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/klassFlags.hpp" 31 #include "oops/markWord.hpp" 32 #include "oops/metadata.hpp" 33 #include "oops/oop.hpp" 34 #include "oops/oopHandle.hpp" 35 #include "utilities/accessFlags.hpp" 36 #include "utilities/macros.hpp" 37 #if INCLUDE_JFR 38 #include "jfr/support/jfrTraceIdExtension.hpp" 39 #endif 40 41 // 42 // A Klass provides: 43 // 1: language level class object (method dictionary etc.) 44 // 2: provide vm dispatch behavior for the object 45 // Both functions are combined into one C++ class. 46 47 // One reason for the oop/klass dichotomy in the implementation is 48 // that we don't want a C++ vtbl pointer in every object. Thus, 49 // normal oops don't have any virtual functions. Instead, they 50 // forward all "virtual" functions to their klass, which does have 51 // a vtbl and does the C++ dispatch depending on the object's 52 // actual type. (See oop.inline.hpp for some of the forwarding code.) 53 // ALL FUNCTIONS IMPLEMENTING THIS DISPATCH ARE PREFIXED WITH "oop_"! 54 55 // Forward declarations. 56 template <class T> class Array; 57 template <class T> class GrowableArray; 58 class ClassLoaderData; 59 class fieldDescriptor; 60 class klassVtable; 61 class ModuleEntry; 62 class PackageEntry; 63 class ParCompactionManager; 64 class PSPromotionManager; 65 class vtableEntry; 66 67 class Klass : public Metadata { 68 friend class VMStructs; 69 friend class JVMCIVMStructs; 70 public: 71 // Klass Kinds for all subclasses of Klass 72 enum KlassKind { 73 InstanceKlassKind, 74 InstanceRefKlassKind, 75 InstanceMirrorKlassKind, 76 InstanceClassLoaderKlassKind, 77 InstanceStackChunkKlassKind, 78 TypeArrayKlassKind, 79 ObjArrayKlassKind, 80 UnknownKlassKind 81 }; 82 83 static const uint KLASS_KIND_COUNT = ObjArrayKlassKind + 1; 84 protected: 85 86 // If you add a new field that points to any metaspace object, you 87 // must add this field to Klass::metaspace_pointers_do(). 88 89 // note: put frequently-used fields together at start of klass structure 90 // for better cache behavior (may not make much of a difference but sure won't hurt) 91 enum { _primary_super_limit = 8 }; 92 93 // The "layout helper" is a combined descriptor of object layout. 94 // For klasses which are neither instance nor array, the value is zero. 95 // 96 // For instances, layout helper is a positive number, the instance size. 97 // This size is already passed through align_object_size and scaled to bytes. 98 // The low order bit is set if instances of this class cannot be 99 // allocated using the fastpath. 100 // 101 // For arrays, layout helper is a negative number, containing four 102 // distinct bytes, as follows: 103 // MSB:[tag, hsz, ebt, log2(esz)]:LSB 104 // where: 105 // tag is 0x80 if the elements are oops, 0xC0 if non-oops 106 // hsz is array header size in bytes (i.e., offset of first element) 107 // ebt is the BasicType of the elements 108 // esz is the element size in bytes 109 // This packed word is arranged so as to be quickly unpacked by the 110 // various fast paths that use the various subfields. 111 // 112 // The esz bits can be used directly by a SLL instruction, without masking. 113 // 114 // Note that the array-kind tag looks like 0x00 for instance klasses, 115 // since their length in bytes is always less than 24Mb. 116 // 117 // Final note: This comes first, immediately after C++ vtable, 118 // because it is frequently queried. 119 jint _layout_helper; 120 121 // Klass kind used to resolve the runtime type of the instance. 122 // - Used to implement devirtualized oop closure dispatching. 123 // - Various type checking in the JVM 124 const KlassKind _kind; 125 126 // Processed access flags, for use by Class.getModifiers. 127 jint _modifier_flags; 128 129 // The fields _super_check_offset, _secondary_super_cache, _secondary_supers 130 // and _primary_supers all help make fast subtype checks. See big discussion 131 // in doc/server_compiler/checktype.txt 132 // 133 // Where to look to observe a supertype (it is &_secondary_super_cache for 134 // secondary supers, else is &_primary_supers[depth()]. 135 juint _super_check_offset; 136 137 // Class name. Instance classes: java/lang/String, etc. Array classes: [I, 138 // [Ljava/lang/String;, etc. Set to zero for all other kinds of classes. 139 Symbol* _name; 140 141 // Cache of last observed secondary supertype 142 Klass* _secondary_super_cache; 143 // Array of all secondary supertypes 144 Array<Klass*>* _secondary_supers; 145 // Ordered list of all primary supertypes 146 Klass* _primary_supers[_primary_super_limit]; 147 // java/lang/Class instance mirroring this class 148 OopHandle _java_mirror; 149 // Superclass 150 Klass* _super; 151 // First subclass (null if none); _subklass->next_sibling() is next one 152 Klass* volatile _subklass; 153 // Sibling link (or null); links all subklasses of a klass 154 Klass* volatile _next_sibling; 155 156 // All klasses loaded by a class loader are chained through these links 157 Klass* _next_link; 158 159 // The VM's representation of the ClassLoader used to load this class. 160 // Provide access the corresponding instance java.lang.ClassLoader. 161 ClassLoaderData* _class_loader_data; 162 163 164 int _vtable_len; // vtable length. This field may be read very often when we 165 // have lots of itable dispatches (e.g., lambdas and streams). 166 // Keep it away from the beginning of a Klass to avoid cacheline 167 // contention that may happen when a nearby object is modified. 168 AccessFlags _access_flags; // Access flags. The class/interface distinction is stored here. 169 // Some flags created by the JVM, not in the class file itself, 170 // are in _misc_flags below. 171 172 JFR_ONLY(DEFINE_TRACE_ID_FIELD;) 173 174 // Bitmap and hash code used by hashed secondary supers. 175 uintx _bitmap; 176 uint8_t _hash_slot; 177 178 private: 179 // This is an index into FileMapHeader::_shared_path_table[], to 180 // associate this class with the JAR file where it's loaded from during 181 // dump time. If a class is not loaded from the shared archive, this field is 182 // -1. 183 s2 _shared_class_path_index; 184 185 #if INCLUDE_CDS 186 // Various attributes for shared classes. Should be zero for a non-shared class. 187 u2 _shared_class_flags; 188 enum CDSSharedClassFlags { 189 _is_shared_class = 1 << 0, // shadows MetaspaceObj::is_shared 190 _archived_lambda_proxy_is_available = 1 << 1, 191 _has_value_based_class_annotation = 1 << 2, 192 _verified_at_dump_time = 1 << 3, 193 _has_archived_enum_objs = 1 << 4, 194 // This class was not loaded from a classfile in the module image 195 // or classpath. 196 _is_generated_shared_class = 1 << 5, 197 // The archived mirror is already initialized. No need to call <clinit> 198 _has_preinitialized_mirror = 1 << 6, 199 }; 200 #endif 201 202 KlassFlags _misc_flags; 203 204 CDS_JAVA_HEAP_ONLY(int _archived_mirror_index;) 205 206 protected: 207 208 Klass(KlassKind kind); 209 Klass(); 210 211 public: 212 int kind() { return _kind; } 213 214 enum class DefaultsLookupMode { find, skip }; 215 enum class OverpassLookupMode { find, skip }; 216 enum class StaticLookupMode { find, skip }; 217 enum class PrivateLookupMode { find, skip }; 218 219 virtual bool is_klass() const { return true; } 220 221 // super() cannot be InstanceKlass* -- Java arrays are covariant, and _super is used 222 // to implement that. NB: the _super of "[Ljava/lang/Integer;" is "[Ljava/lang/Number;" 223 // If this is not what your code expects, you're probably looking for Klass::java_super(). 224 Klass* super() const { return _super; } 225 void set_super(Klass* k) { _super = k; } 226 227 // initializes _super link, _primary_supers & _secondary_supers arrays 228 void initialize_supers(Klass* k, Array<InstanceKlass*>* transitive_interfaces, TRAPS); 229 230 // klass-specific helper for initializing _secondary_supers 231 virtual GrowableArray<Klass*>* compute_secondary_supers(int num_extra_slots, 232 Array<InstanceKlass*>* transitive_interfaces); 233 234 // java_super is the Java-level super type as specified by Class.getSuperClass. 235 virtual InstanceKlass* java_super() const { return nullptr; } 236 237 juint super_check_offset() const { return _super_check_offset; } 238 void set_super_check_offset(juint o) { _super_check_offset = o; } 239 240 Klass* secondary_super_cache() const { return _secondary_super_cache; } 241 void set_secondary_super_cache(Klass* k) { _secondary_super_cache = k; } 242 243 Array<Klass*>* secondary_supers() const { return _secondary_supers; } 244 void set_secondary_supers(Array<Klass*>* k); 245 void set_secondary_supers(Array<Klass*>* k, uintx bitmap); 246 247 uint8_t hash_slot() const { return _hash_slot; } 248 249 // Return the element of the _super chain of the given depth. 250 // If there is no such element, return either null or this. 251 Klass* primary_super_of_depth(juint i) const { 252 assert(i < primary_super_limit(), "oob"); 253 Klass* super = _primary_supers[i]; 254 assert(super == nullptr || super->super_depth() == i, "correct display"); 255 return super; 256 } 257 258 // Can this klass be a primary super? False for interfaces and arrays of 259 // interfaces. False also for arrays or classes with long super chains. 260 bool can_be_primary_super() const { 261 const juint secondary_offset = in_bytes(secondary_super_cache_offset()); 262 return super_check_offset() != secondary_offset; 263 } 264 virtual bool can_be_primary_super_slow() const; 265 266 // Returns number of primary supers; may be a number in the inclusive range [0, primary_super_limit]. 267 juint super_depth() const { 268 if (!can_be_primary_super()) { 269 return primary_super_limit(); 270 } else { 271 juint d = (super_check_offset() - in_bytes(primary_supers_offset())) / sizeof(Klass*); 272 assert(d < primary_super_limit(), "oob"); 273 assert(_primary_supers[d] == this, "proper init"); 274 return d; 275 } 276 } 277 278 // java mirror 279 oop java_mirror() const; 280 oop java_mirror_no_keepalive() const; 281 void set_java_mirror(Handle m); 282 283 oop archived_java_mirror() NOT_CDS_JAVA_HEAP_RETURN_(nullptr); 284 void set_archived_java_mirror(int mirror_index) NOT_CDS_JAVA_HEAP_RETURN; 285 286 // Temporary mirror switch used by RedefineClasses 287 OopHandle java_mirror_handle() const { return _java_mirror; } 288 void swap_java_mirror_handle(OopHandle& mirror) { _java_mirror.swap(mirror); } 289 290 // Set java mirror OopHandle to null for CDS 291 // This leaves the OopHandle in the CLD, but that's ok, you can't release them. 292 void clear_java_mirror_handle() { _java_mirror = OopHandle(); } 293 294 // modifier flags 295 jint modifier_flags() const { return _modifier_flags; } 296 void set_modifier_flags(jint flags) { _modifier_flags = flags; } 297 298 // size helper 299 int layout_helper() const { return _layout_helper; } 300 void set_layout_helper(int lh) { _layout_helper = lh; } 301 302 // Note: for instances layout_helper() may include padding. 303 // Use InstanceKlass::contains_field_offset to classify field offsets. 304 305 // sub/superklass links 306 Klass* subklass(bool log = false) const; 307 Klass* next_sibling(bool log = false) const; 308 309 InstanceKlass* superklass() const; 310 void append_to_sibling_list(); // add newly created receiver to superklass' subklass list 311 312 void set_next_link(Klass* k) { _next_link = k; } 313 Klass* next_link() const { return _next_link; } // The next klass defined by the class loader. 314 Klass** next_link_addr() { return &_next_link; } 315 316 // class loader data 317 ClassLoaderData* class_loader_data() const { return _class_loader_data; } 318 void set_class_loader_data(ClassLoaderData* loader_data) { _class_loader_data = loader_data; } 319 320 s2 shared_classpath_index() const { 321 return _shared_class_path_index; 322 }; 323 324 void set_shared_classpath_index(s2 index) { 325 _shared_class_path_index = index; 326 }; 327 328 bool has_archived_mirror_index() const { 329 CDS_JAVA_HEAP_ONLY(return _archived_mirror_index >= 0;) 330 NOT_CDS_JAVA_HEAP(return false); 331 } 332 333 void clear_archived_mirror_index() NOT_CDS_JAVA_HEAP_RETURN; 334 335 void set_lambda_proxy_is_available() { 336 CDS_ONLY(_shared_class_flags |= _archived_lambda_proxy_is_available;) 337 } 338 void clear_lambda_proxy_is_available() { 339 CDS_ONLY(_shared_class_flags &= (u2)(~_archived_lambda_proxy_is_available);) 340 } 341 bool lambda_proxy_is_available() const { 342 CDS_ONLY(return (_shared_class_flags & _archived_lambda_proxy_is_available) != 0;) 343 NOT_CDS(return false;) 344 } 345 346 void set_has_value_based_class_annotation() { 347 CDS_ONLY(_shared_class_flags |= _has_value_based_class_annotation;) 348 } 349 void clear_has_value_based_class_annotation() { 350 CDS_ONLY(_shared_class_flags &= (u2)(~_has_value_based_class_annotation);) 351 } 352 bool has_value_based_class_annotation() const { 353 CDS_ONLY(return (_shared_class_flags & _has_value_based_class_annotation) != 0;) 354 NOT_CDS(return false;) 355 } 356 357 void set_verified_at_dump_time() { 358 CDS_ONLY(_shared_class_flags |= _verified_at_dump_time;) 359 } 360 bool verified_at_dump_time() const { 361 CDS_ONLY(return (_shared_class_flags & _verified_at_dump_time) != 0;) 362 NOT_CDS(return false;) 363 } 364 365 void set_has_archived_enum_objs() { 366 CDS_ONLY(_shared_class_flags |= _has_archived_enum_objs;) 367 } 368 bool has_archived_enum_objs() const { 369 CDS_ONLY(return (_shared_class_flags & _has_archived_enum_objs) != 0;) 370 NOT_CDS(return false;) 371 } 372 373 void set_is_generated_shared_class() { 374 CDS_ONLY(_shared_class_flags |= _is_generated_shared_class;) 375 } 376 bool is_generated_shared_class() const { 377 CDS_ONLY(return (_shared_class_flags & _is_generated_shared_class) != 0;) 378 NOT_CDS(return false;) 379 } 380 381 void set_has_preinitialized_mirror() { 382 CDS_ONLY(_shared_class_flags |= _has_preinitialized_mirror;) 383 } 384 bool has_preinitialized_mirror() const { 385 CDS_ONLY(return (_shared_class_flags & _has_preinitialized_mirror) != 0;) 386 NOT_CDS(return false;) 387 } 388 389 bool is_shared() const { // shadows MetaspaceObj::is_shared)() 390 CDS_ONLY(return (_shared_class_flags & _is_shared_class) != 0;) 391 NOT_CDS(return false;) 392 } 393 394 void set_is_shared() { 395 CDS_ONLY(_shared_class_flags |= _is_shared_class;) 396 } 397 398 // Obtain the module or package for this class 399 virtual ModuleEntry* module() const = 0; 400 virtual PackageEntry* package() const = 0; 401 402 protected: // internal accessors 403 void set_subklass(Klass* s); 404 void set_next_sibling(Klass* s); 405 406 private: 407 static uint8_t compute_hash_slot(Symbol* s); 408 static void hash_insert(Klass* klass, GrowableArray<Klass*>* secondaries, uintx& bitmap); 409 static uintx hash_secondary_supers(Array<Klass*>* secondaries, bool rewrite); 410 411 public: 412 // Secondary supers table support 413 static Array<Klass*>* pack_secondary_supers(ClassLoaderData* loader_data, 414 GrowableArray<Klass*>* primaries, 415 GrowableArray<Klass*>* secondaries, 416 uintx& bitmap, 417 TRAPS); 418 419 static uintx compute_secondary_supers_bitmap(Array<Klass*>* secondary_supers); 420 static uint8_t compute_home_slot(Klass* k, uintx bitmap); 421 422 static constexpr int SECONDARY_SUPERS_TABLE_SIZE = sizeof(_bitmap) * 8; 423 static constexpr int SECONDARY_SUPERS_TABLE_MASK = SECONDARY_SUPERS_TABLE_SIZE - 1; 424 425 static constexpr uintx SECONDARY_SUPERS_BITMAP_EMPTY = 0; 426 static constexpr uintx SECONDARY_SUPERS_BITMAP_FULL = ~(uintx)0; 427 428 // Compiler support 429 static ByteSize super_offset() { return byte_offset_of(Klass, _super); } 430 static ByteSize super_check_offset_offset() { return byte_offset_of(Klass, _super_check_offset); } 431 static ByteSize primary_supers_offset() { return byte_offset_of(Klass, _primary_supers); } 432 static ByteSize secondary_super_cache_offset() { return byte_offset_of(Klass, _secondary_super_cache); } 433 static ByteSize secondary_supers_offset() { return byte_offset_of(Klass, _secondary_supers); } 434 static ByteSize java_mirror_offset() { return byte_offset_of(Klass, _java_mirror); } 435 static ByteSize class_loader_data_offset() { return byte_offset_of(Klass, _class_loader_data); } 436 static ByteSize modifier_flags_offset() { return byte_offset_of(Klass, _modifier_flags); } 437 static ByteSize layout_helper_offset() { return byte_offset_of(Klass, _layout_helper); } 438 static ByteSize access_flags_offset() { return byte_offset_of(Klass, _access_flags); } 439 #if INCLUDE_JVMCI 440 static ByteSize subklass_offset() { return byte_offset_of(Klass, _subklass); } 441 static ByteSize next_sibling_offset() { return byte_offset_of(Klass, _next_sibling); } 442 #endif 443 static ByteSize bitmap_offset() { return byte_offset_of(Klass, _bitmap); } 444 static ByteSize misc_flags_offset() { return byte_offset_of(Klass, _misc_flags._flags); } 445 446 // Unpacking layout_helper: 447 static const int _lh_neutral_value = 0; // neutral non-array non-instance value 448 static const int _lh_instance_slow_path_bit = 0x01; 449 static const int _lh_log2_element_size_shift = BitsPerByte*0; 450 static const int _lh_log2_element_size_mask = BitsPerLong-1; 451 static const int _lh_element_type_shift = BitsPerByte*1; 452 static const int _lh_element_type_mask = right_n_bits(BitsPerByte); // shifted mask 453 static const int _lh_header_size_shift = BitsPerByte*2; 454 static const int _lh_header_size_mask = right_n_bits(BitsPerByte); // shifted mask 455 static const int _lh_array_tag_bits = 2; 456 static const int _lh_array_tag_shift = BitsPerInt - _lh_array_tag_bits; 457 static const int _lh_array_tag_obj_value = ~0x01; // 0x80000000 >> 30 458 459 static const unsigned int _lh_array_tag_type_value = 0Xffffffff; // ~0x00, // 0xC0000000 >> 30 460 461 static int layout_helper_size_in_bytes(jint lh) { 462 assert(lh > (jint)_lh_neutral_value, "must be instance"); 463 return (int) lh & ~_lh_instance_slow_path_bit; 464 } 465 static bool layout_helper_needs_slow_path(jint lh) { 466 assert(lh > (jint)_lh_neutral_value, "must be instance"); 467 return (lh & _lh_instance_slow_path_bit) != 0; 468 } 469 static bool layout_helper_is_instance(jint lh) { 470 return (jint)lh > (jint)_lh_neutral_value; 471 } 472 static bool layout_helper_is_array(jint lh) { 473 return (jint)lh < (jint)_lh_neutral_value; 474 } 475 static bool layout_helper_is_typeArray(jint lh) { 476 // _lh_array_tag_type_value == (lh >> _lh_array_tag_shift); 477 return (juint)lh >= (juint)(_lh_array_tag_type_value << _lh_array_tag_shift); 478 } 479 static bool layout_helper_is_objArray(jint lh) { 480 // _lh_array_tag_obj_value == (lh >> _lh_array_tag_shift); 481 return (jint)lh < (jint)(_lh_array_tag_type_value << _lh_array_tag_shift); 482 } 483 static int layout_helper_header_size(jint lh) { 484 assert(lh < (jint)_lh_neutral_value, "must be array"); 485 int hsize = (lh >> _lh_header_size_shift) & _lh_header_size_mask; 486 assert(hsize > 0 && hsize < (int)sizeof(oopDesc)*3, "sanity"); 487 return hsize; 488 } 489 static BasicType layout_helper_element_type(jint lh) { 490 assert(lh < (jint)_lh_neutral_value, "must be array"); 491 int btvalue = (lh >> _lh_element_type_shift) & _lh_element_type_mask; 492 assert(btvalue >= T_BOOLEAN && btvalue <= T_OBJECT, "sanity"); 493 return (BasicType) btvalue; 494 } 495 496 // Want a pattern to quickly diff against layout header in register 497 // find something less clever! 498 static int layout_helper_boolean_diffbit() { 499 jint zlh = array_layout_helper(T_BOOLEAN); 500 jint blh = array_layout_helper(T_BYTE); 501 assert(zlh != blh, "array layout helpers must differ"); 502 int diffbit = 1; 503 while ((diffbit & (zlh ^ blh)) == 0 && (diffbit & zlh) == 0) { 504 diffbit <<= 1; 505 assert(diffbit != 0, "make sure T_BOOLEAN has a different bit than T_BYTE"); 506 } 507 return diffbit; 508 } 509 510 static int layout_helper_log2_element_size(jint lh) { 511 assert(lh < (jint)_lh_neutral_value, "must be array"); 512 int l2esz = (lh >> _lh_log2_element_size_shift) & _lh_log2_element_size_mask; 513 assert(l2esz <= LogBytesPerLong, 514 "sanity. l2esz: 0x%x for lh: 0x%x", (uint)l2esz, (uint)lh); 515 return l2esz; 516 } 517 static jint array_layout_helper(jint tag, int hsize, BasicType etype, int log2_esize) { 518 return (tag << _lh_array_tag_shift) 519 | (hsize << _lh_header_size_shift) 520 | ((int)etype << _lh_element_type_shift) 521 | (log2_esize << _lh_log2_element_size_shift); 522 } 523 static jint instance_layout_helper(jint size, bool slow_path_flag) { 524 return (size << LogBytesPerWord) 525 | (slow_path_flag ? _lh_instance_slow_path_bit : 0); 526 } 527 static int layout_helper_to_size_helper(jint lh) { 528 assert(lh > (jint)_lh_neutral_value, "must be instance"); 529 // Note that the following expression discards _lh_instance_slow_path_bit. 530 return lh >> LogBytesPerWord; 531 } 532 // Out-of-line version computes everything based on the etype: 533 static jint array_layout_helper(BasicType etype); 534 535 // What is the maximum number of primary superclasses any klass can have? 536 static juint primary_super_limit() { return _primary_super_limit; } 537 538 // vtables 539 klassVtable vtable() const; 540 int vtable_length() const { return _vtable_len; } 541 542 // subclass check 543 bool is_subclass_of(const Klass* k) const; 544 // subtype check: true if is_subclass_of, or if k is interface and receiver implements it 545 bool is_subtype_of(Klass* k) const { 546 juint off = k->super_check_offset(); 547 Klass* sup = *(Klass**)( (address)this + off ); 548 const juint secondary_offset = in_bytes(secondary_super_cache_offset()); 549 if (sup == k) { 550 return true; 551 } else if (off != secondary_offset) { 552 return false; 553 } else { 554 return search_secondary_supers(k); 555 } 556 } 557 558 bool search_secondary_supers(Klass* k) const; 559 560 // Find LCA in class hierarchy 561 Klass *LCA( Klass *k ); 562 563 // Check whether reflection/jni/jvm code is allowed to instantiate this class; 564 // if not, throw either an Error or an Exception. 565 virtual void check_valid_for_instantiation(bool throwError, TRAPS); 566 567 // array copying 568 virtual void copy_array(arrayOop s, int src_pos, arrayOop d, int dst_pos, int length, TRAPS); 569 570 // tells if the class should be initialized 571 virtual bool should_be_initialized() const { return false; } 572 // initializes the klass 573 virtual void initialize(TRAPS); 574 virtual Klass* find_field(Symbol* name, Symbol* signature, fieldDescriptor* fd) const; 575 virtual Method* uncached_lookup_method(const Symbol* name, const Symbol* signature, 576 OverpassLookupMode overpass_mode, 577 PrivateLookupMode = PrivateLookupMode::find) const; 578 public: 579 Method* lookup_method(const Symbol* name, const Symbol* signature) const { 580 return uncached_lookup_method(name, signature, OverpassLookupMode::find); 581 } 582 583 // array class with specific rank 584 virtual ArrayKlass* array_klass(int rank, TRAPS) = 0; 585 586 // array class with this klass as element type 587 virtual ArrayKlass* array_klass(TRAPS) = 0; 588 589 // These will return null instead of allocating on the heap: 590 virtual ArrayKlass* array_klass_or_null(int rank) = 0; 591 virtual ArrayKlass* array_klass_or_null() = 0; 592 593 virtual oop protection_domain() const = 0; 594 595 oop class_loader() const; 596 Symbol* class_loader_name_and_id() const; 597 598 inline oop klass_holder() const; 599 600 protected: 601 602 // Error handling when length > max_length or length < 0 603 static void check_array_allocation_length(int length, int max_length, TRAPS); 604 605 void set_vtable_length(int len) { _vtable_len= len; } 606 607 vtableEntry* start_of_vtable() const; 608 #if INCLUDE_CDS 609 void restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS); 610 #endif 611 public: 612 Method* method_at_vtable(int index); 613 614 static ByteSize vtable_start_offset(); 615 static ByteSize vtable_length_offset() { 616 return byte_offset_of(Klass, _vtable_len); 617 } 618 619 #if INCLUDE_CDS 620 // CDS support - remove and restore oops from metadata. Oops are not shared. 621 virtual void remove_unshareable_info(); 622 virtual void remove_java_mirror(); 623 624 bool is_unshareable_info_restored() const { 625 assert(is_shared(), "use this for shared classes only"); 626 if (has_archived_mirror_index()) { 627 // _java_mirror is not a valid OopHandle but rather an encoded reference in the shared heap 628 return false; 629 } else if (_java_mirror.is_empty()) { 630 return false; 631 } else { 632 return true; 633 } 634 } 635 #endif // INCLUDE_CDS 636 637 public: 638 // ALL FUNCTIONS BELOW THIS POINT ARE DISPATCHED FROM AN OOP 639 // These functions describe behavior for the oop not the KLASS. 640 641 // actual oop size of obj in memory in word size. 642 virtual size_t oop_size(oop obj) const = 0; 643 644 // Size of klass in word size. 645 virtual int size() const = 0; 646 647 // Returns the Java name for a class (Resource allocated) 648 // For arrays, this returns the name of the element with a leading '['. 649 // For classes, this returns the name with the package separators 650 // turned into '.'s. 651 const char* external_name() const; 652 // Returns the name for a class (Resource allocated) as the class 653 // would appear in a signature. 654 // For arrays, this returns the name of the element with a leading '['. 655 // For classes, this returns the name with a leading 'L' and a trailing ';' 656 // and the package separators as '/'. 657 virtual const char* signature_name() const; 658 659 const char* joint_in_module_of_loader(const Klass* class2, bool include_parent_loader = false) const; 660 const char* class_in_module_of_loader(bool use_are = false, bool include_parent_loader = false) const; 661 662 // Returns "interface", "abstract class" or "class". 663 const char* external_kind() const; 664 665 // type testing operations 666 #ifdef ASSERT 667 protected: 668 virtual bool is_instance_klass_slow() const { return false; } 669 virtual bool is_array_klass_slow() const { return false; } 670 virtual bool is_objArray_klass_slow() const { return false; } 671 virtual bool is_typeArray_klass_slow() const { return false; } 672 #endif // ASSERT 673 public: 674 675 // Fast non-virtual versions 676 #ifndef ASSERT 677 #define assert_same_query(xval, xcheck) xval 678 #else 679 private: 680 static bool assert_same_query(bool xval, bool xslow) { 681 assert(xval == xslow, "slow and fast queries agree"); 682 return xval; 683 } 684 public: 685 #endif 686 687 bool is_instance_klass() const { return assert_same_query(_kind <= InstanceStackChunkKlassKind, is_instance_klass_slow()); } 688 // Other is anything that is not one of the more specialized kinds of InstanceKlass. 689 bool is_other_instance_klass() const { return _kind == InstanceKlassKind; } 690 bool is_reference_instance_klass() const { return _kind == InstanceRefKlassKind; } 691 bool is_mirror_instance_klass() const { return _kind == InstanceMirrorKlassKind; } 692 bool is_class_loader_instance_klass() const { return _kind == InstanceClassLoaderKlassKind; } 693 bool is_array_klass() const { return assert_same_query( _kind >= TypeArrayKlassKind, is_array_klass_slow()); } 694 bool is_stack_chunk_instance_klass() const { return _kind == InstanceStackChunkKlassKind; } 695 bool is_objArray_klass() const { return assert_same_query( _kind == ObjArrayKlassKind, is_objArray_klass_slow()); } 696 bool is_typeArray_klass() const { return assert_same_query( _kind == TypeArrayKlassKind, is_typeArray_klass_slow()); } 697 #undef assert_same_query 698 699 // Access flags 700 AccessFlags access_flags() const { return _access_flags; } 701 void set_access_flags(AccessFlags flags) { _access_flags = flags; } 702 703 bool is_public() const { return _access_flags.is_public(); } 704 bool is_final() const { return _access_flags.is_final(); } 705 bool is_interface() const { return _access_flags.is_interface(); } 706 bool is_abstract() const { return _access_flags.is_abstract(); } 707 bool is_super() const { return _access_flags.is_super(); } 708 bool is_synthetic() const { return _access_flags.is_synthetic(); } 709 void set_is_synthetic() { _access_flags.set_is_synthetic(); } 710 bool has_finalizer() const { return _misc_flags.has_finalizer(); } 711 void set_has_finalizer() { _misc_flags.set_has_finalizer(true); } 712 bool is_hidden() const { return _misc_flags.is_hidden_class(); } 713 void set_is_hidden() { _misc_flags.set_is_hidden_class(true); } 714 bool is_value_based() const { return _misc_flags.is_value_based_class(); } 715 void set_is_value_based() { _misc_flags.set_is_value_based_class(true); } 716 717 klass_flags_t misc_flags() const { return _misc_flags.value(); } 718 719 inline bool is_non_strong_hidden() const; 720 721 bool is_cloneable() const; 722 void set_is_cloneable(); 723 724 JFR_ONLY(DEFINE_TRACE_ID_METHODS;) 725 726 virtual void metaspace_pointers_do(MetaspaceClosure* iter); 727 virtual MetaspaceObj::Type type() const { return ClassType; } 728 729 inline bool is_loader_alive() const; 730 731 void clean_subklass(); 732 733 static void clean_weak_klass_links(bool unloading_occurred, bool clean_alive_klasses = true); 734 static void clean_subklass_tree() { 735 clean_weak_klass_links(/*unloading_occurred*/ true , /* clean_alive_klasses */ false); 736 } 737 738 // Return self, except for abstract classes with exactly 1 739 // implementor. Then return the 1 concrete implementation. 740 Klass *up_cast_abstract(); 741 742 // klass name 743 Symbol* name() const { return _name; } 744 void set_name(Symbol* n); 745 746 virtual void release_C_heap_structures(bool release_constant_pool = true); 747 748 public: 749 virtual jint compute_modifier_flags() const = 0; 750 751 // JVMTI support 752 virtual jint jvmti_class_status() const; 753 754 // Printing 755 virtual void print_on(outputStream* st) const; 756 757 virtual void oop_print_value_on(oop obj, outputStream* st); 758 virtual void oop_print_on (oop obj, outputStream* st); 759 760 void print_secondary_supers_on(outputStream* st) const; 761 762 virtual const char* internal_name() const = 0; 763 764 // Verification 765 virtual void verify_on(outputStream* st); 766 void verify() { verify_on(tty); } 767 768 #ifndef PRODUCT 769 bool verify_vtable_index(int index); 770 #endif 771 772 virtual void oop_verify_on(oop obj, outputStream* st); 773 774 // for error reporting 775 static bool is_valid(Klass* k); 776 777 static void on_secondary_supers_verification_failure(Klass* super, Klass* sub, bool linear_result, bool table_result, const char* msg); 778 }; 779 780 #endif // SHARE_OOPS_KLASS_HPP --- EOF ---