1 /* 2 * Copyright (c) 1997, 2022, 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 // Klass Kinds for all subclasses of Klass 41 enum KlassKind { 42 InstanceKlassKind, 43 InlineKlassKind, 44 InstanceRefKlassKind, 45 InstanceMirrorKlassKind, 46 InstanceClassLoaderKlassKind, 47 InstanceStackChunkKlassKind, 48 TypeArrayKlassKind, 49 FlatArrayKlassKind, 50 ObjArrayKlassKind 51 }; 52 53 const uint KLASS_KIND_COUNT = ObjArrayKlassKind + 1; 54 55 // 56 // A Klass provides: 57 // 1: language level class object (method dictionary etc.) 58 // 2: provide vm dispatch behavior for the object 59 // Both functions are combined into one C++ class. 60 61 // One reason for the oop/klass dichotomy in the implementation is 62 // that we don't want a C++ vtbl pointer in every object. Thus, 63 // normal oops don't have any virtual functions. Instead, they 64 // forward all "virtual" functions to their klass, which does have 65 // a vtbl and does the C++ dispatch depending on the object's 66 // actual type. (See oop.inline.hpp for some of the forwarding code.) 67 // ALL FUNCTIONS IMPLEMENTING THIS DISPATCH ARE PREFIXED WITH "oop_"! 68 69 // Forward declarations. 70 template <class T> class Array; 71 template <class T> class GrowableArray; 72 class ClassLoaderData; 73 class fieldDescriptor; 74 class klassVtable; 75 class ModuleEntry; 76 class PackageEntry; 77 class ParCompactionManager; 78 class PSPromotionManager; 79 class vtableEntry; 80 81 class Klass : public Metadata { 82 friend class VMStructs; 83 friend class JVMCIVMStructs; 84 protected: 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, 0xA0 if value types 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 markWord _prototype_header; // inline type and inline array mark patterns 171 private: 172 // This is an index into FileMapHeader::_shared_path_table[], to 173 // associate this class with the JAR file where it's loaded from during 174 // dump time. If a class is not loaded from the shared archive, this field is 175 // -1. 176 jshort _shared_class_path_index; 177 178 #if INCLUDE_CDS 179 // Various attributes for shared classes. Should be zero for a non-shared class. 180 u2 _shared_class_flags; 181 enum CDSSharedClassFlags { 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 // Constructor 197 Klass(KlassKind kind); 198 Klass() : _kind(KlassKind(-1)) { assert(DumpSharedSpaces || UseSharedSpaces, "only for cds"); } 199 200 void* operator new(size_t size, ClassLoaderData* loader_data, size_t word_size, TRAPS) throw(); 201 202 public: 203 int kind() { return _kind; } 204 205 enum class DefaultsLookupMode { find, skip }; 206 enum class OverpassLookupMode { find, skip }; 207 enum class StaticLookupMode { find, skip }; 208 enum class PrivateLookupMode { find, skip }; 209 210 virtual bool is_klass() const { return true; } 211 212 // super() cannot be InstanceKlass* -- Java arrays are covariant, and _super is used 213 // to implement that. NB: the _super of "[Ljava/lang/Integer;" is "[Ljava/lang/Number;" 214 // If this is not what your code expects, you're probably looking for Klass::java_super(). 215 Klass* super() const { return _super; } 216 void set_super(Klass* k) { _super = k; } 217 218 // initializes _super link, _primary_supers & _secondary_supers arrays 219 void initialize_supers(Klass* k, Array<InstanceKlass*>* transitive_interfaces, TRAPS); 220 221 // klass-specific helper for initializing _secondary_supers 222 virtual GrowableArray<Klass*>* compute_secondary_supers(int num_extra_slots, 223 Array<InstanceKlass*>* transitive_interfaces); 224 225 // java_super is the Java-level super type as specified by Class.getSuperClass. 226 virtual InstanceKlass* java_super() const { return NULL; } 227 228 juint super_check_offset() const { return _super_check_offset; } 229 void set_super_check_offset(juint o) { _super_check_offset = o; } 230 231 Klass* secondary_super_cache() const { return _secondary_super_cache; } 232 void set_secondary_super_cache(Klass* k) { _secondary_super_cache = k; } 233 234 Array<Klass*>* secondary_supers() const { return _secondary_supers; } 235 void set_secondary_supers(Array<Klass*>* k) { _secondary_supers = k; } 236 237 // Return the element of the _super chain of the given depth. 238 // If there is no such element, return either NULL or this. 239 Klass* primary_super_of_depth(juint i) const { 240 assert(i < primary_super_limit(), "oob"); 241 Klass* super = _primary_supers[i]; 242 assert(super == NULL || super->super_depth() == i, "correct display"); 243 return super; 244 } 245 246 // Can this klass be a primary super? False for interfaces and arrays of 247 // interfaces. False also for arrays or classes with long super chains. 248 bool can_be_primary_super() const { 249 const juint secondary_offset = in_bytes(secondary_super_cache_offset()); 250 return super_check_offset() != secondary_offset; 251 } 252 virtual bool can_be_primary_super_slow() const; 253 254 // Returns number of primary supers; may be a number in the inclusive range [0, primary_super_limit]. 255 juint super_depth() const { 256 if (!can_be_primary_super()) { 257 return primary_super_limit(); 258 } else { 259 juint d = (super_check_offset() - in_bytes(primary_supers_offset())) / sizeof(Klass*); 260 assert(d < primary_super_limit(), "oob"); 261 assert(_primary_supers[d] == this, "proper init"); 262 return d; 263 } 264 } 265 266 // java mirror 267 oop java_mirror() const; 268 oop java_mirror_no_keepalive() const; 269 void set_java_mirror(Handle m); 270 271 oop archived_java_mirror() NOT_CDS_JAVA_HEAP_RETURN_(NULL); 272 void set_archived_java_mirror(oop m) NOT_CDS_JAVA_HEAP_RETURN; 273 274 // Temporary mirror switch used by RedefineClasses 275 OopHandle java_mirror_handle() const { return _java_mirror; } 276 void swap_java_mirror_handle(OopHandle& mirror) { _java_mirror.swap(mirror); } 277 278 // Set java mirror OopHandle to NULL for CDS 279 // This leaves the OopHandle in the CLD, but that's ok, you can't release them. 280 void clear_java_mirror_handle() { _java_mirror = OopHandle(); } 281 282 // modifier flags 283 jint modifier_flags() const { return _modifier_flags; } 284 void set_modifier_flags(jint flags) { _modifier_flags = flags; } 285 286 // size helper 287 int layout_helper() const { return _layout_helper; } 288 void set_layout_helper(int lh) { _layout_helper = lh; } 289 290 // Note: for instances layout_helper() may include padding. 291 // Use InstanceKlass::contains_field_offset to classify field offsets. 292 293 // sub/superklass links 294 Klass* subklass(bool log = false) const; 295 Klass* next_sibling(bool log = false) const; 296 297 InstanceKlass* superklass() const; 298 void append_to_sibling_list(); // add newly created receiver to superklass' subklass list 299 300 void set_next_link(Klass* k) { _next_link = k; } 301 Klass* next_link() const { return _next_link; } // The next klass defined by the class loader. 302 Klass** next_link_addr() { return &_next_link; } 303 304 // class loader data 305 ClassLoaderData* class_loader_data() const { return _class_loader_data; } 306 void set_class_loader_data(ClassLoaderData* loader_data) { _class_loader_data = loader_data; } 307 308 int shared_classpath_index() const { 309 return _shared_class_path_index; 310 }; 311 312 void set_shared_classpath_index(int index) { 313 _shared_class_path_index = index; 314 }; 315 316 bool has_archived_mirror_index() const { 317 CDS_JAVA_HEAP_ONLY(return _archived_mirror_index >= 0;) 318 NOT_CDS_JAVA_HEAP(return false); 319 } 320 321 void clear_archived_mirror_index() NOT_CDS_JAVA_HEAP_RETURN; 322 323 void set_lambda_proxy_is_available() { 324 CDS_ONLY(_shared_class_flags |= _archived_lambda_proxy_is_available;) 325 } 326 void clear_lambda_proxy_is_available() { 327 CDS_ONLY(_shared_class_flags &= ~_archived_lambda_proxy_is_available;) 328 } 329 bool lambda_proxy_is_available() const { 330 CDS_ONLY(return (_shared_class_flags & _archived_lambda_proxy_is_available) != 0;) 331 NOT_CDS(return false;) 332 } 333 334 void set_has_value_based_class_annotation() { 335 CDS_ONLY(_shared_class_flags |= _has_value_based_class_annotation;) 336 } 337 void clear_has_value_based_class_annotation() { 338 CDS_ONLY(_shared_class_flags &= ~_has_value_based_class_annotation;) 339 } 340 bool has_value_based_class_annotation() const { 341 CDS_ONLY(return (_shared_class_flags & _has_value_based_class_annotation) != 0;) 342 NOT_CDS(return false;) 343 } 344 345 void set_verified_at_dump_time() { 346 CDS_ONLY(_shared_class_flags |= _verified_at_dump_time;) 347 } 348 bool verified_at_dump_time() const { 349 CDS_ONLY(return (_shared_class_flags & _verified_at_dump_time) != 0;) 350 NOT_CDS(return false;) 351 } 352 353 void set_has_archived_enum_objs() { 354 CDS_ONLY(_shared_class_flags |= _has_archived_enum_objs;) 355 } 356 bool has_archived_enum_objs() const { 357 CDS_ONLY(return (_shared_class_flags & _has_archived_enum_objs) != 0;) 358 NOT_CDS(return false;) 359 } 360 361 void set_is_generated_shared_class() { 362 CDS_ONLY(_shared_class_flags |= _is_generated_shared_class;) 363 } 364 bool is_generated_shared_class() const { 365 CDS_ONLY(return (_shared_class_flags & _is_generated_shared_class) != 0;) 366 NOT_CDS(return false;) 367 } 368 369 // Obtain the module or package for this class 370 virtual ModuleEntry* module() const = 0; 371 virtual PackageEntry* package() const = 0; 372 373 protected: // internal accessors 374 void set_subklass(Klass* s); 375 void set_next_sibling(Klass* s); 376 377 public: 378 379 // Compiler support 380 static ByteSize super_offset() { return in_ByteSize(offset_of(Klass, _super)); } 381 static ByteSize super_check_offset_offset() { return in_ByteSize(offset_of(Klass, _super_check_offset)); } 382 static ByteSize primary_supers_offset() { return in_ByteSize(offset_of(Klass, _primary_supers)); } 383 static ByteSize secondary_super_cache_offset() { return in_ByteSize(offset_of(Klass, _secondary_super_cache)); } 384 static ByteSize secondary_supers_offset() { return in_ByteSize(offset_of(Klass, _secondary_supers)); } 385 static ByteSize java_mirror_offset() { return in_ByteSize(offset_of(Klass, _java_mirror)); } 386 static ByteSize class_loader_data_offset() { return in_ByteSize(offset_of(Klass, _class_loader_data)); } 387 static ByteSize modifier_flags_offset() { return in_ByteSize(offset_of(Klass, _modifier_flags)); } 388 static ByteSize layout_helper_offset() { return in_ByteSize(offset_of(Klass, _layout_helper)); } 389 static ByteSize access_flags_offset() { return in_ByteSize(offset_of(Klass, _access_flags)); } 390 391 // Unpacking layout_helper: 392 static const int _lh_neutral_value = 0; // neutral non-array non-instance value 393 static const int _lh_instance_slow_path_bit = 0x01; 394 static const int _lh_log2_element_size_shift = BitsPerByte*0; 395 static const int _lh_log2_element_size_mask = BitsPerLong-1; 396 static const int _lh_element_type_shift = BitsPerByte*1; 397 static const int _lh_element_type_mask = right_n_bits(BitsPerByte); // shifted mask 398 static const int _lh_header_size_shift = BitsPerByte*2; 399 static const int _lh_header_size_mask = right_n_bits(BitsPerByte); // shifted mask 400 static const int _lh_array_tag_bits = 3; 401 static const int _lh_array_tag_shift = BitsPerInt - _lh_array_tag_bits; 402 403 static const unsigned int _lh_array_tag_type_value = 0Xfffffffc; 404 static const unsigned int _lh_array_tag_vt_value = 0Xfffffffd; 405 static const unsigned int _lh_array_tag_obj_value = 0Xfffffffe; 406 407 // null-free array flag bit under the array tag bits, shift one more to get array tag value 408 static const int _lh_null_free_shift = _lh_array_tag_shift - 1; 409 static const int _lh_null_free_mask = 1; 410 411 static const jint _lh_array_tag_flat_value_bit_inplace = (jint) (1 << _lh_array_tag_shift); 412 static const jint _lh_null_free_array_bit_inplace = (jint) (_lh_null_free_mask << _lh_null_free_shift); 413 414 static int layout_helper_size_in_bytes(jint lh) { 415 assert(lh > (jint)_lh_neutral_value, "must be instance"); 416 return (int) lh & ~_lh_instance_slow_path_bit; 417 } 418 static bool layout_helper_needs_slow_path(jint lh) { 419 assert(lh > (jint)_lh_neutral_value, "must be instance"); 420 return (lh & _lh_instance_slow_path_bit) != 0; 421 } 422 static bool layout_helper_is_instance(jint lh) { 423 return (jint)lh > (jint)_lh_neutral_value; 424 } 425 static bool layout_helper_is_array(jint lh) { 426 return (jint)lh < (jint)_lh_neutral_value; 427 } 428 static bool layout_helper_is_typeArray(jint lh) { 429 return (juint) _lh_array_tag_type_value == (juint)(lh >> _lh_array_tag_shift); 430 } 431 static bool layout_helper_is_objArray(jint lh) { 432 return (juint)_lh_array_tag_obj_value == (juint)(lh >> _lh_array_tag_shift); 433 } 434 static bool layout_helper_is_flatArray(jint lh) { 435 return (juint)_lh_array_tag_vt_value == (juint)(lh >> _lh_array_tag_shift); 436 } 437 static bool layout_helper_is_null_free(jint lh) { 438 assert(layout_helper_is_flatArray(lh) || layout_helper_is_objArray(lh), "must be array of inline types"); 439 return ((lh >> _lh_null_free_shift) & _lh_null_free_mask); 440 } 441 static jint layout_helper_set_null_free(jint lh) { 442 lh |= (_lh_null_free_mask << _lh_null_free_shift); 443 assert(layout_helper_is_null_free(lh), "Bad encoding"); 444 return lh; 445 } 446 static int layout_helper_header_size(jint lh) { 447 assert(lh < (jint)_lh_neutral_value, "must be array"); 448 int hsize = (lh >> _lh_header_size_shift) & _lh_header_size_mask; 449 assert(hsize > 0 && hsize < (int)sizeof(oopDesc)*3, "sanity"); 450 return hsize; 451 } 452 static BasicType layout_helper_element_type(jint lh) { 453 assert(lh < (jint)_lh_neutral_value, "must be array"); 454 int btvalue = (lh >> _lh_element_type_shift) & _lh_element_type_mask; 455 assert((btvalue >= T_BOOLEAN && btvalue <= T_OBJECT) || btvalue == T_PRIMITIVE_OBJECT, "sanity"); 456 return (BasicType) btvalue; 457 } 458 459 // Want a pattern to quickly diff against layout header in register 460 // find something less clever! 461 static int layout_helper_boolean_diffbit() { 462 jint zlh = array_layout_helper(T_BOOLEAN); 463 jint blh = array_layout_helper(T_BYTE); 464 assert(zlh != blh, "array layout helpers must differ"); 465 int diffbit = 1; 466 while ((diffbit & (zlh ^ blh)) == 0 && (diffbit & zlh) == 0) { 467 diffbit <<= 1; 468 assert(diffbit != 0, "make sure T_BOOLEAN has a different bit than T_BYTE"); 469 } 470 return diffbit; 471 } 472 473 static int layout_helper_log2_element_size(jint lh) { 474 assert(lh < (jint)_lh_neutral_value, "must be array"); 475 int l2esz = (lh >> _lh_log2_element_size_shift) & _lh_log2_element_size_mask; 476 assert(layout_helper_element_type(lh) == T_PRIMITIVE_OBJECT || l2esz <= LogBytesPerLong, 477 "sanity. l2esz: 0x%x for lh: 0x%x", (uint)l2esz, (uint)lh); 478 return l2esz; 479 } 480 static jint array_layout_helper(jint tag, bool null_free, int hsize, BasicType etype, int log2_esize) { 481 return (tag << _lh_array_tag_shift) 482 | ((null_free ? 1 : 0) << _lh_null_free_shift) 483 | (hsize << _lh_header_size_shift) 484 | ((int)etype << _lh_element_type_shift) 485 | (log2_esize << _lh_log2_element_size_shift); 486 } 487 static jint instance_layout_helper(jint size, bool slow_path_flag) { 488 return (size << LogBytesPerWord) 489 | (slow_path_flag ? _lh_instance_slow_path_bit : 0); 490 } 491 static int layout_helper_to_size_helper(jint lh) { 492 assert(lh > (jint)_lh_neutral_value, "must be instance"); 493 // Note that the following expression discards _lh_instance_slow_path_bit. 494 return lh >> LogBytesPerWord; 495 } 496 // Out-of-line version computes everything based on the etype: 497 static jint array_layout_helper(BasicType etype); 498 499 // What is the maximum number of primary superclasses any klass can have? 500 static juint primary_super_limit() { return _primary_super_limit; } 501 502 // vtables 503 klassVtable vtable() const; 504 int vtable_length() const { return _vtable_len; } 505 506 // subclass check 507 bool is_subclass_of(const Klass* k) const; 508 // subtype check: true if is_subclass_of, or if k is interface and receiver implements it 509 bool is_subtype_of(Klass* k) const { 510 juint off = k->super_check_offset(); 511 Klass* sup = *(Klass**)( (address)this + off ); 512 const juint secondary_offset = in_bytes(secondary_super_cache_offset()); 513 if (sup == k) { 514 return true; 515 } else if (off != secondary_offset) { 516 return false; 517 } else { 518 return search_secondary_supers(k); 519 } 520 } 521 522 bool search_secondary_supers(Klass* k) const; 523 524 // Find LCA in class hierarchy 525 Klass *LCA( Klass *k ); 526 527 // Check whether reflection/jni/jvm code is allowed to instantiate this class; 528 // if not, throw either an Error or an Exception. 529 virtual void check_valid_for_instantiation(bool throwError, TRAPS); 530 531 // array copying 532 virtual void copy_array(arrayOop s, int src_pos, arrayOop d, int dst_pos, int length, TRAPS); 533 534 // tells if the class should be initialized 535 virtual bool should_be_initialized() const { return false; } 536 // initializes the klass 537 virtual void initialize(TRAPS); 538 virtual Klass* find_field(Symbol* name, Symbol* signature, fieldDescriptor* fd) const; 539 virtual Method* uncached_lookup_method(const Symbol* name, const Symbol* signature, 540 OverpassLookupMode overpass_mode, 541 PrivateLookupMode = PrivateLookupMode::find) const; 542 public: 543 Method* lookup_method(const Symbol* name, const Symbol* signature) const { 544 return uncached_lookup_method(name, signature, OverpassLookupMode::find); 545 } 546 547 // array class with specific rank 548 virtual Klass* array_klass(int rank, TRAPS) = 0; 549 550 // array class with this klass as element type 551 virtual Klass* array_klass(TRAPS) = 0; 552 553 // These will return NULL instead of allocating on the heap: 554 virtual Klass* array_klass_or_null(int rank) = 0; 555 virtual Klass* array_klass_or_null() = 0; 556 557 virtual oop protection_domain() const = 0; 558 559 oop class_loader() const; 560 561 inline oop klass_holder() const; 562 563 protected: 564 565 // Error handling when length > max_length or length < 0 566 static void check_array_allocation_length(int length, int max_length, TRAPS); 567 568 void set_vtable_length(int len) { _vtable_len= len; } 569 570 vtableEntry* start_of_vtable() const; 571 #if INCLUDE_CDS 572 void restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS); 573 #endif 574 public: 575 Method* method_at_vtable(int index); 576 577 static ByteSize vtable_start_offset(); 578 static ByteSize vtable_length_offset() { 579 return byte_offset_of(Klass, _vtable_len); 580 } 581 582 #if INCLUDE_CDS 583 // CDS support - remove and restore oops from metadata. Oops are not shared. 584 virtual void remove_unshareable_info(); 585 virtual void remove_java_mirror(); 586 587 bool is_unshareable_info_restored() const { 588 assert(is_shared(), "use this for shared classes only"); 589 if (has_archived_mirror_index()) { 590 // _java_mirror is not a valid OopHandle but rather an encoded reference in the shared heap 591 return false; 592 } else if (_java_mirror.ptr_raw() == NULL) { 593 return false; 594 } else { 595 return true; 596 } 597 } 598 #endif // INCLUDE_CDS 599 600 public: 601 // ALL FUNCTIONS BELOW THIS POINT ARE DISPATCHED FROM AN OOP 602 // These functions describe behavior for the oop not the KLASS. 603 604 // actual oop size of obj in memory in word size. 605 virtual size_t oop_size(oop obj) const = 0; 606 607 // Size of klass in word size. 608 virtual int size() const = 0; 609 610 // Returns the Java name for a class (Resource allocated) 611 // For arrays, this returns the name of the element with a leading '['. 612 // For classes, this returns the name with the package separators 613 // turned into '.'s. 614 const char* external_name() const; 615 // Returns the name for a class (Resource allocated) as the class 616 // would appear in a signature. 617 // For arrays, this returns the name of the element with a leading '['. 618 // For classes, this returns the name with a leading 'L' and a trailing ';' 619 // and the package separators as '/'. 620 virtual const char* signature_name() const; 621 622 const char* joint_in_module_of_loader(const Klass* class2, bool include_parent_loader = false) const; 623 const char* class_in_module_of_loader(bool use_are = false, bool include_parent_loader = false) const; 624 625 // Returns "interface", "abstract class" or "class". 626 const char* external_kind() const; 627 628 // type testing operations 629 #ifdef ASSERT 630 protected: 631 virtual bool is_instance_klass_slow() const { return false; } 632 virtual bool is_array_klass_slow() const { return false; } 633 virtual bool is_objArray_klass_slow() const { return false; } 634 virtual bool is_typeArray_klass_slow() const { return false; } 635 virtual bool is_flatArray_klass_slow() const { return false; } 636 #endif // ASSERT 637 // current implementation uses this method even in non debug builds 638 virtual bool is_inline_klass_slow() const { return false; } 639 public: 640 641 // Fast non-virtual versions 642 #ifndef ASSERT 643 #define assert_same_query(xval, xcheck) xval 644 #else 645 private: 646 static bool assert_same_query(bool xval, bool xslow) { 647 assert(xval == xslow, "slow and fast queries agree"); 648 return xval; 649 } 650 public: 651 #endif 652 653 bool is_instance_klass() const { return assert_same_query(_kind <= InstanceStackChunkKlassKind, is_instance_klass_slow()); } 654 bool is_inline_klass() const { return is_inline_klass_slow(); } //temporary hack 655 // Other is anything that is not one of the more specialized kinds of InstanceKlass. 656 bool is_other_instance_klass() const { return _kind <= InlineKlassKind; } 657 bool is_reference_instance_klass() const { return _kind == InstanceRefKlassKind; } 658 bool is_mirror_instance_klass() const { return _kind == InstanceMirrorKlassKind; } 659 bool is_class_loader_instance_klass() const { return _kind == InstanceClassLoaderKlassKind; } 660 bool is_array_klass() const { return assert_same_query( _kind >= TypeArrayKlassKind, is_array_klass_slow()); } 661 bool is_stack_chunk_instance_klass() const { return _kind == InstanceStackChunkKlassKind; } 662 bool is_flatArray_klass() const { return assert_same_query( _kind == FlatArrayKlassKind, is_flatArray_klass_slow()); } 663 bool is_objArray_klass() const { return assert_same_query( _kind == ObjArrayKlassKind, is_objArray_klass_slow()); } 664 bool is_typeArray_klass() const { return assert_same_query( _kind == TypeArrayKlassKind, is_typeArray_klass_slow()); } 665 #undef assert_same_query 666 667 inline bool is_null_free_array_klass() const { return layout_helper_is_null_free(layout_helper()); } 668 669 // Access flags 670 AccessFlags access_flags() const { return _access_flags; } 671 void set_access_flags(AccessFlags flags) { _access_flags = flags; } 672 673 bool is_public() const { return _access_flags.is_public(); } 674 bool is_final() const { return _access_flags.is_final(); } 675 bool is_interface() const { return _access_flags.is_interface(); } 676 bool is_abstract() const { return _access_flags.is_abstract(); } 677 bool is_synthetic() const { return _access_flags.is_synthetic(); } 678 bool is_value_class() const { return _access_flags.is_value_class(); } 679 bool is_identity_class() const { return _access_flags.is_identity_class(); } 680 void set_is_synthetic() { _access_flags.set_is_synthetic(); } 681 bool has_finalizer() const { return _access_flags.has_finalizer(); } 682 bool has_final_method() const { return _access_flags.has_final_method(); } 683 void set_has_finalizer() { _access_flags.set_has_finalizer(); } 684 void set_has_final_method() { _access_flags.set_has_final_method(); } 685 bool has_vanilla_constructor() const { return _access_flags.has_vanilla_constructor(); } 686 void set_has_vanilla_constructor() { _access_flags.set_has_vanilla_constructor(); } 687 bool has_miranda_methods () const { return access_flags().has_miranda_methods(); } 688 void set_has_miranda_methods() { _access_flags.set_has_miranda_methods(); } 689 bool is_shared() const { return access_flags().is_shared_class(); } // shadows MetaspaceObj::is_shared)() 690 void set_is_shared() { _access_flags.set_is_shared_class(); } 691 bool is_hidden() const { return access_flags().is_hidden_class(); } 692 void set_is_hidden() { _access_flags.set_is_hidden_class(); } 693 bool is_value_based() { return _access_flags.is_value_based_class(); } 694 void set_is_value_based() { _access_flags.set_is_value_based_class(); } 695 696 inline bool is_non_strong_hidden() const; 697 698 bool is_cloneable() const; 699 void set_is_cloneable(); 700 701 // inline types and inline type array patterns 702 markWord prototype_header() const { 703 return _prototype_header; 704 } 705 static inline markWord default_prototype_header(Klass* k) { 706 return (k == NULL) ? markWord::prototype() : k->prototype_header(); 707 } 708 709 inline void set_prototype_header(markWord header); 710 static ByteSize prototype_header_offset() { return in_ByteSize(offset_of(Klass, _prototype_header)); } 711 712 JFR_ONLY(DEFINE_TRACE_ID_METHODS;) 713 714 virtual void metaspace_pointers_do(MetaspaceClosure* iter); 715 virtual MetaspaceObj::Type type() const { return ClassType; } 716 717 inline bool is_loader_alive() const; 718 719 void clean_subklass(); 720 721 static void clean_weak_klass_links(bool unloading_occurred, bool clean_alive_klasses = true); 722 static void clean_subklass_tree() { 723 clean_weak_klass_links(/*unloading_occurred*/ true , /* clean_alive_klasses */ false); 724 } 725 726 // Return self, except for abstract classes with exactly 1 727 // implementor. Then return the 1 concrete implementation. 728 Klass *up_cast_abstract(); 729 730 // klass name 731 Symbol* name() const { return _name; } 732 void set_name(Symbol* n); 733 734 virtual void release_C_heap_structures(bool release_constant_pool = true); 735 736 public: 737 virtual jint compute_modifier_flags() const = 0; 738 739 // JVMTI support 740 virtual jint jvmti_class_status() const; 741 742 // Printing 743 virtual void print_on(outputStream* st) const; 744 745 virtual void oop_print_value_on(oop obj, outputStream* st); 746 virtual void oop_print_on (oop obj, outputStream* st); 747 748 virtual const char* internal_name() const = 0; 749 750 // Verification 751 virtual void verify_on(outputStream* st); 752 void verify() { verify_on(tty); } 753 754 #ifndef PRODUCT 755 bool verify_vtable_index(int index); 756 #endif 757 758 virtual void oop_verify_on(oop obj, outputStream* st); 759 760 // for error reporting 761 static bool is_valid(Klass* k); 762 }; 763 764 #endif // SHARE_OOPS_KLASS_HPP