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