1 /* 2 * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #ifndef SHARE_VM_OOPS_KLASS_HPP 26 #define SHARE_VM_OOPS_KLASS_HPP 27 28 #include "classfile/classLoaderData.hpp" 29 #include "memory/iterator.hpp" 30 #include "memory/memRegion.hpp" 31 #include "oops/metadata.hpp" 32 #include "oops/oop.hpp" 33 #include "oops/oopHandle.hpp" 34 #include "utilities/accessFlags.hpp" 35 #include "utilities/macros.hpp" 36 #if INCLUDE_JFR 37 #include "jfr/support/jfrTraceIdExtension.hpp" 38 #endif 39 40 // Klass IDs for all subclasses of Klass 41 enum KlassID { 42 InstanceKlassID, 43 InstanceRefKlassID, 44 InstanceMirrorKlassID, 45 InstanceClassLoaderKlassID, 46 TypeArrayKlassID, 47 ObjArrayKlassID 48 }; 49 50 const uint KLASS_ID_COUNT = 6; 51 52 // 53 // A Klass provides: 54 // 1: language level class object (method dictionary etc.) 55 // 2: provide vm dispatch behavior for the object 56 // Both functions are combined into one C++ class. 57 58 // One reason for the oop/klass dichotomy in the implementation is 59 // that we don't want a C++ vtbl pointer in every object. Thus, 60 // normal oops don't have any virtual functions. Instead, they 61 // forward all "virtual" functions to their klass, which does have 62 // a vtbl and does the C++ dispatch depending on the object's 63 // actual type. (See oop.inline.hpp for some of the forwarding code.) 64 // ALL FUNCTIONS IMPLEMENTING THIS DISPATCH ARE PREFIXED WITH "oop_"! 65 66 // Forward declarations. 67 template <class T> class Array; 68 template <class T> class GrowableArray; 69 class fieldDescriptor; 70 class KlassSizeStats; 71 class klassVtable; 72 class ModuleEntry; 73 class PackageEntry; 74 class ParCompactionManager; 75 class PSPromotionManager; 76 class vtableEntry; 77 78 class Klass : public Metadata { 79 friend class VMStructs; 80 friend class JVMCIVMStructs; 81 protected: 82 // If you add a new field that points to any metaspace object, you 83 // must add this field to Klass::metaspace_pointers_do(). 84 85 // note: put frequently-used fields together at start of klass structure 86 // for better cache behavior (may not make much of a difference but sure won't hurt) 87 enum { _primary_super_limit = 8 }; 88 89 // The "layout helper" is a combined descriptor of object layout. 90 // For klasses which are neither instance nor array, the value is zero. 91 // 92 // For instances, layout helper is a positive number, the instance size. 93 // This size is already passed through align_object_size and scaled to bytes. 94 // The low order bit is set if instances of this class cannot be 95 // allocated using the fastpath. 96 // 97 // For arrays, layout helper is a negative number, containing four 98 // distinct bytes, as follows: 99 // MSB:[tag, hsz, ebt, log2(esz)]:LSB 100 // where: 101 // tag is 0x80 if the elements are oops, 0xC0 if non-oops 102 // hsz is array header size in bytes (i.e., offset of first element) 103 // ebt is the BasicType of the elements 104 // esz is the element size in bytes 105 // This packed word is arranged so as to be quickly unpacked by the 106 // various fast paths that use the various subfields. 107 // 108 // The esz bits can be used directly by a SLL instruction, without masking. 109 // 110 // Note that the array-kind tag looks like 0x00 for instance klasses, 111 // since their length in bytes is always less than 24Mb. 112 // 113 // Final note: This comes first, immediately after C++ vtable, 114 // because it is frequently queried. 115 jint _layout_helper; 116 117 // Klass identifier used to implement devirtualized oop closure dispatching. 118 const KlassID _id; 119 120 // The fields _super_check_offset, _secondary_super_cache, _secondary_supers 121 // and _primary_supers all help make fast subtype checks. See big discussion 122 // in doc/server_compiler/checktype.txt 123 // 124 // Where to look to observe a supertype (it is &_secondary_super_cache for 125 // secondary supers, else is &_primary_supers[depth()]. 126 juint _super_check_offset; 127 128 // Class name. Instance classes: java/lang/String, etc. Array classes: [I, 129 // [Ljava/lang/String;, etc. Set to zero for all other kinds of classes. 130 Symbol* _name; 131 132 // Cache of last observed secondary supertype 133 Klass* _secondary_super_cache; 134 // Array of all secondary supertypes 135 Array<Klass*>* _secondary_supers; 136 // Ordered list of all primary supertypes 137 Klass* _primary_supers[_primary_super_limit]; 138 // java/lang/Class instance mirroring this class 139 OopHandle _java_mirror; 140 // Superclass 141 Klass* _super; 142 // First subclass (NULL if none); _subklass->next_sibling() is next one 143 Klass* volatile _subklass; 144 // Sibling link (or NULL); links all subklasses of a klass 145 Klass* volatile _next_sibling; 146 147 // All klasses loaded by a class loader are chained through these links 148 Klass* _next_link; 149 150 // The VM's representation of the ClassLoader used to load this class. 151 // Provide access the corresponding instance java.lang.ClassLoader. 152 ClassLoaderData* _class_loader_data; 153 154 jint _modifier_flags; // Processed access flags, for use by Class.getModifiers. 155 AccessFlags _access_flags; // Access flags. The class/interface distinction is stored here. 156 157 JFR_ONLY(DEFINE_TRACE_ID_FIELD;) 158 159 // Biased locking implementation and statistics 160 // (the 64-bit chunk goes first, to avoid some fragmentation) 161 jlong _last_biased_lock_bulk_revocation_time; 162 markOop _prototype_header; // Used when biased locking is both enabled and disabled for this type 163 jint _biased_lock_revocation_count; 164 165 // vtable length 166 int _vtable_len; 167 168 private: 169 // This is an index into FileMapHeader::_shared_path_table[], to 170 // associate this class with the JAR file where it's loaded from during 171 // dump time. If a class is not loaded from the shared archive, this field is 172 // -1. 173 jshort _shared_class_path_index; 174 175 #if INCLUDE_CDS 176 // Flags of the current shared class. 177 u2 _shared_class_flags; 178 enum { 179 _has_raw_archived_mirror = 1 180 }; 181 #endif 182 // The _archived_mirror is set at CDS dump time pointing to the cached mirror 183 // in the open archive heap region when archiving java object is supported. 184 CDS_JAVA_HEAP_ONLY(narrowOop _archived_mirror;) 185 186 protected: 187 188 // Constructor 189 Klass(KlassID id); Klass()190 Klass() : _id(KlassID(-1)) { assert(DumpSharedSpaces || UseSharedSpaces, "only for cds"); } 191 192 void* operator new(size_t size, ClassLoaderData* loader_data, size_t word_size, TRAPS) throw(); 193 194 public: id()195 int id() { return _id; } 196 197 enum DefaultsLookupMode { find_defaults, skip_defaults }; 198 enum OverpassLookupMode { find_overpass, skip_overpass }; 199 enum StaticLookupMode { find_static, skip_static }; 200 enum PrivateLookupMode { find_private, skip_private }; 201 is_klass() const202 bool is_klass() const volatile { return true; } 203 204 // super() cannot be InstanceKlass* -- Java arrays are covariant, and _super is used 205 // to implement that. NB: the _super of "[Ljava/lang/Integer;" is "[Ljava/lang/Number;" 206 // If this is not what your code expects, you're probably looking for Klass::java_super(). super() const207 Klass* super() const { return _super; } set_super(Klass * k)208 void set_super(Klass* k) { _super = k; } 209 210 // initializes _super link, _primary_supers & _secondary_supers arrays 211 void initialize_supers(Klass* k, Array<InstanceKlass*>* transitive_interfaces, TRAPS); 212 213 // klass-specific helper for initializing _secondary_supers 214 virtual GrowableArray<Klass*>* compute_secondary_supers(int num_extra_slots, 215 Array<InstanceKlass*>* transitive_interfaces); 216 217 // java_super is the Java-level super type as specified by Class.getSuperClass. java_super() const218 virtual InstanceKlass* java_super() const { return NULL; } 219 super_check_offset() const220 juint super_check_offset() const { return _super_check_offset; } set_super_check_offset(juint o)221 void set_super_check_offset(juint o) { _super_check_offset = o; } 222 secondary_super_cache() const223 Klass* secondary_super_cache() const { return _secondary_super_cache; } set_secondary_super_cache(Klass * k)224 void set_secondary_super_cache(Klass* k) { _secondary_super_cache = k; } 225 secondary_supers() const226 Array<Klass*>* secondary_supers() const { return _secondary_supers; } set_secondary_supers(Array<Klass * > * k)227 void set_secondary_supers(Array<Klass*>* k) { _secondary_supers = k; } 228 229 // Return the element of the _super chain of the given depth. 230 // If there is no such element, return either NULL or this. primary_super_of_depth(juint i) const231 Klass* primary_super_of_depth(juint i) const { 232 assert(i < primary_super_limit(), "oob"); 233 Klass* super = _primary_supers[i]; 234 assert(super == NULL || super->super_depth() == i, "correct display"); 235 return super; 236 } 237 238 // Can this klass be a primary super? False for interfaces and arrays of 239 // interfaces. False also for arrays or classes with long super chains. can_be_primary_super() const240 bool can_be_primary_super() const { 241 const juint secondary_offset = in_bytes(secondary_super_cache_offset()); 242 return super_check_offset() != secondary_offset; 243 } 244 virtual bool can_be_primary_super_slow() const; 245 246 // Returns number of primary supers; may be a number in the inclusive range [0, primary_super_limit]. super_depth() const247 juint super_depth() const { 248 if (!can_be_primary_super()) { 249 return primary_super_limit(); 250 } else { 251 juint d = (super_check_offset() - in_bytes(primary_supers_offset())) / sizeof(Klass*); 252 assert(d < primary_super_limit(), "oob"); 253 assert(_primary_supers[d] == this, "proper init"); 254 return d; 255 } 256 } 257 258 // java mirror 259 oop java_mirror() const; 260 oop java_mirror_no_keepalive() const; 261 void set_java_mirror(Handle m); 262 263 oop archived_java_mirror_raw() NOT_CDS_JAVA_HEAP_RETURN_(NULL); // no GC barrier 264 narrowOop archived_java_mirror_raw_narrow() NOT_CDS_JAVA_HEAP_RETURN_(0); // no GC barrier 265 void set_archived_java_mirror_raw(oop m) NOT_CDS_JAVA_HEAP_RETURN; // no GC barrier 266 267 // Temporary mirror switch used by RedefineClasses 268 // Both mirrors are on the ClassLoaderData::_handles list already so no 269 // barriers are needed. set_java_mirror_handle(OopHandle mirror)270 void set_java_mirror_handle(OopHandle mirror) { _java_mirror = mirror; } java_mirror_handle() const271 OopHandle java_mirror_handle() const { 272 return _java_mirror; 273 } 274 275 // modifier flags modifier_flags() const276 jint modifier_flags() const { return _modifier_flags; } set_modifier_flags(jint flags)277 void set_modifier_flags(jint flags) { _modifier_flags = flags; } 278 279 // size helper layout_helper() const280 int layout_helper() const { return _layout_helper; } set_layout_helper(int lh)281 void set_layout_helper(int lh) { _layout_helper = lh; } 282 283 // Note: for instances layout_helper() may include padding. 284 // Use InstanceKlass::contains_field_offset to classify field offsets. 285 286 // sub/superklass links 287 Klass* subklass(bool log = false) const; 288 Klass* next_sibling(bool log = false) const; 289 290 InstanceKlass* superklass() const; 291 void append_to_sibling_list(); // add newly created receiver to superklass' subklass list 292 set_next_link(Klass * k)293 void set_next_link(Klass* k) { _next_link = k; } next_link() const294 Klass* next_link() const { return _next_link; } // The next klass defined by the class loader. 295 296 // class loader data class_loader_data() const297 ClassLoaderData* class_loader_data() const { return _class_loader_data; } set_class_loader_data(ClassLoaderData * loader_data)298 void set_class_loader_data(ClassLoaderData* loader_data) { _class_loader_data = loader_data; } 299 shared_classpath_index() const300 int shared_classpath_index() const { 301 return _shared_class_path_index; 302 }; 303 set_shared_classpath_index(int index)304 void set_shared_classpath_index(int index) { 305 _shared_class_path_index = index; 306 }; 307 set_has_raw_archived_mirror()308 void set_has_raw_archived_mirror() { 309 CDS_ONLY(_shared_class_flags |= _has_raw_archived_mirror;) 310 } clear_has_raw_archived_mirror()311 void clear_has_raw_archived_mirror() { 312 CDS_ONLY(_shared_class_flags &= ~_has_raw_archived_mirror;) 313 } has_raw_archived_mirror() const314 bool has_raw_archived_mirror() const { 315 CDS_ONLY(return (_shared_class_flags & _has_raw_archived_mirror) != 0;) 316 NOT_CDS(return false;) 317 } 318 319 // Obtain the module or package for this class 320 virtual ModuleEntry* module() const = 0; 321 virtual PackageEntry* package() const = 0; 322 323 protected: // internal accessors 324 void set_subklass(Klass* s); 325 void set_next_sibling(Klass* s); 326 327 public: 328 329 // Compiler support super_offset()330 static ByteSize super_offset() { return in_ByteSize(offset_of(Klass, _super)); } super_check_offset_offset()331 static ByteSize super_check_offset_offset() { return in_ByteSize(offset_of(Klass, _super_check_offset)); } primary_supers_offset()332 static ByteSize primary_supers_offset() { return in_ByteSize(offset_of(Klass, _primary_supers)); } secondary_super_cache_offset()333 static ByteSize secondary_super_cache_offset() { return in_ByteSize(offset_of(Klass, _secondary_super_cache)); } secondary_supers_offset()334 static ByteSize secondary_supers_offset() { return in_ByteSize(offset_of(Klass, _secondary_supers)); } java_mirror_offset()335 static ByteSize java_mirror_offset() { return in_ByteSize(offset_of(Klass, _java_mirror)); } modifier_flags_offset()336 static ByteSize modifier_flags_offset() { return in_ByteSize(offset_of(Klass, _modifier_flags)); } layout_helper_offset()337 static ByteSize layout_helper_offset() { return in_ByteSize(offset_of(Klass, _layout_helper)); } access_flags_offset()338 static ByteSize access_flags_offset() { return in_ByteSize(offset_of(Klass, _access_flags)); } 339 340 // Unpacking layout_helper: 341 enum { 342 _lh_neutral_value = 0, // neutral non-array non-instance value 343 _lh_instance_slow_path_bit = 0x01, 344 _lh_log2_element_size_shift = BitsPerByte*0, 345 _lh_log2_element_size_mask = BitsPerLong-1, 346 _lh_element_type_shift = BitsPerByte*1, 347 _lh_element_type_mask = right_n_bits(BitsPerByte), // shifted mask 348 _lh_header_size_shift = BitsPerByte*2, 349 _lh_header_size_mask = right_n_bits(BitsPerByte), // shifted mask 350 _lh_array_tag_bits = 2, 351 _lh_array_tag_shift = BitsPerInt - _lh_array_tag_bits, 352 _lh_array_tag_obj_value = ~0x01 // 0x80000000 >> 30 353 }; 354 355 static const unsigned int _lh_array_tag_type_value = 0Xffffffff; // ~0x00, // 0xC0000000 >> 30 356 layout_helper_size_in_bytes(jint lh)357 static int layout_helper_size_in_bytes(jint lh) { 358 assert(lh > (jint)_lh_neutral_value, "must be instance"); 359 return (int) lh & ~_lh_instance_slow_path_bit; 360 } layout_helper_needs_slow_path(jint lh)361 static bool layout_helper_needs_slow_path(jint lh) { 362 assert(lh > (jint)_lh_neutral_value, "must be instance"); 363 return (lh & _lh_instance_slow_path_bit) != 0; 364 } layout_helper_is_instance(jint lh)365 static bool layout_helper_is_instance(jint lh) { 366 return (jint)lh > (jint)_lh_neutral_value; 367 } layout_helper_is_array(jint lh)368 static bool layout_helper_is_array(jint lh) { 369 return (jint)lh < (jint)_lh_neutral_value; 370 } layout_helper_is_typeArray(jint lh)371 static bool layout_helper_is_typeArray(jint lh) { 372 // _lh_array_tag_type_value == (lh >> _lh_array_tag_shift); 373 return (juint)lh >= (juint)(_lh_array_tag_type_value << _lh_array_tag_shift); 374 } layout_helper_is_objArray(jint lh)375 static bool layout_helper_is_objArray(jint lh) { 376 // _lh_array_tag_obj_value == (lh >> _lh_array_tag_shift); 377 return (jint)lh < (jint)(_lh_array_tag_type_value << _lh_array_tag_shift); 378 } layout_helper_header_size(jint lh)379 static int layout_helper_header_size(jint lh) { 380 assert(lh < (jint)_lh_neutral_value, "must be array"); 381 int hsize = (lh >> _lh_header_size_shift) & _lh_header_size_mask; 382 assert(hsize > 0 && hsize < (int)sizeof(oopDesc)*3, "sanity"); 383 return hsize; 384 } layout_helper_element_type(jint lh)385 static BasicType layout_helper_element_type(jint lh) { 386 assert(lh < (jint)_lh_neutral_value, "must be array"); 387 int btvalue = (lh >> _lh_element_type_shift) & _lh_element_type_mask; 388 assert(btvalue >= T_BOOLEAN && btvalue <= T_OBJECT, "sanity"); 389 return (BasicType) btvalue; 390 } 391 392 // Want a pattern to quickly diff against layout header in register 393 // find something less clever! layout_helper_boolean_diffbit()394 static int layout_helper_boolean_diffbit() { 395 jint zlh = array_layout_helper(T_BOOLEAN); 396 jint blh = array_layout_helper(T_BYTE); 397 assert(zlh != blh, "array layout helpers must differ"); 398 int diffbit = 1; 399 while ((diffbit & (zlh ^ blh)) == 0 && (diffbit & zlh) == 0) { 400 diffbit <<= 1; 401 assert(diffbit != 0, "make sure T_BOOLEAN has a different bit than T_BYTE"); 402 } 403 return diffbit; 404 } 405 layout_helper_log2_element_size(jint lh)406 static int layout_helper_log2_element_size(jint lh) { 407 assert(lh < (jint)_lh_neutral_value, "must be array"); 408 int l2esz = (lh >> _lh_log2_element_size_shift) & _lh_log2_element_size_mask; 409 assert(l2esz <= LogBytesPerLong, 410 "sanity. l2esz: 0x%x for lh: 0x%x", (uint)l2esz, (uint)lh); 411 return l2esz; 412 } array_layout_helper(jint tag,int hsize,BasicType etype,int log2_esize)413 static jint array_layout_helper(jint tag, int hsize, BasicType etype, int log2_esize) { 414 return (tag << _lh_array_tag_shift) 415 | (hsize << _lh_header_size_shift) 416 | ((int)etype << _lh_element_type_shift) 417 | (log2_esize << _lh_log2_element_size_shift); 418 } instance_layout_helper(jint size,bool slow_path_flag)419 static jint instance_layout_helper(jint size, bool slow_path_flag) { 420 return (size << LogBytesPerWord) 421 | (slow_path_flag ? _lh_instance_slow_path_bit : 0); 422 } layout_helper_to_size_helper(jint lh)423 static int layout_helper_to_size_helper(jint lh) { 424 assert(lh > (jint)_lh_neutral_value, "must be instance"); 425 // Note that the following expression discards _lh_instance_slow_path_bit. 426 return lh >> LogBytesPerWord; 427 } 428 // Out-of-line version computes everything based on the etype: 429 static jint array_layout_helper(BasicType etype); 430 431 // What is the maximum number of primary superclasses any klass can have? 432 #ifdef PRODUCT primary_super_limit()433 static juint primary_super_limit() { return _primary_super_limit; } 434 #else primary_super_limit()435 static juint primary_super_limit() { 436 assert(FastSuperclassLimit <= _primary_super_limit, "parameter oob"); 437 return FastSuperclassLimit; 438 } 439 #endif 440 441 // vtables 442 klassVtable vtable() const; vtable_length() const443 int vtable_length() const { return _vtable_len; } 444 445 // subclass check 446 bool is_subclass_of(const Klass* k) const; 447 // subtype check: true if is_subclass_of, or if k is interface and receiver implements it is_subtype_of(Klass * k) const448 bool is_subtype_of(Klass* k) const { 449 juint off = k->super_check_offset(); 450 Klass* sup = *(Klass**)( (address)this + off ); 451 const juint secondary_offset = in_bytes(secondary_super_cache_offset()); 452 if (sup == k) { 453 return true; 454 } else if (off != secondary_offset) { 455 return false; 456 } else { 457 return search_secondary_supers(k); 458 } 459 } 460 461 bool search_secondary_supers(Klass* k) const; 462 463 // Find LCA in class hierarchy 464 Klass *LCA( Klass *k ); 465 466 // Check whether reflection/jni/jvm code is allowed to instantiate this class; 467 // if not, throw either an Error or an Exception. 468 virtual void check_valid_for_instantiation(bool throwError, TRAPS); 469 470 // array copying 471 virtual void copy_array(arrayOop s, int src_pos, arrayOop d, int dst_pos, int length, TRAPS); 472 473 // tells if the class should be initialized should_be_initialized() const474 virtual bool should_be_initialized() const { return false; } 475 // initializes the klass 476 virtual void initialize(TRAPS); 477 // lookup operation for MethodLookupCache 478 friend class MethodLookupCache; 479 virtual Klass* find_field(Symbol* name, Symbol* signature, fieldDescriptor* fd) const; 480 virtual Method* uncached_lookup_method(const Symbol* name, const Symbol* signature, 481 OverpassLookupMode overpass_mode, 482 PrivateLookupMode = find_private) const; 483 public: lookup_method(const Symbol * name,const Symbol * signature) const484 Method* lookup_method(const Symbol* name, const Symbol* signature) const { 485 return uncached_lookup_method(name, signature, find_overpass); 486 } 487 488 // array class with specific rank array_klass(int rank,TRAPS)489 Klass* array_klass(int rank, TRAPS) { return array_klass_impl(false, rank, THREAD); } 490 491 // array class with this klass as element type array_klass(TRAPS)492 Klass* array_klass(TRAPS) { return array_klass_impl(false, THREAD); } 493 494 // These will return NULL instead of allocating on the heap: 495 // NB: these can block for a mutex, like other functions with TRAPS arg. 496 Klass* array_klass_or_null(int rank); 497 Klass* array_klass_or_null(); 498 499 virtual oop protection_domain() const = 0; 500 501 oop class_loader() const; 502 503 // This loads the klass's holder as a phantom. This is useful when a weak Klass 504 // pointer has been "peeked" and then must be kept alive before it may 505 // be used safely. All uses of klass_holder need to apply the appropriate barriers, 506 // except during GC. klass_holder() const507 oop klass_holder() const { return class_loader_data()->holder_phantom(); } 508 509 protected: 510 virtual Klass* array_klass_impl(bool or_null, int rank, TRAPS); 511 virtual Klass* array_klass_impl(bool or_null, TRAPS); 512 513 // Error handling when length > max_length or length < 0 514 static void check_array_allocation_length(int length, int max_length, TRAPS); 515 set_vtable_length(int len)516 void set_vtable_length(int len) { _vtable_len= len; } 517 518 vtableEntry* start_of_vtable() const; 519 public: 520 Method* method_at_vtable(int index); 521 522 static ByteSize vtable_start_offset(); vtable_length_offset()523 static ByteSize vtable_length_offset() { 524 return byte_offset_of(Klass, _vtable_len); 525 } 526 527 // CDS support - remove and restore oops from metadata. Oops are not shared. 528 virtual void remove_unshareable_info(); 529 virtual void remove_java_mirror(); 530 virtual void restore_unshareable_info(ClassLoaderData* loader_data, Handle protection_domain, TRAPS); 531 532 protected: 533 // computes the subtype relationship 534 virtual bool compute_is_subtype_of(Klass* k); 535 public: 536 // subclass accessor (here for convenience; undefined for non-klass objects) is_leaf_class() const537 virtual bool is_leaf_class() const { fatal("not a class"); return false; } 538 public: 539 // ALL FUNCTIONS BELOW THIS POINT ARE DISPATCHED FROM AN OOP 540 // These functions describe behavior for the oop not the KLASS. 541 542 // actual oop size of obj in memory 543 virtual int oop_size(oop obj) const = 0; 544 545 // Size of klass in word size. 546 virtual int size() const = 0; 547 #if INCLUDE_SERVICES 548 virtual void collect_statistics(KlassSizeStats *sz) const; 549 #endif 550 551 // Returns the Java name for a class (Resource allocated) 552 // For arrays, this returns the name of the element with a leading '['. 553 // For classes, this returns the name with the package separators 554 // turned into '.'s. 555 const char* external_name() const; 556 // Returns the name for a class (Resource allocated) as the class 557 // would appear in a signature. 558 // For arrays, this returns the name of the element with a leading '['. 559 // For classes, this returns the name with a leading 'L' and a trailing ';' 560 // and the package separators as '/'. 561 virtual const char* signature_name() const; 562 563 const char* joint_in_module_of_loader(const Klass* class2, bool include_parent_loader = false) const; 564 const char* class_in_module_of_loader(bool use_are = false, bool include_parent_loader = false) const; 565 566 // Returns "interface", "abstract class" or "class". 567 const char* external_kind() const; 568 569 // type testing operations 570 #ifdef ASSERT 571 protected: is_instance_klass_slow() const572 virtual bool is_instance_klass_slow() const { return false; } is_array_klass_slow() const573 virtual bool is_array_klass_slow() const { return false; } is_objArray_klass_slow() const574 virtual bool is_objArray_klass_slow() const { return false; } is_typeArray_klass_slow() const575 virtual bool is_typeArray_klass_slow() const { return false; } 576 #endif // ASSERT 577 public: 578 579 // Fast non-virtual versions 580 #ifndef ASSERT 581 #define assert_same_query(xval, xcheck) xval 582 #else 583 private: 584 static bool assert_same_query(bool xval, bool xslow) { 585 assert(xval == xslow, "slow and fast queries agree"); 586 return xval; 587 } 588 public: 589 #endif is_instance_klass() const590 inline bool is_instance_klass() const { return assert_same_query( 591 layout_helper_is_instance(layout_helper()), 592 is_instance_klass_slow()); } is_array_klass() const593 inline bool is_array_klass() const { return assert_same_query( 594 layout_helper_is_array(layout_helper()), 595 is_array_klass_slow()); } is_objArray_klass() const596 inline bool is_objArray_klass() const { return assert_same_query( 597 layout_helper_is_objArray(layout_helper()), 598 is_objArray_klass_slow()); } is_typeArray_klass() const599 inline bool is_typeArray_klass() const { return assert_same_query( 600 layout_helper_is_typeArray(layout_helper()), 601 is_typeArray_klass_slow()); } 602 #undef assert_same_query 603 604 // Access flags access_flags() const605 AccessFlags access_flags() const { return _access_flags; } set_access_flags(AccessFlags flags)606 void set_access_flags(AccessFlags flags) { _access_flags = flags; } 607 is_public() const608 bool is_public() const { return _access_flags.is_public(); } is_final() const609 bool is_final() const { return _access_flags.is_final(); } is_interface() const610 bool is_interface() const { return _access_flags.is_interface(); } is_abstract() const611 bool is_abstract() const { return _access_flags.is_abstract(); } is_super() const612 bool is_super() const { return _access_flags.is_super(); } is_synthetic() const613 bool is_synthetic() const { return _access_flags.is_synthetic(); } set_is_synthetic()614 void set_is_synthetic() { _access_flags.set_is_synthetic(); } has_finalizer() const615 bool has_finalizer() const { return _access_flags.has_finalizer(); } has_final_method() const616 bool has_final_method() const { return _access_flags.has_final_method(); } set_has_finalizer()617 void set_has_finalizer() { _access_flags.set_has_finalizer(); } set_has_final_method()618 void set_has_final_method() { _access_flags.set_has_final_method(); } has_vanilla_constructor() const619 bool has_vanilla_constructor() const { return _access_flags.has_vanilla_constructor(); } set_has_vanilla_constructor()620 void set_has_vanilla_constructor() { _access_flags.set_has_vanilla_constructor(); } has_miranda_methods() const621 bool has_miranda_methods () const { return access_flags().has_miranda_methods(); } set_has_miranda_methods()622 void set_has_miranda_methods() { _access_flags.set_has_miranda_methods(); } is_shared() const623 bool is_shared() const { return access_flags().is_shared_class(); } // shadows MetaspaceObj::is_shared)() set_is_shared()624 void set_is_shared() { _access_flags.set_is_shared_class(); } 625 626 bool is_cloneable() const; 627 void set_is_cloneable(); 628 629 // Biased locking support 630 // Note: the prototype header is always set up to be at least the 631 // prototype markOop. If biased locking is enabled it may further be 632 // biasable and have an epoch. prototype_header() const633 markOop prototype_header() const { return _prototype_header; } 634 // NOTE: once instances of this klass are floating around in the 635 // system, this header must only be updated at a safepoint. 636 // NOTE 2: currently we only ever set the prototype header to the 637 // biasable prototype for instanceKlasses. There is no technical 638 // reason why it could not be done for arrayKlasses aside from 639 // wanting to reduce the initial scope of this optimization. There 640 // are potential problems in setting the bias pattern for 641 // JVM-internal oops. 642 inline void set_prototype_header(markOop header); prototype_header_offset()643 static ByteSize prototype_header_offset() { return in_ByteSize(offset_of(Klass, _prototype_header)); } 644 biased_lock_revocation_count() const645 int biased_lock_revocation_count() const { return (int) _biased_lock_revocation_count; } 646 // Atomically increments biased_lock_revocation_count and returns updated value 647 int atomic_incr_biased_lock_revocation_count(); set_biased_lock_revocation_count(int val)648 void set_biased_lock_revocation_count(int val) { _biased_lock_revocation_count = (jint) val; } last_biased_lock_bulk_revocation_time()649 jlong last_biased_lock_bulk_revocation_time() { return _last_biased_lock_bulk_revocation_time; } set_last_biased_lock_bulk_revocation_time(jlong cur_time)650 void set_last_biased_lock_bulk_revocation_time(jlong cur_time) { _last_biased_lock_bulk_revocation_time = cur_time; } 651 652 JFR_ONLY(DEFINE_TRACE_ID_METHODS;) 653 654 virtual void metaspace_pointers_do(MetaspaceClosure* iter); type() const655 virtual MetaspaceObj::Type type() const { return ClassType; } 656 657 // Iff the class loader (or mirror for unsafe anonymous classes) is alive the 658 // Klass is considered alive. This is safe to call before the CLD is marked as 659 // unloading, and hence during concurrent class unloading. is_loader_alive() const660 bool is_loader_alive() const { return class_loader_data()->is_alive(); } 661 662 void clean_subklass(); 663 664 static void clean_weak_klass_links(bool unloading_occurred, bool clean_alive_klasses = true); clean_subklass_tree()665 static void clean_subklass_tree() { 666 clean_weak_klass_links(/*unloading_occurred*/ true , /* clean_alive_klasses */ false); 667 } 668 array_klasses_do(void f (Klass * k))669 virtual void array_klasses_do(void f(Klass* k)) {} 670 671 // Return self, except for abstract classes with exactly 1 672 // implementor. Then return the 1 concrete implementation. 673 Klass *up_cast_abstract(); 674 675 // klass name name() const676 Symbol* name() const { return _name; } 677 void set_name(Symbol* n); 678 679 public: 680 // jvm support 681 virtual jint compute_modifier_flags(TRAPS) const; 682 683 // JVMTI support 684 virtual jint jvmti_class_status() const; 685 686 // Printing 687 virtual void print_on(outputStream* st) const; 688 689 virtual void oop_print_value_on(oop obj, outputStream* st); 690 virtual void oop_print_on (oop obj, outputStream* st); 691 692 virtual const char* internal_name() const = 0; 693 694 // Verification 695 virtual void verify_on(outputStream* st); verify()696 void verify() { verify_on(tty); } 697 698 #ifndef PRODUCT 699 bool verify_vtable_index(int index); 700 #endif 701 702 virtual void oop_verify_on(oop obj, outputStream* st); 703 704 // for error reporting 705 static Klass* decode_klass_raw(narrowKlass narrow_klass); 706 static bool is_valid(Klass* k); 707 708 static bool is_null(narrowKlass obj); 709 static bool is_null(Klass* obj); 710 711 // klass encoding for klass pointer in objects. 712 static narrowKlass encode_klass_not_null(Klass* v); 713 static narrowKlass encode_klass(Klass* v); 714 715 static Klass* decode_klass_not_null(narrowKlass v); 716 static Klass* decode_klass(narrowKlass v); 717 }; 718 719 #endif // SHARE_VM_OOPS_KLASS_HPP 720