1 /* 2 * Copyright (c) 1997, 2014, 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 "runtime/orderAccess.hpp" 36 #include "trace/traceMacros.hpp" 37 #include "utilities/accessFlags.hpp" 38 #include "utilities/macros.hpp" 39 #if INCLUDE_ALL_GCS 40 #include "gc_implementation/concurrentMarkSweep/cmsOopClosures.hpp" 41 #include "gc_implementation/g1/g1OopClosures.hpp" 42 #include "gc_implementation/parNew/parOopClosures.hpp" 43 #endif // INCLUDE_ALL_GCS 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 // Forward declarations. 60 template <class T> class Array; 61 template <class T> class GrowableArray; 62 class ClassLoaderData; 63 class klassVtable; 64 class ParCompactionManager; 65 class KlassSizeStats; 66 67 class Klass : public Metadata { 68 friend class VMStructs; 69 protected: 70 // note: put frequently-used fields together at start of klass structure 71 // for better cache behavior (may not make much of a difference but sure won't hurt) 72 enum { _primary_super_limit = 8 }; 73 74 // The "layout helper" is a combined descriptor of object layout. 75 // For klasses which are neither instance nor array, the value is zero. 76 // 77 // For instances, layout helper is a positive number, the instance size. 78 // This size is already passed through align_object_size and scaled to bytes. 79 // The low order bit is set if instances of this class cannot be 80 // allocated using the fastpath. 81 // 82 // For arrays, layout helper is a negative number, containing four 83 // distinct bytes, as follows: 84 // MSB:[tag, hsz, ebt, log2(esz)]:LSB 85 // where: 86 // tag is 0x80 if the elements are oops, 0xC0 if non-oops 87 // hsz is array header size in bytes (i.e., offset of first element) 88 // ebt is the BasicType of the elements 89 // esz is the element size in bytes 90 // This packed word is arranged so as to be quickly unpacked by the 91 // various fast paths that use the various subfields. 92 // 93 // The esz bits can be used directly by a SLL instruction, without masking. 94 // 95 // Note that the array-kind tag looks like 0x00 for instance klasses, 96 // since their length in bytes is always less than 24Mb. 97 // 98 // Final note: This comes first, immediately after C++ vtable, 99 // because it is frequently queried. 100 jint _layout_helper; 101 102 // The fields _super_check_offset, _secondary_super_cache, _secondary_supers 103 // and _primary_supers all help make fast subtype checks. See big discussion 104 // in doc/server_compiler/checktype.txt 105 // 106 // Where to look to observe a supertype (it is &_secondary_super_cache for 107 // secondary supers, else is &_primary_supers[depth()]. 108 juint _super_check_offset; 109 110 // Class name. Instance classes: java/lang/String, etc. Array classes: [I, 111 // [Ljava/lang/String;, etc. Set to zero for all other kinds of classes. 112 Symbol* _name; 113 114 // Cache of last observed secondary supertype 115 Klass* _secondary_super_cache; 116 // Array of all secondary supertypes 117 Array<Klass*>* _secondary_supers; 118 // Ordered list of all primary supertypes 119 Klass* _primary_supers[_primary_super_limit]; 120 // java/lang/Class instance mirroring this class 121 oop _java_mirror; 122 // Superclass 123 Klass* _super; 124 // First subclass (NULL if none); _subklass->next_sibling() is next one 125 Klass* _subklass; 126 // Sibling link (or NULL); links all subklasses of a klass 127 Klass* _next_sibling; 128 129 // All klasses loaded by a class loader are chained through these links 130 Klass* _next_link; 131 132 // The VM's representation of the ClassLoader used to load this class. 133 // Provide access the corresponding instance java.lang.ClassLoader. 134 ClassLoaderData* _class_loader_data; 135 136 jint _modifier_flags; // Processed access flags, for use by Class.getModifiers. 137 AccessFlags _access_flags; // Access flags. The class/interface distinction is stored here. 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 TRACE_DEFINE_KLASS_TRACE_ID; 146 147 // Remembered sets support for the oops in the klasses. 148 jbyte _modified_oops; // Card Table Equivalent (YC/CMS support) 149 jbyte _accumulated_modified_oops; // Mod Union Equivalent (CMS support) 150 151 // Constructor 152 Klass(); 153 154 void* operator new(size_t size, ClassLoaderData* loader_data, size_t word_size, TRAPS) throw(); 155 156 public: 157 bool is_klass() const volatile { return true; } 158 159 // super 160 Klass* super() const { return _super; } 161 void set_super(Klass* k) { _super = k; } 162 163 // initializes _super link, _primary_supers & _secondary_supers arrays 164 void initialize_supers(Klass* k, TRAPS); 165 void initialize_supers_impl1(Klass* k); 166 void initialize_supers_impl2(Klass* k); 167 168 // klass-specific helper for initializing _secondary_supers 169 virtual GrowableArray<Klass*>* compute_secondary_supers(int num_extra_slots); 170 171 // java_super is the Java-level super type as specified by Class.getSuperClass. 172 virtual Klass* java_super() const { return NULL; } 173 174 juint super_check_offset() const { return _super_check_offset; } 175 void set_super_check_offset(juint o) { _super_check_offset = o; } 176 177 Klass* secondary_super_cache() const { return _secondary_super_cache; } 178 void set_secondary_super_cache(Klass* k) { _secondary_super_cache = k; } 179 180 Array<Klass*>* secondary_supers() const { return _secondary_supers; } 181 void set_secondary_supers(Array<Klass*>* k) { _secondary_supers = k; } 182 183 // Return the element of the _super chain of the given depth. 184 // If there is no such element, return either NULL or this. 185 Klass* primary_super_of_depth(juint i) const { 186 assert(i < primary_super_limit(), "oob"); 187 Klass* super = _primary_supers[i]; 188 assert(super == NULL || super->super_depth() == i, "correct display"); 189 return super; 190 } 191 192 // Can this klass be a primary super? False for interfaces and arrays of 193 // interfaces. False also for arrays or classes with long super chains. 194 bool can_be_primary_super() const { 195 const juint secondary_offset = in_bytes(secondary_super_cache_offset()); 196 return super_check_offset() != secondary_offset; 197 } 198 virtual bool can_be_primary_super_slow() const; 199 200 // Returns number of primary supers; may be a number in the inclusive range [0, primary_super_limit]. 201 juint super_depth() const { 202 if (!can_be_primary_super()) { 203 return primary_super_limit(); 204 } else { 205 juint d = (super_check_offset() - in_bytes(primary_supers_offset())) / sizeof(Klass*); 206 assert(d < primary_super_limit(), "oob"); 207 assert(_primary_supers[d] == this, "proper init"); 208 return d; 209 } 210 } 211 212 // store an oop into a field of a Klass 213 void klass_oop_store(oop* p, oop v); 214 void klass_oop_store(volatile oop* p, oop v); 215 216 // java mirror 217 oop java_mirror() const { return _java_mirror; } 218 void set_java_mirror(oop m) { klass_oop_store(&_java_mirror, m); } 219 220 // modifier flags 221 jint modifier_flags() const { return _modifier_flags; } 222 void set_modifier_flags(jint flags) { _modifier_flags = flags; } 223 224 // size helper 225 int layout_helper() const { return _layout_helper; } 226 void set_layout_helper(int lh) { _layout_helper = lh; } 227 228 // Note: for instances layout_helper() may include padding. 229 // Use InstanceKlass::contains_field_offset to classify field offsets. 230 231 // sub/superklass links 232 Klass* subklass() const { return _subklass; } 233 Klass* next_sibling() const { return _next_sibling; } 234 InstanceKlass* superklass() const; 235 void append_to_sibling_list(); // add newly created receiver to superklass' subklass list 236 237 void set_next_link(Klass* k) { _next_link = k; } 238 Klass* next_link() const { return _next_link; } // The next klass defined by the class loader. 239 240 // class loader data 241 ClassLoaderData* class_loader_data() const { return _class_loader_data; } 242 void set_class_loader_data(ClassLoaderData* loader_data) { _class_loader_data = loader_data; } 243 244 // The Klasses are not placed in the Heap, so the Card Table or 245 // the Mod Union Table can't be used to mark when klasses have modified oops. 246 // The CT and MUT bits saves this information for the individual Klasses. 247 void record_modified_oops() { _modified_oops = 1; } 248 void clear_modified_oops() { _modified_oops = 0; } 249 bool has_modified_oops() { return _modified_oops == 1; } 250 251 void accumulate_modified_oops() { if (has_modified_oops()) _accumulated_modified_oops = 1; } 252 void clear_accumulated_modified_oops() { _accumulated_modified_oops = 0; } 253 bool has_accumulated_modified_oops() { return _accumulated_modified_oops == 1; } 254 255 protected: // internal accessors 256 void set_subklass(Klass* s); 257 void set_next_sibling(Klass* s); 258 259 public: 260 261 // Compiler support 262 static ByteSize super_offset() { return in_ByteSize(offset_of(Klass, _super)); } 263 static ByteSize super_check_offset_offset() { return in_ByteSize(offset_of(Klass, _super_check_offset)); } 264 static ByteSize primary_supers_offset() { return in_ByteSize(offset_of(Klass, _primary_supers)); } 265 static ByteSize secondary_super_cache_offset() { return in_ByteSize(offset_of(Klass, _secondary_super_cache)); } 266 static ByteSize secondary_supers_offset() { return in_ByteSize(offset_of(Klass, _secondary_supers)); } 267 static ByteSize java_mirror_offset() { return in_ByteSize(offset_of(Klass, _java_mirror)); } 268 static ByteSize modifier_flags_offset() { return in_ByteSize(offset_of(Klass, _modifier_flags)); } 269 static ByteSize layout_helper_offset() { return in_ByteSize(offset_of(Klass, _layout_helper)); } 270 static ByteSize access_flags_offset() { return in_ByteSize(offset_of(Klass, _access_flags)); } 271 272 // Unpacking layout_helper: 273 enum { 274 _lh_neutral_value = 0, // neutral non-array non-instance value 275 _lh_instance_slow_path_bit = 0x01, 276 _lh_log2_element_size_shift = BitsPerByte*0, 277 _lh_log2_element_size_mask = BitsPerLong-1, 278 _lh_element_type_shift = BitsPerByte*1, 279 _lh_element_type_mask = right_n_bits(BitsPerByte), // shifted mask 280 _lh_header_size_shift = BitsPerByte*2, 281 _lh_header_size_mask = right_n_bits(BitsPerByte), // shifted mask 282 _lh_array_tag_bits = 2, 283 _lh_array_tag_shift = BitsPerInt - _lh_array_tag_bits, 284 _lh_array_tag_type_value = ~0x00, // 0xC0000000 >> 30 285 _lh_array_tag_obj_value = ~0x01 // 0x80000000 >> 30 286 }; 287 288 static int layout_helper_size_in_bytes(jint lh) { 289 assert(lh > (jint)_lh_neutral_value, "must be instance"); 290 return (int) lh & ~_lh_instance_slow_path_bit; 291 } 292 static bool layout_helper_needs_slow_path(jint lh) { 293 assert(lh > (jint)_lh_neutral_value, "must be instance"); 294 return (lh & _lh_instance_slow_path_bit) != 0; 295 } 296 static bool layout_helper_is_instance(jint lh) { 297 return (jint)lh > (jint)_lh_neutral_value; 298 } 299 static bool layout_helper_is_array(jint lh) { 300 return (jint)lh < (jint)_lh_neutral_value; 301 } 302 static bool layout_helper_is_typeArray(jint lh) { 303 // _lh_array_tag_type_value == (lh >> _lh_array_tag_shift); 304 return (juint)lh >= (juint)(_lh_array_tag_type_value << _lh_array_tag_shift); 305 } 306 static bool layout_helper_is_objArray(jint lh) { 307 // _lh_array_tag_obj_value == (lh >> _lh_array_tag_shift); 308 return (jint)lh < (jint)(_lh_array_tag_type_value << _lh_array_tag_shift); 309 } 310 static int layout_helper_header_size(jint lh) { 311 assert(lh < (jint)_lh_neutral_value, "must be array"); 312 int hsize = (lh >> _lh_header_size_shift) & _lh_header_size_mask; 313 assert(hsize > 0 && hsize < (int)sizeof(oopDesc)*3, "sanity"); 314 return hsize; 315 } 316 static BasicType layout_helper_element_type(jint lh) { 317 assert(lh < (jint)_lh_neutral_value, "must be array"); 318 int btvalue = (lh >> _lh_element_type_shift) & _lh_element_type_mask; 319 assert(btvalue >= T_BOOLEAN && btvalue <= T_OBJECT, "sanity"); 320 return (BasicType) btvalue; 321 } 322 static int layout_helper_log2_element_size(jint lh) { 323 assert(lh < (jint)_lh_neutral_value, "must be array"); 324 int l2esz = (lh >> _lh_log2_element_size_shift) & _lh_log2_element_size_mask; 325 assert(l2esz <= LogBitsPerLong, 326 err_msg("sanity. l2esz: 0x%x for lh: 0x%x", (uint)l2esz, (uint)lh)); 327 return l2esz; 328 } 329 static jint array_layout_helper(jint tag, int hsize, BasicType etype, int log2_esize) { 330 return (tag << _lh_array_tag_shift) 331 | (hsize << _lh_header_size_shift) 332 | ((int)etype << _lh_element_type_shift) 333 | (log2_esize << _lh_log2_element_size_shift); 334 } 335 static jint instance_layout_helper(jint size, bool slow_path_flag) { 336 return (size << LogHeapWordSize) 337 | (slow_path_flag ? _lh_instance_slow_path_bit : 0); 338 } 339 static int layout_helper_to_size_helper(jint lh) { 340 assert(lh > (jint)_lh_neutral_value, "must be instance"); 341 // Note that the following expression discards _lh_instance_slow_path_bit. 342 return lh >> LogHeapWordSize; 343 } 344 // Out-of-line version computes everything based on the etype: 345 static jint array_layout_helper(BasicType etype); 346 347 // What is the maximum number of primary superclasses any klass can have? 348 #ifdef PRODUCT 349 static juint primary_super_limit() { return _primary_super_limit; } 350 #else 351 static juint primary_super_limit() { 352 assert(FastSuperclassLimit <= _primary_super_limit, "parameter oob"); 353 return FastSuperclassLimit; 354 } 355 #endif 356 357 // vtables 358 virtual klassVtable* vtable() const { return NULL; } 359 virtual int vtable_length() const { return 0; } 360 361 // subclass check 362 bool is_subclass_of(const Klass* k) const; 363 // subtype check: true if is_subclass_of, or if k is interface and receiver implements it 364 bool is_subtype_of(Klass* k) const { 365 juint off = k->super_check_offset(); 366 Klass* sup = *(Klass**)( (address)this + off ); 367 const juint secondary_offset = in_bytes(secondary_super_cache_offset()); 368 if (sup == k) { 369 return true; 370 } else if (off != secondary_offset) { 371 return false; 372 } else { 373 return search_secondary_supers(k); 374 } 375 } 376 bool search_secondary_supers(Klass* k) const; 377 378 // Find LCA in class hierarchy 379 Klass *LCA( Klass *k ); 380 381 // Check whether reflection/jni/jvm code is allowed to instantiate this class; 382 // if not, throw either an Error or an Exception. 383 virtual void check_valid_for_instantiation(bool throwError, TRAPS); 384 385 // array copying 386 virtual void copy_array(arrayOop s, int src_pos, arrayOop d, int dst_pos, int length, TRAPS); 387 388 // tells if the class should be initialized 389 virtual bool should_be_initialized() const { return false; } 390 // initializes the klass 391 virtual void initialize(TRAPS); 392 // lookup operation for MethodLookupCache 393 friend class MethodLookupCache; 394 virtual Method* uncached_lookup_method(Symbol* name, Symbol* signature, bool ignore_overpass) const; 395 public: 396 Method* lookup_method(Symbol* name, Symbol* signature) const { 397 return uncached_lookup_method(name, signature, false); 398 } 399 400 // array class with specific rank 401 Klass* array_klass(int rank, TRAPS) { return array_klass_impl(false, rank, THREAD); } 402 403 // array class with this klass as element type 404 Klass* array_klass(TRAPS) { return array_klass_impl(false, THREAD); } 405 406 // These will return NULL instead of allocating on the heap: 407 // NB: these can block for a mutex, like other functions with TRAPS arg. 408 Klass* array_klass_or_null(int rank); 409 Klass* array_klass_or_null(); 410 411 virtual oop protection_domain() const = 0; 412 413 oop class_loader() const; 414 415 virtual oop klass_holder() const { return class_loader(); } 416 417 protected: 418 virtual Klass* array_klass_impl(bool or_null, int rank, TRAPS); 419 virtual Klass* array_klass_impl(bool or_null, TRAPS); 420 421 public: 422 // CDS support - remove and restore oops from metadata. Oops are not shared. 423 virtual void remove_unshareable_info(); 424 virtual void restore_unshareable_info(TRAPS); 425 426 protected: 427 // computes the subtype relationship 428 virtual bool compute_is_subtype_of(Klass* k); 429 public: 430 // subclass accessor (here for convenience; undefined for non-klass objects) 431 virtual bool is_leaf_class() const { fatal("not a class"); return false; } 432 public: 433 // ALL FUNCTIONS BELOW THIS POINT ARE DISPATCHED FROM AN OOP 434 // These functions describe behavior for the oop not the KLASS. 435 436 // actual oop size of obj in memory 437 virtual int oop_size(oop obj) const = 0; 438 439 // Size of klass in word size. 440 virtual int size() const = 0; 441 #if INCLUDE_SERVICES 442 virtual void collect_statistics(KlassSizeStats *sz) const; 443 #endif 444 445 // Returns the Java name for a class (Resource allocated) 446 // For arrays, this returns the name of the element with a leading '['. 447 // For classes, this returns the name with the package separators 448 // turned into '.'s. 449 const char* external_name() const; 450 // Returns the name for a class (Resource allocated) as the class 451 // would appear in a signature. 452 // For arrays, this returns the name of the element with a leading '['. 453 // For classes, this returns the name with a leading 'L' and a trailing ';' 454 // and the package separators as '/'. 455 virtual const char* signature_name() const; 456 457 // garbage collection support 458 virtual void oop_follow_contents(oop obj) = 0; 459 virtual int oop_adjust_pointers(oop obj) = 0; 460 461 // Parallel Scavenge and Parallel Old 462 PARALLEL_GC_DECLS_PV 463 464 // type testing operations 465 protected: 466 virtual bool oop_is_instance_slow() const { return false; } 467 virtual bool oop_is_array_slow() const { return false; } 468 virtual bool oop_is_objArray_slow() const { return false; } 469 virtual bool oop_is_typeArray_slow() const { return false; } 470 public: 471 virtual bool oop_is_instanceClassLoader() const { return false; } 472 virtual bool oop_is_instanceMirror() const { return false; } 473 virtual bool oop_is_instanceRef() const { return false; } 474 475 // Fast non-virtual versions 476 #ifndef ASSERT 477 #define assert_same_query(xval, xcheck) xval 478 #else 479 private: 480 static bool assert_same_query(bool xval, bool xslow) { 481 assert(xval == xslow, "slow and fast queries agree"); 482 return xval; 483 } 484 public: 485 #endif 486 inline bool oop_is_instance() const { return assert_same_query( 487 layout_helper_is_instance(layout_helper()), 488 oop_is_instance_slow()); } 489 inline bool oop_is_array() const { return assert_same_query( 490 layout_helper_is_array(layout_helper()), 491 oop_is_array_slow()); } 492 inline bool oop_is_objArray() const { return assert_same_query( 493 layout_helper_is_objArray(layout_helper()), 494 oop_is_objArray_slow()); } 495 inline bool oop_is_typeArray() const { return assert_same_query( 496 layout_helper_is_typeArray(layout_helper()), 497 oop_is_typeArray_slow()); } 498 #undef assert_same_query 499 500 // Access flags 501 AccessFlags access_flags() const { return _access_flags; } 502 void set_access_flags(AccessFlags flags) { _access_flags = flags; } 503 504 bool is_public() const { return _access_flags.is_public(); } 505 bool is_final() const { return _access_flags.is_final(); } 506 bool is_interface() const { return _access_flags.is_interface(); } 507 bool is_abstract() const { return _access_flags.is_abstract(); } 508 bool is_super() const { return _access_flags.is_super(); } 509 bool is_synthetic() const { return _access_flags.is_synthetic(); } 510 void set_is_synthetic() { _access_flags.set_is_synthetic(); } 511 bool has_finalizer() const { return _access_flags.has_finalizer(); } 512 bool has_final_method() const { return _access_flags.has_final_method(); } 513 void set_has_finalizer() { _access_flags.set_has_finalizer(); } 514 void set_has_final_method() { _access_flags.set_has_final_method(); } 515 bool is_cloneable() const { return _access_flags.is_cloneable(); } 516 void set_is_cloneable() { _access_flags.set_is_cloneable(); } 517 bool has_vanilla_constructor() const { return _access_flags.has_vanilla_constructor(); } 518 void set_has_vanilla_constructor() { _access_flags.set_has_vanilla_constructor(); } 519 bool has_miranda_methods () const { return access_flags().has_miranda_methods(); } 520 void set_has_miranda_methods() { _access_flags.set_has_miranda_methods(); } 521 522 // Biased locking support 523 // Note: the prototype header is always set up to be at least the 524 // prototype markOop. If biased locking is enabled it may further be 525 // biasable and have an epoch. 526 markOop prototype_header() const { return _prototype_header; } 527 // NOTE: once instances of this klass are floating around in the 528 // system, this header must only be updated at a safepoint. 529 // NOTE 2: currently we only ever set the prototype header to the 530 // biasable prototype for instanceKlasses. There is no technical 531 // reason why it could not be done for arrayKlasses aside from 532 // wanting to reduce the initial scope of this optimization. There 533 // are potential problems in setting the bias pattern for 534 // JVM-internal oops. 535 inline void set_prototype_header(markOop header); 536 static ByteSize prototype_header_offset() { return in_ByteSize(offset_of(Klass, _prototype_header)); } 537 538 int biased_lock_revocation_count() const { return (int) _biased_lock_revocation_count; } 539 // Atomically increments biased_lock_revocation_count and returns updated value 540 int atomic_incr_biased_lock_revocation_count(); 541 void set_biased_lock_revocation_count(int val) { _biased_lock_revocation_count = (jint) val; } 542 jlong last_biased_lock_bulk_revocation_time() { return _last_biased_lock_bulk_revocation_time; } 543 void set_last_biased_lock_bulk_revocation_time(jlong cur_time) { _last_biased_lock_bulk_revocation_time = cur_time; } 544 545 TRACE_DEFINE_KLASS_METHODS; 546 547 // garbage collection support 548 virtual void oops_do(OopClosure* cl); 549 550 // Iff the class loader (or mirror for anonymous classes) is alive the 551 // Klass is considered alive. 552 // The is_alive closure passed in depends on the Garbage Collector used. 553 bool is_loader_alive(BoolObjectClosure* is_alive); 554 555 static void clean_weak_klass_links(BoolObjectClosure* is_alive); 556 557 // Prefetch within oop iterators. This is a macro because we 558 // can't guarantee that the compiler will inline it. In 64-bit 559 // it generally doesn't. Signature is 560 // 561 // static void prefetch_beyond(oop* const start, 562 // oop* const end, 563 // const intx foffset, 564 // const Prefetch::style pstyle); 565 #define prefetch_beyond(start, end, foffset, pstyle) { \ 566 const intx foffset_ = (foffset); \ 567 const Prefetch::style pstyle_ = (pstyle); \ 568 assert(foffset_ > 0, "prefetch beyond, not behind"); \ 569 if (pstyle_ != Prefetch::do_none) { \ 570 oop* ref = (start); \ 571 if (ref < (end)) { \ 572 switch (pstyle_) { \ 573 case Prefetch::do_read: \ 574 Prefetch::read(*ref, foffset_); \ 575 break; \ 576 case Prefetch::do_write: \ 577 Prefetch::write(*ref, foffset_); \ 578 break; \ 579 default: \ 580 ShouldNotReachHere(); \ 581 break; \ 582 } \ 583 } \ 584 } \ 585 } 586 587 // iterators 588 virtual int oop_oop_iterate(oop obj, ExtendedOopClosure* blk) = 0; 589 virtual int oop_oop_iterate_v(oop obj, ExtendedOopClosure* blk) { 590 return oop_oop_iterate(obj, blk); 591 } 592 593 #if INCLUDE_ALL_GCS 594 // In case we don't have a specialized backward scanner use forward 595 // iteration. 596 virtual int oop_oop_iterate_backwards_v(oop obj, ExtendedOopClosure* blk) { 597 return oop_oop_iterate_v(obj, blk); 598 } 599 #endif // INCLUDE_ALL_GCS 600 601 // Iterates "blk" over all the oops in "obj" (of type "this") within "mr". 602 // (I don't see why the _m should be required, but without it the Solaris 603 // C++ gives warning messages about overridings of the "oop_oop_iterate" 604 // defined above "hiding" this virtual function. (DLD, 6/20/00)) */ 605 virtual int oop_oop_iterate_m(oop obj, ExtendedOopClosure* blk, MemRegion mr) = 0; 606 virtual int oop_oop_iterate_v_m(oop obj, ExtendedOopClosure* blk, MemRegion mr) { 607 return oop_oop_iterate_m(obj, blk, mr); 608 } 609 610 // Versions of the above iterators specialized to particular subtypes 611 // of OopClosure, to avoid closure virtual calls. 612 #define Klass_OOP_OOP_ITERATE_DECL(OopClosureType, nv_suffix) \ 613 virtual int oop_oop_iterate##nv_suffix(oop obj, OopClosureType* blk) { \ 614 /* Default implementation reverts to general version. */ \ 615 return oop_oop_iterate(obj, blk); \ 616 } \ 617 \ 618 /* Iterates "blk" over all the oops in "obj" (of type "this") within "mr". \ 619 (I don't see why the _m should be required, but without it the Solaris \ 620 C++ gives warning messages about overridings of the "oop_oop_iterate" \ 621 defined above "hiding" this virtual function. (DLD, 6/20/00)) */ \ 622 virtual int oop_oop_iterate##nv_suffix##_m(oop obj, \ 623 OopClosureType* blk, \ 624 MemRegion mr) { \ 625 return oop_oop_iterate_m(obj, blk, mr); \ 626 } 627 628 SPECIALIZED_OOP_OOP_ITERATE_CLOSURES_1(Klass_OOP_OOP_ITERATE_DECL) 629 SPECIALIZED_OOP_OOP_ITERATE_CLOSURES_2(Klass_OOP_OOP_ITERATE_DECL) 630 631 #if INCLUDE_ALL_GCS 632 #define Klass_OOP_OOP_ITERATE_BACKWARDS_DECL(OopClosureType, nv_suffix) \ 633 virtual int oop_oop_iterate_backwards##nv_suffix(oop obj, \ 634 OopClosureType* blk) { \ 635 /* Default implementation reverts to general version. */ \ 636 return oop_oop_iterate_backwards_v(obj, blk); \ 637 } 638 639 SPECIALIZED_OOP_OOP_ITERATE_CLOSURES_1(Klass_OOP_OOP_ITERATE_BACKWARDS_DECL) 640 SPECIALIZED_OOP_OOP_ITERATE_CLOSURES_2(Klass_OOP_OOP_ITERATE_BACKWARDS_DECL) 641 #endif // INCLUDE_ALL_GCS 642 643 virtual void array_klasses_do(void f(Klass* k)) {} 644 645 // Return self, except for abstract classes with exactly 1 646 // implementor. Then return the 1 concrete implementation. 647 Klass *up_cast_abstract(); 648 649 // klass name 650 Symbol* name() const { return _name; } 651 void set_name(Symbol* n); 652 653 public: 654 // jvm support 655 virtual jint compute_modifier_flags(TRAPS) const; 656 657 // JVMTI support 658 virtual jint jvmti_class_status() const; 659 660 // Printing 661 virtual void print_on(outputStream* st) const; 662 663 virtual void oop_print_value_on(oop obj, outputStream* st); 664 virtual void oop_print_on (oop obj, outputStream* st); 665 666 virtual const char* internal_name() const = 0; 667 668 // Verification 669 virtual void verify_on(outputStream* st); 670 void verify() { verify_on(tty); } 671 672 #ifndef PRODUCT 673 bool verify_vtable_index(int index); 674 bool verify_itable_index(int index); 675 #endif 676 677 virtual void oop_verify_on(oop obj, outputStream* st); 678 679 static bool is_null(narrowKlass obj); 680 static bool is_null(Klass* obj); 681 682 // klass encoding for klass pointer in objects. 683 static narrowKlass encode_klass_not_null(Klass* v); 684 static narrowKlass encode_klass(Klass* v); 685 686 static Klass* decode_klass_not_null(narrowKlass v); 687 static Klass* decode_klass(narrowKlass v); 688 689 private: 690 // barriers used by klass_oop_store 691 void klass_update_barrier_set(oop v); 692 void klass_update_barrier_set_pre(void* p, oop v); 693 }; 694 695 #endif // SHARE_VM_OOPS_KLASS_HPP