1 /*
2 * Copyright (c) 2003, 2018, 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/javaClasses.inline.hpp"
27 #include "classfile/symbolTable.hpp"
28 #include "classfile/systemDictionary.hpp"
29 #include "classfile/vmSymbols.hpp"
30 #include "code/codeCache.hpp"
31 #include "jvmtifiles/jvmtiEnv.hpp"
32 #include "memory/resourceArea.hpp"
33 #include "oops/access.inline.hpp"
34 #include "oops/arrayOop.inline.hpp"
35 #include "oops/instanceMirrorKlass.hpp"
36 #include "oops/objArrayKlass.hpp"
37 #include "oops/objArrayOop.inline.hpp"
38 #include "oops/oop.inline.hpp"
39 #include "oops/typeArrayOop.inline.hpp"
40 #include "prims/jvmtiEventController.hpp"
41 #include "prims/jvmtiEventController.inline.hpp"
42 #include "prims/jvmtiExport.hpp"
43 #include "prims/jvmtiImpl.hpp"
44 #include "prims/jvmtiTagMap.hpp"
45 #include "runtime/biasedLocking.hpp"
46 #include "runtime/javaCalls.hpp"
47 #include "runtime/jniHandles.inline.hpp"
48 #include "runtime/mutex.hpp"
49 #include "runtime/mutexLocker.hpp"
50 #include "runtime/reflectionUtils.hpp"
51 #include "runtime/thread.inline.hpp"
52 #include "runtime/threadSMR.hpp"
53 #include "runtime/vframe.hpp"
54 #include "runtime/vmThread.hpp"
55 #include "runtime/vm_operations.hpp"
56 #include "services/serviceUtil.hpp"
57 #include "utilities/macros.hpp"
58
59 // JvmtiTagHashmapEntry
60 //
61 // Each entry encapsulates a reference to the tagged object
62 // and the tag value. In addition an entry includes a next pointer which
63 // is used to chain entries together.
64
65 class JvmtiTagHashmapEntry : public CHeapObj<mtInternal> {
66 private:
67 friend class JvmtiTagMap;
68
69 oop _object; // tagged object
70 jlong _tag; // the tag
71 JvmtiTagHashmapEntry* _next; // next on the list
72
73 inline void init(oop object, jlong tag) {
74 _object = object;
75 _tag = tag;
76 _next = NULL;
77 }
78
79 // constructor
80 JvmtiTagHashmapEntry(oop object, jlong tag) { init(object, tag); }
81
82 public:
83
84 // accessor methods
85 inline oop* object_addr() { return &_object; }
86 inline oop object() { return RootAccess<ON_PHANTOM_OOP_REF>::oop_load(object_addr()); }
87 // Peek at the object without keeping it alive. The returned object must be
88 // kept alive using a normal access if it leaks out of a thread transition from VM.
89 inline oop object_peek() {
90 return RootAccess<ON_PHANTOM_OOP_REF | AS_NO_KEEPALIVE>::oop_load(object_addr());
91 }
92 inline jlong tag() const { return _tag; }
93
94 inline void set_tag(jlong tag) {
95 assert(tag != 0, "can't be zero");
96 _tag = tag;
97 }
98
99 inline bool equals(oop object) {
100 return object == object_peek();
101 }
102
103 inline JvmtiTagHashmapEntry* next() const { return _next; }
104 inline void set_next(JvmtiTagHashmapEntry* next) { _next = next; }
105 };
106
107
108 // JvmtiTagHashmap
109 //
110 // A hashmap is essentially a table of pointers to entries. Entries
111 // are hashed to a location, or position in the table, and then
112 // chained from that location. The "key" for hashing is address of
113 // the object, or oop. The "value" is the tag value.
114 //
115 // A hashmap maintains a count of the number entries in the hashmap
116 // and resizes if the number of entries exceeds a given threshold.
117 // The threshold is specified as a percentage of the size - for
118 // example a threshold of 0.75 will trigger the hashmap to resize
119 // if the number of entries is >75% of table size.
120 //
121 // A hashmap provides functions for adding, removing, and finding
122 // entries. It also provides a function to iterate over all entries
123 // in the hashmap.
124
125 class JvmtiTagHashmap : public CHeapObj<mtInternal> {
126 private:
127 friend class JvmtiTagMap;
128
129 enum {
130 small_trace_threshold = 10000, // threshold for tracing
131 medium_trace_threshold = 100000,
132 large_trace_threshold = 1000000,
133 initial_trace_threshold = small_trace_threshold
134 };
135
136 static int _sizes[]; // array of possible hashmap sizes
137 int _size; // actual size of the table
138 int _size_index; // index into size table
139
140 int _entry_count; // number of entries in the hashmap
141
142 float _load_factor; // load factor as a % of the size
143 int _resize_threshold; // computed threshold to trigger resizing.
144 bool _resizing_enabled; // indicates if hashmap can resize
145
146 int _trace_threshold; // threshold for trace messages
147
148 JvmtiTagHashmapEntry** _table; // the table of entries.
149
150 // private accessors
151 int resize_threshold() const { return _resize_threshold; }
152 int trace_threshold() const { return _trace_threshold; }
153
154 // initialize the hashmap
155 void init(int size_index=0, float load_factor=4.0f) {
156 int initial_size = _sizes[size_index];
157 _size_index = size_index;
158 _size = initial_size;
159 _entry_count = 0;
160 _trace_threshold = initial_trace_threshold;
161 _load_factor = load_factor;
162 _resize_threshold = (int)(_load_factor * _size);
163 _resizing_enabled = true;
164 size_t s = initial_size * sizeof(JvmtiTagHashmapEntry*);
165 _table = (JvmtiTagHashmapEntry**)os::malloc(s, mtInternal);
166 if (_table == NULL) {
167 vm_exit_out_of_memory(s, OOM_MALLOC_ERROR,
168 "unable to allocate initial hashtable for jvmti object tags");
169 }
170 for (int i=0; i<initial_size; i++) {
171 _table[i] = NULL;
172 }
173 }
174
175 // hash a given key (oop) with the specified size
176 static unsigned int hash(oop key, int size) {
177 // shift right to get better distribution (as these bits will be zero
178 // with aligned addresses)
179 unsigned int addr = (unsigned int)(cast_from_oop<intptr_t>(key));
180 #ifdef _LP64
181 return (addr >> 3) % size;
182 #else
183 return (addr >> 2) % size;
184 #endif
185 }
186
187 // hash a given key (oop)
188 unsigned int hash(oop key) {
189 return hash(key, _size);
190 }
191
192 // resize the hashmap - allocates a large table and re-hashes
193 // all entries into the new table.
194 void resize() {
195 int new_size_index = _size_index+1;
196 int new_size = _sizes[new_size_index];
197 if (new_size < 0) {
198 // hashmap already at maximum capacity
199 return;
200 }
201
202 // allocate new table
203 size_t s = new_size * sizeof(JvmtiTagHashmapEntry*);
204 JvmtiTagHashmapEntry** new_table = (JvmtiTagHashmapEntry**)os::malloc(s, mtInternal);
205 if (new_table == NULL) {
206 warning("unable to allocate larger hashtable for jvmti object tags");
207 set_resizing_enabled(false);
208 return;
209 }
210
211 // initialize new table
212 int i;
213 for (i=0; i<new_size; i++) {
214 new_table[i] = NULL;
215 }
216
217 // rehash all entries into the new table
218 for (i=0; i<_size; i++) {
219 JvmtiTagHashmapEntry* entry = _table[i];
220 while (entry != NULL) {
221 JvmtiTagHashmapEntry* next = entry->next();
222 oop key = entry->object_peek();
223 assert(key != NULL, "jni weak reference cleared!!");
224 unsigned int h = hash(key, new_size);
225 JvmtiTagHashmapEntry* anchor = new_table[h];
226 if (anchor == NULL) {
227 new_table[h] = entry;
228 entry->set_next(NULL);
229 } else {
230 entry->set_next(anchor);
231 new_table[h] = entry;
232 }
233 entry = next;
234 }
235 }
236
237 // free old table and update settings.
238 os::free((void*)_table);
239 _table = new_table;
240 _size_index = new_size_index;
241 _size = new_size;
242
243 // compute new resize threshold
244 _resize_threshold = (int)(_load_factor * _size);
245 }
246
247
248 // internal remove function - remove an entry at a given position in the
249 // table.
250 inline void remove(JvmtiTagHashmapEntry* prev, int pos, JvmtiTagHashmapEntry* entry) {
251 assert(pos >= 0 && pos < _size, "out of range");
252 if (prev == NULL) {
253 _table[pos] = entry->next();
254 } else {
255 prev->set_next(entry->next());
256 }
257 assert(_entry_count > 0, "checking");
258 _entry_count--;
259 }
260
261 // resizing switch
262 bool is_resizing_enabled() const { return _resizing_enabled; }
263 void set_resizing_enabled(bool enable) { _resizing_enabled = enable; }
264
265 // debugging
266 void print_memory_usage();
267 void compute_next_trace_threshold();
268
269 public:
270
271 // create a JvmtiTagHashmap of a preferred size and optionally a load factor.
272 // The preferred size is rounded down to an actual size.
273 JvmtiTagHashmap(int size, float load_factor=0.0f) {
274 int i=0;
275 while (_sizes[i] < size) {
276 if (_sizes[i] < 0) {
277 assert(i > 0, "sanity check");
278 i--;
279 break;
280 }
281 i++;
282 }
283
284 // if a load factor is specified then use it, otherwise use default
285 if (load_factor > 0.01f) {
286 init(i, load_factor);
287 } else {
288 init(i);
289 }
290 }
291
292 // create a JvmtiTagHashmap with default settings
293 JvmtiTagHashmap() {
294 init();
295 }
296
297 // release table when JvmtiTagHashmap destroyed
298 ~JvmtiTagHashmap() {
299 if (_table != NULL) {
300 os::free((void*)_table);
301 _table = NULL;
302 }
303 }
304
305 // accessors
306 int size() const { return _size; }
307 JvmtiTagHashmapEntry** table() const { return _table; }
308 int entry_count() const { return _entry_count; }
309
310 // find an entry in the hashmap, returns NULL if not found.
311 inline JvmtiTagHashmapEntry* find(oop key) {
312 unsigned int h = hash(key);
313 JvmtiTagHashmapEntry* entry = _table[h];
314 while (entry != NULL) {
315 if (entry->equals(key)) {
316 return entry;
317 }
318 entry = entry->next();
319 }
320 return NULL;
321 }
322
323
324 // add a new entry to hashmap
325 inline void add(oop key, JvmtiTagHashmapEntry* entry) {
326 assert(key != NULL, "checking");
327 assert(find(key) == NULL, "duplicate detected");
328 unsigned int h = hash(key);
329 JvmtiTagHashmapEntry* anchor = _table[h];
330 if (anchor == NULL) {
331 _table[h] = entry;
332 entry->set_next(NULL);
333 } else {
334 entry->set_next(anchor);
335 _table[h] = entry;
336 }
337
338 _entry_count++;
339 if (log_is_enabled(Debug, jvmti, objecttagging) && entry_count() >= trace_threshold()) {
340 print_memory_usage();
341 compute_next_trace_threshold();
342 }
343
344 // if the number of entries exceed the threshold then resize
345 if (entry_count() > resize_threshold() && is_resizing_enabled()) {
346 resize();
347 }
348 }
349
350 // remove an entry with the given key.
351 inline JvmtiTagHashmapEntry* remove(oop key) {
352 unsigned int h = hash(key);
353 JvmtiTagHashmapEntry* entry = _table[h];
354 JvmtiTagHashmapEntry* prev = NULL;
355 while (entry != NULL) {
356 if (entry->equals(key)) {
357 break;
358 }
359 prev = entry;
360 entry = entry->next();
361 }
362 if (entry != NULL) {
363 remove(prev, h, entry);
364 }
365 return entry;
366 }
367
368 // iterate over all entries in the hashmap
369 void entry_iterate(JvmtiTagHashmapEntryClosure* closure);
370 };
371
372 // possible hashmap sizes - odd primes that roughly double in size.
373 // To avoid excessive resizing the odd primes from 4801-76831 and
374 // 76831-307261 have been removed. The list must be terminated by -1.
375 int JvmtiTagHashmap::_sizes[] = { 4801, 76831, 307261, 614563, 1228891,
376 2457733, 4915219, 9830479, 19660831, 39321619, 78643219, -1 };
377
378
379 // A supporting class for iterating over all entries in Hashmap
380 class JvmtiTagHashmapEntryClosure {
381 public:
382 virtual void do_entry(JvmtiTagHashmapEntry* entry) = 0;
383 };
384
385
386 // iterate over all entries in the hashmap
387 void JvmtiTagHashmap::entry_iterate(JvmtiTagHashmapEntryClosure* closure) {
388 for (int i=0; i<_size; i++) {
389 JvmtiTagHashmapEntry* entry = _table[i];
390 JvmtiTagHashmapEntry* prev = NULL;
391 while (entry != NULL) {
392 // obtain the next entry before invoking do_entry - this is
393 // necessary because do_entry may remove the entry from the
394 // hashmap.
395 JvmtiTagHashmapEntry* next = entry->next();
396 closure->do_entry(entry);
397 entry = next;
398 }
399 }
400 }
401
402 // debugging
403 void JvmtiTagHashmap::print_memory_usage() {
404 intptr_t p = (intptr_t)this;
405 tty->print("[JvmtiTagHashmap @ " INTPTR_FORMAT, p);
406
407 // table + entries in KB
408 int hashmap_usage = (size()*sizeof(JvmtiTagHashmapEntry*) +
409 entry_count()*sizeof(JvmtiTagHashmapEntry))/K;
410
411 int weak_globals_usage = (int)(JNIHandles::weak_global_handle_memory_usage()/K);
412 tty->print_cr(", %d entries (%d KB) <JNI weak globals: %d KB>]",
413 entry_count(), hashmap_usage, weak_globals_usage);
414 }
415
416 // compute threshold for the next trace message
417 void JvmtiTagHashmap::compute_next_trace_threshold() {
418 _trace_threshold = entry_count();
419 if (trace_threshold() < medium_trace_threshold) {
420 _trace_threshold += small_trace_threshold;
421 } else {
422 if (trace_threshold() < large_trace_threshold) {
423 _trace_threshold += medium_trace_threshold;
424 } else {
425 _trace_threshold += large_trace_threshold;
426 }
427 }
428 }
429
430 // create a JvmtiTagMap
431 JvmtiTagMap::JvmtiTagMap(JvmtiEnv* env) :
432 _env(env),
433 _lock(Mutex::nonleaf+2, "JvmtiTagMap._lock", false),
434 _free_entries(NULL),
435 _free_entries_count(0)
436 {
437 assert(JvmtiThreadState_lock->is_locked(), "sanity check");
438 assert(((JvmtiEnvBase *)env)->tag_map() == NULL, "tag map already exists for environment");
439
440 _hashmap = new JvmtiTagHashmap();
441
442 // finally add us to the environment
443 ((JvmtiEnvBase *)env)->set_tag_map(this);
444 }
445
446
447 // destroy a JvmtiTagMap
448 JvmtiTagMap::~JvmtiTagMap() {
449
450 // no lock acquired as we assume the enclosing environment is
451 // also being destroryed.
452 ((JvmtiEnvBase *)_env)->set_tag_map(NULL);
453
454 JvmtiTagHashmapEntry** table = _hashmap->table();
455 for (int j = 0; j < _hashmap->size(); j++) {
456 JvmtiTagHashmapEntry* entry = table[j];
457 while (entry != NULL) {
458 JvmtiTagHashmapEntry* next = entry->next();
459 delete entry;
460 entry = next;
461 }
462 }
463
464 // finally destroy the hashmap
465 delete _hashmap;
466 _hashmap = NULL;
467
468 // remove any entries on the free list
469 JvmtiTagHashmapEntry* entry = _free_entries;
470 while (entry != NULL) {
471 JvmtiTagHashmapEntry* next = entry->next();
472 delete entry;
473 entry = next;
474 }
475 _free_entries = NULL;
476 }
477
478 // create a hashmap entry
479 // - if there's an entry on the (per-environment) free list then this
480 // is returned. Otherwise an new entry is allocated.
481 JvmtiTagHashmapEntry* JvmtiTagMap::create_entry(oop ref, jlong tag) {
482 assert(Thread::current()->is_VM_thread() || is_locked(), "checking");
483 JvmtiTagHashmapEntry* entry;
484 if (_free_entries == NULL) {
485 entry = new JvmtiTagHashmapEntry(ref, tag);
486 } else {
487 assert(_free_entries_count > 0, "mismatched _free_entries_count");
488 _free_entries_count--;
489 entry = _free_entries;
490 _free_entries = entry->next();
491 entry->init(ref, tag);
492 }
493 return entry;
494 }
495
496 // destroy an entry by returning it to the free list
497 void JvmtiTagMap::destroy_entry(JvmtiTagHashmapEntry* entry) {
498 assert(SafepointSynchronize::is_at_safepoint() || is_locked(), "checking");
499 // limit the size of the free list
500 if (_free_entries_count >= max_free_entries) {
501 delete entry;
502 } else {
503 entry->set_next(_free_entries);
504 _free_entries = entry;
505 _free_entries_count++;
506 }
507 }
508
509 // returns the tag map for the given environments. If the tag map
510 // doesn't exist then it is created.
511 JvmtiTagMap* JvmtiTagMap::tag_map_for(JvmtiEnv* env) {
512 JvmtiTagMap* tag_map = ((JvmtiEnvBase*)env)->tag_map();
513 if (tag_map == NULL) {
514 MutexLocker mu(JvmtiThreadState_lock);
515 tag_map = ((JvmtiEnvBase*)env)->tag_map();
516 if (tag_map == NULL) {
517 tag_map = new JvmtiTagMap(env);
518 }
519 } else {
520 CHECK_UNHANDLED_OOPS_ONLY(Thread::current()->clear_unhandled_oops());
521 }
522 return tag_map;
523 }
524
525 // iterate over all entries in the tag map.
526 void JvmtiTagMap::entry_iterate(JvmtiTagHashmapEntryClosure* closure) {
527 hashmap()->entry_iterate(closure);
528 }
529
530 // returns true if the hashmaps are empty
531 bool JvmtiTagMap::is_empty() {
532 assert(SafepointSynchronize::is_at_safepoint() || is_locked(), "checking");
533 return hashmap()->entry_count() == 0;
534 }
535
536
537 // Return the tag value for an object, or 0 if the object is
538 // not tagged
539 //
540 static inline jlong tag_for(JvmtiTagMap* tag_map, oop o) {
541 JvmtiTagHashmapEntry* entry = tag_map->hashmap()->find(o);
542 if (entry == NULL) {
543 return 0;
544 } else {
545 return entry->tag();
546 }
547 }
548
549
550 // A CallbackWrapper is a support class for querying and tagging an object
551 // around a callback to a profiler. The constructor does pre-callback
552 // work to get the tag value, klass tag value, ... and the destructor
553 // does the post-callback work of tagging or untagging the object.
554 //
555 // {
556 // CallbackWrapper wrapper(tag_map, o);
557 //
558 // (*callback)(wrapper.klass_tag(), wrapper.obj_size(), wrapper.obj_tag_p(), ...)
559 //
560 // } // wrapper goes out of scope here which results in the destructor
561 // checking to see if the object has been tagged, untagged, or the
562 // tag value has changed.
563 //
564 class CallbackWrapper : public StackObj {
565 private:
566 JvmtiTagMap* _tag_map;
567 JvmtiTagHashmap* _hashmap;
568 JvmtiTagHashmapEntry* _entry;
569 oop _o;
570 jlong _obj_size;
571 jlong _obj_tag;
572 jlong _klass_tag;
573
574 protected:
575 JvmtiTagMap* tag_map() const { return _tag_map; }
576
577 // invoked post-callback to tag, untag, or update the tag of an object
578 void inline post_callback_tag_update(oop o, JvmtiTagHashmap* hashmap,
579 JvmtiTagHashmapEntry* entry, jlong obj_tag);
580 public:
581 CallbackWrapper(JvmtiTagMap* tag_map, oop o) {
582 assert(Thread::current()->is_VM_thread() || tag_map->is_locked(),
583 "MT unsafe or must be VM thread");
584
585 // object to tag
586 _o = o;
587
588 // object size
589 _obj_size = (jlong)_o->size() * wordSize;
590
591 // record the context
592 _tag_map = tag_map;
593 _hashmap = tag_map->hashmap();
594 _entry = _hashmap->find(_o);
595
596 // get object tag
597 _obj_tag = (_entry == NULL) ? 0 : _entry->tag();
598
599 // get the class and the class's tag value
600 assert(SystemDictionary::Class_klass()->is_mirror_instance_klass(), "Is not?");
601
602 _klass_tag = tag_for(tag_map, _o->klass()->java_mirror());
603 }
604
605 ~CallbackWrapper() {
606 post_callback_tag_update(_o, _hashmap, _entry, _obj_tag);
607 }
608
609 inline jlong* obj_tag_p() { return &_obj_tag; }
610 inline jlong obj_size() const { return _obj_size; }
611 inline jlong obj_tag() const { return _obj_tag; }
612 inline jlong klass_tag() const { return _klass_tag; }
613 };
614
615
616
617 // callback post-callback to tag, untag, or update the tag of an object
618 void inline CallbackWrapper::post_callback_tag_update(oop o,
619 JvmtiTagHashmap* hashmap,
620 JvmtiTagHashmapEntry* entry,
621 jlong obj_tag) {
622 if (entry == NULL) {
623 if (obj_tag != 0) {
624 // callback has tagged the object
625 assert(Thread::current()->is_VM_thread(), "must be VMThread");
626 entry = tag_map()->create_entry(o, obj_tag);
627 hashmap->add(o, entry);
628 }
629 } else {
630 // object was previously tagged - the callback may have untagged
631 // the object or changed the tag value
632 if (obj_tag == 0) {
633
634 JvmtiTagHashmapEntry* entry_removed = hashmap->remove(o);
635 assert(entry_removed == entry, "checking");
636 tag_map()->destroy_entry(entry);
637
638 } else {
639 if (obj_tag != entry->tag()) {
640 entry->set_tag(obj_tag);
641 }
642 }
643 }
644 }
645
646 // An extended CallbackWrapper used when reporting an object reference
647 // to the agent.
648 //
649 // {
650 // TwoOopCallbackWrapper wrapper(tag_map, referrer, o);
651 //
652 // (*callback)(wrapper.klass_tag(),
653 // wrapper.obj_size(),
654 // wrapper.obj_tag_p()
655 // wrapper.referrer_tag_p(), ...)
656 //
657 // } // wrapper goes out of scope here which results in the destructor
658 // checking to see if the referrer object has been tagged, untagged,
659 // or the tag value has changed.
660 //
661 class TwoOopCallbackWrapper : public CallbackWrapper {
662 private:
663 bool _is_reference_to_self;
664 JvmtiTagHashmap* _referrer_hashmap;
665 JvmtiTagHashmapEntry* _referrer_entry;
666 oop _referrer;
667 jlong _referrer_obj_tag;
668 jlong _referrer_klass_tag;
669 jlong* _referrer_tag_p;
670
671 bool is_reference_to_self() const { return _is_reference_to_self; }
672
673 public:
674 TwoOopCallbackWrapper(JvmtiTagMap* tag_map, oop referrer, oop o) :
675 CallbackWrapper(tag_map, o)
676 {
677 // self reference needs to be handled in a special way
678 _is_reference_to_self = (referrer == o);
679
680 if (_is_reference_to_self) {
681 _referrer_klass_tag = klass_tag();
682 _referrer_tag_p = obj_tag_p();
683 } else {
684 _referrer = referrer;
685 // record the context
686 _referrer_hashmap = tag_map->hashmap();
687 _referrer_entry = _referrer_hashmap->find(_referrer);
688
689 // get object tag
690 _referrer_obj_tag = (_referrer_entry == NULL) ? 0 : _referrer_entry->tag();
691 _referrer_tag_p = &_referrer_obj_tag;
692
693 // get referrer class tag.
694 _referrer_klass_tag = tag_for(tag_map, _referrer->klass()->java_mirror());
695 }
696 }
697
698 ~TwoOopCallbackWrapper() {
699 if (!is_reference_to_self()){
700 post_callback_tag_update(_referrer,
701 _referrer_hashmap,
702 _referrer_entry,
703 _referrer_obj_tag);
704 }
705 }
706
707 // address of referrer tag
708 // (for a self reference this will return the same thing as obj_tag_p())
709 inline jlong* referrer_tag_p() { return _referrer_tag_p; }
710
711 // referrer's class tag
712 inline jlong referrer_klass_tag() { return _referrer_klass_tag; }
713 };
714
715 // tag an object
716 //
717 // This function is performance critical. If many threads attempt to tag objects
718 // around the same time then it's possible that the Mutex associated with the
719 // tag map will be a hot lock.
720 void JvmtiTagMap::set_tag(jobject object, jlong tag) {
721 MutexLocker ml(lock());
722
723 // resolve the object
724 oop o = JNIHandles::resolve_non_null(object);
725
726 // see if the object is already tagged
727 JvmtiTagHashmap* hashmap = _hashmap;
728 JvmtiTagHashmapEntry* entry = hashmap->find(o);
729
730 // if the object is not already tagged then we tag it
731 if (entry == NULL) {
732 if (tag != 0) {
733 entry = create_entry(o, tag);
734 hashmap->add(o, entry);
735 } else {
736 // no-op
737 }
738 } else {
739 // if the object is already tagged then we either update
740 // the tag (if a new tag value has been provided)
741 // or remove the object if the new tag value is 0.
742 if (tag == 0) {
743 hashmap->remove(o);
744 destroy_entry(entry);
745 } else {
746 entry->set_tag(tag);
747 }
748 }
749 }
750
751 // get the tag for an object
752 jlong JvmtiTagMap::get_tag(jobject object) {
753 MutexLocker ml(lock());
754
755 // resolve the object
756 oop o = JNIHandles::resolve_non_null(object);
757
758 return tag_for(this, o);
759 }
760
761
762 // Helper class used to describe the static or instance fields of a class.
763 // For each field it holds the field index (as defined by the JVMTI specification),
764 // the field type, and the offset.
765
766 class ClassFieldDescriptor: public CHeapObj<mtInternal> {
767 private:
768 int _field_index;
769 int _field_offset;
770 char _field_type;
771 public:
772 ClassFieldDescriptor(int index, char type, int offset) :
773 _field_index(index), _field_type(type), _field_offset(offset) {
774 }
775 int field_index() const { return _field_index; }
776 char field_type() const { return _field_type; }
777 int field_offset() const { return _field_offset; }
778 };
779
780 class ClassFieldMap: public CHeapObj<mtInternal> {
781 private:
782 enum {
783 initial_field_count = 5
784 };
785
786 // list of field descriptors
787 GrowableArray<ClassFieldDescriptor*>* _fields;
788
789 // constructor
790 ClassFieldMap();
791
792 // add a field
793 void add(int index, char type, int offset);
794
795 // returns the field count for the given class
796 static int compute_field_count(InstanceKlass* ik);
797
798 public:
799 ~ClassFieldMap();
800
801 // access
802 int field_count() { return _fields->length(); }
803 ClassFieldDescriptor* field_at(int i) { return _fields->at(i); }
804
805 // functions to create maps of static or instance fields
806 static ClassFieldMap* create_map_of_static_fields(Klass* k);
807 static ClassFieldMap* create_map_of_instance_fields(oop obj);
808 };
809
810 ClassFieldMap::ClassFieldMap() {
811 _fields = new (ResourceObj::C_HEAP, mtInternal)
812 GrowableArray<ClassFieldDescriptor*>(initial_field_count, true);
813 }
814
815 ClassFieldMap::~ClassFieldMap() {
816 for (int i=0; i<_fields->length(); i++) {
817 delete _fields->at(i);
818 }
819 delete _fields;
820 }
821
822 void ClassFieldMap::add(int index, char type, int offset) {
823 ClassFieldDescriptor* field = new ClassFieldDescriptor(index, type, offset);
824 _fields->append(field);
825 }
826
827 // Returns a heap allocated ClassFieldMap to describe the static fields
828 // of the given class.
829 //
830 ClassFieldMap* ClassFieldMap::create_map_of_static_fields(Klass* k) {
831 HandleMark hm;
832 InstanceKlass* ik = InstanceKlass::cast(k);
833
834 // create the field map
835 ClassFieldMap* field_map = new ClassFieldMap();
836
837 FilteredFieldStream f(ik, false, false);
838 int max_field_index = f.field_count()-1;
839
840 int index = 0;
841 for (FilteredFieldStream fld(ik, true, true); !fld.eos(); fld.next(), index++) {
842 // ignore instance fields
843 if (!fld.access_flags().is_static()) {
844 continue;
845 }
846 field_map->add(max_field_index - index, fld.signature()->byte_at(0), fld.offset());
847 }
848 return field_map;
849 }
850
851 // Returns a heap allocated ClassFieldMap to describe the instance fields
852 // of the given class. All instance fields are included (this means public
853 // and private fields declared in superclasses and superinterfaces too).
854 //
855 ClassFieldMap* ClassFieldMap::create_map_of_instance_fields(oop obj) {
856 HandleMark hm;
857 InstanceKlass* ik = InstanceKlass::cast(obj->klass());
858
859 // create the field map
860 ClassFieldMap* field_map = new ClassFieldMap();
861
862 FilteredFieldStream f(ik, false, false);
863
864 int max_field_index = f.field_count()-1;
865
866 int index = 0;
867 for (FilteredFieldStream fld(ik, false, false); !fld.eos(); fld.next(), index++) {
868 // ignore static fields
869 if (fld.access_flags().is_static()) {
870 continue;
871 }
872 field_map->add(max_field_index - index, fld.signature()->byte_at(0), fld.offset());
873 }
874
875 return field_map;
876 }
877
878 // Helper class used to cache a ClassFileMap for the instance fields of
879 // a cache. A JvmtiCachedClassFieldMap can be cached by an InstanceKlass during
880 // heap iteration and avoid creating a field map for each object in the heap
881 // (only need to create the map when the first instance of a class is encountered).
882 //
883 class JvmtiCachedClassFieldMap : public CHeapObj<mtInternal> {
884 private:
885 enum {
886 initial_class_count = 200
887 };
888 ClassFieldMap* _field_map;
889
890 ClassFieldMap* field_map() const { return _field_map; }
891
892 JvmtiCachedClassFieldMap(ClassFieldMap* field_map);
893 ~JvmtiCachedClassFieldMap();
894
895 static GrowableArray<InstanceKlass*>* _class_list;
896 static void add_to_class_list(InstanceKlass* ik);
897
898 public:
899 // returns the field map for a given object (returning map cached
900 // by InstanceKlass if possible
901 static ClassFieldMap* get_map_of_instance_fields(oop obj);
902
903 // removes the field map from all instanceKlasses - should be
904 // called before VM operation completes
905 static void clear_cache();
906
907 // returns the number of ClassFieldMap cached by instanceKlasses
908 static int cached_field_map_count();
909 };
910
911 GrowableArray<InstanceKlass*>* JvmtiCachedClassFieldMap::_class_list;
912
913 JvmtiCachedClassFieldMap::JvmtiCachedClassFieldMap(ClassFieldMap* field_map) {
914 _field_map = field_map;
915 }
916
917 JvmtiCachedClassFieldMap::~JvmtiCachedClassFieldMap() {
918 if (_field_map != NULL) {
919 delete _field_map;
920 }
921 }
922
923 // Marker class to ensure that the class file map cache is only used in a defined
924 // scope.
925 class ClassFieldMapCacheMark : public StackObj {
926 private:
927 static bool _is_active;
928 public:
929 ClassFieldMapCacheMark() {
930 assert(Thread::current()->is_VM_thread(), "must be VMThread");
931 assert(JvmtiCachedClassFieldMap::cached_field_map_count() == 0, "cache not empty");
932 assert(!_is_active, "ClassFieldMapCacheMark cannot be nested");
933 _is_active = true;
934 }
935 ~ClassFieldMapCacheMark() {
936 JvmtiCachedClassFieldMap::clear_cache();
937 _is_active = false;
938 }
939 static bool is_active() { return _is_active; }
940 };
941
942 bool ClassFieldMapCacheMark::_is_active;
943
944
945 // record that the given InstanceKlass is caching a field map
946 void JvmtiCachedClassFieldMap::add_to_class_list(InstanceKlass* ik) {
947 if (_class_list == NULL) {
948 _class_list = new (ResourceObj::C_HEAP, mtInternal)
949 GrowableArray<InstanceKlass*>(initial_class_count, true);
950 }
951 _class_list->push(ik);
952 }
953
954 // returns the instance field map for the given object
955 // (returns field map cached by the InstanceKlass if possible)
956 ClassFieldMap* JvmtiCachedClassFieldMap::get_map_of_instance_fields(oop obj) {
957 assert(Thread::current()->is_VM_thread(), "must be VMThread");
958 assert(ClassFieldMapCacheMark::is_active(), "ClassFieldMapCacheMark not active");
959
960 Klass* k = obj->klass();
961 InstanceKlass* ik = InstanceKlass::cast(k);
962
963 // return cached map if possible
964 JvmtiCachedClassFieldMap* cached_map = ik->jvmti_cached_class_field_map();
965 if (cached_map != NULL) {
966 assert(cached_map->field_map() != NULL, "missing field list");
967 return cached_map->field_map();
968 } else {
969 ClassFieldMap* field_map = ClassFieldMap::create_map_of_instance_fields(obj);
970 cached_map = new JvmtiCachedClassFieldMap(field_map);
971 ik->set_jvmti_cached_class_field_map(cached_map);
972 add_to_class_list(ik);
973 return field_map;
974 }
975 }
976
977 // remove the fields maps cached from all instanceKlasses
978 void JvmtiCachedClassFieldMap::clear_cache() {
979 assert(Thread::current()->is_VM_thread(), "must be VMThread");
980 if (_class_list != NULL) {
981 for (int i = 0; i < _class_list->length(); i++) {
982 InstanceKlass* ik = _class_list->at(i);
983 JvmtiCachedClassFieldMap* cached_map = ik->jvmti_cached_class_field_map();
984 assert(cached_map != NULL, "should not be NULL");
985 ik->set_jvmti_cached_class_field_map(NULL);
986 delete cached_map; // deletes the encapsulated field map
987 }
988 delete _class_list;
989 _class_list = NULL;
990 }
991 }
992
993 // returns the number of ClassFieldMap cached by instanceKlasses
994 int JvmtiCachedClassFieldMap::cached_field_map_count() {
995 return (_class_list == NULL) ? 0 : _class_list->length();
996 }
997
998 // helper function to indicate if an object is filtered by its tag or class tag
999 static inline bool is_filtered_by_heap_filter(jlong obj_tag,
1000 jlong klass_tag,
1001 int heap_filter) {
1002 // apply the heap filter
1003 if (obj_tag != 0) {
1004 // filter out tagged objects
1005 if (heap_filter & JVMTI_HEAP_FILTER_TAGGED) return true;
1006 } else {
1007 // filter out untagged objects
1008 if (heap_filter & JVMTI_HEAP_FILTER_UNTAGGED) return true;
1009 }
1010 if (klass_tag != 0) {
1011 // filter out objects with tagged classes
1012 if (heap_filter & JVMTI_HEAP_FILTER_CLASS_TAGGED) return true;
1013 } else {
1014 // filter out objects with untagged classes.
1015 if (heap_filter & JVMTI_HEAP_FILTER_CLASS_UNTAGGED) return true;
1016 }
1017 return false;
1018 }
1019
1020 // helper function to indicate if an object is filtered by a klass filter
1021 static inline bool is_filtered_by_klass_filter(oop obj, Klass* klass_filter) {
1022 if (klass_filter != NULL) {
1023 if (obj->klass() != klass_filter) {
1024 return true;
1025 }
1026 }
1027 return false;
1028 }
1029
1030 // helper function to tell if a field is a primitive field or not
1031 static inline bool is_primitive_field_type(char type) {
1032 return (type != 'L' && type != '[');
1033 }
1034
1035 // helper function to copy the value from location addr to jvalue.
1036 static inline void copy_to_jvalue(jvalue *v, address addr, jvmtiPrimitiveType value_type) {
1037 switch (value_type) {
1038 case JVMTI_PRIMITIVE_TYPE_BOOLEAN : { v->z = *(jboolean*)addr; break; }
1039 case JVMTI_PRIMITIVE_TYPE_BYTE : { v->b = *(jbyte*)addr; break; }
1040 case JVMTI_PRIMITIVE_TYPE_CHAR : { v->c = *(jchar*)addr; break; }
1041 case JVMTI_PRIMITIVE_TYPE_SHORT : { v->s = *(jshort*)addr; break; }
1042 case JVMTI_PRIMITIVE_TYPE_INT : { v->i = *(jint*)addr; break; }
1043 case JVMTI_PRIMITIVE_TYPE_LONG : { v->j = *(jlong*)addr; break; }
1044 case JVMTI_PRIMITIVE_TYPE_FLOAT : { v->f = *(jfloat*)addr; break; }
1045 case JVMTI_PRIMITIVE_TYPE_DOUBLE : { v->d = *(jdouble*)addr; break; }
1046 default: ShouldNotReachHere();
1047 }
1048 }
1049
1050 // helper function to invoke string primitive value callback
1051 // returns visit control flags
1052 static jint invoke_string_value_callback(jvmtiStringPrimitiveValueCallback cb,
1053 CallbackWrapper* wrapper,
1054 oop str,
1055 void* user_data)
1056 {
1057 assert(str->klass() == SystemDictionary::String_klass(), "not a string");
1058
1059 typeArrayOop s_value = java_lang_String::value(str);
1060
1061 // JDK-6584008: the value field may be null if a String instance is
1062 // partially constructed.
1063 if (s_value == NULL) {
1064 return 0;
1065 }
1066 // get the string value and length
1067 // (string value may be offset from the base)
1068 int s_len = java_lang_String::length(str);
1069 bool is_latin1 = java_lang_String::is_latin1(str);
1070 jchar* value;
1071 if (s_len > 0) {
1072 if (!is_latin1) {
1073 value = s_value->char_at_addr(0);
1074 } else {
1075 // Inflate latin1 encoded string to UTF16
1076 jchar* buf = NEW_C_HEAP_ARRAY(jchar, s_len, mtInternal);
1077 for (int i = 0; i < s_len; i++) {
1078 buf[i] = ((jchar) s_value->byte_at(i)) & 0xff;
1079 }
1080 value = &buf[0];
1081 }
1082 } else {
1083 // Don't use char_at_addr(0) if length is 0
1084 value = (jchar*) s_value->base(T_CHAR);
1085 }
1086
1087 // invoke the callback
1088 jint res = (*cb)(wrapper->klass_tag(),
1089 wrapper->obj_size(),
1090 wrapper->obj_tag_p(),
1091 value,
1092 (jint)s_len,
1093 user_data);
1094
1095 if (is_latin1 && s_len > 0) {
1096 FREE_C_HEAP_ARRAY(jchar, value);
1097 }
1098 return res;
1099 }
1100
1101 // helper function to invoke string primitive value callback
1102 // returns visit control flags
1103 static jint invoke_array_primitive_value_callback(jvmtiArrayPrimitiveValueCallback cb,
1104 CallbackWrapper* wrapper,
1105 oop obj,
1106 void* user_data)
1107 {
1108 assert(obj->is_typeArray(), "not a primitive array");
1109
1110 // get base address of first element
1111 typeArrayOop array = typeArrayOop(obj);
1112 BasicType type = TypeArrayKlass::cast(array->klass())->element_type();
1113 void* elements = array->base(type);
1114
1115 // jvmtiPrimitiveType is defined so this mapping is always correct
1116 jvmtiPrimitiveType elem_type = (jvmtiPrimitiveType)type2char(type);
1117
1118 return (*cb)(wrapper->klass_tag(),
1119 wrapper->obj_size(),
1120 wrapper->obj_tag_p(),
1121 (jint)array->length(),
1122 elem_type,
1123 elements,
1124 user_data);
1125 }
1126
1127 // helper function to invoke the primitive field callback for all static fields
1128 // of a given class
1129 static jint invoke_primitive_field_callback_for_static_fields
1130 (CallbackWrapper* wrapper,
1131 oop obj,
1132 jvmtiPrimitiveFieldCallback cb,
1133 void* user_data)
1134 {
1135 // for static fields only the index will be set
1136 static jvmtiHeapReferenceInfo reference_info = { 0 };
1137
1138 assert(obj->klass() == SystemDictionary::Class_klass(), "not a class");
1139 if (java_lang_Class::is_primitive(obj)) {
1140 return 0;
1141 }
1142 Klass* klass = java_lang_Class::as_Klass(obj);
1143
1144 // ignore classes for object and type arrays
1145 if (!klass->is_instance_klass()) {
1146 return 0;
1147 }
1148
1149 // ignore classes which aren't linked yet
1150 InstanceKlass* ik = InstanceKlass::cast(klass);
1151 if (!ik->is_linked()) {
1152 return 0;
1153 }
1154
1155 // get the field map
1156 ClassFieldMap* field_map = ClassFieldMap::create_map_of_static_fields(klass);
1157
1158 // invoke the callback for each static primitive field
1159 for (int i=0; i<field_map->field_count(); i++) {
1160 ClassFieldDescriptor* field = field_map->field_at(i);
1161
1162 // ignore non-primitive fields
1163 char type = field->field_type();
1164 if (!is_primitive_field_type(type)) {
1165 continue;
1166 }
1167 // one-to-one mapping
1168 jvmtiPrimitiveType value_type = (jvmtiPrimitiveType)type;
1169
1170 // get offset and field value
1171 int offset = field->field_offset();
1172 address addr = (address)klass->java_mirror() + offset;
1173 jvalue value;
1174 copy_to_jvalue(&value, addr, value_type);
1175
1176 // field index
1177 reference_info.field.index = field->field_index();
1178
1179 // invoke the callback
1180 jint res = (*cb)(JVMTI_HEAP_REFERENCE_STATIC_FIELD,
1181 &reference_info,
1182 wrapper->klass_tag(),
1183 wrapper->obj_tag_p(),
1184 value,
1185 value_type,
1186 user_data);
1187 if (res & JVMTI_VISIT_ABORT) {
1188 delete field_map;
1189 return res;
1190 }
1191 }
1192
1193 delete field_map;
1194 return 0;
1195 }
1196
1197 // helper function to invoke the primitive field callback for all instance fields
1198 // of a given object
1199 static jint invoke_primitive_field_callback_for_instance_fields(
1200 CallbackWrapper* wrapper,
1201 oop obj,
1202 jvmtiPrimitiveFieldCallback cb,
1203 void* user_data)
1204 {
1205 // for instance fields only the index will be set
1206 static jvmtiHeapReferenceInfo reference_info = { 0 };
1207
1208 // get the map of the instance fields
1209 ClassFieldMap* fields = JvmtiCachedClassFieldMap::get_map_of_instance_fields(obj);
1210
1211 // invoke the callback for each instance primitive field
1212 for (int i=0; i<fields->field_count(); i++) {
1213 ClassFieldDescriptor* field = fields->field_at(i);
1214
1215 // ignore non-primitive fields
1216 char type = field->field_type();
1217 if (!is_primitive_field_type(type)) {
1218 continue;
1219 }
1220 // one-to-one mapping
1221 jvmtiPrimitiveType value_type = (jvmtiPrimitiveType)type;
1222
1223 // get offset and field value
1224 int offset = field->field_offset();
1225 address addr = (address)obj + offset;
1226 jvalue value;
1227 copy_to_jvalue(&value, addr, value_type);
1228
1229 // field index
1230 reference_info.field.index = field->field_index();
1231
1232 // invoke the callback
1233 jint res = (*cb)(JVMTI_HEAP_REFERENCE_FIELD,
1234 &reference_info,
1235 wrapper->klass_tag(),
1236 wrapper->obj_tag_p(),
1237 value,
1238 value_type,
1239 user_data);
1240 if (res & JVMTI_VISIT_ABORT) {
1241 return res;
1242 }
1243 }
1244 return 0;
1245 }
1246
1247
1248 // VM operation to iterate over all objects in the heap (both reachable
1249 // and unreachable)
1250 class VM_HeapIterateOperation: public VM_Operation {
1251 private:
1252 ObjectClosure* _blk;
1253 public:
1254 VM_HeapIterateOperation(ObjectClosure* blk) { _blk = blk; }
1255
1256 VMOp_Type type() const { return VMOp_HeapIterateOperation; }
1257 void doit() {
1258 // allows class files maps to be cached during iteration
1259 ClassFieldMapCacheMark cm;
1260
1261 // make sure that heap is parsable (fills TLABs with filler objects)
1262 Universe::heap()->ensure_parsability(false); // no need to retire TLABs
1263
1264 // Verify heap before iteration - if the heap gets corrupted then
1265 // JVMTI's IterateOverHeap will crash.
1266 if (VerifyBeforeIteration) {
1267 Universe::verify();
1268 }
1269
1270 // do the iteration
1271 // If this operation encounters a bad object when using CMS,
1272 // consider using safe_object_iterate() which avoids perm gen
1273 // objects that may contain bad references.
1274 Universe::heap()->object_iterate(_blk);
1275 }
1276
1277 };
1278
1279
1280 // An ObjectClosure used to support the deprecated IterateOverHeap and
1281 // IterateOverInstancesOfClass functions
1282 class IterateOverHeapObjectClosure: public ObjectClosure {
1283 private:
1284 JvmtiTagMap* _tag_map;
1285 Klass* _klass;
1286 jvmtiHeapObjectFilter _object_filter;
1287 jvmtiHeapObjectCallback _heap_object_callback;
1288 const void* _user_data;
1289
1290 // accessors
1291 JvmtiTagMap* tag_map() const { return _tag_map; }
1292 jvmtiHeapObjectFilter object_filter() const { return _object_filter; }
1293 jvmtiHeapObjectCallback object_callback() const { return _heap_object_callback; }
1294 Klass* klass() const { return _klass; }
1295 const void* user_data() const { return _user_data; }
1296
1297 // indicates if iteration has been aborted
1298 bool _iteration_aborted;
1299 bool is_iteration_aborted() const { return _iteration_aborted; }
1300 void set_iteration_aborted(bool aborted) { _iteration_aborted = aborted; }
1301
1302 public:
1303 IterateOverHeapObjectClosure(JvmtiTagMap* tag_map,
1304 Klass* klass,
1305 jvmtiHeapObjectFilter object_filter,
1306 jvmtiHeapObjectCallback heap_object_callback,
1307 const void* user_data) :
1308 _tag_map(tag_map),
1309 _klass(klass),
1310 _object_filter(object_filter),
1311 _heap_object_callback(heap_object_callback),
1312 _user_data(user_data),
1313 _iteration_aborted(false)
1314 {
1315 }
1316
1317 void do_object(oop o);
1318 };
1319
1320 // invoked for each object in the heap
1321 void IterateOverHeapObjectClosure::do_object(oop o) {
1322 // check if iteration has been halted
1323 if (is_iteration_aborted()) return;
1324
1325 // ignore any objects that aren't visible to profiler
1326 if (!ServiceUtil::visible_oop(o)) return;
1327
1328 // instanceof check when filtering by klass
1329 if (klass() != NULL && !o->is_a(klass())) {
1330 return;
1331 }
1332 // prepare for the calllback
1333 CallbackWrapper wrapper(tag_map(), o);
1334
1335 // if the object is tagged and we're only interested in untagged objects
1336 // then don't invoke the callback. Similiarly, if the object is untagged
1337 // and we're only interested in tagged objects we skip the callback.
1338 if (wrapper.obj_tag() != 0) {
1339 if (object_filter() == JVMTI_HEAP_OBJECT_UNTAGGED) return;
1340 } else {
1341 if (object_filter() == JVMTI_HEAP_OBJECT_TAGGED) return;
1342 }
1343
1344 // invoke the agent's callback
1345 jvmtiIterationControl control = (*object_callback())(wrapper.klass_tag(),
1346 wrapper.obj_size(),
1347 wrapper.obj_tag_p(),
1348 (void*)user_data());
1349 if (control == JVMTI_ITERATION_ABORT) {
1350 set_iteration_aborted(true);
1351 }
1352 }
1353
1354 // An ObjectClosure used to support the IterateThroughHeap function
1355 class IterateThroughHeapObjectClosure: public ObjectClosure {
1356 private:
1357 JvmtiTagMap* _tag_map;
1358 Klass* _klass;
1359 int _heap_filter;
1360 const jvmtiHeapCallbacks* _callbacks;
1361 const void* _user_data;
1362
1363 // accessor functions
1364 JvmtiTagMap* tag_map() const { return _tag_map; }
1365 int heap_filter() const { return _heap_filter; }
1366 const jvmtiHeapCallbacks* callbacks() const { return _callbacks; }
1367 Klass* klass() const { return _klass; }
1368 const void* user_data() const { return _user_data; }
1369
1370 // indicates if the iteration has been aborted
1371 bool _iteration_aborted;
1372 bool is_iteration_aborted() const { return _iteration_aborted; }
1373
1374 // used to check the visit control flags. If the abort flag is set
1375 // then we set the iteration aborted flag so that the iteration completes
1376 // without processing any further objects
1377 bool check_flags_for_abort(jint flags) {
1378 bool is_abort = (flags & JVMTI_VISIT_ABORT) != 0;
1379 if (is_abort) {
1380 _iteration_aborted = true;
1381 }
1382 return is_abort;
1383 }
1384
1385 public:
1386 IterateThroughHeapObjectClosure(JvmtiTagMap* tag_map,
1387 Klass* klass,
1388 int heap_filter,
1389 const jvmtiHeapCallbacks* heap_callbacks,
1390 const void* user_data) :
1391 _tag_map(tag_map),
1392 _klass(klass),
1393 _heap_filter(heap_filter),
1394 _callbacks(heap_callbacks),
1395 _user_data(user_data),
1396 _iteration_aborted(false)
1397 {
1398 }
1399
1400 void do_object(oop o);
1401 };
1402
1403 // invoked for each object in the heap
1404 void IterateThroughHeapObjectClosure::do_object(oop obj) {
1405 // check if iteration has been halted
1406 if (is_iteration_aborted()) return;
1407
1408 // ignore any objects that aren't visible to profiler
1409 if (!ServiceUtil::visible_oop(obj)) return;
1410
1411 // apply class filter
1412 if (is_filtered_by_klass_filter(obj, klass())) return;
1413
1414 // prepare for callback
1415 CallbackWrapper wrapper(tag_map(), obj);
1416
1417 // check if filtered by the heap filter
1418 if (is_filtered_by_heap_filter(wrapper.obj_tag(), wrapper.klass_tag(), heap_filter())) {
1419 return;
1420 }
1421
1422 // for arrays we need the length, otherwise -1
1423 bool is_array = obj->is_array();
1424 int len = is_array ? arrayOop(obj)->length() : -1;
1425
1426 // invoke the object callback (if callback is provided)
1427 if (callbacks()->heap_iteration_callback != NULL) {
1428 jvmtiHeapIterationCallback cb = callbacks()->heap_iteration_callback;
1429 jint res = (*cb)(wrapper.klass_tag(),
1430 wrapper.obj_size(),
1431 wrapper.obj_tag_p(),
1432 (jint)len,
1433 (void*)user_data());
1434 if (check_flags_for_abort(res)) return;
1435 }
1436
1437 // for objects and classes we report primitive fields if callback provided
1438 if (callbacks()->primitive_field_callback != NULL && obj->is_instance()) {
1439 jint res;
1440 jvmtiPrimitiveFieldCallback cb = callbacks()->primitive_field_callback;
1441 if (obj->klass() == SystemDictionary::Class_klass()) {
1442 res = invoke_primitive_field_callback_for_static_fields(&wrapper,
1443 obj,
1444 cb,
1445 (void*)user_data());
1446 } else {
1447 res = invoke_primitive_field_callback_for_instance_fields(&wrapper,
1448 obj,
1449 cb,
1450 (void*)user_data());
1451 }
1452 if (check_flags_for_abort(res)) return;
1453 }
1454
1455 // string callback
1456 if (!is_array &&
1457 callbacks()->string_primitive_value_callback != NULL &&
1458 obj->klass() == SystemDictionary::String_klass()) {
1459 jint res = invoke_string_value_callback(
1460 callbacks()->string_primitive_value_callback,
1461 &wrapper,
1462 obj,
1463 (void*)user_data() );
1464 if (check_flags_for_abort(res)) return;
1465 }
1466
1467 // array callback
1468 if (is_array &&
1469 callbacks()->array_primitive_value_callback != NULL &&
1470 obj->is_typeArray()) {
1471 jint res = invoke_array_primitive_value_callback(
1472 callbacks()->array_primitive_value_callback,
1473 &wrapper,
1474 obj,
1475 (void*)user_data() );
1476 if (check_flags_for_abort(res)) return;
1477 }
1478 };
1479
1480
1481 // Deprecated function to iterate over all objects in the heap
1482 void JvmtiTagMap::iterate_over_heap(jvmtiHeapObjectFilter object_filter,
1483 Klass* klass,
1484 jvmtiHeapObjectCallback heap_object_callback,
1485 const void* user_data)
1486 {
1487 MutexLocker ml(Heap_lock);
1488 IterateOverHeapObjectClosure blk(this,
1489 klass,
1490 object_filter,
1491 heap_object_callback,
1492 user_data);
1493 VM_HeapIterateOperation op(&blk);
1494 VMThread::execute(&op);
1495 }
1496
1497
1498 // Iterates over all objects in the heap
1499 void JvmtiTagMap::iterate_through_heap(jint heap_filter,
1500 Klass* klass,
1501 const jvmtiHeapCallbacks* callbacks,
1502 const void* user_data)
1503 {
1504 MutexLocker ml(Heap_lock);
1505 IterateThroughHeapObjectClosure blk(this,
1506 klass,
1507 heap_filter,
1508 callbacks,
1509 user_data);
1510 VM_HeapIterateOperation op(&blk);
1511 VMThread::execute(&op);
1512 }
1513
1514 // support class for get_objects_with_tags
1515
1516 class TagObjectCollector : public JvmtiTagHashmapEntryClosure {
1517 private:
1518 JvmtiEnv* _env;
1519 jlong* _tags;
1520 jint _tag_count;
1521
1522 GrowableArray<jobject>* _object_results; // collected objects (JNI weak refs)
1523 GrowableArray<uint64_t>* _tag_results; // collected tags
1524
1525 public:
1526 TagObjectCollector(JvmtiEnv* env, const jlong* tags, jint tag_count) {
1527 _env = env;
1528 _tags = (jlong*)tags;
1529 _tag_count = tag_count;
1530 _object_results = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<jobject>(1,true);
1531 _tag_results = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<uint64_t>(1,true);
1532 }
1533
1534 ~TagObjectCollector() {
1535 delete _object_results;
1536 delete _tag_results;
1537 }
1538
1539 // for each tagged object check if the tag value matches
1540 // - if it matches then we create a JNI local reference to the object
1541 // and record the reference and tag value.
1542 //
1543 void do_entry(JvmtiTagHashmapEntry* entry) {
1544 for (int i=0; i<_tag_count; i++) {
1545 if (_tags[i] == entry->tag()) {
1546 // The reference in this tag map could be the only (implicitly weak)
1547 // reference to that object. If we hand it out, we need to keep it live wrt
1548 // SATB marking similar to other j.l.ref.Reference referents. This is
1549 // achieved by using a phantom load in the object() accessor.
1550 oop o = entry->object();
1551 assert(o != NULL && Universe::heap()->is_in_reserved(o), "sanity check");
1552 jobject ref = JNIHandles::make_local(JavaThread::current(), o);
1553 _object_results->append(ref);
1554 _tag_results->append((uint64_t)entry->tag());
1555 }
1556 }
1557 }
1558
1559 // return the results from the collection
1560 //
1561 jvmtiError result(jint* count_ptr, jobject** object_result_ptr, jlong** tag_result_ptr) {
1562 jvmtiError error;
1563 int count = _object_results->length();
1564 assert(count >= 0, "sanity check");
1565
1566 // if object_result_ptr is not NULL then allocate the result and copy
1567 // in the object references.
1568 if (object_result_ptr != NULL) {
1569 error = _env->Allocate(count * sizeof(jobject), (unsigned char**)object_result_ptr);
1570 if (error != JVMTI_ERROR_NONE) {
1571 return error;
1572 }
1573 for (int i=0; i<count; i++) {
1574 (*object_result_ptr)[i] = _object_results->at(i);
1575 }
1576 }
1577
1578 // if tag_result_ptr is not NULL then allocate the result and copy
1579 // in the tag values.
1580 if (tag_result_ptr != NULL) {
1581 error = _env->Allocate(count * sizeof(jlong), (unsigned char**)tag_result_ptr);
1582 if (error != JVMTI_ERROR_NONE) {
1583 if (object_result_ptr != NULL) {
1584 _env->Deallocate((unsigned char*)object_result_ptr);
1585 }
1586 return error;
1587 }
1588 for (int i=0; i<count; i++) {
1589 (*tag_result_ptr)[i] = (jlong)_tag_results->at(i);
1590 }
1591 }
1592
1593 *count_ptr = count;
1594 return JVMTI_ERROR_NONE;
1595 }
1596 };
1597
1598 // return the list of objects with the specified tags
1599 jvmtiError JvmtiTagMap::get_objects_with_tags(const jlong* tags,
1600 jint count, jint* count_ptr, jobject** object_result_ptr, jlong** tag_result_ptr) {
1601
1602 TagObjectCollector collector(env(), tags, count);
1603 {
1604 // iterate over all tagged objects
1605 MutexLocker ml(lock());
1606 entry_iterate(&collector);
1607 }
1608 return collector.result(count_ptr, object_result_ptr, tag_result_ptr);
1609 }
1610
1611
1612 // ObjectMarker is used to support the marking objects when walking the
1613 // heap.
1614 //
1615 // This implementation uses the existing mark bits in an object for
1616 // marking. Objects that are marked must later have their headers restored.
1617 // As most objects are unlocked and don't have their identity hash computed
1618 // we don't have to save their headers. Instead we save the headers that
1619 // are "interesting". Later when the headers are restored this implementation
1620 // restores all headers to their initial value and then restores the few
1621 // objects that had interesting headers.
1622 //
1623 // Future work: This implementation currently uses growable arrays to save
1624 // the oop and header of interesting objects. As an optimization we could
1625 // use the same technique as the GC and make use of the unused area
1626 // between top() and end().
1627 //
1628
1629 // An ObjectClosure used to restore the mark bits of an object
1630 class RestoreMarksClosure : public ObjectClosure {
1631 public:
1632 void do_object(oop o) {
1633 if (o != NULL) {
1634 markOop mark = o->mark();
1635 if (mark->is_marked()) {
1636 o->init_mark();
1637 }
1638 }
1639 }
1640 };
1641
1642 // ObjectMarker provides the mark and visited functions
1643 class ObjectMarker : AllStatic {
1644 private:
1645 // saved headers
1646 static GrowableArray<oop>* _saved_oop_stack;
1647 static GrowableArray<markOop>* _saved_mark_stack;
1648 static bool _needs_reset; // do we need to reset mark bits?
1649
1650 public:
1651 static void init(); // initialize
1652 static void done(); // clean-up
1653
1654 static inline void mark(oop o); // mark an object
1655 static inline bool visited(oop o); // check if object has been visited
1656
1657 static inline bool needs_reset() { return _needs_reset; }
1658 static inline void set_needs_reset(bool v) { _needs_reset = v; }
1659 };
1660
1661 GrowableArray<oop>* ObjectMarker::_saved_oop_stack = NULL;
1662 GrowableArray<markOop>* ObjectMarker::_saved_mark_stack = NULL;
1663 bool ObjectMarker::_needs_reset = true; // need to reset mark bits by default
1664
1665 // initialize ObjectMarker - prepares for object marking
1666 void ObjectMarker::init() {
1667 assert(Thread::current()->is_VM_thread(), "must be VMThread");
1668
1669 // prepare heap for iteration
1670 Universe::heap()->ensure_parsability(false); // no need to retire TLABs
1671
1672 // create stacks for interesting headers
1673 _saved_mark_stack = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<markOop>(4000, true);
1674 _saved_oop_stack = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<oop>(4000, true);
1675
1676 if (UseBiasedLocking) {
1677 BiasedLocking::preserve_marks();
1678 }
1679 }
1680
1681 // Object marking is done so restore object headers
1682 void ObjectMarker::done() {
1683 // iterate over all objects and restore the mark bits to
1684 // their initial value
1685 RestoreMarksClosure blk;
1686 if (needs_reset()) {
1687 Universe::heap()->object_iterate(&blk);
1688 } else {
1689 // We don't need to reset mark bits on this call, but reset the
1690 // flag to the default for the next call.
1691 set_needs_reset(true);
1692 }
1693
1694 // now restore the interesting headers
1695 for (int i = 0; i < _saved_oop_stack->length(); i++) {
1696 oop o = _saved_oop_stack->at(i);
1697 markOop mark = _saved_mark_stack->at(i);
1698 o->set_mark(mark);
1699 }
1700
1701 if (UseBiasedLocking) {
1702 BiasedLocking::restore_marks();
1703 }
1704
1705 // free the stacks
1706 delete _saved_oop_stack;
1707 delete _saved_mark_stack;
1708 }
1709
1710 // mark an object
1711 inline void ObjectMarker::mark(oop o) {
1712 assert(Universe::heap()->is_in(o), "sanity check");
1713 assert(!o->mark()->is_marked(), "should only mark an object once");
1714
1715 // object's mark word
1716 markOop mark = o->mark();
1717
1718 if (mark->must_be_preserved(o)) {
1719 _saved_mark_stack->push(mark);
1720 _saved_oop_stack->push(o);
1721 }
1722
1723 // mark the object
1724 o->set_mark(markOopDesc::prototype()->set_marked());
1725 }
1726
1727 // return true if object is marked
1728 inline bool ObjectMarker::visited(oop o) {
1729 return o->mark()->is_marked();
1730 }
1731
1732 // Stack allocated class to help ensure that ObjectMarker is used
1733 // correctly. Constructor initializes ObjectMarker, destructor calls
1734 // ObjectMarker's done() function to restore object headers.
1735 class ObjectMarkerController : public StackObj {
1736 public:
1737 ObjectMarkerController() {
1738 ObjectMarker::init();
1739 }
1740 ~ObjectMarkerController() {
1741 ObjectMarker::done();
1742 }
1743 };
1744
1745
1746 // helper to map a jvmtiHeapReferenceKind to an old style jvmtiHeapRootKind
1747 // (not performance critical as only used for roots)
1748 static jvmtiHeapRootKind toJvmtiHeapRootKind(jvmtiHeapReferenceKind kind) {
1749 switch (kind) {
1750 case JVMTI_HEAP_REFERENCE_JNI_GLOBAL: return JVMTI_HEAP_ROOT_JNI_GLOBAL;
1751 case JVMTI_HEAP_REFERENCE_SYSTEM_CLASS: return JVMTI_HEAP_ROOT_SYSTEM_CLASS;
1752 case JVMTI_HEAP_REFERENCE_MONITOR: return JVMTI_HEAP_ROOT_MONITOR;
1753 case JVMTI_HEAP_REFERENCE_STACK_LOCAL: return JVMTI_HEAP_ROOT_STACK_LOCAL;
1754 case JVMTI_HEAP_REFERENCE_JNI_LOCAL: return JVMTI_HEAP_ROOT_JNI_LOCAL;
1755 case JVMTI_HEAP_REFERENCE_THREAD: return JVMTI_HEAP_ROOT_THREAD;
1756 case JVMTI_HEAP_REFERENCE_OTHER: return JVMTI_HEAP_ROOT_OTHER;
1757 default: ShouldNotReachHere(); return JVMTI_HEAP_ROOT_OTHER;
1758 }
1759 }
1760
1761 // Base class for all heap walk contexts. The base class maintains a flag
1762 // to indicate if the context is valid or not.
1763 class HeapWalkContext VALUE_OBJ_CLASS_SPEC {
1764 private:
1765 bool _valid;
1766 public:
1767 HeapWalkContext(bool valid) { _valid = valid; }
1768 void invalidate() { _valid = false; }
1769 bool is_valid() const { return _valid; }
1770 };
1771
1772 // A basic heap walk context for the deprecated heap walking functions.
1773 // The context for a basic heap walk are the callbacks and fields used by
1774 // the referrer caching scheme.
1775 class BasicHeapWalkContext: public HeapWalkContext {
1776 private:
1777 jvmtiHeapRootCallback _heap_root_callback;
1778 jvmtiStackReferenceCallback _stack_ref_callback;
1779 jvmtiObjectReferenceCallback _object_ref_callback;
1780
1781 // used for caching
1782 oop _last_referrer;
1783 jlong _last_referrer_tag;
1784
1785 public:
1786 BasicHeapWalkContext() : HeapWalkContext(false) { }
1787
1788 BasicHeapWalkContext(jvmtiHeapRootCallback heap_root_callback,
1789 jvmtiStackReferenceCallback stack_ref_callback,
1790 jvmtiObjectReferenceCallback object_ref_callback) :
1791 HeapWalkContext(true),
1792 _heap_root_callback(heap_root_callback),
1793 _stack_ref_callback(stack_ref_callback),
1794 _object_ref_callback(object_ref_callback),
1795 _last_referrer(NULL),
1796 _last_referrer_tag(0) {
1797 }
1798
1799 // accessors
1800 jvmtiHeapRootCallback heap_root_callback() const { return _heap_root_callback; }
1801 jvmtiStackReferenceCallback stack_ref_callback() const { return _stack_ref_callback; }
1802 jvmtiObjectReferenceCallback object_ref_callback() const { return _object_ref_callback; }
1803
1804 oop last_referrer() const { return _last_referrer; }
1805 void set_last_referrer(oop referrer) { _last_referrer = referrer; }
1806 jlong last_referrer_tag() const { return _last_referrer_tag; }
1807 void set_last_referrer_tag(jlong value) { _last_referrer_tag = value; }
1808 };
1809
1810 // The advanced heap walk context for the FollowReferences functions.
1811 // The context is the callbacks, and the fields used for filtering.
1812 class AdvancedHeapWalkContext: public HeapWalkContext {
1813 private:
1814 jint _heap_filter;
1815 Klass* _klass_filter;
1816 const jvmtiHeapCallbacks* _heap_callbacks;
1817
1818 public:
1819 AdvancedHeapWalkContext() : HeapWalkContext(false) { }
1820
1821 AdvancedHeapWalkContext(jint heap_filter,
1822 Klass* klass_filter,
1823 const jvmtiHeapCallbacks* heap_callbacks) :
1824 HeapWalkContext(true),
1825 _heap_filter(heap_filter),
1826 _klass_filter(klass_filter),
1827 _heap_callbacks(heap_callbacks) {
1828 }
1829
1830 // accessors
1831 jint heap_filter() const { return _heap_filter; }
1832 Klass* klass_filter() const { return _klass_filter; }
1833
1834 const jvmtiHeapReferenceCallback heap_reference_callback() const {
1835 return _heap_callbacks->heap_reference_callback;
1836 };
1837 const jvmtiPrimitiveFieldCallback primitive_field_callback() const {
1838 return _heap_callbacks->primitive_field_callback;
1839 }
1840 const jvmtiArrayPrimitiveValueCallback array_primitive_value_callback() const {
1841 return _heap_callbacks->array_primitive_value_callback;
1842 }
1843 const jvmtiStringPrimitiveValueCallback string_primitive_value_callback() const {
1844 return _heap_callbacks->string_primitive_value_callback;
1845 }
1846 };
1847
1848 // The CallbackInvoker is a class with static functions that the heap walk can call
1849 // into to invoke callbacks. It works in one of two modes. The "basic" mode is
1850 // used for the deprecated IterateOverReachableObjects functions. The "advanced"
1851 // mode is for the newer FollowReferences function which supports a lot of
1852 // additional callbacks.
1853 class CallbackInvoker : AllStatic {
1854 private:
1855 // heap walk styles
1856 enum { basic, advanced };
1857 static int _heap_walk_type;
1858 static bool is_basic_heap_walk() { return _heap_walk_type == basic; }
1859 static bool is_advanced_heap_walk() { return _heap_walk_type == advanced; }
1860
1861 // context for basic style heap walk
1862 static BasicHeapWalkContext _basic_context;
1863 static BasicHeapWalkContext* basic_context() {
1864 assert(_basic_context.is_valid(), "invalid");
1865 return &_basic_context;
1866 }
1867
1868 // context for advanced style heap walk
1869 static AdvancedHeapWalkContext _advanced_context;
1870 static AdvancedHeapWalkContext* advanced_context() {
1871 assert(_advanced_context.is_valid(), "invalid");
1872 return &_advanced_context;
1873 }
1874
1875 // context needed for all heap walks
1876 static JvmtiTagMap* _tag_map;
1877 static const void* _user_data;
1878 static GrowableArray<oop>* _visit_stack;
1879
1880 // accessors
1881 static JvmtiTagMap* tag_map() { return _tag_map; }
1882 static const void* user_data() { return _user_data; }
1883 static GrowableArray<oop>* visit_stack() { return _visit_stack; }
1884
1885 // if the object hasn't been visited then push it onto the visit stack
1886 // so that it will be visited later
1887 static inline bool check_for_visit(oop obj) {
1888 if (!ObjectMarker::visited(obj)) visit_stack()->push(obj);
1889 return true;
1890 }
1891
1892 // invoke basic style callbacks
1893 static inline bool invoke_basic_heap_root_callback
1894 (jvmtiHeapRootKind root_kind, oop obj);
1895 static inline bool invoke_basic_stack_ref_callback
1896 (jvmtiHeapRootKind root_kind, jlong thread_tag, jint depth, jmethodID method,
1897 int slot, oop obj);
1898 static inline bool invoke_basic_object_reference_callback
1899 (jvmtiObjectReferenceKind ref_kind, oop referrer, oop referree, jint index);
1900
1901 // invoke advanced style callbacks
1902 static inline bool invoke_advanced_heap_root_callback
1903 (jvmtiHeapReferenceKind ref_kind, oop obj);
1904 static inline bool invoke_advanced_stack_ref_callback
1905 (jvmtiHeapReferenceKind ref_kind, jlong thread_tag, jlong tid, int depth,
1906 jmethodID method, jlocation bci, jint slot, oop obj);
1907 static inline bool invoke_advanced_object_reference_callback
1908 (jvmtiHeapReferenceKind ref_kind, oop referrer, oop referree, jint index);
1909
1910 // used to report the value of primitive fields
1911 static inline bool report_primitive_field
1912 (jvmtiHeapReferenceKind ref_kind, oop obj, jint index, address addr, char type);
1913
1914 public:
1915 // initialize for basic mode
1916 static void initialize_for_basic_heap_walk(JvmtiTagMap* tag_map,
1917 GrowableArray<oop>* visit_stack,
1918 const void* user_data,
1919 BasicHeapWalkContext context);
1920
1921 // initialize for advanced mode
1922 static void initialize_for_advanced_heap_walk(JvmtiTagMap* tag_map,
1923 GrowableArray<oop>* visit_stack,
1924 const void* user_data,
1925 AdvancedHeapWalkContext context);
1926
1927 // functions to report roots
1928 static inline bool report_simple_root(jvmtiHeapReferenceKind kind, oop o);
1929 static inline bool report_jni_local_root(jlong thread_tag, jlong tid, jint depth,
1930 jmethodID m, oop o);
1931 static inline bool report_stack_ref_root(jlong thread_tag, jlong tid, jint depth,
1932 jmethodID method, jlocation bci, jint slot, oop o);
1933
1934 // functions to report references
1935 static inline bool report_array_element_reference(oop referrer, oop referree, jint index);
1936 static inline bool report_class_reference(oop referrer, oop referree);
1937 static inline bool report_class_loader_reference(oop referrer, oop referree);
1938 static inline bool report_signers_reference(oop referrer, oop referree);
1939 static inline bool report_protection_domain_reference(oop referrer, oop referree);
1940 static inline bool report_superclass_reference(oop referrer, oop referree);
1941 static inline bool report_interface_reference(oop referrer, oop referree);
1942 static inline bool report_static_field_reference(oop referrer, oop referree, jint slot);
1943 static inline bool report_field_reference(oop referrer, oop referree, jint slot);
1944 static inline bool report_constant_pool_reference(oop referrer, oop referree, jint index);
1945 static inline bool report_primitive_array_values(oop array);
1946 static inline bool report_string_value(oop str);
1947 static inline bool report_primitive_instance_field(oop o, jint index, address value, char type);
1948 static inline bool report_primitive_static_field(oop o, jint index, address value, char type);
1949 };
1950
1951 // statics
1952 int CallbackInvoker::_heap_walk_type;
1953 BasicHeapWalkContext CallbackInvoker::_basic_context;
1954 AdvancedHeapWalkContext CallbackInvoker::_advanced_context;
1955 JvmtiTagMap* CallbackInvoker::_tag_map;
1956 const void* CallbackInvoker::_user_data;
1957 GrowableArray<oop>* CallbackInvoker::_visit_stack;
1958
1959 // initialize for basic heap walk (IterateOverReachableObjects et al)
1960 void CallbackInvoker::initialize_for_basic_heap_walk(JvmtiTagMap* tag_map,
1961 GrowableArray<oop>* visit_stack,
1962 const void* user_data,
1963 BasicHeapWalkContext context) {
1964 _tag_map = tag_map;
1965 _visit_stack = visit_stack;
1966 _user_data = user_data;
1967 _basic_context = context;
1968 _advanced_context.invalidate(); // will trigger assertion if used
1969 _heap_walk_type = basic;
1970 }
1971
1972 // initialize for advanced heap walk (FollowReferences)
1973 void CallbackInvoker::initialize_for_advanced_heap_walk(JvmtiTagMap* tag_map,
1974 GrowableArray<oop>* visit_stack,
1975 const void* user_data,
1976 AdvancedHeapWalkContext context) {
1977 _tag_map = tag_map;
1978 _visit_stack = visit_stack;
1979 _user_data = user_data;
1980 _advanced_context = context;
1981 _basic_context.invalidate(); // will trigger assertion if used
1982 _heap_walk_type = advanced;
1983 }
1984
1985
1986 // invoke basic style heap root callback
1987 inline bool CallbackInvoker::invoke_basic_heap_root_callback(jvmtiHeapRootKind root_kind, oop obj) {
1988 assert(ServiceUtil::visible_oop(obj), "checking");
1989
1990 // if we heap roots should be reported
1991 jvmtiHeapRootCallback cb = basic_context()->heap_root_callback();
1992 if (cb == NULL) {
1993 return check_for_visit(obj);
1994 }
1995
1996 CallbackWrapper wrapper(tag_map(), obj);
1997 jvmtiIterationControl control = (*cb)(root_kind,
1998 wrapper.klass_tag(),
1999 wrapper.obj_size(),
2000 wrapper.obj_tag_p(),
2001 (void*)user_data());
2002 // push root to visit stack when following references
2003 if (control == JVMTI_ITERATION_CONTINUE &&
2004 basic_context()->object_ref_callback() != NULL) {
2005 visit_stack()->push(obj);
2006 }
2007 return control != JVMTI_ITERATION_ABORT;
2008 }
2009
2010 // invoke basic style stack ref callback
2011 inline bool CallbackInvoker::invoke_basic_stack_ref_callback(jvmtiHeapRootKind root_kind,
2012 jlong thread_tag,
2013 jint depth,
2014 jmethodID method,
2015 int slot,
2016 oop obj) {
2017 assert(ServiceUtil::visible_oop(obj), "checking");
2018
2019 // if we stack refs should be reported
2020 jvmtiStackReferenceCallback cb = basic_context()->stack_ref_callback();
2021 if (cb == NULL) {
2022 return check_for_visit(obj);
2023 }
2024
2025 CallbackWrapper wrapper(tag_map(), obj);
2026 jvmtiIterationControl control = (*cb)(root_kind,
2027 wrapper.klass_tag(),
2028 wrapper.obj_size(),
2029 wrapper.obj_tag_p(),
2030 thread_tag,
2031 depth,
2032 method,
2033 slot,
2034 (void*)user_data());
2035 // push root to visit stack when following references
2036 if (control == JVMTI_ITERATION_CONTINUE &&
2037 basic_context()->object_ref_callback() != NULL) {
2038 visit_stack()->push(obj);
2039 }
2040 return control != JVMTI_ITERATION_ABORT;
2041 }
2042
2043 // invoke basic style object reference callback
2044 inline bool CallbackInvoker::invoke_basic_object_reference_callback(jvmtiObjectReferenceKind ref_kind,
2045 oop referrer,
2046 oop referree,
2047 jint index) {
2048
2049 assert(ServiceUtil::visible_oop(referrer), "checking");
2050 assert(ServiceUtil::visible_oop(referree), "checking");
2051
2052 BasicHeapWalkContext* context = basic_context();
2053
2054 // callback requires the referrer's tag. If it's the same referrer
2055 // as the last call then we use the cached value.
2056 jlong referrer_tag;
2057 if (referrer == context->last_referrer()) {
2058 referrer_tag = context->last_referrer_tag();
2059 } else {
2060 referrer_tag = tag_for(tag_map(), referrer);
2061 }
2062
2063 // do the callback
2064 CallbackWrapper wrapper(tag_map(), referree);
2065 jvmtiObjectReferenceCallback cb = context->object_ref_callback();
2066 jvmtiIterationControl control = (*cb)(ref_kind,
2067 wrapper.klass_tag(),
2068 wrapper.obj_size(),
2069 wrapper.obj_tag_p(),
2070 referrer_tag,
2071 index,
2072 (void*)user_data());
2073
2074 // record referrer and referrer tag. For self-references record the
2075 // tag value from the callback as this might differ from referrer_tag.
2076 context->set_last_referrer(referrer);
2077 if (referrer == referree) {
2078 context->set_last_referrer_tag(*wrapper.obj_tag_p());
2079 } else {
2080 context->set_last_referrer_tag(referrer_tag);
2081 }
2082
2083 if (control == JVMTI_ITERATION_CONTINUE) {
2084 return check_for_visit(referree);
2085 } else {
2086 return control != JVMTI_ITERATION_ABORT;
2087 }
2088 }
2089
2090 // invoke advanced style heap root callback
2091 inline bool CallbackInvoker::invoke_advanced_heap_root_callback(jvmtiHeapReferenceKind ref_kind,
2092 oop obj) {
2093 assert(ServiceUtil::visible_oop(obj), "checking");
2094
2095 AdvancedHeapWalkContext* context = advanced_context();
2096
2097 // check that callback is provided
2098 jvmtiHeapReferenceCallback cb = context->heap_reference_callback();
2099 if (cb == NULL) {
2100 return check_for_visit(obj);
2101 }
2102
2103 // apply class filter
2104 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
2105 return check_for_visit(obj);
2106 }
2107
2108 // setup the callback wrapper
2109 CallbackWrapper wrapper(tag_map(), obj);
2110
2111 // apply tag filter
2112 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2113 wrapper.klass_tag(),
2114 context->heap_filter())) {
2115 return check_for_visit(obj);
2116 }
2117
2118 // for arrays we need the length, otherwise -1
2119 jint len = (jint)(obj->is_array() ? arrayOop(obj)->length() : -1);
2120
2121 // invoke the callback
2122 jint res = (*cb)(ref_kind,
2123 NULL, // referrer info
2124 wrapper.klass_tag(),
2125 0, // referrer_class_tag is 0 for heap root
2126 wrapper.obj_size(),
2127 wrapper.obj_tag_p(),
2128 NULL, // referrer_tag_p
2129 len,
2130 (void*)user_data());
2131 if (res & JVMTI_VISIT_ABORT) {
2132 return false;// referrer class tag
2133 }
2134 if (res & JVMTI_VISIT_OBJECTS) {
2135 check_for_visit(obj);
2136 }
2137 return true;
2138 }
2139
2140 // report a reference from a thread stack to an object
2141 inline bool CallbackInvoker::invoke_advanced_stack_ref_callback(jvmtiHeapReferenceKind ref_kind,
2142 jlong thread_tag,
2143 jlong tid,
2144 int depth,
2145 jmethodID method,
2146 jlocation bci,
2147 jint slot,
2148 oop obj) {
2149 assert(ServiceUtil::visible_oop(obj), "checking");
2150
2151 AdvancedHeapWalkContext* context = advanced_context();
2152
2153 // check that callback is provider
2154 jvmtiHeapReferenceCallback cb = context->heap_reference_callback();
2155 if (cb == NULL) {
2156 return check_for_visit(obj);
2157 }
2158
2159 // apply class filter
2160 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
2161 return check_for_visit(obj);
2162 }
2163
2164 // setup the callback wrapper
2165 CallbackWrapper wrapper(tag_map(), obj);
2166
2167 // apply tag filter
2168 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2169 wrapper.klass_tag(),
2170 context->heap_filter())) {
2171 return check_for_visit(obj);
2172 }
2173
2174 // setup the referrer info
2175 jvmtiHeapReferenceInfo reference_info;
2176 reference_info.stack_local.thread_tag = thread_tag;
2177 reference_info.stack_local.thread_id = tid;
2178 reference_info.stack_local.depth = depth;
2179 reference_info.stack_local.method = method;
2180 reference_info.stack_local.location = bci;
2181 reference_info.stack_local.slot = slot;
2182
2183 // for arrays we need the length, otherwise -1
2184 jint len = (jint)(obj->is_array() ? arrayOop(obj)->length() : -1);
2185
2186 // call into the agent
2187 int res = (*cb)(ref_kind,
2188 &reference_info,
2189 wrapper.klass_tag(),
2190 0, // referrer_class_tag is 0 for heap root (stack)
2191 wrapper.obj_size(),
2192 wrapper.obj_tag_p(),
2193 NULL, // referrer_tag is 0 for root
2194 len,
2195 (void*)user_data());
2196
2197 if (res & JVMTI_VISIT_ABORT) {
2198 return false;
2199 }
2200 if (res & JVMTI_VISIT_OBJECTS) {
2201 check_for_visit(obj);
2202 }
2203 return true;
2204 }
2205
2206 // This mask is used to pass reference_info to a jvmtiHeapReferenceCallback
2207 // only for ref_kinds defined by the JVM TI spec. Otherwise, NULL is passed.
2208 #define REF_INFO_MASK ((1 << JVMTI_HEAP_REFERENCE_FIELD) \
2209 | (1 << JVMTI_HEAP_REFERENCE_STATIC_FIELD) \
2210 | (1 << JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT) \
2211 | (1 << JVMTI_HEAP_REFERENCE_CONSTANT_POOL) \
2212 | (1 << JVMTI_HEAP_REFERENCE_STACK_LOCAL) \
2213 | (1 << JVMTI_HEAP_REFERENCE_JNI_LOCAL))
2214
2215 // invoke the object reference callback to report a reference
2216 inline bool CallbackInvoker::invoke_advanced_object_reference_callback(jvmtiHeapReferenceKind ref_kind,
2217 oop referrer,
2218 oop obj,
2219 jint index)
2220 {
2221 // field index is only valid field in reference_info
2222 static jvmtiHeapReferenceInfo reference_info = { 0 };
2223
2224 assert(ServiceUtil::visible_oop(referrer), "checking");
2225 assert(ServiceUtil::visible_oop(obj), "checking");
2226
2227 AdvancedHeapWalkContext* context = advanced_context();
2228
2229 // check that callback is provider
2230 jvmtiHeapReferenceCallback cb = context->heap_reference_callback();
2231 if (cb == NULL) {
2232 return check_for_visit(obj);
2233 }
2234
2235 // apply class filter
2236 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
2237 return check_for_visit(obj);
2238 }
2239
2240 // setup the callback wrapper
2241 TwoOopCallbackWrapper wrapper(tag_map(), referrer, obj);
2242
2243 // apply tag filter
2244 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2245 wrapper.klass_tag(),
2246 context->heap_filter())) {
2247 return check_for_visit(obj);
2248 }
2249
2250 // field index is only valid field in reference_info
2251 reference_info.field.index = index;
2252
2253 // for arrays we need the length, otherwise -1
2254 jint len = (jint)(obj->is_array() ? arrayOop(obj)->length() : -1);
2255
2256 // invoke the callback
2257 int res = (*cb)(ref_kind,
2258 (REF_INFO_MASK & (1 << ref_kind)) ? &reference_info : NULL,
2259 wrapper.klass_tag(),
2260 wrapper.referrer_klass_tag(),
2261 wrapper.obj_size(),
2262 wrapper.obj_tag_p(),
2263 wrapper.referrer_tag_p(),
2264 len,
2265 (void*)user_data());
2266
2267 if (res & JVMTI_VISIT_ABORT) {
2268 return false;
2269 }
2270 if (res & JVMTI_VISIT_OBJECTS) {
2271 check_for_visit(obj);
2272 }
2273 return true;
2274 }
2275
2276 // report a "simple root"
2277 inline bool CallbackInvoker::report_simple_root(jvmtiHeapReferenceKind kind, oop obj) {
2278 assert(kind != JVMTI_HEAP_REFERENCE_STACK_LOCAL &&
2279 kind != JVMTI_HEAP_REFERENCE_JNI_LOCAL, "not a simple root");
2280 assert(ServiceUtil::visible_oop(obj), "checking");
2281
2282 if (is_basic_heap_walk()) {
2283 // map to old style root kind
2284 jvmtiHeapRootKind root_kind = toJvmtiHeapRootKind(kind);
2285 return invoke_basic_heap_root_callback(root_kind, obj);
2286 } else {
2287 assert(is_advanced_heap_walk(), "wrong heap walk type");
2288 return invoke_advanced_heap_root_callback(kind, obj);
2289 }
2290 }
2291
2292
2293 // invoke the primitive array values
2294 inline bool CallbackInvoker::report_primitive_array_values(oop obj) {
2295 assert(obj->is_typeArray(), "not a primitive array");
2296
2297 AdvancedHeapWalkContext* context = advanced_context();
2298 assert(context->array_primitive_value_callback() != NULL, "no callback");
2299
2300 // apply class filter
2301 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
2302 return true;
2303 }
2304
2305 CallbackWrapper wrapper(tag_map(), obj);
2306
2307 // apply tag filter
2308 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2309 wrapper.klass_tag(),
2310 context->heap_filter())) {
2311 return true;
2312 }
2313
2314 // invoke the callback
2315 int res = invoke_array_primitive_value_callback(context->array_primitive_value_callback(),
2316 &wrapper,
2317 obj,
2318 (void*)user_data());
2319 return (!(res & JVMTI_VISIT_ABORT));
2320 }
2321
2322 // invoke the string value callback
2323 inline bool CallbackInvoker::report_string_value(oop str) {
2324 assert(str->klass() == SystemDictionary::String_klass(), "not a string");
2325
2326 AdvancedHeapWalkContext* context = advanced_context();
2327 assert(context->string_primitive_value_callback() != NULL, "no callback");
2328
2329 // apply class filter
2330 if (is_filtered_by_klass_filter(str, context->klass_filter())) {
2331 return true;
2332 }
2333
2334 CallbackWrapper wrapper(tag_map(), str);
2335
2336 // apply tag filter
2337 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2338 wrapper.klass_tag(),
2339 context->heap_filter())) {
2340 return true;
2341 }
2342
2343 // invoke the callback
2344 int res = invoke_string_value_callback(context->string_primitive_value_callback(),
2345 &wrapper,
2346 str,
2347 (void*)user_data());
2348 return (!(res & JVMTI_VISIT_ABORT));
2349 }
2350
2351 // invoke the primitive field callback
2352 inline bool CallbackInvoker::report_primitive_field(jvmtiHeapReferenceKind ref_kind,
2353 oop obj,
2354 jint index,
2355 address addr,
2356 char type)
2357 {
2358 // for primitive fields only the index will be set
2359 static jvmtiHeapReferenceInfo reference_info = { 0 };
2360
2361 AdvancedHeapWalkContext* context = advanced_context();
2362 assert(context->primitive_field_callback() != NULL, "no callback");
2363
2364 // apply class filter
2365 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
2366 return true;
2367 }
2368
2369 CallbackWrapper wrapper(tag_map(), obj);
2370
2371 // apply tag filter
2372 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2373 wrapper.klass_tag(),
2374 context->heap_filter())) {
2375 return true;
2376 }
2377
2378 // the field index in the referrer
2379 reference_info.field.index = index;
2380
2381 // map the type
2382 jvmtiPrimitiveType value_type = (jvmtiPrimitiveType)type;
2383
2384 // setup the jvalue
2385 jvalue value;
2386 copy_to_jvalue(&value, addr, value_type);
2387
2388 jvmtiPrimitiveFieldCallback cb = context->primitive_field_callback();
2389 int res = (*cb)(ref_kind,
2390 &reference_info,
2391 wrapper.klass_tag(),
2392 wrapper.obj_tag_p(),
2393 value,
2394 value_type,
2395 (void*)user_data());
2396 return (!(res & JVMTI_VISIT_ABORT));
2397 }
2398
2399
2400 // instance field
2401 inline bool CallbackInvoker::report_primitive_instance_field(oop obj,
2402 jint index,
2403 address value,
2404 char type) {
2405 return report_primitive_field(JVMTI_HEAP_REFERENCE_FIELD,
2406 obj,
2407 index,
2408 value,
2409 type);
2410 }
2411
2412 // static field
2413 inline bool CallbackInvoker::report_primitive_static_field(oop obj,
2414 jint index,
2415 address value,
2416 char type) {
2417 return report_primitive_field(JVMTI_HEAP_REFERENCE_STATIC_FIELD,
2418 obj,
2419 index,
2420 value,
2421 type);
2422 }
2423
2424 // report a JNI local (root object) to the profiler
2425 inline bool CallbackInvoker::report_jni_local_root(jlong thread_tag, jlong tid, jint depth, jmethodID m, oop obj) {
2426 if (is_basic_heap_walk()) {
2427 return invoke_basic_stack_ref_callback(JVMTI_HEAP_ROOT_JNI_LOCAL,
2428 thread_tag,
2429 depth,
2430 m,
2431 -1,
2432 obj);
2433 } else {
2434 return invoke_advanced_stack_ref_callback(JVMTI_HEAP_REFERENCE_JNI_LOCAL,
2435 thread_tag, tid,
2436 depth,
2437 m,
2438 (jlocation)-1,
2439 -1,
2440 obj);
2441 }
2442 }
2443
2444
2445 // report a local (stack reference, root object)
2446 inline bool CallbackInvoker::report_stack_ref_root(jlong thread_tag,
2447 jlong tid,
2448 jint depth,
2449 jmethodID method,
2450 jlocation bci,
2451 jint slot,
2452 oop obj) {
2453 if (is_basic_heap_walk()) {
2454 return invoke_basic_stack_ref_callback(JVMTI_HEAP_ROOT_STACK_LOCAL,
2455 thread_tag,
2456 depth,
2457 method,
2458 slot,
2459 obj);
2460 } else {
2461 return invoke_advanced_stack_ref_callback(JVMTI_HEAP_REFERENCE_STACK_LOCAL,
2462 thread_tag,
2463 tid,
2464 depth,
2465 method,
2466 bci,
2467 slot,
2468 obj);
2469 }
2470 }
2471
2472 // report an object referencing a class.
2473 inline bool CallbackInvoker::report_class_reference(oop referrer, oop referree) {
2474 if (is_basic_heap_walk()) {
2475 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CLASS, referrer, referree, -1);
2476 } else {
2477 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_CLASS, referrer, referree, -1);
2478 }
2479 }
2480
2481 // report a class referencing its class loader.
2482 inline bool CallbackInvoker::report_class_loader_reference(oop referrer, oop referree) {
2483 if (is_basic_heap_walk()) {
2484 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CLASS_LOADER, referrer, referree, -1);
2485 } else {
2486 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_CLASS_LOADER, referrer, referree, -1);
2487 }
2488 }
2489
2490 // report a class referencing its signers.
2491 inline bool CallbackInvoker::report_signers_reference(oop referrer, oop referree) {
2492 if (is_basic_heap_walk()) {
2493 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_SIGNERS, referrer, referree, -1);
2494 } else {
2495 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_SIGNERS, referrer, referree, -1);
2496 }
2497 }
2498
2499 // report a class referencing its protection domain..
2500 inline bool CallbackInvoker::report_protection_domain_reference(oop referrer, oop referree) {
2501 if (is_basic_heap_walk()) {
2502 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_PROTECTION_DOMAIN, referrer, referree, -1);
2503 } else {
2504 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_PROTECTION_DOMAIN, referrer, referree, -1);
2505 }
2506 }
2507
2508 // report a class referencing its superclass.
2509 inline bool CallbackInvoker::report_superclass_reference(oop referrer, oop referree) {
2510 if (is_basic_heap_walk()) {
2511 // Send this to be consistent with past implementation
2512 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CLASS, referrer, referree, -1);
2513 } else {
2514 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_SUPERCLASS, referrer, referree, -1);
2515 }
2516 }
2517
2518 // report a class referencing one of its interfaces.
2519 inline bool CallbackInvoker::report_interface_reference(oop referrer, oop referree) {
2520 if (is_basic_heap_walk()) {
2521 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_INTERFACE, referrer, referree, -1);
2522 } else {
2523 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_INTERFACE, referrer, referree, -1);
2524 }
2525 }
2526
2527 // report a class referencing one of its static fields.
2528 inline bool CallbackInvoker::report_static_field_reference(oop referrer, oop referree, jint slot) {
2529 if (is_basic_heap_walk()) {
2530 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_STATIC_FIELD, referrer, referree, slot);
2531 } else {
2532 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_STATIC_FIELD, referrer, referree, slot);
2533 }
2534 }
2535
2536 // report an array referencing an element object
2537 inline bool CallbackInvoker::report_array_element_reference(oop referrer, oop referree, jint index) {
2538 if (is_basic_heap_walk()) {
2539 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_ARRAY_ELEMENT, referrer, referree, index);
2540 } else {
2541 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT, referrer, referree, index);
2542 }
2543 }
2544
2545 // report an object referencing an instance field object
2546 inline bool CallbackInvoker::report_field_reference(oop referrer, oop referree, jint slot) {
2547 if (is_basic_heap_walk()) {
2548 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_FIELD, referrer, referree, slot);
2549 } else {
2550 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_FIELD, referrer, referree, slot);
2551 }
2552 }
2553
2554 // report an array referencing an element object
2555 inline bool CallbackInvoker::report_constant_pool_reference(oop referrer, oop referree, jint index) {
2556 if (is_basic_heap_walk()) {
2557 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CONSTANT_POOL, referrer, referree, index);
2558 } else {
2559 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_CONSTANT_POOL, referrer, referree, index);
2560 }
2561 }
2562
2563 // A supporting closure used to process simple roots
2564 class SimpleRootsClosure : public OopClosure {
2565 private:
2566 jvmtiHeapReferenceKind _kind;
2567 bool _continue;
2568
2569 jvmtiHeapReferenceKind root_kind() { return _kind; }
2570
2571 public:
2572 void set_kind(jvmtiHeapReferenceKind kind) {
2573 _kind = kind;
2574 _continue = true;
2575 }
2576
2577 inline bool stopped() {
2578 return !_continue;
2579 }
2580
2581 void do_oop(oop* obj_p) {
2582 // iteration has terminated
2583 if (stopped()) {
2584 return;
2585 }
2586
2587 oop o = *obj_p;
2588 // ignore null
2589 if (o == NULL) {
2590 return;
2591 }
2592
2593 assert(Universe::heap()->is_in_reserved(o), "should be impossible");
2594
2595 jvmtiHeapReferenceKind kind = root_kind();
2596 if (kind == JVMTI_HEAP_REFERENCE_SYSTEM_CLASS) {
2597 // SystemDictionary::always_strong_oops_do reports the application
2598 // class loader as a root. We want this root to be reported as
2599 // a root kind of "OTHER" rather than "SYSTEM_CLASS".
2600 if (!o->is_instance() || !InstanceKlass::cast(o->klass())->is_mirror_instance_klass()) {
2601 kind = JVMTI_HEAP_REFERENCE_OTHER;
2602 }
2603 }
2604
2605 // some objects are ignored - in the case of simple
2606 // roots it's mostly Symbol*s that we are skipping
2607 // here.
2608 if (!ServiceUtil::visible_oop(o)) {
2609 return;
2610 }
2611
2612 // invoke the callback
2613 _continue = CallbackInvoker::report_simple_root(kind, o);
2614
2615 }
2616 virtual void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }
2617 };
2618
2619 // A supporting closure used to process JNI locals
2620 class JNILocalRootsClosure : public OopClosure {
2621 private:
2622 jlong _thread_tag;
2623 jlong _tid;
2624 jint _depth;
2625 jmethodID _method;
2626 bool _continue;
2627 public:
2628 void set_context(jlong thread_tag, jlong tid, jint depth, jmethodID method) {
2629 _thread_tag = thread_tag;
2630 _tid = tid;
2631 _depth = depth;
2632 _method = method;
2633 _continue = true;
2634 }
2635
2636 inline bool stopped() {
2637 return !_continue;
2638 }
2639
2640 void do_oop(oop* obj_p) {
2641 // iteration has terminated
2642 if (stopped()) {
2643 return;
2644 }
2645
2646 oop o = *obj_p;
2647 // ignore null
2648 if (o == NULL) {
2649 return;
2650 }
2651
2652 if (!ServiceUtil::visible_oop(o)) {
2653 return;
2654 }
2655
2656 // invoke the callback
2657 _continue = CallbackInvoker::report_jni_local_root(_thread_tag, _tid, _depth, _method, o);
2658 }
2659 virtual void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }
2660 };
2661
2662
2663 // A VM operation to iterate over objects that are reachable from
2664 // a set of roots or an initial object.
2665 //
2666 // For VM_HeapWalkOperation the set of roots used is :-
2667 //
2668 // - All JNI global references
2669 // - All inflated monitors
2670 // - All classes loaded by the boot class loader (or all classes
2671 // in the event that class unloading is disabled)
2672 // - All java threads
2673 // - For each java thread then all locals and JNI local references
2674 // on the thread's execution stack
2675 // - All visible/explainable objects from Universes::oops_do
2676 //
2677 class VM_HeapWalkOperation: public VM_Operation {
2678 private:
2679 enum {
2680 initial_visit_stack_size = 4000
2681 };
2682
2683 bool _is_advanced_heap_walk; // indicates FollowReferences
2684 JvmtiTagMap* _tag_map;
2685 Handle _initial_object;
2686 GrowableArray<oop>* _visit_stack; // the visit stack
2687
2688 bool _collecting_heap_roots; // are we collecting roots
2689 bool _following_object_refs; // are we following object references
2690
2691 bool _reporting_primitive_fields; // optional reporting
2692 bool _reporting_primitive_array_values;
2693 bool _reporting_string_values;
2694
2695 GrowableArray<oop>* create_visit_stack() {
2696 return new (ResourceObj::C_HEAP, mtInternal) GrowableArray<oop>(initial_visit_stack_size, true);
2697 }
2698
2699 // accessors
2700 bool is_advanced_heap_walk() const { return _is_advanced_heap_walk; }
2701 JvmtiTagMap* tag_map() const { return _tag_map; }
2702 Handle initial_object() const { return _initial_object; }
2703
2704 bool is_following_references() const { return _following_object_refs; }
2705
2706 bool is_reporting_primitive_fields() const { return _reporting_primitive_fields; }
2707 bool is_reporting_primitive_array_values() const { return _reporting_primitive_array_values; }
2708 bool is_reporting_string_values() const { return _reporting_string_values; }
2709
2710 GrowableArray<oop>* visit_stack() const { return _visit_stack; }
2711
2712 // iterate over the various object types
2713 inline bool iterate_over_array(oop o);
2714 inline bool iterate_over_type_array(oop o);
2715 inline bool iterate_over_class(oop o);
2716 inline bool iterate_over_object(oop o);
2717
2718 // root collection
2719 inline bool collect_simple_roots();
2720 inline bool collect_stack_roots();
2721 inline bool collect_stack_roots(JavaThread* java_thread, JNILocalRootsClosure* blk);
2722
2723 // visit an object
2724 inline bool visit(oop o);
2725
2726 public:
2727 VM_HeapWalkOperation(JvmtiTagMap* tag_map,
2728 Handle initial_object,
2729 BasicHeapWalkContext callbacks,
2730 const void* user_data);
2731
2732 VM_HeapWalkOperation(JvmtiTagMap* tag_map,
2733 Handle initial_object,
2734 AdvancedHeapWalkContext callbacks,
2735 const void* user_data);
2736
2737 ~VM_HeapWalkOperation();
2738
2739 VMOp_Type type() const { return VMOp_HeapWalkOperation; }
2740 void doit();
2741 };
2742
2743
2744 VM_HeapWalkOperation::VM_HeapWalkOperation(JvmtiTagMap* tag_map,
2745 Handle initial_object,
2746 BasicHeapWalkContext callbacks,
2747 const void* user_data) {
2748 _is_advanced_heap_walk = false;
2749 _tag_map = tag_map;
2750 _initial_object = initial_object;
2751 _following_object_refs = (callbacks.object_ref_callback() != NULL);
2752 _reporting_primitive_fields = false;
2753 _reporting_primitive_array_values = false;
2754 _reporting_string_values = false;
2755 _visit_stack = create_visit_stack();
2756
2757
2758 CallbackInvoker::initialize_for_basic_heap_walk(tag_map, _visit_stack, user_data, callbacks);
2759 }
2760
2761 VM_HeapWalkOperation::VM_HeapWalkOperation(JvmtiTagMap* tag_map,
2762 Handle initial_object,
2763 AdvancedHeapWalkContext callbacks,
2764 const void* user_data) {
2765 _is_advanced_heap_walk = true;
2766 _tag_map = tag_map;
2767 _initial_object = initial_object;
2768 _following_object_refs = true;
2769 _reporting_primitive_fields = (callbacks.primitive_field_callback() != NULL);;
2770 _reporting_primitive_array_values = (callbacks.array_primitive_value_callback() != NULL);;
2771 _reporting_string_values = (callbacks.string_primitive_value_callback() != NULL);;
2772 _visit_stack = create_visit_stack();
2773
2774 CallbackInvoker::initialize_for_advanced_heap_walk(tag_map, _visit_stack, user_data, callbacks);
2775 }
2776
2777 VM_HeapWalkOperation::~VM_HeapWalkOperation() {
2778 if (_following_object_refs) {
2779 assert(_visit_stack != NULL, "checking");
2780 delete _visit_stack;
2781 _visit_stack = NULL;
2782 }
2783 }
2784
2785 // an array references its class and has a reference to
2786 // each element in the array
2787 inline bool VM_HeapWalkOperation::iterate_over_array(oop o) {
2788 objArrayOop array = objArrayOop(o);
2789
2790 // array reference to its class
2791 oop mirror = ObjArrayKlass::cast(array->klass())->java_mirror();
2792 if (!CallbackInvoker::report_class_reference(o, mirror)) {
2793 return false;
2794 }
2795
2796 // iterate over the array and report each reference to a
2797 // non-null element
2798 for (int index=0; index<array->length(); index++) {
2799 oop elem = array->obj_at(index);
2800 if (elem == NULL) {
2801 continue;
2802 }
2803
2804 // report the array reference o[index] = elem
2805 if (!CallbackInvoker::report_array_element_reference(o, elem, index)) {
2806 return false;
2807 }
2808 }
2809 return true;
2810 }
2811
2812 // a type array references its class
2813 inline bool VM_HeapWalkOperation::iterate_over_type_array(oop o) {
2814 Klass* k = o->klass();
2815 oop mirror = k->java_mirror();
2816 if (!CallbackInvoker::report_class_reference(o, mirror)) {
2817 return false;
2818 }
2819
2820 // report the array contents if required
2821 if (is_reporting_primitive_array_values()) {
2822 if (!CallbackInvoker::report_primitive_array_values(o)) {
2823 return false;
2824 }
2825 }
2826 return true;
2827 }
2828
2829 #ifdef ASSERT
2830 // verify that a static oop field is in range
2831 static inline bool verify_static_oop(InstanceKlass* ik,
2832 oop mirror, int offset) {
2833 address obj_p = (address)mirror + offset;
2834 address start = (address)InstanceMirrorKlass::start_of_static_fields(mirror);
2835 address end = start + (java_lang_Class::static_oop_field_count(mirror) * heapOopSize);
2836 assert(end >= start, "sanity check");
2837
2838 if (obj_p >= start && obj_p < end) {
2839 return true;
2840 } else {
2841 return false;
2842 }
2843 }
2844 #endif // #ifdef ASSERT
2845
2846 // a class references its super class, interfaces, class loader, ...
2847 // and finally its static fields
2848 inline bool VM_HeapWalkOperation::iterate_over_class(oop java_class) {
2849 int i;
2850 Klass* klass = java_lang_Class::as_Klass(java_class);
2851
2852 if (klass->is_instance_klass()) {
2853 InstanceKlass* ik = InstanceKlass::cast(klass);
2854
2855 // Ignore the class if it hasn't been initialized yet
2856 if (!ik->is_linked()) {
2857 return true;
2858 }
2859
2860 // get the java mirror
2861 oop mirror = klass->java_mirror();
2862
2863 // super (only if something more interesting than java.lang.Object)
2864 Klass* java_super = ik->java_super();
2865 if (java_super != NULL && java_super != SystemDictionary::Object_klass()) {
2866 oop super = java_super->java_mirror();
2867 if (!CallbackInvoker::report_superclass_reference(mirror, super)) {
2868 return false;
2869 }
2870 }
2871
2872 // class loader
2873 oop cl = ik->class_loader();
2874 if (cl != NULL) {
2875 if (!CallbackInvoker::report_class_loader_reference(mirror, cl)) {
2876 return false;
2877 }
2878 }
2879
2880 // protection domain
2881 oop pd = ik->protection_domain();
2882 if (pd != NULL) {
2883 if (!CallbackInvoker::report_protection_domain_reference(mirror, pd)) {
2884 return false;
2885 }
2886 }
2887
2888 // signers
2889 oop signers = ik->signers();
2890 if (signers != NULL) {
2891 if (!CallbackInvoker::report_signers_reference(mirror, signers)) {
2892 return false;
2893 }
2894 }
2895
2896 // references from the constant pool
2897 {
2898 ConstantPool* pool = ik->constants();
2899 for (int i = 1; i < pool->length(); i++) {
2900 constantTag tag = pool->tag_at(i).value();
2901 if (tag.is_string() || tag.is_klass()) {
2902 oop entry;
2903 if (tag.is_string()) {
2904 entry = pool->resolved_string_at(i);
2905 // If the entry is non-null it is resolved.
2906 if (entry == NULL) continue;
2907 } else {
2908 entry = pool->resolved_klass_at(i)->java_mirror();
2909 }
2910 if (!CallbackInvoker::report_constant_pool_reference(mirror, entry, (jint)i)) {
2911 return false;
2912 }
2913 }
2914 }
2915 }
2916
2917 // interfaces
2918 // (These will already have been reported as references from the constant pool
2919 // but are specified by IterateOverReachableObjects and must be reported).
2920 Array<Klass*>* interfaces = ik->local_interfaces();
2921 for (i = 0; i < interfaces->length(); i++) {
2922 oop interf = ((Klass*)interfaces->at(i))->java_mirror();
2923 if (interf == NULL) {
2924 continue;
2925 }
2926 if (!CallbackInvoker::report_interface_reference(mirror, interf)) {
2927 return false;
2928 }
2929 }
2930
2931 // iterate over the static fields
2932
2933 ClassFieldMap* field_map = ClassFieldMap::create_map_of_static_fields(klass);
2934 for (i=0; i<field_map->field_count(); i++) {
2935 ClassFieldDescriptor* field = field_map->field_at(i);
2936 char type = field->field_type();
2937 if (!is_primitive_field_type(type)) {
2938 oop fld_o = mirror->obj_field(field->field_offset());
2939 assert(verify_static_oop(ik, mirror, field->field_offset()), "sanity check");
2940 if (fld_o != NULL) {
2941 int slot = field->field_index();
2942 if (!CallbackInvoker::report_static_field_reference(mirror, fld_o, slot)) {
2943 delete field_map;
2944 return false;
2945 }
2946 }
2947 } else {
2948 if (is_reporting_primitive_fields()) {
2949 address addr = (address)mirror + field->field_offset();
2950 int slot = field->field_index();
2951 if (!CallbackInvoker::report_primitive_static_field(mirror, slot, addr, type)) {
2952 delete field_map;
2953 return false;
2954 }
2955 }
2956 }
2957 }
2958 delete field_map;
2959
2960 return true;
2961 }
2962
2963 return true;
2964 }
2965
2966 // an object references a class and its instance fields
2967 // (static fields are ignored here as we report these as
2968 // references from the class).
2969 inline bool VM_HeapWalkOperation::iterate_over_object(oop o) {
2970 // reference to the class
2971 if (!CallbackInvoker::report_class_reference(o, o->klass()->java_mirror())) {
2972 return false;
2973 }
2974
2975 // iterate over instance fields
2976 ClassFieldMap* field_map = JvmtiCachedClassFieldMap::get_map_of_instance_fields(o);
2977 for (int i=0; i<field_map->field_count(); i++) {
2978 ClassFieldDescriptor* field = field_map->field_at(i);
2979 char type = field->field_type();
2980 if (!is_primitive_field_type(type)) {
2981 oop fld_o = o->obj_field(field->field_offset());
2982 // ignore any objects that aren't visible to profiler
2983 if (fld_o != NULL && ServiceUtil::visible_oop(fld_o)) {
2984 assert(Universe::heap()->is_in_reserved(fld_o), "unsafe code should not "
2985 "have references to Klass* anymore");
2986 int slot = field->field_index();
2987 if (!CallbackInvoker::report_field_reference(o, fld_o, slot)) {
2988 return false;
2989 }
2990 }
2991 } else {
2992 if (is_reporting_primitive_fields()) {
2993 // primitive instance field
2994 address addr = (address)o + field->field_offset();
2995 int slot = field->field_index();
2996 if (!CallbackInvoker::report_primitive_instance_field(o, slot, addr, type)) {
2997 return false;
2998 }
2999 }
3000 }
3001 }
3002
3003 // if the object is a java.lang.String
3004 if (is_reporting_string_values() &&
3005 o->klass() == SystemDictionary::String_klass()) {
3006 if (!CallbackInvoker::report_string_value(o)) {
3007 return false;
3008 }
3009 }
3010 return true;
3011 }
3012
3013
3014 // Collects all simple (non-stack) roots except for threads;
3015 // threads are handled in collect_stack_roots() as an optimization.
3016 // if there's a heap root callback provided then the callback is
3017 // invoked for each simple root.
3018 // if an object reference callback is provided then all simple
3019 // roots are pushed onto the marking stack so that they can be
3020 // processed later
3021 //
3022 inline bool VM_HeapWalkOperation::collect_simple_roots() {
3023 SimpleRootsClosure blk;
3024
3025 // JNI globals
3026 blk.set_kind(JVMTI_HEAP_REFERENCE_JNI_GLOBAL);
3027 JNIHandles::oops_do(&blk);
3028 if (blk.stopped()) {
3029 return false;
3030 }
3031
3032 // Preloaded classes and loader from the system dictionary
3033 blk.set_kind(JVMTI_HEAP_REFERENCE_SYSTEM_CLASS);
3034 SystemDictionary::always_strong_oops_do(&blk);
3035 ClassLoaderDataGraph::always_strong_oops_do(&blk, false);
3036 if (blk.stopped()) {
3037 return false;
3038 }
3039
3040 // Inflated monitors
3041 blk.set_kind(JVMTI_HEAP_REFERENCE_MONITOR);
3042 ObjectSynchronizer::oops_do(&blk);
3043 if (blk.stopped()) {
3044 return false;
3045 }
3046
3047 // threads are now handled in collect_stack_roots()
3048
3049 // Other kinds of roots maintained by HotSpot
3050 // Many of these won't be visible but others (such as instances of important
3051 // exceptions) will be visible.
3052 blk.set_kind(JVMTI_HEAP_REFERENCE_OTHER);
3053 Universe::oops_do(&blk);
3054
3055 // If there are any non-perm roots in the code cache, visit them.
3056 blk.set_kind(JVMTI_HEAP_REFERENCE_OTHER);
3057 CodeBlobToOopClosure look_in_blobs(&blk, !CodeBlobToOopClosure::FixRelocations);
3058 CodeCache::scavenge_root_nmethods_do(&look_in_blobs);
3059
3060 return true;
3061 }
3062
3063 // Walk the stack of a given thread and find all references (locals
3064 // and JNI calls) and report these as stack references
3065 inline bool VM_HeapWalkOperation::collect_stack_roots(JavaThread* java_thread,
3066 JNILocalRootsClosure* blk)
3067 {
3068 oop threadObj = java_thread->threadObj();
3069 assert(threadObj != NULL, "sanity check");
3070
3071 // only need to get the thread's tag once per thread
3072 jlong thread_tag = tag_for(_tag_map, threadObj);
3073
3074 // also need the thread id
3075 jlong tid = java_lang_Thread::thread_id(threadObj);
3076
3077
3078 if (java_thread->has_last_Java_frame()) {
3079
3080 // vframes are resource allocated
3081 Thread* current_thread = Thread::current();
3082 ResourceMark rm(current_thread);
3083 HandleMark hm(current_thread);
3084
3085 RegisterMap reg_map(java_thread);
3086 frame f = java_thread->last_frame();
3087 vframe* vf = vframe::new_vframe(&f, ®_map, java_thread);
3088
3089 bool is_top_frame = true;
3090 int depth = 0;
3091 frame* last_entry_frame = NULL;
3092
3093 while (vf != NULL) {
3094 if (vf->is_java_frame()) {
3095
3096 // java frame (interpreted, compiled, ...)
3097 javaVFrame *jvf = javaVFrame::cast(vf);
3098
3099 // the jmethodID
3100 jmethodID method = jvf->method()->jmethod_id();
3101
3102 if (!(jvf->method()->is_native())) {
3103 jlocation bci = (jlocation)jvf->bci();
3104 StackValueCollection* locals = jvf->locals();
3105 for (int slot=0; slot<locals->size(); slot++) {
3106 if (locals->at(slot)->type() == T_OBJECT) {
3107 oop o = locals->obj_at(slot)();
3108 if (o == NULL) {
3109 continue;
3110 }
3111
3112 // stack reference
3113 if (!CallbackInvoker::report_stack_ref_root(thread_tag, tid, depth, method,
3114 bci, slot, o)) {
3115 return false;
3116 }
3117 }
3118 }
3119
3120 StackValueCollection* exprs = jvf->expressions();
3121 for (int index=0; index < exprs->size(); index++) {
3122 if (exprs->at(index)->type() == T_OBJECT) {
3123 oop o = exprs->obj_at(index)();
3124 if (o == NULL) {
3125 continue;
3126 }
3127
3128 // stack reference
3129 if (!CallbackInvoker::report_stack_ref_root(thread_tag, tid, depth, method,
3130 bci, locals->size() + index, o)) {
3131 return false;
3132 }
3133 }
3134 }
3135
3136 // Follow oops from compiled nmethod
3137 if (jvf->cb() != NULL && jvf->cb()->is_nmethod()) {
3138 blk->set_context(thread_tag, tid, depth, method);
3139 jvf->cb()->as_nmethod()->oops_do(blk);
3140 }
3141 } else {
3142 blk->set_context(thread_tag, tid, depth, method);
3143 if (is_top_frame) {
3144 // JNI locals for the top frame.
3145 java_thread->active_handles()->oops_do(blk);
3146 } else {
3147 if (last_entry_frame != NULL) {
3148 // JNI locals for the entry frame
3149 assert(last_entry_frame->is_entry_frame(), "checking");
3150 last_entry_frame->entry_frame_call_wrapper()->handles()->oops_do(blk);
3151 }
3152 }
3153 }
3154 last_entry_frame = NULL;
3155 depth++;
3156 } else {
3157 // externalVFrame - for an entry frame then we report the JNI locals
3158 // when we find the corresponding javaVFrame
3159 frame* fr = vf->frame_pointer();
3160 assert(fr != NULL, "sanity check");
3161 if (fr->is_entry_frame()) {
3162 last_entry_frame = fr;
3163 }
3164 }
3165
3166 vf = vf->sender();
3167 is_top_frame = false;
3168 }
3169 } else {
3170 // no last java frame but there may be JNI locals
3171 blk->set_context(thread_tag, tid, 0, (jmethodID)NULL);
3172 java_thread->active_handles()->oops_do(blk);
3173 }
3174 return true;
3175 }
3176
3177
3178 // Collects the simple roots for all threads and collects all
3179 // stack roots - for each thread it walks the execution
3180 // stack to find all references and local JNI refs.
3181 inline bool VM_HeapWalkOperation::collect_stack_roots() {
3182 JNILocalRootsClosure blk;
3183 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thread = jtiwh.next(); ) {
3184 oop threadObj = thread->threadObj();
3185 if (threadObj != NULL && !thread->is_exiting() && !thread->is_hidden_from_external_view()) {
3186 // Collect the simple root for this thread before we
3187 // collect its stack roots
3188 if (!CallbackInvoker::report_simple_root(JVMTI_HEAP_REFERENCE_THREAD,
3189 threadObj)) {
3190 return false;
3191 }
3192 if (!collect_stack_roots(thread, &blk)) {
3193 return false;
3194 }
3195 }
3196 }
3197 return true;
3198 }
3199
3200 // visit an object
3201 // first mark the object as visited
3202 // second get all the outbound references from this object (in other words, all
3203 // the objects referenced by this object).
3204 //
3205 bool VM_HeapWalkOperation::visit(oop o) {
3206 // mark object as visited
3207 assert(!ObjectMarker::visited(o), "can't visit same object more than once");
3208 ObjectMarker::mark(o);
3209
3210 // instance
3211 if (o->is_instance()) {
3212 if (o->klass() == SystemDictionary::Class_klass()) {
3213 if (!java_lang_Class::is_primitive(o)) {
3214 // a java.lang.Class
3215 return iterate_over_class(o);
3216 }
3217 } else {
3218 return iterate_over_object(o);
3219 }
3220 }
3221
3222 // object array
3223 if (o->is_objArray()) {
3224 return iterate_over_array(o);
3225 }
3226
3227 // type array
3228 if (o->is_typeArray()) {
3229 return iterate_over_type_array(o);
3230 }
3231
3232 return true;
3233 }
3234
3235 void VM_HeapWalkOperation::doit() {
3236 ResourceMark rm;
3237 ObjectMarkerController marker;
3238 ClassFieldMapCacheMark cm;
3239
3240 assert(visit_stack()->is_empty(), "visit stack must be empty");
3241
3242 // the heap walk starts with an initial object or the heap roots
3243 if (initial_object().is_null()) {
3244 // If either collect_stack_roots() or collect_simple_roots()
3245 // returns false at this point, then there are no mark bits
3246 // to reset.
3247 ObjectMarker::set_needs_reset(false);
3248
3249 // Calling collect_stack_roots() before collect_simple_roots()
3250 // can result in a big performance boost for an agent that is
3251 // focused on analyzing references in the thread stacks.
3252 if (!collect_stack_roots()) return;
3253
3254 if (!collect_simple_roots()) return;
3255
3256 // no early return so enable heap traversal to reset the mark bits
3257 ObjectMarker::set_needs_reset(true);
3258 } else {
3259 visit_stack()->push(initial_object()());
3260 }
3261
3262 // object references required
3263 if (is_following_references()) {
3264
3265 // visit each object until all reachable objects have been
3266 // visited or the callback asked to terminate the iteration.
3267 while (!visit_stack()->is_empty()) {
3268 oop o = visit_stack()->pop();
3269 if (!ObjectMarker::visited(o)) {
3270 if (!visit(o)) {
3271 break;
3272 }
3273 }
3274 }
3275 }
3276 }
3277
3278 // iterate over all objects that are reachable from a set of roots
3279 void JvmtiTagMap::iterate_over_reachable_objects(jvmtiHeapRootCallback heap_root_callback,
3280 jvmtiStackReferenceCallback stack_ref_callback,
3281 jvmtiObjectReferenceCallback object_ref_callback,
3282 const void* user_data) {
3283 MutexLocker ml(Heap_lock);
3284 BasicHeapWalkContext context(heap_root_callback, stack_ref_callback, object_ref_callback);
3285 VM_HeapWalkOperation op(this, Handle(), context, user_data);
3286 VMThread::execute(&op);
3287 }
3288
3289 // iterate over all objects that are reachable from a given object
3290 void JvmtiTagMap::iterate_over_objects_reachable_from_object(jobject object,
3291 jvmtiObjectReferenceCallback object_ref_callback,
3292 const void* user_data) {
3293 oop obj = JNIHandles::resolve(object);
3294 Handle initial_object(Thread::current(), obj);
3295
3296 MutexLocker ml(Heap_lock);
3297 BasicHeapWalkContext context(NULL, NULL, object_ref_callback);
3298 VM_HeapWalkOperation op(this, initial_object, context, user_data);
3299 VMThread::execute(&op);
3300 }
3301
3302 // follow references from an initial object or the GC roots
3303 void JvmtiTagMap::follow_references(jint heap_filter,
3304 Klass* klass,
3305 jobject object,
3306 const jvmtiHeapCallbacks* callbacks,
3307 const void* user_data)
3308 {
3309 oop obj = JNIHandles::resolve(object);
3310 Handle initial_object(Thread::current(), obj);
3311
3312 MutexLocker ml(Heap_lock);
3313 AdvancedHeapWalkContext context(heap_filter, klass, callbacks);
3314 VM_HeapWalkOperation op(this, initial_object, context, user_data);
3315 VMThread::execute(&op);
3316 }
3317
3318
3319 void JvmtiTagMap::weak_oops_do(BoolObjectClosure* is_alive, OopClosure* f) {
3320 // No locks during VM bring-up (0 threads) and no safepoints after main
3321 // thread creation and before VMThread creation (1 thread); initial GC
3322 // verification can happen in that window which gets to here.
3323 assert(Threads::number_of_threads() <= 1 ||
3324 SafepointSynchronize::is_at_safepoint(),
3325 "must be executed at a safepoint");
3326 if (JvmtiEnv::environments_might_exist()) {
3327 JvmtiEnvIterator it;
3328 for (JvmtiEnvBase* env = it.first(); env != NULL; env = it.next(env)) {
3329 JvmtiTagMap* tag_map = env->tag_map();
3330 if (tag_map != NULL && !tag_map->is_empty()) {
3331 tag_map->do_weak_oops(is_alive, f);
3332 }
3333 }
3334 }
3335 }
3336
3337 void JvmtiTagMap::do_weak_oops(BoolObjectClosure* is_alive, OopClosure* f) {
3338
3339 // does this environment have the OBJECT_FREE event enabled
3340 bool post_object_free = env()->is_enabled(JVMTI_EVENT_OBJECT_FREE);
3341
3342 // counters used for trace message
3343 int freed = 0;
3344 int moved = 0;
3345
3346 JvmtiTagHashmap* hashmap = this->hashmap();
3347
3348 // reenable sizing (if disabled)
3349 hashmap->set_resizing_enabled(true);
3350
3351 // if the hashmap is empty then we can skip it
3352 if (hashmap->_entry_count == 0) {
3353 return;
3354 }
3355
3356 // now iterate through each entry in the table
3357
3358 JvmtiTagHashmapEntry** table = hashmap->table();
3359 int size = hashmap->size();
3360
3361 JvmtiTagHashmapEntry* delayed_add = NULL;
3362
3363 for (int pos = 0; pos < size; ++pos) {
3364 JvmtiTagHashmapEntry* entry = table[pos];
3365 JvmtiTagHashmapEntry* prev = NULL;
3366
3367 while (entry != NULL) {
3368 JvmtiTagHashmapEntry* next = entry->next();
3369
3370 // has object been GC'ed
3371 if (!is_alive->do_object_b(entry->object_peek())) {
3372 // grab the tag
3373 jlong tag = entry->tag();
3374 guarantee(tag != 0, "checking");
3375
3376 // remove GC'ed entry from hashmap and return the
3377 // entry to the free list
3378 hashmap->remove(prev, pos, entry);
3379 destroy_entry(entry);
3380
3381 // post the event to the profiler
3382 if (post_object_free) {
3383 JvmtiExport::post_object_free(env(), tag);
3384 }
3385
3386 ++freed;
3387 } else {
3388 f->do_oop(entry->object_addr());
3389 oop new_oop = entry->object_peek();
3390
3391 // if the object has moved then re-hash it and move its
3392 // entry to its new location.
3393 unsigned int new_pos = JvmtiTagHashmap::hash(new_oop, size);
3394 if (new_pos != (unsigned int)pos) {
3395 if (prev == NULL) {
3396 table[pos] = next;
3397 } else {
3398 prev->set_next(next);
3399 }
3400 if (new_pos < (unsigned int)pos) {
3401 entry->set_next(table[new_pos]);
3402 table[new_pos] = entry;
3403 } else {
3404 // Delay adding this entry to it's new position as we'd end up
3405 // hitting it again during this iteration.
3406 entry->set_next(delayed_add);
3407 delayed_add = entry;
3408 }
3409 moved++;
3410 } else {
3411 // object didn't move
3412 prev = entry;
3413 }
3414 }
3415
3416 entry = next;
3417 }
3418 }
3419
3420 // Re-add all the entries which were kept aside
3421 while (delayed_add != NULL) {
3422 JvmtiTagHashmapEntry* next = delayed_add->next();
3423 unsigned int pos = JvmtiTagHashmap::hash(delayed_add->object_peek(), size);
3424 delayed_add->set_next(table[pos]);
3425 table[pos] = delayed_add;
3426 delayed_add = next;
3427 }
3428
3429 log_debug(jvmti, objecttagging)("(%d->%d, %d freed, %d total moves)",
3430 hashmap->_entry_count + freed, hashmap->_entry_count, freed, moved);
3431 }