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 #include "precompiled.hpp" 26 #include "classfile/systemDictionary.hpp" 27 #include "classfile/vmSymbols.hpp" 28 #include "gc_interface/collectedHeap.inline.hpp" 29 #include "memory/oopFactory.hpp" 30 #include "memory/resourceArea.hpp" 31 #include "oops/instanceKlass.hpp" 32 #include "oops/klass.inline.hpp" 33 #include "oops/klassOop.hpp" 34 #include "oops/oop.inline.hpp" 35 #include "oops/oop.inline2.hpp" 36 #include "runtime/atomic.hpp" 37 38 39 bool Klass::is_subclass_of(klassOop k) const { 40 // Run up the super chain and check 41 klassOop t = as_klassOop(); 42 43 if (t == k) return true; 44 t = Klass::cast(t)->super(); 45 46 while (t != NULL) { 47 if (t == k) return true; 48 t = Klass::cast(t)->super(); 49 } 50 return false; 51 } 52 53 bool Klass::search_secondary_supers(klassOop k) const { 54 // Put some extra logic here out-of-line, before the search proper. 55 // This cuts down the size of the inline method. 56 57 // This is necessary, since I am never in my own secondary_super list. 58 if (this->as_klassOop() == k) 59 return true; 60 // Scan the array-of-objects for a match 61 int cnt = secondary_supers()->length(); 62 for (int i = 0; i < cnt; i++) { 63 if (secondary_supers()->obj_at(i) == k) { 64 ((Klass*)this)->set_secondary_super_cache(k); 65 return true; 66 } 67 } 68 return false; 69 } 70 71 // Return self, except for abstract classes with exactly 1 72 // implementor. Then return the 1 concrete implementation. 73 Klass *Klass::up_cast_abstract() { 74 Klass *r = this; 75 while( r->is_abstract() ) { // Receiver is abstract? 76 Klass *s = r->subklass(); // Check for exactly 1 subklass 77 if( !s || s->next_sibling() ) // Oops; wrong count; give up 78 return this; // Return 'this' as a no-progress flag 79 r = s; // Loop till find concrete class 80 } 81 return r; // Return the 1 concrete class 82 } 83 84 // Find LCA in class hierarchy 85 Klass *Klass::LCA( Klass *k2 ) { 86 Klass *k1 = this; 87 while( 1 ) { 88 if( k1->is_subtype_of(k2->as_klassOop()) ) return k2; 89 if( k2->is_subtype_of(k1->as_klassOop()) ) return k1; 90 k1 = k1->super()->klass_part(); 91 k2 = k2->super()->klass_part(); 92 } 93 } 94 95 96 void Klass::check_valid_for_instantiation(bool throwError, TRAPS) { 97 ResourceMark rm(THREAD); 98 THROW_MSG(throwError ? vmSymbols::java_lang_InstantiationError() 99 : vmSymbols::java_lang_InstantiationException(), external_name()); 100 } 101 102 103 void Klass::copy_array(arrayOop s, int src_pos, arrayOop d, int dst_pos, int length, TRAPS) { 104 THROW(vmSymbols::java_lang_ArrayStoreException()); 105 } 106 107 108 void Klass::initialize(TRAPS) { 109 ShouldNotReachHere(); 110 } 111 112 bool Klass::compute_is_subtype_of(klassOop k) { 113 assert(k->is_klass(), "argument must be a class"); 114 return is_subclass_of(k); 115 } 116 117 118 methodOop Klass::uncached_lookup_method(symbolOop name, symbolOop signature) const { 119 #ifdef ASSERT 120 tty->print_cr("Error: uncached_lookup_method called on a klass oop." 121 " Likely error: reflection method does not correctly" 122 " wrap return value in a mirror object."); 123 #endif 124 ShouldNotReachHere(); 125 return NULL; 126 } 127 128 klassOop Klass::base_create_klass_oop(KlassHandle& klass, int size, 129 const Klass_vtbl& vtbl, TRAPS) { 130 size = align_object_size(size); 131 // allocate and initialize vtable 132 Klass* kl = (Klass*) vtbl.allocate_permanent(klass, size, CHECK_NULL); 133 klassOop k = kl->as_klassOop(); 134 135 { // Preinitialize supertype information. 136 // A later call to initialize_supers() may update these settings: 137 kl->set_super(NULL); 138 for (juint i = 0; i < Klass::primary_super_limit(); i++) { 139 kl->_primary_supers[i] = NULL; 140 } 141 kl->set_secondary_supers(NULL); 142 oop_store_without_check((oop*) &kl->_primary_supers[0], k); 143 kl->set_super_check_offset(primary_supers_offset_in_bytes() + sizeof(oopDesc)); 144 } 145 146 kl->set_java_mirror(NULL); 147 kl->set_modifier_flags(0); 148 kl->set_layout_helper(Klass::_lh_neutral_value); 149 kl->set_name(NULL); 150 AccessFlags af; 151 af.set_flags(0); 152 kl->set_access_flags(af); 153 kl->set_subklass(NULL); 154 kl->set_next_sibling(NULL); 155 kl->set_alloc_count(0); 156 kl->set_alloc_size(0); 157 158 kl->set_prototype_header(markOopDesc::prototype()); 159 kl->set_biased_lock_revocation_count(0); 160 kl->set_last_biased_lock_bulk_revocation_time(0); 161 162 return k; 163 } 164 165 KlassHandle Klass::base_create_klass(KlassHandle& klass, int size, 166 const Klass_vtbl& vtbl, TRAPS) { 167 klassOop ek = base_create_klass_oop(klass, size, vtbl, THREAD); 168 return KlassHandle(THREAD, ek); 169 } 170 171 void Klass_vtbl::post_new_init_klass(KlassHandle& klass, 172 klassOop new_klass, 173 int size) const { 174 assert(!new_klass->klass_part()->null_vtbl(), "Not a complete klass"); 175 CollectedHeap::post_allocation_install_obj_klass(klass, new_klass, size); 176 } 177 178 void* Klass_vtbl::operator new(size_t ignored, KlassHandle& klass, 179 int size, TRAPS) { 180 // The vtable pointer is installed during the execution of 181 // constructors in the call to permanent_obj_allocate(). Delay 182 // the installation of the klass pointer into the new klass "k" 183 // until after the vtable pointer has been installed (i.e., until 184 // after the return of permanent_obj_allocate(). 185 klassOop k = 186 (klassOop) CollectedHeap::permanent_obj_allocate_no_klass_install(klass, 187 size, CHECK_NULL); 188 return k->klass_part(); 189 } 190 191 jint Klass::array_layout_helper(BasicType etype) { 192 assert(etype >= T_BOOLEAN && etype <= T_OBJECT, "valid etype"); 193 // Note that T_ARRAY is not allowed here. 194 int hsize = arrayOopDesc::base_offset_in_bytes(etype); 195 int esize = type2aelembytes(etype); 196 bool isobj = (etype == T_OBJECT); 197 int tag = isobj ? _lh_array_tag_obj_value : _lh_array_tag_type_value; 198 int lh = array_layout_helper(tag, hsize, etype, exact_log2(esize)); 199 200 assert(lh < (int)_lh_neutral_value, "must look like an array layout"); 201 assert(layout_helper_is_javaArray(lh), "correct kind"); 202 assert(layout_helper_is_objArray(lh) == isobj, "correct kind"); 203 assert(layout_helper_is_typeArray(lh) == !isobj, "correct kind"); 204 assert(layout_helper_header_size(lh) == hsize, "correct decode"); 205 assert(layout_helper_element_type(lh) == etype, "correct decode"); 206 assert(1 << layout_helper_log2_element_size(lh) == esize, "correct decode"); 207 208 return lh; 209 } 210 211 bool Klass::can_be_primary_super_slow() const { 212 if (super() == NULL) 213 return true; 214 else if (super()->klass_part()->super_depth() >= primary_super_limit()-1) 215 return false; 216 else 217 return true; 218 } 219 220 void Klass::initialize_supers(klassOop k, TRAPS) { 221 if (FastSuperclassLimit == 0) { 222 // None of the other machinery matters. 223 set_super(k); 224 return; 225 } 226 if (k == NULL) { 227 set_super(NULL); 228 oop_store_without_check((oop*) &_primary_supers[0], (oop) this->as_klassOop()); 229 assert(super_depth() == 0, "Object must already be initialized properly"); 230 } else if (k != super() || k == SystemDictionary::Object_klass()) { 231 assert(super() == NULL || super() == SystemDictionary::Object_klass(), 232 "initialize this only once to a non-trivial value"); 233 set_super(k); 234 Klass* sup = k->klass_part(); 235 int sup_depth = sup->super_depth(); 236 juint my_depth = MIN2(sup_depth + 1, (int)primary_super_limit()); 237 if (!can_be_primary_super_slow()) 238 my_depth = primary_super_limit(); 239 for (juint i = 0; i < my_depth; i++) { 240 oop_store_without_check((oop*) &_primary_supers[i], (oop) sup->_primary_supers[i]); 241 } 242 klassOop *super_check_cell; 243 if (my_depth < primary_super_limit()) { 244 oop_store_without_check((oop*) &_primary_supers[my_depth], (oop) this->as_klassOop()); 245 super_check_cell = &_primary_supers[my_depth]; 246 } else { 247 // Overflow of the primary_supers array forces me to be secondary. 248 super_check_cell = &_secondary_super_cache; 249 } 250 set_super_check_offset((address)super_check_cell - (address) this->as_klassOop()); 251 252 #ifdef ASSERT 253 { 254 juint j = super_depth(); 255 assert(j == my_depth, "computed accessor gets right answer"); 256 klassOop t = as_klassOop(); 257 while (!Klass::cast(t)->can_be_primary_super()) { 258 t = Klass::cast(t)->super(); 259 j = Klass::cast(t)->super_depth(); 260 } 261 for (juint j1 = j+1; j1 < primary_super_limit(); j1++) { 262 assert(primary_super_of_depth(j1) == NULL, "super list padding"); 263 } 264 while (t != NULL) { 265 assert(primary_super_of_depth(j) == t, "super list initialization"); 266 t = Klass::cast(t)->super(); 267 --j; 268 } 269 assert(j == (juint)-1, "correct depth count"); 270 } 271 #endif 272 } 273 274 if (secondary_supers() == NULL) { 275 KlassHandle this_kh (THREAD, this); 276 277 // Now compute the list of secondary supertypes. 278 // Secondaries can occasionally be on the super chain, 279 // if the inline "_primary_supers" array overflows. 280 int extras = 0; 281 klassOop p; 282 for (p = super(); !(p == NULL || p->klass_part()->can_be_primary_super()); p = p->klass_part()->super()) { 283 ++extras; 284 } 285 286 // Compute the "real" non-extra secondaries. 287 objArrayOop secondary_oops = compute_secondary_supers(extras, CHECK); 288 objArrayHandle secondaries (THREAD, secondary_oops); 289 290 // Store the extra secondaries in the first array positions: 291 int fillp = extras; 292 for (p = this_kh->super(); !(p == NULL || p->klass_part()->can_be_primary_super()); p = p->klass_part()->super()) { 293 int i; // Scan for overflow primaries being duplicates of 2nd'arys 294 295 // This happens frequently for very deeply nested arrays: the 296 // primary superclass chain overflows into the secondary. The 297 // secondary list contains the element_klass's secondaries with 298 // an extra array dimension added. If the element_klass's 299 // secondary list already contains some primary overflows, they 300 // (with the extra level of array-ness) will collide with the 301 // normal primary superclass overflows. 302 for( i = extras; i < secondaries->length(); i++ ) 303 if( secondaries->obj_at(i) == p ) 304 break; 305 if( i < secondaries->length() ) 306 continue; // It's a dup, don't put it in 307 secondaries->obj_at_put(--fillp, p); 308 } 309 // See if we had some dup's, so the array has holes in it. 310 if( fillp > 0 ) { 311 // Pack the array. Drop the old secondaries array on the floor 312 // and let GC reclaim it. 313 objArrayOop s2 = oopFactory::new_system_objArray(secondaries->length() - fillp, CHECK); 314 for( int i = 0; i < s2->length(); i++ ) 315 s2->obj_at_put( i, secondaries->obj_at(i+fillp) ); 316 secondaries = objArrayHandle(THREAD, s2); 317 } 318 319 #ifdef ASSERT 320 if (secondaries() != Universe::the_array_interfaces_array()) { 321 // We must not copy any NULL placeholders left over from bootstrap. 322 for (int j = 0; j < secondaries->length(); j++) { 323 assert(secondaries->obj_at(j) != NULL, "correct bootstrapping order"); 324 } 325 } 326 #endif 327 328 this_kh->set_secondary_supers(secondaries()); 329 } 330 } 331 332 objArrayOop Klass::compute_secondary_supers(int num_extra_slots, TRAPS) { 333 assert(num_extra_slots == 0, "override for complex klasses"); 334 return Universe::the_empty_system_obj_array(); 335 } 336 337 338 Klass* Klass::subklass() const { 339 return _subklass == NULL ? NULL : Klass::cast(_subklass); 340 } 341 342 instanceKlass* Klass::superklass() const { 343 assert(super() == NULL || super()->klass_part()->oop_is_instance(), "must be instance klass"); 344 return _super == NULL ? NULL : instanceKlass::cast(_super); 345 } 346 347 Klass* Klass::next_sibling() const { 348 return _next_sibling == NULL ? NULL : Klass::cast(_next_sibling); 349 } 350 351 void Klass::set_subklass(klassOop s) { 352 assert(s != as_klassOop(), "sanity check"); 353 oop_store_without_check((oop*)&_subklass, s); 354 } 355 356 void Klass::set_next_sibling(klassOop s) { 357 assert(s != as_klassOop(), "sanity check"); 358 oop_store_without_check((oop*)&_next_sibling, s); 359 } 360 361 void Klass::append_to_sibling_list() { 362 debug_only(if (!SharedSkipVerify) as_klassOop()->verify();) 363 // add ourselves to superklass' subklass list 364 instanceKlass* super = superklass(); 365 if (super == NULL) return; // special case: class Object 366 assert(SharedSkipVerify || 367 (!super->is_interface() // interfaces cannot be supers 368 && (super->superklass() == NULL || !is_interface())), 369 "an interface can only be a subklass of Object"); 370 klassOop prev_first_subklass = super->subklass_oop(); 371 if (prev_first_subklass != NULL) { 372 // set our sibling to be the superklass' previous first subklass 373 set_next_sibling(prev_first_subklass); 374 } 375 // make ourselves the superklass' first subklass 376 super->set_subklass(as_klassOop()); 377 debug_only(if (!SharedSkipVerify) as_klassOop()->verify();) 378 } 379 380 void Klass::remove_from_sibling_list() { 381 // remove receiver from sibling list 382 instanceKlass* super = superklass(); 383 assert(super != NULL || as_klassOop() == SystemDictionary::Object_klass(), "should have super"); 384 if (super == NULL) return; // special case: class Object 385 if (super->subklass() == this) { 386 // first subklass 387 super->set_subklass(_next_sibling); 388 } else { 389 Klass* sib = super->subklass(); 390 while (sib->next_sibling() != this) { 391 sib = sib->next_sibling(); 392 }; 393 sib->set_next_sibling(_next_sibling); 394 } 395 } 396 397 void Klass::follow_weak_klass_links( BoolObjectClosure* is_alive, OopClosure* keep_alive) { 398 // This klass is alive but the subklass and siblings are not followed/updated. 399 // We update the subklass link and the subklass' sibling links here. 400 // Our own sibling link will be updated by our superclass (which must be alive 401 // since we are). 402 assert(is_alive->do_object_b(as_klassOop()), "just checking, this should be live"); 403 if (ClassUnloading) { 404 klassOop sub = subklass_oop(); 405 if (sub != NULL && !is_alive->do_object_b(sub)) { 406 // first subklass not alive, find first one alive 407 do { 408 #ifndef PRODUCT 409 if (TraceClassUnloading && WizardMode) { 410 ResourceMark rm; 411 tty->print_cr("[Unlinking class (subclass) %s]", sub->klass_part()->external_name()); 412 } 413 #endif 414 sub = sub->klass_part()->next_sibling_oop(); 415 } while (sub != NULL && !is_alive->do_object_b(sub)); 416 set_subklass(sub); 417 } 418 // now update the subklass' sibling list 419 while (sub != NULL) { 420 klassOop next = sub->klass_part()->next_sibling_oop(); 421 if (next != NULL && !is_alive->do_object_b(next)) { 422 // first sibling not alive, find first one alive 423 do { 424 #ifndef PRODUCT 425 if (TraceClassUnloading && WizardMode) { 426 ResourceMark rm; 427 tty->print_cr("[Unlinking class (sibling) %s]", next->klass_part()->external_name()); 428 } 429 #endif 430 next = next->klass_part()->next_sibling_oop(); 431 } while (next != NULL && !is_alive->do_object_b(next)); 432 sub->klass_part()->set_next_sibling(next); 433 } 434 sub = next; 435 } 436 } else { 437 // Always follow subklass and sibling link. This will prevent any klasses from 438 // being unloaded (all classes are transitively linked from java.lang.Object). 439 keep_alive->do_oop(adr_subklass()); 440 keep_alive->do_oop(adr_next_sibling()); 441 } 442 } 443 444 445 void Klass::remove_unshareable_info() { 446 if (oop_is_instance()) { 447 instanceKlass* ik = (instanceKlass*)this; 448 if (ik->is_linked()) { 449 ik->unlink_class(); 450 } 451 } 452 set_subklass(NULL); 453 set_next_sibling(NULL); 454 } 455 456 457 klassOop Klass::array_klass_or_null(int rank) { 458 EXCEPTION_MARK; 459 // No exception can be thrown by array_klass_impl when called with or_null == true. 460 // (In anycase, the execption mark will fail if it do so) 461 return array_klass_impl(true, rank, THREAD); 462 } 463 464 465 klassOop Klass::array_klass_or_null() { 466 EXCEPTION_MARK; 467 // No exception can be thrown by array_klass_impl when called with or_null == true. 468 // (In anycase, the execption mark will fail if it do so) 469 return array_klass_impl(true, THREAD); 470 } 471 472 473 klassOop Klass::array_klass_impl(bool or_null, int rank, TRAPS) { 474 fatal("array_klass should be dispatched to instanceKlass, objArrayKlass or typeArrayKlass"); 475 return NULL; 476 } 477 478 479 klassOop Klass::array_klass_impl(bool or_null, TRAPS) { 480 fatal("array_klass should be dispatched to instanceKlass, objArrayKlass or typeArrayKlass"); 481 return NULL; 482 } 483 484 485 void Klass::with_array_klasses_do(void f(klassOop k)) { 486 f(as_klassOop()); 487 } 488 489 490 const char* Klass::external_name() const { 491 if (oop_is_instance()) { 492 instanceKlass* ik = (instanceKlass*) this; 493 if (ik->is_anonymous()) { 494 assert(AnonymousClasses, ""); 495 intptr_t hash = ik->java_mirror()->identity_hash(); 496 char hash_buf[40]; 497 sprintf(hash_buf, "/" UINTX_FORMAT, (uintx)hash); 498 size_t hash_len = strlen(hash_buf); 499 500 size_t result_len = name()->utf8_length(); 501 char* result = NEW_RESOURCE_ARRAY(char, result_len + hash_len + 1); 502 name()->as_klass_external_name(result, (int) result_len + 1); 503 assert(strlen(result) == result_len, ""); 504 strcpy(result + result_len, hash_buf); 505 assert(strlen(result) == result_len + hash_len, ""); 506 return result; 507 } 508 } 509 if (name() == NULL) return "<unknown>"; 510 return name()->as_klass_external_name(); 511 } 512 513 514 const char* Klass::signature_name() const { 515 if (name() == NULL) return "<unknown>"; 516 return name()->as_C_string(); 517 } 518 519 // Unless overridden, modifier_flags is 0. 520 jint Klass::compute_modifier_flags(TRAPS) const { 521 return 0; 522 } 523 524 int Klass::atomic_incr_biased_lock_revocation_count() { 525 return (int) Atomic::add(1, &_biased_lock_revocation_count); 526 } 527 528 // Unless overridden, jvmti_class_status has no flags set. 529 jint Klass::jvmti_class_status() const { 530 return 0; 531 } 532 533 // Printing 534 535 void Klass::oop_print_on(oop obj, outputStream* st) { 536 ResourceMark rm; 537 // print title 538 st->print_cr("%s ", internal_name()); 539 obj->print_address_on(st); 540 541 if (WizardMode) { 542 // print header 543 obj->mark()->print_on(st); 544 } 545 546 // print class 547 st->print(" - klass: "); 548 obj->klass()->print_value_on(st); 549 st->cr(); 550 } 551 552 void Klass::oop_print_value_on(oop obj, outputStream* st) { 553 // print title 554 ResourceMark rm; // Cannot print in debug mode without this 555 st->print("%s", internal_name()); 556 obj->print_address_on(st); 557 } 558 559 // Verification 560 561 void Klass::oop_verify_on(oop obj, outputStream* st) { 562 guarantee(obj->is_oop(), "should be oop"); 563 guarantee(obj->klass()->is_perm(), "should be in permspace"); 564 guarantee(obj->klass()->is_klass(), "klass field is not a klass"); 565 } 566 567 568 void Klass::oop_verify_old_oop(oop obj, oop* p, bool allow_dirty) { 569 /* $$$ I think this functionality should be handled by verification of 570 RememberedSet::verify_old_oop(obj, p, allow_dirty, false); 571 the card table. */ 572 } 573 void Klass::oop_verify_old_oop(oop obj, narrowOop* p, bool allow_dirty) { } 574 575 #ifndef PRODUCT 576 577 void Klass::verify_vtable_index(int i) { 578 assert(oop_is_instance() || oop_is_array(), "only instanceKlass and arrayKlass have vtables"); 579 if (oop_is_instance()) { 580 assert(i>=0 && i<((instanceKlass*)this)->vtable_length()/vtableEntry::size(), "index out of bounds"); 581 } else { 582 assert(i>=0 && i<((arrayKlass*)this)->vtable_length()/vtableEntry::size(), "index out of bounds"); 583 } 584 } 585 586 #endif