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 void Klass::set_name(Symbol* n) {
39 _name = n;
40 if (_name != NULL) _name->increment_refcount();
41 }
42
43 bool Klass::is_subclass_of(klassOop k) const {
44 // Run up the super chain and check
45 klassOop t = as_klassOop();
46
47 if (t == k) return true;
48 t = Klass::cast(t)->super();
49
50 while (t != NULL) {
51 if (t == k) return true;
52 t = Klass::cast(t)->super();
53 }
54 return false;
55 }
56
57 bool Klass::search_secondary_supers(klassOop k) const {
58 // Put some extra logic here out-of-line, before the search proper.
59 // This cuts down the size of the inline method.
60
61 // This is necessary, since I am never in my own secondary_super list.
62 if (this->as_klassOop() == k)
63 return true;
64 // Scan the array-of-objects for a match
65 int cnt = secondary_supers()->length();
66 for (int i = 0; i < cnt; i++) {
67 if (secondary_supers()->obj_at(i) == k) {
68 ((Klass*)this)->set_secondary_super_cache(k);
69 return true;
70 }
71 }
72 return false;
73 }
74
75 // Return self, except for abstract classes with exactly 1
76 // implementor. Then return the 1 concrete implementation.
77 Klass *Klass::up_cast_abstract() {
78 Klass *r = this;
79 while( r->is_abstract() ) { // Receiver is abstract?
80 Klass *s = r->subklass(); // Check for exactly 1 subklass
81 if( !s || s->next_sibling() ) // Oops; wrong count; give up
82 return this; // Return 'this' as a no-progress flag
83 r = s; // Loop till find concrete class
84 }
85 return r; // Return the 1 concrete class
86 }
87
88 // Find LCA in class hierarchy
89 Klass *Klass::LCA( Klass *k2 ) {
90 Klass *k1 = this;
91 while( 1 ) {
92 if( k1->is_subtype_of(k2->as_klassOop()) ) return k2;
93 if( k2->is_subtype_of(k1->as_klassOop()) ) return k1;
94 k1 = k1->super()->klass_part();
95 k2 = k2->super()->klass_part();
96 }
97 }
98
99
100 void Klass::check_valid_for_instantiation(bool throwError, TRAPS) {
101 ResourceMark rm(THREAD);
102 THROW_MSG(throwError ? vmSymbols::java_lang_InstantiationError()
103 : vmSymbols::java_lang_InstantiationException(), external_name());
104 }
105
106
107 void Klass::copy_array(arrayOop s, int src_pos, arrayOop d, int dst_pos, int length, TRAPS) {
108 THROW(vmSymbols::java_lang_ArrayStoreException());
109 }
110
111
112 void Klass::initialize(TRAPS) {
113 ShouldNotReachHere();
114 }
115
116 bool Klass::compute_is_subtype_of(klassOop k) {
117 assert(k->is_klass(), "argument must be a class");
118 return is_subclass_of(k);
119 }
120
121
122 methodOop Klass::uncached_lookup_method(Symbol* name, Symbol* signature) const {
123 #ifdef ASSERT
124 tty->print_cr("Error: uncached_lookup_method called on a klass oop."
125 " Likely error: reflection method does not correctly"
126 " wrap return value in a mirror object.");
127 #endif
128 ShouldNotReachHere();
129 return NULL;
130 }
131
132 klassOop Klass::base_create_klass_oop(KlassHandle& klass, int size,
133 const Klass_vtbl& vtbl, TRAPS) {
134 size = align_object_size(size);
135 // allocate and initialize vtable
136 Klass* kl = (Klass*) vtbl.allocate_permanent(klass, size, CHECK_NULL);
137 klassOop k = kl->as_klassOop();
138
139 { // Preinitialize supertype information.
140 // A later call to initialize_supers() may update these settings:
141 kl->set_super(NULL);
142 for (juint i = 0; i < Klass::primary_super_limit(); i++) {
143 kl->_primary_supers[i] = NULL;
144 }
145 kl->set_secondary_supers(NULL);
146 oop_store_without_check((oop*) &kl->_primary_supers[0], k);
147 kl->set_super_check_offset(primary_supers_offset_in_bytes() + sizeof(oopDesc));
148 }
149
150 kl->set_java_mirror(NULL);
151 kl->set_modifier_flags(0);
152 kl->set_layout_helper(Klass::_lh_neutral_value);
153 kl->set_name(NULL);
154 AccessFlags af;
155 af.set_flags(0);
156 kl->set_access_flags(af);
157 kl->set_subklass(NULL);
158 kl->set_next_sibling(NULL);
159 kl->set_alloc_count(0);
160 kl->set_alloc_size(0);
161
162 kl->set_prototype_header(markOopDesc::prototype());
163 kl->set_biased_lock_revocation_count(0);
164 kl->set_last_biased_lock_bulk_revocation_time(0);
165
166 return k;
167 }
168
169 KlassHandle Klass::base_create_klass(KlassHandle& klass, int size,
170 const Klass_vtbl& vtbl, TRAPS) {
171 klassOop ek = base_create_klass_oop(klass, size, vtbl, THREAD);
172 return KlassHandle(THREAD, ek);
173 }
174
175 void Klass_vtbl::post_new_init_klass(KlassHandle& klass,
176 klassOop new_klass,
177 int size) const {
178 assert(!new_klass->klass_part()->null_vtbl(), "Not a complete klass");
179 CollectedHeap::post_allocation_install_obj_klass(klass, new_klass, size);
180 }
181
182 void* Klass_vtbl::operator new(size_t ignored, KlassHandle& klass,
183 int size, TRAPS) {
184 // The vtable pointer is installed during the execution of
185 // constructors in the call to permanent_obj_allocate(). Delay
186 // the installation of the klass pointer into the new klass "k"
187 // until after the vtable pointer has been installed (i.e., until
188 // after the return of permanent_obj_allocate().
189 klassOop k =
190 (klassOop) CollectedHeap::permanent_obj_allocate_no_klass_install(klass,
191 size, CHECK_NULL);
192 return k->klass_part();
193 }
194
195 jint Klass::array_layout_helper(BasicType etype) {
196 assert(etype >= T_BOOLEAN && etype <= T_OBJECT, "valid etype");
197 // Note that T_ARRAY is not allowed here.
198 int hsize = arrayOopDesc::base_offset_in_bytes(etype);
199 int esize = type2aelembytes(etype);
200 bool isobj = (etype == T_OBJECT);
201 int tag = isobj ? _lh_array_tag_obj_value : _lh_array_tag_type_value;
202 int lh = array_layout_helper(tag, hsize, etype, exact_log2(esize));
203
204 assert(lh < (int)_lh_neutral_value, "must look like an array layout");
205 assert(layout_helper_is_javaArray(lh), "correct kind");
206 assert(layout_helper_is_objArray(lh) == isobj, "correct kind");
207 assert(layout_helper_is_typeArray(lh) == !isobj, "correct kind");
208 assert(layout_helper_header_size(lh) == hsize, "correct decode");
209 assert(layout_helper_element_type(lh) == etype, "correct decode");
210 assert(1 << layout_helper_log2_element_size(lh) == esize, "correct decode");
211
212 return lh;
213 }
214
215 bool Klass::can_be_primary_super_slow() const {
216 if (super() == NULL)
217 return true;
218 else if (super()->klass_part()->super_depth() >= primary_super_limit()-1)
219 return false;
220 else
221 return true;
222 }
223
224 void Klass::initialize_supers(klassOop k, TRAPS) {
225 if (FastSuperclassLimit == 0) {
226 // None of the other machinery matters.
227 set_super(k);
228 return;
229 }
230 if (k == NULL) {
231 set_super(NULL);
232 oop_store_without_check((oop*) &_primary_supers[0], (oop) this->as_klassOop());
233 assert(super_depth() == 0, "Object must already be initialized properly");
234 } else if (k != super() || k == SystemDictionary::Object_klass()) {
235 assert(super() == NULL || super() == SystemDictionary::Object_klass(),
236 "initialize this only once to a non-trivial value");
237 set_super(k);
238 Klass* sup = k->klass_part();
239 int sup_depth = sup->super_depth();
240 juint my_depth = MIN2(sup_depth + 1, (int)primary_super_limit());
241 if (!can_be_primary_super_slow())
242 my_depth = primary_super_limit();
243 for (juint i = 0; i < my_depth; i++) {
244 oop_store_without_check((oop*) &_primary_supers[i], (oop) sup->_primary_supers[i]);
245 }
246 klassOop *super_check_cell;
247 if (my_depth < primary_super_limit()) {
248 oop_store_without_check((oop*) &_primary_supers[my_depth], (oop) this->as_klassOop());
249 super_check_cell = &_primary_supers[my_depth];
250 } else {
251 // Overflow of the primary_supers array forces me to be secondary.
252 super_check_cell = &_secondary_super_cache;
253 }
254 set_super_check_offset((address)super_check_cell - (address) this->as_klassOop());
255
256 #ifdef ASSERT
257 {
258 juint j = super_depth();
259 assert(j == my_depth, "computed accessor gets right answer");
260 klassOop t = as_klassOop();
261 while (!Klass::cast(t)->can_be_primary_super()) {
262 t = Klass::cast(t)->super();
263 j = Klass::cast(t)->super_depth();
264 }
265 for (juint j1 = j+1; j1 < primary_super_limit(); j1++) {
266 assert(primary_super_of_depth(j1) == NULL, "super list padding");
267 }
268 while (t != NULL) {
269 assert(primary_super_of_depth(j) == t, "super list initialization");
270 t = Klass::cast(t)->super();
271 --j;
272 }
273 assert(j == (juint)-1, "correct depth count");
274 }
275 #endif
276 }
277
278 if (secondary_supers() == NULL) {
279 KlassHandle this_kh (THREAD, this);
280
281 // Now compute the list of secondary supertypes.
282 // Secondaries can occasionally be on the super chain,
283 // if the inline "_primary_supers" array overflows.
284 int extras = 0;
285 klassOop p;
286 for (p = super(); !(p == NULL || p->klass_part()->can_be_primary_super()); p = p->klass_part()->super()) {
287 ++extras;
288 }
289
290 // Compute the "real" non-extra secondaries.
291 objArrayOop secondary_oops = compute_secondary_supers(extras, CHECK);
292 objArrayHandle secondaries (THREAD, secondary_oops);
293
294 // Store the extra secondaries in the first array positions:
295 int fillp = extras;
296 for (p = this_kh->super(); !(p == NULL || p->klass_part()->can_be_primary_super()); p = p->klass_part()->super()) {
297 int i; // Scan for overflow primaries being duplicates of 2nd'arys
298
299 // This happens frequently for very deeply nested arrays: the
300 // primary superclass chain overflows into the secondary. The
301 // secondary list contains the element_klass's secondaries with
302 // an extra array dimension added. If the element_klass's
303 // secondary list already contains some primary overflows, they
304 // (with the extra level of array-ness) will collide with the
305 // normal primary superclass overflows.
306 for( i = extras; i < secondaries->length(); i++ )
307 if( secondaries->obj_at(i) == p )
308 break;
309 if( i < secondaries->length() )
310 continue; // It's a dup, don't put it in
311 secondaries->obj_at_put(--fillp, p);
312 }
313 // See if we had some dup's, so the array has holes in it.
314 if( fillp > 0 ) {
315 // Pack the array. Drop the old secondaries array on the floor
316 // and let GC reclaim it.
317 objArrayOop s2 = oopFactory::new_system_objArray(secondaries->length() - fillp, CHECK);
318 for( int i = 0; i < s2->length(); i++ )
319 s2->obj_at_put( i, secondaries->obj_at(i+fillp) );
320 secondaries = objArrayHandle(THREAD, s2);
321 }
322
323 #ifdef ASSERT
324 if (secondaries() != Universe::the_array_interfaces_array()) {
325 // We must not copy any NULL placeholders left over from bootstrap.
326 for (int j = 0; j < secondaries->length(); j++) {
327 assert(secondaries->obj_at(j) != NULL, "correct bootstrapping order");
328 }
329 }
330 #endif
331
332 this_kh->set_secondary_supers(secondaries());
333 }
334 }
335
336 objArrayOop Klass::compute_secondary_supers(int num_extra_slots, TRAPS) {
337 assert(num_extra_slots == 0, "override for complex klasses");
338 return Universe::the_empty_system_obj_array();
339 }
340
341
342 Klass* Klass::subklass() const {
343 return _subklass == NULL ? NULL : Klass::cast(_subklass);
344 }
345
346 instanceKlass* Klass::superklass() const {
347 assert(super() == NULL || super()->klass_part()->oop_is_instance(), "must be instance klass");
348 return _super == NULL ? NULL : instanceKlass::cast(_super);
349 }
350
351 Klass* Klass::next_sibling() const {
352 return _next_sibling == NULL ? NULL : Klass::cast(_next_sibling);
353 }
354
355 void Klass::set_subklass(klassOop s) {
356 assert(s != as_klassOop(), "sanity check");
357 oop_store_without_check((oop*)&_subklass, s);
358 }
359
360 void Klass::set_next_sibling(klassOop s) {
361 assert(s != as_klassOop(), "sanity check");
362 oop_store_without_check((oop*)&_next_sibling, s);
363 }
364
365 void Klass::append_to_sibling_list() {
366 debug_only(if (!SharedSkipVerify) as_klassOop()->verify();)
367 // add ourselves to superklass' subklass list
368 instanceKlass* super = superklass();
369 if (super == NULL) return; // special case: class Object
370 assert(SharedSkipVerify ||
371 (!super->is_interface() // interfaces cannot be supers
372 && (super->superklass() == NULL || !is_interface())),
373 "an interface can only be a subklass of Object");
374 klassOop prev_first_subklass = super->subklass_oop();
375 if (prev_first_subklass != NULL) {
376 // set our sibling to be the superklass' previous first subklass
377 set_next_sibling(prev_first_subklass);
378 }
379 // make ourselves the superklass' first subklass
380 super->set_subklass(as_klassOop());
381 debug_only(if (!SharedSkipVerify) as_klassOop()->verify();)
382 }
383
384 void Klass::remove_from_sibling_list() {
385 // remove receiver from sibling list
386 instanceKlass* super = superklass();
387 assert(super != NULL || as_klassOop() == SystemDictionary::Object_klass(), "should have super");
388 if (super == NULL) return; // special case: class Object
389 if (super->subklass() == this) {
390 // first subklass
391 super->set_subklass(_next_sibling);
392 } else {
393 Klass* sib = super->subklass();
394 while (sib->next_sibling() != this) {
395 sib = sib->next_sibling();
396 };
397 sib->set_next_sibling(_next_sibling);
398 }
399 }
400
401 void Klass::follow_weak_klass_links( BoolObjectClosure* is_alive, OopClosure* keep_alive) {
402 // This klass is alive but the subklass and siblings are not followed/updated.
403 // We update the subklass link and the subklass' sibling links here.
404 // Our own sibling link will be updated by our superclass (which must be alive
405 // since we are).
406 assert(is_alive->do_object_b(as_klassOop()), "just checking, this should be live");
407 if (ClassUnloading) {
408 klassOop sub = subklass_oop();
409 if (sub != NULL && !is_alive->do_object_b(sub)) {
410 // first subklass not alive, find first one alive
411 do {
412 #ifndef PRODUCT
413 if (TraceClassUnloading && WizardMode) {
414 ResourceMark rm;
415 tty->print_cr("[Unlinking class (subclass) %s]", sub->klass_part()->external_name());
416 }
417 #endif
418 sub = sub->klass_part()->next_sibling_oop();
419 } while (sub != NULL && !is_alive->do_object_b(sub));
420 set_subklass(sub);
421 }
422 // now update the subklass' sibling list
423 while (sub != NULL) {
424 klassOop next = sub->klass_part()->next_sibling_oop();
425 if (next != NULL && !is_alive->do_object_b(next)) {
426 // first sibling not alive, find first one alive
427 do {
428 #ifndef PRODUCT
429 if (TraceClassUnloading && WizardMode) {
430 ResourceMark rm;
431 tty->print_cr("[Unlinking class (sibling) %s]", next->klass_part()->external_name());
432 }
433 #endif
434 next = next->klass_part()->next_sibling_oop();
435 } while (next != NULL && !is_alive->do_object_b(next));
436 sub->klass_part()->set_next_sibling(next);
437 }
438 sub = next;
439 }
440 } else {
441 // Always follow subklass and sibling link. This will prevent any klasses from
442 // being unloaded (all classes are transitively linked from java.lang.Object).
443 keep_alive->do_oop(adr_subklass());
444 keep_alive->do_oop(adr_next_sibling());
445 }
446 }
447
448
449 void Klass::remove_unshareable_info() {
450 if (oop_is_instance()) {
451 instanceKlass* ik = (instanceKlass*)this;
452 if (ik->is_linked()) {
453 ik->unlink_class();
454 }
455 }
456 set_subklass(NULL);
457 set_next_sibling(NULL);
458 }
459
460
461 void Klass::shared_symbols_iterate(SymbolClosure* closure) {
462 closure->do_symbol(&_name);
463 }
464
465
466 klassOop Klass::array_klass_or_null(int rank) {
467 EXCEPTION_MARK;
468 // No exception can be thrown by array_klass_impl when called with or_null == true.
469 // (In anycase, the execption mark will fail if it do so)
470 return array_klass_impl(true, rank, THREAD);
471 }
472
473
474 klassOop Klass::array_klass_or_null() {
475 EXCEPTION_MARK;
476 // No exception can be thrown by array_klass_impl when called with or_null == true.
477 // (In anycase, the execption mark will fail if it do so)
478 return array_klass_impl(true, THREAD);
479 }
480
481
482 klassOop Klass::array_klass_impl(bool or_null, int rank, TRAPS) {
483 fatal("array_klass should be dispatched to instanceKlass, objArrayKlass or typeArrayKlass");
484 return NULL;
485 }
486
487
488 klassOop Klass::array_klass_impl(bool or_null, TRAPS) {
489 fatal("array_klass should be dispatched to instanceKlass, objArrayKlass or typeArrayKlass");
490 return NULL;
491 }
492
493
494 void Klass::with_array_klasses_do(void f(klassOop k)) {
495 f(as_klassOop());
496 }
497
498
499 const char* Klass::external_name() const {
500 if (oop_is_instance()) {
501 instanceKlass* ik = (instanceKlass*) this;
502 if (ik->is_anonymous()) {
503 assert(EnableInvokeDynamic, "");
504 intptr_t hash = ik->java_mirror()->identity_hash();
505 char hash_buf[40];
506 sprintf(hash_buf, "/" UINTX_FORMAT, (uintx)hash);
507 size_t hash_len = strlen(hash_buf);
508
509 size_t result_len = name()->utf8_length();
510 char* result = NEW_RESOURCE_ARRAY(char, result_len + hash_len + 1);
511 name()->as_klass_external_name(result, (int) result_len + 1);
512 assert(strlen(result) == result_len, "");
513 strcpy(result + result_len, hash_buf);
514 assert(strlen(result) == result_len + hash_len, "");
515 return result;
516 }
517 }
518 if (name() == NULL) return "<unknown>";
519 return name()->as_klass_external_name();
520 }
521
522
523 const char* Klass::signature_name() const {
524 if (name() == NULL) return "<unknown>";
525 return name()->as_C_string();
526 }
527
528 // Unless overridden, modifier_flags is 0.
529 jint Klass::compute_modifier_flags(TRAPS) const {
530 return 0;
531 }
532
533 int Klass::atomic_incr_biased_lock_revocation_count() {
534 return (int) Atomic::add(1, &_biased_lock_revocation_count);
535 }
536
537 // Unless overridden, jvmti_class_status has no flags set.
538 jint Klass::jvmti_class_status() const {
539 return 0;
540 }
541
542 // Printing
543
544 void Klass::oop_print_on(oop obj, outputStream* st) {
545 ResourceMark rm;
546 // print title
547 st->print_cr("%s ", internal_name());
548 obj->print_address_on(st);
549
550 if (WizardMode) {
551 // print header
552 obj->mark()->print_on(st);
553 }
554
555 // print class
556 st->print(" - klass: ");
557 obj->klass()->print_value_on(st);
558 st->cr();
559 }
560
561 void Klass::oop_print_value_on(oop obj, outputStream* st) {
562 // print title
563 ResourceMark rm; // Cannot print in debug mode without this
564 st->print("%s", internal_name());
565 obj->print_address_on(st);
566 }
567
568 // Verification
569
570 void Klass::oop_verify_on(oop obj, outputStream* st) {
571 guarantee(obj->is_oop(), "should be oop");
572 guarantee(obj->klass()->is_perm(), "should be in permspace");
573 guarantee(obj->klass()->is_klass(), "klass field is not a klass");
574 }
575
576
577 void Klass::oop_verify_old_oop(oop obj, oop* p, bool allow_dirty) {
578 /* $$$ I think this functionality should be handled by verification of
579 RememberedSet::verify_old_oop(obj, p, allow_dirty, false);
580 the card table. */
581 }
582 void Klass::oop_verify_old_oop(oop obj, narrowOop* p, bool allow_dirty) { }
583
584 #ifndef PRODUCT
585
586 void Klass::verify_vtable_index(int i) {
587 assert(oop_is_instance() || oop_is_array(), "only instanceKlass and arrayKlass have vtables");
588 if (oop_is_instance()) {
589 assert(i>=0 && i<((instanceKlass*)this)->vtable_length()/vtableEntry::size(), "index out of bounds");
590 } else {
591 assert(i>=0 && i<((arrayKlass*)this)->vtable_length()/vtableEntry::size(), "index out of bounds");
592 }
593 }
594
595 #endif