1 /*
   2  * Copyright (c) 1997, 2013, 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.hpp"
  29 #include "classfile/loaderConstraints.hpp"
  30 #include "classfile/placeholders.hpp"
  31 #include "classfile/resolutionErrors.hpp"
  32 #include "classfile/systemDictionary.hpp"
  33 #include "classfile/vmSymbols.hpp"
  34 #include "compiler/compileBroker.hpp"
  35 #include "interpreter/bytecodeStream.hpp"
  36 #include "interpreter/interpreter.hpp"
  37 #include "memory/gcLocker.hpp"
  38 #include "memory/oopFactory.hpp"
  39 #include "oops/instanceKlass.hpp"
  40 #include "oops/instanceRefKlass.hpp"
  41 #include "oops/klass.inline.hpp"
  42 #include "oops/methodData.hpp"
  43 #include "oops/objArrayKlass.hpp"
  44 #include "oops/oop.inline.hpp"
  45 #include "oops/oop.inline2.hpp"
  46 #include "oops/typeArrayKlass.hpp"
  47 #include "prims/jvmtiEnvBase.hpp"
  48 #include "prims/methodHandles.hpp"
  49 #include "runtime/biasedLocking.hpp"
  50 #include "runtime/fieldType.hpp"
  51 #include "runtime/handles.inline.hpp"
  52 #include "runtime/java.hpp"
  53 #include "runtime/javaCalls.hpp"
  54 #include "runtime/mutexLocker.hpp"
  55 #include "runtime/signature.hpp"
  56 #include "services/classLoadingService.hpp"
  57 #include "services/threadService.hpp"
  58 
  59 #if INCLUDE_TRACE
  60  #include "trace/tracing.hpp"
  61  #include "trace/traceMacros.hpp"
  62 #endif
  63 
  64 
  65 Dictionary*            SystemDictionary::_dictionary          = NULL;
  66 PlaceholderTable*      SystemDictionary::_placeholders        = NULL;
  67 Dictionary*            SystemDictionary::_shared_dictionary   = NULL;
  68 LoaderConstraintTable* SystemDictionary::_loader_constraints  = NULL;
  69 ResolutionErrorTable*  SystemDictionary::_resolution_errors   = NULL;
  70 SymbolPropertyTable*   SystemDictionary::_invoke_method_table = NULL;
  71 
  72 
  73 int         SystemDictionary::_number_of_modifications = 0;
  74 int         SystemDictionary::_sdgeneration               = 0;
  75 const int   SystemDictionary::_primelist[_prime_array_size] = {1009,2017,4049,5051,10103,
  76               20201,40423,99991};
  77 
  78 oop         SystemDictionary::_system_loader_lock_obj     =  NULL;
  79 
  80 Klass*      SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
  81                                                           =  { NULL /*, NULL...*/ };
  82 
  83 Klass*      SystemDictionary::_box_klasses[T_VOID+1]      =  { NULL /*, NULL...*/ };
  84 
  85 oop         SystemDictionary::_java_system_loader         =  NULL;
  86 
  87 bool        SystemDictionary::_has_loadClassInternal      =  false;
  88 bool        SystemDictionary::_has_checkPackageAccess     =  false;
  89 
  90 // lazily initialized klass variables
  91 Klass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
  92 
  93 
  94 // ----------------------------------------------------------------------------
  95 // Java-level SystemLoader
  96 
  97 oop SystemDictionary::java_system_loader() {
  98   return _java_system_loader;
  99 }
 100 
 101 void SystemDictionary::compute_java_system_loader(TRAPS) {
 102   KlassHandle system_klass(THREAD, WK_KLASS(ClassLoader_klass));
 103   JavaValue result(T_OBJECT);
 104   JavaCalls::call_static(&result,
 105                          KlassHandle(THREAD, WK_KLASS(ClassLoader_klass)),
 106                          vmSymbols::getSystemClassLoader_name(),
 107                          vmSymbols::void_classloader_signature(),
 108                          CHECK);
 109 
 110   _java_system_loader = (oop)result.get_jobject();
 111 }
 112 
 113 
 114 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, TRAPS) {
 115   if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
 116   return ClassLoaderDataGraph::find_or_create(class_loader, CHECK_NULL);
 117 }
 118 
 119 // ----------------------------------------------------------------------------
 120 // debugging
 121 
 122 #ifdef ASSERT
 123 
 124 // return true if class_name contains no '.' (internal format is '/')
 125 bool SystemDictionary::is_internal_format(Symbol* class_name) {
 126   if (class_name != NULL) {
 127     ResourceMark rm;
 128     char* name = class_name->as_C_string();
 129     return strchr(name, '.') == NULL;
 130   } else {
 131     return true;
 132   }
 133 }
 134 
 135 #endif
 136 
 137 // ----------------------------------------------------------------------------
 138 // Parallel class loading check
 139 
 140 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
 141   if (UnsyncloadClass || class_loader.is_null()) return true;
 142   if (AlwaysLockClassLoader) return false;
 143   return java_lang_ClassLoader::parallelCapable(class_loader());
 144 }
 145 // ----------------------------------------------------------------------------
 146 // ParallelDefineClass flag does not apply to bootclass loader
 147 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
 148    if (class_loader.is_null()) return false;
 149    if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
 150      return true;
 151    }
 152    return false;
 153 }
 154 
 155 /**
 156  * Returns true if the passed class loader is the extension class loader.
 157  */
 158 bool SystemDictionary::is_ext_class_loader(Handle class_loader) {
 159   if (class_loader.is_null()) {
 160     return false;
 161   }
 162   return (class_loader->klass()->name() == vmSymbols::sun_misc_Launcher_ExtClassLoader());
 163 }
 164 
 165 // ----------------------------------------------------------------------------
 166 // Resolving of classes
 167 
 168 // Forwards to resolve_or_null
 169 
 170 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
 171   Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
 172   if (HAS_PENDING_EXCEPTION || klass == NULL) {
 173     KlassHandle k_h(THREAD, klass);
 174     // can return a null klass
 175     klass = handle_resolution_exception(class_name, class_loader, protection_domain, throw_error, k_h, THREAD);
 176   }
 177   return klass;
 178 }
 179 
 180 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, KlassHandle klass_h, TRAPS) {
 181   if (HAS_PENDING_EXCEPTION) {
 182     // If we have a pending exception we forward it to the caller, unless throw_error is true,
 183     // in which case we have to check whether the pending exception is a ClassNotFoundException,
 184     // and if so convert it to a NoClassDefFoundError
 185     // And chain the original ClassNotFoundException
 186     if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
 187       ResourceMark rm(THREAD);
 188       assert(klass_h() == NULL, "Should not have result with exception pending");
 189       Handle e(THREAD, PENDING_EXCEPTION);
 190       CLEAR_PENDING_EXCEPTION;
 191       THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
 192     } else {
 193       return NULL;
 194     }
 195   }
 196   // Class not found, throw appropriate error or exception depending on value of throw_error
 197   if (klass_h() == NULL) {
 198     ResourceMark rm(THREAD);
 199     if (throw_error) {
 200       THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
 201     } else {
 202       THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
 203     }
 204   }
 205   return (Klass*)klass_h();
 206 }
 207 
 208 
 209 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
 210                                            bool throw_error, TRAPS)
 211 {
 212   return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
 213 }
 214 
 215 
 216 // Forwards to resolve_instance_class_or_null
 217 
 218 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
 219   assert(!THREAD->is_Compiler_thread(),
 220          err_msg("can not load classes with compiler thread: class=%s, classloader=%s",
 221                  class_name->as_C_string(),
 222                  class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string()));
 223   if (FieldType::is_array(class_name)) {
 224     return resolve_array_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
 225   } else if (FieldType::is_obj(class_name)) {
 226     ResourceMark rm(THREAD);
 227     // Ignore wrapping L and ;.
 228     TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
 229                                    class_name->utf8_length() - 2, CHECK_NULL);
 230     return resolve_instance_class_or_null(name, class_loader, protection_domain, CHECK_NULL);
 231   } else {
 232     return resolve_instance_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
 233   }
 234 }
 235 
 236 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
 237   return resolve_or_null(class_name, Handle(), Handle(), THREAD);
 238 }
 239 
 240 // Forwards to resolve_instance_class_or_null
 241 
 242 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
 243                                                        Handle class_loader,
 244                                                        Handle protection_domain,
 245                                                        TRAPS) {
 246   assert(FieldType::is_array(class_name), "must be array");
 247   Klass* k = NULL;
 248   FieldArrayInfo fd;
 249   // dimension and object_key in FieldArrayInfo are assigned as a side-effect
 250   // of this call
 251   BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
 252   if (t == T_OBJECT) {
 253     // naked oop "k" is OK here -- we assign back into it
 254     k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
 255                                                          class_loader,
 256                                                          protection_domain,
 257                                                          CHECK_NULL);
 258     if (k != NULL) {
 259       k = k->array_klass(fd.dimension(), CHECK_NULL);
 260     }
 261   } else {
 262     k = Universe::typeArrayKlassObj(t);
 263     k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
 264   }
 265   return k;
 266 }
 267 
 268 
 269 // Must be called for any super-class or super-interface resolution
 270 // during class definition to allow class circularity checking
 271 // super-interface callers:
 272 //    parse_interfaces - for defineClass & jvmtiRedefineClasses
 273 // super-class callers:
 274 //   ClassFileParser - for defineClass & jvmtiRedefineClasses
 275 //   load_shared_class - while loading a class from shared archive
 276 //   resolve_instance_class_or_null:
 277 //     via: handle_parallel_super_load
 278 //      when resolving a class that has an existing placeholder with
 279 //      a saved superclass [i.e. a defineClass is currently in progress]
 280 //      if another thread is trying to resolve the class, it must do
 281 //      super-class checks on its own thread to catch class circularity
 282 // This last call is critical in class circularity checking for cases
 283 // where classloading is delegated to different threads and the
 284 // classloader lock is released.
 285 // Take the case: Base->Super->Base
 286 //   1. If thread T1 tries to do a defineClass of class Base
 287 //    resolve_super_or_fail creates placeholder: T1, Base (super Super)
 288 //   2. resolve_instance_class_or_null does not find SD or placeholder for Super
 289 //    so it tries to load Super
 290 //   3. If we load the class internally, or user classloader uses same thread
 291 //      loadClassFromxxx or defineClass via parseClassFile Super ...
 292 //      3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
 293 //      3.3 resolve_instance_class_or_null Base, finds placeholder for Base
 294 //      3.4 calls resolve_super_or_fail Base
 295 //      3.5 finds T1,Base -> throws class circularity
 296 //OR 4. If T2 tries to resolve Super via defineClass Super ...
 297 //      4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
 298 //      4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
 299 //      4.3 calls resolve_super_or_fail Super in parallel on own thread T2
 300 //      4.4 finds T2, Super -> throws class circularity
 301 // Must be called, even if superclass is null, since this is
 302 // where the placeholder entry is created which claims this
 303 // thread is loading this class/classloader.
 304 Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
 305                                                  Symbol* class_name,
 306                                                  Handle class_loader,
 307                                                  Handle protection_domain,
 308                                                  bool is_superclass,
 309                                                  TRAPS) {
 310   // Double-check, if child class is already loaded, just return super-class,interface
 311   // Don't add a placedholder if already loaded, i.e. already in system dictionary
 312   // Make sure there's a placeholder for the *child* before resolving.
 313   // Used as a claim that this thread is currently loading superclass/classloader
 314   // Used here for ClassCircularity checks and also for heap verification
 315   // (every InstanceKlass in the heap needs to be in the system dictionary
 316   // or have a placeholder).
 317   // Must check ClassCircularity before checking if super class is already loaded
 318   //
 319   // We might not already have a placeholder if this child_name was
 320   // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
 321   // the name of the class might not be known until the stream is actually
 322   // parsed.
 323   // Bugs 4643874, 4715493
 324   // compute_hash can have a safepoint
 325 
 326   ClassLoaderData* loader_data = class_loader_data(class_loader);
 327   unsigned int d_hash = dictionary()->compute_hash(child_name, loader_data);
 328   int d_index = dictionary()->hash_to_index(d_hash);
 329   unsigned int p_hash = placeholders()->compute_hash(child_name, loader_data);
 330   int p_index = placeholders()->hash_to_index(p_hash);
 331   // can't throw error holding a lock
 332   bool child_already_loaded = false;
 333   bool throw_circularity_error = false;
 334   {
 335     MutexLocker mu(SystemDictionary_lock, THREAD);
 336     Klass* childk = find_class(d_index, d_hash, child_name, loader_data);
 337     Klass* quicksuperk;
 338     // to support // loading: if child done loading, just return superclass
 339     // if class_name, & class_loader don't match:
 340     // if initial define, SD update will give LinkageError
 341     // if redefine: compare_class_versions will give HIERARCHY_CHANGED
 342     // so we don't throw an exception here.
 343     // see: nsk redefclass014 & java.lang.instrument Instrument032
 344     if ((childk != NULL ) && (is_superclass) &&
 345        ((quicksuperk = InstanceKlass::cast(childk)->super()) != NULL) &&
 346 
 347          ((quicksuperk->name() == class_name) &&
 348             (quicksuperk->class_loader()  == class_loader()))) {
 349            return quicksuperk;
 350     } else {
 351       PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
 352       if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
 353           throw_circularity_error = true;
 354       }
 355     }
 356     if (!throw_circularity_error) {
 357       PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
 358     }
 359   }
 360   if (throw_circularity_error) {
 361       ResourceMark rm(THREAD);
 362       THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
 363   }
 364 
 365 // java.lang.Object should have been found above
 366   assert(class_name != NULL, "null super class for resolving");
 367   // Resolve the super class or interface, check results on return
 368   Klass* superk = SystemDictionary::resolve_or_null(class_name,
 369                                                  class_loader,
 370                                                  protection_domain,
 371                                                  THREAD);
 372 
 373   KlassHandle superk_h(THREAD, superk);
 374 
 375   // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
 376   // It is no longer necessary to keep the placeholder table alive until update_dictionary
 377   // or error. GC used to walk the placeholder table as strong roots.
 378   // The instanceKlass is kept alive because the class loader is on the stack,
 379   // which keeps the loader_data alive, as well as all instanceKlasses in
 380   // the loader_data. parseClassFile adds the instanceKlass to loader_data.
 381   {
 382     MutexLocker mu(SystemDictionary_lock, THREAD);
 383     placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
 384     SystemDictionary_lock->notify_all();
 385   }
 386   if (HAS_PENDING_EXCEPTION || superk_h() == NULL) {
 387     // can null superk
 388     superk_h = KlassHandle(THREAD, handle_resolution_exception(class_name, class_loader, protection_domain, true, superk_h, THREAD));
 389   }
 390 
 391   return superk_h();
 392 }
 393 
 394 void SystemDictionary::validate_protection_domain(instanceKlassHandle klass,
 395                                                   Handle class_loader,
 396                                                   Handle protection_domain,
 397                                                   TRAPS) {
 398   if(!has_checkPackageAccess()) return;
 399 
 400   // Now we have to call back to java to check if the initating class has access
 401   JavaValue result(T_VOID);
 402   if (TraceProtectionDomainVerification) {
 403     // Print out trace information
 404     tty->print_cr("Checking package access");
 405     tty->print(" - class loader:      "); class_loader()->print_value_on(tty);      tty->cr();
 406     tty->print(" - protection domain: "); protection_domain()->print_value_on(tty); tty->cr();
 407     tty->print(" - loading:           "); klass()->print_value_on(tty);             tty->cr();
 408   }
 409 
 410   KlassHandle system_loader(THREAD, SystemDictionary::ClassLoader_klass());
 411   JavaCalls::call_special(&result,
 412                          class_loader,
 413                          system_loader,
 414                          vmSymbols::checkPackageAccess_name(),
 415                          vmSymbols::class_protectiondomain_signature(),
 416                          Handle(THREAD, klass->java_mirror()),
 417                          protection_domain,
 418                          THREAD);
 419 
 420   if (TraceProtectionDomainVerification) {
 421     if (HAS_PENDING_EXCEPTION) {
 422       tty->print_cr(" -> DENIED !!!!!!!!!!!!!!!!!!!!!");
 423     } else {
 424      tty->print_cr(" -> granted");
 425     }
 426     tty->cr();
 427   }
 428 
 429   if (HAS_PENDING_EXCEPTION) return;
 430 
 431   // If no exception has been thrown, we have validated the protection domain
 432   // Insert the protection domain of the initiating class into the set.
 433   {
 434     // We recalculate the entry here -- we've called out to java since
 435     // the last time it was calculated.
 436     ClassLoaderData* loader_data = class_loader_data(class_loader);
 437 
 438     Symbol*  kn = klass->name();
 439     unsigned int d_hash = dictionary()->compute_hash(kn, loader_data);
 440     int d_index = dictionary()->hash_to_index(d_hash);
 441 
 442     MutexLocker mu(SystemDictionary_lock, THREAD);
 443     {
 444       // Note that we have an entry, and entries can be deleted only during GC,
 445       // so we cannot allow GC to occur while we're holding this entry.
 446 
 447       // We're using a No_Safepoint_Verifier to catch any place where we
 448       // might potentially do a GC at all.
 449       // Dictionary::do_unloading() asserts that classes in SD are only
 450       // unloaded at a safepoint. Anonymous classes are not in SD.
 451       No_Safepoint_Verifier nosafepoint;
 452       dictionary()->add_protection_domain(d_index, d_hash, klass, loader_data,
 453                                           protection_domain, THREAD);
 454     }
 455   }
 456 }
 457 
 458 // We only get here if this thread finds that another thread
 459 // has already claimed the placeholder token for the current operation,
 460 // but that other thread either never owned or gave up the
 461 // object lock
 462 // Waits on SystemDictionary_lock to indicate placeholder table updated
 463 // On return, caller must recheck placeholder table state
 464 //
 465 // We only get here if
 466 //  1) custom classLoader, i.e. not bootstrap classloader
 467 //  2) UnsyncloadClass not set
 468 //  3) custom classLoader has broken the class loader objectLock
 469 //     so another thread got here in parallel
 470 //
 471 // lockObject must be held.
 472 // Complicated dance due to lock ordering:
 473 // Must first release the classloader object lock to
 474 // allow initial definer to complete the class definition
 475 // and to avoid deadlock
 476 // Reclaim classloader lock object with same original recursion count
 477 // Must release SystemDictionary_lock after notify, since
 478 // class loader lock must be claimed before SystemDictionary_lock
 479 // to prevent deadlocks
 480 //
 481 // The notify allows applications that did an untimed wait() on
 482 // the classloader object lock to not hang.
 483 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
 484   assert_lock_strong(SystemDictionary_lock);
 485 
 486   bool calledholdinglock
 487       = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
 488   assert(calledholdinglock,"must hold lock for notify");
 489   assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
 490   ObjectSynchronizer::notifyall(lockObject, THREAD);
 491   intptr_t recursions =  ObjectSynchronizer::complete_exit(lockObject, THREAD);
 492   SystemDictionary_lock->wait();
 493   SystemDictionary_lock->unlock();
 494   ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
 495   SystemDictionary_lock->lock();
 496 }
 497 
 498 // If the class in is in the placeholder table, class loading is in progress
 499 // For cases where the application changes threads to load classes, it
 500 // is critical to ClassCircularity detection that we try loading
 501 // the superclass on the same thread internally, so we do parallel
 502 // super class loading here.
 503 // This also is critical in cases where the original thread gets stalled
 504 // even in non-circularity situations.
 505 // Note: must call resolve_super_or_fail even if null super -
 506 // to force placeholder entry creation for this class for circularity detection
 507 // Caller must check for pending exception
 508 // Returns non-null Klass* if other thread has completed load
 509 // and we are done,
 510 // If return null Klass* and no pending exception, the caller must load the class
 511 instanceKlassHandle SystemDictionary::handle_parallel_super_load(
 512     Symbol* name, Symbol* superclassname, Handle class_loader,
 513     Handle protection_domain, Handle lockObject, TRAPS) {
 514 
 515   instanceKlassHandle nh = instanceKlassHandle(); // null Handle
 516   ClassLoaderData* loader_data = class_loader_data(class_loader);
 517   unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
 518   int d_index = dictionary()->hash_to_index(d_hash);
 519   unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
 520   int p_index = placeholders()->hash_to_index(p_hash);
 521 
 522   // superk is not used, resolve_super called for circularity check only
 523   // This code is reached in two situations. One if this thread
 524   // is loading the same class twice (e.g. ClassCircularity, or
 525   // java.lang.instrument).
 526   // The second is if another thread started the resolve_super first
 527   // and has not yet finished.
 528   // In both cases the original caller will clean up the placeholder
 529   // entry on error.
 530   Klass* superk = SystemDictionary::resolve_super_or_fail(name,
 531                                                           superclassname,
 532                                                           class_loader,
 533                                                           protection_domain,
 534                                                           true,
 535                                                           CHECK_(nh));
 536 
 537   // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
 538   // Serial class loaders and bootstrap classloader do wait for superclass loads
 539  if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
 540     MutexLocker mu(SystemDictionary_lock, THREAD);
 541     // Check if classloading completed while we were loading superclass or waiting
 542     Klass* check = find_class(d_index, d_hash, name, loader_data);
 543     if (check != NULL) {
 544       // Klass is already loaded, so just return it
 545       return(instanceKlassHandle(THREAD, check));
 546     } else {
 547       return nh;
 548     }
 549   }
 550 
 551   // must loop to both handle other placeholder updates
 552   // and spurious notifications
 553   bool super_load_in_progress = true;
 554   PlaceholderEntry* placeholder;
 555   while (super_load_in_progress) {
 556     MutexLocker mu(SystemDictionary_lock, THREAD);
 557     // Check if classloading completed while we were loading superclass or waiting
 558     Klass* check = find_class(d_index, d_hash, name, loader_data);
 559     if (check != NULL) {
 560       // Klass is already loaded, so just return it
 561       return(instanceKlassHandle(THREAD, check));
 562     } else {
 563       placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
 564       if (placeholder && placeholder->super_load_in_progress() ){
 565         // Before UnsyncloadClass:
 566         // We only get here if the application has released the
 567         // classloader lock when another thread was in the middle of loading a
 568         // superclass/superinterface for this class, and now
 569         // this thread is also trying to load this class.
 570         // To minimize surprises, the first thread that started to
 571         // load a class should be the one to complete the loading
 572         // with the classfile it initially expected.
 573         // This logic has the current thread wait once it has done
 574         // all the superclass/superinterface loading it can, until
 575         // the original thread completes the class loading or fails
 576         // If it completes we will use the resulting InstanceKlass
 577         // which we will find below in the systemDictionary.
 578         // We also get here for parallel bootstrap classloader
 579         if (class_loader.is_null()) {
 580           SystemDictionary_lock->wait();
 581         } else {
 582           double_lock_wait(lockObject, THREAD);
 583         }
 584       } else {
 585         // If not in SD and not in PH, other thread's load must have failed
 586         super_load_in_progress = false;
 587       }
 588     }
 589   }
 590   return (nh);
 591 }
 592 
 593 
 594 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
 595                                                         Handle class_loader,
 596                                                         Handle protection_domain,
 597                                                         TRAPS) {
 598   assert(name != NULL && !FieldType::is_array(name) &&
 599          !FieldType::is_obj(name), "invalid class name");
 600 
 601   TracingTime class_load_start_time = Tracing::time();
 602 
 603   // UseNewReflection
 604   // Fix for 4474172; see evaluation for more details
 605   class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
 606   ClassLoaderData *loader_data = register_loader(class_loader, CHECK_NULL);
 607 
 608   // Do lookup to see if class already exist and the protection domain
 609   // has the right access
 610   // This call uses find which checks protection domain already matches
 611   // All subsequent calls use find_class, and set has_loaded_class so that
 612   // before we return a result we call out to java to check for valid protection domain
 613   // to allow returning the Klass* and add it to the pd_set if it is valid
 614   unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
 615   int d_index = dictionary()->hash_to_index(d_hash);
 616   Klass* probe = dictionary()->find(d_index, d_hash, name, loader_data,
 617                                       protection_domain, THREAD);
 618   if (probe != NULL) return probe;
 619 
 620 
 621   // Non-bootstrap class loaders will call out to class loader and
 622   // define via jvm/jni_DefineClass which will acquire the
 623   // class loader object lock to protect against multiple threads
 624   // defining the class in parallel by accident.
 625   // This lock must be acquired here so the waiter will find
 626   // any successful result in the SystemDictionary and not attempt
 627   // the define
 628   // ParallelCapable Classloaders and the bootstrap classloader,
 629   // or all classloaders with UnsyncloadClass do not acquire lock here
 630   bool DoObjectLock = true;
 631   if (is_parallelCapable(class_loader)) {
 632     DoObjectLock = false;
 633   }
 634 
 635   unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
 636   int p_index = placeholders()->hash_to_index(p_hash);
 637 
 638   // Class is not in SystemDictionary so we have to do loading.
 639   // Make sure we are synchronized on the class loader before we proceed
 640   Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
 641   check_loader_lock_contention(lockObject, THREAD);
 642   ObjectLocker ol(lockObject, THREAD, DoObjectLock);
 643 
 644   // Check again (after locking) if class already exist in SystemDictionary
 645   bool class_has_been_loaded   = false;
 646   bool super_load_in_progress  = false;
 647   bool havesupername = false;
 648   instanceKlassHandle k;
 649   PlaceholderEntry* placeholder;
 650   Symbol* superclassname = NULL;
 651 
 652   {
 653     MutexLocker mu(SystemDictionary_lock, THREAD);
 654     Klass* check = find_class(d_index, d_hash, name, loader_data);
 655     if (check != NULL) {
 656       // Klass is already loaded, so just return it
 657       class_has_been_loaded = true;
 658       k = instanceKlassHandle(THREAD, check);
 659     } else {
 660       placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
 661       if (placeholder && placeholder->super_load_in_progress()) {
 662          super_load_in_progress = true;
 663          if (placeholder->havesupername() == true) {
 664            superclassname = placeholder->supername();
 665            havesupername = true;
 666          }
 667       }
 668     }
 669   }
 670 
 671   // If the class is in the placeholder table, class loading is in progress
 672   if (super_load_in_progress && havesupername==true) {
 673     k = SystemDictionary::handle_parallel_super_load(name, superclassname,
 674         class_loader, protection_domain, lockObject, THREAD);
 675     if (HAS_PENDING_EXCEPTION) {
 676       return NULL;
 677     }
 678     if (!k.is_null()) {
 679       class_has_been_loaded = true;
 680     }
 681   }
 682 
 683   bool throw_circularity_error = false;
 684   if (!class_has_been_loaded) {
 685     bool load_instance_added = false;
 686 
 687     // add placeholder entry to record loading instance class
 688     // Five cases:
 689     // All cases need to prevent modifying bootclasssearchpath
 690     // in parallel with a classload of same classname
 691     // Redefineclasses uses existence of the placeholder for the duration
 692     // of the class load to prevent concurrent redefinition of not completely
 693     // defined classes.
 694     // case 1. traditional classloaders that rely on the classloader object lock
 695     //   - no other need for LOAD_INSTANCE
 696     // case 2. traditional classloaders that break the classloader object lock
 697     //    as a deadlock workaround. Detection of this case requires that
 698     //    this check is done while holding the classloader object lock,
 699     //    and that lock is still held when calling classloader's loadClass.
 700     //    For these classloaders, we ensure that the first requestor
 701     //    completes the load and other requestors wait for completion.
 702     // case 3. UnsyncloadClass - don't use objectLocker
 703     //    With this flag, we allow parallel classloading of a
 704     //    class/classloader pair
 705     // case4. Bootstrap classloader - don't own objectLocker
 706     //    This classloader supports parallelism at the classloader level,
 707     //    but only allows a single load of a class/classloader pair.
 708     //    No performance benefit and no deadlock issues.
 709     // case 5. parallelCapable user level classloaders - without objectLocker
 710     //    Allow parallel classloading of a class/classloader pair
 711 
 712     {
 713       MutexLocker mu(SystemDictionary_lock, THREAD);
 714       if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
 715         PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
 716         if (oldprobe) {
 717           // only need check_seen_thread once, not on each loop
 718           // 6341374 java/lang/Instrument with -Xcomp
 719           if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
 720             throw_circularity_error = true;
 721           } else {
 722             // case 1: traditional: should never see load_in_progress.
 723             while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
 724 
 725               // case 4: bootstrap classloader: prevent futile classloading,
 726               // wait on first requestor
 727               if (class_loader.is_null()) {
 728                 SystemDictionary_lock->wait();
 729               } else {
 730               // case 2: traditional with broken classloader lock. wait on first
 731               // requestor.
 732                 double_lock_wait(lockObject, THREAD);
 733               }
 734               // Check if classloading completed while we were waiting
 735               Klass* check = find_class(d_index, d_hash, name, loader_data);
 736               if (check != NULL) {
 737                 // Klass is already loaded, so just return it
 738                 k = instanceKlassHandle(THREAD, check);
 739                 class_has_been_loaded = true;
 740               }
 741               // check if other thread failed to load and cleaned up
 742               oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
 743             }
 744           }
 745         }
 746       }
 747       // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
 748       // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try
 749       // LOAD_INSTANCE in parallel
 750 
 751       if (!throw_circularity_error && !class_has_been_loaded) {
 752         PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
 753         load_instance_added = true;
 754         // For class loaders that do not acquire the classloader object lock,
 755         // if they did not catch another thread holding LOAD_INSTANCE,
 756         // need a check analogous to the acquire ObjectLocker/find_class
 757         // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
 758         // one final check if the load has already completed
 759         // class loaders holding the ObjectLock shouldn't find the class here
 760         Klass* check = find_class(d_index, d_hash, name, loader_data);
 761         if (check != NULL) {
 762         // Klass is already loaded, so return it after checking/adding protection domain
 763           k = instanceKlassHandle(THREAD, check);
 764           class_has_been_loaded = true;
 765         }
 766       }
 767     }
 768 
 769     // must throw error outside of owning lock
 770     if (throw_circularity_error) {
 771       assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
 772       ResourceMark rm(THREAD);
 773       THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
 774     }
 775 
 776     if (!class_has_been_loaded) {
 777 
 778       // Do actual loading
 779       k = load_instance_class(name, class_loader, THREAD);
 780 
 781       // For UnsyncloadClass only
 782       // If they got a linkageError, check if a parallel class load succeeded.
 783       // If it did, then for bytecode resolution the specification requires
 784       // that we return the same result we did for the other thread, i.e. the
 785       // successfully loaded InstanceKlass
 786       // Should not get here for classloaders that support parallelism
 787       // with the new cleaner mechanism, even with AllowParallelDefineClass
 788       // Bootstrap goes through here to allow for an extra guarantee check
 789       if (UnsyncloadClass || (class_loader.is_null())) {
 790         if (k.is_null() && HAS_PENDING_EXCEPTION
 791           && PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass())) {
 792           MutexLocker mu(SystemDictionary_lock, THREAD);
 793           Klass* check = find_class(d_index, d_hash, name, loader_data);
 794           if (check != NULL) {
 795             // Klass is already loaded, so just use it
 796             k = instanceKlassHandle(THREAD, check);
 797             CLEAR_PENDING_EXCEPTION;
 798             guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?");
 799           }
 800         }
 801       }
 802 
 803       // If everything was OK (no exceptions, no null return value), and
 804       // class_loader is NOT the defining loader, do a little more bookkeeping.
 805       if (!HAS_PENDING_EXCEPTION && !k.is_null() &&
 806         k->class_loader() != class_loader()) {
 807 
 808         check_constraints(d_index, d_hash, k, class_loader, false, THREAD);
 809 
 810         // Need to check for a PENDING_EXCEPTION again; check_constraints
 811         // can throw and doesn't use the CHECK macro.
 812         if (!HAS_PENDING_EXCEPTION) {
 813           { // Grabbing the Compile_lock prevents systemDictionary updates
 814             // during compilations.
 815             MutexLocker mu(Compile_lock, THREAD);
 816             update_dictionary(d_index, d_hash, p_index, p_hash,
 817                               k, class_loader, THREAD);
 818           }
 819 
 820           if (JvmtiExport::should_post_class_load()) {
 821             Thread *thread = THREAD;
 822             assert(thread->is_Java_thread(), "thread->is_Java_thread()");
 823             JvmtiExport::post_class_load((JavaThread *) thread, k());
 824           }
 825         }
 826       }
 827     } // load_instance_class loop
 828 
 829     if (HAS_PENDING_EXCEPTION) {
 830       // An exception, such as OOM could have happened at various places inside
 831       // load_instance_class. We might have partially initialized a shared class
 832       // and need to clean it up.
 833       if (class_loader.is_null()) {
 834         // In some cases k may be null. Let's find the shared class again.
 835         instanceKlassHandle ik(THREAD, find_shared_class(name));
 836         if (ik.not_null()) {
 837           if (ik->class_loader_data() == NULL) {
 838             // We didn't go as far as Klass::restore_unshareable_info(),
 839             // so nothing to clean up.
 840           } else {
 841             Klass *kk;
 842             {
 843               MutexLocker mu(SystemDictionary_lock, THREAD);
 844               kk = find_class(d_index, d_hash, name, ik->class_loader_data());
 845             }
 846             if (kk != NULL) {
 847               // No clean up is needed if the shared class has been entered
 848               // into system dictionary, as load_shared_class() won't be called
 849               // again.
 850             } else {
 851               // This must be done outside of the SystemDictionary_lock to
 852               // avoid deadlock.
 853               //
 854               // Note that Klass::restore_unshareable_info (called via
 855               // load_instance_class above) is also called outside
 856               // of SystemDictionary_lock. Other threads are blocked from
 857               // loading this class because they are waiting on the
 858               // SystemDictionary_lock until this thread removes
 859               // the placeholder below.
 860               //
 861               // This need to be re-thought when parallel-capable non-boot
 862               // classloaders are supported by CDS (today they're not).
 863               clean_up_shared_class(ik, class_loader, THREAD);
 864             }
 865           }
 866         }
 867       }
 868     }
 869 
 870     if (load_instance_added == true) {
 871       // clean up placeholder entries for LOAD_INSTANCE success or error
 872       // This brackets the SystemDictionary updates for both defining
 873       // and initiating loaders
 874       MutexLocker mu(SystemDictionary_lock, THREAD);
 875       placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
 876       SystemDictionary_lock->notify_all();
 877     }
 878   }
 879 
 880   if (HAS_PENDING_EXCEPTION || k.is_null()) {
 881     return NULL;
 882   }
 883 
 884   post_class_load_event(class_load_start_time, k, class_loader);
 885 
 886 #ifdef ASSERT
 887   {
 888     ClassLoaderData* loader_data = k->class_loader_data();
 889     MutexLocker mu(SystemDictionary_lock, THREAD);
 890     Klass* kk = find_class(name, loader_data);
 891     assert(kk == k(), "should be present in dictionary");
 892   }
 893 #endif
 894 
 895   // return if the protection domain in NULL
 896   if (protection_domain() == NULL) return k();
 897 
 898   // Check the protection domain has the right access
 899   {
 900     MutexLocker mu(SystemDictionary_lock, THREAD);
 901     // Note that we have an entry, and entries can be deleted only during GC,
 902     // so we cannot allow GC to occur while we're holding this entry.
 903     // We're using a No_Safepoint_Verifier to catch any place where we
 904     // might potentially do a GC at all.
 905     // Dictionary::do_unloading() asserts that classes in SD are only
 906     // unloaded at a safepoint. Anonymous classes are not in SD.
 907     No_Safepoint_Verifier nosafepoint;
 908     if (dictionary()->is_valid_protection_domain(d_index, d_hash, name,
 909                                                  loader_data,
 910                                                  protection_domain)) {
 911       return k();
 912     }
 913   }
 914 
 915   // Verify protection domain. If it fails an exception is thrown
 916   validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
 917 
 918   return k();
 919 }
 920 
 921 
 922 // This routine does not lock the system dictionary.
 923 //
 924 // Since readers don't hold a lock, we must make sure that system
 925 // dictionary entries are only removed at a safepoint (when only one
 926 // thread is running), and are added to in a safe way (all links must
 927 // be updated in an MT-safe manner).
 928 //
 929 // Callers should be aware that an entry could be added just after
 930 // _dictionary->bucket(index) is read here, so the caller will not see
 931 // the new entry.
 932 
 933 Klass* SystemDictionary::find(Symbol* class_name,
 934                               Handle class_loader,
 935                               Handle protection_domain,
 936                               TRAPS) {
 937 
 938   // UseNewReflection
 939   // The result of this call should be consistent with the result
 940   // of the call to resolve_instance_class_or_null().
 941   // See evaluation 6790209 and 4474172 for more details.
 942   class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
 943   ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
 944 
 945   if (loader_data == NULL) {
 946     // If the ClassLoaderData has not been setup,
 947     // then the class loader has no entries in the dictionary.
 948     return NULL;
 949   }
 950 
 951   unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
 952   int d_index = dictionary()->hash_to_index(d_hash);
 953 
 954   {
 955     // Note that we have an entry, and entries can be deleted only during GC,
 956     // so we cannot allow GC to occur while we're holding this entry.
 957     // We're using a No_Safepoint_Verifier to catch any place where we
 958     // might potentially do a GC at all.
 959     // Dictionary::do_unloading() asserts that classes in SD are only
 960     // unloaded at a safepoint. Anonymous classes are not in SD.
 961     No_Safepoint_Verifier nosafepoint;
 962     return dictionary()->find(d_index, d_hash, class_name, loader_data,
 963                               protection_domain, THREAD);
 964   }
 965 }
 966 
 967 
 968 // Look for a loaded instance or array klass by name.  Do not do any loading.
 969 // return NULL in case of error.
 970 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
 971                                                       Handle class_loader,
 972                                                       Handle protection_domain,
 973                                                       TRAPS) {
 974   Klass* k = NULL;
 975   assert(class_name != NULL, "class name must be non NULL");
 976 
 977   if (FieldType::is_array(class_name)) {
 978     // The name refers to an array.  Parse the name.
 979     // dimension and object_key in FieldArrayInfo are assigned as a
 980     // side-effect of this call
 981     FieldArrayInfo fd;
 982     BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
 983     if (t != T_OBJECT) {
 984       k = Universe::typeArrayKlassObj(t);
 985     } else {
 986       k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
 987     }
 988     if (k != NULL) {
 989       k = k->array_klass_or_null(fd.dimension());
 990     }
 991   } else {
 992     k = find(class_name, class_loader, protection_domain, THREAD);
 993   }
 994   return k;
 995 }
 996 
 997 // Note: this method is much like resolve_from_stream, but
 998 // updates no supplemental data structures.
 999 // TODO consolidate the two methods with a helper routine?
1000 Klass* SystemDictionary::parse_stream(Symbol* class_name,
1001                                       Handle class_loader,
1002                                       Handle protection_domain,
1003                                       ClassFileStream* st,
1004                                       KlassHandle host_klass,
1005                                       GrowableArray<Handle>* cp_patches,
1006                                       TRAPS) {
1007   TempNewSymbol parsed_name = NULL;
1008 
1009   TracingTime class_load_start_time = Tracing::time();
1010 
1011   ClassLoaderData* loader_data;
1012   if (host_klass.not_null()) {
1013     // Create a new CLD for anonymous class, that uses the same class loader
1014     // as the host_klass
1015     assert(EnableInvokeDynamic, "");
1016     guarantee(host_klass->class_loader() == class_loader(), "should be the same");
1017     loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader(), CHECK_NULL);
1018     loader_data->record_dependency(host_klass(), CHECK_NULL);
1019   } else {
1020     loader_data = ClassLoaderData::class_loader_data(class_loader());
1021   }
1022 
1023   // Parse the stream. Note that we do this even though this klass might
1024   // already be present in the SystemDictionary, otherwise we would not
1025   // throw potential ClassFormatErrors.
1026   //
1027   // Note: "name" is updated.
1028 
1029   instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
1030                                                              loader_data,
1031                                                              protection_domain,
1032                                                              host_klass,
1033                                                              cp_patches,
1034                                                              parsed_name,
1035                                                              true,
1036                                                              THREAD);
1037 
1038 
1039   if (host_klass.not_null() && k.not_null()) {
1040     assert(EnableInvokeDynamic, "");
1041     k->set_host_klass(host_klass());
1042     // If it's anonymous, initialize it now, since nobody else will.
1043 
1044     {
1045       MutexLocker mu_r(Compile_lock, THREAD);
1046 
1047       // Add to class hierarchy, initialize vtables, and do possible
1048       // deoptimizations.
1049       add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1050 
1051       // But, do not add to system dictionary.
1052     }
1053 
1054     // Rewrite and patch constant pool here.
1055     k->link_class(CHECK_NULL);
1056     if (cp_patches != NULL) {
1057       k->constants()->patch_resolved_references(cp_patches);
1058     }
1059     k->eager_initialize(CHECK_NULL);
1060 
1061     // notify jvmti
1062     if (JvmtiExport::should_post_class_load()) {
1063         assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1064         JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1065     }
1066 
1067     post_class_load_event(class_load_start_time, k, class_loader);
1068   }
1069   assert(host_klass.not_null() || cp_patches == NULL,
1070          "cp_patches only found with host_klass");
1071 
1072   return k();
1073 }
1074 
1075 // Add a klass to the system from a stream (called by jni_DefineClass and
1076 // JVM_DefineClass).
1077 // Note: class_name can be NULL. In that case we do not know the name of
1078 // the class until we have parsed the stream.
1079 
1080 Klass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1081                                              Handle class_loader,
1082                                              Handle protection_domain,
1083                                              ClassFileStream* st,
1084                                              bool verify,
1085                                              TRAPS) {
1086 
1087   // Classloaders that support parallelism, e.g. bootstrap classloader,
1088   // or all classloaders with UnsyncloadClass do not acquire lock here
1089   bool DoObjectLock = true;
1090   if (is_parallelCapable(class_loader)) {
1091     DoObjectLock = false;
1092   }
1093 
1094   ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL);
1095 
1096   // Make sure we are synchronized on the class loader before we proceed
1097   Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1098   check_loader_lock_contention(lockObject, THREAD);
1099   ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1100 
1101   TempNewSymbol parsed_name = NULL;
1102 
1103   // Parse the stream. Note that we do this even though this klass might
1104   // already be present in the SystemDictionary, otherwise we would not
1105   // throw potential ClassFormatErrors.
1106   //
1107   // Note: "name" is updated.
1108 
1109   instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
1110                                                              loader_data,
1111                                                              protection_domain,
1112                                                              parsed_name,
1113                                                              verify,
1114                                                              THREAD);
1115 
1116   const char* pkg = "java/";
1117   if (!HAS_PENDING_EXCEPTION &&
1118       !class_loader.is_null() &&
1119       parsed_name != NULL &&
1120       !strncmp((const char*)parsed_name->bytes(), pkg, strlen(pkg))) {
1121     // It is illegal to define classes in the "java." package from
1122     // JVM_DefineClass or jni_DefineClass unless you're the bootclassloader
1123     ResourceMark rm(THREAD);
1124     char* name = parsed_name->as_C_string();
1125     char* index = strrchr(name, '/');
1126     *index = '\0'; // chop to just the package name
1127     while ((index = strchr(name, '/')) != NULL) {
1128       *index = '.'; // replace '/' with '.' in package name
1129     }
1130     const char* fmt = "Prohibited package name: %s";
1131     size_t len = strlen(fmt) + strlen(name);
1132     char* message = NEW_RESOURCE_ARRAY(char, len);
1133     jio_snprintf(message, len, fmt, name);
1134     Exceptions::_throw_msg(THREAD_AND_LOCATION,
1135       vmSymbols::java_lang_SecurityException(), message);
1136   }
1137 
1138   if (!HAS_PENDING_EXCEPTION) {
1139     assert(parsed_name != NULL, "Sanity");
1140     assert(class_name == NULL || class_name == parsed_name, "name mismatch");
1141     // Verification prevents us from creating names with dots in them, this
1142     // asserts that that's the case.
1143     assert(is_internal_format(parsed_name),
1144            "external class name format used internally");
1145 
1146     // Add class just loaded
1147     // If a class loader supports parallel classloading handle parallel define requests
1148     // find_or_define_instance_class may return a different InstanceKlass
1149     if (is_parallelCapable(class_loader)) {
1150       k = find_or_define_instance_class(class_name, class_loader, k, THREAD);
1151     } else {
1152       define_instance_class(k, THREAD);
1153     }
1154   }
1155 
1156   // Make sure we have an entry in the SystemDictionary on success
1157   debug_only( {
1158     if (!HAS_PENDING_EXCEPTION) {
1159       assert(parsed_name != NULL, "parsed_name is still null?");
1160       Symbol*  h_name    = k->name();
1161       ClassLoaderData *defining_loader_data = k->class_loader_data();
1162 
1163       MutexLocker mu(SystemDictionary_lock, THREAD);
1164 
1165       Klass* check = find_class(parsed_name, loader_data);
1166       assert(check == k(), "should be present in the dictionary");
1167 
1168       Klass* check2 = find_class(h_name, defining_loader_data);
1169       assert(check == check2, "name inconsistancy in SystemDictionary");
1170     }
1171   } );
1172 
1173   return k();
1174 }
1175 
1176 
1177 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1178                                              int number_of_entries) {
1179   assert(length == _nof_buckets * sizeof(HashtableBucket<mtClass>),
1180          "bad shared dictionary size.");
1181   _shared_dictionary = new Dictionary(_nof_buckets, t, number_of_entries);
1182 }
1183 
1184 
1185 // If there is a shared dictionary, then find the entry for the
1186 // given shared system class, if any.
1187 
1188 Klass* SystemDictionary::find_shared_class(Symbol* class_name) {
1189   if (shared_dictionary() != NULL) {
1190     unsigned int d_hash = shared_dictionary()->compute_hash(class_name, NULL);
1191     int d_index = shared_dictionary()->hash_to_index(d_hash);
1192 
1193     return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1194   } else {
1195     return NULL;
1196   }
1197 }
1198 
1199 
1200 // Load a class from the shared spaces (found through the shared system
1201 // dictionary).  Force the superclass and all interfaces to be loaded.
1202 // Update the class definition to include sibling classes and no
1203 // subclasses (yet).  [Classes in the shared space are not part of the
1204 // object hierarchy until loaded.]
1205 
1206 instanceKlassHandle SystemDictionary::load_shared_class(
1207                  Symbol* class_name, Handle class_loader, TRAPS) {
1208   instanceKlassHandle ik (THREAD, find_shared_class(class_name));
1209   return load_shared_class(ik, class_loader, THREAD);
1210 }
1211 
1212 instanceKlassHandle SystemDictionary::load_shared_class(
1213                  instanceKlassHandle ik, Handle class_loader, TRAPS) {
1214   assert(class_loader.is_null(), "non-null classloader for shared class?");
1215   if (ik.not_null()) {
1216     instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1217     Symbol*  class_name = ik->name();
1218 
1219     // Found the class, now load the superclass and interfaces.  If they
1220     // are shared, add them to the main system dictionary and reset
1221     // their hierarchy references (supers, subs, and interfaces).
1222 
1223     if (ik->super() != NULL) {
1224       Symbol*  cn = ik->super()->name();
1225       resolve_super_or_fail(class_name, cn,
1226                             class_loader, Handle(), true, CHECK_(nh));
1227     }
1228 
1229     Array<Klass*>* interfaces = ik->local_interfaces();
1230     int num_interfaces = interfaces->length();
1231     for (int index = 0; index < num_interfaces; index++) {
1232       Klass* k = interfaces->at(index);
1233 
1234       // Note: can not use InstanceKlass::cast here because
1235       // interfaces' InstanceKlass's C++ vtbls haven't been
1236       // reinitialized yet (they will be once the interface classes
1237       // are loaded)
1238       Symbol*  name  = k->name();
1239       resolve_super_or_fail(class_name, name, class_loader, Handle(), false, CHECK_(nh));
1240     }
1241 
1242     // Adjust methods to recover missing data.  They need addresses for
1243     // interpreter entry points and their default native method address
1244     // must be reset.
1245 
1246     // Updating methods must be done under a lock so multiple
1247     // threads don't update these in parallel
1248     // Shared classes are all currently loaded by the bootstrap
1249     // classloader, so this will never cause a deadlock on
1250     // a custom class loader lock.
1251 
1252     {
1253       Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1254       check_loader_lock_contention(lockObject, THREAD);
1255       ObjectLocker ol(lockObject, THREAD, true);
1256       ik->restore_unshareable_info(CHECK_(nh));
1257     }
1258 
1259     if (TraceClassLoading) {
1260       ResourceMark rm;
1261       tty->print("[Loaded %s", ik->external_name());
1262       tty->print(" from shared objects file");
1263       tty->print_cr("]");
1264     }
1265     // notify a class loaded from shared object
1266     ClassLoadingService::notify_class_loaded(InstanceKlass::cast(ik()),
1267                                              true /* shared class */);
1268   }
1269   return ik;
1270 }
1271 
1272 void SystemDictionary::clean_up_shared_class(instanceKlassHandle ik, Handle class_loader, TRAPS) {
1273   // Updating methods must be done under a lock so multiple
1274   // threads don't update these in parallel
1275   // Shared classes are all currently loaded by the bootstrap
1276   // classloader, so this will never cause a deadlock on
1277   // a custom class loader lock.
1278   {
1279     Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1280     check_loader_lock_contention(lockObject, THREAD);
1281     ObjectLocker ol(lockObject, THREAD, true);
1282     ik->remove_unshareable_info();
1283   }
1284 }
1285 
1286 instanceKlassHandle SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1287   instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1288   if (class_loader.is_null()) {
1289 
1290     // Search the shared system dictionary for classes preloaded into the
1291     // shared spaces.
1292     instanceKlassHandle k;
1293     {
1294       PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1295       k = load_shared_class(class_name, class_loader, THREAD);
1296     }
1297 
1298     if (k.is_null()) {
1299       // Use VM class loader
1300       PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1301       k = ClassLoader::load_classfile(class_name, CHECK_(nh));
1302     }
1303 
1304     // find_or_define_instance_class may return a different InstanceKlass
1305     if (!k.is_null()) {
1306       k = find_or_define_instance_class(class_name, class_loader, k, CHECK_(nh));
1307     }
1308     return k;
1309   } else {
1310     // Use user specified class loader to load class. Call loadClass operation on class_loader.
1311     ResourceMark rm(THREAD);
1312 
1313     assert(THREAD->is_Java_thread(), "must be a JavaThread");
1314     JavaThread* jt = (JavaThread*) THREAD;
1315 
1316     PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1317                                ClassLoader::perf_app_classload_selftime(),
1318                                ClassLoader::perf_app_classload_count(),
1319                                jt->get_thread_stat()->perf_recursion_counts_addr(),
1320                                jt->get_thread_stat()->perf_timers_addr(),
1321                                PerfClassTraceTime::CLASS_LOAD);
1322 
1323     Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nh));
1324     // Translate to external class name format, i.e., convert '/' chars to '.'
1325     Handle string = java_lang_String::externalize_classname(s, CHECK_(nh));
1326 
1327     JavaValue result(T_OBJECT);
1328 
1329     KlassHandle spec_klass (THREAD, SystemDictionary::ClassLoader_klass());
1330 
1331     // Call public unsynchronized loadClass(String) directly for all class loaders
1332     // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will
1333     // acquire a class-name based lock rather than the class loader object lock.
1334     // JDK < 7 already acquire the class loader lock in loadClass(String, boolean),
1335     // so the call to loadClassInternal() was not required.
1336     //
1337     // UnsyncloadClass flag means both call loadClass(String) and do
1338     // not acquire the class loader lock even for class loaders that are
1339     // not parallelCapable. This was a risky transitional
1340     // flag for diagnostic purposes only. It is risky to call
1341     // custom class loaders without synchronization.
1342     // WARNING If a custom class loader does NOT synchronizer findClass, or callers of
1343     // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field.
1344     // Do NOT assume this will be supported in future releases.
1345     //
1346     // Added MustCallLoadClassInternal in case we discover in the field
1347     // a customer that counts on this call
1348     if (MustCallLoadClassInternal && has_loadClassInternal()) {
1349       JavaCalls::call_special(&result,
1350                               class_loader,
1351                               spec_klass,
1352                               vmSymbols::loadClassInternal_name(),
1353                               vmSymbols::string_class_signature(),
1354                               string,
1355                               CHECK_(nh));
1356     } else {
1357       JavaCalls::call_virtual(&result,
1358                               class_loader,
1359                               spec_klass,
1360                               vmSymbols::loadClass_name(),
1361                               vmSymbols::string_class_signature(),
1362                               string,
1363                               CHECK_(nh));
1364     }
1365 
1366     assert(result.get_type() == T_OBJECT, "just checking");
1367     oop obj = (oop) result.get_jobject();
1368 
1369     // Primitive classes return null since forName() can not be
1370     // used to obtain any of the Class objects representing primitives or void
1371     if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1372       instanceKlassHandle k =
1373                 instanceKlassHandle(THREAD, java_lang_Class::as_Klass(obj));
1374       // For user defined Java class loaders, check that the name returned is
1375       // the same as that requested.  This check is done for the bootstrap
1376       // loader when parsing the class file.
1377       if (class_name == k->name()) {
1378         return k;
1379       }
1380     }
1381     // Class is not found or has the wrong name, return NULL
1382     return nh;
1383   }
1384 }
1385 
1386 void SystemDictionary::define_instance_class(instanceKlassHandle k, TRAPS) {
1387 
1388   ClassLoaderData* loader_data = k->class_loader_data();
1389   Handle class_loader_h(THREAD, loader_data->class_loader());
1390 
1391   for (uintx it = 0; it < GCExpandToAllocateDelayMillis; it++){}
1392 
1393  // for bootstrap and other parallel classloaders don't acquire lock,
1394  // use placeholder token
1395  // If a parallelCapable class loader calls define_instance_class instead of
1396  // find_or_define_instance_class to get here, we have a timing
1397  // hole with systemDictionary updates and check_constraints
1398  if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1399     assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1400          compute_loader_lock_object(class_loader_h, THREAD)),
1401          "define called without lock");
1402   }
1403 
1404   // Check class-loading constraints. Throw exception if violation is detected.
1405   // Grabs and releases SystemDictionary_lock
1406   // The check_constraints/find_class call and update_dictionary sequence
1407   // must be "atomic" for a specific class/classloader pair so we never
1408   // define two different instanceKlasses for that class/classloader pair.
1409   // Existing classloaders will call define_instance_class with the
1410   // classloader lock held
1411   // Parallel classloaders will call find_or_define_instance_class
1412   // which will require a token to perform the define class
1413   Symbol*  name_h = k->name();
1414   unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
1415   int d_index = dictionary()->hash_to_index(d_hash);
1416   check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK);
1417 
1418   // Register class just loaded with class loader (placed in Vector)
1419   // Note we do this before updating the dictionary, as this can
1420   // fail with an OutOfMemoryError (if it does, we will *not* put this
1421   // class in the dictionary and will not update the class hierarchy).
1422   // JVMTI FollowReferences needs to find the classes this way.
1423   if (k->class_loader() != NULL) {
1424     methodHandle m(THREAD, Universe::loader_addClass_method());
1425     JavaValue result(T_VOID);
1426     JavaCallArguments args(class_loader_h);
1427     args.push_oop(Handle(THREAD, k->java_mirror()));
1428     JavaCalls::call(&result, m, &args, CHECK);
1429   }
1430 
1431   // Add the new class. We need recompile lock during update of CHA.
1432   {
1433     unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
1434     int p_index = placeholders()->hash_to_index(p_hash);
1435 
1436     MutexLocker mu_r(Compile_lock, THREAD);
1437 
1438     // Add to class hierarchy, initialize vtables, and do possible
1439     // deoptimizations.
1440     add_to_hierarchy(k, CHECK); // No exception, but can block
1441 
1442     // Add to systemDictionary - so other classes can see it.
1443     // Grabs and releases SystemDictionary_lock
1444     update_dictionary(d_index, d_hash, p_index, p_hash,
1445                       k, class_loader_h, THREAD);
1446   }
1447   k->eager_initialize(THREAD);
1448 
1449   // notify jvmti
1450   if (JvmtiExport::should_post_class_load()) {
1451       assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1452       JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1453 
1454   }
1455 
1456 }
1457 
1458 // Support parallel classloading
1459 // All parallel class loaders, including bootstrap classloader
1460 // lock a placeholder entry for this class/class_loader pair
1461 // to allow parallel defines of different classes for this class loader
1462 // With AllowParallelDefine flag==true, in case they do not synchronize around
1463 // FindLoadedClass/DefineClass, calls, we check for parallel
1464 // loading for them, wait if a defineClass is in progress
1465 // and return the initial requestor's results
1466 // This flag does not apply to the bootstrap classloader.
1467 // With AllowParallelDefine flag==false, call through to define_instance_class
1468 // which will throw LinkageError: duplicate class definition.
1469 // False is the requested default.
1470 // For better performance, the class loaders should synchronize
1471 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1472 // potentially waste time reading and parsing the bytestream.
1473 // Note: VM callers should ensure consistency of k/class_name,class_loader
1474 instanceKlassHandle SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader, instanceKlassHandle k, TRAPS) {
1475 
1476   instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1477   Symbol*  name_h = k->name(); // passed in class_name may be null
1478   ClassLoaderData* loader_data = class_loader_data(class_loader);
1479 
1480   unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
1481   int d_index = dictionary()->hash_to_index(d_hash);
1482 
1483 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1484   unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
1485   int p_index = placeholders()->hash_to_index(p_hash);
1486   PlaceholderEntry* probe;
1487 
1488   {
1489     MutexLocker mu(SystemDictionary_lock, THREAD);
1490     // First check if class already defined
1491     if (UnsyncloadClass || (is_parallelDefine(class_loader))) {
1492       Klass* check = find_class(d_index, d_hash, name_h, loader_data);
1493       if (check != NULL) {
1494         return(instanceKlassHandle(THREAD, check));
1495       }
1496     }
1497 
1498     // Acquire define token for this class/classloader
1499     probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1500     // Wait if another thread defining in parallel
1501     // All threads wait - even those that will throw duplicate class: otherwise
1502     // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1503     // if other thread has not finished updating dictionary
1504     while (probe->definer() != NULL) {
1505       SystemDictionary_lock->wait();
1506     }
1507     // Only special cases allow parallel defines and can use other thread's results
1508     // Other cases fall through, and may run into duplicate defines
1509     // caught by finding an entry in the SystemDictionary
1510     if ((UnsyncloadClass || is_parallelDefine(class_loader)) && (probe->instance_klass() != NULL)) {
1511         placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1512         SystemDictionary_lock->notify_all();
1513 #ifdef ASSERT
1514         Klass* check = find_class(d_index, d_hash, name_h, loader_data);
1515         assert(check != NULL, "definer missed recording success");
1516 #endif
1517         return(instanceKlassHandle(THREAD, probe->instance_klass()));
1518     } else {
1519       // This thread will define the class (even if earlier thread tried and had an error)
1520       probe->set_definer(THREAD);
1521     }
1522   }
1523 
1524   define_instance_class(k, THREAD);
1525 
1526   Handle linkage_exception = Handle(); // null handle
1527 
1528   // definer must notify any waiting threads
1529   {
1530     MutexLocker mu(SystemDictionary_lock, THREAD);
1531     PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1532     assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1533     if (probe != NULL) {
1534       if (HAS_PENDING_EXCEPTION) {
1535         linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1536         CLEAR_PENDING_EXCEPTION;
1537       } else {
1538         probe->set_instance_klass(k());
1539       }
1540       probe->set_definer(NULL);
1541       placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1542       SystemDictionary_lock->notify_all();
1543     }
1544   }
1545 
1546   // Can't throw exception while holding lock due to rank ordering
1547   if (linkage_exception() != NULL) {
1548     THROW_OOP_(linkage_exception(), nh); // throws exception and returns
1549   }
1550 
1551   return k;
1552 }
1553 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1554   // If class_loader is NULL we synchronize on _system_loader_lock_obj
1555   if (class_loader.is_null()) {
1556     return Handle(THREAD, _system_loader_lock_obj);
1557   } else {
1558     return class_loader;
1559   }
1560 }
1561 
1562 // This method is added to check how often we have to wait to grab loader
1563 // lock. The results are being recorded in the performance counters defined in
1564 // ClassLoader::_sync_systemLoaderLockContentionRate and
1565 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1566 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1567   if (!UsePerfData) {
1568     return;
1569   }
1570 
1571   assert(!loader_lock.is_null(), "NULL lock object");
1572 
1573   if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1574       == ObjectSynchronizer::owner_other) {
1575     // contention will likely happen, so increment the corresponding
1576     // contention counter.
1577     if (loader_lock() == _system_loader_lock_obj) {
1578       ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1579     } else {
1580       ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1581     }
1582   }
1583 }
1584 
1585 // ----------------------------------------------------------------------------
1586 // Lookup
1587 
1588 Klass* SystemDictionary::find_class(int index, unsigned int hash,
1589                                       Symbol* class_name,
1590                                       ClassLoaderData* loader_data) {
1591   assert_locked_or_safepoint(SystemDictionary_lock);
1592   assert (index == dictionary()->index_for(class_name, loader_data),
1593           "incorrect index?");
1594 
1595   Klass* k = dictionary()->find_class(index, hash, class_name, loader_data);
1596   return k;
1597 }
1598 
1599 
1600 // Basic find on classes in the midst of being loaded
1601 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1602                                            ClassLoaderData* loader_data) {
1603   assert_locked_or_safepoint(SystemDictionary_lock);
1604   unsigned int p_hash = placeholders()->compute_hash(class_name, loader_data);
1605   int p_index = placeholders()->hash_to_index(p_hash);
1606   return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1607 }
1608 
1609 
1610 // Used for assertions and verification only
1611 Klass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1612   #ifndef ASSERT
1613   guarantee(VerifyBeforeGC      ||
1614             VerifyDuringGC      ||
1615             VerifyBeforeExit    ||
1616             VerifyDuringStartup ||
1617             VerifyAfterGC, "too expensive");
1618   #endif
1619   assert_locked_or_safepoint(SystemDictionary_lock);
1620 
1621   // First look in the loaded class array
1622   unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
1623   int d_index = dictionary()->hash_to_index(d_hash);
1624   return find_class(d_index, d_hash, class_name, loader_data);
1625 }
1626 
1627 
1628 // Get the next class in the diictionary.
1629 Klass* SystemDictionary::try_get_next_class() {
1630   return dictionary()->try_get_next_class();
1631 }
1632 
1633 
1634 // ----------------------------------------------------------------------------
1635 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1636 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1637 // before a new class is used.
1638 
1639 void SystemDictionary::add_to_hierarchy(instanceKlassHandle k, TRAPS) {
1640   assert(k.not_null(), "just checking");
1641   assert_locked_or_safepoint(Compile_lock);
1642 
1643   // Link into hierachy. Make sure the vtables are initialized before linking into
1644   k->append_to_sibling_list();                    // add to superklass/sibling list
1645   k->process_interfaces(THREAD);                  // handle all "implements" declarations
1646   k->set_init_state(InstanceKlass::loaded);
1647   // Now flush all code that depended on old class hierarchy.
1648   // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1649   // Also, first reinitialize vtable because it may have gotten out of synch
1650   // while the new class wasn't connected to the class hierarchy.
1651   Universe::flush_dependents_on(k);
1652 }
1653 
1654 
1655 // ----------------------------------------------------------------------------
1656 // GC support
1657 
1658 // Following roots during mark-sweep is separated in two phases.
1659 //
1660 // The first phase follows preloaded classes and all other system
1661 // classes, since these will never get unloaded anyway.
1662 //
1663 // The second phase removes (unloads) unreachable classes from the
1664 // system dictionary and follows the remaining classes' contents.
1665 
1666 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1667   blk->do_oop(&_java_system_loader);
1668   blk->do_oop(&_system_loader_lock_obj);
1669 
1670   dictionary()->always_strong_oops_do(blk);
1671 
1672   // Visit extra methods
1673   invoke_method_table()->oops_do(blk);
1674 }
1675 
1676 void SystemDictionary::always_strong_classes_do(KlassClosure* closure) {
1677   // Follow all system classes and temporary placeholders in dictionary
1678   dictionary()->always_strong_classes_do(closure);
1679 
1680   // Placeholders. These represent classes we're actively loading.
1681   placeholders()->classes_do(closure);
1682 }
1683 
1684 // Calculate a "good" systemdictionary size based
1685 // on predicted or current loaded classes count
1686 int SystemDictionary::calculate_systemdictionary_size(int classcount) {
1687   int newsize = _old_default_sdsize;
1688   if ((classcount > 0)  && !DumpSharedSpaces) {
1689     int desiredsize = classcount/_average_depth_goal;
1690     for (newsize = _primelist[_sdgeneration]; _sdgeneration < _prime_array_size -1;
1691          newsize = _primelist[++_sdgeneration]) {
1692       if (desiredsize <=  newsize) {
1693         break;
1694       }
1695     }
1696   }
1697   return newsize;
1698 }
1699 
1700 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1701 // Note: anonymous classes are not in the SD.
1702 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive) {
1703   // First, mark for unload all ClassLoaderData referencing a dead class loader.
1704   bool has_dead_loaders = ClassLoaderDataGraph::do_unloading(is_alive);
1705   bool unloading_occurred = false;
1706   if (has_dead_loaders) {
1707     unloading_occurred = dictionary()->do_unloading();
1708     constraints()->purge_loader_constraints();
1709     resolution_errors()->purge_resolution_errors();
1710 }
1711   return unloading_occurred;
1712 }
1713 
1714 void SystemDictionary::oops_do(OopClosure* f) {
1715   f->do_oop(&_java_system_loader);
1716   f->do_oop(&_system_loader_lock_obj);
1717 
1718   // Adjust dictionary
1719   dictionary()->oops_do(f);
1720 
1721   // Visit extra methods
1722   invoke_method_table()->oops_do(f);
1723 }
1724 
1725 // Extended Class redefinition support.
1726 // If one of these classes is replaced, we need to replace it in these places.
1727 // KlassClosure::do_klass should take the address of a class but we can
1728 // change that later.
1729 void SystemDictionary::preloaded_classes_do(KlassClosure* f) {
1730   for (int k = (int)FIRST_WKID; k < (int)WKID_LIMIT; k++) {
1731     f->do_klass(_well_known_klasses[k]);
1732   }
1733 
1734   {
1735     for (int i = 0; i < T_VOID+1; i++) {
1736       if (_box_klasses[i] != NULL) {
1737         assert(i >= T_BOOLEAN, "checking");
1738         f->do_klass(_box_klasses[i]);
1739       }
1740     }
1741   }
1742 
1743   FilteredFieldsMap::classes_do(f);
1744 }
1745 
1746 void SystemDictionary::lazily_loaded_classes_do(KlassClosure* f) {
1747   f->do_klass(_abstract_ownable_synchronizer_klass);
1748 }
1749 
1750 // Just the classes from defining class loaders
1751 // Don't iterate over placeholders
1752 void SystemDictionary::classes_do(void f(Klass*)) {
1753   dictionary()->classes_do(f);
1754 }
1755 
1756 // Added for initialize_itable_for_klass
1757 //   Just the classes from defining class loaders
1758 // Don't iterate over placeholders
1759 void SystemDictionary::classes_do(void f(Klass*, TRAPS), TRAPS) {
1760   dictionary()->classes_do(f, CHECK);
1761 }
1762 
1763 //   All classes, and their class loaders
1764 // Don't iterate over placeholders
1765 void SystemDictionary::classes_do(void f(Klass*, ClassLoaderData*)) {
1766   dictionary()->classes_do(f);
1767 }
1768 
1769 void SystemDictionary::placeholders_do(void f(Symbol*)) {
1770   placeholders()->entries_do(f);
1771 }
1772 
1773 void SystemDictionary::methods_do(void f(Method*)) {
1774   dictionary()->methods_do(f);
1775   invoke_method_table()->methods_do(f);
1776 }
1777 
1778 // ----------------------------------------------------------------------------
1779 // Lazily load klasses
1780 
1781 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
1782   assert(JDK_Version::is_gte_jdk16x_version(), "Must be JDK 1.6 or later");
1783 
1784   // if multiple threads calling this function, only one thread will load
1785   // the class.  The other threads will find the loaded version once the
1786   // class is loaded.
1787   Klass* aos = _abstract_ownable_synchronizer_klass;
1788   if (aos == NULL) {
1789     Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
1790     // Force a fence to prevent any read before the write completes
1791     OrderAccess::fence();
1792     _abstract_ownable_synchronizer_klass = k;
1793   }
1794 }
1795 
1796 // ----------------------------------------------------------------------------
1797 // Initialization
1798 
1799 void SystemDictionary::initialize(TRAPS) {
1800   // Allocate arrays
1801   assert(dictionary() == NULL,
1802          "SystemDictionary should only be initialized once");
1803   _sdgeneration        = 0;
1804   _dictionary          = new Dictionary(calculate_systemdictionary_size(PredictedLoadedClassCount));
1805   _placeholders        = new PlaceholderTable(_nof_buckets);
1806   _number_of_modifications = 0;
1807   _loader_constraints  = new LoaderConstraintTable(_loader_constraint_size);
1808   _resolution_errors   = new ResolutionErrorTable(_resolution_error_size);
1809   _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
1810 
1811   // Allocate private object used as system class loader lock
1812   _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
1813   // Initialize basic classes
1814   initialize_preloaded_classes(CHECK);
1815 }
1816 
1817 // Compact table of directions on the initialization of klasses:
1818 static const short wk_init_info[] = {
1819   #define WK_KLASS_INIT_INFO(name, symbol, option) \
1820     ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
1821           << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
1822       | (int)SystemDictionary::option ),
1823   WK_KLASSES_DO(WK_KLASS_INIT_INFO)
1824   #undef WK_KLASS_INIT_INFO
1825   0
1826 };
1827 
1828 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
1829   assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1830   int  info = wk_init_info[id - FIRST_WKID];
1831   int  sid  = (info >> CEIL_LG_OPTION_LIMIT);
1832   Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
1833   Klass**    klassp = &_well_known_klasses[id];
1834   bool must_load = (init_opt < SystemDictionary::Opt);
1835   if ((*klassp) == NULL) {
1836     if (must_load) {
1837       (*klassp) = resolve_or_fail(symbol, true, CHECK_0); // load required class
1838     } else {
1839       (*klassp) = resolve_or_null(symbol,       CHECK_0); // load optional klass
1840     }
1841   }
1842   return ((*klassp) != NULL);
1843 }
1844 
1845 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
1846   assert((int)start_id <= (int)limit_id, "IDs are out of order!");
1847   for (int id = (int)start_id; id < (int)limit_id; id++) {
1848     assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1849     int info = wk_init_info[id - FIRST_WKID];
1850     int sid  = (info >> CEIL_LG_OPTION_LIMIT);
1851     int opt  = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
1852 
1853     initialize_wk_klass((WKID)id, opt, CHECK);
1854   }
1855 
1856   // move the starting value forward to the limit:
1857   start_id = limit_id;
1858 }
1859 
1860 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
1861   assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
1862   // Preload commonly used klasses
1863   WKID scan = FIRST_WKID;
1864   // first do Object, then String, Class
1865   if (UseSharedSpaces) {
1866     initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
1867     // Initialize the constant pool for the Object_class
1868     InstanceKlass* ik = InstanceKlass::cast(Object_klass());
1869     ik->constants()->restore_unshareable_info(CHECK);
1870     initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1871   } else {
1872     initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1873   }
1874 
1875   // Calculate offsets for String and Class classes since they are loaded and
1876   // can be used after this point.
1877   java_lang_String::compute_offsets();
1878   java_lang_Class::compute_offsets();
1879 
1880   // Fixup mirrors for classes loaded before java.lang.Class.
1881   // These calls iterate over the objects currently in the perm gen
1882   // so calling them at this point is matters (not before when there
1883   // are fewer objects and not later after there are more objects
1884   // in the perm gen.
1885   Universe::initialize_basic_type_mirrors(CHECK);
1886   Universe::fixup_mirrors(CHECK);
1887 
1888   // do a bunch more:
1889   initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
1890 
1891   // Preload ref klasses and set reference types
1892   InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
1893   InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
1894 
1895   initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
1896   InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
1897   InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
1898   InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
1899   InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
1900 
1901   // JSR 292 classes
1902   WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
1903   WKID jsr292_group_end   = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
1904   initialize_wk_klasses_until(jsr292_group_start, scan, CHECK);
1905   if (EnableInvokeDynamic) {
1906     initialize_wk_klasses_through(jsr292_group_end, scan, CHECK);
1907   } else {
1908     // Skip the JSR 292 classes, if not enabled.
1909     scan = WKID(jsr292_group_end + 1);
1910   }
1911 
1912   initialize_wk_klasses_until(WKID_LIMIT, scan, CHECK);
1913 
1914   _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
1915   _box_klasses[T_CHAR]    = WK_KLASS(Character_klass);
1916   _box_klasses[T_FLOAT]   = WK_KLASS(Float_klass);
1917   _box_klasses[T_DOUBLE]  = WK_KLASS(Double_klass);
1918   _box_klasses[T_BYTE]    = WK_KLASS(Byte_klass);
1919   _box_klasses[T_SHORT]   = WK_KLASS(Short_klass);
1920   _box_klasses[T_INT]     = WK_KLASS(Integer_klass);
1921   _box_klasses[T_LONG]    = WK_KLASS(Long_klass);
1922   //_box_klasses[T_OBJECT]  = WK_KLASS(object_klass);
1923   //_box_klasses[T_ARRAY]   = WK_KLASS(object_klass);
1924 
1925   { // Compute whether we should use loadClass or loadClassInternal when loading classes.
1926     Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature());
1927     _has_loadClassInternal = (method != NULL);
1928   }
1929   { // Compute whether we should use checkPackageAccess or NOT
1930     Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
1931     _has_checkPackageAccess = (method != NULL);
1932   }
1933 }
1934 
1935 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
1936 // If so, returns the basic type it holds.  If not, returns T_OBJECT.
1937 BasicType SystemDictionary::box_klass_type(Klass* k) {
1938   assert(k != NULL, "");
1939   for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
1940     if (_box_klasses[i] == k)
1941       return (BasicType)i;
1942   }
1943   return T_OBJECT;
1944 }
1945 
1946 // Constraints on class loaders. The details of the algorithm can be
1947 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
1948 // Virtual Machine" by Sheng Liang and Gilad Bracha.  The basic idea is
1949 // that the system dictionary needs to maintain a set of contraints that
1950 // must be satisfied by all classes in the dictionary.
1951 // if defining is true, then LinkageError if already in systemDictionary
1952 // if initiating loader, then ok if InstanceKlass matches existing entry
1953 
1954 void SystemDictionary::check_constraints(int d_index, unsigned int d_hash,
1955                                          instanceKlassHandle k,
1956                                          Handle class_loader, bool defining,
1957                                          TRAPS) {
1958   const char *linkage_error = NULL;
1959   {
1960     Symbol*  name  = k->name();
1961     ClassLoaderData *loader_data = class_loader_data(class_loader);
1962 
1963     MutexLocker mu(SystemDictionary_lock, THREAD);
1964 
1965     Klass* check = find_class(d_index, d_hash, name, loader_data);
1966     if (check != (Klass*)NULL) {
1967       // if different InstanceKlass - duplicate class definition,
1968       // else - ok, class loaded by a different thread in parallel,
1969       // we should only have found it if it was done loading and ok to use
1970       // system dictionary only holds instance classes, placeholders
1971       // also holds array classes
1972 
1973       assert(check->oop_is_instance(), "noninstance in systemdictionary");
1974       if ((defining == true) || (k() != check)) {
1975         linkage_error = "loader (instance of  %s): attempted  duplicate class "
1976           "definition for name: \"%s\"";
1977       } else {
1978         return;
1979       }
1980     }
1981 
1982 #ifdef ASSERT
1983     Symbol* ph_check = find_placeholder(name, loader_data);
1984     assert(ph_check == NULL || ph_check == name, "invalid symbol");
1985 #endif
1986 
1987     if (linkage_error == NULL) {
1988       if (constraints()->check_or_update(k, class_loader, name) == false) {
1989         linkage_error = "loader constraint violation: loader (instance of %s)"
1990           " previously initiated loading for a different type with name \"%s\"";
1991       }
1992     }
1993   }
1994 
1995   // Throw error now if needed (cannot throw while holding
1996   // SystemDictionary_lock because of rank ordering)
1997 
1998   if (linkage_error) {
1999     ResourceMark rm(THREAD);
2000     const char* class_loader_name = loader_name(class_loader());
2001     char* type_name = k->name()->as_C_string();
2002     size_t buflen = strlen(linkage_error) + strlen(class_loader_name) +
2003       strlen(type_name);
2004     char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
2005     jio_snprintf(buf, buflen, linkage_error, class_loader_name, type_name);
2006     THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
2007   }
2008 }
2009 
2010 
2011 // Update system dictionary - done after check_constraint and add_to_hierachy
2012 // have been called.
2013 void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash,
2014                                          int p_index, unsigned int p_hash,
2015                                          instanceKlassHandle k,
2016                                          Handle class_loader,
2017                                          TRAPS) {
2018   // Compile_lock prevents systemDictionary updates during compilations
2019   assert_locked_or_safepoint(Compile_lock);
2020   Symbol*  name  = k->name();
2021   ClassLoaderData *loader_data = class_loader_data(class_loader);
2022 
2023   {
2024   MutexLocker mu1(SystemDictionary_lock, THREAD);
2025 
2026   // See whether biased locking is enabled and if so set it for this
2027   // klass.
2028   // Note that this must be done past the last potential blocking
2029   // point / safepoint. We enable biased locking lazily using a
2030   // VM_Operation to iterate the SystemDictionary and installing the
2031   // biasable mark word into each InstanceKlass's prototype header.
2032   // To avoid race conditions where we accidentally miss enabling the
2033   // optimization for one class in the process of being added to the
2034   // dictionary, we must not safepoint after the test of
2035   // BiasedLocking::enabled().
2036   if (UseBiasedLocking && BiasedLocking::enabled()) {
2037     // Set biased locking bit for all loaded classes; it will be
2038     // cleared if revocation occurs too often for this type
2039     // NOTE that we must only do this when the class is initally
2040     // defined, not each time it is referenced from a new class loader
2041     if (k->class_loader() == class_loader()) {
2042       k->set_prototype_header(markOopDesc::biased_locking_prototype());
2043     }
2044   }
2045 
2046   // Make a new system dictionary entry.
2047   Klass* sd_check = find_class(d_index, d_hash, name, loader_data);
2048   if (sd_check == NULL) {
2049     dictionary()->add_klass(name, loader_data, k);
2050     notice_modification();
2051   }
2052 #ifdef ASSERT
2053   sd_check = find_class(d_index, d_hash, name, loader_data);
2054   assert (sd_check != NULL, "should have entry in system dictionary");
2055   // Note: there may be a placeholder entry: for circularity testing
2056   // or for parallel defines
2057 #endif
2058     SystemDictionary_lock->notify_all();
2059   }
2060 }
2061 
2062 
2063 // Try to find a class name using the loader constraints.  The
2064 // loader constraints might know about a class that isn't fully loaded
2065 // yet and these will be ignored.
2066 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2067                     Symbol* class_name, Handle class_loader, TRAPS) {
2068 
2069   // First see if it has been loaded directly.
2070   // Force the protection domain to be null.  (This removes protection checks.)
2071   Handle no_protection_domain;
2072   Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2073                                               no_protection_domain, CHECK_NULL);
2074   if (klass != NULL)
2075     return klass;
2076 
2077   // Now look to see if it has been loaded elsewhere, and is subject to
2078   // a loader constraint that would require this loader to return the
2079   // klass that is already loaded.
2080   if (FieldType::is_array(class_name)) {
2081     // For array classes, their Klass*s are not kept in the
2082     // constraint table. The element Klass*s are.
2083     FieldArrayInfo fd;
2084     BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2085     if (t != T_OBJECT) {
2086       klass = Universe::typeArrayKlassObj(t);
2087     } else {
2088       MutexLocker mu(SystemDictionary_lock, THREAD);
2089       klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2090     }
2091     // If element class already loaded, allocate array klass
2092     if (klass != NULL) {
2093       klass = klass->array_klass_or_null(fd.dimension());
2094     }
2095   } else {
2096     MutexLocker mu(SystemDictionary_lock, THREAD);
2097     // Non-array classes are easy: simply check the constraint table.
2098     klass = constraints()->find_constrained_klass(class_name, class_loader);
2099   }
2100 
2101   return klass;
2102 }
2103 
2104 
2105 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2106                                              Handle class_loader1,
2107                                              Handle class_loader2,
2108                                              Thread* THREAD) {
2109   ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2110   ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2111 
2112   Symbol* constraint_name = NULL;
2113   if (!FieldType::is_array(class_name)) {
2114     constraint_name = class_name;
2115   } else {
2116     // For array classes, their Klass*s are not kept in the
2117     // constraint table. The element classes are.
2118     FieldArrayInfo fd;
2119     BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2120     // primitive types always pass
2121     if (t != T_OBJECT) {
2122       return true;
2123     } else {
2124       constraint_name = fd.object_key();
2125     }
2126   }
2127   unsigned int d_hash1 = dictionary()->compute_hash(constraint_name, loader_data1);
2128   int d_index1 = dictionary()->hash_to_index(d_hash1);
2129 
2130   unsigned int d_hash2 = dictionary()->compute_hash(constraint_name, loader_data2);
2131   int d_index2 = dictionary()->hash_to_index(d_hash2);
2132   {
2133   MutexLocker mu_s(SystemDictionary_lock, THREAD);
2134 
2135   // Better never do a GC while we're holding these oops
2136   No_Safepoint_Verifier nosafepoint;
2137 
2138   Klass* klass1 = find_class(d_index1, d_hash1, constraint_name, loader_data1);
2139   Klass* klass2 = find_class(d_index2, d_hash2, constraint_name, loader_data2);
2140   return constraints()->add_entry(constraint_name, klass1, class_loader1,
2141                                   klass2, class_loader2);
2142   }
2143 }
2144 
2145 // Add entry to resolution error table to record the error when the first
2146 // attempt to resolve a reference to a class has failed.
2147 void SystemDictionary::add_resolution_error(constantPoolHandle pool, int which, Symbol* error) {
2148   unsigned int hash = resolution_errors()->compute_hash(pool, which);
2149   int index = resolution_errors()->hash_to_index(hash);
2150   {
2151     MutexLocker ml(SystemDictionary_lock, Thread::current());
2152     resolution_errors()->add_entry(index, hash, pool, which, error);
2153   }
2154 }
2155 
2156 // Delete a resolution error for RedefineClasses for a constant pool is going away
2157 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2158   resolution_errors()->delete_entry(pool);
2159 }
2160 
2161 // Lookup resolution error table. Returns error if found, otherwise NULL.
2162 Symbol* SystemDictionary::find_resolution_error(constantPoolHandle pool, int which) {
2163   unsigned int hash = resolution_errors()->compute_hash(pool, which);
2164   int index = resolution_errors()->hash_to_index(hash);
2165   {
2166     MutexLocker ml(SystemDictionary_lock, Thread::current());
2167     ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2168     return (entry != NULL) ? entry->error() : (Symbol*)NULL;
2169   }
2170 }
2171 
2172 
2173 // Signature constraints ensure that callers and callees agree about
2174 // the meaning of type names in their signatures.  This routine is the
2175 // intake for constraints.  It collects them from several places:
2176 //
2177 //  * LinkResolver::resolve_method (if check_access is true) requires
2178 //    that the resolving class (the caller) and the defining class of
2179 //    the resolved method (the callee) agree on each type in the
2180 //    method's signature.
2181 //
2182 //  * LinkResolver::resolve_interface_method performs exactly the same
2183 //    checks.
2184 //
2185 //  * LinkResolver::resolve_field requires that the constant pool
2186 //    attempting to link to a field agree with the field's defining
2187 //    class about the type of the field signature.
2188 //
2189 //  * klassVtable::initialize_vtable requires that, when a class
2190 //    overrides a vtable entry allocated by a superclass, that the
2191 //    overriding method (i.e., the callee) agree with the superclass
2192 //    on each type in the method's signature.
2193 //
2194 //  * klassItable::initialize_itable requires that, when a class fills
2195 //    in its itables, for each non-abstract method installed in an
2196 //    itable, the method (i.e., the callee) agree with the interface
2197 //    on each type in the method's signature.
2198 //
2199 // All those methods have a boolean (check_access, checkconstraints)
2200 // which turns off the checks.  This is used from specialized contexts
2201 // such as bootstrapping, dumping, and debugging.
2202 //
2203 // No direct constraint is placed between the class and its
2204 // supertypes.  Constraints are only placed along linked relations
2205 // between callers and callees.  When a method overrides or implements
2206 // an abstract method in a supertype (superclass or interface), the
2207 // constraints are placed as if the supertype were the caller to the
2208 // overriding method.  (This works well, since callers to the
2209 // supertype have already established agreement between themselves and
2210 // the supertype.)  As a result of all this, a class can disagree with
2211 // its supertype about the meaning of a type name, as long as that
2212 // class neither calls a relevant method of the supertype, nor is
2213 // called (perhaps via an override) from the supertype.
2214 //
2215 //
2216 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2217 //
2218 // Make sure all class components (including arrays) in the given
2219 // signature will be resolved to the same class in both loaders.
2220 // Returns the name of the type that failed a loader constraint check, or
2221 // NULL if no constraint failed.  No exception except OOME is thrown.
2222 // Arrays are not added to the loader constraint table, their elements are.
2223 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2224                                                Handle loader1, Handle loader2,
2225                                                bool is_method, TRAPS)  {
2226   // Nothing to do if loaders are the same.
2227   if (loader1() == loader2()) {
2228     return NULL;
2229   }
2230 
2231   SignatureStream sig_strm(signature, is_method);
2232   while (!sig_strm.is_done()) {
2233     if (sig_strm.is_object()) {
2234       Symbol* sig = sig_strm.as_symbol(CHECK_NULL);
2235       if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2236         return sig;
2237       }
2238     }
2239     sig_strm.next();
2240   }
2241   return NULL;
2242 }
2243 
2244 
2245 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2246                                                             Symbol* signature,
2247                                                             TRAPS) {
2248   methodHandle empty;
2249   assert(EnableInvokeDynamic, "");
2250   assert(MethodHandles::is_signature_polymorphic(iid) &&
2251          MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2252          iid != vmIntrinsics::_invokeGeneric,
2253          err_msg("must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid)));
2254 
2255   unsigned int hash  = invoke_method_table()->compute_hash(signature, iid);
2256   int          index = invoke_method_table()->hash_to_index(hash);
2257   SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2258   methodHandle m;
2259   if (spe == NULL || spe->method() == NULL) {
2260     spe = NULL;
2261     // Must create lots of stuff here, but outside of the SystemDictionary lock.
2262     m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2263     CompileBroker::compile_method(m, InvocationEntryBci, CompLevel_highest_tier,
2264                                   methodHandle(), CompileThreshold, "MH", CHECK_(empty));
2265 
2266     // Now grab the lock.  We might have to throw away the new method,
2267     // if a racing thread has managed to install one at the same time.
2268     {
2269       MutexLocker ml(SystemDictionary_lock, THREAD);
2270       spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2271       if (spe == NULL)
2272         spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2273       if (spe->method() == NULL)
2274         spe->set_method(m());
2275     }
2276   }
2277 
2278   assert(spe != NULL && spe->method() != NULL, "");
2279   return spe->method();
2280 }
2281 
2282 // Helper for unpacking the return value from linkMethod and linkCallSite.
2283 static methodHandle unpack_method_and_appendix(Handle mname,
2284                                                KlassHandle accessing_klass,
2285                                                objArrayHandle appendix_box,
2286                                                Handle* appendix_result,
2287                                                TRAPS) {
2288   methodHandle empty;
2289   if (mname.not_null()) {
2290     Metadata* vmtarget = java_lang_invoke_MemberName::vmtarget(mname());
2291     if (vmtarget != NULL && vmtarget->is_method()) {
2292       Method* m = (Method*)vmtarget;
2293       oop appendix = appendix_box->obj_at(0);
2294       if (TraceMethodHandles) {
2295     #ifndef PRODUCT
2296         tty->print("Linked method="INTPTR_FORMAT": ", m);
2297         m->print();
2298         if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2299         tty->cr();
2300     #endif //PRODUCT
2301       }
2302       (*appendix_result) = Handle(THREAD, appendix);
2303       // the target is stored in the cpCache and if a reference to this
2304       // MethodName is dropped we need a way to make sure the
2305       // class_loader containing this method is kept alive.
2306       // FIXME: the appendix might also preserve this dependency.
2307       ClassLoaderData* this_key = InstanceKlass::cast(accessing_klass())->class_loader_data();
2308       this_key->record_dependency(m->method_holder(), CHECK_NULL); // Can throw OOM
2309       return methodHandle(THREAD, m);
2310     }
2311   }
2312   THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2313   return empty;
2314 }
2315 
2316 methodHandle SystemDictionary::find_method_handle_invoker(Symbol* name,
2317                                                           Symbol* signature,
2318                                                           KlassHandle accessing_klass,
2319                                                           Handle *appendix_result,
2320                                                           Handle *method_type_result,
2321                                                           TRAPS) {
2322   methodHandle empty;
2323   assert(EnableInvokeDynamic, "");
2324   assert(!THREAD->is_Compiler_thread(), "");
2325   Handle method_type =
2326     SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2327   if (false) {  // FIXME: Decide if the Java upcall should resolve signatures.
2328     method_type = java_lang_String::create_from_symbol(signature, CHECK_(empty));
2329   }
2330 
2331   KlassHandle  mh_klass = SystemDictionary::MethodHandle_klass();
2332   int ref_kind = JVM_REF_invokeVirtual;
2333   Handle name_str = StringTable::intern(name, CHECK_(empty));
2334   objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2335   assert(appendix_box->obj_at(0) == NULL, "");
2336 
2337   // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2338   JavaCallArguments args;
2339   args.push_oop(accessing_klass()->java_mirror());
2340   args.push_int(ref_kind);
2341   args.push_oop(mh_klass()->java_mirror());
2342   args.push_oop(name_str());
2343   args.push_oop(method_type());
2344   args.push_oop(appendix_box());
2345   JavaValue result(T_OBJECT);
2346   JavaCalls::call_static(&result,
2347                          SystemDictionary::MethodHandleNatives_klass(),
2348                          vmSymbols::linkMethod_name(),
2349                          vmSymbols::linkMethod_signature(),
2350                          &args, CHECK_(empty));
2351   Handle mname(THREAD, (oop) result.get_jobject());
2352   (*method_type_result) = method_type;
2353   return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2354 }
2355 
2356 
2357 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2358 // signature, as interpreted relative to the given class loader.
2359 // Because of class loader constraints, all method handle usage must be
2360 // consistent with this loader.
2361 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2362                                                  KlassHandle accessing_klass,
2363                                                  TRAPS) {
2364   Handle empty;
2365   vmIntrinsics::ID null_iid = vmIntrinsics::_none;  // distinct from all method handle invoker intrinsics
2366   unsigned int hash  = invoke_method_table()->compute_hash(signature, null_iid);
2367   int          index = invoke_method_table()->hash_to_index(hash);
2368   SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2369   if (spe != NULL && spe->method_type() != NULL) {
2370     assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2371     return Handle(THREAD, spe->method_type());
2372   } else if (THREAD->is_Compiler_thread()) {
2373     warning("SystemDictionary::find_method_handle_type called from compiler thread");  // FIXME
2374     return Handle();  // do not attempt from within compiler, unless it was cached
2375   }
2376 
2377   Handle class_loader, protection_domain;
2378   bool is_on_bcp = true;  // keep this true as long as we can materialize from the boot classloader
2379   int npts = ArgumentCount(signature).size();
2380   objArrayHandle pts = oopFactory::new_objArray(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2381   int arg = 0;
2382   Handle rt;                            // the return type from the signature
2383   ResourceMark rm(THREAD);
2384   for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2385     oop mirror = NULL;
2386     if (is_on_bcp) {
2387       // Note:  class_loader & protection_domain are both null at this point.
2388       mirror = ss.as_java_mirror(class_loader, protection_domain,
2389                                  SignatureStream::ReturnNull, CHECK_(empty));
2390       if (mirror == NULL) {
2391         // fall back from BCP to accessing_klass
2392         if (accessing_klass.not_null()) {
2393           class_loader      = Handle(THREAD, InstanceKlass::cast(accessing_klass())->class_loader());
2394           protection_domain = Handle(THREAD, InstanceKlass::cast(accessing_klass())->protection_domain());
2395         }
2396         is_on_bcp = false;
2397       }
2398     }
2399     if (!is_on_bcp) {
2400       // Resolve, throwing a real error if it doesn't work.
2401       mirror = ss.as_java_mirror(class_loader, protection_domain,
2402                                  SignatureStream::NCDFError, CHECK_(empty));
2403     }
2404     if (ss.at_return_type())
2405       rt = Handle(THREAD, mirror);
2406     else
2407       pts->obj_at_put(arg++, mirror);
2408 
2409     // Check accessibility.
2410     if (ss.is_object() && accessing_klass.not_null()) {
2411       Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2412       mirror = NULL;  // safety
2413       // Emulate ConstantPool::verify_constant_pool_resolve.
2414       if (sel_klass->oop_is_objArray())
2415         sel_klass = ObjArrayKlass::cast(sel_klass)->bottom_klass();
2416       if (sel_klass->oop_is_instance()) {
2417         KlassHandle sel_kh(THREAD, sel_klass);
2418         LinkResolver::check_klass_accessability(accessing_klass, sel_kh, CHECK_(empty));
2419       }
2420     }
2421   }
2422   assert(arg == npts, "");
2423 
2424   // call java.lang.invoke.MethodHandleNatives::findMethodType(Class rt, Class[] pts) -> MethodType
2425   JavaCallArguments args(Handle(THREAD, rt()));
2426   args.push_oop(pts());
2427   JavaValue result(T_OBJECT);
2428   JavaCalls::call_static(&result,
2429                          SystemDictionary::MethodHandleNatives_klass(),
2430                          vmSymbols::findMethodHandleType_name(),
2431                          vmSymbols::findMethodHandleType_signature(),
2432                          &args, CHECK_(empty));
2433   Handle method_type(THREAD, (oop) result.get_jobject());
2434 
2435   if (is_on_bcp) {
2436     // We can cache this MethodType inside the JVM.
2437     MutexLocker ml(SystemDictionary_lock, THREAD);
2438     spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2439     if (spe == NULL)
2440       spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2441     if (spe->method_type() == NULL) {
2442       spe->set_method_type(method_type());
2443     }
2444   }
2445 
2446   // report back to the caller with the MethodType
2447   return method_type;
2448 }
2449 
2450 // Ask Java code to find or construct a method handle constant.
2451 Handle SystemDictionary::link_method_handle_constant(KlassHandle caller,
2452                                                      int ref_kind, //e.g., JVM_REF_invokeVirtual
2453                                                      KlassHandle callee,
2454                                                      Symbol* name_sym,
2455                                                      Symbol* signature,
2456                                                      TRAPS) {
2457   Handle empty;
2458   Handle name = java_lang_String::create_from_symbol(name_sym, CHECK_(empty));
2459   Handle type;
2460   if (signature->utf8_length() > 0 && signature->byte_at(0) == '(') {
2461     type = find_method_handle_type(signature, caller, CHECK_(empty));
2462   } else {
2463     ResourceMark rm(THREAD);
2464     SignatureStream ss(signature, false);
2465     if (!ss.is_done()) {
2466       oop mirror = ss.as_java_mirror(caller->class_loader(), caller->protection_domain(),
2467                                      SignatureStream::NCDFError, CHECK_(empty));
2468       type = Handle(THREAD, mirror);
2469       ss.next();
2470       if (!ss.is_done())  type = Handle();  // error!
2471     }
2472   }
2473   if (type.is_null()) {
2474     THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad signature", empty);
2475   }
2476 
2477   // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2478   JavaCallArguments args;
2479   args.push_oop(caller->java_mirror());  // the referring class
2480   args.push_int(ref_kind);
2481   args.push_oop(callee->java_mirror());  // the target class
2482   args.push_oop(name());
2483   args.push_oop(type());
2484   JavaValue result(T_OBJECT);
2485   JavaCalls::call_static(&result,
2486                          SystemDictionary::MethodHandleNatives_klass(),
2487                          vmSymbols::linkMethodHandleConstant_name(),
2488                          vmSymbols::linkMethodHandleConstant_signature(),
2489                          &args, CHECK_(empty));
2490   return Handle(THREAD, (oop) result.get_jobject());
2491 }
2492 
2493 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2494 // name and signature, as interpreted relative to the given class loader.
2495 methodHandle SystemDictionary::find_dynamic_call_site_invoker(KlassHandle caller,
2496                                                               Handle bootstrap_specifier,
2497                                                               Symbol* name,
2498                                                               Symbol* type,
2499                                                               Handle *appendix_result,
2500                                                               Handle *method_type_result,
2501                                                               TRAPS) {
2502   methodHandle empty;
2503   Handle bsm, info;
2504   if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2505     bsm = bootstrap_specifier;
2506   } else {
2507     assert(bootstrap_specifier->is_objArray(), "");
2508     objArrayHandle args(THREAD, (objArrayOop) bootstrap_specifier());
2509     int len = args->length();
2510     assert(len >= 1, "");
2511     bsm = Handle(THREAD, args->obj_at(0));
2512     if (len > 1) {
2513       objArrayOop args1 = oopFactory::new_objArray(SystemDictionary::Object_klass(), len-1, CHECK_(empty));
2514       for (int i = 1; i < len; i++)
2515         args1->obj_at_put(i-1, args->obj_at(i));
2516       info = Handle(THREAD, args1);
2517     }
2518   }
2519   guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2520             "caller must supply a valid BSM");
2521 
2522   Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2523   Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2524 
2525   objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2526   assert(appendix_box->obj_at(0) == NULL, "");
2527 
2528   // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, bsm, name, mtype, info, &appendix)
2529   JavaCallArguments args;
2530   args.push_oop(caller->java_mirror());
2531   args.push_oop(bsm());
2532   args.push_oop(method_name());
2533   args.push_oop(method_type());
2534   args.push_oop(info());
2535   args.push_oop(appendix_box);
2536   JavaValue result(T_OBJECT);
2537   JavaCalls::call_static(&result,
2538                          SystemDictionary::MethodHandleNatives_klass(),
2539                          vmSymbols::linkCallSite_name(),
2540                          vmSymbols::linkCallSite_signature(),
2541                          &args, CHECK_(empty));
2542   Handle mname(THREAD, (oop) result.get_jobject());
2543   (*method_type_result) = method_type;
2544   return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
2545 }
2546 
2547 // Since the identity hash code for symbols changes when the symbols are
2548 // moved from the regular perm gen (hash in the mark word) to the shared
2549 // spaces (hash is the address), the classes loaded into the dictionary
2550 // may be in the wrong buckets.
2551 
2552 void SystemDictionary::reorder_dictionary() {
2553   dictionary()->reorder_dictionary();
2554 }
2555 
2556 
2557 void SystemDictionary::copy_buckets(char** top, char* end) {
2558   dictionary()->copy_buckets(top, end);
2559 }
2560 
2561 
2562 void SystemDictionary::copy_table(char** top, char* end) {
2563   dictionary()->copy_table(top, end);
2564 }
2565 
2566 
2567 void SystemDictionary::reverse() {
2568   dictionary()->reverse();
2569 }
2570 
2571 int SystemDictionary::number_of_classes() {
2572   return dictionary()->number_of_entries();
2573 }
2574 
2575 
2576 // ----------------------------------------------------------------------------
2577 #ifndef PRODUCT
2578 
2579 void SystemDictionary::print() {
2580   dictionary()->print();
2581 
2582   // Placeholders
2583   GCMutexLocker mu(SystemDictionary_lock);
2584   placeholders()->print();
2585 
2586   // loader constraints - print under SD_lock
2587   constraints()->print();
2588 }
2589 
2590 #endif
2591 
2592 void SystemDictionary::verify() {
2593   guarantee(dictionary() != NULL, "Verify of system dictionary failed");
2594   guarantee(constraints() != NULL,
2595             "Verify of loader constraints failed");
2596   guarantee(dictionary()->number_of_entries() >= 0 &&
2597             placeholders()->number_of_entries() >= 0,
2598             "Verify of system dictionary failed");
2599 
2600   // Verify dictionary
2601   dictionary()->verify();
2602 
2603   GCMutexLocker mu(SystemDictionary_lock);
2604   placeholders()->verify();
2605 
2606   // Verify constraint table
2607   guarantee(constraints() != NULL, "Verify of loader constraints failed");
2608   constraints()->verify(dictionary(), placeholders());
2609 }
2610 
2611 
2612 void SystemDictionary::verify_obj_klass_present(Symbol* class_name,
2613                                                 ClassLoaderData* loader_data) {
2614   GCMutexLocker mu(SystemDictionary_lock);
2615   Symbol* name;
2616 
2617   Klass* probe = find_class(class_name, loader_data);
2618   if (probe == NULL) {
2619     probe = SystemDictionary::find_shared_class(class_name);
2620     if (probe == NULL) {
2621       name = find_placeholder(class_name, loader_data);
2622     }
2623   }
2624   guarantee(probe != NULL || name != NULL,
2625             "Loaded klasses should be in SystemDictionary");
2626 }
2627 
2628 // utility function for class load event
2629 void SystemDictionary::post_class_load_event(TracingTime start_time,
2630                                              instanceKlassHandle k,
2631                                              Handle initiating_loader) {
2632 #if INCLUDE_TRACE
2633   EventClassLoad event(UNTIMED);
2634   if (event.should_commit()) {
2635     event.set_endtime(Tracing::time());
2636     event.set_starttime(start_time);
2637     event.set_loadedClass(k());
2638     oop defining_class_loader = k->class_loader();
2639     event.set_definingClassLoader(defining_class_loader !=  NULL ?
2640                                     defining_class_loader->klass() : (Klass*)NULL);
2641     oop class_loader = initiating_loader.is_null() ? (oop)NULL : initiating_loader();
2642     event.set_initiatingClassLoader(class_loader != NULL ?
2643                                       class_loader->klass() : (Klass*)NULL);
2644     event.commit();
2645   }
2646 #endif /* INCLUDE_TRACE */
2647 }
2648 
2649 #ifndef PRODUCT
2650 
2651 // statistics code
2652 class ClassStatistics: AllStatic {
2653  private:
2654   static int nclasses;        // number of classes
2655   static int nmethods;        // number of methods
2656   static int nmethoddata;     // number of methodData
2657   static int class_size;      // size of class objects in words
2658   static int method_size;     // size of method objects in words
2659   static int debug_size;      // size of debug info in methods
2660   static int methoddata_size; // size of methodData objects in words
2661 
2662   static void do_class(Klass* k) {
2663     nclasses++;
2664     class_size += k->size();
2665     if (k->oop_is_instance()) {
2666       InstanceKlass* ik = (InstanceKlass*)k;
2667       class_size += ik->methods()->size();
2668       class_size += ik->constants()->size();
2669       class_size += ik->local_interfaces()->size();
2670       class_size += ik->transitive_interfaces()->size();
2671       // We do not have to count implementors, since we only store one!
2672       // SSS: How should these be accounted now that they have moved?
2673       // class_size += ik->fields()->length();
2674     }
2675   }
2676 
2677   static void do_method(Method* m) {
2678     nmethods++;
2679     method_size += m->size();
2680     // class loader uses same objArray for empty vectors, so don't count these
2681     if (m->has_stackmap_table()) {
2682       method_size += m->stackmap_data()->size();
2683     }
2684 
2685     MethodData* mdo = m->method_data();
2686     if (mdo != NULL) {
2687       nmethoddata++;
2688       methoddata_size += mdo->size();
2689     }
2690   }
2691 
2692  public:
2693   static void print() {
2694     SystemDictionary::classes_do(do_class);
2695     SystemDictionary::methods_do(do_method);
2696     tty->print_cr("Class statistics:");
2697     tty->print_cr("%d classes (%d bytes)", nclasses, class_size * oopSize);
2698     tty->print_cr("%d methods (%d bytes = %d base + %d debug info)", nmethods,
2699                   (method_size + debug_size) * oopSize, method_size * oopSize, debug_size * oopSize);
2700     tty->print_cr("%d methoddata (%d bytes)", nmethoddata, methoddata_size * oopSize);
2701   }
2702 };
2703 
2704 
2705 int ClassStatistics::nclasses        = 0;
2706 int ClassStatistics::nmethods        = 0;
2707 int ClassStatistics::nmethoddata     = 0;
2708 int ClassStatistics::class_size      = 0;
2709 int ClassStatistics::method_size     = 0;
2710 int ClassStatistics::debug_size      = 0;
2711 int ClassStatistics::methoddata_size = 0;
2712 
2713 void SystemDictionary::print_class_statistics() {
2714   ResourceMark rm;
2715   ClassStatistics::print();
2716 }
2717 
2718 
2719 class MethodStatistics: AllStatic {
2720  public:
2721   enum {
2722     max_parameter_size = 10
2723   };
2724  private:
2725 
2726   static int _number_of_methods;
2727   static int _number_of_final_methods;
2728   static int _number_of_static_methods;
2729   static int _number_of_native_methods;
2730   static int _number_of_synchronized_methods;
2731   static int _number_of_profiled_methods;
2732   static int _number_of_bytecodes;
2733   static int _parameter_size_profile[max_parameter_size];
2734   static int _bytecodes_profile[Bytecodes::number_of_java_codes];
2735 
2736   static void initialize() {
2737     _number_of_methods        = 0;
2738     _number_of_final_methods  = 0;
2739     _number_of_static_methods = 0;
2740     _number_of_native_methods = 0;
2741     _number_of_synchronized_methods = 0;
2742     _number_of_profiled_methods = 0;
2743     _number_of_bytecodes      = 0;
2744     for (int i = 0; i < max_parameter_size             ; i++) _parameter_size_profile[i] = 0;
2745     for (int j = 0; j < Bytecodes::number_of_java_codes; j++) _bytecodes_profile     [j] = 0;
2746   };
2747 
2748   static void do_method(Method* m) {
2749     _number_of_methods++;
2750     // collect flag info
2751     if (m->is_final()       ) _number_of_final_methods++;
2752     if (m->is_static()      ) _number_of_static_methods++;
2753     if (m->is_native()      ) _number_of_native_methods++;
2754     if (m->is_synchronized()) _number_of_synchronized_methods++;
2755     if (m->method_data() != NULL) _number_of_profiled_methods++;
2756     // collect parameter size info (add one for receiver, if any)
2757     _parameter_size_profile[MIN2(m->size_of_parameters() + (m->is_static() ? 0 : 1), max_parameter_size - 1)]++;
2758     // collect bytecodes info
2759     {
2760       Thread *thread = Thread::current();
2761       HandleMark hm(thread);
2762       BytecodeStream s(methodHandle(thread, m));
2763       Bytecodes::Code c;
2764       while ((c = s.next()) >= 0) {
2765         _number_of_bytecodes++;
2766         _bytecodes_profile[c]++;
2767       }
2768     }
2769   }
2770 
2771  public:
2772   static void print() {
2773     initialize();
2774     SystemDictionary::methods_do(do_method);
2775     // generate output
2776     tty->cr();
2777     tty->print_cr("Method statistics (static):");
2778     // flag distribution
2779     tty->cr();
2780     tty->print_cr("%6d final        methods  %6.1f%%", _number_of_final_methods       , _number_of_final_methods        * 100.0F / _number_of_methods);
2781     tty->print_cr("%6d static       methods  %6.1f%%", _number_of_static_methods      , _number_of_static_methods       * 100.0F / _number_of_methods);
2782     tty->print_cr("%6d native       methods  %6.1f%%", _number_of_native_methods      , _number_of_native_methods       * 100.0F / _number_of_methods);
2783     tty->print_cr("%6d synchronized methods  %6.1f%%", _number_of_synchronized_methods, _number_of_synchronized_methods * 100.0F / _number_of_methods);
2784     tty->print_cr("%6d profiled     methods  %6.1f%%", _number_of_profiled_methods, _number_of_profiled_methods * 100.0F / _number_of_methods);
2785     // parameter size profile
2786     tty->cr();
2787     { int tot = 0;
2788       int avg = 0;
2789       for (int i = 0; i < max_parameter_size; i++) {
2790         int n = _parameter_size_profile[i];
2791         tot += n;
2792         avg += n*i;
2793         tty->print_cr("parameter size = %1d: %6d methods  %5.1f%%", i, n, n * 100.0F / _number_of_methods);
2794       }
2795       assert(tot == _number_of_methods, "should be the same");
2796       tty->print_cr("                    %6d methods  100.0%%", _number_of_methods);
2797       tty->print_cr("(average parameter size = %3.1f including receiver, if any)", (float)avg / _number_of_methods);
2798     }
2799     // bytecodes profile
2800     tty->cr();
2801     { int tot = 0;
2802       for (int i = 0; i < Bytecodes::number_of_java_codes; i++) {
2803         if (Bytecodes::is_defined(i)) {
2804           Bytecodes::Code c = Bytecodes::cast(i);
2805           int n = _bytecodes_profile[c];
2806           tot += n;
2807           tty->print_cr("%9d  %7.3f%%  %s", n, n * 100.0F / _number_of_bytecodes, Bytecodes::name(c));
2808         }
2809       }
2810       assert(tot == _number_of_bytecodes, "should be the same");
2811       tty->print_cr("%9d  100.000%%", _number_of_bytecodes);
2812     }
2813     tty->cr();
2814   }
2815 };
2816 
2817 int MethodStatistics::_number_of_methods;
2818 int MethodStatistics::_number_of_final_methods;
2819 int MethodStatistics::_number_of_static_methods;
2820 int MethodStatistics::_number_of_native_methods;
2821 int MethodStatistics::_number_of_synchronized_methods;
2822 int MethodStatistics::_number_of_profiled_methods;
2823 int MethodStatistics::_number_of_bytecodes;
2824 int MethodStatistics::_parameter_size_profile[MethodStatistics::max_parameter_size];
2825 int MethodStatistics::_bytecodes_profile[Bytecodes::number_of_java_codes];
2826 
2827 
2828 void SystemDictionary::print_method_statistics() {
2829   MethodStatistics::print();
2830 }
2831 
2832 #endif // PRODUCT