1 /*
2 * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/classLoaderDataGraph.hpp"
27 #include "classfile/javaClasses.inline.hpp"
28 #include "classfile/symbolTable.hpp"
29 #include "classfile/vmClasses.hpp"
30 #include "classfile/vmSymbols.hpp"
31 #include "gc/shared/collectedHeap.hpp"
32 #include "jvmtifiles/jvmtiEnv.hpp"
33 #include "logging/log.hpp"
34 #include "memory/allocation.inline.hpp"
35 #include "memory/resourceArea.hpp"
36 #include "memory/universe.hpp"
37 #include "oops/access.inline.hpp"
38 #include "oops/arrayOop.hpp"
39 #include "oops/constantPool.inline.hpp"
40 #include "oops/instanceMirrorKlass.hpp"
41 #include "oops/klass.inline.hpp"
42 #include "oops/objArrayKlass.hpp"
43 #include "oops/objArrayOop.inline.hpp"
44 #include "oops/oop.inline.hpp"
45 #include "oops/typeArrayOop.inline.hpp"
46 #include "prims/jvmtiEventController.hpp"
47 #include "prims/jvmtiEventController.inline.hpp"
48 #include "prims/jvmtiExport.hpp"
49 #include "prims/jvmtiImpl.hpp"
50 #include "prims/jvmtiTagMap.hpp"
51 #include "prims/jvmtiTagMapTable.hpp"
52 #include "runtime/biasedLocking.hpp"
53 #include "runtime/deoptimization.hpp"
54 #include "runtime/frame.inline.hpp"
55 #include "runtime/handles.inline.hpp"
56 #include "runtime/interfaceSupport.inline.hpp"
57 #include "runtime/javaCalls.hpp"
58 #include "runtime/jniHandles.inline.hpp"
59 #include "runtime/mutex.hpp"
60 #include "runtime/mutexLocker.hpp"
61 #include "runtime/reflectionUtils.hpp"
62 #include "runtime/safepoint.hpp"
63 #include "runtime/timerTrace.hpp"
64 #include "runtime/thread.inline.hpp"
65 #include "runtime/threadSMR.hpp"
66 #include "runtime/vframe.hpp"
67 #include "runtime/vmThread.hpp"
68 #include "runtime/vmOperations.hpp"
69 #include "utilities/macros.hpp"
70
71 bool JvmtiTagMap::_has_object_free_events = false;
72
73 // create a JvmtiTagMap
74 JvmtiTagMap::JvmtiTagMap(JvmtiEnv* env) :
75 _env(env),
76 _lock(Mutex::nonleaf+1, "JvmtiTagMap_lock", Mutex::_allow_vm_block_flag,
77 Mutex::_safepoint_check_never),
78 _needs_rehashing(false),
79 _needs_cleaning(false),
80 _posting_events(false) {
81
82 assert(JvmtiThreadState_lock->is_locked(), "sanity check");
83 assert(((JvmtiEnvBase *)env)->tag_map() == NULL, "tag map already exists for environment");
84
85 _hashmap = new JvmtiTagMapTable();
86
87 // finally add us to the environment
88 ((JvmtiEnvBase *)env)->release_set_tag_map(this);
89 }
90
91 // destroy a JvmtiTagMap
92 JvmtiTagMap::~JvmtiTagMap() {
93
94 // no lock acquired as we assume the enclosing environment is
95 // also being destroyed.
96 ((JvmtiEnvBase *)_env)->set_tag_map(NULL);
97
98 // finally destroy the hashmap
99 delete _hashmap;
100 _hashmap = NULL;
101 }
102
103 // Called by env_dispose() to reclaim memory before deallocation.
104 // Remove all the entries but keep the empty table intact.
105 // This needs the table lock.
106 void JvmtiTagMap::clear() {
107 MutexLocker ml(lock(), Mutex::_no_safepoint_check_flag);
108 _hashmap->clear();
109 }
110
111 // returns the tag map for the given environments. If the tag map
112 // doesn't exist then it is created.
113 JvmtiTagMap* JvmtiTagMap::tag_map_for(JvmtiEnv* env) {
114 JvmtiTagMap* tag_map = ((JvmtiEnvBase*)env)->tag_map_acquire();
115 if (tag_map == NULL) {
116 MutexLocker mu(JvmtiThreadState_lock);
117 tag_map = ((JvmtiEnvBase*)env)->tag_map();
118 if (tag_map == NULL) {
119 tag_map = new JvmtiTagMap(env);
120 }
121 } else {
122 DEBUG_ONLY(JavaThread::current()->check_possible_safepoint());
123 }
124 return tag_map;
125 }
126
127 // iterate over all entries in the tag map.
128 void JvmtiTagMap::entry_iterate(JvmtiTagMapEntryClosure* closure) {
129 hashmap()->entry_iterate(closure);
130 }
131
132 // returns true if the hashmaps are empty
133 bool JvmtiTagMap::is_empty() {
134 assert(SafepointSynchronize::is_at_safepoint() || is_locked(), "checking");
135 return hashmap()->is_empty();
136 }
137
138 // This checks for posting and rehashing before operations that
139 // this tagmap table.
140 void JvmtiTagMap::check_hashmap(GrowableArray<jlong>* objects) {
141 assert(is_locked(), "checking");
142
143 if (is_empty()) { return; }
144
145 if (_needs_cleaning &&
146 objects != NULL &&
147 env()->is_enabled(JVMTI_EVENT_OBJECT_FREE)) {
148 remove_dead_entries_locked(objects);
149 }
150 if (_needs_rehashing) {
151 log_info(jvmti, table)("TagMap table needs rehashing");
152 hashmap()->rehash();
153 _needs_rehashing = false;
154 }
155 }
156
157 // This checks for posting and rehashing and is called from the heap walks.
158 void JvmtiTagMap::check_hashmaps_for_heapwalk(GrowableArray<jlong>* objects) {
159 assert(SafepointSynchronize::is_at_safepoint(), "called from safepoints");
160
161 // Verify that the tag map tables are valid and unconditionally post events
162 // that are expected to be posted before gc_notification.
163 JvmtiEnvIterator it;
164 for (JvmtiEnv* env = it.first(); env != NULL; env = it.next(env)) {
165 JvmtiTagMap* tag_map = env->tag_map_acquire();
166 if (tag_map != NULL) {
167 // The ZDriver may be walking the hashmaps concurrently so this lock is needed.
168 MutexLocker ml(tag_map->lock(), Mutex::_no_safepoint_check_flag);
169 tag_map->check_hashmap(objects);
170 }
171 }
172 }
173
174 // Return the tag value for an object, or 0 if the object is
175 // not tagged
176 //
177 static inline jlong tag_for(JvmtiTagMap* tag_map, oop o) {
178 JvmtiTagMapEntry* entry = tag_map->hashmap()->find(o);
179 if (entry == NULL) {
180 return 0;
181 } else {
182 jlong tag = entry->tag();
183 assert(tag != 0, "should not be zero");
184 return entry->tag();
185 }
186 }
187
188
189 // A CallbackWrapper is a support class for querying and tagging an object
190 // around a callback to a profiler. The constructor does pre-callback
191 // work to get the tag value, klass tag value, ... and the destructor
192 // does the post-callback work of tagging or untagging the object.
193 //
194 // {
195 // CallbackWrapper wrapper(tag_map, o);
196 //
197 // (*callback)(wrapper.klass_tag(), wrapper.obj_size(), wrapper.obj_tag_p(), ...)
198 //
199 // } // wrapper goes out of scope here which results in the destructor
200 // checking to see if the object has been tagged, untagged, or the
201 // tag value has changed.
202 //
203 class CallbackWrapper : public StackObj {
204 private:
205 JvmtiTagMap* _tag_map;
206 JvmtiTagMapTable* _hashmap;
207 JvmtiTagMapEntry* _entry;
208 oop _o;
209 jlong _obj_size;
210 jlong _obj_tag;
211 jlong _klass_tag;
212
213 protected:
214 JvmtiTagMap* tag_map() const { return _tag_map; }
215
216 // invoked post-callback to tag, untag, or update the tag of an object
217 void inline post_callback_tag_update(oop o, JvmtiTagMapTable* hashmap,
218 JvmtiTagMapEntry* entry, jlong obj_tag);
219 public:
220 CallbackWrapper(JvmtiTagMap* tag_map, oop o) {
221 assert(Thread::current()->is_VM_thread() || tag_map->is_locked(),
222 "MT unsafe or must be VM thread");
223
224 // object to tag
225 _o = o;
226
227 // object size
228 _obj_size = (jlong)_o->size() * wordSize;
229
230 // record the context
231 _tag_map = tag_map;
232 _hashmap = tag_map->hashmap();
233 _entry = _hashmap->find(_o);
234
235 // get object tag
236 _obj_tag = (_entry == NULL) ? 0 : _entry->tag();
237
238 // get the class and the class's tag value
239 assert(vmClasses::Class_klass()->is_mirror_instance_klass(), "Is not?");
240
241 _klass_tag = tag_for(tag_map, _o->klass()->java_mirror());
242 }
243
244 ~CallbackWrapper() {
245 post_callback_tag_update(_o, _hashmap, _entry, _obj_tag);
246 }
247
248 inline jlong* obj_tag_p() { return &_obj_tag; }
249 inline jlong obj_size() const { return _obj_size; }
250 inline jlong obj_tag() const { return _obj_tag; }
251 inline jlong klass_tag() const { return _klass_tag; }
252 };
253
254
255
256 // callback post-callback to tag, untag, or update the tag of an object
257 void inline CallbackWrapper::post_callback_tag_update(oop o,
258 JvmtiTagMapTable* hashmap,
259 JvmtiTagMapEntry* entry,
260 jlong obj_tag) {
261 if (entry == NULL) {
262 if (obj_tag != 0) {
263 // callback has tagged the object
264 assert(Thread::current()->is_VM_thread(), "must be VMThread");
265 hashmap->add(o, obj_tag);
266 }
267 } else {
268 // object was previously tagged - the callback may have untagged
269 // the object or changed the tag value
270 if (obj_tag == 0) {
271 hashmap->remove(o);
272 } else {
273 if (obj_tag != entry->tag()) {
274 entry->set_tag(obj_tag);
275 }
276 }
277 }
278 }
279
280 // An extended CallbackWrapper used when reporting an object reference
281 // to the agent.
282 //
283 // {
284 // TwoOopCallbackWrapper wrapper(tag_map, referrer, o);
285 //
286 // (*callback)(wrapper.klass_tag(),
287 // wrapper.obj_size(),
288 // wrapper.obj_tag_p()
289 // wrapper.referrer_tag_p(), ...)
290 //
291 // } // wrapper goes out of scope here which results in the destructor
292 // checking to see if the referrer object has been tagged, untagged,
293 // or the tag value has changed.
294 //
295 class TwoOopCallbackWrapper : public CallbackWrapper {
296 private:
297 bool _is_reference_to_self;
298 JvmtiTagMapTable* _referrer_hashmap;
299 JvmtiTagMapEntry* _referrer_entry;
300 oop _referrer;
301 jlong _referrer_obj_tag;
302 jlong _referrer_klass_tag;
303 jlong* _referrer_tag_p;
304
305 bool is_reference_to_self() const { return _is_reference_to_self; }
306
307 public:
308 TwoOopCallbackWrapper(JvmtiTagMap* tag_map, oop referrer, oop o) :
309 CallbackWrapper(tag_map, o)
310 {
311 // self reference needs to be handled in a special way
312 _is_reference_to_self = (referrer == o);
313
314 if (_is_reference_to_self) {
315 _referrer_klass_tag = klass_tag();
316 _referrer_tag_p = obj_tag_p();
317 } else {
318 _referrer = referrer;
319 // record the context
320 _referrer_hashmap = tag_map->hashmap();
321 _referrer_entry = _referrer_hashmap->find(_referrer);
322
323 // get object tag
324 _referrer_obj_tag = (_referrer_entry == NULL) ? 0 : _referrer_entry->tag();
325 _referrer_tag_p = &_referrer_obj_tag;
326
327 // get referrer class tag.
328 _referrer_klass_tag = tag_for(tag_map, _referrer->klass()->java_mirror());
329 }
330 }
331
332 ~TwoOopCallbackWrapper() {
333 if (!is_reference_to_self()){
334 post_callback_tag_update(_referrer,
335 _referrer_hashmap,
336 _referrer_entry,
337 _referrer_obj_tag);
338 }
339 }
340
341 // address of referrer tag
342 // (for a self reference this will return the same thing as obj_tag_p())
343 inline jlong* referrer_tag_p() { return _referrer_tag_p; }
344
345 // referrer's class tag
346 inline jlong referrer_klass_tag() { return _referrer_klass_tag; }
347 };
348
349 // tag an object
350 //
351 // This function is performance critical. If many threads attempt to tag objects
352 // around the same time then it's possible that the Mutex associated with the
353 // tag map will be a hot lock.
354 void JvmtiTagMap::set_tag(jobject object, jlong tag) {
355 MutexLocker ml(lock(), Mutex::_no_safepoint_check_flag);
356
357 // SetTag should not post events because the JavaThread has to
358 // transition to native for the callback and this cannot stop for
359 // safepoints with the hashmap lock held.
360 check_hashmap(NULL); /* don't collect dead objects */
361
362 // resolve the object
363 oop o = JNIHandles::resolve_non_null(object);
364
365 // see if the object is already tagged
366 JvmtiTagMapTable* hashmap = _hashmap;
367 JvmtiTagMapEntry* entry = hashmap->find(o);
368
369 // if the object is not already tagged then we tag it
370 if (entry == NULL) {
371 if (tag != 0) {
372 hashmap->add(o, tag);
373 } else {
374 // no-op
375 }
376 } else {
377 // if the object is already tagged then we either update
378 // the tag (if a new tag value has been provided)
379 // or remove the object if the new tag value is 0.
380 if (tag == 0) {
381 hashmap->remove(o);
382 } else {
383 entry->set_tag(tag);
384 }
385 }
386 }
387
388 // get the tag for an object
389 jlong JvmtiTagMap::get_tag(jobject object) {
390 MutexLocker ml(lock(), Mutex::_no_safepoint_check_flag);
391
392 // GetTag should not post events because the JavaThread has to
393 // transition to native for the callback and this cannot stop for
394 // safepoints with the hashmap lock held.
395 check_hashmap(NULL); /* don't collect dead objects */
396
397 // resolve the object
398 oop o = JNIHandles::resolve_non_null(object);
399
400 return tag_for(this, o);
401 }
402
403
404 // Helper class used to describe the static or instance fields of a class.
405 // For each field it holds the field index (as defined by the JVMTI specification),
406 // the field type, and the offset.
407
408 class ClassFieldDescriptor: public CHeapObj<mtInternal> {
409 private:
410 int _field_index;
411 int _field_offset;
412 char _field_type;
413 public:
414 ClassFieldDescriptor(int index, char type, int offset) :
415 _field_index(index), _field_offset(offset), _field_type(type) {
416 }
417 int field_index() const { return _field_index; }
418 char field_type() const { return _field_type; }
419 int field_offset() const { return _field_offset; }
420 };
421
422 class ClassFieldMap: public CHeapObj<mtInternal> {
423 private:
424 enum {
425 initial_field_count = 5
426 };
427
428 // list of field descriptors
429 GrowableArray<ClassFieldDescriptor*>* _fields;
430
431 // constructor
432 ClassFieldMap();
433
434 // add a field
435 void add(int index, char type, int offset);
436
437 public:
438 ~ClassFieldMap();
439
440 // access
441 int field_count() { return _fields->length(); }
442 ClassFieldDescriptor* field_at(int i) { return _fields->at(i); }
443
444 // functions to create maps of static or instance fields
445 static ClassFieldMap* create_map_of_static_fields(Klass* k);
446 static ClassFieldMap* create_map_of_instance_fields(oop obj);
447 };
448
449 ClassFieldMap::ClassFieldMap() {
450 _fields = new (ResourceObj::C_HEAP, mtServiceability)
451 GrowableArray<ClassFieldDescriptor*>(initial_field_count, mtServiceability);
452 }
453
454 ClassFieldMap::~ClassFieldMap() {
455 for (int i=0; i<_fields->length(); i++) {
456 delete _fields->at(i);
457 }
458 delete _fields;
459 }
460
461 void ClassFieldMap::add(int index, char type, int offset) {
462 ClassFieldDescriptor* field = new ClassFieldDescriptor(index, type, offset);
463 _fields->append(field);
464 }
465
466 // Returns a heap allocated ClassFieldMap to describe the static fields
467 // of the given class.
468 //
469 ClassFieldMap* ClassFieldMap::create_map_of_static_fields(Klass* k) {
470 InstanceKlass* ik = InstanceKlass::cast(k);
471
472 // create the field map
473 ClassFieldMap* field_map = new ClassFieldMap();
474
475 FilteredFieldStream f(ik, false, false);
476 int max_field_index = f.field_count()-1;
477
478 int index = 0;
479 for (FilteredFieldStream fld(ik, true, true); !fld.eos(); fld.next(), index++) {
480 // ignore instance fields
481 if (!fld.access_flags().is_static()) {
482 continue;
483 }
484 field_map->add(max_field_index - index, fld.signature()->char_at(0), fld.offset());
485 }
486 return field_map;
487 }
488
489 // Returns a heap allocated ClassFieldMap to describe the instance fields
490 // of the given class. All instance fields are included (this means public
491 // and private fields declared in superclasses and superinterfaces too).
492 //
493 ClassFieldMap* ClassFieldMap::create_map_of_instance_fields(oop obj) {
494 InstanceKlass* ik = InstanceKlass::cast(obj->klass());
495
496 // create the field map
497 ClassFieldMap* field_map = new ClassFieldMap();
498
499 FilteredFieldStream f(ik, false, false);
500
501 int max_field_index = f.field_count()-1;
502
503 int index = 0;
504 for (FilteredFieldStream fld(ik, false, false); !fld.eos(); fld.next(), index++) {
505 // ignore static fields
506 if (fld.access_flags().is_static()) {
507 continue;
508 }
509 field_map->add(max_field_index - index, fld.signature()->char_at(0), fld.offset());
510 }
511
512 return field_map;
513 }
514
515 // Helper class used to cache a ClassFileMap for the instance fields of
516 // a cache. A JvmtiCachedClassFieldMap can be cached by an InstanceKlass during
517 // heap iteration and avoid creating a field map for each object in the heap
518 // (only need to create the map when the first instance of a class is encountered).
519 //
520 class JvmtiCachedClassFieldMap : public CHeapObj<mtInternal> {
521 private:
522 enum {
523 initial_class_count = 200
524 };
525 ClassFieldMap* _field_map;
526
527 ClassFieldMap* field_map() const { return _field_map; }
528
529 JvmtiCachedClassFieldMap(ClassFieldMap* field_map);
530 ~JvmtiCachedClassFieldMap();
531
532 static GrowableArray<InstanceKlass*>* _class_list;
533 static void add_to_class_list(InstanceKlass* ik);
534
535 public:
536 // returns the field map for a given object (returning map cached
537 // by InstanceKlass if possible
538 static ClassFieldMap* get_map_of_instance_fields(oop obj);
539
540 // removes the field map from all instanceKlasses - should be
541 // called before VM operation completes
542 static void clear_cache();
543
544 // returns the number of ClassFieldMap cached by instanceKlasses
545 static int cached_field_map_count();
546 };
547
548 GrowableArray<InstanceKlass*>* JvmtiCachedClassFieldMap::_class_list;
549
550 JvmtiCachedClassFieldMap::JvmtiCachedClassFieldMap(ClassFieldMap* field_map) {
551 _field_map = field_map;
552 }
553
554 JvmtiCachedClassFieldMap::~JvmtiCachedClassFieldMap() {
555 if (_field_map != NULL) {
556 delete _field_map;
557 }
558 }
559
560 // Marker class to ensure that the class file map cache is only used in a defined
561 // scope.
562 class ClassFieldMapCacheMark : public StackObj {
563 private:
564 static bool _is_active;
565 public:
566 ClassFieldMapCacheMark() {
567 assert(Thread::current()->is_VM_thread(), "must be VMThread");
568 assert(JvmtiCachedClassFieldMap::cached_field_map_count() == 0, "cache not empty");
569 assert(!_is_active, "ClassFieldMapCacheMark cannot be nested");
570 _is_active = true;
571 }
572 ~ClassFieldMapCacheMark() {
573 JvmtiCachedClassFieldMap::clear_cache();
574 _is_active = false;
575 }
576 static bool is_active() { return _is_active; }
577 };
578
579 bool ClassFieldMapCacheMark::_is_active;
580
581
582 // record that the given InstanceKlass is caching a field map
583 void JvmtiCachedClassFieldMap::add_to_class_list(InstanceKlass* ik) {
584 if (_class_list == NULL) {
585 _class_list = new (ResourceObj::C_HEAP, mtServiceability)
586 GrowableArray<InstanceKlass*>(initial_class_count, mtServiceability);
587 }
588 _class_list->push(ik);
589 }
590
591 // returns the instance field map for the given object
592 // (returns field map cached by the InstanceKlass if possible)
593 ClassFieldMap* JvmtiCachedClassFieldMap::get_map_of_instance_fields(oop obj) {
594 assert(Thread::current()->is_VM_thread(), "must be VMThread");
595 assert(ClassFieldMapCacheMark::is_active(), "ClassFieldMapCacheMark not active");
596
597 Klass* k = obj->klass();
598 InstanceKlass* ik = InstanceKlass::cast(k);
599
600 // return cached map if possible
601 JvmtiCachedClassFieldMap* cached_map = ik->jvmti_cached_class_field_map();
602 if (cached_map != NULL) {
603 assert(cached_map->field_map() != NULL, "missing field list");
604 return cached_map->field_map();
605 } else {
606 ClassFieldMap* field_map = ClassFieldMap::create_map_of_instance_fields(obj);
607 cached_map = new JvmtiCachedClassFieldMap(field_map);
608 ik->set_jvmti_cached_class_field_map(cached_map);
609 add_to_class_list(ik);
610 return field_map;
611 }
612 }
613
614 // remove the fields maps cached from all instanceKlasses
615 void JvmtiCachedClassFieldMap::clear_cache() {
616 assert(Thread::current()->is_VM_thread(), "must be VMThread");
617 if (_class_list != NULL) {
618 for (int i = 0; i < _class_list->length(); i++) {
619 InstanceKlass* ik = _class_list->at(i);
620 JvmtiCachedClassFieldMap* cached_map = ik->jvmti_cached_class_field_map();
621 assert(cached_map != NULL, "should not be NULL");
622 ik->set_jvmti_cached_class_field_map(NULL);
623 delete cached_map; // deletes the encapsulated field map
624 }
625 delete _class_list;
626 _class_list = NULL;
627 }
628 }
629
630 // returns the number of ClassFieldMap cached by instanceKlasses
631 int JvmtiCachedClassFieldMap::cached_field_map_count() {
632 return (_class_list == NULL) ? 0 : _class_list->length();
633 }
634
635 // helper function to indicate if an object is filtered by its tag or class tag
636 static inline bool is_filtered_by_heap_filter(jlong obj_tag,
637 jlong klass_tag,
638 int heap_filter) {
639 // apply the heap filter
640 if (obj_tag != 0) {
641 // filter out tagged objects
642 if (heap_filter & JVMTI_HEAP_FILTER_TAGGED) return true;
643 } else {
644 // filter out untagged objects
645 if (heap_filter & JVMTI_HEAP_FILTER_UNTAGGED) return true;
646 }
647 if (klass_tag != 0) {
648 // filter out objects with tagged classes
649 if (heap_filter & JVMTI_HEAP_FILTER_CLASS_TAGGED) return true;
650 } else {
651 // filter out objects with untagged classes.
652 if (heap_filter & JVMTI_HEAP_FILTER_CLASS_UNTAGGED) return true;
653 }
654 return false;
655 }
656
657 // helper function to indicate if an object is filtered by a klass filter
658 static inline bool is_filtered_by_klass_filter(oop obj, Klass* klass_filter) {
659 if (klass_filter != NULL) {
660 if (obj->klass() != klass_filter) {
661 return true;
662 }
663 }
664 return false;
665 }
666
667 // helper function to tell if a field is a primitive field or not
668 static inline bool is_primitive_field_type(char type) {
669 return (type != JVM_SIGNATURE_CLASS && type != JVM_SIGNATURE_ARRAY);
670 }
671
672 // helper function to copy the value from location addr to jvalue.
673 static inline void copy_to_jvalue(jvalue *v, address addr, jvmtiPrimitiveType value_type) {
674 switch (value_type) {
675 case JVMTI_PRIMITIVE_TYPE_BOOLEAN : { v->z = *(jboolean*)addr; break; }
676 case JVMTI_PRIMITIVE_TYPE_BYTE : { v->b = *(jbyte*)addr; break; }
677 case JVMTI_PRIMITIVE_TYPE_CHAR : { v->c = *(jchar*)addr; break; }
678 case JVMTI_PRIMITIVE_TYPE_SHORT : { v->s = *(jshort*)addr; break; }
679 case JVMTI_PRIMITIVE_TYPE_INT : { v->i = *(jint*)addr; break; }
680 case JVMTI_PRIMITIVE_TYPE_LONG : { v->j = *(jlong*)addr; break; }
681 case JVMTI_PRIMITIVE_TYPE_FLOAT : { v->f = *(jfloat*)addr; break; }
682 case JVMTI_PRIMITIVE_TYPE_DOUBLE : { v->d = *(jdouble*)addr; break; }
683 default: ShouldNotReachHere();
684 }
685 }
686
687 // helper function to invoke string primitive value callback
688 // returns visit control flags
689 static jint invoke_string_value_callback(jvmtiStringPrimitiveValueCallback cb,
690 CallbackWrapper* wrapper,
691 oop str,
692 void* user_data)
693 {
694 assert(str->klass() == vmClasses::String_klass(), "not a string");
695
696 typeArrayOop s_value = java_lang_String::value(str);
697
698 // JDK-6584008: the value field may be null if a String instance is
699 // partially constructed.
700 if (s_value == NULL) {
701 return 0;
702 }
703 // get the string value and length
704 // (string value may be offset from the base)
705 int s_len = java_lang_String::length(str);
706 bool is_latin1 = java_lang_String::is_latin1(str);
707 jchar* value;
708 if (s_len > 0) {
709 if (!is_latin1) {
710 value = s_value->char_at_addr(0);
711 } else {
712 // Inflate latin1 encoded string to UTF16
713 jchar* buf = NEW_C_HEAP_ARRAY(jchar, s_len, mtInternal);
714 for (int i = 0; i < s_len; i++) {
715 buf[i] = ((jchar) s_value->byte_at(i)) & 0xff;
716 }
717 value = &buf[0];
718 }
719 } else {
720 // Don't use char_at_addr(0) if length is 0
721 value = (jchar*) s_value->base(T_CHAR);
722 }
723
724 // invoke the callback
725 jint res = (*cb)(wrapper->klass_tag(),
726 wrapper->obj_size(),
727 wrapper->obj_tag_p(),
728 value,
729 (jint)s_len,
730 user_data);
731
732 if (is_latin1 && s_len > 0) {
733 FREE_C_HEAP_ARRAY(jchar, value);
734 }
735 return res;
736 }
737
738 // helper function to invoke string primitive value callback
739 // returns visit control flags
740 static jint invoke_array_primitive_value_callback(jvmtiArrayPrimitiveValueCallback cb,
741 CallbackWrapper* wrapper,
742 oop obj,
743 void* user_data)
744 {
745 assert(obj->is_typeArray(), "not a primitive array");
746
747 // get base address of first element
748 typeArrayOop array = typeArrayOop(obj);
749 BasicType type = TypeArrayKlass::cast(array->klass())->element_type();
750 void* elements = array->base(type);
751
752 // jvmtiPrimitiveType is defined so this mapping is always correct
753 jvmtiPrimitiveType elem_type = (jvmtiPrimitiveType)type2char(type);
754
755 return (*cb)(wrapper->klass_tag(),
756 wrapper->obj_size(),
757 wrapper->obj_tag_p(),
758 (jint)array->length(),
759 elem_type,
760 elements,
761 user_data);
762 }
763
764 // helper function to invoke the primitive field callback for all static fields
765 // of a given class
766 static jint invoke_primitive_field_callback_for_static_fields
767 (CallbackWrapper* wrapper,
768 oop obj,
769 jvmtiPrimitiveFieldCallback cb,
770 void* user_data)
771 {
772 // for static fields only the index will be set
773 static jvmtiHeapReferenceInfo reference_info = { 0 };
774
775 assert(obj->klass() == vmClasses::Class_klass(), "not a class");
776 if (java_lang_Class::is_primitive(obj)) {
777 return 0;
778 }
779 Klass* klass = java_lang_Class::as_Klass(obj);
780
781 // ignore classes for object and type arrays
782 if (!klass->is_instance_klass()) {
783 return 0;
784 }
785
786 // ignore classes which aren't linked yet
787 InstanceKlass* ik = InstanceKlass::cast(klass);
788 if (!ik->is_linked()) {
789 return 0;
790 }
791
792 // get the field map
793 ClassFieldMap* field_map = ClassFieldMap::create_map_of_static_fields(klass);
794
795 // invoke the callback for each static primitive field
796 for (int i=0; i<field_map->field_count(); i++) {
797 ClassFieldDescriptor* field = field_map->field_at(i);
798
799 // ignore non-primitive fields
800 char type = field->field_type();
801 if (!is_primitive_field_type(type)) {
802 continue;
803 }
804 // one-to-one mapping
805 jvmtiPrimitiveType value_type = (jvmtiPrimitiveType)type;
806
807 // get offset and field value
808 int offset = field->field_offset();
809 address addr = cast_from_oop<address>(klass->java_mirror()) + offset;
810 jvalue value;
811 copy_to_jvalue(&value, addr, value_type);
812
813 // field index
814 reference_info.field.index = field->field_index();
815
816 // invoke the callback
817 jint res = (*cb)(JVMTI_HEAP_REFERENCE_STATIC_FIELD,
818 &reference_info,
819 wrapper->klass_tag(),
820 wrapper->obj_tag_p(),
821 value,
822 value_type,
823 user_data);
824 if (res & JVMTI_VISIT_ABORT) {
825 delete field_map;
826 return res;
827 }
828 }
829
830 delete field_map;
831 return 0;
832 }
833
834 // helper function to invoke the primitive field callback for all instance fields
835 // of a given object
836 static jint invoke_primitive_field_callback_for_instance_fields(
837 CallbackWrapper* wrapper,
838 oop obj,
839 jvmtiPrimitiveFieldCallback cb,
840 void* user_data)
841 {
842 // for instance fields only the index will be set
843 static jvmtiHeapReferenceInfo reference_info = { 0 };
844
845 // get the map of the instance fields
846 ClassFieldMap* fields = JvmtiCachedClassFieldMap::get_map_of_instance_fields(obj);
847
848 // invoke the callback for each instance primitive field
849 for (int i=0; i<fields->field_count(); i++) {
850 ClassFieldDescriptor* field = fields->field_at(i);
851
852 // ignore non-primitive fields
853 char type = field->field_type();
854 if (!is_primitive_field_type(type)) {
855 continue;
856 }
857 // one-to-one mapping
858 jvmtiPrimitiveType value_type = (jvmtiPrimitiveType)type;
859
860 // get offset and field value
861 int offset = field->field_offset();
862 address addr = cast_from_oop<address>(obj) + offset;
863 jvalue value;
864 copy_to_jvalue(&value, addr, value_type);
865
866 // field index
867 reference_info.field.index = field->field_index();
868
869 // invoke the callback
870 jint res = (*cb)(JVMTI_HEAP_REFERENCE_FIELD,
871 &reference_info,
872 wrapper->klass_tag(),
873 wrapper->obj_tag_p(),
874 value,
875 value_type,
876 user_data);
877 if (res & JVMTI_VISIT_ABORT) {
878 return res;
879 }
880 }
881 return 0;
882 }
883
884
885 // VM operation to iterate over all objects in the heap (both reachable
886 // and unreachable)
887 class VM_HeapIterateOperation: public VM_Operation {
888 private:
889 ObjectClosure* _blk;
890 GrowableArray<jlong>* const _dead_objects;
891 public:
892 VM_HeapIterateOperation(ObjectClosure* blk, GrowableArray<jlong>* objects) :
893 _blk(blk), _dead_objects(objects) { }
894
895 VMOp_Type type() const { return VMOp_HeapIterateOperation; }
896 void doit() {
897 // allows class files maps to be cached during iteration
898 ClassFieldMapCacheMark cm;
899
900 JvmtiTagMap::check_hashmaps_for_heapwalk(_dead_objects);
901
902 // make sure that heap is parsable (fills TLABs with filler objects)
903 Universe::heap()->ensure_parsability(false); // no need to retire TLABs
904
905 // Verify heap before iteration - if the heap gets corrupted then
906 // JVMTI's IterateOverHeap will crash.
907 if (VerifyBeforeIteration) {
908 Universe::verify();
909 }
910
911 // do the iteration
912 Universe::heap()->object_iterate(_blk);
913 }
914
915 };
916
917
918 // An ObjectClosure used to support the deprecated IterateOverHeap and
919 // IterateOverInstancesOfClass functions
920 class IterateOverHeapObjectClosure: public ObjectClosure {
921 private:
922 JvmtiTagMap* _tag_map;
923 Klass* _klass;
924 jvmtiHeapObjectFilter _object_filter;
925 jvmtiHeapObjectCallback _heap_object_callback;
926 const void* _user_data;
927
928 // accessors
929 JvmtiTagMap* tag_map() const { return _tag_map; }
930 jvmtiHeapObjectFilter object_filter() const { return _object_filter; }
931 jvmtiHeapObjectCallback object_callback() const { return _heap_object_callback; }
932 Klass* klass() const { return _klass; }
933 const void* user_data() const { return _user_data; }
934
935 // indicates if iteration has been aborted
936 bool _iteration_aborted;
937 bool is_iteration_aborted() const { return _iteration_aborted; }
938 void set_iteration_aborted(bool aborted) { _iteration_aborted = aborted; }
939
940 public:
941 IterateOverHeapObjectClosure(JvmtiTagMap* tag_map,
942 Klass* klass,
943 jvmtiHeapObjectFilter object_filter,
944 jvmtiHeapObjectCallback heap_object_callback,
945 const void* user_data) :
946 _tag_map(tag_map),
947 _klass(klass),
948 _object_filter(object_filter),
949 _heap_object_callback(heap_object_callback),
950 _user_data(user_data),
951 _iteration_aborted(false)
952 {
953 }
954
955 void do_object(oop o);
956 };
957
958 // invoked for each object in the heap
959 void IterateOverHeapObjectClosure::do_object(oop o) {
960 // check if iteration has been halted
961 if (is_iteration_aborted()) return;
962
963 // instanceof check when filtering by klass
964 if (klass() != NULL && !o->is_a(klass())) {
965 return;
966 }
967
968 // skip if object is a dormant shared object whose mirror hasn't been loaded
969 if (o != NULL && o->klass()->java_mirror() == NULL) {
970 log_debug(cds, heap)("skipped dormant archived object " INTPTR_FORMAT " (%s)", p2i(o),
971 o->klass()->external_name());
972 return;
973 }
974
975 // prepare for the calllback
976 CallbackWrapper wrapper(tag_map(), o);
977
978 // if the object is tagged and we're only interested in untagged objects
979 // then don't invoke the callback. Similiarly, if the object is untagged
980 // and we're only interested in tagged objects we skip the callback.
981 if (wrapper.obj_tag() != 0) {
982 if (object_filter() == JVMTI_HEAP_OBJECT_UNTAGGED) return;
983 } else {
984 if (object_filter() == JVMTI_HEAP_OBJECT_TAGGED) return;
985 }
986
987 // invoke the agent's callback
988 jvmtiIterationControl control = (*object_callback())(wrapper.klass_tag(),
989 wrapper.obj_size(),
990 wrapper.obj_tag_p(),
991 (void*)user_data());
992 if (control == JVMTI_ITERATION_ABORT) {
993 set_iteration_aborted(true);
994 }
995 }
996
997 // An ObjectClosure used to support the IterateThroughHeap function
998 class IterateThroughHeapObjectClosure: public ObjectClosure {
999 private:
1000 JvmtiTagMap* _tag_map;
1001 Klass* _klass;
1002 int _heap_filter;
1003 const jvmtiHeapCallbacks* _callbacks;
1004 const void* _user_data;
1005
1006 // accessor functions
1007 JvmtiTagMap* tag_map() const { return _tag_map; }
1008 int heap_filter() const { return _heap_filter; }
1009 const jvmtiHeapCallbacks* callbacks() const { return _callbacks; }
1010 Klass* klass() const { return _klass; }
1011 const void* user_data() const { return _user_data; }
1012
1013 // indicates if the iteration has been aborted
1014 bool _iteration_aborted;
1015 bool is_iteration_aborted() const { return _iteration_aborted; }
1016
1017 // used to check the visit control flags. If the abort flag is set
1018 // then we set the iteration aborted flag so that the iteration completes
1019 // without processing any further objects
1020 bool check_flags_for_abort(jint flags) {
1021 bool is_abort = (flags & JVMTI_VISIT_ABORT) != 0;
1022 if (is_abort) {
1023 _iteration_aborted = true;
1024 }
1025 return is_abort;
1026 }
1027
1028 public:
1029 IterateThroughHeapObjectClosure(JvmtiTagMap* tag_map,
1030 Klass* klass,
1031 int heap_filter,
1032 const jvmtiHeapCallbacks* heap_callbacks,
1033 const void* user_data) :
1034 _tag_map(tag_map),
1035 _klass(klass),
1036 _heap_filter(heap_filter),
1037 _callbacks(heap_callbacks),
1038 _user_data(user_data),
1039 _iteration_aborted(false)
1040 {
1041 }
1042
1043 void do_object(oop o);
1044 };
1045
1046 // invoked for each object in the heap
1047 void IterateThroughHeapObjectClosure::do_object(oop obj) {
1048 // check if iteration has been halted
1049 if (is_iteration_aborted()) return;
1050
1051 // apply class filter
1052 if (is_filtered_by_klass_filter(obj, klass())) return;
1053
1054 // skip if object is a dormant shared object whose mirror hasn't been loaded
1055 if (obj != NULL && obj->klass()->java_mirror() == NULL) {
1056 log_debug(cds, heap)("skipped dormant archived object " INTPTR_FORMAT " (%s)", p2i(obj),
1057 obj->klass()->external_name());
1058 return;
1059 }
1060
1061 // prepare for callback
1062 CallbackWrapper wrapper(tag_map(), obj);
1063
1064 // check if filtered by the heap filter
1065 if (is_filtered_by_heap_filter(wrapper.obj_tag(), wrapper.klass_tag(), heap_filter())) {
1066 return;
1067 }
1068
1069 // for arrays we need the length, otherwise -1
1070 bool is_array = obj->is_array();
1071 int len = is_array ? arrayOop(obj)->length() : -1;
1072
1073 // invoke the object callback (if callback is provided)
1074 if (callbacks()->heap_iteration_callback != NULL) {
1075 jvmtiHeapIterationCallback cb = callbacks()->heap_iteration_callback;
1076 jint res = (*cb)(wrapper.klass_tag(),
1077 wrapper.obj_size(),
1078 wrapper.obj_tag_p(),
1079 (jint)len,
1080 (void*)user_data());
1081 if (check_flags_for_abort(res)) return;
1082 }
1083
1084 // for objects and classes we report primitive fields if callback provided
1085 if (callbacks()->primitive_field_callback != NULL && obj->is_instance()) {
1086 jint res;
1087 jvmtiPrimitiveFieldCallback cb = callbacks()->primitive_field_callback;
1088 if (obj->klass() == vmClasses::Class_klass()) {
1089 res = invoke_primitive_field_callback_for_static_fields(&wrapper,
1090 obj,
1091 cb,
1092 (void*)user_data());
1093 } else {
1094 res = invoke_primitive_field_callback_for_instance_fields(&wrapper,
1095 obj,
1096 cb,
1097 (void*)user_data());
1098 }
1099 if (check_flags_for_abort(res)) return;
1100 }
1101
1102 // string callback
1103 if (!is_array &&
1104 callbacks()->string_primitive_value_callback != NULL &&
1105 obj->klass() == vmClasses::String_klass()) {
1106 jint res = invoke_string_value_callback(
1107 callbacks()->string_primitive_value_callback,
1108 &wrapper,
1109 obj,
1110 (void*)user_data() );
1111 if (check_flags_for_abort(res)) return;
1112 }
1113
1114 // array callback
1115 if (is_array &&
1116 callbacks()->array_primitive_value_callback != NULL &&
1117 obj->is_typeArray()) {
1118 jint res = invoke_array_primitive_value_callback(
1119 callbacks()->array_primitive_value_callback,
1120 &wrapper,
1121 obj,
1122 (void*)user_data() );
1123 if (check_flags_for_abort(res)) return;
1124 }
1125 };
1126
1127
1128 // Deprecated function to iterate over all objects in the heap
1129 void JvmtiTagMap::iterate_over_heap(jvmtiHeapObjectFilter object_filter,
1130 Klass* klass,
1131 jvmtiHeapObjectCallback heap_object_callback,
1132 const void* user_data)
1133 {
1134 // EA based optimizations on tagged objects are already reverted.
1135 EscapeBarrier eb(object_filter == JVMTI_HEAP_OBJECT_UNTAGGED ||
1136 object_filter == JVMTI_HEAP_OBJECT_EITHER,
1137 JavaThread::current());
1138 eb.deoptimize_objects_all_threads();
1139 Arena dead_object_arena(mtServiceability);
1140 GrowableArray <jlong> dead_objects(&dead_object_arena, 10, 0, 0);
1141 {
1142 MutexLocker ml(Heap_lock);
1143 IterateOverHeapObjectClosure blk(this,
1144 klass,
1145 object_filter,
1146 heap_object_callback,
1147 user_data);
1148 VM_HeapIterateOperation op(&blk, &dead_objects);
1149 VMThread::execute(&op);
1150 }
1151 // Post events outside of Heap_lock
1152 post_dead_objects(&dead_objects);
1153 }
1154
1155
1156 // Iterates over all objects in the heap
1157 void JvmtiTagMap::iterate_through_heap(jint heap_filter,
1158 Klass* klass,
1159 const jvmtiHeapCallbacks* callbacks,
1160 const void* user_data)
1161 {
1162 // EA based optimizations on tagged objects are already reverted.
1163 EscapeBarrier eb(!(heap_filter & JVMTI_HEAP_FILTER_UNTAGGED), JavaThread::current());
1164 eb.deoptimize_objects_all_threads();
1165
1166 Arena dead_object_arena(mtServiceability);
1167 GrowableArray<jlong> dead_objects(&dead_object_arena, 10, 0, 0);
1168 {
1169 MutexLocker ml(Heap_lock);
1170 IterateThroughHeapObjectClosure blk(this,
1171 klass,
1172 heap_filter,
1173 callbacks,
1174 user_data);
1175 VM_HeapIterateOperation op(&blk, &dead_objects);
1176 VMThread::execute(&op);
1177 }
1178 // Post events outside of Heap_lock
1179 post_dead_objects(&dead_objects);
1180 }
1181
1182 void JvmtiTagMap::remove_dead_entries_locked(GrowableArray<jlong>* objects) {
1183 assert(is_locked(), "precondition");
1184 if (_needs_cleaning) {
1185 // Recheck whether to post object free events under the lock.
1186 if (!env()->is_enabled(JVMTI_EVENT_OBJECT_FREE)) {
1187 objects = NULL;
1188 }
1189 log_info(jvmti, table)("TagMap table needs cleaning%s",
1190 ((objects != NULL) ? " and posting" : ""));
1191 hashmap()->remove_dead_entries(objects);
1192 _needs_cleaning = false;
1193 }
1194 }
1195
1196 void JvmtiTagMap::remove_dead_entries(GrowableArray<jlong>* objects) {
1197 MutexLocker ml(lock(), Mutex::_no_safepoint_check_flag);
1198 remove_dead_entries_locked(objects);
1199 }
1200
1201 void JvmtiTagMap::post_dead_objects(GrowableArray<jlong>* const objects) {
1202 assert(Thread::current()->is_Java_thread(), "Must post from JavaThread");
1203 if (objects != NULL && objects->length() > 0) {
1204 JvmtiExport::post_object_free(env(), objects);
1205 log_info(jvmti)("%d free object posted", objects->length());
1206 }
1207 }
1208
1209 void JvmtiTagMap::remove_and_post_dead_objects() {
1210 ResourceMark rm;
1211 GrowableArray<jlong> objects;
1212 remove_dead_entries(&objects);
1213 post_dead_objects(&objects);
1214 }
1215
1216 void JvmtiTagMap::flush_object_free_events() {
1217 assert_not_at_safepoint();
1218 if (env()->is_enabled(JVMTI_EVENT_OBJECT_FREE)) {
1219 {
1220 MonitorLocker ml(lock(), Mutex::_no_safepoint_check_flag);
1221 // If another thread is posting events, let it finish
1222 while (_posting_events) {
1223 ml.wait();
1224 }
1225
1226 if (!_needs_cleaning || is_empty()) {
1227 _needs_cleaning = false;
1228 return;
1229 }
1230 _posting_events = true;
1231 } // Drop the lock so we can do the cleaning on the VM thread.
1232 // Needs both cleaning and event posting (up to some other thread
1233 // getting there first after we dropped the lock).
1234 remove_and_post_dead_objects();
1235 {
1236 MonitorLocker ml(lock(), Mutex::_no_safepoint_check_flag);
1237 _posting_events = false;
1238 ml.notify_all();
1239 }
1240 } else {
1241 remove_dead_entries(NULL);
1242 }
1243 }
1244
1245 // support class for get_objects_with_tags
1246
1247 class TagObjectCollector : public JvmtiTagMapEntryClosure {
1248 private:
1249 JvmtiEnv* _env;
1250 JavaThread* _thread;
1251 jlong* _tags;
1252 jint _tag_count;
1253 bool _some_dead_found;
1254
1255 GrowableArray<jobject>* _object_results; // collected objects (JNI weak refs)
1256 GrowableArray<uint64_t>* _tag_results; // collected tags
1257
1258 public:
1259 TagObjectCollector(JvmtiEnv* env, const jlong* tags, jint tag_count) :
1260 _env(env),
1261 _thread(JavaThread::current()),
1262 _tags((jlong*)tags),
1263 _tag_count(tag_count),
1264 _some_dead_found(false),
1265 _object_results(new (ResourceObj::C_HEAP, mtServiceability) GrowableArray<jobject>(1, mtServiceability)),
1266 _tag_results(new (ResourceObj::C_HEAP, mtServiceability) GrowableArray<uint64_t>(1, mtServiceability)) { }
1267
1268 ~TagObjectCollector() {
1269 delete _object_results;
1270 delete _tag_results;
1271 }
1272
1273 bool some_dead_found() const { return _some_dead_found; }
1274
1275 // for each tagged object check if the tag value matches
1276 // - if it matches then we create a JNI local reference to the object
1277 // and record the reference and tag value.
1278 //
1279 void do_entry(JvmtiTagMapEntry* entry) {
1280 for (int i=0; i<_tag_count; i++) {
1281 if (_tags[i] == entry->tag()) {
1282 // The reference in this tag map could be the only (implicitly weak)
1283 // reference to that object. If we hand it out, we need to keep it live wrt
1284 // SATB marking similar to other j.l.ref.Reference referents. This is
1285 // achieved by using a phantom load in the object() accessor.
1286 oop o = entry->object();
1287 if (o == NULL) {
1288 _some_dead_found = true;
1289 // skip this whole entry
1290 return;
1291 }
1292 assert(o != NULL && Universe::heap()->is_in(o), "sanity check");
1293 jobject ref = JNIHandles::make_local(_thread, o);
1294 _object_results->append(ref);
1295 _tag_results->append((uint64_t)entry->tag());
1296 }
1297 }
1298 }
1299
1300 // return the results from the collection
1301 //
1302 jvmtiError result(jint* count_ptr, jobject** object_result_ptr, jlong** tag_result_ptr) {
1303 jvmtiError error;
1304 int count = _object_results->length();
1305 assert(count >= 0, "sanity check");
1306
1307 // if object_result_ptr is not NULL then allocate the result and copy
1308 // in the object references.
1309 if (object_result_ptr != NULL) {
1310 error = _env->Allocate(count * sizeof(jobject), (unsigned char**)object_result_ptr);
1311 if (error != JVMTI_ERROR_NONE) {
1312 return error;
1313 }
1314 for (int i=0; i<count; i++) {
1315 (*object_result_ptr)[i] = _object_results->at(i);
1316 }
1317 }
1318
1319 // if tag_result_ptr is not NULL then allocate the result and copy
1320 // in the tag values.
1321 if (tag_result_ptr != NULL) {
1322 error = _env->Allocate(count * sizeof(jlong), (unsigned char**)tag_result_ptr);
1323 if (error != JVMTI_ERROR_NONE) {
1324 if (object_result_ptr != NULL) {
1325 _env->Deallocate((unsigned char*)object_result_ptr);
1326 }
1327 return error;
1328 }
1329 for (int i=0; i<count; i++) {
1330 (*tag_result_ptr)[i] = (jlong)_tag_results->at(i);
1331 }
1332 }
1333
1334 *count_ptr = count;
1335 return JVMTI_ERROR_NONE;
1336 }
1337 };
1338
1339 // return the list of objects with the specified tags
1340 jvmtiError JvmtiTagMap::get_objects_with_tags(const jlong* tags,
1341 jint count, jint* count_ptr, jobject** object_result_ptr, jlong** tag_result_ptr) {
1342
1343 TagObjectCollector collector(env(), tags, count);
1344 {
1345 // iterate over all tagged objects
1346 MutexLocker ml(lock(), Mutex::_no_safepoint_check_flag);
1347 // Can't post ObjectFree events here from a JavaThread, so this
1348 // will race with the gc_notification thread in the tiny
1349 // window where the object is not marked but hasn't been notified that
1350 // it is collected yet.
1351 entry_iterate(&collector);
1352 }
1353 return collector.result(count_ptr, object_result_ptr, tag_result_ptr);
1354 }
1355
1356
1357 // ObjectMarker is used to support the marking objects when walking the
1358 // heap.
1359 //
1360 // This implementation uses the existing mark bits in an object for
1361 // marking. Objects that are marked must later have their headers restored.
1362 // As most objects are unlocked and don't have their identity hash computed
1363 // we don't have to save their headers. Instead we save the headers that
1364 // are "interesting". Later when the headers are restored this implementation
1365 // restores all headers to their initial value and then restores the few
1366 // objects that had interesting headers.
1367 //
1368 // Future work: This implementation currently uses growable arrays to save
1369 // the oop and header of interesting objects. As an optimization we could
1370 // use the same technique as the GC and make use of the unused area
1371 // between top() and end().
1372 //
1373
1374 // An ObjectClosure used to restore the mark bits of an object
1375 class RestoreMarksClosure : public ObjectClosure {
1376 public:
1377 void do_object(oop o) {
1378 if (o != NULL) {
1379 markWord mark = o->mark();
1380 if (mark.is_marked()) {
1381 o->init_mark();
1382 }
1383 }
1384 }
1385 };
1386
1387 // ObjectMarker provides the mark and visited functions
1388 class ObjectMarker : AllStatic {
1389 private:
1390 // saved headers
1391 static GrowableArray<oop>* _saved_oop_stack;
1392 static GrowableArray<markWord>* _saved_mark_stack;
1393 static bool _needs_reset; // do we need to reset mark bits?
1394
1395 public:
1396 static void init(); // initialize
1397 static void done(); // clean-up
1398
1399 static inline void mark(oop o); // mark an object
1400 static inline bool visited(oop o); // check if object has been visited
1401
1402 static inline bool needs_reset() { return _needs_reset; }
1403 static inline void set_needs_reset(bool v) { _needs_reset = v; }
1404 };
1405
1406 GrowableArray<oop>* ObjectMarker::_saved_oop_stack = NULL;
1407 GrowableArray<markWord>* ObjectMarker::_saved_mark_stack = NULL;
1408 bool ObjectMarker::_needs_reset = true; // need to reset mark bits by default
1409
1410 // initialize ObjectMarker - prepares for object marking
1411 void ObjectMarker::init() {
1412 assert(Thread::current()->is_VM_thread(), "must be VMThread");
1413 assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint");
1414
1415 // prepare heap for iteration
1416 Universe::heap()->ensure_parsability(false); // no need to retire TLABs
1417
1418 // create stacks for interesting headers
1419 _saved_mark_stack = new (ResourceObj::C_HEAP, mtServiceability) GrowableArray<markWord>(4000, mtServiceability);
1420 _saved_oop_stack = new (ResourceObj::C_HEAP, mtServiceability) GrowableArray<oop>(4000, mtServiceability);
1421
1422 if (UseBiasedLocking) {
1423 BiasedLocking::preserve_marks();
1424 }
1425 }
1426
1427 // Object marking is done so restore object headers
1428 void ObjectMarker::done() {
1429 // iterate over all objects and restore the mark bits to
1430 // their initial value
1431 RestoreMarksClosure blk;
1432 if (needs_reset()) {
1433 Universe::heap()->object_iterate(&blk);
1434 } else {
1435 // We don't need to reset mark bits on this call, but reset the
1436 // flag to the default for the next call.
1437 set_needs_reset(true);
1438 }
1439
1440 // now restore the interesting headers
1441 for (int i = 0; i < _saved_oop_stack->length(); i++) {
1442 oop o = _saved_oop_stack->at(i);
1443 markWord mark = _saved_mark_stack->at(i);
1444 o->set_mark(mark);
1445 }
1446
1447 if (UseBiasedLocking) {
1448 BiasedLocking::restore_marks();
1449 }
1450
1451 // free the stacks
1452 delete _saved_oop_stack;
1453 delete _saved_mark_stack;
1454 }
1455
1456 // mark an object
1457 inline void ObjectMarker::mark(oop o) {
1458 assert(Universe::heap()->is_in(o), "sanity check");
1459 assert(!o->mark().is_marked(), "should only mark an object once");
1460
1461 // object's mark word
1462 markWord mark = o->mark();
1463
1464 if (o->mark_must_be_preserved(mark)) {
1465 _saved_mark_stack->push(mark);
1466 _saved_oop_stack->push(o);
1467 }
1468
1469 // mark the object
1470 o->set_mark(markWord::prototype().set_marked());
1471 }
1472
1473 // return true if object is marked
1474 inline bool ObjectMarker::visited(oop o) {
1475 return o->mark().is_marked();
1476 }
1477
1478 // Stack allocated class to help ensure that ObjectMarker is used
1479 // correctly. Constructor initializes ObjectMarker, destructor calls
1480 // ObjectMarker's done() function to restore object headers.
1481 class ObjectMarkerController : public StackObj {
1482 public:
1483 ObjectMarkerController() {
1484 ObjectMarker::init();
1485 }
1486 ~ObjectMarkerController() {
1487 ObjectMarker::done();
1488 }
1489 };
1490
1491
1492 // helper to map a jvmtiHeapReferenceKind to an old style jvmtiHeapRootKind
1493 // (not performance critical as only used for roots)
1494 static jvmtiHeapRootKind toJvmtiHeapRootKind(jvmtiHeapReferenceKind kind) {
1495 switch (kind) {
1496 case JVMTI_HEAP_REFERENCE_JNI_GLOBAL: return JVMTI_HEAP_ROOT_JNI_GLOBAL;
1497 case JVMTI_HEAP_REFERENCE_SYSTEM_CLASS: return JVMTI_HEAP_ROOT_SYSTEM_CLASS;
1498 case JVMTI_HEAP_REFERENCE_STACK_LOCAL: return JVMTI_HEAP_ROOT_STACK_LOCAL;
1499 case JVMTI_HEAP_REFERENCE_JNI_LOCAL: return JVMTI_HEAP_ROOT_JNI_LOCAL;
1500 case JVMTI_HEAP_REFERENCE_THREAD: return JVMTI_HEAP_ROOT_THREAD;
1501 case JVMTI_HEAP_REFERENCE_OTHER: return JVMTI_HEAP_ROOT_OTHER;
1502 default: ShouldNotReachHere(); return JVMTI_HEAP_ROOT_OTHER;
1503 }
1504 }
1505
1506 // Base class for all heap walk contexts. The base class maintains a flag
1507 // to indicate if the context is valid or not.
1508 class HeapWalkContext {
1509 private:
1510 bool _valid;
1511 public:
1512 HeapWalkContext(bool valid) { _valid = valid; }
1513 void invalidate() { _valid = false; }
1514 bool is_valid() const { return _valid; }
1515 };
1516
1517 // A basic heap walk context for the deprecated heap walking functions.
1518 // The context for a basic heap walk are the callbacks and fields used by
1519 // the referrer caching scheme.
1520 class BasicHeapWalkContext: public HeapWalkContext {
1521 private:
1522 jvmtiHeapRootCallback _heap_root_callback;
1523 jvmtiStackReferenceCallback _stack_ref_callback;
1524 jvmtiObjectReferenceCallback _object_ref_callback;
1525
1526 // used for caching
1527 oop _last_referrer;
1528 jlong _last_referrer_tag;
1529
1530 public:
1531 BasicHeapWalkContext() : HeapWalkContext(false) { }
1532
1533 BasicHeapWalkContext(jvmtiHeapRootCallback heap_root_callback,
1534 jvmtiStackReferenceCallback stack_ref_callback,
1535 jvmtiObjectReferenceCallback object_ref_callback) :
1536 HeapWalkContext(true),
1537 _heap_root_callback(heap_root_callback),
1538 _stack_ref_callback(stack_ref_callback),
1539 _object_ref_callback(object_ref_callback),
1540 _last_referrer(NULL),
1541 _last_referrer_tag(0) {
1542 }
1543
1544 // accessors
1545 jvmtiHeapRootCallback heap_root_callback() const { return _heap_root_callback; }
1546 jvmtiStackReferenceCallback stack_ref_callback() const { return _stack_ref_callback; }
1547 jvmtiObjectReferenceCallback object_ref_callback() const { return _object_ref_callback; }
1548
1549 oop last_referrer() const { return _last_referrer; }
1550 void set_last_referrer(oop referrer) { _last_referrer = referrer; }
1551 jlong last_referrer_tag() const { return _last_referrer_tag; }
1552 void set_last_referrer_tag(jlong value) { _last_referrer_tag = value; }
1553 };
1554
1555 // The advanced heap walk context for the FollowReferences functions.
1556 // The context is the callbacks, and the fields used for filtering.
1557 class AdvancedHeapWalkContext: public HeapWalkContext {
1558 private:
1559 jint _heap_filter;
1560 Klass* _klass_filter;
1561 const jvmtiHeapCallbacks* _heap_callbacks;
1562
1563 public:
1564 AdvancedHeapWalkContext() : HeapWalkContext(false) { }
1565
1566 AdvancedHeapWalkContext(jint heap_filter,
1567 Klass* klass_filter,
1568 const jvmtiHeapCallbacks* heap_callbacks) :
1569 HeapWalkContext(true),
1570 _heap_filter(heap_filter),
1571 _klass_filter(klass_filter),
1572 _heap_callbacks(heap_callbacks) {
1573 }
1574
1575 // accessors
1576 jint heap_filter() const { return _heap_filter; }
1577 Klass* klass_filter() const { return _klass_filter; }
1578
1579 const jvmtiHeapReferenceCallback heap_reference_callback() const {
1580 return _heap_callbacks->heap_reference_callback;
1581 };
1582 const jvmtiPrimitiveFieldCallback primitive_field_callback() const {
1583 return _heap_callbacks->primitive_field_callback;
1584 }
1585 const jvmtiArrayPrimitiveValueCallback array_primitive_value_callback() const {
1586 return _heap_callbacks->array_primitive_value_callback;
1587 }
1588 const jvmtiStringPrimitiveValueCallback string_primitive_value_callback() const {
1589 return _heap_callbacks->string_primitive_value_callback;
1590 }
1591 };
1592
1593 // The CallbackInvoker is a class with static functions that the heap walk can call
1594 // into to invoke callbacks. It works in one of two modes. The "basic" mode is
1595 // used for the deprecated IterateOverReachableObjects functions. The "advanced"
1596 // mode is for the newer FollowReferences function which supports a lot of
1597 // additional callbacks.
1598 class CallbackInvoker : AllStatic {
1599 private:
1600 // heap walk styles
1601 enum { basic, advanced };
1602 static int _heap_walk_type;
1603 static bool is_basic_heap_walk() { return _heap_walk_type == basic; }
1604 static bool is_advanced_heap_walk() { return _heap_walk_type == advanced; }
1605
1606 // context for basic style heap walk
1607 static BasicHeapWalkContext _basic_context;
1608 static BasicHeapWalkContext* basic_context() {
1609 assert(_basic_context.is_valid(), "invalid");
1610 return &_basic_context;
1611 }
1612
1613 // context for advanced style heap walk
1614 static AdvancedHeapWalkContext _advanced_context;
1615 static AdvancedHeapWalkContext* advanced_context() {
1616 assert(_advanced_context.is_valid(), "invalid");
1617 return &_advanced_context;
1618 }
1619
1620 // context needed for all heap walks
1621 static JvmtiTagMap* _tag_map;
1622 static const void* _user_data;
1623 static GrowableArray<oop>* _visit_stack;
1624
1625 // accessors
1626 static JvmtiTagMap* tag_map() { return _tag_map; }
1627 static const void* user_data() { return _user_data; }
1628 static GrowableArray<oop>* visit_stack() { return _visit_stack; }
1629
1630 // if the object hasn't been visited then push it onto the visit stack
1631 // so that it will be visited later
1632 static inline bool check_for_visit(oop obj) {
1633 if (!ObjectMarker::visited(obj)) visit_stack()->push(obj);
1634 return true;
1635 }
1636
1637 // invoke basic style callbacks
1638 static inline bool invoke_basic_heap_root_callback
1639 (jvmtiHeapRootKind root_kind, oop obj);
1640 static inline bool invoke_basic_stack_ref_callback
1641 (jvmtiHeapRootKind root_kind, jlong thread_tag, jint depth, jmethodID method,
1642 int slot, oop obj);
1643 static inline bool invoke_basic_object_reference_callback
1644 (jvmtiObjectReferenceKind ref_kind, oop referrer, oop referree, jint index);
1645
1646 // invoke advanced style callbacks
1647 static inline bool invoke_advanced_heap_root_callback
1648 (jvmtiHeapReferenceKind ref_kind, oop obj);
1649 static inline bool invoke_advanced_stack_ref_callback
1650 (jvmtiHeapReferenceKind ref_kind, jlong thread_tag, jlong tid, int depth,
1651 jmethodID method, jlocation bci, jint slot, oop obj);
1652 static inline bool invoke_advanced_object_reference_callback
1653 (jvmtiHeapReferenceKind ref_kind, oop referrer, oop referree, jint index);
1654
1655 // used to report the value of primitive fields
1656 static inline bool report_primitive_field
1657 (jvmtiHeapReferenceKind ref_kind, oop obj, jint index, address addr, char type);
1658
1659 public:
1660 // initialize for basic mode
1661 static void initialize_for_basic_heap_walk(JvmtiTagMap* tag_map,
1662 GrowableArray<oop>* visit_stack,
1663 const void* user_data,
1664 BasicHeapWalkContext context);
1665
1666 // initialize for advanced mode
1667 static void initialize_for_advanced_heap_walk(JvmtiTagMap* tag_map,
1668 GrowableArray<oop>* visit_stack,
1669 const void* user_data,
1670 AdvancedHeapWalkContext context);
1671
1672 // functions to report roots
1673 static inline bool report_simple_root(jvmtiHeapReferenceKind kind, oop o);
1674 static inline bool report_jni_local_root(jlong thread_tag, jlong tid, jint depth,
1675 jmethodID m, oop o);
1676 static inline bool report_stack_ref_root(jlong thread_tag, jlong tid, jint depth,
1677 jmethodID method, jlocation bci, jint slot, oop o);
1678
1679 // functions to report references
1680 static inline bool report_array_element_reference(oop referrer, oop referree, jint index);
1681 static inline bool report_class_reference(oop referrer, oop referree);
1682 static inline bool report_class_loader_reference(oop referrer, oop referree);
1683 static inline bool report_signers_reference(oop referrer, oop referree);
1684 static inline bool report_protection_domain_reference(oop referrer, oop referree);
1685 static inline bool report_superclass_reference(oop referrer, oop referree);
1686 static inline bool report_interface_reference(oop referrer, oop referree);
1687 static inline bool report_static_field_reference(oop referrer, oop referree, jint slot);
1688 static inline bool report_field_reference(oop referrer, oop referree, jint slot);
1689 static inline bool report_constant_pool_reference(oop referrer, oop referree, jint index);
1690 static inline bool report_primitive_array_values(oop array);
1691 static inline bool report_string_value(oop str);
1692 static inline bool report_primitive_instance_field(oop o, jint index, address value, char type);
1693 static inline bool report_primitive_static_field(oop o, jint index, address value, char type);
1694 };
1695
1696 // statics
1697 int CallbackInvoker::_heap_walk_type;
1698 BasicHeapWalkContext CallbackInvoker::_basic_context;
1699 AdvancedHeapWalkContext CallbackInvoker::_advanced_context;
1700 JvmtiTagMap* CallbackInvoker::_tag_map;
1701 const void* CallbackInvoker::_user_data;
1702 GrowableArray<oop>* CallbackInvoker::_visit_stack;
1703
1704 // initialize for basic heap walk (IterateOverReachableObjects et al)
1705 void CallbackInvoker::initialize_for_basic_heap_walk(JvmtiTagMap* tag_map,
1706 GrowableArray<oop>* visit_stack,
1707 const void* user_data,
1708 BasicHeapWalkContext context) {
1709 _tag_map = tag_map;
1710 _visit_stack = visit_stack;
1711 _user_data = user_data;
1712 _basic_context = context;
1713 _advanced_context.invalidate(); // will trigger assertion if used
1714 _heap_walk_type = basic;
1715 }
1716
1717 // initialize for advanced heap walk (FollowReferences)
1718 void CallbackInvoker::initialize_for_advanced_heap_walk(JvmtiTagMap* tag_map,
1719 GrowableArray<oop>* visit_stack,
1720 const void* user_data,
1721 AdvancedHeapWalkContext context) {
1722 _tag_map = tag_map;
1723 _visit_stack = visit_stack;
1724 _user_data = user_data;
1725 _advanced_context = context;
1726 _basic_context.invalidate(); // will trigger assertion if used
1727 _heap_walk_type = advanced;
1728 }
1729
1730
1731 // invoke basic style heap root callback
1732 inline bool CallbackInvoker::invoke_basic_heap_root_callback(jvmtiHeapRootKind root_kind, oop obj) {
1733 // if we heap roots should be reported
1734 jvmtiHeapRootCallback cb = basic_context()->heap_root_callback();
1735 if (cb == NULL) {
1736 return check_for_visit(obj);
1737 }
1738
1739 CallbackWrapper wrapper(tag_map(), obj);
1740 jvmtiIterationControl control = (*cb)(root_kind,
1741 wrapper.klass_tag(),
1742 wrapper.obj_size(),
1743 wrapper.obj_tag_p(),
1744 (void*)user_data());
1745 // push root to visit stack when following references
1746 if (control == JVMTI_ITERATION_CONTINUE &&
1747 basic_context()->object_ref_callback() != NULL) {
1748 visit_stack()->push(obj);
1749 }
1750 return control != JVMTI_ITERATION_ABORT;
1751 }
1752
1753 // invoke basic style stack ref callback
1754 inline bool CallbackInvoker::invoke_basic_stack_ref_callback(jvmtiHeapRootKind root_kind,
1755 jlong thread_tag,
1756 jint depth,
1757 jmethodID method,
1758 int slot,
1759 oop obj) {
1760 // if we stack refs should be reported
1761 jvmtiStackReferenceCallback cb = basic_context()->stack_ref_callback();
1762 if (cb == NULL) {
1763 return check_for_visit(obj);
1764 }
1765
1766 CallbackWrapper wrapper(tag_map(), obj);
1767 jvmtiIterationControl control = (*cb)(root_kind,
1768 wrapper.klass_tag(),
1769 wrapper.obj_size(),
1770 wrapper.obj_tag_p(),
1771 thread_tag,
1772 depth,
1773 method,
1774 slot,
1775 (void*)user_data());
1776 // push root to visit stack when following references
1777 if (control == JVMTI_ITERATION_CONTINUE &&
1778 basic_context()->object_ref_callback() != NULL) {
1779 visit_stack()->push(obj);
1780 }
1781 return control != JVMTI_ITERATION_ABORT;
1782 }
1783
1784 // invoke basic style object reference callback
1785 inline bool CallbackInvoker::invoke_basic_object_reference_callback(jvmtiObjectReferenceKind ref_kind,
1786 oop referrer,
1787 oop referree,
1788 jint index) {
1789
1790 BasicHeapWalkContext* context = basic_context();
1791
1792 // callback requires the referrer's tag. If it's the same referrer
1793 // as the last call then we use the cached value.
1794 jlong referrer_tag;
1795 if (referrer == context->last_referrer()) {
1796 referrer_tag = context->last_referrer_tag();
1797 } else {
1798 referrer_tag = tag_for(tag_map(), referrer);
1799 }
1800
1801 // do the callback
1802 CallbackWrapper wrapper(tag_map(), referree);
1803 jvmtiObjectReferenceCallback cb = context->object_ref_callback();
1804 jvmtiIterationControl control = (*cb)(ref_kind,
1805 wrapper.klass_tag(),
1806 wrapper.obj_size(),
1807 wrapper.obj_tag_p(),
1808 referrer_tag,
1809 index,
1810 (void*)user_data());
1811
1812 // record referrer and referrer tag. For self-references record the
1813 // tag value from the callback as this might differ from referrer_tag.
1814 context->set_last_referrer(referrer);
1815 if (referrer == referree) {
1816 context->set_last_referrer_tag(*wrapper.obj_tag_p());
1817 } else {
1818 context->set_last_referrer_tag(referrer_tag);
1819 }
1820
1821 if (control == JVMTI_ITERATION_CONTINUE) {
1822 return check_for_visit(referree);
1823 } else {
1824 return control != JVMTI_ITERATION_ABORT;
1825 }
1826 }
1827
1828 // invoke advanced style heap root callback
1829 inline bool CallbackInvoker::invoke_advanced_heap_root_callback(jvmtiHeapReferenceKind ref_kind,
1830 oop obj) {
1831 AdvancedHeapWalkContext* context = advanced_context();
1832
1833 // check that callback is provided
1834 jvmtiHeapReferenceCallback cb = context->heap_reference_callback();
1835 if (cb == NULL) {
1836 return check_for_visit(obj);
1837 }
1838
1839 // apply class filter
1840 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
1841 return check_for_visit(obj);
1842 }
1843
1844 // setup the callback wrapper
1845 CallbackWrapper wrapper(tag_map(), obj);
1846
1847 // apply tag filter
1848 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
1849 wrapper.klass_tag(),
1850 context->heap_filter())) {
1851 return check_for_visit(obj);
1852 }
1853
1854 // for arrays we need the length, otherwise -1
1855 jint len = (jint)(obj->is_array() ? arrayOop(obj)->length() : -1);
1856
1857 // invoke the callback
1858 jint res = (*cb)(ref_kind,
1859 NULL, // referrer info
1860 wrapper.klass_tag(),
1861 0, // referrer_class_tag is 0 for heap root
1862 wrapper.obj_size(),
1863 wrapper.obj_tag_p(),
1864 NULL, // referrer_tag_p
1865 len,
1866 (void*)user_data());
1867 if (res & JVMTI_VISIT_ABORT) {
1868 return false;// referrer class tag
1869 }
1870 if (res & JVMTI_VISIT_OBJECTS) {
1871 check_for_visit(obj);
1872 }
1873 return true;
1874 }
1875
1876 // report a reference from a thread stack to an object
1877 inline bool CallbackInvoker::invoke_advanced_stack_ref_callback(jvmtiHeapReferenceKind ref_kind,
1878 jlong thread_tag,
1879 jlong tid,
1880 int depth,
1881 jmethodID method,
1882 jlocation bci,
1883 jint slot,
1884 oop obj) {
1885 AdvancedHeapWalkContext* context = advanced_context();
1886
1887 // check that callback is provider
1888 jvmtiHeapReferenceCallback cb = context->heap_reference_callback();
1889 if (cb == NULL) {
1890 return check_for_visit(obj);
1891 }
1892
1893 // apply class filter
1894 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
1895 return check_for_visit(obj);
1896 }
1897
1898 // setup the callback wrapper
1899 CallbackWrapper wrapper(tag_map(), obj);
1900
1901 // apply tag filter
1902 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
1903 wrapper.klass_tag(),
1904 context->heap_filter())) {
1905 return check_for_visit(obj);
1906 }
1907
1908 // setup the referrer info
1909 jvmtiHeapReferenceInfo reference_info;
1910 reference_info.stack_local.thread_tag = thread_tag;
1911 reference_info.stack_local.thread_id = tid;
1912 reference_info.stack_local.depth = depth;
1913 reference_info.stack_local.method = method;
1914 reference_info.stack_local.location = bci;
1915 reference_info.stack_local.slot = slot;
1916
1917 // for arrays we need the length, otherwise -1
1918 jint len = (jint)(obj->is_array() ? arrayOop(obj)->length() : -1);
1919
1920 // call into the agent
1921 int res = (*cb)(ref_kind,
1922 &reference_info,
1923 wrapper.klass_tag(),
1924 0, // referrer_class_tag is 0 for heap root (stack)
1925 wrapper.obj_size(),
1926 wrapper.obj_tag_p(),
1927 NULL, // referrer_tag is 0 for root
1928 len,
1929 (void*)user_data());
1930
1931 if (res & JVMTI_VISIT_ABORT) {
1932 return false;
1933 }
1934 if (res & JVMTI_VISIT_OBJECTS) {
1935 check_for_visit(obj);
1936 }
1937 return true;
1938 }
1939
1940 // This mask is used to pass reference_info to a jvmtiHeapReferenceCallback
1941 // only for ref_kinds defined by the JVM TI spec. Otherwise, NULL is passed.
1942 #define REF_INFO_MASK ((1 << JVMTI_HEAP_REFERENCE_FIELD) \
1943 | (1 << JVMTI_HEAP_REFERENCE_STATIC_FIELD) \
1944 | (1 << JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT) \
1945 | (1 << JVMTI_HEAP_REFERENCE_CONSTANT_POOL) \
1946 | (1 << JVMTI_HEAP_REFERENCE_STACK_LOCAL) \
1947 | (1 << JVMTI_HEAP_REFERENCE_JNI_LOCAL))
1948
1949 // invoke the object reference callback to report a reference
1950 inline bool CallbackInvoker::invoke_advanced_object_reference_callback(jvmtiHeapReferenceKind ref_kind,
1951 oop referrer,
1952 oop obj,
1953 jint index)
1954 {
1955 // field index is only valid field in reference_info
1956 static jvmtiHeapReferenceInfo reference_info = { 0 };
1957
1958 AdvancedHeapWalkContext* context = advanced_context();
1959
1960 // check that callback is provider
1961 jvmtiHeapReferenceCallback cb = context->heap_reference_callback();
1962 if (cb == NULL) {
1963 return check_for_visit(obj);
1964 }
1965
1966 // apply class filter
1967 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
1968 return check_for_visit(obj);
1969 }
1970
1971 // setup the callback wrapper
1972 TwoOopCallbackWrapper wrapper(tag_map(), referrer, obj);
1973
1974 // apply tag filter
1975 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
1976 wrapper.klass_tag(),
1977 context->heap_filter())) {
1978 return check_for_visit(obj);
1979 }
1980
1981 // field index is only valid field in reference_info
1982 reference_info.field.index = index;
1983
1984 // for arrays we need the length, otherwise -1
1985 jint len = (jint)(obj->is_array() ? arrayOop(obj)->length() : -1);
1986
1987 // invoke the callback
1988 int res = (*cb)(ref_kind,
1989 (REF_INFO_MASK & (1 << ref_kind)) ? &reference_info : NULL,
1990 wrapper.klass_tag(),
1991 wrapper.referrer_klass_tag(),
1992 wrapper.obj_size(),
1993 wrapper.obj_tag_p(),
1994 wrapper.referrer_tag_p(),
1995 len,
1996 (void*)user_data());
1997
1998 if (res & JVMTI_VISIT_ABORT) {
1999 return false;
2000 }
2001 if (res & JVMTI_VISIT_OBJECTS) {
2002 check_for_visit(obj);
2003 }
2004 return true;
2005 }
2006
2007 // report a "simple root"
2008 inline bool CallbackInvoker::report_simple_root(jvmtiHeapReferenceKind kind, oop obj) {
2009 assert(kind != JVMTI_HEAP_REFERENCE_STACK_LOCAL &&
2010 kind != JVMTI_HEAP_REFERENCE_JNI_LOCAL, "not a simple root");
2011
2012 if (is_basic_heap_walk()) {
2013 // map to old style root kind
2014 jvmtiHeapRootKind root_kind = toJvmtiHeapRootKind(kind);
2015 return invoke_basic_heap_root_callback(root_kind, obj);
2016 } else {
2017 assert(is_advanced_heap_walk(), "wrong heap walk type");
2018 return invoke_advanced_heap_root_callback(kind, obj);
2019 }
2020 }
2021
2022
2023 // invoke the primitive array values
2024 inline bool CallbackInvoker::report_primitive_array_values(oop obj) {
2025 assert(obj->is_typeArray(), "not a primitive array");
2026
2027 AdvancedHeapWalkContext* context = advanced_context();
2028 assert(context->array_primitive_value_callback() != NULL, "no callback");
2029
2030 // apply class filter
2031 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
2032 return true;
2033 }
2034
2035 CallbackWrapper wrapper(tag_map(), obj);
2036
2037 // apply tag filter
2038 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2039 wrapper.klass_tag(),
2040 context->heap_filter())) {
2041 return true;
2042 }
2043
2044 // invoke the callback
2045 int res = invoke_array_primitive_value_callback(context->array_primitive_value_callback(),
2046 &wrapper,
2047 obj,
2048 (void*)user_data());
2049 return (!(res & JVMTI_VISIT_ABORT));
2050 }
2051
2052 // invoke the string value callback
2053 inline bool CallbackInvoker::report_string_value(oop str) {
2054 assert(str->klass() == vmClasses::String_klass(), "not a string");
2055
2056 AdvancedHeapWalkContext* context = advanced_context();
2057 assert(context->string_primitive_value_callback() != NULL, "no callback");
2058
2059 // apply class filter
2060 if (is_filtered_by_klass_filter(str, context->klass_filter())) {
2061 return true;
2062 }
2063
2064 CallbackWrapper wrapper(tag_map(), str);
2065
2066 // apply tag filter
2067 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2068 wrapper.klass_tag(),
2069 context->heap_filter())) {
2070 return true;
2071 }
2072
2073 // invoke the callback
2074 int res = invoke_string_value_callback(context->string_primitive_value_callback(),
2075 &wrapper,
2076 str,
2077 (void*)user_data());
2078 return (!(res & JVMTI_VISIT_ABORT));
2079 }
2080
2081 // invoke the primitive field callback
2082 inline bool CallbackInvoker::report_primitive_field(jvmtiHeapReferenceKind ref_kind,
2083 oop obj,
2084 jint index,
2085 address addr,
2086 char type)
2087 {
2088 // for primitive fields only the index will be set
2089 static jvmtiHeapReferenceInfo reference_info = { 0 };
2090
2091 AdvancedHeapWalkContext* context = advanced_context();
2092 assert(context->primitive_field_callback() != NULL, "no callback");
2093
2094 // apply class filter
2095 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
2096 return true;
2097 }
2098
2099 CallbackWrapper wrapper(tag_map(), obj);
2100
2101 // apply tag filter
2102 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2103 wrapper.klass_tag(),
2104 context->heap_filter())) {
2105 return true;
2106 }
2107
2108 // the field index in the referrer
2109 reference_info.field.index = index;
2110
2111 // map the type
2112 jvmtiPrimitiveType value_type = (jvmtiPrimitiveType)type;
2113
2114 // setup the jvalue
2115 jvalue value;
2116 copy_to_jvalue(&value, addr, value_type);
2117
2118 jvmtiPrimitiveFieldCallback cb = context->primitive_field_callback();
2119 int res = (*cb)(ref_kind,
2120 &reference_info,
2121 wrapper.klass_tag(),
2122 wrapper.obj_tag_p(),
2123 value,
2124 value_type,
2125 (void*)user_data());
2126 return (!(res & JVMTI_VISIT_ABORT));
2127 }
2128
2129
2130 // instance field
2131 inline bool CallbackInvoker::report_primitive_instance_field(oop obj,
2132 jint index,
2133 address value,
2134 char type) {
2135 return report_primitive_field(JVMTI_HEAP_REFERENCE_FIELD,
2136 obj,
2137 index,
2138 value,
2139 type);
2140 }
2141
2142 // static field
2143 inline bool CallbackInvoker::report_primitive_static_field(oop obj,
2144 jint index,
2145 address value,
2146 char type) {
2147 return report_primitive_field(JVMTI_HEAP_REFERENCE_STATIC_FIELD,
2148 obj,
2149 index,
2150 value,
2151 type);
2152 }
2153
2154 // report a JNI local (root object) to the profiler
2155 inline bool CallbackInvoker::report_jni_local_root(jlong thread_tag, jlong tid, jint depth, jmethodID m, oop obj) {
2156 if (is_basic_heap_walk()) {
2157 return invoke_basic_stack_ref_callback(JVMTI_HEAP_ROOT_JNI_LOCAL,
2158 thread_tag,
2159 depth,
2160 m,
2161 -1,
2162 obj);
2163 } else {
2164 return invoke_advanced_stack_ref_callback(JVMTI_HEAP_REFERENCE_JNI_LOCAL,
2165 thread_tag, tid,
2166 depth,
2167 m,
2168 (jlocation)-1,
2169 -1,
2170 obj);
2171 }
2172 }
2173
2174
2175 // report a local (stack reference, root object)
2176 inline bool CallbackInvoker::report_stack_ref_root(jlong thread_tag,
2177 jlong tid,
2178 jint depth,
2179 jmethodID method,
2180 jlocation bci,
2181 jint slot,
2182 oop obj) {
2183 if (is_basic_heap_walk()) {
2184 return invoke_basic_stack_ref_callback(JVMTI_HEAP_ROOT_STACK_LOCAL,
2185 thread_tag,
2186 depth,
2187 method,
2188 slot,
2189 obj);
2190 } else {
2191 return invoke_advanced_stack_ref_callback(JVMTI_HEAP_REFERENCE_STACK_LOCAL,
2192 thread_tag,
2193 tid,
2194 depth,
2195 method,
2196 bci,
2197 slot,
2198 obj);
2199 }
2200 }
2201
2202 // report an object referencing a class.
2203 inline bool CallbackInvoker::report_class_reference(oop referrer, oop referree) {
2204 if (is_basic_heap_walk()) {
2205 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CLASS, referrer, referree, -1);
2206 } else {
2207 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_CLASS, referrer, referree, -1);
2208 }
2209 }
2210
2211 // report a class referencing its class loader.
2212 inline bool CallbackInvoker::report_class_loader_reference(oop referrer, oop referree) {
2213 if (is_basic_heap_walk()) {
2214 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CLASS_LOADER, referrer, referree, -1);
2215 } else {
2216 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_CLASS_LOADER, referrer, referree, -1);
2217 }
2218 }
2219
2220 // report a class referencing its signers.
2221 inline bool CallbackInvoker::report_signers_reference(oop referrer, oop referree) {
2222 if (is_basic_heap_walk()) {
2223 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_SIGNERS, referrer, referree, -1);
2224 } else {
2225 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_SIGNERS, referrer, referree, -1);
2226 }
2227 }
2228
2229 // report a class referencing its protection domain..
2230 inline bool CallbackInvoker::report_protection_domain_reference(oop referrer, oop referree) {
2231 if (is_basic_heap_walk()) {
2232 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_PROTECTION_DOMAIN, referrer, referree, -1);
2233 } else {
2234 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_PROTECTION_DOMAIN, referrer, referree, -1);
2235 }
2236 }
2237
2238 // report a class referencing its superclass.
2239 inline bool CallbackInvoker::report_superclass_reference(oop referrer, oop referree) {
2240 if (is_basic_heap_walk()) {
2241 // Send this to be consistent with past implementation
2242 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CLASS, referrer, referree, -1);
2243 } else {
2244 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_SUPERCLASS, referrer, referree, -1);
2245 }
2246 }
2247
2248 // report a class referencing one of its interfaces.
2249 inline bool CallbackInvoker::report_interface_reference(oop referrer, oop referree) {
2250 if (is_basic_heap_walk()) {
2251 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_INTERFACE, referrer, referree, -1);
2252 } else {
2253 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_INTERFACE, referrer, referree, -1);
2254 }
2255 }
2256
2257 // report a class referencing one of its static fields.
2258 inline bool CallbackInvoker::report_static_field_reference(oop referrer, oop referree, jint slot) {
2259 if (is_basic_heap_walk()) {
2260 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_STATIC_FIELD, referrer, referree, slot);
2261 } else {
2262 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_STATIC_FIELD, referrer, referree, slot);
2263 }
2264 }
2265
2266 // report an array referencing an element object
2267 inline bool CallbackInvoker::report_array_element_reference(oop referrer, oop referree, jint index) {
2268 if (is_basic_heap_walk()) {
2269 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_ARRAY_ELEMENT, referrer, referree, index);
2270 } else {
2271 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT, referrer, referree, index);
2272 }
2273 }
2274
2275 // report an object referencing an instance field object
2276 inline bool CallbackInvoker::report_field_reference(oop referrer, oop referree, jint slot) {
2277 if (is_basic_heap_walk()) {
2278 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_FIELD, referrer, referree, slot);
2279 } else {
2280 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_FIELD, referrer, referree, slot);
2281 }
2282 }
2283
2284 // report an array referencing an element object
2285 inline bool CallbackInvoker::report_constant_pool_reference(oop referrer, oop referree, jint index) {
2286 if (is_basic_heap_walk()) {
2287 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CONSTANT_POOL, referrer, referree, index);
2288 } else {
2289 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_CONSTANT_POOL, referrer, referree, index);
2290 }
2291 }
2292
2293 // A supporting closure used to process simple roots
2294 class SimpleRootsClosure : public OopClosure {
2295 private:
2296 jvmtiHeapReferenceKind _kind;
2297 bool _continue;
2298
2299 jvmtiHeapReferenceKind root_kind() { return _kind; }
2300
2301 public:
2302 void set_kind(jvmtiHeapReferenceKind kind) {
2303 _kind = kind;
2304 _continue = true;
2305 }
2306
2307 inline bool stopped() {
2308 return !_continue;
2309 }
2310
2311 void do_oop(oop* obj_p) {
2312 // iteration has terminated
2313 if (stopped()) {
2314 return;
2315 }
2316
2317 oop o = NativeAccess<AS_NO_KEEPALIVE>::oop_load(obj_p);
2318 // ignore null
2319 if (o == NULL) {
2320 return;
2321 }
2322
2323 assert(Universe::heap()->is_in(o), "should be impossible");
2324
2325 jvmtiHeapReferenceKind kind = root_kind();
2326
2327 // invoke the callback
2328 _continue = CallbackInvoker::report_simple_root(kind, o);
2329
2330 }
2331 virtual void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }
2332 };
2333
2334 // A supporting closure used to process JNI locals
2335 class JNILocalRootsClosure : public OopClosure {
2336 private:
2337 jlong _thread_tag;
2338 jlong _tid;
2339 jint _depth;
2340 jmethodID _method;
2341 bool _continue;
2342 public:
2343 void set_context(jlong thread_tag, jlong tid, jint depth, jmethodID method) {
2344 _thread_tag = thread_tag;
2345 _tid = tid;
2346 _depth = depth;
2347 _method = method;
2348 _continue = true;
2349 }
2350
2351 inline bool stopped() {
2352 return !_continue;
2353 }
2354
2355 void do_oop(oop* obj_p) {
2356 // iteration has terminated
2357 if (stopped()) {
2358 return;
2359 }
2360
2361 oop o = *obj_p;
2362 // ignore null
2363 if (o == NULL) {
2364 return;
2365 }
2366
2367 // invoke the callback
2368 _continue = CallbackInvoker::report_jni_local_root(_thread_tag, _tid, _depth, _method, o);
2369 }
2370 virtual void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }
2371 };
2372
2373
2374 // A VM operation to iterate over objects that are reachable from
2375 // a set of roots or an initial object.
2376 //
2377 // For VM_HeapWalkOperation the set of roots used is :-
2378 //
2379 // - All JNI global references
2380 // - All inflated monitors
2381 // - All classes loaded by the boot class loader (or all classes
2382 // in the event that class unloading is disabled)
2383 // - All java threads
2384 // - For each java thread then all locals and JNI local references
2385 // on the thread's execution stack
2386 // - All visible/explainable objects from Universes::oops_do
2387 //
2388 class VM_HeapWalkOperation: public VM_Operation {
2389 private:
2390 enum {
2391 initial_visit_stack_size = 4000
2392 };
2393
2394 bool _is_advanced_heap_walk; // indicates FollowReferences
2395 JvmtiTagMap* _tag_map;
2396 Handle _initial_object;
2397 GrowableArray<oop>* _visit_stack; // the visit stack
2398
2399 // Dead object tags in JvmtiTagMap
2400 GrowableArray<jlong>* _dead_objects;
2401
2402 bool _following_object_refs; // are we following object references
2403
2404 bool _reporting_primitive_fields; // optional reporting
2405 bool _reporting_primitive_array_values;
2406 bool _reporting_string_values;
2407
2408 GrowableArray<oop>* create_visit_stack() {
2409 return new (ResourceObj::C_HEAP, mtServiceability) GrowableArray<oop>(initial_visit_stack_size, mtServiceability);
2410 }
2411
2412 // accessors
2413 bool is_advanced_heap_walk() const { return _is_advanced_heap_walk; }
2414 JvmtiTagMap* tag_map() const { return _tag_map; }
2415 Handle initial_object() const { return _initial_object; }
2416
2417 bool is_following_references() const { return _following_object_refs; }
2418
2419 bool is_reporting_primitive_fields() const { return _reporting_primitive_fields; }
2420 bool is_reporting_primitive_array_values() const { return _reporting_primitive_array_values; }
2421 bool is_reporting_string_values() const { return _reporting_string_values; }
2422
2423 GrowableArray<oop>* visit_stack() const { return _visit_stack; }
2424
2425 // iterate over the various object types
2426 inline bool iterate_over_array(oop o);
2427 inline bool iterate_over_type_array(oop o);
2428 inline bool iterate_over_class(oop o);
2429 inline bool iterate_over_object(oop o);
2430
2431 // root collection
2432 inline bool collect_simple_roots();
2433 inline bool collect_stack_roots();
2434 inline bool collect_stack_roots(JavaThread* java_thread, JNILocalRootsClosure* blk);
2435
2436 // visit an object
2437 inline bool visit(oop o);
2438
2439 public:
2440 VM_HeapWalkOperation(JvmtiTagMap* tag_map,
2441 Handle initial_object,
2442 BasicHeapWalkContext callbacks,
2443 const void* user_data,
2444 GrowableArray<jlong>* objects);
2445
2446 VM_HeapWalkOperation(JvmtiTagMap* tag_map,
2447 Handle initial_object,
2448 AdvancedHeapWalkContext callbacks,
2449 const void* user_data,
2450 GrowableArray<jlong>* objects);
2451
2452 ~VM_HeapWalkOperation();
2453
2454 VMOp_Type type() const { return VMOp_HeapWalkOperation; }
2455 void doit();
2456 };
2457
2458
2459 VM_HeapWalkOperation::VM_HeapWalkOperation(JvmtiTagMap* tag_map,
2460 Handle initial_object,
2461 BasicHeapWalkContext callbacks,
2462 const void* user_data,
2463 GrowableArray<jlong>* objects) {
2464 _is_advanced_heap_walk = false;
2465 _tag_map = tag_map;
2466 _initial_object = initial_object;
2467 _following_object_refs = (callbacks.object_ref_callback() != NULL);
2468 _reporting_primitive_fields = false;
2469 _reporting_primitive_array_values = false;
2470 _reporting_string_values = false;
2471 _visit_stack = create_visit_stack();
2472 _dead_objects = objects;
2473
2474
2475 CallbackInvoker::initialize_for_basic_heap_walk(tag_map, _visit_stack, user_data, callbacks);
2476 }
2477
2478 VM_HeapWalkOperation::VM_HeapWalkOperation(JvmtiTagMap* tag_map,
2479 Handle initial_object,
2480 AdvancedHeapWalkContext callbacks,
2481 const void* user_data,
2482 GrowableArray<jlong>* objects) {
2483 _is_advanced_heap_walk = true;
2484 _tag_map = tag_map;
2485 _initial_object = initial_object;
2486 _following_object_refs = true;
2487 _reporting_primitive_fields = (callbacks.primitive_field_callback() != NULL);;
2488 _reporting_primitive_array_values = (callbacks.array_primitive_value_callback() != NULL);;
2489 _reporting_string_values = (callbacks.string_primitive_value_callback() != NULL);;
2490 _visit_stack = create_visit_stack();
2491 _dead_objects = objects;
2492
2493 CallbackInvoker::initialize_for_advanced_heap_walk(tag_map, _visit_stack, user_data, callbacks);
2494 }
2495
2496 VM_HeapWalkOperation::~VM_HeapWalkOperation() {
2497 if (_following_object_refs) {
2498 assert(_visit_stack != NULL, "checking");
2499 delete _visit_stack;
2500 _visit_stack = NULL;
2501 }
2502 }
2503
2504 // an array references its class and has a reference to
2505 // each element in the array
2506 inline bool VM_HeapWalkOperation::iterate_over_array(oop o) {
2507 objArrayOop array = objArrayOop(o);
2508
2509 // array reference to its class
2510 oop mirror = ObjArrayKlass::cast(array->klass())->java_mirror();
2511 if (!CallbackInvoker::report_class_reference(o, mirror)) {
2512 return false;
2513 }
2514
2515 // iterate over the array and report each reference to a
2516 // non-null element
2517 for (int index=0; index<array->length(); index++) {
2518 oop elem = array->obj_at(index);
2519 if (elem == NULL) {
2520 continue;
2521 }
2522
2523 // report the array reference o[index] = elem
2524 if (!CallbackInvoker::report_array_element_reference(o, elem, index)) {
2525 return false;
2526 }
2527 }
2528 return true;
2529 }
2530
2531 // a type array references its class
2532 inline bool VM_HeapWalkOperation::iterate_over_type_array(oop o) {
2533 Klass* k = o->klass();
2534 oop mirror = k->java_mirror();
2535 if (!CallbackInvoker::report_class_reference(o, mirror)) {
2536 return false;
2537 }
2538
2539 // report the array contents if required
2540 if (is_reporting_primitive_array_values()) {
2541 if (!CallbackInvoker::report_primitive_array_values(o)) {
2542 return false;
2543 }
2544 }
2545 return true;
2546 }
2547
2548 #ifdef ASSERT
2549 // verify that a static oop field is in range
2550 static inline bool verify_static_oop(InstanceKlass* ik,
2551 oop mirror, int offset) {
2552 address obj_p = cast_from_oop<address>(mirror) + offset;
2553 address start = (address)InstanceMirrorKlass::start_of_static_fields(mirror);
2554 address end = start + (java_lang_Class::static_oop_field_count(mirror) * heapOopSize);
2555 assert(end >= start, "sanity check");
2556
2557 if (obj_p >= start && obj_p < end) {
2558 return true;
2559 } else {
2560 return false;
2561 }
2562 }
2563 #endif // #ifdef ASSERT
2564
2565 // a class references its super class, interfaces, class loader, ...
2566 // and finally its static fields
2567 inline bool VM_HeapWalkOperation::iterate_over_class(oop java_class) {
2568 int i;
2569 Klass* klass = java_lang_Class::as_Klass(java_class);
2570
2571 if (klass->is_instance_klass()) {
2572 InstanceKlass* ik = InstanceKlass::cast(klass);
2573
2574 // Ignore the class if it hasn't been initialized yet
2575 if (!ik->is_linked()) {
2576 return true;
2577 }
2578
2579 // get the java mirror
2580 oop mirror = klass->java_mirror();
2581
2582 // super (only if something more interesting than java.lang.Object)
2583 InstanceKlass* java_super = ik->java_super();
2584 if (java_super != NULL && java_super != vmClasses::Object_klass()) {
2585 oop super = java_super->java_mirror();
2586 if (!CallbackInvoker::report_superclass_reference(mirror, super)) {
2587 return false;
2588 }
2589 }
2590
2591 // class loader
2592 oop cl = ik->class_loader();
2593 if (cl != NULL) {
2594 if (!CallbackInvoker::report_class_loader_reference(mirror, cl)) {
2595 return false;
2596 }
2597 }
2598
2599 // protection domain
2600 oop pd = ik->protection_domain();
2601 if (pd != NULL) {
2602 if (!CallbackInvoker::report_protection_domain_reference(mirror, pd)) {
2603 return false;
2604 }
2605 }
2606
2607 // signers
2608 oop signers = ik->signers();
2609 if (signers != NULL) {
2610 if (!CallbackInvoker::report_signers_reference(mirror, signers)) {
2611 return false;
2612 }
2613 }
2614
2615 // references from the constant pool
2616 {
2617 ConstantPool* pool = ik->constants();
2618 for (int i = 1; i < pool->length(); i++) {
2619 constantTag tag = pool->tag_at(i).value();
2620 if (tag.is_string() || tag.is_klass() || tag.is_unresolved_klass()) {
2621 oop entry;
2622 if (tag.is_string()) {
2623 entry = pool->resolved_string_at(i);
2624 // If the entry is non-null it is resolved.
2625 if (entry == NULL) {
2626 continue;
2627 }
2628 } else if (tag.is_klass()) {
2629 entry = pool->resolved_klass_at(i)->java_mirror();
2630 } else {
2631 // Code generated by JIT compilers might not resolve constant
2632 // pool entries. Treat them as resolved if they are loaded.
2633 assert(tag.is_unresolved_klass(), "must be");
2634 constantPoolHandle cp(Thread::current(), pool);
2635 Klass* klass = ConstantPool::klass_at_if_loaded(cp, i);
2636 if (klass == NULL) {
2637 continue;
2638 }
2639 entry = klass->java_mirror();
2640 }
2641 if (!CallbackInvoker::report_constant_pool_reference(mirror, entry, (jint)i)) {
2642 return false;
2643 }
2644 }
2645 }
2646 }
2647
2648 // interfaces
2649 // (These will already have been reported as references from the constant pool
2650 // but are specified by IterateOverReachableObjects and must be reported).
2651 Array<InstanceKlass*>* interfaces = ik->local_interfaces();
2652 for (i = 0; i < interfaces->length(); i++) {
2653 oop interf = interfaces->at(i)->java_mirror();
2654 if (interf == NULL) {
2655 continue;
2656 }
2657 if (!CallbackInvoker::report_interface_reference(mirror, interf)) {
2658 return false;
2659 }
2660 }
2661
2662 // iterate over the static fields
2663
2664 ClassFieldMap* field_map = ClassFieldMap::create_map_of_static_fields(klass);
2665 for (i=0; i<field_map->field_count(); i++) {
2666 ClassFieldDescriptor* field = field_map->field_at(i);
2667 char type = field->field_type();
2668 if (!is_primitive_field_type(type)) {
2669 oop fld_o = mirror->obj_field(field->field_offset());
2670 assert(verify_static_oop(ik, mirror, field->field_offset()), "sanity check");
2671 if (fld_o != NULL) {
2672 int slot = field->field_index();
2673 if (!CallbackInvoker::report_static_field_reference(mirror, fld_o, slot)) {
2674 delete field_map;
2675 return false;
2676 }
2677 }
2678 } else {
2679 if (is_reporting_primitive_fields()) {
2680 address addr = cast_from_oop<address>(mirror) + field->field_offset();
2681 int slot = field->field_index();
2682 if (!CallbackInvoker::report_primitive_static_field(mirror, slot, addr, type)) {
2683 delete field_map;
2684 return false;
2685 }
2686 }
2687 }
2688 }
2689 delete field_map;
2690
2691 return true;
2692 }
2693
2694 return true;
2695 }
2696
2697 // an object references a class and its instance fields
2698 // (static fields are ignored here as we report these as
2699 // references from the class).
2700 inline bool VM_HeapWalkOperation::iterate_over_object(oop o) {
2701 // reference to the class
2702 if (!CallbackInvoker::report_class_reference(o, o->klass()->java_mirror())) {
2703 return false;
2704 }
2705
2706 // iterate over instance fields
2707 ClassFieldMap* field_map = JvmtiCachedClassFieldMap::get_map_of_instance_fields(o);
2708 for (int i=0; i<field_map->field_count(); i++) {
2709 ClassFieldDescriptor* field = field_map->field_at(i);
2710 char type = field->field_type();
2711 if (!is_primitive_field_type(type)) {
2712 oop fld_o = o->obj_field_access<AS_NO_KEEPALIVE | ON_UNKNOWN_OOP_REF>(field->field_offset());
2713 // ignore any objects that aren't visible to profiler
2714 if (fld_o != NULL) {
2715 assert(Universe::heap()->is_in(fld_o), "unsafe code should not "
2716 "have references to Klass* anymore");
2717 int slot = field->field_index();
2718 if (!CallbackInvoker::report_field_reference(o, fld_o, slot)) {
2719 return false;
2720 }
2721 }
2722 } else {
2723 if (is_reporting_primitive_fields()) {
2724 // primitive instance field
2725 address addr = cast_from_oop<address>(o) + field->field_offset();
2726 int slot = field->field_index();
2727 if (!CallbackInvoker::report_primitive_instance_field(o, slot, addr, type)) {
2728 return false;
2729 }
2730 }
2731 }
2732 }
2733
2734 // if the object is a java.lang.String
2735 if (is_reporting_string_values() &&
2736 o->klass() == vmClasses::String_klass()) {
2737 if (!CallbackInvoker::report_string_value(o)) {
2738 return false;
2739 }
2740 }
2741 return true;
2742 }
2743
2744
2745 // Collects all simple (non-stack) roots except for threads;
2746 // threads are handled in collect_stack_roots() as an optimization.
2747 // if there's a heap root callback provided then the callback is
2748 // invoked for each simple root.
2749 // if an object reference callback is provided then all simple
2750 // roots are pushed onto the marking stack so that they can be
2751 // processed later
2752 //
2753 inline bool VM_HeapWalkOperation::collect_simple_roots() {
2754 SimpleRootsClosure blk;
2755
2756 // JNI globals
2757 blk.set_kind(JVMTI_HEAP_REFERENCE_JNI_GLOBAL);
2758 JNIHandles::oops_do(&blk);
2759 if (blk.stopped()) {
2760 return false;
2761 }
2762
2763 // Preloaded classes and loader from the system dictionary
2764 blk.set_kind(JVMTI_HEAP_REFERENCE_SYSTEM_CLASS);
2765 CLDToOopClosure cld_closure(&blk, false);
2766 ClassLoaderDataGraph::always_strong_cld_do(&cld_closure);
2767 if (blk.stopped()) {
2768 return false;
2769 }
2770
2771 // threads are now handled in collect_stack_roots()
2772
2773 // Other kinds of roots maintained by HotSpot
2774 // Many of these won't be visible but others (such as instances of important
2775 // exceptions) will be visible.
2776 blk.set_kind(JVMTI_HEAP_REFERENCE_OTHER);
2777 Universe::vm_global()->oops_do(&blk);
2778 if (blk.stopped()) {
2779 return false;
2780 }
2781
2782 return true;
2783 }
2784
2785 // Walk the stack of a given thread and find all references (locals
2786 // and JNI calls) and report these as stack references
2787 inline bool VM_HeapWalkOperation::collect_stack_roots(JavaThread* java_thread,
2788 JNILocalRootsClosure* blk)
2789 {
2790 oop threadObj = java_thread->threadObj();
2791 assert(threadObj != NULL, "sanity check");
2792
2793 // only need to get the thread's tag once per thread
2794 jlong thread_tag = tag_for(_tag_map, threadObj);
2795
2796 // also need the thread id
2797 jlong tid = java_lang_Thread::thread_id(threadObj);
2798
2799
2800 if (java_thread->has_last_Java_frame()) {
2801
2802 // vframes are resource allocated
2803 Thread* current_thread = Thread::current();
2804 ResourceMark rm(current_thread);
2805 HandleMark hm(current_thread);
2806
2807 RegisterMap reg_map(java_thread);
2808 frame f = java_thread->last_frame();
2809 vframe* vf = vframe::new_vframe(&f, ®_map, java_thread);
2810
2811 bool is_top_frame = true;
2812 int depth = 0;
2813 frame* last_entry_frame = NULL;
2814
2815 while (vf != NULL) {
2816 if (vf->is_java_frame()) {
2817
2818 // java frame (interpreted, compiled, ...)
2819 javaVFrame *jvf = javaVFrame::cast(vf);
2820
2821 // the jmethodID
2822 jmethodID method = jvf->method()->jmethod_id();
2823
2824 if (!(jvf->method()->is_native())) {
2825 jlocation bci = (jlocation)jvf->bci();
2826 StackValueCollection* locals = jvf->locals();
2827 for (int slot=0; slot<locals->size(); slot++) {
2828 if (locals->at(slot)->type() == T_OBJECT) {
2829 oop o = locals->obj_at(slot)();
2830 if (o == NULL) {
2831 continue;
2832 }
2833
2834 // stack reference
2835 if (!CallbackInvoker::report_stack_ref_root(thread_tag, tid, depth, method,
2836 bci, slot, o)) {
2837 return false;
2838 }
2839 }
2840 }
2841
2842 StackValueCollection* exprs = jvf->expressions();
2843 for (int index=0; index < exprs->size(); index++) {
2844 if (exprs->at(index)->type() == T_OBJECT) {
2845 oop o = exprs->obj_at(index)();
2846 if (o == NULL) {
2847 continue;
2848 }
2849
2850 // stack reference
2851 if (!CallbackInvoker::report_stack_ref_root(thread_tag, tid, depth, method,
2852 bci, locals->size() + index, o)) {
2853 return false;
2854 }
2855 }
2856 }
2857
2858 // Follow oops from compiled nmethod
2859 if (jvf->cb() != NULL && jvf->cb()->is_nmethod()) {
2860 blk->set_context(thread_tag, tid, depth, method);
2861 jvf->cb()->as_nmethod()->oops_do(blk);
2862 }
2863 } else {
2864 blk->set_context(thread_tag, tid, depth, method);
2865 if (is_top_frame) {
2866 // JNI locals for the top frame.
2867 java_thread->active_handles()->oops_do(blk);
2868 } else {
2869 if (last_entry_frame != NULL) {
2870 // JNI locals for the entry frame
2871 assert(last_entry_frame->is_entry_frame(), "checking");
2872 last_entry_frame->entry_frame_call_wrapper()->handles()->oops_do(blk);
2873 }
2874 }
2875 }
2876 last_entry_frame = NULL;
2877 depth++;
2878 } else {
2879 // externalVFrame - for an entry frame then we report the JNI locals
2880 // when we find the corresponding javaVFrame
2881 frame* fr = vf->frame_pointer();
2882 assert(fr != NULL, "sanity check");
2883 if (fr->is_entry_frame()) {
2884 last_entry_frame = fr;
2885 }
2886 }
2887
2888 vf = vf->sender();
2889 is_top_frame = false;
2890 }
2891 } else {
2892 // no last java frame but there may be JNI locals
2893 blk->set_context(thread_tag, tid, 0, (jmethodID)NULL);
2894 java_thread->active_handles()->oops_do(blk);
2895 }
2896 return true;
2897 }
2898
2899
2900 // Collects the simple roots for all threads and collects all
2901 // stack roots - for each thread it walks the execution
2902 // stack to find all references and local JNI refs.
2903 inline bool VM_HeapWalkOperation::collect_stack_roots() {
2904 JNILocalRootsClosure blk;
2905 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thread = jtiwh.next(); ) {
2906 oop threadObj = thread->threadObj();
2907 if (threadObj != NULL && !thread->is_exiting() && !thread->is_hidden_from_external_view()) {
2908 // Collect the simple root for this thread before we
2909 // collect its stack roots
2910 if (!CallbackInvoker::report_simple_root(JVMTI_HEAP_REFERENCE_THREAD,
2911 threadObj)) {
2912 return false;
2913 }
2914 if (!collect_stack_roots(thread, &blk)) {
2915 return false;
2916 }
2917 }
2918 }
2919 return true;
2920 }
2921
2922 // visit an object
2923 // first mark the object as visited
2924 // second get all the outbound references from this object (in other words, all
2925 // the objects referenced by this object).
2926 //
2927 bool VM_HeapWalkOperation::visit(oop o) {
2928 // mark object as visited
2929 assert(!ObjectMarker::visited(o), "can't visit same object more than once");
2930 ObjectMarker::mark(o);
2931
2932 // instance
2933 if (o->is_instance()) {
2934 if (o->klass() == vmClasses::Class_klass()) {
2935 if (!java_lang_Class::is_primitive(o)) {
2936 // a java.lang.Class
2937 return iterate_over_class(o);
2938 }
2939 } else {
2940 return iterate_over_object(o);
2941 }
2942 }
2943
2944 // object array
2945 if (o->is_objArray()) {
2946 return iterate_over_array(o);
2947 }
2948
2949 // type array
2950 if (o->is_typeArray()) {
2951 return iterate_over_type_array(o);
2952 }
2953
2954 return true;
2955 }
2956
2957 void VM_HeapWalkOperation::doit() {
2958 ResourceMark rm;
2959 ObjectMarkerController marker;
2960 ClassFieldMapCacheMark cm;
2961
2962 JvmtiTagMap::check_hashmaps_for_heapwalk(_dead_objects);
2963
2964 assert(visit_stack()->is_empty(), "visit stack must be empty");
2965
2966 // the heap walk starts with an initial object or the heap roots
2967 if (initial_object().is_null()) {
2968 // If either collect_stack_roots() or collect_simple_roots()
2969 // returns false at this point, then there are no mark bits
2970 // to reset.
2971 ObjectMarker::set_needs_reset(false);
2972
2973 // Calling collect_stack_roots() before collect_simple_roots()
2974 // can result in a big performance boost for an agent that is
2975 // focused on analyzing references in the thread stacks.
2976 if (!collect_stack_roots()) return;
2977
2978 if (!collect_simple_roots()) return;
2979
2980 // no early return so enable heap traversal to reset the mark bits
2981 ObjectMarker::set_needs_reset(true);
2982 } else {
2983 visit_stack()->push(initial_object()());
2984 }
2985
2986 // object references required
2987 if (is_following_references()) {
2988
2989 // visit each object until all reachable objects have been
2990 // visited or the callback asked to terminate the iteration.
2991 while (!visit_stack()->is_empty()) {
2992 oop o = visit_stack()->pop();
2993 if (!ObjectMarker::visited(o)) {
2994 if (!visit(o)) {
2995 break;
2996 }
2997 }
2998 }
2999 }
3000 }
3001
3002 // iterate over all objects that are reachable from a set of roots
3003 void JvmtiTagMap::iterate_over_reachable_objects(jvmtiHeapRootCallback heap_root_callback,
3004 jvmtiStackReferenceCallback stack_ref_callback,
3005 jvmtiObjectReferenceCallback object_ref_callback,
3006 const void* user_data) {
3007 JavaThread* jt = JavaThread::current();
3008 EscapeBarrier eb(true, jt);
3009 eb.deoptimize_objects_all_threads();
3010 Arena dead_object_arena(mtServiceability);
3011 GrowableArray<jlong> dead_objects(&dead_object_arena, 10, 0, 0);
3012 {
3013 MutexLocker ml(Heap_lock);
3014 BasicHeapWalkContext context(heap_root_callback, stack_ref_callback, object_ref_callback);
3015 VM_HeapWalkOperation op(this, Handle(), context, user_data, &dead_objects);
3016 VMThread::execute(&op);
3017 }
3018 // Post events outside of Heap_lock
3019 post_dead_objects(&dead_objects);
3020 }
3021
3022 // iterate over all objects that are reachable from a given object
3023 void JvmtiTagMap::iterate_over_objects_reachable_from_object(jobject object,
3024 jvmtiObjectReferenceCallback object_ref_callback,
3025 const void* user_data) {
3026 oop obj = JNIHandles::resolve(object);
3027 Handle initial_object(Thread::current(), obj);
3028
3029 Arena dead_object_arena(mtServiceability);
3030 GrowableArray<jlong> dead_objects(&dead_object_arena, 10, 0, 0);
3031 {
3032 MutexLocker ml(Heap_lock);
3033 BasicHeapWalkContext context(NULL, NULL, object_ref_callback);
3034 VM_HeapWalkOperation op(this, initial_object, context, user_data, &dead_objects);
3035 VMThread::execute(&op);
3036 }
3037 // Post events outside of Heap_lock
3038 post_dead_objects(&dead_objects);
3039 }
3040
3041 // follow references from an initial object or the GC roots
3042 void JvmtiTagMap::follow_references(jint heap_filter,
3043 Klass* klass,
3044 jobject object,
3045 const jvmtiHeapCallbacks* callbacks,
3046 const void* user_data)
3047 {
3048 oop obj = JNIHandles::resolve(object);
3049 JavaThread* jt = JavaThread::current();
3050 Handle initial_object(jt, obj);
3051 // EA based optimizations that are tagged or reachable from initial_object are already reverted.
3052 EscapeBarrier eb(initial_object.is_null() &&
3053 !(heap_filter & JVMTI_HEAP_FILTER_UNTAGGED),
3054 jt);
3055 eb.deoptimize_objects_all_threads();
3056
3057 Arena dead_object_arena(mtServiceability);
3058 GrowableArray<jlong> dead_objects(&dead_object_arena, 10, 0, 0);
3059 {
3060 MutexLocker ml(Heap_lock);
3061 AdvancedHeapWalkContext context(heap_filter, klass, callbacks);
3062 VM_HeapWalkOperation op(this, initial_object, context, user_data, &dead_objects);
3063 VMThread::execute(&op);
3064 }
3065 // Post events outside of Heap_lock
3066 post_dead_objects(&dead_objects);
3067 }
3068
3069 // Concurrent GC needs to call this in relocation pause, so after the objects are moved
3070 // and have their new addresses, the table can be rehashed.
3071 void JvmtiTagMap::set_needs_rehashing() {
3072 assert(SafepointSynchronize::is_at_safepoint(), "called in gc pause");
3073 assert(Thread::current()->is_VM_thread(), "should be the VM thread");
3074
3075 JvmtiEnvIterator it;
3076 for (JvmtiEnv* env = it.first(); env != NULL; env = it.next(env)) {
3077 JvmtiTagMap* tag_map = env->tag_map_acquire();
3078 if (tag_map != NULL) {
3079 tag_map->_needs_rehashing = true;
3080 }
3081 }
3082 }
3083
3084 // Verify gc_notification follows set_needs_cleaning.
3085 DEBUG_ONLY(static bool notified_needs_cleaning = false;)
3086
3087 void JvmtiTagMap::set_needs_cleaning() {
3088 assert(SafepointSynchronize::is_at_safepoint(), "called in gc pause");
3089 assert(Thread::current()->is_VM_thread(), "should be the VM thread");
3090 // Can't assert !notified_needs_cleaning; a partial GC might be upgraded
3091 // to a full GC and do this twice without intervening gc_notification.
3092 DEBUG_ONLY(notified_needs_cleaning = true;)
3093
3094 JvmtiEnvIterator it;
3095 for (JvmtiEnv* env = it.first(); env != NULL; env = it.next(env)) {
3096 JvmtiTagMap* tag_map = env->tag_map_acquire();
3097 if (tag_map != NULL) {
3098 tag_map->_needs_cleaning = !tag_map->is_empty();
3099 }
3100 }
3101 }
3102
3103 void JvmtiTagMap::gc_notification(size_t num_dead_entries) {
3104 assert(notified_needs_cleaning, "missing GC notification");
3105 DEBUG_ONLY(notified_needs_cleaning = false;)
3106
3107 // Notify ServiceThread if there's work to do.
3108 {
3109 MonitorLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
3110 _has_object_free_events = (num_dead_entries != 0);
3111 if (_has_object_free_events) ml.notify_all();
3112 }
3113
3114 // If no dead entries then cancel cleaning requests.
3115 if (num_dead_entries == 0) {
3116 JvmtiEnvIterator it;
3117 for (JvmtiEnv* env = it.first(); env != NULL; env = it.next(env)) {
3118 JvmtiTagMap* tag_map = env->tag_map_acquire();
3119 if (tag_map != NULL) {
3120 MutexLocker ml (tag_map->lock(), Mutex::_no_safepoint_check_flag);
3121 tag_map->_needs_cleaning = false;
3122 }
3123 }
3124 }
3125 }
3126
3127 // Used by ServiceThread to discover there is work to do.
3128 bool JvmtiTagMap::has_object_free_events_and_reset() {
3129 assert_lock_strong(Service_lock);
3130 bool result = _has_object_free_events;
3131 _has_object_free_events = false;
3132 return result;
3133 }
3134
3135 // Used by ServiceThread to clean up tagmaps.
3136 void JvmtiTagMap::flush_all_object_free_events() {
3137 JavaThread* thread = JavaThread::current();
3138 JvmtiEnvIterator it;
3139 for (JvmtiEnv* env = it.first(); env != NULL; env = it.next(env)) {
3140 JvmtiTagMap* tag_map = env->tag_map_acquire();
3141 if (tag_map != NULL) {
3142 tag_map->flush_object_free_events();
3143 ThreadBlockInVM tbiv(thread); // Be safepoint-polite while looping.
3144 }
3145 }
3146 }