rev 7616 : 8067836: The Universe::flush_foo methods belong in CodeCache.
Summary: Move this code to CodeCache.
Reviewed-by: kbarrett, kvn

   1 /*
   2  * Copyright (c) 1997, 2015, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "classfile/classLoaderData.inline.hpp"
  27 #include "classfile/dictionary.hpp"
  28 #include "classfile/javaClasses.hpp"
  29 #include "classfile/loaderConstraints.hpp"
  30 #include "classfile/placeholders.hpp"
  31 #include "classfile/resolutionErrors.hpp"
  32 #include "classfile/stringTable.hpp"
  33 #include "classfile/systemDictionary.hpp"
  34 #include "classfile/vmSymbols.hpp"
  35 #include "code/codeCache.hpp"
  36 #include "compiler/compileBroker.hpp"
  37 #include "interpreter/bytecodeStream.hpp"
  38 #include "interpreter/interpreter.hpp"
  39 #include "memory/filemap.hpp"
  40 #include "memory/gcLocker.hpp"
  41 #include "memory/oopFactory.hpp"
  42 #include "oops/instanceKlass.hpp"
  43 #include "oops/instanceRefKlass.hpp"
  44 #include "oops/klass.inline.hpp"
  45 #include "oops/methodData.hpp"
  46 #include "oops/objArrayKlass.hpp"
  47 #include "oops/oop.inline.hpp"
  48 #include "oops/oop.inline2.hpp"
  49 #include "oops/typeArrayKlass.hpp"
  50 #include "prims/jvmtiEnvBase.hpp"
  51 #include "prims/methodHandles.hpp"
  52 #include "runtime/arguments.hpp"
  53 #include "runtime/biasedLocking.hpp"
  54 #include "runtime/fieldType.hpp"
  55 #include "runtime/handles.inline.hpp"
  56 #include "runtime/java.hpp"
  57 #include "runtime/javaCalls.hpp"
  58 #include "runtime/mutexLocker.hpp"
  59 #include "runtime/orderAccess.inline.hpp"
  60 #include "runtime/signature.hpp"
  61 #include "services/classLoadingService.hpp"
  62 #include "services/threadService.hpp"
  63 #include "utilities/macros.hpp"
  64 #include "utilities/ticks.hpp"
  65 #if INCLUDE_CDS
  66 #include "classfile/sharedClassUtil.hpp"
  67 #include "classfile/systemDictionaryShared.hpp"
  68 #endif
  69 #if INCLUDE_TRACE
  70 #include "trace/tracing.hpp"
  71 #endif
  72 
  73 Dictionary*            SystemDictionary::_dictionary          = NULL;
  74 PlaceholderTable*      SystemDictionary::_placeholders        = NULL;
  75 Dictionary*            SystemDictionary::_shared_dictionary   = NULL;
  76 LoaderConstraintTable* SystemDictionary::_loader_constraints  = NULL;
  77 ResolutionErrorTable*  SystemDictionary::_resolution_errors   = NULL;
  78 SymbolPropertyTable*   SystemDictionary::_invoke_method_table = NULL;
  79 
  80 
  81 int         SystemDictionary::_number_of_modifications = 0;
  82 int         SystemDictionary::_sdgeneration               = 0;
  83 const int   SystemDictionary::_primelist[_prime_array_size] = {1009,2017,4049,5051,10103,
  84               20201,40423,99991};
  85 
  86 oop         SystemDictionary::_system_loader_lock_obj     =  NULL;
  87 
  88 Klass*      SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
  89                                                           =  { NULL /*, NULL...*/ };
  90 
  91 Klass*      SystemDictionary::_box_klasses[T_VOID+1]      =  { NULL /*, NULL...*/ };
  92 
  93 oop         SystemDictionary::_java_system_loader         =  NULL;
  94 
  95 bool        SystemDictionary::_has_loadClassInternal      =  false;
  96 bool        SystemDictionary::_has_checkPackageAccess     =  false;
  97 
  98 // lazily initialized klass variables
  99 Klass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
 100 
 101 
 102 // ----------------------------------------------------------------------------
 103 // Java-level SystemLoader
 104 
 105 oop SystemDictionary::java_system_loader() {
 106   return _java_system_loader;
 107 }
 108 
 109 void SystemDictionary::compute_java_system_loader(TRAPS) {
 110   KlassHandle system_klass(THREAD, WK_KLASS(ClassLoader_klass));
 111   JavaValue result(T_OBJECT);
 112   JavaCalls::call_static(&result,
 113                          KlassHandle(THREAD, WK_KLASS(ClassLoader_klass)),
 114                          vmSymbols::getSystemClassLoader_name(),
 115                          vmSymbols::void_classloader_signature(),
 116                          CHECK);
 117 
 118   _java_system_loader = (oop)result.get_jobject();
 119 
 120   CDS_ONLY(SystemDictionaryShared::initialize(CHECK);)
 121 }
 122 
 123 
 124 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, TRAPS) {
 125   if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
 126   return ClassLoaderDataGraph::find_or_create(class_loader, THREAD);
 127 }
 128 
 129 // ----------------------------------------------------------------------------
 130 // debugging
 131 
 132 #ifdef ASSERT
 133 
 134 // return true if class_name contains no '.' (internal format is '/')
 135 bool SystemDictionary::is_internal_format(Symbol* class_name) {
 136   if (class_name != NULL) {
 137     ResourceMark rm;
 138     char* name = class_name->as_C_string();
 139     return strchr(name, '.') == NULL;
 140   } else {
 141     return true;
 142   }
 143 }
 144 
 145 #endif
 146 
 147 // ----------------------------------------------------------------------------
 148 // Parallel class loading check
 149 
 150 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
 151   if (UnsyncloadClass || class_loader.is_null()) return true;
 152   if (AlwaysLockClassLoader) return false;
 153   return java_lang_ClassLoader::parallelCapable(class_loader());
 154 }
 155 // ----------------------------------------------------------------------------
 156 // ParallelDefineClass flag does not apply to bootclass loader
 157 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
 158    if (class_loader.is_null()) return false;
 159    if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
 160      return true;
 161    }
 162    return false;
 163 }
 164 
 165 /**
 166  * Returns true if the passed class loader is the extension class loader.
 167  */
 168 bool SystemDictionary::is_ext_class_loader(Handle class_loader) {
 169   if (class_loader.is_null()) {
 170     return false;
 171   }
 172   return (class_loader->klass()->name() == vmSymbols::sun_misc_Launcher_ExtClassLoader());
 173 }
 174 
 175 // ----------------------------------------------------------------------------
 176 // Resolving of classes
 177 
 178 // Forwards to resolve_or_null
 179 
 180 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
 181   Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
 182   if (HAS_PENDING_EXCEPTION || klass == NULL) {
 183     KlassHandle k_h(THREAD, klass);
 184     // can return a null klass
 185     klass = handle_resolution_exception(class_name, throw_error, k_h, THREAD);
 186   }
 187   return klass;
 188 }
 189 
 190 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name,
 191                                                      bool throw_error,
 192                                                      KlassHandle klass_h, TRAPS) {
 193   if (HAS_PENDING_EXCEPTION) {
 194     // If we have a pending exception we forward it to the caller, unless throw_error is true,
 195     // in which case we have to check whether the pending exception is a ClassNotFoundException,
 196     // and if so convert it to a NoClassDefFoundError
 197     // And chain the original ClassNotFoundException
 198     if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
 199       ResourceMark rm(THREAD);
 200       assert(klass_h() == NULL, "Should not have result with exception pending");
 201       Handle e(THREAD, PENDING_EXCEPTION);
 202       CLEAR_PENDING_EXCEPTION;
 203       THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
 204     } else {
 205       return NULL;
 206     }
 207   }
 208   // Class not found, throw appropriate error or exception depending on value of throw_error
 209   if (klass_h() == NULL) {
 210     ResourceMark rm(THREAD);
 211     if (throw_error) {
 212       THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
 213     } else {
 214       THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
 215     }
 216   }
 217   return (Klass*)klass_h();
 218 }
 219 
 220 
 221 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
 222                                            bool throw_error, TRAPS)
 223 {
 224   return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
 225 }
 226 
 227 
 228 // Forwards to resolve_instance_class_or_null
 229 
 230 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
 231   assert(!THREAD->is_Compiler_thread(),
 232          err_msg("can not load classes with compiler thread: class=%s, classloader=%s",
 233                  class_name->as_C_string(),
 234                  class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string()));
 235   if (FieldType::is_array(class_name)) {
 236     return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD);
 237   } else if (FieldType::is_obj(class_name)) {
 238     ResourceMark rm(THREAD);
 239     // Ignore wrapping L and ;.
 240     TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
 241                                    class_name->utf8_length() - 2, CHECK_NULL);
 242     return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD);
 243   } else {
 244     return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD);
 245   }
 246 }
 247 
 248 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
 249   return resolve_or_null(class_name, Handle(), Handle(), THREAD);
 250 }
 251 
 252 // Forwards to resolve_instance_class_or_null
 253 
 254 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
 255                                                        Handle class_loader,
 256                                                        Handle protection_domain,
 257                                                        TRAPS) {
 258   assert(FieldType::is_array(class_name), "must be array");
 259   Klass* k = NULL;
 260   FieldArrayInfo fd;
 261   // dimension and object_key in FieldArrayInfo are assigned as a side-effect
 262   // of this call
 263   BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
 264   if (t == T_OBJECT) {
 265     // naked oop "k" is OK here -- we assign back into it
 266     k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
 267                                                          class_loader,
 268                                                          protection_domain,
 269                                                          CHECK_NULL);
 270     if (k != NULL) {
 271       k = k->array_klass(fd.dimension(), CHECK_NULL);
 272     }
 273   } else {
 274     k = Universe::typeArrayKlassObj(t);
 275     k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
 276   }
 277   return k;
 278 }
 279 
 280 
 281 // Must be called for any super-class or super-interface resolution
 282 // during class definition to allow class circularity checking
 283 // super-interface callers:
 284 //    parse_interfaces - for defineClass & jvmtiRedefineClasses
 285 // super-class callers:
 286 //   ClassFileParser - for defineClass & jvmtiRedefineClasses
 287 //   load_shared_class - while loading a class from shared archive
 288 //   resolve_instance_class_or_null:
 289 //     via: handle_parallel_super_load
 290 //      when resolving a class that has an existing placeholder with
 291 //      a saved superclass [i.e. a defineClass is currently in progress]
 292 //      if another thread is trying to resolve the class, it must do
 293 //      super-class checks on its own thread to catch class circularity
 294 // This last call is critical in class circularity checking for cases
 295 // where classloading is delegated to different threads and the
 296 // classloader lock is released.
 297 // Take the case: Base->Super->Base
 298 //   1. If thread T1 tries to do a defineClass of class Base
 299 //    resolve_super_or_fail creates placeholder: T1, Base (super Super)
 300 //   2. resolve_instance_class_or_null does not find SD or placeholder for Super
 301 //    so it tries to load Super
 302 //   3. If we load the class internally, or user classloader uses same thread
 303 //      loadClassFromxxx or defineClass via parseClassFile Super ...
 304 //      3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
 305 //      3.3 resolve_instance_class_or_null Base, finds placeholder for Base
 306 //      3.4 calls resolve_super_or_fail Base
 307 //      3.5 finds T1,Base -> throws class circularity
 308 //OR 4. If T2 tries to resolve Super via defineClass Super ...
 309 //      4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
 310 //      4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
 311 //      4.3 calls resolve_super_or_fail Super in parallel on own thread T2
 312 //      4.4 finds T2, Super -> throws class circularity
 313 // Must be called, even if superclass is null, since this is
 314 // where the placeholder entry is created which claims this
 315 // thread is loading this class/classloader.
 316 Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
 317                                                  Symbol* class_name,
 318                                                  Handle class_loader,
 319                                                  Handle protection_domain,
 320                                                  bool is_superclass,
 321                                                  TRAPS) {
 322   // Double-check, if child class is already loaded, just return super-class,interface
 323   // Don't add a placedholder if already loaded, i.e. already in system dictionary
 324   // Make sure there's a placeholder for the *child* before resolving.
 325   // Used as a claim that this thread is currently loading superclass/classloader
 326   // Used here for ClassCircularity checks and also for heap verification
 327   // (every InstanceKlass in the heap needs to be in the system dictionary
 328   // or have a placeholder).
 329   // Must check ClassCircularity before checking if super class is already loaded
 330   //
 331   // We might not already have a placeholder if this child_name was
 332   // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
 333   // the name of the class might not be known until the stream is actually
 334   // parsed.
 335   // Bugs 4643874, 4715493
 336   // compute_hash can have a safepoint
 337 
 338   ClassLoaderData* loader_data = class_loader_data(class_loader);
 339   unsigned int d_hash = dictionary()->compute_hash(child_name, loader_data);
 340   int d_index = dictionary()->hash_to_index(d_hash);
 341   unsigned int p_hash = placeholders()->compute_hash(child_name, loader_data);
 342   int p_index = placeholders()->hash_to_index(p_hash);
 343   // can't throw error holding a lock
 344   bool child_already_loaded = false;
 345   bool throw_circularity_error = false;
 346   {
 347     MutexLocker mu(SystemDictionary_lock, THREAD);
 348     Klass* childk = find_class(d_index, d_hash, child_name, loader_data);
 349     Klass* quicksuperk;
 350     // to support // loading: if child done loading, just return superclass
 351     // if class_name, & class_loader don't match:
 352     // if initial define, SD update will give LinkageError
 353     // if redefine: compare_class_versions will give HIERARCHY_CHANGED
 354     // so we don't throw an exception here.
 355     // see: nsk redefclass014 & java.lang.instrument Instrument032
 356     if ((childk != NULL ) && (is_superclass) &&
 357        ((quicksuperk = InstanceKlass::cast(childk)->super()) != NULL) &&
 358 
 359          ((quicksuperk->name() == class_name) &&
 360             (quicksuperk->class_loader()  == class_loader()))) {
 361            return quicksuperk;
 362     } else {
 363       PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
 364       if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
 365           throw_circularity_error = true;
 366       }
 367     }
 368     if (!throw_circularity_error) {
 369       PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
 370     }
 371   }
 372   if (throw_circularity_error) {
 373       ResourceMark rm(THREAD);
 374       THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
 375   }
 376 
 377 // java.lang.Object should have been found above
 378   assert(class_name != NULL, "null super class for resolving");
 379   // Resolve the super class or interface, check results on return
 380   Klass* superk = SystemDictionary::resolve_or_null(class_name,
 381                                                  class_loader,
 382                                                  protection_domain,
 383                                                  THREAD);
 384 
 385   KlassHandle superk_h(THREAD, superk);
 386 
 387   // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
 388   // It is no longer necessary to keep the placeholder table alive until update_dictionary
 389   // or error. GC used to walk the placeholder table as strong roots.
 390   // The instanceKlass is kept alive because the class loader is on the stack,
 391   // which keeps the loader_data alive, as well as all instanceKlasses in
 392   // the loader_data. parseClassFile adds the instanceKlass to loader_data.
 393   {
 394     MutexLocker mu(SystemDictionary_lock, THREAD);
 395     placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
 396     SystemDictionary_lock->notify_all();
 397   }
 398   if (HAS_PENDING_EXCEPTION || superk_h() == NULL) {
 399     // can null superk
 400     superk_h = KlassHandle(THREAD, handle_resolution_exception(class_name, true, superk_h, THREAD));
 401   }
 402 
 403   return superk_h();
 404 }
 405 
 406 void SystemDictionary::validate_protection_domain(instanceKlassHandle klass,
 407                                                   Handle class_loader,
 408                                                   Handle protection_domain,
 409                                                   TRAPS) {
 410   if(!has_checkPackageAccess()) return;
 411 
 412   // Now we have to call back to java to check if the initating class has access
 413   JavaValue result(T_VOID);
 414   if (TraceProtectionDomainVerification) {
 415     // Print out trace information
 416     tty->print_cr("Checking package access");
 417     tty->print(" - class loader:      "); class_loader()->print_value_on(tty);      tty->cr();
 418     tty->print(" - protection domain: "); protection_domain()->print_value_on(tty); tty->cr();
 419     tty->print(" - loading:           "); klass()->print_value_on(tty);             tty->cr();
 420   }
 421 
 422   KlassHandle system_loader(THREAD, SystemDictionary::ClassLoader_klass());
 423   JavaCalls::call_special(&result,
 424                          class_loader,
 425                          system_loader,
 426                          vmSymbols::checkPackageAccess_name(),
 427                          vmSymbols::class_protectiondomain_signature(),
 428                          Handle(THREAD, klass->java_mirror()),
 429                          protection_domain,
 430                          THREAD);
 431 
 432   if (TraceProtectionDomainVerification) {
 433     if (HAS_PENDING_EXCEPTION) {
 434       tty->print_cr(" -> DENIED !!!!!!!!!!!!!!!!!!!!!");
 435     } else {
 436      tty->print_cr(" -> granted");
 437     }
 438     tty->cr();
 439   }
 440 
 441   if (HAS_PENDING_EXCEPTION) return;
 442 
 443   // If no exception has been thrown, we have validated the protection domain
 444   // Insert the protection domain of the initiating class into the set.
 445   {
 446     // We recalculate the entry here -- we've called out to java since
 447     // the last time it was calculated.
 448     ClassLoaderData* loader_data = class_loader_data(class_loader);
 449 
 450     Symbol*  kn = klass->name();
 451     unsigned int d_hash = dictionary()->compute_hash(kn, loader_data);
 452     int d_index = dictionary()->hash_to_index(d_hash);
 453 
 454     MutexLocker mu(SystemDictionary_lock, THREAD);
 455     {
 456       // Note that we have an entry, and entries can be deleted only during GC,
 457       // so we cannot allow GC to occur while we're holding this entry.
 458 
 459       // We're using a No_Safepoint_Verifier to catch any place where we
 460       // might potentially do a GC at all.
 461       // Dictionary::do_unloading() asserts that classes in SD are only
 462       // unloaded at a safepoint. Anonymous classes are not in SD.
 463       No_Safepoint_Verifier nosafepoint;
 464       dictionary()->add_protection_domain(d_index, d_hash, klass, loader_data,
 465                                           protection_domain, THREAD);
 466     }
 467   }
 468 }
 469 
 470 // We only get here if this thread finds that another thread
 471 // has already claimed the placeholder token for the current operation,
 472 // but that other thread either never owned or gave up the
 473 // object lock
 474 // Waits on SystemDictionary_lock to indicate placeholder table updated
 475 // On return, caller must recheck placeholder table state
 476 //
 477 // We only get here if
 478 //  1) custom classLoader, i.e. not bootstrap classloader
 479 //  2) UnsyncloadClass not set
 480 //  3) custom classLoader has broken the class loader objectLock
 481 //     so another thread got here in parallel
 482 //
 483 // lockObject must be held.
 484 // Complicated dance due to lock ordering:
 485 // Must first release the classloader object lock to
 486 // allow initial definer to complete the class definition
 487 // and to avoid deadlock
 488 // Reclaim classloader lock object with same original recursion count
 489 // Must release SystemDictionary_lock after notify, since
 490 // class loader lock must be claimed before SystemDictionary_lock
 491 // to prevent deadlocks
 492 //
 493 // The notify allows applications that did an untimed wait() on
 494 // the classloader object lock to not hang.
 495 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
 496   assert_lock_strong(SystemDictionary_lock);
 497 
 498   bool calledholdinglock
 499       = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
 500   assert(calledholdinglock,"must hold lock for notify");
 501   assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
 502   ObjectSynchronizer::notifyall(lockObject, THREAD);
 503   intptr_t recursions =  ObjectSynchronizer::complete_exit(lockObject, THREAD);
 504   SystemDictionary_lock->wait();
 505   SystemDictionary_lock->unlock();
 506   ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
 507   SystemDictionary_lock->lock();
 508 }
 509 
 510 // If the class in is in the placeholder table, class loading is in progress
 511 // For cases where the application changes threads to load classes, it
 512 // is critical to ClassCircularity detection that we try loading
 513 // the superclass on the same thread internally, so we do parallel
 514 // super class loading here.
 515 // This also is critical in cases where the original thread gets stalled
 516 // even in non-circularity situations.
 517 // Note: must call resolve_super_or_fail even if null super -
 518 // to force placeholder entry creation for this class for circularity detection
 519 // Caller must check for pending exception
 520 // Returns non-null Klass* if other thread has completed load
 521 // and we are done,
 522 // If return null Klass* and no pending exception, the caller must load the class
 523 instanceKlassHandle SystemDictionary::handle_parallel_super_load(
 524     Symbol* name, Symbol* superclassname, Handle class_loader,
 525     Handle protection_domain, Handle lockObject, TRAPS) {
 526 
 527   instanceKlassHandle nh = instanceKlassHandle(); // null Handle
 528   ClassLoaderData* loader_data = class_loader_data(class_loader);
 529   unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
 530   int d_index = dictionary()->hash_to_index(d_hash);
 531   unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
 532   int p_index = placeholders()->hash_to_index(p_hash);
 533 
 534   // superk is not used, resolve_super called for circularity check only
 535   // This code is reached in two situations. One if this thread
 536   // is loading the same class twice (e.g. ClassCircularity, or
 537   // java.lang.instrument).
 538   // The second is if another thread started the resolve_super first
 539   // and has not yet finished.
 540   // In both cases the original caller will clean up the placeholder
 541   // entry on error.
 542   Klass* superk = SystemDictionary::resolve_super_or_fail(name,
 543                                                           superclassname,
 544                                                           class_loader,
 545                                                           protection_domain,
 546                                                           true,
 547                                                           CHECK_(nh));
 548 
 549   // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
 550   // Serial class loaders and bootstrap classloader do wait for superclass loads
 551  if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
 552     MutexLocker mu(SystemDictionary_lock, THREAD);
 553     // Check if classloading completed while we were loading superclass or waiting
 554     Klass* check = find_class(d_index, d_hash, name, loader_data);
 555     if (check != NULL) {
 556       // Klass is already loaded, so just return it
 557       return(instanceKlassHandle(THREAD, check));
 558     } else {
 559       return nh;
 560     }
 561   }
 562 
 563   // must loop to both handle other placeholder updates
 564   // and spurious notifications
 565   bool super_load_in_progress = true;
 566   PlaceholderEntry* placeholder;
 567   while (super_load_in_progress) {
 568     MutexLocker mu(SystemDictionary_lock, THREAD);
 569     // Check if classloading completed while we were loading superclass or waiting
 570     Klass* check = find_class(d_index, d_hash, name, loader_data);
 571     if (check != NULL) {
 572       // Klass is already loaded, so just return it
 573       return(instanceKlassHandle(THREAD, check));
 574     } else {
 575       placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
 576       if (placeholder && placeholder->super_load_in_progress() ){
 577         // Before UnsyncloadClass:
 578         // We only get here if the application has released the
 579         // classloader lock when another thread was in the middle of loading a
 580         // superclass/superinterface for this class, and now
 581         // this thread is also trying to load this class.
 582         // To minimize surprises, the first thread that started to
 583         // load a class should be the one to complete the loading
 584         // with the classfile it initially expected.
 585         // This logic has the current thread wait once it has done
 586         // all the superclass/superinterface loading it can, until
 587         // the original thread completes the class loading or fails
 588         // If it completes we will use the resulting InstanceKlass
 589         // which we will find below in the systemDictionary.
 590         // We also get here for parallel bootstrap classloader
 591         if (class_loader.is_null()) {
 592           SystemDictionary_lock->wait();
 593         } else {
 594           double_lock_wait(lockObject, THREAD);
 595         }
 596       } else {
 597         // If not in SD and not in PH, other thread's load must have failed
 598         super_load_in_progress = false;
 599       }
 600     }
 601   }
 602   return (nh);
 603 }
 604 
 605 
 606 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
 607                                                         Handle class_loader,
 608                                                         Handle protection_domain,
 609                                                         TRAPS) {
 610   assert(name != NULL && !FieldType::is_array(name) &&
 611          !FieldType::is_obj(name), "invalid class name");
 612 
 613   Ticks class_load_start_time = Ticks::now();
 614 
 615   // Fix for 4474172; see evaluation for more details
 616   class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
 617   ClassLoaderData *loader_data = register_loader(class_loader, CHECK_NULL);
 618 
 619   // Do lookup to see if class already exist and the protection domain
 620   // has the right access
 621   // This call uses find which checks protection domain already matches
 622   // All subsequent calls use find_class, and set has_loaded_class so that
 623   // before we return a result we call out to java to check for valid protection domain
 624   // to allow returning the Klass* and add it to the pd_set if it is valid
 625   unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
 626   int d_index = dictionary()->hash_to_index(d_hash);
 627   Klass* probe = dictionary()->find(d_index, d_hash, name, loader_data,
 628                                       protection_domain, THREAD);
 629   if (probe != NULL) return probe;
 630 
 631 
 632   // Non-bootstrap class loaders will call out to class loader and
 633   // define via jvm/jni_DefineClass which will acquire the
 634   // class loader object lock to protect against multiple threads
 635   // defining the class in parallel by accident.
 636   // This lock must be acquired here so the waiter will find
 637   // any successful result in the SystemDictionary and not attempt
 638   // the define
 639   // ParallelCapable Classloaders and the bootstrap classloader,
 640   // or all classloaders with UnsyncloadClass do not acquire lock here
 641   bool DoObjectLock = true;
 642   if (is_parallelCapable(class_loader)) {
 643     DoObjectLock = false;
 644   }
 645 
 646   unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
 647   int p_index = placeholders()->hash_to_index(p_hash);
 648 
 649   // Class is not in SystemDictionary so we have to do loading.
 650   // Make sure we are synchronized on the class loader before we proceed
 651   Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
 652   check_loader_lock_contention(lockObject, THREAD);
 653   ObjectLocker ol(lockObject, THREAD, DoObjectLock);
 654 
 655   // Check again (after locking) if class already exist in SystemDictionary
 656   bool class_has_been_loaded   = false;
 657   bool super_load_in_progress  = false;
 658   bool havesupername = false;
 659   instanceKlassHandle k;
 660   PlaceholderEntry* placeholder;
 661   Symbol* superclassname = NULL;
 662 
 663   {
 664     MutexLocker mu(SystemDictionary_lock, THREAD);
 665     Klass* check = find_class(d_index, d_hash, name, loader_data);
 666     if (check != NULL) {
 667       // Klass is already loaded, so just return it
 668       class_has_been_loaded = true;
 669       k = instanceKlassHandle(THREAD, check);
 670     } else {
 671       placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
 672       if (placeholder && placeholder->super_load_in_progress()) {
 673          super_load_in_progress = true;
 674          if (placeholder->havesupername() == true) {
 675            superclassname = placeholder->supername();
 676            havesupername = true;
 677          }
 678       }
 679     }
 680   }
 681 
 682   // If the class is in the placeholder table, class loading is in progress
 683   if (super_load_in_progress && havesupername==true) {
 684     k = SystemDictionary::handle_parallel_super_load(name, superclassname,
 685         class_loader, protection_domain, lockObject, THREAD);
 686     if (HAS_PENDING_EXCEPTION) {
 687       return NULL;
 688     }
 689     if (!k.is_null()) {
 690       class_has_been_loaded = true;
 691     }
 692   }
 693 
 694   bool throw_circularity_error = false;
 695   if (!class_has_been_loaded) {
 696     bool load_instance_added = false;
 697 
 698     // add placeholder entry to record loading instance class
 699     // Five cases:
 700     // All cases need to prevent modifying bootclasssearchpath
 701     // in parallel with a classload of same classname
 702     // Redefineclasses uses existence of the placeholder for the duration
 703     // of the class load to prevent concurrent redefinition of not completely
 704     // defined classes.
 705     // case 1. traditional classloaders that rely on the classloader object lock
 706     //   - no other need for LOAD_INSTANCE
 707     // case 2. traditional classloaders that break the classloader object lock
 708     //    as a deadlock workaround. Detection of this case requires that
 709     //    this check is done while holding the classloader object lock,
 710     //    and that lock is still held when calling classloader's loadClass.
 711     //    For these classloaders, we ensure that the first requestor
 712     //    completes the load and other requestors wait for completion.
 713     // case 3. UnsyncloadClass - don't use objectLocker
 714     //    With this flag, we allow parallel classloading of a
 715     //    class/classloader pair
 716     // case4. Bootstrap classloader - don't own objectLocker
 717     //    This classloader supports parallelism at the classloader level,
 718     //    but only allows a single load of a class/classloader pair.
 719     //    No performance benefit and no deadlock issues.
 720     // case 5. parallelCapable user level classloaders - without objectLocker
 721     //    Allow parallel classloading of a class/classloader pair
 722 
 723     {
 724       MutexLocker mu(SystemDictionary_lock, THREAD);
 725       if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
 726         PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
 727         if (oldprobe) {
 728           // only need check_seen_thread once, not on each loop
 729           // 6341374 java/lang/Instrument with -Xcomp
 730           if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
 731             throw_circularity_error = true;
 732           } else {
 733             // case 1: traditional: should never see load_in_progress.
 734             while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
 735 
 736               // case 4: bootstrap classloader: prevent futile classloading,
 737               // wait on first requestor
 738               if (class_loader.is_null()) {
 739                 SystemDictionary_lock->wait();
 740               } else {
 741               // case 2: traditional with broken classloader lock. wait on first
 742               // requestor.
 743                 double_lock_wait(lockObject, THREAD);
 744               }
 745               // Check if classloading completed while we were waiting
 746               Klass* check = find_class(d_index, d_hash, name, loader_data);
 747               if (check != NULL) {
 748                 // Klass is already loaded, so just return it
 749                 k = instanceKlassHandle(THREAD, check);
 750                 class_has_been_loaded = true;
 751               }
 752               // check if other thread failed to load and cleaned up
 753               oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
 754             }
 755           }
 756         }
 757       }
 758       // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
 759       // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try
 760       // LOAD_INSTANCE in parallel
 761 
 762       if (!throw_circularity_error && !class_has_been_loaded) {
 763         PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
 764         load_instance_added = true;
 765         // For class loaders that do not acquire the classloader object lock,
 766         // if they did not catch another thread holding LOAD_INSTANCE,
 767         // need a check analogous to the acquire ObjectLocker/find_class
 768         // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
 769         // one final check if the load has already completed
 770         // class loaders holding the ObjectLock shouldn't find the class here
 771         Klass* check = find_class(d_index, d_hash, name, loader_data);
 772         if (check != NULL) {
 773         // Klass is already loaded, so return it after checking/adding protection domain
 774           k = instanceKlassHandle(THREAD, check);
 775           class_has_been_loaded = true;
 776         }
 777       }
 778     }
 779 
 780     // must throw error outside of owning lock
 781     if (throw_circularity_error) {
 782       assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
 783       ResourceMark rm(THREAD);
 784       THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
 785     }
 786 
 787     if (!class_has_been_loaded) {
 788 
 789       // Do actual loading
 790       k = load_instance_class(name, class_loader, THREAD);
 791 
 792       // For UnsyncloadClass only
 793       // If they got a linkageError, check if a parallel class load succeeded.
 794       // If it did, then for bytecode resolution the specification requires
 795       // that we return the same result we did for the other thread, i.e. the
 796       // successfully loaded InstanceKlass
 797       // Should not get here for classloaders that support parallelism
 798       // with the new cleaner mechanism, even with AllowParallelDefineClass
 799       // Bootstrap goes through here to allow for an extra guarantee check
 800       if (UnsyncloadClass || (class_loader.is_null())) {
 801         if (k.is_null() && HAS_PENDING_EXCEPTION
 802           && PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass())) {
 803           MutexLocker mu(SystemDictionary_lock, THREAD);
 804           Klass* check = find_class(d_index, d_hash, name, loader_data);
 805           if (check != NULL) {
 806             // Klass is already loaded, so just use it
 807             k = instanceKlassHandle(THREAD, check);
 808             CLEAR_PENDING_EXCEPTION;
 809             guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?");
 810           }
 811         }
 812       }
 813 
 814       // If everything was OK (no exceptions, no null return value), and
 815       // class_loader is NOT the defining loader, do a little more bookkeeping.
 816       if (!HAS_PENDING_EXCEPTION && !k.is_null() &&
 817         k->class_loader() != class_loader()) {
 818 
 819         check_constraints(d_index, d_hash, k, class_loader, false, THREAD);
 820 
 821         // Need to check for a PENDING_EXCEPTION again; check_constraints
 822         // can throw and doesn't use the CHECK macro.
 823         if (!HAS_PENDING_EXCEPTION) {
 824           { // Grabbing the Compile_lock prevents systemDictionary updates
 825             // during compilations.
 826             MutexLocker mu(Compile_lock, THREAD);
 827             update_dictionary(d_index, d_hash, p_index, p_hash,
 828                               k, class_loader, THREAD);
 829           }
 830 
 831           if (JvmtiExport::should_post_class_load()) {
 832             Thread *thread = THREAD;
 833             assert(thread->is_Java_thread(), "thread->is_Java_thread()");
 834             JvmtiExport::post_class_load((JavaThread *) thread, k());
 835           }
 836         }
 837       }
 838     } // load_instance_class loop
 839 
 840     if (load_instance_added == true) {
 841       // clean up placeholder entries for LOAD_INSTANCE success or error
 842       // This brackets the SystemDictionary updates for both defining
 843       // and initiating loaders
 844       MutexLocker mu(SystemDictionary_lock, THREAD);
 845       placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
 846       SystemDictionary_lock->notify_all();
 847     }
 848   }
 849 
 850   if (HAS_PENDING_EXCEPTION || k.is_null()) {
 851     return NULL;
 852   }
 853 
 854   post_class_load_event(class_load_start_time, k, class_loader);
 855 
 856 #ifdef ASSERT
 857   {
 858     ClassLoaderData* loader_data = k->class_loader_data();
 859     MutexLocker mu(SystemDictionary_lock, THREAD);
 860     Klass* kk = find_class(name, loader_data);
 861     assert(kk == k(), "should be present in dictionary");
 862   }
 863 #endif
 864 
 865   // return if the protection domain in NULL
 866   if (protection_domain() == NULL) return k();
 867 
 868   // Check the protection domain has the right access
 869   {
 870     MutexLocker mu(SystemDictionary_lock, THREAD);
 871     // Note that we have an entry, and entries can be deleted only during GC,
 872     // so we cannot allow GC to occur while we're holding this entry.
 873     // We're using a No_Safepoint_Verifier to catch any place where we
 874     // might potentially do a GC at all.
 875     // Dictionary::do_unloading() asserts that classes in SD are only
 876     // unloaded at a safepoint. Anonymous classes are not in SD.
 877     No_Safepoint_Verifier nosafepoint;
 878     if (dictionary()->is_valid_protection_domain(d_index, d_hash, name,
 879                                                  loader_data,
 880                                                  protection_domain)) {
 881       return k();
 882     }
 883   }
 884 
 885   // Verify protection domain. If it fails an exception is thrown
 886   validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
 887 
 888   return k();
 889 }
 890 
 891 
 892 // This routine does not lock the system dictionary.
 893 //
 894 // Since readers don't hold a lock, we must make sure that system
 895 // dictionary entries are only removed at a safepoint (when only one
 896 // thread is running), and are added to in a safe way (all links must
 897 // be updated in an MT-safe manner).
 898 //
 899 // Callers should be aware that an entry could be added just after
 900 // _dictionary->bucket(index) is read here, so the caller will not see
 901 // the new entry.
 902 
 903 Klass* SystemDictionary::find(Symbol* class_name,
 904                               Handle class_loader,
 905                               Handle protection_domain,
 906                               TRAPS) {
 907 
 908   // The result of this call should be consistent with the result
 909   // of the call to resolve_instance_class_or_null().
 910   // See evaluation 6790209 and 4474172 for more details.
 911   class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
 912   ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
 913 
 914   if (loader_data == NULL) {
 915     // If the ClassLoaderData has not been setup,
 916     // then the class loader has no entries in the dictionary.
 917     return NULL;
 918   }
 919 
 920   unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
 921   int d_index = dictionary()->hash_to_index(d_hash);
 922 
 923   {
 924     // Note that we have an entry, and entries can be deleted only during GC,
 925     // so we cannot allow GC to occur while we're holding this entry.
 926     // We're using a No_Safepoint_Verifier to catch any place where we
 927     // might potentially do a GC at all.
 928     // Dictionary::do_unloading() asserts that classes in SD are only
 929     // unloaded at a safepoint. Anonymous classes are not in SD.
 930     No_Safepoint_Verifier nosafepoint;
 931     return dictionary()->find(d_index, d_hash, class_name, loader_data,
 932                               protection_domain, THREAD);
 933   }
 934 }
 935 
 936 
 937 // Look for a loaded instance or array klass by name.  Do not do any loading.
 938 // return NULL in case of error.
 939 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
 940                                                       Handle class_loader,
 941                                                       Handle protection_domain,
 942                                                       TRAPS) {
 943   Klass* k = NULL;
 944   assert(class_name != NULL, "class name must be non NULL");
 945 
 946   if (FieldType::is_array(class_name)) {
 947     // The name refers to an array.  Parse the name.
 948     // dimension and object_key in FieldArrayInfo are assigned as a
 949     // side-effect of this call
 950     FieldArrayInfo fd;
 951     BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
 952     if (t != T_OBJECT) {
 953       k = Universe::typeArrayKlassObj(t);
 954     } else {
 955       k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
 956     }
 957     if (k != NULL) {
 958       k = k->array_klass_or_null(fd.dimension());
 959     }
 960   } else {
 961     k = find(class_name, class_loader, protection_domain, THREAD);
 962   }
 963   return k;
 964 }
 965 
 966 // Note: this method is much like resolve_from_stream, but
 967 // updates no supplemental data structures.
 968 // TODO consolidate the two methods with a helper routine?
 969 Klass* SystemDictionary::parse_stream(Symbol* class_name,
 970                                       Handle class_loader,
 971                                       Handle protection_domain,
 972                                       ClassFileStream* st,
 973                                       KlassHandle host_klass,
 974                                       GrowableArray<Handle>* cp_patches,
 975                                       TRAPS) {
 976   TempNewSymbol parsed_name = NULL;
 977 
 978   Ticks class_load_start_time = Ticks::now();
 979 
 980   ClassLoaderData* loader_data;
 981   if (host_klass.not_null()) {
 982     // Create a new CLD for anonymous class, that uses the same class loader
 983     // as the host_klass
 984     guarantee(host_klass->class_loader() == class_loader(), "should be the same");
 985     guarantee(!DumpSharedSpaces, "must not create anonymous classes when dumping");
 986     loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader(), CHECK_NULL);
 987     loader_data->record_dependency(host_klass(), CHECK_NULL);
 988   } else {
 989     loader_data = ClassLoaderData::class_loader_data(class_loader());
 990   }
 991 
 992   // Parse the stream. Note that we do this even though this klass might
 993   // already be present in the SystemDictionary, otherwise we would not
 994   // throw potential ClassFormatErrors.
 995   //
 996   // Note: "name" is updated.
 997 
 998   instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
 999                                                              loader_data,
1000                                                              protection_domain,
1001                                                              host_klass,
1002                                                              cp_patches,
1003                                                              parsed_name,
1004                                                              true,
1005                                                              THREAD);
1006 
1007 
1008   if (host_klass.not_null() && k.not_null()) {
1009     // If it's anonymous, initialize it now, since nobody else will.
1010 
1011     {
1012       MutexLocker mu_r(Compile_lock, THREAD);
1013 
1014       // Add to class hierarchy, initialize vtables, and do possible
1015       // deoptimizations.
1016       add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1017 
1018       // But, do not add to system dictionary.
1019 
1020       // compiled code dependencies need to be validated anyway
1021       notice_modification();
1022     }
1023 
1024     // Rewrite and patch constant pool here.
1025     k->link_class(CHECK_NULL);
1026     if (cp_patches != NULL) {
1027       k->constants()->patch_resolved_references(cp_patches);
1028     }
1029     k->eager_initialize(CHECK_NULL);
1030 
1031     // notify jvmti
1032     if (JvmtiExport::should_post_class_load()) {
1033         assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1034         JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1035     }
1036 
1037     post_class_load_event(class_load_start_time, k, class_loader);
1038   }
1039   assert(host_klass.not_null() || cp_patches == NULL,
1040          "cp_patches only found with host_klass");
1041 
1042   return k();
1043 }
1044 
1045 // Add a klass to the system from a stream (called by jni_DefineClass and
1046 // JVM_DefineClass).
1047 // Note: class_name can be NULL. In that case we do not know the name of
1048 // the class until we have parsed the stream.
1049 
1050 Klass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1051                                              Handle class_loader,
1052                                              Handle protection_domain,
1053                                              ClassFileStream* st,
1054                                              bool verify,
1055                                              TRAPS) {
1056 
1057   // Classloaders that support parallelism, e.g. bootstrap classloader,
1058   // or all classloaders with UnsyncloadClass do not acquire lock here
1059   bool DoObjectLock = true;
1060   if (is_parallelCapable(class_loader)) {
1061     DoObjectLock = false;
1062   }
1063 
1064   ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL);
1065 
1066   // Make sure we are synchronized on the class loader before we proceed
1067   Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1068   check_loader_lock_contention(lockObject, THREAD);
1069   ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1070 
1071   TempNewSymbol parsed_name = NULL;
1072 
1073   // Parse the stream. Note that we do this even though this klass might
1074   // already be present in the SystemDictionary, otherwise we would not
1075   // throw potential ClassFormatErrors.
1076   //
1077   // Note: "name" is updated.
1078 
1079   instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
1080                                                              loader_data,
1081                                                              protection_domain,
1082                                                              parsed_name,
1083                                                              verify,
1084                                                              THREAD);
1085 
1086   const char* pkg = "java/";
1087   if (!HAS_PENDING_EXCEPTION &&
1088       !class_loader.is_null() &&
1089       parsed_name != NULL &&
1090       !strncmp((const char*)parsed_name->bytes(), pkg, strlen(pkg))) {
1091     // It is illegal to define classes in the "java." package from
1092     // JVM_DefineClass or jni_DefineClass unless you're the bootclassloader
1093     ResourceMark rm(THREAD);
1094     char* name = parsed_name->as_C_string();
1095     char* index = strrchr(name, '/');
1096     *index = '\0'; // chop to just the package name
1097     while ((index = strchr(name, '/')) != NULL) {
1098       *index = '.'; // replace '/' with '.' in package name
1099     }
1100     const char* fmt = "Prohibited package name: %s";
1101     size_t len = strlen(fmt) + strlen(name);
1102     char* message = NEW_RESOURCE_ARRAY(char, len);
1103     jio_snprintf(message, len, fmt, name);
1104     Exceptions::_throw_msg(THREAD_AND_LOCATION,
1105       vmSymbols::java_lang_SecurityException(), message);
1106   }
1107 
1108   if (!HAS_PENDING_EXCEPTION) {
1109     assert(parsed_name != NULL, "Sanity");
1110     assert(class_name == NULL || class_name == parsed_name, "name mismatch");
1111     // Verification prevents us from creating names with dots in them, this
1112     // asserts that that's the case.
1113     assert(is_internal_format(parsed_name),
1114            "external class name format used internally");
1115 
1116     // Add class just loaded
1117     // If a class loader supports parallel classloading handle parallel define requests
1118     // find_or_define_instance_class may return a different InstanceKlass
1119     if (is_parallelCapable(class_loader)) {
1120       k = find_or_define_instance_class(class_name, class_loader, k, THREAD);
1121     } else {
1122       define_instance_class(k, THREAD);
1123     }
1124   }
1125 
1126   // Make sure we have an entry in the SystemDictionary on success
1127   debug_only( {
1128     if (!HAS_PENDING_EXCEPTION) {
1129       assert(parsed_name != NULL, "parsed_name is still null?");
1130       Symbol*  h_name    = k->name();
1131       ClassLoaderData *defining_loader_data = k->class_loader_data();
1132 
1133       MutexLocker mu(SystemDictionary_lock, THREAD);
1134 
1135       Klass* check = find_class(parsed_name, loader_data);
1136       assert(check == k(), "should be present in the dictionary");
1137 
1138       Klass* check2 = find_class(h_name, defining_loader_data);
1139       assert(check == check2, "name inconsistancy in SystemDictionary");
1140     }
1141   } );
1142 
1143   return k();
1144 }
1145 
1146 #if INCLUDE_CDS
1147 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1148                                              int number_of_entries) {
1149   assert(length == _nof_buckets * sizeof(HashtableBucket<mtClass>),
1150          "bad shared dictionary size.");
1151   _shared_dictionary = new Dictionary(_nof_buckets, t, number_of_entries);
1152 }
1153 
1154 
1155 // If there is a shared dictionary, then find the entry for the
1156 // given shared system class, if any.
1157 
1158 Klass* SystemDictionary::find_shared_class(Symbol* class_name) {
1159   if (shared_dictionary() != NULL) {
1160     unsigned int d_hash = shared_dictionary()->compute_hash(class_name, NULL);
1161     int d_index = shared_dictionary()->hash_to_index(d_hash);
1162 
1163     return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1164   } else {
1165     return NULL;
1166   }
1167 }
1168 
1169 
1170 // Load a class from the shared spaces (found through the shared system
1171 // dictionary).  Force the superclass and all interfaces to be loaded.
1172 // Update the class definition to include sibling classes and no
1173 // subclasses (yet).  [Classes in the shared space are not part of the
1174 // object hierarchy until loaded.]
1175 
1176 instanceKlassHandle SystemDictionary::load_shared_class(
1177                  Symbol* class_name, Handle class_loader, TRAPS) {
1178   instanceKlassHandle ik (THREAD, find_shared_class(class_name));
1179   // Make sure we only return the boot class for the NULL classloader.
1180   if (ik.not_null() &&
1181       SharedClassUtil::is_shared_boot_class(ik()) && class_loader.is_null()) {
1182     Handle protection_domain;
1183     return load_shared_class(ik, class_loader, protection_domain, THREAD);
1184   }
1185   return instanceKlassHandle();
1186 }
1187 
1188 instanceKlassHandle SystemDictionary::load_shared_class(instanceKlassHandle ik,
1189                                                         Handle class_loader,
1190                                                         Handle protection_domain, TRAPS) {
1191   if (ik.not_null()) {
1192     instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1193     Symbol* class_name = ik->name();
1194 
1195     // Found the class, now load the superclass and interfaces.  If they
1196     // are shared, add them to the main system dictionary and reset
1197     // their hierarchy references (supers, subs, and interfaces).
1198 
1199     if (ik->super() != NULL) {
1200       Symbol*  cn = ik->super()->name();
1201       resolve_super_or_fail(class_name, cn,
1202                             class_loader, protection_domain, true, CHECK_(nh));
1203     }
1204 
1205     Array<Klass*>* interfaces = ik->local_interfaces();
1206     int num_interfaces = interfaces->length();
1207     for (int index = 0; index < num_interfaces; index++) {
1208       Klass* k = interfaces->at(index);
1209 
1210       // Note: can not use InstanceKlass::cast here because
1211       // interfaces' InstanceKlass's C++ vtbls haven't been
1212       // reinitialized yet (they will be once the interface classes
1213       // are loaded)
1214       Symbol*  name  = k->name();
1215       resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_(nh));
1216     }
1217 
1218     // Adjust methods to recover missing data.  They need addresses for
1219     // interpreter entry points and their default native method address
1220     // must be reset.
1221 
1222     // Updating methods must be done under a lock so multiple
1223     // threads don't update these in parallel
1224     //
1225     // Shared classes are all currently loaded by either the bootstrap or
1226     // internal parallel class loaders, so this will never cause a deadlock
1227     // on a custom class loader lock.
1228 
1229     ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1230     {
1231       Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1232       check_loader_lock_contention(lockObject, THREAD);
1233       ObjectLocker ol(lockObject, THREAD, true);
1234       ik->restore_unshareable_info(loader_data, protection_domain, CHECK_(nh));
1235     }
1236 
1237     if (TraceClassLoading) {
1238       ResourceMark rm;
1239       tty->print("[Loaded %s", ik->external_name());
1240       tty->print(" from shared objects file");
1241       if (class_loader.not_null()) {
1242         tty->print(" by %s", loader_data->loader_name());
1243       }
1244       tty->print_cr("]");
1245     }
1246 
1247     if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1248       // Only dump the classes that can be stored into CDS archive
1249       if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1250         ResourceMark rm(THREAD);
1251         classlist_file->print_cr("%s", ik->name()->as_C_string());
1252         classlist_file->flush();
1253       }
1254     }
1255 
1256     // notify a class loaded from shared object
1257     ClassLoadingService::notify_class_loaded(InstanceKlass::cast(ik()),
1258                                              true /* shared class */);
1259   }
1260   return ik;
1261 }
1262 #endif // INCLUDE_CDS
1263 
1264 instanceKlassHandle SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1265   instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1266   if (class_loader.is_null()) {
1267 
1268     // Search the shared system dictionary for classes preloaded into the
1269     // shared spaces.
1270     instanceKlassHandle k;
1271     {
1272 #if INCLUDE_CDS
1273       PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1274       k = load_shared_class(class_name, class_loader, THREAD);
1275 #endif
1276     }
1277 
1278     if (k.is_null()) {
1279       // Use VM class loader
1280       PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1281       k = ClassLoader::load_classfile(class_name, CHECK_(nh));
1282     }
1283 
1284     // find_or_define_instance_class may return a different InstanceKlass
1285     if (!k.is_null()) {
1286       k = find_or_define_instance_class(class_name, class_loader, k, CHECK_(nh));
1287     }
1288     return k;
1289   } else {
1290     // Use user specified class loader to load class. Call loadClass operation on class_loader.
1291     ResourceMark rm(THREAD);
1292 
1293     assert(THREAD->is_Java_thread(), "must be a JavaThread");
1294     JavaThread* jt = (JavaThread*) THREAD;
1295 
1296     PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1297                                ClassLoader::perf_app_classload_selftime(),
1298                                ClassLoader::perf_app_classload_count(),
1299                                jt->get_thread_stat()->perf_recursion_counts_addr(),
1300                                jt->get_thread_stat()->perf_timers_addr(),
1301                                PerfClassTraceTime::CLASS_LOAD);
1302 
1303     Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nh));
1304     // Translate to external class name format, i.e., convert '/' chars to '.'
1305     Handle string = java_lang_String::externalize_classname(s, CHECK_(nh));
1306 
1307     JavaValue result(T_OBJECT);
1308 
1309     KlassHandle spec_klass (THREAD, SystemDictionary::ClassLoader_klass());
1310 
1311     // Call public unsynchronized loadClass(String) directly for all class loaders
1312     // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will
1313     // acquire a class-name based lock rather than the class loader object lock.
1314     // JDK < 7 already acquire the class loader lock in loadClass(String, boolean),
1315     // so the call to loadClassInternal() was not required.
1316     //
1317     // UnsyncloadClass flag means both call loadClass(String) and do
1318     // not acquire the class loader lock even for class loaders that are
1319     // not parallelCapable. This was a risky transitional
1320     // flag for diagnostic purposes only. It is risky to call
1321     // custom class loaders without synchronization.
1322     // WARNING If a custom class loader does NOT synchronizer findClass, or callers of
1323     // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field.
1324     // Do NOT assume this will be supported in future releases.
1325     //
1326     // Added MustCallLoadClassInternal in case we discover in the field
1327     // a customer that counts on this call
1328     if (MustCallLoadClassInternal && has_loadClassInternal()) {
1329       JavaCalls::call_special(&result,
1330                               class_loader,
1331                               spec_klass,
1332                               vmSymbols::loadClassInternal_name(),
1333                               vmSymbols::string_class_signature(),
1334                               string,
1335                               CHECK_(nh));
1336     } else {
1337       JavaCalls::call_virtual(&result,
1338                               class_loader,
1339                               spec_klass,
1340                               vmSymbols::loadClass_name(),
1341                               vmSymbols::string_class_signature(),
1342                               string,
1343                               CHECK_(nh));
1344     }
1345 
1346     assert(result.get_type() == T_OBJECT, "just checking");
1347     oop obj = (oop) result.get_jobject();
1348 
1349     // Primitive classes return null since forName() can not be
1350     // used to obtain any of the Class objects representing primitives or void
1351     if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1352       instanceKlassHandle k =
1353                 instanceKlassHandle(THREAD, java_lang_Class::as_Klass(obj));
1354       // For user defined Java class loaders, check that the name returned is
1355       // the same as that requested.  This check is done for the bootstrap
1356       // loader when parsing the class file.
1357       if (class_name == k->name()) {
1358         return k;
1359       }
1360     }
1361     // Class is not found or has the wrong name, return NULL
1362     return nh;
1363   }
1364 }
1365 
1366 void SystemDictionary::define_instance_class(instanceKlassHandle k, TRAPS) {
1367 
1368   ClassLoaderData* loader_data = k->class_loader_data();
1369   Handle class_loader_h(THREAD, loader_data->class_loader());
1370 
1371   for (uintx it = 0; it < GCExpandToAllocateDelayMillis; it++){}
1372 
1373  // for bootstrap and other parallel classloaders don't acquire lock,
1374  // use placeholder token
1375  // If a parallelCapable class loader calls define_instance_class instead of
1376  // find_or_define_instance_class to get here, we have a timing
1377  // hole with systemDictionary updates and check_constraints
1378  if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1379     assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1380          compute_loader_lock_object(class_loader_h, THREAD)),
1381          "define called without lock");
1382   }
1383 
1384   // Check class-loading constraints. Throw exception if violation is detected.
1385   // Grabs and releases SystemDictionary_lock
1386   // The check_constraints/find_class call and update_dictionary sequence
1387   // must be "atomic" for a specific class/classloader pair so we never
1388   // define two different instanceKlasses for that class/classloader pair.
1389   // Existing classloaders will call define_instance_class with the
1390   // classloader lock held
1391   // Parallel classloaders will call find_or_define_instance_class
1392   // which will require a token to perform the define class
1393   Symbol*  name_h = k->name();
1394   unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
1395   int d_index = dictionary()->hash_to_index(d_hash);
1396   check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK);
1397 
1398   // Register class just loaded with class loader (placed in Vector)
1399   // Note we do this before updating the dictionary, as this can
1400   // fail with an OutOfMemoryError (if it does, we will *not* put this
1401   // class in the dictionary and will not update the class hierarchy).
1402   // JVMTI FollowReferences needs to find the classes this way.
1403   if (k->class_loader() != NULL) {
1404     methodHandle m(THREAD, Universe::loader_addClass_method());
1405     JavaValue result(T_VOID);
1406     JavaCallArguments args(class_loader_h);
1407     args.push_oop(Handle(THREAD, k->java_mirror()));
1408     JavaCalls::call(&result, m, &args, CHECK);
1409   }
1410 
1411   // Add the new class. We need recompile lock during update of CHA.
1412   {
1413     unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
1414     int p_index = placeholders()->hash_to_index(p_hash);
1415 
1416     MutexLocker mu_r(Compile_lock, THREAD);
1417 
1418     // Add to class hierarchy, initialize vtables, and do possible
1419     // deoptimizations.
1420     add_to_hierarchy(k, CHECK); // No exception, but can block
1421 
1422     // Add to systemDictionary - so other classes can see it.
1423     // Grabs and releases SystemDictionary_lock
1424     update_dictionary(d_index, d_hash, p_index, p_hash,
1425                       k, class_loader_h, THREAD);
1426   }
1427   k->eager_initialize(THREAD);
1428 
1429   // notify jvmti
1430   if (JvmtiExport::should_post_class_load()) {
1431       assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1432       JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1433 
1434   }
1435 
1436 }
1437 
1438 // Support parallel classloading
1439 // All parallel class loaders, including bootstrap classloader
1440 // lock a placeholder entry for this class/class_loader pair
1441 // to allow parallel defines of different classes for this class loader
1442 // With AllowParallelDefine flag==true, in case they do not synchronize around
1443 // FindLoadedClass/DefineClass, calls, we check for parallel
1444 // loading for them, wait if a defineClass is in progress
1445 // and return the initial requestor's results
1446 // This flag does not apply to the bootstrap classloader.
1447 // With AllowParallelDefine flag==false, call through to define_instance_class
1448 // which will throw LinkageError: duplicate class definition.
1449 // False is the requested default.
1450 // For better performance, the class loaders should synchronize
1451 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1452 // potentially waste time reading and parsing the bytestream.
1453 // Note: VM callers should ensure consistency of k/class_name,class_loader
1454 instanceKlassHandle SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader, instanceKlassHandle k, TRAPS) {
1455 
1456   instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1457   Symbol*  name_h = k->name(); // passed in class_name may be null
1458   ClassLoaderData* loader_data = class_loader_data(class_loader);
1459 
1460   unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
1461   int d_index = dictionary()->hash_to_index(d_hash);
1462 
1463 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1464   unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
1465   int p_index = placeholders()->hash_to_index(p_hash);
1466   PlaceholderEntry* probe;
1467 
1468   {
1469     MutexLocker mu(SystemDictionary_lock, THREAD);
1470     // First check if class already defined
1471     if (UnsyncloadClass || (is_parallelDefine(class_loader))) {
1472       Klass* check = find_class(d_index, d_hash, name_h, loader_data);
1473       if (check != NULL) {
1474         return(instanceKlassHandle(THREAD, check));
1475       }
1476     }
1477 
1478     // Acquire define token for this class/classloader
1479     probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1480     // Wait if another thread defining in parallel
1481     // All threads wait - even those that will throw duplicate class: otherwise
1482     // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1483     // if other thread has not finished updating dictionary
1484     while (probe->definer() != NULL) {
1485       SystemDictionary_lock->wait();
1486     }
1487     // Only special cases allow parallel defines and can use other thread's results
1488     // Other cases fall through, and may run into duplicate defines
1489     // caught by finding an entry in the SystemDictionary
1490     if ((UnsyncloadClass || is_parallelDefine(class_loader)) && (probe->instance_klass() != NULL)) {
1491         placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1492         SystemDictionary_lock->notify_all();
1493 #ifdef ASSERT
1494         Klass* check = find_class(d_index, d_hash, name_h, loader_data);
1495         assert(check != NULL, "definer missed recording success");
1496 #endif
1497         return(instanceKlassHandle(THREAD, probe->instance_klass()));
1498     } else {
1499       // This thread will define the class (even if earlier thread tried and had an error)
1500       probe->set_definer(THREAD);
1501     }
1502   }
1503 
1504   define_instance_class(k, THREAD);
1505 
1506   Handle linkage_exception = Handle(); // null handle
1507 
1508   // definer must notify any waiting threads
1509   {
1510     MutexLocker mu(SystemDictionary_lock, THREAD);
1511     PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1512     assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1513     if (probe != NULL) {
1514       if (HAS_PENDING_EXCEPTION) {
1515         linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1516         CLEAR_PENDING_EXCEPTION;
1517       } else {
1518         probe->set_instance_klass(k());
1519       }
1520       probe->set_definer(NULL);
1521       placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1522       SystemDictionary_lock->notify_all();
1523     }
1524   }
1525 
1526   // Can't throw exception while holding lock due to rank ordering
1527   if (linkage_exception() != NULL) {
1528     THROW_OOP_(linkage_exception(), nh); // throws exception and returns
1529   }
1530 
1531   return k;
1532 }
1533 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1534   // If class_loader is NULL we synchronize on _system_loader_lock_obj
1535   if (class_loader.is_null()) {
1536     return Handle(THREAD, _system_loader_lock_obj);
1537   } else {
1538     return class_loader;
1539   }
1540 }
1541 
1542 // This method is added to check how often we have to wait to grab loader
1543 // lock. The results are being recorded in the performance counters defined in
1544 // ClassLoader::_sync_systemLoaderLockContentionRate and
1545 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1546 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1547   if (!UsePerfData) {
1548     return;
1549   }
1550 
1551   assert(!loader_lock.is_null(), "NULL lock object");
1552 
1553   if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1554       == ObjectSynchronizer::owner_other) {
1555     // contention will likely happen, so increment the corresponding
1556     // contention counter.
1557     if (loader_lock() == _system_loader_lock_obj) {
1558       ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1559     } else {
1560       ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1561     }
1562   }
1563 }
1564 
1565 // ----------------------------------------------------------------------------
1566 // Lookup
1567 
1568 Klass* SystemDictionary::find_class(int index, unsigned int hash,
1569                                       Symbol* class_name,
1570                                       ClassLoaderData* loader_data) {
1571   assert_locked_or_safepoint(SystemDictionary_lock);
1572   assert (index == dictionary()->index_for(class_name, loader_data),
1573           "incorrect index?");
1574 
1575   Klass* k = dictionary()->find_class(index, hash, class_name, loader_data);
1576   return k;
1577 }
1578 
1579 
1580 // Basic find on classes in the midst of being loaded
1581 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1582                                            ClassLoaderData* loader_data) {
1583   assert_locked_or_safepoint(SystemDictionary_lock);
1584   unsigned int p_hash = placeholders()->compute_hash(class_name, loader_data);
1585   int p_index = placeholders()->hash_to_index(p_hash);
1586   return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1587 }
1588 
1589 
1590 // Used for assertions and verification only
1591 Klass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1592   #ifndef ASSERT
1593   guarantee(VerifyBeforeGC      ||
1594             VerifyDuringGC      ||
1595             VerifyBeforeExit    ||
1596             VerifyDuringStartup ||
1597             VerifyAfterGC, "too expensive");
1598   #endif
1599   assert_locked_or_safepoint(SystemDictionary_lock);
1600 
1601   // First look in the loaded class array
1602   unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
1603   int d_index = dictionary()->hash_to_index(d_hash);
1604   return find_class(d_index, d_hash, class_name, loader_data);
1605 }
1606 
1607 
1608 // Get the next class in the diictionary.
1609 Klass* SystemDictionary::try_get_next_class() {
1610   return dictionary()->try_get_next_class();
1611 }
1612 
1613 
1614 // ----------------------------------------------------------------------------
1615 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1616 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1617 // before a new class is used.
1618 
1619 void SystemDictionary::add_to_hierarchy(instanceKlassHandle k, TRAPS) {
1620   assert(k.not_null(), "just checking");
1621   assert_locked_or_safepoint(Compile_lock);
1622 
1623   // Link into hierachy. Make sure the vtables are initialized before linking into
1624   k->append_to_sibling_list();                    // add to superklass/sibling list
1625   k->process_interfaces(THREAD);                  // handle all "implements" declarations
1626   k->set_init_state(InstanceKlass::loaded);
1627   // Now flush all code that depended on old class hierarchy.
1628   // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1629   // Also, first reinitialize vtable because it may have gotten out of synch
1630   // while the new class wasn't connected to the class hierarchy.
1631   CodeCache::flush_dependents_on(k);
1632 }
1633 
1634 // ----------------------------------------------------------------------------
1635 // GC support
1636 
1637 // Following roots during mark-sweep is separated in two phases.
1638 //
1639 // The first phase follows preloaded classes and all other system
1640 // classes, since these will never get unloaded anyway.
1641 //
1642 // The second phase removes (unloads) unreachable classes from the
1643 // system dictionary and follows the remaining classes' contents.
1644 
1645 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1646   roots_oops_do(blk, NULL);
1647 }
1648 
1649 void SystemDictionary::always_strong_classes_do(KlassClosure* closure) {
1650   // Follow all system classes and temporary placeholders in dictionary
1651   dictionary()->always_strong_classes_do(closure);
1652 
1653   // Placeholders. These represent classes we're actively loading.
1654   placeholders()->classes_do(closure);
1655 }
1656 
1657 // Calculate a "good" systemdictionary size based
1658 // on predicted or current loaded classes count
1659 int SystemDictionary::calculate_systemdictionary_size(int classcount) {
1660   int newsize = _old_default_sdsize;
1661   if ((classcount > 0)  && !DumpSharedSpaces) {
1662     int desiredsize = classcount/_average_depth_goal;
1663     for (newsize = _primelist[_sdgeneration]; _sdgeneration < _prime_array_size -1;
1664          newsize = _primelist[++_sdgeneration]) {
1665       if (desiredsize <=  newsize) {
1666         break;
1667       }
1668     }
1669   }
1670   return newsize;
1671 }
1672 
1673 #ifdef ASSERT
1674 class VerifySDReachableAndLiveClosure : public OopClosure {
1675 private:
1676   BoolObjectClosure* _is_alive;
1677 
1678   template <class T> void do_oop_work(T* p) {
1679     oop obj = oopDesc::load_decode_heap_oop(p);
1680     guarantee(_is_alive->do_object_b(obj), "Oop in system dictionary must be live");
1681   }
1682 
1683 public:
1684   VerifySDReachableAndLiveClosure(BoolObjectClosure* is_alive) : OopClosure(), _is_alive(is_alive) { }
1685 
1686   virtual void do_oop(oop* p)       { do_oop_work(p); }
1687   virtual void do_oop(narrowOop* p) { do_oop_work(p); }
1688 };
1689 #endif
1690 
1691 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1692 // Note: anonymous classes are not in the SD.
1693 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive, bool clean_alive) {
1694   // First, mark for unload all ClassLoaderData referencing a dead class loader.
1695   bool unloading_occurred = ClassLoaderDataGraph::do_unloading(is_alive, clean_alive);
1696   if (unloading_occurred) {
1697     dictionary()->do_unloading();
1698     constraints()->purge_loader_constraints();
1699     resolution_errors()->purge_resolution_errors();
1700   }
1701   // Oops referenced by the system dictionary may get unreachable independently
1702   // of the class loader (eg. cached protection domain oops). So we need to
1703   // explicitly unlink them here instead of in Dictionary::do_unloading.
1704   dictionary()->unlink(is_alive);
1705 #ifdef ASSERT
1706   VerifySDReachableAndLiveClosure cl(is_alive);
1707   dictionary()->oops_do(&cl);
1708 #endif
1709   return unloading_occurred;
1710 }
1711 
1712 void SystemDictionary::roots_oops_do(OopClosure* strong, OopClosure* weak) {
1713   strong->do_oop(&_java_system_loader);
1714   strong->do_oop(&_system_loader_lock_obj);
1715   CDS_ONLY(SystemDictionaryShared::roots_oops_do(strong);)
1716 
1717   // Adjust dictionary
1718   dictionary()->roots_oops_do(strong, weak);
1719 
1720   // Visit extra methods
1721   invoke_method_table()->oops_do(strong);
1722 }
1723 
1724 void SystemDictionary::oops_do(OopClosure* f) {
1725   f->do_oop(&_java_system_loader);
1726   f->do_oop(&_system_loader_lock_obj);
1727   CDS_ONLY(SystemDictionaryShared::oops_do(f);)
1728 
1729   // Adjust dictionary
1730   dictionary()->oops_do(f);
1731 
1732   // Visit extra methods
1733   invoke_method_table()->oops_do(f);
1734 }
1735 
1736 // Extended Class redefinition support.
1737 // If one of these classes is replaced, we need to replace it in these places.
1738 // KlassClosure::do_klass should take the address of a class but we can
1739 // change that later.
1740 void SystemDictionary::preloaded_classes_do(KlassClosure* f) {
1741   for (int k = (int)FIRST_WKID; k < (int)WKID_LIMIT; k++) {
1742     f->do_klass(_well_known_klasses[k]);
1743   }
1744 
1745   {
1746     for (int i = 0; i < T_VOID+1; i++) {
1747       if (_box_klasses[i] != NULL) {
1748         assert(i >= T_BOOLEAN, "checking");
1749         f->do_klass(_box_klasses[i]);
1750       }
1751     }
1752   }
1753 
1754   FilteredFieldsMap::classes_do(f);
1755 }
1756 
1757 void SystemDictionary::lazily_loaded_classes_do(KlassClosure* f) {
1758   f->do_klass(_abstract_ownable_synchronizer_klass);
1759 }
1760 
1761 // Just the classes from defining class loaders
1762 // Don't iterate over placeholders
1763 void SystemDictionary::classes_do(void f(Klass*)) {
1764   dictionary()->classes_do(f);
1765 }
1766 
1767 // Added for initialize_itable_for_klass
1768 //   Just the classes from defining class loaders
1769 // Don't iterate over placeholders
1770 void SystemDictionary::classes_do(void f(Klass*, TRAPS), TRAPS) {
1771   dictionary()->classes_do(f, CHECK);
1772 }
1773 
1774 //   All classes, and their class loaders
1775 // Don't iterate over placeholders
1776 void SystemDictionary::classes_do(void f(Klass*, ClassLoaderData*)) {
1777   dictionary()->classes_do(f);
1778 }
1779 
1780 void SystemDictionary::placeholders_do(void f(Symbol*)) {
1781   placeholders()->entries_do(f);
1782 }
1783 
1784 void SystemDictionary::methods_do(void f(Method*)) {
1785   dictionary()->methods_do(f);
1786   invoke_method_table()->methods_do(f);
1787 }
1788 
1789 void SystemDictionary::remove_classes_in_error_state() {
1790   dictionary()->remove_classes_in_error_state();
1791 }
1792 
1793 // ----------------------------------------------------------------------------
1794 // Lazily load klasses
1795 
1796 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
1797   // if multiple threads calling this function, only one thread will load
1798   // the class.  The other threads will find the loaded version once the
1799   // class is loaded.
1800   Klass* aos = _abstract_ownable_synchronizer_klass;
1801   if (aos == NULL) {
1802     Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
1803     // Force a fence to prevent any read before the write completes
1804     OrderAccess::fence();
1805     _abstract_ownable_synchronizer_klass = k;
1806   }
1807 }
1808 
1809 // ----------------------------------------------------------------------------
1810 // Initialization
1811 
1812 void SystemDictionary::initialize(TRAPS) {
1813   // Allocate arrays
1814   assert(dictionary() == NULL,
1815          "SystemDictionary should only be initialized once");
1816   _sdgeneration        = 0;
1817   _dictionary          = new Dictionary(calculate_systemdictionary_size(PredictedLoadedClassCount));
1818   _placeholders        = new PlaceholderTable(_nof_buckets);
1819   _number_of_modifications = 0;
1820   _loader_constraints  = new LoaderConstraintTable(_loader_constraint_size);
1821   _resolution_errors   = new ResolutionErrorTable(_resolution_error_size);
1822   _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
1823 
1824   // Allocate private object used as system class loader lock
1825   _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
1826   // Initialize basic classes
1827   initialize_preloaded_classes(CHECK);
1828 }
1829 
1830 // Compact table of directions on the initialization of klasses:
1831 static const short wk_init_info[] = {
1832   #define WK_KLASS_INIT_INFO(name, symbol, option) \
1833     ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
1834           << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
1835       | (int)SystemDictionary::option ),
1836   WK_KLASSES_DO(WK_KLASS_INIT_INFO)
1837   #undef WK_KLASS_INIT_INFO
1838   0
1839 };
1840 
1841 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
1842   assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1843   int  info = wk_init_info[id - FIRST_WKID];
1844   int  sid  = (info >> CEIL_LG_OPTION_LIMIT);
1845   Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
1846   Klass**    klassp = &_well_known_klasses[id];
1847   bool must_load = (init_opt < SystemDictionary::Opt);
1848   if ((*klassp) == NULL) {
1849     if (must_load) {
1850       (*klassp) = resolve_or_fail(symbol, true, CHECK_0); // load required class
1851     } else {
1852       (*klassp) = resolve_or_null(symbol,       CHECK_0); // load optional klass
1853     }
1854   }
1855   return ((*klassp) != NULL);
1856 }
1857 
1858 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
1859   assert((int)start_id <= (int)limit_id, "IDs are out of order!");
1860   for (int id = (int)start_id; id < (int)limit_id; id++) {
1861     assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1862     int info = wk_init_info[id - FIRST_WKID];
1863     int sid  = (info >> CEIL_LG_OPTION_LIMIT);
1864     int opt  = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
1865 
1866     initialize_wk_klass((WKID)id, opt, CHECK);
1867   }
1868 
1869   // move the starting value forward to the limit:
1870   start_id = limit_id;
1871 }
1872 
1873 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
1874   assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
1875   // Preload commonly used klasses
1876   WKID scan = FIRST_WKID;
1877   // first do Object, then String, Class
1878   if (UseSharedSpaces) {
1879     initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
1880     // Initialize the constant pool for the Object_class
1881     InstanceKlass* ik = InstanceKlass::cast(Object_klass());
1882     ik->constants()->restore_unshareable_info(CHECK);
1883     initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1884   } else {
1885     initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1886   }
1887 
1888   // Calculate offsets for String and Class classes since they are loaded and
1889   // can be used after this point.
1890   java_lang_String::compute_offsets();
1891   java_lang_Class::compute_offsets();
1892 
1893   // Fixup mirrors for classes loaded before java.lang.Class.
1894   // These calls iterate over the objects currently in the perm gen
1895   // so calling them at this point is matters (not before when there
1896   // are fewer objects and not later after there are more objects
1897   // in the perm gen.
1898   Universe::initialize_basic_type_mirrors(CHECK);
1899   Universe::fixup_mirrors(CHECK);
1900 
1901   // do a bunch more:
1902   initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
1903 
1904   // Preload ref klasses and set reference types
1905   InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
1906   InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
1907 
1908   initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
1909   InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
1910   InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
1911   InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
1912   InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
1913 
1914   // JSR 292 classes
1915   WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
1916   WKID jsr292_group_end   = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
1917   initialize_wk_klasses_until(jsr292_group_start, scan, CHECK);
1918   initialize_wk_klasses_through(jsr292_group_end, scan, CHECK);
1919   initialize_wk_klasses_until(WKID_LIMIT, scan, CHECK);
1920 
1921   _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
1922   _box_klasses[T_CHAR]    = WK_KLASS(Character_klass);
1923   _box_klasses[T_FLOAT]   = WK_KLASS(Float_klass);
1924   _box_klasses[T_DOUBLE]  = WK_KLASS(Double_klass);
1925   _box_klasses[T_BYTE]    = WK_KLASS(Byte_klass);
1926   _box_klasses[T_SHORT]   = WK_KLASS(Short_klass);
1927   _box_klasses[T_INT]     = WK_KLASS(Integer_klass);
1928   _box_klasses[T_LONG]    = WK_KLASS(Long_klass);
1929   //_box_klasses[T_OBJECT]  = WK_KLASS(object_klass);
1930   //_box_klasses[T_ARRAY]   = WK_KLASS(object_klass);
1931 
1932   { // Compute whether we should use loadClass or loadClassInternal when loading classes.
1933     Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature());
1934     _has_loadClassInternal = (method != NULL);
1935   }
1936   { // Compute whether we should use checkPackageAccess or NOT
1937     Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
1938     _has_checkPackageAccess = (method != NULL);
1939   }
1940 }
1941 
1942 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
1943 // If so, returns the basic type it holds.  If not, returns T_OBJECT.
1944 BasicType SystemDictionary::box_klass_type(Klass* k) {
1945   assert(k != NULL, "");
1946   for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
1947     if (_box_klasses[i] == k)
1948       return (BasicType)i;
1949   }
1950   return T_OBJECT;
1951 }
1952 
1953 // Constraints on class loaders. The details of the algorithm can be
1954 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
1955 // Virtual Machine" by Sheng Liang and Gilad Bracha.  The basic idea is
1956 // that the system dictionary needs to maintain a set of contraints that
1957 // must be satisfied by all classes in the dictionary.
1958 // if defining is true, then LinkageError if already in systemDictionary
1959 // if initiating loader, then ok if InstanceKlass matches existing entry
1960 
1961 void SystemDictionary::check_constraints(int d_index, unsigned int d_hash,
1962                                          instanceKlassHandle k,
1963                                          Handle class_loader, bool defining,
1964                                          TRAPS) {
1965   const char *linkage_error = NULL;
1966   {
1967     Symbol*  name  = k->name();
1968     ClassLoaderData *loader_data = class_loader_data(class_loader);
1969 
1970     MutexLocker mu(SystemDictionary_lock, THREAD);
1971 
1972     Klass* check = find_class(d_index, d_hash, name, loader_data);
1973     if (check != (Klass*)NULL) {
1974       // if different InstanceKlass - duplicate class definition,
1975       // else - ok, class loaded by a different thread in parallel,
1976       // we should only have found it if it was done loading and ok to use
1977       // system dictionary only holds instance classes, placeholders
1978       // also holds array classes
1979 
1980       assert(check->oop_is_instance(), "noninstance in systemdictionary");
1981       if ((defining == true) || (k() != check)) {
1982         linkage_error = "loader (instance of  %s): attempted  duplicate class "
1983           "definition for name: \"%s\"";
1984       } else {
1985         return;
1986       }
1987     }
1988 
1989 #ifdef ASSERT
1990     Symbol* ph_check = find_placeholder(name, loader_data);
1991     assert(ph_check == NULL || ph_check == name, "invalid symbol");
1992 #endif
1993 
1994     if (linkage_error == NULL) {
1995       if (constraints()->check_or_update(k, class_loader, name) == false) {
1996         linkage_error = "loader constraint violation: loader (instance of %s)"
1997           " previously initiated loading for a different type with name \"%s\"";
1998       }
1999     }
2000   }
2001 
2002   // Throw error now if needed (cannot throw while holding
2003   // SystemDictionary_lock because of rank ordering)
2004 
2005   if (linkage_error) {
2006     ResourceMark rm(THREAD);
2007     const char* class_loader_name = loader_name(class_loader());
2008     char* type_name = k->name()->as_C_string();
2009     size_t buflen = strlen(linkage_error) + strlen(class_loader_name) +
2010       strlen(type_name);
2011     char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
2012     jio_snprintf(buf, buflen, linkage_error, class_loader_name, type_name);
2013     THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
2014   }
2015 }
2016 
2017 
2018 // Update system dictionary - done after check_constraint and add_to_hierachy
2019 // have been called.
2020 void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash,
2021                                          int p_index, unsigned int p_hash,
2022                                          instanceKlassHandle k,
2023                                          Handle class_loader,
2024                                          TRAPS) {
2025   // Compile_lock prevents systemDictionary updates during compilations
2026   assert_locked_or_safepoint(Compile_lock);
2027   Symbol*  name  = k->name();
2028   ClassLoaderData *loader_data = class_loader_data(class_loader);
2029 
2030   {
2031   MutexLocker mu1(SystemDictionary_lock, THREAD);
2032 
2033   // See whether biased locking is enabled and if so set it for this
2034   // klass.
2035   // Note that this must be done past the last potential blocking
2036   // point / safepoint. We enable biased locking lazily using a
2037   // VM_Operation to iterate the SystemDictionary and installing the
2038   // biasable mark word into each InstanceKlass's prototype header.
2039   // To avoid race conditions where we accidentally miss enabling the
2040   // optimization for one class in the process of being added to the
2041   // dictionary, we must not safepoint after the test of
2042   // BiasedLocking::enabled().
2043   if (UseBiasedLocking && BiasedLocking::enabled()) {
2044     // Set biased locking bit for all loaded classes; it will be
2045     // cleared if revocation occurs too often for this type
2046     // NOTE that we must only do this when the class is initally
2047     // defined, not each time it is referenced from a new class loader
2048     if (k->class_loader() == class_loader()) {
2049       k->set_prototype_header(markOopDesc::biased_locking_prototype());
2050     }
2051   }
2052 
2053   // Make a new system dictionary entry.
2054   Klass* sd_check = find_class(d_index, d_hash, name, loader_data);
2055   if (sd_check == NULL) {
2056     dictionary()->add_klass(name, loader_data, k);
2057     notice_modification();
2058   }
2059 #ifdef ASSERT
2060   sd_check = find_class(d_index, d_hash, name, loader_data);
2061   assert (sd_check != NULL, "should have entry in system dictionary");
2062   // Note: there may be a placeholder entry: for circularity testing
2063   // or for parallel defines
2064 #endif
2065     SystemDictionary_lock->notify_all();
2066   }
2067 }
2068 
2069 
2070 // Try to find a class name using the loader constraints.  The
2071 // loader constraints might know about a class that isn't fully loaded
2072 // yet and these will be ignored.
2073 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2074                     Symbol* class_name, Handle class_loader, TRAPS) {
2075 
2076   // First see if it has been loaded directly.
2077   // Force the protection domain to be null.  (This removes protection checks.)
2078   Handle no_protection_domain;
2079   Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2080                                               no_protection_domain, CHECK_NULL);
2081   if (klass != NULL)
2082     return klass;
2083 
2084   // Now look to see if it has been loaded elsewhere, and is subject to
2085   // a loader constraint that would require this loader to return the
2086   // klass that is already loaded.
2087   if (FieldType::is_array(class_name)) {
2088     // For array classes, their Klass*s are not kept in the
2089     // constraint table. The element Klass*s are.
2090     FieldArrayInfo fd;
2091     BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2092     if (t != T_OBJECT) {
2093       klass = Universe::typeArrayKlassObj(t);
2094     } else {
2095       MutexLocker mu(SystemDictionary_lock, THREAD);
2096       klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2097     }
2098     // If element class already loaded, allocate array klass
2099     if (klass != NULL) {
2100       klass = klass->array_klass_or_null(fd.dimension());
2101     }
2102   } else {
2103     MutexLocker mu(SystemDictionary_lock, THREAD);
2104     // Non-array classes are easy: simply check the constraint table.
2105     klass = constraints()->find_constrained_klass(class_name, class_loader);
2106   }
2107 
2108   return klass;
2109 }
2110 
2111 
2112 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2113                                              Handle class_loader1,
2114                                              Handle class_loader2,
2115                                              Thread* THREAD) {
2116   ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2117   ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2118 
2119   Symbol* constraint_name = NULL;
2120   if (!FieldType::is_array(class_name)) {
2121     constraint_name = class_name;
2122   } else {
2123     // For array classes, their Klass*s are not kept in the
2124     // constraint table. The element classes are.
2125     FieldArrayInfo fd;
2126     BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2127     // primitive types always pass
2128     if (t != T_OBJECT) {
2129       return true;
2130     } else {
2131       constraint_name = fd.object_key();
2132     }
2133   }
2134   unsigned int d_hash1 = dictionary()->compute_hash(constraint_name, loader_data1);
2135   int d_index1 = dictionary()->hash_to_index(d_hash1);
2136 
2137   unsigned int d_hash2 = dictionary()->compute_hash(constraint_name, loader_data2);
2138   int d_index2 = dictionary()->hash_to_index(d_hash2);
2139   {
2140   MutexLocker mu_s(SystemDictionary_lock, THREAD);
2141 
2142   // Better never do a GC while we're holding these oops
2143   No_Safepoint_Verifier nosafepoint;
2144 
2145   Klass* klass1 = find_class(d_index1, d_hash1, constraint_name, loader_data1);
2146   Klass* klass2 = find_class(d_index2, d_hash2, constraint_name, loader_data2);
2147   return constraints()->add_entry(constraint_name, klass1, class_loader1,
2148                                   klass2, class_loader2);
2149   }
2150 }
2151 
2152 // Add entry to resolution error table to record the error when the first
2153 // attempt to resolve a reference to a class has failed.
2154 void SystemDictionary::add_resolution_error(constantPoolHandle pool, int which,
2155                                             Symbol* error, Symbol* message) {
2156   unsigned int hash = resolution_errors()->compute_hash(pool, which);
2157   int index = resolution_errors()->hash_to_index(hash);
2158   {
2159     MutexLocker ml(SystemDictionary_lock, Thread::current());
2160     resolution_errors()->add_entry(index, hash, pool, which, error, message);
2161   }
2162 }
2163 
2164 // Delete a resolution error for RedefineClasses for a constant pool is going away
2165 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2166   resolution_errors()->delete_entry(pool);
2167 }
2168 
2169 // Lookup resolution error table. Returns error if found, otherwise NULL.
2170 Symbol* SystemDictionary::find_resolution_error(constantPoolHandle pool, int which,
2171                                                 Symbol** message) {
2172   unsigned int hash = resolution_errors()->compute_hash(pool, which);
2173   int index = resolution_errors()->hash_to_index(hash);
2174   {
2175     MutexLocker ml(SystemDictionary_lock, Thread::current());
2176     ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2177     if (entry != NULL) {
2178       *message = entry->message();
2179       return entry->error();
2180     } else {
2181       return NULL;
2182     }
2183   }
2184 }
2185 
2186 
2187 // Signature constraints ensure that callers and callees agree about
2188 // the meaning of type names in their signatures.  This routine is the
2189 // intake for constraints.  It collects them from several places:
2190 //
2191 //  * LinkResolver::resolve_method (if check_access is true) requires
2192 //    that the resolving class (the caller) and the defining class of
2193 //    the resolved method (the callee) agree on each type in the
2194 //    method's signature.
2195 //
2196 //  * LinkResolver::resolve_interface_method performs exactly the same
2197 //    checks.
2198 //
2199 //  * LinkResolver::resolve_field requires that the constant pool
2200 //    attempting to link to a field agree with the field's defining
2201 //    class about the type of the field signature.
2202 //
2203 //  * klassVtable::initialize_vtable requires that, when a class
2204 //    overrides a vtable entry allocated by a superclass, that the
2205 //    overriding method (i.e., the callee) agree with the superclass
2206 //    on each type in the method's signature.
2207 //
2208 //  * klassItable::initialize_itable requires that, when a class fills
2209 //    in its itables, for each non-abstract method installed in an
2210 //    itable, the method (i.e., the callee) agree with the interface
2211 //    on each type in the method's signature.
2212 //
2213 // All those methods have a boolean (check_access, checkconstraints)
2214 // which turns off the checks.  This is used from specialized contexts
2215 // such as bootstrapping, dumping, and debugging.
2216 //
2217 // No direct constraint is placed between the class and its
2218 // supertypes.  Constraints are only placed along linked relations
2219 // between callers and callees.  When a method overrides or implements
2220 // an abstract method in a supertype (superclass or interface), the
2221 // constraints are placed as if the supertype were the caller to the
2222 // overriding method.  (This works well, since callers to the
2223 // supertype have already established agreement between themselves and
2224 // the supertype.)  As a result of all this, a class can disagree with
2225 // its supertype about the meaning of a type name, as long as that
2226 // class neither calls a relevant method of the supertype, nor is
2227 // called (perhaps via an override) from the supertype.
2228 //
2229 //
2230 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2231 //
2232 // Make sure all class components (including arrays) in the given
2233 // signature will be resolved to the same class in both loaders.
2234 // Returns the name of the type that failed a loader constraint check, or
2235 // NULL if no constraint failed.  No exception except OOME is thrown.
2236 // Arrays are not added to the loader constraint table, their elements are.
2237 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2238                                                Handle loader1, Handle loader2,
2239                                                bool is_method, TRAPS)  {
2240   // Nothing to do if loaders are the same.
2241   if (loader1() == loader2()) {
2242     return NULL;
2243   }
2244 
2245   SignatureStream sig_strm(signature, is_method);
2246   while (!sig_strm.is_done()) {
2247     if (sig_strm.is_object()) {
2248       Symbol* sig = sig_strm.as_symbol(CHECK_NULL);
2249       if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2250         return sig;
2251       }
2252     }
2253     sig_strm.next();
2254   }
2255   return NULL;
2256 }
2257 
2258 
2259 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2260                                                             Symbol* signature,
2261                                                             TRAPS) {
2262   methodHandle empty;
2263   assert(MethodHandles::is_signature_polymorphic(iid) &&
2264          MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2265          iid != vmIntrinsics::_invokeGeneric,
2266          err_msg("must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid)));
2267 
2268   unsigned int hash  = invoke_method_table()->compute_hash(signature, iid);
2269   int          index = invoke_method_table()->hash_to_index(hash);
2270   SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2271   methodHandle m;
2272   if (spe == NULL || spe->method() == NULL) {
2273     spe = NULL;
2274     // Must create lots of stuff here, but outside of the SystemDictionary lock.
2275     m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2276     if (!Arguments::is_interpreter_only()) {
2277       // Generate a compiled form of the MH intrinsic.
2278       AdapterHandlerLibrary::create_native_wrapper(m);
2279       // Check if have the compiled code.
2280       if (!m->has_compiled_code()) {
2281         THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(),
2282                    "out of space in CodeCache for method handle intrinsic", empty);
2283       }
2284     }
2285     // Now grab the lock.  We might have to throw away the new method,
2286     // if a racing thread has managed to install one at the same time.
2287     {
2288       MutexLocker ml(SystemDictionary_lock, THREAD);
2289       spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2290       if (spe == NULL)
2291         spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2292       if (spe->method() == NULL)
2293         spe->set_method(m());
2294     }
2295   }
2296 
2297   assert(spe != NULL && spe->method() != NULL, "");
2298   assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2299          spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2300          "MH intrinsic invariant");
2301   return spe->method();
2302 }
2303 
2304 // Helper for unpacking the return value from linkMethod and linkCallSite.
2305 static methodHandle unpack_method_and_appendix(Handle mname,
2306                                                KlassHandle accessing_klass,
2307                                                objArrayHandle appendix_box,
2308                                                Handle* appendix_result,
2309                                                TRAPS) {
2310   methodHandle empty;
2311   if (mname.not_null()) {
2312     Metadata* vmtarget = java_lang_invoke_MemberName::vmtarget(mname());
2313     if (vmtarget != NULL && vmtarget->is_method()) {
2314       Method* m = (Method*)vmtarget;
2315       oop appendix = appendix_box->obj_at(0);
2316       if (TraceMethodHandles) {
2317     #ifndef PRODUCT
2318         tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2319         m->print();
2320         if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2321         tty->cr();
2322     #endif //PRODUCT
2323       }
2324       (*appendix_result) = Handle(THREAD, appendix);
2325       // the target is stored in the cpCache and if a reference to this
2326       // MethodName is dropped we need a way to make sure the
2327       // class_loader containing this method is kept alive.
2328       // FIXME: the appendix might also preserve this dependency.
2329       ClassLoaderData* this_key = InstanceKlass::cast(accessing_klass())->class_loader_data();
2330       this_key->record_dependency(m->method_holder(), CHECK_NULL); // Can throw OOM
2331       return methodHandle(THREAD, m);
2332     }
2333   }
2334   THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2335   return empty;
2336 }
2337 
2338 methodHandle SystemDictionary::find_method_handle_invoker(Symbol* name,
2339                                                           Symbol* signature,
2340                                                           KlassHandle accessing_klass,
2341                                                           Handle *appendix_result,
2342                                                           Handle *method_type_result,
2343                                                           TRAPS) {
2344   methodHandle empty;
2345   assert(!THREAD->is_Compiler_thread(), "");
2346   Handle method_type =
2347     SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2348   if (false) {  // FIXME: Decide if the Java upcall should resolve signatures.
2349     method_type = java_lang_String::create_from_symbol(signature, CHECK_(empty));
2350   }
2351 
2352   KlassHandle  mh_klass = SystemDictionary::MethodHandle_klass();
2353   int ref_kind = JVM_REF_invokeVirtual;
2354   Handle name_str = StringTable::intern(name, CHECK_(empty));
2355   objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2356   assert(appendix_box->obj_at(0) == NULL, "");
2357 
2358   // This should not happen.  JDK code should take care of that.
2359   if (accessing_klass.is_null() || method_type.is_null()) {
2360     THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
2361   }
2362 
2363   // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2364   JavaCallArguments args;
2365   args.push_oop(accessing_klass()->java_mirror());
2366   args.push_int(ref_kind);
2367   args.push_oop(mh_klass()->java_mirror());
2368   args.push_oop(name_str());
2369   args.push_oop(method_type());
2370   args.push_oop(appendix_box());
2371   JavaValue result(T_OBJECT);
2372   JavaCalls::call_static(&result,
2373                          SystemDictionary::MethodHandleNatives_klass(),
2374                          vmSymbols::linkMethod_name(),
2375                          vmSymbols::linkMethod_signature(),
2376                          &args, CHECK_(empty));
2377   Handle mname(THREAD, (oop) result.get_jobject());
2378   (*method_type_result) = method_type;
2379   return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2380 }
2381 
2382 
2383 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2384 // signature, as interpreted relative to the given class loader.
2385 // Because of class loader constraints, all method handle usage must be
2386 // consistent with this loader.
2387 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2388                                                  KlassHandle accessing_klass,
2389                                                  TRAPS) {
2390   Handle empty;
2391   vmIntrinsics::ID null_iid = vmIntrinsics::_none;  // distinct from all method handle invoker intrinsics
2392   unsigned int hash  = invoke_method_table()->compute_hash(signature, null_iid);
2393   int          index = invoke_method_table()->hash_to_index(hash);
2394   SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2395   if (spe != NULL && spe->method_type() != NULL) {
2396     assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2397     return Handle(THREAD, spe->method_type());
2398   } else if (THREAD->is_Compiler_thread()) {
2399     warning("SystemDictionary::find_method_handle_type called from compiler thread");  // FIXME
2400     return Handle();  // do not attempt from within compiler, unless it was cached
2401   }
2402 
2403   Handle class_loader, protection_domain;
2404   bool is_on_bcp = true;  // keep this true as long as we can materialize from the boot classloader
2405   int npts = ArgumentCount(signature).size();
2406   objArrayHandle pts = oopFactory::new_objArray(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2407   int arg = 0;
2408   Handle rt;                            // the return type from the signature
2409   ResourceMark rm(THREAD);
2410   for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2411     oop mirror = NULL;
2412     if (is_on_bcp) {
2413       // Note:  class_loader & protection_domain are both null at this point.
2414       mirror = ss.as_java_mirror(class_loader, protection_domain,
2415                                  SignatureStream::ReturnNull, CHECK_(empty));
2416       if (mirror == NULL) {
2417         // fall back from BCP to accessing_klass
2418         if (accessing_klass.not_null()) {
2419           class_loader      = Handle(THREAD, InstanceKlass::cast(accessing_klass())->class_loader());
2420           protection_domain = Handle(THREAD, InstanceKlass::cast(accessing_klass())->protection_domain());
2421         }
2422         is_on_bcp = false;
2423       }
2424     }
2425     if (!is_on_bcp) {
2426       // Resolve, throwing a real error if it doesn't work.
2427       mirror = ss.as_java_mirror(class_loader, protection_domain,
2428                                  SignatureStream::NCDFError, CHECK_(empty));
2429     }
2430     if (ss.at_return_type())
2431       rt = Handle(THREAD, mirror);
2432     else
2433       pts->obj_at_put(arg++, mirror);
2434 
2435     // Check accessibility.
2436     if (ss.is_object() && accessing_klass.not_null()) {
2437       Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2438       mirror = NULL;  // safety
2439       // Emulate ConstantPool::verify_constant_pool_resolve.
2440       if (sel_klass->oop_is_objArray())
2441         sel_klass = ObjArrayKlass::cast(sel_klass)->bottom_klass();
2442       if (sel_klass->oop_is_instance()) {
2443         KlassHandle sel_kh(THREAD, sel_klass);
2444         LinkResolver::check_klass_accessability(accessing_klass, sel_kh, CHECK_(empty));
2445       }
2446     }
2447   }
2448   assert(arg == npts, "");
2449 
2450   // call java.lang.invoke.MethodHandleNatives::findMethodType(Class rt, Class[] pts) -> MethodType
2451   JavaCallArguments args(Handle(THREAD, rt()));
2452   args.push_oop(pts());
2453   JavaValue result(T_OBJECT);
2454   JavaCalls::call_static(&result,
2455                          SystemDictionary::MethodHandleNatives_klass(),
2456                          vmSymbols::findMethodHandleType_name(),
2457                          vmSymbols::findMethodHandleType_signature(),
2458                          &args, CHECK_(empty));
2459   Handle method_type(THREAD, (oop) result.get_jobject());
2460 
2461   if (is_on_bcp) {
2462     // We can cache this MethodType inside the JVM.
2463     MutexLocker ml(SystemDictionary_lock, THREAD);
2464     spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2465     if (spe == NULL)
2466       spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2467     if (spe->method_type() == NULL) {
2468       spe->set_method_type(method_type());
2469     }
2470   }
2471 
2472   // report back to the caller with the MethodType
2473   return method_type;
2474 }
2475 
2476 // Ask Java code to find or construct a method handle constant.
2477 Handle SystemDictionary::link_method_handle_constant(KlassHandle caller,
2478                                                      int ref_kind, //e.g., JVM_REF_invokeVirtual
2479                                                      KlassHandle callee,
2480                                                      Symbol* name_sym,
2481                                                      Symbol* signature,
2482                                                      TRAPS) {
2483   Handle empty;
2484   Handle name = java_lang_String::create_from_symbol(name_sym, CHECK_(empty));
2485   Handle type;
2486   if (signature->utf8_length() > 0 && signature->byte_at(0) == '(') {
2487     type = find_method_handle_type(signature, caller, CHECK_(empty));
2488   } else if (caller.is_null()) {
2489     // This should not happen.  JDK code should take care of that.
2490     THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2491   } else {
2492     ResourceMark rm(THREAD);
2493     SignatureStream ss(signature, false);
2494     if (!ss.is_done()) {
2495       oop mirror = ss.as_java_mirror(caller->class_loader(), caller->protection_domain(),
2496                                      SignatureStream::NCDFError, CHECK_(empty));
2497       type = Handle(THREAD, mirror);
2498       ss.next();
2499       if (!ss.is_done())  type = Handle();  // error!
2500     }
2501   }
2502   if (type.is_null()) {
2503     THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad signature", empty);
2504   }
2505 
2506   // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2507   JavaCallArguments args;
2508   args.push_oop(caller->java_mirror());  // the referring class
2509   args.push_int(ref_kind);
2510   args.push_oop(callee->java_mirror());  // the target class
2511   args.push_oop(name());
2512   args.push_oop(type());
2513   JavaValue result(T_OBJECT);
2514   JavaCalls::call_static(&result,
2515                          SystemDictionary::MethodHandleNatives_klass(),
2516                          vmSymbols::linkMethodHandleConstant_name(),
2517                          vmSymbols::linkMethodHandleConstant_signature(),
2518                          &args, CHECK_(empty));
2519   return Handle(THREAD, (oop) result.get_jobject());
2520 }
2521 
2522 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2523 // name and signature, as interpreted relative to the given class loader.
2524 methodHandle SystemDictionary::find_dynamic_call_site_invoker(KlassHandle caller,
2525                                                               Handle bootstrap_specifier,
2526                                                               Symbol* name,
2527                                                               Symbol* type,
2528                                                               Handle *appendix_result,
2529                                                               Handle *method_type_result,
2530                                                               TRAPS) {
2531   methodHandle empty;
2532   Handle bsm, info;
2533   if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2534     bsm = bootstrap_specifier;
2535   } else {
2536     assert(bootstrap_specifier->is_objArray(), "");
2537     objArrayHandle args(THREAD, (objArrayOop) bootstrap_specifier());
2538     int len = args->length();
2539     assert(len >= 1, "");
2540     bsm = Handle(THREAD, args->obj_at(0));
2541     if (len > 1) {
2542       objArrayOop args1 = oopFactory::new_objArray(SystemDictionary::Object_klass(), len-1, CHECK_(empty));
2543       for (int i = 1; i < len; i++)
2544         args1->obj_at_put(i-1, args->obj_at(i));
2545       info = Handle(THREAD, args1);
2546     }
2547   }
2548   guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2549             "caller must supply a valid BSM");
2550 
2551   Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2552   Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2553 
2554   // This should not happen.  JDK code should take care of that.
2555   if (caller.is_null() || method_type.is_null()) {
2556     THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty);
2557   }
2558 
2559   objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2560   assert(appendix_box->obj_at(0) == NULL, "");
2561 
2562   // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, bsm, name, mtype, info, &appendix)
2563   JavaCallArguments args;
2564   args.push_oop(caller->java_mirror());
2565   args.push_oop(bsm());
2566   args.push_oop(method_name());
2567   args.push_oop(method_type());
2568   args.push_oop(info());
2569   args.push_oop(appendix_box);
2570   JavaValue result(T_OBJECT);
2571   JavaCalls::call_static(&result,
2572                          SystemDictionary::MethodHandleNatives_klass(),
2573                          vmSymbols::linkCallSite_name(),
2574                          vmSymbols::linkCallSite_signature(),
2575                          &args, CHECK_(empty));
2576   Handle mname(THREAD, (oop) result.get_jobject());
2577   (*method_type_result) = method_type;
2578   return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
2579 }
2580 
2581 // Since the identity hash code for symbols changes when the symbols are
2582 // moved from the regular perm gen (hash in the mark word) to the shared
2583 // spaces (hash is the address), the classes loaded into the dictionary
2584 // may be in the wrong buckets.
2585 
2586 void SystemDictionary::reorder_dictionary() {
2587   dictionary()->reorder_dictionary();
2588 }
2589 
2590 
2591 void SystemDictionary::copy_buckets(char** top, char* end) {
2592   dictionary()->copy_buckets(top, end);
2593 }
2594 
2595 
2596 void SystemDictionary::copy_table(char** top, char* end) {
2597   dictionary()->copy_table(top, end);
2598 }
2599 
2600 
2601 void SystemDictionary::reverse() {
2602   dictionary()->reverse();
2603 }
2604 
2605 int SystemDictionary::number_of_classes() {
2606   return dictionary()->number_of_entries();
2607 }
2608 
2609 
2610 // ----------------------------------------------------------------------------
2611 void SystemDictionary::print_shared(bool details) {
2612   shared_dictionary()->print(details);
2613 }
2614 
2615 void SystemDictionary::print(bool details) {
2616   dictionary()->print(details);
2617 
2618   // Placeholders
2619   GCMutexLocker mu(SystemDictionary_lock);
2620   placeholders()->print();
2621 
2622   // loader constraints - print under SD_lock
2623   constraints()->print();
2624 }
2625 
2626 
2627 void SystemDictionary::verify() {
2628   guarantee(dictionary() != NULL, "Verify of system dictionary failed");
2629   guarantee(constraints() != NULL,
2630             "Verify of loader constraints failed");
2631   guarantee(dictionary()->number_of_entries() >= 0 &&
2632             placeholders()->number_of_entries() >= 0,
2633             "Verify of system dictionary failed");
2634 
2635   // Verify dictionary
2636   dictionary()->verify();
2637 
2638   GCMutexLocker mu(SystemDictionary_lock);
2639   placeholders()->verify();
2640 
2641   // Verify constraint table
2642   guarantee(constraints() != NULL, "Verify of loader constraints failed");
2643   constraints()->verify(dictionary(), placeholders());
2644 }
2645 
2646 // utility function for class load event
2647 void SystemDictionary::post_class_load_event(const Ticks& start_time,
2648                                              instanceKlassHandle k,
2649                                              Handle initiating_loader) {
2650 #if INCLUDE_TRACE
2651   EventClassLoad event(UNTIMED);
2652   if (event.should_commit()) {
2653     event.set_starttime(start_time);
2654     event.set_loadedClass(k());
2655     oop defining_class_loader = k->class_loader();
2656     event.set_definingClassLoader(defining_class_loader !=  NULL ?
2657                                     defining_class_loader->klass() : (Klass*)NULL);
2658     oop class_loader = initiating_loader.is_null() ? (oop)NULL : initiating_loader();
2659     event.set_initiatingClassLoader(class_loader != NULL ?
2660                                       class_loader->klass() : (Klass*)NULL);
2661     event.commit();
2662   }
2663 #endif // INCLUDE_TRACE
2664 }
2665 
2666 #ifndef PRODUCT
2667 
2668 // statistics code
2669 class ClassStatistics: AllStatic {
2670  private:
2671   static int nclasses;        // number of classes
2672   static int nmethods;        // number of methods
2673   static int nmethoddata;     // number of methodData
2674   static int class_size;      // size of class objects in words
2675   static int method_size;     // size of method objects in words
2676   static int debug_size;      // size of debug info in methods
2677   static int methoddata_size; // size of methodData objects in words
2678 
2679   static void do_class(Klass* k) {
2680     nclasses++;
2681     class_size += k->size();
2682     if (k->oop_is_instance()) {
2683       InstanceKlass* ik = (InstanceKlass*)k;
2684       class_size += ik->methods()->size();
2685       class_size += ik->constants()->size();
2686       class_size += ik->local_interfaces()->size();
2687       class_size += ik->transitive_interfaces()->size();
2688       // We do not have to count implementors, since we only store one!
2689       // SSS: How should these be accounted now that they have moved?
2690       // class_size += ik->fields()->length();
2691     }
2692   }
2693 
2694   static void do_method(Method* m) {
2695     nmethods++;
2696     method_size += m->size();
2697     // class loader uses same objArray for empty vectors, so don't count these
2698     if (m->has_stackmap_table()) {
2699       method_size += m->stackmap_data()->size();
2700     }
2701 
2702     MethodData* mdo = m->method_data();
2703     if (mdo != NULL) {
2704       nmethoddata++;
2705       methoddata_size += mdo->size();
2706     }
2707   }
2708 
2709  public:
2710   static void print() {
2711     SystemDictionary::classes_do(do_class);
2712     SystemDictionary::methods_do(do_method);
2713     tty->print_cr("Class statistics:");
2714     tty->print_cr("%d classes (%d bytes)", nclasses, class_size * oopSize);
2715     tty->print_cr("%d methods (%d bytes = %d base + %d debug info)", nmethods,
2716                   (method_size + debug_size) * oopSize, method_size * oopSize, debug_size * oopSize);
2717     tty->print_cr("%d methoddata (%d bytes)", nmethoddata, methoddata_size * oopSize);
2718   }
2719 };
2720 
2721 
2722 int ClassStatistics::nclasses        = 0;
2723 int ClassStatistics::nmethods        = 0;
2724 int ClassStatistics::nmethoddata     = 0;
2725 int ClassStatistics::class_size      = 0;
2726 int ClassStatistics::method_size     = 0;
2727 int ClassStatistics::debug_size      = 0;
2728 int ClassStatistics::methoddata_size = 0;
2729 
2730 void SystemDictionary::print_class_statistics() {
2731   ResourceMark rm;
2732   ClassStatistics::print();
2733 }
2734 
2735 
2736 class MethodStatistics: AllStatic {
2737  public:
2738   enum {
2739     max_parameter_size = 10
2740   };
2741  private:
2742 
2743   static int _number_of_methods;
2744   static int _number_of_final_methods;
2745   static int _number_of_static_methods;
2746   static int _number_of_native_methods;
2747   static int _number_of_synchronized_methods;
2748   static int _number_of_profiled_methods;
2749   static int _number_of_bytecodes;
2750   static int _parameter_size_profile[max_parameter_size];
2751   static int _bytecodes_profile[Bytecodes::number_of_java_codes];
2752 
2753   static void initialize() {
2754     _number_of_methods        = 0;
2755     _number_of_final_methods  = 0;
2756     _number_of_static_methods = 0;
2757     _number_of_native_methods = 0;
2758     _number_of_synchronized_methods = 0;
2759     _number_of_profiled_methods = 0;
2760     _number_of_bytecodes      = 0;
2761     for (int i = 0; i < max_parameter_size             ; i++) _parameter_size_profile[i] = 0;
2762     for (int j = 0; j < Bytecodes::number_of_java_codes; j++) _bytecodes_profile     [j] = 0;
2763   };
2764 
2765   static void do_method(Method* m) {
2766     _number_of_methods++;
2767     // collect flag info
2768     if (m->is_final()       ) _number_of_final_methods++;
2769     if (m->is_static()      ) _number_of_static_methods++;
2770     if (m->is_native()      ) _number_of_native_methods++;
2771     if (m->is_synchronized()) _number_of_synchronized_methods++;
2772     if (m->method_data() != NULL) _number_of_profiled_methods++;
2773     // collect parameter size info (add one for receiver, if any)
2774     _parameter_size_profile[MIN2(m->size_of_parameters() + (m->is_static() ? 0 : 1), max_parameter_size - 1)]++;
2775     // collect bytecodes info
2776     {
2777       Thread *thread = Thread::current();
2778       HandleMark hm(thread);
2779       BytecodeStream s(methodHandle(thread, m));
2780       Bytecodes::Code c;
2781       while ((c = s.next()) >= 0) {
2782         _number_of_bytecodes++;
2783         _bytecodes_profile[c]++;
2784       }
2785     }
2786   }
2787 
2788  public:
2789   static void print() {
2790     initialize();
2791     SystemDictionary::methods_do(do_method);
2792     // generate output
2793     tty->cr();
2794     tty->print_cr("Method statistics (static):");
2795     // flag distribution
2796     tty->cr();
2797     tty->print_cr("%6d final        methods  %6.1f%%", _number_of_final_methods       , _number_of_final_methods        * 100.0F / _number_of_methods);
2798     tty->print_cr("%6d static       methods  %6.1f%%", _number_of_static_methods      , _number_of_static_methods       * 100.0F / _number_of_methods);
2799     tty->print_cr("%6d native       methods  %6.1f%%", _number_of_native_methods      , _number_of_native_methods       * 100.0F / _number_of_methods);
2800     tty->print_cr("%6d synchronized methods  %6.1f%%", _number_of_synchronized_methods, _number_of_synchronized_methods * 100.0F / _number_of_methods);
2801     tty->print_cr("%6d profiled     methods  %6.1f%%", _number_of_profiled_methods, _number_of_profiled_methods * 100.0F / _number_of_methods);
2802     // parameter size profile
2803     tty->cr();
2804     { int tot = 0;
2805       int avg = 0;
2806       for (int i = 0; i < max_parameter_size; i++) {
2807         int n = _parameter_size_profile[i];
2808         tot += n;
2809         avg += n*i;
2810         tty->print_cr("parameter size = %1d: %6d methods  %5.1f%%", i, n, n * 100.0F / _number_of_methods);
2811       }
2812       assert(tot == _number_of_methods, "should be the same");
2813       tty->print_cr("                    %6d methods  100.0%%", _number_of_methods);
2814       tty->print_cr("(average parameter size = %3.1f including receiver, if any)", (float)avg / _number_of_methods);
2815     }
2816     // bytecodes profile
2817     tty->cr();
2818     { int tot = 0;
2819       for (int i = 0; i < Bytecodes::number_of_java_codes; i++) {
2820         if (Bytecodes::is_defined(i)) {
2821           Bytecodes::Code c = Bytecodes::cast(i);
2822           int n = _bytecodes_profile[c];
2823           tot += n;
2824           tty->print_cr("%9d  %7.3f%%  %s", n, n * 100.0F / _number_of_bytecodes, Bytecodes::name(c));
2825         }
2826       }
2827       assert(tot == _number_of_bytecodes, "should be the same");
2828       tty->print_cr("%9d  100.000%%", _number_of_bytecodes);
2829     }
2830     tty->cr();
2831   }
2832 };
2833 
2834 int MethodStatistics::_number_of_methods;
2835 int MethodStatistics::_number_of_final_methods;
2836 int MethodStatistics::_number_of_static_methods;
2837 int MethodStatistics::_number_of_native_methods;
2838 int MethodStatistics::_number_of_synchronized_methods;
2839 int MethodStatistics::_number_of_profiled_methods;
2840 int MethodStatistics::_number_of_bytecodes;
2841 int MethodStatistics::_parameter_size_profile[MethodStatistics::max_parameter_size];
2842 int MethodStatistics::_bytecodes_profile[Bytecodes::number_of_java_codes];
2843 
2844 
2845 void SystemDictionary::print_method_statistics() {
2846   MethodStatistics::print();
2847 }
2848 
2849 #endif // PRODUCT
--- EOF ---