1 /* 2 * Copyright (c) 1997, 2024, 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_OOPS_KLASS_HPP 26 #define SHARE_OOPS_KLASS_HPP 27 28 #include "memory/iterator.hpp" 29 #include "memory/memRegion.hpp" 30 #include "oops/markWord.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 // 41 // A Klass provides: 42 // 1: language level class object (method dictionary etc.) 43 // 2: provide vm dispatch behavior for the object 44 // Both functions are combined into one C++ class. 45 46 // One reason for the oop/klass dichotomy in the implementation is 47 // that we don't want a C++ vtbl pointer in every object. Thus, 48 // normal oops don't have any virtual functions. Instead, they 49 // forward all "virtual" functions to their klass, which does have 50 // a vtbl and does the C++ dispatch depending on the object's 51 // actual type. (See oop.inline.hpp for some of the forwarding code.) 52 // ALL FUNCTIONS IMPLEMENTING THIS DISPATCH ARE PREFIXED WITH "oop_"! 53 54 // Forward declarations. 55 template <class T> class Array; 56 template <class T> class GrowableArray; 57 class ClassLoaderData; 58 class fieldDescriptor; 59 class klassVtable; 60 class ModuleEntry; 61 class PackageEntry; 62 class ParCompactionManager; 63 class PSPromotionManager; 64 class vtableEntry; 65 66 class Klass : public Metadata { 67 friend class VMStructs; 68 friend class JVMCIVMStructs; 69 public: 70 // Klass Kinds for all subclasses of Klass 71 enum KlassKind { 72 InstanceKlassKind, 73 InstanceRefKlassKind, 74 InstanceMirrorKlassKind, 75 InstanceClassLoaderKlassKind, 76 InstanceStackChunkKlassKind, 77 TypeArrayKlassKind, 78 ObjArrayKlassKind, 79 UnknownKlassKind 80 }; 81 82 static const uint KLASS_KIND_COUNT = ObjArrayKlassKind + 1; 83 protected: 84 85 // If you add a new field that points to any metaspace object, you 86 // must add this field to Klass::metaspace_pointers_do(). 87 88 // note: put frequently-used fields together at start of klass structure 89 // for better cache behavior (may not make much of a difference but sure won't hurt) 90 enum { _primary_super_limit = 8 }; 91 92 // The "layout helper" is a combined descriptor of object layout. 93 // For klasses which are neither instance nor array, the value is zero. 94 // 95 // For instances, layout helper is a positive number, the instance size. 96 // This size is already passed through align_object_size and scaled to bytes. 97 // The low order bit is set if instances of this class cannot be 98 // allocated using the fastpath. 99 // 100 // For arrays, layout helper is a negative number, containing four 101 // distinct bytes, as follows: 102 // MSB:[tag, hsz, ebt, log2(esz)]:LSB 103 // where: 104 // tag is 0x80 if the elements are oops, 0xC0 if non-oops 105 // hsz is array header size in bytes (i.e., offset of first element) 106 // ebt is the BasicType of the elements 107 // esz is the element size in bytes 108 // This packed word is arranged so as to be quickly unpacked by the 109 // various fast paths that use the various subfields. 110 // 111 // The esz bits can be used directly by a SLL instruction, without masking. 112 // 113 // Note that the array-kind tag looks like 0x00 for instance klasses, 114 // since their length in bytes is always less than 24Mb. 115 // 116 // Final note: This comes first, immediately after C++ vtable, 117 // because it is frequently queried. 118 jint _layout_helper; 119 120 // Klass kind used to resolve the runtime type of the instance. 121 // - Used to implement devirtualized oop closure dispatching. 122 // - Various type checking in the JVM 123 const KlassKind _kind; 124 125 // Processed access flags, for use by Class.getModifiers. 126 jint _modifier_flags; 127 128 // The fields _super_check_offset, _secondary_super_cache, _secondary_supers 129 // and _primary_supers all help make fast subtype checks. See big discussion 130 // in doc/server_compiler/checktype.txt 131 // 132 // Where to look to observe a supertype (it is &_secondary_super_cache for 133 // secondary supers, else is &_primary_supers[depth()]. 134 juint _super_check_offset; 135 136 // Class name. Instance classes: java/lang/String, etc. Array classes: [I, 137 // [Ljava/lang/String;, etc. Set to zero for all other kinds of classes. 138 Symbol* _name; 139 140 // Cache of last observed secondary supertype 141 Klass* _secondary_super_cache; 142 // Array of all secondary supertypes 143 Array<Klass*>* _secondary_supers; 144 // Ordered list of all primary supertypes 145 Klass* _primary_supers[_primary_super_limit]; 146 // java/lang/Class instance mirroring this class 147 OopHandle _java_mirror; 148 // Superclass 149 Klass* _super; 150 // First subclass (null if none); _subklass->next_sibling() is next one 151 Klass* volatile _subklass; 152 // Sibling link (or null); links all subklasses of a klass 153 Klass* volatile _next_sibling; 154 155 // All klasses loaded by a class loader are chained through these links 156 Klass* _next_link; 157 158 // The VM's representation of the ClassLoader used to load this class. 159 // Provide access the corresponding instance java.lang.ClassLoader. 160 ClassLoaderData* _class_loader_data; 161 162 int _vtable_len; // vtable length. This field may be read very often when we 163 // have lots of itable dispatches (e.g., lambdas and streams). 164 // Keep it away from the beginning of a Klass to avoid cacheline 165 // contention that may happen when a nearby object is modified. 166 AccessFlags _access_flags; // Access flags. The class/interface distinction is stored here. 167 168 JFR_ONLY(DEFINE_TRACE_ID_FIELD;) 169 170 private: 171 // This is an index into FileMapHeader::_shared_path_table[], to 172 // associate this class with the JAR file where it's loaded from during 173 // dump time. If a class is not loaded from the shared archive, this field is 174 // -1. 175 s2 _shared_class_path_index; 176 177 #if INCLUDE_CDS 178 // Various attributes for shared classes. Should be zero for a non-shared class. 179 u2 _shared_class_flags; 180 enum CDSSharedClassFlags { 181 _is_shared_class = 1 << 0, // shadows MetaspaceObj::is_shared 182 _archived_lambda_proxy_is_available = 1 << 1, 183 _has_value_based_class_annotation = 1 << 2, 184 _verified_at_dump_time = 1 << 3, 185 _has_archived_enum_objs = 1 << 4, 186 // This class was not loaded from a classfile in the module image 187 // or classpath. 188 _is_generated_shared_class = 1 << 5 189 }; 190 #endif 191 192 CDS_JAVA_HEAP_ONLY(int _archived_mirror_index;) 193 194 protected: 195 196 Klass(KlassKind kind); 197 Klass(); 198 199 void* operator new(size_t size, ClassLoaderData* loader_data, size_t word_size, TRAPS) throw(); 200 201 public: 202 int kind() { return _kind; } 203 204 enum class DefaultsLookupMode { find, skip }; 205 enum class OverpassLookupMode { find, skip }; 206 enum class StaticLookupMode { find, skip }; 207 enum class PrivateLookupMode { find, skip }; 208 209 virtual bool is_klass() const { return true; } 210 211 // super() cannot be InstanceKlass* -- Java arrays are covariant, and _super is used 212 // to implement that. NB: the _super of "[Ljava/lang/Integer;" is "[Ljava/lang/Number;" 213 // If this is not what your code expects, you're probably looking for Klass::java_super(). 214 Klass* super() const { return _super; } 215 void set_super(Klass* k) { _super = k; } 216 217 // initializes _super link, _primary_supers & _secondary_supers arrays 218 void initialize_supers(Klass* k, Array<InstanceKlass*>* transitive_interfaces, TRAPS); 219 220 // klass-specific helper for initializing _secondary_supers 221 virtual GrowableArray<Klass*>* compute_secondary_supers(int num_extra_slots, 222 Array<InstanceKlass*>* transitive_interfaces); 223 224 // java_super is the Java-level super type as specified by Class.getSuperClass. 225 virtual InstanceKlass* java_super() const { return nullptr; } 226 227 juint super_check_offset() const { return _super_check_offset; } 228 void set_super_check_offset(juint o) { _super_check_offset = o; } 229 230 Klass* secondary_super_cache() const { return _secondary_super_cache; } 231 void set_secondary_super_cache(Klass* k) { _secondary_super_cache = k; } 232 233 Array<Klass*>* secondary_supers() const { return _secondary_supers; } 234 void set_secondary_supers(Array<Klass*>* k) { _secondary_supers = k; } 235 236 // Return the element of the _super chain of the given depth. 237 // If there is no such element, return either null or this. 238 Klass* primary_super_of_depth(juint i) const { 239 assert(i < primary_super_limit(), "oob"); 240 Klass* super = _primary_supers[i]; 241 assert(super == nullptr || super->super_depth() == i, "correct display"); 242 return super; 243 } 244 245 // Can this klass be a primary super? False for interfaces and arrays of 246 // interfaces. False also for arrays or classes with long super chains. 247 bool can_be_primary_super() const { 248 const juint secondary_offset = in_bytes(secondary_super_cache_offset()); 249 return super_check_offset() != secondary_offset; 250 } 251 virtual bool can_be_primary_super_slow() const; 252 253 // Returns number of primary supers; may be a number in the inclusive range [0, primary_super_limit]. 254 juint super_depth() const { 255 if (!can_be_primary_super()) { 256 return primary_super_limit(); 257 } else { 258 juint d = (super_check_offset() - in_bytes(primary_supers_offset())) / sizeof(Klass*); 259 assert(d < primary_super_limit(), "oob"); 260 assert(_primary_supers[d] == this, "proper init"); 261 return d; 262 } 263 } 264 265 // java mirror 266 oop java_mirror() const; 267 oop java_mirror_no_keepalive() const; 268 void set_java_mirror(Handle m); 269 270 oop archived_java_mirror() NOT_CDS_JAVA_HEAP_RETURN_(nullptr); 271 void set_archived_java_mirror(int mirror_index) NOT_CDS_JAVA_HEAP_RETURN; 272 273 // Temporary mirror switch used by RedefineClasses 274 OopHandle java_mirror_handle() const { return _java_mirror; } 275 void swap_java_mirror_handle(OopHandle& mirror) { _java_mirror.swap(mirror); } 276 277 // Set java mirror OopHandle to null for CDS 278 // This leaves the OopHandle in the CLD, but that's ok, you can't release them. 279 void clear_java_mirror_handle() { _java_mirror = OopHandle(); } 280 281 // modifier flags 282 jint modifier_flags() const { return _modifier_flags; } 283 void set_modifier_flags(jint flags) { _modifier_flags = flags; } 284 285 // size helper 286 int layout_helper() const { return _layout_helper; } 287 void set_layout_helper(int lh) { _layout_helper = lh; } 288 289 // Note: for instances layout_helper() may include padding. 290 // Use InstanceKlass::contains_field_offset to classify field offsets. 291 292 // sub/superklass links 293 Klass* subklass(bool log = false) const; 294 Klass* next_sibling(bool log = false) const; 295 296 InstanceKlass* superklass() const; 297 void append_to_sibling_list(); // add newly created receiver to superklass' subklass list 298 299 void set_next_link(Klass* k) { _next_link = k; } 300 Klass* next_link() const { return _next_link; } // The next klass defined by the class loader. 301 Klass** next_link_addr() { return &_next_link; } 302 303 // class loader data 304 ClassLoaderData* class_loader_data() const { return _class_loader_data; } 305 void set_class_loader_data(ClassLoaderData* loader_data) { _class_loader_data = loader_data; } 306 307 s2 shared_classpath_index() const { 308 return _shared_class_path_index; 309 }; 310 311 void set_shared_classpath_index(s2 index) { 312 _shared_class_path_index = index; 313 }; 314 315 bool has_archived_mirror_index() const { 316 CDS_JAVA_HEAP_ONLY(return _archived_mirror_index >= 0;) 317 NOT_CDS_JAVA_HEAP(return false); 318 } 319 320 void clear_archived_mirror_index() NOT_CDS_JAVA_HEAP_RETURN; 321 322 void set_lambda_proxy_is_available() { 323 CDS_ONLY(_shared_class_flags |= _archived_lambda_proxy_is_available;) 324 } 325 void clear_lambda_proxy_is_available() { 326 CDS_ONLY(_shared_class_flags &= (u2)(~_archived_lambda_proxy_is_available);) 327 } 328 bool lambda_proxy_is_available() const { 329 CDS_ONLY(return (_shared_class_flags & _archived_lambda_proxy_is_available) != 0;) 330 NOT_CDS(return false;) 331 } 332 333 void set_has_value_based_class_annotation() { 334 CDS_ONLY(_shared_class_flags |= _has_value_based_class_annotation;) 335 } 336 void clear_has_value_based_class_annotation() { 337 CDS_ONLY(_shared_class_flags &= (u2)(~_has_value_based_class_annotation);) 338 } 339 bool has_value_based_class_annotation() const { 340 CDS_ONLY(return (_shared_class_flags & _has_value_based_class_annotation) != 0;) 341 NOT_CDS(return false;) 342 } 343 344 void set_verified_at_dump_time() { 345 CDS_ONLY(_shared_class_flags |= _verified_at_dump_time;) 346 } 347 bool verified_at_dump_time() const { 348 CDS_ONLY(return (_shared_class_flags & _verified_at_dump_time) != 0;) 349 NOT_CDS(return false;) 350 } 351 352 void set_has_archived_enum_objs() { 353 CDS_ONLY(_shared_class_flags |= _has_archived_enum_objs;) 354 } 355 bool has_archived_enum_objs() const { 356 CDS_ONLY(return (_shared_class_flags & _has_archived_enum_objs) != 0;) 357 NOT_CDS(return false;) 358 } 359 360 void set_is_generated_shared_class() { 361 CDS_ONLY(_shared_class_flags |= _is_generated_shared_class;) 362 } 363 bool is_generated_shared_class() const { 364 CDS_ONLY(return (_shared_class_flags & _is_generated_shared_class) != 0;) 365 NOT_CDS(return false;) 366 } 367 368 bool is_shared() const { // shadows MetaspaceObj::is_shared)() 369 CDS_ONLY(return (_shared_class_flags & _is_shared_class) != 0;) 370 NOT_CDS(return false;) 371 } 372 373 void set_is_shared() { 374 CDS_ONLY(_shared_class_flags |= _is_shared_class;) 375 } 376 377 // Obtain the module or package for this class 378 virtual ModuleEntry* module() const = 0; 379 virtual PackageEntry* package() const = 0; 380 381 protected: // internal accessors 382 void set_subklass(Klass* s); 383 void set_next_sibling(Klass* s); 384 385 public: 386 387 // Compiler support 388 static ByteSize super_offset() { return byte_offset_of(Klass, _super); } 389 static ByteSize super_check_offset_offset() { return byte_offset_of(Klass, _super_check_offset); } 390 static ByteSize primary_supers_offset() { return byte_offset_of(Klass, _primary_supers); } 391 static ByteSize secondary_super_cache_offset() { return byte_offset_of(Klass, _secondary_super_cache); } 392 static ByteSize secondary_supers_offset() { return byte_offset_of(Klass, _secondary_supers); } 393 static ByteSize java_mirror_offset() { return byte_offset_of(Klass, _java_mirror); } 394 static ByteSize class_loader_data_offset() { return byte_offset_of(Klass, _class_loader_data); } 395 static ByteSize modifier_flags_offset() { return byte_offset_of(Klass, _modifier_flags); } 396 static ByteSize layout_helper_offset() { return byte_offset_of(Klass, _layout_helper); } 397 static ByteSize access_flags_offset() { return byte_offset_of(Klass, _access_flags); } 398 #if INCLUDE_JVMCI 399 static ByteSize subklass_offset() { return byte_offset_of(Klass, _subklass); } 400 static ByteSize next_sibling_offset() { return byte_offset_of(Klass, _next_sibling); } 401 #endif 402 403 // Unpacking layout_helper: 404 static const int _lh_neutral_value = 0; // neutral non-array non-instance value 405 static const int _lh_instance_slow_path_bit = 0x01; 406 static const int _lh_log2_element_size_shift = BitsPerByte*0; 407 static const int _lh_log2_element_size_mask = BitsPerLong-1; 408 static const int _lh_element_type_shift = BitsPerByte*1; 409 static const int _lh_element_type_mask = right_n_bits(BitsPerByte); // shifted mask 410 static const int _lh_header_size_shift = BitsPerByte*2; 411 static const int _lh_header_size_mask = right_n_bits(BitsPerByte); // shifted mask 412 static const int _lh_array_tag_bits = 2; 413 static const int _lh_array_tag_shift = BitsPerInt - _lh_array_tag_bits; 414 static const int _lh_array_tag_obj_value = ~0x01; // 0x80000000 >> 30 415 416 static const unsigned int _lh_array_tag_type_value = 0Xffffffff; // ~0x00, // 0xC0000000 >> 30 417 418 static int layout_helper_size_in_bytes(jint lh) { 419 assert(lh > (jint)_lh_neutral_value, "must be instance"); 420 return (int) lh & ~_lh_instance_slow_path_bit; 421 } 422 static bool layout_helper_needs_slow_path(jint lh) { 423 assert(lh > (jint)_lh_neutral_value, "must be instance"); 424 return (lh & _lh_instance_slow_path_bit) != 0; 425 } 426 static bool layout_helper_is_instance(jint lh) { 427 return (jint)lh > (jint)_lh_neutral_value; 428 } 429 static bool layout_helper_is_array(jint lh) { 430 return (jint)lh < (jint)_lh_neutral_value; 431 } 432 static bool layout_helper_is_typeArray(jint lh) { 433 // _lh_array_tag_type_value == (lh >> _lh_array_tag_shift); 434 return (juint)lh >= (juint)(_lh_array_tag_type_value << _lh_array_tag_shift); 435 } 436 static bool layout_helper_is_objArray(jint lh) { 437 // _lh_array_tag_obj_value == (lh >> _lh_array_tag_shift); 438 return (jint)lh < (jint)(_lh_array_tag_type_value << _lh_array_tag_shift); 439 } 440 static int layout_helper_header_size(jint lh) { 441 assert(lh < (jint)_lh_neutral_value, "must be array"); 442 int hsize = (lh >> _lh_header_size_shift) & _lh_header_size_mask; 443 assert(hsize > 0 && hsize < (int)sizeof(oopDesc)*3, "sanity"); 444 return hsize; 445 } 446 static BasicType layout_helper_element_type(jint lh) { 447 assert(lh < (jint)_lh_neutral_value, "must be array"); 448 int btvalue = (lh >> _lh_element_type_shift) & _lh_element_type_mask; 449 assert(btvalue >= T_BOOLEAN && btvalue <= T_OBJECT, "sanity"); 450 return (BasicType) btvalue; 451 } 452 453 // Want a pattern to quickly diff against layout header in register 454 // find something less clever! 455 static int layout_helper_boolean_diffbit() { 456 jint zlh = array_layout_helper(T_BOOLEAN); 457 jint blh = array_layout_helper(T_BYTE); 458 assert(zlh != blh, "array layout helpers must differ"); 459 int diffbit = 1; 460 while ((diffbit & (zlh ^ blh)) == 0 && (diffbit & zlh) == 0) { 461 diffbit <<= 1; 462 assert(diffbit != 0, "make sure T_BOOLEAN has a different bit than T_BYTE"); 463 } 464 return diffbit; 465 } 466 467 static int layout_helper_log2_element_size(jint lh) { 468 assert(lh < (jint)_lh_neutral_value, "must be array"); 469 int l2esz = (lh >> _lh_log2_element_size_shift) & _lh_log2_element_size_mask; 470 assert(l2esz <= LogBytesPerLong, 471 "sanity. l2esz: 0x%x for lh: 0x%x", (uint)l2esz, (uint)lh); 472 return l2esz; 473 } 474 static jint array_layout_helper(jint tag, int hsize, BasicType etype, int log2_esize) { 475 return (tag << _lh_array_tag_shift) 476 | (hsize << _lh_header_size_shift) 477 | ((int)etype << _lh_element_type_shift) 478 | (log2_esize << _lh_log2_element_size_shift); 479 } 480 static jint instance_layout_helper(jint size, bool slow_path_flag) { 481 return (size << LogBytesPerWord) 482 | (slow_path_flag ? _lh_instance_slow_path_bit : 0); 483 } 484 static int layout_helper_to_size_helper(jint lh) { 485 assert(lh > (jint)_lh_neutral_value, "must be instance"); 486 // Note that the following expression discards _lh_instance_slow_path_bit. 487 return lh >> LogBytesPerWord; 488 } 489 // Out-of-line version computes everything based on the etype: 490 static jint array_layout_helper(BasicType etype); 491 492 // What is the maximum number of primary superclasses any klass can have? 493 static juint primary_super_limit() { return _primary_super_limit; } 494 495 // vtables 496 klassVtable vtable() const; 497 int vtable_length() const { return _vtable_len; } 498 499 // subclass check 500 bool is_subclass_of(const Klass* k) const; 501 // subtype check: true if is_subclass_of, or if k is interface and receiver implements it 502 bool is_subtype_of(Klass* k) const { 503 juint off = k->super_check_offset(); 504 Klass* sup = *(Klass**)( (address)this + off ); 505 const juint secondary_offset = in_bytes(secondary_super_cache_offset()); 506 if (sup == k) { 507 return true; 508 } else if (off != secondary_offset) { 509 return false; 510 } else { 511 return search_secondary_supers(k); 512 } 513 } 514 515 bool search_secondary_supers(Klass* k) const; 516 517 // Find LCA in class hierarchy 518 Klass *LCA( Klass *k ); 519 520 // Check whether reflection/jni/jvm code is allowed to instantiate this class; 521 // if not, throw either an Error or an Exception. 522 virtual void check_valid_for_instantiation(bool throwError, TRAPS); 523 524 // array copying 525 virtual void copy_array(arrayOop s, int src_pos, arrayOop d, int dst_pos, int length, TRAPS); 526 527 // tells if the class should be initialized 528 virtual bool should_be_initialized() const { return false; } 529 // initializes the klass 530 virtual void initialize(TRAPS); 531 virtual Klass* find_field(Symbol* name, Symbol* signature, fieldDescriptor* fd) const; 532 virtual Method* uncached_lookup_method(const Symbol* name, const Symbol* signature, 533 OverpassLookupMode overpass_mode, 534 PrivateLookupMode = PrivateLookupMode::find) const; 535 public: 536 Method* lookup_method(const Symbol* name, const Symbol* signature) const { 537 return uncached_lookup_method(name, signature, OverpassLookupMode::find); 538 } 539 540 // array class with specific rank 541 virtual ArrayKlass* array_klass(int rank, TRAPS) = 0; 542 543 // array class with this klass as element type 544 virtual ArrayKlass* array_klass(TRAPS) = 0; 545 546 // These will return null instead of allocating on the heap: 547 virtual ArrayKlass* array_klass_or_null(int rank) = 0; 548 virtual ArrayKlass* array_klass_or_null() = 0; 549 550 virtual oop protection_domain() const = 0; 551 552 oop class_loader() const; 553 554 inline oop klass_holder() const; 555 556 protected: 557 558 // Error handling when length > max_length or length < 0 559 static void check_array_allocation_length(int length, int max_length, TRAPS); 560 561 void set_vtable_length(int len) { _vtable_len= len; } 562 563 vtableEntry* start_of_vtable() const; 564 #if INCLUDE_CDS 565 void restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS); 566 #endif 567 public: 568 Method* method_at_vtable(int index); 569 570 static ByteSize vtable_start_offset(); 571 static ByteSize vtable_length_offset() { 572 return byte_offset_of(Klass, _vtable_len); 573 } 574 575 #if INCLUDE_CDS 576 // CDS support - remove and restore oops from metadata. Oops are not shared. 577 virtual void remove_unshareable_info(); 578 virtual void remove_java_mirror(); 579 580 bool is_unshareable_info_restored() const { 581 assert(is_shared(), "use this for shared classes only"); 582 if (has_archived_mirror_index()) { 583 // _java_mirror is not a valid OopHandle but rather an encoded reference in the shared heap 584 return false; 585 } else if (_java_mirror.is_empty()) { 586 return false; 587 } else { 588 return true; 589 } 590 } 591 #endif // INCLUDE_CDS 592 593 public: 594 // ALL FUNCTIONS BELOW THIS POINT ARE DISPATCHED FROM AN OOP 595 // These functions describe behavior for the oop not the KLASS. 596 597 // actual oop size of obj in memory in word size. 598 virtual size_t oop_size(oop obj) const = 0; 599 600 // Size of klass in word size. 601 virtual int size() const = 0; 602 603 // Returns the Java name for a class (Resource allocated) 604 // For arrays, this returns the name of the element with a leading '['. 605 // For classes, this returns the name with the package separators 606 // turned into '.'s. 607 const char* external_name() const; 608 // Returns the name for a class (Resource allocated) as the class 609 // would appear in a signature. 610 // For arrays, this returns the name of the element with a leading '['. 611 // For classes, this returns the name with a leading 'L' and a trailing ';' 612 // and the package separators as '/'. 613 virtual const char* signature_name() const; 614 615 const char* joint_in_module_of_loader(const Klass* class2, bool include_parent_loader = false) const; 616 const char* class_in_module_of_loader(bool use_are = false, bool include_parent_loader = false) const; 617 618 // Returns "interface", "abstract class" or "class". 619 const char* external_kind() const; 620 621 // type testing operations 622 #ifdef ASSERT 623 protected: 624 virtual bool is_instance_klass_slow() const { return false; } 625 virtual bool is_array_klass_slow() const { return false; } 626 virtual bool is_objArray_klass_slow() const { return false; } 627 virtual bool is_typeArray_klass_slow() const { return false; } 628 #endif // ASSERT 629 public: 630 631 // Fast non-virtual versions 632 #ifndef ASSERT 633 #define assert_same_query(xval, xcheck) xval 634 #else 635 private: 636 static bool assert_same_query(bool xval, bool xslow) { 637 assert(xval == xslow, "slow and fast queries agree"); 638 return xval; 639 } 640 public: 641 #endif 642 643 bool is_instance_klass() const { return assert_same_query(_kind <= InstanceStackChunkKlassKind, is_instance_klass_slow()); } 644 // Other is anything that is not one of the more specialized kinds of InstanceKlass. 645 bool is_other_instance_klass() const { return _kind == InstanceKlassKind; } 646 bool is_reference_instance_klass() const { return _kind == InstanceRefKlassKind; } 647 bool is_mirror_instance_klass() const { return _kind == InstanceMirrorKlassKind; } 648 bool is_class_loader_instance_klass() const { return _kind == InstanceClassLoaderKlassKind; } 649 bool is_array_klass() const { return assert_same_query( _kind >= TypeArrayKlassKind, is_array_klass_slow()); } 650 bool is_stack_chunk_instance_klass() const { return _kind == InstanceStackChunkKlassKind; } 651 bool is_objArray_klass() const { return assert_same_query( _kind == ObjArrayKlassKind, is_objArray_klass_slow()); } 652 bool is_typeArray_klass() const { return assert_same_query( _kind == TypeArrayKlassKind, is_typeArray_klass_slow()); } 653 #undef assert_same_query 654 655 // Access flags 656 AccessFlags access_flags() const { return _access_flags; } 657 void set_access_flags(AccessFlags flags) { _access_flags = flags; } 658 659 bool is_public() const { return _access_flags.is_public(); } 660 bool is_final() const { return _access_flags.is_final(); } 661 bool is_interface() const { return _access_flags.is_interface(); } 662 bool is_abstract() const { return _access_flags.is_abstract(); } 663 bool is_super() const { return _access_flags.is_super(); } 664 bool is_synthetic() const { return _access_flags.is_synthetic(); } 665 void set_is_synthetic() { _access_flags.set_is_synthetic(); } 666 bool has_finalizer() const { return _access_flags.has_finalizer(); } 667 void set_has_finalizer() { _access_flags.set_has_finalizer(); } 668 bool is_hidden() const { return access_flags().is_hidden_class(); } 669 void set_is_hidden() { _access_flags.set_is_hidden_class(); } 670 bool is_value_based() { return _access_flags.is_value_based_class(); } 671 void set_is_value_based() { _access_flags.set_is_value_based_class(); } 672 673 inline bool is_non_strong_hidden() const; 674 675 bool is_cloneable() const; 676 void set_is_cloneable(); 677 678 JFR_ONLY(DEFINE_TRACE_ID_METHODS;) 679 680 virtual void metaspace_pointers_do(MetaspaceClosure* iter); 681 virtual MetaspaceObj::Type type() const { return ClassType; } 682 683 inline bool is_loader_alive() const; 684 685 void clean_subklass(); 686 687 static void clean_weak_klass_links(bool unloading_occurred, bool clean_alive_klasses = true); 688 static void clean_subklass_tree() { 689 clean_weak_klass_links(/*unloading_occurred*/ true , /* clean_alive_klasses */ false); 690 } 691 692 // Return self, except for abstract classes with exactly 1 693 // implementor. Then return the 1 concrete implementation. 694 Klass *up_cast_abstract(); 695 696 // klass name 697 Symbol* name() const { return _name; } 698 void set_name(Symbol* n); 699 700 virtual void release_C_heap_structures(bool release_constant_pool = true); 701 702 public: 703 virtual jint compute_modifier_flags() const = 0; 704 705 // JVMTI support 706 virtual jint jvmti_class_status() const; 707 708 // Printing 709 virtual void print_on(outputStream* st) const; 710 711 virtual void oop_print_value_on(oop obj, outputStream* st); 712 virtual void oop_print_on (oop obj, outputStream* st); 713 714 virtual const char* internal_name() const = 0; 715 716 // Verification 717 virtual void verify_on(outputStream* st); 718 void verify() { verify_on(tty); } 719 720 #ifndef PRODUCT 721 bool verify_vtable_index(int index); 722 #endif 723 724 virtual void oop_verify_on(oop obj, outputStream* st); 725 726 // for error reporting 727 static bool is_valid(Klass* k); 728 }; 729 730 #endif // SHARE_OOPS_KLASS_HPP