systemDictionary.cpp 119.3 KB
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/*
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 * Copyright (c) 1997, 2018, 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"
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#if INCLUDE_CDS
#include "classfile/sharedClassUtil.hpp"
#include "classfile/systemDictionaryShared.hpp"
#endif
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#include "classfile/vmSymbols.hpp"
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#include "compiler/compileBroker.hpp"
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#include "interpreter/bytecodeStream.hpp"
#include "interpreter/interpreter.hpp"
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#include "memory/filemap.hpp"
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#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"
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#include "runtime/arguments.hpp"
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#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"
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#include "runtime/orderAccess.inline.hpp"
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#include "runtime/signature.hpp"
#include "services/classLoadingService.hpp"
#include "services/threadService.hpp"
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#include "utilities/macros.hpp"
#include "utilities/ticks.hpp"
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#if INCLUDE_TRACE
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#include "trace/tracing.hpp"
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#endif

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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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  CDS_ONLY(SystemDictionaryShared::initialize(CHECK);)
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}


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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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/**
 * Returns true if the passed class loader is the extension class loader.
 */
bool SystemDictionary::is_ext_class_loader(Handle class_loader) {
  if (class_loader.is_null()) {
    return false;
  }
  return (class_loader->klass()->name() == vmSymbols::sun_misc_Launcher_ExtClassLoader());
}

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// ----------------------------------------------------------------------------
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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
524 525
  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);
527
  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.
538
  Klass* superk = SystemDictionary::resolve_super_or_fail(name,
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                                                          superclassname,
                                                          class_loader,
                                                          protection_domain,
                                                          true,
                                                          CHECK_(nh));

545 546 547
  // 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
550
    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
566
    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 {
571
      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
584
        // 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);
}


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Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
                                                        Handle class_loader,
                                                        Handle protection_domain,
                                                        TRAPS) {
606 607
  assert(name != NULL && !FieldType::is_array(name) &&
         !FieldType::is_obj(name), "invalid class name");
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609
  Ticks class_load_start_time = Ticks::now();
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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()));
614
  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
618 619 620 621
  // 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
622
  unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
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  int d_index = dictionary()->hash_to_index(d_hash);
624
  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
636
  // ParallelCapable Classloaders and the bootstrap classloader,
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  // or all classloaders with UnsyncloadClass do not acquire lock here
  bool DoObjectLock = true;
639
  if (is_parallelCapable(class_loader)) {
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    DoObjectLock = false;
  }

643
  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;
658
  Symbol* superclassname = NULL;
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  {
    MutexLocker mu(SystemDictionary_lock, THREAD);
662
    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 {
668
      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) {
672
           superclassname = placeholder->supername();
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           havesupername = true;
         }
      }
    }
  }

679
  // 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;
    }
  }

691
  bool throw_circularity_error = false;
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  if (!class_has_been_loaded) {
693
    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
699 700 701
    // 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.
717 718
    // case 5. parallelCapable user level classloaders - without objectLocker
    //    Allow parallel classloading of a class/classloader pair
719

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    {
      MutexLocker mu(SystemDictionary_lock, THREAD);
722
      if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
723
        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
743
              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
750
              oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
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            }
          }
        }
      }
755
      // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
756
      // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try
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      // LOAD_INSTANCE in parallel
758

759
      if (!throw_circularity_error && !class_has_been_loaded) {
760
        PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
761
        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
767
        // class loaders holding the ObjectLock shouldn't find the class here
768
        Klass* check = find_class(d_index, d_hash, name, loader_data);
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        if (check != NULL) {
770
        // 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;
        }
      }
    }
776

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    // must throw error outside of owning lock
    if (throw_circularity_error) {
779
      assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
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      ResourceMark rm(THREAD);
781
      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);

789
      // 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
793
      // successfully loaded InstanceKlass
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      // Should not get here for classloaders that support parallelism
795
      // with the new cleaner mechanism, even with AllowParallelDefineClass
796
      // 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
799
          && PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass())) {
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          MutexLocker mu(SystemDictionary_lock, THREAD);
801
          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,
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                              k, class_loader, THREAD);
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          }
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          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());
          }
        }
      }
835 836 837 838 839 840 841
    } // load_instance_class loop

    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);
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      placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
      SystemDictionary_lock->notify_all();
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    }
  }

847 848 849 850
  if (HAS_PENDING_EXCEPTION || k.is_null()) {
    return NULL;
  }

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  post_class_load_event(class_load_start_time, k, class_loader);

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#ifdef ASSERT
  {
855
    ClassLoaderData* loader_data = k->class_loader_data();
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    MutexLocker mu(SystemDictionary_lock, THREAD);
857
    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.
872 873
    // 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,
876
                                                 loader_data,
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                                                 protection_domain)) {
      return k();
    }
  }

  // Verify protection domain. If it fails an exception is thrown
883
  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.

900
Klass* SystemDictionary::find(Symbol* class_name,
901 902 903
                              Handle class_loader,
                              Handle protection_domain,
                              TRAPS) {
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905 906 907 908 909
  // 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()));
910 911 912 913 914 915 916
  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;
  }
917

918
  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.
926 927
    // 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;
929
    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.
937
Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
938 939 940
                                                      Handle class_loader,
                                                      Handle protection_domain,
                                                      TRAPS) {
941
  Klass* k = NULL;
942
  assert(class_name != NULL, "class name must be non NULL");
943

944
  if (FieldType::is_array(class_name)) {
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    // The name refers to an array.  Parse the name.
946 947 948 949
    // 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 {
953
      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?
967
Klass* SystemDictionary::parse_stream(Symbol* class_name,
968 969 970 971 972 973
                                      Handle class_loader,
                                      Handle protection_domain,
                                      ClassFileStream* st,
                                      KlassHandle host_klass,
                                      GrowableArray<Handle>* cp_patches,
                                      TRAPS) {
974
  TempNewSymbol parsed_name = NULL;
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976
  Ticks class_load_start_time = Ticks::now();
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978 979 980 981 982 983
  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");
984
    guarantee(!DumpSharedSpaces, "must not create anonymous classes when dumping");
985 986 987 988 989 990
    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,
998
                                                             loader_data,
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                                                             protection_domain,
1000 1001
                                                             host_klass,
                                                             cp_patches,
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                                                             parsed_name,
1003
                                                             true,
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                                                             THREAD);


1007
  if (host_klass.not_null() && k.not_null()) {
1008
    assert(EnableInvokeDynamic, "");
1009
    // If it's anonymous, initialize it now, since nobody else will.
1010 1011 1012 1013 1014 1015 1016 1017 1018

    {
      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.
1019 1020 1021

      // compiled code dependencies need to be validated anyway
      notice_modification();
1022 1023
    }

1024
    // Rewrite and patch constant pool here.
1025
    k->link_class(CHECK_NULL);
1026 1027 1028
    if (cp_patches != NULL) {
      k->constants()->patch_resolved_references(cp_patches);
    }
1029
    k->eager_initialize(CHECK_NULL);
1030 1031 1032 1033 1034 1035

    // notify jvmti
    if (JvmtiExport::should_post_class_load()) {
        assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
        JvmtiExport::post_class_load((JavaThread *) THREAD, k());
    }
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    post_class_load_event(class_load_start_time, k, class_loader);
1038
  }
1039 1040
  assert(host_klass.not_null() || cp_patches == NULL,
         "cp_patches only found with host_klass");
1041

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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.

1050
Klass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1051 1052 1053 1054 1055
                                             Handle class_loader,
                                             Handle protection_domain,
                                             ClassFileStream* st,
                                             bool verify,
                                             TRAPS) {
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1057 1058 1059 1060 1061 1062 1063
  // 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;
  }

1064
  ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL);
1065

1066
  // 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);
1069
  ObjectLocker ol(lockObject, THREAD, DoObjectLock);
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1071
  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,
1080
                                                             loader_data,
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                                                             protection_domain,
                                                             parsed_name,
1083
                                                             verify,
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                                                             THREAD);

  const char* pkg = "java/";
1087
  size_t pkglen = strlen(pkg);
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  if (!HAS_PENDING_EXCEPTION &&
      !class_loader.is_null() &&
1090
      parsed_name != NULL &&
1091 1092
      parsed_name->utf8_length() >= (int)pkglen &&
      !strncmp((const char*)parsed_name->bytes(), pkg, pkglen)) {
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    // 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, '/');
1098
    assert(index != NULL, "must be");
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    *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) {
1112 1113
    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
1120
    // If a class loader supports parallel classloading handle parallel define requests
1121
    // find_or_define_instance_class may return a different InstanceKlass
1122 1123 1124 1125 1126
    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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  }

1129
  // Make sure we have an entry in the SystemDictionary on success
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  debug_only( {
    if (!HAS_PENDING_EXCEPTION) {
1132 1133
      assert(parsed_name != NULL, "parsed_name is still null?");
      Symbol*  h_name    = k->name();
1134
      ClassLoaderData *defining_loader_data = k->class_loader_data();
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      MutexLocker mu(SystemDictionary_lock, THREAD);

1138
      Klass* check = find_class(parsed_name, loader_data);
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      assert(check == k(), "should be present in the dictionary");

1141
      Klass* check2 = find_class(h_name, defining_loader_data);
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      assert(check == check2, "name inconsistancy in SystemDictionary");
    }
  } );

  return k();
}

1149
#if INCLUDE_CDS
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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.

1161
Klass* SystemDictionary::find_shared_class(Symbol* class_name) {
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  if (shared_dictionary() != NULL) {
1163
    unsigned int d_hash = shared_dictionary()->compute_hash(class_name, NULL);
1164
    int d_index = shared_dictionary()->hash_to_index(d_hash);
1165

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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(
1180
                 Symbol* class_name, Handle class_loader, TRAPS) {
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  instanceKlassHandle ik (THREAD, find_shared_class(class_name));
1182 1183 1184 1185 1186 1187 1188
  // Make sure we only return the boot class for the NULL classloader.
  if (ik.not_null() &&
      SharedClassUtil::is_shared_boot_class(ik()) && class_loader.is_null()) {
    Handle protection_domain;
    return load_shared_class(ik, class_loader, protection_domain, THREAD);
  }
  return instanceKlassHandle();
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}

1191 1192 1193
instanceKlassHandle SystemDictionary::load_shared_class(instanceKlassHandle ik,
                                                        Handle class_loader,
                                                        Handle protection_domain, TRAPS) {
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  if (ik.not_null()) {
    instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1196
    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) {
1203
      Symbol*  cn = ik->super()->name();
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      Klass *s = resolve_super_or_fail(class_name, cn,
                                       class_loader, protection_domain, true, CHECK_(nh));
      if (s != ik->super()) {
        // The dynamically resolved super class is not the same as the one we used during dump time,
        // so we cannot use ik.
        return nh;
      }
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    }

1213
    Array<Klass*>* interfaces = ik->local_interfaces();
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    int num_interfaces = interfaces->length();
    for (int index = 0; index < num_interfaces; index++) {
1216
      Klass* k = interfaces->at(index);
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1218 1219
      // 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)
1222
      Symbol*  name  = k->name();
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      Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_(nh));
      if (k != i) {
        // The dynamically resolved interface class is not the same as the one we used during dump time,
        // so we cannot use ik.
        return nh;
      }
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    }

    // 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
1237 1238 1239 1240
    //
    // Shared classes are all currently loaded by either the bootstrap or
    // internal parallel class loaders, so this will never cause a deadlock
    // on a custom class loader lock.
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1242
    ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
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    {
      Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
      check_loader_lock_contention(lockObject, THREAD);
      ObjectLocker ol(lockObject, THREAD, true);
1247
      ik->restore_unshareable_info(loader_data, protection_domain, CHECK_(nh));
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    }

    if (TraceClassLoading) {
      ResourceMark rm;
      tty->print("[Loaded %s", ik->external_name());
      tty->print(" from shared objects file");
1254 1255 1256
      if (class_loader.not_null()) {
        tty->print(" by %s", loader_data->loader_name());
      }
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      tty->print_cr("]");
    }
1259 1260 1261 1262 1263 1264 1265 1266 1267 1268

    if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
      // Only dump the classes that can be stored into CDS archive
      if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
        ResourceMark rm(THREAD);
        classlist_file->print_cr("%s", ik->name()->as_C_string());
        classlist_file->flush();
      }
    }

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    // notify a class loaded from shared object
1270
    ClassLoadingService::notify_class_loaded(InstanceKlass::cast(ik()),
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                                             true /* shared class */);
  }
  return ik;
}
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#endif // INCLUDE_CDS
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1277
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()) {
1280

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    // Search the shared system dictionary for classes preloaded into the
    // shared spaces.
    instanceKlassHandle k;
1284
    {
1285
#if INCLUDE_CDS
1286 1287
      PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
      k = load_shared_class(class_name, class_loader, THREAD);
1288
#endif
1289
    }
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    if (k.is_null()) {
      // Use VM class loader
1293
      PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
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      k = ClassLoader::load_classfile(class_name, CHECK_(nh));
    }

1297
    // 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);

1306 1307 1308 1309 1310 1311 1312 1313 1314 1315
    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);

1322
    KlassHandle spec_klass (THREAD, SystemDictionary::ClassLoader_klass());
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1324 1325 1326 1327 1328 1329 1330 1331 1332 1333
    // 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
1336
    // 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.
1338 1339 1340 1341
    //
    // 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,
1345 1346
                              vmSymbols::loadClassInternal_name(),
                              vmSymbols::string_class_signature(),
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                              string,
                              CHECK_(nh));
    } else {
      JavaCalls::call_virtual(&result,
                              class_loader,
                              spec_klass,
1353 1354
                              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 =
1366
                instanceKlassHandle(THREAD, java_lang_Class::as_Klass(obj));
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1367 1368 1369
      // 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.
1370
      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) {

1381 1382 1383 1384
  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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1386 1387 1388 1389 1390 1391
 // 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
1406
  Symbol*  name_h = k->name();
1407
  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);

1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423
  // 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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1424 1425
  // Add the new class. We need recompile lock during update of CHA.
  {
1426
    unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
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1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447
    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());

  }
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1449 1450 1451
}

// Support parallel classloading
1452 1453 1454
// 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
1455 1456
// With AllowParallelDefine flag==true, in case they do not synchronize around
// FindLoadedClass/DefineClass, calls, we check for parallel
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1457 1458
// loading for them, wait if a defineClass is in progress
// and return the initial requestor's results
1459
// This flag does not apply to the bootstrap classloader.
1460 1461
// With AllowParallelDefine flag==false, call through to define_instance_class
// which will throw LinkageError: duplicate class definition.
1462
// False is the requested default.
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// For better performance, the class loaders should synchronize
1464
// findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
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1465 1466
// potentially waste time reading and parsing the bytestream.
// Note: VM callers should ensure consistency of k/class_name,class_loader
1467
instanceKlassHandle SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader, instanceKlassHandle k, TRAPS) {
D
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1468 1469

  instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1470
  Symbol*  name_h = k->name(); // passed in class_name may be null
1471
  ClassLoaderData* loader_data = class_loader_data(class_loader);
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1473
  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
1477
  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
1484
    if (UnsyncloadClass || (is_parallelDefine(class_loader))) {
1485
      Klass* check = find_class(d_index, d_hash, name_h, loader_data);
1486 1487 1488
      if (check != NULL) {
        return(instanceKlassHandle(THREAD, check));
      }
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    }

    // Acquire define token for this class/classloader
1492
    probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1493 1494 1495 1496 1497 1498 1499 1500 1501 1502
    // 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)) {
1504
        placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1505
        SystemDictionary_lock->notify_all();
D
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#ifdef ASSERT
1507
        Klass* check = find_class(d_index, d_hash, name_h, loader_data);
1508
        assert(check != NULL, "definer missed recording success");
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#endif
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        return(instanceKlassHandle(THREAD, probe->instance_klass()));
1511 1512 1513
    } 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);
1524
    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);
1534
      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

1581
Klass* SystemDictionary::find_class(int index, unsigned int hash,
1582
                                      Symbol* class_name,
1583
                                      ClassLoaderData* loader_data) {
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  assert_locked_or_safepoint(SystemDictionary_lock);
1585
  assert (index == dictionary()->index_for(class_name, loader_data),
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          "incorrect index?");

1588
  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
1594
Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1595
                                           ClassLoaderData* loader_data) {
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  assert_locked_or_safepoint(SystemDictionary_lock);
1597
  unsigned int p_hash = placeholders()->compute_hash(class_name, loader_data);
1598
  int p_index = placeholders()->hash_to_index(p_hash);
1599
  return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
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}


// Used for assertions and verification only
1604
Klass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
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  #ifndef ASSERT
1606 1607 1608 1609
  guarantee(VerifyBeforeGC      ||
            VerifyDuringGC      ||
            VerifyBeforeExit    ||
            VerifyDuringStartup ||
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            VerifyAfterGC, "too expensive");
  #endif
  assert_locked_or_safepoint(SystemDictionary_lock);

  // First look in the loaded class array
1615
  unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
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  int d_index = dictionary()->hash_to_index(d_hash);
1617
  return find_class(d_index, d_hash, class_name, loader_data);
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}


// Get the next class in the diictionary.
1622
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");
1634 1635
  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
1639
  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) {
1659
  roots_oops_do(blk, NULL);
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}

1662 1663 1664
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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1666 1667
  // Placeholders. These represent classes we're actively loading.
  placeholders()->classes_do(closure);
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}

1670 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682 1683 1684
// 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;
}
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1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703
#ifdef ASSERT
class VerifySDReachableAndLiveClosure : public OopClosure {
private:
  BoolObjectClosure* _is_alive;

  template <class T> void do_oop_work(T* p) {
    oop obj = oopDesc::load_decode_heap_oop(p);
    guarantee(_is_alive->do_object_b(obj), "Oop in system dictionary must be live");
  }

public:
  VerifySDReachableAndLiveClosure(BoolObjectClosure* is_alive) : OopClosure(), _is_alive(is_alive) { }

  virtual void do_oop(oop* p)       { do_oop_work(p); }
  virtual void do_oop(narrowOop* p) { do_oop_work(p); }
};
#endif

1704 1705
// Assumes classes in the SystemDictionary are only unloaded at a safepoint
// Note: anonymous classes are not in the SD.
1706
bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive, bool clean_alive) {
1707
  // First, mark for unload all ClassLoaderData referencing a dead class loader.
1708
  bool unloading_occurred = ClassLoaderDataGraph::do_unloading(is_alive, clean_alive);
1709 1710
  if (unloading_occurred) {
    dictionary()->do_unloading();
1711 1712
    constraints()->purge_loader_constraints();
    resolution_errors()->purge_resolution_errors();
1713 1714 1715 1716 1717 1718 1719 1720 1721
  }
  // Oops referenced by the system dictionary may get unreachable independently
  // of the class loader (eg. cached protection domain oops). So we need to
  // explicitly unlink them here instead of in Dictionary::do_unloading.
  dictionary()->unlink(is_alive);
#ifdef ASSERT
  VerifySDReachableAndLiveClosure cl(is_alive);
  dictionary()->oops_do(&cl);
#endif
1722
  return unloading_occurred;
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}

1725 1726 1727
void SystemDictionary::roots_oops_do(OopClosure* strong, OopClosure* weak) {
  strong->do_oop(&_java_system_loader);
  strong->do_oop(&_system_loader_lock_obj);
1728
  CDS_ONLY(SystemDictionaryShared::roots_oops_do(strong);)
1729 1730 1731 1732 1733 1734 1735 1736

  // Adjust dictionary
  dictionary()->roots_oops_do(strong, weak);

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

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void SystemDictionary::oops_do(OopClosure* f) {
  f->do_oop(&_java_system_loader);
1739
  f->do_oop(&_system_loader_lock_obj);
1740
  CDS_ONLY(SystemDictionaryShared::oops_do(f);)
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  // Adjust dictionary
  dictionary()->oops_do(f);

1745
  // Visit extra methods
1746
  invoke_method_table()->oops_do(f);
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}

1749 1750 1751 1752 1753
// 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) {
1754
  for (int k = (int)FIRST_WKID; k < (int)WKID_LIMIT; k++) {
1755
    f->do_klass(_well_known_klasses[k]);
1756 1757
  }

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  {
    for (int i = 0; i < T_VOID+1; i++) {
      if (_box_klasses[i] != NULL) {
        assert(i >= T_BOOLEAN, "checking");
1762
        f->do_klass(_box_klasses[i]);
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      }
    }
  }

1767
  FilteredFieldsMap::classes_do(f);
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}

1770 1771
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
1776
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
1783
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
1789
void SystemDictionary::classes_do(void f(Klass*, ClassLoaderData*)) {
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  dictionary()->classes_do(f);
}

1793
void SystemDictionary::placeholders_do(void f(Symbol*)) {
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  placeholders()->entries_do(f);
}

1797
void SystemDictionary::methods_do(void f(Method*)) {
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  dictionary()->methods_do(f);
1799
  invoke_method_table()->methods_do(f);
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}

1802 1803 1804 1805
void SystemDictionary::remove_classes_in_error_state() {
  dictionary()->remove_classes_in_error_state();
}

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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.
1815
  Klass* aos = _abstract_ownable_synchronizer_klass;
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  if (aos == NULL) {
1817
    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");
1831 1832
  _sdgeneration        = 0;
  _dictionary          = new Dictionary(calculate_systemdictionary_size(PredictedLoadedClassCount));
1833
  _placeholders        = new PlaceholderTable(_nof_buckets);
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  _number_of_modifications = 0;
1835 1836 1837
  _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
1840
  _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
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  // Initialize basic classes
  initialize_preloaded_classes(CHECK);
}

1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859
// 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);
1860
  Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
1861
  Klass**    klassp = &_well_known_klasses[id];
1862
  bool must_load = (init_opt < SystemDictionary::Opt);
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  if ((*klassp) == NULL) {
1864 1865 1866 1867 1868 1869
    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
    }
  }
1870
  return ((*klassp) != NULL);
1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 1881 1882
}

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);
  }
1883 1884 1885

  // move the starting value forward to the limit:
  start_id = limit_id;
1886 1887
}

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void SystemDictionary::initialize_preloaded_classes(TRAPS) {
1889
  assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
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  // Preload commonly used klasses
1891
  WKID scan = FIRST_WKID;
1892 1893 1894 1895 1896 1897
  // 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);
1898
    initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1899 1900 1901
  } else {
    initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
  }
1902

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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();
1906
  java_lang_Class::compute_offsets();
1907

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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);

1916
  // do a bunch more:
1917
  initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
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  // Preload ref klasses and set reference types
1920
  InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
1921
  InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
1922

1923
  initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Cleaner_klass), scan, CHECK);
1924 1925 1926 1927
  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);
1928
  InstanceKlass::cast(WK_KLASS(Cleaner_klass))->set_reference_type(REF_CLEANER);
1929

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  initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(ReferenceQueue_klass), scan, CHECK);

1932 1933
  // JSR 292 classes
  WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
1934
  WKID jsr292_group_end   = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
1935
  initialize_wk_klasses_until(jsr292_group_start, scan, CHECK);
1936
  if (EnableInvokeDynamic) {
1937 1938 1939 1940
    initialize_wk_klasses_through(jsr292_group_end, scan, CHECK);
  } else {
    // Skip the JSR 292 classes, if not enabled.
    scan = WKID(jsr292_group_end + 1);
1941
  }
1942

1943 1944
  initialize_wk_klasses_until(WKID_LIMIT, scan, CHECK);

1945 1946 1947 1948 1949 1950 1951 1952
  _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);
1953 1954 1955
  //_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.
1957
    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
1961
    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.
1968
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
1983
// 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;
  {
1991
    Symbol*  name  = k->name();
1992 1993
    ClassLoaderData *loader_data = class_loader_data(class_loader);

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    MutexLocker mu(SystemDictionary_lock, THREAD);

1996 1997 1998
    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

2004
      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
2014
    Symbol* ph_check = find_placeholder(name, loader_data);
2015
    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);
2051
  Symbol*  name  = k->name();
2052
  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
2062
  // 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());
    }
  }

2077
  // Make a new system dictionary entry.
2078
  Klass* sd_check = find_class(d_index, d_hash, name, loader_data);
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  if (sd_check == NULL) {
2080
    dictionary()->add_klass(name, loader_data, k);
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    notice_modification();
  }
#ifdef ASSERT
2084
  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");
2086 2087
  // Note: there may be a placeholder entry: for circularity testing
  // or for parallel defines
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#endif
    SystemDictionary_lock->notify_all();
  }
}


2094 2095 2096
// 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.
2097
Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2098
                    Symbol* class_name, Handle class_loader, TRAPS) {
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  // First see if it has been loaded directly.
  // Force the protection domain to be null.  (This removes protection checks.)
  Handle no_protection_domain;
2103
  Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2104
                                              no_protection_domain, CHECK_NULL);
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  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.
2111
  if (FieldType::is_array(class_name)) {
2112 2113
    // For array classes, their Klass*s are not kept in the
    // constraint table. The element Klass*s are.
2114 2115
    FieldArrayInfo fd;
    BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
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    if (t != T_OBJECT) {
      klass = Universe::typeArrayKlassObj(t);
    } else {
      MutexLocker mu(SystemDictionary_lock, THREAD);
2120
      klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
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    }
2122
    // If element class already loaded, allocate array klass
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    if (klass != NULL) {
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2124
      klass = klass->array_klass_or_null(fd.dimension());
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    }
  } 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;
}


2136
bool SystemDictionary::add_loader_constraint(Symbol* class_name,
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                                             Handle class_loader1,
                                             Handle class_loader2,
                                             Thread* THREAD) {
2140 2141 2142
  ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
  ClassLoaderData* loader_data2 = class_loader_data(class_loader2);

2143 2144
  Symbol* constraint_name = NULL;
  if (!FieldType::is_array(class_name)) {
2145 2146
    constraint_name = class_name;
  } else {
2147
    // For array classes, their Klass*s are not kept in the
2148
    // constraint table. The element classes are.
2149 2150
    FieldArrayInfo fd;
    BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2151 2152 2153 2154
    // primitive types always pass
    if (t != T_OBJECT) {
      return true;
    } else {
2155
      constraint_name = fd.object_key();
2156 2157
    }
  }
2158
  unsigned int d_hash1 = dictionary()->compute_hash(constraint_name, loader_data1);
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  int d_index1 = dictionary()->hash_to_index(d_hash1);

2161
  unsigned int d_hash2 = dictionary()->compute_hash(constraint_name, loader_data2);
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  int d_index2 = dictionary()->hash_to_index(d_hash2);
  {
2164
  MutexLocker mu_s(SystemDictionary_lock, THREAD);
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2166 2167
  // Better never do a GC while we're holding these oops
  No_Safepoint_Verifier nosafepoint;
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2169 2170
  Klass* klass1 = find_class(d_index1, d_hash1, constraint_name, loader_data1);
  Klass* klass2 = find_class(d_index2, d_hash2, constraint_name, loader_data2);
2171 2172
  return constraints()->add_entry(constraint_name, klass1, class_loader1,
                                  klass2, class_loader2);
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  }
}

// Add entry to resolution error table to record the error when the first
// attempt to resolve a reference to a class has failed.
2178
void SystemDictionary::add_resolution_error(constantPoolHandle pool, int which, Symbol* error) {
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  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);
  }
}

2187 2188 2189 2190 2191
// 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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2192
// Lookup resolution error table. Returns error if found, otherwise NULL.
2193
Symbol* SystemDictionary::find_resolution_error(constantPoolHandle pool, int which) {
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  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);
2199
    return (entry != NULL) ? entry->error() : (Symbol*)NULL;
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  }
}


2204 2205 2206 2207 2208 2209 2210 2211 2212 2213 2214 2215 2216 2217 2218 2219 2220 2221 2222 2223 2224 2225 2226 2227 2228 2229 2230 2231 2232 2233 2234 2235 2236 2237 2238 2239 2240 2241 2242 2243 2244 2245 2246 2247 2248
// 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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// 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
2252
// NULL if no constraint failed.  No exception except OOME is thrown.
2253
// Arrays are not added to the loader constraint table, their elements are.
2254
Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
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2255 2256 2257 2258 2259 2260 2261 2262 2263 2264
                                               Handle loader1, Handle loader2,
                                               bool is_method, TRAPS)  {
  // Nothing to do if loaders are the same.
  if (loader1() == loader2()) {
    return NULL;
  }

  SignatureStream sig_strm(signature, is_method);
  while (!sig_strm.is_done()) {
    if (sig_strm.is_object()) {
2265
      Symbol* sig = sig_strm.as_symbol(CHECK_NULL);
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2266
      if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2267
        return sig;
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      }
    }
    sig_strm.next();
  }
  return NULL;
}


2276 2277 2278 2279 2280 2281 2282 2283 2284 2285 2286
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);
2287
  int          index = invoke_method_table()->hash_to_index(hash);
2288 2289
  SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
  methodHandle m;
2290
  if (spe == NULL || spe->method() == NULL) {
2291
    spe = NULL;
2292
    // Must create lots of stuff here, but outside of the SystemDictionary lock.
2293
    m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2294 2295 2296 2297 2298 2299 2300 2301
    if (!Arguments::is_interpreter_only()) {
      // Generate a compiled form of the MH intrinsic.
      AdapterHandlerLibrary::create_native_wrapper(m);
      // Check if have the compiled code.
      if (!m->has_compiled_code()) {
        THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(),
                   "out of space in CodeCache for method handle intrinsic", empty);
      }
2302
    }
2303 2304
    // 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.
2305 2306 2307
    {
      MutexLocker ml(SystemDictionary_lock, THREAD);
      spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2308
      if (spe == NULL)
2309
        spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2310 2311
      if (spe->method() == NULL)
        spe->set_method(m());
2312 2313 2314
    }
  }

2315
  assert(spe != NULL && spe->method() != NULL, "");
2316
  assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2317 2318
         spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
         "MH intrinsic invariant");
2319
  return spe->method();
2320 2321 2322 2323
}

// Helper for unpacking the return value from linkMethod and linkCallSite.
static methodHandle unpack_method_and_appendix(Handle mname,
2324
                                               KlassHandle accessing_klass,
2325 2326 2327 2328 2329
                                               objArrayHandle appendix_box,
                                               Handle* appendix_result,
                                               TRAPS) {
  methodHandle empty;
  if (mname.not_null()) {
2330
    Metadata* vmtarget = java_lang_invoke_MemberName::vmtarget(mname());
2331
    if (vmtarget != NULL && vmtarget->is_method()) {
2332
      Method* m = (Method*)vmtarget;
2333 2334 2335
      oop appendix = appendix_box->obj_at(0);
      if (TraceMethodHandles) {
    #ifndef PRODUCT
2336
        tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2337 2338 2339 2340
        m->print();
        if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
        tty->cr();
    #endif //PRODUCT
2341
      }
2342
      (*appendix_result) = Handle(THREAD, appendix);
2343 2344 2345 2346 2347 2348
      // 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
2349
      return methodHandle(THREAD, m);
2350 2351
    }
  }
2352 2353 2354 2355 2356 2357 2358
  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,
2359 2360
                                                          Handle *appendix_result,
                                                          Handle *method_type_result,
2361 2362 2363 2364 2365 2366 2367
                                                          TRAPS) {
  methodHandle empty;
  assert(EnableInvokeDynamic, "");
  assert(!THREAD->is_Compiler_thread(), "");
  Handle method_type =
    SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));

2368
  KlassHandle  mh_klass = SystemDictionary::MethodHandle_klass();
2369 2370 2371 2372 2373
  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, "");

2374 2375 2376 2377 2378
  // This should not happen.  JDK code should take care of that.
  if (accessing_klass.is_null() || method_type.is_null()) {
    THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
  }

2379 2380 2381 2382 2383 2384 2385 2386 2387 2388 2389 2390 2391 2392 2393
  // 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());
2394
  (*method_type_result) = method_type;
2395
  return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2396 2397
}

2398 2399 2400 2401 2402 2403 2404 2405 2406 2407 2408 2409 2410 2411 2412 2413 2414 2415
// Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
// We must ensure that all class loaders everywhere will reach this class, for any client.
// This is a safe bet for public classes in java.lang, such as Object and String.
// We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
// Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
static bool is_always_visible_class(oop mirror) {
  Klass* klass = java_lang_Class::as_Klass(mirror);
  if (klass->oop_is_objArray()) {
    klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
  }
  if (klass->oop_is_typeArray()) {
    return true; // primitive array
  }
  assert(klass->oop_is_instance(), klass->external_name());
  return klass->is_public() &&
         (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) ||       // java.lang
          InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass()));  // java.lang.invoke
}
2416

2417
// Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2418 2419 2420
// signature, as interpreted relative to the given class loader.
// Because of class loader constraints, all method handle usage must be
// consistent with this loader.
2421
Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2422
                                                 KlassHandle accessing_klass,
2423
                                                 TRAPS) {
2424 2425 2426 2427 2428
  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);
2429 2430 2431
  if (spe != NULL && spe->method_type() != NULL) {
    assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
    return Handle(THREAD, spe->method_type());
2432 2433 2434 2435 2436
  } 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
  }

2437
  Handle class_loader, protection_domain;
2438 2439 2440 2441 2442
  if (accessing_klass.not_null()) {
    class_loader      = Handle(THREAD, InstanceKlass::cast(accessing_klass())->class_loader());
    protection_domain = Handle(THREAD, InstanceKlass::cast(accessing_klass())->protection_domain());
  }
  bool can_be_cached = true;
2443
  int npts = ArgumentCount(signature).size();
2444
  objArrayHandle pts = oopFactory::new_objArray(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2445
  int arg = 0;
2446
  Handle rt; // the return type from the signature
2447 2448
  ResourceMark rm(THREAD);
  for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2449
    oop mirror = NULL;
2450 2451 2452
    if (can_be_cached) {
      // Use neutral class loader to lookup candidate classes to be placed in the cache.
      mirror = ss.as_java_mirror(Handle(), Handle(),
2453
                                 SignatureStream::ReturnNull, CHECK_(empty));
2454 2455 2456
      if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) {
        // Fall back to accessing_klass context.
        can_be_cached = false;
2457 2458
      }
    }
2459
    if (!can_be_cached) {
2460 2461 2462
      // Resolve, throwing a real error if it doesn't work.
      mirror = ss.as_java_mirror(class_loader, protection_domain,
                                 SignatureStream::NCDFError, CHECK_(empty));
2463
    }
2464
    assert(!oopDesc::is_null(mirror), ss.as_symbol(THREAD)->as_C_string());
2465 2466 2467 2468
    if (ss.at_return_type())
      rt = Handle(THREAD, mirror);
    else
      pts->obj_at_put(arg++, mirror);
2469

2470 2471
    // Check accessibility.
    if (ss.is_object() && accessing_klass.not_null()) {
2472
      Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2473
      mirror = NULL;  // safety
2474
      // Emulate ConstantPool::verify_constant_pool_resolve.
H
hseigel 已提交
2475
      if (sel_klass->oop_is_objArray())
2476
        sel_klass = ObjArrayKlass::cast(sel_klass)->bottom_klass();
H
hseigel 已提交
2477
      if (sel_klass->oop_is_instance()) {
2478 2479 2480 2481
        KlassHandle sel_kh(THREAD, sel_klass);
        LinkResolver::check_klass_accessability(accessing_klass, sel_kh, CHECK_(empty));
      }
    }
2482 2483 2484
  }
  assert(arg == npts, "");

2485
  // call java.lang.invoke.MethodHandleNatives::findMethodType(Class rt, Class[] pts) -> MethodType
2486 2487 2488 2489
  JavaCallArguments args(Handle(THREAD, rt()));
  args.push_oop(pts());
  JavaValue result(T_OBJECT);
  JavaCalls::call_static(&result,
2490 2491
                         SystemDictionary::MethodHandleNatives_klass(),
                         vmSymbols::findMethodHandleType_name(),
2492
                         vmSymbols::findMethodHandleType_signature(),
2493
                         &args, CHECK_(empty));
2494 2495
  Handle method_type(THREAD, (oop) result.get_jobject());

2496
  if (can_be_cached) {
2497 2498 2499 2500 2501
    // 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);
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    if (spe->method_type() == NULL) {
      spe->set_method_type(method_type());
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    }
  }
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  // report back to the caller with the MethodType
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  return method_type;
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}

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// 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,
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                                                     Symbol* name_sym,
                                                     Symbol* signature,
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                                                     TRAPS) {
  Handle empty;
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  Handle name = java_lang_String::create_from_symbol(name_sym, CHECK_(empty));
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  Handle type;
  if (signature->utf8_length() > 0 && signature->byte_at(0) == '(') {
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    type = find_method_handle_type(signature, caller, CHECK_(empty));
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  } else if (caller.is_null()) {
    // This should not happen.  JDK code should take care of that.
    THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
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  } else {
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    ResourceMark rm(THREAD);
    SignatureStream ss(signature, false);
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    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);
  }

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  // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
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  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(),
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                         vmSymbols::linkMethodHandleConstant_signature(),
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                         &args, CHECK_(empty));
  return Handle(THREAD, (oop) result.get_jobject());
}
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// Ask Java code to find or construct a java.lang.invoke.CallSite for the given
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// name and signature, as interpreted relative to the given class loader.
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methodHandle SystemDictionary::find_dynamic_call_site_invoker(KlassHandle caller,
                                                              Handle bootstrap_specifier,
                                                              Symbol* name,
                                                              Symbol* type,
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                                                              Handle *appendix_result,
                                                              Handle *method_type_result,
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                                                              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()),
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            "caller must supply a valid BSM");

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  Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
  Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));

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  // This should not happen.  JDK code should take care of that.
  if (caller.is_null() || method_type.is_null()) {
    THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty);
  }

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  objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty));
  assert(appendix_box->obj_at(0) == NULL, "");
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  // 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());
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  args.push_oop(info());
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  args.push_oop(appendix_box);
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  JavaValue result(T_OBJECT);
  JavaCalls::call_static(&result,
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                         SystemDictionary::MethodHandleNatives_klass(),
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                         vmSymbols::linkCallSite_name(),
                         vmSymbols::linkCallSite_signature(),
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                         &args, CHECK_(empty));
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  Handle mname(THREAD, (oop) result.get_jobject());
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  (*method_type_result) = method_type;
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  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();
}


// ----------------------------------------------------------------------------
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void SystemDictionary::print_shared(bool details) {
  shared_dictionary()->print(details);
}
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void SystemDictionary::print(bool details) {
  dictionary()->print(details);
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  // Placeholders
  GCMutexLocker mu(SystemDictionary_lock);
  placeholders()->print();

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


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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// utility function for class load event
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void SystemDictionary::post_class_load_event(const Ticks& start_time,
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                                             instanceKlassHandle k,
                                             Handle initiating_loader) {
#if INCLUDE_TRACE
  EventClassLoad event(UNTIMED);
  if (event.should_commit()) {
    event.set_starttime(start_time);
    event.set_loadedClass(k());
    oop defining_class_loader = k->class_loader();
    event.set_definingClassLoader(defining_class_loader !=  NULL ?
                                    defining_class_loader->klass() : (Klass*)NULL);
    oop class_loader = initiating_loader.is_null() ? (oop)NULL : initiating_loader();
    event.set_initiatingClassLoader(class_loader != NULL ?
                                      class_loader->klass() : (Klass*)NULL);
    event.commit();
  }
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#endif // INCLUDE_TRACE
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}

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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