161 void instanceKlass::eager_initialize_impl(instanceKlassHandle this_oop) {
   162   EXCEPTION_MARK;
   163   ObjectLocker ol(this_oop, THREAD);
   165   // abort if someone beat us to the initialization
   166   if (!this_oop->is_not_initialized()) return;  // note: not equivalent to is_initialized()
   168   ClassState old_state = this_oop->_init_state;
   169   link_class_impl(this_oop, true, THREAD);
   170   if (HAS_PENDING_EXCEPTION) {
   171     CLEAR_PENDING_EXCEPTION;
   172     // Abort if linking the class throws an exception.
   174     // Use a test to avoid redundantly resetting the state if there's
   175     // no change.  Set_init_state() asserts that state changes make
   176     // progress, whereas here we might just be spinning in place.
   177     if( old_state != this_oop->_init_state )
   178       this_oop->set_init_state (old_state);
   179   } else {
   180     // linking successfull, mark class as initialized
   181     this_oop->set_init_state (fully_initialized);
   182     // trace
   183     if (TraceClassInitialization) {
   184       ResourceMark rm(THREAD);
   185       tty->print_cr("[Initialized %s without side effects]", this_oop->external_name());
   186     }
   187   }
   188 }
   191 // See "The Virtual Machine Specification" section 2.16.5 for a detailed explanation of the class initialization
   192 // process. The step comments refers to the procedure described in that section.
   193 // Note: implementation moved to static method to expose the this pointer.
   194 void instanceKlass::initialize(TRAPS) {
   195   if (this->should_be_initialized()) {
   196     HandleMark hm(THREAD);
   197     instanceKlassHandle this_oop(THREAD, this->as_klassOop());
   198     initialize_impl(this_oop, CHECK);
   199     // Note: at this point the class may be initialized
   200     //       OR it may be in the state of being initialized
   201     //       in case of recursive initialization!
   202   } else {
   203     assert(is_initialized(), "sanity check");
   204   }
   205 }
   208 bool instanceKlass::verify_code(
   209     instanceKlassHandle this_oop, bool throw_verifyerror, TRAPS) {
   210   // 1) Verify the bytecodes
   211   Verifier::Mode mode =
   212     throw_verifyerror ? Verifier::ThrowException : Verifier::NoException;
   213   return Verifier::verify(this_oop, mode, this_oop->should_verify_class(), CHECK_false);
   214 }
   217 // Used exclusively by the shared spaces dump mechanism to prevent
   218 // classes mapped into the shared regions in new VMs from appearing linked.
   220 void instanceKlass::unlink_class() {
   221   assert(is_linked(), "must be linked");
   222   _init_state = loaded;
   223 }
   225 void instanceKlass::link_class(TRAPS) {
   226   assert(is_loaded(), "must be loaded");
   227   if (!is_linked()) {
   228     instanceKlassHandle this_oop(THREAD, this->as_klassOop());
   229     link_class_impl(this_oop, true, CHECK);
   230   }
   231 }
   233 // Called to verify that a class can link during initialization, without
   234 // throwing a VerifyError.
   235 bool instanceKlass::link_class_or_fail(TRAPS) {
   236   assert(is_loaded(), "must be loaded");
   237   if (!is_linked()) {
   238     instanceKlassHandle this_oop(THREAD, this->as_klassOop());
   239     link_class_impl(this_oop, false, CHECK_false);
   240   }
   241   return is_linked();
   242 }
   244 bool instanceKlass::link_class_impl(
   245     instanceKlassHandle this_oop, bool throw_verifyerror, TRAPS) {
   246   // check for error state
   247   if (this_oop->is_in_error_state()) {
   248     ResourceMark rm(THREAD);
   249     THROW_MSG_(vmSymbols::java_lang_NoClassDefFoundError(),
   250                this_oop->external_name(), false);
   251   }
   252   // return if already verified
   253   if (this_oop->is_linked()) {
   254     return true;
   255   }
   257   // Timing
   258   // timer handles recursion
   259   assert(THREAD->is_Java_thread(), "non-JavaThread in link_class_impl");
   260   JavaThread* jt = (JavaThread*)THREAD;
   262   // link super class before linking this class
   263   instanceKlassHandle super(THREAD, this_oop->super());
   264   if (super.not_null()) {
   265     if (super->is_interface()) {  // check if super class is an interface
   266       ResourceMark rm(THREAD);
   267       Exceptions::fthrow(
   268         THREAD_AND_LOCATION,
   269         vmSymbols::java_lang_IncompatibleClassChangeError(),
   270         "class %s has interface %s as super class",
   271         this_oop->external_name(),
   272         super->external_name()
   273       );
   274       return false;
   275     }
   277     link_class_impl(super, throw_verifyerror, CHECK_false);
   278   }
   280   // link all interfaces implemented by this class before linking this class
   281   objArrayHandle interfaces (THREAD, this_oop->local_interfaces());
   282   int num_interfaces = interfaces->length();
   283   for (int index = 0; index < num_interfaces; index++) {
   284     HandleMark hm(THREAD);
   285     instanceKlassHandle ih(THREAD, klassOop(interfaces->obj_at(index)));
   286     link_class_impl(ih, throw_verifyerror, CHECK_false);
   287   }
   289   // in case the class is linked in the process of linking its superclasses
   290   if (this_oop->is_linked()) {
   291     return true;
   292   }
   294   // trace only the link time for this klass that includes
   295   // the verification time
   296   PerfClassTraceTime vmtimer(ClassLoader::perf_class_link_time(),
   297                              ClassLoader::perf_class_link_selftime(),
   298                              ClassLoader::perf_classes_linked(),
   299                              jt->get_thread_stat()->perf_recursion_counts_addr(),
   300                              jt->get_thread_stat()->perf_timers_addr(),
   301                              PerfClassTraceTime::CLASS_LINK);
   303   // verification & rewriting
   304   {
   305     ObjectLocker ol(this_oop, THREAD);
   306     // rewritten will have been set if loader constraint error found
   307     // on an earlier link attempt
   308     // don't verify or rewrite if already rewritten
   309     if (!this_oop->is_linked()) {
   310       if (!this_oop->is_rewritten()) {
   311         {
   312           // Timer includes any side effects of class verification (resolution,
   313           // etc), but not recursive entry into verify_code().
   314           PerfClassTraceTime timer(ClassLoader::perf_class_verify_time(),
   315                                    ClassLoader::perf_class_verify_selftime(),
   316                                    ClassLoader::perf_classes_verified(),
   317                                    jt->get_thread_stat()->perf_recursion_counts_addr(),
   318                                    jt->get_thread_stat()->perf_timers_addr(),
   319                                    PerfClassTraceTime::CLASS_VERIFY);
   320           bool verify_ok = verify_code(this_oop, throw_verifyerror, THREAD);
   321           if (!verify_ok) {
   322             return false;
   323           }
   324         }
   326         // Just in case a side-effect of verify linked this class already
   327         // (which can sometimes happen since the verifier loads classes
   328         // using custom class loaders, which are free to initialize things)
   329         if (this_oop->is_linked()) {
   330           return true;
   331         }
   333         // also sets rewritten
   334         this_oop->rewrite_class(CHECK_false);
   335       }
   337       // Initialize the vtable and interface table after
   338       // methods have been rewritten since rewrite may
   339       // fabricate new methodOops.
   340       // also does loader constraint checking
   341       if (!this_oop()->is_shared()) {
   342         ResourceMark rm(THREAD);
   343         this_oop->vtable()->initialize_vtable(true, CHECK_false);
   344         this_oop->itable()->initialize_itable(true, CHECK_false);
   345       }
   346 #ifdef ASSERT
   347       else {
   348         ResourceMark rm(THREAD);
   349         this_oop->vtable()->verify(tty, true);
   350         // In case itable verification is ever added.
   351         // this_oop->itable()->verify(tty, true);
   352       }
   353 #endif
   354       this_oop->set_init_state(linked);
   355       if (JvmtiExport::should_post_class_prepare()) {
   356         Thread *thread = THREAD;
   357         assert(thread->is_Java_thread(), "thread->is_Java_thread()");
   358         JvmtiExport::post_class_prepare((JavaThread *) thread, this_oop());
   359       }
   360     }
   361   }
   362   return true;
   363 }
   366 // Rewrite the byte codes of all of the methods of a class.
   367 // Three cases:
   368 //    During the link of a newly loaded class.
   369 //    During the preloading of classes to be written to the shared spaces.
   370 //      - Rewrite the methods and update the method entry points.
   371 //
   372 //    During the link of a class in the shared spaces.
   373 //      - The methods were already rewritten, update the metho entry points.
   374 //
   375 // The rewriter must be called exactly once. Rewriting must happen after
   376 // verification but before the first method of the class is executed.
   378 void instanceKlass::rewrite_class(TRAPS) {
   379   assert(is_loaded(), "must be loaded");
   380   instanceKlassHandle this_oop(THREAD, this->as_klassOop());
   381   if (this_oop->is_rewritten()) {
   382     assert(this_oop()->is_shared(), "rewriting an unshared class?");
   383     return;
   384   }
   385   Rewriter::rewrite(this_oop, CHECK); // No exception can happen here
   386   this_oop->set_rewritten();
   387 }
   390 void instanceKlass::initialize_impl(instanceKlassHandle this_oop, TRAPS) {
   391   // Make sure klass is linked (verified) before initialization
   392   // A class could already be verified, since it has been reflected upon.
   393   this_oop->link_class(CHECK);
   395   DTRACE_CLASSINIT_PROBE(required, instanceKlass::cast(this_oop()), -1);
   397   bool wait = false;
   399   // refer to the JVM book page 47 for description of steps
   400   // Step 1
   401   { ObjectLocker ol(this_oop, THREAD);
   403     Thread *self = THREAD; // it's passed the current thread
   405     // Step 2
   406     // If we were to use wait() instead of waitInterruptibly() then
   407     // we might end up throwing IE from link/symbol resolution sites
   408     // that aren't expected to throw.  This would wreak havoc.  See 6320309.
   409     while(this_oop->is_being_initialized() && !this_oop->is_reentrant_initialization(self)) {
   410         wait = true;
   411       ol.waitUninterruptibly(CHECK);
   412     }
   414     // Step 3
   415     if (this_oop->is_being_initialized() && this_oop->is_reentrant_initialization(self)) {
   416       DTRACE_CLASSINIT_PROBE_WAIT(recursive, instanceKlass::cast(this_oop()), -1,wait);
   417       return;
   418     }
   420     // Step 4
   421     if (this_oop->is_initialized()) {
   422       DTRACE_CLASSINIT_PROBE_WAIT(concurrent, instanceKlass::cast(this_oop()), -1,wait);
   423       return;
   424     }
   426     // Step 5
   427     if (this_oop->is_in_error_state()) {
   428       DTRACE_CLASSINIT_PROBE_WAIT(erroneous, instanceKlass::cast(this_oop()), -1,wait);
   429       ResourceMark rm(THREAD);
   430       const char* desc = "Could not initialize class ";
   431       const char* className = this_oop->external_name();
   432       size_t msglen = strlen(desc) + strlen(className) + 1;
   433       char* message = NEW_RESOURCE_ARRAY(char, msglen);
   434       if (NULL == message) {
   435         // Out of memory: can't create detailed error message
   436         THROW_MSG(vmSymbols::java_lang_NoClassDefFoundError(), className);
   437       } else {
   438         jio_snprintf(message, msglen, "%s%s", desc, className);
   439         THROW_MSG(vmSymbols::java_lang_NoClassDefFoundError(), message);
   440       }
   441     }
   443     // Step 6
   444     this_oop->set_init_state(being_initialized);
   445     this_oop->set_init_thread(self);
   446   }
   448   // Step 7
   449   klassOop super_klass = this_oop->super();
   450   if (super_klass != NULL && !this_oop->is_interface() && Klass::cast(super_klass)->should_be_initialized()) {
   451     Klass::cast(super_klass)->initialize(THREAD);
   453     if (HAS_PENDING_EXCEPTION) {
   454       Handle e(THREAD, PENDING_EXCEPTION);
   455       CLEAR_PENDING_EXCEPTION;
   456       {
   457         EXCEPTION_MARK;
   458         this_oop->set_initialization_state_and_notify(initialization_error, THREAD); // Locks object, set state, and notify all waiting threads
   459         CLEAR_PENDING_EXCEPTION;   // ignore any exception thrown, superclass initialization error is thrown below
   460       }
   461       DTRACE_CLASSINIT_PROBE_WAIT(super__failed, instanceKlass::cast(this_oop()), -1,wait);
   462       THROW_OOP(e());
   463     }
   464   }
   466   // Step 8
   467   {
   468     assert(THREAD->is_Java_thread(), "non-JavaThread in initialize_impl");
   469     JavaThread* jt = (JavaThread*)THREAD;
   470     DTRACE_CLASSINIT_PROBE_WAIT(clinit, instanceKlass::cast(this_oop()), -1,wait);
   471     // Timer includes any side effects of class initialization (resolution,
   472     // etc), but not recursive entry into call_class_initializer().
   473     PerfClassTraceTime timer(ClassLoader::perf_class_init_time(),
   474                              ClassLoader::perf_class_init_selftime(),
   475                              ClassLoader::perf_classes_inited(),
   476                              jt->get_thread_stat()->perf_recursion_counts_addr(),
   477                              jt->get_thread_stat()->perf_timers_addr(),
   478                              PerfClassTraceTime::CLASS_CLINIT);
   479     this_oop->call_class_initializer(THREAD);
   480   }
   482   // Step 9
   483   if (!HAS_PENDING_EXCEPTION) {
   484     this_oop->set_initialization_state_and_notify(fully_initialized, CHECK);
   485     { ResourceMark rm(THREAD);
   486       debug_only(this_oop->vtable()->verify(tty, true);)
   487     }
   488   }
   489   else {
   490     // Step 10 and 11
   491     Handle e(THREAD, PENDING_EXCEPTION);
   492     CLEAR_PENDING_EXCEPTION;
   493     {
   494       EXCEPTION_MARK;
   495       this_oop->set_initialization_state_and_notify(initialization_error, THREAD);
   496       CLEAR_PENDING_EXCEPTION;   // ignore any exception thrown, class initialization error is thrown below
   497     }
   498     DTRACE_CLASSINIT_PROBE_WAIT(error, instanceKlass::cast(this_oop()), -1,wait);
   499     if (e->is_a(SystemDictionary::Error_klass())) {
   500       THROW_OOP(e());
   501     } else {
   502       JavaCallArguments args(e);
   503       THROW_ARG(vmSymbols::java_lang_ExceptionInInitializerError(),
   504                 vmSymbols::throwable_void_signature(),
   505                 &args);
   506     }
   507   }
   508   DTRACE_CLASSINIT_PROBE_WAIT(end, instanceKlass::cast(this_oop()), -1,wait);
   509 }
   512 // Note: implementation moved to static method to expose the this pointer.
   513 void instanceKlass::set_initialization_state_and_notify(ClassState state, TRAPS) {
   514   instanceKlassHandle kh(THREAD, this->as_klassOop());
   515   set_initialization_state_and_notify_impl(kh, state, CHECK);
   516 }
   518 void instanceKlass::set_initialization_state_and_notify_impl(instanceKlassHandle this_oop, ClassState state, TRAPS) {
   519   ObjectLocker ol(this_oop, THREAD);
   520   this_oop->set_init_state(state);
   521   ol.notify_all(CHECK);
   522 }
   524 void instanceKlass::add_implementor(klassOop k) {
   525   assert(Compile_lock->owned_by_self(), "");
   526   // Filter out my subinterfaces.
   527   // (Note: Interfaces are never on the subklass list.)
   528   if (instanceKlass::cast(k)->is_interface()) return;
   530   // Filter out subclasses whose supers already implement me.
   531   // (Note: CHA must walk subclasses of direct implementors
   532   // in order to locate indirect implementors.)
   533   klassOop sk = instanceKlass::cast(k)->super();
   534   if (sk != NULL && instanceKlass::cast(sk)->implements_interface(as_klassOop()))
   535     // We only need to check one immediate superclass, since the
   536     // implements_interface query looks at transitive_interfaces.
   537     // Any supers of the super have the same (or fewer) transitive_interfaces.
   538     return;
   540   // Update number of implementors
   541   int i = _nof_implementors++;
   543   // Record this implementor, if there are not too many already
   544   if (i < implementors_limit) {
   545     assert(_implementors[i] == NULL, "should be exactly one implementor");
   546     oop_store_without_check((oop*)&_implementors[i], k);
   547   } else if (i == implementors_limit) {
   548     // clear out the list on first overflow
   549     for (int i2 = 0; i2 < implementors_limit; i2++)
   550       oop_store_without_check((oop*)&_implementors[i2], NULL);
   551   }
   553   // The implementor also implements the transitive_interfaces
   554   for (int index = 0; index < local_interfaces()->length(); index++) {
   555     instanceKlass::cast(klassOop(local_interfaces()->obj_at(index)))->add_implementor(k);
   556   }
   557 }
   559 void instanceKlass::init_implementor() {
   560   for (int i = 0; i < implementors_limit; i++)
   561     oop_store_without_check((oop*)&_implementors[i], NULL);
   562   _nof_implementors = 0;
   563 }
   566 void instanceKlass::process_interfaces(Thread *thread) {
   567   // link this class into the implementors list of every interface it implements
   568   KlassHandle this_as_oop (thread, this->as_klassOop());
   569   for (int i = local_interfaces()->length() - 1; i >= 0; i--) {
   570     assert(local_interfaces()->obj_at(i)->is_klass(), "must be a klass");
   571     instanceKlass* interf = instanceKlass::cast(klassOop(local_interfaces()->obj_at(i)));
   572     assert(interf->is_interface(), "expected interface");
   573     interf->add_implementor(this_as_oop());
   574   }
   575 }
   577 bool instanceKlass::can_be_primary_super_slow() const {
   578   if (is_interface())
   579     return false;
   580   else
   581     return Klass::can_be_primary_super_slow();
   582 }
   584 objArrayOop instanceKlass::compute_secondary_supers(int num_extra_slots, TRAPS) {
   585   // The secondaries are the implemented interfaces.
   586   instanceKlass* ik = instanceKlass::cast(as_klassOop());
   587   objArrayHandle interfaces (THREAD, ik->transitive_interfaces());
   588   int num_secondaries = num_extra_slots + interfaces->length();
   589   if (num_secondaries == 0) {
   590     return Universe::the_empty_system_obj_array();
   591   } else if (num_extra_slots == 0) {
   592     return interfaces();
   593   } else {
   594     // a mix of both
   595     objArrayOop secondaries = oopFactory::new_system_objArray(num_secondaries, CHECK_NULL);
   596     for (int i = 0; i < interfaces->length(); i++) {
   597       secondaries->obj_at_put(num_extra_slots+i, interfaces->obj_at(i));
   598     }
   599     return secondaries;
   600   }
   601 }
   603 bool instanceKlass::compute_is_subtype_of(klassOop k) {
   604   if (Klass::cast(k)->is_interface()) {
   605     return implements_interface(k);
   606   } else {
   607     return Klass::compute_is_subtype_of(k);
   608   }
   609 }
   611 bool instanceKlass::implements_interface(klassOop k) const {
   612   if (as_klassOop() == k) return true;
   613   assert(Klass::cast(k)->is_interface(), "should be an interface class");
   614   for (int i = 0; i < transitive_interfaces()->length(); i++) {
   615     if (transitive_interfaces()->obj_at(i) == k) {
   616       return true;
   617     }
   618   }
   619   return false;
   620 }
   622 objArrayOop instanceKlass::allocate_objArray(int n, int length, TRAPS) {
   623   if (length < 0) THROW_0(vmSymbols::java_lang_NegativeArraySizeException());
   624   if (length > arrayOopDesc::max_array_length(T_OBJECT)) {
   625     report_java_out_of_memory("Requested array size exceeds VM limit");
   626     THROW_OOP_0(Universe::out_of_memory_error_array_size());
   627   }
   628   int size = objArrayOopDesc::object_size(length);
   629   klassOop ak = array_klass(n, CHECK_NULL);
   630   KlassHandle h_ak (THREAD, ak);
   631   objArrayOop o =
   632     (objArrayOop)CollectedHeap::array_allocate(h_ak, size, length, CHECK_NULL);
   633   return o;
   634 }
   636 instanceOop instanceKlass::register_finalizer(instanceOop i, TRAPS) {
   637   if (TraceFinalizerRegistration) {
   638     tty->print("Registered ");
   639     i->print_value_on(tty);
   640     tty->print_cr(" (" INTPTR_FORMAT ") as finalizable", (address)i);
   641   }
   642   instanceHandle h_i(THREAD, i);
   643   // Pass the handle as argument, JavaCalls::call expects oop as jobjects
   644   JavaValue result(T_VOID);
   645   JavaCallArguments args(h_i);
   646   methodHandle mh (THREAD, Universe::finalizer_register_method());
   647   JavaCalls::call(&result, mh, &args, CHECK_NULL);
   648   return h_i();
   649 }
   651 instanceOop instanceKlass::allocate_instance(TRAPS) {
   652   bool has_finalizer_flag = has_finalizer(); // Query before possible GC
   653   int size = size_helper();  // Query before forming handle.
   655   KlassHandle h_k(THREAD, as_klassOop());
   657   instanceOop i;
   659   i = (instanceOop)CollectedHeap::obj_allocate(h_k, size, CHECK_NULL);
   660   if (has_finalizer_flag && !RegisterFinalizersAtInit) {
   661     i = register_finalizer(i, CHECK_NULL);
   662   }
   663   return i;
   664 }
   666 instanceOop instanceKlass::allocate_permanent_instance(TRAPS) {
   667   // Finalizer registration occurs in the Object.<init> constructor
   668   // and constructors normally aren't run when allocating perm
   669   // instances so simply disallow finalizable perm objects.  This can
   670   // be relaxed if a need for it is found.
   671   assert(!has_finalizer(), "perm objects not allowed to have finalizers");
   672   int size = size_helper();  // Query before forming handle.
   673   KlassHandle h_k(THREAD, as_klassOop());
   674   instanceOop i = (instanceOop)
   675     CollectedHeap::permanent_obj_allocate(h_k, size, CHECK_NULL);
   676   return i;
   677 }
   679 void instanceKlass::check_valid_for_instantiation(bool throwError, TRAPS) {
   680   if (is_interface() || is_abstract()) {
   681     ResourceMark rm(THREAD);
   682     THROW_MSG(throwError ? vmSymbols::java_lang_InstantiationError()
   683               : vmSymbols::java_lang_InstantiationException(), external_name());
   684   }
   685   if (as_klassOop() == SystemDictionary::Class_klass()) {
   686     ResourceMark rm(THREAD);
   687     THROW_MSG(throwError ? vmSymbols::java_lang_IllegalAccessError()
   688               : vmSymbols::java_lang_IllegalAccessException(), external_name());
   689   }
   690 }
   692 klassOop instanceKlass::array_klass_impl(bool or_null, int n, TRAPS) {
   693   instanceKlassHandle this_oop(THREAD, as_klassOop());
   694   return array_klass_impl(this_oop, or_null, n, THREAD);
   695 }
   697 klassOop instanceKlass::array_klass_impl(instanceKlassHandle this_oop, bool or_null, int n, TRAPS) {
   698   if (this_oop->array_klasses() == NULL) {
   699     if (or_null) return NULL;
   701     ResourceMark rm;
   702     JavaThread *jt = (JavaThread *)THREAD;
   703     {
   704       // Atomic creation of array_klasses
   705       MutexLocker mc(Compile_lock, THREAD);   // for vtables
   706       MutexLocker ma(MultiArray_lock, THREAD);
   708       // Check if update has already taken place
   709       if (this_oop->array_klasses() == NULL) {
   710         objArrayKlassKlass* oakk =
   711           (objArrayKlassKlass*)Universe::objArrayKlassKlassObj()->klass_part();
   713         klassOop  k = oakk->allocate_objArray_klass(1, this_oop, CHECK_NULL);
   714         this_oop->set_array_klasses(k);
   715       }
   716     }
   717   }
   718   // _this will always be set at this point
   719   objArrayKlass* oak = (objArrayKlass*)this_oop->array_klasses()->klass_part();
   720   if (or_null) {
   721     return oak->array_klass_or_null(n);
   722   }
   723   return oak->array_klass(n, CHECK_NULL);
   724 }
   726 klassOop instanceKlass::array_klass_impl(bool or_null, TRAPS) {
   727   return array_klass_impl(or_null, 1, THREAD);
   728 }
   730 void instanceKlass::call_class_initializer(TRAPS) {
   731   instanceKlassHandle ik (THREAD, as_klassOop());
   732   call_class_initializer_impl(ik, THREAD);
   733 }
   735 static int call_class_initializer_impl_counter = 0;   // for debugging
   737 methodOop instanceKlass::class_initializer() {
   738   methodOop clinit = find_method(
   739       vmSymbols::class_initializer_name(), vmSymbols::void_method_signature());
   740   if (clinit != NULL && clinit->has_valid_initializer_flags()) {
   741     return clinit;
   742   }
   743   return NULL;
   744 }
   746 void instanceKlass::call_class_initializer_impl(instanceKlassHandle this_oop, TRAPS) {
   747   methodHandle h_method(THREAD, this_oop->class_initializer());
   748   assert(!this_oop->is_initialized(), "we cannot initialize twice");
   749   if (TraceClassInitialization) {
   750     tty->print("%d Initializing ", call_class_initializer_impl_counter++);
   751     this_oop->name()->print_value();
   752     tty->print_cr("%s (" INTPTR_FORMAT ")", h_method() == NULL ? "(no method)" : "", (address)this_oop());
   753   }
   754   if (h_method() != NULL) {
   755     JavaCallArguments args; // No arguments
   756     JavaValue result(T_VOID);
   757     JavaCalls::call(&result, h_method, &args, CHECK); // Static call (no args)
   758   }
   759 }
   762 void instanceKlass::mask_for(methodHandle method, int bci,
   763   InterpreterOopMap* entry_for) {
   764   // Dirty read, then double-check under a lock.
   765   if (_oop_map_cache == NULL) {
   766     // Otherwise, allocate a new one.
   767     MutexLocker x(OopMapCacheAlloc_lock);
   768     // First time use. Allocate a cache in C heap
   769     if (_oop_map_cache == NULL) {
   770       _oop_map_cache = new OopMapCache();
   771     }
   772   }
   773   // _oop_map_cache is constant after init; lookup below does is own locking.
   774   _oop_map_cache->lookup(method, bci, entry_for);
   775 }
   778 bool instanceKlass::find_local_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
   779   const int n = fields()->length();
   780   for (int i = 0; i < n; i += next_offset ) {
   781     int name_index = fields()->ushort_at(i + name_index_offset);
   782     int sig_index  = fields()->ushort_at(i + signature_index_offset);
   783     Symbol* f_name = constants()->symbol_at(name_index);
   784     Symbol* f_sig  = constants()->symbol_at(sig_index);
   785     if (f_name == name && f_sig == sig) {
   786       fd->initialize(as_klassOop(), i);
   787       return true;
   788     }
   789   }
   790   return false;
   791 }
   794 void instanceKlass::shared_symbols_iterate(SymbolClosure* closure) {
   795   Klass::shared_symbols_iterate(closure);
   796   closure->do_symbol(&_generic_signature);
   797   closure->do_symbol(&_source_file_name);
   798   closure->do_symbol(&_source_debug_extension);
   800   const int n = fields()->length();
   801   for (int i = 0; i < n; i += next_offset ) {
   802     int name_index = fields()->ushort_at(i + name_index_offset);
   803     closure->do_symbol(constants()->symbol_at_addr(name_index));
   804     int sig_index  = fields()->ushort_at(i + signature_index_offset);
   805     closure->do_symbol(constants()->symbol_at_addr(sig_index));
   806   }
   807 }
   810 klassOop instanceKlass::find_interface_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
   811   const int n = local_interfaces()->length();
   812   for (int i = 0; i < n; i++) {
   813     klassOop intf1 = klassOop(local_interfaces()->obj_at(i));
   814     assert(Klass::cast(intf1)->is_interface(), "just checking type");
   815     // search for field in current interface
   816     if (instanceKlass::cast(intf1)->find_local_field(name, sig, fd)) {
   817       assert(fd->is_static(), "interface field must be static");
   818       return intf1;
   819     }
   820     // search for field in direct superinterfaces
   821     klassOop intf2 = instanceKlass::cast(intf1)->find_interface_field(name, sig, fd);
   822     if (intf2 != NULL) return intf2;
   823   }
   824   // otherwise field lookup fails
   825   return NULL;
   826 }
   829 klassOop instanceKlass::find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
   830   // search order according to newest JVM spec (5.4.3.2, p.167).
   831   // 1) search for field in current klass
   832   if (find_local_field(name, sig, fd)) {
   833     return as_klassOop();
   834   }
   835   // 2) search for field recursively in direct superinterfaces
   836   { klassOop intf = find_interface_field(name, sig, fd);
   837     if (intf != NULL) return intf;
   838   }
   839   // 3) apply field lookup recursively if superclass exists
   840   { klassOop supr = super();
   841     if (supr != NULL) return instanceKlass::cast(supr)->find_field(name, sig, fd);
   842   }
   843   // 4) otherwise field lookup fails
   844   return NULL;
   845 }
   848 klassOop instanceKlass::find_field(Symbol* name, Symbol* sig, bool is_static, fieldDescriptor* fd) const {
   849   // search order according to newest JVM spec (5.4.3.2, p.167).
   850   // 1) search for field in current klass
   851   if (find_local_field(name, sig, fd)) {
   852     if (fd->is_static() == is_static) return as_klassOop();
   853   }
   854   // 2) search for field recursively in direct superinterfaces
   855   if (is_static) {
   856     klassOop intf = find_interface_field(name, sig, fd);
   857     if (intf != NULL) return intf;
   858   }
   859   // 3) apply field lookup recursively if superclass exists
   860   { klassOop supr = super();
   861     if (supr != NULL) return instanceKlass::cast(supr)->find_field(name, sig, is_static, fd);
   862   }
   863   // 4) otherwise field lookup fails
   864   return NULL;
   865 }
   868 bool instanceKlass::find_local_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const {
   869   int length = fields()->length();
   870   for (int i = 0; i < length; i += next_offset) {
   871     if (offset_from_fields( i ) == offset) {
   872       fd->initialize(as_klassOop(), i);
   873       if (fd->is_static() == is_static) return true;
   874     }
   875   }
   876   return false;
   877 }
   880 bool instanceKlass::find_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const {
   881   klassOop klass = as_klassOop();
   882   while (klass != NULL) {
   883     if (instanceKlass::cast(klass)->find_local_field_from_offset(offset, is_static, fd)) {
   884       return true;
   885     }
   886     klass = Klass::cast(klass)->super();
   887   }
   888   return false;
   889 }
   892 void instanceKlass::methods_do(void f(methodOop method)) {
   893   int len = methods()->length();
   894   for (int index = 0; index < len; index++) {
   895     methodOop m = methodOop(methods()->obj_at(index));
   896     assert(m->is_method(), "must be method");
   897     f(m);
   898   }
   899 }
   901 void instanceKlass::do_local_static_fields(FieldClosure* cl) {
   902   fieldDescriptor fd;
   903   int length = fields()->length();
   904   for (int i = 0; i < length; i += next_offset) {
   905     fd.initialize(as_klassOop(), i);
   906     if (fd.is_static()) cl->do_field(&fd);
   907   }
   908 }
   911 void instanceKlass::do_local_static_fields(void f(fieldDescriptor*, TRAPS), TRAPS) {
   912   instanceKlassHandle h_this(THREAD, as_klassOop());
   913   do_local_static_fields_impl(h_this, f, CHECK);
   914 }
   917 void instanceKlass::do_local_static_fields_impl(instanceKlassHandle this_oop, void f(fieldDescriptor* fd, TRAPS), TRAPS) {
   918   fieldDescriptor fd;
   919   int length = this_oop->fields()->length();
   920   for (int i = 0; i < length; i += next_offset) {
   921     fd.initialize(this_oop(), i);
   922     if (fd.is_static()) { f(&fd, CHECK); } // Do NOT remove {}! (CHECK macro expands into several statements)
   923   }
   924 }
   927 static int compare_fields_by_offset(int* a, int* b) {
   928   return a[0] - b[0];
   929 }
   931 void instanceKlass::do_nonstatic_fields(FieldClosure* cl) {
   932   instanceKlass* super = superklass();
   933   if (super != NULL) {
   934     super->do_nonstatic_fields(cl);
   935   }
   936   fieldDescriptor fd;
   937   int length = fields()->length();
   938   // In DebugInfo nonstatic fields are sorted by offset.
   939   int* fields_sorted = NEW_C_HEAP_ARRAY(int, 2*(length+1));
   940   int j = 0;
   941   for (int i = 0; i < length; i += next_offset) {
   942     fd.initialize(as_klassOop(), i);
   943     if (!fd.is_static()) {
   944       fields_sorted[j + 0] = fd.offset();
   945       fields_sorted[j + 1] = i;
   946       j += 2;
   947     }
   948   }
   949   if (j > 0) {
   950     length = j;
   951     // _sort_Fn is defined in growableArray.hpp.
   952     qsort(fields_sorted, length/2, 2*sizeof(int), (_sort_Fn)compare_fields_by_offset);
   953     for (int i = 0; i < length; i += 2) {
   954       fd.initialize(as_klassOop(), fields_sorted[i + 1]);
   955       assert(!fd.is_static() && fd.offset() == fields_sorted[i], "only nonstatic fields");
   956       cl->do_field(&fd);
   957     }
   958   }
   959   FREE_C_HEAP_ARRAY(int, fields_sorted);
   960 }
   963 void instanceKlass::array_klasses_do(void f(klassOop k)) {
   964   if (array_klasses() != NULL)
   965     arrayKlass::cast(array_klasses())->array_klasses_do(f);
   966 }
   969 void instanceKlass::with_array_klasses_do(void f(klassOop k)) {
   970   f(as_klassOop());
   971   array_klasses_do(f);
   972 }
   974 #ifdef ASSERT
   975 static int linear_search(objArrayOop methods, Symbol* name, Symbol* signature) {
   976   int len = methods->length();
   977   for (int index = 0; index < len; index++) {
   978     methodOop m = (methodOop)(methods->obj_at(index));
   979     assert(m->is_method(), "must be method");
   980     if (m->signature() == signature && m->name() == name) {
   981        return index;
   982     }
   983   }
   984   return -1;
   985 }
   986 #endif
   988 methodOop instanceKlass::find_method(Symbol* name, Symbol* signature) const {
   989   return instanceKlass::find_method(methods(), name, signature);
   990 }
   992 methodOop instanceKlass::find_method(objArrayOop methods, Symbol* name, Symbol* signature) {
   993   int len = methods->length();
   994   // methods are sorted, so do binary search
   995   int l = 0;
   996   int h = len - 1;
   997   while (l <= h) {
   998     int mid = (l + h) >> 1;
   999     methodOop m = (methodOop)methods->obj_at(mid);
  1000     assert(m->is_method(), "must be method");
  1001     int res = m->name()->fast_compare(name);
  1002     if (res == 0) {
  1003       // found matching name; do linear search to find matching signature
  1004       // first, quick check for common case
  1005       if (m->signature() == signature) return m;
  1006       // search downwards through overloaded methods
  1007       int i;
  1008       for (i = mid - 1; i >= l; i--) {
  1009         methodOop m = (methodOop)methods->obj_at(i);
  1010         assert(m->is_method(), "must be method");
  1011         if (m->name() != name) break;
  1012         if (m->signature() == signature) return m;
  1014       // search upwards
  1015       for (i = mid + 1; i <= h; i++) {
  1016         methodOop m = (methodOop)methods->obj_at(i);
  1017         assert(m->is_method(), "must be method");
  1018         if (m->name() != name) break;
  1019         if (m->signature() == signature) return m;
  1021       // not found
  1022 #ifdef ASSERT
  1023       int index = linear_search(methods, name, signature);
  1024       assert(index == -1, err_msg("binary search should have found entry %d", index));
  1025 #endif
  1026       return NULL;
  1027     } else if (res < 0) {
  1028       l = mid + 1;
  1029     } else {
  1030       h = mid - 1;
  1033 #ifdef ASSERT
  1034   int index = linear_search(methods, name, signature);
  1035   assert(index == -1, err_msg("binary search should have found entry %d", index));
  1036 #endif
  1037   return NULL;
  1040 methodOop instanceKlass::uncached_lookup_method(Symbol* name, Symbol* signature) const {
  1041   klassOop klass = as_klassOop();
  1042   while (klass != NULL) {
  1043     methodOop method = instanceKlass::cast(klass)->find_method(name, signature);
  1044     if (method != NULL) return method;
  1045     klass = instanceKlass::cast(klass)->super();
  1047   return NULL;
  1050 // lookup a method in all the interfaces that this class implements
  1051 methodOop instanceKlass::lookup_method_in_all_interfaces(Symbol* name,
  1052                                                          Symbol* signature) const {
  1053   objArrayOop all_ifs = instanceKlass::cast(as_klassOop())->transitive_interfaces();
  1054   int num_ifs = all_ifs->length();
  1055   instanceKlass *ik = NULL;
  1056   for (int i = 0; i < num_ifs; i++) {
  1057     ik = instanceKlass::cast(klassOop(all_ifs->obj_at(i)));
  1058     methodOop m = ik->lookup_method(name, signature);
  1059     if (m != NULL) {
  1060       return m;
  1063   return NULL;
  1066 /* jni_id_for_impl for jfieldIds only */
  1067 JNIid* instanceKlass::jni_id_for_impl(instanceKlassHandle this_oop, int offset) {
  1068   MutexLocker ml(JfieldIdCreation_lock);
  1069   // Retry lookup after we got the lock
  1070   JNIid* probe = this_oop->jni_ids() == NULL ? NULL : this_oop->jni_ids()->find(offset);
  1071   if (probe == NULL) {
  1072     // Slow case, allocate new static field identifier
  1073     probe = new JNIid(this_oop->as_klassOop(), offset, this_oop->jni_ids());
  1074     this_oop->set_jni_ids(probe);
  1076   return probe;
  1080 /* jni_id_for for jfieldIds only */
  1081 JNIid* instanceKlass::jni_id_for(int offset) {
  1082   JNIid* probe = jni_ids() == NULL ? NULL : jni_ids()->find(offset);
  1083   if (probe == NULL) {
  1084     probe = jni_id_for_impl(this->as_klassOop(), offset);
  1086   return probe;
  1090 // Lookup or create a jmethodID.
  1091 // This code is called by the VMThread and JavaThreads so the
  1092 // locking has to be done very carefully to avoid deadlocks
  1093 // and/or other cache consistency problems.
  1094 //
  1095 jmethodID instanceKlass::get_jmethod_id(instanceKlassHandle ik_h, methodHandle method_h) {
  1096   size_t idnum = (size_t)method_h->method_idnum();
  1097   jmethodID* jmeths = ik_h->methods_jmethod_ids_acquire();
  1098   size_t length = 0;
  1099   jmethodID id = NULL;
  1101   // We use a double-check locking idiom here because this cache is
  1102   // performance sensitive. In the normal system, this cache only
  1103   // transitions from NULL to non-NULL which is safe because we use
  1104   // release_set_methods_jmethod_ids() to advertise the new cache.
  1105   // A partially constructed cache should never be seen by a racing
  1106   // thread. We also use release_store_ptr() to save a new jmethodID
  1107   // in the cache so a partially constructed jmethodID should never be
  1108   // seen either. Cache reads of existing jmethodIDs proceed without a
  1109   // lock, but cache writes of a new jmethodID requires uniqueness and
  1110   // creation of the cache itself requires no leaks so a lock is
  1111   // generally acquired in those two cases.
  1112   //
  1113   // If the RedefineClasses() API has been used, then this cache can
  1114   // grow and we'll have transitions from non-NULL to bigger non-NULL.
  1115   // Cache creation requires no leaks and we require safety between all
  1116   // cache accesses and freeing of the old cache so a lock is generally
  1117   // acquired when the RedefineClasses() API has been used.
  1119   if (jmeths != NULL) {
  1120     // the cache already exists
  1121     if (!ik_h->idnum_can_increment()) {
  1122       // the cache can't grow so we can just get the current values
  1123       get_jmethod_id_length_value(jmeths, idnum, &length, &id);
  1124     } else {
  1125       // cache can grow so we have to be more careful
  1126       if (Threads::number_of_threads() == 0 ||
  1127           SafepointSynchronize::is_at_safepoint()) {
  1128         // we're single threaded or at a safepoint - no locking needed
  1129         get_jmethod_id_length_value(jmeths, idnum, &length, &id);
  1130       } else {
  1131         MutexLocker ml(JmethodIdCreation_lock);
  1132         get_jmethod_id_length_value(jmeths, idnum, &length, &id);
  1136   // implied else:
  1137   // we need to allocate a cache so default length and id values are good
  1139   if (jmeths == NULL ||   // no cache yet
  1140       length <= idnum ||  // cache is too short
  1141       id == NULL) {       // cache doesn't contain entry
  1143     // This function can be called by the VMThread so we have to do all
  1144     // things that might block on a safepoint before grabbing the lock.
  1145     // Otherwise, we can deadlock with the VMThread or have a cache
  1146     // consistency issue. These vars keep track of what we might have
  1147     // to free after the lock is dropped.
  1148     jmethodID  to_dealloc_id     = NULL;
  1149     jmethodID* to_dealloc_jmeths = NULL;
  1151     // may not allocate new_jmeths or use it if we allocate it
  1152     jmethodID* new_jmeths = NULL;
  1153     if (length <= idnum) {
  1154       // allocate a new cache that might be used
  1155       size_t size = MAX2(idnum+1, (size_t)ik_h->idnum_allocated_count());
  1156       new_jmeths = NEW_C_HEAP_ARRAY(jmethodID, size+1);
  1157       memset(new_jmeths, 0, (size+1)*sizeof(jmethodID));
  1158       // cache size is stored in element[0], other elements offset by one
  1159       new_jmeths[0] = (jmethodID)size;
  1162     // allocate a new jmethodID that might be used
  1163     jmethodID new_id = NULL;
  1164     if (method_h->is_old() && !method_h->is_obsolete()) {
  1165       // The method passed in is old (but not obsolete), we need to use the current version
  1166       methodOop current_method = ik_h->method_with_idnum((int)idnum);
  1167       assert(current_method != NULL, "old and but not obsolete, so should exist");
  1168       methodHandle current_method_h(current_method == NULL? method_h() : current_method);
  1169       new_id = JNIHandles::make_jmethod_id(current_method_h);
  1170     } else {
  1171       // It is the current version of the method or an obsolete method,
  1172       // use the version passed in
  1173       new_id = JNIHandles::make_jmethod_id(method_h);
  1176     if (Threads::number_of_threads() == 0 ||
  1177         SafepointSynchronize::is_at_safepoint()) {
  1178       // we're single threaded or at a safepoint - no locking needed
  1179       id = get_jmethod_id_fetch_or_update(ik_h, idnum, new_id, new_jmeths,
  1180                                           &to_dealloc_id, &to_dealloc_jmeths);
  1181     } else {
  1182       MutexLocker ml(JmethodIdCreation_lock);
  1183       id = get_jmethod_id_fetch_or_update(ik_h, idnum, new_id, new_jmeths,
  1184                                           &to_dealloc_id, &to_dealloc_jmeths);
  1187     // The lock has been dropped so we can free resources.
  1188     // Free up either the old cache or the new cache if we allocated one.
  1189     if (to_dealloc_jmeths != NULL) {
  1190       FreeHeap(to_dealloc_jmeths);
  1192     // free up the new ID since it wasn't needed
  1193     if (to_dealloc_id != NULL) {
  1194       JNIHandles::destroy_jmethod_id(to_dealloc_id);
  1197   return id;
  1201 // Common code to fetch the jmethodID from the cache or update the
  1202 // cache with the new jmethodID. This function should never do anything
  1203 // that causes the caller to go to a safepoint or we can deadlock with
  1204 // the VMThread or have cache consistency issues.
  1205 //
  1206 jmethodID instanceKlass::get_jmethod_id_fetch_or_update(
  1207             instanceKlassHandle ik_h, size_t idnum, jmethodID new_id,
  1208             jmethodID* new_jmeths, jmethodID* to_dealloc_id_p,
  1209             jmethodID** to_dealloc_jmeths_p) {
  1210   assert(new_id != NULL, "sanity check");
  1211   assert(to_dealloc_id_p != NULL, "sanity check");
  1212   assert(to_dealloc_jmeths_p != NULL, "sanity check");
  1213   assert(Threads::number_of_threads() == 0 ||
  1214          SafepointSynchronize::is_at_safepoint() ||
  1215          JmethodIdCreation_lock->owned_by_self(), "sanity check");
  1217   // reacquire the cache - we are locked, single threaded or at a safepoint
  1218   jmethodID* jmeths = ik_h->methods_jmethod_ids_acquire();
  1219   jmethodID  id     = NULL;
  1220   size_t     length = 0;
  1222   if (jmeths == NULL ||                         // no cache yet
  1223       (length = (size_t)jmeths[0]) <= idnum) {  // cache is too short
  1224     if (jmeths != NULL) {
  1225       // copy any existing entries from the old cache
  1226       for (size_t index = 0; index < length; index++) {
  1227         new_jmeths[index+1] = jmeths[index+1];
  1229       *to_dealloc_jmeths_p = jmeths;  // save old cache for later delete
  1231     ik_h->release_set_methods_jmethod_ids(jmeths = new_jmeths);
  1232   } else {
  1233     // fetch jmethodID (if any) from the existing cache
  1234     id = jmeths[idnum+1];
  1235     *to_dealloc_jmeths_p = new_jmeths;  // save new cache for later delete
  1237   if (id == NULL) {
  1238     // No matching jmethodID in the existing cache or we have a new
  1239     // cache or we just grew the cache. This cache write is done here
  1240     // by the first thread to win the foot race because a jmethodID
  1241     // needs to be unique once it is generally available.
  1242     id = new_id;
  1244     // The jmethodID cache can be read while unlocked so we have to
  1245     // make sure the new jmethodID is complete before installing it
  1246     // in the cache.
  1247     OrderAccess::release_store_ptr(&jmeths[idnum+1], id);
  1248   } else {
  1249     *to_dealloc_id_p = new_id; // save new id for later delete
  1251   return id;
  1255 // Common code to get the jmethodID cache length and the jmethodID
  1256 // value at index idnum if there is one.
  1257 //
  1258 void instanceKlass::get_jmethod_id_length_value(jmethodID* cache,
  1259        size_t idnum, size_t *length_p, jmethodID* id_p) {
  1260   assert(cache != NULL, "sanity check");
  1261   assert(length_p != NULL, "sanity check");
  1262   assert(id_p != NULL, "sanity check");
  1264   // cache size is stored in element[0], other elements offset by one
  1265   *length_p = (size_t)cache[0];
  1266   if (*length_p <= idnum) {  // cache is too short
  1267     *id_p = NULL;
  1268   } else {
  1269     *id_p = cache[idnum+1];  // fetch jmethodID (if any)
  1274 // Lookup a jmethodID, NULL if not found.  Do no blocking, no allocations, no handles
  1275 jmethodID instanceKlass::jmethod_id_or_null(methodOop method) {
  1276   size_t idnum = (size_t)method->method_idnum();
  1277   jmethodID* jmeths = methods_jmethod_ids_acquire();
  1278   size_t length;                                // length assigned as debugging crumb
  1279   jmethodID id = NULL;
  1280   if (jmeths != NULL &&                         // If there is a cache
  1281       (length = (size_t)jmeths[0]) > idnum) {   // and if it is long enough,
  1282     id = jmeths[idnum+1];                       // Look up the id (may be NULL)
  1284   return id;
  1288 // Cache an itable index
  1289 void instanceKlass::set_cached_itable_index(size_t idnum, int index) {
  1290   int* indices = methods_cached_itable_indices_acquire();
  1291   int* to_dealloc_indices = NULL;
  1293   // We use a double-check locking idiom here because this cache is
  1294   // performance sensitive. In the normal system, this cache only
  1295   // transitions from NULL to non-NULL which is safe because we use
  1296   // release_set_methods_cached_itable_indices() to advertise the
  1297   // new cache. A partially constructed cache should never be seen
  1298   // by a racing thread. Cache reads and writes proceed without a
  1299   // lock, but creation of the cache itself requires no leaks so a
  1300   // lock is generally acquired in that case.
  1301   //
  1302   // If the RedefineClasses() API has been used, then this cache can
  1303   // grow and we'll have transitions from non-NULL to bigger non-NULL.
  1304   // Cache creation requires no leaks and we require safety between all
  1305   // cache accesses and freeing of the old cache so a lock is generally
  1306   // acquired when the RedefineClasses() API has been used.
  1308   if (indices == NULL || idnum_can_increment()) {
  1309     // we need a cache or the cache can grow
  1310     MutexLocker ml(JNICachedItableIndex_lock);
  1311     // reacquire the cache to see if another thread already did the work
  1312     indices = methods_cached_itable_indices_acquire();
  1313     size_t length = 0;
  1314     // cache size is stored in element[0], other elements offset by one
  1315     if (indices == NULL || (length = (size_t)indices[0]) <= idnum) {
  1316       size_t size = MAX2(idnum+1, (size_t)idnum_allocated_count());
  1317       int* new_indices = NEW_C_HEAP_ARRAY(int, size+1);
  1318       new_indices[0] = (int)size;
  1319       // copy any existing entries
  1320       size_t i;
  1321       for (i = 0; i < length; i++) {
  1322         new_indices[i+1] = indices[i+1];
  1324       // Set all the rest to -1
  1325       for (i = length; i < size; i++) {
  1326         new_indices[i+1] = -1;
  1328       if (indices != NULL) {
  1329         // We have an old cache to delete so save it for after we
  1330         // drop the lock.
  1331         to_dealloc_indices = indices;
  1333       release_set_methods_cached_itable_indices(indices = new_indices);
  1336     if (idnum_can_increment()) {
  1337       // this cache can grow so we have to write to it safely
  1338       indices[idnum+1] = index;
  1340   } else {
  1341     CHECK_UNHANDLED_OOPS_ONLY(Thread::current()->clear_unhandled_oops());
  1344   if (!idnum_can_increment()) {
  1345     // The cache cannot grow and this JNI itable index value does not
  1346     // have to be unique like a jmethodID. If there is a race to set it,
  1347     // it doesn't matter.
  1348     indices[idnum+1] = index;
  1351   if (to_dealloc_indices != NULL) {
  1352     // we allocated a new cache so free the old one
  1353     FreeHeap(to_dealloc_indices);
  1358 // Retrieve a cached itable index
  1359 int instanceKlass::cached_itable_index(size_t idnum) {
  1360   int* indices = methods_cached_itable_indices_acquire();
  1361   if (indices != NULL && ((size_t)indices[0]) > idnum) {
  1362      // indices exist and are long enough, retrieve possible cached
  1363     return indices[idnum+1];
  1365   return -1;
  1369 //
  1370 // nmethodBucket is used to record dependent nmethods for
  1371 // deoptimization.  nmethod dependencies are actually <klass, method>
  1372 // pairs but we really only care about the klass part for purposes of
  1373 // finding nmethods which might need to be deoptimized.  Instead of
  1374 // recording the method, a count of how many times a particular nmethod
  1375 // was recorded is kept.  This ensures that any recording errors are
  1376 // noticed since an nmethod should be removed as many times are it's
  1377 // added.
  1378 //
  1379 class nmethodBucket {
  1380  private:
  1381   nmethod*       _nmethod;
  1382   int            _count;
  1383   nmethodBucket* _next;
  1385  public:
  1386   nmethodBucket(nmethod* nmethod, nmethodBucket* next) {
  1387     _nmethod = nmethod;
  1388     _next = next;
  1389     _count = 1;
  1391   int count()                             { return _count; }
  1392   int increment()                         { _count += 1; return _count; }
  1393   int decrement()                         { _count -= 1; assert(_count >= 0, "don't underflow"); return _count; }
  1394   nmethodBucket* next()                   { return _next; }
  1395   void set_next(nmethodBucket* b)         { _next = b; }
  1396   nmethod* get_nmethod()                  { return _nmethod; }
  1397 };
  1400 //
  1401 // Walk the list of dependent nmethods searching for nmethods which
  1402 // are dependent on the klassOop that was passed in and mark them for
  1403 // deoptimization.  Returns the number of nmethods found.
  1404 //
  1405 int instanceKlass::mark_dependent_nmethods(DepChange& changes) {
  1406   assert_locked_or_safepoint(CodeCache_lock);
  1407   int found = 0;
  1408   nmethodBucket* b = _dependencies;
  1409   while (b != NULL) {
  1410     nmethod* nm = b->get_nmethod();
  1411     // since dependencies aren't removed until an nmethod becomes a zombie,
  1412     // the dependency list may contain nmethods which aren't alive.
  1413     if (nm->is_alive() && !nm->is_marked_for_deoptimization() && nm->check_dependency_on(changes)) {
  1414       if (TraceDependencies) {
  1415         ResourceMark rm;
  1416         tty->print_cr("Marked for deoptimization");
  1417         tty->print_cr("  context = %s", this->external_name());
  1418         changes.print();
  1419         nm->print();
  1420         nm->print_dependencies();
  1422       nm->mark_for_deoptimization();
  1423       found++;
  1425     b = b->next();
  1427   return found;
  1431 //
  1432 // Add an nmethodBucket to the list of dependencies for this nmethod.
  1433 // It's possible that an nmethod has multiple dependencies on this klass
  1434 // so a count is kept for each bucket to guarantee that creation and
  1435 // deletion of dependencies is consistent.
  1436 //
  1437 void instanceKlass::add_dependent_nmethod(nmethod* nm) {
  1438   assert_locked_or_safepoint(CodeCache_lock);
  1439   nmethodBucket* b = _dependencies;
  1440   nmethodBucket* last = NULL;
  1441   while (b != NULL) {
  1442     if (nm == b->get_nmethod()) {
  1443       b->increment();
  1444       return;
  1446     b = b->next();
  1448   _dependencies = new nmethodBucket(nm, _dependencies);
  1452 //
  1453 // Decrement count of the nmethod in the dependency list and remove
  1454 // the bucket competely when the count goes to 0.  This method must
  1455 // find a corresponding bucket otherwise there's a bug in the
  1456 // recording of dependecies.
  1457 //
  1458 void instanceKlass::remove_dependent_nmethod(nmethod* nm) {
  1459   assert_locked_or_safepoint(CodeCache_lock);
  1460   nmethodBucket* b = _dependencies;
  1461   nmethodBucket* last = NULL;
  1462   while (b != NULL) {
  1463     if (nm == b->get_nmethod()) {
  1464       if (b->decrement() == 0) {
  1465         if (last == NULL) {
  1466           _dependencies = b->next();
  1467         } else {
  1468           last->set_next(b->next());
  1470         delete b;
  1472       return;
  1474     last = b;
  1475     b = b->next();
  1477 #ifdef ASSERT
  1478   tty->print_cr("### %s can't find dependent nmethod:", this->external_name());
  1479   nm->print();
  1480 #endif // ASSERT
  1481   ShouldNotReachHere();
  1485 #ifndef PRODUCT
  1486 void instanceKlass::print_dependent_nmethods(bool verbose) {
  1487   nmethodBucket* b = _dependencies;
  1488   int idx = 0;
  1489   while (b != NULL) {
  1490     nmethod* nm = b->get_nmethod();
  1491     tty->print("[%d] count=%d { ", idx++, b->count());
  1492     if (!verbose) {
  1493       nm->print_on(tty, "nmethod");
  1494       tty->print_cr(" } ");
  1495     } else {
  1496       nm->print();
  1497       nm->print_dependencies();
  1498       tty->print_cr("--- } ");
  1500     b = b->next();
  1505 bool instanceKlass::is_dependent_nmethod(nmethod* nm) {
  1506   nmethodBucket* b = _dependencies;
  1507   while (b != NULL) {
  1508     if (nm == b->get_nmethod()) {
  1509       return true;
  1511     b = b->next();
  1513   return false;
  1515 #endif //PRODUCT
  1518 #ifdef ASSERT
  1519 template <class T> void assert_is_in(T *p) {
  1520   T heap_oop = oopDesc::load_heap_oop(p);
  1521   if (!oopDesc::is_null(heap_oop)) {
  1522     oop o = oopDesc::decode_heap_oop_not_null(heap_oop);
  1523     assert(Universe::heap()->is_in(o), "should be in heap");
  1526 template <class T> void assert_is_in_closed_subset(T *p) {
  1527   T heap_oop = oopDesc::load_heap_oop(p);
  1528   if (!oopDesc::is_null(heap_oop)) {
  1529     oop o = oopDesc::decode_heap_oop_not_null(heap_oop);
  1530     assert(Universe::heap()->is_in_closed_subset(o), "should be in closed");
  1533 template <class T> void assert_is_in_reserved(T *p) {
  1534   T heap_oop = oopDesc::load_heap_oop(p);
  1535   if (!oopDesc::is_null(heap_oop)) {
  1536     oop o = oopDesc::decode_heap_oop_not_null(heap_oop);
  1537     assert(Universe::heap()->is_in_reserved(o), "should be in reserved");
  1540 template <class T> void assert_nothing(T *p) {}
  1542 #else
  1543 template <class T> void assert_is_in(T *p) {}
  1544 template <class T> void assert_is_in_closed_subset(T *p) {}
  1545 template <class T> void assert_is_in_reserved(T *p) {}
  1546 template <class T> void assert_nothing(T *p) {}
  1547 #endif // ASSERT
  1549 //
  1550 // Macros that iterate over areas of oops which are specialized on type of
  1551 // oop pointer either narrow or wide, depending on UseCompressedOops
  1552 //
  1553 // Parameters are:
  1554 //   T         - type of oop to point to (either oop or narrowOop)
  1555 //   start_p   - starting pointer for region to iterate over
  1556 //   count     - number of oops or narrowOops to iterate over
  1557 //   do_oop    - action to perform on each oop (it's arbitrary C code which
  1558 //               makes it more efficient to put in a macro rather than making
  1559 //               it a template function)
  1560 //   assert_fn - assert function which is template function because performance
  1561 //               doesn't matter when enabled.
  1562 #define InstanceKlass_SPECIALIZED_OOP_ITERATE( \
  1563   T, start_p, count, do_oop,                \
  1564   assert_fn)                                \
  1565 {                                           \
  1566   T* p         = (T*)(start_p);             \
  1567   T* const end = p + (count);               \
  1568   while (p < end) {                         \
  1569     (assert_fn)(p);                         \
  1570     do_oop;                                 \
  1571     ++p;                                    \
  1572   }                                         \
  1575 #define InstanceKlass_SPECIALIZED_OOP_REVERSE_ITERATE( \
  1576   T, start_p, count, do_oop,                \
  1577   assert_fn)                                \
  1578 {                                           \
  1579   T* const start = (T*)(start_p);           \
  1580   T*       p     = start + (count);         \
  1581   while (start < p) {                       \
  1582     --p;                                    \
  1583     (assert_fn)(p);                         \
  1584     do_oop;                                 \
  1585   }                                         \
  1588 #define InstanceKlass_SPECIALIZED_BOUNDED_OOP_ITERATE( \
  1589   T, start_p, count, low, high,             \
  1590   do_oop, assert_fn)                        \
  1591 {                                           \
  1592   T* const l = (T*)(low);                   \
  1593   T* const h = (T*)(high);                  \
  1594   assert(mask_bits((intptr_t)l, sizeof(T)-1) == 0 && \
  1595          mask_bits((intptr_t)h, sizeof(T)-1) == 0,   \
  1596          "bounded region must be properly aligned"); \
  1597   T* p       = (T*)(start_p);               \
  1598   T* end     = p + (count);                 \
  1599   if (p < l) p = l;                         \
  1600   if (end > h) end = h;                     \
  1601   while (p < end) {                         \
  1602     (assert_fn)(p);                         \
  1603     do_oop;                                 \
  1604     ++p;                                    \
  1605   }                                         \
  1609 // The following macros call specialized macros, passing either oop or
  1610 // narrowOop as the specialization type.  These test the UseCompressedOops
  1611 // flag.
  1612 #define InstanceKlass_OOP_ITERATE(start_p, count,    \
  1613                                   do_oop, assert_fn) \
  1614 {                                                    \
  1615   if (UseCompressedOops) {                           \
  1616     InstanceKlass_SPECIALIZED_OOP_ITERATE(narrowOop, \
  1617       start_p, count,                                \
  1618       do_oop, assert_fn)                             \
  1619   } else {                                           \
  1620     InstanceKlass_SPECIALIZED_OOP_ITERATE(oop,       \
  1621       start_p, count,                                \
  1622       do_oop, assert_fn)                             \
  1623   }                                                  \
  1626 #define InstanceKlass_BOUNDED_OOP_ITERATE(start_p, count, low, high,    \
  1627                                           do_oop, assert_fn) \
  1628 {                                                            \
  1629   if (UseCompressedOops) {                                   \
  1630     InstanceKlass_SPECIALIZED_BOUNDED_OOP_ITERATE(narrowOop, \
  1631       start_p, count,                                        \
  1632       low, high,                                             \
  1633       do_oop, assert_fn)                                     \
  1634   } else {                                                   \
  1635     InstanceKlass_SPECIALIZED_BOUNDED_OOP_ITERATE(oop,       \
  1636       start_p, count,                                        \
  1637       low, high,                                             \
  1638       do_oop, assert_fn)                                     \
  1639   }                                                          \
  1642 #define InstanceKlass_OOP_MAP_ITERATE(obj, do_oop, assert_fn)            \
  1643 {                                                                        \
  1644   /* Compute oopmap block range. The common case                         \
  1645      is nonstatic_oop_map_size == 1. */                                  \
  1646   OopMapBlock* map           = start_of_nonstatic_oop_maps();            \
  1647   OopMapBlock* const end_map = map + nonstatic_oop_map_count();          \
  1648   if (UseCompressedOops) {                                               \
  1649     while (map < end_map) {                                              \
  1650       InstanceKlass_SPECIALIZED_OOP_ITERATE(narrowOop,                   \
  1651         obj->obj_field_addr<narrowOop>(map->offset()), map->count(),     \
  1652         do_oop, assert_fn)                                               \
  1653       ++map;                                                             \
  1654     }                                                                    \
  1655   } else {                                                               \
  1656     while (map < end_map) {                                              \
  1657       InstanceKlass_SPECIALIZED_OOP_ITERATE(oop,                         \
  1658         obj->obj_field_addr<oop>(map->offset()), map->count(),           \
  1659         do_oop, assert_fn)                                               \
  1660       ++map;                                                             \
  1661     }                                                                    \
  1662   }                                                                      \
  1665 #define InstanceKlass_OOP_MAP_REVERSE_ITERATE(obj, do_oop, assert_fn)    \
  1666 {                                                                        \
  1667   OopMapBlock* const start_map = start_of_nonstatic_oop_maps();          \
  1668   OopMapBlock* map             = start_map + nonstatic_oop_map_count();  \
  1669   if (UseCompressedOops) {                                               \
  1670     while (start_map < map) {                                            \
  1671       --map;                                                             \
  1672       InstanceKlass_SPECIALIZED_OOP_REVERSE_ITERATE(narrowOop,           \
  1673         obj->obj_field_addr<narrowOop>(map->offset()), map->count(),     \
  1674         do_oop, assert_fn)                                               \
  1675     }                                                                    \
  1676   } else {                                                               \
  1677     while (start_map < map) {                                            \
  1678       --map;                                                             \
  1679       InstanceKlass_SPECIALIZED_OOP_REVERSE_ITERATE(oop,                 \
  1680         obj->obj_field_addr<oop>(map->offset()), map->count(),           \
  1681         do_oop, assert_fn)                                               \
  1682     }                                                                    \
  1683   }                                                                      \
  1686 #define InstanceKlass_BOUNDED_OOP_MAP_ITERATE(obj, low, high, do_oop,    \
  1687                                               assert_fn)                 \
  1688 {                                                                        \
  1689   /* Compute oopmap block range. The common case is                      \
  1690      nonstatic_oop_map_size == 1, so we accept the                       \
  1691      usually non-existent extra overhead of examining                    \
  1692      all the maps. */                                                    \
  1693   OopMapBlock* map           = start_of_nonstatic_oop_maps();            \
  1694   OopMapBlock* const end_map = map + nonstatic_oop_map_count();          \
  1695   if (UseCompressedOops) {                                               \
  1696     while (map < end_map) {                                              \
  1697       InstanceKlass_SPECIALIZED_BOUNDED_OOP_ITERATE(narrowOop,           \
  1698         obj->obj_field_addr<narrowOop>(map->offset()), map->count(),     \
  1699         low, high,                                                       \
  1700         do_oop, assert_fn)                                               \
  1701       ++map;                                                             \
  1702     }                                                                    \
  1703   } else {                                                               \
  1704     while (map < end_map) {                                              \
  1705       InstanceKlass_SPECIALIZED_BOUNDED_OOP_ITERATE(oop,                 \
  1706         obj->obj_field_addr<oop>(map->offset()), map->count(),           \
  1707         low, high,                                                       \
  1708         do_oop, assert_fn)                                               \
  1709       ++map;                                                             \
  1710     }                                                                    \
  1711   }                                                                      \
  1714 void instanceKlass::follow_static_fields() {
  1715   InstanceKlass_OOP_ITERATE( \
  1716     start_of_static_fields(), static_oop_field_size(), \
  1717     MarkSweep::mark_and_push(p), \
  1718     assert_is_in_closed_subset)
  1721 #ifndef SERIALGC
  1722 void instanceKlass::follow_static_fields(ParCompactionManager* cm) {
  1723   InstanceKlass_OOP_ITERATE( \
  1724     start_of_static_fields(), static_oop_field_size(), \
  1725     PSParallelCompact::mark_and_push(cm, p), \
  1726     assert_is_in)
  1728 #endif // SERIALGC
  1730 void instanceKlass::adjust_static_fields() {
  1731   InstanceKlass_OOP_ITERATE( \
  1732     start_of_static_fields(), static_oop_field_size(), \
  1733     MarkSweep::adjust_pointer(p), \
  1734     assert_nothing)
  1737 #ifndef SERIALGC
  1738 void instanceKlass::update_static_fields() {
  1739   InstanceKlass_OOP_ITERATE( \
  1740     start_of_static_fields(), static_oop_field_size(), \
  1741     PSParallelCompact::adjust_pointer(p), \
  1742     assert_nothing)
  1744 #endif // SERIALGC
  1746 void instanceKlass::oop_follow_contents(oop obj) {
  1747   assert(obj != NULL, "can't follow the content of NULL object");
  1748   obj->follow_header();
  1749   InstanceKlass_OOP_MAP_ITERATE( \
  1750     obj, \
  1751     MarkSweep::mark_and_push(p), \
  1752     assert_is_in_closed_subset)
  1755 #ifndef SERIALGC
  1756 void instanceKlass::oop_follow_contents(ParCompactionManager* cm,
  1757                                         oop obj) {
  1758   assert(obj != NULL, "can't follow the content of NULL object");
  1759   obj->follow_header(cm);
  1760   InstanceKlass_OOP_MAP_ITERATE( \
  1761     obj, \
  1762     PSParallelCompact::mark_and_push(cm, p), \
  1763     assert_is_in)
  1765 #endif // SERIALGC
  1767 // closure's do_header() method dicates whether the given closure should be
  1768 // applied to the klass ptr in the object header.
  1770 #define InstanceKlass_OOP_OOP_ITERATE_DEFN(OopClosureType, nv_suffix)        \
  1772 int instanceKlass::oop_oop_iterate##nv_suffix(oop obj, OopClosureType* closure) { \
  1773   SpecializationStats::record_iterate_call##nv_suffix(SpecializationStats::ik);\
  1774   /* header */                                                          \
  1775   if (closure->do_header()) {                                           \
  1776     obj->oop_iterate_header(closure);                                   \
  1777   }                                                                     \
  1778   InstanceKlass_OOP_MAP_ITERATE(                                        \
  1779     obj,                                                                \
  1780     SpecializationStats::                                               \
  1781       record_do_oop_call##nv_suffix(SpecializationStats::ik);           \
  1782     (closure)->do_oop##nv_suffix(p),                                    \
  1783     assert_is_in_closed_subset)                                         \
  1784   return size_helper();                                                 \
  1787 #ifndef SERIALGC
  1788 #define InstanceKlass_OOP_OOP_ITERATE_BACKWARDS_DEFN(OopClosureType, nv_suffix) \
  1790 int instanceKlass::oop_oop_iterate_backwards##nv_suffix(oop obj,                \
  1791                                               OopClosureType* closure) {        \
  1792   SpecializationStats::record_iterate_call##nv_suffix(SpecializationStats::ik); \
  1793   /* header */                                                                  \
  1794   if (closure->do_header()) {                                                   \
  1795     obj->oop_iterate_header(closure);                                           \
  1796   }                                                                             \
  1797   /* instance variables */                                                      \
  1798   InstanceKlass_OOP_MAP_REVERSE_ITERATE(                                        \
  1799     obj,                                                                        \
  1800     SpecializationStats::record_do_oop_call##nv_suffix(SpecializationStats::ik);\
  1801     (closure)->do_oop##nv_suffix(p),                                            \
  1802     assert_is_in_closed_subset)                                                 \
  1803    return size_helper();                                                        \
  1805 #endif // !SERIALGC
  1807 #define InstanceKlass_OOP_OOP_ITERATE_DEFN_m(OopClosureType, nv_suffix) \
  1809 int instanceKlass::oop_oop_iterate##nv_suffix##_m(oop obj,              \
  1810                                                   OopClosureType* closure, \
  1811                                                   MemRegion mr) {          \
  1812   SpecializationStats::record_iterate_call##nv_suffix(SpecializationStats::ik);\
  1813   if (closure->do_header()) {                                            \
  1814     obj->oop_iterate_header(closure, mr);                                \
  1815   }                                                                      \
  1816   InstanceKlass_BOUNDED_OOP_MAP_ITERATE(                                 \
  1817     obj, mr.start(), mr.end(),                                           \
  1818     (closure)->do_oop##nv_suffix(p),                                     \
  1819     assert_is_in_closed_subset)                                          \
  1820   return size_helper();                                                  \
  1823 ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceKlass_OOP_OOP_ITERATE_DEFN)
  1824 ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceKlass_OOP_OOP_ITERATE_DEFN)
  1825 ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceKlass_OOP_OOP_ITERATE_DEFN_m)
  1826 ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceKlass_OOP_OOP_ITERATE_DEFN_m)
  1827 #ifndef SERIALGC
  1828 ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceKlass_OOP_OOP_ITERATE_BACKWARDS_DEFN)
  1829 ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceKlass_OOP_OOP_ITERATE_BACKWARDS_DEFN)
  1830 #endif // !SERIALGC
  1832 void instanceKlass::iterate_static_fields(OopClosure* closure) {
  1833     InstanceKlass_OOP_ITERATE( \
  1834       start_of_static_fields(), static_oop_field_size(), \
  1835       closure->do_oop(p), \
  1836       assert_is_in_reserved)
  1839 void instanceKlass::iterate_static_fields(OopClosure* closure,
  1840                                           MemRegion mr) {
  1841   InstanceKlass_BOUNDED_OOP_ITERATE( \
  1842     start_of_static_fields(), static_oop_field_size(), \
  1843     mr.start(), mr.end(), \
  1844     (closure)->do_oop_v(p), \
  1845     assert_is_in_closed_subset)
  1848 int instanceKlass::oop_adjust_pointers(oop obj) {
  1849   int size = size_helper();
  1850   InstanceKlass_OOP_MAP_ITERATE( \
  1851     obj, \
  1852     MarkSweep::adjust_pointer(p), \
  1853     assert_is_in)
  1854   obj->adjust_header();
  1855   return size;
  1858 #ifndef SERIALGC
  1859 void instanceKlass::oop_push_contents(PSPromotionManager* pm, oop obj) {
  1860   InstanceKlass_OOP_MAP_REVERSE_ITERATE( \
  1861     obj, \
  1862     if (PSScavenge::should_scavenge(p)) { \
  1863       pm->claim_or_forward_depth(p); \
  1864     }, \
  1865     assert_nothing )
  1868 int instanceKlass::oop_update_pointers(ParCompactionManager* cm, oop obj) {
  1869   InstanceKlass_OOP_MAP_ITERATE( \
  1870     obj, \
  1871     PSParallelCompact::adjust_pointer(p), \
  1872     assert_nothing)
  1873   return size_helper();
  1876 void instanceKlass::push_static_fields(PSPromotionManager* pm) {
  1877   InstanceKlass_OOP_ITERATE( \
  1878     start_of_static_fields(), static_oop_field_size(), \
  1879     if (PSScavenge::should_scavenge(p)) { \
  1880       pm->claim_or_forward_depth(p); \
  1881     }, \
  1882     assert_nothing )
  1885 void instanceKlass::copy_static_fields(ParCompactionManager* cm) {
  1886   InstanceKlass_OOP_ITERATE( \
  1887     start_of_static_fields(), static_oop_field_size(), \
  1888     PSParallelCompact::adjust_pointer(p), \
  1889     assert_is_in)
  1891 #endif // SERIALGC
  1893 // This klass is alive but the implementor link is not followed/updated.
  1894 // Subklass and sibling links are handled by Klass::follow_weak_klass_links
  1896 void instanceKlass::follow_weak_klass_links(
  1897   BoolObjectClosure* is_alive, OopClosure* keep_alive) {
  1898   assert(is_alive->do_object_b(as_klassOop()), "this oop should be live");
  1899   if (ClassUnloading) {
  1900     for (int i = 0; i < implementors_limit; i++) {
  1901       klassOop impl = _implementors[i];
  1902       if (impl == NULL)  break;  // no more in the list
  1903       if (!is_alive->do_object_b(impl)) {
  1904         // remove this guy from the list by overwriting him with the tail
  1905         int lasti = --_nof_implementors;
  1906         assert(lasti >= i && lasti < implementors_limit, "just checking");
  1907         _implementors[i] = _implementors[lasti];
  1908         _implementors[lasti] = NULL;
  1909         --i; // rerun the loop at this index
  1912   } else {
  1913     for (int i = 0; i < implementors_limit; i++) {
  1914       keep_alive->do_oop(&adr_implementors()[i]);
  1917   Klass::follow_weak_klass_links(is_alive, keep_alive);
  1920 void instanceKlass::remove_unshareable_info() {
  1921   Klass::remove_unshareable_info();
  1922   init_implementor();
  1925 static void clear_all_breakpoints(methodOop m) {
  1926   m->clear_all_breakpoints();
  1929 void instanceKlass::release_C_heap_structures() {
  1930   // Deallocate oop map cache
  1931   if (_oop_map_cache != NULL) {
  1932     delete _oop_map_cache;
  1933     _oop_map_cache = NULL;
  1936   // Deallocate JNI identifiers for jfieldIDs
  1937   JNIid::deallocate(jni_ids());
  1938   set_jni_ids(NULL);
  1940   jmethodID* jmeths = methods_jmethod_ids_acquire();
  1941   if (jmeths != (jmethodID*)NULL) {
  1942     release_set_methods_jmethod_ids(NULL);
  1943     FreeHeap(jmeths);
  1946   int* indices = methods_cached_itable_indices_acquire();
  1947   if (indices != (int*)NULL) {
  1948     release_set_methods_cached_itable_indices(NULL);
  1949     FreeHeap(indices);
  1952   // release dependencies
  1953   nmethodBucket* b = _dependencies;
  1954   _dependencies = NULL;
  1955   while (b != NULL) {
  1956     nmethodBucket* next = b->next();
  1957     delete b;
  1958     b = next;
  1961   // Deallocate breakpoint records
  1962   if (breakpoints() != 0x0) {
  1963     methods_do(clear_all_breakpoints);
  1964     assert(breakpoints() == 0x0, "should have cleared breakpoints");
  1967   // deallocate information about previous versions
  1968   if (_previous_versions != NULL) {
  1969     for (int i = _previous_versions->length() - 1; i >= 0; i--) {
  1970       PreviousVersionNode * pv_node = _previous_versions->at(i);
  1971       delete pv_node;
  1973     delete _previous_versions;
  1974     _previous_versions = NULL;
  1977   // deallocate the cached class file
  1978   if (_cached_class_file_bytes != NULL) {
  1979     os::free(_cached_class_file_bytes);
  1980     _cached_class_file_bytes = NULL;
  1981     _cached_class_file_len = 0;
  1984   // Decrement symbol reference counts associated with the unloaded class.
  1985   if (_name != NULL) _name->decrement_refcount();
  1986   // unreference array name derived from this class name (arrays of an unloaded
  1987   // class can't be referenced anymore).
  1988   if (_array_name != NULL)  _array_name->decrement_refcount();
  1989   if (_source_file_name != NULL) _source_file_name->decrement_refcount();
  1990   if (_source_debug_extension != NULL) _source_debug_extension->decrement_refcount();
  1991   // walk constant pool and decrement symbol reference counts
  1992   _constants->unreference_symbols();
  1995 void instanceKlass::set_source_file_name(Symbol* n) {
  1996   _source_file_name = n;
  1997   if (_source_file_name != NULL) _source_file_name->increment_refcount();
  2000 void instanceKlass::set_source_debug_extension(Symbol* n) {
  2001   _source_debug_extension = n;
  2002   if (_source_debug_extension != NULL) _source_debug_extension->increment_refcount();
  2005 const char* instanceKlass::signature_name() const {
  2006   const char* src = (const char*) (name()->as_C_string());
  2007   const int src_length = (int)strlen(src);
  2008   char* dest = NEW_RESOURCE_ARRAY(char, src_length + 3);
  2009   int src_index = 0;
  2010   int dest_index = 0;
  2011   dest[dest_index++] = 'L';
  2012   while (src_index < src_length) {
  2013     dest[dest_index++] = src[src_index++];
  2015   dest[dest_index++] = ';';
  2016   dest[dest_index] = '\0';
  2017   return dest;
  2020 // different verisons of is_same_class_package
  2021 bool instanceKlass::is_same_class_package(klassOop class2) {
  2022   klassOop class1 = as_klassOop();
  2023   oop classloader1 = instanceKlass::cast(class1)->class_loader();
  2024   Symbol* classname1 = Klass::cast(class1)->name();
  2026   if (Klass::cast(class2)->oop_is_objArray()) {
  2027     class2 = objArrayKlass::cast(class2)->bottom_klass();
  2029   oop classloader2;
  2030   if (Klass::cast(class2)->oop_is_instance()) {
  2031     classloader2 = instanceKlass::cast(class2)->class_loader();
  2032   } else {
  2033     assert(Klass::cast(class2)->oop_is_typeArray(), "should be type array");
  2034     classloader2 = NULL;
  2036   Symbol* classname2 = Klass::cast(class2)->name();
  2038   return instanceKlass::is_same_class_package(classloader1, classname1,
  2039                                               classloader2, classname2);
  2042 bool instanceKlass::is_same_class_package(oop classloader2, Symbol* classname2) {
  2043   klassOop class1 = as_klassOop();
  2044   oop classloader1 = instanceKlass::cast(class1)->class_loader();
  2045   Symbol* classname1 = Klass::cast(class1)->name();
  2047   return instanceKlass::is_same_class_package(classloader1, classname1,
  2048                                               classloader2, classname2);
  2051 // return true if two classes are in the same package, classloader
  2052 // and classname information is enough to determine a class's package
  2053 bool instanceKlass::is_same_class_package(oop class_loader1, Symbol* class_name1,
  2054                                           oop class_loader2, Symbol* class_name2) {
  2055   if (class_loader1 != class_loader2) {
  2056     return false;
  2057   } else if (class_name1 == class_name2) {
  2058     return true;                // skip painful bytewise comparison
  2059   } else {
  2060     ResourceMark rm;
  2062     // The Symbol*'s are in UTF8 encoding. Since we only need to check explicitly
  2063     // for ASCII characters ('/', 'L', '['), we can keep them in UTF8 encoding.
  2064     // Otherwise, we just compare jbyte values between the strings.
  2065     const jbyte *name1 = class_name1->base();
  2066     const jbyte *name2 = class_name2->base();
  2068     const jbyte *last_slash1 = UTF8::strrchr(name1, class_name1->utf8_length(), '/');
  2069     const jbyte *last_slash2 = UTF8::strrchr(name2, class_name2->utf8_length(), '/');
  2071     if ((last_slash1 == NULL) || (last_slash2 == NULL)) {
  2072       // One of the two doesn't have a package.  Only return true
  2073       // if the other one also doesn't have a package.
  2074       return last_slash1 == last_slash2;
  2075     } else {
  2076       // Skip over '['s
  2077       if (*name1 == '[') {
  2078         do {
  2079           name1++;
  2080         } while (*name1 == '[');
  2081         if (*name1 != 'L') {
  2082           // Something is terribly wrong.  Shouldn't be here.
  2083           return false;
  2086       if (*name2 == '[') {
  2087         do {
  2088           name2++;
  2089         } while (*name2 == '[');
  2090         if (*name2 != 'L') {
  2091           // Something is terribly wrong.  Shouldn't be here.
  2092           return false;
  2096       // Check that package part is identical
  2097       int length1 = last_slash1 - name1;
  2098       int length2 = last_slash2 - name2;
  2100       return UTF8::equal(name1, length1, name2, length2);
  2105 // Returns true iff super_method can be overridden by a method in targetclassname
  2106 // See JSL 3rd edition 8.4.6.1
  2107 // Assumes name-signature match
  2108 // "this" is instanceKlass of super_method which must exist
  2109 // note that the instanceKlass of the method in the targetclassname has not always been created yet
  2110 bool instanceKlass::is_override(methodHandle super_method, Handle targetclassloader, Symbol* targetclassname, TRAPS) {
  2111    // Private methods can not be overridden
  2112    if (super_method->is_private()) {
  2113      return false;
  2115    // If super method is accessible, then override
  2116    if ((super_method->is_protected()) ||
  2117        (super_method->is_public())) {
  2118      return true;
  2120    // Package-private methods are not inherited outside of package
  2121    assert(super_method->is_package_private(), "must be package private");
  2122    return(is_same_class_package(targetclassloader(), targetclassname));
  2125 /* defined for now in jvm.cpp, for historical reasons *--
  2126 klassOop instanceKlass::compute_enclosing_class_impl(instanceKlassHandle self,
  2127                                                      Symbol*& simple_name_result, TRAPS) {
  2128   ...
  2130 */
  2132 // tell if two classes have the same enclosing class (at package level)
  2133 bool instanceKlass::is_same_package_member_impl(instanceKlassHandle class1,
  2134                                                 klassOop class2_oop, TRAPS) {
  2135   if (class2_oop == class1->as_klassOop())          return true;
  2136   if (!Klass::cast(class2_oop)->oop_is_instance())  return false;
  2137   instanceKlassHandle class2(THREAD, class2_oop);
  2139   // must be in same package before we try anything else
  2140   if (!class1->is_same_class_package(class2->class_loader(), class2->name()))
  2141     return false;
  2143   // As long as there is an outer1.getEnclosingClass,
  2144   // shift the search outward.
  2145   instanceKlassHandle outer1 = class1;
  2146   for (;;) {
  2147     // As we walk along, look for equalities between outer1 and class2.
  2148     // Eventually, the walks will terminate as outer1 stops
  2149     // at the top-level class around the original class.
  2150     bool ignore_inner_is_member;
  2151     klassOop next = outer1->compute_enclosing_class(&ignore_inner_is_member,
  2152                                                     CHECK_false);
  2153     if (next == NULL)  break;
  2154     if (next == class2())  return true;
  2155     outer1 = instanceKlassHandle(THREAD, next);
  2158   // Now do the same for class2.
  2159   instanceKlassHandle outer2 = class2;
  2160   for (;;) {
  2161     bool ignore_inner_is_member;
  2162     klassOop next = outer2->compute_enclosing_class(&ignore_inner_is_member,
  2163                                                     CHECK_false);
  2164     if (next == NULL)  break;
  2165     // Might as well check the new outer against all available values.
  2166     if (next == class1())  return true;
  2167     if (next == outer1())  return true;
  2168     outer2 = instanceKlassHandle(THREAD, next);
  2171   // If by this point we have not found an equality between the
  2172   // two classes, we know they are in separate package members.
  2173   return false;
  2177 jint instanceKlass::compute_modifier_flags(TRAPS) const {
  2178   klassOop k = as_klassOop();
  2179   jint access = access_flags().as_int();
  2181   // But check if it happens to be member class.
  2182   typeArrayOop inner_class_list = inner_classes();
  2183   int length = (inner_class_list == NULL) ? 0 : inner_class_list->length();
  2184   assert (length % instanceKlass::inner_class_next_offset == 0, "just checking");
  2185   if (length > 0) {
  2186     typeArrayHandle inner_class_list_h(THREAD, inner_class_list);
  2187     instanceKlassHandle ik(THREAD, k);
  2188     for (int i = 0; i < length; i += instanceKlass::inner_class_next_offset) {
  2189       int ioff = inner_class_list_h->ushort_at(
  2190                       i + instanceKlass::inner_class_inner_class_info_offset);
  2192       // Inner class attribute can be zero, skip it.
  2193       // Strange but true:  JVM spec. allows null inner class refs.
  2194       if (ioff == 0) continue;
  2196       // only look at classes that are already loaded
  2197       // since we are looking for the flags for our self.
  2198       Symbol* inner_name = ik->constants()->klass_name_at(ioff);
  2199       if ((ik->name() == inner_name)) {
  2200         // This is really a member class.
  2201         access = inner_class_list_h->ushort_at(i + instanceKlass::inner_class_access_flags_offset);
  2202         break;
  2206   // Remember to strip ACC_SUPER bit
  2207   return (access & (~JVM_ACC_SUPER)) & JVM_ACC_WRITTEN_FLAGS;
  2210 jint instanceKlass::jvmti_class_status() const {
  2211   jint result = 0;
  2213   if (is_linked()) {
  2214     result |= JVMTI_CLASS_STATUS_VERIFIED | JVMTI_CLASS_STATUS_PREPARED;
  2217   if (is_initialized()) {
  2218     assert(is_linked(), "Class status is not consistent");
  2219     result |= JVMTI_CLASS_STATUS_INITIALIZED;
  2221   if (is_in_error_state()) {
  2222     result |= JVMTI_CLASS_STATUS_ERROR;
  2224   return result;
  2227 methodOop instanceKlass::method_at_itable(klassOop holder, int index, TRAPS) {
  2228   itableOffsetEntry* ioe = (itableOffsetEntry*)start_of_itable();
  2229   int method_table_offset_in_words = ioe->offset()/wordSize;
  2230   int nof_interfaces = (method_table_offset_in_words - itable_offset_in_words())
  2231                        / itableOffsetEntry::size();
  2233   for (int cnt = 0 ; ; cnt ++, ioe ++) {
  2234     // If the interface isn't implemented by the receiver class,
  2235     // the VM should throw IncompatibleClassChangeError.
  2236     if (cnt >= nof_interfaces) {
  2237       THROW_0(vmSymbols::java_lang_IncompatibleClassChangeError());
  2240     klassOop ik = ioe->interface_klass();
  2241     if (ik == holder) break;
  2244   itableMethodEntry* ime = ioe->first_method_entry(as_klassOop());
  2245   methodOop m = ime[index].method();
  2246   if (m == NULL) {
  2247     THROW_0(vmSymbols::java_lang_AbstractMethodError());
  2249   return m;
  2252 // On-stack replacement stuff
  2253 void instanceKlass::add_osr_nmethod(nmethod* n) {
  2254   // only one compilation can be active
  2255   NEEDS_CLEANUP
  2256   // This is a short non-blocking critical region, so the no safepoint check is ok.
  2257   OsrList_lock->lock_without_safepoint_check();
  2258   assert(n->is_osr_method(), "wrong kind of nmethod");
  2259   n->set_osr_link(osr_nmethods_head());
  2260   set_osr_nmethods_head(n);
  2261   // Raise the highest osr level if necessary
  2262   if (TieredCompilation) {
  2263     methodOop m = n->method();
  2264     m->set_highest_osr_comp_level(MAX2(m->highest_osr_comp_level(), n->comp_level()));
  2266   // Remember to unlock again
  2267   OsrList_lock->unlock();
  2269   // Get rid of the osr methods for the same bci that have lower levels.
  2270   if (TieredCompilation) {
  2271     for (int l = CompLevel_limited_profile; l < n->comp_level(); l++) {
  2272       nmethod *inv = lookup_osr_nmethod(n->method(), n->osr_entry_bci(), l, true);
  2273       if (inv != NULL && inv->is_in_use()) {
  2274         inv->make_not_entrant();
  2281 void instanceKlass::remove_osr_nmethod(nmethod* n) {
  2282   // This is a short non-blocking critical region, so the no safepoint check is ok.
  2283   OsrList_lock->lock_without_safepoint_check();
  2284   assert(n->is_osr_method(), "wrong kind of nmethod");
  2285   nmethod* last = NULL;
  2286   nmethod* cur  = osr_nmethods_head();
  2287   int max_level = CompLevel_none;  // Find the max comp level excluding n
  2288   methodOop m = n->method();
  2289   // Search for match
  2290   while(cur != NULL && cur != n) {
  2291     if (TieredCompilation) {
  2292       // Find max level before n
  2293       max_level = MAX2(max_level, cur->comp_level());
  2295     last = cur;
  2296     cur = cur->osr_link();
  2298   nmethod* next = NULL;
  2299   if (cur == n) {
  2300     next = cur->osr_link();
  2301     if (last == NULL) {
  2302       // Remove first element
  2303       set_osr_nmethods_head(next);
  2304     } else {
  2305       last->set_osr_link(next);
  2308   n->set_osr_link(NULL);
  2309   if (TieredCompilation) {
  2310     cur = next;
  2311     while (cur != NULL) {
  2312       // Find max level after n
  2313       max_level = MAX2(max_level, cur->comp_level());
  2314       cur = cur->osr_link();
  2316     m->set_highest_osr_comp_level(max_level);
  2318   // Remember to unlock again
  2319   OsrList_lock->unlock();
  2322 nmethod* instanceKlass::lookup_osr_nmethod(const methodOop m, int bci, int comp_level, bool match_level) const {
  2323   // This is a short non-blocking critical region, so the no safepoint check is ok.
  2324   OsrList_lock->lock_without_safepoint_check();
  2325   nmethod* osr = osr_nmethods_head();
  2326   nmethod* best = NULL;
  2327   while (osr != NULL) {
  2328     assert(osr->is_osr_method(), "wrong kind of nmethod found in chain");
  2329     // There can be a time when a c1 osr method exists but we are waiting
  2330     // for a c2 version. When c2 completes its osr nmethod we will trash
  2331     // the c1 version and only be able to find the c2 version. However
  2332     // while we overflow in the c1 code at back branches we don't want to
  2333     // try and switch to the same code as we are already running
  2335     if (osr->method() == m &&
  2336         (bci == InvocationEntryBci || osr->osr_entry_bci() == bci)) {
  2337       if (match_level) {
  2338         if (osr->comp_level() == comp_level) {
  2339           // Found a match - return it.
  2340           OsrList_lock->unlock();
  2341           return osr;
  2343       } else {
  2344         if (best == NULL || (osr->comp_level() > best->comp_level())) {
  2345           if (osr->comp_level() == CompLevel_highest_tier) {
  2346             // Found the best possible - return it.
  2347             OsrList_lock->unlock();
  2348             return osr;
  2350           best = osr;
  2354     osr = osr->osr_link();
  2356   OsrList_lock->unlock();
  2357   if (best != NULL && best->comp_level() >= comp_level && match_level == false) {
  2358     return best;
  2360   return NULL;
  2363 // -----------------------------------------------------------------------------------------------------
  2364 #ifndef PRODUCT
  2366 // Printing
  2368 #define BULLET  " - "
  2370 void FieldPrinter::do_field(fieldDescriptor* fd) {
  2371   _st->print(BULLET);
  2372    if (fd->is_static() || (_obj == NULL)) {
  2373      fd->print_on(_st);
  2374      _st->cr();
  2375    } else {
  2376      fd->print_on_for(_st, _obj);
  2377      _st->cr();
  2382 void instanceKlass::oop_print_on(oop obj, outputStream* st) {
  2383   Klass::oop_print_on(obj, st);
  2385   if (as_klassOop() == SystemDictionary::String_klass()) {
  2386     typeArrayOop value  = java_lang_String::value(obj);
  2387     juint        offset = java_lang_String::offset(obj);
  2388     juint        length = java_lang_String::length(obj);
  2389     if (value != NULL &&
  2390         value->is_typeArray() &&
  2391         offset          <= (juint) value->length() &&
  2392         offset + length <= (juint) value->length()) {
  2393       st->print(BULLET"string: ");
  2394       Handle h_obj(obj);
  2395       java_lang_String::print(h_obj, st);
  2396       st->cr();
  2397       if (!WizardMode)  return;  // that is enough
  2401   st->print_cr(BULLET"---- fields (total size %d words):", oop_size(obj));
  2402   FieldPrinter print_nonstatic_field(st, obj);
  2403   do_nonstatic_fields(&print_nonstatic_field);
  2405   if (as_klassOop() == SystemDictionary::Class_klass()) {
  2406     st->print(BULLET"signature: ");
  2407     java_lang_Class::print_signature(obj, st);
  2408     st->cr();
  2409     klassOop mirrored_klass = java_lang_Class::as_klassOop(obj);
  2410     st->print(BULLET"fake entry for mirror: ");
  2411     mirrored_klass->print_value_on(st);
  2412     st->cr();
  2413     st->print(BULLET"fake entry resolved_constructor: ");
  2414     methodOop ctor = java_lang_Class::resolved_constructor(obj);
  2415     ctor->print_value_on(st);
  2416     klassOop array_klass = java_lang_Class::array_klass(obj);
  2417     st->cr();
  2418     st->print(BULLET"fake entry for array: ");
  2419     array_klass->print_value_on(st);
  2420     st->cr();
  2421   } else if (as_klassOop() == SystemDictionary::MethodType_klass()) {
  2422     st->print(BULLET"signature: ");
  2423     java_dyn_MethodType::print_signature(obj, st);
  2424     st->cr();
  2428 #endif //PRODUCT
  2430 void instanceKlass::oop_print_value_on(oop obj, outputStream* st) {
  2431   st->print("a ");
  2432   name()->print_value_on(st);
  2433   obj->print_address_on(st);
  2434   if (as_klassOop() == SystemDictionary::String_klass()
  2435       && java_lang_String::value(obj) != NULL) {
  2436     ResourceMark rm;
  2437     int len = java_lang_String::length(obj);
  2438     int plen = (len < 24 ? len : 12);
  2439     char* str = java_lang_String::as_utf8_string(obj, 0, plen);
  2440     st->print(" = \"%s\"", str);
  2441     if (len > plen)
  2442       st->print("...[%d]", len);
  2443   } else if (as_klassOop() == SystemDictionary::Class_klass()) {
  2444     klassOop k = java_lang_Class::as_klassOop(obj);
  2445     st->print(" = ");
  2446     if (k != NULL) {
  2447       k->print_value_on(st);
  2448     } else {
  2449       const char* tname = type2name(java_lang_Class::primitive_type(obj));
  2450       st->print("%s", tname ? tname : "type?");
  2452   } else if (as_klassOop() == SystemDictionary::MethodType_klass()) {
  2453     st->print(" = ");
  2454     java_dyn_MethodType::print_signature(obj, st);
  2455   } else if (java_lang_boxing_object::is_instance(obj)) {
  2456     st->print(" = ");
  2457     java_lang_boxing_object::print(obj, st);
  2461 const char* instanceKlass::internal_name() const {
  2462   return external_name();
  2465 // Verification
  2467 class VerifyFieldClosure: public OopClosure {
  2468  protected:
  2469   template <class T> void do_oop_work(T* p) {
  2470     guarantee(Universe::heap()->is_in_closed_subset(p), "should be in heap");
  2471     oop obj = oopDesc::load_decode_heap_oop(p);
  2472     if (!obj->is_oop_or_null()) {
  2473       tty->print_cr("Failed: " PTR_FORMAT " -> " PTR_FORMAT, p, (address)obj);
  2474       Universe::print();
  2475       guarantee(false, "boom");
  2478  public:
  2479   virtual void do_oop(oop* p)       { VerifyFieldClosure::do_oop_work(p); }
  2480   virtual void do_oop(narrowOop* p) { VerifyFieldClosure::do_oop_work(p); }
  2481 };
  2483 void instanceKlass::oop_verify_on(oop obj, outputStream* st) {
  2484   Klass::oop_verify_on(obj, st);
  2485   VerifyFieldClosure blk;
  2486   oop_oop_iterate(obj, &blk);
  2489 #ifndef PRODUCT
  2491 void instanceKlass::verify_class_klass_nonstatic_oop_maps(klassOop k) {
  2492   // This verification code is disabled.  JDK_Version::is_gte_jdk14x_version()
  2493   // cannot be called since this function is called before the VM is
  2494   // able to determine what JDK version is running with.
  2495   // The check below always is false since 1.4.
  2496   return;
  2498   // This verification code temporarily disabled for the 1.4
  2499   // reflection implementation since java.lang.Class now has
  2500   // Java-level instance fields. Should rewrite this to handle this
  2501   // case.
  2502   if (!(JDK_Version::is_gte_jdk14x_version() && UseNewReflection)) {
  2503     // Verify that java.lang.Class instances have a fake oop field added.
  2504     instanceKlass* ik = instanceKlass::cast(k);
  2506     // Check that we have the right class
  2507     static bool first_time = true;
  2508     guarantee(k == SystemDictionary::Class_klass() && first_time, "Invalid verify of maps");
  2509     first_time = false;
  2510     const int extra = java_lang_Class::number_of_fake_oop_fields;
  2511     guarantee(ik->nonstatic_field_size() == extra, "just checking");
  2512     guarantee(ik->nonstatic_oop_map_count() == 1, "just checking");
  2513     guarantee(ik->size_helper() == align_object_size(instanceOopDesc::header_size() + extra), "just checking");
  2515     // Check that the map is (2,extra)
  2516     int offset = java_lang_Class::klass_offset;
  2518     OopMapBlock* map = ik->start_of_nonstatic_oop_maps();
  2519     guarantee(map->offset() == offset && map->count() == (unsigned int) extra,
  2520               "sanity");
  2524 #endif // ndef PRODUCT
  2526 // JNIid class for jfieldIDs only
  2527 // Note to reviewers:
  2528 // These JNI functions are just moved over to column 1 and not changed
  2529 // in the compressed oops workspace.
  2530 JNIid::JNIid(klassOop holder, int offset, JNIid* next) {
  2531   _holder = holder;
  2532   _offset = offset;
  2533   _next = next;
  2534   debug_only(_is_static_field_id = false;)
  2538 JNIid* JNIid::find(int offset) {
  2539   JNIid* current = this;
  2540   while (current != NULL) {
  2541     if (current->offset() == offset) return current;
  2542     current = current->next();
  2544   return NULL;
  2547 void JNIid::oops_do(OopClosure* f) {
  2548   for (JNIid* cur = this; cur != NULL; cur = cur->next()) {
  2549     f->do_oop(cur->holder_addr());
  2553 void JNIid::deallocate(JNIid* current) {
  2554   while (current != NULL) {
  2555     JNIid* next = current->next();
  2556     delete current;
  2557     current = next;
  2562 void JNIid::verify(klassOop holder) {
  2563   int first_field_offset  = instanceKlass::cast(holder)->offset_of_static_fields();
  2564   int end_field_offset;
  2565   end_field_offset = first_field_offset + (instanceKlass::cast(holder)->static_field_size() * wordSize);
  2567   JNIid* current = this;
  2568   while (current != NULL) {
  2569     guarantee(current->holder() == holder, "Invalid klass in JNIid");
  2570 #ifdef ASSERT
  2571     int o = current->offset();
  2572     if (current->is_static_field_id()) {
  2573       guarantee(o >= first_field_offset  && o < end_field_offset,  "Invalid static field offset in JNIid");
  2575 #endif
  2576     current = current->next();
  2581 #ifdef ASSERT
  2582 void instanceKlass::set_init_state(ClassState state) {
  2583   bool good_state = as_klassOop()->is_shared() ? (_init_state <= state)
  2584                                                : (_init_state < state);
  2585   assert(good_state || state == allocated, "illegal state transition");
  2586   _init_state = state;
  2588 #endif
  2591 // RedefineClasses() support for previous versions:
  2593 // Add an information node that contains weak references to the
  2594 // interesting parts of the previous version of the_class.
  2595 // This is also where we clean out any unused weak references.
  2596 // Note that while we delete nodes from the _previous_versions
  2597 // array, we never delete the array itself until the klass is
  2598 // unloaded. The has_been_redefined() query depends on that fact.
  2599 //
  2600 void instanceKlass::add_previous_version(instanceKlassHandle ikh,
  2601        BitMap* emcp_methods, int emcp_method_count) {
  2602   assert(Thread::current()->is_VM_thread(),
  2603          "only VMThread can add previous versions");
  2605   if (_previous_versions == NULL) {
  2606     // This is the first previous version so make some space.
  2607     // Start with 2 elements under the assumption that the class
  2608     // won't be redefined much.
  2609     _previous_versions =  new (ResourceObj::C_HEAP)
  2610                             GrowableArray<PreviousVersionNode *>(2, true);
  2613   // RC_TRACE macro has an embedded ResourceMark
  2614   RC_TRACE(0x00000100, ("adding previous version ref for %s @%d, EMCP_cnt=%d",
  2615     ikh->external_name(), _previous_versions->length(), emcp_method_count));
  2616   constantPoolHandle cp_h(ikh->constants());
  2617   jobject cp_ref;
  2618   if (cp_h->is_shared()) {
  2619     // a shared ConstantPool requires a regular reference; a weak
  2620     // reference would be collectible
  2621     cp_ref = JNIHandles::make_global(cp_h);
  2622   } else {
  2623     cp_ref = JNIHandles::make_weak_global(cp_h);
  2625   PreviousVersionNode * pv_node = NULL;
  2626   objArrayOop old_methods = ikh->methods();
  2628   if (emcp_method_count == 0) {
  2629     // non-shared ConstantPool gets a weak reference
  2630     pv_node = new PreviousVersionNode(cp_ref, !cp_h->is_shared(), NULL);
  2631     RC_TRACE(0x00000400,
  2632       ("add: all methods are obsolete; flushing any EMCP weak refs"));
  2633   } else {
  2634     int local_count = 0;
  2635     GrowableArray<jweak>* method_refs = new (ResourceObj::C_HEAP)
  2636       GrowableArray<jweak>(emcp_method_count, true);
  2637     for (int i = 0; i < old_methods->length(); i++) {
  2638       if (emcp_methods->at(i)) {
  2639         // this old method is EMCP so save a weak ref
  2640         methodOop old_method = (methodOop) old_methods->obj_at(i);
  2641         methodHandle old_method_h(old_method);
  2642         jweak method_ref = JNIHandles::make_weak_global(old_method_h);
  2643         method_refs->append(method_ref);
  2644         if (++local_count >= emcp_method_count) {
  2645           // no more EMCP methods so bail out now
  2646           break;
  2650     // non-shared ConstantPool gets a weak reference
  2651     pv_node = new PreviousVersionNode(cp_ref, !cp_h->is_shared(), method_refs);
  2654   _previous_versions->append(pv_node);
  2656   // Using weak references allows the interesting parts of previous
  2657   // classes to be GC'ed when they are no longer needed. Since the
  2658   // caller is the VMThread and we are at a safepoint, this is a good
  2659   // time to clear out unused weak references.
  2661   RC_TRACE(0x00000400, ("add: previous version length=%d",
  2662     _previous_versions->length()));
  2664   // skip the last entry since we just added it
  2665   for (int i = _previous_versions->length() - 2; i >= 0; i--) {
  2666     // check the previous versions array for a GC'ed weak refs
  2667     pv_node = _previous_versions->at(i);
  2668     cp_ref = pv_node->prev_constant_pool();
  2669     assert(cp_ref != NULL, "cp ref was unexpectedly cleared");
  2670     if (cp_ref == NULL) {
  2671       delete pv_node;
  2672       _previous_versions->remove_at(i);
  2673       // Since we are traversing the array backwards, we don't have to
  2674       // do anything special with the index.
  2675       continue;  // robustness
  2678     constantPoolOop cp = (constantPoolOop)JNIHandles::resolve(cp_ref);
  2679     if (cp == NULL) {
  2680       // this entry has been GC'ed so remove it
  2681       delete pv_node;
  2682       _previous_versions->remove_at(i);
  2683       // Since we are traversing the array backwards, we don't have to
  2684       // do anything special with the index.
  2685       continue;
  2686     } else {
  2687       RC_TRACE(0x00000400, ("add: previous version @%d is alive", i));
  2690     GrowableArray<jweak>* method_refs = pv_node->prev_EMCP_methods();
  2691     if (method_refs != NULL) {
  2692       RC_TRACE(0x00000400, ("add: previous methods length=%d",
  2693         method_refs->length()));
  2694       for (int j = method_refs->length() - 1; j >= 0; j--) {
  2695         jweak method_ref = method_refs->at(j);
  2696         assert(method_ref != NULL, "weak method ref was unexpectedly cleared");
  2697         if (method_ref == NULL) {
  2698           method_refs->remove_at(j);
  2699           // Since we are traversing the array backwards, we don't have to
  2700           // do anything special with the index.
  2701           continue;  // robustness
  2704         methodOop method = (methodOop)JNIHandles::resolve(method_ref);
  2705         if (method == NULL || emcp_method_count == 0) {
  2706           // This method entry has been GC'ed or the current
  2707           // RedefineClasses() call has made all methods obsolete
  2708           // so remove it.
  2709           JNIHandles::destroy_weak_global(method_ref);
  2710           method_refs->remove_at(j);
  2711         } else {
  2712           // RC_TRACE macro has an embedded ResourceMark
  2713           RC_TRACE(0x00000400,
  2714             ("add: %s(%s): previous method @%d in version @%d is alive",
  2715             method->name()->as_C_string(), method->signature()->as_C_string(),
  2716             j, i));
  2722   int obsolete_method_count = old_methods->length() - emcp_method_count;
  2724   if (emcp_method_count != 0 && obsolete_method_count != 0 &&
  2725       _previous_versions->length() > 1) {
  2726     // We have a mix of obsolete and EMCP methods. If there is more
  2727     // than the previous version that we just added, then we have to
  2728     // clear out any matching EMCP method entries the hard way.
  2729     int local_count = 0;
  2730     for (int i = 0; i < old_methods->length(); i++) {
  2731       if (!emcp_methods->at(i)) {
  2732         // only obsolete methods are interesting
  2733         methodOop old_method = (methodOop) old_methods->obj_at(i);
  2734         Symbol* m_name = old_method->name();
  2735         Symbol* m_signature = old_method->signature();
  2737         // skip the last entry since we just added it
  2738         for (int j = _previous_versions->length() - 2; j >= 0; j--) {
  2739           // check the previous versions array for a GC'ed weak refs
  2740           pv_node = _previous_versions->at(j);
  2741           cp_ref = pv_node->prev_constant_pool();
  2742           assert(cp_ref != NULL, "cp ref was unexpectedly cleared");
  2743           if (cp_ref == NULL) {
  2744             delete pv_node;
  2745             _previous_versions->remove_at(j);
  2746             // Since we are traversing the array backwards, we don't have to
  2747             // do anything special with the index.
  2748             continue;  // robustness
  2751           constantPoolOop cp = (constantPoolOop)JNIHandles::resolve(cp_ref);
  2752           if (cp == NULL) {
  2753             // this entry has been GC'ed so remove it
  2754             delete pv_node;
  2755             _previous_versions->remove_at(j);
  2756             // Since we are traversing the array backwards, we don't have to
  2757             // do anything special with the index.
  2758             continue;
  2761           GrowableArray<jweak>* method_refs = pv_node->prev_EMCP_methods();
  2762           if (method_refs == NULL) {
  2763             // We have run into a PreviousVersion generation where
  2764             // all methods were made obsolete during that generation's
  2765             // RedefineClasses() operation. At the time of that
  2766             // operation, all EMCP methods were flushed so we don't
  2767             // have to go back any further.
  2768             //
  2769             // A NULL method_refs is different than an empty method_refs.
  2770             // We cannot infer any optimizations about older generations
  2771             // from an empty method_refs for the current generation.
  2772             break;
  2775           for (int k = method_refs->length() - 1; k >= 0; k--) {
  2776             jweak method_ref = method_refs->at(k);
  2777             assert(method_ref != NULL,
  2778               "weak method ref was unexpectedly cleared");
  2779             if (method_ref == NULL) {
  2780               method_refs->remove_at(k);
  2781               // Since we are traversing the array backwards, we don't
  2782               // have to do anything special with the index.
  2783               continue;  // robustness
  2786             methodOop method = (methodOop)JNIHandles::resolve(method_ref);
  2787             if (method == NULL) {
  2788               // this method entry has been GC'ed so skip it
  2789               JNIHandles::destroy_weak_global(method_ref);
  2790               method_refs->remove_at(k);
  2791               continue;
  2794             if (method->name() == m_name &&
  2795                 method->signature() == m_signature) {
  2796               // The current RedefineClasses() call has made all EMCP
  2797               // versions of this method obsolete so mark it as obsolete
  2798               // and remove the weak ref.
  2799               RC_TRACE(0x00000400,
  2800                 ("add: %s(%s): flush obsolete method @%d in version @%d",
  2801                 m_name->as_C_string(), m_signature->as_C_string(), k, j));
  2803               method->set_is_obsolete();
  2804               JNIHandles::destroy_weak_global(method_ref);
  2805               method_refs->remove_at(k);
  2806               break;
  2810           // The previous loop may not find a matching EMCP method, but
  2811           // that doesn't mean that we can optimize and not go any
  2812           // further back in the PreviousVersion generations. The EMCP
  2813           // method for this generation could have already been GC'ed,
  2814           // but there still may be an older EMCP method that has not
  2815           // been GC'ed.
  2818         if (++local_count >= obsolete_method_count) {
  2819           // no more obsolete methods so bail out now
  2820           break;
  2825 } // end add_previous_version()
  2828 // Determine if instanceKlass has a previous version.
  2829 bool instanceKlass::has_previous_version() const {
  2830   if (_previous_versions == NULL) {
  2831     // no previous versions array so answer is easy
  2832     return false;
  2835   for (int i = _previous_versions->length() - 1; i >= 0; i--) {
  2836     // Check the previous versions array for an info node that hasn't
  2837     // been GC'ed
  2838     PreviousVersionNode * pv_node = _previous_versions->at(i);
  2840     jobject cp_ref = pv_node->prev_constant_pool();
  2841     assert(cp_ref != NULL, "cp reference was unexpectedly cleared");
  2842     if (cp_ref == NULL) {
  2843       continue;  // robustness
  2846     constantPoolOop cp = (constantPoolOop)JNIHandles::resolve(cp_ref);
  2847     if (cp != NULL) {
  2848       // we have at least one previous version
  2849       return true;
  2852     // We don't have to check the method refs. If the constant pool has
  2853     // been GC'ed then so have the methods.
  2856   // all of the underlying nodes' info has been GC'ed
  2857   return false;
  2858 } // end has_previous_version()
  2860 methodOop instanceKlass::method_with_idnum(int idnum) {
  2861   methodOop m = NULL;
  2862   if (idnum < methods()->length()) {
  2863     m = (methodOop) methods()->obj_at(idnum);
  2865   if (m == NULL || m->method_idnum() != idnum) {
  2866     for (int index = 0; index < methods()->length(); ++index) {
  2867       m = (methodOop) methods()->obj_at(index);
  2868       if (m->method_idnum() == idnum) {
  2869         return m;
  2873   return m;
  2877 // Set the annotation at 'idnum' to 'anno'.
  2878 // We don't want to create or extend the array if 'anno' is NULL, since that is the
  2879 // default value.  However, if the array exists and is long enough, we must set NULL values.
  2880 void instanceKlass::set_methods_annotations_of(int idnum, typeArrayOop anno, objArrayOop* md_p) {
  2881   objArrayOop md = *md_p;
  2882   if (md != NULL && md->length() > idnum) {
  2883     md->obj_at_put(idnum, anno);
  2884   } else if (anno != NULL) {
  2885     // create the array
  2886     int length = MAX2(idnum+1, (int)_idnum_allocated_count);
  2887     md = oopFactory::new_system_objArray(length, Thread::current());
  2888     if (*md_p != NULL) {
  2889       // copy the existing entries
  2890       for (int index = 0; index < (*md_p)->length(); index++) {
  2891         md->obj_at_put(index, (*md_p)->obj_at(index));
  2894     set_annotations(md, md_p);
  2895     md->obj_at_put(idnum, anno);
  2896   } // if no array and idnum isn't included there is nothing to do
  2899 // Construct a PreviousVersionNode entry for the array hung off
  2900 // the instanceKlass.
  2901 PreviousVersionNode::PreviousVersionNode(jobject prev_constant_pool,
  2902   bool prev_cp_is_weak, GrowableArray<jweak>* prev_EMCP_methods) {
  2904   _prev_constant_pool = prev_constant_pool;
  2905   _prev_cp_is_weak = prev_cp_is_weak;
  2906   _prev_EMCP_methods = prev_EMCP_methods;
  2910 // Destroy a PreviousVersionNode
  2911 PreviousVersionNode::~PreviousVersionNode() {
  2912   if (_prev_constant_pool != NULL) {
  2913     if (_prev_cp_is_weak) {
  2914       JNIHandles::destroy_weak_global(_prev_constant_pool);
  2915     } else {
  2916       JNIHandles::destroy_global(_prev_constant_pool);
  2920   if (_prev_EMCP_methods != NULL) {
  2921     for (int i = _prev_EMCP_methods->length() - 1; i >= 0; i--) {
  2922       jweak method_ref = _prev_EMCP_methods->at(i);
  2923       if (method_ref != NULL) {
  2924         JNIHandles::destroy_weak_global(method_ref);
  2927     delete _prev_EMCP_methods;
  2932 // Construct a PreviousVersionInfo entry
  2933 PreviousVersionInfo::PreviousVersionInfo(PreviousVersionNode *pv_node) {
  2934   _prev_constant_pool_handle = constantPoolHandle();  // NULL handle
  2935   _prev_EMCP_method_handles = NULL;
  2937   jobject cp_ref = pv_node->prev_constant_pool();
  2938   assert(cp_ref != NULL, "constant pool ref was unexpectedly cleared");
  2939   if (cp_ref == NULL) {
  2940     return;  // robustness
  2943   constantPoolOop cp = (constantPoolOop)JNIHandles::resolve(cp_ref);
  2944   if (cp == NULL) {
  2945     // Weak reference has been GC'ed. Since the constant pool has been
  2946     // GC'ed, the methods have also been GC'ed.
  2947     return;
  2950   // make the constantPoolOop safe to return
  2951   _prev_constant_pool_handle = constantPoolHandle(cp);
  2953   GrowableArray<jweak>* method_refs = pv_node->prev_EMCP_methods();
  2954   if (method_refs == NULL) {
  2955     // the instanceKlass did not have any EMCP methods
  2956     return;
  2959   _prev_EMCP_method_handles = new GrowableArray<methodHandle>(10);
  2961   int n_methods = method_refs->length();
  2962   for (int i = 0; i < n_methods; i++) {
  2963     jweak method_ref = method_refs->at(i);
  2964     assert(method_ref != NULL, "weak method ref was unexpectedly cleared");
  2965     if (method_ref == NULL) {
  2966       continue;  // robustness
  2969     methodOop method = (methodOop)JNIHandles::resolve(method_ref);
  2970     if (method == NULL) {
  2971       // this entry has been GC'ed so skip it
  2972       continue;
  2975     // make the methodOop safe to return
  2976     _prev_EMCP_method_handles->append(methodHandle(method));
  2981 // Destroy a PreviousVersionInfo
  2982 PreviousVersionInfo::~PreviousVersionInfo() {
  2983   // Since _prev_EMCP_method_handles is not C-heap allocated, we
  2984   // don't have to delete it.
  2988 // Construct a helper for walking the previous versions array
  2989 PreviousVersionWalker::PreviousVersionWalker(instanceKlass *ik) {
  2990   _previous_versions = ik->previous_versions();
  2991   _current_index = 0;
  2992   // _hm needs no initialization
  2993   _current_p = NULL;
  2997 // Destroy a PreviousVersionWalker
  2998 PreviousVersionWalker::~PreviousVersionWalker() {
  2999   // Delete the current info just in case the caller didn't walk to
  3000   // the end of the previous versions list. No harm if _current_p is
  3001   // already NULL.
  3002   delete _current_p;
  3004   // When _hm is destroyed, all the Handles returned in
  3005   // PreviousVersionInfo objects will be destroyed.
  3006   // Also, after this destructor is finished it will be
  3007   // safe to delete the GrowableArray allocated in the
  3008   // PreviousVersionInfo objects.
  3012 // Return the interesting information for the next previous version
  3013 // of the klass. Returns NULL if there are no more previous versions.
  3014 PreviousVersionInfo* PreviousVersionWalker::next_previous_version() {
  3015   if (_previous_versions == NULL) {
  3016     // no previous versions so nothing to return
  3017     return NULL;
  3020   delete _current_p;  // cleanup the previous info for the caller
  3021   _current_p = NULL;  // reset to NULL so we don't delete same object twice
  3023   int length = _previous_versions->length();
  3025   while (_current_index < length) {
  3026     PreviousVersionNode * pv_node = _previous_versions->at(_current_index++);
  3027     PreviousVersionInfo * pv_info = new (ResourceObj::C_HEAP)
  3028                                           PreviousVersionInfo(pv_node);
  3030     constantPoolHandle cp_h = pv_info->prev_constant_pool_handle();
  3031     if (cp_h.is_null()) {
  3032       delete pv_info;
  3034       // The underlying node's info has been GC'ed so try the next one.
  3035       // We don't have to check the methods. If the constant pool has
  3036       // GC'ed then so have the methods.
  3037       continue;
  3040     // Found a node with non GC'ed info so return it. The caller will
  3041     // need to delete pv_info when they are done with it.
  3042     _current_p = pv_info;
  3043     return pv_info;
  3046   // all of the underlying nodes' info has been GC'ed
  3047   return NULL;
  3048 } // end next_previous_version()

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