       1 /*
       2  * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved.
       3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
       4  *
       5  * This code is free software; you can redistribute it and/or modify it
       6  * under the terms of the GNU General Public License version 2 only, as
       7  * published by the Free Software Foundation.
       8  *
       9  * This code is distributed in the hope that it will be useful, but WITHOUT
      10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
      11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
      12  * version 2 for more details (a copy is included in the LICENSE file that
      13  * accompanied this code).
      14  *
      15  * You should have received a copy of the GNU General Public License version
      16  * 2 along with this work; if not, write to the Free Software Foundation,
      17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
      18  *
      19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
      20  * or visit www.oracle.com if you need additional information or have any
      21  * questions.
      22  *
      23  */
      24
      25 #include "precompiled.hpp"
      26 #include "classfile/classLoader.hpp"
      27 #include "classfile/classLoaderData.hpp"
      28 #include "classfile/javaClasses.hpp"
      29 #if INCLUDE_CDS
      30 #include "classfile/sharedClassUtil.hpp"
      31 #endif
      32 #include "classfile/symbolTable.hpp"
      33 #include "classfile/systemDictionary.hpp"
      34 #include "classfile/vmSymbols.hpp"
      35 #include "code/codeCache.hpp"
      36 #include "code/dependencies.hpp"
      37 #include "gc_interface/collectedHeap.inline.hpp"
      38 #include "interpreter/interpreter.hpp"
      39 #include "memory/cardTableModRefBS.hpp"
      40 #include "memory/filemap.hpp"
      41 #include "memory/gcLocker.inline.hpp"
      42 #include "memory/genCollectedHeap.hpp"
      43 #include "memory/genRemSet.hpp"
      44 #include "memory/generation.hpp"
      45 #include "memory/metadataFactory.hpp"
      46 #include "memory/metaspaceShared.hpp"
      47 #include "memory/oopFactory.hpp"
      48 #include "memory/space.hpp"
      49 #include "memory/universe.hpp"
      50 #include "memory/universe.inline.hpp"
      51 #include "oops/constantPool.hpp"
      52 #include "oops/instanceClassLoaderKlass.hpp"
      53 #include "oops/instanceKlass.hpp"
      54 #include "oops/instanceMirrorKlass.hpp"
      55 #include "oops/instanceRefKlass.hpp"
      56 #include "oops/oop.inline.hpp"
      57 #include "oops/typeArrayKlass.hpp"
      58 #include "prims/jvmtiRedefineClassesTrace.hpp"
      59 #include "runtime/arguments.hpp"
      60 #include "runtime/deoptimization.hpp"
      61 #include "runtime/fprofiler.hpp"
      62 #include "runtime/handles.inline.hpp"
      63 #include "runtime/init.hpp"
      64 #include "runtime/java.hpp"
      65 #include "runtime/javaCalls.hpp"
      66 #include "runtime/sharedRuntime.hpp"
      67 #include "runtime/synchronizer.hpp"
      68 #include "runtime/thread.inline.hpp"
      69 #include "runtime/timer.hpp"
      70 #include "runtime/vm_operations.hpp"
      71 #include "services/memoryService.hpp"
      72 #include "utilities/copy.hpp"
      73 #include "utilities/events.hpp"
      74 #include "utilities/hashtable.inline.hpp"
      75 #include "utilities/preserveException.hpp"
      76 #include "utilities/macros.hpp"
      77 #if INCLUDE_ALL_GCS
      78 #include "gc_implementation/concurrentMarkSweep/cmsAdaptiveSizePolicy.hpp"
      79 #include "gc_implementation/concurrentMarkSweep/cmsCollectorPolicy.hpp"
      80 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
      81 #include "gc_implementation/g1/g1CollectorPolicy_ext.hpp"
      82 #include "gc_implementation/parallelScavenge/parallelScavengeHeap.hpp"
      83 #endif // INCLUDE_ALL_GCS
      84
      85 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
      86
      87 // Known objects
      88 Klass* Universe::_boolArrayKlassObj                 = NULL;
      89 Klass* Universe::_byteArrayKlassObj                 = NULL;
      90 Klass* Universe::_charArrayKlassObj                 = NULL;
      91 Klass* Universe::_intArrayKlassObj                  = NULL;
      92 Klass* Universe::_shortArrayKlassObj                = NULL;
      93 Klass* Universe::_longArrayKlassObj                 = NULL;
      94 Klass* Universe::_singleArrayKlassObj               = NULL;
      95 Klass* Universe::_doubleArrayKlassObj               = NULL;
      96 Klass* Universe::_typeArrayKlassObjs[T_VOID+1]      = { NULL /*, NULL...*/ };
      97 Klass* Universe::_objectArrayKlassObj               = NULL;
      98 oop Universe::_int_mirror                             = NULL;
      99 oop Universe::_float_mirror                           = NULL;
     100 oop Universe::_double_mirror                          = NULL;
     101 oop Universe::_byte_mirror                            = NULL;
     102 oop Universe::_bool_mirror                            = NULL;
     103 oop Universe::_char_mirror                            = NULL;
     104 oop Universe::_long_mirror                            = NULL;
     105 oop Universe::_short_mirror                           = NULL;
     106 oop Universe::_void_mirror                            = NULL;
     107 oop Universe::_mirrors[T_VOID+1]                      = { NULL /*, NULL...*/ };
     108 oop Universe::_main_thread_group                      = NULL;
     109 oop Universe::_system_thread_group                    = NULL;
     110 objArrayOop Universe::_the_empty_class_klass_array    = NULL;
     111 Array<Klass*>* Universe::_the_array_interfaces_array = NULL;
     112 oop Universe::_the_null_string                        = NULL;
     113 oop Universe::_the_min_jint_string                   = NULL;
     114 LatestMethodCache* Universe::_finalizer_register_cache = NULL;
     115 LatestMethodCache* Universe::_loader_addClass_cache    = NULL;
     116 LatestMethodCache* Universe::_pd_implies_cache         = NULL;
     117 oop Universe::_out_of_memory_error_java_heap          = NULL;
     118 oop Universe::_out_of_memory_error_metaspace          = NULL;
     119 oop Universe::_out_of_memory_error_class_metaspace    = NULL;
     120 oop Universe::_out_of_memory_error_array_size         = NULL;
     121 oop Universe::_out_of_memory_error_gc_overhead_limit  = NULL;
     122 oop Universe::_out_of_memory_error_realloc_objects    = NULL;
     123 objArrayOop Universe::_preallocated_out_of_memory_error_array = NULL;
     124 volatile jint Universe::_preallocated_out_of_memory_error_avail_count = 0;
     125 bool Universe::_verify_in_progress                    = false;
     126 oop Universe::_null_ptr_exception_instance            = NULL;
     127 oop Universe::_arithmetic_exception_instance          = NULL;
     128 oop Universe::_virtual_machine_error_instance         = NULL;
     129 oop Universe::_vm_exception                           = NULL;
     130 oop Universe::_allocation_context_notification_obj    = NULL;
     131
     132 Method* Universe::_throw_illegal_access_error         = NULL;
     133 Array<int>* Universe::_the_empty_int_array            = NULL;
     134 Array<u2>* Universe::_the_empty_short_array           = NULL;
     135 Array<Klass*>* Universe::_the_empty_klass_array     = NULL;
     136 Array<Method*>* Universe::_the_empty_method_array   = NULL;
     137
     138 // These variables are guarded by FullGCALot_lock.
     139 debug_only(objArrayOop Universe::_fullgc_alot_dummy_array = NULL;)
     140 debug_only(int Universe::_fullgc_alot_dummy_next      = 0;)
     141
     142 // Heap
     143 int             Universe::_verify_count = 0;
     144
     145 int             Universe::_base_vtable_size = 0;
     146 bool            Universe::_bootstrapping = false;
     147 bool            Universe::_fully_initialized = false;
     148
     149 size_t          Universe::_heap_capacity_at_last_gc;
     150 size_t          Universe::_heap_used_at_last_gc = 0;
     151
     152 CollectedHeap*  Universe::_collectedHeap = NULL;
     153
     154 NarrowPtrStruct Universe::_narrow_oop = { NULL, 0, true };
     155 NarrowPtrStruct Universe::_narrow_klass = { NULL, 0, true };
     156 address Universe::_narrow_ptrs_base;
     157
     158 void Universe::basic_type_classes_do(void f(Klass*)) {
     159   f(boolArrayKlassObj());
     160   f(byteArrayKlassObj());
     161   f(charArrayKlassObj());
     162   f(intArrayKlassObj());
     163   f(shortArrayKlassObj());
     164   f(longArrayKlassObj());
     165   f(singleArrayKlassObj());
     166   f(doubleArrayKlassObj());
     167 }
     168
     169 void Universe::oops_do(OopClosure* f, bool do_all) {
     170
     171   f->do_oop((oop*) &_int_mirror);
     172   f->do_oop((oop*) &_float_mirror);
     173   f->do_oop((oop*) &_double_mirror);
     174   f->do_oop((oop*) &_byte_mirror);
     175   f->do_oop((oop*) &_bool_mirror);
     176   f->do_oop((oop*) &_char_mirror);
     177   f->do_oop((oop*) &_long_mirror);
     178   f->do_oop((oop*) &_short_mirror);
     179   f->do_oop((oop*) &_void_mirror);
     180
     181   for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
     182     f->do_oop((oop*) &_mirrors[i]);
     183   }
     184   assert(_mirrors[0] == NULL && _mirrors[T_BOOLEAN - 1] == NULL, "checking");
     185
     186   f->do_oop((oop*)&_the_empty_class_klass_array);
     187   f->do_oop((oop*)&_the_null_string);
     188   f->do_oop((oop*)&_the_min_jint_string);
     189   f->do_oop((oop*)&_out_of_memory_error_java_heap);
     190   f->do_oop((oop*)&_out_of_memory_error_metaspace);
     191   f->do_oop((oop*)&_out_of_memory_error_class_metaspace);
     192   f->do_oop((oop*)&_out_of_memory_error_array_size);
     193   f->do_oop((oop*)&_out_of_memory_error_gc_overhead_limit);
     194   f->do_oop((oop*)&_out_of_memory_error_realloc_objects);
     195     f->do_oop((oop*)&_preallocated_out_of_memory_error_array);
     196   f->do_oop((oop*)&_null_ptr_exception_instance);
     197   f->do_oop((oop*)&_arithmetic_exception_instance);
     198   f->do_oop((oop*)&_virtual_machine_error_instance);
     199   f->do_oop((oop*)&_main_thread_group);
     200   f->do_oop((oop*)&_system_thread_group);
     201   f->do_oop((oop*)&_vm_exception);
     202   f->do_oop((oop*)&_allocation_context_notification_obj);
     203   debug_only(f->do_oop((oop*)&_fullgc_alot_dummy_array);)
     204 }
     205
     206 // Serialize metadata in and out of CDS archive, not oops.
     207 void Universe::serialize(SerializeClosure* f, bool do_all) {
     208
     209   f->do_ptr((void**)&_boolArrayKlassObj);
     210   f->do_ptr((void**)&_byteArrayKlassObj);
     211   f->do_ptr((void**)&_charArrayKlassObj);
     212   f->do_ptr((void**)&_intArrayKlassObj);
     213   f->do_ptr((void**)&_shortArrayKlassObj);
     214   f->do_ptr((void**)&_longArrayKlassObj);
     215   f->do_ptr((void**)&_singleArrayKlassObj);
     216   f->do_ptr((void**)&_doubleArrayKlassObj);
     217   f->do_ptr((void**)&_objectArrayKlassObj);
     218
     219   {
     220     for (int i = 0; i < T_VOID+1; i++) {
     221       if (_typeArrayKlassObjs[i] != NULL) {
     222         assert(i >= T_BOOLEAN, "checking");
     223         f->do_ptr((void**)&_typeArrayKlassObjs[i]);
     224       } else if (do_all) {
     225         f->do_ptr((void**)&_typeArrayKlassObjs[i]);
     226       }
     227     }
     228   }
     229
     230   f->do_ptr((void**)&_the_array_interfaces_array);
     231   f->do_ptr((void**)&_the_empty_int_array);
     232   f->do_ptr((void**)&_the_empty_short_array);
     233   f->do_ptr((void**)&_the_empty_method_array);
     234   f->do_ptr((void**)&_the_empty_klass_array);
     235   _finalizer_register_cache->serialize(f);
     236   _loader_addClass_cache->serialize(f);
     237   _pd_implies_cache->serialize(f);
     238 }
     239
     240 void Universe::check_alignment(uintx size, uintx alignment, const char* name) {
     241   if (size < alignment || size % alignment != 0) {
     242     vm_exit_during_initialization(
     243       err_msg("Size of %s (" UINTX_FORMAT " bytes) must be aligned to " UINTX_FORMAT " bytes", name, size, alignment));
     244   }
     245 }
     246
     247 void initialize_basic_type_klass(Klass* k, TRAPS) {
     248   Klass* ok = SystemDictionary::Object_klass();
     249   if (UseSharedSpaces) {
     250     ClassLoaderData* loader_data = ClassLoaderData::the_null_class_loader_data();
     251     assert(k->super() == ok, "u3");
     252     k->restore_unshareable_info(loader_data, Handle(), CHECK);
     253   } else {
     254     k->initialize_supers(ok, CHECK);
     255   }
     256   k->append_to_sibling_list();
     257 }
     258
     259 void Universe::genesis(TRAPS) {
     260   ResourceMark rm;
     261
     262   { FlagSetting fs(_bootstrapping, true);
     263
     264     { MutexLocker mc(Compile_lock);
     265
     266       // determine base vtable size; without that we cannot create the array klasses
     267       compute_base_vtable_size();
     268
     269       if (!UseSharedSpaces) {
     270         _boolArrayKlassObj      = TypeArrayKlass::create_klass(T_BOOLEAN, sizeof(jboolean), CHECK);
     271         _charArrayKlassObj      = TypeArrayKlass::create_klass(T_CHAR,    sizeof(jchar),    CHECK);
     272         _singleArrayKlassObj    = TypeArrayKlass::create_klass(T_FLOAT,   sizeof(jfloat),   CHECK);
     273         _doubleArrayKlassObj    = TypeArrayKlass::create_klass(T_DOUBLE,  sizeof(jdouble),  CHECK);
     274         _byteArrayKlassObj      = TypeArrayKlass::create_klass(T_BYTE,    sizeof(jbyte),    CHECK);
     275         _shortArrayKlassObj     = TypeArrayKlass::create_klass(T_SHORT,   sizeof(jshort),   CHECK);
     276         _intArrayKlassObj       = TypeArrayKlass::create_klass(T_INT,     sizeof(jint),     CHECK);
     277         _longArrayKlassObj      = TypeArrayKlass::create_klass(T_LONG,    sizeof(jlong),    CHECK);
     278
     279         _typeArrayKlassObjs[T_BOOLEAN] = _boolArrayKlassObj;
     280         _typeArrayKlassObjs[T_CHAR]    = _charArrayKlassObj;
     281         _typeArrayKlassObjs[T_FLOAT]   = _singleArrayKlassObj;
     282         _typeArrayKlassObjs[T_DOUBLE]  = _doubleArrayKlassObj;
     283         _typeArrayKlassObjs[T_BYTE]    = _byteArrayKlassObj;
     284         _typeArrayKlassObjs[T_SHORT]   = _shortArrayKlassObj;
     285         _typeArrayKlassObjs[T_INT]     = _intArrayKlassObj;
     286         _typeArrayKlassObjs[T_LONG]    = _longArrayKlassObj;
     287
     288         ClassLoaderData* null_cld = ClassLoaderData::the_null_class_loader_data();
     289
     290         _the_array_interfaces_array = MetadataFactory::new_array<Klass*>(null_cld, 2, NULL, CHECK);
     291         _the_empty_int_array        = MetadataFactory::new_array<int>(null_cld, 0, CHECK);
     292         _the_empty_short_array      = MetadataFactory::new_array<u2>(null_cld, 0, CHECK);
     293         _the_empty_method_array     = MetadataFactory::new_array<Method*>(null_cld, 0, CHECK);
     294         _the_empty_klass_array      = MetadataFactory::new_array<Klass*>(null_cld, 0, CHECK);
     295       }
     296     }
     297
     298     vmSymbols::initialize(CHECK);
     299
     300     SystemDictionary::initialize(CHECK);
     301
     302     Klass* ok = SystemDictionary::Object_klass();
     303
     304     _the_null_string            = StringTable::intern("null", CHECK);
     305     _the_min_jint_string       = StringTable::intern("-2147483648", CHECK);
     306
     307     if (UseSharedSpaces) {
     308       // Verify shared interfaces array.
     309       assert(_the_array_interfaces_array->at(0) ==
     310              SystemDictionary::Cloneable_klass(), "u3");
     311       assert(_the_array_interfaces_array->at(1) ==
     312              SystemDictionary::Serializable_klass(), "u3");
     313     } else {
     314       // Set up shared interfaces array.  (Do this before supers are set up.)
     315       _the_array_interfaces_array->at_put(0, SystemDictionary::Cloneable_klass());
     316       _the_array_interfaces_array->at_put(1, SystemDictionary::Serializable_klass());
     317     }
     318
     319     initialize_basic_type_klass(boolArrayKlassObj(), CHECK);
     320     initialize_basic_type_klass(charArrayKlassObj(), CHECK);
     321     initialize_basic_type_klass(singleArrayKlassObj(), CHECK);
     322     initialize_basic_type_klass(doubleArrayKlassObj(), CHECK);
     323     initialize_basic_type_klass(byteArrayKlassObj(), CHECK);
     324     initialize_basic_type_klass(shortArrayKlassObj(), CHECK);
     325     initialize_basic_type_klass(intArrayKlassObj(), CHECK);
     326     initialize_basic_type_klass(longArrayKlassObj(), CHECK);
     327   } // end of core bootstrapping
     328
     329   // Maybe this could be lifted up now that object array can be initialized
     330   // during the bootstrapping.
     331
     332   // OLD
     333   // Initialize _objectArrayKlass after core bootstraping to make
     334   // sure the super class is set up properly for _objectArrayKlass.
     335   // ---
     336   // NEW
     337   // Since some of the old system object arrays have been converted to
     338   // ordinary object arrays, _objectArrayKlass will be loaded when
     339   // SystemDictionary::initialize(CHECK); is run. See the extra check
     340   // for Object_klass_loaded in objArrayKlassKlass::allocate_objArray_klass_impl.
     341   _objectArrayKlassObj = InstanceKlass::
     342     cast(SystemDictionary::Object_klass())->array_klass(1, CHECK);
     343   // OLD
     344   // Add the class to the class hierarchy manually to make sure that
     345   // its vtable is initialized after core bootstrapping is completed.
     346   // ---
     347   // New
     348   // Have already been initialized.
     349   _objectArrayKlassObj->append_to_sibling_list();
     350
     351   // Compute is_jdk version flags.
     352   // Only 1.3 or later has the java.lang.Shutdown class.
     353   // Only 1.4 or later has the java.lang.CharSequence interface.
     354   // Only 1.5 or later has the java.lang.management.MemoryUsage class.
     355   if (JDK_Version::is_partially_initialized()) {
     356     uint8_t jdk_version;
     357     Klass* k = SystemDictionary::resolve_or_null(
     358         vmSymbols::java_lang_management_MemoryUsage(), THREAD);
     359     CLEAR_PENDING_EXCEPTION; // ignore exceptions
     360     if (k == NULL) {
     361       k = SystemDictionary::resolve_or_null(
     362           vmSymbols::java_lang_CharSequence(), THREAD);
     363       CLEAR_PENDING_EXCEPTION; // ignore exceptions
     364       if (k == NULL) {
     365         k = SystemDictionary::resolve_or_null(
     366             vmSymbols::java_lang_Shutdown(), THREAD);
     367         CLEAR_PENDING_EXCEPTION; // ignore exceptions
     368         if (k == NULL) {
     369           jdk_version = 2;
     370         } else {
     371           jdk_version = 3;
     372         }
     373       } else {
     374         jdk_version = 4;
     375       }
     376     } else {
     377       jdk_version = 5;
     378     }
     379     JDK_Version::fully_initialize(jdk_version);
     380   }
     381
     382   #ifdef ASSERT
     383   if (FullGCALot) {
     384     // Allocate an array of dummy objects.
     385     // We'd like these to be at the bottom of the old generation,
     386     // so that when we free one and then collect,
     387     // (almost) the whole heap moves
     388     // and we find out if we actually update all the oops correctly.
     389     // But we can't allocate directly in the old generation,
     390     // so we allocate wherever, and hope that the first collection
     391     // moves these objects to the bottom of the old generation.
     392     // We can allocate directly in the permanent generation, so we do.
     393     int size;
     394     if (UseConcMarkSweepGC) {
     395       warning("Using +FullGCALot with concurrent mark sweep gc "
     396               "will not force all objects to relocate");
     397       size = FullGCALotDummies;
     398     } else {
     399       size = FullGCALotDummies * 2;
     400     }
     401     objArrayOop    naked_array = oopFactory::new_objArray(SystemDictionary::Object_klass(), size, CHECK);
     402     objArrayHandle dummy_array(THREAD, naked_array);
     403     int i = 0;
     404     while (i < size) {
     405         // Allocate dummy in old generation
     406       oop dummy = InstanceKlass::cast(SystemDictionary::Object_klass())->allocate_instance(CHECK);
     407       dummy_array->obj_at_put(i++, dummy);
     408     }
     409     {
     410       // Only modify the global variable inside the mutex.
     411       // If we had a race to here, the other dummy_array instances
     412       // and their elements just get dropped on the floor, which is fine.
     413       MutexLocker ml(FullGCALot_lock);
     414       if (_fullgc_alot_dummy_array == NULL) {
     415         _fullgc_alot_dummy_array = dummy_array();
     416       }
     417     }
     418     assert(i == _fullgc_alot_dummy_array->length(), "just checking");
     419   }
     420   #endif
     421
     422   // Initialize dependency array for null class loader
     423   ClassLoaderData::the_null_class_loader_data()->init_dependencies(CHECK);
     424
     425 }
     426
     427 // CDS support for patching vtables in metadata in the shared archive.
     428 // All types inherited from Metadata have vtables, but not types inherited
     429 // from MetaspaceObj, because the latter does not have virtual functions.
     430 // If the metadata type has a vtable, it cannot be shared in the read-only
     431 // section of the CDS archive, because the vtable pointer is patched.
     432 static inline void add_vtable(void** list, int* n, void* o, int count) {
     433   guarantee((*n) < count, "vtable list too small");
     434   void* vtable = dereference_vptr(o);
     435   assert(*(void**)(vtable) != NULL, "invalid vtable");
     436   list[(*n)++] = vtable;
     437 }
     438
     439 void Universe::init_self_patching_vtbl_list(void** list, int count) {
     440   int n = 0;
     441   { InstanceKlass o;          add_vtable(list, &n, &o, count); }
     442   { InstanceClassLoaderKlass o; add_vtable(list, &n, &o, count); }
     443   { InstanceMirrorKlass o;    add_vtable(list, &n, &o, count); }
     444   { InstanceRefKlass o;       add_vtable(list, &n, &o, count); }
     445   { TypeArrayKlass o;         add_vtable(list, &n, &o, count); }
     446   { ObjArrayKlass o;          add_vtable(list, &n, &o, count); }
     447   { Method o;                 add_vtable(list, &n, &o, count); }
     448   { ConstantPool o;           add_vtable(list, &n, &o, count); }
     449 }
     450
     451 void Universe::initialize_basic_type_mirrors(TRAPS) {
     452     assert(_int_mirror==NULL, "basic type mirrors already initialized");
     453     _int_mirror     =
     454       java_lang_Class::create_basic_type_mirror("int",    T_INT, CHECK);
     455     _float_mirror   =
     456       java_lang_Class::create_basic_type_mirror("float",  T_FLOAT,   CHECK);
     457     _double_mirror  =
     458       java_lang_Class::create_basic_type_mirror("double", T_DOUBLE,  CHECK);
     459     _byte_mirror    =
     460       java_lang_Class::create_basic_type_mirror("byte",   T_BYTE, CHECK);
     461     _bool_mirror    =
     462       java_lang_Class::create_basic_type_mirror("boolean",T_BOOLEAN, CHECK);
     463     _char_mirror    =
     464       java_lang_Class::create_basic_type_mirror("char",   T_CHAR, CHECK);
     465     _long_mirror    =
     466       java_lang_Class::create_basic_type_mirror("long",   T_LONG, CHECK);
     467     _short_mirror   =
     468       java_lang_Class::create_basic_type_mirror("short",  T_SHORT,   CHECK);
     469     _void_mirror    =
     470       java_lang_Class::create_basic_type_mirror("void",   T_VOID, CHECK);
     471
     472     _mirrors[T_INT]     = _int_mirror;
     473     _mirrors[T_FLOAT]   = _float_mirror;
     474     _mirrors[T_DOUBLE]  = _double_mirror;
     475     _mirrors[T_BYTE]    = _byte_mirror;
     476     _mirrors[T_BOOLEAN] = _bool_mirror;
     477     _mirrors[T_CHAR]    = _char_mirror;
     478     _mirrors[T_LONG]    = _long_mirror;
     479     _mirrors[T_SHORT]   = _short_mirror;
     480     _mirrors[T_VOID]    = _void_mirror;
     481   //_mirrors[T_OBJECT]  = InstanceKlass::cast(_object_klass)->java_mirror();
     482   //_mirrors[T_ARRAY]   = InstanceKlass::cast(_object_klass)->java_mirror();
     483 }
     484
     485 void Universe::fixup_mirrors(TRAPS) {
     486   // Bootstrap problem: all classes gets a mirror (java.lang.Class instance) assigned eagerly,
     487   // but we cannot do that for classes created before java.lang.Class is loaded. Here we simply
     488   // walk over permanent objects created so far (mostly classes) and fixup their mirrors. Note
     489   // that the number of objects allocated at this point is very small.
     490   assert(SystemDictionary::Class_klass_loaded(), "java.lang.Class should be loaded");
     491   HandleMark hm(THREAD);
     492   // Cache the start of the static fields
     493   InstanceMirrorKlass::init_offset_of_static_fields();
     494
     495   GrowableArray <Klass*>* list = java_lang_Class::fixup_mirror_list();
     496   int list_length = list->length();
     497   for (int i = 0; i < list_length; i++) {
     498     Klass* k = list->at(i);
     499     assert(k->is_klass(), "List should only hold classes");
     500     EXCEPTION_MARK;
     501     KlassHandle kh(THREAD, k);
     502     java_lang_Class::fixup_mirror(kh, CATCH);
     503 }
     504   delete java_lang_Class::fixup_mirror_list();
     505   java_lang_Class::set_fixup_mirror_list(NULL);
     506 }
     507
     508 static bool has_run_finalizers_on_exit = false;
     509
     510 void Universe::run_finalizers_on_exit() {
     511   if (has_run_finalizers_on_exit) return;
     512   has_run_finalizers_on_exit = true;
     513
     514   // Called on VM exit. This ought to be run in a separate thread.
     515   if (TraceReferenceGC) tty->print_cr("Callback to run finalizers on exit");
     516   {
     517     PRESERVE_EXCEPTION_MARK;
     518     KlassHandle finalizer_klass(THREAD, SystemDictionary::Finalizer_klass());
     519     JavaValue result(T_VOID);
     520     JavaCalls::call_static(
     521       &result,
     522       finalizer_klass,
     523       vmSymbols::run_finalizers_on_exit_name(),
     524       vmSymbols::void_method_signature(),
     525       THREAD
     526     );
     527     // Ignore any pending exceptions
     528     CLEAR_PENDING_EXCEPTION;
     529   }
     530 }
     531
     532
     533 // initialize_vtable could cause gc if
     534 // 1) we specified true to initialize_vtable and
     535 // 2) this ran after gc was enabled
     536 // In case those ever change we use handles for oops
     537 void Universe::reinitialize_vtable_of(KlassHandle k_h, TRAPS) {
     538   // init vtable of k and all subclasses
     539   Klass* ko = k_h();
     540   klassVtable* vt = ko->vtable();
     541   if (vt) vt->initialize_vtable(false, CHECK);
     542   if (ko->oop_is_instance()) {
     543     InstanceKlass* ik = (InstanceKlass*)ko;
     544     for (KlassHandle s_h(THREAD, ik->subklass());
     545          s_h() != NULL;
     546          s_h = KlassHandle(THREAD, s_h()->next_sibling())) {
     547       reinitialize_vtable_of(s_h, CHECK);
     548     }
     549   }
     550 }
     551
     552
     553 void initialize_itable_for_klass(Klass* k, TRAPS) {
     554   InstanceKlass::cast(k)->itable()->initialize_itable(false, CHECK);
     555 }
     556
     557
     558 void Universe::reinitialize_itables(TRAPS) {
     559   SystemDictionary::classes_do(initialize_itable_for_klass, CHECK);
     560
     561 }
     562
     563
     564 bool Universe::on_page_boundary(void* addr) {
     565   return ((uintptr_t) addr) % os::vm_page_size() == 0;
     566 }
     567
     568
     569 bool Universe::should_fill_in_stack_trace(Handle throwable) {
     570   // never attempt to fill in the stack trace of preallocated errors that do not have
     571   // backtrace. These errors are kept alive forever and may be "re-used" when all
     572   // preallocated errors with backtrace have been consumed. Also need to avoid
     573   // a potential loop which could happen if an out of memory occurs when attempting
     574   // to allocate the backtrace.
     575   return ((throwable() != Universe::_out_of_memory_error_java_heap) &&
     576           (throwable() != Universe::_out_of_memory_error_metaspace)  &&
     577           (throwable() != Universe::_out_of_memory_error_class_metaspace)  &&
     578           (throwable() != Universe::_out_of_memory_error_array_size) &&
     579           (throwable() != Universe::_out_of_memory_error_gc_overhead_limit) &&
     580           (throwable() != Universe::_out_of_memory_error_realloc_objects));
     581 }
     582
     583
     584 oop Universe::gen_out_of_memory_error(oop default_err) {
     585   // generate an out of memory error:
     586   // - if there is a preallocated error with backtrace available then return it wth
     587   //   a filled in stack trace.
     588   // - if there are no preallocated errors with backtrace available then return
     589   //   an error without backtrace.
     590   int next;
     591   if (_preallocated_out_of_memory_error_avail_count > 0) {
     592     next = (int)Atomic::add(-1, &_preallocated_out_of_memory_error_avail_count);
     593     assert(next < (int)PreallocatedOutOfMemoryErrorCount, "avail count is corrupt");
     594   } else {
     595     next = -1;
     596   }
     597   if (next < 0) {
     598     // all preallocated errors have been used.
     599     // return default
     600     return default_err;
     601   } else {
     602     // get the error object at the slot and set set it to NULL so that the
     603     // array isn't keeping it alive anymore.
     604     oop exc = preallocated_out_of_memory_errors()->obj_at(next);
     605     assert(exc != NULL, "slot has been used already");
     606     preallocated_out_of_memory_errors()->obj_at_put(next, NULL);
     607
     608     // use the message from the default error
     609     oop msg = java_lang_Throwable::message(default_err);
     610     assert(msg != NULL, "no message");
     611     java_lang_Throwable::set_message(exc, msg);
     612
     613     // populate the stack trace and return it.
     614     java_lang_Throwable::fill_in_stack_trace_of_preallocated_backtrace(exc);
     615     return exc;
     616   }
     617 }
     618
     619 intptr_t Universe::_non_oop_bits = 0;
     620
     621 void* Universe::non_oop_word() {
     622   // Neither the high bits nor the low bits of this value is allowed
     623   // to look like (respectively) the high or low bits of a real oop.
     624   //
     625   // High and low are CPU-specific notions, but low always includes
     626   // the low-order bit.  Since oops are always aligned at least mod 4,
     627   // setting the low-order bit will ensure that the low half of the
     628   // word will never look like that of a real oop.
     629   //
     630   // Using the OS-supplied non-memory-address word (usually 0 or -1)
     631   // will take care of the high bits, however many there are.
     632
     633   if (_non_oop_bits == 0) {
     634     _non_oop_bits = (intptr_t)os::non_memory_address_word() | 1;
     635   }
     636
     637   return (void*)_non_oop_bits;
     638 }
     639
     640 jint universe_init() {
     641   assert(!Universe::_fully_initialized, "called after initialize_vtables");
     642   guarantee(1 << LogHeapWordSize == sizeof(HeapWord),
     643          "LogHeapWordSize is incorrect.");
     644   guarantee(sizeof(oop) >= sizeof(HeapWord), "HeapWord larger than oop?");
     645   guarantee(sizeof(oop) % sizeof(HeapWord) == 0,
     646             "oop size is not not a multiple of HeapWord size");
     647   TraceTime timer("Genesis", TraceStartupTime);
     648   JavaClasses::compute_hard_coded_offsets();
     649
     650   jint status = Universe::initialize_heap();
     651   if (status != JNI_OK) {
     652     return status;
     653   }
     654
     655   Metaspace::global_initialize();
     656
     657   // Create memory for metadata.  Must be after initializing heap for
     658   // DumpSharedSpaces.
     659   ClassLoaderData::init_null_class_loader_data();
     660
     661   // We have a heap so create the Method* caches before
     662   // Metaspace::initialize_shared_spaces() tries to populate them.
     663   Universe::_finalizer_register_cache = new LatestMethodCache();
     664   Universe::_loader_addClass_cache    = new LatestMethodCache();
     665   Universe::_pd_implies_cache         = new LatestMethodCache();
     666
     667   if (UseSharedSpaces) {
     668     // Read the data structures supporting the shared spaces (shared
     669     // system dictionary, symbol table, etc.).  After that, access to
     670     // the file (other than the mapped regions) is no longer needed, and
     671     // the file is closed. Closing the file does not affect the
     672     // currently mapped regions.
     673     MetaspaceShared::initialize_shared_spaces();
     674     StringTable::create_table();
     675   } else {
     676 #ifdef PRINT_HASHTABLES_CREATION
     677   fprintf(stderr, ">>>>> Creating SymbolTable\n");
     678 #endif
     679     SymbolTable::create_table();
     680 #ifdef PRINT_HASHTABLES_CREATION
     681   fprintf(stderr, ">>>>> Creating StringTable\n");
     682 #endif
     683     StringTable::create_table();
     684 #ifdef PRINT_HASHTABLES_CREATION
     685   fprintf(stderr, ">>>>> Creating ClassLoader PackageHashtable\n");
     686 #endif
     687     ClassLoader::create_package_info_table();
     688
     689     if (DumpSharedSpaces) {
     690       MetaspaceShared::prepare_for_dumping();
     691     }
     692   }
     693
     694   return JNI_OK;
     695 }
     696
     697 // Choose the heap base address and oop encoding mode
     698 // when compressed oops are used:
     699 // Unscaled  - Use 32-bits oops without encoding when
     700 //     NarrowOopHeapBaseMin + heap_size < 4Gb
     701 // ZeroBased - Use zero based compressed oops with encoding when
     702 //     NarrowOopHeapBaseMin + heap_size < 32Gb
     703 // HeapBased - Use compressed oops with heap base + encoding.
     704
     705 // 4Gb
     706 static const uint64_t UnscaledOopHeapMax = (uint64_t(max_juint) + 1);
     707 // 32Gb
     708 // OopEncodingHeapMax == UnscaledOopHeapMax << LogMinObjAlignmentInBytes;
     709
     710 char* Universe::preferred_heap_base(size_t heap_size, size_t alignment, NARROW_OOP_MODE mode) {
     711   assert(is_size_aligned((size_t)OopEncodingHeapMax, alignment), "Must be");
     712   assert(is_size_aligned((size_t)UnscaledOopHeapMax, alignment), "Must be");
     713   assert(is_size_aligned(heap_size, alignment), "Must be");
     714
     715   uintx heap_base_min_address_aligned = align_size_up(HeapBaseMinAddress, alignment);
     716
     717   size_t base = 0;
     718 #ifdef _LP64
     719   if (UseCompressedOops) {
     720     assert(mode == UnscaledNarrowOop  ||
     721            mode == ZeroBasedNarrowOop ||
     722            mode == HeapBasedNarrowOop, "mode is invalid");
     723     const size_t total_size = heap_size + heap_base_min_address_aligned;
     724     // Return specified base for the first request.
     725     if (!FLAG_IS_DEFAULT(HeapBaseMinAddress) && (mode == UnscaledNarrowOop)) {
     726       base = heap_base_min_address_aligned;
     727
     728     // If the total size is small enough to allow UnscaledNarrowOop then
     729     // just use UnscaledNarrowOop.
     730     } else if ((total_size <= OopEncodingHeapMax) && (mode != HeapBasedNarrowOop)) {
     731       if ((total_size <= UnscaledOopHeapMax) && (mode == UnscaledNarrowOop) &&
     732           (Universe::narrow_oop_shift() == 0)) {
     733         // Use 32-bits oops without encoding and
     734         // place heap's top on the 4Gb boundary
     735         base = (UnscaledOopHeapMax - heap_size);
     736       } else {
     737         // Can't reserve with NarrowOopShift == 0
     738         Universe::set_narrow_oop_shift(LogMinObjAlignmentInBytes);
     739
     740         if (mode == UnscaledNarrowOop ||
     741             mode == ZeroBasedNarrowOop && total_size <= UnscaledOopHeapMax) {
     742
     743           // Use zero based compressed oops with encoding and
     744           // place heap's top on the 32Gb boundary in case
     745           // total_size > 4Gb or failed to reserve below 4Gb.
     746           uint64_t heap_top = OopEncodingHeapMax;
     747
     748           // For small heaps, save some space for compressed class pointer
     749           // space so it can be decoded with no base.
     750           if (UseCompressedClassPointers && !UseSharedSpaces &&
     751               OopEncodingHeapMax <= 32*G) {
     752
     753             uint64_t class_space = align_size_up(CompressedClassSpaceSize, alignment);
     754             assert(is_size_aligned((size_t)OopEncodingHeapMax-class_space,
     755                    alignment), "difference must be aligned too");
     756             uint64_t new_top = OopEncodingHeapMax-class_space;
     757
     758             if (total_size <= new_top) {
     759               heap_top = new_top;
     760             }
     761           }
     762
     763           // Align base to the adjusted top of the heap
     764           base = heap_top - heap_size;
     765         }
     766       }
     767     } else {
     768       // UnscaledNarrowOop encoding didn't work, and no base was found for ZeroBasedOops or
     769       // HeapBasedNarrowOop encoding was requested.  So, can't reserve below 32Gb.
     770       Universe::set_narrow_oop_shift(LogMinObjAlignmentInBytes);
     771     }
     772
     773     // Set narrow_oop_base and narrow_oop_use_implicit_null_checks
     774     // used in ReservedHeapSpace() constructors.
     775     // The final values will be set in initialize_heap() below.
     776     if ((base != 0) && ((base + heap_size) <= OopEncodingHeapMax)) {
     777       // Use zero based compressed oops
     778       Universe::set_narrow_oop_base(NULL);
     779       // Don't need guard page for implicit checks in indexed
     780       // addressing mode with zero based Compressed Oops.
     781       Universe::set_narrow_oop_use_implicit_null_checks(true);
     782     } else {
     783       // Set to a non-NULL value so the ReservedSpace ctor computes
     784       // the correct no-access prefix.
     785       // The final value will be set in initialize_heap() below.
     786       Universe::set_narrow_oop_base((address)UnscaledOopHeapMax);
     787 #if defined(_WIN64) || defined(AIX)
     788       if (UseLargePages) {
     789         // Cannot allocate guard pages for implicit checks in indexed
     790         // addressing mode when large pages are specified on windows.
     791         Universe::set_narrow_oop_use_implicit_null_checks(false);
     792       }
     793 #endif //  _WIN64
     794     }
     795   }
     796 #endif
     797
     798   assert(is_ptr_aligned((char*)base, alignment), "Must be");
     799   return (char*)base; // also return NULL (don't care) for 32-bit VM
     800 }
     801
     802 jint Universe::initialize_heap() {
     803
     804   if (UseParallelGC) {
     805 #if INCLUDE_ALL_GCS
     806     Universe::_collectedHeap = new ParallelScavengeHeap();
     807 #else  // INCLUDE_ALL_GCS
     808     fatal("UseParallelGC not supported in this VM.");
     809 #endif // INCLUDE_ALL_GCS
     810
     811   } else if (UseG1GC) {
     812 #if INCLUDE_ALL_GCS
     813     G1CollectorPolicyExt* g1p = new G1CollectorPolicyExt();
     814     g1p->initialize_all();
     815     G1CollectedHeap* g1h = new G1CollectedHeap(g1p);
     816     Universe::_collectedHeap = g1h;
     817 #else  // INCLUDE_ALL_GCS
     818     fatal("UseG1GC not supported in java kernel vm.");
     819 #endif // INCLUDE_ALL_GCS
     820
     821   } else {
     822     GenCollectorPolicy *gc_policy;
     823
     824     if (UseSerialGC) {
     825       gc_policy = new MarkSweepPolicy();
     826     } else if (UseConcMarkSweepGC) {
     827 #if INCLUDE_ALL_GCS
     828       if (UseAdaptiveSizePolicy) {
     829         gc_policy = new ASConcurrentMarkSweepPolicy();
     830       } else {
     831         gc_policy = new ConcurrentMarkSweepPolicy();
     832       }
     833 #else  // INCLUDE_ALL_GCS
     834     fatal("UseConcMarkSweepGC not supported in this VM.");
     835 #endif // INCLUDE_ALL_GCS
     836     } else { // default old generation
     837       gc_policy = new MarkSweepPolicy();
     838     }
     839     gc_policy->initialize_all();
     840
     841     Universe::_collectedHeap = new GenCollectedHeap(gc_policy);
     842   }
     843
     844   ThreadLocalAllocBuffer::set_max_size(Universe::heap()->max_tlab_size());
     845
     846   jint status = Universe::heap()->initialize();
     847   if (status != JNI_OK) {
     848     return status;
     849   }
     850
     851 #ifdef _LP64
     852   if (UseCompressedOops) {
     853     // Subtract a page because something can get allocated at heap base.
     854     // This also makes implicit null checking work, because the
     855     // memory+1 page below heap_base needs to cause a signal.
     856     // See needs_explicit_null_check.
     857     // Only set the heap base for compressed oops because it indicates
     858     // compressed oops for pstack code.
     859     bool verbose = PrintCompressedOopsMode || (PrintMiscellaneous && Verbose);
     860     if (verbose) {
     861       tty->cr();
     862       tty->print("heap address: " PTR_FORMAT ", size: " SIZE_FORMAT " MB",
     863                  Universe::heap()->base(), Universe::heap()->reserved_region().byte_size()/M);
     864     }
     865     if (((uint64_t)Universe::heap()->reserved_region().end() > OopEncodingHeapMax)) {
     866       // Can't reserve heap below 32Gb.
     867       // keep the Universe::narrow_oop_base() set in Universe::reserve_heap()
     868       Universe::set_narrow_oop_shift(LogMinObjAlignmentInBytes);
     869 #ifdef AIX
     870       // There is no protected page before the heap. This assures all oops
     871       // are decoded so that NULL is preserved, so this page will not be accessed.
     872       Universe::set_narrow_oop_use_implicit_null_checks(false);
     873 #endif
     874       if (verbose) {
     875         tty->print(", %s: "PTR_FORMAT,
     876             narrow_oop_mode_to_string(HeapBasedNarrowOop),
     877             Universe::narrow_oop_base());
     878       }
     879     } else {
     880       Universe::set_narrow_oop_base(0);
     881       if (verbose) {
     882         tty->print(", %s", narrow_oop_mode_to_string(ZeroBasedNarrowOop));
     883       }
     884 #ifdef _WIN64
     885       if (!Universe::narrow_oop_use_implicit_null_checks()) {
     886         // Don't need guard page for implicit checks in indexed addressing
     887         // mode with zero based Compressed Oops.
     888         Universe::set_narrow_oop_use_implicit_null_checks(true);
     889       }
     890 #endif //  _WIN64
     891       if((uint64_t)Universe::heap()->reserved_region().end() > UnscaledOopHeapMax) {
     892         // Can't reserve heap below 4Gb.
     893         Universe::set_narrow_oop_shift(LogMinObjAlignmentInBytes);
     894       } else {
     895         Universe::set_narrow_oop_shift(0);
     896         if (verbose) {
     897           tty->print(", %s", narrow_oop_mode_to_string(UnscaledNarrowOop));
     898         }
     899       }
     900     }
     901
     902     if (verbose) {
     903       tty->cr();
     904       tty->cr();
     905     }
     906     Universe::set_narrow_ptrs_base(Universe::narrow_oop_base());
     907   }
     908   // Universe::narrow_oop_base() is one page below the heap.
     909   assert((intptr_t)Universe::narrow_oop_base() <= (intptr_t)(Universe::heap()->base() -
     910          os::vm_page_size()) ||
     911          Universe::narrow_oop_base() == NULL, "invalid value");
     912   assert(Universe::narrow_oop_shift() == LogMinObjAlignmentInBytes ||
     913          Universe::narrow_oop_shift() == 0, "invalid value");
     914 #endif
     915
     916   // We will never reach the CATCH below since Exceptions::_throw will cause
     917   // the VM to exit if an exception is thrown during initialization
     918
     919   if (UseTLAB) {
     920     assert(Universe::heap()->supports_tlab_allocation(),
     921            "Should support thread-local allocation buffers");
     922     ThreadLocalAllocBuffer::startup_initialization();
     923   }
     924   return JNI_OK;
     925 }
     926
     927
     928 // Reserve the Java heap, which is now the same for all GCs.
     929 ReservedSpace Universe::reserve_heap(size_t heap_size, size_t alignment) {
     930   assert(alignment <= Arguments::conservative_max_heap_alignment(),
     931       err_msg("actual alignment "SIZE_FORMAT" must be within maximum heap alignment "SIZE_FORMAT,
     932           alignment, Arguments::conservative_max_heap_alignment()));
     933   size_t total_reserved = align_size_up(heap_size, alignment);
     934   assert(!UseCompressedOops || (total_reserved <= (OopEncodingHeapMax - os::vm_page_size())),
     935       "heap size is too big for compressed oops");
     936
     937   bool use_large_pages = UseLargePages && is_size_aligned(alignment, os::large_page_size());
     938   assert(!UseLargePages
     939       || UseParallelGC
     940       || use_large_pages, "Wrong alignment to use large pages");
     941
     942   char* addr = Universe::preferred_heap_base(total_reserved, alignment, Universe::UnscaledNarrowOop);
     943
     944   ReservedHeapSpace total_rs(total_reserved, alignment, use_large_pages, addr);
     945
     946   if (UseCompressedOops) {
     947     if (addr != NULL && !total_rs.is_reserved()) {
     948       // Failed to reserve at specified address - the requested memory
     949       // region is taken already, for example, by 'java' launcher.
     950       // Try again to reserver heap higher.
     951       addr = Universe::preferred_heap_base(total_reserved, alignment, Universe::ZeroBasedNarrowOop);
     952
     953       ReservedHeapSpace total_rs0(total_reserved, alignment,
     954           use_large_pages, addr);
     955
     956       if (addr != NULL && !total_rs0.is_reserved()) {
     957         // Failed to reserve at specified address again - give up.
     958         addr = Universe::preferred_heap_base(total_reserved, alignment, Universe::HeapBasedNarrowOop);
     959         assert(addr == NULL, "");
     960
     961         ReservedHeapSpace total_rs1(total_reserved, alignment,
     962             use_large_pages, addr);
     963         total_rs = total_rs1;
     964       } else {
     965         total_rs = total_rs0;
     966       }
     967     }
     968   }
     969
     970   if (!total_rs.is_reserved()) {
     971     vm_exit_during_initialization(err_msg("Could not reserve enough space for " SIZE_FORMAT "KB object heap", total_reserved/K));
     972     return total_rs;
     973   }
     974
     975   if (UseCompressedOops) {
     976     // Universe::initialize_heap() will reset this to NULL if unscaled
     977     // or zero-based narrow oops are actually used.
     978     address base = (address)(total_rs.base() - os::vm_page_size());
     979     Universe::set_narrow_oop_base(base);
     980   }
     981   return total_rs;
     982 }
     983
     984
     985 // It's the caller's responsibility to ensure glitch-freedom
     986 // (if required).
     987 void Universe::update_heap_info_at_gc() {
     988   _heap_capacity_at_last_gc = heap()->capacity();
     989   _heap_used_at_last_gc     = heap()->used();
     990 }
     991
     992
     993 const char* Universe::narrow_oop_mode_to_string(Universe::NARROW_OOP_MODE mode) {
     994   switch (mode) {
     995     case UnscaledNarrowOop:
     996       return "32-bits Oops";
     997     case ZeroBasedNarrowOop:
     998       return "zero based Compressed Oops";
     999     case HeapBasedNarrowOop:
    1000       return "Compressed Oops with base";
    1001   }
    1002
    1003   ShouldNotReachHere();
    1004   return "";
    1005 }
    1006
    1007
    1008 Universe::NARROW_OOP_MODE Universe::narrow_oop_mode() {
    1009   if (narrow_oop_base() != 0) {
    1010     return HeapBasedNarrowOop;
    1011   }
    1012
    1013   if (narrow_oop_shift() != 0) {
    1014     return ZeroBasedNarrowOop;
    1015   }
    1016
    1017   return UnscaledNarrowOop;
    1018 }
    1019
    1020
    1021 void universe2_init() {
    1022   EXCEPTION_MARK;
    1023   Universe::genesis(CATCH);
    1024 }
    1025
    1026
    1027 // This function is defined in JVM.cpp
    1028 extern void initialize_converter_functions();
    1029
    1030 bool universe_post_init() {
    1031   assert(!is_init_completed(), "Error: initialization not yet completed!");
    1032   Universe::_fully_initialized = true;
    1033   EXCEPTION_MARK;
    1034   { ResourceMark rm;
    1035     Interpreter::initialize();      // needed for interpreter entry points
    1036     if (!UseSharedSpaces) {
    1037       HandleMark hm(THREAD);
    1038       KlassHandle ok_h(THREAD, SystemDictionary::Object_klass());
    1039       Universe::reinitialize_vtable_of(ok_h, CHECK_false);
    1040       Universe::reinitialize_itables(CHECK_false);
    1041     }
    1042   }
    1043
    1044   HandleMark hm(THREAD);
    1045   Klass* k;
    1046   instanceKlassHandle k_h;
    1047     // Setup preallocated empty java.lang.Class array
    1048     Universe::_the_empty_class_klass_array = oopFactory::new_objArray(SystemDictionary::Class_klass(), 0, CHECK_false);
    1049
    1050     // Setup preallocated OutOfMemoryError errors
    1051     k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_OutOfMemoryError(), true, CHECK_false);
    1052     k_h = instanceKlassHandle(THREAD, k);
    1053     Universe::_out_of_memory_error_java_heap = k_h->allocate_instance(CHECK_false);
    1054     Universe::_out_of_memory_error_metaspace = k_h->allocate_instance(CHECK_false);
    1055     Universe::_out_of_memory_error_class_metaspace = k_h->allocate_instance(CHECK_false);
    1056     Universe::_out_of_memory_error_array_size = k_h->allocate_instance(CHECK_false);
    1057     Universe::_out_of_memory_error_gc_overhead_limit =
    1058       k_h->allocate_instance(CHECK_false);
    1059     Universe::_out_of_memory_error_realloc_objects = k_h->allocate_instance(CHECK_false);
    1060
    1061     // Setup preallocated NullPointerException
    1062     // (this is currently used for a cheap & dirty solution in compiler exception handling)
    1063     k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_NullPointerException(), true, CHECK_false);
    1064     Universe::_null_ptr_exception_instance = InstanceKlass::cast(k)->allocate_instance(CHECK_false);
    1065     // Setup preallocated ArithmeticException
    1066     // (this is currently used for a cheap & dirty solution in compiler exception handling)
    1067     k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ArithmeticException(), true, CHECK_false);
    1068     Universe::_arithmetic_exception_instance = InstanceKlass::cast(k)->allocate_instance(CHECK_false);
    1069     // Virtual Machine Error for when we get into a situation we can't resolve
    1070     k = SystemDictionary::resolve_or_fail(
    1071       vmSymbols::java_lang_VirtualMachineError(), true, CHECK_false);
    1072     bool linked = InstanceKlass::cast(k)->link_class_or_fail(CHECK_false);
    1073     if (!linked) {
    1074       tty->print_cr("Unable to link/verify VirtualMachineError class");
    1075       return false; // initialization failed
    1076     }
    1077     Universe::_virtual_machine_error_instance =
    1078       InstanceKlass::cast(k)->allocate_instance(CHECK_false);
    1079
    1080     Universe::_vm_exception = InstanceKlass::cast(k)->allocate_instance(CHECK_false);
    1081
    1082   if (!DumpSharedSpaces) {
    1083     // These are the only Java fields that are currently set during shared space dumping.
    1084     // We prefer to not handle this generally, so we always reinitialize these detail messages.
    1085     Handle msg = java_lang_String::create_from_str("Java heap space", CHECK_false);
    1086     java_lang_Throwable::set_message(Universe::_out_of_memory_error_java_heap, msg());
    1087
    1088     msg = java_lang_String::create_from_str("Metaspace", CHECK_false);
    1089     java_lang_Throwable::set_message(Universe::_out_of_memory_error_metaspace, msg());
    1090     msg = java_lang_String::create_from_str("Compressed class space", CHECK_false);
    1091     java_lang_Throwable::set_message(Universe::_out_of_memory_error_class_metaspace, msg());
    1092
    1093     msg = java_lang_String::create_from_str("Requested array size exceeds VM limit", CHECK_false);
    1094     java_lang_Throwable::set_message(Universe::_out_of_memory_error_array_size, msg());
    1095
    1096     msg = java_lang_String::create_from_str("GC overhead limit exceeded", CHECK_false);
    1097     java_lang_Throwable::set_message(Universe::_out_of_memory_error_gc_overhead_limit, msg());
    1098
    1099     msg = java_lang_String::create_from_str("Java heap space: failed reallocation of scalar replaced objects", CHECK_false);
    1100     java_lang_Throwable::set_message(Universe::_out_of_memory_error_realloc_objects, msg());
    1101
    1102     msg = java_lang_String::create_from_str("/ by zero", CHECK_false);
    1103     java_lang_Throwable::set_message(Universe::_arithmetic_exception_instance, msg());
    1104
    1105     // Setup the array of errors that have preallocated backtrace
    1106     k = Universe::_out_of_memory_error_java_heap->klass();
    1107     assert(k->name() == vmSymbols::java_lang_OutOfMemoryError(), "should be out of memory error");
    1108     k_h = instanceKlassHandle(THREAD, k);
    1109
    1110     int len = (StackTraceInThrowable) ? (int)PreallocatedOutOfMemoryErrorCount : 0;
    1111     Universe::_preallocated_out_of_memory_error_array = oopFactory::new_objArray(k_h(), len, CHECK_false);
    1112     for (int i=0; i<len; i++) {
    1113       oop err = k_h->allocate_instance(CHECK_false);
    1114       Handle err_h = Handle(THREAD, err);
    1115       java_lang_Throwable::allocate_backtrace(err_h, CHECK_false);
    1116       Universe::preallocated_out_of_memory_errors()->obj_at_put(i, err_h());
    1117     }
    1118     Universe::_preallocated_out_of_memory_error_avail_count = (jint)len;
    1119   }
    1120
    1121
    1122   // Setup static method for registering finalizers
    1123   // The finalizer klass must be linked before looking up the method, in
    1124   // case it needs to get rewritten.
    1125   InstanceKlass::cast(SystemDictionary::Finalizer_klass())->link_class(CHECK_false);
    1126   Method* m = InstanceKlass::cast(SystemDictionary::Finalizer_klass())->find_method(
    1127                                   vmSymbols::register_method_name(),
    1128                                   vmSymbols::register_method_signature());
    1129   if (m == NULL || !m->is_static()) {
    1130     tty->print_cr("Unable to link/verify Finalizer.register method");
    1131     return false; // initialization failed (cannot throw exception yet)
    1132   }
    1133   Universe::_finalizer_register_cache->init(
    1134     SystemDictionary::Finalizer_klass(), m);
    1135
    1136   InstanceKlass::cast(SystemDictionary::misc_Unsafe_klass())->link_class(CHECK_false);
    1137   m = InstanceKlass::cast(SystemDictionary::misc_Unsafe_klass())->find_method(
    1138                                   vmSymbols::throwIllegalAccessError_name(),
    1139                                   vmSymbols::void_method_signature());
    1140   if (m != NULL && !m->is_static()) {
    1141     // Note null is okay; this method is used in itables, and if it is null,
    1142     // then AbstractMethodError is thrown instead.
    1143     tty->print_cr("Unable to link/verify Unsafe.throwIllegalAccessError method");
    1144     return false; // initialization failed (cannot throw exception yet)
    1145   }
    1146   Universe::_throw_illegal_access_error = m;
    1147
    1148   // Setup method for registering loaded classes in class loader vector
    1149   InstanceKlass::cast(SystemDictionary::ClassLoader_klass())->link_class(CHECK_false);
    1150   m = InstanceKlass::cast(SystemDictionary::ClassLoader_klass())->find_method(vmSymbols::addClass_name(), vmSymbols::class_void_signature());
    1151   if (m == NULL || m->is_static()) {
    1152     tty->print_cr("Unable to link/verify ClassLoader.addClass method");
    1153     return false; // initialization failed (cannot throw exception yet)
    1154   }
    1155   Universe::_loader_addClass_cache->init(
    1156     SystemDictionary::ClassLoader_klass(), m);
    1157
    1158   // Setup method for checking protection domain
    1159   InstanceKlass::cast(SystemDictionary::ProtectionDomain_klass())->link_class(CHECK_false);
    1160   m = InstanceKlass::cast(SystemDictionary::ProtectionDomain_klass())->
    1161             find_method(vmSymbols::impliesCreateAccessControlContext_name(),
    1162                         vmSymbols::void_boolean_signature());
    1163   // Allow NULL which should only happen with bootstrapping.
    1164   if (m != NULL) {
    1165     if (m->is_static()) {
    1166       // NoSuchMethodException doesn't actually work because it tries to run the
    1167       // <init> function before java_lang_Class is linked. Print error and exit.
    1168       tty->print_cr("ProtectionDomain.impliesCreateAccessControlContext() has the wrong linkage");
    1169       return false; // initialization failed
    1170     }
    1171     Universe::_pd_implies_cache->init(
    1172       SystemDictionary::ProtectionDomain_klass(), m);;
    1173   }
    1174
    1175   // The folowing is initializing converter functions for serialization in
    1176   // JVM.cpp. If we clean up the StrictMath code above we may want to find
    1177   // a better solution for this as well.
    1178   initialize_converter_functions();
    1179
    1180   // This needs to be done before the first scavenge/gc, since
    1181   // it's an input to soft ref clearing policy.
    1182   {
    1183     MutexLocker x(Heap_lock);
    1184     Universe::update_heap_info_at_gc();
    1185   }
    1186
    1187   // ("weak") refs processing infrastructure initialization
    1188   Universe::heap()->post_initialize();
    1189
    1190   // Initialize performance counters for metaspaces
    1191   MetaspaceCounters::initialize_performance_counters();
    1192   CompressedClassSpaceCounters::initialize_performance_counters();
    1193
    1194   MemoryService::add_metaspace_memory_pools();
    1195
    1196   MemoryService::set_universe_heap(Universe::_collectedHeap);
    1197 #if INCLUDE_CDS
    1198   if (UseSharedSpaces) {
    1199     SharedClassUtil::initialize(CHECK_false);
    1200   }
    1201 #endif
    1202   return true;
    1203 }
    1204
    1205
    1206 void Universe::compute_base_vtable_size() {
    1207   _base_vtable_size = ClassLoader::compute_Object_vtable();
    1208 }
    1209
    1210
    1211 // %%% The Universe::flush_foo methods belong in CodeCache.
    1212
    1213 // Flushes compiled methods dependent on dependee.
    1214 void Universe::flush_dependents_on(instanceKlassHandle dependee) {
    1215   assert_lock_strong(Compile_lock);
    1216
    1217   if (CodeCache::number_of_nmethods_with_dependencies() == 0) return;
    1218
    1219   // CodeCache can only be updated by a thread_in_VM and they will all be
    1220   // stopped dring the safepoint so CodeCache will be safe to update without
    1221   // holding the CodeCache_lock.
    1222
    1223   KlassDepChange changes(dependee);
    1224
    1225   // Compute the dependent nmethods
    1226   if (CodeCache::mark_for_deoptimization(changes) > 0) {
    1227     // At least one nmethod has been marked for deoptimization
    1228     VM_Deoptimize op;
    1229     VMThread::execute(&op);
    1230   }
    1231 }
    1232
    1233 // Flushes compiled methods dependent on a particular CallSite
    1234 // instance when its target is different than the given MethodHandle.
    1235 void Universe::flush_dependents_on(Handle call_site, Handle method_handle) {
    1236   assert_lock_strong(Compile_lock);
    1237
    1238   if (CodeCache::number_of_nmethods_with_dependencies() == 0) return;
    1239
    1240   // CodeCache can only be updated by a thread_in_VM and they will all be
    1241   // stopped dring the safepoint so CodeCache will be safe to update without
    1242   // holding the CodeCache_lock.
    1243
    1244   CallSiteDepChange changes(call_site(), method_handle());
    1245
    1246   // Compute the dependent nmethods that have a reference to a
    1247   // CallSite object.  We use InstanceKlass::mark_dependent_nmethod
    1248   // directly instead of CodeCache::mark_for_deoptimization because we
    1249   // want dependents on the call site class only not all classes in
    1250   // the ContextStream.
    1251   int marked = 0;
    1252   {
    1253     MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
    1254     InstanceKlass* call_site_klass = InstanceKlass::cast(call_site->klass());
    1255     marked = call_site_klass->mark_dependent_nmethods(changes);
    1256   }
    1257   if (marked > 0) {
    1258     // At least one nmethod has been marked for deoptimization
    1259     VM_Deoptimize op;
    1260     VMThread::execute(&op);
    1261   }
    1262 }
    1263
    1264 #ifdef HOTSWAP
    1265 // Flushes compiled methods dependent on dependee in the evolutionary sense
    1266 void Universe::flush_evol_dependents_on(instanceKlassHandle ev_k_h) {
    1267   // --- Compile_lock is not held. However we are at a safepoint.
    1268   assert_locked_or_safepoint(Compile_lock);
    1269   if (CodeCache::number_of_nmethods_with_dependencies() == 0) return;
    1270
    1271   // CodeCache can only be updated by a thread_in_VM and they will all be
    1272   // stopped dring the safepoint so CodeCache will be safe to update without
    1273   // holding the CodeCache_lock.
    1274
    1275   // Compute the dependent nmethods
    1276   if (CodeCache::mark_for_evol_deoptimization(ev_k_h) > 0) {
    1277     // At least one nmethod has been marked for deoptimization
    1278
    1279     // All this already happens inside a VM_Operation, so we'll do all the work here.
    1280     // Stuff copied from VM_Deoptimize and modified slightly.
    1281
    1282     // We do not want any GCs to happen while we are in the middle of this VM operation
    1283     ResourceMark rm;
    1284     DeoptimizationMarker dm;
    1285
    1286     // Deoptimize all activations depending on marked nmethods
    1287     Deoptimization::deoptimize_dependents();
    1288
    1289     // Make the dependent methods not entrant (in VM_Deoptimize they are made zombies)
    1290     CodeCache::make_marked_nmethods_not_entrant();
    1291   }
    1292 }
    1293 #endif // HOTSWAP
    1294
    1295
    1296 // Flushes compiled methods dependent on dependee
    1297 void Universe::flush_dependents_on_method(methodHandle m_h) {
    1298   // --- Compile_lock is not held. However we are at a safepoint.
    1299   assert_locked_or_safepoint(Compile_lock);
    1300
    1301   // CodeCache can only be updated by a thread_in_VM and they will all be
    1302   // stopped dring the safepoint so CodeCache will be safe to update without
    1303   // holding the CodeCache_lock.
    1304
    1305   // Compute the dependent nmethods
    1306   if (CodeCache::mark_for_deoptimization(m_h()) > 0) {
    1307     // At least one nmethod has been marked for deoptimization
    1308
    1309     // All this already happens inside a VM_Operation, so we'll do all the work here.
    1310     // Stuff copied from VM_Deoptimize and modified slightly.
    1311
    1312     // We do not want any GCs to happen while we are in the middle of this VM operation
    1313     ResourceMark rm;
    1314     DeoptimizationMarker dm;
    1315
    1316     // Deoptimize all activations depending on marked nmethods
    1317     Deoptimization::deoptimize_dependents();
    1318
    1319     // Make the dependent methods not entrant (in VM_Deoptimize they are made zombies)
    1320     CodeCache::make_marked_nmethods_not_entrant();
    1321   }
    1322 }
    1323
    1324 void Universe::print() {
    1325   print_on(gclog_or_tty);
    1326 }
    1327
    1328 void Universe::print_on(outputStream* st, bool extended) {
    1329   st->print_cr("Heap");
    1330   if (!extended) {
    1331     heap()->print_on(st);
    1332   } else {
    1333     heap()->print_extended_on(st);
    1334   }
    1335 }
    1336
    1337 void Universe::print_heap_at_SIGBREAK() {
    1338   if (PrintHeapAtSIGBREAK) {
    1339     MutexLocker hl(Heap_lock);
    1340     print_on(tty);
    1341     tty->cr();
    1342     tty->flush();
    1343   }
    1344 }
    1345
    1346 void Universe::print_heap_before_gc(outputStream* st, bool ignore_extended) {
    1347   st->print_cr("{Heap before GC invocations=%u (full %u):",
    1348                heap()->total_collections(),
    1349                heap()->total_full_collections());
    1350   if (!PrintHeapAtGCExtended || ignore_extended) {
    1351     heap()->print_on(st);
    1352   } else {
    1353     heap()->print_extended_on(st);
    1354   }
    1355 }
    1356
    1357 void Universe::print_heap_after_gc(outputStream* st, bool ignore_extended) {
    1358   st->print_cr("Heap after GC invocations=%u (full %u):",
    1359                heap()->total_collections(),
    1360                heap()->total_full_collections());
    1361   if (!PrintHeapAtGCExtended || ignore_extended) {
    1362     heap()->print_on(st);
    1363   } else {
    1364     heap()->print_extended_on(st);
    1365   }
    1366   st->print_cr("}");
    1367 }
    1368
    1369 void Universe::verify(VerifyOption option, const char* prefix, bool silent) {
    1370   // The use of _verify_in_progress is a temporary work around for
    1371   // 6320749.  Don't bother with a creating a class to set and clear
    1372   // it since it is only used in this method and the control flow is
    1373   // straight forward.
    1374   _verify_in_progress = true;
    1375
    1376   COMPILER2_PRESENT(
    1377     assert(!DerivedPointerTable::is_active(),
    1378          "DPT should not be active during verification "
    1379          "(of thread stacks below)");
    1380   )
    1381
    1382   ResourceMark rm;
    1383   HandleMark hm;  // Handles created during verification can be zapped
    1384   _verify_count++;
    1385
    1386   if (!silent) gclog_or_tty->print("%s", prefix);
    1387   if (!silent) gclog_or_tty->print("[Verifying ");
    1388   if (!silent) gclog_or_tty->print("threads ");
    1389   Threads::verify();
    1390   if (!silent) gclog_or_tty->print("heap ");
    1391   heap()->verify(silent, option);
    1392   if (!silent) gclog_or_tty->print("syms ");
    1393   SymbolTable::verify();
    1394   if (!silent) gclog_or_tty->print("strs ");
    1395   StringTable::verify();
    1396   {
    1397     MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
    1398     if (!silent) gclog_or_tty->print("zone ");
    1399     CodeCache::verify();
    1400   }
    1401   if (!silent) gclog_or_tty->print("dict ");
    1402   SystemDictionary::verify();
    1403 #ifndef PRODUCT
    1404   if (!silent) gclog_or_tty->print("cldg ");
    1405   ClassLoaderDataGraph::verify();
    1406 #endif
    1407   if (!silent) gclog_or_tty->print("metaspace chunks ");
    1408   MetaspaceAux::verify_free_chunks();
    1409   if (!silent) gclog_or_tty->print("hand ");
    1410   JNIHandles::verify();
    1411   if (!silent) gclog_or_tty->print("C-heap ");
    1412   os::check_heap();
    1413   if (!silent) gclog_or_tty->print("code cache ");
    1414   CodeCache::verify_oops();
    1415   if (!silent) gclog_or_tty->print_cr("]");
    1416
    1417   _verify_in_progress = false;
    1418 }
    1419
    1420 // Oop verification (see MacroAssembler::verify_oop)
    1421
    1422 static uintptr_t _verify_oop_data[2]   = {0, (uintptr_t)-1};
    1423 static uintptr_t _verify_klass_data[2] = {0, (uintptr_t)-1};
    1424
    1425
    1426 #ifndef PRODUCT
    1427
    1428 static void calculate_verify_data(uintptr_t verify_data[2],
    1429                                   HeapWord* low_boundary,
    1430                                   HeapWord* high_boundary) {
    1431   assert(low_boundary < high_boundary, "bad interval");
    1432
    1433   // decide which low-order bits we require to be clear:
    1434   size_t alignSize = MinObjAlignmentInBytes;
    1435   size_t min_object_size = CollectedHeap::min_fill_size();
    1436
    1437   // make an inclusive limit:
    1438   uintptr_t max = (uintptr_t)high_boundary - min_object_size*wordSize;
    1439   uintptr_t min = (uintptr_t)low_boundary;
    1440   assert(min < max, "bad interval");
    1441   uintptr_t diff = max ^ min;
    1442
    1443   // throw away enough low-order bits to make the diff vanish
    1444   uintptr_t mask = (uintptr_t)(-1);
    1445   while ((mask & diff) != 0)
    1446     mask <<= 1;
    1447   uintptr_t bits = (min & mask);
    1448   assert(bits == (max & mask), "correct mask");
    1449   // check an intermediate value between min and max, just to make sure:
    1450   assert(bits == ((min + (max-min)/2) & mask), "correct mask");
    1451
    1452   // require address alignment, too:
    1453   mask |= (alignSize - 1);
    1454
    1455   if (!(verify_data[0] == 0 && verify_data[1] == (uintptr_t)-1)) {
    1456     assert(verify_data[0] == mask && verify_data[1] == bits, "mask stability");
    1457   }
    1458   verify_data[0] = mask;
    1459   verify_data[1] = bits;
    1460 }
    1461
    1462 // Oop verification (see MacroAssembler::verify_oop)
    1463
    1464 uintptr_t Universe::verify_oop_mask() {
    1465   MemRegion m = heap()->reserved_region();
    1466   calculate_verify_data(_verify_oop_data,
    1467                         m.start(),
    1468                         m.end());
    1469   return _verify_oop_data[0];
    1470 }
    1471
    1472
    1473
    1474 uintptr_t Universe::verify_oop_bits() {
    1475   verify_oop_mask();
    1476   return _verify_oop_data[1];
    1477 }
    1478
    1479 uintptr_t Universe::verify_mark_mask() {
    1480   return markOopDesc::lock_mask_in_place;
    1481 }
    1482
    1483 uintptr_t Universe::verify_mark_bits() {
    1484   intptr_t mask = verify_mark_mask();
    1485   intptr_t bits = (intptr_t)markOopDesc::prototype();
    1486   assert((bits & ~mask) == 0, "no stray header bits");
    1487   return bits;
    1488 }
    1489 #endif // PRODUCT
    1490
    1491
    1492 void Universe::compute_verify_oop_data() {
    1493   verify_oop_mask();
    1494   verify_oop_bits();
    1495   verify_mark_mask();
    1496   verify_mark_bits();
    1497 }
    1498
    1499
    1500 void LatestMethodCache::init(Klass* k, Method* m) {
    1501   if (!UseSharedSpaces) {
    1502     _klass = k;
    1503   }
    1504 #ifndef PRODUCT
    1505   else {
    1506     // sharing initilization should have already set up _klass
    1507     assert(_klass != NULL, "just checking");
    1508   }
    1509 #endif
    1510
    1511   _method_idnum = m->method_idnum();
    1512   assert(_method_idnum >= 0, "sanity check");
    1513 }
    1514
    1515
    1516 Method* LatestMethodCache::get_method() {
    1517   if (klass() == NULL) return NULL;
    1518   InstanceKlass* ik = InstanceKlass::cast(klass());
    1519   Method* m = ik->method_with_idnum(method_idnum());
    1520   assert(m != NULL, "sanity check");
    1521   return m;
    1522 }
    1523
    1524
    1525 #ifdef ASSERT
    1526 // Release dummy object(s) at bottom of heap
    1527 bool Universe::release_fullgc_alot_dummy() {
    1528   MutexLocker ml(FullGCALot_lock);
    1529   if (_fullgc_alot_dummy_array != NULL) {
    1530     if (_fullgc_alot_dummy_next >= _fullgc_alot_dummy_array->length()) {
    1531       // No more dummies to release, release entire array instead
    1532       _fullgc_alot_dummy_array = NULL;
    1533       return false;
    1534     }
    1535     if (!UseConcMarkSweepGC) {
    1536       // Release dummy at bottom of old generation
    1537       _fullgc_alot_dummy_array->obj_at_put(_fullgc_alot_dummy_next++, NULL);
    1538     }
    1539     // Release dummy at bottom of permanent generation
    1540     _fullgc_alot_dummy_array->obj_at_put(_fullgc_alot_dummy_next++, NULL);
    1541   }
    1542   return true;
    1543 }
    1544
    1545 #endif // ASSERT
    --- EOF ---