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 if (mark.has_displaced_mark_helper()) {
1471 mark = mark.displaced_mark_helper();
1472 }
1473 o->set_mark(mark.set_marked());
1474 }
1475
1476 // return true if object is marked
1477 inline bool ObjectMarker::visited(oop o) {
1478 return o->mark().is_marked();
1479 }
1480
1481 // Stack allocated class to help ensure that ObjectMarker is used
1482 // correctly. Constructor initializes ObjectMarker, destructor calls
1483 // ObjectMarker's done() function to restore object headers.
1484 class ObjectMarkerController : public StackObj {
1485 public:
1486 ObjectMarkerController() {
1487 ObjectMarker::init();
1488 }
1489 ~ObjectMarkerController() {
1490 ObjectMarker::done();
1491 }
1492 };
1493
1494
1495 // helper to map a jvmtiHeapReferenceKind to an old style jvmtiHeapRootKind
1496 // (not performance critical as only used for roots)
1497 static jvmtiHeapRootKind toJvmtiHeapRootKind(jvmtiHeapReferenceKind kind) {
1498 switch (kind) {
1499 case JVMTI_HEAP_REFERENCE_JNI_GLOBAL: return JVMTI_HEAP_ROOT_JNI_GLOBAL;
1500 case JVMTI_HEAP_REFERENCE_SYSTEM_CLASS: return JVMTI_HEAP_ROOT_SYSTEM_CLASS;
1501 case JVMTI_HEAP_REFERENCE_STACK_LOCAL: return JVMTI_HEAP_ROOT_STACK_LOCAL;
1502 case JVMTI_HEAP_REFERENCE_JNI_LOCAL: return JVMTI_HEAP_ROOT_JNI_LOCAL;
1503 case JVMTI_HEAP_REFERENCE_THREAD: return JVMTI_HEAP_ROOT_THREAD;
1504 case JVMTI_HEAP_REFERENCE_OTHER: return JVMTI_HEAP_ROOT_OTHER;
1505 default: ShouldNotReachHere(); return JVMTI_HEAP_ROOT_OTHER;
1506 }
1507 }
1508
1509 // Base class for all heap walk contexts. The base class maintains a flag
1510 // to indicate if the context is valid or not.
1511 class HeapWalkContext {
1512 private:
1513 bool _valid;
1514 public:
1515 HeapWalkContext(bool valid) { _valid = valid; }
1516 void invalidate() { _valid = false; }
1517 bool is_valid() const { return _valid; }
1518 };
1519
1520 // A basic heap walk context for the deprecated heap walking functions.
1521 // The context for a basic heap walk are the callbacks and fields used by
1522 // the referrer caching scheme.
1523 class BasicHeapWalkContext: public HeapWalkContext {
1524 private:
1525 jvmtiHeapRootCallback _heap_root_callback;
1526 jvmtiStackReferenceCallback _stack_ref_callback;
1527 jvmtiObjectReferenceCallback _object_ref_callback;
1528
1529 // used for caching
1530 oop _last_referrer;
1531 jlong _last_referrer_tag;
1532
1533 public:
1534 BasicHeapWalkContext() : HeapWalkContext(false) { }
1535
1536 BasicHeapWalkContext(jvmtiHeapRootCallback heap_root_callback,
1537 jvmtiStackReferenceCallback stack_ref_callback,
1538 jvmtiObjectReferenceCallback object_ref_callback) :
1539 HeapWalkContext(true),
1540 _heap_root_callback(heap_root_callback),
1541 _stack_ref_callback(stack_ref_callback),
1542 _object_ref_callback(object_ref_callback),
1543 _last_referrer(NULL),
1544 _last_referrer_tag(0) {
1545 }
1546
1547 // accessors
1548 jvmtiHeapRootCallback heap_root_callback() const { return _heap_root_callback; }
1549 jvmtiStackReferenceCallback stack_ref_callback() const { return _stack_ref_callback; }
1550 jvmtiObjectReferenceCallback object_ref_callback() const { return _object_ref_callback; }
1551
1552 oop last_referrer() const { return _last_referrer; }
1553 void set_last_referrer(oop referrer) { _last_referrer = referrer; }
1554 jlong last_referrer_tag() const { return _last_referrer_tag; }
1555 void set_last_referrer_tag(jlong value) { _last_referrer_tag = value; }
1556 };
1557
1558 // The advanced heap walk context for the FollowReferences functions.
1559 // The context is the callbacks, and the fields used for filtering.
1560 class AdvancedHeapWalkContext: public HeapWalkContext {
1561 private:
1562 jint _heap_filter;
1563 Klass* _klass_filter;
1564 const jvmtiHeapCallbacks* _heap_callbacks;
1565
1566 public:
1567 AdvancedHeapWalkContext() : HeapWalkContext(false) { }
1568
1569 AdvancedHeapWalkContext(jint heap_filter,
1570 Klass* klass_filter,
1571 const jvmtiHeapCallbacks* heap_callbacks) :
1572 HeapWalkContext(true),
1573 _heap_filter(heap_filter),
1574 _klass_filter(klass_filter),
1575 _heap_callbacks(heap_callbacks) {
1576 }
1577
1578 // accessors
1579 jint heap_filter() const { return _heap_filter; }
1580 Klass* klass_filter() const { return _klass_filter; }
1581
1582 const jvmtiHeapReferenceCallback heap_reference_callback() const {
1583 return _heap_callbacks->heap_reference_callback;
1584 };
1585 const jvmtiPrimitiveFieldCallback primitive_field_callback() const {
1586 return _heap_callbacks->primitive_field_callback;
1587 }
1588 const jvmtiArrayPrimitiveValueCallback array_primitive_value_callback() const {
1589 return _heap_callbacks->array_primitive_value_callback;
1590 }
1591 const jvmtiStringPrimitiveValueCallback string_primitive_value_callback() const {
1592 return _heap_callbacks->string_primitive_value_callback;
1593 }
1594 };
1595
1596 // The CallbackInvoker is a class with static functions that the heap walk can call
1597 // into to invoke callbacks. It works in one of two modes. The "basic" mode is
1598 // used for the deprecated IterateOverReachableObjects functions. The "advanced"
1599 // mode is for the newer FollowReferences function which supports a lot of
1600 // additional callbacks.
1601 class CallbackInvoker : AllStatic {
1602 private:
1603 // heap walk styles
1604 enum { basic, advanced };
1605 static int _heap_walk_type;
1606 static bool is_basic_heap_walk() { return _heap_walk_type == basic; }
1607 static bool is_advanced_heap_walk() { return _heap_walk_type == advanced; }
1608
1609 // context for basic style heap walk
1610 static BasicHeapWalkContext _basic_context;
1611 static BasicHeapWalkContext* basic_context() {
1612 assert(_basic_context.is_valid(), "invalid");
1613 return &_basic_context;
1614 }
1615
1616 // context for advanced style heap walk
1617 static AdvancedHeapWalkContext _advanced_context;
1618 static AdvancedHeapWalkContext* advanced_context() {
1619 assert(_advanced_context.is_valid(), "invalid");
1620 return &_advanced_context;
1621 }
1622
1623 // context needed for all heap walks
1624 static JvmtiTagMap* _tag_map;
1625 static const void* _user_data;
1626 static GrowableArray<oop>* _visit_stack;
1627
1628 // accessors
1629 static JvmtiTagMap* tag_map() { return _tag_map; }
1630 static const void* user_data() { return _user_data; }
1631 static GrowableArray<oop>* visit_stack() { return _visit_stack; }
1632
1633 // if the object hasn't been visited then push it onto the visit stack
1634 // so that it will be visited later
1635 static inline bool check_for_visit(oop obj) {
1636 if (!ObjectMarker::visited(obj)) visit_stack()->push(obj);
1637 return true;
1638 }
1639
1640 // invoke basic style callbacks
1641 static inline bool invoke_basic_heap_root_callback
1642 (jvmtiHeapRootKind root_kind, oop obj);
1643 static inline bool invoke_basic_stack_ref_callback
1644 (jvmtiHeapRootKind root_kind, jlong thread_tag, jint depth, jmethodID method,
1645 int slot, oop obj);
1646 static inline bool invoke_basic_object_reference_callback
1647 (jvmtiObjectReferenceKind ref_kind, oop referrer, oop referree, jint index);
1648
1649 // invoke advanced style callbacks
1650 static inline bool invoke_advanced_heap_root_callback
1651 (jvmtiHeapReferenceKind ref_kind, oop obj);
1652 static inline bool invoke_advanced_stack_ref_callback
1653 (jvmtiHeapReferenceKind ref_kind, jlong thread_tag, jlong tid, int depth,
1654 jmethodID method, jlocation bci, jint slot, oop obj);
1655 static inline bool invoke_advanced_object_reference_callback
1656 (jvmtiHeapReferenceKind ref_kind, oop referrer, oop referree, jint index);
1657
1658 // used to report the value of primitive fields
1659 static inline bool report_primitive_field
1660 (jvmtiHeapReferenceKind ref_kind, oop obj, jint index, address addr, char type);
1661
1662 public:
1663 // initialize for basic mode
1664 static void initialize_for_basic_heap_walk(JvmtiTagMap* tag_map,
1665 GrowableArray<oop>* visit_stack,
1666 const void* user_data,
1667 BasicHeapWalkContext context);
1668
1669 // initialize for advanced mode
1670 static void initialize_for_advanced_heap_walk(JvmtiTagMap* tag_map,
1671 GrowableArray<oop>* visit_stack,
1672 const void* user_data,
1673 AdvancedHeapWalkContext context);
1674
1675 // functions to report roots
1676 static inline bool report_simple_root(jvmtiHeapReferenceKind kind, oop o);
1677 static inline bool report_jni_local_root(jlong thread_tag, jlong tid, jint depth,
1678 jmethodID m, oop o);
1679 static inline bool report_stack_ref_root(jlong thread_tag, jlong tid, jint depth,
1680 jmethodID method, jlocation bci, jint slot, oop o);
1681
1682 // functions to report references
1683 static inline bool report_array_element_reference(oop referrer, oop referree, jint index);
1684 static inline bool report_class_reference(oop referrer, oop referree);
1685 static inline bool report_class_loader_reference(oop referrer, oop referree);
1686 static inline bool report_signers_reference(oop referrer, oop referree);
1687 static inline bool report_protection_domain_reference(oop referrer, oop referree);
1688 static inline bool report_superclass_reference(oop referrer, oop referree);
1689 static inline bool report_interface_reference(oop referrer, oop referree);
1690 static inline bool report_static_field_reference(oop referrer, oop referree, jint slot);
1691 static inline bool report_field_reference(oop referrer, oop referree, jint slot);
1692 static inline bool report_constant_pool_reference(oop referrer, oop referree, jint index);
1693 static inline bool report_primitive_array_values(oop array);
1694 static inline bool report_string_value(oop str);
1695 static inline bool report_primitive_instance_field(oop o, jint index, address value, char type);
1696 static inline bool report_primitive_static_field(oop o, jint index, address value, char type);
1697 };
1698
1699 // statics
1700 int CallbackInvoker::_heap_walk_type;
1701 BasicHeapWalkContext CallbackInvoker::_basic_context;
1702 AdvancedHeapWalkContext CallbackInvoker::_advanced_context;
1703 JvmtiTagMap* CallbackInvoker::_tag_map;
1704 const void* CallbackInvoker::_user_data;
1705 GrowableArray<oop>* CallbackInvoker::_visit_stack;
1706
1707 // initialize for basic heap walk (IterateOverReachableObjects et al)
1708 void CallbackInvoker::initialize_for_basic_heap_walk(JvmtiTagMap* tag_map,
1709 GrowableArray<oop>* visit_stack,
1710 const void* user_data,
1711 BasicHeapWalkContext context) {
1712 _tag_map = tag_map;
1713 _visit_stack = visit_stack;
1714 _user_data = user_data;
1715 _basic_context = context;
1716 _advanced_context.invalidate(); // will trigger assertion if used
1717 _heap_walk_type = basic;
1718 }
1719
1720 // initialize for advanced heap walk (FollowReferences)
1721 void CallbackInvoker::initialize_for_advanced_heap_walk(JvmtiTagMap* tag_map,
1722 GrowableArray<oop>* visit_stack,
1723 const void* user_data,
1724 AdvancedHeapWalkContext context) {
1725 _tag_map = tag_map;
1726 _visit_stack = visit_stack;
1727 _user_data = user_data;
1728 _advanced_context = context;
1729 _basic_context.invalidate(); // will trigger assertion if used
1730 _heap_walk_type = advanced;
1731 }
1732
1733
1734 // invoke basic style heap root callback
1735 inline bool CallbackInvoker::invoke_basic_heap_root_callback(jvmtiHeapRootKind root_kind, oop obj) {
1736 // if we heap roots should be reported
1737 jvmtiHeapRootCallback cb = basic_context()->heap_root_callback();
1738 if (cb == NULL) {
1739 return check_for_visit(obj);
1740 }
1741
1742 CallbackWrapper wrapper(tag_map(), obj);
1743 jvmtiIterationControl control = (*cb)(root_kind,
1744 wrapper.klass_tag(),
1745 wrapper.obj_size(),
1746 wrapper.obj_tag_p(),
1747 (void*)user_data());
1748 // push root to visit stack when following references
1749 if (control == JVMTI_ITERATION_CONTINUE &&
1750 basic_context()->object_ref_callback() != NULL) {
1751 visit_stack()->push(obj);
1752 }
1753 return control != JVMTI_ITERATION_ABORT;
1754 }
1755
1756 // invoke basic style stack ref callback
1757 inline bool CallbackInvoker::invoke_basic_stack_ref_callback(jvmtiHeapRootKind root_kind,
1758 jlong thread_tag,
1759 jint depth,
1760 jmethodID method,
1761 int slot,
1762 oop obj) {
1763 // if we stack refs should be reported
1764 jvmtiStackReferenceCallback cb = basic_context()->stack_ref_callback();
1765 if (cb == NULL) {
1766 return check_for_visit(obj);
1767 }
1768
1769 CallbackWrapper wrapper(tag_map(), obj);
1770 jvmtiIterationControl control = (*cb)(root_kind,
1771 wrapper.klass_tag(),
1772 wrapper.obj_size(),
1773 wrapper.obj_tag_p(),
1774 thread_tag,
1775 depth,
1776 method,
1777 slot,
1778 (void*)user_data());
1779 // push root to visit stack when following references
1780 if (control == JVMTI_ITERATION_CONTINUE &&
1781 basic_context()->object_ref_callback() != NULL) {
1782 visit_stack()->push(obj);
1783 }
1784 return control != JVMTI_ITERATION_ABORT;
1785 }
1786
1787 // invoke basic style object reference callback
1788 inline bool CallbackInvoker::invoke_basic_object_reference_callback(jvmtiObjectReferenceKind ref_kind,
1789 oop referrer,
1790 oop referree,
1791 jint index) {
1792
1793 BasicHeapWalkContext* context = basic_context();
1794
1795 // callback requires the referrer's tag. If it's the same referrer
1796 // as the last call then we use the cached value.
1797 jlong referrer_tag;
1798 if (referrer == context->last_referrer()) {
1799 referrer_tag = context->last_referrer_tag();
1800 } else {
1801 referrer_tag = tag_for(tag_map(), referrer);
1802 }
1803
1804 // do the callback
1805 CallbackWrapper wrapper(tag_map(), referree);
1806 jvmtiObjectReferenceCallback cb = context->object_ref_callback();
1807 jvmtiIterationControl control = (*cb)(ref_kind,
1808 wrapper.klass_tag(),
1809 wrapper.obj_size(),
1810 wrapper.obj_tag_p(),
1811 referrer_tag,
1812 index,
1813 (void*)user_data());
1814
1815 // record referrer and referrer tag. For self-references record the
1816 // tag value from the callback as this might differ from referrer_tag.
1817 context->set_last_referrer(referrer);
1818 if (referrer == referree) {
1819 context->set_last_referrer_tag(*wrapper.obj_tag_p());
1820 } else {
1821 context->set_last_referrer_tag(referrer_tag);
1822 }
1823
1824 if (control == JVMTI_ITERATION_CONTINUE) {
1825 return check_for_visit(referree);
1826 } else {
1827 return control != JVMTI_ITERATION_ABORT;
1828 }
1829 }
1830
1831 // invoke advanced style heap root callback
1832 inline bool CallbackInvoker::invoke_advanced_heap_root_callback(jvmtiHeapReferenceKind ref_kind,
1833 oop obj) {
1834 AdvancedHeapWalkContext* context = advanced_context();
1835
1836 // check that callback is provided
1837 jvmtiHeapReferenceCallback cb = context->heap_reference_callback();
1838 if (cb == NULL) {
1839 return check_for_visit(obj);
1840 }
1841
1842 // apply class filter
1843 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
1844 return check_for_visit(obj);
1845 }
1846
1847 // setup the callback wrapper
1848 CallbackWrapper wrapper(tag_map(), obj);
1849
1850 // apply tag filter
1851 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
1852 wrapper.klass_tag(),
1853 context->heap_filter())) {
1854 return check_for_visit(obj);
1855 }
1856
1857 // for arrays we need the length, otherwise -1
1858 jint len = (jint)(obj->is_array() ? arrayOop(obj)->length() : -1);
1859
1860 // invoke the callback
1861 jint res = (*cb)(ref_kind,
1862 NULL, // referrer info
1863 wrapper.klass_tag(),
1864 0, // referrer_class_tag is 0 for heap root
1865 wrapper.obj_size(),
1866 wrapper.obj_tag_p(),
1867 NULL, // referrer_tag_p
1868 len,
1869 (void*)user_data());
1870 if (res & JVMTI_VISIT_ABORT) {
1871 return false;// referrer class tag
1872 }
1873 if (res & JVMTI_VISIT_OBJECTS) {
1874 check_for_visit(obj);
1875 }
1876 return true;
1877 }
1878
1879 // report a reference from a thread stack to an object
1880 inline bool CallbackInvoker::invoke_advanced_stack_ref_callback(jvmtiHeapReferenceKind ref_kind,
1881 jlong thread_tag,
1882 jlong tid,
1883 int depth,
1884 jmethodID method,
1885 jlocation bci,
1886 jint slot,
1887 oop obj) {
1888 AdvancedHeapWalkContext* context = advanced_context();
1889
1890 // check that callback is provider
1891 jvmtiHeapReferenceCallback cb = context->heap_reference_callback();
1892 if (cb == NULL) {
1893 return check_for_visit(obj);
1894 }
1895
1896 // apply class filter
1897 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
1898 return check_for_visit(obj);
1899 }
1900
1901 // setup the callback wrapper
1902 CallbackWrapper wrapper(tag_map(), obj);
1903
1904 // apply tag filter
1905 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
1906 wrapper.klass_tag(),
1907 context->heap_filter())) {
1908 return check_for_visit(obj);
1909 }
1910
1911 // setup the referrer info
1912 jvmtiHeapReferenceInfo reference_info;
1913 reference_info.stack_local.thread_tag = thread_tag;
1914 reference_info.stack_local.thread_id = tid;
1915 reference_info.stack_local.depth = depth;
1916 reference_info.stack_local.method = method;
1917 reference_info.stack_local.location = bci;
1918 reference_info.stack_local.slot = slot;
1919
1920 // for arrays we need the length, otherwise -1
1921 jint len = (jint)(obj->is_array() ? arrayOop(obj)->length() : -1);
1922
1923 // call into the agent
1924 int res = (*cb)(ref_kind,
1925 &reference_info,
1926 wrapper.klass_tag(),
1927 0, // referrer_class_tag is 0 for heap root (stack)
1928 wrapper.obj_size(),
1929 wrapper.obj_tag_p(),
1930 NULL, // referrer_tag is 0 for root
1931 len,
1932 (void*)user_data());
1933
1934 if (res & JVMTI_VISIT_ABORT) {
1935 return false;
1936 }
1937 if (res & JVMTI_VISIT_OBJECTS) {
1938 check_for_visit(obj);
1939 }
1940 return true;
1941 }
1942
1943 // This mask is used to pass reference_info to a jvmtiHeapReferenceCallback
1944 // only for ref_kinds defined by the JVM TI spec. Otherwise, NULL is passed.
1945 #define REF_INFO_MASK ((1 << JVMTI_HEAP_REFERENCE_FIELD) \
1946 | (1 << JVMTI_HEAP_REFERENCE_STATIC_FIELD) \
1947 | (1 << JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT) \
1948 | (1 << JVMTI_HEAP_REFERENCE_CONSTANT_POOL) \
1949 | (1 << JVMTI_HEAP_REFERENCE_STACK_LOCAL) \
1950 | (1 << JVMTI_HEAP_REFERENCE_JNI_LOCAL))
1951
1952 // invoke the object reference callback to report a reference
1953 inline bool CallbackInvoker::invoke_advanced_object_reference_callback(jvmtiHeapReferenceKind ref_kind,
1954 oop referrer,
1955 oop obj,
1956 jint index)
1957 {
1958 // field index is only valid field in reference_info
1959 static jvmtiHeapReferenceInfo reference_info = { 0 };
1960
1961 AdvancedHeapWalkContext* context = advanced_context();
1962
1963 // check that callback is provider
1964 jvmtiHeapReferenceCallback cb = context->heap_reference_callback();
1965 if (cb == NULL) {
1966 return check_for_visit(obj);
1967 }
1968
1969 // apply class filter
1970 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
1971 return check_for_visit(obj);
1972 }
1973
1974 // setup the callback wrapper
1975 TwoOopCallbackWrapper wrapper(tag_map(), referrer, obj);
1976
1977 // apply tag filter
1978 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
1979 wrapper.klass_tag(),
1980 context->heap_filter())) {
1981 return check_for_visit(obj);
1982 }
1983
1984 // field index is only valid field in reference_info
1985 reference_info.field.index = index;
1986
1987 // for arrays we need the length, otherwise -1
1988 jint len = (jint)(obj->is_array() ? arrayOop(obj)->length() : -1);
1989
1990 // invoke the callback
1991 int res = (*cb)(ref_kind,
1992 (REF_INFO_MASK & (1 << ref_kind)) ? &reference_info : NULL,
1993 wrapper.klass_tag(),
1994 wrapper.referrer_klass_tag(),
1995 wrapper.obj_size(),
1996 wrapper.obj_tag_p(),
1997 wrapper.referrer_tag_p(),
1998 len,
1999 (void*)user_data());
2000
2001 if (res & JVMTI_VISIT_ABORT) {
2002 return false;
2003 }
2004 if (res & JVMTI_VISIT_OBJECTS) {
2005 check_for_visit(obj);
2006 }
2007 return true;
2008 }
2009
2010 // report a "simple root"
2011 inline bool CallbackInvoker::report_simple_root(jvmtiHeapReferenceKind kind, oop obj) {
2012 assert(kind != JVMTI_HEAP_REFERENCE_STACK_LOCAL &&
2013 kind != JVMTI_HEAP_REFERENCE_JNI_LOCAL, "not a simple root");
2014
2015 if (is_basic_heap_walk()) {
2016 // map to old style root kind
2017 jvmtiHeapRootKind root_kind = toJvmtiHeapRootKind(kind);
2018 return invoke_basic_heap_root_callback(root_kind, obj);
2019 } else {
2020 assert(is_advanced_heap_walk(), "wrong heap walk type");
2021 return invoke_advanced_heap_root_callback(kind, obj);
2022 }
2023 }
2024
2025
2026 // invoke the primitive array values
2027 inline bool CallbackInvoker::report_primitive_array_values(oop obj) {
2028 assert(obj->is_typeArray(), "not a primitive array");
2029
2030 AdvancedHeapWalkContext* context = advanced_context();
2031 assert(context->array_primitive_value_callback() != NULL, "no callback");
2032
2033 // apply class filter
2034 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
2035 return true;
2036 }
2037
2038 CallbackWrapper wrapper(tag_map(), obj);
2039
2040 // apply tag filter
2041 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2042 wrapper.klass_tag(),
2043 context->heap_filter())) {
2044 return true;
2045 }
2046
2047 // invoke the callback
2048 int res = invoke_array_primitive_value_callback(context->array_primitive_value_callback(),
2049 &wrapper,
2050 obj,
2051 (void*)user_data());
2052 return (!(res & JVMTI_VISIT_ABORT));
2053 }
2054
2055 // invoke the string value callback
2056 inline bool CallbackInvoker::report_string_value(oop str) {
2057 assert(str->klass() == vmClasses::String_klass(), "not a string");
2058
2059 AdvancedHeapWalkContext* context = advanced_context();
2060 assert(context->string_primitive_value_callback() != NULL, "no callback");
2061
2062 // apply class filter
2063 if (is_filtered_by_klass_filter(str, context->klass_filter())) {
2064 return true;
2065 }
2066
2067 CallbackWrapper wrapper(tag_map(), str);
2068
2069 // apply tag filter
2070 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2071 wrapper.klass_tag(),
2072 context->heap_filter())) {
2073 return true;
2074 }
2075
2076 // invoke the callback
2077 int res = invoke_string_value_callback(context->string_primitive_value_callback(),
2078 &wrapper,
2079 str,
2080 (void*)user_data());
2081 return (!(res & JVMTI_VISIT_ABORT));
2082 }
2083
2084 // invoke the primitive field callback
2085 inline bool CallbackInvoker::report_primitive_field(jvmtiHeapReferenceKind ref_kind,
2086 oop obj,
2087 jint index,
2088 address addr,
2089 char type)
2090 {
2091 // for primitive fields only the index will be set
2092 static jvmtiHeapReferenceInfo reference_info = { 0 };
2093
2094 AdvancedHeapWalkContext* context = advanced_context();
2095 assert(context->primitive_field_callback() != NULL, "no callback");
2096
2097 // apply class filter
2098 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
2099 return true;
2100 }
2101
2102 CallbackWrapper wrapper(tag_map(), obj);
2103
2104 // apply tag filter
2105 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2106 wrapper.klass_tag(),
2107 context->heap_filter())) {
2108 return true;
2109 }
2110
2111 // the field index in the referrer
2112 reference_info.field.index = index;
2113
2114 // map the type
2115 jvmtiPrimitiveType value_type = (jvmtiPrimitiveType)type;
2116
2117 // setup the jvalue
2118 jvalue value;
2119 copy_to_jvalue(&value, addr, value_type);
2120
2121 jvmtiPrimitiveFieldCallback cb = context->primitive_field_callback();
2122 int res = (*cb)(ref_kind,
2123 &reference_info,
2124 wrapper.klass_tag(),
2125 wrapper.obj_tag_p(),
2126 value,
2127 value_type,
2128 (void*)user_data());
2129 return (!(res & JVMTI_VISIT_ABORT));
2130 }
2131
2132
2133 // instance field
2134 inline bool CallbackInvoker::report_primitive_instance_field(oop obj,
2135 jint index,
2136 address value,
2137 char type) {
2138 return report_primitive_field(JVMTI_HEAP_REFERENCE_FIELD,
2139 obj,
2140 index,
2141 value,
2142 type);
2143 }
2144
2145 // static field
2146 inline bool CallbackInvoker::report_primitive_static_field(oop obj,
2147 jint index,
2148 address value,
2149 char type) {
2150 return report_primitive_field(JVMTI_HEAP_REFERENCE_STATIC_FIELD,
2151 obj,
2152 index,
2153 value,
2154 type);
2155 }
2156
2157 // report a JNI local (root object) to the profiler
2158 inline bool CallbackInvoker::report_jni_local_root(jlong thread_tag, jlong tid, jint depth, jmethodID m, oop obj) {
2159 if (is_basic_heap_walk()) {
2160 return invoke_basic_stack_ref_callback(JVMTI_HEAP_ROOT_JNI_LOCAL,
2161 thread_tag,
2162 depth,
2163 m,
2164 -1,
2165 obj);
2166 } else {
2167 return invoke_advanced_stack_ref_callback(JVMTI_HEAP_REFERENCE_JNI_LOCAL,
2168 thread_tag, tid,
2169 depth,
2170 m,
2171 (jlocation)-1,
2172 -1,
2173 obj);
2174 }
2175 }
2176
2177
2178 // report a local (stack reference, root object)
2179 inline bool CallbackInvoker::report_stack_ref_root(jlong thread_tag,
2180 jlong tid,
2181 jint depth,
2182 jmethodID method,
2183 jlocation bci,
2184 jint slot,
2185 oop obj) {
2186 if (is_basic_heap_walk()) {
2187 return invoke_basic_stack_ref_callback(JVMTI_HEAP_ROOT_STACK_LOCAL,
2188 thread_tag,
2189 depth,
2190 method,
2191 slot,
2192 obj);
2193 } else {
2194 return invoke_advanced_stack_ref_callback(JVMTI_HEAP_REFERENCE_STACK_LOCAL,
2195 thread_tag,
2196 tid,
2197 depth,
2198 method,
2199 bci,
2200 slot,
2201 obj);
2202 }
2203 }
2204
2205 // report an object referencing a class.
2206 inline bool CallbackInvoker::report_class_reference(oop referrer, oop referree) {
2207 if (is_basic_heap_walk()) {
2208 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CLASS, referrer, referree, -1);
2209 } else {
2210 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_CLASS, referrer, referree, -1);
2211 }
2212 }
2213
2214 // report a class referencing its class loader.
2215 inline bool CallbackInvoker::report_class_loader_reference(oop referrer, oop referree) {
2216 if (is_basic_heap_walk()) {
2217 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CLASS_LOADER, referrer, referree, -1);
2218 } else {
2219 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_CLASS_LOADER, referrer, referree, -1);
2220 }
2221 }
2222
2223 // report a class referencing its signers.
2224 inline bool CallbackInvoker::report_signers_reference(oop referrer, oop referree) {
2225 if (is_basic_heap_walk()) {
2226 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_SIGNERS, referrer, referree, -1);
2227 } else {
2228 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_SIGNERS, referrer, referree, -1);
2229 }
2230 }
2231
2232 // report a class referencing its protection domain..
2233 inline bool CallbackInvoker::report_protection_domain_reference(oop referrer, oop referree) {
2234 if (is_basic_heap_walk()) {
2235 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_PROTECTION_DOMAIN, referrer, referree, -1);
2236 } else {
2237 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_PROTECTION_DOMAIN, referrer, referree, -1);
2238 }
2239 }
2240
2241 // report a class referencing its superclass.
2242 inline bool CallbackInvoker::report_superclass_reference(oop referrer, oop referree) {
2243 if (is_basic_heap_walk()) {
2244 // Send this to be consistent with past implementation
2245 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CLASS, referrer, referree, -1);
2246 } else {
2247 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_SUPERCLASS, referrer, referree, -1);
2248 }
2249 }
2250
2251 // report a class referencing one of its interfaces.
2252 inline bool CallbackInvoker::report_interface_reference(oop referrer, oop referree) {
2253 if (is_basic_heap_walk()) {
2254 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_INTERFACE, referrer, referree, -1);
2255 } else {
2256 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_INTERFACE, referrer, referree, -1);
2257 }
2258 }
2259
2260 // report a class referencing one of its static fields.
2261 inline bool CallbackInvoker::report_static_field_reference(oop referrer, oop referree, jint slot) {
2262 if (is_basic_heap_walk()) {
2263 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_STATIC_FIELD, referrer, referree, slot);
2264 } else {
2265 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_STATIC_FIELD, referrer, referree, slot);
2266 }
2267 }
2268
2269 // report an array referencing an element object
2270 inline bool CallbackInvoker::report_array_element_reference(oop referrer, oop referree, jint index) {
2271 if (is_basic_heap_walk()) {
2272 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_ARRAY_ELEMENT, referrer, referree, index);
2273 } else {
2274 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT, referrer, referree, index);
2275 }
2276 }
2277
2278 // report an object referencing an instance field object
2279 inline bool CallbackInvoker::report_field_reference(oop referrer, oop referree, jint slot) {
2280 if (is_basic_heap_walk()) {
2281 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_FIELD, referrer, referree, slot);
2282 } else {
2283 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_FIELD, referrer, referree, slot);
2284 }
2285 }
2286
2287 // report an array referencing an element object
2288 inline bool CallbackInvoker::report_constant_pool_reference(oop referrer, oop referree, jint index) {
2289 if (is_basic_heap_walk()) {
2290 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CONSTANT_POOL, referrer, referree, index);
2291 } else {
2292 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_CONSTANT_POOL, referrer, referree, index);
2293 }
2294 }
2295
2296 // A supporting closure used to process simple roots
2297 class SimpleRootsClosure : public OopClosure {
2298 private:
2299 jvmtiHeapReferenceKind _kind;
2300 bool _continue;
2301
2302 jvmtiHeapReferenceKind root_kind() { return _kind; }
2303
2304 public:
2305 void set_kind(jvmtiHeapReferenceKind kind) {
2306 _kind = kind;
2307 _continue = true;
2308 }
2309
2310 inline bool stopped() {
2311 return !_continue;
2312 }
2313
2314 void do_oop(oop* obj_p) {
2315 // iteration has terminated
2316 if (stopped()) {
2317 return;
2318 }
2319
2320 oop o = NativeAccess<AS_NO_KEEPALIVE>::oop_load(obj_p);
2321 // ignore null
2322 if (o == NULL) {
2323 return;
2324 }
2325
2326 assert(Universe::heap()->is_in(o), "should be impossible");
2327
2328 jvmtiHeapReferenceKind kind = root_kind();
2329
2330 // invoke the callback
2331 _continue = CallbackInvoker::report_simple_root(kind, o);
2332
2333 }
2334 virtual void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }
2335 };
2336
2337 // A supporting closure used to process JNI locals
2338 class JNILocalRootsClosure : public OopClosure {
2339 private:
2340 jlong _thread_tag;
2341 jlong _tid;
2342 jint _depth;
2343 jmethodID _method;
2344 bool _continue;
2345 public:
2346 void set_context(jlong thread_tag, jlong tid, jint depth, jmethodID method) {
2347 _thread_tag = thread_tag;
2348 _tid = tid;
2349 _depth = depth;
2350 _method = method;
2351 _continue = true;
2352 }
2353
2354 inline bool stopped() {
2355 return !_continue;
2356 }
2357
2358 void do_oop(oop* obj_p) {
2359 // iteration has terminated
2360 if (stopped()) {
2361 return;
2362 }
2363
2364 oop o = *obj_p;
2365 // ignore null
2366 if (o == NULL) {
2367 return;
2368 }
2369
2370 // invoke the callback
2371 _continue = CallbackInvoker::report_jni_local_root(_thread_tag, _tid, _depth, _method, o);
2372 }
2373 virtual void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }
2374 };
2375
2376
2377 // A VM operation to iterate over objects that are reachable from
2378 // a set of roots or an initial object.
2379 //
2380 // For VM_HeapWalkOperation the set of roots used is :-
2381 //
2382 // - All JNI global references
2383 // - All inflated monitors
2384 // - All classes loaded by the boot class loader (or all classes
2385 // in the event that class unloading is disabled)
2386 // - All java threads
2387 // - For each java thread then all locals and JNI local references
2388 // on the thread's execution stack
2389 // - All visible/explainable objects from Universes::oops_do
2390 //
2391 class VM_HeapWalkOperation: public VM_Operation {
2392 private:
2393 enum {
2394 initial_visit_stack_size = 4000
2395 };
2396
2397 bool _is_advanced_heap_walk; // indicates FollowReferences
2398 JvmtiTagMap* _tag_map;
2399 Handle _initial_object;
2400 GrowableArray<oop>* _visit_stack; // the visit stack
2401
2402 // Dead object tags in JvmtiTagMap
2403 GrowableArray<jlong>* _dead_objects;
2404
2405 bool _following_object_refs; // are we following object references
2406
2407 bool _reporting_primitive_fields; // optional reporting
2408 bool _reporting_primitive_array_values;
2409 bool _reporting_string_values;
2410
2411 GrowableArray<oop>* create_visit_stack() {
2412 return new (ResourceObj::C_HEAP, mtServiceability) GrowableArray<oop>(initial_visit_stack_size, mtServiceability);
2413 }
2414
2415 // accessors
2416 bool is_advanced_heap_walk() const { return _is_advanced_heap_walk; }
2417 JvmtiTagMap* tag_map() const { return _tag_map; }
2418 Handle initial_object() const { return _initial_object; }
2419
2420 bool is_following_references() const { return _following_object_refs; }
2421
2422 bool is_reporting_primitive_fields() const { return _reporting_primitive_fields; }
2423 bool is_reporting_primitive_array_values() const { return _reporting_primitive_array_values; }
2424 bool is_reporting_string_values() const { return _reporting_string_values; }
2425
2426 GrowableArray<oop>* visit_stack() const { return _visit_stack; }
2427
2428 // iterate over the various object types
2429 inline bool iterate_over_array(oop o);
2430 inline bool iterate_over_type_array(oop o);
2431 inline bool iterate_over_class(oop o);
2432 inline bool iterate_over_object(oop o);
2433
2434 // root collection
2435 inline bool collect_simple_roots();
2436 inline bool collect_stack_roots();
2437 inline bool collect_stack_roots(JavaThread* java_thread, JNILocalRootsClosure* blk);
2438
2439 // visit an object
2440 inline bool visit(oop o);
2441
2442 public:
2443 VM_HeapWalkOperation(JvmtiTagMap* tag_map,
2444 Handle initial_object,
2445 BasicHeapWalkContext callbacks,
2446 const void* user_data,
2447 GrowableArray<jlong>* objects);
2448
2449 VM_HeapWalkOperation(JvmtiTagMap* tag_map,
2450 Handle initial_object,
2451 AdvancedHeapWalkContext callbacks,
2452 const void* user_data,
2453 GrowableArray<jlong>* objects);
2454
2455 ~VM_HeapWalkOperation();
2456
2457 VMOp_Type type() const { return VMOp_HeapWalkOperation; }
2458 void doit();
2459 };
2460
2461
2462 VM_HeapWalkOperation::VM_HeapWalkOperation(JvmtiTagMap* tag_map,
2463 Handle initial_object,
2464 BasicHeapWalkContext callbacks,
2465 const void* user_data,
2466 GrowableArray<jlong>* objects) {
2467 _is_advanced_heap_walk = false;
2468 _tag_map = tag_map;
2469 _initial_object = initial_object;
2470 _following_object_refs = (callbacks.object_ref_callback() != NULL);
2471 _reporting_primitive_fields = false;
2472 _reporting_primitive_array_values = false;
2473 _reporting_string_values = false;
2474 _visit_stack = create_visit_stack();
2475 _dead_objects = objects;
2476
2477
2478 CallbackInvoker::initialize_for_basic_heap_walk(tag_map, _visit_stack, user_data, callbacks);
2479 }
2480
2481 VM_HeapWalkOperation::VM_HeapWalkOperation(JvmtiTagMap* tag_map,
2482 Handle initial_object,
2483 AdvancedHeapWalkContext callbacks,
2484 const void* user_data,
2485 GrowableArray<jlong>* objects) {
2486 _is_advanced_heap_walk = true;
2487 _tag_map = tag_map;
2488 _initial_object = initial_object;
2489 _following_object_refs = true;
2490 _reporting_primitive_fields = (callbacks.primitive_field_callback() != NULL);;
2491 _reporting_primitive_array_values = (callbacks.array_primitive_value_callback() != NULL);;
2492 _reporting_string_values = (callbacks.string_primitive_value_callback() != NULL);;
2493 _visit_stack = create_visit_stack();
2494 _dead_objects = objects;
2495
2496 CallbackInvoker::initialize_for_advanced_heap_walk(tag_map, _visit_stack, user_data, callbacks);
2497 }
2498
2499 VM_HeapWalkOperation::~VM_HeapWalkOperation() {
2500 if (_following_object_refs) {
2501 assert(_visit_stack != NULL, "checking");
2502 delete _visit_stack;
2503 _visit_stack = NULL;
2504 }
2505 }
2506
2507 // an array references its class and has a reference to
2508 // each element in the array
2509 inline bool VM_HeapWalkOperation::iterate_over_array(oop o) {
2510 objArrayOop array = objArrayOop(o);
2511
2512 // array reference to its class
2513 oop mirror = ObjArrayKlass::cast(array->klass())->java_mirror();
2514 if (!CallbackInvoker::report_class_reference(o, mirror)) {
2515 return false;
2516 }
2517
2518 // iterate over the array and report each reference to a
2519 // non-null element
2520 for (int index=0; index<array->length(); index++) {
2521 oop elem = array->obj_at(index);
2522 if (elem == NULL) {
2523 continue;
2524 }
2525
2526 // report the array reference o[index] = elem
2527 if (!CallbackInvoker::report_array_element_reference(o, elem, index)) {
2528 return false;
2529 }
2530 }
2531 return true;
2532 }
2533
2534 // a type array references its class
2535 inline bool VM_HeapWalkOperation::iterate_over_type_array(oop o) {
2536 Klass* k = o->klass();
2537 oop mirror = k->java_mirror();
2538 if (!CallbackInvoker::report_class_reference(o, mirror)) {
2539 return false;
2540 }
2541
2542 // report the array contents if required
2543 if (is_reporting_primitive_array_values()) {
2544 if (!CallbackInvoker::report_primitive_array_values(o)) {
2545 return false;
2546 }
2547 }
2548 return true;
2549 }
2550
2551 #ifdef ASSERT
2552 // verify that a static oop field is in range
2553 static inline bool verify_static_oop(InstanceKlass* ik,
2554 oop mirror, int offset) {
2555 address obj_p = cast_from_oop<address>(mirror) + offset;
2556 address start = (address)InstanceMirrorKlass::start_of_static_fields(mirror);
2557 address end = start + (java_lang_Class::static_oop_field_count(mirror) * heapOopSize);
2558 assert(end >= start, "sanity check");
2559
2560 if (obj_p >= start && obj_p < end) {
2561 return true;
2562 } else {
2563 return false;
2564 }
2565 }
2566 #endif // #ifdef ASSERT
2567
2568 // a class references its super class, interfaces, class loader, ...
2569 // and finally its static fields
2570 inline bool VM_HeapWalkOperation::iterate_over_class(oop java_class) {
2571 int i;
2572 Klass* klass = java_lang_Class::as_Klass(java_class);
2573
2574 if (klass->is_instance_klass()) {
2575 InstanceKlass* ik = InstanceKlass::cast(klass);
2576
2577 // Ignore the class if it hasn't been initialized yet
2578 if (!ik->is_linked()) {
2579 return true;
2580 }
2581
2582 // get the java mirror
2583 oop mirror = klass->java_mirror();
2584
2585 // super (only if something more interesting than java.lang.Object)
2586 InstanceKlass* java_super = ik->java_super();
2587 if (java_super != NULL && java_super != vmClasses::Object_klass()) {
2588 oop super = java_super->java_mirror();
2589 if (!CallbackInvoker::report_superclass_reference(mirror, super)) {
2590 return false;
2591 }
2592 }
2593
2594 // class loader
2595 oop cl = ik->class_loader();
2596 if (cl != NULL) {
2597 if (!CallbackInvoker::report_class_loader_reference(mirror, cl)) {
2598 return false;
2599 }
2600 }
2601
2602 // protection domain
2603 oop pd = ik->protection_domain();
2604 if (pd != NULL) {
2605 if (!CallbackInvoker::report_protection_domain_reference(mirror, pd)) {
2606 return false;
2607 }
2608 }
2609
2610 // signers
2611 oop signers = ik->signers();
2612 if (signers != NULL) {
2613 if (!CallbackInvoker::report_signers_reference(mirror, signers)) {
2614 return false;
2615 }
2616 }
2617
2618 // references from the constant pool
2619 {
2620 ConstantPool* pool = ik->constants();
2621 for (int i = 1; i < pool->length(); i++) {
2622 constantTag tag = pool->tag_at(i).value();
2623 if (tag.is_string() || tag.is_klass() || tag.is_unresolved_klass()) {
2624 oop entry;
2625 if (tag.is_string()) {
2626 entry = pool->resolved_string_at(i);
2627 // If the entry is non-null it is resolved.
2628 if (entry == NULL) {
2629 continue;
2630 }
2631 } else if (tag.is_klass()) {
2632 entry = pool->resolved_klass_at(i)->java_mirror();
2633 } else {
2634 // Code generated by JIT compilers might not resolve constant
2635 // pool entries. Treat them as resolved if they are loaded.
2636 assert(tag.is_unresolved_klass(), "must be");
2637 constantPoolHandle cp(Thread::current(), pool);
2638 Klass* klass = ConstantPool::klass_at_if_loaded(cp, i);
2639 if (klass == NULL) {
2640 continue;
2641 }
2642 entry = klass->java_mirror();
2643 }
2644 if (!CallbackInvoker::report_constant_pool_reference(mirror, entry, (jint)i)) {
2645 return false;
2646 }
2647 }
2648 }
2649 }
2650
2651 // interfaces
2652 // (These will already have been reported as references from the constant pool
2653 // but are specified by IterateOverReachableObjects and must be reported).
2654 Array<InstanceKlass*>* interfaces = ik->local_interfaces();
2655 for (i = 0; i < interfaces->length(); i++) {
2656 oop interf = interfaces->at(i)->java_mirror();
2657 if (interf == NULL) {
2658 continue;
2659 }
2660 if (!CallbackInvoker::report_interface_reference(mirror, interf)) {
2661 return false;
2662 }
2663 }
2664
2665 // iterate over the static fields
2666
2667 ClassFieldMap* field_map = ClassFieldMap::create_map_of_static_fields(klass);
2668 for (i=0; i<field_map->field_count(); i++) {
2669 ClassFieldDescriptor* field = field_map->field_at(i);
2670 char type = field->field_type();
2671 if (!is_primitive_field_type(type)) {
2672 oop fld_o = mirror->obj_field(field->field_offset());
2673 assert(verify_static_oop(ik, mirror, field->field_offset()), "sanity check");
2674 if (fld_o != NULL) {
2675 int slot = field->field_index();
2676 if (!CallbackInvoker::report_static_field_reference(mirror, fld_o, slot)) {
2677 delete field_map;
2678 return false;
2679 }
2680 }
2681 } else {
2682 if (is_reporting_primitive_fields()) {
2683 address addr = cast_from_oop<address>(mirror) + field->field_offset();
2684 int slot = field->field_index();
2685 if (!CallbackInvoker::report_primitive_static_field(mirror, slot, addr, type)) {
2686 delete field_map;
2687 return false;
2688 }
2689 }
2690 }
2691 }
2692 delete field_map;
2693
2694 return true;
2695 }
2696
2697 return true;
2698 }
2699
2700 // an object references a class and its instance fields
2701 // (static fields are ignored here as we report these as
2702 // references from the class).
2703 inline bool VM_HeapWalkOperation::iterate_over_object(oop o) {
2704 // reference to the class
2705 if (!CallbackInvoker::report_class_reference(o, o->klass()->java_mirror())) {
2706 return false;
2707 }
2708
2709 // iterate over instance fields
2710 ClassFieldMap* field_map = JvmtiCachedClassFieldMap::get_map_of_instance_fields(o);
2711 for (int i=0; i<field_map->field_count(); i++) {
2712 ClassFieldDescriptor* field = field_map->field_at(i);
2713 char type = field->field_type();
2714 if (!is_primitive_field_type(type)) {
2715 oop fld_o = o->obj_field_access<AS_NO_KEEPALIVE | ON_UNKNOWN_OOP_REF>(field->field_offset());
2716 // ignore any objects that aren't visible to profiler
2717 if (fld_o != NULL) {
2718 assert(Universe::heap()->is_in(fld_o), "unsafe code should not "
2719 "have references to Klass* anymore");
2720 int slot = field->field_index();
2721 if (!CallbackInvoker::report_field_reference(o, fld_o, slot)) {
2722 return false;
2723 }
2724 }
2725 } else {
2726 if (is_reporting_primitive_fields()) {
2727 // primitive instance field
2728 address addr = cast_from_oop<address>(o) + field->field_offset();
2729 int slot = field->field_index();
2730 if (!CallbackInvoker::report_primitive_instance_field(o, slot, addr, type)) {
2731 return false;
2732 }
2733 }
2734 }
2735 }
2736
2737 // if the object is a java.lang.String
2738 if (is_reporting_string_values() &&
2739 o->klass() == vmClasses::String_klass()) {
2740 if (!CallbackInvoker::report_string_value(o)) {
2741 return false;
2742 }
2743 }
2744 return true;
2745 }
2746
2747
2748 // Collects all simple (non-stack) roots except for threads;
2749 // threads are handled in collect_stack_roots() as an optimization.
2750 // if there's a heap root callback provided then the callback is
2751 // invoked for each simple root.
2752 // if an object reference callback is provided then all simple
2753 // roots are pushed onto the marking stack so that they can be
2754 // processed later
2755 //
2756 inline bool VM_HeapWalkOperation::collect_simple_roots() {
2757 SimpleRootsClosure blk;
2758
2759 // JNI globals
2760 blk.set_kind(JVMTI_HEAP_REFERENCE_JNI_GLOBAL);
2761 JNIHandles::oops_do(&blk);
2762 if (blk.stopped()) {
2763 return false;
2764 }
2765
2766 // Preloaded classes and loader from the system dictionary
2767 blk.set_kind(JVMTI_HEAP_REFERENCE_SYSTEM_CLASS);
2768 CLDToOopClosure cld_closure(&blk, false);
2769 ClassLoaderDataGraph::always_strong_cld_do(&cld_closure);
2770 if (blk.stopped()) {
2771 return false;
2772 }
2773
2774 // threads are now handled in collect_stack_roots()
2775
2776 // Other kinds of roots maintained by HotSpot
2777 // Many of these won't be visible but others (such as instances of important
2778 // exceptions) will be visible.
2779 blk.set_kind(JVMTI_HEAP_REFERENCE_OTHER);
2780 Universe::vm_global()->oops_do(&blk);
2781 if (blk.stopped()) {
2782 return false;
2783 }
2784
2785 return true;
2786 }
2787
2788 // Walk the stack of a given thread and find all references (locals
2789 // and JNI calls) and report these as stack references
2790 inline bool VM_HeapWalkOperation::collect_stack_roots(JavaThread* java_thread,
2791 JNILocalRootsClosure* blk)
2792 {
2793 oop threadObj = java_thread->threadObj();
2794 assert(threadObj != NULL, "sanity check");
2795
2796 // only need to get the thread's tag once per thread
2797 jlong thread_tag = tag_for(_tag_map, threadObj);
2798
2799 // also need the thread id
2800 jlong tid = java_lang_Thread::thread_id(threadObj);
2801
2802
2803 if (java_thread->has_last_Java_frame()) {
2804
2805 // vframes are resource allocated
2806 Thread* current_thread = Thread::current();
2807 ResourceMark rm(current_thread);
2808 HandleMark hm(current_thread);
2809
2810 RegisterMap reg_map(java_thread);
2811 frame f = java_thread->last_frame();
2812 vframe* vf = vframe::new_vframe(&f, ®_map, java_thread);
2813
2814 bool is_top_frame = true;
2815 int depth = 0;
2816 frame* last_entry_frame = NULL;
2817
2818 while (vf != NULL) {
2819 if (vf->is_java_frame()) {
2820
2821 // java frame (interpreted, compiled, ...)
2822 javaVFrame *jvf = javaVFrame::cast(vf);
2823
2824 // the jmethodID
2825 jmethodID method = jvf->method()->jmethod_id();
2826
2827 if (!(jvf->method()->is_native())) {
2828 jlocation bci = (jlocation)jvf->bci();
2829 StackValueCollection* locals = jvf->locals();
2830 for (int slot=0; slot<locals->size(); slot++) {
2831 if (locals->at(slot)->type() == T_OBJECT) {
2832 oop o = locals->obj_at(slot)();
2833 if (o == NULL) {
2834 continue;
2835 }
2836
2837 // stack reference
2838 if (!CallbackInvoker::report_stack_ref_root(thread_tag, tid, depth, method,
2839 bci, slot, o)) {
2840 return false;
2841 }
2842 }
2843 }
2844
2845 StackValueCollection* exprs = jvf->expressions();
2846 for (int index=0; index < exprs->size(); index++) {
2847 if (exprs->at(index)->type() == T_OBJECT) {
2848 oop o = exprs->obj_at(index)();
2849 if (o == NULL) {
2850 continue;
2851 }
2852
2853 // stack reference
2854 if (!CallbackInvoker::report_stack_ref_root(thread_tag, tid, depth, method,
2855 bci, locals->size() + index, o)) {
2856 return false;
2857 }
2858 }
2859 }
2860
2861 // Follow oops from compiled nmethod
2862 if (jvf->cb() != NULL && jvf->cb()->is_nmethod()) {
2863 blk->set_context(thread_tag, tid, depth, method);
2864 jvf->cb()->as_nmethod()->oops_do(blk);
2865 }
2866 } else {
2867 blk->set_context(thread_tag, tid, depth, method);
2868 if (is_top_frame) {
2869 // JNI locals for the top frame.
2870 java_thread->active_handles()->oops_do(blk);
2871 } else {
2872 if (last_entry_frame != NULL) {
2873 // JNI locals for the entry frame
2874 assert(last_entry_frame->is_entry_frame(), "checking");
2875 last_entry_frame->entry_frame_call_wrapper()->handles()->oops_do(blk);
2876 }
2877 }
2878 }
2879 last_entry_frame = NULL;
2880 depth++;
2881 } else {
2882 // externalVFrame - for an entry frame then we report the JNI locals
2883 // when we find the corresponding javaVFrame
2884 frame* fr = vf->frame_pointer();
2885 assert(fr != NULL, "sanity check");
2886 if (fr->is_entry_frame()) {
2887 last_entry_frame = fr;
2888 }
2889 }
2890
2891 vf = vf->sender();
2892 is_top_frame = false;
2893 }
2894 } else {
2895 // no last java frame but there may be JNI locals
2896 blk->set_context(thread_tag, tid, 0, (jmethodID)NULL);
2897 java_thread->active_handles()->oops_do(blk);
2898 }
2899 return true;
2900 }
2901
2902
2903 // Collects the simple roots for all threads and collects all
2904 // stack roots - for each thread it walks the execution
2905 // stack to find all references and local JNI refs.
2906 inline bool VM_HeapWalkOperation::collect_stack_roots() {
2907 JNILocalRootsClosure blk;
2908 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thread = jtiwh.next(); ) {
2909 oop threadObj = thread->threadObj();
2910 if (threadObj != NULL && !thread->is_exiting() && !thread->is_hidden_from_external_view()) {
2911 // Collect the simple root for this thread before we
2912 // collect its stack roots
2913 if (!CallbackInvoker::report_simple_root(JVMTI_HEAP_REFERENCE_THREAD,
2914 threadObj)) {
2915 return false;
2916 }
2917 if (!collect_stack_roots(thread, &blk)) {
2918 return false;
2919 }
2920 }
2921 }
2922 return true;
2923 }
2924
2925 // visit an object
2926 // first mark the object as visited
2927 // second get all the outbound references from this object (in other words, all
2928 // the objects referenced by this object).
2929 //
2930 bool VM_HeapWalkOperation::visit(oop o) {
2931 // mark object as visited
2932 assert(!ObjectMarker::visited(o), "can't visit same object more than once");
2933 ObjectMarker::mark(o);
2934
2935 // instance
2936 if (o->is_instance()) {
2937 if (o->klass() == vmClasses::Class_klass()) {
2938 if (!java_lang_Class::is_primitive(o)) {
2939 // a java.lang.Class
2940 return iterate_over_class(o);
2941 }
2942 } else {
2943 return iterate_over_object(o);
2944 }
2945 }
2946
2947 // object array
2948 if (o->is_objArray()) {
2949 return iterate_over_array(o);
2950 }
2951
2952 // type array
2953 if (o->is_typeArray()) {
2954 return iterate_over_type_array(o);
2955 }
2956
2957 return true;
2958 }
2959
2960 void VM_HeapWalkOperation::doit() {
2961 ResourceMark rm;
2962 ObjectMarkerController marker;
2963 ClassFieldMapCacheMark cm;
2964
2965 JvmtiTagMap::check_hashmaps_for_heapwalk(_dead_objects);
2966
2967 assert(visit_stack()->is_empty(), "visit stack must be empty");
2968
2969 // the heap walk starts with an initial object or the heap roots
2970 if (initial_object().is_null()) {
2971 // If either collect_stack_roots() or collect_simple_roots()
2972 // returns false at this point, then there are no mark bits
2973 // to reset.
2974 ObjectMarker::set_needs_reset(false);
2975
2976 // Calling collect_stack_roots() before collect_simple_roots()
2977 // can result in a big performance boost for an agent that is
2978 // focused on analyzing references in the thread stacks.
2979 if (!collect_stack_roots()) return;
2980
2981 if (!collect_simple_roots()) return;
2982
2983 // no early return so enable heap traversal to reset the mark bits
2984 ObjectMarker::set_needs_reset(true);
2985 } else {
2986 visit_stack()->push(initial_object()());
2987 }
2988
2989 // object references required
2990 if (is_following_references()) {
2991
2992 // visit each object until all reachable objects have been
2993 // visited or the callback asked to terminate the iteration.
2994 while (!visit_stack()->is_empty()) {
2995 oop o = visit_stack()->pop();
2996 if (!ObjectMarker::visited(o)) {
2997 if (!visit(o)) {
2998 break;
2999 }
3000 }
3001 }
3002 }
3003 }
3004
3005 // iterate over all objects that are reachable from a set of roots
3006 void JvmtiTagMap::iterate_over_reachable_objects(jvmtiHeapRootCallback heap_root_callback,
3007 jvmtiStackReferenceCallback stack_ref_callback,
3008 jvmtiObjectReferenceCallback object_ref_callback,
3009 const void* user_data) {
3010 JavaThread* jt = JavaThread::current();
3011 EscapeBarrier eb(true, jt);
3012 eb.deoptimize_objects_all_threads();
3013 Arena dead_object_arena(mtServiceability);
3014 GrowableArray<jlong> dead_objects(&dead_object_arena, 10, 0, 0);
3015 {
3016 MutexLocker ml(Heap_lock);
3017 BasicHeapWalkContext context(heap_root_callback, stack_ref_callback, object_ref_callback);
3018 VM_HeapWalkOperation op(this, Handle(), context, user_data, &dead_objects);
3019 VMThread::execute(&op);
3020 }
3021 // Post events outside of Heap_lock
3022 post_dead_objects(&dead_objects);
3023 }
3024
3025 // iterate over all objects that are reachable from a given object
3026 void JvmtiTagMap::iterate_over_objects_reachable_from_object(jobject object,
3027 jvmtiObjectReferenceCallback object_ref_callback,
3028 const void* user_data) {
3029 oop obj = JNIHandles::resolve(object);
3030 Handle initial_object(Thread::current(), obj);
3031
3032 Arena dead_object_arena(mtServiceability);
3033 GrowableArray<jlong> dead_objects(&dead_object_arena, 10, 0, 0);
3034 {
3035 MutexLocker ml(Heap_lock);
3036 BasicHeapWalkContext context(NULL, NULL, object_ref_callback);
3037 VM_HeapWalkOperation op(this, initial_object, context, user_data, &dead_objects);
3038 VMThread::execute(&op);
3039 }
3040 // Post events outside of Heap_lock
3041 post_dead_objects(&dead_objects);
3042 }
3043
3044 // follow references from an initial object or the GC roots
3045 void JvmtiTagMap::follow_references(jint heap_filter,
3046 Klass* klass,
3047 jobject object,
3048 const jvmtiHeapCallbacks* callbacks,
3049 const void* user_data)
3050 {
3051 oop obj = JNIHandles::resolve(object);
3052 JavaThread* jt = JavaThread::current();
3053 Handle initial_object(jt, obj);
3054 // EA based optimizations that are tagged or reachable from initial_object are already reverted.
3055 EscapeBarrier eb(initial_object.is_null() &&
3056 !(heap_filter & JVMTI_HEAP_FILTER_UNTAGGED),
3057 jt);
3058 eb.deoptimize_objects_all_threads();
3059
3060 Arena dead_object_arena(mtServiceability);
3061 GrowableArray<jlong> dead_objects(&dead_object_arena, 10, 0, 0);
3062 {
3063 MutexLocker ml(Heap_lock);
3064 AdvancedHeapWalkContext context(heap_filter, klass, callbacks);
3065 VM_HeapWalkOperation op(this, initial_object, context, user_data, &dead_objects);
3066 VMThread::execute(&op);
3067 }
3068 // Post events outside of Heap_lock
3069 post_dead_objects(&dead_objects);
3070 }
3071
3072 // Concurrent GC needs to call this in relocation pause, so after the objects are moved
3073 // and have their new addresses, the table can be rehashed.
3074 void JvmtiTagMap::set_needs_rehashing() {
3075 assert(SafepointSynchronize::is_at_safepoint(), "called in gc pause");
3076 assert(Thread::current()->is_VM_thread(), "should be the VM thread");
3077
3078 JvmtiEnvIterator it;
3079 for (JvmtiEnv* env = it.first(); env != NULL; env = it.next(env)) {
3080 JvmtiTagMap* tag_map = env->tag_map_acquire();
3081 if (tag_map != NULL) {
3082 tag_map->_needs_rehashing = true;
3083 }
3084 }
3085 }
3086
3087 // Verify gc_notification follows set_needs_cleaning.
3088 DEBUG_ONLY(static bool notified_needs_cleaning = false;)
3089
3090 void JvmtiTagMap::set_needs_cleaning() {
3091 assert(SafepointSynchronize::is_at_safepoint(), "called in gc pause");
3092 assert(Thread::current()->is_VM_thread(), "should be the VM thread");
3093 // Can't assert !notified_needs_cleaning; a partial GC might be upgraded
3094 // to a full GC and do this twice without intervening gc_notification.
3095 DEBUG_ONLY(notified_needs_cleaning = true;)
3096
3097 JvmtiEnvIterator it;
3098 for (JvmtiEnv* env = it.first(); env != NULL; env = it.next(env)) {
3099 JvmtiTagMap* tag_map = env->tag_map_acquire();
3100 if (tag_map != NULL) {
3101 tag_map->_needs_cleaning = !tag_map->is_empty();
3102 }
3103 }
3104 }
3105
3106 void JvmtiTagMap::gc_notification(size_t num_dead_entries) {
3107 assert(notified_needs_cleaning, "missing GC notification");
3108 DEBUG_ONLY(notified_needs_cleaning = false;)
3109
3110 // Notify ServiceThread if there's work to do.
3111 {
3112 MonitorLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
3113 _has_object_free_events = (num_dead_entries != 0);
3114 if (_has_object_free_events) ml.notify_all();
3115 }
3116
3117 // If no dead entries then cancel cleaning requests.
3118 if (num_dead_entries == 0) {
3119 JvmtiEnvIterator it;
3120 for (JvmtiEnv* env = it.first(); env != NULL; env = it.next(env)) {
3121 JvmtiTagMap* tag_map = env->tag_map_acquire();
3122 if (tag_map != NULL) {
3123 MutexLocker ml (tag_map->lock(), Mutex::_no_safepoint_check_flag);
3124 tag_map->_needs_cleaning = false;
3125 }
3126 }
3127 }
3128 }
3129
3130 // Used by ServiceThread to discover there is work to do.
3131 bool JvmtiTagMap::has_object_free_events_and_reset() {
3132 assert_lock_strong(Service_lock);
3133 bool result = _has_object_free_events;
3134 _has_object_free_events = false;
3135 return result;
3136 }
3137
3138 // Used by ServiceThread to clean up tagmaps.
3139 void JvmtiTagMap::flush_all_object_free_events() {
3140 JavaThread* thread = JavaThread::current();
3141 JvmtiEnvIterator it;
3142 for (JvmtiEnv* env = it.first(); env != NULL; env = it.next(env)) {
3143 JvmtiTagMap* tag_map = env->tag_map_acquire();
3144 if (tag_map != NULL) {
3145 tag_map->flush_object_free_events();
3146 ThreadBlockInVM tbiv(thread); // Be safepoint-polite while looping.
3147 }
3148 }
3149 }