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