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