/* * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. * */ #include "precompiled.hpp" #include "classfile/javaClasses.hpp" #include "classfile/systemDictionary.hpp" #include "classfile/verifier.hpp" #include "classfile/vmSymbols.hpp" #include "compiler/compileBroker.hpp" #include "gc_implementation/shared/markSweep.inline.hpp" #include "gc_interface/collectedHeap.inline.hpp" #include "interpreter/oopMapCache.hpp" #include "interpreter/rewriter.hpp" #include "jvmtifiles/jvmti.h" #include "memory/genOopClosures.inline.hpp" #include "memory/heapInspection.hpp" #include "memory/iterator.inline.hpp" #include "memory/metadataFactory.hpp" #include "memory/oopFactory.hpp" #include "oops/fieldStreams.hpp" #include "oops/instanceClassLoaderKlass.hpp" #include "oops/instanceKlass.hpp" #include "oops/instanceMirrorKlass.hpp" #include "oops/instanceOop.hpp" #include "oops/klass.inline.hpp" #include "oops/method.hpp" #include "oops/oop.inline.hpp" #include "oops/symbol.hpp" #include "prims/jvmtiExport.hpp" #include "prims/jvmtiRedefineClassesTrace.hpp" #include "prims/jvmtiRedefineClasses.hpp" #include "prims/methodComparator.hpp" #include "runtime/fieldDescriptor.hpp" #include "runtime/handles.inline.hpp" #include "runtime/javaCalls.hpp" #include "runtime/mutexLocker.hpp" #include "runtime/orderAccess.inline.hpp" #include "runtime/thread.inline.hpp" #include "services/classLoadingService.hpp" #include "services/threadService.hpp" #include "utilities/dtrace.hpp" #include "utilities/macros.hpp" #if INCLUDE_ALL_GCS #include "gc_implementation/concurrentMarkSweep/cmsOopClosures.inline.hpp" #include "gc_implementation/g1/g1CollectedHeap.inline.hpp" #include "gc_implementation/g1/g1OopClosures.inline.hpp" #include "gc_implementation/g1/g1RemSet.inline.hpp" #include "gc_implementation/g1/heapRegionSeq.inline.hpp" #include "gc_implementation/parNew/parOopClosures.inline.hpp" #include "gc_implementation/parallelScavenge/parallelScavengeHeap.inline.hpp" #include "gc_implementation/parallelScavenge/psPromotionManager.inline.hpp" #include "gc_implementation/parallelScavenge/psScavenge.inline.hpp" #include "oops/oop.pcgc.inline.hpp" #endif // INCLUDE_ALL_GCS #ifdef COMPILER1 #include "c1/c1_Compiler.hpp" #endif PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC #ifdef DTRACE_ENABLED #ifndef USDT2 HS_DTRACE_PROBE_DECL4(hotspot, class__initialization__required, char*, intptr_t, oop, intptr_t); HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__recursive, char*, intptr_t, oop, intptr_t, int); HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__concurrent, char*, intptr_t, oop, intptr_t, int); HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__erroneous, char*, intptr_t, oop, intptr_t, int); HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__super__failed, char*, intptr_t, oop, intptr_t, int); HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__clinit, char*, intptr_t, oop, intptr_t, int); HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__error, char*, intptr_t, oop, intptr_t, int); HS_DTRACE_PROBE_DECL5(hotspot, class__initialization__end, char*, intptr_t, oop, intptr_t, int); #define DTRACE_CLASSINIT_PROBE(type, clss, thread_type) \ { \ char* data = NULL; \ int len = 0; \ Symbol* name = (clss)->name(); \ if (name != NULL) { \ data = (char*)name->bytes(); \ len = name->utf8_length(); \ } \ HS_DTRACE_PROBE4(hotspot, class__initialization__##type, \ data, len, SOLARIS_ONLY((void *))(clss)->class_loader(), thread_type); \ } #define DTRACE_CLASSINIT_PROBE_WAIT(type, clss, thread_type, wait) \ { \ char* data = NULL; \ int len = 0; \ Symbol* name = (clss)->name(); \ if (name != NULL) { \ data = (char*)name->bytes(); \ len = name->utf8_length(); \ } \ HS_DTRACE_PROBE5(hotspot, class__initialization__##type, \ data, len, SOLARIS_ONLY((void *))(clss)->class_loader(), thread_type, wait); \ } #else /* USDT2 */ #define HOTSPOT_CLASS_INITIALIZATION_required HOTSPOT_CLASS_INITIALIZATION_REQUIRED #define HOTSPOT_CLASS_INITIALIZATION_recursive HOTSPOT_CLASS_INITIALIZATION_RECURSIVE #define HOTSPOT_CLASS_INITIALIZATION_concurrent HOTSPOT_CLASS_INITIALIZATION_CONCURRENT #define HOTSPOT_CLASS_INITIALIZATION_erroneous HOTSPOT_CLASS_INITIALIZATION_ERRONEOUS #define HOTSPOT_CLASS_INITIALIZATION_super__failed HOTSPOT_CLASS_INITIALIZATION_SUPER_FAILED #define HOTSPOT_CLASS_INITIALIZATION_clinit HOTSPOT_CLASS_INITIALIZATION_CLINIT #define HOTSPOT_CLASS_INITIALIZATION_error HOTSPOT_CLASS_INITIALIZATION_ERROR #define HOTSPOT_CLASS_INITIALIZATION_end HOTSPOT_CLASS_INITIALIZATION_END #define DTRACE_CLASSINIT_PROBE(type, clss, thread_type) \ { \ char* data = NULL; \ int len = 0; \ Symbol* name = (clss)->name(); \ if (name != NULL) { \ data = (char*)name->bytes(); \ len = name->utf8_length(); \ } \ HOTSPOT_CLASS_INITIALIZATION_##type( \ data, len, (clss)->class_loader(), thread_type); \ } #define DTRACE_CLASSINIT_PROBE_WAIT(type, clss, thread_type, wait) \ { \ char* data = NULL; \ int len = 0; \ Symbol* name = (clss)->name(); \ if (name != NULL) { \ data = (char*)name->bytes(); \ len = name->utf8_length(); \ } \ HOTSPOT_CLASS_INITIALIZATION_##type( \ data, len, (clss)->class_loader(), thread_type, wait); \ } #endif /* USDT2 */ #else // ndef DTRACE_ENABLED #define DTRACE_CLASSINIT_PROBE(type, clss, thread_type) #define DTRACE_CLASSINIT_PROBE_WAIT(type, clss, thread_type, wait) #endif // ndef DTRACE_ENABLED volatile int InstanceKlass::_total_instanceKlass_count = 0; InstanceKlass* InstanceKlass::allocate_instance_klass( ClassLoaderData* loader_data, int vtable_len, int itable_len, int static_field_size, int nonstatic_oop_map_size, ReferenceType rt, AccessFlags access_flags, Symbol* name, Klass* super_klass, bool is_anonymous, TRAPS) { int size = InstanceKlass::size(vtable_len, itable_len, nonstatic_oop_map_size, access_flags.is_interface(), is_anonymous); // Allocation InstanceKlass* ik; if (rt == REF_NONE) { if (name == vmSymbols::java_lang_Class()) { ik = new (loader_data, size, THREAD) InstanceMirrorKlass( vtable_len, itable_len, static_field_size, nonstatic_oop_map_size, rt, access_flags, is_anonymous); } else if (name == vmSymbols::java_lang_ClassLoader() || (SystemDictionary::ClassLoader_klass_loaded() && super_klass != NULL && super_klass->is_subtype_of(SystemDictionary::ClassLoader_klass()))) { ik = new (loader_data, size, THREAD) InstanceClassLoaderKlass( vtable_len, itable_len, static_field_size, nonstatic_oop_map_size, rt, access_flags, is_anonymous); } else { // normal class ik = new (loader_data, size, THREAD) InstanceKlass( vtable_len, itable_len, static_field_size, nonstatic_oop_map_size, rt, access_flags, is_anonymous); } } else { // reference klass ik = new (loader_data, size, THREAD) InstanceRefKlass( vtable_len, itable_len, static_field_size, nonstatic_oop_map_size, rt, access_flags, is_anonymous); } // Check for pending exception before adding to the loader data and incrementing // class count. Can get OOM here. if (HAS_PENDING_EXCEPTION) { return NULL; } // Add all classes to our internal class loader list here, // including classes in the bootstrap (NULL) class loader. loader_data->add_class(ik); Atomic::inc(&_total_instanceKlass_count); return ik; } // copy method ordering from resource area to Metaspace void InstanceKlass::copy_method_ordering(intArray* m, TRAPS) { if (m != NULL) { // allocate a new array and copy contents (memcpy?) _method_ordering = MetadataFactory::new_array(class_loader_data(), m->length(), CHECK); for (int i = 0; i < m->length(); i++) { _method_ordering->at_put(i, m->at(i)); } } else { _method_ordering = Universe::the_empty_int_array(); } } // create a new array of vtable_indices for default methods Array* InstanceKlass::create_new_default_vtable_indices(int len, TRAPS) { Array* vtable_indices = MetadataFactory::new_array(class_loader_data(), len, CHECK_NULL); assert(default_vtable_indices() == NULL, "only create once"); set_default_vtable_indices(vtable_indices); return vtable_indices; } InstanceKlass::InstanceKlass(int vtable_len, int itable_len, int static_field_size, int nonstatic_oop_map_size, ReferenceType rt, AccessFlags access_flags, bool is_anonymous) { No_Safepoint_Verifier no_safepoint; // until k becomes parsable int iksize = InstanceKlass::size(vtable_len, itable_len, nonstatic_oop_map_size, access_flags.is_interface(), is_anonymous); set_vtable_length(vtable_len); set_itable_length(itable_len); set_static_field_size(static_field_size); set_nonstatic_oop_map_size(nonstatic_oop_map_size); set_access_flags(access_flags); _misc_flags = 0; // initialize to zero set_is_anonymous(is_anonymous); assert(size() == iksize, "wrong size for object"); set_array_klasses(NULL); set_methods(NULL); set_method_ordering(NULL); set_default_methods(NULL); set_default_vtable_indices(NULL); set_local_interfaces(NULL); set_transitive_interfaces(NULL); init_implementor(); set_fields(NULL, 0); set_constants(NULL); set_class_loader_data(NULL); set_source_file_name_index(0); set_source_debug_extension(NULL, 0); set_array_name(NULL); set_inner_classes(NULL); set_static_oop_field_count(0); set_nonstatic_field_size(0); set_is_marked_dependent(false); set_has_unloaded_dependent(false); set_init_state(InstanceKlass::allocated); set_init_thread(NULL); set_reference_type(rt); set_oop_map_cache(NULL); set_jni_ids(NULL); set_osr_nmethods_head(NULL); set_breakpoints(NULL); init_previous_versions(); set_generic_signature_index(0); release_set_methods_jmethod_ids(NULL); set_annotations(NULL); set_jvmti_cached_class_field_map(NULL); set_initial_method_idnum(0); _dependencies = NULL; set_jvmti_cached_class_field_map(NULL); set_cached_class_file(NULL); set_initial_method_idnum(0); set_minor_version(0); set_major_version(0); NOT_PRODUCT(_verify_count = 0;) // initialize the non-header words to zero intptr_t* p = (intptr_t*)this; for (int index = InstanceKlass::header_size(); index < iksize; index++) { p[index] = NULL_WORD; } // Set temporary value until parseClassFile updates it with the real instance // size. set_layout_helper(Klass::instance_layout_helper(0, true)); } void InstanceKlass::deallocate_methods(ClassLoaderData* loader_data, Array* methods) { if (methods != NULL && methods != Universe::the_empty_method_array() && !methods->is_shared()) { for (int i = 0; i < methods->length(); i++) { Method* method = methods->at(i); if (method == NULL) continue; // maybe null if error processing // Only want to delete methods that are not executing for RedefineClasses. // The previous version will point to them so they're not totally dangling assert (!method->on_stack(), "shouldn't be called with methods on stack"); MetadataFactory::free_metadata(loader_data, method); } MetadataFactory::free_array(loader_data, methods); } } void InstanceKlass::deallocate_interfaces(ClassLoaderData* loader_data, Klass* super_klass, Array* local_interfaces, Array* transitive_interfaces) { // Only deallocate transitive interfaces if not empty, same as super class // or same as local interfaces. See code in parseClassFile. Array* ti = transitive_interfaces; if (ti != Universe::the_empty_klass_array() && ti != local_interfaces) { // check that the interfaces don't come from super class Array* sti = (super_klass == NULL) ? NULL : InstanceKlass::cast(super_klass)->transitive_interfaces(); if (ti != sti && ti != NULL && !ti->is_shared()) { MetadataFactory::free_array(loader_data, ti); } } // local interfaces can be empty if (local_interfaces != Universe::the_empty_klass_array() && local_interfaces != NULL && !local_interfaces->is_shared()) { MetadataFactory::free_array(loader_data, local_interfaces); } } // This function deallocates the metadata and C heap pointers that the // InstanceKlass points to. void InstanceKlass::deallocate_contents(ClassLoaderData* loader_data) { // Orphan the mirror first, CMS thinks it's still live. if (java_mirror() != NULL) { java_lang_Class::set_klass(java_mirror(), NULL); } // Need to take this class off the class loader data list. loader_data->remove_class(this); // The array_klass for this class is created later, after error handling. // For class redefinition, we keep the original class so this scratch class // doesn't have an array class. Either way, assert that there is nothing // to deallocate. assert(array_klasses() == NULL, "array classes shouldn't be created for this class yet"); // Release C heap allocated data that this might point to, which includes // reference counting symbol names. release_C_heap_structures(); deallocate_methods(loader_data, methods()); set_methods(NULL); if (method_ordering() != NULL && method_ordering() != Universe::the_empty_int_array() && !method_ordering()->is_shared()) { MetadataFactory::free_array(loader_data, method_ordering()); } set_method_ordering(NULL); // default methods can be empty if (default_methods() != NULL && default_methods() != Universe::the_empty_method_array() && !default_methods()->is_shared()) { MetadataFactory::free_array(loader_data, default_methods()); } // Do NOT deallocate the default methods, they are owned by superinterfaces. set_default_methods(NULL); // default methods vtable indices can be empty if (default_vtable_indices() != NULL && !default_vtable_indices()->is_shared()) { MetadataFactory::free_array(loader_data, default_vtable_indices()); } set_default_vtable_indices(NULL); // This array is in Klass, but remove it with the InstanceKlass since // this place would be the only caller and it can share memory with transitive // interfaces. if (secondary_supers() != NULL && secondary_supers() != Universe::the_empty_klass_array() && secondary_supers() != transitive_interfaces() && !secondary_supers()->is_shared()) { MetadataFactory::free_array(loader_data, secondary_supers()); } set_secondary_supers(NULL); deallocate_interfaces(loader_data, super(), local_interfaces(), transitive_interfaces()); set_transitive_interfaces(NULL); set_local_interfaces(NULL); if (fields() != NULL && !fields()->is_shared()) { MetadataFactory::free_array(loader_data, fields()); } set_fields(NULL, 0); // If a method from a redefined class is using this constant pool, don't // delete it, yet. The new class's previous version will point to this. if (constants() != NULL) { assert (!constants()->on_stack(), "shouldn't be called if anything is onstack"); if (!constants()->is_shared()) { MetadataFactory::free_metadata(loader_data, constants()); } set_constants(NULL); } if (inner_classes() != NULL && inner_classes() != Universe::the_empty_short_array() && !inner_classes()->is_shared()) { MetadataFactory::free_array(loader_data, inner_classes()); } set_inner_classes(NULL); // We should deallocate the Annotations instance if it's not in shared spaces. if (annotations() != NULL && !annotations()->is_shared()) { MetadataFactory::free_metadata(loader_data, annotations()); } set_annotations(NULL); } bool InstanceKlass::should_be_initialized() const { return !is_initialized(); } klassVtable* InstanceKlass::vtable() const { return new klassVtable(this, start_of_vtable(), vtable_length() / vtableEntry::size()); } klassItable* InstanceKlass::itable() const { return new klassItable(instanceKlassHandle(this)); } void InstanceKlass::eager_initialize(Thread *thread) { if (!EagerInitialization) return; if (this->is_not_initialized()) { // abort if the the class has a class initializer if (this->class_initializer() != NULL) return; // abort if it is java.lang.Object (initialization is handled in genesis) Klass* super = this->super(); if (super == NULL) return; // abort if the super class should be initialized if (!InstanceKlass::cast(super)->is_initialized()) return; // call body to expose the this pointer instanceKlassHandle this_oop(thread, this); eager_initialize_impl(this_oop); } } // JVMTI spec thinks there are signers and protection domain in the // instanceKlass. These accessors pretend these fields are there. // The hprof specification also thinks these fields are in InstanceKlass. oop InstanceKlass::protection_domain() const { // return the protection_domain from the mirror return java_lang_Class::protection_domain(java_mirror()); } // To remove these from requires an incompatible change and CCC request. objArrayOop InstanceKlass::signers() const { // return the signers from the mirror return java_lang_Class::signers(java_mirror()); } oop InstanceKlass::init_lock() const { // return the init lock from the mirror oop lock = java_lang_Class::init_lock(java_mirror()); assert((oop)lock != NULL || !is_not_initialized(), // initialized or in_error state "only fully initialized state can have a null lock"); return lock; } // Set the initialization lock to null so the object can be GC'ed. Any racing // threads to get this lock will see a null lock and will not lock. // That's okay because they all check for initialized state after getting // the lock and return. void InstanceKlass::fence_and_clear_init_lock() { // make sure previous stores are all done, notably the init_state. OrderAccess::storestore(); java_lang_Class::set_init_lock(java_mirror(), NULL); assert(!is_not_initialized(), "class must be initialized now"); } void InstanceKlass::eager_initialize_impl(instanceKlassHandle this_oop) { EXCEPTION_MARK; oop init_lock = this_oop->init_lock(); ObjectLocker ol(init_lock, THREAD, init_lock != NULL); // abort if someone beat us to the initialization if (!this_oop->is_not_initialized()) return; // note: not equivalent to is_initialized() ClassState old_state = this_oop->init_state(); link_class_impl(this_oop, true, THREAD); if (HAS_PENDING_EXCEPTION) { CLEAR_PENDING_EXCEPTION; // Abort if linking the class throws an exception. // Use a test to avoid redundantly resetting the state if there's // no change. Set_init_state() asserts that state changes make // progress, whereas here we might just be spinning in place. if( old_state != this_oop->_init_state ) this_oop->set_init_state (old_state); } else { // linking successfull, mark class as initialized this_oop->set_init_state (fully_initialized); this_oop->fence_and_clear_init_lock(); // trace if (TraceClassInitialization) { ResourceMark rm(THREAD); tty->print_cr("[Initialized %s without side effects]", this_oop->external_name()); } } } // See "The Virtual Machine Specification" section 2.16.5 for a detailed explanation of the class initialization // process. The step comments refers to the procedure described in that section. // Note: implementation moved to static method to expose the this pointer. void InstanceKlass::initialize(TRAPS) { if (this->should_be_initialized()) { HandleMark hm(THREAD); instanceKlassHandle this_oop(THREAD, this); initialize_impl(this_oop, CHECK); // Note: at this point the class may be initialized // OR it may be in the state of being initialized // in case of recursive initialization! } else { assert(is_initialized(), "sanity check"); } } bool InstanceKlass::verify_code( instanceKlassHandle this_oop, bool throw_verifyerror, TRAPS) { // 1) Verify the bytecodes Verifier::Mode mode = throw_verifyerror ? Verifier::ThrowException : Verifier::NoException; return Verifier::verify(this_oop, mode, this_oop->should_verify_class(), CHECK_false); } // Used exclusively by the shared spaces dump mechanism to prevent // classes mapped into the shared regions in new VMs from appearing linked. void InstanceKlass::unlink_class() { assert(is_linked(), "must be linked"); _init_state = loaded; } void InstanceKlass::link_class(TRAPS) { assert(is_loaded(), "must be loaded"); if (!is_linked()) { HandleMark hm(THREAD); instanceKlassHandle this_oop(THREAD, this); link_class_impl(this_oop, true, CHECK); } } // Called to verify that a class can link during initialization, without // throwing a VerifyError. bool InstanceKlass::link_class_or_fail(TRAPS) { assert(is_loaded(), "must be loaded"); if (!is_linked()) { HandleMark hm(THREAD); instanceKlassHandle this_oop(THREAD, this); link_class_impl(this_oop, false, CHECK_false); } return is_linked(); } bool InstanceKlass::link_class_impl( instanceKlassHandle this_oop, bool throw_verifyerror, TRAPS) { // check for error state if (this_oop->is_in_error_state()) { ResourceMark rm(THREAD); THROW_MSG_(vmSymbols::java_lang_NoClassDefFoundError(), this_oop->external_name(), false); } // return if already verified if (this_oop->is_linked()) { return true; } // Timing // timer handles recursion assert(THREAD->is_Java_thread(), "non-JavaThread in link_class_impl"); JavaThread* jt = (JavaThread*)THREAD; // link super class before linking this class instanceKlassHandle super(THREAD, this_oop->super()); if (super.not_null()) { if (super->is_interface()) { // check if super class is an interface ResourceMark rm(THREAD); Exceptions::fthrow( THREAD_AND_LOCATION, vmSymbols::java_lang_IncompatibleClassChangeError(), "class %s has interface %s as super class", this_oop->external_name(), super->external_name() ); return false; } link_class_impl(super, throw_verifyerror, CHECK_false); } // link all interfaces implemented by this class before linking this class Array* interfaces = this_oop->local_interfaces(); int num_interfaces = interfaces->length(); for (int index = 0; index < num_interfaces; index++) { HandleMark hm(THREAD); instanceKlassHandle ih(THREAD, interfaces->at(index)); link_class_impl(ih, throw_verifyerror, CHECK_false); } // in case the class is linked in the process of linking its superclasses if (this_oop->is_linked()) { return true; } // trace only the link time for this klass that includes // the verification time PerfClassTraceTime vmtimer(ClassLoader::perf_class_link_time(), ClassLoader::perf_class_link_selftime(), ClassLoader::perf_classes_linked(), jt->get_thread_stat()->perf_recursion_counts_addr(), jt->get_thread_stat()->perf_timers_addr(), PerfClassTraceTime::CLASS_LINK); // verification & rewriting { oop init_lock = this_oop->init_lock(); ObjectLocker ol(init_lock, THREAD, init_lock != NULL); // rewritten will have been set if loader constraint error found // on an earlier link attempt // don't verify or rewrite if already rewritten if (!this_oop->is_linked()) { if (!this_oop->is_rewritten()) { { // Timer includes any side effects of class verification (resolution, // etc), but not recursive entry into verify_code(). PerfClassTraceTime timer(ClassLoader::perf_class_verify_time(), ClassLoader::perf_class_verify_selftime(), ClassLoader::perf_classes_verified(), jt->get_thread_stat()->perf_recursion_counts_addr(), jt->get_thread_stat()->perf_timers_addr(), PerfClassTraceTime::CLASS_VERIFY); bool verify_ok = verify_code(this_oop, throw_verifyerror, THREAD); if (!verify_ok) { return false; } } // Just in case a side-effect of verify linked this class already // (which can sometimes happen since the verifier loads classes // using custom class loaders, which are free to initialize things) if (this_oop->is_linked()) { return true; } // also sets rewritten this_oop->rewrite_class(CHECK_false); } // relocate jsrs and link methods after they are all rewritten this_oop->link_methods(CHECK_false); // Initialize the vtable and interface table after // methods have been rewritten since rewrite may // fabricate new Method*s. // also does loader constraint checking if (!this_oop()->is_shared()) { ResourceMark rm(THREAD); this_oop->vtable()->initialize_vtable(true, CHECK_false); this_oop->itable()->initialize_itable(true, CHECK_false); } #ifdef ASSERT else { ResourceMark rm(THREAD); this_oop->vtable()->verify(tty, true); // In case itable verification is ever added. // this_oop->itable()->verify(tty, true); } #endif this_oop->set_init_state(linked); if (JvmtiExport::should_post_class_prepare()) { Thread *thread = THREAD; assert(thread->is_Java_thread(), "thread->is_Java_thread()"); JvmtiExport::post_class_prepare((JavaThread *) thread, this_oop()); } } } return true; } // Rewrite the byte codes of all of the methods of a class. // The rewriter must be called exactly once. Rewriting must happen after // verification but before the first method of the class is executed. void InstanceKlass::rewrite_class(TRAPS) { assert(is_loaded(), "must be loaded"); instanceKlassHandle this_oop(THREAD, this); if (this_oop->is_rewritten()) { assert(this_oop()->is_shared(), "rewriting an unshared class?"); return; } Rewriter::rewrite(this_oop, CHECK); this_oop->set_rewritten(); } // Now relocate and link method entry points after class is rewritten. // This is outside is_rewritten flag. In case of an exception, it can be // executed more than once. void InstanceKlass::link_methods(TRAPS) { int len = methods()->length(); for (int i = len-1; i >= 0; i--) { methodHandle m(THREAD, methods()->at(i)); // Set up method entry points for compiler and interpreter . m->link_method(m, CHECK); // This is for JVMTI and unrelated to relocator but the last thing we do #ifdef ASSERT if (StressMethodComparator) { ResourceMark rm(THREAD); static int nmc = 0; for (int j = i; j >= 0 && j >= i-4; j--) { if ((++nmc % 1000) == 0) tty->print_cr("Have run MethodComparator %d times...", nmc); bool z = MethodComparator::methods_EMCP(m(), methods()->at(j)); if (j == i && !z) { tty->print("MethodComparator FAIL: "); m->print(); m->print_codes(); assert(z, "method must compare equal to itself"); } } } #endif //ASSERT } } void InstanceKlass::initialize_impl(instanceKlassHandle this_oop, TRAPS) { // Make sure klass is linked (verified) before initialization // A class could already be verified, since it has been reflected upon. this_oop->link_class(CHECK); DTRACE_CLASSINIT_PROBE(required, InstanceKlass::cast(this_oop()), -1); bool wait = false; // refer to the JVM book page 47 for description of steps // Step 1 { oop init_lock = this_oop->init_lock(); ObjectLocker ol(init_lock, THREAD, init_lock != NULL); Thread *self = THREAD; // it's passed the current thread // Step 2 // If we were to use wait() instead of waitInterruptibly() then // we might end up throwing IE from link/symbol resolution sites // that aren't expected to throw. This would wreak havoc. See 6320309. while(this_oop->is_being_initialized() && !this_oop->is_reentrant_initialization(self)) { wait = true; ol.waitUninterruptibly(CHECK); } // Step 3 if (this_oop->is_being_initialized() && this_oop->is_reentrant_initialization(self)) { DTRACE_CLASSINIT_PROBE_WAIT(recursive, InstanceKlass::cast(this_oop()), -1,wait); return; } // Step 4 if (this_oop->is_initialized()) { DTRACE_CLASSINIT_PROBE_WAIT(concurrent, InstanceKlass::cast(this_oop()), -1,wait); return; } // Step 5 if (this_oop->is_in_error_state()) { DTRACE_CLASSINIT_PROBE_WAIT(erroneous, InstanceKlass::cast(this_oop()), -1,wait); ResourceMark rm(THREAD); const char* desc = "Could not initialize class "; const char* className = this_oop->external_name(); size_t msglen = strlen(desc) + strlen(className) + 1; char* message = NEW_RESOURCE_ARRAY(char, msglen); if (NULL == message) { // Out of memory: can't create detailed error message THROW_MSG(vmSymbols::java_lang_NoClassDefFoundError(), className); } else { jio_snprintf(message, msglen, "%s%s", desc, className); THROW_MSG(vmSymbols::java_lang_NoClassDefFoundError(), message); } } // Step 6 this_oop->set_init_state(being_initialized); this_oop->set_init_thread(self); } // Step 7 Klass* super_klass = this_oop->super(); if (super_klass != NULL && !this_oop->is_interface() && super_klass->should_be_initialized()) { super_klass->initialize(THREAD); if (HAS_PENDING_EXCEPTION) { Handle e(THREAD, PENDING_EXCEPTION); CLEAR_PENDING_EXCEPTION; { EXCEPTION_MARK; this_oop->set_initialization_state_and_notify(initialization_error, THREAD); // Locks object, set state, and notify all waiting threads CLEAR_PENDING_EXCEPTION; // ignore any exception thrown, superclass initialization error is thrown below } DTRACE_CLASSINIT_PROBE_WAIT(super__failed, InstanceKlass::cast(this_oop()), -1,wait); THROW_OOP(e()); } } if (this_oop->has_default_methods()) { // Step 7.5: initialize any interfaces which have default methods for (int i = 0; i < this_oop->local_interfaces()->length(); ++i) { Klass* iface = this_oop->local_interfaces()->at(i); InstanceKlass* ik = InstanceKlass::cast(iface); if (ik->has_default_methods() && ik->should_be_initialized()) { ik->initialize(THREAD); if (HAS_PENDING_EXCEPTION) { Handle e(THREAD, PENDING_EXCEPTION); CLEAR_PENDING_EXCEPTION; { EXCEPTION_MARK; // Locks object, set state, and notify all waiting threads this_oop->set_initialization_state_and_notify( initialization_error, THREAD); // ignore any exception thrown, superclass initialization error is // thrown below CLEAR_PENDING_EXCEPTION; } DTRACE_CLASSINIT_PROBE_WAIT( super__failed, InstanceKlass::cast(this_oop()), -1, wait); THROW_OOP(e()); } } } } // Step 8 { assert(THREAD->is_Java_thread(), "non-JavaThread in initialize_impl"); JavaThread* jt = (JavaThread*)THREAD; DTRACE_CLASSINIT_PROBE_WAIT(clinit, InstanceKlass::cast(this_oop()), -1,wait); // Timer includes any side effects of class initialization (resolution, // etc), but not recursive entry into call_class_initializer(). PerfClassTraceTime timer(ClassLoader::perf_class_init_time(), ClassLoader::perf_class_init_selftime(), ClassLoader::perf_classes_inited(), jt->get_thread_stat()->perf_recursion_counts_addr(), jt->get_thread_stat()->perf_timers_addr(), PerfClassTraceTime::CLASS_CLINIT); this_oop->call_class_initializer(THREAD); } // Step 9 if (!HAS_PENDING_EXCEPTION) { this_oop->set_initialization_state_and_notify(fully_initialized, CHECK); { ResourceMark rm(THREAD); debug_only(this_oop->vtable()->verify(tty, true);) } } else { // Step 10 and 11 Handle e(THREAD, PENDING_EXCEPTION); CLEAR_PENDING_EXCEPTION; { EXCEPTION_MARK; this_oop->set_initialization_state_and_notify(initialization_error, THREAD); CLEAR_PENDING_EXCEPTION; // ignore any exception thrown, class initialization error is thrown below } DTRACE_CLASSINIT_PROBE_WAIT(error, InstanceKlass::cast(this_oop()), -1,wait); if (e->is_a(SystemDictionary::Error_klass())) { THROW_OOP(e()); } else { JavaCallArguments args(e); THROW_ARG(vmSymbols::java_lang_ExceptionInInitializerError(), vmSymbols::throwable_void_signature(), &args); } } DTRACE_CLASSINIT_PROBE_WAIT(end, InstanceKlass::cast(this_oop()), -1,wait); } // Note: implementation moved to static method to expose the this pointer. void InstanceKlass::set_initialization_state_and_notify(ClassState state, TRAPS) { instanceKlassHandle kh(THREAD, this); set_initialization_state_and_notify_impl(kh, state, CHECK); } void InstanceKlass::set_initialization_state_and_notify_impl(instanceKlassHandle this_oop, ClassState state, TRAPS) { oop init_lock = this_oop->init_lock(); ObjectLocker ol(init_lock, THREAD, init_lock != NULL); this_oop->set_init_state(state); this_oop->fence_and_clear_init_lock(); ol.notify_all(CHECK); } // The embedded _implementor field can only record one implementor. // When there are more than one implementors, the _implementor field // is set to the interface Klass* itself. Following are the possible // values for the _implementor field: // NULL - no implementor // implementor Klass* - one implementor // self - more than one implementor // // The _implementor field only exists for interfaces. void InstanceKlass::add_implementor(Klass* k) { assert(Compile_lock->owned_by_self(), ""); assert(is_interface(), "not interface"); // Filter out my subinterfaces. // (Note: Interfaces are never on the subklass list.) if (InstanceKlass::cast(k)->is_interface()) return; // Filter out subclasses whose supers already implement me. // (Note: CHA must walk subclasses of direct implementors // in order to locate indirect implementors.) Klass* sk = InstanceKlass::cast(k)->super(); if (sk != NULL && InstanceKlass::cast(sk)->implements_interface(this)) // We only need to check one immediate superclass, since the // implements_interface query looks at transitive_interfaces. // Any supers of the super have the same (or fewer) transitive_interfaces. return; Klass* ik = implementor(); if (ik == NULL) { set_implementor(k); } else if (ik != this) { // There is already an implementor. Use itself as an indicator of // more than one implementors. set_implementor(this); } // The implementor also implements the transitive_interfaces for (int index = 0; index < local_interfaces()->length(); index++) { InstanceKlass::cast(local_interfaces()->at(index))->add_implementor(k); } } void InstanceKlass::init_implementor() { if (is_interface()) { set_implementor(NULL); } } void InstanceKlass::process_interfaces(Thread *thread) { // link this class into the implementors list of every interface it implements Klass* this_as_klass_oop = this; for (int i = local_interfaces()->length() - 1; i >= 0; i--) { assert(local_interfaces()->at(i)->is_klass(), "must be a klass"); InstanceKlass* interf = InstanceKlass::cast(local_interfaces()->at(i)); assert(interf->is_interface(), "expected interface"); interf->add_implementor(this_as_klass_oop); } } bool InstanceKlass::can_be_primary_super_slow() const { if (is_interface()) return false; else return Klass::can_be_primary_super_slow(); } GrowableArray* InstanceKlass::compute_secondary_supers(int num_extra_slots) { // The secondaries are the implemented interfaces. InstanceKlass* ik = InstanceKlass::cast(this); Array* interfaces = ik->transitive_interfaces(); int num_secondaries = num_extra_slots + interfaces->length(); if (num_secondaries == 0) { // Must share this for correct bootstrapping! set_secondary_supers(Universe::the_empty_klass_array()); return NULL; } else if (num_extra_slots == 0) { // The secondary super list is exactly the same as the transitive interfaces. // Redefine classes has to be careful not to delete this! set_secondary_supers(interfaces); return NULL; } else { // Copy transitive interfaces to a temporary growable array to be constructed // into the secondary super list with extra slots. GrowableArray* secondaries = new GrowableArray(interfaces->length()); for (int i = 0; i < interfaces->length(); i++) { secondaries->push(interfaces->at(i)); } return secondaries; } } bool InstanceKlass::compute_is_subtype_of(Klass* k) { if (k->is_interface()) { return implements_interface(k); } else { return Klass::compute_is_subtype_of(k); } } bool InstanceKlass::implements_interface(Klass* k) const { if (this == k) return true; assert(k->is_interface(), "should be an interface class"); for (int i = 0; i < transitive_interfaces()->length(); i++) { if (transitive_interfaces()->at(i) == k) { return true; } } return false; } bool InstanceKlass::is_same_or_direct_interface(Klass *k) const { // Verify direct super interface if (this == k) return true; assert(k->is_interface(), "should be an interface class"); for (int i = 0; i < local_interfaces()->length(); i++) { if (local_interfaces()->at(i) == k) { return true; } } return false; } objArrayOop InstanceKlass::allocate_objArray(int n, int length, TRAPS) { if (length < 0) THROW_0(vmSymbols::java_lang_NegativeArraySizeException()); if (length > arrayOopDesc::max_array_length(T_OBJECT)) { report_java_out_of_memory("Requested array size exceeds VM limit"); JvmtiExport::post_array_size_exhausted(); THROW_OOP_0(Universe::out_of_memory_error_array_size()); } int size = objArrayOopDesc::object_size(length); Klass* ak = array_klass(n, CHECK_NULL); KlassHandle h_ak (THREAD, ak); objArrayOop o = (objArrayOop)CollectedHeap::array_allocate(h_ak, size, length, CHECK_NULL); return o; } instanceOop InstanceKlass::register_finalizer(instanceOop i, TRAPS) { if (TraceFinalizerRegistration) { tty->print("Registered "); i->print_value_on(tty); tty->print_cr(" (" INTPTR_FORMAT ") as finalizable", (address)i); } instanceHandle h_i(THREAD, i); // Pass the handle as argument, JavaCalls::call expects oop as jobjects JavaValue result(T_VOID); JavaCallArguments args(h_i); methodHandle mh (THREAD, Universe::finalizer_register_method()); JavaCalls::call(&result, mh, &args, CHECK_NULL); return h_i(); } instanceOop InstanceKlass::allocate_instance(TRAPS) { bool has_finalizer_flag = has_finalizer(); // Query before possible GC int size = size_helper(); // Query before forming handle. KlassHandle h_k(THREAD, this); instanceOop i; i = (instanceOop)CollectedHeap::obj_allocate(h_k, size, CHECK_NULL); if (has_finalizer_flag && !RegisterFinalizersAtInit) { i = register_finalizer(i, CHECK_NULL); } return i; } void InstanceKlass::check_valid_for_instantiation(bool throwError, TRAPS) { if (is_interface() || is_abstract()) { ResourceMark rm(THREAD); THROW_MSG(throwError ? vmSymbols::java_lang_InstantiationError() : vmSymbols::java_lang_InstantiationException(), external_name()); } if (this == SystemDictionary::Class_klass()) { ResourceMark rm(THREAD); THROW_MSG(throwError ? vmSymbols::java_lang_IllegalAccessError() : vmSymbols::java_lang_IllegalAccessException(), external_name()); } } Klass* InstanceKlass::array_klass_impl(bool or_null, int n, TRAPS) { instanceKlassHandle this_oop(THREAD, this); return array_klass_impl(this_oop, or_null, n, THREAD); } Klass* InstanceKlass::array_klass_impl(instanceKlassHandle this_oop, bool or_null, int n, TRAPS) { if (this_oop->array_klasses() == NULL) { if (or_null) return NULL; ResourceMark rm; JavaThread *jt = (JavaThread *)THREAD; { // Atomic creation of array_klasses MutexLocker mc(Compile_lock, THREAD); // for vtables MutexLocker ma(MultiArray_lock, THREAD); // Check if update has already taken place if (this_oop->array_klasses() == NULL) { Klass* k = ObjArrayKlass::allocate_objArray_klass(this_oop->class_loader_data(), 1, this_oop, CHECK_NULL); this_oop->set_array_klasses(k); } } } // _this will always be set at this point ObjArrayKlass* oak = (ObjArrayKlass*)this_oop->array_klasses(); if (or_null) { return oak->array_klass_or_null(n); } return oak->array_klass(n, CHECK_NULL); } Klass* InstanceKlass::array_klass_impl(bool or_null, TRAPS) { return array_klass_impl(or_null, 1, THREAD); } void InstanceKlass::call_class_initializer(TRAPS) { instanceKlassHandle ik (THREAD, this); call_class_initializer_impl(ik, THREAD); } static int call_class_initializer_impl_counter = 0; // for debugging Method* InstanceKlass::class_initializer() { Method* clinit = find_method( vmSymbols::class_initializer_name(), vmSymbols::void_method_signature()); if (clinit != NULL && clinit->has_valid_initializer_flags()) { return clinit; } return NULL; } void InstanceKlass::call_class_initializer_impl(instanceKlassHandle this_oop, TRAPS) { if (ReplayCompiles && (ReplaySuppressInitializers == 1 || ReplaySuppressInitializers >= 2 && this_oop->class_loader() != NULL)) { // Hide the existence of the initializer for the purpose of replaying the compile return; } methodHandle h_method(THREAD, this_oop->class_initializer()); assert(!this_oop->is_initialized(), "we cannot initialize twice"); if (TraceClassInitialization) { tty->print("%d Initializing ", call_class_initializer_impl_counter++); this_oop->name()->print_value(); tty->print_cr("%s (" INTPTR_FORMAT ")", h_method() == NULL ? "(no method)" : "", (address)this_oop()); } if (h_method() != NULL) { JavaCallArguments args; // No arguments JavaValue result(T_VOID); JavaCalls::call(&result, h_method, &args, CHECK); // Static call (no args) } } void InstanceKlass::mask_for(methodHandle method, int bci, InterpreterOopMap* entry_for) { // Dirty read, then double-check under a lock. if (_oop_map_cache == NULL) { // Otherwise, allocate a new one. MutexLocker x(OopMapCacheAlloc_lock); // First time use. Allocate a cache in C heap if (_oop_map_cache == NULL) { // Release stores from OopMapCache constructor before assignment // to _oop_map_cache. C++ compilers on ppc do not emit the // required memory barrier only because of the volatile // qualifier of _oop_map_cache. OrderAccess::release_store_ptr(&_oop_map_cache, new OopMapCache()); } } // _oop_map_cache is constant after init; lookup below does is own locking. _oop_map_cache->lookup(method, bci, entry_for); } bool InstanceKlass::find_local_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const { for (JavaFieldStream fs(this); !fs.done(); fs.next()) { Symbol* f_name = fs.name(); Symbol* f_sig = fs.signature(); if (f_name == name && f_sig == sig) { fd->reinitialize(const_cast(this), fs.index()); return true; } } return false; } Klass* InstanceKlass::find_interface_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const { const int n = local_interfaces()->length(); for (int i = 0; i < n; i++) { Klass* intf1 = local_interfaces()->at(i); assert(intf1->is_interface(), "just checking type"); // search for field in current interface if (InstanceKlass::cast(intf1)->find_local_field(name, sig, fd)) { assert(fd->is_static(), "interface field must be static"); return intf1; } // search for field in direct superinterfaces Klass* intf2 = InstanceKlass::cast(intf1)->find_interface_field(name, sig, fd); if (intf2 != NULL) return intf2; } // otherwise field lookup fails return NULL; } Klass* InstanceKlass::find_field(Symbol* name, Symbol* sig, fieldDescriptor* fd) const { // search order according to newest JVM spec (5.4.3.2, p.167). // 1) search for field in current klass if (find_local_field(name, sig, fd)) { return const_cast(this); } // 2) search for field recursively in direct superinterfaces { Klass* intf = find_interface_field(name, sig, fd); if (intf != NULL) return intf; } // 3) apply field lookup recursively if superclass exists { Klass* supr = super(); if (supr != NULL) return InstanceKlass::cast(supr)->find_field(name, sig, fd); } // 4) otherwise field lookup fails return NULL; } Klass* InstanceKlass::find_field(Symbol* name, Symbol* sig, bool is_static, fieldDescriptor* fd) const { // search order according to newest JVM spec (5.4.3.2, p.167). // 1) search for field in current klass if (find_local_field(name, sig, fd)) { if (fd->is_static() == is_static) return const_cast(this); } // 2) search for field recursively in direct superinterfaces if (is_static) { Klass* intf = find_interface_field(name, sig, fd); if (intf != NULL) return intf; } // 3) apply field lookup recursively if superclass exists { Klass* supr = super(); if (supr != NULL) return InstanceKlass::cast(supr)->find_field(name, sig, is_static, fd); } // 4) otherwise field lookup fails return NULL; } bool InstanceKlass::find_local_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const { for (JavaFieldStream fs(this); !fs.done(); fs.next()) { if (fs.offset() == offset) { fd->reinitialize(const_cast(this), fs.index()); if (fd->is_static() == is_static) return true; } } return false; } bool InstanceKlass::find_field_from_offset(int offset, bool is_static, fieldDescriptor* fd) const { Klass* klass = const_cast(this); while (klass != NULL) { if (InstanceKlass::cast(klass)->find_local_field_from_offset(offset, is_static, fd)) { return true; } klass = klass->super(); } return false; } void InstanceKlass::methods_do(void f(Method* method)) { int len = methods()->length(); for (int index = 0; index < len; index++) { Method* m = methods()->at(index); assert(m->is_method(), "must be method"); f(m); } } void InstanceKlass::do_local_static_fields(FieldClosure* cl) { for (JavaFieldStream fs(this); !fs.done(); fs.next()) { if (fs.access_flags().is_static()) { fieldDescriptor& fd = fs.field_descriptor(); cl->do_field(&fd); } } } void InstanceKlass::do_local_static_fields(void f(fieldDescriptor*, Handle, TRAPS), Handle mirror, TRAPS) { instanceKlassHandle h_this(THREAD, this); do_local_static_fields_impl(h_this, f, mirror, CHECK); } void InstanceKlass::do_local_static_fields_impl(instanceKlassHandle this_k, void f(fieldDescriptor* fd, Handle mirror, TRAPS), Handle mirror, TRAPS) { for (JavaFieldStream fs(this_k()); !fs.done(); fs.next()) { if (fs.access_flags().is_static()) { fieldDescriptor& fd = fs.field_descriptor(); f(&fd, mirror, CHECK); } } } static int compare_fields_by_offset(int* a, int* b) { return a[0] - b[0]; } void InstanceKlass::do_nonstatic_fields(FieldClosure* cl) { InstanceKlass* super = superklass(); if (super != NULL) { super->do_nonstatic_fields(cl); } fieldDescriptor fd; int length = java_fields_count(); // In DebugInfo nonstatic fields are sorted by offset. int* fields_sorted = NEW_C_HEAP_ARRAY(int, 2*(length+1), mtClass); int j = 0; for (int i = 0; i < length; i += 1) { fd.reinitialize(this, i); if (!fd.is_static()) { fields_sorted[j + 0] = fd.offset(); fields_sorted[j + 1] = i; j += 2; } } if (j > 0) { length = j; // _sort_Fn is defined in growableArray.hpp. qsort(fields_sorted, length/2, 2*sizeof(int), (_sort_Fn)compare_fields_by_offset); for (int i = 0; i < length; i += 2) { fd.reinitialize(this, fields_sorted[i + 1]); assert(!fd.is_static() && fd.offset() == fields_sorted[i], "only nonstatic fields"); cl->do_field(&fd); } } FREE_C_HEAP_ARRAY(int, fields_sorted, mtClass); } void InstanceKlass::array_klasses_do(void f(Klass* k, TRAPS), TRAPS) { if (array_klasses() != NULL) ArrayKlass::cast(array_klasses())->array_klasses_do(f, THREAD); } void InstanceKlass::array_klasses_do(void f(Klass* k)) { if (array_klasses() != NULL) ArrayKlass::cast(array_klasses())->array_klasses_do(f); } #ifdef ASSERT static int linear_search(Array* methods, Symbol* name, Symbol* signature) { int len = methods->length(); for (int index = 0; index < len; index++) { Method* m = methods->at(index); assert(m->is_method(), "must be method"); if (m->signature() == signature && m->name() == name) { return index; } } return -1; } #endif static int binary_search(Array* methods, Symbol* name) { int len = methods->length(); // methods are sorted, so do binary search int l = 0; int h = len - 1; while (l <= h) { int mid = (l + h) >> 1; Method* m = methods->at(mid); assert(m->is_method(), "must be method"); int res = m->name()->fast_compare(name); if (res == 0) { return mid; } else if (res < 0) { l = mid + 1; } else { h = mid - 1; } } return -1; } // find_method looks up the name/signature in the local methods array Method* InstanceKlass::find_method(Symbol* name, Symbol* signature) const { return find_method_impl(name, signature, false); } Method* InstanceKlass::find_method_impl(Symbol* name, Symbol* signature, bool skipping_overpass) const { return InstanceKlass::find_method_impl(methods(), name, signature, skipping_overpass); } // find_instance_method looks up the name/signature in the local methods array // and skips over static methods Method* InstanceKlass::find_instance_method( Array* methods, Symbol* name, Symbol* signature) { Method* meth = InstanceKlass::find_method(methods, name, signature); if (meth != NULL && meth->is_static()) { meth = NULL; } return meth; } // find_method looks up the name/signature in the local methods array Method* InstanceKlass::find_method( Array* methods, Symbol* name, Symbol* signature) { return InstanceKlass::find_method_impl(methods, name, signature, false); } Method* InstanceKlass::find_method_impl( Array* methods, Symbol* name, Symbol* signature, bool skipping_overpass) { int hit = find_method_index(methods, name, signature, skipping_overpass); return hit >= 0 ? methods->at(hit): NULL; } // Used directly for default_methods to find the index into the // default_vtable_indices, and indirectly by find_method // find_method_index looks in the local methods array to return the index // of the matching name/signature. If, overpass methods are being ignored, // the search continues to find a potential non-overpass match. This capability // is important during method resolution to prefer a static method, for example, // over an overpass method. int InstanceKlass::find_method_index( Array* methods, Symbol* name, Symbol* signature, bool skipping_overpass) { int hit = binary_search(methods, name); if (hit != -1) { Method* m = methods->at(hit); // Do linear search to find matching signature. First, quick check // for common case, ignoring overpasses if requested. if ((m->signature() == signature) && (!skipping_overpass || !m->is_overpass())) return hit; // search downwards through overloaded methods int i; for (i = hit - 1; i >= 0; --i) { Method* m = methods->at(i); assert(m->is_method(), "must be method"); if (m->name() != name) break; if ((m->signature() == signature) && (!skipping_overpass || !m->is_overpass())) return i; } // search upwards for (i = hit + 1; i < methods->length(); ++i) { Method* m = methods->at(i); assert(m->is_method(), "must be method"); if (m->name() != name) break; if ((m->signature() == signature) && (!skipping_overpass || !m->is_overpass())) return i; } // not found #ifdef ASSERT int index = skipping_overpass ? -1 : linear_search(methods, name, signature); assert(index == -1, err_msg("binary search should have found entry %d", index)); #endif } return -1; } int InstanceKlass::find_method_by_name(Symbol* name, int* end) { return find_method_by_name(methods(), name, end); } int InstanceKlass::find_method_by_name( Array* methods, Symbol* name, int* end_ptr) { assert(end_ptr != NULL, "just checking"); int start = binary_search(methods, name); int end = start + 1; if (start != -1) { while (start - 1 >= 0 && (methods->at(start - 1))->name() == name) --start; while (end < methods->length() && (methods->at(end))->name() == name) ++end; *end_ptr = end; return start; } return -1; } // uncached_lookup_method searches both the local class methods array and all // superclasses methods arrays, skipping any overpass methods in superclasses. Method* InstanceKlass::uncached_lookup_method(Symbol* name, Symbol* signature, MethodLookupMode mode) const { MethodLookupMode lookup_mode = mode; Klass* klass = const_cast(this); while (klass != NULL) { Method* method = InstanceKlass::cast(klass)->find_method_impl(name, signature, (lookup_mode == skip_overpass)); if (method != NULL) { return method; } klass = InstanceKlass::cast(klass)->super(); lookup_mode = skip_overpass; // Always ignore overpass methods in superclasses } return NULL; } // lookup a method in the default methods list then in all transitive interfaces // Do NOT return private or static methods Method* InstanceKlass::lookup_method_in_ordered_interfaces(Symbol* name, Symbol* signature) const { Method* m = NULL; if (default_methods() != NULL) { m = find_method(default_methods(), name, signature); } // Look up interfaces if (m == NULL) { m = lookup_method_in_all_interfaces(name, signature, normal); } return m; } // lookup a method in all the interfaces that this class implements // Do NOT return private or static methods, new in JDK8 which are not externally visible // They should only be found in the initial InterfaceMethodRef Method* InstanceKlass::lookup_method_in_all_interfaces(Symbol* name, Symbol* signature, MethodLookupMode mode) const { Array* all_ifs = transitive_interfaces(); int num_ifs = all_ifs->length(); InstanceKlass *ik = NULL; for (int i = 0; i < num_ifs; i++) { ik = InstanceKlass::cast(all_ifs->at(i)); Method* m = ik->lookup_method(name, signature); if (m != NULL && m->is_public() && !m->is_static() && ((mode != skip_defaults) || !m->is_default_method())) { return m; } } return NULL; } /* jni_id_for_impl for jfieldIds only */ JNIid* InstanceKlass::jni_id_for_impl(instanceKlassHandle this_oop, int offset) { MutexLocker ml(JfieldIdCreation_lock); // Retry lookup after we got the lock JNIid* probe = this_oop->jni_ids() == NULL ? NULL : this_oop->jni_ids()->find(offset); if (probe == NULL) { // Slow case, allocate new static field identifier probe = new JNIid(this_oop(), offset, this_oop->jni_ids()); this_oop->set_jni_ids(probe); } return probe; } /* jni_id_for for jfieldIds only */ JNIid* InstanceKlass::jni_id_for(int offset) { JNIid* probe = jni_ids() == NULL ? NULL : jni_ids()->find(offset); if (probe == NULL) { probe = jni_id_for_impl(this, offset); } return probe; } u2 InstanceKlass::enclosing_method_data(int offset) { Array* inner_class_list = inner_classes(); if (inner_class_list == NULL) { return 0; } int length = inner_class_list->length(); if (length % inner_class_next_offset == 0) { return 0; } else { int index = length - enclosing_method_attribute_size; assert(offset < enclosing_method_attribute_size, "invalid offset"); return inner_class_list->at(index + offset); } } void InstanceKlass::set_enclosing_method_indices(u2 class_index, u2 method_index) { Array* inner_class_list = inner_classes(); assert (inner_class_list != NULL, "_inner_classes list is not set up"); int length = inner_class_list->length(); if (length % inner_class_next_offset == enclosing_method_attribute_size) { int index = length - enclosing_method_attribute_size; inner_class_list->at_put( index + enclosing_method_class_index_offset, class_index); inner_class_list->at_put( index + enclosing_method_method_index_offset, method_index); } } // Lookup or create a jmethodID. // This code is called by the VMThread and JavaThreads so the // locking has to be done very carefully to avoid deadlocks // and/or other cache consistency problems. // jmethodID InstanceKlass::get_jmethod_id(instanceKlassHandle ik_h, methodHandle method_h) { size_t idnum = (size_t)method_h->method_idnum(); jmethodID* jmeths = ik_h->methods_jmethod_ids_acquire(); size_t length = 0; jmethodID id = NULL; // We use a double-check locking idiom here because this cache is // performance sensitive. In the normal system, this cache only // transitions from NULL to non-NULL which is safe because we use // release_set_methods_jmethod_ids() to advertise the new cache. // A partially constructed cache should never be seen by a racing // thread. We also use release_store_ptr() to save a new jmethodID // in the cache so a partially constructed jmethodID should never be // seen either. Cache reads of existing jmethodIDs proceed without a // lock, but cache writes of a new jmethodID requires uniqueness and // creation of the cache itself requires no leaks so a lock is // generally acquired in those two cases. // // If the RedefineClasses() API has been used, then this cache can // grow and we'll have transitions from non-NULL to bigger non-NULL. // Cache creation requires no leaks and we require safety between all // cache accesses and freeing of the old cache so a lock is generally // acquired when the RedefineClasses() API has been used. if (jmeths != NULL) { // the cache already exists if (!ik_h->idnum_can_increment()) { // the cache can't grow so we can just get the current values get_jmethod_id_length_value(jmeths, idnum, &length, &id); } else { // cache can grow so we have to be more careful if (Threads::number_of_threads() == 0 || SafepointSynchronize::is_at_safepoint()) { // we're single threaded or at a safepoint - no locking needed get_jmethod_id_length_value(jmeths, idnum, &length, &id); } else { MutexLocker ml(JmethodIdCreation_lock); get_jmethod_id_length_value(jmeths, idnum, &length, &id); } } } // implied else: // we need to allocate a cache so default length and id values are good if (jmeths == NULL || // no cache yet length <= idnum || // cache is too short id == NULL) { // cache doesn't contain entry // This function can be called by the VMThread so we have to do all // things that might block on a safepoint before grabbing the lock. // Otherwise, we can deadlock with the VMThread or have a cache // consistency issue. These vars keep track of what we might have // to free after the lock is dropped. jmethodID to_dealloc_id = NULL; jmethodID* to_dealloc_jmeths = NULL; // may not allocate new_jmeths or use it if we allocate it jmethodID* new_jmeths = NULL; if (length <= idnum) { // allocate a new cache that might be used size_t size = MAX2(idnum+1, (size_t)ik_h->idnum_allocated_count()); new_jmeths = NEW_C_HEAP_ARRAY(jmethodID, size+1, mtClass); memset(new_jmeths, 0, (size+1)*sizeof(jmethodID)); // cache size is stored in element[0], other elements offset by one new_jmeths[0] = (jmethodID)size; } // allocate a new jmethodID that might be used jmethodID new_id = NULL; if (method_h->is_old() && !method_h->is_obsolete()) { // The method passed in is old (but not obsolete), we need to use the current version Method* current_method = ik_h->method_with_idnum((int)idnum); assert(current_method != NULL, "old and but not obsolete, so should exist"); new_id = Method::make_jmethod_id(ik_h->class_loader_data(), current_method); } else { // It is the current version of the method or an obsolete method, // use the version passed in new_id = Method::make_jmethod_id(ik_h->class_loader_data(), method_h()); } if (Threads::number_of_threads() == 0 || SafepointSynchronize::is_at_safepoint()) { // we're single threaded or at a safepoint - no locking needed id = get_jmethod_id_fetch_or_update(ik_h, idnum, new_id, new_jmeths, &to_dealloc_id, &to_dealloc_jmeths); } else { MutexLocker ml(JmethodIdCreation_lock); id = get_jmethod_id_fetch_or_update(ik_h, idnum, new_id, new_jmeths, &to_dealloc_id, &to_dealloc_jmeths); } // The lock has been dropped so we can free resources. // Free up either the old cache or the new cache if we allocated one. if (to_dealloc_jmeths != NULL) { FreeHeap(to_dealloc_jmeths); } // free up the new ID since it wasn't needed if (to_dealloc_id != NULL) { Method::destroy_jmethod_id(ik_h->class_loader_data(), to_dealloc_id); } } return id; } // Common code to fetch the jmethodID from the cache or update the // cache with the new jmethodID. This function should never do anything // that causes the caller to go to a safepoint or we can deadlock with // the VMThread or have cache consistency issues. // jmethodID InstanceKlass::get_jmethod_id_fetch_or_update( instanceKlassHandle ik_h, size_t idnum, jmethodID new_id, jmethodID* new_jmeths, jmethodID* to_dealloc_id_p, jmethodID** to_dealloc_jmeths_p) { assert(new_id != NULL, "sanity check"); assert(to_dealloc_id_p != NULL, "sanity check"); assert(to_dealloc_jmeths_p != NULL, "sanity check"); assert(Threads::number_of_threads() == 0 || SafepointSynchronize::is_at_safepoint() || JmethodIdCreation_lock->owned_by_self(), "sanity check"); // reacquire the cache - we are locked, single threaded or at a safepoint jmethodID* jmeths = ik_h->methods_jmethod_ids_acquire(); jmethodID id = NULL; size_t length = 0; if (jmeths == NULL || // no cache yet (length = (size_t)jmeths[0]) <= idnum) { // cache is too short if (jmeths != NULL) { // copy any existing entries from the old cache for (size_t index = 0; index < length; index++) { new_jmeths[index+1] = jmeths[index+1]; } *to_dealloc_jmeths_p = jmeths; // save old cache for later delete } ik_h->release_set_methods_jmethod_ids(jmeths = new_jmeths); } else { // fetch jmethodID (if any) from the existing cache id = jmeths[idnum+1]; *to_dealloc_jmeths_p = new_jmeths; // save new cache for later delete } if (id == NULL) { // No matching jmethodID in the existing cache or we have a new // cache or we just grew the cache. This cache write is done here // by the first thread to win the foot race because a jmethodID // needs to be unique once it is generally available. id = new_id; // The jmethodID cache can be read while unlocked so we have to // make sure the new jmethodID is complete before installing it // in the cache. OrderAccess::release_store_ptr(&jmeths[idnum+1], id); } else { *to_dealloc_id_p = new_id; // save new id for later delete } return id; } // Common code to get the jmethodID cache length and the jmethodID // value at index idnum if there is one. // void InstanceKlass::get_jmethod_id_length_value(jmethodID* cache, size_t idnum, size_t *length_p, jmethodID* id_p) { assert(cache != NULL, "sanity check"); assert(length_p != NULL, "sanity check"); assert(id_p != NULL, "sanity check"); // cache size is stored in element[0], other elements offset by one *length_p = (size_t)cache[0]; if (*length_p <= idnum) { // cache is too short *id_p = NULL; } else { *id_p = cache[idnum+1]; // fetch jmethodID (if any) } } // Lookup a jmethodID, NULL if not found. Do no blocking, no allocations, no handles jmethodID InstanceKlass::jmethod_id_or_null(Method* method) { size_t idnum = (size_t)method->method_idnum(); jmethodID* jmeths = methods_jmethod_ids_acquire(); size_t length; // length assigned as debugging crumb jmethodID id = NULL; if (jmeths != NULL && // If there is a cache (length = (size_t)jmeths[0]) > idnum) { // and if it is long enough, id = jmeths[idnum+1]; // Look up the id (may be NULL) } return id; } int nmethodBucket::decrement() { return Atomic::add(-1, (volatile int *)&_count); } // // Walk the list of dependent nmethods searching for nmethods which // are dependent on the changes that were passed in and mark them for // deoptimization. Returns the number of nmethods found. // int InstanceKlass::mark_dependent_nmethods(DepChange& changes) { assert_locked_or_safepoint(CodeCache_lock); int found = 0; nmethodBucket* b = _dependencies; while (b != NULL) { nmethod* nm = b->get_nmethod(); // since dependencies aren't removed until an nmethod becomes a zombie, // the dependency list may contain nmethods which aren't alive. if (b->count() > 0 && nm->is_alive() && !nm->is_marked_for_deoptimization() && nm->check_dependency_on(changes)) { if (TraceDependencies) { ResourceMark rm; tty->print_cr("Marked for deoptimization"); tty->print_cr(" context = %s", this->external_name()); changes.print(); nm->print(); nm->print_dependencies(); } nm->mark_for_deoptimization(); found++; } b = b->next(); } return found; } void InstanceKlass::clean_dependent_nmethods() { assert_locked_or_safepoint(CodeCache_lock); if (has_unloaded_dependent()) { nmethodBucket* b = _dependencies; nmethodBucket* last = NULL; while (b != NULL) { assert(b->count() >= 0, err_msg("bucket count: %d", b->count())); nmethodBucket* next = b->next(); if (b->count() == 0) { if (last == NULL) { _dependencies = next; } else { last->set_next(next); } delete b; // last stays the same. } else { last = b; } b = next; } set_has_unloaded_dependent(false); } #ifdef ASSERT else { // Verification for (nmethodBucket* b = _dependencies; b != NULL; b = b->next()) { assert(b->count() >= 0, err_msg("bucket count: %d", b->count())); assert(b->count() != 0, "empty buckets need to be cleaned"); } } #endif } // // Add an nmethodBucket to the list of dependencies for this nmethod. // It's possible that an nmethod has multiple dependencies on this klass // so a count is kept for each bucket to guarantee that creation and // deletion of dependencies is consistent. // void InstanceKlass::add_dependent_nmethod(nmethod* nm) { assert_locked_or_safepoint(CodeCache_lock); nmethodBucket* b = _dependencies; nmethodBucket* last = NULL; while (b != NULL) { if (nm == b->get_nmethod()) { b->increment(); return; } b = b->next(); } _dependencies = new nmethodBucket(nm, _dependencies); } // // Decrement count of the nmethod in the dependency list and remove // the bucket competely when the count goes to 0. This method must // find a corresponding bucket otherwise there's a bug in the // recording of dependecies. // void InstanceKlass::remove_dependent_nmethod(nmethod* nm) { assert_locked_or_safepoint(CodeCache_lock); nmethodBucket* b = _dependencies; nmethodBucket* last = NULL; while (b != NULL) { if (nm == b->get_nmethod()) { int val = b->decrement(); guarantee(val >= 0, err_msg("Underflow: %d", val)); if (val == 0) { set_has_unloaded_dependent(true); } return; } last = b; b = b->next(); } #ifdef ASSERT tty->print_cr("### %s can't find dependent nmethod:", this->external_name()); nm->print(); #endif // ASSERT ShouldNotReachHere(); } #ifndef PRODUCT void InstanceKlass::print_dependent_nmethods(bool verbose) { nmethodBucket* b = _dependencies; int idx = 0; while (b != NULL) { nmethod* nm = b->get_nmethod(); tty->print("[%d] count=%d { ", idx++, b->count()); if (!verbose) { nm->print_on(tty, "nmethod"); tty->print_cr(" } "); } else { nm->print(); nm->print_dependencies(); tty->print_cr("--- } "); } b = b->next(); } } bool InstanceKlass::is_dependent_nmethod(nmethod* nm) { nmethodBucket* b = _dependencies; while (b != NULL) { if (nm == b->get_nmethod()) { #ifdef ASSERT int count = b->count(); assert(count >= 0, err_msg("count shouldn't be negative: %d", count)); #endif return true; } b = b->next(); } return false; } #endif //PRODUCT // Garbage collection #ifdef ASSERT template void assert_is_in(T *p) { T heap_oop = oopDesc::load_heap_oop(p); if (!oopDesc::is_null(heap_oop)) { oop o = oopDesc::decode_heap_oop_not_null(heap_oop); assert(Universe::heap()->is_in(o), "should be in heap"); } } template void assert_is_in_closed_subset(T *p) { T heap_oop = oopDesc::load_heap_oop(p); if (!oopDesc::is_null(heap_oop)) { oop o = oopDesc::decode_heap_oop_not_null(heap_oop); assert(Universe::heap()->is_in_closed_subset(o), err_msg("should be in closed *p " INTPTR_FORMAT " " INTPTR_FORMAT, (address)p, (address)o)); } } template void assert_is_in_reserved(T *p) { T heap_oop = oopDesc::load_heap_oop(p); if (!oopDesc::is_null(heap_oop)) { oop o = oopDesc::decode_heap_oop_not_null(heap_oop); assert(Universe::heap()->is_in_reserved(o), "should be in reserved"); } } template void assert_nothing(T *p) {} #else template void assert_is_in(T *p) {} template void assert_is_in_closed_subset(T *p) {} template void assert_is_in_reserved(T *p) {} template void assert_nothing(T *p) {} #endif // ASSERT // // Macros that iterate over areas of oops which are specialized on type of // oop pointer either narrow or wide, depending on UseCompressedOops // // Parameters are: // T - type of oop to point to (either oop or narrowOop) // start_p - starting pointer for region to iterate over // count - number of oops or narrowOops to iterate over // do_oop - action to perform on each oop (it's arbitrary C code which // makes it more efficient to put in a macro rather than making // it a template function) // assert_fn - assert function which is template function because performance // doesn't matter when enabled. #define InstanceKlass_SPECIALIZED_OOP_ITERATE( \ T, start_p, count, do_oop, \ assert_fn) \ { \ T* p = (T*)(start_p); \ T* const end = p + (count); \ while (p < end) { \ (assert_fn)(p); \ do_oop; \ ++p; \ } \ } #define InstanceKlass_SPECIALIZED_OOP_REVERSE_ITERATE( \ T, start_p, count, do_oop, \ assert_fn) \ { \ T* const start = (T*)(start_p); \ T* p = start + (count); \ while (start < p) { \ --p; \ (assert_fn)(p); \ do_oop; \ } \ } #define InstanceKlass_SPECIALIZED_BOUNDED_OOP_ITERATE( \ T, start_p, count, low, high, \ do_oop, assert_fn) \ { \ T* const l = (T*)(low); \ T* const h = (T*)(high); \ assert(mask_bits((intptr_t)l, sizeof(T)-1) == 0 && \ mask_bits((intptr_t)h, sizeof(T)-1) == 0, \ "bounded region must be properly aligned"); \ T* p = (T*)(start_p); \ T* end = p + (count); \ if (p < l) p = l; \ if (end > h) end = h; \ while (p < end) { \ (assert_fn)(p); \ do_oop; \ ++p; \ } \ } // The following macros call specialized macros, passing either oop or // narrowOop as the specialization type. These test the UseCompressedOops // flag. #define InstanceKlass_OOP_MAP_ITERATE(obj, do_oop, assert_fn) \ { \ /* Compute oopmap block range. The common case \ is nonstatic_oop_map_size == 1. */ \ OopMapBlock* map = start_of_nonstatic_oop_maps(); \ OopMapBlock* const end_map = map + nonstatic_oop_map_count(); \ if (UseCompressedOops) { \ while (map < end_map) { \ InstanceKlass_SPECIALIZED_OOP_ITERATE(narrowOop, \ obj->obj_field_addr(map->offset()), map->count(), \ do_oop, assert_fn) \ ++map; \ } \ } else { \ while (map < end_map) { \ InstanceKlass_SPECIALIZED_OOP_ITERATE(oop, \ obj->obj_field_addr(map->offset()), map->count(), \ do_oop, assert_fn) \ ++map; \ } \ } \ } #define InstanceKlass_OOP_MAP_REVERSE_ITERATE(obj, do_oop, assert_fn) \ { \ OopMapBlock* const start_map = start_of_nonstatic_oop_maps(); \ OopMapBlock* map = start_map + nonstatic_oop_map_count(); \ if (UseCompressedOops) { \ while (start_map < map) { \ --map; \ InstanceKlass_SPECIALIZED_OOP_REVERSE_ITERATE(narrowOop, \ obj->obj_field_addr(map->offset()), map->count(), \ do_oop, assert_fn) \ } \ } else { \ while (start_map < map) { \ --map; \ InstanceKlass_SPECIALIZED_OOP_REVERSE_ITERATE(oop, \ obj->obj_field_addr(map->offset()), map->count(), \ do_oop, assert_fn) \ } \ } \ } #define InstanceKlass_BOUNDED_OOP_MAP_ITERATE(obj, low, high, do_oop, \ assert_fn) \ { \ /* Compute oopmap block range. The common case is \ nonstatic_oop_map_size == 1, so we accept the \ usually non-existent extra overhead of examining \ all the maps. */ \ OopMapBlock* map = start_of_nonstatic_oop_maps(); \ OopMapBlock* const end_map = map + nonstatic_oop_map_count(); \ if (UseCompressedOops) { \ while (map < end_map) { \ InstanceKlass_SPECIALIZED_BOUNDED_OOP_ITERATE(narrowOop, \ obj->obj_field_addr(map->offset()), map->count(), \ low, high, \ do_oop, assert_fn) \ ++map; \ } \ } else { \ while (map < end_map) { \ InstanceKlass_SPECIALIZED_BOUNDED_OOP_ITERATE(oop, \ obj->obj_field_addr(map->offset()), map->count(), \ low, high, \ do_oop, assert_fn) \ ++map; \ } \ } \ } void InstanceKlass::oop_follow_contents(oop obj) { assert(obj != NULL, "can't follow the content of NULL object"); MarkSweep::follow_klass(obj->klass()); InstanceKlass_OOP_MAP_ITERATE( \ obj, \ MarkSweep::mark_and_push(p), \ assert_is_in_closed_subset) } #if INCLUDE_ALL_GCS void InstanceKlass::oop_follow_contents(ParCompactionManager* cm, oop obj) { assert(obj != NULL, "can't follow the content of NULL object"); PSParallelCompact::follow_klass(cm, obj->klass()); // Only mark the header and let the scan of the meta-data mark // everything else. InstanceKlass_OOP_MAP_ITERATE( \ obj, \ PSParallelCompact::mark_and_push(cm, p), \ assert_is_in) } #endif // INCLUDE_ALL_GCS // closure's do_metadata() method dictates whether the given closure should be // applied to the klass ptr in the object header. #define InstanceKlass_OOP_OOP_ITERATE_DEFN(OopClosureType, nv_suffix) \ \ int InstanceKlass::oop_oop_iterate##nv_suffix(oop obj, OopClosureType* closure) { \ SpecializationStats::record_iterate_call##nv_suffix(SpecializationStats::ik);\ /* header */ \ if_do_metadata_checked(closure, nv_suffix) { \ closure->do_klass##nv_suffix(obj->klass()); \ } \ InstanceKlass_OOP_MAP_ITERATE( \ obj, \ SpecializationStats:: \ record_do_oop_call##nv_suffix(SpecializationStats::ik); \ (closure)->do_oop##nv_suffix(p), \ assert_is_in_closed_subset) \ return size_helper(); \ } #if INCLUDE_ALL_GCS #define InstanceKlass_OOP_OOP_ITERATE_BACKWARDS_DEFN(OopClosureType, nv_suffix) \ \ int InstanceKlass::oop_oop_iterate_backwards##nv_suffix(oop obj, \ OopClosureType* closure) { \ SpecializationStats::record_iterate_call##nv_suffix(SpecializationStats::ik); \ \ assert_should_ignore_metadata(closure, nv_suffix); \ \ /* instance variables */ \ InstanceKlass_OOP_MAP_REVERSE_ITERATE( \ obj, \ SpecializationStats::record_do_oop_call##nv_suffix(SpecializationStats::ik);\ (closure)->do_oop##nv_suffix(p), \ assert_is_in_closed_subset) \ return size_helper(); \ } #endif // INCLUDE_ALL_GCS #define InstanceKlass_OOP_OOP_ITERATE_DEFN_m(OopClosureType, nv_suffix) \ \ int InstanceKlass::oop_oop_iterate##nv_suffix##_m(oop obj, \ OopClosureType* closure, \ MemRegion mr) { \ SpecializationStats::record_iterate_call##nv_suffix(SpecializationStats::ik);\ if_do_metadata_checked(closure, nv_suffix) { \ if (mr.contains(obj)) { \ closure->do_klass##nv_suffix(obj->klass()); \ } \ } \ InstanceKlass_BOUNDED_OOP_MAP_ITERATE( \ obj, mr.start(), mr.end(), \ (closure)->do_oop##nv_suffix(p), \ assert_is_in_closed_subset) \ return size_helper(); \ } ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceKlass_OOP_OOP_ITERATE_DEFN) ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceKlass_OOP_OOP_ITERATE_DEFN) ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceKlass_OOP_OOP_ITERATE_DEFN_m) ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceKlass_OOP_OOP_ITERATE_DEFN_m) #if INCLUDE_ALL_GCS ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceKlass_OOP_OOP_ITERATE_BACKWARDS_DEFN) ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceKlass_OOP_OOP_ITERATE_BACKWARDS_DEFN) #endif // INCLUDE_ALL_GCS int InstanceKlass::oop_adjust_pointers(oop obj) { int size = size_helper(); InstanceKlass_OOP_MAP_ITERATE( \ obj, \ MarkSweep::adjust_pointer(p), \ assert_is_in) return size; } #if INCLUDE_ALL_GCS void InstanceKlass::oop_push_contents(PSPromotionManager* pm, oop obj) { InstanceKlass_OOP_MAP_REVERSE_ITERATE( \ obj, \ if (PSScavenge::should_scavenge(p)) { \ pm->claim_or_forward_depth(p); \ }, \ assert_nothing ) } int InstanceKlass::oop_update_pointers(ParCompactionManager* cm, oop obj) { int size = size_helper(); InstanceKlass_OOP_MAP_ITERATE( \ obj, \ PSParallelCompact::adjust_pointer(p), \ assert_is_in) return size; } #endif // INCLUDE_ALL_GCS void InstanceKlass::clean_implementors_list(BoolObjectClosure* is_alive) { assert(class_loader_data()->is_alive(is_alive), "this klass should be live"); if (is_interface()) { if (ClassUnloading) { Klass* impl = implementor(); if (impl != NULL) { if (!impl->is_loader_alive(is_alive)) { // remove this guy Klass** klass = adr_implementor(); assert(klass != NULL, "null klass"); if (klass != NULL) { *klass = NULL; } } } } } } void InstanceKlass::clean_method_data(BoolObjectClosure* is_alive) { for (int m = 0; m < methods()->length(); m++) { MethodData* mdo = methods()->at(m)->method_data(); if (mdo != NULL) { mdo->clean_method_data(is_alive); } } } static void remove_unshareable_in_class(Klass* k) { // remove klass's unshareable info k->remove_unshareable_info(); } void InstanceKlass::remove_unshareable_info() { Klass::remove_unshareable_info(); // Unlink the class if (is_linked()) { unlink_class(); } init_implementor(); constants()->remove_unshareable_info(); for (int i = 0; i < methods()->length(); i++) { Method* m = methods()->at(i); m->remove_unshareable_info(); } // do array classes also. array_klasses_do(remove_unshareable_in_class); } static void restore_unshareable_in_class(Klass* k, TRAPS) { // Array classes have null protection domain. // --> see ArrayKlass::complete_create_array_klass() k->restore_unshareable_info(ClassLoaderData::the_null_class_loader_data(), Handle(), CHECK); } void InstanceKlass::restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS) { Klass::restore_unshareable_info(loader_data, protection_domain, CHECK); instanceKlassHandle ik(THREAD, this); Array* methods = ik->methods(); int num_methods = methods->length(); for (int index2 = 0; index2 < num_methods; ++index2) { methodHandle m(THREAD, methods->at(index2)); m->restore_unshareable_info(CHECK); } if (JvmtiExport::has_redefined_a_class()) { // Reinitialize vtable because RedefineClasses may have changed some // entries in this vtable for super classes so the CDS vtable might // point to old or obsolete entries. RedefineClasses doesn't fix up // vtables in the shared system dictionary, only the main one. // It also redefines the itable too so fix that too. ResourceMark rm(THREAD); ik->vtable()->initialize_vtable(false, CHECK); ik->itable()->initialize_itable(false, CHECK); } // restore constant pool resolved references ik->constants()->restore_unshareable_info(CHECK); ik->array_klasses_do(restore_unshareable_in_class, CHECK); } // returns true IFF is_in_error_state() has been changed as a result of this call. bool InstanceKlass::check_sharing_error_state() { assert(DumpSharedSpaces, "should only be called during dumping"); bool old_state = is_in_error_state(); if (!is_in_error_state()) { bool bad = false; for (InstanceKlass* sup = java_super(); sup; sup = sup->java_super()) { if (sup->is_in_error_state()) { bad = true; break; } } if (!bad) { Array* interfaces = transitive_interfaces(); for (int i = 0; i < interfaces->length(); i++) { Klass* iface = interfaces->at(i); if (InstanceKlass::cast(iface)->is_in_error_state()) { bad = true; break; } } } if (bad) { set_in_error_state(); } } return (old_state != is_in_error_state()); } static void clear_all_breakpoints(Method* m) { m->clear_all_breakpoints(); } void InstanceKlass::notify_unload_class(InstanceKlass* ik) { // notify the debugger if (JvmtiExport::should_post_class_unload()) { JvmtiExport::post_class_unload(ik); } // notify ClassLoadingService of class unload ClassLoadingService::notify_class_unloaded(ik); } void InstanceKlass::release_C_heap_structures(InstanceKlass* ik) { // Clean up C heap ik->release_C_heap_structures(); ik->constants()->release_C_heap_structures(); } void InstanceKlass::release_C_heap_structures() { // Can't release the constant pool here because the constant pool can be // deallocated separately from the InstanceKlass for default methods and // redefine classes. // Deallocate oop map cache if (_oop_map_cache != NULL) { delete _oop_map_cache; _oop_map_cache = NULL; } // Deallocate JNI identifiers for jfieldIDs JNIid::deallocate(jni_ids()); set_jni_ids(NULL); jmethodID* jmeths = methods_jmethod_ids_acquire(); if (jmeths != (jmethodID*)NULL) { release_set_methods_jmethod_ids(NULL); FreeHeap(jmeths); } // Deallocate MemberNameTable { Mutex* lock_or_null = SafepointSynchronize::is_at_safepoint() ? NULL : MemberNameTable_lock; MutexLockerEx ml(lock_or_null, Mutex::_no_safepoint_check_flag); MemberNameTable* mnt = member_names(); if (mnt != NULL) { delete mnt; set_member_names(NULL); } } // release dependencies nmethodBucket* b = _dependencies; _dependencies = NULL; while (b != NULL) { nmethodBucket* next = b->next(); delete b; b = next; } // Deallocate breakpoint records if (breakpoints() != 0x0) { methods_do(clear_all_breakpoints); assert(breakpoints() == 0x0, "should have cleared breakpoints"); } // deallocate information about previous versions if (_previous_versions != NULL) { for (int i = _previous_versions->length() - 1; i >= 0; i--) { PreviousVersionNode * pv_node = _previous_versions->at(i); delete pv_node; } delete _previous_versions; _previous_versions = NULL; } // deallocate the cached class file if (_cached_class_file != NULL) { os::free(_cached_class_file, mtClass); _cached_class_file = NULL; } // Decrement symbol reference counts associated with the unloaded class. if (_name != NULL) _name->decrement_refcount(); // unreference array name derived from this class name (arrays of an unloaded // class can't be referenced anymore). if (_array_name != NULL) _array_name->decrement_refcount(); if (_source_debug_extension != NULL) FREE_C_HEAP_ARRAY(char, _source_debug_extension, mtClass); assert(_total_instanceKlass_count >= 1, "Sanity check"); Atomic::dec(&_total_instanceKlass_count); } void InstanceKlass::set_source_debug_extension(char* array, int length) { if (array == NULL) { _source_debug_extension = NULL; } else { // Adding one to the attribute length in order to store a null terminator // character could cause an overflow because the attribute length is // already coded with an u4 in the classfile, but in practice, it's // unlikely to happen. assert((length+1) > length, "Overflow checking"); char* sde = NEW_C_HEAP_ARRAY(char, (length + 1), mtClass); for (int i = 0; i < length; i++) { sde[i] = array[i]; } sde[length] = '\0'; _source_debug_extension = sde; } } address InstanceKlass::static_field_addr(int offset) { return (address)(offset + InstanceMirrorKlass::offset_of_static_fields() + cast_from_oop(java_mirror())); } const char* InstanceKlass::signature_name() const { int hash_len = 0; char hash_buf[40]; // If this is an anonymous class, append a hash to make the name unique if (is_anonymous()) { assert(EnableInvokeDynamic, "EnableInvokeDynamic was not set."); intptr_t hash = (java_mirror() != NULL) ? java_mirror()->identity_hash() : 0; sprintf(hash_buf, "/" UINTX_FORMAT, (uintx)hash); hash_len = (int)strlen(hash_buf); } // Get the internal name as a c string const char* src = (const char*) (name()->as_C_string()); const int src_length = (int)strlen(src); char* dest = NEW_RESOURCE_ARRAY(char, src_length + hash_len + 3); // Add L as type indicator int dest_index = 0; dest[dest_index++] = 'L'; // Add the actual class name for (int src_index = 0; src_index < src_length; ) { dest[dest_index++] = src[src_index++]; } // If we have a hash, append it for (int hash_index = 0; hash_index < hash_len; ) { dest[dest_index++] = hash_buf[hash_index++]; } // Add the semicolon and the NULL dest[dest_index++] = ';'; dest[dest_index] = '\0'; return dest; } // different verisons of is_same_class_package bool InstanceKlass::is_same_class_package(Klass* class2) { Klass* class1 = this; oop classloader1 = InstanceKlass::cast(class1)->class_loader(); Symbol* classname1 = class1->name(); if (class2->oop_is_objArray()) { class2 = ObjArrayKlass::cast(class2)->bottom_klass(); } oop classloader2; if (class2->oop_is_instance()) { classloader2 = InstanceKlass::cast(class2)->class_loader(); } else { assert(class2->oop_is_typeArray(), "should be type array"); classloader2 = NULL; } Symbol* classname2 = class2->name(); return InstanceKlass::is_same_class_package(classloader1, classname1, classloader2, classname2); } bool InstanceKlass::is_same_class_package(oop classloader2, Symbol* classname2) { Klass* class1 = this; oop classloader1 = InstanceKlass::cast(class1)->class_loader(); Symbol* classname1 = class1->name(); return InstanceKlass::is_same_class_package(classloader1, classname1, classloader2, classname2); } // return true if two classes are in the same package, classloader // and classname information is enough to determine a class's package bool InstanceKlass::is_same_class_package(oop class_loader1, Symbol* class_name1, oop class_loader2, Symbol* class_name2) { if (class_loader1 != class_loader2) { return false; } else if (class_name1 == class_name2) { return true; // skip painful bytewise comparison } else { ResourceMark rm; // The Symbol*'s are in UTF8 encoding. Since we only need to check explicitly // for ASCII characters ('/', 'L', '['), we can keep them in UTF8 encoding. // Otherwise, we just compare jbyte values between the strings. const jbyte *name1 = class_name1->base(); const jbyte *name2 = class_name2->base(); const jbyte *last_slash1 = UTF8::strrchr(name1, class_name1->utf8_length(), '/'); const jbyte *last_slash2 = UTF8::strrchr(name2, class_name2->utf8_length(), '/'); if ((last_slash1 == NULL) || (last_slash2 == NULL)) { // One of the two doesn't have a package. Only return true // if the other one also doesn't have a package. return last_slash1 == last_slash2; } else { // Skip over '['s if (*name1 == '[') { do { name1++; } while (*name1 == '['); if (*name1 != 'L') { // Something is terribly wrong. Shouldn't be here. return false; } } if (*name2 == '[') { do { name2++; } while (*name2 == '['); if (*name2 != 'L') { // Something is terribly wrong. Shouldn't be here. return false; } } // Check that package part is identical int length1 = last_slash1 - name1; int length2 = last_slash2 - name2; return UTF8::equal(name1, length1, name2, length2); } } } // Returns true iff super_method can be overridden by a method in targetclassname // See JSL 3rd edition 8.4.6.1 // Assumes name-signature match // "this" is InstanceKlass of super_method which must exist // note that the InstanceKlass of the method in the targetclassname has not always been created yet bool InstanceKlass::is_override(methodHandle super_method, Handle targetclassloader, Symbol* targetclassname, TRAPS) { // Private methods can not be overridden if (super_method->is_private()) { return false; } // If super method is accessible, then override if ((super_method->is_protected()) || (super_method->is_public())) { return true; } // Package-private methods are not inherited outside of package assert(super_method->is_package_private(), "must be package private"); return(is_same_class_package(targetclassloader(), targetclassname)); } /* defined for now in jvm.cpp, for historical reasons *-- Klass* InstanceKlass::compute_enclosing_class_impl(instanceKlassHandle self, Symbol*& simple_name_result, TRAPS) { ... } */ // tell if two classes have the same enclosing class (at package level) bool InstanceKlass::is_same_package_member_impl(instanceKlassHandle class1, Klass* class2_oop, TRAPS) { if (class2_oop == class1()) return true; if (!class2_oop->oop_is_instance()) return false; instanceKlassHandle class2(THREAD, class2_oop); // must be in same package before we try anything else if (!class1->is_same_class_package(class2->class_loader(), class2->name())) return false; // As long as there is an outer1.getEnclosingClass, // shift the search outward. instanceKlassHandle outer1 = class1; for (;;) { // As we walk along, look for equalities between outer1 and class2. // Eventually, the walks will terminate as outer1 stops // at the top-level class around the original class. bool ignore_inner_is_member; Klass* next = outer1->compute_enclosing_class(&ignore_inner_is_member, CHECK_false); if (next == NULL) break; if (next == class2()) return true; outer1 = instanceKlassHandle(THREAD, next); } // Now do the same for class2. instanceKlassHandle outer2 = class2; for (;;) { bool ignore_inner_is_member; Klass* next = outer2->compute_enclosing_class(&ignore_inner_is_member, CHECK_false); if (next == NULL) break; // Might as well check the new outer against all available values. if (next == class1()) return true; if (next == outer1()) return true; outer2 = instanceKlassHandle(THREAD, next); } // If by this point we have not found an equality between the // two classes, we know they are in separate package members. return false; } jint InstanceKlass::compute_modifier_flags(TRAPS) const { jint access = access_flags().as_int(); // But check if it happens to be member class. instanceKlassHandle ik(THREAD, this); InnerClassesIterator iter(ik); for (; !iter.done(); iter.next()) { int ioff = iter.inner_class_info_index(); // Inner class attribute can be zero, skip it. // Strange but true: JVM spec. allows null inner class refs. if (ioff == 0) continue; // only look at classes that are already loaded // since we are looking for the flags for our self. Symbol* inner_name = ik->constants()->klass_name_at(ioff); if ((ik->name() == inner_name)) { // This is really a member class. access = iter.inner_access_flags(); break; } } // Remember to strip ACC_SUPER bit return (access & (~JVM_ACC_SUPER)) & JVM_ACC_WRITTEN_FLAGS; } jint InstanceKlass::jvmti_class_status() const { jint result = 0; if (is_linked()) { result |= JVMTI_CLASS_STATUS_VERIFIED | JVMTI_CLASS_STATUS_PREPARED; } if (is_initialized()) { assert(is_linked(), "Class status is not consistent"); result |= JVMTI_CLASS_STATUS_INITIALIZED; } if (is_in_error_state()) { result |= JVMTI_CLASS_STATUS_ERROR; } return result; } Method* InstanceKlass::method_at_itable(Klass* holder, int index, TRAPS) { itableOffsetEntry* ioe = (itableOffsetEntry*)start_of_itable(); int method_table_offset_in_words = ioe->offset()/wordSize; int nof_interfaces = (method_table_offset_in_words - itable_offset_in_words()) / itableOffsetEntry::size(); for (int cnt = 0 ; ; cnt ++, ioe ++) { // If the interface isn't implemented by the receiver class, // the VM should throw IncompatibleClassChangeError. if (cnt >= nof_interfaces) { THROW_NULL(vmSymbols::java_lang_IncompatibleClassChangeError()); } Klass* ik = ioe->interface_klass(); if (ik == holder) break; } itableMethodEntry* ime = ioe->first_method_entry(this); Method* m = ime[index].method(); if (m == NULL) { THROW_NULL(vmSymbols::java_lang_AbstractMethodError()); } return m; } #if INCLUDE_JVMTI // update default_methods for redefineclasses for methods that are // not yet in the vtable due to concurrent subclass define and superinterface // redefinition // Note: those in the vtable, should have been updated via adjust_method_entries void InstanceKlass::adjust_default_methods(Method** old_methods, Method** new_methods, int methods_length, bool* trace_name_printed) { // search the default_methods for uses of either obsolete or EMCP methods if (default_methods() != NULL) { for (int j = 0; j < methods_length; j++) { Method* old_method = old_methods[j]; Method* new_method = new_methods[j]; for (int index = 0; index < default_methods()->length(); index ++) { if (default_methods()->at(index) == old_method) { default_methods()->at_put(index, new_method); if (RC_TRACE_IN_RANGE(0x00100000, 0x00400000)) { if (!(*trace_name_printed)) { // RC_TRACE_MESG macro has an embedded ResourceMark RC_TRACE_MESG(("adjust: klassname=%s default methods from name=%s", external_name(), old_method->method_holder()->external_name())); *trace_name_printed = true; } RC_TRACE(0x00100000, ("default method update: %s(%s) ", new_method->name()->as_C_string(), new_method->signature()->as_C_string())); } } } } } } #endif // INCLUDE_JVMTI // On-stack replacement stuff void InstanceKlass::add_osr_nmethod(nmethod* n) { // only one compilation can be active NEEDS_CLEANUP // This is a short non-blocking critical region, so the no safepoint check is ok. OsrList_lock->lock_without_safepoint_check(); assert(n->is_osr_method(), "wrong kind of nmethod"); n->set_osr_link(osr_nmethods_head()); set_osr_nmethods_head(n); // Raise the highest osr level if necessary if (TieredCompilation) { Method* m = n->method(); m->set_highest_osr_comp_level(MAX2(m->highest_osr_comp_level(), n->comp_level())); } // Remember to unlock again OsrList_lock->unlock(); // Get rid of the osr methods for the same bci that have lower levels. if (TieredCompilation) { for (int l = CompLevel_limited_profile; l < n->comp_level(); l++) { nmethod *inv = lookup_osr_nmethod(n->method(), n->osr_entry_bci(), l, true); if (inv != NULL && inv->is_in_use()) { inv->make_not_entrant(); } } } } void InstanceKlass::remove_osr_nmethod(nmethod* n) { // This is a short non-blocking critical region, so the no safepoint check is ok. OsrList_lock->lock_without_safepoint_check(); assert(n->is_osr_method(), "wrong kind of nmethod"); nmethod* last = NULL; nmethod* cur = osr_nmethods_head(); int max_level = CompLevel_none; // Find the max comp level excluding n Method* m = n->method(); // Search for match while(cur != NULL && cur != n) { if (TieredCompilation && m == cur->method()) { // Find max level before n max_level = MAX2(max_level, cur->comp_level()); } last = cur; cur = cur->osr_link(); } nmethod* next = NULL; if (cur == n) { next = cur->osr_link(); if (last == NULL) { // Remove first element set_osr_nmethods_head(next); } else { last->set_osr_link(next); } } n->set_osr_link(NULL); if (TieredCompilation) { cur = next; while (cur != NULL) { // Find max level after n if (m == cur->method()) { max_level = MAX2(max_level, cur->comp_level()); } cur = cur->osr_link(); } m->set_highest_osr_comp_level(max_level); } // Remember to unlock again OsrList_lock->unlock(); } nmethod* InstanceKlass::lookup_osr_nmethod(const Method* m, int bci, int comp_level, bool match_level) const { // This is a short non-blocking critical region, so the no safepoint check is ok. OsrList_lock->lock_without_safepoint_check(); nmethod* osr = osr_nmethods_head(); nmethod* best = NULL; while (osr != NULL) { assert(osr->is_osr_method(), "wrong kind of nmethod found in chain"); // There can be a time when a c1 osr method exists but we are waiting // for a c2 version. When c2 completes its osr nmethod we will trash // the c1 version and only be able to find the c2 version. However // while we overflow in the c1 code at back branches we don't want to // try and switch to the same code as we are already running if (osr->method() == m && (bci == InvocationEntryBci || osr->osr_entry_bci() == bci)) { if (match_level) { if (osr->comp_level() == comp_level) { // Found a match - return it. OsrList_lock->unlock(); return osr; } } else { if (best == NULL || (osr->comp_level() > best->comp_level())) { if (osr->comp_level() == CompLevel_highest_tier) { // Found the best possible - return it. OsrList_lock->unlock(); return osr; } best = osr; } } } osr = osr->osr_link(); } OsrList_lock->unlock(); if (best != NULL && best->comp_level() >= comp_level && match_level == false) { return best; } return NULL; } void InstanceKlass::add_member_name(int index, Handle mem_name) { jweak mem_name_wref = JNIHandles::make_weak_global(mem_name); MutexLocker ml(MemberNameTable_lock); assert(0 <= index && index < idnum_allocated_count(), "index is out of bounds"); DEBUG_ONLY(No_Safepoint_Verifier nsv); if (_member_names == NULL) { _member_names = new (ResourceObj::C_HEAP, mtClass) MemberNameTable(idnum_allocated_count()); } _member_names->add_member_name(index, mem_name_wref); } oop InstanceKlass::get_member_name(int index) { MutexLocker ml(MemberNameTable_lock); assert(0 <= index && index < idnum_allocated_count(), "index is out of bounds"); DEBUG_ONLY(No_Safepoint_Verifier nsv); if (_member_names == NULL) { return NULL; } oop mem_name =_member_names->get_member_name(index); return mem_name; } // ----------------------------------------------------------------------------------------------------- // Printing #ifndef PRODUCT #define BULLET " - " static const char* state_names[] = { "allocated", "loaded", "linked", "being_initialized", "fully_initialized", "initialization_error" }; static void print_vtable(intptr_t* start, int len, outputStream* st) { for (int i = 0; i < len; i++) { intptr_t e = start[i]; st->print("%d : " INTPTR_FORMAT, i, e); if (e != 0 && ((Metadata*)e)->is_metaspace_object()) { st->print(" "); ((Metadata*)e)->print_value_on(st); } st->cr(); } } void InstanceKlass::print_on(outputStream* st) const { assert(is_klass(), "must be klass"); Klass::print_on(st); st->print(BULLET"instance size: %d", size_helper()); st->cr(); st->print(BULLET"klass size: %d", size()); st->cr(); st->print(BULLET"access: "); access_flags().print_on(st); st->cr(); st->print(BULLET"state: "); st->print_cr("%s", state_names[_init_state]); st->print(BULLET"name: "); name()->print_value_on(st); st->cr(); st->print(BULLET"super: "); super()->print_value_on_maybe_null(st); st->cr(); st->print(BULLET"sub: "); Klass* sub = subklass(); int n; for (n = 0; sub != NULL; n++, sub = sub->next_sibling()) { if (n < MaxSubklassPrintSize) { sub->print_value_on(st); st->print(" "); } } if (n >= MaxSubklassPrintSize) st->print("(%d more klasses...)", n - MaxSubklassPrintSize); st->cr(); if (is_interface()) { st->print_cr(BULLET"nof implementors: %d", nof_implementors()); if (nof_implementors() == 1) { st->print_cr(BULLET"implementor: "); st->print(" "); implementor()->print_value_on(st); st->cr(); } } st->print(BULLET"arrays: "); array_klasses()->print_value_on_maybe_null(st); st->cr(); st->print(BULLET"methods: "); methods()->print_value_on(st); st->cr(); if (Verbose || WizardMode) { Array* method_array = methods(); for (int i = 0; i < method_array->length(); i++) { st->print("%d : ", i); method_array->at(i)->print_value(); st->cr(); } } st->print(BULLET"method ordering: "); method_ordering()->print_value_on(st); st->cr(); st->print(BULLET"default_methods: "); default_methods()->print_value_on(st); st->cr(); if (Verbose && default_methods() != NULL) { Array* method_array = default_methods(); for (int i = 0; i < method_array->length(); i++) { st->print("%d : ", i); method_array->at(i)->print_value(); st->cr(); } } if (default_vtable_indices() != NULL) { st->print(BULLET"default vtable indices: "); default_vtable_indices()->print_value_on(st); st->cr(); } st->print(BULLET"local interfaces: "); local_interfaces()->print_value_on(st); st->cr(); st->print(BULLET"trans. interfaces: "); transitive_interfaces()->print_value_on(st); st->cr(); st->print(BULLET"constants: "); constants()->print_value_on(st); st->cr(); if (class_loader_data() != NULL) { st->print(BULLET"class loader data: "); class_loader_data()->print_value_on(st); st->cr(); } st->print(BULLET"host class: "); host_klass()->print_value_on_maybe_null(st); st->cr(); if (source_file_name() != NULL) { st->print(BULLET"source file: "); source_file_name()->print_value_on(st); st->cr(); } if (source_debug_extension() != NULL) { st->print(BULLET"source debug extension: "); st->print("%s", source_debug_extension()); st->cr(); } st->print(BULLET"class annotations: "); class_annotations()->print_value_on(st); st->cr(); st->print(BULLET"class type annotations: "); class_type_annotations()->print_value_on(st); st->cr(); st->print(BULLET"field annotations: "); fields_annotations()->print_value_on(st); st->cr(); st->print(BULLET"field type annotations: "); fields_type_annotations()->print_value_on(st); st->cr(); { bool have_pv = false; PreviousVersionWalker pvw(Thread::current(), (InstanceKlass*)this); for (PreviousVersionNode * pv_node = pvw.next_previous_version(); pv_node != NULL; pv_node = pvw.next_previous_version()) { if (!have_pv) st->print(BULLET"previous version: "); have_pv = true; pv_node->prev_constant_pool()->print_value_on(st); } if (have_pv) st->cr(); } // pvw is cleaned up if (generic_signature() != NULL) { st->print(BULLET"generic signature: "); generic_signature()->print_value_on(st); st->cr(); } st->print(BULLET"inner classes: "); inner_classes()->print_value_on(st); st->cr(); st->print(BULLET"java mirror: "); java_mirror()->print_value_on(st); st->cr(); st->print(BULLET"vtable length %d (start addr: " INTPTR_FORMAT ")", vtable_length(), start_of_vtable()); st->cr(); if (vtable_length() > 0 && (Verbose || WizardMode)) print_vtable(start_of_vtable(), vtable_length(), st); st->print(BULLET"itable length %d (start addr: " INTPTR_FORMAT ")", itable_length(), start_of_itable()); st->cr(); if (itable_length() > 0 && (Verbose || WizardMode)) print_vtable(start_of_itable(), itable_length(), st); st->print_cr(BULLET"---- static fields (%d words):", static_field_size()); FieldPrinter print_static_field(st); ((InstanceKlass*)this)->do_local_static_fields(&print_static_field); st->print_cr(BULLET"---- non-static fields (%d words):", nonstatic_field_size()); FieldPrinter print_nonstatic_field(st); ((InstanceKlass*)this)->do_nonstatic_fields(&print_nonstatic_field); st->print(BULLET"non-static oop maps: "); OopMapBlock* map = start_of_nonstatic_oop_maps(); OopMapBlock* end_map = map + nonstatic_oop_map_count(); while (map < end_map) { st->print("%d-%d ", map->offset(), map->offset() + heapOopSize*(map->count() - 1)); map++; } st->cr(); } #endif //PRODUCT void InstanceKlass::print_value_on(outputStream* st) const { assert(is_klass(), "must be klass"); if (Verbose || WizardMode) access_flags().print_on(st); name()->print_value_on(st); } #ifndef PRODUCT void FieldPrinter::do_field(fieldDescriptor* fd) { _st->print(BULLET); if (_obj == NULL) { fd->print_on(_st); _st->cr(); } else { fd->print_on_for(_st, _obj); _st->cr(); } } void InstanceKlass::oop_print_on(oop obj, outputStream* st) { Klass::oop_print_on(obj, st); if (this == SystemDictionary::String_klass()) { typeArrayOop value = java_lang_String::value(obj); juint offset = java_lang_String::offset(obj); juint length = java_lang_String::length(obj); if (value != NULL && value->is_typeArray() && offset <= (juint) value->length() && offset + length <= (juint) value->length()) { st->print(BULLET"string: "); java_lang_String::print(obj, st); st->cr(); if (!WizardMode) return; // that is enough } } st->print_cr(BULLET"---- fields (total size %d words):", oop_size(obj)); FieldPrinter print_field(st, obj); do_nonstatic_fields(&print_field); if (this == SystemDictionary::Class_klass()) { st->print(BULLET"signature: "); java_lang_Class::print_signature(obj, st); st->cr(); Klass* mirrored_klass = java_lang_Class::as_Klass(obj); st->print(BULLET"fake entry for mirror: "); mirrored_klass->print_value_on_maybe_null(st); st->cr(); Klass* array_klass = java_lang_Class::array_klass(obj); st->print(BULLET"fake entry for array: "); array_klass->print_value_on_maybe_null(st); st->cr(); st->print_cr(BULLET"fake entry for oop_size: %d", java_lang_Class::oop_size(obj)); st->print_cr(BULLET"fake entry for static_oop_field_count: %d", java_lang_Class::static_oop_field_count(obj)); Klass* real_klass = java_lang_Class::as_Klass(obj); if (real_klass != NULL && real_klass->oop_is_instance()) { InstanceKlass::cast(real_klass)->do_local_static_fields(&print_field); } } else if (this == SystemDictionary::MethodType_klass()) { st->print(BULLET"signature: "); java_lang_invoke_MethodType::print_signature(obj, st); st->cr(); } } #endif //PRODUCT void InstanceKlass::oop_print_value_on(oop obj, outputStream* st) { st->print("a "); name()->print_value_on(st); obj->print_address_on(st); if (this == SystemDictionary::String_klass() && java_lang_String::value(obj) != NULL) { ResourceMark rm; int len = java_lang_String::length(obj); int plen = (len < 24 ? len : 12); char* str = java_lang_String::as_utf8_string(obj, 0, plen); st->print(" = \"%s\"", str); if (len > plen) st->print("...[%d]", len); } else if (this == SystemDictionary::Class_klass()) { Klass* k = java_lang_Class::as_Klass(obj); st->print(" = "); if (k != NULL) { k->print_value_on(st); } else { const char* tname = type2name(java_lang_Class::primitive_type(obj)); st->print("%s", tname ? tname : "type?"); } } else if (this == SystemDictionary::MethodType_klass()) { st->print(" = "); java_lang_invoke_MethodType::print_signature(obj, st); } else if (java_lang_boxing_object::is_instance(obj)) { st->print(" = "); java_lang_boxing_object::print(obj, st); } else if (this == SystemDictionary::LambdaForm_klass()) { oop vmentry = java_lang_invoke_LambdaForm::vmentry(obj); if (vmentry != NULL) { st->print(" => "); vmentry->print_value_on(st); } } else if (this == SystemDictionary::MemberName_klass()) { Metadata* vmtarget = java_lang_invoke_MemberName::vmtarget(obj); if (vmtarget != NULL) { st->print(" = "); vmtarget->print_value_on(st); } else { java_lang_invoke_MemberName::clazz(obj)->print_value_on(st); st->print("."); java_lang_invoke_MemberName::name(obj)->print_value_on(st); } } } const char* InstanceKlass::internal_name() const { return external_name(); } #if INCLUDE_SERVICES // Size Statistics void InstanceKlass::collect_statistics(KlassSizeStats *sz) const { Klass::collect_statistics(sz); sz->_inst_size = HeapWordSize * size_helper(); sz->_vtab_bytes = HeapWordSize * align_object_offset(vtable_length()); sz->_itab_bytes = HeapWordSize * align_object_offset(itable_length()); sz->_nonstatic_oopmap_bytes = HeapWordSize * ((is_interface() || is_anonymous()) ? align_object_offset(nonstatic_oop_map_size()) : nonstatic_oop_map_size()); int n = 0; n += (sz->_methods_array_bytes = sz->count_array(methods())); n += (sz->_method_ordering_bytes = sz->count_array(method_ordering())); n += (sz->_local_interfaces_bytes = sz->count_array(local_interfaces())); n += (sz->_transitive_interfaces_bytes = sz->count_array(transitive_interfaces())); n += (sz->_fields_bytes = sz->count_array(fields())); n += (sz->_inner_classes_bytes = sz->count_array(inner_classes())); sz->_ro_bytes += n; const ConstantPool* cp = constants(); if (cp) { cp->collect_statistics(sz); } const Annotations* anno = annotations(); if (anno) { anno->collect_statistics(sz); } const Array* methods_array = methods(); if (methods()) { for (int i = 0; i < methods_array->length(); i++) { Method* method = methods_array->at(i); if (method) { sz->_method_count ++; method->collect_statistics(sz); } } } } #endif // INCLUDE_SERVICES // Verification class VerifyFieldClosure: public OopClosure { protected: template void do_oop_work(T* p) { oop obj = oopDesc::load_decode_heap_oop(p); if (!obj->is_oop_or_null()) { tty->print_cr("Failed: " PTR_FORMAT " -> " PTR_FORMAT, p, (address)obj); Universe::print(); guarantee(false, "boom"); } } public: virtual void do_oop(oop* p) { VerifyFieldClosure::do_oop_work(p); } virtual void do_oop(narrowOop* p) { VerifyFieldClosure::do_oop_work(p); } }; void InstanceKlass::verify_on(outputStream* st) { #ifndef PRODUCT // Avoid redundant verifies, this really should be in product. if (_verify_count == Universe::verify_count()) return; _verify_count = Universe::verify_count(); #endif // Verify Klass Klass::verify_on(st); // Verify that klass is present in ClassLoaderData guarantee(class_loader_data()->contains_klass(this), "this class isn't found in class loader data"); // Verify vtables if (is_linked()) { ResourceMark rm; // $$$ This used to be done only for m/s collections. Doing it // always seemed a valid generalization. (DLD -- 6/00) vtable()->verify(st); } // Verify first subklass if (subklass_oop() != NULL) { guarantee(subklass_oop()->is_klass(), "should be klass"); } // Verify siblings Klass* super = this->super(); Klass* sib = next_sibling(); if (sib != NULL) { if (sib == this) { fatal(err_msg("subclass points to itself " PTR_FORMAT, sib)); } guarantee(sib->is_klass(), "should be klass"); guarantee(sib->super() == super, "siblings should have same superklass"); } // Verify implementor fields Klass* im = implementor(); if (im != NULL) { guarantee(is_interface(), "only interfaces should have implementor set"); guarantee(im->is_klass(), "should be klass"); guarantee(!im->is_interface() || im == this, "implementors cannot be interfaces"); } // Verify local interfaces if (local_interfaces()) { Array* local_interfaces = this->local_interfaces(); for (int j = 0; j < local_interfaces->length(); j++) { Klass* e = local_interfaces->at(j); guarantee(e->is_klass() && e->is_interface(), "invalid local interface"); } } // Verify transitive interfaces if (transitive_interfaces() != NULL) { Array* transitive_interfaces = this->transitive_interfaces(); for (int j = 0; j < transitive_interfaces->length(); j++) { Klass* e = transitive_interfaces->at(j); guarantee(e->is_klass() && e->is_interface(), "invalid transitive interface"); } } // Verify methods if (methods() != NULL) { Array* methods = this->methods(); for (int j = 0; j < methods->length(); j++) { guarantee(methods->at(j)->is_method(), "non-method in methods array"); } for (int j = 0; j < methods->length() - 1; j++) { Method* m1 = methods->at(j); Method* m2 = methods->at(j + 1); guarantee(m1->name()->fast_compare(m2->name()) <= 0, "methods not sorted correctly"); } } // Verify method ordering if (method_ordering() != NULL) { Array* method_ordering = this->method_ordering(); int length = method_ordering->length(); if (JvmtiExport::can_maintain_original_method_order() || ((UseSharedSpaces || DumpSharedSpaces) && length != 0)) { guarantee(length == methods()->length(), "invalid method ordering length"); jlong sum = 0; for (int j = 0; j < length; j++) { int original_index = method_ordering->at(j); guarantee(original_index >= 0, "invalid method ordering index"); guarantee(original_index < length, "invalid method ordering index"); sum += original_index; } // Verify sum of indices 0,1,...,length-1 guarantee(sum == ((jlong)length*(length-1))/2, "invalid method ordering sum"); } else { guarantee(length == 0, "invalid method ordering length"); } } // Verify default methods if (default_methods() != NULL) { Array* methods = this->default_methods(); for (int j = 0; j < methods->length(); j++) { guarantee(methods->at(j)->is_method(), "non-method in methods array"); } for (int j = 0; j < methods->length() - 1; j++) { Method* m1 = methods->at(j); Method* m2 = methods->at(j + 1); guarantee(m1->name()->fast_compare(m2->name()) <= 0, "methods not sorted correctly"); } } // Verify JNI static field identifiers if (jni_ids() != NULL) { jni_ids()->verify(this); } // Verify other fields if (array_klasses() != NULL) { guarantee(array_klasses()->is_klass(), "should be klass"); } if (constants() != NULL) { guarantee(constants()->is_constantPool(), "should be constant pool"); } const Klass* host = host_klass(); if (host != NULL) { guarantee(host->is_klass(), "should be klass"); } } void InstanceKlass::oop_verify_on(oop obj, outputStream* st) { Klass::oop_verify_on(obj, st); VerifyFieldClosure blk; obj->oop_iterate_no_header(&blk); } // JNIid class for jfieldIDs only // Note to reviewers: // These JNI functions are just moved over to column 1 and not changed // in the compressed oops workspace. JNIid::JNIid(Klass* holder, int offset, JNIid* next) { _holder = holder; _offset = offset; _next = next; debug_only(_is_static_field_id = false;) } JNIid* JNIid::find(int offset) { JNIid* current = this; while (current != NULL) { if (current->offset() == offset) return current; current = current->next(); } return NULL; } void JNIid::deallocate(JNIid* current) { while (current != NULL) { JNIid* next = current->next(); delete current; current = next; } } void JNIid::verify(Klass* holder) { int first_field_offset = InstanceMirrorKlass::offset_of_static_fields(); int end_field_offset; end_field_offset = first_field_offset + (InstanceKlass::cast(holder)->static_field_size() * wordSize); JNIid* current = this; while (current != NULL) { guarantee(current->holder() == holder, "Invalid klass in JNIid"); #ifdef ASSERT int o = current->offset(); if (current->is_static_field_id()) { guarantee(o >= first_field_offset && o < end_field_offset, "Invalid static field offset in JNIid"); } #endif current = current->next(); } } #ifdef ASSERT void InstanceKlass::set_init_state(ClassState state) { bool good_state = is_shared() ? (_init_state <= state) : (_init_state < state); assert(good_state || state == allocated, "illegal state transition"); _init_state = (u1)state; } #endif // RedefineClasses() support for previous versions: // Purge previous versions static void purge_previous_versions_internal(InstanceKlass* ik, int emcp_method_count) { if (ik->previous_versions() != NULL) { // This klass has previous versions so see what we can cleanup // while it is safe to do so. int deleted_count = 0; // leave debugging breadcrumbs int live_count = 0; ClassLoaderData* loader_data = ik->class_loader_data() == NULL ? ClassLoaderData::the_null_class_loader_data() : ik->class_loader_data(); // RC_TRACE macro has an embedded ResourceMark RC_TRACE(0x00000200, ("purge: %s: previous version length=%d", ik->external_name(), ik->previous_versions()->length())); for (int i = ik->previous_versions()->length() - 1; i >= 0; i--) { // check the previous versions array PreviousVersionNode * pv_node = ik->previous_versions()->at(i); ConstantPool* cp_ref = pv_node->prev_constant_pool(); assert(cp_ref != NULL, "cp ref was unexpectedly cleared"); ConstantPool* pvcp = cp_ref; if (!pvcp->on_stack()) { // If the constant pool isn't on stack, none of the methods // are executing. Delete all the methods, the constant pool and // and this previous version node. GrowableArray* method_refs = pv_node->prev_EMCP_methods(); if (method_refs != NULL) { for (int j = method_refs->length() - 1; j >= 0; j--) { Method* method = method_refs->at(j); assert(method != NULL, "method ref was unexpectedly cleared"); method_refs->remove_at(j); // method will be freed with associated class. } } // Remove the constant pool delete pv_node; // Since we are traversing the array backwards, we don't have to // do anything special with the index. ik->previous_versions()->remove_at(i); deleted_count++; continue; } else { RC_TRACE(0x00000200, ("purge: previous version @%d is alive", i)); assert(pvcp->pool_holder() != NULL, "Constant pool with no holder"); guarantee (!loader_data->is_unloading(), "unloaded classes can't be on the stack"); live_count++; } // At least one method is live in this previous version, clean out // the others or mark them as obsolete. GrowableArray* method_refs = pv_node->prev_EMCP_methods(); if (method_refs != NULL) { RC_TRACE(0x00000200, ("purge: previous methods length=%d", method_refs->length())); for (int j = method_refs->length() - 1; j >= 0; j--) { Method* method = method_refs->at(j); assert(method != NULL, "method ref was unexpectedly cleared"); // Remove the emcp method if it's not executing // If it's been made obsolete by a redefinition of a non-emcp // method, mark it as obsolete but leave it to clean up later. if (!method->on_stack()) { method_refs->remove_at(j); } else if (emcp_method_count == 0) { method->set_is_obsolete(); } else { // RC_TRACE macro has an embedded ResourceMark RC_TRACE(0x00000200, ("purge: %s(%s): prev method @%d in version @%d is alive", method->name()->as_C_string(), method->signature()->as_C_string(), j, i)); } } } } assert(ik->previous_versions()->length() == live_count, "sanity check"); RC_TRACE(0x00000200, ("purge: previous version stats: live=%d, deleted=%d", live_count, deleted_count)); } } // External interface for use during class unloading. void InstanceKlass::purge_previous_versions(InstanceKlass* ik) { // Call with >0 emcp methods since they are not currently being redefined. purge_previous_versions_internal(ik, 1); } // Potentially add an information node that contains pointers to the // interesting parts of the previous version of the_class. // This is also where we clean out any unused references. // Note that while we delete nodes from the _previous_versions // array, we never delete the array itself until the klass is // unloaded. The has_been_redefined() query depends on that fact. // void InstanceKlass::add_previous_version(instanceKlassHandle ikh, BitMap* emcp_methods, int emcp_method_count) { assert(Thread::current()->is_VM_thread(), "only VMThread can add previous versions"); if (_previous_versions == NULL) { // This is the first previous version so make some space. // Start with 2 elements under the assumption that the class // won't be redefined much. _previous_versions = new (ResourceObj::C_HEAP, mtClass) GrowableArray(2, true); } ConstantPool* cp_ref = ikh->constants(); // RC_TRACE macro has an embedded ResourceMark RC_TRACE(0x00000400, ("adding previous version ref for %s @%d, EMCP_cnt=%d " "on_stack=%d", ikh->external_name(), _previous_versions->length(), emcp_method_count, cp_ref->on_stack())); // If the constant pool for this previous version of the class // is not marked as being on the stack, then none of the methods // in this previous version of the class are on the stack so // we don't need to create a new PreviousVersionNode. However, // we still need to examine older previous versions below. Array* old_methods = ikh->methods(); if (cp_ref->on_stack()) { PreviousVersionNode * pv_node = NULL; if (emcp_method_count == 0) { // non-shared ConstantPool gets a reference pv_node = new PreviousVersionNode(cp_ref, NULL); RC_TRACE(0x00000400, ("add: all methods are obsolete; flushing any EMCP refs")); } else { int local_count = 0; GrowableArray* method_refs = new (ResourceObj::C_HEAP, mtClass) GrowableArray(emcp_method_count, true); for (int i = 0; i < old_methods->length(); i++) { if (emcp_methods->at(i)) { // this old method is EMCP. Save it only if it's on the stack Method* old_method = old_methods->at(i); if (old_method->on_stack()) { method_refs->append(old_method); } if (++local_count >= emcp_method_count) { // no more EMCP methods so bail out now break; } } } // non-shared ConstantPool gets a reference pv_node = new PreviousVersionNode(cp_ref, method_refs); } // append new previous version. _previous_versions->append(pv_node); } // Since the caller is the VMThread and we are at a safepoint, this // is a good time to clear out unused references. RC_TRACE(0x00000400, ("add: previous version length=%d", _previous_versions->length())); // Purge previous versions not executing on the stack purge_previous_versions_internal(this, emcp_method_count); int obsolete_method_count = old_methods->length() - emcp_method_count; if (emcp_method_count != 0 && obsolete_method_count != 0 && _previous_versions->length() > 0) { // We have a mix of obsolete and EMCP methods so we have to // clear out any matching EMCP method entries the hard way. int local_count = 0; for (int i = 0; i < old_methods->length(); i++) { if (!emcp_methods->at(i)) { // only obsolete methods are interesting Method* old_method = old_methods->at(i); Symbol* m_name = old_method->name(); Symbol* m_signature = old_method->signature(); // we might not have added the last entry for (int j = _previous_versions->length() - 1; j >= 0; j--) { // check the previous versions array for non executing obsolete methods PreviousVersionNode * pv_node = _previous_versions->at(j); GrowableArray* method_refs = pv_node->prev_EMCP_methods(); if (method_refs == NULL) { // We have run into a PreviousVersion generation where // all methods were made obsolete during that generation's // RedefineClasses() operation. At the time of that // operation, all EMCP methods were flushed so we don't // have to go back any further. // // A NULL method_refs is different than an empty method_refs. // We cannot infer any optimizations about older generations // from an empty method_refs for the current generation. break; } for (int k = method_refs->length() - 1; k >= 0; k--) { Method* method = method_refs->at(k); if (!method->is_obsolete() && method->name() == m_name && method->signature() == m_signature) { // The current RedefineClasses() call has made all EMCP // versions of this method obsolete so mark it as obsolete // and remove the reference. RC_TRACE(0x00000400, ("add: %s(%s): flush obsolete method @%d in version @%d", m_name->as_C_string(), m_signature->as_C_string(), k, j)); method->set_is_obsolete(); // Leave obsolete methods on the previous version list to // clean up later. break; } } // The previous loop may not find a matching EMCP method, but // that doesn't mean that we can optimize and not go any // further back in the PreviousVersion generations. The EMCP // method for this generation could have already been deleted, // but there still may be an older EMCP method that has not // been deleted. } if (++local_count >= obsolete_method_count) { // no more obsolete methods so bail out now break; } } } } } // end add_previous_version() // Determine if InstanceKlass has a previous version. bool InstanceKlass::has_previous_version() const { return (_previous_versions != NULL && _previous_versions->length() > 0); } // end has_previous_version() Method* InstanceKlass::method_with_idnum(int idnum) { Method* m = NULL; if (idnum < methods()->length()) { m = methods()->at(idnum); } if (m == NULL || m->method_idnum() != idnum) { for (int index = 0; index < methods()->length(); ++index) { m = methods()->at(index); if (m->method_idnum() == idnum) { return m; } } // None found, return null for the caller to handle. return NULL; } return m; } jint InstanceKlass::get_cached_class_file_len() { return VM_RedefineClasses::get_cached_class_file_len(_cached_class_file); } unsigned char * InstanceKlass::get_cached_class_file_bytes() { return VM_RedefineClasses::get_cached_class_file_bytes(_cached_class_file); } // Construct a PreviousVersionNode entry for the array hung off // the InstanceKlass. PreviousVersionNode::PreviousVersionNode(ConstantPool* prev_constant_pool, GrowableArray* prev_EMCP_methods) { _prev_constant_pool = prev_constant_pool; _prev_EMCP_methods = prev_EMCP_methods; } // Destroy a PreviousVersionNode PreviousVersionNode::~PreviousVersionNode() { if (_prev_constant_pool != NULL) { _prev_constant_pool = NULL; } if (_prev_EMCP_methods != NULL) { delete _prev_EMCP_methods; } } // Construct a helper for walking the previous versions array PreviousVersionWalker::PreviousVersionWalker(Thread* thread, InstanceKlass *ik) { _thread = thread; _previous_versions = ik->previous_versions(); _current_index = 0; _current_p = NULL; _current_constant_pool_handle = constantPoolHandle(thread, ik->constants()); } // Return the interesting information for the next previous version // of the klass. Returns NULL if there are no more previous versions. PreviousVersionNode* PreviousVersionWalker::next_previous_version() { if (_previous_versions == NULL) { // no previous versions so nothing to return return NULL; } _current_p = NULL; // reset to NULL _current_constant_pool_handle = NULL; int length = _previous_versions->length(); while (_current_index < length) { PreviousVersionNode * pv_node = _previous_versions->at(_current_index++); // Save a handle to the constant pool for this previous version, // which keeps all the methods from being deallocated. _current_constant_pool_handle = constantPoolHandle(_thread, pv_node->prev_constant_pool()); _current_p = pv_node; return pv_node; } return NULL; } // end next_previous_version()