1 /* 2 * Copyright (c) 1997, 2019, 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 "memory/genOopClosures.hpp" 29 #include "memory/iterator.hpp" 30 #include "memory/memRegion.hpp" 31 #include "memory/specialized_oop_closures.hpp" 32 #include "oops/klassPS.hpp" 33 #include "oops/metadata.hpp" 34 #include "oops/oop.hpp" 35 #include "trace/traceMacros.hpp" 36 #include "utilities/accessFlags.hpp" 37 #include "utilities/macros.hpp" 38 #if INCLUDE_ALL_GCS 39 #include "gc_implementation/concurrentMarkSweep/cmsOopClosures.hpp" 40 #include "gc_implementation/g1/g1OopClosures.hpp" 41 #include "gc_implementation/parNew/parOopClosures.hpp" 42 #endif // INCLUDE_ALL_GCS 43 #include "jfr/utilities/jfrLog.hpp" 44 45 // 46 // A Klass provides: 47 // 1: language level class object (method dictionary etc.) 48 // 2: provide vm dispatch behavior for the object 49 // Both functions are combined into one C++ class. 50 51 // One reason for the oop/klass dichotomy in the implementation is 52 // that we don't want a C++ vtbl pointer in every object. Thus, 53 // normal oops don't have any virtual functions. Instead, they 54 // forward all "virtual" functions to their klass, which does have 55 // a vtbl and does the C++ dispatch depending on the object's 56 // actual type. (See oop.inline.hpp for some of the forwarding code.) 57 // ALL FUNCTIONS IMPLEMENTING THIS DISPATCH ARE PREFIXED WITH "oop_"! 58 59 // Klass layout: 60 // [C++ vtbl ptr ] (contained in Metadata) 61 // [layout_helper ] 62 // [super_check_offset ] for fast subtype checks 63 // [name ] 64 // [secondary_super_cache] for fast subtype checks 65 // [secondary_supers ] array of 2ndary supertypes 66 // [primary_supers 0] 67 // [primary_supers 1] 68 // [primary_supers 2] 69 // ... 70 // [primary_supers 7] 71 // [java_mirror ] 72 // [super ] 73 // [subklass ] first subclass 74 // [next_sibling ] link to chain additional subklasses 75 // [next_link ] 76 // [class_loader_data] 77 // [modifier_flags] 78 // [access_flags ] 79 // [last_biased_lock_bulk_revocation_time] (64 bits) 80 // [prototype_header] 81 // [biased_lock_revocation_count] 82 // [_modified_oops] 83 // [_accumulated_modified_oops] 84 // [trace_id] 85 86 87 // Forward declarations. 88 template <class T> class Array; 89 template <class T> class GrowableArray; 90 class ClassLoaderData; 91 class klassVtable; 92 class ParCompactionManager; 93 class KlassSizeStats; 94 class fieldDescriptor; 95 96 class Klass : public Metadata { 97 friend class VMStructs; 98 protected: 99 // note: put frequently-used fields together at start of klass structure 100 // for better cache behavior (may not make much of a difference but sure won't hurt) 101 enum { _primary_super_limit = 8 }; 102 103 // The "layout helper" is a combined descriptor of object layout. 104 // For klasses which are neither instance nor array, the value is zero. 105 // 106 // For instances, layout helper is a positive number, the instance size. 107 // This size is already passed through align_object_size and scaled to bytes. 108 // The low order bit is set if instances of this class cannot be 109 // allocated using the fastpath. 110 // 111 // For arrays, layout helper is a negative number, containing four 112 // distinct bytes, as follows: 113 // MSB:[tag, hsz, ebt, log2(esz)]:LSB 114 // where: 115 // tag is 0x80 if the elements are oops, 0xC0 if non-oops 116 // hsz is array header size in bytes (i.e., offset of first element) 117 // ebt is the BasicType of the elements 118 // esz is the element size in bytes 119 // This packed word is arranged so as to be quickly unpacked by the 120 // various fast paths that use the various subfields. 121 // 122 // The esz bits can be used directly by a SLL instruction, without masking. 123 // 124 // Note that the array-kind tag looks like 0x00 for instance klasses, 125 // since their length in bytes is always less than 24Mb. 126 // 127 // Final note: This comes first, immediately after C++ vtable, 128 // because it is frequently queried. 129 jint _layout_helper; 130 131 // The fields _super_check_offset, _secondary_super_cache, _secondary_supers 132 // and _primary_supers all help make fast subtype checks. See big discussion 133 // in doc/server_compiler/checktype.txt 134 // 135 // Where to look to observe a supertype (it is &_secondary_super_cache for 136 // secondary supers, else is &_primary_supers[depth()]. 137 juint _super_check_offset; 138 139 // Class name. Instance classes: java/lang/String, etc. Array classes: [I, 140 // [Ljava/lang/String;, etc. Set to zero for all other kinds of classes. 141 Symbol* _name; 142 143 // Cache of last observed secondary supertype 144 Klass* _secondary_super_cache; 145 // Array of all secondary supertypes 146 Array<Klass*>* _secondary_supers; 147 // Ordered list of all primary supertypes 148 Klass* _primary_supers[_primary_super_limit]; 149 // java/lang/Class instance mirroring this class 150 oop _java_mirror; 151 // Superclass 152 Klass* _super; 153 // First subclass (NULL if none); _subklass->next_sibling() is next one 154 Klass* _subklass; 155 // Sibling link (or NULL); links all subklasses of a klass 156 Klass* _next_sibling; 157 158 // All klasses loaded by a class loader are chained through these links 159 Klass* _next_link; 160 161 // The VM's representation of the ClassLoader used to load this class. 162 // Provide access the corresponding instance java.lang.ClassLoader. 163 ClassLoaderData* _class_loader_data; 164 165 jint _modifier_flags; // Processed access flags, for use by Class.getModifiers. 166 AccessFlags _access_flags; // Access flags. The class/interface distinction is stored here. 167 168 // Biased locking implementation and statistics 169 // (the 64-bit chunk goes first, to avoid some fragmentation) 170 jlong _last_biased_lock_bulk_revocation_time; 171 markOop _prototype_header; // Used when biased locking is both enabled and disabled for this type 172 jint _biased_lock_revocation_count; 173 174 TRACE_DEFINE_TRACE_ID_FIELD; 175 176 // Remembered sets support for the oops in the klasses. 177 jbyte _modified_oops; // Card Table Equivalent (YC/CMS support) 178 jbyte _accumulated_modified_oops; // Mod Union Equivalent (CMS support) 179 180 private: 181 // This is an index into FileMapHeader::_classpath_entry_table[], to 182 // associate this class with the JAR file where it's loaded from during 183 // dump time. If a class is not loaded from the shared archive, this field is 184 // -1. 185 jshort _shared_class_path_index; 186 187 friend class SharedClassUtil; 188 protected: 189 190 // Constructor 191 Klass(); 192 193 void* operator new(size_t size, ClassLoaderData* loader_data, size_t word_size, TRAPS) throw(); 194 195 public: 196 enum DefaultsLookupMode { find_defaults, skip_defaults }; 197 enum OverpassLookupMode { find_overpass, skip_overpass }; 198 enum StaticLookupMode { find_static, skip_static }; 199 enum PrivateLookupMode { find_private, skip_private }; 200 201 bool is_klass() const volatile { return true; } 202 203 // super 204 Klass* super() const { return _super; } 205 void set_super(Klass* k) { _super = k; } 206 207 // initializes _super link, _primary_supers & _secondary_supers arrays 208 void initialize_supers(Klass* k, TRAPS); 209 void initialize_supers_impl1(Klass* k); 210 void initialize_supers_impl2(Klass* k); 211 212 // klass-specific helper for initializing _secondary_supers 213 virtual GrowableArray<Klass*>* compute_secondary_supers(int num_extra_slots); 214 215 // java_super is the Java-level super type as specified by Class.getSuperClass. 216 virtual Klass* java_super() const { return NULL; } 217 218 juint super_check_offset() const { return _super_check_offset; } 219 void set_super_check_offset(juint o) { _super_check_offset = o; } 220 221 Klass* secondary_super_cache() const { return _secondary_super_cache; } 222 void set_secondary_super_cache(Klass* k) { _secondary_super_cache = k; } 223 224 Array<Klass*>* secondary_supers() const { return _secondary_supers; } 225 void set_secondary_supers(Array<Klass*>* k) { _secondary_supers = k; } 226 227 // Return the element of the _super chain of the given depth. 228 // If there is no such element, return either NULL or this. 229 Klass* primary_super_of_depth(juint i) const { 230 assert(i < primary_super_limit(), "oob"); 231 Klass* super = _primary_supers[i]; 232 assert(super == NULL || super->super_depth() == i, "correct display"); 233 return super; 234 } 235 236 // Can this klass be a primary super? False for interfaces and arrays of 237 // interfaces. False also for arrays or classes with long super chains. 238 bool can_be_primary_super() const { 239 const juint secondary_offset = in_bytes(secondary_super_cache_offset()); 240 return super_check_offset() != secondary_offset; 241 } 242 virtual bool can_be_primary_super_slow() const; 243 244 // Returns number of primary supers; may be a number in the inclusive range [0, primary_super_limit]. 245 juint super_depth() const { 246 if (!can_be_primary_super()) { 247 return primary_super_limit(); 248 } else { 249 juint d = (super_check_offset() - in_bytes(primary_supers_offset())) / sizeof(Klass*); 250 assert(d < primary_super_limit(), "oob"); 251 assert(_primary_supers[d] == this, "proper init"); 252 return d; 253 } 254 } 255 256 // store an oop into a field of a Klass 257 void klass_oop_store(oop* p, oop v); 258 void klass_oop_store(volatile oop* p, oop v); 259 260 // java mirror 261 oop java_mirror() const { return _java_mirror; } 262 void set_java_mirror(oop m) { klass_oop_store(&_java_mirror, m); } 263 264 // modifier flags 265 jint modifier_flags() const { return _modifier_flags; } 266 void set_modifier_flags(jint flags) { _modifier_flags = flags; } 267 268 // size helper 269 int layout_helper() const { return _layout_helper; } 270 void set_layout_helper(int lh) { _layout_helper = lh; } 271 272 // Note: for instances layout_helper() may include padding. 273 // Use InstanceKlass::contains_field_offset to classify field offsets. 274 275 // sub/superklass links 276 InstanceKlass* superklass() const; 277 Klass* subklass() const; 278 Klass* next_sibling() const; 279 void append_to_sibling_list(); // add newly created receiver to superklass' subklass list 280 281 void set_next_link(Klass* k) { _next_link = k; } 282 Klass* next_link() const { return _next_link; } // The next klass defined by the class loader. 283 284 // class loader data 285 ClassLoaderData* class_loader_data() const { return _class_loader_data; } 286 void set_class_loader_data(ClassLoaderData* loader_data) { _class_loader_data = loader_data; } 287 288 // The Klasses are not placed in the Heap, so the Card Table or 289 // the Mod Union Table can't be used to mark when klasses have modified oops. 290 // The CT and MUT bits saves this information for the individual Klasses. 291 void record_modified_oops() { _modified_oops = 1; } 292 void clear_modified_oops() { _modified_oops = 0; } 293 bool has_modified_oops() { return _modified_oops == 1; } 294 295 void accumulate_modified_oops() { if (has_modified_oops()) _accumulated_modified_oops = 1; } 296 void clear_accumulated_modified_oops() { _accumulated_modified_oops = 0; } 297 bool has_accumulated_modified_oops() { return _accumulated_modified_oops == 1; } 298 299 int shared_classpath_index() const { 300 return _shared_class_path_index; 301 }; 302 303 void set_shared_classpath_index(int index) { 304 _shared_class_path_index = index; 305 }; 306 307 308 protected: // internal accessors 309 Klass* subklass_oop() const { return _subklass; } 310 Klass* next_sibling_oop() const { return _next_sibling; } 311 void set_subklass(Klass* s); 312 void set_next_sibling(Klass* s); 313 314 public: 315 316 // Compiler support 317 static ByteSize super_offset() { return in_ByteSize(offset_of(Klass, _super)); } 318 static ByteSize super_check_offset_offset() { return in_ByteSize(offset_of(Klass, _super_check_offset)); } 319 static ByteSize primary_supers_offset() { return in_ByteSize(offset_of(Klass, _primary_supers)); } 320 static ByteSize secondary_super_cache_offset() { return in_ByteSize(offset_of(Klass, _secondary_super_cache)); } 321 static ByteSize secondary_supers_offset() { return in_ByteSize(offset_of(Klass, _secondary_supers)); } 322 static ByteSize java_mirror_offset() { return in_ByteSize(offset_of(Klass, _java_mirror)); } 323 static ByteSize modifier_flags_offset() { return in_ByteSize(offset_of(Klass, _modifier_flags)); } 324 static ByteSize layout_helper_offset() { return in_ByteSize(offset_of(Klass, _layout_helper)); } 325 static ByteSize access_flags_offset() { return in_ByteSize(offset_of(Klass, _access_flags)); } 326 327 // Unpacking layout_helper: 328 enum { 329 _lh_neutral_value = 0, // neutral non-array non-instance value 330 _lh_instance_slow_path_bit = 0x01, 331 _lh_log2_element_size_shift = BitsPerByte*0, 332 _lh_log2_element_size_mask = BitsPerLong-1, 333 _lh_element_type_shift = BitsPerByte*1, 334 _lh_element_type_mask = right_n_bits(BitsPerByte), // shifted mask 335 _lh_header_size_shift = BitsPerByte*2, 336 _lh_header_size_mask = right_n_bits(BitsPerByte), // shifted mask 337 _lh_array_tag_bits = 2, 338 _lh_array_tag_shift = BitsPerInt - _lh_array_tag_bits, 339 _lh_array_tag_type_value = ~0x00, // 0xC0000000 >> 30 340 _lh_array_tag_obj_value = ~0x01 // 0x80000000 >> 30 341 }; 342 343 static int layout_helper_size_in_bytes(jint lh) { 344 assert(lh > (jint)_lh_neutral_value, "must be instance"); 345 return (int) lh & ~_lh_instance_slow_path_bit; 346 } 347 static bool layout_helper_needs_slow_path(jint lh) { 348 assert(lh > (jint)_lh_neutral_value, "must be instance"); 349 return (lh & _lh_instance_slow_path_bit) != 0; 350 } 351 static bool layout_helper_is_instance(jint lh) { 352 return (jint)lh > (jint)_lh_neutral_value; 353 } 354 static bool layout_helper_is_array(jint lh) { 355 return (jint)lh < (jint)_lh_neutral_value; 356 } 357 static bool layout_helper_is_typeArray(jint lh) { 358 // _lh_array_tag_type_value == (lh >> _lh_array_tag_shift); 359 return (juint)lh >= (juint)(_lh_array_tag_type_value << _lh_array_tag_shift); 360 } 361 static bool layout_helper_is_objArray(jint lh) { 362 // _lh_array_tag_obj_value == (lh >> _lh_array_tag_shift); 363 return (jint)lh < (jint)(_lh_array_tag_type_value << _lh_array_tag_shift); 364 } 365 static int layout_helper_header_size(jint lh) { 366 assert(lh < (jint)_lh_neutral_value, "must be array"); 367 int hsize = (lh >> _lh_header_size_shift) & _lh_header_size_mask; 368 assert(hsize > 0 && hsize < (int)sizeof(oopDesc)*3, "sanity"); 369 return hsize; 370 } 371 static BasicType layout_helper_element_type(jint lh) { 372 assert(lh < (jint)_lh_neutral_value, "must be array"); 373 int btvalue = (lh >> _lh_element_type_shift) & _lh_element_type_mask; 374 assert(btvalue >= T_BOOLEAN && btvalue <= T_OBJECT, "sanity"); 375 return (BasicType) btvalue; 376 } 377 378 // Want a pattern to quickly diff against layout header in register 379 // find something less clever! 380 static int layout_helper_boolean_diffbit() { 381 jint zlh = array_layout_helper(T_BOOLEAN); 382 jint blh = array_layout_helper(T_BYTE); 383 assert(zlh != blh, "array layout helpers must differ"); 384 int diffbit = 1; 385 while ((diffbit & (zlh ^ blh)) == 0 && (diffbit & zlh) == 0) { 386 diffbit <<= 1; 387 assert(diffbit != 0, "make sure T_BOOLEAN has a different bit than T_BYTE"); 388 } 389 return diffbit; 390 } 391 392 static int layout_helper_log2_element_size(jint lh) { 393 assert(lh < (jint)_lh_neutral_value, "must be array"); 394 int l2esz = (lh >> _lh_log2_element_size_shift) & _lh_log2_element_size_mask; 395 assert(l2esz <= LogBitsPerLong, 396 err_msg("sanity. l2esz: 0x%x for lh: 0x%x", (uint)l2esz, (uint)lh)); 397 return l2esz; 398 } 399 static jint array_layout_helper(jint tag, int hsize, BasicType etype, int log2_esize) { 400 return (tag << _lh_array_tag_shift) 401 | (hsize << _lh_header_size_shift) 402 | ((int)etype << _lh_element_type_shift) 403 | (log2_esize << _lh_log2_element_size_shift); 404 } 405 static jint instance_layout_helper(jint size, bool slow_path_flag) { 406 return (size << LogHeapWordSize) 407 | (slow_path_flag ? _lh_instance_slow_path_bit : 0); 408 } 409 static int layout_helper_to_size_helper(jint lh) { 410 assert(lh > (jint)_lh_neutral_value, "must be instance"); 411 // Note that the following expression discards _lh_instance_slow_path_bit. 412 return lh >> LogHeapWordSize; 413 } 414 // Out-of-line version computes everything based on the etype: 415 static jint array_layout_helper(BasicType etype); 416 417 // What is the maximum number of primary superclasses any klass can have? 418 #ifdef PRODUCT 419 static juint primary_super_limit() { return _primary_super_limit; } 420 #else 421 static juint primary_super_limit() { 422 assert(FastSuperclassLimit <= _primary_super_limit, "parameter oob"); 423 return FastSuperclassLimit; 424 } 425 #endif 426 427 // vtables 428 virtual klassVtable* vtable() const { return NULL; } 429 virtual int vtable_length() const { return 0; } 430 431 // subclass check 432 bool is_subclass_of(const Klass* k) const; 433 // subtype check: true if is_subclass_of, or if k is interface and receiver implements it 434 bool is_subtype_of(Klass* k) const { 435 juint off = k->super_check_offset(); 436 Klass* sup = *(Klass**)( (address)this + off ); 437 const juint secondary_offset = in_bytes(secondary_super_cache_offset()); 438 if (sup == k) { 439 return true; 440 } else if (off != secondary_offset) { 441 return false; 442 } else { 443 return search_secondary_supers(k); 444 } 445 } 446 bool search_secondary_supers(Klass* k) const; 447 448 // Find LCA in class hierarchy 449 Klass *LCA( Klass *k ); 450 451 // Check whether reflection/jni/jvm code is allowed to instantiate this class; 452 // if not, throw either an Error or an Exception. 453 virtual void check_valid_for_instantiation(bool throwError, TRAPS); 454 455 // array copying 456 virtual void copy_array(arrayOop s, int src_pos, arrayOop d, int dst_pos, int length, TRAPS); 457 458 // tells if the class should be initialized 459 virtual bool should_be_initialized() const { return false; } 460 // initializes the klass 461 virtual void initialize(TRAPS); 462 // lookup operation for MethodLookupCache 463 friend class MethodLookupCache; 464 virtual Klass* find_field(Symbol* name, Symbol* signature, fieldDescriptor* fd) const; 465 virtual Method* uncached_lookup_method(Symbol* name, Symbol* signature, OverpassLookupMode overpass_mode) const; 466 public: 467 Method* lookup_method(Symbol* name, Symbol* signature) const { 468 return uncached_lookup_method(name, signature, find_overpass); 469 } 470 471 // array class with specific rank 472 Klass* array_klass(int rank, TRAPS) { return array_klass_impl(false, rank, THREAD); } 473 474 // array class with this klass as element type 475 Klass* array_klass(TRAPS) { return array_klass_impl(false, THREAD); } 476 477 // These will return NULL instead of allocating on the heap: 478 // NB: these can block for a mutex, like other functions with TRAPS arg. 479 Klass* array_klass_or_null(int rank); 480 Klass* array_klass_or_null(); 481 482 virtual oop protection_domain() const = 0; 483 484 oop class_loader() const; 485 486 virtual oop klass_holder() const { return class_loader(); } 487 488 protected: 489 virtual Klass* array_klass_impl(bool or_null, int rank, TRAPS); 490 virtual Klass* array_klass_impl(bool or_null, TRAPS); 491 492 public: 493 // CDS support - remove and restore oops from metadata. Oops are not shared. 494 virtual void remove_unshareable_info(); 495 virtual void restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS); 496 497 protected: 498 // computes the subtype relationship 499 virtual bool compute_is_subtype_of(Klass* k); 500 public: 501 // subclass accessor (here for convenience; undefined for non-klass objects) 502 virtual bool is_leaf_class() const { fatal("not a class"); return false; } 503 public: 504 // ALL FUNCTIONS BELOW THIS POINT ARE DISPATCHED FROM AN OOP 505 // These functions describe behavior for the oop not the KLASS. 506 507 // actual oop size of obj in memory 508 virtual int oop_size(oop obj) const = 0; 509 510 // Size of klass in word size. 511 virtual int size() const = 0; 512 #if INCLUDE_SERVICES 513 virtual void collect_statistics(KlassSizeStats *sz) const; 514 #endif 515 516 // Returns the Java name for a class (Resource allocated) 517 // For arrays, this returns the name of the element with a leading '['. 518 // For classes, this returns the name with the package separators 519 // turned into '.'s. 520 const char* external_name() const; 521 // Returns the name for a class (Resource allocated) as the class 522 // would appear in a signature. 523 // For arrays, this returns the name of the element with a leading '['. 524 // For classes, this returns the name with a leading 'L' and a trailing ';' 525 // and the package separators as '/'. 526 virtual const char* signature_name() const; 527 528 // garbage collection support 529 virtual void oop_follow_contents(oop obj) = 0; 530 virtual int oop_adjust_pointers(oop obj) = 0; 531 532 // Parallel Scavenge and Parallel Old 533 PARALLEL_GC_DECLS_PV 534 535 // type testing operations 536 protected: 537 virtual bool oop_is_instance_slow() const { return false; } 538 virtual bool oop_is_array_slow() const { return false; } 539 virtual bool oop_is_objArray_slow() const { return false; } 540 virtual bool oop_is_typeArray_slow() const { return false; } 541 public: 542 virtual bool oop_is_instanceClassLoader() const { return false; } 543 virtual bool oop_is_instanceMirror() const { return false; } 544 virtual bool oop_is_instanceRef() const { return false; } 545 546 // Fast non-virtual versions 547 #ifndef ASSERT 548 #define assert_same_query(xval, xcheck) xval 549 #else 550 private: 551 static bool assert_same_query(bool xval, bool xslow) { 552 assert(xval == xslow, "slow and fast queries agree"); 553 return xval; 554 } 555 public: 556 #endif 557 inline bool oop_is_instance() const { return assert_same_query( 558 layout_helper_is_instance(layout_helper()), 559 oop_is_instance_slow()); } 560 inline bool oop_is_array() const { return assert_same_query( 561 layout_helper_is_array(layout_helper()), 562 oop_is_array_slow()); } 563 inline bool oop_is_objArray() const { return assert_same_query( 564 layout_helper_is_objArray(layout_helper()), 565 oop_is_objArray_slow()); } 566 inline bool oop_is_typeArray() const { return assert_same_query( 567 layout_helper_is_typeArray(layout_helper()), 568 oop_is_typeArray_slow()); } 569 #undef assert_same_query 570 571 // Access flags 572 AccessFlags access_flags() const { return _access_flags; } 573 void set_access_flags(AccessFlags flags) { _access_flags = flags; } 574 575 bool is_public() const { return _access_flags.is_public(); } 576 bool is_final() const { return _access_flags.is_final(); } 577 bool is_interface() const { return _access_flags.is_interface(); } 578 bool is_abstract() const { return _access_flags.is_abstract(); } 579 bool is_super() const { return _access_flags.is_super(); } 580 bool is_synthetic() const { return _access_flags.is_synthetic(); } 581 void set_is_synthetic() { _access_flags.set_is_synthetic(); } 582 bool has_finalizer() const { return _access_flags.has_finalizer(); } 583 bool has_final_method() const { return _access_flags.has_final_method(); } 584 void set_has_finalizer() { _access_flags.set_has_finalizer(); } 585 void set_has_final_method() { _access_flags.set_has_final_method(); } 586 bool is_cloneable() const; 587 void set_is_cloneable(); 588 bool has_vanilla_constructor() const { return _access_flags.has_vanilla_constructor(); } 589 void set_has_vanilla_constructor() { _access_flags.set_has_vanilla_constructor(); } 590 bool has_miranda_methods () const { return access_flags().has_miranda_methods(); } 591 void set_has_miranda_methods() { _access_flags.set_has_miranda_methods(); } 592 593 // Biased locking support 594 // Note: the prototype header is always set up to be at least the 595 // prototype markOop. If biased locking is enabled it may further be 596 // biasable and have an epoch. 597 markOop prototype_header() const { return _prototype_header; } 598 // NOTE: once instances of this klass are floating around in the 599 // system, this header must only be updated at a safepoint. 600 // NOTE 2: currently we only ever set the prototype header to the 601 // biasable prototype for instanceKlasses. There is no technical 602 // reason why it could not be done for arrayKlasses aside from 603 // wanting to reduce the initial scope of this optimization. There 604 // are potential problems in setting the bias pattern for 605 // JVM-internal oops. 606 inline void set_prototype_header(markOop header); 607 static ByteSize prototype_header_offset() { return in_ByteSize(offset_of(Klass, _prototype_header)); } 608 609 int biased_lock_revocation_count() const { return (int) _biased_lock_revocation_count; } 610 // Atomically increments biased_lock_revocation_count and returns updated value 611 int atomic_incr_biased_lock_revocation_count(); 612 void set_biased_lock_revocation_count(int val) { _biased_lock_revocation_count = (jint) val; } 613 jlong last_biased_lock_bulk_revocation_time() { return _last_biased_lock_bulk_revocation_time; } 614 void set_last_biased_lock_bulk_revocation_time(jlong cur_time) { _last_biased_lock_bulk_revocation_time = cur_time; } 615 616 TRACE_DEFINE_TRACE_ID_METHODS; 617 618 // garbage collection support 619 virtual void oops_do(OopClosure* cl); 620 621 // Iff the class loader (or mirror for anonymous classes) is alive the 622 // Klass is considered alive. 623 // The is_alive closure passed in depends on the Garbage Collector used. 624 bool is_loader_alive(BoolObjectClosure* is_alive); 625 626 static void clean_weak_klass_links(BoolObjectClosure* is_alive, bool clean_alive_klasses = true); 627 static void clean_subklass_tree(BoolObjectClosure* is_alive) { 628 clean_weak_klass_links(is_alive, false /* clean_alive_klasses */); 629 } 630 631 // iterators 632 virtual int oop_oop_iterate(oop obj, ExtendedOopClosure* blk) = 0; 633 virtual int oop_oop_iterate_v(oop obj, ExtendedOopClosure* blk) { 634 return oop_oop_iterate(obj, blk); 635 } 636 637 #if INCLUDE_ALL_GCS 638 // In case we don't have a specialized backward scanner use forward 639 // iteration. 640 virtual int oop_oop_iterate_backwards_v(oop obj, ExtendedOopClosure* blk) { 641 return oop_oop_iterate_v(obj, blk); 642 } 643 #endif // INCLUDE_ALL_GCS 644 645 // Iterates "blk" over all the oops in "obj" (of type "this") within "mr". 646 // (I don't see why the _m should be required, but without it the Solaris 647 // C++ gives warning messages about overridings of the "oop_oop_iterate" 648 // defined above "hiding" this virtual function. (DLD, 6/20/00)) */ 649 virtual int oop_oop_iterate_m(oop obj, ExtendedOopClosure* blk, MemRegion mr) = 0; 650 virtual int oop_oop_iterate_v_m(oop obj, ExtendedOopClosure* blk, MemRegion mr) { 651 return oop_oop_iterate_m(obj, blk, mr); 652 } 653 654 // Versions of the above iterators specialized to particular subtypes 655 // of OopClosure, to avoid closure virtual calls. 656 #define Klass_OOP_OOP_ITERATE_DECL(OopClosureType, nv_suffix) \ 657 virtual int oop_oop_iterate##nv_suffix(oop obj, OopClosureType* blk) { \ 658 /* Default implementation reverts to general version. */ \ 659 return oop_oop_iterate(obj, blk); \ 660 } \ 661 \ 662 /* Iterates "blk" over all the oops in "obj" (of type "this") within "mr". \ 663 (I don't see why the _m should be required, but without it the Solaris \ 664 C++ gives warning messages about overridings of the "oop_oop_iterate" \ 665 defined above "hiding" this virtual function. (DLD, 6/20/00)) */ \ 666 virtual int oop_oop_iterate##nv_suffix##_m(oop obj, \ 667 OopClosureType* blk, \ 668 MemRegion mr) { \ 669 return oop_oop_iterate_m(obj, blk, mr); \ 670 } 671 672 SPECIALIZED_OOP_OOP_ITERATE_CLOSURES_1(Klass_OOP_OOP_ITERATE_DECL) 673 SPECIALIZED_OOP_OOP_ITERATE_CLOSURES_2(Klass_OOP_OOP_ITERATE_DECL) 674 675 #if INCLUDE_ALL_GCS 676 #define Klass_OOP_OOP_ITERATE_BACKWARDS_DECL(OopClosureType, nv_suffix) \ 677 virtual int oop_oop_iterate_backwards##nv_suffix(oop obj, \ 678 OopClosureType* blk) { \ 679 /* Default implementation reverts to general version. */ \ 680 return oop_oop_iterate_backwards_v(obj, blk); \ 681 } 682 683 SPECIALIZED_OOP_OOP_ITERATE_CLOSURES_1(Klass_OOP_OOP_ITERATE_BACKWARDS_DECL) 684 SPECIALIZED_OOP_OOP_ITERATE_CLOSURES_2(Klass_OOP_OOP_ITERATE_BACKWARDS_DECL) 685 #endif // INCLUDE_ALL_GCS 686 687 virtual void array_klasses_do(void f(Klass* k)) {} 688 689 // Return self, except for abstract classes with exactly 1 690 // implementor. Then return the 1 concrete implementation. 691 Klass *up_cast_abstract(); 692 693 // klass name 694 Symbol* name() const { return _name; } 695 void set_name(Symbol* n); 696 697 public: 698 // jvm support 699 virtual jint compute_modifier_flags(TRAPS) const; 700 701 // JVMTI support 702 virtual jint jvmti_class_status() const; 703 704 // Printing 705 virtual void print_on(outputStream* st) const; 706 707 virtual void oop_print_value_on(oop obj, outputStream* st); 708 virtual void oop_print_on (oop obj, outputStream* st); 709 710 virtual const char* internal_name() const = 0; 711 712 // Verification 713 virtual void verify_on(outputStream* st); 714 void verify() { verify_on(tty); } 715 716 #ifndef PRODUCT 717 bool verify_vtable_index(int index); 718 bool verify_itable_index(int index); 719 #endif 720 721 virtual void oop_verify_on(oop obj, outputStream* st); 722 723 static bool is_null(narrowKlass obj); 724 static bool is_null(Klass* obj); 725 726 // klass encoding for klass pointer in objects. 727 static narrowKlass encode_klass_not_null(Klass* v); 728 static narrowKlass encode_klass(Klass* v); 729 730 static Klass* decode_klass_not_null(narrowKlass v); 731 static Klass* decode_klass(narrowKlass v); 732 733 private: 734 // barriers used by klass_oop_store 735 void klass_update_barrier_set(oop v); 736 void klass_update_barrier_set_pre(oop* p, oop v); 737 }; 738 739 #endif // SHARE_VM_OOPS_KLASS_HPP