1 /* 2 * Copyright (c) 1997, 2017, 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 "gc/shared/specialized_oop_closures.hpp" 29 #include "memory/iterator.hpp" 30 #include "memory/memRegion.hpp" 31 #include "oops/metadata.hpp" 32 #include "oops/oop.hpp" 33 #include "trace/traceMacros.hpp" 34 #include "utilities/accessFlags.hpp" 35 #include "utilities/macros.hpp" 36 37 // 38 // A Klass provides: 39 // 1: language level class object (method dictionary etc.) 40 // 2: provide vm dispatch behavior for the object 41 // Both functions are combined into one C++ class. 42 43 // One reason for the oop/klass dichotomy in the implementation is 44 // that we don't want a C++ vtbl pointer in every object. Thus, 45 // normal oops don't have any virtual functions. Instead, they 46 // forward all "virtual" functions to their klass, which does have 47 // a vtbl and does the C++ dispatch depending on the object's 48 // actual type. (See oop.inline.hpp for some of the forwarding code.) 49 // ALL FUNCTIONS IMPLEMENTING THIS DISPATCH ARE PREFIXED WITH "oop_"! 50 51 // Forward declarations. 52 template <class T> class Array; 53 template <class T> class GrowableArray; 54 class ClassLoaderData; 55 class fieldDescriptor; 56 class KlassSizeStats; 57 class klassVtable; 58 class ModuleEntry; 59 class PackageEntry; 60 class ParCompactionManager; 61 class PSPromotionManager; 62 class vtableEntry; 63 64 class Klass : public Metadata { 65 friend class VMStructs; 66 friend class JVMCIVMStructs; 67 protected: 68 // note: put frequently-used fields together at start of klass structure 69 // for better cache behavior (may not make much of a difference but sure won't hurt) 70 enum { _primary_super_limit = 8 }; 71 72 // The "layout helper" is a combined descriptor of object layout. 73 // For klasses which are neither instance nor array, the value is zero. 74 // 75 // For instances, layout helper is a positive number, the instance size. 76 // This size is already passed through align_object_size and scaled to bytes. 77 // The low order bit is set if instances of this class cannot be 78 // allocated using the fastpath. 79 // 80 // For arrays, layout helper is a negative number, containing four 81 // distinct bytes, as follows: 82 // MSB:[tag, hsz, ebt, log2(esz)]:LSB 83 // where: 84 // tag is 0x80 if the elements are oops, 0xC0 if non-oops 85 // hsz is array header size in bytes (i.e., offset of first element) 86 // ebt is the BasicType of the elements 87 // esz is the element size in bytes 88 // This packed word is arranged so as to be quickly unpacked by the 89 // various fast paths that use the various subfields. 90 // 91 // The esz bits can be used directly by a SLL instruction, without masking. 92 // 93 // Note that the array-kind tag looks like 0x00 for instance klasses, 94 // since their length in bytes is always less than 24Mb. 95 // 96 // Final note: This comes first, immediately after C++ vtable, 97 // because it is frequently queried. 98 jint _layout_helper; 99 100 // The fields _super_check_offset, _secondary_super_cache, _secondary_supers 101 // and _primary_supers all help make fast subtype checks. See big discussion 102 // in doc/server_compiler/checktype.txt 103 // 104 // Where to look to observe a supertype (it is &_secondary_super_cache for 105 // secondary supers, else is &_primary_supers[depth()]. 106 juint _super_check_offset; 107 108 // Class name. Instance classes: java/lang/String, etc. Array classes: [I, 109 // [Ljava/lang/String;, etc. Set to zero for all other kinds of classes. 110 Symbol* _name; 111 112 // Cache of last observed secondary supertype 113 Klass* _secondary_super_cache; 114 // Array of all secondary supertypes 115 Array<Klass*>* _secondary_supers; 116 // Ordered list of all primary supertypes 117 Klass* _primary_supers[_primary_super_limit]; 118 // java/lang/Class instance mirroring this class 119 oop _java_mirror; 120 // Superclass 121 Klass* _super; 122 // First subclass (NULL if none); _subklass->next_sibling() is next one 123 Klass* _subklass; 124 // Sibling link (or NULL); links all subklasses of a klass 125 Klass* _next_sibling; 126 127 // All klasses loaded by a class loader are chained through these links 128 Klass* _next_link; 129 130 // The VM's representation of the ClassLoader used to load this class. 131 // Provide access the corresponding instance java.lang.ClassLoader. 132 ClassLoaderData* _class_loader_data; 133 134 jint _modifier_flags; // Processed access flags, for use by Class.getModifiers. 135 AccessFlags _access_flags; // Access flags. The class/interface distinction is stored here. 136 137 TRACE_DEFINE_TRACE_ID_FIELD; 138 139 // Biased locking implementation and statistics 140 // (the 64-bit chunk goes first, to avoid some fragmentation) 141 jlong _last_biased_lock_bulk_revocation_time; 142 markOop _prototype_header; // Used when biased locking is both enabled and disabled for this type 143 jint _biased_lock_revocation_count; 144 145 // vtable length 146 int _vtable_len; 147 148 // Remembered sets support for the oops in the klasses. 149 jbyte _modified_oops; // Card Table Equivalent (YC/CMS support) 150 jbyte _accumulated_modified_oops; // Mod Union Equivalent (CMS support) 151 152 private: 153 // This is an index into FileMapHeader::_classpath_entry_table[], to 154 // associate this class with the JAR file where it's loaded from during 155 // dump time. If a class is not loaded from the shared archive, this field is 156 // -1. 157 jshort _shared_class_path_index; 158 159 friend class SharedClassUtil; 160 protected: 161 162 // Constructor 163 Klass(); 164 165 void* operator new(size_t size, ClassLoaderData* loader_data, size_t word_size, TRAPS) throw(); 166 167 public: 168 enum DefaultsLookupMode { find_defaults, skip_defaults }; 169 enum OverpassLookupMode { find_overpass, skip_overpass }; 170 enum StaticLookupMode { find_static, skip_static }; 171 enum PrivateLookupMode { find_private, skip_private }; 172 173 bool is_klass() const volatile { return true; } 174 175 // super 176 Klass* super() const { return _super; } 177 void set_super(Klass* k) { _super = k; } 178 179 // initializes _super link, _primary_supers & _secondary_supers arrays 180 void initialize_supers(Klass* k, TRAPS); 181 void initialize_supers_impl1(Klass* k); 182 void initialize_supers_impl2(Klass* k); 183 184 // klass-specific helper for initializing _secondary_supers 185 virtual GrowableArray<Klass*>* compute_secondary_supers(int num_extra_slots); 186 187 // java_super is the Java-level super type as specified by Class.getSuperClass. 188 virtual Klass* java_super() const { return NULL; } 189 190 juint super_check_offset() const { return _super_check_offset; } 191 void set_super_check_offset(juint o) { _super_check_offset = o; } 192 193 Klass* secondary_super_cache() const { return _secondary_super_cache; } 194 void set_secondary_super_cache(Klass* k) { _secondary_super_cache = k; } 195 196 Array<Klass*>* secondary_supers() const { return _secondary_supers; } 197 void set_secondary_supers(Array<Klass*>* k) { _secondary_supers = k; } 198 199 // Return the element of the _super chain of the given depth. 200 // If there is no such element, return either NULL or this. 201 Klass* primary_super_of_depth(juint i) const { 202 assert(i < primary_super_limit(), "oob"); 203 Klass* super = _primary_supers[i]; 204 assert(super == NULL || super->super_depth() == i, "correct display"); 205 return super; 206 } 207 208 // Can this klass be a primary super? False for interfaces and arrays of 209 // interfaces. False also for arrays or classes with long super chains. 210 bool can_be_primary_super() const { 211 const juint secondary_offset = in_bytes(secondary_super_cache_offset()); 212 return super_check_offset() != secondary_offset; 213 } 214 virtual bool can_be_primary_super_slow() const; 215 216 // Returns number of primary supers; may be a number in the inclusive range [0, primary_super_limit]. 217 juint super_depth() const { 218 if (!can_be_primary_super()) { 219 return primary_super_limit(); 220 } else { 221 juint d = (super_check_offset() - in_bytes(primary_supers_offset())) / sizeof(Klass*); 222 assert(d < primary_super_limit(), "oob"); 223 assert(_primary_supers[d] == this, "proper init"); 224 return d; 225 } 226 } 227 228 // java mirror 229 oop java_mirror() const { return _java_mirror; } 230 void set_java_mirror(oop m); 231 232 // modifier flags 233 jint modifier_flags() const { return _modifier_flags; } 234 void set_modifier_flags(jint flags) { _modifier_flags = flags; } 235 236 // size helper 237 int layout_helper() const { return _layout_helper; } 238 void set_layout_helper(int lh) { _layout_helper = lh; } 239 240 // Note: for instances layout_helper() may include padding. 241 // Use InstanceKlass::contains_field_offset to classify field offsets. 242 243 // sub/superklass links 244 Klass* subklass() const { return _subklass; } 245 Klass* next_sibling() const { return _next_sibling; } 246 InstanceKlass* superklass() const; 247 void append_to_sibling_list(); // add newly created receiver to superklass' subklass list 248 249 void set_next_link(Klass* k) { _next_link = k; } 250 Klass* next_link() const { return _next_link; } // The next klass defined by the class loader. 251 252 // class loader data 253 ClassLoaderData* class_loader_data() const { return _class_loader_data; } 254 void set_class_loader_data(ClassLoaderData* loader_data) { _class_loader_data = loader_data; } 255 256 // The Klasses are not placed in the Heap, so the Card Table or 257 // the Mod Union Table can't be used to mark when klasses have modified oops. 258 // The CT and MUT bits saves this information for the individual Klasses. 259 void record_modified_oops() { _modified_oops = 1; } 260 void clear_modified_oops() { _modified_oops = 0; } 261 bool has_modified_oops() { return _modified_oops == 1; } 262 263 void accumulate_modified_oops() { if (has_modified_oops()) _accumulated_modified_oops = 1; } 264 void clear_accumulated_modified_oops() { _accumulated_modified_oops = 0; } 265 bool has_accumulated_modified_oops() { return _accumulated_modified_oops == 1; } 266 267 int shared_classpath_index() const { 268 return _shared_class_path_index; 269 }; 270 271 void set_shared_classpath_index(int index) { 272 _shared_class_path_index = index; 273 }; 274 275 // Obtain the module or package for this class 276 virtual ModuleEntry* module() const = 0; 277 virtual PackageEntry* package() const = 0; 278 279 protected: // internal accessors 280 void set_subklass(Klass* s); 281 void set_next_sibling(Klass* s); 282 283 public: 284 285 // Compiler support 286 static ByteSize super_offset() { return in_ByteSize(offset_of(Klass, _super)); } 287 static ByteSize super_check_offset_offset() { return in_ByteSize(offset_of(Klass, _super_check_offset)); } 288 static ByteSize primary_supers_offset() { return in_ByteSize(offset_of(Klass, _primary_supers)); } 289 static ByteSize secondary_super_cache_offset() { return in_ByteSize(offset_of(Klass, _secondary_super_cache)); } 290 static ByteSize secondary_supers_offset() { return in_ByteSize(offset_of(Klass, _secondary_supers)); } 291 static ByteSize java_mirror_offset() { return in_ByteSize(offset_of(Klass, _java_mirror)); } 292 static ByteSize modifier_flags_offset() { return in_ByteSize(offset_of(Klass, _modifier_flags)); } 293 static ByteSize layout_helper_offset() { return in_ByteSize(offset_of(Klass, _layout_helper)); } 294 static ByteSize access_flags_offset() { return in_ByteSize(offset_of(Klass, _access_flags)); } 295 296 // Unpacking layout_helper: 297 enum { 298 _lh_neutral_value = 0, // neutral non-array non-instance value 299 _lh_instance_slow_path_bit = 0x01, 300 _lh_log2_element_size_shift = BitsPerByte*0, 301 _lh_log2_element_size_mask = BitsPerLong-1, 302 _lh_element_type_shift = BitsPerByte*1, 303 _lh_element_type_mask = right_n_bits(BitsPerByte), // shifted mask 304 _lh_header_size_shift = BitsPerByte*2, 305 _lh_header_size_mask = right_n_bits(BitsPerByte), // shifted mask 306 _lh_array_tag_bits = 2, 307 _lh_array_tag_shift = BitsPerInt - _lh_array_tag_bits, 308 _lh_array_tag_obj_value = ~0x01 // 0x80000000 >> 30 309 }; 310 311 static const unsigned int _lh_array_tag_type_value = 0Xffffffff; // ~0x00, // 0xC0000000 >> 30 312 313 static int layout_helper_size_in_bytes(jint lh) { 314 assert(lh > (jint)_lh_neutral_value, "must be instance"); 315 return (int) lh & ~_lh_instance_slow_path_bit; 316 } 317 static bool layout_helper_needs_slow_path(jint lh) { 318 assert(lh > (jint)_lh_neutral_value, "must be instance"); 319 return (lh & _lh_instance_slow_path_bit) != 0; 320 } 321 static bool layout_helper_is_instance(jint lh) { 322 return (jint)lh > (jint)_lh_neutral_value; 323 } 324 static bool layout_helper_is_array(jint lh) { 325 return (jint)lh < (jint)_lh_neutral_value; 326 } 327 static bool layout_helper_is_typeArray(jint lh) { 328 // _lh_array_tag_type_value == (lh >> _lh_array_tag_shift); 329 return (juint)lh >= (juint)(_lh_array_tag_type_value << _lh_array_tag_shift); 330 } 331 static bool layout_helper_is_objArray(jint lh) { 332 // _lh_array_tag_obj_value == (lh >> _lh_array_tag_shift); 333 return (jint)lh < (jint)(_lh_array_tag_type_value << _lh_array_tag_shift); 334 } 335 static int layout_helper_header_size(jint lh) { 336 assert(lh < (jint)_lh_neutral_value, "must be array"); 337 int hsize = (lh >> _lh_header_size_shift) & _lh_header_size_mask; 338 assert(hsize > 0 && hsize < (int)sizeof(oopDesc)*3, "sanity"); 339 return hsize; 340 } 341 static BasicType layout_helper_element_type(jint lh) { 342 assert(lh < (jint)_lh_neutral_value, "must be array"); 343 int btvalue = (lh >> _lh_element_type_shift) & _lh_element_type_mask; 344 assert(btvalue >= T_BOOLEAN && btvalue <= T_OBJECT, "sanity"); 345 return (BasicType) btvalue; 346 } 347 348 // Want a pattern to quickly diff against layout header in register 349 // find something less clever! 350 static int layout_helper_boolean_diffbit() { 351 jint zlh = array_layout_helper(T_BOOLEAN); 352 jint blh = array_layout_helper(T_BYTE); 353 assert(zlh != blh, "array layout helpers must differ"); 354 int diffbit = 1; 355 while ((diffbit & (zlh ^ blh)) == 0 && (diffbit & zlh) == 0) { 356 diffbit <<= 1; 357 assert(diffbit != 0, "make sure T_BOOLEAN has a different bit than T_BYTE"); 358 } 359 return diffbit; 360 } 361 362 static int layout_helper_log2_element_size(jint lh) { 363 assert(lh < (jint)_lh_neutral_value, "must be array"); 364 int l2esz = (lh >> _lh_log2_element_size_shift) & _lh_log2_element_size_mask; 365 assert(l2esz <= LogBitsPerLong, 366 "sanity. l2esz: 0x%x for lh: 0x%x", (uint)l2esz, (uint)lh); 367 return l2esz; 368 } 369 static jint array_layout_helper(jint tag, int hsize, BasicType etype, int log2_esize) { 370 return (tag << _lh_array_tag_shift) 371 | (hsize << _lh_header_size_shift) 372 | ((int)etype << _lh_element_type_shift) 373 | (log2_esize << _lh_log2_element_size_shift); 374 } 375 static jint instance_layout_helper(jint size, bool slow_path_flag) { 376 return (size << LogBytesPerWord) 377 | (slow_path_flag ? _lh_instance_slow_path_bit : 0); 378 } 379 static int layout_helper_to_size_helper(jint lh) { 380 assert(lh > (jint)_lh_neutral_value, "must be instance"); 381 // Note that the following expression discards _lh_instance_slow_path_bit. 382 return lh >> LogBytesPerWord; 383 } 384 // Out-of-line version computes everything based on the etype: 385 static jint array_layout_helper(BasicType etype); 386 387 // What is the maximum number of primary superclasses any klass can have? 388 #ifdef PRODUCT 389 static juint primary_super_limit() { return _primary_super_limit; } 390 #else 391 static juint primary_super_limit() { 392 assert(FastSuperclassLimit <= _primary_super_limit, "parameter oob"); 393 return FastSuperclassLimit; 394 } 395 #endif 396 397 // vtables 398 klassVtable vtable() const; 399 int vtable_length() const { return _vtable_len; } 400 401 // subclass check 402 bool is_subclass_of(const Klass* k) const; 403 // subtype check: true if is_subclass_of, or if k is interface and receiver implements it 404 bool is_subtype_of(Klass* k) const { 405 juint off = k->super_check_offset(); 406 Klass* sup = *(Klass**)( (address)this + off ); 407 const juint secondary_offset = in_bytes(secondary_super_cache_offset()); 408 if (sup == k) { 409 return true; 410 } else if (off != secondary_offset) { 411 return false; 412 } else { 413 return search_secondary_supers(k); 414 } 415 } 416 bool search_secondary_supers(Klass* k) const; 417 418 // Find LCA in class hierarchy 419 Klass *LCA( Klass *k ); 420 421 // Check whether reflection/jni/jvm code is allowed to instantiate this class; 422 // if not, throw either an Error or an Exception. 423 virtual void check_valid_for_instantiation(bool throwError, TRAPS); 424 425 // array copying 426 virtual void copy_array(arrayOop s, int src_pos, arrayOop d, int dst_pos, int length, TRAPS); 427 428 // tells if the class should be initialized 429 virtual bool should_be_initialized() const { return false; } 430 // initializes the klass 431 virtual void initialize(TRAPS); 432 // lookup operation for MethodLookupCache 433 friend class MethodLookupCache; 434 virtual Klass* find_field(Symbol* name, Symbol* signature, fieldDescriptor* fd) const; 435 virtual Method* uncached_lookup_method(const Symbol* name, const Symbol* signature, OverpassLookupMode overpass_mode) const; 436 437 virtual oop* klass_holder_addr() const; 438 public: 439 Method* lookup_method(const Symbol* name, const Symbol* signature) const { 440 return uncached_lookup_method(name, signature, find_overpass); 441 } 442 443 // array class with specific rank 444 Klass* array_klass(int rank, TRAPS) { return array_klass_impl(false, rank, THREAD); } 445 446 // array class with this klass as element type 447 Klass* array_klass(TRAPS) { return array_klass_impl(false, THREAD); } 448 449 // These will return NULL instead of allocating on the heap: 450 // NB: these can block for a mutex, like other functions with TRAPS arg. 451 Klass* array_klass_or_null(int rank); 452 Klass* array_klass_or_null(); 453 454 virtual oop protection_domain() const = 0; 455 456 oop class_loader() const; 457 458 oop klass_holder() const; 459 460 protected: 461 virtual Klass* array_klass_impl(bool or_null, int rank, TRAPS); 462 virtual Klass* array_klass_impl(bool or_null, TRAPS); 463 464 void set_vtable_length(int len) { _vtable_len= len; } 465 466 vtableEntry* start_of_vtable() const; 467 public: 468 Method* method_at_vtable(int index); 469 470 static ByteSize vtable_start_offset(); 471 static ByteSize vtable_length_offset() { 472 return byte_offset_of(Klass, _vtable_len); 473 } 474 475 // CDS support - remove and restore oops from metadata. Oops are not shared. 476 virtual void remove_unshareable_info(); 477 virtual void restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS); 478 479 protected: 480 // computes the subtype relationship 481 virtual bool compute_is_subtype_of(Klass* k); 482 public: 483 // subclass accessor (here for convenience; undefined for non-klass objects) 484 virtual bool is_leaf_class() const { fatal("not a class"); return false; } 485 public: 486 // ALL FUNCTIONS BELOW THIS POINT ARE DISPATCHED FROM AN OOP 487 // These functions describe behavior for the oop not the KLASS. 488 489 // actual oop size of obj in memory 490 virtual int oop_size(oop obj) const = 0; 491 492 // Size of klass in word size. 493 virtual int size() const = 0; 494 #if INCLUDE_SERVICES 495 virtual void collect_statistics(KlassSizeStats *sz) const; 496 #endif 497 498 // Returns the Java name for a class (Resource allocated) 499 // For arrays, this returns the name of the element with a leading '['. 500 // For classes, this returns the name with the package separators 501 // turned into '.'s. 502 const char* external_name() const; 503 // Returns the name for a class (Resource allocated) as the class 504 // would appear in a signature. 505 // For arrays, this returns the name of the element with a leading '['. 506 // For classes, this returns the name with a leading 'L' and a trailing ';' 507 // and the package separators as '/'. 508 virtual const char* signature_name() const; 509 510 // type testing operations 511 #ifdef ASSERT 512 protected: 513 virtual bool is_instance_klass_slow() const { return false; } 514 virtual bool is_array_klass_slow() const { return false; } 515 virtual bool is_objArray_klass_slow() const { return false; } 516 virtual bool is_typeArray_klass_slow() const { return false; } 517 #endif // ASSERT 518 public: 519 520 // Fast non-virtual versions 521 #ifndef ASSERT 522 #define assert_same_query(xval, xcheck) xval 523 #else 524 private: 525 static bool assert_same_query(bool xval, bool xslow) { 526 assert(xval == xslow, "slow and fast queries agree"); 527 return xval; 528 } 529 public: 530 #endif 531 inline bool is_instance_klass() const { return assert_same_query( 532 layout_helper_is_instance(layout_helper()), 533 is_instance_klass_slow()); } 534 inline bool is_array_klass() const { return assert_same_query( 535 layout_helper_is_array(layout_helper()), 536 is_array_klass_slow()); } 537 inline bool is_objArray_klass() const { return assert_same_query( 538 layout_helper_is_objArray(layout_helper()), 539 is_objArray_klass_slow()); } 540 inline bool is_typeArray_klass() const { return assert_same_query( 541 layout_helper_is_typeArray(layout_helper()), 542 is_typeArray_klass_slow()); } 543 #undef assert_same_query 544 545 // Access flags 546 AccessFlags access_flags() const { return _access_flags; } 547 void set_access_flags(AccessFlags flags) { _access_flags = flags; } 548 549 bool is_public() const { return _access_flags.is_public(); } 550 bool is_final() const { return _access_flags.is_final(); } 551 bool is_interface() const { return _access_flags.is_interface(); } 552 bool is_abstract() const { return _access_flags.is_abstract(); } 553 bool is_super() const { return _access_flags.is_super(); } 554 bool is_synthetic() const { return _access_flags.is_synthetic(); } 555 void set_is_synthetic() { _access_flags.set_is_synthetic(); } 556 bool has_finalizer() const { return _access_flags.has_finalizer(); } 557 bool has_final_method() const { return _access_flags.has_final_method(); } 558 void set_has_finalizer() { _access_flags.set_has_finalizer(); } 559 void set_has_final_method() { _access_flags.set_has_final_method(); } 560 bool has_vanilla_constructor() const { return _access_flags.has_vanilla_constructor(); } 561 void set_has_vanilla_constructor() { _access_flags.set_has_vanilla_constructor(); } 562 bool has_miranda_methods () const { return access_flags().has_miranda_methods(); } 563 void set_has_miranda_methods() { _access_flags.set_has_miranda_methods(); } 564 565 bool is_cloneable() const; 566 void set_is_cloneable(); 567 568 // Biased locking support 569 // Note: the prototype header is always set up to be at least the 570 // prototype markOop. If biased locking is enabled it may further be 571 // biasable and have an epoch. 572 markOop prototype_header() const { return _prototype_header; } 573 // NOTE: once instances of this klass are floating around in the 574 // system, this header must only be updated at a safepoint. 575 // NOTE 2: currently we only ever set the prototype header to the 576 // biasable prototype for instanceKlasses. There is no technical 577 // reason why it could not be done for arrayKlasses aside from 578 // wanting to reduce the initial scope of this optimization. There 579 // are potential problems in setting the bias pattern for 580 // JVM-internal oops. 581 inline void set_prototype_header(markOop header); 582 static ByteSize prototype_header_offset() { return in_ByteSize(offset_of(Klass, _prototype_header)); } 583 584 int biased_lock_revocation_count() const { return (int) _biased_lock_revocation_count; } 585 // Atomically increments biased_lock_revocation_count and returns updated value 586 int atomic_incr_biased_lock_revocation_count(); 587 void set_biased_lock_revocation_count(int val) { _biased_lock_revocation_count = (jint) val; } 588 jlong last_biased_lock_bulk_revocation_time() { return _last_biased_lock_bulk_revocation_time; } 589 void set_last_biased_lock_bulk_revocation_time(jlong cur_time) { _last_biased_lock_bulk_revocation_time = cur_time; } 590 591 TRACE_DEFINE_TRACE_ID_METHODS; 592 593 // garbage collection support 594 void oops_do(OopClosure* cl); 595 596 // Iff the class loader (or mirror for anonymous classes) is alive the 597 // Klass is considered alive. 598 // The is_alive closure passed in depends on the Garbage Collector used. 599 bool is_loader_alive(BoolObjectClosure* is_alive); 600 601 static void clean_weak_klass_links(BoolObjectClosure* is_alive, bool clean_alive_klasses = true); 602 static void clean_subklass_tree(BoolObjectClosure* is_alive) { 603 clean_weak_klass_links(is_alive, false /* clean_alive_klasses */); 604 } 605 606 // GC specific object visitors 607 // 608 // Mark Sweep 609 virtual int oop_ms_adjust_pointers(oop obj) = 0; 610 #if INCLUDE_ALL_GCS 611 // Parallel Scavenge 612 virtual void oop_ps_push_contents( oop obj, PSPromotionManager* pm) = 0; 613 // Parallel Compact 614 virtual void oop_pc_follow_contents(oop obj, ParCompactionManager* cm) = 0; 615 virtual void oop_pc_update_pointers(oop obj, ParCompactionManager* cm) = 0; 616 #endif 617 618 // Iterators specialized to particular subtypes 619 // of ExtendedOopClosure, to avoid closure virtual calls. 620 #define Klass_OOP_OOP_ITERATE_DECL(OopClosureType, nv_suffix) \ 621 virtual void oop_oop_iterate##nv_suffix(oop obj, OopClosureType* closure) = 0; \ 622 /* Iterates "closure" over all the oops in "obj" (of type "this") within "mr". */ \ 623 virtual void oop_oop_iterate_bounded##nv_suffix(oop obj, OopClosureType* closure, MemRegion mr) = 0; 624 625 ALL_OOP_OOP_ITERATE_CLOSURES_1(Klass_OOP_OOP_ITERATE_DECL) 626 ALL_OOP_OOP_ITERATE_CLOSURES_2(Klass_OOP_OOP_ITERATE_DECL) 627 628 #if INCLUDE_ALL_GCS 629 #define Klass_OOP_OOP_ITERATE_DECL_BACKWARDS(OopClosureType, nv_suffix) \ 630 virtual void oop_oop_iterate_backwards##nv_suffix(oop obj, OopClosureType* closure) = 0; 631 632 ALL_OOP_OOP_ITERATE_CLOSURES_1(Klass_OOP_OOP_ITERATE_DECL_BACKWARDS) 633 ALL_OOP_OOP_ITERATE_CLOSURES_2(Klass_OOP_OOP_ITERATE_DECL_BACKWARDS) 634 #endif // INCLUDE_ALL_GCS 635 636 virtual void array_klasses_do(void f(Klass* k)) {} 637 638 // Return self, except for abstract classes with exactly 1 639 // implementor. Then return the 1 concrete implementation. 640 Klass *up_cast_abstract(); 641 642 // klass name 643 Symbol* name() const { return _name; } 644 void set_name(Symbol* n); 645 646 public: 647 // jvm support 648 virtual jint compute_modifier_flags(TRAPS) const; 649 650 // JVMTI support 651 virtual jint jvmti_class_status() const; 652 653 // Printing 654 virtual void print_on(outputStream* st) const; 655 656 virtual void oop_print_value_on(oop obj, outputStream* st); 657 virtual void oop_print_on (oop obj, outputStream* st); 658 659 virtual const char* internal_name() const = 0; 660 661 // Verification 662 virtual void verify_on(outputStream* st); 663 void verify() { verify_on(tty); } 664 665 #ifndef PRODUCT 666 bool verify_vtable_index(int index); 667 bool verify_itable_index(int index); 668 #endif 669 670 virtual void oop_verify_on(oop obj, outputStream* st); 671 672 static bool is_null(narrowKlass obj); 673 static bool is_null(Klass* obj); 674 675 // klass encoding for klass pointer in objects. 676 static narrowKlass encode_klass_not_null(Klass* v); 677 static narrowKlass encode_klass(Klass* v); 678 679 static Klass* decode_klass_not_null(narrowKlass v); 680 static Klass* decode_klass(narrowKlass v); 681 }; 682 683 // Helper to convert the oop iterate macro suffixes into bool values that can be used by template functions. 684 #define nvs_nv_to_bool true 685 #define nvs_v_to_bool false 686 #define nvs_to_bool(nv_suffix) nvs##nv_suffix##_to_bool 687 688 // Oop iteration macros for declarations. 689 // Used to generate declarations in the *Klass header files. 690 691 #define OOP_OOP_ITERATE_DECL(OopClosureType, nv_suffix) \ 692 void oop_oop_iterate##nv_suffix(oop obj, OopClosureType* closure); \ 693 void oop_oop_iterate_bounded##nv_suffix(oop obj, OopClosureType* closure, MemRegion mr); 694 695 #if INCLUDE_ALL_GCS 696 #define OOP_OOP_ITERATE_DECL_BACKWARDS(OopClosureType, nv_suffix) \ 697 void oop_oop_iterate_backwards##nv_suffix(oop obj, OopClosureType* closure); 698 #endif // INCLUDE_ALL_GCS 699 700 701 // Oop iteration macros for definitions. 702 // Used to generate definitions in the *Klass.inline.hpp files. 703 704 #define OOP_OOP_ITERATE_DEFN(KlassType, OopClosureType, nv_suffix) \ 705 void KlassType::oop_oop_iterate##nv_suffix(oop obj, OopClosureType* closure) { \ 706 oop_oop_iterate<nvs_to_bool(nv_suffix)>(obj, closure); \ 707 } 708 709 #if INCLUDE_ALL_GCS 710 #define OOP_OOP_ITERATE_DEFN_BACKWARDS(KlassType, OopClosureType, nv_suffix) \ 711 void KlassType::oop_oop_iterate_backwards##nv_suffix(oop obj, OopClosureType* closure) { \ 712 oop_oop_iterate_reverse<nvs_to_bool(nv_suffix)>(obj, closure); \ 713 } 714 #else 715 #define OOP_OOP_ITERATE_DEFN_BACKWARDS(KlassType, OopClosureType, nv_suffix) 716 #endif 717 718 #define OOP_OOP_ITERATE_DEFN_BOUNDED(KlassType, OopClosureType, nv_suffix) \ 719 void KlassType::oop_oop_iterate_bounded##nv_suffix(oop obj, OopClosureType* closure, MemRegion mr) { \ 720 oop_oop_iterate_bounded<nvs_to_bool(nv_suffix)>(obj, closure, mr); \ 721 } 722 723 #endif // SHARE_VM_OOPS_KLASS_HPP