Mercurial > hg > truffle
view src/share/vm/classfile/systemDictionary.cpp @ 3273:df22fe9c5a93
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author | coleenp |
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date | Wed, 27 Apr 2011 17:25:45 -0700 |
parents | 8ce625481709 |
children | 167b70ff3abc |
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/* * Copyright (c) 1997, 2011, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. * */ #include "precompiled.hpp" #include "classfile/dictionary.hpp" #include "classfile/javaClasses.hpp" #include "classfile/loaderConstraints.hpp" #include "classfile/placeholders.hpp" #include "classfile/resolutionErrors.hpp" #include "classfile/systemDictionary.hpp" #include "classfile/vmSymbols.hpp" #include "interpreter/bytecodeStream.hpp" #include "interpreter/interpreter.hpp" #include "memory/gcLocker.hpp" #include "memory/oopFactory.hpp" #include "oops/instanceKlass.hpp" #include "oops/instanceRefKlass.hpp" #include "oops/klass.inline.hpp" #include "oops/methodDataOop.hpp" #include "oops/objArrayKlass.hpp" #include "oops/oop.inline.hpp" #include "oops/oop.inline2.hpp" #include "oops/typeArrayKlass.hpp" #include "prims/jvmtiEnvBase.hpp" #include "prims/methodHandles.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/signature.hpp" #include "services/classLoadingService.hpp" #include "services/threadService.hpp" Dictionary* SystemDictionary::_dictionary = NULL; 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; int SystemDictionary::_number_of_modifications = 0; oop SystemDictionary::_system_loader_lock_obj = NULL; klassOop SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT] = { NULL /*, NULL...*/ }; klassOop SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ }; oop SystemDictionary::_java_system_loader = NULL; bool SystemDictionary::_has_loadClassInternal = false; bool SystemDictionary::_has_checkPackageAccess = false; // lazily initialized klass variables volatile klassOop SystemDictionary::_abstract_ownable_synchronizer_klass = NULL; // ---------------------------------------------------------------------------- // Java-level SystemLoader oop SystemDictionary::java_system_loader() { return _java_system_loader; } void SystemDictionary::compute_java_system_loader(TRAPS) { KlassHandle system_klass(THREAD, WK_KLASS(ClassLoader_klass)); JavaValue result(T_OBJECT); JavaCalls::call_static(&result, KlassHandle(THREAD, WK_KLASS(ClassLoader_klass)), vmSymbols::getSystemClassLoader_name(), vmSymbols::void_classloader_signature(), CHECK); _java_system_loader = (oop)result.get_jobject(); } // ---------------------------------------------------------------------------- // debugging #ifdef ASSERT // return true if class_name contains no '.' (internal format is '/') bool SystemDictionary::is_internal_format(Symbol* class_name) { if (class_name != NULL) { ResourceMark rm; char* name = class_name->as_C_string(); return strchr(name, '.') == NULL; } else { return true; } } #endif // ---------------------------------------------------------------------------- // Parallel class loading check bool SystemDictionary::is_parallelCapable(Handle class_loader) { if (UnsyncloadClass || class_loader.is_null()) return true; if (AlwaysLockClassLoader) return false; return java_lang_Class::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_Class::parallelCapable(class_loader())) { return true; } return false; } // ---------------------------------------------------------------------------- // Resolving of classes // Forwards to resolve_or_null klassOop SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) { klassOop klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD); if (HAS_PENDING_EXCEPTION || klass == NULL) { KlassHandle k_h(THREAD, klass); // can return a null klass klass = handle_resolution_exception(class_name, class_loader, protection_domain, throw_error, k_h, THREAD); } return klass; } klassOop SystemDictionary::handle_resolution_exception(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, KlassHandle klass_h, 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_h() == NULL, "Should not have result with exception pending"); Handle e(THREAD, PENDING_EXCEPTION); CLEAR_PENDING_EXCEPTION; THROW_MSG_CAUSE_0(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_h() == NULL) { ResourceMark rm(THREAD); if (throw_error) { THROW_MSG_0(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string()); } else { THROW_MSG_0(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string()); } } return (klassOop)klass_h(); } klassOop 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 klassOop SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) { assert(!THREAD->is_Compiler_thread(), "Can not load classes with the Compiler thread"); if (FieldType::is_array(class_name)) { return resolve_array_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL); } 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, CHECK_NULL); } else { return resolve_instance_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL); } } klassOop SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) { return resolve_or_null(class_name, Handle(), Handle(), THREAD); } // Forwards to resolve_instance_class_or_null klassOop 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"); klassOop 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 = Klass::cast(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. klassOop SystemDictionary::resolve_super_or_fail(Symbol* child_name, Symbol* class_name, Handle class_loader, Handle protection_domain, bool is_superclass, TRAPS) { // Try to get one of the well-known klasses. // They are trusted, and do not participate in circularities. if (LinkWellKnownClasses) { klassOop k = find_well_known_klass(class_name); if (k != NULL) { return k; } } // 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 system 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 in the heap needs to be in the system 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 // compute_hash can have a safepoint unsigned int d_hash = dictionary()->compute_hash(child_name, class_loader); int d_index = dictionary()->hash_to_index(d_hash); unsigned int p_hash = placeholders()->compute_hash(child_name, class_loader); 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); klassOop childk = find_class(d_index, d_hash, child_name, class_loader); klassOop 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 = instanceKlass::cast(childk)->super()) != NULL) && ((Klass::cast(quicksuperk)->name() == class_name) && (Klass::cast(quicksuperk)->class_loader() == class_loader()))) { return quicksuperk; } else { PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, class_loader); if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) { throw_circularity_error = true; } } if (!throw_circularity_error) { PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, class_loader, PlaceholderTable::LOAD_SUPER, class_name, THREAD); } } if (throw_circularity_error) { ResourceMark rm(THREAD); THROW_MSG_0(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 klassOop superk = NULL; superk = SystemDictionary::resolve_or_null(class_name, class_loader, protection_domain, THREAD); KlassHandle superk_h(THREAD, superk); // Note: clean up of placeholders currently in callers of // resolve_super_or_fail - either at update_dictionary time // or on error { MutexLocker mu(SystemDictionary_lock, THREAD); PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, class_loader); if (probe != NULL) { probe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER); } } if (HAS_PENDING_EXCEPTION || superk_h() == NULL) { // can null superk superk_h = KlassHandle(THREAD, handle_resolution_exception(class_name, class_loader, protection_domain, true, superk_h, THREAD)); } return superk_h(); } void SystemDictionary::validate_protection_domain(instanceKlassHandle 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); if (TraceProtectionDomainVerification) { // Print out trace information tty->print_cr("Checking package access"); tty->print(" - class loader: "); class_loader()->print_value_on(tty); tty->cr(); tty->print(" - protection domain: "); protection_domain()->print_value_on(tty); tty->cr(); tty->print(" - loading: "); klass()->print_value_on(tty); tty->cr(); } assert(class_loader() != NULL, "should not have non-null protection domain for null classloader"); KlassHandle system_loader(THREAD, SystemDictionary::ClassLoader_klass()); JavaCalls::call_special(&result, class_loader, system_loader, vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature(), Handle(THREAD, klass->java_mirror()), protection_domain, THREAD); if (TraceProtectionDomainVerification) { if (HAS_PENDING_EXCEPTION) { tty->print_cr(" -> DENIED !!!!!!!!!!!!!!!!!!!!!"); } else { tty->print_cr(" -> granted"); } tty->cr(); } 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. { // We recalculate the entry here -- we've called out to java since // the last time it was calculated. Symbol* kn = klass->name(); unsigned int d_hash = dictionary()->compute_hash(kn, class_loader); int d_index = dictionary()->hash_to_index(d_hash); MutexLocker mu(SystemDictionary_lock, THREAD); { // Note that we have an entry, and entries can be deleted only during GC, // so we cannot allow GC to occur while we're holding this entry. // We're using a No_Safepoint_Verifier to catch any place where we // might potentially do a GC at all. // SystemDictionary::do_unloading() asserts that classes are only // unloaded at a safepoint. No_Safepoint_Verifier nosafepoint; dictionary()->add_protection_domain(d_index, d_hash, klass, class_loader, 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) UnsyncloadClass not set // 3) 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((!(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: only one thread can define the class, but multiple can resolve // 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 klassOop if other thread has completed load // and we are done, // If return null klassOop and no pending exception, the caller must load the class instanceKlassHandle SystemDictionary::handle_parallel_super_load( Symbol* name, Symbol* superclassname, Handle class_loader, Handle protection_domain, Handle lockObject, TRAPS) { instanceKlassHandle nh = instanceKlassHandle(); // null Handle unsigned int d_hash = dictionary()->compute_hash(name, class_loader); int d_index = dictionary()->hash_to_index(d_hash); unsigned int p_hash = placeholders()->compute_hash(name, class_loader); 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. klassOop superk = SystemDictionary::resolve_super_or_fail(name, superclassname, class_loader, protection_domain, true, CHECK_(nh)); // We don't redefine the class, so we just need to clean up if there // was not an error (don't want to modify any system dictionary // data structures). { MutexLocker mu(SystemDictionary_lock, THREAD); placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD); SystemDictionary_lock->notify_all(); } // 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 klassOop check = find_class(d_index, d_hash, name, class_loader); if (check != NULL) { // Klass is already loaded, so just return it return(instanceKlassHandle(THREAD, check)); } else { return nh; } } // 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 klassOop check = find_class(d_index, d_hash, name, class_loader); if (check != NULL) { // Klass is already loaded, so just return it return(instanceKlassHandle(THREAD, check)); } else { placeholder = placeholders()->get_entry(p_index, p_hash, name, class_loader); if (placeholder && placeholder->super_load_in_progress() ){ // Before UnsyncloadClass: // 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 (nh); } klassOop 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"); // UseNewReflection // Fix for 4474172; see evaluation for more details class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader())); // Do lookup to see if class already exist and the protection domain // has the right access unsigned int d_hash = dictionary()->compute_hash(name, class_loader); int d_index = dictionary()->hash_to_index(d_hash); klassOop probe = dictionary()->find(d_index, d_hash, name, class_loader, protection_domain, THREAD); 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, // or all classloaders with UnsyncloadClass do not acquire lock here bool DoObjectLock = true; if (is_parallelCapable(class_loader)) { DoObjectLock = false; } unsigned int p_hash = placeholders()->compute_hash(name, class_loader); 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; instanceKlassHandle k; PlaceholderEntry* placeholder; Symbol* superclassname = NULL; { MutexLocker mu(SystemDictionary_lock, THREAD); klassOop check = find_class(d_index, d_hash, name, class_loader); if (check != NULL) { // Klass is already loaded, so just return it class_has_been_loaded = true; k = instanceKlassHandle(THREAD, check); } else { placeholder = placeholders()->get_entry(p_index, p_hash, name, class_loader); if (placeholder && placeholder->super_load_in_progress()) { super_load_in_progress = true; if (placeholder->havesupername() == true) { superclassname = placeholder->supername(); havesupername = true; } } } } // If the class in is in the placeholder table, class loading is in progress if (super_load_in_progress && havesupername==true) { k = SystemDictionary::handle_parallel_super_load(name, superclassname, class_loader, protection_domain, lockObject, THREAD); if (HAS_PENDING_EXCEPTION) { return NULL; } if (!k.is_null()) { class_has_been_loaded = true; } } if (!class_has_been_loaded) { // 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. UnsyncloadClass - don't use objectLocker // With this flag, we allow parallel classloading of a // class/classloader pair // case4. 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 5. parallelCapable user level classloaders - without objectLocker // Allow parallel classloading of a class/classloader pair bool throw_circularity_error = false; { MutexLocker mu(SystemDictionary_lock, THREAD); if (class_loader.is_null() || !is_parallelCapable(class_loader)) { PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, class_loader); 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 4: 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 klassOop check = find_class(d_index, d_hash, name, class_loader); if (check != NULL) { // Klass is already loaded, so just return it k = instanceKlassHandle(THREAD, 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, class_loader); } } } } // All cases: add LOAD_INSTANCE // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try // LOAD_INSTANCE in parallel // add placeholder entry even if error - callers will remove on error if (!throw_circularity_error && !class_has_been_loaded) { PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, class_loader, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD); // 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 klassOop check = find_class(d_index, d_hash, name, class_loader); if (check != NULL) { // Klass is already loaded, so just return it k = instanceKlassHandle(THREAD, check); class_has_been_loaded = true; newprobe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE); placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD); SystemDictionary_lock->notify_all(); } } } // must throw error outside of owning lock if (throw_circularity_error) { ResourceMark rm(THREAD); THROW_MSG_0(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string()); } if (!class_has_been_loaded) { // Do actual loading k = load_instance_class(name, class_loader, THREAD); // For UnsyncloadClass only // If they got a linkageError, check if a parallel class load succeeded. // If it did, then for bytecode resolution the specification requires // that we return the same result we did for the other thread, i.e. the // successfully loaded instanceKlass // Should not get here for classloaders that support parallelism // with the new cleaner mechanism, even with AllowParallelDefineClass // Bootstrap goes through here to allow for an extra guarantee check if (UnsyncloadClass || (class_loader.is_null())) { if (k.is_null() && HAS_PENDING_EXCEPTION && PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass())) { MutexLocker mu(SystemDictionary_lock, THREAD); klassOop check = find_class(d_index, d_hash, name, class_loader); if (check != NULL) { // Klass is already loaded, so just use it k = instanceKlassHandle(THREAD, check); CLEAR_PENDING_EXCEPTION; guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?"); } } } // clean up placeholder entries for success or error // This cleans up LOAD_INSTANCE entries // It also cleans up LOAD_SUPER entries on errors from // calling load_instance_class { MutexLocker mu(SystemDictionary_lock, THREAD); PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name, class_loader); if (probe != NULL) { probe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE); placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD); SystemDictionary_lock->notify_all(); } } // 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.is_null() && k->class_loader() != class_loader()) { check_constraints(d_index, 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_index, 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()); } } } if (HAS_PENDING_EXCEPTION || k.is_null()) { // On error, clean up placeholders { MutexLocker mu(SystemDictionary_lock, THREAD); placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD); SystemDictionary_lock->notify_all(); } return NULL; } } } #ifdef ASSERT { Handle loader (THREAD, k->class_loader()); MutexLocker mu(SystemDictionary_lock, THREAD); oop kk = find_class(name, loader); 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 { MutexLocker mu(SystemDictionary_lock, THREAD); // Note that we have an entry, and entries can be deleted only during GC, // so we cannot allow GC to occur while we're holding this entry. // We're using a No_Safepoint_Verifier to catch any place where we // might potentially do a GC at all. // SystemDictionary::do_unloading() asserts that classes are only // unloaded at a safepoint. No_Safepoint_Verifier nosafepoint; if (dictionary()->is_valid_protection_domain(d_index, d_hash, name, class_loader, protection_domain)) { return k(); } } // Verify protection domain. If it fails an exception is thrown validate_protection_domain(k, class_loader, protection_domain, CHECK_(klassOop(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. klassOop SystemDictionary::find(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) { // UseNewReflection // 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())); unsigned int d_hash = dictionary()->compute_hash(class_name, class_loader); int d_index = dictionary()->hash_to_index(d_hash); { // Note that we have an entry, and entries can be deleted only during GC, // so we cannot allow GC to occur while we're holding this entry. // We're using a No_Safepoint_Verifier to catch any place where we // might potentially do a GC at all. // SystemDictionary::do_unloading() asserts that classes are only // unloaded at a safepoint. No_Safepoint_Verifier nosafepoint; return dictionary()->find(d_index, d_hash, class_name, class_loader, protection_domain, THREAD); } } // Look for a loaded instance or array klass by name. Do not do any loading. // return NULL in case of error. klassOop SystemDictionary::find_instance_or_array_klass(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) { klassOop k = NULL; assert(class_name != NULL, "class name must be non NULL"); // Try to get one of the well-known klasses. if (LinkWellKnownClasses) { k = find_well_known_klass(class_name); if (k != NULL) { return k; } } 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 = Klass::cast(k)->array_klass_or_null(fd.dimension()); } } else { k = find(class_name, class_loader, protection_domain, THREAD); } return k; } // Quick range check for names of well-known classes: static Symbol* wk_klass_name_limits[2] = {NULL, NULL}; #ifndef PRODUCT static int find_wkk_calls, find_wkk_probes, find_wkk_wins; // counts for "hello world": 3983, 1616, 1075 // => 60% hit after limit guard, 25% total win rate #endif klassOop SystemDictionary::find_well_known_klass(Symbol* class_name) { // A bounds-check on class_name will quickly get a negative result. NOT_PRODUCT(find_wkk_calls++); if (class_name >= wk_klass_name_limits[0] && class_name <= wk_klass_name_limits[1]) { NOT_PRODUCT(find_wkk_probes++); vmSymbols::SID sid = vmSymbols::find_sid(class_name); if (sid != vmSymbols::NO_SID) { klassOop k = NULL; switch (sid) { #define WK_KLASS_CASE(name, symbol, ignore_option) \ case vmSymbols::VM_SYMBOL_ENUM_NAME(symbol): \ k = WK_KLASS(name); break; WK_KLASSES_DO(WK_KLASS_CASE) #undef WK_KLASS_CASE } NOT_PRODUCT(if (k != NULL) find_wkk_wins++); return k; } } return NULL; } // Note: this method is much like resolve_from_stream, but // updates no supplemental data structures. // TODO consolidate the two methods with a helper routine? klassOop SystemDictionary::parse_stream(Symbol* class_name, Handle class_loader, Handle protection_domain, ClassFileStream* st, KlassHandle host_klass, GrowableArray<Handle>* cp_patches, TRAPS) { TempNewSymbol parsed_name = NULL; // Parse the stream. Note that we do this even though this klass might // already be present in the SystemDictionary, otherwise we would not // throw potential ClassFormatErrors. // // Note: "name" is updated. // Further note: a placeholder will be added for this class when // super classes are loaded (resolve_super_or_fail). We expect this // to be called for all classes but java.lang.Object; and we preload // java.lang.Object through resolve_or_fail, not this path. instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name, class_loader, protection_domain, host_klass, cp_patches, parsed_name, true, THREAD); // We don't redefine the class, so we just need to clean up whether there // was an error or not (don't want to modify any system dictionary // data structures). // Parsed name could be null if we threw an error before we got far // enough along to parse it -- in that case, there is nothing to clean up. if (parsed_name != NULL) { unsigned int p_hash = placeholders()->compute_hash(parsed_name, class_loader); int p_index = placeholders()->hash_to_index(p_hash); { MutexLocker mu(SystemDictionary_lock, THREAD); placeholders()->find_and_remove(p_index, p_hash, parsed_name, class_loader, THREAD); SystemDictionary_lock->notify_all(); } } if (host_klass.not_null() && k.not_null()) { assert(EnableInvokeDynamic, ""); // If it's anonymous, initialize it now, since nobody else will. k->set_host_klass(host_klass()); { 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 system dictionary. } 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()); } } 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. klassOop SystemDictionary::resolve_from_stream(Symbol* class_name, Handle class_loader, Handle protection_domain, ClassFileStream* st, bool verify, TRAPS) { // Classloaders that support parallelism, e.g. bootstrap classloader, // or all classloaders with UnsyncloadClass do not acquire lock here bool DoObjectLock = true; if (is_parallelCapable(class_loader)) { DoObjectLock = false; } // 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); TempNewSymbol parsed_name = NULL; // Parse the stream. Note that we do this even though this klass might // already be present in the SystemDictionary, otherwise we would not // throw potential ClassFormatErrors. // // Note: "name" is updated. // Further note: a placeholder will be added for this class when // super classes are loaded (resolve_super_or_fail). We expect this // to be called for all classes but java.lang.Object; and we preload // java.lang.Object through resolve_or_fail, not this path. instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name, class_loader, protection_domain, parsed_name, verify, THREAD); const char* pkg = "java/"; if (!HAS_PENDING_EXCEPTION && !class_loader.is_null() && parsed_name != NULL && !strncmp((const char*)parsed_name->bytes(), pkg, strlen(pkg))) { // It is illegal to define classes in the "java." package from // JVM_DefineClass or jni_DefineClass unless you're the bootclassloader ResourceMark rm(THREAD); char* name = parsed_name->as_C_string(); char* index = strrchr(name, '/'); *index = '\0'; // chop to just the package name while ((index = strchr(name, '/')) != NULL) { *index = '.'; // replace '/' with '.' in package name } const char* fmt = "Prohibited package name: %s"; size_t len = strlen(fmt) + strlen(name); char* message = NEW_RESOURCE_ARRAY(char, len); jio_snprintf(message, len, fmt, name); Exceptions::_throw_msg(THREAD_AND_LOCATION, vmSymbols::java_lang_SecurityException(), message); } if (!HAS_PENDING_EXCEPTION) { assert(parsed_name != NULL, "Sanity"); assert(class_name == NULL || class_name == parsed_name, "name mismatch"); // Verification prevents us from creating names with dots in them, this // asserts that that's the case. assert(is_internal_format(parsed_name), "external class name format used internally"); // 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)) { k = find_or_define_instance_class(class_name, class_loader, k, THREAD); } else { define_instance_class(k, THREAD); } } // If parsing the class file or define_instance_class failed, we // need to remove the placeholder added on our behalf. But we // must make sure parsed_name is valid first (it won't be if we had // a format error before the class was parsed far enough to // find the name). if (HAS_PENDING_EXCEPTION && parsed_name != NULL) { unsigned int p_hash = placeholders()->compute_hash(parsed_name, class_loader); int p_index = placeholders()->hash_to_index(p_hash); { MutexLocker mu(SystemDictionary_lock, THREAD); placeholders()->find_and_remove(p_index, p_hash, parsed_name, class_loader, THREAD); SystemDictionary_lock->notify_all(); } return NULL; } // Make sure that we didn't leave a place holder in the // SystemDictionary; this is only done on success debug_only( { if (!HAS_PENDING_EXCEPTION) { assert(parsed_name != NULL, "parsed_name is still null?"); Symbol* h_name = k->name(); Handle h_loader (THREAD, k->class_loader()); MutexLocker mu(SystemDictionary_lock, THREAD); klassOop check = find_class(parsed_name, class_loader); assert(check == k(), "should be present in the dictionary"); klassOop check2 = find_class(h_name, h_loader); assert(check == check2, "name inconsistancy in SystemDictionary"); } } ); return k(); } void SystemDictionary::set_shared_dictionary(HashtableBucket* t, int length, int number_of_entries) { assert(length == _nof_buckets * sizeof(HashtableBucket), "bad shared dictionary size."); _shared_dictionary = new Dictionary(_nof_buckets, t, number_of_entries); } // If there is a shared dictionary, then find the entry for the // given shared system class, if any. klassOop SystemDictionary::find_shared_class(Symbol* class_name) { if (shared_dictionary() != NULL) { unsigned int d_hash = dictionary()->compute_hash(class_name, Handle()); int d_index = 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.] instanceKlassHandle SystemDictionary::load_shared_class( Symbol* class_name, Handle class_loader, TRAPS) { instanceKlassHandle ik (THREAD, find_shared_class(class_name)); return load_shared_class(ik, class_loader, THREAD); } // Note well! Changes to this method may affect oop access order // in the shared archive. Please take care to not make changes that // adversely affect cold start time by changing the oop access order // that is specified in dump.cpp MarkAndMoveOrderedReadOnly and // MarkAndMoveOrderedReadWrite closures. instanceKlassHandle SystemDictionary::load_shared_class( instanceKlassHandle ik, Handle class_loader, TRAPS) { assert(class_loader.is_null(), "non-null classloader for shared class?"); if (ik.not_null()) { instanceKlassHandle nh = instanceKlassHandle(); // null Handle Symbol* class_name = ik->name(); // Found the class, now load the superclass and interfaces. If they // are shared, add them to the main system dictionary and reset // their hierarchy references (supers, subs, and interfaces). if (ik->super() != NULL) { Symbol* cn = ik->super()->klass_part()->name(); resolve_super_or_fail(class_name, cn, class_loader, Handle(), true, CHECK_(nh)); } objArrayHandle interfaces (THREAD, ik->local_interfaces()); int num_interfaces = interfaces->length(); for (int index = 0; index < num_interfaces; index++) { klassOop k = klassOop(interfaces->obj_at(index)); // Note: can not use instanceKlass::cast here because // interfaces' instanceKlass's C++ vtbls haven't been // reinitialized yet (they will be once the interface classes // are loaded) Symbol* name = k->klass_part()->name(); resolve_super_or_fail(class_name, name, class_loader, Handle(), false, CHECK_(nh)); } // 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 the bootstrap // classloader, so this will never cause a deadlock on // a custom class loader lock. { Handle lockObject = compute_loader_lock_object(class_loader, THREAD); check_loader_lock_contention(lockObject, THREAD); ObjectLocker ol(lockObject, THREAD, true); objArrayHandle methods (THREAD, ik->methods()); int num_methods = methods->length(); for (int index2 = 0; index2 < num_methods; ++index2) { methodHandle m(THREAD, methodOop(methods->obj_at(index2))); m()->link_method(m, CHECK_(nh)); } if (JvmtiExport::has_redefined_a_class()) { // Reinitialize vtable because RedefineClasses may have changed some // entries in this vtable for super classes so the CDS vtable might // point to old or obsolete entries. RedefineClasses doesn't fix up // vtables in the shared system dictionary, only the main one. // It also redefines the itable too so fix that too. ResourceMark rm(THREAD); ik->vtable()->initialize_vtable(false, CHECK_(nh)); ik->itable()->initialize_itable(false, CHECK_(nh)); } } if (TraceClassLoading) { ResourceMark rm; tty->print("[Loaded %s", ik->external_name()); tty->print(" from shared objects file"); tty->print_cr("]"); } // notify a class loaded from shared object ClassLoadingService::notify_class_loaded(instanceKlass::cast(ik()), true /* shared class */); } return ik; } #ifdef KERNEL // Some classes on the bootstrap class path haven't been installed on the // system yet. Call the DownloadManager method to make them appear in the // bootstrap class path and try again to load the named class. // Note that with delegation class loaders all classes in another loader will // first try to call this so it'd better be fast!! static instanceKlassHandle download_and_retry_class_load( Symbol* class_name, TRAPS) { klassOop dlm = SystemDictionary::sun_jkernel_DownloadManager_klass(); instanceKlassHandle nk; // If download manager class isn't loaded just return. if (dlm == NULL) return nk; { HandleMark hm(THREAD); ResourceMark rm(THREAD); Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nk)); Handle class_string = java_lang_String::externalize_classname(s, CHECK_(nk)); // return value JavaValue result(T_OBJECT); // Call the DownloadManager. We assume that it has a lock because // multiple classes could be not found and downloaded at the same time. // class sun.misc.DownloadManager; // public static String getBootClassPathEntryForClass(String className); JavaCalls::call_static(&result, KlassHandle(THREAD, dlm), vmSymbols::getBootClassPathEntryForClass_name(), vmSymbols::string_string_signature(), class_string, CHECK_(nk)); // Get result.string and add to bootclasspath assert(result.get_type() == T_OBJECT, "just checking"); oop obj = (oop) result.get_jobject(); if (obj == NULL) { return nk; } Handle h_obj(THREAD, obj); char* new_class_name = java_lang_String::as_platform_dependent_str(h_obj, CHECK_(nk)); // lock the loader // we use this lock because JVMTI does. Handle loader_lock(THREAD, SystemDictionary::system_loader_lock()); ObjectLocker ol(loader_lock, THREAD); // add the file to the bootclasspath ClassLoader::update_class_path_entry_list(new_class_name, true); } // end HandleMark if (TraceClassLoading) { ClassLoader::print_bootclasspath(); } return ClassLoader::load_classfile(class_name, CHECK_(nk)); } #endif // KERNEL instanceKlassHandle SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) { instanceKlassHandle nh = instanceKlassHandle(); // null Handle if (class_loader.is_null()) { // Search the shared system dictionary for classes preloaded into the // shared spaces. instanceKlassHandle k; { PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time()); k = load_shared_class(class_name, class_loader, THREAD); } if (k.is_null()) { // Use VM class loader PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time()); k = ClassLoader::load_classfile(class_name, CHECK_(nh)); } #ifdef KERNEL // If the VM class loader has failed to load the class, call the // DownloadManager class to make it magically appear on the classpath // and try again. This is only configured with the Kernel VM. if (k.is_null()) { k = download_and_retry_class_load(class_name, CHECK_(nh)); } #endif // KERNEL // find_or_define_instance_class may return a different instanceKlass if (!k.is_null()) { k = find_or_define_instance_class(class_name, class_loader, k, CHECK_(nh)); } 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_(nh)); // Translate to external class name format, i.e., convert '/' chars to '.' Handle string = java_lang_String::externalize_classname(s, CHECK_(nh)); JavaValue result(T_OBJECT); KlassHandle spec_klass (THREAD, 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), // so the call to loadClassInternal() was not required. // // UnsyncloadClass flag means both call loadClass(String) and do // not acquire the class loader lock even for class loaders that are // not parallelCapable. This was a risky transitional // flag for diagnostic purposes only. It is risky to call // custom class loaders without synchronization. // WARNING If a custom class loader does NOT synchronizer findClass, or callers of // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field. // Do NOT assume this will be supported in future releases. // // Added MustCallLoadClassInternal in case we discover in the field // a customer that counts on this call if (MustCallLoadClassInternal && has_loadClassInternal()) { JavaCalls::call_special(&result, class_loader, spec_klass, vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature(), string, CHECK_(nh)); } else { JavaCalls::call_virtual(&result, class_loader, spec_klass, vmSymbols::loadClass_name(), vmSymbols::string_class_signature(), string, CHECK_(nh)); } 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))) { instanceKlassHandle k = instanceKlassHandle(THREAD, java_lang_Class::as_klassOop(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 nh; } } void SystemDictionary::define_instance_class(instanceKlassHandle k, TRAPS) { Handle class_loader_h(THREAD, k->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(); unsigned int d_hash = dictionary()->compute_hash(name_h, class_loader_h); int d_index = dictionary()->hash_to_index(d_hash); check_constraints(d_index, 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). 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, class_loader_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_index, 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()); } } // 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 instanceKlassHandle SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader, instanceKlassHandle k, TRAPS) { instanceKlassHandle nh = instanceKlassHandle(); // null Handle Symbol* name_h = k->name(); // passed in class_name may be null unsigned int d_hash = dictionary()->compute_hash(name_h, class_loader); int d_index = dictionary()->hash_to_index(d_hash); // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS unsigned int p_hash = placeholders()->compute_hash(name_h, class_loader); int p_index = placeholders()->hash_to_index(p_hash); PlaceholderEntry* probe; { MutexLocker mu(SystemDictionary_lock, THREAD); // First check if class already defined if (UnsyncloadClass || (is_parallelDefine(class_loader))) { klassOop check = find_class(d_index, d_hash, name_h, class_loader); if (check != NULL) { return(instanceKlassHandle(THREAD, check)); } } // Acquire define token for this class/classloader probe = placeholders()->find_and_add(p_index, p_hash, name_h, class_loader, 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 ((UnsyncloadClass || is_parallelDefine(class_loader)) && (probe->instanceKlass() != NULL)) { probe->remove_seen_thread(THREAD, PlaceholderTable::DEFINE_CLASS); placeholders()->find_and_remove(p_index, p_hash, name_h, class_loader, THREAD); SystemDictionary_lock->notify_all(); #ifdef ASSERT klassOop check = find_class(d_index, d_hash, name_h, class_loader); assert(check != NULL, "definer missed recording success"); #endif return(instanceKlassHandle(THREAD, probe->instanceKlass())); } 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, class_loader); 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_instanceKlass(k()); } probe->set_definer(NULL); probe->remove_seen_thread(THREAD, PlaceholderTable::DEFINE_CLASS); placeholders()->find_and_remove(p_index, p_hash, name_h, class_loader, THREAD); SystemDictionary_lock->notify_all(); } } // Can't throw exception while holding lock due to rank ordering if (linkage_exception() != NULL) { THROW_OOP_(linkage_exception(), nh); // 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 (loader_lock() == _system_loader_lock_obj) { ClassLoader::sync_systemLoaderLockContentionRate()->inc(); } else { ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc(); } } } // ---------------------------------------------------------------------------- // Lookup klassOop SystemDictionary::find_class(int index, unsigned int hash, Symbol* class_name, Handle class_loader) { assert_locked_or_safepoint(SystemDictionary_lock); assert (index == dictionary()->index_for(class_name, class_loader), "incorrect index?"); klassOop k = dictionary()->find_class(index, hash, class_name, class_loader); return k; } // Basic find on classes in the midst of being loaded Symbol* SystemDictionary::find_placeholder(Symbol* class_name, Handle class_loader) { assert_locked_or_safepoint(SystemDictionary_lock); unsigned int p_hash = placeholders()->compute_hash(class_name, class_loader); int p_index = placeholders()->hash_to_index(p_hash); return placeholders()->find_entry(p_index, p_hash, class_name, class_loader); } // Used for assertions and verification only klassOop SystemDictionary::find_class(Symbol* class_name, Handle class_loader) { #ifndef ASSERT guarantee(VerifyBeforeGC || VerifyDuringGC || VerifyBeforeExit || VerifyAfterGC, "too expensive"); #endif assert_locked_or_safepoint(SystemDictionary_lock); // First look in the loaded class array unsigned int d_hash = dictionary()->compute_hash(class_name, class_loader); int d_index = dictionary()->hash_to_index(d_hash); return find_class(d_index, d_hash, class_name, class_loader); } // Get the next class in the diictionary. klassOop SystemDictionary::try_get_next_class() { return dictionary()->try_get_next_class(); } // ---------------------------------------------------------------------------- // 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(instanceKlassHandle k, TRAPS) { assert(k.not_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. Universe::flush_dependents_on(k); } // ---------------------------------------------------------------------------- // GC support // Following roots during mark-sweep is separated in two phases. // // The first phase follows preloaded classes and all other system // classes, since these will never get unloaded anyway. // // The second phase removes (unloads) unreachable classes from the // system dictionary and follows the remaining classes' contents. void SystemDictionary::always_strong_oops_do(OopClosure* blk) { // Follow preloaded classes/mirrors and system loader object blk->do_oop(&_java_system_loader); preloaded_oops_do(blk); always_strong_classes_do(blk); } void SystemDictionary::always_strong_classes_do(OopClosure* blk) { // Follow all system classes and temporary placeholders in dictionary dictionary()->always_strong_classes_do(blk); // Placeholders. These are *always* strong roots, as they // represent classes we're actively loading. placeholders_do(blk); // Visit extra methods invoke_method_table()->oops_do(blk); } void SystemDictionary::placeholders_do(OopClosure* blk) { placeholders()->oops_do(blk); } bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive) { bool result = dictionary()->do_unloading(is_alive); constraints()->purge_loader_constraints(is_alive); resolution_errors()->purge_resolution_errors(is_alive); return result; } // The mirrors are scanned by shared_oops_do() which is // not called by oops_do(). In order to process oops in // a necessary order, shared_oops_do() is call by // Universe::oops_do(). void SystemDictionary::oops_do(OopClosure* f) { // Adjust preloaded classes and system loader object f->do_oop(&_java_system_loader); preloaded_oops_do(f); lazily_loaded_oops_do(f); // Adjust dictionary dictionary()->oops_do(f); // Visit extra methods invoke_method_table()->oops_do(f); // Partially loaded classes placeholders()->oops_do(f); // Adjust constraint table constraints()->oops_do(f); // Adjust resolution error table resolution_errors()->oops_do(f); } void SystemDictionary::preloaded_oops_do(OopClosure* f) { for (int k = (int)FIRST_WKID; k < (int)WKID_LIMIT; k++) { f->do_oop((oop*) &_well_known_klasses[k]); } { for (int i = 0; i < T_VOID+1; i++) { if (_box_klasses[i] != NULL) { assert(i >= T_BOOLEAN, "checking"); f->do_oop((oop*) &_box_klasses[i]); } } } // The basic type mirrors would have already been processed in // Universe::oops_do(), via a call to shared_oops_do(), so should // not be processed again. f->do_oop((oop*) &_system_loader_lock_obj); FilteredFieldsMap::klasses_oops_do(f); } void SystemDictionary::lazily_loaded_oops_do(OopClosure* f) { f->do_oop((oop*) &_abstract_ownable_synchronizer_klass); } // Just the classes from defining class loaders // Don't iterate over placeholders void SystemDictionary::classes_do(void f(klassOop)) { dictionary()->classes_do(f); } // Added for initialize_itable_for_klass // Just the classes from defining class loaders // Don't iterate over placeholders void SystemDictionary::classes_do(void f(klassOop, TRAPS), TRAPS) { dictionary()->classes_do(f, CHECK); } // All classes, and their class loaders // Don't iterate over placeholders void SystemDictionary::classes_do(void f(klassOop, oop)) { dictionary()->classes_do(f); } // All classes, and their class loaders // (added for helpers that use HandleMarks and ResourceMarks) // Don't iterate over placeholders void SystemDictionary::classes_do(void f(klassOop, oop, TRAPS), TRAPS) { dictionary()->classes_do(f, CHECK); } void SystemDictionary::placeholders_do(void f(Symbol*, oop)) { placeholders()->entries_do(f); } void SystemDictionary::methods_do(void f(methodOop)) { dictionary()->methods_do(f); invoke_method_table()->methods_do(f); } // ---------------------------------------------------------------------------- // Lazily load klasses void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) { assert(JDK_Version::is_gte_jdk16x_version(), "Must be JDK 1.6 or later"); // 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. klassOop aos = _abstract_ownable_synchronizer_klass; if (aos == NULL) { klassOop 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 = k; } } // ---------------------------------------------------------------------------- // Initialization void SystemDictionary::initialize(TRAPS) { // Allocate arrays assert(dictionary() == NULL, "SystemDictionary should only be initialized once"); _dictionary = new Dictionary(_nof_buckets); _placeholders = new PlaceholderTable(_nof_buckets); _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); // Allocate private object used as system class loader lock _system_loader_lock_obj = oopFactory::new_system_objArray(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); klassOop* klassp = &_well_known_klasses[id]; bool must_load = (init_opt < SystemDictionary::Opt); bool try_load = true; if (init_opt == SystemDictionary::Opt_Kernel) { #ifndef KERNEL try_load = false; #endif //KERNEL } if ((*klassp) == NULL && try_load) { if (must_load) { (*klassp) = resolve_or_fail(symbol, true, CHECK_0); // load required class } else { (*klassp) = resolve_or_null(symbol, CHECK_0); // load optional klass } } 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); // Update limits, so find_well_known_klass can be very fast: Symbol* s = vmSymbols::symbol_at((vmSymbols::SID)sid); if (wk_klass_name_limits[1] == NULL) { wk_klass_name_limits[0] = wk_klass_name_limits[1] = s; } else if (wk_klass_name_limits[1] < s) { wk_klass_name_limits[1] = s; } else if (wk_klass_name_limits[0] > s) { wk_klass_name_limits[0] = s; } } // 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"); // Preload commonly used klasses WKID scan = FIRST_WKID; // first do Object, String, Class initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK); debug_only(instanceKlass::verify_class_klass_nonstatic_oop_maps(WK_KLASS(Class_klass))); // 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); // JSR 292 classes WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass); WKID jsr292_group_end = WK_KLASS_ENUM_NAME(CallSite_klass); initialize_wk_klasses_until(jsr292_group_start, scan, CHECK); if (EnableInvokeDynamic) { initialize_wk_klasses_through(jsr292_group_end, scan, CHECK); } else { // Skip the JSR 292 classes, if not enabled. scan = WKID(jsr292_group_end + 1); } initialize_wk_klasses_until(WKID_LIMIT, 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); #ifdef KERNEL if (sun_jkernel_DownloadManager_klass() == NULL) { warning("Cannot find sun/jkernel/DownloadManager"); } #endif // KERNEL { // Compute whether we should use loadClass or loadClassInternal when loading classes. methodOop method = instanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature()); _has_loadClassInternal = (method != NULL); } { // Compute whether we should use checkPackageAccess or NOT methodOop 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(klassOop 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; } KlassHandle SystemDictionaryHandles::box_klass(BasicType t) { if (t >= T_BOOLEAN && t <= T_VOID) return KlassHandle(&SystemDictionary::_box_klasses[t], true); else return KlassHandle(); } // 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 system 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 systemDictionary // if initiating loader, then ok if instanceKlass matches existing entry void SystemDictionary::check_constraints(int d_index, unsigned int d_hash, instanceKlassHandle k, Handle class_loader, bool defining, TRAPS) { const char *linkage_error = NULL; { Symbol* name = k->name(); MutexLocker mu(SystemDictionary_lock, THREAD); klassOop check = find_class(d_index, d_hash, name, class_loader); if (check != (klassOop)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 // system dictionary only holds instance classes, placeholders // also holds array classes assert(check->klass_part()->oop_is_instance(), "noninstance in systemdictionary"); if ((defining == true) || (k() != check)) { linkage_error = "loader (instance of %s): attempted duplicate class " "definition for name: \"%s\""; } else { return; } } #ifdef ASSERT Symbol* ph_check = find_placeholder(name, class_loader); assert(ph_check == NULL || ph_check == name, "invalid symbol"); #endif if (linkage_error == NULL) { if (constraints()->check_or_update(k, class_loader, name) == false) { linkage_error = "loader constraint violation: loader (instance of %s)" " previously initiated loading for a different type with name \"%s\""; } } } // Throw error now if needed (cannot throw while holding // SystemDictionary_lock because of rank ordering) if (linkage_error) { ResourceMark rm(THREAD); const char* class_loader_name = loader_name(class_loader()); char* type_name = k->name()->as_C_string(); size_t buflen = strlen(linkage_error) + strlen(class_loader_name) + strlen(type_name); char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen); jio_snprintf(buf, buflen, linkage_error, class_loader_name, type_name); THROW_MSG(vmSymbols::java_lang_LinkageError(), buf); } } // Update system dictionary - done after check_constraint and add_to_hierachy // have been called. void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash, int p_index, unsigned int p_hash, instanceKlassHandle k, Handle class_loader, TRAPS) { // Compile_lock prevents systemDictionary updates during compilations assert_locked_or_safepoint(Compile_lock); Symbol* name = k->name(); { 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 (k->class_loader() == class_loader()) { k->set_prototype_header(markOopDesc::biased_locking_prototype()); } } // Check for a placeholder. If there, remove it and make a // new system dictionary entry. placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD); klassOop sd_check = find_class(d_index, d_hash, name, class_loader); if (sd_check == NULL) { dictionary()->add_klass(name, class_loader, k); notice_modification(); } #ifdef ASSERT sd_check = find_class(d_index, d_hash, name, class_loader); assert (sd_check != NULL, "should have entry in system dictionary"); // Changed to allow PH to remain to complete class circularity checking // while only one thread can define a class at one time, multiple // classes can resolve the superclass for a class at one time, // and the placeholder is used to track that // Symbol* ph_check = find_placeholder(name, class_loader); // assert (ph_check == NULL, "should not have a placeholder entry"); #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. klassOop 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; klassOop 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 klassOops are not kept in the // constraint table. The element klassOops 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::cast(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) { Symbol* constraint_name = NULL; if (!FieldType::is_array(class_name)) { constraint_name = class_name; } else { // For array classes, their klassOops 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(); } } unsigned int d_hash1 = dictionary()->compute_hash(constraint_name, class_loader1); int d_index1 = dictionary()->hash_to_index(d_hash1); unsigned int d_hash2 = dictionary()->compute_hash(constraint_name, class_loader2); int d_index2 = dictionary()->hash_to_index(d_hash2); { MutexLocker mu_s(SystemDictionary_lock, THREAD); // Better never do a GC while we're holding these oops No_Safepoint_Verifier nosafepoint; klassOop klass1 = find_class(d_index1, d_hash1, constraint_name, class_loader1); klassOop klass2 = find_class(d_index2, d_hash2, constraint_name, class_loader2); 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(constantPoolHandle pool, int which, Symbol* error) { 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); } } // Lookup resolution error table. Returns error if found, otherwise NULL. Symbol* SystemDictionary::find_resolution_error(constantPoolHandle pool, int which) { 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); return (entry != NULL) ? entry->error() : (Symbol*)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. The returned C string needs cleaning up // with a ResourceMark in the caller. No exception except OOME is thrown. // Arrays are not added to the loader constraint table, their elements are. char* SystemDictionary::check_signature_loaders(Symbol* signature, Handle loader1, Handle loader2, bool is_method, TRAPS) { // Nothing to do if loaders are the same. if (loader1() == loader2()) { return NULL; } ResourceMark rm(THREAD); SignatureStream sig_strm(signature, is_method); while (!sig_strm.is_done()) { if (sig_strm.is_object()) { Symbol* s = sig_strm.as_symbol(CHECK_NULL); Symbol* sig = s; if (!add_loader_constraint(sig, loader1, loader2, THREAD)) { return sig->as_C_string(); } } sig_strm.next(); } return NULL; } methodOop SystemDictionary::find_method_handle_invoke(Symbol* name, Symbol* signature, KlassHandle accessing_klass, TRAPS) { if (!EnableInvokeDynamic) return NULL; vmSymbols::SID name_id = vmSymbols::find_sid(name); assert(name_id != vmSymbols::NO_SID, "must be a known name"); unsigned int hash = invoke_method_table()->compute_hash(signature, name_id); int index = invoke_method_table()->hash_to_index(hash); SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, name_id); methodHandle non_cached_result; if (spe == NULL || spe->property_oop() == NULL) { spe = NULL; // Must create lots of stuff here, but outside of the SystemDictionary lock. if (THREAD->is_Compiler_thread()) return NULL; // do not attempt from within compiler bool for_invokeGeneric = (name_id != vmSymbols::VM_SYMBOL_ENUM_NAME(invokeExact_name)); bool found_on_bcp = false; Handle mt = find_method_handle_type(signature, accessing_klass, for_invokeGeneric, found_on_bcp, CHECK_NULL); KlassHandle mh_klass = SystemDictionaryHandles::MethodHandle_klass(); methodHandle m = methodOopDesc::make_invoke_method(mh_klass, name, signature, mt, CHECK_NULL); // 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. if (found_on_bcp) { MutexLocker ml(SystemDictionary_lock, Thread::current()); spe = invoke_method_table()->find_entry(index, hash, signature, name_id); if (spe == NULL) spe = invoke_method_table()->add_entry(index, hash, signature, name_id); if (spe->property_oop() == NULL) spe->set_property_oop(m()); } else { non_cached_result = m; } } if (spe != NULL && spe->property_oop() != NULL) { assert(spe->property_oop()->is_method(), ""); return (methodOop) spe->property_oop(); } else { return non_cached_result(); } } // 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, KlassHandle accessing_klass, bool for_invokeGeneric, bool& return_bcp_flag, TRAPS) { Handle class_loader, protection_domain; bool is_on_bcp = true; // keep this true as long as we can materialize from the boot classloader Handle empty; int npts = ArgumentCount(signature).size(); objArrayHandle pts = oopFactory::new_objArray(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 (is_on_bcp) { mirror = ss.as_java_mirror(class_loader, protection_domain, SignatureStream::ReturnNull, CHECK_(empty)); if (mirror == NULL) { // fall back from BCP to accessing_klass if (accessing_klass.not_null()) { class_loader = Handle(THREAD, instanceKlass::cast(accessing_klass())->class_loader()); protection_domain = Handle(THREAD, instanceKlass::cast(accessing_klass())->protection_domain()); } is_on_bcp = false; } } if (!is_on_bcp) { // Resolve, throwing a real error if it doesn't work. mirror = ss.as_java_mirror(class_loader, protection_domain, SignatureStream::NCDFError, CHECK_(empty)); } if (ss.at_return_type()) rt = Handle(THREAD, mirror); else pts->obj_at_put(arg++, mirror); // Check accessibility. if (ss.is_object() && accessing_klass.not_null()) { klassOop sel_klass = java_lang_Class::as_klassOop(mirror); // Emulate constantPoolOopDesc::verify_constant_pool_resolve. if (Klass::cast(sel_klass)->oop_is_objArray()) sel_klass = objArrayKlass::cast(sel_klass)->bottom_klass(); if (Klass::cast(sel_klass)->oop_is_instance()) { KlassHandle sel_kh(THREAD, sel_klass); LinkResolver::check_klass_accessability(accessing_klass, sel_kh, CHECK_(empty)); } } } assert(arg == npts, ""); // call java.lang.invoke.MethodHandleNatives::findMethodType(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 (for_invokeGeneric) { // call java.lang.invoke.MethodHandleNatives::notifyGenericMethodType(MethodType) -> void JavaCallArguments args(Handle(THREAD, method_type())); JavaValue no_result(T_VOID); JavaCalls::call_static(&no_result, SystemDictionary::MethodHandleNatives_klass(), vmSymbols::notifyGenericMethodType_name(), vmSymbols::notifyGenericMethodType_signature(), &args, THREAD); if (HAS_PENDING_EXCEPTION) { // If the notification fails, just kill it. CLEAR_PENDING_EXCEPTION; } } // report back to the caller with the MethodType and the "on_bcp" flag return_bcp_flag = is_on_bcp; return method_type; } // Ask Java code to find or construct a method handle constant. Handle SystemDictionary::link_method_handle_constant(KlassHandle caller, int ref_kind, //e.g., JVM_REF_invokeVirtual KlassHandle callee, Symbol* name_sym, Symbol* signature, TRAPS) { Handle empty; Handle name = java_lang_String::create_from_symbol(name_sym, CHECK_(empty)); Handle type; if (signature->utf8_length() > 0 && signature->byte_at(0) == '(') { bool ignore_is_on_bcp = false; type = find_method_handle_type(signature, caller, false, ignore_is_on_bcp, CHECK_(empty)); } else { ResourceMark rm(THREAD); SignatureStream ss(signature, false); if (!ss.is_done()) { oop mirror = ss.as_java_mirror(caller->class_loader(), caller->protection_domain(), SignatureStream::NCDFError, CHECK_(empty)); type = Handle(THREAD, mirror); ss.next(); if (!ss.is_done()) type = Handle(); // error! } } if (type.is_null()) { THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad signature", empty); } // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle JavaCallArguments args; args.push_oop(caller->java_mirror()); // the referring class args.push_int(ref_kind); args.push_oop(callee->java_mirror()); // the target class args.push_oop(name()); 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 code to find or construct a java.lang.invoke.CallSite for the given // name and signature, as interpreted relative to the given class loader. Handle SystemDictionary::make_dynamic_call_site(Handle bootstrap_method, Symbol* name, methodHandle signature_invoker, Handle info, methodHandle caller_method, int caller_bci, TRAPS) { Handle empty; guarantee(bootstrap_method.not_null() && java_lang_invoke_MethodHandle::is_instance(bootstrap_method()), "caller must supply a valid BSM"); Handle caller_mname = MethodHandles::new_MemberName(CHECK_(empty)); MethodHandles::init_MemberName(caller_mname(), caller_method()); // call java.lang.invoke.MethodHandleNatives::makeDynamicCallSite(bootm, name, mtype, info, caller_mname, caller_pos) oop name_str_oop = StringTable::intern(name, CHECK_(empty)); // not a handle! JavaCallArguments args(Handle(THREAD, bootstrap_method())); args.push_oop(name_str_oop); args.push_oop(signature_invoker->method_handle_type()); args.push_oop(info()); args.push_oop(caller_mname()); args.push_int(caller_bci); JavaValue result(T_OBJECT); JavaCalls::call_static(&result, SystemDictionary::MethodHandleNatives_klass(), vmSymbols::makeDynamicCallSite_name(), vmSymbols::makeDynamicCallSite_signature(), &args, CHECK_(empty)); oop call_site_oop = (oop) result.get_jobject(); assert(call_site_oop->is_oop() /*&& java_lang_invoke_CallSite::is_instance(call_site_oop)*/, "must be sane"); if (TraceMethodHandles) { #ifndef PRODUCT tty->print_cr("Linked invokedynamic bci=%d site="INTPTR_FORMAT":", caller_bci, call_site_oop); call_site_oop->print(); tty->cr(); #endif //PRODUCT } return call_site_oop; } Handle SystemDictionary::find_bootstrap_method(methodHandle caller_method, int caller_bci, int cache_index, Handle& argument_info_result, TRAPS) { Handle empty; constantPoolHandle pool; { klassOop caller = caller_method->method_holder(); if (!Klass::cast(caller)->oop_is_instance()) return empty; pool = constantPoolHandle(THREAD, instanceKlass::cast(caller)->constants()); } int constant_pool_index = pool->cache()->entry_at(cache_index)->constant_pool_index(); constantTag tag = pool->tag_at(constant_pool_index); if (tag.is_invoke_dynamic()) { // JVM_CONSTANT_InvokeDynamic is an ordered pair of [bootm, name&type], plus optional arguments // The bootm, being a JVM_CONSTANT_MethodHandle, has its own cache entry. int bsm_index = pool->invoke_dynamic_bootstrap_method_ref_index_at(constant_pool_index); if (bsm_index != 0) { int bsm_index_in_cache = pool->cache()->entry_at(cache_index)->bootstrap_method_index_in_cache(); DEBUG_ONLY(int bsm_index_2 = pool->cache()->entry_at(bsm_index_in_cache)->constant_pool_index()); assert(bsm_index == bsm_index_2, "BSM constant lifted to cache"); if (TraceMethodHandles) { tty->print_cr("resolving bootstrap method for "PTR_FORMAT" at %d at cache[%d]CP[%d]...", (intptr_t) caller_method(), caller_bci, cache_index, constant_pool_index); } oop bsm_oop = pool->resolve_cached_constant_at(bsm_index_in_cache, CHECK_(empty)); if (TraceMethodHandles) { tty->print_cr("bootstrap method for "PTR_FORMAT" at %d retrieved as "PTR_FORMAT":", (intptr_t) caller_method(), caller_bci, (intptr_t) bsm_oop); } assert(bsm_oop->is_oop(), "must be sane"); // caller must verify that it is of type MethodHandle Handle bsm(THREAD, bsm_oop); bsm_oop = NULL; // safety // Extract the optional static arguments. Handle argument_info; // either null, or one arg, or Object[]{arg...} int argc = pool->invoke_dynamic_argument_count_at(constant_pool_index); if (TraceInvokeDynamic) { tty->print_cr("find_bootstrap_method: [%d/%d] CONSTANT_InvokeDynamic: %d[%d]", constant_pool_index, cache_index, bsm_index, argc); } if (argc > 0) { objArrayHandle arg_array; if (argc > 1) { objArrayOop arg_array_oop = oopFactory::new_objArray(SystemDictionary::Object_klass(), argc, CHECK_(empty)); arg_array = objArrayHandle(THREAD, arg_array_oop); argument_info = arg_array; } for (int arg_i = 0; arg_i < argc; arg_i++) { int arg_index = pool->invoke_dynamic_argument_index_at(constant_pool_index, arg_i); oop arg_oop = pool->resolve_possibly_cached_constant_at(arg_index, CHECK_(empty)); if (arg_array.is_null()) { argument_info = Handle(THREAD, arg_oop); } else { arg_array->obj_at_put(arg_i, arg_oop); } } } argument_info_result = argument_info; // return argument_info to caller return bsm; } } else { ShouldNotReachHere(); // verifier does not allow this } return empty; } // Since the identity hash code for symbols changes when the symbols are // moved from the regular perm gen (hash in the mark word) to the shared // spaces (hash is the address), the classes loaded into the dictionary // may be in the wrong buckets. void SystemDictionary::reorder_dictionary() { dictionary()->reorder_dictionary(); } void SystemDictionary::copy_buckets(char** top, char* end) { dictionary()->copy_buckets(top, end); } void SystemDictionary::copy_table(char** top, char* end) { dictionary()->copy_table(top, end); } void SystemDictionary::reverse() { dictionary()->reverse(); } int SystemDictionary::number_of_classes() { return dictionary()->number_of_entries(); } // ---------------------------------------------------------------------------- #ifndef PRODUCT void SystemDictionary::print() { dictionary()->print(); // Placeholders GCMutexLocker mu(SystemDictionary_lock); placeholders()->print(); // loader constraints - print under SD_lock constraints()->print(); } #endif void SystemDictionary::verify() { guarantee(dictionary() != NULL, "Verify of system dictionary failed"); guarantee(constraints() != NULL, "Verify of loader constraints failed"); guarantee(dictionary()->number_of_entries() >= 0 && placeholders()->number_of_entries() >= 0, "Verify of system dictionary failed"); // Verify dictionary dictionary()->verify(); GCMutexLocker mu(SystemDictionary_lock); placeholders()->verify(); // Verify constraint table guarantee(constraints() != NULL, "Verify of loader constraints failed"); constraints()->verify(dictionary(), placeholders()); } void SystemDictionary::verify_obj_klass_present(Handle obj, Symbol* class_name, Handle class_loader) { GCMutexLocker mu(SystemDictionary_lock); Symbol* name; klassOop probe = find_class(class_name, class_loader); if (probe == NULL) { probe = SystemDictionary::find_shared_class(class_name); if (probe == NULL) { name = find_placeholder(class_name, class_loader); } } guarantee(probe != NULL || name != NULL, "Loaded klasses should be in SystemDictionary"); } #ifndef PRODUCT // statistics code class ClassStatistics: AllStatic { private: static int nclasses; // number of classes static int nmethods; // number of methods static int nmethoddata; // number of methodData static int class_size; // size of class objects in words static int method_size; // size of method objects in words static int debug_size; // size of debug info in methods static int methoddata_size; // size of methodData objects in words static void do_class(klassOop k) { nclasses++; class_size += k->size(); if (k->klass_part()->oop_is_instance()) { instanceKlass* ik = (instanceKlass*)k->klass_part(); class_size += ik->methods()->size(); class_size += ik->constants()->size(); class_size += ik->local_interfaces()->size(); class_size += ik->transitive_interfaces()->size(); // We do not have to count implementors, since we only store one! class_size += ik->fields()->size(); } } static void do_method(methodOop m) { nmethods++; method_size += m->size(); // class loader uses same objArray for empty vectors, so don't count these if (m->exception_table()->length() != 0) method_size += m->exception_table()->size(); if (m->has_stackmap_table()) { method_size += m->stackmap_data()->size(); } methodDataOop mdo = m->method_data(); if (mdo != NULL) { nmethoddata++; methoddata_size += mdo->size(); } } public: static void print() { SystemDictionary::classes_do(do_class); SystemDictionary::methods_do(do_method); tty->print_cr("Class statistics:"); tty->print_cr("%d classes (%d bytes)", nclasses, class_size * oopSize); tty->print_cr("%d methods (%d bytes = %d base + %d debug info)", nmethods, (method_size + debug_size) * oopSize, method_size * oopSize, debug_size * oopSize); tty->print_cr("%d methoddata (%d bytes)", nmethoddata, methoddata_size * oopSize); } }; int ClassStatistics::nclasses = 0; int ClassStatistics::nmethods = 0; int ClassStatistics::nmethoddata = 0; int ClassStatistics::class_size = 0; int ClassStatistics::method_size = 0; int ClassStatistics::debug_size = 0; int ClassStatistics::methoddata_size = 0; void SystemDictionary::print_class_statistics() { ResourceMark rm; ClassStatistics::print(); } class MethodStatistics: AllStatic { public: enum { max_parameter_size = 10 }; private: static int _number_of_methods; static int _number_of_final_methods; static int _number_of_static_methods; static int _number_of_native_methods; static int _number_of_synchronized_methods; static int _number_of_profiled_methods; static int _number_of_bytecodes; static int _parameter_size_profile[max_parameter_size]; static int _bytecodes_profile[Bytecodes::number_of_java_codes]; static void initialize() { _number_of_methods = 0; _number_of_final_methods = 0; _number_of_static_methods = 0; _number_of_native_methods = 0; _number_of_synchronized_methods = 0; _number_of_profiled_methods = 0; _number_of_bytecodes = 0; for (int i = 0; i < max_parameter_size ; i++) _parameter_size_profile[i] = 0; for (int j = 0; j < Bytecodes::number_of_java_codes; j++) _bytecodes_profile [j] = 0; }; static void do_method(methodOop m) { _number_of_methods++; // collect flag info if (m->is_final() ) _number_of_final_methods++; if (m->is_static() ) _number_of_static_methods++; if (m->is_native() ) _number_of_native_methods++; if (m->is_synchronized()) _number_of_synchronized_methods++; if (m->method_data() != NULL) _number_of_profiled_methods++; // collect parameter size info (add one for receiver, if any) _parameter_size_profile[MIN2(m->size_of_parameters() + (m->is_static() ? 0 : 1), max_parameter_size - 1)]++; // collect bytecodes info { Thread *thread = Thread::current(); HandleMark hm(thread); BytecodeStream s(methodHandle(thread, m)); Bytecodes::Code c; while ((c = s.next()) >= 0) { _number_of_bytecodes++; _bytecodes_profile[c]++; } } } public: static void print() { initialize(); SystemDictionary::methods_do(do_method); // generate output tty->cr(); tty->print_cr("Method statistics (static):"); // flag distribution tty->cr(); tty->print_cr("%6d final methods %6.1f%%", _number_of_final_methods , _number_of_final_methods * 100.0F / _number_of_methods); tty->print_cr("%6d static methods %6.1f%%", _number_of_static_methods , _number_of_static_methods * 100.0F / _number_of_methods); tty->print_cr("%6d native methods %6.1f%%", _number_of_native_methods , _number_of_native_methods * 100.0F / _number_of_methods); tty->print_cr("%6d synchronized methods %6.1f%%", _number_of_synchronized_methods, _number_of_synchronized_methods * 100.0F / _number_of_methods); tty->print_cr("%6d profiled methods %6.1f%%", _number_of_profiled_methods, _number_of_profiled_methods * 100.0F / _number_of_methods); // parameter size profile tty->cr(); { int tot = 0; int avg = 0; for (int i = 0; i < max_parameter_size; i++) { int n = _parameter_size_profile[i]; tot += n; avg += n*i; tty->print_cr("parameter size = %1d: %6d methods %5.1f%%", i, n, n * 100.0F / _number_of_methods); } assert(tot == _number_of_methods, "should be the same"); tty->print_cr(" %6d methods 100.0%%", _number_of_methods); tty->print_cr("(average parameter size = %3.1f including receiver, if any)", (float)avg / _number_of_methods); } // bytecodes profile tty->cr(); { int tot = 0; for (int i = 0; i < Bytecodes::number_of_java_codes; i++) { if (Bytecodes::is_defined(i)) { Bytecodes::Code c = Bytecodes::cast(i); int n = _bytecodes_profile[c]; tot += n; tty->print_cr("%9d %7.3f%% %s", n, n * 100.0F / _number_of_bytecodes, Bytecodes::name(c)); } } assert(tot == _number_of_bytecodes, "should be the same"); tty->print_cr("%9d 100.000%%", _number_of_bytecodes); } tty->cr(); } }; int MethodStatistics::_number_of_methods; int MethodStatistics::_number_of_final_methods; int MethodStatistics::_number_of_static_methods; int MethodStatistics::_number_of_native_methods; int MethodStatistics::_number_of_synchronized_methods; int MethodStatistics::_number_of_profiled_methods; int MethodStatistics::_number_of_bytecodes; int MethodStatistics::_parameter_size_profile[MethodStatistics::max_parameter_size]; int MethodStatistics::_bytecodes_profile[Bytecodes::number_of_java_codes]; void SystemDictionary::print_method_statistics() { MethodStatistics::print(); } #endif // PRODUCT