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 "memory/iterator.hpp" 30 #include "memory/memRegion.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 IDs for all subclasses of Klass 41 enum KlassID { 42 InstanceKlassID, 43 InstanceRefKlassID, 44 InstanceMirrorKlassID, 45 InstanceClassLoaderKlassID, 46 TypeArrayKlassID, 47 ObjArrayKlassID 48 }; 49 50 const uint KLASS_ID_COUNT = 6; 51 52 // 53 // A Klass provides: 54 // 1: language level class object (method dictionary etc.) 55 // 2: provide vm dispatch behavior for the object 56 // Both functions are combined into one C++ class. 57 58 // One reason for the oop/klass dichotomy in the implementation is 59 // that we don't want a C++ vtbl pointer in every object. Thus, 60 // normal oops don't have any virtual functions. Instead, they 61 // forward all "virtual" functions to their klass, which does have 62 // a vtbl and does the C++ dispatch depending on the object's 63 // actual type. (See oop.inline.hpp for some of the forwarding code.) 64 // ALL FUNCTIONS IMPLEMENTING THIS DISPATCH ARE PREFIXED WITH "oop_"! 65 66 // Forward declarations. 67 template <class T> class Array; 68 template <class T> class GrowableArray; 69 class fieldDescriptor; 70 class KlassSizeStats; 71 class klassVtable; 72 class ModuleEntry; 73 class PackageEntry; 74 class ParCompactionManager; 75 class PSPromotionManager; 76 class vtableEntry; 77 78 class Klass : public Metadata { 79 friend class VMStructs; 80 friend class JVMCIVMStructs; 81 protected: 82 // If you add a new field that points to any metaspace object, you 83 // must add this field to Klass::metaspace_pointers_do(). 84 85 // note: put frequently-used fields together at start of klass structure 86 // for better cache behavior (may not make much of a difference but sure won't hurt) 87 enum { _primary_super_limit = 8 }; 88 89 // The "layout helper" is a combined descriptor of object layout. 90 // For klasses which are neither instance nor array, the value is zero. 91 // 92 // For instances, layout helper is a positive number, the instance size. 93 // This size is already passed through align_object_size and scaled to bytes. 94 // The low order bit is set if instances of this class cannot be 95 // allocated using the fastpath. 96 // 97 // For arrays, layout helper is a negative number, containing four 98 // distinct bytes, as follows: 99 // MSB:[tag, hsz, ebt, log2(esz)]:LSB 100 // where: 101 // tag is 0x80 if the elements are oops, 0xC0 if non-oops 102 // hsz is array header size in bytes (i.e., offset of first element) 103 // ebt is the BasicType of the elements 104 // esz is the element size in bytes 105 // This packed word is arranged so as to be quickly unpacked by the 106 // various fast paths that use the various subfields. 107 // 108 // The esz bits can be used directly by a SLL instruction, without masking. 109 // 110 // Note that the array-kind tag looks like 0x00 for instance klasses, 111 // since their length in bytes is always less than 24Mb. 112 // 113 // Final note: This comes first, immediately after C++ vtable, 114 // because it is frequently queried. 115 jint _layout_helper; 116 117 // Klass identifier used to implement devirtualized oop closure dispatching. 118 const KlassID _id; 119 120 // The fields _super_check_offset, _secondary_super_cache, _secondary_supers 121 // and _primary_supers all help make fast subtype checks. See big discussion 122 // in doc/server_compiler/checktype.txt 123 // 124 // Where to look to observe a supertype (it is &_secondary_super_cache for 125 // secondary supers, else is &_primary_supers[depth()]. 126 juint _super_check_offset; 127 128 // Class name. Instance classes: java/lang/String, etc. Array classes: [I, 129 // [Ljava/lang/String;, etc. Set to zero for all other kinds of classes. 130 Symbol* _name; 131 132 // Cache of last observed secondary supertype 133 Klass* _secondary_super_cache; 134 // Array of all secondary supertypes 135 Array<Klass*>* _secondary_supers; 136 // Ordered list of all primary supertypes 137 Klass* _primary_supers[_primary_super_limit]; 138 // java/lang/Class instance mirroring this class 139 OopHandle _java_mirror; 140 // Superclass 141 Klass* _super; 142 // First subclass (NULL if none); _subklass->next_sibling() is next one 143 Klass* _subklass; 144 // Sibling link (or NULL); links all subklasses of a klass 145 Klass* _next_sibling; 146 147 // All klasses loaded by a class loader are chained through these links 148 Klass* _next_link; 149 150 // The VM's representation of the ClassLoader used to load this class. 151 // Provide access the corresponding instance java.lang.ClassLoader. 152 ClassLoaderData* _class_loader_data; 153 154 jint _modifier_flags; // Processed access flags, for use by Class.getModifiers. 155 AccessFlags _access_flags; // Access flags. The class/interface distinction is stored here. 156 157 JFR_ONLY(DEFINE_TRACE_ID_FIELD;) 158 159 // Biased locking implementation and statistics 160 // (the 64-bit chunk goes first, to avoid some fragmentation) 161 jlong _last_biased_lock_bulk_revocation_time; 162 markOop _prototype_header; // Used when biased locking is both enabled and disabled for this type 163 jint _biased_lock_revocation_count; 164 165 // vtable length 166 int _vtable_len; 167 168 private: 169 // This is an index into FileMapHeader::_shared_path_table[], to 170 // associate this class with the JAR file where it's loaded from during 171 // dump time. If a class is not loaded from the shared archive, this field is 172 // -1. 173 jshort _shared_class_path_index; 174 175 #if INCLUDE_CDS 176 // Flags of the current shared class. 177 u2 _shared_class_flags; 178 enum { 179 _has_raw_archived_mirror = 1, 180 _has_signer_and_not_archived = 1 << 2 181 }; 182 #endif 183 // The _archived_mirror is set at CDS dump time pointing to the cached mirror 184 // in the open archive heap region when archiving java object is supported. 185 CDS_JAVA_HEAP_ONLY(narrowOop _archived_mirror;) 186 187 protected: 188 189 // Constructor 190 Klass(KlassID id); 191 Klass() : _id(KlassID(-1)) { assert(DumpSharedSpaces || UseSharedSpaces, "only for cds"); } 192 193 void* operator new(size_t size, ClassLoaderData* loader_data, size_t word_size, TRAPS) throw(); 194 195 public: 196 int id() { return _id; } 197 198 enum DefaultsLookupMode { find_defaults, skip_defaults }; 199 enum OverpassLookupMode { find_overpass, skip_overpass }; 200 enum StaticLookupMode { find_static, skip_static }; 201 enum PrivateLookupMode { find_private, skip_private }; 202 203 bool is_klass() const volatile { return true; } 204 205 // super 206 Klass* super() const { return _super; } 207 void set_super(Klass* k) { _super = k; } 208 209 // initializes _super link, _primary_supers & _secondary_supers arrays 210 void initialize_supers(Klass* k, Array<Klass*>* transitive_interfaces, TRAPS); 211 void initialize_supers_impl1(Klass* k); 212 void initialize_supers_impl2(Klass* k); 213 214 // klass-specific helper for initializing _secondary_supers 215 virtual GrowableArray<Klass*>* compute_secondary_supers(int num_extra_slots, 216 Array<Klass*>* transitive_interfaces); 217 218 // java_super is the Java-level super type as specified by Class.getSuperClass. 219 virtual Klass* java_super() const { return NULL; } 220 221 juint super_check_offset() const { return _super_check_offset; } 222 void set_super_check_offset(juint o) { _super_check_offset = o; } 223 224 Klass* secondary_super_cache() const { return _secondary_super_cache; } 225 void set_secondary_super_cache(Klass* k) { _secondary_super_cache = k; } 226 227 Array<Klass*>* secondary_supers() const { return _secondary_supers; } 228 void set_secondary_supers(Array<Klass*>* k) { _secondary_supers = k; } 229 230 // Return the element of the _super chain of the given depth. 231 // If there is no such element, return either NULL or this. 232 Klass* primary_super_of_depth(juint i) const { 233 assert(i < primary_super_limit(), "oob"); 234 Klass* super = _primary_supers[i]; 235 assert(super == NULL || super->super_depth() == i, "correct display"); 236 return super; 237 } 238 239 // Can this klass be a primary super? False for interfaces and arrays of 240 // interfaces. False also for arrays or classes with long super chains. 241 bool can_be_primary_super() const { 242 const juint secondary_offset = in_bytes(secondary_super_cache_offset()); 243 return super_check_offset() != secondary_offset; 244 } 245 virtual bool can_be_primary_super_slow() const; 246 247 // Returns number of primary supers; may be a number in the inclusive range [0, primary_super_limit]. 248 juint super_depth() const { 249 if (!can_be_primary_super()) { 250 return primary_super_limit(); 251 } else { 252 juint d = (super_check_offset() - in_bytes(primary_supers_offset())) / sizeof(Klass*); 253 assert(d < primary_super_limit(), "oob"); 254 assert(_primary_supers[d] == this, "proper init"); 255 return d; 256 } 257 } 258 259 // java mirror 260 oop java_mirror() const; 261 void set_java_mirror(Handle m); 262 263 oop archived_java_mirror_raw() NOT_CDS_JAVA_HEAP_RETURN_(NULL); // no GC barrier 264 void set_archived_java_mirror_raw(oop m) NOT_CDS_JAVA_HEAP_RETURN; // no GC barrier 265 266 // Temporary mirror switch used by RedefineClasses 267 // Both mirrors are on the ClassLoaderData::_handles list already so no 268 // barriers are needed. 269 void set_java_mirror_handle(OopHandle mirror) { _java_mirror = mirror; } 270 OopHandle java_mirror_handle() const { 271 return _java_mirror; 272 } 273 274 // modifier flags 275 jint modifier_flags() const { return _modifier_flags; } 276 void set_modifier_flags(jint flags) { _modifier_flags = flags; } 277 278 // size helper 279 int layout_helper() const { return _layout_helper; } 280 void set_layout_helper(int lh) { _layout_helper = lh; } 281 282 // Note: for instances layout_helper() may include padding. 283 // Use InstanceKlass::contains_field_offset to classify field offsets. 284 285 // sub/superklass links 286 Klass* subklass() const { return _subklass; } 287 Klass* next_sibling() const { return _next_sibling; } 288 InstanceKlass* superklass() const; 289 void append_to_sibling_list(); // add newly created receiver to superklass' subklass list 290 291 void set_next_link(Klass* k) { _next_link = k; } 292 Klass* next_link() const { return _next_link; } // The next klass defined by the class loader. 293 294 // class loader data 295 ClassLoaderData* class_loader_data() const { return _class_loader_data; } 296 void set_class_loader_data(ClassLoaderData* loader_data) { _class_loader_data = loader_data; } 297 298 int shared_classpath_index() const { 299 return _shared_class_path_index; 300 }; 301 302 void set_shared_classpath_index(int index) { 303 _shared_class_path_index = index; 304 }; 305 306 void set_has_raw_archived_mirror() { 307 CDS_ONLY(_shared_class_flags |= _has_raw_archived_mirror;) 308 } 309 void clear_has_raw_archived_mirror() { 310 CDS_ONLY(_shared_class_flags &= ~_has_raw_archived_mirror;) 311 } 312 bool has_raw_archived_mirror() const { 313 CDS_ONLY(return (_shared_class_flags & _has_raw_archived_mirror) != 0;) 314 NOT_CDS(return false;) 315 } 316 #if INCLUDE_CDS 317 void set_has_signer_and_not_archived() { 318 _shared_class_flags |= _has_signer_and_not_archived; 319 } 320 bool has_signer_and_not_archived() const { 321 assert(DumpSharedSpaces, "dump time only"); 322 return (_shared_class_flags & _has_signer_and_not_archived) != 0; 323 } 324 #endif // INCLUDE_CDS 325 326 // Obtain the module or package for this class 327 virtual ModuleEntry* module() const = 0; 328 virtual PackageEntry* package() const = 0; 329 330 protected: // internal accessors 331 void set_subklass(Klass* s); 332 void set_next_sibling(Klass* s); 333 334 public: 335 336 // Compiler support 337 static ByteSize super_offset() { return in_ByteSize(offset_of(Klass, _super)); } 338 static ByteSize super_check_offset_offset() { return in_ByteSize(offset_of(Klass, _super_check_offset)); } 339 static ByteSize primary_supers_offset() { return in_ByteSize(offset_of(Klass, _primary_supers)); } 340 static ByteSize secondary_super_cache_offset() { return in_ByteSize(offset_of(Klass, _secondary_super_cache)); } 341 static ByteSize secondary_supers_offset() { return in_ByteSize(offset_of(Klass, _secondary_supers)); } 342 static ByteSize java_mirror_offset() { return in_ByteSize(offset_of(Klass, _java_mirror)); } 343 static ByteSize modifier_flags_offset() { return in_ByteSize(offset_of(Klass, _modifier_flags)); } 344 static ByteSize layout_helper_offset() { return in_ByteSize(offset_of(Klass, _layout_helper)); } 345 static ByteSize access_flags_offset() { return in_ByteSize(offset_of(Klass, _access_flags)); } 346 347 // Unpacking layout_helper: 348 enum { 349 _lh_neutral_value = 0, // neutral non-array non-instance value 350 _lh_instance_slow_path_bit = 0x01, 351 _lh_log2_element_size_shift = BitsPerByte*0, 352 _lh_log2_element_size_mask = BitsPerLong-1, 353 _lh_element_type_shift = BitsPerByte*1, 354 _lh_element_type_mask = right_n_bits(BitsPerByte), // shifted mask 355 _lh_header_size_shift = BitsPerByte*2, 356 _lh_header_size_mask = right_n_bits(BitsPerByte), // shifted mask 357 _lh_array_tag_bits = 2, 358 _lh_array_tag_shift = BitsPerInt - _lh_array_tag_bits, 359 _lh_array_tag_obj_value = ~0x01 // 0x80000000 >> 30 360 }; 361 362 static const unsigned int _lh_array_tag_type_value = 0Xffffffff; // ~0x00, // 0xC0000000 >> 30 363 364 static int layout_helper_size_in_bytes(jint lh) { 365 assert(lh > (jint)_lh_neutral_value, "must be instance"); 366 return (int) lh & ~_lh_instance_slow_path_bit; 367 } 368 static bool layout_helper_needs_slow_path(jint lh) { 369 assert(lh > (jint)_lh_neutral_value, "must be instance"); 370 return (lh & _lh_instance_slow_path_bit) != 0; 371 } 372 static bool layout_helper_is_instance(jint lh) { 373 return (jint)lh > (jint)_lh_neutral_value; 374 } 375 static bool layout_helper_is_array(jint lh) { 376 return (jint)lh < (jint)_lh_neutral_value; 377 } 378 static bool layout_helper_is_typeArray(jint lh) { 379 // _lh_array_tag_type_value == (lh >> _lh_array_tag_shift); 380 return (juint)lh >= (juint)(_lh_array_tag_type_value << _lh_array_tag_shift); 381 } 382 static bool layout_helper_is_objArray(jint lh) { 383 // _lh_array_tag_obj_value == (lh >> _lh_array_tag_shift); 384 return (jint)lh < (jint)(_lh_array_tag_type_value << _lh_array_tag_shift); 385 } 386 static int layout_helper_header_size(jint lh) { 387 assert(lh < (jint)_lh_neutral_value, "must be array"); 388 int hsize = (lh >> _lh_header_size_shift) & _lh_header_size_mask; 389 assert(hsize > 0 && hsize < (int)sizeof(oopDesc)*3, "sanity"); 390 return hsize; 391 } 392 static BasicType layout_helper_element_type(jint lh) { 393 assert(lh < (jint)_lh_neutral_value, "must be array"); 394 int btvalue = (lh >> _lh_element_type_shift) & _lh_element_type_mask; 395 assert(btvalue >= T_BOOLEAN && btvalue <= T_OBJECT, "sanity"); 396 return (BasicType) btvalue; 397 } 398 399 // Want a pattern to quickly diff against layout header in register 400 // find something less clever! 401 static int layout_helper_boolean_diffbit() { 402 jint zlh = array_layout_helper(T_BOOLEAN); 403 jint blh = array_layout_helper(T_BYTE); 404 assert(zlh != blh, "array layout helpers must differ"); 405 int diffbit = 1; 406 while ((diffbit & (zlh ^ blh)) == 0 && (diffbit & zlh) == 0) { 407 diffbit <<= 1; 408 assert(diffbit != 0, "make sure T_BOOLEAN has a different bit than T_BYTE"); 409 } 410 return diffbit; 411 } 412 413 static int layout_helper_log2_element_size(jint lh) { 414 assert(lh < (jint)_lh_neutral_value, "must be array"); 415 int l2esz = (lh >> _lh_log2_element_size_shift) & _lh_log2_element_size_mask; 416 assert(l2esz <= LogBytesPerLong, 417 "sanity. l2esz: 0x%x for lh: 0x%x", (uint)l2esz, (uint)lh); 418 return l2esz; 419 } 420 static jint array_layout_helper(jint tag, int hsize, BasicType etype, int log2_esize) { 421 return (tag << _lh_array_tag_shift) 422 | (hsize << _lh_header_size_shift) 423 | ((int)etype << _lh_element_type_shift) 424 | (log2_esize << _lh_log2_element_size_shift); 425 } 426 static jint instance_layout_helper(jint size, bool slow_path_flag) { 427 return (size << LogBytesPerWord) 428 | (slow_path_flag ? _lh_instance_slow_path_bit : 0); 429 } 430 static int layout_helper_to_size_helper(jint lh) { 431 assert(lh > (jint)_lh_neutral_value, "must be instance"); 432 // Note that the following expression discards _lh_instance_slow_path_bit. 433 return lh >> LogBytesPerWord; 434 } 435 // Out-of-line version computes everything based on the etype: 436 static jint array_layout_helper(BasicType etype); 437 438 // What is the maximum number of primary superclasses any klass can have? 439 #ifdef PRODUCT 440 static juint primary_super_limit() { return _primary_super_limit; } 441 #else 442 static juint primary_super_limit() { 443 assert(FastSuperclassLimit <= _primary_super_limit, "parameter oob"); 444 return FastSuperclassLimit; 445 } 446 #endif 447 448 // vtables 449 klassVtable vtable() const; 450 int vtable_length() const { return _vtable_len; } 451 452 // subclass check 453 bool is_subclass_of(const Klass* k) const; 454 // subtype check: true if is_subclass_of, or if k is interface and receiver implements it 455 bool is_subtype_of(Klass* k) const { 456 juint off = k->super_check_offset(); 457 Klass* sup = *(Klass**)( (address)this + off ); 458 const juint secondary_offset = in_bytes(secondary_super_cache_offset()); 459 if (sup == k) { 460 return true; 461 } else if (off != secondary_offset) { 462 return false; 463 } else { 464 return search_secondary_supers(k); 465 } 466 } 467 468 bool search_secondary_supers(Klass* k) const; 469 470 // Find LCA in class hierarchy 471 Klass *LCA( Klass *k ); 472 473 // Check whether reflection/jni/jvm code is allowed to instantiate this class; 474 // if not, throw either an Error or an Exception. 475 virtual void check_valid_for_instantiation(bool throwError, TRAPS); 476 477 // array copying 478 virtual void copy_array(arrayOop s, int src_pos, arrayOop d, int dst_pos, int length, TRAPS); 479 480 // tells if the class should be initialized 481 virtual bool should_be_initialized() const { return false; } 482 // initializes the klass 483 virtual void initialize(TRAPS); 484 // lookup operation for MethodLookupCache 485 friend class MethodLookupCache; 486 virtual Klass* find_field(Symbol* name, Symbol* signature, fieldDescriptor* fd) const; 487 virtual Method* uncached_lookup_method(const Symbol* name, const Symbol* signature, 488 OverpassLookupMode overpass_mode, 489 PrivateLookupMode = find_private) const; 490 public: 491 Method* lookup_method(const Symbol* name, const Symbol* signature) const { 492 return uncached_lookup_method(name, signature, find_overpass); 493 } 494 495 // array class with specific rank 496 Klass* array_klass(int rank, TRAPS) { return array_klass_impl(false, rank, THREAD); } 497 498 // array class with this klass as element type 499 Klass* array_klass(TRAPS) { return array_klass_impl(false, THREAD); } 500 501 // These will return NULL instead of allocating on the heap: 502 // NB: these can block for a mutex, like other functions with TRAPS arg. 503 Klass* array_klass_or_null(int rank); 504 Klass* array_klass_or_null(); 505 506 virtual oop protection_domain() const = 0; 507 508 oop class_loader() const; 509 510 virtual oop klass_holder() const { return class_loader(); } 511 512 protected: 513 virtual Klass* array_klass_impl(bool or_null, int rank, TRAPS); 514 virtual Klass* array_klass_impl(bool or_null, TRAPS); 515 516 void set_vtable_length(int len) { _vtable_len= len; } 517 518 vtableEntry* start_of_vtable() const; 519 public: 520 Method* method_at_vtable(int index); 521 522 static ByteSize vtable_start_offset(); 523 static ByteSize vtable_length_offset() { 524 return byte_offset_of(Klass, _vtable_len); 525 } 526 527 // CDS support - remove and restore oops from metadata. Oops are not shared. 528 virtual void remove_unshareable_info(); 529 virtual void remove_java_mirror(); 530 virtual void restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS); 531 532 protected: 533 // computes the subtype relationship 534 virtual bool compute_is_subtype_of(Klass* k); 535 public: 536 // subclass accessor (here for convenience; undefined for non-klass objects) 537 virtual bool is_leaf_class() const { fatal("not a class"); return false; } 538 public: 539 // ALL FUNCTIONS BELOW THIS POINT ARE DISPATCHED FROM AN OOP 540 // These functions describe behavior for the oop not the KLASS. 541 542 // actual oop size of obj in memory 543 virtual int oop_size(oop obj) const = 0; 544 545 // Size of klass in word size. 546 virtual int size() const = 0; 547 #if INCLUDE_SERVICES 548 virtual void collect_statistics(KlassSizeStats *sz) const; 549 #endif 550 551 // Returns the Java name for a class (Resource allocated) 552 // For arrays, this returns the name of the element with a leading '['. 553 // For classes, this returns the name with the package separators 554 // turned into '.'s. 555 const char* external_name() const; 556 // Returns the name for a class (Resource allocated) as the class 557 // would appear in a signature. 558 // For arrays, this returns the name of the element with a leading '['. 559 // For classes, this returns the name with a leading 'L' and a trailing ';' 560 // and the package separators as '/'. 561 virtual const char* signature_name() const; 562 563 const char* joint_in_module_of_loader(const Klass* class2, bool include_parent_loader = false) const; 564 const char* class_in_module_of_loader(bool use_are = false, bool include_parent_loader = false) const; 565 566 // Returns "interface", "abstract class" or "class". 567 const char* external_kind() const; 568 569 // type testing operations 570 #ifdef ASSERT 571 protected: 572 virtual bool is_instance_klass_slow() const { return false; } 573 virtual bool is_array_klass_slow() const { return false; } 574 virtual bool is_objArray_klass_slow() const { return false; } 575 virtual bool is_typeArray_klass_slow() const { return false; } 576 #endif // ASSERT 577 public: 578 579 // Fast non-virtual versions 580 #ifndef ASSERT 581 #define assert_same_query(xval, xcheck) xval 582 #else 583 private: 584 static bool assert_same_query(bool xval, bool xslow) { 585 assert(xval == xslow, "slow and fast queries agree"); 586 return xval; 587 } 588 public: 589 #endif 590 inline bool is_instance_klass() const { return assert_same_query( 591 layout_helper_is_instance(layout_helper()), 592 is_instance_klass_slow()); } 593 inline bool is_array_klass() const { return assert_same_query( 594 layout_helper_is_array(layout_helper()), 595 is_array_klass_slow()); } 596 inline bool is_objArray_klass() const { return assert_same_query( 597 layout_helper_is_objArray(layout_helper()), 598 is_objArray_klass_slow()); } 599 inline bool is_typeArray_klass() const { return assert_same_query( 600 layout_helper_is_typeArray(layout_helper()), 601 is_typeArray_klass_slow()); } 602 #undef assert_same_query 603 604 // Access flags 605 AccessFlags access_flags() const { return _access_flags; } 606 void set_access_flags(AccessFlags flags) { _access_flags = flags; } 607 608 bool is_public() const { return _access_flags.is_public(); } 609 bool is_final() const { return _access_flags.is_final(); } 610 bool is_interface() const { return _access_flags.is_interface(); } 611 bool is_abstract() const { return _access_flags.is_abstract(); } 612 bool is_super() const { return _access_flags.is_super(); } 613 bool is_synthetic() const { return _access_flags.is_synthetic(); } 614 void set_is_synthetic() { _access_flags.set_is_synthetic(); } 615 bool has_finalizer() const { return _access_flags.has_finalizer(); } 616 bool has_final_method() const { return _access_flags.has_final_method(); } 617 void set_has_finalizer() { _access_flags.set_has_finalizer(); } 618 void set_has_final_method() { _access_flags.set_has_final_method(); } 619 bool has_vanilla_constructor() const { return _access_flags.has_vanilla_constructor(); } 620 void set_has_vanilla_constructor() { _access_flags.set_has_vanilla_constructor(); } 621 bool has_miranda_methods () const { return access_flags().has_miranda_methods(); } 622 void set_has_miranda_methods() { _access_flags.set_has_miranda_methods(); } 623 bool is_shared() const { return access_flags().is_shared_class(); } // shadows MetaspaceObj::is_shared)() 624 void set_is_shared() { _access_flags.set_is_shared_class(); } 625 626 bool is_cloneable() const; 627 void set_is_cloneable(); 628 629 // Biased locking support 630 // Note: the prototype header is always set up to be at least the 631 // prototype markOop. If biased locking is enabled it may further be 632 // biasable and have an epoch. 633 markOop prototype_header() const { return _prototype_header; } 634 // NOTE: once instances of this klass are floating around in the 635 // system, this header must only be updated at a safepoint. 636 // NOTE 2: currently we only ever set the prototype header to the 637 // biasable prototype for instanceKlasses. There is no technical 638 // reason why it could not be done for arrayKlasses aside from 639 // wanting to reduce the initial scope of this optimization. There 640 // are potential problems in setting the bias pattern for 641 // JVM-internal oops. 642 inline void set_prototype_header(markOop header); 643 static ByteSize prototype_header_offset() { return in_ByteSize(offset_of(Klass, _prototype_header)); } 644 645 int biased_lock_revocation_count() const { return (int) _biased_lock_revocation_count; } 646 // Atomically increments biased_lock_revocation_count and returns updated value 647 int atomic_incr_biased_lock_revocation_count(); 648 void set_biased_lock_revocation_count(int val) { _biased_lock_revocation_count = (jint) val; } 649 jlong last_biased_lock_bulk_revocation_time() { return _last_biased_lock_bulk_revocation_time; } 650 void set_last_biased_lock_bulk_revocation_time(jlong cur_time) { _last_biased_lock_bulk_revocation_time = cur_time; } 651 652 JFR_ONLY(DEFINE_TRACE_ID_METHODS;) 653 654 virtual void metaspace_pointers_do(MetaspaceClosure* iter); 655 virtual MetaspaceObj::Type type() const { return ClassType; } 656 657 // Iff the class loader (or mirror for anonymous classes) is alive the 658 // Klass is considered alive. Has already been marked as unloading. 659 bool is_loader_alive() const { return !class_loader_data()->is_unloading(); } 660 661 // Load the klass's holder as a phantom. This is useful when a weak Klass 662 // pointer has been "peeked" and then must be kept alive before it may 663 // be used safely. 664 oop holder_phantom() const; 665 666 static void clean_weak_klass_links(bool unloading_occurred, bool clean_alive_klasses = true); 667 static void clean_subklass_tree() { 668 clean_weak_klass_links(/*unloading_occurred*/ true , /* clean_alive_klasses */ false); 669 } 670 671 // GC specific object visitors 672 // 673 #if INCLUDE_PARALLELGC 674 // Parallel Scavenge 675 virtual void oop_ps_push_contents( oop obj, PSPromotionManager* pm) = 0; 676 // Parallel Compact 677 virtual void oop_pc_follow_contents(oop obj, ParCompactionManager* cm) = 0; 678 virtual void oop_pc_update_pointers(oop obj, ParCompactionManager* cm) = 0; 679 #endif 680 681 virtual void array_klasses_do(void f(Klass* k)) {} 682 683 // Return self, except for abstract classes with exactly 1 684 // implementor. Then return the 1 concrete implementation. 685 Klass *up_cast_abstract(); 686 687 // klass name 688 Symbol* name() const { return _name; } 689 void set_name(Symbol* n); 690 691 public: 692 // jvm support 693 virtual jint compute_modifier_flags(TRAPS) const; 694 695 // JVMTI support 696 virtual jint jvmti_class_status() const; 697 698 // Printing 699 virtual void print_on(outputStream* st) const; 700 701 virtual void oop_print_value_on(oop obj, outputStream* st); 702 virtual void oop_print_on (oop obj, outputStream* st); 703 704 virtual const char* internal_name() const = 0; 705 706 // Verification 707 virtual void verify_on(outputStream* st); 708 void verify() { verify_on(tty); } 709 710 #ifndef PRODUCT 711 bool verify_vtable_index(int index); 712 bool verify_itable_index(int index); 713 #endif 714 715 virtual void oop_verify_on(oop obj, outputStream* st); 716 717 static bool is_null(narrowKlass obj); 718 static bool is_null(Klass* obj); 719 720 // klass encoding for klass pointer in objects. 721 static narrowKlass encode_klass_not_null(Klass* v); 722 static narrowKlass encode_klass(Klass* v); 723 724 static Klass* decode_klass_not_null(narrowKlass v); 725 static Klass* decode_klass(narrowKlass v); 726 }; 727 728 #endif // SHARE_VM_OOPS_KLASS_HPP