1 /*
   2  * Copyright (c) 1997, 2015, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "classfile/classLoaderData.inline.hpp"
  27 #include "classfile/dictionary.hpp"
  28 #include "classfile/javaClasses.inline.hpp"
  29 #include "classfile/loaderConstraints.hpp"
  30 #include "classfile/placeholders.hpp"
  31 #include "classfile/resolutionErrors.hpp"
  32 #include "classfile/stringTable.hpp"
  33 #include "classfile/systemDictionary.hpp"
  34 #include "classfile/vmSymbols.hpp"
  35 #include "code/codeCache.hpp"
  36 #include "compiler/compileBroker.hpp"
  37 #include "interpreter/bytecodeStream.hpp"
  38 #include "interpreter/interpreter.hpp"
  39 #include "memory/filemap.hpp"
  40 #include "memory/gcLocker.hpp"
  41 #include "memory/oopFactory.hpp"
  42 #include "oops/instanceKlass.hpp"
  43 #include "oops/instanceRefKlass.hpp"
  44 #include "oops/klass.inline.hpp"
  45 #include "oops/methodData.hpp"
  46 #include "oops/objArrayKlass.hpp"
  47 #include "oops/objArrayOop.inline.hpp"
  48 #include "oops/oop.inline.hpp"
  49 #include "oops/typeArrayKlass.hpp"
  50 #include "prims/jvmtiEnvBase.hpp"
  51 #include "prims/methodHandles.hpp"
  52 #include "runtime/arguments.hpp"
  53 #include "runtime/biasedLocking.hpp"
  54 #include "runtime/fieldType.hpp"
  55 #include "runtime/handles.inline.hpp"
  56 #include "runtime/java.hpp"
  57 #include "runtime/javaCalls.hpp"
  58 #include "runtime/mutexLocker.hpp"
  59 #include "runtime/orderAccess.inline.hpp"
  60 #include "runtime/signature.hpp"
  61 #include "services/classLoadingService.hpp"
  62 #include "services/threadService.hpp"
  63 #include "utilities/macros.hpp"
  64 #include "utilities/ticks.hpp"
  65 #if INCLUDE_CDS
  66 #include "classfile/sharedClassUtil.hpp"
  67 #include "classfile/systemDictionaryShared.hpp"
  68 #endif
  69 #if INCLUDE_TRACE
  70 #include "trace/tracing.hpp"
  71 #endif
  72 
  73 Dictionary*            SystemDictionary::_dictionary          = NULL;
  74 PlaceholderTable*      SystemDictionary::_placeholders        = NULL;
  75 Dictionary*            SystemDictionary::_shared_dictionary   = NULL;
  76 LoaderConstraintTable* SystemDictionary::_loader_constraints  = NULL;
  77 ResolutionErrorTable*  SystemDictionary::_resolution_errors   = NULL;
  78 SymbolPropertyTable*   SystemDictionary::_invoke_method_table = NULL;
  79 
  80 
  81 int         SystemDictionary::_number_of_modifications = 0;
  82 int         SystemDictionary::_sdgeneration               = 0;
  83 const int   SystemDictionary::_primelist[_prime_array_size] = {1009,2017,4049,5051,10103,
  84               20201,40423,99991};
  85 
  86 oop         SystemDictionary::_system_loader_lock_obj     =  NULL;
  87 
  88 Klass*      SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
  89                                                           =  { NULL /*, NULL...*/ };
  90 
  91 Klass*      SystemDictionary::_box_klasses[T_VOID+1]      =  { NULL /*, NULL...*/ };
  92 
  93 oop         SystemDictionary::_java_system_loader         =  NULL;
  94 
  95 bool        SystemDictionary::_has_loadClassInternal      =  false;
  96 bool        SystemDictionary::_has_checkPackageAccess     =  false;
  97 
  98 // lazily initialized klass variables
  99 Klass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
 100 
 101 
 102 // ----------------------------------------------------------------------------
 103 // Java-level SystemLoader
 104 
 105 oop SystemDictionary::java_system_loader() {
 106   return _java_system_loader;
 107 }
 108 
 109 void SystemDictionary::compute_java_system_loader(TRAPS) {
 110   KlassHandle system_klass(THREAD, WK_KLASS(ClassLoader_klass));
 111   JavaValue result(T_OBJECT);
 112   JavaCalls::call_static(&result,
 113                          KlassHandle(THREAD, WK_KLASS(ClassLoader_klass)),
 114                          vmSymbols::getSystemClassLoader_name(),
 115                          vmSymbols::void_classloader_signature(),
 116                          CHECK);
 117 
 118   _java_system_loader = (oop)result.get_jobject();
 119 
 120   CDS_ONLY(SystemDictionaryShared::initialize(CHECK);)
 121 }
 122 
 123 
 124 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, TRAPS) {
 125   if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
 126   return ClassLoaderDataGraph::find_or_create(class_loader, THREAD);
 127 }
 128 
 129 // ----------------------------------------------------------------------------
 130 // debugging
 131 
 132 #ifdef ASSERT
 133 
 134 // return true if class_name contains no '.' (internal format is '/')
 135 bool SystemDictionary::is_internal_format(Symbol* class_name) {
 136   if (class_name != NULL) {
 137     ResourceMark rm;
 138     char* name = class_name->as_C_string();
 139     return strchr(name, '.') == NULL;
 140   } else {
 141     return true;
 142   }
 143 }
 144 
 145 #endif
 146 
 147 // ----------------------------------------------------------------------------
 148 // Parallel class loading check
 149 
 150 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
 151   if (UnsyncloadClass || class_loader.is_null()) return true;
 152   if (AlwaysLockClassLoader) return false;
 153   return java_lang_ClassLoader::parallelCapable(class_loader());
 154 }
 155 // ----------------------------------------------------------------------------
 156 // ParallelDefineClass flag does not apply to bootclass loader
 157 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
 158    if (class_loader.is_null()) return false;
 159    if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
 160      return true;
 161    }
 162    return false;
 163 }
 164 
 165 /**
 166  * Returns true if the passed class loader is the extension class loader.
 167  */
 168 bool SystemDictionary::is_ext_class_loader(Handle class_loader) {
 169   if (class_loader.is_null()) {
 170     return false;
 171   }
 172   return (class_loader->klass()->name()->equals(vmSymbols::sun_misc_Launcher_ExtClassLoader()));
 173 }
 174 
 175 // ----------------------------------------------------------------------------
 176 // Resolving of classes
 177 
 178 // Forwards to resolve_or_null
 179 
 180 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
 181   Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
 182   if (HAS_PENDING_EXCEPTION || klass == NULL) {
 183     KlassHandle k_h(THREAD, klass);
 184     // can return a null klass
 185     klass = handle_resolution_exception(class_name, throw_error, k_h, THREAD);
 186   }
 187   return klass;
 188 }
 189 
 190 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name,
 191                                                      bool throw_error,
 192                                                      KlassHandle klass_h, TRAPS) {
 193   if (HAS_PENDING_EXCEPTION) {
 194     // If we have a pending exception we forward it to the caller, unless throw_error is true,
 195     // in which case we have to check whether the pending exception is a ClassNotFoundException,
 196     // and if so convert it to a NoClassDefFoundError
 197     // And chain the original ClassNotFoundException
 198     if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
 199       ResourceMark rm(THREAD);
 200       assert(klass_h() == NULL, "Should not have result with exception pending");
 201       Handle e(THREAD, PENDING_EXCEPTION);
 202       CLEAR_PENDING_EXCEPTION;
 203       THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
 204     } else {
 205       return NULL;
 206     }
 207   }
 208   // Class not found, throw appropriate error or exception depending on value of throw_error
 209   if (klass_h() == NULL) {
 210     ResourceMark rm(THREAD);
 211     if (throw_error) {
 212       THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
 213     } else {
 214       THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
 215     }
 216   }
 217   return (Klass*)klass_h();
 218 }
 219 
 220 
 221 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
 222                                            bool throw_error, TRAPS)
 223 {
 224   return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
 225 }
 226 
 227 
 228 // Forwards to resolve_instance_class_or_null
 229 
 230 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
 231   assert(!THREAD->is_Compiler_thread(),
 232          err_msg("can not load classes with compiler thread: class=%s, classloader=%s",
 233                  class_name->as_C_string(),
 234                  class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string()));
 235   if (FieldType::is_array(class_name)) {
 236     return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD);
 237   } else if (FieldType::is_obj(class_name)) {
 238     ResourceMark rm(THREAD);
 239     // Ignore wrapping L and ;.
 240     TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
 241                                    class_name->utf8_length() - 2, CHECK_NULL);
 242     return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD);
 243   } else {
 244     return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD);
 245   }
 246 }
 247 
 248 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
 249   return resolve_or_null(class_name, Handle(), Handle(), THREAD);
 250 }
 251 
 252 // Forwards to resolve_instance_class_or_null
 253 
 254 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
 255                                                        Handle class_loader,
 256                                                        Handle protection_domain,
 257                                                        TRAPS) {
 258   assert(FieldType::is_array(class_name), "must be array");
 259   Klass* k = NULL;
 260   FieldArrayInfo fd;
 261   // dimension and object_key in FieldArrayInfo are assigned as a side-effect
 262   // of this call
 263   BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
 264   if (t == T_OBJECT) {
 265     // naked oop "k" is OK here -- we assign back into it
 266     k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
 267                                                          class_loader,
 268                                                          protection_domain,
 269                                                          CHECK_NULL);
 270     if (k != NULL) {
 271       k = k->array_klass(fd.dimension(), CHECK_NULL);
 272     }
 273   } else {
 274     k = Universe::typeArrayKlassObj(t);
 275     k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
 276   }
 277   return k;
 278 }
 279 
 280 
 281 // Must be called for any super-class or super-interface resolution
 282 // during class definition to allow class circularity checking
 283 // super-interface callers:
 284 //    parse_interfaces - for defineClass & jvmtiRedefineClasses
 285 // super-class callers:
 286 //   ClassFileParser - for defineClass & jvmtiRedefineClasses
 287 //   load_shared_class - while loading a class from shared archive
 288 //   resolve_instance_class_or_null:
 289 //     via: handle_parallel_super_load
 290 //      when resolving a class that has an existing placeholder with
 291 //      a saved superclass [i.e. a defineClass is currently in progress]
 292 //      if another thread is trying to resolve the class, it must do
 293 //      super-class checks on its own thread to catch class circularity
 294 // This last call is critical in class circularity checking for cases
 295 // where classloading is delegated to different threads and the
 296 // classloader lock is released.
 297 // Take the case: Base->Super->Base
 298 //   1. If thread T1 tries to do a defineClass of class Base
 299 //    resolve_super_or_fail creates placeholder: T1, Base (super Super)
 300 //   2. resolve_instance_class_or_null does not find SD or placeholder for Super
 301 //    so it tries to load Super
 302 //   3. If we load the class internally, or user classloader uses same thread
 303 //      loadClassFromxxx or defineClass via parseClassFile Super ...
 304 //      3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
 305 //      3.3 resolve_instance_class_or_null Base, finds placeholder for Base
 306 //      3.4 calls resolve_super_or_fail Base
 307 //      3.5 finds T1,Base -> throws class circularity
 308 //OR 4. If T2 tries to resolve Super via defineClass Super ...
 309 //      4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
 310 //      4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
 311 //      4.3 calls resolve_super_or_fail Super in parallel on own thread T2
 312 //      4.4 finds T2, Super -> throws class circularity
 313 // Must be called, even if superclass is null, since this is
 314 // where the placeholder entry is created which claims this
 315 // thread is loading this class/classloader.
 316 Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
 317                                                  Symbol* class_name,
 318                                                  Handle class_loader,
 319                                                  Handle protection_domain,
 320                                                  bool is_superclass,
 321                                                  TRAPS) {
 322   // Double-check, if child class is already loaded, just return super-class,interface
 323   // Don't add a placedholder if already loaded, i.e. already in system dictionary
 324   // Make sure there's a placeholder for the *child* before resolving.
 325   // Used as a claim that this thread is currently loading superclass/classloader
 326   // Used here for ClassCircularity checks and also for heap verification
 327   // (every InstanceKlass in the heap needs to be in the system dictionary
 328   // or have a placeholder).
 329   // Must check ClassCircularity before checking if super class is already loaded
 330   //
 331   // We might not already have a placeholder if this child_name was
 332   // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
 333   // the name of the class might not be known until the stream is actually
 334   // parsed.
 335   // Bugs 4643874, 4715493
 336   // compute_hash can have a safepoint
 337 
 338   ClassLoaderData* loader_data = class_loader_data(class_loader);
 339   unsigned int d_hash = dictionary()->compute_hash(child_name, loader_data);
 340   int d_index = dictionary()->hash_to_index(d_hash);
 341   unsigned int p_hash = placeholders()->compute_hash(child_name, loader_data);
 342   int p_index = placeholders()->hash_to_index(p_hash);
 343   // can't throw error holding a lock
 344   bool child_already_loaded = false;
 345   bool throw_circularity_error = false;
 346   {
 347     MutexLocker mu(SystemDictionary_lock, THREAD);
 348     Klass* childk = find_class(d_index, d_hash, child_name, loader_data);
 349     Klass* quicksuperk;
 350     // to support // loading: if child done loading, just return superclass
 351     // if class_name, & class_loader don't match:
 352     // if initial define, SD update will give LinkageError
 353     // if redefine: compare_class_versions will give HIERARCHY_CHANGED
 354     // so we don't throw an exception here.
 355     // see: nsk redefclass014 & java.lang.instrument Instrument032
 356     if ((childk != NULL ) && (is_superclass) &&
 357        ((quicksuperk = InstanceKlass::cast(childk)->super()) != NULL) &&
 358 
 359          ((quicksuperk->name()->equals(class_name)) &&
 360             (quicksuperk->class_loader()  == class_loader()))) {
 361            return quicksuperk;
 362     } else {
 363       PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
 364       if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
 365           throw_circularity_error = true;
 366       }
 367     }
 368     if (!throw_circularity_error) {
 369       PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
 370     }
 371   }
 372   if (throw_circularity_error) {
 373       ResourceMark rm(THREAD);
 374       THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
 375   }
 376 
 377 // java.lang.Object should have been found above
 378   assert(class_name != NULL, "null super class for resolving");
 379   // Resolve the super class or interface, check results on return
 380   Klass* superk = SystemDictionary::resolve_or_null(class_name,
 381                                                  class_loader,
 382                                                  protection_domain,
 383                                                  THREAD);
 384 
 385   KlassHandle superk_h(THREAD, superk);
 386 
 387   // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
 388   // It is no longer necessary to keep the placeholder table alive until update_dictionary
 389   // or error. GC used to walk the placeholder table as strong roots.
 390   // The instanceKlass is kept alive because the class loader is on the stack,
 391   // which keeps the loader_data alive, as well as all instanceKlasses in
 392   // the loader_data. parseClassFile adds the instanceKlass to loader_data.
 393   {
 394     MutexLocker mu(SystemDictionary_lock, THREAD);
 395     placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
 396     SystemDictionary_lock->notify_all();
 397   }
 398   if (HAS_PENDING_EXCEPTION || superk_h() == NULL) {
 399     // can null superk
 400     superk_h = KlassHandle(THREAD, handle_resolution_exception(class_name, true, superk_h, THREAD));
 401   }
 402 
 403   return superk_h();
 404 }
 405 
 406 void SystemDictionary::validate_protection_domain(instanceKlassHandle klass,
 407                                                   Handle class_loader,
 408                                                   Handle protection_domain,
 409                                                   TRAPS) {
 410   if(!has_checkPackageAccess()) return;
 411 
 412   // Now we have to call back to java to check if the initating class has access
 413   JavaValue result(T_VOID);
 414   if (TraceProtectionDomainVerification) {
 415     // Print out trace information
 416     tty->print_cr("Checking package access");
 417     tty->print(" - class loader:      "); class_loader()->print_value_on(tty);      tty->cr();
 418     tty->print(" - protection domain: "); protection_domain()->print_value_on(tty); tty->cr();
 419     tty->print(" - loading:           "); klass()->print_value_on(tty);             tty->cr();
 420   }
 421 
 422   KlassHandle system_loader(THREAD, SystemDictionary::ClassLoader_klass());
 423   JavaCalls::call_special(&result,
 424                          class_loader,
 425                          system_loader,
 426                          vmSymbols::checkPackageAccess_name(),
 427                          vmSymbols::class_protectiondomain_signature(),
 428                          Handle(THREAD, klass->java_mirror()),
 429                          protection_domain,
 430                          THREAD);
 431 
 432   if (TraceProtectionDomainVerification) {
 433     if (HAS_PENDING_EXCEPTION) {
 434       tty->print_cr(" -> DENIED !!!!!!!!!!!!!!!!!!!!!");
 435     } else {
 436      tty->print_cr(" -> granted");
 437     }
 438     tty->cr();
 439   }
 440 
 441   if (HAS_PENDING_EXCEPTION) return;
 442 
 443   // If no exception has been thrown, we have validated the protection domain
 444   // Insert the protection domain of the initiating class into the set.
 445   {
 446     // We recalculate the entry here -- we've called out to java since
 447     // the last time it was calculated.
 448     ClassLoaderData* loader_data = class_loader_data(class_loader);
 449 
 450     Symbol*  kn = klass->name();
 451     unsigned int d_hash = dictionary()->compute_hash(kn, loader_data);
 452     int d_index = dictionary()->hash_to_index(d_hash);
 453 
 454     MutexLocker mu(SystemDictionary_lock, THREAD);
 455     {
 456       // Note that we have an entry, and entries can be deleted only during GC,
 457       // so we cannot allow GC to occur while we're holding this entry.
 458 
 459       // We're using a No_Safepoint_Verifier to catch any place where we
 460       // might potentially do a GC at all.
 461       // Dictionary::do_unloading() asserts that classes in SD are only
 462       // unloaded at a safepoint. Anonymous classes are not in SD.
 463       No_Safepoint_Verifier nosafepoint;
 464       dictionary()->add_protection_domain(d_index, d_hash, klass, loader_data,
 465                                           protection_domain, THREAD);
 466     }
 467   }
 468 }
 469 
 470 // We only get here if this thread finds that another thread
 471 // has already claimed the placeholder token for the current operation,
 472 // but that other thread either never owned or gave up the
 473 // object lock
 474 // Waits on SystemDictionary_lock to indicate placeholder table updated
 475 // On return, caller must recheck placeholder table state
 476 //
 477 // We only get here if
 478 //  1) custom classLoader, i.e. not bootstrap classloader
 479 //  2) UnsyncloadClass not set
 480 //  3) custom classLoader has broken the class loader objectLock
 481 //     so another thread got here in parallel
 482 //
 483 // lockObject must be held.
 484 // Complicated dance due to lock ordering:
 485 // Must first release the classloader object lock to
 486 // allow initial definer to complete the class definition
 487 // and to avoid deadlock
 488 // Reclaim classloader lock object with same original recursion count
 489 // Must release SystemDictionary_lock after notify, since
 490 // class loader lock must be claimed before SystemDictionary_lock
 491 // to prevent deadlocks
 492 //
 493 // The notify allows applications that did an untimed wait() on
 494 // the classloader object lock to not hang.
 495 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
 496   assert_lock_strong(SystemDictionary_lock);
 497 
 498   bool calledholdinglock
 499       = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
 500   assert(calledholdinglock,"must hold lock for notify");
 501   assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
 502   ObjectSynchronizer::notifyall(lockObject, THREAD);
 503   intptr_t recursions =  ObjectSynchronizer::complete_exit(lockObject, THREAD);
 504   SystemDictionary_lock->wait();
 505   SystemDictionary_lock->unlock();
 506   ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
 507   SystemDictionary_lock->lock();
 508 }
 509 
 510 // If the class in is in the placeholder table, class loading is in progress
 511 // For cases where the application changes threads to load classes, it
 512 // is critical to ClassCircularity detection that we try loading
 513 // the superclass on the same thread internally, so we do parallel
 514 // super class loading here.
 515 // This also is critical in cases where the original thread gets stalled
 516 // even in non-circularity situations.
 517 // Note: must call resolve_super_or_fail even if null super -
 518 // to force placeholder entry creation for this class for circularity detection
 519 // Caller must check for pending exception
 520 // Returns non-null Klass* if other thread has completed load
 521 // and we are done,
 522 // If return null Klass* and no pending exception, the caller must load the class
 523 instanceKlassHandle SystemDictionary::handle_parallel_super_load(
 524     Symbol* name, Symbol* superclassname, Handle class_loader,
 525     Handle protection_domain, Handle lockObject, TRAPS) {
 526 
 527   instanceKlassHandle nh = instanceKlassHandle(); // null Handle
 528   ClassLoaderData* loader_data = class_loader_data(class_loader);
 529   unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
 530   int d_index = dictionary()->hash_to_index(d_hash);
 531   unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
 532   int p_index = placeholders()->hash_to_index(p_hash);
 533 
 534   // superk is not used, resolve_super called for circularity check only
 535   // This code is reached in two situations. One if this thread
 536   // is loading the same class twice (e.g. ClassCircularity, or
 537   // java.lang.instrument).
 538   // The second is if another thread started the resolve_super first
 539   // and has not yet finished.
 540   // In both cases the original caller will clean up the placeholder
 541   // entry on error.
 542   Klass* superk = SystemDictionary::resolve_super_or_fail(name,
 543                                                           superclassname,
 544                                                           class_loader,
 545                                                           protection_domain,
 546                                                           true,
 547                                                           CHECK_(nh));
 548 
 549   // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
 550   // Serial class loaders and bootstrap classloader do wait for superclass loads
 551  if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
 552     MutexLocker mu(SystemDictionary_lock, THREAD);
 553     // Check if classloading completed while we were loading superclass or waiting
 554     Klass* check = find_class(d_index, d_hash, name, loader_data);
 555     if (check != NULL) {
 556       // Klass is already loaded, so just return it
 557       return(instanceKlassHandle(THREAD, check));
 558     } else {
 559       return nh;
 560     }
 561   }
 562 
 563   // must loop to both handle other placeholder updates
 564   // and spurious notifications
 565   bool super_load_in_progress = true;
 566   PlaceholderEntry* placeholder;
 567   while (super_load_in_progress) {
 568     MutexLocker mu(SystemDictionary_lock, THREAD);
 569     // Check if classloading completed while we were loading superclass or waiting
 570     Klass* check = find_class(d_index, d_hash, name, loader_data);
 571     if (check != NULL) {
 572       // Klass is already loaded, so just return it
 573       return(instanceKlassHandle(THREAD, check));
 574     } else {
 575       placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
 576       if (placeholder && placeholder->super_load_in_progress() ){
 577         // Before UnsyncloadClass:
 578         // We only get here if the application has released the
 579         // classloader lock when another thread was in the middle of loading a
 580         // superclass/superinterface for this class, and now
 581         // this thread is also trying to load this class.
 582         // To minimize surprises, the first thread that started to
 583         // load a class should be the one to complete the loading
 584         // with the classfile it initially expected.
 585         // This logic has the current thread wait once it has done
 586         // all the superclass/superinterface loading it can, until
 587         // the original thread completes the class loading or fails
 588         // If it completes we will use the resulting InstanceKlass
 589         // which we will find below in the systemDictionary.
 590         // We also get here for parallel bootstrap classloader
 591         if (class_loader.is_null()) {
 592           SystemDictionary_lock->wait();
 593         } else {
 594           double_lock_wait(lockObject, THREAD);
 595         }
 596       } else {
 597         // If not in SD and not in PH, other thread's load must have failed
 598         super_load_in_progress = false;
 599       }
 600     }
 601   }
 602   return (nh);
 603 }
 604 
 605 
 606 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
 607                                                         Handle class_loader,
 608                                                         Handle protection_domain,
 609                                                         TRAPS) {
 610   assert(name != NULL && !FieldType::is_array(name) &&
 611          !FieldType::is_obj(name), "invalid class name");
 612 
 613   Ticks class_load_start_time = Ticks::now();
 614 
 615   // Fix for 4474172; see evaluation for more details
 616   class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
 617   ClassLoaderData *loader_data = register_loader(class_loader, CHECK_NULL);
 618 
 619   // Do lookup to see if class already exist and the protection domain
 620   // has the right access
 621   // This call uses find which checks protection domain already matches
 622   // All subsequent calls use find_class, and set has_loaded_class so that
 623   // before we return a result we call out to java to check for valid protection domain
 624   // to allow returning the Klass* and add it to the pd_set if it is valid
 625   unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
 626   int d_index = dictionary()->hash_to_index(d_hash);
 627   Klass* probe = dictionary()->find(d_index, d_hash, name, loader_data,
 628                                       protection_domain, THREAD);
 629   if (probe != NULL) return probe;
 630 
 631 
 632   // Non-bootstrap class loaders will call out to class loader and
 633   // define via jvm/jni_DefineClass which will acquire the
 634   // class loader object lock to protect against multiple threads
 635   // defining the class in parallel by accident.
 636   // This lock must be acquired here so the waiter will find
 637   // any successful result in the SystemDictionary and not attempt
 638   // the define
 639   // ParallelCapable Classloaders and the bootstrap classloader,
 640   // or all classloaders with UnsyncloadClass do not acquire lock here
 641   bool DoObjectLock = true;
 642   if (is_parallelCapable(class_loader)) {
 643     DoObjectLock = false;
 644   }
 645 
 646   unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
 647   int p_index = placeholders()->hash_to_index(p_hash);
 648 
 649   // Class is not in SystemDictionary so we have to do loading.
 650   // Make sure we are synchronized on the class loader before we proceed
 651   Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
 652   check_loader_lock_contention(lockObject, THREAD);
 653   ObjectLocker ol(lockObject, THREAD, DoObjectLock);
 654 
 655   // Check again (after locking) if class already exist in SystemDictionary
 656   bool class_has_been_loaded   = false;
 657   bool super_load_in_progress  = false;
 658   bool havesupername = false;
 659   instanceKlassHandle k;
 660   PlaceholderEntry* placeholder;
 661   Symbol* superclassname = NULL;
 662 
 663   {
 664     MutexLocker mu(SystemDictionary_lock, THREAD);
 665     Klass* check = find_class(d_index, d_hash, name, loader_data);
 666     if (check != NULL) {
 667       // Klass is already loaded, so just return it
 668       class_has_been_loaded = true;
 669       k = instanceKlassHandle(THREAD, check);
 670     } else {
 671       placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
 672       if (placeholder && placeholder->super_load_in_progress()) {
 673          super_load_in_progress = true;
 674          if (placeholder->havesupername() == true) {
 675            superclassname = placeholder->supername();
 676            havesupername = true;
 677          }
 678       }
 679     }
 680   }
 681 
 682   // If the class is in the placeholder table, class loading is in progress
 683   if (super_load_in_progress && havesupername==true) {
 684     k = SystemDictionary::handle_parallel_super_load(name, superclassname,
 685         class_loader, protection_domain, lockObject, THREAD);
 686     if (HAS_PENDING_EXCEPTION) {
 687       return NULL;
 688     }
 689     if (!k.is_null()) {
 690       class_has_been_loaded = true;
 691     }
 692   }
 693 
 694   bool throw_circularity_error = false;
 695   if (!class_has_been_loaded) {
 696     bool load_instance_added = false;
 697 
 698     // add placeholder entry to record loading instance class
 699     // Five cases:
 700     // All cases need to prevent modifying bootclasssearchpath
 701     // in parallel with a classload of same classname
 702     // Redefineclasses uses existence of the placeholder for the duration
 703     // of the class load to prevent concurrent redefinition of not completely
 704     // defined classes.
 705     // case 1. traditional classloaders that rely on the classloader object lock
 706     //   - no other need for LOAD_INSTANCE
 707     // case 2. traditional classloaders that break the classloader object lock
 708     //    as a deadlock workaround. Detection of this case requires that
 709     //    this check is done while holding the classloader object lock,
 710     //    and that lock is still held when calling classloader's loadClass.
 711     //    For these classloaders, we ensure that the first requestor
 712     //    completes the load and other requestors wait for completion.
 713     // case 3. UnsyncloadClass - don't use objectLocker
 714     //    With this flag, we allow parallel classloading of a
 715     //    class/classloader pair
 716     // case4. Bootstrap classloader - don't own objectLocker
 717     //    This classloader supports parallelism at the classloader level,
 718     //    but only allows a single load of a class/classloader pair.
 719     //    No performance benefit and no deadlock issues.
 720     // case 5. parallelCapable user level classloaders - without objectLocker
 721     //    Allow parallel classloading of a class/classloader pair
 722 
 723     {
 724       MutexLocker mu(SystemDictionary_lock, THREAD);
 725       if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
 726         PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
 727         if (oldprobe) {
 728           // only need check_seen_thread once, not on each loop
 729           // 6341374 java/lang/Instrument with -Xcomp
 730           if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
 731             throw_circularity_error = true;
 732           } else {
 733             // case 1: traditional: should never see load_in_progress.
 734             while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
 735 
 736               // case 4: bootstrap classloader: prevent futile classloading,
 737               // wait on first requestor
 738               if (class_loader.is_null()) {
 739                 SystemDictionary_lock->wait();
 740               } else {
 741               // case 2: traditional with broken classloader lock. wait on first
 742               // requestor.
 743                 double_lock_wait(lockObject, THREAD);
 744               }
 745               // Check if classloading completed while we were waiting
 746               Klass* check = find_class(d_index, d_hash, name, loader_data);
 747               if (check != NULL) {
 748                 // Klass is already loaded, so just return it
 749                 k = instanceKlassHandle(THREAD, check);
 750                 class_has_been_loaded = true;
 751               }
 752               // check if other thread failed to load and cleaned up
 753               oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
 754             }
 755           }
 756         }
 757       }
 758       // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
 759       // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try
 760       // LOAD_INSTANCE in parallel
 761 
 762       if (!throw_circularity_error && !class_has_been_loaded) {
 763         PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
 764         load_instance_added = true;
 765         // For class loaders that do not acquire the classloader object lock,
 766         // if they did not catch another thread holding LOAD_INSTANCE,
 767         // need a check analogous to the acquire ObjectLocker/find_class
 768         // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
 769         // one final check if the load has already completed
 770         // class loaders holding the ObjectLock shouldn't find the class here
 771         Klass* check = find_class(d_index, d_hash, name, loader_data);
 772         if (check != NULL) {
 773         // Klass is already loaded, so return it after checking/adding protection domain
 774           k = instanceKlassHandle(THREAD, check);
 775           class_has_been_loaded = true;
 776         }
 777       }
 778     }
 779 
 780     // must throw error outside of owning lock
 781     if (throw_circularity_error) {
 782       assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
 783       ResourceMark rm(THREAD);
 784       THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
 785     }
 786 
 787     if (!class_has_been_loaded) {
 788 
 789       // Do actual loading
 790       k = load_instance_class(name, class_loader, THREAD);
 791 
 792       // For UnsyncloadClass only
 793       // If they got a linkageError, check if a parallel class load succeeded.
 794       // If it did, then for bytecode resolution the specification requires
 795       // that we return the same result we did for the other thread, i.e. the
 796       // successfully loaded InstanceKlass
 797       // Should not get here for classloaders that support parallelism
 798       // with the new cleaner mechanism, even with AllowParallelDefineClass
 799       // Bootstrap goes through here to allow for an extra guarantee check
 800       if (UnsyncloadClass || (class_loader.is_null())) {
 801         if (k.is_null() && HAS_PENDING_EXCEPTION
 802           && PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass())) {
 803           MutexLocker mu(SystemDictionary_lock, THREAD);
 804           Klass* check = find_class(d_index, d_hash, name, loader_data);
 805           if (check != NULL) {
 806             // Klass is already loaded, so just use it
 807             k = instanceKlassHandle(THREAD, check);
 808             CLEAR_PENDING_EXCEPTION;
 809             guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?");
 810           }
 811         }
 812       }
 813 
 814       // If everything was OK (no exceptions, no null return value), and
 815       // class_loader is NOT the defining loader, do a little more bookkeeping.
 816       if (!HAS_PENDING_EXCEPTION && !k.is_null() &&
 817         k->class_loader() != class_loader()) {
 818 
 819         check_constraints(d_index, d_hash, k, class_loader, false, THREAD);
 820 
 821         // Need to check for a PENDING_EXCEPTION again; check_constraints
 822         // can throw and doesn't use the CHECK macro.
 823         if (!HAS_PENDING_EXCEPTION) {
 824           { // Grabbing the Compile_lock prevents systemDictionary updates
 825             // during compilations.
 826             MutexLocker mu(Compile_lock, THREAD);
 827             update_dictionary(d_index, d_hash, p_index, p_hash,
 828                               k, class_loader, THREAD);
 829           }
 830 
 831           if (JvmtiExport::should_post_class_load()) {
 832             Thread *thread = THREAD;
 833             assert(thread->is_Java_thread(), "thread->is_Java_thread()");
 834             JvmtiExport::post_class_load((JavaThread *) thread, k());
 835           }
 836         }
 837       }
 838     } // load_instance_class loop
 839 
 840     if (load_instance_added == true) {
 841       // clean up placeholder entries for LOAD_INSTANCE success or error
 842       // This brackets the SystemDictionary updates for both defining
 843       // and initiating loaders
 844       MutexLocker mu(SystemDictionary_lock, THREAD);
 845       placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
 846       SystemDictionary_lock->notify_all();
 847     }
 848   }
 849 
 850   if (HAS_PENDING_EXCEPTION || k.is_null()) {
 851     return NULL;
 852   }
 853 
 854   post_class_load_event(class_load_start_time, k, class_loader);
 855 
 856 #ifdef ASSERT
 857   {
 858     ClassLoaderData* loader_data = k->class_loader_data();
 859     MutexLocker mu(SystemDictionary_lock, THREAD);
 860     Klass* kk = find_class(name, loader_data);
 861     assert(kk == k(), "should be present in dictionary");
 862   }
 863 #endif
 864 
 865   // return if the protection domain in NULL
 866   if (protection_domain() == NULL) return k();
 867 
 868   // Check the protection domain has the right access
 869   {
 870     MutexLocker mu(SystemDictionary_lock, THREAD);
 871     // Note that we have an entry, and entries can be deleted only during GC,
 872     // so we cannot allow GC to occur while we're holding this entry.
 873     // We're using a No_Safepoint_Verifier to catch any place where we
 874     // might potentially do a GC at all.
 875     // Dictionary::do_unloading() asserts that classes in SD are only
 876     // unloaded at a safepoint. Anonymous classes are not in SD.
 877     No_Safepoint_Verifier nosafepoint;
 878     if (dictionary()->is_valid_protection_domain(d_index, d_hash, name,
 879                                                  loader_data,
 880                                                  protection_domain)) {
 881       return k();
 882     }
 883   }
 884 
 885   // Verify protection domain. If it fails an exception is thrown
 886   validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
 887 
 888   return k();
 889 }
 890 
 891 
 892 // This routine does not lock the system dictionary.
 893 //
 894 // Since readers don't hold a lock, we must make sure that system
 895 // dictionary entries are only removed at a safepoint (when only one
 896 // thread is running), and are added to in a safe way (all links must
 897 // be updated in an MT-safe manner).
 898 //
 899 // Callers should be aware that an entry could be added just after
 900 // _dictionary->bucket(index) is read here, so the caller will not see
 901 // the new entry.
 902 
 903 Klass* SystemDictionary::find(Symbol* class_name,
 904                               Handle class_loader,
 905                               Handle protection_domain,
 906                               TRAPS) {
 907 
 908   // The result of this call should be consistent with the result
 909   // of the call to resolve_instance_class_or_null().
 910   // See evaluation 6790209 and 4474172 for more details.
 911   class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
 912   ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
 913 
 914   if (loader_data == NULL) {
 915     // If the ClassLoaderData has not been setup,
 916     // then the class loader has no entries in the dictionary.
 917     return NULL;
 918   }
 919 
 920   unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
 921   int d_index = dictionary()->hash_to_index(d_hash);
 922 
 923   {
 924     // Note that we have an entry, and entries can be deleted only during GC,
 925     // so we cannot allow GC to occur while we're holding this entry.
 926     // We're using a No_Safepoint_Verifier to catch any place where we
 927     // might potentially do a GC at all.
 928     // Dictionary::do_unloading() asserts that classes in SD are only
 929     // unloaded at a safepoint. Anonymous classes are not in SD.
 930     No_Safepoint_Verifier nosafepoint;
 931     return dictionary()->find(d_index, d_hash, class_name, loader_data,
 932                               protection_domain, THREAD);
 933   }
 934 }
 935 
 936 
 937 // Look for a loaded instance or array klass by name.  Do not do any loading.
 938 // return NULL in case of error.
 939 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
 940                                                       Handle class_loader,
 941                                                       Handle protection_domain,
 942                                                       TRAPS) {
 943   Klass* k = NULL;
 944   assert(class_name != NULL, "class name must be non NULL");
 945 
 946   if (FieldType::is_array(class_name)) {
 947     // The name refers to an array.  Parse the name.
 948     // dimension and object_key in FieldArrayInfo are assigned as a
 949     // side-effect of this call
 950     FieldArrayInfo fd;
 951     BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
 952     if (t != T_OBJECT) {
 953       k = Universe::typeArrayKlassObj(t);
 954     } else {
 955       k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
 956     }
 957     if (k != NULL) {
 958       k = k->array_klass_or_null(fd.dimension());
 959     }
 960   } else {
 961     k = find(class_name, class_loader, protection_domain, THREAD);
 962   }
 963   return k;
 964 }
 965 
 966 // Note: this method is much like resolve_from_stream, but
 967 // updates no supplemental data structures.
 968 // TODO consolidate the two methods with a helper routine?
 969 Klass* SystemDictionary::parse_stream(Symbol* class_name,
 970                                       Handle class_loader,
 971                                       Handle protection_domain,
 972                                       ClassFileStream* st,
 973                                       KlassHandle host_klass,
 974                                       GrowableArray<Handle>* cp_patches,
 975                                       TRAPS) {
 976   TempNewSymbol parsed_name = NULL;
 977 
 978   Ticks class_load_start_time = Ticks::now();
 979 
 980   ClassLoaderData* loader_data;
 981   if (host_klass.not_null()) {
 982     // Create a new CLD for anonymous class, that uses the same class loader
 983     // as the host_klass
 984     guarantee(host_klass->class_loader() == class_loader(), "should be the same");
 985     guarantee(!DumpSharedSpaces, "must not create anonymous classes when dumping");
 986     loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader(), CHECK_NULL);
 987     loader_data->record_dependency(host_klass(), CHECK_NULL);
 988   } else {
 989     loader_data = ClassLoaderData::class_loader_data(class_loader());
 990   }
 991 
 992   // Parse the stream. Note that we do this even though this klass might
 993   // already be present in the SystemDictionary, otherwise we would not
 994   // throw potential ClassFormatErrors.
 995   //
 996   // Note: "name" is updated.
 997 
 998   instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
 999                                                              loader_data,
1000                                                              protection_domain,
1001                                                              host_klass,
1002                                                              cp_patches,
1003                                                              parsed_name,
1004                                                              true,
1005                                                              THREAD);
1006 
1007 
1008   if (host_klass.not_null() && k.not_null()) {
1009     // If it's anonymous, initialize it now, since nobody else will.
1010 
1011     {
1012       MutexLocker mu_r(Compile_lock, THREAD);
1013 
1014       // Add to class hierarchy, initialize vtables, and do possible
1015       // deoptimizations.
1016       add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1017 
1018       // But, do not add to system dictionary.
1019 
1020       // compiled code dependencies need to be validated anyway
1021       notice_modification();
1022     }
1023 
1024     // Rewrite and patch constant pool here.
1025     k->link_class(CHECK_NULL);
1026     if (cp_patches != NULL) {
1027       k->constants()->patch_resolved_references(cp_patches);
1028     }
1029     k->eager_initialize(CHECK_NULL);
1030 
1031     // notify jvmti
1032     if (JvmtiExport::should_post_class_load()) {
1033         assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1034         JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1035     }
1036 
1037     post_class_load_event(class_load_start_time, k, class_loader);
1038   }
1039   assert(host_klass.not_null() || cp_patches == NULL,
1040          "cp_patches only found with host_klass");
1041 
1042   return k();
1043 }
1044 
1045 // Add a klass to the system from a stream (called by jni_DefineClass and
1046 // JVM_DefineClass).
1047 // Note: class_name can be NULL. In that case we do not know the name of
1048 // the class until we have parsed the stream.
1049 
1050 Klass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1051                                              Handle class_loader,
1052                                              Handle protection_domain,
1053                                              ClassFileStream* st,
1054                                              bool verify,
1055                                              TRAPS) {
1056 
1057   // Classloaders that support parallelism, e.g. bootstrap classloader,
1058   // or all classloaders with UnsyncloadClass do not acquire lock here
1059   bool DoObjectLock = true;
1060   if (is_parallelCapable(class_loader)) {
1061     DoObjectLock = false;
1062   }
1063 
1064   ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL);
1065 
1066   // Make sure we are synchronized on the class loader before we proceed
1067   Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1068   check_loader_lock_contention(lockObject, THREAD);
1069   ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1070 
1071   TempNewSymbol parsed_name = NULL;
1072 
1073   // Parse the stream. Note that we do this even though this klass might
1074   // already be present in the SystemDictionary, otherwise we would not
1075   // throw potential ClassFormatErrors.
1076   //
1077   // Note: "name" is updated.
1078 
1079   instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
1080                                                              loader_data,
1081                                                              protection_domain,
1082                                                              parsed_name,
1083                                                              verify,
1084                                                              THREAD);
1085 
1086   const char* pkg = "java/";
1087   if (!HAS_PENDING_EXCEPTION &&
1088       !class_loader.is_null() &&
1089       parsed_name != NULL &&
1090       !strncmp((const char*)parsed_name->bytes(), pkg, strlen(pkg))) {
1091     // It is illegal to define classes in the "java." package from
1092     // JVM_DefineClass or jni_DefineClass unless you're the bootclassloader
1093     ResourceMark rm(THREAD);
1094     char* name = parsed_name->as_C_string();
1095     char* index = strrchr(name, '/');
1096     *index = '\0'; // chop to just the package name
1097     while ((index = strchr(name, '/')) != NULL) {
1098       *index = '.'; // replace '/' with '.' in package name
1099     }
1100     const char* fmt = "Prohibited package name: %s";
1101     size_t len = strlen(fmt) + strlen(name);
1102     char* message = NEW_RESOURCE_ARRAY(char, len);
1103     jio_snprintf(message, len, fmt, name);
1104     Exceptions::_throw_msg(THREAD_AND_LOCATION,
1105       vmSymbols::java_lang_SecurityException(), message);
1106   }
1107 
1108   if (!HAS_PENDING_EXCEPTION) {
1109     assert(parsed_name->not_equals(NULL), "Sanity");
1110     assert(class_name == NULL || class_name->equals(parsed_name), "name mismatch");
1111     // Verification prevents us from creating names with dots in them, this
1112     // asserts that that's the case.
1113     assert(is_internal_format(parsed_name),
1114            "external class name format used internally");
1115 
1116     // Add class just loaded
1117     // If a class loader supports parallel classloading handle parallel define requests
1118     // find_or_define_instance_class may return a different InstanceKlass
1119     if (is_parallelCapable(class_loader)) {
1120       k = find_or_define_instance_class(class_name, class_loader, k, THREAD);
1121     } else {
1122       define_instance_class(k, THREAD);
1123     }
1124   }
1125 
1126   // Make sure we have an entry in the SystemDictionary on success
1127   debug_only( {
1128     if (!HAS_PENDING_EXCEPTION) {
1129       assert(parsed_name != NULL, "parsed_name is still null?");
1130       Symbol*  h_name = k->name();
1131       ClassLoaderData *defining_loader_data = k->class_loader_data();
1132 
1133       MutexLocker mu(SystemDictionary_lock, THREAD);
1134 
1135       Klass* check = find_class(parsed_name, loader_data);
1136       assert(check == k(), "should be present in the dictionary");
1137 
1138       Klass* check2 = find_class(h_name, defining_loader_data);
1139       assert(check == check2, "name inconsistancy in SystemDictionary");
1140     }
1141   } );
1142 
1143   return k();
1144 }
1145 
1146 #if INCLUDE_CDS
1147 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1148                                              int number_of_entries) {
1149   assert(length == _nof_buckets * sizeof(HashtableBucket<mtClass>),
1150          "bad shared dictionary size.");
1151   _shared_dictionary = new Dictionary(_nof_buckets, t, number_of_entries);
1152 }
1153 
1154 
1155 // If there is a shared dictionary, then find the entry for the
1156 // given shared system class, if any.
1157 
1158 Klass* SystemDictionary::find_shared_class(Symbol* class_name) {
1159   if (shared_dictionary() != NULL) {
1160     unsigned int d_hash = shared_dictionary()->compute_hash(class_name, NULL);
1161     int d_index = shared_dictionary()->hash_to_index(d_hash);
1162 
1163     return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1164   } else {
1165     return NULL;
1166   }
1167 }
1168 
1169 
1170 // Load a class from the shared spaces (found through the shared system
1171 // dictionary).  Force the superclass and all interfaces to be loaded.
1172 // Update the class definition to include sibling classes and no
1173 // subclasses (yet).  [Classes in the shared space are not part of the
1174 // object hierarchy until loaded.]
1175 
1176 instanceKlassHandle SystemDictionary::load_shared_class(
1177                  Symbol* class_name, Handle class_loader, TRAPS) {
1178   instanceKlassHandle ik (THREAD, find_shared_class(class_name));
1179   // Make sure we only return the boot class for the NULL classloader.
1180   if (ik.not_null() &&
1181       SharedClassUtil::is_shared_boot_class(ik()) && class_loader.is_null()) {
1182     Handle protection_domain;
1183     return load_shared_class(ik, class_loader, protection_domain, THREAD);
1184   }
1185   return instanceKlassHandle();
1186 }
1187 
1188 instanceKlassHandle SystemDictionary::load_shared_class(instanceKlassHandle ik,
1189                                                         Handle class_loader,
1190                                                         Handle protection_domain, TRAPS) {
1191   if (ik.not_null()) {
1192     instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1193     Symbol* class_name = ik->name();
1194 
1195     // Found the class, now load the superclass and interfaces.  If they
1196     // are shared, add them to the main system dictionary and reset
1197     // their hierarchy references (supers, subs, and interfaces).
1198 
1199     if (ik->super() != NULL) {
1200       Symbol*  cn = ik->super()->name();
1201       resolve_super_or_fail(class_name, cn,
1202                             class_loader, protection_domain, true, CHECK_(nh));
1203     }
1204 
1205     Array<Klass*>* interfaces = ik->local_interfaces();
1206     int num_interfaces = interfaces->length();
1207     for (int index = 0; index < num_interfaces; index++) {
1208       Klass* k = interfaces->at(index);
1209 
1210       // Note: can not use InstanceKlass::cast here because
1211       // interfaces' InstanceKlass's C++ vtbls haven't been
1212       // reinitialized yet (they will be once the interface classes
1213       // are loaded)
1214       Symbol* name = k->name();
1215       resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_(nh));
1216     }
1217 
1218     // Adjust methods to recover missing data.  They need addresses for
1219     // interpreter entry points and their default native method address
1220     // must be reset.
1221 
1222     // Updating methods must be done under a lock so multiple
1223     // threads don't update these in parallel
1224     //
1225     // Shared classes are all currently loaded by either the bootstrap or
1226     // internal parallel class loaders, so this will never cause a deadlock
1227     // on a custom class loader lock.
1228 
1229     ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1230     {
1231       Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1232       check_loader_lock_contention(lockObject, THREAD);
1233       ObjectLocker ol(lockObject, THREAD, true);
1234       ik->restore_unshareable_info(loader_data, protection_domain, CHECK_(nh));
1235     }
1236 
1237     if (TraceClassLoading) {
1238       ResourceMark rm;
1239       tty->print("[Loaded %s", ik->external_name());
1240       tty->print(" from shared objects file");
1241       if (class_loader.not_null()) {
1242         tty->print(" by %s", loader_data->loader_name());
1243       }
1244       tty->print_cr("]");
1245     }
1246 
1247     if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1248       // Only dump the classes that can be stored into CDS archive
1249       if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1250         ResourceMark rm(THREAD);
1251         classlist_file->print_cr("%s", ik->name()->as_C_string());
1252         classlist_file->flush();
1253       }
1254     }
1255 
1256     // notify a class loaded from shared object
1257     ClassLoadingService::notify_class_loaded(InstanceKlass::cast(ik()),
1258                                              true /* shared class */);
1259   }
1260   return ik;
1261 }
1262 #endif // INCLUDE_CDS
1263 
1264 instanceKlassHandle SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1265   instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1266   if (class_loader.is_null()) {
1267 
1268     // Search the shared system dictionary for classes preloaded into the
1269     // shared spaces.
1270     instanceKlassHandle k;
1271     {
1272 #if INCLUDE_CDS
1273       PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1274       k = load_shared_class(class_name, class_loader, THREAD);
1275 #endif
1276     }
1277 
1278     if (k.is_null()) {
1279       // Use VM class loader
1280       PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1281       k = ClassLoader::load_classfile(class_name, CHECK_(nh));
1282     }
1283 
1284     // find_or_define_instance_class may return a different InstanceKlass
1285     if (!k.is_null()) {
1286       k = find_or_define_instance_class(class_name, class_loader, k, CHECK_(nh));
1287     }
1288     return k;
1289   } else {
1290     // Use user specified class loader to load class. Call loadClass operation on class_loader.
1291     ResourceMark rm(THREAD);
1292 
1293     assert(THREAD->is_Java_thread(), "must be a JavaThread");
1294     JavaThread* jt = (JavaThread*) THREAD;
1295 
1296     PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1297                                ClassLoader::perf_app_classload_selftime(),
1298                                ClassLoader::perf_app_classload_count(),
1299                                jt->get_thread_stat()->perf_recursion_counts_addr(),
1300                                jt->get_thread_stat()->perf_timers_addr(),
1301                                PerfClassTraceTime::CLASS_LOAD);
1302 
1303     Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nh));
1304     // Translate to external class name format, i.e., convert '/' chars to '.'
1305     Handle string = java_lang_String::externalize_classname(s, CHECK_(nh));
1306 
1307     JavaValue result(T_OBJECT);
1308 
1309     KlassHandle spec_klass (THREAD, SystemDictionary::ClassLoader_klass());
1310 
1311     // Call public unsynchronized loadClass(String) directly for all class loaders
1312     // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will
1313     // acquire a class-name based lock rather than the class loader object lock.
1314     // JDK < 7 already acquire the class loader lock in loadClass(String, boolean),
1315     // so the call to loadClassInternal() was not required.
1316     //
1317     // UnsyncloadClass flag means both call loadClass(String) and do
1318     // not acquire the class loader lock even for class loaders that are
1319     // not parallelCapable. This was a risky transitional
1320     // flag for diagnostic purposes only. It is risky to call
1321     // custom class loaders without synchronization.
1322     // WARNING If a custom class loader does NOT synchronizer findClass, or callers of
1323     // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field.
1324     // Do NOT assume this will be supported in future releases.
1325     //
1326     // Added MustCallLoadClassInternal in case we discover in the field
1327     // a customer that counts on this call
1328     if (MustCallLoadClassInternal && has_loadClassInternal()) {
1329       JavaCalls::call_special(&result,
1330                               class_loader,
1331                               spec_klass,
1332                               vmSymbols::loadClassInternal_name(),
1333                               vmSymbols::string_class_signature(),
1334                               string,
1335                               CHECK_(nh));
1336     } else {
1337       JavaCalls::call_virtual(&result,
1338                               class_loader,
1339                               spec_klass,
1340                               vmSymbols::loadClass_name(),
1341                               vmSymbols::string_class_signature(),
1342                               string,
1343                               CHECK_(nh));
1344     }
1345 
1346     assert(result.get_type() == T_OBJECT, "just checking");
1347     oop obj = (oop) result.get_jobject();
1348 
1349     // Primitive classes return null since forName() can not be
1350     // used to obtain any of the Class objects representing primitives or void
1351     if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1352       instanceKlassHandle k =
1353                 instanceKlassHandle(THREAD, java_lang_Class::as_Klass(obj));
1354       // For user defined Java class loaders, check that the name returned is
1355       // the same as that requested.  This check is done for the bootstrap
1356       // loader when parsing the class file.
1357       if (class_name->equals(k->name())) {
1358         return k;
1359       }
1360     }
1361     // Class is not found or has the wrong name, return NULL
1362     return nh;
1363   }
1364 }
1365 
1366 void SystemDictionary::define_instance_class(instanceKlassHandle k, TRAPS) {
1367 
1368   ClassLoaderData* loader_data = k->class_loader_data();
1369   Handle class_loader_h(THREAD, loader_data->class_loader());
1370 
1371  // for bootstrap and other parallel classloaders don't acquire lock,
1372  // use placeholder token
1373  // If a parallelCapable class loader calls define_instance_class instead of
1374  // find_or_define_instance_class to get here, we have a timing
1375  // hole with systemDictionary updates and check_constraints
1376  if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1377     assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1378          compute_loader_lock_object(class_loader_h, THREAD)),
1379          "define called without lock");
1380   }
1381 
1382   // Check class-loading constraints. Throw exception if violation is detected.
1383   // Grabs and releases SystemDictionary_lock
1384   // The check_constraints/find_class call and update_dictionary sequence
1385   // must be "atomic" for a specific class/classloader pair so we never
1386   // define two different instanceKlasses for that class/classloader pair.
1387   // Existing classloaders will call define_instance_class with the
1388   // classloader lock held
1389   // Parallel classloaders will call find_or_define_instance_class
1390   // which will require a token to perform the define class
1391   Symbol* name_h = k->name();
1392   unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
1393   int d_index = dictionary()->hash_to_index(d_hash);
1394   check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK);
1395 
1396   // Register class just loaded with class loader (placed in Vector)
1397   // Note we do this before updating the dictionary, as this can
1398   // fail with an OutOfMemoryError (if it does, we will *not* put this
1399   // class in the dictionary and will not update the class hierarchy).
1400   // JVMTI FollowReferences needs to find the classes this way.
1401   if (k->class_loader() != NULL) {
1402     methodHandle m(THREAD, Universe::loader_addClass_method());
1403     JavaValue result(T_VOID);
1404     JavaCallArguments args(class_loader_h);
1405     args.push_oop(Handle(THREAD, k->java_mirror()));
1406     JavaCalls::call(&result, m, &args, CHECK);
1407   }
1408 
1409   // Add the new class. We need recompile lock during update of CHA.
1410   {
1411     unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
1412     int p_index = placeholders()->hash_to_index(p_hash);
1413 
1414     MutexLocker mu_r(Compile_lock, THREAD);
1415 
1416     // Add to class hierarchy, initialize vtables, and do possible
1417     // deoptimizations.
1418     add_to_hierarchy(k, CHECK); // No exception, but can block
1419 
1420     // Add to systemDictionary - so other classes can see it.
1421     // Grabs and releases SystemDictionary_lock
1422     update_dictionary(d_index, d_hash, p_index, p_hash,
1423                       k, class_loader_h, THREAD);
1424   }
1425   k->eager_initialize(THREAD);
1426 
1427   // notify jvmti
1428   if (JvmtiExport::should_post_class_load()) {
1429       assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1430       JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1431 
1432   }
1433 
1434 }
1435 
1436 // Support parallel classloading
1437 // All parallel class loaders, including bootstrap classloader
1438 // lock a placeholder entry for this class/class_loader pair
1439 // to allow parallel defines of different classes for this class loader
1440 // With AllowParallelDefine flag==true, in case they do not synchronize around
1441 // FindLoadedClass/DefineClass, calls, we check for parallel
1442 // loading for them, wait if a defineClass is in progress
1443 // and return the initial requestor's results
1444 // This flag does not apply to the bootstrap classloader.
1445 // With AllowParallelDefine flag==false, call through to define_instance_class
1446 // which will throw LinkageError: duplicate class definition.
1447 // False is the requested default.
1448 // For better performance, the class loaders should synchronize
1449 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1450 // potentially waste time reading and parsing the bytestream.
1451 // Note: VM callers should ensure consistency of k/class_name,class_loader
1452 instanceKlassHandle SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader, instanceKlassHandle k, TRAPS) {
1453 
1454   instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1455   Symbol*  name_h = k->name(); // passed in class_name may be null
1456   ClassLoaderData* loader_data = class_loader_data(class_loader);
1457 
1458   unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
1459   int d_index = dictionary()->hash_to_index(d_hash);
1460 
1461 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1462   unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
1463   int p_index = placeholders()->hash_to_index(p_hash);
1464   PlaceholderEntry* probe;
1465 
1466   {
1467     MutexLocker mu(SystemDictionary_lock, THREAD);
1468     // First check if class already defined
1469     if (UnsyncloadClass || (is_parallelDefine(class_loader))) {
1470       Klass* check = find_class(d_index, d_hash, name_h, loader_data);
1471       if (check != NULL) {
1472         return(instanceKlassHandle(THREAD, check));
1473       }
1474     }
1475 
1476     // Acquire define token for this class/classloader
1477     probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1478     // Wait if another thread defining in parallel
1479     // All threads wait - even those that will throw duplicate class: otherwise
1480     // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1481     // if other thread has not finished updating dictionary
1482     while (probe->definer() != NULL) {
1483       SystemDictionary_lock->wait();
1484     }
1485     // Only special cases allow parallel defines and can use other thread's results
1486     // Other cases fall through, and may run into duplicate defines
1487     // caught by finding an entry in the SystemDictionary
1488     if ((UnsyncloadClass || is_parallelDefine(class_loader)) && (probe->instance_klass() != NULL)) {
1489         placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1490         SystemDictionary_lock->notify_all();
1491 #ifdef ASSERT
1492         Klass* check = find_class(d_index, d_hash, name_h, loader_data);
1493         assert(check != NULL, "definer missed recording success");
1494 #endif
1495         return(instanceKlassHandle(THREAD, probe->instance_klass()));
1496     } else {
1497       // This thread will define the class (even if earlier thread tried and had an error)
1498       probe->set_definer(THREAD);
1499     }
1500   }
1501 
1502   define_instance_class(k, THREAD);
1503 
1504   Handle linkage_exception = Handle(); // null handle
1505 
1506   // definer must notify any waiting threads
1507   {
1508     MutexLocker mu(SystemDictionary_lock, THREAD);
1509     PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1510     assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1511     if (probe != NULL) {
1512       if (HAS_PENDING_EXCEPTION) {
1513         linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1514         CLEAR_PENDING_EXCEPTION;
1515       } else {
1516         probe->set_instance_klass(k());
1517       }
1518       probe->set_definer(NULL);
1519       placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1520       SystemDictionary_lock->notify_all();
1521     }
1522   }
1523 
1524   // Can't throw exception while holding lock due to rank ordering
1525   if (linkage_exception() != NULL) {
1526     THROW_OOP_(linkage_exception(), nh); // throws exception and returns
1527   }
1528 
1529   return k;
1530 }
1531 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1532   // If class_loader is NULL we synchronize on _system_loader_lock_obj
1533   if (class_loader.is_null()) {
1534     return Handle(THREAD, _system_loader_lock_obj);
1535   } else {
1536     return class_loader;
1537   }
1538 }
1539 
1540 // This method is added to check how often we have to wait to grab loader
1541 // lock. The results are being recorded in the performance counters defined in
1542 // ClassLoader::_sync_systemLoaderLockContentionRate and
1543 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1544 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1545   if (!UsePerfData) {
1546     return;
1547   }
1548 
1549   assert(!loader_lock.is_null(), "NULL lock object");
1550 
1551   if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1552       == ObjectSynchronizer::owner_other) {
1553     // contention will likely happen, so increment the corresponding
1554     // contention counter.
1555     if (loader_lock() == _system_loader_lock_obj) {
1556       ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1557     } else {
1558       ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1559     }
1560   }
1561 }
1562 
1563 // ----------------------------------------------------------------------------
1564 // Lookup
1565 
1566 Klass* SystemDictionary::find_class(int index, unsigned int hash,
1567                                       Symbol* class_name,
1568                                       ClassLoaderData* loader_data) {
1569   assert_locked_or_safepoint(SystemDictionary_lock);
1570   assert (index == dictionary()->index_for(class_name, loader_data),
1571           "incorrect index?");
1572 
1573   Klass* k = dictionary()->find_class(index, hash, class_name, loader_data);
1574   return k;
1575 }
1576 
1577 
1578 // Basic find on classes in the midst of being loaded
1579 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1580                                            ClassLoaderData* loader_data) {
1581   assert_locked_or_safepoint(SystemDictionary_lock);
1582   unsigned int p_hash = placeholders()->compute_hash(class_name, loader_data);
1583   int p_index = placeholders()->hash_to_index(p_hash);
1584   return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1585 }
1586 
1587 
1588 // Used for assertions and verification only
1589 Klass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1590   #ifndef ASSERT
1591   guarantee(VerifyBeforeGC      ||
1592             VerifyDuringGC      ||
1593             VerifyBeforeExit    ||
1594             VerifyDuringStartup ||
1595             VerifyAfterGC, "too expensive");
1596   #endif
1597   assert_locked_or_safepoint(SystemDictionary_lock);
1598 
1599   // First look in the loaded class array
1600   unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
1601   int d_index = dictionary()->hash_to_index(d_hash);
1602   return find_class(d_index, d_hash, class_name, loader_data);
1603 }
1604 
1605 
1606 // Get the next class in the diictionary.
1607 Klass* SystemDictionary::try_get_next_class() {
1608   return dictionary()->try_get_next_class();
1609 }
1610 
1611 
1612 // ----------------------------------------------------------------------------
1613 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1614 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1615 // before a new class is used.
1616 
1617 void SystemDictionary::add_to_hierarchy(instanceKlassHandle k, TRAPS) {
1618   assert(k.not_null(), "just checking");
1619   assert_locked_or_safepoint(Compile_lock);
1620 
1621   // Link into hierachy. Make sure the vtables are initialized before linking into
1622   k->append_to_sibling_list();                    // add to superklass/sibling list
1623   k->process_interfaces(THREAD);                  // handle all "implements" declarations
1624   k->set_init_state(InstanceKlass::loaded);
1625   // Now flush all code that depended on old class hierarchy.
1626   // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1627   // Also, first reinitialize vtable because it may have gotten out of synch
1628   // while the new class wasn't connected to the class hierarchy.
1629   CodeCache::flush_dependents_on(k);
1630 }
1631 
1632 // ----------------------------------------------------------------------------
1633 // GC support
1634 
1635 // Following roots during mark-sweep is separated in two phases.
1636 //
1637 // The first phase follows preloaded classes and all other system
1638 // classes, since these will never get unloaded anyway.
1639 //
1640 // The second phase removes (unloads) unreachable classes from the
1641 // system dictionary and follows the remaining classes' contents.
1642 
1643 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1644   roots_oops_do(blk, NULL);
1645 }
1646 
1647 void SystemDictionary::always_strong_classes_do(KlassClosure* closure) {
1648   // Follow all system classes and temporary placeholders in dictionary
1649   dictionary()->always_strong_classes_do(closure);
1650 
1651   // Placeholders. These represent classes we're actively loading.
1652   placeholders()->classes_do(closure);
1653 }
1654 
1655 // Calculate a "good" systemdictionary size based
1656 // on predicted or current loaded classes count
1657 int SystemDictionary::calculate_systemdictionary_size(int classcount) {
1658   int newsize = _old_default_sdsize;
1659   if ((classcount > 0)  && !DumpSharedSpaces) {
1660     int desiredsize = classcount/_average_depth_goal;
1661     for (newsize = _primelist[_sdgeneration]; _sdgeneration < _prime_array_size -1;
1662          newsize = _primelist[++_sdgeneration]) {
1663       if (desiredsize <=  newsize) {
1664         break;
1665       }
1666     }
1667   }
1668   return newsize;
1669 }
1670 
1671 #ifdef ASSERT
1672 class VerifySDReachableAndLiveClosure : public OopClosure {
1673 private:
1674   BoolObjectClosure* _is_alive;
1675 
1676   template <class T> void do_oop_work(T* p) {
1677     oop obj = oopDesc::load_decode_heap_oop(p);
1678     guarantee(_is_alive->do_object_b(obj), "Oop in system dictionary must be live");
1679   }
1680 
1681 public:
1682   VerifySDReachableAndLiveClosure(BoolObjectClosure* is_alive) : OopClosure(), _is_alive(is_alive) { }
1683 
1684   virtual void do_oop(oop* p)       { do_oop_work(p); }
1685   virtual void do_oop(narrowOop* p) { do_oop_work(p); }
1686 };
1687 #endif
1688 
1689 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1690 // Note: anonymous classes are not in the SD.
1691 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive,
1692                                     bool clean_previous_versions) {
1693   // First, mark for unload all ClassLoaderData referencing a dead class loader.
1694   bool unloading_occurred = ClassLoaderDataGraph::do_unloading(is_alive,
1695                                                                clean_previous_versions);
1696   if (unloading_occurred) {
1697     dictionary()->do_unloading();
1698     constraints()->purge_loader_constraints();
1699     resolution_errors()->purge_resolution_errors();
1700   }
1701   // Oops referenced by the system dictionary may get unreachable independently
1702   // of the class loader (eg. cached protection domain oops). So we need to
1703   // explicitly unlink them here instead of in Dictionary::do_unloading.
1704   dictionary()->unlink(is_alive);
1705 #ifdef ASSERT
1706   VerifySDReachableAndLiveClosure cl(is_alive);
1707   dictionary()->oops_do(&cl);
1708 #endif
1709   return unloading_occurred;
1710 }
1711 
1712 void SystemDictionary::roots_oops_do(OopClosure* strong, OopClosure* weak) {
1713   strong->do_oop(&_java_system_loader);
1714   strong->do_oop(&_system_loader_lock_obj);
1715   CDS_ONLY(SystemDictionaryShared::roots_oops_do(strong);)
1716 
1717   // Adjust dictionary
1718   dictionary()->roots_oops_do(strong, weak);
1719 
1720   // Visit extra methods
1721   invoke_method_table()->oops_do(strong);
1722 }
1723 
1724 void SystemDictionary::oops_do(OopClosure* f) {
1725   f->do_oop(&_java_system_loader);
1726   f->do_oop(&_system_loader_lock_obj);
1727   CDS_ONLY(SystemDictionaryShared::oops_do(f);)
1728 
1729   // Adjust dictionary
1730   dictionary()->oops_do(f);
1731 
1732   // Visit extra methods
1733   invoke_method_table()->oops_do(f);
1734 }
1735 
1736 // Extended Class redefinition support.
1737 // If one of these classes is replaced, we need to replace it in these places.
1738 // KlassClosure::do_klass should take the address of a class but we can
1739 // change that later.
1740 void SystemDictionary::preloaded_classes_do(KlassClosure* f) {
1741   for (int k = (int)FIRST_WKID; k < (int)WKID_LIMIT; k++) {
1742     f->do_klass(_well_known_klasses[k]);
1743   }
1744 
1745   {
1746     for (int i = 0; i < T_VOID+1; i++) {
1747       if (_box_klasses[i] != NULL) {
1748         assert(i >= T_BOOLEAN, "checking");
1749         f->do_klass(_box_klasses[i]);
1750       }
1751     }
1752   }
1753 
1754   FilteredFieldsMap::classes_do(f);
1755 }
1756 
1757 void SystemDictionary::lazily_loaded_classes_do(KlassClosure* f) {
1758   f->do_klass(_abstract_ownable_synchronizer_klass);
1759 }
1760 
1761 // Just the classes from defining class loaders
1762 // Don't iterate over placeholders
1763 void SystemDictionary::classes_do(void f(Klass*)) {
1764   dictionary()->classes_do(f);
1765 }
1766 
1767 // Added for initialize_itable_for_klass
1768 //   Just the classes from defining class loaders
1769 // Don't iterate over placeholders
1770 void SystemDictionary::classes_do(void f(Klass*, TRAPS), TRAPS) {
1771   dictionary()->classes_do(f, CHECK);
1772 }
1773 
1774 //   All classes, and their class loaders
1775 // Don't iterate over placeholders
1776 void SystemDictionary::classes_do(void f(Klass*, ClassLoaderData*)) {
1777   dictionary()->classes_do(f);
1778 }
1779 
1780 void SystemDictionary::placeholders_do(void f(Symbol*)) {
1781   placeholders()->entries_do(f);
1782 }
1783 
1784 void SystemDictionary::methods_do(void f(Method*)) {
1785   dictionary()->methods_do(f);
1786   invoke_method_table()->methods_do(f);
1787 }
1788 
1789 void SystemDictionary::remove_classes_in_error_state() {
1790   dictionary()->remove_classes_in_error_state();
1791 }
1792 
1793 // ----------------------------------------------------------------------------
1794 // Lazily load klasses
1795 
1796 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
1797   // if multiple threads calling this function, only one thread will load
1798   // the class.  The other threads will find the loaded version once the
1799   // class is loaded.
1800   Klass* aos = _abstract_ownable_synchronizer_klass;
1801   if (aos == NULL) {
1802     Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
1803     // Force a fence to prevent any read before the write completes
1804     OrderAccess::fence();
1805     _abstract_ownable_synchronizer_klass = k;
1806   }
1807 }
1808 
1809 // ----------------------------------------------------------------------------
1810 // Initialization
1811 
1812 void SystemDictionary::initialize(TRAPS) {
1813   // Allocate arrays
1814   assert(dictionary() == NULL,
1815          "SystemDictionary should only be initialized once");
1816   _sdgeneration        = 0;
1817   _dictionary          = new Dictionary(calculate_systemdictionary_size(PredictedLoadedClassCount));
1818   _placeholders        = new PlaceholderTable(_nof_buckets);
1819   _number_of_modifications = 0;
1820   _loader_constraints  = new LoaderConstraintTable(_loader_constraint_size);
1821   _resolution_errors   = new ResolutionErrorTable(_resolution_error_size);
1822   _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
1823 
1824   // Allocate private object used as system class loader lock
1825   _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
1826   // Initialize basic classes
1827   initialize_preloaded_classes(CHECK);
1828 }
1829 
1830 // Compact table of directions on the initialization of klasses:
1831 static const short wk_init_info[] = {
1832   #define WK_KLASS_INIT_INFO(name, symbol, option) \
1833     ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
1834           << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
1835       | (int)SystemDictionary::option ),
1836   WK_KLASSES_DO(WK_KLASS_INIT_INFO)
1837   #undef WK_KLASS_INIT_INFO
1838   0
1839 };
1840 
1841 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
1842   assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1843   int  info = wk_init_info[id - FIRST_WKID];
1844   int  sid  = (info >> CEIL_LG_OPTION_LIMIT);
1845   Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
1846   Klass**    klassp = &_well_known_klasses[id];
1847   bool must_load = (init_opt < SystemDictionary::Opt);
1848   if ((*klassp) == NULL) {
1849     if (must_load) {
1850       (*klassp) = resolve_or_fail(symbol, true, CHECK_0); // load required class
1851     } else {
1852       (*klassp) = resolve_or_null(symbol,       CHECK_0); // load optional klass
1853     }
1854   }
1855   return ((*klassp) != NULL);
1856 }
1857 
1858 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
1859   assert((int)start_id <= (int)limit_id, "IDs are out of order!");
1860   for (int id = (int)start_id; id < (int)limit_id; id++) {
1861     assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1862     int info = wk_init_info[id - FIRST_WKID];
1863     int sid  = (info >> CEIL_LG_OPTION_LIMIT);
1864     int opt  = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
1865 
1866     initialize_wk_klass((WKID)id, opt, CHECK);
1867   }
1868 
1869   // move the starting value forward to the limit:
1870   start_id = limit_id;
1871 }
1872 
1873 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
1874   assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
1875   // Preload commonly used klasses
1876   WKID scan = FIRST_WKID;
1877   // first do Object, then String, Class
1878   if (UseSharedSpaces) {
1879     initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
1880     // Initialize the constant pool for the Object_class
1881     InstanceKlass* ik = InstanceKlass::cast(Object_klass());
1882     ik->constants()->restore_unshareable_info(CHECK);
1883     initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1884   } else {
1885     initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1886   }
1887 
1888   // Calculate offsets for String and Class classes since they are loaded and
1889   // can be used after this point.
1890   java_lang_String::compute_offsets();
1891   java_lang_Class::compute_offsets();
1892 
1893   // Fixup mirrors for classes loaded before java.lang.Class.
1894   // These calls iterate over the objects currently in the perm gen
1895   // so calling them at this point is matters (not before when there
1896   // are fewer objects and not later after there are more objects
1897   // in the perm gen.
1898   Universe::initialize_basic_type_mirrors(CHECK);
1899   Universe::fixup_mirrors(CHECK);
1900 
1901   // do a bunch more:
1902   initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
1903 
1904   // Preload ref klasses and set reference types
1905   InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
1906   InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
1907 
1908   initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Cleaner_klass), scan, CHECK);
1909   InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
1910   InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
1911   InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
1912   InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
1913   InstanceKlass::cast(WK_KLASS(Cleaner_klass))->set_reference_type(REF_CLEANER);
1914 
1915   // JSR 292 classes
1916   WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
1917   WKID jsr292_group_end   = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
1918   initialize_wk_klasses_until(jsr292_group_start, scan, CHECK);
1919   initialize_wk_klasses_through(jsr292_group_end, scan, CHECK);
1920   initialize_wk_klasses_until(WKID_LIMIT, scan, CHECK);
1921 
1922   _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
1923   _box_klasses[T_CHAR]    = WK_KLASS(Character_klass);
1924   _box_klasses[T_FLOAT]   = WK_KLASS(Float_klass);
1925   _box_klasses[T_DOUBLE]  = WK_KLASS(Double_klass);
1926   _box_klasses[T_BYTE]    = WK_KLASS(Byte_klass);
1927   _box_klasses[T_SHORT]   = WK_KLASS(Short_klass);
1928   _box_klasses[T_INT]     = WK_KLASS(Integer_klass);
1929   _box_klasses[T_LONG]    = WK_KLASS(Long_klass);
1930   //_box_klasses[T_OBJECT]  = WK_KLASS(object_klass);
1931   //_box_klasses[T_ARRAY]   = WK_KLASS(object_klass);
1932 
1933   { // Compute whether we should use loadClass or loadClassInternal when loading classes.
1934     Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature());
1935     _has_loadClassInternal = (method != NULL);
1936   }
1937   { // Compute whether we should use checkPackageAccess or NOT
1938     Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
1939     _has_checkPackageAccess = (method != NULL);
1940   }
1941 }
1942 
1943 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
1944 // If so, returns the basic type it holds.  If not, returns T_OBJECT.
1945 BasicType SystemDictionary::box_klass_type(Klass* k) {
1946   assert(k != NULL, "");
1947   for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
1948     if (_box_klasses[i] == k)
1949       return (BasicType)i;
1950   }
1951   return T_OBJECT;
1952 }
1953 
1954 // Constraints on class loaders. The details of the algorithm can be
1955 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
1956 // Virtual Machine" by Sheng Liang and Gilad Bracha.  The basic idea is
1957 // that the system dictionary needs to maintain a set of contraints that
1958 // must be satisfied by all classes in the dictionary.
1959 // if defining is true, then LinkageError if already in systemDictionary
1960 // if initiating loader, then ok if InstanceKlass matches existing entry
1961 
1962 void SystemDictionary::check_constraints(int d_index, unsigned int d_hash,
1963                                          instanceKlassHandle k,
1964                                          Handle class_loader, bool defining,
1965                                          TRAPS) {
1966   const char *linkage_error = NULL;
1967   {
1968     Symbol*  name  = k->name();
1969     ClassLoaderData *loader_data = class_loader_data(class_loader);
1970 
1971     MutexLocker mu(SystemDictionary_lock, THREAD);
1972 
1973     Klass* check = find_class(d_index, d_hash, name, loader_data);
1974     if (check != (Klass*)NULL) {
1975       // if different InstanceKlass - duplicate class definition,
1976       // else - ok, class loaded by a different thread in parallel,
1977       // we should only have found it if it was done loading and ok to use
1978       // system dictionary only holds instance classes, placeholders
1979       // also holds array classes
1980 
1981       assert(check->oop_is_instance(), "noninstance in systemdictionary");
1982       if ((defining == true) || (k() != check)) {
1983         linkage_error = "loader (instance of  %s): attempted  duplicate class "
1984           "definition for name: \"%s\"";
1985       } else {
1986         return;
1987       }
1988     }
1989 
1990 #ifdef ASSERT
1991     Symbol* ph_check = find_placeholder(name, loader_data);
1992     assert(ph_check == NULL || ph_check->equals(name), "invalid symbol");
1993 #endif
1994 
1995     if (linkage_error == NULL) {
1996       if (constraints()->check_or_update(k, class_loader, name) == false) {
1997         linkage_error = "loader constraint violation: loader (instance of %s)"
1998           " previously initiated loading for a different type with name \"%s\"";
1999       }
2000     }
2001   }
2002 
2003   // Throw error now if needed (cannot throw while holding
2004   // SystemDictionary_lock because of rank ordering)
2005 
2006   if (linkage_error) {
2007     ResourceMark rm(THREAD);
2008     const char* class_loader_name = loader_name(class_loader());
2009     char* type_name = k->name()->as_C_string();
2010     size_t buflen = strlen(linkage_error) + strlen(class_loader_name) +
2011       strlen(type_name);
2012     char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
2013     jio_snprintf(buf, buflen, linkage_error, class_loader_name, type_name);
2014     THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
2015   }
2016 }
2017 
2018 
2019 // Update system dictionary - done after check_constraint and add_to_hierachy
2020 // have been called.
2021 void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash,
2022                                          int p_index, unsigned int p_hash,
2023                                          instanceKlassHandle k,
2024                                          Handle class_loader,
2025                                          TRAPS) {
2026   // Compile_lock prevents systemDictionary updates during compilations
2027   assert_locked_or_safepoint(Compile_lock);
2028   Symbol* name  = k->name();
2029   ClassLoaderData *loader_data = class_loader_data(class_loader);
2030 
2031   {
2032   MutexLocker mu1(SystemDictionary_lock, THREAD);
2033 
2034   // See whether biased locking is enabled and if so set it for this
2035   // klass.
2036   // Note that this must be done past the last potential blocking
2037   // point / safepoint. We enable biased locking lazily using a
2038   // VM_Operation to iterate the SystemDictionary and installing the
2039   // biasable mark word into each InstanceKlass's prototype header.
2040   // To avoid race conditions where we accidentally miss enabling the
2041   // optimization for one class in the process of being added to the
2042   // dictionary, we must not safepoint after the test of
2043   // BiasedLocking::enabled().
2044   if (UseBiasedLocking && BiasedLocking::enabled()) {
2045     // Set biased locking bit for all loaded classes; it will be
2046     // cleared if revocation occurs too often for this type
2047     // NOTE that we must only do this when the class is initally
2048     // defined, not each time it is referenced from a new class loader
2049     if (k->class_loader() == class_loader()) {
2050       k->set_prototype_header(markOopDesc::biased_locking_prototype());
2051     }
2052   }
2053 
2054   // Make a new system dictionary entry.
2055   Klass* sd_check = find_class(d_index, d_hash, name, loader_data);
2056   if (sd_check == NULL) {
2057     dictionary()->add_klass(name, loader_data, k);
2058     notice_modification();
2059   }
2060 #ifdef ASSERT
2061   sd_check = find_class(d_index, d_hash, name, loader_data);
2062   assert (sd_check != NULL, "should have entry in system dictionary");
2063   // Note: there may be a placeholder entry: for circularity testing
2064   // or for parallel defines
2065 #endif
2066     SystemDictionary_lock->notify_all();
2067   }
2068 }
2069 
2070 
2071 // Try to find a class name using the loader constraints.  The
2072 // loader constraints might know about a class that isn't fully loaded
2073 // yet and these will be ignored.
2074 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2075                     Symbol* class_name, Handle class_loader, TRAPS) {
2076 
2077   // First see if it has been loaded directly.
2078   // Force the protection domain to be null.  (This removes protection checks.)
2079   Handle no_protection_domain;
2080   Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2081                                               no_protection_domain, CHECK_NULL);
2082   if (klass != NULL)
2083     return klass;
2084 
2085   // Now look to see if it has been loaded elsewhere, and is subject to
2086   // a loader constraint that would require this loader to return the
2087   // klass that is already loaded.
2088   if (FieldType::is_array(class_name)) {
2089     // For array classes, their Klass*s are not kept in the
2090     // constraint table. The element Klass*s are.
2091     FieldArrayInfo fd;
2092     BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2093     if (t != T_OBJECT) {
2094       klass = Universe::typeArrayKlassObj(t);
2095     } else {
2096       MutexLocker mu(SystemDictionary_lock, THREAD);
2097       klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2098     }
2099     // If element class already loaded, allocate array klass
2100     if (klass != NULL) {
2101       klass = klass->array_klass_or_null(fd.dimension());
2102     }
2103   } else {
2104     MutexLocker mu(SystemDictionary_lock, THREAD);
2105     // Non-array classes are easy: simply check the constraint table.
2106     klass = constraints()->find_constrained_klass(class_name, class_loader);
2107   }
2108 
2109   return klass;
2110 }
2111 
2112 
2113 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2114                                              Handle class_loader1,
2115                                              Handle class_loader2,
2116                                              Thread* THREAD) {
2117   ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2118   ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2119 
2120   Symbol* constraint_name = NULL;
2121   if (!FieldType::is_array(class_name)) {
2122     constraint_name = class_name;
2123   } else {
2124     // For array classes, their Klass*s are not kept in the
2125     // constraint table. The element classes are.
2126     FieldArrayInfo fd;
2127     BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2128     // primitive types always pass
2129     if (t != T_OBJECT) {
2130       return true;
2131     } else {
2132       constraint_name = fd.object_key();
2133     }
2134   }
2135   unsigned int d_hash1 = dictionary()->compute_hash(constraint_name, loader_data1);
2136   int d_index1 = dictionary()->hash_to_index(d_hash1);
2137 
2138   unsigned int d_hash2 = dictionary()->compute_hash(constraint_name, loader_data2);
2139   int d_index2 = dictionary()->hash_to_index(d_hash2);
2140   {
2141   MutexLocker mu_s(SystemDictionary_lock, THREAD);
2142 
2143   // Better never do a GC while we're holding these oops
2144   No_Safepoint_Verifier nosafepoint;
2145 
2146   Klass* klass1 = find_class(d_index1, d_hash1, constraint_name, loader_data1);
2147   Klass* klass2 = find_class(d_index2, d_hash2, constraint_name, loader_data2);
2148   return constraints()->add_entry(constraint_name, klass1, class_loader1,
2149                                   klass2, class_loader2);
2150   }
2151 }
2152 
2153 // Add entry to resolution error table to record the error when the first
2154 // attempt to resolve a reference to a class has failed.
2155 void SystemDictionary::add_resolution_error(constantPoolHandle pool, int which,
2156                                             Symbol* error, Symbol* message) {
2157   unsigned int hash = resolution_errors()->compute_hash(pool, which);
2158   int index = resolution_errors()->hash_to_index(hash);
2159   {
2160     MutexLocker ml(SystemDictionary_lock, Thread::current());
2161     resolution_errors()->add_entry(index, hash, pool, which, error, message);
2162   }
2163 }
2164 
2165 // Delete a resolution error for RedefineClasses for a constant pool is going away
2166 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2167   resolution_errors()->delete_entry(pool);
2168 }
2169 
2170 // Lookup resolution error table. Returns error if found, otherwise NULL.
2171 Symbol* SystemDictionary::find_resolution_error(constantPoolHandle pool, int which,
2172                                                 Symbol** message) {
2173   unsigned int hash = resolution_errors()->compute_hash(pool, which);
2174   int index = resolution_errors()->hash_to_index(hash);
2175   {
2176     MutexLocker ml(SystemDictionary_lock, Thread::current());
2177     ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2178     if (entry != NULL) {
2179       *message = entry->message();
2180       return entry->error();
2181     } else {
2182       return NULL;
2183     }
2184   }
2185 }
2186 
2187 
2188 // Signature constraints ensure that callers and callees agree about
2189 // the meaning of type names in their signatures.  This routine is the
2190 // intake for constraints.  It collects them from several places:
2191 //
2192 //  * LinkResolver::resolve_method (if check_access is true) requires
2193 //    that the resolving class (the caller) and the defining class of
2194 //    the resolved method (the callee) agree on each type in the
2195 //    method's signature.
2196 //
2197 //  * LinkResolver::resolve_interface_method performs exactly the same
2198 //    checks.
2199 //
2200 //  * LinkResolver::resolve_field requires that the constant pool
2201 //    attempting to link to a field agree with the field's defining
2202 //    class about the type of the field signature.
2203 //
2204 //  * klassVtable::initialize_vtable requires that, when a class
2205 //    overrides a vtable entry allocated by a superclass, that the
2206 //    overriding method (i.e., the callee) agree with the superclass
2207 //    on each type in the method's signature.
2208 //
2209 //  * klassItable::initialize_itable requires that, when a class fills
2210 //    in its itables, for each non-abstract method installed in an
2211 //    itable, the method (i.e., the callee) agree with the interface
2212 //    on each type in the method's signature.
2213 //
2214 // All those methods have a boolean (check_access, checkconstraints)
2215 // which turns off the checks.  This is used from specialized contexts
2216 // such as bootstrapping, dumping, and debugging.
2217 //
2218 // No direct constraint is placed between the class and its
2219 // supertypes.  Constraints are only placed along linked relations
2220 // between callers and callees.  When a method overrides or implements
2221 // an abstract method in a supertype (superclass or interface), the
2222 // constraints are placed as if the supertype were the caller to the
2223 // overriding method.  (This works well, since callers to the
2224 // supertype have already established agreement between themselves and
2225 // the supertype.)  As a result of all this, a class can disagree with
2226 // its supertype about the meaning of a type name, as long as that
2227 // class neither calls a relevant method of the supertype, nor is
2228 // called (perhaps via an override) from the supertype.
2229 //
2230 //
2231 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2232 //
2233 // Make sure all class components (including arrays) in the given
2234 // signature will be resolved to the same class in both loaders.
2235 // Returns the name of the type that failed a loader constraint check, or
2236 // NULL if no constraint failed.  No exception except OOME is thrown.
2237 // Arrays are not added to the loader constraint table, their elements are.
2238 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2239                                                Handle loader1, Handle loader2,
2240                                                bool is_method, TRAPS)  {
2241   // Nothing to do if loaders are the same.
2242   if (loader1() == loader2()) {
2243     return NULL;
2244   }
2245 
2246   SignatureStream sig_strm(signature, is_method);
2247   while (!sig_strm.is_done()) {
2248     if (sig_strm.is_object()) {
2249       Symbol* sig = sig_strm.as_symbol(CHECK_NULL);
2250       if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2251         return sig;
2252       }
2253     }
2254     sig_strm.next();
2255   }
2256   return NULL;
2257 }
2258 
2259 
2260 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2261                                                             Symbol* signature,
2262                                                             TRAPS) {
2263   methodHandle empty;
2264   assert(MethodHandles::is_signature_polymorphic(iid) &&
2265          MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2266          iid != vmIntrinsics::_invokeGeneric,
2267          err_msg("must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid)));
2268 
2269   unsigned int hash  = invoke_method_table()->compute_hash(signature, iid);
2270   int          index = invoke_method_table()->hash_to_index(hash);
2271   SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2272   methodHandle m;
2273   if (spe == NULL || spe->method() == NULL) {
2274     spe = NULL;
2275     // Must create lots of stuff here, but outside of the SystemDictionary lock.
2276     m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2277     if (!Arguments::is_interpreter_only()) {
2278       // Generate a compiled form of the MH intrinsic.
2279       AdapterHandlerLibrary::create_native_wrapper(m);
2280       // Check if have the compiled code.
2281       if (!m->has_compiled_code()) {
2282         THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(),
2283                    "out of space in CodeCache for method handle intrinsic", empty);
2284       }
2285     }
2286     // Now grab the lock.  We might have to throw away the new method,
2287     // if a racing thread has managed to install one at the same time.
2288     {
2289       MutexLocker ml(SystemDictionary_lock, THREAD);
2290       spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2291       if (spe == NULL)
2292         spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2293       if (spe->method() == NULL)
2294         spe->set_method(m());
2295     }
2296   }
2297 
2298   assert(spe != NULL && spe->method() != NULL, "");
2299   assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2300          spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2301          "MH intrinsic invariant");
2302   return spe->method();
2303 }
2304 
2305 // Helper for unpacking the return value from linkMethod and linkCallSite.
2306 static methodHandle unpack_method_and_appendix(Handle mname,
2307                                                KlassHandle accessing_klass,
2308                                                objArrayHandle appendix_box,
2309                                                Handle* appendix_result,
2310                                                TRAPS) {
2311   methodHandle empty;
2312   if (mname.not_null()) {
2313     Metadata* vmtarget = java_lang_invoke_MemberName::vmtarget(mname());
2314     if (vmtarget != NULL && vmtarget->is_method()) {
2315       Method* m = (Method*)vmtarget;
2316       oop appendix = appendix_box->obj_at(0);
2317       if (TraceMethodHandles) {
2318     #ifndef PRODUCT
2319         tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2320         m->print();
2321         if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2322         tty->cr();
2323     #endif //PRODUCT
2324       }
2325       (*appendix_result) = Handle(THREAD, appendix);
2326       // the target is stored in the cpCache and if a reference to this
2327       // MethodName is dropped we need a way to make sure the
2328       // class_loader containing this method is kept alive.
2329       // FIXME: the appendix might also preserve this dependency.
2330       ClassLoaderData* this_key = InstanceKlass::cast(accessing_klass())->class_loader_data();
2331       this_key->record_dependency(m->method_holder(), CHECK_NULL); // Can throw OOM
2332       return methodHandle(THREAD, m);
2333     }
2334   }
2335   THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2336   return empty;
2337 }
2338 
2339 methodHandle SystemDictionary::find_method_handle_invoker(Symbol* name,
2340                                                           Symbol* signature,
2341                                                           KlassHandle accessing_klass,
2342                                                           Handle *appendix_result,
2343                                                           Handle *method_type_result,
2344                                                           TRAPS) {
2345   methodHandle empty;
2346   assert(!THREAD->is_Compiler_thread(), "");
2347   Handle method_type =
2348     SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2349   if (false) {  // FIXME: Decide if the Java upcall should resolve signatures.
2350     method_type = java_lang_String::create_from_symbol(signature, CHECK_(empty));
2351   }
2352 
2353   KlassHandle  mh_klass = SystemDictionary::MethodHandle_klass();
2354   int ref_kind = JVM_REF_invokeVirtual;
2355   Handle name_str = StringTable::intern(name, CHECK_(empty));
2356   objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2357   assert(appendix_box->obj_at(0) == NULL, "");
2358 
2359   // This should not happen.  JDK code should take care of that.
2360   if (accessing_klass.is_null() || method_type.is_null()) {
2361     THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
2362   }
2363 
2364   // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2365   JavaCallArguments args;
2366   args.push_oop(accessing_klass()->java_mirror());
2367   args.push_int(ref_kind);
2368   args.push_oop(mh_klass()->java_mirror());
2369   args.push_oop(name_str());
2370   args.push_oop(method_type());
2371   args.push_oop(appendix_box());
2372   JavaValue result(T_OBJECT);
2373   JavaCalls::call_static(&result,
2374                          SystemDictionary::MethodHandleNatives_klass(),
2375                          vmSymbols::linkMethod_name(),
2376                          vmSymbols::linkMethod_signature(),
2377                          &args, CHECK_(empty));
2378   Handle mname(THREAD, (oop) result.get_jobject());
2379   (*method_type_result) = method_type;
2380   return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2381 }
2382 
2383 
2384 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2385 // signature, as interpreted relative to the given class loader.
2386 // Because of class loader constraints, all method handle usage must be
2387 // consistent with this loader.
2388 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2389                                                  KlassHandle accessing_klass,
2390                                                  TRAPS) {
2391   Handle empty;
2392   vmIntrinsics::ID null_iid = vmIntrinsics::_none;  // distinct from all method handle invoker intrinsics
2393   unsigned int hash  = invoke_method_table()->compute_hash(signature, null_iid);
2394   int          index = invoke_method_table()->hash_to_index(hash);
2395   SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2396   if (spe != NULL && spe->method_type() != NULL) {
2397     assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2398     return Handle(THREAD, spe->method_type());
2399   } else if (THREAD->is_Compiler_thread()) {
2400     warning("SystemDictionary::find_method_handle_type called from compiler thread");  // FIXME
2401     return Handle();  // do not attempt from within compiler, unless it was cached
2402   }
2403 
2404   Handle class_loader, protection_domain;
2405   bool is_on_bcp = true;  // keep this true as long as we can materialize from the boot classloader
2406   int npts = ArgumentCount(signature).size();
2407   objArrayHandle pts = oopFactory::new_objArray(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2408   int arg = 0;
2409   Handle rt;                            // the return type from the signature
2410   ResourceMark rm(THREAD);
2411   for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2412     oop mirror = NULL;
2413     if (is_on_bcp) {
2414       // Note:  class_loader & protection_domain are both null at this point.
2415       mirror = ss.as_java_mirror(class_loader, protection_domain,
2416                                  SignatureStream::ReturnNull, CHECK_(empty));
2417       if (mirror == NULL) {
2418         // fall back from BCP to accessing_klass
2419         if (accessing_klass.not_null()) {
2420           class_loader      = Handle(THREAD, InstanceKlass::cast(accessing_klass())->class_loader());
2421           protection_domain = Handle(THREAD, InstanceKlass::cast(accessing_klass())->protection_domain());
2422         }
2423         is_on_bcp = false;
2424       }
2425     }
2426     if (!is_on_bcp) {
2427       // Resolve, throwing a real error if it doesn't work.
2428       mirror = ss.as_java_mirror(class_loader, protection_domain,
2429                                  SignatureStream::NCDFError, CHECK_(empty));
2430     }
2431     if (ss.at_return_type())
2432       rt = Handle(THREAD, mirror);
2433     else
2434       pts->obj_at_put(arg++, mirror);
2435 
2436     // Check accessibility.
2437     if (ss.is_object() && accessing_klass.not_null()) {
2438       Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2439       mirror = NULL;  // safety
2440       // Emulate ConstantPool::verify_constant_pool_resolve.
2441       if (sel_klass->oop_is_objArray())
2442         sel_klass = ObjArrayKlass::cast(sel_klass)->bottom_klass();
2443       if (sel_klass->oop_is_instance()) {
2444         KlassHandle sel_kh(THREAD, sel_klass);
2445         LinkResolver::check_klass_accessability(accessing_klass, sel_kh, CHECK_(empty));
2446       }
2447     }
2448   }
2449   assert(arg == npts, "");
2450 
2451   // call java.lang.invoke.MethodHandleNatives::findMethodType(Class rt, Class[] pts) -> MethodType
2452   JavaCallArguments args(Handle(THREAD, rt()));
2453   args.push_oop(pts());
2454   JavaValue result(T_OBJECT);
2455   JavaCalls::call_static(&result,
2456                          SystemDictionary::MethodHandleNatives_klass(),
2457                          vmSymbols::findMethodHandleType_name(),
2458                          vmSymbols::findMethodHandleType_signature(),
2459                          &args, CHECK_(empty));
2460   Handle method_type(THREAD, (oop) result.get_jobject());
2461 
2462   if (is_on_bcp) {
2463     // We can cache this MethodType inside the JVM.
2464     MutexLocker ml(SystemDictionary_lock, THREAD);
2465     spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2466     if (spe == NULL)
2467       spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2468     if (spe->method_type() == NULL) {
2469       spe->set_method_type(method_type());
2470     }
2471   }
2472 
2473   // report back to the caller with the MethodType
2474   return method_type;
2475 }
2476 
2477 // Ask Java code to find or construct a method handle constant.
2478 Handle SystemDictionary::link_method_handle_constant(KlassHandle caller,
2479                                                      int ref_kind, //e.g., JVM_REF_invokeVirtual
2480                                                      KlassHandle callee,
2481                                                      Symbol* name_sym,
2482                                                      Symbol* signature,
2483                                                      TRAPS) {
2484   Handle empty;
2485   Handle name = java_lang_String::create_from_symbol(name_sym, CHECK_(empty));
2486   Handle type;
2487   if (signature->utf8_length() > 0 && signature->byte_at(0) == '(') {
2488     type = find_method_handle_type(signature, caller, CHECK_(empty));
2489   } else if (caller.is_null()) {
2490     // This should not happen.  JDK code should take care of that.
2491     THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2492   } else {
2493     ResourceMark rm(THREAD);
2494     SignatureStream ss(signature, false);
2495     if (!ss.is_done()) {
2496       oop mirror = ss.as_java_mirror(caller->class_loader(), caller->protection_domain(),
2497                                      SignatureStream::NCDFError, CHECK_(empty));
2498       type = Handle(THREAD, mirror);
2499       ss.next();
2500       if (!ss.is_done())  type = Handle();  // error!
2501     }
2502   }
2503   if (type.is_null()) {
2504     THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad signature", empty);
2505   }
2506 
2507   // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2508   JavaCallArguments args;
2509   args.push_oop(caller->java_mirror());  // the referring class
2510   args.push_int(ref_kind);
2511   args.push_oop(callee->java_mirror());  // the target class
2512   args.push_oop(name());
2513   args.push_oop(type());
2514   JavaValue result(T_OBJECT);
2515   JavaCalls::call_static(&result,
2516                          SystemDictionary::MethodHandleNatives_klass(),
2517                          vmSymbols::linkMethodHandleConstant_name(),
2518                          vmSymbols::linkMethodHandleConstant_signature(),
2519                          &args, CHECK_(empty));
2520   return Handle(THREAD, (oop) result.get_jobject());
2521 }
2522 
2523 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2524 // name and signature, as interpreted relative to the given class loader.
2525 methodHandle SystemDictionary::find_dynamic_call_site_invoker(KlassHandle caller,
2526                                                               Handle bootstrap_specifier,
2527                                                               Symbol* name,
2528                                                               Symbol* type,
2529                                                               Handle *appendix_result,
2530                                                               Handle *method_type_result,
2531                                                               TRAPS) {
2532   methodHandle empty;
2533   Handle bsm, info;
2534   if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2535     bsm = bootstrap_specifier;
2536   } else {
2537     assert(bootstrap_specifier->is_objArray(), "");
2538     objArrayHandle args(THREAD, (objArrayOop) bootstrap_specifier());
2539     int len = args->length();
2540     assert(len >= 1, "");
2541     bsm = Handle(THREAD, args->obj_at(0));
2542     if (len > 1) {
2543       objArrayOop args1 = oopFactory::new_objArray(SystemDictionary::Object_klass(), len-1, CHECK_(empty));
2544       for (int i = 1; i < len; i++)
2545         args1->obj_at_put(i-1, args->obj_at(i));
2546       info = Handle(THREAD, args1);
2547     }
2548   }
2549   guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2550             "caller must supply a valid BSM");
2551 
2552   Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2553   Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2554 
2555   // This should not happen.  JDK code should take care of that.
2556   if (caller.is_null() || method_type.is_null()) {
2557     THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty);
2558   }
2559 
2560   objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2561   assert(appendix_box->obj_at(0) == NULL, "");
2562 
2563   // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, bsm, name, mtype, info, &appendix)
2564   JavaCallArguments args;
2565   args.push_oop(caller->java_mirror());
2566   args.push_oop(bsm());
2567   args.push_oop(method_name());
2568   args.push_oop(method_type());
2569   args.push_oop(info());
2570   args.push_oop(appendix_box);
2571   JavaValue result(T_OBJECT);
2572   JavaCalls::call_static(&result,
2573                          SystemDictionary::MethodHandleNatives_klass(),
2574                          vmSymbols::linkCallSite_name(),
2575                          vmSymbols::linkCallSite_signature(),
2576                          &args, CHECK_(empty));
2577   Handle mname(THREAD, (oop) result.get_jobject());
2578   (*method_type_result) = method_type;
2579   return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
2580 }
2581 
2582 // Since the identity hash code for symbols changes when the symbols are
2583 // moved from the regular perm gen (hash in the mark word) to the shared
2584 // spaces (hash is the address), the classes loaded into the dictionary
2585 // may be in the wrong buckets.
2586 
2587 void SystemDictionary::reorder_dictionary() {
2588   dictionary()->reorder_dictionary();
2589 }
2590 
2591 
2592 void SystemDictionary::copy_buckets(char** top, char* end) {
2593   dictionary()->copy_buckets(top, end);
2594 }
2595 
2596 
2597 void SystemDictionary::copy_table(char** top, char* end) {
2598   dictionary()->copy_table(top, end);
2599 }
2600 
2601 
2602 void SystemDictionary::reverse() {
2603   dictionary()->reverse();
2604 }
2605 
2606 int SystemDictionary::number_of_classes() {
2607   return dictionary()->number_of_entries();
2608 }
2609 
2610 
2611 // ----------------------------------------------------------------------------
2612 void SystemDictionary::print_shared(bool details) {
2613   shared_dictionary()->print(details);
2614 }
2615 
2616 void SystemDictionary::print(bool details) {
2617   dictionary()->print(details);
2618 
2619   // Placeholders
2620   GCMutexLocker mu(SystemDictionary_lock);
2621   placeholders()->print();
2622 
2623   // loader constraints - print under SD_lock
2624   constraints()->print();
2625 }
2626 
2627 
2628 void SystemDictionary::verify() {
2629   guarantee(dictionary() != NULL, "Verify of system dictionary failed");
2630   guarantee(constraints() != NULL,
2631             "Verify of loader constraints failed");
2632   guarantee(dictionary()->number_of_entries() >= 0 &&
2633             placeholders()->number_of_entries() >= 0,
2634             "Verify of system dictionary failed");
2635 
2636   // Verify dictionary
2637   dictionary()->verify();
2638 
2639   GCMutexLocker mu(SystemDictionary_lock);
2640   placeholders()->verify();
2641 
2642   // Verify constraint table
2643   guarantee(constraints() != NULL, "Verify of loader constraints failed");
2644   constraints()->verify(dictionary(), placeholders());
2645 }
2646 
2647 // utility function for class load event
2648 void SystemDictionary::post_class_load_event(const Ticks& start_time,
2649                                              instanceKlassHandle k,
2650                                              Handle initiating_loader) {
2651 #if INCLUDE_TRACE
2652   EventClassLoad event(UNTIMED);
2653   if (event.should_commit()) {
2654     event.set_starttime(start_time);
2655     event.set_loadedClass(k());
2656     oop defining_class_loader = k->class_loader();
2657     event.set_definingClassLoader(defining_class_loader !=  NULL ?
2658                                     defining_class_loader->klass() : (Klass*)NULL);
2659     oop class_loader = initiating_loader.is_null() ? (oop)NULL : initiating_loader();
2660     event.set_initiatingClassLoader(class_loader != NULL ?
2661                                       class_loader->klass() : (Klass*)NULL);
2662     event.commit();
2663   }
2664 #endif // INCLUDE_TRACE
2665 }
2666 
2667 #ifndef PRODUCT
2668 
2669 // statistics code
2670 class ClassStatistics: AllStatic {
2671  private:
2672   static int nclasses;        // number of classes
2673   static int nmethods;        // number of methods
2674   static int nmethoddata;     // number of methodData
2675   static int class_size;      // size of class objects in words
2676   static int method_size;     // size of method objects in words
2677   static int debug_size;      // size of debug info in methods
2678   static int methoddata_size; // size of methodData objects in words
2679 
2680   static void do_class(Klass* k) {
2681     nclasses++;
2682     class_size += k->size();
2683     if (k->oop_is_instance()) {
2684       InstanceKlass* ik = (InstanceKlass*)k;
2685       class_size += ik->methods()->size();
2686       class_size += ik->constants()->size();
2687       class_size += ik->local_interfaces()->size();
2688       class_size += ik->transitive_interfaces()->size();
2689       // We do not have to count implementors, since we only store one!
2690       // SSS: How should these be accounted now that they have moved?
2691       // class_size += ik->fields()->length();
2692     }
2693   }
2694 
2695   static void do_method(Method* m) {
2696     nmethods++;
2697     method_size += m->size();
2698     // class loader uses same objArray for empty vectors, so don't count these
2699     if (m->has_stackmap_table()) {
2700       method_size += m->stackmap_data()->size();
2701     }
2702 
2703     MethodData* mdo = m->method_data();
2704     if (mdo != NULL) {
2705       nmethoddata++;
2706       methoddata_size += mdo->size();
2707     }
2708   }
2709 
2710  public:
2711   static void print() {
2712     SystemDictionary::classes_do(do_class);
2713     SystemDictionary::methods_do(do_method);
2714     tty->print_cr("Class statistics:");
2715     tty->print_cr("%d classes (%d bytes)", nclasses, class_size * oopSize);
2716     tty->print_cr("%d methods (%d bytes = %d base + %d debug info)", nmethods,
2717                   (method_size + debug_size) * oopSize, method_size * oopSize, debug_size * oopSize);
2718     tty->print_cr("%d methoddata (%d bytes)", nmethoddata, methoddata_size * oopSize);
2719   }
2720 };
2721 
2722 
2723 int ClassStatistics::nclasses        = 0;
2724 int ClassStatistics::nmethods        = 0;
2725 int ClassStatistics::nmethoddata     = 0;
2726 int ClassStatistics::class_size      = 0;
2727 int ClassStatistics::method_size     = 0;
2728 int ClassStatistics::debug_size      = 0;
2729 int ClassStatistics::methoddata_size = 0;
2730 
2731 void SystemDictionary::print_class_statistics() {
2732   ResourceMark rm;
2733   ClassStatistics::print();
2734 }
2735 
2736 
2737 class MethodStatistics: AllStatic {
2738  public:
2739   enum {
2740     max_parameter_size = 10
2741   };
2742  private:
2743 
2744   static int _number_of_methods;
2745   static int _number_of_final_methods;
2746   static int _number_of_static_methods;
2747   static int _number_of_native_methods;
2748   static int _number_of_synchronized_methods;
2749   static int _number_of_profiled_methods;
2750   static int _number_of_bytecodes;
2751   static int _parameter_size_profile[max_parameter_size];
2752   static int _bytecodes_profile[Bytecodes::number_of_java_codes];
2753 
2754   static void initialize() {
2755     _number_of_methods        = 0;
2756     _number_of_final_methods  = 0;
2757     _number_of_static_methods = 0;
2758     _number_of_native_methods = 0;
2759     _number_of_synchronized_methods = 0;
2760     _number_of_profiled_methods = 0;
2761     _number_of_bytecodes      = 0;
2762     for (int i = 0; i < max_parameter_size             ; i++) _parameter_size_profile[i] = 0;
2763     for (int j = 0; j < Bytecodes::number_of_java_codes; j++) _bytecodes_profile     [j] = 0;
2764   };
2765 
2766   static void do_method(Method* m) {
2767     _number_of_methods++;
2768     // collect flag info
2769     if (m->is_final()       ) _number_of_final_methods++;
2770     if (m->is_static()      ) _number_of_static_methods++;
2771     if (m->is_native()      ) _number_of_native_methods++;
2772     if (m->is_synchronized()) _number_of_synchronized_methods++;
2773     if (m->method_data() != NULL) _number_of_profiled_methods++;
2774     // collect parameter size info (add one for receiver, if any)
2775     _parameter_size_profile[MIN2(m->size_of_parameters() + (m->is_static() ? 0 : 1), max_parameter_size - 1)]++;
2776     // collect bytecodes info
2777     {
2778       Thread *thread = Thread::current();
2779       HandleMark hm(thread);
2780       BytecodeStream s(methodHandle(thread, m));
2781       Bytecodes::Code c;
2782       while ((c = s.next()) >= 0) {
2783         _number_of_bytecodes++;
2784         _bytecodes_profile[c]++;
2785       }
2786     }
2787   }
2788 
2789  public:
2790   static void print() {
2791     initialize();
2792     SystemDictionary::methods_do(do_method);
2793     // generate output
2794     tty->cr();
2795     tty->print_cr("Method statistics (static):");
2796     // flag distribution
2797     tty->cr();
2798     tty->print_cr("%6d final        methods  %6.1f%%", _number_of_final_methods       , _number_of_final_methods        * 100.0F / _number_of_methods);
2799     tty->print_cr("%6d static       methods  %6.1f%%", _number_of_static_methods      , _number_of_static_methods       * 100.0F / _number_of_methods);
2800     tty->print_cr("%6d native       methods  %6.1f%%", _number_of_native_methods      , _number_of_native_methods       * 100.0F / _number_of_methods);
2801     tty->print_cr("%6d synchronized methods  %6.1f%%", _number_of_synchronized_methods, _number_of_synchronized_methods * 100.0F / _number_of_methods);
2802     tty->print_cr("%6d profiled     methods  %6.1f%%", _number_of_profiled_methods, _number_of_profiled_methods * 100.0F / _number_of_methods);
2803     // parameter size profile
2804     tty->cr();
2805     { int tot = 0;
2806       int avg = 0;
2807       for (int i = 0; i < max_parameter_size; i++) {
2808         int n = _parameter_size_profile[i];
2809         tot += n;
2810         avg += n*i;
2811         tty->print_cr("parameter size = %1d: %6d methods  %5.1f%%", i, n, n * 100.0F / _number_of_methods);
2812       }
2813       assert(tot == _number_of_methods, "should be the same");
2814       tty->print_cr("                    %6d methods  100.0%%", _number_of_methods);
2815       tty->print_cr("(average parameter size = %3.1f including receiver, if any)", (float)avg / _number_of_methods);
2816     }
2817     // bytecodes profile
2818     tty->cr();
2819     { int tot = 0;
2820       for (int i = 0; i < Bytecodes::number_of_java_codes; i++) {
2821         if (Bytecodes::is_defined(i)) {
2822           Bytecodes::Code c = Bytecodes::cast(i);
2823           int n = _bytecodes_profile[c];
2824           tot += n;
2825           tty->print_cr("%9d  %7.3f%%  %s", n, n * 100.0F / _number_of_bytecodes, Bytecodes::name(c));
2826         }
2827       }
2828       assert(tot == _number_of_bytecodes, "should be the same");
2829       tty->print_cr("%9d  100.000%%", _number_of_bytecodes);
2830     }
2831     tty->cr();
2832   }
2833 };
2834 
2835 int MethodStatistics::_number_of_methods;
2836 int MethodStatistics::_number_of_final_methods;
2837 int MethodStatistics::_number_of_static_methods;
2838 int MethodStatistics::_number_of_native_methods;
2839 int MethodStatistics::_number_of_synchronized_methods;
2840 int MethodStatistics::_number_of_profiled_methods;
2841 int MethodStatistics::_number_of_bytecodes;
2842 int MethodStatistics::_parameter_size_profile[MethodStatistics::max_parameter_size];
2843 int MethodStatistics::_bytecodes_profile[Bytecodes::number_of_java_codes];
2844 
2845 
2846 void SystemDictionary::print_method_statistics() {
2847   MethodStatistics::print();
2848 }
2849 
2850 #endif // PRODUCT