truffle: src/share/vm/classfile/dictionary.cpp comparison

comparison src/share/vm/classfile/dictionary.cpp @ 0:a61af66fc99e jdk7-b24

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author	duke
date	Sat, 01 Dec 2007 00:00:00 +0000
parents
children	2c106685d6d0

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--1:000000000000
+:a61af66fc99e
+/*
+* Copyright 2003-2007 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+* CA 95054 USA or visit www.sun.com if you need additional information or
+* have any questions.
+*
+*/
+# include "incls/_precompiled.incl"
+# include "incls/_dictionary.cpp.incl"
+DictionaryEntry*  Dictionary::_current_class_entry = NULL;
+int               Dictionary::_current_class_index =    0;
+Dictionary::Dictionary(int table_size)
+: TwoOopHashtable(table_size, sizeof(DictionaryEntry)) {
+_current_class_index = 0;
+_current_class_entry = NULL;
+};
+Dictionary::Dictionary(int table_size, HashtableBucket* t,
+int number_of_entries)
+: TwoOopHashtable(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::new_entry(hash, klass);
+entry->set_loader(loader);
+entry->set_pd_set(NULL);
+return entry;
+}
+DictionaryEntry* Dictionary::new_entry() {
+DictionaryEntry* entry = (DictionaryEntry*)Hashtable::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::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);
+jweak cp_ref = pv_node->prev_constant_pool();
+assert(cp_ref != NULL, "weak 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()) {
+oop 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(symbolHandle 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,
+symbolHandle class_name,
+Handle class_loader) {
+symbolOop name_ = class_name();
+oop loader_ = class_loader();
+debug_only(_lookup_count++);
+for (DictionaryEntry* entry = bucket(index);
+entry != NULL;
+entry = entry->next()) {
+if (entry->hash() == hash && entry->equals(name_, loader_)) {
+return entry;
+}
+debug_only(_lookup_length++);
+}
+return NULL;
+}
+klassOop Dictionary::find(int index, unsigned int hash, symbolHandle 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,
+symbolHandle 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,
+symbolHandle 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) {
+symbolHandle klass_name(THREAD, 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,
+symbolHandle 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);
+symbolHandle class_name (thread, 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);
+}
+}
+// ----------------------------------------------------------------------------
+#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()));
+}

Mercurial > hg > truffle

comparison src/share/vm/classfile/dictionary.cpp @ 0:a61af66fc99e jdk7-b24