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