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; 161 162 163 int _vtable_len; // vtable length. This field may be read very often when we 164 // have lots of itable dispatches (e.g., lambdas and streams). 165 // Keep it away from the beginning of a Klass to avoid cacheline 166 // contention that may happen when a nearby object is modified. 167 AccessFlags _access_flags; // Access flags. The class/interface distinction is stored here. 168 169 JFR_ONLY(DEFINE_TRACE_ID_FIELD;) 170 171 // Bitmap and hash code used by hashed secondary supers. 172 uintx _bitmap; 173 uint8_t _hash_slot; 174 175 private: 176 // This is an index into FileMapHeader::_shared_path_table[], to 177 // associate this class with the JAR file where it's loaded from during 178 // dump time. If a class is not loaded from the shared archive, this field is 179 // -1. 180 s2 _shared_class_path_index; 181 182 #if INCLUDE_CDS 183 // Various attributes for shared classes. Should be zero for a non-shared class. 184 u2 _shared_class_flags; 185 enum CDSSharedClassFlags { 186 _is_shared_class = 1 << 0, // shadows MetaspaceObj::is_shared 187 _archived_lambda_proxy_is_available = 1 << 1, 188 _has_value_based_class_annotation = 1 << 2, 189 _verified_at_dump_time = 1 << 3, 190 _has_archived_enum_objs = 1 << 4, 191 // This class was not loaded from a classfile in the module image 192 // or classpath. 193 _is_generated_shared_class = 1 << 5 194 }; 195 #endif 196 197 CDS_JAVA_HEAP_ONLY(int _archived_mirror_index;) 198 199 protected: 200 201 Klass(KlassKind kind); 202 Klass(); 203 204 void* operator new(size_t size, ClassLoaderData* loader_data, size_t word_size, TRAPS) throw(); 205 206 public: 207 int kind() { return _kind; } 208 209 enum class DefaultsLookupMode { find, skip }; 210 enum class OverpassLookupMode { find, skip }; 211 enum class StaticLookupMode { find, skip }; 212 enum class PrivateLookupMode { find, skip }; 213 214 virtual bool is_klass() const { return true; } 215 216 // super() cannot be InstanceKlass* -- Java arrays are covariant, and _super is used 217 // to implement that. NB: the _super of "[Ljava/lang/Integer;" is "[Ljava/lang/Number;" 218 // If this is not what your code expects, you're probably looking for Klass::java_super(). 219 Klass* super() const { return _super; } 220 void set_super(Klass* k) { _super = k; } 221 222 // initializes _super link, _primary_supers & _secondary_supers arrays 223 void initialize_supers(Klass* k, Array<InstanceKlass*>* transitive_interfaces, TRAPS); 224 225 // klass-specific helper for initializing _secondary_supers 226 virtual GrowableArray<Klass*>* compute_secondary_supers(int num_extra_slots, 227 Array<InstanceKlass*>* transitive_interfaces); 228 229 // java_super is the Java-level super type as specified by Class.getSuperClass. 230 virtual InstanceKlass* java_super() const { return nullptr; } 231 232 juint super_check_offset() const { return _super_check_offset; } 233 void set_super_check_offset(juint o) { _super_check_offset = o; } 234 235 Klass* secondary_super_cache() const { return _secondary_super_cache; } 236 void set_secondary_super_cache(Klass* k) { _secondary_super_cache = k; } 237 238 Array<Klass*>* secondary_supers() const { return _secondary_supers; } 239 void set_secondary_supers(Array<Klass*>* k); 240 void set_secondary_supers(Array<Klass*>* k, uintx bitmap); 241 242 uint8_t hash_slot() const { return _hash_slot; } 243 244 // Return the element of the _super chain of the given depth. 245 // If there is no such element, return either null or this. 246 Klass* primary_super_of_depth(juint i) const { 247 assert(i < primary_super_limit(), "oob"); 248 Klass* super = _primary_supers[i]; 249 assert(super == nullptr || super->super_depth() == i, "correct display"); 250 return super; 251 } 252 253 // Can this klass be a primary super? False for interfaces and arrays of 254 // interfaces. False also for arrays or classes with long super chains. 255 bool can_be_primary_super() const { 256 const juint secondary_offset = in_bytes(secondary_super_cache_offset()); 257 return super_check_offset() != secondary_offset; 258 } 259 virtual bool can_be_primary_super_slow() const; 260 261 // Returns number of primary supers; may be a number in the inclusive range [0, primary_super_limit]. 262 juint super_depth() const { 263 if (!can_be_primary_super()) { 264 return primary_super_limit(); 265 } else { 266 juint d = (super_check_offset() - in_bytes(primary_supers_offset())) / sizeof(Klass*); 267 assert(d < primary_super_limit(), "oob"); 268 assert(_primary_supers[d] == this, "proper init"); 269 return d; 270 } 271 } 272 273 // java mirror 274 oop java_mirror() const; 275 oop java_mirror_no_keepalive() const; 276 void set_java_mirror(Handle m); 277 278 oop archived_java_mirror() NOT_CDS_JAVA_HEAP_RETURN_(nullptr); 279 void set_archived_java_mirror(int mirror_index) NOT_CDS_JAVA_HEAP_RETURN; 280 281 // Temporary mirror switch used by RedefineClasses 282 OopHandle java_mirror_handle() const { return _java_mirror; } 283 void swap_java_mirror_handle(OopHandle& mirror) { _java_mirror.swap(mirror); } 284 285 // Set java mirror OopHandle to null for CDS 286 // This leaves the OopHandle in the CLD, but that's ok, you can't release them. 287 void clear_java_mirror_handle() { _java_mirror = OopHandle(); } 288 289 // modifier flags 290 jint modifier_flags() const { return _modifier_flags; } 291 void set_modifier_flags(jint flags) { _modifier_flags = flags; } 292 293 // size helper 294 int layout_helper() const { return _layout_helper; } 295 void set_layout_helper(int lh) { _layout_helper = lh; } 296 297 // Note: for instances layout_helper() may include padding. 298 // Use InstanceKlass::contains_field_offset to classify field offsets. 299 300 // sub/superklass links 301 Klass* subklass(bool log = false) const; 302 Klass* next_sibling(bool log = false) const; 303 304 InstanceKlass* superklass() const; 305 void append_to_sibling_list(); // add newly created receiver to superklass' subklass list 306 307 void set_next_link(Klass* k) { _next_link = k; } 308 Klass* next_link() const { return _next_link; } // The next klass defined by the class loader. 309 Klass** next_link_addr() { return &_next_link; } 310 311 // class loader data 312 ClassLoaderData* class_loader_data() const { return _class_loader_data; } 313 void set_class_loader_data(ClassLoaderData* loader_data) { _class_loader_data = loader_data; } 314 315 s2 shared_classpath_index() const { 316 return _shared_class_path_index; 317 }; 318 319 void set_shared_classpath_index(s2 index) { 320 _shared_class_path_index = index; 321 }; 322 323 bool has_archived_mirror_index() const { 324 CDS_JAVA_HEAP_ONLY(return _archived_mirror_index >= 0;) 325 NOT_CDS_JAVA_HEAP(return false); 326 } 327 328 void clear_archived_mirror_index() NOT_CDS_JAVA_HEAP_RETURN; 329 330 void set_lambda_proxy_is_available() { 331 CDS_ONLY(_shared_class_flags |= _archived_lambda_proxy_is_available;) 332 } 333 void clear_lambda_proxy_is_available() { 334 CDS_ONLY(_shared_class_flags &= (u2)(~_archived_lambda_proxy_is_available);) 335 } 336 bool lambda_proxy_is_available() const { 337 CDS_ONLY(return (_shared_class_flags & _archived_lambda_proxy_is_available) != 0;) 338 NOT_CDS(return false;) 339 } 340 341 void set_has_value_based_class_annotation() { 342 CDS_ONLY(_shared_class_flags |= _has_value_based_class_annotation;) 343 } 344 void clear_has_value_based_class_annotation() { 345 CDS_ONLY(_shared_class_flags &= (u2)(~_has_value_based_class_annotation);) 346 } 347 bool has_value_based_class_annotation() const { 348 CDS_ONLY(return (_shared_class_flags & _has_value_based_class_annotation) != 0;) 349 NOT_CDS(return false;) 350 } 351 352 void set_verified_at_dump_time() { 353 CDS_ONLY(_shared_class_flags |= _verified_at_dump_time;) 354 } 355 bool verified_at_dump_time() const { 356 CDS_ONLY(return (_shared_class_flags & _verified_at_dump_time) != 0;) 357 NOT_CDS(return false;) 358 } 359 360 void set_has_archived_enum_objs() { 361 CDS_ONLY(_shared_class_flags |= _has_archived_enum_objs;) 362 } 363 bool has_archived_enum_objs() const { 364 CDS_ONLY(return (_shared_class_flags & _has_archived_enum_objs) != 0;) 365 NOT_CDS(return false;) 366 } 367 368 void set_is_generated_shared_class() { 369 CDS_ONLY(_shared_class_flags |= _is_generated_shared_class;) 370 } 371 bool is_generated_shared_class() const { 372 CDS_ONLY(return (_shared_class_flags & _is_generated_shared_class) != 0;) 373 NOT_CDS(return false;) 374 } 375 376 bool is_shared() const { // shadows MetaspaceObj::is_shared)() 377 CDS_ONLY(return (_shared_class_flags & _is_shared_class) != 0;) 378 NOT_CDS(return false;) 379 } 380 381 void set_is_shared() { 382 CDS_ONLY(_shared_class_flags |= _is_shared_class;) 383 } 384 385 // Obtain the module or package for this class 386 virtual ModuleEntry* module() const = 0; 387 virtual PackageEntry* package() const = 0; 388 389 protected: // internal accessors 390 void set_subklass(Klass* s); 391 void set_next_sibling(Klass* s); 392 393 private: 394 static uint8_t compute_hash_slot(Symbol* s); 395 static void hash_insert(Klass* klass, GrowableArray<Klass*>* secondaries, uintx& bitmap); 396 static uintx hash_secondary_supers(Array<Klass*>* secondaries, bool rewrite); 397 398 public: 399 // Secondary supers table support 400 static Array<Klass*>* pack_secondary_supers(ClassLoaderData* loader_data, 401 GrowableArray<Klass*>* primaries, 402 GrowableArray<Klass*>* secondaries, 403 uintx& bitmap, 404 TRAPS); 405 406 static uintx compute_secondary_supers_bitmap(Array<Klass*>* secondary_supers); 407 static uint8_t compute_home_slot(Klass* k, uintx bitmap); 408 409 static constexpr int SECONDARY_SUPERS_TABLE_SIZE = sizeof(_bitmap) * 8; 410 static constexpr int SECONDARY_SUPERS_TABLE_MASK = SECONDARY_SUPERS_TABLE_SIZE - 1; 411 412 static constexpr uintx SECONDARY_SUPERS_BITMAP_EMPTY = 0; 413 static constexpr uintx SECONDARY_SUPERS_BITMAP_FULL = ~(uintx)0; 414 415 // Compiler support 416 static ByteSize super_offset() { return byte_offset_of(Klass, _super); } 417 static ByteSize super_check_offset_offset() { return byte_offset_of(Klass, _super_check_offset); } 418 static ByteSize primary_supers_offset() { return byte_offset_of(Klass, _primary_supers); } 419 static ByteSize secondary_super_cache_offset() { return byte_offset_of(Klass, _secondary_super_cache); } 420 static ByteSize secondary_supers_offset() { return byte_offset_of(Klass, _secondary_supers); } 421 static ByteSize java_mirror_offset() { return byte_offset_of(Klass, _java_mirror); } 422 static ByteSize class_loader_data_offset() { return byte_offset_of(Klass, _class_loader_data); } 423 static ByteSize modifier_flags_offset() { return byte_offset_of(Klass, _modifier_flags); } 424 static ByteSize layout_helper_offset() { return byte_offset_of(Klass, _layout_helper); } 425 static ByteSize access_flags_offset() { return byte_offset_of(Klass, _access_flags); } 426 #if INCLUDE_JVMCI 427 static ByteSize subklass_offset() { return byte_offset_of(Klass, _subklass); } 428 static ByteSize next_sibling_offset() { return byte_offset_of(Klass, _next_sibling); } 429 #endif 430 static ByteSize bitmap_offset() { return byte_offset_of(Klass, _bitmap); } 431 432 // Unpacking layout_helper: 433 static const int _lh_neutral_value = 0; // neutral non-array non-instance value 434 static const int _lh_instance_slow_path_bit = 0x01; 435 static const int _lh_log2_element_size_shift = BitsPerByte*0; 436 static const int _lh_log2_element_size_mask = BitsPerLong-1; 437 static const int _lh_element_type_shift = BitsPerByte*1; 438 static const int _lh_element_type_mask = right_n_bits(BitsPerByte); // shifted mask 439 static const int _lh_header_size_shift = BitsPerByte*2; 440 static const int _lh_header_size_mask = right_n_bits(BitsPerByte); // shifted mask 441 static const int _lh_array_tag_bits = 2; 442 static const int _lh_array_tag_shift = BitsPerInt - _lh_array_tag_bits; 443 static const int _lh_array_tag_obj_value = ~0x01; // 0x80000000 >> 30 444 445 static const unsigned int _lh_array_tag_type_value = 0Xffffffff; // ~0x00, // 0xC0000000 >> 30 446 447 static int layout_helper_size_in_bytes(jint lh) { 448 assert(lh > (jint)_lh_neutral_value, "must be instance"); 449 return (int) lh & ~_lh_instance_slow_path_bit; 450 } 451 static bool layout_helper_needs_slow_path(jint lh) { 452 assert(lh > (jint)_lh_neutral_value, "must be instance"); 453 return (lh & _lh_instance_slow_path_bit) != 0; 454 } 455 static bool layout_helper_is_instance(jint lh) { 456 return (jint)lh > (jint)_lh_neutral_value; 457 } 458 static bool layout_helper_is_array(jint lh) { 459 return (jint)lh < (jint)_lh_neutral_value; 460 } 461 static bool layout_helper_is_typeArray(jint lh) { 462 // _lh_array_tag_type_value == (lh >> _lh_array_tag_shift); 463 return (juint)lh >= (juint)(_lh_array_tag_type_value << _lh_array_tag_shift); 464 } 465 static bool layout_helper_is_objArray(jint lh) { 466 // _lh_array_tag_obj_value == (lh >> _lh_array_tag_shift); 467 return (jint)lh < (jint)(_lh_array_tag_type_value << _lh_array_tag_shift); 468 } 469 static int layout_helper_header_size(jint lh) { 470 assert(lh < (jint)_lh_neutral_value, "must be array"); 471 int hsize = (lh >> _lh_header_size_shift) & _lh_header_size_mask; 472 assert(hsize > 0 && hsize < (int)sizeof(oopDesc)*3, "sanity"); 473 return hsize; 474 } 475 static BasicType layout_helper_element_type(jint lh) { 476 assert(lh < (jint)_lh_neutral_value, "must be array"); 477 int btvalue = (lh >> _lh_element_type_shift) & _lh_element_type_mask; 478 assert(btvalue >= T_BOOLEAN && btvalue <= T_OBJECT, "sanity"); 479 return (BasicType) btvalue; 480 } 481 482 // Want a pattern to quickly diff against layout header in register 483 // find something less clever! 484 static int layout_helper_boolean_diffbit() { 485 jint zlh = array_layout_helper(T_BOOLEAN); 486 jint blh = array_layout_helper(T_BYTE); 487 assert(zlh != blh, "array layout helpers must differ"); 488 int diffbit = 1; 489 while ((diffbit & (zlh ^ blh)) == 0 && (diffbit & zlh) == 0) { 490 diffbit <<= 1; 491 assert(diffbit != 0, "make sure T_BOOLEAN has a different bit than T_BYTE"); 492 } 493 return diffbit; 494 } 495 496 static int layout_helper_log2_element_size(jint lh) { 497 assert(lh < (jint)_lh_neutral_value, "must be array"); 498 int l2esz = (lh >> _lh_log2_element_size_shift) & _lh_log2_element_size_mask; 499 assert(l2esz <= LogBytesPerLong, 500 "sanity. l2esz: 0x%x for lh: 0x%x", (uint)l2esz, (uint)lh); 501 return l2esz; 502 } 503 static jint array_layout_helper(jint tag, int hsize, BasicType etype, int log2_esize) { 504 return (tag << _lh_array_tag_shift) 505 | (hsize << _lh_header_size_shift) 506 | ((int)etype << _lh_element_type_shift) 507 | (log2_esize << _lh_log2_element_size_shift); 508 } 509 static jint instance_layout_helper(jint size, bool slow_path_flag) { 510 return (size << LogBytesPerWord) 511 | (slow_path_flag ? _lh_instance_slow_path_bit : 0); 512 } 513 static int layout_helper_to_size_helper(jint lh) { 514 assert(lh > (jint)_lh_neutral_value, "must be instance"); 515 // Note that the following expression discards _lh_instance_slow_path_bit. 516 return lh >> LogBytesPerWord; 517 } 518 // Out-of-line version computes everything based on the etype: 519 static jint array_layout_helper(BasicType etype); 520 521 // What is the maximum number of primary superclasses any klass can have? 522 static juint primary_super_limit() { return _primary_super_limit; } 523 524 // vtables 525 klassVtable vtable() const; 526 int vtable_length() const { return _vtable_len; } 527 528 // subclass check 529 bool is_subclass_of(const Klass* k) const; 530 // subtype check: true if is_subclass_of, or if k is interface and receiver implements it 531 bool is_subtype_of(Klass* k) const { 532 juint off = k->super_check_offset(); 533 Klass* sup = *(Klass**)( (address)this + off ); 534 const juint secondary_offset = in_bytes(secondary_super_cache_offset()); 535 if (sup == k) { 536 return true; 537 } else if (off != secondary_offset) { 538 return false; 539 } else { 540 return search_secondary_supers(k); 541 } 542 } 543 544 bool search_secondary_supers(Klass* k) const; 545 546 // Find LCA in class hierarchy 547 Klass *LCA( Klass *k ); 548 549 // Check whether reflection/jni/jvm code is allowed to instantiate this class; 550 // if not, throw either an Error or an Exception. 551 virtual void check_valid_for_instantiation(bool throwError, TRAPS); 552 553 // array copying 554 virtual void copy_array(arrayOop s, int src_pos, arrayOop d, int dst_pos, int length, TRAPS); 555 556 // tells if the class should be initialized 557 virtual bool should_be_initialized() const { return false; } 558 // initializes the klass 559 virtual void initialize(TRAPS); 560 virtual Klass* find_field(Symbol* name, Symbol* signature, fieldDescriptor* fd) const; 561 virtual Method* uncached_lookup_method(const Symbol* name, const Symbol* signature, 562 OverpassLookupMode overpass_mode, 563 PrivateLookupMode = PrivateLookupMode::find) const; 564 public: 565 Method* lookup_method(const Symbol* name, const Symbol* signature) const { 566 return uncached_lookup_method(name, signature, OverpassLookupMode::find); 567 } 568 569 // array class with specific rank 570 virtual ArrayKlass* array_klass(int rank, TRAPS) = 0; 571 572 // array class with this klass as element type 573 virtual ArrayKlass* array_klass(TRAPS) = 0; 574 575 // These will return null instead of allocating on the heap: 576 virtual ArrayKlass* array_klass_or_null(int rank) = 0; 577 virtual ArrayKlass* array_klass_or_null() = 0; 578 579 virtual oop protection_domain() const = 0; 580 581 oop class_loader() const; 582 583 inline oop klass_holder() const; 584 585 protected: 586 587 // Error handling when length > max_length or length < 0 588 static void check_array_allocation_length(int length, int max_length, TRAPS); 589 590 void set_vtable_length(int len) { _vtable_len= len; } 591 592 vtableEntry* start_of_vtable() const; 593 #if INCLUDE_CDS 594 void restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS); 595 #endif 596 public: 597 Method* method_at_vtable(int index); 598 599 static ByteSize vtable_start_offset(); 600 static ByteSize vtable_length_offset() { 601 return byte_offset_of(Klass, _vtable_len); 602 } 603 604 #if INCLUDE_CDS 605 // CDS support - remove and restore oops from metadata. Oops are not shared. 606 virtual void remove_unshareable_info(); 607 virtual void remove_java_mirror(); 608 609 bool is_unshareable_info_restored() const { 610 assert(is_shared(), "use this for shared classes only"); 611 if (has_archived_mirror_index()) { 612 // _java_mirror is not a valid OopHandle but rather an encoded reference in the shared heap 613 return false; 614 } else if (_java_mirror.is_empty()) { 615 return false; 616 } else { 617 return true; 618 } 619 } 620 #endif // INCLUDE_CDS 621 622 public: 623 // ALL FUNCTIONS BELOW THIS POINT ARE DISPATCHED FROM AN OOP 624 // These functions describe behavior for the oop not the KLASS. 625 626 // actual oop size of obj in memory in word size. 627 virtual size_t oop_size(oop obj) const = 0; 628 629 // Size of klass in word size. 630 virtual int size() const = 0; 631 632 // Returns the Java name for a class (Resource allocated) 633 // For arrays, this returns the name of the element with a leading '['. 634 // For classes, this returns the name with the package separators 635 // turned into '.'s. 636 const char* external_name() const; 637 // Returns the name for a class (Resource allocated) as the class 638 // would appear in a signature. 639 // For arrays, this returns the name of the element with a leading '['. 640 // For classes, this returns the name with a leading 'L' and a trailing ';' 641 // and the package separators as '/'. 642 virtual const char* signature_name() const; 643 644 const char* joint_in_module_of_loader(const Klass* class2, bool include_parent_loader = false) const; 645 const char* class_in_module_of_loader(bool use_are = false, bool include_parent_loader = false) const; 646 647 // Returns "interface", "abstract class" or "class". 648 const char* external_kind() const; 649 650 // type testing operations 651 #ifdef ASSERT 652 protected: 653 virtual bool is_instance_klass_slow() const { return false; } 654 virtual bool is_array_klass_slow() const { return false; } 655 virtual bool is_objArray_klass_slow() const { return false; } 656 virtual bool is_typeArray_klass_slow() const { return false; } 657 #endif // ASSERT 658 public: 659 660 // Fast non-virtual versions 661 #ifndef ASSERT 662 #define assert_same_query(xval, xcheck) xval 663 #else 664 private: 665 static bool assert_same_query(bool xval, bool xslow) { 666 assert(xval == xslow, "slow and fast queries agree"); 667 return xval; 668 } 669 public: 670 #endif 671 672 bool is_instance_klass() const { return assert_same_query(_kind <= InstanceStackChunkKlassKind, is_instance_klass_slow()); } 673 // Other is anything that is not one of the more specialized kinds of InstanceKlass. 674 bool is_other_instance_klass() const { return _kind == InstanceKlassKind; } 675 bool is_reference_instance_klass() const { return _kind == InstanceRefKlassKind; } 676 bool is_mirror_instance_klass() const { return _kind == InstanceMirrorKlassKind; } 677 bool is_class_loader_instance_klass() const { return _kind == InstanceClassLoaderKlassKind; } 678 bool is_array_klass() const { return assert_same_query( _kind >= TypeArrayKlassKind, is_array_klass_slow()); } 679 bool is_stack_chunk_instance_klass() const { return _kind == InstanceStackChunkKlassKind; } 680 bool is_objArray_klass() const { return assert_same_query( _kind == ObjArrayKlassKind, is_objArray_klass_slow()); } 681 bool is_typeArray_klass() const { return assert_same_query( _kind == TypeArrayKlassKind, is_typeArray_klass_slow()); } 682 #undef assert_same_query 683 684 // Access flags 685 AccessFlags access_flags() const { return _access_flags; } 686 void set_access_flags(AccessFlags flags) { _access_flags = flags; } 687 688 bool is_public() const { return _access_flags.is_public(); } 689 bool is_final() const { return _access_flags.is_final(); } 690 bool is_interface() const { return _access_flags.is_interface(); } 691 bool is_abstract() const { return _access_flags.is_abstract(); } 692 bool is_super() const { return _access_flags.is_super(); } 693 bool is_synthetic() const { return _access_flags.is_synthetic(); } 694 void set_is_synthetic() { _access_flags.set_is_synthetic(); } 695 bool has_finalizer() const { return _access_flags.has_finalizer(); } 696 void set_has_finalizer() { _access_flags.set_has_finalizer(); } 697 bool is_hidden() const { return access_flags().is_hidden_class(); } 698 void set_is_hidden() { _access_flags.set_is_hidden_class(); } 699 bool is_value_based() { return _access_flags.is_value_based_class(); } 700 void set_is_value_based() { _access_flags.set_is_value_based_class(); } 701 702 inline bool is_non_strong_hidden() const; 703 704 bool is_cloneable() const; 705 void set_is_cloneable(); 706 707 JFR_ONLY(DEFINE_TRACE_ID_METHODS;) 708 709 virtual void metaspace_pointers_do(MetaspaceClosure* iter); 710 virtual MetaspaceObj::Type type() const { return ClassType; } 711 712 inline bool is_loader_alive() const; 713 714 void clean_subklass(); 715 716 static void clean_weak_klass_links(bool unloading_occurred, bool clean_alive_klasses = true); 717 static void clean_subklass_tree() { 718 clean_weak_klass_links(/*unloading_occurred*/ true , /* clean_alive_klasses */ false); 719 } 720 721 // Return self, except for abstract classes with exactly 1 722 // implementor. Then return the 1 concrete implementation. 723 Klass *up_cast_abstract(); 724 725 // klass name 726 Symbol* name() const { return _name; } 727 void set_name(Symbol* n); 728 729 virtual void release_C_heap_structures(bool release_constant_pool = true); 730 731 public: 732 virtual jint compute_modifier_flags() const = 0; 733 734 // JVMTI support 735 virtual jint jvmti_class_status() const; 736 737 // Printing 738 virtual void print_on(outputStream* st) const; 739 740 virtual void oop_print_value_on(oop obj, outputStream* st); 741 virtual void oop_print_on (oop obj, outputStream* st); 742 743 void print_secondary_supers_on(outputStream* st) const; 744 745 virtual const char* internal_name() const = 0; 746 747 // Verification 748 virtual void verify_on(outputStream* st); 749 void verify() { verify_on(tty); } 750 751 #ifndef PRODUCT 752 bool verify_vtable_index(int index); 753 #endif 754 755 virtual void oop_verify_on(oop obj, outputStream* st); 756 757 // for error reporting 758 static bool is_valid(Klass* k); 759 760 static void on_secondary_supers_verification_failure(Klass* super, Klass* sub, bool linear_result, bool table_result, const char* msg); 761 }; 762 763 #endif // SHARE_OOPS_KLASS_HPP