1 /* 2 * Copyright (c) 1997, 2018, 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_OOPS_KLASS_HPP 26 #define SHARE_VM_OOPS_KLASS_HPP 27 28 #include "classfile/classLoaderData.hpp" 29 #include "memory/iterator.hpp" 30 #include "memory/memRegion.hpp" 31 #include "oops/metadata.hpp" 32 #include "oops/oop.hpp" 33 #include "oops/oopHandle.hpp" 34 #include "utilities/accessFlags.hpp" 35 #include "utilities/macros.hpp" 36 #if INCLUDE_JFR 37 #include "jfr/support/jfrTraceIdExtension.hpp" 38 #endif 39 40 // Klass IDs for all subclasses of Klass 41 enum KlassID { 42 InstanceKlassID, 43 InstanceRefKlassID, 44 InstanceMirrorKlassID, 45 InstanceClassLoaderKlassID, 46 TypeArrayKlassID, 47 ObjArrayKlassID 48 }; 49 50 const uint KLASS_ID_COUNT = 6; 51 52 // 53 // A Klass provides: 54 // 1: language level class object (method dictionary etc.) 55 // 2: provide vm dispatch behavior for the object 56 // Both functions are combined into one C++ class. 57 58 // One reason for the oop/klass dichotomy in the implementation is 59 // that we don't want a C++ vtbl pointer in every object. Thus, 60 // normal oops don't have any virtual functions. Instead, they 61 // forward all "virtual" functions to their klass, which does have 62 // a vtbl and does the C++ dispatch depending on the object's 63 // actual type. (See oop.inline.hpp for some of the forwarding code.) 64 // ALL FUNCTIONS IMPLEMENTING THIS DISPATCH ARE PREFIXED WITH "oop_"! 65 66 // Forward declarations. 67 template <class T> class Array; 68 template <class T> class GrowableArray; 69 class fieldDescriptor; 70 class KlassSizeStats; 71 class klassVtable; 72 class ModuleEntry; 73 class PackageEntry; 74 class ParCompactionManager; 75 class PSPromotionManager; 76 class vtableEntry; 77 78 class Klass : public Metadata { 79 friend class VMStructs; 80 friend class JVMCIVMStructs; 81 protected: 82 // If you add a new field that points to any metaspace object, you 83 // must add this field to Klass::metaspace_pointers_do(). 84 85 // note: put frequently-used fields together at start of klass structure 86 // for better cache behavior (may not make much of a difference but sure won't hurt) 87 enum { _primary_super_limit = 8 }; 88 89 // The "layout helper" is a combined descriptor of object layout. 90 // For klasses which are neither instance nor array, the value is zero. 91 // 92 // For instances, layout helper is a positive number, the instance size. 93 // This size is already passed through align_object_size and scaled to bytes. 94 // The low order bit is set if instances of this class cannot be 95 // allocated using the fastpath. 96 // 97 // For arrays, layout helper is a negative number, containing four 98 // distinct bytes, as follows: 99 // MSB:[tag, hsz, ebt, log2(esz)]:LSB 100 // where: 101 // tag is 0x80 if the elements are oops, 0xC0 if non-oops 102 // hsz is array header size in bytes (i.e., offset of first element) 103 // ebt is the BasicType of the elements 104 // esz is the element size in bytes 105 // This packed word is arranged so as to be quickly unpacked by the 106 // various fast paths that use the various subfields. 107 // 108 // The esz bits can be used directly by a SLL instruction, without masking. 109 // 110 // Note that the array-kind tag looks like 0x00 for instance klasses, 111 // since their length in bytes is always less than 24Mb. 112 // 113 // Final note: This comes first, immediately after C++ vtable, 114 // because it is frequently queried. 115 jint _layout_helper; 116 117 // Klass identifier used to implement devirtualized oop closure dispatching. 118 const KlassID _id; 119 120 // The fields _super_check_offset, _secondary_super_cache, _secondary_supers 121 // and _primary_supers all help make fast subtype checks. See big discussion 122 // in doc/server_compiler/checktype.txt 123 // 124 // Where to look to observe a supertype (it is &_secondary_super_cache for 125 // secondary supers, else is &_primary_supers[depth()]. 126 juint _super_check_offset; 127 128 // Class name. Instance classes: java/lang/String, etc. Array classes: [I, 129 // [Ljava/lang/String;, etc. Set to zero for all other kinds of classes. 130 Symbol* _name; 131 132 // Cache of last observed secondary supertype 133 Klass* _secondary_super_cache; 134 // Array of all secondary supertypes 135 Array<Klass*>* _secondary_supers; 136 // Ordered list of all primary supertypes 137 Klass* _primary_supers[_primary_super_limit]; 138 // java/lang/Class instance mirroring this class 139 OopHandle _java_mirror; 140 // Superclass 141 Klass* _super; 142 // First subclass (NULL if none); _subklass->next_sibling() is next one 143 Klass* _subklass; 144 // Sibling link (or NULL); links all subklasses of a klass 145 Klass* _next_sibling; 146 147 // All klasses loaded by a class loader are chained through these links 148 Klass* _next_link; 149 150 // The VM's representation of the ClassLoader used to load this class. 151 // Provide access the corresponding instance java.lang.ClassLoader. 152 ClassLoaderData* _class_loader_data; 153 154 jint _modifier_flags; // Processed access flags, for use by Class.getModifiers. 155 AccessFlags _access_flags; // Access flags. The class/interface distinction is stored here. 156 157 JFR_ONLY(DEFINE_TRACE_ID_FIELD;) 158 159 // Biased locking implementation and statistics 160 // (the 64-bit chunk goes first, to avoid some fragmentation) 161 jlong _last_biased_lock_bulk_revocation_time; 162 markOop _prototype_header; // Used when biased locking is both enabled and disabled for this type 163 jint _biased_lock_revocation_count; 164 165 // vtable length 166 int _vtable_len; 167 168 private: 169 // This is an index into FileMapHeader::_shared_path_table[], to 170 // associate this class with the JAR file where it's loaded from during 171 // dump time. If a class is not loaded from the shared archive, this field is 172 // -1. 173 jshort _shared_class_path_index; 174 175 #if INCLUDE_CDS 176 // Flags of the current shared class. 177 u2 _shared_class_flags; 178 enum { 179 _has_raw_archived_mirror = 1, 180 _has_signer_and_not_archived = 1 << 2 181 }; 182 #endif 183 // The _archived_mirror is set at CDS dump time pointing to the cached mirror 184 // in the open archive heap region when archiving java object is supported. 185 CDS_JAVA_HEAP_ONLY(narrowOop _archived_mirror;) 186 187 protected: 188 189 // Constructor 190 Klass(KlassID id); 191 Klass() : _id(KlassID(-1)) { assert(DumpSharedSpaces || UseSharedSpaces, "only for cds"); } 192 193 void* operator new(size_t size, ClassLoaderData* loader_data, size_t word_size, TRAPS) throw(); 194 195 public: 196 int id() { return _id; } 197 198 enum DefaultsLookupMode { find_defaults, skip_defaults }; 199 enum OverpassLookupMode { find_overpass, skip_overpass }; 200 enum StaticLookupMode { find_static, skip_static }; 201 enum PrivateLookupMode { find_private, skip_private }; 202 203 bool is_klass() const volatile { return true; } 204 205 // super 206 Klass* super() const { return _super; } 207 void set_super(Klass* k) { _super = k; } 208 209 // initializes _super link, _primary_supers & _secondary_supers arrays 210 void initialize_supers(Klass* k, Array<Klass*>* transitive_interfaces, TRAPS); 211 void initialize_supers_impl1(Klass* k); 212 void initialize_supers_impl2(Klass* k); 213 214 // klass-specific helper for initializing _secondary_supers 215 virtual GrowableArray<Klass*>* compute_secondary_supers(int num_extra_slots, 216 Array<Klass*>* transitive_interfaces); 217 218 // java_super is the Java-level super type as specified by Class.getSuperClass. 219 virtual Klass* java_super() const { return NULL; } 220 221 juint super_check_offset() const { return _super_check_offset; } 222 void set_super_check_offset(juint o) { _super_check_offset = o; } 223 224 Klass* secondary_super_cache() const { return _secondary_super_cache; } 225 void set_secondary_super_cache(Klass* k) { _secondary_super_cache = k; } 226 227 Array<Klass*>* secondary_supers() const { return _secondary_supers; } 228 void set_secondary_supers(Array<Klass*>* k) { _secondary_supers = k; } 229 230 // Return the element of the _super chain of the given depth. 231 // If there is no such element, return either NULL or this. 232 Klass* primary_super_of_depth(juint i) const { 233 assert(i < primary_super_limit(), "oob"); 234 Klass* super = _primary_supers[i]; 235 assert(super == NULL || super->super_depth() == i, "correct display"); 236 return super; 237 } 238 239 // Can this klass be a primary super? False for interfaces and arrays of 240 // interfaces. False also for arrays or classes with long super chains. 241 bool can_be_primary_super() const { 242 const juint secondary_offset = in_bytes(secondary_super_cache_offset()); 243 return super_check_offset() != secondary_offset; 244 } 245 virtual bool can_be_primary_super_slow() const; 246 247 // Returns number of primary supers; may be a number in the inclusive range [0, primary_super_limit]. 248 juint super_depth() const { 249 if (!can_be_primary_super()) { 250 return primary_super_limit(); 251 } else { 252 juint d = (super_check_offset() - in_bytes(primary_supers_offset())) / sizeof(Klass*); 253 assert(d < primary_super_limit(), "oob"); 254 assert(_primary_supers[d] == this, "proper init"); 255 return d; 256 } 257 } 258 259 // java mirror 260 oop java_mirror() const; 261 void set_java_mirror(Handle m); 262 263 oop archived_java_mirror_raw() NOT_CDS_JAVA_HEAP_RETURN_(NULL); // no GC barrier 264 narrowOop archived_java_mirror_raw_narrow() NOT_CDS_JAVA_HEAP_RETURN_(NULL); // no GC barrier 265 void set_archived_java_mirror_raw(oop m) NOT_CDS_JAVA_HEAP_RETURN; // no GC barrier 266 267 // Temporary mirror switch used by RedefineClasses 268 // Both mirrors are on the ClassLoaderData::_handles list already so no 269 // barriers are needed. 270 void set_java_mirror_handle(OopHandle mirror) { _java_mirror = mirror; } 271 OopHandle java_mirror_handle() const { 272 return _java_mirror; 273 } 274 275 // modifier flags 276 jint modifier_flags() const { return _modifier_flags; } 277 void set_modifier_flags(jint flags) { _modifier_flags = flags; } 278 279 // size helper 280 int layout_helper() const { return _layout_helper; } 281 void set_layout_helper(int lh) { _layout_helper = lh; } 282 283 // Note: for instances layout_helper() may include padding. 284 // Use InstanceKlass::contains_field_offset to classify field offsets. 285 286 // sub/superklass links 287 Klass* subklass() const { return _subklass; } 288 Klass* next_sibling() const { return _next_sibling; } 289 InstanceKlass* superklass() const; 290 void append_to_sibling_list(); // add newly created receiver to superklass' subklass list 291 292 void set_next_link(Klass* k) { _next_link = k; } 293 Klass* next_link() const { return _next_link; } // The next klass defined by the class loader. 294 295 // class loader data 296 ClassLoaderData* class_loader_data() const { return _class_loader_data; } 297 void set_class_loader_data(ClassLoaderData* loader_data) { _class_loader_data = loader_data; } 298 299 int shared_classpath_index() const { 300 return _shared_class_path_index; 301 }; 302 303 void set_shared_classpath_index(int index) { 304 _shared_class_path_index = index; 305 }; 306 307 void set_has_raw_archived_mirror() { 308 CDS_ONLY(_shared_class_flags |= _has_raw_archived_mirror;) 309 } 310 void clear_has_raw_archived_mirror() { 311 CDS_ONLY(_shared_class_flags &= ~_has_raw_archived_mirror;) 312 } 313 bool has_raw_archived_mirror() const { 314 CDS_ONLY(return (_shared_class_flags & _has_raw_archived_mirror) != 0;) 315 NOT_CDS(return false;) 316 } 317 #if INCLUDE_CDS 318 void set_has_signer_and_not_archived() { 319 _shared_class_flags |= _has_signer_and_not_archived; 320 } 321 bool has_signer_and_not_archived() const { 322 assert(DumpSharedSpaces, "dump time only"); 323 return (_shared_class_flags & _has_signer_and_not_archived) != 0; 324 } 325 #endif // INCLUDE_CDS 326 327 // Obtain the module or package for this class 328 virtual ModuleEntry* module() const = 0; 329 virtual PackageEntry* package() const = 0; 330 331 protected: // internal accessors 332 void set_subklass(Klass* s); 333 void set_next_sibling(Klass* s); 334 335 public: 336 337 // Compiler support 338 static ByteSize super_offset() { return in_ByteSize(offset_of(Klass, _super)); } 339 static ByteSize super_check_offset_offset() { return in_ByteSize(offset_of(Klass, _super_check_offset)); } 340 static ByteSize primary_supers_offset() { return in_ByteSize(offset_of(Klass, _primary_supers)); } 341 static ByteSize secondary_super_cache_offset() { return in_ByteSize(offset_of(Klass, _secondary_super_cache)); } 342 static ByteSize secondary_supers_offset() { return in_ByteSize(offset_of(Klass, _secondary_supers)); } 343 static ByteSize java_mirror_offset() { return in_ByteSize(offset_of(Klass, _java_mirror)); } 344 static ByteSize modifier_flags_offset() { return in_ByteSize(offset_of(Klass, _modifier_flags)); } 345 static ByteSize layout_helper_offset() { return in_ByteSize(offset_of(Klass, _layout_helper)); } 346 static ByteSize access_flags_offset() { return in_ByteSize(offset_of(Klass, _access_flags)); } 347 348 // Unpacking layout_helper: 349 enum { 350 _lh_neutral_value = 0, // neutral non-array non-instance value 351 _lh_instance_slow_path_bit = 0x01, 352 _lh_log2_element_size_shift = BitsPerByte*0, 353 _lh_log2_element_size_mask = BitsPerLong-1, 354 _lh_element_type_shift = BitsPerByte*1, 355 _lh_element_type_mask = right_n_bits(BitsPerByte), // shifted mask 356 _lh_header_size_shift = BitsPerByte*2, 357 _lh_header_size_mask = right_n_bits(BitsPerByte), // shifted mask 358 _lh_array_tag_bits = 2, 359 _lh_array_tag_shift = BitsPerInt - _lh_array_tag_bits, 360 _lh_array_tag_obj_value = ~0x01 // 0x80000000 >> 30 361 }; 362 363 static const unsigned int _lh_array_tag_type_value = 0Xffffffff; // ~0x00, // 0xC0000000 >> 30 364 365 static int layout_helper_size_in_bytes(jint lh) { 366 assert(lh > (jint)_lh_neutral_value, "must be instance"); 367 return (int) lh & ~_lh_instance_slow_path_bit; 368 } 369 static bool layout_helper_needs_slow_path(jint lh) { 370 assert(lh > (jint)_lh_neutral_value, "must be instance"); 371 return (lh & _lh_instance_slow_path_bit) != 0; 372 } 373 static bool layout_helper_is_instance(jint lh) { 374 return (jint)lh > (jint)_lh_neutral_value; 375 } 376 static bool layout_helper_is_array(jint lh) { 377 return (jint)lh < (jint)_lh_neutral_value; 378 } 379 static bool layout_helper_is_typeArray(jint lh) { 380 // _lh_array_tag_type_value == (lh >> _lh_array_tag_shift); 381 return (juint)lh >= (juint)(_lh_array_tag_type_value << _lh_array_tag_shift); 382 } 383 static bool layout_helper_is_objArray(jint lh) { 384 // _lh_array_tag_obj_value == (lh >> _lh_array_tag_shift); 385 return (jint)lh < (jint)(_lh_array_tag_type_value << _lh_array_tag_shift); 386 } 387 static int layout_helper_header_size(jint lh) { 388 assert(lh < (jint)_lh_neutral_value, "must be array"); 389 int hsize = (lh >> _lh_header_size_shift) & _lh_header_size_mask; 390 assert(hsize > 0 && hsize < (int)sizeof(oopDesc)*3, "sanity"); 391 return hsize; 392 } 393 static BasicType layout_helper_element_type(jint lh) { 394 assert(lh < (jint)_lh_neutral_value, "must be array"); 395 int btvalue = (lh >> _lh_element_type_shift) & _lh_element_type_mask; 396 assert(btvalue >= T_BOOLEAN && btvalue <= T_OBJECT, "sanity"); 397 return (BasicType) btvalue; 398 } 399 400 // Want a pattern to quickly diff against layout header in register 401 // find something less clever! 402 static int layout_helper_boolean_diffbit() { 403 jint zlh = array_layout_helper(T_BOOLEAN); 404 jint blh = array_layout_helper(T_BYTE); 405 assert(zlh != blh, "array layout helpers must differ"); 406 int diffbit = 1; 407 while ((diffbit & (zlh ^ blh)) == 0 && (diffbit & zlh) == 0) { 408 diffbit <<= 1; 409 assert(diffbit != 0, "make sure T_BOOLEAN has a different bit than T_BYTE"); 410 } 411 return diffbit; 412 } 413 414 static int layout_helper_log2_element_size(jint lh) { 415 assert(lh < (jint)_lh_neutral_value, "must be array"); 416 int l2esz = (lh >> _lh_log2_element_size_shift) & _lh_log2_element_size_mask; 417 assert(l2esz <= LogBytesPerLong, 418 "sanity. l2esz: 0x%x for lh: 0x%x", (uint)l2esz, (uint)lh); 419 return l2esz; 420 } 421 static jint array_layout_helper(jint tag, int hsize, BasicType etype, int log2_esize) { 422 return (tag << _lh_array_tag_shift) 423 | (hsize << _lh_header_size_shift) 424 | ((int)etype << _lh_element_type_shift) 425 | (log2_esize << _lh_log2_element_size_shift); 426 } 427 static jint instance_layout_helper(jint size, bool slow_path_flag) { 428 return (size << LogBytesPerWord) 429 | (slow_path_flag ? _lh_instance_slow_path_bit : 0); 430 } 431 static int layout_helper_to_size_helper(jint lh) { 432 assert(lh > (jint)_lh_neutral_value, "must be instance"); 433 // Note that the following expression discards _lh_instance_slow_path_bit. 434 return lh >> LogBytesPerWord; 435 } 436 // Out-of-line version computes everything based on the etype: 437 static jint array_layout_helper(BasicType etype); 438 439 // What is the maximum number of primary superclasses any klass can have? 440 #ifdef PRODUCT 441 static juint primary_super_limit() { return _primary_super_limit; } 442 #else 443 static juint primary_super_limit() { 444 assert(FastSuperclassLimit <= _primary_super_limit, "parameter oob"); 445 return FastSuperclassLimit; 446 } 447 #endif 448 449 // vtables 450 klassVtable vtable() const; 451 int vtable_length() const { return _vtable_len; } 452 453 // subclass check 454 bool is_subclass_of(const Klass* k) const; 455 // subtype check: true if is_subclass_of, or if k is interface and receiver implements it 456 bool is_subtype_of(Klass* k) const { 457 juint off = k->super_check_offset(); 458 Klass* sup = *(Klass**)( (address)this + off ); 459 const juint secondary_offset = in_bytes(secondary_super_cache_offset()); 460 if (sup == k) { 461 return true; 462 } else if (off != secondary_offset) { 463 return false; 464 } else { 465 return search_secondary_supers(k); 466 } 467 } 468 469 bool search_secondary_supers(Klass* k) const; 470 471 // Find LCA in class hierarchy 472 Klass *LCA( Klass *k ); 473 474 // Check whether reflection/jni/jvm code is allowed to instantiate this class; 475 // if not, throw either an Error or an Exception. 476 virtual void check_valid_for_instantiation(bool throwError, TRAPS); 477 478 // array copying 479 virtual void copy_array(arrayOop s, int src_pos, arrayOop d, int dst_pos, int length, TRAPS); 480 481 // tells if the class should be initialized 482 virtual bool should_be_initialized() const { return false; } 483 // initializes the klass 484 virtual void initialize(TRAPS); 485 // lookup operation for MethodLookupCache 486 friend class MethodLookupCache; 487 virtual Klass* find_field(Symbol* name, Symbol* signature, fieldDescriptor* fd) const; 488 virtual Method* uncached_lookup_method(const Symbol* name, const Symbol* signature, 489 OverpassLookupMode overpass_mode, 490 PrivateLookupMode = find_private) const; 491 public: 492 Method* lookup_method(const Symbol* name, const Symbol* signature) const { 493 return uncached_lookup_method(name, signature, find_overpass); 494 } 495 496 // array class with specific rank 497 Klass* array_klass(int rank, TRAPS) { return array_klass_impl(false, rank, THREAD); } 498 499 // array class with this klass as element type 500 Klass* array_klass(TRAPS) { return array_klass_impl(false, THREAD); } 501 502 // These will return NULL instead of allocating on the heap: 503 // NB: these can block for a mutex, like other functions with TRAPS arg. 504 Klass* array_klass_or_null(int rank); 505 Klass* array_klass_or_null(); 506 507 virtual oop protection_domain() const = 0; 508 509 oop class_loader() const; 510 511 virtual oop klass_holder() const { return class_loader(); } 512 513 protected: 514 virtual Klass* array_klass_impl(bool or_null, int rank, TRAPS); 515 virtual Klass* array_klass_impl(bool or_null, TRAPS); 516 517 void set_vtable_length(int len) { _vtable_len= len; } 518 519 vtableEntry* start_of_vtable() const; 520 public: 521 Method* method_at_vtable(int index); 522 523 static ByteSize vtable_start_offset(); 524 static ByteSize vtable_length_offset() { 525 return byte_offset_of(Klass, _vtable_len); 526 } 527 528 // CDS support - remove and restore oops from metadata. Oops are not shared. 529 virtual void remove_unshareable_info(); 530 virtual void remove_java_mirror(); 531 virtual void restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS); 532 533 protected: 534 // computes the subtype relationship 535 virtual bool compute_is_subtype_of(Klass* k); 536 public: 537 // subclass accessor (here for convenience; undefined for non-klass objects) 538 virtual bool is_leaf_class() const { fatal("not a class"); return false; } 539 public: 540 // ALL FUNCTIONS BELOW THIS POINT ARE DISPATCHED FROM AN OOP 541 // These functions describe behavior for the oop not the KLASS. 542 543 // actual oop size of obj in memory 544 virtual int oop_size(oop obj) const = 0; 545 546 // Size of klass in word size. 547 virtual int size() const = 0; 548 #if INCLUDE_SERVICES 549 virtual void collect_statistics(KlassSizeStats *sz) const; 550 #endif 551 552 // Returns the Java name for a class (Resource allocated) 553 // For arrays, this returns the name of the element with a leading '['. 554 // For classes, this returns the name with the package separators 555 // turned into '.'s. 556 const char* external_name() const; 557 // Returns the name for a class (Resource allocated) as the class 558 // would appear in a signature. 559 // For arrays, this returns the name of the element with a leading '['. 560 // For classes, this returns the name with a leading 'L' and a trailing ';' 561 // and the package separators as '/'. 562 virtual const char* signature_name() const; 563 564 const char* joint_in_module_of_loader(const Klass* class2, bool include_parent_loader = false) const; 565 const char* class_in_module_of_loader(bool use_are = false, bool include_parent_loader = false) const; 566 567 // Returns "interface", "abstract class" or "class". 568 const char* external_kind() const; 569 570 // type testing operations 571 #ifdef ASSERT 572 protected: 573 virtual bool is_instance_klass_slow() const { return false; } 574 virtual bool is_array_klass_slow() const { return false; } 575 virtual bool is_objArray_klass_slow() const { return false; } 576 virtual bool is_typeArray_klass_slow() const { return false; } 577 #endif // ASSERT 578 public: 579 580 // Fast non-virtual versions 581 #ifndef ASSERT 582 #define assert_same_query(xval, xcheck) xval 583 #else 584 private: 585 static bool assert_same_query(bool xval, bool xslow) { 586 assert(xval == xslow, "slow and fast queries agree"); 587 return xval; 588 } 589 public: 590 #endif 591 inline bool is_instance_klass() const { return assert_same_query( 592 layout_helper_is_instance(layout_helper()), 593 is_instance_klass_slow()); } 594 inline bool is_array_klass() const { return assert_same_query( 595 layout_helper_is_array(layout_helper()), 596 is_array_klass_slow()); } 597 inline bool is_objArray_klass() const { return assert_same_query( 598 layout_helper_is_objArray(layout_helper()), 599 is_objArray_klass_slow()); } 600 inline bool is_typeArray_klass() const { return assert_same_query( 601 layout_helper_is_typeArray(layout_helper()), 602 is_typeArray_klass_slow()); } 603 #undef assert_same_query 604 605 // Access flags 606 AccessFlags access_flags() const { return _access_flags; } 607 void set_access_flags(AccessFlags flags) { _access_flags = flags; } 608 609 bool is_public() const { return _access_flags.is_public(); } 610 bool is_final() const { return _access_flags.is_final(); } 611 bool is_interface() const { return _access_flags.is_interface(); } 612 bool is_abstract() const { return _access_flags.is_abstract(); } 613 bool is_super() const { return _access_flags.is_super(); } 614 bool is_synthetic() const { return _access_flags.is_synthetic(); } 615 void set_is_synthetic() { _access_flags.set_is_synthetic(); } 616 bool has_finalizer() const { return _access_flags.has_finalizer(); } 617 bool has_final_method() const { return _access_flags.has_final_method(); } 618 void set_has_finalizer() { _access_flags.set_has_finalizer(); } 619 void set_has_final_method() { _access_flags.set_has_final_method(); } 620 bool has_vanilla_constructor() const { return _access_flags.has_vanilla_constructor(); } 621 void set_has_vanilla_constructor() { _access_flags.set_has_vanilla_constructor(); } 622 bool has_miranda_methods () const { return access_flags().has_miranda_methods(); } 623 void set_has_miranda_methods() { _access_flags.set_has_miranda_methods(); } 624 bool is_shared() const { return access_flags().is_shared_class(); } // shadows MetaspaceObj::is_shared)() 625 void set_is_shared() { _access_flags.set_is_shared_class(); } 626 627 bool is_cloneable() const; 628 void set_is_cloneable(); 629 630 // Biased locking support 631 // Note: the prototype header is always set up to be at least the 632 // prototype markOop. If biased locking is enabled it may further be 633 // biasable and have an epoch. 634 markOop prototype_header() const { return _prototype_header; } 635 // NOTE: once instances of this klass are floating around in the 636 // system, this header must only be updated at a safepoint. 637 // NOTE 2: currently we only ever set the prototype header to the 638 // biasable prototype for instanceKlasses. There is no technical 639 // reason why it could not be done for arrayKlasses aside from 640 // wanting to reduce the initial scope of this optimization. There 641 // are potential problems in setting the bias pattern for 642 // JVM-internal oops. 643 inline void set_prototype_header(markOop header); 644 static ByteSize prototype_header_offset() { return in_ByteSize(offset_of(Klass, _prototype_header)); } 645 646 int biased_lock_revocation_count() const { return (int) _biased_lock_revocation_count; } 647 // Atomically increments biased_lock_revocation_count and returns updated value 648 int atomic_incr_biased_lock_revocation_count(); 649 void set_biased_lock_revocation_count(int val) { _biased_lock_revocation_count = (jint) val; } 650 jlong last_biased_lock_bulk_revocation_time() { return _last_biased_lock_bulk_revocation_time; } 651 void set_last_biased_lock_bulk_revocation_time(jlong cur_time) { _last_biased_lock_bulk_revocation_time = cur_time; } 652 653 JFR_ONLY(DEFINE_TRACE_ID_METHODS;) 654 655 virtual void metaspace_pointers_do(MetaspaceClosure* iter); 656 virtual MetaspaceObj::Type type() const { return ClassType; } 657 658 // Iff the class loader (or mirror for anonymous classes) is alive the 659 // Klass is considered alive. Has already been marked as unloading. 660 bool is_loader_alive() const { return !class_loader_data()->is_unloading(); } 661 662 // Load the klass's holder as a phantom. This is useful when a weak Klass 663 // pointer has been "peeked" and then must be kept alive before it may 664 // be used safely. 665 oop holder_phantom() const; 666 667 static void clean_weak_klass_links(bool unloading_occurred, bool clean_alive_klasses = true); 668 static void clean_subklass_tree() { 669 clean_weak_klass_links(/*unloading_occurred*/ true , /* clean_alive_klasses */ false); 670 } 671 672 // GC specific object visitors 673 // 674 #if INCLUDE_PARALLELGC 675 // Parallel Scavenge 676 virtual void oop_ps_push_contents( oop obj, PSPromotionManager* pm) = 0; 677 // Parallel Compact 678 virtual void oop_pc_follow_contents(oop obj, ParCompactionManager* cm) = 0; 679 virtual void oop_pc_update_pointers(oop obj, ParCompactionManager* cm) = 0; 680 #endif 681 682 virtual void array_klasses_do(void f(Klass* k)) {} 683 684 // Return self, except for abstract classes with exactly 1 685 // implementor. Then return the 1 concrete implementation. 686 Klass *up_cast_abstract(); 687 688 // klass name 689 Symbol* name() const { return _name; } 690 void set_name(Symbol* n); 691 692 public: 693 // jvm support 694 virtual jint compute_modifier_flags(TRAPS) const; 695 696 // JVMTI support 697 virtual jint jvmti_class_status() const; 698 699 // Printing 700 virtual void print_on(outputStream* st) const; 701 702 virtual void oop_print_value_on(oop obj, outputStream* st); 703 virtual void oop_print_on (oop obj, outputStream* st); 704 705 virtual const char* internal_name() const = 0; 706 707 // Verification 708 virtual void verify_on(outputStream* st); 709 void verify() { verify_on(tty); } 710 711 #ifndef PRODUCT 712 bool verify_vtable_index(int index); 713 bool verify_itable_index(int index); 714 #endif 715 716 virtual void oop_verify_on(oop obj, outputStream* st); 717 718 static bool is_null(narrowKlass obj); 719 static bool is_null(Klass* obj); 720 721 // klass encoding for klass pointer in objects. 722 static narrowKlass encode_klass_not_null(Klass* v); 723 static narrowKlass encode_klass(Klass* v); 724 725 static Klass* decode_klass_not_null(narrowKlass v); 726 static Klass* decode_klass(narrowKlass v); 727 }; 728 729 #endif // SHARE_VM_OOPS_KLASS_HPP