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systemDictionary.cpp 115.1 KB
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/*
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 * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
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 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
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 *
 */

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#include "precompiled.hpp"
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#include "classfile/classLoaderData.inline.hpp"
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#include "classfile/dictionary.hpp"
#include "classfile/javaClasses.hpp"
#include "classfile/loaderConstraints.hpp"
#include "classfile/placeholders.hpp"
#include "classfile/resolutionErrors.hpp"
#include "classfile/systemDictionary.hpp"
#include "classfile/vmSymbols.hpp"
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#include "compiler/compileBroker.hpp"
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#include "interpreter/bytecodeStream.hpp"
#include "interpreter/interpreter.hpp"
#include "memory/gcLocker.hpp"
#include "memory/oopFactory.hpp"
#include "oops/instanceKlass.hpp"
#include "oops/instanceRefKlass.hpp"
#include "oops/klass.inline.hpp"
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#include "oops/methodData.hpp"
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#include "oops/objArrayKlass.hpp"
#include "oops/oop.inline.hpp"
#include "oops/oop.inline2.hpp"
#include "oops/typeArrayKlass.hpp"
#include "prims/jvmtiEnvBase.hpp"
#include "prims/methodHandles.hpp"
#include "runtime/biasedLocking.hpp"
#include "runtime/fieldType.hpp"
#include "runtime/handles.inline.hpp"
#include "runtime/java.hpp"
#include "runtime/javaCalls.hpp"
#include "runtime/mutexLocker.hpp"
#include "runtime/signature.hpp"
#include "services/classLoadingService.hpp"
#include "services/threadService.hpp"
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Dictionary*            SystemDictionary::_dictionary          = NULL;
PlaceholderTable*      SystemDictionary::_placeholders        = NULL;
Dictionary*            SystemDictionary::_shared_dictionary   = NULL;
LoaderConstraintTable* SystemDictionary::_loader_constraints  = NULL;
ResolutionErrorTable*  SystemDictionary::_resolution_errors   = NULL;
SymbolPropertyTable*   SystemDictionary::_invoke_method_table = NULL;
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int         SystemDictionary::_number_of_modifications = 0;
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int         SystemDictionary::_sdgeneration               = 0;
const int   SystemDictionary::_primelist[_prime_array_size] = {1009,2017,4049,5051,10103,
              20201,40423,99991};
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oop         SystemDictionary::_system_loader_lock_obj     =  NULL;

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Klass*      SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
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                                                          =  { NULL /*, NULL...*/ };

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Klass*      SystemDictionary::_box_klasses[T_VOID+1]      =  { NULL /*, NULL...*/ };
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oop         SystemDictionary::_java_system_loader         =  NULL;

bool        SystemDictionary::_has_loadClassInternal      =  false;
bool        SystemDictionary::_has_checkPackageAccess     =  false;

// lazily initialized klass variables
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Klass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
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// ----------------------------------------------------------------------------
// Java-level SystemLoader

oop SystemDictionary::java_system_loader() {
  return _java_system_loader;
}

void SystemDictionary::compute_java_system_loader(TRAPS) {
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  KlassHandle system_klass(THREAD, WK_KLASS(ClassLoader_klass));
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  JavaValue result(T_OBJECT);
  JavaCalls::call_static(&result,
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                         KlassHandle(THREAD, WK_KLASS(ClassLoader_klass)),
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                         vmSymbols::getSystemClassLoader_name(),
                         vmSymbols::void_classloader_signature(),
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                         CHECK);

  _java_system_loader = (oop)result.get_jobject();
}


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ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, TRAPS) {
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  if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
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  return ClassLoaderDataGraph::find_or_create(class_loader, CHECK_NULL);
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}

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// ----------------------------------------------------------------------------
// debugging

#ifdef ASSERT

// return true if class_name contains no '.' (internal format is '/')
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bool SystemDictionary::is_internal_format(Symbol* class_name) {
  if (class_name != NULL) {
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    ResourceMark rm;
    char* name = class_name->as_C_string();
    return strchr(name, '.') == NULL;
  } else {
    return true;
  }
}

#endif

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// ----------------------------------------------------------------------------
// Parallel class loading check

bool SystemDictionary::is_parallelCapable(Handle class_loader) {
  if (UnsyncloadClass || class_loader.is_null()) return true;
  if (AlwaysLockClassLoader) return false;
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  return java_lang_ClassLoader::parallelCapable(class_loader());
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}
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// ----------------------------------------------------------------------------
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// ParallelDefineClass flag does not apply to bootclass loader
bool SystemDictionary::is_parallelDefine(Handle class_loader) {
   if (class_loader.is_null()) return false;
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   if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
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     return true;
   }
   return false;
}
// ----------------------------------------------------------------------------
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// Resolving of classes

// Forwards to resolve_or_null

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Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
  Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
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  if (HAS_PENDING_EXCEPTION || klass == NULL) {
    KlassHandle k_h(THREAD, klass);
    // can return a null klass
    klass = handle_resolution_exception(class_name, class_loader, protection_domain, throw_error, k_h, THREAD);
  }
  return klass;
}

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Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, KlassHandle klass_h, TRAPS) {
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  if (HAS_PENDING_EXCEPTION) {
    // If we have a pending exception we forward it to the caller, unless throw_error is true,
    // in which case we have to check whether the pending exception is a ClassNotFoundException,
    // and if so convert it to a NoClassDefFoundError
    // And chain the original ClassNotFoundException
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    if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
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      ResourceMark rm(THREAD);
      assert(klass_h() == NULL, "Should not have result with exception pending");
      Handle e(THREAD, PENDING_EXCEPTION);
      CLEAR_PENDING_EXCEPTION;
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      THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
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    } else {
      return NULL;
    }
  }
  // Class not found, throw appropriate error or exception depending on value of throw_error
  if (klass_h() == NULL) {
    ResourceMark rm(THREAD);
    if (throw_error) {
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      THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
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    } else {
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      THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
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    }
  }
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  return (Klass*)klass_h();
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}


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Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
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                                           bool throw_error, TRAPS)
{
  return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
}


// Forwards to resolve_instance_class_or_null

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Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
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  assert(!THREAD->is_Compiler_thread(),
         err_msg("can not load classes with compiler thread: class=%s, classloader=%s",
                 class_name->as_C_string(),
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                 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string()));
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  if (FieldType::is_array(class_name)) {
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    return resolve_array_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
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  } else if (FieldType::is_obj(class_name)) {
    ResourceMark rm(THREAD);
    // Ignore wrapping L and ;.
    TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
                                   class_name->utf8_length() - 2, CHECK_NULL);
    return resolve_instance_class_or_null(name, class_loader, protection_domain, CHECK_NULL);
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  } else {
    return resolve_instance_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
  }
}

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Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
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  return resolve_or_null(class_name, Handle(), Handle(), THREAD);
}

// Forwards to resolve_instance_class_or_null

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Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
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                                                       Handle class_loader,
                                                       Handle protection_domain,
                                                       TRAPS) {
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  assert(FieldType::is_array(class_name), "must be array");
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  Klass* k = NULL;
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  FieldArrayInfo fd;
  // dimension and object_key in FieldArrayInfo are assigned as a side-effect
  // of this call
  BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
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  if (t == T_OBJECT) {
    // naked oop "k" is OK here -- we assign back into it
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    k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
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                                                         class_loader,
                                                         protection_domain,
                                                         CHECK_NULL);
    if (k != NULL) {
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      k = k->array_klass(fd.dimension(), CHECK_NULL);
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    }
  } else {
    k = Universe::typeArrayKlassObj(t);
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    k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
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  }
  return k;
}


// Must be called for any super-class or super-interface resolution
// during class definition to allow class circularity checking
// super-interface callers:
//    parse_interfaces - for defineClass & jvmtiRedefineClasses
// super-class callers:
//   ClassFileParser - for defineClass & jvmtiRedefineClasses
//   load_shared_class - while loading a class from shared archive
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//   resolve_instance_class_or_null:
//     via: handle_parallel_super_load
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//      when resolving a class that has an existing placeholder with
//      a saved superclass [i.e. a defineClass is currently in progress]
//      if another thread is trying to resolve the class, it must do
//      super-class checks on its own thread to catch class circularity
// This last call is critical in class circularity checking for cases
// where classloading is delegated to different threads and the
// classloader lock is released.
// Take the case: Base->Super->Base
//   1. If thread T1 tries to do a defineClass of class Base
//    resolve_super_or_fail creates placeholder: T1, Base (super Super)
//   2. resolve_instance_class_or_null does not find SD or placeholder for Super
//    so it tries to load Super
//   3. If we load the class internally, or user classloader uses same thread
//      loadClassFromxxx or defineClass via parseClassFile Super ...
//      3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
//      3.3 resolve_instance_class_or_null Base, finds placeholder for Base
//      3.4 calls resolve_super_or_fail Base
//      3.5 finds T1,Base -> throws class circularity
//OR 4. If T2 tries to resolve Super via defineClass Super ...
//      4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
//      4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
//      4.3 calls resolve_super_or_fail Super in parallel on own thread T2
//      4.4 finds T2, Super -> throws class circularity
// Must be called, even if superclass is null, since this is
// where the placeholder entry is created which claims this
// thread is loading this class/classloader.
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Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
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                                                 Symbol* class_name,
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                                                 Handle class_loader,
                                                 Handle protection_domain,
                                                 bool is_superclass,
                                                 TRAPS) {
  // Double-check, if child class is already loaded, just return super-class,interface
  // Don't add a placedholder if already loaded, i.e. already in system dictionary
  // Make sure there's a placeholder for the *child* before resolving.
  // Used as a claim that this thread is currently loading superclass/classloader
  // Used here for ClassCircularity checks and also for heap verification
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  // (every InstanceKlass in the heap needs to be in the system dictionary
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  // or have a placeholder).
  // Must check ClassCircularity before checking if super class is already loaded
  //
  // We might not already have a placeholder if this child_name was
  // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
  // the name of the class might not be known until the stream is actually
  // parsed.
  // Bugs 4643874, 4715493
  // compute_hash can have a safepoint

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  ClassLoaderData* loader_data = class_loader_data(class_loader);
  unsigned int d_hash = dictionary()->compute_hash(child_name, loader_data);
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  int d_index = dictionary()->hash_to_index(d_hash);
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  unsigned int p_hash = placeholders()->compute_hash(child_name, loader_data);
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  int p_index = placeholders()->hash_to_index(p_hash);
  // can't throw error holding a lock
  bool child_already_loaded = false;
  bool throw_circularity_error = false;
  {
    MutexLocker mu(SystemDictionary_lock, THREAD);
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    Klass* childk = find_class(d_index, d_hash, child_name, loader_data);
    Klass* quicksuperk;
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    // to support // loading: if child done loading, just return superclass
    // if class_name, & class_loader don't match:
    // if initial define, SD update will give LinkageError
    // if redefine: compare_class_versions will give HIERARCHY_CHANGED
    // so we don't throw an exception here.
    // see: nsk redefclass014 & java.lang.instrument Instrument032
    if ((childk != NULL ) && (is_superclass) &&
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       ((quicksuperk = InstanceKlass::cast(childk)->super()) != NULL) &&
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         ((quicksuperk->name() == class_name) &&
            (quicksuperk->class_loader()  == class_loader()))) {
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           return quicksuperk;
    } else {
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      PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
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      if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
          throw_circularity_error = true;
      }
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    }
    if (!throw_circularity_error) {
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      PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
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    }
  }
  if (throw_circularity_error) {
      ResourceMark rm(THREAD);
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      THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
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  }

// java.lang.Object should have been found above
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  assert(class_name != NULL, "null super class for resolving");
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  // Resolve the super class or interface, check results on return
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  Klass* superk = SystemDictionary::resolve_or_null(class_name,
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                                                 class_loader,
                                                 protection_domain,
                                                 THREAD);

  KlassHandle superk_h(THREAD, superk);

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  // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
  // It is no longer necessary to keep the placeholder table alive until update_dictionary
  // or error. GC used to walk the placeholder table as strong roots.
  // The instanceKlass is kept alive because the class loader is on the stack,
  // which keeps the loader_data alive, as well as all instanceKlasses in
  // the loader_data. parseClassFile adds the instanceKlass to loader_data.
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  {
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    MutexLocker mu(SystemDictionary_lock, THREAD);
    placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
    SystemDictionary_lock->notify_all();
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  }
  if (HAS_PENDING_EXCEPTION || superk_h() == NULL) {
    // can null superk
    superk_h = KlassHandle(THREAD, handle_resolution_exception(class_name, class_loader, protection_domain, true, superk_h, THREAD));
  }

  return superk_h();
}

void SystemDictionary::validate_protection_domain(instanceKlassHandle klass,
                                                  Handle class_loader,
                                                  Handle protection_domain,
                                                  TRAPS) {
  if(!has_checkPackageAccess()) return;

  // Now we have to call back to java to check if the initating class has access
  JavaValue result(T_VOID);
  if (TraceProtectionDomainVerification) {
    // Print out trace information
    tty->print_cr("Checking package access");
    tty->print(" - class loader:      "); class_loader()->print_value_on(tty);      tty->cr();
    tty->print(" - protection domain: "); protection_domain()->print_value_on(tty); tty->cr();
    tty->print(" - loading:           "); klass()->print_value_on(tty);             tty->cr();
  }

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  KlassHandle system_loader(THREAD, SystemDictionary::ClassLoader_klass());
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  JavaCalls::call_special(&result,
                         class_loader,
                         system_loader,
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                         vmSymbols::checkPackageAccess_name(),
                         vmSymbols::class_protectiondomain_signature(),
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                         Handle(THREAD, klass->java_mirror()),
                         protection_domain,
                         THREAD);

  if (TraceProtectionDomainVerification) {
    if (HAS_PENDING_EXCEPTION) {
      tty->print_cr(" -> DENIED !!!!!!!!!!!!!!!!!!!!!");
    } else {
     tty->print_cr(" -> granted");
    }
    tty->cr();
  }

  if (HAS_PENDING_EXCEPTION) return;

  // If no exception has been thrown, we have validated the protection domain
  // Insert the protection domain of the initiating class into the set.
  {
    // We recalculate the entry here -- we've called out to java since
    // the last time it was calculated.
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    ClassLoaderData* loader_data = class_loader_data(class_loader);

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    Symbol*  kn = klass->name();
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    unsigned int d_hash = dictionary()->compute_hash(kn, loader_data);
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    int d_index = dictionary()->hash_to_index(d_hash);

    MutexLocker mu(SystemDictionary_lock, THREAD);
    {
      // Note that we have an entry, and entries can be deleted only during GC,
      // so we cannot allow GC to occur while we're holding this entry.

      // We're using a No_Safepoint_Verifier to catch any place where we
      // might potentially do a GC at all.
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      // Dictionary::do_unloading() asserts that classes in SD are only
      // unloaded at a safepoint. Anonymous classes are not in SD.
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      No_Safepoint_Verifier nosafepoint;
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      dictionary()->add_protection_domain(d_index, d_hash, klass, loader_data,
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                                          protection_domain, THREAD);
    }
  }
}

// We only get here if this thread finds that another thread
// has already claimed the placeholder token for the current operation,
// but that other thread either never owned or gave up the
// object lock
// Waits on SystemDictionary_lock to indicate placeholder table updated
// On return, caller must recheck placeholder table state
//
// We only get here if
//  1) custom classLoader, i.e. not bootstrap classloader
//  2) UnsyncloadClass not set
//  3) custom classLoader has broken the class loader objectLock
//     so another thread got here in parallel
//
// lockObject must be held.
// Complicated dance due to lock ordering:
// Must first release the classloader object lock to
// allow initial definer to complete the class definition
// and to avoid deadlock
// Reclaim classloader lock object with same original recursion count
// Must release SystemDictionary_lock after notify, since
// class loader lock must be claimed before SystemDictionary_lock
// to prevent deadlocks
//
// The notify allows applications that did an untimed wait() on
// the classloader object lock to not hang.
void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
  assert_lock_strong(SystemDictionary_lock);

  bool calledholdinglock
      = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
  assert(calledholdinglock,"must hold lock for notify");
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  assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
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  ObjectSynchronizer::notifyall(lockObject, THREAD);
  intptr_t recursions =  ObjectSynchronizer::complete_exit(lockObject, THREAD);
  SystemDictionary_lock->wait();
  SystemDictionary_lock->unlock();
  ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
  SystemDictionary_lock->lock();
}

// If the class in is in the placeholder table, class loading is in progress
// For cases where the application changes threads to load classes, it
// is critical to ClassCircularity detection that we try loading
// the superclass on the same thread internally, so we do parallel
// super class loading here.
// This also is critical in cases where the original thread gets stalled
// even in non-circularity situations.
// Note: must call resolve_super_or_fail even if null super -
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// to force placeholder entry creation for this class for circularity detection
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// Caller must check for pending exception
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// Returns non-null Klass* if other thread has completed load
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// and we are done,
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// If return null Klass* and no pending exception, the caller must load the class
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instanceKlassHandle SystemDictionary::handle_parallel_super_load(
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    Symbol* name, Symbol* superclassname, Handle class_loader,
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    Handle protection_domain, Handle lockObject, TRAPS) {

  instanceKlassHandle nh = instanceKlassHandle(); // null Handle
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  ClassLoaderData* loader_data = class_loader_data(class_loader);
  unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
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  int d_index = dictionary()->hash_to_index(d_hash);
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  unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
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  int p_index = placeholders()->hash_to_index(p_hash);

  // superk is not used, resolve_super called for circularity check only
  // This code is reached in two situations. One if this thread
  // is loading the same class twice (e.g. ClassCircularity, or
  // java.lang.instrument).
  // The second is if another thread started the resolve_super first
  // and has not yet finished.
  // In both cases the original caller will clean up the placeholder
  // entry on error.
514
  Klass* superk = SystemDictionary::resolve_super_or_fail(name,
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                                                          superclassname,
                                                          class_loader,
                                                          protection_domain,
                                                          true,
                                                          CHECK_(nh));

521 522 523
  // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
  // Serial class loaders and bootstrap classloader do wait for superclass loads
 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
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    MutexLocker mu(SystemDictionary_lock, THREAD);
    // Check if classloading completed while we were loading superclass or waiting
526
    Klass* check = find_class(d_index, d_hash, name, loader_data);
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    if (check != NULL) {
      // Klass is already loaded, so just return it
      return(instanceKlassHandle(THREAD, check));
    } else {
      return nh;
    }
  }

  // must loop to both handle other placeholder updates
  // and spurious notifications
  bool super_load_in_progress = true;
  PlaceholderEntry* placeholder;
  while (super_load_in_progress) {
    MutexLocker mu(SystemDictionary_lock, THREAD);
    // Check if classloading completed while we were loading superclass or waiting
542
    Klass* check = find_class(d_index, d_hash, name, loader_data);
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    if (check != NULL) {
      // Klass is already loaded, so just return it
      return(instanceKlassHandle(THREAD, check));
    } else {
547
      placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
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      if (placeholder && placeholder->super_load_in_progress() ){
        // Before UnsyncloadClass:
        // We only get here if the application has released the
        // classloader lock when another thread was in the middle of loading a
        // superclass/superinterface for this class, and now
        // this thread is also trying to load this class.
        // To minimize surprises, the first thread that started to
        // load a class should be the one to complete the loading
        // with the classfile it initially expected.
        // This logic has the current thread wait once it has done
        // all the superclass/superinterface loading it can, until
        // the original thread completes the class loading or fails
560
        // If it completes we will use the resulting InstanceKlass
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        // which we will find below in the systemDictionary.
        // We also get here for parallel bootstrap classloader
        if (class_loader.is_null()) {
          SystemDictionary_lock->wait();
        } else {
          double_lock_wait(lockObject, THREAD);
        }
      } else {
        // If not in SD and not in PH, other thread's load must have failed
        super_load_in_progress = false;
      }
    }
  }
  return (nh);
}


578
Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name, Handle class_loader, Handle protection_domain, TRAPS) {
579 580
  assert(name != NULL && !FieldType::is_array(name) &&
         !FieldType::is_obj(name), "invalid class name");
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  // UseNewReflection
  // Fix for 4474172; see evaluation for more details
  class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
585
  ClassLoaderData *loader_data = register_loader(class_loader, CHECK_NULL);
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  // Do lookup to see if class already exist and the protection domain
  // has the right access
589 590 591 592
  // This call uses find which checks protection domain already matches
  // All subsequent calls use find_class, and set has_loaded_class so that
  // before we return a result we call out to java to check for valid protection domain
  // to allow returning the Klass* and add it to the pd_set if it is valid
593
  unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
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  int d_index = dictionary()->hash_to_index(d_hash);
595
  Klass* probe = dictionary()->find(d_index, d_hash, name, loader_data,
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                                      protection_domain, THREAD);
  if (probe != NULL) return probe;


  // Non-bootstrap class loaders will call out to class loader and
  // define via jvm/jni_DefineClass which will acquire the
  // class loader object lock to protect against multiple threads
  // defining the class in parallel by accident.
  // This lock must be acquired here so the waiter will find
  // any successful result in the SystemDictionary and not attempt
  // the define
607
  // ParallelCapable Classloaders and the bootstrap classloader,
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  // or all classloaders with UnsyncloadClass do not acquire lock here
  bool DoObjectLock = true;
610
  if (is_parallelCapable(class_loader)) {
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    DoObjectLock = false;
  }

614
  unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
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  int p_index = placeholders()->hash_to_index(p_hash);

  // Class is not in SystemDictionary so we have to do loading.
  // Make sure we are synchronized on the class loader before we proceed
  Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
  check_loader_lock_contention(lockObject, THREAD);
  ObjectLocker ol(lockObject, THREAD, DoObjectLock);

  // Check again (after locking) if class already exist in SystemDictionary
  bool class_has_been_loaded   = false;
  bool super_load_in_progress  = false;
  bool havesupername = false;
  instanceKlassHandle k;
  PlaceholderEntry* placeholder;
629
  Symbol* superclassname = NULL;
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  {
    MutexLocker mu(SystemDictionary_lock, THREAD);
633
    Klass* check = find_class(d_index, d_hash, name, loader_data);
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    if (check != NULL) {
      // Klass is already loaded, so just return it
      class_has_been_loaded = true;
      k = instanceKlassHandle(THREAD, check);
    } else {
639
      placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
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      if (placeholder && placeholder->super_load_in_progress()) {
         super_load_in_progress = true;
         if (placeholder->havesupername() == true) {
643
           superclassname = placeholder->supername();
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           havesupername = true;
         }
      }
    }
  }

650
  // If the class is in the placeholder table, class loading is in progress
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  if (super_load_in_progress && havesupername==true) {
    k = SystemDictionary::handle_parallel_super_load(name, superclassname,
        class_loader, protection_domain, lockObject, THREAD);
    if (HAS_PENDING_EXCEPTION) {
      return NULL;
    }
    if (!k.is_null()) {
      class_has_been_loaded = true;
    }
  }

662
  bool throw_circularity_error = false;
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  if (!class_has_been_loaded) {
664
    bool load_instance_added = false;
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    // add placeholder entry to record loading instance class
    // Five cases:
    // All cases need to prevent modifying bootclasssearchpath
    // in parallel with a classload of same classname
670 671 672
    // Redefineclasses uses existence of the placeholder for the duration
    // of the class load to prevent concurrent redefinition of not completely
    // defined classes.
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    // case 1. traditional classloaders that rely on the classloader object lock
    //   - no other need for LOAD_INSTANCE
    // case 2. traditional classloaders that break the classloader object lock
    //    as a deadlock workaround. Detection of this case requires that
    //    this check is done while holding the classloader object lock,
    //    and that lock is still held when calling classloader's loadClass.
    //    For these classloaders, we ensure that the first requestor
    //    completes the load and other requestors wait for completion.
    // case 3. UnsyncloadClass - don't use objectLocker
    //    With this flag, we allow parallel classloading of a
    //    class/classloader pair
    // case4. Bootstrap classloader - don't own objectLocker
    //    This classloader supports parallelism at the classloader level,
    //    but only allows a single load of a class/classloader pair.
    //    No performance benefit and no deadlock issues.
688 689
    // case 5. parallelCapable user level classloaders - without objectLocker
    //    Allow parallel classloading of a class/classloader pair
690

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    {
      MutexLocker mu(SystemDictionary_lock, THREAD);
693
      if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
694
        PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
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        if (oldprobe) {
          // only need check_seen_thread once, not on each loop
          // 6341374 java/lang/Instrument with -Xcomp
          if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
            throw_circularity_error = true;
          } else {
            // case 1: traditional: should never see load_in_progress.
            while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {

              // case 4: bootstrap classloader: prevent futile classloading,
              // wait on first requestor
              if (class_loader.is_null()) {
                SystemDictionary_lock->wait();
              } else {
              // case 2: traditional with broken classloader lock. wait on first
              // requestor.
                double_lock_wait(lockObject, THREAD);
              }
              // Check if classloading completed while we were waiting
714
              Klass* check = find_class(d_index, d_hash, name, loader_data);
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              if (check != NULL) {
                // Klass is already loaded, so just return it
                k = instanceKlassHandle(THREAD, check);
                class_has_been_loaded = true;
              }
              // check if other thread failed to load and cleaned up
721
              oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
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            }
          }
        }
      }
726
      // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
727
      // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try
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      // LOAD_INSTANCE in parallel
729

730
      if (!throw_circularity_error && !class_has_been_loaded) {
731
        PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
732
        load_instance_added = true;
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        // For class loaders that do not acquire the classloader object lock,
        // if they did not catch another thread holding LOAD_INSTANCE,
        // need a check analogous to the acquire ObjectLocker/find_class
        // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
        // one final check if the load has already completed
738
        // class loaders holding the ObjectLock shouldn't find the class here
739
        Klass* check = find_class(d_index, d_hash, name, loader_data);
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        if (check != NULL) {
741
        // Klass is already loaded, so return it after checking/adding protection domain
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          k = instanceKlassHandle(THREAD, check);
          class_has_been_loaded = true;
        }
      }
    }
747

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    // must throw error outside of owning lock
    if (throw_circularity_error) {
750
      assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
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      ResourceMark rm(THREAD);
752
      THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
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    }

    if (!class_has_been_loaded) {

      // Do actual loading
      k = load_instance_class(name, class_loader, THREAD);

760
      // For UnsyncloadClass only
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      // If they got a linkageError, check if a parallel class load succeeded.
      // If it did, then for bytecode resolution the specification requires
      // that we return the same result we did for the other thread, i.e. the
764
      // successfully loaded InstanceKlass
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      // Should not get here for classloaders that support parallelism
766
      // with the new cleaner mechanism, even with AllowParallelDefineClass
767
      // Bootstrap goes through here to allow for an extra guarantee check
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      if (UnsyncloadClass || (class_loader.is_null())) {
        if (k.is_null() && HAS_PENDING_EXCEPTION
770
          && PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass())) {
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          MutexLocker mu(SystemDictionary_lock, THREAD);
772
          Klass* check = find_class(d_index, d_hash, name, loader_data);
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          if (check != NULL) {
            // Klass is already loaded, so just use it
            k = instanceKlassHandle(THREAD, check);
            CLEAR_PENDING_EXCEPTION;
            guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?");
          }
        }
      }

      // If everything was OK (no exceptions, no null return value), and
      // class_loader is NOT the defining loader, do a little more bookkeeping.
      if (!HAS_PENDING_EXCEPTION && !k.is_null() &&
        k->class_loader() != class_loader()) {

        check_constraints(d_index, d_hash, k, class_loader, false, THREAD);

        // Need to check for a PENDING_EXCEPTION again; check_constraints
        // can throw and doesn't use the CHECK macro.
        if (!HAS_PENDING_EXCEPTION) {
          { // Grabbing the Compile_lock prevents systemDictionary updates
            // during compilations.
            MutexLocker mu(Compile_lock, THREAD);
            update_dictionary(d_index, d_hash, p_index, p_hash,
                            k, class_loader, THREAD);
          }
          if (JvmtiExport::should_post_class_load()) {
            Thread *thread = THREAD;
            assert(thread->is_Java_thread(), "thread->is_Java_thread()");
            JvmtiExport::post_class_load((JavaThread *) thread, k());
          }
        }
      }
805 806
    } // load_instance_class loop

807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832
    if (HAS_PENDING_EXCEPTION) {
      // An exception, such as OOM could have happened at various places inside
      // load_instance_class. We might have partially initialized a shared class
      // and need to clean it up.
      if (class_loader.is_null()) {
        // In some cases k may be null. Let's find the shared class again.
        instanceKlassHandle ik(THREAD, find_shared_class(name));
        if (ik.not_null()) {
          if (ik->class_loader_data() == NULL) {
            // We didn't go as far as Klass::restore_unshareable_info(),
            // so nothing to clean up.
          } else {
            MutexLocker mu(SystemDictionary_lock, THREAD);
            Klass* kk = find_class(name, ik->class_loader_data());
            if (kk != NULL) {
              // No clean up is needed if the shared class has been entered
              // into system dictionary, as load_shared_class() won't be called
              // again.
            } else {
              clean_up_shared_class(ik, class_loader, THREAD);
            }
          }
        }
      }
    }

833 834 835 836 837 838 839
    if (load_instance_added == true) {
      // clean up placeholder entries for LOAD_INSTANCE success or error
      // This brackets the SystemDictionary updates for both defining
      // and initiating loaders
      MutexLocker mu(SystemDictionary_lock, THREAD);
        placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
        SystemDictionary_lock->notify_all();
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    }
  }

843 844 845 846
  if (HAS_PENDING_EXCEPTION || k.is_null()) {
    return NULL;
  }

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#ifdef ASSERT
  {
849
    ClassLoaderData* loader_data = k->class_loader_data();
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    MutexLocker mu(SystemDictionary_lock, THREAD);
851
    Klass* kk = find_class(name, loader_data);
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    assert(kk == k(), "should be present in dictionary");
  }
#endif

  // return if the protection domain in NULL
  if (protection_domain() == NULL) return k();

  // Check the protection domain has the right access
  {
    MutexLocker mu(SystemDictionary_lock, THREAD);
    // Note that we have an entry, and entries can be deleted only during GC,
    // so we cannot allow GC to occur while we're holding this entry.
    // We're using a No_Safepoint_Verifier to catch any place where we
    // might potentially do a GC at all.
866 867
    // Dictionary::do_unloading() asserts that classes in SD are only
    // unloaded at a safepoint. Anonymous classes are not in SD.
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    No_Safepoint_Verifier nosafepoint;
    if (dictionary()->is_valid_protection_domain(d_index, d_hash, name,
870
                                                 loader_data,
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                                                 protection_domain)) {
      return k();
    }
  }

  // Verify protection domain. If it fails an exception is thrown
877
  validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
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  return k();
}


// This routine does not lock the system dictionary.
//
// Since readers don't hold a lock, we must make sure that system
// dictionary entries are only removed at a safepoint (when only one
// thread is running), and are added to in a safe way (all links must
// be updated in an MT-safe manner).
//
// Callers should be aware that an entry could be added just after
// _dictionary->bucket(index) is read here, so the caller will not see
// the new entry.

894
Klass* SystemDictionary::find(Symbol* class_name,
895 896 897
                              Handle class_loader,
                              Handle protection_domain,
                              TRAPS) {
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899 900 901 902 903
  // UseNewReflection
  // The result of this call should be consistent with the result
  // of the call to resolve_instance_class_or_null().
  // See evaluation 6790209 and 4474172 for more details.
  class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
904 905 906 907 908 909 910
  ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());

  if (loader_data == NULL) {
    // If the ClassLoaderData has not been setup,
    // then the class loader has no entries in the dictionary.
    return NULL;
  }
911

912
  unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
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  int d_index = dictionary()->hash_to_index(d_hash);

  {
    // Note that we have an entry, and entries can be deleted only during GC,
    // so we cannot allow GC to occur while we're holding this entry.
    // We're using a No_Safepoint_Verifier to catch any place where we
    // might potentially do a GC at all.
920 921
    // Dictionary::do_unloading() asserts that classes in SD are only
    // unloaded at a safepoint. Anonymous classes are not in SD.
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    No_Safepoint_Verifier nosafepoint;
923
    return dictionary()->find(d_index, d_hash, class_name, loader_data,
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                              protection_domain, THREAD);
  }
}


// Look for a loaded instance or array klass by name.  Do not do any loading.
// return NULL in case of error.
931
Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
932 933 934
                                                      Handle class_loader,
                                                      Handle protection_domain,
                                                      TRAPS) {
935
  Klass* k = NULL;
936
  assert(class_name != NULL, "class name must be non NULL");
937

938
  if (FieldType::is_array(class_name)) {
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    // The name refers to an array.  Parse the name.
940 941 942 943
    // dimension and object_key in FieldArrayInfo are assigned as a
    // side-effect of this call
    FieldArrayInfo fd;
    BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
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    if (t != T_OBJECT) {
      k = Universe::typeArrayKlassObj(t);
    } else {
947
      k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
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    }
    if (k != NULL) {
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      k = k->array_klass_or_null(fd.dimension());
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    }
  } else {
    k = find(class_name, class_loader, protection_domain, THREAD);
  }
  return k;
}

// Note: this method is much like resolve_from_stream, but
// updates no supplemental data structures.
// TODO consolidate the two methods with a helper routine?
961
Klass* SystemDictionary::parse_stream(Symbol* class_name,
962 963 964 965 966 967
                                      Handle class_loader,
                                      Handle protection_domain,
                                      ClassFileStream* st,
                                      KlassHandle host_klass,
                                      GrowableArray<Handle>* cp_patches,
                                      TRAPS) {
968
  TempNewSymbol parsed_name = NULL;
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970 971 972 973 974 975 976 977 978 979 980 981
  ClassLoaderData* loader_data;
  if (host_klass.not_null()) {
    // Create a new CLD for anonymous class, that uses the same class loader
    // as the host_klass
    assert(EnableInvokeDynamic, "");
    guarantee(host_klass->class_loader() == class_loader(), "should be the same");
    loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader(), CHECK_NULL);
    loader_data->record_dependency(host_klass(), CHECK_NULL);
  } else {
    loader_data = ClassLoaderData::class_loader_data(class_loader());
  }

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  // Parse the stream. Note that we do this even though this klass might
  // already be present in the SystemDictionary, otherwise we would not
  // throw potential ClassFormatErrors.
  //
  // Note: "name" is updated.

  instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
989
                                                             loader_data,
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                                                             protection_domain,
991 992
                                                             host_klass,
                                                             cp_patches,
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                                                             parsed_name,
994
                                                             true,
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                                                             THREAD);


998
  if (host_klass.not_null() && k.not_null()) {
999
    assert(EnableInvokeDynamic, "");
1000
    k->set_host_klass(host_klass());
1001
    // If it's anonymous, initialize it now, since nobody else will.
1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012

    {
      MutexLocker mu_r(Compile_lock, THREAD);

      // Add to class hierarchy, initialize vtables, and do possible
      // deoptimizations.
      add_to_hierarchy(k, CHECK_NULL); // No exception, but can block

      // But, do not add to system dictionary.
    }

1013
    // Rewrite and patch constant pool here.
1014
    k->link_class(CHECK_NULL);
1015 1016 1017
    if (cp_patches != NULL) {
      k->constants()->patch_resolved_references(cp_patches);
    }
1018
    k->eager_initialize(CHECK_NULL);
1019 1020 1021 1022 1023 1024 1025

    // notify jvmti
    if (JvmtiExport::should_post_class_load()) {
        assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
        JvmtiExport::post_class_load((JavaThread *) THREAD, k());
    }
  }
1026 1027
  assert(host_klass.not_null() || cp_patches == NULL,
         "cp_patches only found with host_klass");
1028

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  return k();
}

// Add a klass to the system from a stream (called by jni_DefineClass and
// JVM_DefineClass).
// Note: class_name can be NULL. In that case we do not know the name of
// the class until we have parsed the stream.

1037
Klass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1038 1039 1040 1041 1042
                                             Handle class_loader,
                                             Handle protection_domain,
                                             ClassFileStream* st,
                                             bool verify,
                                             TRAPS) {
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1044 1045 1046 1047 1048 1049 1050
  // Classloaders that support parallelism, e.g. bootstrap classloader,
  // or all classloaders with UnsyncloadClass do not acquire lock here
  bool DoObjectLock = true;
  if (is_parallelCapable(class_loader)) {
    DoObjectLock = false;
  }

1051
  ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL);
1052

1053
  // Make sure we are synchronized on the class loader before we proceed
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  Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
  check_loader_lock_contention(lockObject, THREAD);
1056
  ObjectLocker ol(lockObject, THREAD, DoObjectLock);
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1058
  TempNewSymbol parsed_name = NULL;
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  // Parse the stream. Note that we do this even though this klass might
  // already be present in the SystemDictionary, otherwise we would not
  // throw potential ClassFormatErrors.
  //
  // Note: "name" is updated.

  instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
1067
                                                             loader_data,
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                                                             protection_domain,
                                                             parsed_name,
1070
                                                             verify,
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                                                             THREAD);

  const char* pkg = "java/";
  if (!HAS_PENDING_EXCEPTION &&
      !class_loader.is_null() &&
1076
      parsed_name != NULL &&
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      !strncmp((const char*)parsed_name->bytes(), pkg, strlen(pkg))) {
    // It is illegal to define classes in the "java." package from
    // JVM_DefineClass or jni_DefineClass unless you're the bootclassloader
    ResourceMark rm(THREAD);
    char* name = parsed_name->as_C_string();
    char* index = strrchr(name, '/');
    *index = '\0'; // chop to just the package name
    while ((index = strchr(name, '/')) != NULL) {
      *index = '.'; // replace '/' with '.' in package name
    }
    const char* fmt = "Prohibited package name: %s";
    size_t len = strlen(fmt) + strlen(name);
    char* message = NEW_RESOURCE_ARRAY(char, len);
    jio_snprintf(message, len, fmt, name);
    Exceptions::_throw_msg(THREAD_AND_LOCATION,
      vmSymbols::java_lang_SecurityException(), message);
  }

  if (!HAS_PENDING_EXCEPTION) {
1096 1097
    assert(parsed_name != NULL, "Sanity");
    assert(class_name == NULL || class_name == parsed_name, "name mismatch");
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    // Verification prevents us from creating names with dots in them, this
    // asserts that that's the case.
    assert(is_internal_format(parsed_name),
           "external class name format used internally");

    // Add class just loaded
1104
    // If a class loader supports parallel classloading handle parallel define requests
1105
    // find_or_define_instance_class may return a different InstanceKlass
1106 1107 1108 1109 1110
    if (is_parallelCapable(class_loader)) {
      k = find_or_define_instance_class(class_name, class_loader, k, THREAD);
    } else {
      define_instance_class(k, THREAD);
    }
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  }

1113
  // Make sure we have an entry in the SystemDictionary on success
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  debug_only( {
    if (!HAS_PENDING_EXCEPTION) {
1116 1117
      assert(parsed_name != NULL, "parsed_name is still null?");
      Symbol*  h_name    = k->name();
1118
      ClassLoaderData *defining_loader_data = k->class_loader_data();
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      MutexLocker mu(SystemDictionary_lock, THREAD);

1122
      Klass* check = find_class(parsed_name, loader_data);
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      assert(check == k(), "should be present in the dictionary");

1125
      Klass* check2 = find_class(h_name, defining_loader_data);
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      assert(check == check2, "name inconsistancy in SystemDictionary");
    }
  } );

  return k();
}


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void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
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                                             int number_of_entries) {
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  assert(length == _nof_buckets * sizeof(HashtableBucket<mtClass>),
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         "bad shared dictionary size.");
  _shared_dictionary = new Dictionary(_nof_buckets, t, number_of_entries);
}


// If there is a shared dictionary, then find the entry for the
// given shared system class, if any.

1145
Klass* SystemDictionary::find_shared_class(Symbol* class_name) {
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  if (shared_dictionary() != NULL) {
1147
    unsigned int d_hash = shared_dictionary()->compute_hash(class_name, NULL);
1148
    int d_index = shared_dictionary()->hash_to_index(d_hash);
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    return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
  } else {
    return NULL;
  }
}


// Load a class from the shared spaces (found through the shared system
// dictionary).  Force the superclass and all interfaces to be loaded.
// Update the class definition to include sibling classes and no
// subclasses (yet).  [Classes in the shared space are not part of the
// object hierarchy until loaded.]

instanceKlassHandle SystemDictionary::load_shared_class(
1164
                 Symbol* class_name, Handle class_loader, TRAPS) {
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  instanceKlassHandle ik (THREAD, find_shared_class(class_name));
  return load_shared_class(ik, class_loader, THREAD);
}

instanceKlassHandle SystemDictionary::load_shared_class(
                 instanceKlassHandle ik, Handle class_loader, TRAPS) {
  assert(class_loader.is_null(), "non-null classloader for shared class?");
  if (ik.not_null()) {
    instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1174
    Symbol*  class_name = ik->name();
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    // Found the class, now load the superclass and interfaces.  If they
    // are shared, add them to the main system dictionary and reset
    // their hierarchy references (supers, subs, and interfaces).

    if (ik->super() != NULL) {
1181
      Symbol*  cn = ik->super()->name();
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      resolve_super_or_fail(class_name, cn,
                            class_loader, Handle(), true, CHECK_(nh));
    }

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    Array<Klass*>* interfaces = ik->local_interfaces();
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    int num_interfaces = interfaces->length();
    for (int index = 0; index < num_interfaces; index++) {
1189
      Klass* k = interfaces->at(index);
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      // Note: can not use InstanceKlass::cast here because
      // interfaces' InstanceKlass's C++ vtbls haven't been
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      // reinitialized yet (they will be once the interface classes
      // are loaded)
1195
      Symbol*  name  = k->name();
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      resolve_super_or_fail(class_name, name, class_loader, Handle(), false, CHECK_(nh));
    }

    // Adjust methods to recover missing data.  They need addresses for
    // interpreter entry points and their default native method address
    // must be reset.

    // Updating methods must be done under a lock so multiple
    // threads don't update these in parallel
    // Shared classes are all currently loaded by the bootstrap
    // classloader, so this will never cause a deadlock on
    // a custom class loader lock.

    {
      Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
      check_loader_lock_contention(lockObject, THREAD);
      ObjectLocker ol(lockObject, THREAD, true);
1213
      ik->restore_unshareable_info(CHECK_(nh));
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    }

    if (TraceClassLoading) {
      ResourceMark rm;
      tty->print("[Loaded %s", ik->external_name());
      tty->print(" from shared objects file");
      tty->print_cr("]");
    }
    // notify a class loaded from shared object
1223
    ClassLoadingService::notify_class_loaded(InstanceKlass::cast(ik()),
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                                             true /* shared class */);
  }
  return ik;
}

1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241
void SystemDictionary::clean_up_shared_class(instanceKlassHandle ik, Handle class_loader, TRAPS) {
  // Updating methods must be done under a lock so multiple
  // threads don't update these in parallel
  // Shared classes are all currently loaded by the bootstrap
  // classloader, so this will never cause a deadlock on
  // a custom class loader lock.
  {
    Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
    check_loader_lock_contention(lockObject, THREAD);
    ObjectLocker ol(lockObject, THREAD, true);
    ik->remove_unshareable_info();
  }
}
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1243
instanceKlassHandle SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
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  instanceKlassHandle nh = instanceKlassHandle(); // null Handle
  if (class_loader.is_null()) {
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    // Search the shared system dictionary for classes preloaded into the
    // shared spaces.
    instanceKlassHandle k;
1250 1251 1252 1253
    {
      PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
      k = load_shared_class(class_name, class_loader, THREAD);
    }
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    if (k.is_null()) {
      // Use VM class loader
1257
      PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
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      k = ClassLoader::load_classfile(class_name, CHECK_(nh));
    }

1261
    // find_or_define_instance_class may return a different InstanceKlass
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    if (!k.is_null()) {
      k = find_or_define_instance_class(class_name, class_loader, k, CHECK_(nh));
    }
    return k;
  } else {
    // Use user specified class loader to load class. Call loadClass operation on class_loader.
    ResourceMark rm(THREAD);

1270 1271 1272 1273 1274 1275 1276 1277 1278 1279
    assert(THREAD->is_Java_thread(), "must be a JavaThread");
    JavaThread* jt = (JavaThread*) THREAD;

    PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
                               ClassLoader::perf_app_classload_selftime(),
                               ClassLoader::perf_app_classload_count(),
                               jt->get_thread_stat()->perf_recursion_counts_addr(),
                               jt->get_thread_stat()->perf_timers_addr(),
                               PerfClassTraceTime::CLASS_LOAD);

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    Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nh));
    // Translate to external class name format, i.e., convert '/' chars to '.'
    Handle string = java_lang_String::externalize_classname(s, CHECK_(nh));

    JavaValue result(T_OBJECT);

1286
    KlassHandle spec_klass (THREAD, SystemDictionary::ClassLoader_klass());
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1288 1289 1290 1291 1292 1293 1294 1295 1296 1297
    // Call public unsynchronized loadClass(String) directly for all class loaders
    // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will
    // acquire a class-name based lock rather than the class loader object lock.
    // JDK < 7 already acquire the class loader lock in loadClass(String, boolean),
    // so the call to loadClassInternal() was not required.
    //
    // UnsyncloadClass flag means both call loadClass(String) and do
    // not acquire the class loader lock even for class loaders that are
    // not parallelCapable. This was a risky transitional
    // flag for diagnostic purposes only. It is risky to call
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    // custom class loaders without synchronization.
    // WARNING If a custom class loader does NOT synchronizer findClass, or callers of
1300
    // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field.
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    // Do NOT assume this will be supported in future releases.
1302 1303 1304 1305
    //
    // Added MustCallLoadClassInternal in case we discover in the field
    // a customer that counts on this call
    if (MustCallLoadClassInternal && has_loadClassInternal()) {
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      JavaCalls::call_special(&result,
                              class_loader,
                              spec_klass,
1309 1310
                              vmSymbols::loadClassInternal_name(),
                              vmSymbols::string_class_signature(),
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                              string,
                              CHECK_(nh));
    } else {
      JavaCalls::call_virtual(&result,
                              class_loader,
                              spec_klass,
1317 1318
                              vmSymbols::loadClass_name(),
                              vmSymbols::string_class_signature(),
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                              string,
                              CHECK_(nh));
    }

    assert(result.get_type() == T_OBJECT, "just checking");
    oop obj = (oop) result.get_jobject();

    // Primitive classes return null since forName() can not be
    // used to obtain any of the Class objects representing primitives or void
    if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
      instanceKlassHandle k =
1330
                instanceKlassHandle(THREAD, java_lang_Class::as_Klass(obj));
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      // For user defined Java class loaders, check that the name returned is
      // the same as that requested.  This check is done for the bootstrap
      // loader when parsing the class file.
1334
      if (class_name == k->name()) {
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        return k;
      }
    }
    // Class is not found or has the wrong name, return NULL
    return nh;
  }
}

void SystemDictionary::define_instance_class(instanceKlassHandle k, TRAPS) {

1345 1346 1347 1348
  ClassLoaderData* loader_data = k->class_loader_data();
  Handle class_loader_h(THREAD, loader_data->class_loader());

  for (uintx it = 0; it < GCExpandToAllocateDelayMillis; it++){}
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1350 1351 1352 1353 1354 1355
 // for bootstrap and other parallel classloaders don't acquire lock,
 // use placeholder token
 // If a parallelCapable class loader calls define_instance_class instead of
 // find_or_define_instance_class to get here, we have a timing
 // hole with systemDictionary updates and check_constraints
 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
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    assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
         compute_loader_lock_object(class_loader_h, THREAD)),
         "define called without lock");
  }

  // Check class-loading constraints. Throw exception if violation is detected.
  // Grabs and releases SystemDictionary_lock
  // The check_constraints/find_class call and update_dictionary sequence
  // must be "atomic" for a specific class/classloader pair so we never
  // define two different instanceKlasses for that class/classloader pair.
  // Existing classloaders will call define_instance_class with the
  // classloader lock held
  // Parallel classloaders will call find_or_define_instance_class
  // which will require a token to perform the define class
1370
  Symbol*  name_h = k->name();
1371
  unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
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  int d_index = dictionary()->hash_to_index(d_hash);
  check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK);

1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387
  // Register class just loaded with class loader (placed in Vector)
  // Note we do this before updating the dictionary, as this can
  // fail with an OutOfMemoryError (if it does, we will *not* put this
  // class in the dictionary and will not update the class hierarchy).
  // JVMTI FollowReferences needs to find the classes this way.
  if (k->class_loader() != NULL) {
    methodHandle m(THREAD, Universe::loader_addClass_method());
    JavaValue result(T_VOID);
    JavaCallArguments args(class_loader_h);
    args.push_oop(Handle(THREAD, k->java_mirror()));
    JavaCalls::call(&result, m, &args, CHECK);
  }

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  // Add the new class. We need recompile lock during update of CHA.
  {
1390
    unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
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    int p_index = placeholders()->hash_to_index(p_hash);

    MutexLocker mu_r(Compile_lock, THREAD);

    // Add to class hierarchy, initialize vtables, and do possible
    // deoptimizations.
    add_to_hierarchy(k, CHECK); // No exception, but can block

    // Add to systemDictionary - so other classes can see it.
    // Grabs and releases SystemDictionary_lock
    update_dictionary(d_index, d_hash, p_index, p_hash,
                      k, class_loader_h, THREAD);
  }
  k->eager_initialize(THREAD);

  // notify jvmti
  if (JvmtiExport::should_post_class_load()) {
      assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
      JvmtiExport::post_class_load((JavaThread *) THREAD, k());

  }
}

// Support parallel classloading
1415 1416 1417
// All parallel class loaders, including bootstrap classloader
// lock a placeholder entry for this class/class_loader pair
// to allow parallel defines of different classes for this class loader
1418 1419
// With AllowParallelDefine flag==true, in case they do not synchronize around
// FindLoadedClass/DefineClass, calls, we check for parallel
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// loading for them, wait if a defineClass is in progress
// and return the initial requestor's results
1422
// This flag does not apply to the bootstrap classloader.
1423 1424
// With AllowParallelDefine flag==false, call through to define_instance_class
// which will throw LinkageError: duplicate class definition.
1425
// False is the requested default.
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// For better performance, the class loaders should synchronize
1427
// findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
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// potentially waste time reading and parsing the bytestream.
// Note: VM callers should ensure consistency of k/class_name,class_loader
1430
instanceKlassHandle SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader, instanceKlassHandle k, TRAPS) {
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1431 1432

  instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1433
  Symbol*  name_h = k->name(); // passed in class_name may be null
1434
  ClassLoaderData* loader_data = class_loader_data(class_loader);
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1436
  unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
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  int d_index = dictionary()->hash_to_index(d_hash);

// Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1440
  unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
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  int p_index = placeholders()->hash_to_index(p_hash);
  PlaceholderEntry* probe;

  {
    MutexLocker mu(SystemDictionary_lock, THREAD);
    // First check if class already defined
1447
    if (UnsyncloadClass || (is_parallelDefine(class_loader))) {
1448
      Klass* check = find_class(d_index, d_hash, name_h, loader_data);
1449 1450 1451
      if (check != NULL) {
        return(instanceKlassHandle(THREAD, check));
      }
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    }

    // Acquire define token for this class/classloader
1455
    probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1456 1457 1458 1459 1460 1461 1462 1463 1464 1465
    // Wait if another thread defining in parallel
    // All threads wait - even those that will throw duplicate class: otherwise
    // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
    // if other thread has not finished updating dictionary
    while (probe->definer() != NULL) {
      SystemDictionary_lock->wait();
    }
    // Only special cases allow parallel defines and can use other thread's results
    // Other cases fall through, and may run into duplicate defines
    // caught by finding an entry in the SystemDictionary
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    if ((UnsyncloadClass || is_parallelDefine(class_loader)) && (probe->instance_klass() != NULL)) {
1467
        placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1468
        SystemDictionary_lock->notify_all();
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#ifdef ASSERT
1470
        Klass* check = find_class(d_index, d_hash, name_h, loader_data);
1471
        assert(check != NULL, "definer missed recording success");
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#endif
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        return(instanceKlassHandle(THREAD, probe->instance_klass()));
1474 1475 1476
    } else {
      // This thread will define the class (even if earlier thread tried and had an error)
      probe->set_definer(THREAD);
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    }
  }

  define_instance_class(k, THREAD);

  Handle linkage_exception = Handle(); // null handle

  // definer must notify any waiting threads
  {
    MutexLocker mu(SystemDictionary_lock, THREAD);
1487
    PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
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    assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
    if (probe != NULL) {
      if (HAS_PENDING_EXCEPTION) {
        linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
        CLEAR_PENDING_EXCEPTION;
      } else {
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        probe->set_instance_klass(k());
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      }
      probe->set_definer(NULL);
1497
      placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
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      SystemDictionary_lock->notify_all();
    }
  }

  // Can't throw exception while holding lock due to rank ordering
  if (linkage_exception() != NULL) {
    THROW_OOP_(linkage_exception(), nh); // throws exception and returns
  }

  return k;
}
Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
  // If class_loader is NULL we synchronize on _system_loader_lock_obj
  if (class_loader.is_null()) {
    return Handle(THREAD, _system_loader_lock_obj);
  } else {
    return class_loader;
  }
}

// This method is added to check how often we have to wait to grab loader
// lock. The results are being recorded in the performance counters defined in
// ClassLoader::_sync_systemLoaderLockContentionRate and
// ClassLoader::_sync_nonSystemLoaderLockConteionRate.
void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
  if (!UsePerfData) {
    return;
  }

  assert(!loader_lock.is_null(), "NULL lock object");

  if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
      == ObjectSynchronizer::owner_other) {
    // contention will likely happen, so increment the corresponding
    // contention counter.
    if (loader_lock() == _system_loader_lock_obj) {
      ClassLoader::sync_systemLoaderLockContentionRate()->inc();
    } else {
      ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
    }
  }
}

// ----------------------------------------------------------------------------
// Lookup

1544
Klass* SystemDictionary::find_class(int index, unsigned int hash,
1545
                                      Symbol* class_name,
1546
                                      ClassLoaderData* loader_data) {
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  assert_locked_or_safepoint(SystemDictionary_lock);
1548
  assert (index == dictionary()->index_for(class_name, loader_data),
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          "incorrect index?");

1551
  Klass* k = dictionary()->find_class(index, hash, class_name, loader_data);
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  return k;
}


// Basic find on classes in the midst of being loaded
1557
Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1558
                                           ClassLoaderData* loader_data) {
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  assert_locked_or_safepoint(SystemDictionary_lock);
1560
  unsigned int p_hash = placeholders()->compute_hash(class_name, loader_data);
1561
  int p_index = placeholders()->hash_to_index(p_hash);
1562
  return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
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}


// Used for assertions and verification only
1567
Klass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
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  #ifndef ASSERT
  guarantee(VerifyBeforeGC   ||
            VerifyDuringGC   ||
            VerifyBeforeExit ||
            VerifyAfterGC, "too expensive");
  #endif
  assert_locked_or_safepoint(SystemDictionary_lock);

  // First look in the loaded class array
1577
  unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
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  int d_index = dictionary()->hash_to_index(d_hash);
1579
  return find_class(d_index, d_hash, class_name, loader_data);
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}


// Get the next class in the diictionary.
1584
Klass* SystemDictionary::try_get_next_class() {
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  return dictionary()->try_get_next_class();
}


// ----------------------------------------------------------------------------
// Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
// is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
// before a new class is used.

void SystemDictionary::add_to_hierarchy(instanceKlassHandle k, TRAPS) {
  assert(k.not_null(), "just checking");
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  assert_locked_or_safepoint(Compile_lock);

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  // Link into hierachy. Make sure the vtables are initialized before linking into
  k->append_to_sibling_list();                    // add to superklass/sibling list
  k->process_interfaces(THREAD);                  // handle all "implements" declarations
1601
  k->set_init_state(InstanceKlass::loaded);
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  // Now flush all code that depended on old class hierarchy.
  // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
  // Also, first reinitialize vtable because it may have gotten out of synch
  // while the new class wasn't connected to the class hierarchy.
  Universe::flush_dependents_on(k);
}


// ----------------------------------------------------------------------------
// GC support

// Following roots during mark-sweep is separated in two phases.
//
// The first phase follows preloaded classes and all other system
// classes, since these will never get unloaded anyway.
//
// The second phase removes (unloads) unreachable classes from the
// system dictionary and follows the remaining classes' contents.

void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
  blk->do_oop(&_java_system_loader);
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  blk->do_oop(&_system_loader_lock_obj);
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1625
  dictionary()->always_strong_oops_do(blk);
1626 1627 1628

  // Visit extra methods
  invoke_method_table()->oops_do(blk);
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}

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void SystemDictionary::always_strong_classes_do(KlassClosure* closure) {
  // Follow all system classes and temporary placeholders in dictionary
  dictionary()->always_strong_classes_do(closure);
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1635 1636
  // Placeholders. These represent classes we're actively loading.
  placeholders()->classes_do(closure);
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}

1639 1640 1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653
// Calculate a "good" systemdictionary size based
// on predicted or current loaded classes count
int SystemDictionary::calculate_systemdictionary_size(int classcount) {
  int newsize = _old_default_sdsize;
  if ((classcount > 0)  && !DumpSharedSpaces) {
    int desiredsize = classcount/_average_depth_goal;
    for (newsize = _primelist[_sdgeneration]; _sdgeneration < _prime_array_size -1;
         newsize = _primelist[++_sdgeneration]) {
      if (desiredsize <=  newsize) {
        break;
      }
    }
  }
  return newsize;
}
1654 1655
// Assumes classes in the SystemDictionary are only unloaded at a safepoint
// Note: anonymous classes are not in the SD.
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bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive) {
1657 1658 1659 1660 1661 1662 1663 1664 1665
  // First, mark for unload all ClassLoaderData referencing a dead class loader.
  bool has_dead_loaders = ClassLoaderDataGraph::do_unloading(is_alive);
  bool unloading_occurred = false;
  if (has_dead_loaders) {
    unloading_occurred = dictionary()->do_unloading();
    constraints()->purge_loader_constraints();
    resolution_errors()->purge_resolution_errors();
}
  return unloading_occurred;
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}

void SystemDictionary::oops_do(OopClosure* f) {
  f->do_oop(&_java_system_loader);
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  f->do_oop(&_system_loader_lock_obj);
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  // Adjust dictionary
  dictionary()->oops_do(f);

1675
  // Visit extra methods
1676
  invoke_method_table()->oops_do(f);
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}

1679 1680 1681 1682 1683
// Extended Class redefinition support.
// If one of these classes is replaced, we need to replace it in these places.
// KlassClosure::do_klass should take the address of a class but we can
// change that later.
void SystemDictionary::preloaded_classes_do(KlassClosure* f) {
1684
  for (int k = (int)FIRST_WKID; k < (int)WKID_LIMIT; k++) {
1685
    f->do_klass(_well_known_klasses[k]);
1686 1687
  }

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  {
    for (int i = 0; i < T_VOID+1; i++) {
      if (_box_klasses[i] != NULL) {
        assert(i >= T_BOOLEAN, "checking");
1692
        f->do_klass(_box_klasses[i]);
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      }
    }
  }

1697
  FilteredFieldsMap::classes_do(f);
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}

1700 1701
void SystemDictionary::lazily_loaded_classes_do(KlassClosure* f) {
  f->do_klass(_abstract_ownable_synchronizer_klass);
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}

// Just the classes from defining class loaders
// Don't iterate over placeholders
1706
void SystemDictionary::classes_do(void f(Klass*)) {
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  dictionary()->classes_do(f);
}

// Added for initialize_itable_for_klass
//   Just the classes from defining class loaders
// Don't iterate over placeholders
1713
void SystemDictionary::classes_do(void f(Klass*, TRAPS), TRAPS) {
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  dictionary()->classes_do(f, CHECK);
}

//   All classes, and their class loaders
// Don't iterate over placeholders
1719
void SystemDictionary::classes_do(void f(Klass*, ClassLoaderData*)) {
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  dictionary()->classes_do(f);
}

//   All classes, and their class loaders
//   (added for helpers that use HandleMarks and ResourceMarks)
// Don't iterate over placeholders
1726
void SystemDictionary::classes_do(void f(Klass*, ClassLoaderData*, TRAPS), TRAPS) {
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  dictionary()->classes_do(f, CHECK);
}

1730
void SystemDictionary::placeholders_do(void f(Symbol*)) {
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  placeholders()->entries_do(f);
}

1734
void SystemDictionary::methods_do(void f(Method*)) {
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  dictionary()->methods_do(f);
1736
  invoke_method_table()->methods_do(f);
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}

// ----------------------------------------------------------------------------
// Lazily load klasses

void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
  assert(JDK_Version::is_gte_jdk16x_version(), "Must be JDK 1.6 or later");

  // if multiple threads calling this function, only one thread will load
  // the class.  The other threads will find the loaded version once the
  // class is loaded.
1748
  Klass* aos = _abstract_ownable_synchronizer_klass;
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  if (aos == NULL) {
1750
    Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
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    // Force a fence to prevent any read before the write completes
    OrderAccess::fence();
    _abstract_ownable_synchronizer_klass = k;
  }
}

// ----------------------------------------------------------------------------
// Initialization

void SystemDictionary::initialize(TRAPS) {
  // Allocate arrays
  assert(dictionary() == NULL,
         "SystemDictionary should only be initialized once");
1764 1765
  _sdgeneration        = 0;
  _dictionary          = new Dictionary(calculate_systemdictionary_size(PredictedLoadedClassCount));
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  _placeholders        = new PlaceholderTable(_nof_buckets);
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  _number_of_modifications = 0;
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  _loader_constraints  = new LoaderConstraintTable(_loader_constraint_size);
  _resolution_errors   = new ResolutionErrorTable(_resolution_error_size);
  _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
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  // Allocate private object used as system class loader lock
1773
  _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
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  // Initialize basic classes
  initialize_preloaded_classes(CHECK);
}

1778 1779 1780 1781 1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 1792
// Compact table of directions on the initialization of klasses:
static const short wk_init_info[] = {
  #define WK_KLASS_INIT_INFO(name, symbol, option) \
    ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
          << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
      | (int)SystemDictionary::option ),
  WK_KLASSES_DO(WK_KLASS_INIT_INFO)
  #undef WK_KLASS_INIT_INFO
  0
};

bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
  assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
  int  info = wk_init_info[id - FIRST_WKID];
  int  sid  = (info >> CEIL_LG_OPTION_LIMIT);
1793
  Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
1794
  Klass**    klassp = &_well_known_klasses[id];
1795
  bool must_load = (init_opt < SystemDictionary::Opt);
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  if ((*klassp) == NULL) {
1797 1798 1799 1800 1801 1802
    if (must_load) {
      (*klassp) = resolve_or_fail(symbol, true, CHECK_0); // load required class
    } else {
      (*klassp) = resolve_or_null(symbol,       CHECK_0); // load optional klass
    }
  }
1803
  return ((*klassp) != NULL);
1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814 1815
}

void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
  assert((int)start_id <= (int)limit_id, "IDs are out of order!");
  for (int id = (int)start_id; id < (int)limit_id; id++) {
    assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
    int info = wk_init_info[id - FIRST_WKID];
    int sid  = (info >> CEIL_LG_OPTION_LIMIT);
    int opt  = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));

    initialize_wk_klass((WKID)id, opt, CHECK);
  }
1816 1817 1818

  // move the starting value forward to the limit:
  start_id = limit_id;
1819 1820
}

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void SystemDictionary::initialize_preloaded_classes(TRAPS) {
1822
  assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
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  // Preload commonly used klasses
1824
  WKID scan = FIRST_WKID;
1825 1826 1827 1828 1829 1830
  // first do Object, then String, Class
  if (UseSharedSpaces) {
    initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
    // Initialize the constant pool for the Object_class
    InstanceKlass* ik = InstanceKlass::cast(Object_klass());
    ik->constants()->restore_unshareable_info(CHECK);
1831
    initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1832 1833 1834
  } else {
    initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
  }
1835

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  // Calculate offsets for String and Class classes since they are loaded and
  // can be used after this point.
  java_lang_String::compute_offsets();
1839
  java_lang_Class::compute_offsets();
1840

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  // Fixup mirrors for classes loaded before java.lang.Class.
  // These calls iterate over the objects currently in the perm gen
  // so calling them at this point is matters (not before when there
  // are fewer objects and not later after there are more objects
  // in the perm gen.
  Universe::initialize_basic_type_mirrors(CHECK);
  Universe::fixup_mirrors(CHECK);

1849
  // do a bunch more:
1850
  initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
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  // Preload ref klasses and set reference types
1853
  InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
1854
  InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
1855

1856
  initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
1857 1858 1859 1860
  InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
  InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
  InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
  InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
1861

1862 1863
  // JSR 292 classes
  WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
1864
  WKID jsr292_group_end   = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
1865
  initialize_wk_klasses_until(jsr292_group_start, scan, CHECK);
1866
  if (EnableInvokeDynamic) {
1867 1868 1869 1870
    initialize_wk_klasses_through(jsr292_group_end, scan, CHECK);
  } else {
    // Skip the JSR 292 classes, if not enabled.
    scan = WKID(jsr292_group_end + 1);
1871
  }
1872

1873 1874
  initialize_wk_klasses_until(WKID_LIMIT, scan, CHECK);

1875 1876 1877 1878 1879 1880 1881 1882
  _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
  _box_klasses[T_CHAR]    = WK_KLASS(Character_klass);
  _box_klasses[T_FLOAT]   = WK_KLASS(Float_klass);
  _box_klasses[T_DOUBLE]  = WK_KLASS(Double_klass);
  _box_klasses[T_BYTE]    = WK_KLASS(Byte_klass);
  _box_klasses[T_SHORT]   = WK_KLASS(Short_klass);
  _box_klasses[T_INT]     = WK_KLASS(Integer_klass);
  _box_klasses[T_LONG]    = WK_KLASS(Long_klass);
1883 1884 1885
  //_box_klasses[T_OBJECT]  = WK_KLASS(object_klass);
  //_box_klasses[T_ARRAY]   = WK_KLASS(object_klass);

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  { // Compute whether we should use loadClass or loadClassInternal when loading classes.
1887
    Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature());
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    _has_loadClassInternal = (method != NULL);
  }
  { // Compute whether we should use checkPackageAccess or NOT
1891
    Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
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    _has_checkPackageAccess = (method != NULL);
  }
}

// Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
// If so, returns the basic type it holds.  If not, returns T_OBJECT.
1898
BasicType SystemDictionary::box_klass_type(Klass* k) {
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  assert(k != NULL, "");
  for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
    if (_box_klasses[i] == k)
      return (BasicType)i;
  }
  return T_OBJECT;
}

// Constraints on class loaders. The details of the algorithm can be
// found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
// Virtual Machine" by Sheng Liang and Gilad Bracha.  The basic idea is
// that the system dictionary needs to maintain a set of contraints that
// must be satisfied by all classes in the dictionary.
// if defining is true, then LinkageError if already in systemDictionary
1913
// if initiating loader, then ok if InstanceKlass matches existing entry
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void SystemDictionary::check_constraints(int d_index, unsigned int d_hash,
                                         instanceKlassHandle k,
                                         Handle class_loader, bool defining,
                                         TRAPS) {
  const char *linkage_error = NULL;
  {
1921
    Symbol*  name  = k->name();
1922 1923
    ClassLoaderData *loader_data = class_loader_data(class_loader);

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    MutexLocker mu(SystemDictionary_lock, THREAD);

1926 1927 1928
    Klass* check = find_class(d_index, d_hash, name, loader_data);
    if (check != (Klass*)NULL) {
      // if different InstanceKlass - duplicate class definition,
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      // else - ok, class loaded by a different thread in parallel,
      // we should only have found it if it was done loading and ok to use
      // system dictionary only holds instance classes, placeholders
      // also holds array classes

1934
      assert(check->oop_is_instance(), "noninstance in systemdictionary");
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      if ((defining == true) || (k() != check)) {
        linkage_error = "loader (instance of  %s): attempted  duplicate class "
          "definition for name: \"%s\"";
      } else {
        return;
      }
    }

#ifdef ASSERT
1944
    Symbol* ph_check = find_placeholder(name, loader_data);
1945
    assert(ph_check == NULL || ph_check == name, "invalid symbol");
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#endif

    if (linkage_error == NULL) {
      if (constraints()->check_or_update(k, class_loader, name) == false) {
        linkage_error = "loader constraint violation: loader (instance of %s)"
          " previously initiated loading for a different type with name \"%s\"";
      }
    }
  }

  // Throw error now if needed (cannot throw while holding
  // SystemDictionary_lock because of rank ordering)

  if (linkage_error) {
    ResourceMark rm(THREAD);
    const char* class_loader_name = loader_name(class_loader());
    char* type_name = k->name()->as_C_string();
    size_t buflen = strlen(linkage_error) + strlen(class_loader_name) +
      strlen(type_name);
    char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
    jio_snprintf(buf, buflen, linkage_error, class_loader_name, type_name);
    THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
  }
}


// Update system dictionary - done after check_constraint and add_to_hierachy
// have been called.
void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash,
                                         int p_index, unsigned int p_hash,
                                         instanceKlassHandle k,
                                         Handle class_loader,
                                         TRAPS) {
  // Compile_lock prevents systemDictionary updates during compilations
  assert_locked_or_safepoint(Compile_lock);
1981
  Symbol*  name  = k->name();
1982
  ClassLoaderData *loader_data = class_loader_data(class_loader);
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  {
  MutexLocker mu1(SystemDictionary_lock, THREAD);

  // See whether biased locking is enabled and if so set it for this
  // klass.
  // Note that this must be done past the last potential blocking
  // point / safepoint. We enable biased locking lazily using a
  // VM_Operation to iterate the SystemDictionary and installing the
1992
  // biasable mark word into each InstanceKlass's prototype header.
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  // To avoid race conditions where we accidentally miss enabling the
  // optimization for one class in the process of being added to the
  // dictionary, we must not safepoint after the test of
  // BiasedLocking::enabled().
  if (UseBiasedLocking && BiasedLocking::enabled()) {
    // Set biased locking bit for all loaded classes; it will be
    // cleared if revocation occurs too often for this type
    // NOTE that we must only do this when the class is initally
    // defined, not each time it is referenced from a new class loader
    if (k->class_loader() == class_loader()) {
      k->set_prototype_header(markOopDesc::biased_locking_prototype());
    }
  }

2007 2008 2009 2010 2011 2012
  // Assign a classid if one has not already been assigned.  The
  // counter does not need to be atomically incremented since this
  // is only done while holding the SystemDictionary_lock.
  // All loaded classes get a unique ID.
  TRACE_INIT_ID(k);

2013
  // Make a new system dictionary entry.
2014
  Klass* sd_check = find_class(d_index, d_hash, name, loader_data);
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  if (sd_check == NULL) {
2016
    dictionary()->add_klass(name, loader_data, k);
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    notice_modification();
  }
#ifdef ASSERT
2020
  sd_check = find_class(d_index, d_hash, name, loader_data);
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  assert (sd_check != NULL, "should have entry in system dictionary");
2022 2023
  // Note: there may be a placeholder entry: for circularity testing
  // or for parallel defines
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2024 2025 2026 2027 2028 2029
#endif
    SystemDictionary_lock->notify_all();
  }
}


2030 2031 2032
// Try to find a class name using the loader constraints.  The
// loader constraints might know about a class that isn't fully loaded
// yet and these will be ignored.
2033
Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2034
                    Symbol* class_name, Handle class_loader, TRAPS) {
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2035 2036 2037 2038

  // First see if it has been loaded directly.
  // Force the protection domain to be null.  (This removes protection checks.)
  Handle no_protection_domain;
2039
  Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2040
                                              no_protection_domain, CHECK_NULL);
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2041 2042 2043 2044 2045 2046
  if (klass != NULL)
    return klass;

  // Now look to see if it has been loaded elsewhere, and is subject to
  // a loader constraint that would require this loader to return the
  // klass that is already loaded.
2047
  if (FieldType::is_array(class_name)) {
2048 2049
    // For array classes, their Klass*s are not kept in the
    // constraint table. The element Klass*s are.
2050 2051
    FieldArrayInfo fd;
    BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
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2052 2053 2054 2055
    if (t != T_OBJECT) {
      klass = Universe::typeArrayKlassObj(t);
    } else {
      MutexLocker mu(SystemDictionary_lock, THREAD);
2056
      klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
D
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2057
    }
2058
    // If element class already loaded, allocate array klass
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2059
    if (klass != NULL) {
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2060
      klass = klass->array_klass_or_null(fd.dimension());
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2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071
    }
  } else {
    MutexLocker mu(SystemDictionary_lock, THREAD);
    // Non-array classes are easy: simply check the constraint table.
    klass = constraints()->find_constrained_klass(class_name, class_loader);
  }

  return klass;
}


2072
bool SystemDictionary::add_loader_constraint(Symbol* class_name,
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2073 2074 2075
                                             Handle class_loader1,
                                             Handle class_loader2,
                                             Thread* THREAD) {
2076 2077 2078
  ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
  ClassLoaderData* loader_data2 = class_loader_data(class_loader2);

2079 2080
  Symbol* constraint_name = NULL;
  if (!FieldType::is_array(class_name)) {
2081 2082
    constraint_name = class_name;
  } else {
2083
    // For array classes, their Klass*s are not kept in the
2084
    // constraint table. The element classes are.
2085 2086
    FieldArrayInfo fd;
    BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2087 2088 2089 2090
    // primitive types always pass
    if (t != T_OBJECT) {
      return true;
    } else {
2091
      constraint_name = fd.object_key();
2092 2093
    }
  }
2094
  unsigned int d_hash1 = dictionary()->compute_hash(constraint_name, loader_data1);
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2095 2096
  int d_index1 = dictionary()->hash_to_index(d_hash1);

2097
  unsigned int d_hash2 = dictionary()->compute_hash(constraint_name, loader_data2);
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2098 2099
  int d_index2 = dictionary()->hash_to_index(d_hash2);
  {
2100
  MutexLocker mu_s(SystemDictionary_lock, THREAD);
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2101

2102 2103
  // Better never do a GC while we're holding these oops
  No_Safepoint_Verifier nosafepoint;
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2104

2105 2106
  Klass* klass1 = find_class(d_index1, d_hash1, constraint_name, loader_data1);
  Klass* klass2 = find_class(d_index2, d_hash2, constraint_name, loader_data2);
2107 2108
  return constraints()->add_entry(constraint_name, klass1, class_loader1,
                                  klass2, class_loader2);
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2109 2110 2111 2112 2113
  }
}

// Add entry to resolution error table to record the error when the first
// attempt to resolve a reference to a class has failed.
2114
void SystemDictionary::add_resolution_error(constantPoolHandle pool, int which, Symbol* error) {
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2115 2116 2117 2118 2119 2120 2121 2122
  unsigned int hash = resolution_errors()->compute_hash(pool, which);
  int index = resolution_errors()->hash_to_index(hash);
  {
    MutexLocker ml(SystemDictionary_lock, Thread::current());
    resolution_errors()->add_entry(index, hash, pool, which, error);
  }
}

2123 2124 2125 2126 2127
// Delete a resolution error for RedefineClasses for a constant pool is going away
void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
  resolution_errors()->delete_entry(pool);
}

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2128
// Lookup resolution error table. Returns error if found, otherwise NULL.
2129
Symbol* SystemDictionary::find_resolution_error(constantPoolHandle pool, int which) {
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2130 2131 2132 2133 2134
  unsigned int hash = resolution_errors()->compute_hash(pool, which);
  int index = resolution_errors()->hash_to_index(hash);
  {
    MutexLocker ml(SystemDictionary_lock, Thread::current());
    ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2135
    return (entry != NULL) ? entry->error() : (Symbol*)NULL;
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2136 2137 2138 2139
  }
}


2140 2141 2142 2143 2144 2145 2146 2147 2148 2149 2150 2151 2152 2153 2154 2155 2156 2157 2158 2159 2160 2161 2162 2163 2164 2165 2166 2167 2168 2169 2170 2171 2172 2173 2174 2175 2176 2177 2178 2179 2180 2181 2182 2183 2184
// Signature constraints ensure that callers and callees agree about
// the meaning of type names in their signatures.  This routine is the
// intake for constraints.  It collects them from several places:
//
//  * LinkResolver::resolve_method (if check_access is true) requires
//    that the resolving class (the caller) and the defining class of
//    the resolved method (the callee) agree on each type in the
//    method's signature.
//
//  * LinkResolver::resolve_interface_method performs exactly the same
//    checks.
//
//  * LinkResolver::resolve_field requires that the constant pool
//    attempting to link to a field agree with the field's defining
//    class about the type of the field signature.
//
//  * klassVtable::initialize_vtable requires that, when a class
//    overrides a vtable entry allocated by a superclass, that the
//    overriding method (i.e., the callee) agree with the superclass
//    on each type in the method's signature.
//
//  * klassItable::initialize_itable requires that, when a class fills
//    in its itables, for each non-abstract method installed in an
//    itable, the method (i.e., the callee) agree with the interface
//    on each type in the method's signature.
//
// All those methods have a boolean (check_access, checkconstraints)
// which turns off the checks.  This is used from specialized contexts
// such as bootstrapping, dumping, and debugging.
//
// No direct constraint is placed between the class and its
// supertypes.  Constraints are only placed along linked relations
// between callers and callees.  When a method overrides or implements
// an abstract method in a supertype (superclass or interface), the
// constraints are placed as if the supertype were the caller to the
// overriding method.  (This works well, since callers to the
// supertype have already established agreement between themselves and
// the supertype.)  As a result of all this, a class can disagree with
// its supertype about the meaning of a type name, as long as that
// class neither calls a relevant method of the supertype, nor is
// called (perhaps via an override) from the supertype.
//
//
// SystemDictionary::check_signature_loaders(sig, l1, l2)
//
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2185 2186 2187 2188
// Make sure all class components (including arrays) in the given
// signature will be resolved to the same class in both loaders.
// Returns the name of the type that failed a loader constraint check, or
// NULL if no constraint failed. The returned C string needs cleaning up
2189
// with a ResourceMark in the caller.  No exception except OOME is thrown.
2190
// Arrays are not added to the loader constraint table, their elements are.
2191
char* SystemDictionary::check_signature_loaders(Symbol* signature,
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2192 2193 2194 2195 2196 2197 2198
                                               Handle loader1, Handle loader2,
                                               bool is_method, TRAPS)  {
  // Nothing to do if loaders are the same.
  if (loader1() == loader2()) {
    return NULL;
  }

2199
  ResourceMark rm(THREAD);
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2200 2201 2202
  SignatureStream sig_strm(signature, is_method);
  while (!sig_strm.is_done()) {
    if (sig_strm.is_object()) {
2203 2204
      Symbol* s = sig_strm.as_symbol(CHECK_NULL);
      Symbol*  sig  = s;
D
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2205
      if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2206
        return sig->as_C_string();
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2207 2208 2209 2210 2211 2212 2213 2214
      }
    }
    sig_strm.next();
  }
  return NULL;
}


2215 2216 2217 2218 2219 2220 2221 2222 2223 2224 2225
methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
                                                            Symbol* signature,
                                                            TRAPS) {
  methodHandle empty;
  assert(EnableInvokeDynamic, "");
  assert(MethodHandles::is_signature_polymorphic(iid) &&
         MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
         iid != vmIntrinsics::_invokeGeneric,
         err_msg("must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid)));

  unsigned int hash  = invoke_method_table()->compute_hash(signature, iid);
2226
  int          index = invoke_method_table()->hash_to_index(hash);
2227 2228
  SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
  methodHandle m;
2229
  if (spe == NULL || spe->method() == NULL) {
2230
    spe = NULL;
2231
    // Must create lots of stuff here, but outside of the SystemDictionary lock.
2232
    m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2233 2234 2235
    CompileBroker::compile_method(m, InvocationEntryBci, CompLevel_highest_tier,
                                  methodHandle(), CompileThreshold, "MH", CHECK_(empty));

2236 2237
    // Now grab the lock.  We might have to throw away the new method,
    // if a racing thread has managed to install one at the same time.
2238 2239 2240
    {
      MutexLocker ml(SystemDictionary_lock, THREAD);
      spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2241
      if (spe == NULL)
2242
        spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2243 2244
      if (spe->method() == NULL)
        spe->set_method(m());
2245 2246 2247
    }
  }

2248 2249
  assert(spe != NULL && spe->method() != NULL, "");
  return spe->method();
2250 2251 2252 2253
}

// Helper for unpacking the return value from linkMethod and linkCallSite.
static methodHandle unpack_method_and_appendix(Handle mname,
2254
                                               KlassHandle accessing_klass,
2255 2256 2257 2258 2259
                                               objArrayHandle appendix_box,
                                               Handle* appendix_result,
                                               TRAPS) {
  methodHandle empty;
  if (mname.not_null()) {
2260
    Metadata* vmtarget = java_lang_invoke_MemberName::vmtarget(mname());
2261
    if (vmtarget != NULL && vmtarget->is_method()) {
2262
      Method* m = (Method*)vmtarget;
2263 2264 2265 2266 2267 2268 2269 2270
      oop appendix = appendix_box->obj_at(0);
      if (TraceMethodHandles) {
    #ifndef PRODUCT
        tty->print("Linked method="INTPTR_FORMAT": ", m);
        m->print();
        if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
        tty->cr();
    #endif //PRODUCT
2271
      }
2272
      (*appendix_result) = Handle(THREAD, appendix);
2273 2274 2275 2276 2277 2278
      // the target is stored in the cpCache and if a reference to this
      // MethodName is dropped we need a way to make sure the
      // class_loader containing this method is kept alive.
      // FIXME: the appendix might also preserve this dependency.
      ClassLoaderData* this_key = InstanceKlass::cast(accessing_klass())->class_loader_data();
      this_key->record_dependency(m->method_holder(), CHECK_NULL); // Can throw OOM
2279
      return methodHandle(THREAD, m);
2280 2281
    }
  }
2282 2283 2284 2285 2286 2287 2288
  THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
  return empty;
}

methodHandle SystemDictionary::find_method_handle_invoker(Symbol* name,
                                                          Symbol* signature,
                                                          KlassHandle accessing_klass,
2289 2290
                                                          Handle *appendix_result,
                                                          Handle *method_type_result,
2291 2292 2293 2294 2295 2296 2297 2298
                                                          TRAPS) {
  methodHandle empty;
  assert(EnableInvokeDynamic, "");
  assert(!THREAD->is_Compiler_thread(), "");
  Handle method_type =
    SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
  if (false) {  // FIXME: Decide if the Java upcall should resolve signatures.
    method_type = java_lang_String::create_from_symbol(signature, CHECK_(empty));
2299
  }
2300

2301
  KlassHandle  mh_klass = SystemDictionary::MethodHandle_klass();
2302 2303 2304 2305 2306 2307 2308 2309 2310 2311 2312 2313 2314 2315 2316 2317 2318 2319 2320 2321
  int ref_kind = JVM_REF_invokeVirtual;
  Handle name_str = StringTable::intern(name, CHECK_(empty));
  objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty));
  assert(appendix_box->obj_at(0) == NULL, "");

  // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
  JavaCallArguments args;
  args.push_oop(accessing_klass()->java_mirror());
  args.push_int(ref_kind);
  args.push_oop(mh_klass()->java_mirror());
  args.push_oop(name_str());
  args.push_oop(method_type());
  args.push_oop(appendix_box());
  JavaValue result(T_OBJECT);
  JavaCalls::call_static(&result,
                         SystemDictionary::MethodHandleNatives_klass(),
                         vmSymbols::linkMethod_name(),
                         vmSymbols::linkMethod_signature(),
                         &args, CHECK_(empty));
  Handle mname(THREAD, (oop) result.get_jobject());
2322
  (*method_type_result) = method_type;
2323
  return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2324 2325
}

2326

2327
// Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2328 2329 2330
// signature, as interpreted relative to the given class loader.
// Because of class loader constraints, all method handle usage must be
// consistent with this loader.
2331
Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2332
                                                 KlassHandle accessing_klass,
2333
                                                 TRAPS) {
2334 2335 2336 2337 2338
  Handle empty;
  vmIntrinsics::ID null_iid = vmIntrinsics::_none;  // distinct from all method handle invoker intrinsics
  unsigned int hash  = invoke_method_table()->compute_hash(signature, null_iid);
  int          index = invoke_method_table()->hash_to_index(hash);
  SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2339 2340 2341
  if (spe != NULL && spe->method_type() != NULL) {
    assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
    return Handle(THREAD, spe->method_type());
2342 2343 2344 2345 2346
  } else if (THREAD->is_Compiler_thread()) {
    warning("SystemDictionary::find_method_handle_type called from compiler thread");  // FIXME
    return Handle();  // do not attempt from within compiler, unless it was cached
  }

2347 2348
  Handle class_loader, protection_domain;
  bool is_on_bcp = true;  // keep this true as long as we can materialize from the boot classloader
2349
  int npts = ArgumentCount(signature).size();
2350
  objArrayHandle pts = oopFactory::new_objArray(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2351 2352
  int arg = 0;
  Handle rt;                            // the return type from the signature
2353 2354
  ResourceMark rm(THREAD);
  for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2355 2356
    oop mirror = NULL;
    if (is_on_bcp) {
2357
      // Note:  class_loader & protection_domain are both null at this point.
2358 2359 2360 2361 2362
      mirror = ss.as_java_mirror(class_loader, protection_domain,
                                 SignatureStream::ReturnNull, CHECK_(empty));
      if (mirror == NULL) {
        // fall back from BCP to accessing_klass
        if (accessing_klass.not_null()) {
2363 2364
          class_loader      = Handle(THREAD, InstanceKlass::cast(accessing_klass())->class_loader());
          protection_domain = Handle(THREAD, InstanceKlass::cast(accessing_klass())->protection_domain());
2365 2366 2367 2368 2369 2370 2371 2372
        }
        is_on_bcp = false;
      }
    }
    if (!is_on_bcp) {
      // Resolve, throwing a real error if it doesn't work.
      mirror = ss.as_java_mirror(class_loader, protection_domain,
                                 SignatureStream::NCDFError, CHECK_(empty));
2373 2374 2375 2376 2377
    }
    if (ss.at_return_type())
      rt = Handle(THREAD, mirror);
    else
      pts->obj_at_put(arg++, mirror);
2378

2379 2380
    // Check accessibility.
    if (ss.is_object() && accessing_klass.not_null()) {
2381
      Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2382
      mirror = NULL;  // safety
2383
      // Emulate ConstantPool::verify_constant_pool_resolve.
H
hseigel 已提交
2384
      if (sel_klass->oop_is_objArray())
2385
        sel_klass = ObjArrayKlass::cast(sel_klass)->bottom_klass();
H
hseigel 已提交
2386
      if (sel_klass->oop_is_instance()) {
2387 2388 2389 2390
        KlassHandle sel_kh(THREAD, sel_klass);
        LinkResolver::check_klass_accessability(accessing_klass, sel_kh, CHECK_(empty));
      }
    }
2391 2392 2393
  }
  assert(arg == npts, "");

2394
  // call java.lang.invoke.MethodHandleNatives::findMethodType(Class rt, Class[] pts) -> MethodType
2395 2396 2397 2398
  JavaCallArguments args(Handle(THREAD, rt()));
  args.push_oop(pts());
  JavaValue result(T_OBJECT);
  JavaCalls::call_static(&result,
2399 2400
                         SystemDictionary::MethodHandleNatives_klass(),
                         vmSymbols::findMethodHandleType_name(),
2401
                         vmSymbols::findMethodHandleType_signature(),
2402
                         &args, CHECK_(empty));
2403 2404
  Handle method_type(THREAD, (oop) result.get_jobject());

2405 2406 2407 2408 2409 2410
  if (is_on_bcp) {
    // We can cache this MethodType inside the JVM.
    MutexLocker ml(SystemDictionary_lock, THREAD);
    spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
    if (spe == NULL)
      spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2411 2412
    if (spe->method_type() == NULL) {
      spe->set_method_type(method_type());
2413 2414
    }
  }
2415

2416
  // report back to the caller with the MethodType
2417
  return method_type;
2418 2419
}

2420 2421 2422 2423
// Ask Java code to find or construct a method handle constant.
Handle SystemDictionary::link_method_handle_constant(KlassHandle caller,
                                                     int ref_kind, //e.g., JVM_REF_invokeVirtual
                                                     KlassHandle callee,
2424 2425
                                                     Symbol* name_sym,
                                                     Symbol* signature,
2426 2427
                                                     TRAPS) {
  Handle empty;
2428
  Handle name = java_lang_String::create_from_symbol(name_sym, CHECK_(empty));
2429 2430
  Handle type;
  if (signature->utf8_length() > 0 && signature->byte_at(0) == '(') {
2431
    type = find_method_handle_type(signature, caller, CHECK_(empty));
2432
  } else {
2433 2434
    ResourceMark rm(THREAD);
    SignatureStream ss(signature, false);
2435 2436 2437 2438 2439 2440 2441 2442 2443 2444 2445 2446
    if (!ss.is_done()) {
      oop mirror = ss.as_java_mirror(caller->class_loader(), caller->protection_domain(),
                                     SignatureStream::NCDFError, CHECK_(empty));
      type = Handle(THREAD, mirror);
      ss.next();
      if (!ss.is_done())  type = Handle();  // error!
    }
  }
  if (type.is_null()) {
    THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad signature", empty);
  }

2447
  // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2448 2449 2450 2451 2452 2453 2454 2455 2456 2457
  JavaCallArguments args;
  args.push_oop(caller->java_mirror());  // the referring class
  args.push_int(ref_kind);
  args.push_oop(callee->java_mirror());  // the target class
  args.push_oop(name());
  args.push_oop(type());
  JavaValue result(T_OBJECT);
  JavaCalls::call_static(&result,
                         SystemDictionary::MethodHandleNatives_klass(),
                         vmSymbols::linkMethodHandleConstant_name(),
2458
                         vmSymbols::linkMethodHandleConstant_signature(),
2459 2460 2461
                         &args, CHECK_(empty));
  return Handle(THREAD, (oop) result.get_jobject());
}
2462

2463
// Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2464
// name and signature, as interpreted relative to the given class loader.
2465 2466 2467 2468
methodHandle SystemDictionary::find_dynamic_call_site_invoker(KlassHandle caller,
                                                              Handle bootstrap_specifier,
                                                              Symbol* name,
                                                              Symbol* type,
2469 2470
                                                              Handle *appendix_result,
                                                              Handle *method_type_result,
2471 2472 2473 2474 2475 2476 2477 2478 2479 2480 2481 2482 2483 2484 2485 2486 2487 2488 2489
                                                              TRAPS) {
  methodHandle empty;
  Handle bsm, info;
  if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
    bsm = bootstrap_specifier;
  } else {
    assert(bootstrap_specifier->is_objArray(), "");
    objArrayHandle args(THREAD, (objArrayOop) bootstrap_specifier());
    int len = args->length();
    assert(len >= 1, "");
    bsm = Handle(THREAD, args->obj_at(0));
    if (len > 1) {
      objArrayOop args1 = oopFactory::new_objArray(SystemDictionary::Object_klass(), len-1, CHECK_(empty));
      for (int i = 1; i < len; i++)
        args1->obj_at_put(i-1, args->obj_at(i));
      info = Handle(THREAD, args1);
    }
  }
  guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2490 2491
            "caller must supply a valid BSM");

2492 2493 2494 2495 2496
  Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
  Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));

  objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty));
  assert(appendix_box->obj_at(0) == NULL, "");
2497

2498 2499 2500 2501 2502 2503
  // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, bsm, name, mtype, info, &appendix)
  JavaCallArguments args;
  args.push_oop(caller->java_mirror());
  args.push_oop(bsm());
  args.push_oop(method_name());
  args.push_oop(method_type());
2504
  args.push_oop(info());
2505
  args.push_oop(appendix_box);
2506 2507
  JavaValue result(T_OBJECT);
  JavaCalls::call_static(&result,
2508
                         SystemDictionary::MethodHandleNatives_klass(),
2509 2510
                         vmSymbols::linkCallSite_name(),
                         vmSymbols::linkCallSite_signature(),
2511
                         &args, CHECK_(empty));
2512
  Handle mname(THREAD, (oop) result.get_jobject());
2513
  (*method_type_result) = method_type;
2514
  return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
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}

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// Since the identity hash code for symbols changes when the symbols are
// moved from the regular perm gen (hash in the mark word) to the shared
// spaces (hash is the address), the classes loaded into the dictionary
// may be in the wrong buckets.

void SystemDictionary::reorder_dictionary() {
  dictionary()->reorder_dictionary();
}


void SystemDictionary::copy_buckets(char** top, char* end) {
  dictionary()->copy_buckets(top, end);
}


void SystemDictionary::copy_table(char** top, char* end) {
  dictionary()->copy_table(top, end);
}


void SystemDictionary::reverse() {
  dictionary()->reverse();
}

int SystemDictionary::number_of_classes() {
  return dictionary()->number_of_entries();
}


// ----------------------------------------------------------------------------
#ifndef PRODUCT

void SystemDictionary::print() {
  dictionary()->print();

  // Placeholders
  GCMutexLocker mu(SystemDictionary_lock);
  placeholders()->print();

  // loader constraints - print under SD_lock
  constraints()->print();
}

#endif

void SystemDictionary::verify() {
  guarantee(dictionary() != NULL, "Verify of system dictionary failed");
  guarantee(constraints() != NULL,
            "Verify of loader constraints failed");
  guarantee(dictionary()->number_of_entries() >= 0 &&
            placeholders()->number_of_entries() >= 0,
            "Verify of system dictionary failed");

  // Verify dictionary
  dictionary()->verify();

  GCMutexLocker mu(SystemDictionary_lock);
  placeholders()->verify();

  // Verify constraint table
  guarantee(constraints() != NULL, "Verify of loader constraints failed");
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  constraints()->verify(dictionary(), placeholders());
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}


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void SystemDictionary::verify_obj_klass_present(Symbol* class_name,
                                                ClassLoaderData* loader_data) {
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  GCMutexLocker mu(SystemDictionary_lock);
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  Symbol* name;

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  Klass* probe = find_class(class_name, loader_data);
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  if (probe == NULL) {
    probe = SystemDictionary::find_shared_class(class_name);
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    if (probe == NULL) {
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      name = find_placeholder(class_name, loader_data);
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    }
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  }
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  guarantee(probe != NULL || name != NULL,
            "Loaded klasses should be in SystemDictionary");
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}

#ifndef PRODUCT

// statistics code
class ClassStatistics: AllStatic {
 private:
  static int nclasses;        // number of classes
  static int nmethods;        // number of methods
  static int nmethoddata;     // number of methodData
  static int class_size;      // size of class objects in words
  static int method_size;     // size of method objects in words
  static int debug_size;      // size of debug info in methods
  static int methoddata_size; // size of methodData objects in words

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  static void do_class(Klass* k) {
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    nclasses++;
    class_size += k->size();
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    if (k->oop_is_instance()) {
      InstanceKlass* ik = (InstanceKlass*)k;
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      class_size += ik->methods()->size();
      class_size += ik->constants()->size();
      class_size += ik->local_interfaces()->size();
      class_size += ik->transitive_interfaces()->size();
      // We do not have to count implementors, since we only store one!
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      // SSS: How should these be accounted now that they have moved?
      // class_size += ik->fields()->length();
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    }
  }

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  static void do_method(Method* m) {
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    nmethods++;
    method_size += m->size();
    // class loader uses same objArray for empty vectors, so don't count these
    if (m->has_stackmap_table()) {
      method_size += m->stackmap_data()->size();
    }

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    MethodData* mdo = m->method_data();
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    if (mdo != NULL) {
      nmethoddata++;
      methoddata_size += mdo->size();
    }
  }

 public:
  static void print() {
    SystemDictionary::classes_do(do_class);
    SystemDictionary::methods_do(do_method);
    tty->print_cr("Class statistics:");
    tty->print_cr("%d classes (%d bytes)", nclasses, class_size * oopSize);
    tty->print_cr("%d methods (%d bytes = %d base + %d debug info)", nmethods,
                  (method_size + debug_size) * oopSize, method_size * oopSize, debug_size * oopSize);
    tty->print_cr("%d methoddata (%d bytes)", nmethoddata, methoddata_size * oopSize);
  }
};


int ClassStatistics::nclasses        = 0;
int ClassStatistics::nmethods        = 0;
int ClassStatistics::nmethoddata     = 0;
int ClassStatistics::class_size      = 0;
int ClassStatistics::method_size     = 0;
int ClassStatistics::debug_size      = 0;
int ClassStatistics::methoddata_size = 0;

void SystemDictionary::print_class_statistics() {
  ResourceMark rm;
  ClassStatistics::print();
}


class MethodStatistics: AllStatic {
 public:
  enum {
    max_parameter_size = 10
  };
 private:

  static int _number_of_methods;
  static int _number_of_final_methods;
  static int _number_of_static_methods;
  static int _number_of_native_methods;
  static int _number_of_synchronized_methods;
  static int _number_of_profiled_methods;
  static int _number_of_bytecodes;
  static int _parameter_size_profile[max_parameter_size];
  static int _bytecodes_profile[Bytecodes::number_of_java_codes];

  static void initialize() {
    _number_of_methods        = 0;
    _number_of_final_methods  = 0;
    _number_of_static_methods = 0;
    _number_of_native_methods = 0;
    _number_of_synchronized_methods = 0;
    _number_of_profiled_methods = 0;
    _number_of_bytecodes      = 0;
    for (int i = 0; i < max_parameter_size             ; i++) _parameter_size_profile[i] = 0;
    for (int j = 0; j < Bytecodes::number_of_java_codes; j++) _bytecodes_profile     [j] = 0;
  };

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  static void do_method(Method* m) {
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    _number_of_methods++;
    // collect flag info
    if (m->is_final()       ) _number_of_final_methods++;
    if (m->is_static()      ) _number_of_static_methods++;
    if (m->is_native()      ) _number_of_native_methods++;
    if (m->is_synchronized()) _number_of_synchronized_methods++;
    if (m->method_data() != NULL) _number_of_profiled_methods++;
    // collect parameter size info (add one for receiver, if any)
    _parameter_size_profile[MIN2(m->size_of_parameters() + (m->is_static() ? 0 : 1), max_parameter_size - 1)]++;
    // collect bytecodes info
    {
      Thread *thread = Thread::current();
      HandleMark hm(thread);
      BytecodeStream s(methodHandle(thread, m));
      Bytecodes::Code c;
      while ((c = s.next()) >= 0) {
        _number_of_bytecodes++;
        _bytecodes_profile[c]++;
      }
    }
  }

 public:
  static void print() {
    initialize();
    SystemDictionary::methods_do(do_method);
    // generate output
    tty->cr();
    tty->print_cr("Method statistics (static):");
    // flag distribution
    tty->cr();
    tty->print_cr("%6d final        methods  %6.1f%%", _number_of_final_methods       , _number_of_final_methods        * 100.0F / _number_of_methods);
    tty->print_cr("%6d static       methods  %6.1f%%", _number_of_static_methods      , _number_of_static_methods       * 100.0F / _number_of_methods);
    tty->print_cr("%6d native       methods  %6.1f%%", _number_of_native_methods      , _number_of_native_methods       * 100.0F / _number_of_methods);
    tty->print_cr("%6d synchronized methods  %6.1f%%", _number_of_synchronized_methods, _number_of_synchronized_methods * 100.0F / _number_of_methods);
    tty->print_cr("%6d profiled     methods  %6.1f%%", _number_of_profiled_methods, _number_of_profiled_methods * 100.0F / _number_of_methods);
    // parameter size profile
    tty->cr();
    { int tot = 0;
      int avg = 0;
      for (int i = 0; i < max_parameter_size; i++) {
        int n = _parameter_size_profile[i];
        tot += n;
        avg += n*i;
        tty->print_cr("parameter size = %1d: %6d methods  %5.1f%%", i, n, n * 100.0F / _number_of_methods);
      }
      assert(tot == _number_of_methods, "should be the same");
      tty->print_cr("                    %6d methods  100.0%%", _number_of_methods);
      tty->print_cr("(average parameter size = %3.1f including receiver, if any)", (float)avg / _number_of_methods);
    }
    // bytecodes profile
    tty->cr();
    { int tot = 0;
      for (int i = 0; i < Bytecodes::number_of_java_codes; i++) {
        if (Bytecodes::is_defined(i)) {
          Bytecodes::Code c = Bytecodes::cast(i);
          int n = _bytecodes_profile[c];
          tot += n;
          tty->print_cr("%9d  %7.3f%%  %s", n, n * 100.0F / _number_of_bytecodes, Bytecodes::name(c));
        }
      }
      assert(tot == _number_of_bytecodes, "should be the same");
      tty->print_cr("%9d  100.000%%", _number_of_bytecodes);
    }
    tty->cr();
  }
};

int MethodStatistics::_number_of_methods;
int MethodStatistics::_number_of_final_methods;
int MethodStatistics::_number_of_static_methods;
int MethodStatistics::_number_of_native_methods;
int MethodStatistics::_number_of_synchronized_methods;
int MethodStatistics::_number_of_profiled_methods;
int MethodStatistics::_number_of_bytecodes;
int MethodStatistics::_parameter_size_profile[MethodStatistics::max_parameter_size];
int MethodStatistics::_bytecodes_profile[Bytecodes::number_of_java_codes];


void SystemDictionary::print_method_statistics() {
  MethodStatistics::print();
}

#endif // PRODUCT