1 /* 2 * Copyright (c) 1997, 2017, 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 #ifndef SHARE_VM_MEMORY_UNIVERSE_HPP 26 #define SHARE_VM_MEMORY_UNIVERSE_HPP 27 28 #include "oops/array.hpp" 29 #include "runtime/handles.hpp" 30 #include "utilities/growableArray.hpp" 31 32 // Universe is a name space holding known system classes and objects in the VM. 33 // 34 // Loaded classes are accessible through the SystemDictionary. 35 // 36 // The object heap is allocated and accessed through Universe, and various allocation 37 // support is provided. Allocation by the interpreter and compiled code is done inline 38 // and bails out to Scavenge::invoke_and_allocate. 39 40 class CollectedHeap; 41 class DeferredObjAllocEvent; 42 43 44 // A helper class for caching a Method* when the user of the cache 45 // only cares about the latest version of the Method*. This cache safely 46 // interacts with the RedefineClasses API. 47 48 class LatestMethodCache : public CHeapObj<mtClass> { 49 // We save the Klass* and the idnum of Method* in order to get 50 // the current cached Method*. 51 private: 52 Klass* _klass; 53 int _method_idnum; 54 55 public: 56 LatestMethodCache() { _klass = NULL; _method_idnum = -1; } 57 ~LatestMethodCache() { _klass = NULL; _method_idnum = -1; } 58 59 void init(Klass* k, Method* m); 60 Klass* klass() const { return _klass; } 61 int method_idnum() const { return _method_idnum; } 62 63 Method* get_method(); 64 65 // CDS support. Replace the klass in this with the archive version 66 // could use this for Enhanced Class Redefinition also. 67 void serialize(SerializeClosure* f) { 68 f->do_ptr((void**)&_klass); 69 } 70 void metaspace_pointers_do(MetaspaceClosure* it); 71 }; 72 73 74 // For UseCompressedOops. 75 struct NarrowPtrStruct { 76 // Base address for oop-within-java-object materialization. 77 // NULL if using wide oops or zero based narrow oops. 78 address _base; 79 // Number of shift bits for encoding/decoding narrow ptrs. 80 // 0 if using wide ptrs or zero based unscaled narrow ptrs, 81 // LogMinObjAlignmentInBytes/LogKlassAlignmentInBytes otherwise. 82 int _shift; 83 // Generate code with implicit null checks for narrow ptrs. 84 bool _use_implicit_null_checks; 85 }; 86 87 enum VerifyOption { 88 VerifyOption_Default = 0, 89 90 // G1 91 VerifyOption_G1UsePrevMarking = VerifyOption_Default, 92 VerifyOption_G1UseNextMarking = VerifyOption_G1UsePrevMarking + 1, 93 VerifyOption_G1UseMarkWord = VerifyOption_G1UseNextMarking + 1 94 }; 95 96 class Universe: AllStatic { 97 // Ugh. Universe is much too friendly. 98 friend class MarkSweep; 99 friend class oopDesc; 100 friend class ClassLoader; 101 friend class SystemDictionary; 102 friend class ReservedHeapSpace; 103 friend class VMStructs; 104 friend class VM_PopulateDumpSharedSpace; 105 friend class Metaspace; 106 friend class MetaspaceShared; 107 108 friend jint universe_init(); 109 friend void universe2_init(); 110 friend bool universe_post_init(); 111 friend void universe_post_module_init(); 112 113 private: 114 // Known classes in the VM 115 static Klass* _boolArrayKlassObj; 116 static Klass* _byteArrayKlassObj; 117 static Klass* _charArrayKlassObj; 118 static Klass* _intArrayKlassObj; 119 static Klass* _shortArrayKlassObj; 120 static Klass* _longArrayKlassObj; 121 static Klass* _singleArrayKlassObj; 122 static Klass* _doubleArrayKlassObj; 123 static Klass* _typeArrayKlassObjs[T_VOID+1]; 124 125 static Klass* _objectArrayKlassObj; 126 127 // Known objects in the VM 128 129 // Primitive objects 130 static oop _int_mirror; 131 static oop _float_mirror; 132 static oop _double_mirror; 133 static oop _byte_mirror; 134 static oop _bool_mirror; 135 static oop _char_mirror; 136 static oop _long_mirror; 137 static oop _short_mirror; 138 static oop _void_mirror; 139 140 static oop _main_thread_group; // Reference to the main thread group object 141 static oop _system_thread_group; // Reference to the system thread group object 142 143 static objArrayOop _the_empty_class_klass_array; // Canonicalized obj array of type java.lang.Class 144 static oop _the_null_string; // A cache of "null" as a Java string 145 static oop _the_min_jint_string; // A cache of "-2147483648" as a Java string 146 static LatestMethodCache* _finalizer_register_cache; // static method for registering finalizable objects 147 static LatestMethodCache* _loader_addClass_cache; // method for registering loaded classes in class loader vector 148 static LatestMethodCache* _pd_implies_cache; // method for checking protection domain attributes 149 static LatestMethodCache* _throw_illegal_access_error_cache; // Unsafe.throwIllegalAccessError() method 150 static LatestMethodCache* _do_stack_walk_cache; // method for stack walker callback 151 152 // preallocated error objects (no backtrace) 153 static oop _out_of_memory_error_java_heap; 154 static oop _out_of_memory_error_metaspace; 155 static oop _out_of_memory_error_class_metaspace; 156 static oop _out_of_memory_error_array_size; 157 static oop _out_of_memory_error_gc_overhead_limit; 158 static oop _out_of_memory_error_realloc_objects; 159 160 // preallocated cause message for delayed StackOverflowError 161 static oop _delayed_stack_overflow_error_message; 162 163 static Array<int>* _the_empty_int_array; // Canonicalized int array 164 static Array<u2>* _the_empty_short_array; // Canonicalized short array 165 static Array<Klass*>* _the_empty_klass_array; // Canonicalized klass obj array 166 static Array<Method*>* _the_empty_method_array; // Canonicalized method obj array 167 168 static Array<Klass*>* _the_array_interfaces_array; 169 170 // array of preallocated error objects with backtrace 171 static objArrayOop _preallocated_out_of_memory_error_array; 172 173 // number of preallocated error objects available for use 174 static volatile jint _preallocated_out_of_memory_error_avail_count; 175 176 static oop _null_ptr_exception_instance; // preallocated exception object 177 static oop _arithmetic_exception_instance; // preallocated exception object 178 static oop _virtual_machine_error_instance; // preallocated exception object 179 // The object used as an exception dummy when exceptions are thrown for 180 // the vm thread. 181 static oop _vm_exception; 182 183 static oop _allocation_context_notification_obj; 184 185 // References waiting to be transferred to the ReferenceHandler 186 static oop _reference_pending_list; 187 188 // The particular choice of collected heap. 189 static CollectedHeap* _collectedHeap; 190 191 static intptr_t _non_oop_bits; 192 193 // For UseCompressedOops. 194 static struct NarrowPtrStruct _narrow_oop; 195 // For UseCompressedClassPointers. 196 static struct NarrowPtrStruct _narrow_klass; 197 static address _narrow_ptrs_base; 198 199 // array of dummy objects used with +FullGCAlot 200 debug_only(static objArrayOop _fullgc_alot_dummy_array;) 201 // index of next entry to clear 202 debug_only(static int _fullgc_alot_dummy_next;) 203 204 // Compiler/dispatch support 205 static int _base_vtable_size; // Java vtbl size of klass Object (in words) 206 207 // Initialization 208 static bool _bootstrapping; // true during genesis 209 static bool _module_initialized; // true after call_initPhase2 called 210 static bool _fully_initialized; // true after universe_init and initialize_vtables called 211 212 // the array of preallocated errors with backtraces 213 static objArrayOop preallocated_out_of_memory_errors() { return _preallocated_out_of_memory_error_array; } 214 215 // generate an out of memory error; if possible using an error with preallocated backtrace; 216 // otherwise return the given default error. 217 static oop gen_out_of_memory_error(oop default_err); 218 219 // Historic gc information 220 static size_t _heap_capacity_at_last_gc; 221 static size_t _heap_used_at_last_gc; 222 223 template <class Heap, class Policy> static CollectedHeap* create_heap_with_policy(); 224 static CollectedHeap* create_heap(); 225 static CollectedHeap* create_heap_ext(); 226 static jint initialize_heap(); 227 static void initialize_basic_type_mirrors(TRAPS); 228 static void fixup_mirrors(TRAPS); 229 230 static void reinitialize_vtable_of(Klass* k, TRAPS); 231 static void reinitialize_itables(TRAPS); 232 static void compute_base_vtable_size(); // compute vtable size of class Object 233 234 static void genesis(TRAPS); // Create the initial world 235 236 // Mirrors for primitive classes (created eagerly) 237 static oop check_mirror(oop m) { 238 assert(m != NULL, "mirror not initialized"); 239 return m; 240 } 241 242 static void set_narrow_oop_base(address base) { 243 assert(UseCompressedOops, "no compressed oops?"); 244 _narrow_oop._base = base; 245 } 246 static void set_narrow_klass_base(address base) { 247 assert(UseCompressedClassPointers, "no compressed klass ptrs?"); 248 _narrow_klass._base = base; 249 } 250 static void set_narrow_oop_use_implicit_null_checks(bool use) { 251 assert(UseCompressedOops, "no compressed ptrs?"); 252 _narrow_oop._use_implicit_null_checks = use; 253 } 254 255 // Debugging 256 static int _verify_count; // number of verifies done 257 258 // True during call to verify(). Should only be set/cleared in verify(). 259 static bool _verify_in_progress; 260 static long verify_flags; 261 262 static uintptr_t _verify_oop_mask; 263 static uintptr_t _verify_oop_bits; 264 265 static void calculate_verify_data(HeapWord* low_boundary, HeapWord* high_boundary) PRODUCT_RETURN; 266 static void compute_verify_oop_data(); 267 268 public: 269 // Known classes in the VM 270 static Klass* boolArrayKlassObj() { return _boolArrayKlassObj; } 271 static Klass* byteArrayKlassObj() { return _byteArrayKlassObj; } 272 static Klass* charArrayKlassObj() { return _charArrayKlassObj; } 273 static Klass* intArrayKlassObj() { return _intArrayKlassObj; } 274 static Klass* shortArrayKlassObj() { return _shortArrayKlassObj; } 275 static Klass* longArrayKlassObj() { return _longArrayKlassObj; } 276 static Klass* singleArrayKlassObj() { return _singleArrayKlassObj; } 277 static Klass* doubleArrayKlassObj() { return _doubleArrayKlassObj; } 278 279 static Klass* objectArrayKlassObj() { 280 return _objectArrayKlassObj; 281 } 282 283 static Klass* typeArrayKlassObj(BasicType t) { 284 assert((uint)t < T_VOID+1, "range check for type: %s", type2name(t)); 285 assert(_typeArrayKlassObjs[t] != NULL, "domain check"); 286 return _typeArrayKlassObjs[t]; 287 } 288 289 // Known objects in the VM 290 static oop int_mirror() { return check_mirror(_int_mirror); } 291 static oop float_mirror() { return check_mirror(_float_mirror); } 292 static oop double_mirror() { return check_mirror(_double_mirror); } 293 static oop byte_mirror() { return check_mirror(_byte_mirror); } 294 static oop bool_mirror() { return check_mirror(_bool_mirror); } 295 static oop char_mirror() { return check_mirror(_char_mirror); } 296 static oop long_mirror() { return check_mirror(_long_mirror); } 297 static oop short_mirror() { return check_mirror(_short_mirror); } 298 static oop void_mirror() { return check_mirror(_void_mirror); } 299 300 // table of same 301 static oop _mirrors[T_VOID+1]; 302 303 static oop java_mirror(BasicType t) { 304 assert((uint)t < T_VOID+1, "range check"); 305 return check_mirror(_mirrors[t]); 306 } 307 static oop main_thread_group() { return _main_thread_group; } 308 static void set_main_thread_group(oop group) { _main_thread_group = group;} 309 310 static oop system_thread_group() { return _system_thread_group; } 311 static void set_system_thread_group(oop group) { _system_thread_group = group;} 312 313 static objArrayOop the_empty_class_klass_array () { return _the_empty_class_klass_array; } 314 static Array<Klass*>* the_array_interfaces_array() { return _the_array_interfaces_array; } 315 static oop the_null_string() { return _the_null_string; } 316 static oop the_min_jint_string() { return _the_min_jint_string; } 317 318 static Method* finalizer_register_method() { return _finalizer_register_cache->get_method(); } 319 static Method* loader_addClass_method() { return _loader_addClass_cache->get_method(); } 320 321 static Method* protection_domain_implies_method() { return _pd_implies_cache->get_method(); } 322 static Method* throw_illegal_access_error() { return _throw_illegal_access_error_cache->get_method(); } 323 324 static Method* do_stack_walk_method() { return _do_stack_walk_cache->get_method(); } 325 326 // Function to initialize these 327 static void initialize_known_methods(TRAPS); 328 329 static oop null_ptr_exception_instance() { return _null_ptr_exception_instance; } 330 static oop arithmetic_exception_instance() { return _arithmetic_exception_instance; } 331 static oop virtual_machine_error_instance() { return _virtual_machine_error_instance; } 332 static oop vm_exception() { return _vm_exception; } 333 334 static inline oop allocation_context_notification_obj(); 335 static inline void set_allocation_context_notification_obj(oop obj); 336 337 // Reference pending list manipulation. Access is protected by 338 // Heap_lock. The getter, setter and predicate require the caller 339 // owns the lock. Swap is used by parallel non-concurrent reference 340 // processing threads, where some higher level controller owns 341 // Heap_lock, so requires the lock is locked, but not necessarily by 342 // the current thread. 343 static oop reference_pending_list(); 344 static void set_reference_pending_list(oop list); 345 static bool has_reference_pending_list(); 346 static oop swap_reference_pending_list(oop list); 347 348 static Array<int>* the_empty_int_array() { return _the_empty_int_array; } 349 static Array<u2>* the_empty_short_array() { return _the_empty_short_array; } 350 static Array<Method*>* the_empty_method_array() { return _the_empty_method_array; } 351 static Array<Klass*>* the_empty_klass_array() { return _the_empty_klass_array; } 352 353 // OutOfMemoryError support. Returns an error with the required message. The returned error 354 // may or may not have a backtrace. If error has a backtrace then the stack trace is already 355 // filled in. 356 static oop out_of_memory_error_java_heap() { return gen_out_of_memory_error(_out_of_memory_error_java_heap); } 357 static oop out_of_memory_error_metaspace() { return gen_out_of_memory_error(_out_of_memory_error_metaspace); } 358 static oop out_of_memory_error_class_metaspace() { return gen_out_of_memory_error(_out_of_memory_error_class_metaspace); } 359 static oop out_of_memory_error_array_size() { return gen_out_of_memory_error(_out_of_memory_error_array_size); } 360 static oop out_of_memory_error_gc_overhead_limit() { return gen_out_of_memory_error(_out_of_memory_error_gc_overhead_limit); } 361 static oop out_of_memory_error_realloc_objects() { return gen_out_of_memory_error(_out_of_memory_error_realloc_objects); } 362 static oop delayed_stack_overflow_error_message() { return _delayed_stack_overflow_error_message; } 363 364 // Accessors needed for fast allocation 365 static Klass** boolArrayKlassObj_addr() { return &_boolArrayKlassObj; } 366 static Klass** byteArrayKlassObj_addr() { return &_byteArrayKlassObj; } 367 static Klass** charArrayKlassObj_addr() { return &_charArrayKlassObj; } 368 static Klass** intArrayKlassObj_addr() { return &_intArrayKlassObj; } 369 static Klass** shortArrayKlassObj_addr() { return &_shortArrayKlassObj; } 370 static Klass** longArrayKlassObj_addr() { return &_longArrayKlassObj; } 371 static Klass** singleArrayKlassObj_addr() { return &_singleArrayKlassObj; } 372 static Klass** doubleArrayKlassObj_addr() { return &_doubleArrayKlassObj; } 373 static Klass** objectArrayKlassObj_addr() { return &_objectArrayKlassObj; } 374 375 // The particular choice of collected heap. 376 static CollectedHeap* heap() { return _collectedHeap; } 377 378 // For UseCompressedOops 379 // Narrow Oop encoding mode: 380 // 0 - Use 32-bits oops without encoding when 381 // NarrowOopHeapBaseMin + heap_size < 4Gb 382 // 1 - Use zero based compressed oops with encoding when 383 // NarrowOopHeapBaseMin + heap_size < 32Gb 384 // 2 - Use compressed oops with disjoint heap base if 385 // base is 32G-aligned and base > 0. This allows certain 386 // optimizations in encoding/decoding. 387 // Disjoint: Bits used in base are disjoint from bits used 388 // for oops ==> oop = (cOop << 3) | base. One can disjoint 389 // the bits of an oop into base and compressed oop. 390 // 3 - Use compressed oops with heap base + encoding. 391 enum NARROW_OOP_MODE { 392 UnscaledNarrowOop = 0, 393 ZeroBasedNarrowOop = 1, 394 DisjointBaseNarrowOop = 2, 395 HeapBasedNarrowOop = 3, 396 AnyNarrowOopMode = 4 397 }; 398 static NARROW_OOP_MODE narrow_oop_mode(); 399 static const char* narrow_oop_mode_to_string(NARROW_OOP_MODE mode); 400 static char* preferred_heap_base(size_t heap_size, size_t alignment, NARROW_OOP_MODE mode); 401 static char* preferred_metaspace_base(size_t heap_size, NARROW_OOP_MODE mode); 402 static address narrow_oop_base() { return _narrow_oop._base; } 403 // Test whether bits of addr and possible offsets into the heap overlap. 404 static bool is_disjoint_heap_base_address(address addr) { 405 return (((uint64_t)(intptr_t)addr) & 406 (((uint64_t)UCONST64(0xFFFFffffFFFFffff)) >> (32-LogMinObjAlignmentInBytes))) == 0; 407 } 408 // Check for disjoint base compressed oops. 409 static bool narrow_oop_base_disjoint() { 410 return _narrow_oop._base != NULL && is_disjoint_heap_base_address(_narrow_oop._base); 411 } 412 // Check for real heapbased compressed oops. 413 // We must subtract the base as the bits overlap. 414 // If we negate above function, we also get unscaled and zerobased. 415 static bool narrow_oop_base_overlaps() { 416 return _narrow_oop._base != NULL && !is_disjoint_heap_base_address(_narrow_oop._base); 417 } 418 static bool is_narrow_oop_base(void* addr) { return (narrow_oop_base() == (address)addr); } 419 static int narrow_oop_shift() { return _narrow_oop._shift; } 420 static bool narrow_oop_use_implicit_null_checks() { return _narrow_oop._use_implicit_null_checks; } 421 422 // For UseCompressedClassPointers 423 static address narrow_klass_base() { return _narrow_klass._base; } 424 static bool is_narrow_klass_base(void* addr) { return (narrow_klass_base() == (address)addr); } 425 static int narrow_klass_shift() { return _narrow_klass._shift; } 426 static bool narrow_klass_use_implicit_null_checks() { return _narrow_klass._use_implicit_null_checks; } 427 428 static address* narrow_ptrs_base_addr() { return &_narrow_ptrs_base; } 429 static void set_narrow_ptrs_base(address a) { _narrow_ptrs_base = a; } 430 static address narrow_ptrs_base() { return _narrow_ptrs_base; } 431 432 static void print_compressed_oops_mode(outputStream* st); 433 434 // this is set in vm_version on sparc (and then reset in universe afaict) 435 static void set_narrow_oop_shift(int shift) { 436 _narrow_oop._shift = shift; 437 } 438 439 static void set_narrow_klass_shift(int shift) { 440 assert(shift == 0 || shift == LogKlassAlignmentInBytes, "invalid shift for klass ptrs"); 441 _narrow_klass._shift = shift; 442 } 443 444 // Reserve Java heap and determine CompressedOops mode 445 static ReservedSpace reserve_heap(size_t heap_size, size_t alignment); 446 447 // Historic gc information 448 static size_t get_heap_capacity_at_last_gc() { return _heap_capacity_at_last_gc; } 449 static size_t get_heap_free_at_last_gc() { return _heap_capacity_at_last_gc - _heap_used_at_last_gc; } 450 static size_t get_heap_used_at_last_gc() { return _heap_used_at_last_gc; } 451 static void update_heap_info_at_gc(); 452 453 // Testers 454 static bool is_bootstrapping() { return _bootstrapping; } 455 static bool is_module_initialized() { return _module_initialized; } 456 static bool is_fully_initialized() { return _fully_initialized; } 457 458 static inline bool element_type_should_be_aligned(BasicType type); 459 static inline bool field_type_should_be_aligned(BasicType type); 460 static bool on_page_boundary(void* addr); 461 static bool should_fill_in_stack_trace(Handle throwable); 462 static void check_alignment(uintx size, uintx alignment, const char* name); 463 464 // Finalizer support. 465 static void run_finalizers_on_exit(); 466 467 // Iteration 468 469 // Apply "f" to the addresses of all the direct heap pointers maintained 470 // as static fields of "Universe". 471 static void oops_do(OopClosure* f, bool do_all = false); 472 473 // CDS support 474 static void serialize(SerializeClosure* f, bool do_all = false); 475 476 // Apply "f" to all klasses for basic types (classes not present in 477 // SystemDictionary). 478 static void basic_type_classes_do(void f(Klass*)); 479 static void metaspace_pointers_do(MetaspaceClosure* it); 480 481 // Debugging 482 enum VERIFY_FLAGS { 483 Verify_Threads = 1, 484 Verify_Heap = 2, 485 Verify_SymbolTable = 4, 486 Verify_StringTable = 8, 487 Verify_CodeCache = 16, 488 Verify_SystemDictionary = 32, 489 Verify_ClassLoaderDataGraph = 64, 490 Verify_MetaspaceAux = 128, 491 Verify_JNIHandles = 256, 492 Verify_CodeCacheOops = 512, 493 Verify_All = -1 494 }; 495 static void initialize_verify_flags(); 496 static bool should_verify_subset(uint subset); 497 static bool verify_in_progress() { return _verify_in_progress; } 498 static void verify(VerifyOption option, const char* prefix); 499 static void verify(const char* prefix) { 500 verify(VerifyOption_Default, prefix); 501 } 502 static void verify() { 503 verify(""); 504 } 505 506 static int verify_count() { return _verify_count; } 507 static void print_on(outputStream* st); 508 static void print_heap_at_SIGBREAK(); 509 static void print_heap_before_gc(); 510 static void print_heap_after_gc(); 511 512 // Change the number of dummy objects kept reachable by the full gc dummy 513 // array; this should trigger relocation in a sliding compaction collector. 514 debug_only(static bool release_fullgc_alot_dummy();) 515 // The non-oop pattern (see compiledIC.hpp, etc) 516 static void* non_oop_word(); 517 518 // Oop verification (see MacroAssembler::verify_oop) 519 static uintptr_t verify_oop_mask() PRODUCT_RETURN0; 520 static uintptr_t verify_oop_bits() PRODUCT_RETURN0; 521 static uintptr_t verify_mark_bits() PRODUCT_RETURN0; 522 static uintptr_t verify_mark_mask() PRODUCT_RETURN0; 523 524 // Compiler support 525 static int base_vtable_size() { return _base_vtable_size; } 526 }; 527 528 class DeferredObjAllocEvent : public CHeapObj<mtInternal> { 529 private: 530 oop _oop; 531 size_t _bytesize; 532 jint _arena_id; 533 534 public: 535 DeferredObjAllocEvent(const oop o, const size_t s, const jint id) { 536 _oop = o; 537 _bytesize = s; 538 _arena_id = id; 539 } 540 541 ~DeferredObjAllocEvent() { 542 } 543 544 jint arena_id() { return _arena_id; } 545 size_t bytesize() { return _bytesize; } 546 oop get_oop() { return _oop; } 547 }; 548 549 #endif // SHARE_VM_MEMORY_UNIVERSE_HPP