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