src/share/vm/oops/instanceKlass.cpp

Wed, 02 Jan 2013 20:28:09 -0500

author
coleenp
date
Wed, 02 Jan 2013 20:28:09 -0500
changeset 4395
cc6a617fffd2
parent 4393
35431a769282
child 4401
37a3e8b7a1e9
permissions
-rw-r--r--

8005494: SIGSEGV in Rewriter::relocate_and_link() when testing Weblogic with CompressedOops and KlassPtrs
Summary: Relocate functions with jsr's when rewriting so not repeated after reading shared archive
Reviewed-by: twisti, jrose

     1 /*
     2  * Copyright (c) 1997, 2012, 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/metadataFactory.hpp"
    38 #include "memory/oopFactory.hpp"
    39 #include "oops/fieldStreams.hpp"
    40 #include "oops/instanceClassLoaderKlass.hpp"
    41 #include "oops/instanceKlass.hpp"
    42 #include "oops/instanceMirrorKlass.hpp"
    43 #include "oops/instanceOop.hpp"
    44 #include "oops/klass.inline.hpp"
    45 #include "oops/method.hpp"
    46 #include "oops/oop.inline.hpp"
    47 #include "oops/symbol.hpp"
    48 #include "prims/jvmtiExport.hpp"
    49 #include "prims/jvmtiRedefineClassesTrace.hpp"
    50 #include "prims/methodComparator.hpp"
    51 #include "runtime/fieldDescriptor.hpp"
    52 #include "runtime/handles.inline.hpp"
    53 #include "runtime/javaCalls.hpp"
    54 #include "runtime/mutexLocker.hpp"
    55 #include "runtime/thread.inline.hpp"
    56 #include "services/threadService.hpp"
    57 #include "utilities/dtrace.hpp"
    58 #ifndef SERIALGC
    59 #include "gc_implementation/concurrentMarkSweep/cmsOopClosures.inline.hpp"
    60 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
    61 #include "gc_implementation/g1/g1OopClosures.inline.hpp"
    62 #include "gc_implementation/g1/g1RemSet.inline.hpp"
    63 #include "gc_implementation/g1/heapRegionSeq.inline.hpp"
    64 #include "gc_implementation/parNew/parOopClosures.inline.hpp"
    65 #include "gc_implementation/parallelScavenge/parallelScavengeHeap.inline.hpp"
    66 #include "gc_implementation/parallelScavenge/psPromotionManager.inline.hpp"
    67 #include "gc_implementation/parallelScavenge/psScavenge.inline.hpp"
    68 #include "oops/oop.pcgc.inline.hpp"
    69 #endif
    70 #ifdef COMPILER1
    71 #include "c1/c1_Compiler.hpp"
    72 #endif
    74 #ifdef DTRACE_ENABLED
    76 #ifndef USDT2
    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   }
   120 #else /* USDT2 */
   122 #define HOTSPOT_CLASS_INITIALIZATION_required HOTSPOT_CLASS_INITIALIZATION_REQUIRED
   123 #define HOTSPOT_CLASS_INITIALIZATION_recursive HOTSPOT_CLASS_INITIALIZATION_RECURSIVE
   124 #define HOTSPOT_CLASS_INITIALIZATION_concurrent HOTSPOT_CLASS_INITIALIZATION_CONCURRENT
   125 #define HOTSPOT_CLASS_INITIALIZATION_erroneous HOTSPOT_CLASS_INITIALIZATION_ERRONEOUS
   126 #define HOTSPOT_CLASS_INITIALIZATION_super__failed HOTSPOT_CLASS_INITIALIZATION_SUPER_FAILED
   127 #define HOTSPOT_CLASS_INITIALIZATION_clinit HOTSPOT_CLASS_INITIALIZATION_CLINIT
   128 #define HOTSPOT_CLASS_INITIALIZATION_error HOTSPOT_CLASS_INITIALIZATION_ERROR
   129 #define HOTSPOT_CLASS_INITIALIZATION_end HOTSPOT_CLASS_INITIALIZATION_END
   130 #define DTRACE_CLASSINIT_PROBE(type, clss, thread_type)          \
   131   {                                                              \
   132     char* data = NULL;                                           \
   133     int len = 0;                                                 \
   134     Symbol* name = (clss)->name();                               \
   135     if (name != NULL) {                                          \
   136       data = (char*)name->bytes();                               \
   137       len = name->utf8_length();                                 \
   138     }                                                            \
   139     HOTSPOT_CLASS_INITIALIZATION_##type(                         \
   140       data, len, (clss)->class_loader(), thread_type);           \
   141   }
   143 #define DTRACE_CLASSINIT_PROBE_WAIT(type, clss, thread_type, wait) \
   144   {                                                              \
   145     char* data = NULL;                                           \
   146     int len = 0;                                                 \
   147     Symbol* name = (clss)->name();                               \
   148     if (name != NULL) {                                          \
   149       data = (char*)name->bytes();                               \
   150       len = name->utf8_length();                                 \
   151     }                                                            \
   152     HOTSPOT_CLASS_INITIALIZATION_##type(                         \
   153       data, len, (clss)->class_loader(), thread_type, wait);     \
   154   }
   155 #endif /* USDT2 */
   157 #else //  ndef DTRACE_ENABLED
   159 #define DTRACE_CLASSINIT_PROBE(type, clss, thread_type)
   160 #define DTRACE_CLASSINIT_PROBE_WAIT(type, clss, thread_type, wait)
   162 #endif //  ndef DTRACE_ENABLED
   164 Klass* InstanceKlass::allocate_instance_klass(ClassLoaderData* loader_data,
   165                                                 int vtable_len,
   166                                                 int itable_len,
   167                                                 int static_field_size,
   168                                                 int nonstatic_oop_map_size,
   169                                                 ReferenceType rt,
   170                                                 AccessFlags access_flags,
   171                                                 Symbol* name,
   172                                               Klass* super_klass,
   173                                                 KlassHandle host_klass,
   174                                                 TRAPS) {
   176   int size = InstanceKlass::size(vtable_len, itable_len, nonstatic_oop_map_size,
   177                                  access_flags.is_interface(),
   178                                  !host_klass.is_null());
   180   // Allocation
   181   InstanceKlass* ik;
   182   if (rt == REF_NONE) {
   183     if (name == vmSymbols::java_lang_Class()) {
   184       ik = new (loader_data, size, THREAD) InstanceMirrorKlass(
   185         vtable_len, itable_len, static_field_size, nonstatic_oop_map_size, rt,
   186         access_flags, !host_klass.is_null());
   187     } else if (name == vmSymbols::java_lang_ClassLoader() ||
   188           (SystemDictionary::ClassLoader_klass_loaded() &&
   189           super_klass != NULL &&
   190           super_klass->is_subtype_of(SystemDictionary::ClassLoader_klass()))) {
   191       ik = new (loader_data, size, THREAD) InstanceClassLoaderKlass(
   192         vtable_len, itable_len, static_field_size, nonstatic_oop_map_size, rt,
   193         access_flags, !host_klass.is_null());
   194     } else {
   195       // normal class
   196       ik = new (loader_data, size, THREAD) InstanceKlass(
   197         vtable_len, itable_len, static_field_size, nonstatic_oop_map_size, rt,
   198         access_flags, !host_klass.is_null());
   199     }
   200   } else {
   201     // reference klass
   202     ik = new (loader_data, size, THREAD) InstanceRefKlass(
   203         vtable_len, itable_len, static_field_size, nonstatic_oop_map_size, rt,
   204         access_flags, !host_klass.is_null());
   205   }
   207   return ik;
   208 }
   210 InstanceKlass::InstanceKlass(int vtable_len,
   211                              int itable_len,
   212                              int static_field_size,
   213                              int nonstatic_oop_map_size,
   214                              ReferenceType rt,
   215                              AccessFlags access_flags,
   216                              bool is_anonymous) {
   217   No_Safepoint_Verifier no_safepoint; // until k becomes parsable
   219   int size = InstanceKlass::size(vtable_len, itable_len, nonstatic_oop_map_size,
   220                                  access_flags.is_interface(), is_anonymous);
   222   // The sizes of these these three variables are used for determining the
   223   // size of the instanceKlassOop. It is critical that these are set to the right
   224   // sizes before the first GC, i.e., when we allocate the mirror.
   225   this->set_vtable_length(vtable_len);
   226   this->set_itable_length(itable_len);
   227   this->set_static_field_size(static_field_size);
   228   this->set_nonstatic_oop_map_size(nonstatic_oop_map_size);
   229   this->set_access_flags(access_flags);
   230   this->set_is_anonymous(is_anonymous);
   231   assert(this->size() == size, "wrong size for object");
   233   this->set_array_klasses(NULL);
   234   this->set_methods(NULL);
   235   this->set_method_ordering(NULL);
   236   this->set_local_interfaces(NULL);
   237   this->set_transitive_interfaces(NULL);
   238   this->init_implementor();
   239   this->set_fields(NULL, 0);
   240   this->set_constants(NULL);
   241   this->set_class_loader_data(NULL);
   242   this->set_protection_domain(NULL);
   243   this->set_signers(NULL);
   244   this->set_source_file_name(NULL);
   245   this->set_source_debug_extension(NULL, 0);
   246   this->set_array_name(NULL);
   247   this->set_inner_classes(NULL);
   248   this->set_static_oop_field_count(0);
   249   this->set_nonstatic_field_size(0);
   250   this->set_is_marked_dependent(false);
   251   this->set_init_state(InstanceKlass::allocated);
   252   this->set_init_thread(NULL);
   253   this->set_init_lock(NULL);
   254   this->set_reference_type(rt);
   255   this->set_oop_map_cache(NULL);
   256   this->set_jni_ids(NULL);
   257   this->set_osr_nmethods_head(NULL);
   258   this->set_breakpoints(NULL);
   259   this->init_previous_versions();
   260   this->set_generic_signature(NULL);
   261   this->release_set_methods_jmethod_ids(NULL);
   262   this->release_set_methods_cached_itable_indices(NULL);
   263   this->set_annotations(NULL);
   264   this->set_jvmti_cached_class_field_map(NULL);
   265   this->set_initial_method_idnum(0);
   267   // initialize the non-header words to zero
   268   intptr_t* p = (intptr_t*)this;
   269   for (int index = InstanceKlass::header_size(); index < size; index++) {
   270     p[index] = NULL_WORD;
   271   }
   273   // Set temporary value until parseClassFile updates it with the real instance
   274   // size.
   275   this->set_layout_helper(Klass::instance_layout_helper(0, true));
   276 }
   279 // This function deallocates the metadata and C heap pointers that the
   280 // InstanceKlass points to.
   281 void InstanceKlass::deallocate_contents(ClassLoaderData* loader_data) {
   283   // Orphan the mirror first, CMS thinks it's still live.
   284   java_lang_Class::set_klass(java_mirror(), NULL);
   286   // Need to take this class off the class loader data list.
   287   loader_data->remove_class(this);
   289   // The array_klass for this class is created later, after error handling.
   290   // For class redefinition, we keep the original class so this scratch class
   291   // doesn't have an array class.  Either way, assert that there is nothing
   292   // to deallocate.
   293   assert(array_klasses() == NULL, "array classes shouldn't be created for this class yet");
   295   // Release C heap allocated data that this might point to, which includes
   296   // reference counting symbol names.
   297   release_C_heap_structures();
   299   Array<Method*>* ms = methods();
   300   if (ms != Universe::the_empty_method_array()) {
   301     for (int i = 0; i <= methods()->length() -1 ; i++) {
   302       Method* method = methods()->at(i);
   303       // Only want to delete methods that are not executing for RedefineClasses.
   304       // The previous version will point to them so they're not totally dangling
   305       assert (!method->on_stack(), "shouldn't be called with methods on stack");
   306       MetadataFactory::free_metadata(loader_data, method);
   307     }
   308     MetadataFactory::free_array<Method*>(loader_data, methods());
   309   }
   310   set_methods(NULL);
   312   if (method_ordering() != Universe::the_empty_int_array()) {
   313     MetadataFactory::free_array<int>(loader_data, method_ordering());
   314   }
   315   set_method_ordering(NULL);
   317   // This array is in Klass, but remove it with the InstanceKlass since
   318   // this place would be the only caller and it can share memory with transitive
   319   // interfaces.
   320   if (secondary_supers() != Universe::the_empty_klass_array() &&
   321       secondary_supers() != transitive_interfaces()) {
   322     MetadataFactory::free_array<Klass*>(loader_data, secondary_supers());
   323   }
   324   set_secondary_supers(NULL);
   326   // Only deallocate transitive interfaces if not empty, same as super class
   327   // or same as local interfaces.   See code in parseClassFile.
   328   Array<Klass*>* ti = transitive_interfaces();
   329   if (ti != Universe::the_empty_klass_array() && ti != local_interfaces()) {
   330     // check that the interfaces don't come from super class
   331     Array<Klass*>* sti = (super() == NULL) ? NULL :
   332        InstanceKlass::cast(super())->transitive_interfaces();
   333     if (ti != sti) {
   334       MetadataFactory::free_array<Klass*>(loader_data, ti);
   335     }
   336   }
   337   set_transitive_interfaces(NULL);
   339   // local interfaces can be empty
   340   Array<Klass*>* li = local_interfaces();
   341   if (li != Universe::the_empty_klass_array()) {
   342     MetadataFactory::free_array<Klass*>(loader_data, li);
   343   }
   344   set_local_interfaces(NULL);
   346   MetadataFactory::free_array<jushort>(loader_data, fields());
   347   set_fields(NULL, 0);
   349   // If a method from a redefined class is using this constant pool, don't
   350   // delete it, yet.  The new class's previous version will point to this.
   351   assert (!constants()->on_stack(), "shouldn't be called if anything is onstack");
   352   MetadataFactory::free_metadata(loader_data, constants());
   353   set_constants(NULL);
   355   if (inner_classes() != Universe::the_empty_short_array()) {
   356     MetadataFactory::free_array<jushort>(loader_data, inner_classes());
   357   }
   358   set_inner_classes(NULL);
   360   // Null out Java heap objects, although these won't be walked to keep
   361   // alive once this InstanceKlass is deallocated.
   362   set_protection_domain(NULL);
   363   set_signers(NULL);
   364   set_init_lock(NULL);
   366   // We should deallocate the Annotations instance
   367   MetadataFactory::free_metadata(loader_data, annotations());
   368   set_annotations(NULL);
   369 }
   371 volatile oop InstanceKlass::init_lock() const {
   372   volatile oop lock = _init_lock;  // read once
   373   assert((oop)lock != NULL || !is_not_initialized(), // initialized or in_error state
   374          "only fully initialized state can have a null lock");
   375   return lock;
   376 }
   378 // Set the initialization lock to null so the object can be GC'ed.  Any racing
   379 // threads to get this lock will see a null lock and will not lock.
   380 // That's okay because they all check for initialized state after getting
   381 // the lock and return.
   382 void InstanceKlass::fence_and_clear_init_lock() {
   383   // make sure previous stores are all done, notably the init_state.
   384   OrderAccess::storestore();
   385   klass_oop_store(&_init_lock, NULL);
   386   assert(!is_not_initialized(), "class must be initialized now");
   387 }
   390 bool InstanceKlass::should_be_initialized() const {
   391   return !is_initialized();
   392 }
   394 klassVtable* InstanceKlass::vtable() const {
   395   return new klassVtable(this, start_of_vtable(), vtable_length() / vtableEntry::size());
   396 }
   398 klassItable* InstanceKlass::itable() const {
   399   return new klassItable(instanceKlassHandle(this));
   400 }
   402 void InstanceKlass::eager_initialize(Thread *thread) {
   403   if (!EagerInitialization) return;
   405   if (this->is_not_initialized()) {
   406     // abort if the the class has a class initializer
   407     if (this->class_initializer() != NULL) return;
   409     // abort if it is java.lang.Object (initialization is handled in genesis)
   410     Klass* super = this->super();
   411     if (super == NULL) return;
   413     // abort if the super class should be initialized
   414     if (!InstanceKlass::cast(super)->is_initialized()) return;
   416     // call body to expose the this pointer
   417     instanceKlassHandle this_oop(thread, this);
   418     eager_initialize_impl(this_oop);
   419   }
   420 }
   423 void InstanceKlass::eager_initialize_impl(instanceKlassHandle this_oop) {
   424   EXCEPTION_MARK;
   425   volatile oop init_lock = this_oop->init_lock();
   426   ObjectLocker ol(init_lock, THREAD, init_lock != NULL);
   428   // abort if someone beat us to the initialization
   429   if (!this_oop->is_not_initialized()) return;  // note: not equivalent to is_initialized()
   431   ClassState old_state = this_oop->init_state();
   432   link_class_impl(this_oop, true, THREAD);
   433   if (HAS_PENDING_EXCEPTION) {
   434     CLEAR_PENDING_EXCEPTION;
   435     // Abort if linking the class throws an exception.
   437     // Use a test to avoid redundantly resetting the state if there's
   438     // no change.  Set_init_state() asserts that state changes make
   439     // progress, whereas here we might just be spinning in place.
   440     if( old_state != this_oop->_init_state )
   441       this_oop->set_init_state (old_state);
   442   } else {
   443     // linking successfull, mark class as initialized
   444     this_oop->set_init_state (fully_initialized);
   445     this_oop->fence_and_clear_init_lock();
   446     // trace
   447     if (TraceClassInitialization) {
   448       ResourceMark rm(THREAD);
   449       tty->print_cr("[Initialized %s without side effects]", this_oop->external_name());
   450     }
   451   }
   452 }
   455 // See "The Virtual Machine Specification" section 2.16.5 for a detailed explanation of the class initialization
   456 // process. The step comments refers to the procedure described in that section.
   457 // Note: implementation moved to static method to expose the this pointer.
   458 void InstanceKlass::initialize(TRAPS) {
   459   if (this->should_be_initialized()) {
   460     HandleMark hm(THREAD);
   461     instanceKlassHandle this_oop(THREAD, this);
   462     initialize_impl(this_oop, CHECK);
   463     // Note: at this point the class may be initialized
   464     //       OR it may be in the state of being initialized
   465     //       in case of recursive initialization!
   466   } else {
   467     assert(is_initialized(), "sanity check");
   468   }
   469 }
   472 bool InstanceKlass::verify_code(
   473     instanceKlassHandle this_oop, bool throw_verifyerror, TRAPS) {
   474   // 1) Verify the bytecodes
   475   Verifier::Mode mode =
   476     throw_verifyerror ? Verifier::ThrowException : Verifier::NoException;
   477   return Verifier::verify(this_oop, mode, this_oop->should_verify_class(), CHECK_false);
   478 }
   481 // Used exclusively by the shared spaces dump mechanism to prevent
   482 // classes mapped into the shared regions in new VMs from appearing linked.
   484 void InstanceKlass::unlink_class() {
   485   assert(is_linked(), "must be linked");
   486   _init_state = loaded;
   487 }
   489 void InstanceKlass::link_class(TRAPS) {
   490   assert(is_loaded(), "must be loaded");
   491   if (!is_linked()) {
   492     HandleMark hm(THREAD);
   493     instanceKlassHandle this_oop(THREAD, this);
   494     link_class_impl(this_oop, true, CHECK);
   495   }
   496 }
   498 // Called to verify that a class can link during initialization, without
   499 // throwing a VerifyError.
   500 bool InstanceKlass::link_class_or_fail(TRAPS) {
   501   assert(is_loaded(), "must be loaded");
   502   if (!is_linked()) {
   503     HandleMark hm(THREAD);
   504     instanceKlassHandle this_oop(THREAD, this);
   505     link_class_impl(this_oop, false, CHECK_false);
   506   }
   507   return is_linked();
   508 }
   510 bool InstanceKlass::link_class_impl(
   511     instanceKlassHandle this_oop, bool throw_verifyerror, TRAPS) {
   512   // check for error state
   513   if (this_oop->is_in_error_state()) {
   514     ResourceMark rm(THREAD);
   515     THROW_MSG_(vmSymbols::java_lang_NoClassDefFoundError(),
   516                this_oop->external_name(), false);
   517   }
   518   // return if already verified
   519   if (this_oop->is_linked()) {
   520     return true;
   521   }
   523   // Timing
   524   // timer handles recursion
   525   assert(THREAD->is_Java_thread(), "non-JavaThread in link_class_impl");
   526   JavaThread* jt = (JavaThread*)THREAD;
   528   // link super class before linking this class
   529   instanceKlassHandle super(THREAD, this_oop->super());
   530   if (super.not_null()) {
   531     if (super->is_interface()) {  // check if super class is an interface
   532       ResourceMark rm(THREAD);
   533       Exceptions::fthrow(
   534         THREAD_AND_LOCATION,
   535         vmSymbols::java_lang_IncompatibleClassChangeError(),
   536         "class %s has interface %s as super class",
   537         this_oop->external_name(),
   538         super->external_name()
   539       );
   540       return false;
   541     }
   543     link_class_impl(super, throw_verifyerror, CHECK_false);
   544   }
   546   // link all interfaces implemented by this class before linking this class
   547   Array<Klass*>* interfaces = this_oop->local_interfaces();
   548   int num_interfaces = interfaces->length();
   549   for (int index = 0; index < num_interfaces; index++) {
   550     HandleMark hm(THREAD);
   551     instanceKlassHandle ih(THREAD, interfaces->at(index));
   552     link_class_impl(ih, throw_verifyerror, CHECK_false);
   553   }
   555   // in case the class is linked in the process of linking its superclasses
   556   if (this_oop->is_linked()) {
   557     return true;
   558   }
   560   // trace only the link time for this klass that includes
   561   // the verification time
   562   PerfClassTraceTime vmtimer(ClassLoader::perf_class_link_time(),
   563                              ClassLoader::perf_class_link_selftime(),
   564                              ClassLoader::perf_classes_linked(),
   565                              jt->get_thread_stat()->perf_recursion_counts_addr(),
   566                              jt->get_thread_stat()->perf_timers_addr(),
   567                              PerfClassTraceTime::CLASS_LINK);
   569   // verification & rewriting
   570   {
   571     volatile oop init_lock = this_oop->init_lock();
   572     ObjectLocker ol(init_lock, THREAD, init_lock != NULL);
   573     // rewritten will have been set if loader constraint error found
   574     // on an earlier link attempt
   575     // don't verify or rewrite if already rewritten
   577     if (!this_oop->is_linked()) {
   578       if (!this_oop->is_rewritten()) {
   579         {
   580           // Timer includes any side effects of class verification (resolution,
   581           // etc), but not recursive entry into verify_code().
   582           PerfClassTraceTime timer(ClassLoader::perf_class_verify_time(),
   583                                    ClassLoader::perf_class_verify_selftime(),
   584                                    ClassLoader::perf_classes_verified(),
   585                                    jt->get_thread_stat()->perf_recursion_counts_addr(),
   586                                    jt->get_thread_stat()->perf_timers_addr(),
   587                                    PerfClassTraceTime::CLASS_VERIFY);
   588           bool verify_ok = verify_code(this_oop, throw_verifyerror, THREAD);
   589           if (!verify_ok) {
   590             return false;
   591           }
   592         }
   594         // Just in case a side-effect of verify linked this class already
   595         // (which can sometimes happen since the verifier loads classes
   596         // using custom class loaders, which are free to initialize things)
   597         if (this_oop->is_linked()) {
   598           return true;
   599         }
   601         // also sets rewritten
   602         this_oop->rewrite_class(CHECK_false);
   603       }
   605       // relocate jsrs and link methods after they are all rewritten
   606       this_oop->link_methods(CHECK_false);
   608       // Initialize the vtable and interface table after
   609       // methods have been rewritten since rewrite may
   610       // fabricate new Method*s.
   611       // also does loader constraint checking
   612       if (!this_oop()->is_shared()) {
   613         ResourceMark rm(THREAD);
   614         this_oop->vtable()->initialize_vtable(true, CHECK_false);
   615         this_oop->itable()->initialize_itable(true, CHECK_false);
   616       }
   617 #ifdef ASSERT
   618       else {
   619         ResourceMark rm(THREAD);
   620         this_oop->vtable()->verify(tty, true);
   621         // In case itable verification is ever added.
   622         // this_oop->itable()->verify(tty, true);
   623       }
   624 #endif
   625       this_oop->set_init_state(linked);
   626       if (JvmtiExport::should_post_class_prepare()) {
   627         Thread *thread = THREAD;
   628         assert(thread->is_Java_thread(), "thread->is_Java_thread()");
   629         JvmtiExport::post_class_prepare((JavaThread *) thread, this_oop());
   630       }
   631     }
   632   }
   633   return true;
   634 }
   637 // Rewrite the byte codes of all of the methods of a class.
   638 // The rewriter must be called exactly once. Rewriting must happen after
   639 // verification but before the first method of the class is executed.
   640 void InstanceKlass::rewrite_class(TRAPS) {
   641   assert(is_loaded(), "must be loaded");
   642   instanceKlassHandle this_oop(THREAD, this);
   643   if (this_oop->is_rewritten()) {
   644     assert(this_oop()->is_shared(), "rewriting an unshared class?");
   645     return;
   646   }
   647   Rewriter::rewrite(this_oop, CHECK);
   648   this_oop->set_rewritten();
   649 }
   651 // Now relocate and link method entry points after class is rewritten.
   652 // This is outside is_rewritten flag. In case of an exception, it can be
   653 // executed more than once.
   654 void InstanceKlass::link_methods(TRAPS) {
   655   int len = methods()->length();
   656   for (int i = len-1; i >= 0; i--) {
   657     methodHandle m(THREAD, methods()->at(i));
   659     // Set up method entry points for compiler and interpreter    .
   660     m->link_method(m, CHECK);
   662     // This is for JVMTI and unrelated to relocator but the last thing we do
   663 #ifdef ASSERT
   664     if (StressMethodComparator) {
   665       ResourceMark rm(THREAD);
   666       static int nmc = 0;
   667       for (int j = i; j >= 0 && j >= i-4; j--) {
   668         if ((++nmc % 1000) == 0)  tty->print_cr("Have run MethodComparator %d times...", nmc);
   669         bool z = MethodComparator::methods_EMCP(m(),
   670                    methods()->at(j));
   671         if (j == i && !z) {
   672           tty->print("MethodComparator FAIL: "); m->print(); m->print_codes();
   673           assert(z, "method must compare equal to itself");
   674         }
   675       }
   676     }
   677 #endif //ASSERT
   678   }
   679 }
   682 void InstanceKlass::initialize_impl(instanceKlassHandle this_oop, TRAPS) {
   683   // Make sure klass is linked (verified) before initialization
   684   // A class could already be verified, since it has been reflected upon.
   685   this_oop->link_class(CHECK);
   687   DTRACE_CLASSINIT_PROBE(required, InstanceKlass::cast(this_oop()), -1);
   689   bool wait = false;
   691   // refer to the JVM book page 47 for description of steps
   692   // Step 1
   693   {
   694     volatile oop init_lock = this_oop->init_lock();
   695     ObjectLocker ol(init_lock, THREAD, init_lock != NULL);
   697     Thread *self = THREAD; // it's passed the current thread
   699     // Step 2
   700     // If we were to use wait() instead of waitInterruptibly() then
   701     // we might end up throwing IE from link/symbol resolution sites
   702     // that aren't expected to throw.  This would wreak havoc.  See 6320309.
   703     while(this_oop->is_being_initialized() && !this_oop->is_reentrant_initialization(self)) {
   704         wait = true;
   705       ol.waitUninterruptibly(CHECK);
   706     }
   708     // Step 3
   709     if (this_oop->is_being_initialized() && this_oop->is_reentrant_initialization(self)) {
   710       DTRACE_CLASSINIT_PROBE_WAIT(recursive, InstanceKlass::cast(this_oop()), -1,wait);
   711       return;
   712     }
   714     // Step 4
   715     if (this_oop->is_initialized()) {
   716       DTRACE_CLASSINIT_PROBE_WAIT(concurrent, InstanceKlass::cast(this_oop()), -1,wait);
   717       return;
   718     }
   720     // Step 5
   721     if (this_oop->is_in_error_state()) {
   722       DTRACE_CLASSINIT_PROBE_WAIT(erroneous, InstanceKlass::cast(this_oop()), -1,wait);
   723       ResourceMark rm(THREAD);
   724       const char* desc = "Could not initialize class ";
   725       const char* className = this_oop->external_name();
   726       size_t msglen = strlen(desc) + strlen(className) + 1;
   727       char* message = NEW_RESOURCE_ARRAY(char, msglen);
   728       if (NULL == message) {
   729         // Out of memory: can't create detailed error message
   730         THROW_MSG(vmSymbols::java_lang_NoClassDefFoundError(), className);
   731       } else {
   732         jio_snprintf(message, msglen, "%s%s", desc, className);
   733         THROW_MSG(vmSymbols::java_lang_NoClassDefFoundError(), message);
   734       }
   735     }
   737     // Step 6
   738     this_oop->set_init_state(being_initialized);
   739     this_oop->set_init_thread(self);
   740   }
   742   // Step 7
   743   Klass* super_klass = this_oop->super();
   744   if (super_klass != NULL && !this_oop->is_interface() && super_klass->should_be_initialized()) {
   745     super_klass->initialize(THREAD);
   747     if (HAS_PENDING_EXCEPTION) {
   748       Handle e(THREAD, PENDING_EXCEPTION);
   749       CLEAR_PENDING_EXCEPTION;
   750       {
   751         EXCEPTION_MARK;
   752         this_oop->set_initialization_state_and_notify(initialization_error, THREAD); // Locks object, set state, and notify all waiting threads
   753         CLEAR_PENDING_EXCEPTION;   // ignore any exception thrown, superclass initialization error is thrown below
   754       }
   755       DTRACE_CLASSINIT_PROBE_WAIT(super__failed, InstanceKlass::cast(this_oop()), -1,wait);
   756       THROW_OOP(e());
   757     }
   758   }
   760   if (this_oop->has_default_methods()) {
   761     // Step 7.5: initialize any interfaces which have default methods
   762     for (int i = 0; i < this_oop->local_interfaces()->length(); ++i) {
   763       Klass* iface = this_oop->local_interfaces()->at(i);
   764       InstanceKlass* ik = InstanceKlass::cast(iface);
   765       if (ik->has_default_methods() && ik->should_be_initialized()) {
   766         ik->initialize(THREAD);
   768         if (HAS_PENDING_EXCEPTION) {
   769           Handle e(THREAD, PENDING_EXCEPTION);
   770           CLEAR_PENDING_EXCEPTION;
   771           {
   772             EXCEPTION_MARK;
   773             // Locks object, set state, and notify all waiting threads
   774             this_oop->set_initialization_state_and_notify(
   775                 initialization_error, THREAD);
   777             // ignore any exception thrown, superclass initialization error is
   778             // thrown below
   779             CLEAR_PENDING_EXCEPTION;
   780           }
   781           DTRACE_CLASSINIT_PROBE_WAIT(
   782               super__failed, InstanceKlass::cast(this_oop()), -1, wait);
   783           THROW_OOP(e());
   784         }
   785       }
   786     }
   787   }
   789   // Step 8
   790   {
   791     assert(THREAD->is_Java_thread(), "non-JavaThread in initialize_impl");
   792     JavaThread* jt = (JavaThread*)THREAD;
   793     DTRACE_CLASSINIT_PROBE_WAIT(clinit, InstanceKlass::cast(this_oop()), -1,wait);
   794     // Timer includes any side effects of class initialization (resolution,
   795     // etc), but not recursive entry into call_class_initializer().
   796     PerfClassTraceTime timer(ClassLoader::perf_class_init_time(),
   797                              ClassLoader::perf_class_init_selftime(),
   798                              ClassLoader::perf_classes_inited(),
   799                              jt->get_thread_stat()->perf_recursion_counts_addr(),
   800                              jt->get_thread_stat()->perf_timers_addr(),
   801                              PerfClassTraceTime::CLASS_CLINIT);
   802     this_oop->call_class_initializer(THREAD);
   803   }
   805   // Step 9
   806   if (!HAS_PENDING_EXCEPTION) {
   807     this_oop->set_initialization_state_and_notify(fully_initialized, CHECK);
   808     { ResourceMark rm(THREAD);
   809       debug_only(this_oop->vtable()->verify(tty, true);)
   810     }
   811   }
   812   else {
   813     // Step 10 and 11
   814     Handle e(THREAD, PENDING_EXCEPTION);
   815     CLEAR_PENDING_EXCEPTION;
   816     {
   817       EXCEPTION_MARK;
   818       this_oop->set_initialization_state_and_notify(initialization_error, THREAD);
   819       CLEAR_PENDING_EXCEPTION;   // ignore any exception thrown, class initialization error is thrown below
   820     }
   821     DTRACE_CLASSINIT_PROBE_WAIT(error, InstanceKlass::cast(this_oop()), -1,wait);
   822     if (e->is_a(SystemDictionary::Error_klass())) {
   823       THROW_OOP(e());
   824     } else {
   825       JavaCallArguments args(e);
   826       THROW_ARG(vmSymbols::java_lang_ExceptionInInitializerError(),
   827                 vmSymbols::throwable_void_signature(),
   828                 &args);
   829     }
   830   }
   831   DTRACE_CLASSINIT_PROBE_WAIT(end, InstanceKlass::cast(this_oop()), -1,wait);
   832 }
   835 // Note: implementation moved to static method to expose the this pointer.
   836 void InstanceKlass::set_initialization_state_and_notify(ClassState state, TRAPS) {
   837   instanceKlassHandle kh(THREAD, this);
   838   set_initialization_state_and_notify_impl(kh, state, CHECK);
   839 }
   841 void InstanceKlass::set_initialization_state_and_notify_impl(instanceKlassHandle this_oop, ClassState state, TRAPS) {
   842   volatile oop init_lock = this_oop->init_lock();
   843   ObjectLocker ol(init_lock, THREAD, init_lock != NULL);
   844   this_oop->set_init_state(state);
   845   this_oop->fence_and_clear_init_lock();
   846   ol.notify_all(CHECK);
   847 }
   849 // The embedded _implementor field can only record one implementor.
   850 // When there are more than one implementors, the _implementor field
   851 // is set to the interface Klass* itself. Following are the possible
   852 // values for the _implementor field:
   853 //   NULL                  - no implementor
   854 //   implementor Klass*    - one implementor
   855 //   self                  - more than one implementor
   856 //
   857 // The _implementor field only exists for interfaces.
   858 void InstanceKlass::add_implementor(Klass* k) {
   859   assert(Compile_lock->owned_by_self(), "");
   860   assert(is_interface(), "not interface");
   861   // Filter out my subinterfaces.
   862   // (Note: Interfaces are never on the subklass list.)
   863   if (InstanceKlass::cast(k)->is_interface()) return;
   865   // Filter out subclasses whose supers already implement me.
   866   // (Note: CHA must walk subclasses of direct implementors
   867   // in order to locate indirect implementors.)
   868   Klass* sk = InstanceKlass::cast(k)->super();
   869   if (sk != NULL && InstanceKlass::cast(sk)->implements_interface(this))
   870     // We only need to check one immediate superclass, since the
   871     // implements_interface query looks at transitive_interfaces.
   872     // Any supers of the super have the same (or fewer) transitive_interfaces.
   873     return;
   875   Klass* ik = implementor();
   876   if (ik == NULL) {
   877     set_implementor(k);
   878   } else if (ik != this) {
   879     // There is already an implementor. Use itself as an indicator of
   880     // more than one implementors.
   881     set_implementor(this);
   882   }
   884   // The implementor also implements the transitive_interfaces
   885   for (int index = 0; index < local_interfaces()->length(); index++) {
   886     InstanceKlass::cast(local_interfaces()->at(index))->add_implementor(k);
   887   }
   888 }
   890 void InstanceKlass::init_implementor() {
   891   if (is_interface()) {
   892     set_implementor(NULL);
   893   }
   894 }
   897 void InstanceKlass::process_interfaces(Thread *thread) {
   898   // link this class into the implementors list of every interface it implements
   899   Klass* this_as_klass_oop = this;
   900   for (int i = local_interfaces()->length() - 1; i >= 0; i--) {
   901     assert(local_interfaces()->at(i)->is_klass(), "must be a klass");
   902     InstanceKlass* interf = InstanceKlass::cast(local_interfaces()->at(i));
   903     assert(interf->is_interface(), "expected interface");
   904     interf->add_implementor(this_as_klass_oop);
   905   }
   906 }
   908 bool InstanceKlass::can_be_primary_super_slow() const {
   909   if (is_interface())
   910     return false;
   911   else
   912     return Klass::can_be_primary_super_slow();
   913 }
   915 GrowableArray<Klass*>* InstanceKlass::compute_secondary_supers(int num_extra_slots) {
   916   // The secondaries are the implemented interfaces.
   917   InstanceKlass* ik = InstanceKlass::cast(this);
   918   Array<Klass*>* interfaces = ik->transitive_interfaces();
   919   int num_secondaries = num_extra_slots + interfaces->length();
   920   if (num_secondaries == 0) {
   921     // Must share this for correct bootstrapping!
   922     set_secondary_supers(Universe::the_empty_klass_array());
   923     return NULL;
   924   } else if (num_extra_slots == 0) {
   925     // The secondary super list is exactly the same as the transitive interfaces.
   926     // Redefine classes has to be careful not to delete this!
   927     set_secondary_supers(interfaces);
   928     return NULL;
   929   } else {
   930     // Copy transitive interfaces to a temporary growable array to be constructed
   931     // into the secondary super list with extra slots.
   932     GrowableArray<Klass*>* secondaries = new GrowableArray<Klass*>(interfaces->length());
   933     for (int i = 0; i < interfaces->length(); i++) {
   934       secondaries->push(interfaces->at(i));
   935     }
   936     return secondaries;
   937   }
   938 }
   940 bool InstanceKlass::compute_is_subtype_of(Klass* k) {
   941   if (k->is_interface()) {
   942     return implements_interface(k);
   943   } else {
   944     return Klass::compute_is_subtype_of(k);
   945   }
   946 }
   948 bool InstanceKlass::implements_interface(Klass* k) const {
   949   if (this == k) return true;
   950   assert(k->is_interface(), "should be an interface class");
   951   for (int i = 0; i < transitive_interfaces()->length(); i++) {
   952     if (transitive_interfaces()->at(i) == k) {
   953       return true;
   954     }
   955   }
   956   return false;
   957 }
   959 objArrayOop InstanceKlass::allocate_objArray(int n, int length, TRAPS) {
   960   if (length < 0) THROW_0(vmSymbols::java_lang_NegativeArraySizeException());
   961   if (length > arrayOopDesc::max_array_length(T_OBJECT)) {
   962     report_java_out_of_memory("Requested array size exceeds VM limit");
   963     JvmtiExport::post_array_size_exhausted();
   964     THROW_OOP_0(Universe::out_of_memory_error_array_size());
   965   }
   966   int size = objArrayOopDesc::object_size(length);
   967   Klass* ak = array_klass(n, CHECK_NULL);
   968   KlassHandle h_ak (THREAD, ak);
   969   objArrayOop o =
   970     (objArrayOop)CollectedHeap::array_allocate(h_ak, size, length, CHECK_NULL);
   971   return o;
   972 }
   974 instanceOop InstanceKlass::register_finalizer(instanceOop i, TRAPS) {
   975   if (TraceFinalizerRegistration) {
   976     tty->print("Registered ");
   977     i->print_value_on(tty);
   978     tty->print_cr(" (" INTPTR_FORMAT ") as finalizable", (address)i);
   979   }
   980   instanceHandle h_i(THREAD, i);
   981   // Pass the handle as argument, JavaCalls::call expects oop as jobjects
   982   JavaValue result(T_VOID);
   983   JavaCallArguments args(h_i);
   984   methodHandle mh (THREAD, Universe::finalizer_register_method());
   985   JavaCalls::call(&result, mh, &args, CHECK_NULL);
   986   return h_i();
   987 }
   989 instanceOop InstanceKlass::allocate_instance(TRAPS) {
   990   bool has_finalizer_flag = has_finalizer(); // Query before possible GC
   991   int size = size_helper();  // Query before forming handle.
   993   KlassHandle h_k(THREAD, this);
   995   instanceOop i;
   997   i = (instanceOop)CollectedHeap::obj_allocate(h_k, size, CHECK_NULL);
   998   if (has_finalizer_flag && !RegisterFinalizersAtInit) {
   999     i = register_finalizer(i, CHECK_NULL);
  1001   return i;
  1004 void InstanceKlass::check_valid_for_instantiation(bool throwError, TRAPS) {
  1005   if (is_interface() || is_abstract()) {
  1006     ResourceMark rm(THREAD);
  1007     THROW_MSG(throwError ? vmSymbols::java_lang_InstantiationError()
  1008               : vmSymbols::java_lang_InstantiationException(), external_name());
  1010   if (this == SystemDictionary::Class_klass()) {
  1011     ResourceMark rm(THREAD);
  1012     THROW_MSG(throwError ? vmSymbols::java_lang_IllegalAccessError()
  1013               : vmSymbols::java_lang_IllegalAccessException(), external_name());
  1017 Klass* InstanceKlass::array_klass_impl(bool or_null, int n, TRAPS) {
  1018   instanceKlassHandle this_oop(THREAD, this);
  1019   return array_klass_impl(this_oop, or_null, n, THREAD);
  1022 Klass* InstanceKlass::array_klass_impl(instanceKlassHandle this_oop, bool or_null, int n, TRAPS) {
  1023   if (this_oop->array_klasses() == NULL) {
  1024     if (or_null) return NULL;
  1026     ResourceMark rm;
  1027     JavaThread *jt = (JavaThread *)THREAD;
  1029       // Atomic creation of array_klasses
  1030       MutexLocker mc(Compile_lock, THREAD);   // for vtables
  1031       MutexLocker ma(MultiArray_lock, THREAD);
  1033       // Check if update has already taken place
  1034       if (this_oop->array_klasses() == NULL) {
  1035         Klass*    k = ObjArrayKlass::allocate_objArray_klass(this_oop->class_loader_data(), 1, this_oop, CHECK_NULL);
  1036         this_oop->set_array_klasses(k);
  1040   // _this will always be set at this point
  1041   ObjArrayKlass* oak = (ObjArrayKlass*)this_oop->array_klasses();
  1042   if (or_null) {
  1043     return oak->array_klass_or_null(n);
  1045   return oak->array_klass(n, CHECK_NULL);
  1048 Klass* InstanceKlass::array_klass_impl(bool or_null, TRAPS) {
  1049   return array_klass_impl(or_null, 1, THREAD);
  1052 void InstanceKlass::call_class_initializer(TRAPS) {
  1053   instanceKlassHandle ik (THREAD, this);
  1054   call_class_initializer_impl(ik, THREAD);
  1057 static int call_class_initializer_impl_counter = 0;   // for debugging
  1059 Method* InstanceKlass::class_initializer() {
  1060   Method* clinit = find_method(
  1061       vmSymbols::class_initializer_name(), vmSymbols::void_method_signature());
  1062   if (clinit != NULL && clinit->has_valid_initializer_flags()) {
  1063     return clinit;
  1065   return NULL;
  1068 void InstanceKlass::call_class_initializer_impl(instanceKlassHandle this_oop, TRAPS) {
  1069   if (ReplayCompiles &&
  1070       (ReplaySuppressInitializers == 1 ||
  1071        ReplaySuppressInitializers >= 2 && this_oop->class_loader() != NULL)) {
  1072     // Hide the existence of the initializer for the purpose of replaying the compile
  1073     return;
  1076   methodHandle h_method(THREAD, this_oop->class_initializer());
  1077   assert(!this_oop->is_initialized(), "we cannot initialize twice");
  1078   if (TraceClassInitialization) {
  1079     tty->print("%d Initializing ", call_class_initializer_impl_counter++);
  1080     this_oop->name()->print_value();
  1081     tty->print_cr("%s (" INTPTR_FORMAT ")", h_method() == NULL ? "(no method)" : "", (address)this_oop());
  1083   if (h_method() != NULL) {
  1084     JavaCallArguments args; // No arguments
  1085     JavaValue result(T_VOID);
  1086     JavaCalls::call(&result, h_method, &args, CHECK); // Static call (no args)
  1091 void InstanceKlass::mask_for(methodHandle method, int bci,
  1092   InterpreterOopMap* entry_for) {
  1093   // Dirty read, then double-check under a lock.
  1094   if (_oop_map_cache == NULL) {
  1095     // Otherwise, allocate a new one.
  1096     MutexLocker x(OopMapCacheAlloc_lock);
  1097     // First time use. Allocate a cache in C heap
  1098     if (_oop_map_cache == NULL) {
  1099       _oop_map_cache = new OopMapCache();
  1102   // _oop_map_cache is constant after init; lookup below does is own locking.
  1103   _oop_map_cache->lookup(method, bci, entry_for);
  1107 bool InstanceKlass::find_local_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
  1108   for (JavaFieldStream fs(this); !fs.done(); fs.next()) {
  1109     Symbol* f_name = fs.name();
  1110     Symbol* f_sig  = fs.signature();
  1111     if (f_name == name && f_sig == sig) {
  1112       fd->initialize(const_cast<InstanceKlass*>(this), fs.index());
  1113       return true;
  1116   return false;
  1120 Klass* InstanceKlass::find_interface_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
  1121   const int n = local_interfaces()->length();
  1122   for (int i = 0; i < n; i++) {
  1123     Klass* intf1 = local_interfaces()->at(i);
  1124     assert(intf1->is_interface(), "just checking type");
  1125     // search for field in current interface
  1126     if (InstanceKlass::cast(intf1)->find_local_field(name, sig, fd)) {
  1127       assert(fd->is_static(), "interface field must be static");
  1128       return intf1;
  1130     // search for field in direct superinterfaces
  1131     Klass* intf2 = InstanceKlass::cast(intf1)->find_interface_field(name, sig, fd);
  1132     if (intf2 != NULL) return intf2;
  1134   // otherwise field lookup fails
  1135   return NULL;
  1139 Klass* InstanceKlass::find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
  1140   // search order according to newest JVM spec (5.4.3.2, p.167).
  1141   // 1) search for field in current klass
  1142   if (find_local_field(name, sig, fd)) {
  1143     return const_cast<InstanceKlass*>(this);
  1145   // 2) search for field recursively in direct superinterfaces
  1146   { Klass* intf = find_interface_field(name, sig, fd);
  1147     if (intf != NULL) return intf;
  1149   // 3) apply field lookup recursively if superclass exists
  1150   { Klass* supr = super();
  1151     if (supr != NULL) return InstanceKlass::cast(supr)->find_field(name, sig, fd);
  1153   // 4) otherwise field lookup fails
  1154   return NULL;
  1158 Klass* InstanceKlass::find_field(Symbol* name, Symbol* sig, bool is_static, fieldDescriptor* fd) const {
  1159   // search order according to newest JVM spec (5.4.3.2, p.167).
  1160   // 1) search for field in current klass
  1161   if (find_local_field(name, sig, fd)) {
  1162     if (fd->is_static() == is_static) return const_cast<InstanceKlass*>(this);
  1164   // 2) search for field recursively in direct superinterfaces
  1165   if (is_static) {
  1166     Klass* intf = find_interface_field(name, sig, fd);
  1167     if (intf != NULL) return intf;
  1169   // 3) apply field lookup recursively if superclass exists
  1170   { Klass* supr = super();
  1171     if (supr != NULL) return InstanceKlass::cast(supr)->find_field(name, sig, is_static, fd);
  1173   // 4) otherwise field lookup fails
  1174   return NULL;
  1178 bool InstanceKlass::find_local_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const {
  1179   for (JavaFieldStream fs(this); !fs.done(); fs.next()) {
  1180     if (fs.offset() == offset) {
  1181       fd->initialize(const_cast<InstanceKlass*>(this), fs.index());
  1182       if (fd->is_static() == is_static) return true;
  1185   return false;
  1189 bool InstanceKlass::find_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const {
  1190   Klass* klass = const_cast<InstanceKlass*>(this);
  1191   while (klass != NULL) {
  1192     if (InstanceKlass::cast(klass)->find_local_field_from_offset(offset, is_static, fd)) {
  1193       return true;
  1195     klass = klass->super();
  1197   return false;
  1201 void InstanceKlass::methods_do(void f(Method* method)) {
  1202   int len = methods()->length();
  1203   for (int index = 0; index < len; index++) {
  1204     Method* m = methods()->at(index);
  1205     assert(m->is_method(), "must be method");
  1206     f(m);
  1211 void InstanceKlass::do_local_static_fields(FieldClosure* cl) {
  1212   for (JavaFieldStream fs(this); !fs.done(); fs.next()) {
  1213     if (fs.access_flags().is_static()) {
  1214       fieldDescriptor fd;
  1215       fd.initialize(this, fs.index());
  1216       cl->do_field(&fd);
  1222 void InstanceKlass::do_local_static_fields(void f(fieldDescriptor*, TRAPS), TRAPS) {
  1223   instanceKlassHandle h_this(THREAD, this);
  1224   do_local_static_fields_impl(h_this, f, CHECK);
  1228 void InstanceKlass::do_local_static_fields_impl(instanceKlassHandle this_oop, void f(fieldDescriptor* fd, TRAPS), TRAPS) {
  1229   for (JavaFieldStream fs(this_oop()); !fs.done(); fs.next()) {
  1230     if (fs.access_flags().is_static()) {
  1231       fieldDescriptor fd;
  1232       fd.initialize(this_oop(), fs.index());
  1233       f(&fd, CHECK);
  1239 static int compare_fields_by_offset(int* a, int* b) {
  1240   return a[0] - b[0];
  1243 void InstanceKlass::do_nonstatic_fields(FieldClosure* cl) {
  1244   InstanceKlass* super = superklass();
  1245   if (super != NULL) {
  1246     super->do_nonstatic_fields(cl);
  1248   fieldDescriptor fd;
  1249   int length = java_fields_count();
  1250   // In DebugInfo nonstatic fields are sorted by offset.
  1251   int* fields_sorted = NEW_C_HEAP_ARRAY(int, 2*(length+1), mtClass);
  1252   int j = 0;
  1253   for (int i = 0; i < length; i += 1) {
  1254     fd.initialize(this, i);
  1255     if (!fd.is_static()) {
  1256       fields_sorted[j + 0] = fd.offset();
  1257       fields_sorted[j + 1] = i;
  1258       j += 2;
  1261   if (j > 0) {
  1262     length = j;
  1263     // _sort_Fn is defined in growableArray.hpp.
  1264     qsort(fields_sorted, length/2, 2*sizeof(int), (_sort_Fn)compare_fields_by_offset);
  1265     for (int i = 0; i < length; i += 2) {
  1266       fd.initialize(this, fields_sorted[i + 1]);
  1267       assert(!fd.is_static() && fd.offset() == fields_sorted[i], "only nonstatic fields");
  1268       cl->do_field(&fd);
  1271   FREE_C_HEAP_ARRAY(int, fields_sorted, mtClass);
  1275 void InstanceKlass::array_klasses_do(void f(Klass* k, TRAPS), TRAPS) {
  1276   if (array_klasses() != NULL)
  1277     ArrayKlass::cast(array_klasses())->array_klasses_do(f, THREAD);
  1280 void InstanceKlass::array_klasses_do(void f(Klass* k)) {
  1281   if (array_klasses() != NULL)
  1282     ArrayKlass::cast(array_klasses())->array_klasses_do(f);
  1286 void InstanceKlass::with_array_klasses_do(void f(Klass* k)) {
  1287   f(this);
  1288   array_klasses_do(f);
  1291 #ifdef ASSERT
  1292 static int linear_search(Array<Method*>* methods, Symbol* name, Symbol* signature) {
  1293   int len = methods->length();
  1294   for (int index = 0; index < len; index++) {
  1295     Method* m = methods->at(index);
  1296     assert(m->is_method(), "must be method");
  1297     if (m->signature() == signature && m->name() == name) {
  1298        return index;
  1301   return -1;
  1303 #endif
  1305 static int binary_search(Array<Method*>* methods, Symbol* name) {
  1306   int len = methods->length();
  1307   // methods are sorted, so do binary search
  1308   int l = 0;
  1309   int h = len - 1;
  1310   while (l <= h) {
  1311     int mid = (l + h) >> 1;
  1312     Method* m = methods->at(mid);
  1313     assert(m->is_method(), "must be method");
  1314     int res = m->name()->fast_compare(name);
  1315     if (res == 0) {
  1316       return mid;
  1317     } else if (res < 0) {
  1318       l = mid + 1;
  1319     } else {
  1320       h = mid - 1;
  1323   return -1;
  1326 Method* InstanceKlass::find_method(Symbol* name, Symbol* signature) const {
  1327   return InstanceKlass::find_method(methods(), name, signature);
  1330 Method* InstanceKlass::find_method(
  1331     Array<Method*>* methods, Symbol* name, Symbol* signature) {
  1332   int hit = binary_search(methods, name);
  1333   if (hit != -1) {
  1334     Method* m = methods->at(hit);
  1335     // Do linear search to find matching signature.  First, quick check
  1336     // for common case
  1337     if (m->signature() == signature) return m;
  1338     // search downwards through overloaded methods
  1339     int i;
  1340     for (i = hit - 1; i >= 0; --i) {
  1341         Method* m = methods->at(i);
  1342         assert(m->is_method(), "must be method");
  1343         if (m->name() != name) break;
  1344         if (m->signature() == signature) return m;
  1346     // search upwards
  1347     for (i = hit + 1; i < methods->length(); ++i) {
  1348         Method* m = methods->at(i);
  1349         assert(m->is_method(), "must be method");
  1350         if (m->name() != name) break;
  1351         if (m->signature() == signature) return m;
  1353     // not found
  1354 #ifdef ASSERT
  1355     int index = linear_search(methods, name, signature);
  1356     assert(index == -1, err_msg("binary search should have found entry %d", index));
  1357 #endif
  1359   return NULL;
  1362 int InstanceKlass::find_method_by_name(Symbol* name, int* end) {
  1363   return find_method_by_name(methods(), name, end);
  1366 int InstanceKlass::find_method_by_name(
  1367     Array<Method*>* methods, Symbol* name, int* end_ptr) {
  1368   assert(end_ptr != NULL, "just checking");
  1369   int start = binary_search(methods, name);
  1370   int end = start + 1;
  1371   if (start != -1) {
  1372     while (start - 1 >= 0 && (methods->at(start - 1))->name() == name) --start;
  1373     while (end < methods->length() && (methods->at(end))->name() == name) ++end;
  1374     *end_ptr = end;
  1375     return start;
  1377   return -1;
  1380 Method* InstanceKlass::uncached_lookup_method(Symbol* name, Symbol* signature) const {
  1381   Klass* klass = const_cast<InstanceKlass*>(this);
  1382   while (klass != NULL) {
  1383     Method* method = InstanceKlass::cast(klass)->find_method(name, signature);
  1384     if (method != NULL) return method;
  1385     klass = InstanceKlass::cast(klass)->super();
  1387   return NULL;
  1390 // lookup a method in all the interfaces that this class implements
  1391 Method* InstanceKlass::lookup_method_in_all_interfaces(Symbol* name,
  1392                                                          Symbol* signature) const {
  1393   Array<Klass*>* all_ifs = transitive_interfaces();
  1394   int num_ifs = all_ifs->length();
  1395   InstanceKlass *ik = NULL;
  1396   for (int i = 0; i < num_ifs; i++) {
  1397     ik = InstanceKlass::cast(all_ifs->at(i));
  1398     Method* m = ik->lookup_method(name, signature);
  1399     if (m != NULL) {
  1400       return m;
  1403   return NULL;
  1406 /* jni_id_for_impl for jfieldIds only */
  1407 JNIid* InstanceKlass::jni_id_for_impl(instanceKlassHandle this_oop, int offset) {
  1408   MutexLocker ml(JfieldIdCreation_lock);
  1409   // Retry lookup after we got the lock
  1410   JNIid* probe = this_oop->jni_ids() == NULL ? NULL : this_oop->jni_ids()->find(offset);
  1411   if (probe == NULL) {
  1412     // Slow case, allocate new static field identifier
  1413     probe = new JNIid(this_oop(), offset, this_oop->jni_ids());
  1414     this_oop->set_jni_ids(probe);
  1416   return probe;
  1420 /* jni_id_for for jfieldIds only */
  1421 JNIid* InstanceKlass::jni_id_for(int offset) {
  1422   JNIid* probe = jni_ids() == NULL ? NULL : jni_ids()->find(offset);
  1423   if (probe == NULL) {
  1424     probe = jni_id_for_impl(this, offset);
  1426   return probe;
  1429 u2 InstanceKlass::enclosing_method_data(int offset) {
  1430   Array<jushort>* inner_class_list = inner_classes();
  1431   if (inner_class_list == NULL) {
  1432     return 0;
  1434   int length = inner_class_list->length();
  1435   if (length % inner_class_next_offset == 0) {
  1436     return 0;
  1437   } else {
  1438     int index = length - enclosing_method_attribute_size;
  1439     assert(offset < enclosing_method_attribute_size, "invalid offset");
  1440     return inner_class_list->at(index + offset);
  1444 void InstanceKlass::set_enclosing_method_indices(u2 class_index,
  1445                                                  u2 method_index) {
  1446   Array<jushort>* inner_class_list = inner_classes();
  1447   assert (inner_class_list != NULL, "_inner_classes list is not set up");
  1448   int length = inner_class_list->length();
  1449   if (length % inner_class_next_offset == enclosing_method_attribute_size) {
  1450     int index = length - enclosing_method_attribute_size;
  1451     inner_class_list->at_put(
  1452       index + enclosing_method_class_index_offset, class_index);
  1453     inner_class_list->at_put(
  1454       index + enclosing_method_method_index_offset, method_index);
  1458 // Lookup or create a jmethodID.
  1459 // This code is called by the VMThread and JavaThreads so the
  1460 // locking has to be done very carefully to avoid deadlocks
  1461 // and/or other cache consistency problems.
  1462 //
  1463 jmethodID InstanceKlass::get_jmethod_id(instanceKlassHandle ik_h, methodHandle method_h) {
  1464   size_t idnum = (size_t)method_h->method_idnum();
  1465   jmethodID* jmeths = ik_h->methods_jmethod_ids_acquire();
  1466   size_t length = 0;
  1467   jmethodID id = NULL;
  1469   // We use a double-check locking idiom here because this cache is
  1470   // performance sensitive. In the normal system, this cache only
  1471   // transitions from NULL to non-NULL which is safe because we use
  1472   // release_set_methods_jmethod_ids() to advertise the new cache.
  1473   // A partially constructed cache should never be seen by a racing
  1474   // thread. We also use release_store_ptr() to save a new jmethodID
  1475   // in the cache so a partially constructed jmethodID should never be
  1476   // seen either. Cache reads of existing jmethodIDs proceed without a
  1477   // lock, but cache writes of a new jmethodID requires uniqueness and
  1478   // creation of the cache itself requires no leaks so a lock is
  1479   // generally acquired in those two cases.
  1480   //
  1481   // If the RedefineClasses() API has been used, then this cache can
  1482   // grow and we'll have transitions from non-NULL to bigger non-NULL.
  1483   // Cache creation requires no leaks and we require safety between all
  1484   // cache accesses and freeing of the old cache so a lock is generally
  1485   // acquired when the RedefineClasses() API has been used.
  1487   if (jmeths != NULL) {
  1488     // the cache already exists
  1489     if (!ik_h->idnum_can_increment()) {
  1490       // the cache can't grow so we can just get the current values
  1491       get_jmethod_id_length_value(jmeths, idnum, &length, &id);
  1492     } else {
  1493       // cache can grow so we have to be more careful
  1494       if (Threads::number_of_threads() == 0 ||
  1495           SafepointSynchronize::is_at_safepoint()) {
  1496         // we're single threaded or at a safepoint - no locking needed
  1497         get_jmethod_id_length_value(jmeths, idnum, &length, &id);
  1498       } else {
  1499         MutexLocker ml(JmethodIdCreation_lock);
  1500         get_jmethod_id_length_value(jmeths, idnum, &length, &id);
  1504   // implied else:
  1505   // we need to allocate a cache so default length and id values are good
  1507   if (jmeths == NULL ||   // no cache yet
  1508       length <= idnum ||  // cache is too short
  1509       id == NULL) {       // cache doesn't contain entry
  1511     // This function can be called by the VMThread so we have to do all
  1512     // things that might block on a safepoint before grabbing the lock.
  1513     // Otherwise, we can deadlock with the VMThread or have a cache
  1514     // consistency issue. These vars keep track of what we might have
  1515     // to free after the lock is dropped.
  1516     jmethodID  to_dealloc_id     = NULL;
  1517     jmethodID* to_dealloc_jmeths = NULL;
  1519     // may not allocate new_jmeths or use it if we allocate it
  1520     jmethodID* new_jmeths = NULL;
  1521     if (length <= idnum) {
  1522       // allocate a new cache that might be used
  1523       size_t size = MAX2(idnum+1, (size_t)ik_h->idnum_allocated_count());
  1524       new_jmeths = NEW_C_HEAP_ARRAY(jmethodID, size+1, mtClass);
  1525       memset(new_jmeths, 0, (size+1)*sizeof(jmethodID));
  1526       // cache size is stored in element[0], other elements offset by one
  1527       new_jmeths[0] = (jmethodID)size;
  1530     // allocate a new jmethodID that might be used
  1531     jmethodID new_id = NULL;
  1532     if (method_h->is_old() && !method_h->is_obsolete()) {
  1533       // The method passed in is old (but not obsolete), we need to use the current version
  1534       Method* current_method = ik_h->method_with_idnum((int)idnum);
  1535       assert(current_method != NULL, "old and but not obsolete, so should exist");
  1536       new_id = Method::make_jmethod_id(ik_h->class_loader_data(), current_method);
  1537     } else {
  1538       // It is the current version of the method or an obsolete method,
  1539       // use the version passed in
  1540       new_id = Method::make_jmethod_id(ik_h->class_loader_data(), method_h());
  1543     if (Threads::number_of_threads() == 0 ||
  1544         SafepointSynchronize::is_at_safepoint()) {
  1545       // we're single threaded or at a safepoint - no locking needed
  1546       id = get_jmethod_id_fetch_or_update(ik_h, idnum, new_id, new_jmeths,
  1547                                           &to_dealloc_id, &to_dealloc_jmeths);
  1548     } else {
  1549       MutexLocker ml(JmethodIdCreation_lock);
  1550       id = get_jmethod_id_fetch_or_update(ik_h, idnum, new_id, new_jmeths,
  1551                                           &to_dealloc_id, &to_dealloc_jmeths);
  1554     // The lock has been dropped so we can free resources.
  1555     // Free up either the old cache or the new cache if we allocated one.
  1556     if (to_dealloc_jmeths != NULL) {
  1557       FreeHeap(to_dealloc_jmeths);
  1559     // free up the new ID since it wasn't needed
  1560     if (to_dealloc_id != NULL) {
  1561       Method::destroy_jmethod_id(ik_h->class_loader_data(), to_dealloc_id);
  1564   return id;
  1568 // Common code to fetch the jmethodID from the cache or update the
  1569 // cache with the new jmethodID. This function should never do anything
  1570 // that causes the caller to go to a safepoint or we can deadlock with
  1571 // the VMThread or have cache consistency issues.
  1572 //
  1573 jmethodID InstanceKlass::get_jmethod_id_fetch_or_update(
  1574             instanceKlassHandle ik_h, size_t idnum, jmethodID new_id,
  1575             jmethodID* new_jmeths, jmethodID* to_dealloc_id_p,
  1576             jmethodID** to_dealloc_jmeths_p) {
  1577   assert(new_id != NULL, "sanity check");
  1578   assert(to_dealloc_id_p != NULL, "sanity check");
  1579   assert(to_dealloc_jmeths_p != NULL, "sanity check");
  1580   assert(Threads::number_of_threads() == 0 ||
  1581          SafepointSynchronize::is_at_safepoint() ||
  1582          JmethodIdCreation_lock->owned_by_self(), "sanity check");
  1584   // reacquire the cache - we are locked, single threaded or at a safepoint
  1585   jmethodID* jmeths = ik_h->methods_jmethod_ids_acquire();
  1586   jmethodID  id     = NULL;
  1587   size_t     length = 0;
  1589   if (jmeths == NULL ||                         // no cache yet
  1590       (length = (size_t)jmeths[0]) <= idnum) {  // cache is too short
  1591     if (jmeths != NULL) {
  1592       // copy any existing entries from the old cache
  1593       for (size_t index = 0; index < length; index++) {
  1594         new_jmeths[index+1] = jmeths[index+1];
  1596       *to_dealloc_jmeths_p = jmeths;  // save old cache for later delete
  1598     ik_h->release_set_methods_jmethod_ids(jmeths = new_jmeths);
  1599   } else {
  1600     // fetch jmethodID (if any) from the existing cache
  1601     id = jmeths[idnum+1];
  1602     *to_dealloc_jmeths_p = new_jmeths;  // save new cache for later delete
  1604   if (id == NULL) {
  1605     // No matching jmethodID in the existing cache or we have a new
  1606     // cache or we just grew the cache. This cache write is done here
  1607     // by the first thread to win the foot race because a jmethodID
  1608     // needs to be unique once it is generally available.
  1609     id = new_id;
  1611     // The jmethodID cache can be read while unlocked so we have to
  1612     // make sure the new jmethodID is complete before installing it
  1613     // in the cache.
  1614     OrderAccess::release_store_ptr(&jmeths[idnum+1], id);
  1615   } else {
  1616     *to_dealloc_id_p = new_id; // save new id for later delete
  1618   return id;
  1622 // Common code to get the jmethodID cache length and the jmethodID
  1623 // value at index idnum if there is one.
  1624 //
  1625 void InstanceKlass::get_jmethod_id_length_value(jmethodID* cache,
  1626        size_t idnum, size_t *length_p, jmethodID* id_p) {
  1627   assert(cache != NULL, "sanity check");
  1628   assert(length_p != NULL, "sanity check");
  1629   assert(id_p != NULL, "sanity check");
  1631   // cache size is stored in element[0], other elements offset by one
  1632   *length_p = (size_t)cache[0];
  1633   if (*length_p <= idnum) {  // cache is too short
  1634     *id_p = NULL;
  1635   } else {
  1636     *id_p = cache[idnum+1];  // fetch jmethodID (if any)
  1641 // Lookup a jmethodID, NULL if not found.  Do no blocking, no allocations, no handles
  1642 jmethodID InstanceKlass::jmethod_id_or_null(Method* method) {
  1643   size_t idnum = (size_t)method->method_idnum();
  1644   jmethodID* jmeths = methods_jmethod_ids_acquire();
  1645   size_t length;                                // length assigned as debugging crumb
  1646   jmethodID id = NULL;
  1647   if (jmeths != NULL &&                         // If there is a cache
  1648       (length = (size_t)jmeths[0]) > idnum) {   // and if it is long enough,
  1649     id = jmeths[idnum+1];                       // Look up the id (may be NULL)
  1651   return id;
  1655 // Cache an itable index
  1656 void InstanceKlass::set_cached_itable_index(size_t idnum, int index) {
  1657   int* indices = methods_cached_itable_indices_acquire();
  1658   int* to_dealloc_indices = NULL;
  1660   // We use a double-check locking idiom here because this cache is
  1661   // performance sensitive. In the normal system, this cache only
  1662   // transitions from NULL to non-NULL which is safe because we use
  1663   // release_set_methods_cached_itable_indices() to advertise the
  1664   // new cache. A partially constructed cache should never be seen
  1665   // by a racing thread. Cache reads and writes proceed without a
  1666   // lock, but creation of the cache itself requires no leaks so a
  1667   // lock is generally acquired in that case.
  1668   //
  1669   // If the RedefineClasses() API has been used, then this cache can
  1670   // grow and we'll have transitions from non-NULL to bigger non-NULL.
  1671   // Cache creation requires no leaks and we require safety between all
  1672   // cache accesses and freeing of the old cache so a lock is generally
  1673   // acquired when the RedefineClasses() API has been used.
  1675   if (indices == NULL || idnum_can_increment()) {
  1676     // we need a cache or the cache can grow
  1677     MutexLocker ml(JNICachedItableIndex_lock);
  1678     // reacquire the cache to see if another thread already did the work
  1679     indices = methods_cached_itable_indices_acquire();
  1680     size_t length = 0;
  1681     // cache size is stored in element[0], other elements offset by one
  1682     if (indices == NULL || (length = (size_t)indices[0]) <= idnum) {
  1683       size_t size = MAX2(idnum+1, (size_t)idnum_allocated_count());
  1684       int* new_indices = NEW_C_HEAP_ARRAY(int, size+1, mtClass);
  1685       new_indices[0] = (int)size;
  1686       // copy any existing entries
  1687       size_t i;
  1688       for (i = 0; i < length; i++) {
  1689         new_indices[i+1] = indices[i+1];
  1691       // Set all the rest to -1
  1692       for (i = length; i < size; i++) {
  1693         new_indices[i+1] = -1;
  1695       if (indices != NULL) {
  1696         // We have an old cache to delete so save it for after we
  1697         // drop the lock.
  1698         to_dealloc_indices = indices;
  1700       release_set_methods_cached_itable_indices(indices = new_indices);
  1703     if (idnum_can_increment()) {
  1704       // this cache can grow so we have to write to it safely
  1705       indices[idnum+1] = index;
  1707   } else {
  1708     CHECK_UNHANDLED_OOPS_ONLY(Thread::current()->clear_unhandled_oops());
  1711   if (!idnum_can_increment()) {
  1712     // The cache cannot grow and this JNI itable index value does not
  1713     // have to be unique like a jmethodID. If there is a race to set it,
  1714     // it doesn't matter.
  1715     indices[idnum+1] = index;
  1718   if (to_dealloc_indices != NULL) {
  1719     // we allocated a new cache so free the old one
  1720     FreeHeap(to_dealloc_indices);
  1725 // Retrieve a cached itable index
  1726 int InstanceKlass::cached_itable_index(size_t idnum) {
  1727   int* indices = methods_cached_itable_indices_acquire();
  1728   if (indices != NULL && ((size_t)indices[0]) > idnum) {
  1729      // indices exist and are long enough, retrieve possible cached
  1730     return indices[idnum+1];
  1732   return -1;
  1736 //
  1737 // Walk the list of dependent nmethods searching for nmethods which
  1738 // are dependent on the changes that were passed in and mark them for
  1739 // deoptimization.  Returns the number of nmethods found.
  1740 //
  1741 int InstanceKlass::mark_dependent_nmethods(DepChange& changes) {
  1742   assert_locked_or_safepoint(CodeCache_lock);
  1743   int found = 0;
  1744   nmethodBucket* b = _dependencies;
  1745   while (b != NULL) {
  1746     nmethod* nm = b->get_nmethod();
  1747     // since dependencies aren't removed until an nmethod becomes a zombie,
  1748     // the dependency list may contain nmethods which aren't alive.
  1749     if (nm->is_alive() && !nm->is_marked_for_deoptimization() && nm->check_dependency_on(changes)) {
  1750       if (TraceDependencies) {
  1751         ResourceMark rm;
  1752         tty->print_cr("Marked for deoptimization");
  1753         tty->print_cr("  context = %s", this->external_name());
  1754         changes.print();
  1755         nm->print();
  1756         nm->print_dependencies();
  1758       nm->mark_for_deoptimization();
  1759       found++;
  1761     b = b->next();
  1763   return found;
  1767 //
  1768 // Add an nmethodBucket to the list of dependencies for this nmethod.
  1769 // It's possible that an nmethod has multiple dependencies on this klass
  1770 // so a count is kept for each bucket to guarantee that creation and
  1771 // deletion of dependencies is consistent.
  1772 //
  1773 void InstanceKlass::add_dependent_nmethod(nmethod* nm) {
  1774   assert_locked_or_safepoint(CodeCache_lock);
  1775   nmethodBucket* b = _dependencies;
  1776   nmethodBucket* last = NULL;
  1777   while (b != NULL) {
  1778     if (nm == b->get_nmethod()) {
  1779       b->increment();
  1780       return;
  1782     b = b->next();
  1784   _dependencies = new nmethodBucket(nm, _dependencies);
  1788 //
  1789 // Decrement count of the nmethod in the dependency list and remove
  1790 // the bucket competely when the count goes to 0.  This method must
  1791 // find a corresponding bucket otherwise there's a bug in the
  1792 // recording of dependecies.
  1793 //
  1794 void InstanceKlass::remove_dependent_nmethod(nmethod* nm) {
  1795   assert_locked_or_safepoint(CodeCache_lock);
  1796   nmethodBucket* b = _dependencies;
  1797   nmethodBucket* last = NULL;
  1798   while (b != NULL) {
  1799     if (nm == b->get_nmethod()) {
  1800       if (b->decrement() == 0) {
  1801         if (last == NULL) {
  1802           _dependencies = b->next();
  1803         } else {
  1804           last->set_next(b->next());
  1806         delete b;
  1808       return;
  1810     last = b;
  1811     b = b->next();
  1813 #ifdef ASSERT
  1814   tty->print_cr("### %s can't find dependent nmethod:", this->external_name());
  1815   nm->print();
  1816 #endif // ASSERT
  1817   ShouldNotReachHere();
  1821 #ifndef PRODUCT
  1822 void InstanceKlass::print_dependent_nmethods(bool verbose) {
  1823   nmethodBucket* b = _dependencies;
  1824   int idx = 0;
  1825   while (b != NULL) {
  1826     nmethod* nm = b->get_nmethod();
  1827     tty->print("[%d] count=%d { ", idx++, b->count());
  1828     if (!verbose) {
  1829       nm->print_on(tty, "nmethod");
  1830       tty->print_cr(" } ");
  1831     } else {
  1832       nm->print();
  1833       nm->print_dependencies();
  1834       tty->print_cr("--- } ");
  1836     b = b->next();
  1841 bool InstanceKlass::is_dependent_nmethod(nmethod* nm) {
  1842   nmethodBucket* b = _dependencies;
  1843   while (b != NULL) {
  1844     if (nm == b->get_nmethod()) {
  1845       return true;
  1847     b = b->next();
  1849   return false;
  1851 #endif //PRODUCT
  1854 // Garbage collection
  1856 void InstanceKlass::oops_do(OopClosure* cl) {
  1857   Klass::oops_do(cl);
  1859   cl->do_oop(adr_protection_domain());
  1860   cl->do_oop(adr_signers());
  1861   cl->do_oop(adr_init_lock());
  1863   // Don't walk the arrays since they are walked from the ClassLoaderData objects.
  1866 #ifdef ASSERT
  1867 template <class T> void assert_is_in(T *p) {
  1868   T heap_oop = oopDesc::load_heap_oop(p);
  1869   if (!oopDesc::is_null(heap_oop)) {
  1870     oop o = oopDesc::decode_heap_oop_not_null(heap_oop);
  1871     assert(Universe::heap()->is_in(o), "should be in heap");
  1874 template <class T> void assert_is_in_closed_subset(T *p) {
  1875   T heap_oop = oopDesc::load_heap_oop(p);
  1876   if (!oopDesc::is_null(heap_oop)) {
  1877     oop o = oopDesc::decode_heap_oop_not_null(heap_oop);
  1878     assert(Universe::heap()->is_in_closed_subset(o),
  1879            err_msg("should be in closed *p " INTPTR_FORMAT " " INTPTR_FORMAT, (address)p, (address)o));
  1882 template <class T> void assert_is_in_reserved(T *p) {
  1883   T heap_oop = oopDesc::load_heap_oop(p);
  1884   if (!oopDesc::is_null(heap_oop)) {
  1885     oop o = oopDesc::decode_heap_oop_not_null(heap_oop);
  1886     assert(Universe::heap()->is_in_reserved(o), "should be in reserved");
  1889 template <class T> void assert_nothing(T *p) {}
  1891 #else
  1892 template <class T> void assert_is_in(T *p) {}
  1893 template <class T> void assert_is_in_closed_subset(T *p) {}
  1894 template <class T> void assert_is_in_reserved(T *p) {}
  1895 template <class T> void assert_nothing(T *p) {}
  1896 #endif // ASSERT
  1898 //
  1899 // Macros that iterate over areas of oops which are specialized on type of
  1900 // oop pointer either narrow or wide, depending on UseCompressedOops
  1901 //
  1902 // Parameters are:
  1903 //   T         - type of oop to point to (either oop or narrowOop)
  1904 //   start_p   - starting pointer for region to iterate over
  1905 //   count     - number of oops or narrowOops to iterate over
  1906 //   do_oop    - action to perform on each oop (it's arbitrary C code which
  1907 //               makes it more efficient to put in a macro rather than making
  1908 //               it a template function)
  1909 //   assert_fn - assert function which is template function because performance
  1910 //               doesn't matter when enabled.
  1911 #define InstanceKlass_SPECIALIZED_OOP_ITERATE( \
  1912   T, start_p, count, do_oop,                \
  1913   assert_fn)                                \
  1914 {                                           \
  1915   T* p         = (T*)(start_p);             \
  1916   T* const end = p + (count);               \
  1917   while (p < end) {                         \
  1918     (assert_fn)(p);                         \
  1919     do_oop;                                 \
  1920     ++p;                                    \
  1921   }                                         \
  1924 #define InstanceKlass_SPECIALIZED_OOP_REVERSE_ITERATE( \
  1925   T, start_p, count, do_oop,                \
  1926   assert_fn)                                \
  1927 {                                           \
  1928   T* const start = (T*)(start_p);           \
  1929   T*       p     = start + (count);         \
  1930   while (start < p) {                       \
  1931     --p;                                    \
  1932     (assert_fn)(p);                         \
  1933     do_oop;                                 \
  1934   }                                         \
  1937 #define InstanceKlass_SPECIALIZED_BOUNDED_OOP_ITERATE( \
  1938   T, start_p, count, low, high,             \
  1939   do_oop, assert_fn)                        \
  1940 {                                           \
  1941   T* const l = (T*)(low);                   \
  1942   T* const h = (T*)(high);                  \
  1943   assert(mask_bits((intptr_t)l, sizeof(T)-1) == 0 && \
  1944          mask_bits((intptr_t)h, sizeof(T)-1) == 0,   \
  1945          "bounded region must be properly aligned"); \
  1946   T* p       = (T*)(start_p);               \
  1947   T* end     = p + (count);                 \
  1948   if (p < l) p = l;                         \
  1949   if (end > h) end = h;                     \
  1950   while (p < end) {                         \
  1951     (assert_fn)(p);                         \
  1952     do_oop;                                 \
  1953     ++p;                                    \
  1954   }                                         \
  1958 // The following macros call specialized macros, passing either oop or
  1959 // narrowOop as the specialization type.  These test the UseCompressedOops
  1960 // flag.
  1961 #define InstanceKlass_OOP_MAP_ITERATE(obj, do_oop, assert_fn)            \
  1962 {                                                                        \
  1963   /* Compute oopmap block range. The common case                         \
  1964      is nonstatic_oop_map_size == 1. */                                  \
  1965   OopMapBlock* map           = start_of_nonstatic_oop_maps();            \
  1966   OopMapBlock* const end_map = map + nonstatic_oop_map_count();          \
  1967   if (UseCompressedOops) {                                               \
  1968     while (map < end_map) {                                              \
  1969       InstanceKlass_SPECIALIZED_OOP_ITERATE(narrowOop,                   \
  1970         obj->obj_field_addr<narrowOop>(map->offset()), map->count(),     \
  1971         do_oop, assert_fn)                                               \
  1972       ++map;                                                             \
  1973     }                                                                    \
  1974   } else {                                                               \
  1975     while (map < end_map) {                                              \
  1976       InstanceKlass_SPECIALIZED_OOP_ITERATE(oop,                         \
  1977         obj->obj_field_addr<oop>(map->offset()), map->count(),           \
  1978         do_oop, assert_fn)                                               \
  1979       ++map;                                                             \
  1980     }                                                                    \
  1981   }                                                                      \
  1984 #define InstanceKlass_OOP_MAP_REVERSE_ITERATE(obj, do_oop, assert_fn)    \
  1985 {                                                                        \
  1986   OopMapBlock* const start_map = start_of_nonstatic_oop_maps();          \
  1987   OopMapBlock* map             = start_map + nonstatic_oop_map_count();  \
  1988   if (UseCompressedOops) {                                               \
  1989     while (start_map < map) {                                            \
  1990       --map;                                                             \
  1991       InstanceKlass_SPECIALIZED_OOP_REVERSE_ITERATE(narrowOop,           \
  1992         obj->obj_field_addr<narrowOop>(map->offset()), map->count(),     \
  1993         do_oop, assert_fn)                                               \
  1994     }                                                                    \
  1995   } else {                                                               \
  1996     while (start_map < map) {                                            \
  1997       --map;                                                             \
  1998       InstanceKlass_SPECIALIZED_OOP_REVERSE_ITERATE(oop,                 \
  1999         obj->obj_field_addr<oop>(map->offset()), map->count(),           \
  2000         do_oop, assert_fn)                                               \
  2001     }                                                                    \
  2002   }                                                                      \
  2005 #define InstanceKlass_BOUNDED_OOP_MAP_ITERATE(obj, low, high, do_oop,    \
  2006                                               assert_fn)                 \
  2007 {                                                                        \
  2008   /* Compute oopmap block range. The common case is                      \
  2009      nonstatic_oop_map_size == 1, so we accept the                       \
  2010      usually non-existent extra overhead of examining                    \
  2011      all the maps. */                                                    \
  2012   OopMapBlock* map           = start_of_nonstatic_oop_maps();            \
  2013   OopMapBlock* const end_map = map + nonstatic_oop_map_count();          \
  2014   if (UseCompressedOops) {                                               \
  2015     while (map < end_map) {                                              \
  2016       InstanceKlass_SPECIALIZED_BOUNDED_OOP_ITERATE(narrowOop,           \
  2017         obj->obj_field_addr<narrowOop>(map->offset()), map->count(),     \
  2018         low, high,                                                       \
  2019         do_oop, assert_fn)                                               \
  2020       ++map;                                                             \
  2021     }                                                                    \
  2022   } else {                                                               \
  2023     while (map < end_map) {                                              \
  2024       InstanceKlass_SPECIALIZED_BOUNDED_OOP_ITERATE(oop,                 \
  2025         obj->obj_field_addr<oop>(map->offset()), map->count(),           \
  2026         low, high,                                                       \
  2027         do_oop, assert_fn)                                               \
  2028       ++map;                                                             \
  2029     }                                                                    \
  2030   }                                                                      \
  2033 void InstanceKlass::oop_follow_contents(oop obj) {
  2034   assert(obj != NULL, "can't follow the content of NULL object");
  2035   MarkSweep::follow_klass(obj->klass());
  2036   InstanceKlass_OOP_MAP_ITERATE( \
  2037     obj, \
  2038     MarkSweep::mark_and_push(p), \
  2039     assert_is_in_closed_subset)
  2042 #ifndef SERIALGC
  2043 void InstanceKlass::oop_follow_contents(ParCompactionManager* cm,
  2044                                         oop obj) {
  2045   assert(obj != NULL, "can't follow the content of NULL object");
  2046   PSParallelCompact::follow_klass(cm, obj->klass());
  2047   // Only mark the header and let the scan of the meta-data mark
  2048   // everything else.
  2049   InstanceKlass_OOP_MAP_ITERATE( \
  2050     obj, \
  2051     PSParallelCompact::mark_and_push(cm, p), \
  2052     assert_is_in)
  2054 #endif // SERIALGC
  2056 // closure's do_metadata() method dictates whether the given closure should be
  2057 // applied to the klass ptr in the object header.
  2059 #define if_do_metadata_checked(closure, nv_suffix)                    \
  2060   /* Make sure the non-virtual and the virtual versions match. */     \
  2061   assert(closure->do_metadata##nv_suffix() == closure->do_metadata(), \
  2062       "Inconsistency in do_metadata");                                \
  2063   if (closure->do_metadata##nv_suffix())
  2065 #define InstanceKlass_OOP_OOP_ITERATE_DEFN(OopClosureType, nv_suffix)        \
  2067 int InstanceKlass::oop_oop_iterate##nv_suffix(oop obj, OopClosureType* closure) { \
  2068   SpecializationStats::record_iterate_call##nv_suffix(SpecializationStats::ik);\
  2069   /* header */                                                          \
  2070   if_do_metadata_checked(closure, nv_suffix) {                          \
  2071     closure->do_klass##nv_suffix(obj->klass());                         \
  2072   }                                                                     \
  2073   InstanceKlass_OOP_MAP_ITERATE(                                        \
  2074     obj,                                                                \
  2075     SpecializationStats::                                               \
  2076       record_do_oop_call##nv_suffix(SpecializationStats::ik);           \
  2077     (closure)->do_oop##nv_suffix(p),                                    \
  2078     assert_is_in_closed_subset)                                         \
  2079   return size_helper();                                                 \
  2082 #ifndef SERIALGC
  2083 #define InstanceKlass_OOP_OOP_ITERATE_BACKWARDS_DEFN(OopClosureType, nv_suffix) \
  2085 int InstanceKlass::oop_oop_iterate_backwards##nv_suffix(oop obj,                \
  2086                                               OopClosureType* closure) {        \
  2087   SpecializationStats::record_iterate_call##nv_suffix(SpecializationStats::ik); \
  2088   /* header */                                                                  \
  2089   if_do_metadata_checked(closure, nv_suffix) {                                  \
  2090     closure->do_klass##nv_suffix(obj->klass());                                 \
  2091   }                                                                             \
  2092   /* instance variables */                                                      \
  2093   InstanceKlass_OOP_MAP_REVERSE_ITERATE(                                        \
  2094     obj,                                                                        \
  2095     SpecializationStats::record_do_oop_call##nv_suffix(SpecializationStats::ik);\
  2096     (closure)->do_oop##nv_suffix(p),                                            \
  2097     assert_is_in_closed_subset)                                                 \
  2098    return size_helper();                                                        \
  2100 #endif // !SERIALGC
  2102 #define InstanceKlass_OOP_OOP_ITERATE_DEFN_m(OopClosureType, nv_suffix) \
  2104 int InstanceKlass::oop_oop_iterate##nv_suffix##_m(oop obj,              \
  2105                                                   OopClosureType* closure, \
  2106                                                   MemRegion mr) {          \
  2107   SpecializationStats::record_iterate_call##nv_suffix(SpecializationStats::ik);\
  2108   if_do_metadata_checked(closure, nv_suffix) {                           \
  2109     if (mr.contains(obj)) {                                              \
  2110       closure->do_klass##nv_suffix(obj->klass());                        \
  2111     }                                                                    \
  2112   }                                                                      \
  2113   InstanceKlass_BOUNDED_OOP_MAP_ITERATE(                                 \
  2114     obj, mr.start(), mr.end(),                                           \
  2115     (closure)->do_oop##nv_suffix(p),                                     \
  2116     assert_is_in_closed_subset)                                          \
  2117   return size_helper();                                                  \
  2120 ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceKlass_OOP_OOP_ITERATE_DEFN)
  2121 ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceKlass_OOP_OOP_ITERATE_DEFN)
  2122 ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceKlass_OOP_OOP_ITERATE_DEFN_m)
  2123 ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceKlass_OOP_OOP_ITERATE_DEFN_m)
  2124 #ifndef SERIALGC
  2125 ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceKlass_OOP_OOP_ITERATE_BACKWARDS_DEFN)
  2126 ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceKlass_OOP_OOP_ITERATE_BACKWARDS_DEFN)
  2127 #endif // !SERIALGC
  2129 int InstanceKlass::oop_adjust_pointers(oop obj) {
  2130   int size = size_helper();
  2131   InstanceKlass_OOP_MAP_ITERATE( \
  2132     obj, \
  2133     MarkSweep::adjust_pointer(p), \
  2134     assert_is_in)
  2135   MarkSweep::adjust_klass(obj->klass());
  2136   return size;
  2139 #ifndef SERIALGC
  2140 void InstanceKlass::oop_push_contents(PSPromotionManager* pm, oop obj) {
  2141   InstanceKlass_OOP_MAP_REVERSE_ITERATE( \
  2142     obj, \
  2143     if (PSScavenge::should_scavenge(p)) { \
  2144       pm->claim_or_forward_depth(p); \
  2145     }, \
  2146     assert_nothing )
  2149 int InstanceKlass::oop_update_pointers(ParCompactionManager* cm, oop obj) {
  2150   int size = size_helper();
  2151   InstanceKlass_OOP_MAP_ITERATE( \
  2152     obj, \
  2153     PSParallelCompact::adjust_pointer(p), \
  2154     assert_is_in)
  2155   obj->update_header(cm);
  2156   return size;
  2159 #endif // SERIALGC
  2161 void InstanceKlass::clean_implementors_list(BoolObjectClosure* is_alive) {
  2162   assert(is_loader_alive(is_alive), "this klass should be live");
  2163   if (is_interface()) {
  2164     if (ClassUnloading) {
  2165       Klass* impl = implementor();
  2166       if (impl != NULL) {
  2167         if (!impl->is_loader_alive(is_alive)) {
  2168           // remove this guy
  2169           *adr_implementor() = NULL;
  2176 void InstanceKlass::clean_method_data(BoolObjectClosure* is_alive) {
  2177 #ifdef COMPILER2
  2178   // Currently only used by C2.
  2179   for (int m = 0; m < methods()->length(); m++) {
  2180     MethodData* mdo = methods()->at(m)->method_data();
  2181     if (mdo != NULL) {
  2182       for (ProfileData* data = mdo->first_data();
  2183            mdo->is_valid(data);
  2184            data = mdo->next_data(data)) {
  2185         data->clean_weak_klass_links(is_alive);
  2189 #else
  2190 #ifdef ASSERT
  2191   // Verify that we haven't started to use MDOs for C1.
  2192   for (int m = 0; m < methods()->length(); m++) {
  2193     MethodData* mdo = methods()->at(m)->method_data();
  2194     assert(mdo == NULL, "Didn't expect C1 to use MDOs");
  2196 #endif // ASSERT
  2197 #endif // !COMPILER2
  2201 static void remove_unshareable_in_class(Klass* k) {
  2202   // remove klass's unshareable info
  2203   k->remove_unshareable_info();
  2206 void InstanceKlass::remove_unshareable_info() {
  2207   Klass::remove_unshareable_info();
  2208   // Unlink the class
  2209   if (is_linked()) {
  2210     unlink_class();
  2212   init_implementor();
  2214   constants()->remove_unshareable_info();
  2216   for (int i = 0; i < methods()->length(); i++) {
  2217     Method* m = methods()->at(i);
  2218     m->remove_unshareable_info();
  2221   // Need to reinstate when reading back the class.
  2222   set_init_lock(NULL);
  2224   // do array classes also.
  2225   array_klasses_do(remove_unshareable_in_class);
  2228 void restore_unshareable_in_class(Klass* k, TRAPS) {
  2229   k->restore_unshareable_info(CHECK);
  2232 void InstanceKlass::restore_unshareable_info(TRAPS) {
  2233   Klass::restore_unshareable_info(CHECK);
  2234   instanceKlassHandle ik(THREAD, this);
  2236   Array<Method*>* methods = ik->methods();
  2237   int num_methods = methods->length();
  2238   for (int index2 = 0; index2 < num_methods; ++index2) {
  2239     methodHandle m(THREAD, methods->at(index2));
  2240     m()->link_method(m, CHECK);
  2241     // restore method's vtable by calling a virtual function
  2242     m->restore_vtable();
  2244   if (JvmtiExport::has_redefined_a_class()) {
  2245     // Reinitialize vtable because RedefineClasses may have changed some
  2246     // entries in this vtable for super classes so the CDS vtable might
  2247     // point to old or obsolete entries.  RedefineClasses doesn't fix up
  2248     // vtables in the shared system dictionary, only the main one.
  2249     // It also redefines the itable too so fix that too.
  2250     ResourceMark rm(THREAD);
  2251     ik->vtable()->initialize_vtable(false, CHECK);
  2252     ik->itable()->initialize_itable(false, CHECK);
  2255   // Allocate a simple java object for a lock.
  2256   // This needs to be a java object because during class initialization
  2257   // it can be held across a java call.
  2258   typeArrayOop r = oopFactory::new_typeArray(T_INT, 0, CHECK);
  2259   Handle h(THREAD, (oop)r);
  2260   ik->set_init_lock(h());
  2262   // restore constant pool resolved references
  2263   ik->constants()->restore_unshareable_info(CHECK);
  2265   ik->array_klasses_do(restore_unshareable_in_class, CHECK);
  2268 static void clear_all_breakpoints(Method* m) {
  2269   m->clear_all_breakpoints();
  2272 void InstanceKlass::release_C_heap_structures() {
  2273   // Deallocate oop map cache
  2274   if (_oop_map_cache != NULL) {
  2275     delete _oop_map_cache;
  2276     _oop_map_cache = NULL;
  2279   // Deallocate JNI identifiers for jfieldIDs
  2280   JNIid::deallocate(jni_ids());
  2281   set_jni_ids(NULL);
  2283   jmethodID* jmeths = methods_jmethod_ids_acquire();
  2284   if (jmeths != (jmethodID*)NULL) {
  2285     release_set_methods_jmethod_ids(NULL);
  2286     FreeHeap(jmeths);
  2289   int* indices = methods_cached_itable_indices_acquire();
  2290   if (indices != (int*)NULL) {
  2291     release_set_methods_cached_itable_indices(NULL);
  2292     FreeHeap(indices);
  2295   // release dependencies
  2296   nmethodBucket* b = _dependencies;
  2297   _dependencies = NULL;
  2298   while (b != NULL) {
  2299     nmethodBucket* next = b->next();
  2300     delete b;
  2301     b = next;
  2304   // Deallocate breakpoint records
  2305   if (breakpoints() != 0x0) {
  2306     methods_do(clear_all_breakpoints);
  2307     assert(breakpoints() == 0x0, "should have cleared breakpoints");
  2310   // deallocate information about previous versions
  2311   if (_previous_versions != NULL) {
  2312     for (int i = _previous_versions->length() - 1; i >= 0; i--) {
  2313       PreviousVersionNode * pv_node = _previous_versions->at(i);
  2314       delete pv_node;
  2316     delete _previous_versions;
  2317     _previous_versions = NULL;
  2320   // deallocate the cached class file
  2321   if (_cached_class_file_bytes != NULL) {
  2322     os::free(_cached_class_file_bytes, mtClass);
  2323     _cached_class_file_bytes = NULL;
  2324     _cached_class_file_len = 0;
  2327   // Decrement symbol reference counts associated with the unloaded class.
  2328   if (_name != NULL) _name->decrement_refcount();
  2329   // unreference array name derived from this class name (arrays of an unloaded
  2330   // class can't be referenced anymore).
  2331   if (_array_name != NULL)  _array_name->decrement_refcount();
  2332   if (_source_file_name != NULL) _source_file_name->decrement_refcount();
  2333   if (_source_debug_extension != NULL) FREE_C_HEAP_ARRAY(char, _source_debug_extension, mtClass);
  2336 void InstanceKlass::set_source_file_name(Symbol* n) {
  2337   _source_file_name = n;
  2338   if (_source_file_name != NULL) _source_file_name->increment_refcount();
  2341 void InstanceKlass::set_source_debug_extension(char* array, int length) {
  2342   if (array == NULL) {
  2343     _source_debug_extension = NULL;
  2344   } else {
  2345     // Adding one to the attribute length in order to store a null terminator
  2346     // character could cause an overflow because the attribute length is
  2347     // already coded with an u4 in the classfile, but in practice, it's
  2348     // unlikely to happen.
  2349     assert((length+1) > length, "Overflow checking");
  2350     char* sde = NEW_C_HEAP_ARRAY(char, (length + 1), mtClass);
  2351     for (int i = 0; i < length; i++) {
  2352       sde[i] = array[i];
  2354     sde[length] = '\0';
  2355     _source_debug_extension = sde;
  2359 address InstanceKlass::static_field_addr(int offset) {
  2360   return (address)(offset + InstanceMirrorKlass::offset_of_static_fields() + (intptr_t)java_mirror());
  2364 const char* InstanceKlass::signature_name() const {
  2365   const char* src = (const char*) (name()->as_C_string());
  2366   const int src_length = (int)strlen(src);
  2367   char* dest = NEW_RESOURCE_ARRAY(char, src_length + 3);
  2368   int src_index = 0;
  2369   int dest_index = 0;
  2370   dest[dest_index++] = 'L';
  2371   while (src_index < src_length) {
  2372     dest[dest_index++] = src[src_index++];
  2374   dest[dest_index++] = ';';
  2375   dest[dest_index] = '\0';
  2376   return dest;
  2379 // different verisons of is_same_class_package
  2380 bool InstanceKlass::is_same_class_package(Klass* class2) {
  2381   Klass* class1 = this;
  2382   oop classloader1 = InstanceKlass::cast(class1)->class_loader();
  2383   Symbol* classname1 = class1->name();
  2385   if (class2->oop_is_objArray()) {
  2386     class2 = ObjArrayKlass::cast(class2)->bottom_klass();
  2388   oop classloader2;
  2389   if (class2->oop_is_instance()) {
  2390     classloader2 = InstanceKlass::cast(class2)->class_loader();
  2391   } else {
  2392     assert(class2->oop_is_typeArray(), "should be type array");
  2393     classloader2 = NULL;
  2395   Symbol* classname2 = class2->name();
  2397   return InstanceKlass::is_same_class_package(classloader1, classname1,
  2398                                               classloader2, classname2);
  2401 bool InstanceKlass::is_same_class_package(oop classloader2, Symbol* classname2) {
  2402   Klass* class1 = this;
  2403   oop classloader1 = InstanceKlass::cast(class1)->class_loader();
  2404   Symbol* classname1 = class1->name();
  2406   return InstanceKlass::is_same_class_package(classloader1, classname1,
  2407                                               classloader2, classname2);
  2410 // return true if two classes are in the same package, classloader
  2411 // and classname information is enough to determine a class's package
  2412 bool InstanceKlass::is_same_class_package(oop class_loader1, Symbol* class_name1,
  2413                                           oop class_loader2, Symbol* class_name2) {
  2414   if (class_loader1 != class_loader2) {
  2415     return false;
  2416   } else if (class_name1 == class_name2) {
  2417     return true;                // skip painful bytewise comparison
  2418   } else {
  2419     ResourceMark rm;
  2421     // The Symbol*'s are in UTF8 encoding. Since we only need to check explicitly
  2422     // for ASCII characters ('/', 'L', '['), we can keep them in UTF8 encoding.
  2423     // Otherwise, we just compare jbyte values between the strings.
  2424     const jbyte *name1 = class_name1->base();
  2425     const jbyte *name2 = class_name2->base();
  2427     const jbyte *last_slash1 = UTF8::strrchr(name1, class_name1->utf8_length(), '/');
  2428     const jbyte *last_slash2 = UTF8::strrchr(name2, class_name2->utf8_length(), '/');
  2430     if ((last_slash1 == NULL) || (last_slash2 == NULL)) {
  2431       // One of the two doesn't have a package.  Only return true
  2432       // if the other one also doesn't have a package.
  2433       return last_slash1 == last_slash2;
  2434     } else {
  2435       // Skip over '['s
  2436       if (*name1 == '[') {
  2437         do {
  2438           name1++;
  2439         } while (*name1 == '[');
  2440         if (*name1 != 'L') {
  2441           // Something is terribly wrong.  Shouldn't be here.
  2442           return false;
  2445       if (*name2 == '[') {
  2446         do {
  2447           name2++;
  2448         } while (*name2 == '[');
  2449         if (*name2 != 'L') {
  2450           // Something is terribly wrong.  Shouldn't be here.
  2451           return false;
  2455       // Check that package part is identical
  2456       int length1 = last_slash1 - name1;
  2457       int length2 = last_slash2 - name2;
  2459       return UTF8::equal(name1, length1, name2, length2);
  2464 // Returns true iff super_method can be overridden by a method in targetclassname
  2465 // See JSL 3rd edition 8.4.6.1
  2466 // Assumes name-signature match
  2467 // "this" is InstanceKlass of super_method which must exist
  2468 // note that the InstanceKlass of the method in the targetclassname has not always been created yet
  2469 bool InstanceKlass::is_override(methodHandle super_method, Handle targetclassloader, Symbol* targetclassname, TRAPS) {
  2470    // Private methods can not be overridden
  2471    if (super_method->is_private()) {
  2472      return false;
  2474    // If super method is accessible, then override
  2475    if ((super_method->is_protected()) ||
  2476        (super_method->is_public())) {
  2477      return true;
  2479    // Package-private methods are not inherited outside of package
  2480    assert(super_method->is_package_private(), "must be package private");
  2481    return(is_same_class_package(targetclassloader(), targetclassname));
  2484 /* defined for now in jvm.cpp, for historical reasons *--
  2485 Klass* InstanceKlass::compute_enclosing_class_impl(instanceKlassHandle self,
  2486                                                      Symbol*& simple_name_result, TRAPS) {
  2487   ...
  2489 */
  2491 // tell if two classes have the same enclosing class (at package level)
  2492 bool InstanceKlass::is_same_package_member_impl(instanceKlassHandle class1,
  2493                                                 Klass* class2_oop, TRAPS) {
  2494   if (class2_oop == class1())                       return true;
  2495   if (!class2_oop->oop_is_instance())  return false;
  2496   instanceKlassHandle class2(THREAD, class2_oop);
  2498   // must be in same package before we try anything else
  2499   if (!class1->is_same_class_package(class2->class_loader(), class2->name()))
  2500     return false;
  2502   // As long as there is an outer1.getEnclosingClass,
  2503   // shift the search outward.
  2504   instanceKlassHandle outer1 = class1;
  2505   for (;;) {
  2506     // As we walk along, look for equalities between outer1 and class2.
  2507     // Eventually, the walks will terminate as outer1 stops
  2508     // at the top-level class around the original class.
  2509     bool ignore_inner_is_member;
  2510     Klass* next = outer1->compute_enclosing_class(&ignore_inner_is_member,
  2511                                                     CHECK_false);
  2512     if (next == NULL)  break;
  2513     if (next == class2())  return true;
  2514     outer1 = instanceKlassHandle(THREAD, next);
  2517   // Now do the same for class2.
  2518   instanceKlassHandle outer2 = class2;
  2519   for (;;) {
  2520     bool ignore_inner_is_member;
  2521     Klass* next = outer2->compute_enclosing_class(&ignore_inner_is_member,
  2522                                                     CHECK_false);
  2523     if (next == NULL)  break;
  2524     // Might as well check the new outer against all available values.
  2525     if (next == class1())  return true;
  2526     if (next == outer1())  return true;
  2527     outer2 = instanceKlassHandle(THREAD, next);
  2530   // If by this point we have not found an equality between the
  2531   // two classes, we know they are in separate package members.
  2532   return false;
  2536 jint InstanceKlass::compute_modifier_flags(TRAPS) const {
  2537   jint access = access_flags().as_int();
  2539   // But check if it happens to be member class.
  2540   instanceKlassHandle ik(THREAD, this);
  2541   InnerClassesIterator iter(ik);
  2542   for (; !iter.done(); iter.next()) {
  2543     int ioff = iter.inner_class_info_index();
  2544     // Inner class attribute can be zero, skip it.
  2545     // Strange but true:  JVM spec. allows null inner class refs.
  2546     if (ioff == 0) continue;
  2548     // only look at classes that are already loaded
  2549     // since we are looking for the flags for our self.
  2550     Symbol* inner_name = ik->constants()->klass_name_at(ioff);
  2551     if ((ik->name() == inner_name)) {
  2552       // This is really a member class.
  2553       access = iter.inner_access_flags();
  2554       break;
  2557   // Remember to strip ACC_SUPER bit
  2558   return (access & (~JVM_ACC_SUPER)) & JVM_ACC_WRITTEN_FLAGS;
  2561 jint InstanceKlass::jvmti_class_status() const {
  2562   jint result = 0;
  2564   if (is_linked()) {
  2565     result |= JVMTI_CLASS_STATUS_VERIFIED | JVMTI_CLASS_STATUS_PREPARED;
  2568   if (is_initialized()) {
  2569     assert(is_linked(), "Class status is not consistent");
  2570     result |= JVMTI_CLASS_STATUS_INITIALIZED;
  2572   if (is_in_error_state()) {
  2573     result |= JVMTI_CLASS_STATUS_ERROR;
  2575   return result;
  2578 Method* InstanceKlass::method_at_itable(Klass* holder, int index, TRAPS) {
  2579   itableOffsetEntry* ioe = (itableOffsetEntry*)start_of_itable();
  2580   int method_table_offset_in_words = ioe->offset()/wordSize;
  2581   int nof_interfaces = (method_table_offset_in_words - itable_offset_in_words())
  2582                        / itableOffsetEntry::size();
  2584   for (int cnt = 0 ; ; cnt ++, ioe ++) {
  2585     // If the interface isn't implemented by the receiver class,
  2586     // the VM should throw IncompatibleClassChangeError.
  2587     if (cnt >= nof_interfaces) {
  2588       THROW_NULL(vmSymbols::java_lang_IncompatibleClassChangeError());
  2591     Klass* ik = ioe->interface_klass();
  2592     if (ik == holder) break;
  2595   itableMethodEntry* ime = ioe->first_method_entry(this);
  2596   Method* m = ime[index].method();
  2597   if (m == NULL) {
  2598     THROW_NULL(vmSymbols::java_lang_AbstractMethodError());
  2600   return m;
  2603 // On-stack replacement stuff
  2604 void InstanceKlass::add_osr_nmethod(nmethod* n) {
  2605   // only one compilation can be active
  2606   NEEDS_CLEANUP
  2607   // This is a short non-blocking critical region, so the no safepoint check is ok.
  2608   OsrList_lock->lock_without_safepoint_check();
  2609   assert(n->is_osr_method(), "wrong kind of nmethod");
  2610   n->set_osr_link(osr_nmethods_head());
  2611   set_osr_nmethods_head(n);
  2612   // Raise the highest osr level if necessary
  2613   if (TieredCompilation) {
  2614     Method* m = n->method();
  2615     m->set_highest_osr_comp_level(MAX2(m->highest_osr_comp_level(), n->comp_level()));
  2617   // Remember to unlock again
  2618   OsrList_lock->unlock();
  2620   // Get rid of the osr methods for the same bci that have lower levels.
  2621   if (TieredCompilation) {
  2622     for (int l = CompLevel_limited_profile; l < n->comp_level(); l++) {
  2623       nmethod *inv = lookup_osr_nmethod(n->method(), n->osr_entry_bci(), l, true);
  2624       if (inv != NULL && inv->is_in_use()) {
  2625         inv->make_not_entrant();
  2632 void InstanceKlass::remove_osr_nmethod(nmethod* n) {
  2633   // This is a short non-blocking critical region, so the no safepoint check is ok.
  2634   OsrList_lock->lock_without_safepoint_check();
  2635   assert(n->is_osr_method(), "wrong kind of nmethod");
  2636   nmethod* last = NULL;
  2637   nmethod* cur  = osr_nmethods_head();
  2638   int max_level = CompLevel_none;  // Find the max comp level excluding n
  2639   Method* m = n->method();
  2640   // Search for match
  2641   while(cur != NULL && cur != n) {
  2642     if (TieredCompilation) {
  2643       // Find max level before n
  2644       max_level = MAX2(max_level, cur->comp_level());
  2646     last = cur;
  2647     cur = cur->osr_link();
  2649   nmethod* next = NULL;
  2650   if (cur == n) {
  2651     next = cur->osr_link();
  2652     if (last == NULL) {
  2653       // Remove first element
  2654       set_osr_nmethods_head(next);
  2655     } else {
  2656       last->set_osr_link(next);
  2659   n->set_osr_link(NULL);
  2660   if (TieredCompilation) {
  2661     cur = next;
  2662     while (cur != NULL) {
  2663       // Find max level after n
  2664       max_level = MAX2(max_level, cur->comp_level());
  2665       cur = cur->osr_link();
  2667     m->set_highest_osr_comp_level(max_level);
  2669   // Remember to unlock again
  2670   OsrList_lock->unlock();
  2673 nmethod* InstanceKlass::lookup_osr_nmethod(Method* const m, int bci, int comp_level, bool match_level) const {
  2674   // This is a short non-blocking critical region, so the no safepoint check is ok.
  2675   OsrList_lock->lock_without_safepoint_check();
  2676   nmethod* osr = osr_nmethods_head();
  2677   nmethod* best = NULL;
  2678   while (osr != NULL) {
  2679     assert(osr->is_osr_method(), "wrong kind of nmethod found in chain");
  2680     // There can be a time when a c1 osr method exists but we are waiting
  2681     // for a c2 version. When c2 completes its osr nmethod we will trash
  2682     // the c1 version and only be able to find the c2 version. However
  2683     // while we overflow in the c1 code at back branches we don't want to
  2684     // try and switch to the same code as we are already running
  2686     if (osr->method() == m &&
  2687         (bci == InvocationEntryBci || osr->osr_entry_bci() == bci)) {
  2688       if (match_level) {
  2689         if (osr->comp_level() == comp_level) {
  2690           // Found a match - return it.
  2691           OsrList_lock->unlock();
  2692           return osr;
  2694       } else {
  2695         if (best == NULL || (osr->comp_level() > best->comp_level())) {
  2696           if (osr->comp_level() == CompLevel_highest_tier) {
  2697             // Found the best possible - return it.
  2698             OsrList_lock->unlock();
  2699             return osr;
  2701           best = osr;
  2705     osr = osr->osr_link();
  2707   OsrList_lock->unlock();
  2708   if (best != NULL && best->comp_level() >= comp_level && match_level == false) {
  2709     return best;
  2711   return NULL;
  2714 // -----------------------------------------------------------------------------------------------------
  2715 // Printing
  2717 #ifndef PRODUCT
  2719 #define BULLET  " - "
  2721 static const char* state_names[] = {
  2722   "allocated", "loaded", "linked", "being_initialized", "fully_initialized", "initialization_error"
  2723 };
  2725 void InstanceKlass::print_on(outputStream* st) const {
  2726   assert(is_klass(), "must be klass");
  2727   Klass::print_on(st);
  2729   st->print(BULLET"instance size:     %d", size_helper());                        st->cr();
  2730   st->print(BULLET"klass size:        %d", size());                               st->cr();
  2731   st->print(BULLET"access:            "); access_flags().print_on(st);            st->cr();
  2732   st->print(BULLET"state:             "); st->print_cr(state_names[_init_state]);
  2733   st->print(BULLET"name:              "); name()->print_value_on(st);             st->cr();
  2734   st->print(BULLET"super:             "); super()->print_value_on_maybe_null(st); st->cr();
  2735   st->print(BULLET"sub:               ");
  2736   Klass* sub = subklass();
  2737   int n;
  2738   for (n = 0; sub != NULL; n++, sub = sub->next_sibling()) {
  2739     if (n < MaxSubklassPrintSize) {
  2740       sub->print_value_on(st);
  2741       st->print("   ");
  2744   if (n >= MaxSubklassPrintSize) st->print("(%d more klasses...)", n - MaxSubklassPrintSize);
  2745   st->cr();
  2747   if (is_interface()) {
  2748     st->print_cr(BULLET"nof implementors:  %d", nof_implementors());
  2749     if (nof_implementors() == 1) {
  2750       st->print_cr(BULLET"implementor:    ");
  2751       st->print("   ");
  2752       implementor()->print_value_on(st);
  2753       st->cr();
  2757   st->print(BULLET"arrays:            "); array_klasses()->print_value_on_maybe_null(st); st->cr();
  2758   st->print(BULLET"methods:           "); methods()->print_value_on(st);                  st->cr();
  2759   if (Verbose) {
  2760     Array<Method*>* method_array = methods();
  2761     for(int i = 0; i < method_array->length(); i++) {
  2762       st->print("%d : ", i); method_array->at(i)->print_value(); st->cr();
  2765   st->print(BULLET"method ordering:   "); method_ordering()->print_value_on(st);       st->cr();
  2766   st->print(BULLET"local interfaces:  "); local_interfaces()->print_value_on(st);      st->cr();
  2767   st->print(BULLET"trans. interfaces: "); transitive_interfaces()->print_value_on(st); st->cr();
  2768   st->print(BULLET"constants:         "); constants()->print_value_on(st);         st->cr();
  2769   if (class_loader_data() != NULL) {
  2770     st->print(BULLET"class loader data:  ");
  2771     class_loader_data()->print_value_on(st);
  2772     st->cr();
  2774   st->print(BULLET"protection domain: "); ((InstanceKlass*)this)->protection_domain()->print_value_on(st); st->cr();
  2775   st->print(BULLET"host class:        "); host_klass()->print_value_on_maybe_null(st); st->cr();
  2776   st->print(BULLET"signers:           "); signers()->print_value_on(st);               st->cr();
  2777   st->print(BULLET"init_lock:         "); ((oop)init_lock())->print_value_on(st);             st->cr();
  2778   if (source_file_name() != NULL) {
  2779     st->print(BULLET"source file:       ");
  2780     source_file_name()->print_value_on(st);
  2781     st->cr();
  2783   if (source_debug_extension() != NULL) {
  2784     st->print(BULLET"source debug extension:       ");
  2785     st->print("%s", source_debug_extension());
  2786     st->cr();
  2788   st->print(BULLET"annotations:       "); annotations()->print_value_on(st); st->cr();
  2790     ResourceMark rm;
  2791     // PreviousVersionInfo objects returned via PreviousVersionWalker
  2792     // contain a GrowableArray of handles. We have to clean up the
  2793     // GrowableArray _after_ the PreviousVersionWalker destructor
  2794     // has destroyed the handles.
  2796       bool have_pv = false;
  2797       PreviousVersionWalker pvw((InstanceKlass*)this);
  2798       for (PreviousVersionInfo * pv_info = pvw.next_previous_version();
  2799            pv_info != NULL; pv_info = pvw.next_previous_version()) {
  2800         if (!have_pv)
  2801           st->print(BULLET"previous version:  ");
  2802         have_pv = true;
  2803         pv_info->prev_constant_pool_handle()()->print_value_on(st);
  2805       if (have_pv)  st->cr();
  2806     } // pvw is cleaned up
  2807   } // rm is cleaned up
  2809   if (generic_signature() != NULL) {
  2810     st->print(BULLET"generic signature: ");
  2811     generic_signature()->print_value_on(st);
  2812     st->cr();
  2814   st->print(BULLET"inner classes:     "); inner_classes()->print_value_on(st);     st->cr();
  2815   st->print(BULLET"java mirror:       "); java_mirror()->print_value_on(st);       st->cr();
  2816   st->print(BULLET"vtable length      %d  (start addr: " INTPTR_FORMAT ")", vtable_length(), start_of_vtable());  st->cr();
  2817   st->print(BULLET"itable length      %d (start addr: " INTPTR_FORMAT ")", itable_length(), start_of_itable()); st->cr();
  2818   st->print_cr(BULLET"---- static fields (%d words):", static_field_size());
  2819   FieldPrinter print_static_field(st);
  2820   ((InstanceKlass*)this)->do_local_static_fields(&print_static_field);
  2821   st->print_cr(BULLET"---- non-static fields (%d words):", nonstatic_field_size());
  2822   FieldPrinter print_nonstatic_field(st);
  2823   ((InstanceKlass*)this)->do_nonstatic_fields(&print_nonstatic_field);
  2825   st->print(BULLET"non-static oop maps: ");
  2826   OopMapBlock* map     = start_of_nonstatic_oop_maps();
  2827   OopMapBlock* end_map = map + nonstatic_oop_map_count();
  2828   while (map < end_map) {
  2829     st->print("%d-%d ", map->offset(), map->offset() + heapOopSize*(map->count() - 1));
  2830     map++;
  2832   st->cr();
  2835 #endif //PRODUCT
  2837 void InstanceKlass::print_value_on(outputStream* st) const {
  2838   assert(is_klass(), "must be klass");
  2839   name()->print_value_on(st);
  2842 #ifndef PRODUCT
  2844 void FieldPrinter::do_field(fieldDescriptor* fd) {
  2845   _st->print(BULLET);
  2846    if (_obj == NULL) {
  2847      fd->print_on(_st);
  2848      _st->cr();
  2849    } else {
  2850      fd->print_on_for(_st, _obj);
  2851      _st->cr();
  2856 void InstanceKlass::oop_print_on(oop obj, outputStream* st) {
  2857   Klass::oop_print_on(obj, st);
  2859   if (this == SystemDictionary::String_klass()) {
  2860     typeArrayOop value  = java_lang_String::value(obj);
  2861     juint        offset = java_lang_String::offset(obj);
  2862     juint        length = java_lang_String::length(obj);
  2863     if (value != NULL &&
  2864         value->is_typeArray() &&
  2865         offset          <= (juint) value->length() &&
  2866         offset + length <= (juint) value->length()) {
  2867       st->print(BULLET"string: ");
  2868       Handle h_obj(obj);
  2869       java_lang_String::print(h_obj, st);
  2870       st->cr();
  2871       if (!WizardMode)  return;  // that is enough
  2875   st->print_cr(BULLET"---- fields (total size %d words):", oop_size(obj));
  2876   FieldPrinter print_field(st, obj);
  2877   do_nonstatic_fields(&print_field);
  2879   if (this == SystemDictionary::Class_klass()) {
  2880     st->print(BULLET"signature: ");
  2881     java_lang_Class::print_signature(obj, st);
  2882     st->cr();
  2883     Klass* mirrored_klass = java_lang_Class::as_Klass(obj);
  2884     st->print(BULLET"fake entry for mirror: ");
  2885     mirrored_klass->print_value_on_maybe_null(st);
  2886     st->cr();
  2887     st->print(BULLET"fake entry resolved_constructor: ");
  2888     Method* ctor = java_lang_Class::resolved_constructor(obj);
  2889     ctor->print_value_on_maybe_null(st);
  2890     Klass* array_klass = java_lang_Class::array_klass(obj);
  2891     st->cr();
  2892     st->print(BULLET"fake entry for array: ");
  2893     array_klass->print_value_on_maybe_null(st);
  2894     st->cr();
  2895     st->print_cr(BULLET"fake entry for oop_size: %d", java_lang_Class::oop_size(obj));
  2896     st->print_cr(BULLET"fake entry for static_oop_field_count: %d", java_lang_Class::static_oop_field_count(obj));
  2897     Klass* real_klass = java_lang_Class::as_Klass(obj);
  2898     if (real_klass != NULL && real_klass->oop_is_instance()) {
  2899       InstanceKlass::cast(real_klass)->do_local_static_fields(&print_field);
  2901   } else if (this == SystemDictionary::MethodType_klass()) {
  2902     st->print(BULLET"signature: ");
  2903     java_lang_invoke_MethodType::print_signature(obj, st);
  2904     st->cr();
  2908 #endif //PRODUCT
  2910 void InstanceKlass::oop_print_value_on(oop obj, outputStream* st) {
  2911   st->print("a ");
  2912   name()->print_value_on(st);
  2913   obj->print_address_on(st);
  2914   if (this == SystemDictionary::String_klass()
  2915       && java_lang_String::value(obj) != NULL) {
  2916     ResourceMark rm;
  2917     int len = java_lang_String::length(obj);
  2918     int plen = (len < 24 ? len : 12);
  2919     char* str = java_lang_String::as_utf8_string(obj, 0, plen);
  2920     st->print(" = \"%s\"", str);
  2921     if (len > plen)
  2922       st->print("...[%d]", len);
  2923   } else if (this == SystemDictionary::Class_klass()) {
  2924     Klass* k = java_lang_Class::as_Klass(obj);
  2925     st->print(" = ");
  2926     if (k != NULL) {
  2927       k->print_value_on(st);
  2928     } else {
  2929       const char* tname = type2name(java_lang_Class::primitive_type(obj));
  2930       st->print("%s", tname ? tname : "type?");
  2932   } else if (this == SystemDictionary::MethodType_klass()) {
  2933     st->print(" = ");
  2934     java_lang_invoke_MethodType::print_signature(obj, st);
  2935   } else if (java_lang_boxing_object::is_instance(obj)) {
  2936     st->print(" = ");
  2937     java_lang_boxing_object::print(obj, st);
  2938   } else if (this == SystemDictionary::LambdaForm_klass()) {
  2939     oop vmentry = java_lang_invoke_LambdaForm::vmentry(obj);
  2940     if (vmentry != NULL) {
  2941       st->print(" => ");
  2942       vmentry->print_value_on(st);
  2944   } else if (this == SystemDictionary::MemberName_klass()) {
  2945     Metadata* vmtarget = java_lang_invoke_MemberName::vmtarget(obj);
  2946     if (vmtarget != NULL) {
  2947       st->print(" = ");
  2948       vmtarget->print_value_on(st);
  2949     } else {
  2950       java_lang_invoke_MemberName::clazz(obj)->print_value_on(st);
  2951       st->print(".");
  2952       java_lang_invoke_MemberName::name(obj)->print_value_on(st);
  2957 const char* InstanceKlass::internal_name() const {
  2958   return external_name();
  2961 // Verification
  2963 class VerifyFieldClosure: public OopClosure {
  2964  protected:
  2965   template <class T> void do_oop_work(T* p) {
  2966     oop obj = oopDesc::load_decode_heap_oop(p);
  2967     if (!obj->is_oop_or_null()) {
  2968       tty->print_cr("Failed: " PTR_FORMAT " -> " PTR_FORMAT, p, (address)obj);
  2969       Universe::print();
  2970       guarantee(false, "boom");
  2973  public:
  2974   virtual void do_oop(oop* p)       { VerifyFieldClosure::do_oop_work(p); }
  2975   virtual void do_oop(narrowOop* p) { VerifyFieldClosure::do_oop_work(p); }
  2976 };
  2978 void InstanceKlass::verify_on(outputStream* st) {
  2979   Klass::verify_on(st);
  2980   Thread *thread = Thread::current();
  2982 #ifndef PRODUCT
  2983   // Avoid redundant verifies
  2984   if (_verify_count == Universe::verify_count()) return;
  2985   _verify_count = Universe::verify_count();
  2986 #endif
  2987   // Verify that klass is present in SystemDictionary
  2988   if (is_loaded() && !is_anonymous()) {
  2989     Symbol* h_name = name();
  2990     SystemDictionary::verify_obj_klass_present(h_name, class_loader_data());
  2993   // Verify static fields
  2994   VerifyFieldClosure blk;
  2996   // Verify vtables
  2997   if (is_linked()) {
  2998     ResourceMark rm(thread);
  2999     // $$$ This used to be done only for m/s collections.  Doing it
  3000     // always seemed a valid generalization.  (DLD -- 6/00)
  3001     vtable()->verify(st);
  3004   // Verify first subklass
  3005   if (subklass_oop() != NULL) {
  3006     guarantee(subklass_oop()->is_metadata(), "should be in metaspace");
  3007     guarantee(subklass_oop()->is_klass(), "should be klass");
  3010   // Verify siblings
  3011   Klass* super = this->super();
  3012   Klass* sib = next_sibling();
  3013   if (sib != NULL) {
  3014     if (sib == this) {
  3015       fatal(err_msg("subclass points to itself " PTR_FORMAT, sib));
  3018     guarantee(sib->is_metadata(), "should be in metaspace");
  3019     guarantee(sib->is_klass(), "should be klass");
  3020     guarantee(sib->super() == super, "siblings should have same superklass");
  3023   // Verify implementor fields
  3024   Klass* im = implementor();
  3025   if (im != NULL) {
  3026     guarantee(is_interface(), "only interfaces should have implementor set");
  3027     guarantee(im->is_klass(), "should be klass");
  3028     guarantee(!im->is_interface() || im == this,
  3029       "implementors cannot be interfaces");
  3032   // Verify local interfaces
  3033   if (local_interfaces()) {
  3034     Array<Klass*>* local_interfaces = this->local_interfaces();
  3035     for (int j = 0; j < local_interfaces->length(); j++) {
  3036       Klass* e = local_interfaces->at(j);
  3037       guarantee(e->is_klass() && e->is_interface(), "invalid local interface");
  3041   // Verify transitive interfaces
  3042   if (transitive_interfaces() != NULL) {
  3043     Array<Klass*>* transitive_interfaces = this->transitive_interfaces();
  3044     for (int j = 0; j < transitive_interfaces->length(); j++) {
  3045       Klass* e = transitive_interfaces->at(j);
  3046       guarantee(e->is_klass() && e->is_interface(), "invalid transitive interface");
  3050   // Verify methods
  3051   if (methods() != NULL) {
  3052     Array<Method*>* methods = this->methods();
  3053     for (int j = 0; j < methods->length(); j++) {
  3054       guarantee(methods->at(j)->is_metadata(), "should be in metaspace");
  3055       guarantee(methods->at(j)->is_method(), "non-method in methods array");
  3057     for (int j = 0; j < methods->length() - 1; j++) {
  3058       Method* m1 = methods->at(j);
  3059       Method* m2 = methods->at(j + 1);
  3060       guarantee(m1->name()->fast_compare(m2->name()) <= 0, "methods not sorted correctly");
  3064   // Verify method ordering
  3065   if (method_ordering() != NULL) {
  3066     Array<int>* method_ordering = this->method_ordering();
  3067     int length = method_ordering->length();
  3068     if (JvmtiExport::can_maintain_original_method_order() ||
  3069         (UseSharedSpaces && length != 0)) {
  3070       guarantee(length == methods()->length(), "invalid method ordering length");
  3071       jlong sum = 0;
  3072       for (int j = 0; j < length; j++) {
  3073         int original_index = method_ordering->at(j);
  3074         guarantee(original_index >= 0, "invalid method ordering index");
  3075         guarantee(original_index < length, "invalid method ordering index");
  3076         sum += original_index;
  3078       // Verify sum of indices 0,1,...,length-1
  3079       guarantee(sum == ((jlong)length*(length-1))/2, "invalid method ordering sum");
  3080     } else {
  3081       guarantee(length == 0, "invalid method ordering length");
  3085   // Verify JNI static field identifiers
  3086   if (jni_ids() != NULL) {
  3087     jni_ids()->verify(this);
  3090   // Verify other fields
  3091   if (array_klasses() != NULL) {
  3092     guarantee(array_klasses()->is_metadata(), "should be in metaspace");
  3093     guarantee(array_klasses()->is_klass(), "should be klass");
  3095   if (constants() != NULL) {
  3096     guarantee(constants()->is_metadata(), "should be in metaspace");
  3097     guarantee(constants()->is_constantPool(), "should be constant pool");
  3099   if (protection_domain() != NULL) {
  3100     guarantee(protection_domain()->is_oop(), "should be oop");
  3102   if (host_klass() != NULL) {
  3103     guarantee(host_klass()->is_metadata(), "should be in metaspace");
  3104     guarantee(host_klass()->is_klass(), "should be klass");
  3106   if (signers() != NULL) {
  3107     guarantee(signers()->is_objArray(), "should be obj array");
  3111 void InstanceKlass::oop_verify_on(oop obj, outputStream* st) {
  3112   Klass::oop_verify_on(obj, st);
  3113   VerifyFieldClosure blk;
  3114   obj->oop_iterate_no_header(&blk);
  3118 // JNIid class for jfieldIDs only
  3119 // Note to reviewers:
  3120 // These JNI functions are just moved over to column 1 and not changed
  3121 // in the compressed oops workspace.
  3122 JNIid::JNIid(Klass* holder, int offset, JNIid* next) {
  3123   _holder = holder;
  3124   _offset = offset;
  3125   _next = next;
  3126   debug_only(_is_static_field_id = false;)
  3130 JNIid* JNIid::find(int offset) {
  3131   JNIid* current = this;
  3132   while (current != NULL) {
  3133     if (current->offset() == offset) return current;
  3134     current = current->next();
  3136   return NULL;
  3139 void JNIid::deallocate(JNIid* current) {
  3140   while (current != NULL) {
  3141     JNIid* next = current->next();
  3142     delete current;
  3143     current = next;
  3148 void JNIid::verify(Klass* holder) {
  3149   int first_field_offset  = InstanceMirrorKlass::offset_of_static_fields();
  3150   int end_field_offset;
  3151   end_field_offset = first_field_offset + (InstanceKlass::cast(holder)->static_field_size() * wordSize);
  3153   JNIid* current = this;
  3154   while (current != NULL) {
  3155     guarantee(current->holder() == holder, "Invalid klass in JNIid");
  3156 #ifdef ASSERT
  3157     int o = current->offset();
  3158     if (current->is_static_field_id()) {
  3159       guarantee(o >= first_field_offset  && o < end_field_offset,  "Invalid static field offset in JNIid");
  3161 #endif
  3162     current = current->next();
  3167 #ifdef ASSERT
  3168 void InstanceKlass::set_init_state(ClassState state) {
  3169   bool good_state = is_shared() ? (_init_state <= state)
  3170                                                : (_init_state < state);
  3171   assert(good_state || state == allocated, "illegal state transition");
  3172   _init_state = (u1)state;
  3174 #endif
  3177 // RedefineClasses() support for previous versions:
  3179 // Purge previous versions
  3180 static void purge_previous_versions_internal(InstanceKlass* ik, int emcp_method_count) {
  3181   if (ik->previous_versions() != NULL) {
  3182     // This klass has previous versions so see what we can cleanup
  3183     // while it is safe to do so.
  3185     int deleted_count = 0;    // leave debugging breadcrumbs
  3186     int live_count = 0;
  3187     ClassLoaderData* loader_data = ik->class_loader_data() == NULL ?
  3188                        ClassLoaderData::the_null_class_loader_data() :
  3189                        ik->class_loader_data();
  3191     // RC_TRACE macro has an embedded ResourceMark
  3192     RC_TRACE(0x00000200, ("purge: %s: previous version length=%d",
  3193       ik->external_name(), ik->previous_versions()->length()));
  3195     for (int i = ik->previous_versions()->length() - 1; i >= 0; i--) {
  3196       // check the previous versions array
  3197       PreviousVersionNode * pv_node = ik->previous_versions()->at(i);
  3198       ConstantPool* cp_ref = pv_node->prev_constant_pool();
  3199       assert(cp_ref != NULL, "cp ref was unexpectedly cleared");
  3201       ConstantPool* pvcp = cp_ref;
  3202       if (!pvcp->on_stack()) {
  3203         // If the constant pool isn't on stack, none of the methods
  3204         // are executing.  Delete all the methods, the constant pool and
  3205         // and this previous version node.
  3206         GrowableArray<Method*>* method_refs = pv_node->prev_EMCP_methods();
  3207         if (method_refs != NULL) {
  3208           for (int j = method_refs->length() - 1; j >= 0; j--) {
  3209             Method* method = method_refs->at(j);
  3210             assert(method != NULL, "method ref was unexpectedly cleared");
  3211             method_refs->remove_at(j);
  3212             // method will be freed with associated class.
  3215         // Remove the constant pool
  3216         delete pv_node;
  3217         // Since we are traversing the array backwards, we don't have to
  3218         // do anything special with the index.
  3219         ik->previous_versions()->remove_at(i);
  3220         deleted_count++;
  3221         continue;
  3222       } else {
  3223         RC_TRACE(0x00000200, ("purge: previous version @%d is alive", i));
  3224         assert(pvcp->pool_holder() != NULL, "Constant pool with no holder");
  3225         guarantee (!loader_data->is_unloading(), "unloaded classes can't be on the stack");
  3226         live_count++;
  3229       // At least one method is live in this previous version, clean out
  3230       // the others or mark them as obsolete.
  3231       GrowableArray<Method*>* method_refs = pv_node->prev_EMCP_methods();
  3232       if (method_refs != NULL) {
  3233         RC_TRACE(0x00000200, ("purge: previous methods length=%d",
  3234           method_refs->length()));
  3235         for (int j = method_refs->length() - 1; j >= 0; j--) {
  3236           Method* method = method_refs->at(j);
  3237           assert(method != NULL, "method ref was unexpectedly cleared");
  3239           // Remove the emcp method if it's not executing
  3240           // If it's been made obsolete by a redefinition of a non-emcp
  3241           // method, mark it as obsolete but leave it to clean up later.
  3242           if (!method->on_stack()) {
  3243             method_refs->remove_at(j);
  3244           } else if (emcp_method_count == 0) {
  3245             method->set_is_obsolete();
  3246           } else {
  3247             // RC_TRACE macro has an embedded ResourceMark
  3248             RC_TRACE(0x00000200,
  3249               ("purge: %s(%s): prev method @%d in version @%d is alive",
  3250               method->name()->as_C_string(),
  3251               method->signature()->as_C_string(), j, i));
  3256     assert(ik->previous_versions()->length() == live_count, "sanity check");
  3257     RC_TRACE(0x00000200,
  3258       ("purge: previous version stats: live=%d, deleted=%d", live_count,
  3259       deleted_count));
  3263 // External interface for use during class unloading.
  3264 void InstanceKlass::purge_previous_versions(InstanceKlass* ik) {
  3265   // Call with >0 emcp methods since they are not currently being redefined.
  3266   purge_previous_versions_internal(ik, 1);
  3270 // Potentially add an information node that contains pointers to the
  3271 // interesting parts of the previous version of the_class.
  3272 // This is also where we clean out any unused references.
  3273 // Note that while we delete nodes from the _previous_versions
  3274 // array, we never delete the array itself until the klass is
  3275 // unloaded. The has_been_redefined() query depends on that fact.
  3276 //
  3277 void InstanceKlass::add_previous_version(instanceKlassHandle ikh,
  3278        BitMap* emcp_methods, int emcp_method_count) {
  3279   assert(Thread::current()->is_VM_thread(),
  3280          "only VMThread can add previous versions");
  3282   if (_previous_versions == NULL) {
  3283     // This is the first previous version so make some space.
  3284     // Start with 2 elements under the assumption that the class
  3285     // won't be redefined much.
  3286     _previous_versions =  new (ResourceObj::C_HEAP, mtClass)
  3287                             GrowableArray<PreviousVersionNode *>(2, true);
  3290   ConstantPool* cp_ref = ikh->constants();
  3292   // RC_TRACE macro has an embedded ResourceMark
  3293   RC_TRACE(0x00000400, ("adding previous version ref for %s @%d, EMCP_cnt=%d "
  3294                         "on_stack=%d",
  3295     ikh->external_name(), _previous_versions->length(), emcp_method_count,
  3296     cp_ref->on_stack()));
  3298   // If the constant pool for this previous version of the class
  3299   // is not marked as being on the stack, then none of the methods
  3300   // in this previous version of the class are on the stack so
  3301   // we don't need to create a new PreviousVersionNode. However,
  3302   // we still need to examine older previous versions below.
  3303   Array<Method*>* old_methods = ikh->methods();
  3305   if (cp_ref->on_stack()) {
  3306   PreviousVersionNode * pv_node = NULL;
  3307   if (emcp_method_count == 0) {
  3308       // non-shared ConstantPool gets a reference
  3309       pv_node = new PreviousVersionNode(cp_ref, !cp_ref->is_shared(), NULL);
  3310     RC_TRACE(0x00000400,
  3311         ("add: all methods are obsolete; flushing any EMCP refs"));
  3312   } else {
  3313     int local_count = 0;
  3314       GrowableArray<Method*>* method_refs = new (ResourceObj::C_HEAP, mtClass)
  3315         GrowableArray<Method*>(emcp_method_count, true);
  3316     for (int i = 0; i < old_methods->length(); i++) {
  3317       if (emcp_methods->at(i)) {
  3318           // this old method is EMCP. Save it only if it's on the stack
  3319           Method* old_method = old_methods->at(i);
  3320           if (old_method->on_stack()) {
  3321             method_refs->append(old_method);
  3323         if (++local_count >= emcp_method_count) {
  3324           // no more EMCP methods so bail out now
  3325           break;
  3329       // non-shared ConstantPool gets a reference
  3330       pv_node = new PreviousVersionNode(cp_ref, !cp_ref->is_shared(), method_refs);
  3332     // append new previous version.
  3333   _previous_versions->append(pv_node);
  3336   // Since the caller is the VMThread and we are at a safepoint, this
  3337   // is a good time to clear out unused references.
  3339   RC_TRACE(0x00000400, ("add: previous version length=%d",
  3340     _previous_versions->length()));
  3342   // Purge previous versions not executing on the stack
  3343   purge_previous_versions_internal(this, emcp_method_count);
  3345   int obsolete_method_count = old_methods->length() - emcp_method_count;
  3347   if (emcp_method_count != 0 && obsolete_method_count != 0 &&
  3348       _previous_versions->length() > 0) {
  3349     // We have a mix of obsolete and EMCP methods so we have to
  3350     // clear out any matching EMCP method entries the hard way.
  3351     int local_count = 0;
  3352     for (int i = 0; i < old_methods->length(); i++) {
  3353       if (!emcp_methods->at(i)) {
  3354         // only obsolete methods are interesting
  3355         Method* old_method = old_methods->at(i);
  3356         Symbol* m_name = old_method->name();
  3357         Symbol* m_signature = old_method->signature();
  3359         // we might not have added the last entry
  3360         for (int j = _previous_versions->length() - 1; j >= 0; j--) {
  3361           // check the previous versions array for non executing obsolete methods
  3362           PreviousVersionNode * pv_node = _previous_versions->at(j);
  3364           GrowableArray<Method*>* method_refs = pv_node->prev_EMCP_methods();
  3365           if (method_refs == NULL) {
  3366             // We have run into a PreviousVersion generation where
  3367             // all methods were made obsolete during that generation's
  3368             // RedefineClasses() operation. At the time of that
  3369             // operation, all EMCP methods were flushed so we don't
  3370             // have to go back any further.
  3371             //
  3372             // A NULL method_refs is different than an empty method_refs.
  3373             // We cannot infer any optimizations about older generations
  3374             // from an empty method_refs for the current generation.
  3375             break;
  3378           for (int k = method_refs->length() - 1; k >= 0; k--) {
  3379             Method* method = method_refs->at(k);
  3381             if (!method->is_obsolete() &&
  3382                 method->name() == m_name &&
  3383                 method->signature() == m_signature) {
  3384               // The current RedefineClasses() call has made all EMCP
  3385               // versions of this method obsolete so mark it as obsolete
  3386               // and remove the reference.
  3387               RC_TRACE(0x00000400,
  3388                 ("add: %s(%s): flush obsolete method @%d in version @%d",
  3389                 m_name->as_C_string(), m_signature->as_C_string(), k, j));
  3391               method->set_is_obsolete();
  3392               // Leave obsolete methods on the previous version list to
  3393               // clean up later.
  3394               break;
  3398           // The previous loop may not find a matching EMCP method, but
  3399           // that doesn't mean that we can optimize and not go any
  3400           // further back in the PreviousVersion generations. The EMCP
  3401           // method for this generation could have already been deleted,
  3402           // but there still may be an older EMCP method that has not
  3403           // been deleted.
  3406         if (++local_count >= obsolete_method_count) {
  3407           // no more obsolete methods so bail out now
  3408           break;
  3413 } // end add_previous_version()
  3416 // Determine if InstanceKlass has a previous version.
  3417 bool InstanceKlass::has_previous_version() const {
  3418   return (_previous_versions != NULL && _previous_versions->length() > 0);
  3419 } // end has_previous_version()
  3422 Method* InstanceKlass::method_with_idnum(int idnum) {
  3423   Method* m = NULL;
  3424   if (idnum < methods()->length()) {
  3425     m = methods()->at(idnum);
  3427   if (m == NULL || m->method_idnum() != idnum) {
  3428     for (int index = 0; index < methods()->length(); ++index) {
  3429       m = methods()->at(index);
  3430       if (m->method_idnum() == idnum) {
  3431         return m;
  3435   return m;
  3439 // Construct a PreviousVersionNode entry for the array hung off
  3440 // the InstanceKlass.
  3441 PreviousVersionNode::PreviousVersionNode(ConstantPool* prev_constant_pool,
  3442   bool prev_cp_is_weak, GrowableArray<Method*>* prev_EMCP_methods) {
  3444   _prev_constant_pool = prev_constant_pool;
  3445   _prev_cp_is_weak = prev_cp_is_weak;
  3446   _prev_EMCP_methods = prev_EMCP_methods;
  3450 // Destroy a PreviousVersionNode
  3451 PreviousVersionNode::~PreviousVersionNode() {
  3452   if (_prev_constant_pool != NULL) {
  3453     _prev_constant_pool = NULL;
  3456   if (_prev_EMCP_methods != NULL) {
  3457     delete _prev_EMCP_methods;
  3462 // Construct a PreviousVersionInfo entry
  3463 PreviousVersionInfo::PreviousVersionInfo(PreviousVersionNode *pv_node) {
  3464   _prev_constant_pool_handle = constantPoolHandle();  // NULL handle
  3465   _prev_EMCP_method_handles = NULL;
  3467   ConstantPool* cp = pv_node->prev_constant_pool();
  3468   assert(cp != NULL, "constant pool ref was unexpectedly cleared");
  3469   if (cp == NULL) {
  3470     return;  // robustness
  3473   // make the ConstantPool* safe to return
  3474   _prev_constant_pool_handle = constantPoolHandle(cp);
  3476   GrowableArray<Method*>* method_refs = pv_node->prev_EMCP_methods();
  3477   if (method_refs == NULL) {
  3478     // the InstanceKlass did not have any EMCP methods
  3479     return;
  3482   _prev_EMCP_method_handles = new GrowableArray<methodHandle>(10);
  3484   int n_methods = method_refs->length();
  3485   for (int i = 0; i < n_methods; i++) {
  3486     Method* method = method_refs->at(i);
  3487     assert (method != NULL, "method has been cleared");
  3488     if (method == NULL) {
  3489       continue;  // robustness
  3491     // make the Method* safe to return
  3492     _prev_EMCP_method_handles->append(methodHandle(method));
  3497 // Destroy a PreviousVersionInfo
  3498 PreviousVersionInfo::~PreviousVersionInfo() {
  3499   // Since _prev_EMCP_method_handles is not C-heap allocated, we
  3500   // don't have to delete it.
  3504 // Construct a helper for walking the previous versions array
  3505 PreviousVersionWalker::PreviousVersionWalker(InstanceKlass *ik) {
  3506   _previous_versions = ik->previous_versions();
  3507   _current_index = 0;
  3508   // _hm needs no initialization
  3509   _current_p = NULL;
  3513 // Destroy a PreviousVersionWalker
  3514 PreviousVersionWalker::~PreviousVersionWalker() {
  3515   // Delete the current info just in case the caller didn't walk to
  3516   // the end of the previous versions list. No harm if _current_p is
  3517   // already NULL.
  3518   delete _current_p;
  3520   // When _hm is destroyed, all the Handles returned in
  3521   // PreviousVersionInfo objects will be destroyed.
  3522   // Also, after this destructor is finished it will be
  3523   // safe to delete the GrowableArray allocated in the
  3524   // PreviousVersionInfo objects.
  3528 // Return the interesting information for the next previous version
  3529 // of the klass. Returns NULL if there are no more previous versions.
  3530 PreviousVersionInfo* PreviousVersionWalker::next_previous_version() {
  3531   if (_previous_versions == NULL) {
  3532     // no previous versions so nothing to return
  3533     return NULL;
  3536   delete _current_p;  // cleanup the previous info for the caller
  3537   _current_p = NULL;  // reset to NULL so we don't delete same object twice
  3539   int length = _previous_versions->length();
  3541   while (_current_index < length) {
  3542     PreviousVersionNode * pv_node = _previous_versions->at(_current_index++);
  3543     PreviousVersionInfo * pv_info = new (ResourceObj::C_HEAP, mtClass)
  3544                                           PreviousVersionInfo(pv_node);
  3546     constantPoolHandle cp_h = pv_info->prev_constant_pool_handle();
  3547     assert (!cp_h.is_null(), "null cp found in previous version");
  3549     // The caller will need to delete pv_info when they are done with it.
  3550     _current_p = pv_info;
  3551     return pv_info;
  3554   // all of the underlying nodes' info has been deleted
  3555   return NULL;
  3556 } // end next_previous_version()

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