| /* |
| * Copyright (c) 2003, 2010, 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/dictionary.hpp" |
| #include "classfile/systemDictionary.hpp" |
| #include "oops/oop.inline.hpp" |
| #include "prims/jvmtiRedefineClassesTrace.hpp" |
| #include "services/classLoadingService.hpp" |
| #include "utilities/hashtable.inline.hpp" |
| |
| |
| DictionaryEntry* Dictionary::_current_class_entry = NULL; |
| int Dictionary::_current_class_index = 0; |
| |
| |
| Dictionary::Dictionary(int table_size) |
| : TwoOopHashtable<klassOop>(table_size, sizeof(DictionaryEntry)) { |
| _current_class_index = 0; |
| _current_class_entry = NULL; |
| }; |
| |
| |
| |
| Dictionary::Dictionary(int table_size, HashtableBucket* t, |
| int number_of_entries) |
| : TwoOopHashtable<klassOop>(table_size, sizeof(DictionaryEntry), t, number_of_entries) { |
| _current_class_index = 0; |
| _current_class_entry = NULL; |
| }; |
| |
| |
| DictionaryEntry* Dictionary::new_entry(unsigned int hash, klassOop klass, |
| oop loader) { |
| DictionaryEntry* entry; |
| entry = (DictionaryEntry*)Hashtable<klassOop>::new_entry(hash, klass); |
| entry->set_loader(loader); |
| entry->set_pd_set(NULL); |
| return entry; |
| } |
| |
| |
| DictionaryEntry* Dictionary::new_entry() { |
| DictionaryEntry* entry = (DictionaryEntry*)Hashtable<klassOop>::new_entry(0L, NULL); |
| entry->set_loader(NULL); |
| entry->set_pd_set(NULL); |
| return entry; |
| } |
| |
| |
| void Dictionary::free_entry(DictionaryEntry* entry) { |
| // avoid recursion when deleting linked list |
| while (entry->pd_set() != NULL) { |
| ProtectionDomainEntry* to_delete = entry->pd_set(); |
| entry->set_pd_set(to_delete->next()); |
| delete to_delete; |
| } |
| Hashtable<klassOop>::free_entry(entry); |
| } |
| |
| |
| bool DictionaryEntry::contains_protection_domain(oop protection_domain) const { |
| #ifdef ASSERT |
| if (protection_domain == instanceKlass::cast(klass())->protection_domain()) { |
| // Ensure this doesn't show up in the pd_set (invariant) |
| bool in_pd_set = false; |
| for (ProtectionDomainEntry* current = _pd_set; |
| current != NULL; |
| current = current->next()) { |
| if (current->protection_domain() == protection_domain) { |
| in_pd_set = true; |
| break; |
| } |
| } |
| if (in_pd_set) { |
| assert(false, "A klass's protection domain should not show up " |
| "in its sys. dict. PD set"); |
| } |
| } |
| #endif /* ASSERT */ |
| |
| if (protection_domain == instanceKlass::cast(klass())->protection_domain()) { |
| // Succeeds trivially |
| return true; |
| } |
| |
| for (ProtectionDomainEntry* current = _pd_set; |
| current != NULL; |
| current = current->next()) { |
| if (current->protection_domain() == protection_domain) return true; |
| } |
| return false; |
| } |
| |
| |
| void DictionaryEntry::add_protection_domain(oop protection_domain) { |
| assert_locked_or_safepoint(SystemDictionary_lock); |
| if (!contains_protection_domain(protection_domain)) { |
| ProtectionDomainEntry* new_head = |
| new ProtectionDomainEntry(protection_domain, _pd_set); |
| // Warning: Preserve store ordering. The SystemDictionary is read |
| // without locks. The new ProtectionDomainEntry must be |
| // complete before other threads can be allowed to see it |
| // via a store to _pd_set. |
| OrderAccess::release_store_ptr(&_pd_set, new_head); |
| } |
| if (TraceProtectionDomainVerification && WizardMode) { |
| print(); |
| } |
| } |
| |
| |
| bool Dictionary::do_unloading(BoolObjectClosure* is_alive) { |
| assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint"); |
| bool class_was_unloaded = false; |
| int index = 0; // Defined here for portability! Do not move |
| |
| // Remove unloadable entries and classes from system dictionary |
| // The placeholder array has been handled in always_strong_oops_do. |
| DictionaryEntry* probe = NULL; |
| for (index = 0; index < table_size(); index++) { |
| for (DictionaryEntry** p = bucket_addr(index); *p != NULL; ) { |
| probe = *p; |
| klassOop e = probe->klass(); |
| oop class_loader = probe->loader(); |
| |
| instanceKlass* ik = instanceKlass::cast(e); |
| if (ik->previous_versions() != NULL) { |
| // This klass has previous versions so see what we can cleanup |
| // while it is safe to do so. |
| |
| int gc_count = 0; // leave debugging breadcrumbs |
| int live_count = 0; |
| |
| // RC_TRACE macro has an embedded ResourceMark |
| RC_TRACE(0x00000200, ("unload: %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 for GC'ed weak refs |
| PreviousVersionNode * pv_node = ik->previous_versions()->at(i); |
| jobject cp_ref = pv_node->prev_constant_pool(); |
| assert(cp_ref != NULL, "cp ref was unexpectedly cleared"); |
| if (cp_ref == NULL) { |
| delete pv_node; |
| ik->previous_versions()->remove_at(i); |
| // Since we are traversing the array backwards, we don't have to |
| // do anything special with the index. |
| continue; // robustness |
| } |
| |
| constantPoolOop pvcp = (constantPoolOop)JNIHandles::resolve(cp_ref); |
| if (pvcp == NULL) { |
| // this entry has been GC'ed so remove it |
| delete pv_node; |
| ik->previous_versions()->remove_at(i); |
| // Since we are traversing the array backwards, we don't have to |
| // do anything special with the index. |
| gc_count++; |
| continue; |
| } else { |
| RC_TRACE(0x00000200, ("unload: previous version @%d is alive", i)); |
| if (is_alive->do_object_b(pvcp)) { |
| live_count++; |
| } else { |
| guarantee(false, "sanity check"); |
| } |
| } |
| |
| GrowableArray<jweak>* method_refs = pv_node->prev_EMCP_methods(); |
| if (method_refs != NULL) { |
| RC_TRACE(0x00000200, ("unload: previous methods length=%d", |
| method_refs->length())); |
| for (int j = method_refs->length() - 1; j >= 0; j--) { |
| jweak method_ref = method_refs->at(j); |
| assert(method_ref != NULL, "weak method ref was unexpectedly cleared"); |
| if (method_ref == NULL) { |
| method_refs->remove_at(j); |
| // Since we are traversing the array backwards, we don't have to |
| // do anything special with the index. |
| continue; // robustness |
| } |
| |
| methodOop method = (methodOop)JNIHandles::resolve(method_ref); |
| if (method == NULL) { |
| // this method entry has been GC'ed so remove it |
| JNIHandles::destroy_weak_global(method_ref); |
| method_refs->remove_at(j); |
| } else { |
| // RC_TRACE macro has an embedded ResourceMark |
| RC_TRACE(0x00000200, |
| ("unload: %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, |
| ("unload: previous version stats: live=%d, GC'ed=%d", live_count, |
| gc_count)); |
| } |
| |
| // Non-unloadable classes were handled in always_strong_oops_do |
| if (!is_strongly_reachable(class_loader, e)) { |
| // Entry was not visited in phase1 (negated test from phase1) |
| assert(class_loader != NULL, "unloading entry with null class loader"); |
| oop k_def_class_loader = ik->class_loader(); |
| |
| // Do we need to delete this system dictionary entry? |
| bool purge_entry = false; |
| |
| // Do we need to delete this system dictionary entry? |
| if (!is_alive->do_object_b(class_loader)) { |
| // If the loader is not live this entry should always be |
| // removed (will never be looked up again). Note that this is |
| // not the same as unloading the referred class. |
| if (k_def_class_loader == class_loader) { |
| // This is the defining entry, so the referred class is about |
| // to be unloaded. |
| // Notify the debugger and clean up the class. |
| guarantee(!is_alive->do_object_b(e), |
| "klass should not be live if defining loader is not"); |
| class_was_unloaded = true; |
| // notify the debugger |
| if (JvmtiExport::should_post_class_unload()) { |
| JvmtiExport::post_class_unload(ik->as_klassOop()); |
| } |
| |
| // notify ClassLoadingService of class unload |
| ClassLoadingService::notify_class_unloaded(ik); |
| |
| // Clean up C heap |
| ik->release_C_heap_structures(); |
| } |
| // Also remove this system dictionary entry. |
| purge_entry = true; |
| |
| } else { |
| // The loader in this entry is alive. If the klass is dead, |
| // the loader must be an initiating loader (rather than the |
| // defining loader). Remove this entry. |
| if (!is_alive->do_object_b(e)) { |
| guarantee(!is_alive->do_object_b(k_def_class_loader), |
| "defining loader should not be live if klass is not"); |
| // If we get here, the class_loader must not be the defining |
| // loader, it must be an initiating one. |
| assert(k_def_class_loader != class_loader, |
| "cannot have live defining loader and unreachable klass"); |
| |
| // Loader is live, but class and its defining loader are dead. |
| // Remove the entry. The class is going away. |
| purge_entry = true; |
| } |
| } |
| |
| if (purge_entry) { |
| *p = probe->next(); |
| if (probe == _current_class_entry) { |
| _current_class_entry = NULL; |
| } |
| free_entry(probe); |
| continue; |
| } |
| } |
| p = probe->next_addr(); |
| } |
| } |
| return class_was_unloaded; |
| } |
| |
| |
| void Dictionary::always_strong_classes_do(OopClosure* blk) { |
| // Follow all system classes and temporary placeholders in dictionary |
| for (int index = 0; index < table_size(); index++) { |
| for (DictionaryEntry *probe = bucket(index); |
| probe != NULL; |
| probe = probe->next()) { |
| klassOop e = probe->klass(); |
| oop class_loader = probe->loader(); |
| if (is_strongly_reachable(class_loader, e)) { |
| blk->do_oop((oop*)probe->klass_addr()); |
| if (class_loader != NULL) { |
| blk->do_oop(probe->loader_addr()); |
| } |
| probe->protection_domain_set_oops_do(blk); |
| } |
| } |
| } |
| } |
| |
| |
| // Just the classes from defining class loaders |
| void Dictionary::classes_do(void f(klassOop)) { |
| for (int index = 0; index < table_size(); index++) { |
| for (DictionaryEntry* probe = bucket(index); |
| probe != NULL; |
| probe = probe->next()) { |
| klassOop k = probe->klass(); |
| if (probe->loader() == instanceKlass::cast(k)->class_loader()) { |
| f(k); |
| } |
| } |
| } |
| } |
| |
| // Added for initialize_itable_for_klass to handle exceptions |
| // Just the classes from defining class loaders |
| void Dictionary::classes_do(void f(klassOop, TRAPS), TRAPS) { |
| for (int index = 0; index < table_size(); index++) { |
| for (DictionaryEntry* probe = bucket(index); |
| probe != NULL; |
| probe = probe->next()) { |
| klassOop k = probe->klass(); |
| if (probe->loader() == instanceKlass::cast(k)->class_loader()) { |
| f(k, CHECK); |
| } |
| } |
| } |
| } |
| |
| |
| // All classes, and their class loaders |
| // (added for helpers that use HandleMarks and ResourceMarks) |
| // Don't iterate over placeholders |
| void Dictionary::classes_do(void f(klassOop, oop, TRAPS), TRAPS) { |
| for (int index = 0; index < table_size(); index++) { |
| for (DictionaryEntry* probe = bucket(index); |
| probe != NULL; |
| probe = probe->next()) { |
| klassOop k = probe->klass(); |
| f(k, probe->loader(), CHECK); |
| } |
| } |
| } |
| |
| |
| // All classes, and their class loaders |
| // Don't iterate over placeholders |
| void Dictionary::classes_do(void f(klassOop, oop)) { |
| for (int index = 0; index < table_size(); index++) { |
| for (DictionaryEntry* probe = bucket(index); |
| probe != NULL; |
| probe = probe->next()) { |
| klassOop k = probe->klass(); |
| f(k, probe->loader()); |
| } |
| } |
| } |
| |
| |
| void Dictionary::oops_do(OopClosure* f) { |
| for (int index = 0; index < table_size(); index++) { |
| for (DictionaryEntry* probe = bucket(index); |
| probe != NULL; |
| probe = probe->next()) { |
| f->do_oop((oop*)probe->klass_addr()); |
| if (probe->loader() != NULL) { |
| f->do_oop(probe->loader_addr()); |
| } |
| probe->protection_domain_set_oops_do(f); |
| } |
| } |
| } |
| |
| |
| void Dictionary::methods_do(void f(methodOop)) { |
| for (int index = 0; index < table_size(); index++) { |
| for (DictionaryEntry* probe = bucket(index); |
| probe != NULL; |
| probe = probe->next()) { |
| klassOop k = probe->klass(); |
| if (probe->loader() == instanceKlass::cast(k)->class_loader()) { |
| // only take klass is we have the entry with the defining class loader |
| instanceKlass::cast(k)->methods_do(f); |
| } |
| } |
| } |
| } |
| |
| |
| klassOop Dictionary::try_get_next_class() { |
| while (true) { |
| if (_current_class_entry != NULL) { |
| klassOop k = _current_class_entry->klass(); |
| _current_class_entry = _current_class_entry->next(); |
| return k; |
| } |
| _current_class_index = (_current_class_index + 1) % table_size(); |
| _current_class_entry = bucket(_current_class_index); |
| } |
| // never reached |
| } |
| |
| |
| // Add a loaded class to the system dictionary. |
| // Readers of the SystemDictionary aren't always locked, so _buckets |
| // is volatile. The store of the next field in the constructor is |
| // also cast to volatile; we do this to ensure store order is maintained |
| // by the compilers. |
| |
| void Dictionary::add_klass(Symbol* class_name, Handle class_loader, |
| KlassHandle obj) { |
| assert_locked_or_safepoint(SystemDictionary_lock); |
| assert(obj() != NULL, "adding NULL obj"); |
| assert(Klass::cast(obj())->name() == class_name, "sanity check on name"); |
| |
| unsigned int hash = compute_hash(class_name, class_loader); |
| int index = hash_to_index(hash); |
| DictionaryEntry* entry = new_entry(hash, obj(), class_loader()); |
| add_entry(index, entry); |
| } |
| |
| |
| // This routine does not lock the system dictionary. |
| // |
| // Since readers don't hold a lock, we must make sure that system |
| // dictionary entries are only removed at a safepoint (when only one |
| // thread is running), and are added to in a safe way (all links must |
| // be updated in an MT-safe manner). |
| // |
| // Callers should be aware that an entry could be added just after |
| // _buckets[index] is read here, so the caller will not see the new entry. |
| DictionaryEntry* Dictionary::get_entry(int index, unsigned int hash, |
| Symbol* class_name, |
| Handle class_loader) { |
| oop loader = class_loader(); |
| debug_only(_lookup_count++); |
| for (DictionaryEntry* entry = bucket(index); |
| entry != NULL; |
| entry = entry->next()) { |
| if (entry->hash() == hash && entry->equals(class_name, loader)) { |
| return entry; |
| } |
| debug_only(_lookup_length++); |
| } |
| return NULL; |
| } |
| |
| |
| klassOop Dictionary::find(int index, unsigned int hash, Symbol* name, |
| Handle loader, Handle protection_domain, TRAPS) { |
| DictionaryEntry* entry = get_entry(index, hash, name, loader); |
| if (entry != NULL && entry->is_valid_protection_domain(protection_domain)) { |
| return entry->klass(); |
| } else { |
| return NULL; |
| } |
| } |
| |
| |
| klassOop Dictionary::find_class(int index, unsigned int hash, |
| Symbol* name, Handle loader) { |
| assert_locked_or_safepoint(SystemDictionary_lock); |
| assert (index == index_for(name, loader), "incorrect index?"); |
| |
| DictionaryEntry* entry = get_entry(index, hash, name, loader); |
| return (entry != NULL) ? entry->klass() : (klassOop)NULL; |
| } |
| |
| |
| // Variant of find_class for shared classes. No locking required, as |
| // that table is static. |
| |
| klassOop Dictionary::find_shared_class(int index, unsigned int hash, |
| Symbol* name) { |
| assert (index == index_for(name, Handle()), "incorrect index?"); |
| |
| DictionaryEntry* entry = get_entry(index, hash, name, Handle()); |
| return (entry != NULL) ? entry->klass() : (klassOop)NULL; |
| } |
| |
| |
| void Dictionary::add_protection_domain(int index, unsigned int hash, |
| instanceKlassHandle klass, |
| Handle loader, Handle protection_domain, |
| TRAPS) { |
| Symbol* klass_name = klass->name(); |
| DictionaryEntry* entry = get_entry(index, hash, klass_name, loader); |
| |
| assert(entry != NULL,"entry must be present, we just created it"); |
| assert(protection_domain() != NULL, |
| "real protection domain should be present"); |
| |
| entry->add_protection_domain(protection_domain()); |
| |
| assert(entry->contains_protection_domain(protection_domain()), |
| "now protection domain should be present"); |
| } |
| |
| |
| bool Dictionary::is_valid_protection_domain(int index, unsigned int hash, |
| Symbol* name, |
| Handle loader, |
| Handle protection_domain) { |
| DictionaryEntry* entry = get_entry(index, hash, name, loader); |
| return entry->is_valid_protection_domain(protection_domain); |
| } |
| |
| |
| void Dictionary::reorder_dictionary() { |
| |
| // Copy all the dictionary entries into a single master list. |
| |
| DictionaryEntry* master_list = NULL; |
| for (int i = 0; i < table_size(); ++i) { |
| DictionaryEntry* p = bucket(i); |
| while (p != NULL) { |
| DictionaryEntry* tmp; |
| tmp = p->next(); |
| p->set_next(master_list); |
| master_list = p; |
| p = tmp; |
| } |
| set_entry(i, NULL); |
| } |
| |
| // Add the dictionary entries back to the list in the correct buckets. |
| Thread *thread = Thread::current(); |
| |
| while (master_list != NULL) { |
| DictionaryEntry* p = master_list; |
| master_list = master_list->next(); |
| p->set_next(NULL); |
| Symbol* class_name = instanceKlass::cast((klassOop)(p->klass()))->name(); |
| unsigned int hash = compute_hash(class_name, Handle(thread, p->loader())); |
| int index = hash_to_index(hash); |
| p->set_hash(hash); |
| p->set_next(bucket(index)); |
| set_entry(index, p); |
| } |
| } |
| |
| SymbolPropertyTable::SymbolPropertyTable(int table_size) |
| : Hashtable<Symbol*>(table_size, sizeof(SymbolPropertyEntry)) |
| { |
| } |
| SymbolPropertyTable::SymbolPropertyTable(int table_size, HashtableBucket* t, |
| int number_of_entries) |
| : Hashtable<Symbol*>(table_size, sizeof(SymbolPropertyEntry), t, number_of_entries) |
| { |
| } |
| |
| |
| SymbolPropertyEntry* SymbolPropertyTable::find_entry(int index, unsigned int hash, |
| Symbol* sym, |
| intptr_t sym_mode) { |
| assert(index == index_for(sym, sym_mode), "incorrect index?"); |
| for (SymbolPropertyEntry* p = bucket(index); p != NULL; p = p->next()) { |
| if (p->hash() == hash && p->symbol() == sym && p->symbol_mode() == sym_mode) { |
| return p; |
| } |
| } |
| return NULL; |
| } |
| |
| |
| SymbolPropertyEntry* SymbolPropertyTable::add_entry(int index, unsigned int hash, |
| Symbol* sym, intptr_t sym_mode) { |
| assert_locked_or_safepoint(SystemDictionary_lock); |
| assert(index == index_for(sym, sym_mode), "incorrect index?"); |
| assert(find_entry(index, hash, sym, sym_mode) == NULL, "no double entry"); |
| |
| SymbolPropertyEntry* p = new_entry(hash, sym, sym_mode); |
| Hashtable<Symbol*>::add_entry(index, p); |
| return p; |
| } |
| |
| |
| void SymbolPropertyTable::oops_do(OopClosure* f) { |
| for (int index = 0; index < table_size(); index++) { |
| for (SymbolPropertyEntry* p = bucket(index); p != NULL; p = p->next()) { |
| if (p->property_oop() != NULL) { |
| f->do_oop(p->property_oop_addr()); |
| } |
| } |
| } |
| } |
| |
| void SymbolPropertyTable::methods_do(void f(methodOop)) { |
| for (int index = 0; index < table_size(); index++) { |
| for (SymbolPropertyEntry* p = bucket(index); p != NULL; p = p->next()) { |
| oop prop = p->property_oop(); |
| if (prop != NULL && prop->is_method()) { |
| f((methodOop)prop); |
| } |
| } |
| } |
| } |
| |
| |
| // ---------------------------------------------------------------------------- |
| #ifndef PRODUCT |
| |
| void Dictionary::print() { |
| ResourceMark rm; |
| HandleMark hm; |
| |
| tty->print_cr("Java system dictionary (classes=%d)", number_of_entries()); |
| tty->print_cr("^ indicates that initiating loader is different from " |
| "defining loader"); |
| |
| for (int index = 0; index < table_size(); index++) { |
| for (DictionaryEntry* probe = bucket(index); |
| probe != NULL; |
| probe = probe->next()) { |
| if (Verbose) tty->print("%4d: ", index); |
| klassOop e = probe->klass(); |
| oop class_loader = probe->loader(); |
| bool is_defining_class = |
| (class_loader == instanceKlass::cast(e)->class_loader()); |
| tty->print("%s%s", is_defining_class ? " " : "^", |
| Klass::cast(e)->external_name()); |
| if (class_loader != NULL) { |
| tty->print(", loader "); |
| class_loader->print_value(); |
| } |
| tty->cr(); |
| } |
| } |
| } |
| |
| #endif |
| |
| void Dictionary::verify() { |
| guarantee(number_of_entries() >= 0, "Verify of system dictionary failed"); |
| int element_count = 0; |
| for (int index = 0; index < table_size(); index++) { |
| for (DictionaryEntry* probe = bucket(index); |
| probe != NULL; |
| probe = probe->next()) { |
| klassOop e = probe->klass(); |
| oop class_loader = probe->loader(); |
| guarantee(Klass::cast(e)->oop_is_instance(), |
| "Verify of system dictionary failed"); |
| // class loader must be present; a null class loader is the |
| // boostrap loader |
| guarantee(class_loader == NULL || class_loader->is_instance(), |
| "checking type of class_loader"); |
| e->verify(); |
| probe->verify_protection_domain_set(); |
| element_count++; |
| } |
| } |
| guarantee(number_of_entries() == element_count, |
| "Verify of system dictionary failed"); |
| debug_only(verify_lookup_length((double)number_of_entries() / table_size())); |
| } |