view src/share/vm/memory/universe.cpp @ 453:c96030fff130

6684579: SoftReference processing can be made more efficient Summary: For current soft-ref clearing policies, we can decide at marking time if a soft-reference will definitely not be cleared, postponing the decision of whether it will definitely be cleared to the final reference processing phase. This can be especially beneficial in the case of concurrent collectors where the marking is usually concurrent but reference processing is usually not. Reviewed-by: jmasa
author ysr
date Thu, 20 Nov 2008 16:56:09 -0800
parents 1ee8caae33af
children 7d7a7c599c17
line wrap: on
line source
/*
 * Copyright 1997-2008 Sun Microsystems, Inc.  All Rights Reserved.
 * 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.
 *
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 *
 */

# include "incls/_precompiled.incl"
# include "incls/_universe.cpp.incl"

// Known objects
klassOop Universe::_boolArrayKlassObj                 = NULL;
klassOop Universe::_byteArrayKlassObj                 = NULL;
klassOop Universe::_charArrayKlassObj                 = NULL;
klassOop Universe::_intArrayKlassObj                  = NULL;
klassOop Universe::_shortArrayKlassObj                = NULL;
klassOop Universe::_longArrayKlassObj                 = NULL;
klassOop Universe::_singleArrayKlassObj               = NULL;
klassOop Universe::_doubleArrayKlassObj               = NULL;
klassOop Universe::_typeArrayKlassObjs[T_VOID+1]      = { NULL /*, NULL...*/ };
klassOop Universe::_objectArrayKlassObj               = NULL;
klassOop Universe::_symbolKlassObj                    = NULL;
klassOop Universe::_methodKlassObj                    = NULL;
klassOop Universe::_constMethodKlassObj               = NULL;
klassOop Universe::_methodDataKlassObj                = NULL;
klassOop Universe::_klassKlassObj                     = NULL;
klassOop Universe::_arrayKlassKlassObj                = NULL;
klassOop Universe::_objArrayKlassKlassObj             = NULL;
klassOop Universe::_typeArrayKlassKlassObj            = NULL;
klassOop Universe::_instanceKlassKlassObj             = NULL;
klassOop Universe::_constantPoolKlassObj              = NULL;
klassOop Universe::_constantPoolCacheKlassObj         = NULL;
klassOop Universe::_compiledICHolderKlassObj          = NULL;
klassOop Universe::_systemObjArrayKlassObj            = NULL;
oop Universe::_int_mirror                             =  NULL;
oop Universe::_float_mirror                           =  NULL;
oop Universe::_double_mirror                          =  NULL;
oop Universe::_byte_mirror                            =  NULL;
oop Universe::_bool_mirror                            =  NULL;
oop Universe::_char_mirror                            =  NULL;
oop Universe::_long_mirror                            =  NULL;
oop Universe::_short_mirror                           =  NULL;
oop Universe::_void_mirror                            =  NULL;
oop Universe::_mirrors[T_VOID+1]                      =  { NULL /*, NULL...*/ };
oop Universe::_main_thread_group                      = NULL;
oop Universe::_system_thread_group                    = NULL;
typeArrayOop Universe::_the_empty_byte_array          = NULL;
typeArrayOop Universe::_the_empty_short_array         = NULL;
typeArrayOop Universe::_the_empty_int_array           = NULL;
objArrayOop Universe::_the_empty_system_obj_array     = NULL;
objArrayOop Universe::_the_empty_class_klass_array    = NULL;
objArrayOop Universe::_the_array_interfaces_array     = NULL;
LatestMethodOopCache* Universe::_finalizer_register_cache = NULL;
LatestMethodOopCache* Universe::_loader_addClass_cache    = NULL;
ActiveMethodOopsCache* Universe::_reflect_invoke_cache    = NULL;
oop Universe::_out_of_memory_error_java_heap          = NULL;
oop Universe::_out_of_memory_error_perm_gen           = NULL;
oop Universe::_out_of_memory_error_array_size         = NULL;
oop Universe::_out_of_memory_error_gc_overhead_limit  = NULL;
objArrayOop Universe::_preallocated_out_of_memory_error_array = NULL;
volatile jint Universe::_preallocated_out_of_memory_error_avail_count = 0;
bool Universe::_verify_in_progress                    = false;
oop Universe::_null_ptr_exception_instance            = NULL;
oop Universe::_arithmetic_exception_instance          = NULL;
oop Universe::_virtual_machine_error_instance         = NULL;
oop Universe::_vm_exception                           = NULL;
oop Universe::_emptySymbol                            = NULL;

// These variables are guarded by FullGCALot_lock.
debug_only(objArrayOop Universe::_fullgc_alot_dummy_array = NULL;)
debug_only(int Universe::_fullgc_alot_dummy_next      = 0;)


// Heap
int             Universe::_verify_count = 0;

int             Universe::_base_vtable_size = 0;
bool            Universe::_bootstrapping = false;
bool            Universe::_fully_initialized = false;

size_t          Universe::_heap_capacity_at_last_gc;
size_t          Universe::_heap_used_at_last_gc = 0;

CollectedHeap*  Universe::_collectedHeap = NULL;
address         Universe::_heap_base = NULL;


void Universe::basic_type_classes_do(void f(klassOop)) {
  f(boolArrayKlassObj());
  f(byteArrayKlassObj());
  f(charArrayKlassObj());
  f(intArrayKlassObj());
  f(shortArrayKlassObj());
  f(longArrayKlassObj());
  f(singleArrayKlassObj());
  f(doubleArrayKlassObj());
}


void Universe::system_classes_do(void f(klassOop)) {
  f(symbolKlassObj());
  f(methodKlassObj());
  f(constMethodKlassObj());
  f(methodDataKlassObj());
  f(klassKlassObj());
  f(arrayKlassKlassObj());
  f(objArrayKlassKlassObj());
  f(typeArrayKlassKlassObj());
  f(instanceKlassKlassObj());
  f(constantPoolKlassObj());
  f(systemObjArrayKlassObj());
}

void Universe::oops_do(OopClosure* f, bool do_all) {

  f->do_oop((oop*) &_int_mirror);
  f->do_oop((oop*) &_float_mirror);
  f->do_oop((oop*) &_double_mirror);
  f->do_oop((oop*) &_byte_mirror);
  f->do_oop((oop*) &_bool_mirror);
  f->do_oop((oop*) &_char_mirror);
  f->do_oop((oop*) &_long_mirror);
  f->do_oop((oop*) &_short_mirror);
  f->do_oop((oop*) &_void_mirror);

  // It's important to iterate over these guys even if they are null,
  // since that's how shared heaps are restored.
  for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
    f->do_oop((oop*) &_mirrors[i]);
  }
  assert(_mirrors[0] == NULL && _mirrors[T_BOOLEAN - 1] == NULL, "checking");

  // %%% Consider moving those "shared oops" over here with the others.
  f->do_oop((oop*)&_boolArrayKlassObj);
  f->do_oop((oop*)&_byteArrayKlassObj);
  f->do_oop((oop*)&_charArrayKlassObj);
  f->do_oop((oop*)&_intArrayKlassObj);
  f->do_oop((oop*)&_shortArrayKlassObj);
  f->do_oop((oop*)&_longArrayKlassObj);
  f->do_oop((oop*)&_singleArrayKlassObj);
  f->do_oop((oop*)&_doubleArrayKlassObj);
  f->do_oop((oop*)&_objectArrayKlassObj);
  {
    for (int i = 0; i < T_VOID+1; i++) {
      if (_typeArrayKlassObjs[i] != NULL) {
        assert(i >= T_BOOLEAN, "checking");
        f->do_oop((oop*)&_typeArrayKlassObjs[i]);
      } else if (do_all) {
        f->do_oop((oop*)&_typeArrayKlassObjs[i]);
      }
    }
  }
  f->do_oop((oop*)&_symbolKlassObj);
  f->do_oop((oop*)&_methodKlassObj);
  f->do_oop((oop*)&_constMethodKlassObj);
  f->do_oop((oop*)&_methodDataKlassObj);
  f->do_oop((oop*)&_klassKlassObj);
  f->do_oop((oop*)&_arrayKlassKlassObj);
  f->do_oop((oop*)&_objArrayKlassKlassObj);
  f->do_oop((oop*)&_typeArrayKlassKlassObj);
  f->do_oop((oop*)&_instanceKlassKlassObj);
  f->do_oop((oop*)&_constantPoolKlassObj);
  f->do_oop((oop*)&_constantPoolCacheKlassObj);
  f->do_oop((oop*)&_compiledICHolderKlassObj);
  f->do_oop((oop*)&_systemObjArrayKlassObj);
  f->do_oop((oop*)&_the_empty_byte_array);
  f->do_oop((oop*)&_the_empty_short_array);
  f->do_oop((oop*)&_the_empty_int_array);
  f->do_oop((oop*)&_the_empty_system_obj_array);
  f->do_oop((oop*)&_the_empty_class_klass_array);
  f->do_oop((oop*)&_the_array_interfaces_array);
  _finalizer_register_cache->oops_do(f);
  _loader_addClass_cache->oops_do(f);
  _reflect_invoke_cache->oops_do(f);
  f->do_oop((oop*)&_out_of_memory_error_java_heap);
  f->do_oop((oop*)&_out_of_memory_error_perm_gen);
  f->do_oop((oop*)&_out_of_memory_error_array_size);
  f->do_oop((oop*)&_out_of_memory_error_gc_overhead_limit);
  if (_preallocated_out_of_memory_error_array != (oop)NULL) {   // NULL when DumpSharedSpaces
    f->do_oop((oop*)&_preallocated_out_of_memory_error_array);
  }
  f->do_oop((oop*)&_null_ptr_exception_instance);
  f->do_oop((oop*)&_arithmetic_exception_instance);
  f->do_oop((oop*)&_virtual_machine_error_instance);
  f->do_oop((oop*)&_main_thread_group);
  f->do_oop((oop*)&_system_thread_group);
  f->do_oop((oop*)&_vm_exception);
  f->do_oop((oop*)&_emptySymbol);
  debug_only(f->do_oop((oop*)&_fullgc_alot_dummy_array);)
}


void Universe::check_alignment(uintx size, uintx alignment, const char* name) {
  if (size < alignment || size % alignment != 0) {
    ResourceMark rm;
    stringStream st;
    st.print("Size of %s (%ld bytes) must be aligned to %ld bytes", name, size, alignment);
    char* error = st.as_string();
    vm_exit_during_initialization(error);
  }
}


void Universe::genesis(TRAPS) {
  ResourceMark rm;
  { FlagSetting fs(_bootstrapping, true);

    { MutexLocker mc(Compile_lock);

      // determine base vtable size; without that we cannot create the array klasses
      compute_base_vtable_size();

      if (!UseSharedSpaces) {
        _klassKlassObj          = klassKlass::create_klass(CHECK);
        _arrayKlassKlassObj     = arrayKlassKlass::create_klass(CHECK);

        _objArrayKlassKlassObj  = objArrayKlassKlass::create_klass(CHECK);
        _instanceKlassKlassObj  = instanceKlassKlass::create_klass(CHECK);
        _typeArrayKlassKlassObj = typeArrayKlassKlass::create_klass(CHECK);

        _symbolKlassObj         = symbolKlass::create_klass(CHECK);

        _emptySymbol            = oopFactory::new_symbol("", CHECK);

        _boolArrayKlassObj      = typeArrayKlass::create_klass(T_BOOLEAN, sizeof(jboolean), CHECK);
        _charArrayKlassObj      = typeArrayKlass::create_klass(T_CHAR,    sizeof(jchar),    CHECK);
        _singleArrayKlassObj    = typeArrayKlass::create_klass(T_FLOAT,   sizeof(jfloat),   CHECK);
        _doubleArrayKlassObj    = typeArrayKlass::create_klass(T_DOUBLE,  sizeof(jdouble),  CHECK);
        _byteArrayKlassObj      = typeArrayKlass::create_klass(T_BYTE,    sizeof(jbyte),    CHECK);
        _shortArrayKlassObj     = typeArrayKlass::create_klass(T_SHORT,   sizeof(jshort),   CHECK);
        _intArrayKlassObj       = typeArrayKlass::create_klass(T_INT,     sizeof(jint),     CHECK);
        _longArrayKlassObj      = typeArrayKlass::create_klass(T_LONG,    sizeof(jlong),    CHECK);

        _typeArrayKlassObjs[T_BOOLEAN] = _boolArrayKlassObj;
        _typeArrayKlassObjs[T_CHAR]    = _charArrayKlassObj;
        _typeArrayKlassObjs[T_FLOAT]   = _singleArrayKlassObj;
        _typeArrayKlassObjs[T_DOUBLE]  = _doubleArrayKlassObj;
        _typeArrayKlassObjs[T_BYTE]    = _byteArrayKlassObj;
        _typeArrayKlassObjs[T_SHORT]   = _shortArrayKlassObj;
        _typeArrayKlassObjs[T_INT]     = _intArrayKlassObj;
        _typeArrayKlassObjs[T_LONG]    = _longArrayKlassObj;

        _methodKlassObj         = methodKlass::create_klass(CHECK);
        _constMethodKlassObj    = constMethodKlass::create_klass(CHECK);
        _methodDataKlassObj     = methodDataKlass::create_klass(CHECK);
        _constantPoolKlassObj       = constantPoolKlass::create_klass(CHECK);
        _constantPoolCacheKlassObj  = constantPoolCacheKlass::create_klass(CHECK);

        _compiledICHolderKlassObj   = compiledICHolderKlass::create_klass(CHECK);
        _systemObjArrayKlassObj     = objArrayKlassKlass::cast(objArrayKlassKlassObj())->allocate_system_objArray_klass(CHECK);

        _the_empty_byte_array      = oopFactory::new_permanent_byteArray(0, CHECK);
        _the_empty_short_array      = oopFactory::new_permanent_shortArray(0, CHECK);
        _the_empty_int_array        = oopFactory::new_permanent_intArray(0, CHECK);
        _the_empty_system_obj_array = oopFactory::new_system_objArray(0, CHECK);

        _the_array_interfaces_array = oopFactory::new_system_objArray(2, CHECK);
        _vm_exception               = oopFactory::new_symbol("vm exception holder", CHECK);
      } else {

        FileMapInfo *mapinfo = FileMapInfo::current_info();
        char* buffer = mapinfo->region_base(CompactingPermGenGen::md);
        void** vtbl_list = (void**)buffer;
        init_self_patching_vtbl_list(vtbl_list,
                                     CompactingPermGenGen::vtbl_list_size);
      }
    }

    vmSymbols::initialize(CHECK);

    SystemDictionary::initialize(CHECK);

    klassOop ok = SystemDictionary::object_klass();

    if (UseSharedSpaces) {
      // Verify shared interfaces array.
      assert(_the_array_interfaces_array->obj_at(0) ==
             SystemDictionary::cloneable_klass(), "u3");
      assert(_the_array_interfaces_array->obj_at(1) ==
             SystemDictionary::serializable_klass(), "u3");

      // Verify element klass for system obj array klass
      assert(objArrayKlass::cast(_systemObjArrayKlassObj)->element_klass() == ok, "u1");
      assert(objArrayKlass::cast(_systemObjArrayKlassObj)->bottom_klass() == ok, "u2");

      // Verify super class for the classes created above
      assert(Klass::cast(boolArrayKlassObj()     )->super() == ok, "u3");
      assert(Klass::cast(charArrayKlassObj()     )->super() == ok, "u3");
      assert(Klass::cast(singleArrayKlassObj()   )->super() == ok, "u3");
      assert(Klass::cast(doubleArrayKlassObj()   )->super() == ok, "u3");
      assert(Klass::cast(byteArrayKlassObj()     )->super() == ok, "u3");
      assert(Klass::cast(shortArrayKlassObj()    )->super() == ok, "u3");
      assert(Klass::cast(intArrayKlassObj()      )->super() == ok, "u3");
      assert(Klass::cast(longArrayKlassObj()     )->super() == ok, "u3");
      assert(Klass::cast(constantPoolKlassObj()  )->super() == ok, "u3");
      assert(Klass::cast(systemObjArrayKlassObj())->super() == ok, "u3");
    } else {
      // Set up shared interfaces array.  (Do this before supers are set up.)
      _the_array_interfaces_array->obj_at_put(0, SystemDictionary::cloneable_klass());
      _the_array_interfaces_array->obj_at_put(1, SystemDictionary::serializable_klass());

      // Set element klass for system obj array klass
      objArrayKlass::cast(_systemObjArrayKlassObj)->set_element_klass(ok);
      objArrayKlass::cast(_systemObjArrayKlassObj)->set_bottom_klass(ok);

      // Set super class for the classes created above
      Klass::cast(boolArrayKlassObj()     )->initialize_supers(ok, CHECK);
      Klass::cast(charArrayKlassObj()     )->initialize_supers(ok, CHECK);
      Klass::cast(singleArrayKlassObj()   )->initialize_supers(ok, CHECK);
      Klass::cast(doubleArrayKlassObj()   )->initialize_supers(ok, CHECK);
      Klass::cast(byteArrayKlassObj()     )->initialize_supers(ok, CHECK);
      Klass::cast(shortArrayKlassObj()    )->initialize_supers(ok, CHECK);
      Klass::cast(intArrayKlassObj()      )->initialize_supers(ok, CHECK);
      Klass::cast(longArrayKlassObj()     )->initialize_supers(ok, CHECK);
      Klass::cast(constantPoolKlassObj()  )->initialize_supers(ok, CHECK);
      Klass::cast(systemObjArrayKlassObj())->initialize_supers(ok, CHECK);
      Klass::cast(boolArrayKlassObj()     )->set_super(ok);
      Klass::cast(charArrayKlassObj()     )->set_super(ok);
      Klass::cast(singleArrayKlassObj()   )->set_super(ok);
      Klass::cast(doubleArrayKlassObj()   )->set_super(ok);
      Klass::cast(byteArrayKlassObj()     )->set_super(ok);
      Klass::cast(shortArrayKlassObj()    )->set_super(ok);
      Klass::cast(intArrayKlassObj()      )->set_super(ok);
      Klass::cast(longArrayKlassObj()     )->set_super(ok);
      Klass::cast(constantPoolKlassObj()  )->set_super(ok);
      Klass::cast(systemObjArrayKlassObj())->set_super(ok);
    }

    Klass::cast(boolArrayKlassObj()     )->append_to_sibling_list();
    Klass::cast(charArrayKlassObj()     )->append_to_sibling_list();
    Klass::cast(singleArrayKlassObj()   )->append_to_sibling_list();
    Klass::cast(doubleArrayKlassObj()   )->append_to_sibling_list();
    Klass::cast(byteArrayKlassObj()     )->append_to_sibling_list();
    Klass::cast(shortArrayKlassObj()    )->append_to_sibling_list();
    Klass::cast(intArrayKlassObj()      )->append_to_sibling_list();
    Klass::cast(longArrayKlassObj()     )->append_to_sibling_list();
    Klass::cast(constantPoolKlassObj()  )->append_to_sibling_list();
    Klass::cast(systemObjArrayKlassObj())->append_to_sibling_list();
  } // end of core bootstrapping

  // Initialize _objectArrayKlass after core bootstraping to make
  // sure the super class is set up properly for _objectArrayKlass.
  _objectArrayKlassObj = instanceKlass::
    cast(SystemDictionary::object_klass())->array_klass(1, CHECK);
  // Add the class to the class hierarchy manually to make sure that
  // its vtable is initialized after core bootstrapping is completed.
  Klass::cast(_objectArrayKlassObj)->append_to_sibling_list();

  // Compute is_jdk version flags.
  // Only 1.3 or later has the java.lang.Shutdown class.
  // Only 1.4 or later has the java.lang.CharSequence interface.
  // Only 1.5 or later has the java.lang.management.MemoryUsage class.
  if (JDK_Version::is_partially_initialized()) {
    uint8_t jdk_version;
    klassOop k = SystemDictionary::resolve_or_null(
        vmSymbolHandles::java_lang_management_MemoryUsage(), THREAD);
    CLEAR_PENDING_EXCEPTION; // ignore exceptions
    if (k == NULL) {
      k = SystemDictionary::resolve_or_null(
          vmSymbolHandles::java_lang_CharSequence(), THREAD);
      CLEAR_PENDING_EXCEPTION; // ignore exceptions
      if (k == NULL) {
        k = SystemDictionary::resolve_or_null(
            vmSymbolHandles::java_lang_Shutdown(), THREAD);
        CLEAR_PENDING_EXCEPTION; // ignore exceptions
        if (k == NULL) {
          jdk_version = 2;
        } else {
          jdk_version = 3;
        }
      } else {
        jdk_version = 4;
      }
    } else {
      jdk_version = 5;
    }
    JDK_Version::fully_initialize(jdk_version);
  }

  #ifdef ASSERT
  if (FullGCALot) {
    // Allocate an array of dummy objects.
    // We'd like these to be at the bottom of the old generation,
    // so that when we free one and then collect,
    // (almost) the whole heap moves
    // and we find out if we actually update all the oops correctly.
    // But we can't allocate directly in the old generation,
    // so we allocate wherever, and hope that the first collection
    // moves these objects to the bottom of the old generation.
    // We can allocate directly in the permanent generation, so we do.
    int size;
    if (UseConcMarkSweepGC) {
      warning("Using +FullGCALot with concurrent mark sweep gc "
              "will not force all objects to relocate");
      size = FullGCALotDummies;
    } else {
      size = FullGCALotDummies * 2;
    }
    objArrayOop    naked_array = oopFactory::new_system_objArray(size, CHECK);
    objArrayHandle dummy_array(THREAD, naked_array);
    int i = 0;
    while (i < size) {
      if (!UseConcMarkSweepGC) {
        // Allocate dummy in old generation
        oop dummy = instanceKlass::cast(SystemDictionary::object_klass())->allocate_instance(CHECK);
        dummy_array->obj_at_put(i++, dummy);
      }
      // Allocate dummy in permanent generation
      oop dummy = instanceKlass::cast(SystemDictionary::object_klass())->allocate_permanent_instance(CHECK);
      dummy_array->obj_at_put(i++, dummy);
    }
    {
      // Only modify the global variable inside the mutex.
      // If we had a race to here, the other dummy_array instances
      // and their elements just get dropped on the floor, which is fine.
      MutexLocker ml(FullGCALot_lock);
      if (_fullgc_alot_dummy_array == NULL) {
        _fullgc_alot_dummy_array = dummy_array();
      }
    }
    assert(i == _fullgc_alot_dummy_array->length(), "just checking");
  }
  #endif
}


static inline void add_vtable(void** list, int* n, Klass* o, int count) {
  list[(*n)++] = *(void**)&o->vtbl_value();
  guarantee((*n) <= count, "vtable list too small.");
}


void Universe::init_self_patching_vtbl_list(void** list, int count) {
  int n = 0;
  { klassKlass o;             add_vtable(list, &n, &o, count); }
  { arrayKlassKlass o;        add_vtable(list, &n, &o, count); }
  { objArrayKlassKlass o;     add_vtable(list, &n, &o, count); }
  { instanceKlassKlass o;     add_vtable(list, &n, &o, count); }
  { instanceKlass o;          add_vtable(list, &n, &o, count); }
  { instanceRefKlass o;       add_vtable(list, &n, &o, count); }
  { typeArrayKlassKlass o;    add_vtable(list, &n, &o, count); }
  { symbolKlass o;            add_vtable(list, &n, &o, count); }
  { typeArrayKlass o;         add_vtable(list, &n, &o, count); }
  { methodKlass o;            add_vtable(list, &n, &o, count); }
  { constMethodKlass o;       add_vtable(list, &n, &o, count); }
  { constantPoolKlass o;      add_vtable(list, &n, &o, count); }
  { constantPoolCacheKlass o; add_vtable(list, &n, &o, count); }
  { objArrayKlass o;          add_vtable(list, &n, &o, count); }
  { methodDataKlass o;        add_vtable(list, &n, &o, count); }
  { compiledICHolderKlass o;  add_vtable(list, &n, &o, count); }
}


class FixupMirrorClosure: public ObjectClosure {
 public:
  virtual void do_object(oop obj) {
    if (obj->is_klass()) {
      EXCEPTION_MARK;
      KlassHandle k(THREAD, klassOop(obj));
      // We will never reach the CATCH below since Exceptions::_throw will cause
      // the VM to exit if an exception is thrown during initialization
      java_lang_Class::create_mirror(k, CATCH);
      // This call unconditionally creates a new mirror for k,
      // and links in k's component_mirror field if k is an array.
      // If k is an objArray, k's element type must already have
      // a mirror.  In other words, this closure must process
      // the component type of an objArray k before it processes k.
      // This works because the permgen iterator presents arrays
      // and their component types in order of creation.
    }
  }
};

void Universe::initialize_basic_type_mirrors(TRAPS) {
  if (UseSharedSpaces) {
    assert(_int_mirror != NULL, "already loaded");
    assert(_void_mirror == _mirrors[T_VOID], "consistently loaded");
  } else {

    assert(_int_mirror==NULL, "basic type mirrors already initialized");
    _int_mirror     =
      java_lang_Class::create_basic_type_mirror("int",    T_INT, CHECK);
    _float_mirror   =
      java_lang_Class::create_basic_type_mirror("float",  T_FLOAT,   CHECK);
    _double_mirror  =
      java_lang_Class::create_basic_type_mirror("double", T_DOUBLE,  CHECK);
    _byte_mirror    =
      java_lang_Class::create_basic_type_mirror("byte",   T_BYTE, CHECK);
    _bool_mirror    =
      java_lang_Class::create_basic_type_mirror("boolean",T_BOOLEAN, CHECK);
    _char_mirror    =
      java_lang_Class::create_basic_type_mirror("char",   T_CHAR, CHECK);
    _long_mirror    =
      java_lang_Class::create_basic_type_mirror("long",   T_LONG, CHECK);
    _short_mirror   =
      java_lang_Class::create_basic_type_mirror("short",  T_SHORT,   CHECK);
    _void_mirror    =
      java_lang_Class::create_basic_type_mirror("void",   T_VOID, CHECK);

    _mirrors[T_INT]     = _int_mirror;
    _mirrors[T_FLOAT]   = _float_mirror;
    _mirrors[T_DOUBLE]  = _double_mirror;
    _mirrors[T_BYTE]    = _byte_mirror;
    _mirrors[T_BOOLEAN] = _bool_mirror;
    _mirrors[T_CHAR]    = _char_mirror;
    _mirrors[T_LONG]    = _long_mirror;
    _mirrors[T_SHORT]   = _short_mirror;
    _mirrors[T_VOID]    = _void_mirror;
    //_mirrors[T_OBJECT]  = instanceKlass::cast(_object_klass)->java_mirror();
    //_mirrors[T_ARRAY]   = instanceKlass::cast(_object_klass)->java_mirror();
  }
}

void Universe::fixup_mirrors(TRAPS) {
  // Bootstrap problem: all classes gets a mirror (java.lang.Class instance) assigned eagerly,
  // but we cannot do that for classes created before java.lang.Class is loaded. Here we simply
  // walk over permanent objects created so far (mostly classes) and fixup their mirrors. Note
  // that the number of objects allocated at this point is very small.
  assert(SystemDictionary::class_klass_loaded(), "java.lang.Class should be loaded");
  FixupMirrorClosure blk;
  Universe::heap()->permanent_object_iterate(&blk);
}


static bool has_run_finalizers_on_exit = false;

void Universe::run_finalizers_on_exit() {
  if (has_run_finalizers_on_exit) return;
  has_run_finalizers_on_exit = true;

  // Called on VM exit. This ought to be run in a separate thread.
  if (TraceReferenceGC) tty->print_cr("Callback to run finalizers on exit");
  {
    PRESERVE_EXCEPTION_MARK;
    KlassHandle finalizer_klass(THREAD, SystemDictionary::finalizer_klass());
    JavaValue result(T_VOID);
    JavaCalls::call_static(
      &result,
      finalizer_klass,
      vmSymbolHandles::run_finalizers_on_exit_name(),
      vmSymbolHandles::void_method_signature(),
      THREAD
    );
    // Ignore any pending exceptions
    CLEAR_PENDING_EXCEPTION;
  }
}


// initialize_vtable could cause gc if
// 1) we specified true to initialize_vtable and
// 2) this ran after gc was enabled
// In case those ever change we use handles for oops
void Universe::reinitialize_vtable_of(KlassHandle k_h, TRAPS) {
  // init vtable of k and all subclasses
  Klass* ko = k_h()->klass_part();
  klassVtable* vt = ko->vtable();
  if (vt) vt->initialize_vtable(false, CHECK);
  if (ko->oop_is_instance()) {
    instanceKlass* ik = (instanceKlass*)ko;
    for (KlassHandle s_h(THREAD, ik->subklass()); s_h() != NULL; s_h = (THREAD, s_h()->klass_part()->next_sibling())) {
      reinitialize_vtable_of(s_h, CHECK);
    }
  }
}


void initialize_itable_for_klass(klassOop k, TRAPS) {
  instanceKlass::cast(k)->itable()->initialize_itable(false, CHECK);
}


void Universe::reinitialize_itables(TRAPS) {
  SystemDictionary::classes_do(initialize_itable_for_klass, CHECK);

}


bool Universe::on_page_boundary(void* addr) {
  return ((uintptr_t) addr) % os::vm_page_size() == 0;
}


bool Universe::should_fill_in_stack_trace(Handle throwable) {
  // never attempt to fill in the stack trace of preallocated errors that do not have
  // backtrace. These errors are kept alive forever and may be "re-used" when all
  // preallocated errors with backtrace have been consumed. Also need to avoid
  // a potential loop which could happen if an out of memory occurs when attempting
  // to allocate the backtrace.
  return ((throwable() != Universe::_out_of_memory_error_java_heap) &&
          (throwable() != Universe::_out_of_memory_error_perm_gen)  &&
          (throwable() != Universe::_out_of_memory_error_array_size) &&
          (throwable() != Universe::_out_of_memory_error_gc_overhead_limit));
}


oop Universe::gen_out_of_memory_error(oop default_err) {
  // generate an out of memory error:
  // - if there is a preallocated error with backtrace available then return it wth
  //   a filled in stack trace.
  // - if there are no preallocated errors with backtrace available then return
  //   an error without backtrace.
  int next;
  if (_preallocated_out_of_memory_error_avail_count > 0) {
    next = (int)Atomic::add(-1, &_preallocated_out_of_memory_error_avail_count);
    assert(next < (int)PreallocatedOutOfMemoryErrorCount, "avail count is corrupt");
  } else {
    next = -1;
  }
  if (next < 0) {
    // all preallocated errors have been used.
    // return default
    return default_err;
  } else {
    // get the error object at the slot and set set it to NULL so that the
    // array isn't keeping it alive anymore.
    oop exc = preallocated_out_of_memory_errors()->obj_at(next);
    assert(exc != NULL, "slot has been used already");
    preallocated_out_of_memory_errors()->obj_at_put(next, NULL);

    // use the message from the default error
    oop msg = java_lang_Throwable::message(default_err);
    assert(msg != NULL, "no message");
    java_lang_Throwable::set_message(exc, msg);

    // populate the stack trace and return it.
    java_lang_Throwable::fill_in_stack_trace_of_preallocated_backtrace(exc);
    return exc;
  }
}

static intptr_t non_oop_bits = 0;

void* Universe::non_oop_word() {
  // Neither the high bits nor the low bits of this value is allowed
  // to look like (respectively) the high or low bits of a real oop.
  //
  // High and low are CPU-specific notions, but low always includes
  // the low-order bit.  Since oops are always aligned at least mod 4,
  // setting the low-order bit will ensure that the low half of the
  // word will never look like that of a real oop.
  //
  // Using the OS-supplied non-memory-address word (usually 0 or -1)
  // will take care of the high bits, however many there are.

  if (non_oop_bits == 0) {
    non_oop_bits = (intptr_t)os::non_memory_address_word() | 1;
  }

  return (void*)non_oop_bits;
}

jint universe_init() {
  assert(!Universe::_fully_initialized, "called after initialize_vtables");
  guarantee(1 << LogHeapWordSize == sizeof(HeapWord),
         "LogHeapWordSize is incorrect.");
  guarantee(sizeof(oop) >= sizeof(HeapWord), "HeapWord larger than oop?");
  guarantee(sizeof(oop) % sizeof(HeapWord) == 0,
            "oop size is not not a multiple of HeapWord size");
  TraceTime timer("Genesis", TraceStartupTime);
  GC_locker::lock();  // do not allow gc during bootstrapping
  JavaClasses::compute_hard_coded_offsets();

  // Get map info from shared archive file.
  if (DumpSharedSpaces)
    UseSharedSpaces = false;

  FileMapInfo* mapinfo = NULL;
  if (UseSharedSpaces) {
    mapinfo = NEW_C_HEAP_OBJ(FileMapInfo);
    memset(mapinfo, 0, sizeof(FileMapInfo));

    // Open the shared archive file, read and validate the header. If
    // initialization files, shared spaces [UseSharedSpaces] are
    // disabled and the file is closed.

    if (mapinfo->initialize()) {
      FileMapInfo::set_current_info(mapinfo);
    } else {
      assert(!mapinfo->is_open() && !UseSharedSpaces,
             "archive file not closed or shared spaces not disabled.");
    }
  }

  jint status = Universe::initialize_heap();
  if (status != JNI_OK) {
    return status;
  }

  // We have a heap so create the methodOop caches before
  // CompactingPermGenGen::initialize_oops() tries to populate them.
  Universe::_finalizer_register_cache = new LatestMethodOopCache();
  Universe::_loader_addClass_cache    = new LatestMethodOopCache();
  Universe::_reflect_invoke_cache     = new ActiveMethodOopsCache();

  if (UseSharedSpaces) {

    // Read the data structures supporting the shared spaces (shared
    // system dictionary, symbol table, etc.).  After that, access to
    // the file (other than the mapped regions) is no longer needed, and
    // the file is closed. Closing the file does not affect the
    // currently mapped regions.

    CompactingPermGenGen::initialize_oops();
    mapinfo->close();

  } else {
    SymbolTable::create_table();
    StringTable::create_table();
    ClassLoader::create_package_info_table();
  }

  return JNI_OK;
}

jint Universe::initialize_heap() {

  if (UseParallelGC) {
#ifndef SERIALGC
    Universe::_collectedHeap = new ParallelScavengeHeap();
#else  // SERIALGC
    fatal("UseParallelGC not supported in java kernel vm.");
#endif // SERIALGC

  } else if (UseG1GC) {
#ifndef SERIALGC
    G1CollectorPolicy* g1p = new G1CollectorPolicy_BestRegionsFirst();
    G1CollectedHeap* g1h = new G1CollectedHeap(g1p);
    Universe::_collectedHeap = g1h;
#else  // SERIALGC
    fatal("UseG1GC not supported in java kernel vm.");
#endif // SERIALGC

  } else {
    GenCollectorPolicy *gc_policy;

    if (UseSerialGC) {
      gc_policy = new MarkSweepPolicy();
    } else if (UseConcMarkSweepGC) {
#ifndef SERIALGC
      if (UseAdaptiveSizePolicy) {
        gc_policy = new ASConcurrentMarkSweepPolicy();
      } else {
        gc_policy = new ConcurrentMarkSweepPolicy();
      }
#else   // SERIALGC
    fatal("UseConcMarkSweepGC not supported in java kernel vm.");
#endif // SERIALGC
    } else { // default old generation
      gc_policy = new MarkSweepPolicy();
    }

    Universe::_collectedHeap = new GenCollectedHeap(gc_policy);
  }

  jint status = Universe::heap()->initialize();
  if (status != JNI_OK) {
    return status;
  }
  if (UseCompressedOops) {
    // Subtract a page because something can get allocated at heap base.
    // This also makes implicit null checking work, because the
    // memory+1 page below heap_base needs to cause a signal.
    // See needs_explicit_null_check.
    // Only set the heap base for compressed oops because it indicates
    // compressed oops for pstack code.
    Universe::_heap_base = Universe::heap()->base() - os::vm_page_size();
  }

  // We will never reach the CATCH below since Exceptions::_throw will cause
  // the VM to exit if an exception is thrown during initialization

  if (UseTLAB) {
    assert(Universe::heap()->supports_tlab_allocation(),
           "Should support thread-local allocation buffers");
    ThreadLocalAllocBuffer::startup_initialization();
  }
  return JNI_OK;
}

// It's the caller's repsonsibility to ensure glitch-freedom
// (if required).
void Universe::update_heap_info_at_gc() {
  _heap_capacity_at_last_gc = heap()->capacity();
  _heap_used_at_last_gc     = heap()->used();
}



void universe2_init() {
  EXCEPTION_MARK;
  Universe::genesis(CATCH);
  // Although we'd like to verify here that the state of the heap
  // is good, we can't because the main thread has not yet added
  // itself to the threads list (so, using current interfaces
  // we can't "fill" its TLAB), unless TLABs are disabled.
  if (VerifyBeforeGC && !UseTLAB &&
      Universe::heap()->total_collections() >= VerifyGCStartAt) {
     Universe::heap()->prepare_for_verify();
     Universe::verify();   // make sure we're starting with a clean slate
  }
}


// This function is defined in JVM.cpp
extern void initialize_converter_functions();

bool universe_post_init() {
  Universe::_fully_initialized = true;
  EXCEPTION_MARK;
  { ResourceMark rm;
    Interpreter::initialize();      // needed for interpreter entry points
    if (!UseSharedSpaces) {
      KlassHandle ok_h(THREAD, SystemDictionary::object_klass());
      Universe::reinitialize_vtable_of(ok_h, CHECK_false);
      Universe::reinitialize_itables(CHECK_false);
    }
  }

  klassOop k;
  instanceKlassHandle k_h;
  if (!UseSharedSpaces) {
    // Setup preallocated empty java.lang.Class array
    Universe::_the_empty_class_klass_array = oopFactory::new_objArray(SystemDictionary::class_klass(), 0, CHECK_false);
    // Setup preallocated OutOfMemoryError errors
    k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_OutOfMemoryError(), true, CHECK_false);
    k_h = instanceKlassHandle(THREAD, k);
    Universe::_out_of_memory_error_java_heap = k_h->allocate_permanent_instance(CHECK_false);
    Universe::_out_of_memory_error_perm_gen = k_h->allocate_permanent_instance(CHECK_false);
    Universe::_out_of_memory_error_array_size = k_h->allocate_permanent_instance(CHECK_false);
    Universe::_out_of_memory_error_gc_overhead_limit =
      k_h->allocate_permanent_instance(CHECK_false);

    // Setup preallocated NullPointerException
    // (this is currently used for a cheap & dirty solution in compiler exception handling)
    k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_NullPointerException(), true, CHECK_false);
    Universe::_null_ptr_exception_instance = instanceKlass::cast(k)->allocate_permanent_instance(CHECK_false);
    // Setup preallocated ArithmeticException
    // (this is currently used for a cheap & dirty solution in compiler exception handling)
    k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_ArithmeticException(), true, CHECK_false);
    Universe::_arithmetic_exception_instance = instanceKlass::cast(k)->allocate_permanent_instance(CHECK_false);
    // Virtual Machine Error for when we get into a situation we can't resolve
    k = SystemDictionary::resolve_or_fail(
      vmSymbolHandles::java_lang_VirtualMachineError(), true, CHECK_false);
    bool linked = instanceKlass::cast(k)->link_class_or_fail(CHECK_false);
    if (!linked) {
      tty->print_cr("Unable to link/verify VirtualMachineError class");
      return false; // initialization failed
    }
    Universe::_virtual_machine_error_instance =
      instanceKlass::cast(k)->allocate_permanent_instance(CHECK_false);
  }
  if (!DumpSharedSpaces) {
    // These are the only Java fields that are currently set during shared space dumping.
    // We prefer to not handle this generally, so we always reinitialize these detail messages.
    Handle msg = java_lang_String::create_from_str("Java heap space", CHECK_false);
    java_lang_Throwable::set_message(Universe::_out_of_memory_error_java_heap, msg());

    msg = java_lang_String::create_from_str("PermGen space", CHECK_false);
    java_lang_Throwable::set_message(Universe::_out_of_memory_error_perm_gen, msg());

    msg = java_lang_String::create_from_str("Requested array size exceeds VM limit", CHECK_false);
    java_lang_Throwable::set_message(Universe::_out_of_memory_error_array_size, msg());

    msg = java_lang_String::create_from_str("GC overhead limit exceeded", CHECK_false);
    java_lang_Throwable::set_message(Universe::_out_of_memory_error_gc_overhead_limit, msg());

    msg = java_lang_String::create_from_str("/ by zero", CHECK_false);
    java_lang_Throwable::set_message(Universe::_arithmetic_exception_instance, msg());

    // Setup the array of errors that have preallocated backtrace
    k = Universe::_out_of_memory_error_java_heap->klass();
    assert(k->klass_part()->name() == vmSymbols::java_lang_OutOfMemoryError(), "should be out of memory error");
    k_h = instanceKlassHandle(THREAD, k);

    int len = (StackTraceInThrowable) ? (int)PreallocatedOutOfMemoryErrorCount : 0;
    Universe::_preallocated_out_of_memory_error_array = oopFactory::new_objArray(k_h(), len, CHECK_false);
    for (int i=0; i<len; i++) {
      oop err = k_h->allocate_permanent_instance(CHECK_false);
      Handle err_h = Handle(THREAD, err);
      java_lang_Throwable::allocate_backtrace(err_h, CHECK_false);
      Universe::preallocated_out_of_memory_errors()->obj_at_put(i, err_h());
    }
    Universe::_preallocated_out_of_memory_error_avail_count = (jint)len;
  }


  // Setup static method for registering finalizers
  // The finalizer klass must be linked before looking up the method, in
  // case it needs to get rewritten.
  instanceKlass::cast(SystemDictionary::finalizer_klass())->link_class(CHECK_false);
  methodOop m = instanceKlass::cast(SystemDictionary::finalizer_klass())->find_method(
                                  vmSymbols::register_method_name(),
                                  vmSymbols::register_method_signature());
  if (m == NULL || !m->is_static()) {
    THROW_MSG_(vmSymbols::java_lang_NoSuchMethodException(),
      "java.lang.ref.Finalizer.register", false);
  }
  Universe::_finalizer_register_cache->init(
    SystemDictionary::finalizer_klass(), m, CHECK_false);

  // Resolve on first use and initialize class.
  // Note: No race-condition here, since a resolve will always return the same result

  // Setup method for security checks
  k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_reflect_Method(), true, CHECK_false);
  k_h = instanceKlassHandle(THREAD, k);
  k_h->link_class(CHECK_false);
  m = k_h->find_method(vmSymbols::invoke_name(), vmSymbols::object_array_object_object_signature());
  if (m == NULL || m->is_static()) {
    THROW_MSG_(vmSymbols::java_lang_NoSuchMethodException(),
      "java.lang.reflect.Method.invoke", false);
  }
  Universe::_reflect_invoke_cache->init(k_h(), m, CHECK_false);

  // Setup method for registering loaded classes in class loader vector
  instanceKlass::cast(SystemDictionary::classloader_klass())->link_class(CHECK_false);
  m = instanceKlass::cast(SystemDictionary::classloader_klass())->find_method(vmSymbols::addClass_name(), vmSymbols::class_void_signature());
  if (m == NULL || m->is_static()) {
    THROW_MSG_(vmSymbols::java_lang_NoSuchMethodException(),
      "java.lang.ClassLoader.addClass", false);
  }
  Universe::_loader_addClass_cache->init(
    SystemDictionary::classloader_klass(), m, CHECK_false);

  // The folowing is initializing converter functions for serialization in
  // JVM.cpp. If we clean up the StrictMath code above we may want to find
  // a better solution for this as well.
  initialize_converter_functions();

  // This needs to be done before the first scavenge/gc, since
  // it's an input to soft ref clearing policy.
  {
    MutexLocker x(Heap_lock);
    Universe::update_heap_info_at_gc();
  }

  // ("weak") refs processing infrastructure initialization
  Universe::heap()->post_initialize();

  GC_locker::unlock();  // allow gc after bootstrapping

  MemoryService::set_universe_heap(Universe::_collectedHeap);
  return true;
}


void Universe::compute_base_vtable_size() {
  _base_vtable_size = ClassLoader::compute_Object_vtable();
}


// %%% The Universe::flush_foo methods belong in CodeCache.

// Flushes compiled methods dependent on dependee.
void Universe::flush_dependents_on(instanceKlassHandle dependee) {
  assert_lock_strong(Compile_lock);

  if (CodeCache::number_of_nmethods_with_dependencies() == 0) return;

  // CodeCache can only be updated by a thread_in_VM and they will all be
  // stopped dring the safepoint so CodeCache will be safe to update without
  // holding the CodeCache_lock.

  DepChange changes(dependee);

  // Compute the dependent nmethods
  if (CodeCache::mark_for_deoptimization(changes) > 0) {
    // At least one nmethod has been marked for deoptimization
    VM_Deoptimize op;
    VMThread::execute(&op);
  }
}

#ifdef HOTSWAP
// Flushes compiled methods dependent on dependee in the evolutionary sense
void Universe::flush_evol_dependents_on(instanceKlassHandle ev_k_h) {
  // --- Compile_lock is not held. However we are at a safepoint.
  assert_locked_or_safepoint(Compile_lock);
  if (CodeCache::number_of_nmethods_with_dependencies() == 0) return;

  // CodeCache can only be updated by a thread_in_VM and they will all be
  // stopped dring the safepoint so CodeCache will be safe to update without
  // holding the CodeCache_lock.

  // Compute the dependent nmethods
  if (CodeCache::mark_for_evol_deoptimization(ev_k_h) > 0) {
    // At least one nmethod has been marked for deoptimization

    // All this already happens inside a VM_Operation, so we'll do all the work here.
    // Stuff copied from VM_Deoptimize and modified slightly.

    // We do not want any GCs to happen while we are in the middle of this VM operation
    ResourceMark rm;
    DeoptimizationMarker dm;

    // Deoptimize all activations depending on marked nmethods
    Deoptimization::deoptimize_dependents();

    // Make the dependent methods not entrant (in VM_Deoptimize they are made zombies)
    CodeCache::make_marked_nmethods_not_entrant();
  }
}
#endif // HOTSWAP


// Flushes compiled methods dependent on dependee
void Universe::flush_dependents_on_method(methodHandle m_h) {
  // --- Compile_lock is not held. However we are at a safepoint.
  assert_locked_or_safepoint(Compile_lock);

  // CodeCache can only be updated by a thread_in_VM and they will all be
  // stopped dring the safepoint so CodeCache will be safe to update without
  // holding the CodeCache_lock.

  // Compute the dependent nmethods
  if (CodeCache::mark_for_deoptimization(m_h()) > 0) {
    // At least one nmethod has been marked for deoptimization

    // All this already happens inside a VM_Operation, so we'll do all the work here.
    // Stuff copied from VM_Deoptimize and modified slightly.

    // We do not want any GCs to happen while we are in the middle of this VM operation
    ResourceMark rm;
    DeoptimizationMarker dm;

    // Deoptimize all activations depending on marked nmethods
    Deoptimization::deoptimize_dependents();

    // Make the dependent methods not entrant (in VM_Deoptimize they are made zombies)
    CodeCache::make_marked_nmethods_not_entrant();
  }
}

void Universe::print() { print_on(gclog_or_tty); }

void Universe::print_on(outputStream* st) {
  st->print_cr("Heap");
  heap()->print_on(st);
}

void Universe::print_heap_at_SIGBREAK() {
  if (PrintHeapAtSIGBREAK) {
    MutexLocker hl(Heap_lock);
    print_on(tty);
    tty->cr();
    tty->flush();
  }
}

void Universe::print_heap_before_gc(outputStream* st) {
  st->print_cr("{Heap before GC invocations=%u (full %u):",
               heap()->total_collections(),
               heap()->total_full_collections());
  heap()->print_on(st);
}

void Universe::print_heap_after_gc(outputStream* st) {
  st->print_cr("Heap after GC invocations=%u (full %u):",
               heap()->total_collections(),
               heap()->total_full_collections());
  heap()->print_on(st);
  st->print_cr("}");
}

void Universe::verify(bool allow_dirty, bool silent) {
  if (SharedSkipVerify) {
    return;
  }

  // The use of _verify_in_progress is a temporary work around for
  // 6320749.  Don't bother with a creating a class to set and clear
  // it since it is only used in this method and the control flow is
  // straight forward.
  _verify_in_progress = true;

  COMPILER2_PRESENT(
    assert(!DerivedPointerTable::is_active(),
         "DPT should not be active during verification "
         "(of thread stacks below)");
  )

  ResourceMark rm;
  HandleMark hm;  // Handles created during verification can be zapped
  _verify_count++;

  if (!silent) gclog_or_tty->print("[Verifying ");
  if (!silent) gclog_or_tty->print("threads ");
  Threads::verify();
  heap()->verify(allow_dirty, silent);

  if (!silent) gclog_or_tty->print("syms ");
  SymbolTable::verify();
  if (!silent) gclog_or_tty->print("strs ");
  StringTable::verify();
  {
    MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
    if (!silent) gclog_or_tty->print("zone ");
    CodeCache::verify();
  }
  if (!silent) gclog_or_tty->print("dict ");
  SystemDictionary::verify();
  if (!silent) gclog_or_tty->print("hand ");
  JNIHandles::verify();
  if (!silent) gclog_or_tty->print("C-heap ");
  os::check_heap();
  if (!silent) gclog_or_tty->print_cr("]");

  _verify_in_progress = false;
}

// Oop verification (see MacroAssembler::verify_oop)

static uintptr_t _verify_oop_data[2]   = {0, (uintptr_t)-1};
static uintptr_t _verify_klass_data[2] = {0, (uintptr_t)-1};


static void calculate_verify_data(uintptr_t verify_data[2],
                                  HeapWord* low_boundary,
                                  HeapWord* high_boundary) {
  assert(low_boundary < high_boundary, "bad interval");

  // decide which low-order bits we require to be clear:
  size_t alignSize = MinObjAlignmentInBytes;
  size_t min_object_size = oopDesc::header_size();

  // make an inclusive limit:
  uintptr_t max = (uintptr_t)high_boundary - min_object_size*wordSize;
  uintptr_t min = (uintptr_t)low_boundary;
  assert(min < max, "bad interval");
  uintptr_t diff = max ^ min;

  // throw away enough low-order bits to make the diff vanish
  uintptr_t mask = (uintptr_t)(-1);
  while ((mask & diff) != 0)
    mask <<= 1;
  uintptr_t bits = (min & mask);
  assert(bits == (max & mask), "correct mask");
  // check an intermediate value between min and max, just to make sure:
  assert(bits == ((min + (max-min)/2) & mask), "correct mask");

  // require address alignment, too:
  mask |= (alignSize - 1);

  if (!(verify_data[0] == 0 && verify_data[1] == (uintptr_t)-1)) {
    assert(verify_data[0] == mask && verify_data[1] == bits, "mask stability");
  }
  verify_data[0] = mask;
  verify_data[1] = bits;
}


// Oop verification (see MacroAssembler::verify_oop)
#ifndef PRODUCT

uintptr_t Universe::verify_oop_mask() {
  MemRegion m = heap()->reserved_region();
  calculate_verify_data(_verify_oop_data,
                        m.start(),
                        m.end());
  return _verify_oop_data[0];
}



uintptr_t Universe::verify_oop_bits() {
  verify_oop_mask();
  return _verify_oop_data[1];
}


uintptr_t Universe::verify_klass_mask() {
  /* $$$
  // A klass can never live in the new space.  Since the new and old
  // spaces can change size, we must settle for bounds-checking against
  // the bottom of the world, plus the smallest possible new and old
  // space sizes that may arise during execution.
  size_t min_new_size = Universe::new_size();   // in bytes
  size_t min_old_size = Universe::old_size();   // in bytes
  calculate_verify_data(_verify_klass_data,
          (HeapWord*)((uintptr_t)_new_gen->low_boundary + min_new_size + min_old_size),
          _perm_gen->high_boundary);
                        */
  // Why doesn't the above just say that klass's always live in the perm
  // gen?  I'll see if that seems to work...
  MemRegion permanent_reserved;
  switch (Universe::heap()->kind()) {
  default:
    // ???: What if a CollectedHeap doesn't have a permanent generation?
    ShouldNotReachHere();
    break;
  case CollectedHeap::GenCollectedHeap:
  case CollectedHeap::G1CollectedHeap: {
    SharedHeap* sh = (SharedHeap*) Universe::heap();
    permanent_reserved = sh->perm_gen()->reserved();
   break;
  }
#ifndef SERIALGC
  case CollectedHeap::ParallelScavengeHeap: {
    ParallelScavengeHeap* psh = (ParallelScavengeHeap*) Universe::heap();
    permanent_reserved = psh->perm_gen()->reserved();
    break;
  }
#endif // SERIALGC
  }
  calculate_verify_data(_verify_klass_data,
                        permanent_reserved.start(),
                        permanent_reserved.end());

  return _verify_klass_data[0];
}



uintptr_t Universe::verify_klass_bits() {
  verify_klass_mask();
  return _verify_klass_data[1];
}


uintptr_t Universe::verify_mark_mask() {
  return markOopDesc::lock_mask_in_place;
}



uintptr_t Universe::verify_mark_bits() {
  intptr_t mask = verify_mark_mask();
  intptr_t bits = (intptr_t)markOopDesc::prototype();
  assert((bits & ~mask) == 0, "no stray header bits");
  return bits;
}
#endif // PRODUCT


void Universe::compute_verify_oop_data() {
  verify_oop_mask();
  verify_oop_bits();
  verify_mark_mask();
  verify_mark_bits();
  verify_klass_mask();
  verify_klass_bits();
}


void CommonMethodOopCache::init(klassOop k, methodOop m, TRAPS) {
  if (!UseSharedSpaces) {
    _klass = k;
  }
#ifndef PRODUCT
  else {
    // sharing initilization should have already set up _klass
    assert(_klass != NULL, "just checking");
  }
#endif

  _method_idnum = m->method_idnum();
  assert(_method_idnum >= 0, "sanity check");
}


ActiveMethodOopsCache::~ActiveMethodOopsCache() {
  if (_prev_methods != NULL) {
    for (int i = _prev_methods->length() - 1; i >= 0; i--) {
      jweak method_ref = _prev_methods->at(i);
      if (method_ref != NULL) {
        JNIHandles::destroy_weak_global(method_ref);
      }
    }
    delete _prev_methods;
    _prev_methods = NULL;
  }
}


void ActiveMethodOopsCache::add_previous_version(const methodOop method) {
  assert(Thread::current()->is_VM_thread(),
    "only VMThread can add previous versions");

  if (_prev_methods == NULL) {
    // This is the first previous version so make some space.
    // Start with 2 elements under the assumption that the class
    // won't be redefined much.
    _prev_methods = new (ResourceObj::C_HEAP) GrowableArray<jweak>(2, true);
  }

  // RC_TRACE macro has an embedded ResourceMark
  RC_TRACE(0x00000100,
    ("add: %s(%s): adding prev version ref for cached method @%d",
    method->name()->as_C_string(), method->signature()->as_C_string(),
    _prev_methods->length()));

  methodHandle method_h(method);
  jweak method_ref = JNIHandles::make_weak_global(method_h);
  _prev_methods->append(method_ref);

  // Using weak references allows previous versions of the cached
  // method to be GC'ed when they are no longer needed. Since the
  // caller is the VMThread and we are at a safepoint, this is a good
  // time to clear out unused weak references.

  for (int i = _prev_methods->length() - 1; i >= 0; i--) {
    jweak method_ref = _prev_methods->at(i);
    assert(method_ref != NULL, "weak method ref was unexpectedly cleared");
    if (method_ref == NULL) {
      _prev_methods->remove_at(i);
      // Since we are traversing the array backwards, we don't have to
      // do anything special with the index.
      continue;  // robustness
    }

    methodOop m = (methodOop)JNIHandles::resolve(method_ref);
    if (m == NULL) {
      // this method entry has been GC'ed so remove it
      JNIHandles::destroy_weak_global(method_ref);
      _prev_methods->remove_at(i);
    } else {
      // RC_TRACE macro has an embedded ResourceMark
      RC_TRACE(0x00000400, ("add: %s(%s): previous cached method @%d is alive",
        m->name()->as_C_string(), m->signature()->as_C_string(), i));
    }
  }
} // end add_previous_version()


bool ActiveMethodOopsCache::is_same_method(const methodOop method) const {
  instanceKlass* ik = instanceKlass::cast(klass());
  methodOop check_method = ik->method_with_idnum(method_idnum());
  assert(check_method != NULL, "sanity check");
  if (check_method == method) {
    // done with the easy case
    return true;
  }

  if (_prev_methods != NULL) {
    // The cached method has been redefined at least once so search
    // the previous versions for a match.
    for (int i = 0; i < _prev_methods->length(); i++) {
      jweak method_ref = _prev_methods->at(i);
      assert(method_ref != NULL, "weak method ref was unexpectedly cleared");
      if (method_ref == NULL) {
        continue;  // robustness
      }

      check_method = (methodOop)JNIHandles::resolve(method_ref);
      if (check_method == method) {
        // a previous version matches
        return true;
      }
    }
  }

  // either no previous versions or no previous version matched
  return false;
}


methodOop LatestMethodOopCache::get_methodOop() {
  instanceKlass* ik = instanceKlass::cast(klass());
  methodOop m = ik->method_with_idnum(method_idnum());
  assert(m != NULL, "sanity check");
  return m;
}


#ifdef ASSERT
// Release dummy object(s) at bottom of heap
bool Universe::release_fullgc_alot_dummy() {
  MutexLocker ml(FullGCALot_lock);
  if (_fullgc_alot_dummy_array != NULL) {
    if (_fullgc_alot_dummy_next >= _fullgc_alot_dummy_array->length()) {
      // No more dummies to release, release entire array instead
      _fullgc_alot_dummy_array = NULL;
      return false;
    }
    if (!UseConcMarkSweepGC) {
      // Release dummy at bottom of old generation
      _fullgc_alot_dummy_array->obj_at_put(_fullgc_alot_dummy_next++, NULL);
    }
    // Release dummy at bottom of permanent generation
    _fullgc_alot_dummy_array->obj_at_put(_fullgc_alot_dummy_next++, NULL);
  }
  return true;
}

#endif // ASSERT