rev 1081 : imported patch indy-cleanup-6893081.patch

   1 /*
   2  * Copyright 1997-2009 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  20  * CA 95054 USA or visit www.sun.com if you need additional information or
  21  * have any questions.
  22  *
  23  */
  24 
  25 # include "incls/_precompiled.incl"
  26 # include "incls/_systemDictionary.cpp.incl"
  27 
  28 
  29 Dictionary*       SystemDictionary::_dictionary = NULL;
  30 PlaceholderTable* SystemDictionary::_placeholders = NULL;
  31 Dictionary*       SystemDictionary::_shared_dictionary = NULL;
  32 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
  33 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
  34 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
  35 
  36 
  37 int         SystemDictionary::_number_of_modifications = 0;
  38 
  39 oop         SystemDictionary::_system_loader_lock_obj     =  NULL;
  40 
  41 klassOop    SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
  42                                                           =  { NULL /*, NULL...*/ };
  43 
  44 klassOop    SystemDictionary::_box_klasses[T_VOID+1]      =  { NULL /*, NULL...*/ };
  45 
  46 oop         SystemDictionary::_java_system_loader         =  NULL;
  47 
  48 bool        SystemDictionary::_has_loadClassInternal      =  false;
  49 bool        SystemDictionary::_has_checkPackageAccess     =  false;
  50 
  51 // lazily initialized klass variables
  52 volatile klassOop    SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
  53 
  54 
  55 // ----------------------------------------------------------------------------
  56 // Java-level SystemLoader
  57 
  58 oop SystemDictionary::java_system_loader() {
  59   return _java_system_loader;
  60 }
  61 
  62 void SystemDictionary::compute_java_system_loader(TRAPS) {
  63   KlassHandle system_klass(THREAD, WK_KLASS(classloader_klass));
  64   JavaValue result(T_OBJECT);
  65   JavaCalls::call_static(&result,
  66                          KlassHandle(THREAD, WK_KLASS(classloader_klass)),
  67                          vmSymbolHandles::getSystemClassLoader_name(),
  68                          vmSymbolHandles::void_classloader_signature(),
  69                          CHECK);
  70 
  71   _java_system_loader = (oop)result.get_jobject();
  72 }
  73 
  74 
  75 // ----------------------------------------------------------------------------
  76 // debugging
  77 
  78 #ifdef ASSERT
  79 
  80 // return true if class_name contains no '.' (internal format is '/')
  81 bool SystemDictionary::is_internal_format(symbolHandle class_name) {
  82   if (class_name.not_null()) {
  83     ResourceMark rm;
  84     char* name = class_name->as_C_string();
  85     return strchr(name, '.') == NULL;
  86   } else {
  87     return true;
  88   }
  89 }
  90 
  91 #endif
  92 
  93 // ----------------------------------------------------------------------------
  94 // Parallel class loading check
  95 
  96 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
  97   if (UnsyncloadClass || class_loader.is_null()) return true;
  98   if (AlwaysLockClassLoader) return false;
  99   return java_lang_Class::parallelCapable(class_loader());
 100 }
 101 // ----------------------------------------------------------------------------
 102 // ParallelDefineClass flag does not apply to bootclass loader
 103 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
 104    if (class_loader.is_null()) return false;
 105    if (AllowParallelDefineClass && java_lang_Class::parallelCapable(class_loader())) {
 106      return true;
 107    }
 108    return false;
 109 }
 110 // ----------------------------------------------------------------------------
 111 // Resolving of classes
 112 
 113 // Forwards to resolve_or_null
 114 
 115 klassOop SystemDictionary::resolve_or_fail(symbolHandle class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
 116   klassOop klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
 117   if (HAS_PENDING_EXCEPTION || klass == NULL) {
 118     KlassHandle k_h(THREAD, klass);
 119     // can return a null klass
 120     klass = handle_resolution_exception(class_name, class_loader, protection_domain, throw_error, k_h, THREAD);
 121   }
 122   return klass;
 123 }
 124 
 125 klassOop SystemDictionary::handle_resolution_exception(symbolHandle class_name, Handle class_loader, Handle protection_domain, bool throw_error, KlassHandle klass_h, TRAPS) {
 126   if (HAS_PENDING_EXCEPTION) {
 127     // If we have a pending exception we forward it to the caller, unless throw_error is true,
 128     // in which case we have to check whether the pending exception is a ClassNotFoundException,
 129     // and if so convert it to a NoClassDefFoundError
 130     // And chain the original ClassNotFoundException
 131     if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::classNotFoundException_klass())) {
 132       ResourceMark rm(THREAD);
 133       assert(klass_h() == NULL, "Should not have result with exception pending");
 134       Handle e(THREAD, PENDING_EXCEPTION);
 135       CLEAR_PENDING_EXCEPTION;
 136       THROW_MSG_CAUSE_0(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
 137     } else {
 138       return NULL;
 139     }
 140   }
 141   // Class not found, throw appropriate error or exception depending on value of throw_error
 142   if (klass_h() == NULL) {
 143     ResourceMark rm(THREAD);
 144     if (throw_error) {
 145       THROW_MSG_0(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
 146     } else {
 147       THROW_MSG_0(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
 148     }
 149   }
 150   return (klassOop)klass_h();
 151 }
 152 
 153 
 154 klassOop SystemDictionary::resolve_or_fail(symbolHandle class_name,
 155                                            bool throw_error, TRAPS)
 156 {
 157   return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
 158 }
 159 
 160 
 161 // Forwards to resolve_instance_class_or_null
 162 
 163 klassOop SystemDictionary::resolve_or_null(symbolHandle class_name, Handle class_loader, Handle protection_domain, TRAPS) {
 164   assert(!THREAD->is_Compiler_thread(), "Can not load classes with the Compiler thread");
 165   if (FieldType::is_array(class_name())) {
 166     return resolve_array_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
 167   } else {
 168     return resolve_instance_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
 169   }
 170 }
 171 
 172 klassOop SystemDictionary::resolve_or_null(symbolHandle class_name, TRAPS) {
 173   return resolve_or_null(class_name, Handle(), Handle(), THREAD);
 174 }
 175 
 176 // Forwards to resolve_instance_class_or_null
 177 
 178 klassOop SystemDictionary::resolve_array_class_or_null(symbolHandle class_name,
 179                                                        Handle class_loader,
 180                                                        Handle protection_domain,
 181                                                        TRAPS) {
 182   assert(FieldType::is_array(class_name()), "must be array");
 183   jint dimension;
 184   symbolOop object_key;
 185   klassOop k = NULL;
 186   // dimension and object_key are assigned as a side-effect of this call
 187   BasicType t = FieldType::get_array_info(class_name(),
 188                                           &dimension,
 189                                           &object_key,
 190                                           CHECK_NULL);
 191 
 192   if (t == T_OBJECT) {
 193     symbolHandle h_key(THREAD, object_key);
 194     // naked oop "k" is OK here -- we assign back into it
 195     k = SystemDictionary::resolve_instance_class_or_null(h_key,
 196                                                          class_loader,
 197                                                          protection_domain,
 198                                                          CHECK_NULL);
 199     if (k != NULL) {
 200       k = Klass::cast(k)->array_klass(dimension, CHECK_NULL);
 201     }
 202   } else {
 203     k = Universe::typeArrayKlassObj(t);
 204     k = typeArrayKlass::cast(k)->array_klass(dimension, CHECK_NULL);
 205   }
 206   return k;
 207 }
 208 
 209 
 210 // Must be called for any super-class or super-interface resolution
 211 // during class definition to allow class circularity checking
 212 // super-interface callers:
 213 //    parse_interfaces - for defineClass & jvmtiRedefineClasses
 214 // super-class callers:
 215 //   ClassFileParser - for defineClass & jvmtiRedefineClasses
 216 //   load_shared_class - while loading a class from shared archive
 217 //   resolve_instance_class_or_null:
 218 //     via: handle_parallel_super_load
 219 //      when resolving a class that has an existing placeholder with
 220 //      a saved superclass [i.e. a defineClass is currently in progress]
 221 //      if another thread is trying to resolve the class, it must do
 222 //      super-class checks on its own thread to catch class circularity
 223 // This last call is critical in class circularity checking for cases
 224 // where classloading is delegated to different threads and the
 225 // classloader lock is released.
 226 // Take the case: Base->Super->Base
 227 //   1. If thread T1 tries to do a defineClass of class Base
 228 //    resolve_super_or_fail creates placeholder: T1, Base (super Super)
 229 //   2. resolve_instance_class_or_null does not find SD or placeholder for Super
 230 //    so it tries to load Super
 231 //   3. If we load the class internally, or user classloader uses same thread
 232 //      loadClassFromxxx or defineClass via parseClassFile Super ...
 233 //      3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
 234 //      3.3 resolve_instance_class_or_null Base, finds placeholder for Base
 235 //      3.4 calls resolve_super_or_fail Base
 236 //      3.5 finds T1,Base -> throws class circularity
 237 //OR 4. If T2 tries to resolve Super via defineClass Super ...
 238 //      4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
 239 //      4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
 240 //      4.3 calls resolve_super_or_fail Super in parallel on own thread T2
 241 //      4.4 finds T2, Super -> throws class circularity
 242 // Must be called, even if superclass is null, since this is
 243 // where the placeholder entry is created which claims this
 244 // thread is loading this class/classloader.
 245 klassOop SystemDictionary::resolve_super_or_fail(symbolHandle child_name,
 246                                                  symbolHandle class_name,
 247                                                  Handle class_loader,
 248                                                  Handle protection_domain,
 249                                                  bool is_superclass,
 250                                                  TRAPS) {
 251 
 252   // Try to get one of the well-known klasses.
 253   // They are trusted, and do not participate in circularities.
 254   if (LinkWellKnownClasses) {
 255     klassOop k = find_well_known_klass(class_name());
 256     if (k != NULL) {
 257       return k;
 258     }
 259   }
 260 
 261   // Double-check, if child class is already loaded, just return super-class,interface
 262   // Don't add a placedholder if already loaded, i.e. already in system dictionary
 263   // Make sure there's a placeholder for the *child* before resolving.
 264   // Used as a claim that this thread is currently loading superclass/classloader
 265   // Used here for ClassCircularity checks and also for heap verification
 266   // (every instanceKlass in the heap needs to be in the system dictionary
 267   // or have a placeholder).
 268   // Must check ClassCircularity before checking if super class is already loaded
 269   //
 270   // We might not already have a placeholder if this child_name was
 271   // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
 272   // the name of the class might not be known until the stream is actually
 273   // parsed.
 274   // Bugs 4643874, 4715493
 275   // compute_hash can have a safepoint
 276 
 277   unsigned int d_hash = dictionary()->compute_hash(child_name, class_loader);
 278   int d_index = dictionary()->hash_to_index(d_hash);
 279   unsigned int p_hash = placeholders()->compute_hash(child_name, class_loader);
 280   int p_index = placeholders()->hash_to_index(p_hash);
 281   // can't throw error holding a lock
 282   bool child_already_loaded = false;
 283   bool throw_circularity_error = false;
 284   {
 285     MutexLocker mu(SystemDictionary_lock, THREAD);
 286     klassOop childk = find_class(d_index, d_hash, child_name, class_loader);
 287     klassOop quicksuperk;
 288     // to support // loading: if child done loading, just return superclass
 289     // if class_name, & class_loader don't match:
 290     // if initial define, SD update will give LinkageError
 291     // if redefine: compare_class_versions will give HIERARCHY_CHANGED
 292     // so we don't throw an exception here.
 293     // see: nsk redefclass014 & java.lang.instrument Instrument032
 294     if ((childk != NULL ) && (is_superclass) &&
 295        ((quicksuperk = instanceKlass::cast(childk)->super()) != NULL) &&
 296 
 297          ((Klass::cast(quicksuperk)->name() == class_name()) &&
 298             (Klass::cast(quicksuperk)->class_loader()  == class_loader()))) {
 299            return quicksuperk;
 300     } else {
 301       PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, class_loader);
 302       if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
 303           throw_circularity_error = true;
 304       }
 305     }
 306     if (!throw_circularity_error) {
 307       PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, class_loader, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
 308     }
 309   }
 310   if (throw_circularity_error) {
 311       ResourceMark rm(THREAD);
 312       THROW_MSG_0(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
 313   }
 314 
 315 // java.lang.Object should have been found above
 316   assert(class_name() != NULL, "null super class for resolving");
 317   // Resolve the super class or interface, check results on return
 318   klassOop superk = NULL;
 319   superk = SystemDictionary::resolve_or_null(class_name,
 320                                                  class_loader,
 321                                                  protection_domain,
 322                                                  THREAD);
 323 
 324   KlassHandle superk_h(THREAD, superk);
 325 
 326   // Note: clean up of placeholders currently in callers of
 327   // resolve_super_or_fail - either at update_dictionary time
 328   // or on error
 329   {
 330   MutexLocker mu(SystemDictionary_lock, THREAD);
 331    PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, class_loader);
 332    if (probe != NULL) {
 333       probe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER);
 334    }
 335   }
 336   if (HAS_PENDING_EXCEPTION || superk_h() == NULL) {
 337     // can null superk
 338     superk_h = KlassHandle(THREAD, handle_resolution_exception(class_name, class_loader, protection_domain, true, superk_h, THREAD));
 339   }
 340 
 341   return superk_h();
 342 }
 343 
 344 void SystemDictionary::validate_protection_domain(instanceKlassHandle klass,
 345                                                   Handle class_loader,
 346                                                   Handle protection_domain,
 347                                                   TRAPS) {
 348   if(!has_checkPackageAccess()) return;
 349 
 350   // Now we have to call back to java to check if the initating class has access
 351   JavaValue result(T_VOID);
 352   if (TraceProtectionDomainVerification) {
 353     // Print out trace information
 354     tty->print_cr("Checking package access");
 355     tty->print(" - class loader:      "); class_loader()->print_value_on(tty);      tty->cr();
 356     tty->print(" - protection domain: "); protection_domain()->print_value_on(tty); tty->cr();
 357     tty->print(" - loading:           "); klass()->print_value_on(tty);             tty->cr();
 358   }
 359 
 360   assert(class_loader() != NULL, "should not have non-null protection domain for null classloader");
 361 
 362   KlassHandle system_loader(THREAD, SystemDictionary::classloader_klass());
 363   JavaCalls::call_special(&result,
 364                          class_loader,
 365                          system_loader,
 366                          vmSymbolHandles::checkPackageAccess_name(),
 367                          vmSymbolHandles::class_protectiondomain_signature(),
 368                          Handle(THREAD, klass->java_mirror()),
 369                          protection_domain,
 370                          THREAD);
 371 
 372   if (TraceProtectionDomainVerification) {
 373     if (HAS_PENDING_EXCEPTION) {
 374       tty->print_cr(" -> DENIED !!!!!!!!!!!!!!!!!!!!!");
 375     } else {
 376      tty->print_cr(" -> granted");
 377     }
 378     tty->cr();
 379   }
 380 
 381   if (HAS_PENDING_EXCEPTION) return;
 382 
 383   // If no exception has been thrown, we have validated the protection domain
 384   // Insert the protection domain of the initiating class into the set.
 385   {
 386     // We recalculate the entry here -- we've called out to java since
 387     // the last time it was calculated.
 388     symbolHandle kn(THREAD, klass->name());
 389     unsigned int d_hash = dictionary()->compute_hash(kn, class_loader);
 390     int d_index = dictionary()->hash_to_index(d_hash);
 391 
 392     MutexLocker mu(SystemDictionary_lock, THREAD);
 393     {
 394       // Note that we have an entry, and entries can be deleted only during GC,
 395       // so we cannot allow GC to occur while we're holding this entry.
 396 
 397       // We're using a No_Safepoint_Verifier to catch any place where we
 398       // might potentially do a GC at all.
 399       // SystemDictionary::do_unloading() asserts that classes are only
 400       // unloaded at a safepoint.
 401       No_Safepoint_Verifier nosafepoint;
 402       dictionary()->add_protection_domain(d_index, d_hash, klass, class_loader,
 403                                           protection_domain, THREAD);
 404     }
 405   }
 406 }
 407 
 408 // We only get here if this thread finds that another thread
 409 // has already claimed the placeholder token for the current operation,
 410 // but that other thread either never owned or gave up the
 411 // object lock
 412 // Waits on SystemDictionary_lock to indicate placeholder table updated
 413 // On return, caller must recheck placeholder table state
 414 //
 415 // We only get here if
 416 //  1) custom classLoader, i.e. not bootstrap classloader
 417 //  2) UnsyncloadClass not set
 418 //  3) custom classLoader has broken the class loader objectLock
 419 //     so another thread got here in parallel
 420 //
 421 // lockObject must be held.
 422 // Complicated dance due to lock ordering:
 423 // Must first release the classloader object lock to
 424 // allow initial definer to complete the class definition
 425 // and to avoid deadlock
 426 // Reclaim classloader lock object with same original recursion count
 427 // Must release SystemDictionary_lock after notify, since
 428 // class loader lock must be claimed before SystemDictionary_lock
 429 // to prevent deadlocks
 430 //
 431 // The notify allows applications that did an untimed wait() on
 432 // the classloader object lock to not hang.
 433 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
 434   assert_lock_strong(SystemDictionary_lock);
 435 
 436   bool calledholdinglock
 437       = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
 438   assert(calledholdinglock,"must hold lock for notify");
 439   assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
 440   ObjectSynchronizer::notifyall(lockObject, THREAD);
 441   intptr_t recursions =  ObjectSynchronizer::complete_exit(lockObject, THREAD);
 442   SystemDictionary_lock->wait();
 443   SystemDictionary_lock->unlock();
 444   ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
 445   SystemDictionary_lock->lock();
 446 }
 447 
 448 // If the class in is in the placeholder table, class loading is in progress
 449 // For cases where the application changes threads to load classes, it
 450 // is critical to ClassCircularity detection that we try loading
 451 // the superclass on the same thread internally, so we do parallel
 452 // super class loading here.
 453 // This also is critical in cases where the original thread gets stalled
 454 // even in non-circularity situations.
 455 // Note: only one thread can define the class, but multiple can resolve
 456 // Note: must call resolve_super_or_fail even if null super -
 457 // to force placeholder entry creation for this class for circularity detection
 458 // Caller must check for pending exception
 459 // Returns non-null klassOop if other thread has completed load
 460 // and we are done,
 461 // If return null klassOop and no pending exception, the caller must load the class
 462 instanceKlassHandle SystemDictionary::handle_parallel_super_load(
 463     symbolHandle name, symbolHandle superclassname, Handle class_loader,
 464     Handle protection_domain, Handle lockObject, TRAPS) {
 465 
 466   instanceKlassHandle nh = instanceKlassHandle(); // null Handle
 467   unsigned int d_hash = dictionary()->compute_hash(name, class_loader);
 468   int d_index = dictionary()->hash_to_index(d_hash);
 469   unsigned int p_hash = placeholders()->compute_hash(name, class_loader);
 470   int p_index = placeholders()->hash_to_index(p_hash);
 471 
 472   // superk is not used, resolve_super called for circularity check only
 473   // This code is reached in two situations. One if this thread
 474   // is loading the same class twice (e.g. ClassCircularity, or
 475   // java.lang.instrument).
 476   // The second is if another thread started the resolve_super first
 477   // and has not yet finished.
 478   // In both cases the original caller will clean up the placeholder
 479   // entry on error.
 480   klassOop superk = SystemDictionary::resolve_super_or_fail(name,
 481                                                           superclassname,
 482                                                           class_loader,
 483                                                           protection_domain,
 484                                                           true,
 485                                                           CHECK_(nh));
 486   // We don't redefine the class, so we just need to clean up if there
 487   // was not an error (don't want to modify any system dictionary
 488   // data structures).
 489   {
 490     MutexLocker mu(SystemDictionary_lock, THREAD);
 491     placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD);
 492     SystemDictionary_lock->notify_all();
 493   }
 494 
 495   // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
 496   // Serial class loaders and bootstrap classloader do wait for superclass loads
 497  if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
 498     MutexLocker mu(SystemDictionary_lock, THREAD);
 499     // Check if classloading completed while we were loading superclass or waiting
 500     klassOop check = find_class(d_index, d_hash, name, class_loader);
 501     if (check != NULL) {
 502       // Klass is already loaded, so just return it
 503       return(instanceKlassHandle(THREAD, check));
 504     } else {
 505       return nh;
 506     }
 507   }
 508 
 509   // must loop to both handle other placeholder updates
 510   // and spurious notifications
 511   bool super_load_in_progress = true;
 512   PlaceholderEntry* placeholder;
 513   while (super_load_in_progress) {
 514     MutexLocker mu(SystemDictionary_lock, THREAD);
 515     // Check if classloading completed while we were loading superclass or waiting
 516     klassOop check = find_class(d_index, d_hash, name, class_loader);
 517     if (check != NULL) {
 518       // Klass is already loaded, so just return it
 519       return(instanceKlassHandle(THREAD, check));
 520     } else {
 521       placeholder = placeholders()->get_entry(p_index, p_hash, name, class_loader);
 522       if (placeholder && placeholder->super_load_in_progress() ){
 523         // Before UnsyncloadClass:
 524         // We only get here if the application has released the
 525         // classloader lock when another thread was in the middle of loading a
 526         // superclass/superinterface for this class, and now
 527         // this thread is also trying to load this class.
 528         // To minimize surprises, the first thread that started to
 529         // load a class should be the one to complete the loading
 530         // with the classfile it initially expected.
 531         // This logic has the current thread wait once it has done
 532         // all the superclass/superinterface loading it can, until
 533         // the original thread completes the class loading or fails
 534         // If it completes we will use the resulting instanceKlass
 535         // which we will find below in the systemDictionary.
 536         // We also get here for parallel bootstrap classloader
 537         if (class_loader.is_null()) {
 538           SystemDictionary_lock->wait();
 539         } else {
 540           double_lock_wait(lockObject, THREAD);
 541         }
 542       } else {
 543         // If not in SD and not in PH, other thread's load must have failed
 544         super_load_in_progress = false;
 545       }
 546     }
 547   }
 548   return (nh);
 549 }
 550 
 551 
 552 klassOop SystemDictionary::resolve_instance_class_or_null(symbolHandle class_name, Handle class_loader, Handle protection_domain, TRAPS) {
 553   assert(class_name.not_null() && !FieldType::is_array(class_name()), "invalid class name");
 554   // First check to see if we should remove wrapping L and ;
 555   symbolHandle name;
 556   if (FieldType::is_obj(class_name())) {
 557     ResourceMark rm(THREAD);
 558     // Ignore wrapping L and ;.
 559     name = oopFactory::new_symbol_handle(class_name()->as_C_string() + 1, class_name()->utf8_length() - 2, CHECK_NULL);
 560   } else {
 561     name = class_name;
 562   }
 563 
 564   // UseNewReflection
 565   // Fix for 4474172; see evaluation for more details
 566   class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
 567 
 568   // Do lookup to see if class already exist and the protection domain
 569   // has the right access
 570   unsigned int d_hash = dictionary()->compute_hash(name, class_loader);
 571   int d_index = dictionary()->hash_to_index(d_hash);
 572   klassOop probe = dictionary()->find(d_index, d_hash, name, class_loader,
 573                                       protection_domain, THREAD);
 574   if (probe != NULL) return probe;
 575 
 576 
 577   // Non-bootstrap class loaders will call out to class loader and
 578   // define via jvm/jni_DefineClass which will acquire the
 579   // class loader object lock to protect against multiple threads
 580   // defining the class in parallel by accident.
 581   // This lock must be acquired here so the waiter will find
 582   // any successful result in the SystemDictionary and not attempt
 583   // the define
 584   // ParallelCapable Classloaders and the bootstrap classloader,
 585   // or all classloaders with UnsyncloadClass do not acquire lock here
 586   bool DoObjectLock = true;
 587   if (is_parallelCapable(class_loader)) {
 588     DoObjectLock = false;
 589   }
 590 
 591   unsigned int p_hash = placeholders()->compute_hash(name, class_loader);
 592   int p_index = placeholders()->hash_to_index(p_hash);
 593 
 594   // Class is not in SystemDictionary so we have to do loading.
 595   // Make sure we are synchronized on the class loader before we proceed
 596   Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
 597   check_loader_lock_contention(lockObject, THREAD);
 598   ObjectLocker ol(lockObject, THREAD, DoObjectLock);
 599 
 600   // Check again (after locking) if class already exist in SystemDictionary
 601   bool class_has_been_loaded   = false;
 602   bool super_load_in_progress  = false;
 603   bool havesupername = false;
 604   instanceKlassHandle k;
 605   PlaceholderEntry* placeholder;
 606   symbolHandle superclassname;
 607 
 608   {
 609     MutexLocker mu(SystemDictionary_lock, THREAD);
 610     klassOop check = find_class(d_index, d_hash, name, class_loader);
 611     if (check != NULL) {
 612       // Klass is already loaded, so just return it
 613       class_has_been_loaded = true;
 614       k = instanceKlassHandle(THREAD, check);
 615     } else {
 616       placeholder = placeholders()->get_entry(p_index, p_hash, name, class_loader);
 617       if (placeholder && placeholder->super_load_in_progress()) {
 618          super_load_in_progress = true;
 619          if (placeholder->havesupername() == true) {
 620            superclassname = symbolHandle(THREAD, placeholder->supername());
 621            havesupername = true;
 622          }
 623       }
 624     }
 625   }
 626 
 627   // If the class in is in the placeholder table, class loading is in progress
 628   if (super_load_in_progress && havesupername==true) {
 629     k = SystemDictionary::handle_parallel_super_load(name, superclassname,
 630         class_loader, protection_domain, lockObject, THREAD);
 631     if (HAS_PENDING_EXCEPTION) {
 632       return NULL;
 633     }
 634     if (!k.is_null()) {
 635       class_has_been_loaded = true;
 636     }
 637   }
 638 
 639   if (!class_has_been_loaded) {
 640 
 641     // add placeholder entry to record loading instance class
 642     // Five cases:
 643     // All cases need to prevent modifying bootclasssearchpath
 644     // in parallel with a classload of same classname
 645     // Redefineclasses uses existence of the placeholder for the duration
 646     // of the class load to prevent concurrent redefinition of not completely
 647     // defined classes.
 648     // case 1. traditional classloaders that rely on the classloader object lock
 649     //   - no other need for LOAD_INSTANCE
 650     // case 2. traditional classloaders that break the classloader object lock
 651     //    as a deadlock workaround. Detection of this case requires that
 652     //    this check is done while holding the classloader object lock,
 653     //    and that lock is still held when calling classloader's loadClass.
 654     //    For these classloaders, we ensure that the first requestor
 655     //    completes the load and other requestors wait for completion.
 656     // case 3. UnsyncloadClass - don't use objectLocker
 657     //    With this flag, we allow parallel classloading of a
 658     //    class/classloader pair
 659     // case4. Bootstrap classloader - don't own objectLocker
 660     //    This classloader supports parallelism at the classloader level,
 661     //    but only allows a single load of a class/classloader pair.
 662     //    No performance benefit and no deadlock issues.
 663     // case 5. parallelCapable user level classloaders - without objectLocker
 664     //    Allow parallel classloading of a class/classloader pair
 665     symbolHandle nullsymbolHandle;
 666     bool throw_circularity_error = false;
 667     {
 668       MutexLocker mu(SystemDictionary_lock, THREAD);
 669       if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
 670         PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, class_loader);
 671         if (oldprobe) {
 672           // only need check_seen_thread once, not on each loop
 673           // 6341374 java/lang/Instrument with -Xcomp
 674           if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
 675             throw_circularity_error = true;
 676           } else {
 677             // case 1: traditional: should never see load_in_progress.
 678             while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
 679 
 680               // case 4: bootstrap classloader: prevent futile classloading,
 681               // wait on first requestor
 682               if (class_loader.is_null()) {
 683                 SystemDictionary_lock->wait();
 684               } else {
 685               // case 2: traditional with broken classloader lock. wait on first
 686               // requestor.
 687                 double_lock_wait(lockObject, THREAD);
 688               }
 689               // Check if classloading completed while we were waiting
 690               klassOop check = find_class(d_index, d_hash, name, class_loader);
 691               if (check != NULL) {
 692                 // Klass is already loaded, so just return it
 693                 k = instanceKlassHandle(THREAD, check);
 694                 class_has_been_loaded = true;
 695               }
 696               // check if other thread failed to load and cleaned up
 697               oldprobe = placeholders()->get_entry(p_index, p_hash, name, class_loader);
 698             }
 699           }
 700         }
 701       }
 702       // All cases: add LOAD_INSTANCE
 703       // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try
 704       // LOAD_INSTANCE in parallel
 705       // add placeholder entry even if error - callers will remove on error
 706       if (!throw_circularity_error && !class_has_been_loaded) {
 707         PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, class_loader, PlaceholderTable::LOAD_INSTANCE, nullsymbolHandle, THREAD);
 708         // For class loaders that do not acquire the classloader object lock,
 709         // if they did not catch another thread holding LOAD_INSTANCE,
 710         // need a check analogous to the acquire ObjectLocker/find_class
 711         // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
 712         // one final check if the load has already completed
 713         // class loaders holding the ObjectLock shouldn't find the class here
 714         klassOop check = find_class(d_index, d_hash, name, class_loader);
 715         if (check != NULL) {
 716         // Klass is already loaded, so just return it
 717           k = instanceKlassHandle(THREAD, check);
 718           class_has_been_loaded = true;
 719           newprobe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE);
 720           placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD);
 721           SystemDictionary_lock->notify_all();
 722         }
 723       }
 724     }
 725     // must throw error outside of owning lock
 726     if (throw_circularity_error) {
 727       ResourceMark rm(THREAD);
 728       THROW_MSG_0(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
 729     }
 730 
 731     if (!class_has_been_loaded) {
 732 
 733       // Do actual loading
 734       k = load_instance_class(name, class_loader, THREAD);
 735 
 736       // For UnsyncloadClass only
 737       // If they got a linkageError, check if a parallel class load succeeded.
 738       // If it did, then for bytecode resolution the specification requires
 739       // that we return the same result we did for the other thread, i.e. the
 740       // successfully loaded instanceKlass
 741       // Should not get here for classloaders that support parallelism
 742       // with the new cleaner mechanism, even with AllowParallelDefineClass
 743       // Bootstrap goes through here to allow for an extra guarantee check
 744       if (UnsyncloadClass || (class_loader.is_null())) {
 745         if (k.is_null() && HAS_PENDING_EXCEPTION
 746           && PENDING_EXCEPTION->is_a(SystemDictionary::linkageError_klass())) {
 747           MutexLocker mu(SystemDictionary_lock, THREAD);
 748           klassOop check = find_class(d_index, d_hash, name, class_loader);
 749           if (check != NULL) {
 750             // Klass is already loaded, so just use it
 751             k = instanceKlassHandle(THREAD, check);
 752             CLEAR_PENDING_EXCEPTION;
 753             guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?");
 754           }
 755         }
 756       }
 757 
 758       // clean up placeholder entries for success or error
 759       // This cleans up LOAD_INSTANCE entries
 760       // It also cleans up LOAD_SUPER entries on errors from
 761       // calling load_instance_class
 762       {
 763         MutexLocker mu(SystemDictionary_lock, THREAD);
 764         PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name, class_loader);
 765         if (probe != NULL) {
 766           probe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE);
 767           placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD);
 768           SystemDictionary_lock->notify_all();
 769         }
 770       }
 771 
 772       // If everything was OK (no exceptions, no null return value), and
 773       // class_loader is NOT the defining loader, do a little more bookkeeping.
 774       if (!HAS_PENDING_EXCEPTION && !k.is_null() &&
 775         k->class_loader() != class_loader()) {
 776 
 777         check_constraints(d_index, d_hash, k, class_loader, false, THREAD);
 778 
 779         // Need to check for a PENDING_EXCEPTION again; check_constraints
 780         // can throw and doesn't use the CHECK macro.
 781         if (!HAS_PENDING_EXCEPTION) {
 782           { // Grabbing the Compile_lock prevents systemDictionary updates
 783             // during compilations.
 784             MutexLocker mu(Compile_lock, THREAD);
 785             update_dictionary(d_index, d_hash, p_index, p_hash,
 786                             k, class_loader, THREAD);
 787           }
 788           if (JvmtiExport::should_post_class_load()) {
 789             Thread *thread = THREAD;
 790             assert(thread->is_Java_thread(), "thread->is_Java_thread()");
 791             JvmtiExport::post_class_load((JavaThread *) thread, k());
 792           }
 793         }
 794       }
 795       if (HAS_PENDING_EXCEPTION || k.is_null()) {
 796         // On error, clean up placeholders
 797         {
 798           MutexLocker mu(SystemDictionary_lock, THREAD);
 799           placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD);
 800           SystemDictionary_lock->notify_all();
 801         }
 802         return NULL;
 803       }
 804     }
 805   }
 806 
 807 #ifdef ASSERT
 808   {
 809     Handle loader (THREAD, k->class_loader());
 810     MutexLocker mu(SystemDictionary_lock, THREAD);
 811     oop kk = find_class_or_placeholder(name, loader);
 812     assert(kk == k(), "should be present in dictionary");
 813   }
 814 #endif
 815 
 816   // return if the protection domain in NULL
 817   if (protection_domain() == NULL) return k();
 818 
 819   // Check the protection domain has the right access
 820   {
 821     MutexLocker mu(SystemDictionary_lock, THREAD);
 822     // Note that we have an entry, and entries can be deleted only during GC,
 823     // so we cannot allow GC to occur while we're holding this entry.
 824     // We're using a No_Safepoint_Verifier to catch any place where we
 825     // might potentially do a GC at all.
 826     // SystemDictionary::do_unloading() asserts that classes are only
 827     // unloaded at a safepoint.
 828     No_Safepoint_Verifier nosafepoint;
 829     if (dictionary()->is_valid_protection_domain(d_index, d_hash, name,
 830                                                  class_loader,
 831                                                  protection_domain)) {
 832       return k();
 833     }
 834   }
 835 
 836   // Verify protection domain. If it fails an exception is thrown
 837   validate_protection_domain(k, class_loader, protection_domain, CHECK_(klassOop(NULL)));
 838 
 839   return k();
 840 }
 841 
 842 
 843 // This routine does not lock the system dictionary.
 844 //
 845 // Since readers don't hold a lock, we must make sure that system
 846 // dictionary entries are only removed at a safepoint (when only one
 847 // thread is running), and are added to in a safe way (all links must
 848 // be updated in an MT-safe manner).
 849 //
 850 // Callers should be aware that an entry could be added just after
 851 // _dictionary->bucket(index) is read here, so the caller will not see
 852 // the new entry.
 853 
 854 klassOop SystemDictionary::find(symbolHandle class_name,
 855                                 Handle class_loader,
 856                                 Handle protection_domain,
 857                                 TRAPS) {
 858 
 859   // UseNewReflection
 860   // The result of this call should be consistent with the result
 861   // of the call to resolve_instance_class_or_null().
 862   // See evaluation 6790209 and 4474172 for more details.
 863   class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
 864 
 865   unsigned int d_hash = dictionary()->compute_hash(class_name, class_loader);
 866   int d_index = dictionary()->hash_to_index(d_hash);
 867 
 868   {
 869     // Note that we have an entry, and entries can be deleted only during GC,
 870     // so we cannot allow GC to occur while we're holding this entry.
 871     // We're using a No_Safepoint_Verifier to catch any place where we
 872     // might potentially do a GC at all.
 873     // SystemDictionary::do_unloading() asserts that classes are only
 874     // unloaded at a safepoint.
 875     No_Safepoint_Verifier nosafepoint;
 876     return dictionary()->find(d_index, d_hash, class_name, class_loader,
 877                               protection_domain, THREAD);
 878   }
 879 }
 880 
 881 
 882 // Look for a loaded instance or array klass by name.  Do not do any loading.
 883 // return NULL in case of error.
 884 klassOop SystemDictionary::find_instance_or_array_klass(symbolHandle class_name,
 885                                                         Handle class_loader,
 886                                                         Handle protection_domain,
 887                                                         TRAPS) {
 888   klassOop k = NULL;
 889   assert(class_name() != NULL, "class name must be non NULL");
 890 
 891   // Try to get one of the well-known klasses.
 892   if (LinkWellKnownClasses) {
 893     k = find_well_known_klass(class_name());
 894     if (k != NULL) {
 895       return k;
 896     }
 897   }
 898 
 899   if (FieldType::is_array(class_name())) {
 900     // The name refers to an array.  Parse the name.
 901     jint dimension;
 902     symbolOop object_key;
 903 
 904     // dimension and object_key are assigned as a side-effect of this call
 905     BasicType t = FieldType::get_array_info(class_name(), &dimension,
 906                                             &object_key, CHECK_(NULL));
 907     if (t != T_OBJECT) {
 908       k = Universe::typeArrayKlassObj(t);
 909     } else {
 910       symbolHandle h_key(THREAD, object_key);
 911       k = SystemDictionary::find(h_key, class_loader, protection_domain, THREAD);
 912     }
 913     if (k != NULL) {
 914       k = Klass::cast(k)->array_klass_or_null(dimension);
 915     }
 916   } else {
 917     k = find(class_name, class_loader, protection_domain, THREAD);
 918   }
 919   return k;
 920 }
 921 
 922 // Quick range check for names of well-known classes:
 923 static symbolOop wk_klass_name_limits[2] = {NULL, NULL};
 924 
 925 #ifndef PRODUCT
 926 static int find_wkk_calls, find_wkk_probes, find_wkk_wins;
 927 // counts for "hello world": 3983, 1616, 1075
 928 //  => 60% hit after limit guard, 25% total win rate
 929 #endif
 930 
 931 klassOop SystemDictionary::find_well_known_klass(symbolOop class_name) {
 932   // A bounds-check on class_name will quickly get a negative result.
 933   NOT_PRODUCT(find_wkk_calls++);
 934   if (class_name >= wk_klass_name_limits[0] &&
 935       class_name <= wk_klass_name_limits[1]) {
 936     NOT_PRODUCT(find_wkk_probes++);
 937     vmSymbols::SID sid = vmSymbols::find_sid(class_name);
 938     if (sid != vmSymbols::NO_SID) {
 939       klassOop k = NULL;
 940       switch (sid) {
 941         #define WK_KLASS_CASE(name, symbol, ignore_option) \
 942         case vmSymbols::VM_SYMBOL_ENUM_NAME(symbol): \
 943           k = WK_KLASS(name); break;
 944         WK_KLASSES_DO(WK_KLASS_CASE)
 945         #undef WK_KLASS_CASE
 946       }
 947       NOT_PRODUCT(if (k != NULL)  find_wkk_wins++);
 948       return k;
 949     }
 950   }
 951   return NULL;
 952 }
 953 
 954 // Note: this method is much like resolve_from_stream, but
 955 // updates no supplemental data structures.
 956 // TODO consolidate the two methods with a helper routine?
 957 klassOop SystemDictionary::parse_stream(symbolHandle class_name,
 958                                         Handle class_loader,
 959                                         Handle protection_domain,
 960                                         ClassFileStream* st,
 961                                         KlassHandle host_klass,
 962                                         GrowableArray<Handle>* cp_patches,
 963                                         TRAPS) {
 964   symbolHandle parsed_name;
 965 
 966   // Parse the stream. Note that we do this even though this klass might
 967   // already be present in the SystemDictionary, otherwise we would not
 968   // throw potential ClassFormatErrors.
 969   //
 970   // Note: "name" is updated.
 971   // Further note:  a placeholder will be added for this class when
 972   //   super classes are loaded (resolve_super_or_fail). We expect this
 973   //   to be called for all classes but java.lang.Object; and we preload
 974   //   java.lang.Object through resolve_or_fail, not this path.
 975 
 976   instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
 977                                                              class_loader,
 978                                                              protection_domain,
 979                                                              host_klass,
 980                                                              cp_patches,
 981                                                              parsed_name,
 982                                                              true,
 983                                                              THREAD);
 984 
 985 
 986   // We don't redefine the class, so we just need to clean up whether there
 987   // was an error or not (don't want to modify any system dictionary
 988   // data structures).
 989   // Parsed name could be null if we threw an error before we got far
 990   // enough along to parse it -- in that case, there is nothing to clean up.
 991   if (!parsed_name.is_null()) {
 992     unsigned int p_hash = placeholders()->compute_hash(parsed_name,
 993                                                        class_loader);
 994     int p_index = placeholders()->hash_to_index(p_hash);
 995     {
 996     MutexLocker mu(SystemDictionary_lock, THREAD);
 997     placeholders()->find_and_remove(p_index, p_hash, parsed_name, class_loader, THREAD);
 998     SystemDictionary_lock->notify_all();
 999     }
1000   }
1001 
1002   if (host_klass.not_null() && k.not_null()) {
1003     assert(AnonymousClasses, "");
1004     // If it's anonymous, initialize it now, since nobody else will.
1005     k->set_host_klass(host_klass());
1006 
1007     {
1008       MutexLocker mu_r(Compile_lock, THREAD);
1009 
1010       // Add to class hierarchy, initialize vtables, and do possible
1011       // deoptimizations.
1012       add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1013 
1014       // But, do not add to system dictionary.
1015     }
1016 
1017     k->eager_initialize(THREAD);
1018 
1019     // notify jvmti
1020     if (JvmtiExport::should_post_class_load()) {
1021         assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1022         JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1023     }
1024   }
1025 
1026   return k();
1027 }
1028 
1029 // Add a klass to the system from a stream (called by jni_DefineClass and
1030 // JVM_DefineClass).
1031 // Note: class_name can be NULL. In that case we do not know the name of
1032 // the class until we have parsed the stream.
1033 
1034 klassOop SystemDictionary::resolve_from_stream(symbolHandle class_name,
1035                                                Handle class_loader,
1036                                                Handle protection_domain,
1037                                                ClassFileStream* st,
1038                                                bool verify,
1039                                                TRAPS) {
1040 
1041   // Classloaders that support parallelism, e.g. bootstrap classloader,
1042   // or all classloaders with UnsyncloadClass do not acquire lock here
1043   bool DoObjectLock = true;
1044   if (is_parallelCapable(class_loader)) {
1045     DoObjectLock = false;
1046   }
1047 
1048   // Make sure we are synchronized on the class loader before we proceed
1049   Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1050   check_loader_lock_contention(lockObject, THREAD);
1051   ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1052 
1053   symbolHandle parsed_name;
1054 
1055   // Parse the stream. Note that we do this even though this klass might
1056   // already be present in the SystemDictionary, otherwise we would not
1057   // throw potential ClassFormatErrors.
1058   //
1059   // Note: "name" is updated.
1060   // Further note:  a placeholder will be added for this class when
1061   //   super classes are loaded (resolve_super_or_fail). We expect this
1062   //   to be called for all classes but java.lang.Object; and we preload
1063   //   java.lang.Object through resolve_or_fail, not this path.
1064 
1065   instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
1066                                                              class_loader,
1067                                                              protection_domain,
1068                                                              parsed_name,
1069                                                              verify,
1070                                                              THREAD);
1071 
1072   const char* pkg = "java/";
1073   if (!HAS_PENDING_EXCEPTION &&
1074       !class_loader.is_null() &&
1075       !parsed_name.is_null() &&
1076       !strncmp((const char*)parsed_name->bytes(), pkg, strlen(pkg))) {
1077     // It is illegal to define classes in the "java." package from
1078     // JVM_DefineClass or jni_DefineClass unless you're the bootclassloader
1079     ResourceMark rm(THREAD);
1080     char* name = parsed_name->as_C_string();
1081     char* index = strrchr(name, '/');
1082     *index = '\0'; // chop to just the package name
1083     while ((index = strchr(name, '/')) != NULL) {
1084       *index = '.'; // replace '/' with '.' in package name
1085     }
1086     const char* fmt = "Prohibited package name: %s";
1087     size_t len = strlen(fmt) + strlen(name);
1088     char* message = NEW_RESOURCE_ARRAY(char, len);
1089     jio_snprintf(message, len, fmt, name);
1090     Exceptions::_throw_msg(THREAD_AND_LOCATION,
1091       vmSymbols::java_lang_SecurityException(), message);
1092   }
1093 
1094   if (!HAS_PENDING_EXCEPTION) {
1095     assert(!parsed_name.is_null(), "Sanity");
1096     assert(class_name.is_null() || class_name() == parsed_name(),
1097            "name mismatch");
1098     // Verification prevents us from creating names with dots in them, this
1099     // asserts that that's the case.
1100     assert(is_internal_format(parsed_name),
1101            "external class name format used internally");
1102 
1103     // Add class just loaded
1104     // If a class loader supports parallel classloading handle parallel define requests
1105     // find_or_define_instance_class may return a different instanceKlass
1106     if (is_parallelCapable(class_loader)) {
1107       k = find_or_define_instance_class(class_name, class_loader, k, THREAD);
1108     } else {
1109       define_instance_class(k, THREAD);
1110     }
1111   }
1112 
1113   // If parsing the class file or define_instance_class failed, we
1114   // need to remove the placeholder added on our behalf. But we
1115   // must make sure parsed_name is valid first (it won't be if we had
1116   // a format error before the class was parsed far enough to
1117   // find the name).
1118   if (HAS_PENDING_EXCEPTION && !parsed_name.is_null()) {
1119     unsigned int p_hash = placeholders()->compute_hash(parsed_name,
1120                                                        class_loader);
1121     int p_index = placeholders()->hash_to_index(p_hash);
1122     {
1123     MutexLocker mu(SystemDictionary_lock, THREAD);
1124     placeholders()->find_and_remove(p_index, p_hash, parsed_name, class_loader, THREAD);
1125     SystemDictionary_lock->notify_all();
1126     }
1127     return NULL;
1128   }
1129 
1130   // Make sure that we didn't leave a place holder in the
1131   // SystemDictionary; this is only done on success
1132   debug_only( {
1133     if (!HAS_PENDING_EXCEPTION) {
1134       assert(!parsed_name.is_null(), "parsed_name is still null?");
1135       symbolHandle h_name   (THREAD, k->name());
1136       Handle h_loader (THREAD, k->class_loader());
1137 
1138       MutexLocker mu(SystemDictionary_lock, THREAD);
1139 
1140       oop check = find_class_or_placeholder(parsed_name, class_loader);
1141       assert(check == k(), "should be present in the dictionary");
1142 
1143       oop check2 = find_class_or_placeholder(h_name, h_loader);
1144       assert(check == check2, "name inconsistancy in SystemDictionary");
1145     }
1146   } );
1147 
1148   return k();
1149 }
1150 
1151 
1152 void SystemDictionary::set_shared_dictionary(HashtableBucket* t, int length,
1153                                              int number_of_entries) {
1154   assert(length == _nof_buckets * sizeof(HashtableBucket),
1155          "bad shared dictionary size.");
1156   _shared_dictionary = new Dictionary(_nof_buckets, t, number_of_entries);
1157 }
1158 
1159 
1160 // If there is a shared dictionary, then find the entry for the
1161 // given shared system class, if any.
1162 
1163 klassOop SystemDictionary::find_shared_class(symbolHandle class_name) {
1164   if (shared_dictionary() != NULL) {
1165     unsigned int d_hash = dictionary()->compute_hash(class_name, Handle());
1166     int d_index = dictionary()->hash_to_index(d_hash);
1167     return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1168   } else {
1169     return NULL;
1170   }
1171 }
1172 
1173 
1174 // Load a class from the shared spaces (found through the shared system
1175 // dictionary).  Force the superclass and all interfaces to be loaded.
1176 // Update the class definition to include sibling classes and no
1177 // subclasses (yet).  [Classes in the shared space are not part of the
1178 // object hierarchy until loaded.]
1179 
1180 instanceKlassHandle SystemDictionary::load_shared_class(
1181                  symbolHandle class_name, Handle class_loader, TRAPS) {
1182   instanceKlassHandle ik (THREAD, find_shared_class(class_name));
1183   return load_shared_class(ik, class_loader, THREAD);
1184 }
1185 
1186 // Note well!  Changes to this method may affect oop access order
1187 // in the shared archive.  Please take care to not make changes that
1188 // adversely affect cold start time by changing the oop access order
1189 // that is specified in dump.cpp MarkAndMoveOrderedReadOnly and
1190 // MarkAndMoveOrderedReadWrite closures.
1191 instanceKlassHandle SystemDictionary::load_shared_class(
1192                  instanceKlassHandle ik, Handle class_loader, TRAPS) {
1193   assert(class_loader.is_null(), "non-null classloader for shared class?");
1194   if (ik.not_null()) {
1195     instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1196     symbolHandle class_name(THREAD, ik->name());
1197 
1198     // Found the class, now load the superclass and interfaces.  If they
1199     // are shared, add them to the main system dictionary and reset
1200     // their hierarchy references (supers, subs, and interfaces).
1201 
1202     if (ik->super() != NULL) {
1203       symbolHandle cn(THREAD, ik->super()->klass_part()->name());
1204       resolve_super_or_fail(class_name, cn,
1205                             class_loader, Handle(), true, CHECK_(nh));
1206     }
1207 
1208     objArrayHandle interfaces (THREAD, ik->local_interfaces());
1209     int num_interfaces = interfaces->length();
1210     for (int index = 0; index < num_interfaces; index++) {
1211       klassOop k = klassOop(interfaces->obj_at(index));
1212 
1213       // Note: can not use instanceKlass::cast here because
1214       // interfaces' instanceKlass's C++ vtbls haven't been
1215       // reinitialized yet (they will be once the interface classes
1216       // are loaded)
1217       symbolHandle name (THREAD, k->klass_part()->name());
1218       resolve_super_or_fail(class_name, name, class_loader, Handle(), false, CHECK_(nh));
1219     }
1220 
1221     // Adjust methods to recover missing data.  They need addresses for
1222     // interpreter entry points and their default native method address
1223     // must be reset.
1224 
1225     // Updating methods must be done under a lock so multiple
1226     // threads don't update these in parallel
1227     // Shared classes are all currently loaded by the bootstrap
1228     // classloader, so this will never cause a deadlock on
1229     // a custom class loader lock.
1230 
1231     {
1232       Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1233       check_loader_lock_contention(lockObject, THREAD);
1234       ObjectLocker ol(lockObject, THREAD, true);
1235 
1236       objArrayHandle methods (THREAD, ik->methods());
1237       int num_methods = methods->length();
1238       for (int index2 = 0; index2 < num_methods; ++index2) {
1239         methodHandle m(THREAD, methodOop(methods->obj_at(index2)));
1240         m()->link_method(m, CHECK_(nh));
1241       }
1242     }
1243 
1244     if (TraceClassLoading) {
1245       ResourceMark rm;
1246       tty->print("[Loaded %s", ik->external_name());
1247       tty->print(" from shared objects file");
1248       tty->print_cr("]");
1249     }
1250     // notify a class loaded from shared object
1251     ClassLoadingService::notify_class_loaded(instanceKlass::cast(ik()),
1252                                              true /* shared class */);
1253   }
1254   return ik;
1255 }
1256 
1257 #ifdef KERNEL
1258 // Some classes on the bootstrap class path haven't been installed on the
1259 // system yet.  Call the DownloadManager method to make them appear in the
1260 // bootstrap class path and try again to load the named class.
1261 // Note that with delegation class loaders all classes in another loader will
1262 // first try to call this so it'd better be fast!!
1263 static instanceKlassHandle download_and_retry_class_load(
1264                                                     symbolHandle class_name,
1265                                                     TRAPS) {
1266 
1267   klassOop dlm = SystemDictionary::sun_jkernel_DownloadManager_klass();
1268   instanceKlassHandle nk;
1269 
1270   // If download manager class isn't loaded just return.
1271   if (dlm == NULL) return nk;
1272 
1273   { HandleMark hm(THREAD);
1274     ResourceMark rm(THREAD);
1275     Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nk));
1276     Handle class_string = java_lang_String::externalize_classname(s, CHECK_(nk));
1277 
1278     // return value
1279     JavaValue result(T_OBJECT);
1280 
1281     // Call the DownloadManager.  We assume that it has a lock because
1282     // multiple classes could be not found and downloaded at the same time.
1283     // class sun.misc.DownloadManager;
1284     // public static String getBootClassPathEntryForClass(String className);
1285     JavaCalls::call_static(&result,
1286                        KlassHandle(THREAD, dlm),
1287                        vmSymbolHandles::getBootClassPathEntryForClass_name(),
1288                        vmSymbolHandles::string_string_signature(),
1289                        class_string,
1290                        CHECK_(nk));
1291 
1292     // Get result.string and add to bootclasspath
1293     assert(result.get_type() == T_OBJECT, "just checking");
1294     oop obj = (oop) result.get_jobject();
1295     if (obj == NULL) { return nk; }
1296 
1297     Handle h_obj(THREAD, obj);
1298     char* new_class_name = java_lang_String::as_platform_dependent_str(h_obj,
1299                                                                   CHECK_(nk));
1300 
1301     // lock the loader
1302     // we use this lock because JVMTI does.
1303     Handle loader_lock(THREAD, SystemDictionary::system_loader_lock());
1304 
1305     ObjectLocker ol(loader_lock, THREAD);
1306     // add the file to the bootclasspath
1307     ClassLoader::update_class_path_entry_list(new_class_name, true);
1308   } // end HandleMark
1309 
1310   if (TraceClassLoading) {
1311     ClassLoader::print_bootclasspath();
1312   }
1313   return ClassLoader::load_classfile(class_name, CHECK_(nk));
1314 }
1315 #endif // KERNEL
1316 
1317 
1318 instanceKlassHandle SystemDictionary::load_instance_class(symbolHandle class_name, Handle class_loader, TRAPS) {
1319   instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1320   if (class_loader.is_null()) {
1321 
1322     // Search the shared system dictionary for classes preloaded into the
1323     // shared spaces.
1324     instanceKlassHandle k;
1325     {
1326       PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1327       k = load_shared_class(class_name, class_loader, THREAD);
1328     }
1329 
1330     if (k.is_null()) {
1331       // Use VM class loader
1332       PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1333       k = ClassLoader::load_classfile(class_name, CHECK_(nh));
1334     }
1335 
1336 #ifdef KERNEL
1337     // If the VM class loader has failed to load the class, call the
1338     // DownloadManager class to make it magically appear on the classpath
1339     // and try again.  This is only configured with the Kernel VM.
1340     if (k.is_null()) {
1341       k = download_and_retry_class_load(class_name, CHECK_(nh));
1342     }
1343 #endif // KERNEL
1344 
1345     // find_or_define_instance_class may return a different instanceKlass
1346     if (!k.is_null()) {
1347       k = find_or_define_instance_class(class_name, class_loader, k, CHECK_(nh));
1348     }
1349     return k;
1350   } else {
1351     // Use user specified class loader to load class. Call loadClass operation on class_loader.
1352     ResourceMark rm(THREAD);
1353 
1354     assert(THREAD->is_Java_thread(), "must be a JavaThread");
1355     JavaThread* jt = (JavaThread*) THREAD;
1356 
1357     PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1358                                ClassLoader::perf_app_classload_selftime(),
1359                                ClassLoader::perf_app_classload_count(),
1360                                jt->get_thread_stat()->perf_recursion_counts_addr(),
1361                                jt->get_thread_stat()->perf_timers_addr(),
1362                                PerfClassTraceTime::CLASS_LOAD);
1363 
1364     Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nh));
1365     // Translate to external class name format, i.e., convert '/' chars to '.'
1366     Handle string = java_lang_String::externalize_classname(s, CHECK_(nh));
1367 
1368     JavaValue result(T_OBJECT);
1369 
1370     KlassHandle spec_klass (THREAD, SystemDictionary::classloader_klass());
1371 
1372     // Call public unsynchronized loadClass(String) directly for all class loaders
1373     // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will
1374     // acquire a class-name based lock rather than the class loader object lock.
1375     // JDK < 7 already acquire the class loader lock in loadClass(String, boolean),
1376     // so the call to loadClassInternal() was not required.
1377     //
1378     // UnsyncloadClass flag means both call loadClass(String) and do
1379     // not acquire the class loader lock even for class loaders that are
1380     // not parallelCapable. This was a risky transitional
1381     // flag for diagnostic purposes only. It is risky to call
1382     // custom class loaders without synchronization.
1383     // WARNING If a custom class loader does NOT synchronizer findClass, or callers of
1384     // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field.
1385     // Do NOT assume this will be supported in future releases.
1386     //
1387     // Added MustCallLoadClassInternal in case we discover in the field
1388     // a customer that counts on this call
1389     if (MustCallLoadClassInternal && has_loadClassInternal()) {
1390       JavaCalls::call_special(&result,
1391                               class_loader,
1392                               spec_klass,
1393                               vmSymbolHandles::loadClassInternal_name(),
1394                               vmSymbolHandles::string_class_signature(),
1395                               string,
1396                               CHECK_(nh));
1397     } else {
1398       JavaCalls::call_virtual(&result,
1399                               class_loader,
1400                               spec_klass,
1401                               vmSymbolHandles::loadClass_name(),
1402                               vmSymbolHandles::string_class_signature(),
1403                               string,
1404                               CHECK_(nh));
1405     }
1406 
1407     assert(result.get_type() == T_OBJECT, "just checking");
1408     oop obj = (oop) result.get_jobject();
1409 
1410     // Primitive classes return null since forName() can not be
1411     // used to obtain any of the Class objects representing primitives or void
1412     if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1413       instanceKlassHandle k =
1414                 instanceKlassHandle(THREAD, java_lang_Class::as_klassOop(obj));
1415       // For user defined Java class loaders, check that the name returned is
1416       // the same as that requested.  This check is done for the bootstrap
1417       // loader when parsing the class file.
1418       if (class_name() == k->name()) {
1419         return k;
1420       }
1421     }
1422     // Class is not found or has the wrong name, return NULL
1423     return nh;
1424   }
1425 }
1426 
1427 void SystemDictionary::define_instance_class(instanceKlassHandle k, TRAPS) {
1428 
1429   Handle class_loader_h(THREAD, k->class_loader());
1430 
1431  // for bootstrap and other parallel classloaders don't acquire lock,
1432  // use placeholder token
1433  // If a parallelCapable class loader calls define_instance_class instead of
1434  // find_or_define_instance_class to get here, we have a timing
1435  // hole with systemDictionary updates and check_constraints
1436  if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1437     assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1438          compute_loader_lock_object(class_loader_h, THREAD)),
1439          "define called without lock");
1440   }
1441 
1442   // Check class-loading constraints. Throw exception if violation is detected.
1443   // Grabs and releases SystemDictionary_lock
1444   // The check_constraints/find_class call and update_dictionary sequence
1445   // must be "atomic" for a specific class/classloader pair so we never
1446   // define two different instanceKlasses for that class/classloader pair.
1447   // Existing classloaders will call define_instance_class with the
1448   // classloader lock held
1449   // Parallel classloaders will call find_or_define_instance_class
1450   // which will require a token to perform the define class
1451   symbolHandle name_h(THREAD, k->name());
1452   unsigned int d_hash = dictionary()->compute_hash(name_h, class_loader_h);
1453   int d_index = dictionary()->hash_to_index(d_hash);
1454   check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK);
1455 
1456   // Register class just loaded with class loader (placed in Vector)
1457   // Note we do this before updating the dictionary, as this can
1458   // fail with an OutOfMemoryError (if it does, we will *not* put this
1459   // class in the dictionary and will not update the class hierarchy).
1460   if (k->class_loader() != NULL) {
1461     methodHandle m(THREAD, Universe::loader_addClass_method());
1462     JavaValue result(T_VOID);
1463     JavaCallArguments args(class_loader_h);
1464     args.push_oop(Handle(THREAD, k->java_mirror()));
1465     JavaCalls::call(&result, m, &args, CHECK);
1466   }
1467 
1468   // Add the new class. We need recompile lock during update of CHA.
1469   {
1470     unsigned int p_hash = placeholders()->compute_hash(name_h, class_loader_h);
1471     int p_index = placeholders()->hash_to_index(p_hash);
1472 
1473     MutexLocker mu_r(Compile_lock, THREAD);
1474 
1475     // Add to class hierarchy, initialize vtables, and do possible
1476     // deoptimizations.
1477     add_to_hierarchy(k, CHECK); // No exception, but can block
1478 
1479     // Add to systemDictionary - so other classes can see it.
1480     // Grabs and releases SystemDictionary_lock
1481     update_dictionary(d_index, d_hash, p_index, p_hash,
1482                       k, class_loader_h, THREAD);
1483   }
1484   k->eager_initialize(THREAD);
1485 
1486   // notify jvmti
1487   if (JvmtiExport::should_post_class_load()) {
1488       assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1489       JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1490 
1491   }
1492 }
1493 
1494 // Support parallel classloading
1495 // All parallel class loaders, including bootstrap classloader
1496 // lock a placeholder entry for this class/class_loader pair
1497 // to allow parallel defines of different classes for this class loader
1498 // With AllowParallelDefine flag==true, in case they do not synchronize around
1499 // FindLoadedClass/DefineClass, calls, we check for parallel
1500 // loading for them, wait if a defineClass is in progress
1501 // and return the initial requestor's results
1502 // This flag does not apply to the bootstrap classloader.
1503 // With AllowParallelDefine flag==false, call through to define_instance_class
1504 // which will throw LinkageError: duplicate class definition.
1505 // False is the requested default.
1506 // For better performance, the class loaders should synchronize
1507 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1508 // potentially waste time reading and parsing the bytestream.
1509 // Note: VM callers should ensure consistency of k/class_name,class_loader
1510 instanceKlassHandle SystemDictionary::find_or_define_instance_class(symbolHandle class_name, Handle class_loader, instanceKlassHandle k, TRAPS) {
1511 
1512   instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1513   symbolHandle name_h(THREAD, k->name()); // passed in class_name may be null
1514 
1515   unsigned int d_hash = dictionary()->compute_hash(name_h, class_loader);
1516   int d_index = dictionary()->hash_to_index(d_hash);
1517 
1518 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1519   unsigned int p_hash = placeholders()->compute_hash(name_h, class_loader);
1520   int p_index = placeholders()->hash_to_index(p_hash);
1521   PlaceholderEntry* probe;
1522 
1523   {
1524     MutexLocker mu(SystemDictionary_lock, THREAD);
1525     // First check if class already defined
1526     if (UnsyncloadClass || (is_parallelDefine(class_loader))) {
1527       klassOop check = find_class(d_index, d_hash, name_h, class_loader);
1528       if (check != NULL) {
1529         return(instanceKlassHandle(THREAD, check));
1530       }
1531     }
1532 
1533     // Acquire define token for this class/classloader
1534     symbolHandle nullsymbolHandle;
1535     probe = placeholders()->find_and_add(p_index, p_hash, name_h, class_loader, PlaceholderTable::DEFINE_CLASS, nullsymbolHandle, THREAD);
1536     // Wait if another thread defining in parallel
1537     // All threads wait - even those that will throw duplicate class: otherwise
1538     // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1539     // if other thread has not finished updating dictionary
1540     while (probe->definer() != NULL) {
1541       SystemDictionary_lock->wait();
1542     }
1543     // Only special cases allow parallel defines and can use other thread's results
1544     // Other cases fall through, and may run into duplicate defines
1545     // caught by finding an entry in the SystemDictionary
1546     if ((UnsyncloadClass || is_parallelDefine(class_loader)) && (probe->instanceKlass() != NULL)) {
1547         probe->remove_seen_thread(THREAD, PlaceholderTable::DEFINE_CLASS);
1548         placeholders()->find_and_remove(p_index, p_hash, name_h, class_loader, THREAD);
1549         SystemDictionary_lock->notify_all();
1550 #ifdef ASSERT
1551         klassOop check = find_class(d_index, d_hash, name_h, class_loader);
1552         assert(check != NULL, "definer missed recording success");
1553 #endif
1554         return(instanceKlassHandle(THREAD, probe->instanceKlass()));
1555     } else {
1556       // This thread will define the class (even if earlier thread tried and had an error)
1557       probe->set_definer(THREAD);
1558     }
1559   }
1560 
1561   define_instance_class(k, THREAD);
1562 
1563   Handle linkage_exception = Handle(); // null handle
1564 
1565   // definer must notify any waiting threads
1566   {
1567     MutexLocker mu(SystemDictionary_lock, THREAD);
1568     PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, class_loader);
1569     assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1570     if (probe != NULL) {
1571       if (HAS_PENDING_EXCEPTION) {
1572         linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1573         CLEAR_PENDING_EXCEPTION;
1574       } else {
1575         probe->set_instanceKlass(k());
1576       }
1577       probe->set_definer(NULL);
1578       probe->remove_seen_thread(THREAD, PlaceholderTable::DEFINE_CLASS);
1579       placeholders()->find_and_remove(p_index, p_hash, name_h, class_loader, THREAD);
1580       SystemDictionary_lock->notify_all();
1581     }
1582   }
1583 
1584   // Can't throw exception while holding lock due to rank ordering
1585   if (linkage_exception() != NULL) {
1586     THROW_OOP_(linkage_exception(), nh); // throws exception and returns
1587   }
1588 
1589   return k;
1590 }
1591 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1592   // If class_loader is NULL we synchronize on _system_loader_lock_obj
1593   if (class_loader.is_null()) {
1594     return Handle(THREAD, _system_loader_lock_obj);
1595   } else {
1596     return class_loader;
1597   }
1598 }
1599 
1600 // This method is added to check how often we have to wait to grab loader
1601 // lock. The results are being recorded in the performance counters defined in
1602 // ClassLoader::_sync_systemLoaderLockContentionRate and
1603 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1604 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1605   if (!UsePerfData) {
1606     return;
1607   }
1608 
1609   assert(!loader_lock.is_null(), "NULL lock object");
1610 
1611   if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1612       == ObjectSynchronizer::owner_other) {
1613     // contention will likely happen, so increment the corresponding
1614     // contention counter.
1615     if (loader_lock() == _system_loader_lock_obj) {
1616       ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1617     } else {
1618       ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1619     }
1620   }
1621 }
1622 
1623 // ----------------------------------------------------------------------------
1624 // Lookup
1625 
1626 klassOop SystemDictionary::find_class(int index, unsigned int hash,
1627                                       symbolHandle class_name,
1628                                       Handle class_loader) {
1629   assert_locked_or_safepoint(SystemDictionary_lock);
1630   assert (index == dictionary()->index_for(class_name, class_loader),
1631           "incorrect index?");
1632 
1633   klassOop k = dictionary()->find_class(index, hash, class_name, class_loader);
1634   return k;
1635 }
1636 
1637 
1638 // Basic find on classes in the midst of being loaded
1639 symbolOop SystemDictionary::find_placeholder(int index, unsigned int hash,
1640                                              symbolHandle class_name,
1641                                              Handle class_loader) {
1642   assert_locked_or_safepoint(SystemDictionary_lock);
1643 
1644   return placeholders()->find_entry(index, hash, class_name, class_loader);
1645 }
1646 
1647 
1648 // Used for assertions and verification only
1649 oop SystemDictionary::find_class_or_placeholder(symbolHandle class_name,
1650                                                 Handle class_loader) {
1651   #ifndef ASSERT
1652   guarantee(VerifyBeforeGC   ||
1653             VerifyDuringGC   ||
1654             VerifyBeforeExit ||
1655             VerifyAfterGC, "too expensive");
1656   #endif
1657   assert_locked_or_safepoint(SystemDictionary_lock);
1658   symbolOop class_name_ = class_name();
1659   oop class_loader_ = class_loader();
1660 
1661   // First look in the loaded class array
1662   unsigned int d_hash = dictionary()->compute_hash(class_name, class_loader);
1663   int d_index = dictionary()->hash_to_index(d_hash);
1664   oop lookup = find_class(d_index, d_hash, class_name, class_loader);
1665 
1666   if (lookup == NULL) {
1667     // Next try the placeholders
1668     unsigned int p_hash = placeholders()->compute_hash(class_name,class_loader);
1669     int p_index = placeholders()->hash_to_index(p_hash);
1670     lookup = find_placeholder(p_index, p_hash, class_name, class_loader);
1671   }
1672 
1673   return lookup;
1674 }
1675 
1676 
1677 // Get the next class in the diictionary.
1678 klassOop SystemDictionary::try_get_next_class() {
1679   return dictionary()->try_get_next_class();
1680 }
1681 
1682 
1683 // ----------------------------------------------------------------------------
1684 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1685 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1686 // before a new class is used.
1687 
1688 void SystemDictionary::add_to_hierarchy(instanceKlassHandle k, TRAPS) {
1689   assert(k.not_null(), "just checking");
1690   // Link into hierachy. Make sure the vtables are initialized before linking into
1691   k->append_to_sibling_list();                    // add to superklass/sibling list
1692   k->process_interfaces(THREAD);                  // handle all "implements" declarations
1693   k->set_init_state(instanceKlass::loaded);
1694   // Now flush all code that depended on old class hierarchy.
1695   // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1696   // Also, first reinitialize vtable because it may have gotten out of synch
1697   // while the new class wasn't connected to the class hierarchy.
1698   Universe::flush_dependents_on(k);
1699 }
1700 
1701 
1702 // ----------------------------------------------------------------------------
1703 // GC support
1704 
1705 // Following roots during mark-sweep is separated in two phases.
1706 //
1707 // The first phase follows preloaded classes and all other system
1708 // classes, since these will never get unloaded anyway.
1709 //
1710 // The second phase removes (unloads) unreachable classes from the
1711 // system dictionary and follows the remaining classes' contents.
1712 
1713 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1714   // Follow preloaded classes/mirrors and system loader object
1715   blk->do_oop(&_java_system_loader);
1716   preloaded_oops_do(blk);
1717   always_strong_classes_do(blk);
1718 }
1719 
1720 
1721 void SystemDictionary::always_strong_classes_do(OopClosure* blk) {
1722   // Follow all system classes and temporary placeholders in dictionary
1723   dictionary()->always_strong_classes_do(blk);
1724 
1725   // Placeholders. These are *always* strong roots, as they
1726   // represent classes we're actively loading.
1727   placeholders_do(blk);
1728 
1729   // Visit extra methods
1730   if (invoke_method_table() != NULL)
1731     invoke_method_table()->oops_do(blk);
1732 
1733   // Loader constraints. We must keep the symbolOop used in the name alive.
1734   constraints()->always_strong_classes_do(blk);
1735 
1736   // Resolution errors keep the symbolOop for the error alive
1737   resolution_errors()->always_strong_classes_do(blk);
1738 }
1739 
1740 
1741 void SystemDictionary::placeholders_do(OopClosure* blk) {
1742   placeholders()->oops_do(blk);
1743 }
1744 
1745 
1746 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive) {
1747   bool result = dictionary()->do_unloading(is_alive);
1748   constraints()->purge_loader_constraints(is_alive);
1749   resolution_errors()->purge_resolution_errors(is_alive);
1750   return result;
1751 }
1752 
1753 
1754 // The mirrors are scanned by shared_oops_do() which is
1755 // not called by oops_do().  In order to process oops in
1756 // a necessary order, shared_oops_do() is call by
1757 // Universe::oops_do().
1758 void SystemDictionary::oops_do(OopClosure* f) {
1759   // Adjust preloaded classes and system loader object
1760   f->do_oop(&_java_system_loader);
1761   preloaded_oops_do(f);
1762 
1763   lazily_loaded_oops_do(f);
1764 
1765   // Adjust dictionary
1766   dictionary()->oops_do(f);
1767 
1768   // Visit extra methods
1769   if (invoke_method_table() != NULL)
1770     invoke_method_table()->oops_do(f);
1771 
1772   // Partially loaded classes
1773   placeholders()->oops_do(f);
1774 
1775   // Adjust constraint table
1776   constraints()->oops_do(f);
1777 
1778   // Adjust resolution error table
1779   resolution_errors()->oops_do(f);
1780 }
1781 
1782 
1783 void SystemDictionary::preloaded_oops_do(OopClosure* f) {
1784   f->do_oop((oop*) &wk_klass_name_limits[0]);
1785   f->do_oop((oop*) &wk_klass_name_limits[1]);
1786 
1787   for (int k = (int)FIRST_WKID; k < (int)WKID_LIMIT; k++) {
1788     f->do_oop((oop*) &_well_known_klasses[k]);
1789   }
1790 
1791   {
1792     for (int i = 0; i < T_VOID+1; i++) {
1793       if (_box_klasses[i] != NULL) {
1794         assert(i >= T_BOOLEAN, "checking");
1795         f->do_oop((oop*) &_box_klasses[i]);
1796       }
1797     }
1798   }
1799 
1800   // The basic type mirrors would have already been processed in
1801   // Universe::oops_do(), via a call to shared_oops_do(), so should
1802   // not be processed again.
1803 
1804   f->do_oop((oop*) &_system_loader_lock_obj);
1805   FilteredFieldsMap::klasses_oops_do(f);
1806 }
1807 
1808 void SystemDictionary::lazily_loaded_oops_do(OopClosure* f) {
1809   f->do_oop((oop*) &_abstract_ownable_synchronizer_klass);
1810 }
1811 
1812 // Just the classes from defining class loaders
1813 // Don't iterate over placeholders
1814 void SystemDictionary::classes_do(void f(klassOop)) {
1815   dictionary()->classes_do(f);
1816 }
1817 
1818 // Added for initialize_itable_for_klass
1819 //   Just the classes from defining class loaders
1820 // Don't iterate over placeholders
1821 void SystemDictionary::classes_do(void f(klassOop, TRAPS), TRAPS) {
1822   dictionary()->classes_do(f, CHECK);
1823 }
1824 
1825 //   All classes, and their class loaders
1826 // Don't iterate over placeholders
1827 void SystemDictionary::classes_do(void f(klassOop, oop)) {
1828   dictionary()->classes_do(f);
1829 }
1830 
1831 //   All classes, and their class loaders
1832 //   (added for helpers that use HandleMarks and ResourceMarks)
1833 // Don't iterate over placeholders
1834 void SystemDictionary::classes_do(void f(klassOop, oop, TRAPS), TRAPS) {
1835   dictionary()->classes_do(f, CHECK);
1836 }
1837 
1838 void SystemDictionary::placeholders_do(void f(symbolOop, oop)) {
1839   placeholders()->entries_do(f);
1840 }
1841 
1842 void SystemDictionary::methods_do(void f(methodOop)) {
1843   dictionary()->methods_do(f);
1844   if (invoke_method_table() != NULL)
1845     invoke_method_table()->methods_do(f);
1846 }
1847 
1848 // ----------------------------------------------------------------------------
1849 // Lazily load klasses
1850 
1851 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
1852   assert(JDK_Version::is_gte_jdk16x_version(), "Must be JDK 1.6 or later");
1853 
1854   // if multiple threads calling this function, only one thread will load
1855   // the class.  The other threads will find the loaded version once the
1856   // class is loaded.
1857   klassOop aos = _abstract_ownable_synchronizer_klass;
1858   if (aos == NULL) {
1859     klassOop k = resolve_or_fail(vmSymbolHandles::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
1860     // Force a fence to prevent any read before the write completes
1861     OrderAccess::fence();
1862     _abstract_ownable_synchronizer_klass = k;
1863   }
1864 }
1865 
1866 // ----------------------------------------------------------------------------
1867 // Initialization
1868 
1869 void SystemDictionary::initialize(TRAPS) {
1870   // Allocate arrays
1871   assert(dictionary() == NULL,
1872          "SystemDictionary should only be initialized once");
1873   _dictionary = new Dictionary(_nof_buckets);
1874   _placeholders = new PlaceholderTable(_nof_buckets);
1875   _number_of_modifications = 0;
1876   _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
1877   _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
1878   // _invoke_method_table is allocated lazily in find_method_handle_invoke()
1879 
1880   // Allocate private object used as system class loader lock
1881   _system_loader_lock_obj = oopFactory::new_system_objArray(0, CHECK);
1882   // Initialize basic classes
1883   initialize_preloaded_classes(CHECK);
1884 }
1885 
1886 // Compact table of directions on the initialization of klasses:
1887 static const short wk_init_info[] = {
1888   #define WK_KLASS_INIT_INFO(name, symbol, option) \
1889     ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
1890           << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
1891       | (int)SystemDictionary::option ),
1892   WK_KLASSES_DO(WK_KLASS_INIT_INFO)
1893   #undef WK_KLASS_INIT_INFO
1894   0
1895 };
1896 
1897 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
1898   assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1899   int  info = wk_init_info[id - FIRST_WKID];
1900   int  sid  = (info >> CEIL_LG_OPTION_LIMIT);
1901   symbolHandle symbol = vmSymbolHandles::symbol_handle_at((vmSymbols::SID)sid);
1902   klassOop*    klassp = &_well_known_klasses[id];
1903   bool must_load = (init_opt < SystemDictionary::Opt);
1904   bool try_load  = true;
1905   if (init_opt == SystemDictionary::Opt_Kernel) {
1906 #ifndef KERNEL
1907     try_load = false;
1908 #endif //KERNEL
1909   }
1910   if ((*klassp) == NULL && try_load) {
1911     if (must_load) {
1912       (*klassp) = resolve_or_fail(symbol, true, CHECK_0); // load required class
1913     } else {
1914       (*klassp) = resolve_or_null(symbol,       CHECK_0); // load optional klass
1915     }
1916   }
1917   return ((*klassp) != NULL);
1918 }
1919 
1920 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
1921   assert((int)start_id <= (int)limit_id, "IDs are out of order!");
1922   for (int id = (int)start_id; id < (int)limit_id; id++) {
1923     assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1924     int info = wk_init_info[id - FIRST_WKID];
1925     int sid  = (info >> CEIL_LG_OPTION_LIMIT);
1926     int opt  = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
1927 
1928     initialize_wk_klass((WKID)id, opt, CHECK);
1929 
1930     // Update limits, so find_well_known_klass can be very fast:
1931     symbolOop s = vmSymbols::symbol_at((vmSymbols::SID)sid);
1932     if (wk_klass_name_limits[1] == NULL) {
1933       wk_klass_name_limits[0] = wk_klass_name_limits[1] = s;
1934     } else if (wk_klass_name_limits[1] < s) {
1935       wk_klass_name_limits[1] = s;
1936     } else if (wk_klass_name_limits[0] > s) {
1937       wk_klass_name_limits[0] = s;
1938     }
1939   }
1940 
1941   // move the starting value forward to the limit:
1942   start_id = limit_id;
1943 }
1944 
1945 
1946 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
1947   assert(WK_KLASS(object_klass) == NULL, "preloaded classes should only be initialized once");
1948   // Preload commonly used klasses
1949   WKID scan = FIRST_WKID;
1950   // first do Object, String, Class
1951   initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(class_klass), scan, CHECK);
1952 
1953   debug_only(instanceKlass::verify_class_klass_nonstatic_oop_maps(WK_KLASS(class_klass)));
1954 
1955   // Fixup mirrors for classes loaded before java.lang.Class.
1956   // These calls iterate over the objects currently in the perm gen
1957   // so calling them at this point is matters (not before when there
1958   // are fewer objects and not later after there are more objects
1959   // in the perm gen.
1960   Universe::initialize_basic_type_mirrors(CHECK);
1961   Universe::fixup_mirrors(CHECK);
1962 
1963   // do a bunch more:
1964   initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(reference_klass), scan, CHECK);
1965 
1966   // Preload ref klasses and set reference types
1967   instanceKlass::cast(WK_KLASS(reference_klass))->set_reference_type(REF_OTHER);
1968   instanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(reference_klass));
1969 
1970   initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(phantom_reference_klass), scan, CHECK);
1971   instanceKlass::cast(WK_KLASS(soft_reference_klass))->set_reference_type(REF_SOFT);
1972   instanceKlass::cast(WK_KLASS(weak_reference_klass))->set_reference_type(REF_WEAK);
1973   instanceKlass::cast(WK_KLASS(final_reference_klass))->set_reference_type(REF_FINAL);
1974   instanceKlass::cast(WK_KLASS(phantom_reference_klass))->set_reference_type(REF_PHANTOM);
1975 
1976   WKID meth_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
1977   WKID meth_group_end   = WK_KLASS_ENUM_NAME(WrongMethodTypeException_klass);
1978   initialize_wk_klasses_until(meth_group_start, scan, CHECK);
1979   if (EnableMethodHandles) {
1980     initialize_wk_klasses_through(meth_group_end, scan, CHECK);
1981   }
1982   if (_well_known_klasses[meth_group_start] == NULL) {
1983     // Skip the rest of the method handle classes, if MethodHandle is not loaded.
1984     scan = WKID(meth_group_end+1);
1985   }
1986   WKID indy_group_start = WK_KLASS_ENUM_NAME(Linkage_klass);
1987   WKID indy_group_end   = WK_KLASS_ENUM_NAME(InvokeDynamic_klass);
1988   initialize_wk_klasses_until(indy_group_start, scan, CHECK);
1989   if (EnableInvokeDynamic) {
1990     initialize_wk_klasses_through(indy_group_end, scan, CHECK);
1991   }
1992   if (_well_known_klasses[indy_group_start] == NULL) {
1993     // Skip the rest of the dynamic typing classes, if Linkage is not loaded.
1994     scan = WKID(indy_group_end+1);
1995   }
1996 
1997   initialize_wk_klasses_until(WKID_LIMIT, scan, CHECK);
1998 
1999   _box_klasses[T_BOOLEAN] = WK_KLASS(boolean_klass);
2000   _box_klasses[T_CHAR]    = WK_KLASS(char_klass);
2001   _box_klasses[T_FLOAT]   = WK_KLASS(float_klass);
2002   _box_klasses[T_DOUBLE]  = WK_KLASS(double_klass);
2003   _box_klasses[T_BYTE]    = WK_KLASS(byte_klass);
2004   _box_klasses[T_SHORT]   = WK_KLASS(short_klass);
2005   _box_klasses[T_INT]     = WK_KLASS(int_klass);
2006   _box_klasses[T_LONG]    = WK_KLASS(long_klass);
2007   //_box_klasses[T_OBJECT]  = WK_KLASS(object_klass);
2008   //_box_klasses[T_ARRAY]   = WK_KLASS(object_klass);
2009 
2010 #ifdef KERNEL
2011   if (sun_jkernel_DownloadManager_klass() == NULL) {
2012     warning("Cannot find sun/jkernel/DownloadManager");
2013   }
2014 #endif // KERNEL
2015 
2016   { // Compute whether we should use loadClass or loadClassInternal when loading classes.
2017     methodOop method = instanceKlass::cast(classloader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature());
2018     _has_loadClassInternal = (method != NULL);
2019   }
2020   { // Compute whether we should use checkPackageAccess or NOT
2021     methodOop method = instanceKlass::cast(classloader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
2022     _has_checkPackageAccess = (method != NULL);
2023   }
2024 }
2025 
2026 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2027 // If so, returns the basic type it holds.  If not, returns T_OBJECT.
2028 BasicType SystemDictionary::box_klass_type(klassOop k) {
2029   assert(k != NULL, "");
2030   for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2031     if (_box_klasses[i] == k)
2032       return (BasicType)i;
2033   }
2034   return T_OBJECT;
2035 }
2036 
2037 KlassHandle SystemDictionaryHandles::box_klass(BasicType t) {
2038   if (t >= T_BOOLEAN && t <= T_VOID)
2039     return KlassHandle(&SystemDictionary::_box_klasses[t], true);
2040   else
2041     return KlassHandle();
2042 }
2043 
2044 // Constraints on class loaders. The details of the algorithm can be
2045 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2046 // Virtual Machine" by Sheng Liang and Gilad Bracha.  The basic idea is
2047 // that the system dictionary needs to maintain a set of contraints that
2048 // must be satisfied by all classes in the dictionary.
2049 // if defining is true, then LinkageError if already in systemDictionary
2050 // if initiating loader, then ok if instanceKlass matches existing entry
2051 
2052 void SystemDictionary::check_constraints(int d_index, unsigned int d_hash,
2053                                          instanceKlassHandle k,
2054                                          Handle class_loader, bool defining,
2055                                          TRAPS) {
2056   const char *linkage_error = NULL;
2057   {
2058     symbolHandle name (THREAD, k->name());
2059     MutexLocker mu(SystemDictionary_lock, THREAD);
2060 
2061     klassOop check = find_class(d_index, d_hash, name, class_loader);
2062     if (check != (klassOop)NULL) {
2063       // if different instanceKlass - duplicate class definition,
2064       // else - ok, class loaded by a different thread in parallel,
2065       // we should only have found it if it was done loading and ok to use
2066       // system dictionary only holds instance classes, placeholders
2067       // also holds array classes
2068 
2069       assert(check->klass_part()->oop_is_instance(), "noninstance in systemdictionary");
2070       if ((defining == true) || (k() != check)) {
2071         linkage_error = "loader (instance of  %s): attempted  duplicate class "
2072           "definition for name: \"%s\"";
2073       } else {
2074         return;
2075       }
2076     }
2077 
2078 #ifdef ASSERT
2079     unsigned int p_hash = placeholders()->compute_hash(name, class_loader);
2080     int p_index = placeholders()->hash_to_index(p_hash);
2081     symbolOop ph_check = find_placeholder(p_index, p_hash, name, class_loader);
2082     assert(ph_check == NULL || ph_check == name(), "invalid symbol");
2083 #endif
2084 
2085     if (linkage_error == NULL) {
2086       if (constraints()->check_or_update(k, class_loader, name) == false) {
2087         linkage_error = "loader constraint violation: loader (instance of %s)"
2088           " previously initiated loading for a different type with name \"%s\"";
2089       }
2090     }
2091   }
2092 
2093   // Throw error now if needed (cannot throw while holding
2094   // SystemDictionary_lock because of rank ordering)
2095 
2096   if (linkage_error) {
2097     ResourceMark rm(THREAD);
2098     const char* class_loader_name = loader_name(class_loader());
2099     char* type_name = k->name()->as_C_string();
2100     size_t buflen = strlen(linkage_error) + strlen(class_loader_name) +
2101       strlen(type_name);
2102     char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
2103     jio_snprintf(buf, buflen, linkage_error, class_loader_name, type_name);
2104     THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
2105   }
2106 }
2107 
2108 
2109 // Update system dictionary - done after check_constraint and add_to_hierachy
2110 // have been called.
2111 void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash,
2112                                          int p_index, unsigned int p_hash,
2113                                          instanceKlassHandle k,
2114                                          Handle class_loader,
2115                                          TRAPS) {
2116   // Compile_lock prevents systemDictionary updates during compilations
2117   assert_locked_or_safepoint(Compile_lock);
2118   symbolHandle name (THREAD, k->name());
2119 
2120   {
2121   MutexLocker mu1(SystemDictionary_lock, THREAD);
2122 
2123   // See whether biased locking is enabled and if so set it for this
2124   // klass.
2125   // Note that this must be done past the last potential blocking
2126   // point / safepoint. We enable biased locking lazily using a
2127   // VM_Operation to iterate the SystemDictionary and installing the
2128   // biasable mark word into each instanceKlass's prototype header.
2129   // To avoid race conditions where we accidentally miss enabling the
2130   // optimization for one class in the process of being added to the
2131   // dictionary, we must not safepoint after the test of
2132   // BiasedLocking::enabled().
2133   if (UseBiasedLocking && BiasedLocking::enabled()) {
2134     // Set biased locking bit for all loaded classes; it will be
2135     // cleared if revocation occurs too often for this type
2136     // NOTE that we must only do this when the class is initally
2137     // defined, not each time it is referenced from a new class loader
2138     if (k->class_loader() == class_loader()) {
2139       k->set_prototype_header(markOopDesc::biased_locking_prototype());
2140     }
2141   }
2142 
2143   // Check for a placeholder. If there, remove it and make a
2144   // new system dictionary entry.
2145   placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD);
2146   klassOop sd_check = find_class(d_index, d_hash, name, class_loader);
2147   if (sd_check == NULL) {
2148     dictionary()->add_klass(name, class_loader, k);
2149     notice_modification();
2150   }
2151 #ifdef ASSERT
2152   sd_check = find_class(d_index, d_hash, name, class_loader);
2153   assert (sd_check != NULL, "should have entry in system dictionary");
2154 // Changed to allow PH to remain to complete class circularity checking
2155 // while only one thread can define a class at one time, multiple
2156 // classes can resolve the superclass for a class at one time,
2157 // and the placeholder is used to track that
2158 //  symbolOop ph_check = find_placeholder(p_index, p_hash, name, class_loader);
2159 //  assert (ph_check == NULL, "should not have a placeholder entry");
2160 #endif
2161     SystemDictionary_lock->notify_all();
2162   }
2163 }
2164 
2165 
2166 klassOop SystemDictionary::find_constrained_instance_or_array_klass(
2167                     symbolHandle class_name, Handle class_loader, TRAPS) {
2168 
2169   // First see if it has been loaded directly.
2170   // Force the protection domain to be null.  (This removes protection checks.)
2171   Handle no_protection_domain;
2172   klassOop klass = find_instance_or_array_klass(class_name, class_loader,
2173                                                 no_protection_domain, CHECK_NULL);
2174   if (klass != NULL)
2175     return klass;
2176 
2177   // Now look to see if it has been loaded elsewhere, and is subject to
2178   // a loader constraint that would require this loader to return the
2179   // klass that is already loaded.
2180   if (FieldType::is_array(class_name())) {
2181     // Array classes are hard because their klassOops are not kept in the
2182     // constraint table. The array klass may be constrained, but the elem class
2183     // may not be.
2184     jint dimension;
2185     symbolOop object_key;
2186     BasicType t = FieldType::get_array_info(class_name(), &dimension,
2187                                             &object_key, CHECK_(NULL));
2188     if (t != T_OBJECT) {
2189       klass = Universe::typeArrayKlassObj(t);
2190     } else {
2191       symbolHandle elem_name(THREAD, object_key);
2192       MutexLocker mu(SystemDictionary_lock, THREAD);
2193       klass = constraints()->find_constrained_elem_klass(class_name, elem_name, class_loader, THREAD);
2194     }
2195     if (klass != NULL) {
2196       klass = Klass::cast(klass)->array_klass_or_null(dimension);
2197     }
2198   } else {
2199     MutexLocker mu(SystemDictionary_lock, THREAD);
2200     // Non-array classes are easy: simply check the constraint table.
2201     klass = constraints()->find_constrained_klass(class_name, class_loader);
2202   }
2203 
2204   return klass;
2205 }
2206 
2207 
2208 bool SystemDictionary::add_loader_constraint(symbolHandle class_name,
2209                                              Handle class_loader1,
2210                                              Handle class_loader2,
2211                                              Thread* THREAD) {
2212   unsigned int d_hash1 = dictionary()->compute_hash(class_name, class_loader1);
2213   int d_index1 = dictionary()->hash_to_index(d_hash1);
2214 
2215   unsigned int d_hash2 = dictionary()->compute_hash(class_name, class_loader2);
2216   int d_index2 = dictionary()->hash_to_index(d_hash2);
2217 
2218   {
2219     MutexLocker mu_s(SystemDictionary_lock, THREAD);
2220 
2221     // Better never do a GC while we're holding these oops
2222     No_Safepoint_Verifier nosafepoint;
2223 
2224     klassOop klass1 = find_class(d_index1, d_hash1, class_name, class_loader1);
2225     klassOop klass2 = find_class(d_index2, d_hash2, class_name, class_loader2);
2226     return constraints()->add_entry(class_name, klass1, class_loader1,
2227                                     klass2, class_loader2);
2228   }
2229 }
2230 
2231 // Add entry to resolution error table to record the error when the first
2232 // attempt to resolve a reference to a class has failed.
2233 void SystemDictionary::add_resolution_error(constantPoolHandle pool, int which, symbolHandle error) {
2234   unsigned int hash = resolution_errors()->compute_hash(pool, which);
2235   int index = resolution_errors()->hash_to_index(hash);
2236   {
2237     MutexLocker ml(SystemDictionary_lock, Thread::current());
2238     resolution_errors()->add_entry(index, hash, pool, which, error);
2239   }
2240 }
2241 
2242 // Lookup resolution error table. Returns error if found, otherwise NULL.
2243 symbolOop SystemDictionary::find_resolution_error(constantPoolHandle pool, int which) {
2244   unsigned int hash = resolution_errors()->compute_hash(pool, which);
2245   int index = resolution_errors()->hash_to_index(hash);
2246   {
2247     MutexLocker ml(SystemDictionary_lock, Thread::current());
2248     ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2249     return (entry != NULL) ? entry->error() : (symbolOop)NULL;
2250   }
2251 }
2252 
2253 
2254 // Signature constraints ensure that callers and callees agree about
2255 // the meaning of type names in their signatures.  This routine is the
2256 // intake for constraints.  It collects them from several places:
2257 //
2258 //  * LinkResolver::resolve_method (if check_access is true) requires
2259 //    that the resolving class (the caller) and the defining class of
2260 //    the resolved method (the callee) agree on each type in the
2261 //    method's signature.
2262 //
2263 //  * LinkResolver::resolve_interface_method performs exactly the same
2264 //    checks.
2265 //
2266 //  * LinkResolver::resolve_field requires that the constant pool
2267 //    attempting to link to a field agree with the field's defining
2268 //    class about the type of the field signature.
2269 //
2270 //  * klassVtable::initialize_vtable requires that, when a class
2271 //    overrides a vtable entry allocated by a superclass, that the
2272 //    overriding method (i.e., the callee) agree with the superclass
2273 //    on each type in the method's signature.
2274 //
2275 //  * klassItable::initialize_itable requires that, when a class fills
2276 //    in its itables, for each non-abstract method installed in an
2277 //    itable, the method (i.e., the callee) agree with the interface
2278 //    on each type in the method's signature.
2279 //
2280 // All those methods have a boolean (check_access, checkconstraints)
2281 // which turns off the checks.  This is used from specialized contexts
2282 // such as bootstrapping, dumping, and debugging.
2283 //
2284 // No direct constraint is placed between the class and its
2285 // supertypes.  Constraints are only placed along linked relations
2286 // between callers and callees.  When a method overrides or implements
2287 // an abstract method in a supertype (superclass or interface), the
2288 // constraints are placed as if the supertype were the caller to the
2289 // overriding method.  (This works well, since callers to the
2290 // supertype have already established agreement between themselves and
2291 // the supertype.)  As a result of all this, a class can disagree with
2292 // its supertype about the meaning of a type name, as long as that
2293 // class neither calls a relevant method of the supertype, nor is
2294 // called (perhaps via an override) from the supertype.
2295 //
2296 //
2297 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2298 //
2299 // Make sure all class components (including arrays) in the given
2300 // signature will be resolved to the same class in both loaders.
2301 // Returns the name of the type that failed a loader constraint check, or
2302 // NULL if no constraint failed. The returned C string needs cleaning up
2303 // with a ResourceMark in the caller.  No exception except OOME is thrown.
2304 char* SystemDictionary::check_signature_loaders(symbolHandle signature,
2305                                                Handle loader1, Handle loader2,
2306                                                bool is_method, TRAPS)  {
2307   // Nothing to do if loaders are the same.
2308   if (loader1() == loader2()) {
2309     return NULL;
2310   }
2311 
2312   SignatureStream sig_strm(signature, is_method);
2313   while (!sig_strm.is_done()) {
2314     if (sig_strm.is_object()) {
2315       symbolOop s = sig_strm.as_symbol(CHECK_NULL);
2316       symbolHandle sig (THREAD, s);
2317       if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2318         return sig()->as_C_string();
2319       }
2320     }
2321     sig_strm.next();
2322   }
2323   return NULL;
2324 }
2325 
2326 
2327 methodOop SystemDictionary::find_method_handle_invoke(symbolHandle signature,
2328                                                       Handle class_loader,
2329                                                       Handle protection_domain,
2330                                                       TRAPS) {
2331   if (!EnableMethodHandles)  return NULL;
2332   assert(class_loader.is_null() && protection_domain.is_null(),
2333          "cannot load specialized versions of MethodHandle.invoke");
2334   if (invoke_method_table() == NULL) {
2335     // create this side table lazily
2336     _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
2337   }
2338   unsigned int hash  = invoke_method_table()->compute_hash(signature);
2339   int          index = invoke_method_table()->hash_to_index(hash);
2340   SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature);
2341   if (spe == NULL || spe->property_oop() == NULL) {
2342     // Must create lots of stuff here, but outside of the SystemDictionary lock.
2343     if (THREAD->is_Compiler_thread())
2344       return NULL;              // do not attempt from within compiler
2345     Handle mt = compute_method_handle_type(signature(),
2346                                            class_loader, protection_domain,
2347                                            CHECK_NULL);
2348     KlassHandle  mh_klass = SystemDictionaryHandles::MethodHandle_klass();
2349     methodHandle m = methodOopDesc::make_invoke_method(mh_klass, signature,
2350                                                        mt, CHECK_NULL);
2351     // Now grab the lock.  We might have to throw away the new method,
2352     // if a racing thread has managed to install one at the same time.
2353     {
2354       MutexLocker ml(SystemDictionary_lock, Thread::current());
2355       spe = invoke_method_table()->find_entry(index, hash, signature);
2356       if (spe == NULL)
2357         spe = invoke_method_table()->add_entry(index, hash, signature);
2358       if (spe->property_oop() == NULL)
2359         spe->set_property_oop(m());
2360     }
2361   }
2362   methodOop m = (methodOop) spe->property_oop();
2363   assert(m->is_method(), "");
2364   return m;
2365 }
2366 
2367 // Ask Java code to find or construct a java.dyn.MethodType for the given
2368 // signature, as interpreted relative to the given class loader.
2369 // Because of class loader constraints, all method handle usage must be
2370 // consistent with this loader.
2371 Handle SystemDictionary::compute_method_handle_type(symbolHandle signature,
2372                                                     Handle class_loader,
2373                                                     Handle protection_domain,
2374                                                     TRAPS) {
2375   Handle empty;
2376   int npts = ArgumentCount(signature()).size();
2377   objArrayHandle pts = oopFactory::new_objArray(SystemDictionary::class_klass(), npts, CHECK_(empty));
2378   int arg = 0;
2379   Handle rt;                            // the return type from the signature
2380   for (SignatureStream ss(signature()); !ss.is_done(); ss.next()) {
2381     oop mirror;
2382     if (!ss.is_object()) {
2383       mirror = Universe::java_mirror(ss.type());
2384     } else {
2385       symbolOop    name_oop = ss.as_symbol(CHECK_(empty));
2386       symbolHandle name(THREAD, name_oop);
2387       klassOop klass = resolve_or_fail(name,
2388                                        class_loader, protection_domain,
2389                                        true, CHECK_(empty));
2390       mirror = Klass::cast(klass)->java_mirror();
2391     }
2392     if (ss.at_return_type())
2393       rt = Handle(THREAD, mirror);
2394     else
2395       pts->obj_at_put(arg++, mirror);
2396   }
2397   assert(arg == npts, "");
2398 
2399   // call MethodType java.dyn.MethodType::makeImpl(Class rt, Class[] pts, false, true)
2400   bool varargs = false, trusted = true;
2401   JavaCallArguments args(Handle(THREAD, rt()));
2402   args.push_oop(pts());
2403   args.push_int(false);
2404   args.push_int(trusted);
2405   JavaValue result(T_OBJECT);
2406   JavaCalls::call_static(&result,
2407                          SystemDictionary::MethodType_klass(),
2408                          vmSymbols::makeImpl_name(), vmSymbols::makeImpl_signature(),
2409                          &args, CHECK_(empty));
2410   return Handle(THREAD, (oop) result.get_jobject());
2411 }
2412 
2413 
2414 // Ask Java code to find or construct a java.dyn.CallSite for the given
2415 // name and signature, as interpreted relative to the given class loader.
2416 Handle SystemDictionary::make_dynamic_call_site(KlassHandle caller,
2417                                                 int caller_method_idnum,
2418                                                 int caller_bci,
2419                                                 symbolHandle name,
2420                                                 methodHandle mh_invdyn,
2421                                                 TRAPS) {
2422   Handle empty;
2423   // call java.dyn.CallSite::makeSite(caller, name, mtype, cmid, cbci)
2424   oop name_str_oop = StringTable::intern(name(), CHECK_(empty)); // not a handle!
2425   JavaCallArguments args(Handle(THREAD, caller->java_mirror()));
2426   args.push_oop(name_str_oop);
2427   args.push_oop(mh_invdyn->method_handle_type());
2428   args.push_int(caller_method_idnum);
2429   args.push_int(caller_bci);
2430   JavaValue result(T_OBJECT);
2431   JavaCalls::call_static(&result,
2432                          SystemDictionary::CallSite_klass(),
2433                          vmSymbols::makeSite_name(), vmSymbols::makeSite_signature(),
2434                          &args, CHECK_(empty));
2435   oop call_site_oop = (oop) result.get_jobject();
2436   assert(call_site_oop->is_oop()
2437          /*&& java_dyn_CallSite::is_instance(call_site_oop)*/, "must be sane");
2438   java_dyn_CallSite::set_vmmethod(call_site_oop, mh_invdyn());
2439   if (TraceMethodHandles) {
2440 #ifndef PRODUCT
2441     tty->print_cr("Linked invokedynamic bci=%d site="INTPTR_FORMAT":", caller_bci, call_site_oop);
2442     call_site_oop->print();
2443     tty->cr();
2444 #endif //PRODUCT
2445   }
2446   return call_site_oop;
2447 }
2448 
2449 Handle SystemDictionary::find_bootstrap_method(KlassHandle caller,
2450                                                KlassHandle search_bootstrap_klass,
2451                                                TRAPS) {
2452   Handle empty;
2453   if (!caller->oop_is_instance())  return empty;
2454 
2455   instanceKlassHandle ik(THREAD, caller());
2456 
2457   oop boot_method_oop = ik->bootstrap_method();
2458   if (boot_method_oop != NULL) {
2459     if (TraceMethodHandles) {
2460       tty->print_cr("bootstrap method for "PTR_FORMAT" cached as "PTR_FORMAT":", ik(), boot_method_oop);
2461     }
2462     NOT_PRODUCT(if (!boot_method_oop->is_oop()) { tty->print_cr("*** boot MH of "PTR_FORMAT" = "PTR_FORMAT, ik(), boot_method_oop); ik()->print(); });
2463     assert(boot_method_oop->is_oop()
2464            && java_dyn_MethodHandle::is_instance(boot_method_oop), "must be sane");
2465     return Handle(THREAD, boot_method_oop);
2466   }
2467   boot_method_oop = NULL;  // GC safety
2468 
2469   // call java.dyn.Linkage::findBootstrapMethod(caller, sbk)
2470   JavaCallArguments args(Handle(THREAD, ik->java_mirror()));
2471   if (search_bootstrap_klass.is_null())
2472     args.push_oop(Handle());
2473   else
2474     args.push_oop(search_bootstrap_klass->java_mirror());
2475   JavaValue result(T_OBJECT);
2476   JavaCalls::call_static(&result,
2477                          SystemDictionary::Linkage_klass(),
2478                          vmSymbols::findBootstrapMethod_name(),
2479                          vmSymbols::findBootstrapMethod_signature(),
2480                          &args, CHECK_(empty));
2481   boot_method_oop = (oop) result.get_jobject();
2482 
2483   if (boot_method_oop != NULL) {
2484     if (TraceMethodHandles) {
2485 #ifndef PRODUCT
2486       tty->print_cr("--------");
2487       tty->print_cr("bootstrap method for "PTR_FORMAT" computed as "PTR_FORMAT":", ik(), boot_method_oop);
2488       ik()->print();
2489       boot_method_oop->print();
2490       tty->print_cr("========");
2491 #endif //PRODUCT
2492     }
2493     assert(boot_method_oop->is_oop()
2494            && java_dyn_MethodHandle::is_instance(boot_method_oop), "must be sane");
2495     // probably no race conditions, but let's be careful:
2496     if (Atomic::cmpxchg_ptr(boot_method_oop, ik->adr_bootstrap_method(), NULL) == NULL)
2497       ik->set_bootstrap_method(boot_method_oop);
2498     else
2499       boot_method_oop = ik->bootstrap_method();
2500   } else {
2501     if (TraceMethodHandles) {
2502 #ifndef PRODUCT
2503       tty->print_cr("--------");
2504       tty->print_cr("bootstrap method for "PTR_FORMAT" computed as NULL:", ik());
2505       ik()->print();
2506       tty->print_cr("========");
2507 #endif //PRODUCT
2508     }
2509     boot_method_oop = ik->bootstrap_method();
2510   }
2511 
2512   return Handle(THREAD, boot_method_oop);
2513 }
2514 
2515 // Since the identity hash code for symbols changes when the symbols are
2516 // moved from the regular perm gen (hash in the mark word) to the shared
2517 // spaces (hash is the address), the classes loaded into the dictionary
2518 // may be in the wrong buckets.
2519 
2520 void SystemDictionary::reorder_dictionary() {
2521   dictionary()->reorder_dictionary();
2522 }
2523 
2524 
2525 void SystemDictionary::copy_buckets(char** top, char* end) {
2526   dictionary()->copy_buckets(top, end);
2527 }
2528 
2529 
2530 void SystemDictionary::copy_table(char** top, char* end) {
2531   dictionary()->copy_table(top, end);
2532 }
2533 
2534 
2535 void SystemDictionary::reverse() {
2536   dictionary()->reverse();
2537 }
2538 
2539 int SystemDictionary::number_of_classes() {
2540   return dictionary()->number_of_entries();
2541 }
2542 
2543 
2544 // ----------------------------------------------------------------------------
2545 #ifndef PRODUCT
2546 
2547 void SystemDictionary::print() {
2548   dictionary()->print();
2549 
2550   // Placeholders
2551   GCMutexLocker mu(SystemDictionary_lock);
2552   placeholders()->print();
2553 
2554   // loader constraints - print under SD_lock
2555   constraints()->print();
2556 }
2557 
2558 #endif
2559 
2560 void SystemDictionary::verify() {
2561   guarantee(dictionary() != NULL, "Verify of system dictionary failed");
2562   guarantee(constraints() != NULL,
2563             "Verify of loader constraints failed");
2564   guarantee(dictionary()->number_of_entries() >= 0 &&
2565             placeholders()->number_of_entries() >= 0,
2566             "Verify of system dictionary failed");
2567 
2568   // Verify dictionary
2569   dictionary()->verify();
2570 
2571   GCMutexLocker mu(SystemDictionary_lock);
2572   placeholders()->verify();
2573 
2574   // Verify constraint table
2575   guarantee(constraints() != NULL, "Verify of loader constraints failed");
2576   constraints()->verify(dictionary());
2577 }
2578 
2579 
2580 void SystemDictionary::verify_obj_klass_present(Handle obj,
2581                                                 symbolHandle class_name,
2582                                                 Handle class_loader) {
2583   GCMutexLocker mu(SystemDictionary_lock);
2584   oop probe = find_class_or_placeholder(class_name, class_loader);
2585   if (probe == NULL) {
2586     probe = SystemDictionary::find_shared_class(class_name);
2587   }
2588   guarantee(probe != NULL &&
2589             (!probe->is_klass() || probe == obj()),
2590                      "Loaded klasses should be in SystemDictionary");
2591 }
2592 
2593 #ifndef PRODUCT
2594 
2595 // statistics code
2596 class ClassStatistics: AllStatic {
2597  private:
2598   static int nclasses;        // number of classes
2599   static int nmethods;        // number of methods
2600   static int nmethoddata;     // number of methodData
2601   static int class_size;      // size of class objects in words
2602   static int method_size;     // size of method objects in words
2603   static int debug_size;      // size of debug info in methods
2604   static int methoddata_size; // size of methodData objects in words
2605 
2606   static void do_class(klassOop k) {
2607     nclasses++;
2608     class_size += k->size();
2609     if (k->klass_part()->oop_is_instance()) {
2610       instanceKlass* ik = (instanceKlass*)k->klass_part();
2611       class_size += ik->methods()->size();
2612       class_size += ik->constants()->size();
2613       class_size += ik->local_interfaces()->size();
2614       class_size += ik->transitive_interfaces()->size();
2615       // We do not have to count implementors, since we only store one!
2616       class_size += ik->fields()->size();
2617     }
2618   }
2619 
2620   static void do_method(methodOop m) {
2621     nmethods++;
2622     method_size += m->size();
2623     // class loader uses same objArray for empty vectors, so don't count these
2624     if (m->exception_table()->length() != 0)   method_size += m->exception_table()->size();
2625     if (m->has_stackmap_table()) {
2626       method_size += m->stackmap_data()->size();
2627     }
2628 
2629     methodDataOop mdo = m->method_data();
2630     if (mdo != NULL) {
2631       nmethoddata++;
2632       methoddata_size += mdo->size();
2633     }
2634   }
2635 
2636  public:
2637   static void print() {
2638     SystemDictionary::classes_do(do_class);
2639     SystemDictionary::methods_do(do_method);
2640     tty->print_cr("Class statistics:");
2641     tty->print_cr("%d classes (%d bytes)", nclasses, class_size * oopSize);
2642     tty->print_cr("%d methods (%d bytes = %d base + %d debug info)", nmethods,
2643                   (method_size + debug_size) * oopSize, method_size * oopSize, debug_size * oopSize);
2644     tty->print_cr("%d methoddata (%d bytes)", nmethoddata, methoddata_size * oopSize);
2645   }
2646 };
2647 
2648 
2649 int ClassStatistics::nclasses        = 0;
2650 int ClassStatistics::nmethods        = 0;
2651 int ClassStatistics::nmethoddata     = 0;
2652 int ClassStatistics::class_size      = 0;
2653 int ClassStatistics::method_size     = 0;
2654 int ClassStatistics::debug_size      = 0;
2655 int ClassStatistics::methoddata_size = 0;
2656 
2657 void SystemDictionary::print_class_statistics() {
2658   ResourceMark rm;
2659   ClassStatistics::print();
2660 }
2661 
2662 
2663 class MethodStatistics: AllStatic {
2664  public:
2665   enum {
2666     max_parameter_size = 10
2667   };
2668  private:
2669 
2670   static int _number_of_methods;
2671   static int _number_of_final_methods;
2672   static int _number_of_static_methods;
2673   static int _number_of_native_methods;
2674   static int _number_of_synchronized_methods;
2675   static int _number_of_profiled_methods;
2676   static int _number_of_bytecodes;
2677   static int _parameter_size_profile[max_parameter_size];
2678   static int _bytecodes_profile[Bytecodes::number_of_java_codes];
2679 
2680   static void initialize() {
2681     _number_of_methods        = 0;
2682     _number_of_final_methods  = 0;
2683     _number_of_static_methods = 0;
2684     _number_of_native_methods = 0;
2685     _number_of_synchronized_methods = 0;
2686     _number_of_profiled_methods = 0;
2687     _number_of_bytecodes      = 0;
2688     for (int i = 0; i < max_parameter_size             ; i++) _parameter_size_profile[i] = 0;
2689     for (int j = 0; j < Bytecodes::number_of_java_codes; j++) _bytecodes_profile     [j] = 0;
2690   };
2691 
2692   static void do_method(methodOop m) {
2693     _number_of_methods++;
2694     // collect flag info
2695     if (m->is_final()       ) _number_of_final_methods++;
2696     if (m->is_static()      ) _number_of_static_methods++;
2697     if (m->is_native()      ) _number_of_native_methods++;
2698     if (m->is_synchronized()) _number_of_synchronized_methods++;
2699     if (m->method_data() != NULL) _number_of_profiled_methods++;
2700     // collect parameter size info (add one for receiver, if any)
2701     _parameter_size_profile[MIN2(m->size_of_parameters() + (m->is_static() ? 0 : 1), max_parameter_size - 1)]++;
2702     // collect bytecodes info
2703     {
2704       Thread *thread = Thread::current();
2705       HandleMark hm(thread);
2706       BytecodeStream s(methodHandle(thread, m));
2707       Bytecodes::Code c;
2708       while ((c = s.next()) >= 0) {
2709         _number_of_bytecodes++;
2710         _bytecodes_profile[c]++;
2711       }
2712     }
2713   }
2714 
2715  public:
2716   static void print() {
2717     initialize();
2718     SystemDictionary::methods_do(do_method);
2719     // generate output
2720     tty->cr();
2721     tty->print_cr("Method statistics (static):");
2722     // flag distribution
2723     tty->cr();
2724     tty->print_cr("%6d final        methods  %6.1f%%", _number_of_final_methods       , _number_of_final_methods        * 100.0F / _number_of_methods);
2725     tty->print_cr("%6d static       methods  %6.1f%%", _number_of_static_methods      , _number_of_static_methods       * 100.0F / _number_of_methods);
2726     tty->print_cr("%6d native       methods  %6.1f%%", _number_of_native_methods      , _number_of_native_methods       * 100.0F / _number_of_methods);
2727     tty->print_cr("%6d synchronized methods  %6.1f%%", _number_of_synchronized_methods, _number_of_synchronized_methods * 100.0F / _number_of_methods);
2728     tty->print_cr("%6d profiled     methods  %6.1f%%", _number_of_profiled_methods, _number_of_profiled_methods * 100.0F / _number_of_methods);
2729     // parameter size profile
2730     tty->cr();
2731     { int tot = 0;
2732       int avg = 0;
2733       for (int i = 0; i < max_parameter_size; i++) {
2734         int n = _parameter_size_profile[i];
2735         tot += n;
2736         avg += n*i;
2737         tty->print_cr("parameter size = %1d: %6d methods  %5.1f%%", i, n, n * 100.0F / _number_of_methods);
2738       }
2739       assert(tot == _number_of_methods, "should be the same");
2740       tty->print_cr("                    %6d methods  100.0%%", _number_of_methods);
2741       tty->print_cr("(average parameter size = %3.1f including receiver, if any)", (float)avg / _number_of_methods);
2742     }
2743     // bytecodes profile
2744     tty->cr();
2745     { int tot = 0;
2746       for (int i = 0; i < Bytecodes::number_of_java_codes; i++) {
2747         if (Bytecodes::is_defined(i)) {
2748           Bytecodes::Code c = Bytecodes::cast(i);
2749           int n = _bytecodes_profile[c];
2750           tot += n;
2751           tty->print_cr("%9d  %7.3f%%  %s", n, n * 100.0F / _number_of_bytecodes, Bytecodes::name(c));
2752         }
2753       }
2754       assert(tot == _number_of_bytecodes, "should be the same");
2755       tty->print_cr("%9d  100.000%%", _number_of_bytecodes);
2756     }
2757     tty->cr();
2758   }
2759 };
2760 
2761 int MethodStatistics::_number_of_methods;
2762 int MethodStatistics::_number_of_final_methods;
2763 int MethodStatistics::_number_of_static_methods;
2764 int MethodStatistics::_number_of_native_methods;
2765 int MethodStatistics::_number_of_synchronized_methods;
2766 int MethodStatistics::_number_of_profiled_methods;
2767 int MethodStatistics::_number_of_bytecodes;
2768 int MethodStatistics::_parameter_size_profile[MethodStatistics::max_parameter_size];
2769 int MethodStatistics::_bytecodes_profile[Bytecodes::number_of_java_codes];
2770 
2771 
2772 void SystemDictionary::print_method_statistics() {
2773   MethodStatistics::print();
2774 }
2775 
2776 #endif // PRODUCT
--- EOF ---