1 /* 2 * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #ifndef SHARE_VM_OOPS_KLASS_HPP 26 #define SHARE_VM_OOPS_KLASS_HPP 27 28 #include "classfile/classLoaderData.hpp" 29 #include "gc/shared/specialized_oop_closures.hpp" 30 #include "memory/iterator.hpp" 31 #include "memory/memRegion.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 fieldDescriptor; 59 class KlassSizeStats; 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 protected: 71 // If you add a new field that points to any metaspace object, you 72 // must add this field to Klass::metaspace_pointers_do(). 73 74 // note: put frequently-used fields together at start of klass structure 75 // for better cache behavior (may not make much of a difference but sure won't hurt) 76 enum { _primary_super_limit = 8 }; 77 78 // The "layout helper" is a combined descriptor of object layout. 79 // For klasses which are neither instance nor array, the value is zero. 80 // 81 // For instances, layout helper is a positive number, the instance size. 82 // This size is already passed through align_object_size and scaled to bytes. 83 // The low order bit is set if instances of this class cannot be 84 // allocated using the fastpath. 85 // 86 // For arrays, layout helper is a negative number, containing four 87 // distinct bytes, as follows: 88 // MSB:[tag, hsz, ebt, log2(esz)]:LSB 89 // where: 90 // tag is 0x80 if the elements are oops, 0xC0 if non-oops 91 // hsz is array header size in bytes (i.e., offset of first element) 92 // ebt is the BasicType of the elements 93 // esz is the element size in bytes 94 // This packed word is arranged so as to be quickly unpacked by the 95 // various fast paths that use the various subfields. 96 // 97 // The esz bits can be used directly by a SLL instruction, without masking. 98 // 99 // Note that the array-kind tag looks like 0x00 for instance klasses, 100 // since their length in bytes is always less than 24Mb. 101 // 102 // Final note: This comes first, immediately after C++ vtable, 103 // because it is frequently queried. 104 jint _layout_helper; 105 106 // The fields _super_check_offset, _secondary_super_cache, _secondary_supers 107 // and _primary_supers all help make fast subtype checks. See big discussion 108 // in doc/server_compiler/checktype.txt 109 // 110 // Where to look to observe a supertype (it is &_secondary_super_cache for 111 // secondary supers, else is &_primary_supers[depth()]. 112 juint _super_check_offset; 113 114 // Class name. Instance classes: java/lang/String, etc. Array classes: [I, 115 // [Ljava/lang/String;, etc. Set to zero for all other kinds of classes. 116 Symbol* _name; 117 118 // Cache of last observed secondary supertype 119 Klass* _secondary_super_cache; 120 // Array of all secondary supertypes 121 Array<Klass*>* _secondary_supers; 122 // Ordered list of all primary supertypes 123 Klass* _primary_supers[_primary_super_limit]; 124 // java/lang/Class instance mirroring this class 125 OopHandle _java_mirror; 126 // Superclass 127 Klass* _super; 128 // First subclass (NULL if none); _subklass->next_sibling() is next one 129 Klass* _subklass; 130 // Sibling link (or NULL); links all subklasses of a klass 131 Klass* _next_sibling; 132 133 // All klasses loaded by a class loader are chained through these links 134 Klass* _next_link; 135 136 // The VM's representation of the ClassLoader used to load this class. 137 // Provide access the corresponding instance java.lang.ClassLoader. 138 ClassLoaderData* _class_loader_data; 139 140 jint _modifier_flags; // Processed access flags, for use by Class.getModifiers. 141 AccessFlags _access_flags; // Access flags. The class/interface distinction is stored here. 142 143 JFR_ONLY(DEFINE_TRACE_ID_FIELD;) 144 145 // Biased locking implementation and statistics 146 // (the 64-bit chunk goes first, to avoid some fragmentation) 147 jlong _last_biased_lock_bulk_revocation_time; 148 markOop _prototype_header; // Used when biased locking is both enabled and disabled for this type 149 jint _biased_lock_revocation_count; 150 151 // vtable length 152 int _vtable_len; 153 154 private: 155 // This is an index into FileMapHeader::_shared_path_table[], to 156 // associate this class with the JAR file where it's loaded from during 157 // dump time. If a class is not loaded from the shared archive, this field is 158 // -1. 159 jshort _shared_class_path_index; 160 161 #if INCLUDE_CDS 162 // Flags of the current shared class. 163 u2 _shared_class_flags; 164 enum { 165 _has_raw_archived_mirror = 1, 166 _has_signer_and_not_archived = 1 << 2 167 }; 168 #endif 169 // The _archived_mirror is set at CDS dump time pointing to the cached mirror 170 // in the open archive heap region when archiving java object is supported. 171 CDS_JAVA_HEAP_ONLY(narrowOop _archived_mirror;) 172 173 protected: 174 175 // Constructor 176 Klass(); 177 178 void* operator new(size_t size, ClassLoaderData* loader_data, size_t word_size, TRAPS) throw(); 179 180 public: 181 enum DefaultsLookupMode { find_defaults, skip_defaults }; 182 enum OverpassLookupMode { find_overpass, skip_overpass }; 183 enum StaticLookupMode { find_static, skip_static }; 184 enum PrivateLookupMode { find_private, skip_private }; 185 186 bool is_klass() const volatile { return true; } 187 188 // super 189 Klass* super() const { return _super; } 190 void set_super(Klass* k) { _super = k; } 191 192 // initializes _super link, _primary_supers & _secondary_supers arrays 193 void initialize_supers(Klass* k, Array<Klass*>* transitive_interfaces, TRAPS); 194 void initialize_supers_impl1(Klass* k); 195 void initialize_supers_impl2(Klass* k); 196 197 // klass-specific helper for initializing _secondary_supers 198 virtual GrowableArray<Klass*>* compute_secondary_supers(int num_extra_slots, 199 Array<Klass*>* transitive_interfaces); 200 201 // java_super is the Java-level super type as specified by Class.getSuperClass. 202 virtual Klass* java_super() const { return NULL; } 203 204 juint super_check_offset() const { return _super_check_offset; } 205 void set_super_check_offset(juint o) { _super_check_offset = o; } 206 207 Klass* secondary_super_cache() const { return _secondary_super_cache; } 208 void set_secondary_super_cache(Klass* k) { _secondary_super_cache = k; } 209 210 Array<Klass*>* secondary_supers() const { return _secondary_supers; } 211 void set_secondary_supers(Array<Klass*>* k) { _secondary_supers = k; } 212 213 // Return the element of the _super chain of the given depth. 214 // If there is no such element, return either NULL or this. 215 Klass* primary_super_of_depth(juint i) const { 216 assert(i < primary_super_limit(), "oob"); 217 Klass* super = _primary_supers[i]; 218 assert(super == NULL || super->super_depth() == i, "correct display"); 219 return super; 220 } 221 222 // Can this klass be a primary super? False for interfaces and arrays of 223 // interfaces. False also for arrays or classes with long super chains. 224 bool can_be_primary_super() const { 225 const juint secondary_offset = in_bytes(secondary_super_cache_offset()); 226 return super_check_offset() != secondary_offset; 227 } 228 virtual bool can_be_primary_super_slow() const; 229 230 // Returns number of primary supers; may be a number in the inclusive range [0, primary_super_limit]. 231 juint super_depth() const { 232 if (!can_be_primary_super()) { 233 return primary_super_limit(); 234 } else { 235 juint d = (super_check_offset() - in_bytes(primary_supers_offset())) / sizeof(Klass*); 236 assert(d < primary_super_limit(), "oob"); 237 assert(_primary_supers[d] == this, "proper init"); 238 return d; 239 } 240 } 241 242 // java mirror 243 oop java_mirror() const; 244 void set_java_mirror(Handle m); 245 246 oop archived_java_mirror_raw() NOT_CDS_JAVA_HEAP_RETURN_(NULL); // no GC barrier 247 void set_archived_java_mirror_raw(oop m) NOT_CDS_JAVA_HEAP_RETURN; // no GC barrier 248 249 // Temporary mirror switch used by RedefineClasses 250 // Both mirrors are on the ClassLoaderData::_handles list already so no 251 // barriers are needed. 252 void set_java_mirror_handle(OopHandle mirror) { _java_mirror = mirror; } 253 OopHandle java_mirror_handle() const { 254 return _java_mirror; 255 } 256 257 // modifier flags 258 jint modifier_flags() const { return _modifier_flags; } 259 void set_modifier_flags(jint flags) { _modifier_flags = flags; } 260 261 // size helper 262 int layout_helper() const { return _layout_helper; } 263 void set_layout_helper(int lh) { _layout_helper = lh; } 264 265 // Note: for instances layout_helper() may include padding. 266 // Use InstanceKlass::contains_field_offset to classify field offsets. 267 268 // sub/superklass links 269 Klass* subklass() const { return _subklass; } 270 Klass* next_sibling() const { return _next_sibling; } 271 InstanceKlass* superklass() const; 272 void append_to_sibling_list(); // add newly created receiver to superklass' subklass list 273 274 void set_next_link(Klass* k) { _next_link = k; } 275 Klass* next_link() const { return _next_link; } // The next klass defined by the class loader. 276 277 // class loader data 278 ClassLoaderData* class_loader_data() const { return _class_loader_data; } 279 void set_class_loader_data(ClassLoaderData* loader_data) { _class_loader_data = loader_data; } 280 281 int shared_classpath_index() const { 282 return _shared_class_path_index; 283 }; 284 285 void set_shared_classpath_index(int index) { 286 _shared_class_path_index = index; 287 }; 288 289 void set_has_raw_archived_mirror() { 290 CDS_ONLY(_shared_class_flags |= _has_raw_archived_mirror;) 291 } 292 void clear_has_raw_archived_mirror() { 293 CDS_ONLY(_shared_class_flags &= ~_has_raw_archived_mirror;) 294 } 295 bool has_raw_archived_mirror() const { 296 CDS_ONLY(return (_shared_class_flags & _has_raw_archived_mirror) != 0;) 297 NOT_CDS(return false;) 298 } 299 #if INCLUDE_CDS 300 void set_has_signer_and_not_archived() { 301 _shared_class_flags |= _has_signer_and_not_archived; 302 } 303 bool has_signer_and_not_archived() const { 304 assert(DumpSharedSpaces, "dump time only"); 305 return (_shared_class_flags & _has_signer_and_not_archived) != 0; 306 } 307 #endif // INCLUDE_CDS 308 309 // Obtain the module or package for this class 310 virtual ModuleEntry* module() const = 0; 311 virtual PackageEntry* package() const = 0; 312 313 protected: // internal accessors 314 void set_subklass(Klass* s); 315 void set_next_sibling(Klass* s); 316 317 public: 318 319 // Compiler support 320 static ByteSize super_offset() { return in_ByteSize(offset_of(Klass, _super)); } 321 static ByteSize super_check_offset_offset() { return in_ByteSize(offset_of(Klass, _super_check_offset)); } 322 static ByteSize primary_supers_offset() { return in_ByteSize(offset_of(Klass, _primary_supers)); } 323 static ByteSize secondary_super_cache_offset() { return in_ByteSize(offset_of(Klass, _secondary_super_cache)); } 324 static ByteSize secondary_supers_offset() { return in_ByteSize(offset_of(Klass, _secondary_supers)); } 325 static ByteSize java_mirror_offset() { return in_ByteSize(offset_of(Klass, _java_mirror)); } 326 static ByteSize modifier_flags_offset() { return in_ByteSize(offset_of(Klass, _modifier_flags)); } 327 static ByteSize layout_helper_offset() { return in_ByteSize(offset_of(Klass, _layout_helper)); } 328 static ByteSize access_flags_offset() { return in_ByteSize(offset_of(Klass, _access_flags)); } 329 330 // Unpacking layout_helper: 331 enum { 332 _lh_neutral_value = 0, // neutral non-array non-instance value 333 _lh_instance_slow_path_bit = 0x01, 334 _lh_log2_element_size_shift = BitsPerByte*0, 335 _lh_log2_element_size_mask = BitsPerLong-1, 336 _lh_element_type_shift = BitsPerByte*1, 337 _lh_element_type_mask = right_n_bits(BitsPerByte), // shifted mask 338 _lh_header_size_shift = BitsPerByte*2, 339 _lh_header_size_mask = right_n_bits(BitsPerByte), // shifted mask 340 _lh_array_tag_bits = 2, 341 _lh_array_tag_shift = BitsPerInt - _lh_array_tag_bits, 342 _lh_array_tag_obj_value = ~0x01 // 0x80000000 >> 30 343 }; 344 345 static const unsigned int _lh_array_tag_type_value = 0Xffffffff; // ~0x00, // 0xC0000000 >> 30 346 347 static int layout_helper_size_in_bytes(jint lh) { 348 assert(lh > (jint)_lh_neutral_value, "must be instance"); 349 return (int) lh & ~_lh_instance_slow_path_bit; 350 } 351 static bool layout_helper_needs_slow_path(jint lh) { 352 assert(lh > (jint)_lh_neutral_value, "must be instance"); 353 return (lh & _lh_instance_slow_path_bit) != 0; 354 } 355 static bool layout_helper_is_instance(jint lh) { 356 return (jint)lh > (jint)_lh_neutral_value; 357 } 358 static bool layout_helper_is_array(jint lh) { 359 return (jint)lh < (jint)_lh_neutral_value; 360 } 361 static bool layout_helper_is_typeArray(jint lh) { 362 // _lh_array_tag_type_value == (lh >> _lh_array_tag_shift); 363 return (juint)lh >= (juint)(_lh_array_tag_type_value << _lh_array_tag_shift); 364 } 365 static bool layout_helper_is_objArray(jint lh) { 366 // _lh_array_tag_obj_value == (lh >> _lh_array_tag_shift); 367 return (jint)lh < (jint)(_lh_array_tag_type_value << _lh_array_tag_shift); 368 } 369 static int layout_helper_header_size(jint lh) { 370 assert(lh < (jint)_lh_neutral_value, "must be array"); 371 int hsize = (lh >> _lh_header_size_shift) & _lh_header_size_mask; 372 assert(hsize > 0 && hsize < (int)sizeof(oopDesc)*3, "sanity"); 373 return hsize; 374 } 375 static BasicType layout_helper_element_type(jint lh) { 376 assert(lh < (jint)_lh_neutral_value, "must be array"); 377 int btvalue = (lh >> _lh_element_type_shift) & _lh_element_type_mask; 378 assert(btvalue >= T_BOOLEAN && btvalue <= T_OBJECT, "sanity"); 379 return (BasicType) btvalue; 380 } 381 382 // Want a pattern to quickly diff against layout header in register 383 // find something less clever! 384 static int layout_helper_boolean_diffbit() { 385 jint zlh = array_layout_helper(T_BOOLEAN); 386 jint blh = array_layout_helper(T_BYTE); 387 assert(zlh != blh, "array layout helpers must differ"); 388 int diffbit = 1; 389 while ((diffbit & (zlh ^ blh)) == 0 && (diffbit & zlh) == 0) { 390 diffbit <<= 1; 391 assert(diffbit != 0, "make sure T_BOOLEAN has a different bit than T_BYTE"); 392 } 393 return diffbit; 394 } 395 396 static int layout_helper_log2_element_size(jint lh) { 397 assert(lh < (jint)_lh_neutral_value, "must be array"); 398 int l2esz = (lh >> _lh_log2_element_size_shift) & _lh_log2_element_size_mask; 399 assert(l2esz <= LogBytesPerLong, 400 "sanity. l2esz: 0x%x for lh: 0x%x", (uint)l2esz, (uint)lh); 401 return l2esz; 402 } 403 static jint array_layout_helper(jint tag, int hsize, BasicType etype, int log2_esize) { 404 return (tag << _lh_array_tag_shift) 405 | (hsize << _lh_header_size_shift) 406 | ((int)etype << _lh_element_type_shift) 407 | (log2_esize << _lh_log2_element_size_shift); 408 } 409 static jint instance_layout_helper(jint size, bool slow_path_flag) { 410 return (size << LogBytesPerWord) 411 | (slow_path_flag ? _lh_instance_slow_path_bit : 0); 412 } 413 static int layout_helper_to_size_helper(jint lh) { 414 assert(lh > (jint)_lh_neutral_value, "must be instance"); 415 // Note that the following expression discards _lh_instance_slow_path_bit. 416 return lh >> LogBytesPerWord; 417 } 418 // Out-of-line version computes everything based on the etype: 419 static jint array_layout_helper(BasicType etype); 420 421 // What is the maximum number of primary superclasses any klass can have? 422 #ifdef PRODUCT 423 static juint primary_super_limit() { return _primary_super_limit; } 424 #else 425 static juint primary_super_limit() { 426 assert(FastSuperclassLimit <= _primary_super_limit, "parameter oob"); 427 return FastSuperclassLimit; 428 } 429 #endif 430 431 // vtables 432 klassVtable vtable() const; 433 int vtable_length() const { return _vtable_len; } 434 435 // subclass check 436 bool is_subclass_of(const Klass* k) const; 437 // subtype check: true if is_subclass_of, or if k is interface and receiver implements it 438 bool is_subtype_of(Klass* k) const { 439 juint off = k->super_check_offset(); 440 Klass* sup = *(Klass**)( (address)this + off ); 441 const juint secondary_offset = in_bytes(secondary_super_cache_offset()); 442 if (sup == k) { 443 return true; 444 } else if (off != secondary_offset) { 445 return false; 446 } else { 447 return search_secondary_supers(k); 448 } 449 } 450 451 bool search_secondary_supers(Klass* k) const; 452 453 // Find LCA in class hierarchy 454 Klass *LCA( Klass *k ); 455 456 // Check whether reflection/jni/jvm code is allowed to instantiate this class; 457 // if not, throw either an Error or an Exception. 458 virtual void check_valid_for_instantiation(bool throwError, TRAPS); 459 460 // array copying 461 virtual void copy_array(arrayOop s, int src_pos, arrayOop d, int dst_pos, int length, TRAPS); 462 463 // tells if the class should be initialized 464 virtual bool should_be_initialized() const { return false; } 465 // initializes the klass 466 virtual void initialize(TRAPS); 467 // lookup operation for MethodLookupCache 468 friend class MethodLookupCache; 469 virtual Klass* find_field(Symbol* name, Symbol* signature, fieldDescriptor* fd) const; 470 virtual Method* uncached_lookup_method(const Symbol* name, const Symbol* signature, OverpassLookupMode overpass_mode) const; 471 public: 472 Method* lookup_method(const Symbol* name, const Symbol* signature) const { 473 return uncached_lookup_method(name, signature, find_overpass); 474 } 475 476 // array class with specific rank 477 Klass* array_klass(int rank, TRAPS) { return array_klass_impl(false, rank, THREAD); } 478 479 // array class with this klass as element type 480 Klass* array_klass(TRAPS) { return array_klass_impl(false, THREAD); } 481 482 // These will return NULL instead of allocating on the heap: 483 // NB: these can block for a mutex, like other functions with TRAPS arg. 484 Klass* array_klass_or_null(int rank); 485 Klass* array_klass_or_null(); 486 487 virtual oop protection_domain() const = 0; 488 489 oop class_loader() const; 490 491 virtual oop klass_holder() const { return class_loader(); } 492 493 protected: 494 virtual Klass* array_klass_impl(bool or_null, int rank, TRAPS); 495 virtual Klass* array_klass_impl(bool or_null, TRAPS); 496 497 void set_vtable_length(int len) { _vtable_len= len; } 498 499 vtableEntry* start_of_vtable() const; 500 public: 501 Method* method_at_vtable(int index); 502 503 static ByteSize vtable_start_offset(); 504 static ByteSize vtable_length_offset() { 505 return byte_offset_of(Klass, _vtable_len); 506 } 507 508 // CDS support - remove and restore oops from metadata. Oops are not shared. 509 virtual void remove_unshareable_info(); 510 virtual void remove_java_mirror(); 511 virtual void restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS); 512 513 protected: 514 // computes the subtype relationship 515 virtual bool compute_is_subtype_of(Klass* k); 516 public: 517 // subclass accessor (here for convenience; undefined for non-klass objects) 518 virtual bool is_leaf_class() const { fatal("not a class"); return false; } 519 public: 520 // ALL FUNCTIONS BELOW THIS POINT ARE DISPATCHED FROM AN OOP 521 // These functions describe behavior for the oop not the KLASS. 522 523 // actual oop size of obj in memory 524 virtual int oop_size(oop obj) const = 0; 525 526 // Size of klass in word size. 527 virtual int size() const = 0; 528 #if INCLUDE_SERVICES 529 virtual void collect_statistics(KlassSizeStats *sz) const; 530 #endif 531 532 // Returns the Java name for a class (Resource allocated) 533 // For arrays, this returns the name of the element with a leading '['. 534 // For classes, this returns the name with the package separators 535 // turned into '.'s. 536 const char* external_name() const; 537 // Returns the name for a class (Resource allocated) as the class 538 // would appear in a signature. 539 // For arrays, this returns the name of the element with a leading '['. 540 // For classes, this returns the name with a leading 'L' and a trailing ';' 541 // and the package separators as '/'. 542 virtual const char* signature_name() const; 543 544 const char* class_loader_and_module_name() const; 545 546 // Returns "interface", "abstract class" or "class". 547 const char* external_kind() const; 548 549 // type testing operations 550 #ifdef ASSERT 551 protected: 552 virtual bool is_instance_klass_slow() const { return false; } 553 virtual bool is_array_klass_slow() const { return false; } 554 virtual bool is_objArray_klass_slow() const { return false; } 555 virtual bool is_typeArray_klass_slow() const { return false; } 556 #endif // ASSERT 557 public: 558 559 // Fast non-virtual versions 560 #ifndef ASSERT 561 #define assert_same_query(xval, xcheck) xval 562 #else 563 private: 564 static bool assert_same_query(bool xval, bool xslow) { 565 assert(xval == xslow, "slow and fast queries agree"); 566 return xval; 567 } 568 public: 569 #endif 570 inline bool is_instance_klass() const { return assert_same_query( 571 layout_helper_is_instance(layout_helper()), 572 is_instance_klass_slow()); } 573 inline bool is_array_klass() const { return assert_same_query( 574 layout_helper_is_array(layout_helper()), 575 is_array_klass_slow()); } 576 inline bool is_objArray_klass() const { return assert_same_query( 577 layout_helper_is_objArray(layout_helper()), 578 is_objArray_klass_slow()); } 579 inline bool is_typeArray_klass() const { return assert_same_query( 580 layout_helper_is_typeArray(layout_helper()), 581 is_typeArray_klass_slow()); } 582 #undef assert_same_query 583 584 // Access flags 585 AccessFlags access_flags() const { return _access_flags; } 586 void set_access_flags(AccessFlags flags) { _access_flags = flags; } 587 588 bool is_public() const { return _access_flags.is_public(); } 589 bool is_final() const { return _access_flags.is_final(); } 590 bool is_interface() const { return _access_flags.is_interface(); } 591 bool is_abstract() const { return _access_flags.is_abstract(); } 592 bool is_super() const { return _access_flags.is_super(); } 593 bool is_synthetic() const { return _access_flags.is_synthetic(); } 594 void set_is_synthetic() { _access_flags.set_is_synthetic(); } 595 bool has_finalizer() const { return _access_flags.has_finalizer(); } 596 bool has_final_method() const { return _access_flags.has_final_method(); } 597 void set_has_finalizer() { _access_flags.set_has_finalizer(); } 598 void set_has_final_method() { _access_flags.set_has_final_method(); } 599 bool has_vanilla_constructor() const { return _access_flags.has_vanilla_constructor(); } 600 void set_has_vanilla_constructor() { _access_flags.set_has_vanilla_constructor(); } 601 bool has_miranda_methods () const { return access_flags().has_miranda_methods(); } 602 void set_has_miranda_methods() { _access_flags.set_has_miranda_methods(); } 603 bool is_shared() const { return access_flags().is_shared_class(); } // shadows MetaspaceObj::is_shared)() 604 void set_is_shared() { _access_flags.set_is_shared_class(); } 605 606 bool is_cloneable() const; 607 void set_is_cloneable(); 608 609 // Biased locking support 610 // Note: the prototype header is always set up to be at least the 611 // prototype markOop. If biased locking is enabled it may further be 612 // biasable and have an epoch. 613 markOop prototype_header() const { return _prototype_header; } 614 // NOTE: once instances of this klass are floating around in the 615 // system, this header must only be updated at a safepoint. 616 // NOTE 2: currently we only ever set the prototype header to the 617 // biasable prototype for instanceKlasses. There is no technical 618 // reason why it could not be done for arrayKlasses aside from 619 // wanting to reduce the initial scope of this optimization. There 620 // are potential problems in setting the bias pattern for 621 // JVM-internal oops. 622 inline void set_prototype_header(markOop header); 623 static ByteSize prototype_header_offset() { return in_ByteSize(offset_of(Klass, _prototype_header)); } 624 625 int biased_lock_revocation_count() const { return (int) _biased_lock_revocation_count; } 626 // Atomically increments biased_lock_revocation_count and returns updated value 627 int atomic_incr_biased_lock_revocation_count(); 628 void set_biased_lock_revocation_count(int val) { _biased_lock_revocation_count = (jint) val; } 629 jlong last_biased_lock_bulk_revocation_time() { return _last_biased_lock_bulk_revocation_time; } 630 void set_last_biased_lock_bulk_revocation_time(jlong cur_time) { _last_biased_lock_bulk_revocation_time = cur_time; } 631 632 JFR_ONLY(DEFINE_TRACE_ID_METHODS;) 633 634 virtual void metaspace_pointers_do(MetaspaceClosure* iter); 635 virtual MetaspaceObj::Type type() const { return ClassType; } 636 637 // Iff the class loader (or mirror for anonymous classes) is alive the 638 // Klass is considered alive. Has already been marked as unloading. 639 bool is_loader_alive() const { return !class_loader_data()->is_unloading(); } 640 641 static void clean_weak_klass_links(bool unloading_occurred, bool clean_alive_klasses = true); 642 static void clean_subklass_tree() { 643 clean_weak_klass_links(/*unloading_occurred*/ true , /* clean_alive_klasses */ false); 644 } 645 646 // GC specific object visitors 647 // 648 #if INCLUDE_PARALLELGC 649 // Parallel Scavenge 650 virtual void oop_ps_push_contents( oop obj, PSPromotionManager* pm) = 0; 651 // Parallel Compact 652 virtual void oop_pc_follow_contents(oop obj, ParCompactionManager* cm) = 0; 653 virtual void oop_pc_update_pointers(oop obj, ParCompactionManager* cm) = 0; 654 #endif 655 656 // Iterators specialized to particular subtypes 657 // of ExtendedOopClosure, to avoid closure virtual calls. 658 #define Klass_OOP_OOP_ITERATE_DECL(OopClosureType, nv_suffix) \ 659 virtual void oop_oop_iterate##nv_suffix(oop obj, OopClosureType* closure) = 0; \ 660 /* Iterates "closure" over all the oops in "obj" (of type "this") within "mr". */ \ 661 virtual void oop_oop_iterate_bounded##nv_suffix(oop obj, OopClosureType* closure, MemRegion mr) = 0; 662 663 ALL_OOP_OOP_ITERATE_CLOSURES_1(Klass_OOP_OOP_ITERATE_DECL) 664 ALL_OOP_OOP_ITERATE_CLOSURES_2(Klass_OOP_OOP_ITERATE_DECL) 665 666 #if INCLUDE_OOP_OOP_ITERATE_BACKWARDS 667 #define Klass_OOP_OOP_ITERATE_DECL_BACKWARDS(OopClosureType, nv_suffix) \ 668 virtual void oop_oop_iterate_backwards##nv_suffix(oop obj, OopClosureType* closure) = 0; 669 670 ALL_OOP_OOP_ITERATE_CLOSURES_1(Klass_OOP_OOP_ITERATE_DECL_BACKWARDS) 671 ALL_OOP_OOP_ITERATE_CLOSURES_2(Klass_OOP_OOP_ITERATE_DECL_BACKWARDS) 672 #endif 673 674 virtual void array_klasses_do(void f(Klass* k)) {} 675 676 // Return self, except for abstract classes with exactly 1 677 // implementor. Then return the 1 concrete implementation. 678 Klass *up_cast_abstract(); 679 680 // klass name 681 Symbol* name() const { return _name; } 682 void set_name(Symbol* n); 683 684 public: 685 // jvm support 686 virtual jint compute_modifier_flags(TRAPS) const; 687 688 // JVMTI support 689 virtual jint jvmti_class_status() const; 690 691 // Printing 692 virtual void print_on(outputStream* st) const; 693 694 virtual void oop_print_value_on(oop obj, outputStream* st); 695 virtual void oop_print_on (oop obj, outputStream* st); 696 697 virtual const char* internal_name() const = 0; 698 699 // Verification 700 virtual void verify_on(outputStream* st); 701 void verify() { verify_on(tty); } 702 703 #ifndef PRODUCT 704 bool verify_vtable_index(int index); 705 bool verify_itable_index(int index); 706 #endif 707 708 virtual void oop_verify_on(oop obj, outputStream* st); 709 710 static bool is_null(narrowKlass obj); 711 static bool is_null(Klass* obj); 712 713 // klass encoding for klass pointer in objects. 714 static narrowKlass encode_klass_not_null(Klass* v); 715 static narrowKlass encode_klass(Klass* v); 716 717 static Klass* decode_klass_not_null(narrowKlass v); 718 static Klass* decode_klass(narrowKlass v); 719 }; 720 721 // Helper to convert the oop iterate macro suffixes into bool values that can be used by template functions. 722 #define nvs_nv_to_bool true 723 #define nvs_v_to_bool false 724 #define nvs_to_bool(nv_suffix) nvs##nv_suffix##_to_bool 725 726 // Oop iteration macros for declarations. 727 // Used to generate declarations in the *Klass header files. 728 729 #define OOP_OOP_ITERATE_DECL(OopClosureType, nv_suffix) \ 730 void oop_oop_iterate##nv_suffix(oop obj, OopClosureType* closure); \ 731 void oop_oop_iterate_bounded##nv_suffix(oop obj, OopClosureType* closure, MemRegion mr); 732 733 #if INCLUDE_OOP_OOP_ITERATE_BACKWARDS 734 #define OOP_OOP_ITERATE_DECL_BACKWARDS(OopClosureType, nv_suffix) \ 735 void oop_oop_iterate_backwards##nv_suffix(oop obj, OopClosureType* closure); 736 #endif 737 738 739 // Oop iteration macros for definitions. 740 // Used to generate definitions in the *Klass.inline.hpp files. 741 742 #define OOP_OOP_ITERATE_DEFN(KlassType, OopClosureType, nv_suffix) \ 743 void KlassType::oop_oop_iterate##nv_suffix(oop obj, OopClosureType* closure) { \ 744 oop_oop_iterate<nvs_to_bool(nv_suffix)>(obj, closure); \ 745 } 746 747 #if INCLUDE_OOP_OOP_ITERATE_BACKWARDS 748 #define OOP_OOP_ITERATE_DEFN_BACKWARDS(KlassType, OopClosureType, nv_suffix) \ 749 void KlassType::oop_oop_iterate_backwards##nv_suffix(oop obj, OopClosureType* closure) { \ 750 oop_oop_iterate_reverse<nvs_to_bool(nv_suffix)>(obj, closure); \ 751 } 752 #else 753 #define OOP_OOP_ITERATE_DEFN_BACKWARDS(KlassType, OopClosureType, nv_suffix) 754 #endif 755 756 #define OOP_OOP_ITERATE_DEFN_BOUNDED(KlassType, OopClosureType, nv_suffix) \ 757 void KlassType::oop_oop_iterate_bounded##nv_suffix(oop obj, OopClosureType* closure, MemRegion mr) { \ 758 oop_oop_iterate_bounded<nvs_to_bool(nv_suffix)>(obj, closure, mr); \ 759 } 760 761 #endif // SHARE_VM_OOPS_KLASS_HPP