src/share/vm/oops/instanceKlass.cpp

Fri, 20 Sep 2013 09:30:02 -0400

author
coleenp
date
Fri, 20 Sep 2013 09:30:02 -0400
changeset 5749
4f9a42c33738
parent 5535
e22ee8e7ae62
child 5755
0f37d1badced
permissions
-rw-r--r--

8022887: Assertion hit while using class and redefining it with RedefineClasses simultaneously
Summary: Need to refetch each method from InstanceKlass after all safepoints. Removed leaky PreviousVersionInfo code.
Reviewed-by: dcubed, sspitsyn

     1 /*
     2  * Copyright (c) 1997, 2013, 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/heapInspection.hpp"
    38 #include "memory/metadataFactory.hpp"
    39 #include "memory/oopFactory.hpp"
    40 #include "oops/fieldStreams.hpp"
    41 #include "oops/instanceClassLoaderKlass.hpp"
    42 #include "oops/instanceKlass.hpp"
    43 #include "oops/instanceMirrorKlass.hpp"
    44 #include "oops/instanceOop.hpp"
    45 #include "oops/klass.inline.hpp"
    46 #include "oops/method.hpp"
    47 #include "oops/oop.inline.hpp"
    48 #include "oops/symbol.hpp"
    49 #include "prims/jvmtiExport.hpp"
    50 #include "prims/jvmtiRedefineClassesTrace.hpp"
    51 #include "prims/jvmtiRedefineClasses.hpp"
    52 #include "prims/methodComparator.hpp"
    53 #include "runtime/fieldDescriptor.hpp"
    54 #include "runtime/handles.inline.hpp"
    55 #include "runtime/javaCalls.hpp"
    56 #include "runtime/mutexLocker.hpp"
    57 #include "runtime/thread.inline.hpp"
    58 #include "services/classLoadingService.hpp"
    59 #include "services/threadService.hpp"
    60 #include "utilities/dtrace.hpp"
    61 #include "utilities/macros.hpp"
    62 #if INCLUDE_ALL_GCS
    63 #include "gc_implementation/concurrentMarkSweep/cmsOopClosures.inline.hpp"
    64 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
    65 #include "gc_implementation/g1/g1OopClosures.inline.hpp"
    66 #include "gc_implementation/g1/g1RemSet.inline.hpp"
    67 #include "gc_implementation/g1/heapRegionSeq.inline.hpp"
    68 #include "gc_implementation/parNew/parOopClosures.inline.hpp"
    69 #include "gc_implementation/parallelScavenge/parallelScavengeHeap.inline.hpp"
    70 #include "gc_implementation/parallelScavenge/psPromotionManager.inline.hpp"
    71 #include "gc_implementation/parallelScavenge/psScavenge.inline.hpp"
    72 #include "oops/oop.pcgc.inline.hpp"
    73 #endif // INCLUDE_ALL_GCS
    74 #ifdef COMPILER1
    75 #include "c1/c1_Compiler.hpp"
    76 #endif
    78 #ifdef DTRACE_ENABLED
    80 #ifndef USDT2
    82 HS_DTRACE_PROBE_DECL4(hotspot, class__initialization__required,
    83   char*, intptr_t, oop, intptr_t);
    84 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__recursive,
    85   char*, intptr_t, oop, intptr_t, int);
    86 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__concurrent,
    87   char*, intptr_t, oop, intptr_t, int);
    88 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__erroneous,
    89   char*, intptr_t, oop, intptr_t, int);
    90 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__super__failed,
    91   char*, intptr_t, oop, intptr_t, int);
    92 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__clinit,
    93   char*, intptr_t, oop, intptr_t, int);
    94 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__error,
    95   char*, intptr_t, oop, intptr_t, int);
    96 HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__end,
    97   char*, intptr_t, oop, intptr_t, int);
    99 #define DTRACE_CLASSINIT_PROBE(type, clss, thread_type)          \
   100   {                                                              \
   101     char* data = NULL;                                           \
   102     int len = 0;                                                 \
   103     Symbol* name = (clss)->name();                               \
   104     if (name != NULL) {                                          \
   105       data = (char*)name->bytes();                               \
   106       len = name->utf8_length();                                 \
   107     }                                                            \
   108     HS_DTRACE_PROBE4(hotspot, class__initialization__##type,     \
   109       data, len, (clss)->class_loader(), thread_type);           \
   110   }
   112 #define DTRACE_CLASSINIT_PROBE_WAIT(type, clss, thread_type, wait) \
   113   {                                                              \
   114     char* data = NULL;                                           \
   115     int len = 0;                                                 \
   116     Symbol* name = (clss)->name();                               \
   117     if (name != NULL) {                                          \
   118       data = (char*)name->bytes();                               \
   119       len = name->utf8_length();                                 \
   120     }                                                            \
   121     HS_DTRACE_PROBE5(hotspot, class__initialization__##type,     \
   122       data, len, (clss)->class_loader(), thread_type, wait);     \
   123   }
   124 #else /* USDT2 */
   126 #define HOTSPOT_CLASS_INITIALIZATION_required HOTSPOT_CLASS_INITIALIZATION_REQUIRED
   127 #define HOTSPOT_CLASS_INITIALIZATION_recursive HOTSPOT_CLASS_INITIALIZATION_RECURSIVE
   128 #define HOTSPOT_CLASS_INITIALIZATION_concurrent HOTSPOT_CLASS_INITIALIZATION_CONCURRENT
   129 #define HOTSPOT_CLASS_INITIALIZATION_erroneous HOTSPOT_CLASS_INITIALIZATION_ERRONEOUS
   130 #define HOTSPOT_CLASS_INITIALIZATION_super__failed HOTSPOT_CLASS_INITIALIZATION_SUPER_FAILED
   131 #define HOTSPOT_CLASS_INITIALIZATION_clinit HOTSPOT_CLASS_INITIALIZATION_CLINIT
   132 #define HOTSPOT_CLASS_INITIALIZATION_error HOTSPOT_CLASS_INITIALIZATION_ERROR
   133 #define HOTSPOT_CLASS_INITIALIZATION_end HOTSPOT_CLASS_INITIALIZATION_END
   134 #define DTRACE_CLASSINIT_PROBE(type, clss, thread_type)          \
   135   {                                                              \
   136     char* data = NULL;                                           \
   137     int len = 0;                                                 \
   138     Symbol* name = (clss)->name();                               \
   139     if (name != NULL) {                                          \
   140       data = (char*)name->bytes();                               \
   141       len = name->utf8_length();                                 \
   142     }                                                            \
   143     HOTSPOT_CLASS_INITIALIZATION_##type(                         \
   144       data, len, (clss)->class_loader(), thread_type);           \
   145   }
   147 #define DTRACE_CLASSINIT_PROBE_WAIT(type, clss, thread_type, wait) \
   148   {                                                              \
   149     char* data = NULL;                                           \
   150     int len = 0;                                                 \
   151     Symbol* name = (clss)->name();                               \
   152     if (name != NULL) {                                          \
   153       data = (char*)name->bytes();                               \
   154       len = name->utf8_length();                                 \
   155     }                                                            \
   156     HOTSPOT_CLASS_INITIALIZATION_##type(                         \
   157       data, len, (clss)->class_loader(), thread_type, wait);     \
   158   }
   159 #endif /* USDT2 */
   161 #else //  ndef DTRACE_ENABLED
   163 #define DTRACE_CLASSINIT_PROBE(type, clss, thread_type)
   164 #define DTRACE_CLASSINIT_PROBE_WAIT(type, clss, thread_type, wait)
   166 #endif //  ndef DTRACE_ENABLED
   168 volatile int InstanceKlass::_total_instanceKlass_count = 0;
   170 InstanceKlass* InstanceKlass::allocate_instance_klass(
   171                                               ClassLoaderData* loader_data,
   172                                               int vtable_len,
   173                                               int itable_len,
   174                                               int static_field_size,
   175                                               int nonstatic_oop_map_size,
   176                                               ReferenceType rt,
   177                                               AccessFlags access_flags,
   178                                               Symbol* name,
   179                                               Klass* super_klass,
   180                                               bool is_anonymous,
   181                                               TRAPS) {
   183   int size = InstanceKlass::size(vtable_len, itable_len, nonstatic_oop_map_size,
   184                                  access_flags.is_interface(), is_anonymous);
   186   // Allocation
   187   InstanceKlass* ik;
   188   if (rt == REF_NONE) {
   189     if (name == vmSymbols::java_lang_Class()) {
   190       ik = new (loader_data, size, THREAD) InstanceMirrorKlass(
   191         vtable_len, itable_len, static_field_size, nonstatic_oop_map_size, rt,
   192         access_flags, is_anonymous);
   193     } else if (name == vmSymbols::java_lang_ClassLoader() ||
   194           (SystemDictionary::ClassLoader_klass_loaded() &&
   195           super_klass != NULL &&
   196           super_klass->is_subtype_of(SystemDictionary::ClassLoader_klass()))) {
   197       ik = new (loader_data, size, THREAD) InstanceClassLoaderKlass(
   198         vtable_len, itable_len, static_field_size, nonstatic_oop_map_size, rt,
   199         access_flags, is_anonymous);
   200     } else {
   201       // normal class
   202       ik = new (loader_data, size, THREAD) InstanceKlass(
   203         vtable_len, itable_len, static_field_size, nonstatic_oop_map_size, rt,
   204         access_flags, is_anonymous);
   205     }
   206   } else {
   207     // reference klass
   208     ik = new (loader_data, size, THREAD) InstanceRefKlass(
   209         vtable_len, itable_len, static_field_size, nonstatic_oop_map_size, rt,
   210         access_flags, is_anonymous);
   211   }
   213   // Check for pending exception before adding to the loader data and incrementing
   214   // class count.  Can get OOM here.
   215   if (HAS_PENDING_EXCEPTION) {
   216     return NULL;
   217   }
   219   // Add all classes to our internal class loader list here,
   220   // including classes in the bootstrap (NULL) class loader.
   221   loader_data->add_class(ik);
   223   Atomic::inc(&_total_instanceKlass_count);
   224   return ik;
   225 }
   228 // copy method ordering from resource area to Metaspace
   229 void InstanceKlass::copy_method_ordering(intArray* m, TRAPS) {
   230   if (m != NULL) {
   231     // allocate a new array and copy contents (memcpy?)
   232     _method_ordering = MetadataFactory::new_array<int>(class_loader_data(), m->length(), CHECK);
   233     for (int i = 0; i < m->length(); i++) {
   234       _method_ordering->at_put(i, m->at(i));
   235     }
   236   } else {
   237     _method_ordering = Universe::the_empty_int_array();
   238   }
   239 }
   242 InstanceKlass::InstanceKlass(int vtable_len,
   243                              int itable_len,
   244                              int static_field_size,
   245                              int nonstatic_oop_map_size,
   246                              ReferenceType rt,
   247                              AccessFlags access_flags,
   248                              bool is_anonymous) {
   249   No_Safepoint_Verifier no_safepoint; // until k becomes parsable
   251   int iksize = InstanceKlass::size(vtable_len, itable_len, nonstatic_oop_map_size,
   252                                    access_flags.is_interface(), is_anonymous);
   254   set_vtable_length(vtable_len);
   255   set_itable_length(itable_len);
   256   set_static_field_size(static_field_size);
   257   set_nonstatic_oop_map_size(nonstatic_oop_map_size);
   258   set_access_flags(access_flags);
   259   _misc_flags = 0;  // initialize to zero
   260   set_is_anonymous(is_anonymous);
   261   assert(size() == iksize, "wrong size for object");
   263   set_array_klasses(NULL);
   264   set_methods(NULL);
   265   set_method_ordering(NULL);
   266   set_local_interfaces(NULL);
   267   set_transitive_interfaces(NULL);
   268   init_implementor();
   269   set_fields(NULL, 0);
   270   set_constants(NULL);
   271   set_class_loader_data(NULL);
   272   set_source_file_name_index(0);
   273   set_source_debug_extension(NULL, 0);
   274   set_array_name(NULL);
   275   set_inner_classes(NULL);
   276   set_static_oop_field_count(0);
   277   set_nonstatic_field_size(0);
   278   set_is_marked_dependent(false);
   279   set_init_state(InstanceKlass::allocated);
   280   set_init_thread(NULL);
   281   set_reference_type(rt);
   282   set_oop_map_cache(NULL);
   283   set_jni_ids(NULL);
   284   set_osr_nmethods_head(NULL);
   285   set_breakpoints(NULL);
   286   init_previous_versions();
   287   set_generic_signature_index(0);
   288   release_set_methods_jmethod_ids(NULL);
   289   release_set_methods_cached_itable_indices(NULL);
   290   set_annotations(NULL);
   291   set_jvmti_cached_class_field_map(NULL);
   292   set_initial_method_idnum(0);
   293   _dependencies = NULL;
   294   set_jvmti_cached_class_field_map(NULL);
   295   set_cached_class_file(NULL);
   296   set_initial_method_idnum(0);
   297   set_minor_version(0);
   298   set_major_version(0);
   299   NOT_PRODUCT(_verify_count = 0;)
   301   // initialize the non-header words to zero
   302   intptr_t* p = (intptr_t*)this;
   303   for (int index = InstanceKlass::header_size(); index < iksize; index++) {
   304     p[index] = NULL_WORD;
   305   }
   307   // Set temporary value until parseClassFile updates it with the real instance
   308   // size.
   309   set_layout_helper(Klass::instance_layout_helper(0, true));
   310 }
   313 void InstanceKlass::deallocate_methods(ClassLoaderData* loader_data,
   314                                        Array<Method*>* methods) {
   315   if (methods != NULL && methods != Universe::the_empty_method_array()) {
   316     for (int i = 0; i < methods->length(); i++) {
   317       Method* method = methods->at(i);
   318       if (method == NULL) continue;  // maybe null if error processing
   319       // Only want to delete methods that are not executing for RedefineClasses.
   320       // The previous version will point to them so they're not totally dangling
   321       assert (!method->on_stack(), "shouldn't be called with methods on stack");
   322       MetadataFactory::free_metadata(loader_data, method);
   323     }
   324     MetadataFactory::free_array<Method*>(loader_data, methods);
   325   }
   326 }
   328 void InstanceKlass::deallocate_interfaces(ClassLoaderData* loader_data,
   329                                           Klass* super_klass,
   330                                           Array<Klass*>* local_interfaces,
   331                                           Array<Klass*>* transitive_interfaces) {
   332   // Only deallocate transitive interfaces if not empty, same as super class
   333   // or same as local interfaces.  See code in parseClassFile.
   334   Array<Klass*>* ti = transitive_interfaces;
   335   if (ti != Universe::the_empty_klass_array() && ti != local_interfaces) {
   336     // check that the interfaces don't come from super class
   337     Array<Klass*>* sti = (super_klass == NULL) ? NULL :
   338                     InstanceKlass::cast(super_klass)->transitive_interfaces();
   339     if (ti != sti) {
   340       MetadataFactory::free_array<Klass*>(loader_data, ti);
   341     }
   342   }
   344   // local interfaces can be empty
   345   if (local_interfaces != Universe::the_empty_klass_array()) {
   346     MetadataFactory::free_array<Klass*>(loader_data, local_interfaces);
   347   }
   348 }
   350 // This function deallocates the metadata and C heap pointers that the
   351 // InstanceKlass points to.
   352 void InstanceKlass::deallocate_contents(ClassLoaderData* loader_data) {
   354   // Orphan the mirror first, CMS thinks it's still live.
   355   if (java_mirror() != NULL) {
   356     java_lang_Class::set_klass(java_mirror(), NULL);
   357   }
   359   // Need to take this class off the class loader data list.
   360   loader_data->remove_class(this);
   362   // The array_klass for this class is created later, after error handling.
   363   // For class redefinition, we keep the original class so this scratch class
   364   // doesn't have an array class.  Either way, assert that there is nothing
   365   // to deallocate.
   366   assert(array_klasses() == NULL, "array classes shouldn't be created for this class yet");
   368   // Release C heap allocated data that this might point to, which includes
   369   // reference counting symbol names.
   370   release_C_heap_structures();
   372   deallocate_methods(loader_data, methods());
   373   set_methods(NULL);
   375   if (method_ordering() != Universe::the_empty_int_array()) {
   376     MetadataFactory::free_array<int>(loader_data, method_ordering());
   377   }
   378   set_method_ordering(NULL);
   380   // This array is in Klass, but remove it with the InstanceKlass since
   381   // this place would be the only caller and it can share memory with transitive
   382   // interfaces.
   383   if (secondary_supers() != Universe::the_empty_klass_array() &&
   384       secondary_supers() != transitive_interfaces()) {
   385     MetadataFactory::free_array<Klass*>(loader_data, secondary_supers());
   386   }
   387   set_secondary_supers(NULL);
   389   deallocate_interfaces(loader_data, super(), local_interfaces(), transitive_interfaces());
   390   set_transitive_interfaces(NULL);
   391   set_local_interfaces(NULL);
   393   MetadataFactory::free_array<jushort>(loader_data, fields());
   394   set_fields(NULL, 0);
   396   // If a method from a redefined class is using this constant pool, don't
   397   // delete it, yet.  The new class's previous version will point to this.
   398   if (constants() != NULL) {
   399     assert (!constants()->on_stack(), "shouldn't be called if anything is onstack");
   400     MetadataFactory::free_metadata(loader_data, constants());
   401     set_constants(NULL);
   402   }
   404   if (inner_classes() != Universe::the_empty_short_array()) {
   405     MetadataFactory::free_array<jushort>(loader_data, inner_classes());
   406   }
   407   set_inner_classes(NULL);
   409   // We should deallocate the Annotations instance
   410   MetadataFactory::free_metadata(loader_data, annotations());
   411   set_annotations(NULL);
   412 }
   414 bool InstanceKlass::should_be_initialized() const {
   415   return !is_initialized();
   416 }
   418 klassVtable* InstanceKlass::vtable() const {
   419   return new klassVtable(this, start_of_vtable(), vtable_length() / vtableEntry::size());
   420 }
   422 klassItable* InstanceKlass::itable() const {
   423   return new klassItable(instanceKlassHandle(this));
   424 }
   426 void InstanceKlass::eager_initialize(Thread *thread) {
   427   if (!EagerInitialization) return;
   429   if (this->is_not_initialized()) {
   430     // abort if the the class has a class initializer
   431     if (this->class_initializer() != NULL) return;
   433     // abort if it is java.lang.Object (initialization is handled in genesis)
   434     Klass* super = this->super();
   435     if (super == NULL) return;
   437     // abort if the super class should be initialized
   438     if (!InstanceKlass::cast(super)->is_initialized()) return;
   440     // call body to expose the this pointer
   441     instanceKlassHandle this_oop(thread, this);
   442     eager_initialize_impl(this_oop);
   443   }
   444 }
   446 // JVMTI spec thinks there are signers and protection domain in the
   447 // instanceKlass.  These accessors pretend these fields are there.
   448 // The hprof specification also thinks these fields are in InstanceKlass.
   449 oop InstanceKlass::protection_domain() const {
   450   // return the protection_domain from the mirror
   451   return java_lang_Class::protection_domain(java_mirror());
   452 }
   454 // To remove these from requires an incompatible change and CCC request.
   455 objArrayOop InstanceKlass::signers() const {
   456   // return the signers from the mirror
   457   return java_lang_Class::signers(java_mirror());
   458 }
   460 volatile oop InstanceKlass::init_lock() const {
   461   // return the init lock from the mirror
   462   return java_lang_Class::init_lock(java_mirror());
   463 }
   465 void InstanceKlass::eager_initialize_impl(instanceKlassHandle this_oop) {
   466   EXCEPTION_MARK;
   467   volatile oop init_lock = this_oop->init_lock();
   468   ObjectLocker ol(init_lock, THREAD);
   470   // abort if someone beat us to the initialization
   471   if (!this_oop->is_not_initialized()) return;  // note: not equivalent to is_initialized()
   473   ClassState old_state = this_oop->init_state();
   474   link_class_impl(this_oop, true, THREAD);
   475   if (HAS_PENDING_EXCEPTION) {
   476     CLEAR_PENDING_EXCEPTION;
   477     // Abort if linking the class throws an exception.
   479     // Use a test to avoid redundantly resetting the state if there's
   480     // no change.  Set_init_state() asserts that state changes make
   481     // progress, whereas here we might just be spinning in place.
   482     if( old_state != this_oop->_init_state )
   483       this_oop->set_init_state (old_state);
   484   } else {
   485     // linking successfull, mark class as initialized
   486     this_oop->set_init_state (fully_initialized);
   487     // trace
   488     if (TraceClassInitialization) {
   489       ResourceMark rm(THREAD);
   490       tty->print_cr("[Initialized %s without side effects]", this_oop->external_name());
   491     }
   492   }
   493 }
   496 // See "The Virtual Machine Specification" section 2.16.5 for a detailed explanation of the class initialization
   497 // process. The step comments refers to the procedure described in that section.
   498 // Note: implementation moved to static method to expose the this pointer.
   499 void InstanceKlass::initialize(TRAPS) {
   500   if (this->should_be_initialized()) {
   501     HandleMark hm(THREAD);
   502     instanceKlassHandle this_oop(THREAD, this);
   503     initialize_impl(this_oop, CHECK);
   504     // Note: at this point the class may be initialized
   505     //       OR it may be in the state of being initialized
   506     //       in case of recursive initialization!
   507   } else {
   508     assert(is_initialized(), "sanity check");
   509   }
   510 }
   513 bool InstanceKlass::verify_code(
   514     instanceKlassHandle this_oop, bool throw_verifyerror, TRAPS) {
   515   // 1) Verify the bytecodes
   516   Verifier::Mode mode =
   517     throw_verifyerror ? Verifier::ThrowException : Verifier::NoException;
   518   return Verifier::verify(this_oop, mode, this_oop->should_verify_class(), CHECK_false);
   519 }
   522 // Used exclusively by the shared spaces dump mechanism to prevent
   523 // classes mapped into the shared regions in new VMs from appearing linked.
   525 void InstanceKlass::unlink_class() {
   526   assert(is_linked(), "must be linked");
   527   _init_state = loaded;
   528 }
   530 void InstanceKlass::link_class(TRAPS) {
   531   assert(is_loaded(), "must be loaded");
   532   if (!is_linked()) {
   533     HandleMark hm(THREAD);
   534     instanceKlassHandle this_oop(THREAD, this);
   535     link_class_impl(this_oop, true, CHECK);
   536   }
   537 }
   539 // Called to verify that a class can link during initialization, without
   540 // throwing a VerifyError.
   541 bool InstanceKlass::link_class_or_fail(TRAPS) {
   542   assert(is_loaded(), "must be loaded");
   543   if (!is_linked()) {
   544     HandleMark hm(THREAD);
   545     instanceKlassHandle this_oop(THREAD, this);
   546     link_class_impl(this_oop, false, CHECK_false);
   547   }
   548   return is_linked();
   549 }
   551 bool InstanceKlass::link_class_impl(
   552     instanceKlassHandle this_oop, bool throw_verifyerror, TRAPS) {
   553   // check for error state
   554   if (this_oop->is_in_error_state()) {
   555     ResourceMark rm(THREAD);
   556     THROW_MSG_(vmSymbols::java_lang_NoClassDefFoundError(),
   557                this_oop->external_name(), false);
   558   }
   559   // return if already verified
   560   if (this_oop->is_linked()) {
   561     return true;
   562   }
   564   // Timing
   565   // timer handles recursion
   566   assert(THREAD->is_Java_thread(), "non-JavaThread in link_class_impl");
   567   JavaThread* jt = (JavaThread*)THREAD;
   569   // link super class before linking this class
   570   instanceKlassHandle super(THREAD, this_oop->super());
   571   if (super.not_null()) {
   572     if (super->is_interface()) {  // check if super class is an interface
   573       ResourceMark rm(THREAD);
   574       Exceptions::fthrow(
   575         THREAD_AND_LOCATION,
   576         vmSymbols::java_lang_IncompatibleClassChangeError(),
   577         "class %s has interface %s as super class",
   578         this_oop->external_name(),
   579         super->external_name()
   580       );
   581       return false;
   582     }
   584     link_class_impl(super, throw_verifyerror, CHECK_false);
   585   }
   587   // link all interfaces implemented by this class before linking this class
   588   Array<Klass*>* interfaces = this_oop->local_interfaces();
   589   int num_interfaces = interfaces->length();
   590   for (int index = 0; index < num_interfaces; index++) {
   591     HandleMark hm(THREAD);
   592     instanceKlassHandle ih(THREAD, interfaces->at(index));
   593     link_class_impl(ih, throw_verifyerror, CHECK_false);
   594   }
   596   // in case the class is linked in the process of linking its superclasses
   597   if (this_oop->is_linked()) {
   598     return true;
   599   }
   601   // trace only the link time for this klass that includes
   602   // the verification time
   603   PerfClassTraceTime vmtimer(ClassLoader::perf_class_link_time(),
   604                              ClassLoader::perf_class_link_selftime(),
   605                              ClassLoader::perf_classes_linked(),
   606                              jt->get_thread_stat()->perf_recursion_counts_addr(),
   607                              jt->get_thread_stat()->perf_timers_addr(),
   608                              PerfClassTraceTime::CLASS_LINK);
   610   // verification & rewriting
   611   {
   612     volatile oop init_lock = this_oop->init_lock();
   613     ObjectLocker ol(init_lock, THREAD);
   614     // rewritten will have been set if loader constraint error found
   615     // on an earlier link attempt
   616     // don't verify or rewrite if already rewritten
   618     if (!this_oop->is_linked()) {
   619       if (!this_oop->is_rewritten()) {
   620         {
   621           // Timer includes any side effects of class verification (resolution,
   622           // etc), but not recursive entry into verify_code().
   623           PerfClassTraceTime timer(ClassLoader::perf_class_verify_time(),
   624                                    ClassLoader::perf_class_verify_selftime(),
   625                                    ClassLoader::perf_classes_verified(),
   626                                    jt->get_thread_stat()->perf_recursion_counts_addr(),
   627                                    jt->get_thread_stat()->perf_timers_addr(),
   628                                    PerfClassTraceTime::CLASS_VERIFY);
   629           bool verify_ok = verify_code(this_oop, throw_verifyerror, THREAD);
   630           if (!verify_ok) {
   631             return false;
   632           }
   633         }
   635         // Just in case a side-effect of verify linked this class already
   636         // (which can sometimes happen since the verifier loads classes
   637         // using custom class loaders, which are free to initialize things)
   638         if (this_oop->is_linked()) {
   639           return true;
   640         }
   642         // also sets rewritten
   643         this_oop->rewrite_class(CHECK_false);
   644       }
   646       // relocate jsrs and link methods after they are all rewritten
   647       this_oop->link_methods(CHECK_false);
   649       // Initialize the vtable and interface table after
   650       // methods have been rewritten since rewrite may
   651       // fabricate new Method*s.
   652       // also does loader constraint checking
   653       if (!this_oop()->is_shared()) {
   654         ResourceMark rm(THREAD);
   655         this_oop->vtable()->initialize_vtable(true, CHECK_false);
   656         this_oop->itable()->initialize_itable(true, CHECK_false);
   657       }
   658 #ifdef ASSERT
   659       else {
   660         ResourceMark rm(THREAD);
   661         this_oop->vtable()->verify(tty, true);
   662         // In case itable verification is ever added.
   663         // this_oop->itable()->verify(tty, true);
   664       }
   665 #endif
   666       this_oop->set_init_state(linked);
   667       if (JvmtiExport::should_post_class_prepare()) {
   668         Thread *thread = THREAD;
   669         assert(thread->is_Java_thread(), "thread->is_Java_thread()");
   670         JvmtiExport::post_class_prepare((JavaThread *) thread, this_oop());
   671       }
   672     }
   673   }
   674   return true;
   675 }
   678 // Rewrite the byte codes of all of the methods of a class.
   679 // The rewriter must be called exactly once. Rewriting must happen after
   680 // verification but before the first method of the class is executed.
   681 void InstanceKlass::rewrite_class(TRAPS) {
   682   assert(is_loaded(), "must be loaded");
   683   instanceKlassHandle this_oop(THREAD, this);
   684   if (this_oop->is_rewritten()) {
   685     assert(this_oop()->is_shared(), "rewriting an unshared class?");
   686     return;
   687   }
   688   Rewriter::rewrite(this_oop, CHECK);
   689   this_oop->set_rewritten();
   690 }
   692 // Now relocate and link method entry points after class is rewritten.
   693 // This is outside is_rewritten flag. In case of an exception, it can be
   694 // executed more than once.
   695 void InstanceKlass::link_methods(TRAPS) {
   696   int len = methods()->length();
   697   for (int i = len-1; i >= 0; i--) {
   698     methodHandle m(THREAD, methods()->at(i));
   700     // Set up method entry points for compiler and interpreter    .
   701     m->link_method(m, CHECK);
   703     // This is for JVMTI and unrelated to relocator but the last thing we do
   704 #ifdef ASSERT
   705     if (StressMethodComparator) {
   706       ResourceMark rm(THREAD);
   707       static int nmc = 0;
   708       for (int j = i; j >= 0 && j >= i-4; j--) {
   709         if ((++nmc % 1000) == 0)  tty->print_cr("Have run MethodComparator %d times...", nmc);
   710         bool z = MethodComparator::methods_EMCP(m(),
   711                    methods()->at(j));
   712         if (j == i && !z) {
   713           tty->print("MethodComparator FAIL: "); m->print(); m->print_codes();
   714           assert(z, "method must compare equal to itself");
   715         }
   716       }
   717     }
   718 #endif //ASSERT
   719   }
   720 }
   723 void InstanceKlass::initialize_impl(instanceKlassHandle this_oop, TRAPS) {
   724   // Make sure klass is linked (verified) before initialization
   725   // A class could already be verified, since it has been reflected upon.
   726   this_oop->link_class(CHECK);
   728   DTRACE_CLASSINIT_PROBE(required, InstanceKlass::cast(this_oop()), -1);
   730   bool wait = false;
   732   // refer to the JVM book page 47 for description of steps
   733   // Step 1
   734   {
   735     volatile oop init_lock = this_oop->init_lock();
   736     ObjectLocker ol(init_lock, THREAD);
   738     Thread *self = THREAD; // it's passed the current thread
   740     // Step 2
   741     // If we were to use wait() instead of waitInterruptibly() then
   742     // we might end up throwing IE from link/symbol resolution sites
   743     // that aren't expected to throw.  This would wreak havoc.  See 6320309.
   744     while(this_oop->is_being_initialized() && !this_oop->is_reentrant_initialization(self)) {
   745         wait = true;
   746       ol.waitUninterruptibly(CHECK);
   747     }
   749     // Step 3
   750     if (this_oop->is_being_initialized() && this_oop->is_reentrant_initialization(self)) {
   751       DTRACE_CLASSINIT_PROBE_WAIT(recursive, InstanceKlass::cast(this_oop()), -1,wait);
   752       return;
   753     }
   755     // Step 4
   756     if (this_oop->is_initialized()) {
   757       DTRACE_CLASSINIT_PROBE_WAIT(concurrent, InstanceKlass::cast(this_oop()), -1,wait);
   758       return;
   759     }
   761     // Step 5
   762     if (this_oop->is_in_error_state()) {
   763       DTRACE_CLASSINIT_PROBE_WAIT(erroneous, InstanceKlass::cast(this_oop()), -1,wait);
   764       ResourceMark rm(THREAD);
   765       const char* desc = "Could not initialize class ";
   766       const char* className = this_oop->external_name();
   767       size_t msglen = strlen(desc) + strlen(className) + 1;
   768       char* message = NEW_RESOURCE_ARRAY(char, msglen);
   769       if (NULL == message) {
   770         // Out of memory: can't create detailed error message
   771         THROW_MSG(vmSymbols::java_lang_NoClassDefFoundError(), className);
   772       } else {
   773         jio_snprintf(message, msglen, "%s%s", desc, className);
   774         THROW_MSG(vmSymbols::java_lang_NoClassDefFoundError(), message);
   775       }
   776     }
   778     // Step 6
   779     this_oop->set_init_state(being_initialized);
   780     this_oop->set_init_thread(self);
   781   }
   783   // Step 7
   784   Klass* super_klass = this_oop->super();
   785   if (super_klass != NULL && !this_oop->is_interface() && super_klass->should_be_initialized()) {
   786     super_klass->initialize(THREAD);
   788     if (HAS_PENDING_EXCEPTION) {
   789       Handle e(THREAD, PENDING_EXCEPTION);
   790       CLEAR_PENDING_EXCEPTION;
   791       {
   792         EXCEPTION_MARK;
   793         this_oop->set_initialization_state_and_notify(initialization_error, THREAD); // Locks object, set state, and notify all waiting threads
   794         CLEAR_PENDING_EXCEPTION;   // ignore any exception thrown, superclass initialization error is thrown below
   795       }
   796       DTRACE_CLASSINIT_PROBE_WAIT(super__failed, InstanceKlass::cast(this_oop()), -1,wait);
   797       THROW_OOP(e());
   798     }
   799   }
   801   if (this_oop->has_default_methods()) {
   802     // Step 7.5: initialize any interfaces which have default methods
   803     for (int i = 0; i < this_oop->local_interfaces()->length(); ++i) {
   804       Klass* iface = this_oop->local_interfaces()->at(i);
   805       InstanceKlass* ik = InstanceKlass::cast(iface);
   806       if (ik->has_default_methods() && ik->should_be_initialized()) {
   807         ik->initialize(THREAD);
   809         if (HAS_PENDING_EXCEPTION) {
   810           Handle e(THREAD, PENDING_EXCEPTION);
   811           CLEAR_PENDING_EXCEPTION;
   812           {
   813             EXCEPTION_MARK;
   814             // Locks object, set state, and notify all waiting threads
   815             this_oop->set_initialization_state_and_notify(
   816                 initialization_error, THREAD);
   818             // ignore any exception thrown, superclass initialization error is
   819             // thrown below
   820             CLEAR_PENDING_EXCEPTION;
   821           }
   822           DTRACE_CLASSINIT_PROBE_WAIT(
   823               super__failed, InstanceKlass::cast(this_oop()), -1, wait);
   824           THROW_OOP(e());
   825         }
   826       }
   827     }
   828   }
   830   // Step 8
   831   {
   832     assert(THREAD->is_Java_thread(), "non-JavaThread in initialize_impl");
   833     JavaThread* jt = (JavaThread*)THREAD;
   834     DTRACE_CLASSINIT_PROBE_WAIT(clinit, InstanceKlass::cast(this_oop()), -1,wait);
   835     // Timer includes any side effects of class initialization (resolution,
   836     // etc), but not recursive entry into call_class_initializer().
   837     PerfClassTraceTime timer(ClassLoader::perf_class_init_time(),
   838                              ClassLoader::perf_class_init_selftime(),
   839                              ClassLoader::perf_classes_inited(),
   840                              jt->get_thread_stat()->perf_recursion_counts_addr(),
   841                              jt->get_thread_stat()->perf_timers_addr(),
   842                              PerfClassTraceTime::CLASS_CLINIT);
   843     this_oop->call_class_initializer(THREAD);
   844   }
   846   // Step 9
   847   if (!HAS_PENDING_EXCEPTION) {
   848     this_oop->set_initialization_state_and_notify(fully_initialized, CHECK);
   849     { ResourceMark rm(THREAD);
   850       debug_only(this_oop->vtable()->verify(tty, true);)
   851     }
   852   }
   853   else {
   854     // Step 10 and 11
   855     Handle e(THREAD, PENDING_EXCEPTION);
   856     CLEAR_PENDING_EXCEPTION;
   857     {
   858       EXCEPTION_MARK;
   859       this_oop->set_initialization_state_and_notify(initialization_error, THREAD);
   860       CLEAR_PENDING_EXCEPTION;   // ignore any exception thrown, class initialization error is thrown below
   861     }
   862     DTRACE_CLASSINIT_PROBE_WAIT(error, InstanceKlass::cast(this_oop()), -1,wait);
   863     if (e->is_a(SystemDictionary::Error_klass())) {
   864       THROW_OOP(e());
   865     } else {
   866       JavaCallArguments args(e);
   867       THROW_ARG(vmSymbols::java_lang_ExceptionInInitializerError(),
   868                 vmSymbols::throwable_void_signature(),
   869                 &args);
   870     }
   871   }
   872   DTRACE_CLASSINIT_PROBE_WAIT(end, InstanceKlass::cast(this_oop()), -1,wait);
   873 }
   876 // Note: implementation moved to static method to expose the this pointer.
   877 void InstanceKlass::set_initialization_state_and_notify(ClassState state, TRAPS) {
   878   instanceKlassHandle kh(THREAD, this);
   879   set_initialization_state_and_notify_impl(kh, state, CHECK);
   880 }
   882 void InstanceKlass::set_initialization_state_and_notify_impl(instanceKlassHandle this_oop, ClassState state, TRAPS) {
   883   volatile oop init_lock = this_oop->init_lock();
   884   ObjectLocker ol(init_lock, THREAD);
   885   this_oop->set_init_state(state);
   886   ol.notify_all(CHECK);
   887 }
   889 // The embedded _implementor field can only record one implementor.
   890 // When there are more than one implementors, the _implementor field
   891 // is set to the interface Klass* itself. Following are the possible
   892 // values for the _implementor field:
   893 //   NULL                  - no implementor
   894 //   implementor Klass*    - one implementor
   895 //   self                  - more than one implementor
   896 //
   897 // The _implementor field only exists for interfaces.
   898 void InstanceKlass::add_implementor(Klass* k) {
   899   assert(Compile_lock->owned_by_self(), "");
   900   assert(is_interface(), "not interface");
   901   // Filter out my subinterfaces.
   902   // (Note: Interfaces are never on the subklass list.)
   903   if (InstanceKlass::cast(k)->is_interface()) return;
   905   // Filter out subclasses whose supers already implement me.
   906   // (Note: CHA must walk subclasses of direct implementors
   907   // in order to locate indirect implementors.)
   908   Klass* sk = InstanceKlass::cast(k)->super();
   909   if (sk != NULL && InstanceKlass::cast(sk)->implements_interface(this))
   910     // We only need to check one immediate superclass, since the
   911     // implements_interface query looks at transitive_interfaces.
   912     // Any supers of the super have the same (or fewer) transitive_interfaces.
   913     return;
   915   Klass* ik = implementor();
   916   if (ik == NULL) {
   917     set_implementor(k);
   918   } else if (ik != this) {
   919     // There is already an implementor. Use itself as an indicator of
   920     // more than one implementors.
   921     set_implementor(this);
   922   }
   924   // The implementor also implements the transitive_interfaces
   925   for (int index = 0; index < local_interfaces()->length(); index++) {
   926     InstanceKlass::cast(local_interfaces()->at(index))->add_implementor(k);
   927   }
   928 }
   930 void InstanceKlass::init_implementor() {
   931   if (is_interface()) {
   932     set_implementor(NULL);
   933   }
   934 }
   937 void InstanceKlass::process_interfaces(Thread *thread) {
   938   // link this class into the implementors list of every interface it implements
   939   Klass* this_as_klass_oop = this;
   940   for (int i = local_interfaces()->length() - 1; i >= 0; i--) {
   941     assert(local_interfaces()->at(i)->is_klass(), "must be a klass");
   942     InstanceKlass* interf = InstanceKlass::cast(local_interfaces()->at(i));
   943     assert(interf->is_interface(), "expected interface");
   944     interf->add_implementor(this_as_klass_oop);
   945   }
   946 }
   948 bool InstanceKlass::can_be_primary_super_slow() const {
   949   if (is_interface())
   950     return false;
   951   else
   952     return Klass::can_be_primary_super_slow();
   953 }
   955 GrowableArray<Klass*>* InstanceKlass::compute_secondary_supers(int num_extra_slots) {
   956   // The secondaries are the implemented interfaces.
   957   InstanceKlass* ik = InstanceKlass::cast(this);
   958   Array<Klass*>* interfaces = ik->transitive_interfaces();
   959   int num_secondaries = num_extra_slots + interfaces->length();
   960   if (num_secondaries == 0) {
   961     // Must share this for correct bootstrapping!
   962     set_secondary_supers(Universe::the_empty_klass_array());
   963     return NULL;
   964   } else if (num_extra_slots == 0) {
   965     // The secondary super list is exactly the same as the transitive interfaces.
   966     // Redefine classes has to be careful not to delete this!
   967     set_secondary_supers(interfaces);
   968     return NULL;
   969   } else {
   970     // Copy transitive interfaces to a temporary growable array to be constructed
   971     // into the secondary super list with extra slots.
   972     GrowableArray<Klass*>* secondaries = new GrowableArray<Klass*>(interfaces->length());
   973     for (int i = 0; i < interfaces->length(); i++) {
   974       secondaries->push(interfaces->at(i));
   975     }
   976     return secondaries;
   977   }
   978 }
   980 bool InstanceKlass::compute_is_subtype_of(Klass* k) {
   981   if (k->is_interface()) {
   982     return implements_interface(k);
   983   } else {
   984     return Klass::compute_is_subtype_of(k);
   985   }
   986 }
   988 bool InstanceKlass::implements_interface(Klass* k) const {
   989   if (this == k) return true;
   990   assert(k->is_interface(), "should be an interface class");
   991   for (int i = 0; i < transitive_interfaces()->length(); i++) {
   992     if (transitive_interfaces()->at(i) == k) {
   993       return true;
   994     }
   995   }
   996   return false;
   997 }
   999 objArrayOop InstanceKlass::allocate_objArray(int n, int length, TRAPS) {
  1000   if (length < 0) THROW_0(vmSymbols::java_lang_NegativeArraySizeException());
  1001   if (length > arrayOopDesc::max_array_length(T_OBJECT)) {
  1002     report_java_out_of_memory("Requested array size exceeds VM limit");
  1003     JvmtiExport::post_array_size_exhausted();
  1004     THROW_OOP_0(Universe::out_of_memory_error_array_size());
  1006   int size = objArrayOopDesc::object_size(length);
  1007   Klass* ak = array_klass(n, CHECK_NULL);
  1008   KlassHandle h_ak (THREAD, ak);
  1009   objArrayOop o =
  1010     (objArrayOop)CollectedHeap::array_allocate(h_ak, size, length, CHECK_NULL);
  1011   return o;
  1014 instanceOop InstanceKlass::register_finalizer(instanceOop i, TRAPS) {
  1015   if (TraceFinalizerRegistration) {
  1016     tty->print("Registered ");
  1017     i->print_value_on(tty);
  1018     tty->print_cr(" (" INTPTR_FORMAT ") as finalizable", (address)i);
  1020   instanceHandle h_i(THREAD, i);
  1021   // Pass the handle as argument, JavaCalls::call expects oop as jobjects
  1022   JavaValue result(T_VOID);
  1023   JavaCallArguments args(h_i);
  1024   methodHandle mh (THREAD, Universe::finalizer_register_method());
  1025   JavaCalls::call(&result, mh, &args, CHECK_NULL);
  1026   return h_i();
  1029 instanceOop InstanceKlass::allocate_instance(TRAPS) {
  1030   bool has_finalizer_flag = has_finalizer(); // Query before possible GC
  1031   int size = size_helper();  // Query before forming handle.
  1033   KlassHandle h_k(THREAD, this);
  1035   instanceOop i;
  1037   i = (instanceOop)CollectedHeap::obj_allocate(h_k, size, CHECK_NULL);
  1038   if (has_finalizer_flag && !RegisterFinalizersAtInit) {
  1039     i = register_finalizer(i, CHECK_NULL);
  1041   return i;
  1044 void InstanceKlass::check_valid_for_instantiation(bool throwError, TRAPS) {
  1045   if (is_interface() || is_abstract()) {
  1046     ResourceMark rm(THREAD);
  1047     THROW_MSG(throwError ? vmSymbols::java_lang_InstantiationError()
  1048               : vmSymbols::java_lang_InstantiationException(), external_name());
  1050   if (this == SystemDictionary::Class_klass()) {
  1051     ResourceMark rm(THREAD);
  1052     THROW_MSG(throwError ? vmSymbols::java_lang_IllegalAccessError()
  1053               : vmSymbols::java_lang_IllegalAccessException(), external_name());
  1057 Klass* InstanceKlass::array_klass_impl(bool or_null, int n, TRAPS) {
  1058   instanceKlassHandle this_oop(THREAD, this);
  1059   return array_klass_impl(this_oop, or_null, n, THREAD);
  1062 Klass* InstanceKlass::array_klass_impl(instanceKlassHandle this_oop, bool or_null, int n, TRAPS) {
  1063   if (this_oop->array_klasses() == NULL) {
  1064     if (or_null) return NULL;
  1066     ResourceMark rm;
  1067     JavaThread *jt = (JavaThread *)THREAD;
  1069       // Atomic creation of array_klasses
  1070       MutexLocker mc(Compile_lock, THREAD);   // for vtables
  1071       MutexLocker ma(MultiArray_lock, THREAD);
  1073       // Check if update has already taken place
  1074       if (this_oop->array_klasses() == NULL) {
  1075         Klass*    k = ObjArrayKlass::allocate_objArray_klass(this_oop->class_loader_data(), 1, this_oop, CHECK_NULL);
  1076         this_oop->set_array_klasses(k);
  1080   // _this will always be set at this point
  1081   ObjArrayKlass* oak = (ObjArrayKlass*)this_oop->array_klasses();
  1082   if (or_null) {
  1083     return oak->array_klass_or_null(n);
  1085   return oak->array_klass(n, CHECK_NULL);
  1088 Klass* InstanceKlass::array_klass_impl(bool or_null, TRAPS) {
  1089   return array_klass_impl(or_null, 1, THREAD);
  1092 void InstanceKlass::call_class_initializer(TRAPS) {
  1093   instanceKlassHandle ik (THREAD, this);
  1094   call_class_initializer_impl(ik, THREAD);
  1097 static int call_class_initializer_impl_counter = 0;   // for debugging
  1099 Method* InstanceKlass::class_initializer() {
  1100   Method* clinit = find_method(
  1101       vmSymbols::class_initializer_name(), vmSymbols::void_method_signature());
  1102   if (clinit != NULL && clinit->has_valid_initializer_flags()) {
  1103     return clinit;
  1105   return NULL;
  1108 void InstanceKlass::call_class_initializer_impl(instanceKlassHandle this_oop, TRAPS) {
  1109   if (ReplayCompiles &&
  1110       (ReplaySuppressInitializers == 1 ||
  1111        ReplaySuppressInitializers >= 2 && this_oop->class_loader() != NULL)) {
  1112     // Hide the existence of the initializer for the purpose of replaying the compile
  1113     return;
  1116   methodHandle h_method(THREAD, this_oop->class_initializer());
  1117   assert(!this_oop->is_initialized(), "we cannot initialize twice");
  1118   if (TraceClassInitialization) {
  1119     tty->print("%d Initializing ", call_class_initializer_impl_counter++);
  1120     this_oop->name()->print_value();
  1121     tty->print_cr("%s (" INTPTR_FORMAT ")", h_method() == NULL ? "(no method)" : "", (address)this_oop());
  1123   if (h_method() != NULL) {
  1124     JavaCallArguments args; // No arguments
  1125     JavaValue result(T_VOID);
  1126     JavaCalls::call(&result, h_method, &args, CHECK); // Static call (no args)
  1131 void InstanceKlass::mask_for(methodHandle method, int bci,
  1132   InterpreterOopMap* entry_for) {
  1133   // Dirty read, then double-check under a lock.
  1134   if (_oop_map_cache == NULL) {
  1135     // Otherwise, allocate a new one.
  1136     MutexLocker x(OopMapCacheAlloc_lock);
  1137     // First time use. Allocate a cache in C heap
  1138     if (_oop_map_cache == NULL) {
  1139       _oop_map_cache = new OopMapCache();
  1142   // _oop_map_cache is constant after init; lookup below does is own locking.
  1143   _oop_map_cache->lookup(method, bci, entry_for);
  1147 bool InstanceKlass::find_local_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
  1148   for (JavaFieldStream fs(this); !fs.done(); fs.next()) {
  1149     Symbol* f_name = fs.name();
  1150     Symbol* f_sig  = fs.signature();
  1151     if (f_name == name && f_sig == sig) {
  1152       fd->initialize(const_cast<InstanceKlass*>(this), fs.index());
  1153       return true;
  1156   return false;
  1160 Klass* InstanceKlass::find_interface_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
  1161   const int n = local_interfaces()->length();
  1162   for (int i = 0; i < n; i++) {
  1163     Klass* intf1 = local_interfaces()->at(i);
  1164     assert(intf1->is_interface(), "just checking type");
  1165     // search for field in current interface
  1166     if (InstanceKlass::cast(intf1)->find_local_field(name, sig, fd)) {
  1167       assert(fd->is_static(), "interface field must be static");
  1168       return intf1;
  1170     // search for field in direct superinterfaces
  1171     Klass* intf2 = InstanceKlass::cast(intf1)->find_interface_field(name, sig, fd);
  1172     if (intf2 != NULL) return intf2;
  1174   // otherwise field lookup fails
  1175   return NULL;
  1179 Klass* InstanceKlass::find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const {
  1180   // search order according to newest JVM spec (5.4.3.2, p.167).
  1181   // 1) search for field in current klass
  1182   if (find_local_field(name, sig, fd)) {
  1183     return const_cast<InstanceKlass*>(this);
  1185   // 2) search for field recursively in direct superinterfaces
  1186   { Klass* intf = find_interface_field(name, sig, fd);
  1187     if (intf != NULL) return intf;
  1189   // 3) apply field lookup recursively if superclass exists
  1190   { Klass* supr = super();
  1191     if (supr != NULL) return InstanceKlass::cast(supr)->find_field(name, sig, fd);
  1193   // 4) otherwise field lookup fails
  1194   return NULL;
  1198 Klass* InstanceKlass::find_field(Symbol* name, Symbol* sig, bool is_static, fieldDescriptor* fd) const {
  1199   // search order according to newest JVM spec (5.4.3.2, p.167).
  1200   // 1) search for field in current klass
  1201   if (find_local_field(name, sig, fd)) {
  1202     if (fd->is_static() == is_static) return const_cast<InstanceKlass*>(this);
  1204   // 2) search for field recursively in direct superinterfaces
  1205   if (is_static) {
  1206     Klass* intf = find_interface_field(name, sig, fd);
  1207     if (intf != NULL) return intf;
  1209   // 3) apply field lookup recursively if superclass exists
  1210   { Klass* supr = super();
  1211     if (supr != NULL) return InstanceKlass::cast(supr)->find_field(name, sig, is_static, fd);
  1213   // 4) otherwise field lookup fails
  1214   return NULL;
  1218 bool InstanceKlass::find_local_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const {
  1219   for (JavaFieldStream fs(this); !fs.done(); fs.next()) {
  1220     if (fs.offset() == offset) {
  1221       fd->initialize(const_cast<InstanceKlass*>(this), fs.index());
  1222       if (fd->is_static() == is_static) return true;
  1225   return false;
  1229 bool InstanceKlass::find_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const {
  1230   Klass* klass = const_cast<InstanceKlass*>(this);
  1231   while (klass != NULL) {
  1232     if (InstanceKlass::cast(klass)->find_local_field_from_offset(offset, is_static, fd)) {
  1233       return true;
  1235     klass = klass->super();
  1237   return false;
  1241 void InstanceKlass::methods_do(void f(Method* method)) {
  1242   int len = methods()->length();
  1243   for (int index = 0; index < len; index++) {
  1244     Method* m = methods()->at(index);
  1245     assert(m->is_method(), "must be method");
  1246     f(m);
  1251 void InstanceKlass::do_local_static_fields(FieldClosure* cl) {
  1252   for (JavaFieldStream fs(this); !fs.done(); fs.next()) {
  1253     if (fs.access_flags().is_static()) {
  1254       fieldDescriptor fd;
  1255       fd.initialize(this, fs.index());
  1256       cl->do_field(&fd);
  1262 void InstanceKlass::do_local_static_fields(void f(fieldDescriptor*, TRAPS), TRAPS) {
  1263   instanceKlassHandle h_this(THREAD, this);
  1264   do_local_static_fields_impl(h_this, f, CHECK);
  1268 void InstanceKlass::do_local_static_fields_impl(instanceKlassHandle this_oop, void f(fieldDescriptor* fd, TRAPS), TRAPS) {
  1269   for (JavaFieldStream fs(this_oop()); !fs.done(); fs.next()) {
  1270     if (fs.access_flags().is_static()) {
  1271       fieldDescriptor fd;
  1272       fd.initialize(this_oop(), fs.index());
  1273       f(&fd, CHECK);
  1279 static int compare_fields_by_offset(int* a, int* b) {
  1280   return a[0] - b[0];
  1283 void InstanceKlass::do_nonstatic_fields(FieldClosure* cl) {
  1284   InstanceKlass* super = superklass();
  1285   if (super != NULL) {
  1286     super->do_nonstatic_fields(cl);
  1288   fieldDescriptor fd;
  1289   int length = java_fields_count();
  1290   // In DebugInfo nonstatic fields are sorted by offset.
  1291   int* fields_sorted = NEW_C_HEAP_ARRAY(int, 2*(length+1), mtClass);
  1292   int j = 0;
  1293   for (int i = 0; i < length; i += 1) {
  1294     fd.initialize(this, i);
  1295     if (!fd.is_static()) {
  1296       fields_sorted[j + 0] = fd.offset();
  1297       fields_sorted[j + 1] = i;
  1298       j += 2;
  1301   if (j > 0) {
  1302     length = j;
  1303     // _sort_Fn is defined in growableArray.hpp.
  1304     qsort(fields_sorted, length/2, 2*sizeof(int), (_sort_Fn)compare_fields_by_offset);
  1305     for (int i = 0; i < length; i += 2) {
  1306       fd.initialize(this, fields_sorted[i + 1]);
  1307       assert(!fd.is_static() && fd.offset() == fields_sorted[i], "only nonstatic fields");
  1308       cl->do_field(&fd);
  1311   FREE_C_HEAP_ARRAY(int, fields_sorted, mtClass);
  1315 void InstanceKlass::array_klasses_do(void f(Klass* k, TRAPS), TRAPS) {
  1316   if (array_klasses() != NULL)
  1317     ArrayKlass::cast(array_klasses())->array_klasses_do(f, THREAD);
  1320 void InstanceKlass::array_klasses_do(void f(Klass* k)) {
  1321   if (array_klasses() != NULL)
  1322     ArrayKlass::cast(array_klasses())->array_klasses_do(f);
  1325 #ifdef ASSERT
  1326 static int linear_search(Array<Method*>* methods, Symbol* name, Symbol* signature) {
  1327   int len = methods->length();
  1328   for (int index = 0; index < len; index++) {
  1329     Method* m = methods->at(index);
  1330     assert(m->is_method(), "must be method");
  1331     if (m->signature() == signature && m->name() == name) {
  1332        return index;
  1335   return -1;
  1337 #endif
  1339 static int binary_search(Array<Method*>* methods, Symbol* name) {
  1340   int len = methods->length();
  1341   // methods are sorted, so do binary search
  1342   int l = 0;
  1343   int h = len - 1;
  1344   while (l <= h) {
  1345     int mid = (l + h) >> 1;
  1346     Method* m = methods->at(mid);
  1347     assert(m->is_method(), "must be method");
  1348     int res = m->name()->fast_compare(name);
  1349     if (res == 0) {
  1350       return mid;
  1351     } else if (res < 0) {
  1352       l = mid + 1;
  1353     } else {
  1354       h = mid - 1;
  1357   return -1;
  1360 Method* InstanceKlass::find_method(Symbol* name, Symbol* signature) const {
  1361   return InstanceKlass::find_method(methods(), name, signature);
  1364 Method* InstanceKlass::find_method(
  1365     Array<Method*>* methods, Symbol* name, Symbol* signature) {
  1366   int hit = binary_search(methods, name);
  1367   if (hit != -1) {
  1368     Method* m = methods->at(hit);
  1369     // Do linear search to find matching signature.  First, quick check
  1370     // for common case
  1371     if (m->signature() == signature) return m;
  1372     // search downwards through overloaded methods
  1373     int i;
  1374     for (i = hit - 1; i >= 0; --i) {
  1375         Method* m = methods->at(i);
  1376         assert(m->is_method(), "must be method");
  1377         if (m->name() != name) break;
  1378         if (m->signature() == signature) return m;
  1380     // search upwards
  1381     for (i = hit + 1; i < methods->length(); ++i) {
  1382         Method* m = methods->at(i);
  1383         assert(m->is_method(), "must be method");
  1384         if (m->name() != name) break;
  1385         if (m->signature() == signature) return m;
  1387     // not found
  1388 #ifdef ASSERT
  1389     int index = linear_search(methods, name, signature);
  1390     assert(index == -1, err_msg("binary search should have found entry %d", index));
  1391 #endif
  1393   return NULL;
  1396 int InstanceKlass::find_method_by_name(Symbol* name, int* end) {
  1397   return find_method_by_name(methods(), name, end);
  1400 int InstanceKlass::find_method_by_name(
  1401     Array<Method*>* methods, Symbol* name, int* end_ptr) {
  1402   assert(end_ptr != NULL, "just checking");
  1403   int start = binary_search(methods, name);
  1404   int end = start + 1;
  1405   if (start != -1) {
  1406     while (start - 1 >= 0 && (methods->at(start - 1))->name() == name) --start;
  1407     while (end < methods->length() && (methods->at(end))->name() == name) ++end;
  1408     *end_ptr = end;
  1409     return start;
  1411   return -1;
  1414 Method* InstanceKlass::uncached_lookup_method(Symbol* name, Symbol* signature) const {
  1415   Klass* klass = const_cast<InstanceKlass*>(this);
  1416   while (klass != NULL) {
  1417     Method* method = InstanceKlass::cast(klass)->find_method(name, signature);
  1418     if (method != NULL) return method;
  1419     klass = InstanceKlass::cast(klass)->super();
  1421   return NULL;
  1424 // lookup a method in all the interfaces that this class implements
  1425 Method* InstanceKlass::lookup_method_in_all_interfaces(Symbol* name,
  1426                                                          Symbol* signature) const {
  1427   Array<Klass*>* all_ifs = transitive_interfaces();
  1428   int num_ifs = all_ifs->length();
  1429   InstanceKlass *ik = NULL;
  1430   for (int i = 0; i < num_ifs; i++) {
  1431     ik = InstanceKlass::cast(all_ifs->at(i));
  1432     Method* m = ik->lookup_method(name, signature);
  1433     if (m != NULL) {
  1434       return m;
  1437   return NULL;
  1440 /* jni_id_for_impl for jfieldIds only */
  1441 JNIid* InstanceKlass::jni_id_for_impl(instanceKlassHandle this_oop, int offset) {
  1442   MutexLocker ml(JfieldIdCreation_lock);
  1443   // Retry lookup after we got the lock
  1444   JNIid* probe = this_oop->jni_ids() == NULL ? NULL : this_oop->jni_ids()->find(offset);
  1445   if (probe == NULL) {
  1446     // Slow case, allocate new static field identifier
  1447     probe = new JNIid(this_oop(), offset, this_oop->jni_ids());
  1448     this_oop->set_jni_ids(probe);
  1450   return probe;
  1454 /* jni_id_for for jfieldIds only */
  1455 JNIid* InstanceKlass::jni_id_for(int offset) {
  1456   JNIid* probe = jni_ids() == NULL ? NULL : jni_ids()->find(offset);
  1457   if (probe == NULL) {
  1458     probe = jni_id_for_impl(this, offset);
  1460   return probe;
  1463 u2 InstanceKlass::enclosing_method_data(int offset) {
  1464   Array<jushort>* inner_class_list = inner_classes();
  1465   if (inner_class_list == NULL) {
  1466     return 0;
  1468   int length = inner_class_list->length();
  1469   if (length % inner_class_next_offset == 0) {
  1470     return 0;
  1471   } else {
  1472     int index = length - enclosing_method_attribute_size;
  1473     assert(offset < enclosing_method_attribute_size, "invalid offset");
  1474     return inner_class_list->at(index + offset);
  1478 void InstanceKlass::set_enclosing_method_indices(u2 class_index,
  1479                                                  u2 method_index) {
  1480   Array<jushort>* inner_class_list = inner_classes();
  1481   assert (inner_class_list != NULL, "_inner_classes list is not set up");
  1482   int length = inner_class_list->length();
  1483   if (length % inner_class_next_offset == enclosing_method_attribute_size) {
  1484     int index = length - enclosing_method_attribute_size;
  1485     inner_class_list->at_put(
  1486       index + enclosing_method_class_index_offset, class_index);
  1487     inner_class_list->at_put(
  1488       index + enclosing_method_method_index_offset, method_index);
  1492 // Lookup or create a jmethodID.
  1493 // This code is called by the VMThread and JavaThreads so the
  1494 // locking has to be done very carefully to avoid deadlocks
  1495 // and/or other cache consistency problems.
  1496 //
  1497 jmethodID InstanceKlass::get_jmethod_id(instanceKlassHandle ik_h, methodHandle method_h) {
  1498   size_t idnum = (size_t)method_h->method_idnum();
  1499   jmethodID* jmeths = ik_h->methods_jmethod_ids_acquire();
  1500   size_t length = 0;
  1501   jmethodID id = NULL;
  1503   // We use a double-check locking idiom here because this cache is
  1504   // performance sensitive. In the normal system, this cache only
  1505   // transitions from NULL to non-NULL which is safe because we use
  1506   // release_set_methods_jmethod_ids() to advertise the new cache.
  1507   // A partially constructed cache should never be seen by a racing
  1508   // thread. We also use release_store_ptr() to save a new jmethodID
  1509   // in the cache so a partially constructed jmethodID should never be
  1510   // seen either. Cache reads of existing jmethodIDs proceed without a
  1511   // lock, but cache writes of a new jmethodID requires uniqueness and
  1512   // creation of the cache itself requires no leaks so a lock is
  1513   // generally acquired in those two cases.
  1514   //
  1515   // If the RedefineClasses() API has been used, then this cache can
  1516   // grow and we'll have transitions from non-NULL to bigger non-NULL.
  1517   // Cache creation requires no leaks and we require safety between all
  1518   // cache accesses and freeing of the old cache so a lock is generally
  1519   // acquired when the RedefineClasses() API has been used.
  1521   if (jmeths != NULL) {
  1522     // the cache already exists
  1523     if (!ik_h->idnum_can_increment()) {
  1524       // the cache can't grow so we can just get the current values
  1525       get_jmethod_id_length_value(jmeths, idnum, &length, &id);
  1526     } else {
  1527       // cache can grow so we have to be more careful
  1528       if (Threads::number_of_threads() == 0 ||
  1529           SafepointSynchronize::is_at_safepoint()) {
  1530         // we're single threaded or at a safepoint - no locking needed
  1531         get_jmethod_id_length_value(jmeths, idnum, &length, &id);
  1532       } else {
  1533         MutexLocker ml(JmethodIdCreation_lock);
  1534         get_jmethod_id_length_value(jmeths, idnum, &length, &id);
  1538   // implied else:
  1539   // we need to allocate a cache so default length and id values are good
  1541   if (jmeths == NULL ||   // no cache yet
  1542       length <= idnum ||  // cache is too short
  1543       id == NULL) {       // cache doesn't contain entry
  1545     // This function can be called by the VMThread so we have to do all
  1546     // things that might block on a safepoint before grabbing the lock.
  1547     // Otherwise, we can deadlock with the VMThread or have a cache
  1548     // consistency issue. These vars keep track of what we might have
  1549     // to free after the lock is dropped.
  1550     jmethodID  to_dealloc_id     = NULL;
  1551     jmethodID* to_dealloc_jmeths = NULL;
  1553     // may not allocate new_jmeths or use it if we allocate it
  1554     jmethodID* new_jmeths = NULL;
  1555     if (length <= idnum) {
  1556       // allocate a new cache that might be used
  1557       size_t size = MAX2(idnum+1, (size_t)ik_h->idnum_allocated_count());
  1558       new_jmeths = NEW_C_HEAP_ARRAY(jmethodID, size+1, mtClass);
  1559       memset(new_jmeths, 0, (size+1)*sizeof(jmethodID));
  1560       // cache size is stored in element[0], other elements offset by one
  1561       new_jmeths[0] = (jmethodID)size;
  1564     // allocate a new jmethodID that might be used
  1565     jmethodID new_id = NULL;
  1566     if (method_h->is_old() && !method_h->is_obsolete()) {
  1567       // The method passed in is old (but not obsolete), we need to use the current version
  1568       Method* current_method = ik_h->method_with_idnum((int)idnum);
  1569       assert(current_method != NULL, "old and but not obsolete, so should exist");
  1570       new_id = Method::make_jmethod_id(ik_h->class_loader_data(), current_method);
  1571     } else {
  1572       // It is the current version of the method or an obsolete method,
  1573       // use the version passed in
  1574       new_id = Method::make_jmethod_id(ik_h->class_loader_data(), method_h());
  1577     if (Threads::number_of_threads() == 0 ||
  1578         SafepointSynchronize::is_at_safepoint()) {
  1579       // we're single threaded or at a safepoint - no locking needed
  1580       id = get_jmethod_id_fetch_or_update(ik_h, idnum, new_id, new_jmeths,
  1581                                           &to_dealloc_id, &to_dealloc_jmeths);
  1582     } else {
  1583       MutexLocker ml(JmethodIdCreation_lock);
  1584       id = get_jmethod_id_fetch_or_update(ik_h, idnum, new_id, new_jmeths,
  1585                                           &to_dealloc_id, &to_dealloc_jmeths);
  1588     // The lock has been dropped so we can free resources.
  1589     // Free up either the old cache or the new cache if we allocated one.
  1590     if (to_dealloc_jmeths != NULL) {
  1591       FreeHeap(to_dealloc_jmeths);
  1593     // free up the new ID since it wasn't needed
  1594     if (to_dealloc_id != NULL) {
  1595       Method::destroy_jmethod_id(ik_h->class_loader_data(), to_dealloc_id);
  1598   return id;
  1602 // Common code to fetch the jmethodID from the cache or update the
  1603 // cache with the new jmethodID. This function should never do anything
  1604 // that causes the caller to go to a safepoint or we can deadlock with
  1605 // the VMThread or have cache consistency issues.
  1606 //
  1607 jmethodID InstanceKlass::get_jmethod_id_fetch_or_update(
  1608             instanceKlassHandle ik_h, size_t idnum, jmethodID new_id,
  1609             jmethodID* new_jmeths, jmethodID* to_dealloc_id_p,
  1610             jmethodID** to_dealloc_jmeths_p) {
  1611   assert(new_id != NULL, "sanity check");
  1612   assert(to_dealloc_id_p != NULL, "sanity check");
  1613   assert(to_dealloc_jmeths_p != NULL, "sanity check");
  1614   assert(Threads::number_of_threads() == 0 ||
  1615          SafepointSynchronize::is_at_safepoint() ||
  1616          JmethodIdCreation_lock->owned_by_self(), "sanity check");
  1618   // reacquire the cache - we are locked, single threaded or at a safepoint
  1619   jmethodID* jmeths = ik_h->methods_jmethod_ids_acquire();
  1620   jmethodID  id     = NULL;
  1621   size_t     length = 0;
  1623   if (jmeths == NULL ||                         // no cache yet
  1624       (length = (size_t)jmeths[0]) <= idnum) {  // cache is too short
  1625     if (jmeths != NULL) {
  1626       // copy any existing entries from the old cache
  1627       for (size_t index = 0; index < length; index++) {
  1628         new_jmeths[index+1] = jmeths[index+1];
  1630       *to_dealloc_jmeths_p = jmeths;  // save old cache for later delete
  1632     ik_h->release_set_methods_jmethod_ids(jmeths = new_jmeths);
  1633   } else {
  1634     // fetch jmethodID (if any) from the existing cache
  1635     id = jmeths[idnum+1];
  1636     *to_dealloc_jmeths_p = new_jmeths;  // save new cache for later delete
  1638   if (id == NULL) {
  1639     // No matching jmethodID in the existing cache or we have a new
  1640     // cache or we just grew the cache. This cache write is done here
  1641     // by the first thread to win the foot race because a jmethodID
  1642     // needs to be unique once it is generally available.
  1643     id = new_id;
  1645     // The jmethodID cache can be read while unlocked so we have to
  1646     // make sure the new jmethodID is complete before installing it
  1647     // in the cache.
  1648     OrderAccess::release_store_ptr(&jmeths[idnum+1], id);
  1649   } else {
  1650     *to_dealloc_id_p = new_id; // save new id for later delete
  1652   return id;
  1656 // Common code to get the jmethodID cache length and the jmethodID
  1657 // value at index idnum if there is one.
  1658 //
  1659 void InstanceKlass::get_jmethod_id_length_value(jmethodID* cache,
  1660        size_t idnum, size_t *length_p, jmethodID* id_p) {
  1661   assert(cache != NULL, "sanity check");
  1662   assert(length_p != NULL, "sanity check");
  1663   assert(id_p != NULL, "sanity check");
  1665   // cache size is stored in element[0], other elements offset by one
  1666   *length_p = (size_t)cache[0];
  1667   if (*length_p <= idnum) {  // cache is too short
  1668     *id_p = NULL;
  1669   } else {
  1670     *id_p = cache[idnum+1];  // fetch jmethodID (if any)
  1675 // Lookup a jmethodID, NULL if not found.  Do no blocking, no allocations, no handles
  1676 jmethodID InstanceKlass::jmethod_id_or_null(Method* method) {
  1677   size_t idnum = (size_t)method->method_idnum();
  1678   jmethodID* jmeths = methods_jmethod_ids_acquire();
  1679   size_t length;                                // length assigned as debugging crumb
  1680   jmethodID id = NULL;
  1681   if (jmeths != NULL &&                         // If there is a cache
  1682       (length = (size_t)jmeths[0]) > idnum) {   // and if it is long enough,
  1683     id = jmeths[idnum+1];                       // Look up the id (may be NULL)
  1685   return id;
  1689 // Cache an itable index
  1690 void InstanceKlass::set_cached_itable_index(size_t idnum, int index) {
  1691   int* indices = methods_cached_itable_indices_acquire();
  1692   int* to_dealloc_indices = NULL;
  1694   // We use a double-check locking idiom here because this cache is
  1695   // performance sensitive. In the normal system, this cache only
  1696   // transitions from NULL to non-NULL which is safe because we use
  1697   // release_set_methods_cached_itable_indices() to advertise the
  1698   // new cache. A partially constructed cache should never be seen
  1699   // by a racing thread. Cache reads and writes proceed without a
  1700   // lock, but creation of the cache itself requires no leaks so a
  1701   // lock is generally acquired in that case.
  1702   //
  1703   // If the RedefineClasses() API has been used, then this cache can
  1704   // grow and we'll have transitions from non-NULL to bigger non-NULL.
  1705   // Cache creation requires no leaks and we require safety between all
  1706   // cache accesses and freeing of the old cache so a lock is generally
  1707   // acquired when the RedefineClasses() API has been used.
  1709   if (indices == NULL || idnum_can_increment()) {
  1710     // we need a cache or the cache can grow
  1711     MutexLocker ml(JNICachedItableIndex_lock);
  1712     // reacquire the cache to see if another thread already did the work
  1713     indices = methods_cached_itable_indices_acquire();
  1714     size_t length = 0;
  1715     // cache size is stored in element[0], other elements offset by one
  1716     if (indices == NULL || (length = (size_t)indices[0]) <= idnum) {
  1717       size_t size = MAX2(idnum+1, (size_t)idnum_allocated_count());
  1718       int* new_indices = NEW_C_HEAP_ARRAY(int, size+1, mtClass);
  1719       new_indices[0] = (int)size;
  1720       // copy any existing entries
  1721       size_t i;
  1722       for (i = 0; i < length; i++) {
  1723         new_indices[i+1] = indices[i+1];
  1725       // Set all the rest to -1
  1726       for (i = length; i < size; i++) {
  1727         new_indices[i+1] = -1;
  1729       if (indices != NULL) {
  1730         // We have an old cache to delete so save it for after we
  1731         // drop the lock.
  1732         to_dealloc_indices = indices;
  1734       release_set_methods_cached_itable_indices(indices = new_indices);
  1737     if (idnum_can_increment()) {
  1738       // this cache can grow so we have to write to it safely
  1739       indices[idnum+1] = index;
  1741   } else {
  1742     CHECK_UNHANDLED_OOPS_ONLY(Thread::current()->clear_unhandled_oops());
  1745   if (!idnum_can_increment()) {
  1746     // The cache cannot grow and this JNI itable index value does not
  1747     // have to be unique like a jmethodID. If there is a race to set it,
  1748     // it doesn't matter.
  1749     indices[idnum+1] = index;
  1752   if (to_dealloc_indices != NULL) {
  1753     // we allocated a new cache so free the old one
  1754     FreeHeap(to_dealloc_indices);
  1759 // Retrieve a cached itable index
  1760 int InstanceKlass::cached_itable_index(size_t idnum) {
  1761   int* indices = methods_cached_itable_indices_acquire();
  1762   if (indices != NULL && ((size_t)indices[0]) > idnum) {
  1763      // indices exist and are long enough, retrieve possible cached
  1764     return indices[idnum+1];
  1766   return -1;
  1770 //
  1771 // Walk the list of dependent nmethods searching for nmethods which
  1772 // are dependent on the changes that were passed in and mark them for
  1773 // deoptimization.  Returns the number of nmethods found.
  1774 //
  1775 int InstanceKlass::mark_dependent_nmethods(DepChange& changes) {
  1776   assert_locked_or_safepoint(CodeCache_lock);
  1777   int found = 0;
  1778   nmethodBucket* b = _dependencies;
  1779   while (b != NULL) {
  1780     nmethod* nm = b->get_nmethod();
  1781     // since dependencies aren't removed until an nmethod becomes a zombie,
  1782     // the dependency list may contain nmethods which aren't alive.
  1783     if (nm->is_alive() && !nm->is_marked_for_deoptimization() && nm->check_dependency_on(changes)) {
  1784       if (TraceDependencies) {
  1785         ResourceMark rm;
  1786         tty->print_cr("Marked for deoptimization");
  1787         tty->print_cr("  context = %s", this->external_name());
  1788         changes.print();
  1789         nm->print();
  1790         nm->print_dependencies();
  1792       nm->mark_for_deoptimization();
  1793       found++;
  1795     b = b->next();
  1797   return found;
  1801 //
  1802 // Add an nmethodBucket to the list of dependencies for this nmethod.
  1803 // It's possible that an nmethod has multiple dependencies on this klass
  1804 // so a count is kept for each bucket to guarantee that creation and
  1805 // deletion of dependencies is consistent.
  1806 //
  1807 void InstanceKlass::add_dependent_nmethod(nmethod* nm) {
  1808   assert_locked_or_safepoint(CodeCache_lock);
  1809   nmethodBucket* b = _dependencies;
  1810   nmethodBucket* last = NULL;
  1811   while (b != NULL) {
  1812     if (nm == b->get_nmethod()) {
  1813       b->increment();
  1814       return;
  1816     b = b->next();
  1818   _dependencies = new nmethodBucket(nm, _dependencies);
  1822 //
  1823 // Decrement count of the nmethod in the dependency list and remove
  1824 // the bucket competely when the count goes to 0.  This method must
  1825 // find a corresponding bucket otherwise there's a bug in the
  1826 // recording of dependecies.
  1827 //
  1828 void InstanceKlass::remove_dependent_nmethod(nmethod* nm) {
  1829   assert_locked_or_safepoint(CodeCache_lock);
  1830   nmethodBucket* b = _dependencies;
  1831   nmethodBucket* last = NULL;
  1832   while (b != NULL) {
  1833     if (nm == b->get_nmethod()) {
  1834       if (b->decrement() == 0) {
  1835         if (last == NULL) {
  1836           _dependencies = b->next();
  1837         } else {
  1838           last->set_next(b->next());
  1840         delete b;
  1842       return;
  1844     last = b;
  1845     b = b->next();
  1847 #ifdef ASSERT
  1848   tty->print_cr("### %s can't find dependent nmethod:", this->external_name());
  1849   nm->print();
  1850 #endif // ASSERT
  1851   ShouldNotReachHere();
  1855 #ifndef PRODUCT
  1856 void InstanceKlass::print_dependent_nmethods(bool verbose) {
  1857   nmethodBucket* b = _dependencies;
  1858   int idx = 0;
  1859   while (b != NULL) {
  1860     nmethod* nm = b->get_nmethod();
  1861     tty->print("[%d] count=%d { ", idx++, b->count());
  1862     if (!verbose) {
  1863       nm->print_on(tty, "nmethod");
  1864       tty->print_cr(" } ");
  1865     } else {
  1866       nm->print();
  1867       nm->print_dependencies();
  1868       tty->print_cr("--- } ");
  1870     b = b->next();
  1875 bool InstanceKlass::is_dependent_nmethod(nmethod* nm) {
  1876   nmethodBucket* b = _dependencies;
  1877   while (b != NULL) {
  1878     if (nm == b->get_nmethod()) {
  1879       return true;
  1881     b = b->next();
  1883   return false;
  1885 #endif //PRODUCT
  1888 // Garbage collection
  1890 #ifdef ASSERT
  1891 template <class T> void assert_is_in(T *p) {
  1892   T heap_oop = oopDesc::load_heap_oop(p);
  1893   if (!oopDesc::is_null(heap_oop)) {
  1894     oop o = oopDesc::decode_heap_oop_not_null(heap_oop);
  1895     assert(Universe::heap()->is_in(o), "should be in heap");
  1898 template <class T> void assert_is_in_closed_subset(T *p) {
  1899   T heap_oop = oopDesc::load_heap_oop(p);
  1900   if (!oopDesc::is_null(heap_oop)) {
  1901     oop o = oopDesc::decode_heap_oop_not_null(heap_oop);
  1902     assert(Universe::heap()->is_in_closed_subset(o),
  1903            err_msg("should be in closed *p " INTPTR_FORMAT " " INTPTR_FORMAT, (address)p, (address)o));
  1906 template <class T> void assert_is_in_reserved(T *p) {
  1907   T heap_oop = oopDesc::load_heap_oop(p);
  1908   if (!oopDesc::is_null(heap_oop)) {
  1909     oop o = oopDesc::decode_heap_oop_not_null(heap_oop);
  1910     assert(Universe::heap()->is_in_reserved(o), "should be in reserved");
  1913 template <class T> void assert_nothing(T *p) {}
  1915 #else
  1916 template <class T> void assert_is_in(T *p) {}
  1917 template <class T> void assert_is_in_closed_subset(T *p) {}
  1918 template <class T> void assert_is_in_reserved(T *p) {}
  1919 template <class T> void assert_nothing(T *p) {}
  1920 #endif // ASSERT
  1922 //
  1923 // Macros that iterate over areas of oops which are specialized on type of
  1924 // oop pointer either narrow or wide, depending on UseCompressedOops
  1925 //
  1926 // Parameters are:
  1927 //   T         - type of oop to point to (either oop or narrowOop)
  1928 //   start_p   - starting pointer for region to iterate over
  1929 //   count     - number of oops or narrowOops to iterate over
  1930 //   do_oop    - action to perform on each oop (it's arbitrary C code which
  1931 //               makes it more efficient to put in a macro rather than making
  1932 //               it a template function)
  1933 //   assert_fn - assert function which is template function because performance
  1934 //               doesn't matter when enabled.
  1935 #define InstanceKlass_SPECIALIZED_OOP_ITERATE( \
  1936   T, start_p, count, do_oop,                \
  1937   assert_fn)                                \
  1938 {                                           \
  1939   T* p         = (T*)(start_p);             \
  1940   T* const end = p + (count);               \
  1941   while (p < end) {                         \
  1942     (assert_fn)(p);                         \
  1943     do_oop;                                 \
  1944     ++p;                                    \
  1945   }                                         \
  1948 #define InstanceKlass_SPECIALIZED_OOP_REVERSE_ITERATE( \
  1949   T, start_p, count, do_oop,                \
  1950   assert_fn)                                \
  1951 {                                           \
  1952   T* const start = (T*)(start_p);           \
  1953   T*       p     = start + (count);         \
  1954   while (start < p) {                       \
  1955     --p;                                    \
  1956     (assert_fn)(p);                         \
  1957     do_oop;                                 \
  1958   }                                         \
  1961 #define InstanceKlass_SPECIALIZED_BOUNDED_OOP_ITERATE( \
  1962   T, start_p, count, low, high,             \
  1963   do_oop, assert_fn)                        \
  1964 {                                           \
  1965   T* const l = (T*)(low);                   \
  1966   T* const h = (T*)(high);                  \
  1967   assert(mask_bits((intptr_t)l, sizeof(T)-1) == 0 && \
  1968          mask_bits((intptr_t)h, sizeof(T)-1) == 0,   \
  1969          "bounded region must be properly aligned"); \
  1970   T* p       = (T*)(start_p);               \
  1971   T* end     = p + (count);                 \
  1972   if (p < l) p = l;                         \
  1973   if (end > h) end = h;                     \
  1974   while (p < end) {                         \
  1975     (assert_fn)(p);                         \
  1976     do_oop;                                 \
  1977     ++p;                                    \
  1978   }                                         \
  1982 // The following macros call specialized macros, passing either oop or
  1983 // narrowOop as the specialization type.  These test the UseCompressedOops
  1984 // flag.
  1985 #define InstanceKlass_OOP_MAP_ITERATE(obj, do_oop, assert_fn)            \
  1986 {                                                                        \
  1987   /* Compute oopmap block range. The common case                         \
  1988      is nonstatic_oop_map_size == 1. */                                  \
  1989   OopMapBlock* map           = start_of_nonstatic_oop_maps();            \
  1990   OopMapBlock* const end_map = map + nonstatic_oop_map_count();          \
  1991   if (UseCompressedOops) {                                               \
  1992     while (map < end_map) {                                              \
  1993       InstanceKlass_SPECIALIZED_OOP_ITERATE(narrowOop,                   \
  1994         obj->obj_field_addr<narrowOop>(map->offset()), map->count(),     \
  1995         do_oop, assert_fn)                                               \
  1996       ++map;                                                             \
  1997     }                                                                    \
  1998   } else {                                                               \
  1999     while (map < end_map) {                                              \
  2000       InstanceKlass_SPECIALIZED_OOP_ITERATE(oop,                         \
  2001         obj->obj_field_addr<oop>(map->offset()), map->count(),           \
  2002         do_oop, assert_fn)                                               \
  2003       ++map;                                                             \
  2004     }                                                                    \
  2005   }                                                                      \
  2008 #define InstanceKlass_OOP_MAP_REVERSE_ITERATE(obj, do_oop, assert_fn)    \
  2009 {                                                                        \
  2010   OopMapBlock* const start_map = start_of_nonstatic_oop_maps();          \
  2011   OopMapBlock* map             = start_map + nonstatic_oop_map_count();  \
  2012   if (UseCompressedOops) {                                               \
  2013     while (start_map < map) {                                            \
  2014       --map;                                                             \
  2015       InstanceKlass_SPECIALIZED_OOP_REVERSE_ITERATE(narrowOop,           \
  2016         obj->obj_field_addr<narrowOop>(map->offset()), map->count(),     \
  2017         do_oop, assert_fn)                                               \
  2018     }                                                                    \
  2019   } else {                                                               \
  2020     while (start_map < map) {                                            \
  2021       --map;                                                             \
  2022       InstanceKlass_SPECIALIZED_OOP_REVERSE_ITERATE(oop,                 \
  2023         obj->obj_field_addr<oop>(map->offset()), map->count(),           \
  2024         do_oop, assert_fn)                                               \
  2025     }                                                                    \
  2026   }                                                                      \
  2029 #define InstanceKlass_BOUNDED_OOP_MAP_ITERATE(obj, low, high, do_oop,    \
  2030                                               assert_fn)                 \
  2031 {                                                                        \
  2032   /* Compute oopmap block range. The common case is                      \
  2033      nonstatic_oop_map_size == 1, so we accept the                       \
  2034      usually non-existent extra overhead of examining                    \
  2035      all the maps. */                                                    \
  2036   OopMapBlock* map           = start_of_nonstatic_oop_maps();            \
  2037   OopMapBlock* const end_map = map + nonstatic_oop_map_count();          \
  2038   if (UseCompressedOops) {                                               \
  2039     while (map < end_map) {                                              \
  2040       InstanceKlass_SPECIALIZED_BOUNDED_OOP_ITERATE(narrowOop,           \
  2041         obj->obj_field_addr<narrowOop>(map->offset()), map->count(),     \
  2042         low, high,                                                       \
  2043         do_oop, assert_fn)                                               \
  2044       ++map;                                                             \
  2045     }                                                                    \
  2046   } else {                                                               \
  2047     while (map < end_map) {                                              \
  2048       InstanceKlass_SPECIALIZED_BOUNDED_OOP_ITERATE(oop,                 \
  2049         obj->obj_field_addr<oop>(map->offset()), map->count(),           \
  2050         low, high,                                                       \
  2051         do_oop, assert_fn)                                               \
  2052       ++map;                                                             \
  2053     }                                                                    \
  2054   }                                                                      \
  2057 void InstanceKlass::oop_follow_contents(oop obj) {
  2058   assert(obj != NULL, "can't follow the content of NULL object");
  2059   MarkSweep::follow_klass(obj->klass());
  2060   InstanceKlass_OOP_MAP_ITERATE( \
  2061     obj, \
  2062     MarkSweep::mark_and_push(p), \
  2063     assert_is_in_closed_subset)
  2066 #if INCLUDE_ALL_GCS
  2067 void InstanceKlass::oop_follow_contents(ParCompactionManager* cm,
  2068                                         oop obj) {
  2069   assert(obj != NULL, "can't follow the content of NULL object");
  2070   PSParallelCompact::follow_klass(cm, obj->klass());
  2071   // Only mark the header and let the scan of the meta-data mark
  2072   // everything else.
  2073   InstanceKlass_OOP_MAP_ITERATE( \
  2074     obj, \
  2075     PSParallelCompact::mark_and_push(cm, p), \
  2076     assert_is_in)
  2078 #endif // INCLUDE_ALL_GCS
  2080 // closure's do_metadata() method dictates whether the given closure should be
  2081 // applied to the klass ptr in the object header.
  2083 #define if_do_metadata_checked(closure, nv_suffix)                    \
  2084   /* Make sure the non-virtual and the virtual versions match. */     \
  2085   assert(closure->do_metadata##nv_suffix() == closure->do_metadata(), \
  2086       "Inconsistency in do_metadata");                                \
  2087   if (closure->do_metadata##nv_suffix())
  2089 #define InstanceKlass_OOP_OOP_ITERATE_DEFN(OopClosureType, nv_suffix)        \
  2091 int InstanceKlass::oop_oop_iterate##nv_suffix(oop obj, OopClosureType* closure) { \
  2092   SpecializationStats::record_iterate_call##nv_suffix(SpecializationStats::ik);\
  2093   /* header */                                                          \
  2094   if_do_metadata_checked(closure, nv_suffix) {                          \
  2095     closure->do_klass##nv_suffix(obj->klass());                         \
  2096   }                                                                     \
  2097   InstanceKlass_OOP_MAP_ITERATE(                                        \
  2098     obj,                                                                \
  2099     SpecializationStats::                                               \
  2100       record_do_oop_call##nv_suffix(SpecializationStats::ik);           \
  2101     (closure)->do_oop##nv_suffix(p),                                    \
  2102     assert_is_in_closed_subset)                                         \
  2103   return size_helper();                                                 \
  2106 #if INCLUDE_ALL_GCS
  2107 #define InstanceKlass_OOP_OOP_ITERATE_BACKWARDS_DEFN(OopClosureType, nv_suffix) \
  2109 int InstanceKlass::oop_oop_iterate_backwards##nv_suffix(oop obj,                \
  2110                                               OopClosureType* closure) {        \
  2111   SpecializationStats::record_iterate_call##nv_suffix(SpecializationStats::ik); \
  2112   /* header */                                                                  \
  2113   if_do_metadata_checked(closure, nv_suffix) {                                  \
  2114     closure->do_klass##nv_suffix(obj->klass());                                 \
  2115   }                                                                             \
  2116   /* instance variables */                                                      \
  2117   InstanceKlass_OOP_MAP_REVERSE_ITERATE(                                        \
  2118     obj,                                                                        \
  2119     SpecializationStats::record_do_oop_call##nv_suffix(SpecializationStats::ik);\
  2120     (closure)->do_oop##nv_suffix(p),                                            \
  2121     assert_is_in_closed_subset)                                                 \
  2122    return size_helper();                                                        \
  2124 #endif // INCLUDE_ALL_GCS
  2126 #define InstanceKlass_OOP_OOP_ITERATE_DEFN_m(OopClosureType, nv_suffix) \
  2128 int InstanceKlass::oop_oop_iterate##nv_suffix##_m(oop obj,              \
  2129                                                   OopClosureType* closure, \
  2130                                                   MemRegion mr) {          \
  2131   SpecializationStats::record_iterate_call##nv_suffix(SpecializationStats::ik);\
  2132   if_do_metadata_checked(closure, nv_suffix) {                           \
  2133     if (mr.contains(obj)) {                                              \
  2134       closure->do_klass##nv_suffix(obj->klass());                        \
  2135     }                                                                    \
  2136   }                                                                      \
  2137   InstanceKlass_BOUNDED_OOP_MAP_ITERATE(                                 \
  2138     obj, mr.start(), mr.end(),                                           \
  2139     (closure)->do_oop##nv_suffix(p),                                     \
  2140     assert_is_in_closed_subset)                                          \
  2141   return size_helper();                                                  \
  2144 ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceKlass_OOP_OOP_ITERATE_DEFN)
  2145 ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceKlass_OOP_OOP_ITERATE_DEFN)
  2146 ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceKlass_OOP_OOP_ITERATE_DEFN_m)
  2147 ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceKlass_OOP_OOP_ITERATE_DEFN_m)
  2148 #if INCLUDE_ALL_GCS
  2149 ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceKlass_OOP_OOP_ITERATE_BACKWARDS_DEFN)
  2150 ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceKlass_OOP_OOP_ITERATE_BACKWARDS_DEFN)
  2151 #endif // INCLUDE_ALL_GCS
  2153 int InstanceKlass::oop_adjust_pointers(oop obj) {
  2154   int size = size_helper();
  2155   InstanceKlass_OOP_MAP_ITERATE( \
  2156     obj, \
  2157     MarkSweep::adjust_pointer(p), \
  2158     assert_is_in)
  2159   MarkSweep::adjust_klass(obj->klass());
  2160   return size;
  2163 #if INCLUDE_ALL_GCS
  2164 void InstanceKlass::oop_push_contents(PSPromotionManager* pm, oop obj) {
  2165   InstanceKlass_OOP_MAP_REVERSE_ITERATE( \
  2166     obj, \
  2167     if (PSScavenge::should_scavenge(p)) { \
  2168       pm->claim_or_forward_depth(p); \
  2169     }, \
  2170     assert_nothing )
  2173 int InstanceKlass::oop_update_pointers(ParCompactionManager* cm, oop obj) {
  2174   int size = size_helper();
  2175   InstanceKlass_OOP_MAP_ITERATE( \
  2176     obj, \
  2177     PSParallelCompact::adjust_pointer(p), \
  2178     assert_is_in)
  2179   obj->update_header(cm);
  2180   return size;
  2183 #endif // INCLUDE_ALL_GCS
  2185 void InstanceKlass::clean_implementors_list(BoolObjectClosure* is_alive) {
  2186   assert(is_loader_alive(is_alive), "this klass should be live");
  2187   if (is_interface()) {
  2188     if (ClassUnloading) {
  2189       Klass* impl = implementor();
  2190       if (impl != NULL) {
  2191         if (!impl->is_loader_alive(is_alive)) {
  2192           // remove this guy
  2193           Klass** klass = adr_implementor();
  2194           assert(klass != NULL, "null klass");
  2195           if (klass != NULL) {
  2196             *klass = NULL;
  2204 void InstanceKlass::clean_method_data(BoolObjectClosure* is_alive) {
  2205   for (int m = 0; m < methods()->length(); m++) {
  2206     MethodData* mdo = methods()->at(m)->method_data();
  2207     if (mdo != NULL) {
  2208       for (ProfileData* data = mdo->first_data();
  2209            mdo->is_valid(data);
  2210            data = mdo->next_data(data)) {
  2211         data->clean_weak_klass_links(is_alive);
  2218 static void remove_unshareable_in_class(Klass* k) {
  2219   // remove klass's unshareable info
  2220   k->remove_unshareable_info();
  2223 void InstanceKlass::remove_unshareable_info() {
  2224   Klass::remove_unshareable_info();
  2225   // Unlink the class
  2226   if (is_linked()) {
  2227     unlink_class();
  2229   init_implementor();
  2231   constants()->remove_unshareable_info();
  2233   for (int i = 0; i < methods()->length(); i++) {
  2234     Method* m = methods()->at(i);
  2235     m->remove_unshareable_info();
  2238   // do array classes also.
  2239   array_klasses_do(remove_unshareable_in_class);
  2242 void restore_unshareable_in_class(Klass* k, TRAPS) {
  2243   k->restore_unshareable_info(CHECK);
  2246 void InstanceKlass::restore_unshareable_info(TRAPS) {
  2247   Klass::restore_unshareable_info(CHECK);
  2248   instanceKlassHandle ik(THREAD, this);
  2250   Array<Method*>* methods = ik->methods();
  2251   int num_methods = methods->length();
  2252   for (int index2 = 0; index2 < num_methods; ++index2) {
  2253     methodHandle m(THREAD, methods->at(index2));
  2254     m()->link_method(m, CHECK);
  2255     // restore method's vtable by calling a virtual function
  2256     m->restore_vtable();
  2258   if (JvmtiExport::has_redefined_a_class()) {
  2259     // Reinitialize vtable because RedefineClasses may have changed some
  2260     // entries in this vtable for super classes so the CDS vtable might
  2261     // point to old or obsolete entries.  RedefineClasses doesn't fix up
  2262     // vtables in the shared system dictionary, only the main one.
  2263     // It also redefines the itable too so fix that too.
  2264     ResourceMark rm(THREAD);
  2265     ik->vtable()->initialize_vtable(false, CHECK);
  2266     ik->itable()->initialize_itable(false, CHECK);
  2269   // restore constant pool resolved references
  2270   ik->constants()->restore_unshareable_info(CHECK);
  2272   ik->array_klasses_do(restore_unshareable_in_class, CHECK);
  2275 static void clear_all_breakpoints(Method* m) {
  2276   m->clear_all_breakpoints();
  2280 void InstanceKlass::notify_unload_class(InstanceKlass* ik) {
  2281   // notify the debugger
  2282   if (JvmtiExport::should_post_class_unload()) {
  2283     JvmtiExport::post_class_unload(ik);
  2286   // notify ClassLoadingService of class unload
  2287   ClassLoadingService::notify_class_unloaded(ik);
  2290 void InstanceKlass::release_C_heap_structures(InstanceKlass* ik) {
  2291   // Clean up C heap
  2292   ik->release_C_heap_structures();
  2293   ik->constants()->release_C_heap_structures();
  2296 void InstanceKlass::release_C_heap_structures() {
  2298   // Can't release the constant pool here because the constant pool can be
  2299   // deallocated separately from the InstanceKlass for default methods and
  2300   // redefine classes.
  2302   // Deallocate oop map cache
  2303   if (_oop_map_cache != NULL) {
  2304     delete _oop_map_cache;
  2305     _oop_map_cache = NULL;
  2308   // Deallocate JNI identifiers for jfieldIDs
  2309   JNIid::deallocate(jni_ids());
  2310   set_jni_ids(NULL);
  2312   jmethodID* jmeths = methods_jmethod_ids_acquire();
  2313   if (jmeths != (jmethodID*)NULL) {
  2314     release_set_methods_jmethod_ids(NULL);
  2315     FreeHeap(jmeths);
  2318   // Deallocate MemberNameTable
  2320     Mutex* lock_or_null = SafepointSynchronize::is_at_safepoint() ? NULL : MemberNameTable_lock;
  2321     MutexLockerEx ml(lock_or_null, Mutex::_no_safepoint_check_flag);
  2322     MemberNameTable* mnt = member_names();
  2323     if (mnt != NULL) {
  2324       delete mnt;
  2325       set_member_names(NULL);
  2329   int* indices = methods_cached_itable_indices_acquire();
  2330   if (indices != (int*)NULL) {
  2331     release_set_methods_cached_itable_indices(NULL);
  2332     FreeHeap(indices);
  2335   // release dependencies
  2336   nmethodBucket* b = _dependencies;
  2337   _dependencies = NULL;
  2338   while (b != NULL) {
  2339     nmethodBucket* next = b->next();
  2340     delete b;
  2341     b = next;
  2344   // Deallocate breakpoint records
  2345   if (breakpoints() != 0x0) {
  2346     methods_do(clear_all_breakpoints);
  2347     assert(breakpoints() == 0x0, "should have cleared breakpoints");
  2350   // deallocate information about previous versions
  2351   if (_previous_versions != NULL) {
  2352     for (int i = _previous_versions->length() - 1; i >= 0; i--) {
  2353       PreviousVersionNode * pv_node = _previous_versions->at(i);
  2354       delete pv_node;
  2356     delete _previous_versions;
  2357     _previous_versions = NULL;
  2360   // deallocate the cached class file
  2361   if (_cached_class_file != NULL) {
  2362     os::free(_cached_class_file, mtClass);
  2363     _cached_class_file = NULL;
  2366   // Decrement symbol reference counts associated with the unloaded class.
  2367   if (_name != NULL) _name->decrement_refcount();
  2368   // unreference array name derived from this class name (arrays of an unloaded
  2369   // class can't be referenced anymore).
  2370   if (_array_name != NULL)  _array_name->decrement_refcount();
  2371   if (_source_debug_extension != NULL) FREE_C_HEAP_ARRAY(char, _source_debug_extension, mtClass);
  2373   assert(_total_instanceKlass_count >= 1, "Sanity check");
  2374   Atomic::dec(&_total_instanceKlass_count);
  2377 void InstanceKlass::set_source_debug_extension(char* array, int length) {
  2378   if (array == NULL) {
  2379     _source_debug_extension = NULL;
  2380   } else {
  2381     // Adding one to the attribute length in order to store a null terminator
  2382     // character could cause an overflow because the attribute length is
  2383     // already coded with an u4 in the classfile, but in practice, it's
  2384     // unlikely to happen.
  2385     assert((length+1) > length, "Overflow checking");
  2386     char* sde = NEW_C_HEAP_ARRAY(char, (length + 1), mtClass);
  2387     for (int i = 0; i < length; i++) {
  2388       sde[i] = array[i];
  2390     sde[length] = '\0';
  2391     _source_debug_extension = sde;
  2395 address InstanceKlass::static_field_addr(int offset) {
  2396   return (address)(offset + InstanceMirrorKlass::offset_of_static_fields() + (intptr_t)java_mirror());
  2400 const char* InstanceKlass::signature_name() const {
  2401   const char* src = (const char*) (name()->as_C_string());
  2402   const int src_length = (int)strlen(src);
  2403   char* dest = NEW_RESOURCE_ARRAY(char, src_length + 3);
  2404   int src_index = 0;
  2405   int dest_index = 0;
  2406   dest[dest_index++] = 'L';
  2407   while (src_index < src_length) {
  2408     dest[dest_index++] = src[src_index++];
  2410   dest[dest_index++] = ';';
  2411   dest[dest_index] = '\0';
  2412   return dest;
  2415 // different verisons of is_same_class_package
  2416 bool InstanceKlass::is_same_class_package(Klass* class2) {
  2417   Klass* class1 = this;
  2418   oop classloader1 = InstanceKlass::cast(class1)->class_loader();
  2419   Symbol* classname1 = class1->name();
  2421   if (class2->oop_is_objArray()) {
  2422     class2 = ObjArrayKlass::cast(class2)->bottom_klass();
  2424   oop classloader2;
  2425   if (class2->oop_is_instance()) {
  2426     classloader2 = InstanceKlass::cast(class2)->class_loader();
  2427   } else {
  2428     assert(class2->oop_is_typeArray(), "should be type array");
  2429     classloader2 = NULL;
  2431   Symbol* classname2 = class2->name();
  2433   return InstanceKlass::is_same_class_package(classloader1, classname1,
  2434                                               classloader2, classname2);
  2437 bool InstanceKlass::is_same_class_package(oop classloader2, Symbol* classname2) {
  2438   Klass* class1 = this;
  2439   oop classloader1 = InstanceKlass::cast(class1)->class_loader();
  2440   Symbol* classname1 = class1->name();
  2442   return InstanceKlass::is_same_class_package(classloader1, classname1,
  2443                                               classloader2, classname2);
  2446 // return true if two classes are in the same package, classloader
  2447 // and classname information is enough to determine a class's package
  2448 bool InstanceKlass::is_same_class_package(oop class_loader1, Symbol* class_name1,
  2449                                           oop class_loader2, Symbol* class_name2) {
  2450   if (class_loader1 != class_loader2) {
  2451     return false;
  2452   } else if (class_name1 == class_name2) {
  2453     return true;                // skip painful bytewise comparison
  2454   } else {
  2455     ResourceMark rm;
  2457     // The Symbol*'s are in UTF8 encoding. Since we only need to check explicitly
  2458     // for ASCII characters ('/', 'L', '['), we can keep them in UTF8 encoding.
  2459     // Otherwise, we just compare jbyte values between the strings.
  2460     const jbyte *name1 = class_name1->base();
  2461     const jbyte *name2 = class_name2->base();
  2463     const jbyte *last_slash1 = UTF8::strrchr(name1, class_name1->utf8_length(), '/');
  2464     const jbyte *last_slash2 = UTF8::strrchr(name2, class_name2->utf8_length(), '/');
  2466     if ((last_slash1 == NULL) || (last_slash2 == NULL)) {
  2467       // One of the two doesn't have a package.  Only return true
  2468       // if the other one also doesn't have a package.
  2469       return last_slash1 == last_slash2;
  2470     } else {
  2471       // Skip over '['s
  2472       if (*name1 == '[') {
  2473         do {
  2474           name1++;
  2475         } while (*name1 == '[');
  2476         if (*name1 != 'L') {
  2477           // Something is terribly wrong.  Shouldn't be here.
  2478           return false;
  2481       if (*name2 == '[') {
  2482         do {
  2483           name2++;
  2484         } while (*name2 == '[');
  2485         if (*name2 != 'L') {
  2486           // Something is terribly wrong.  Shouldn't be here.
  2487           return false;
  2491       // Check that package part is identical
  2492       int length1 = last_slash1 - name1;
  2493       int length2 = last_slash2 - name2;
  2495       return UTF8::equal(name1, length1, name2, length2);
  2500 // Returns true iff super_method can be overridden by a method in targetclassname
  2501 // See JSL 3rd edition 8.4.6.1
  2502 // Assumes name-signature match
  2503 // "this" is InstanceKlass of super_method which must exist
  2504 // note that the InstanceKlass of the method in the targetclassname has not always been created yet
  2505 bool InstanceKlass::is_override(methodHandle super_method, Handle targetclassloader, Symbol* targetclassname, TRAPS) {
  2506    // Private methods can not be overridden
  2507    if (super_method->is_private()) {
  2508      return false;
  2510    // If super method is accessible, then override
  2511    if ((super_method->is_protected()) ||
  2512        (super_method->is_public())) {
  2513      return true;
  2515    // Package-private methods are not inherited outside of package
  2516    assert(super_method->is_package_private(), "must be package private");
  2517    return(is_same_class_package(targetclassloader(), targetclassname));
  2520 /* defined for now in jvm.cpp, for historical reasons *--
  2521 Klass* InstanceKlass::compute_enclosing_class_impl(instanceKlassHandle self,
  2522                                                      Symbol*& simple_name_result, TRAPS) {
  2523   ...
  2525 */
  2527 // tell if two classes have the same enclosing class (at package level)
  2528 bool InstanceKlass::is_same_package_member_impl(instanceKlassHandle class1,
  2529                                                 Klass* class2_oop, TRAPS) {
  2530   if (class2_oop == class1())                       return true;
  2531   if (!class2_oop->oop_is_instance())  return false;
  2532   instanceKlassHandle class2(THREAD, class2_oop);
  2534   // must be in same package before we try anything else
  2535   if (!class1->is_same_class_package(class2->class_loader(), class2->name()))
  2536     return false;
  2538   // As long as there is an outer1.getEnclosingClass,
  2539   // shift the search outward.
  2540   instanceKlassHandle outer1 = class1;
  2541   for (;;) {
  2542     // As we walk along, look for equalities between outer1 and class2.
  2543     // Eventually, the walks will terminate as outer1 stops
  2544     // at the top-level class around the original class.
  2545     bool ignore_inner_is_member;
  2546     Klass* next = outer1->compute_enclosing_class(&ignore_inner_is_member,
  2547                                                     CHECK_false);
  2548     if (next == NULL)  break;
  2549     if (next == class2())  return true;
  2550     outer1 = instanceKlassHandle(THREAD, next);
  2553   // Now do the same for class2.
  2554   instanceKlassHandle outer2 = class2;
  2555   for (;;) {
  2556     bool ignore_inner_is_member;
  2557     Klass* next = outer2->compute_enclosing_class(&ignore_inner_is_member,
  2558                                                     CHECK_false);
  2559     if (next == NULL)  break;
  2560     // Might as well check the new outer against all available values.
  2561     if (next == class1())  return true;
  2562     if (next == outer1())  return true;
  2563     outer2 = instanceKlassHandle(THREAD, next);
  2566   // If by this point we have not found an equality between the
  2567   // two classes, we know they are in separate package members.
  2568   return false;
  2572 jint InstanceKlass::compute_modifier_flags(TRAPS) const {
  2573   jint access = access_flags().as_int();
  2575   // But check if it happens to be member class.
  2576   instanceKlassHandle ik(THREAD, this);
  2577   InnerClassesIterator iter(ik);
  2578   for (; !iter.done(); iter.next()) {
  2579     int ioff = iter.inner_class_info_index();
  2580     // Inner class attribute can be zero, skip it.
  2581     // Strange but true:  JVM spec. allows null inner class refs.
  2582     if (ioff == 0) continue;
  2584     // only look at classes that are already loaded
  2585     // since we are looking for the flags for our self.
  2586     Symbol* inner_name = ik->constants()->klass_name_at(ioff);
  2587     if ((ik->name() == inner_name)) {
  2588       // This is really a member class.
  2589       access = iter.inner_access_flags();
  2590       break;
  2593   // Remember to strip ACC_SUPER bit
  2594   return (access & (~JVM_ACC_SUPER)) & JVM_ACC_WRITTEN_FLAGS;
  2597 jint InstanceKlass::jvmti_class_status() const {
  2598   jint result = 0;
  2600   if (is_linked()) {
  2601     result |= JVMTI_CLASS_STATUS_VERIFIED | JVMTI_CLASS_STATUS_PREPARED;
  2604   if (is_initialized()) {
  2605     assert(is_linked(), "Class status is not consistent");
  2606     result |= JVMTI_CLASS_STATUS_INITIALIZED;
  2608   if (is_in_error_state()) {
  2609     result |= JVMTI_CLASS_STATUS_ERROR;
  2611   return result;
  2614 Method* InstanceKlass::method_at_itable(Klass* holder, int index, TRAPS) {
  2615   itableOffsetEntry* ioe = (itableOffsetEntry*)start_of_itable();
  2616   int method_table_offset_in_words = ioe->offset()/wordSize;
  2617   int nof_interfaces = (method_table_offset_in_words - itable_offset_in_words())
  2618                        / itableOffsetEntry::size();
  2620   for (int cnt = 0 ; ; cnt ++, ioe ++) {
  2621     // If the interface isn't implemented by the receiver class,
  2622     // the VM should throw IncompatibleClassChangeError.
  2623     if (cnt >= nof_interfaces) {
  2624       THROW_NULL(vmSymbols::java_lang_IncompatibleClassChangeError());
  2627     Klass* ik = ioe->interface_klass();
  2628     if (ik == holder) break;
  2631   itableMethodEntry* ime = ioe->first_method_entry(this);
  2632   Method* m = ime[index].method();
  2633   if (m == NULL) {
  2634     THROW_NULL(vmSymbols::java_lang_AbstractMethodError());
  2636   return m;
  2639 // On-stack replacement stuff
  2640 void InstanceKlass::add_osr_nmethod(nmethod* n) {
  2641   // only one compilation can be active
  2642   NEEDS_CLEANUP
  2643   // This is a short non-blocking critical region, so the no safepoint check is ok.
  2644   OsrList_lock->lock_without_safepoint_check();
  2645   assert(n->is_osr_method(), "wrong kind of nmethod");
  2646   n->set_osr_link(osr_nmethods_head());
  2647   set_osr_nmethods_head(n);
  2648   // Raise the highest osr level if necessary
  2649   if (TieredCompilation) {
  2650     Method* m = n->method();
  2651     m->set_highest_osr_comp_level(MAX2(m->highest_osr_comp_level(), n->comp_level()));
  2653   // Remember to unlock again
  2654   OsrList_lock->unlock();
  2656   // Get rid of the osr methods for the same bci that have lower levels.
  2657   if (TieredCompilation) {
  2658     for (int l = CompLevel_limited_profile; l < n->comp_level(); l++) {
  2659       nmethod *inv = lookup_osr_nmethod(n->method(), n->osr_entry_bci(), l, true);
  2660       if (inv != NULL && inv->is_in_use()) {
  2661         inv->make_not_entrant();
  2668 void InstanceKlass::remove_osr_nmethod(nmethod* n) {
  2669   // This is a short non-blocking critical region, so the no safepoint check is ok.
  2670   OsrList_lock->lock_without_safepoint_check();
  2671   assert(n->is_osr_method(), "wrong kind of nmethod");
  2672   nmethod* last = NULL;
  2673   nmethod* cur  = osr_nmethods_head();
  2674   int max_level = CompLevel_none;  // Find the max comp level excluding n
  2675   Method* m = n->method();
  2676   // Search for match
  2677   while(cur != NULL && cur != n) {
  2678     if (TieredCompilation) {
  2679       // Find max level before n
  2680       max_level = MAX2(max_level, cur->comp_level());
  2682     last = cur;
  2683     cur = cur->osr_link();
  2685   nmethod* next = NULL;
  2686   if (cur == n) {
  2687     next = cur->osr_link();
  2688     if (last == NULL) {
  2689       // Remove first element
  2690       set_osr_nmethods_head(next);
  2691     } else {
  2692       last->set_osr_link(next);
  2695   n->set_osr_link(NULL);
  2696   if (TieredCompilation) {
  2697     cur = next;
  2698     while (cur != NULL) {
  2699       // Find max level after n
  2700       max_level = MAX2(max_level, cur->comp_level());
  2701       cur = cur->osr_link();
  2703     m->set_highest_osr_comp_level(max_level);
  2705   // Remember to unlock again
  2706   OsrList_lock->unlock();
  2709 nmethod* InstanceKlass::lookup_osr_nmethod(const Method* m, int bci, int comp_level, bool match_level) const {
  2710   // This is a short non-blocking critical region, so the no safepoint check is ok.
  2711   OsrList_lock->lock_without_safepoint_check();
  2712   nmethod* osr = osr_nmethods_head();
  2713   nmethod* best = NULL;
  2714   while (osr != NULL) {
  2715     assert(osr->is_osr_method(), "wrong kind of nmethod found in chain");
  2716     // There can be a time when a c1 osr method exists but we are waiting
  2717     // for a c2 version. When c2 completes its osr nmethod we will trash
  2718     // the c1 version and only be able to find the c2 version. However
  2719     // while we overflow in the c1 code at back branches we don't want to
  2720     // try and switch to the same code as we are already running
  2722     if (osr->method() == m &&
  2723         (bci == InvocationEntryBci || osr->osr_entry_bci() == bci)) {
  2724       if (match_level) {
  2725         if (osr->comp_level() == comp_level) {
  2726           // Found a match - return it.
  2727           OsrList_lock->unlock();
  2728           return osr;
  2730       } else {
  2731         if (best == NULL || (osr->comp_level() > best->comp_level())) {
  2732           if (osr->comp_level() == CompLevel_highest_tier) {
  2733             // Found the best possible - return it.
  2734             OsrList_lock->unlock();
  2735             return osr;
  2737           best = osr;
  2741     osr = osr->osr_link();
  2743   OsrList_lock->unlock();
  2744   if (best != NULL && best->comp_level() >= comp_level && match_level == false) {
  2745     return best;
  2747   return NULL;
  2750 void InstanceKlass::add_member_name(int index, Handle mem_name) {
  2751   jweak mem_name_wref = JNIHandles::make_weak_global(mem_name);
  2752   MutexLocker ml(MemberNameTable_lock);
  2753   assert(0 <= index && index < idnum_allocated_count(), "index is out of bounds");
  2754   DEBUG_ONLY(No_Safepoint_Verifier nsv);
  2756   if (_member_names == NULL) {
  2757     _member_names = new (ResourceObj::C_HEAP, mtClass) MemberNameTable(idnum_allocated_count());
  2759   _member_names->add_member_name(index, mem_name_wref);
  2762 oop InstanceKlass::get_member_name(int index) {
  2763   MutexLocker ml(MemberNameTable_lock);
  2764   assert(0 <= index && index < idnum_allocated_count(), "index is out of bounds");
  2765   DEBUG_ONLY(No_Safepoint_Verifier nsv);
  2767   if (_member_names == NULL) {
  2768     return NULL;
  2770   oop mem_name =_member_names->get_member_name(index);
  2771   return mem_name;
  2774 // -----------------------------------------------------------------------------------------------------
  2775 // Printing
  2777 #ifndef PRODUCT
  2779 #define BULLET  " - "
  2781 static const char* state_names[] = {
  2782   "allocated", "loaded", "linked", "being_initialized", "fully_initialized", "initialization_error"
  2783 };
  2785 void InstanceKlass::print_on(outputStream* st) const {
  2786   assert(is_klass(), "must be klass");
  2787   Klass::print_on(st);
  2789   st->print(BULLET"instance size:     %d", size_helper());                        st->cr();
  2790   st->print(BULLET"klass size:        %d", size());                               st->cr();
  2791   st->print(BULLET"access:            "); access_flags().print_on(st);            st->cr();
  2792   st->print(BULLET"state:             "); st->print_cr(state_names[_init_state]);
  2793   st->print(BULLET"name:              "); name()->print_value_on(st);             st->cr();
  2794   st->print(BULLET"super:             "); super()->print_value_on_maybe_null(st); st->cr();
  2795   st->print(BULLET"sub:               ");
  2796   Klass* sub = subklass();
  2797   int n;
  2798   for (n = 0; sub != NULL; n++, sub = sub->next_sibling()) {
  2799     if (n < MaxSubklassPrintSize) {
  2800       sub->print_value_on(st);
  2801       st->print("   ");
  2804   if (n >= MaxSubklassPrintSize) st->print("(%d more klasses...)", n - MaxSubklassPrintSize);
  2805   st->cr();
  2807   if (is_interface()) {
  2808     st->print_cr(BULLET"nof implementors:  %d", nof_implementors());
  2809     if (nof_implementors() == 1) {
  2810       st->print_cr(BULLET"implementor:    ");
  2811       st->print("   ");
  2812       implementor()->print_value_on(st);
  2813       st->cr();
  2817   st->print(BULLET"arrays:            "); array_klasses()->print_value_on_maybe_null(st); st->cr();
  2818   st->print(BULLET"methods:           "); methods()->print_value_on(st);                  st->cr();
  2819   if (Verbose) {
  2820     Array<Method*>* method_array = methods();
  2821     for(int i = 0; i < method_array->length(); i++) {
  2822       st->print("%d : ", i); method_array->at(i)->print_value(); st->cr();
  2825   st->print(BULLET"method ordering:   "); method_ordering()->print_value_on(st);       st->cr();
  2826   st->print(BULLET"local interfaces:  "); local_interfaces()->print_value_on(st);      st->cr();
  2827   st->print(BULLET"trans. interfaces: "); transitive_interfaces()->print_value_on(st); st->cr();
  2828   st->print(BULLET"constants:         "); constants()->print_value_on(st);         st->cr();
  2829   if (class_loader_data() != NULL) {
  2830     st->print(BULLET"class loader data:  ");
  2831     class_loader_data()->print_value_on(st);
  2832     st->cr();
  2834   st->print(BULLET"host class:        "); host_klass()->print_value_on_maybe_null(st); st->cr();
  2835   if (source_file_name() != NULL) {
  2836     st->print(BULLET"source file:       ");
  2837     source_file_name()->print_value_on(st);
  2838     st->cr();
  2840   if (source_debug_extension() != NULL) {
  2841     st->print(BULLET"source debug extension:       ");
  2842     st->print("%s", source_debug_extension());
  2843     st->cr();
  2845   st->print(BULLET"class annotations:       "); class_annotations()->print_value_on(st); st->cr();
  2846   st->print(BULLET"class type annotations:  "); class_type_annotations()->print_value_on(st); st->cr();
  2847   st->print(BULLET"field annotations:       "); fields_annotations()->print_value_on(st); st->cr();
  2848   st->print(BULLET"field type annotations:  "); fields_type_annotations()->print_value_on(st); st->cr();
  2850     bool have_pv = false;
  2851     PreviousVersionWalker pvw(Thread::current(), (InstanceKlass*)this);
  2852     for (PreviousVersionNode * pv_node = pvw.next_previous_version();
  2853          pv_node != NULL; pv_node = pvw.next_previous_version()) {
  2854       if (!have_pv)
  2855         st->print(BULLET"previous version:  ");
  2856       have_pv = true;
  2857       pv_node->prev_constant_pool()->print_value_on(st);
  2859     if (have_pv) st->cr();
  2860   } // pvw is cleaned up
  2862   if (generic_signature() != NULL) {
  2863     st->print(BULLET"generic signature: ");
  2864     generic_signature()->print_value_on(st);
  2865     st->cr();
  2867   st->print(BULLET"inner classes:     "); inner_classes()->print_value_on(st);     st->cr();
  2868   st->print(BULLET"java mirror:       "); java_mirror()->print_value_on(st);       st->cr();
  2869   st->print(BULLET"vtable length      %d  (start addr: " INTPTR_FORMAT ")", vtable_length(), start_of_vtable());  st->cr();
  2870   st->print(BULLET"itable length      %d (start addr: " INTPTR_FORMAT ")", itable_length(), start_of_itable()); st->cr();
  2871   st->print_cr(BULLET"---- static fields (%d words):", static_field_size());
  2872   FieldPrinter print_static_field(st);
  2873   ((InstanceKlass*)this)->do_local_static_fields(&print_static_field);
  2874   st->print_cr(BULLET"---- non-static fields (%d words):", nonstatic_field_size());
  2875   FieldPrinter print_nonstatic_field(st);
  2876   ((InstanceKlass*)this)->do_nonstatic_fields(&print_nonstatic_field);
  2878   st->print(BULLET"non-static oop maps: ");
  2879   OopMapBlock* map     = start_of_nonstatic_oop_maps();
  2880   OopMapBlock* end_map = map + nonstatic_oop_map_count();
  2881   while (map < end_map) {
  2882     st->print("%d-%d ", map->offset(), map->offset() + heapOopSize*(map->count() - 1));
  2883     map++;
  2885   st->cr();
  2888 #endif //PRODUCT
  2890 void InstanceKlass::print_value_on(outputStream* st) const {
  2891   assert(is_klass(), "must be klass");
  2892   name()->print_value_on(st);
  2895 #ifndef PRODUCT
  2897 void FieldPrinter::do_field(fieldDescriptor* fd) {
  2898   _st->print(BULLET);
  2899    if (_obj == NULL) {
  2900      fd->print_on(_st);
  2901      _st->cr();
  2902    } else {
  2903      fd->print_on_for(_st, _obj);
  2904      _st->cr();
  2909 void InstanceKlass::oop_print_on(oop obj, outputStream* st) {
  2910   Klass::oop_print_on(obj, st);
  2912   if (this == SystemDictionary::String_klass()) {
  2913     typeArrayOop value  = java_lang_String::value(obj);
  2914     juint        offset = java_lang_String::offset(obj);
  2915     juint        length = java_lang_String::length(obj);
  2916     if (value != NULL &&
  2917         value->is_typeArray() &&
  2918         offset          <= (juint) value->length() &&
  2919         offset + length <= (juint) value->length()) {
  2920       st->print(BULLET"string: ");
  2921       Handle h_obj(obj);
  2922       java_lang_String::print(h_obj, st);
  2923       st->cr();
  2924       if (!WizardMode)  return;  // that is enough
  2928   st->print_cr(BULLET"---- fields (total size %d words):", oop_size(obj));
  2929   FieldPrinter print_field(st, obj);
  2930   do_nonstatic_fields(&print_field);
  2932   if (this == SystemDictionary::Class_klass()) {
  2933     st->print(BULLET"signature: ");
  2934     java_lang_Class::print_signature(obj, st);
  2935     st->cr();
  2936     Klass* mirrored_klass = java_lang_Class::as_Klass(obj);
  2937     st->print(BULLET"fake entry for mirror: ");
  2938     mirrored_klass->print_value_on_maybe_null(st);
  2939     st->cr();
  2940     Klass* array_klass = java_lang_Class::array_klass(obj);
  2941     st->print(BULLET"fake entry for array: ");
  2942     array_klass->print_value_on_maybe_null(st);
  2943     st->cr();
  2944     st->print_cr(BULLET"fake entry for oop_size: %d", java_lang_Class::oop_size(obj));
  2945     st->print_cr(BULLET"fake entry for static_oop_field_count: %d", java_lang_Class::static_oop_field_count(obj));
  2946     Klass* real_klass = java_lang_Class::as_Klass(obj);
  2947     if (real_klass != NULL && real_klass->oop_is_instance()) {
  2948       InstanceKlass::cast(real_klass)->do_local_static_fields(&print_field);
  2950   } else if (this == SystemDictionary::MethodType_klass()) {
  2951     st->print(BULLET"signature: ");
  2952     java_lang_invoke_MethodType::print_signature(obj, st);
  2953     st->cr();
  2957 #endif //PRODUCT
  2959 void InstanceKlass::oop_print_value_on(oop obj, outputStream* st) {
  2960   st->print("a ");
  2961   name()->print_value_on(st);
  2962   obj->print_address_on(st);
  2963   if (this == SystemDictionary::String_klass()
  2964       && java_lang_String::value(obj) != NULL) {
  2965     ResourceMark rm;
  2966     int len = java_lang_String::length(obj);
  2967     int plen = (len < 24 ? len : 12);
  2968     char* str = java_lang_String::as_utf8_string(obj, 0, plen);
  2969     st->print(" = \"%s\"", str);
  2970     if (len > plen)
  2971       st->print("...[%d]", len);
  2972   } else if (this == SystemDictionary::Class_klass()) {
  2973     Klass* k = java_lang_Class::as_Klass(obj);
  2974     st->print(" = ");
  2975     if (k != NULL) {
  2976       k->print_value_on(st);
  2977     } else {
  2978       const char* tname = type2name(java_lang_Class::primitive_type(obj));
  2979       st->print("%s", tname ? tname : "type?");
  2981   } else if (this == SystemDictionary::MethodType_klass()) {
  2982     st->print(" = ");
  2983     java_lang_invoke_MethodType::print_signature(obj, st);
  2984   } else if (java_lang_boxing_object::is_instance(obj)) {
  2985     st->print(" = ");
  2986     java_lang_boxing_object::print(obj, st);
  2987   } else if (this == SystemDictionary::LambdaForm_klass()) {
  2988     oop vmentry = java_lang_invoke_LambdaForm::vmentry(obj);
  2989     if (vmentry != NULL) {
  2990       st->print(" => ");
  2991       vmentry->print_value_on(st);
  2993   } else if (this == SystemDictionary::MemberName_klass()) {
  2994     Metadata* vmtarget = java_lang_invoke_MemberName::vmtarget(obj);
  2995     if (vmtarget != NULL) {
  2996       st->print(" = ");
  2997       vmtarget->print_value_on(st);
  2998     } else {
  2999       java_lang_invoke_MemberName::clazz(obj)->print_value_on(st);
  3000       st->print(".");
  3001       java_lang_invoke_MemberName::name(obj)->print_value_on(st);
  3006 const char* InstanceKlass::internal_name() const {
  3007   return external_name();
  3010 #if INCLUDE_SERVICES
  3011 // Size Statistics
  3012 void InstanceKlass::collect_statistics(KlassSizeStats *sz) const {
  3013   Klass::collect_statistics(sz);
  3015   sz->_inst_size  = HeapWordSize * size_helper();
  3016   sz->_vtab_bytes = HeapWordSize * align_object_offset(vtable_length());
  3017   sz->_itab_bytes = HeapWordSize * align_object_offset(itable_length());
  3018   sz->_nonstatic_oopmap_bytes = HeapWordSize *
  3019         ((is_interface() || is_anonymous()) ?
  3020          align_object_offset(nonstatic_oop_map_size()) :
  3021          nonstatic_oop_map_size());
  3023   int n = 0;
  3024   n += (sz->_methods_array_bytes         = sz->count_array(methods()));
  3025   n += (sz->_method_ordering_bytes       = sz->count_array(method_ordering()));
  3026   n += (sz->_local_interfaces_bytes      = sz->count_array(local_interfaces()));
  3027   n += (sz->_transitive_interfaces_bytes = sz->count_array(transitive_interfaces()));
  3028   n += (sz->_fields_bytes                = sz->count_array(fields()));
  3029   n += (sz->_inner_classes_bytes         = sz->count_array(inner_classes()));
  3030   sz->_ro_bytes += n;
  3032   const ConstantPool* cp = constants();
  3033   if (cp) {
  3034     cp->collect_statistics(sz);
  3037   const Annotations* anno = annotations();
  3038   if (anno) {
  3039     anno->collect_statistics(sz);
  3042   const Array<Method*>* methods_array = methods();
  3043   if (methods()) {
  3044     for (int i = 0; i < methods_array->length(); i++) {
  3045       Method* method = methods_array->at(i);
  3046       if (method) {
  3047         sz->_method_count ++;
  3048         method->collect_statistics(sz);
  3053 #endif // INCLUDE_SERVICES
  3055 // Verification
  3057 class VerifyFieldClosure: public OopClosure {
  3058  protected:
  3059   template <class T> void do_oop_work(T* p) {
  3060     oop obj = oopDesc::load_decode_heap_oop(p);
  3061     if (!obj->is_oop_or_null()) {
  3062       tty->print_cr("Failed: " PTR_FORMAT " -> " PTR_FORMAT, p, (address)obj);
  3063       Universe::print();
  3064       guarantee(false, "boom");
  3067  public:
  3068   virtual void do_oop(oop* p)       { VerifyFieldClosure::do_oop_work(p); }
  3069   virtual void do_oop(narrowOop* p) { VerifyFieldClosure::do_oop_work(p); }
  3070 };
  3072 void InstanceKlass::verify_on(outputStream* st, bool check_dictionary) {
  3073 #ifndef PRODUCT
  3074   // Avoid redundant verifies, this really should be in product.
  3075   if (_verify_count == Universe::verify_count()) return;
  3076   _verify_count = Universe::verify_count();
  3077 #endif
  3079   // Verify Klass
  3080   Klass::verify_on(st, check_dictionary);
  3082   // Verify that klass is present in SystemDictionary if not already
  3083   // verifying the SystemDictionary.
  3084   if (is_loaded() && !is_anonymous() && check_dictionary) {
  3085     Symbol* h_name = name();
  3086     SystemDictionary::verify_obj_klass_present(h_name, class_loader_data());
  3089   // Verify vtables
  3090   if (is_linked()) {
  3091     ResourceMark rm;
  3092     // $$$ This used to be done only for m/s collections.  Doing it
  3093     // always seemed a valid generalization.  (DLD -- 6/00)
  3094     vtable()->verify(st);
  3097   // Verify first subklass
  3098   if (subklass_oop() != NULL) {
  3099     guarantee(subklass_oop()->is_klass(), "should be klass");
  3102   // Verify siblings
  3103   Klass* super = this->super();
  3104   Klass* sib = next_sibling();
  3105   if (sib != NULL) {
  3106     if (sib == this) {
  3107       fatal(err_msg("subclass points to itself " PTR_FORMAT, sib));
  3110     guarantee(sib->is_klass(), "should be klass");
  3111     guarantee(sib->super() == super, "siblings should have same superklass");
  3114   // Verify implementor fields
  3115   Klass* im = implementor();
  3116   if (im != NULL) {
  3117     guarantee(is_interface(), "only interfaces should have implementor set");
  3118     guarantee(im->is_klass(), "should be klass");
  3119     guarantee(!im->is_interface() || im == this,
  3120       "implementors cannot be interfaces");
  3123   // Verify local interfaces
  3124   if (local_interfaces()) {
  3125     Array<Klass*>* local_interfaces = this->local_interfaces();
  3126     for (int j = 0; j < local_interfaces->length(); j++) {
  3127       Klass* e = local_interfaces->at(j);
  3128       guarantee(e->is_klass() && e->is_interface(), "invalid local interface");
  3132   // Verify transitive interfaces
  3133   if (transitive_interfaces() != NULL) {
  3134     Array<Klass*>* transitive_interfaces = this->transitive_interfaces();
  3135     for (int j = 0; j < transitive_interfaces->length(); j++) {
  3136       Klass* e = transitive_interfaces->at(j);
  3137       guarantee(e->is_klass() && e->is_interface(), "invalid transitive interface");
  3141   // Verify methods
  3142   if (methods() != NULL) {
  3143     Array<Method*>* methods = this->methods();
  3144     for (int j = 0; j < methods->length(); j++) {
  3145       guarantee(methods->at(j)->is_method(), "non-method in methods array");
  3147     for (int j = 0; j < methods->length() - 1; j++) {
  3148       Method* m1 = methods->at(j);
  3149       Method* m2 = methods->at(j + 1);
  3150       guarantee(m1->name()->fast_compare(m2->name()) <= 0, "methods not sorted correctly");
  3154   // Verify method ordering
  3155   if (method_ordering() != NULL) {
  3156     Array<int>* method_ordering = this->method_ordering();
  3157     int length = method_ordering->length();
  3158     if (JvmtiExport::can_maintain_original_method_order() ||
  3159         ((UseSharedSpaces || DumpSharedSpaces) && length != 0)) {
  3160       guarantee(length == methods()->length(), "invalid method ordering length");
  3161       jlong sum = 0;
  3162       for (int j = 0; j < length; j++) {
  3163         int original_index = method_ordering->at(j);
  3164         guarantee(original_index >= 0, "invalid method ordering index");
  3165         guarantee(original_index < length, "invalid method ordering index");
  3166         sum += original_index;
  3168       // Verify sum of indices 0,1,...,length-1
  3169       guarantee(sum == ((jlong)length*(length-1))/2, "invalid method ordering sum");
  3170     } else {
  3171       guarantee(length == 0, "invalid method ordering length");
  3175   // Verify JNI static field identifiers
  3176   if (jni_ids() != NULL) {
  3177     jni_ids()->verify(this);
  3180   // Verify other fields
  3181   if (array_klasses() != NULL) {
  3182     guarantee(array_klasses()->is_klass(), "should be klass");
  3184   if (constants() != NULL) {
  3185     guarantee(constants()->is_constantPool(), "should be constant pool");
  3187   const Klass* host = host_klass();
  3188   if (host != NULL) {
  3189     guarantee(host->is_klass(), "should be klass");
  3193 void InstanceKlass::oop_verify_on(oop obj, outputStream* st) {
  3194   Klass::oop_verify_on(obj, st);
  3195   VerifyFieldClosure blk;
  3196   obj->oop_iterate_no_header(&blk);
  3200 // JNIid class for jfieldIDs only
  3201 // Note to reviewers:
  3202 // These JNI functions are just moved over to column 1 and not changed
  3203 // in the compressed oops workspace.
  3204 JNIid::JNIid(Klass* holder, int offset, JNIid* next) {
  3205   _holder = holder;
  3206   _offset = offset;
  3207   _next = next;
  3208   debug_only(_is_static_field_id = false;)
  3212 JNIid* JNIid::find(int offset) {
  3213   JNIid* current = this;
  3214   while (current != NULL) {
  3215     if (current->offset() == offset) return current;
  3216     current = current->next();
  3218   return NULL;
  3221 void JNIid::deallocate(JNIid* current) {
  3222   while (current != NULL) {
  3223     JNIid* next = current->next();
  3224     delete current;
  3225     current = next;
  3230 void JNIid::verify(Klass* holder) {
  3231   int first_field_offset  = InstanceMirrorKlass::offset_of_static_fields();
  3232   int end_field_offset;
  3233   end_field_offset = first_field_offset + (InstanceKlass::cast(holder)->static_field_size() * wordSize);
  3235   JNIid* current = this;
  3236   while (current != NULL) {
  3237     guarantee(current->holder() == holder, "Invalid klass in JNIid");
  3238 #ifdef ASSERT
  3239     int o = current->offset();
  3240     if (current->is_static_field_id()) {
  3241       guarantee(o >= first_field_offset  && o < end_field_offset,  "Invalid static field offset in JNIid");
  3243 #endif
  3244     current = current->next();
  3249 #ifdef ASSERT
  3250 void InstanceKlass::set_init_state(ClassState state) {
  3251   bool good_state = is_shared() ? (_init_state <= state)
  3252                                                : (_init_state < state);
  3253   assert(good_state || state == allocated, "illegal state transition");
  3254   _init_state = (u1)state;
  3256 #endif
  3259 // RedefineClasses() support for previous versions:
  3261 // Purge previous versions
  3262 static void purge_previous_versions_internal(InstanceKlass* ik, int emcp_method_count) {
  3263   if (ik->previous_versions() != NULL) {
  3264     // This klass has previous versions so see what we can cleanup
  3265     // while it is safe to do so.
  3267     int deleted_count = 0;    // leave debugging breadcrumbs
  3268     int live_count = 0;
  3269     ClassLoaderData* loader_data = ik->class_loader_data() == NULL ?
  3270                        ClassLoaderData::the_null_class_loader_data() :
  3271                        ik->class_loader_data();
  3273     // RC_TRACE macro has an embedded ResourceMark
  3274     RC_TRACE(0x00000200, ("purge: %s: previous version length=%d",
  3275       ik->external_name(), ik->previous_versions()->length()));
  3277     for (int i = ik->previous_versions()->length() - 1; i >= 0; i--) {
  3278       // check the previous versions array
  3279       PreviousVersionNode * pv_node = ik->previous_versions()->at(i);
  3280       ConstantPool* cp_ref = pv_node->prev_constant_pool();
  3281       assert(cp_ref != NULL, "cp ref was unexpectedly cleared");
  3283       ConstantPool* pvcp = cp_ref;
  3284       if (!pvcp->on_stack()) {
  3285         // If the constant pool isn't on stack, none of the methods
  3286         // are executing.  Delete all the methods, the constant pool and
  3287         // and this previous version node.
  3288         GrowableArray<Method*>* method_refs = pv_node->prev_EMCP_methods();
  3289         if (method_refs != NULL) {
  3290           for (int j = method_refs->length() - 1; j >= 0; j--) {
  3291             Method* method = method_refs->at(j);
  3292             assert(method != NULL, "method ref was unexpectedly cleared");
  3293             method_refs->remove_at(j);
  3294             // method will be freed with associated class.
  3297         // Remove the constant pool
  3298         delete pv_node;
  3299         // Since we are traversing the array backwards, we don't have to
  3300         // do anything special with the index.
  3301         ik->previous_versions()->remove_at(i);
  3302         deleted_count++;
  3303         continue;
  3304       } else {
  3305         RC_TRACE(0x00000200, ("purge: previous version @%d is alive", i));
  3306         assert(pvcp->pool_holder() != NULL, "Constant pool with no holder");
  3307         guarantee (!loader_data->is_unloading(), "unloaded classes can't be on the stack");
  3308         live_count++;
  3311       // At least one method is live in this previous version, clean out
  3312       // the others or mark them as obsolete.
  3313       GrowableArray<Method*>* method_refs = pv_node->prev_EMCP_methods();
  3314       if (method_refs != NULL) {
  3315         RC_TRACE(0x00000200, ("purge: previous methods length=%d",
  3316           method_refs->length()));
  3317         for (int j = method_refs->length() - 1; j >= 0; j--) {
  3318           Method* method = method_refs->at(j);
  3319           assert(method != NULL, "method ref was unexpectedly cleared");
  3321           // Remove the emcp method if it's not executing
  3322           // If it's been made obsolete by a redefinition of a non-emcp
  3323           // method, mark it as obsolete but leave it to clean up later.
  3324           if (!method->on_stack()) {
  3325             method_refs->remove_at(j);
  3326           } else if (emcp_method_count == 0) {
  3327             method->set_is_obsolete();
  3328           } else {
  3329             // RC_TRACE macro has an embedded ResourceMark
  3330             RC_TRACE(0x00000200,
  3331               ("purge: %s(%s): prev method @%d in version @%d is alive",
  3332               method->name()->as_C_string(),
  3333               method->signature()->as_C_string(), j, i));
  3338     assert(ik->previous_versions()->length() == live_count, "sanity check");
  3339     RC_TRACE(0x00000200,
  3340       ("purge: previous version stats: live=%d, deleted=%d", live_count,
  3341       deleted_count));
  3345 // External interface for use during class unloading.
  3346 void InstanceKlass::purge_previous_versions(InstanceKlass* ik) {
  3347   // Call with >0 emcp methods since they are not currently being redefined.
  3348   purge_previous_versions_internal(ik, 1);
  3352 // Potentially add an information node that contains pointers to the
  3353 // interesting parts of the previous version of the_class.
  3354 // This is also where we clean out any unused references.
  3355 // Note that while we delete nodes from the _previous_versions
  3356 // array, we never delete the array itself until the klass is
  3357 // unloaded. The has_been_redefined() query depends on that fact.
  3358 //
  3359 void InstanceKlass::add_previous_version(instanceKlassHandle ikh,
  3360        BitMap* emcp_methods, int emcp_method_count) {
  3361   assert(Thread::current()->is_VM_thread(),
  3362          "only VMThread can add previous versions");
  3364   if (_previous_versions == NULL) {
  3365     // This is the first previous version so make some space.
  3366     // Start with 2 elements under the assumption that the class
  3367     // won't be redefined much.
  3368     _previous_versions =  new (ResourceObj::C_HEAP, mtClass)
  3369                             GrowableArray<PreviousVersionNode *>(2, true);
  3372   ConstantPool* cp_ref = ikh->constants();
  3374   // RC_TRACE macro has an embedded ResourceMark
  3375   RC_TRACE(0x00000400, ("adding previous version ref for %s @%d, EMCP_cnt=%d "
  3376                         "on_stack=%d",
  3377     ikh->external_name(), _previous_versions->length(), emcp_method_count,
  3378     cp_ref->on_stack()));
  3380   // If the constant pool for this previous version of the class
  3381   // is not marked as being on the stack, then none of the methods
  3382   // in this previous version of the class are on the stack so
  3383   // we don't need to create a new PreviousVersionNode. However,
  3384   // we still need to examine older previous versions below.
  3385   Array<Method*>* old_methods = ikh->methods();
  3387   if (cp_ref->on_stack()) {
  3388     PreviousVersionNode * pv_node = NULL;
  3389     if (emcp_method_count == 0) {
  3390       // non-shared ConstantPool gets a reference
  3391       pv_node = new PreviousVersionNode(cp_ref, NULL);
  3392       RC_TRACE(0x00000400,
  3393           ("add: all methods are obsolete; flushing any EMCP refs"));
  3394     } else {
  3395       int local_count = 0;
  3396       GrowableArray<Method*>* method_refs = new (ResourceObj::C_HEAP, mtClass)
  3397           GrowableArray<Method*>(emcp_method_count, true);
  3398       for (int i = 0; i < old_methods->length(); i++) {
  3399         if (emcp_methods->at(i)) {
  3400             // this old method is EMCP. Save it only if it's on the stack
  3401             Method* old_method = old_methods->at(i);
  3402             if (old_method->on_stack()) {
  3403               method_refs->append(old_method);
  3405           if (++local_count >= emcp_method_count) {
  3406             // no more EMCP methods so bail out now
  3407             break;
  3411       // non-shared ConstantPool gets a reference
  3412       pv_node = new PreviousVersionNode(cp_ref, method_refs);
  3414     // append new previous version.
  3415     _previous_versions->append(pv_node);
  3418   // Since the caller is the VMThread and we are at a safepoint, this
  3419   // is a good time to clear out unused references.
  3421   RC_TRACE(0x00000400, ("add: previous version length=%d",
  3422     _previous_versions->length()));
  3424   // Purge previous versions not executing on the stack
  3425   purge_previous_versions_internal(this, emcp_method_count);
  3427   int obsolete_method_count = old_methods->length() - emcp_method_count;
  3429   if (emcp_method_count != 0 && obsolete_method_count != 0 &&
  3430       _previous_versions->length() > 0) {
  3431     // We have a mix of obsolete and EMCP methods so we have to
  3432     // clear out any matching EMCP method entries the hard way.
  3433     int local_count = 0;
  3434     for (int i = 0; i < old_methods->length(); i++) {
  3435       if (!emcp_methods->at(i)) {
  3436         // only obsolete methods are interesting
  3437         Method* old_method = old_methods->at(i);
  3438         Symbol* m_name = old_method->name();
  3439         Symbol* m_signature = old_method->signature();
  3441         // we might not have added the last entry
  3442         for (int j = _previous_versions->length() - 1; j >= 0; j--) {
  3443           // check the previous versions array for non executing obsolete methods
  3444           PreviousVersionNode * pv_node = _previous_versions->at(j);
  3446           GrowableArray<Method*>* method_refs = pv_node->prev_EMCP_methods();
  3447           if (method_refs == NULL) {
  3448             // We have run into a PreviousVersion generation where
  3449             // all methods were made obsolete during that generation's
  3450             // RedefineClasses() operation. At the time of that
  3451             // operation, all EMCP methods were flushed so we don't
  3452             // have to go back any further.
  3453             //
  3454             // A NULL method_refs is different than an empty method_refs.
  3455             // We cannot infer any optimizations about older generations
  3456             // from an empty method_refs for the current generation.
  3457             break;
  3460           for (int k = method_refs->length() - 1; k >= 0; k--) {
  3461             Method* method = method_refs->at(k);
  3463             if (!method->is_obsolete() &&
  3464                 method->name() == m_name &&
  3465                 method->signature() == m_signature) {
  3466               // The current RedefineClasses() call has made all EMCP
  3467               // versions of this method obsolete so mark it as obsolete
  3468               // and remove the reference.
  3469               RC_TRACE(0x00000400,
  3470                 ("add: %s(%s): flush obsolete method @%d in version @%d",
  3471                 m_name->as_C_string(), m_signature->as_C_string(), k, j));
  3473               method->set_is_obsolete();
  3474               // Leave obsolete methods on the previous version list to
  3475               // clean up later.
  3476               break;
  3480           // The previous loop may not find a matching EMCP method, but
  3481           // that doesn't mean that we can optimize and not go any
  3482           // further back in the PreviousVersion generations. The EMCP
  3483           // method for this generation could have already been deleted,
  3484           // but there still may be an older EMCP method that has not
  3485           // been deleted.
  3488         if (++local_count >= obsolete_method_count) {
  3489           // no more obsolete methods so bail out now
  3490           break;
  3495 } // end add_previous_version()
  3498 // Determine if InstanceKlass has a previous version.
  3499 bool InstanceKlass::has_previous_version() const {
  3500   return (_previous_versions != NULL && _previous_versions->length() > 0);
  3501 } // end has_previous_version()
  3504 Method* InstanceKlass::method_with_idnum(int idnum) {
  3505   Method* m = NULL;
  3506   if (idnum < methods()->length()) {
  3507     m = methods()->at(idnum);
  3509   if (m == NULL || m->method_idnum() != idnum) {
  3510     for (int index = 0; index < methods()->length(); ++index) {
  3511       m = methods()->at(index);
  3512       if (m->method_idnum() == idnum) {
  3513         return m;
  3516     // None found, return null for the caller to handle.
  3517     return NULL;
  3519   return m;
  3522 jint InstanceKlass::get_cached_class_file_len() {
  3523   return VM_RedefineClasses::get_cached_class_file_len(_cached_class_file);
  3526 unsigned char * InstanceKlass::get_cached_class_file_bytes() {
  3527   return VM_RedefineClasses::get_cached_class_file_bytes(_cached_class_file);
  3531 // Construct a PreviousVersionNode entry for the array hung off
  3532 // the InstanceKlass.
  3533 PreviousVersionNode::PreviousVersionNode(ConstantPool* prev_constant_pool,
  3534   GrowableArray<Method*>* prev_EMCP_methods) {
  3536   _prev_constant_pool = prev_constant_pool;
  3537   _prev_EMCP_methods = prev_EMCP_methods;
  3541 // Destroy a PreviousVersionNode
  3542 PreviousVersionNode::~PreviousVersionNode() {
  3543   if (_prev_constant_pool != NULL) {
  3544     _prev_constant_pool = NULL;
  3547   if (_prev_EMCP_methods != NULL) {
  3548     delete _prev_EMCP_methods;
  3552 // Construct a helper for walking the previous versions array
  3553 PreviousVersionWalker::PreviousVersionWalker(Thread* thread, InstanceKlass *ik) {
  3554   _thread = thread;
  3555   _previous_versions = ik->previous_versions();
  3556   _current_index = 0;
  3557   _current_p = NULL;
  3558   _current_constant_pool_handle = constantPoolHandle(thread, ik->constants());
  3562 // Return the interesting information for the next previous version
  3563 // of the klass. Returns NULL if there are no more previous versions.
  3564 PreviousVersionNode* PreviousVersionWalker::next_previous_version() {
  3565   if (_previous_versions == NULL) {
  3566     // no previous versions so nothing to return
  3567     return NULL;
  3570   _current_p = NULL;  // reset to NULL
  3571   _current_constant_pool_handle = NULL;
  3573   int length = _previous_versions->length();
  3575   while (_current_index < length) {
  3576     PreviousVersionNode * pv_node = _previous_versions->at(_current_index++);
  3578     // Save a handle to the constant pool for this previous version,
  3579     // which keeps all the methods from being deallocated.
  3580     _current_constant_pool_handle = constantPoolHandle(_thread, pv_node->prev_constant_pool());
  3581     _current_p = pv_node;
  3582     return pv_node;
  3585   return NULL;
  3586 } // end next_previous_version()

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