1 /*
2 * Copyright (c) 1997, 2008, 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 "incls/_precompiled.incl"
26 # include "incls/_klass.cpp.incl"
27
28
29 bool Klass::is_subclass_of(klassOop k) const {
30 // Run up the super chain and check
31 klassOop t = as_klassOop();
32
33 if (t == k) return true;
34 t = Klass::cast(t)->super();
35
36 while (t != NULL) {
37 if (t == k) return true;
38 t = Klass::cast(t)->super();
39 }
40 return false;
41 }
42
43 bool Klass::search_secondary_supers(klassOop k) const {
44 // Put some extra logic here out-of-line, before the search proper.
45 // This cuts down the size of the inline method.
46
47 // This is necessary, since I am never in my own secondary_super list.
48 if (this->as_klassOop() == k)
49 return true;
50 // Scan the array-of-objects for a match
51 int cnt = secondary_supers()->length();
52 for (int i = 0; i < cnt; i++) {
53 if (secondary_supers()->obj_at(i) == k) {
54 ((Klass*)this)->set_secondary_super_cache(k);
55 return true;
56 }
57 }
58 return false;
59 }
60
61 // Return self, except for abstract classes with exactly 1
62 // implementor. Then return the 1 concrete implementation.
63 Klass *Klass::up_cast_abstract() {
64 Klass *r = this;
65 while( r->is_abstract() ) { // Receiver is abstract?
66 Klass *s = r->subklass(); // Check for exactly 1 subklass
67 if( !s || s->next_sibling() ) // Oops; wrong count; give up
68 return this; // Return 'this' as a no-progress flag
69 r = s; // Loop till find concrete class
70 }
71 return r; // Return the 1 concrete class
72 }
73
74 // Find LCA in class hierarchy
75 Klass *Klass::LCA( Klass *k2 ) {
76 Klass *k1 = this;
77 while( 1 ) {
78 if( k1->is_subtype_of(k2->as_klassOop()) ) return k2;
79 if( k2->is_subtype_of(k1->as_klassOop()) ) return k1;
80 k1 = k1->super()->klass_part();
81 k2 = k2->super()->klass_part();
82 }
83 }
84
85
86 void Klass::check_valid_for_instantiation(bool throwError, TRAPS) {
87 ResourceMark rm(THREAD);
88 THROW_MSG(throwError ? vmSymbols::java_lang_InstantiationError()
89 : vmSymbols::java_lang_InstantiationException(), external_name());
90 }
91
92
93 void Klass::copy_array(arrayOop s, int src_pos, arrayOop d, int dst_pos, int length, TRAPS) {
94 THROW(vmSymbols::java_lang_ArrayStoreException());
95 }
96
97
98 void Klass::initialize(TRAPS) {
99 ShouldNotReachHere();
100 }
101
102 bool Klass::compute_is_subtype_of(klassOop k) {
103 assert(k->is_klass(), "argument must be a class");
104 return is_subclass_of(k);
105 }
106
107
108 methodOop Klass::uncached_lookup_method(symbolOop name, symbolOop signature) const {
109 #ifdef ASSERT
110 tty->print_cr("Error: uncached_lookup_method called on a klass oop."
111 " Likely error: reflection method does not correctly"
112 " wrap return value in a mirror object.");
113 #endif
114 ShouldNotReachHere();
115 return NULL;
116 }
117
118 klassOop Klass::base_create_klass_oop(KlassHandle& klass, int size,
119 const Klass_vtbl& vtbl, TRAPS) {
120 size = align_object_size(size);
121 // allocate and initialize vtable
122 Klass* kl = (Klass*) vtbl.allocate_permanent(klass, size, CHECK_NULL);
123 klassOop k = kl->as_klassOop();
124
125 { // Preinitialize supertype information.
126 // A later call to initialize_supers() may update these settings:
127 kl->set_super(NULL);
128 for (juint i = 0; i < Klass::primary_super_limit(); i++) {
129 kl->_primary_supers[i] = NULL;
130 }
131 kl->set_secondary_supers(NULL);
132 oop_store_without_check((oop*) &kl->_primary_supers[0], k);
133 kl->set_super_check_offset(primary_supers_offset_in_bytes() + sizeof(oopDesc));
134 }
135
136 kl->set_java_mirror(NULL);
137 kl->set_modifier_flags(0);
138 kl->set_layout_helper(Klass::_lh_neutral_value);
139 kl->set_name(NULL);
140 AccessFlags af;
141 af.set_flags(0);
142 kl->set_access_flags(af);
143 kl->set_subklass(NULL);
144 kl->set_next_sibling(NULL);
145 kl->set_alloc_count(0);
146 kl->set_alloc_size(0);
147
148 kl->set_prototype_header(markOopDesc::prototype());
149 kl->set_biased_lock_revocation_count(0);
150 kl->set_last_biased_lock_bulk_revocation_time(0);
151
152 return k;
153 }
154
155 KlassHandle Klass::base_create_klass(KlassHandle& klass, int size,
156 const Klass_vtbl& vtbl, TRAPS) {
157 klassOop ek = base_create_klass_oop(klass, size, vtbl, THREAD);
158 return KlassHandle(THREAD, ek);
159 }
160
161 void Klass_vtbl::post_new_init_klass(KlassHandle& klass,
162 klassOop new_klass,
163 int size) const {
164 assert(!new_klass->klass_part()->null_vtbl(), "Not a complete klass");
165 CollectedHeap::post_allocation_install_obj_klass(klass, new_klass, size);
166 }
167
168 void* Klass_vtbl::operator new(size_t ignored, KlassHandle& klass,
169 int size, TRAPS) {
170 // The vtable pointer is installed during the execution of
171 // constructors in the call to permanent_obj_allocate(). Delay
172 // the installation of the klass pointer into the new klass "k"
173 // until after the vtable pointer has been installed (i.e., until
174 // after the return of permanent_obj_allocate().
175 klassOop k =
176 (klassOop) CollectedHeap::permanent_obj_allocate_no_klass_install(klass,
177 size, CHECK_NULL);
178 return k->klass_part();
179 }
180
181 jint Klass::array_layout_helper(BasicType etype) {
182 assert(etype >= T_BOOLEAN && etype <= T_OBJECT, "valid etype");
183 // Note that T_ARRAY is not allowed here.
184 int hsize = arrayOopDesc::base_offset_in_bytes(etype);
185 int esize = type2aelembytes(etype);
186 bool isobj = (etype == T_OBJECT);
187 int tag = isobj ? _lh_array_tag_obj_value : _lh_array_tag_type_value;
188 int lh = array_layout_helper(tag, hsize, etype, exact_log2(esize));
189
190 assert(lh < (int)_lh_neutral_value, "must look like an array layout");
191 assert(layout_helper_is_javaArray(lh), "correct kind");
192 assert(layout_helper_is_objArray(lh) == isobj, "correct kind");
193 assert(layout_helper_is_typeArray(lh) == !isobj, "correct kind");
194 assert(layout_helper_header_size(lh) == hsize, "correct decode");
195 assert(layout_helper_element_type(lh) == etype, "correct decode");
196 assert(1 << layout_helper_log2_element_size(lh) == esize, "correct decode");
197
198 return lh;
199 }
200
201 bool Klass::can_be_primary_super_slow() const {
202 if (super() == NULL)
203 return true;
204 else if (super()->klass_part()->super_depth() >= primary_super_limit()-1)
205 return false;
206 else
207 return true;
208 }
209
210 void Klass::initialize_supers(klassOop k, TRAPS) {
211 if (FastSuperclassLimit == 0) {
212 // None of the other machinery matters.
213 set_super(k);
214 return;
215 }
216 if (k == NULL) {
217 set_super(NULL);
218 oop_store_without_check((oop*) &_primary_supers[0], (oop) this->as_klassOop());
219 assert(super_depth() == 0, "Object must already be initialized properly");
220 } else if (k != super() || k == SystemDictionary::Object_klass()) {
221 assert(super() == NULL || super() == SystemDictionary::Object_klass(),
222 "initialize this only once to a non-trivial value");
223 set_super(k);
224 Klass* sup = k->klass_part();
225 int sup_depth = sup->super_depth();
226 juint my_depth = MIN2(sup_depth + 1, (int)primary_super_limit());
227 if (!can_be_primary_super_slow())
228 my_depth = primary_super_limit();
229 for (juint i = 0; i < my_depth; i++) {
230 oop_store_without_check((oop*) &_primary_supers[i], (oop) sup->_primary_supers[i]);
231 }
232 klassOop *super_check_cell;
233 if (my_depth < primary_super_limit()) {
234 oop_store_without_check((oop*) &_primary_supers[my_depth], (oop) this->as_klassOop());
235 super_check_cell = &_primary_supers[my_depth];
236 } else {
237 // Overflow of the primary_supers array forces me to be secondary.
238 super_check_cell = &_secondary_super_cache;
239 }
240 set_super_check_offset((address)super_check_cell - (address) this->as_klassOop());
241
242 #ifdef ASSERT
243 {
244 juint j = super_depth();
245 assert(j == my_depth, "computed accessor gets right answer");
246 klassOop t = as_klassOop();
247 while (!Klass::cast(t)->can_be_primary_super()) {
248 t = Klass::cast(t)->super();
249 j = Klass::cast(t)->super_depth();
250 }
251 for (juint j1 = j+1; j1 < primary_super_limit(); j1++) {
252 assert(primary_super_of_depth(j1) == NULL, "super list padding");
253 }
254 while (t != NULL) {
255 assert(primary_super_of_depth(j) == t, "super list initialization");
256 t = Klass::cast(t)->super();
257 --j;
258 }
259 assert(j == (juint)-1, "correct depth count");
260 }
261 #endif
262 }
263
264 if (secondary_supers() == NULL) {
265 KlassHandle this_kh (THREAD, this);
266
267 // Now compute the list of secondary supertypes.
268 // Secondaries can occasionally be on the super chain,
269 // if the inline "_primary_supers" array overflows.
270 int extras = 0;
271 klassOop p;
272 for (p = super(); !(p == NULL || p->klass_part()->can_be_primary_super()); p = p->klass_part()->super()) {
273 ++extras;
274 }
275
276 // Compute the "real" non-extra secondaries.
277 objArrayOop secondary_oops = compute_secondary_supers(extras, CHECK);
278 objArrayHandle secondaries (THREAD, secondary_oops);
279
280 // Store the extra secondaries in the first array positions:
281 int fillp = extras;
282 for (p = this_kh->super(); !(p == NULL || p->klass_part()->can_be_primary_super()); p = p->klass_part()->super()) {
283 int i; // Scan for overflow primaries being duplicates of 2nd'arys
284
285 // This happens frequently for very deeply nested arrays: the
286 // primary superclass chain overflows into the secondary. The
287 // secondary list contains the element_klass's secondaries with
288 // an extra array dimension added. If the element_klass's
289 // secondary list already contains some primary overflows, they
290 // (with the extra level of array-ness) will collide with the
291 // normal primary superclass overflows.
292 for( i = extras; i < secondaries->length(); i++ )
293 if( secondaries->obj_at(i) == p )
294 break;
295 if( i < secondaries->length() )
296 continue; // It's a dup, don't put it in
297 secondaries->obj_at_put(--fillp, p);
298 }
299 // See if we had some dup's, so the array has holes in it.
300 if( fillp > 0 ) {
301 // Pack the array. Drop the old secondaries array on the floor
302 // and let GC reclaim it.
303 objArrayOop s2 = oopFactory::new_system_objArray(secondaries->length() - fillp, CHECK);
304 for( int i = 0; i < s2->length(); i++ )
305 s2->obj_at_put( i, secondaries->obj_at(i+fillp) );
306 secondaries = objArrayHandle(THREAD, s2);
307 }
308
309 #ifdef ASSERT
310 if (secondaries() != Universe::the_array_interfaces_array()) {
311 // We must not copy any NULL placeholders left over from bootstrap.
312 for (int j = 0; j < secondaries->length(); j++) {
313 assert(secondaries->obj_at(j) != NULL, "correct bootstrapping order");
314 }
315 }
316 #endif
317
318 this_kh->set_secondary_supers(secondaries());
319 }
320 }
321
322 objArrayOop Klass::compute_secondary_supers(int num_extra_slots, TRAPS) {
323 assert(num_extra_slots == 0, "override for complex klasses");
324 return Universe::the_empty_system_obj_array();
325 }
326
327
328 Klass* Klass::subklass() const {
329 return _subklass == NULL ? NULL : Klass::cast(_subklass);
330 }
331
332 instanceKlass* Klass::superklass() const {
333 assert(super() == NULL || super()->klass_part()->oop_is_instance(), "must be instance klass");
334 return _super == NULL ? NULL : instanceKlass::cast(_super);
335 }
336
337 Klass* Klass::next_sibling() const {
338 return _next_sibling == NULL ? NULL : Klass::cast(_next_sibling);
339 }
340
341 void Klass::set_subklass(klassOop s) {
342 assert(s != as_klassOop(), "sanity check");
343 oop_store_without_check((oop*)&_subklass, s);
344 }
345
346 void Klass::set_next_sibling(klassOop s) {
347 assert(s != as_klassOop(), "sanity check");
348 oop_store_without_check((oop*)&_next_sibling, s);
349 }
350
351 void Klass::append_to_sibling_list() {
352 debug_only(if (!SharedSkipVerify) as_klassOop()->verify();)
353 // add ourselves to superklass' subklass list
354 instanceKlass* super = superklass();
355 if (super == NULL) return; // special case: class Object
356 assert(SharedSkipVerify ||
357 (!super->is_interface() // interfaces cannot be supers
358 && (super->superklass() == NULL || !is_interface())),
359 "an interface can only be a subklass of Object");
360 klassOop prev_first_subklass = super->subklass_oop();
361 if (prev_first_subklass != NULL) {
362 // set our sibling to be the superklass' previous first subklass
363 set_next_sibling(prev_first_subklass);
364 }
365 // make ourselves the superklass' first subklass
366 super->set_subklass(as_klassOop());
367 debug_only(if (!SharedSkipVerify) as_klassOop()->verify();)
368 }
369
370 void Klass::remove_from_sibling_list() {
371 // remove receiver from sibling list
372 instanceKlass* super = superklass();
373 assert(super != NULL || as_klassOop() == SystemDictionary::Object_klass(), "should have super");
374 if (super == NULL) return; // special case: class Object
375 if (super->subklass() == this) {
376 // first subklass
377 super->set_subklass(_next_sibling);
378 } else {
379 Klass* sib = super->subklass();
380 while (sib->next_sibling() != this) {
381 sib = sib->next_sibling();
382 };
383 sib->set_next_sibling(_next_sibling);
384 }
385 }
386
387 void Klass::follow_weak_klass_links( BoolObjectClosure* is_alive, OopClosure* keep_alive) {
388 // This klass is alive but the subklass and siblings are not followed/updated.
389 // We update the subklass link and the subklass' sibling links here.
390 // Our own sibling link will be updated by our superclass (which must be alive
391 // since we are).
392 assert(is_alive->do_object_b(as_klassOop()), "just checking, this should be live");
393 if (ClassUnloading) {
394 klassOop sub = subklass_oop();
395 if (sub != NULL && !is_alive->do_object_b(sub)) {
396 // first subklass not alive, find first one alive
397 do {
398 #ifndef PRODUCT
399 if (TraceClassUnloading && WizardMode) {
400 ResourceMark rm;
401 tty->print_cr("[Unlinking class (subclass) %s]", sub->klass_part()->external_name());
402 }
403 #endif
404 sub = sub->klass_part()->next_sibling_oop();
405 } while (sub != NULL && !is_alive->do_object_b(sub));
406 set_subklass(sub);
407 }
408 // now update the subklass' sibling list
409 while (sub != NULL) {
410 klassOop next = sub->klass_part()->next_sibling_oop();
411 if (next != NULL && !is_alive->do_object_b(next)) {
412 // first sibling not alive, find first one alive
413 do {
414 #ifndef PRODUCT
415 if (TraceClassUnloading && WizardMode) {
416 ResourceMark rm;
417 tty->print_cr("[Unlinking class (sibling) %s]", next->klass_part()->external_name());
418 }
419 #endif
420 next = next->klass_part()->next_sibling_oop();
421 } while (next != NULL && !is_alive->do_object_b(next));
422 sub->klass_part()->set_next_sibling(next);
423 }
424 sub = next;
425 }
426 } else {
427 // Always follow subklass and sibling link. This will prevent any klasses from
428 // being unloaded (all classes are transitively linked from java.lang.Object).
429 keep_alive->do_oop(adr_subklass());
430 keep_alive->do_oop(adr_next_sibling());
431 }
432 }
433
434
435 void Klass::remove_unshareable_info() {
436 if (oop_is_instance()) {
437 instanceKlass* ik = (instanceKlass*)this;
438 if (ik->is_linked()) {
439 ik->unlink_class();
440 }
441 }
442 set_subklass(NULL);
443 set_next_sibling(NULL);
444 }
445
446
447 klassOop Klass::array_klass_or_null(int rank) {
448 EXCEPTION_MARK;
449 // No exception can be thrown by array_klass_impl when called with or_null == true.
450 // (In anycase, the execption mark will fail if it do so)
451 return array_klass_impl(true, rank, THREAD);
452 }
453
454
455 klassOop Klass::array_klass_or_null() {
456 EXCEPTION_MARK;
457 // No exception can be thrown by array_klass_impl when called with or_null == true.
458 // (In anycase, the execption mark will fail if it do so)
459 return array_klass_impl(true, THREAD);
460 }
461
462
463 klassOop Klass::array_klass_impl(bool or_null, int rank, TRAPS) {
464 fatal("array_klass should be dispatched to instanceKlass, objArrayKlass or typeArrayKlass");
465 return NULL;
466 }
467
468
469 klassOop Klass::array_klass_impl(bool or_null, TRAPS) {
470 fatal("array_klass should be dispatched to instanceKlass, objArrayKlass or typeArrayKlass");
471 return NULL;
472 }
473
474
475 void Klass::with_array_klasses_do(void f(klassOop k)) {
476 f(as_klassOop());
477 }
478
479
480 const char* Klass::external_name() const {
481 if (oop_is_instance()) {
482 instanceKlass* ik = (instanceKlass*) this;
483 if (ik->is_anonymous()) {
484 assert(AnonymousClasses, "");
485 intptr_t hash = ik->java_mirror()->identity_hash();
486 char hash_buf[40];
487 sprintf(hash_buf, "/" UINTX_FORMAT, (uintx)hash);
488 size_t hash_len = strlen(hash_buf);
489
490 size_t result_len = name()->utf8_length();
491 char* result = NEW_RESOURCE_ARRAY(char, result_len + hash_len + 1);
492 name()->as_klass_external_name(result, (int) result_len + 1);
493 assert(strlen(result) == result_len, "");
494 strcpy(result + result_len, hash_buf);
495 assert(strlen(result) == result_len + hash_len, "");
496 return result;
497 }
498 }
499 if (name() == NULL) return "<unknown>";
500 return name()->as_klass_external_name();
501 }
502
503
504 const char* Klass::signature_name() const {
505 if (name() == NULL) return "<unknown>";
506 return name()->as_C_string();
507 }
508
509 // Unless overridden, modifier_flags is 0.
510 jint Klass::compute_modifier_flags(TRAPS) const {
511 return 0;
512 }
513
514 int Klass::atomic_incr_biased_lock_revocation_count() {
515 return (int) Atomic::add(1, &_biased_lock_revocation_count);
516 }
517
518 // Unless overridden, jvmti_class_status has no flags set.
519 jint Klass::jvmti_class_status() const {
520 return 0;
521 }
522
523 // Printing
524
525 void Klass::oop_print_on(oop obj, outputStream* st) {
526 ResourceMark rm;
527 // print title
528 st->print_cr("%s ", internal_name());
529 obj->print_address_on(st);
530
531 if (WizardMode) {
532 // print header
533 obj->mark()->print_on(st);
534 }
535
536 // print class
537 st->print(" - klass: ");
538 obj->klass()->print_value_on(st);
539 st->cr();
540 }
541
542 void Klass::oop_print_value_on(oop obj, outputStream* st) {
543 // print title
544 ResourceMark rm; // Cannot print in debug mode without this
545 st->print("%s", internal_name());
546 obj->print_address_on(st);
547 }
548
549 // Verification
550
551 void Klass::oop_verify_on(oop obj, outputStream* st) {
552 guarantee(obj->is_oop(), "should be oop");
553 guarantee(obj->klass()->is_perm(), "should be in permspace");
554 guarantee(obj->klass()->is_klass(), "klass field is not a klass");
555 }
556
557
558 void Klass::oop_verify_old_oop(oop obj, oop* p, bool allow_dirty) {
559 /* $$$ I think this functionality should be handled by verification of
560 RememberedSet::verify_old_oop(obj, p, allow_dirty, false);
561 the card table. */
562 }
563 void Klass::oop_verify_old_oop(oop obj, narrowOop* p, bool allow_dirty) { }
564
565 #ifndef PRODUCT
566
567 void Klass::verify_vtable_index(int i) {
568 assert(oop_is_instance() || oop_is_array(), "only instanceKlass and arrayKlass have vtables");
569 if (oop_is_instance()) {
570 assert(i>=0 && i<((instanceKlass*)this)->vtable_length()/vtableEntry::size(), "index out of bounds");
571 } else {
572 assert(i>=0 && i<((arrayKlass*)this)->vtable_length()/vtableEntry::size(), "index out of bounds");
573 }
574 }
575
576 #endif