klass.hpp revision 2062:3582bf76420e
1/* 2 * Copyright (c) 1997, 2010, 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/klassOop.hpp" 33#include "oops/klassPS.hpp" 34#include "oops/oop.hpp" 35#include "runtime/orderAccess.hpp" 36#include "utilities/accessFlags.hpp" 37#ifndef SERIALGC 38#include "gc_implementation/concurrentMarkSweep/cmsOopClosures.hpp" 39#include "gc_implementation/g1/g1OopClosures.hpp" 40#include "gc_implementation/parNew/parOopClosures.hpp" 41#endif 42 43// A Klass is the part of the klassOop that provides: 44// 1: language level class object (method dictionary etc.) 45// 2: provide vm dispatch behavior for the object 46// Both functions are combined into one C++ class. The toplevel class "Klass" 47// implements purpose 1 whereas all subclasses provide extra virtual functions 48// for purpose 2. 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// Klass layout: 59// [header ] klassOop 60// [klass pointer ] klassOop 61// [C++ vtbl ptr ] (contained in Klass_vtbl) 62// [layout_helper ] 63// [super_check_offset ] for fast subtype checks 64// [secondary_super_cache] for fast subtype checks 65// [secondary_supers ] array of 2ndary supertypes 66// [primary_supers 0] 67// [primary_supers 1] 68// [primary_supers 2] 69// ... 70// [primary_supers 7] 71// [java_mirror ] 72// [super ] 73// [name ] 74// [first subklass] 75// [next_sibling ] link to chain additional subklasses 76// [modifier_flags] 77// [access_flags ] 78// [verify_count ] - not in product 79// [alloc_count ] 80// [last_biased_lock_bulk_revocation_time] (64 bits) 81// [prototype_header] 82// [biased_lock_revocation_count] 83 84 85// Forward declarations. 86class klassVtable; 87class KlassHandle; 88class OrderAccess; 89 90// Holder (or cage) for the C++ vtable of each kind of Klass. 91// We want to tightly constrain the location of the C++ vtable in the overall layout. 92class Klass_vtbl { 93 protected: 94 // The following virtual exists only to force creation of a C++ vtable, 95 // so that this class truly is the location of the vtable of all Klasses. 96 virtual void unused_initial_virtual() { } 97 98 public: 99 // The following virtual makes Klass_vtbl play a second role as a 100 // factory protocol for subclasses of Klass ("sub-Klasses"). 101 // Here's how it works.... 102 // 103 // This VM uses metaobjects as factories for their instances. 104 // 105 // In order to initialize the C++ vtable of a new instance, its 106 // metaobject is forced to use the C++ placed new operator to 107 // allocate the instance. In a typical C++-based system, each 108 // sub-class would have its own factory routine which 109 // directly uses the placed new operator on the desired class, 110 // and then calls the appropriate chain of C++ constructors. 111 // 112 // However, this system uses shared code to performs the first 113 // allocation and initialization steps for all sub-Klasses. 114 // (See base_create_klass() and base_create_array_klass().) 115 // This does not factor neatly into a hierarchy of C++ constructors. 116 // Each caller of these shared "base_create" routines knows 117 // exactly which sub-Klass it is creating, but the shared routine 118 // does not, even though it must perform the actual allocation. 119 // 120 // Therefore, the caller of the shared "base_create" must wrap 121 // the specific placed new call in a virtual function which 122 // performs the actual allocation and vtable set-up. That 123 // virtual function is here, Klass_vtbl::allocate_permanent. 124 // 125 // The arguments to Universe::allocate_permanent() are passed 126 // straight through the placed new operator, which in turn 127 // obtains them directly from this virtual call. 128 // 129 // This virtual is called on a temporary "example instance" of the 130 // sub-Klass being instantiated, a C++ auto variable. The "real" 131 // instance created by this virtual is on the VM heap, where it is 132 // equipped with a klassOopDesc header. 133 // 134 // It is merely an accident of implementation that we use "example 135 // instances", but that is why the virtual function which implements 136 // each sub-Klass factory happens to be defined by the same sub-Klass 137 // for which it creates instances. 138 // 139 // The vtbl_value() call (see below) is used to strip away the 140 // accidental Klass-ness from an "example instance" and present it as 141 // a factory. Think of each factory object as a mere container of the 142 // C++ vtable for the desired sub-Klass. Since C++ does not allow 143 // direct references to vtables, the factory must also be delegated 144 // the task of allocating the instance, but the essential point is 145 // that the factory knows how to initialize the C++ vtable with the 146 // right pointer value. All other common initializations are handled 147 // by the shared "base_create" subroutines. 148 // 149 virtual void* allocate_permanent(KlassHandle& klass, int size, TRAPS) const = 0; 150 void post_new_init_klass(KlassHandle& klass, klassOop obj, int size) const; 151 152 // Every subclass on which vtbl_value is called must include this macro. 153 // Delay the installation of the klassKlass pointer until after the 154 // the vtable for a new klass has been installed (after the call to new()). 155#define DEFINE_ALLOCATE_PERMANENT(thisKlass) \ 156 void* allocate_permanent(KlassHandle& klass_klass, int size, TRAPS) const { \ 157 void* result = new(klass_klass, size, THREAD) thisKlass(); \ 158 if (HAS_PENDING_EXCEPTION) return NULL; \ 159 klassOop new_klass = ((Klass*) result)->as_klassOop(); \ 160 OrderAccess::storestore(); \ 161 post_new_init_klass(klass_klass, new_klass, size); \ 162 return result; \ 163 } 164 165 bool null_vtbl() { return *(intptr_t*)this == 0; } 166 167 protected: 168 void* operator new(size_t ignored, KlassHandle& klass, int size, TRAPS); 169}; 170 171 172class Klass : public Klass_vtbl { 173 friend class VMStructs; 174 protected: 175 // note: put frequently-used fields together at start of klass structure 176 // for better cache behavior (may not make much of a difference but sure won't hurt) 177 enum { _primary_super_limit = 8 }; 178 179 // The "layout helper" is a combined descriptor of object layout. 180 // For klasses which are neither instance nor array, the value is zero. 181 // 182 // For instances, layout helper is a positive number, the instance size. 183 // This size is already passed through align_object_size and scaled to bytes. 184 // The low order bit is set if instances of this class cannot be 185 // allocated using the fastpath. 186 // 187 // For arrays, layout helper is a negative number, containing four 188 // distinct bytes, as follows: 189 // MSB:[tag, hsz, ebt, log2(esz)]:LSB 190 // where: 191 // tag is 0x80 if the elements are oops, 0xC0 if non-oops 192 // hsz is array header size in bytes (i.e., offset of first element) 193 // ebt is the BasicType of the elements 194 // esz is the element size in bytes 195 // This packed word is arranged so as to be quickly unpacked by the 196 // various fast paths that use the various subfields. 197 // 198 // The esz bits can be used directly by a SLL instruction, without masking. 199 // 200 // Note that the array-kind tag looks like 0x00 for instance klasses, 201 // since their length in bytes is always less than 24Mb. 202 // 203 // Final note: This comes first, immediately after Klass_vtbl, 204 // because it is frequently queried. 205 jint _layout_helper; 206 207 // The fields _super_check_offset, _secondary_super_cache, _secondary_supers 208 // and _primary_supers all help make fast subtype checks. See big discussion 209 // in doc/server_compiler/checktype.txt 210 // 211 // Where to look to observe a supertype (it is &_secondary_super_cache for 212 // secondary supers, else is &_primary_supers[depth()]. 213 juint _super_check_offset; 214 215 // Class name. Instance classes: java/lang/String, etc. Array classes: [I, 216 // [Ljava/lang/String;, etc. Set to zero for all other kinds of classes. 217 Symbol* _name; 218 219 public: 220 oop* oop_block_beg() const { return adr_secondary_super_cache(); } 221 oop* oop_block_end() const { return adr_next_sibling() + 1; } 222 223 protected: 224 // 225 // The oop block. All oop fields must be declared here and only oop fields 226 // may be declared here. In addition, the first and last fields in this block 227 // must remain first and last, unless oop_block_beg() and/or oop_block_end() 228 // are updated. Grouping the oop fields in a single block simplifies oop 229 // iteration. 230 // 231 232 // Cache of last observed secondary supertype 233 klassOop _secondary_super_cache; 234 // Array of all secondary supertypes 235 objArrayOop _secondary_supers; 236 // Ordered list of all primary supertypes 237 klassOop _primary_supers[_primary_super_limit]; 238 // java/lang/Class instance mirroring this class 239 oop _java_mirror; 240 // Superclass 241 klassOop _super; 242 // First subclass (NULL if none); _subklass->next_sibling() is next one 243 klassOop _subklass; 244 // Sibling link (or NULL); links all subklasses of a klass 245 klassOop _next_sibling; 246 247 // 248 // End of the oop block. 249 // 250 251 jint _modifier_flags; // Processed access flags, for use by Class.getModifiers. 252 AccessFlags _access_flags; // Access flags. The class/interface distinction is stored here. 253 254#ifndef PRODUCT 255 int _verify_count; // to avoid redundant verifies 256#endif 257 258 juint _alloc_count; // allocation profiling support - update klass_size_in_bytes() if moved/deleted 259 260 // Biased locking implementation and statistics 261 // (the 64-bit chunk goes first, to avoid some fragmentation) 262 jlong _last_biased_lock_bulk_revocation_time; 263 markOop _prototype_header; // Used when biased locking is both enabled and disabled for this type 264 jint _biased_lock_revocation_count; 265 266 public: 267 268 // returns the enclosing klassOop 269 klassOop as_klassOop() const { 270 // see klassOop.hpp for layout. 271 return (klassOop) (((char*) this) - sizeof(klassOopDesc)); 272 } 273 274 public: 275 // Allocation 276 const Klass_vtbl& vtbl_value() const { return *this; } // used only on "example instances" 277 static KlassHandle base_create_klass(KlassHandle& klass, int size, const Klass_vtbl& vtbl, TRAPS); 278 static klassOop base_create_klass_oop(KlassHandle& klass, int size, const Klass_vtbl& vtbl, TRAPS); 279 280 // super 281 klassOop super() const { return _super; } 282 void set_super(klassOop k) { oop_store_without_check((oop*) &_super, (oop) k); } 283 284 // initializes _super link, _primary_supers & _secondary_supers arrays 285 void initialize_supers(klassOop k, TRAPS); 286 void initialize_supers_impl1(klassOop k); 287 void initialize_supers_impl2(klassOop k); 288 289 // klass-specific helper for initializing _secondary_supers 290 virtual objArrayOop compute_secondary_supers(int num_extra_slots, TRAPS); 291 292 // java_super is the Java-level super type as specified by Class.getSuperClass. 293 virtual klassOop java_super() const { return NULL; } 294 295 juint super_check_offset() const { return _super_check_offset; } 296 void set_super_check_offset(juint o) { _super_check_offset = o; } 297 298 klassOop secondary_super_cache() const { return _secondary_super_cache; } 299 void set_secondary_super_cache(klassOop k) { oop_store_without_check((oop*) &_secondary_super_cache, (oop) k); } 300 301 objArrayOop secondary_supers() const { return _secondary_supers; } 302 void set_secondary_supers(objArrayOop k) { oop_store_without_check((oop*) &_secondary_supers, (oop) k); } 303 304 // Return the element of the _super chain of the given depth. 305 // If there is no such element, return either NULL or this. 306 klassOop primary_super_of_depth(juint i) const { 307 assert(i < primary_super_limit(), "oob"); 308 klassOop super = _primary_supers[i]; 309 assert(super == NULL || super->klass_part()->super_depth() == i, "correct display"); 310 return super; 311 } 312 313 // Can this klass be a primary super? False for interfaces and arrays of 314 // interfaces. False also for arrays or classes with long super chains. 315 bool can_be_primary_super() const { 316 const juint secondary_offset = secondary_super_cache_offset_in_bytes() + sizeof(oopDesc); 317 return super_check_offset() != secondary_offset; 318 } 319 virtual bool can_be_primary_super_slow() const; 320 321 // Returns number of primary supers; may be a number in the inclusive range [0, primary_super_limit]. 322 juint super_depth() const { 323 if (!can_be_primary_super()) { 324 return primary_super_limit(); 325 } else { 326 juint d = (super_check_offset() - (primary_supers_offset_in_bytes() + sizeof(oopDesc))) / sizeof(klassOop); 327 assert(d < primary_super_limit(), "oob"); 328 assert(_primary_supers[d] == as_klassOop(), "proper init"); 329 return d; 330 } 331 } 332 333 // java mirror 334 oop java_mirror() const { return _java_mirror; } 335 void set_java_mirror(oop m) { oop_store((oop*) &_java_mirror, m); } 336 337 // modifier flags 338 jint modifier_flags() const { return _modifier_flags; } 339 void set_modifier_flags(jint flags) { _modifier_flags = flags; } 340 341 // size helper 342 int layout_helper() const { return _layout_helper; } 343 void set_layout_helper(int lh) { _layout_helper = lh; } 344 345 // Note: for instances layout_helper() may include padding. 346 // Use instanceKlass::contains_field_offset to classify field offsets. 347 348 // sub/superklass links 349 instanceKlass* superklass() const; 350 Klass* subklass() const; 351 Klass* next_sibling() const; 352 void append_to_sibling_list(); // add newly created receiver to superklass' subklass list 353 void remove_from_sibling_list(); // remove receiver from sibling list 354 protected: // internal accessors 355 klassOop subklass_oop() const { return _subklass; } 356 klassOop next_sibling_oop() const { return _next_sibling; } 357 void set_subklass(klassOop s); 358 void set_next_sibling(klassOop s); 359 360 oop* adr_super() const { return (oop*)&_super; } 361 oop* adr_primary_supers() const { return (oop*)&_primary_supers[0]; } 362 oop* adr_secondary_super_cache() const { return (oop*)&_secondary_super_cache; } 363 oop* adr_secondary_supers()const { return (oop*)&_secondary_supers; } 364 oop* adr_java_mirror() const { return (oop*)&_java_mirror; } 365 oop* adr_subklass() const { return (oop*)&_subklass; } 366 oop* adr_next_sibling() const { return (oop*)&_next_sibling; } 367 368 public: 369 // Allocation profiling support 370 juint alloc_count() const { return _alloc_count; } 371 void set_alloc_count(juint n) { _alloc_count = n; } 372 virtual juint alloc_size() const = 0; 373 virtual void set_alloc_size(juint n) = 0; 374 375 // Compiler support 376 static int super_offset_in_bytes() { return offset_of(Klass, _super); } 377 static int super_check_offset_offset_in_bytes() { return offset_of(Klass, _super_check_offset); } 378 static int primary_supers_offset_in_bytes(){ return offset_of(Klass, _primary_supers); } 379 static int secondary_super_cache_offset_in_bytes() { return offset_of(Klass, _secondary_super_cache); } 380 static int secondary_supers_offset_in_bytes() { return offset_of(Klass, _secondary_supers); } 381 static int java_mirror_offset_in_bytes() { return offset_of(Klass, _java_mirror); } 382 static int modifier_flags_offset_in_bytes(){ return offset_of(Klass, _modifier_flags); } 383 static int layout_helper_offset_in_bytes() { return offset_of(Klass, _layout_helper); } 384 static int access_flags_offset_in_bytes() { return offset_of(Klass, _access_flags); } 385 386 // Unpacking layout_helper: 387 enum { 388 _lh_neutral_value = 0, // neutral non-array non-instance value 389 _lh_instance_slow_path_bit = 0x01, 390 _lh_log2_element_size_shift = BitsPerByte*0, 391 _lh_log2_element_size_mask = BitsPerLong-1, 392 _lh_element_type_shift = BitsPerByte*1, 393 _lh_element_type_mask = right_n_bits(BitsPerByte), // shifted mask 394 _lh_header_size_shift = BitsPerByte*2, 395 _lh_header_size_mask = right_n_bits(BitsPerByte), // shifted mask 396 _lh_array_tag_bits = 2, 397 _lh_array_tag_shift = BitsPerInt - _lh_array_tag_bits, 398 _lh_array_tag_type_value = ~0x00, // 0xC0000000 >> 30 399 _lh_array_tag_obj_value = ~0x01 // 0x80000000 >> 30 400 }; 401 402 static int layout_helper_size_in_bytes(jint lh) { 403 assert(lh > (jint)_lh_neutral_value, "must be instance"); 404 return (int) lh & ~_lh_instance_slow_path_bit; 405 } 406 static bool layout_helper_needs_slow_path(jint lh) { 407 assert(lh > (jint)_lh_neutral_value, "must be instance"); 408 return (lh & _lh_instance_slow_path_bit) != 0; 409 } 410 static bool layout_helper_is_instance(jint lh) { 411 return (jint)lh > (jint)_lh_neutral_value; 412 } 413 static bool layout_helper_is_javaArray(jint lh) { 414 return (jint)lh < (jint)_lh_neutral_value; 415 } 416 static bool layout_helper_is_typeArray(jint lh) { 417 // _lh_array_tag_type_value == (lh >> _lh_array_tag_shift); 418 return (juint)lh >= (juint)(_lh_array_tag_type_value << _lh_array_tag_shift); 419 } 420 static bool layout_helper_is_objArray(jint lh) { 421 // _lh_array_tag_obj_value == (lh >> _lh_array_tag_shift); 422 return (jint)lh < (jint)(_lh_array_tag_type_value << _lh_array_tag_shift); 423 } 424 static int layout_helper_header_size(jint lh) { 425 assert(lh < (jint)_lh_neutral_value, "must be array"); 426 int hsize = (lh >> _lh_header_size_shift) & _lh_header_size_mask; 427 assert(hsize > 0 && hsize < (int)sizeof(oopDesc)*3, "sanity"); 428 return hsize; 429 } 430 static BasicType layout_helper_element_type(jint lh) { 431 assert(lh < (jint)_lh_neutral_value, "must be array"); 432 int btvalue = (lh >> _lh_element_type_shift) & _lh_element_type_mask; 433 assert(btvalue >= T_BOOLEAN && btvalue <= T_OBJECT, "sanity"); 434 return (BasicType) btvalue; 435 } 436 static int layout_helper_log2_element_size(jint lh) { 437 assert(lh < (jint)_lh_neutral_value, "must be array"); 438 int l2esz = (lh >> _lh_log2_element_size_shift) & _lh_log2_element_size_mask; 439 assert(l2esz <= LogBitsPerLong, "sanity"); 440 return l2esz; 441 } 442 static jint array_layout_helper(jint tag, int hsize, BasicType etype, int log2_esize) { 443 return (tag << _lh_array_tag_shift) 444 | (hsize << _lh_header_size_shift) 445 | ((int)etype << _lh_element_type_shift) 446 | (log2_esize << _lh_log2_element_size_shift); 447 } 448 static jint instance_layout_helper(jint size, bool slow_path_flag) { 449 return (size << LogHeapWordSize) 450 | (slow_path_flag ? _lh_instance_slow_path_bit : 0); 451 } 452 static int layout_helper_to_size_helper(jint lh) { 453 assert(lh > (jint)_lh_neutral_value, "must be instance"); 454 // Note that the following expression discards _lh_instance_slow_path_bit. 455 return lh >> LogHeapWordSize; 456 } 457 // Out-of-line version computes everything based on the etype: 458 static jint array_layout_helper(BasicType etype); 459 460 // What is the maximum number of primary superclasses any klass can have? 461#ifdef PRODUCT 462 static juint primary_super_limit() { return _primary_super_limit; } 463#else 464 static juint primary_super_limit() { 465 assert(FastSuperclassLimit <= _primary_super_limit, "parameter oob"); 466 return FastSuperclassLimit; 467 } 468#endif 469 470 // vtables 471 virtual klassVtable* vtable() const { return NULL; } 472 473 static int klass_size_in_bytes() { return offset_of(Klass, _alloc_count) + sizeof(juint); } // all "visible" fields 474 475 // subclass check 476 bool is_subclass_of(klassOop k) const; 477 // subtype check: true if is_subclass_of, or if k is interface and receiver implements it 478 bool is_subtype_of(klassOop k) const { 479 juint off = k->klass_part()->super_check_offset(); 480 klassOop sup = *(klassOop*)( (address)as_klassOop() + off ); 481 const juint secondary_offset = secondary_super_cache_offset_in_bytes() + sizeof(oopDesc); 482 if (sup == k) { 483 return true; 484 } else if (off != secondary_offset) { 485 return false; 486 } else { 487 return search_secondary_supers(k); 488 } 489 } 490 bool search_secondary_supers(klassOop k) const; 491 492 // Find LCA in class hierarchy 493 Klass *LCA( Klass *k ); 494 495 // Check whether reflection/jni/jvm code is allowed to instantiate this class; 496 // if not, throw either an Error or an Exception. 497 virtual void check_valid_for_instantiation(bool throwError, TRAPS); 498 499 // Casting 500 static Klass* cast(klassOop k) { 501 assert(k->is_klass(), "cast to Klass"); 502 return k->klass_part(); 503 } 504 505 // array copying 506 virtual void copy_array(arrayOop s, int src_pos, arrayOop d, int dst_pos, int length, TRAPS); 507 508 // tells if the class should be initialized 509 virtual bool should_be_initialized() const { return false; } 510 // initializes the klass 511 virtual void initialize(TRAPS); 512 // lookup operation for MethodLookupCache 513 friend class MethodLookupCache; 514 virtual methodOop uncached_lookup_method(Symbol* name, Symbol* signature) const; 515 public: 516 methodOop lookup_method(Symbol* name, Symbol* signature) const { 517 return uncached_lookup_method(name, signature); 518 } 519 520 // array class with specific rank 521 klassOop array_klass(int rank, TRAPS) { return array_klass_impl(false, rank, THREAD); } 522 523 // array class with this klass as element type 524 klassOop array_klass(TRAPS) { return array_klass_impl(false, THREAD); } 525 526 // These will return NULL instead of allocating on the heap: 527 // NB: these can block for a mutex, like other functions with TRAPS arg. 528 klassOop array_klass_or_null(int rank); 529 klassOop array_klass_or_null(); 530 531 virtual oop protection_domain() { return NULL; } 532 virtual oop class_loader() const { return NULL; } 533 534 protected: 535 virtual klassOop array_klass_impl(bool or_null, int rank, TRAPS); 536 virtual klassOop array_klass_impl(bool or_null, TRAPS); 537 538 public: 539 virtual void remove_unshareable_info(); 540 virtual void shared_symbols_iterate(SymbolClosure* closure); 541 542 protected: 543 // computes the subtype relationship 544 virtual bool compute_is_subtype_of(klassOop k); 545 public: 546 // subclass accessor (here for convenience; undefined for non-klass objects) 547 virtual bool is_leaf_class() const { fatal("not a class"); return false; } 548 public: 549 // ALL FUNCTIONS BELOW THIS POINT ARE DISPATCHED FROM AN OOP 550 // These functions describe behavior for the oop not the KLASS. 551 552 // actual oop size of obj in memory 553 virtual int oop_size(oop obj) const = 0; 554 555 // actual oop size of this klass in memory 556 virtual int klass_oop_size() const = 0; 557 558 // Returns the Java name for a class (Resource allocated) 559 // For arrays, this returns the name of the element with a leading '['. 560 // For classes, this returns the name with the package separators 561 // turned into '.'s. 562 const char* external_name() const; 563 // Returns the name for a class (Resource allocated) as the class 564 // would appear in a signature. 565 // For arrays, this returns the name of the element with a leading '['. 566 // For classes, this returns the name with a leading 'L' and a trailing ';' 567 // and the package separators as '/'. 568 virtual const char* signature_name() const; 569 570 // garbage collection support 571 virtual void oop_follow_contents(oop obj) = 0; 572 virtual int oop_adjust_pointers(oop obj) = 0; 573 574 // Parallel Scavenge and Parallel Old 575 PARALLEL_GC_DECLS_PV 576 577 public: 578 // type testing operations 579 virtual bool oop_is_instance_slow() const { return false; } 580 virtual bool oop_is_instanceRef() const { return false; } 581 virtual bool oop_is_array() const { return false; } 582 virtual bool oop_is_objArray_slow() const { return false; } 583 virtual bool oop_is_klass() const { return false; } 584 virtual bool oop_is_thread() const { return false; } 585 virtual bool oop_is_method() const { return false; } 586 virtual bool oop_is_constMethod() const { return false; } 587 virtual bool oop_is_methodData() const { return false; } 588 virtual bool oop_is_constantPool() const { return false; } 589 virtual bool oop_is_constantPoolCache() const { return false; } 590 virtual bool oop_is_typeArray_slow() const { return false; } 591 virtual bool oop_is_arrayKlass() const { return false; } 592 virtual bool oop_is_objArrayKlass() const { return false; } 593 virtual bool oop_is_typeArrayKlass() const { return false; } 594 virtual bool oop_is_compiledICHolder() const { return false; } 595 virtual bool oop_is_instanceKlass() const { return false; } 596 597 bool oop_is_javaArray_slow() const { 598 return oop_is_objArray_slow() || oop_is_typeArray_slow(); 599 } 600 601 // Fast non-virtual versions, used by oop.inline.hpp and elsewhere: 602 #ifndef ASSERT 603 #define assert_same_query(xval, xcheck) xval 604 #else 605 private: 606 static bool assert_same_query(bool xval, bool xslow) { 607 assert(xval == xslow, "slow and fast queries agree"); 608 return xval; 609 } 610 public: 611 #endif 612 inline bool oop_is_instance() const { return assert_same_query( 613 layout_helper_is_instance(layout_helper()), 614 oop_is_instance_slow()); } 615 inline bool oop_is_javaArray() const { return assert_same_query( 616 layout_helper_is_javaArray(layout_helper()), 617 oop_is_javaArray_slow()); } 618 inline bool oop_is_objArray() const { return assert_same_query( 619 layout_helper_is_objArray(layout_helper()), 620 oop_is_objArray_slow()); } 621 inline bool oop_is_typeArray() const { return assert_same_query( 622 layout_helper_is_typeArray(layout_helper()), 623 oop_is_typeArray_slow()); } 624 #undef assert_same_query 625 626 // Unless overridden, oop is parsable if it has a klass pointer. 627 // Parsability of an object is object specific. 628 virtual bool oop_is_parsable(oop obj) const { return true; } 629 630 // Unless overridden, oop is safe for concurrent GC processing 631 // after its allocation is complete. The exception to 632 // this is the case where objects are changed after allocation. 633 // Class redefinition is one of the known exceptions. During 634 // class redefinition, an allocated class can changed in order 635 // order to create a merged class (the combiniation of the 636 // old class definition that has to be perserved and the new class 637 // definition which is being created. 638 virtual bool oop_is_conc_safe(oop obj) const { return true; } 639 640 // Access flags 641 AccessFlags access_flags() const { return _access_flags; } 642 void set_access_flags(AccessFlags flags) { _access_flags = flags; } 643 644 bool is_public() const { return _access_flags.is_public(); } 645 bool is_final() const { return _access_flags.is_final(); } 646 bool is_interface() const { return _access_flags.is_interface(); } 647 bool is_abstract() const { return _access_flags.is_abstract(); } 648 bool is_super() const { return _access_flags.is_super(); } 649 bool is_synthetic() const { return _access_flags.is_synthetic(); } 650 void set_is_synthetic() { _access_flags.set_is_synthetic(); } 651 bool has_finalizer() const { return _access_flags.has_finalizer(); } 652 bool has_final_method() const { return _access_flags.has_final_method(); } 653 void set_has_finalizer() { _access_flags.set_has_finalizer(); } 654 void set_has_final_method() { _access_flags.set_has_final_method(); } 655 bool is_cloneable() const { return _access_flags.is_cloneable(); } 656 void set_is_cloneable() { _access_flags.set_is_cloneable(); } 657 bool has_vanilla_constructor() const { return _access_flags.has_vanilla_constructor(); } 658 void set_has_vanilla_constructor() { _access_flags.set_has_vanilla_constructor(); } 659 bool has_miranda_methods () const { return access_flags().has_miranda_methods(); } 660 void set_has_miranda_methods() { _access_flags.set_has_miranda_methods(); } 661 662 // Biased locking support 663 // Note: the prototype header is always set up to be at least the 664 // prototype markOop. If biased locking is enabled it may further be 665 // biasable and have an epoch. 666 markOop prototype_header() const { return _prototype_header; } 667 // NOTE: once instances of this klass are floating around in the 668 // system, this header must only be updated at a safepoint. 669 // NOTE 2: currently we only ever set the prototype header to the 670 // biasable prototype for instanceKlasses. There is no technical 671 // reason why it could not be done for arrayKlasses aside from 672 // wanting to reduce the initial scope of this optimization. There 673 // are potential problems in setting the bias pattern for 674 // JVM-internal oops. 675 inline void set_prototype_header(markOop header); 676 static int prototype_header_offset_in_bytes() { return offset_of(Klass, _prototype_header); } 677 678 int biased_lock_revocation_count() const { return (int) _biased_lock_revocation_count; } 679 // Atomically increments biased_lock_revocation_count and returns updated value 680 int atomic_incr_biased_lock_revocation_count(); 681 void set_biased_lock_revocation_count(int val) { _biased_lock_revocation_count = (jint) val; } 682 jlong last_biased_lock_bulk_revocation_time() { return _last_biased_lock_bulk_revocation_time; } 683 void set_last_biased_lock_bulk_revocation_time(jlong cur_time) { _last_biased_lock_bulk_revocation_time = cur_time; } 684 685 686 // garbage collection support 687 virtual void follow_weak_klass_links( 688 BoolObjectClosure* is_alive, OopClosure* keep_alive); 689 690 // Prefetch within oop iterators. This is a macro because we 691 // can't guarantee that the compiler will inline it. In 64-bit 692 // it generally doesn't. Signature is 693 // 694 // static void prefetch_beyond(oop* const start, 695 // oop* const end, 696 // const intx foffset, 697 // const Prefetch::style pstyle); 698#define prefetch_beyond(start, end, foffset, pstyle) { \ 699 const intx foffset_ = (foffset); \ 700 const Prefetch::style pstyle_ = (pstyle); \ 701 assert(foffset_ > 0, "prefetch beyond, not behind"); \ 702 if (pstyle_ != Prefetch::do_none) { \ 703 oop* ref = (start); \ 704 if (ref < (end)) { \ 705 switch (pstyle_) { \ 706 case Prefetch::do_read: \ 707 Prefetch::read(*ref, foffset_); \ 708 break; \ 709 case Prefetch::do_write: \ 710 Prefetch::write(*ref, foffset_); \ 711 break; \ 712 default: \ 713 ShouldNotReachHere(); \ 714 break; \ 715 } \ 716 } \ 717 } \ 718 } 719 720 // iterators 721 virtual int oop_oop_iterate(oop obj, OopClosure* blk) = 0; 722 virtual int oop_oop_iterate_v(oop obj, OopClosure* blk) { 723 return oop_oop_iterate(obj, blk); 724 } 725 726#ifndef SERIALGC 727 // In case we don't have a specialized backward scanner use forward 728 // iteration. 729 virtual int oop_oop_iterate_backwards_v(oop obj, OopClosure* blk) { 730 return oop_oop_iterate_v(obj, blk); 731 } 732#endif // !SERIALGC 733 734 // Iterates "blk" over all the oops in "obj" (of type "this") within "mr". 735 // (I don't see why the _m should be required, but without it the Solaris 736 // C++ gives warning messages about overridings of the "oop_oop_iterate" 737 // defined above "hiding" this virtual function. (DLD, 6/20/00)) */ 738 virtual int oop_oop_iterate_m(oop obj, OopClosure* blk, MemRegion mr) = 0; 739 virtual int oop_oop_iterate_v_m(oop obj, OopClosure* blk, MemRegion mr) { 740 return oop_oop_iterate_m(obj, blk, mr); 741 } 742 743 // Versions of the above iterators specialized to particular subtypes 744 // of OopClosure, to avoid closure virtual calls. 745#define Klass_OOP_OOP_ITERATE_DECL(OopClosureType, nv_suffix) \ 746 virtual int oop_oop_iterate##nv_suffix(oop obj, OopClosureType* blk) { \ 747 /* Default implementation reverts to general version. */ \ 748 return oop_oop_iterate(obj, blk); \ 749 } \ 750 \ 751 /* Iterates "blk" over all the oops in "obj" (of type "this") within "mr". \ 752 (I don't see why the _m should be required, but without it the Solaris \ 753 C++ gives warning messages about overridings of the "oop_oop_iterate" \ 754 defined above "hiding" this virtual function. (DLD, 6/20/00)) */ \ 755 virtual int oop_oop_iterate##nv_suffix##_m(oop obj, \ 756 OopClosureType* blk, \ 757 MemRegion mr) { \ 758 return oop_oop_iterate_m(obj, blk, mr); \ 759 } 760 761 SPECIALIZED_OOP_OOP_ITERATE_CLOSURES_1(Klass_OOP_OOP_ITERATE_DECL) 762 SPECIALIZED_OOP_OOP_ITERATE_CLOSURES_2(Klass_OOP_OOP_ITERATE_DECL) 763 764#ifndef SERIALGC 765#define Klass_OOP_OOP_ITERATE_BACKWARDS_DECL(OopClosureType, nv_suffix) \ 766 virtual int oop_oop_iterate_backwards##nv_suffix(oop obj, \ 767 OopClosureType* blk) { \ 768 /* Default implementation reverts to general version. */ \ 769 return oop_oop_iterate_backwards_v(obj, blk); \ 770 } 771 772 SPECIALIZED_OOP_OOP_ITERATE_CLOSURES_1(Klass_OOP_OOP_ITERATE_BACKWARDS_DECL) 773 SPECIALIZED_OOP_OOP_ITERATE_CLOSURES_2(Klass_OOP_OOP_ITERATE_BACKWARDS_DECL) 774#endif // !SERIALGC 775 776 virtual void array_klasses_do(void f(klassOop k)) {} 777 virtual void with_array_klasses_do(void f(klassOop k)); 778 779 // Return self, except for abstract classes with exactly 1 780 // implementor. Then return the 1 concrete implementation. 781 Klass *up_cast_abstract(); 782 783 // klass name 784 Symbol* name() const { return _name; } 785 void set_name(Symbol* n); 786 787 friend class klassKlass; 788 789 public: 790 // jvm support 791 virtual jint compute_modifier_flags(TRAPS) const; 792 793 // JVMTI support 794 virtual jint jvmti_class_status() const; 795 796 // Printing 797 virtual void oop_print_value_on(oop obj, outputStream* st); 798 virtual void oop_print_on (oop obj, outputStream* st); 799 800 // Verification 801 virtual const char* internal_name() const = 0; 802 virtual void oop_verify_on(oop obj, outputStream* st); 803 virtual void oop_verify_old_oop(oop obj, oop* p, bool allow_dirty); 804 virtual void oop_verify_old_oop(oop obj, narrowOop* p, bool allow_dirty); 805 // tells whether obj is partially constructed (gc during class loading) 806 virtual bool oop_partially_loaded(oop obj) const { return false; } 807 virtual void oop_set_partially_loaded(oop obj) {}; 808 809#ifndef PRODUCT 810 void verify_vtable_index(int index); 811#endif 812}; 813 814#endif // SHARE_VM_OOPS_KLASS_HPP 815