1 /*
2 * Copyright (c) 2003, 2014, 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/symbolTable.hpp"
27 #include "classfile/systemDictionary.hpp"
28 #include "classfile/vmSymbols.hpp"
29 #include "code/codeCache.hpp"
30 #include "jvmtifiles/jvmtiEnv.hpp"
31 #include "oops/instanceMirrorKlass.hpp"
32 #include "oops/objArrayKlass.hpp"
33 #include "oops/oop.inline2.hpp"
34 #include "prims/jvmtiEventController.hpp"
35 #include "prims/jvmtiEventController.inline.hpp"
36 #include "prims/jvmtiExport.hpp"
37 #include "prims/jvmtiImpl.hpp"
38 #include "prims/jvmtiTagMap.hpp"
39 #include "runtime/biasedLocking.hpp"
40 #include "runtime/javaCalls.hpp"
41 #include "runtime/jniHandles.hpp"
42 #include "runtime/mutex.hpp"
43 #include "runtime/mutexLocker.hpp"
44 #include "runtime/reflectionUtils.hpp"
45 #include "runtime/vframe.hpp"
46 #include "runtime/vmThread.hpp"
47 #include "runtime/vm_operations.hpp"
48 #include "services/serviceUtil.hpp"
49 #include "utilities/macros.hpp"
50 #if INCLUDE_ALL_GCS
51 #include "gc_implementation/parallelScavenge/parallelScavengeHeap.hpp"
52 #endif // INCLUDE_ALL_GCS
53
54 // JvmtiTagHashmapEntry
55 //
56 // Each entry encapsulates a reference to the tagged object
57 // and the tag value. In addition an entry includes a next pointer which
58 // is used to chain entries together.
59
60 class JvmtiTagHashmapEntry : public CHeapObj<mtInternal> {
61 private:
62 friend class JvmtiTagMap;
63
64 oop _object; // tagged object
65 jlong _tag; // the tag
66 JvmtiTagHashmapEntry* _next; // next on the list
67
68 inline void init(oop object, jlong tag) {
69 _object = object;
70 _tag = tag;
71 _next = NULL;
72 }
73
74 // constructor
75 JvmtiTagHashmapEntry(oop object, jlong tag) { init(object, tag); }
76
77 public:
78
79 // accessor methods
80 inline oop object() const { return _object; }
81 inline oop* object_addr() { return &_object; }
82 inline jlong tag() const { return _tag; }
83
84 inline void set_tag(jlong tag) {
85 assert(tag != 0, "can't be zero");
86 _tag = tag;
87 }
88
89 inline JvmtiTagHashmapEntry* next() const { return _next; }
90 inline void set_next(JvmtiTagHashmapEntry* next) { _next = next; }
91 };
92
93
94 // JvmtiTagHashmap
95 //
96 // A hashmap is essentially a table of pointers to entries. Entries
97 // are hashed to a location, or position in the table, and then
98 // chained from that location. The "key" for hashing is address of
99 // the object, or oop. The "value" is the tag value.
100 //
101 // A hashmap maintains a count of the number entries in the hashmap
102 // and resizes if the number of entries exceeds a given threshold.
103 // The threshold is specified as a percentage of the size - for
104 // example a threshold of 0.75 will trigger the hashmap to resize
105 // if the number of entries is >75% of table size.
106 //
107 // A hashmap provides functions for adding, removing, and finding
108 // entries. It also provides a function to iterate over all entries
109 // in the hashmap.
110
111 class JvmtiTagHashmap : public CHeapObj<mtInternal> {
112 private:
113 friend class JvmtiTagMap;
114
115 enum {
116 small_trace_threshold = 10000, // threshold for tracing
117 medium_trace_threshold = 100000,
118 large_trace_threshold = 1000000,
119 initial_trace_threshold = small_trace_threshold
120 };
121
122 static int _sizes[]; // array of possible hashmap sizes
123 int _size; // actual size of the table
124 int _size_index; // index into size table
125
126 int _entry_count; // number of entries in the hashmap
127
128 float _load_factor; // load factor as a % of the size
129 int _resize_threshold; // computed threshold to trigger resizing.
130 bool _resizing_enabled; // indicates if hashmap can resize
131
132 int _trace_threshold; // threshold for trace messages
133
134 JvmtiTagHashmapEntry** _table; // the table of entries.
135
136 // private accessors
137 int resize_threshold() const { return _resize_threshold; }
138 int trace_threshold() const { return _trace_threshold; }
139
140 // initialize the hashmap
141 void init(int size_index=0, float load_factor=4.0f) {
142 int initial_size = _sizes[size_index];
143 _size_index = size_index;
144 _size = initial_size;
145 _entry_count = 0;
146 if (TraceJVMTIObjectTagging) {
147 _trace_threshold = initial_trace_threshold;
148 } else {
149 _trace_threshold = -1;
150 }
151 _load_factor = load_factor;
152 _resize_threshold = (int)(_load_factor * _size);
153 _resizing_enabled = true;
154 size_t s = initial_size * sizeof(JvmtiTagHashmapEntry*);
155 _table = (JvmtiTagHashmapEntry**)os::malloc(s, mtInternal);
156 if (_table == NULL) {
157 vm_exit_out_of_memory(s, OOM_MALLOC_ERROR,
158 "unable to allocate initial hashtable for jvmti object tags");
159 }
160 for (int i=0; i<initial_size; i++) {
161 _table[i] = NULL;
162 }
163 }
164
165 // hash a given key (oop) with the specified size
166 static unsigned int hash(oop key, int size) {
167 // shift right to get better distribution (as these bits will be zero
168 // with aligned addresses)
169 unsigned int addr = (unsigned int)(cast_from_oop<intptr_t>(key));
170 #ifdef _LP64
171 return (addr >> 3) % size;
172 #else
173 return (addr >> 2) % size;
174 #endif
175 }
176
177 // hash a given key (oop)
178 unsigned int hash(oop key) {
179 return hash(key, _size);
180 }
181
182 // resize the hashmap - allocates a large table and re-hashes
183 // all entries into the new table.
184 void resize() {
185 int new_size_index = _size_index+1;
186 int new_size = _sizes[new_size_index];
187 if (new_size < 0) {
188 // hashmap already at maximum capacity
189 return;
190 }
191
192 // allocate new table
193 size_t s = new_size * sizeof(JvmtiTagHashmapEntry*);
194 JvmtiTagHashmapEntry** new_table = (JvmtiTagHashmapEntry**)os::malloc(s, mtInternal);
195 if (new_table == NULL) {
196 warning("unable to allocate larger hashtable for jvmti object tags");
197 set_resizing_enabled(false);
198 return;
199 }
200
201 // initialize new table
202 int i;
203 for (i=0; i<new_size; i++) {
204 new_table[i] = NULL;
205 }
206
207 // rehash all entries into the new table
208 for (i=0; i<_size; i++) {
209 JvmtiTagHashmapEntry* entry = _table[i];
210 while (entry != NULL) {
211 JvmtiTagHashmapEntry* next = entry->next();
212 oop key = entry->object();
213 assert(key != NULL, "jni weak reference cleared!!");
214 unsigned int h = hash(key, new_size);
215 JvmtiTagHashmapEntry* anchor = new_table[h];
216 if (anchor == NULL) {
217 new_table[h] = entry;
218 entry->set_next(NULL);
219 } else {
220 entry->set_next(anchor);
221 new_table[h] = entry;
222 }
223 entry = next;
224 }
225 }
226
227 // free old table and update settings.
228 os::free((void*)_table);
229 _table = new_table;
230 _size_index = new_size_index;
231 _size = new_size;
232
233 // compute new resize threshold
234 _resize_threshold = (int)(_load_factor * _size);
235 }
236
237
238 // internal remove function - remove an entry at a given position in the
239 // table.
240 inline void remove(JvmtiTagHashmapEntry* prev, int pos, JvmtiTagHashmapEntry* entry) {
241 assert(pos >= 0 && pos < _size, "out of range");
242 if (prev == NULL) {
243 _table[pos] = entry->next();
244 } else {
245 prev->set_next(entry->next());
246 }
247 assert(_entry_count > 0, "checking");
248 _entry_count--;
249 }
250
251 // resizing switch
252 bool is_resizing_enabled() const { return _resizing_enabled; }
253 void set_resizing_enabled(bool enable) { _resizing_enabled = enable; }
254
255 // debugging
256 void print_memory_usage();
257 void compute_next_trace_threshold();
258
259 public:
260
261 // create a JvmtiTagHashmap of a preferred size and optionally a load factor.
262 // The preferred size is rounded down to an actual size.
263 JvmtiTagHashmap(int size, float load_factor=0.0f) {
264 int i=0;
265 while (_sizes[i] < size) {
266 if (_sizes[i] < 0) {
267 assert(i > 0, "sanity check");
268 i--;
269 break;
270 }
271 i++;
272 }
273
274 // if a load factor is specified then use it, otherwise use default
275 if (load_factor > 0.01f) {
276 init(i, load_factor);
277 } else {
278 init(i);
279 }
280 }
281
282 // create a JvmtiTagHashmap with default settings
283 JvmtiTagHashmap() {
284 init();
285 }
286
287 // release table when JvmtiTagHashmap destroyed
288 ~JvmtiTagHashmap() {
289 if (_table != NULL) {
290 os::free((void*)_table);
291 _table = NULL;
292 }
293 }
294
295 // accessors
296 int size() const { return _size; }
297 JvmtiTagHashmapEntry** table() const { return _table; }
298 int entry_count() const { return _entry_count; }
299
300 // find an entry in the hashmap, returns NULL if not found.
301 inline JvmtiTagHashmapEntry* find(oop key) {
302 unsigned int h = hash(key);
303 JvmtiTagHashmapEntry* entry = _table[h];
304 while (entry != NULL) {
305 if (entry->object() == key) {
306 return entry;
307 }
308 entry = entry->next();
309 }
310 return NULL;
311 }
312
313
314 // add a new entry to hashmap
315 inline void add(oop key, JvmtiTagHashmapEntry* entry) {
316 assert(key != NULL, "checking");
317 assert(find(key) == NULL, "duplicate detected");
318 unsigned int h = hash(key);
319 JvmtiTagHashmapEntry* anchor = _table[h];
320 if (anchor == NULL) {
321 _table[h] = entry;
322 entry->set_next(NULL);
323 } else {
324 entry->set_next(anchor);
325 _table[h] = entry;
326 }
327
328 _entry_count++;
329 if (trace_threshold() > 0 && entry_count() >= trace_threshold()) {
330 assert(TraceJVMTIObjectTagging, "should only get here when tracing");
331 print_memory_usage();
332 compute_next_trace_threshold();
333 }
334
335 // if the number of entries exceed the threshold then resize
336 if (entry_count() > resize_threshold() && is_resizing_enabled()) {
337 resize();
338 }
339 }
340
341 // remove an entry with the given key.
342 inline JvmtiTagHashmapEntry* remove(oop key) {
343 unsigned int h = hash(key);
344 JvmtiTagHashmapEntry* entry = _table[h];
345 JvmtiTagHashmapEntry* prev = NULL;
346 while (entry != NULL) {
347 if (key == entry->object()) {
348 break;
349 }
350 prev = entry;
351 entry = entry->next();
352 }
353 if (entry != NULL) {
354 remove(prev, h, entry);
355 }
356 return entry;
357 }
358
359 // iterate over all entries in the hashmap
360 void entry_iterate(JvmtiTagHashmapEntryClosure* closure);
361 };
362
363 // possible hashmap sizes - odd primes that roughly double in size.
364 // To avoid excessive resizing the odd primes from 4801-76831 and
365 // 76831-307261 have been removed. The list must be terminated by -1.
366 int JvmtiTagHashmap::_sizes[] = { 4801, 76831, 307261, 614563, 1228891,
367 2457733, 4915219, 9830479, 19660831, 39321619, 78643219, -1 };
368
369
370 // A supporting class for iterating over all entries in Hashmap
371 class JvmtiTagHashmapEntryClosure {
372 public:
373 virtual void do_entry(JvmtiTagHashmapEntry* entry) = 0;
374 };
375
376
377 // iterate over all entries in the hashmap
378 void JvmtiTagHashmap::entry_iterate(JvmtiTagHashmapEntryClosure* closure) {
379 for (int i=0; i<_size; i++) {
380 JvmtiTagHashmapEntry* entry = _table[i];
381 JvmtiTagHashmapEntry* prev = NULL;
382 while (entry != NULL) {
383 // obtain the next entry before invoking do_entry - this is
384 // necessary because do_entry may remove the entry from the
385 // hashmap.
386 JvmtiTagHashmapEntry* next = entry->next();
387 closure->do_entry(entry);
388 entry = next;
389 }
390 }
391 }
392
393 // debugging
394 void JvmtiTagHashmap::print_memory_usage() {
395 intptr_t p = (intptr_t)this;
396 tty->print("[JvmtiTagHashmap @ " INTPTR_FORMAT, p);
397
398 // table + entries in KB
399 int hashmap_usage = (size()*sizeof(JvmtiTagHashmapEntry*) +
400 entry_count()*sizeof(JvmtiTagHashmapEntry))/K;
401
402 int weak_globals_usage = (int)(JNIHandles::weak_global_handle_memory_usage()/K);
403 tty->print_cr(", %d entries (%d KB) <JNI weak globals: %d KB>]",
404 entry_count(), hashmap_usage, weak_globals_usage);
405 }
406
407 // compute threshold for the next trace message
408 void JvmtiTagHashmap::compute_next_trace_threshold() {
409 if (trace_threshold() < medium_trace_threshold) {
410 _trace_threshold += small_trace_threshold;
411 } else {
412 if (trace_threshold() < large_trace_threshold) {
413 _trace_threshold += medium_trace_threshold;
414 } else {
415 _trace_threshold += large_trace_threshold;
416 }
417 }
418 }
419
420 // create a JvmtiTagMap
421 JvmtiTagMap::JvmtiTagMap(JvmtiEnv* env) :
422 _env(env),
423 _lock(Mutex::nonleaf+2, "JvmtiTagMap._lock", false),
424 _free_entries(NULL),
425 _free_entries_count(0)
426 {
427 assert(JvmtiThreadState_lock->is_locked(), "sanity check");
428 assert(((JvmtiEnvBase *)env)->tag_map() == NULL, "tag map already exists for environment");
429
430 _hashmap = new JvmtiTagHashmap();
431
432 // finally add us to the environment
433 ((JvmtiEnvBase *)env)->set_tag_map(this);
434 }
435
436
437 // destroy a JvmtiTagMap
438 JvmtiTagMap::~JvmtiTagMap() {
439
440 // no lock acquired as we assume the enclosing environment is
441 // also being destroryed.
442 ((JvmtiEnvBase *)_env)->set_tag_map(NULL);
443
444 JvmtiTagHashmapEntry** table = _hashmap->table();
445 for (int j = 0; j < _hashmap->size(); j++) {
446 JvmtiTagHashmapEntry* entry = table[j];
447 while (entry != NULL) {
448 JvmtiTagHashmapEntry* next = entry->next();
449 delete entry;
450 entry = next;
451 }
452 }
453
454 // finally destroy the hashmap
455 delete _hashmap;
456 _hashmap = NULL;
457
458 // remove any entries on the free list
459 JvmtiTagHashmapEntry* entry = _free_entries;
460 while (entry != NULL) {
461 JvmtiTagHashmapEntry* next = entry->next();
462 delete entry;
463 entry = next;
464 }
465 _free_entries = NULL;
466 }
467
468 // create a hashmap entry
469 // - if there's an entry on the (per-environment) free list then this
470 // is returned. Otherwise an new entry is allocated.
471 JvmtiTagHashmapEntry* JvmtiTagMap::create_entry(oop ref, jlong tag) {
472 assert(Thread::current()->is_VM_thread() || is_locked(), "checking");
473 JvmtiTagHashmapEntry* entry;
474 if (_free_entries == NULL) {
475 entry = new JvmtiTagHashmapEntry(ref, tag);
476 } else {
477 assert(_free_entries_count > 0, "mismatched _free_entries_count");
478 _free_entries_count--;
479 entry = _free_entries;
480 _free_entries = entry->next();
481 entry->init(ref, tag);
482 }
483 return entry;
484 }
485
486 // destroy an entry by returning it to the free list
487 void JvmtiTagMap::destroy_entry(JvmtiTagHashmapEntry* entry) {
488 assert(SafepointSynchronize::is_at_safepoint() || is_locked(), "checking");
489 // limit the size of the free list
490 if (_free_entries_count >= max_free_entries) {
491 delete entry;
492 } else {
493 entry->set_next(_free_entries);
494 _free_entries = entry;
495 _free_entries_count++;
496 }
497 }
498
499 // returns the tag map for the given environments. If the tag map
500 // doesn't exist then it is created.
501 JvmtiTagMap* JvmtiTagMap::tag_map_for(JvmtiEnv* env) {
502 JvmtiTagMap* tag_map = ((JvmtiEnvBase*)env)->tag_map();
503 if (tag_map == NULL) {
504 MutexLocker mu(JvmtiThreadState_lock);
505 tag_map = ((JvmtiEnvBase*)env)->tag_map();
506 if (tag_map == NULL) {
507 tag_map = new JvmtiTagMap(env);
508 }
509 } else {
510 CHECK_UNHANDLED_OOPS_ONLY(Thread::current()->clear_unhandled_oops());
511 }
512 return tag_map;
513 }
514
515 // iterate over all entries in the tag map.
516 void JvmtiTagMap::entry_iterate(JvmtiTagHashmapEntryClosure* closure) {
517 hashmap()->entry_iterate(closure);
518 }
519
520 // returns true if the hashmaps are empty
521 bool JvmtiTagMap::is_empty() {
522 assert(SafepointSynchronize::is_at_safepoint() || is_locked(), "checking");
523 return hashmap()->entry_count() == 0;
524 }
525
526
527 // Return the tag value for an object, or 0 if the object is
528 // not tagged
529 //
530 static inline jlong tag_for(JvmtiTagMap* tag_map, oop o) {
531 JvmtiTagHashmapEntry* entry = tag_map->hashmap()->find(o);
532 if (entry == NULL) {
533 return 0;
534 } else {
535 return entry->tag();
536 }
537 }
538
539
540 // A CallbackWrapper is a support class for querying and tagging an object
541 // around a callback to a profiler. The constructor does pre-callback
542 // work to get the tag value, klass tag value, ... and the destructor
543 // does the post-callback work of tagging or untagging the object.
544 //
545 // {
546 // CallbackWrapper wrapper(tag_map, o);
547 //
548 // (*callback)(wrapper.klass_tag(), wrapper.obj_size(), wrapper.obj_tag_p(), ...)
549 //
550 // } // wrapper goes out of scope here which results in the destructor
551 // checking to see if the object has been tagged, untagged, or the
552 // tag value has changed.
553 //
554 class CallbackWrapper : public StackObj {
555 private:
556 JvmtiTagMap* _tag_map;
557 JvmtiTagHashmap* _hashmap;
558 JvmtiTagHashmapEntry* _entry;
559 oop _o;
560 jlong _obj_size;
561 jlong _obj_tag;
562 jlong _klass_tag;
563
564 protected:
565 JvmtiTagMap* tag_map() const { return _tag_map; }
566
567 // invoked post-callback to tag, untag, or update the tag of an object
568 void inline post_callback_tag_update(oop o, JvmtiTagHashmap* hashmap,
569 JvmtiTagHashmapEntry* entry, jlong obj_tag);
570 public:
571 CallbackWrapper(JvmtiTagMap* tag_map, oop o) {
572 assert(Thread::current()->is_VM_thread() || tag_map->is_locked(),
573 "MT unsafe or must be VM thread");
574
575 // object to tag
576 _o = o;
577
578 // object size
579 _obj_size = (jlong)_o->size() * wordSize;
580
581 // record the context
582 _tag_map = tag_map;
583 _hashmap = tag_map->hashmap();
584 _entry = _hashmap->find(_o);
585
586 // get object tag
587 _obj_tag = (_entry == NULL) ? 0 : _entry->tag();
588
589 // get the class and the class's tag value
590 assert(SystemDictionary::Class_klass()->oop_is_instanceMirror(), "Is not?");
591
592 _klass_tag = tag_for(tag_map, _o->klass()->java_mirror());
593 }
594
595 ~CallbackWrapper() {
596 post_callback_tag_update(_o, _hashmap, _entry, _obj_tag);
597 }
598
599 inline jlong* obj_tag_p() { return &_obj_tag; }
600 inline jlong obj_size() const { return _obj_size; }
601 inline jlong obj_tag() const { return _obj_tag; }
602 inline jlong klass_tag() const { return _klass_tag; }
603 };
604
605
606
607 // callback post-callback to tag, untag, or update the tag of an object
608 void inline CallbackWrapper::post_callback_tag_update(oop o,
609 JvmtiTagHashmap* hashmap,
610 JvmtiTagHashmapEntry* entry,
611 jlong obj_tag) {
612 if (entry == NULL) {
613 if (obj_tag != 0) {
614 // callback has tagged the object
615 assert(Thread::current()->is_VM_thread(), "must be VMThread");
616 entry = tag_map()->create_entry(o, obj_tag);
617 hashmap->add(o, entry);
618 }
619 } else {
620 // object was previously tagged - the callback may have untagged
621 // the object or changed the tag value
622 if (obj_tag == 0) {
623
624 JvmtiTagHashmapEntry* entry_removed = hashmap->remove(o);
625 assert(entry_removed == entry, "checking");
626 tag_map()->destroy_entry(entry);
627
628 } else {
629 if (obj_tag != entry->tag()) {
630 entry->set_tag(obj_tag);
631 }
632 }
633 }
634 }
635
636 // An extended CallbackWrapper used when reporting an object reference
637 // to the agent.
638 //
639 // {
640 // TwoOopCallbackWrapper wrapper(tag_map, referrer, o);
641 //
642 // (*callback)(wrapper.klass_tag(),
643 // wrapper.obj_size(),
644 // wrapper.obj_tag_p()
645 // wrapper.referrer_tag_p(), ...)
646 //
647 // } // wrapper goes out of scope here which results in the destructor
648 // checking to see if the referrer object has been tagged, untagged,
649 // or the tag value has changed.
650 //
651 class TwoOopCallbackWrapper : public CallbackWrapper {
652 private:
653 bool _is_reference_to_self;
654 JvmtiTagHashmap* _referrer_hashmap;
655 JvmtiTagHashmapEntry* _referrer_entry;
656 oop _referrer;
657 jlong _referrer_obj_tag;
658 jlong _referrer_klass_tag;
659 jlong* _referrer_tag_p;
660
661 bool is_reference_to_self() const { return _is_reference_to_self; }
662
663 public:
664 TwoOopCallbackWrapper(JvmtiTagMap* tag_map, oop referrer, oop o) :
665 CallbackWrapper(tag_map, o)
666 {
667 // self reference needs to be handled in a special way
668 _is_reference_to_self = (referrer == o);
669
670 if (_is_reference_to_self) {
671 _referrer_klass_tag = klass_tag();
672 _referrer_tag_p = obj_tag_p();
673 } else {
674 _referrer = referrer;
675 // record the context
676 _referrer_hashmap = tag_map->hashmap();
677 _referrer_entry = _referrer_hashmap->find(_referrer);
678
679 // get object tag
680 _referrer_obj_tag = (_referrer_entry == NULL) ? 0 : _referrer_entry->tag();
681 _referrer_tag_p = &_referrer_obj_tag;
682
683 // get referrer class tag.
684 _referrer_klass_tag = tag_for(tag_map, _referrer->klass()->java_mirror());
685 }
686 }
687
688 ~TwoOopCallbackWrapper() {
689 if (!is_reference_to_self()){
690 post_callback_tag_update(_referrer,
691 _referrer_hashmap,
692 _referrer_entry,
693 _referrer_obj_tag);
694 }
695 }
696
697 // address of referrer tag
698 // (for a self reference this will return the same thing as obj_tag_p())
699 inline jlong* referrer_tag_p() { return _referrer_tag_p; }
700
701 // referrer's class tag
702 inline jlong referrer_klass_tag() { return _referrer_klass_tag; }
703 };
704
705 // tag an object
706 //
707 // This function is performance critical. If many threads attempt to tag objects
708 // around the same time then it's possible that the Mutex associated with the
709 // tag map will be a hot lock.
710 void JvmtiTagMap::set_tag(jobject object, jlong tag) {
711 MutexLocker ml(lock());
712
713 // resolve the object
714 oop o = JNIHandles::resolve_non_null(object);
715
716 // see if the object is already tagged
717 JvmtiTagHashmap* hashmap = _hashmap;
718 JvmtiTagHashmapEntry* entry = hashmap->find(o);
719
720 // if the object is not already tagged then we tag it
721 if (entry == NULL) {
722 if (tag != 0) {
723 entry = create_entry(o, tag);
724 hashmap->add(o, entry);
725 } else {
726 // no-op
727 }
728 } else {
729 // if the object is already tagged then we either update
730 // the tag (if a new tag value has been provided)
731 // or remove the object if the new tag value is 0.
732 if (tag == 0) {
733 hashmap->remove(o);
734 destroy_entry(entry);
735 } else {
736 entry->set_tag(tag);
737 }
738 }
739 }
740
741 // get the tag for an object
742 jlong JvmtiTagMap::get_tag(jobject object) {
743 MutexLocker ml(lock());
744
745 // resolve the object
746 oop o = JNIHandles::resolve_non_null(object);
747
748 return tag_for(this, o);
749 }
750
751
752 // Helper class used to describe the static or instance fields of a class.
753 // For each field it holds the field index (as defined by the JVMTI specification),
754 // the field type, and the offset.
755
756 class ClassFieldDescriptor: public CHeapObj<mtInternal> {
757 private:
758 int _field_index;
759 int _field_offset;
760 char _field_type;
761 public:
762 ClassFieldDescriptor(int index, char type, int offset) :
763 _field_index(index), _field_type(type), _field_offset(offset) {
764 }
765 int field_index() const { return _field_index; }
766 char field_type() const { return _field_type; }
767 int field_offset() const { return _field_offset; }
768 };
769
770 class ClassFieldMap: public CHeapObj<mtInternal> {
771 private:
772 enum {
773 initial_field_count = 5
774 };
775
776 // list of field descriptors
777 GrowableArray<ClassFieldDescriptor*>* _fields;
778
779 // constructor
780 ClassFieldMap();
781
782 // add a field
783 void add(int index, char type, int offset);
784
785 // returns the field count for the given class
786 static int compute_field_count(instanceKlassHandle ikh);
787
788 public:
789 ~ClassFieldMap();
790
791 // access
792 int field_count() { return _fields->length(); }
793 ClassFieldDescriptor* field_at(int i) { return _fields->at(i); }
794
795 // functions to create maps of static or instance fields
796 static ClassFieldMap* create_map_of_static_fields(Klass* k);
797 static ClassFieldMap* create_map_of_instance_fields(oop obj);
798 };
799
800 ClassFieldMap::ClassFieldMap() {
801 _fields = new (ResourceObj::C_HEAP, mtInternal)
802 GrowableArray<ClassFieldDescriptor*>(initial_field_count, true);
803 }
804
805 ClassFieldMap::~ClassFieldMap() {
806 for (int i=0; i<_fields->length(); i++) {
807 delete _fields->at(i);
808 }
809 delete _fields;
810 }
811
812 void ClassFieldMap::add(int index, char type, int offset) {
813 ClassFieldDescriptor* field = new ClassFieldDescriptor(index, type, offset);
814 _fields->append(field);
815 }
816
817 // Returns a heap allocated ClassFieldMap to describe the static fields
818 // of the given class.
819 //
820 ClassFieldMap* ClassFieldMap::create_map_of_static_fields(Klass* k) {
821 HandleMark hm;
822 instanceKlassHandle ikh = instanceKlassHandle(Thread::current(), k);
823
824 // create the field map
825 ClassFieldMap* field_map = new ClassFieldMap();
826
827 FilteredFieldStream f(ikh, false, false);
828 int max_field_index = f.field_count()-1;
829
830 int index = 0;
831 for (FilteredFieldStream fld(ikh, true, true); !fld.eos(); fld.next(), index++) {
832 // ignore instance fields
833 if (!fld.access_flags().is_static()) {
834 continue;
835 }
836 field_map->add(max_field_index - index, fld.signature()->byte_at(0), fld.offset());
837 }
838 return field_map;
839 }
840
841 // Returns a heap allocated ClassFieldMap to describe the instance fields
842 // of the given class. All instance fields are included (this means public
843 // and private fields declared in superclasses and superinterfaces too).
844 //
845 ClassFieldMap* ClassFieldMap::create_map_of_instance_fields(oop obj) {
846 HandleMark hm;
847 instanceKlassHandle ikh = instanceKlassHandle(Thread::current(), obj->klass());
848
849 // create the field map
850 ClassFieldMap* field_map = new ClassFieldMap();
851
852 FilteredFieldStream f(ikh, false, false);
853
854 int max_field_index = f.field_count()-1;
855
856 int index = 0;
857 for (FilteredFieldStream fld(ikh, false, false); !fld.eos(); fld.next(), index++) {
858 // ignore static fields
859 if (fld.access_flags().is_static()) {
860 continue;
861 }
862 field_map->add(max_field_index - index, fld.signature()->byte_at(0), fld.offset());
863 }
864
865 return field_map;
866 }
867
868 // Helper class used to cache a ClassFileMap for the instance fields of
869 // a cache. A JvmtiCachedClassFieldMap can be cached by an InstanceKlass during
870 // heap iteration and avoid creating a field map for each object in the heap
871 // (only need to create the map when the first instance of a class is encountered).
872 //
873 class JvmtiCachedClassFieldMap : public CHeapObj<mtInternal> {
874 private:
875 enum {
876 initial_class_count = 200
877 };
878 ClassFieldMap* _field_map;
879
880 ClassFieldMap* field_map() const { return _field_map; }
881
882 JvmtiCachedClassFieldMap(ClassFieldMap* field_map);
883 ~JvmtiCachedClassFieldMap();
884
885 static GrowableArray<InstanceKlass*>* _class_list;
886 static void add_to_class_list(InstanceKlass* ik);
887
888 public:
889 // returns the field map for a given object (returning map cached
890 // by InstanceKlass if possible
891 static ClassFieldMap* get_map_of_instance_fields(oop obj);
892
893 // removes the field map from all instanceKlasses - should be
894 // called before VM operation completes
895 static void clear_cache();
896
897 // returns the number of ClassFieldMap cached by instanceKlasses
898 static int cached_field_map_count();
899 };
900
901 GrowableArray<InstanceKlass*>* JvmtiCachedClassFieldMap::_class_list;
902
903 JvmtiCachedClassFieldMap::JvmtiCachedClassFieldMap(ClassFieldMap* field_map) {
904 _field_map = field_map;
905 }
906
907 JvmtiCachedClassFieldMap::~JvmtiCachedClassFieldMap() {
908 if (_field_map != NULL) {
909 delete _field_map;
910 }
911 }
912
913 // Marker class to ensure that the class file map cache is only used in a defined
914 // scope.
915 class ClassFieldMapCacheMark : public StackObj {
916 private:
917 static bool _is_active;
918 public:
919 ClassFieldMapCacheMark() {
920 assert(Thread::current()->is_VM_thread(), "must be VMThread");
921 assert(JvmtiCachedClassFieldMap::cached_field_map_count() == 0, "cache not empty");
922 assert(!_is_active, "ClassFieldMapCacheMark cannot be nested");
923 _is_active = true;
924 }
925 ~ClassFieldMapCacheMark() {
926 JvmtiCachedClassFieldMap::clear_cache();
927 _is_active = false;
928 }
929 static bool is_active() { return _is_active; }
930 };
931
932 bool ClassFieldMapCacheMark::_is_active;
933
934
935 // record that the given InstanceKlass is caching a field map
936 void JvmtiCachedClassFieldMap::add_to_class_list(InstanceKlass* ik) {
937 if (_class_list == NULL) {
938 _class_list = new (ResourceObj::C_HEAP, mtInternal)
939 GrowableArray<InstanceKlass*>(initial_class_count, true);
940 }
941 _class_list->push(ik);
942 }
943
944 // returns the instance field map for the given object
945 // (returns field map cached by the InstanceKlass if possible)
946 ClassFieldMap* JvmtiCachedClassFieldMap::get_map_of_instance_fields(oop obj) {
947 assert(Thread::current()->is_VM_thread(), "must be VMThread");
948 assert(ClassFieldMapCacheMark::is_active(), "ClassFieldMapCacheMark not active");
949
950 Klass* k = obj->klass();
951 InstanceKlass* ik = InstanceKlass::cast(k);
952
953 // return cached map if possible
954 JvmtiCachedClassFieldMap* cached_map = ik->jvmti_cached_class_field_map();
955 if (cached_map != NULL) {
956 assert(cached_map->field_map() != NULL, "missing field list");
957 return cached_map->field_map();
958 } else {
959 ClassFieldMap* field_map = ClassFieldMap::create_map_of_instance_fields(obj);
960 cached_map = new JvmtiCachedClassFieldMap(field_map);
961 ik->set_jvmti_cached_class_field_map(cached_map);
962 add_to_class_list(ik);
963 return field_map;
964 }
965 }
966
967 // remove the fields maps cached from all instanceKlasses
968 void JvmtiCachedClassFieldMap::clear_cache() {
969 assert(Thread::current()->is_VM_thread(), "must be VMThread");
970 if (_class_list != NULL) {
971 for (int i = 0; i < _class_list->length(); i++) {
972 InstanceKlass* ik = _class_list->at(i);
973 JvmtiCachedClassFieldMap* cached_map = ik->jvmti_cached_class_field_map();
974 assert(cached_map != NULL, "should not be NULL");
975 ik->set_jvmti_cached_class_field_map(NULL);
976 delete cached_map; // deletes the encapsulated field map
977 }
978 delete _class_list;
979 _class_list = NULL;
980 }
981 }
982
983 // returns the number of ClassFieldMap cached by instanceKlasses
984 int JvmtiCachedClassFieldMap::cached_field_map_count() {
985 return (_class_list == NULL) ? 0 : _class_list->length();
986 }
987
988 // helper function to indicate if an object is filtered by its tag or class tag
989 static inline bool is_filtered_by_heap_filter(jlong obj_tag,
990 jlong klass_tag,
991 int heap_filter) {
992 // apply the heap filter
993 if (obj_tag != 0) {
994 // filter out tagged objects
995 if (heap_filter & JVMTI_HEAP_FILTER_TAGGED) return true;
996 } else {
997 // filter out untagged objects
998 if (heap_filter & JVMTI_HEAP_FILTER_UNTAGGED) return true;
999 }
1000 if (klass_tag != 0) {
1001 // filter out objects with tagged classes
1002 if (heap_filter & JVMTI_HEAP_FILTER_CLASS_TAGGED) return true;
1003 } else {
1004 // filter out objects with untagged classes.
1005 if (heap_filter & JVMTI_HEAP_FILTER_CLASS_UNTAGGED) return true;
1006 }
1007 return false;
1008 }
1009
1010 // helper function to indicate if an object is filtered by a klass filter
1011 static inline bool is_filtered_by_klass_filter(oop obj, KlassHandle klass_filter) {
1012 if (!klass_filter.is_null()) {
1013 if (obj->klass() != klass_filter()) {
1014 return true;
1015 }
1016 }
1017 return false;
1018 }
1019
1020 // helper function to tell if a field is a primitive field or not
1021 static inline bool is_primitive_field_type(char type) {
1022 return (type != 'L' && type != '[');
1023 }
1024
1025 // helper function to copy the value from location addr to jvalue.
1026 static inline void copy_to_jvalue(jvalue *v, address addr, jvmtiPrimitiveType value_type) {
1027 switch (value_type) {
1028 case JVMTI_PRIMITIVE_TYPE_BOOLEAN : { v->z = *(jboolean*)addr; break; }
1029 case JVMTI_PRIMITIVE_TYPE_BYTE : { v->b = *(jbyte*)addr; break; }
1030 case JVMTI_PRIMITIVE_TYPE_CHAR : { v->c = *(jchar*)addr; break; }
1031 case JVMTI_PRIMITIVE_TYPE_SHORT : { v->s = *(jshort*)addr; break; }
1032 case JVMTI_PRIMITIVE_TYPE_INT : { v->i = *(jint*)addr; break; }
1033 case JVMTI_PRIMITIVE_TYPE_LONG : { v->j = *(jlong*)addr; break; }
1034 case JVMTI_PRIMITIVE_TYPE_FLOAT : { v->f = *(jfloat*)addr; break; }
1035 case JVMTI_PRIMITIVE_TYPE_DOUBLE : { v->d = *(jdouble*)addr; break; }
1036 default: ShouldNotReachHere();
1037 }
1038 }
1039
1040 // helper function to invoke string primitive value callback
1041 // returns visit control flags
1042 static jint invoke_string_value_callback(jvmtiStringPrimitiveValueCallback cb,
1043 CallbackWrapper* wrapper,
1044 oop str,
1045 void* user_data)
1046 {
1047 assert(str->klass() == SystemDictionary::String_klass(), "not a string");
1048
1049 typeArrayOop s_value = java_lang_String::value(str);
1050
1051 // JDK-6584008: the value field may be null if a String instance is
1052 // partially constructed.
1053 if (s_value == NULL) {
1054 return 0;
1055 }
1056 // get the string value and length
1057 // (string value may be offset from the base)
1058 int s_len = java_lang_String::length(str);
1059 int s_offset = java_lang_String::offset(str);
1060 jchar* value;
1061 if (s_len > 0) {
1062 value = s_value->char_at_addr(s_offset);
1063 } else {
1064 value = (jchar*) s_value->base(T_CHAR);
1065 }
1066
1067 // invoke the callback
1068 return (*cb)(wrapper->klass_tag(),
1069 wrapper->obj_size(),
1070 wrapper->obj_tag_p(),
1071 value,
1072 (jint)s_len,
1073 user_data);
1074 }
1075
1076 // helper function to invoke string primitive value callback
1077 // returns visit control flags
1078 static jint invoke_array_primitive_value_callback(jvmtiArrayPrimitiveValueCallback cb,
1079 CallbackWrapper* wrapper,
1080 oop obj,
1081 void* user_data)
1082 {
1083 assert(obj->is_typeArray(), "not a primitive array");
1084
1085 // get base address of first element
1086 typeArrayOop array = typeArrayOop(obj);
1087 BasicType type = TypeArrayKlass::cast(array->klass())->element_type();
1088 void* elements = array->base(type);
1089
1090 // jvmtiPrimitiveType is defined so this mapping is always correct
1091 jvmtiPrimitiveType elem_type = (jvmtiPrimitiveType)type2char(type);
1092
1093 return (*cb)(wrapper->klass_tag(),
1094 wrapper->obj_size(),
1095 wrapper->obj_tag_p(),
1096 (jint)array->length(),
1097 elem_type,
1098 elements,
1099 user_data);
1100 }
1101
1102 // helper function to invoke the primitive field callback for all static fields
1103 // of a given class
1104 static jint invoke_primitive_field_callback_for_static_fields
1105 (CallbackWrapper* wrapper,
1106 oop obj,
1107 jvmtiPrimitiveFieldCallback cb,
1108 void* user_data)
1109 {
1110 // for static fields only the index will be set
1111 static jvmtiHeapReferenceInfo reference_info = { 0 };
1112
1113 assert(obj->klass() == SystemDictionary::Class_klass(), "not a class");
1114 if (java_lang_Class::is_primitive(obj)) {
1115 return 0;
1116 }
1117 Klass* klass = java_lang_Class::as_Klass(obj);
1118
1119 // ignore classes for object and type arrays
1120 if (!klass->oop_is_instance()) {
1121 return 0;
1122 }
1123
1124 // ignore classes which aren't linked yet
1125 InstanceKlass* ik = InstanceKlass::cast(klass);
1126 if (!ik->is_linked()) {
1127 return 0;
1128 }
1129
1130 // get the field map
1131 ClassFieldMap* field_map = ClassFieldMap::create_map_of_static_fields(klass);
1132
1133 // invoke the callback for each static primitive field
1134 for (int i=0; i<field_map->field_count(); i++) {
1135 ClassFieldDescriptor* field = field_map->field_at(i);
1136
1137 // ignore non-primitive fields
1138 char type = field->field_type();
1139 if (!is_primitive_field_type(type)) {
1140 continue;
1141 }
1142 // one-to-one mapping
1143 jvmtiPrimitiveType value_type = (jvmtiPrimitiveType)type;
1144
1145 // get offset and field value
1146 int offset = field->field_offset();
1147 address addr = (address)klass->java_mirror() + offset;
1148 jvalue value;
1149 copy_to_jvalue(&value, addr, value_type);
1150
1151 // field index
1152 reference_info.field.index = field->field_index();
1153
1154 // invoke the callback
1155 jint res = (*cb)(JVMTI_HEAP_REFERENCE_STATIC_FIELD,
1156 &reference_info,
1157 wrapper->klass_tag(),
1158 wrapper->obj_tag_p(),
1159 value,
1160 value_type,
1161 user_data);
1162 if (res & JVMTI_VISIT_ABORT) {
1163 delete field_map;
1164 return res;
1165 }
1166 }
1167
1168 delete field_map;
1169 return 0;
1170 }
1171
1172 // helper function to invoke the primitive field callback for all instance fields
1173 // of a given object
1174 static jint invoke_primitive_field_callback_for_instance_fields(
1175 CallbackWrapper* wrapper,
1176 oop obj,
1177 jvmtiPrimitiveFieldCallback cb,
1178 void* user_data)
1179 {
1180 // for instance fields only the index will be set
1181 static jvmtiHeapReferenceInfo reference_info = { 0 };
1182
1183 // get the map of the instance fields
1184 ClassFieldMap* fields = JvmtiCachedClassFieldMap::get_map_of_instance_fields(obj);
1185
1186 // invoke the callback for each instance primitive field
1187 for (int i=0; i<fields->field_count(); i++) {
1188 ClassFieldDescriptor* field = fields->field_at(i);
1189
1190 // ignore non-primitive fields
1191 char type = field->field_type();
1192 if (!is_primitive_field_type(type)) {
1193 continue;
1194 }
1195 // one-to-one mapping
1196 jvmtiPrimitiveType value_type = (jvmtiPrimitiveType)type;
1197
1198 // get offset and field value
1199 int offset = field->field_offset();
1200 address addr = (address)obj + offset;
1201 jvalue value;
1202 copy_to_jvalue(&value, addr, value_type);
1203
1204 // field index
1205 reference_info.field.index = field->field_index();
1206
1207 // invoke the callback
1208 jint res = (*cb)(JVMTI_HEAP_REFERENCE_FIELD,
1209 &reference_info,
1210 wrapper->klass_tag(),
1211 wrapper->obj_tag_p(),
1212 value,
1213 value_type,
1214 user_data);
1215 if (res & JVMTI_VISIT_ABORT) {
1216 return res;
1217 }
1218 }
1219 return 0;
1220 }
1221
1222
1223 // VM operation to iterate over all objects in the heap (both reachable
1224 // and unreachable)
1225 class VM_HeapIterateOperation: public VM_Operation {
1226 private:
1227 ObjectClosure* _blk;
1228 public:
1229 VM_HeapIterateOperation(ObjectClosure* blk) { _blk = blk; }
1230
1231 VMOp_Type type() const { return VMOp_HeapIterateOperation; }
1232 void doit() {
1233 // allows class files maps to be cached during iteration
1234 ClassFieldMapCacheMark cm;
1235
1236 // make sure that heap is parsable (fills TLABs with filler objects)
1237 Universe::heap()->ensure_parsability(false); // no need to retire TLABs
1238
1239 // Verify heap before iteration - if the heap gets corrupted then
1240 // JVMTI's IterateOverHeap will crash.
1241 if (VerifyBeforeIteration) {
1242 Universe::verify();
1243 }
1244
1245 // do the iteration
1246 // If this operation encounters a bad object when using CMS,
1247 // consider using safe_object_iterate() which avoids perm gen
1248 // objects that may contain bad references.
1249 Universe::heap()->object_iterate(_blk);
1250 }
1251
1252 };
1253
1254
1255 // An ObjectClosure used to support the deprecated IterateOverHeap and
1256 // IterateOverInstancesOfClass functions
1257 class IterateOverHeapObjectClosure: public ObjectClosure {
1258 private:
1259 JvmtiTagMap* _tag_map;
1260 KlassHandle _klass;
1261 jvmtiHeapObjectFilter _object_filter;
1262 jvmtiHeapObjectCallback _heap_object_callback;
1263 const void* _user_data;
1264
1265 // accessors
1266 JvmtiTagMap* tag_map() const { return _tag_map; }
1267 jvmtiHeapObjectFilter object_filter() const { return _object_filter; }
1268 jvmtiHeapObjectCallback object_callback() const { return _heap_object_callback; }
1269 KlassHandle klass() const { return _klass; }
1270 const void* user_data() const { return _user_data; }
1271
1272 // indicates if iteration has been aborted
1273 bool _iteration_aborted;
1274 bool is_iteration_aborted() const { return _iteration_aborted; }
1275 void set_iteration_aborted(bool aborted) { _iteration_aborted = aborted; }
1276
1277 public:
1278 IterateOverHeapObjectClosure(JvmtiTagMap* tag_map,
1279 KlassHandle klass,
1280 jvmtiHeapObjectFilter object_filter,
1281 jvmtiHeapObjectCallback heap_object_callback,
1282 const void* user_data) :
1283 _tag_map(tag_map),
1284 _klass(klass),
1285 _object_filter(object_filter),
1286 _heap_object_callback(heap_object_callback),
1287 _user_data(user_data),
1288 _iteration_aborted(false)
1289 {
1290 }
1291
1292 void do_object(oop o);
1293 };
1294
1295 // invoked for each object in the heap
1296 void IterateOverHeapObjectClosure::do_object(oop o) {
1297 // check if iteration has been halted
1298 if (is_iteration_aborted()) return;
1299
1300 // ignore any objects that aren't visible to profiler
1301 if (!ServiceUtil::visible_oop(o)) return;
1302
1303 // instanceof check when filtering by klass
1304 if (!klass().is_null() && !o->is_a(klass()())) {
1305 return;
1306 }
1307 // prepare for the calllback
1308 CallbackWrapper wrapper(tag_map(), o);
1309
1310 // if the object is tagged and we're only interested in untagged objects
1311 // then don't invoke the callback. Similiarly, if the object is untagged
1312 // and we're only interested in tagged objects we skip the callback.
1313 if (wrapper.obj_tag() != 0) {
1314 if (object_filter() == JVMTI_HEAP_OBJECT_UNTAGGED) return;
1315 } else {
1316 if (object_filter() == JVMTI_HEAP_OBJECT_TAGGED) return;
1317 }
1318
1319 // invoke the agent's callback
1320 jvmtiIterationControl control = (*object_callback())(wrapper.klass_tag(),
1321 wrapper.obj_size(),
1322 wrapper.obj_tag_p(),
1323 (void*)user_data());
1324 if (control == JVMTI_ITERATION_ABORT) {
1325 set_iteration_aborted(true);
1326 }
1327 }
1328
1329 // An ObjectClosure used to support the IterateThroughHeap function
1330 class IterateThroughHeapObjectClosure: public ObjectClosure {
1331 private:
1332 JvmtiTagMap* _tag_map;
1333 KlassHandle _klass;
1334 int _heap_filter;
1335 const jvmtiHeapCallbacks* _callbacks;
1336 const void* _user_data;
1337
1338 // accessor functions
1339 JvmtiTagMap* tag_map() const { return _tag_map; }
1340 int heap_filter() const { return _heap_filter; }
1341 const jvmtiHeapCallbacks* callbacks() const { return _callbacks; }
1342 KlassHandle klass() const { return _klass; }
1343 const void* user_data() const { return _user_data; }
1344
1345 // indicates if the iteration has been aborted
1346 bool _iteration_aborted;
1347 bool is_iteration_aborted() const { return _iteration_aborted; }
1348
1349 // used to check the visit control flags. If the abort flag is set
1350 // then we set the iteration aborted flag so that the iteration completes
1351 // without processing any further objects
1352 bool check_flags_for_abort(jint flags) {
1353 bool is_abort = (flags & JVMTI_VISIT_ABORT) != 0;
1354 if (is_abort) {
1355 _iteration_aborted = true;
1356 }
1357 return is_abort;
1358 }
1359
1360 public:
1361 IterateThroughHeapObjectClosure(JvmtiTagMap* tag_map,
1362 KlassHandle klass,
1363 int heap_filter,
1364 const jvmtiHeapCallbacks* heap_callbacks,
1365 const void* user_data) :
1366 _tag_map(tag_map),
1367 _klass(klass),
1368 _heap_filter(heap_filter),
1369 _callbacks(heap_callbacks),
1370 _user_data(user_data),
1371 _iteration_aborted(false)
1372 {
1373 }
1374
1375 void do_object(oop o);
1376 };
1377
1378 // invoked for each object in the heap
1379 void IterateThroughHeapObjectClosure::do_object(oop obj) {
1380 // check if iteration has been halted
1381 if (is_iteration_aborted()) return;
1382
1383 // ignore any objects that aren't visible to profiler
1384 if (!ServiceUtil::visible_oop(obj)) return;
1385
1386 // apply class filter
1387 if (is_filtered_by_klass_filter(obj, klass())) return;
1388
1389 // prepare for callback
1390 CallbackWrapper wrapper(tag_map(), obj);
1391
1392 // check if filtered by the heap filter
1393 if (is_filtered_by_heap_filter(wrapper.obj_tag(), wrapper.klass_tag(), heap_filter())) {
1394 return;
1395 }
1396
1397 // for arrays we need the length, otherwise -1
1398 bool is_array = obj->is_array();
1399 int len = is_array ? arrayOop(obj)->length() : -1;
1400
1401 // invoke the object callback (if callback is provided)
1402 if (callbacks()->heap_iteration_callback != NULL) {
1403 jvmtiHeapIterationCallback cb = callbacks()->heap_iteration_callback;
1404 jint res = (*cb)(wrapper.klass_tag(),
1405 wrapper.obj_size(),
1406 wrapper.obj_tag_p(),
1407 (jint)len,
1408 (void*)user_data());
1409 if (check_flags_for_abort(res)) return;
1410 }
1411
1412 // for objects and classes we report primitive fields if callback provided
1413 if (callbacks()->primitive_field_callback != NULL && obj->is_instance()) {
1414 jint res;
1415 jvmtiPrimitiveFieldCallback cb = callbacks()->primitive_field_callback;
1416 if (obj->klass() == SystemDictionary::Class_klass()) {
1417 res = invoke_primitive_field_callback_for_static_fields(&wrapper,
1418 obj,
1419 cb,
1420 (void*)user_data());
1421 } else {
1422 res = invoke_primitive_field_callback_for_instance_fields(&wrapper,
1423 obj,
1424 cb,
1425 (void*)user_data());
1426 }
1427 if (check_flags_for_abort(res)) return;
1428 }
1429
1430 // string callback
1431 if (!is_array &&
1432 callbacks()->string_primitive_value_callback != NULL &&
1433 obj->klass() == SystemDictionary::String_klass()) {
1434 jint res = invoke_string_value_callback(
1435 callbacks()->string_primitive_value_callback,
1436 &wrapper,
1437 obj,
1438 (void*)user_data() );
1439 if (check_flags_for_abort(res)) return;
1440 }
1441
1442 // array callback
1443 if (is_array &&
1444 callbacks()->array_primitive_value_callback != NULL &&
1445 obj->is_typeArray()) {
1446 jint res = invoke_array_primitive_value_callback(
1447 callbacks()->array_primitive_value_callback,
1448 &wrapper,
1449 obj,
1450 (void*)user_data() );
1451 if (check_flags_for_abort(res)) return;
1452 }
1453 };
1454
1455
1456 // Deprecated function to iterate over all objects in the heap
1457 void JvmtiTagMap::iterate_over_heap(jvmtiHeapObjectFilter object_filter,
1458 KlassHandle klass,
1459 jvmtiHeapObjectCallback heap_object_callback,
1460 const void* user_data)
1461 {
1462 MutexLocker ml(Heap_lock);
1463 IterateOverHeapObjectClosure blk(this,
1464 klass,
1465 object_filter,
1466 heap_object_callback,
1467 user_data);
1468 VM_HeapIterateOperation op(&blk);
1469 VMThread::execute(&op);
1470 }
1471
1472
1473 // Iterates over all objects in the heap
1474 void JvmtiTagMap::iterate_through_heap(jint heap_filter,
1475 KlassHandle klass,
1476 const jvmtiHeapCallbacks* callbacks,
1477 const void* user_data)
1478 {
1479 MutexLocker ml(Heap_lock);
1480 IterateThroughHeapObjectClosure blk(this,
1481 klass,
1482 heap_filter,
1483 callbacks,
1484 user_data);
1485 VM_HeapIterateOperation op(&blk);
1486 VMThread::execute(&op);
1487 }
1488
1489 // support class for get_objects_with_tags
1490
1491 class TagObjectCollector : public JvmtiTagHashmapEntryClosure {
1492 private:
1493 JvmtiEnv* _env;
1494 jlong* _tags;
1495 jint _tag_count;
1496
1497 GrowableArray<jobject>* _object_results; // collected objects (JNI weak refs)
1498 GrowableArray<uint64_t>* _tag_results; // collected tags
1499
1500 public:
1501 TagObjectCollector(JvmtiEnv* env, const jlong* tags, jint tag_count) {
1502 _env = env;
1503 _tags = (jlong*)tags;
1504 _tag_count = tag_count;
1505 _object_results = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<jobject>(1,true);
1506 _tag_results = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<uint64_t>(1,true);
1507 }
1508
1509 ~TagObjectCollector() {
1510 delete _object_results;
1511 delete _tag_results;
1512 }
1513
1514 // for each tagged object check if the tag value matches
1515 // - if it matches then we create a JNI local reference to the object
1516 // and record the reference and tag value.
1517 //
1518 void do_entry(JvmtiTagHashmapEntry* entry) {
1519 for (int i=0; i<_tag_count; i++) {
1520 if (_tags[i] == entry->tag()) {
1521 oop o = entry->object();
1522 assert(o != NULL && Universe::heap()->is_in_reserved(o), "sanity check");
1523 jobject ref = JNIHandles::make_local(JavaThread::current(), o);
1524 _object_results->append(ref);
1525 _tag_results->append((uint64_t)entry->tag());
1526 }
1527 }
1528 }
1529
1530 // return the results from the collection
1531 //
1532 jvmtiError result(jint* count_ptr, jobject** object_result_ptr, jlong** tag_result_ptr) {
1533 jvmtiError error;
1534 int count = _object_results->length();
1535 assert(count >= 0, "sanity check");
1536
1537 // if object_result_ptr is not NULL then allocate the result and copy
1538 // in the object references.
1539 if (object_result_ptr != NULL) {
1540 error = _env->Allocate(count * sizeof(jobject), (unsigned char**)object_result_ptr);
1541 if (error != JVMTI_ERROR_NONE) {
1542 return error;
1543 }
1544 for (int i=0; i<count; i++) {
1545 (*object_result_ptr)[i] = _object_results->at(i);
1546 }
1547 }
1548
1549 // if tag_result_ptr is not NULL then allocate the result and copy
1550 // in the tag values.
1551 if (tag_result_ptr != NULL) {
1552 error = _env->Allocate(count * sizeof(jlong), (unsigned char**)tag_result_ptr);
1553 if (error != JVMTI_ERROR_NONE) {
1554 if (object_result_ptr != NULL) {
1555 _env->Deallocate((unsigned char*)object_result_ptr);
1556 }
1557 return error;
1558 }
1559 for (int i=0; i<count; i++) {
1560 (*tag_result_ptr)[i] = (jlong)_tag_results->at(i);
1561 }
1562 }
1563
1564 *count_ptr = count;
1565 return JVMTI_ERROR_NONE;
1566 }
1567 };
1568
1569 // return the list of objects with the specified tags
1570 jvmtiError JvmtiTagMap::get_objects_with_tags(const jlong* tags,
1571 jint count, jint* count_ptr, jobject** object_result_ptr, jlong** tag_result_ptr) {
1572
1573 TagObjectCollector collector(env(), tags, count);
1574 {
1575 // iterate over all tagged objects
1576 MutexLocker ml(lock());
1577 entry_iterate(&collector);
1578 }
1579 return collector.result(count_ptr, object_result_ptr, tag_result_ptr);
1580 }
1581
1582
1583 // ObjectMarker is used to support the marking objects when walking the
1584 // heap.
1585 //
1586 // This implementation uses the existing mark bits in an object for
1587 // marking. Objects that are marked must later have their headers restored.
1588 // As most objects are unlocked and don't have their identity hash computed
1589 // we don't have to save their headers. Instead we save the headers that
1590 // are "interesting". Later when the headers are restored this implementation
1591 // restores all headers to their initial value and then restores the few
1592 // objects that had interesting headers.
1593 //
1594 // Future work: This implementation currently uses growable arrays to save
1595 // the oop and header of interesting objects. As an optimization we could
1596 // use the same technique as the GC and make use of the unused area
1597 // between top() and end().
1598 //
1599
1600 // An ObjectClosure used to restore the mark bits of an object
1601 class RestoreMarksClosure : public ObjectClosure {
1602 public:
1603 void do_object(oop o) {
1604 if (o != NULL) {
1605 markOop mark = o->mark();
1606 if (mark->is_marked()) {
1607 o->init_mark();
1608 }
1609 }
1610 }
1611 };
1612
1613 // ObjectMarker provides the mark and visited functions
1614 class ObjectMarker : AllStatic {
1615 private:
1616 // saved headers
1617 static GrowableArray<oop>* _saved_oop_stack;
1618 static GrowableArray<markOop>* _saved_mark_stack;
1619 static bool _needs_reset; // do we need to reset mark bits?
1620
1621 public:
1622 static void init(); // initialize
1623 static void done(); // clean-up
1624
1625 static inline void mark(oop o); // mark an object
1626 static inline bool visited(oop o); // check if object has been visited
1627
1628 static inline bool needs_reset() { return _needs_reset; }
1629 static inline void set_needs_reset(bool v) { _needs_reset = v; }
1630 };
1631
1632 GrowableArray<oop>* ObjectMarker::_saved_oop_stack = NULL;
1633 GrowableArray<markOop>* ObjectMarker::_saved_mark_stack = NULL;
1634 bool ObjectMarker::_needs_reset = true; // need to reset mark bits by default
1635
1636 // initialize ObjectMarker - prepares for object marking
1637 void ObjectMarker::init() {
1638 assert(Thread::current()->is_VM_thread(), "must be VMThread");
1639
1640 // prepare heap for iteration
1641 Universe::heap()->ensure_parsability(false); // no need to retire TLABs
1642
1643 // create stacks for interesting headers
1644 _saved_mark_stack = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<markOop>(4000, true);
1645 _saved_oop_stack = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<oop>(4000, true);
1646
1647 if (UseBiasedLocking) {
1648 BiasedLocking::preserve_marks();
1649 }
1650 }
1651
1652 // Object marking is done so restore object headers
1653 void ObjectMarker::done() {
1654 // iterate over all objects and restore the mark bits to
1655 // their initial value
1656 RestoreMarksClosure blk;
1657 if (needs_reset()) {
1658 Universe::heap()->object_iterate(&blk);
1659 } else {
1660 // We don't need to reset mark bits on this call, but reset the
1661 // flag to the default for the next call.
1662 set_needs_reset(true);
1663 }
1664
1665 // now restore the interesting headers
1666 for (int i = 0; i < _saved_oop_stack->length(); i++) {
1667 oop o = _saved_oop_stack->at(i);
1668 markOop mark = _saved_mark_stack->at(i);
1669 o->set_mark(mark);
1670 }
1671
1672 if (UseBiasedLocking) {
1673 BiasedLocking::restore_marks();
1674 }
1675
1676 // free the stacks
1677 delete _saved_oop_stack;
1678 delete _saved_mark_stack;
1679 }
1680
1681 // mark an object
1682 inline void ObjectMarker::mark(oop o) {
1683 assert(Universe::heap()->is_in(o), "sanity check");
1684 assert(!o->mark()->is_marked(), "should only mark an object once");
1685
1686 // object's mark word
1687 markOop mark = o->mark();
1688
1689 if (mark->must_be_preserved(o)) {
1690 _saved_mark_stack->push(mark);
1691 _saved_oop_stack->push(o);
1692 }
1693
1694 // mark the object
1695 o->set_mark(markOopDesc::prototype()->set_marked());
1696 }
1697
1698 // return true if object is marked
1699 inline bool ObjectMarker::visited(oop o) {
1700 return o->mark()->is_marked();
1701 }
1702
1703 // Stack allocated class to help ensure that ObjectMarker is used
1704 // correctly. Constructor initializes ObjectMarker, destructor calls
1705 // ObjectMarker's done() function to restore object headers.
1706 class ObjectMarkerController : public StackObj {
1707 public:
1708 ObjectMarkerController() {
1709 ObjectMarker::init();
1710 }
1711 ~ObjectMarkerController() {
1712 ObjectMarker::done();
1713 }
1714 };
1715
1716
1717 // helper to map a jvmtiHeapReferenceKind to an old style jvmtiHeapRootKind
1718 // (not performance critical as only used for roots)
1719 static jvmtiHeapRootKind toJvmtiHeapRootKind(jvmtiHeapReferenceKind kind) {
1720 switch (kind) {
1721 case JVMTI_HEAP_REFERENCE_JNI_GLOBAL: return JVMTI_HEAP_ROOT_JNI_GLOBAL;
1722 case JVMTI_HEAP_REFERENCE_SYSTEM_CLASS: return JVMTI_HEAP_ROOT_SYSTEM_CLASS;
1723 case JVMTI_HEAP_REFERENCE_MONITOR: return JVMTI_HEAP_ROOT_MONITOR;
1724 case JVMTI_HEAP_REFERENCE_STACK_LOCAL: return JVMTI_HEAP_ROOT_STACK_LOCAL;
1725 case JVMTI_HEAP_REFERENCE_JNI_LOCAL: return JVMTI_HEAP_ROOT_JNI_LOCAL;
1726 case JVMTI_HEAP_REFERENCE_THREAD: return JVMTI_HEAP_ROOT_THREAD;
1727 case JVMTI_HEAP_REFERENCE_OTHER: return JVMTI_HEAP_ROOT_OTHER;
1728 default: ShouldNotReachHere(); return JVMTI_HEAP_ROOT_OTHER;
1729 }
1730 }
1731
1732 // Base class for all heap walk contexts. The base class maintains a flag
1733 // to indicate if the context is valid or not.
1734 class HeapWalkContext VALUE_OBJ_CLASS_SPEC {
1735 private:
1736 bool _valid;
1737 public:
1738 HeapWalkContext(bool valid) { _valid = valid; }
1739 void invalidate() { _valid = false; }
1740 bool is_valid() const { return _valid; }
1741 };
1742
1743 // A basic heap walk context for the deprecated heap walking functions.
1744 // The context for a basic heap walk are the callbacks and fields used by
1745 // the referrer caching scheme.
1746 class BasicHeapWalkContext: public HeapWalkContext {
1747 private:
1748 jvmtiHeapRootCallback _heap_root_callback;
1749 jvmtiStackReferenceCallback _stack_ref_callback;
1750 jvmtiObjectReferenceCallback _object_ref_callback;
1751
1752 // used for caching
1753 oop _last_referrer;
1754 jlong _last_referrer_tag;
1755
1756 public:
1757 BasicHeapWalkContext() : HeapWalkContext(false) { }
1758
1759 BasicHeapWalkContext(jvmtiHeapRootCallback heap_root_callback,
1760 jvmtiStackReferenceCallback stack_ref_callback,
1761 jvmtiObjectReferenceCallback object_ref_callback) :
1762 HeapWalkContext(true),
1763 _heap_root_callback(heap_root_callback),
1764 _stack_ref_callback(stack_ref_callback),
1765 _object_ref_callback(object_ref_callback),
1766 _last_referrer(NULL),
1767 _last_referrer_tag(0) {
1768 }
1769
1770 // accessors
1771 jvmtiHeapRootCallback heap_root_callback() const { return _heap_root_callback; }
1772 jvmtiStackReferenceCallback stack_ref_callback() const { return _stack_ref_callback; }
1773 jvmtiObjectReferenceCallback object_ref_callback() const { return _object_ref_callback; }
1774
1775 oop last_referrer() const { return _last_referrer; }
1776 void set_last_referrer(oop referrer) { _last_referrer = referrer; }
1777 jlong last_referrer_tag() const { return _last_referrer_tag; }
1778 void set_last_referrer_tag(jlong value) { _last_referrer_tag = value; }
1779 };
1780
1781 // The advanced heap walk context for the FollowReferences functions.
1782 // The context is the callbacks, and the fields used for filtering.
1783 class AdvancedHeapWalkContext: public HeapWalkContext {
1784 private:
1785 jint _heap_filter;
1786 KlassHandle _klass_filter;
1787 const jvmtiHeapCallbacks* _heap_callbacks;
1788
1789 public:
1790 AdvancedHeapWalkContext() : HeapWalkContext(false) { }
1791
1792 AdvancedHeapWalkContext(jint heap_filter,
1793 KlassHandle klass_filter,
1794 const jvmtiHeapCallbacks* heap_callbacks) :
1795 HeapWalkContext(true),
1796 _heap_filter(heap_filter),
1797 _klass_filter(klass_filter),
1798 _heap_callbacks(heap_callbacks) {
1799 }
1800
1801 // accessors
1802 jint heap_filter() const { return _heap_filter; }
1803 KlassHandle klass_filter() const { return _klass_filter; }
1804
1805 const jvmtiHeapReferenceCallback heap_reference_callback() const {
1806 return _heap_callbacks->heap_reference_callback;
1807 };
1808 const jvmtiPrimitiveFieldCallback primitive_field_callback() const {
1809 return _heap_callbacks->primitive_field_callback;
1810 }
1811 const jvmtiArrayPrimitiveValueCallback array_primitive_value_callback() const {
1812 return _heap_callbacks->array_primitive_value_callback;
1813 }
1814 const jvmtiStringPrimitiveValueCallback string_primitive_value_callback() const {
1815 return _heap_callbacks->string_primitive_value_callback;
1816 }
1817 };
1818
1819 // The CallbackInvoker is a class with static functions that the heap walk can call
1820 // into to invoke callbacks. It works in one of two modes. The "basic" mode is
1821 // used for the deprecated IterateOverReachableObjects functions. The "advanced"
1822 // mode is for the newer FollowReferences function which supports a lot of
1823 // additional callbacks.
1824 class CallbackInvoker : AllStatic {
1825 private:
1826 // heap walk styles
1827 enum { basic, advanced };
1828 static int _heap_walk_type;
1829 static bool is_basic_heap_walk() { return _heap_walk_type == basic; }
1830 static bool is_advanced_heap_walk() { return _heap_walk_type == advanced; }
1831
1832 // context for basic style heap walk
1833 static BasicHeapWalkContext _basic_context;
1834 static BasicHeapWalkContext* basic_context() {
1835 assert(_basic_context.is_valid(), "invalid");
1836 return &_basic_context;
1837 }
1838
1839 // context for advanced style heap walk
1840 static AdvancedHeapWalkContext _advanced_context;
1841 static AdvancedHeapWalkContext* advanced_context() {
1842 assert(_advanced_context.is_valid(), "invalid");
1843 return &_advanced_context;
1844 }
1845
1846 // context needed for all heap walks
1847 static JvmtiTagMap* _tag_map;
1848 static const void* _user_data;
1849 static GrowableArray<oop>* _visit_stack;
1850
1851 // accessors
1852 static JvmtiTagMap* tag_map() { return _tag_map; }
1853 static const void* user_data() { return _user_data; }
1854 static GrowableArray<oop>* visit_stack() { return _visit_stack; }
1855
1856 // if the object hasn't been visited then push it onto the visit stack
1857 // so that it will be visited later
1858 static inline bool check_for_visit(oop obj) {
1859 if (!ObjectMarker::visited(obj)) visit_stack()->push(obj);
1860 return true;
1861 }
1862
1863 // invoke basic style callbacks
1864 static inline bool invoke_basic_heap_root_callback
1865 (jvmtiHeapRootKind root_kind, oop obj);
1866 static inline bool invoke_basic_stack_ref_callback
1867 (jvmtiHeapRootKind root_kind, jlong thread_tag, jint depth, jmethodID method,
1868 int slot, oop obj);
1869 static inline bool invoke_basic_object_reference_callback
1870 (jvmtiObjectReferenceKind ref_kind, oop referrer, oop referree, jint index);
1871
1872 // invoke advanced style callbacks
1873 static inline bool invoke_advanced_heap_root_callback
1874 (jvmtiHeapReferenceKind ref_kind, oop obj);
1875 static inline bool invoke_advanced_stack_ref_callback
1876 (jvmtiHeapReferenceKind ref_kind, jlong thread_tag, jlong tid, int depth,
1877 jmethodID method, jlocation bci, jint slot, oop obj);
1878 static inline bool invoke_advanced_object_reference_callback
1879 (jvmtiHeapReferenceKind ref_kind, oop referrer, oop referree, jint index);
1880
1881 // used to report the value of primitive fields
1882 static inline bool report_primitive_field
1883 (jvmtiHeapReferenceKind ref_kind, oop obj, jint index, address addr, char type);
1884
1885 public:
1886 // initialize for basic mode
1887 static void initialize_for_basic_heap_walk(JvmtiTagMap* tag_map,
1888 GrowableArray<oop>* visit_stack,
1889 const void* user_data,
1890 BasicHeapWalkContext context);
1891
1892 // initialize for advanced mode
1893 static void initialize_for_advanced_heap_walk(JvmtiTagMap* tag_map,
1894 GrowableArray<oop>* visit_stack,
1895 const void* user_data,
1896 AdvancedHeapWalkContext context);
1897
1898 // functions to report roots
1899 static inline bool report_simple_root(jvmtiHeapReferenceKind kind, oop o);
1900 static inline bool report_jni_local_root(jlong thread_tag, jlong tid, jint depth,
1901 jmethodID m, oop o);
1902 static inline bool report_stack_ref_root(jlong thread_tag, jlong tid, jint depth,
1903 jmethodID method, jlocation bci, jint slot, oop o);
1904
1905 // functions to report references
1906 static inline bool report_array_element_reference(oop referrer, oop referree, jint index);
1907 static inline bool report_class_reference(oop referrer, oop referree);
1908 static inline bool report_class_loader_reference(oop referrer, oop referree);
1909 static inline bool report_signers_reference(oop referrer, oop referree);
1910 static inline bool report_protection_domain_reference(oop referrer, oop referree);
1911 static inline bool report_superclass_reference(oop referrer, oop referree);
1912 static inline bool report_interface_reference(oop referrer, oop referree);
1913 static inline bool report_static_field_reference(oop referrer, oop referree, jint slot);
1914 static inline bool report_field_reference(oop referrer, oop referree, jint slot);
1915 static inline bool report_constant_pool_reference(oop referrer, oop referree, jint index);
1916 static inline bool report_primitive_array_values(oop array);
1917 static inline bool report_string_value(oop str);
1918 static inline bool report_primitive_instance_field(oop o, jint index, address value, char type);
1919 static inline bool report_primitive_static_field(oop o, jint index, address value, char type);
1920 };
1921
1922 // statics
1923 int CallbackInvoker::_heap_walk_type;
1924 BasicHeapWalkContext CallbackInvoker::_basic_context;
1925 AdvancedHeapWalkContext CallbackInvoker::_advanced_context;
1926 JvmtiTagMap* CallbackInvoker::_tag_map;
1927 const void* CallbackInvoker::_user_data;
1928 GrowableArray<oop>* CallbackInvoker::_visit_stack;
1929
1930 // initialize for basic heap walk (IterateOverReachableObjects et al)
1931 void CallbackInvoker::initialize_for_basic_heap_walk(JvmtiTagMap* tag_map,
1932 GrowableArray<oop>* visit_stack,
1933 const void* user_data,
1934 BasicHeapWalkContext context) {
1935 _tag_map = tag_map;
1936 _visit_stack = visit_stack;
1937 _user_data = user_data;
1938 _basic_context = context;
1939 _advanced_context.invalidate(); // will trigger assertion if used
1940 _heap_walk_type = basic;
1941 }
1942
1943 // initialize for advanced heap walk (FollowReferences)
1944 void CallbackInvoker::initialize_for_advanced_heap_walk(JvmtiTagMap* tag_map,
1945 GrowableArray<oop>* visit_stack,
1946 const void* user_data,
1947 AdvancedHeapWalkContext context) {
1948 _tag_map = tag_map;
1949 _visit_stack = visit_stack;
1950 _user_data = user_data;
1951 _advanced_context = context;
1952 _basic_context.invalidate(); // will trigger assertion if used
1953 _heap_walk_type = advanced;
1954 }
1955
1956
1957 // invoke basic style heap root callback
1958 inline bool CallbackInvoker::invoke_basic_heap_root_callback(jvmtiHeapRootKind root_kind, oop obj) {
1959 assert(ServiceUtil::visible_oop(obj), "checking");
1960
1961 // if we heap roots should be reported
1962 jvmtiHeapRootCallback cb = basic_context()->heap_root_callback();
1963 if (cb == NULL) {
1964 return check_for_visit(obj);
1965 }
1966
1967 CallbackWrapper wrapper(tag_map(), obj);
1968 jvmtiIterationControl control = (*cb)(root_kind,
1969 wrapper.klass_tag(),
1970 wrapper.obj_size(),
1971 wrapper.obj_tag_p(),
1972 (void*)user_data());
1973 // push root to visit stack when following references
1974 if (control == JVMTI_ITERATION_CONTINUE &&
1975 basic_context()->object_ref_callback() != NULL) {
1976 visit_stack()->push(obj);
1977 }
1978 return control != JVMTI_ITERATION_ABORT;
1979 }
1980
1981 // invoke basic style stack ref callback
1982 inline bool CallbackInvoker::invoke_basic_stack_ref_callback(jvmtiHeapRootKind root_kind,
1983 jlong thread_tag,
1984 jint depth,
1985 jmethodID method,
1986 jint slot,
1987 oop obj) {
1988 assert(ServiceUtil::visible_oop(obj), "checking");
1989
1990 // if we stack refs should be reported
1991 jvmtiStackReferenceCallback cb = basic_context()->stack_ref_callback();
1992 if (cb == NULL) {
1993 return check_for_visit(obj);
1994 }
1995
1996 CallbackWrapper wrapper(tag_map(), obj);
1997 jvmtiIterationControl control = (*cb)(root_kind,
1998 wrapper.klass_tag(),
1999 wrapper.obj_size(),
2000 wrapper.obj_tag_p(),
2001 thread_tag,
2002 depth,
2003 method,
2004 slot,
2005 (void*)user_data());
2006 // push root to visit stack when following references
2007 if (control == JVMTI_ITERATION_CONTINUE &&
2008 basic_context()->object_ref_callback() != NULL) {
2009 visit_stack()->push(obj);
2010 }
2011 return control != JVMTI_ITERATION_ABORT;
2012 }
2013
2014 // invoke basic style object reference callback
2015 inline bool CallbackInvoker::invoke_basic_object_reference_callback(jvmtiObjectReferenceKind ref_kind,
2016 oop referrer,
2017 oop referree,
2018 jint index) {
2019
2020 assert(ServiceUtil::visible_oop(referrer), "checking");
2021 assert(ServiceUtil::visible_oop(referree), "checking");
2022
2023 BasicHeapWalkContext* context = basic_context();
2024
2025 // callback requires the referrer's tag. If it's the same referrer
2026 // as the last call then we use the cached value.
2027 jlong referrer_tag;
2028 if (referrer == context->last_referrer()) {
2029 referrer_tag = context->last_referrer_tag();
2030 } else {
2031 referrer_tag = tag_for(tag_map(), referrer);
2032 }
2033
2034 // do the callback
2035 CallbackWrapper wrapper(tag_map(), referree);
2036 jvmtiObjectReferenceCallback cb = context->object_ref_callback();
2037 jvmtiIterationControl control = (*cb)(ref_kind,
2038 wrapper.klass_tag(),
2039 wrapper.obj_size(),
2040 wrapper.obj_tag_p(),
2041 referrer_tag,
2042 index,
2043 (void*)user_data());
2044
2045 // record referrer and referrer tag. For self-references record the
2046 // tag value from the callback as this might differ from referrer_tag.
2047 context->set_last_referrer(referrer);
2048 if (referrer == referree) {
2049 context->set_last_referrer_tag(*wrapper.obj_tag_p());
2050 } else {
2051 context->set_last_referrer_tag(referrer_tag);
2052 }
2053
2054 if (control == JVMTI_ITERATION_CONTINUE) {
2055 return check_for_visit(referree);
2056 } else {
2057 return control != JVMTI_ITERATION_ABORT;
2058 }
2059 }
2060
2061 // invoke advanced style heap root callback
2062 inline bool CallbackInvoker::invoke_advanced_heap_root_callback(jvmtiHeapReferenceKind ref_kind,
2063 oop obj) {
2064 assert(ServiceUtil::visible_oop(obj), "checking");
2065
2066 AdvancedHeapWalkContext* context = advanced_context();
2067
2068 // check that callback is provided
2069 jvmtiHeapReferenceCallback cb = context->heap_reference_callback();
2070 if (cb == NULL) {
2071 return check_for_visit(obj);
2072 }
2073
2074 // apply class filter
2075 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
2076 return check_for_visit(obj);
2077 }
2078
2079 // setup the callback wrapper
2080 CallbackWrapper wrapper(tag_map(), obj);
2081
2082 // apply tag filter
2083 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2084 wrapper.klass_tag(),
2085 context->heap_filter())) {
2086 return check_for_visit(obj);
2087 }
2088
2089 // for arrays we need the length, otherwise -1
2090 jint len = (jint)(obj->is_array() ? arrayOop(obj)->length() : -1);
2091
2092 // invoke the callback
2093 jint res = (*cb)(ref_kind,
2094 NULL, // referrer info
2095 wrapper.klass_tag(),
2096 0, // referrer_class_tag is 0 for heap root
2097 wrapper.obj_size(),
2098 wrapper.obj_tag_p(),
2099 NULL, // referrer_tag_p
2100 len,
2101 (void*)user_data());
2102 if (res & JVMTI_VISIT_ABORT) {
2103 return false;// referrer class tag
2104 }
2105 if (res & JVMTI_VISIT_OBJECTS) {
2106 check_for_visit(obj);
2107 }
2108 return true;
2109 }
2110
2111 // report a reference from a thread stack to an object
2112 inline bool CallbackInvoker::invoke_advanced_stack_ref_callback(jvmtiHeapReferenceKind ref_kind,
2113 jlong thread_tag,
2114 jlong tid,
2115 int depth,
2116 jmethodID method,
2117 jlocation bci,
2118 jint slot,
2119 oop obj) {
2120 assert(ServiceUtil::visible_oop(obj), "checking");
2121
2122 AdvancedHeapWalkContext* context = advanced_context();
2123
2124 // check that callback is provider
2125 jvmtiHeapReferenceCallback cb = context->heap_reference_callback();
2126 if (cb == NULL) {
2127 return check_for_visit(obj);
2128 }
2129
2130 // apply class filter
2131 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
2132 return check_for_visit(obj);
2133 }
2134
2135 // setup the callback wrapper
2136 CallbackWrapper wrapper(tag_map(), obj);
2137
2138 // apply tag filter
2139 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2140 wrapper.klass_tag(),
2141 context->heap_filter())) {
2142 return check_for_visit(obj);
2143 }
2144
2145 // setup the referrer info
2146 jvmtiHeapReferenceInfo reference_info;
2147 reference_info.stack_local.thread_tag = thread_tag;
2148 reference_info.stack_local.thread_id = tid;
2149 reference_info.stack_local.depth = depth;
2150 reference_info.stack_local.method = method;
2151 reference_info.stack_local.location = bci;
2152 reference_info.stack_local.slot = slot;
2153
2154 // for arrays we need the length, otherwise -1
2155 jint len = (jint)(obj->is_array() ? arrayOop(obj)->length() : -1);
2156
2157 // call into the agent
2158 int res = (*cb)(ref_kind,
2159 &reference_info,
2160 wrapper.klass_tag(),
2161 0, // referrer_class_tag is 0 for heap root (stack)
2162 wrapper.obj_size(),
2163 wrapper.obj_tag_p(),
2164 NULL, // referrer_tag is 0 for root
2165 len,
2166 (void*)user_data());
2167
2168 if (res & JVMTI_VISIT_ABORT) {
2169 return false;
2170 }
2171 if (res & JVMTI_VISIT_OBJECTS) {
2172 check_for_visit(obj);
2173 }
2174 return true;
2175 }
2176
2177 // This mask is used to pass reference_info to a jvmtiHeapReferenceCallback
2178 // only for ref_kinds defined by the JVM TI spec. Otherwise, NULL is passed.
2179 #define REF_INFO_MASK ((1 << JVMTI_HEAP_REFERENCE_FIELD) \
2180 | (1 << JVMTI_HEAP_REFERENCE_STATIC_FIELD) \
2181 | (1 << JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT) \
2182 | (1 << JVMTI_HEAP_REFERENCE_CONSTANT_POOL) \
2183 | (1 << JVMTI_HEAP_REFERENCE_STACK_LOCAL) \
2184 | (1 << JVMTI_HEAP_REFERENCE_JNI_LOCAL))
2185
2186 // invoke the object reference callback to report a reference
2187 inline bool CallbackInvoker::invoke_advanced_object_reference_callback(jvmtiHeapReferenceKind ref_kind,
2188 oop referrer,
2189 oop obj,
2190 jint index)
2191 {
2192 // field index is only valid field in reference_info
2193 static jvmtiHeapReferenceInfo reference_info = { 0 };
2194
2195 assert(ServiceUtil::visible_oop(referrer), "checking");
2196 assert(ServiceUtil::visible_oop(obj), "checking");
2197
2198 AdvancedHeapWalkContext* context = advanced_context();
2199
2200 // check that callback is provider
2201 jvmtiHeapReferenceCallback cb = context->heap_reference_callback();
2202 if (cb == NULL) {
2203 return check_for_visit(obj);
2204 }
2205
2206 // apply class filter
2207 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
2208 return check_for_visit(obj);
2209 }
2210
2211 // setup the callback wrapper
2212 TwoOopCallbackWrapper wrapper(tag_map(), referrer, obj);
2213
2214 // apply tag filter
2215 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2216 wrapper.klass_tag(),
2217 context->heap_filter())) {
2218 return check_for_visit(obj);
2219 }
2220
2221 // field index is only valid field in reference_info
2222 reference_info.field.index = index;
2223
2224 // for arrays we need the length, otherwise -1
2225 jint len = (jint)(obj->is_array() ? arrayOop(obj)->length() : -1);
2226
2227 // invoke the callback
2228 int res = (*cb)(ref_kind,
2229 (REF_INFO_MASK & (1 << ref_kind)) ? &reference_info : NULL,
2230 wrapper.klass_tag(),
2231 wrapper.referrer_klass_tag(),
2232 wrapper.obj_size(),
2233 wrapper.obj_tag_p(),
2234 wrapper.referrer_tag_p(),
2235 len,
2236 (void*)user_data());
2237
2238 if (res & JVMTI_VISIT_ABORT) {
2239 return false;
2240 }
2241 if (res & JVMTI_VISIT_OBJECTS) {
2242 check_for_visit(obj);
2243 }
2244 return true;
2245 }
2246
2247 // report a "simple root"
2248 inline bool CallbackInvoker::report_simple_root(jvmtiHeapReferenceKind kind, oop obj) {
2249 assert(kind != JVMTI_HEAP_REFERENCE_STACK_LOCAL &&
2250 kind != JVMTI_HEAP_REFERENCE_JNI_LOCAL, "not a simple root");
2251 assert(ServiceUtil::visible_oop(obj), "checking");
2252
2253 if (is_basic_heap_walk()) {
2254 // map to old style root kind
2255 jvmtiHeapRootKind root_kind = toJvmtiHeapRootKind(kind);
2256 return invoke_basic_heap_root_callback(root_kind, obj);
2257 } else {
2258 assert(is_advanced_heap_walk(), "wrong heap walk type");
2259 return invoke_advanced_heap_root_callback(kind, obj);
2260 }
2261 }
2262
2263
2264 // invoke the primitive array values
2265 inline bool CallbackInvoker::report_primitive_array_values(oop obj) {
2266 assert(obj->is_typeArray(), "not a primitive array");
2267
2268 AdvancedHeapWalkContext* context = advanced_context();
2269 assert(context->array_primitive_value_callback() != NULL, "no callback");
2270
2271 // apply class filter
2272 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
2273 return true;
2274 }
2275
2276 CallbackWrapper wrapper(tag_map(), obj);
2277
2278 // apply tag filter
2279 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2280 wrapper.klass_tag(),
2281 context->heap_filter())) {
2282 return true;
2283 }
2284
2285 // invoke the callback
2286 int res = invoke_array_primitive_value_callback(context->array_primitive_value_callback(),
2287 &wrapper,
2288 obj,
2289 (void*)user_data());
2290 return (!(res & JVMTI_VISIT_ABORT));
2291 }
2292
2293 // invoke the string value callback
2294 inline bool CallbackInvoker::report_string_value(oop str) {
2295 assert(str->klass() == SystemDictionary::String_klass(), "not a string");
2296
2297 AdvancedHeapWalkContext* context = advanced_context();
2298 assert(context->string_primitive_value_callback() != NULL, "no callback");
2299
2300 // apply class filter
2301 if (is_filtered_by_klass_filter(str, context->klass_filter())) {
2302 return true;
2303 }
2304
2305 CallbackWrapper wrapper(tag_map(), str);
2306
2307 // apply tag filter
2308 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2309 wrapper.klass_tag(),
2310 context->heap_filter())) {
2311 return true;
2312 }
2313
2314 // invoke the callback
2315 int res = invoke_string_value_callback(context->string_primitive_value_callback(),
2316 &wrapper,
2317 str,
2318 (void*)user_data());
2319 return (!(res & JVMTI_VISIT_ABORT));
2320 }
2321
2322 // invoke the primitive field callback
2323 inline bool CallbackInvoker::report_primitive_field(jvmtiHeapReferenceKind ref_kind,
2324 oop obj,
2325 jint index,
2326 address addr,
2327 char type)
2328 {
2329 // for primitive fields only the index will be set
2330 static jvmtiHeapReferenceInfo reference_info = { 0 };
2331
2332 AdvancedHeapWalkContext* context = advanced_context();
2333 assert(context->primitive_field_callback() != NULL, "no callback");
2334
2335 // apply class filter
2336 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
2337 return true;
2338 }
2339
2340 CallbackWrapper wrapper(tag_map(), obj);
2341
2342 // apply tag filter
2343 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2344 wrapper.klass_tag(),
2345 context->heap_filter())) {
2346 return true;
2347 }
2348
2349 // the field index in the referrer
2350 reference_info.field.index = index;
2351
2352 // map the type
2353 jvmtiPrimitiveType value_type = (jvmtiPrimitiveType)type;
2354
2355 // setup the jvalue
2356 jvalue value;
2357 copy_to_jvalue(&value, addr, value_type);
2358
2359 jvmtiPrimitiveFieldCallback cb = context->primitive_field_callback();
2360 int res = (*cb)(ref_kind,
2361 &reference_info,
2362 wrapper.klass_tag(),
2363 wrapper.obj_tag_p(),
2364 value,
2365 value_type,
2366 (void*)user_data());
2367 return (!(res & JVMTI_VISIT_ABORT));
2368 }
2369
2370
2371 // instance field
2372 inline bool CallbackInvoker::report_primitive_instance_field(oop obj,
2373 jint index,
2374 address value,
2375 char type) {
2376 return report_primitive_field(JVMTI_HEAP_REFERENCE_FIELD,
2377 obj,
2378 index,
2379 value,
2380 type);
2381 }
2382
2383 // static field
2384 inline bool CallbackInvoker::report_primitive_static_field(oop obj,
2385 jint index,
2386 address value,
2387 char type) {
2388 return report_primitive_field(JVMTI_HEAP_REFERENCE_STATIC_FIELD,
2389 obj,
2390 index,
2391 value,
2392 type);
2393 }
2394
2395 // report a JNI local (root object) to the profiler
2396 inline bool CallbackInvoker::report_jni_local_root(jlong thread_tag, jlong tid, jint depth, jmethodID m, oop obj) {
2397 if (is_basic_heap_walk()) {
2398 return invoke_basic_stack_ref_callback(JVMTI_HEAP_ROOT_JNI_LOCAL,
2399 thread_tag,
2400 depth,
2401 m,
2402 -1,
2403 obj);
2404 } else {
2405 return invoke_advanced_stack_ref_callback(JVMTI_HEAP_REFERENCE_JNI_LOCAL,
2406 thread_tag, tid,
2407 depth,
2408 m,
2409 (jlocation)-1,
2410 -1,
2411 obj);
2412 }
2413 }
2414
2415
2416 // report a local (stack reference, root object)
2417 inline bool CallbackInvoker::report_stack_ref_root(jlong thread_tag,
2418 jlong tid,
2419 jint depth,
2420 jmethodID method,
2421 jlocation bci,
2422 jint slot,
2423 oop obj) {
2424 if (is_basic_heap_walk()) {
2425 return invoke_basic_stack_ref_callback(JVMTI_HEAP_ROOT_STACK_LOCAL,
2426 thread_tag,
2427 depth,
2428 method,
2429 slot,
2430 obj);
2431 } else {
2432 return invoke_advanced_stack_ref_callback(JVMTI_HEAP_REFERENCE_STACK_LOCAL,
2433 thread_tag,
2434 tid,
2435 depth,
2436 method,
2437 bci,
2438 slot,
2439 obj);
2440 }
2441 }
2442
2443 // report an object referencing a class.
2444 inline bool CallbackInvoker::report_class_reference(oop referrer, oop referree) {
2445 if (is_basic_heap_walk()) {
2446 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CLASS, referrer, referree, -1);
2447 } else {
2448 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_CLASS, referrer, referree, -1);
2449 }
2450 }
2451
2452 // report a class referencing its class loader.
2453 inline bool CallbackInvoker::report_class_loader_reference(oop referrer, oop referree) {
2454 if (is_basic_heap_walk()) {
2455 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CLASS_LOADER, referrer, referree, -1);
2456 } else {
2457 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_CLASS_LOADER, referrer, referree, -1);
2458 }
2459 }
2460
2461 // report a class referencing its signers.
2462 inline bool CallbackInvoker::report_signers_reference(oop referrer, oop referree) {
2463 if (is_basic_heap_walk()) {
2464 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_SIGNERS, referrer, referree, -1);
2465 } else {
2466 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_SIGNERS, referrer, referree, -1);
2467 }
2468 }
2469
2470 // report a class referencing its protection domain..
2471 inline bool CallbackInvoker::report_protection_domain_reference(oop referrer, oop referree) {
2472 if (is_basic_heap_walk()) {
2473 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_PROTECTION_DOMAIN, referrer, referree, -1);
2474 } else {
2475 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_PROTECTION_DOMAIN, referrer, referree, -1);
2476 }
2477 }
2478
2479 // report a class referencing its superclass.
2480 inline bool CallbackInvoker::report_superclass_reference(oop referrer, oop referree) {
2481 if (is_basic_heap_walk()) {
2482 // Send this to be consistent with past implementation
2483 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CLASS, referrer, referree, -1);
2484 } else {
2485 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_SUPERCLASS, referrer, referree, -1);
2486 }
2487 }
2488
2489 // report a class referencing one of its interfaces.
2490 inline bool CallbackInvoker::report_interface_reference(oop referrer, oop referree) {
2491 if (is_basic_heap_walk()) {
2492 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_INTERFACE, referrer, referree, -1);
2493 } else {
2494 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_INTERFACE, referrer, referree, -1);
2495 }
2496 }
2497
2498 // report a class referencing one of its static fields.
2499 inline bool CallbackInvoker::report_static_field_reference(oop referrer, oop referree, jint slot) {
2500 if (is_basic_heap_walk()) {
2501 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_STATIC_FIELD, referrer, referree, slot);
2502 } else {
2503 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_STATIC_FIELD, referrer, referree, slot);
2504 }
2505 }
2506
2507 // report an array referencing an element object
2508 inline bool CallbackInvoker::report_array_element_reference(oop referrer, oop referree, jint index) {
2509 if (is_basic_heap_walk()) {
2510 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_ARRAY_ELEMENT, referrer, referree, index);
2511 } else {
2512 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT, referrer, referree, index);
2513 }
2514 }
2515
2516 // report an object referencing an instance field object
2517 inline bool CallbackInvoker::report_field_reference(oop referrer, oop referree, jint slot) {
2518 if (is_basic_heap_walk()) {
2519 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_FIELD, referrer, referree, slot);
2520 } else {
2521 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_FIELD, referrer, referree, slot);
2522 }
2523 }
2524
2525 // report an array referencing an element object
2526 inline bool CallbackInvoker::report_constant_pool_reference(oop referrer, oop referree, jint index) {
2527 if (is_basic_heap_walk()) {
2528 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CONSTANT_POOL, referrer, referree, index);
2529 } else {
2530 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_CONSTANT_POOL, referrer, referree, index);
2531 }
2532 }
2533
2534 // A supporting closure used to process simple roots
2535 class SimpleRootsClosure : public OopClosure {
2536 private:
2537 jvmtiHeapReferenceKind _kind;
2538 bool _continue;
2539
2540 jvmtiHeapReferenceKind root_kind() { return _kind; }
2541
2542 public:
2543 void set_kind(jvmtiHeapReferenceKind kind) {
2544 _kind = kind;
2545 _continue = true;
2546 }
2547
2548 inline bool stopped() {
2549 return !_continue;
2550 }
2551
2552 void do_oop(oop* obj_p) {
2553 // iteration has terminated
2554 if (stopped()) {
2555 return;
2556 }
2557
2558 // ignore null or deleted handles
2559 oop o = *obj_p;
2560 if (o == NULL || o == JNIHandles::deleted_handle()) {
2561 return;
2562 }
2563
2564 assert(Universe::heap()->is_in_reserved(o), "should be impossible");
2565
2566 jvmtiHeapReferenceKind kind = root_kind();
2567 if (kind == JVMTI_HEAP_REFERENCE_SYSTEM_CLASS) {
2568 // SystemDictionary::always_strong_oops_do reports the application
2569 // class loader as a root. We want this root to be reported as
2570 // a root kind of "OTHER" rather than "SYSTEM_CLASS".
2571 if (!o->is_instanceMirror()) {
2572 kind = JVMTI_HEAP_REFERENCE_OTHER;
2573 }
2574 }
2575
2576 // some objects are ignored - in the case of simple
2577 // roots it's mostly Symbol*s that we are skipping
2578 // here.
2579 if (!ServiceUtil::visible_oop(o)) {
2580 return;
2581 }
2582
2583 // invoke the callback
2584 _continue = CallbackInvoker::report_simple_root(kind, o);
2585
2586 }
2587 virtual void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }
2588 };
2589
2590 // A supporting closure used to process JNI locals
2591 class JNILocalRootsClosure : public OopClosure {
2592 private:
2593 jlong _thread_tag;
2594 jlong _tid;
2595 jint _depth;
2596 jmethodID _method;
2597 bool _continue;
2598 public:
2599 void set_context(jlong thread_tag, jlong tid, jint depth, jmethodID method) {
2600 _thread_tag = thread_tag;
2601 _tid = tid;
2602 _depth = depth;
2603 _method = method;
2604 _continue = true;
2605 }
2606
2607 inline bool stopped() {
2608 return !_continue;
2609 }
2610
2611 void do_oop(oop* obj_p) {
2612 // iteration has terminated
2613 if (stopped()) {
2614 return;
2615 }
2616
2617 // ignore null or deleted handles
2618 oop o = *obj_p;
2619 if (o == NULL || o == JNIHandles::deleted_handle()) {
2620 return;
2621 }
2622
2623 if (!ServiceUtil::visible_oop(o)) {
2624 return;
2625 }
2626
2627 // invoke the callback
2628 _continue = CallbackInvoker::report_jni_local_root(_thread_tag, _tid, _depth, _method, o);
2629 }
2630 virtual void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }
2631 };
2632
2633
2634 // A VM operation to iterate over objects that are reachable from
2635 // a set of roots or an initial object.
2636 //
2637 // For VM_HeapWalkOperation the set of roots used is :-
2638 //
2639 // - All JNI global references
2640 // - All inflated monitors
2641 // - All classes loaded by the boot class loader (or all classes
2642 // in the event that class unloading is disabled)
2643 // - All java threads
2644 // - For each java thread then all locals and JNI local references
2645 // on the thread's execution stack
2646 // - All visible/explainable objects from Universes::oops_do
2647 //
2648 class VM_HeapWalkOperation: public VM_Operation {
2649 private:
2650 enum {
2651 initial_visit_stack_size = 4000
2652 };
2653
2654 bool _is_advanced_heap_walk; // indicates FollowReferences
2655 JvmtiTagMap* _tag_map;
2656 Handle _initial_object;
2657 GrowableArray<oop>* _visit_stack; // the visit stack
2658
2659 bool _collecting_heap_roots; // are we collecting roots
2660 bool _following_object_refs; // are we following object references
2661
2662 bool _reporting_primitive_fields; // optional reporting
2663 bool _reporting_primitive_array_values;
2664 bool _reporting_string_values;
2665
2666 GrowableArray<oop>* create_visit_stack() {
2667 return new (ResourceObj::C_HEAP, mtInternal) GrowableArray<oop>(initial_visit_stack_size, true);
2668 }
2669
2670 // accessors
2671 bool is_advanced_heap_walk() const { return _is_advanced_heap_walk; }
2672 JvmtiTagMap* tag_map() const { return _tag_map; }
2673 Handle initial_object() const { return _initial_object; }
2674
2675 bool is_following_references() const { return _following_object_refs; }
2676
2677 bool is_reporting_primitive_fields() const { return _reporting_primitive_fields; }
2678 bool is_reporting_primitive_array_values() const { return _reporting_primitive_array_values; }
2679 bool is_reporting_string_values() const { return _reporting_string_values; }
2680
2681 GrowableArray<oop>* visit_stack() const { return _visit_stack; }
2682
2683 // iterate over the various object types
2684 inline bool iterate_over_array(oop o);
2685 inline bool iterate_over_type_array(oop o);
2686 inline bool iterate_over_class(oop o);
2687 inline bool iterate_over_object(oop o);
2688
2689 // root collection
2690 inline bool collect_simple_roots();
2691 inline bool collect_stack_roots();
2692 inline bool collect_stack_roots(JavaThread* java_thread, JNILocalRootsClosure* blk);
2693
2694 // visit an object
2695 inline bool visit(oop o);
2696
2697 public:
2698 VM_HeapWalkOperation(JvmtiTagMap* tag_map,
2699 Handle initial_object,
2700 BasicHeapWalkContext callbacks,
2701 const void* user_data);
2702
2703 VM_HeapWalkOperation(JvmtiTagMap* tag_map,
2704 Handle initial_object,
2705 AdvancedHeapWalkContext callbacks,
2706 const void* user_data);
2707
2708 ~VM_HeapWalkOperation();
2709
2710 VMOp_Type type() const { return VMOp_HeapWalkOperation; }
2711 void doit();
2712 };
2713
2714
2715 VM_HeapWalkOperation::VM_HeapWalkOperation(JvmtiTagMap* tag_map,
2716 Handle initial_object,
2717 BasicHeapWalkContext callbacks,
2718 const void* user_data) {
2719 _is_advanced_heap_walk = false;
2720 _tag_map = tag_map;
2721 _initial_object = initial_object;
2722 _following_object_refs = (callbacks.object_ref_callback() != NULL);
2723 _reporting_primitive_fields = false;
2724 _reporting_primitive_array_values = false;
2725 _reporting_string_values = false;
2726 _visit_stack = create_visit_stack();
2727
2728
2729 CallbackInvoker::initialize_for_basic_heap_walk(tag_map, _visit_stack, user_data, callbacks);
2730 }
2731
2732 VM_HeapWalkOperation::VM_HeapWalkOperation(JvmtiTagMap* tag_map,
2733 Handle initial_object,
2734 AdvancedHeapWalkContext callbacks,
2735 const void* user_data) {
2736 _is_advanced_heap_walk = true;
2737 _tag_map = tag_map;
2738 _initial_object = initial_object;
2739 _following_object_refs = true;
2740 _reporting_primitive_fields = (callbacks.primitive_field_callback() != NULL);;
2741 _reporting_primitive_array_values = (callbacks.array_primitive_value_callback() != NULL);;
2742 _reporting_string_values = (callbacks.string_primitive_value_callback() != NULL);;
2743 _visit_stack = create_visit_stack();
2744
2745 CallbackInvoker::initialize_for_advanced_heap_walk(tag_map, _visit_stack, user_data, callbacks);
2746 }
2747
2748 VM_HeapWalkOperation::~VM_HeapWalkOperation() {
2749 if (_following_object_refs) {
2750 assert(_visit_stack != NULL, "checking");
2751 delete _visit_stack;
2752 _visit_stack = NULL;
2753 }
2754 }
2755
2756 // an array references its class and has a reference to
2757 // each element in the array
2758 inline bool VM_HeapWalkOperation::iterate_over_array(oop o) {
2759 objArrayOop array = objArrayOop(o);
2760
2761 // array reference to its class
2762 oop mirror = ObjArrayKlass::cast(array->klass())->java_mirror();
2763 if (!CallbackInvoker::report_class_reference(o, mirror)) {
2764 return false;
2765 }
2766
2767 // iterate over the array and report each reference to a
2768 // non-null element
2769 for (int index=0; index<array->length(); index++) {
2770 oop elem = array->obj_at(index);
2771 if (elem == NULL) {
2772 continue;
2773 }
2774
2775 // report the array reference o[index] = elem
2776 if (!CallbackInvoker::report_array_element_reference(o, elem, index)) {
2777 return false;
2778 }
2779 }
2780 return true;
2781 }
2782
2783 // a type array references its class
2784 inline bool VM_HeapWalkOperation::iterate_over_type_array(oop o) {
2785 Klass* k = o->klass();
2786 oop mirror = k->java_mirror();
2787 if (!CallbackInvoker::report_class_reference(o, mirror)) {
2788 return false;
2789 }
2790
2791 // report the array contents if required
2792 if (is_reporting_primitive_array_values()) {
2793 if (!CallbackInvoker::report_primitive_array_values(o)) {
2794 return false;
2795 }
2796 }
2797 return true;
2798 }
2799
2800 #ifdef ASSERT
2801 // verify that a static oop field is in range
2802 static inline bool verify_static_oop(InstanceKlass* ik,
2803 oop mirror, int offset) {
2804 address obj_p = (address)mirror + offset;
2805 address start = (address)InstanceMirrorKlass::start_of_static_fields(mirror);
2806 address end = start + (java_lang_Class::static_oop_field_count(mirror) * heapOopSize);
2807 assert(end >= start, "sanity check");
2808
2809 if (obj_p >= start && obj_p < end) {
2810 return true;
2811 } else {
2812 return false;
2813 }
2814 }
2815 #endif // #ifdef ASSERT
2816
2817 // a class references its super class, interfaces, class loader, ...
2818 // and finally its static fields
2819 inline bool VM_HeapWalkOperation::iterate_over_class(oop java_class) {
2820 int i;
2821 Klass* klass = java_lang_Class::as_Klass(java_class);
2822
2823 if (klass->oop_is_instance()) {
2824 InstanceKlass* ik = InstanceKlass::cast(klass);
2825
2826 // ignore the class if it's has been initialized yet
2827 if (!ik->is_linked()) {
2828 return true;
2829 }
2830
2831 // get the java mirror
2832 oop mirror = klass->java_mirror();
2833
2834 // super (only if something more interesting than java.lang.Object)
2835 Klass* java_super = ik->java_super();
2836 if (java_super != NULL && java_super != SystemDictionary::Object_klass()) {
2837 oop super = java_super->java_mirror();
2838 if (!CallbackInvoker::report_superclass_reference(mirror, super)) {
2839 return false;
2840 }
2841 }
2842
2843 // class loader
2844 oop cl = ik->class_loader();
2845 if (cl != NULL) {
2846 if (!CallbackInvoker::report_class_loader_reference(mirror, cl)) {
2847 return false;
2848 }
2849 }
2850
2851 // protection domain
2852 oop pd = ik->protection_domain();
2853 if (pd != NULL) {
2854 if (!CallbackInvoker::report_protection_domain_reference(mirror, pd)) {
2855 return false;
2856 }
2857 }
2858
2859 // signers
2860 oop signers = ik->signers();
2861 if (signers != NULL) {
2862 if (!CallbackInvoker::report_signers_reference(mirror, signers)) {
2863 return false;
2864 }
2865 }
2866
2867 // references from the constant pool
2868 {
2869 ConstantPool* pool = ik->constants();
2870 for (int i = 1; i < pool->length(); i++) {
2871 constantTag tag = pool->tag_at(i).value();
2872 if (tag.is_string() || tag.is_klass()) {
2873 oop entry;
2874 if (tag.is_string()) {
2875 entry = pool->resolved_string_at(i);
2876 // If the entry is non-null it is resolved.
2877 if (entry == NULL) continue;
2878 } else {
2879 entry = pool->resolved_klass_at(i)->java_mirror();
2880 }
2881 if (!CallbackInvoker::report_constant_pool_reference(mirror, entry, (jint)i)) {
2882 return false;
2883 }
2884 }
2885 }
2886 }
2887
2888 // interfaces
2889 // (These will already have been reported as references from the constant pool
2890 // but are specified by IterateOverReachableObjects and must be reported).
2891 Array<Klass*>* interfaces = ik->local_interfaces();
2892 for (i = 0; i < interfaces->length(); i++) {
2893 oop interf = ((Klass*)interfaces->at(i))->java_mirror();
2894 if (interf == NULL) {
2895 continue;
2896 }
2897 if (!CallbackInvoker::report_interface_reference(mirror, interf)) {
2898 return false;
2899 }
2900 }
2901
2902 // iterate over the static fields
2903
2904 ClassFieldMap* field_map = ClassFieldMap::create_map_of_static_fields(klass);
2905 for (i=0; i<field_map->field_count(); i++) {
2906 ClassFieldDescriptor* field = field_map->field_at(i);
2907 char type = field->field_type();
2908 if (!is_primitive_field_type(type)) {
2909 oop fld_o = mirror->obj_field(field->field_offset());
2910 assert(verify_static_oop(ik, mirror, field->field_offset()), "sanity check");
2911 if (fld_o != NULL) {
2912 int slot = field->field_index();
2913 if (!CallbackInvoker::report_static_field_reference(mirror, fld_o, slot)) {
2914 delete field_map;
2915 return false;
2916 }
2917 }
2918 } else {
2919 if (is_reporting_primitive_fields()) {
2920 address addr = (address)mirror + field->field_offset();
2921 int slot = field->field_index();
2922 if (!CallbackInvoker::report_primitive_static_field(mirror, slot, addr, type)) {
2923 delete field_map;
2924 return false;
2925 }
2926 }
2927 }
2928 }
2929 delete field_map;
2930
2931 return true;
2932 }
2933
2934 return true;
2935 }
2936
2937 // an object references a class and its instance fields
2938 // (static fields are ignored here as we report these as
2939 // references from the class).
2940 inline bool VM_HeapWalkOperation::iterate_over_object(oop o) {
2941 // reference to the class
2942 if (!CallbackInvoker::report_class_reference(o, o->klass()->java_mirror())) {
2943 return false;
2944 }
2945
2946 // iterate over instance fields
2947 ClassFieldMap* field_map = JvmtiCachedClassFieldMap::get_map_of_instance_fields(o);
2948 for (int i=0; i<field_map->field_count(); i++) {
2949 ClassFieldDescriptor* field = field_map->field_at(i);
2950 char type = field->field_type();
2951 if (!is_primitive_field_type(type)) {
2952 oop fld_o = o->obj_field(field->field_offset());
2953 // ignore any objects that aren't visible to profiler
2954 if (fld_o != NULL && ServiceUtil::visible_oop(fld_o)) {
2955 assert(Universe::heap()->is_in_reserved(fld_o), "unsafe code should not "
2956 "have references to Klass* anymore");
2957 int slot = field->field_index();
2958 if (!CallbackInvoker::report_field_reference(o, fld_o, slot)) {
2959 return false;
2960 }
2961 }
2962 } else {
2963 if (is_reporting_primitive_fields()) {
2964 // primitive instance field
2965 address addr = (address)o + field->field_offset();
2966 int slot = field->field_index();
2967 if (!CallbackInvoker::report_primitive_instance_field(o, slot, addr, type)) {
2968 return false;
2969 }
2970 }
2971 }
2972 }
2973
2974 // if the object is a java.lang.String
2975 if (is_reporting_string_values() &&
2976 o->klass() == SystemDictionary::String_klass()) {
2977 if (!CallbackInvoker::report_string_value(o)) {
2978 return false;
2979 }
2980 }
2981 return true;
2982 }
2983
2984
2985 // Collects all simple (non-stack) roots except for threads;
2986 // threads are handled in collect_stack_roots() as an optimization.
2987 // if there's a heap root callback provided then the callback is
2988 // invoked for each simple root.
2989 // if an object reference callback is provided then all simple
2990 // roots are pushed onto the marking stack so that they can be
2991 // processed later
2992 //
2993 inline bool VM_HeapWalkOperation::collect_simple_roots() {
2994 SimpleRootsClosure blk;
2995
2996 // JNI globals
2997 blk.set_kind(JVMTI_HEAP_REFERENCE_JNI_GLOBAL);
2998 JNIHandles::oops_do(&blk);
2999 if (blk.stopped()) {
3000 return false;
3001 }
3002
3003 // Preloaded classes and loader from the system dictionary
3004 blk.set_kind(JVMTI_HEAP_REFERENCE_SYSTEM_CLASS);
3005 SystemDictionary::always_strong_oops_do(&blk);
3006 KlassToOopClosure klass_blk(&blk);
3007 ClassLoaderDataGraph::always_strong_oops_do(&blk, &klass_blk, false);
3008 if (blk.stopped()) {
3009 return false;
3010 }
3011
3012 // Inflated monitors
3013 blk.set_kind(JVMTI_HEAP_REFERENCE_MONITOR);
3014 ObjectSynchronizer::oops_do(&blk);
3015 if (blk.stopped()) {
3016 return false;
3017 }
3018
3019 // threads are now handled in collect_stack_roots()
3020
3021 // Other kinds of roots maintained by HotSpot
3022 // Many of these won't be visible but others (such as instances of important
3023 // exceptions) will be visible.
3024 blk.set_kind(JVMTI_HEAP_REFERENCE_OTHER);
3025 Universe::oops_do(&blk);
3026
3027 // If there are any non-perm roots in the code cache, visit them.
3028 blk.set_kind(JVMTI_HEAP_REFERENCE_OTHER);
3029 CodeBlobToOopClosure look_in_blobs(&blk, !CodeBlobToOopClosure::FixRelocations);
3030 CodeCache::scavenge_root_nmethods_do(&look_in_blobs);
3031
3032 return true;
3033 }
3034
3035 // Walk the stack of a given thread and find all references (locals
3036 // and JNI calls) and report these as stack references
3037 inline bool VM_HeapWalkOperation::collect_stack_roots(JavaThread* java_thread,
3038 JNILocalRootsClosure* blk)
3039 {
3040 oop threadObj = java_thread->threadObj();
3041 assert(threadObj != NULL, "sanity check");
3042
3043 // only need to get the thread's tag once per thread
3044 jlong thread_tag = tag_for(_tag_map, threadObj);
3045
3046 // also need the thread id
3047 jlong tid = java_lang_Thread::thread_id(threadObj);
3048
3049
3050 if (java_thread->has_last_Java_frame()) {
3051
3052 // vframes are resource allocated
3053 Thread* current_thread = Thread::current();
3054 ResourceMark rm(current_thread);
3055 HandleMark hm(current_thread);
3056
3057 RegisterMap reg_map(java_thread);
3058 frame f = java_thread->last_frame();
3059 vframe* vf = vframe::new_vframe(&f, ®_map, java_thread);
3060
3061 bool is_top_frame = true;
3062 int depth = 0;
3063 frame* last_entry_frame = NULL;
3064
3065 while (vf != NULL) {
3066 if (vf->is_java_frame()) {
3067
3068 // java frame (interpreted, compiled, ...)
3069 javaVFrame *jvf = javaVFrame::cast(vf);
3070
3071 // the jmethodID
3072 jmethodID method = jvf->method()->jmethod_id();
3073
3074 if (!(jvf->method()->is_native())) {
3075 jlocation bci = (jlocation)jvf->bci();
3076 StackValueCollection* locals = jvf->locals();
3077 for (int slot=0; slot<locals->size(); slot++) {
3078 if (locals->at(slot)->type() == T_OBJECT) {
3079 oop o = locals->obj_at(slot)();
3080 if (o == NULL) {
3081 continue;
3082 }
3083
3084 // stack reference
3085 if (!CallbackInvoker::report_stack_ref_root(thread_tag, tid, depth, method,
3086 bci, slot, o)) {
3087 return false;
3088 }
3089 }
3090 }
3091
3092 StackValueCollection* exprs = jvf->expressions();
3093 for (int index=0; index < exprs->size(); index++) {
3094 if (exprs->at(index)->type() == T_OBJECT) {
3095 oop o = exprs->obj_at(index)();
3096 if (o == NULL) {
3097 continue;
3098 }
3099
3100 // stack reference
3101 if (!CallbackInvoker::report_stack_ref_root(thread_tag, tid, depth, method,
3102 bci, locals->size() + index, o)) {
3103 return false;
3104 }
3105 }
3106 }
3107
3108 } else {
3109 blk->set_context(thread_tag, tid, depth, method);
3110 if (is_top_frame) {
3111 // JNI locals for the top frame.
3112 java_thread->active_handles()->oops_do(blk);
3113 } else {
3114 if (last_entry_frame != NULL) {
3115 // JNI locals for the entry frame
3116 assert(last_entry_frame->is_entry_frame(), "checking");
3117 last_entry_frame->entry_frame_call_wrapper()->handles()->oops_do(blk);
3118 }
3119 }
3120 }
3121 last_entry_frame = NULL;
3122 depth++;
3123 } else {
3124 // externalVFrame - for an entry frame then we report the JNI locals
3125 // when we find the corresponding javaVFrame
3126 frame* fr = vf->frame_pointer();
3127 assert(fr != NULL, "sanity check");
3128 if (fr->is_entry_frame()) {
3129 last_entry_frame = fr;
3130 }
3131 }
3132
3133 vf = vf->sender();
3134 is_top_frame = false;
3135 }
3136 } else {
3137 // no last java frame but there may be JNI locals
3138 blk->set_context(thread_tag, tid, 0, (jmethodID)NULL);
3139 java_thread->active_handles()->oops_do(blk);
3140 }
3141 return true;
3142 }
3143
3144
3145 // Collects the simple roots for all threads and collects all
3146 // stack roots - for each thread it walks the execution
3147 // stack to find all references and local JNI refs.
3148 inline bool VM_HeapWalkOperation::collect_stack_roots() {
3149 JNILocalRootsClosure blk;
3150 for (JavaThread* thread = Threads::first(); thread != NULL ; thread = thread->next()) {
3151 oop threadObj = thread->threadObj();
3152 if (threadObj != NULL && !thread->is_exiting() && !thread->is_hidden_from_external_view()) {
3153 // Collect the simple root for this thread before we
3154 // collect its stack roots
3155 if (!CallbackInvoker::report_simple_root(JVMTI_HEAP_REFERENCE_THREAD,
3156 threadObj)) {
3157 return false;
3158 }
3159 if (!collect_stack_roots(thread, &blk)) {
3160 return false;
3161 }
3162 }
3163 }
3164 return true;
3165 }
3166
3167 // visit an object
3168 // first mark the object as visited
3169 // second get all the outbound references from this object (in other words, all
3170 // the objects referenced by this object).
3171 //
3172 bool VM_HeapWalkOperation::visit(oop o) {
3173 // mark object as visited
3174 assert(!ObjectMarker::visited(o), "can't visit same object more than once");
3175 ObjectMarker::mark(o);
3176
3177 // instance
3178 if (o->is_instance()) {
3179 if (o->klass() == SystemDictionary::Class_klass()) {
3180 if (!java_lang_Class::is_primitive(o)) {
3181 // a java.lang.Class
3182 return iterate_over_class(o);
3183 }
3184 } else {
3185 return iterate_over_object(o);
3186 }
3187 }
3188
3189 // object array
3190 if (o->is_objArray()) {
3191 return iterate_over_array(o);
3192 }
3193
3194 // type array
3195 if (o->is_typeArray()) {
3196 return iterate_over_type_array(o);
3197 }
3198
3199 return true;
3200 }
3201
3202 void VM_HeapWalkOperation::doit() {
3203 ResourceMark rm;
3204 ObjectMarkerController marker;
3205 ClassFieldMapCacheMark cm;
3206
3207 assert(visit_stack()->is_empty(), "visit stack must be empty");
3208
3209 // the heap walk starts with an initial object or the heap roots
3210 if (initial_object().is_null()) {
3211 // If either collect_stack_roots() or collect_simple_roots()
3212 // returns false at this point, then there are no mark bits
3213 // to reset.
3214 ObjectMarker::set_needs_reset(false);
3215
3216 // Calling collect_stack_roots() before collect_simple_roots()
3217 // can result in a big performance boost for an agent that is
3218 // focused on analyzing references in the thread stacks.
3219 if (!collect_stack_roots()) return;
3220
3221 if (!collect_simple_roots()) return;
3222
3223 // no early return so enable heap traversal to reset the mark bits
3224 ObjectMarker::set_needs_reset(true);
3225 } else {
3226 visit_stack()->push(initial_object()());
3227 }
3228
3229 // object references required
3230 if (is_following_references()) {
3231
3232 // visit each object until all reachable objects have been
3233 // visited or the callback asked to terminate the iteration.
3234 while (!visit_stack()->is_empty()) {
3235 oop o = visit_stack()->pop();
3236 if (!ObjectMarker::visited(o)) {
3237 if (!visit(o)) {
3238 break;
3239 }
3240 }
3241 }
3242 }
3243 }
3244
3245 // iterate over all objects that are reachable from a set of roots
3246 void JvmtiTagMap::iterate_over_reachable_objects(jvmtiHeapRootCallback heap_root_callback,
3247 jvmtiStackReferenceCallback stack_ref_callback,
3248 jvmtiObjectReferenceCallback object_ref_callback,
3249 const void* user_data) {
3250 MutexLocker ml(Heap_lock);
3251 BasicHeapWalkContext context(heap_root_callback, stack_ref_callback, object_ref_callback);
3252 VM_HeapWalkOperation op(this, Handle(), context, user_data);
3253 VMThread::execute(&op);
3254 }
3255
3256 // iterate over all objects that are reachable from a given object
3257 void JvmtiTagMap::iterate_over_objects_reachable_from_object(jobject object,
3258 jvmtiObjectReferenceCallback object_ref_callback,
3259 const void* user_data) {
3260 oop obj = JNIHandles::resolve(object);
3261 Handle initial_object(Thread::current(), obj);
3262
3263 MutexLocker ml(Heap_lock);
3264 BasicHeapWalkContext context(NULL, NULL, object_ref_callback);
3265 VM_HeapWalkOperation op(this, initial_object, context, user_data);
3266 VMThread::execute(&op);
3267 }
3268
3269 // follow references from an initial object or the GC roots
3270 void JvmtiTagMap::follow_references(jint heap_filter,
3271 KlassHandle klass,
3272 jobject object,
3273 const jvmtiHeapCallbacks* callbacks,
3274 const void* user_data)
3275 {
3276 oop obj = JNIHandles::resolve(object);
3277 Handle initial_object(Thread::current(), obj);
3278
3279 MutexLocker ml(Heap_lock);
3280 AdvancedHeapWalkContext context(heap_filter, klass, callbacks);
3281 VM_HeapWalkOperation op(this, initial_object, context, user_data);
3282 VMThread::execute(&op);
3283 }
3284
3285
3286 void JvmtiTagMap::weak_oops_do(BoolObjectClosure* is_alive, OopClosure* f) {
3287 // No locks during VM bring-up (0 threads) and no safepoints after main
3288 // thread creation and before VMThread creation (1 thread); initial GC
3289 // verification can happen in that window which gets to here.
3290 assert(Threads::number_of_threads() <= 1 ||
3291 SafepointSynchronize::is_at_safepoint(),
3292 "must be executed at a safepoint");
3293 if (JvmtiEnv::environments_might_exist()) {
3294 JvmtiEnvIterator it;
3295 for (JvmtiEnvBase* env = it.first(); env != NULL; env = it.next(env)) {
3296 JvmtiTagMap* tag_map = env->tag_map();
3297 if (tag_map != NULL && !tag_map->is_empty()) {
3298 tag_map->do_weak_oops(is_alive, f);
3299 }
3300 }
3301 }
3302 }
3303
3304 void JvmtiTagMap::do_weak_oops(BoolObjectClosure* is_alive, OopClosure* f) {
3305
3306 // does this environment have the OBJECT_FREE event enabled
3307 bool post_object_free = env()->is_enabled(JVMTI_EVENT_OBJECT_FREE);
3308
3309 // counters used for trace message
3310 int freed = 0;
3311 int moved = 0;
3312
3313 JvmtiTagHashmap* hashmap = this->hashmap();
3314
3315 // reenable sizing (if disabled)
3316 hashmap->set_resizing_enabled(true);
3317
3318 // if the hashmap is empty then we can skip it
3319 if (hashmap->_entry_count == 0) {
3320 return;
3321 }
3322
3323 // now iterate through each entry in the table
3324
3325 JvmtiTagHashmapEntry** table = hashmap->table();
3326 int size = hashmap->size();
3327
3328 JvmtiTagHashmapEntry* delayed_add = NULL;
3329
3330 for (int pos = 0; pos < size; ++pos) {
3331 JvmtiTagHashmapEntry* entry = table[pos];
3332 JvmtiTagHashmapEntry* prev = NULL;
3333
3334 while (entry != NULL) {
3335 JvmtiTagHashmapEntry* next = entry->next();
3336
3337 oop* obj = entry->object_addr();
3338
3339 // has object been GC'ed
3340 if (!is_alive->do_object_b(entry->object())) {
3341 // grab the tag
3342 jlong tag = entry->tag();
3343 guarantee(tag != 0, "checking");
3344
3345 // remove GC'ed entry from hashmap and return the
3346 // entry to the free list
3347 hashmap->remove(prev, pos, entry);
3348 destroy_entry(entry);
3349
3350 // post the event to the profiler
3351 if (post_object_free) {
3352 JvmtiExport::post_object_free(env(), tag);
3353 }
3354
3355 ++freed;
3356 } else {
3357 f->do_oop(entry->object_addr());
3358 oop new_oop = entry->object();
3359
3360 // if the object has moved then re-hash it and move its
3361 // entry to its new location.
3362 unsigned int new_pos = JvmtiTagHashmap::hash(new_oop, size);
3363 if (new_pos != (unsigned int)pos) {
3364 if (prev == NULL) {
3365 table[pos] = next;
3366 } else {
3367 prev->set_next(next);
3368 }
3369 if (new_pos < (unsigned int)pos) {
3370 entry->set_next(table[new_pos]);
3371 table[new_pos] = entry;
3372 } else {
3373 // Delay adding this entry to it's new position as we'd end up
3374 // hitting it again during this iteration.
3375 entry->set_next(delayed_add);
3376 delayed_add = entry;
3377 }
3378 moved++;
3379 } else {
3380 // object didn't move
3381 prev = entry;
3382 }
3383 }
3384
3385 entry = next;
3386 }
3387 }
3388
3389 // Re-add all the entries which were kept aside
3390 while (delayed_add != NULL) {
3391 JvmtiTagHashmapEntry* next = delayed_add->next();
3392 unsigned int pos = JvmtiTagHashmap::hash(delayed_add->object(), size);
3393 delayed_add->set_next(table[pos]);
3394 table[pos] = delayed_add;
3395 delayed_add = next;
3396 }
3397
3398 // stats
3399 if (TraceJVMTIObjectTagging) {
3400 int post_total = hashmap->_entry_count;
3401 int pre_total = post_total + freed;
3402
3403 tty->print_cr("(%d->%d, %d freed, %d total moves)",
3404 pre_total, post_total, freed, moved);
3405 }
3406 }