1 /*
2 * Copyright (c) 2012, 2013, 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 // A ClassLoaderData identifies the full set of class types that a class
26 // loader's name resolution strategy produces for a given configuration of the
27 // class loader.
28 // Class types in the ClassLoaderData may be defined by from class file binaries
29 // provided by the class loader, or from other class loader it interacts with
30 // according to its name resolution strategy.
31 //
32 // Class loaders that implement a deterministic name resolution strategy
33 // (including with respect to their delegation behavior), such as the boot, the
34 // extension, and the system loaders of the JDK's built-in class loader
35 // hierarchy, always produce the same linkset for a given configuration.
36 //
37 // ClassLoaderData carries information related to a linkset (e.g.,
38 // metaspace holding its klass definitions).
39 // The System Dictionary and related data structures (e.g., placeholder table,
40 // loader constraints table) as well as the runtime representation of classes
41 // only reference ClassLoaderData.
42 //
43 // Instances of java.lang.ClassLoader holds a pointer to a ClassLoaderData that
44 // that represent the loader's "linking domain" in the JVM.
45 //
46 // The bootstrap loader (represented by NULL) also has a ClassLoaderData,
47 // the singleton class the_null_class_loader_data().
48
49 #include "precompiled.hpp"
50 #include "classfile/classLoaderData.hpp"
51 #include "classfile/classLoaderData.inline.hpp"
52 #include "classfile/javaClasses.hpp"
53 #include "classfile/metadataOnStackMark.hpp"
54 #include "classfile/systemDictionary.hpp"
55 #include "code/codeCache.hpp"
56 #include "memory/gcLocker.hpp"
57 #include "memory/metadataFactory.hpp"
58 #include "memory/metaspaceShared.hpp"
59 #include "memory/oopFactory.hpp"
60 #include "runtime/jniHandles.hpp"
61 #include "runtime/mutex.hpp"
62 #include "runtime/safepoint.hpp"
63 #include "runtime/synchronizer.hpp"
64 #include "utilities/growableArray.hpp"
65 #include "utilities/ostream.hpp"
66
67 ClassLoaderData * ClassLoaderData::_the_null_class_loader_data = NULL;
68
69 ClassLoaderData::ClassLoaderData(Handle h_class_loader, bool is_anonymous) :
70 _class_loader(h_class_loader()),
71 _is_anonymous(is_anonymous), _keep_alive(is_anonymous), // initially
72 _metaspace(NULL), _unloading(false), _klasses(NULL),
73 _claimed(0), _jmethod_ids(NULL), _handles(NULL), _deallocate_list(NULL),
74 _next(NULL), _dependencies(),
75 _metaspace_lock(new Mutex(Monitor::leaf+1, "Metaspace allocation lock", true)) {
76 // empty
77 }
78
79 void ClassLoaderData::init_dependencies(TRAPS) {
80 _dependencies.init(CHECK);
81 }
82
83 void ClassLoaderData::Dependencies::init(TRAPS) {
84 // Create empty dependencies array to add to. CMS requires this to be
85 // an oop so that it can track additions via card marks. We think.
86 _list_head = oopFactory::new_objectArray(2, CHECK);
87 }
88
89 bool ClassLoaderData::claim() {
90 if (_claimed == 1) {
91 return false;
92 }
93
94 return (int) Atomic::cmpxchg(1, &_claimed, 0) == 0;
95 }
96
97 void ClassLoaderData::oops_do(OopClosure* f, KlassClosure* klass_closure, bool must_claim) {
98 if (must_claim && !claim()) {
99 return;
100 }
101
102 f->do_oop(&_class_loader);
103 _dependencies.oops_do(f);
104 _handles->oops_do(f);
105 if (klass_closure != NULL) {
106 classes_do(klass_closure);
107 }
108 }
109
110 void ClassLoaderData::Dependencies::oops_do(OopClosure* f) {
111 f->do_oop((oop*)&_list_head);
112 }
113
114 void ClassLoaderData::classes_do(KlassClosure* klass_closure) {
115 for (Klass* k = _klasses; k != NULL; k = k->next_link()) {
116 klass_closure->do_klass(k);
117 assert(k != k->next_link(), "no loops!");
118 }
119 }
120
121 void ClassLoaderData::classes_do(void f(InstanceKlass*)) {
122 for (Klass* k = _klasses; k != NULL; k = k->next_link()) {
123 if (k->oop_is_instance()) {
124 f(InstanceKlass::cast(k));
125 }
126 assert(k != k->next_link(), "no loops!");
127 }
128 }
129
130 void ClassLoaderData::record_dependency(Klass* k, TRAPS) {
131 ClassLoaderData * const from_cld = this;
132 ClassLoaderData * const to_cld = k->class_loader_data();
133
134 // Dependency to the null class loader data doesn't need to be recorded
135 // because the null class loader data never goes away.
136 if (to_cld->is_the_null_class_loader_data()) {
137 return;
138 }
139
140 oop to;
141 if (to_cld->is_anonymous()) {
142 // Anonymous class dependencies are through the mirror.
143 to = k->java_mirror();
144 } else {
145 to = to_cld->class_loader();
146
147 // If from_cld is anonymous, even if it's class_loader is a parent of 'to'
148 // we still have to add it. The class_loader won't keep from_cld alive.
149 if (!from_cld->is_anonymous()) {
150 // Check that this dependency isn't from the same or parent class_loader
151 oop from = from_cld->class_loader();
152
153 oop curr = from;
154 while (curr != NULL) {
155 if (curr == to) {
156 return; // this class loader is in the parent list, no need to add it.
157 }
158 curr = java_lang_ClassLoader::parent(curr);
159 }
160 }
161 }
162
163 // It's a dependency we won't find through GC, add it. This is relatively rare
164 // Must handle over GC point.
165 Handle dependency(THREAD, to);
166 from_cld->_dependencies.add(dependency, CHECK);
167 }
168
169
170 void ClassLoaderData::Dependencies::add(Handle dependency, TRAPS) {
171 // Check first if this dependency is already in the list.
172 // Save a pointer to the last to add to under the lock.
173 objArrayOop ok = _list_head;
174 objArrayOop last = NULL;
175 while (ok != NULL) {
176 last = ok;
177 if (ok->obj_at(0) == dependency()) {
178 // Don't need to add it
179 return;
180 }
181 ok = (objArrayOop)ok->obj_at(1);
182 }
183
184 // Must handle over GC points
185 assert (last != NULL, "dependencies should be initialized");
186 objArrayHandle last_handle(THREAD, last);
187
188 // Create a new dependency node with fields for (class_loader or mirror, next)
189 objArrayOop deps = oopFactory::new_objectArray(2, CHECK);
190 deps->obj_at_put(0, dependency());
191
192 // Must handle over GC points
193 objArrayHandle new_dependency(THREAD, deps);
194
195 // Add the dependency under lock
196 locked_add(last_handle, new_dependency, THREAD);
197 }
198
199 void ClassLoaderData::Dependencies::locked_add(objArrayHandle last_handle,
200 objArrayHandle new_dependency,
201 Thread* THREAD) {
202
203 // Have to lock and put the new dependency on the end of the dependency
204 // array so the card mark for CMS sees that this dependency is new.
205 // Can probably do this lock free with some effort.
206 ObjectLocker ol(Handle(THREAD, _list_head), THREAD);
207
208 oop loader_or_mirror = new_dependency->obj_at(0);
209
210 // Since the dependencies are only added, add to the end.
211 objArrayOop end = last_handle();
212 objArrayOop last = NULL;
213 while (end != NULL) {
214 last = end;
215 // check again if another thread added it to the end.
216 if (end->obj_at(0) == loader_or_mirror) {
217 // Don't need to add it
218 return;
219 }
220 end = (objArrayOop)end->obj_at(1);
221 }
222 assert (last != NULL, "dependencies should be initialized");
223 // fill in the first element with the oop in new_dependency.
224 if (last->obj_at(0) == NULL) {
225 last->obj_at_put(0, new_dependency->obj_at(0));
226 } else {
227 last->obj_at_put(1, new_dependency());
228 }
229 }
230
231 void ClassLoaderDataGraph::clear_claimed_marks() {
232 for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) {
233 cld->clear_claimed();
234 }
235 }
236
237 void ClassLoaderData::add_class(Klass* k) {
238 MutexLockerEx ml(metaspace_lock(), Mutex::_no_safepoint_check_flag);
239 Klass* old_value = _klasses;
240 k->set_next_link(old_value);
241 // link the new item into the list
242 _klasses = k;
243
244 if (TraceClassLoaderData && Verbose && k->class_loader_data() != NULL) {
245 ResourceMark rm;
246 tty->print_cr("[TraceClassLoaderData] Adding k: " PTR_FORMAT " %s to CLD: "
247 PTR_FORMAT " loader: " PTR_FORMAT " %s",
248 k,
249 k->external_name(),
250 k->class_loader_data(),
251 k->class_loader(),
252 loader_name());
253 }
254 }
255
256 // This is called by InstanceKlass::deallocate_contents() to remove the
257 // scratch_class for redefine classes. We need a lock because there it may not
258 // be called at a safepoint if there's an error.
259 void ClassLoaderData::remove_class(Klass* scratch_class) {
260 MutexLockerEx ml(metaspace_lock(), Mutex::_no_safepoint_check_flag);
261 Klass* prev = NULL;
262 for (Klass* k = _klasses; k != NULL; k = k->next_link()) {
263 if (k == scratch_class) {
264 if (prev == NULL) {
265 _klasses = k->next_link();
266 } else {
267 Klass* next = k->next_link();
268 prev->set_next_link(next);
269 }
270 return;
271 }
272 prev = k;
273 assert(k != k->next_link(), "no loops!");
274 }
275 ShouldNotReachHere(); // should have found this class!!
276 }
277
278 void ClassLoaderData::unload() {
279 _unloading = true;
280
281 if (TraceClassLoaderData) {
282 ResourceMark rm;
283 tty->print("[ClassLoaderData: unload loader data "PTR_FORMAT, this);
284 tty->print(" for instance "PTR_FORMAT" of %s", class_loader(),
285 loader_name());
286 if (is_anonymous()) {
287 tty->print(" for anonymous class "PTR_FORMAT " ", _klasses);
288 }
289 tty->print_cr("]");
290 }
291 }
292
293 bool ClassLoaderData::is_alive(BoolObjectClosure* is_alive_closure) const {
294 bool alive =
295 is_anonymous() ?
296 is_alive_closure->do_object_b(_klasses->java_mirror()) :
297 class_loader() == NULL || is_alive_closure->do_object_b(class_loader());
298 assert(!alive || claimed(), "must be claimed");
299 return alive;
300 }
301
302
303 ClassLoaderData::~ClassLoaderData() {
304 Metaspace *m = _metaspace;
305 if (m != NULL) {
306 _metaspace = NULL;
307 // release the metaspace
308 delete m;
309 // release the handles
310 if (_handles != NULL) {
311 JNIHandleBlock::release_block(_handles);
312 _handles = NULL;
313 }
314 }
315
316 // Clear all the JNI handles for methods
317 // These aren't deallocated and are going to look like a leak, but that's
318 // needed because we can't really get rid of jmethodIDs because we don't
319 // know when native code is going to stop using them. The spec says that
320 // they're "invalid" but existing programs likely rely on their being
321 // NULL after class unloading.
322 if (_jmethod_ids != NULL) {
323 Method::clear_jmethod_ids(this);
324 }
325 // Delete lock
326 delete _metaspace_lock;
327
328 // Delete free list
329 if (_deallocate_list != NULL) {
330 delete _deallocate_list;
331 }
332 }
333
334 /**
335 * Returns true if this class loader data is for the extension class loader.
336 */
337 bool ClassLoaderData::is_ext_class_loader_data() const {
338 return SystemDictionary::is_ext_class_loader(class_loader());
339 }
340
341 Metaspace* ClassLoaderData::metaspace_non_null() {
342 assert(!DumpSharedSpaces, "wrong metaspace!");
343 // If the metaspace has not been allocated, create a new one. Might want
344 // to create smaller arena for Reflection class loaders also.
345 // The reason for the delayed allocation is because some class loaders are
346 // simply for delegating with no metadata of their own.
347 if (_metaspace == NULL) {
348 MutexLockerEx ml(metaspace_lock(), Mutex::_no_safepoint_check_flag);
349 // Check again if metaspace has been allocated while we were getting this lock.
350 if (_metaspace != NULL) {
351 return _metaspace;
352 }
353 if (this == the_null_class_loader_data()) {
354 assert (class_loader() == NULL, "Must be");
355 set_metaspace(new Metaspace(_metaspace_lock, Metaspace::BootMetaspaceType));
356 } else if (is_anonymous()) {
357 if (TraceClassLoaderData && Verbose && class_loader() != NULL) {
358 tty->print_cr("is_anonymous: %s", class_loader()->klass()->internal_name());
359 }
360 set_metaspace(new Metaspace(_metaspace_lock, Metaspace::AnonymousMetaspaceType));
361 } else if (class_loader()->is_a(SystemDictionary::reflect_DelegatingClassLoader_klass())) {
362 if (TraceClassLoaderData && Verbose && class_loader() != NULL) {
363 tty->print_cr("is_reflection: %s", class_loader()->klass()->internal_name());
364 }
365 set_metaspace(new Metaspace(_metaspace_lock, Metaspace::ReflectionMetaspaceType));
366 } else {
367 set_metaspace(new Metaspace(_metaspace_lock, Metaspace::StandardMetaspaceType));
368 }
369 }
370 return _metaspace;
371 }
372
373 JNIHandleBlock* ClassLoaderData::handles() const { return _handles; }
374 void ClassLoaderData::set_handles(JNIHandleBlock* handles) { _handles = handles; }
375
376 jobject ClassLoaderData::add_handle(Handle h) {
377 MutexLockerEx ml(metaspace_lock(), Mutex::_no_safepoint_check_flag);
378 if (handles() == NULL) {
379 set_handles(JNIHandleBlock::allocate_block());
380 }
381 return handles()->allocate_handle(h());
382 }
383
384 // Add this metadata pointer to be freed when it's safe. This is only during
385 // class unloading because Handles might point to this metadata field.
386 void ClassLoaderData::add_to_deallocate_list(Metadata* m) {
387 // Metadata in shared region isn't deleted.
388 if (!m->is_shared()) {
389 MutexLockerEx ml(metaspace_lock(), Mutex::_no_safepoint_check_flag);
390 if (_deallocate_list == NULL) {
391 _deallocate_list = new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(100, true);
392 }
393 _deallocate_list->append_if_missing(m);
394 }
395 }
396
397 // Deallocate free metadata on the free list. How useful the PermGen was!
398 void ClassLoaderData::free_deallocate_list() {
399 // Don't need lock, at safepoint
400 assert(SafepointSynchronize::is_at_safepoint(), "only called at safepoint");
401 if (_deallocate_list == NULL) {
402 return;
403 }
404 // Go backwards because this removes entries that are freed.
405 for (int i = _deallocate_list->length() - 1; i >= 0; i--) {
406 Metadata* m = _deallocate_list->at(i);
407 if (!m->on_stack()) {
408 _deallocate_list->remove_at(i);
409 // There are only three types of metadata that we deallocate directly.
410 // Cast them so they can be used by the template function.
411 if (m->is_method()) {
412 MetadataFactory::free_metadata(this, (Method*)m);
413 } else if (m->is_constantPool()) {
414 MetadataFactory::free_metadata(this, (ConstantPool*)m);
415 } else if (m->is_klass()) {
416 MetadataFactory::free_metadata(this, (InstanceKlass*)m);
417 } else {
418 ShouldNotReachHere();
419 }
420 }
421 }
422 }
423
424 // These anonymous class loaders are to contain classes used for JSR292
425 ClassLoaderData* ClassLoaderData::anonymous_class_loader_data(oop loader, TRAPS) {
426 // Add a new class loader data to the graph.
427 return ClassLoaderDataGraph::add(loader, true, CHECK_NULL);
428 }
429
430 const char* ClassLoaderData::loader_name() {
431 // Handles null class loader
432 return SystemDictionary::loader_name(class_loader());
433 }
434
435 #ifndef PRODUCT
436 // Define to dump klasses
437 #undef CLD_DUMP_KLASSES
438
439 void ClassLoaderData::dump(outputStream * const out) {
440 ResourceMark rm;
441 out->print("ClassLoaderData CLD: "PTR_FORMAT", loader: "PTR_FORMAT", loader_klass: "PTR_FORMAT" %s {",
442 this, class_loader(),
443 class_loader() != NULL ? class_loader()->klass() : NULL, loader_name());
444 if (claimed()) out->print(" claimed ");
445 if (is_unloading()) out->print(" unloading ");
446 out->print(" handles " INTPTR_FORMAT, handles());
447 out->cr();
448 if (metaspace_or_null() != NULL) {
449 out->print_cr("metaspace: " PTR_FORMAT, metaspace_or_null());
450 metaspace_or_null()->dump(out);
451 } else {
452 out->print_cr("metaspace: NULL");
453 }
454
455 #ifdef CLD_DUMP_KLASSES
456 if (Verbose) {
457 ResourceMark rm;
458 Klass* k = _klasses;
459 while (k != NULL) {
460 out->print_cr("klass "PTR_FORMAT", %s, CT: %d, MUT: %d", k, k->name()->as_C_string(),
461 k->has_modified_oops(), k->has_accumulated_modified_oops());
462 assert(k != k->next_link(), "no loops!");
463 k = k->next_link();
464 }
465 }
466 #endif // CLD_DUMP_KLASSES
467 #undef CLD_DUMP_KLASSES
468 if (_jmethod_ids != NULL) {
469 Method::print_jmethod_ids(this, out);
470 }
471 out->print_cr("}");
472 }
473 #endif // PRODUCT
474
475 void ClassLoaderData::verify() {
476 oop cl = class_loader();
477
478 guarantee(this == class_loader_data(cl) || is_anonymous(), "Must be the same");
479 guarantee(cl != NULL || this == ClassLoaderData::the_null_class_loader_data() || is_anonymous(), "must be");
480
481 // Verify the integrity of the allocated space.
482 if (metaspace_or_null() != NULL) {
483 metaspace_or_null()->verify();
484 }
485
486 for (Klass* k = _klasses; k != NULL; k = k->next_link()) {
487 guarantee(k->class_loader_data() == this, "Must be the same");
488 k->verify();
489 assert(k != k->next_link(), "no loops!");
490 }
491 }
492
493
494 // GC root of class loader data created.
495 ClassLoaderData* ClassLoaderDataGraph::_head = NULL;
496 ClassLoaderData* ClassLoaderDataGraph::_unloading = NULL;
497 ClassLoaderData* ClassLoaderDataGraph::_saved_head = NULL;
498
499 // Add a new class loader data node to the list. Assign the newly created
500 // ClassLoaderData into the java/lang/ClassLoader object as a hidden field
501 ClassLoaderData* ClassLoaderDataGraph::add(Handle loader, bool is_anonymous, TRAPS) {
502 // Not assigned a class loader data yet.
503 // Create one.
504 ClassLoaderData* cld = new ClassLoaderData(loader, is_anonymous);
505 cld->init_dependencies(THREAD);
506 if (HAS_PENDING_EXCEPTION) {
507 delete cld;
508 return NULL;
509 }
510
511 No_Safepoint_Verifier no_safepoints; // nothing is keeping the dependencies array in cld alive
512 // make sure we don't encounter a GC until we've inserted
513 // cld into the CLDG
514
515 if (!is_anonymous) {
516 ClassLoaderData** cld_addr = java_lang_ClassLoader::loader_data_addr(loader());
517 if (cld_addr != NULL) {
518 // First, Atomically set it
519 ClassLoaderData* old = (ClassLoaderData*) Atomic::cmpxchg_ptr(cld, cld_addr, NULL);
520 if (old != NULL) {
521 delete cld;
522 // Returns the data.
523 return old;
524 }
525 }
526 }
527
528 // We won the race, and therefore the task of adding the data to the list of
529 // class loader data
530 ClassLoaderData** list_head = &_head;
531 ClassLoaderData* next = _head;
532
533 do {
534 cld->set_next(next);
535 ClassLoaderData* exchanged = (ClassLoaderData*)Atomic::cmpxchg_ptr(cld, list_head, next);
536 if (exchanged == next) {
537 if (TraceClassLoaderData) {
538 ResourceMark rm;
539 tty->print("[ClassLoaderData: ");
540 tty->print("create class loader data "PTR_FORMAT, cld);
541 tty->print(" for instance "PTR_FORMAT" of %s", cld->class_loader(),
542 cld->loader_name());
543 tty->print_cr("]");
544 }
545 return cld;
546 }
547 next = exchanged;
548 } while (true);
549
550 }
551
552 void ClassLoaderDataGraph::oops_do(OopClosure* f, KlassClosure* klass_closure, bool must_claim) {
553 for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) {
554 cld->oops_do(f, klass_closure, must_claim);
555 }
556 }
557
558 void ClassLoaderDataGraph::keep_alive_oops_do(OopClosure* f, KlassClosure* klass_closure, bool must_claim) {
559 for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) {
560 if (cld->keep_alive()) {
561 cld->oops_do(f, klass_closure, must_claim);
562 }
563 }
564 }
565
566 void ClassLoaderDataGraph::always_strong_oops_do(OopClosure* f, KlassClosure* klass_closure, bool must_claim) {
567 if (ClassUnloading) {
568 ClassLoaderData::the_null_class_loader_data()->oops_do(f, klass_closure, must_claim);
569 // keep any special CLDs alive.
570 ClassLoaderDataGraph::keep_alive_oops_do(f, klass_closure, must_claim);
571 } else {
572 ClassLoaderDataGraph::oops_do(f, klass_closure, must_claim);
573 }
574 }
575
576 void ClassLoaderDataGraph::classes_do(KlassClosure* klass_closure) {
577 for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) {
578 cld->classes_do(klass_closure);
579 }
580 }
581
582 GrowableArray<ClassLoaderData*>* ClassLoaderDataGraph::new_clds() {
583 assert(_head == NULL || _saved_head != NULL, "remember_new_clds(true) not called?");
584
585 GrowableArray<ClassLoaderData*>* array = new GrowableArray<ClassLoaderData*>();
586
587 // The CLDs in [_head, _saved_head] were all added during last call to remember_new_clds(true);
588 ClassLoaderData* curr = _head;
589 while (curr != _saved_head) {
590 if (!curr->claimed()) {
591 array->push(curr);
592
593 if (TraceClassLoaderData) {
594 tty->print("[ClassLoaderData] found new CLD: ");
595 curr->print_value_on(tty);
596 tty->cr();
597 }
598 }
599
600 curr = curr->_next;
601 }
602
603 return array;
604 }
605
606 #ifndef PRODUCT
607 // for debugging and hsfind(x)
608 bool ClassLoaderDataGraph::contains(address x) {
609 // I think we need the _metaspace_lock taken here because the class loader
610 // data graph could be changing while we are walking it (new entries added,
611 // new entries being unloaded, etc).
612 if (DumpSharedSpaces) {
613 // There are only two metaspaces to worry about.
614 ClassLoaderData* ncld = ClassLoaderData::the_null_class_loader_data();
615 return (ncld->ro_metaspace()->contains(x) || ncld->rw_metaspace()->contains(x));
616 }
617
618 if (UseSharedSpaces && MetaspaceShared::is_in_shared_space(x)) {
619 return true;
620 }
621
622 for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) {
623 if (cld->metaspace_or_null() != NULL && cld->metaspace_or_null()->contains(x)) {
624 return true;
625 }
626 }
627
628 // Could also be on an unloading list which is okay, ie. still allocated
629 // for a little while.
630 for (ClassLoaderData* ucld = _unloading; ucld != NULL; ucld = ucld->next()) {
631 if (ucld->metaspace_or_null() != NULL && ucld->metaspace_or_null()->contains(x)) {
632 return true;
633 }
634 }
635 return false;
636 }
637
638 bool ClassLoaderDataGraph::contains_loader_data(ClassLoaderData* loader_data) {
639 for (ClassLoaderData* data = _head; data != NULL; data = data->next()) {
640 if (loader_data == data) {
641 return true;
642 }
643 }
644
645 return false;
646 }
647 #endif // PRODUCT
648
649
650 // Move class loader data from main list to the unloaded list for unloading
651 // and deallocation later.
652 bool ClassLoaderDataGraph::do_unloading(BoolObjectClosure* is_alive_closure) {
653 ClassLoaderData* data = _head;
654 ClassLoaderData* prev = NULL;
655 bool seen_dead_loader = false;
656 // mark metadata seen on the stack and code cache so we can delete
657 // unneeded entries.
658 bool has_redefined_a_class = JvmtiExport::has_redefined_a_class();
659 MetadataOnStackMark md_on_stack;
660 while (data != NULL) {
661 if (data->keep_alive() || data->is_alive(is_alive_closure)) {
662 if (has_redefined_a_class) {
663 data->classes_do(InstanceKlass::purge_previous_versions);
664 }
665 data->free_deallocate_list();
666 prev = data;
667 data = data->next();
668 continue;
669 }
670 seen_dead_loader = true;
671 ClassLoaderData* dead = data;
672 dead->unload();
673 data = data->next();
674 // Remove from loader list.
675 if (prev != NULL) {
676 prev->set_next(data);
677 } else {
678 assert(dead == _head, "sanity check");
679 _head = data;
680 }
681 dead->set_next(_unloading);
682 _unloading = dead;
683 }
684 return seen_dead_loader;
685 }
686
687 void ClassLoaderDataGraph::purge() {
688 ClassLoaderData* list = _unloading;
689 _unloading = NULL;
690 ClassLoaderData* next = list;
691 while (next != NULL) {
692 ClassLoaderData* purge_me = next;
693 next = purge_me->next();
694 delete purge_me;
695 }
696 Metaspace::purge();
697 }
698
699 // CDS support
700
701 // Global metaspaces for writing information to the shared archive. When
702 // application CDS is supported, we may need one per metaspace, so this
703 // sort of looks like it.
704 Metaspace* ClassLoaderData::_ro_metaspace = NULL;
705 Metaspace* ClassLoaderData::_rw_metaspace = NULL;
706 static bool _shared_metaspaces_initialized = false;
707
708 // Initialize shared metaspaces (change to call from somewhere not lazily)
709 void ClassLoaderData::initialize_shared_metaspaces() {
710 assert(DumpSharedSpaces, "only use this for dumping shared spaces");
711 assert(this == ClassLoaderData::the_null_class_loader_data(),
712 "only supported for null loader data for now");
713 assert (!_shared_metaspaces_initialized, "only initialize once");
714 MutexLockerEx ml(metaspace_lock(), Mutex::_no_safepoint_check_flag);
715 _ro_metaspace = new Metaspace(_metaspace_lock, Metaspace::ROMetaspaceType);
716 _rw_metaspace = new Metaspace(_metaspace_lock, Metaspace::ReadWriteMetaspaceType);
717 _shared_metaspaces_initialized = true;
718 }
719
720 Metaspace* ClassLoaderData::ro_metaspace() {
721 assert(_ro_metaspace != NULL, "should already be initialized");
722 return _ro_metaspace;
723 }
724
725 Metaspace* ClassLoaderData::rw_metaspace() {
726 assert(_rw_metaspace != NULL, "should already be initialized");
727 return _rw_metaspace;
728 }
729
730
731 ClassLoaderDataGraphMetaspaceIterator::ClassLoaderDataGraphMetaspaceIterator() {
732 _data = ClassLoaderDataGraph::_head;
733 }
734
735 ClassLoaderDataGraphMetaspaceIterator::~ClassLoaderDataGraphMetaspaceIterator() {}
736
737 #ifndef PRODUCT
738 // callable from debugger
739 extern "C" int print_loader_data_graph() {
740 ClassLoaderDataGraph::dump_on(tty);
741 return 0;
742 }
743
744 void ClassLoaderDataGraph::verify() {
745 for (ClassLoaderData* data = _head; data != NULL; data = data->next()) {
746 data->verify();
747 }
748 }
749
750 void ClassLoaderDataGraph::dump_on(outputStream * const out) {
751 for (ClassLoaderData* data = _head; data != NULL; data = data->next()) {
752 data->dump(out);
753 }
754 MetaspaceAux::dump(out);
755 }
756 #endif // PRODUCT
757
758 void ClassLoaderData::print_value_on(outputStream* out) const {
759 if (class_loader() == NULL) {
760 out->print("NULL class_loader");
761 } else {
762 out->print("class loader "PTR_FORMAT, this);
763 class_loader()->print_value_on(out);
764 }
765 }