jdk-sandbox: comparison src/hotspot/share/classfile/systemDictionary.cpp

equal deleted inserted replaced

-:4ebc2e2fb97c
+:71c04702a3d5
+/*
+* Copyright (c) 1997, 2017, 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 "aot/aotLoader.hpp"
+#include "classfile/classFileParser.hpp"
+#include "classfile/classFileStream.hpp"
+#include "classfile/classLoader.hpp"
+#include "classfile/classLoaderData.inline.hpp"
+#include "classfile/classLoaderExt.hpp"
+#include "classfile/dictionary.hpp"
+#include "classfile/javaClasses.inline.hpp"
+#include "classfile/klassFactory.hpp"
+#include "classfile/loaderConstraints.hpp"
+#include "classfile/packageEntry.hpp"
+#include "classfile/placeholders.hpp"
+#include "classfile/protectionDomainCache.hpp"
+#include "classfile/resolutionErrors.hpp"
+#include "classfile/stringTable.hpp"
+#include "classfile/systemDictionary.hpp"
+#include "classfile/vmSymbols.hpp"
+#include "code/codeCache.hpp"
+#include "compiler/compileBroker.hpp"
+#include "gc/shared/gcLocker.hpp"
+#include "gc/shared/gcTraceTime.inline.hpp"
+#include "interpreter/bytecodeStream.hpp"
+#include "interpreter/interpreter.hpp"
+#include "logging/log.hpp"
+#include "logging/logStream.hpp"
+#include "memory/filemap.hpp"
+#include "memory/metaspaceClosure.hpp"
+#include "memory/oopFactory.hpp"
+#include "memory/resourceArea.hpp"
+#include "oops/instanceKlass.hpp"
+#include "oops/instanceRefKlass.hpp"
+#include "oops/klass.inline.hpp"
+#include "oops/methodData.hpp"
+#include "oops/objArrayKlass.hpp"
+#include "oops/objArrayOop.inline.hpp"
+#include "oops/oop.inline.hpp"
+#include "oops/symbol.hpp"
+#include "oops/typeArrayKlass.hpp"
+#include "prims/jvm.h"
+#include "prims/jvmtiEnvBase.hpp"
+#include "prims/resolvedMethodTable.hpp"
+#include "prims/methodHandles.hpp"
+#include "runtime/arguments.hpp"
+#include "runtime/arguments_ext.hpp"
+#include "runtime/biasedLocking.hpp"
+#include "runtime/fieldType.hpp"
+#include "runtime/handles.inline.hpp"
+#include "runtime/java.hpp"
+#include "runtime/javaCalls.hpp"
+#include "runtime/mutexLocker.hpp"
+#include "runtime/orderAccess.inline.hpp"
+#include "runtime/signature.hpp"
+#include "services/classLoadingService.hpp"
+#include "services/diagnosticCommand.hpp"
+#include "services/threadService.hpp"
+#include "trace/tracing.hpp"
+#include "utilities/macros.hpp"
+#if INCLUDE_CDS
+#include "classfile/sharedClassUtil.hpp"
+#include "classfile/systemDictionaryShared.hpp"
+#endif
+#if INCLUDE_JVMCI
+#include "jvmci/jvmciRuntime.hpp"
+#endif
+PlaceholderTable*      SystemDictionary::_placeholders        = NULL;
+Dictionary*            SystemDictionary::_shared_dictionary   = NULL;
+LoaderConstraintTable* SystemDictionary::_loader_constraints  = NULL;
+ResolutionErrorTable*  SystemDictionary::_resolution_errors   = NULL;
+SymbolPropertyTable*   SystemDictionary::_invoke_method_table = NULL;
+ProtectionDomainCacheTable*   SystemDictionary::_pd_cache_table = NULL;
+int         SystemDictionary::_number_of_modifications = 0;
+oop         SystemDictionary::_system_loader_lock_obj     =  NULL;
+InstanceKlass*      SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
+=  { NULL /*, NULL...*/ };
+InstanceKlass*      SystemDictionary::_box_klasses[T_VOID+1]      =  { NULL /*, NULL...*/ };
+oop         SystemDictionary::_java_system_loader         =  NULL;
+bool        SystemDictionary::_has_loadClassInternal      =  false;
+bool        SystemDictionary::_has_checkPackageAccess     =  false;
+// lazily initialized klass variables
+InstanceKlass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
+// Default ProtectionDomainCacheSize value
+const int defaultProtectionDomainCacheSize = 1009;
+// ----------------------------------------------------------------------------
+// Java-level SystemLoader
+oop SystemDictionary::java_system_loader() {
+return _java_system_loader;
+}
+void SystemDictionary::compute_java_system_loader(TRAPS) {
+Klass* system_klass = WK_KLASS(ClassLoader_klass);
+JavaValue result(T_OBJECT);
+JavaCalls::call_static(&result,
+WK_KLASS(ClassLoader_klass),
+vmSymbols::getSystemClassLoader_name(),
+vmSymbols::void_classloader_signature(),
+CHECK);
+_java_system_loader = (oop)result.get_jobject();
+CDS_ONLY(SystemDictionaryShared::initialize(CHECK);)
+}
+ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, TRAPS) {
+if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
+return ClassLoaderDataGraph::find_or_create(class_loader, THREAD);
+}
+// ----------------------------------------------------------------------------
+// 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_ClassLoader::parallelCapable(class_loader());
+}
+// ----------------------------------------------------------------------------
+// ParallelDefineClass flag does not apply to bootclass loader
+bool SystemDictionary::is_parallelDefine(Handle class_loader) {
+if (class_loader.is_null()) return false;
+if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
+return true;
+}
+return false;
+}
+// Returns true if the passed class loader is the builtin application class loader
+// or a custom system class loader. A customer system class loader can be
+// specified via -Djava.system.class.loader.
+bool SystemDictionary::is_system_class_loader(oop class_loader) {
+if (class_loader == NULL) {
+return false;
+}
+return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() ||
+class_loader == _java_system_loader);
+}
+// Returns true if the passed class loader is the platform class loader.
+bool SystemDictionary::is_platform_class_loader(oop class_loader) {
+if (class_loader == NULL) {
+return false;
+}
+return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass());
+}
+// ----------------------------------------------------------------------------
+// Resolving of classes
+// Forwards to resolve_or_null
+Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
+Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
+if (HAS_PENDING_EXCEPTION || klass == NULL) {
+// can return a null klass
+klass = handle_resolution_exception(class_name, throw_error, klass, THREAD);
+}
+return klass;
+}
+Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name,
+bool throw_error,
+Klass* klass, TRAPS) {
+if (HAS_PENDING_EXCEPTION) {
+// If we have a pending exception we forward it to the caller, unless throw_error is true,
+// in which case we have to check whether the pending exception is a ClassNotFoundException,
+// and if so convert it to a NoClassDefFoundError
+// And chain the original ClassNotFoundException
+if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
+ResourceMark rm(THREAD);
+assert(klass == NULL, "Should not have result with exception pending");
+Handle e(THREAD, PENDING_EXCEPTION);
+CLEAR_PENDING_EXCEPTION;
+THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
+} else {
+return NULL;
+}
+}
+// Class not found, throw appropriate error or exception depending on value of throw_error
+if (klass == NULL) {
+ResourceMark rm(THREAD);
+if (throw_error) {
+THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
+} else {
+THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
+}
+}
+return klass;
+}
+Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
+bool throw_error, TRAPS)
+{
+return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
+}
+// Forwards to resolve_instance_class_or_null
+Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
+assert(THREAD->can_call_java(),
+"can not load classes with compiler thread: class=%s, classloader=%s",
+class_name->as_C_string(),
+class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string());
+if (FieldType::is_array(class_name)) {
+return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD);
+} else if (FieldType::is_obj(class_name)) {
+ResourceMark rm(THREAD);
+// Ignore wrapping L and ;.
+TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
+class_name->utf8_length() - 2, CHECK_NULL);
+return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD);
+} else {
+return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD);
+}
+}
+Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
+return resolve_or_null(class_name, Handle(), Handle(), THREAD);
+}
+// Forwards to resolve_instance_class_or_null
+Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
+Handle class_loader,
+Handle protection_domain,
+TRAPS) {
+assert(FieldType::is_array(class_name), "must be array");
+Klass* k = NULL;
+FieldArrayInfo fd;
+// dimension and object_key in FieldArrayInfo are assigned as a side-effect
+// of this call
+BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
+if (t == T_OBJECT) {
+// naked oop "k" is OK here -- we assign back into it
+k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
+class_loader,
+protection_domain,
+CHECK_NULL);
+if (k != NULL) {
+k = k->array_klass(fd.dimension(), CHECK_NULL);
+}
+} else {
+k = Universe::typeArrayKlassObj(t);
+k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
+}
+return k;
+}
+// Must be called for any super-class or super-interface resolution
+// during class definition to allow class circularity checking
+// super-interface callers:
+//    parse_interfaces - for defineClass & jvmtiRedefineClasses
+// super-class callers:
+//   ClassFileParser - for defineClass & jvmtiRedefineClasses
+//   load_shared_class - while loading a class from shared archive
+//   resolve_instance_class_or_null:
+//     via: handle_parallel_super_load
+//      when resolving a class that has an existing placeholder with
+//      a saved superclass [i.e. a defineClass is currently in progress]
+//      if another thread is trying to resolve the class, it must do
+//      super-class checks on its own thread to catch class circularity
+// This last call is critical in class circularity checking for cases
+// where classloading is delegated to different threads and the
+// classloader lock is released.
+// Take the case: Base->Super->Base
+//   1. If thread T1 tries to do a defineClass of class Base
+//    resolve_super_or_fail creates placeholder: T1, Base (super Super)
+//   2. resolve_instance_class_or_null does not find SD or placeholder for Super
+//    so it tries to load Super
+//   3. If we load the class internally, or user classloader uses same thread
+//      loadClassFromxxx or defineClass via parseClassFile Super ...
+//      3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
+//      3.3 resolve_instance_class_or_null Base, finds placeholder for Base
+//      3.4 calls resolve_super_or_fail Base
+//      3.5 finds T1,Base -> throws class circularity
+//OR 4. If T2 tries to resolve Super via defineClass Super ...
+//      4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
+//      4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
+//      4.3 calls resolve_super_or_fail Super in parallel on own thread T2
+//      4.4 finds T2, Super -> throws class circularity
+// Must be called, even if superclass is null, since this is
+// where the placeholder entry is created which claims this
+// thread is loading this class/classloader.
+// Be careful when modifying this code: once you have run
+// placeholders()->find_and_add(PlaceholderTable::LOAD_SUPER),
+// you need to find_and_remove it before returning.
+// So be careful to not exit with a CHECK_ macro betweeen these calls.
+Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
+Symbol* class_name,
+Handle class_loader,
+Handle protection_domain,
+bool is_superclass,
+TRAPS) {
+#if INCLUDE_CDS
+if (DumpSharedSpaces) {
+// Special processing for CDS dump time.
+Klass* k = SystemDictionaryShared::dump_time_resolve_super_or_fail(child_name,
+class_name, class_loader, protection_domain, is_superclass, CHECK_NULL);
+if (k) {
+return k;
+}
+}
+#endif // INCLUDE_CDS
+// Double-check, if child class is already loaded, just return super-class,interface
+// Don't add a placedholder if already loaded, i.e. already in appropriate class loader
+// dictionary.
+// Make sure there's a placeholder for the *child* before resolving.
+// Used as a claim that this thread is currently loading superclass/classloader
+// Used here for ClassCircularity checks and also for heap verification
+// (every InstanceKlass needs to be in its class loader dictionary or have a placeholder).
+// Must check ClassCircularity before checking if super class is already loaded.
+//
+// We might not already have a placeholder if this child_name was
+// first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
+// the name of the class might not be known until the stream is actually
+// parsed.
+// Bugs 4643874, 4715493
+ClassLoaderData* loader_data = class_loader_data(class_loader);
+Dictionary* dictionary = loader_data->dictionary();
+unsigned int d_hash = dictionary->compute_hash(child_name);
+int d_index = dictionary->hash_to_index(d_hash);
+unsigned int p_hash = placeholders()->compute_hash(child_name);
+int p_index = placeholders()->hash_to_index(p_hash);
+// can't throw error holding a lock
+bool child_already_loaded = false;
+bool throw_circularity_error = false;
+{
+MutexLocker mu(SystemDictionary_lock, THREAD);
+Klass* childk = find_class(d_index, d_hash, child_name, dictionary);
+Klass* quicksuperk;
+// to support // loading: if child done loading, just return superclass
+// if class_name, & class_loader don't match:
+// if initial define, SD update will give LinkageError
+// if redefine: compare_class_versions will give HIERARCHY_CHANGED
+// so we don't throw an exception here.
+// see: nsk redefclass014 & java.lang.instrument Instrument032
+if ((childk != NULL ) && (is_superclass) &&
+((quicksuperk = childk->super()) != NULL) &&
+((quicksuperk->name() == class_name) &&
+(quicksuperk->class_loader()  == class_loader()))) {
+return quicksuperk;
+} else {
+PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
+if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
+throw_circularity_error = true;
+}
+}
+if (!throw_circularity_error) {
+// Be careful not to exit resolve_super
+PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
+}
+}
+if (throw_circularity_error) {
+ResourceMark rm(THREAD);
+THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
+}
+// java.lang.Object should have been found above
+assert(class_name != NULL, "null super class for resolving");
+// Resolve the super class or interface, check results on return
+Klass* superk = SystemDictionary::resolve_or_null(class_name,
+class_loader,
+protection_domain,
+THREAD);
+// Clean up of placeholders moved so that each classloadAction registrar self-cleans up
+// It is no longer necessary to keep the placeholder table alive until update_dictionary
+// or error. GC used to walk the placeholder table as strong roots.
+// The instanceKlass is kept alive because the class loader is on the stack,
+// which keeps the loader_data alive, as well as all instanceKlasses in
+// the loader_data. parseClassFile adds the instanceKlass to loader_data.
+{
+MutexLocker mu(SystemDictionary_lock, THREAD);
+placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
+SystemDictionary_lock->notify_all();
+}
+if (HAS_PENDING_EXCEPTION || superk == NULL) {
+// can null superk
+superk = handle_resolution_exception(class_name, true, superk, THREAD);
+}
+return superk;
+}
+void SystemDictionary::validate_protection_domain(InstanceKlass* klass,
+Handle class_loader,
+Handle protection_domain,
+TRAPS) {
+if(!has_checkPackageAccess()) return;
+// Now we have to call back to java to check if the initating class has access
+JavaValue result(T_VOID);
+LogTarget(Debug, protectiondomain) lt;
+if (lt.is_enabled()) {
+ResourceMark rm;
+// Print out trace information
+LogStream ls(lt);
+ls.print_cr("Checking package access");
+ls.print("class loader: "); class_loader()->print_value_on(&ls);
+ls.print(" protection domain: "); protection_domain()->print_value_on(&ls);
+ls.print(" loading: "); klass->print_value_on(&ls);
+ls.cr();
+}
+// This handle and the class_loader handle passed in keeps this class from
+// being unloaded through several GC points.
+// The class_loader handle passed in is the initiating loader.
+Handle mirror(THREAD, klass->java_mirror());
+InstanceKlass* system_loader = SystemDictionary::ClassLoader_klass();
+JavaCalls::call_special(&result,
+class_loader,
+system_loader,
+vmSymbols::checkPackageAccess_name(),
+vmSymbols::class_protectiondomain_signature(),
+mirror,
+protection_domain,
+THREAD);
+if (HAS_PENDING_EXCEPTION) {
+log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!");
+} else {
+log_debug(protectiondomain)("granted");
+}
+if (HAS_PENDING_EXCEPTION) return;
+// If no exception has been thrown, we have validated the protection domain
+// Insert the protection domain of the initiating class into the set.
+{
+ClassLoaderData* loader_data = class_loader_data(class_loader);
+Dictionary* dictionary = loader_data->dictionary();
+Symbol*  kn = klass->name();
+unsigned int d_hash = dictionary->compute_hash(kn);
+int d_index = dictionary->hash_to_index(d_hash);
+MutexLocker mu(SystemDictionary_lock, THREAD);
+dictionary->add_protection_domain(d_index, d_hash, klass,
+protection_domain, THREAD);
+}
+}
+// We only get here if this thread finds that another thread
+// has already claimed the placeholder token for the current operation,
+// but that other thread either never owned or gave up the
+// object lock
+// Waits on SystemDictionary_lock to indicate placeholder table updated
+// On return, caller must recheck placeholder table state
+//
+// We only get here if
+//  1) custom classLoader, i.e. not bootstrap classloader
+//  2) 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: must call resolve_super_or_fail even if null super -
+// to force placeholder entry creation for this class for circularity detection
+// Caller must check for pending exception
+// Returns non-null Klass* if other thread has completed load
+// and we are done,
+// If return null Klass* and no pending exception, the caller must load the class
+InstanceKlass* SystemDictionary::handle_parallel_super_load(
+Symbol* name, Symbol* superclassname, Handle class_loader,
+Handle protection_domain, Handle lockObject, TRAPS) {
+ClassLoaderData* loader_data = class_loader_data(class_loader);
+Dictionary* dictionary = loader_data->dictionary();
+unsigned int d_hash = dictionary->compute_hash(name);
+int d_index = dictionary->hash_to_index(d_hash);
+unsigned int p_hash = placeholders()->compute_hash(name);
+int p_index = placeholders()->hash_to_index(p_hash);
+// superk is not used, resolve_super called for circularity check only
+// This code is reached in two situations. One if this thread
+// is loading the same class twice (e.g. ClassCircularity, or
+// java.lang.instrument).
+// The second is if another thread started the resolve_super first
+// and has not yet finished.
+// In both cases the original caller will clean up the placeholder
+// entry on error.
+Klass* superk = SystemDictionary::resolve_super_or_fail(name,
+superclassname,
+class_loader,
+protection_domain,
+true,
+CHECK_NULL);
+// parallelCapable class loaders do NOT wait for parallel superclass loads to complete
+// Serial class loaders and bootstrap classloader do wait for superclass loads
+if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
+MutexLocker mu(SystemDictionary_lock, THREAD);
+// Check if classloading completed while we were loading superclass or waiting
+return find_class(d_index, d_hash, name, dictionary);
+}
+// must loop to both handle other placeholder updates
+// and spurious notifications
+bool super_load_in_progress = true;
+PlaceholderEntry* placeholder;
+while (super_load_in_progress) {
+MutexLocker mu(SystemDictionary_lock, THREAD);
+// Check if classloading completed while we were loading superclass or waiting
+InstanceKlass* check = find_class(d_index, d_hash, name, dictionary);
+if (check != NULL) {
+// Klass is already loaded, so just return it
+return check;
+} else {
+placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
+if (placeholder && placeholder->super_load_in_progress() ){
+// 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 NULL;
+}
+static void post_class_load_event(EventClassLoad* event,
+const InstanceKlass* k,
+const ClassLoaderData* init_cld) {
+#if INCLUDE_TRACE
+assert(event != NULL, "invariant");
+assert(k != NULL, "invariant");
+if (event->should_commit()) {
+event->set_loadedClass(k);
+event->set_definingClassLoader(k->class_loader_data());
+event->set_initiatingClassLoader(init_cld);
+event->commit();
+}
+#endif // INCLUDE_TRACE
+}
+static void class_define_event(InstanceKlass* k,
+const ClassLoaderData* def_cld) {
+#if INCLUDE_TRACE
+EventClassDefine event;
+if (event.should_commit()) {
+event.set_definedClass(k);
+event.set_definingClassLoader(def_cld);
+event.commit();
+}
+#endif // INCLUDE_TRACE
+}
+// Be careful when modifying this code: once you have run
+// placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE),
+// you need to find_and_remove it before returning.
+// So be careful to not exit with a CHECK_ macro betweeen these calls.
+Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
+Handle class_loader,
+Handle protection_domain,
+TRAPS) {
+assert(name != NULL && !FieldType::is_array(name) &&
+!FieldType::is_obj(name), "invalid class name");
+EventClassLoad class_load_start_event;
+HandleMark hm(THREAD);
+// Fix for 4474172; see evaluation for more details
+class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
+ClassLoaderData *loader_data = register_loader(class_loader, CHECK_NULL);
+Dictionary* dictionary = loader_data->dictionary();
+// Do lookup to see if class already exist and the protection domain
+// has the right access
+// This call uses find which checks protection domain already matches
+// All subsequent calls use find_class, and set has_loaded_class so that
+// before we return a result we call out to java to check for valid protection domain
+// to allow returning the Klass* and add it to the pd_set if it is valid
+unsigned int d_hash = dictionary->compute_hash(name);
+int d_index = dictionary->hash_to_index(d_hash);
+Klass* probe = dictionary->find(d_index, d_hash, name, protection_domain);
+if (probe != NULL) return probe;
+// Non-bootstrap class loaders will call out to class loader and
+// define via jvm/jni_DefineClass which will acquire the
+// class loader object lock to protect against multiple threads
+// defining the class in parallel by accident.
+// This lock must be acquired here so the waiter will find
+// any successful result in the SystemDictionary and not attempt
+// the define
+// ParallelCapable Classloaders and the bootstrap classloader,
+// 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);
+int p_index = placeholders()->hash_to_index(p_hash);
+// Class is not in SystemDictionary so we have to do loading.
+// Make sure we are synchronized on the class loader before we proceed
+Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
+check_loader_lock_contention(lockObject, THREAD);
+ObjectLocker ol(lockObject, THREAD, DoObjectLock);
+// Check again (after locking) if class already exist in SystemDictionary
+bool class_has_been_loaded   = false;
+bool super_load_in_progress  = false;
+bool havesupername = false;
+InstanceKlass* k = NULL;
+PlaceholderEntry* placeholder;
+Symbol* superclassname = NULL;
+{
+MutexLocker mu(SystemDictionary_lock, THREAD);
+InstanceKlass* check = find_class(d_index, d_hash, name, dictionary);
+if (check != NULL) {
+// Klass is already loaded, so just return it
+class_has_been_loaded = true;
+k = check;
+} else {
+placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
+if (placeholder && placeholder->super_load_in_progress()) {
+super_load_in_progress = true;
+if (placeholder->havesupername() == true) {
+superclassname = placeholder->supername();
+havesupername = true;
+}
+}
+}
+}
+// If the class is in the placeholder table, class loading is in progress
+if (super_load_in_progress && havesupername==true) {
+k = handle_parallel_super_load(name,
+superclassname,
+class_loader,
+protection_domain,
+lockObject, THREAD);
+if (HAS_PENDING_EXCEPTION) {
+return NULL;
+}
+if (k != NULL) {
+class_has_been_loaded = true;
+}
+}
+bool throw_circularity_error = false;
+if (!class_has_been_loaded) {
+bool load_instance_added = false;
+// add placeholder entry to record loading instance class
+// Five cases:
+// All cases need to prevent modifying bootclasssearchpath
+// in parallel with a classload of same classname
+// Redefineclasses uses existence of the placeholder for the duration
+// of the class load to prevent concurrent redefinition of not completely
+// defined classes.
+// case 1. traditional classloaders that rely on the classloader object lock
+//   - no other need for LOAD_INSTANCE
+// case 2. traditional classloaders that break the classloader object lock
+//    as a deadlock workaround. Detection of this case requires that
+//    this check is done while holding the classloader object lock,
+//    and that lock is still held when calling classloader's loadClass.
+//    For these classloaders, we ensure that the first requestor
+//    completes the load and other requestors wait for completion.
+// case 3. 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
+{
+MutexLocker mu(SystemDictionary_lock, THREAD);
+if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
+PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
+if (oldprobe) {
+// only need check_seen_thread once, not on each loop
+// 6341374 java/lang/Instrument with -Xcomp
+if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
+throw_circularity_error = true;
+} else {
+// case 1: traditional: should never see load_in_progress.
+while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
+// case 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
+InstanceKlass* check = find_class(d_index, d_hash, name, dictionary);
+if (check != NULL) {
+// Klass is already loaded, so just return it
+k = check;
+class_has_been_loaded = true;
+}
+// check if other thread failed to load and cleaned up
+oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
+}
+}
+}
+}
+// All cases: add LOAD_INSTANCE holding SystemDictionary_lock
+// case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try
+// LOAD_INSTANCE in parallel
+if (!throw_circularity_error && !class_has_been_loaded) {
+PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
+load_instance_added = true;
+// For class loaders that do not acquire the classloader object lock,
+// if they did not catch another thread holding LOAD_INSTANCE,
+// need a check analogous to the acquire ObjectLocker/find_class
+// i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
+// one final check if the load has already completed
+// class loaders holding the ObjectLock shouldn't find the class here
+InstanceKlass* check = find_class(d_index, d_hash, name, dictionary);
+if (check != NULL) {
+// Klass is already loaded, so return it after checking/adding protection domain
+k = check;
+class_has_been_loaded = true;
+}
+}
+}
+// must throw error outside of owning lock
+if (throw_circularity_error) {
+assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
+ResourceMark rm(THREAD);
+THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
+}
+if (!class_has_been_loaded) {
+// Do actual loading
+k = load_instance_class(name, class_loader, THREAD);
+// 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 == NULL && HAS_PENDING_EXCEPTION
+&& PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass())) {
+MutexLocker mu(SystemDictionary_lock, THREAD);
+InstanceKlass* check = find_class(d_index, d_hash, name, dictionary);
+if (check != NULL) {
+// Klass is already loaded, so just use it
+k = check;
+CLEAR_PENDING_EXCEPTION;
+guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?");
+}
+}
+}
+// If everything was OK (no exceptions, no null return value), and
+// class_loader is NOT the defining loader, do a little more bookkeeping.
+if (!HAS_PENDING_EXCEPTION && k != NULL &&
+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);
+}
+}
+}
+} // load_instance_class
+if (load_instance_added == true) {
+// clean up placeholder entries for LOAD_INSTANCE success or error
+// This brackets the SystemDictionary updates for both defining
+// and initiating loaders
+MutexLocker mu(SystemDictionary_lock, THREAD);
+placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
+SystemDictionary_lock->notify_all();
+}
+}
+if (HAS_PENDING_EXCEPTION || k == NULL) {
+return NULL;
+}
+post_class_load_event(&class_load_start_event, k, loader_data);
+#ifdef ASSERT
+{
+ClassLoaderData* loader_data = k->class_loader_data();
+MutexLocker mu(SystemDictionary_lock, THREAD);
+Klass* kk = find_class(name, loader_data);
+assert(kk == k, "should be present in dictionary");
+}
+#endif
+// return if the protection domain in NULL
+if (protection_domain() == NULL) return k;
+// Check the protection domain has the right access
+if (dictionary->is_valid_protection_domain(d_index, d_hash, name,
+protection_domain)) {
+return k;
+}
+// Verify protection domain. If it fails an exception is thrown
+validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
+return k;
+}
+// This routine does not lock the system dictionary.
+//
+// Since readers don't hold a lock, we must make sure that system
+// dictionary entries are only removed at a safepoint (when only one
+// thread is running), and are added to in a safe way (all links must
+// be updated in an MT-safe manner).
+//
+// Callers should be aware that an entry could be added just after
+// _dictionary->bucket(index) is read here, so the caller will not see
+// the new entry.
+Klass* SystemDictionary::find(Symbol* class_name,
+Handle class_loader,
+Handle protection_domain,
+TRAPS) {
+// The result of this call should be consistent with the result
+// of the call to resolve_instance_class_or_null().
+// See evaluation 6790209 and 4474172 for more details.
+class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
+ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
+if (loader_data == NULL) {
+// If the ClassLoaderData has not been setup,
+// then the class loader has no entries in the dictionary.
+return NULL;
+}
+Dictionary* dictionary = loader_data->dictionary();
+unsigned int d_hash = dictionary->compute_hash(class_name);
+int d_index = dictionary->hash_to_index(d_hash);
+return dictionary->find(d_index, d_hash, class_name,
+protection_domain);
+}
+// Look for a loaded instance or array klass by name.  Do not do any loading.
+// return NULL in case of error.
+Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
+Handle class_loader,
+Handle protection_domain,
+TRAPS) {
+Klass* k = NULL;
+assert(class_name != NULL, "class name must be non NULL");
+if (FieldType::is_array(class_name)) {
+// The name refers to an array.  Parse the name.
+// dimension and object_key in FieldArrayInfo are assigned as a
+// side-effect of this call
+FieldArrayInfo fd;
+BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
+if (t != T_OBJECT) {
+k = Universe::typeArrayKlassObj(t);
+} else {
+k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
+}
+if (k != NULL) {
+k = k->array_klass_or_null(fd.dimension());
+}
+} else {
+k = find(class_name, class_loader, protection_domain, THREAD);
+}
+return k;
+}
+// Note: this method is much like resolve_from_stream, but
+// does not publish the classes via the SystemDictionary.
+// Handles unsafe_DefineAnonymousClass and redefineclasses
+// RedefinedClasses do not add to the class hierarchy
+InstanceKlass* SystemDictionary::parse_stream(Symbol* class_name,
+Handle class_loader,
+Handle protection_domain,
+ClassFileStream* st,
+const InstanceKlass* host_klass,
+GrowableArray<Handle>* cp_patches,
+TRAPS) {
+EventClassLoad class_load_start_event;
+ClassLoaderData* loader_data;
+if (host_klass != NULL) {
+// Create a new CLD for anonymous class, that uses the same class loader
+// as the host_klass
+guarantee(host_klass->class_loader() == class_loader(), "should be the same");
+loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader(), CHECK_NULL);
+} else {
+loader_data = ClassLoaderData::class_loader_data(class_loader());
+}
+assert(st != NULL, "invariant");
+assert(st->need_verify(), "invariant");
+// Parse stream and create a klass.
+// Note that we do this even though this klass might
+// already be present in the SystemDictionary, otherwise we would not
+// throw potential ClassFormatErrors.
+InstanceKlass* k = KlassFactory::create_from_stream(st,
+class_name,
+loader_data,
+protection_domain,
+host_klass,
+cp_patches,
+CHECK_NULL);
+if (host_klass != NULL && k != NULL) {
+// If it's anonymous, initialize it now, since nobody else will.
+{
+MutexLocker mu_r(Compile_lock, THREAD);
+// Add to class hierarchy, initialize vtables, and do possible
+// deoptimizations.
+add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
+// But, do not add to dictionary.
+// compiled code dependencies need to be validated anyway
+notice_modification();
+}
+// Rewrite and patch constant pool here.
+k->link_class(CHECK_NULL);
+if (cp_patches != NULL) {
+k->constants()->patch_resolved_references(cp_patches);
+}
+k->eager_initialize(CHECK_NULL);
+// notify jvmti
+if (JvmtiExport::should_post_class_load()) {
+assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
+JvmtiExport::post_class_load((JavaThread *) THREAD, k);
+}
+post_class_load_event(&class_load_start_event, k, loader_data);
+}
+assert(host_klass != NULL || NULL == cp_patches,
+"cp_patches only found with host_klass");
+return k;
+}
+// Add a klass to the system from a stream (called by jni_DefineClass and
+// JVM_DefineClass).
+// Note: class_name can be NULL. In that case we do not know the name of
+// the class until we have parsed the stream.
+InstanceKlass* SystemDictionary::resolve_from_stream(Symbol* class_name,
+Handle class_loader,
+Handle protection_domain,
+ClassFileStream* st,
+TRAPS) {
+#if INCLUDE_CDS
+ResourceMark rm(THREAD);
+if (DumpSharedSpaces && !class_loader.is_null() &&
+!ArgumentsExt::using_AppCDS() && strcmp(class_name->as_C_string(), "Unnamed") != 0) {
+// If AppCDS is not enabled, don't define the class at dump time (except for the "Unnamed"
+// class, which is used by MethodHandles).
+THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
+}
+#endif
+HandleMark hm(THREAD);
+// 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;
+}
+ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL);
+// Make sure we are synchronized on the class loader before we proceed
+Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
+check_loader_lock_contention(lockObject, THREAD);
+ObjectLocker ol(lockObject, THREAD, DoObjectLock);
+assert(st != NULL, "invariant");
+// Parse the stream and create a klass.
+// Note that we do this even though this klass might
+// already be present in the SystemDictionary, otherwise we would not
+// throw potential ClassFormatErrors.
+InstanceKlass* k = NULL;
+#if INCLUDE_CDS
+if (!DumpSharedSpaces) {
+k = SystemDictionaryShared::lookup_from_stream(class_name,
+class_loader,
+protection_domain,
+st,
+CHECK_NULL);
+}
+#endif
+if (k == NULL) {
+if (st->buffer() == NULL) {
+return NULL;
+}
+k = KlassFactory::create_from_stream(st,
+class_name,
+loader_data,
+protection_domain,
+NULL, // host_klass
+NULL, // cp_patches
+CHECK_NULL);
+}
+assert(k != NULL, "no klass created");
+Symbol* h_name = k->name();
+assert(class_name == NULL || class_name == h_name, "name mismatch");
+// Add class just loaded
+// If a class loader supports parallel classloading handle parallel define requests
+// find_or_define_instance_class may return a different InstanceKlass
+if (is_parallelCapable(class_loader)) {
+InstanceKlass* defined_k = find_or_define_instance_class(h_name, class_loader, k, THREAD);
+if (!HAS_PENDING_EXCEPTION && defined_k != k) {
+// If a parallel capable class loader already defined this class, register 'k' for cleanup.
+assert(defined_k != NULL, "Should have a klass if there's no exception");
+loader_data->add_to_deallocate_list(k);
+k = defined_k;
+}
+} else {
+define_instance_class(k, THREAD);
+}
+// If defining the class throws an exception register 'k' for cleanup.
+if (HAS_PENDING_EXCEPTION) {
+assert(k != NULL, "Must have an instance klass here!");
+loader_data->add_to_deallocate_list(k);
+return NULL;
+}
+// Make sure we have an entry in the SystemDictionary on success
+debug_only( {
+MutexLocker mu(SystemDictionary_lock, THREAD);
+Klass* check = find_class(h_name, k->class_loader_data());
+assert(check == k, "should be present in the dictionary");
+} );
+return k;
+}
+#if INCLUDE_CDS
+void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
+int number_of_entries) {
+assert(length == _shared_dictionary_size * sizeof(HashtableBucket<mtClass>),
+"bad shared dictionary size.");
+_shared_dictionary = new Dictionary(ClassLoaderData::the_null_class_loader_data(),
+_shared_dictionary_size, t, number_of_entries);
+}
+// If there is a shared dictionary, then find the entry for the
+// given shared system class, if any.
+InstanceKlass* SystemDictionary::find_shared_class(Symbol* class_name) {
+if (shared_dictionary() != NULL) {
+unsigned int d_hash = shared_dictionary()->compute_hash(class_name);
+int d_index = shared_dictionary()->hash_to_index(d_hash);
+return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
+} else {
+return NULL;
+}
+}
+// Load a class from the shared spaces (found through the shared system
+// dictionary).  Force the superclass and all interfaces to be loaded.
+// Update the class definition to include sibling classes and no
+// subclasses (yet).  [Classes in the shared space are not part of the
+// object hierarchy until loaded.]
+InstanceKlass* SystemDictionary::load_shared_class(
+Symbol* class_name, Handle class_loader, TRAPS) {
+InstanceKlass* ik = find_shared_class(class_name);
+// Make sure we only return the boot class for the NULL classloader.
+if (ik != NULL &&
+ik->is_shared_boot_class() && class_loader.is_null()) {
+Handle protection_domain;
+return load_shared_class(ik, class_loader, protection_domain, THREAD);
+}
+return NULL;
+}
+// Check if a shared class can be loaded by the specific classloader:
+//
+// NULL classloader:
+//   - Module class from "modules" jimage. ModuleEntry must be defined in the classloader.
+//   - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must
+//     be defined in an unnamed module.
+bool SystemDictionary::is_shared_class_visible(Symbol* class_name,
+InstanceKlass* ik,
+Handle class_loader, TRAPS) {
+assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(),
+"Cannot use sharing if java.base is patched");
+ResourceMark rm;
+int path_index = ik->shared_classpath_index();
+ClassLoaderData* loader_data = class_loader_data(class_loader);
+if (path_index < 0) {
+// path_index < 0 indicates that the class is intended for a custom loader
+// and should not be loaded by boot/platform/app loaders
+if (loader_data->is_builtin_class_loader_data()) {
+return false;
+} else {
+return true;
+}
+}
+SharedClassPathEntry* ent =
+(SharedClassPathEntry*)FileMapInfo::shared_classpath(path_index);
+if (!Universe::is_module_initialized()) {
+assert(ent != NULL && ent->is_jrt(),
+"Loading non-bootstrap classes before the module system is initialized");
+assert(class_loader.is_null(), "sanity");
+return true;
+}
+// Get the pkg_entry from the classloader
+TempNewSymbol pkg_name = NULL;
+PackageEntry* pkg_entry = NULL;
+ModuleEntry* mod_entry = NULL;
+const char* pkg_string = NULL;
+pkg_name = InstanceKlass::package_from_name(class_name, CHECK_false);
+if (pkg_name != NULL) {
+pkg_string = pkg_name->as_C_string();
+if (loader_data != NULL) {
+pkg_entry = loader_data->packages()->lookup_only(pkg_name);
+}
+if (pkg_entry != NULL) {
+mod_entry = pkg_entry->module();
+}
+}
+// If the archived class is from a module that has been patched at runtime,
+// the class cannot be loaded from the archive.
+if (mod_entry != NULL && mod_entry->is_patched()) {
+return false;
+}
+if (class_loader.is_null()) {
+assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry");
+// The NULL classloader can load archived class originated from the
+// "modules" jimage and the -Xbootclasspath/a. For class from the
+// "modules" jimage, the PackageEntry/ModuleEntry must be defined
+// by the NULL classloader.
+if (mod_entry != NULL) {
+// PackageEntry/ModuleEntry is found in the classloader. Check if the
+// ModuleEntry's location agrees with the archived class' origination.
+if (ent->is_jrt() && mod_entry->location()->starts_with("jrt:")) {
+return true; // Module class from the "module" jimage
+}
+}
+// If the archived class is not from the "module" jimage, the class can be
+// loaded by the NULL classloader if
+//
+// 1. the class is from the unamed package
+// 2. or, the class is not from a module defined in the NULL classloader
+// 3. or, the class is from an unamed module
+if (!ent->is_jrt() && ik->is_shared_boot_class()) {
+// the class is from the -Xbootclasspath/a
+if (pkg_string == NULL ||
+pkg_entry == NULL ||
+pkg_entry->in_unnamed_module()) {
+assert(mod_entry == NULL ||
+mod_entry == loader_data->unnamed_module(),
+"the unnamed module is not defined in the classloader");
+return true;
+}
+}
+return false;
+} else {
+bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader(
+ik, class_loader, pkg_string, pkg_name,
+pkg_entry, mod_entry, CHECK_(false));
+return res;
+}
+}
+InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik,
+Handle class_loader,
+Handle protection_domain, TRAPS) {
+if (ik != NULL) {
+Symbol* class_name = ik->name();
+bool visible = is_shared_class_visible(
+class_name, ik, class_loader, CHECK_NULL);
+if (!visible) {
+return NULL;
+}
+// Resolve the superclass and interfaces. They must be the same
+// as in dump time, because the layout of <ik> depends on
+// the specific layout of ik->super() and ik->local_interfaces().
+//
+// If unexpected superclass or interfaces are found, we cannot
+// load <ik> from the shared archive.
+if (ik->super() != NULL) {
+Symbol*  cn = ik->super()->name();
+Klass *s = resolve_super_or_fail(class_name, cn,
+class_loader, protection_domain, true, CHECK_NULL);
+if (s != ik->super()) {
+// The dynamically resolved super class is not the same as the one we used during dump time,
+// so we cannot use ik.
+return NULL;
+} else {
+assert(s->is_shared(), "must be");
+}
+}
+Array<Klass*>* interfaces = ik->local_interfaces();
+int num_interfaces = interfaces->length();
+for (int index = 0; index < num_interfaces; index++) {
+Klass* k = interfaces->at(index);
+Symbol*  name  = k->name();
+Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_NULL);
+if (k != i) {
+// The dynamically resolved interface class is not the same as the one we used during dump time,
+// so we cannot use ik.
+return NULL;
+} else {
+assert(i->is_shared(), "must be");
+}
+}
+InstanceKlass* new_ik = KlassFactory::check_shared_class_file_load_hook(
+ik, class_name, class_loader, protection_domain, CHECK_NULL);
+if (new_ik != NULL) {
+// The class is changed by CFLH. Return the new class. The shared class is
+// not used.
+return new_ik;
+}
+// Adjust methods to recover missing data.  They need addresses for
+// interpreter entry points and their default native method address
+// must be reset.
+// Updating methods must be done under a lock so multiple
+// threads don't update these in parallel
+//
+// Shared classes are all currently loaded by either the bootstrap or
+// internal parallel class loaders, so this will never cause a deadlock
+// on a custom class loader lock.
+ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
+{
+HandleMark hm(THREAD);
+Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
+check_loader_lock_contention(lockObject, THREAD);
+ObjectLocker ol(lockObject, THREAD, true);
+// prohibited package check assumes all classes loaded from archive call
+// restore_unshareable_info which calls ik->set_package()
+ik->restore_unshareable_info(loader_data, protection_domain, CHECK_NULL);
+}
+ik->print_class_load_logging(loader_data, NULL, NULL);
+// For boot loader, ensure that GetSystemPackage knows that a class in this
+// package was loaded.
+if (class_loader.is_null()) {
+int path_index = ik->shared_classpath_index();
+ResourceMark rm;
+ClassLoader::add_package(ik->name()->as_C_string(), path_index, THREAD);
+}
+if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
+// Only dump the classes that can be stored into CDS archive
+if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
+ResourceMark rm(THREAD);
+classlist_file->print_cr("%s", ik->name()->as_C_string());
+classlist_file->flush();
+}
+}
+// notify a class loaded from shared object
+ClassLoadingService::notify_class_loaded(ik, true /* shared class */);
+}
+ik->set_has_passed_fingerprint_check(false);
+if (UseAOT && ik->supers_have_passed_fingerprint_checks()) {
+uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik);
+uint64_t cds_fp = ik->get_stored_fingerprint();
+if (aot_fp != 0 && aot_fp == cds_fp) {
+// This class matches with a class saved in an AOT library
+ik->set_has_passed_fingerprint_check(true);
+} else {
+ResourceMark rm;
+log_info(class, fingerprint)("%s :  expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp);
+}
+}
+return ik;
+}
+void SystemDictionary::clear_invoke_method_table() {
+SymbolPropertyEntry* spe = NULL;
+for (int index = 0; index < _invoke_method_table->table_size(); index++) {
+SymbolPropertyEntry* p = _invoke_method_table->bucket(index);
+while (p != NULL) {
+spe = p;
+p = p->next();
+_invoke_method_table->free_entry(spe);
+}
+}
+}
+#endif // INCLUDE_CDS
+InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
+if (class_loader.is_null()) {
+ResourceMark rm;
+PackageEntry* pkg_entry = NULL;
+bool search_only_bootloader_append = false;
+ClassLoaderData *loader_data = class_loader_data(class_loader);
+// Find the package in the boot loader's package entry table.
+TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK_NULL);
+if (pkg_name != NULL) {
+pkg_entry = loader_data->packages()->lookup_only(pkg_name);
+}
+// Prior to attempting to load the class, enforce the boot loader's
+// visibility boundaries.
+if (!Universe::is_module_initialized()) {
+// During bootstrapping, prior to module initialization, any
+// class attempting to be loaded must be checked against the
+// java.base packages in the boot loader's PackageEntryTable.
+// No class outside of java.base is allowed to be loaded during
+// this bootstrapping window.
+if (!DumpSharedSpaces) {
+if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
+// Class is either in the unnamed package or in
+// a named package within the unnamed module.  Either
+// case is outside of java.base, do not attempt to
+// load the class post java.base definition.  If
+// java.base has not been defined, let the class load
+// and its package will be checked later by
+// ModuleEntryTable::verify_javabase_packages.
+if (ModuleEntryTable::javabase_defined()) {
+return NULL;
+}
+} else {
+// Check that the class' package is defined within java.base.
+ModuleEntry* mod_entry = pkg_entry->module();
+Symbol* mod_entry_name = mod_entry->name();
+if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) {
+return NULL;
+}
+}
+}
+} else {
+// After the module system has been initialized, check if the class'
+// package is in a module defined to the boot loader.
+if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
+// Class is either in the unnamed package, in a named package
+// within a module not defined to the boot loader or in a
+// a named package within the unnamed module.  In all cases,
+// limit visibility to search for the class only in the boot
+// loader's append path.
+search_only_bootloader_append = true;
+}
+}
+// Prior to bootstrapping's module initialization, never load a class outside
+// of the boot loader's module path
+assert(Universe::is_module_initialized() || DumpSharedSpaces ||
+!search_only_bootloader_append,
+"Attempt to load a class outside of boot loader's module path");
+// Search the shared system dictionary for classes preloaded into the
+// shared spaces.
+InstanceKlass* k = NULL;
+{
+#if INCLUDE_CDS
+PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
+k = load_shared_class(class_name, class_loader, THREAD);
+#endif
+}
+if (k == NULL) {
+// Use VM class loader
+PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
+k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL);
+}
+// find_or_define_instance_class may return a different InstanceKlass
+if (k != NULL) {
+InstanceKlass* defined_k =
+find_or_define_instance_class(class_name, class_loader, k, THREAD);
+if (!HAS_PENDING_EXCEPTION && defined_k != k) {
+// If a parallel capable class loader already defined this class, register 'k' for cleanup.
+assert(defined_k != NULL, "Should have a klass if there's no exception");
+loader_data->add_to_deallocate_list(k);
+k = defined_k;
+} else if (HAS_PENDING_EXCEPTION) {
+loader_data->add_to_deallocate_list(k);
+return NULL;
+}
+}
+return k;
+} else {
+// Use user specified class loader to load class. Call loadClass operation on class_loader.
+ResourceMark rm(THREAD);
+assert(THREAD->is_Java_thread(), "must be a JavaThread");
+JavaThread* jt = (JavaThread*) THREAD;
+PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
+ClassLoader::perf_app_classload_selftime(),
+ClassLoader::perf_app_classload_count(),
+jt->get_thread_stat()->perf_recursion_counts_addr(),
+jt->get_thread_stat()->perf_timers_addr(),
+PerfClassTraceTime::CLASS_LOAD);
+Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL);
+// Translate to external class name format, i.e., convert '/' chars to '.'
+Handle string = java_lang_String::externalize_classname(s, CHECK_NULL);
+JavaValue result(T_OBJECT);
+InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass();
+// Call public unsynchronized loadClass(String) directly for all class loaders
+// for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will
+// acquire a class-name based lock rather than the class loader object lock.
+// JDK < 7 already acquire the class loader lock in loadClass(String, boolean),
+// 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_NULL);
+} else {
+JavaCalls::call_virtual(&result,
+class_loader,
+spec_klass,
+vmSymbols::loadClass_name(),
+vmSymbols::string_class_signature(),
+string,
+CHECK_NULL);
+}
+assert(result.get_type() == T_OBJECT, "just checking");
+oop obj = (oop) result.get_jobject();
+// Primitive classes return null since forName() can not be
+// used to obtain any of the Class objects representing primitives or void
+if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
+InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj));
+// For user defined Java class loaders, check that the name returned is
+// the same as that requested.  This check is done for the bootstrap
+// loader when parsing the class file.
+if (class_name == k->name()) {
+return k;
+}
+}
+// Class is not found or has the wrong name, return NULL
+return NULL;
+}
+}
+void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) {
+HandleMark hm(THREAD);
+ClassLoaderData* loader_data = k->class_loader_data();
+Handle class_loader_h(THREAD, loader_data->class_loader());
+// for bootstrap and other parallel classloaders don't acquire lock,
+// use placeholder token
+// If a parallelCapable class loader calls define_instance_class instead of
+// find_or_define_instance_class to get here, we have a timing
+// hole with systemDictionary updates and check_constraints
+if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
+assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
+compute_loader_lock_object(class_loader_h, THREAD)),
+"define called without lock");
+}
+// Check class-loading constraints. Throw exception if violation is detected.
+// Grabs and releases SystemDictionary_lock
+// The check_constraints/find_class call and update_dictionary sequence
+// must be "atomic" for a specific class/classloader pair so we never
+// define two different instanceKlasses for that class/classloader pair.
+// Existing classloaders will call define_instance_class with the
+// classloader lock held
+// Parallel classloaders will call find_or_define_instance_class
+// which will require a token to perform the define class
+Symbol*  name_h = k->name();
+Dictionary* dictionary = loader_data->dictionary();
+unsigned int d_hash = dictionary->compute_hash(name_h);
+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).
+// JVMTI FollowReferences needs to find the classes this way.
+if (k->class_loader() != NULL) {
+methodHandle m(THREAD, Universe::loader_addClass_method());
+JavaValue result(T_VOID);
+JavaCallArguments args(class_loader_h);
+args.push_oop(Handle(THREAD, k->java_mirror()));
+JavaCalls::call(&result, m, &args, CHECK);
+}
+// Add the new class. We need recompile lock during update of CHA.
+{
+unsigned int p_hash = placeholders()->compute_hash(name_h);
+int p_index = placeholders()->hash_to_index(p_hash);
+MutexLocker mu_r(Compile_lock, THREAD);
+// Add to class hierarchy, initialize vtables, and do possible
+// deoptimizations.
+add_to_hierarchy(k, CHECK); // No exception, but can block
+// Add to systemDictionary - so other classes can see it.
+// Grabs and releases SystemDictionary_lock
+update_dictionary(d_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);
+}
+class_define_event(k, loader_data);
+}
+// Support parallel classloading
+// All parallel class loaders, including bootstrap classloader
+// lock a placeholder entry for this class/class_loader pair
+// to allow parallel defines of different classes for this class loader
+// With AllowParallelDefine flag==true, in case they do not synchronize around
+// FindLoadedClass/DefineClass, calls, we check for parallel
+// loading for them, wait if a defineClass is in progress
+// and return the initial requestor's results
+// This flag does not apply to the bootstrap classloader.
+// With AllowParallelDefine flag==false, call through to define_instance_class
+// which will throw LinkageError: duplicate class definition.
+// False is the requested default.
+// For better performance, the class loaders should synchronize
+// findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
+// potentially waste time reading and parsing the bytestream.
+// Note: VM callers should ensure consistency of k/class_name,class_loader
+// Be careful when modifying this code: once you have run
+// placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS),
+// you need to find_and_remove it before returning.
+// So be careful to not exit with a CHECK_ macro betweeen these calls.
+InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader,
+InstanceKlass* k, TRAPS) {
+Symbol*  name_h = k->name(); // passed in class_name may be null
+ClassLoaderData* loader_data = class_loader_data(class_loader);
+Dictionary* dictionary = loader_data->dictionary();
+unsigned int d_hash = dictionary->compute_hash(name_h);
+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);
+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))) {
+InstanceKlass* check = find_class(d_index, d_hash, name_h, dictionary);
+if (check != NULL) {
+return check;
+}
+}
+// Acquire define token for this class/classloader
+probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
+// Wait if another thread defining in parallel
+// All threads wait - even those that will throw duplicate class: otherwise
+// caller is surprised by LinkageError: duplicate, but findLoadedClass fails
+// if other thread has not finished updating dictionary
+while (probe->definer() != NULL) {
+SystemDictionary_lock->wait();
+}
+// Only special cases allow parallel defines and can use other thread's results
+// Other cases fall through, and may run into duplicate defines
+// caught by finding an entry in the SystemDictionary
+if ((UnsyncloadClass || is_parallelDefine(class_loader)) && (probe->instance_klass() != NULL)) {
+placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
+SystemDictionary_lock->notify_all();
+#ifdef ASSERT
+InstanceKlass* check = find_class(d_index, d_hash, name_h, dictionary);
+assert(check != NULL, "definer missed recording success");
+#endif
+return probe->instance_klass();
+} else {
+// This thread will define the class (even if earlier thread tried and had an error)
+probe->set_definer(THREAD);
+}
+}
+define_instance_class(k, THREAD);
+Handle linkage_exception = Handle(); // null handle
+// definer must notify any waiting threads
+{
+MutexLocker mu(SystemDictionary_lock, THREAD);
+PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
+assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
+if (probe != NULL) {
+if (HAS_PENDING_EXCEPTION) {
+linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
+CLEAR_PENDING_EXCEPTION;
+} else {
+probe->set_instance_klass(k);
+}
+probe->set_definer(NULL);
+placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
+SystemDictionary_lock->notify_all();
+}
+}
+// Can't throw exception while holding lock due to rank ordering
+if (linkage_exception() != NULL) {
+THROW_OOP_(linkage_exception(), NULL); // throws exception and returns
+}
+return k;
+}
+Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
+// If class_loader is NULL we synchronize on _system_loader_lock_obj
+if (class_loader.is_null()) {
+return Handle(THREAD, _system_loader_lock_obj);
+} else {
+return class_loader;
+}
+}
+// This method is added to check how often we have to wait to grab loader
+// lock. The results are being recorded in the performance counters defined in
+// ClassLoader::_sync_systemLoaderLockContentionRate and
+// ClassLoader::_sync_nonSystemLoaderLockConteionRate.
+void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
+if (!UsePerfData) {
+return;
+}
+assert(!loader_lock.is_null(), "NULL lock object");
+if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
+== ObjectSynchronizer::owner_other) {
+// contention will likely happen, so increment the corresponding
+// contention counter.
+if (loader_lock() == _system_loader_lock_obj) {
+ClassLoader::sync_systemLoaderLockContentionRate()->inc();
+} else {
+ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
+}
+}
+}
+// ----------------------------------------------------------------------------
+// Lookup
+InstanceKlass* SystemDictionary::find_class(int index, unsigned int hash,
+Symbol* class_name,
+Dictionary* dictionary) {
+assert_locked_or_safepoint(SystemDictionary_lock);
+return dictionary->find_class(index, hash, class_name);
+}
+// Basic find on classes in the midst of being loaded
+Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
+ClassLoaderData* loader_data) {
+assert_locked_or_safepoint(SystemDictionary_lock);
+unsigned int p_hash = placeholders()->compute_hash(class_name);
+int p_index = placeholders()->hash_to_index(p_hash);
+return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
+}
+// Used for assertions and verification only
+// Precalculating the hash and index is an optimization because there are many lookups
+// before adding the class.
+InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
+assert_locked_or_safepoint(SystemDictionary_lock);
+#ifndef ASSERT
+guarantee(VerifyBeforeGC      ||
+VerifyDuringGC      ||
+VerifyBeforeExit    ||
+VerifyDuringStartup ||
+VerifyAfterGC, "too expensive");
+#endif
+Dictionary* dictionary = loader_data->dictionary();
+unsigned int d_hash = dictionary->compute_hash(class_name);
+int d_index = dictionary->hash_to_index(d_hash);
+return find_class(d_index, d_hash, class_name, dictionary);
+}
+// ----------------------------------------------------------------------------
+// Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
+// is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
+// before a new class is used.
+void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) {
+assert(k != NULL, "just checking");
+assert_locked_or_safepoint(Compile_lock);
+// Link into hierachy. Make sure the vtables are initialized before linking into
+k->append_to_sibling_list();                    // add to superklass/sibling list
+k->process_interfaces(THREAD);                  // handle all "implements" declarations
+k->set_init_state(InstanceKlass::loaded);
+// Now flush all code that depended on old class hierarchy.
+// Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
+// Also, first reinitialize vtable because it may have gotten out of synch
+// while the new class wasn't connected to the class hierarchy.
+CodeCache::flush_dependents_on(k);
+}
+// ----------------------------------------------------------------------------
+// GC support
+void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
+roots_oops_do(blk, NULL);
+}
+#ifdef ASSERT
+class VerifySDReachableAndLiveClosure : public OopClosure {
+private:
+BoolObjectClosure* _is_alive;
+template <class T> void do_oop_work(T* p) {
+oop obj = oopDesc::load_decode_heap_oop(p);
+guarantee(_is_alive->do_object_b(obj), "Oop in protection domain cache table must be live");
+}
+public:
+VerifySDReachableAndLiveClosure(BoolObjectClosure* is_alive) : OopClosure(), _is_alive(is_alive) { }
+virtual void do_oop(oop* p)       { do_oop_work(p); }
+virtual void do_oop(narrowOop* p) { do_oop_work(p); }
+};
+#endif
+// Assumes classes in the SystemDictionary are only unloaded at a safepoint
+// Note: anonymous classes are not in the SD.
+bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive,
+GCTimer* gc_timer,
+bool do_cleaning) {
+bool unloading_occurred;
+{
+GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer);
+// First, mark for unload all ClassLoaderData referencing a dead class loader.
+unloading_occurred = ClassLoaderDataGraph::do_unloading(is_alive,
+do_cleaning);
+}
+if (unloading_occurred) {
+GCTraceTime(Debug, gc, phases) t("Dictionary", gc_timer);
+constraints()->purge_loader_constraints();
+resolution_errors()->purge_resolution_errors();
+}
+{
+GCTraceTime(Debug, gc, phases) t("ProtectionDomainCacheTable", gc_timer);
+// Oops referenced by the protection domain cache table may get unreachable independently
+// of the class loader (eg. cached protection domain oops). So we need to
+// explicitly unlink them here.
+_pd_cache_table->unlink(is_alive);
+#ifdef ASSERT
+VerifySDReachableAndLiveClosure cl(is_alive);
+_pd_cache_table->oops_do(&cl);
+#endif
+}
+if (do_cleaning) {
+GCTraceTime(Debug, gc, phases) t("ResolvedMethodTable", gc_timer);
+ResolvedMethodTable::unlink(is_alive);
+}
+return unloading_occurred;
+}
+void SystemDictionary::roots_oops_do(OopClosure* strong, OopClosure* weak) {
+strong->do_oop(&_java_system_loader);
+strong->do_oop(&_system_loader_lock_obj);
+CDS_ONLY(SystemDictionaryShared::roots_oops_do(strong);)
+// Do strong roots marking if the closures are the same.
+if (strong == weak || !ClassUnloading) {
+// Only the protection domain oops contain references into the heap. Iterate
+// over all of them.
+_pd_cache_table->oops_do(strong);
+} else {
+if (weak != NULL) {
+_pd_cache_table->oops_do(weak);
+}
+}
+// Visit extra methods
+invoke_method_table()->oops_do(strong);
+if (weak != NULL) {
+ResolvedMethodTable::oops_do(weak);
+}
+}
+void SystemDictionary::oops_do(OopClosure* f) {
+f->do_oop(&_java_system_loader);
+f->do_oop(&_system_loader_lock_obj);
+CDS_ONLY(SystemDictionaryShared::oops_do(f);)
+// Only the protection domain oops contain references into the heap. Iterate
+// over all of them.
+_pd_cache_table->oops_do(f);
+// Visit extra methods
+invoke_method_table()->oops_do(f);
+ResolvedMethodTable::oops_do(f);
+}
+// CDS: scan and relocate all classes in the system dictionary.
+void SystemDictionary::classes_do(MetaspaceClosure* it) {
+ClassLoaderData::the_null_class_loader_data()->dictionary()->classes_do(it);
+}
+// CDS: scan and relocate all classes referenced by _well_known_klasses[].
+void SystemDictionary::well_known_klasses_do(MetaspaceClosure* it) {
+for (int id = FIRST_WKID; id < WKID_LIMIT; id++) {
+it->push(well_known_klass_addr((WKID)id));
+}
+}
+void SystemDictionary::methods_do(void f(Method*)) {
+// Walk methods in loaded classes
+ClassLoaderDataGraph::methods_do(f);
+// Walk method handle intrinsics
+invoke_method_table()->methods_do(f);
+}
+class RemoveClassesClosure : public CLDClosure {
+public:
+void do_cld(ClassLoaderData* cld) {
+if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) {
+cld->dictionary()->remove_classes_in_error_state();
+}
+}
+};
+void SystemDictionary::remove_classes_in_error_state() {
+ClassLoaderData::the_null_class_loader_data()->dictionary()->remove_classes_in_error_state();
+RemoveClassesClosure rcc;
+ClassLoaderDataGraph::cld_do(&rcc);
+}
+// ----------------------------------------------------------------------------
+// Lazily load klasses
+void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
+// if multiple threads calling this function, only one thread will load
+// the class.  The other threads will find the loaded version once the
+// class is loaded.
+Klass* aos = _abstract_ownable_synchronizer_klass;
+if (aos == NULL) {
+Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
+// Force a fence to prevent any read before the write completes
+OrderAccess::fence();
+_abstract_ownable_synchronizer_klass = InstanceKlass::cast(k);
+}
+}
+// ----------------------------------------------------------------------------
+// Initialization
+void SystemDictionary::initialize(TRAPS) {
+// Allocate arrays
+_placeholders        = new PlaceholderTable(_placeholder_table_size);
+_number_of_modifications = 0;
+_loader_constraints  = new LoaderConstraintTable(_loader_constraint_size);
+_resolution_errors   = new ResolutionErrorTable(_resolution_error_size);
+_invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
+_pd_cache_table = new ProtectionDomainCacheTable(defaultProtectionDomainCacheSize);
+// Allocate private object used as system class loader lock
+_system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
+// Initialize basic classes
+initialize_preloaded_classes(CHECK);
+}
+// Compact table of directions on the initialization of klasses:
+static const short wk_init_info[] = {
+#define WK_KLASS_INIT_INFO(name, symbol, option) \
+( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
+<< SystemDictionary::CEIL_LG_OPTION_LIMIT) \
+| (int)SystemDictionary::option ),
+WK_KLASSES_DO(WK_KLASS_INIT_INFO)
+#undef WK_KLASS_INIT_INFO
+0
+};
+bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
+assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
+int  info = wk_init_info[id - FIRST_WKID];
+int  sid  = (info >> CEIL_LG_OPTION_LIMIT);
+Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
+InstanceKlass** klassp = &_well_known_klasses[id];
+bool must_load;
+#if INCLUDE_JVMCI
+if (EnableJVMCI) {
+// If JVMCI is enabled we require its classes to be found.
+must_load = (init_opt < SystemDictionary::Opt) || (init_opt == SystemDictionary::Jvmci);
+} else
+#endif
+{
+must_load = (init_opt < SystemDictionary::Opt);
+}
+if ((*klassp) == NULL) {
+Klass* k;
+if (must_load) {
+k = resolve_or_fail(symbol, true, CHECK_0); // load required class
+} else {
+k = resolve_or_null(symbol,       CHECK_0); // load optional klass
+}
+(*klassp) = (k == NULL) ? NULL : InstanceKlass::cast(k);
+}
+return ((*klassp) != NULL);
+}
+void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
+assert((int)start_id <= (int)limit_id, "IDs are out of order!");
+for (int id = (int)start_id; id < (int)limit_id; id++) {
+assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
+int info = wk_init_info[id - FIRST_WKID];
+int sid  = (info >> CEIL_LG_OPTION_LIMIT);
+int opt  = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
+initialize_wk_klass((WKID)id, opt, CHECK);
+}
+// move the starting value forward to the limit:
+start_id = limit_id;
+}
+void SystemDictionary::initialize_preloaded_classes(TRAPS) {
+assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
+// Create the ModuleEntry for java.base.  This call needs to be done here,
+// after vmSymbols::initialize() is called but before any classes are pre-loaded.
+ClassLoader::classLoader_init2(CHECK);
+// Preload commonly used klasses
+WKID scan = FIRST_WKID;
+// first do Object, then String, Class
+#if INCLUDE_CDS
+if (UseSharedSpaces) {
+initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
+// Initialize the constant pool for the Object_class
+Object_klass()->constants()->restore_unshareable_info(CHECK);
+initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
+} else
+#endif
+{
+initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
+}
+// Calculate offsets for String and Class classes since they are loaded and
+// can be used after this point.
+java_lang_String::compute_offsets();
+java_lang_Class::compute_offsets();
+// Fixup mirrors for classes loaded before java.lang.Class.
+// These calls iterate over the objects currently in the perm gen
+// so calling them at this point is matters (not before when there
+// are fewer objects and not later after there are more objects
+// in the perm gen.
+Universe::initialize_basic_type_mirrors(CHECK);
+Universe::fixup_mirrors(CHECK);
+// do a bunch more:
+initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
+// Preload ref klasses and set reference types
+InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
+InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
+initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
+InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
+InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
+InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
+InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
+// JSR 292 classes
+WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
+WKID jsr292_group_end   = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
+initialize_wk_klasses_until(jsr292_group_start, scan, CHECK);
+initialize_wk_klasses_through(jsr292_group_end, scan, CHECK);
+initialize_wk_klasses_until(NOT_JVMCI(WKID_LIMIT) JVMCI_ONLY(FIRST_JVMCI_WKID), scan, CHECK);
+_box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
+_box_klasses[T_CHAR]    = WK_KLASS(Character_klass);
+_box_klasses[T_FLOAT]   = WK_KLASS(Float_klass);
+_box_klasses[T_DOUBLE]  = WK_KLASS(Double_klass);
+_box_klasses[T_BYTE]    = WK_KLASS(Byte_klass);
+_box_klasses[T_SHORT]   = WK_KLASS(Short_klass);
+_box_klasses[T_INT]     = WK_KLASS(Integer_klass);
+_box_klasses[T_LONG]    = WK_KLASS(Long_klass);
+//_box_klasses[T_OBJECT]  = WK_KLASS(object_klass);
+//_box_klasses[T_ARRAY]   = WK_KLASS(object_klass);
+{ // Compute whether we should use loadClass or loadClassInternal when loading classes.
+Method* 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
+Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
+_has_checkPackageAccess = (method != NULL);
+}
+}
+// Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
+// If so, returns the basic type it holds.  If not, returns T_OBJECT.
+BasicType SystemDictionary::box_klass_type(Klass* k) {
+assert(k != NULL, "");
+for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
+if (_box_klasses[i] == k)
+return (BasicType)i;
+}
+return T_OBJECT;
+}
+// Constraints on class loaders. The details of the algorithm can be
+// found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
+// Virtual Machine" by Sheng Liang and Gilad Bracha.  The basic idea is
+// that the dictionary needs to maintain a set of contraints that
+// must be satisfied by all classes in the dictionary.
+// if defining is true, then LinkageError if already in dictionary
+// if initiating loader, then ok if InstanceKlass matches existing entry
+void SystemDictionary::check_constraints(int d_index, unsigned int d_hash,
+InstanceKlass* k,
+Handle class_loader, bool defining,
+TRAPS) {
+const char *linkage_error1 = NULL;
+const char *linkage_error2 = NULL;
+{
+Symbol*  name  = k->name();
+ClassLoaderData *loader_data = class_loader_data(class_loader);
+MutexLocker mu(SystemDictionary_lock, THREAD);
+InstanceKlass* check = find_class(d_index, d_hash, name, loader_data->dictionary());
+if (check != NULL) {
+// if different InstanceKlass - duplicate class definition,
+// else - ok, class loaded by a different thread in parallel,
+// we should only have found it if it was done loading and ok to use
+// dictionary only holds instance classes, placeholders
+// also holds array classes
+assert(check->is_instance_klass(), "noninstance in systemdictionary");
+if ((defining == true) || (k != check)) {
+linkage_error1 = "loader (instance of ";
+linkage_error2 = "): attempted duplicate class definition for name: \"";
+} else {
+return;
+}
+}
+#ifdef ASSERT
+Symbol* ph_check = find_placeholder(name, loader_data);
+assert(ph_check == NULL || ph_check == name, "invalid symbol");
+#endif
+if (linkage_error1 == NULL) {
+if (constraints()->check_or_update(k, class_loader, name) == false) {
+linkage_error1 = "loader constraint violation: loader (instance of ";
+linkage_error2 = ") previously initiated loading for a different type with name \"";
+}
+}
+}
+// Throw error now if needed (cannot throw while holding
+// SystemDictionary_lock because of rank ordering)
+if (linkage_error1) {
+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_error1) + strlen(class_loader_name) +
+strlen(linkage_error2) + strlen(type_name) + 2; // +2 for '"' and null byte.
+char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
+jio_snprintf(buf, buflen, "%s%s%s%s\"", linkage_error1, class_loader_name, linkage_error2, type_name);
+THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
+}
+}
+// Update class loader data 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,
+InstanceKlass* k,
+Handle class_loader,
+TRAPS) {
+// Compile_lock prevents systemDictionary updates during compilations
+assert_locked_or_safepoint(Compile_lock);
+Symbol*  name  = k->name();
+ClassLoaderData *loader_data = class_loader_data(class_loader);
+{
+MutexLocker mu1(SystemDictionary_lock, THREAD);
+// See whether biased locking is enabled and if so set it for this
+// klass.
+// Note that this must be done past the last potential blocking
+// point / safepoint. We enable biased locking lazily using a
+// VM_Operation to iterate the SystemDictionary and installing the
+// biasable mark word into each InstanceKlass's prototype header.
+// To avoid race conditions where we accidentally miss enabling the
+// optimization for one class in the process of being added to the
+// dictionary, we must not safepoint after the test of
+// BiasedLocking::enabled().
+if (UseBiasedLocking && BiasedLocking::enabled()) {
+// Set biased locking bit for all loaded classes; it will be
+// cleared if revocation occurs too often for this type
+// NOTE that we must only do this when the class is initally
+// defined, not each time it is referenced from a new class loader
+if (k->class_loader() == class_loader()) {
+k->set_prototype_header(markOopDesc::biased_locking_prototype());
+}
+}
+// Make a new dictionary entry.
+Dictionary* dictionary = loader_data->dictionary();
+InstanceKlass* sd_check = find_class(d_index, d_hash, name, dictionary);
+if (sd_check == NULL) {
+dictionary->add_klass(d_index, d_hash, name, k);
+notice_modification();
+}
+#ifdef ASSERT
+sd_check = find_class(d_index, d_hash, name, dictionary);
+assert (sd_check != NULL, "should have entry in dictionary");
+// Note: there may be a placeholder entry: for circularity testing
+// or for parallel defines
+#endif
+SystemDictionary_lock->notify_all();
+}
+}
+// Try to find a class name using the loader constraints.  The
+// loader constraints might know about a class that isn't fully loaded
+// yet and these will be ignored.
+Klass* SystemDictionary::find_constrained_instance_or_array_klass(
+Symbol* class_name, Handle class_loader, TRAPS) {
+// First see if it has been loaded directly.
+// Force the protection domain to be null.  (This removes protection checks.)
+Handle no_protection_domain;
+Klass* klass = find_instance_or_array_klass(class_name, class_loader,
+no_protection_domain, CHECK_NULL);
+if (klass != NULL)
+return klass;
+// Now look to see if it has been loaded elsewhere, and is subject to
+// a loader constraint that would require this loader to return the
+// klass that is already loaded.
+if (FieldType::is_array(class_name)) {
+// For array classes, their Klass*s are not kept in the
+// constraint table. The element Klass*s are.
+FieldArrayInfo fd;
+BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
+if (t != T_OBJECT) {
+klass = Universe::typeArrayKlassObj(t);
+} else {
+MutexLocker mu(SystemDictionary_lock, THREAD);
+klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
+}
+// If element class already loaded, allocate array klass
+if (klass != NULL) {
+klass = klass->array_klass_or_null(fd.dimension());
+}
+} else {
+MutexLocker mu(SystemDictionary_lock, THREAD);
+// Non-array classes are easy: simply check the constraint table.
+klass = constraints()->find_constrained_klass(class_name, class_loader);
+}
+return klass;
+}
+bool SystemDictionary::add_loader_constraint(Symbol* class_name,
+Handle class_loader1,
+Handle class_loader2,
+Thread* THREAD) {
+ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
+ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
+Symbol* constraint_name = NULL;
+if (!FieldType::is_array(class_name)) {
+constraint_name = class_name;
+} else {
+// For array classes, their Klass*s are not kept in the
+// constraint table. The element classes are.
+FieldArrayInfo fd;
+BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
+// primitive types always pass
+if (t != T_OBJECT) {
+return true;
+} else {
+constraint_name = fd.object_key();
+}
+}
+Dictionary* dictionary1 = loader_data1->dictionary();
+unsigned int d_hash1 = dictionary1->compute_hash(constraint_name);
+int d_index1 = dictionary1->hash_to_index(d_hash1);
+Dictionary* dictionary2 = loader_data2->dictionary();
+unsigned int d_hash2 = dictionary2->compute_hash(constraint_name);
+int d_index2 = dictionary2->hash_to_index(d_hash2);
+{
+MutexLocker mu_s(SystemDictionary_lock, THREAD);
+InstanceKlass* klass1 = find_class(d_index1, d_hash1, constraint_name, dictionary1);
+InstanceKlass* klass2 = find_class(d_index2, d_hash2, constraint_name, dictionary2);
+return constraints()->add_entry(constraint_name, klass1, class_loader1,
+klass2, class_loader2);
+}
+}
+// Add entry to resolution error table to record the error when the first
+// attempt to resolve a reference to a class has failed.
+void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which,
+Symbol* error, Symbol* message) {
+unsigned int hash = resolution_errors()->compute_hash(pool, which);
+int index = resolution_errors()->hash_to_index(hash);
+{
+MutexLocker ml(SystemDictionary_lock, Thread::current());
+resolution_errors()->add_entry(index, hash, pool, which, error, message);
+}
+}
+// Delete a resolution error for RedefineClasses for a constant pool is going away
+void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
+resolution_errors()->delete_entry(pool);
+}
+// Lookup resolution error table. Returns error if found, otherwise NULL.
+Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which,
+Symbol** message) {
+unsigned int hash = resolution_errors()->compute_hash(pool, which);
+int index = resolution_errors()->hash_to_index(hash);
+{
+MutexLocker ml(SystemDictionary_lock, Thread::current());
+ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
+if (entry != NULL) {
+*message = entry->message();
+return entry->error();
+} else {
+return NULL;
+}
+}
+}
+// Signature constraints ensure that callers and callees agree about
+// the meaning of type names in their signatures.  This routine is the
+// intake for constraints.  It collects them from several places:
+//
+//  * LinkResolver::resolve_method (if check_access is true) requires
+//    that the resolving class (the caller) and the defining class of
+//    the resolved method (the callee) agree on each type in the
+//    method's signature.
+//
+//  * LinkResolver::resolve_interface_method performs exactly the same
+//    checks.
+//
+//  * LinkResolver::resolve_field requires that the constant pool
+//    attempting to link to a field agree with the field's defining
+//    class about the type of the field signature.
+//
+//  * klassVtable::initialize_vtable requires that, when a class
+//    overrides a vtable entry allocated by a superclass, that the
+//    overriding method (i.e., the callee) agree with the superclass
+//    on each type in the method's signature.
+//
+//  * klassItable::initialize_itable requires that, when a class fills
+//    in its itables, for each non-abstract method installed in an
+//    itable, the method (i.e., the callee) agree with the interface
+//    on each type in the method's signature.
+//
+// All those methods have a boolean (check_access, checkconstraints)
+// which turns off the checks.  This is used from specialized contexts
+// such as bootstrapping, dumping, and debugging.
+//
+// No direct constraint is placed between the class and its
+// supertypes.  Constraints are only placed along linked relations
+// between callers and callees.  When a method overrides or implements
+// an abstract method in a supertype (superclass or interface), the
+// constraints are placed as if the supertype were the caller to the
+// overriding method.  (This works well, since callers to the
+// supertype have already established agreement between themselves and
+// the supertype.)  As a result of all this, a class can disagree with
+// its supertype about the meaning of a type name, as long as that
+// class neither calls a relevant method of the supertype, nor is
+// called (perhaps via an override) from the supertype.
+//
+//
+// SystemDictionary::check_signature_loaders(sig, l1, l2)
+//
+// Make sure all class components (including arrays) in the given
+// signature will be resolved to the same class in both loaders.
+// Returns the name of the type that failed a loader constraint check, or
+// NULL if no constraint failed.  No exception except OOME is thrown.
+// Arrays are not added to the loader constraint table, their elements are.
+Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
+Handle loader1, Handle loader2,
+bool is_method, TRAPS)  {
+// Nothing to do if loaders are the same.
+if (loader1() == loader2()) {
+return NULL;
+}
+SignatureStream sig_strm(signature, is_method);
+while (!sig_strm.is_done()) {
+if (sig_strm.is_object()) {
+Symbol* sig = sig_strm.as_symbol(CHECK_NULL);
+if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
+return sig;
+}
+}
+sig_strm.next();
+}
+return NULL;
+}
+methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
+Symbol* signature,
+TRAPS) {
+methodHandle empty;
+assert(MethodHandles::is_signature_polymorphic(iid) &&
+MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
+iid != vmIntrinsics::_invokeGeneric,
+"must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid));
+unsigned int hash  = invoke_method_table()->compute_hash(signature, iid);
+int          index = invoke_method_table()->hash_to_index(hash);
+SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
+methodHandle m;
+if (spe == NULL || spe->method() == NULL) {
+spe = NULL;
+// Must create lots of stuff here, but outside of the SystemDictionary lock.
+m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
+if (!Arguments::is_interpreter_only()) {
+// Generate a compiled form of the MH intrinsic.
+AdapterHandlerLibrary::create_native_wrapper(m);
+// Check if have the compiled code.
+if (!m->has_compiled_code()) {
+THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(),
+"Out of space in CodeCache for method handle intrinsic", empty);
+}
+}
+// Now grab the lock.  We might have to throw away the new method,
+// if a racing thread has managed to install one at the same time.
+{
+MutexLocker ml(SystemDictionary_lock, THREAD);
+spe = invoke_method_table()->find_entry(index, hash, signature, iid);
+if (spe == NULL)
+spe = invoke_method_table()->add_entry(index, hash, signature, iid);
+if (spe->method() == NULL)
+spe->set_method(m());
+}
+}
+assert(spe != NULL && spe->method() != NULL, "");
+assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
+spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
+"MH intrinsic invariant");
+return spe->method();
+}
+// Helper for unpacking the return value from linkMethod and linkCallSite.
+static methodHandle unpack_method_and_appendix(Handle mname,
+Klass* accessing_klass,
+objArrayHandle appendix_box,
+Handle* appendix_result,
+TRAPS) {
+methodHandle empty;
+if (mname.not_null()) {
+Method* m = java_lang_invoke_MemberName::vmtarget(mname());
+if (m != NULL) {
+oop appendix = appendix_box->obj_at(0);
+if (TraceMethodHandles) {
+#ifndef PRODUCT
+ttyLocker ttyl;
+tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
+m->print();
+if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
+tty->cr();
+#endif //PRODUCT
+}
+(*appendix_result) = Handle(THREAD, appendix);
+// the target is stored in the cpCache and if a reference to this
+// MethodName is dropped we need a way to make sure the
+// class_loader containing this method is kept alive.
+// FIXME: the appendix might also preserve this dependency.
+ClassLoaderData* this_key = accessing_klass->class_loader_data();
+this_key->record_dependency(m->method_holder(), CHECK_NULL); // Can throw OOM
+return methodHandle(THREAD, m);
+}
+}
+THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
+return empty;
+}
+methodHandle SystemDictionary::find_method_handle_invoker(Klass* klass,
+Symbol* name,
+Symbol* signature,
+Klass* accessing_klass,
+Handle *appendix_result,
+Handle *method_type_result,
+TRAPS) {
+methodHandle empty;
+assert(THREAD->can_call_java() ,"");
+Handle method_type =
+SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
+int ref_kind = JVM_REF_invokeVirtual;
+oop name_oop = StringTable::intern(name, CHECK_(empty));
+Handle name_str (THREAD, name_oop);
+objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
+assert(appendix_box->obj_at(0) == NULL, "");
+// This should not happen.  JDK code should take care of that.
+if (accessing_klass == NULL || method_type.is_null()) {
+THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
+}
+// call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
+JavaCallArguments args;
+args.push_oop(Handle(THREAD, accessing_klass->java_mirror()));
+args.push_int(ref_kind);
+args.push_oop(Handle(THREAD, klass->java_mirror()));
+args.push_oop(name_str);
+args.push_oop(method_type);
+args.push_oop(appendix_box);
+JavaValue result(T_OBJECT);
+JavaCalls::call_static(&result,
+SystemDictionary::MethodHandleNatives_klass(),
+vmSymbols::linkMethod_name(),
+vmSymbols::linkMethod_signature(),
+&args, CHECK_(empty));
+Handle mname(THREAD, (oop) result.get_jobject());
+(*method_type_result) = method_type;
+return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
+}
+// Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
+// We must ensure that all class loaders everywhere will reach this class, for any client.
+// This is a safe bet for public classes in java.lang, such as Object and String.
+// We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
+// Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
+static bool is_always_visible_class(oop mirror) {
+Klass* klass = java_lang_Class::as_Klass(mirror);
+if (klass->is_objArray_klass()) {
+klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
+}
+if (klass->is_typeArray_klass()) {
+return true; // primitive array
+}
+assert(klass->is_instance_klass(), "%s", klass->external_name());
+return klass->is_public() &&
+(InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) ||       // java.lang
+InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass()));  // java.lang.invoke
+}
+// Ask Java code to find or construct a java.lang.invoke.MethodType for the given
+// signature, as interpreted relative to the given class loader.
+// Because of class loader constraints, all method handle usage must be
+// consistent with this loader.
+Handle SystemDictionary::find_method_handle_type(Symbol* signature,
+Klass* accessing_klass,
+TRAPS) {
+Handle empty;
+vmIntrinsics::ID null_iid = vmIntrinsics::_none;  // distinct from all method handle invoker intrinsics
+unsigned int hash  = invoke_method_table()->compute_hash(signature, null_iid);
+int          index = invoke_method_table()->hash_to_index(hash);
+SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
+if (spe != NULL && spe->method_type() != NULL) {
+assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
+return Handle(THREAD, spe->method_type());
+} else if (!THREAD->can_call_java()) {
+warning("SystemDictionary::find_method_handle_type called from compiler thread");  // FIXME
+return Handle();  // do not attempt from within compiler, unless it was cached
+}
+Handle class_loader, protection_domain;
+if (accessing_klass != NULL) {
+class_loader      = Handle(THREAD, accessing_klass->class_loader());
+protection_domain = Handle(THREAD, accessing_klass->protection_domain());
+}
+bool can_be_cached = true;
+int npts = ArgumentCount(signature).size();
+objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty));
+int arg = 0;
+Handle rt; // the return type from the signature
+ResourceMark rm(THREAD);
+for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
+oop mirror = NULL;
+if (can_be_cached) {
+// Use neutral class loader to lookup candidate classes to be placed in the cache.
+mirror = ss.as_java_mirror(Handle(), Handle(),
+SignatureStream::ReturnNull, CHECK_(empty));
+if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) {
+// Fall back to accessing_klass context.
+can_be_cached = false;
+}
+}
+if (!can_be_cached) {
+// Resolve, throwing a real error if it doesn't work.
+mirror = ss.as_java_mirror(class_loader, protection_domain,
+SignatureStream::NCDFError, CHECK_(empty));
+}
+assert(!oopDesc::is_null(mirror), "%s", ss.as_symbol(THREAD)->as_C_string());
+if (ss.at_return_type())
+rt = Handle(THREAD, mirror);
+else
+pts->obj_at_put(arg++, mirror);
+// Check accessibility.
+if (ss.is_object() && accessing_klass != NULL) {
+Klass* sel_klass = java_lang_Class::as_Klass(mirror);
+mirror = NULL;  // safety
+// Emulate ConstantPool::verify_constant_pool_resolve.
+if (sel_klass->is_objArray_klass())
+sel_klass = ObjArrayKlass::cast(sel_klass)->bottom_klass();
+if (sel_klass->is_instance_klass()) {
+LinkResolver::check_klass_accessability(accessing_klass, sel_klass, CHECK_(empty));
+}
+}
+}
+assert(arg == npts, "");
+// call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType
+JavaCallArguments args(Handle(THREAD, rt()));
+args.push_oop(pts);
+JavaValue result(T_OBJECT);
+JavaCalls::call_static(&result,
+SystemDictionary::MethodHandleNatives_klass(),
+vmSymbols::findMethodHandleType_name(),
+vmSymbols::findMethodHandleType_signature(),
+&args, CHECK_(empty));
+Handle method_type(THREAD, (oop) result.get_jobject());
+if (can_be_cached) {
+// We can cache this MethodType inside the JVM.
+MutexLocker ml(SystemDictionary_lock, THREAD);
+spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
+if (spe == NULL)
+spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
+if (spe->method_type() == NULL) {
+spe->set_method_type(method_type());
+}
+}
+// report back to the caller with the MethodType
+return method_type;
+}
+// Ask Java code to find or construct a method handle constant.
+Handle SystemDictionary::link_method_handle_constant(Klass* caller,
+int ref_kind, //e.g., JVM_REF_invokeVirtual
+Klass* callee,
+Symbol* name_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) == '(') {
+type = find_method_handle_type(signature, caller, CHECK_(empty));
+} else if (caller == NULL) {
+// This should not happen.  JDK code should take care of that.
+THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
+} else {
+ResourceMark rm(THREAD);
+SignatureStream ss(signature, false);
+if (!ss.is_done()) {
+oop mirror = ss.as_java_mirror(Handle(THREAD, caller->class_loader()),
+Handle(THREAD, 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(Handle(THREAD, caller->java_mirror()));  // the referring class
+args.push_int(ref_kind);
+args.push_oop(Handle(THREAD, callee->java_mirror()));  // the target class
+args.push_oop(name);
+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.
+methodHandle SystemDictionary::find_dynamic_call_site_invoker(Klass* caller,
+Handle bootstrap_specifier,
+Symbol* name,
+Symbol* type,
+Handle *appendix_result,
+Handle *method_type_result,
+TRAPS) {
+methodHandle empty;
+Handle bsm, info;
+if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
+bsm = bootstrap_specifier;
+} else {
+assert(bootstrap_specifier->is_objArray(), "");
+objArrayHandle args(THREAD, (objArrayOop) bootstrap_specifier());
+int len = args->length();
+assert(len >= 1, "");
+bsm = Handle(THREAD, args->obj_at(0));
+if (len > 1) {
+objArrayOop args1 = oopFactory::new_objArray(SystemDictionary::Object_klass(), len-1, CHECK_(empty));
+for (int i = 1; i < len; i++)
+args1->obj_at_put(i-1, args->obj_at(i));
+info = Handle(THREAD, args1);
+}
+}
+guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
+"caller must supply a valid BSM");
+Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
+Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
+// This should not happen.  JDK code should take care of that.
+if (caller == NULL || method_type.is_null()) {
+THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty);
+}
+objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
+assert(appendix_box->obj_at(0) == NULL, "");
+// call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, bsm, name, mtype, info, &appendix)
+JavaCallArguments args;
+args.push_oop(Handle(THREAD, caller->java_mirror()));
+args.push_oop(bsm);
+args.push_oop(method_name);
+args.push_oop(method_type);
+args.push_oop(info);
+args.push_oop(appendix_box);
+JavaValue result(T_OBJECT);
+JavaCalls::call_static(&result,
+SystemDictionary::MethodHandleNatives_klass(),
+vmSymbols::linkCallSite_name(),
+vmSymbols::linkCallSite_signature(),
+&args, CHECK_(empty));
+Handle mname(THREAD, (oop) result.get_jobject());
+(*method_type_result) = method_type;
+return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
+}
+// Protection domain cache table handling
+ProtectionDomainCacheEntry* SystemDictionary::cache_get(Handle protection_domain) {
+return _pd_cache_table->get(protection_domain);
+}
+void SystemDictionary::reorder_dictionary_for_sharing() {
+ClassLoaderData::the_null_class_loader_data()->dictionary()->reorder_dictionary_for_sharing();
+}
+size_t SystemDictionary::count_bytes_for_buckets() {
+return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_buckets();
+}
+size_t SystemDictionary::count_bytes_for_table() {
+return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_table();
+}
+void SystemDictionary::copy_buckets(char* top, char* end) {
+ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_buckets(top, end);
+}
+void SystemDictionary::copy_table(char* top, char* end) {
+ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_table(top, end);
+}
+// ----------------------------------------------------------------------------
+void SystemDictionary::print_shared(outputStream *st) {
+shared_dictionary()->print_on(st);
+}
+void SystemDictionary::print_on(outputStream *st) {
+if (shared_dictionary() != NULL) {
+st->print_cr("Shared Dictionary");
+shared_dictionary()->print_on(st);
+st->cr();
+}
+GCMutexLocker mu(SystemDictionary_lock);
+ClassLoaderDataGraph::print_dictionary(st);
+// Placeholders
+placeholders()->print_on(st);
+st->cr();
+// loader constraints - print under SD_lock
+constraints()->print_on(st);
+st->cr();
+_pd_cache_table->print_on(st);
+st->cr();
+}
+void SystemDictionary::verify() {
+guarantee(constraints() != NULL,
+"Verify of loader constraints failed");
+guarantee(placeholders()->number_of_entries() >= 0,
+"Verify of placeholders failed");
+GCMutexLocker mu(SystemDictionary_lock);
+// Verify dictionary
+ClassLoaderDataGraph::verify_dictionary();
+placeholders()->verify();
+// Verify constraint table
+guarantee(constraints() != NULL, "Verify of loader constraints failed");
+constraints()->verify(placeholders());
+_pd_cache_table->verify();
+}
+void SystemDictionary::dump(outputStream *st, bool verbose) {
+assert_locked_or_safepoint(SystemDictionary_lock);
+if (verbose) {
+print_on(st);
+} else {
+if (shared_dictionary() != NULL) {
+shared_dictionary()->print_table_statistics(st, "Shared Dictionary");
+}
+ClassLoaderDataGraph::print_dictionary_statistics(st);
+placeholders()->print_table_statistics(st, "Placeholder Table");
+constraints()->print_table_statistics(st, "LoaderConstraints Table");
+_pd_cache_table->print_table_statistics(st, "ProtectionDomainCache Table");
+}
+}
+// Utility for dumping dictionaries.
+SystemDictionaryDCmd::SystemDictionaryDCmd(outputStream* output, bool heap) :
+DCmdWithParser(output, heap),
+_verbose("-verbose", "Dump the content of each dictionary entry for all class loaders",
+"BOOLEAN", false, "false") {
+_dcmdparser.add_dcmd_option(&_verbose);
+}
+void SystemDictionaryDCmd::execute(DCmdSource source, TRAPS) {
+VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSysDict,
+_verbose.value());
+VMThread::execute(&dumper);
+}
+int SystemDictionaryDCmd::num_arguments() {
+ResourceMark rm;
+SystemDictionaryDCmd* dcmd = new SystemDictionaryDCmd(NULL, false);
+if (dcmd != NULL) {
+DCmdMark mark(dcmd);
+return dcmd->_dcmdparser.num_arguments();
+} else {
+return 0;
+}
+}
+class CombineDictionariesClosure : public CLDClosure {
+private:
+Dictionary* _master_dictionary;
+public:
+CombineDictionariesClosure(Dictionary* master_dictionary) :
+_master_dictionary(master_dictionary) {}
+void do_cld(ClassLoaderData* cld) {
+ResourceMark rm;
+if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) {
+for (int i = 0; i < cld->dictionary()->table_size(); ++i) {
+Dictionary* curr_dictionary = cld->dictionary();
+DictionaryEntry* p = curr_dictionary->bucket(i);
+while (p != NULL) {
+Symbol* name = p->instance_klass()->name();
+unsigned int d_hash = _master_dictionary->compute_hash(name);
+int d_index = _master_dictionary->hash_to_index(d_hash);
+DictionaryEntry* next = p->next();
+if (p->literal()->class_loader_data() != cld) {
+// This is an initiating class loader entry; don't use it
+log_trace(cds)("Skipping initiating cl entry: %s", name->as_C_string());
+curr_dictionary->free_entry(p);
+} else {
+log_trace(cds)("Moved to boot dictionary: %s", name->as_C_string());
+curr_dictionary->unlink_entry(p);
+p->set_pd_set(NULL); // pd_set is runtime only information and will be reconstructed.
+_master_dictionary->add_entry(d_index, p);
+}
+p = next;
+}
+*curr_dictionary->bucket_addr(i) = NULL;
+}
+}
+}
+};
+// Combining platform and system loader dictionaries into boot loader dictionaries.
+// During run time, we only have one shared dictionary.
+void SystemDictionary::combine_shared_dictionaries() {
+assert(DumpSharedSpaces, "dump time only");
+Dictionary* master_dictionary = ClassLoaderData::the_null_class_loader_data()->dictionary();
+CombineDictionariesClosure cdc(master_dictionary);
+ClassLoaderDataGraph::cld_do(&cdc);
+// These tables are no longer valid or necessary. Keeping them around will
+// cause SystemDictionary::verify() to fail. Let's empty them.
+_placeholders        = new PlaceholderTable(_placeholder_table_size);
+_loader_constraints  = new LoaderConstraintTable(_loader_constraint_size);
+NOT_PRODUCT(SystemDictionary::verify());
+}
+// caller needs ResourceMark
+const char* SystemDictionary::loader_name(const oop loader) {
+return ((loader) == NULL ? "<bootloader>" :
+InstanceKlass::cast((loader)->klass())->name()->as_C_string());
+}
+// caller needs ResourceMark
+const char* SystemDictionary::loader_name(const ClassLoaderData* loader_data) {
+return (loader_data->class_loader() == NULL ? "<bootloader>" :
+SystemDictionary::loader_name(loader_data->class_loader()));
+}

changeset 47216	71c04702a3d5
parent 47103	a993ec29ec75
child 47614	0ecfd6c951a6