/* * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. * */ #include "precompiled.hpp" #include "jvm.h" #include "aot/aotLoader.hpp" #include "classfile/classFileParser.hpp" #include "classfile/classFileStream.hpp" #include "classfile/classLoader.hpp" #include "classfile/classLoaderData.inline.hpp" #include "classfile/classLoaderExt.hpp" #include "classfile/dictionary.hpp" #include "classfile/javaClasses.inline.hpp" #include "classfile/klassFactory.hpp" #include "classfile/loaderConstraints.hpp" #include "classfile/packageEntry.hpp" #include "classfile/placeholders.hpp" #include "classfile/protectionDomainCache.hpp" #include "classfile/resolutionErrors.hpp" #include "classfile/stringTable.hpp" #include "classfile/systemDictionary.hpp" #include "classfile/vmSymbols.hpp" #include "code/codeCache.hpp" #include "compiler/compileBroker.hpp" #include "gc/shared/gcTraceTime.inline.hpp" #include "gc/shared/oopStorage.inline.hpp" #include "interpreter/bytecodeStream.hpp" #include "interpreter/interpreter.hpp" #include "logging/log.hpp" #include "logging/logStream.hpp" #include "memory/filemap.hpp" #include "memory/metaspaceClosure.hpp" #include "memory/oopFactory.hpp" #include "memory/resourceArea.hpp" #include "oops/access.inline.hpp" #include "oops/instanceKlass.hpp" #include "oops/instanceRefKlass.hpp" #include "oops/klass.inline.hpp" #include "oops/method.inline.hpp" #include "oops/methodData.hpp" #include "oops/objArrayKlass.hpp" #include "oops/objArrayOop.inline.hpp" #include "oops/oop.inline.hpp" #include "oops/symbol.hpp" #include "oops/typeArrayKlass.hpp" #include "prims/jvmtiEnvBase.hpp" #include "prims/resolvedMethodTable.hpp" #include "prims/methodHandles.hpp" #include "runtime/arguments.hpp" #include "runtime/arguments_ext.hpp" #include "runtime/biasedLocking.hpp" #include "runtime/fieldType.hpp" #include "runtime/handles.inline.hpp" #include "runtime/java.hpp" #include "runtime/javaCalls.hpp" #include "runtime/mutexLocker.hpp" #include "runtime/orderAccess.inline.hpp" #include "runtime/sharedRuntime.hpp" #include "runtime/signature.hpp" #include "services/classLoadingService.hpp" #include "services/diagnosticCommand.hpp" #include "services/threadService.hpp" #include "trace/tracing.hpp" #include "utilities/macros.hpp" #if INCLUDE_CDS #include "classfile/sharedClassUtil.hpp" #include "classfile/systemDictionaryShared.hpp" #endif #if INCLUDE_JVMCI #include "jvmci/jvmciRuntime.hpp" #endif PlaceholderTable* SystemDictionary::_placeholders = NULL; Dictionary* SystemDictionary::_shared_dictionary = NULL; LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL; ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL; SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL; ProtectionDomainCacheTable* SystemDictionary::_pd_cache_table = NULL; int SystemDictionary::_number_of_modifications = 0; oop SystemDictionary::_system_loader_lock_obj = NULL; InstanceKlass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT] = { NULL /*, NULL...*/ }; InstanceKlass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ }; oop SystemDictionary::_java_system_loader = NULL; oop SystemDictionary::_java_platform_loader = NULL; bool SystemDictionary::_has_checkPackageAccess = false; // lazily initialized klass variables InstanceKlass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL; // Default ProtectionDomainCacheSize value const int defaultProtectionDomainCacheSize = 1009; OopStorage* SystemDictionary::_vm_weak_oop_storage = NULL; // ---------------------------------------------------------------------------- // Java-level SystemLoader and PlatformLoader oop SystemDictionary::java_system_loader() { return _java_system_loader; } oop SystemDictionary::java_platform_loader() { return _java_platform_loader; } void SystemDictionary::compute_java_loaders(TRAPS) { JavaValue result(T_OBJECT); InstanceKlass* class_loader_klass = SystemDictionary::ClassLoader_klass(); JavaCalls::call_static(&result, class_loader_klass, vmSymbols::getSystemClassLoader_name(), vmSymbols::void_classloader_signature(), CHECK); _java_system_loader = (oop)result.get_jobject(); JavaCalls::call_static(&result, class_loader_klass, vmSymbols::getPlatformClassLoader_name(), vmSymbols::void_classloader_signature(), CHECK); _java_platform_loader = (oop)result.get_jobject(); CDS_ONLY(SystemDictionaryShared::initialize(CHECK);) } ClassLoaderData* SystemDictionary::register_loader(Handle class_loader) { if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data(); return ClassLoaderDataGraph::find_or_create(class_loader); } // ---------------------------------------------------------------------------- // Parallel class loading check bool SystemDictionary::is_parallelCapable(Handle class_loader) { if (class_loader.is_null()) return true; if (AlwaysLockClassLoader) return false; return java_lang_ClassLoader::parallelCapable(class_loader()); } // ---------------------------------------------------------------------------- // ParallelDefineClass flag does not apply to bootclass loader bool SystemDictionary::is_parallelDefine(Handle class_loader) { if (class_loader.is_null()) return false; if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) { return true; } return false; } // Returns true if the passed class loader is the builtin application class loader // or a custom system class loader. A customer system class loader can be // specified via -Djava.system.class.loader. bool SystemDictionary::is_system_class_loader(oop class_loader) { if (class_loader == NULL) { return false; } return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() || oopDesc::equals(class_loader, _java_system_loader)); } // Returns true if the passed class loader is the platform class loader. bool SystemDictionary::is_platform_class_loader(oop class_loader) { if (class_loader == NULL) { return false; } return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass()); } // ---------------------------------------------------------------------------- // Resolving of classes // Forwards to resolve_or_null Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) { Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD); if (HAS_PENDING_EXCEPTION || klass == NULL) { // can return a null klass klass = handle_resolution_exception(class_name, throw_error, klass, THREAD); } return klass; } Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name, bool throw_error, Klass* klass, TRAPS) { if (HAS_PENDING_EXCEPTION) { // If we have a pending exception we forward it to the caller, unless throw_error is true, // in which case we have to check whether the pending exception is a ClassNotFoundException, // and if so convert it to a NoClassDefFoundError // And chain the original ClassNotFoundException if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) { ResourceMark rm(THREAD); assert(klass == NULL, "Should not have result with exception pending"); Handle e(THREAD, PENDING_EXCEPTION); CLEAR_PENDING_EXCEPTION; THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e); } else { return NULL; } } // Class not found, throw appropriate error or exception depending on value of throw_error if (klass == NULL) { ResourceMark rm(THREAD); if (throw_error) { THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string()); } else { THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string()); } } return klass; } Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, bool throw_error, TRAPS) { return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD); } // Forwards to resolve_instance_class_or_null Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) { assert(THREAD->can_call_java(), "can not load classes with compiler thread: class=%s, classloader=%s", class_name->as_C_string(), class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string()); if (FieldType::is_array(class_name)) { return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD); } else if (FieldType::is_obj(class_name)) { ResourceMark rm(THREAD); // Ignore wrapping L and ;. TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1, class_name->utf8_length() - 2, CHECK_NULL); return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD); } else { return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD); } } Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) { return resolve_or_null(class_name, Handle(), Handle(), THREAD); } // Forwards to resolve_instance_class_or_null Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) { assert(FieldType::is_array(class_name), "must be array"); Klass* k = NULL; FieldArrayInfo fd; // dimension and object_key in FieldArrayInfo are assigned as a side-effect // of this call BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL); if (t == T_OBJECT) { // naked oop "k" is OK here -- we assign back into it k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(), class_loader, protection_domain, CHECK_NULL); if (k != NULL) { k = k->array_klass(fd.dimension(), CHECK_NULL); } } else { k = Universe::typeArrayKlassObj(t); k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL); } return k; } // Must be called for any super-class or super-interface resolution // during class definition to allow class circularity checking // super-interface callers: // parse_interfaces - for defineClass & jvmtiRedefineClasses // super-class callers: // ClassFileParser - for defineClass & jvmtiRedefineClasses // load_shared_class - while loading a class from shared archive // resolve_instance_class_or_null: // via: handle_parallel_super_load // when resolving a class that has an existing placeholder with // a saved superclass [i.e. a defineClass is currently in progress] // if another thread is trying to resolve the class, it must do // super-class checks on its own thread to catch class circularity // This last call is critical in class circularity checking for cases // where classloading is delegated to different threads and the // classloader lock is released. // Take the case: Base->Super->Base // 1. If thread T1 tries to do a defineClass of class Base // resolve_super_or_fail creates placeholder: T1, Base (super Super) // 2. resolve_instance_class_or_null does not find SD or placeholder for Super // so it tries to load Super // 3. If we load the class internally, or user classloader uses same thread // loadClassFromxxx or defineClass via parseClassFile Super ... // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base) // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base // 3.4 calls resolve_super_or_fail Base // 3.5 finds T1,Base -> throws class circularity //OR 4. If T2 tries to resolve Super via defineClass Super ... // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base) // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super) // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2 // 4.4 finds T2, Super -> throws class circularity // Must be called, even if superclass is null, since this is // where the placeholder entry is created which claims this // thread is loading this class/classloader. // Be careful when modifying this code: once you have run // placeholders()->find_and_add(PlaceholderTable::LOAD_SUPER), // you need to find_and_remove it before returning. // So be careful to not exit with a CHECK_ macro betweeen these calls. Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name, Symbol* class_name, Handle class_loader, Handle protection_domain, bool is_superclass, TRAPS) { #if INCLUDE_CDS if (DumpSharedSpaces) { // Special processing for CDS dump time. Klass* k = SystemDictionaryShared::dump_time_resolve_super_or_fail(child_name, class_name, class_loader, protection_domain, is_superclass, CHECK_NULL); if (k) { return k; } } #endif // INCLUDE_CDS // Double-check, if child class is already loaded, just return super-class,interface // Don't add a placedholder if already loaded, i.e. already in appropriate class loader // dictionary. // Make sure there's a placeholder for the *child* before resolving. // Used as a claim that this thread is currently loading superclass/classloader // Used here for ClassCircularity checks and also for heap verification // (every InstanceKlass needs to be in its class loader dictionary or have a placeholder). // Must check ClassCircularity before checking if super class is already loaded. // // We might not already have a placeholder if this child_name was // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass); // the name of the class might not be known until the stream is actually // parsed. // Bugs 4643874, 4715493 ClassLoaderData* loader_data = class_loader_data(class_loader); Dictionary* dictionary = loader_data->dictionary(); unsigned int d_hash = dictionary->compute_hash(child_name); unsigned int p_hash = placeholders()->compute_hash(child_name); int p_index = placeholders()->hash_to_index(p_hash); // can't throw error holding a lock bool child_already_loaded = false; bool throw_circularity_error = false; { MutexLocker mu(SystemDictionary_lock, THREAD); Klass* childk = find_class(d_hash, child_name, dictionary); Klass* quicksuperk; // to support // loading: if child done loading, just return superclass // if class_name, & class_loader don't match: // if initial define, SD update will give LinkageError // if redefine: compare_class_versions will give HIERARCHY_CHANGED // so we don't throw an exception here. // see: nsk redefclass014 & java.lang.instrument Instrument032 if ((childk != NULL ) && (is_superclass) && ((quicksuperk = childk->super()) != NULL) && ((quicksuperk->name() == class_name) && (oopDesc::equals(quicksuperk->class_loader(), class_loader())))) { return quicksuperk; } else { PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data); if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) { throw_circularity_error = true; } } if (!throw_circularity_error) { // Be careful not to exit resolve_super PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD); } } if (throw_circularity_error) { ResourceMark rm(THREAD); THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string()); } // java.lang.Object should have been found above assert(class_name != NULL, "null super class for resolving"); // Resolve the super class or interface, check results on return Klass* superk = SystemDictionary::resolve_or_null(class_name, class_loader, protection_domain, THREAD); // Clean up of placeholders moved so that each classloadAction registrar self-cleans up // It is no longer necessary to keep the placeholder table alive until update_dictionary // or error. GC used to walk the placeholder table as strong roots. // The instanceKlass is kept alive because the class loader is on the stack, // which keeps the loader_data alive, as well as all instanceKlasses in // the loader_data. parseClassFile adds the instanceKlass to loader_data. { MutexLocker mu(SystemDictionary_lock, THREAD); placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD); SystemDictionary_lock->notify_all(); } if (HAS_PENDING_EXCEPTION || superk == NULL) { // can null superk superk = handle_resolution_exception(class_name, true, superk, THREAD); } return superk; } void SystemDictionary::validate_protection_domain(InstanceKlass* klass, Handle class_loader, Handle protection_domain, TRAPS) { if(!has_checkPackageAccess()) return; // Now we have to call back to java to check if the initating class has access JavaValue result(T_VOID); LogTarget(Debug, protectiondomain) lt; if (lt.is_enabled()) { ResourceMark rm; // Print out trace information LogStream ls(lt); ls.print_cr("Checking package access"); ls.print("class loader: "); class_loader()->print_value_on(&ls); ls.print(" protection domain: "); protection_domain()->print_value_on(&ls); ls.print(" loading: "); klass->print_value_on(&ls); ls.cr(); } // This handle and the class_loader handle passed in keeps this class from // being unloaded through several GC points. // The class_loader handle passed in is the initiating loader. Handle mirror(THREAD, klass->java_mirror()); InstanceKlass* system_loader = SystemDictionary::ClassLoader_klass(); JavaCalls::call_special(&result, class_loader, system_loader, vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature(), mirror, protection_domain, THREAD); if (HAS_PENDING_EXCEPTION) { log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!"); } else { log_debug(protectiondomain)("granted"); } if (HAS_PENDING_EXCEPTION) return; // If no exception has been thrown, we have validated the protection domain // Insert the protection domain of the initiating class into the set. { ClassLoaderData* loader_data = class_loader_data(class_loader); Dictionary* dictionary = loader_data->dictionary(); Symbol* kn = klass->name(); unsigned int d_hash = dictionary->compute_hash(kn); MutexLocker mu(SystemDictionary_lock, THREAD); int d_index = dictionary->hash_to_index(d_hash); dictionary->add_protection_domain(d_index, d_hash, klass, protection_domain, THREAD); } } // We only get here if this thread finds that another thread // has already claimed the placeholder token for the current operation, // but that other thread either never owned or gave up the // object lock // Waits on SystemDictionary_lock to indicate placeholder table updated // On return, caller must recheck placeholder table state // // We only get here if // 1) custom classLoader, i.e. not bootstrap classloader // 2) custom classLoader has broken the class loader objectLock // so another thread got here in parallel // // lockObject must be held. // Complicated dance due to lock ordering: // Must first release the classloader object lock to // allow initial definer to complete the class definition // and to avoid deadlock // Reclaim classloader lock object with same original recursion count // Must release SystemDictionary_lock after notify, since // class loader lock must be claimed before SystemDictionary_lock // to prevent deadlocks // // The notify allows applications that did an untimed wait() on // the classloader object lock to not hang. void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) { assert_lock_strong(SystemDictionary_lock); bool calledholdinglock = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject); assert(calledholdinglock,"must hold lock for notify"); assert((!oopDesc::equals(lockObject(), _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait"); ObjectSynchronizer::notifyall(lockObject, THREAD); intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD); SystemDictionary_lock->wait(); SystemDictionary_lock->unlock(); ObjectSynchronizer::reenter(lockObject, recursions, THREAD); SystemDictionary_lock->lock(); } // If the class in is in the placeholder table, class loading is in progress // For cases where the application changes threads to load classes, it // is critical to ClassCircularity detection that we try loading // the superclass on the same thread internally, so we do parallel // super class loading here. // This also is critical in cases where the original thread gets stalled // even in non-circularity situations. // Note: must call resolve_super_or_fail even if null super - // to force placeholder entry creation for this class for circularity detection // Caller must check for pending exception // Returns non-null Klass* if other thread has completed load // and we are done, // If return null Klass* and no pending exception, the caller must load the class InstanceKlass* SystemDictionary::handle_parallel_super_load( Symbol* name, Symbol* superclassname, Handle class_loader, Handle protection_domain, Handle lockObject, TRAPS) { ClassLoaderData* loader_data = class_loader_data(class_loader); Dictionary* dictionary = loader_data->dictionary(); unsigned int d_hash = dictionary->compute_hash(name); unsigned int p_hash = placeholders()->compute_hash(name); int p_index = placeholders()->hash_to_index(p_hash); // superk is not used, resolve_super called for circularity check only // This code is reached in two situations. One if this thread // is loading the same class twice (e.g. ClassCircularity, or // java.lang.instrument). // The second is if another thread started the resolve_super first // and has not yet finished. // In both cases the original caller will clean up the placeholder // entry on error. Klass* superk = SystemDictionary::resolve_super_or_fail(name, superclassname, class_loader, protection_domain, true, CHECK_NULL); // parallelCapable class loaders do NOT wait for parallel superclass loads to complete // Serial class loaders and bootstrap classloader do wait for superclass loads if (!class_loader.is_null() && is_parallelCapable(class_loader)) { MutexLocker mu(SystemDictionary_lock, THREAD); // Check if classloading completed while we were loading superclass or waiting return find_class(d_hash, name, dictionary); } // must loop to both handle other placeholder updates // and spurious notifications bool super_load_in_progress = true; PlaceholderEntry* placeholder; while (super_load_in_progress) { MutexLocker mu(SystemDictionary_lock, THREAD); // Check if classloading completed while we were loading superclass or waiting InstanceKlass* check = find_class(d_hash, name, dictionary); if (check != NULL) { // Klass is already loaded, so just return it return check; } else { placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data); if (placeholder && placeholder->super_load_in_progress() ){ // We only get here if the application has released the // classloader lock when another thread was in the middle of loading a // superclass/superinterface for this class, and now // this thread is also trying to load this class. // To minimize surprises, the first thread that started to // load a class should be the one to complete the loading // with the classfile it initially expected. // This logic has the current thread wait once it has done // all the superclass/superinterface loading it can, until // the original thread completes the class loading or fails // If it completes we will use the resulting InstanceKlass // which we will find below in the systemDictionary. // We also get here for parallel bootstrap classloader if (class_loader.is_null()) { SystemDictionary_lock->wait(); } else { double_lock_wait(lockObject, THREAD); } } else { // If not in SD and not in PH, other thread's load must have failed super_load_in_progress = false; } } } return NULL; } static void post_class_load_event(EventClassLoad* event, const InstanceKlass* k, const ClassLoaderData* init_cld) { #if INCLUDE_TRACE assert(event != NULL, "invariant"); assert(k != NULL, "invariant"); if (event->should_commit()) { event->set_loadedClass(k); event->set_definingClassLoader(k->class_loader_data()); event->set_initiatingClassLoader(init_cld); event->commit(); } #endif // INCLUDE_TRACE } static void class_define_event(InstanceKlass* k, const ClassLoaderData* def_cld) { #if INCLUDE_TRACE EventClassDefine event; if (event.should_commit()) { event.set_definedClass(k); event.set_definingClassLoader(def_cld); event.commit(); } #endif // INCLUDE_TRACE } // Be careful when modifying this code: once you have run // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE), // you need to find_and_remove it before returning. // So be careful to not exit with a CHECK_ macro betweeen these calls. Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name, Handle class_loader, Handle protection_domain, TRAPS) { assert(name != NULL && !FieldType::is_array(name) && !FieldType::is_obj(name), "invalid class name"); EventClassLoad class_load_start_event; HandleMark hm(THREAD); // Fix for 4474172; see evaluation for more details class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader())); ClassLoaderData* loader_data = register_loader(class_loader); Dictionary* dictionary = loader_data->dictionary(); unsigned int d_hash = dictionary->compute_hash(name); // Do lookup to see if class already exist and the protection domain // has the right access // This call uses find which checks protection domain already matches // All subsequent calls use find_class, and set has_loaded_class so that // before we return a result we call out to java to check for valid protection domain // to allow returning the Klass* and add it to the pd_set if it is valid { Klass* probe = dictionary->find(d_hash, name, protection_domain); if (probe != NULL) return probe; } // Non-bootstrap class loaders will call out to class loader and // define via jvm/jni_DefineClass which will acquire the // class loader object lock to protect against multiple threads // defining the class in parallel by accident. // This lock must be acquired here so the waiter will find // any successful result in the SystemDictionary and not attempt // the define. // ParallelCapable Classloaders and the bootstrap classloader // do not acquire lock here. bool DoObjectLock = true; if (is_parallelCapable(class_loader)) { DoObjectLock = false; } unsigned int p_hash = placeholders()->compute_hash(name); int p_index = placeholders()->hash_to_index(p_hash); // Class is not in SystemDictionary so we have to do loading. // Make sure we are synchronized on the class loader before we proceed Handle lockObject = compute_loader_lock_object(class_loader, THREAD); check_loader_lock_contention(lockObject, THREAD); ObjectLocker ol(lockObject, THREAD, DoObjectLock); // Check again (after locking) if class already exist in SystemDictionary bool class_has_been_loaded = false; bool super_load_in_progress = false; bool havesupername = false; InstanceKlass* k = NULL; PlaceholderEntry* placeholder; Symbol* superclassname = NULL; { MutexLocker mu(SystemDictionary_lock, THREAD); InstanceKlass* check = find_class(d_hash, name, dictionary); if (check != NULL) { // Klass is already loaded, so just return it class_has_been_loaded = true; k = check; } else { placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data); if (placeholder && placeholder->super_load_in_progress()) { super_load_in_progress = true; if (placeholder->havesupername() == true) { superclassname = placeholder->supername(); havesupername = true; } } } } // If the class is in the placeholder table, class loading is in progress if (super_load_in_progress && havesupername==true) { k = handle_parallel_super_load(name, superclassname, class_loader, protection_domain, lockObject, THREAD); if (HAS_PENDING_EXCEPTION) { return NULL; } if (k != NULL) { class_has_been_loaded = true; } } bool throw_circularity_error = false; if (!class_has_been_loaded) { bool load_instance_added = false; // add placeholder entry to record loading instance class // Five cases: // All cases need to prevent modifying bootclasssearchpath // in parallel with a classload of same classname // Redefineclasses uses existence of the placeholder for the duration // of the class load to prevent concurrent redefinition of not completely // defined classes. // case 1. traditional classloaders that rely on the classloader object lock // - no other need for LOAD_INSTANCE // case 2. traditional classloaders that break the classloader object lock // as a deadlock workaround. Detection of this case requires that // this check is done while holding the classloader object lock, // and that lock is still held when calling classloader's loadClass. // For these classloaders, we ensure that the first requestor // completes the load and other requestors wait for completion. // case 3. Bootstrap classloader - don't own objectLocker // This classloader supports parallelism at the classloader level, // but only allows a single load of a class/classloader pair. // No performance benefit and no deadlock issues. // case 4. parallelCapable user level classloaders - without objectLocker // Allow parallel classloading of a class/classloader pair { MutexLocker mu(SystemDictionary_lock, THREAD); if (class_loader.is_null() || !is_parallelCapable(class_loader)) { PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data); if (oldprobe) { // only need check_seen_thread once, not on each loop // 6341374 java/lang/Instrument with -Xcomp if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) { throw_circularity_error = true; } else { // case 1: traditional: should never see load_in_progress. while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) { // case 3: bootstrap classloader: prevent futile classloading, // wait on first requestor if (class_loader.is_null()) { SystemDictionary_lock->wait(); } else { // case 2: traditional with broken classloader lock. wait on first // requestor. double_lock_wait(lockObject, THREAD); } // Check if classloading completed while we were waiting InstanceKlass* check = find_class(d_hash, name, dictionary); if (check != NULL) { // Klass is already loaded, so just return it k = check; class_has_been_loaded = true; } // check if other thread failed to load and cleaned up oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data); } } } } // All cases: add LOAD_INSTANCE holding SystemDictionary_lock // case 4: parallelCapable: allow competing threads to try // LOAD_INSTANCE in parallel if (!throw_circularity_error && !class_has_been_loaded) { PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD); load_instance_added = true; // For class loaders that do not acquire the classloader object lock, // if they did not catch another thread holding LOAD_INSTANCE, // need a check analogous to the acquire ObjectLocker/find_class // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL // one final check if the load has already completed // class loaders holding the ObjectLock shouldn't find the class here InstanceKlass* check = find_class(d_hash, name, dictionary); if (check != NULL) { // Klass is already loaded, so return it after checking/adding protection domain k = check; class_has_been_loaded = true; } } } // must throw error outside of owning lock if (throw_circularity_error) { assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup"); ResourceMark rm(THREAD); THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string()); } if (!class_has_been_loaded) { // Do actual loading k = load_instance_class(name, class_loader, THREAD); // If everything was OK (no exceptions, no null return value), and // class_loader is NOT the defining loader, do a little more bookkeeping. if (!HAS_PENDING_EXCEPTION && k != NULL && !oopDesc::equals(k->class_loader(), class_loader())) { check_constraints(d_hash, k, class_loader, false, THREAD); // Need to check for a PENDING_EXCEPTION again; check_constraints // can throw and doesn't use the CHECK macro. if (!HAS_PENDING_EXCEPTION) { { // Grabbing the Compile_lock prevents systemDictionary updates // during compilations. MutexLocker mu(Compile_lock, THREAD); update_dictionary(d_hash, p_index, p_hash, k, class_loader, THREAD); } if (JvmtiExport::should_post_class_load()) { Thread *thread = THREAD; assert(thread->is_Java_thread(), "thread->is_Java_thread()"); JvmtiExport::post_class_load((JavaThread *) thread, k); } } } } // load_instance_class if (load_instance_added == true) { // clean up placeholder entries for LOAD_INSTANCE success or error // This brackets the SystemDictionary updates for both defining // and initiating loaders MutexLocker mu(SystemDictionary_lock, THREAD); placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD); SystemDictionary_lock->notify_all(); } } if (HAS_PENDING_EXCEPTION || k == NULL) { return NULL; } post_class_load_event(&class_load_start_event, k, loader_data); #ifdef ASSERT { ClassLoaderData* loader_data = k->class_loader_data(); MutexLocker mu(SystemDictionary_lock, THREAD); Klass* kk = find_class(name, loader_data); assert(kk == k, "should be present in dictionary"); } #endif // return if the protection domain in NULL if (protection_domain() == NULL) return k; // Check the protection domain has the right access if (dictionary->is_valid_protection_domain(d_hash, name, protection_domain)) { return k; } // Verify protection domain. If it fails an exception is thrown validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL); return k; } // This routine does not lock the system dictionary. // // Since readers don't hold a lock, we must make sure that system // dictionary entries are only removed at a safepoint (when only one // thread is running), and are added to in a safe way (all links must // be updated in an MT-safe manner). // // Callers should be aware that an entry could be added just after // _dictionary->bucket(index) is read here, so the caller will not see // the new entry. Klass* SystemDictionary::find(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) { // The result of this call should be consistent with the result // of the call to resolve_instance_class_or_null(). // See evaluation 6790209 and 4474172 for more details. class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader())); ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader()); if (loader_data == NULL) { // If the ClassLoaderData has not been setup, // then the class loader has no entries in the dictionary. return NULL; } Dictionary* dictionary = loader_data->dictionary(); unsigned int d_hash = dictionary->compute_hash(class_name); return dictionary->find(d_hash, class_name, protection_domain); } // Look for a loaded instance or array klass by name. Do not do any loading. // return NULL in case of error. Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) { Klass* k = NULL; assert(class_name != NULL, "class name must be non NULL"); if (FieldType::is_array(class_name)) { // The name refers to an array. Parse the name. // dimension and object_key in FieldArrayInfo are assigned as a // side-effect of this call FieldArrayInfo fd; BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL)); if (t != T_OBJECT) { k = Universe::typeArrayKlassObj(t); } else { k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD); } if (k != NULL) { k = k->array_klass_or_null(fd.dimension()); } } else { k = find(class_name, class_loader, protection_domain, THREAD); } return k; } // Note: this method is much like resolve_from_stream, but // does not publish the classes via the SystemDictionary. // Handles unsafe_DefineAnonymousClass and redefineclasses // RedefinedClasses do not add to the class hierarchy InstanceKlass* SystemDictionary::parse_stream(Symbol* class_name, Handle class_loader, Handle protection_domain, ClassFileStream* st, const InstanceKlass* host_klass, GrowableArray* cp_patches, TRAPS) { EventClassLoad class_load_start_event; ClassLoaderData* loader_data; if (host_klass != NULL) { // Create a new CLD for anonymous class, that uses the same class loader // as the host_klass guarantee(oopDesc::equals(host_klass->class_loader(), class_loader()), "should be the same"); loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader); } else { loader_data = ClassLoaderData::class_loader_data(class_loader()); } assert(st != NULL, "invariant"); assert(st->need_verify(), "invariant"); // Parse stream and create a klass. // Note that we do this even though this klass might // already be present in the SystemDictionary, otherwise we would not // throw potential ClassFormatErrors. InstanceKlass* k = KlassFactory::create_from_stream(st, class_name, loader_data, protection_domain, host_klass, cp_patches, CHECK_NULL); if (host_klass != NULL && k != NULL) { // Anonymous classes must update ClassLoaderData holder (was host_klass loader) // so that they can be unloaded when the mirror is no longer referenced. k->class_loader_data()->initialize_holder(Handle(THREAD, k->java_mirror())); { MutexLocker mu_r(Compile_lock, THREAD); // Add to class hierarchy, initialize vtables, and do possible // deoptimizations. add_to_hierarchy(k, CHECK_NULL); // No exception, but can block // But, do not add to dictionary. // compiled code dependencies need to be validated anyway notice_modification(); } // Rewrite and patch constant pool here. k->link_class(CHECK_NULL); if (cp_patches != NULL) { k->constants()->patch_resolved_references(cp_patches); } // If it's anonymous, initialize it now, since nobody else will. k->eager_initialize(CHECK_NULL); // notify jvmti if (JvmtiExport::should_post_class_load()) { assert(THREAD->is_Java_thread(), "thread->is_Java_thread()"); JvmtiExport::post_class_load((JavaThread *) THREAD, k); } post_class_load_event(&class_load_start_event, k, loader_data); } assert(host_klass != NULL || NULL == cp_patches, "cp_patches only found with host_klass"); return k; } // Add a klass to the system from a stream (called by jni_DefineClass and // JVM_DefineClass). // Note: class_name can be NULL. In that case we do not know the name of // the class until we have parsed the stream. InstanceKlass* SystemDictionary::resolve_from_stream(Symbol* class_name, Handle class_loader, Handle protection_domain, ClassFileStream* st, TRAPS) { HandleMark hm(THREAD); // Classloaders that support parallelism, e.g. bootstrap classloader, // do not acquire lock here bool DoObjectLock = true; if (is_parallelCapable(class_loader)) { DoObjectLock = false; } ClassLoaderData* loader_data = register_loader(class_loader); // Make sure we are synchronized on the class loader before we proceed Handle lockObject = compute_loader_lock_object(class_loader, THREAD); check_loader_lock_contention(lockObject, THREAD); ObjectLocker ol(lockObject, THREAD, DoObjectLock); assert(st != NULL, "invariant"); // Parse the stream and create a klass. // Note that we do this even though this klass might // already be present in the SystemDictionary, otherwise we would not // throw potential ClassFormatErrors. InstanceKlass* k = NULL; #if INCLUDE_CDS if (!DumpSharedSpaces) { k = SystemDictionaryShared::lookup_from_stream(class_name, class_loader, protection_domain, st, CHECK_NULL); } #endif if (k == NULL) { if (st->buffer() == NULL) { return NULL; } k = KlassFactory::create_from_stream(st, class_name, loader_data, protection_domain, NULL, // host_klass NULL, // cp_patches CHECK_NULL); } assert(k != NULL, "no klass created"); Symbol* h_name = k->name(); assert(class_name == NULL || class_name == h_name, "name mismatch"); // Add class just loaded // If a class loader supports parallel classloading handle parallel define requests // find_or_define_instance_class may return a different InstanceKlass if (is_parallelCapable(class_loader)) { InstanceKlass* defined_k = find_or_define_instance_class(h_name, class_loader, k, THREAD); if (!HAS_PENDING_EXCEPTION && defined_k != k) { // If a parallel capable class loader already defined this class, register 'k' for cleanup. assert(defined_k != NULL, "Should have a klass if there's no exception"); loader_data->add_to_deallocate_list(k); k = defined_k; } } else { define_instance_class(k, THREAD); } // If defining the class throws an exception register 'k' for cleanup. if (HAS_PENDING_EXCEPTION) { assert(k != NULL, "Must have an instance klass here!"); loader_data->add_to_deallocate_list(k); return NULL; } // Make sure we have an entry in the SystemDictionary on success debug_only( { MutexLocker mu(SystemDictionary_lock, THREAD); Klass* check = find_class(h_name, k->class_loader_data()); assert(check == k, "should be present in the dictionary"); } ); return k; } #if INCLUDE_CDS void SystemDictionary::set_shared_dictionary(HashtableBucket* t, int length, int number_of_entries) { assert(length == _shared_dictionary_size * sizeof(HashtableBucket), "bad shared dictionary size."); _shared_dictionary = new Dictionary(ClassLoaderData::the_null_class_loader_data(), _shared_dictionary_size, t, number_of_entries); } // If there is a shared dictionary, then find the entry for the // given shared system class, if any. InstanceKlass* SystemDictionary::find_shared_class(Symbol* class_name) { if (shared_dictionary() != NULL) { unsigned int d_hash = shared_dictionary()->compute_hash(class_name); int d_index = shared_dictionary()->hash_to_index(d_hash); return shared_dictionary()->find_shared_class(d_index, d_hash, class_name); } else { return NULL; } } // Load a class from the shared spaces (found through the shared system // dictionary). Force the superclass and all interfaces to be loaded. // Update the class definition to include sibling classes and no // subclasses (yet). [Classes in the shared space are not part of the // object hierarchy until loaded.] InstanceKlass* SystemDictionary::load_shared_class( Symbol* class_name, Handle class_loader, TRAPS) { InstanceKlass* ik = find_shared_class(class_name); // Make sure we only return the boot class for the NULL classloader. if (ik != NULL && ik->is_shared_boot_class() && class_loader.is_null()) { Handle protection_domain; return load_shared_class(ik, class_loader, protection_domain, THREAD); } return NULL; } // Check if a shared class can be loaded by the specific classloader: // // NULL classloader: // - Module class from "modules" jimage. ModuleEntry must be defined in the classloader. // - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must // be defined in an unnamed module. bool SystemDictionary::is_shared_class_visible(Symbol* class_name, InstanceKlass* ik, Handle class_loader, TRAPS) { assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(), "Cannot use sharing if java.base is patched"); ResourceMark rm; int path_index = ik->shared_classpath_index(); ClassLoaderData* loader_data = class_loader_data(class_loader); if (path_index < 0) { // path_index < 0 indicates that the class is intended for a custom loader // and should not be loaded by boot/platform/app loaders if (loader_data->is_builtin_class_loader_data()) { return false; } else { return true; } } SharedClassPathEntry* ent = (SharedClassPathEntry*)FileMapInfo::shared_path(path_index); if (!Universe::is_module_initialized()) { assert(ent != NULL && ent->is_modules_image(), "Loading non-bootstrap classes before the module system is initialized"); assert(class_loader.is_null(), "sanity"); return true; } // Get the pkg_entry from the classloader TempNewSymbol pkg_name = NULL; PackageEntry* pkg_entry = NULL; ModuleEntry* mod_entry = NULL; const char* pkg_string = NULL; pkg_name = InstanceKlass::package_from_name(class_name, CHECK_false); if (pkg_name != NULL) { pkg_string = pkg_name->as_C_string(); if (loader_data != NULL) { pkg_entry = loader_data->packages()->lookup_only(pkg_name); } if (pkg_entry != NULL) { mod_entry = pkg_entry->module(); } } // If the archived class is from a module that has been patched at runtime, // the class cannot be loaded from the archive. if (mod_entry != NULL && mod_entry->is_patched()) { return false; } if (class_loader.is_null()) { assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry"); // The NULL classloader can load archived class originated from the // "modules" jimage and the -Xbootclasspath/a. For class from the // "modules" jimage, the PackageEntry/ModuleEntry must be defined // by the NULL classloader. if (mod_entry != NULL) { // PackageEntry/ModuleEntry is found in the classloader. Check if the // ModuleEntry's location agrees with the archived class' origination. if (ent->is_modules_image() && mod_entry->location()->starts_with("jrt:")) { return true; // Module class from the "module" jimage } } // If the archived class is not from the "module" jimage, the class can be // loaded by the NULL classloader if // // 1. the class is from the unamed package // 2. or, the class is not from a module defined in the NULL classloader // 3. or, the class is from an unamed module if (!ent->is_modules_image() && ik->is_shared_boot_class()) { // the class is from the -Xbootclasspath/a if (pkg_string == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) { assert(mod_entry == NULL || mod_entry == loader_data->unnamed_module(), "the unnamed module is not defined in the classloader"); return true; } } return false; } else { bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader( ik, class_loader, pkg_string, pkg_name, pkg_entry, mod_entry, CHECK_(false)); return res; } } InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik, Handle class_loader, Handle protection_domain, TRAPS) { if (ik != NULL) { Symbol* class_name = ik->name(); bool visible = is_shared_class_visible( class_name, ik, class_loader, CHECK_NULL); if (!visible) { return NULL; } // Resolve the superclass and interfaces. They must be the same // as in dump time, because the layout of depends on // the specific layout of ik->super() and ik->local_interfaces(). // // If unexpected superclass or interfaces are found, we cannot // load from the shared archive. if (ik->super() != NULL) { Symbol* cn = ik->super()->name(); Klass *s = resolve_super_or_fail(class_name, cn, class_loader, protection_domain, true, CHECK_NULL); if (s != ik->super()) { // The dynamically resolved super class is not the same as the one we used during dump time, // so we cannot use ik. return NULL; } else { assert(s->is_shared(), "must be"); } } Array* interfaces = ik->local_interfaces(); int num_interfaces = interfaces->length(); for (int index = 0; index < num_interfaces; index++) { Klass* k = interfaces->at(index); Symbol* name = k->name(); Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_NULL); if (k != i) { // The dynamically resolved interface class is not the same as the one we used during dump time, // so we cannot use ik. return NULL; } else { assert(i->is_shared(), "must be"); } } InstanceKlass* new_ik = KlassFactory::check_shared_class_file_load_hook( ik, class_name, class_loader, protection_domain, CHECK_NULL); if (new_ik != NULL) { // The class is changed by CFLH. Return the new class. The shared class is // not used. return new_ik; } // Adjust methods to recover missing data. They need addresses for // interpreter entry points and their default native method address // must be reset. // Updating methods must be done under a lock so multiple // threads don't update these in parallel // // Shared classes are all currently loaded by either the bootstrap or // internal parallel class loaders, so this will never cause a deadlock // on a custom class loader lock. ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader()); { HandleMark hm(THREAD); Handle lockObject = compute_loader_lock_object(class_loader, THREAD); check_loader_lock_contention(lockObject, THREAD); ObjectLocker ol(lockObject, THREAD, true); // prohibited package check assumes all classes loaded from archive call // restore_unshareable_info which calls ik->set_package() ik->restore_unshareable_info(loader_data, protection_domain, CHECK_NULL); } ik->print_class_load_logging(loader_data, NULL, NULL); // For boot loader, ensure that GetSystemPackage knows that a class in this // package was loaded. if (class_loader.is_null()) { int path_index = ik->shared_classpath_index(); ResourceMark rm; ClassLoader::add_package(ik->name()->as_C_string(), path_index, THREAD); } if (DumpLoadedClassList != NULL && classlist_file->is_open()) { // Only dump the classes that can be stored into CDS archive if (SystemDictionaryShared::is_sharing_possible(loader_data)) { ResourceMark rm(THREAD); classlist_file->print_cr("%s", ik->name()->as_C_string()); classlist_file->flush(); } } // notify a class loaded from shared object ClassLoadingService::notify_class_loaded(ik, true /* shared class */); } ik->set_has_passed_fingerprint_check(false); if (UseAOT && ik->supers_have_passed_fingerprint_checks()) { uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik); uint64_t cds_fp = ik->get_stored_fingerprint(); if (aot_fp != 0 && aot_fp == cds_fp) { // This class matches with a class saved in an AOT library ik->set_has_passed_fingerprint_check(true); } else { ResourceMark rm; log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp); } } return ik; } void SystemDictionary::clear_invoke_method_table() { SymbolPropertyEntry* spe = NULL; for (int index = 0; index < _invoke_method_table->table_size(); index++) { SymbolPropertyEntry* p = _invoke_method_table->bucket(index); while (p != NULL) { spe = p; p = p->next(); _invoke_method_table->free_entry(spe); } } } #endif // INCLUDE_CDS InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) { if (class_loader.is_null()) { ResourceMark rm; PackageEntry* pkg_entry = NULL; bool search_only_bootloader_append = false; ClassLoaderData *loader_data = class_loader_data(class_loader); // Find the package in the boot loader's package entry table. TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK_NULL); if (pkg_name != NULL) { pkg_entry = loader_data->packages()->lookup_only(pkg_name); } // Prior to attempting to load the class, enforce the boot loader's // visibility boundaries. if (!Universe::is_module_initialized()) { // During bootstrapping, prior to module initialization, any // class attempting to be loaded must be checked against the // java.base packages in the boot loader's PackageEntryTable. // No class outside of java.base is allowed to be loaded during // this bootstrapping window. if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) { // Class is either in the unnamed package or in // a named package within the unnamed module. Either // case is outside of java.base, do not attempt to // load the class post java.base definition. If // java.base has not been defined, let the class load // and its package will be checked later by // ModuleEntryTable::verify_javabase_packages. if (ModuleEntryTable::javabase_defined()) { return NULL; } } else { // Check that the class' package is defined within java.base. ModuleEntry* mod_entry = pkg_entry->module(); Symbol* mod_entry_name = mod_entry->name(); if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) { return NULL; } } } else { // After the module system has been initialized, check if the class' // package is in a module defined to the boot loader. if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) { // Class is either in the unnamed package, in a named package // within a module not defined to the boot loader or in a // a named package within the unnamed module. In all cases, // limit visibility to search for the class only in the boot // loader's append path. search_only_bootloader_append = true; } } // Prior to bootstrapping's module initialization, never load a class outside // of the boot loader's module path assert(Universe::is_module_initialized() || !search_only_bootloader_append, "Attempt to load a class outside of boot loader's module path"); // Search the shared system dictionary for classes preloaded into the // shared spaces. InstanceKlass* k = NULL; { #if INCLUDE_CDS PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time()); k = load_shared_class(class_name, class_loader, THREAD); #endif } if (k == NULL) { // Use VM class loader PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time()); k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL); } // find_or_define_instance_class may return a different InstanceKlass if (k != NULL) { InstanceKlass* defined_k = find_or_define_instance_class(class_name, class_loader, k, THREAD); if (!HAS_PENDING_EXCEPTION && defined_k != k) { // If a parallel capable class loader already defined this class, register 'k' for cleanup. assert(defined_k != NULL, "Should have a klass if there's no exception"); loader_data->add_to_deallocate_list(k); k = defined_k; } else if (HAS_PENDING_EXCEPTION) { loader_data->add_to_deallocate_list(k); return NULL; } } return k; } else { // Use user specified class loader to load class. Call loadClass operation on class_loader. ResourceMark rm(THREAD); assert(THREAD->is_Java_thread(), "must be a JavaThread"); JavaThread* jt = (JavaThread*) THREAD; PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(), ClassLoader::perf_app_classload_selftime(), ClassLoader::perf_app_classload_count(), jt->get_thread_stat()->perf_recursion_counts_addr(), jt->get_thread_stat()->perf_timers_addr(), PerfClassTraceTime::CLASS_LOAD); Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL); // Translate to external class name format, i.e., convert '/' chars to '.' Handle string = java_lang_String::externalize_classname(s, CHECK_NULL); JavaValue result(T_OBJECT); InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass(); // Call public unsynchronized loadClass(String) directly for all class loaders. // For parallelCapable class loaders, JDK >=7, loadClass(String, boolean) will // acquire a class-name based lock rather than the class loader object lock. // JDK < 7 already acquire the class loader lock in loadClass(String, boolean). JavaCalls::call_virtual(&result, class_loader, spec_klass, vmSymbols::loadClass_name(), vmSymbols::string_class_signature(), string, CHECK_NULL); assert(result.get_type() == T_OBJECT, "just checking"); oop obj = (oop) result.get_jobject(); // Primitive classes return null since forName() can not be // used to obtain any of the Class objects representing primitives or void if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) { InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj)); // For user defined Java class loaders, check that the name returned is // the same as that requested. This check is done for the bootstrap // loader when parsing the class file. if (class_name == k->name()) { return k; } } // Class is not found or has the wrong name, return NULL return NULL; } } void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) { HandleMark hm(THREAD); ClassLoaderData* loader_data = k->class_loader_data(); Handle class_loader_h(THREAD, loader_data->class_loader()); // for bootstrap and other parallel classloaders don't acquire lock, // use placeholder token // If a parallelCapable class loader calls define_instance_class instead of // find_or_define_instance_class to get here, we have a timing // hole with systemDictionary updates and check_constraints if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) { assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, compute_loader_lock_object(class_loader_h, THREAD)), "define called without lock"); } // Check class-loading constraints. Throw exception if violation is detected. // Grabs and releases SystemDictionary_lock // The check_constraints/find_class call and update_dictionary sequence // must be "atomic" for a specific class/classloader pair so we never // define two different instanceKlasses for that class/classloader pair. // Existing classloaders will call define_instance_class with the // classloader lock held // Parallel classloaders will call find_or_define_instance_class // which will require a token to perform the define class Symbol* name_h = k->name(); Dictionary* dictionary = loader_data->dictionary(); unsigned int d_hash = dictionary->compute_hash(name_h); check_constraints(d_hash, k, class_loader_h, true, CHECK); // Register class just loaded with class loader (placed in Vector) // Note we do this before updating the dictionary, as this can // fail with an OutOfMemoryError (if it does, we will *not* put this // class in the dictionary and will not update the class hierarchy). // JVMTI FollowReferences needs to find the classes this way. if (k->class_loader() != NULL) { methodHandle m(THREAD, Universe::loader_addClass_method()); JavaValue result(T_VOID); JavaCallArguments args(class_loader_h); args.push_oop(Handle(THREAD, k->java_mirror())); JavaCalls::call(&result, m, &args, CHECK); } // Add the new class. We need recompile lock during update of CHA. { unsigned int p_hash = placeholders()->compute_hash(name_h); int p_index = placeholders()->hash_to_index(p_hash); MutexLocker mu_r(Compile_lock, THREAD); // Add to class hierarchy, initialize vtables, and do possible // deoptimizations. add_to_hierarchy(k, CHECK); // No exception, but can block // Add to systemDictionary - so other classes can see it. // Grabs and releases SystemDictionary_lock update_dictionary(d_hash, p_index, p_hash, k, class_loader_h, THREAD); } k->eager_initialize(THREAD); // notify jvmti if (JvmtiExport::should_post_class_load()) { assert(THREAD->is_Java_thread(), "thread->is_Java_thread()"); JvmtiExport::post_class_load((JavaThread *) THREAD, k); } class_define_event(k, loader_data); } // Support parallel classloading // All parallel class loaders, including bootstrap classloader // lock a placeholder entry for this class/class_loader pair // to allow parallel defines of different classes for this class loader // With AllowParallelDefine flag==true, in case they do not synchronize around // FindLoadedClass/DefineClass, calls, we check for parallel // loading for them, wait if a defineClass is in progress // and return the initial requestor's results // This flag does not apply to the bootstrap classloader. // With AllowParallelDefine flag==false, call through to define_instance_class // which will throw LinkageError: duplicate class definition. // False is the requested default. // For better performance, the class loaders should synchronize // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they // potentially waste time reading and parsing the bytestream. // Note: VM callers should ensure consistency of k/class_name,class_loader // Be careful when modifying this code: once you have run // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS), // you need to find_and_remove it before returning. // So be careful to not exit with a CHECK_ macro betweeen these calls. InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader, InstanceKlass* k, TRAPS) { Symbol* name_h = k->name(); // passed in class_name may be null ClassLoaderData* loader_data = class_loader_data(class_loader); Dictionary* dictionary = loader_data->dictionary(); unsigned int d_hash = dictionary->compute_hash(name_h); // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS unsigned int p_hash = placeholders()->compute_hash(name_h); int p_index = placeholders()->hash_to_index(p_hash); PlaceholderEntry* probe; { MutexLocker mu(SystemDictionary_lock, THREAD); // First check if class already defined if (is_parallelDefine(class_loader)) { InstanceKlass* check = find_class(d_hash, name_h, dictionary); if (check != NULL) { return check; } } // Acquire define token for this class/classloader probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD); // Wait if another thread defining in parallel // All threads wait - even those that will throw duplicate class: otherwise // caller is surprised by LinkageError: duplicate, but findLoadedClass fails // if other thread has not finished updating dictionary while (probe->definer() != NULL) { SystemDictionary_lock->wait(); } // Only special cases allow parallel defines and can use other thread's results // Other cases fall through, and may run into duplicate defines // caught by finding an entry in the SystemDictionary if (is_parallelDefine(class_loader) && (probe->instance_klass() != NULL)) { placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD); SystemDictionary_lock->notify_all(); #ifdef ASSERT InstanceKlass* check = find_class(d_hash, name_h, dictionary); assert(check != NULL, "definer missed recording success"); #endif return probe->instance_klass(); } else { // This thread will define the class (even if earlier thread tried and had an error) probe->set_definer(THREAD); } } define_instance_class(k, THREAD); Handle linkage_exception = Handle(); // null handle // definer must notify any waiting threads { MutexLocker mu(SystemDictionary_lock, THREAD); PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data); assert(probe != NULL, "DEFINE_CLASS placeholder lost?"); if (probe != NULL) { if (HAS_PENDING_EXCEPTION) { linkage_exception = Handle(THREAD,PENDING_EXCEPTION); CLEAR_PENDING_EXCEPTION; } else { probe->set_instance_klass(k); } probe->set_definer(NULL); placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD); SystemDictionary_lock->notify_all(); } } // Can't throw exception while holding lock due to rank ordering if (linkage_exception() != NULL) { THROW_OOP_(linkage_exception(), NULL); // throws exception and returns } return k; } Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) { // If class_loader is NULL we synchronize on _system_loader_lock_obj if (class_loader.is_null()) { return Handle(THREAD, _system_loader_lock_obj); } else { return class_loader; } } // This method is added to check how often we have to wait to grab loader // lock. The results are being recorded in the performance counters defined in // ClassLoader::_sync_systemLoaderLockContentionRate and // ClassLoader::_sync_nonSystemLoaderLockConteionRate. void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) { if (!UsePerfData) { return; } assert(!loader_lock.is_null(), "NULL lock object"); if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock) == ObjectSynchronizer::owner_other) { // contention will likely happen, so increment the corresponding // contention counter. if (oopDesc::equals(loader_lock(), _system_loader_lock_obj)) { ClassLoader::sync_systemLoaderLockContentionRate()->inc(); } else { ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc(); } } } // ---------------------------------------------------------------------------- // Lookup InstanceKlass* SystemDictionary::find_class(unsigned int hash, Symbol* class_name, Dictionary* dictionary) { assert_locked_or_safepoint(SystemDictionary_lock); int index = dictionary->hash_to_index(hash); return dictionary->find_class(index, hash, class_name); } // Basic find on classes in the midst of being loaded Symbol* SystemDictionary::find_placeholder(Symbol* class_name, ClassLoaderData* loader_data) { assert_locked_or_safepoint(SystemDictionary_lock); unsigned int p_hash = placeholders()->compute_hash(class_name); int p_index = placeholders()->hash_to_index(p_hash); return placeholders()->find_entry(p_index, p_hash, class_name, loader_data); } // Used for assertions and verification only // Precalculating the hash and index is an optimization because there are many lookups // before adding the class. InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) { assert_locked_or_safepoint(SystemDictionary_lock); #ifndef ASSERT guarantee(VerifyBeforeGC || VerifyDuringGC || VerifyBeforeExit || VerifyDuringStartup || VerifyAfterGC, "too expensive"); #endif Dictionary* dictionary = loader_data->dictionary(); unsigned int d_hash = dictionary->compute_hash(class_name); return find_class(d_hash, class_name, dictionary); } // ---------------------------------------------------------------------------- // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in // before a new class is used. void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) { assert(k != NULL, "just checking"); assert_locked_or_safepoint(Compile_lock); // Link into hierachy. Make sure the vtables are initialized before linking into k->append_to_sibling_list(); // add to superklass/sibling list k->process_interfaces(THREAD); // handle all "implements" declarations k->set_init_state(InstanceKlass::loaded); // Now flush all code that depended on old class hierarchy. // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97) // Also, first reinitialize vtable because it may have gotten out of synch // while the new class wasn't connected to the class hierarchy. CodeCache::flush_dependents_on(k); } // ---------------------------------------------------------------------------- // GC support void SystemDictionary::always_strong_oops_do(OopClosure* blk) { roots_oops_do(blk, NULL); } #ifdef ASSERT class VerifySDReachableAndLiveClosure : public OopClosure { private: BoolObjectClosure* _is_alive; template void do_oop_work(T* p) { oop obj = RawAccess<>::oop_load(p); guarantee(_is_alive->do_object_b(obj), "Oop in protection domain cache table must be live"); } public: VerifySDReachableAndLiveClosure(BoolObjectClosure* is_alive) : OopClosure(), _is_alive(is_alive) { } virtual void do_oop(oop* p) { do_oop_work(p); } virtual void do_oop(narrowOop* p) { do_oop_work(p); } }; #endif // Assumes classes in the SystemDictionary are only unloaded at a safepoint // Note: anonymous classes are not in the SD. bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive, GCTimer* gc_timer, bool do_cleaning) { { GCTraceTime(Debug, gc, phases) t("SystemDictionary WeakHandle cleaning", gc_timer); vm_weak_oop_storage()->weak_oops_do(is_alive, &do_nothing_cl); } bool unloading_occurred; { GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer); // First, mark for unload all ClassLoaderData referencing a dead class loader. unloading_occurred = ClassLoaderDataGraph::do_unloading(is_alive, do_cleaning); } if (unloading_occurred) { GCTraceTime(Debug, gc, phases) t("Dictionary", gc_timer); constraints()->purge_loader_constraints(); resolution_errors()->purge_resolution_errors(); } { GCTraceTime(Debug, gc, phases) t("ProtectionDomainCacheTable", gc_timer); // Oops referenced by the protection domain cache table may get unreachable independently // of the class loader (eg. cached protection domain oops). So we need to // explicitly unlink them here. _pd_cache_table->unlink(is_alive); #ifdef ASSERT VerifySDReachableAndLiveClosure cl(is_alive); _pd_cache_table->oops_do(&cl); #endif } if (do_cleaning) { GCTraceTime(Debug, gc, phases) t("ResolvedMethodTable", gc_timer); ResolvedMethodTable::unlink(is_alive); } return unloading_occurred; } void SystemDictionary::roots_oops_do(OopClosure* strong, OopClosure* weak) { strong->do_oop(&_java_system_loader); strong->do_oop(&_java_platform_loader); strong->do_oop(&_system_loader_lock_obj); CDS_ONLY(SystemDictionaryShared::roots_oops_do(strong);) // Do strong roots marking if the closures are the same. if (strong == weak || !ClassUnloading) { // Only the protection domain oops contain references into the heap. Iterate // over all of them. _pd_cache_table->oops_do(strong); vm_weak_oop_storage()->oops_do(strong); } else { if (weak != NULL) { _pd_cache_table->oops_do(weak); vm_weak_oop_storage()->oops_do(weak); } } // Visit extra methods invoke_method_table()->oops_do(strong); if (weak != NULL) { ResolvedMethodTable::oops_do(weak); } } void SystemDictionary::oops_do(OopClosure* f) { f->do_oop(&_java_system_loader); f->do_oop(&_java_platform_loader); f->do_oop(&_system_loader_lock_obj); CDS_ONLY(SystemDictionaryShared::oops_do(f);) // Only the protection domain oops contain references into the heap. Iterate // over all of them. _pd_cache_table->oops_do(f); // Visit extra methods invoke_method_table()->oops_do(f); ResolvedMethodTable::oops_do(f); vm_weak_oop_storage()->oops_do(f); } // CDS: scan and relocate all classes in the system dictionary. void SystemDictionary::classes_do(MetaspaceClosure* it) { ClassLoaderData::the_null_class_loader_data()->dictionary()->classes_do(it); } // CDS: scan and relocate all classes referenced by _well_known_klasses[]. void SystemDictionary::well_known_klasses_do(MetaspaceClosure* it) { for (int id = FIRST_WKID; id < WKID_LIMIT; id++) { it->push(well_known_klass_addr((WKID)id)); } } void SystemDictionary::methods_do(void f(Method*)) { // Walk methods in loaded classes ClassLoaderDataGraph::methods_do(f); // Walk method handle intrinsics invoke_method_table()->methods_do(f); } class RemoveClassesClosure : public CLDClosure { public: void do_cld(ClassLoaderData* cld) { if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) { cld->dictionary()->remove_classes_in_error_state(); } } }; void SystemDictionary::remove_classes_in_error_state() { ClassLoaderData::the_null_class_loader_data()->dictionary()->remove_classes_in_error_state(); RemoveClassesClosure rcc; ClassLoaderDataGraph::cld_do(&rcc); } // ---------------------------------------------------------------------------- // Lazily load klasses void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) { // if multiple threads calling this function, only one thread will load // the class. The other threads will find the loaded version once the // class is loaded. Klass* aos = _abstract_ownable_synchronizer_klass; if (aos == NULL) { Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK); // Force a fence to prevent any read before the write completes OrderAccess::fence(); _abstract_ownable_synchronizer_klass = InstanceKlass::cast(k); } } // ---------------------------------------------------------------------------- // Initialization void SystemDictionary::initialize(TRAPS) { // Allocate arrays _placeholders = new PlaceholderTable(_placeholder_table_size); _number_of_modifications = 0; _loader_constraints = new LoaderConstraintTable(_loader_constraint_size); _resolution_errors = new ResolutionErrorTable(_resolution_error_size); _invoke_method_table = new SymbolPropertyTable(_invoke_method_size); _pd_cache_table = new ProtectionDomainCacheTable(defaultProtectionDomainCacheSize); // Allocate private object used as system class loader lock _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK); // Initialize basic classes initialize_preloaded_classes(CHECK); } // Compact table of directions on the initialization of klasses: static const short wk_init_info[] = { #define WK_KLASS_INIT_INFO(name, symbol, option) \ ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \ << SystemDictionary::CEIL_LG_OPTION_LIMIT) \ | (int)SystemDictionary::option ), WK_KLASSES_DO(WK_KLASS_INIT_INFO) #undef WK_KLASS_INIT_INFO 0 }; bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) { assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob"); int info = wk_init_info[id - FIRST_WKID]; int sid = (info >> CEIL_LG_OPTION_LIMIT); Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid); InstanceKlass** klassp = &_well_known_klasses[id]; bool must_load; #if INCLUDE_JVMCI if (EnableJVMCI) { // If JVMCI is enabled we require its classes to be found. must_load = (init_opt < SystemDictionary::Opt) || (init_opt == SystemDictionary::Jvmci); } else #endif { must_load = (init_opt < SystemDictionary::Opt); } if ((*klassp) == NULL) { Klass* k; if (must_load) { k = resolve_or_fail(symbol, true, CHECK_0); // load required class } else { k = resolve_or_null(symbol, CHECK_0); // load optional klass } (*klassp) = (k == NULL) ? NULL : InstanceKlass::cast(k); } return ((*klassp) != NULL); } void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) { assert((int)start_id <= (int)limit_id, "IDs are out of order!"); for (int id = (int)start_id; id < (int)limit_id; id++) { assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob"); int info = wk_init_info[id - FIRST_WKID]; int sid = (info >> CEIL_LG_OPTION_LIMIT); int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT)); initialize_wk_klass((WKID)id, opt, CHECK); } // move the starting value forward to the limit: start_id = limit_id; } void SystemDictionary::initialize_preloaded_classes(TRAPS) { assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once"); // Create the ModuleEntry for java.base. This call needs to be done here, // after vmSymbols::initialize() is called but before any classes are pre-loaded. ClassLoader::classLoader_init2(CHECK); // Preload commonly used klasses WKID scan = FIRST_WKID; // first do Object, then String, Class #if INCLUDE_CDS if (UseSharedSpaces) { initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK); // Initialize the constant pool for the Object_class Object_klass()->constants()->restore_unshareable_info(CHECK); initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK); } else #endif { initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK); } // Calculate offsets for String and Class classes since they are loaded and // can be used after this point. java_lang_String::compute_offsets(); java_lang_Class::compute_offsets(); // Fixup mirrors for classes loaded before java.lang.Class. // These calls iterate over the objects currently in the perm gen // so calling them at this point is matters (not before when there // are fewer objects and not later after there are more objects // in the perm gen. Universe::initialize_basic_type_mirrors(CHECK); Universe::fixup_mirrors(CHECK); // do a bunch more: initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK); // Preload ref klasses and set reference types InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER); InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass)); initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK); InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT); InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK); InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL); InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM); initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(ReferenceQueue_klass), scan, CHECK); // JSR 292 classes WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass); WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass); initialize_wk_klasses_until(jsr292_group_start, scan, CHECK); initialize_wk_klasses_through(jsr292_group_end, scan, CHECK); initialize_wk_klasses_until(NOT_JVMCI(WKID_LIMIT) JVMCI_ONLY(FIRST_JVMCI_WKID), scan, CHECK); _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass); _box_klasses[T_CHAR] = WK_KLASS(Character_klass); _box_klasses[T_FLOAT] = WK_KLASS(Float_klass); _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass); _box_klasses[T_BYTE] = WK_KLASS(Byte_klass); _box_klasses[T_SHORT] = WK_KLASS(Short_klass); _box_klasses[T_INT] = WK_KLASS(Integer_klass); _box_klasses[T_LONG] = WK_KLASS(Long_klass); //_box_klasses[T_OBJECT] = WK_KLASS(object_klass); //_box_klasses[T_ARRAY] = WK_KLASS(object_klass); { // Compute whether we should use checkPackageAccess or NOT Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature()); _has_checkPackageAccess = (method != NULL); } } // Tells if a given klass is a box (wrapper class, such as java.lang.Integer). // If so, returns the basic type it holds. If not, returns T_OBJECT. BasicType SystemDictionary::box_klass_type(Klass* k) { assert(k != NULL, ""); for (int i = T_BOOLEAN; i < T_VOID+1; i++) { if (_box_klasses[i] == k) return (BasicType)i; } return T_OBJECT; } // Constraints on class loaders. The details of the algorithm can be // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is // that the dictionary needs to maintain a set of contraints that // must be satisfied by all classes in the dictionary. // if defining is true, then LinkageError if already in dictionary // if initiating loader, then ok if InstanceKlass matches existing entry void SystemDictionary::check_constraints(unsigned int d_hash, InstanceKlass* k, Handle class_loader, bool defining, TRAPS) { ResourceMark rm(THREAD); stringStream ss; bool throwException = false; const char *linkage_error1 = NULL; const char *linkage_error2 = NULL; const char *linkage_error3 = ""; // Remember the loader of the similar class that is already loaded. const char *existing_klass_loader_name = ""; { Symbol* name = k->name(); ClassLoaderData *loader_data = class_loader_data(class_loader); MutexLocker mu(SystemDictionary_lock, THREAD); InstanceKlass* check = find_class(d_hash, name, loader_data->dictionary()); if (check != NULL) { // If different InstanceKlass - duplicate class definition, // else - ok, class loaded by a different thread in parallel. // We should only have found it if it was done loading and ok to use. // The dictionary only holds instance classes, placeholders // also hold array classes. assert(check->is_instance_klass(), "noninstance in systemdictionary"); if ((defining == true) || (k != check)) { throwException = true; ss.print("loader %s", java_lang_ClassLoader::describe_external(class_loader())); ss.print(" attempted duplicate %s definition for %s.", k->external_kind(), k->external_name()); } else { return; } } #ifdef ASSERT Symbol* ph_check = find_placeholder(name, loader_data); assert(ph_check == NULL || ph_check == name, "invalid symbol"); #endif if (throwException == false) { if (constraints()->check_or_update(k, class_loader, name) == false) { throwException = true; ss.print("loader constraint violation: loader %s", java_lang_ClassLoader::describe_external(class_loader())); ss.print(" wants to load %s %s.", k->external_kind(), k->external_name()); Klass *existing_klass = constraints()->find_constrained_klass(name, class_loader); if (existing_klass->class_loader() != class_loader()) { ss.print(" A different %s with the same name was previously loaded by %s.", existing_klass->external_kind(), java_lang_ClassLoader::describe_external(existing_klass->class_loader())); } } } } // Throw error now if needed (cannot throw while holding // SystemDictionary_lock because of rank ordering) if (throwException == true) { THROW_MSG(vmSymbols::java_lang_LinkageError(), ss.as_string()); } } // Update class loader data dictionary - done after check_constraint and add_to_hierachy // have been called. void SystemDictionary::update_dictionary(unsigned int d_hash, int p_index, unsigned int p_hash, InstanceKlass* k, Handle class_loader, TRAPS) { // Compile_lock prevents systemDictionary updates during compilations assert_locked_or_safepoint(Compile_lock); Symbol* name = k->name(); ClassLoaderData *loader_data = class_loader_data(class_loader); { MutexLocker mu1(SystemDictionary_lock, THREAD); // See whether biased locking is enabled and if so set it for this // klass. // Note that this must be done past the last potential blocking // point / safepoint. We enable biased locking lazily using a // VM_Operation to iterate the SystemDictionary and installing the // biasable mark word into each InstanceKlass's prototype header. // To avoid race conditions where we accidentally miss enabling the // optimization for one class in the process of being added to the // dictionary, we must not safepoint after the test of // BiasedLocking::enabled(). if (UseBiasedLocking && BiasedLocking::enabled()) { // Set biased locking bit for all loaded classes; it will be // cleared if revocation occurs too often for this type // NOTE that we must only do this when the class is initally // defined, not each time it is referenced from a new class loader if (oopDesc::equals(k->class_loader(), class_loader())) { k->set_prototype_header(markOopDesc::biased_locking_prototype()); } } // Make a new dictionary entry. Dictionary* dictionary = loader_data->dictionary(); InstanceKlass* sd_check = find_class(d_hash, name, dictionary); if (sd_check == NULL) { dictionary->add_klass(d_hash, name, k); notice_modification(); } #ifdef ASSERT sd_check = find_class(d_hash, name, dictionary); assert (sd_check != NULL, "should have entry in dictionary"); // Note: there may be a placeholder entry: for circularity testing // or for parallel defines #endif SystemDictionary_lock->notify_all(); } } // Try to find a class name using the loader constraints. The // loader constraints might know about a class that isn't fully loaded // yet and these will be ignored. Klass* SystemDictionary::find_constrained_instance_or_array_klass( Symbol* class_name, Handle class_loader, TRAPS) { // First see if it has been loaded directly. // Force the protection domain to be null. (This removes protection checks.) Handle no_protection_domain; Klass* klass = find_instance_or_array_klass(class_name, class_loader, no_protection_domain, CHECK_NULL); if (klass != NULL) return klass; // Now look to see if it has been loaded elsewhere, and is subject to // a loader constraint that would require this loader to return the // klass that is already loaded. if (FieldType::is_array(class_name)) { // For array classes, their Klass*s are not kept in the // constraint table. The element Klass*s are. FieldArrayInfo fd; BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL)); if (t != T_OBJECT) { klass = Universe::typeArrayKlassObj(t); } else { MutexLocker mu(SystemDictionary_lock, THREAD); klass = constraints()->find_constrained_klass(fd.object_key(), class_loader); } // If element class already loaded, allocate array klass if (klass != NULL) { klass = klass->array_klass_or_null(fd.dimension()); } } else { MutexLocker mu(SystemDictionary_lock, THREAD); // Non-array classes are easy: simply check the constraint table. klass = constraints()->find_constrained_klass(class_name, class_loader); } return klass; } bool SystemDictionary::add_loader_constraint(Symbol* class_name, Handle class_loader1, Handle class_loader2, Thread* THREAD) { ClassLoaderData* loader_data1 = class_loader_data(class_loader1); ClassLoaderData* loader_data2 = class_loader_data(class_loader2); Symbol* constraint_name = NULL; if (!FieldType::is_array(class_name)) { constraint_name = class_name; } else { // For array classes, their Klass*s are not kept in the // constraint table. The element classes are. FieldArrayInfo fd; BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false)); // primitive types always pass if (t != T_OBJECT) { return true; } else { constraint_name = fd.object_key(); } } Dictionary* dictionary1 = loader_data1->dictionary(); unsigned int d_hash1 = dictionary1->compute_hash(constraint_name); Dictionary* dictionary2 = loader_data2->dictionary(); unsigned int d_hash2 = dictionary2->compute_hash(constraint_name); { MutexLocker mu_s(SystemDictionary_lock, THREAD); InstanceKlass* klass1 = find_class(d_hash1, constraint_name, dictionary1); InstanceKlass* klass2 = find_class(d_hash2, constraint_name, dictionary2); return constraints()->add_entry(constraint_name, klass1, class_loader1, klass2, class_loader2); } } // Add entry to resolution error table to record the error when the first // attempt to resolve a reference to a class has failed. void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which, Symbol* error, Symbol* message) { unsigned int hash = resolution_errors()->compute_hash(pool, which); int index = resolution_errors()->hash_to_index(hash); { MutexLocker ml(SystemDictionary_lock, Thread::current()); resolution_errors()->add_entry(index, hash, pool, which, error, message); } } // Delete a resolution error for RedefineClasses for a constant pool is going away void SystemDictionary::delete_resolution_error(ConstantPool* pool) { resolution_errors()->delete_entry(pool); } // Lookup resolution error table. Returns error if found, otherwise NULL. Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which, Symbol** message) { unsigned int hash = resolution_errors()->compute_hash(pool, which); int index = resolution_errors()->hash_to_index(hash); { MutexLocker ml(SystemDictionary_lock, Thread::current()); ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which); if (entry != NULL) { *message = entry->message(); return entry->error(); } else { return NULL; } } } // Signature constraints ensure that callers and callees agree about // the meaning of type names in their signatures. This routine is the // intake for constraints. It collects them from several places: // // * LinkResolver::resolve_method (if check_access is true) requires // that the resolving class (the caller) and the defining class of // the resolved method (the callee) agree on each type in the // method's signature. // // * LinkResolver::resolve_interface_method performs exactly the same // checks. // // * LinkResolver::resolve_field requires that the constant pool // attempting to link to a field agree with the field's defining // class about the type of the field signature. // // * klassVtable::initialize_vtable requires that, when a class // overrides a vtable entry allocated by a superclass, that the // overriding method (i.e., the callee) agree with the superclass // on each type in the method's signature. // // * klassItable::initialize_itable requires that, when a class fills // in its itables, for each non-abstract method installed in an // itable, the method (i.e., the callee) agree with the interface // on each type in the method's signature. // // All those methods have a boolean (check_access, checkconstraints) // which turns off the checks. This is used from specialized contexts // such as bootstrapping, dumping, and debugging. // // No direct constraint is placed between the class and its // supertypes. Constraints are only placed along linked relations // between callers and callees. When a method overrides or implements // an abstract method in a supertype (superclass or interface), the // constraints are placed as if the supertype were the caller to the // overriding method. (This works well, since callers to the // supertype have already established agreement between themselves and // the supertype.) As a result of all this, a class can disagree with // its supertype about the meaning of a type name, as long as that // class neither calls a relevant method of the supertype, nor is // called (perhaps via an override) from the supertype. // // // SystemDictionary::check_signature_loaders(sig, l1, l2) // // Make sure all class components (including arrays) in the given // signature will be resolved to the same class in both loaders. // Returns the name of the type that failed a loader constraint check, or // NULL if no constraint failed. No exception except OOME is thrown. // Arrays are not added to the loader constraint table, their elements are. Symbol* SystemDictionary::check_signature_loaders(Symbol* signature, Handle loader1, Handle loader2, bool is_method, TRAPS) { // Nothing to do if loaders are the same. if (oopDesc::equals(loader1(), loader2())) { return NULL; } SignatureStream sig_strm(signature, is_method); while (!sig_strm.is_done()) { if (sig_strm.is_object()) { Symbol* sig = sig_strm.as_symbol(CHECK_NULL); if (!add_loader_constraint(sig, loader1, loader2, THREAD)) { return sig; } } sig_strm.next(); } return NULL; } methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid, Symbol* signature, TRAPS) { methodHandle empty; assert(MethodHandles::is_signature_polymorphic(iid) && MethodHandles::is_signature_polymorphic_intrinsic(iid) && iid != vmIntrinsics::_invokeGeneric, "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid)); unsigned int hash = invoke_method_table()->compute_hash(signature, iid); int index = invoke_method_table()->hash_to_index(hash); SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid); methodHandle m; if (spe == NULL || spe->method() == NULL) { spe = NULL; // Must create lots of stuff here, but outside of the SystemDictionary lock. m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty)); if (!Arguments::is_interpreter_only()) { // Generate a compiled form of the MH intrinsic. AdapterHandlerLibrary::create_native_wrapper(m); // Check if have the compiled code. if (!m->has_compiled_code()) { THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(), "Out of space in CodeCache for method handle intrinsic", empty); } } // Now grab the lock. We might have to throw away the new method, // if a racing thread has managed to install one at the same time. { MutexLocker ml(SystemDictionary_lock, THREAD); spe = invoke_method_table()->find_entry(index, hash, signature, iid); if (spe == NULL) spe = invoke_method_table()->add_entry(index, hash, signature, iid); if (spe->method() == NULL) spe->set_method(m()); } } assert(spe != NULL && spe->method() != NULL, ""); assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() && spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()), "MH intrinsic invariant"); return spe->method(); } // Helper for unpacking the return value from linkMethod and linkCallSite. static methodHandle unpack_method_and_appendix(Handle mname, Klass* accessing_klass, objArrayHandle appendix_box, Handle* appendix_result, TRAPS) { methodHandle empty; if (mname.not_null()) { Method* m = java_lang_invoke_MemberName::vmtarget(mname()); if (m != NULL) { oop appendix = appendix_box->obj_at(0); if (TraceMethodHandles) { #ifndef PRODUCT ttyLocker ttyl; tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m)); m->print(); if (appendix != NULL) { tty->print("appendix = "); appendix->print(); } tty->cr(); #endif //PRODUCT } (*appendix_result) = Handle(THREAD, appendix); // the target is stored in the cpCache and if a reference to this // MemberName is dropped we need a way to make sure the // class_loader containing this method is kept alive. ClassLoaderData* this_key = accessing_klass->class_loader_data(); this_key->record_dependency(m->method_holder()); return methodHandle(THREAD, m); } } THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty); return empty; } methodHandle SystemDictionary::find_method_handle_invoker(Klass* klass, Symbol* name, Symbol* signature, Klass* accessing_klass, Handle *appendix_result, Handle *method_type_result, TRAPS) { methodHandle empty; assert(THREAD->can_call_java() ,""); Handle method_type = SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty)); int ref_kind = JVM_REF_invokeVirtual; oop name_oop = StringTable::intern(name, CHECK_(empty)); Handle name_str (THREAD, name_oop); objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty)); assert(appendix_box->obj_at(0) == NULL, ""); // This should not happen. JDK code should take care of that. if (accessing_klass == NULL || method_type.is_null()) { THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty); } // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName JavaCallArguments args; args.push_oop(Handle(THREAD, accessing_klass->java_mirror())); args.push_int(ref_kind); args.push_oop(Handle(THREAD, klass->java_mirror())); args.push_oop(name_str); args.push_oop(method_type); args.push_oop(appendix_box); JavaValue result(T_OBJECT); JavaCalls::call_static(&result, SystemDictionary::MethodHandleNatives_klass(), vmSymbols::linkMethod_name(), vmSymbols::linkMethod_signature(), &args, CHECK_(empty)); Handle mname(THREAD, (oop) result.get_jobject()); (*method_type_result) = method_type; return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD); } // Decide if we can globally cache a lookup of this class, to be returned to any client that asks. // We must ensure that all class loaders everywhere will reach this class, for any client. // This is a safe bet for public classes in java.lang, such as Object and String. // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types. // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util. static bool is_always_visible_class(oop mirror) { Klass* klass = java_lang_Class::as_Klass(mirror); if (klass->is_objArray_klass()) { klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type } if (klass->is_typeArray_klass()) { return true; // primitive array } assert(klass->is_instance_klass(), "%s", klass->external_name()); return klass->is_public() && (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke } // Return the Java mirror (java.lang.Class instance) for a single-character // descriptor. This result, when available, is the same as produced by the // heavier API point of the same name that takes a Symbol. oop SystemDictionary::find_java_mirror_for_type(char signature_char) { return java_lang_Class::primitive_mirror(char2type(signature_char)); } // Find or construct the Java mirror (java.lang.Class instance) for a // for the given field type signature, as interpreted relative to the // given class loader. Handles primitives, void, references, arrays, // and all other reflectable types, except method types. // N.B. Code in reflection should use this entry point. Handle SystemDictionary::find_java_mirror_for_type(Symbol* signature, Klass* accessing_klass, Handle class_loader, Handle protection_domain, SignatureStream::FailureMode failure_mode, TRAPS) { Handle empty; assert(accessing_klass == NULL || (class_loader.is_null() && protection_domain.is_null()), "one or the other, or perhaps neither"); Symbol* type = signature; // What we have here must be a valid field descriptor, // and all valid field descriptors are supported. // Produce the same java.lang.Class that reflection reports. if (type->utf8_length() == 1) { // It's a primitive. (Void has a primitive mirror too.) char ch = (char) type->byte_at(0); assert(is_java_primitive(char2type(ch)) || ch == 'V', ""); return Handle(THREAD, find_java_mirror_for_type(ch)); } else if (FieldType::is_obj(type) || FieldType::is_array(type)) { // It's a reference type. if (accessing_klass != NULL) { class_loader = Handle(THREAD, accessing_klass->class_loader()); protection_domain = Handle(THREAD, accessing_klass->protection_domain()); } Klass* constant_type_klass; if (failure_mode == SignatureStream::ReturnNull) { constant_type_klass = resolve_or_null(type, class_loader, protection_domain, CHECK_(empty)); } else { bool throw_error = (failure_mode == SignatureStream::NCDFError); constant_type_klass = resolve_or_fail(type, class_loader, protection_domain, throw_error, CHECK_(empty)); } if (constant_type_klass == NULL) { return Handle(); // report failure this way } Handle mirror(THREAD, constant_type_klass->java_mirror()); // Check accessibility, emulating ConstantPool::verify_constant_pool_resolve. if (accessing_klass != NULL) { Klass* sel_klass = constant_type_klass; bool fold_type_to_class = true; LinkResolver::check_klass_accessability(accessing_klass, sel_klass, fold_type_to_class, CHECK_(empty)); } return mirror; } // Fall through to an error. assert(false, "unsupported mirror syntax"); THROW_MSG_(vmSymbols::java_lang_InternalError(), "unsupported mirror syntax", empty); } // Ask Java code to find or construct a java.lang.invoke.MethodType for the given // signature, as interpreted relative to the given class loader. // Because of class loader constraints, all method handle usage must be // consistent with this loader. Handle SystemDictionary::find_method_handle_type(Symbol* signature, Klass* accessing_klass, TRAPS) { Handle empty; vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid); int index = invoke_method_table()->hash_to_index(hash); SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid); if (spe != NULL && spe->method_type() != NULL) { assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), ""); return Handle(THREAD, spe->method_type()); } else if (!THREAD->can_call_java()) { warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME return Handle(); // do not attempt from within compiler, unless it was cached } Handle class_loader, protection_domain; if (accessing_klass != NULL) { class_loader = Handle(THREAD, accessing_klass->class_loader()); protection_domain = Handle(THREAD, accessing_klass->protection_domain()); } bool can_be_cached = true; int npts = ArgumentCount(signature).size(); objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty)); int arg = 0; Handle rt; // the return type from the signature ResourceMark rm(THREAD); for (SignatureStream ss(signature); !ss.is_done(); ss.next()) { oop mirror = NULL; if (can_be_cached) { // Use neutral class loader to lookup candidate classes to be placed in the cache. mirror = ss.as_java_mirror(Handle(), Handle(), SignatureStream::ReturnNull, CHECK_(empty)); if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) { // Fall back to accessing_klass context. can_be_cached = false; } } if (!can_be_cached) { // Resolve, throwing a real error if it doesn't work. mirror = ss.as_java_mirror(class_loader, protection_domain, SignatureStream::NCDFError, CHECK_(empty)); } assert(mirror != NULL, "%s", ss.as_symbol(THREAD)->as_C_string()); if (ss.at_return_type()) rt = Handle(THREAD, mirror); else pts->obj_at_put(arg++, mirror); // Check accessibility. if (!java_lang_Class::is_primitive(mirror) && accessing_klass != NULL) { Klass* sel_klass = java_lang_Class::as_Klass(mirror); mirror = NULL; // safety // Emulate ConstantPool::verify_constant_pool_resolve. bool fold_type_to_class = true; LinkResolver::check_klass_accessability(accessing_klass, sel_klass, fold_type_to_class, CHECK_(empty)); } } assert(arg == npts, ""); // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType JavaCallArguments args(Handle(THREAD, rt())); args.push_oop(pts); JavaValue result(T_OBJECT); JavaCalls::call_static(&result, SystemDictionary::MethodHandleNatives_klass(), vmSymbols::findMethodHandleType_name(), vmSymbols::findMethodHandleType_signature(), &args, CHECK_(empty)); Handle method_type(THREAD, (oop) result.get_jobject()); if (can_be_cached) { // We can cache this MethodType inside the JVM. MutexLocker ml(SystemDictionary_lock, THREAD); spe = invoke_method_table()->find_entry(index, hash, signature, null_iid); if (spe == NULL) spe = invoke_method_table()->add_entry(index, hash, signature, null_iid); if (spe->method_type() == NULL) { spe->set_method_type(method_type()); } } // report back to the caller with the MethodType return method_type; } Handle SystemDictionary::find_field_handle_type(Symbol* signature, Klass* accessing_klass, TRAPS) { Handle empty; ResourceMark rm(THREAD); SignatureStream ss(signature, /*is_method=*/ false); if (!ss.is_done()) { Handle class_loader, protection_domain; if (accessing_klass != NULL) { class_loader = Handle(THREAD, accessing_klass->class_loader()); protection_domain = Handle(THREAD, accessing_klass->protection_domain()); } oop mirror = ss.as_java_mirror(class_loader, protection_domain, SignatureStream::NCDFError, CHECK_(empty)); ss.next(); if (ss.is_done()) { return Handle(THREAD, mirror); } } return empty; } // Ask Java code to find or construct a method handle constant. Handle SystemDictionary::link_method_handle_constant(Klass* caller, int ref_kind, //e.g., JVM_REF_invokeVirtual Klass* callee, Symbol* name, Symbol* signature, TRAPS) { Handle empty; if (caller == NULL) { THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty); } Handle name_str = java_lang_String::create_from_symbol(name, CHECK_(empty)); Handle signature_str = java_lang_String::create_from_symbol(signature, CHECK_(empty)); // Put symbolic info from the MH constant into freshly created MemberName and resolve it. Handle mname = MemberName_klass()->allocate_instance_handle(CHECK_(empty)); java_lang_invoke_MemberName::set_clazz(mname(), callee->java_mirror()); java_lang_invoke_MemberName::set_name (mname(), name_str()); java_lang_invoke_MemberName::set_type (mname(), signature_str()); java_lang_invoke_MemberName::set_flags(mname(), MethodHandles::ref_kind_to_flags(ref_kind)); if (ref_kind == JVM_REF_invokeVirtual && callee->name() == vmSymbols::java_lang_invoke_MethodHandle() && (name == vmSymbols::invoke_name() || name == vmSymbols::invokeExact_name())) { // Skip resolution for j.l.i.MethodHandle.invoke()/invokeExact(). // They are public signature polymorphic methods, but require appendix argument // which MemberName resolution doesn't handle. There's special logic on JDK side to handle them // (see MethodHandles.linkMethodHandleConstant() and MethodHandles.findVirtualForMH()). } else { MethodHandles::resolve_MemberName(mname, caller, /*speculative_resolve*/false, CHECK_(empty)); } // After method/field resolution succeeded, it's safe to resolve MH signature as well. Handle type = MethodHandles::resolve_MemberName_type(mname, caller, CHECK_(empty)); // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle JavaCallArguments args; args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class args.push_int(ref_kind); args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class args.push_oop(name_str); args.push_oop(type); JavaValue result(T_OBJECT); JavaCalls::call_static(&result, SystemDictionary::MethodHandleNatives_klass(), vmSymbols::linkMethodHandleConstant_name(), vmSymbols::linkMethodHandleConstant_signature(), &args, CHECK_(empty)); return Handle(THREAD, (oop) result.get_jobject()); } // Ask Java to compute a constant by invoking a BSM given a Dynamic_info CP entry Handle SystemDictionary::link_dynamic_constant(Klass* caller, int condy_index, Handle bootstrap_specifier, Symbol* name, Symbol* type, TRAPS) { Handle empty; Handle bsm, info; if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) { bsm = bootstrap_specifier; } else { assert(bootstrap_specifier->is_objArray(), ""); objArrayOop args = (objArrayOop) bootstrap_specifier(); assert(args->length() == 2, ""); bsm = Handle(THREAD, args->obj_at(0)); info = Handle(THREAD, args->obj_at(1)); } guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()), "caller must supply a valid BSM"); // This should not happen. JDK code should take care of that. if (caller == NULL) { THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad dynamic constant", empty); } Handle constant_name = java_lang_String::create_from_symbol(name, CHECK_(empty)); // Resolve the constant type in the context of the caller class Handle type_mirror = find_java_mirror_for_type(type, caller, SignatureStream::NCDFError, CHECK_(empty)); // call java.lang.invoke.MethodHandleNatives::linkConstantDyanmic(caller, condy_index, bsm, type, info) JavaCallArguments args; args.push_oop(Handle(THREAD, caller->java_mirror())); args.push_int(condy_index); args.push_oop(bsm); args.push_oop(constant_name); args.push_oop(type_mirror); args.push_oop(info); JavaValue result(T_OBJECT); JavaCalls::call_static(&result, SystemDictionary::MethodHandleNatives_klass(), vmSymbols::linkDynamicConstant_name(), vmSymbols::linkDynamicConstant_signature(), &args, CHECK_(empty)); return Handle(THREAD, (oop) result.get_jobject()); } // Ask Java code to find or construct a java.lang.invoke.CallSite for the given // name and signature, as interpreted relative to the given class loader. methodHandle SystemDictionary::find_dynamic_call_site_invoker(Klass* caller, int indy_index, Handle bootstrap_specifier, Symbol* name, Symbol* type, Handle *appendix_result, Handle *method_type_result, TRAPS) { methodHandle empty; Handle bsm, info; if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) { bsm = bootstrap_specifier; } else { objArrayOop args = (objArrayOop) bootstrap_specifier(); assert(args->length() == 2, ""); bsm = Handle(THREAD, args->obj_at(0)); info = Handle(THREAD, args->obj_at(1)); } guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()), "caller must supply a valid BSM"); Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty)); Handle method_type = find_method_handle_type(type, caller, CHECK_(empty)); // This should not happen. JDK code should take care of that. if (caller == NULL || method_type.is_null()) { THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty); } objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty)); assert(appendix_box->obj_at(0) == NULL, ""); // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, indy_index, bsm, name, mtype, info, &appendix) JavaCallArguments args; args.push_oop(Handle(THREAD, caller->java_mirror())); args.push_int(indy_index); args.push_oop(bsm); args.push_oop(method_name); args.push_oop(method_type); args.push_oop(info); args.push_oop(appendix_box); JavaValue result(T_OBJECT); JavaCalls::call_static(&result, SystemDictionary::MethodHandleNatives_klass(), vmSymbols::linkCallSite_name(), vmSymbols::linkCallSite_signature(), &args, CHECK_(empty)); Handle mname(THREAD, (oop) result.get_jobject()); (*method_type_result) = method_type; return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD); } // Protection domain cache table handling ProtectionDomainCacheEntry* SystemDictionary::cache_get(Handle protection_domain) { return _pd_cache_table->get(protection_domain); } #if INCLUDE_CDS void SystemDictionary::reorder_dictionary_for_sharing() { ClassLoaderData::the_null_class_loader_data()->dictionary()->reorder_dictionary_for_sharing(); } #endif size_t SystemDictionary::count_bytes_for_buckets() { return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_buckets(); } size_t SystemDictionary::count_bytes_for_table() { return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_table(); } void SystemDictionary::copy_buckets(char* top, char* end) { ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_buckets(top, end); } void SystemDictionary::copy_table(char* top, char* end) { ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_table(top, end); } // ---------------------------------------------------------------------------- void SystemDictionary::print_shared(outputStream *st) { shared_dictionary()->print_on(st); } void SystemDictionary::print_on(outputStream *st) { if (shared_dictionary() != NULL) { st->print_cr("Shared Dictionary"); shared_dictionary()->print_on(st); st->cr(); } GCMutexLocker mu(SystemDictionary_lock); ClassLoaderDataGraph::print_dictionary(st); // Placeholders placeholders()->print_on(st); st->cr(); // loader constraints - print under SD_lock constraints()->print_on(st); st->cr(); _pd_cache_table->print_on(st); st->cr(); } void SystemDictionary::verify() { guarantee(constraints() != NULL, "Verify of loader constraints failed"); guarantee(placeholders()->number_of_entries() >= 0, "Verify of placeholders failed"); GCMutexLocker mu(SystemDictionary_lock); // Verify dictionary ClassLoaderDataGraph::verify_dictionary(); placeholders()->verify(); // Verify constraint table guarantee(constraints() != NULL, "Verify of loader constraints failed"); constraints()->verify(placeholders()); _pd_cache_table->verify(); } void SystemDictionary::dump(outputStream *st, bool verbose) { assert_locked_or_safepoint(SystemDictionary_lock); if (verbose) { print_on(st); } else { if (shared_dictionary() != NULL) { shared_dictionary()->print_table_statistics(st, "Shared Dictionary"); } ClassLoaderDataGraph::print_dictionary_statistics(st); placeholders()->print_table_statistics(st, "Placeholder Table"); constraints()->print_table_statistics(st, "LoaderConstraints Table"); _pd_cache_table->print_table_statistics(st, "ProtectionDomainCache Table"); } } // Utility for dumping dictionaries. SystemDictionaryDCmd::SystemDictionaryDCmd(outputStream* output, bool heap) : DCmdWithParser(output, heap), _verbose("-verbose", "Dump the content of each dictionary entry for all class loaders", "BOOLEAN", false, "false") { _dcmdparser.add_dcmd_option(&_verbose); } void SystemDictionaryDCmd::execute(DCmdSource source, TRAPS) { VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSysDict, _verbose.value()); VMThread::execute(&dumper); } int SystemDictionaryDCmd::num_arguments() { ResourceMark rm; SystemDictionaryDCmd* dcmd = new SystemDictionaryDCmd(NULL, false); if (dcmd != NULL) { DCmdMark mark(dcmd); return dcmd->_dcmdparser.num_arguments(); } else { return 0; } } class CombineDictionariesClosure : public CLDClosure { private: Dictionary* _master_dictionary; public: CombineDictionariesClosure(Dictionary* master_dictionary) : _master_dictionary(master_dictionary) {} void do_cld(ClassLoaderData* cld) { ResourceMark rm; if (cld->is_anonymous()) { return; } if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) { for (int i = 0; i < cld->dictionary()->table_size(); ++i) { Dictionary* curr_dictionary = cld->dictionary(); DictionaryEntry* p = curr_dictionary->bucket(i); while (p != NULL) { Symbol* name = p->instance_klass()->name(); unsigned int d_hash = _master_dictionary->compute_hash(name); int d_index = _master_dictionary->hash_to_index(d_hash); DictionaryEntry* next = p->next(); if (p->literal()->class_loader_data() != cld) { // This is an initiating class loader entry; don't use it log_trace(cds)("Skipping initiating cl entry: %s", name->as_C_string()); curr_dictionary->free_entry(p); } else { log_trace(cds)("Moved to boot dictionary: %s", name->as_C_string()); curr_dictionary->unlink_entry(p); p->set_pd_set(NULL); // pd_set is runtime only information and will be reconstructed. _master_dictionary->add_entry(d_index, p); } p = next; } *curr_dictionary->bucket_addr(i) = NULL; } } } }; // Combining platform and system loader dictionaries into boot loader dictionary. // During run time, we only have one shared dictionary. void SystemDictionary::combine_shared_dictionaries() { assert(DumpSharedSpaces, "dump time only"); // If AppCDS isn't enabled, we only dump the classes in the boot loader dictionary // into the shared archive. if (UseAppCDS) { Dictionary* master_dictionary = ClassLoaderData::the_null_class_loader_data()->dictionary(); CombineDictionariesClosure cdc(master_dictionary); ClassLoaderDataGraph::cld_do(&cdc); } // These tables are no longer valid or necessary. Keeping them around will // cause SystemDictionary::verify() to fail. Let's empty them. _placeholders = new PlaceholderTable(_placeholder_table_size); _loader_constraints = new LoaderConstraintTable(_loader_constraint_size); NOT_PRODUCT(SystemDictionary::verify()); } // Caller needs ResourceMark. const char* SystemDictionary::loader_name(const oop loader) { return ((loader) == NULL ? "" : InstanceKlass::cast((loader)->klass())->name()->as_C_string()); } // caller needs ResourceMark const char* SystemDictionary::loader_name(const ClassLoaderData* loader_data) { return (loader_data->class_loader() == NULL ? "" : SystemDictionary::loader_name(loader_data->class_loader())); } void SystemDictionary::initialize_oop_storage() { _vm_weak_oop_storage = new OopStorage("VM Weak Oop Handles", VMWeakAlloc_lock, VMWeakActive_lock); } OopStorage* SystemDictionary::vm_weak_oop_storage() { assert(_vm_weak_oop_storage != NULL, "Uninitialized"); return _vm_weak_oop_storage; }