1 /*
   2  * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "classfile/classLoaderData.inline.hpp"
  27 #include "classfile/dictionary.hpp"
  28 #include "classfile/javaClasses.hpp"
  29 #include "classfile/loaderConstraints.hpp"
  30 #include "classfile/placeholders.hpp"
  31 #include "classfile/resolutionErrors.hpp"
  32 #include "classfile/stringTable.hpp"
  33 #include "classfile/systemDictionary.hpp"
  34 #include "classfile/vmSymbols.hpp"
  35 #include "compiler/compileBroker.hpp"
  36 #include "interpreter/bytecodeStream.hpp"
  37 #include "interpreter/interpreter.hpp"
  38 #include "interpreter/linkResolver.hpp"
  39 #include "memory/gcLocker.hpp"
  40 #include "memory/oopFactory.hpp"
  41 #include "oops/instanceKlass.hpp"
  42 #include "oops/instanceRefKlass.hpp"
  43 #include "oops/klass.inline.hpp"
  44 #include "oops/methodData.hpp"
  45 #include "oops/objArrayKlass.hpp"
  46 #include "oops/oop.inline.hpp"
  47 #include "oops/oop.inline2.hpp"
  48 #include "oops/typeArrayKlass.hpp"
  49 #include "prims/jvmtiEnvBase.hpp"
  50 #include "prims/methodHandles.hpp"
  51 #include "runtime/biasedLocking.hpp"
  52 #include "runtime/fieldType.hpp"
  53 #include "runtime/handles.inline.hpp"
  54 #include "runtime/java.hpp"
  55 #include "runtime/javaCalls.hpp"
  56 #include "runtime/mutexLocker.hpp"
  57 #include "runtime/orderAccess.inline.hpp"
  58 #include "runtime/signature.hpp"
  59 #include "services/classLoadingService.hpp"
  60 #include "services/threadService.hpp"
  61 #include "utilities/macros.hpp"
  62 #include "utilities/ticks.hpp"
  63 
  64 #if INCLUDE_TRACE
  65  #include "trace/tracing.hpp"
  66 #endif
  67 
  68 Dictionary*            SystemDictionary::_dictionary          = NULL;
  69 PlaceholderTable*      SystemDictionary::_placeholders        = NULL;
  70 Dictionary*            SystemDictionary::_shared_dictionary   = NULL;
  71 LoaderConstraintTable* SystemDictionary::_loader_constraints  = NULL;
  72 ResolutionErrorTable*  SystemDictionary::_resolution_errors   = NULL;
  73 SymbolPropertyTable*   SystemDictionary::_invoke_method_table = NULL;
  74 
  75 
  76 int         SystemDictionary::_number_of_modifications = 0;
  77 int         SystemDictionary::_sdgeneration               = 0;
  78 const int   SystemDictionary::_primelist[_prime_array_size] = {1009,2017,4049,5051,10103,
  79               20201,40423,99991};
  80 
  81 oop         SystemDictionary::_system_loader_lock_obj     =  NULL;
  82 
  83 Klass*      SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
  84                                                           =  { NULL /*, NULL...*/ };
  85 
  86 Klass*      SystemDictionary::_box_klasses[T_VOID+1]      =  { NULL /*, NULL...*/ };
  87 
  88 oop         SystemDictionary::_java_system_loader         =  NULL;
  89 
  90 bool        SystemDictionary::_has_loadClassInternal      =  false;
  91 bool        SystemDictionary::_has_checkPackageAccess     =  false;
  92 
  93 // lazily initialized klass variables
  94 Klass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
  95 
  96 
  97 // ----------------------------------------------------------------------------
  98 // Java-level SystemLoader
  99 
 100 oop SystemDictionary::java_system_loader() {
 101   return _java_system_loader;
 102 }
 103 
 104 void SystemDictionary::compute_java_system_loader(TRAPS) {
 105   KlassHandle system_klass(THREAD, WK_KLASS(ClassLoader_klass));
 106   JavaValue result(T_OBJECT);
 107   JavaCalls::call_static(&result,
 108                          KlassHandle(THREAD, WK_KLASS(ClassLoader_klass)),
 109                          vmSymbols::getSystemClassLoader_name(),
 110                          vmSymbols::void_classloader_signature(),
 111                          CHECK);
 112 
 113   _java_system_loader = (oop)result.get_jobject();
 114 }
 115 
 116 
 117 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, TRAPS) {
 118   if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
 119   return ClassLoaderDataGraph::find_or_create(class_loader, CHECK_NULL);
 120 }
 121 
 122 // ----------------------------------------------------------------------------
 123 // debugging
 124 
 125 #ifdef ASSERT
 126 
 127 // return true if class_name contains no '.' (internal format is '/')
 128 bool SystemDictionary::is_internal_format(Symbol* class_name) {
 129   if (class_name != NULL) {
 130     ResourceMark rm;
 131     char* name = class_name->as_C_string();
 132     return strchr(name, '.') == NULL;
 133   } else {
 134     return true;
 135   }
 136 }
 137 
 138 #endif
 139 
 140 // ----------------------------------------------------------------------------
 141 // Parallel class loading check
 142 
 143 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
 144   if (UnsyncloadClass || class_loader.is_null()) return true;
 145   if (AlwaysLockClassLoader) return false;
 146   return java_lang_ClassLoader::parallelCapable(class_loader());
 147 }
 148 // ----------------------------------------------------------------------------
 149 // ParallelDefineClass flag does not apply to bootclass loader
 150 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
 151    if (class_loader.is_null()) return false;
 152    if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
 153      return true;
 154    }
 155    return false;
 156 }
 157 
 158 /**
 159  * Returns true if the passed class loader is the extension class loader.
 160  */
 161 bool SystemDictionary::is_ext_class_loader(Handle class_loader) {
 162   if (class_loader.is_null()) {
 163     return false;
 164   }
 165   return (class_loader->klass()->name() == vmSymbols::sun_misc_Launcher_ExtClassLoader());
 166 }
 167 
 168 // ----------------------------------------------------------------------------
 169 // Resolving of classes
 170 
 171 // Forwards to resolve_or_null
 172 
 173 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
 174   Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
 175   if (HAS_PENDING_EXCEPTION || klass == NULL) {
 176     KlassHandle k_h(THREAD, klass);
 177     // can return a null klass
 178     klass = handle_resolution_exception(class_name, throw_error, k_h, THREAD);
 179   }
 180   return klass;
 181 }
 182 
 183 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name,
 184                                                      bool throw_error,
 185                                                      KlassHandle klass_h, TRAPS) {
 186   if (HAS_PENDING_EXCEPTION) {
 187     // If we have a pending exception we forward it to the caller, unless throw_error is true,
 188     // in which case we have to check whether the pending exception is a ClassNotFoundException,
 189     // and if so convert it to a NoClassDefFoundError
 190     // And chain the original ClassNotFoundException
 191     if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
 192       ResourceMark rm(THREAD);
 193       assert(klass_h() == NULL, "Should not have result with exception pending");
 194       Handle e(THREAD, PENDING_EXCEPTION);
 195       CLEAR_PENDING_EXCEPTION;
 196       THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
 197     } else {
 198       return NULL;
 199     }
 200   }
 201   // Class not found, throw appropriate error or exception depending on value of throw_error
 202   if (klass_h() == NULL) {
 203     ResourceMark rm(THREAD);
 204     if (throw_error) {
 205       THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
 206     } else {
 207       THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
 208     }
 209   }
 210   return (Klass*)klass_h();
 211 }
 212 
 213 
 214 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
 215                                            bool throw_error, TRAPS)
 216 {
 217   return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
 218 }
 219 
 220 
 221 // Forwards to resolve_instance_class_or_null
 222 
 223 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
 224   assert(!THREAD->is_Compiler_thread(),
 225          err_msg("can not load classes with compiler thread: class=%s, classloader=%s",
 226                  class_name->as_C_string(),
 227                  class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string()));
 228   if (FieldType::is_array(class_name)) {
 229     return resolve_array_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
 230   } else if (FieldType::is_obj(class_name)) {
 231     ResourceMark rm(THREAD);
 232     // Ignore wrapping L and ;.
 233     TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
 234                                    class_name->utf8_length() - 2, CHECK_NULL);
 235     return resolve_instance_class_or_null(name, class_loader, protection_domain, CHECK_NULL);
 236   } else {
 237     return resolve_instance_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
 238   }
 239 }
 240 
 241 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
 242   return resolve_or_null(class_name, Handle(), Handle(), THREAD);
 243 }
 244 
 245 // Forwards to resolve_instance_class_or_null
 246 
 247 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
 248                                                        Handle class_loader,
 249                                                        Handle protection_domain,
 250                                                        TRAPS) {
 251   assert(FieldType::is_array(class_name), "must be array");
 252   Klass* k = NULL;
 253   FieldArrayInfo fd;
 254   // dimension and object_key in FieldArrayInfo are assigned as a side-effect
 255   // of this call
 256   BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
 257   if (t == T_OBJECT) {
 258     // naked oop "k" is OK here -- we assign back into it
 259     k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
 260                                                          class_loader,
 261                                                          protection_domain,
 262                                                          CHECK_NULL);
 263     if (k != NULL) {
 264       k = k->array_klass(fd.dimension(), CHECK_NULL);
 265     }
 266   } else {
 267     k = Universe::typeArrayKlassObj(t);
 268     k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
 269   }
 270   return k;
 271 }
 272 
 273 
 274 // Must be called for any super-class or super-interface resolution
 275 // during class definition to allow class circularity checking
 276 // super-interface callers:
 277 //    parse_interfaces - for defineClass & jvmtiRedefineClasses
 278 // super-class callers:
 279 //   ClassFileParser - for defineClass & jvmtiRedefineClasses
 280 //   load_shared_class - while loading a class from shared archive
 281 //   resolve_instance_class_or_null:
 282 //     via: handle_parallel_super_load
 283 //      when resolving a class that has an existing placeholder with
 284 //      a saved superclass [i.e. a defineClass is currently in progress]
 285 //      if another thread is trying to resolve the class, it must do
 286 //      super-class checks on its own thread to catch class circularity
 287 // This last call is critical in class circularity checking for cases
 288 // where classloading is delegated to different threads and the
 289 // classloader lock is released.
 290 // Take the case: Base->Super->Base
 291 //   1. If thread T1 tries to do a defineClass of class Base
 292 //    resolve_super_or_fail creates placeholder: T1, Base (super Super)
 293 //   2. resolve_instance_class_or_null does not find SD or placeholder for Super
 294 //    so it tries to load Super
 295 //   3. If we load the class internally, or user classloader uses same thread
 296 //      loadClassFromxxx or defineClass via parseClassFile Super ...
 297 //      3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
 298 //      3.3 resolve_instance_class_or_null Base, finds placeholder for Base
 299 //      3.4 calls resolve_super_or_fail Base
 300 //      3.5 finds T1,Base -> throws class circularity
 301 //OR 4. If T2 tries to resolve Super via defineClass Super ...
 302 //      4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
 303 //      4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
 304 //      4.3 calls resolve_super_or_fail Super in parallel on own thread T2
 305 //      4.4 finds T2, Super -> throws class circularity
 306 // Must be called, even if superclass is null, since this is
 307 // where the placeholder entry is created which claims this
 308 // thread is loading this class/classloader.
 309 Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
 310                                                  Symbol* class_name,
 311                                                  Handle class_loader,
 312                                                  Handle protection_domain,
 313                                                  bool is_superclass,
 314                                                  TRAPS) {
 315   // Double-check, if child class is already loaded, just return super-class,interface
 316   // Don't add a placedholder if already loaded, i.e. already in system dictionary
 317   // Make sure there's a placeholder for the *child* before resolving.
 318   // Used as a claim that this thread is currently loading superclass/classloader
 319   // Used here for ClassCircularity checks and also for heap verification
 320   // (every InstanceKlass in the heap needs to be in the system dictionary
 321   // or have a placeholder).
 322   // Must check ClassCircularity before checking if super class is already loaded
 323   //
 324   // We might not already have a placeholder if this child_name was
 325   // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
 326   // the name of the class might not be known until the stream is actually
 327   // parsed.
 328   // Bugs 4643874, 4715493
 329   // compute_hash can have a safepoint
 330 
 331   ClassLoaderData* loader_data = class_loader_data(class_loader);
 332   unsigned int d_hash = dictionary()->compute_hash(child_name, loader_data);
 333   int d_index = dictionary()->hash_to_index(d_hash);
 334   unsigned int p_hash = placeholders()->compute_hash(child_name, loader_data);
 335   int p_index = placeholders()->hash_to_index(p_hash);
 336   // can't throw error holding a lock
 337   bool child_already_loaded = false;
 338   bool throw_circularity_error = false;
 339   {
 340     MutexLocker mu(SystemDictionary_lock, THREAD);
 341     Klass* childk = find_class(d_index, d_hash, child_name, loader_data);
 342     Klass* quicksuperk;
 343     // to support // loading: if child done loading, just return superclass
 344     // if class_name, & class_loader don't match:
 345     // if initial define, SD update will give LinkageError
 346     // if redefine: compare_class_versions will give HIERARCHY_CHANGED
 347     // so we don't throw an exception here.
 348     // see: nsk redefclass014 & java.lang.instrument Instrument032
 349     if ((childk != NULL ) && (is_superclass) &&
 350        ((quicksuperk = InstanceKlass::cast(childk)->super()) != NULL) &&
 351 
 352          ((quicksuperk->name() == class_name) &&
 353             (quicksuperk->class_loader()  == class_loader()))) {
 354            return quicksuperk;
 355     } else {
 356       PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
 357       if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
 358           throw_circularity_error = true;
 359       }
 360     }
 361     if (!throw_circularity_error) {
 362       PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
 363     }
 364   }
 365   if (throw_circularity_error) {
 366       ResourceMark rm(THREAD);
 367       THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
 368   }
 369 
 370 // java.lang.Object should have been found above
 371   assert(class_name != NULL, "null super class for resolving");
 372   // Resolve the super class or interface, check results on return
 373   Klass* superk = SystemDictionary::resolve_or_null(class_name,
 374                                                  class_loader,
 375                                                  protection_domain,
 376                                                  THREAD);
 377 
 378   KlassHandle superk_h(THREAD, superk);
 379 
 380   // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
 381   // It is no longer necessary to keep the placeholder table alive until update_dictionary
 382   // or error. GC used to walk the placeholder table as strong roots.
 383   // The instanceKlass is kept alive because the class loader is on the stack,
 384   // which keeps the loader_data alive, as well as all instanceKlasses in
 385   // the loader_data. parseClassFile adds the instanceKlass to loader_data.
 386   {
 387     MutexLocker mu(SystemDictionary_lock, THREAD);
 388     placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
 389     SystemDictionary_lock->notify_all();
 390   }
 391   if (HAS_PENDING_EXCEPTION || superk_h() == NULL) {
 392     // can null superk
 393     superk_h = KlassHandle(THREAD, handle_resolution_exception(class_name, true, superk_h, THREAD));
 394   }
 395 
 396   return superk_h();
 397 }
 398 
 399 void SystemDictionary::validate_protection_domain(instanceKlassHandle klass,
 400                                                   Handle class_loader,
 401                                                   Handle protection_domain,
 402                                                   TRAPS) {
 403   if(!has_checkPackageAccess()) return;
 404 
 405   // Now we have to call back to java to check if the initating class has access
 406   JavaValue result(T_VOID);
 407   if (TraceProtectionDomainVerification) {
 408     // Print out trace information
 409     tty->print_cr("Checking package access");
 410     tty->print(" - class loader:      "); class_loader()->print_value_on(tty);      tty->cr();
 411     tty->print(" - protection domain: "); protection_domain()->print_value_on(tty); tty->cr();
 412     tty->print(" - loading:           "); klass()->print_value_on(tty);             tty->cr();
 413   }
 414 
 415   KlassHandle system_loader(THREAD, SystemDictionary::ClassLoader_klass());
 416   JavaCalls::call_special(&result,
 417                          class_loader,
 418                          system_loader,
 419                          vmSymbols::checkPackageAccess_name(),
 420                          vmSymbols::class_protectiondomain_signature(),
 421                          Handle(THREAD, klass->java_mirror()),
 422                          protection_domain,
 423                          THREAD);
 424 
 425   if (TraceProtectionDomainVerification) {
 426     if (HAS_PENDING_EXCEPTION) {
 427       tty->print_cr(" -> DENIED !!!!!!!!!!!!!!!!!!!!!");
 428     } else {
 429      tty->print_cr(" -> granted");
 430     }
 431     tty->cr();
 432   }
 433 
 434   if (HAS_PENDING_EXCEPTION) return;
 435 
 436   // If no exception has been thrown, we have validated the protection domain
 437   // Insert the protection domain of the initiating class into the set.
 438   {
 439     // We recalculate the entry here -- we've called out to java since
 440     // the last time it was calculated.
 441     ClassLoaderData* loader_data = class_loader_data(class_loader);
 442 
 443     Symbol*  kn = klass->name();
 444     unsigned int d_hash = dictionary()->compute_hash(kn, loader_data);
 445     int d_index = dictionary()->hash_to_index(d_hash);
 446 
 447     MutexLocker mu(SystemDictionary_lock, THREAD);
 448     {
 449       // Note that we have an entry, and entries can be deleted only during GC,
 450       // so we cannot allow GC to occur while we're holding this entry.
 451 
 452       // We're using a No_Safepoint_Verifier to catch any place where we
 453       // might potentially do a GC at all.
 454       // Dictionary::do_unloading() asserts that classes in SD are only
 455       // unloaded at a safepoint. Anonymous classes are not in SD.
 456       No_Safepoint_Verifier nosafepoint;
 457       dictionary()->add_protection_domain(d_index, d_hash, klass, loader_data,
 458                                           protection_domain, THREAD);
 459     }
 460   }
 461 }
 462 
 463 // We only get here if this thread finds that another thread
 464 // has already claimed the placeholder token for the current operation,
 465 // but that other thread either never owned or gave up the
 466 // object lock
 467 // Waits on SystemDictionary_lock to indicate placeholder table updated
 468 // On return, caller must recheck placeholder table state
 469 //
 470 // We only get here if
 471 //  1) custom classLoader, i.e. not bootstrap classloader
 472 //  2) UnsyncloadClass not set
 473 //  3) custom classLoader has broken the class loader objectLock
 474 //     so another thread got here in parallel
 475 //
 476 // lockObject must be held.
 477 // Complicated dance due to lock ordering:
 478 // Must first release the classloader object lock to
 479 // allow initial definer to complete the class definition
 480 // and to avoid deadlock
 481 // Reclaim classloader lock object with same original recursion count
 482 // Must release SystemDictionary_lock after notify, since
 483 // class loader lock must be claimed before SystemDictionary_lock
 484 // to prevent deadlocks
 485 //
 486 // The notify allows applications that did an untimed wait() on
 487 // the classloader object lock to not hang.
 488 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
 489   assert_lock_strong(SystemDictionary_lock);
 490 
 491   bool calledholdinglock
 492       = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
 493   assert(calledholdinglock,"must hold lock for notify");
 494   assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
 495   ObjectSynchronizer::notifyall(lockObject, THREAD);
 496   intptr_t recursions =  ObjectSynchronizer::complete_exit(lockObject, THREAD);
 497   SystemDictionary_lock->wait();
 498   SystemDictionary_lock->unlock();
 499   ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
 500   SystemDictionary_lock->lock();
 501 }
 502 
 503 // If the class in is in the placeholder table, class loading is in progress
 504 // For cases where the application changes threads to load classes, it
 505 // is critical to ClassCircularity detection that we try loading
 506 // the superclass on the same thread internally, so we do parallel
 507 // super class loading here.
 508 // This also is critical in cases where the original thread gets stalled
 509 // even in non-circularity situations.
 510 // Note: must call resolve_super_or_fail even if null super -
 511 // to force placeholder entry creation for this class for circularity detection
 512 // Caller must check for pending exception
 513 // Returns non-null Klass* if other thread has completed load
 514 // and we are done,
 515 // If return null Klass* and no pending exception, the caller must load the class
 516 instanceKlassHandle SystemDictionary::handle_parallel_super_load(
 517     Symbol* name, Symbol* superclassname, Handle class_loader,
 518     Handle protection_domain, Handle lockObject, TRAPS) {
 519 
 520   instanceKlassHandle nh = instanceKlassHandle(); // null Handle
 521   ClassLoaderData* loader_data = class_loader_data(class_loader);
 522   unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
 523   int d_index = dictionary()->hash_to_index(d_hash);
 524   unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
 525   int p_index = placeholders()->hash_to_index(p_hash);
 526 
 527   // superk is not used, resolve_super called for circularity check only
 528   // This code is reached in two situations. One if this thread
 529   // is loading the same class twice (e.g. ClassCircularity, or
 530   // java.lang.instrument).
 531   // The second is if another thread started the resolve_super first
 532   // and has not yet finished.
 533   // In both cases the original caller will clean up the placeholder
 534   // entry on error.
 535   Klass* superk = SystemDictionary::resolve_super_or_fail(name,
 536                                                           superclassname,
 537                                                           class_loader,
 538                                                           protection_domain,
 539                                                           true,
 540                                                           CHECK_(nh));
 541 
 542   // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
 543   // Serial class loaders and bootstrap classloader do wait for superclass loads
 544  if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
 545     MutexLocker mu(SystemDictionary_lock, THREAD);
 546     // Check if classloading completed while we were loading superclass or waiting
 547     Klass* check = find_class(d_index, d_hash, name, loader_data);
 548     if (check != NULL) {
 549       // Klass is already loaded, so just return it
 550       return(instanceKlassHandle(THREAD, check));
 551     } else {
 552       return nh;
 553     }
 554   }
 555 
 556   // must loop to both handle other placeholder updates
 557   // and spurious notifications
 558   bool super_load_in_progress = true;
 559   PlaceholderEntry* placeholder;
 560   while (super_load_in_progress) {
 561     MutexLocker mu(SystemDictionary_lock, THREAD);
 562     // Check if classloading completed while we were loading superclass or waiting
 563     Klass* check = find_class(d_index, d_hash, name, loader_data);
 564     if (check != NULL) {
 565       // Klass is already loaded, so just return it
 566       return(instanceKlassHandle(THREAD, check));
 567     } else {
 568       placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
 569       if (placeholder && placeholder->super_load_in_progress() ){
 570         // Before UnsyncloadClass:
 571         // We only get here if the application has released the
 572         // classloader lock when another thread was in the middle of loading a
 573         // superclass/superinterface for this class, and now
 574         // this thread is also trying to load this class.
 575         // To minimize surprises, the first thread that started to
 576         // load a class should be the one to complete the loading
 577         // with the classfile it initially expected.
 578         // This logic has the current thread wait once it has done
 579         // all the superclass/superinterface loading it can, until
 580         // the original thread completes the class loading or fails
 581         // If it completes we will use the resulting InstanceKlass
 582         // which we will find below in the systemDictionary.
 583         // We also get here for parallel bootstrap classloader
 584         if (class_loader.is_null()) {
 585           SystemDictionary_lock->wait();
 586         } else {
 587           double_lock_wait(lockObject, THREAD);
 588         }
 589       } else {
 590         // If not in SD and not in PH, other thread's load must have failed
 591         super_load_in_progress = false;
 592       }
 593     }
 594   }
 595   return (nh);
 596 }
 597 
 598 
 599 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
 600                                                         Handle class_loader,
 601                                                         Handle protection_domain,
 602                                                         TRAPS) {
 603   assert(name != NULL && !FieldType::is_array(name) &&
 604          !FieldType::is_obj(name), "invalid class name");
 605 
 606   Ticks class_load_start_time = Ticks::now();
 607 
 608   // Fix for 4474172; see evaluation for more details
 609   class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
 610   ClassLoaderData *loader_data = register_loader(class_loader, CHECK_NULL);
 611 
 612   // Do lookup to see if class already exist and the protection domain
 613   // has the right access
 614   // This call uses find which checks protection domain already matches
 615   // All subsequent calls use find_class, and set has_loaded_class so that
 616   // before we return a result we call out to java to check for valid protection domain
 617   // to allow returning the Klass* and add it to the pd_set if it is valid
 618   unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
 619   int d_index = dictionary()->hash_to_index(d_hash);
 620   Klass* probe = dictionary()->find(d_index, d_hash, name, loader_data,
 621                                       protection_domain, THREAD);
 622   if (probe != NULL) return probe;
 623 
 624 
 625   // Non-bootstrap class loaders will call out to class loader and
 626   // define via jvm/jni_DefineClass which will acquire the
 627   // class loader object lock to protect against multiple threads
 628   // defining the class in parallel by accident.
 629   // This lock must be acquired here so the waiter will find
 630   // any successful result in the SystemDictionary and not attempt
 631   // the define
 632   // ParallelCapable Classloaders and the bootstrap classloader,
 633   // or all classloaders with UnsyncloadClass do not acquire lock here
 634   bool DoObjectLock = true;
 635   if (is_parallelCapable(class_loader)) {
 636     DoObjectLock = false;
 637   }
 638 
 639   unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
 640   int p_index = placeholders()->hash_to_index(p_hash);
 641 
 642   // Class is not in SystemDictionary so we have to do loading.
 643   // Make sure we are synchronized on the class loader before we proceed
 644   Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
 645   check_loader_lock_contention(lockObject, THREAD);
 646   ObjectLocker ol(lockObject, THREAD, DoObjectLock);
 647 
 648   // Check again (after locking) if class already exist in SystemDictionary
 649   bool class_has_been_loaded   = false;
 650   bool super_load_in_progress  = false;
 651   bool havesupername = false;
 652   instanceKlassHandle k;
 653   PlaceholderEntry* placeholder;
 654   Symbol* superclassname = NULL;
 655 
 656   {
 657     MutexLocker mu(SystemDictionary_lock, THREAD);
 658     Klass* check = find_class(d_index, d_hash, name, loader_data);
 659     if (check != NULL) {
 660       // Klass is already loaded, so just return it
 661       class_has_been_loaded = true;
 662       k = instanceKlassHandle(THREAD, check);
 663     } else {
 664       placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
 665       if (placeholder && placeholder->super_load_in_progress()) {
 666          super_load_in_progress = true;
 667          if (placeholder->havesupername() == true) {
 668            superclassname = placeholder->supername();
 669            havesupername = true;
 670          }
 671       }
 672     }
 673   }
 674 
 675   // If the class is in the placeholder table, class loading is in progress
 676   if (super_load_in_progress && havesupername==true) {
 677     k = SystemDictionary::handle_parallel_super_load(name, superclassname,
 678         class_loader, protection_domain, lockObject, THREAD);
 679     if (HAS_PENDING_EXCEPTION) {
 680       return NULL;
 681     }
 682     if (!k.is_null()) {
 683       class_has_been_loaded = true;
 684     }
 685   }
 686 
 687   bool throw_circularity_error = false;
 688   if (!class_has_been_loaded) {
 689     bool load_instance_added = false;
 690 
 691     // add placeholder entry to record loading instance class
 692     // Five cases:
 693     // All cases need to prevent modifying bootclasssearchpath
 694     // in parallel with a classload of same classname
 695     // Redefineclasses uses existence of the placeholder for the duration
 696     // of the class load to prevent concurrent redefinition of not completely
 697     // defined classes.
 698     // case 1. traditional classloaders that rely on the classloader object lock
 699     //   - no other need for LOAD_INSTANCE
 700     // case 2. traditional classloaders that break the classloader object lock
 701     //    as a deadlock workaround. Detection of this case requires that
 702     //    this check is done while holding the classloader object lock,
 703     //    and that lock is still held when calling classloader's loadClass.
 704     //    For these classloaders, we ensure that the first requestor
 705     //    completes the load and other requestors wait for completion.
 706     // case 3. UnsyncloadClass - don't use objectLocker
 707     //    With this flag, we allow parallel classloading of a
 708     //    class/classloader pair
 709     // case4. Bootstrap classloader - don't own objectLocker
 710     //    This classloader supports parallelism at the classloader level,
 711     //    but only allows a single load of a class/classloader pair.
 712     //    No performance benefit and no deadlock issues.
 713     // case 5. parallelCapable user level classloaders - without objectLocker
 714     //    Allow parallel classloading of a class/classloader pair
 715 
 716     {
 717       MutexLocker mu(SystemDictionary_lock, THREAD);
 718       if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
 719         PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
 720         if (oldprobe) {
 721           // only need check_seen_thread once, not on each loop
 722           // 6341374 java/lang/Instrument with -Xcomp
 723           if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
 724             throw_circularity_error = true;
 725           } else {
 726             // case 1: traditional: should never see load_in_progress.
 727             while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
 728 
 729               // case 4: bootstrap classloader: prevent futile classloading,
 730               // wait on first requestor
 731               if (class_loader.is_null()) {
 732                 SystemDictionary_lock->wait();
 733               } else {
 734               // case 2: traditional with broken classloader lock. wait on first
 735               // requestor.
 736                 double_lock_wait(lockObject, THREAD);
 737               }
 738               // Check if classloading completed while we were waiting
 739               Klass* check = find_class(d_index, d_hash, name, loader_data);
 740               if (check != NULL) {
 741                 // Klass is already loaded, so just return it
 742                 k = instanceKlassHandle(THREAD, check);
 743                 class_has_been_loaded = true;
 744               }
 745               // check if other thread failed to load and cleaned up
 746               oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
 747             }
 748           }
 749         }
 750       }
 751       // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
 752       // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try
 753       // LOAD_INSTANCE in parallel
 754 
 755       if (!throw_circularity_error && !class_has_been_loaded) {
 756         PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
 757         load_instance_added = true;
 758         // For class loaders that do not acquire the classloader object lock,
 759         // if they did not catch another thread holding LOAD_INSTANCE,
 760         // need a check analogous to the acquire ObjectLocker/find_class
 761         // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
 762         // one final check if the load has already completed
 763         // class loaders holding the ObjectLock shouldn't find the class here
 764         Klass* check = find_class(d_index, d_hash, name, loader_data);
 765         if (check != NULL) {
 766         // Klass is already loaded, so return it after checking/adding protection domain
 767           k = instanceKlassHandle(THREAD, check);
 768           class_has_been_loaded = true;
 769         }
 770       }
 771     }
 772 
 773     // must throw error outside of owning lock
 774     if (throw_circularity_error) {
 775       assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
 776       ResourceMark rm(THREAD);
 777       THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
 778     }
 779 
 780     if (!class_has_been_loaded) {
 781 
 782       // Do actual loading
 783       k = load_instance_class(name, class_loader, THREAD);
 784 
 785       // For UnsyncloadClass only
 786       // If they got a linkageError, check if a parallel class load succeeded.
 787       // If it did, then for bytecode resolution the specification requires
 788       // that we return the same result we did for the other thread, i.e. the
 789       // successfully loaded InstanceKlass
 790       // Should not get here for classloaders that support parallelism
 791       // with the new cleaner mechanism, even with AllowParallelDefineClass
 792       // Bootstrap goes through here to allow for an extra guarantee check
 793       if (UnsyncloadClass || (class_loader.is_null())) {
 794         if (k.is_null() && HAS_PENDING_EXCEPTION
 795           && PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass())) {
 796           MutexLocker mu(SystemDictionary_lock, THREAD);
 797           Klass* check = find_class(d_index, d_hash, name, loader_data);
 798           if (check != NULL) {
 799             // Klass is already loaded, so just use it
 800             k = instanceKlassHandle(THREAD, check);
 801             CLEAR_PENDING_EXCEPTION;
 802             guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?");
 803           }
 804         }
 805       }
 806 
 807       // If everything was OK (no exceptions, no null return value), and
 808       // class_loader is NOT the defining loader, do a little more bookkeeping.
 809       if (!HAS_PENDING_EXCEPTION && !k.is_null() &&
 810         k->class_loader() != class_loader()) {
 811 
 812         check_constraints(d_index, d_hash, k, class_loader, false, THREAD);
 813 
 814         // Need to check for a PENDING_EXCEPTION again; check_constraints
 815         // can throw and doesn't use the CHECK macro.
 816         if (!HAS_PENDING_EXCEPTION) {
 817           { // Grabbing the Compile_lock prevents systemDictionary updates
 818             // during compilations.
 819             MutexLocker mu(Compile_lock, THREAD);
 820             update_dictionary(d_index, d_hash, p_index, p_hash,
 821                               k, class_loader, THREAD);
 822           }
 823 
 824           if (JvmtiExport::should_post_class_load()) {
 825             Thread *thread = THREAD;
 826             assert(thread->is_Java_thread(), "thread->is_Java_thread()");
 827             JvmtiExport::post_class_load((JavaThread *) thread, k());
 828           }
 829         }
 830       }
 831     } // load_instance_class loop
 832 
 833     if (load_instance_added == true) {
 834       // clean up placeholder entries for LOAD_INSTANCE success or error
 835       // This brackets the SystemDictionary updates for both defining
 836       // and initiating loaders
 837       MutexLocker mu(SystemDictionary_lock, THREAD);
 838       placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
 839       SystemDictionary_lock->notify_all();
 840     }
 841   }
 842 
 843   if (HAS_PENDING_EXCEPTION || k.is_null()) {
 844     return NULL;
 845   }
 846 
 847   post_class_load_event(class_load_start_time, k, class_loader);
 848 
 849 #ifdef ASSERT
 850   {
 851     ClassLoaderData* loader_data = k->class_loader_data();
 852     MutexLocker mu(SystemDictionary_lock, THREAD);
 853     Klass* kk = find_class(name, loader_data);
 854     assert(kk == k(), "should be present in dictionary");
 855   }
 856 #endif
 857 
 858   // return if the protection domain in NULL
 859   if (protection_domain() == NULL) return k();
 860 
 861   // Check the protection domain has the right access
 862   {
 863     MutexLocker mu(SystemDictionary_lock, THREAD);
 864     // Note that we have an entry, and entries can be deleted only during GC,
 865     // so we cannot allow GC to occur while we're holding this entry.
 866     // We're using a No_Safepoint_Verifier to catch any place where we
 867     // might potentially do a GC at all.
 868     // Dictionary::do_unloading() asserts that classes in SD are only
 869     // unloaded at a safepoint. Anonymous classes are not in SD.
 870     No_Safepoint_Verifier nosafepoint;
 871     if (dictionary()->is_valid_protection_domain(d_index, d_hash, name,
 872                                                  loader_data,
 873                                                  protection_domain)) {
 874       return k();
 875     }
 876   }
 877 
 878   // Verify protection domain. If it fails an exception is thrown
 879   validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
 880 
 881   return k();
 882 }
 883 
 884 
 885 // This routine does not lock the system dictionary.
 886 //
 887 // Since readers don't hold a lock, we must make sure that system
 888 // dictionary entries are only removed at a safepoint (when only one
 889 // thread is running), and are added to in a safe way (all links must
 890 // be updated in an MT-safe manner).
 891 //
 892 // Callers should be aware that an entry could be added just after
 893 // _dictionary->bucket(index) is read here, so the caller will not see
 894 // the new entry.
 895 
 896 Klass* SystemDictionary::find(Symbol* class_name,
 897                               Handle class_loader,
 898                               Handle protection_domain,
 899                               TRAPS) {
 900 
 901   // The result of this call should be consistent with the result
 902   // of the call to resolve_instance_class_or_null().
 903   // See evaluation 6790209 and 4474172 for more details.
 904   class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
 905   ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
 906 
 907   if (loader_data == NULL) {
 908     // If the ClassLoaderData has not been setup,
 909     // then the class loader has no entries in the dictionary.
 910     return NULL;
 911   }
 912 
 913   unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
 914   int d_index = dictionary()->hash_to_index(d_hash);
 915 
 916   {
 917     // Note that we have an entry, and entries can be deleted only during GC,
 918     // so we cannot allow GC to occur while we're holding this entry.
 919     // We're using a No_Safepoint_Verifier to catch any place where we
 920     // might potentially do a GC at all.
 921     // Dictionary::do_unloading() asserts that classes in SD are only
 922     // unloaded at a safepoint. Anonymous classes are not in SD.
 923     No_Safepoint_Verifier nosafepoint;
 924     return dictionary()->find(d_index, d_hash, class_name, loader_data,
 925                               protection_domain, THREAD);
 926   }
 927 }
 928 
 929 
 930 // Look for a loaded instance or array klass by name.  Do not do any loading.
 931 // return NULL in case of error.
 932 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
 933                                                       Handle class_loader,
 934                                                       Handle protection_domain,
 935                                                       TRAPS) {
 936   Klass* k = NULL;
 937   assert(class_name != NULL, "class name must be non NULL");
 938 
 939   if (FieldType::is_array(class_name)) {
 940     // The name refers to an array.  Parse the name.
 941     // dimension and object_key in FieldArrayInfo are assigned as a
 942     // side-effect of this call
 943     FieldArrayInfo fd;
 944     BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
 945     if (t != T_OBJECT) {
 946       k = Universe::typeArrayKlassObj(t);
 947     } else {
 948       k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
 949     }
 950     if (k != NULL) {
 951       k = k->array_klass_or_null(fd.dimension());
 952     }
 953   } else {
 954     k = find(class_name, class_loader, protection_domain, THREAD);
 955   }
 956   return k;
 957 }
 958 
 959 // Note: this method is much like resolve_from_stream, but
 960 // updates no supplemental data structures.
 961 // TODO consolidate the two methods with a helper routine?
 962 Klass* SystemDictionary::parse_stream(Symbol* class_name,
 963                                       Handle class_loader,
 964                                       Handle protection_domain,
 965                                       ClassFileStream* st,
 966                                       KlassHandle host_klass,
 967                                       GrowableArray<Handle>* cp_patches,
 968                                       TRAPS) {
 969   TempNewSymbol parsed_name = NULL;
 970 
 971   Ticks class_load_start_time = Ticks::now();
 972 
 973   ClassLoaderData* loader_data;
 974   if (host_klass.not_null()) {
 975     // Create a new CLD for anonymous class, that uses the same class loader
 976     // as the host_klass
 977     guarantee(host_klass->class_loader() == class_loader(), "should be the same");
 978     loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader(), CHECK_NULL);
 979     loader_data->record_dependency(host_klass(), CHECK_NULL);
 980   } else {
 981     loader_data = ClassLoaderData::class_loader_data(class_loader());
 982   }
 983 
 984   // Parse the stream. Note that we do this even though this klass might
 985   // already be present in the SystemDictionary, otherwise we would not
 986   // throw potential ClassFormatErrors.
 987   //
 988   // Note: "name" is updated.
 989 
 990   instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
 991                                                              loader_data,
 992                                                              protection_domain,
 993                                                              host_klass,
 994                                                              cp_patches,
 995                                                              parsed_name,
 996                                                              true,
 997                                                              THREAD);
 998 
 999 
1000   if (host_klass.not_null() && k.not_null()) {
1001     // If it's anonymous, initialize it now, since nobody else will.
1002 
1003     {
1004       MutexLocker mu_r(Compile_lock, THREAD);
1005 
1006       // Add to class hierarchy, initialize vtables, and do possible
1007       // deoptimizations.
1008       add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1009 
1010       // But, do not add to system dictionary.
1011 
1012       // compiled code dependencies need to be validated anyway
1013       notice_modification();
1014     }
1015 
1016     // Rewrite and patch constant pool here.
1017     k->link_class(CHECK_NULL);
1018     if (cp_patches != NULL) {
1019       k->constants()->patch_resolved_references(cp_patches);
1020     }
1021     k->eager_initialize(CHECK_NULL);
1022 
1023     // notify jvmti
1024     if (JvmtiExport::should_post_class_load()) {
1025         assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1026         JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1027     }
1028 
1029     post_class_load_event(class_load_start_time, k, class_loader);
1030   }
1031   assert(host_klass.not_null() || cp_patches == NULL,
1032          "cp_patches only found with host_klass");
1033 
1034   return k();
1035 }
1036 
1037 // Add a klass to the system from a stream (called by jni_DefineClass and
1038 // JVM_DefineClass).
1039 // Note: class_name can be NULL. In that case we do not know the name of
1040 // the class until we have parsed the stream.
1041 
1042 Klass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1043                                              Handle class_loader,
1044                                              Handle protection_domain,
1045                                              ClassFileStream* st,
1046                                              bool verify,
1047                                              TRAPS) {
1048 
1049   // Classloaders that support parallelism, e.g. bootstrap classloader,
1050   // or all classloaders with UnsyncloadClass do not acquire lock here
1051   bool DoObjectLock = true;
1052   if (is_parallelCapable(class_loader)) {
1053     DoObjectLock = false;
1054   }
1055 
1056   ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL);
1057 
1058   // Make sure we are synchronized on the class loader before we proceed
1059   Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1060   check_loader_lock_contention(lockObject, THREAD);
1061   ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1062 
1063   TempNewSymbol parsed_name = NULL;
1064 
1065   // Parse the stream. Note that we do this even though this klass might
1066   // already be present in the SystemDictionary, otherwise we would not
1067   // throw potential ClassFormatErrors.
1068   //
1069   // Note: "name" is updated.
1070 
1071   instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
1072                                                              loader_data,
1073                                                              protection_domain,
1074                                                              parsed_name,
1075                                                              verify,
1076                                                              THREAD);
1077 
1078   const char* pkg = "java/";
1079   if (!HAS_PENDING_EXCEPTION &&
1080       !class_loader.is_null() &&
1081       parsed_name != NULL &&
1082       !strncmp((const char*)parsed_name->bytes(), pkg, strlen(pkg))) {
1083     // It is illegal to define classes in the "java." package from
1084     // JVM_DefineClass or jni_DefineClass unless you're the bootclassloader
1085     ResourceMark rm(THREAD);
1086     char* name = parsed_name->as_C_string();
1087     char* index = strrchr(name, '/');
1088     *index = '\0'; // chop to just the package name
1089     while ((index = strchr(name, '/')) != NULL) {
1090       *index = '.'; // replace '/' with '.' in package name
1091     }
1092     const char* fmt = "Prohibited package name: %s";
1093     size_t len = strlen(fmt) + strlen(name);
1094     char* message = NEW_RESOURCE_ARRAY(char, len);
1095     jio_snprintf(message, len, fmt, name);
1096     Exceptions::_throw_msg(THREAD_AND_LOCATION,
1097       vmSymbols::java_lang_SecurityException(), message);
1098   }
1099 
1100   if (!HAS_PENDING_EXCEPTION) {
1101     assert(parsed_name != NULL, "Sanity");
1102     assert(class_name == NULL || class_name == parsed_name, "name mismatch");
1103     // Verification prevents us from creating names with dots in them, this
1104     // asserts that that's the case.
1105     assert(is_internal_format(parsed_name),
1106            "external class name format used internally");
1107 
1108     // Add class just loaded
1109     // If a class loader supports parallel classloading handle parallel define requests
1110     // find_or_define_instance_class may return a different InstanceKlass
1111     if (is_parallelCapable(class_loader)) {
1112       k = find_or_define_instance_class(class_name, class_loader, k, THREAD);
1113     } else {
1114       define_instance_class(k, THREAD);
1115     }
1116   }
1117 
1118   // Make sure we have an entry in the SystemDictionary on success
1119   debug_only( {
1120     if (!HAS_PENDING_EXCEPTION) {
1121       assert(parsed_name != NULL, "parsed_name is still null?");
1122       Symbol*  h_name    = k->name();
1123       ClassLoaderData *defining_loader_data = k->class_loader_data();
1124 
1125       MutexLocker mu(SystemDictionary_lock, THREAD);
1126 
1127       Klass* check = find_class(parsed_name, loader_data);
1128       assert(check == k(), "should be present in the dictionary");
1129 
1130       Klass* check2 = find_class(h_name, defining_loader_data);
1131       assert(check == check2, "name inconsistancy in SystemDictionary");
1132     }
1133   } );
1134 
1135   return k();
1136 }
1137 
1138 
1139 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1140                                              int number_of_entries) {
1141   assert(length == _nof_buckets * sizeof(HashtableBucket<mtClass>),
1142          "bad shared dictionary size.");
1143   _shared_dictionary = new Dictionary(_nof_buckets, t, number_of_entries);
1144 }
1145 
1146 
1147 // If there is a shared dictionary, then find the entry for the
1148 // given shared system class, if any.
1149 
1150 Klass* SystemDictionary::find_shared_class(Symbol* class_name) {
1151   if (shared_dictionary() != NULL) {
1152     unsigned int d_hash = shared_dictionary()->compute_hash(class_name, NULL);
1153     int d_index = shared_dictionary()->hash_to_index(d_hash);
1154 
1155     return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1156   } else {
1157     return NULL;
1158   }
1159 }
1160 
1161 
1162 // Load a class from the shared spaces (found through the shared system
1163 // dictionary).  Force the superclass and all interfaces to be loaded.
1164 // Update the class definition to include sibling classes and no
1165 // subclasses (yet).  [Classes in the shared space are not part of the
1166 // object hierarchy until loaded.]
1167 
1168 instanceKlassHandle SystemDictionary::load_shared_class(
1169                  Symbol* class_name, Handle class_loader, TRAPS) {
1170   instanceKlassHandle ik (THREAD, find_shared_class(class_name));
1171   return load_shared_class(ik, class_loader, THREAD);
1172 }
1173 
1174 instanceKlassHandle SystemDictionary::load_shared_class(
1175                  instanceKlassHandle ik, Handle class_loader, TRAPS) {
1176   assert(class_loader.is_null(), "non-null classloader for shared class?");
1177   if (ik.not_null()) {
1178     instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1179     Symbol*  class_name = ik->name();
1180 
1181     // Found the class, now load the superclass and interfaces.  If they
1182     // are shared, add them to the main system dictionary and reset
1183     // their hierarchy references (supers, subs, and interfaces).
1184 
1185     if (ik->super() != NULL) {
1186       Symbol*  cn = ik->super()->name();
1187       resolve_super_or_fail(class_name, cn,
1188                             class_loader, Handle(), true, CHECK_(nh));
1189     }
1190 
1191     Array<Klass*>* interfaces = ik->local_interfaces();
1192     int num_interfaces = interfaces->length();
1193     for (int index = 0; index < num_interfaces; index++) {
1194       Klass* k = interfaces->at(index);
1195 
1196       // Note: can not use InstanceKlass::cast here because
1197       // interfaces' InstanceKlass's C++ vtbls haven't been
1198       // reinitialized yet (they will be once the interface classes
1199       // are loaded)
1200       Symbol*  name  = k->name();
1201       resolve_super_or_fail(class_name, name, class_loader, Handle(), false, CHECK_(nh));
1202     }
1203 
1204     // Adjust methods to recover missing data.  They need addresses for
1205     // interpreter entry points and their default native method address
1206     // must be reset.
1207 
1208     // Updating methods must be done under a lock so multiple
1209     // threads don't update these in parallel
1210     // Shared classes are all currently loaded by the bootstrap
1211     // classloader, so this will never cause a deadlock on
1212     // a custom class loader lock.
1213 
1214     {
1215       Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1216       check_loader_lock_contention(lockObject, THREAD);
1217       ObjectLocker ol(lockObject, THREAD, true);
1218       ik->restore_unshareable_info(CHECK_(nh));
1219     }
1220 
1221     if (TraceClassLoading) {
1222       ResourceMark rm;
1223       tty->print("[Loaded %s", ik->external_name());
1224       tty->print(" from shared objects file");
1225       tty->print_cr("]");
1226     }
1227     // notify a class loaded from shared object
1228     ClassLoadingService::notify_class_loaded(InstanceKlass::cast(ik()),
1229                                              true /* shared class */);
1230   }
1231   return ik;
1232 }
1233 
1234 
1235 instanceKlassHandle SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1236   instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1237   if (class_loader.is_null()) {
1238 
1239     // Search the shared system dictionary for classes preloaded into the
1240     // shared spaces.
1241     instanceKlassHandle k;
1242     {
1243       PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1244       k = load_shared_class(class_name, class_loader, THREAD);
1245     }
1246 
1247     if (k.is_null()) {
1248       // Use VM class loader
1249       PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1250       k = ClassLoader::load_classfile(class_name, CHECK_(nh));
1251     }
1252 
1253     // find_or_define_instance_class may return a different InstanceKlass
1254     if (!k.is_null()) {
1255       k = find_or_define_instance_class(class_name, class_loader, k, CHECK_(nh));
1256     }
1257     return k;
1258   } else {
1259     // Use user specified class loader to load class. Call loadClass operation on class_loader.
1260     ResourceMark rm(THREAD);
1261 
1262     assert(THREAD->is_Java_thread(), "must be a JavaThread");
1263     JavaThread* jt = (JavaThread*) THREAD;
1264 
1265     PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1266                                ClassLoader::perf_app_classload_selftime(),
1267                                ClassLoader::perf_app_classload_count(),
1268                                jt->get_thread_stat()->perf_recursion_counts_addr(),
1269                                jt->get_thread_stat()->perf_timers_addr(),
1270                                PerfClassTraceTime::CLASS_LOAD);
1271 
1272     Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nh));
1273     // Translate to external class name format, i.e., convert '/' chars to '.'
1274     Handle string = java_lang_String::externalize_classname(s, CHECK_(nh));
1275 
1276     JavaValue result(T_OBJECT);
1277 
1278     KlassHandle spec_klass (THREAD, SystemDictionary::ClassLoader_klass());
1279 
1280     // Call public unsynchronized loadClass(String) directly for all class loaders
1281     // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will
1282     // acquire a class-name based lock rather than the class loader object lock.
1283     // JDK < 7 already acquire the class loader lock in loadClass(String, boolean),
1284     // so the call to loadClassInternal() was not required.
1285     //
1286     // UnsyncloadClass flag means both call loadClass(String) and do
1287     // not acquire the class loader lock even for class loaders that are
1288     // not parallelCapable. This was a risky transitional
1289     // flag for diagnostic purposes only. It is risky to call
1290     // custom class loaders without synchronization.
1291     // WARNING If a custom class loader does NOT synchronizer findClass, or callers of
1292     // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field.
1293     // Do NOT assume this will be supported in future releases.
1294     //
1295     // Added MustCallLoadClassInternal in case we discover in the field
1296     // a customer that counts on this call
1297     if (MustCallLoadClassInternal && has_loadClassInternal()) {
1298       JavaCalls::call_special(&result,
1299                               class_loader,
1300                               spec_klass,
1301                               vmSymbols::loadClassInternal_name(),
1302                               vmSymbols::string_class_signature(),
1303                               string,
1304                               CHECK_(nh));
1305     } else {
1306       JavaCalls::call_virtual(&result,
1307                               class_loader,
1308                               spec_klass,
1309                               vmSymbols::loadClass_name(),
1310                               vmSymbols::string_class_signature(),
1311                               string,
1312                               CHECK_(nh));
1313     }
1314 
1315     assert(result.get_type() == T_OBJECT, "just checking");
1316     oop obj = (oop) result.get_jobject();
1317 
1318     // Primitive classes return null since forName() can not be
1319     // used to obtain any of the Class objects representing primitives or void
1320     if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1321       instanceKlassHandle k =
1322                 instanceKlassHandle(THREAD, java_lang_Class::as_Klass(obj));
1323       // For user defined Java class loaders, check that the name returned is
1324       // the same as that requested.  This check is done for the bootstrap
1325       // loader when parsing the class file.
1326       if (class_name == k->name()) {
1327         return k;
1328       }
1329     }
1330     // Class is not found or has the wrong name, return NULL
1331     return nh;
1332   }
1333 }
1334 
1335 void SystemDictionary::define_instance_class(instanceKlassHandle k, TRAPS) {
1336 
1337   ClassLoaderData* loader_data = k->class_loader_data();
1338   Handle class_loader_h(THREAD, loader_data->class_loader());
1339 
1340   for (uintx it = 0; it < GCExpandToAllocateDelayMillis; it++){}
1341 
1342  // for bootstrap and other parallel classloaders don't acquire lock,
1343  // use placeholder token
1344  // If a parallelCapable class loader calls define_instance_class instead of
1345  // find_or_define_instance_class to get here, we have a timing
1346  // hole with systemDictionary updates and check_constraints
1347  if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1348     assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1349          compute_loader_lock_object(class_loader_h, THREAD)),
1350          "define called without lock");
1351   }
1352 
1353   // Check class-loading constraints. Throw exception if violation is detected.
1354   // Grabs and releases SystemDictionary_lock
1355   // The check_constraints/find_class call and update_dictionary sequence
1356   // must be "atomic" for a specific class/classloader pair so we never
1357   // define two different instanceKlasses for that class/classloader pair.
1358   // Existing classloaders will call define_instance_class with the
1359   // classloader lock held
1360   // Parallel classloaders will call find_or_define_instance_class
1361   // which will require a token to perform the define class
1362   Symbol*  name_h = k->name();
1363   unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
1364   int d_index = dictionary()->hash_to_index(d_hash);
1365   check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK);
1366 
1367   // Register class just loaded with class loader (placed in Vector)
1368   // Note we do this before updating the dictionary, as this can
1369   // fail with an OutOfMemoryError (if it does, we will *not* put this
1370   // class in the dictionary and will not update the class hierarchy).
1371   // JVMTI FollowReferences needs to find the classes this way.
1372   if (k->class_loader() != NULL) {
1373     methodHandle m(THREAD, Universe::loader_addClass_method());
1374     JavaValue result(T_VOID);
1375     JavaCallArguments args(class_loader_h);
1376     args.push_oop(Handle(THREAD, k->java_mirror()));
1377     JavaCalls::call(&result, m, &args, CHECK);
1378   }
1379 
1380   // Add the new class. We need recompile lock during update of CHA.
1381   {
1382     unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
1383     int p_index = placeholders()->hash_to_index(p_hash);
1384 
1385     MutexLocker mu_r(Compile_lock, THREAD);
1386 
1387     // Add to class hierarchy, initialize vtables, and do possible
1388     // deoptimizations.
1389     add_to_hierarchy(k, CHECK); // No exception, but can block
1390 
1391     // Add to systemDictionary - so other classes can see it.
1392     // Grabs and releases SystemDictionary_lock
1393     update_dictionary(d_index, d_hash, p_index, p_hash,
1394                       k, class_loader_h, THREAD);
1395   }
1396   k->eager_initialize(THREAD);
1397 
1398   // notify jvmti
1399   if (JvmtiExport::should_post_class_load()) {
1400       assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1401       JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1402 
1403   }
1404 
1405 }
1406 
1407 // Support parallel classloading
1408 // All parallel class loaders, including bootstrap classloader
1409 // lock a placeholder entry for this class/class_loader pair
1410 // to allow parallel defines of different classes for this class loader
1411 // With AllowParallelDefine flag==true, in case they do not synchronize around
1412 // FindLoadedClass/DefineClass, calls, we check for parallel
1413 // loading for them, wait if a defineClass is in progress
1414 // and return the initial requestor's results
1415 // This flag does not apply to the bootstrap classloader.
1416 // With AllowParallelDefine flag==false, call through to define_instance_class
1417 // which will throw LinkageError: duplicate class definition.
1418 // False is the requested default.
1419 // For better performance, the class loaders should synchronize
1420 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1421 // potentially waste time reading and parsing the bytestream.
1422 // Note: VM callers should ensure consistency of k/class_name,class_loader
1423 instanceKlassHandle SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader, instanceKlassHandle k, TRAPS) {
1424 
1425   instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1426   Symbol*  name_h = k->name(); // passed in class_name may be null
1427   ClassLoaderData* loader_data = class_loader_data(class_loader);
1428 
1429   unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
1430   int d_index = dictionary()->hash_to_index(d_hash);
1431 
1432 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1433   unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
1434   int p_index = placeholders()->hash_to_index(p_hash);
1435   PlaceholderEntry* probe;
1436 
1437   {
1438     MutexLocker mu(SystemDictionary_lock, THREAD);
1439     // First check if class already defined
1440     if (UnsyncloadClass || (is_parallelDefine(class_loader))) {
1441       Klass* check = find_class(d_index, d_hash, name_h, loader_data);
1442       if (check != NULL) {
1443         return(instanceKlassHandle(THREAD, check));
1444       }
1445     }
1446 
1447     // Acquire define token for this class/classloader
1448     probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1449     // Wait if another thread defining in parallel
1450     // All threads wait - even those that will throw duplicate class: otherwise
1451     // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1452     // if other thread has not finished updating dictionary
1453     while (probe->definer() != NULL) {
1454       SystemDictionary_lock->wait();
1455     }
1456     // Only special cases allow parallel defines and can use other thread's results
1457     // Other cases fall through, and may run into duplicate defines
1458     // caught by finding an entry in the SystemDictionary
1459     if ((UnsyncloadClass || is_parallelDefine(class_loader)) && (probe->instance_klass() != NULL)) {
1460         placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1461         SystemDictionary_lock->notify_all();
1462 #ifdef ASSERT
1463         Klass* check = find_class(d_index, d_hash, name_h, loader_data);
1464         assert(check != NULL, "definer missed recording success");
1465 #endif
1466         return(instanceKlassHandle(THREAD, probe->instance_klass()));
1467     } else {
1468       // This thread will define the class (even if earlier thread tried and had an error)
1469       probe->set_definer(THREAD);
1470     }
1471   }
1472 
1473   define_instance_class(k, THREAD);
1474 
1475   Handle linkage_exception = Handle(); // null handle
1476 
1477   // definer must notify any waiting threads
1478   {
1479     MutexLocker mu(SystemDictionary_lock, THREAD);
1480     PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1481     assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1482     if (probe != NULL) {
1483       if (HAS_PENDING_EXCEPTION) {
1484         linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1485         CLEAR_PENDING_EXCEPTION;
1486       } else {
1487         probe->set_instance_klass(k());
1488       }
1489       probe->set_definer(NULL);
1490       placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1491       SystemDictionary_lock->notify_all();
1492     }
1493   }
1494 
1495   // Can't throw exception while holding lock due to rank ordering
1496   if (linkage_exception() != NULL) {
1497     THROW_OOP_(linkage_exception(), nh); // throws exception and returns
1498   }
1499 
1500   return k;
1501 }
1502 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1503   // If class_loader is NULL we synchronize on _system_loader_lock_obj
1504   if (class_loader.is_null()) {
1505     return Handle(THREAD, _system_loader_lock_obj);
1506   } else {
1507     return class_loader;
1508   }
1509 }
1510 
1511 // This method is added to check how often we have to wait to grab loader
1512 // lock. The results are being recorded in the performance counters defined in
1513 // ClassLoader::_sync_systemLoaderLockContentionRate and
1514 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1515 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1516   if (!UsePerfData) {
1517     return;
1518   }
1519 
1520   assert(!loader_lock.is_null(), "NULL lock object");
1521 
1522   if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1523       == ObjectSynchronizer::owner_other) {
1524     // contention will likely happen, so increment the corresponding
1525     // contention counter.
1526     if (loader_lock() == _system_loader_lock_obj) {
1527       ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1528     } else {
1529       ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1530     }
1531   }
1532 }
1533 
1534 // ----------------------------------------------------------------------------
1535 // Lookup
1536 
1537 Klass* SystemDictionary::find_class(int index, unsigned int hash,
1538                                       Symbol* class_name,
1539                                       ClassLoaderData* loader_data) {
1540   assert_locked_or_safepoint(SystemDictionary_lock);
1541   assert (index == dictionary()->index_for(class_name, loader_data),
1542           "incorrect index?");
1543 
1544   Klass* k = dictionary()->find_class(index, hash, class_name, loader_data);
1545   return k;
1546 }
1547 
1548 
1549 // Basic find on classes in the midst of being loaded
1550 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1551                                            ClassLoaderData* loader_data) {
1552   assert_locked_or_safepoint(SystemDictionary_lock);
1553   unsigned int p_hash = placeholders()->compute_hash(class_name, loader_data);
1554   int p_index = placeholders()->hash_to_index(p_hash);
1555   return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1556 }
1557 
1558 
1559 // Used for assertions and verification only
1560 Klass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1561   #ifndef ASSERT
1562   guarantee(VerifyBeforeGC      ||
1563             VerifyDuringGC      ||
1564             VerifyBeforeExit    ||
1565             VerifyDuringStartup ||
1566             VerifyAfterGC, "too expensive");
1567   #endif
1568   assert_locked_or_safepoint(SystemDictionary_lock);
1569 
1570   // First look in the loaded class array
1571   unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
1572   int d_index = dictionary()->hash_to_index(d_hash);
1573   return find_class(d_index, d_hash, class_name, loader_data);
1574 }
1575 
1576 
1577 // Get the next class in the diictionary.
1578 Klass* SystemDictionary::try_get_next_class() {
1579   return dictionary()->try_get_next_class();
1580 }
1581 
1582 
1583 // ----------------------------------------------------------------------------
1584 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1585 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1586 // before a new class is used.
1587 
1588 void SystemDictionary::add_to_hierarchy(instanceKlassHandle k, TRAPS) {
1589   assert(k.not_null(), "just checking");
1590   assert_locked_or_safepoint(Compile_lock);
1591 
1592   // Link into hierachy. Make sure the vtables are initialized before linking into
1593   k->append_to_sibling_list();                    // add to superklass/sibling list
1594   k->process_interfaces(THREAD);                  // handle all "implements" declarations
1595   k->set_init_state(InstanceKlass::loaded);
1596   // Now flush all code that depended on old class hierarchy.
1597   // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1598   // Also, first reinitialize vtable because it may have gotten out of synch
1599   // while the new class wasn't connected to the class hierarchy.
1600   Universe::flush_dependents_on(k);
1601 }
1602 
1603 
1604 // ----------------------------------------------------------------------------
1605 // GC support
1606 
1607 // Following roots during mark-sweep is separated in two phases.
1608 //
1609 // The first phase follows preloaded classes and all other system
1610 // classes, since these will never get unloaded anyway.
1611 //
1612 // The second phase removes (unloads) unreachable classes from the
1613 // system dictionary and follows the remaining classes' contents.
1614 
1615 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1616   roots_oops_do(blk, NULL);
1617 }
1618 
1619 void SystemDictionary::always_strong_classes_do(KlassClosure* closure) {
1620   // Follow all system classes and temporary placeholders in dictionary
1621   dictionary()->always_strong_classes_do(closure);
1622 
1623   // Placeholders. These represent classes we're actively loading.
1624   placeholders()->classes_do(closure);
1625 }
1626 
1627 // Calculate a "good" systemdictionary size based
1628 // on predicted or current loaded classes count
1629 int SystemDictionary::calculate_systemdictionary_size(int classcount) {
1630   int newsize = _old_default_sdsize;
1631   if ((classcount > 0)  && !DumpSharedSpaces) {
1632     int desiredsize = classcount/_average_depth_goal;
1633     for (newsize = _primelist[_sdgeneration]; _sdgeneration < _prime_array_size -1;
1634          newsize = _primelist[++_sdgeneration]) {
1635       if (desiredsize <=  newsize) {
1636         break;
1637       }
1638     }
1639   }
1640   return newsize;
1641 }
1642 
1643 #ifdef ASSERT
1644 class VerifySDReachableAndLiveClosure : public OopClosure {
1645 private:
1646   BoolObjectClosure* _is_alive;
1647 
1648   template <class T> void do_oop_work(T* p) {
1649     oop obj = oopDesc::load_decode_heap_oop(p);
1650     guarantee(_is_alive->do_object_b(obj), "Oop in system dictionary must be live");
1651   }
1652 
1653 public:
1654   VerifySDReachableAndLiveClosure(BoolObjectClosure* is_alive) : OopClosure(), _is_alive(is_alive) { }
1655 
1656   virtual void do_oop(oop* p)       { do_oop_work(p); }
1657   virtual void do_oop(narrowOop* p) { do_oop_work(p); }
1658 };
1659 #endif
1660 
1661 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1662 // Note: anonymous classes are not in the SD.
1663 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive) {
1664   // First, mark for unload all ClassLoaderData referencing a dead class loader.
1665   bool has_dead_loaders = ClassLoaderDataGraph::do_unloading(is_alive);
1666   bool unloading_occurred = false;
1667   if (has_dead_loaders) {
1668     unloading_occurred = dictionary()->do_unloading();
1669     constraints()->purge_loader_constraints();
1670     resolution_errors()->purge_resolution_errors();
1671   }
1672   // Oops referenced by the system dictionary may get unreachable independently
1673   // of the class loader (eg. cached protection domain oops). So we need to
1674   // explicitly unlink them here instead of in Dictionary::do_unloading.
1675   dictionary()->unlink(is_alive);
1676 #ifdef ASSERT
1677   VerifySDReachableAndLiveClosure cl(is_alive);
1678   dictionary()->oops_do(&cl);
1679 #endif
1680   return unloading_occurred;
1681 }
1682 
1683 void SystemDictionary::roots_oops_do(OopClosure* strong, OopClosure* weak) {
1684   strong->do_oop(&_java_system_loader);
1685   strong->do_oop(&_system_loader_lock_obj);
1686 
1687   // Adjust dictionary
1688   dictionary()->roots_oops_do(strong, weak);
1689 
1690   // Visit extra methods
1691   invoke_method_table()->oops_do(strong);
1692 }
1693 
1694 void SystemDictionary::oops_do(OopClosure* f) {
1695   f->do_oop(&_java_system_loader);
1696   f->do_oop(&_system_loader_lock_obj);
1697 
1698   // Adjust dictionary
1699   dictionary()->oops_do(f);
1700 
1701   // Visit extra methods
1702   invoke_method_table()->oops_do(f);
1703 }
1704 
1705 // Extended Class redefinition support.
1706 // If one of these classes is replaced, we need to replace it in these places.
1707 // KlassClosure::do_klass should take the address of a class but we can
1708 // change that later.
1709 void SystemDictionary::preloaded_classes_do(KlassClosure* f) {
1710   for (int k = (int)FIRST_WKID; k < (int)WKID_LIMIT; k++) {
1711     f->do_klass(_well_known_klasses[k]);
1712   }
1713 
1714   {
1715     for (int i = 0; i < T_VOID+1; i++) {
1716       if (_box_klasses[i] != NULL) {
1717         assert(i >= T_BOOLEAN, "checking");
1718         f->do_klass(_box_klasses[i]);
1719       }
1720     }
1721   }
1722 
1723   FilteredFieldsMap::classes_do(f);
1724 }
1725 
1726 void SystemDictionary::lazily_loaded_classes_do(KlassClosure* f) {
1727   f->do_klass(_abstract_ownable_synchronizer_klass);
1728 }
1729 
1730 // Just the classes from defining class loaders
1731 // Don't iterate over placeholders
1732 void SystemDictionary::classes_do(void f(Klass*)) {
1733   dictionary()->classes_do(f);
1734 }
1735 
1736 // Added for initialize_itable_for_klass
1737 //   Just the classes from defining class loaders
1738 // Don't iterate over placeholders
1739 void SystemDictionary::classes_do(void f(Klass*, TRAPS), TRAPS) {
1740   dictionary()->classes_do(f, CHECK);
1741 }
1742 
1743 //   All classes, and their class loaders
1744 // Don't iterate over placeholders
1745 void SystemDictionary::classes_do(void f(Klass*, ClassLoaderData*)) {
1746   dictionary()->classes_do(f);
1747 }
1748 
1749 void SystemDictionary::placeholders_do(void f(Symbol*)) {
1750   placeholders()->entries_do(f);
1751 }
1752 
1753 void SystemDictionary::methods_do(void f(Method*)) {
1754   dictionary()->methods_do(f);
1755   invoke_method_table()->methods_do(f);
1756 }
1757 
1758 // ----------------------------------------------------------------------------
1759 // Lazily load klasses
1760 
1761 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
1762   // if multiple threads calling this function, only one thread will load
1763   // the class.  The other threads will find the loaded version once the
1764   // class is loaded.
1765   Klass* aos = _abstract_ownable_synchronizer_klass;
1766   if (aos == NULL) {
1767     Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
1768     // Force a fence to prevent any read before the write completes
1769     OrderAccess::fence();
1770     _abstract_ownable_synchronizer_klass = k;
1771   }
1772 }
1773 
1774 // ----------------------------------------------------------------------------
1775 // Initialization
1776 
1777 void SystemDictionary::initialize(TRAPS) {
1778   // Allocate arrays
1779   assert(dictionary() == NULL,
1780          "SystemDictionary should only be initialized once");
1781   _sdgeneration        = 0;
1782   _dictionary          = new Dictionary(calculate_systemdictionary_size(PredictedLoadedClassCount));
1783   _placeholders        = new PlaceholderTable(_nof_buckets);
1784   _number_of_modifications = 0;
1785   _loader_constraints  = new LoaderConstraintTable(_loader_constraint_size);
1786   _resolution_errors   = new ResolutionErrorTable(_resolution_error_size);
1787   _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
1788 
1789   // Allocate private object used as system class loader lock
1790   _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
1791   // Initialize basic classes
1792   initialize_preloaded_classes(CHECK);
1793 }
1794 
1795 // Compact table of directions on the initialization of klasses:
1796 static const short wk_init_info[] = {
1797   #define WK_KLASS_INIT_INFO(name, symbol, option) \
1798     ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
1799           << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
1800       | (int)SystemDictionary::option ),
1801   WK_KLASSES_DO(WK_KLASS_INIT_INFO)
1802   #undef WK_KLASS_INIT_INFO
1803   0
1804 };
1805 
1806 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
1807   assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1808   int  info = wk_init_info[id - FIRST_WKID];
1809   int  sid  = (info >> CEIL_LG_OPTION_LIMIT);
1810   Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
1811   Klass**    klassp = &_well_known_klasses[id];
1812   bool must_load = (init_opt < SystemDictionary::Opt);
1813   if ((*klassp) == NULL) {
1814     if (must_load) {
1815       (*klassp) = resolve_or_fail(symbol, true, CHECK_0); // load required class
1816     } else {
1817       (*klassp) = resolve_or_null(symbol,       CHECK_0); // load optional klass
1818     }
1819   }
1820   return ((*klassp) != NULL);
1821 }
1822 
1823 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
1824   assert((int)start_id <= (int)limit_id, "IDs are out of order!");
1825   for (int id = (int)start_id; id < (int)limit_id; id++) {
1826     assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1827     int info = wk_init_info[id - FIRST_WKID];
1828     int sid  = (info >> CEIL_LG_OPTION_LIMIT);
1829     int opt  = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
1830 
1831     initialize_wk_klass((WKID)id, opt, CHECK);
1832   }
1833 
1834   // move the starting value forward to the limit:
1835   start_id = limit_id;
1836 }
1837 
1838 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
1839   assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
1840   // Preload commonly used klasses
1841   WKID scan = FIRST_WKID;
1842   // first do Object, then String, Class
1843   if (UseSharedSpaces) {
1844     initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
1845     // Initialize the constant pool for the Object_class
1846     InstanceKlass* ik = InstanceKlass::cast(Object_klass());
1847     ik->constants()->restore_unshareable_info(CHECK);
1848     initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1849   } else {
1850     initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1851   }
1852 
1853   // Calculate offsets for String and Class classes since they are loaded and
1854   // can be used after this point.
1855   java_lang_String::compute_offsets();
1856   java_lang_Class::compute_offsets();
1857 
1858   // Fixup mirrors for classes loaded before java.lang.Class.
1859   // These calls iterate over the objects currently in the perm gen
1860   // so calling them at this point is matters (not before when there
1861   // are fewer objects and not later after there are more objects
1862   // in the perm gen.
1863   Universe::initialize_basic_type_mirrors(CHECK);
1864   Universe::fixup_mirrors(CHECK);
1865 
1866   // do a bunch more:
1867   initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
1868 
1869   // Preload ref klasses and set reference types
1870   InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
1871   InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
1872 
1873   initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
1874   InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
1875   InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
1876   InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
1877   InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
1878 
1879   // JSR 292 classes
1880   WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
1881   WKID jsr292_group_end   = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
1882   initialize_wk_klasses_until(jsr292_group_start, scan, CHECK);
1883   initialize_wk_klasses_through(jsr292_group_end, scan, CHECK);
1884   initialize_wk_klasses_until(WKID_LIMIT, scan, CHECK);
1885 
1886   _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
1887   _box_klasses[T_CHAR]    = WK_KLASS(Character_klass);
1888   _box_klasses[T_FLOAT]   = WK_KLASS(Float_klass);
1889   _box_klasses[T_DOUBLE]  = WK_KLASS(Double_klass);
1890   _box_klasses[T_BYTE]    = WK_KLASS(Byte_klass);
1891   _box_klasses[T_SHORT]   = WK_KLASS(Short_klass);
1892   _box_klasses[T_INT]     = WK_KLASS(Integer_klass);
1893   _box_klasses[T_LONG]    = WK_KLASS(Long_klass);
1894   //_box_klasses[T_OBJECT]  = WK_KLASS(object_klass);
1895   //_box_klasses[T_ARRAY]   = WK_KLASS(object_klass);
1896 
1897   { // Compute whether we should use loadClass or loadClassInternal when loading classes.
1898     Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature());
1899     _has_loadClassInternal = (method != NULL);
1900   }
1901   { // Compute whether we should use checkPackageAccess or NOT
1902     Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
1903     _has_checkPackageAccess = (method != NULL);
1904   }
1905 }
1906 
1907 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
1908 // If so, returns the basic type it holds.  If not, returns T_OBJECT.
1909 BasicType SystemDictionary::box_klass_type(Klass* k) {
1910   assert(k != NULL, "");
1911   for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
1912     if (_box_klasses[i] == k)
1913       return (BasicType)i;
1914   }
1915   return T_OBJECT;
1916 }
1917 
1918 // Constraints on class loaders. The details of the algorithm can be
1919 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
1920 // Virtual Machine" by Sheng Liang and Gilad Bracha.  The basic idea is
1921 // that the system dictionary needs to maintain a set of contraints that
1922 // must be satisfied by all classes in the dictionary.
1923 // if defining is true, then LinkageError if already in systemDictionary
1924 // if initiating loader, then ok if InstanceKlass matches existing entry
1925 
1926 void SystemDictionary::check_constraints(int d_index, unsigned int d_hash,
1927                                          instanceKlassHandle k,
1928                                          Handle class_loader, bool defining,
1929                                          TRAPS) {
1930   const char *linkage_error = NULL;
1931   {
1932     Symbol*  name  = k->name();
1933     ClassLoaderData *loader_data = class_loader_data(class_loader);
1934 
1935     MutexLocker mu(SystemDictionary_lock, THREAD);
1936 
1937     Klass* check = find_class(d_index, d_hash, name, loader_data);
1938     if (check != (Klass*)NULL) {
1939       // if different InstanceKlass - duplicate class definition,
1940       // else - ok, class loaded by a different thread in parallel,
1941       // we should only have found it if it was done loading and ok to use
1942       // system dictionary only holds instance classes, placeholders
1943       // also holds array classes
1944 
1945       assert(check->oop_is_instance(), "noninstance in systemdictionary");
1946       if ((defining == true) || (k() != check)) {
1947         linkage_error = "loader (instance of  %s): attempted  duplicate class "
1948           "definition for name: \"%s\"";
1949       } else {
1950         return;
1951       }
1952     }
1953 
1954 #ifdef ASSERT
1955     Symbol* ph_check = find_placeholder(name, loader_data);
1956     assert(ph_check == NULL || ph_check == name, "invalid symbol");
1957 #endif
1958 
1959     if (linkage_error == NULL) {
1960       if (constraints()->check_or_update(k, class_loader, name) == false) {
1961         linkage_error = "loader constraint violation: loader (instance of %s)"
1962           " previously initiated loading for a different type with name \"%s\"";
1963       }
1964     }
1965   }
1966 
1967   // Throw error now if needed (cannot throw while holding
1968   // SystemDictionary_lock because of rank ordering)
1969 
1970   if (linkage_error) {
1971     ResourceMark rm(THREAD);
1972     const char* class_loader_name = loader_name(class_loader());
1973     char* type_name = k->name()->as_C_string();
1974     size_t buflen = strlen(linkage_error) + strlen(class_loader_name) +
1975       strlen(type_name);
1976     char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
1977     jio_snprintf(buf, buflen, linkage_error, class_loader_name, type_name);
1978     THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
1979   }
1980 }
1981 
1982 
1983 // Update system dictionary - done after check_constraint and add_to_hierachy
1984 // have been called.
1985 void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash,
1986                                          int p_index, unsigned int p_hash,
1987                                          instanceKlassHandle k,
1988                                          Handle class_loader,
1989                                          TRAPS) {
1990   // Compile_lock prevents systemDictionary updates during compilations
1991   assert_locked_or_safepoint(Compile_lock);
1992   Symbol*  name  = k->name();
1993   ClassLoaderData *loader_data = class_loader_data(class_loader);
1994 
1995   {
1996   MutexLocker mu1(SystemDictionary_lock, THREAD);
1997 
1998   // See whether biased locking is enabled and if so set it for this
1999   // klass.
2000   // Note that this must be done past the last potential blocking
2001   // point / safepoint. We enable biased locking lazily using a
2002   // VM_Operation to iterate the SystemDictionary and installing the
2003   // biasable mark word into each InstanceKlass's prototype header.
2004   // To avoid race conditions where we accidentally miss enabling the
2005   // optimization for one class in the process of being added to the
2006   // dictionary, we must not safepoint after the test of
2007   // BiasedLocking::enabled().
2008   if (UseBiasedLocking && BiasedLocking::enabled()) {
2009     // Set biased locking bit for all loaded classes; it will be
2010     // cleared if revocation occurs too often for this type
2011     // NOTE that we must only do this when the class is initally
2012     // defined, not each time it is referenced from a new class loader
2013     if (k->class_loader() == class_loader()) {
2014       k->set_prototype_header(markOopDesc::biased_locking_prototype());
2015     }
2016   }
2017 
2018   // Make a new system dictionary entry.
2019   Klass* sd_check = find_class(d_index, d_hash, name, loader_data);
2020   if (sd_check == NULL) {
2021     dictionary()->add_klass(name, loader_data, k);
2022     notice_modification();
2023   }
2024 #ifdef ASSERT
2025   sd_check = find_class(d_index, d_hash, name, loader_data);
2026   assert (sd_check != NULL, "should have entry in system dictionary");
2027   // Note: there may be a placeholder entry: for circularity testing
2028   // or for parallel defines
2029 #endif
2030     SystemDictionary_lock->notify_all();
2031   }
2032 }
2033 
2034 
2035 // Try to find a class name using the loader constraints.  The
2036 // loader constraints might know about a class that isn't fully loaded
2037 // yet and these will be ignored.
2038 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2039                     Symbol* class_name, Handle class_loader, TRAPS) {
2040 
2041   // First see if it has been loaded directly.
2042   // Force the protection domain to be null.  (This removes protection checks.)
2043   Handle no_protection_domain;
2044   Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2045                                               no_protection_domain, CHECK_NULL);
2046   if (klass != NULL)
2047     return klass;
2048 
2049   // Now look to see if it has been loaded elsewhere, and is subject to
2050   // a loader constraint that would require this loader to return the
2051   // klass that is already loaded.
2052   if (FieldType::is_array(class_name)) {
2053     // For array classes, their Klass*s are not kept in the
2054     // constraint table. The element Klass*s are.
2055     FieldArrayInfo fd;
2056     BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2057     if (t != T_OBJECT) {
2058       klass = Universe::typeArrayKlassObj(t);
2059     } else {
2060       MutexLocker mu(SystemDictionary_lock, THREAD);
2061       klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2062     }
2063     // If element class already loaded, allocate array klass
2064     if (klass != NULL) {
2065       klass = klass->array_klass_or_null(fd.dimension());
2066     }
2067   } else {
2068     MutexLocker mu(SystemDictionary_lock, THREAD);
2069     // Non-array classes are easy: simply check the constraint table.
2070     klass = constraints()->find_constrained_klass(class_name, class_loader);
2071   }
2072 
2073   return klass;
2074 }
2075 
2076 
2077 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2078                                              Handle class_loader1,
2079                                              Handle class_loader2,
2080                                              Thread* THREAD) {
2081   ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2082   ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2083 
2084   Symbol* constraint_name = NULL;
2085   if (!FieldType::is_array(class_name)) {
2086     constraint_name = class_name;
2087   } else {
2088     // For array classes, their Klass*s are not kept in the
2089     // constraint table. The element classes are.
2090     FieldArrayInfo fd;
2091     BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2092     // primitive types always pass
2093     if (t != T_OBJECT) {
2094       return true;
2095     } else {
2096       constraint_name = fd.object_key();
2097     }
2098   }
2099   unsigned int d_hash1 = dictionary()->compute_hash(constraint_name, loader_data1);
2100   int d_index1 = dictionary()->hash_to_index(d_hash1);
2101 
2102   unsigned int d_hash2 = dictionary()->compute_hash(constraint_name, loader_data2);
2103   int d_index2 = dictionary()->hash_to_index(d_hash2);
2104   {
2105   MutexLocker mu_s(SystemDictionary_lock, THREAD);
2106 
2107   // Better never do a GC while we're holding these oops
2108   No_Safepoint_Verifier nosafepoint;
2109 
2110   Klass* klass1 = find_class(d_index1, d_hash1, constraint_name, loader_data1);
2111   Klass* klass2 = find_class(d_index2, d_hash2, constraint_name, loader_data2);
2112   return constraints()->add_entry(constraint_name, klass1, class_loader1,
2113                                   klass2, class_loader2);
2114   }
2115 }
2116 
2117 // Add entry to resolution error table to record the error when the first
2118 // attempt to resolve a reference to a class has failed.
2119 void SystemDictionary::add_resolution_error(constantPoolHandle pool, int which,
2120                                             Symbol* error, Symbol* message) {
2121   unsigned int hash = resolution_errors()->compute_hash(pool, which);
2122   int index = resolution_errors()->hash_to_index(hash);
2123   {
2124     MutexLocker ml(SystemDictionary_lock, Thread::current());
2125     resolution_errors()->add_entry(index, hash, pool, which, error, message);
2126   }
2127 }
2128 
2129 // Delete a resolution error for RedefineClasses for a constant pool is going away
2130 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2131   resolution_errors()->delete_entry(pool);
2132 }
2133 
2134 // Lookup resolution error table. Returns error if found, otherwise NULL.
2135 Symbol* SystemDictionary::find_resolution_error(constantPoolHandle pool, int which,
2136                                                 Symbol** message) {
2137   unsigned int hash = resolution_errors()->compute_hash(pool, which);
2138   int index = resolution_errors()->hash_to_index(hash);
2139   {
2140     MutexLocker ml(SystemDictionary_lock, Thread::current());
2141     ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2142     if (entry != NULL) {
2143       *message = entry->message();
2144       return entry->error();
2145     } else {
2146       return NULL;
2147     }
2148   }
2149 }
2150 
2151 
2152 // Signature constraints ensure that callers and callees agree about
2153 // the meaning of type names in their signatures.  This routine is the
2154 // intake for constraints.  It collects them from several places:
2155 //
2156 //  * LinkResolver::resolve_method (if check_access is true) requires
2157 //    that the resolving class (the caller) and the defining class of
2158 //    the resolved method (the callee) agree on each type in the
2159 //    method's signature.
2160 //
2161 //  * LinkResolver::resolve_interface_method performs exactly the same
2162 //    checks.
2163 //
2164 //  * LinkResolver::resolve_field requires that the constant pool
2165 //    attempting to link to a field agree with the field's defining
2166 //    class about the type of the field signature.
2167 //
2168 //  * klassVtable::initialize_vtable requires that, when a class
2169 //    overrides a vtable entry allocated by a superclass, that the
2170 //    overriding method (i.e., the callee) agree with the superclass
2171 //    on each type in the method's signature.
2172 //
2173 //  * klassItable::initialize_itable requires that, when a class fills
2174 //    in its itables, for each non-abstract method installed in an
2175 //    itable, the method (i.e., the callee) agree with the interface
2176 //    on each type in the method's signature.
2177 //
2178 // All those methods have a boolean (check_access, checkconstraints)
2179 // which turns off the checks.  This is used from specialized contexts
2180 // such as bootstrapping, dumping, and debugging.
2181 //
2182 // No direct constraint is placed between the class and its
2183 // supertypes.  Constraints are only placed along linked relations
2184 // between callers and callees.  When a method overrides or implements
2185 // an abstract method in a supertype (superclass or interface), the
2186 // constraints are placed as if the supertype were the caller to the
2187 // overriding method.  (This works well, since callers to the
2188 // supertype have already established agreement between themselves and
2189 // the supertype.)  As a result of all this, a class can disagree with
2190 // its supertype about the meaning of a type name, as long as that
2191 // class neither calls a relevant method of the supertype, nor is
2192 // called (perhaps via an override) from the supertype.
2193 //
2194 //
2195 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2196 //
2197 // Make sure all class components (including arrays) in the given
2198 // signature will be resolved to the same class in both loaders.
2199 // Returns the name of the type that failed a loader constraint check, or
2200 // NULL if no constraint failed.  No exception except OOME is thrown.
2201 // Arrays are not added to the loader constraint table, their elements are.
2202 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2203                                                Handle loader1, Handle loader2,
2204                                                bool is_method, TRAPS)  {
2205   // Nothing to do if loaders are the same.
2206   if (loader1() == loader2()) {
2207     return NULL;
2208   }
2209 
2210   SignatureStream sig_strm(signature, is_method);
2211   while (!sig_strm.is_done()) {
2212     if (sig_strm.is_object()) {
2213       Symbol* sig = sig_strm.as_symbol(CHECK_NULL);
2214       if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2215         return sig;
2216       }
2217     }
2218     sig_strm.next();
2219   }
2220   return NULL;
2221 }
2222 
2223 
2224 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2225                                                             Symbol* signature,
2226                                                             TRAPS) {
2227   methodHandle empty;
2228   assert(MethodHandles::is_signature_polymorphic(iid) &&
2229          MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2230          iid != vmIntrinsics::_invokeGeneric,
2231          err_msg("must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid)));
2232 
2233   unsigned int hash  = invoke_method_table()->compute_hash(signature, iid);
2234   int          index = invoke_method_table()->hash_to_index(hash);
2235   SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2236   methodHandle m;
2237   if (spe == NULL || spe->method() == NULL) {
2238     spe = NULL;
2239     // Must create lots of stuff here, but outside of the SystemDictionary lock.
2240     m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2241     CompileBroker::compile_method(m, InvocationEntryBci, CompLevel_highest_tier,
2242                                   methodHandle(), CompileThreshold, "MH", CHECK_(empty));
2243 
2244     // Now grab the lock.  We might have to throw away the new method,
2245     // if a racing thread has managed to install one at the same time.
2246     {
2247       MutexLocker ml(SystemDictionary_lock, THREAD);
2248       spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2249       if (spe == NULL)
2250         spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2251       if (spe->method() == NULL)
2252         spe->set_method(m());
2253     }
2254   }
2255 
2256   assert(spe != NULL && spe->method() != NULL, "");
2257   return spe->method();
2258 }
2259 
2260 // Helper for unpacking the return value from linkMethod and linkCallSite.
2261 static methodHandle unpack_method_and_appendix(Handle mname,
2262                                                KlassHandle accessing_klass,
2263                                                objArrayHandle appendix_box,
2264                                                Handle* appendix_result,
2265                                                TRAPS) {
2266   methodHandle empty;
2267   if (mname.not_null()) {
2268     Metadata* vmtarget = java_lang_invoke_MemberName::vmtarget(mname());
2269     if (vmtarget != NULL && vmtarget->is_method()) {
2270       Method* m = (Method*)vmtarget;
2271       oop appendix = appendix_box->obj_at(0);
2272       if (TraceMethodHandles) {
2273     #ifndef PRODUCT
2274         tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2275         m->print();
2276         if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2277         tty->cr();
2278     #endif //PRODUCT
2279       }
2280       (*appendix_result) = Handle(THREAD, appendix);
2281       // the target is stored in the cpCache and if a reference to this
2282       // MethodName is dropped we need a way to make sure the
2283       // class_loader containing this method is kept alive.
2284       // FIXME: the appendix might also preserve this dependency.
2285       ClassLoaderData* this_key = InstanceKlass::cast(accessing_klass())->class_loader_data();
2286       this_key->record_dependency(m->method_holder(), CHECK_NULL); // Can throw OOM
2287       return methodHandle(THREAD, m);
2288     }
2289   }
2290   THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2291   return empty;
2292 }
2293 
2294 methodHandle SystemDictionary::find_method_handle_invoker(Symbol* name,
2295                                                           Symbol* signature,
2296                                                           KlassHandle accessing_klass,
2297                                                           Handle *appendix_result,
2298                                                           Handle *method_type_result,
2299                                                           TRAPS) {
2300   methodHandle empty;
2301   assert(!THREAD->is_Compiler_thread(), "");
2302   Handle method_type =
2303     SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2304   if (false) {  // FIXME: Decide if the Java upcall should resolve signatures.
2305     method_type = java_lang_String::create_from_symbol(signature, CHECK_(empty));
2306   }
2307 
2308   KlassHandle  mh_klass = SystemDictionary::MethodHandle_klass();
2309   int ref_kind = JVM_REF_invokeVirtual;
2310   Handle name_str = StringTable::intern(name, CHECK_(empty));
2311   objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2312   assert(appendix_box->obj_at(0) == NULL, "");
2313 
2314   // This should not happen.  JDK code should take care of that.
2315   if (accessing_klass.is_null() || method_type.is_null()) {
2316     THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
2317   }
2318 
2319   // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2320   JavaCallArguments args;
2321   args.push_oop(accessing_klass()->java_mirror());
2322   args.push_int(ref_kind);
2323   args.push_oop(mh_klass()->java_mirror());
2324   args.push_oop(name_str());
2325   args.push_oop(method_type());
2326   args.push_oop(appendix_box());
2327   JavaValue result(T_OBJECT);
2328   JavaCalls::call_static(&result,
2329                          SystemDictionary::MethodHandleNatives_klass(),
2330                          vmSymbols::linkMethod_name(),
2331                          vmSymbols::linkMethod_signature(),
2332                          &args, CHECK_(empty));
2333   Handle mname(THREAD, (oop) result.get_jobject());
2334   (*method_type_result) = method_type;
2335   return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2336 }
2337 
2338 
2339 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2340 // signature, as interpreted relative to the given class loader.
2341 // Because of class loader constraints, all method handle usage must be
2342 // consistent with this loader.
2343 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2344                                                  KlassHandle accessing_klass,
2345                                                  TRAPS) {
2346   Handle empty;
2347   vmIntrinsics::ID null_iid = vmIntrinsics::_none;  // distinct from all method handle invoker intrinsics
2348   unsigned int hash  = invoke_method_table()->compute_hash(signature, null_iid);
2349   int          index = invoke_method_table()->hash_to_index(hash);
2350   SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2351   if (spe != NULL && spe->method_type() != NULL) {
2352     assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2353     return Handle(THREAD, spe->method_type());
2354   } else if (THREAD->is_Compiler_thread()) {
2355     warning("SystemDictionary::find_method_handle_type called from compiler thread");  // FIXME
2356     return Handle();  // do not attempt from within compiler, unless it was cached
2357   }
2358 
2359   Handle class_loader, protection_domain;
2360   bool is_on_bcp = true;  // keep this true as long as we can materialize from the boot classloader
2361   int npts = ArgumentCount(signature).size();
2362   objArrayHandle pts = oopFactory::new_objArray(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2363   int arg = 0;
2364   Handle rt;                            // the return type from the signature
2365   ResourceMark rm(THREAD);
2366   for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2367     oop mirror = NULL;
2368     if (is_on_bcp) {
2369       // Note:  class_loader & protection_domain are both null at this point.
2370       mirror = ss.as_java_mirror(class_loader, protection_domain,
2371                                  SignatureStream::ReturnNull, CHECK_(empty));
2372       if (mirror == NULL) {
2373         // fall back from BCP to accessing_klass
2374         if (accessing_klass.not_null()) {
2375           class_loader      = Handle(THREAD, InstanceKlass::cast(accessing_klass())->class_loader());
2376           protection_domain = Handle(THREAD, InstanceKlass::cast(accessing_klass())->protection_domain());
2377         }
2378         is_on_bcp = false;
2379       }
2380     }
2381     if (!is_on_bcp) {
2382       // Resolve, throwing a real error if it doesn't work.
2383       mirror = ss.as_java_mirror(class_loader, protection_domain,
2384                                  SignatureStream::NCDFError, CHECK_(empty));
2385     }
2386     if (ss.at_return_type())
2387       rt = Handle(THREAD, mirror);
2388     else
2389       pts->obj_at_put(arg++, mirror);
2390 
2391     // Check accessibility.
2392     if (ss.is_object() && accessing_klass.not_null()) {
2393       Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2394       mirror = NULL;  // safety
2395       // Emulate ConstantPool::verify_constant_pool_resolve.
2396       if (sel_klass->oop_is_objArray())
2397         sel_klass = ObjArrayKlass::cast(sel_klass)->bottom_klass();
2398       if (sel_klass->oop_is_instance()) {
2399         KlassHandle sel_kh(THREAD, sel_klass);
2400         LinkResolver::check_klass_accessability(accessing_klass, sel_kh, CHECK_(empty));
2401       }
2402     }
2403   }
2404   assert(arg == npts, "");
2405 
2406   // call java.lang.invoke.MethodHandleNatives::findMethodType(Class rt, Class[] pts) -> MethodType
2407   JavaCallArguments args(Handle(THREAD, rt()));
2408   args.push_oop(pts());
2409   JavaValue result(T_OBJECT);
2410   JavaCalls::call_static(&result,
2411                          SystemDictionary::MethodHandleNatives_klass(),
2412                          vmSymbols::findMethodHandleType_name(),
2413                          vmSymbols::findMethodHandleType_signature(),
2414                          &args, CHECK_(empty));
2415   Handle method_type(THREAD, (oop) result.get_jobject());
2416 
2417   if (is_on_bcp) {
2418     // We can cache this MethodType inside the JVM.
2419     MutexLocker ml(SystemDictionary_lock, THREAD);
2420     spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2421     if (spe == NULL)
2422       spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2423     if (spe->method_type() == NULL) {
2424       spe->set_method_type(method_type());
2425     }
2426   }
2427 
2428   // report back to the caller with the MethodType
2429   return method_type;
2430 }
2431 
2432 // Ask Java code to find or construct a method handle constant.
2433 Handle SystemDictionary::link_method_handle_constant(KlassHandle caller,
2434                                                      int ref_kind, //e.g., JVM_REF_invokeVirtual
2435                                                      KlassHandle callee,
2436                                                      Symbol* name_sym,
2437                                                      Symbol* signature,
2438                                                      TRAPS) {
2439   Handle empty;
2440   Handle name = java_lang_String::create_from_symbol(name_sym, CHECK_(empty));
2441   Handle type;
2442   if (signature->utf8_length() > 0 && signature->byte_at(0) == '(') {
2443     type = find_method_handle_type(signature, caller, CHECK_(empty));
2444   } else if (caller.is_null()) {
2445     // This should not happen.  JDK code should take care of that.
2446     THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2447   } else {
2448     ResourceMark rm(THREAD);
2449     SignatureStream ss(signature, false);
2450     if (!ss.is_done()) {
2451       oop mirror = ss.as_java_mirror(caller->class_loader(), caller->protection_domain(),
2452                                      SignatureStream::NCDFError, CHECK_(empty));
2453       type = Handle(THREAD, mirror);
2454       ss.next();
2455       if (!ss.is_done())  type = Handle();  // error!
2456     }
2457   }
2458   if (type.is_null()) {
2459     THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad signature", empty);
2460   }
2461 
2462   // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2463   JavaCallArguments args;
2464   args.push_oop(caller->java_mirror());  // the referring class
2465   args.push_int(ref_kind);
2466   args.push_oop(callee->java_mirror());  // the target class
2467   args.push_oop(name());
2468   args.push_oop(type());
2469   JavaValue result(T_OBJECT);
2470   JavaCalls::call_static(&result,
2471                          SystemDictionary::MethodHandleNatives_klass(),
2472                          vmSymbols::linkMethodHandleConstant_name(),
2473                          vmSymbols::linkMethodHandleConstant_signature(),
2474                          &args, CHECK_(empty));
2475   return Handle(THREAD, (oop) result.get_jobject());
2476 }
2477 
2478 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2479 // name and signature, as interpreted relative to the given class loader.
2480 methodHandle SystemDictionary::find_dynamic_call_site_invoker(KlassHandle caller,
2481                                                               Handle bootstrap_specifier,
2482                                                               Symbol* name,
2483                                                               Symbol* type,
2484                                                               Handle *appendix_result,
2485                                                               Handle *method_type_result,
2486                                                               TRAPS) {
2487   methodHandle empty;
2488   Handle bsm, info;
2489   if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2490     bsm = bootstrap_specifier;
2491   } else {
2492     assert(bootstrap_specifier->is_objArray(), "");
2493     objArrayHandle args(THREAD, (objArrayOop) bootstrap_specifier());
2494     int len = args->length();
2495     assert(len >= 1, "");
2496     bsm = Handle(THREAD, args->obj_at(0));
2497     if (len > 1) {
2498       objArrayOop args1 = oopFactory::new_objArray(SystemDictionary::Object_klass(), len-1, CHECK_(empty));
2499       for (int i = 1; i < len; i++)
2500         args1->obj_at_put(i-1, args->obj_at(i));
2501       info = Handle(THREAD, args1);
2502     }
2503   }
2504   guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2505             "caller must supply a valid BSM");
2506 
2507   Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2508   Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2509 
2510   // This should not happen.  JDK code should take care of that.
2511   if (caller.is_null() || method_type.is_null()) {
2512     THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty);
2513   }
2514 
2515   objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2516   assert(appendix_box->obj_at(0) == NULL, "");
2517 
2518   // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, bsm, name, mtype, info, &appendix)
2519   JavaCallArguments args;
2520   args.push_oop(caller->java_mirror());
2521   args.push_oop(bsm());
2522   args.push_oop(method_name());
2523   args.push_oop(method_type());
2524   args.push_oop(info());
2525   args.push_oop(appendix_box);
2526   JavaValue result(T_OBJECT);
2527   JavaCalls::call_static(&result,
2528                          SystemDictionary::MethodHandleNatives_klass(),
2529                          vmSymbols::linkCallSite_name(),
2530                          vmSymbols::linkCallSite_signature(),
2531                          &args, CHECK_(empty));
2532   Handle mname(THREAD, (oop) result.get_jobject());
2533   (*method_type_result) = method_type;
2534   return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
2535 }
2536 
2537 // Since the identity hash code for symbols changes when the symbols are
2538 // moved from the regular perm gen (hash in the mark word) to the shared
2539 // spaces (hash is the address), the classes loaded into the dictionary
2540 // may be in the wrong buckets.
2541 
2542 void SystemDictionary::reorder_dictionary() {
2543   dictionary()->reorder_dictionary();
2544 }
2545 
2546 
2547 void SystemDictionary::copy_buckets(char** top, char* end) {
2548   dictionary()->copy_buckets(top, end);
2549 }
2550 
2551 
2552 void SystemDictionary::copy_table(char** top, char* end) {
2553   dictionary()->copy_table(top, end);
2554 }
2555 
2556 
2557 void SystemDictionary::reverse() {
2558   dictionary()->reverse();
2559 }
2560 
2561 int SystemDictionary::number_of_classes() {
2562   return dictionary()->number_of_entries();
2563 }
2564 
2565 
2566 // ----------------------------------------------------------------------------
2567 #ifndef PRODUCT
2568 
2569 void SystemDictionary::print() {
2570   dictionary()->print();
2571 
2572   // Placeholders
2573   GCMutexLocker mu(SystemDictionary_lock);
2574   placeholders()->print();
2575 
2576   // loader constraints - print under SD_lock
2577   constraints()->print();
2578 }
2579 
2580 #endif
2581 
2582 void SystemDictionary::verify() {
2583   guarantee(dictionary() != NULL, "Verify of system dictionary failed");
2584   guarantee(constraints() != NULL,
2585             "Verify of loader constraints failed");
2586   guarantee(dictionary()->number_of_entries() >= 0 &&
2587             placeholders()->number_of_entries() >= 0,
2588             "Verify of system dictionary failed");
2589 
2590   // Verify dictionary
2591   dictionary()->verify();
2592 
2593   GCMutexLocker mu(SystemDictionary_lock);
2594   placeholders()->verify();
2595 
2596   // Verify constraint table
2597   guarantee(constraints() != NULL, "Verify of loader constraints failed");
2598   constraints()->verify(dictionary(), placeholders());
2599 }
2600 
2601 // utility function for class load event
2602 void SystemDictionary::post_class_load_event(const Ticks& start_time,
2603                                              instanceKlassHandle k,
2604                                              Handle initiating_loader) {
2605 #if INCLUDE_TRACE
2606   EventClassLoad event(UNTIMED);
2607   if (event.should_commit()) {
2608     event.set_starttime(start_time);
2609     event.set_loadedClass(k());
2610     oop defining_class_loader = k->class_loader();
2611     event.set_definingClassLoader(defining_class_loader !=  NULL ?
2612                                     defining_class_loader->klass() : (Klass*)NULL);
2613     oop class_loader = initiating_loader.is_null() ? (oop)NULL : initiating_loader();
2614     event.set_initiatingClassLoader(class_loader != NULL ?
2615                                       class_loader->klass() : (Klass*)NULL);
2616     event.commit();
2617   }
2618 #endif /* INCLUDE_TRACE */
2619 }
2620 
2621 #ifndef PRODUCT
2622 
2623 // statistics code
2624 class ClassStatistics: AllStatic {
2625  private:
2626   static int nclasses;        // number of classes
2627   static int nmethods;        // number of methods
2628   static int nmethoddata;     // number of methodData
2629   static int class_size;      // size of class objects in words
2630   static int method_size;     // size of method objects in words
2631   static int debug_size;      // size of debug info in methods
2632   static int methoddata_size; // size of methodData objects in words
2633 
2634   static void do_class(Klass* k) {
2635     nclasses++;
2636     class_size += k->size();
2637     if (k->oop_is_instance()) {
2638       InstanceKlass* ik = (InstanceKlass*)k;
2639       class_size += ik->methods()->size();
2640       class_size += ik->constants()->size();
2641       class_size += ik->local_interfaces()->size();
2642       class_size += ik->transitive_interfaces()->size();
2643       // We do not have to count implementors, since we only store one!
2644       // SSS: How should these be accounted now that they have moved?
2645       // class_size += ik->fields()->length();
2646     }
2647   }
2648 
2649   static void do_method(Method* m) {
2650     nmethods++;
2651     method_size += m->size();
2652     // class loader uses same objArray for empty vectors, so don't count these
2653     if (m->has_stackmap_table()) {
2654       method_size += m->stackmap_data()->size();
2655     }
2656 
2657     MethodData* mdo = m->method_data();
2658     if (mdo != NULL) {
2659       nmethoddata++;
2660       methoddata_size += mdo->size();
2661     }
2662   }
2663 
2664  public:
2665   static void print() {
2666     SystemDictionary::classes_do(do_class);
2667     SystemDictionary::methods_do(do_method);
2668     tty->print_cr("Class statistics:");
2669     tty->print_cr("%d classes (%d bytes)", nclasses, class_size * oopSize);
2670     tty->print_cr("%d methods (%d bytes = %d base + %d debug info)", nmethods,
2671                   (method_size + debug_size) * oopSize, method_size * oopSize, debug_size * oopSize);
2672     tty->print_cr("%d methoddata (%d bytes)", nmethoddata, methoddata_size * oopSize);
2673   }
2674 };
2675 
2676 
2677 int ClassStatistics::nclasses        = 0;
2678 int ClassStatistics::nmethods        = 0;
2679 int ClassStatistics::nmethoddata     = 0;
2680 int ClassStatistics::class_size      = 0;
2681 int ClassStatistics::method_size     = 0;
2682 int ClassStatistics::debug_size      = 0;
2683 int ClassStatistics::methoddata_size = 0;
2684 
2685 void SystemDictionary::print_class_statistics() {
2686   ResourceMark rm;
2687   ClassStatistics::print();
2688 }
2689 
2690 
2691 class MethodStatistics: AllStatic {
2692  public:
2693   enum {
2694     max_parameter_size = 10
2695   };
2696  private:
2697 
2698   static int _number_of_methods;
2699   static int _number_of_final_methods;
2700   static int _number_of_static_methods;
2701   static int _number_of_native_methods;
2702   static int _number_of_synchronized_methods;
2703   static int _number_of_profiled_methods;
2704   static int _number_of_bytecodes;
2705   static int _parameter_size_profile[max_parameter_size];
2706   static int _bytecodes_profile[Bytecodes::number_of_java_codes];
2707 
2708   static void initialize() {
2709     _number_of_methods        = 0;
2710     _number_of_final_methods  = 0;
2711     _number_of_static_methods = 0;
2712     _number_of_native_methods = 0;
2713     _number_of_synchronized_methods = 0;
2714     _number_of_profiled_methods = 0;
2715     _number_of_bytecodes      = 0;
2716     for (int i = 0; i < max_parameter_size             ; i++) _parameter_size_profile[i] = 0;
2717     for (int j = 0; j < Bytecodes::number_of_java_codes; j++) _bytecodes_profile     [j] = 0;
2718   };
2719 
2720   static void do_method(Method* m) {
2721     _number_of_methods++;
2722     // collect flag info
2723     if (m->is_final()       ) _number_of_final_methods++;
2724     if (m->is_static()      ) _number_of_static_methods++;
2725     if (m->is_native()      ) _number_of_native_methods++;
2726     if (m->is_synchronized()) _number_of_synchronized_methods++;
2727     if (m->method_data() != NULL) _number_of_profiled_methods++;
2728     // collect parameter size info (add one for receiver, if any)
2729     _parameter_size_profile[MIN2(m->size_of_parameters() + (m->is_static() ? 0 : 1), max_parameter_size - 1)]++;
2730     // collect bytecodes info
2731     {
2732       Thread *thread = Thread::current();
2733       HandleMark hm(thread);
2734       BytecodeStream s(methodHandle(thread, m));
2735       Bytecodes::Code c;
2736       while ((c = s.next()) >= 0) {
2737         _number_of_bytecodes++;
2738         _bytecodes_profile[c]++;
2739       }
2740     }
2741   }
2742 
2743  public:
2744   static void print() {
2745     initialize();
2746     SystemDictionary::methods_do(do_method);
2747     // generate output
2748     tty->cr();
2749     tty->print_cr("Method statistics (static):");
2750     // flag distribution
2751     tty->cr();
2752     tty->print_cr("%6d final        methods  %6.1f%%", _number_of_final_methods       , _number_of_final_methods        * 100.0F / _number_of_methods);
2753     tty->print_cr("%6d static       methods  %6.1f%%", _number_of_static_methods      , _number_of_static_methods       * 100.0F / _number_of_methods);
2754     tty->print_cr("%6d native       methods  %6.1f%%", _number_of_native_methods      , _number_of_native_methods       * 100.0F / _number_of_methods);
2755     tty->print_cr("%6d synchronized methods  %6.1f%%", _number_of_synchronized_methods, _number_of_synchronized_methods * 100.0F / _number_of_methods);
2756     tty->print_cr("%6d profiled     methods  %6.1f%%", _number_of_profiled_methods, _number_of_profiled_methods * 100.0F / _number_of_methods);
2757     // parameter size profile
2758     tty->cr();
2759     { int tot = 0;
2760       int avg = 0;
2761       for (int i = 0; i < max_parameter_size; i++) {
2762         int n = _parameter_size_profile[i];
2763         tot += n;
2764         avg += n*i;
2765         tty->print_cr("parameter size = %1d: %6d methods  %5.1f%%", i, n, n * 100.0F / _number_of_methods);
2766       }
2767       assert(tot == _number_of_methods, "should be the same");
2768       tty->print_cr("                    %6d methods  100.0%%", _number_of_methods);
2769       tty->print_cr("(average parameter size = %3.1f including receiver, if any)", (float)avg / _number_of_methods);
2770     }
2771     // bytecodes profile
2772     tty->cr();
2773     { int tot = 0;
2774       for (int i = 0; i < Bytecodes::number_of_java_codes; i++) {
2775         if (Bytecodes::is_defined(i)) {
2776           Bytecodes::Code c = Bytecodes::cast(i);
2777           int n = _bytecodes_profile[c];
2778           tot += n;
2779           tty->print_cr("%9d  %7.3f%%  %s", n, n * 100.0F / _number_of_bytecodes, Bytecodes::name(c));
2780         }
2781       }
2782       assert(tot == _number_of_bytecodes, "should be the same");
2783       tty->print_cr("%9d  100.000%%", _number_of_bytecodes);
2784     }
2785     tty->cr();
2786   }
2787 };
2788 
2789 int MethodStatistics::_number_of_methods;
2790 int MethodStatistics::_number_of_final_methods;
2791 int MethodStatistics::_number_of_static_methods;
2792 int MethodStatistics::_number_of_native_methods;
2793 int MethodStatistics::_number_of_synchronized_methods;
2794 int MethodStatistics::_number_of_profiled_methods;
2795 int MethodStatistics::_number_of_bytecodes;
2796 int MethodStatistics::_parameter_size_profile[MethodStatistics::max_parameter_size];
2797 int MethodStatistics::_bytecodes_profile[Bytecodes::number_of_java_codes];
2798 
2799 
2800 void SystemDictionary::print_method_statistics() {
2801   MethodStatistics::print();
2802 }
2803 
2804 #endif // PRODUCT