duke@435: /* xdono@631: * Copyright 1997-2008 Sun Microsystems, Inc. All Rights Reserved. duke@435: * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. duke@435: * duke@435: * This code is free software; you can redistribute it and/or modify it duke@435: * under the terms of the GNU General Public License version 2 only, as duke@435: * published by the Free Software Foundation. duke@435: * duke@435: * This code is distributed in the hope that it will be useful, but WITHOUT duke@435: * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or duke@435: * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License duke@435: * version 2 for more details (a copy is included in the LICENSE file that duke@435: * accompanied this code). duke@435: * duke@435: * You should have received a copy of the GNU General Public License version duke@435: * 2 along with this work; if not, write to the Free Software Foundation, duke@435: * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. duke@435: * duke@435: * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, duke@435: * CA 95054 USA or visit www.sun.com if you need additional information or duke@435: * have any questions. duke@435: * duke@435: */ duke@435: duke@435: # include "incls/_precompiled.incl" duke@435: # include "incls/_systemDictionary.cpp.incl" duke@435: duke@435: duke@435: Dictionary* SystemDictionary::_dictionary = NULL; duke@435: PlaceholderTable* SystemDictionary::_placeholders = NULL; duke@435: Dictionary* SystemDictionary::_shared_dictionary = NULL; duke@435: LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL; duke@435: ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL; duke@435: duke@435: duke@435: int SystemDictionary::_number_of_modifications = 0; duke@435: duke@435: oop SystemDictionary::_system_loader_lock_obj = NULL; duke@435: jrose@567: klassOop SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT] jrose@567: = { NULL /*, NULL...*/ }; duke@435: duke@435: klassOop SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ }; duke@435: duke@435: oop SystemDictionary::_java_system_loader = NULL; duke@435: duke@435: bool SystemDictionary::_has_loadClassInternal = false; duke@435: bool SystemDictionary::_has_checkPackageAccess = false; duke@435: duke@435: // lazily initialized klass variables duke@435: volatile klassOop SystemDictionary::_abstract_ownable_synchronizer_klass = NULL; duke@435: duke@435: duke@435: // ---------------------------------------------------------------------------- duke@435: // Java-level SystemLoader duke@435: duke@435: oop SystemDictionary::java_system_loader() { duke@435: return _java_system_loader; duke@435: } duke@435: duke@435: void SystemDictionary::compute_java_system_loader(TRAPS) { jrose@567: KlassHandle system_klass(THREAD, WK_KLASS(classloader_klass)); duke@435: JavaValue result(T_OBJECT); duke@435: JavaCalls::call_static(&result, jrose@567: KlassHandle(THREAD, WK_KLASS(classloader_klass)), duke@435: vmSymbolHandles::getSystemClassLoader_name(), duke@435: vmSymbolHandles::void_classloader_signature(), duke@435: CHECK); duke@435: duke@435: _java_system_loader = (oop)result.get_jobject(); duke@435: } duke@435: duke@435: duke@435: // ---------------------------------------------------------------------------- duke@435: // debugging duke@435: duke@435: #ifdef ASSERT duke@435: duke@435: // return true if class_name contains no '.' (internal format is '/') duke@435: bool SystemDictionary::is_internal_format(symbolHandle class_name) { duke@435: if (class_name.not_null()) { duke@435: ResourceMark rm; duke@435: char* name = class_name->as_C_string(); duke@435: return strchr(name, '.') == NULL; duke@435: } else { duke@435: return true; duke@435: } duke@435: } duke@435: duke@435: #endif duke@435: duke@435: // ---------------------------------------------------------------------------- acorn@949: // Parallel class loading check acorn@949: acorn@949: bool SystemDictionary::is_parallelCapable(Handle class_loader) { acorn@949: if (UnsyncloadClass || class_loader.is_null()) return true; acorn@949: if (AlwaysLockClassLoader) return false; acorn@949: return java_lang_Class::parallelCapable(class_loader()); acorn@949: } acorn@949: // ---------------------------------------------------------------------------- duke@435: // Resolving of classes duke@435: duke@435: // Forwards to resolve_or_null duke@435: duke@435: klassOop SystemDictionary::resolve_or_fail(symbolHandle class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) { duke@435: klassOop klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD); duke@435: if (HAS_PENDING_EXCEPTION || klass == NULL) { duke@435: KlassHandle k_h(THREAD, klass); duke@435: // can return a null klass duke@435: klass = handle_resolution_exception(class_name, class_loader, protection_domain, throw_error, k_h, THREAD); duke@435: } duke@435: return klass; duke@435: } duke@435: duke@435: klassOop SystemDictionary::handle_resolution_exception(symbolHandle class_name, Handle class_loader, Handle protection_domain, bool throw_error, KlassHandle klass_h, TRAPS) { duke@435: if (HAS_PENDING_EXCEPTION) { duke@435: // If we have a pending exception we forward it to the caller, unless throw_error is true, duke@435: // in which case we have to check whether the pending exception is a ClassNotFoundException, duke@435: // and if so convert it to a NoClassDefFoundError duke@435: // And chain the original ClassNotFoundException duke@435: if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::classNotFoundException_klass())) { duke@435: ResourceMark rm(THREAD); duke@435: assert(klass_h() == NULL, "Should not have result with exception pending"); duke@435: Handle e(THREAD, PENDING_EXCEPTION); duke@435: CLEAR_PENDING_EXCEPTION; duke@435: THROW_MSG_CAUSE_0(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e); duke@435: } else { duke@435: return NULL; duke@435: } duke@435: } duke@435: // Class not found, throw appropriate error or exception depending on value of throw_error duke@435: if (klass_h() == NULL) { duke@435: ResourceMark rm(THREAD); duke@435: if (throw_error) { duke@435: THROW_MSG_0(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string()); duke@435: } else { duke@435: THROW_MSG_0(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string()); duke@435: } duke@435: } duke@435: return (klassOop)klass_h(); duke@435: } duke@435: duke@435: duke@435: klassOop SystemDictionary::resolve_or_fail(symbolHandle class_name, duke@435: bool throw_error, TRAPS) duke@435: { duke@435: return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD); duke@435: } duke@435: duke@435: duke@435: // Forwards to resolve_instance_class_or_null duke@435: duke@435: klassOop SystemDictionary::resolve_or_null(symbolHandle class_name, Handle class_loader, Handle protection_domain, TRAPS) { duke@435: assert(!THREAD->is_Compiler_thread(), "Can not load classes with the Compiler thread"); duke@435: if (FieldType::is_array(class_name())) { duke@435: return resolve_array_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL); duke@435: } else { duke@435: return resolve_instance_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL); duke@435: } duke@435: } duke@435: duke@435: klassOop SystemDictionary::resolve_or_null(symbolHandle class_name, TRAPS) { duke@435: return resolve_or_null(class_name, Handle(), Handle(), THREAD); duke@435: } duke@435: duke@435: // Forwards to resolve_instance_class_or_null duke@435: duke@435: klassOop SystemDictionary::resolve_array_class_or_null(symbolHandle class_name, duke@435: Handle class_loader, duke@435: Handle protection_domain, duke@435: TRAPS) { duke@435: assert(FieldType::is_array(class_name()), "must be array"); duke@435: jint dimension; duke@435: symbolOop object_key; duke@435: klassOop k = NULL; duke@435: // dimension and object_key are assigned as a side-effect of this call duke@435: BasicType t = FieldType::get_array_info(class_name(), duke@435: &dimension, duke@435: &object_key, duke@435: CHECK_NULL); duke@435: duke@435: if (t == T_OBJECT) { duke@435: symbolHandle h_key(THREAD, object_key); duke@435: // naked oop "k" is OK here -- we assign back into it duke@435: k = SystemDictionary::resolve_instance_class_or_null(h_key, duke@435: class_loader, duke@435: protection_domain, duke@435: CHECK_NULL); duke@435: if (k != NULL) { duke@435: k = Klass::cast(k)->array_klass(dimension, CHECK_NULL); duke@435: } duke@435: } else { duke@435: k = Universe::typeArrayKlassObj(t); duke@435: k = typeArrayKlass::cast(k)->array_klass(dimension, CHECK_NULL); duke@435: } duke@435: return k; duke@435: } duke@435: duke@435: duke@435: // Must be called for any super-class or super-interface resolution duke@435: // during class definition to allow class circularity checking duke@435: // super-interface callers: duke@435: // parse_interfaces - for defineClass & jvmtiRedefineClasses duke@435: // super-class callers: duke@435: // ClassFileParser - for defineClass & jvmtiRedefineClasses duke@435: // load_shared_class - while loading a class from shared archive acorn@949: // resolve_instance_class_or_null: acorn@949: // via: handle_parallel_super_load duke@435: // when resolving a class that has an existing placeholder with duke@435: // a saved superclass [i.e. a defineClass is currently in progress] duke@435: // if another thread is trying to resolve the class, it must do duke@435: // super-class checks on its own thread to catch class circularity duke@435: // This last call is critical in class circularity checking for cases duke@435: // where classloading is delegated to different threads and the duke@435: // classloader lock is released. duke@435: // Take the case: Base->Super->Base duke@435: // 1. If thread T1 tries to do a defineClass of class Base duke@435: // resolve_super_or_fail creates placeholder: T1, Base (super Super) duke@435: // 2. resolve_instance_class_or_null does not find SD or placeholder for Super duke@435: // so it tries to load Super duke@435: // 3. If we load the class internally, or user classloader uses same thread duke@435: // loadClassFromxxx or defineClass via parseClassFile Super ... duke@435: // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base) duke@435: // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base duke@435: // 3.4 calls resolve_super_or_fail Base duke@435: // 3.5 finds T1,Base -> throws class circularity duke@435: //OR 4. If T2 tries to resolve Super via defineClass Super ... duke@435: // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base) duke@435: // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super) duke@435: // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2 duke@435: // 4.4 finds T2, Super -> throws class circularity duke@435: // Must be called, even if superclass is null, since this is duke@435: // where the placeholder entry is created which claims this duke@435: // thread is loading this class/classloader. duke@435: klassOop SystemDictionary::resolve_super_or_fail(symbolHandle child_name, duke@435: symbolHandle class_name, duke@435: Handle class_loader, duke@435: Handle protection_domain, duke@435: bool is_superclass, duke@435: TRAPS) { duke@435: jrose@567: // Try to get one of the well-known klasses. jrose@567: // They are trusted, and do not participate in circularities. jrose@567: if (LinkWellKnownClasses) { jrose@567: klassOop k = find_well_known_klass(class_name()); jrose@567: if (k != NULL) { jrose@567: return k; jrose@567: } jrose@567: } jrose@567: duke@435: // Double-check, if child class is already loaded, just return super-class,interface duke@435: // Don't add a placedholder if already loaded, i.e. already in system dictionary duke@435: // Make sure there's a placeholder for the *child* before resolving. duke@435: // Used as a claim that this thread is currently loading superclass/classloader duke@435: // Used here for ClassCircularity checks and also for heap verification duke@435: // (every instanceKlass in the heap needs to be in the system dictionary duke@435: // or have a placeholder). duke@435: // Must check ClassCircularity before checking if super class is already loaded duke@435: // duke@435: // We might not already have a placeholder if this child_name was duke@435: // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass); duke@435: // the name of the class might not be known until the stream is actually duke@435: // parsed. duke@435: // Bugs 4643874, 4715493 duke@435: // compute_hash can have a safepoint duke@435: duke@435: unsigned int d_hash = dictionary()->compute_hash(child_name, class_loader); duke@435: int d_index = dictionary()->hash_to_index(d_hash); duke@435: unsigned int p_hash = placeholders()->compute_hash(child_name, class_loader); duke@435: int p_index = placeholders()->hash_to_index(p_hash); duke@435: // can't throw error holding a lock duke@435: bool child_already_loaded = false; duke@435: bool throw_circularity_error = false; duke@435: { duke@435: MutexLocker mu(SystemDictionary_lock, THREAD); duke@435: klassOop childk = find_class(d_index, d_hash, child_name, class_loader); duke@435: klassOop quicksuperk; duke@435: // to support // loading: if child done loading, just return superclass duke@435: // if class_name, & class_loader don't match: duke@435: // if initial define, SD update will give LinkageError duke@435: // if redefine: compare_class_versions will give HIERARCHY_CHANGED duke@435: // so we don't throw an exception here. duke@435: // see: nsk redefclass014 & java.lang.instrument Instrument032 duke@435: if ((childk != NULL ) && (is_superclass) && duke@435: ((quicksuperk = instanceKlass::cast(childk)->super()) != NULL) && duke@435: duke@435: ((Klass::cast(quicksuperk)->name() == class_name()) && duke@435: (Klass::cast(quicksuperk)->class_loader() == class_loader()))) { duke@435: return quicksuperk; duke@435: } else { duke@435: PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, class_loader); duke@435: if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) { duke@435: throw_circularity_error = true; duke@435: } acorn@949: } acorn@949: if (!throw_circularity_error) { duke@435: PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, class_loader, PlaceholderTable::LOAD_SUPER, class_name, THREAD); duke@435: } duke@435: } duke@435: if (throw_circularity_error) { duke@435: ResourceMark rm(THREAD); duke@435: THROW_MSG_0(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string()); duke@435: } duke@435: duke@435: // java.lang.Object should have been found above duke@435: assert(class_name() != NULL, "null super class for resolving"); duke@435: // Resolve the super class or interface, check results on return duke@435: klassOop superk = NULL; duke@435: superk = SystemDictionary::resolve_or_null(class_name, duke@435: class_loader, duke@435: protection_domain, duke@435: THREAD); duke@435: duke@435: KlassHandle superk_h(THREAD, superk); duke@435: duke@435: // Note: clean up of placeholders currently in callers of duke@435: // resolve_super_or_fail - either at update_dictionary time duke@435: // or on error duke@435: { duke@435: MutexLocker mu(SystemDictionary_lock, THREAD); duke@435: PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, class_loader); duke@435: if (probe != NULL) { duke@435: probe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER); duke@435: } duke@435: } duke@435: if (HAS_PENDING_EXCEPTION || superk_h() == NULL) { duke@435: // can null superk duke@435: superk_h = KlassHandle(THREAD, handle_resolution_exception(class_name, class_loader, protection_domain, true, superk_h, THREAD)); duke@435: } duke@435: duke@435: return superk_h(); duke@435: } duke@435: duke@435: void SystemDictionary::validate_protection_domain(instanceKlassHandle klass, duke@435: Handle class_loader, duke@435: Handle protection_domain, duke@435: TRAPS) { duke@435: if(!has_checkPackageAccess()) return; duke@435: duke@435: // Now we have to call back to java to check if the initating class has access duke@435: JavaValue result(T_VOID); duke@435: if (TraceProtectionDomainVerification) { duke@435: // Print out trace information duke@435: tty->print_cr("Checking package access"); duke@435: tty->print(" - class loader: "); class_loader()->print_value_on(tty); tty->cr(); duke@435: tty->print(" - protection domain: "); protection_domain()->print_value_on(tty); tty->cr(); duke@435: tty->print(" - loading: "); klass()->print_value_on(tty); tty->cr(); duke@435: } duke@435: duke@435: assert(class_loader() != NULL, "should not have non-null protection domain for null classloader"); duke@435: duke@435: KlassHandle system_loader(THREAD, SystemDictionary::classloader_klass()); duke@435: JavaCalls::call_special(&result, duke@435: class_loader, duke@435: system_loader, duke@435: vmSymbolHandles::checkPackageAccess_name(), duke@435: vmSymbolHandles::class_protectiondomain_signature(), duke@435: Handle(THREAD, klass->java_mirror()), duke@435: protection_domain, duke@435: THREAD); duke@435: duke@435: if (TraceProtectionDomainVerification) { duke@435: if (HAS_PENDING_EXCEPTION) { duke@435: tty->print_cr(" -> DENIED !!!!!!!!!!!!!!!!!!!!!"); duke@435: } else { duke@435: tty->print_cr(" -> granted"); duke@435: } duke@435: tty->cr(); duke@435: } duke@435: duke@435: if (HAS_PENDING_EXCEPTION) return; duke@435: duke@435: // If no exception has been thrown, we have validated the protection domain duke@435: // Insert the protection domain of the initiating class into the set. duke@435: { duke@435: // We recalculate the entry here -- we've called out to java since duke@435: // the last time it was calculated. duke@435: symbolHandle kn(THREAD, klass->name()); duke@435: unsigned int d_hash = dictionary()->compute_hash(kn, class_loader); duke@435: int d_index = dictionary()->hash_to_index(d_hash); duke@435: duke@435: MutexLocker mu(SystemDictionary_lock, THREAD); duke@435: { duke@435: // Note that we have an entry, and entries can be deleted only during GC, duke@435: // so we cannot allow GC to occur while we're holding this entry. duke@435: duke@435: // We're using a No_Safepoint_Verifier to catch any place where we duke@435: // might potentially do a GC at all. duke@435: // SystemDictionary::do_unloading() asserts that classes are only duke@435: // unloaded at a safepoint. duke@435: No_Safepoint_Verifier nosafepoint; duke@435: dictionary()->add_protection_domain(d_index, d_hash, klass, class_loader, duke@435: protection_domain, THREAD); duke@435: } duke@435: } duke@435: } duke@435: duke@435: // We only get here if this thread finds that another thread duke@435: // has already claimed the placeholder token for the current operation, duke@435: // but that other thread either never owned or gave up the duke@435: // object lock duke@435: // Waits on SystemDictionary_lock to indicate placeholder table updated duke@435: // On return, caller must recheck placeholder table state duke@435: // duke@435: // We only get here if duke@435: // 1) custom classLoader, i.e. not bootstrap classloader duke@435: // 2) UnsyncloadClass not set duke@435: // 3) custom classLoader has broken the class loader objectLock duke@435: // so another thread got here in parallel duke@435: // duke@435: // lockObject must be held. duke@435: // Complicated dance due to lock ordering: duke@435: // Must first release the classloader object lock to duke@435: // allow initial definer to complete the class definition duke@435: // and to avoid deadlock duke@435: // Reclaim classloader lock object with same original recursion count duke@435: // Must release SystemDictionary_lock after notify, since duke@435: // class loader lock must be claimed before SystemDictionary_lock duke@435: // to prevent deadlocks duke@435: // duke@435: // The notify allows applications that did an untimed wait() on duke@435: // the classloader object lock to not hang. duke@435: void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) { duke@435: assert_lock_strong(SystemDictionary_lock); duke@435: duke@435: bool calledholdinglock duke@435: = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject); duke@435: assert(calledholdinglock,"must hold lock for notify"); acorn@949: assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait"); duke@435: ObjectSynchronizer::notifyall(lockObject, THREAD); duke@435: intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD); duke@435: SystemDictionary_lock->wait(); duke@435: SystemDictionary_lock->unlock(); duke@435: ObjectSynchronizer::reenter(lockObject, recursions, THREAD); duke@435: SystemDictionary_lock->lock(); duke@435: } duke@435: duke@435: // If the class in is in the placeholder table, class loading is in progress duke@435: // For cases where the application changes threads to load classes, it duke@435: // is critical to ClassCircularity detection that we try loading duke@435: // the superclass on the same thread internally, so we do parallel duke@435: // super class loading here. duke@435: // This also is critical in cases where the original thread gets stalled duke@435: // even in non-circularity situations. duke@435: // Note: only one thread can define the class, but multiple can resolve duke@435: // Note: must call resolve_super_or_fail even if null super - acorn@949: // to force placeholder entry creation for this class for circularity detection duke@435: // Caller must check for pending exception duke@435: // Returns non-null klassOop if other thread has completed load duke@435: // and we are done, duke@435: // If return null klassOop and no pending exception, the caller must load the class duke@435: instanceKlassHandle SystemDictionary::handle_parallel_super_load( duke@435: symbolHandle name, symbolHandle superclassname, Handle class_loader, duke@435: Handle protection_domain, Handle lockObject, TRAPS) { duke@435: duke@435: instanceKlassHandle nh = instanceKlassHandle(); // null Handle duke@435: unsigned int d_hash = dictionary()->compute_hash(name, class_loader); duke@435: int d_index = dictionary()->hash_to_index(d_hash); duke@435: unsigned int p_hash = placeholders()->compute_hash(name, class_loader); duke@435: int p_index = placeholders()->hash_to_index(p_hash); duke@435: duke@435: // superk is not used, resolve_super called for circularity check only duke@435: // This code is reached in two situations. One if this thread duke@435: // is loading the same class twice (e.g. ClassCircularity, or duke@435: // java.lang.instrument). duke@435: // The second is if another thread started the resolve_super first duke@435: // and has not yet finished. duke@435: // In both cases the original caller will clean up the placeholder duke@435: // entry on error. duke@435: klassOop superk = SystemDictionary::resolve_super_or_fail(name, duke@435: superclassname, duke@435: class_loader, duke@435: protection_domain, duke@435: true, duke@435: CHECK_(nh)); duke@435: // We don't redefine the class, so we just need to clean up if there duke@435: // was not an error (don't want to modify any system dictionary duke@435: // data structures). duke@435: { duke@435: MutexLocker mu(SystemDictionary_lock, THREAD); duke@435: placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD); duke@435: SystemDictionary_lock->notify_all(); duke@435: } duke@435: acorn@949: // parallelCapable class loaders do NOT wait for parallel superclass loads to complete acorn@949: // Serial class loaders and bootstrap classloader do wait for superclass loads acorn@949: if (!class_loader.is_null() && is_parallelCapable(class_loader)) { duke@435: MutexLocker mu(SystemDictionary_lock, THREAD); duke@435: // Check if classloading completed while we were loading superclass or waiting duke@435: klassOop check = find_class(d_index, d_hash, name, class_loader); duke@435: if (check != NULL) { duke@435: // Klass is already loaded, so just return it duke@435: return(instanceKlassHandle(THREAD, check)); duke@435: } else { duke@435: return nh; duke@435: } duke@435: } duke@435: duke@435: // must loop to both handle other placeholder updates duke@435: // and spurious notifications duke@435: bool super_load_in_progress = true; duke@435: PlaceholderEntry* placeholder; duke@435: while (super_load_in_progress) { duke@435: MutexLocker mu(SystemDictionary_lock, THREAD); duke@435: // Check if classloading completed while we were loading superclass or waiting duke@435: klassOop check = find_class(d_index, d_hash, name, class_loader); duke@435: if (check != NULL) { duke@435: // Klass is already loaded, so just return it duke@435: return(instanceKlassHandle(THREAD, check)); duke@435: } else { duke@435: placeholder = placeholders()->get_entry(p_index, p_hash, name, class_loader); duke@435: if (placeholder && placeholder->super_load_in_progress() ){ duke@435: // Before UnsyncloadClass: duke@435: // We only get here if the application has released the duke@435: // classloader lock when another thread was in the middle of loading a duke@435: // superclass/superinterface for this class, and now duke@435: // this thread is also trying to load this class. duke@435: // To minimize surprises, the first thread that started to duke@435: // load a class should be the one to complete the loading duke@435: // with the classfile it initially expected. duke@435: // This logic has the current thread wait once it has done duke@435: // all the superclass/superinterface loading it can, until duke@435: // the original thread completes the class loading or fails duke@435: // If it completes we will use the resulting instanceKlass duke@435: // which we will find below in the systemDictionary. duke@435: // We also get here for parallel bootstrap classloader duke@435: if (class_loader.is_null()) { duke@435: SystemDictionary_lock->wait(); duke@435: } else { duke@435: double_lock_wait(lockObject, THREAD); duke@435: } duke@435: } else { duke@435: // If not in SD and not in PH, other thread's load must have failed duke@435: super_load_in_progress = false; duke@435: } duke@435: } duke@435: } duke@435: return (nh); duke@435: } duke@435: duke@435: duke@435: klassOop SystemDictionary::resolve_instance_class_or_null(symbolHandle class_name, Handle class_loader, Handle protection_domain, TRAPS) { duke@435: assert(class_name.not_null() && !FieldType::is_array(class_name()), "invalid class name"); duke@435: // First check to see if we should remove wrapping L and ; duke@435: symbolHandle name; duke@435: if (FieldType::is_obj(class_name())) { duke@435: ResourceMark rm(THREAD); duke@435: // Ignore wrapping L and ;. duke@435: name = oopFactory::new_symbol_handle(class_name()->as_C_string() + 1, class_name()->utf8_length() - 2, CHECK_NULL); duke@435: } else { duke@435: name = class_name; duke@435: } duke@435: duke@435: // UseNewReflection duke@435: // Fix for 4474172; see evaluation for more details duke@435: class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader())); duke@435: duke@435: // Do lookup to see if class already exist and the protection domain duke@435: // has the right access duke@435: unsigned int d_hash = dictionary()->compute_hash(name, class_loader); duke@435: int d_index = dictionary()->hash_to_index(d_hash); duke@435: klassOop probe = dictionary()->find(d_index, d_hash, name, class_loader, duke@435: protection_domain, THREAD); duke@435: if (probe != NULL) return probe; duke@435: duke@435: duke@435: // Non-bootstrap class loaders will call out to class loader and duke@435: // define via jvm/jni_DefineClass which will acquire the duke@435: // class loader object lock to protect against multiple threads duke@435: // defining the class in parallel by accident. duke@435: // This lock must be acquired here so the waiter will find duke@435: // any successful result in the SystemDictionary and not attempt duke@435: // the define acorn@949: // ParallelCapable Classloaders and the bootstrap classloader, duke@435: // or all classloaders with UnsyncloadClass do not acquire lock here duke@435: bool DoObjectLock = true; acorn@949: if (is_parallelCapable(class_loader)) { duke@435: DoObjectLock = false; duke@435: } duke@435: duke@435: unsigned int p_hash = placeholders()->compute_hash(name, class_loader); duke@435: int p_index = placeholders()->hash_to_index(p_hash); duke@435: duke@435: // Class is not in SystemDictionary so we have to do loading. duke@435: // Make sure we are synchronized on the class loader before we proceed duke@435: Handle lockObject = compute_loader_lock_object(class_loader, THREAD); duke@435: check_loader_lock_contention(lockObject, THREAD); duke@435: ObjectLocker ol(lockObject, THREAD, DoObjectLock); duke@435: duke@435: // Check again (after locking) if class already exist in SystemDictionary duke@435: bool class_has_been_loaded = false; duke@435: bool super_load_in_progress = false; duke@435: bool havesupername = false; duke@435: instanceKlassHandle k; duke@435: PlaceholderEntry* placeholder; duke@435: symbolHandle superclassname; duke@435: duke@435: { duke@435: MutexLocker mu(SystemDictionary_lock, THREAD); duke@435: klassOop check = find_class(d_index, d_hash, name, class_loader); duke@435: if (check != NULL) { duke@435: // Klass is already loaded, so just return it duke@435: class_has_been_loaded = true; duke@435: k = instanceKlassHandle(THREAD, check); duke@435: } else { duke@435: placeholder = placeholders()->get_entry(p_index, p_hash, name, class_loader); duke@435: if (placeholder && placeholder->super_load_in_progress()) { duke@435: super_load_in_progress = true; duke@435: if (placeholder->havesupername() == true) { duke@435: superclassname = symbolHandle(THREAD, placeholder->supername()); duke@435: havesupername = true; duke@435: } duke@435: } duke@435: } duke@435: } duke@435: duke@435: // If the class in is in the placeholder table, class loading is in progress duke@435: if (super_load_in_progress && havesupername==true) { duke@435: k = SystemDictionary::handle_parallel_super_load(name, superclassname, duke@435: class_loader, protection_domain, lockObject, THREAD); duke@435: if (HAS_PENDING_EXCEPTION) { duke@435: return NULL; duke@435: } duke@435: if (!k.is_null()) { duke@435: class_has_been_loaded = true; duke@435: } duke@435: } duke@435: duke@435: if (!class_has_been_loaded) { duke@435: duke@435: // add placeholder entry to record loading instance class duke@435: // Five cases: duke@435: // All cases need to prevent modifying bootclasssearchpath duke@435: // in parallel with a classload of same classname acorn@949: // Redefineclasses uses existence of the placeholder for the duration acorn@949: // of the class load to prevent concurrent redefinition of not completely acorn@949: // defined classes. duke@435: // case 1. traditional classloaders that rely on the classloader object lock duke@435: // - no other need for LOAD_INSTANCE duke@435: // case 2. traditional classloaders that break the classloader object lock duke@435: // as a deadlock workaround. Detection of this case requires that duke@435: // this check is done while holding the classloader object lock, duke@435: // and that lock is still held when calling classloader's loadClass. duke@435: // For these classloaders, we ensure that the first requestor duke@435: // completes the load and other requestors wait for completion. duke@435: // case 3. UnsyncloadClass - don't use objectLocker duke@435: // With this flag, we allow parallel classloading of a duke@435: // class/classloader pair duke@435: // case4. Bootstrap classloader - don't own objectLocker duke@435: // This classloader supports parallelism at the classloader level, duke@435: // but only allows a single load of a class/classloader pair. duke@435: // No performance benefit and no deadlock issues. acorn@949: // case 5. parallelCapable user level classloaders - without objectLocker acorn@949: // Allow parallel classloading of a class/classloader pair duke@435: symbolHandle nullsymbolHandle; duke@435: bool throw_circularity_error = false; duke@435: { duke@435: MutexLocker mu(SystemDictionary_lock, THREAD); acorn@949: if (class_loader.is_null() || !is_parallelCapable(class_loader)) { duke@435: PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, class_loader); duke@435: if (oldprobe) { duke@435: // only need check_seen_thread once, not on each loop duke@435: // 6341374 java/lang/Instrument with -Xcomp duke@435: if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) { duke@435: throw_circularity_error = true; duke@435: } else { duke@435: // case 1: traditional: should never see load_in_progress. duke@435: while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) { duke@435: duke@435: // case 4: bootstrap classloader: prevent futile classloading, duke@435: // wait on first requestor duke@435: if (class_loader.is_null()) { duke@435: SystemDictionary_lock->wait(); duke@435: } else { duke@435: // case 2: traditional with broken classloader lock. wait on first duke@435: // requestor. duke@435: double_lock_wait(lockObject, THREAD); duke@435: } duke@435: // Check if classloading completed while we were waiting duke@435: klassOop check = find_class(d_index, d_hash, name, class_loader); duke@435: if (check != NULL) { duke@435: // Klass is already loaded, so just return it duke@435: k = instanceKlassHandle(THREAD, check); duke@435: class_has_been_loaded = true; duke@435: } duke@435: // check if other thread failed to load and cleaned up duke@435: oldprobe = placeholders()->get_entry(p_index, p_hash, name, class_loader); duke@435: } duke@435: } duke@435: } duke@435: } duke@435: // All cases: add LOAD_INSTANCE acorn@949: // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try duke@435: // LOAD_INSTANCE in parallel duke@435: // add placeholder entry even if error - callers will remove on error acorn@949: if (!throw_circularity_error && !class_has_been_loaded) { duke@435: PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, class_loader, PlaceholderTable::LOAD_INSTANCE, nullsymbolHandle, THREAD); duke@435: // For class loaders that do not acquire the classloader object lock, duke@435: // if they did not catch another thread holding LOAD_INSTANCE, duke@435: // need a check analogous to the acquire ObjectLocker/find_class duke@435: // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL duke@435: // one final check if the load has already completed acorn@949: // class loaders holding the ObjectLock shouldn't find the class here duke@435: klassOop check = find_class(d_index, d_hash, name, class_loader); duke@435: if (check != NULL) { duke@435: // Klass is already loaded, so just return it duke@435: k = instanceKlassHandle(THREAD, check); duke@435: class_has_been_loaded = true; duke@435: newprobe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE); acorn@949: placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD); acorn@949: SystemDictionary_lock->notify_all(); duke@435: } duke@435: } duke@435: } duke@435: // must throw error outside of owning lock duke@435: if (throw_circularity_error) { duke@435: ResourceMark rm(THREAD); duke@435: THROW_MSG_0(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string()); duke@435: } duke@435: duke@435: if (!class_has_been_loaded) { duke@435: duke@435: // Do actual loading duke@435: k = load_instance_class(name, class_loader, THREAD); duke@435: acorn@949: // For UnsyncloadClass and AllowParallelDefineClass only: duke@435: // If they got a linkageError, check if a parallel class load succeeded. duke@435: // If it did, then for bytecode resolution the specification requires duke@435: // that we return the same result we did for the other thread, i.e. the duke@435: // successfully loaded instanceKlass duke@435: // Should not get here for classloaders that support parallelism acorn@949: // with the new cleaner mechanism acorn@949: // Bootstrap goes through here to allow for an extra guarantee check duke@435: if (UnsyncloadClass || (class_loader.is_null())) { duke@435: if (k.is_null() && HAS_PENDING_EXCEPTION duke@435: && PENDING_EXCEPTION->is_a(SystemDictionary::linkageError_klass())) { duke@435: MutexLocker mu(SystemDictionary_lock, THREAD); duke@435: klassOop check = find_class(d_index, d_hash, name, class_loader); duke@435: if (check != NULL) { duke@435: // Klass is already loaded, so just use it duke@435: k = instanceKlassHandle(THREAD, check); duke@435: CLEAR_PENDING_EXCEPTION; duke@435: guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?"); duke@435: } duke@435: } duke@435: } duke@435: duke@435: // clean up placeholder entries for success or error duke@435: // This cleans up LOAD_INSTANCE entries duke@435: // It also cleans up LOAD_SUPER entries on errors from duke@435: // calling load_instance_class duke@435: { duke@435: MutexLocker mu(SystemDictionary_lock, THREAD); duke@435: PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name, class_loader); duke@435: if (probe != NULL) { duke@435: probe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE); duke@435: placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD); duke@435: SystemDictionary_lock->notify_all(); duke@435: } duke@435: } duke@435: duke@435: // If everything was OK (no exceptions, no null return value), and duke@435: // class_loader is NOT the defining loader, do a little more bookkeeping. duke@435: if (!HAS_PENDING_EXCEPTION && !k.is_null() && duke@435: k->class_loader() != class_loader()) { duke@435: duke@435: check_constraints(d_index, d_hash, k, class_loader, false, THREAD); duke@435: duke@435: // Need to check for a PENDING_EXCEPTION again; check_constraints duke@435: // can throw and doesn't use the CHECK macro. duke@435: if (!HAS_PENDING_EXCEPTION) { duke@435: { // Grabbing the Compile_lock prevents systemDictionary updates duke@435: // during compilations. duke@435: MutexLocker mu(Compile_lock, THREAD); duke@435: update_dictionary(d_index, d_hash, p_index, p_hash, duke@435: k, class_loader, THREAD); duke@435: } duke@435: if (JvmtiExport::should_post_class_load()) { duke@435: Thread *thread = THREAD; duke@435: assert(thread->is_Java_thread(), "thread->is_Java_thread()"); duke@435: JvmtiExport::post_class_load((JavaThread *) thread, k()); duke@435: } duke@435: } duke@435: } duke@435: if (HAS_PENDING_EXCEPTION || k.is_null()) { duke@435: // On error, clean up placeholders duke@435: { duke@435: MutexLocker mu(SystemDictionary_lock, THREAD); duke@435: placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD); duke@435: SystemDictionary_lock->notify_all(); duke@435: } duke@435: return NULL; duke@435: } duke@435: } duke@435: } duke@435: duke@435: #ifdef ASSERT duke@435: { duke@435: Handle loader (THREAD, k->class_loader()); duke@435: MutexLocker mu(SystemDictionary_lock, THREAD); duke@435: oop kk = find_class_or_placeholder(name, loader); duke@435: assert(kk == k(), "should be present in dictionary"); duke@435: } duke@435: #endif duke@435: duke@435: // return if the protection domain in NULL duke@435: if (protection_domain() == NULL) return k(); duke@435: duke@435: // Check the protection domain has the right access duke@435: { duke@435: MutexLocker mu(SystemDictionary_lock, THREAD); duke@435: // Note that we have an entry, and entries can be deleted only during GC, duke@435: // so we cannot allow GC to occur while we're holding this entry. duke@435: // We're using a No_Safepoint_Verifier to catch any place where we duke@435: // might potentially do a GC at all. duke@435: // SystemDictionary::do_unloading() asserts that classes are only duke@435: // unloaded at a safepoint. duke@435: No_Safepoint_Verifier nosafepoint; duke@435: if (dictionary()->is_valid_protection_domain(d_index, d_hash, name, duke@435: class_loader, duke@435: protection_domain)) { duke@435: return k(); duke@435: } duke@435: } duke@435: duke@435: // Verify protection domain. If it fails an exception is thrown duke@435: validate_protection_domain(k, class_loader, protection_domain, CHECK_(klassOop(NULL))); duke@435: duke@435: return k(); duke@435: } duke@435: duke@435: duke@435: // This routine does not lock the system dictionary. duke@435: // duke@435: // Since readers don't hold a lock, we must make sure that system duke@435: // dictionary entries are only removed at a safepoint (when only one duke@435: // thread is running), and are added to in a safe way (all links must duke@435: // be updated in an MT-safe manner). duke@435: // duke@435: // Callers should be aware that an entry could be added just after duke@435: // _dictionary->bucket(index) is read here, so the caller will not see duke@435: // the new entry. duke@435: duke@435: klassOop SystemDictionary::find(symbolHandle class_name, duke@435: Handle class_loader, duke@435: Handle protection_domain, duke@435: TRAPS) { duke@435: kvn@991: // UseNewReflection kvn@991: // The result of this call should be consistent with the result kvn@991: // of the call to resolve_instance_class_or_null(). kvn@991: // See evaluation 6790209 and 4474172 for more details. kvn@991: class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader())); kvn@991: duke@435: unsigned int d_hash = dictionary()->compute_hash(class_name, class_loader); duke@435: int d_index = dictionary()->hash_to_index(d_hash); duke@435: duke@435: { duke@435: // Note that we have an entry, and entries can be deleted only during GC, duke@435: // so we cannot allow GC to occur while we're holding this entry. duke@435: // We're using a No_Safepoint_Verifier to catch any place where we duke@435: // might potentially do a GC at all. duke@435: // SystemDictionary::do_unloading() asserts that classes are only duke@435: // unloaded at a safepoint. duke@435: No_Safepoint_Verifier nosafepoint; duke@435: return dictionary()->find(d_index, d_hash, class_name, class_loader, duke@435: protection_domain, THREAD); duke@435: } duke@435: } duke@435: duke@435: duke@435: // Look for a loaded instance or array klass by name. Do not do any loading. duke@435: // return NULL in case of error. duke@435: klassOop SystemDictionary::find_instance_or_array_klass(symbolHandle class_name, duke@435: Handle class_loader, duke@435: Handle protection_domain, duke@435: TRAPS) { duke@435: klassOop k = NULL; duke@435: assert(class_name() != NULL, "class name must be non NULL"); jrose@567: jrose@567: // Try to get one of the well-known klasses. jrose@567: if (LinkWellKnownClasses) { jrose@567: k = find_well_known_klass(class_name()); jrose@567: if (k != NULL) { jrose@567: return k; jrose@567: } jrose@567: } jrose@567: duke@435: if (FieldType::is_array(class_name())) { duke@435: // The name refers to an array. Parse the name. duke@435: jint dimension; duke@435: symbolOop object_key; duke@435: duke@435: // dimension and object_key are assigned as a side-effect of this call duke@435: BasicType t = FieldType::get_array_info(class_name(), &dimension, duke@435: &object_key, CHECK_(NULL)); duke@435: if (t != T_OBJECT) { duke@435: k = Universe::typeArrayKlassObj(t); duke@435: } else { duke@435: symbolHandle h_key(THREAD, object_key); duke@435: k = SystemDictionary::find(h_key, class_loader, protection_domain, THREAD); duke@435: } duke@435: if (k != NULL) { duke@435: k = Klass::cast(k)->array_klass_or_null(dimension); duke@435: } duke@435: } else { duke@435: k = find(class_name, class_loader, protection_domain, THREAD); duke@435: } duke@435: return k; duke@435: } duke@435: jrose@567: // Quick range check for names of well-known classes: jrose@567: static symbolOop wk_klass_name_limits[2] = {NULL, NULL}; jrose@567: jrose@567: #ifndef PRODUCT jrose@567: static int find_wkk_calls, find_wkk_probes, find_wkk_wins; jrose@567: // counts for "hello world": 3983, 1616, 1075 jrose@567: // => 60% hit after limit guard, 25% total win rate jrose@567: #endif jrose@567: jrose@567: klassOop SystemDictionary::find_well_known_klass(symbolOop class_name) { jrose@567: // A bounds-check on class_name will quickly get a negative result. jrose@567: NOT_PRODUCT(find_wkk_calls++); jrose@567: if (class_name >= wk_klass_name_limits[0] && jrose@567: class_name <= wk_klass_name_limits[1]) { jrose@567: NOT_PRODUCT(find_wkk_probes++); jrose@567: vmSymbols::SID sid = vmSymbols::find_sid(class_name); jrose@567: if (sid != vmSymbols::NO_SID) { jrose@567: klassOop k = NULL; jrose@567: switch (sid) { jrose@567: #define WK_KLASS_CASE(name, symbol, ignore_option) \ jrose@567: case vmSymbols::VM_SYMBOL_ENUM_NAME(symbol): \ jrose@567: k = WK_KLASS(name); break; jrose@567: WK_KLASSES_DO(WK_KLASS_CASE) jrose@567: #undef WK_KLASS_CASE jrose@567: } jrose@567: NOT_PRODUCT(if (k != NULL) find_wkk_wins++); jrose@567: return k; jrose@567: } jrose@567: } jrose@567: return NULL; jrose@567: } jrose@567: duke@435: // Note: this method is much like resolve_from_stream, but duke@435: // updates no supplemental data structures. duke@435: // TODO consolidate the two methods with a helper routine? duke@435: klassOop SystemDictionary::parse_stream(symbolHandle class_name, duke@435: Handle class_loader, duke@435: Handle protection_domain, duke@435: ClassFileStream* st, jrose@866: KlassHandle host_klass, jrose@866: GrowableArray* cp_patches, duke@435: TRAPS) { duke@435: symbolHandle parsed_name; duke@435: duke@435: // Parse the stream. Note that we do this even though this klass might duke@435: // already be present in the SystemDictionary, otherwise we would not duke@435: // throw potential ClassFormatErrors. duke@435: // duke@435: // Note: "name" is updated. duke@435: // Further note: a placeholder will be added for this class when duke@435: // super classes are loaded (resolve_super_or_fail). We expect this duke@435: // to be called for all classes but java.lang.Object; and we preload duke@435: // java.lang.Object through resolve_or_fail, not this path. duke@435: duke@435: instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name, duke@435: class_loader, duke@435: protection_domain, duke@435: parsed_name, duke@435: THREAD); duke@435: acorn@949: duke@435: // We don't redefine the class, so we just need to clean up whether there duke@435: // was an error or not (don't want to modify any system dictionary duke@435: // data structures). duke@435: // Parsed name could be null if we threw an error before we got far duke@435: // enough along to parse it -- in that case, there is nothing to clean up. duke@435: if (!parsed_name.is_null()) { duke@435: unsigned int p_hash = placeholders()->compute_hash(parsed_name, duke@435: class_loader); duke@435: int p_index = placeholders()->hash_to_index(p_hash); duke@435: { duke@435: MutexLocker mu(SystemDictionary_lock, THREAD); duke@435: placeholders()->find_and_remove(p_index, p_hash, parsed_name, class_loader, THREAD); duke@435: SystemDictionary_lock->notify_all(); duke@435: } duke@435: } duke@435: jrose@866: if (host_klass.not_null() && k.not_null()) { jrose@866: assert(AnonymousClasses, ""); jrose@866: // If it's anonymous, initialize it now, since nobody else will. jrose@866: k->set_host_klass(host_klass()); jrose@866: jrose@866: { jrose@866: MutexLocker mu_r(Compile_lock, THREAD); jrose@866: jrose@866: // Add to class hierarchy, initialize vtables, and do possible jrose@866: // deoptimizations. jrose@866: add_to_hierarchy(k, CHECK_NULL); // No exception, but can block jrose@866: jrose@866: // But, do not add to system dictionary. jrose@866: } jrose@866: jrose@866: k->eager_initialize(THREAD); jrose@866: jrose@866: // notify jvmti jrose@866: if (JvmtiExport::should_post_class_load()) { jrose@866: assert(THREAD->is_Java_thread(), "thread->is_Java_thread()"); jrose@866: JvmtiExport::post_class_load((JavaThread *) THREAD, k()); jrose@866: } jrose@866: } jrose@866: duke@435: return k(); duke@435: } duke@435: duke@435: // Add a klass to the system from a stream (called by jni_DefineClass and duke@435: // JVM_DefineClass). duke@435: // Note: class_name can be NULL. In that case we do not know the name of duke@435: // the class until we have parsed the stream. duke@435: duke@435: klassOop SystemDictionary::resolve_from_stream(symbolHandle class_name, duke@435: Handle class_loader, duke@435: Handle protection_domain, duke@435: ClassFileStream* st, duke@435: TRAPS) { duke@435: acorn@949: // Classloaders that support parallelism, e.g. bootstrap classloader, acorn@949: // or all classloaders with UnsyncloadClass do not acquire lock here acorn@949: bool DoObjectLock = true; acorn@949: if (is_parallelCapable(class_loader)) { acorn@949: DoObjectLock = false; acorn@949: } acorn@949: acorn@949: // Make sure we are synchronized on the class loader before we proceed duke@435: Handle lockObject = compute_loader_lock_object(class_loader, THREAD); duke@435: check_loader_lock_contention(lockObject, THREAD); acorn@949: ObjectLocker ol(lockObject, THREAD, DoObjectLock); duke@435: duke@435: symbolHandle parsed_name; duke@435: duke@435: // Parse the stream. Note that we do this even though this klass might duke@435: // already be present in the SystemDictionary, otherwise we would not duke@435: // throw potential ClassFormatErrors. duke@435: // duke@435: // Note: "name" is updated. duke@435: // Further note: a placeholder will be added for this class when duke@435: // super classes are loaded (resolve_super_or_fail). We expect this duke@435: // to be called for all classes but java.lang.Object; and we preload duke@435: // java.lang.Object through resolve_or_fail, not this path. duke@435: duke@435: instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name, duke@435: class_loader, duke@435: protection_domain, duke@435: parsed_name, duke@435: THREAD); duke@435: duke@435: const char* pkg = "java/"; duke@435: if (!HAS_PENDING_EXCEPTION && duke@435: !class_loader.is_null() && duke@435: !parsed_name.is_null() && duke@435: !strncmp((const char*)parsed_name->bytes(), pkg, strlen(pkg))) { duke@435: // It is illegal to define classes in the "java." package from duke@435: // JVM_DefineClass or jni_DefineClass unless you're the bootclassloader duke@435: ResourceMark rm(THREAD); duke@435: char* name = parsed_name->as_C_string(); duke@435: char* index = strrchr(name, '/'); duke@435: *index = '\0'; // chop to just the package name duke@435: while ((index = strchr(name, '/')) != NULL) { duke@435: *index = '.'; // replace '/' with '.' in package name duke@435: } duke@435: const char* fmt = "Prohibited package name: %s"; duke@435: size_t len = strlen(fmt) + strlen(name); duke@435: char* message = NEW_RESOURCE_ARRAY(char, len); duke@435: jio_snprintf(message, len, fmt, name); duke@435: Exceptions::_throw_msg(THREAD_AND_LOCATION, duke@435: vmSymbols::java_lang_SecurityException(), message); duke@435: } duke@435: duke@435: if (!HAS_PENDING_EXCEPTION) { duke@435: assert(!parsed_name.is_null(), "Sanity"); duke@435: assert(class_name.is_null() || class_name() == parsed_name(), duke@435: "name mismatch"); duke@435: // Verification prevents us from creating names with dots in them, this duke@435: // asserts that that's the case. duke@435: assert(is_internal_format(parsed_name), duke@435: "external class name format used internally"); duke@435: duke@435: // Add class just loaded acorn@949: // If a class loader supports parallel classloading handle parallel define requests acorn@949: // find_or_define_instance_class may return a different instanceKlass acorn@949: if (is_parallelCapable(class_loader)) { acorn@949: k = find_or_define_instance_class(class_name, class_loader, k, THREAD); acorn@949: } else { acorn@949: define_instance_class(k, THREAD); acorn@949: } duke@435: } duke@435: duke@435: // If parsing the class file or define_instance_class failed, we duke@435: // need to remove the placeholder added on our behalf. But we duke@435: // must make sure parsed_name is valid first (it won't be if we had duke@435: // a format error before the class was parsed far enough to duke@435: // find the name). duke@435: if (HAS_PENDING_EXCEPTION && !parsed_name.is_null()) { duke@435: unsigned int p_hash = placeholders()->compute_hash(parsed_name, duke@435: class_loader); duke@435: int p_index = placeholders()->hash_to_index(p_hash); duke@435: { duke@435: MutexLocker mu(SystemDictionary_lock, THREAD); duke@435: placeholders()->find_and_remove(p_index, p_hash, parsed_name, class_loader, THREAD); duke@435: SystemDictionary_lock->notify_all(); duke@435: } duke@435: return NULL; duke@435: } duke@435: duke@435: // Make sure that we didn't leave a place holder in the duke@435: // SystemDictionary; this is only done on success duke@435: debug_only( { duke@435: if (!HAS_PENDING_EXCEPTION) { duke@435: assert(!parsed_name.is_null(), "parsed_name is still null?"); duke@435: symbolHandle h_name (THREAD, k->name()); duke@435: Handle h_loader (THREAD, k->class_loader()); duke@435: duke@435: MutexLocker mu(SystemDictionary_lock, THREAD); duke@435: duke@435: oop check = find_class_or_placeholder(parsed_name, class_loader); duke@435: assert(check == k(), "should be present in the dictionary"); duke@435: duke@435: oop check2 = find_class_or_placeholder(h_name, h_loader); duke@435: assert(check == check2, "name inconsistancy in SystemDictionary"); duke@435: } duke@435: } ); duke@435: duke@435: return k(); duke@435: } duke@435: duke@435: duke@435: void SystemDictionary::set_shared_dictionary(HashtableBucket* t, int length, duke@435: int number_of_entries) { duke@435: assert(length == _nof_buckets * sizeof(HashtableBucket), duke@435: "bad shared dictionary size."); duke@435: _shared_dictionary = new Dictionary(_nof_buckets, t, number_of_entries); duke@435: } duke@435: duke@435: duke@435: // If there is a shared dictionary, then find the entry for the duke@435: // given shared system class, if any. duke@435: duke@435: klassOop SystemDictionary::find_shared_class(symbolHandle class_name) { duke@435: if (shared_dictionary() != NULL) { duke@435: unsigned int d_hash = dictionary()->compute_hash(class_name, Handle()); duke@435: int d_index = dictionary()->hash_to_index(d_hash); duke@435: return shared_dictionary()->find_shared_class(d_index, d_hash, class_name); duke@435: } else { duke@435: return NULL; duke@435: } duke@435: } duke@435: duke@435: duke@435: // Load a class from the shared spaces (found through the shared system duke@435: // dictionary). Force the superclass and all interfaces to be loaded. duke@435: // Update the class definition to include sibling classes and no duke@435: // subclasses (yet). [Classes in the shared space are not part of the duke@435: // object hierarchy until loaded.] duke@435: duke@435: instanceKlassHandle SystemDictionary::load_shared_class( duke@435: symbolHandle class_name, Handle class_loader, TRAPS) { duke@435: instanceKlassHandle ik (THREAD, find_shared_class(class_name)); duke@435: return load_shared_class(ik, class_loader, THREAD); duke@435: } duke@435: duke@435: // Note well! Changes to this method may affect oop access order duke@435: // in the shared archive. Please take care to not make changes that duke@435: // adversely affect cold start time by changing the oop access order duke@435: // that is specified in dump.cpp MarkAndMoveOrderedReadOnly and duke@435: // MarkAndMoveOrderedReadWrite closures. duke@435: instanceKlassHandle SystemDictionary::load_shared_class( duke@435: instanceKlassHandle ik, Handle class_loader, TRAPS) { duke@435: assert(class_loader.is_null(), "non-null classloader for shared class?"); duke@435: if (ik.not_null()) { duke@435: instanceKlassHandle nh = instanceKlassHandle(); // null Handle duke@435: symbolHandle class_name(THREAD, ik->name()); duke@435: duke@435: // Found the class, now load the superclass and interfaces. If they duke@435: // are shared, add them to the main system dictionary and reset duke@435: // their hierarchy references (supers, subs, and interfaces). duke@435: duke@435: if (ik->super() != NULL) { duke@435: symbolHandle cn(THREAD, ik->super()->klass_part()->name()); duke@435: resolve_super_or_fail(class_name, cn, duke@435: class_loader, Handle(), true, CHECK_(nh)); duke@435: } duke@435: duke@435: objArrayHandle interfaces (THREAD, ik->local_interfaces()); duke@435: int num_interfaces = interfaces->length(); duke@435: for (int index = 0; index < num_interfaces; index++) { duke@435: klassOop k = klassOop(interfaces->obj_at(index)); duke@435: duke@435: // Note: can not use instanceKlass::cast here because duke@435: // interfaces' instanceKlass's C++ vtbls haven't been duke@435: // reinitialized yet (they will be once the interface classes duke@435: // are loaded) duke@435: symbolHandle name (THREAD, k->klass_part()->name()); duke@435: resolve_super_or_fail(class_name, name, class_loader, Handle(), false, CHECK_(nh)); duke@435: } duke@435: duke@435: // Adjust methods to recover missing data. They need addresses for duke@435: // interpreter entry points and their default native method address duke@435: // must be reset. duke@435: duke@435: // Updating methods must be done under a lock so multiple duke@435: // threads don't update these in parallel duke@435: // Shared classes are all currently loaded by the bootstrap duke@435: // classloader, so this will never cause a deadlock on duke@435: // a custom class loader lock. duke@435: duke@435: { duke@435: Handle lockObject = compute_loader_lock_object(class_loader, THREAD); duke@435: check_loader_lock_contention(lockObject, THREAD); duke@435: ObjectLocker ol(lockObject, THREAD, true); duke@435: duke@435: objArrayHandle methods (THREAD, ik->methods()); duke@435: int num_methods = methods->length(); duke@435: for (int index2 = 0; index2 < num_methods; ++index2) { duke@435: methodHandle m(THREAD, methodOop(methods->obj_at(index2))); duke@435: m()->link_method(m, CHECK_(nh)); duke@435: } duke@435: } duke@435: duke@435: if (TraceClassLoading) { duke@435: ResourceMark rm; duke@435: tty->print("[Loaded %s", ik->external_name()); duke@435: tty->print(" from shared objects file"); duke@435: tty->print_cr("]"); duke@435: } duke@435: // notify a class loaded from shared object duke@435: ClassLoadingService::notify_class_loaded(instanceKlass::cast(ik()), duke@435: true /* shared class */); duke@435: } duke@435: return ik; duke@435: } duke@435: duke@435: #ifdef KERNEL duke@435: // Some classes on the bootstrap class path haven't been installed on the duke@435: // system yet. Call the DownloadManager method to make them appear in the duke@435: // bootstrap class path and try again to load the named class. duke@435: // Note that with delegation class loaders all classes in another loader will duke@435: // first try to call this so it'd better be fast!! duke@435: static instanceKlassHandle download_and_retry_class_load( duke@435: symbolHandle class_name, duke@435: TRAPS) { duke@435: duke@435: klassOop dlm = SystemDictionary::sun_jkernel_DownloadManager_klass(); duke@435: instanceKlassHandle nk; duke@435: duke@435: // If download manager class isn't loaded just return. duke@435: if (dlm == NULL) return nk; duke@435: duke@435: { HandleMark hm(THREAD); duke@435: ResourceMark rm(THREAD); duke@435: Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nk)); duke@435: Handle class_string = java_lang_String::externalize_classname(s, CHECK_(nk)); duke@435: duke@435: // return value duke@435: JavaValue result(T_OBJECT); duke@435: duke@435: // Call the DownloadManager. We assume that it has a lock because duke@435: // multiple classes could be not found and downloaded at the same time. duke@435: // class sun.misc.DownloadManager; duke@435: // public static String getBootClassPathEntryForClass(String className); duke@435: JavaCalls::call_static(&result, duke@435: KlassHandle(THREAD, dlm), duke@435: vmSymbolHandles::getBootClassPathEntryForClass_name(), duke@435: vmSymbolHandles::string_string_signature(), duke@435: class_string, duke@435: CHECK_(nk)); duke@435: duke@435: // Get result.string and add to bootclasspath duke@435: assert(result.get_type() == T_OBJECT, "just checking"); duke@435: oop obj = (oop) result.get_jobject(); duke@435: if (obj == NULL) { return nk; } duke@435: coleenp@457: Handle h_obj(THREAD, obj); coleenp@457: char* new_class_name = java_lang_String::as_platform_dependent_str(h_obj, coleenp@457: CHECK_(nk)); duke@435: duke@435: // lock the loader duke@435: // we use this lock because JVMTI does. duke@435: Handle loader_lock(THREAD, SystemDictionary::system_loader_lock()); duke@435: duke@435: ObjectLocker ol(loader_lock, THREAD); duke@435: // add the file to the bootclasspath duke@435: ClassLoader::update_class_path_entry_list(new_class_name, true); duke@435: } // end HandleMark duke@435: duke@435: if (TraceClassLoading) { duke@435: ClassLoader::print_bootclasspath(); duke@435: } duke@435: return ClassLoader::load_classfile(class_name, CHECK_(nk)); duke@435: } duke@435: #endif // KERNEL duke@435: duke@435: duke@435: instanceKlassHandle SystemDictionary::load_instance_class(symbolHandle class_name, Handle class_loader, TRAPS) { duke@435: instanceKlassHandle nh = instanceKlassHandle(); // null Handle duke@435: if (class_loader.is_null()) { duke@435: // Search the shared system dictionary for classes preloaded into the duke@435: // shared spaces. duke@435: instanceKlassHandle k; duke@435: k = load_shared_class(class_name, class_loader, THREAD); duke@435: duke@435: if (k.is_null()) { duke@435: // Use VM class loader duke@435: k = ClassLoader::load_classfile(class_name, CHECK_(nh)); duke@435: } duke@435: duke@435: #ifdef KERNEL duke@435: // If the VM class loader has failed to load the class, call the duke@435: // DownloadManager class to make it magically appear on the classpath duke@435: // and try again. This is only configured with the Kernel VM. duke@435: if (k.is_null()) { duke@435: k = download_and_retry_class_load(class_name, CHECK_(nh)); duke@435: } duke@435: #endif // KERNEL duke@435: acorn@949: // find_or_define_instance_class may return a different instanceKlass duke@435: if (!k.is_null()) { duke@435: k = find_or_define_instance_class(class_name, class_loader, k, CHECK_(nh)); duke@435: } duke@435: return k; duke@435: } else { duke@435: // Use user specified class loader to load class. Call loadClass operation on class_loader. duke@435: ResourceMark rm(THREAD); duke@435: duke@435: Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nh)); duke@435: // Translate to external class name format, i.e., convert '/' chars to '.' duke@435: Handle string = java_lang_String::externalize_classname(s, CHECK_(nh)); duke@435: duke@435: JavaValue result(T_OBJECT); duke@435: duke@435: KlassHandle spec_klass (THREAD, SystemDictionary::classloader_klass()); duke@435: acorn@949: // Call public unsynchronized loadClass(String) directly for all class loaders acorn@949: // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will acorn@949: // acquire a class-name based lock rather than the class loader object lock. acorn@949: // JDK < 7 already acquire the class loader lock in loadClass(String, boolean), acorn@949: // so the call to loadClassInternal() was not required. acorn@949: // acorn@949: // UnsyncloadClass flag means both call loadClass(String) and do acorn@949: // not acquire the class loader lock even for class loaders that are acorn@949: // not parallelCapable. This was a risky transitional acorn@949: // flag for diagnostic purposes only. It is risky to call duke@435: // custom class loaders without synchronization. duke@435: // WARNING If a custom class loader does NOT synchronizer findClass, or callers of acorn@949: // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field. duke@435: // Do NOT assume this will be supported in future releases. acorn@949: // acorn@949: // Added MustCallLoadClassInternal in case we discover in the field acorn@949: // a customer that counts on this call acorn@949: if (MustCallLoadClassInternal && has_loadClassInternal()) { duke@435: JavaCalls::call_special(&result, duke@435: class_loader, duke@435: spec_klass, duke@435: vmSymbolHandles::loadClassInternal_name(), duke@435: vmSymbolHandles::string_class_signature(), duke@435: string, duke@435: CHECK_(nh)); duke@435: } else { duke@435: JavaCalls::call_virtual(&result, duke@435: class_loader, duke@435: spec_klass, duke@435: vmSymbolHandles::loadClass_name(), duke@435: vmSymbolHandles::string_class_signature(), duke@435: string, duke@435: CHECK_(nh)); duke@435: } duke@435: duke@435: assert(result.get_type() == T_OBJECT, "just checking"); duke@435: oop obj = (oop) result.get_jobject(); duke@435: duke@435: // Primitive classes return null since forName() can not be duke@435: // used to obtain any of the Class objects representing primitives or void duke@435: if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) { duke@435: instanceKlassHandle k = duke@435: instanceKlassHandle(THREAD, java_lang_Class::as_klassOop(obj)); duke@435: // For user defined Java class loaders, check that the name returned is duke@435: // the same as that requested. This check is done for the bootstrap duke@435: // loader when parsing the class file. duke@435: if (class_name() == k->name()) { duke@435: return k; duke@435: } duke@435: } duke@435: // Class is not found or has the wrong name, return NULL duke@435: return nh; duke@435: } duke@435: } duke@435: duke@435: void SystemDictionary::define_instance_class(instanceKlassHandle k, TRAPS) { duke@435: duke@435: Handle class_loader_h(THREAD, k->class_loader()); duke@435: acorn@949: // for bootstrap and other parallel classloaders don't acquire lock, acorn@949: // use placeholder token acorn@949: // If a parallelCapable class loader calls define_instance_class instead of acorn@949: // find_or_define_instance_class to get here, we have a timing acorn@949: // hole with systemDictionary updates and check_constraints acorn@949: if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) { duke@435: assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, duke@435: compute_loader_lock_object(class_loader_h, THREAD)), duke@435: "define called without lock"); duke@435: } duke@435: duke@435: // Check class-loading constraints. Throw exception if violation is detected. duke@435: // Grabs and releases SystemDictionary_lock duke@435: // The check_constraints/find_class call and update_dictionary sequence duke@435: // must be "atomic" for a specific class/classloader pair so we never duke@435: // define two different instanceKlasses for that class/classloader pair. duke@435: // Existing classloaders will call define_instance_class with the duke@435: // classloader lock held duke@435: // Parallel classloaders will call find_or_define_instance_class duke@435: // which will require a token to perform the define class duke@435: symbolHandle name_h(THREAD, k->name()); duke@435: unsigned int d_hash = dictionary()->compute_hash(name_h, class_loader_h); duke@435: int d_index = dictionary()->hash_to_index(d_hash); duke@435: check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK); duke@435: duke@435: // Register class just loaded with class loader (placed in Vector) duke@435: // Note we do this before updating the dictionary, as this can duke@435: // fail with an OutOfMemoryError (if it does, we will *not* put this duke@435: // class in the dictionary and will not update the class hierarchy). duke@435: if (k->class_loader() != NULL) { duke@435: methodHandle m(THREAD, Universe::loader_addClass_method()); duke@435: JavaValue result(T_VOID); duke@435: JavaCallArguments args(class_loader_h); duke@435: args.push_oop(Handle(THREAD, k->java_mirror())); duke@435: JavaCalls::call(&result, m, &args, CHECK); duke@435: } duke@435: duke@435: // Add the new class. We need recompile lock during update of CHA. duke@435: { duke@435: unsigned int p_hash = placeholders()->compute_hash(name_h, class_loader_h); duke@435: int p_index = placeholders()->hash_to_index(p_hash); duke@435: duke@435: MutexLocker mu_r(Compile_lock, THREAD); duke@435: duke@435: // Add to class hierarchy, initialize vtables, and do possible duke@435: // deoptimizations. duke@435: add_to_hierarchy(k, CHECK); // No exception, but can block duke@435: duke@435: // Add to systemDictionary - so other classes can see it. duke@435: // Grabs and releases SystemDictionary_lock duke@435: update_dictionary(d_index, d_hash, p_index, p_hash, duke@435: k, class_loader_h, THREAD); duke@435: } duke@435: k->eager_initialize(THREAD); duke@435: duke@435: // notify jvmti duke@435: if (JvmtiExport::should_post_class_load()) { duke@435: assert(THREAD->is_Java_thread(), "thread->is_Java_thread()"); duke@435: JvmtiExport::post_class_load((JavaThread *) THREAD, k()); duke@435: duke@435: } duke@435: } duke@435: duke@435: // Support parallel classloading duke@435: // Initial implementation for bootstrap classloader duke@435: // For custom class loaders that support parallel classloading, acorn@949: // With AllowParallelDefine flag==true, in case they do not synchronize around acorn@949: // FindLoadedClass/DefineClass, calls, we check for parallel duke@435: // loading for them, wait if a defineClass is in progress duke@435: // and return the initial requestor's results acorn@949: // With AllowParallelDefine flag==false, call through to define_instance_class acorn@949: // which will throw LinkageError: duplicate class definition. duke@435: // For better performance, the class loaders should synchronize acorn@949: // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they duke@435: // potentially waste time reading and parsing the bytestream. duke@435: // Note: VM callers should ensure consistency of k/class_name,class_loader duke@435: instanceKlassHandle SystemDictionary::find_or_define_instance_class(symbolHandle class_name, Handle class_loader, instanceKlassHandle k, TRAPS) { duke@435: duke@435: instanceKlassHandle nh = instanceKlassHandle(); // null Handle acorn@950: symbolHandle name_h(THREAD, k->name()); // passed in class_name may be null duke@435: acorn@950: unsigned int d_hash = dictionary()->compute_hash(name_h, class_loader); duke@435: int d_index = dictionary()->hash_to_index(d_hash); duke@435: duke@435: // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS acorn@950: unsigned int p_hash = placeholders()->compute_hash(name_h, class_loader); duke@435: int p_index = placeholders()->hash_to_index(p_hash); duke@435: PlaceholderEntry* probe; duke@435: duke@435: { duke@435: MutexLocker mu(SystemDictionary_lock, THREAD); duke@435: // First check if class already defined acorn@950: klassOop check = find_class(d_index, d_hash, name_h, class_loader); duke@435: if (check != NULL) { duke@435: return(instanceKlassHandle(THREAD, check)); duke@435: } duke@435: duke@435: // Acquire define token for this class/classloader duke@435: symbolHandle nullsymbolHandle; acorn@950: probe = placeholders()->find_and_add(p_index, p_hash, name_h, class_loader, PlaceholderTable::DEFINE_CLASS, nullsymbolHandle, THREAD); acorn@949: // Wait if another thread defining in parallel acorn@949: // All threads wait - even those that will throw duplicate class: otherwise acorn@949: // caller is surprised by LinkageError: duplicate, but findLoadedClass fails acorn@949: // if other thread has not finished updating dictionary acorn@949: while (probe->definer() != NULL) { acorn@949: SystemDictionary_lock->wait(); acorn@949: } acorn@949: // Only special cases allow parallel defines and can use other thread's results acorn@949: // Other cases fall through, and may run into duplicate defines acorn@949: // caught by finding an entry in the SystemDictionary acorn@949: if ((UnsyncloadClass || AllowParallelDefineClass) && (probe->instanceKlass() != NULL)) { jrose@866: probe->remove_seen_thread(THREAD, PlaceholderTable::DEFINE_CLASS); acorn@950: placeholders()->find_and_remove(p_index, p_hash, name_h, class_loader, THREAD); acorn@949: SystemDictionary_lock->notify_all(); jrose@866: #ifdef ASSERT acorn@950: klassOop check = find_class(d_index, d_hash, name_h, class_loader); acorn@949: assert(check != NULL, "definer missed recording success"); jrose@866: #endif acorn@949: return(instanceKlassHandle(THREAD, probe->instanceKlass())); acorn@949: } else { acorn@949: // This thread will define the class (even if earlier thread tried and had an error) duke@435: probe->set_definer(THREAD); duke@435: } duke@435: } duke@435: duke@435: define_instance_class(k, THREAD); duke@435: duke@435: Handle linkage_exception = Handle(); // null handle duke@435: duke@435: // definer must notify any waiting threads duke@435: { duke@435: MutexLocker mu(SystemDictionary_lock, THREAD); acorn@950: PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, class_loader); duke@435: assert(probe != NULL, "DEFINE_CLASS placeholder lost?"); duke@435: if (probe != NULL) { duke@435: if (HAS_PENDING_EXCEPTION) { duke@435: linkage_exception = Handle(THREAD,PENDING_EXCEPTION); duke@435: CLEAR_PENDING_EXCEPTION; duke@435: } else { duke@435: probe->set_instanceKlass(k()); duke@435: } duke@435: probe->set_definer(NULL); duke@435: probe->remove_seen_thread(THREAD, PlaceholderTable::DEFINE_CLASS); acorn@950: placeholders()->find_and_remove(p_index, p_hash, name_h, class_loader, THREAD); duke@435: SystemDictionary_lock->notify_all(); duke@435: } duke@435: } duke@435: duke@435: // Can't throw exception while holding lock due to rank ordering duke@435: if (linkage_exception() != NULL) { duke@435: THROW_OOP_(linkage_exception(), nh); // throws exception and returns duke@435: } duke@435: duke@435: return k; duke@435: } duke@435: Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) { duke@435: // If class_loader is NULL we synchronize on _system_loader_lock_obj duke@435: if (class_loader.is_null()) { duke@435: return Handle(THREAD, _system_loader_lock_obj); duke@435: } else { duke@435: return class_loader; duke@435: } duke@435: } duke@435: duke@435: // This method is added to check how often we have to wait to grab loader duke@435: // lock. The results are being recorded in the performance counters defined in duke@435: // ClassLoader::_sync_systemLoaderLockContentionRate and duke@435: // ClassLoader::_sync_nonSystemLoaderLockConteionRate. duke@435: void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) { duke@435: if (!UsePerfData) { duke@435: return; duke@435: } duke@435: duke@435: assert(!loader_lock.is_null(), "NULL lock object"); duke@435: duke@435: if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock) duke@435: == ObjectSynchronizer::owner_other) { duke@435: // contention will likely happen, so increment the corresponding duke@435: // contention counter. duke@435: if (loader_lock() == _system_loader_lock_obj) { duke@435: ClassLoader::sync_systemLoaderLockContentionRate()->inc(); duke@435: } else { duke@435: ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc(); duke@435: } duke@435: } duke@435: } duke@435: duke@435: // ---------------------------------------------------------------------------- duke@435: // Lookup duke@435: duke@435: klassOop SystemDictionary::find_class(int index, unsigned int hash, duke@435: symbolHandle class_name, duke@435: Handle class_loader) { duke@435: assert_locked_or_safepoint(SystemDictionary_lock); duke@435: assert (index == dictionary()->index_for(class_name, class_loader), duke@435: "incorrect index?"); duke@435: duke@435: klassOop k = dictionary()->find_class(index, hash, class_name, class_loader); duke@435: return k; duke@435: } duke@435: duke@435: duke@435: // Basic find on classes in the midst of being loaded duke@435: symbolOop SystemDictionary::find_placeholder(int index, unsigned int hash, duke@435: symbolHandle class_name, duke@435: Handle class_loader) { duke@435: assert_locked_or_safepoint(SystemDictionary_lock); duke@435: duke@435: return placeholders()->find_entry(index, hash, class_name, class_loader); duke@435: } duke@435: duke@435: duke@435: // Used for assertions and verification only duke@435: oop SystemDictionary::find_class_or_placeholder(symbolHandle class_name, duke@435: Handle class_loader) { duke@435: #ifndef ASSERT duke@435: guarantee(VerifyBeforeGC || duke@435: VerifyDuringGC || duke@435: VerifyBeforeExit || duke@435: VerifyAfterGC, "too expensive"); duke@435: #endif duke@435: assert_locked_or_safepoint(SystemDictionary_lock); duke@435: symbolOop class_name_ = class_name(); duke@435: oop class_loader_ = class_loader(); duke@435: duke@435: // First look in the loaded class array duke@435: unsigned int d_hash = dictionary()->compute_hash(class_name, class_loader); duke@435: int d_index = dictionary()->hash_to_index(d_hash); duke@435: oop lookup = find_class(d_index, d_hash, class_name, class_loader); duke@435: duke@435: if (lookup == NULL) { duke@435: // Next try the placeholders duke@435: unsigned int p_hash = placeholders()->compute_hash(class_name,class_loader); duke@435: int p_index = placeholders()->hash_to_index(p_hash); duke@435: lookup = find_placeholder(p_index, p_hash, class_name, class_loader); duke@435: } duke@435: duke@435: return lookup; duke@435: } duke@435: duke@435: duke@435: // Get the next class in the diictionary. duke@435: klassOop SystemDictionary::try_get_next_class() { duke@435: return dictionary()->try_get_next_class(); duke@435: } duke@435: duke@435: duke@435: // ---------------------------------------------------------------------------- duke@435: // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock duke@435: // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in duke@435: // before a new class is used. duke@435: duke@435: void SystemDictionary::add_to_hierarchy(instanceKlassHandle k, TRAPS) { duke@435: assert(k.not_null(), "just checking"); duke@435: // Link into hierachy. Make sure the vtables are initialized before linking into duke@435: k->append_to_sibling_list(); // add to superklass/sibling list duke@435: k->process_interfaces(THREAD); // handle all "implements" declarations duke@435: k->set_init_state(instanceKlass::loaded); duke@435: // Now flush all code that depended on old class hierarchy. duke@435: // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97) duke@435: // Also, first reinitialize vtable because it may have gotten out of synch duke@435: // while the new class wasn't connected to the class hierarchy. duke@435: Universe::flush_dependents_on(k); duke@435: } duke@435: duke@435: duke@435: // ---------------------------------------------------------------------------- duke@435: // GC support duke@435: duke@435: // Following roots during mark-sweep is separated in two phases. duke@435: // duke@435: // The first phase follows preloaded classes and all other system duke@435: // classes, since these will never get unloaded anyway. duke@435: // duke@435: // The second phase removes (unloads) unreachable classes from the duke@435: // system dictionary and follows the remaining classes' contents. duke@435: duke@435: void SystemDictionary::always_strong_oops_do(OopClosure* blk) { duke@435: // Follow preloaded classes/mirrors and system loader object duke@435: blk->do_oop(&_java_system_loader); duke@435: preloaded_oops_do(blk); duke@435: always_strong_classes_do(blk); duke@435: } duke@435: duke@435: duke@435: void SystemDictionary::always_strong_classes_do(OopClosure* blk) { duke@435: // Follow all system classes and temporary placeholders in dictionary duke@435: dictionary()->always_strong_classes_do(blk); duke@435: duke@435: // Placeholders. These are *always* strong roots, as they duke@435: // represent classes we're actively loading. duke@435: placeholders_do(blk); duke@435: duke@435: // Loader constraints. We must keep the symbolOop used in the name alive. duke@435: constraints()->always_strong_classes_do(blk); duke@435: duke@435: // Resolution errors keep the symbolOop for the error alive duke@435: resolution_errors()->always_strong_classes_do(blk); duke@435: } duke@435: duke@435: duke@435: void SystemDictionary::placeholders_do(OopClosure* blk) { duke@435: placeholders()->oops_do(blk); duke@435: } duke@435: duke@435: duke@435: bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive) { duke@435: bool result = dictionary()->do_unloading(is_alive); duke@435: constraints()->purge_loader_constraints(is_alive); duke@435: resolution_errors()->purge_resolution_errors(is_alive); duke@435: return result; duke@435: } duke@435: duke@435: duke@435: // The mirrors are scanned by shared_oops_do() which is duke@435: // not called by oops_do(). In order to process oops in duke@435: // a necessary order, shared_oops_do() is call by duke@435: // Universe::oops_do(). duke@435: void SystemDictionary::oops_do(OopClosure* f) { duke@435: // Adjust preloaded classes and system loader object duke@435: f->do_oop(&_java_system_loader); duke@435: preloaded_oops_do(f); duke@435: duke@435: lazily_loaded_oops_do(f); duke@435: duke@435: // Adjust dictionary duke@435: dictionary()->oops_do(f); duke@435: duke@435: // Partially loaded classes duke@435: placeholders()->oops_do(f); duke@435: duke@435: // Adjust constraint table duke@435: constraints()->oops_do(f); duke@435: duke@435: // Adjust resolution error table duke@435: resolution_errors()->oops_do(f); duke@435: } duke@435: duke@435: duke@435: void SystemDictionary::preloaded_oops_do(OopClosure* f) { jrose@567: f->do_oop((oop*) &wk_klass_name_limits[0]); jrose@567: f->do_oop((oop*) &wk_klass_name_limits[1]); duke@435: jrose@567: for (int k = (int)FIRST_WKID; k < (int)WKID_LIMIT; k++) { jrose@567: f->do_oop((oop*) &_well_known_klasses[k]); jrose@567: } duke@435: duke@435: { duke@435: for (int i = 0; i < T_VOID+1; i++) { duke@435: if (_box_klasses[i] != NULL) { duke@435: assert(i >= T_BOOLEAN, "checking"); duke@435: f->do_oop((oop*) &_box_klasses[i]); duke@435: } duke@435: } duke@435: } duke@435: duke@435: // The basic type mirrors would have already been processed in duke@435: // Universe::oops_do(), via a call to shared_oops_do(), so should duke@435: // not be processed again. duke@435: duke@435: f->do_oop((oop*) &_system_loader_lock_obj); duke@435: FilteredFieldsMap::klasses_oops_do(f); duke@435: } duke@435: duke@435: void SystemDictionary::lazily_loaded_oops_do(OopClosure* f) { duke@435: f->do_oop((oop*) &_abstract_ownable_synchronizer_klass); duke@435: } duke@435: duke@435: // Just the classes from defining class loaders duke@435: // Don't iterate over placeholders duke@435: void SystemDictionary::classes_do(void f(klassOop)) { duke@435: dictionary()->classes_do(f); duke@435: } duke@435: duke@435: // Added for initialize_itable_for_klass duke@435: // Just the classes from defining class loaders duke@435: // Don't iterate over placeholders duke@435: void SystemDictionary::classes_do(void f(klassOop, TRAPS), TRAPS) { duke@435: dictionary()->classes_do(f, CHECK); duke@435: } duke@435: duke@435: // All classes, and their class loaders duke@435: // Don't iterate over placeholders duke@435: void SystemDictionary::classes_do(void f(klassOop, oop)) { duke@435: dictionary()->classes_do(f); duke@435: } duke@435: duke@435: // All classes, and their class loaders duke@435: // (added for helpers that use HandleMarks and ResourceMarks) duke@435: // Don't iterate over placeholders duke@435: void SystemDictionary::classes_do(void f(klassOop, oop, TRAPS), TRAPS) { duke@435: dictionary()->classes_do(f, CHECK); duke@435: } duke@435: duke@435: void SystemDictionary::placeholders_do(void f(symbolOop, oop)) { duke@435: placeholders()->entries_do(f); duke@435: } duke@435: duke@435: void SystemDictionary::methods_do(void f(methodOop)) { duke@435: dictionary()->methods_do(f); duke@435: } duke@435: duke@435: // ---------------------------------------------------------------------------- duke@435: // Lazily load klasses duke@435: duke@435: void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) { duke@435: assert(JDK_Version::is_gte_jdk16x_version(), "Must be JDK 1.6 or later"); duke@435: duke@435: // if multiple threads calling this function, only one thread will load duke@435: // the class. The other threads will find the loaded version once the duke@435: // class is loaded. duke@435: klassOop aos = _abstract_ownable_synchronizer_klass; duke@435: if (aos == NULL) { duke@435: klassOop k = resolve_or_fail(vmSymbolHandles::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK); duke@435: // Force a fence to prevent any read before the write completes duke@435: OrderAccess::fence(); duke@435: _abstract_ownable_synchronizer_klass = k; duke@435: } duke@435: } duke@435: duke@435: // ---------------------------------------------------------------------------- duke@435: // Initialization duke@435: duke@435: void SystemDictionary::initialize(TRAPS) { duke@435: // Allocate arrays duke@435: assert(dictionary() == NULL, duke@435: "SystemDictionary should only be initialized once"); duke@435: _dictionary = new Dictionary(_nof_buckets); duke@435: _placeholders = new PlaceholderTable(_nof_buckets); duke@435: _number_of_modifications = 0; duke@435: _loader_constraints = new LoaderConstraintTable(_loader_constraint_size); duke@435: _resolution_errors = new ResolutionErrorTable(_resolution_error_size); duke@435: duke@435: // Allocate private object used as system class loader lock duke@435: _system_loader_lock_obj = oopFactory::new_system_objArray(0, CHECK); duke@435: // Initialize basic classes duke@435: initialize_preloaded_classes(CHECK); duke@435: } duke@435: jrose@567: // Compact table of directions on the initialization of klasses: jrose@567: static const short wk_init_info[] = { jrose@567: #define WK_KLASS_INIT_INFO(name, symbol, option) \ jrose@567: ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \ jrose@567: << SystemDictionary::CEIL_LG_OPTION_LIMIT) \ jrose@567: | (int)SystemDictionary::option ), jrose@567: WK_KLASSES_DO(WK_KLASS_INIT_INFO) jrose@567: #undef WK_KLASS_INIT_INFO jrose@567: 0 jrose@567: }; jrose@567: jrose@567: bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) { jrose@567: assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob"); jrose@567: int info = wk_init_info[id - FIRST_WKID]; jrose@567: int sid = (info >> CEIL_LG_OPTION_LIMIT); jrose@567: symbolHandle symbol = vmSymbolHandles::symbol_handle_at((vmSymbols::SID)sid); jrose@567: klassOop* klassp = &_well_known_klasses[id]; jrose@567: bool must_load = (init_opt < SystemDictionary::Opt); jrose@567: bool try_load = true; jrose@567: if (init_opt == SystemDictionary::Opt_Kernel) { jrose@567: #ifndef KERNEL jrose@567: try_load = false; jrose@567: #endif //KERNEL jrose@567: } jrose@567: if ((*klassp) == NULL && try_load) { jrose@567: if (must_load) { jrose@567: (*klassp) = resolve_or_fail(symbol, true, CHECK_0); // load required class jrose@567: } else { jrose@567: (*klassp) = resolve_or_null(symbol, CHECK_0); // load optional klass jrose@567: } jrose@567: } jrose@567: return ((*klassp) != NULL); jrose@567: } jrose@567: jrose@567: void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) { jrose@567: assert((int)start_id <= (int)limit_id, "IDs are out of order!"); jrose@567: for (int id = (int)start_id; id < (int)limit_id; id++) { jrose@567: assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob"); jrose@567: int info = wk_init_info[id - FIRST_WKID]; jrose@567: int sid = (info >> CEIL_LG_OPTION_LIMIT); jrose@567: int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT)); jrose@567: jrose@567: initialize_wk_klass((WKID)id, opt, CHECK); jrose@567: jrose@567: // Update limits, so find_well_known_klass can be very fast: jrose@567: symbolOop s = vmSymbols::symbol_at((vmSymbols::SID)sid); jrose@567: if (wk_klass_name_limits[1] == NULL) { jrose@567: wk_klass_name_limits[0] = wk_klass_name_limits[1] = s; jrose@567: } else if (wk_klass_name_limits[1] < s) { jrose@567: wk_klass_name_limits[1] = s; jrose@567: } else if (wk_klass_name_limits[0] > s) { jrose@567: wk_klass_name_limits[0] = s; jrose@567: } jrose@567: } jrose@567: } jrose@567: duke@435: duke@435: void SystemDictionary::initialize_preloaded_classes(TRAPS) { jrose@567: assert(WK_KLASS(object_klass) == NULL, "preloaded classes should only be initialized once"); duke@435: // Preload commonly used klasses jrose@567: WKID scan = FIRST_WKID; jrose@567: // first do Object, String, Class jrose@567: initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(class_klass), scan, CHECK); jrose@567: jrose@567: debug_only(instanceKlass::verify_class_klass_nonstatic_oop_maps(WK_KLASS(class_klass))); jrose@567: duke@435: // Fixup mirrors for classes loaded before java.lang.Class. duke@435: // These calls iterate over the objects currently in the perm gen duke@435: // so calling them at this point is matters (not before when there duke@435: // are fewer objects and not later after there are more objects duke@435: // in the perm gen. duke@435: Universe::initialize_basic_type_mirrors(CHECK); duke@435: Universe::fixup_mirrors(CHECK); duke@435: jrose@567: // do a bunch more: jrose@567: initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(reference_klass), scan, CHECK); duke@435: duke@435: // Preload ref klasses and set reference types jrose@567: instanceKlass::cast(WK_KLASS(reference_klass))->set_reference_type(REF_OTHER); jrose@567: instanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(reference_klass)); duke@435: jrose@567: initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(phantom_reference_klass), scan, CHECK); jrose@567: instanceKlass::cast(WK_KLASS(soft_reference_klass))->set_reference_type(REF_SOFT); jrose@567: instanceKlass::cast(WK_KLASS(weak_reference_klass))->set_reference_type(REF_WEAK); jrose@567: instanceKlass::cast(WK_KLASS(final_reference_klass))->set_reference_type(REF_FINAL); jrose@567: instanceKlass::cast(WK_KLASS(phantom_reference_klass))->set_reference_type(REF_PHANTOM); duke@435: jrose@567: initialize_wk_klasses_until(WKID_LIMIT, scan, CHECK); duke@435: jrose@567: _box_klasses[T_BOOLEAN] = WK_KLASS(boolean_klass); jrose@567: _box_klasses[T_CHAR] = WK_KLASS(char_klass); jrose@567: _box_klasses[T_FLOAT] = WK_KLASS(float_klass); jrose@567: _box_klasses[T_DOUBLE] = WK_KLASS(double_klass); jrose@567: _box_klasses[T_BYTE] = WK_KLASS(byte_klass); jrose@567: _box_klasses[T_SHORT] = WK_KLASS(short_klass); jrose@567: _box_klasses[T_INT] = WK_KLASS(int_klass); jrose@567: _box_klasses[T_LONG] = WK_KLASS(long_klass); jrose@567: //_box_klasses[T_OBJECT] = WK_KLASS(object_klass); jrose@567: //_box_klasses[T_ARRAY] = WK_KLASS(object_klass); duke@435: duke@435: #ifdef KERNEL jrose@567: if (sun_jkernel_DownloadManager_klass() == NULL) { duke@435: warning("Cannot find sun/jkernel/DownloadManager"); duke@435: } duke@435: #endif // KERNEL acorn@949: duke@435: { // Compute whether we should use loadClass or loadClassInternal when loading classes. duke@435: methodOop method = instanceKlass::cast(classloader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature()); duke@435: _has_loadClassInternal = (method != NULL); duke@435: } duke@435: { // Compute whether we should use checkPackageAccess or NOT duke@435: methodOop method = instanceKlass::cast(classloader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature()); duke@435: _has_checkPackageAccess = (method != NULL); duke@435: } duke@435: } duke@435: duke@435: // Tells if a given klass is a box (wrapper class, such as java.lang.Integer). duke@435: // If so, returns the basic type it holds. If not, returns T_OBJECT. duke@435: BasicType SystemDictionary::box_klass_type(klassOop k) { duke@435: assert(k != NULL, ""); duke@435: for (int i = T_BOOLEAN; i < T_VOID+1; i++) { duke@435: if (_box_klasses[i] == k) duke@435: return (BasicType)i; duke@435: } duke@435: return T_OBJECT; duke@435: } duke@435: duke@435: // Constraints on class loaders. The details of the algorithm can be duke@435: // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java duke@435: // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is duke@435: // that the system dictionary needs to maintain a set of contraints that duke@435: // must be satisfied by all classes in the dictionary. duke@435: // if defining is true, then LinkageError if already in systemDictionary duke@435: // if initiating loader, then ok if instanceKlass matches existing entry duke@435: duke@435: void SystemDictionary::check_constraints(int d_index, unsigned int d_hash, duke@435: instanceKlassHandle k, duke@435: Handle class_loader, bool defining, duke@435: TRAPS) { duke@435: const char *linkage_error = NULL; duke@435: { duke@435: symbolHandle name (THREAD, k->name()); duke@435: MutexLocker mu(SystemDictionary_lock, THREAD); duke@435: duke@435: klassOop check = find_class(d_index, d_hash, name, class_loader); duke@435: if (check != (klassOop)NULL) { duke@435: // if different instanceKlass - duplicate class definition, duke@435: // else - ok, class loaded by a different thread in parallel, duke@435: // we should only have found it if it was done loading and ok to use duke@435: // system dictionary only holds instance classes, placeholders duke@435: // also holds array classes duke@435: duke@435: assert(check->klass_part()->oop_is_instance(), "noninstance in systemdictionary"); duke@435: if ((defining == true) || (k() != check)) { duke@435: linkage_error = "loader (instance of %s): attempted duplicate class " duke@435: "definition for name: \"%s\""; duke@435: } else { duke@435: return; duke@435: } duke@435: } duke@435: duke@435: #ifdef ASSERT duke@435: unsigned int p_hash = placeholders()->compute_hash(name, class_loader); duke@435: int p_index = placeholders()->hash_to_index(p_hash); duke@435: symbolOop ph_check = find_placeholder(p_index, p_hash, name, class_loader); duke@435: assert(ph_check == NULL || ph_check == name(), "invalid symbol"); duke@435: #endif duke@435: duke@435: if (linkage_error == NULL) { duke@435: if (constraints()->check_or_update(k, class_loader, name) == false) { duke@435: linkage_error = "loader constraint violation: loader (instance of %s)" duke@435: " previously initiated loading for a different type with name \"%s\""; duke@435: } duke@435: } duke@435: } duke@435: duke@435: // Throw error now if needed (cannot throw while holding duke@435: // SystemDictionary_lock because of rank ordering) duke@435: duke@435: if (linkage_error) { duke@435: ResourceMark rm(THREAD); duke@435: const char* class_loader_name = loader_name(class_loader()); duke@435: char* type_name = k->name()->as_C_string(); duke@435: size_t buflen = strlen(linkage_error) + strlen(class_loader_name) + duke@435: strlen(type_name); duke@435: char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen); duke@435: jio_snprintf(buf, buflen, linkage_error, class_loader_name, type_name); duke@435: THROW_MSG(vmSymbols::java_lang_LinkageError(), buf); duke@435: } duke@435: } duke@435: duke@435: duke@435: // Update system dictionary - done after check_constraint and add_to_hierachy duke@435: // have been called. duke@435: void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash, duke@435: int p_index, unsigned int p_hash, duke@435: instanceKlassHandle k, duke@435: Handle class_loader, duke@435: TRAPS) { duke@435: // Compile_lock prevents systemDictionary updates during compilations duke@435: assert_locked_or_safepoint(Compile_lock); duke@435: symbolHandle name (THREAD, k->name()); duke@435: duke@435: { duke@435: MutexLocker mu1(SystemDictionary_lock, THREAD); duke@435: duke@435: // See whether biased locking is enabled and if so set it for this duke@435: // klass. duke@435: // Note that this must be done past the last potential blocking duke@435: // point / safepoint. We enable biased locking lazily using a duke@435: // VM_Operation to iterate the SystemDictionary and installing the duke@435: // biasable mark word into each instanceKlass's prototype header. duke@435: // To avoid race conditions where we accidentally miss enabling the duke@435: // optimization for one class in the process of being added to the duke@435: // dictionary, we must not safepoint after the test of duke@435: // BiasedLocking::enabled(). duke@435: if (UseBiasedLocking && BiasedLocking::enabled()) { duke@435: // Set biased locking bit for all loaded classes; it will be duke@435: // cleared if revocation occurs too often for this type duke@435: // NOTE that we must only do this when the class is initally duke@435: // defined, not each time it is referenced from a new class loader duke@435: if (k->class_loader() == class_loader()) { duke@435: k->set_prototype_header(markOopDesc::biased_locking_prototype()); duke@435: } duke@435: } duke@435: duke@435: // Check for a placeholder. If there, remove it and make a duke@435: // new system dictionary entry. duke@435: placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD); duke@435: klassOop sd_check = find_class(d_index, d_hash, name, class_loader); duke@435: if (sd_check == NULL) { duke@435: dictionary()->add_klass(name, class_loader, k); duke@435: notice_modification(); duke@435: } duke@435: #ifdef ASSERT duke@435: sd_check = find_class(d_index, d_hash, name, class_loader); duke@435: assert (sd_check != NULL, "should have entry in system dictionary"); duke@435: // Changed to allow PH to remain to complete class circularity checking duke@435: // while only one thread can define a class at one time, multiple duke@435: // classes can resolve the superclass for a class at one time, duke@435: // and the placeholder is used to track that duke@435: // symbolOop ph_check = find_placeholder(p_index, p_hash, name, class_loader); duke@435: // assert (ph_check == NULL, "should not have a placeholder entry"); duke@435: #endif duke@435: SystemDictionary_lock->notify_all(); duke@435: } duke@435: } duke@435: duke@435: duke@435: klassOop SystemDictionary::find_constrained_instance_or_array_klass( duke@435: symbolHandle class_name, Handle class_loader, TRAPS) { duke@435: duke@435: // First see if it has been loaded directly. duke@435: // Force the protection domain to be null. (This removes protection checks.) duke@435: Handle no_protection_domain; duke@435: klassOop klass = find_instance_or_array_klass(class_name, class_loader, duke@435: no_protection_domain, CHECK_NULL); duke@435: if (klass != NULL) duke@435: return klass; duke@435: duke@435: // Now look to see if it has been loaded elsewhere, and is subject to duke@435: // a loader constraint that would require this loader to return the duke@435: // klass that is already loaded. duke@435: if (FieldType::is_array(class_name())) { duke@435: // Array classes are hard because their klassOops are not kept in the duke@435: // constraint table. The array klass may be constrained, but the elem class duke@435: // may not be. duke@435: jint dimension; duke@435: symbolOop object_key; duke@435: BasicType t = FieldType::get_array_info(class_name(), &dimension, duke@435: &object_key, CHECK_(NULL)); duke@435: if (t != T_OBJECT) { duke@435: klass = Universe::typeArrayKlassObj(t); duke@435: } else { duke@435: symbolHandle elem_name(THREAD, object_key); duke@435: MutexLocker mu(SystemDictionary_lock, THREAD); duke@435: klass = constraints()->find_constrained_elem_klass(class_name, elem_name, class_loader, THREAD); duke@435: } duke@435: if (klass != NULL) { duke@435: klass = Klass::cast(klass)->array_klass_or_null(dimension); duke@435: } duke@435: } else { duke@435: MutexLocker mu(SystemDictionary_lock, THREAD); duke@435: // Non-array classes are easy: simply check the constraint table. duke@435: klass = constraints()->find_constrained_klass(class_name, class_loader); duke@435: } duke@435: duke@435: return klass; duke@435: } duke@435: duke@435: duke@435: bool SystemDictionary::add_loader_constraint(symbolHandle class_name, duke@435: Handle class_loader1, duke@435: Handle class_loader2, duke@435: Thread* THREAD) { duke@435: unsigned int d_hash1 = dictionary()->compute_hash(class_name, class_loader1); duke@435: int d_index1 = dictionary()->hash_to_index(d_hash1); duke@435: duke@435: unsigned int d_hash2 = dictionary()->compute_hash(class_name, class_loader2); duke@435: int d_index2 = dictionary()->hash_to_index(d_hash2); duke@435: duke@435: { duke@435: MutexLocker mu_s(SystemDictionary_lock, THREAD); duke@435: duke@435: // Better never do a GC while we're holding these oops duke@435: No_Safepoint_Verifier nosafepoint; duke@435: duke@435: klassOop klass1 = find_class(d_index1, d_hash1, class_name, class_loader1); duke@435: klassOop klass2 = find_class(d_index2, d_hash2, class_name, class_loader2); duke@435: return constraints()->add_entry(class_name, klass1, class_loader1, duke@435: klass2, class_loader2); duke@435: } duke@435: } duke@435: duke@435: // Add entry to resolution error table to record the error when the first duke@435: // attempt to resolve a reference to a class has failed. duke@435: void SystemDictionary::add_resolution_error(constantPoolHandle pool, int which, symbolHandle error) { duke@435: unsigned int hash = resolution_errors()->compute_hash(pool, which); duke@435: int index = resolution_errors()->hash_to_index(hash); duke@435: { duke@435: MutexLocker ml(SystemDictionary_lock, Thread::current()); duke@435: resolution_errors()->add_entry(index, hash, pool, which, error); duke@435: } duke@435: } duke@435: duke@435: // Lookup resolution error table. Returns error if found, otherwise NULL. duke@435: symbolOop SystemDictionary::find_resolution_error(constantPoolHandle pool, int which) { duke@435: unsigned int hash = resolution_errors()->compute_hash(pool, which); duke@435: int index = resolution_errors()->hash_to_index(hash); duke@435: { duke@435: MutexLocker ml(SystemDictionary_lock, Thread::current()); duke@435: ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which); duke@435: return (entry != NULL) ? entry->error() : (symbolOop)NULL; duke@435: } duke@435: } duke@435: duke@435: duke@435: // Make sure all class components (including arrays) in the given duke@435: // signature will be resolved to the same class in both loaders. duke@435: // Returns the name of the type that failed a loader constraint check, or duke@435: // NULL if no constraint failed. The returned C string needs cleaning up duke@435: // with a ResourceMark in the caller duke@435: char* SystemDictionary::check_signature_loaders(symbolHandle signature, duke@435: Handle loader1, Handle loader2, duke@435: bool is_method, TRAPS) { duke@435: // Nothing to do if loaders are the same. duke@435: if (loader1() == loader2()) { duke@435: return NULL; duke@435: } duke@435: duke@435: SignatureStream sig_strm(signature, is_method); duke@435: while (!sig_strm.is_done()) { duke@435: if (sig_strm.is_object()) { duke@435: symbolOop s = sig_strm.as_symbol(CHECK_NULL); duke@435: symbolHandle sig (THREAD, s); duke@435: if (!add_loader_constraint(sig, loader1, loader2, THREAD)) { duke@435: return sig()->as_C_string(); duke@435: } duke@435: } duke@435: sig_strm.next(); duke@435: } duke@435: return NULL; duke@435: } duke@435: duke@435: duke@435: // Since the identity hash code for symbols changes when the symbols are duke@435: // moved from the regular perm gen (hash in the mark word) to the shared duke@435: // spaces (hash is the address), the classes loaded into the dictionary duke@435: // may be in the wrong buckets. duke@435: duke@435: void SystemDictionary::reorder_dictionary() { duke@435: dictionary()->reorder_dictionary(); duke@435: } duke@435: duke@435: duke@435: void SystemDictionary::copy_buckets(char** top, char* end) { duke@435: dictionary()->copy_buckets(top, end); duke@435: } duke@435: duke@435: duke@435: void SystemDictionary::copy_table(char** top, char* end) { duke@435: dictionary()->copy_table(top, end); duke@435: } duke@435: duke@435: duke@435: void SystemDictionary::reverse() { duke@435: dictionary()->reverse(); duke@435: } duke@435: duke@435: int SystemDictionary::number_of_classes() { duke@435: return dictionary()->number_of_entries(); duke@435: } duke@435: duke@435: duke@435: // ---------------------------------------------------------------------------- duke@435: #ifndef PRODUCT duke@435: duke@435: void SystemDictionary::print() { duke@435: dictionary()->print(); duke@435: duke@435: // Placeholders duke@435: GCMutexLocker mu(SystemDictionary_lock); duke@435: placeholders()->print(); duke@435: duke@435: // loader constraints - print under SD_lock duke@435: constraints()->print(); duke@435: } duke@435: duke@435: #endif duke@435: duke@435: void SystemDictionary::verify() { duke@435: guarantee(dictionary() != NULL, "Verify of system dictionary failed"); duke@435: guarantee(constraints() != NULL, duke@435: "Verify of loader constraints failed"); duke@435: guarantee(dictionary()->number_of_entries() >= 0 && duke@435: placeholders()->number_of_entries() >= 0, duke@435: "Verify of system dictionary failed"); duke@435: duke@435: // Verify dictionary duke@435: dictionary()->verify(); duke@435: duke@435: GCMutexLocker mu(SystemDictionary_lock); duke@435: placeholders()->verify(); duke@435: duke@435: // Verify constraint table duke@435: guarantee(constraints() != NULL, "Verify of loader constraints failed"); duke@435: constraints()->verify(dictionary()); duke@435: } duke@435: duke@435: duke@435: void SystemDictionary::verify_obj_klass_present(Handle obj, duke@435: symbolHandle class_name, duke@435: Handle class_loader) { duke@435: GCMutexLocker mu(SystemDictionary_lock); duke@435: oop probe = find_class_or_placeholder(class_name, class_loader); duke@435: if (probe == NULL) { duke@435: probe = SystemDictionary::find_shared_class(class_name); duke@435: } duke@435: guarantee(probe != NULL && duke@435: (!probe->is_klass() || probe == obj()), duke@435: "Loaded klasses should be in SystemDictionary"); duke@435: } duke@435: duke@435: #ifndef PRODUCT duke@435: duke@435: // statistics code duke@435: class ClassStatistics: AllStatic { duke@435: private: duke@435: static int nclasses; // number of classes duke@435: static int nmethods; // number of methods duke@435: static int nmethoddata; // number of methodData duke@435: static int class_size; // size of class objects in words duke@435: static int method_size; // size of method objects in words duke@435: static int debug_size; // size of debug info in methods duke@435: static int methoddata_size; // size of methodData objects in words duke@435: duke@435: static void do_class(klassOop k) { duke@435: nclasses++; duke@435: class_size += k->size(); duke@435: if (k->klass_part()->oop_is_instance()) { duke@435: instanceKlass* ik = (instanceKlass*)k->klass_part(); duke@435: class_size += ik->methods()->size(); duke@435: class_size += ik->constants()->size(); duke@435: class_size += ik->local_interfaces()->size(); duke@435: class_size += ik->transitive_interfaces()->size(); duke@435: // We do not have to count implementors, since we only store one! duke@435: class_size += ik->fields()->size(); duke@435: } duke@435: } duke@435: duke@435: static void do_method(methodOop m) { duke@435: nmethods++; duke@435: method_size += m->size(); duke@435: // class loader uses same objArray for empty vectors, so don't count these duke@435: if (m->exception_table()->length() != 0) method_size += m->exception_table()->size(); duke@435: if (m->has_stackmap_table()) { duke@435: method_size += m->stackmap_data()->size(); duke@435: } duke@435: duke@435: methodDataOop mdo = m->method_data(); duke@435: if (mdo != NULL) { duke@435: nmethoddata++; duke@435: methoddata_size += mdo->size(); duke@435: } duke@435: } duke@435: duke@435: public: duke@435: static void print() { duke@435: SystemDictionary::classes_do(do_class); duke@435: SystemDictionary::methods_do(do_method); duke@435: tty->print_cr("Class statistics:"); duke@435: tty->print_cr("%d classes (%d bytes)", nclasses, class_size * oopSize); duke@435: tty->print_cr("%d methods (%d bytes = %d base + %d debug info)", nmethods, duke@435: (method_size + debug_size) * oopSize, method_size * oopSize, debug_size * oopSize); duke@435: tty->print_cr("%d methoddata (%d bytes)", nmethoddata, methoddata_size * oopSize); duke@435: } duke@435: }; duke@435: duke@435: duke@435: int ClassStatistics::nclasses = 0; duke@435: int ClassStatistics::nmethods = 0; duke@435: int ClassStatistics::nmethoddata = 0; duke@435: int ClassStatistics::class_size = 0; duke@435: int ClassStatistics::method_size = 0; duke@435: int ClassStatistics::debug_size = 0; duke@435: int ClassStatistics::methoddata_size = 0; duke@435: duke@435: void SystemDictionary::print_class_statistics() { duke@435: ResourceMark rm; duke@435: ClassStatistics::print(); duke@435: } duke@435: duke@435: duke@435: class MethodStatistics: AllStatic { duke@435: public: duke@435: enum { duke@435: max_parameter_size = 10 duke@435: }; duke@435: private: duke@435: duke@435: static int _number_of_methods; duke@435: static int _number_of_final_methods; duke@435: static int _number_of_static_methods; duke@435: static int _number_of_native_methods; duke@435: static int _number_of_synchronized_methods; duke@435: static int _number_of_profiled_methods; duke@435: static int _number_of_bytecodes; duke@435: static int _parameter_size_profile[max_parameter_size]; duke@435: static int _bytecodes_profile[Bytecodes::number_of_java_codes]; duke@435: duke@435: static void initialize() { duke@435: _number_of_methods = 0; duke@435: _number_of_final_methods = 0; duke@435: _number_of_static_methods = 0; duke@435: _number_of_native_methods = 0; duke@435: _number_of_synchronized_methods = 0; duke@435: _number_of_profiled_methods = 0; duke@435: _number_of_bytecodes = 0; duke@435: for (int i = 0; i < max_parameter_size ; i++) _parameter_size_profile[i] = 0; duke@435: for (int j = 0; j < Bytecodes::number_of_java_codes; j++) _bytecodes_profile [j] = 0; duke@435: }; duke@435: duke@435: static void do_method(methodOop m) { duke@435: _number_of_methods++; duke@435: // collect flag info duke@435: if (m->is_final() ) _number_of_final_methods++; duke@435: if (m->is_static() ) _number_of_static_methods++; duke@435: if (m->is_native() ) _number_of_native_methods++; duke@435: if (m->is_synchronized()) _number_of_synchronized_methods++; duke@435: if (m->method_data() != NULL) _number_of_profiled_methods++; duke@435: // collect parameter size info (add one for receiver, if any) duke@435: _parameter_size_profile[MIN2(m->size_of_parameters() + (m->is_static() ? 0 : 1), max_parameter_size - 1)]++; duke@435: // collect bytecodes info duke@435: { duke@435: Thread *thread = Thread::current(); duke@435: HandleMark hm(thread); duke@435: BytecodeStream s(methodHandle(thread, m)); duke@435: Bytecodes::Code c; duke@435: while ((c = s.next()) >= 0) { duke@435: _number_of_bytecodes++; duke@435: _bytecodes_profile[c]++; duke@435: } duke@435: } duke@435: } duke@435: duke@435: public: duke@435: static void print() { duke@435: initialize(); duke@435: SystemDictionary::methods_do(do_method); duke@435: // generate output duke@435: tty->cr(); duke@435: tty->print_cr("Method statistics (static):"); duke@435: // flag distribution duke@435: tty->cr(); duke@435: tty->print_cr("%6d final methods %6.1f%%", _number_of_final_methods , _number_of_final_methods * 100.0F / _number_of_methods); duke@435: tty->print_cr("%6d static methods %6.1f%%", _number_of_static_methods , _number_of_static_methods * 100.0F / _number_of_methods); duke@435: tty->print_cr("%6d native methods %6.1f%%", _number_of_native_methods , _number_of_native_methods * 100.0F / _number_of_methods); duke@435: tty->print_cr("%6d synchronized methods %6.1f%%", _number_of_synchronized_methods, _number_of_synchronized_methods * 100.0F / _number_of_methods); duke@435: tty->print_cr("%6d profiled methods %6.1f%%", _number_of_profiled_methods, _number_of_profiled_methods * 100.0F / _number_of_methods); duke@435: // parameter size profile duke@435: tty->cr(); duke@435: { int tot = 0; duke@435: int avg = 0; duke@435: for (int i = 0; i < max_parameter_size; i++) { duke@435: int n = _parameter_size_profile[i]; duke@435: tot += n; duke@435: avg += n*i; duke@435: tty->print_cr("parameter size = %1d: %6d methods %5.1f%%", i, n, n * 100.0F / _number_of_methods); duke@435: } duke@435: assert(tot == _number_of_methods, "should be the same"); duke@435: tty->print_cr(" %6d methods 100.0%%", _number_of_methods); duke@435: tty->print_cr("(average parameter size = %3.1f including receiver, if any)", (float)avg / _number_of_methods); duke@435: } duke@435: // bytecodes profile duke@435: tty->cr(); duke@435: { int tot = 0; duke@435: for (int i = 0; i < Bytecodes::number_of_java_codes; i++) { duke@435: if (Bytecodes::is_defined(i)) { duke@435: Bytecodes::Code c = Bytecodes::cast(i); duke@435: int n = _bytecodes_profile[c]; duke@435: tot += n; duke@435: tty->print_cr("%9d %7.3f%% %s", n, n * 100.0F / _number_of_bytecodes, Bytecodes::name(c)); duke@435: } duke@435: } duke@435: assert(tot == _number_of_bytecodes, "should be the same"); duke@435: tty->print_cr("%9d 100.000%%", _number_of_bytecodes); duke@435: } duke@435: tty->cr(); duke@435: } duke@435: }; duke@435: duke@435: int MethodStatistics::_number_of_methods; duke@435: int MethodStatistics::_number_of_final_methods; duke@435: int MethodStatistics::_number_of_static_methods; duke@435: int MethodStatistics::_number_of_native_methods; duke@435: int MethodStatistics::_number_of_synchronized_methods; duke@435: int MethodStatistics::_number_of_profiled_methods; duke@435: int MethodStatistics::_number_of_bytecodes; duke@435: int MethodStatistics::_parameter_size_profile[MethodStatistics::max_parameter_size]; duke@435: int MethodStatistics::_bytecodes_profile[Bytecodes::number_of_java_codes]; duke@435: duke@435: duke@435: void SystemDictionary::print_method_statistics() { duke@435: MethodStatistics::print(); duke@435: } duke@435: duke@435: #endif // PRODUCT