1 /*
   2  * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "classfile/classLoaderData.inline.hpp"
  27 #include "classfile/dictionary.hpp"
  28 #include "classfile/javaClasses.hpp"
  29 #include "classfile/loaderConstraints.hpp"
  30 #include "classfile/placeholders.hpp"
  31 #include "classfile/resolutionErrors.hpp"
  32 #include "classfile/stringTable.hpp"
  33 #include "classfile/systemDictionary.hpp"
  34 #if INCLUDE_CDS
  35 #include "classfile/sharedClassUtil.hpp"
  36 #include "classfile/systemDictionaryShared.hpp"
  37 #endif
  38 #include "classfile/vmSymbols.hpp"
  39 #include "compiler/compileBroker.hpp"
  40 #include "interpreter/bytecodeStream.hpp"
  41 #include "interpreter/interpreter.hpp"
  42 #include "memory/filemap.hpp"
  43 #include "memory/gcLocker.hpp"
  44 #include "memory/oopFactory.hpp"
  45 #include "oops/instanceKlass.hpp"
  46 #include "oops/instanceRefKlass.hpp"
  47 #include "oops/klass.inline.hpp"
  48 #include "oops/methodData.hpp"
  49 #include "oops/objArrayKlass.hpp"
  50 #include "oops/oop.inline.hpp"
  51 #include "oops/oop.inline2.hpp"
  52 #include "oops/typeArrayKlass.hpp"
  53 #include "prims/jvmtiEnvBase.hpp"
  54 #include "prims/methodHandles.hpp"
  55 #include "runtime/biasedLocking.hpp"
  56 #include "runtime/fieldType.hpp"
  57 #include "runtime/handles.inline.hpp"
  58 #include "runtime/java.hpp"
  59 #include "runtime/javaCalls.hpp"
  60 #include "runtime/mutexLocker.hpp"
  61 #include "runtime/orderAccess.inline.hpp"
  62 #include "runtime/signature.hpp"
  63 #include "services/classLoadingService.hpp"
  64 #include "services/threadService.hpp"
  65 #include "utilities/macros.hpp"
  66 #include "utilities/ticks.hpp"
  67 
  68 #if INCLUDE_TRACE
  69  #include "trace/tracing.hpp"
  70 #endif
  71 
  72 Dictionary*            SystemDictionary::_dictionary          = NULL;
  73 PlaceholderTable*      SystemDictionary::_placeholders        = NULL;
  74 Dictionary*            SystemDictionary::_shared_dictionary   = NULL;
  75 LoaderConstraintTable* SystemDictionary::_loader_constraints  = NULL;
  76 ResolutionErrorTable*  SystemDictionary::_resolution_errors   = NULL;
  77 SymbolPropertyTable*   SystemDictionary::_invoke_method_table = NULL;
  78 
  79 
  80 int         SystemDictionary::_number_of_modifications = 0;
  81 int         SystemDictionary::_sdgeneration               = 0;
  82 const int   SystemDictionary::_primelist[_prime_array_size] = {1009,2017,4049,5051,10103,
  83               20201,40423,99991};
  84 
  85 oop         SystemDictionary::_system_loader_lock_obj     =  NULL;
  86 
  87 Klass*      SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
  88                                                           =  { NULL /*, NULL...*/ };
  89 
  90 Klass*      SystemDictionary::_box_klasses[T_VOID+1]      =  { NULL /*, NULL...*/ };
  91 
  92 oop         SystemDictionary::_java_system_loader         =  NULL;
  93 
  94 bool        SystemDictionary::_has_loadClassInternal      =  false;
  95 bool        SystemDictionary::_has_checkPackageAccess     =  false;
  96 
  97 // lazily initialized klass variables
  98 Klass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
  99 
 100 
 101 // ----------------------------------------------------------------------------
 102 // Java-level SystemLoader
 103 
 104 oop SystemDictionary::java_system_loader() {
 105   return _java_system_loader;
 106 }
 107 
 108 void SystemDictionary::compute_java_system_loader(TRAPS) {
 109   KlassHandle system_klass(THREAD, WK_KLASS(ClassLoader_klass));
 110   JavaValue result(T_OBJECT);
 111   JavaCalls::call_static(&result,
 112                          KlassHandle(THREAD, WK_KLASS(ClassLoader_klass)),
 113                          vmSymbols::getSystemClassLoader_name(),
 114                          vmSymbols::void_classloader_signature(),
 115                          CHECK);
 116 
 117   _java_system_loader = (oop)result.get_jobject();
 118 
 119   CDS_ONLY(SystemDictionaryShared::initialize(CHECK);)
 120 }
 121 
 122 
 123 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, TRAPS) {
 124   if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
 125   return ClassLoaderDataGraph::find_or_create(class_loader, CHECK_NULL);
 126 }
 127 
 128 // ----------------------------------------------------------------------------
 129 // debugging
 130 
 131 #ifdef ASSERT
 132 
 133 // return true if class_name contains no '.' (internal format is '/')
 134 bool SystemDictionary::is_internal_format(Symbol* class_name) {
 135   if (class_name != NULL) {
 136     ResourceMark rm;
 137     char* name = class_name->as_C_string();
 138     return strchr(name, '.') == NULL;
 139   } else {
 140     return true;
 141   }
 142 }
 143 
 144 #endif
 145 
 146 // ----------------------------------------------------------------------------
 147 // Parallel class loading check
 148 
 149 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
 150   if (UnsyncloadClass || class_loader.is_null()) return true;
 151   if (AlwaysLockClassLoader) return false;
 152   return java_lang_ClassLoader::parallelCapable(class_loader());
 153 }
 154 // ----------------------------------------------------------------------------
 155 // ParallelDefineClass flag does not apply to bootclass loader
 156 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
 157    if (class_loader.is_null()) return false;
 158    if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
 159      return true;
 160    }
 161    return false;
 162 }
 163 
 164 /**
 165  * Returns true if the passed class loader is the extension class loader.
 166  */
 167 bool SystemDictionary::is_ext_class_loader(Handle class_loader) {
 168   if (class_loader.is_null()) {
 169     return false;
 170   }
 171   return (class_loader->klass()->name() == vmSymbols::sun_misc_Launcher_ExtClassLoader());
 172 }
 173 
 174 // ----------------------------------------------------------------------------
 175 // Resolving of classes
 176 
 177 // Forwards to resolve_or_null
 178 
 179 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
 180   Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
 181   if (HAS_PENDING_EXCEPTION || klass == NULL) {
 182     KlassHandle k_h(THREAD, klass);
 183     // can return a null klass
 184     klass = handle_resolution_exception(class_name, throw_error, k_h, THREAD);
 185   }
 186   return klass;
 187 }
 188 
 189 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name,
 190                                                      bool throw_error,
 191                                                      KlassHandle klass_h, TRAPS) {
 192   if (HAS_PENDING_EXCEPTION) {
 193     // If we have a pending exception we forward it to the caller, unless throw_error is true,
 194     // in which case we have to check whether the pending exception is a ClassNotFoundException,
 195     // and if so convert it to a NoClassDefFoundError
 196     // And chain the original ClassNotFoundException
 197     if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
 198       ResourceMark rm(THREAD);
 199       assert(klass_h() == NULL, "Should not have result with exception pending");
 200       Handle e(THREAD, PENDING_EXCEPTION);
 201       CLEAR_PENDING_EXCEPTION;
 202       THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
 203     } else {
 204       return NULL;
 205     }
 206   }
 207   // Class not found, throw appropriate error or exception depending on value of throw_error
 208   if (klass_h() == NULL) {
 209     ResourceMark rm(THREAD);
 210     if (throw_error) {
 211       THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
 212     } else {
 213       THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
 214     }
 215   }
 216   return (Klass*)klass_h();
 217 }
 218 
 219 
 220 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
 221                                            bool throw_error, TRAPS)
 222 {
 223   return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
 224 }
 225 
 226 
 227 // Forwards to resolve_instance_class_or_null
 228 
 229 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
 230   assert(!THREAD->is_Compiler_thread(),
 231          err_msg("can not load classes with compiler thread: class=%s, classloader=%s",
 232                  class_name->as_C_string(),
 233                  class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string()));
 234   if (FieldType::is_array(class_name)) {
 235     return resolve_array_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
 236   } else if (FieldType::is_obj(class_name)) {
 237     ResourceMark rm(THREAD);
 238     // Ignore wrapping L and ;.
 239     TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
 240                                    class_name->utf8_length() - 2, CHECK_NULL);
 241     return resolve_instance_class_or_null(name, class_loader, protection_domain, CHECK_NULL);
 242   } else {
 243     return resolve_instance_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
 244   }
 245 }
 246 
 247 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
 248   return resolve_or_null(class_name, Handle(), Handle(), THREAD);
 249 }
 250 
 251 // Forwards to resolve_instance_class_or_null
 252 
 253 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
 254                                                        Handle class_loader,
 255                                                        Handle protection_domain,
 256                                                        TRAPS) {
 257   assert(FieldType::is_array(class_name), "must be array");
 258   Klass* k = NULL;
 259   FieldArrayInfo fd;
 260   // dimension and object_key in FieldArrayInfo are assigned as a side-effect
 261   // of this call
 262   BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
 263   if (t == T_OBJECT) {
 264     // naked oop "k" is OK here -- we assign back into it
 265     k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
 266                                                          class_loader,
 267                                                          protection_domain,
 268                                                          CHECK_NULL);
 269     if (k != NULL) {
 270       k = k->array_klass(fd.dimension(), CHECK_NULL);
 271     }
 272   } else {
 273     k = Universe::typeArrayKlassObj(t);
 274     k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
 275   }
 276   return k;
 277 }
 278 
 279 
 280 // Must be called for any super-class or super-interface resolution
 281 // during class definition to allow class circularity checking
 282 // super-interface callers:
 283 //    parse_interfaces - for defineClass & jvmtiRedefineClasses
 284 // super-class callers:
 285 //   ClassFileParser - for defineClass & jvmtiRedefineClasses
 286 //   load_shared_class - while loading a class from shared archive
 287 //   resolve_instance_class_or_null:
 288 //     via: handle_parallel_super_load
 289 //      when resolving a class that has an existing placeholder with
 290 //      a saved superclass [i.e. a defineClass is currently in progress]
 291 //      if another thread is trying to resolve the class, it must do
 292 //      super-class checks on its own thread to catch class circularity
 293 // This last call is critical in class circularity checking for cases
 294 // where classloading is delegated to different threads and the
 295 // classloader lock is released.
 296 // Take the case: Base->Super->Base
 297 //   1. If thread T1 tries to do a defineClass of class Base
 298 //    resolve_super_or_fail creates placeholder: T1, Base (super Super)
 299 //   2. resolve_instance_class_or_null does not find SD or placeholder for Super
 300 //    so it tries to load Super
 301 //   3. If we load the class internally, or user classloader uses same thread
 302 //      loadClassFromxxx or defineClass via parseClassFile Super ...
 303 //      3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
 304 //      3.3 resolve_instance_class_or_null Base, finds placeholder for Base
 305 //      3.4 calls resolve_super_or_fail Base
 306 //      3.5 finds T1,Base -> throws class circularity
 307 //OR 4. If T2 tries to resolve Super via defineClass Super ...
 308 //      4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
 309 //      4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
 310 //      4.3 calls resolve_super_or_fail Super in parallel on own thread T2
 311 //      4.4 finds T2, Super -> throws class circularity
 312 // Must be called, even if superclass is null, since this is
 313 // where the placeholder entry is created which claims this
 314 // thread is loading this class/classloader.
 315 Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
 316                                                  Symbol* class_name,
 317                                                  Handle class_loader,
 318                                                  Handle protection_domain,
 319                                                  bool is_superclass,
 320                                                  TRAPS) {
 321   // Double-check, if child class is already loaded, just return super-class,interface
 322   // Don't add a placedholder if already loaded, i.e. already in system dictionary
 323   // Make sure there's a placeholder for the *child* before resolving.
 324   // Used as a claim that this thread is currently loading superclass/classloader
 325   // Used here for ClassCircularity checks and also for heap verification
 326   // (every InstanceKlass in the heap needs to be in the system dictionary
 327   // or have a placeholder).
 328   // Must check ClassCircularity before checking if super class is already loaded
 329   //
 330   // We might not already have a placeholder if this child_name was
 331   // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
 332   // the name of the class might not be known until the stream is actually
 333   // parsed.
 334   // Bugs 4643874, 4715493
 335   // compute_hash can have a safepoint
 336 
 337   ClassLoaderData* loader_data = class_loader_data(class_loader);
 338   unsigned int d_hash = dictionary()->compute_hash(child_name, loader_data);
 339   int d_index = dictionary()->hash_to_index(d_hash);
 340   unsigned int p_hash = placeholders()->compute_hash(child_name, loader_data);
 341   int p_index = placeholders()->hash_to_index(p_hash);
 342   // can't throw error holding a lock
 343   bool child_already_loaded = false;
 344   bool throw_circularity_error = false;
 345   {
 346     MutexLocker mu(SystemDictionary_lock, THREAD);
 347     Klass* childk = find_class(d_index, d_hash, child_name, loader_data);
 348     Klass* quicksuperk;
 349     // to support // loading: if child done loading, just return superclass
 350     // if class_name, & class_loader don't match:
 351     // if initial define, SD update will give LinkageError
 352     // if redefine: compare_class_versions will give HIERARCHY_CHANGED
 353     // so we don't throw an exception here.
 354     // see: nsk redefclass014 & java.lang.instrument Instrument032
 355     if ((childk != NULL ) && (is_superclass) &&
 356        ((quicksuperk = InstanceKlass::cast(childk)->super()) != NULL) &&
 357 
 358          ((quicksuperk->name() == class_name) &&
 359             (quicksuperk->class_loader()  == class_loader()))) {
 360            return quicksuperk;
 361     } else {
 362       PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
 363       if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
 364           throw_circularity_error = true;
 365       }
 366     }
 367     if (!throw_circularity_error) {
 368       PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
 369     }
 370   }
 371   if (throw_circularity_error) {
 372       ResourceMark rm(THREAD);
 373       THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
 374   }
 375 
 376 // java.lang.Object should have been found above
 377   assert(class_name != NULL, "null super class for resolving");
 378   // Resolve the super class or interface, check results on return
 379   Klass* superk = SystemDictionary::resolve_or_null(class_name,
 380                                                  class_loader,
 381                                                  protection_domain,
 382                                                  THREAD);
 383 
 384   KlassHandle superk_h(THREAD, superk);
 385 
 386   // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
 387   // It is no longer necessary to keep the placeholder table alive until update_dictionary
 388   // or error. GC used to walk the placeholder table as strong roots.
 389   // The instanceKlass is kept alive because the class loader is on the stack,
 390   // which keeps the loader_data alive, as well as all instanceKlasses in
 391   // the loader_data. parseClassFile adds the instanceKlass to loader_data.
 392   {
 393     MutexLocker mu(SystemDictionary_lock, THREAD);
 394     placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
 395     SystemDictionary_lock->notify_all();
 396   }
 397   if (HAS_PENDING_EXCEPTION || superk_h() == NULL) {
 398     // can null superk
 399     superk_h = KlassHandle(THREAD, handle_resolution_exception(class_name, true, superk_h, THREAD));
 400   }
 401 
 402   return superk_h();
 403 }
 404 
 405 void SystemDictionary::validate_protection_domain(instanceKlassHandle klass,
 406                                                   Handle class_loader,
 407                                                   Handle protection_domain,
 408                                                   TRAPS) {
 409   if(!has_checkPackageAccess()) return;
 410 
 411   // Now we have to call back to java to check if the initating class has access
 412   JavaValue result(T_VOID);
 413   if (TraceProtectionDomainVerification) {
 414     // Print out trace information
 415     tty->print_cr("Checking package access");
 416     tty->print(" - class loader:      "); class_loader()->print_value_on(tty);      tty->cr();
 417     tty->print(" - protection domain: "); protection_domain()->print_value_on(tty); tty->cr();
 418     tty->print(" - loading:           "); klass()->print_value_on(tty);             tty->cr();
 419   }
 420 
 421   KlassHandle system_loader(THREAD, SystemDictionary::ClassLoader_klass());
 422   JavaCalls::call_special(&result,
 423                          class_loader,
 424                          system_loader,
 425                          vmSymbols::checkPackageAccess_name(),
 426                          vmSymbols::class_protectiondomain_signature(),
 427                          Handle(THREAD, klass->java_mirror()),
 428                          protection_domain,
 429                          THREAD);
 430 
 431   if (TraceProtectionDomainVerification) {
 432     if (HAS_PENDING_EXCEPTION) {
 433       tty->print_cr(" -> DENIED !!!!!!!!!!!!!!!!!!!!!");
 434     } else {
 435      tty->print_cr(" -> granted");
 436     }
 437     tty->cr();
 438   }
 439 
 440   if (HAS_PENDING_EXCEPTION) return;
 441 
 442   // If no exception has been thrown, we have validated the protection domain
 443   // Insert the protection domain of the initiating class into the set.
 444   {
 445     // We recalculate the entry here -- we've called out to java since
 446     // the last time it was calculated.
 447     ClassLoaderData* loader_data = class_loader_data(class_loader);
 448 
 449     Symbol*  kn = klass->name();
 450     unsigned int d_hash = dictionary()->compute_hash(kn, loader_data);
 451     int d_index = dictionary()->hash_to_index(d_hash);
 452 
 453     MutexLocker mu(SystemDictionary_lock, THREAD);
 454     {
 455       // Note that we have an entry, and entries can be deleted only during GC,
 456       // so we cannot allow GC to occur while we're holding this entry.
 457 
 458       // We're using a No_Safepoint_Verifier to catch any place where we
 459       // might potentially do a GC at all.
 460       // Dictionary::do_unloading() asserts that classes in SD are only
 461       // unloaded at a safepoint. Anonymous classes are not in SD.
 462       No_Safepoint_Verifier nosafepoint;
 463       dictionary()->add_protection_domain(d_index, d_hash, klass, loader_data,
 464                                           protection_domain, THREAD);
 465     }
 466   }
 467 }
 468 
 469 // We only get here if this thread finds that another thread
 470 // has already claimed the placeholder token for the current operation,
 471 // but that other thread either never owned or gave up the
 472 // object lock
 473 // Waits on SystemDictionary_lock to indicate placeholder table updated
 474 // On return, caller must recheck placeholder table state
 475 //
 476 // We only get here if
 477 //  1) custom classLoader, i.e. not bootstrap classloader
 478 //  2) UnsyncloadClass not set
 479 //  3) custom classLoader has broken the class loader objectLock
 480 //     so another thread got here in parallel
 481 //
 482 // lockObject must be held.
 483 // Complicated dance due to lock ordering:
 484 // Must first release the classloader object lock to
 485 // allow initial definer to complete the class definition
 486 // and to avoid deadlock
 487 // Reclaim classloader lock object with same original recursion count
 488 // Must release SystemDictionary_lock after notify, since
 489 // class loader lock must be claimed before SystemDictionary_lock
 490 // to prevent deadlocks
 491 //
 492 // The notify allows applications that did an untimed wait() on
 493 // the classloader object lock to not hang.
 494 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
 495   assert_lock_strong(SystemDictionary_lock);
 496 
 497   bool calledholdinglock
 498       = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
 499   assert(calledholdinglock,"must hold lock for notify");
 500   assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
 501   ObjectSynchronizer::notifyall(lockObject, THREAD);
 502   intptr_t recursions =  ObjectSynchronizer::complete_exit(lockObject, THREAD);
 503   SystemDictionary_lock->wait();
 504   SystemDictionary_lock->unlock();
 505   ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
 506   SystemDictionary_lock->lock();
 507 }
 508 
 509 // If the class in is in the placeholder table, class loading is in progress
 510 // For cases where the application changes threads to load classes, it
 511 // is critical to ClassCircularity detection that we try loading
 512 // the superclass on the same thread internally, so we do parallel
 513 // super class loading here.
 514 // This also is critical in cases where the original thread gets stalled
 515 // even in non-circularity situations.
 516 // Note: must call resolve_super_or_fail even if null super -
 517 // to force placeholder entry creation for this class for circularity detection
 518 // Caller must check for pending exception
 519 // Returns non-null Klass* if other thread has completed load
 520 // and we are done,
 521 // If return null Klass* and no pending exception, the caller must load the class
 522 instanceKlassHandle SystemDictionary::handle_parallel_super_load(
 523     Symbol* name, Symbol* superclassname, Handle class_loader,
 524     Handle protection_domain, Handle lockObject, TRAPS) {
 525 
 526   instanceKlassHandle nh = instanceKlassHandle(); // null Handle
 527   ClassLoaderData* loader_data = class_loader_data(class_loader);
 528   unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
 529   int d_index = dictionary()->hash_to_index(d_hash);
 530   unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
 531   int p_index = placeholders()->hash_to_index(p_hash);
 532 
 533   // superk is not used, resolve_super called for circularity check only
 534   // This code is reached in two situations. One if this thread
 535   // is loading the same class twice (e.g. ClassCircularity, or
 536   // java.lang.instrument).
 537   // The second is if another thread started the resolve_super first
 538   // and has not yet finished.
 539   // In both cases the original caller will clean up the placeholder
 540   // entry on error.
 541   Klass* superk = SystemDictionary::resolve_super_or_fail(name,
 542                                                           superclassname,
 543                                                           class_loader,
 544                                                           protection_domain,
 545                                                           true,
 546                                                           CHECK_(nh));
 547 
 548   // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
 549   // Serial class loaders and bootstrap classloader do wait for superclass loads
 550  if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
 551     MutexLocker mu(SystemDictionary_lock, THREAD);
 552     // Check if classloading completed while we were loading superclass or waiting
 553     Klass* check = find_class(d_index, d_hash, name, loader_data);
 554     if (check != NULL) {
 555       // Klass is already loaded, so just return it
 556       return(instanceKlassHandle(THREAD, check));
 557     } else {
 558       return nh;
 559     }
 560   }
 561 
 562   // must loop to both handle other placeholder updates
 563   // and spurious notifications
 564   bool super_load_in_progress = true;
 565   PlaceholderEntry* placeholder;
 566   while (super_load_in_progress) {
 567     MutexLocker mu(SystemDictionary_lock, THREAD);
 568     // Check if classloading completed while we were loading superclass or waiting
 569     Klass* check = find_class(d_index, d_hash, name, loader_data);
 570     if (check != NULL) {
 571       // Klass is already loaded, so just return it
 572       return(instanceKlassHandle(THREAD, check));
 573     } else {
 574       placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
 575       if (placeholder && placeholder->super_load_in_progress() ){
 576         // Before UnsyncloadClass:
 577         // We only get here if the application has released the
 578         // classloader lock when another thread was in the middle of loading a
 579         // superclass/superinterface for this class, and now
 580         // this thread is also trying to load this class.
 581         // To minimize surprises, the first thread that started to
 582         // load a class should be the one to complete the loading
 583         // with the classfile it initially expected.
 584         // This logic has the current thread wait once it has done
 585         // all the superclass/superinterface loading it can, until
 586         // the original thread completes the class loading or fails
 587         // If it completes we will use the resulting InstanceKlass
 588         // which we will find below in the systemDictionary.
 589         // We also get here for parallel bootstrap classloader
 590         if (class_loader.is_null()) {
 591           SystemDictionary_lock->wait();
 592         } else {
 593           double_lock_wait(lockObject, THREAD);
 594         }
 595       } else {
 596         // If not in SD and not in PH, other thread's load must have failed
 597         super_load_in_progress = false;
 598       }
 599     }
 600   }
 601   return (nh);
 602 }
 603 
 604 
 605 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
 606                                                         Handle class_loader,
 607                                                         Handle protection_domain,
 608                                                         TRAPS) {
 609   assert(name != NULL && !FieldType::is_array(name) &&
 610          !FieldType::is_obj(name), "invalid class name");
 611 
 612   Ticks class_load_start_time = Ticks::now();
 613 
 614   // Fix for 4474172; see evaluation for more details
 615   class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
 616   ClassLoaderData *loader_data = register_loader(class_loader, CHECK_NULL);
 617 
 618   // Do lookup to see if class already exist and the protection domain
 619   // has the right access
 620   // This call uses find which checks protection domain already matches
 621   // All subsequent calls use find_class, and set has_loaded_class so that
 622   // before we return a result we call out to java to check for valid protection domain
 623   // to allow returning the Klass* and add it to the pd_set if it is valid
 624   unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
 625   int d_index = dictionary()->hash_to_index(d_hash);
 626   Klass* probe = dictionary()->find(d_index, d_hash, name, loader_data,
 627                                       protection_domain, THREAD);
 628   if (probe != NULL) return probe;
 629 
 630 
 631   // Non-bootstrap class loaders will call out to class loader and
 632   // define via jvm/jni_DefineClass which will acquire the
 633   // class loader object lock to protect against multiple threads
 634   // defining the class in parallel by accident.
 635   // This lock must be acquired here so the waiter will find
 636   // any successful result in the SystemDictionary and not attempt
 637   // the define
 638   // ParallelCapable Classloaders and the bootstrap classloader,
 639   // or all classloaders with UnsyncloadClass do not acquire lock here
 640   bool DoObjectLock = true;
 641   if (is_parallelCapable(class_loader)) {
 642     DoObjectLock = false;
 643   }
 644 
 645   unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
 646   int p_index = placeholders()->hash_to_index(p_hash);
 647 
 648   // Class is not in SystemDictionary so we have to do loading.
 649   // Make sure we are synchronized on the class loader before we proceed
 650   Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
 651   check_loader_lock_contention(lockObject, THREAD);
 652   ObjectLocker ol(lockObject, THREAD, DoObjectLock);
 653 
 654   // Check again (after locking) if class already exist in SystemDictionary
 655   bool class_has_been_loaded   = false;
 656   bool super_load_in_progress  = false;
 657   bool havesupername = false;
 658   instanceKlassHandle k;
 659   PlaceholderEntry* placeholder;
 660   Symbol* superclassname = NULL;
 661 
 662   {
 663     MutexLocker mu(SystemDictionary_lock, THREAD);
 664     Klass* check = find_class(d_index, d_hash, name, loader_data);
 665     if (check != NULL) {
 666       // Klass is already loaded, so just return it
 667       class_has_been_loaded = true;
 668       k = instanceKlassHandle(THREAD, check);
 669     } else {
 670       placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
 671       if (placeholder && placeholder->super_load_in_progress()) {
 672          super_load_in_progress = true;
 673          if (placeholder->havesupername() == true) {
 674            superclassname = placeholder->supername();
 675            havesupername = true;
 676          }
 677       }
 678     }
 679   }
 680 
 681   // If the class is in the placeholder table, class loading is in progress
 682   if (super_load_in_progress && havesupername==true) {
 683     k = SystemDictionary::handle_parallel_super_load(name, superclassname,
 684         class_loader, protection_domain, lockObject, THREAD);
 685     if (HAS_PENDING_EXCEPTION) {
 686       return NULL;
 687     }
 688     if (!k.is_null()) {
 689       class_has_been_loaded = true;
 690     }
 691   }
 692 
 693   bool throw_circularity_error = false;
 694   if (!class_has_been_loaded) {
 695     bool load_instance_added = false;
 696 
 697     // add placeholder entry to record loading instance class
 698     // Five cases:
 699     // All cases need to prevent modifying bootclasssearchpath
 700     // in parallel with a classload of same classname
 701     // Redefineclasses uses existence of the placeholder for the duration
 702     // of the class load to prevent concurrent redefinition of not completely
 703     // defined classes.
 704     // case 1. traditional classloaders that rely on the classloader object lock
 705     //   - no other need for LOAD_INSTANCE
 706     // case 2. traditional classloaders that break the classloader object lock
 707     //    as a deadlock workaround. Detection of this case requires that
 708     //    this check is done while holding the classloader object lock,
 709     //    and that lock is still held when calling classloader's loadClass.
 710     //    For these classloaders, we ensure that the first requestor
 711     //    completes the load and other requestors wait for completion.
 712     // case 3. UnsyncloadClass - don't use objectLocker
 713     //    With this flag, we allow parallel classloading of a
 714     //    class/classloader pair
 715     // case4. Bootstrap classloader - don't own objectLocker
 716     //    This classloader supports parallelism at the classloader level,
 717     //    but only allows a single load of a class/classloader pair.
 718     //    No performance benefit and no deadlock issues.
 719     // case 5. parallelCapable user level classloaders - without objectLocker
 720     //    Allow parallel classloading of a class/classloader pair
 721 
 722     {
 723       MutexLocker mu(SystemDictionary_lock, THREAD);
 724       if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
 725         PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
 726         if (oldprobe) {
 727           // only need check_seen_thread once, not on each loop
 728           // 6341374 java/lang/Instrument with -Xcomp
 729           if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
 730             throw_circularity_error = true;
 731           } else {
 732             // case 1: traditional: should never see load_in_progress.
 733             while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
 734 
 735               // case 4: bootstrap classloader: prevent futile classloading,
 736               // wait on first requestor
 737               if (class_loader.is_null()) {
 738                 SystemDictionary_lock->wait();
 739               } else {
 740               // case 2: traditional with broken classloader lock. wait on first
 741               // requestor.
 742                 double_lock_wait(lockObject, THREAD);
 743               }
 744               // Check if classloading completed while we were waiting
 745               Klass* check = find_class(d_index, d_hash, name, loader_data);
 746               if (check != NULL) {
 747                 // Klass is already loaded, so just return it
 748                 k = instanceKlassHandle(THREAD, check);
 749                 class_has_been_loaded = true;
 750               }
 751               // check if other thread failed to load and cleaned up
 752               oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
 753             }
 754           }
 755         }
 756       }
 757       // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
 758       // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try
 759       // LOAD_INSTANCE in parallel
 760 
 761       if (!throw_circularity_error && !class_has_been_loaded) {
 762         PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
 763         load_instance_added = true;
 764         // For class loaders that do not acquire the classloader object lock,
 765         // if they did not catch another thread holding LOAD_INSTANCE,
 766         // need a check analogous to the acquire ObjectLocker/find_class
 767         // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
 768         // one final check if the load has already completed
 769         // class loaders holding the ObjectLock shouldn't find the class here
 770         Klass* check = find_class(d_index, d_hash, name, loader_data);
 771         if (check != NULL) {
 772         // Klass is already loaded, so return it after checking/adding protection domain
 773           k = instanceKlassHandle(THREAD, check);
 774           class_has_been_loaded = true;
 775         }
 776       }
 777     }
 778 
 779     // must throw error outside of owning lock
 780     if (throw_circularity_error) {
 781       assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
 782       ResourceMark rm(THREAD);
 783       THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
 784     }
 785 
 786     if (!class_has_been_loaded) {
 787 
 788       // Do actual loading
 789       k = load_instance_class(name, class_loader, THREAD);
 790 
 791       // For UnsyncloadClass only
 792       // If they got a linkageError, check if a parallel class load succeeded.
 793       // If it did, then for bytecode resolution the specification requires
 794       // that we return the same result we did for the other thread, i.e. the
 795       // successfully loaded InstanceKlass
 796       // Should not get here for classloaders that support parallelism
 797       // with the new cleaner mechanism, even with AllowParallelDefineClass
 798       // Bootstrap goes through here to allow for an extra guarantee check
 799       if (UnsyncloadClass || (class_loader.is_null())) {
 800         if (k.is_null() && HAS_PENDING_EXCEPTION
 801           && PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass())) {
 802           MutexLocker mu(SystemDictionary_lock, THREAD);
 803           Klass* check = find_class(d_index, d_hash, name, loader_data);
 804           if (check != NULL) {
 805             // Klass is already loaded, so just use it
 806             k = instanceKlassHandle(THREAD, check);
 807             CLEAR_PENDING_EXCEPTION;
 808             guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?");
 809           }
 810         }
 811       }
 812 
 813       // If everything was OK (no exceptions, no null return value), and
 814       // class_loader is NOT the defining loader, do a little more bookkeeping.
 815       if (!HAS_PENDING_EXCEPTION && !k.is_null() &&
 816         k->class_loader() != class_loader()) {
 817 
 818         check_constraints(d_index, d_hash, k, class_loader, false, THREAD);
 819 
 820         // Need to check for a PENDING_EXCEPTION again; check_constraints
 821         // can throw and doesn't use the CHECK macro.
 822         if (!HAS_PENDING_EXCEPTION) {
 823           { // Grabbing the Compile_lock prevents systemDictionary updates
 824             // during compilations.
 825             MutexLocker mu(Compile_lock, THREAD);
 826             update_dictionary(d_index, d_hash, p_index, p_hash,
 827                               k, class_loader, THREAD);
 828           }
 829 
 830           if (JvmtiExport::should_post_class_load()) {
 831             Thread *thread = THREAD;
 832             assert(thread->is_Java_thread(), "thread->is_Java_thread()");
 833             JvmtiExport::post_class_load((JavaThread *) thread, k());
 834           }
 835         }
 836       }
 837     } // load_instance_class loop
 838 
 839     if (load_instance_added == true) {
 840       // clean up placeholder entries for LOAD_INSTANCE success or error
 841       // This brackets the SystemDictionary updates for both defining
 842       // and initiating loaders
 843       MutexLocker mu(SystemDictionary_lock, THREAD);
 844       placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
 845       SystemDictionary_lock->notify_all();
 846     }
 847   }
 848 
 849   if (HAS_PENDING_EXCEPTION || k.is_null()) {
 850     return NULL;
 851   }
 852 
 853   post_class_load_event(class_load_start_time, k, class_loader);
 854 
 855 #ifdef ASSERT
 856   {
 857     ClassLoaderData* loader_data = k->class_loader_data();
 858     MutexLocker mu(SystemDictionary_lock, THREAD);
 859     Klass* kk = find_class(name, loader_data);
 860     assert(kk == k(), "should be present in dictionary");
 861   }
 862 #endif
 863 
 864   // return if the protection domain in NULL
 865   if (protection_domain() == NULL) return k();
 866 
 867   // Check the protection domain has the right access
 868   {
 869     MutexLocker mu(SystemDictionary_lock, THREAD);
 870     // Note that we have an entry, and entries can be deleted only during GC,
 871     // so we cannot allow GC to occur while we're holding this entry.
 872     // We're using a No_Safepoint_Verifier to catch any place where we
 873     // might potentially do a GC at all.
 874     // Dictionary::do_unloading() asserts that classes in SD are only
 875     // unloaded at a safepoint. Anonymous classes are not in SD.
 876     No_Safepoint_Verifier nosafepoint;
 877     if (dictionary()->is_valid_protection_domain(d_index, d_hash, name,
 878                                                  loader_data,
 879                                                  protection_domain)) {
 880       return k();
 881     }
 882   }
 883 
 884   // Verify protection domain. If it fails an exception is thrown
 885   validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
 886 
 887   return k();
 888 }
 889 
 890 
 891 // This routine does not lock the system dictionary.
 892 //
 893 // Since readers don't hold a lock, we must make sure that system
 894 // dictionary entries are only removed at a safepoint (when only one
 895 // thread is running), and are added to in a safe way (all links must
 896 // be updated in an MT-safe manner).
 897 //
 898 // Callers should be aware that an entry could be added just after
 899 // _dictionary->bucket(index) is read here, so the caller will not see
 900 // the new entry.
 901 
 902 Klass* SystemDictionary::find(Symbol* class_name,
 903                               Handle class_loader,
 904                               Handle protection_domain,
 905                               TRAPS) {
 906 
 907   // The result of this call should be consistent with the result
 908   // of the call to resolve_instance_class_or_null().
 909   // See evaluation 6790209 and 4474172 for more details.
 910   class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
 911   ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
 912 
 913   if (loader_data == NULL) {
 914     // If the ClassLoaderData has not been setup,
 915     // then the class loader has no entries in the dictionary.
 916     return NULL;
 917   }
 918 
 919   unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
 920   int d_index = dictionary()->hash_to_index(d_hash);
 921 
 922   {
 923     // Note that we have an entry, and entries can be deleted only during GC,
 924     // so we cannot allow GC to occur while we're holding this entry.
 925     // We're using a No_Safepoint_Verifier to catch any place where we
 926     // might potentially do a GC at all.
 927     // Dictionary::do_unloading() asserts that classes in SD are only
 928     // unloaded at a safepoint. Anonymous classes are not in SD.
 929     No_Safepoint_Verifier nosafepoint;
 930     return dictionary()->find(d_index, d_hash, class_name, loader_data,
 931                               protection_domain, THREAD);
 932   }
 933 }
 934 
 935 
 936 // Look for a loaded instance or array klass by name.  Do not do any loading.
 937 // return NULL in case of error.
 938 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
 939                                                       Handle class_loader,
 940                                                       Handle protection_domain,
 941                                                       TRAPS) {
 942   Klass* k = NULL;
 943   assert(class_name != NULL, "class name must be non NULL");
 944 
 945   if (FieldType::is_array(class_name)) {
 946     // The name refers to an array.  Parse the name.
 947     // dimension and object_key in FieldArrayInfo are assigned as a
 948     // side-effect of this call
 949     FieldArrayInfo fd;
 950     BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
 951     if (t != T_OBJECT) {
 952       k = Universe::typeArrayKlassObj(t);
 953     } else {
 954       k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
 955     }
 956     if (k != NULL) {
 957       k = k->array_klass_or_null(fd.dimension());
 958     }
 959   } else {
 960     k = find(class_name, class_loader, protection_domain, THREAD);
 961   }
 962   return k;
 963 }
 964 
 965 // Note: this method is much like resolve_from_stream, but
 966 // updates no supplemental data structures.
 967 // TODO consolidate the two methods with a helper routine?
 968 Klass* SystemDictionary::parse_stream(Symbol* class_name,
 969                                       Handle class_loader,
 970                                       Handle protection_domain,
 971                                       ClassFileStream* st,
 972                                       KlassHandle host_klass,
 973                                       GrowableArray<Handle>* cp_patches,
 974                                       TRAPS) {
 975   TempNewSymbol parsed_name = NULL;
 976 
 977   Ticks class_load_start_time = Ticks::now();
 978 
 979   ClassLoaderData* loader_data;
 980   if (host_klass.not_null()) {
 981     // Create a new CLD for anonymous class, that uses the same class loader
 982     // as the host_klass
 983     guarantee(host_klass->class_loader() == class_loader(), "should be the same");
 984     guarantee(!DumpSharedSpaces, "must not create anonymous classes when dumping");
 985     loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader(), CHECK_NULL);
 986     loader_data->record_dependency(host_klass(), CHECK_NULL);
 987   } else {
 988     loader_data = ClassLoaderData::class_loader_data(class_loader());
 989   }
 990 
 991   // Parse the stream. Note that we do this even though this klass might
 992   // already be present in the SystemDictionary, otherwise we would not
 993   // throw potential ClassFormatErrors.
 994   //
 995   // Note: "name" is updated.
 996 
 997   instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
 998                                                              loader_data,
 999                                                              protection_domain,
1000                                                              host_klass,
1001                                                              cp_patches,
1002                                                              parsed_name,
1003                                                              true,
1004                                                              THREAD);
1005 
1006 
1007   if (host_klass.not_null() && k.not_null()) {
1008     // If it's anonymous, initialize it now, since nobody else will.
1009 
1010     {
1011       MutexLocker mu_r(Compile_lock, THREAD);
1012 
1013       // Add to class hierarchy, initialize vtables, and do possible
1014       // deoptimizations.
1015       add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1016 
1017       // But, do not add to system dictionary.
1018 
1019       // compiled code dependencies need to be validated anyway
1020       notice_modification();
1021     }
1022 
1023     // Rewrite and patch constant pool here.
1024     k->link_class(CHECK_NULL);
1025     if (cp_patches != NULL) {
1026       k->constants()->patch_resolved_references(cp_patches);
1027     }
1028     k->eager_initialize(CHECK_NULL);
1029 
1030     // notify jvmti
1031     if (JvmtiExport::should_post_class_load()) {
1032         assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1033         JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1034     }
1035 
1036     post_class_load_event(class_load_start_time, k, class_loader);
1037   }
1038   assert(host_klass.not_null() || cp_patches == NULL,
1039          "cp_patches only found with host_klass");
1040 
1041   return k();
1042 }
1043 
1044 // Add a klass to the system from a stream (called by jni_DefineClass and
1045 // JVM_DefineClass).
1046 // Note: class_name can be NULL. In that case we do not know the name of
1047 // the class until we have parsed the stream.
1048 
1049 Klass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1050                                              Handle class_loader,
1051                                              Handle protection_domain,
1052                                              ClassFileStream* st,
1053                                              bool verify,
1054                                              TRAPS) {
1055 
1056   // Classloaders that support parallelism, e.g. bootstrap classloader,
1057   // or all classloaders with UnsyncloadClass do not acquire lock here
1058   bool DoObjectLock = true;
1059   if (is_parallelCapable(class_loader)) {
1060     DoObjectLock = false;
1061   }
1062 
1063   ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL);
1064 
1065   // Make sure we are synchronized on the class loader before we proceed
1066   Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1067   check_loader_lock_contention(lockObject, THREAD);
1068   ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1069 
1070   TempNewSymbol parsed_name = NULL;
1071 
1072   // Parse the stream. Note that we do this even though this klass might
1073   // already be present in the SystemDictionary, otherwise we would not
1074   // throw potential ClassFormatErrors.
1075   //
1076   // Note: "name" is updated.
1077 
1078   instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
1079                                                              loader_data,
1080                                                              protection_domain,
1081                                                              parsed_name,
1082                                                              verify,
1083                                                              THREAD);
1084 
1085   const char* pkg = "java/";
1086   if (!HAS_PENDING_EXCEPTION &&
1087       !class_loader.is_null() &&
1088       parsed_name != NULL &&
1089       !strncmp((const char*)parsed_name->bytes(), pkg, strlen(pkg))) {
1090     // It is illegal to define classes in the "java." package from
1091     // JVM_DefineClass or jni_DefineClass unless you're the bootclassloader
1092     ResourceMark rm(THREAD);
1093     char* name = parsed_name->as_C_string();
1094     char* index = strrchr(name, '/');
1095     *index = '\0'; // chop to just the package name
1096     while ((index = strchr(name, '/')) != NULL) {
1097       *index = '.'; // replace '/' with '.' in package name
1098     }
1099     const char* fmt = "Prohibited package name: %s";
1100     size_t len = strlen(fmt) + strlen(name);
1101     char* message = NEW_RESOURCE_ARRAY(char, len);
1102     jio_snprintf(message, len, fmt, name);
1103     Exceptions::_throw_msg(THREAD_AND_LOCATION,
1104       vmSymbols::java_lang_SecurityException(), message);
1105   }
1106 
1107   if (!HAS_PENDING_EXCEPTION) {
1108     assert(parsed_name != NULL, "Sanity");
1109     assert(class_name == NULL || class_name == parsed_name, "name mismatch");
1110     // Verification prevents us from creating names with dots in them, this
1111     // asserts that that's the case.
1112     assert(is_internal_format(parsed_name),
1113            "external class name format used internally");
1114 
1115     // Add class just loaded
1116     // If a class loader supports parallel classloading handle parallel define requests
1117     // find_or_define_instance_class may return a different InstanceKlass
1118     if (is_parallelCapable(class_loader)) {
1119       k = find_or_define_instance_class(class_name, class_loader, k, THREAD);
1120     } else {
1121       define_instance_class(k, THREAD);
1122     }
1123   }
1124 
1125   // Make sure we have an entry in the SystemDictionary on success
1126   debug_only( {
1127     if (!HAS_PENDING_EXCEPTION) {
1128       assert(parsed_name != NULL, "parsed_name is still null?");
1129       Symbol*  h_name    = k->name();
1130       ClassLoaderData *defining_loader_data = k->class_loader_data();
1131 
1132       MutexLocker mu(SystemDictionary_lock, THREAD);
1133 
1134       Klass* check = find_class(parsed_name, loader_data);
1135       assert(check == k(), "should be present in the dictionary");
1136 
1137       Klass* check2 = find_class(h_name, defining_loader_data);
1138       assert(check == check2, "name inconsistancy in SystemDictionary");
1139     }
1140   } );
1141 
1142   return k();
1143 }
1144 
1145 #if INCLUDE_CDS
1146 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1147                                              int number_of_entries) {
1148   assert(length == _nof_buckets * sizeof(HashtableBucket<mtClass>),
1149          "bad shared dictionary size.");
1150   _shared_dictionary = new Dictionary(_nof_buckets, t, number_of_entries);
1151 }
1152 
1153 
1154 // If there is a shared dictionary, then find the entry for the
1155 // given shared system class, if any.
1156 
1157 Klass* SystemDictionary::find_shared_class(Symbol* class_name) {
1158   if (shared_dictionary() != NULL) {
1159     unsigned int d_hash = shared_dictionary()->compute_hash(class_name, NULL);
1160     int d_index = shared_dictionary()->hash_to_index(d_hash);
1161 
1162     return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1163   } else {
1164     return NULL;
1165   }
1166 }
1167 
1168 
1169 // Load a class from the shared spaces (found through the shared system
1170 // dictionary).  Force the superclass and all interfaces to be loaded.
1171 // Update the class definition to include sibling classes and no
1172 // subclasses (yet).  [Classes in the shared space are not part of the
1173 // object hierarchy until loaded.]
1174 
1175 instanceKlassHandle SystemDictionary::load_shared_class(
1176                  Symbol* class_name, Handle class_loader, TRAPS) {
1177   instanceKlassHandle ik (THREAD, find_shared_class(class_name));
1178   // Make sure we only return the boot class for the NULL classloader.
1179   if (ik.not_null() &&
1180       SharedClassUtil::is_shared_boot_class(ik()) && class_loader.is_null()) {
1181     Handle protection_domain;
1182     return load_shared_class(ik, class_loader, protection_domain, THREAD);
1183   }
1184   return instanceKlassHandle();
1185 }
1186 
1187 instanceKlassHandle SystemDictionary::load_shared_class(instanceKlassHandle ik,
1188                                                         Handle class_loader,
1189                                                         Handle protection_domain, TRAPS) {
1190   if (ik.not_null()) {
1191     instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1192     Symbol* class_name = ik->name();
1193 
1194     // Found the class, now load the superclass and interfaces.  If they
1195     // are shared, add them to the main system dictionary and reset
1196     // their hierarchy references (supers, subs, and interfaces).
1197 
1198     if (ik->super() != NULL) {
1199       Symbol*  cn = ik->super()->name();
1200       resolve_super_or_fail(class_name, cn,
1201                             class_loader, protection_domain, true, CHECK_(nh));
1202     }
1203 
1204     Array<Klass*>* interfaces = ik->local_interfaces();
1205     int num_interfaces = interfaces->length();
1206     for (int index = 0; index < num_interfaces; index++) {
1207       Klass* k = interfaces->at(index);
1208 
1209       // Note: can not use InstanceKlass::cast here because
1210       // interfaces' InstanceKlass's C++ vtbls haven't been
1211       // reinitialized yet (they will be once the interface classes
1212       // are loaded)
1213       Symbol*  name  = k->name();
1214       resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_(nh));
1215     }
1216 
1217     // Adjust methods to recover missing data.  They need addresses for
1218     // interpreter entry points and their default native method address
1219     // must be reset.
1220 
1221     // Updating methods must be done under a lock so multiple
1222     // threads don't update these in parallel
1223     //
1224     // Shared classes are all currently loaded by either the bootstrap or
1225     // internal parallel class loaders, so this will never cause a deadlock
1226     // on a custom class loader lock.
1227 
1228     ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1229     {
1230       Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1231       check_loader_lock_contention(lockObject, THREAD);
1232       ObjectLocker ol(lockObject, THREAD, true);
1233       ik->restore_unshareable_info(loader_data, protection_domain, CHECK_(nh));
1234     }
1235 
1236     if (TraceClassLoading) {
1237       ResourceMark rm;
1238       tty->print("[Loaded %s", ik->external_name());
1239       tty->print(" from shared objects file");
1240       if (class_loader.not_null()) {
1241         tty->print(" by %s", loader_data->loader_name());
1242       }
1243       tty->print_cr("]");
1244     }
1245 
1246 #if INCLUDE_CDS
1247     if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1248       // Only dump the classes that can be stored into CDS archive
1249       if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1250         ResourceMark rm(THREAD);
1251         classlist_file->print_cr("%s", ik->name()->as_C_string());
1252         classlist_file->flush();
1253       }
1254     }
1255 #endif
1256 
1257     // notify a class loaded from shared object
1258     ClassLoadingService::notify_class_loaded(InstanceKlass::cast(ik()),
1259                                              true /* shared class */);
1260   }
1261   return ik;
1262 }
1263 #endif
1264 
1265 instanceKlassHandle SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1266   instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1267   if (class_loader.is_null()) {
1268 
1269     // Search the shared system dictionary for classes preloaded into the
1270     // shared spaces.
1271     instanceKlassHandle k;
1272     {
1273 #if INCLUDE_CDS
1274       PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1275       k = load_shared_class(class_name, class_loader, THREAD);
1276 #endif
1277     }
1278 
1279     if (k.is_null()) {
1280       // Use VM class loader
1281       PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1282       k = ClassLoader::load_classfile(class_name, CHECK_(nh));
1283     }
1284 
1285     // find_or_define_instance_class may return a different InstanceKlass
1286     if (!k.is_null()) {
1287       k = find_or_define_instance_class(class_name, class_loader, k, CHECK_(nh));
1288     }
1289     return k;
1290   } else {
1291     // Use user specified class loader to load class. Call loadClass operation on class_loader.
1292     ResourceMark rm(THREAD);
1293 
1294     assert(THREAD->is_Java_thread(), "must be a JavaThread");
1295     JavaThread* jt = (JavaThread*) THREAD;
1296 
1297     PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1298                                ClassLoader::perf_app_classload_selftime(),
1299                                ClassLoader::perf_app_classload_count(),
1300                                jt->get_thread_stat()->perf_recursion_counts_addr(),
1301                                jt->get_thread_stat()->perf_timers_addr(),
1302                                PerfClassTraceTime::CLASS_LOAD);
1303 
1304     Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nh));
1305     // Translate to external class name format, i.e., convert '/' chars to '.'
1306     Handle string = java_lang_String::externalize_classname(s, CHECK_(nh));
1307 
1308     JavaValue result(T_OBJECT);
1309 
1310     KlassHandle spec_klass (THREAD, SystemDictionary::ClassLoader_klass());
1311 
1312     // Call public unsynchronized loadClass(String) directly for all class loaders
1313     // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will
1314     // acquire a class-name based lock rather than the class loader object lock.
1315     // JDK < 7 already acquire the class loader lock in loadClass(String, boolean),
1316     // so the call to loadClassInternal() was not required.
1317     //
1318     // UnsyncloadClass flag means both call loadClass(String) and do
1319     // not acquire the class loader lock even for class loaders that are
1320     // not parallelCapable. This was a risky transitional
1321     // flag for diagnostic purposes only. It is risky to call
1322     // custom class loaders without synchronization.
1323     // WARNING If a custom class loader does NOT synchronizer findClass, or callers of
1324     // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field.
1325     // Do NOT assume this will be supported in future releases.
1326     //
1327     // Added MustCallLoadClassInternal in case we discover in the field
1328     // a customer that counts on this call
1329     if (MustCallLoadClassInternal && has_loadClassInternal()) {
1330       JavaCalls::call_special(&result,
1331                               class_loader,
1332                               spec_klass,
1333                               vmSymbols::loadClassInternal_name(),
1334                               vmSymbols::string_class_signature(),
1335                               string,
1336                               CHECK_(nh));
1337     } else {
1338       JavaCalls::call_virtual(&result,
1339                               class_loader,
1340                               spec_klass,
1341                               vmSymbols::loadClass_name(),
1342                               vmSymbols::string_class_signature(),
1343                               string,
1344                               CHECK_(nh));
1345     }
1346 
1347     assert(result.get_type() == T_OBJECT, "just checking");
1348     oop obj = (oop) result.get_jobject();
1349 
1350     // Primitive classes return null since forName() can not be
1351     // used to obtain any of the Class objects representing primitives or void
1352     if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1353       instanceKlassHandle k =
1354                 instanceKlassHandle(THREAD, java_lang_Class::as_Klass(obj));
1355       // For user defined Java class loaders, check that the name returned is
1356       // the same as that requested.  This check is done for the bootstrap
1357       // loader when parsing the class file.
1358       if (class_name == k->name()) {
1359         return k;
1360       }
1361     }
1362     // Class is not found or has the wrong name, return NULL
1363     return nh;
1364   }
1365 }
1366 
1367 void SystemDictionary::define_instance_class(instanceKlassHandle k, TRAPS) {
1368 
1369   ClassLoaderData* loader_data = k->class_loader_data();
1370   Handle class_loader_h(THREAD, loader_data->class_loader());
1371 
1372   for (uintx it = 0; it < GCExpandToAllocateDelayMillis; it++){}
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   Universe::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   // First, mark for unload all ClassLoaderData referencing a dead class loader.
1696   bool unloading_occurred = ClassLoaderDataGraph::do_unloading(is_alive);
1697   if (unloading_occurred) {
1698     dictionary()->do_unloading();
1699     constraints()->purge_loader_constraints();
1700     resolution_errors()->purge_resolution_errors();
1701   }
1702   // Oops referenced by the system dictionary may get unreachable independently
1703   // of the class loader (eg. cached protection domain oops). So we need to
1704   // explicitly unlink them here instead of in Dictionary::do_unloading.
1705   dictionary()->unlink(is_alive);
1706 #ifdef ASSERT
1707   VerifySDReachableAndLiveClosure cl(is_alive);
1708   dictionary()->oops_do(&cl);
1709 #endif
1710   return unloading_occurred;
1711 }
1712 
1713 void SystemDictionary::roots_oops_do(OopClosure* strong, OopClosure* weak) {
1714   strong->do_oop(&_java_system_loader);
1715   strong->do_oop(&_system_loader_lock_obj);
1716   CDS_ONLY(SystemDictionaryShared::roots_oops_do(strong);)
1717 
1718   // Adjust dictionary
1719   dictionary()->roots_oops_do(strong, weak);
1720 
1721   // Visit extra methods
1722   invoke_method_table()->oops_do(strong);
1723 }
1724 
1725 void SystemDictionary::oops_do(OopClosure* f) {
1726   f->do_oop(&_java_system_loader);
1727   f->do_oop(&_system_loader_lock_obj);
1728   CDS_ONLY(SystemDictionaryShared::oops_do(f);)
1729 
1730   // Adjust dictionary
1731   dictionary()->oops_do(f);
1732 
1733   // Visit extra methods
1734   invoke_method_table()->oops_do(f);
1735 }
1736 
1737 // Extended Class redefinition support.
1738 // If one of these classes is replaced, we need to replace it in these places.
1739 // KlassClosure::do_klass should take the address of a class but we can
1740 // change that later.
1741 void SystemDictionary::preloaded_classes_do(KlassClosure* f) {
1742   for (int k = (int)FIRST_WKID; k < (int)WKID_LIMIT; k++) {
1743     f->do_klass(_well_known_klasses[k]);
1744   }
1745 
1746   {
1747     for (int i = 0; i < T_VOID+1; i++) {
1748       if (_box_klasses[i] != NULL) {
1749         assert(i >= T_BOOLEAN, "checking");
1750         f->do_klass(_box_klasses[i]);
1751       }
1752     }
1753   }
1754 
1755   FilteredFieldsMap::classes_do(f);
1756 }
1757 
1758 void SystemDictionary::lazily_loaded_classes_do(KlassClosure* f) {
1759   f->do_klass(_abstract_ownable_synchronizer_klass);
1760 }
1761 
1762 // Just the classes from defining class loaders
1763 // Don't iterate over placeholders
1764 void SystemDictionary::classes_do(void f(Klass*)) {
1765   dictionary()->classes_do(f);
1766 }
1767 
1768 // Added for initialize_itable_for_klass
1769 //   Just the classes from defining class loaders
1770 // Don't iterate over placeholders
1771 void SystemDictionary::classes_do(void f(Klass*, TRAPS), TRAPS) {
1772   dictionary()->classes_do(f, CHECK);
1773 }
1774 
1775 //   All classes, and their class loaders
1776 // Don't iterate over placeholders
1777 void SystemDictionary::classes_do(void f(Klass*, ClassLoaderData*)) {
1778   dictionary()->classes_do(f);
1779 }
1780 
1781 void SystemDictionary::placeholders_do(void f(Symbol*)) {
1782   placeholders()->entries_do(f);
1783 }
1784 
1785 void SystemDictionary::methods_do(void f(Method*)) {
1786   dictionary()->methods_do(f);
1787   invoke_method_table()->methods_do(f);
1788 }
1789 
1790 void SystemDictionary::remove_classes_in_error_state() {
1791   dictionary()->remove_classes_in_error_state();
1792 }
1793 
1794 // ----------------------------------------------------------------------------
1795 // Lazily load klasses
1796 
1797 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
1798   // if multiple threads calling this function, only one thread will load
1799   // the class.  The other threads will find the loaded version once the
1800   // class is loaded.
1801   Klass* aos = _abstract_ownable_synchronizer_klass;
1802   if (aos == NULL) {
1803     Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
1804     // Force a fence to prevent any read before the write completes
1805     OrderAccess::fence();
1806     _abstract_ownable_synchronizer_klass = k;
1807   }
1808 }
1809 
1810 // ----------------------------------------------------------------------------
1811 // Initialization
1812 
1813 void SystemDictionary::initialize(TRAPS) {
1814   // Allocate arrays
1815   assert(dictionary() == NULL,
1816          "SystemDictionary should only be initialized once");
1817   _sdgeneration        = 0;
1818   _dictionary          = new Dictionary(calculate_systemdictionary_size(PredictedLoadedClassCount));
1819   _placeholders        = new PlaceholderTable(_nof_buckets);
1820   _number_of_modifications = 0;
1821   _loader_constraints  = new LoaderConstraintTable(_loader_constraint_size);
1822   _resolution_errors   = new ResolutionErrorTable(_resolution_error_size);
1823   _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
1824 
1825   // Allocate private object used as system class loader lock
1826   _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
1827   // Initialize basic classes
1828   initialize_preloaded_classes(CHECK);
1829 }
1830 
1831 // Compact table of directions on the initialization of klasses:
1832 static const short wk_init_info[] = {
1833   #define WK_KLASS_INIT_INFO(name, symbol, option) \
1834     ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
1835           << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
1836       | (int)SystemDictionary::option ),
1837   WK_KLASSES_DO(WK_KLASS_INIT_INFO)
1838   #undef WK_KLASS_INIT_INFO
1839   0
1840 };
1841 
1842 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
1843   assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1844   int  info = wk_init_info[id - FIRST_WKID];
1845   int  sid  = (info >> CEIL_LG_OPTION_LIMIT);
1846   Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
1847   Klass**    klassp = &_well_known_klasses[id];
1848   bool must_load = (init_opt < SystemDictionary::Opt);
1849   if ((*klassp) == NULL) {
1850     if (must_load) {
1851       (*klassp) = resolve_or_fail(symbol, true, CHECK_0); // load required class
1852     } else {
1853       (*klassp) = resolve_or_null(symbol,       CHECK_0); // load optional klass
1854     }
1855   }
1856   return ((*klassp) != NULL);
1857 }
1858 
1859 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
1860   assert((int)start_id <= (int)limit_id, "IDs are out of order!");
1861   for (int id = (int)start_id; id < (int)limit_id; id++) {
1862     assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1863     int info = wk_init_info[id - FIRST_WKID];
1864     int sid  = (info >> CEIL_LG_OPTION_LIMIT);
1865     int opt  = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
1866 
1867     initialize_wk_klass((WKID)id, opt, CHECK);
1868   }
1869 
1870   // move the starting value forward to the limit:
1871   start_id = limit_id;
1872 }
1873 
1874 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
1875   assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
1876   // Preload commonly used klasses
1877   WKID scan = FIRST_WKID;
1878   // first do Object, then String, Class
1879   if (UseSharedSpaces) {
1880     initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
1881     // Initialize the constant pool for the Object_class
1882     InstanceKlass* ik = InstanceKlass::cast(Object_klass());
1883     ik->constants()->restore_unshareable_info(CHECK);
1884     initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1885   } else {
1886     initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1887   }
1888 
1889   // Calculate offsets for String and Class classes since they are loaded and
1890   // can be used after this point.
1891   java_lang_String::compute_offsets();
1892   java_lang_Class::compute_offsets();
1893 
1894   // Fixup mirrors for classes loaded before java.lang.Class.
1895   // These calls iterate over the objects currently in the perm gen
1896   // so calling them at this point is matters (not before when there
1897   // are fewer objects and not later after there are more objects
1898   // in the perm gen.
1899   Universe::initialize_basic_type_mirrors(CHECK);
1900   Universe::fixup_mirrors(CHECK);
1901 
1902   // do a bunch more:
1903   initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
1904 
1905   // Preload ref klasses and set reference types
1906   InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
1907   InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
1908 
1909   initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
1910   InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
1911   InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
1912   InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
1913   InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
1914 
1915   // JSR 292 classes
1916   WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
1917   WKID jsr292_group_end   = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
1918   initialize_wk_klasses_until(jsr292_group_start, scan, CHECK);
1919   initialize_wk_klasses_through(jsr292_group_end, scan, CHECK);
1920   initialize_wk_klasses_until(WKID_LIMIT, scan, CHECK);
1921 
1922   _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
1923   _box_klasses[T_CHAR]    = WK_KLASS(Character_klass);
1924   _box_klasses[T_FLOAT]   = WK_KLASS(Float_klass);
1925   _box_klasses[T_DOUBLE]  = WK_KLASS(Double_klass);
1926   _box_klasses[T_BYTE]    = WK_KLASS(Byte_klass);
1927   _box_klasses[T_SHORT]   = WK_KLASS(Short_klass);
1928   _box_klasses[T_INT]     = WK_KLASS(Integer_klass);
1929   _box_klasses[T_LONG]    = WK_KLASS(Long_klass);
1930   //_box_klasses[T_OBJECT]  = WK_KLASS(object_klass);
1931   //_box_klasses[T_ARRAY]   = WK_KLASS(object_klass);
1932 
1933   { // Compute whether we should use loadClass or loadClassInternal when loading classes.
1934     Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature());
1935     _has_loadClassInternal = (method != NULL);
1936   }
1937   { // Compute whether we should use checkPackageAccess or NOT
1938     Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
1939     _has_checkPackageAccess = (method != NULL);
1940   }
1941 }
1942 
1943 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
1944 // If so, returns the basic type it holds.  If not, returns T_OBJECT.
1945 BasicType SystemDictionary::box_klass_type(Klass* k) {
1946   assert(k != NULL, "");
1947   for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
1948     if (_box_klasses[i] == k)
1949       return (BasicType)i;
1950   }
1951   return T_OBJECT;
1952 }
1953 
1954 // Constraints on class loaders. The details of the algorithm can be
1955 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
1956 // Virtual Machine" by Sheng Liang and Gilad Bracha.  The basic idea is
1957 // that the system dictionary needs to maintain a set of contraints that
1958 // must be satisfied by all classes in the dictionary.
1959 // if defining is true, then LinkageError if already in systemDictionary
1960 // if initiating loader, then ok if InstanceKlass matches existing entry
1961 
1962 void SystemDictionary::check_constraints(int d_index, unsigned int d_hash,
1963                                          instanceKlassHandle k,
1964                                          Handle class_loader, bool defining,
1965                                          TRAPS) {
1966   const char *linkage_error = NULL;
1967   {
1968     Symbol*  name  = k->name();
1969     ClassLoaderData *loader_data = class_loader_data(class_loader);
1970 
1971     MutexLocker mu(SystemDictionary_lock, THREAD);
1972 
1973     Klass* check = find_class(d_index, d_hash, name, loader_data);
1974     if (check != (Klass*)NULL) {
1975       // if different InstanceKlass - duplicate class definition,
1976       // else - ok, class loaded by a different thread in parallel,
1977       // we should only have found it if it was done loading and ok to use
1978       // system dictionary only holds instance classes, placeholders
1979       // also holds array classes
1980 
1981       assert(check->oop_is_instance(), "noninstance in systemdictionary");
1982       if ((defining == true) || (k() != check)) {
1983         linkage_error = "loader (instance of  %s): attempted  duplicate class "
1984           "definition for name: \"%s\"";
1985       } else {
1986         return;
1987       }
1988     }
1989 
1990 #ifdef ASSERT
1991     Symbol* ph_check = find_placeholder(name, loader_data);
1992     assert(ph_check == NULL || ph_check == name, "invalid symbol");
1993 #endif
1994 
1995     if (linkage_error == NULL) {
1996       if (constraints()->check_or_update(k, class_loader, name) == false) {
1997         linkage_error = "loader constraint violation: loader (instance of %s)"
1998           " previously initiated loading for a different type with name \"%s\"";
1999       }
2000     }
2001   }
2002 
2003   // Throw error now if needed (cannot throw while holding
2004   // SystemDictionary_lock because of rank ordering)
2005 
2006   if (linkage_error) {
2007     ResourceMark rm(THREAD);
2008     const char* class_loader_name = loader_name(class_loader());
2009     char* type_name = k->name()->as_C_string();
2010     size_t buflen = strlen(linkage_error) + strlen(class_loader_name) +
2011       strlen(type_name);
2012     char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
2013     jio_snprintf(buf, buflen, linkage_error, class_loader_name, type_name);
2014     THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
2015   }
2016 }
2017 
2018 
2019 // Update system dictionary - done after check_constraint and add_to_hierachy
2020 // have been called.
2021 void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash,
2022                                          int p_index, unsigned int p_hash,
2023                                          instanceKlassHandle k,
2024                                          Handle class_loader,
2025                                          TRAPS) {
2026   // Compile_lock prevents systemDictionary updates during compilations
2027   assert_locked_or_safepoint(Compile_lock);
2028   Symbol*  name  = k->name();
2029   ClassLoaderData *loader_data = class_loader_data(class_loader);
2030 
2031   {
2032   MutexLocker mu1(SystemDictionary_lock, THREAD);
2033 
2034   // See whether biased locking is enabled and if so set it for this
2035   // klass.
2036   // Note that this must be done past the last potential blocking
2037   // point / safepoint. We enable biased locking lazily using a
2038   // VM_Operation to iterate the SystemDictionary and installing the
2039   // biasable mark word into each InstanceKlass's prototype header.
2040   // To avoid race conditions where we accidentally miss enabling the
2041   // optimization for one class in the process of being added to the
2042   // dictionary, we must not safepoint after the test of
2043   // BiasedLocking::enabled().
2044   if (UseBiasedLocking && BiasedLocking::enabled()) {
2045     // Set biased locking bit for all loaded classes; it will be
2046     // cleared if revocation occurs too often for this type
2047     // NOTE that we must only do this when the class is initally
2048     // defined, not each time it is referenced from a new class loader
2049     if (k->class_loader() == class_loader()) {
2050       k->set_prototype_header(markOopDesc::biased_locking_prototype());
2051     }
2052   }
2053 
2054   // Make a new system dictionary entry.
2055   Klass* sd_check = find_class(d_index, d_hash, name, loader_data);
2056   if (sd_check == NULL) {
2057     dictionary()->add_klass(name, loader_data, k);
2058     notice_modification();
2059   }
2060 #ifdef ASSERT
2061   sd_check = find_class(d_index, d_hash, name, loader_data);
2062   assert (sd_check != NULL, "should have entry in system dictionary");
2063   // Note: there may be a placeholder entry: for circularity testing
2064   // or for parallel defines
2065 #endif
2066     SystemDictionary_lock->notify_all();
2067   }
2068 }
2069 
2070 
2071 // Try to find a class name using the loader constraints.  The
2072 // loader constraints might know about a class that isn't fully loaded
2073 // yet and these will be ignored.
2074 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2075                     Symbol* class_name, Handle class_loader, TRAPS) {
2076 
2077   // First see if it has been loaded directly.
2078   // Force the protection domain to be null.  (This removes protection checks.)
2079   Handle no_protection_domain;
2080   Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2081                                               no_protection_domain, CHECK_NULL);
2082   if (klass != NULL)
2083     return klass;
2084 
2085   // Now look to see if it has been loaded elsewhere, and is subject to
2086   // a loader constraint that would require this loader to return the
2087   // klass that is already loaded.
2088   if (FieldType::is_array(class_name)) {
2089     // For array classes, their Klass*s are not kept in the
2090     // constraint table. The element Klass*s are.
2091     FieldArrayInfo fd;
2092     BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2093     if (t != T_OBJECT) {
2094       klass = Universe::typeArrayKlassObj(t);
2095     } else {
2096       MutexLocker mu(SystemDictionary_lock, THREAD);
2097       klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2098     }
2099     // If element class already loaded, allocate array klass
2100     if (klass != NULL) {
2101       klass = klass->array_klass_or_null(fd.dimension());
2102     }
2103   } else {
2104     MutexLocker mu(SystemDictionary_lock, THREAD);
2105     // Non-array classes are easy: simply check the constraint table.
2106     klass = constraints()->find_constrained_klass(class_name, class_loader);
2107   }
2108 
2109   return klass;
2110 }
2111 
2112 
2113 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2114                                              Handle class_loader1,
2115                                              Handle class_loader2,
2116                                              Thread* THREAD) {
2117   ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2118   ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2119 
2120   Symbol* constraint_name = NULL;
2121   if (!FieldType::is_array(class_name)) {
2122     constraint_name = class_name;
2123   } else {
2124     // For array classes, their Klass*s are not kept in the
2125     // constraint table. The element classes are.
2126     FieldArrayInfo fd;
2127     BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2128     // primitive types always pass
2129     if (t != T_OBJECT) {
2130       return true;
2131     } else {
2132       constraint_name = fd.object_key();
2133     }
2134   }
2135   unsigned int d_hash1 = dictionary()->compute_hash(constraint_name, loader_data1);
2136   int d_index1 = dictionary()->hash_to_index(d_hash1);
2137 
2138   unsigned int d_hash2 = dictionary()->compute_hash(constraint_name, loader_data2);
2139   int d_index2 = dictionary()->hash_to_index(d_hash2);
2140   {
2141   MutexLocker mu_s(SystemDictionary_lock, THREAD);
2142 
2143   // Better never do a GC while we're holding these oops
2144   No_Safepoint_Verifier nosafepoint;
2145 
2146   Klass* klass1 = find_class(d_index1, d_hash1, constraint_name, loader_data1);
2147   Klass* klass2 = find_class(d_index2, d_hash2, constraint_name, loader_data2);
2148   return constraints()->add_entry(constraint_name, klass1, class_loader1,
2149                                   klass2, class_loader2);
2150   }
2151 }
2152 
2153 // Add entry to resolution error table to record the error when the first
2154 // attempt to resolve a reference to a class has failed.
2155 void SystemDictionary::add_resolution_error(constantPoolHandle pool, int which,
2156                                             Symbol* error, Symbol* message) {
2157   unsigned int hash = resolution_errors()->compute_hash(pool, which);
2158   int index = resolution_errors()->hash_to_index(hash);
2159   {
2160     MutexLocker ml(SystemDictionary_lock, Thread::current());
2161     resolution_errors()->add_entry(index, hash, pool, which, error, message);
2162   }
2163 }
2164 
2165 // Delete a resolution error for RedefineClasses for a constant pool is going away
2166 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2167   resolution_errors()->delete_entry(pool);
2168 }
2169 
2170 // Lookup resolution error table. Returns error if found, otherwise NULL.
2171 Symbol* SystemDictionary::find_resolution_error(constantPoolHandle pool, int which,
2172                                                 Symbol** message) {
2173   unsigned int hash = resolution_errors()->compute_hash(pool, which);
2174   int index = resolution_errors()->hash_to_index(hash);
2175   {
2176     MutexLocker ml(SystemDictionary_lock, Thread::current());
2177     ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2178     if (entry != NULL) {
2179       *message = entry->message();
2180       return entry->error();
2181     } else {
2182       return NULL;
2183     }
2184   }
2185 }
2186 
2187 
2188 // Signature constraints ensure that callers and callees agree about
2189 // the meaning of type names in their signatures.  This routine is the
2190 // intake for constraints.  It collects them from several places:
2191 //
2192 //  * LinkResolver::resolve_method (if check_access is true) requires
2193 //    that the resolving class (the caller) and the defining class of
2194 //    the resolved method (the callee) agree on each type in the
2195 //    method's signature.
2196 //
2197 //  * LinkResolver::resolve_interface_method performs exactly the same
2198 //    checks.
2199 //
2200 //  * LinkResolver::resolve_field requires that the constant pool
2201 //    attempting to link to a field agree with the field's defining
2202 //    class about the type of the field signature.
2203 //
2204 //  * klassVtable::initialize_vtable requires that, when a class
2205 //    overrides a vtable entry allocated by a superclass, that the
2206 //    overriding method (i.e., the callee) agree with the superclass
2207 //    on each type in the method's signature.
2208 //
2209 //  * klassItable::initialize_itable requires that, when a class fills
2210 //    in its itables, for each non-abstract method installed in an
2211 //    itable, the method (i.e., the callee) agree with the interface
2212 //    on each type in the method's signature.
2213 //
2214 // All those methods have a boolean (check_access, checkconstraints)
2215 // which turns off the checks.  This is used from specialized contexts
2216 // such as bootstrapping, dumping, and debugging.
2217 //
2218 // No direct constraint is placed between the class and its
2219 // supertypes.  Constraints are only placed along linked relations
2220 // between callers and callees.  When a method overrides or implements
2221 // an abstract method in a supertype (superclass or interface), the
2222 // constraints are placed as if the supertype were the caller to the
2223 // overriding method.  (This works well, since callers to the
2224 // supertype have already established agreement between themselves and
2225 // the supertype.)  As a result of all this, a class can disagree with
2226 // its supertype about the meaning of a type name, as long as that
2227 // class neither calls a relevant method of the supertype, nor is
2228 // called (perhaps via an override) from the supertype.
2229 //
2230 //
2231 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2232 //
2233 // Make sure all class components (including arrays) in the given
2234 // signature will be resolved to the same class in both loaders.
2235 // Returns the name of the type that failed a loader constraint check, or
2236 // NULL if no constraint failed.  No exception except OOME is thrown.
2237 // Arrays are not added to the loader constraint table, their elements are.
2238 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2239                                                Handle loader1, Handle loader2,
2240                                                bool is_method, TRAPS)  {
2241   // Nothing to do if loaders are the same.
2242   if (loader1() == loader2()) {
2243     return NULL;
2244   }
2245 
2246   SignatureStream sig_strm(signature, is_method);
2247   while (!sig_strm.is_done()) {
2248     if (sig_strm.is_object()) {
2249       Symbol* sig = sig_strm.as_symbol(CHECK_NULL);
2250       if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2251         return sig;
2252       }
2253     }
2254     sig_strm.next();
2255   }
2256   return NULL;
2257 }
2258 
2259 
2260 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2261                                                             Symbol* signature,
2262                                                             TRAPS) {
2263   methodHandle empty;
2264   assert(MethodHandles::is_signature_polymorphic(iid) &&
2265          MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2266          iid != vmIntrinsics::_invokeGeneric,
2267          err_msg("must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid)));
2268 
2269   unsigned int hash  = invoke_method_table()->compute_hash(signature, iid);
2270   int          index = invoke_method_table()->hash_to_index(hash);
2271   SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2272   methodHandle m;
2273   if (spe == NULL || spe->method() == NULL) {
2274     spe = NULL;
2275     // Must create lots of stuff here, but outside of the SystemDictionary lock.
2276     m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2277     CompileBroker::compile_method(m, InvocationEntryBci, CompLevel_highest_tier,
2278                                   methodHandle(), CompileThreshold, "MH", CHECK_(empty));
2279 
2280     // Now grab the lock.  We might have to throw away the new method,
2281     // if a racing thread has managed to install one at the same time.
2282     {
2283       MutexLocker ml(SystemDictionary_lock, THREAD);
2284       spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2285       if (spe == NULL)
2286         spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2287       if (spe->method() == NULL)
2288         spe->set_method(m());
2289     }
2290   }
2291 
2292   assert(spe != NULL && spe->method() != NULL, "");
2293   assert(!UseCompiler || (spe->method()->has_compiled_code() &&
2294          spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2295          "MH intrinsic invariant");
2296   return spe->method();
2297 }
2298 
2299 // Helper for unpacking the return value from linkMethod and linkCallSite.
2300 static methodHandle unpack_method_and_appendix(Handle mname,
2301                                                KlassHandle accessing_klass,
2302                                                objArrayHandle appendix_box,
2303                                                Handle* appendix_result,
2304                                                TRAPS) {
2305   methodHandle empty;
2306   if (mname.not_null()) {
2307     Metadata* vmtarget = java_lang_invoke_MemberName::vmtarget(mname());
2308     if (vmtarget != NULL && vmtarget->is_method()) {
2309       Method* m = (Method*)vmtarget;
2310       oop appendix = appendix_box->obj_at(0);
2311       if (TraceMethodHandles) {
2312     #ifndef PRODUCT
2313         tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2314         m->print();
2315         if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2316         tty->cr();
2317     #endif //PRODUCT
2318       }
2319       (*appendix_result) = Handle(THREAD, appendix);
2320       // the target is stored in the cpCache and if a reference to this
2321       // MethodName is dropped we need a way to make sure the
2322       // class_loader containing this method is kept alive.
2323       // FIXME: the appendix might also preserve this dependency.
2324       ClassLoaderData* this_key = InstanceKlass::cast(accessing_klass())->class_loader_data();
2325       this_key->record_dependency(m->method_holder(), CHECK_NULL); // Can throw OOM
2326       return methodHandle(THREAD, m);
2327     }
2328   }
2329   THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2330   return empty;
2331 }
2332 
2333 methodHandle SystemDictionary::find_method_handle_invoker(Symbol* name,
2334                                                           Symbol* signature,
2335                                                           KlassHandle accessing_klass,
2336                                                           Handle *appendix_result,
2337                                                           Handle *method_type_result,
2338                                                           TRAPS) {
2339   methodHandle empty;
2340   assert(!THREAD->is_Compiler_thread(), "");
2341   Handle method_type =
2342     SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2343   if (false) {  // FIXME: Decide if the Java upcall should resolve signatures.
2344     method_type = java_lang_String::create_from_symbol(signature, CHECK_(empty));
2345   }
2346 
2347   KlassHandle  mh_klass = SystemDictionary::MethodHandle_klass();
2348   int ref_kind = JVM_REF_invokeVirtual;
2349   Handle name_str = StringTable::intern(name, CHECK_(empty));
2350   objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2351   assert(appendix_box->obj_at(0) == NULL, "");
2352 
2353   // This should not happen.  JDK code should take care of that.
2354   if (accessing_klass.is_null() || method_type.is_null()) {
2355     THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
2356   }
2357 
2358   // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2359   JavaCallArguments args;
2360   args.push_oop(accessing_klass()->java_mirror());
2361   args.push_int(ref_kind);
2362   args.push_oop(mh_klass()->java_mirror());
2363   args.push_oop(name_str());
2364   args.push_oop(method_type());
2365   args.push_oop(appendix_box());
2366   JavaValue result(T_OBJECT);
2367   JavaCalls::call_static(&result,
2368                          SystemDictionary::MethodHandleNatives_klass(),
2369                          vmSymbols::linkMethod_name(),
2370                          vmSymbols::linkMethod_signature(),
2371                          &args, CHECK_(empty));
2372   Handle mname(THREAD, (oop) result.get_jobject());
2373   (*method_type_result) = method_type;
2374   return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2375 }
2376 
2377 
2378 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2379 // signature, as interpreted relative to the given class loader.
2380 // Because of class loader constraints, all method handle usage must be
2381 // consistent with this loader.
2382 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2383                                                  KlassHandle accessing_klass,
2384                                                  TRAPS) {
2385   Handle empty;
2386   vmIntrinsics::ID null_iid = vmIntrinsics::_none;  // distinct from all method handle invoker intrinsics
2387   unsigned int hash  = invoke_method_table()->compute_hash(signature, null_iid);
2388   int          index = invoke_method_table()->hash_to_index(hash);
2389   SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2390   if (spe != NULL && spe->method_type() != NULL) {
2391     assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2392     return Handle(THREAD, spe->method_type());
2393   } else if (THREAD->is_Compiler_thread()) {
2394     warning("SystemDictionary::find_method_handle_type called from compiler thread");  // FIXME
2395     return Handle();  // do not attempt from within compiler, unless it was cached
2396   }
2397 
2398   Handle class_loader, protection_domain;
2399   bool is_on_bcp = true;  // keep this true as long as we can materialize from the boot classloader
2400   int npts = ArgumentCount(signature).size();
2401   objArrayHandle pts = oopFactory::new_objArray(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2402   int arg = 0;
2403   Handle rt;                            // the return type from the signature
2404   ResourceMark rm(THREAD);
2405   for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2406     oop mirror = NULL;
2407     if (is_on_bcp) {
2408       // Note:  class_loader & protection_domain are both null at this point.
2409       mirror = ss.as_java_mirror(class_loader, protection_domain,
2410                                  SignatureStream::ReturnNull, CHECK_(empty));
2411       if (mirror == NULL) {
2412         // fall back from BCP to accessing_klass
2413         if (accessing_klass.not_null()) {
2414           class_loader      = Handle(THREAD, InstanceKlass::cast(accessing_klass())->class_loader());
2415           protection_domain = Handle(THREAD, InstanceKlass::cast(accessing_klass())->protection_domain());
2416         }
2417         is_on_bcp = false;
2418       }
2419     }
2420     if (!is_on_bcp) {
2421       // Resolve, throwing a real error if it doesn't work.
2422       mirror = ss.as_java_mirror(class_loader, protection_domain,
2423                                  SignatureStream::NCDFError, CHECK_(empty));
2424     }
2425     if (ss.at_return_type())
2426       rt = Handle(THREAD, mirror);
2427     else
2428       pts->obj_at_put(arg++, mirror);
2429 
2430     // Check accessibility.
2431     if (ss.is_object() && accessing_klass.not_null()) {
2432       Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2433       mirror = NULL;  // safety
2434       // Emulate ConstantPool::verify_constant_pool_resolve.
2435       if (sel_klass->oop_is_objArray())
2436         sel_klass = ObjArrayKlass::cast(sel_klass)->bottom_klass();
2437       if (sel_klass->oop_is_instance()) {
2438         KlassHandle sel_kh(THREAD, sel_klass);
2439         LinkResolver::check_klass_accessability(accessing_klass, sel_kh, CHECK_(empty));
2440       }
2441     }
2442   }
2443   assert(arg == npts, "");
2444 
2445   // call java.lang.invoke.MethodHandleNatives::findMethodType(Class rt, Class[] pts) -> MethodType
2446   JavaCallArguments args(Handle(THREAD, rt()));
2447   args.push_oop(pts());
2448   JavaValue result(T_OBJECT);
2449   JavaCalls::call_static(&result,
2450                          SystemDictionary::MethodHandleNatives_klass(),
2451                          vmSymbols::findMethodHandleType_name(),
2452                          vmSymbols::findMethodHandleType_signature(),
2453                          &args, CHECK_(empty));
2454   Handle method_type(THREAD, (oop) result.get_jobject());
2455 
2456   if (is_on_bcp) {
2457     // We can cache this MethodType inside the JVM.
2458     MutexLocker ml(SystemDictionary_lock, THREAD);
2459     spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2460     if (spe == NULL)
2461       spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2462     if (spe->method_type() == NULL) {
2463       spe->set_method_type(method_type());
2464     }
2465   }
2466 
2467   // report back to the caller with the MethodType
2468   return method_type;
2469 }
2470 
2471 // Ask Java code to find or construct a method handle constant.
2472 Handle SystemDictionary::link_method_handle_constant(KlassHandle caller,
2473                                                      int ref_kind, //e.g., JVM_REF_invokeVirtual
2474                                                      KlassHandle callee,
2475                                                      Symbol* name_sym,
2476                                                      Symbol* signature,
2477                                                      TRAPS) {
2478   Handle empty;
2479   Handle name = java_lang_String::create_from_symbol(name_sym, CHECK_(empty));
2480   Handle type;
2481   if (signature->utf8_length() > 0 && signature->byte_at(0) == '(') {
2482     type = find_method_handle_type(signature, caller, CHECK_(empty));
2483   } else if (caller.is_null()) {
2484     // This should not happen.  JDK code should take care of that.
2485     THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2486   } else {
2487     ResourceMark rm(THREAD);
2488     SignatureStream ss(signature, false);
2489     if (!ss.is_done()) {
2490       oop mirror = ss.as_java_mirror(caller->class_loader(), caller->protection_domain(),
2491                                      SignatureStream::NCDFError, CHECK_(empty));
2492       type = Handle(THREAD, mirror);
2493       ss.next();
2494       if (!ss.is_done())  type = Handle();  // error!
2495     }
2496   }
2497   if (type.is_null()) {
2498     THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad signature", empty);
2499   }
2500 
2501   // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2502   JavaCallArguments args;
2503   args.push_oop(caller->java_mirror());  // the referring class
2504   args.push_int(ref_kind);
2505   args.push_oop(callee->java_mirror());  // the target class
2506   args.push_oop(name());
2507   args.push_oop(type());
2508   JavaValue result(T_OBJECT);
2509   JavaCalls::call_static(&result,
2510                          SystemDictionary::MethodHandleNatives_klass(),
2511                          vmSymbols::linkMethodHandleConstant_name(),
2512                          vmSymbols::linkMethodHandleConstant_signature(),
2513                          &args, CHECK_(empty));
2514   return Handle(THREAD, (oop) result.get_jobject());
2515 }
2516 
2517 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2518 // name and signature, as interpreted relative to the given class loader.
2519 methodHandle SystemDictionary::find_dynamic_call_site_invoker(KlassHandle caller,
2520                                                               Handle bootstrap_specifier,
2521                                                               Symbol* name,
2522                                                               Symbol* type,
2523                                                               Handle *appendix_result,
2524                                                               Handle *method_type_result,
2525                                                               TRAPS) {
2526   methodHandle empty;
2527   Handle bsm, info;
2528   if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2529     bsm = bootstrap_specifier;
2530   } else {
2531     assert(bootstrap_specifier->is_objArray(), "");
2532     objArrayHandle args(THREAD, (objArrayOop) bootstrap_specifier());
2533     int len = args->length();
2534     assert(len >= 1, "");
2535     bsm = Handle(THREAD, args->obj_at(0));
2536     if (len > 1) {
2537       objArrayOop args1 = oopFactory::new_objArray(SystemDictionary::Object_klass(), len-1, CHECK_(empty));
2538       for (int i = 1; i < len; i++)
2539         args1->obj_at_put(i-1, args->obj_at(i));
2540       info = Handle(THREAD, args1);
2541     }
2542   }
2543   guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2544             "caller must supply a valid BSM");
2545 
2546   Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2547   Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2548 
2549   // This should not happen.  JDK code should take care of that.
2550   if (caller.is_null() || method_type.is_null()) {
2551     THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty);
2552   }
2553 
2554   objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2555   assert(appendix_box->obj_at(0) == NULL, "");
2556 
2557   // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, bsm, name, mtype, info, &appendix)
2558   JavaCallArguments args;
2559   args.push_oop(caller->java_mirror());
2560   args.push_oop(bsm());
2561   args.push_oop(method_name());
2562   args.push_oop(method_type());
2563   args.push_oop(info());
2564   args.push_oop(appendix_box);
2565   JavaValue result(T_OBJECT);
2566   JavaCalls::call_static(&result,
2567                          SystemDictionary::MethodHandleNatives_klass(),
2568                          vmSymbols::linkCallSite_name(),
2569                          vmSymbols::linkCallSite_signature(),
2570                          &args, CHECK_(empty));
2571   Handle mname(THREAD, (oop) result.get_jobject());
2572   (*method_type_result) = method_type;
2573   return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
2574 }
2575 
2576 // Since the identity hash code for symbols changes when the symbols are
2577 // moved from the regular perm gen (hash in the mark word) to the shared
2578 // spaces (hash is the address), the classes loaded into the dictionary
2579 // may be in the wrong buckets.
2580 
2581 void SystemDictionary::reorder_dictionary() {
2582   dictionary()->reorder_dictionary();
2583 }
2584 
2585 
2586 void SystemDictionary::copy_buckets(char** top, char* end) {
2587   dictionary()->copy_buckets(top, end);
2588 }
2589 
2590 
2591 void SystemDictionary::copy_table(char** top, char* end) {
2592   dictionary()->copy_table(top, end);
2593 }
2594 
2595 
2596 void SystemDictionary::reverse() {
2597   dictionary()->reverse();
2598 }
2599 
2600 int SystemDictionary::number_of_classes() {
2601   return dictionary()->number_of_entries();
2602 }
2603 
2604 
2605 // ----------------------------------------------------------------------------
2606 void SystemDictionary::print_shared(bool details) {
2607   shared_dictionary()->print(details);
2608 }
2609 
2610 void SystemDictionary::print(bool details) {
2611   dictionary()->print(details);
2612 
2613   // Placeholders
2614   GCMutexLocker mu(SystemDictionary_lock);
2615   placeholders()->print();
2616 
2617   // loader constraints - print under SD_lock
2618   constraints()->print();
2619 }
2620 
2621 
2622 void SystemDictionary::verify() {
2623   guarantee(dictionary() != NULL, "Verify of system dictionary failed");
2624   guarantee(constraints() != NULL,
2625             "Verify of loader constraints failed");
2626   guarantee(dictionary()->number_of_entries() >= 0 &&
2627             placeholders()->number_of_entries() >= 0,
2628             "Verify of system dictionary failed");
2629 
2630   // Verify dictionary
2631   dictionary()->verify();
2632 
2633   GCMutexLocker mu(SystemDictionary_lock);
2634   placeholders()->verify();
2635 
2636   // Verify constraint table
2637   guarantee(constraints() != NULL, "Verify of loader constraints failed");
2638   constraints()->verify(dictionary(), placeholders());
2639 }
2640 
2641 // utility function for class load event
2642 void SystemDictionary::post_class_load_event(const Ticks& start_time,
2643                                              instanceKlassHandle k,
2644                                              Handle initiating_loader) {
2645 #if INCLUDE_TRACE
2646   EventClassLoad event(UNTIMED);
2647   if (event.should_commit()) {
2648     event.set_starttime(start_time);
2649     event.set_loadedClass(k());
2650     oop defining_class_loader = k->class_loader();
2651     event.set_definingClassLoader(defining_class_loader !=  NULL ?
2652                                     defining_class_loader->klass() : (Klass*)NULL);
2653     oop class_loader = initiating_loader.is_null() ? (oop)NULL : initiating_loader();
2654     event.set_initiatingClassLoader(class_loader != NULL ?
2655                                       class_loader->klass() : (Klass*)NULL);
2656     event.commit();
2657   }
2658 #endif /* INCLUDE_TRACE */
2659 }
2660 
2661 #ifndef PRODUCT
2662 
2663 // statistics code
2664 class ClassStatistics: AllStatic {
2665  private:
2666   static int nclasses;        // number of classes
2667   static int nmethods;        // number of methods
2668   static int nmethoddata;     // number of methodData
2669   static int class_size;      // size of class objects in words
2670   static int method_size;     // size of method objects in words
2671   static int debug_size;      // size of debug info in methods
2672   static int methoddata_size; // size of methodData objects in words
2673 
2674   static void do_class(Klass* k) {
2675     nclasses++;
2676     class_size += k->size();
2677     if (k->oop_is_instance()) {
2678       InstanceKlass* ik = (InstanceKlass*)k;
2679       class_size += ik->methods()->size();
2680       class_size += ik->constants()->size();
2681       class_size += ik->local_interfaces()->size();
2682       class_size += ik->transitive_interfaces()->size();
2683       // We do not have to count implementors, since we only store one!
2684       // SSS: How should these be accounted now that they have moved?
2685       // class_size += ik->fields()->length();
2686     }
2687   }
2688 
2689   static void do_method(Method* m) {
2690     nmethods++;
2691     method_size += m->size();
2692     // class loader uses same objArray for empty vectors, so don't count these
2693     if (m->has_stackmap_table()) {
2694       method_size += m->stackmap_data()->size();
2695     }
2696 
2697     MethodData* mdo = m->method_data();
2698     if (mdo != NULL) {
2699       nmethoddata++;
2700       methoddata_size += mdo->size();
2701     }
2702   }
2703 
2704  public:
2705   static void print() {
2706     SystemDictionary::classes_do(do_class);
2707     SystemDictionary::methods_do(do_method);
2708     tty->print_cr("Class statistics:");
2709     tty->print_cr("%d classes (%d bytes)", nclasses, class_size * oopSize);
2710     tty->print_cr("%d methods (%d bytes = %d base + %d debug info)", nmethods,
2711                   (method_size + debug_size) * oopSize, method_size * oopSize, debug_size * oopSize);
2712     tty->print_cr("%d methoddata (%d bytes)", nmethoddata, methoddata_size * oopSize);
2713   }
2714 };
2715 
2716 
2717 int ClassStatistics::nclasses        = 0;
2718 int ClassStatistics::nmethods        = 0;
2719 int ClassStatistics::nmethoddata     = 0;
2720 int ClassStatistics::class_size      = 0;
2721 int ClassStatistics::method_size     = 0;
2722 int ClassStatistics::debug_size      = 0;
2723 int ClassStatistics::methoddata_size = 0;
2724 
2725 void SystemDictionary::print_class_statistics() {
2726   ResourceMark rm;
2727   ClassStatistics::print();
2728 }
2729 
2730 
2731 class MethodStatistics: AllStatic {
2732  public:
2733   enum {
2734     max_parameter_size = 10
2735   };
2736  private:
2737 
2738   static int _number_of_methods;
2739   static int _number_of_final_methods;
2740   static int _number_of_static_methods;
2741   static int _number_of_native_methods;
2742   static int _number_of_synchronized_methods;
2743   static int _number_of_profiled_methods;
2744   static int _number_of_bytecodes;
2745   static int _parameter_size_profile[max_parameter_size];
2746   static int _bytecodes_profile[Bytecodes::number_of_java_codes];
2747 
2748   static void initialize() {
2749     _number_of_methods        = 0;
2750     _number_of_final_methods  = 0;
2751     _number_of_static_methods = 0;
2752     _number_of_native_methods = 0;
2753     _number_of_synchronized_methods = 0;
2754     _number_of_profiled_methods = 0;
2755     _number_of_bytecodes      = 0;
2756     for (int i = 0; i < max_parameter_size             ; i++) _parameter_size_profile[i] = 0;
2757     for (int j = 0; j < Bytecodes::number_of_java_codes; j++) _bytecodes_profile     [j] = 0;
2758   };
2759 
2760   static void do_method(Method* m) {
2761     _number_of_methods++;
2762     // collect flag info
2763     if (m->is_final()       ) _number_of_final_methods++;
2764     if (m->is_static()      ) _number_of_static_methods++;
2765     if (m->is_native()      ) _number_of_native_methods++;
2766     if (m->is_synchronized()) _number_of_synchronized_methods++;
2767     if (m->method_data() != NULL) _number_of_profiled_methods++;
2768     // collect parameter size info (add one for receiver, if any)
2769     _parameter_size_profile[MIN2(m->size_of_parameters() + (m->is_static() ? 0 : 1), max_parameter_size - 1)]++;
2770     // collect bytecodes info
2771     {
2772       Thread *thread = Thread::current();
2773       HandleMark hm(thread);
2774       BytecodeStream s(methodHandle(thread, m));
2775       Bytecodes::Code c;
2776       while ((c = s.next()) >= 0) {
2777         _number_of_bytecodes++;
2778         _bytecodes_profile[c]++;
2779       }
2780     }
2781   }
2782 
2783  public:
2784   static void print() {
2785     initialize();
2786     SystemDictionary::methods_do(do_method);
2787     // generate output
2788     tty->cr();
2789     tty->print_cr("Method statistics (static):");
2790     // flag distribution
2791     tty->cr();
2792     tty->print_cr("%6d final        methods  %6.1f%%", _number_of_final_methods       , _number_of_final_methods        * 100.0F / _number_of_methods);
2793     tty->print_cr("%6d static       methods  %6.1f%%", _number_of_static_methods      , _number_of_static_methods       * 100.0F / _number_of_methods);
2794     tty->print_cr("%6d native       methods  %6.1f%%", _number_of_native_methods      , _number_of_native_methods       * 100.0F / _number_of_methods);
2795     tty->print_cr("%6d synchronized methods  %6.1f%%", _number_of_synchronized_methods, _number_of_synchronized_methods * 100.0F / _number_of_methods);
2796     tty->print_cr("%6d profiled     methods  %6.1f%%", _number_of_profiled_methods, _number_of_profiled_methods * 100.0F / _number_of_methods);
2797     // parameter size profile
2798     tty->cr();
2799     { int tot = 0;
2800       int avg = 0;
2801       for (int i = 0; i < max_parameter_size; i++) {
2802         int n = _parameter_size_profile[i];
2803         tot += n;
2804         avg += n*i;
2805         tty->print_cr("parameter size = %1d: %6d methods  %5.1f%%", i, n, n * 100.0F / _number_of_methods);
2806       }
2807       assert(tot == _number_of_methods, "should be the same");
2808       tty->print_cr("                    %6d methods  100.0%%", _number_of_methods);
2809       tty->print_cr("(average parameter size = %3.1f including receiver, if any)", (float)avg / _number_of_methods);
2810     }
2811     // bytecodes profile
2812     tty->cr();
2813     { int tot = 0;
2814       for (int i = 0; i < Bytecodes::number_of_java_codes; i++) {
2815         if (Bytecodes::is_defined(i)) {
2816           Bytecodes::Code c = Bytecodes::cast(i);
2817           int n = _bytecodes_profile[c];
2818           tot += n;
2819           tty->print_cr("%9d  %7.3f%%  %s", n, n * 100.0F / _number_of_bytecodes, Bytecodes::name(c));
2820         }
2821       }
2822       assert(tot == _number_of_bytecodes, "should be the same");
2823       tty->print_cr("%9d  100.000%%", _number_of_bytecodes);
2824     }
2825     tty->cr();
2826   }
2827 };
2828 
2829 int MethodStatistics::_number_of_methods;
2830 int MethodStatistics::_number_of_final_methods;
2831 int MethodStatistics::_number_of_static_methods;
2832 int MethodStatistics::_number_of_native_methods;
2833 int MethodStatistics::_number_of_synchronized_methods;
2834 int MethodStatistics::_number_of_profiled_methods;
2835 int MethodStatistics::_number_of_bytecodes;
2836 int MethodStatistics::_parameter_size_profile[MethodStatistics::max_parameter_size];
2837 int MethodStatistics::_bytecodes_profile[Bytecodes::number_of_java_codes];
2838 
2839 
2840 void SystemDictionary::print_method_statistics() {
2841   MethodStatistics::print();
2842 }
2843 
2844 #endif // PRODUCT
--- EOF ---