1 /*
2 * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/javaClasses.inline.hpp"
27 #include "classfile/symbolTable.hpp"
28 #include "classfile/systemDictionary.hpp"
29 #include "classfile/vmSymbols.hpp"
30 #include "code/codeCache.hpp"
31 #include "jvmtifiles/jvmtiEnv.hpp"
32 #include "memory/allocation.inline.hpp"
33 #include "memory/resourceArea.hpp"
34 #include "oops/access.inline.hpp"
35 #include "oops/arrayOop.inline.hpp"
36 #include "oops/constantPool.inline.hpp"
37 #include "oops/instanceMirrorKlass.hpp"
38 #include "oops/objArrayKlass.hpp"
39 #include "oops/objArrayOop.inline.hpp"
40 #include "oops/oop.inline.hpp"
41 #include "oops/typeArrayOop.inline.hpp"
42 #include "prims/jvmtiEventController.hpp"
43 #include "prims/jvmtiEventController.inline.hpp"
44 #include "prims/jvmtiExport.hpp"
45 #include "prims/jvmtiImpl.hpp"
46 #include "prims/jvmtiTagMap.hpp"
47 #include "runtime/biasedLocking.hpp"
48 #include "runtime/javaCalls.hpp"
49 #include "runtime/jniHandles.inline.hpp"
50 #include "runtime/mutex.hpp"
51 #include "runtime/mutexLocker.hpp"
52 #include "runtime/reflectionUtils.hpp"
53 #include "runtime/thread.inline.hpp"
54 #include "runtime/threadSMR.hpp"
55 #include "runtime/vframe.hpp"
56 #include "runtime/vmThread.hpp"
57 #include "runtime/vm_operations.hpp"
58 #include "services/serviceUtil.hpp"
59 #include "utilities/macros.hpp"
60
61 // JvmtiTagHashmapEntry
62 //
63 // Each entry encapsulates a reference to the tagged object
64 // and the tag value. In addition an entry includes a next pointer which
65 // is used to chain entries together.
66
67 class JvmtiTagHashmapEntry : public CHeapObj<mtInternal> {
68 private:
69 friend class JvmtiTagMap;
70
71 oop _object; // tagged object
72 jlong _tag; // the tag
73 JvmtiTagHashmapEntry* _next; // next on the list
74
75 inline void init(oop object, jlong tag) {
76 _object = object;
77 _tag = tag;
78 _next = NULL;
79 }
80
81 // constructor
82 JvmtiTagHashmapEntry(oop object, jlong tag) { init(object, tag); }
83
84 public:
85
86 // accessor methods
87 inline oop* object_addr() { return &_object; }
88 inline oop object() { return RootAccess<ON_PHANTOM_OOP_REF>::oop_load(object_addr()); }
89 // Peek at the object without keeping it alive. The returned object must be
90 // kept alive using a normal access if it leaks out of a thread transition from VM.
91 inline oop object_peek() {
92 return RootAccess<ON_PHANTOM_OOP_REF | AS_NO_KEEPALIVE>::oop_load(object_addr());
93 }
94 inline jlong tag() const { return _tag; }
95
96 inline void set_tag(jlong tag) {
97 assert(tag != 0, "can't be zero");
98 _tag = tag;
99 }
100
101 inline bool equals(oop object) {
102 return object == object_peek();
103 }
104
105 inline JvmtiTagHashmapEntry* next() const { return _next; }
106 inline void set_next(JvmtiTagHashmapEntry* next) { _next = next; }
107 };
108
109
110 // JvmtiTagHashmap
111 //
112 // A hashmap is essentially a table of pointers to entries. Entries
113 // are hashed to a location, or position in the table, and then
114 // chained from that location. The "key" for hashing is address of
115 // the object, or oop. The "value" is the tag value.
116 //
117 // A hashmap maintains a count of the number entries in the hashmap
118 // and resizes if the number of entries exceeds a given threshold.
119 // The threshold is specified as a percentage of the size - for
120 // example a threshold of 0.75 will trigger the hashmap to resize
121 // if the number of entries is >75% of table size.
122 //
123 // A hashmap provides functions for adding, removing, and finding
124 // entries. It also provides a function to iterate over all entries
125 // in the hashmap.
126
127 class JvmtiTagHashmap : public CHeapObj<mtInternal> {
128 private:
129 friend class JvmtiTagMap;
130
131 enum {
132 small_trace_threshold = 10000, // threshold for tracing
133 medium_trace_threshold = 100000,
134 large_trace_threshold = 1000000,
135 initial_trace_threshold = small_trace_threshold
136 };
137
138 static int _sizes[]; // array of possible hashmap sizes
139 int _size; // actual size of the table
140 int _size_index; // index into size table
141
142 int _entry_count; // number of entries in the hashmap
143
144 float _load_factor; // load factor as a % of the size
145 int _resize_threshold; // computed threshold to trigger resizing.
146 bool _resizing_enabled; // indicates if hashmap can resize
147
148 int _trace_threshold; // threshold for trace messages
149
150 JvmtiTagHashmapEntry** _table; // the table of entries.
151
152 // private accessors
153 int resize_threshold() const { return _resize_threshold; }
154 int trace_threshold() const { return _trace_threshold; }
155
156 // initialize the hashmap
157 void init(int size_index=0, float load_factor=4.0f) {
158 int initial_size = _sizes[size_index];
159 _size_index = size_index;
160 _size = initial_size;
161 _entry_count = 0;
162 _trace_threshold = initial_trace_threshold;
163 _load_factor = load_factor;
164 _resize_threshold = (int)(_load_factor * _size);
165 _resizing_enabled = true;
166 size_t s = initial_size * sizeof(JvmtiTagHashmapEntry*);
167 _table = (JvmtiTagHashmapEntry**)os::malloc(s, mtInternal);
168 if (_table == NULL) {
169 vm_exit_out_of_memory(s, OOM_MALLOC_ERROR,
170 "unable to allocate initial hashtable for jvmti object tags");
171 }
172 for (int i=0; i<initial_size; i++) {
173 _table[i] = NULL;
174 }
175 }
176
177 // hash a given key (oop) with the specified size
178 static unsigned int hash(oop key, int size) {
179 // shift right to get better distribution (as these bits will be zero
180 // with aligned addresses)
181 unsigned int addr = (unsigned int)(cast_from_oop<intptr_t>(key));
182 #ifdef _LP64
183 return (addr >> 3) % size;
184 #else
185 return (addr >> 2) % size;
186 #endif
187 }
188
189 // hash a given key (oop)
190 unsigned int hash(oop key) {
191 return hash(key, _size);
192 }
193
194 // resize the hashmap - allocates a large table and re-hashes
195 // all entries into the new table.
196 void resize() {
197 int new_size_index = _size_index+1;
198 int new_size = _sizes[new_size_index];
199 if (new_size < 0) {
200 // hashmap already at maximum capacity
201 return;
202 }
203
204 // allocate new table
205 size_t s = new_size * sizeof(JvmtiTagHashmapEntry*);
206 JvmtiTagHashmapEntry** new_table = (JvmtiTagHashmapEntry**)os::malloc(s, mtInternal);
207 if (new_table == NULL) {
208 warning("unable to allocate larger hashtable for jvmti object tags");
209 set_resizing_enabled(false);
210 return;
211 }
212
213 // initialize new table
214 int i;
215 for (i=0; i<new_size; i++) {
216 new_table[i] = NULL;
217 }
218
219 // rehash all entries into the new table
220 for (i=0; i<_size; i++) {
221 JvmtiTagHashmapEntry* entry = _table[i];
222 while (entry != NULL) {
223 JvmtiTagHashmapEntry* next = entry->next();
224 oop key = entry->object_peek();
225 assert(key != NULL, "jni weak reference cleared!!");
226 unsigned int h = hash(key, new_size);
227 JvmtiTagHashmapEntry* anchor = new_table[h];
228 if (anchor == NULL) {
229 new_table[h] = entry;
230 entry->set_next(NULL);
231 } else {
232 entry->set_next(anchor);
233 new_table[h] = entry;
234 }
235 entry = next;
236 }
237 }
238
239 // free old table and update settings.
240 os::free((void*)_table);
241 _table = new_table;
242 _size_index = new_size_index;
243 _size = new_size;
244
245 // compute new resize threshold
246 _resize_threshold = (int)(_load_factor * _size);
247 }
248
249
250 // internal remove function - remove an entry at a given position in the
251 // table.
252 inline void remove(JvmtiTagHashmapEntry* prev, int pos, JvmtiTagHashmapEntry* entry) {
253 assert(pos >= 0 && pos < _size, "out of range");
254 if (prev == NULL) {
255 _table[pos] = entry->next();
256 } else {
257 prev->set_next(entry->next());
258 }
259 assert(_entry_count > 0, "checking");
260 _entry_count--;
261 }
262
263 // resizing switch
264 bool is_resizing_enabled() const { return _resizing_enabled; }
265 void set_resizing_enabled(bool enable) { _resizing_enabled = enable; }
266
267 // debugging
268 void print_memory_usage();
269 void compute_next_trace_threshold();
270
271 public:
272
273 // create a JvmtiTagHashmap of a preferred size and optionally a load factor.
274 // The preferred size is rounded down to an actual size.
275 JvmtiTagHashmap(int size, float load_factor=0.0f) {
276 int i=0;
277 while (_sizes[i] < size) {
278 if (_sizes[i] < 0) {
279 assert(i > 0, "sanity check");
280 i--;
281 break;
282 }
283 i++;
284 }
285
286 // if a load factor is specified then use it, otherwise use default
287 if (load_factor > 0.01f) {
288 init(i, load_factor);
289 } else {
290 init(i);
291 }
292 }
293
294 // create a JvmtiTagHashmap with default settings
295 JvmtiTagHashmap() {
296 init();
297 }
298
299 // release table when JvmtiTagHashmap destroyed
300 ~JvmtiTagHashmap() {
301 if (_table != NULL) {
302 os::free((void*)_table);
303 _table = NULL;
304 }
305 }
306
307 // accessors
308 int size() const { return _size; }
309 JvmtiTagHashmapEntry** table() const { return _table; }
310 int entry_count() const { return _entry_count; }
311
312 // find an entry in the hashmap, returns NULL if not found.
313 inline JvmtiTagHashmapEntry* find(oop key) {
314 unsigned int h = hash(key);
315 JvmtiTagHashmapEntry* entry = _table[h];
316 while (entry != NULL) {
317 if (entry->equals(key)) {
318 return entry;
319 }
320 entry = entry->next();
321 }
322 return NULL;
323 }
324
325
326 // add a new entry to hashmap
327 inline void add(oop key, JvmtiTagHashmapEntry* entry) {
328 assert(key != NULL, "checking");
329 assert(find(key) == NULL, "duplicate detected");
330 unsigned int h = hash(key);
331 JvmtiTagHashmapEntry* anchor = _table[h];
332 if (anchor == NULL) {
333 _table[h] = entry;
334 entry->set_next(NULL);
335 } else {
336 entry->set_next(anchor);
337 _table[h] = entry;
338 }
339
340 _entry_count++;
341 if (log_is_enabled(Debug, jvmti, objecttagging) && entry_count() >= trace_threshold()) {
342 print_memory_usage();
343 compute_next_trace_threshold();
344 }
345
346 // if the number of entries exceed the threshold then resize
347 if (entry_count() > resize_threshold() && is_resizing_enabled()) {
348 resize();
349 }
350 }
351
352 // remove an entry with the given key.
353 inline JvmtiTagHashmapEntry* remove(oop key) {
354 unsigned int h = hash(key);
355 JvmtiTagHashmapEntry* entry = _table[h];
356 JvmtiTagHashmapEntry* prev = NULL;
357 while (entry != NULL) {
358 if (entry->equals(key)) {
359 break;
360 }
361 prev = entry;
362 entry = entry->next();
363 }
364 if (entry != NULL) {
365 remove(prev, h, entry);
366 }
367 return entry;
368 }
369
370 // iterate over all entries in the hashmap
371 void entry_iterate(JvmtiTagHashmapEntryClosure* closure);
372 };
373
374 // possible hashmap sizes - odd primes that roughly double in size.
375 // To avoid excessive resizing the odd primes from 4801-76831 and
376 // 76831-307261 have been removed. The list must be terminated by -1.
377 int JvmtiTagHashmap::_sizes[] = { 4801, 76831, 307261, 614563, 1228891,
378 2457733, 4915219, 9830479, 19660831, 39321619, 78643219, -1 };
379
380
381 // A supporting class for iterating over all entries in Hashmap
382 class JvmtiTagHashmapEntryClosure {
383 public:
384 virtual void do_entry(JvmtiTagHashmapEntry* entry) = 0;
385 };
386
387
388 // iterate over all entries in the hashmap
389 void JvmtiTagHashmap::entry_iterate(JvmtiTagHashmapEntryClosure* closure) {
390 for (int i=0; i<_size; i++) {
391 JvmtiTagHashmapEntry* entry = _table[i];
392 JvmtiTagHashmapEntry* prev = NULL;
393 while (entry != NULL) {
394 // obtain the next entry before invoking do_entry - this is
395 // necessary because do_entry may remove the entry from the
396 // hashmap.
397 JvmtiTagHashmapEntry* next = entry->next();
398 closure->do_entry(entry);
399 entry = next;
400 }
401 }
402 }
403
404 // debugging
405 void JvmtiTagHashmap::print_memory_usage() {
406 intptr_t p = (intptr_t)this;
407 tty->print("[JvmtiTagHashmap @ " INTPTR_FORMAT, p);
408
409 // table + entries in KB
410 int hashmap_usage = (size()*sizeof(JvmtiTagHashmapEntry*) +
411 entry_count()*sizeof(JvmtiTagHashmapEntry))/K;
412
413 int weak_globals_usage = (int)(JNIHandles::weak_global_handle_memory_usage()/K);
414 tty->print_cr(", %d entries (%d KB) <JNI weak globals: %d KB>]",
415 entry_count(), hashmap_usage, weak_globals_usage);
416 }
417
418 // compute threshold for the next trace message
419 void JvmtiTagHashmap::compute_next_trace_threshold() {
420 _trace_threshold = entry_count();
421 if (trace_threshold() < medium_trace_threshold) {
422 _trace_threshold += small_trace_threshold;
423 } else {
424 if (trace_threshold() < large_trace_threshold) {
425 _trace_threshold += medium_trace_threshold;
426 } else {
427 _trace_threshold += large_trace_threshold;
428 }
429 }
430 }
431
432 // create a JvmtiTagMap
433 JvmtiTagMap::JvmtiTagMap(JvmtiEnv* env) :
434 _env(env),
435 _lock(Mutex::nonleaf+2, "JvmtiTagMap._lock", false),
436 _free_entries(NULL),
437 _free_entries_count(0)
438 {
439 assert(JvmtiThreadState_lock->is_locked(), "sanity check");
440 assert(((JvmtiEnvBase *)env)->tag_map() == NULL, "tag map already exists for environment");
441
442 _hashmap = new JvmtiTagHashmap();
443
444 // finally add us to the environment
445 ((JvmtiEnvBase *)env)->set_tag_map(this);
446 }
447
448
449 // destroy a JvmtiTagMap
450 JvmtiTagMap::~JvmtiTagMap() {
451
452 // no lock acquired as we assume the enclosing environment is
453 // also being destroryed.
454 ((JvmtiEnvBase *)_env)->set_tag_map(NULL);
455
456 JvmtiTagHashmapEntry** table = _hashmap->table();
457 for (int j = 0; j < _hashmap->size(); j++) {
458 JvmtiTagHashmapEntry* entry = table[j];
459 while (entry != NULL) {
460 JvmtiTagHashmapEntry* next = entry->next();
461 delete entry;
462 entry = next;
463 }
464 }
465
466 // finally destroy the hashmap
467 delete _hashmap;
468 _hashmap = NULL;
469
470 // remove any entries on the free list
471 JvmtiTagHashmapEntry* entry = _free_entries;
472 while (entry != NULL) {
473 JvmtiTagHashmapEntry* next = entry->next();
474 delete entry;
475 entry = next;
476 }
477 _free_entries = NULL;
478 }
479
480 // create a hashmap entry
481 // - if there's an entry on the (per-environment) free list then this
482 // is returned. Otherwise an new entry is allocated.
483 JvmtiTagHashmapEntry* JvmtiTagMap::create_entry(oop ref, jlong tag) {
484 assert(Thread::current()->is_VM_thread() || is_locked(), "checking");
485 JvmtiTagHashmapEntry* entry;
486 if (_free_entries == NULL) {
487 entry = new JvmtiTagHashmapEntry(ref, tag);
488 } else {
489 assert(_free_entries_count > 0, "mismatched _free_entries_count");
490 _free_entries_count--;
491 entry = _free_entries;
492 _free_entries = entry->next();
493 entry->init(ref, tag);
494 }
495 return entry;
496 }
497
498 // destroy an entry by returning it to the free list
499 void JvmtiTagMap::destroy_entry(JvmtiTagHashmapEntry* entry) {
500 assert(SafepointSynchronize::is_at_safepoint() || is_locked(), "checking");
501 // limit the size of the free list
502 if (_free_entries_count >= max_free_entries) {
503 delete entry;
504 } else {
505 entry->set_next(_free_entries);
506 _free_entries = entry;
507 _free_entries_count++;
508 }
509 }
510
511 // returns the tag map for the given environments. If the tag map
512 // doesn't exist then it is created.
513 JvmtiTagMap* JvmtiTagMap::tag_map_for(JvmtiEnv* env) {
514 JvmtiTagMap* tag_map = ((JvmtiEnvBase*)env)->tag_map();
515 if (tag_map == NULL) {
516 MutexLocker mu(JvmtiThreadState_lock);
517 tag_map = ((JvmtiEnvBase*)env)->tag_map();
518 if (tag_map == NULL) {
519 tag_map = new JvmtiTagMap(env);
520 }
521 } else {
522 CHECK_UNHANDLED_OOPS_ONLY(Thread::current()->clear_unhandled_oops());
523 }
524 return tag_map;
525 }
526
527 // iterate over all entries in the tag map.
528 void JvmtiTagMap::entry_iterate(JvmtiTagHashmapEntryClosure* closure) {
529 hashmap()->entry_iterate(closure);
530 }
531
532 // returns true if the hashmaps are empty
533 bool JvmtiTagMap::is_empty() {
534 assert(SafepointSynchronize::is_at_safepoint() || is_locked(), "checking");
535 return hashmap()->entry_count() == 0;
536 }
537
538
539 // Return the tag value for an object, or 0 if the object is
540 // not tagged
541 //
542 static inline jlong tag_for(JvmtiTagMap* tag_map, oop o) {
543 JvmtiTagHashmapEntry* entry = tag_map->hashmap()->find(o);
544 if (entry == NULL) {
545 return 0;
546 } else {
547 return entry->tag();
548 }
549 }
550
551
552 // A CallbackWrapper is a support class for querying and tagging an object
553 // around a callback to a profiler. The constructor does pre-callback
554 // work to get the tag value, klass tag value, ... and the destructor
555 // does the post-callback work of tagging or untagging the object.
556 //
557 // {
558 // CallbackWrapper wrapper(tag_map, o);
559 //
560 // (*callback)(wrapper.klass_tag(), wrapper.obj_size(), wrapper.obj_tag_p(), ...)
561 //
562 // } // wrapper goes out of scope here which results in the destructor
563 // checking to see if the object has been tagged, untagged, or the
564 // tag value has changed.
565 //
566 class CallbackWrapper : public StackObj {
567 private:
568 JvmtiTagMap* _tag_map;
569 JvmtiTagHashmap* _hashmap;
570 JvmtiTagHashmapEntry* _entry;
571 oop _o;
572 jlong _obj_size;
573 jlong _obj_tag;
574 jlong _klass_tag;
575
576 protected:
577 JvmtiTagMap* tag_map() const { return _tag_map; }
578
579 // invoked post-callback to tag, untag, or update the tag of an object
580 void inline post_callback_tag_update(oop o, JvmtiTagHashmap* hashmap,
581 JvmtiTagHashmapEntry* entry, jlong obj_tag);
582 public:
583 CallbackWrapper(JvmtiTagMap* tag_map, oop o) {
584 assert(Thread::current()->is_VM_thread() || tag_map->is_locked(),
585 "MT unsafe or must be VM thread");
586
587 // object to tag
588 _o = o;
589
590 // object size
591 _obj_size = (jlong)_o->size() * wordSize;
592
593 // record the context
594 _tag_map = tag_map;
595 _hashmap = tag_map->hashmap();
596 _entry = _hashmap->find(_o);
597
598 // get object tag
599 _obj_tag = (_entry == NULL) ? 0 : _entry->tag();
600
601 // get the class and the class's tag value
602 assert(SystemDictionary::Class_klass()->is_mirror_instance_klass(), "Is not?");
603
604 _klass_tag = tag_for(tag_map, _o->klass()->java_mirror());
605 }
606
607 ~CallbackWrapper() {
608 post_callback_tag_update(_o, _hashmap, _entry, _obj_tag);
609 }
610
611 inline jlong* obj_tag_p() { return &_obj_tag; }
612 inline jlong obj_size() const { return _obj_size; }
613 inline jlong obj_tag() const { return _obj_tag; }
614 inline jlong klass_tag() const { return _klass_tag; }
615 };
616
617
618
619 // callback post-callback to tag, untag, or update the tag of an object
620 void inline CallbackWrapper::post_callback_tag_update(oop o,
621 JvmtiTagHashmap* hashmap,
622 JvmtiTagHashmapEntry* entry,
623 jlong obj_tag) {
624 if (entry == NULL) {
625 if (obj_tag != 0) {
626 // callback has tagged the object
627 assert(Thread::current()->is_VM_thread(), "must be VMThread");
628 entry = tag_map()->create_entry(o, obj_tag);
629 hashmap->add(o, entry);
630 }
631 } else {
632 // object was previously tagged - the callback may have untagged
633 // the object or changed the tag value
634 if (obj_tag == 0) {
635
636 JvmtiTagHashmapEntry* entry_removed = hashmap->remove(o);
637 assert(entry_removed == entry, "checking");
638 tag_map()->destroy_entry(entry);
639
640 } else {
641 if (obj_tag != entry->tag()) {
642 entry->set_tag(obj_tag);
643 }
644 }
645 }
646 }
647
648 // An extended CallbackWrapper used when reporting an object reference
649 // to the agent.
650 //
651 // {
652 // TwoOopCallbackWrapper wrapper(tag_map, referrer, o);
653 //
654 // (*callback)(wrapper.klass_tag(),
655 // wrapper.obj_size(),
656 // wrapper.obj_tag_p()
657 // wrapper.referrer_tag_p(), ...)
658 //
659 // } // wrapper goes out of scope here which results in the destructor
660 // checking to see if the referrer object has been tagged, untagged,
661 // or the tag value has changed.
662 //
663 class TwoOopCallbackWrapper : public CallbackWrapper {
664 private:
665 bool _is_reference_to_self;
666 JvmtiTagHashmap* _referrer_hashmap;
667 JvmtiTagHashmapEntry* _referrer_entry;
668 oop _referrer;
669 jlong _referrer_obj_tag;
670 jlong _referrer_klass_tag;
671 jlong* _referrer_tag_p;
672
673 bool is_reference_to_self() const { return _is_reference_to_self; }
674
675 public:
676 TwoOopCallbackWrapper(JvmtiTagMap* tag_map, oop referrer, oop o) :
677 CallbackWrapper(tag_map, o)
678 {
679 // self reference needs to be handled in a special way
680 _is_reference_to_self = (referrer == o);
681
682 if (_is_reference_to_self) {
683 _referrer_klass_tag = klass_tag();
684 _referrer_tag_p = obj_tag_p();
685 } else {
686 _referrer = referrer;
687 // record the context
688 _referrer_hashmap = tag_map->hashmap();
689 _referrer_entry = _referrer_hashmap->find(_referrer);
690
691 // get object tag
692 _referrer_obj_tag = (_referrer_entry == NULL) ? 0 : _referrer_entry->tag();
693 _referrer_tag_p = &_referrer_obj_tag;
694
695 // get referrer class tag.
696 _referrer_klass_tag = tag_for(tag_map, _referrer->klass()->java_mirror());
697 }
698 }
699
700 ~TwoOopCallbackWrapper() {
701 if (!is_reference_to_self()){
702 post_callback_tag_update(_referrer,
703 _referrer_hashmap,
704 _referrer_entry,
705 _referrer_obj_tag);
706 }
707 }
708
709 // address of referrer tag
710 // (for a self reference this will return the same thing as obj_tag_p())
711 inline jlong* referrer_tag_p() { return _referrer_tag_p; }
712
713 // referrer's class tag
714 inline jlong referrer_klass_tag() { return _referrer_klass_tag; }
715 };
716
717 // tag an object
718 //
719 // This function is performance critical. If many threads attempt to tag objects
720 // around the same time then it's possible that the Mutex associated with the
721 // tag map will be a hot lock.
722 void JvmtiTagMap::set_tag(jobject object, jlong tag) {
723 MutexLocker ml(lock());
724
725 // resolve the object
726 oop o = JNIHandles::resolve_non_null(object);
727
728 // see if the object is already tagged
729 JvmtiTagHashmap* hashmap = _hashmap;
730 JvmtiTagHashmapEntry* entry = hashmap->find(o);
731
732 // if the object is not already tagged then we tag it
733 if (entry == NULL) {
734 if (tag != 0) {
735 entry = create_entry(o, tag);
736 hashmap->add(o, entry);
737 } else {
738 // no-op
739 }
740 } else {
741 // if the object is already tagged then we either update
742 // the tag (if a new tag value has been provided)
743 // or remove the object if the new tag value is 0.
744 if (tag == 0) {
745 hashmap->remove(o);
746 destroy_entry(entry);
747 } else {
748 entry->set_tag(tag);
749 }
750 }
751 }
752
753 // get the tag for an object
754 jlong JvmtiTagMap::get_tag(jobject object) {
755 MutexLocker ml(lock());
756
757 // resolve the object
758 oop o = JNIHandles::resolve_non_null(object);
759
760 return tag_for(this, o);
761 }
762
763
764 // Helper class used to describe the static or instance fields of a class.
765 // For each field it holds the field index (as defined by the JVMTI specification),
766 // the field type, and the offset.
767
768 class ClassFieldDescriptor: public CHeapObj<mtInternal> {
769 private:
770 int _field_index;
771 int _field_offset;
772 char _field_type;
773 public:
774 ClassFieldDescriptor(int index, char type, int offset) :
775 _field_index(index), _field_type(type), _field_offset(offset) {
776 }
777 int field_index() const { return _field_index; }
778 char field_type() const { return _field_type; }
779 int field_offset() const { return _field_offset; }
780 };
781
782 class ClassFieldMap: public CHeapObj<mtInternal> {
783 private:
784 enum {
785 initial_field_count = 5
786 };
787
788 // list of field descriptors
789 GrowableArray<ClassFieldDescriptor*>* _fields;
790
791 // constructor
792 ClassFieldMap();
793
794 // add a field
795 void add(int index, char type, int offset);
796
797 // returns the field count for the given class
798 static int compute_field_count(InstanceKlass* ik);
799
800 public:
801 ~ClassFieldMap();
802
803 // access
804 int field_count() { return _fields->length(); }
805 ClassFieldDescriptor* field_at(int i) { return _fields->at(i); }
806
807 // functions to create maps of static or instance fields
808 static ClassFieldMap* create_map_of_static_fields(Klass* k);
809 static ClassFieldMap* create_map_of_instance_fields(oop obj);
810 };
811
812 ClassFieldMap::ClassFieldMap() {
813 _fields = new (ResourceObj::C_HEAP, mtInternal)
814 GrowableArray<ClassFieldDescriptor*>(initial_field_count, true);
815 }
816
817 ClassFieldMap::~ClassFieldMap() {
818 for (int i=0; i<_fields->length(); i++) {
819 delete _fields->at(i);
820 }
821 delete _fields;
822 }
823
824 void ClassFieldMap::add(int index, char type, int offset) {
825 ClassFieldDescriptor* field = new ClassFieldDescriptor(index, type, offset);
826 _fields->append(field);
827 }
828
829 // Returns a heap allocated ClassFieldMap to describe the static fields
830 // of the given class.
831 //
832 ClassFieldMap* ClassFieldMap::create_map_of_static_fields(Klass* k) {
833 HandleMark hm;
834 InstanceKlass* ik = InstanceKlass::cast(k);
835
836 // create the field map
837 ClassFieldMap* field_map = new ClassFieldMap();
838
839 FilteredFieldStream f(ik, false, false);
840 int max_field_index = f.field_count()-1;
841
842 int index = 0;
843 for (FilteredFieldStream fld(ik, true, true); !fld.eos(); fld.next(), index++) {
844 // ignore instance fields
845 if (!fld.access_flags().is_static()) {
846 continue;
847 }
848 field_map->add(max_field_index - index, fld.signature()->byte_at(0), fld.offset());
849 }
850 return field_map;
851 }
852
853 // Returns a heap allocated ClassFieldMap to describe the instance fields
854 // of the given class. All instance fields are included (this means public
855 // and private fields declared in superclasses and superinterfaces too).
856 //
857 ClassFieldMap* ClassFieldMap::create_map_of_instance_fields(oop obj) {
858 HandleMark hm;
859 InstanceKlass* ik = InstanceKlass::cast(obj->klass());
860
861 // create the field map
862 ClassFieldMap* field_map = new ClassFieldMap();
863
864 FilteredFieldStream f(ik, false, false);
865
866 int max_field_index = f.field_count()-1;
867
868 int index = 0;
869 for (FilteredFieldStream fld(ik, false, false); !fld.eos(); fld.next(), index++) {
870 // ignore static fields
871 if (fld.access_flags().is_static()) {
872 continue;
873 }
874 field_map->add(max_field_index - index, fld.signature()->byte_at(0), fld.offset());
875 }
876
877 return field_map;
878 }
879
880 // Helper class used to cache a ClassFileMap for the instance fields of
881 // a cache. A JvmtiCachedClassFieldMap can be cached by an InstanceKlass during
882 // heap iteration and avoid creating a field map for each object in the heap
883 // (only need to create the map when the first instance of a class is encountered).
884 //
885 class JvmtiCachedClassFieldMap : public CHeapObj<mtInternal> {
886 private:
887 enum {
888 initial_class_count = 200
889 };
890 ClassFieldMap* _field_map;
891
892 ClassFieldMap* field_map() const { return _field_map; }
893
894 JvmtiCachedClassFieldMap(ClassFieldMap* field_map);
895 ~JvmtiCachedClassFieldMap();
896
897 static GrowableArray<InstanceKlass*>* _class_list;
898 static void add_to_class_list(InstanceKlass* ik);
899
900 public:
901 // returns the field map for a given object (returning map cached
902 // by InstanceKlass if possible
903 static ClassFieldMap* get_map_of_instance_fields(oop obj);
904
905 // removes the field map from all instanceKlasses - should be
906 // called before VM operation completes
907 static void clear_cache();
908
909 // returns the number of ClassFieldMap cached by instanceKlasses
910 static int cached_field_map_count();
911 };
912
913 GrowableArray<InstanceKlass*>* JvmtiCachedClassFieldMap::_class_list;
914
915 JvmtiCachedClassFieldMap::JvmtiCachedClassFieldMap(ClassFieldMap* field_map) {
916 _field_map = field_map;
917 }
918
919 JvmtiCachedClassFieldMap::~JvmtiCachedClassFieldMap() {
920 if (_field_map != NULL) {
921 delete _field_map;
922 }
923 }
924
925 // Marker class to ensure that the class file map cache is only used in a defined
926 // scope.
927 class ClassFieldMapCacheMark : public StackObj {
928 private:
929 static bool _is_active;
930 public:
931 ClassFieldMapCacheMark() {
932 assert(Thread::current()->is_VM_thread(), "must be VMThread");
933 assert(JvmtiCachedClassFieldMap::cached_field_map_count() == 0, "cache not empty");
934 assert(!_is_active, "ClassFieldMapCacheMark cannot be nested");
935 _is_active = true;
936 }
937 ~ClassFieldMapCacheMark() {
938 JvmtiCachedClassFieldMap::clear_cache();
939 _is_active = false;
940 }
941 static bool is_active() { return _is_active; }
942 };
943
944 bool ClassFieldMapCacheMark::_is_active;
945
946
947 // record that the given InstanceKlass is caching a field map
948 void JvmtiCachedClassFieldMap::add_to_class_list(InstanceKlass* ik) {
949 if (_class_list == NULL) {
950 _class_list = new (ResourceObj::C_HEAP, mtInternal)
951 GrowableArray<InstanceKlass*>(initial_class_count, true);
952 }
953 _class_list->push(ik);
954 }
955
956 // returns the instance field map for the given object
957 // (returns field map cached by the InstanceKlass if possible)
958 ClassFieldMap* JvmtiCachedClassFieldMap::get_map_of_instance_fields(oop obj) {
959 assert(Thread::current()->is_VM_thread(), "must be VMThread");
960 assert(ClassFieldMapCacheMark::is_active(), "ClassFieldMapCacheMark not active");
961
962 Klass* k = obj->klass();
963 InstanceKlass* ik = InstanceKlass::cast(k);
964
965 // return cached map if possible
966 JvmtiCachedClassFieldMap* cached_map = ik->jvmti_cached_class_field_map();
967 if (cached_map != NULL) {
968 assert(cached_map->field_map() != NULL, "missing field list");
969 return cached_map->field_map();
970 } else {
971 ClassFieldMap* field_map = ClassFieldMap::create_map_of_instance_fields(obj);
972 cached_map = new JvmtiCachedClassFieldMap(field_map);
973 ik->set_jvmti_cached_class_field_map(cached_map);
974 add_to_class_list(ik);
975 return field_map;
976 }
977 }
978
979 // remove the fields maps cached from all instanceKlasses
980 void JvmtiCachedClassFieldMap::clear_cache() {
981 assert(Thread::current()->is_VM_thread(), "must be VMThread");
982 if (_class_list != NULL) {
983 for (int i = 0; i < _class_list->length(); i++) {
984 InstanceKlass* ik = _class_list->at(i);
985 JvmtiCachedClassFieldMap* cached_map = ik->jvmti_cached_class_field_map();
986 assert(cached_map != NULL, "should not be NULL");
987 ik->set_jvmti_cached_class_field_map(NULL);
988 delete cached_map; // deletes the encapsulated field map
989 }
990 delete _class_list;
991 _class_list = NULL;
992 }
993 }
994
995 // returns the number of ClassFieldMap cached by instanceKlasses
996 int JvmtiCachedClassFieldMap::cached_field_map_count() {
997 return (_class_list == NULL) ? 0 : _class_list->length();
998 }
999
1000 // helper function to indicate if an object is filtered by its tag or class tag
1001 static inline bool is_filtered_by_heap_filter(jlong obj_tag,
1002 jlong klass_tag,
1003 int heap_filter) {
1004 // apply the heap filter
1005 if (obj_tag != 0) {
1006 // filter out tagged objects
1007 if (heap_filter & JVMTI_HEAP_FILTER_TAGGED) return true;
1008 } else {
1009 // filter out untagged objects
1010 if (heap_filter & JVMTI_HEAP_FILTER_UNTAGGED) return true;
1011 }
1012 if (klass_tag != 0) {
1013 // filter out objects with tagged classes
1014 if (heap_filter & JVMTI_HEAP_FILTER_CLASS_TAGGED) return true;
1015 } else {
1016 // filter out objects with untagged classes.
1017 if (heap_filter & JVMTI_HEAP_FILTER_CLASS_UNTAGGED) return true;
1018 }
1019 return false;
1020 }
1021
1022 // helper function to indicate if an object is filtered by a klass filter
1023 static inline bool is_filtered_by_klass_filter(oop obj, Klass* klass_filter) {
1024 if (klass_filter != NULL) {
1025 if (obj->klass() != klass_filter) {
1026 return true;
1027 }
1028 }
1029 return false;
1030 }
1031
1032 // helper function to tell if a field is a primitive field or not
1033 static inline bool is_primitive_field_type(char type) {
1034 return (type != 'L' && type != '[');
1035 }
1036
1037 // helper function to copy the value from location addr to jvalue.
1038 static inline void copy_to_jvalue(jvalue *v, address addr, jvmtiPrimitiveType value_type) {
1039 switch (value_type) {
1040 case JVMTI_PRIMITIVE_TYPE_BOOLEAN : { v->z = *(jboolean*)addr; break; }
1041 case JVMTI_PRIMITIVE_TYPE_BYTE : { v->b = *(jbyte*)addr; break; }
1042 case JVMTI_PRIMITIVE_TYPE_CHAR : { v->c = *(jchar*)addr; break; }
1043 case JVMTI_PRIMITIVE_TYPE_SHORT : { v->s = *(jshort*)addr; break; }
1044 case JVMTI_PRIMITIVE_TYPE_INT : { v->i = *(jint*)addr; break; }
1045 case JVMTI_PRIMITIVE_TYPE_LONG : { v->j = *(jlong*)addr; break; }
1046 case JVMTI_PRIMITIVE_TYPE_FLOAT : { v->f = *(jfloat*)addr; break; }
1047 case JVMTI_PRIMITIVE_TYPE_DOUBLE : { v->d = *(jdouble*)addr; break; }
1048 default: ShouldNotReachHere();
1049 }
1050 }
1051
1052 // helper function to invoke string primitive value callback
1053 // returns visit control flags
1054 static jint invoke_string_value_callback(jvmtiStringPrimitiveValueCallback cb,
1055 CallbackWrapper* wrapper,
1056 oop str,
1057 void* user_data)
1058 {
1059 assert(str->klass() == SystemDictionary::String_klass(), "not a string");
1060
1061 typeArrayOop s_value = java_lang_String::value(str);
1062
1063 // JDK-6584008: the value field may be null if a String instance is
1064 // partially constructed.
1065 if (s_value == NULL) {
1066 return 0;
1067 }
1068 // get the string value and length
1069 // (string value may be offset from the base)
1070 int s_len = java_lang_String::length(str);
1071 bool is_latin1 = java_lang_String::is_latin1(str);
1072 jchar* value;
1073 if (s_len > 0) {
1074 if (!is_latin1) {
1075 value = s_value->char_at_addr(0);
1076 } else {
1077 // Inflate latin1 encoded string to UTF16
1078 jchar* buf = NEW_C_HEAP_ARRAY(jchar, s_len, mtInternal);
1079 for (int i = 0; i < s_len; i++) {
1080 buf[i] = ((jchar) s_value->byte_at(i)) & 0xff;
1081 }
1082 value = &buf[0];
1083 }
1084 } else {
1085 // Don't use char_at_addr(0) if length is 0
1086 value = (jchar*) s_value->base(T_CHAR);
1087 }
1088
1089 // invoke the callback
1090 jint res = (*cb)(wrapper->klass_tag(),
1091 wrapper->obj_size(),
1092 wrapper->obj_tag_p(),
1093 value,
1094 (jint)s_len,
1095 user_data);
1096
1097 if (is_latin1 && s_len > 0) {
1098 FREE_C_HEAP_ARRAY(jchar, value);
1099 }
1100 return res;
1101 }
1102
1103 // helper function to invoke string primitive value callback
1104 // returns visit control flags
1105 static jint invoke_array_primitive_value_callback(jvmtiArrayPrimitiveValueCallback cb,
1106 CallbackWrapper* wrapper,
1107 oop obj,
1108 void* user_data)
1109 {
1110 assert(obj->is_typeArray(), "not a primitive array");
1111
1112 // get base address of first element
1113 typeArrayOop array = typeArrayOop(obj);
1114 BasicType type = TypeArrayKlass::cast(array->klass())->element_type();
1115 void* elements = array->base(type);
1116
1117 // jvmtiPrimitiveType is defined so this mapping is always correct
1118 jvmtiPrimitiveType elem_type = (jvmtiPrimitiveType)type2char(type);
1119
1120 return (*cb)(wrapper->klass_tag(),
1121 wrapper->obj_size(),
1122 wrapper->obj_tag_p(),
1123 (jint)array->length(),
1124 elem_type,
1125 elements,
1126 user_data);
1127 }
1128
1129 // helper function to invoke the primitive field callback for all static fields
1130 // of a given class
1131 static jint invoke_primitive_field_callback_for_static_fields
1132 (CallbackWrapper* wrapper,
1133 oop obj,
1134 jvmtiPrimitiveFieldCallback cb,
1135 void* user_data)
1136 {
1137 // for static fields only the index will be set
1138 static jvmtiHeapReferenceInfo reference_info = { 0 };
1139
1140 assert(obj->klass() == SystemDictionary::Class_klass(), "not a class");
1141 if (java_lang_Class::is_primitive(obj)) {
1142 return 0;
1143 }
1144 Klass* klass = java_lang_Class::as_Klass(obj);
1145
1146 // ignore classes for object and type arrays
1147 if (!klass->is_instance_klass()) {
1148 return 0;
1149 }
1150
1151 // ignore classes which aren't linked yet
1152 InstanceKlass* ik = InstanceKlass::cast(klass);
1153 if (!ik->is_linked()) {
1154 return 0;
1155 }
1156
1157 // get the field map
1158 ClassFieldMap* field_map = ClassFieldMap::create_map_of_static_fields(klass);
1159
1160 // invoke the callback for each static primitive field
1161 for (int i=0; i<field_map->field_count(); i++) {
1162 ClassFieldDescriptor* field = field_map->field_at(i);
1163
1164 // ignore non-primitive fields
1165 char type = field->field_type();
1166 if (!is_primitive_field_type(type)) {
1167 continue;
1168 }
1169 // one-to-one mapping
1170 jvmtiPrimitiveType value_type = (jvmtiPrimitiveType)type;
1171
1172 // get offset and field value
1173 int offset = field->field_offset();
1174 address addr = (address)klass->java_mirror() + offset;
1175 jvalue value;
1176 copy_to_jvalue(&value, addr, value_type);
1177
1178 // field index
1179 reference_info.field.index = field->field_index();
1180
1181 // invoke the callback
1182 jint res = (*cb)(JVMTI_HEAP_REFERENCE_STATIC_FIELD,
1183 &reference_info,
1184 wrapper->klass_tag(),
1185 wrapper->obj_tag_p(),
1186 value,
1187 value_type,
1188 user_data);
1189 if (res & JVMTI_VISIT_ABORT) {
1190 delete field_map;
1191 return res;
1192 }
1193 }
1194
1195 delete field_map;
1196 return 0;
1197 }
1198
1199 // helper function to invoke the primitive field callback for all instance fields
1200 // of a given object
1201 static jint invoke_primitive_field_callback_for_instance_fields(
1202 CallbackWrapper* wrapper,
1203 oop obj,
1204 jvmtiPrimitiveFieldCallback cb,
1205 void* user_data)
1206 {
1207 // for instance fields only the index will be set
1208 static jvmtiHeapReferenceInfo reference_info = { 0 };
1209
1210 // get the map of the instance fields
1211 ClassFieldMap* fields = JvmtiCachedClassFieldMap::get_map_of_instance_fields(obj);
1212
1213 // invoke the callback for each instance primitive field
1214 for (int i=0; i<fields->field_count(); i++) {
1215 ClassFieldDescriptor* field = fields->field_at(i);
1216
1217 // ignore non-primitive fields
1218 char type = field->field_type();
1219 if (!is_primitive_field_type(type)) {
1220 continue;
1221 }
1222 // one-to-one mapping
1223 jvmtiPrimitiveType value_type = (jvmtiPrimitiveType)type;
1224
1225 // get offset and field value
1226 int offset = field->field_offset();
1227 address addr = (address)obj + offset;
1228 jvalue value;
1229 copy_to_jvalue(&value, addr, value_type);
1230
1231 // field index
1232 reference_info.field.index = field->field_index();
1233
1234 // invoke the callback
1235 jint res = (*cb)(JVMTI_HEAP_REFERENCE_FIELD,
1236 &reference_info,
1237 wrapper->klass_tag(),
1238 wrapper->obj_tag_p(),
1239 value,
1240 value_type,
1241 user_data);
1242 if (res & JVMTI_VISIT_ABORT) {
1243 return res;
1244 }
1245 }
1246 return 0;
1247 }
1248
1249
1250 // VM operation to iterate over all objects in the heap (both reachable
1251 // and unreachable)
1252 class VM_HeapIterateOperation: public VM_Operation {
1253 private:
1254 ObjectClosure* _blk;
1255 public:
1256 VM_HeapIterateOperation(ObjectClosure* blk) { _blk = blk; }
1257
1258 VMOp_Type type() const { return VMOp_HeapIterateOperation; }
1259 void doit() {
1260 // allows class files maps to be cached during iteration
1261 ClassFieldMapCacheMark cm;
1262
1263 // make sure that heap is parsable (fills TLABs with filler objects)
1264 Universe::heap()->ensure_parsability(false); // no need to retire TLABs
1265
1266 // Verify heap before iteration - if the heap gets corrupted then
1267 // JVMTI's IterateOverHeap will crash.
1268 if (VerifyBeforeIteration) {
1269 Universe::verify();
1270 }
1271
1272 // do the iteration
1273 // If this operation encounters a bad object when using CMS,
1274 // consider using safe_object_iterate() which avoids perm gen
1275 // objects that may contain bad references.
1276 Universe::heap()->object_iterate(_blk);
1277 }
1278
1279 };
1280
1281
1282 // An ObjectClosure used to support the deprecated IterateOverHeap and
1283 // IterateOverInstancesOfClass functions
1284 class IterateOverHeapObjectClosure: public ObjectClosure {
1285 private:
1286 JvmtiTagMap* _tag_map;
1287 Klass* _klass;
1288 jvmtiHeapObjectFilter _object_filter;
1289 jvmtiHeapObjectCallback _heap_object_callback;
1290 const void* _user_data;
1291
1292 // accessors
1293 JvmtiTagMap* tag_map() const { return _tag_map; }
1294 jvmtiHeapObjectFilter object_filter() const { return _object_filter; }
1295 jvmtiHeapObjectCallback object_callback() const { return _heap_object_callback; }
1296 Klass* klass() const { return _klass; }
1297 const void* user_data() const { return _user_data; }
1298
1299 // indicates if iteration has been aborted
1300 bool _iteration_aborted;
1301 bool is_iteration_aborted() const { return _iteration_aborted; }
1302 void set_iteration_aborted(bool aborted) { _iteration_aborted = aborted; }
1303
1304 public:
1305 IterateOverHeapObjectClosure(JvmtiTagMap* tag_map,
1306 Klass* klass,
1307 jvmtiHeapObjectFilter object_filter,
1308 jvmtiHeapObjectCallback heap_object_callback,
1309 const void* user_data) :
1310 _tag_map(tag_map),
1311 _klass(klass),
1312 _object_filter(object_filter),
1313 _heap_object_callback(heap_object_callback),
1314 _user_data(user_data),
1315 _iteration_aborted(false)
1316 {
1317 }
1318
1319 void do_object(oop o);
1320 };
1321
1322 // invoked for each object in the heap
1323 void IterateOverHeapObjectClosure::do_object(oop o) {
1324 // check if iteration has been halted
1325 if (is_iteration_aborted()) return;
1326
1327 // ignore any objects that aren't visible to profiler
1328 if (!ServiceUtil::visible_oop(o)) return;
1329
1330 // instanceof check when filtering by klass
1331 if (klass() != NULL && !o->is_a(klass())) {
1332 return;
1333 }
1334 // prepare for the calllback
1335 CallbackWrapper wrapper(tag_map(), o);
1336
1337 // if the object is tagged and we're only interested in untagged objects
1338 // then don't invoke the callback. Similiarly, if the object is untagged
1339 // and we're only interested in tagged objects we skip the callback.
1340 if (wrapper.obj_tag() != 0) {
1341 if (object_filter() == JVMTI_HEAP_OBJECT_UNTAGGED) return;
1342 } else {
1343 if (object_filter() == JVMTI_HEAP_OBJECT_TAGGED) return;
1344 }
1345
1346 // invoke the agent's callback
1347 jvmtiIterationControl control = (*object_callback())(wrapper.klass_tag(),
1348 wrapper.obj_size(),
1349 wrapper.obj_tag_p(),
1350 (void*)user_data());
1351 if (control == JVMTI_ITERATION_ABORT) {
1352 set_iteration_aborted(true);
1353 }
1354 }
1355
1356 // An ObjectClosure used to support the IterateThroughHeap function
1357 class IterateThroughHeapObjectClosure: public ObjectClosure {
1358 private:
1359 JvmtiTagMap* _tag_map;
1360 Klass* _klass;
1361 int _heap_filter;
1362 const jvmtiHeapCallbacks* _callbacks;
1363 const void* _user_data;
1364
1365 // accessor functions
1366 JvmtiTagMap* tag_map() const { return _tag_map; }
1367 int heap_filter() const { return _heap_filter; }
1368 const jvmtiHeapCallbacks* callbacks() const { return _callbacks; }
1369 Klass* klass() const { return _klass; }
1370 const void* user_data() const { return _user_data; }
1371
1372 // indicates if the iteration has been aborted
1373 bool _iteration_aborted;
1374 bool is_iteration_aborted() const { return _iteration_aborted; }
1375
1376 // used to check the visit control flags. If the abort flag is set
1377 // then we set the iteration aborted flag so that the iteration completes
1378 // without processing any further objects
1379 bool check_flags_for_abort(jint flags) {
1380 bool is_abort = (flags & JVMTI_VISIT_ABORT) != 0;
1381 if (is_abort) {
1382 _iteration_aborted = true;
1383 }
1384 return is_abort;
1385 }
1386
1387 public:
1388 IterateThroughHeapObjectClosure(JvmtiTagMap* tag_map,
1389 Klass* klass,
1390 int heap_filter,
1391 const jvmtiHeapCallbacks* heap_callbacks,
1392 const void* user_data) :
1393 _tag_map(tag_map),
1394 _klass(klass),
1395 _heap_filter(heap_filter),
1396 _callbacks(heap_callbacks),
1397 _user_data(user_data),
1398 _iteration_aborted(false)
1399 {
1400 }
1401
1402 void do_object(oop o);
1403 };
1404
1405 // invoked for each object in the heap
1406 void IterateThroughHeapObjectClosure::do_object(oop obj) {
1407 // check if iteration has been halted
1408 if (is_iteration_aborted()) return;
1409
1410 // ignore any objects that aren't visible to profiler
1411 if (!ServiceUtil::visible_oop(obj)) return;
1412
1413 // apply class filter
1414 if (is_filtered_by_klass_filter(obj, klass())) return;
1415
1416 // prepare for callback
1417 CallbackWrapper wrapper(tag_map(), obj);
1418
1419 // check if filtered by the heap filter
1420 if (is_filtered_by_heap_filter(wrapper.obj_tag(), wrapper.klass_tag(), heap_filter())) {
1421 return;
1422 }
1423
1424 // for arrays we need the length, otherwise -1
1425 bool is_array = obj->is_array();
1426 int len = is_array ? arrayOop(obj)->length() : -1;
1427
1428 // invoke the object callback (if callback is provided)
1429 if (callbacks()->heap_iteration_callback != NULL) {
1430 jvmtiHeapIterationCallback cb = callbacks()->heap_iteration_callback;
1431 jint res = (*cb)(wrapper.klass_tag(),
1432 wrapper.obj_size(),
1433 wrapper.obj_tag_p(),
1434 (jint)len,
1435 (void*)user_data());
1436 if (check_flags_for_abort(res)) return;
1437 }
1438
1439 // for objects and classes we report primitive fields if callback provided
1440 if (callbacks()->primitive_field_callback != NULL && obj->is_instance()) {
1441 jint res;
1442 jvmtiPrimitiveFieldCallback cb = callbacks()->primitive_field_callback;
1443 if (obj->klass() == SystemDictionary::Class_klass()) {
1444 res = invoke_primitive_field_callback_for_static_fields(&wrapper,
1445 obj,
1446 cb,
1447 (void*)user_data());
1448 } else {
1449 res = invoke_primitive_field_callback_for_instance_fields(&wrapper,
1450 obj,
1451 cb,
1452 (void*)user_data());
1453 }
1454 if (check_flags_for_abort(res)) return;
1455 }
1456
1457 // string callback
1458 if (!is_array &&
1459 callbacks()->string_primitive_value_callback != NULL &&
1460 obj->klass() == SystemDictionary::String_klass()) {
1461 jint res = invoke_string_value_callback(
1462 callbacks()->string_primitive_value_callback,
1463 &wrapper,
1464 obj,
1465 (void*)user_data() );
1466 if (check_flags_for_abort(res)) return;
1467 }
1468
1469 // array callback
1470 if (is_array &&
1471 callbacks()->array_primitive_value_callback != NULL &&
1472 obj->is_typeArray()) {
1473 jint res = invoke_array_primitive_value_callback(
1474 callbacks()->array_primitive_value_callback,
1475 &wrapper,
1476 obj,
1477 (void*)user_data() );
1478 if (check_flags_for_abort(res)) return;
1479 }
1480 };
1481
1482
1483 // Deprecated function to iterate over all objects in the heap
1484 void JvmtiTagMap::iterate_over_heap(jvmtiHeapObjectFilter object_filter,
1485 Klass* klass,
1486 jvmtiHeapObjectCallback heap_object_callback,
1487 const void* user_data)
1488 {
1489 MutexLocker ml(Heap_lock);
1490 IterateOverHeapObjectClosure blk(this,
1491 klass,
1492 object_filter,
1493 heap_object_callback,
1494 user_data);
1495 VM_HeapIterateOperation op(&blk);
1496 VMThread::execute(&op);
1497 }
1498
1499
1500 // Iterates over all objects in the heap
1501 void JvmtiTagMap::iterate_through_heap(jint heap_filter,
1502 Klass* klass,
1503 const jvmtiHeapCallbacks* callbacks,
1504 const void* user_data)
1505 {
1506 MutexLocker ml(Heap_lock);
1507 IterateThroughHeapObjectClosure blk(this,
1508 klass,
1509 heap_filter,
1510 callbacks,
1511 user_data);
1512 VM_HeapIterateOperation op(&blk);
1513 VMThread::execute(&op);
1514 }
1515
1516 // support class for get_objects_with_tags
1517
1518 class TagObjectCollector : public JvmtiTagHashmapEntryClosure {
1519 private:
1520 JvmtiEnv* _env;
1521 jlong* _tags;
1522 jint _tag_count;
1523
1524 GrowableArray<jobject>* _object_results; // collected objects (JNI weak refs)
1525 GrowableArray<uint64_t>* _tag_results; // collected tags
1526
1527 public:
1528 TagObjectCollector(JvmtiEnv* env, const jlong* tags, jint tag_count) {
1529 _env = env;
1530 _tags = (jlong*)tags;
1531 _tag_count = tag_count;
1532 _object_results = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<jobject>(1,true);
1533 _tag_results = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<uint64_t>(1,true);
1534 }
1535
1536 ~TagObjectCollector() {
1537 delete _object_results;
1538 delete _tag_results;
1539 }
1540
1541 // for each tagged object check if the tag value matches
1542 // - if it matches then we create a JNI local reference to the object
1543 // and record the reference and tag value.
1544 //
1545 void do_entry(JvmtiTagHashmapEntry* entry) {
1546 for (int i=0; i<_tag_count; i++) {
1547 if (_tags[i] == entry->tag()) {
1548 // The reference in this tag map could be the only (implicitly weak)
1549 // reference to that object. If we hand it out, we need to keep it live wrt
1550 // SATB marking similar to other j.l.ref.Reference referents. This is
1551 // achieved by using a phantom load in the object() accessor.
1552 oop o = entry->object();
1553 assert(o != NULL && Universe::heap()->is_in_reserved(o), "sanity check");
1554 jobject ref = JNIHandles::make_local(JavaThread::current(), o);
1555 _object_results->append(ref);
1556 _tag_results->append((uint64_t)entry->tag());
1557 }
1558 }
1559 }
1560
1561 // return the results from the collection
1562 //
1563 jvmtiError result(jint* count_ptr, jobject** object_result_ptr, jlong** tag_result_ptr) {
1564 jvmtiError error;
1565 int count = _object_results->length();
1566 assert(count >= 0, "sanity check");
1567
1568 // if object_result_ptr is not NULL then allocate the result and copy
1569 // in the object references.
1570 if (object_result_ptr != NULL) {
1571 error = _env->Allocate(count * sizeof(jobject), (unsigned char**)object_result_ptr);
1572 if (error != JVMTI_ERROR_NONE) {
1573 return error;
1574 }
1575 for (int i=0; i<count; i++) {
1576 (*object_result_ptr)[i] = _object_results->at(i);
1577 }
1578 }
1579
1580 // if tag_result_ptr is not NULL then allocate the result and copy
1581 // in the tag values.
1582 if (tag_result_ptr != NULL) {
1583 error = _env->Allocate(count * sizeof(jlong), (unsigned char**)tag_result_ptr);
1584 if (error != JVMTI_ERROR_NONE) {
1585 if (object_result_ptr != NULL) {
1586 _env->Deallocate((unsigned char*)object_result_ptr);
1587 }
1588 return error;
1589 }
1590 for (int i=0; i<count; i++) {
1591 (*tag_result_ptr)[i] = (jlong)_tag_results->at(i);
1592 }
1593 }
1594
1595 *count_ptr = count;
1596 return JVMTI_ERROR_NONE;
1597 }
1598 };
1599
1600 // return the list of objects with the specified tags
1601 jvmtiError JvmtiTagMap::get_objects_with_tags(const jlong* tags,
1602 jint count, jint* count_ptr, jobject** object_result_ptr, jlong** tag_result_ptr) {
1603
1604 TagObjectCollector collector(env(), tags, count);
1605 {
1606 // iterate over all tagged objects
1607 MutexLocker ml(lock());
1608 entry_iterate(&collector);
1609 }
1610 return collector.result(count_ptr, object_result_ptr, tag_result_ptr);
1611 }
1612
1613
1614 // ObjectMarker is used to support the marking objects when walking the
1615 // heap.
1616 //
1617 // This implementation uses the existing mark bits in an object for
1618 // marking. Objects that are marked must later have their headers restored.
1619 // As most objects are unlocked and don't have their identity hash computed
1620 // we don't have to save their headers. Instead we save the headers that
1621 // are "interesting". Later when the headers are restored this implementation
1622 // restores all headers to their initial value and then restores the few
1623 // objects that had interesting headers.
1624 //
1625 // Future work: This implementation currently uses growable arrays to save
1626 // the oop and header of interesting objects. As an optimization we could
1627 // use the same technique as the GC and make use of the unused area
1628 // between top() and end().
1629 //
1630
1631 // An ObjectClosure used to restore the mark bits of an object
1632 class RestoreMarksClosure : public ObjectClosure {
1633 public:
1634 void do_object(oop o) {
1635 if (o != NULL) {
1636 markOop mark = o->mark();
1637 if (mark->is_marked()) {
1638 o->init_mark();
1639 }
1640 }
1641 }
1642 };
1643
1644 // ObjectMarker provides the mark and visited functions
1645 class ObjectMarker : AllStatic {
1646 private:
1647 // saved headers
1648 static GrowableArray<oop>* _saved_oop_stack;
1649 static GrowableArray<markOop>* _saved_mark_stack;
1650 static bool _needs_reset; // do we need to reset mark bits?
1651
1652 public:
1653 static void init(); // initialize
1654 static void done(); // clean-up
1655
1656 static inline void mark(oop o); // mark an object
1657 static inline bool visited(oop o); // check if object has been visited
1658
1659 static inline bool needs_reset() { return _needs_reset; }
1660 static inline void set_needs_reset(bool v) { _needs_reset = v; }
1661 };
1662
1663 GrowableArray<oop>* ObjectMarker::_saved_oop_stack = NULL;
1664 GrowableArray<markOop>* ObjectMarker::_saved_mark_stack = NULL;
1665 bool ObjectMarker::_needs_reset = true; // need to reset mark bits by default
1666
1667 // initialize ObjectMarker - prepares for object marking
1668 void ObjectMarker::init() {
1669 assert(Thread::current()->is_VM_thread(), "must be VMThread");
1670
1671 // prepare heap for iteration
1672 Universe::heap()->ensure_parsability(false); // no need to retire TLABs
1673
1674 // create stacks for interesting headers
1675 _saved_mark_stack = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<markOop>(4000, true);
1676 _saved_oop_stack = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<oop>(4000, true);
1677
1678 if (UseBiasedLocking) {
1679 BiasedLocking::preserve_marks();
1680 }
1681 }
1682
1683 // Object marking is done so restore object headers
1684 void ObjectMarker::done() {
1685 // iterate over all objects and restore the mark bits to
1686 // their initial value
1687 RestoreMarksClosure blk;
1688 if (needs_reset()) {
1689 Universe::heap()->object_iterate(&blk);
1690 } else {
1691 // We don't need to reset mark bits on this call, but reset the
1692 // flag to the default for the next call.
1693 set_needs_reset(true);
1694 }
1695
1696 // now restore the interesting headers
1697 for (int i = 0; i < _saved_oop_stack->length(); i++) {
1698 oop o = _saved_oop_stack->at(i);
1699 markOop mark = _saved_mark_stack->at(i);
1700 o->set_mark(mark);
1701 }
1702
1703 if (UseBiasedLocking) {
1704 BiasedLocking::restore_marks();
1705 }
1706
1707 // free the stacks
1708 delete _saved_oop_stack;
1709 delete _saved_mark_stack;
1710 }
1711
1712 // mark an object
1713 inline void ObjectMarker::mark(oop o) {
1714 assert(Universe::heap()->is_in(o), "sanity check");
1715 assert(!o->mark()->is_marked(), "should only mark an object once");
1716
1717 // object's mark word
1718 markOop mark = o->mark();
1719
1720 if (mark->must_be_preserved(o)) {
1721 _saved_mark_stack->push(mark);
1722 _saved_oop_stack->push(o);
1723 }
1724
1725 // mark the object
1726 o->set_mark(markOopDesc::prototype()->set_marked());
1727 }
1728
1729 // return true if object is marked
1730 inline bool ObjectMarker::visited(oop o) {
1731 return o->mark()->is_marked();
1732 }
1733
1734 // Stack allocated class to help ensure that ObjectMarker is used
1735 // correctly. Constructor initializes ObjectMarker, destructor calls
1736 // ObjectMarker's done() function to restore object headers.
1737 class ObjectMarkerController : public StackObj {
1738 public:
1739 ObjectMarkerController() {
1740 ObjectMarker::init();
1741 }
1742 ~ObjectMarkerController() {
1743 ObjectMarker::done();
1744 }
1745 };
1746
1747
1748 // helper to map a jvmtiHeapReferenceKind to an old style jvmtiHeapRootKind
1749 // (not performance critical as only used for roots)
1750 static jvmtiHeapRootKind toJvmtiHeapRootKind(jvmtiHeapReferenceKind kind) {
1751 switch (kind) {
1752 case JVMTI_HEAP_REFERENCE_JNI_GLOBAL: return JVMTI_HEAP_ROOT_JNI_GLOBAL;
1753 case JVMTI_HEAP_REFERENCE_SYSTEM_CLASS: return JVMTI_HEAP_ROOT_SYSTEM_CLASS;
1754 case JVMTI_HEAP_REFERENCE_MONITOR: return JVMTI_HEAP_ROOT_MONITOR;
1755 case JVMTI_HEAP_REFERENCE_STACK_LOCAL: return JVMTI_HEAP_ROOT_STACK_LOCAL;
1756 case JVMTI_HEAP_REFERENCE_JNI_LOCAL: return JVMTI_HEAP_ROOT_JNI_LOCAL;
1757 case JVMTI_HEAP_REFERENCE_THREAD: return JVMTI_HEAP_ROOT_THREAD;
1758 case JVMTI_HEAP_REFERENCE_OTHER: return JVMTI_HEAP_ROOT_OTHER;
1759 default: ShouldNotReachHere(); return JVMTI_HEAP_ROOT_OTHER;
1760 }
1761 }
1762
1763 // Base class for all heap walk contexts. The base class maintains a flag
1764 // to indicate if the context is valid or not.
1765 class HeapWalkContext VALUE_OBJ_CLASS_SPEC {
1766 private:
1767 bool _valid;
1768 public:
1769 HeapWalkContext(bool valid) { _valid = valid; }
1770 void invalidate() { _valid = false; }
1771 bool is_valid() const { return _valid; }
1772 };
1773
1774 // A basic heap walk context for the deprecated heap walking functions.
1775 // The context for a basic heap walk are the callbacks and fields used by
1776 // the referrer caching scheme.
1777 class BasicHeapWalkContext: public HeapWalkContext {
1778 private:
1779 jvmtiHeapRootCallback _heap_root_callback;
1780 jvmtiStackReferenceCallback _stack_ref_callback;
1781 jvmtiObjectReferenceCallback _object_ref_callback;
1782
1783 // used for caching
1784 oop _last_referrer;
1785 jlong _last_referrer_tag;
1786
1787 public:
1788 BasicHeapWalkContext() : HeapWalkContext(false) { }
1789
1790 BasicHeapWalkContext(jvmtiHeapRootCallback heap_root_callback,
1791 jvmtiStackReferenceCallback stack_ref_callback,
1792 jvmtiObjectReferenceCallback object_ref_callback) :
1793 HeapWalkContext(true),
1794 _heap_root_callback(heap_root_callback),
1795 _stack_ref_callback(stack_ref_callback),
1796 _object_ref_callback(object_ref_callback),
1797 _last_referrer(NULL),
1798 _last_referrer_tag(0) {
1799 }
1800
1801 // accessors
1802 jvmtiHeapRootCallback heap_root_callback() const { return _heap_root_callback; }
1803 jvmtiStackReferenceCallback stack_ref_callback() const { return _stack_ref_callback; }
1804 jvmtiObjectReferenceCallback object_ref_callback() const { return _object_ref_callback; }
1805
1806 oop last_referrer() const { return _last_referrer; }
1807 void set_last_referrer(oop referrer) { _last_referrer = referrer; }
1808 jlong last_referrer_tag() const { return _last_referrer_tag; }
1809 void set_last_referrer_tag(jlong value) { _last_referrer_tag = value; }
1810 };
1811
1812 // The advanced heap walk context for the FollowReferences functions.
1813 // The context is the callbacks, and the fields used for filtering.
1814 class AdvancedHeapWalkContext: public HeapWalkContext {
1815 private:
1816 jint _heap_filter;
1817 Klass* _klass_filter;
1818 const jvmtiHeapCallbacks* _heap_callbacks;
1819
1820 public:
1821 AdvancedHeapWalkContext() : HeapWalkContext(false) { }
1822
1823 AdvancedHeapWalkContext(jint heap_filter,
1824 Klass* klass_filter,
1825 const jvmtiHeapCallbacks* heap_callbacks) :
1826 HeapWalkContext(true),
1827 _heap_filter(heap_filter),
1828 _klass_filter(klass_filter),
1829 _heap_callbacks(heap_callbacks) {
1830 }
1831
1832 // accessors
1833 jint heap_filter() const { return _heap_filter; }
1834 Klass* klass_filter() const { return _klass_filter; }
1835
1836 const jvmtiHeapReferenceCallback heap_reference_callback() const {
1837 return _heap_callbacks->heap_reference_callback;
1838 };
1839 const jvmtiPrimitiveFieldCallback primitive_field_callback() const {
1840 return _heap_callbacks->primitive_field_callback;
1841 }
1842 const jvmtiArrayPrimitiveValueCallback array_primitive_value_callback() const {
1843 return _heap_callbacks->array_primitive_value_callback;
1844 }
1845 const jvmtiStringPrimitiveValueCallback string_primitive_value_callback() const {
1846 return _heap_callbacks->string_primitive_value_callback;
1847 }
1848 };
1849
1850 // The CallbackInvoker is a class with static functions that the heap walk can call
1851 // into to invoke callbacks. It works in one of two modes. The "basic" mode is
1852 // used for the deprecated IterateOverReachableObjects functions. The "advanced"
1853 // mode is for the newer FollowReferences function which supports a lot of
1854 // additional callbacks.
1855 class CallbackInvoker : AllStatic {
1856 private:
1857 // heap walk styles
1858 enum { basic, advanced };
1859 static int _heap_walk_type;
1860 static bool is_basic_heap_walk() { return _heap_walk_type == basic; }
1861 static bool is_advanced_heap_walk() { return _heap_walk_type == advanced; }
1862
1863 // context for basic style heap walk
1864 static BasicHeapWalkContext _basic_context;
1865 static BasicHeapWalkContext* basic_context() {
1866 assert(_basic_context.is_valid(), "invalid");
1867 return &_basic_context;
1868 }
1869
1870 // context for advanced style heap walk
1871 static AdvancedHeapWalkContext _advanced_context;
1872 static AdvancedHeapWalkContext* advanced_context() {
1873 assert(_advanced_context.is_valid(), "invalid");
1874 return &_advanced_context;
1875 }
1876
1877 // context needed for all heap walks
1878 static JvmtiTagMap* _tag_map;
1879 static const void* _user_data;
1880 static GrowableArray<oop>* _visit_stack;
1881
1882 // accessors
1883 static JvmtiTagMap* tag_map() { return _tag_map; }
1884 static const void* user_data() { return _user_data; }
1885 static GrowableArray<oop>* visit_stack() { return _visit_stack; }
1886
1887 // if the object hasn't been visited then push it onto the visit stack
1888 // so that it will be visited later
1889 static inline bool check_for_visit(oop obj) {
1890 if (!ObjectMarker::visited(obj)) visit_stack()->push(obj);
1891 return true;
1892 }
1893
1894 // invoke basic style callbacks
1895 static inline bool invoke_basic_heap_root_callback
1896 (jvmtiHeapRootKind root_kind, oop obj);
1897 static inline bool invoke_basic_stack_ref_callback
1898 (jvmtiHeapRootKind root_kind, jlong thread_tag, jint depth, jmethodID method,
1899 int slot, oop obj);
1900 static inline bool invoke_basic_object_reference_callback
1901 (jvmtiObjectReferenceKind ref_kind, oop referrer, oop referree, jint index);
1902
1903 // invoke advanced style callbacks
1904 static inline bool invoke_advanced_heap_root_callback
1905 (jvmtiHeapReferenceKind ref_kind, oop obj);
1906 static inline bool invoke_advanced_stack_ref_callback
1907 (jvmtiHeapReferenceKind ref_kind, jlong thread_tag, jlong tid, int depth,
1908 jmethodID method, jlocation bci, jint slot, oop obj);
1909 static inline bool invoke_advanced_object_reference_callback
1910 (jvmtiHeapReferenceKind ref_kind, oop referrer, oop referree, jint index);
1911
1912 // used to report the value of primitive fields
1913 static inline bool report_primitive_field
1914 (jvmtiHeapReferenceKind ref_kind, oop obj, jint index, address addr, char type);
1915
1916 public:
1917 // initialize for basic mode
1918 static void initialize_for_basic_heap_walk(JvmtiTagMap* tag_map,
1919 GrowableArray<oop>* visit_stack,
1920 const void* user_data,
1921 BasicHeapWalkContext context);
1922
1923 // initialize for advanced mode
1924 static void initialize_for_advanced_heap_walk(JvmtiTagMap* tag_map,
1925 GrowableArray<oop>* visit_stack,
1926 const void* user_data,
1927 AdvancedHeapWalkContext context);
1928
1929 // functions to report roots
1930 static inline bool report_simple_root(jvmtiHeapReferenceKind kind, oop o);
1931 static inline bool report_jni_local_root(jlong thread_tag, jlong tid, jint depth,
1932 jmethodID m, oop o);
1933 static inline bool report_stack_ref_root(jlong thread_tag, jlong tid, jint depth,
1934 jmethodID method, jlocation bci, jint slot, oop o);
1935
1936 // functions to report references
1937 static inline bool report_array_element_reference(oop referrer, oop referree, jint index);
1938 static inline bool report_class_reference(oop referrer, oop referree);
1939 static inline bool report_class_loader_reference(oop referrer, oop referree);
1940 static inline bool report_signers_reference(oop referrer, oop referree);
1941 static inline bool report_protection_domain_reference(oop referrer, oop referree);
1942 static inline bool report_superclass_reference(oop referrer, oop referree);
1943 static inline bool report_interface_reference(oop referrer, oop referree);
1944 static inline bool report_static_field_reference(oop referrer, oop referree, jint slot);
1945 static inline bool report_field_reference(oop referrer, oop referree, jint slot);
1946 static inline bool report_constant_pool_reference(oop referrer, oop referree, jint index);
1947 static inline bool report_primitive_array_values(oop array);
1948 static inline bool report_string_value(oop str);
1949 static inline bool report_primitive_instance_field(oop o, jint index, address value, char type);
1950 static inline bool report_primitive_static_field(oop o, jint index, address value, char type);
1951 };
1952
1953 // statics
1954 int CallbackInvoker::_heap_walk_type;
1955 BasicHeapWalkContext CallbackInvoker::_basic_context;
1956 AdvancedHeapWalkContext CallbackInvoker::_advanced_context;
1957 JvmtiTagMap* CallbackInvoker::_tag_map;
1958 const void* CallbackInvoker::_user_data;
1959 GrowableArray<oop>* CallbackInvoker::_visit_stack;
1960
1961 // initialize for basic heap walk (IterateOverReachableObjects et al)
1962 void CallbackInvoker::initialize_for_basic_heap_walk(JvmtiTagMap* tag_map,
1963 GrowableArray<oop>* visit_stack,
1964 const void* user_data,
1965 BasicHeapWalkContext context) {
1966 _tag_map = tag_map;
1967 _visit_stack = visit_stack;
1968 _user_data = user_data;
1969 _basic_context = context;
1970 _advanced_context.invalidate(); // will trigger assertion if used
1971 _heap_walk_type = basic;
1972 }
1973
1974 // initialize for advanced heap walk (FollowReferences)
1975 void CallbackInvoker::initialize_for_advanced_heap_walk(JvmtiTagMap* tag_map,
1976 GrowableArray<oop>* visit_stack,
1977 const void* user_data,
1978 AdvancedHeapWalkContext context) {
1979 _tag_map = tag_map;
1980 _visit_stack = visit_stack;
1981 _user_data = user_data;
1982 _advanced_context = context;
1983 _basic_context.invalidate(); // will trigger assertion if used
1984 _heap_walk_type = advanced;
1985 }
1986
1987
1988 // invoke basic style heap root callback
1989 inline bool CallbackInvoker::invoke_basic_heap_root_callback(jvmtiHeapRootKind root_kind, oop obj) {
1990 assert(ServiceUtil::visible_oop(obj), "checking");
1991
1992 // if we heap roots should be reported
1993 jvmtiHeapRootCallback cb = basic_context()->heap_root_callback();
1994 if (cb == NULL) {
1995 return check_for_visit(obj);
1996 }
1997
1998 CallbackWrapper wrapper(tag_map(), obj);
1999 jvmtiIterationControl control = (*cb)(root_kind,
2000 wrapper.klass_tag(),
2001 wrapper.obj_size(),
2002 wrapper.obj_tag_p(),
2003 (void*)user_data());
2004 // push root to visit stack when following references
2005 if (control == JVMTI_ITERATION_CONTINUE &&
2006 basic_context()->object_ref_callback() != NULL) {
2007 visit_stack()->push(obj);
2008 }
2009 return control != JVMTI_ITERATION_ABORT;
2010 }
2011
2012 // invoke basic style stack ref callback
2013 inline bool CallbackInvoker::invoke_basic_stack_ref_callback(jvmtiHeapRootKind root_kind,
2014 jlong thread_tag,
2015 jint depth,
2016 jmethodID method,
2017 int slot,
2018 oop obj) {
2019 assert(ServiceUtil::visible_oop(obj), "checking");
2020
2021 // if we stack refs should be reported
2022 jvmtiStackReferenceCallback cb = basic_context()->stack_ref_callback();
2023 if (cb == NULL) {
2024 return check_for_visit(obj);
2025 }
2026
2027 CallbackWrapper wrapper(tag_map(), obj);
2028 jvmtiIterationControl control = (*cb)(root_kind,
2029 wrapper.klass_tag(),
2030 wrapper.obj_size(),
2031 wrapper.obj_tag_p(),
2032 thread_tag,
2033 depth,
2034 method,
2035 slot,
2036 (void*)user_data());
2037 // push root to visit stack when following references
2038 if (control == JVMTI_ITERATION_CONTINUE &&
2039 basic_context()->object_ref_callback() != NULL) {
2040 visit_stack()->push(obj);
2041 }
2042 return control != JVMTI_ITERATION_ABORT;
2043 }
2044
2045 // invoke basic style object reference callback
2046 inline bool CallbackInvoker::invoke_basic_object_reference_callback(jvmtiObjectReferenceKind ref_kind,
2047 oop referrer,
2048 oop referree,
2049 jint index) {
2050
2051 assert(ServiceUtil::visible_oop(referrer), "checking");
2052 assert(ServiceUtil::visible_oop(referree), "checking");
2053
2054 BasicHeapWalkContext* context = basic_context();
2055
2056 // callback requires the referrer's tag. If it's the same referrer
2057 // as the last call then we use the cached value.
2058 jlong referrer_tag;
2059 if (referrer == context->last_referrer()) {
2060 referrer_tag = context->last_referrer_tag();
2061 } else {
2062 referrer_tag = tag_for(tag_map(), referrer);
2063 }
2064
2065 // do the callback
2066 CallbackWrapper wrapper(tag_map(), referree);
2067 jvmtiObjectReferenceCallback cb = context->object_ref_callback();
2068 jvmtiIterationControl control = (*cb)(ref_kind,
2069 wrapper.klass_tag(),
2070 wrapper.obj_size(),
2071 wrapper.obj_tag_p(),
2072 referrer_tag,
2073 index,
2074 (void*)user_data());
2075
2076 // record referrer and referrer tag. For self-references record the
2077 // tag value from the callback as this might differ from referrer_tag.
2078 context->set_last_referrer(referrer);
2079 if (referrer == referree) {
2080 context->set_last_referrer_tag(*wrapper.obj_tag_p());
2081 } else {
2082 context->set_last_referrer_tag(referrer_tag);
2083 }
2084
2085 if (control == JVMTI_ITERATION_CONTINUE) {
2086 return check_for_visit(referree);
2087 } else {
2088 return control != JVMTI_ITERATION_ABORT;
2089 }
2090 }
2091
2092 // invoke advanced style heap root callback
2093 inline bool CallbackInvoker::invoke_advanced_heap_root_callback(jvmtiHeapReferenceKind ref_kind,
2094 oop obj) {
2095 assert(ServiceUtil::visible_oop(obj), "checking");
2096
2097 AdvancedHeapWalkContext* context = advanced_context();
2098
2099 // check that callback is provided
2100 jvmtiHeapReferenceCallback cb = context->heap_reference_callback();
2101 if (cb == NULL) {
2102 return check_for_visit(obj);
2103 }
2104
2105 // apply class filter
2106 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
2107 return check_for_visit(obj);
2108 }
2109
2110 // setup the callback wrapper
2111 CallbackWrapper wrapper(tag_map(), obj);
2112
2113 // apply tag filter
2114 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2115 wrapper.klass_tag(),
2116 context->heap_filter())) {
2117 return check_for_visit(obj);
2118 }
2119
2120 // for arrays we need the length, otherwise -1
2121 jint len = (jint)(obj->is_array() ? arrayOop(obj)->length() : -1);
2122
2123 // invoke the callback
2124 jint res = (*cb)(ref_kind,
2125 NULL, // referrer info
2126 wrapper.klass_tag(),
2127 0, // referrer_class_tag is 0 for heap root
2128 wrapper.obj_size(),
2129 wrapper.obj_tag_p(),
2130 NULL, // referrer_tag_p
2131 len,
2132 (void*)user_data());
2133 if (res & JVMTI_VISIT_ABORT) {
2134 return false;// referrer class tag
2135 }
2136 if (res & JVMTI_VISIT_OBJECTS) {
2137 check_for_visit(obj);
2138 }
2139 return true;
2140 }
2141
2142 // report a reference from a thread stack to an object
2143 inline bool CallbackInvoker::invoke_advanced_stack_ref_callback(jvmtiHeapReferenceKind ref_kind,
2144 jlong thread_tag,
2145 jlong tid,
2146 int depth,
2147 jmethodID method,
2148 jlocation bci,
2149 jint slot,
2150 oop obj) {
2151 assert(ServiceUtil::visible_oop(obj), "checking");
2152
2153 AdvancedHeapWalkContext* context = advanced_context();
2154
2155 // check that callback is provider
2156 jvmtiHeapReferenceCallback cb = context->heap_reference_callback();
2157 if (cb == NULL) {
2158 return check_for_visit(obj);
2159 }
2160
2161 // apply class filter
2162 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
2163 return check_for_visit(obj);
2164 }
2165
2166 // setup the callback wrapper
2167 CallbackWrapper wrapper(tag_map(), obj);
2168
2169 // apply tag filter
2170 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2171 wrapper.klass_tag(),
2172 context->heap_filter())) {
2173 return check_for_visit(obj);
2174 }
2175
2176 // setup the referrer info
2177 jvmtiHeapReferenceInfo reference_info;
2178 reference_info.stack_local.thread_tag = thread_tag;
2179 reference_info.stack_local.thread_id = tid;
2180 reference_info.stack_local.depth = depth;
2181 reference_info.stack_local.method = method;
2182 reference_info.stack_local.location = bci;
2183 reference_info.stack_local.slot = slot;
2184
2185 // for arrays we need the length, otherwise -1
2186 jint len = (jint)(obj->is_array() ? arrayOop(obj)->length() : -1);
2187
2188 // call into the agent
2189 int res = (*cb)(ref_kind,
2190 &reference_info,
2191 wrapper.klass_tag(),
2192 0, // referrer_class_tag is 0 for heap root (stack)
2193 wrapper.obj_size(),
2194 wrapper.obj_tag_p(),
2195 NULL, // referrer_tag is 0 for root
2196 len,
2197 (void*)user_data());
2198
2199 if (res & JVMTI_VISIT_ABORT) {
2200 return false;
2201 }
2202 if (res & JVMTI_VISIT_OBJECTS) {
2203 check_for_visit(obj);
2204 }
2205 return true;
2206 }
2207
2208 // This mask is used to pass reference_info to a jvmtiHeapReferenceCallback
2209 // only for ref_kinds defined by the JVM TI spec. Otherwise, NULL is passed.
2210 #define REF_INFO_MASK ((1 << JVMTI_HEAP_REFERENCE_FIELD) \
2211 | (1 << JVMTI_HEAP_REFERENCE_STATIC_FIELD) \
2212 | (1 << JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT) \
2213 | (1 << JVMTI_HEAP_REFERENCE_CONSTANT_POOL) \
2214 | (1 << JVMTI_HEAP_REFERENCE_STACK_LOCAL) \
2215 | (1 << JVMTI_HEAP_REFERENCE_JNI_LOCAL))
2216
2217 // invoke the object reference callback to report a reference
2218 inline bool CallbackInvoker::invoke_advanced_object_reference_callback(jvmtiHeapReferenceKind ref_kind,
2219 oop referrer,
2220 oop obj,
2221 jint index)
2222 {
2223 // field index is only valid field in reference_info
2224 static jvmtiHeapReferenceInfo reference_info = { 0 };
2225
2226 assert(ServiceUtil::visible_oop(referrer), "checking");
2227 assert(ServiceUtil::visible_oop(obj), "checking");
2228
2229 AdvancedHeapWalkContext* context = advanced_context();
2230
2231 // check that callback is provider
2232 jvmtiHeapReferenceCallback cb = context->heap_reference_callback();
2233 if (cb == NULL) {
2234 return check_for_visit(obj);
2235 }
2236
2237 // apply class filter
2238 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
2239 return check_for_visit(obj);
2240 }
2241
2242 // setup the callback wrapper
2243 TwoOopCallbackWrapper wrapper(tag_map(), referrer, obj);
2244
2245 // apply tag filter
2246 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2247 wrapper.klass_tag(),
2248 context->heap_filter())) {
2249 return check_for_visit(obj);
2250 }
2251
2252 // field index is only valid field in reference_info
2253 reference_info.field.index = index;
2254
2255 // for arrays we need the length, otherwise -1
2256 jint len = (jint)(obj->is_array() ? arrayOop(obj)->length() : -1);
2257
2258 // invoke the callback
2259 int res = (*cb)(ref_kind,
2260 (REF_INFO_MASK & (1 << ref_kind)) ? &reference_info : NULL,
2261 wrapper.klass_tag(),
2262 wrapper.referrer_klass_tag(),
2263 wrapper.obj_size(),
2264 wrapper.obj_tag_p(),
2265 wrapper.referrer_tag_p(),
2266 len,
2267 (void*)user_data());
2268
2269 if (res & JVMTI_VISIT_ABORT) {
2270 return false;
2271 }
2272 if (res & JVMTI_VISIT_OBJECTS) {
2273 check_for_visit(obj);
2274 }
2275 return true;
2276 }
2277
2278 // report a "simple root"
2279 inline bool CallbackInvoker::report_simple_root(jvmtiHeapReferenceKind kind, oop obj) {
2280 assert(kind != JVMTI_HEAP_REFERENCE_STACK_LOCAL &&
2281 kind != JVMTI_HEAP_REFERENCE_JNI_LOCAL, "not a simple root");
2282 assert(ServiceUtil::visible_oop(obj), "checking");
2283
2284 if (is_basic_heap_walk()) {
2285 // map to old style root kind
2286 jvmtiHeapRootKind root_kind = toJvmtiHeapRootKind(kind);
2287 return invoke_basic_heap_root_callback(root_kind, obj);
2288 } else {
2289 assert(is_advanced_heap_walk(), "wrong heap walk type");
2290 return invoke_advanced_heap_root_callback(kind, obj);
2291 }
2292 }
2293
2294
2295 // invoke the primitive array values
2296 inline bool CallbackInvoker::report_primitive_array_values(oop obj) {
2297 assert(obj->is_typeArray(), "not a primitive array");
2298
2299 AdvancedHeapWalkContext* context = advanced_context();
2300 assert(context->array_primitive_value_callback() != NULL, "no callback");
2301
2302 // apply class filter
2303 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
2304 return true;
2305 }
2306
2307 CallbackWrapper wrapper(tag_map(), obj);
2308
2309 // apply tag filter
2310 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2311 wrapper.klass_tag(),
2312 context->heap_filter())) {
2313 return true;
2314 }
2315
2316 // invoke the callback
2317 int res = invoke_array_primitive_value_callback(context->array_primitive_value_callback(),
2318 &wrapper,
2319 obj,
2320 (void*)user_data());
2321 return (!(res & JVMTI_VISIT_ABORT));
2322 }
2323
2324 // invoke the string value callback
2325 inline bool CallbackInvoker::report_string_value(oop str) {
2326 assert(str->klass() == SystemDictionary::String_klass(), "not a string");
2327
2328 AdvancedHeapWalkContext* context = advanced_context();
2329 assert(context->string_primitive_value_callback() != NULL, "no callback");
2330
2331 // apply class filter
2332 if (is_filtered_by_klass_filter(str, context->klass_filter())) {
2333 return true;
2334 }
2335
2336 CallbackWrapper wrapper(tag_map(), str);
2337
2338 // apply tag filter
2339 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2340 wrapper.klass_tag(),
2341 context->heap_filter())) {
2342 return true;
2343 }
2344
2345 // invoke the callback
2346 int res = invoke_string_value_callback(context->string_primitive_value_callback(),
2347 &wrapper,
2348 str,
2349 (void*)user_data());
2350 return (!(res & JVMTI_VISIT_ABORT));
2351 }
2352
2353 // invoke the primitive field callback
2354 inline bool CallbackInvoker::report_primitive_field(jvmtiHeapReferenceKind ref_kind,
2355 oop obj,
2356 jint index,
2357 address addr,
2358 char type)
2359 {
2360 // for primitive fields only the index will be set
2361 static jvmtiHeapReferenceInfo reference_info = { 0 };
2362
2363 AdvancedHeapWalkContext* context = advanced_context();
2364 assert(context->primitive_field_callback() != NULL, "no callback");
2365
2366 // apply class filter
2367 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
2368 return true;
2369 }
2370
2371 CallbackWrapper wrapper(tag_map(), obj);
2372
2373 // apply tag filter
2374 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2375 wrapper.klass_tag(),
2376 context->heap_filter())) {
2377 return true;
2378 }
2379
2380 // the field index in the referrer
2381 reference_info.field.index = index;
2382
2383 // map the type
2384 jvmtiPrimitiveType value_type = (jvmtiPrimitiveType)type;
2385
2386 // setup the jvalue
2387 jvalue value;
2388 copy_to_jvalue(&value, addr, value_type);
2389
2390 jvmtiPrimitiveFieldCallback cb = context->primitive_field_callback();
2391 int res = (*cb)(ref_kind,
2392 &reference_info,
2393 wrapper.klass_tag(),
2394 wrapper.obj_tag_p(),
2395 value,
2396 value_type,
2397 (void*)user_data());
2398 return (!(res & JVMTI_VISIT_ABORT));
2399 }
2400
2401
2402 // instance field
2403 inline bool CallbackInvoker::report_primitive_instance_field(oop obj,
2404 jint index,
2405 address value,
2406 char type) {
2407 return report_primitive_field(JVMTI_HEAP_REFERENCE_FIELD,
2408 obj,
2409 index,
2410 value,
2411 type);
2412 }
2413
2414 // static field
2415 inline bool CallbackInvoker::report_primitive_static_field(oop obj,
2416 jint index,
2417 address value,
2418 char type) {
2419 return report_primitive_field(JVMTI_HEAP_REFERENCE_STATIC_FIELD,
2420 obj,
2421 index,
2422 value,
2423 type);
2424 }
2425
2426 // report a JNI local (root object) to the profiler
2427 inline bool CallbackInvoker::report_jni_local_root(jlong thread_tag, jlong tid, jint depth, jmethodID m, oop obj) {
2428 if (is_basic_heap_walk()) {
2429 return invoke_basic_stack_ref_callback(JVMTI_HEAP_ROOT_JNI_LOCAL,
2430 thread_tag,
2431 depth,
2432 m,
2433 -1,
2434 obj);
2435 } else {
2436 return invoke_advanced_stack_ref_callback(JVMTI_HEAP_REFERENCE_JNI_LOCAL,
2437 thread_tag, tid,
2438 depth,
2439 m,
2440 (jlocation)-1,
2441 -1,
2442 obj);
2443 }
2444 }
2445
2446
2447 // report a local (stack reference, root object)
2448 inline bool CallbackInvoker::report_stack_ref_root(jlong thread_tag,
2449 jlong tid,
2450 jint depth,
2451 jmethodID method,
2452 jlocation bci,
2453 jint slot,
2454 oop obj) {
2455 if (is_basic_heap_walk()) {
2456 return invoke_basic_stack_ref_callback(JVMTI_HEAP_ROOT_STACK_LOCAL,
2457 thread_tag,
2458 depth,
2459 method,
2460 slot,
2461 obj);
2462 } else {
2463 return invoke_advanced_stack_ref_callback(JVMTI_HEAP_REFERENCE_STACK_LOCAL,
2464 thread_tag,
2465 tid,
2466 depth,
2467 method,
2468 bci,
2469 slot,
2470 obj);
2471 }
2472 }
2473
2474 // report an object referencing a class.
2475 inline bool CallbackInvoker::report_class_reference(oop referrer, oop referree) {
2476 if (is_basic_heap_walk()) {
2477 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CLASS, referrer, referree, -1);
2478 } else {
2479 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_CLASS, referrer, referree, -1);
2480 }
2481 }
2482
2483 // report a class referencing its class loader.
2484 inline bool CallbackInvoker::report_class_loader_reference(oop referrer, oop referree) {
2485 if (is_basic_heap_walk()) {
2486 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CLASS_LOADER, referrer, referree, -1);
2487 } else {
2488 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_CLASS_LOADER, referrer, referree, -1);
2489 }
2490 }
2491
2492 // report a class referencing its signers.
2493 inline bool CallbackInvoker::report_signers_reference(oop referrer, oop referree) {
2494 if (is_basic_heap_walk()) {
2495 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_SIGNERS, referrer, referree, -1);
2496 } else {
2497 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_SIGNERS, referrer, referree, -1);
2498 }
2499 }
2500
2501 // report a class referencing its protection domain..
2502 inline bool CallbackInvoker::report_protection_domain_reference(oop referrer, oop referree) {
2503 if (is_basic_heap_walk()) {
2504 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_PROTECTION_DOMAIN, referrer, referree, -1);
2505 } else {
2506 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_PROTECTION_DOMAIN, referrer, referree, -1);
2507 }
2508 }
2509
2510 // report a class referencing its superclass.
2511 inline bool CallbackInvoker::report_superclass_reference(oop referrer, oop referree) {
2512 if (is_basic_heap_walk()) {
2513 // Send this to be consistent with past implementation
2514 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CLASS, referrer, referree, -1);
2515 } else {
2516 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_SUPERCLASS, referrer, referree, -1);
2517 }
2518 }
2519
2520 // report a class referencing one of its interfaces.
2521 inline bool CallbackInvoker::report_interface_reference(oop referrer, oop referree) {
2522 if (is_basic_heap_walk()) {
2523 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_INTERFACE, referrer, referree, -1);
2524 } else {
2525 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_INTERFACE, referrer, referree, -1);
2526 }
2527 }
2528
2529 // report a class referencing one of its static fields.
2530 inline bool CallbackInvoker::report_static_field_reference(oop referrer, oop referree, jint slot) {
2531 if (is_basic_heap_walk()) {
2532 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_STATIC_FIELD, referrer, referree, slot);
2533 } else {
2534 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_STATIC_FIELD, referrer, referree, slot);
2535 }
2536 }
2537
2538 // report an array referencing an element object
2539 inline bool CallbackInvoker::report_array_element_reference(oop referrer, oop referree, jint index) {
2540 if (is_basic_heap_walk()) {
2541 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_ARRAY_ELEMENT, referrer, referree, index);
2542 } else {
2543 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT, referrer, referree, index);
2544 }
2545 }
2546
2547 // report an object referencing an instance field object
2548 inline bool CallbackInvoker::report_field_reference(oop referrer, oop referree, jint slot) {
2549 if (is_basic_heap_walk()) {
2550 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_FIELD, referrer, referree, slot);
2551 } else {
2552 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_FIELD, referrer, referree, slot);
2553 }
2554 }
2555
2556 // report an array referencing an element object
2557 inline bool CallbackInvoker::report_constant_pool_reference(oop referrer, oop referree, jint index) {
2558 if (is_basic_heap_walk()) {
2559 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CONSTANT_POOL, referrer, referree, index);
2560 } else {
2561 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_CONSTANT_POOL, referrer, referree, index);
2562 }
2563 }
2564
2565 // A supporting closure used to process simple roots
2566 class SimpleRootsClosure : public OopClosure {
2567 private:
2568 jvmtiHeapReferenceKind _kind;
2569 bool _continue;
2570
2571 jvmtiHeapReferenceKind root_kind() { return _kind; }
2572
2573 public:
2574 void set_kind(jvmtiHeapReferenceKind kind) {
2575 _kind = kind;
2576 _continue = true;
2577 }
2578
2579 inline bool stopped() {
2580 return !_continue;
2581 }
2582
2583 void do_oop(oop* obj_p) {
2584 // iteration has terminated
2585 if (stopped()) {
2586 return;
2587 }
2588
2589 oop o = *obj_p;
2590 // ignore null
2591 if (o == NULL) {
2592 return;
2593 }
2594
2595 assert(Universe::heap()->is_in_reserved(o), "should be impossible");
2596
2597 jvmtiHeapReferenceKind kind = root_kind();
2598 if (kind == JVMTI_HEAP_REFERENCE_SYSTEM_CLASS) {
2599 // SystemDictionary::always_strong_oops_do reports the application
2600 // class loader as a root. We want this root to be reported as
2601 // a root kind of "OTHER" rather than "SYSTEM_CLASS".
2602 if (!o->is_instance() || !InstanceKlass::cast(o->klass())->is_mirror_instance_klass()) {
2603 kind = JVMTI_HEAP_REFERENCE_OTHER;
2604 }
2605 }
2606
2607 // some objects are ignored - in the case of simple
2608 // roots it's mostly Symbol*s that we are skipping
2609 // here.
2610 if (!ServiceUtil::visible_oop(o)) {
2611 return;
2612 }
2613
2614 // invoke the callback
2615 _continue = CallbackInvoker::report_simple_root(kind, o);
2616
2617 }
2618 virtual void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }
2619 };
2620
2621 // A supporting closure used to process JNI locals
2622 class JNILocalRootsClosure : public OopClosure {
2623 private:
2624 jlong _thread_tag;
2625 jlong _tid;
2626 jint _depth;
2627 jmethodID _method;
2628 bool _continue;
2629 public:
2630 void set_context(jlong thread_tag, jlong tid, jint depth, jmethodID method) {
2631 _thread_tag = thread_tag;
2632 _tid = tid;
2633 _depth = depth;
2634 _method = method;
2635 _continue = true;
2636 }
2637
2638 inline bool stopped() {
2639 return !_continue;
2640 }
2641
2642 void do_oop(oop* obj_p) {
2643 // iteration has terminated
2644 if (stopped()) {
2645 return;
2646 }
2647
2648 oop o = *obj_p;
2649 // ignore null
2650 if (o == NULL) {
2651 return;
2652 }
2653
2654 if (!ServiceUtil::visible_oop(o)) {
2655 return;
2656 }
2657
2658 // invoke the callback
2659 _continue = CallbackInvoker::report_jni_local_root(_thread_tag, _tid, _depth, _method, o);
2660 }
2661 virtual void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }
2662 };
2663
2664
2665 // A VM operation to iterate over objects that are reachable from
2666 // a set of roots or an initial object.
2667 //
2668 // For VM_HeapWalkOperation the set of roots used is :-
2669 //
2670 // - All JNI global references
2671 // - All inflated monitors
2672 // - All classes loaded by the boot class loader (or all classes
2673 // in the event that class unloading is disabled)
2674 // - All java threads
2675 // - For each java thread then all locals and JNI local references
2676 // on the thread's execution stack
2677 // - All visible/explainable objects from Universes::oops_do
2678 //
2679 class VM_HeapWalkOperation: public VM_Operation {
2680 private:
2681 enum {
2682 initial_visit_stack_size = 4000
2683 };
2684
2685 bool _is_advanced_heap_walk; // indicates FollowReferences
2686 JvmtiTagMap* _tag_map;
2687 Handle _initial_object;
2688 GrowableArray<oop>* _visit_stack; // the visit stack
2689
2690 bool _collecting_heap_roots; // are we collecting roots
2691 bool _following_object_refs; // are we following object references
2692
2693 bool _reporting_primitive_fields; // optional reporting
2694 bool _reporting_primitive_array_values;
2695 bool _reporting_string_values;
2696
2697 GrowableArray<oop>* create_visit_stack() {
2698 return new (ResourceObj::C_HEAP, mtInternal) GrowableArray<oop>(initial_visit_stack_size, true);
2699 }
2700
2701 // accessors
2702 bool is_advanced_heap_walk() const { return _is_advanced_heap_walk; }
2703 JvmtiTagMap* tag_map() const { return _tag_map; }
2704 Handle initial_object() const { return _initial_object; }
2705
2706 bool is_following_references() const { return _following_object_refs; }
2707
2708 bool is_reporting_primitive_fields() const { return _reporting_primitive_fields; }
2709 bool is_reporting_primitive_array_values() const { return _reporting_primitive_array_values; }
2710 bool is_reporting_string_values() const { return _reporting_string_values; }
2711
2712 GrowableArray<oop>* visit_stack() const { return _visit_stack; }
2713
2714 // iterate over the various object types
2715 inline bool iterate_over_array(oop o);
2716 inline bool iterate_over_type_array(oop o);
2717 inline bool iterate_over_class(oop o);
2718 inline bool iterate_over_object(oop o);
2719
2720 // root collection
2721 inline bool collect_simple_roots();
2722 inline bool collect_stack_roots();
2723 inline bool collect_stack_roots(JavaThread* java_thread, JNILocalRootsClosure* blk);
2724
2725 // visit an object
2726 inline bool visit(oop o);
2727
2728 public:
2729 VM_HeapWalkOperation(JvmtiTagMap* tag_map,
2730 Handle initial_object,
2731 BasicHeapWalkContext callbacks,
2732 const void* user_data);
2733
2734 VM_HeapWalkOperation(JvmtiTagMap* tag_map,
2735 Handle initial_object,
2736 AdvancedHeapWalkContext callbacks,
2737 const void* user_data);
2738
2739 ~VM_HeapWalkOperation();
2740
2741 VMOp_Type type() const { return VMOp_HeapWalkOperation; }
2742 void doit();
2743 };
2744
2745
2746 VM_HeapWalkOperation::VM_HeapWalkOperation(JvmtiTagMap* tag_map,
2747 Handle initial_object,
2748 BasicHeapWalkContext callbacks,
2749 const void* user_data) {
2750 _is_advanced_heap_walk = false;
2751 _tag_map = tag_map;
2752 _initial_object = initial_object;
2753 _following_object_refs = (callbacks.object_ref_callback() != NULL);
2754 _reporting_primitive_fields = false;
2755 _reporting_primitive_array_values = false;
2756 _reporting_string_values = false;
2757 _visit_stack = create_visit_stack();
2758
2759
2760 CallbackInvoker::initialize_for_basic_heap_walk(tag_map, _visit_stack, user_data, callbacks);
2761 }
2762
2763 VM_HeapWalkOperation::VM_HeapWalkOperation(JvmtiTagMap* tag_map,
2764 Handle initial_object,
2765 AdvancedHeapWalkContext callbacks,
2766 const void* user_data) {
2767 _is_advanced_heap_walk = true;
2768 _tag_map = tag_map;
2769 _initial_object = initial_object;
2770 _following_object_refs = true;
2771 _reporting_primitive_fields = (callbacks.primitive_field_callback() != NULL);;
2772 _reporting_primitive_array_values = (callbacks.array_primitive_value_callback() != NULL);;
2773 _reporting_string_values = (callbacks.string_primitive_value_callback() != NULL);;
2774 _visit_stack = create_visit_stack();
2775
2776 CallbackInvoker::initialize_for_advanced_heap_walk(tag_map, _visit_stack, user_data, callbacks);
2777 }
2778
2779 VM_HeapWalkOperation::~VM_HeapWalkOperation() {
2780 if (_following_object_refs) {
2781 assert(_visit_stack != NULL, "checking");
2782 delete _visit_stack;
2783 _visit_stack = NULL;
2784 }
2785 }
2786
2787 // an array references its class and has a reference to
2788 // each element in the array
2789 inline bool VM_HeapWalkOperation::iterate_over_array(oop o) {
2790 objArrayOop array = objArrayOop(o);
2791
2792 // array reference to its class
2793 oop mirror = ObjArrayKlass::cast(array->klass())->java_mirror();
2794 if (!CallbackInvoker::report_class_reference(o, mirror)) {
2795 return false;
2796 }
2797
2798 // iterate over the array and report each reference to a
2799 // non-null element
2800 for (int index=0; index<array->length(); index++) {
2801 oop elem = array->obj_at(index);
2802 if (elem == NULL) {
2803 continue;
2804 }
2805
2806 // report the array reference o[index] = elem
2807 if (!CallbackInvoker::report_array_element_reference(o, elem, index)) {
2808 return false;
2809 }
2810 }
2811 return true;
2812 }
2813
2814 // a type array references its class
2815 inline bool VM_HeapWalkOperation::iterate_over_type_array(oop o) {
2816 Klass* k = o->klass();
2817 oop mirror = k->java_mirror();
2818 if (!CallbackInvoker::report_class_reference(o, mirror)) {
2819 return false;
2820 }
2821
2822 // report the array contents if required
2823 if (is_reporting_primitive_array_values()) {
2824 if (!CallbackInvoker::report_primitive_array_values(o)) {
2825 return false;
2826 }
2827 }
2828 return true;
2829 }
2830
2831 #ifdef ASSERT
2832 // verify that a static oop field is in range
2833 static inline bool verify_static_oop(InstanceKlass* ik,
2834 oop mirror, int offset) {
2835 address obj_p = (address)mirror + offset;
2836 address start = (address)InstanceMirrorKlass::start_of_static_fields(mirror);
2837 address end = start + (java_lang_Class::static_oop_field_count(mirror) * heapOopSize);
2838 assert(end >= start, "sanity check");
2839
2840 if (obj_p >= start && obj_p < end) {
2841 return true;
2842 } else {
2843 return false;
2844 }
2845 }
2846 #endif // #ifdef ASSERT
2847
2848 // a class references its super class, interfaces, class loader, ...
2849 // and finally its static fields
2850 inline bool VM_HeapWalkOperation::iterate_over_class(oop java_class) {
2851 int i;
2852 Klass* klass = java_lang_Class::as_Klass(java_class);
2853
2854 if (klass->is_instance_klass()) {
2855 InstanceKlass* ik = InstanceKlass::cast(klass);
2856
2857 // Ignore the class if it hasn't been initialized yet
2858 if (!ik->is_linked()) {
2859 return true;
2860 }
2861
2862 // get the java mirror
2863 oop mirror = klass->java_mirror();
2864
2865 // super (only if something more interesting than java.lang.Object)
2866 Klass* java_super = ik->java_super();
2867 if (java_super != NULL && java_super != SystemDictionary::Object_klass()) {
2868 oop super = java_super->java_mirror();
2869 if (!CallbackInvoker::report_superclass_reference(mirror, super)) {
2870 return false;
2871 }
2872 }
2873
2874 // class loader
2875 oop cl = ik->class_loader();
2876 if (cl != NULL) {
2877 if (!CallbackInvoker::report_class_loader_reference(mirror, cl)) {
2878 return false;
2879 }
2880 }
2881
2882 // protection domain
2883 oop pd = ik->protection_domain();
2884 if (pd != NULL) {
2885 if (!CallbackInvoker::report_protection_domain_reference(mirror, pd)) {
2886 return false;
2887 }
2888 }
2889
2890 // signers
2891 oop signers = ik->signers();
2892 if (signers != NULL) {
2893 if (!CallbackInvoker::report_signers_reference(mirror, signers)) {
2894 return false;
2895 }
2896 }
2897
2898 // references from the constant pool
2899 {
2900 ConstantPool* pool = ik->constants();
2901 for (int i = 1; i < pool->length(); i++) {
2902 constantTag tag = pool->tag_at(i).value();
2903 if (tag.is_string() || tag.is_klass()) {
2904 oop entry;
2905 if (tag.is_string()) {
2906 entry = pool->resolved_string_at(i);
2907 // If the entry is non-null it is resolved.
2908 if (entry == NULL) continue;
2909 } else {
2910 entry = pool->resolved_klass_at(i)->java_mirror();
2911 }
2912 if (!CallbackInvoker::report_constant_pool_reference(mirror, entry, (jint)i)) {
2913 return false;
2914 }
2915 }
2916 }
2917 }
2918
2919 // interfaces
2920 // (These will already have been reported as references from the constant pool
2921 // but are specified by IterateOverReachableObjects and must be reported).
2922 Array<Klass*>* interfaces = ik->local_interfaces();
2923 for (i = 0; i < interfaces->length(); i++) {
2924 oop interf = ((Klass*)interfaces->at(i))->java_mirror();
2925 if (interf == NULL) {
2926 continue;
2927 }
2928 if (!CallbackInvoker::report_interface_reference(mirror, interf)) {
2929 return false;
2930 }
2931 }
2932
2933 // iterate over the static fields
2934
2935 ClassFieldMap* field_map = ClassFieldMap::create_map_of_static_fields(klass);
2936 for (i=0; i<field_map->field_count(); i++) {
2937 ClassFieldDescriptor* field = field_map->field_at(i);
2938 char type = field->field_type();
2939 if (!is_primitive_field_type(type)) {
2940 oop fld_o = mirror->obj_field(field->field_offset());
2941 assert(verify_static_oop(ik, mirror, field->field_offset()), "sanity check");
2942 if (fld_o != NULL) {
2943 int slot = field->field_index();
2944 if (!CallbackInvoker::report_static_field_reference(mirror, fld_o, slot)) {
2945 delete field_map;
2946 return false;
2947 }
2948 }
2949 } else {
2950 if (is_reporting_primitive_fields()) {
2951 address addr = (address)mirror + field->field_offset();
2952 int slot = field->field_index();
2953 if (!CallbackInvoker::report_primitive_static_field(mirror, slot, addr, type)) {
2954 delete field_map;
2955 return false;
2956 }
2957 }
2958 }
2959 }
2960 delete field_map;
2961
2962 return true;
2963 }
2964
2965 return true;
2966 }
2967
2968 // an object references a class and its instance fields
2969 // (static fields are ignored here as we report these as
2970 // references from the class).
2971 inline bool VM_HeapWalkOperation::iterate_over_object(oop o) {
2972 // reference to the class
2973 if (!CallbackInvoker::report_class_reference(o, o->klass()->java_mirror())) {
2974 return false;
2975 }
2976
2977 // iterate over instance fields
2978 ClassFieldMap* field_map = JvmtiCachedClassFieldMap::get_map_of_instance_fields(o);
2979 for (int i=0; i<field_map->field_count(); i++) {
2980 ClassFieldDescriptor* field = field_map->field_at(i);
2981 char type = field->field_type();
2982 if (!is_primitive_field_type(type)) {
2983 oop fld_o = o->obj_field(field->field_offset());
2984 // ignore any objects that aren't visible to profiler
2985 if (fld_o != NULL && ServiceUtil::visible_oop(fld_o)) {
2986 assert(Universe::heap()->is_in_reserved(fld_o), "unsafe code should not "
2987 "have references to Klass* anymore");
2988 int slot = field->field_index();
2989 if (!CallbackInvoker::report_field_reference(o, fld_o, slot)) {
2990 return false;
2991 }
2992 }
2993 } else {
2994 if (is_reporting_primitive_fields()) {
2995 // primitive instance field
2996 address addr = (address)o + field->field_offset();
2997 int slot = field->field_index();
2998 if (!CallbackInvoker::report_primitive_instance_field(o, slot, addr, type)) {
2999 return false;
3000 }
3001 }
3002 }
3003 }
3004
3005 // if the object is a java.lang.String
3006 if (is_reporting_string_values() &&
3007 o->klass() == SystemDictionary::String_klass()) {
3008 if (!CallbackInvoker::report_string_value(o)) {
3009 return false;
3010 }
3011 }
3012 return true;
3013 }
3014
3015
3016 // Collects all simple (non-stack) roots except for threads;
3017 // threads are handled in collect_stack_roots() as an optimization.
3018 // if there's a heap root callback provided then the callback is
3019 // invoked for each simple root.
3020 // if an object reference callback is provided then all simple
3021 // roots are pushed onto the marking stack so that they can be
3022 // processed later
3023 //
3024 inline bool VM_HeapWalkOperation::collect_simple_roots() {
3025 SimpleRootsClosure blk;
3026
3027 // JNI globals
3028 blk.set_kind(JVMTI_HEAP_REFERENCE_JNI_GLOBAL);
3029 JNIHandles::oops_do(&blk);
3030 if (blk.stopped()) {
3031 return false;
3032 }
3033
3034 // Preloaded classes and loader from the system dictionary
3035 blk.set_kind(JVMTI_HEAP_REFERENCE_SYSTEM_CLASS);
3036 SystemDictionary::always_strong_oops_do(&blk);
3037 ClassLoaderDataGraph::always_strong_oops_do(&blk, false);
3038 if (blk.stopped()) {
3039 return false;
3040 }
3041
3042 // Inflated monitors
3043 blk.set_kind(JVMTI_HEAP_REFERENCE_MONITOR);
3044 ObjectSynchronizer::oops_do(&blk);
3045 if (blk.stopped()) {
3046 return false;
3047 }
3048
3049 // threads are now handled in collect_stack_roots()
3050
3051 // Other kinds of roots maintained by HotSpot
3052 // Many of these won't be visible but others (such as instances of important
3053 // exceptions) will be visible.
3054 blk.set_kind(JVMTI_HEAP_REFERENCE_OTHER);
3055 Universe::oops_do(&blk);
3056
3057 // If there are any non-perm roots in the code cache, visit them.
3058 blk.set_kind(JVMTI_HEAP_REFERENCE_OTHER);
3059 CodeBlobToOopClosure look_in_blobs(&blk, !CodeBlobToOopClosure::FixRelocations);
3060 CodeCache::scavenge_root_nmethods_do(&look_in_blobs);
3061
3062 return true;
3063 }
3064
3065 // Walk the stack of a given thread and find all references (locals
3066 // and JNI calls) and report these as stack references
3067 inline bool VM_HeapWalkOperation::collect_stack_roots(JavaThread* java_thread,
3068 JNILocalRootsClosure* blk)
3069 {
3070 oop threadObj = java_thread->threadObj();
3071 assert(threadObj != NULL, "sanity check");
3072
3073 // only need to get the thread's tag once per thread
3074 jlong thread_tag = tag_for(_tag_map, threadObj);
3075
3076 // also need the thread id
3077 jlong tid = java_lang_Thread::thread_id(threadObj);
3078
3079
3080 if (java_thread->has_last_Java_frame()) {
3081
3082 // vframes are resource allocated
3083 Thread* current_thread = Thread::current();
3084 ResourceMark rm(current_thread);
3085 HandleMark hm(current_thread);
3086
3087 RegisterMap reg_map(java_thread);
3088 frame f = java_thread->last_frame();
3089 vframe* vf = vframe::new_vframe(&f, ®_map, java_thread);
3090
3091 bool is_top_frame = true;
3092 int depth = 0;
3093 frame* last_entry_frame = NULL;
3094
3095 while (vf != NULL) {
3096 if (vf->is_java_frame()) {
3097
3098 // java frame (interpreted, compiled, ...)
3099 javaVFrame *jvf = javaVFrame::cast(vf);
3100
3101 // the jmethodID
3102 jmethodID method = jvf->method()->jmethod_id();
3103
3104 if (!(jvf->method()->is_native())) {
3105 jlocation bci = (jlocation)jvf->bci();
3106 StackValueCollection* locals = jvf->locals();
3107 for (int slot=0; slot<locals->size(); slot++) {
3108 if (locals->at(slot)->type() == T_OBJECT) {
3109 oop o = locals->obj_at(slot)();
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, slot, o)) {
3117 return false;
3118 }
3119 }
3120 }
3121
3122 StackValueCollection* exprs = jvf->expressions();
3123 for (int index=0; index < exprs->size(); index++) {
3124 if (exprs->at(index)->type() == T_OBJECT) {
3125 oop o = exprs->obj_at(index)();
3126 if (o == NULL) {
3127 continue;
3128 }
3129
3130 // stack reference
3131 if (!CallbackInvoker::report_stack_ref_root(thread_tag, tid, depth, method,
3132 bci, locals->size() + index, o)) {
3133 return false;
3134 }
3135 }
3136 }
3137
3138 // Follow oops from compiled nmethod
3139 if (jvf->cb() != NULL && jvf->cb()->is_nmethod()) {
3140 blk->set_context(thread_tag, tid, depth, method);
3141 jvf->cb()->as_nmethod()->oops_do(blk);
3142 }
3143 } else {
3144 blk->set_context(thread_tag, tid, depth, method);
3145 if (is_top_frame) {
3146 // JNI locals for the top frame.
3147 java_thread->active_handles()->oops_do(blk);
3148 } else {
3149 if (last_entry_frame != NULL) {
3150 // JNI locals for the entry frame
3151 assert(last_entry_frame->is_entry_frame(), "checking");
3152 last_entry_frame->entry_frame_call_wrapper()->handles()->oops_do(blk);
3153 }
3154 }
3155 }
3156 last_entry_frame = NULL;
3157 depth++;
3158 } else {
3159 // externalVFrame - for an entry frame then we report the JNI locals
3160 // when we find the corresponding javaVFrame
3161 frame* fr = vf->frame_pointer();
3162 assert(fr != NULL, "sanity check");
3163 if (fr->is_entry_frame()) {
3164 last_entry_frame = fr;
3165 }
3166 }
3167
3168 vf = vf->sender();
3169 is_top_frame = false;
3170 }
3171 } else {
3172 // no last java frame but there may be JNI locals
3173 blk->set_context(thread_tag, tid, 0, (jmethodID)NULL);
3174 java_thread->active_handles()->oops_do(blk);
3175 }
3176 return true;
3177 }
3178
3179
3180 // Collects the simple roots for all threads and collects all
3181 // stack roots - for each thread it walks the execution
3182 // stack to find all references and local JNI refs.
3183 inline bool VM_HeapWalkOperation::collect_stack_roots() {
3184 JNILocalRootsClosure blk;
3185 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thread = jtiwh.next(); ) {
3186 oop threadObj = thread->threadObj();
3187 if (threadObj != NULL && !thread->is_exiting() && !thread->is_hidden_from_external_view()) {
3188 // Collect the simple root for this thread before we
3189 // collect its stack roots
3190 if (!CallbackInvoker::report_simple_root(JVMTI_HEAP_REFERENCE_THREAD,
3191 threadObj)) {
3192 return false;
3193 }
3194 if (!collect_stack_roots(thread, &blk)) {
3195 return false;
3196 }
3197 }
3198 }
3199 return true;
3200 }
3201
3202 // visit an object
3203 // first mark the object as visited
3204 // second get all the outbound references from this object (in other words, all
3205 // the objects referenced by this object).
3206 //
3207 bool VM_HeapWalkOperation::visit(oop o) {
3208 // mark object as visited
3209 assert(!ObjectMarker::visited(o), "can't visit same object more than once");
3210 ObjectMarker::mark(o);
3211
3212 // instance
3213 if (o->is_instance()) {
3214 if (o->klass() == SystemDictionary::Class_klass()) {
3215 if (!java_lang_Class::is_primitive(o)) {
3216 // a java.lang.Class
3217 return iterate_over_class(o);
3218 }
3219 } else {
3220 return iterate_over_object(o);
3221 }
3222 }
3223
3224 // object array
3225 if (o->is_objArray()) {
3226 return iterate_over_array(o);
3227 }
3228
3229 // type array
3230 if (o->is_typeArray()) {
3231 return iterate_over_type_array(o);
3232 }
3233
3234 return true;
3235 }
3236
3237 void VM_HeapWalkOperation::doit() {
3238 ResourceMark rm;
3239 ObjectMarkerController marker;
3240 ClassFieldMapCacheMark cm;
3241
3242 assert(visit_stack()->is_empty(), "visit stack must be empty");
3243
3244 // the heap walk starts with an initial object or the heap roots
3245 if (initial_object().is_null()) {
3246 // If either collect_stack_roots() or collect_simple_roots()
3247 // returns false at this point, then there are no mark bits
3248 // to reset.
3249 ObjectMarker::set_needs_reset(false);
3250
3251 // Calling collect_stack_roots() before collect_simple_roots()
3252 // can result in a big performance boost for an agent that is
3253 // focused on analyzing references in the thread stacks.
3254 if (!collect_stack_roots()) return;
3255
3256 if (!collect_simple_roots()) return;
3257
3258 // no early return so enable heap traversal to reset the mark bits
3259 ObjectMarker::set_needs_reset(true);
3260 } else {
3261 visit_stack()->push(initial_object()());
3262 }
3263
3264 // object references required
3265 if (is_following_references()) {
3266
3267 // visit each object until all reachable objects have been
3268 // visited or the callback asked to terminate the iteration.
3269 while (!visit_stack()->is_empty()) {
3270 oop o = visit_stack()->pop();
3271 if (!ObjectMarker::visited(o)) {
3272 if (!visit(o)) {
3273 break;
3274 }
3275 }
3276 }
3277 }
3278 }
3279
3280 // iterate over all objects that are reachable from a set of roots
3281 void JvmtiTagMap::iterate_over_reachable_objects(jvmtiHeapRootCallback heap_root_callback,
3282 jvmtiStackReferenceCallback stack_ref_callback,
3283 jvmtiObjectReferenceCallback object_ref_callback,
3284 const void* user_data) {
3285 MutexLocker ml(Heap_lock);
3286 BasicHeapWalkContext context(heap_root_callback, stack_ref_callback, object_ref_callback);
3287 VM_HeapWalkOperation op(this, Handle(), context, user_data);
3288 VMThread::execute(&op);
3289 }
3290
3291 // iterate over all objects that are reachable from a given object
3292 void JvmtiTagMap::iterate_over_objects_reachable_from_object(jobject object,
3293 jvmtiObjectReferenceCallback object_ref_callback,
3294 const void* user_data) {
3295 oop obj = JNIHandles::resolve(object);
3296 Handle initial_object(Thread::current(), obj);
3297
3298 MutexLocker ml(Heap_lock);
3299 BasicHeapWalkContext context(NULL, NULL, object_ref_callback);
3300 VM_HeapWalkOperation op(this, initial_object, context, user_data);
3301 VMThread::execute(&op);
3302 }
3303
3304 // follow references from an initial object or the GC roots
3305 void JvmtiTagMap::follow_references(jint heap_filter,
3306 Klass* klass,
3307 jobject object,
3308 const jvmtiHeapCallbacks* callbacks,
3309 const void* user_data)
3310 {
3311 oop obj = JNIHandles::resolve(object);
3312 Handle initial_object(Thread::current(), obj);
3313
3314 MutexLocker ml(Heap_lock);
3315 AdvancedHeapWalkContext context(heap_filter, klass, callbacks);
3316 VM_HeapWalkOperation op(this, initial_object, context, user_data);
3317 VMThread::execute(&op);
3318 }
3319
3320
3321 void JvmtiTagMap::weak_oops_do(BoolObjectClosure* is_alive, OopClosure* f) {
3322 // No locks during VM bring-up (0 threads) and no safepoints after main
3323 // thread creation and before VMThread creation (1 thread); initial GC
3324 // verification can happen in that window which gets to here.
3325 assert(Threads::number_of_threads() <= 1 ||
3326 SafepointSynchronize::is_at_safepoint(),
3327 "must be executed at a safepoint");
3328 if (JvmtiEnv::environments_might_exist()) {
3329 JvmtiEnvIterator it;
3330 for (JvmtiEnvBase* env = it.first(); env != NULL; env = it.next(env)) {
3331 JvmtiTagMap* tag_map = env->tag_map();
3332 if (tag_map != NULL && !tag_map->is_empty()) {
3333 tag_map->do_weak_oops(is_alive, f);
3334 }
3335 }
3336 }
3337 }
3338
3339 void JvmtiTagMap::do_weak_oops(BoolObjectClosure* is_alive, OopClosure* f) {
3340
3341 // does this environment have the OBJECT_FREE event enabled
3342 bool post_object_free = env()->is_enabled(JVMTI_EVENT_OBJECT_FREE);
3343
3344 // counters used for trace message
3345 int freed = 0;
3346 int moved = 0;
3347
3348 JvmtiTagHashmap* hashmap = this->hashmap();
3349
3350 // reenable sizing (if disabled)
3351 hashmap->set_resizing_enabled(true);
3352
3353 // if the hashmap is empty then we can skip it
3354 if (hashmap->_entry_count == 0) {
3355 return;
3356 }
3357
3358 // now iterate through each entry in the table
3359
3360 JvmtiTagHashmapEntry** table = hashmap->table();
3361 int size = hashmap->size();
3362
3363 JvmtiTagHashmapEntry* delayed_add = NULL;
3364
3365 for (int pos = 0; pos < size; ++pos) {
3366 JvmtiTagHashmapEntry* entry = table[pos];
3367 JvmtiTagHashmapEntry* prev = NULL;
3368
3369 while (entry != NULL) {
3370 JvmtiTagHashmapEntry* next = entry->next();
3371
3372 // has object been GC'ed
3373 if (!is_alive->do_object_b(entry->object_peek())) {
3374 // grab the tag
3375 jlong tag = entry->tag();
3376 guarantee(tag != 0, "checking");
3377
3378 // remove GC'ed entry from hashmap and return the
3379 // entry to the free list
3380 hashmap->remove(prev, pos, entry);
3381 destroy_entry(entry);
3382
3383 // post the event to the profiler
3384 if (post_object_free) {
3385 JvmtiExport::post_object_free(env(), tag);
3386 }
3387
3388 ++freed;
3389 } else {
3390 f->do_oop(entry->object_addr());
3391 oop new_oop = entry->object_peek();
3392
3393 // if the object has moved then re-hash it and move its
3394 // entry to its new location.
3395 unsigned int new_pos = JvmtiTagHashmap::hash(new_oop, size);
3396 if (new_pos != (unsigned int)pos) {
3397 if (prev == NULL) {
3398 table[pos] = next;
3399 } else {
3400 prev->set_next(next);
3401 }
3402 if (new_pos < (unsigned int)pos) {
3403 entry->set_next(table[new_pos]);
3404 table[new_pos] = entry;
3405 } else {
3406 // Delay adding this entry to it's new position as we'd end up
3407 // hitting it again during this iteration.
3408 entry->set_next(delayed_add);
3409 delayed_add = entry;
3410 }
3411 moved++;
3412 } else {
3413 // object didn't move
3414 prev = entry;
3415 }
3416 }
3417
3418 entry = next;
3419 }
3420 }
3421
3422 // Re-add all the entries which were kept aside
3423 while (delayed_add != NULL) {
3424 JvmtiTagHashmapEntry* next = delayed_add->next();
3425 unsigned int pos = JvmtiTagHashmap::hash(delayed_add->object_peek(), size);
3426 delayed_add->set_next(table[pos]);
3427 table[pos] = delayed_add;
3428 delayed_add = next;
3429 }
3430
3431 log_debug(jvmti, objecttagging)("(%d->%d, %d freed, %d total moves)",
3432 hashmap->_entry_count + freed, hashmap->_entry_count, freed, moved);
3433 }