1 /*
2 * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/javaClasses.inline.hpp"
27 #include "classfile/symbolTable.hpp"
28 #include "classfile/systemDictionary.hpp"
29 #include "classfile/vmSymbols.hpp"
30 #include "code/codeCache.hpp"
31 #include "jvmtifiles/jvmtiEnv.hpp"
32 #include "memory/allocation.inline.hpp"
33 #include "memory/resourceArea.hpp"
34 #include "oops/access.inline.hpp"
35 #include "oops/arrayOop.inline.hpp"
36 #include "oops/constantPool.inline.hpp"
37 #include "oops/instanceMirrorKlass.hpp"
38 #include "oops/objArrayKlass.hpp"
39 #include "oops/objArrayOop.inline.hpp"
40 #include "oops/oop.inline.hpp"
41 #include "oops/typeArrayOop.inline.hpp"
42 #include "prims/jvmtiEventController.hpp"
43 #include "prims/jvmtiEventController.inline.hpp"
44 #include "prims/jvmtiExport.hpp"
45 #include "prims/jvmtiImpl.hpp"
46 #include "prims/jvmtiTagMap.hpp"
47 #include "runtime/biasedLocking.hpp"
48 #include "runtime/frame.inline.hpp"
49 #include "runtime/handles.inline.hpp"
50 #include "runtime/javaCalls.hpp"
51 #include "runtime/jniHandles.inline.hpp"
52 #include "runtime/mutex.hpp"
53 #include "runtime/mutexLocker.hpp"
54 #include "runtime/reflectionUtils.hpp"
55 #include "runtime/thread.inline.hpp"
56 #include "runtime/threadSMR.hpp"
57 #include "runtime/vframe.hpp"
58 #include "runtime/vmThread.hpp"
59 #include "runtime/vm_operations.hpp"
60 #include "services/serviceUtil.hpp"
61 #include "utilities/macros.hpp"
62
63 // JvmtiTagHashmapEntry
64 //
65 // Each entry encapsulates a reference to the tagged object
66 // and the tag value. In addition an entry includes a next pointer which
67 // is used to chain entries together.
68
69 class JvmtiTagHashmapEntry : public CHeapObj<mtInternal> {
70 private:
71 friend class JvmtiTagMap;
72
73 oop _object; // tagged object
74 jlong _tag; // the tag
75 JvmtiTagHashmapEntry* _next; // next on the list
76
77 inline void init(oop object, jlong tag) {
78 _object = object;
79 _tag = tag;
80 _next = NULL;
81 }
82
83 // constructor
84 JvmtiTagHashmapEntry(oop object, jlong tag) { init(object, tag); }
85
86 public:
87
88 // accessor methods
89 inline oop* object_addr() { return &_object; }
90 inline oop object() { return RootAccess<ON_PHANTOM_OOP_REF>::oop_load(object_addr()); }
91 // Peek at the object without keeping it alive. The returned object must be
92 // kept alive using a normal access if it leaks out of a thread transition from VM.
93 inline oop object_peek() {
94 return RootAccess<ON_PHANTOM_OOP_REF | AS_NO_KEEPALIVE>::oop_load(object_addr());
95 }
96 inline jlong tag() const { return _tag; }
97
98 inline void set_tag(jlong tag) {
99 assert(tag != 0, "can't be zero");
100 _tag = tag;
101 }
102
103 inline bool equals(oop object) {
104 return object == object_peek();
105 }
106
107 inline JvmtiTagHashmapEntry* next() const { return _next; }
108 inline void set_next(JvmtiTagHashmapEntry* next) { _next = next; }
109 };
110
111
112 // JvmtiTagHashmap
113 //
114 // A hashmap is essentially a table of pointers to entries. Entries
115 // are hashed to a location, or position in the table, and then
116 // chained from that location. The "key" for hashing is address of
117 // the object, or oop. The "value" is the tag value.
118 //
119 // A hashmap maintains a count of the number entries in the hashmap
120 // and resizes if the number of entries exceeds a given threshold.
121 // The threshold is specified as a percentage of the size - for
122 // example a threshold of 0.75 will trigger the hashmap to resize
123 // if the number of entries is >75% of table size.
124 //
125 // A hashmap provides functions for adding, removing, and finding
126 // entries. It also provides a function to iterate over all entries
127 // in the hashmap.
128
129 class JvmtiTagHashmap : public CHeapObj<mtInternal> {
130 private:
131 friend class JvmtiTagMap;
132
133 enum {
134 small_trace_threshold = 10000, // threshold for tracing
135 medium_trace_threshold = 100000,
136 large_trace_threshold = 1000000,
137 initial_trace_threshold = small_trace_threshold
138 };
139
140 static int _sizes[]; // array of possible hashmap sizes
141 int _size; // actual size of the table
142 int _size_index; // index into size table
143
144 int _entry_count; // number of entries in the hashmap
145
146 float _load_factor; // load factor as a % of the size
147 int _resize_threshold; // computed threshold to trigger resizing.
148 bool _resizing_enabled; // indicates if hashmap can resize
149
150 int _trace_threshold; // threshold for trace messages
151
152 JvmtiTagHashmapEntry** _table; // the table of entries.
153
154 // private accessors
155 int resize_threshold() const { return _resize_threshold; }
156 int trace_threshold() const { return _trace_threshold; }
157
158 // initialize the hashmap
159 void init(int size_index=0, float load_factor=4.0f) {
160 int initial_size = _sizes[size_index];
161 _size_index = size_index;
162 _size = initial_size;
163 _entry_count = 0;
164 _trace_threshold = initial_trace_threshold;
165 _load_factor = load_factor;
166 _resize_threshold = (int)(_load_factor * _size);
167 _resizing_enabled = true;
168 size_t s = initial_size * sizeof(JvmtiTagHashmapEntry*);
169 _table = (JvmtiTagHashmapEntry**)os::malloc(s, mtInternal);
170 if (_table == NULL) {
171 vm_exit_out_of_memory(s, OOM_MALLOC_ERROR,
172 "unable to allocate initial hashtable for jvmti object tags");
173 }
174 for (int i=0; i<initial_size; i++) {
175 _table[i] = NULL;
176 }
177 }
178
179 // hash a given key (oop) with the specified size
180 static unsigned int hash(oop key, int size) {
181 // shift right to get better distribution (as these bits will be zero
182 // with aligned addresses)
183 unsigned int addr = (unsigned int)(cast_from_oop<intptr_t>(key));
184 #ifdef _LP64
185 return (addr >> 3) % size;
186 #else
187 return (addr >> 2) % size;
188 #endif
189 }
190
191 // hash a given key (oop)
192 unsigned int hash(oop key) {
193 return hash(key, _size);
194 }
195
196 // resize the hashmap - allocates a large table and re-hashes
197 // all entries into the new table.
198 void resize() {
199 int new_size_index = _size_index+1;
200 int new_size = _sizes[new_size_index];
201 if (new_size < 0) {
202 // hashmap already at maximum capacity
203 return;
204 }
205
206 // allocate new table
207 size_t s = new_size * sizeof(JvmtiTagHashmapEntry*);
208 JvmtiTagHashmapEntry** new_table = (JvmtiTagHashmapEntry**)os::malloc(s, mtInternal);
209 if (new_table == NULL) {
210 warning("unable to allocate larger hashtable for jvmti object tags");
211 set_resizing_enabled(false);
212 return;
213 }
214
215 // initialize new table
216 int i;
217 for (i=0; i<new_size; i++) {
218 new_table[i] = NULL;
219 }
220
221 // rehash all entries into the new table
222 for (i=0; i<_size; i++) {
223 JvmtiTagHashmapEntry* entry = _table[i];
224 while (entry != NULL) {
225 JvmtiTagHashmapEntry* next = entry->next();
226 oop key = entry->object_peek();
227 assert(key != NULL, "jni weak reference cleared!!");
228 unsigned int h = hash(key, new_size);
229 JvmtiTagHashmapEntry* anchor = new_table[h];
230 if (anchor == NULL) {
231 new_table[h] = entry;
232 entry->set_next(NULL);
233 } else {
234 entry->set_next(anchor);
235 new_table[h] = entry;
236 }
237 entry = next;
238 }
239 }
240
241 // free old table and update settings.
242 os::free((void*)_table);
243 _table = new_table;
244 _size_index = new_size_index;
245 _size = new_size;
246
247 // compute new resize threshold
248 _resize_threshold = (int)(_load_factor * _size);
249 }
250
251
252 // internal remove function - remove an entry at a given position in the
253 // table.
254 inline void remove(JvmtiTagHashmapEntry* prev, int pos, JvmtiTagHashmapEntry* entry) {
255 assert(pos >= 0 && pos < _size, "out of range");
256 if (prev == NULL) {
257 _table[pos] = entry->next();
258 } else {
259 prev->set_next(entry->next());
260 }
261 assert(_entry_count > 0, "checking");
262 _entry_count--;
263 }
264
265 // resizing switch
266 bool is_resizing_enabled() const { return _resizing_enabled; }
267 void set_resizing_enabled(bool enable) { _resizing_enabled = enable; }
268
269 // debugging
270 void print_memory_usage();
271 void compute_next_trace_threshold();
272
273 public:
274
275 // create a JvmtiTagHashmap of a preferred size and optionally a load factor.
276 // The preferred size is rounded down to an actual size.
277 JvmtiTagHashmap(int size, float load_factor=0.0f) {
278 int i=0;
279 while (_sizes[i] < size) {
280 if (_sizes[i] < 0) {
281 assert(i > 0, "sanity check");
282 i--;
283 break;
284 }
285 i++;
286 }
287
288 // if a load factor is specified then use it, otherwise use default
289 if (load_factor > 0.01f) {
290 init(i, load_factor);
291 } else {
292 init(i);
293 }
294 }
295
296 // create a JvmtiTagHashmap with default settings
297 JvmtiTagHashmap() {
298 init();
299 }
300
301 // release table when JvmtiTagHashmap destroyed
302 ~JvmtiTagHashmap() {
303 if (_table != NULL) {
304 os::free((void*)_table);
305 _table = NULL;
306 }
307 }
308
309 // accessors
310 int size() const { return _size; }
311 JvmtiTagHashmapEntry** table() const { return _table; }
312 int entry_count() const { return _entry_count; }
313
314 // find an entry in the hashmap, returns NULL if not found.
315 inline JvmtiTagHashmapEntry* find(oop key) {
316 unsigned int h = hash(key);
317 JvmtiTagHashmapEntry* entry = _table[h];
318 while (entry != NULL) {
319 if (entry->equals(key)) {
320 return entry;
321 }
322 entry = entry->next();
323 }
324 return NULL;
325 }
326
327
328 // add a new entry to hashmap
329 inline void add(oop key, JvmtiTagHashmapEntry* entry) {
330 assert(key != NULL, "checking");
331 assert(find(key) == NULL, "duplicate detected");
332 unsigned int h = hash(key);
333 JvmtiTagHashmapEntry* anchor = _table[h];
334 if (anchor == NULL) {
335 _table[h] = entry;
336 entry->set_next(NULL);
337 } else {
338 entry->set_next(anchor);
339 _table[h] = entry;
340 }
341
342 _entry_count++;
343 if (log_is_enabled(Debug, jvmti, objecttagging) && entry_count() >= trace_threshold()) {
344 print_memory_usage();
345 compute_next_trace_threshold();
346 }
347
348 // if the number of entries exceed the threshold then resize
349 if (entry_count() > resize_threshold() && is_resizing_enabled()) {
350 resize();
351 }
352 }
353
354 // remove an entry with the given key.
355 inline JvmtiTagHashmapEntry* remove(oop key) {
356 unsigned int h = hash(key);
357 JvmtiTagHashmapEntry* entry = _table[h];
358 JvmtiTagHashmapEntry* prev = NULL;
359 while (entry != NULL) {
360 if (entry->equals(key)) {
361 break;
362 }
363 prev = entry;
364 entry = entry->next();
365 }
366 if (entry != NULL) {
367 remove(prev, h, entry);
368 }
369 return entry;
370 }
371
372 // iterate over all entries in the hashmap
373 void entry_iterate(JvmtiTagHashmapEntryClosure* closure);
374 };
375
376 // possible hashmap sizes - odd primes that roughly double in size.
377 // To avoid excessive resizing the odd primes from 4801-76831 and
378 // 76831-307261 have been removed. The list must be terminated by -1.
379 int JvmtiTagHashmap::_sizes[] = { 4801, 76831, 307261, 614563, 1228891,
380 2457733, 4915219, 9830479, 19660831, 39321619, 78643219, -1 };
381
382
383 // A supporting class for iterating over all entries in Hashmap
384 class JvmtiTagHashmapEntryClosure {
385 public:
386 virtual void do_entry(JvmtiTagHashmapEntry* entry) = 0;
387 };
388
389
390 // iterate over all entries in the hashmap
391 void JvmtiTagHashmap::entry_iterate(JvmtiTagHashmapEntryClosure* closure) {
392 for (int i=0; i<_size; i++) {
393 JvmtiTagHashmapEntry* entry = _table[i];
394 JvmtiTagHashmapEntry* prev = NULL;
395 while (entry != NULL) {
396 // obtain the next entry before invoking do_entry - this is
397 // necessary because do_entry may remove the entry from the
398 // hashmap.
399 JvmtiTagHashmapEntry* next = entry->next();
400 closure->do_entry(entry);
401 entry = next;
402 }
403 }
404 }
405
406 // debugging
407 void JvmtiTagHashmap::print_memory_usage() {
408 intptr_t p = (intptr_t)this;
409 tty->print("[JvmtiTagHashmap @ " INTPTR_FORMAT, p);
410
411 // table + entries in KB
412 int hashmap_usage = (size()*sizeof(JvmtiTagHashmapEntry*) +
413 entry_count()*sizeof(JvmtiTagHashmapEntry))/K;
414
415 int weak_globals_usage = (int)(JNIHandles::weak_global_handle_memory_usage()/K);
416 tty->print_cr(", %d entries (%d KB) <JNI weak globals: %d KB>]",
417 entry_count(), hashmap_usage, weak_globals_usage);
418 }
419
420 // compute threshold for the next trace message
421 void JvmtiTagHashmap::compute_next_trace_threshold() {
422 _trace_threshold = entry_count();
423 if (trace_threshold() < medium_trace_threshold) {
424 _trace_threshold += small_trace_threshold;
425 } else {
426 if (trace_threshold() < large_trace_threshold) {
427 _trace_threshold += medium_trace_threshold;
428 } else {
429 _trace_threshold += large_trace_threshold;
430 }
431 }
432 }
433
434 // create a JvmtiTagMap
435 JvmtiTagMap::JvmtiTagMap(JvmtiEnv* env) :
436 _env(env),
437 _lock(Mutex::nonleaf+2, "JvmtiTagMap._lock", false),
438 _free_entries(NULL),
439 _free_entries_count(0)
440 {
441 assert(JvmtiThreadState_lock->is_locked(), "sanity check");
442 assert(((JvmtiEnvBase *)env)->tag_map() == NULL, "tag map already exists for environment");
443
444 _hashmap = new JvmtiTagHashmap();
445
446 // finally add us to the environment
447 ((JvmtiEnvBase *)env)->set_tag_map(this);
448 }
449
450
451 // destroy a JvmtiTagMap
452 JvmtiTagMap::~JvmtiTagMap() {
453
454 // no lock acquired as we assume the enclosing environment is
455 // also being destroryed.
456 ((JvmtiEnvBase *)_env)->set_tag_map(NULL);
457
458 JvmtiTagHashmapEntry** table = _hashmap->table();
459 for (int j = 0; j < _hashmap->size(); j++) {
460 JvmtiTagHashmapEntry* entry = table[j];
461 while (entry != NULL) {
462 JvmtiTagHashmapEntry* next = entry->next();
463 delete entry;
464 entry = next;
465 }
466 }
467
468 // finally destroy the hashmap
469 delete _hashmap;
470 _hashmap = NULL;
471
472 // remove any entries on the free list
473 JvmtiTagHashmapEntry* entry = _free_entries;
474 while (entry != NULL) {
475 JvmtiTagHashmapEntry* next = entry->next();
476 delete entry;
477 entry = next;
478 }
479 _free_entries = NULL;
480 }
481
482 // create a hashmap entry
483 // - if there's an entry on the (per-environment) free list then this
484 // is returned. Otherwise an new entry is allocated.
485 JvmtiTagHashmapEntry* JvmtiTagMap::create_entry(oop ref, jlong tag) {
486 assert(Thread::current()->is_VM_thread() || is_locked(), "checking");
487 JvmtiTagHashmapEntry* entry;
488 if (_free_entries == NULL) {
489 entry = new JvmtiTagHashmapEntry(ref, tag);
490 } else {
491 assert(_free_entries_count > 0, "mismatched _free_entries_count");
492 _free_entries_count--;
493 entry = _free_entries;
494 _free_entries = entry->next();
495 entry->init(ref, tag);
496 }
497 return entry;
498 }
499
500 // destroy an entry by returning it to the free list
501 void JvmtiTagMap::destroy_entry(JvmtiTagHashmapEntry* entry) {
502 assert(SafepointSynchronize::is_at_safepoint() || is_locked(), "checking");
503 // limit the size of the free list
504 if (_free_entries_count >= max_free_entries) {
505 delete entry;
506 } else {
507 entry->set_next(_free_entries);
508 _free_entries = entry;
509 _free_entries_count++;
510 }
511 }
512
513 // returns the tag map for the given environments. If the tag map
514 // doesn't exist then it is created.
515 JvmtiTagMap* JvmtiTagMap::tag_map_for(JvmtiEnv* env) {
516 JvmtiTagMap* tag_map = ((JvmtiEnvBase*)env)->tag_map();
517 if (tag_map == NULL) {
518 MutexLocker mu(JvmtiThreadState_lock);
519 tag_map = ((JvmtiEnvBase*)env)->tag_map();
520 if (tag_map == NULL) {
521 tag_map = new JvmtiTagMap(env);
522 }
523 } else {
524 CHECK_UNHANDLED_OOPS_ONLY(Thread::current()->clear_unhandled_oops());
525 }
526 return tag_map;
527 }
528
529 // iterate over all entries in the tag map.
530 void JvmtiTagMap::entry_iterate(JvmtiTagHashmapEntryClosure* closure) {
531 hashmap()->entry_iterate(closure);
532 }
533
534 // returns true if the hashmaps are empty
535 bool JvmtiTagMap::is_empty() {
536 assert(SafepointSynchronize::is_at_safepoint() || is_locked(), "checking");
537 return hashmap()->entry_count() == 0;
538 }
539
540
541 // Return the tag value for an object, or 0 if the object is
542 // not tagged
543 //
544 static inline jlong tag_for(JvmtiTagMap* tag_map, oop o) {
545 JvmtiTagHashmapEntry* entry = tag_map->hashmap()->find(o);
546 if (entry == NULL) {
547 return 0;
548 } else {
549 return entry->tag();
550 }
551 }
552
553
554 // A CallbackWrapper is a support class for querying and tagging an object
555 // around a callback to a profiler. The constructor does pre-callback
556 // work to get the tag value, klass tag value, ... and the destructor
557 // does the post-callback work of tagging or untagging the object.
558 //
559 // {
560 // CallbackWrapper wrapper(tag_map, o);
561 //
562 // (*callback)(wrapper.klass_tag(), wrapper.obj_size(), wrapper.obj_tag_p(), ...)
563 //
564 // } // wrapper goes out of scope here which results in the destructor
565 // checking to see if the object has been tagged, untagged, or the
566 // tag value has changed.
567 //
568 class CallbackWrapper : public StackObj {
569 private:
570 JvmtiTagMap* _tag_map;
571 JvmtiTagHashmap* _hashmap;
572 JvmtiTagHashmapEntry* _entry;
573 oop _o;
574 jlong _obj_size;
575 jlong _obj_tag;
576 jlong _klass_tag;
577
578 protected:
579 JvmtiTagMap* tag_map() const { return _tag_map; }
580
581 // invoked post-callback to tag, untag, or update the tag of an object
582 void inline post_callback_tag_update(oop o, JvmtiTagHashmap* hashmap,
583 JvmtiTagHashmapEntry* entry, jlong obj_tag);
584 public:
585 CallbackWrapper(JvmtiTagMap* tag_map, oop o) {
586 assert(Thread::current()->is_VM_thread() || tag_map->is_locked(),
587 "MT unsafe or must be VM thread");
588
589 // object to tag
590 _o = o;
591
592 // object size
593 _obj_size = (jlong)_o->size() * wordSize;
594
595 // record the context
596 _tag_map = tag_map;
597 _hashmap = tag_map->hashmap();
598 _entry = _hashmap->find(_o);
599
600 // get object tag
601 _obj_tag = (_entry == NULL) ? 0 : _entry->tag();
602
603 // get the class and the class's tag value
604 assert(SystemDictionary::Class_klass()->is_mirror_instance_klass(), "Is not?");
605
606 _klass_tag = tag_for(tag_map, _o->klass()->java_mirror());
607 }
608
609 ~CallbackWrapper() {
610 post_callback_tag_update(_o, _hashmap, _entry, _obj_tag);
611 }
612
613 inline jlong* obj_tag_p() { return &_obj_tag; }
614 inline jlong obj_size() const { return _obj_size; }
615 inline jlong obj_tag() const { return _obj_tag; }
616 inline jlong klass_tag() const { return _klass_tag; }
617 };
618
619
620
621 // callback post-callback to tag, untag, or update the tag of an object
622 void inline CallbackWrapper::post_callback_tag_update(oop o,
623 JvmtiTagHashmap* hashmap,
624 JvmtiTagHashmapEntry* entry,
625 jlong obj_tag) {
626 if (entry == NULL) {
627 if (obj_tag != 0) {
628 // callback has tagged the object
629 assert(Thread::current()->is_VM_thread(), "must be VMThread");
630 entry = tag_map()->create_entry(o, obj_tag);
631 hashmap->add(o, entry);
632 }
633 } else {
634 // object was previously tagged - the callback may have untagged
635 // the object or changed the tag value
636 if (obj_tag == 0) {
637
638 JvmtiTagHashmapEntry* entry_removed = hashmap->remove(o);
639 assert(entry_removed == entry, "checking");
640 tag_map()->destroy_entry(entry);
641
642 } else {
643 if (obj_tag != entry->tag()) {
644 entry->set_tag(obj_tag);
645 }
646 }
647 }
648 }
649
650 // An extended CallbackWrapper used when reporting an object reference
651 // to the agent.
652 //
653 // {
654 // TwoOopCallbackWrapper wrapper(tag_map, referrer, o);
655 //
656 // (*callback)(wrapper.klass_tag(),
657 // wrapper.obj_size(),
658 // wrapper.obj_tag_p()
659 // wrapper.referrer_tag_p(), ...)
660 //
661 // } // wrapper goes out of scope here which results in the destructor
662 // checking to see if the referrer object has been tagged, untagged,
663 // or the tag value has changed.
664 //
665 class TwoOopCallbackWrapper : public CallbackWrapper {
666 private:
667 bool _is_reference_to_self;
668 JvmtiTagHashmap* _referrer_hashmap;
669 JvmtiTagHashmapEntry* _referrer_entry;
670 oop _referrer;
671 jlong _referrer_obj_tag;
672 jlong _referrer_klass_tag;
673 jlong* _referrer_tag_p;
674
675 bool is_reference_to_self() const { return _is_reference_to_self; }
676
677 public:
678 TwoOopCallbackWrapper(JvmtiTagMap* tag_map, oop referrer, oop o) :
679 CallbackWrapper(tag_map, o)
680 {
681 // self reference needs to be handled in a special way
682 _is_reference_to_self = (referrer == o);
683
684 if (_is_reference_to_self) {
685 _referrer_klass_tag = klass_tag();
686 _referrer_tag_p = obj_tag_p();
687 } else {
688 _referrer = referrer;
689 // record the context
690 _referrer_hashmap = tag_map->hashmap();
691 _referrer_entry = _referrer_hashmap->find(_referrer);
692
693 // get object tag
694 _referrer_obj_tag = (_referrer_entry == NULL) ? 0 : _referrer_entry->tag();
695 _referrer_tag_p = &_referrer_obj_tag;
696
697 // get referrer class tag.
698 _referrer_klass_tag = tag_for(tag_map, _referrer->klass()->java_mirror());
699 }
700 }
701
702 ~TwoOopCallbackWrapper() {
703 if (!is_reference_to_self()){
704 post_callback_tag_update(_referrer,
705 _referrer_hashmap,
706 _referrer_entry,
707 _referrer_obj_tag);
708 }
709 }
710
711 // address of referrer tag
712 // (for a self reference this will return the same thing as obj_tag_p())
713 inline jlong* referrer_tag_p() { return _referrer_tag_p; }
714
715 // referrer's class tag
716 inline jlong referrer_klass_tag() { return _referrer_klass_tag; }
717 };
718
719 // tag an object
720 //
721 // This function is performance critical. If many threads attempt to tag objects
722 // around the same time then it's possible that the Mutex associated with the
723 // tag map will be a hot lock.
724 void JvmtiTagMap::set_tag(jobject object, jlong tag) {
725 MutexLocker ml(lock());
726
727 // resolve the object
728 oop o = JNIHandles::resolve_non_null(object);
729
730 // see if the object is already tagged
731 JvmtiTagHashmap* hashmap = _hashmap;
732 JvmtiTagHashmapEntry* entry = hashmap->find(o);
733
734 // if the object is not already tagged then we tag it
735 if (entry == NULL) {
736 if (tag != 0) {
737 entry = create_entry(o, tag);
738 hashmap->add(o, entry);
739 } else {
740 // no-op
741 }
742 } else {
743 // if the object is already tagged then we either update
744 // the tag (if a new tag value has been provided)
745 // or remove the object if the new tag value is 0.
746 if (tag == 0) {
747 hashmap->remove(o);
748 destroy_entry(entry);
749 } else {
750 entry->set_tag(tag);
751 }
752 }
753 }
754
755 // get the tag for an object
756 jlong JvmtiTagMap::get_tag(jobject object) {
757 MutexLocker ml(lock());
758
759 // resolve the object
760 oop o = JNIHandles::resolve_non_null(object);
761
762 return tag_for(this, o);
763 }
764
765
766 // Helper class used to describe the static or instance fields of a class.
767 // For each field it holds the field index (as defined by the JVMTI specification),
768 // the field type, and the offset.
769
770 class ClassFieldDescriptor: public CHeapObj<mtInternal> {
771 private:
772 int _field_index;
773 int _field_offset;
774 char _field_type;
775 public:
776 ClassFieldDescriptor(int index, char type, int offset) :
777 _field_index(index), _field_type(type), _field_offset(offset) {
778 }
779 int field_index() const { return _field_index; }
780 char field_type() const { return _field_type; }
781 int field_offset() const { return _field_offset; }
782 };
783
784 class ClassFieldMap: public CHeapObj<mtInternal> {
785 private:
786 enum {
787 initial_field_count = 5
788 };
789
790 // list of field descriptors
791 GrowableArray<ClassFieldDescriptor*>* _fields;
792
793 // constructor
794 ClassFieldMap();
795
796 // add a field
797 void add(int index, char type, int offset);
798
799 // returns the field count for the given class
800 static int compute_field_count(InstanceKlass* ik);
801
802 public:
803 ~ClassFieldMap();
804
805 // access
806 int field_count() { return _fields->length(); }
807 ClassFieldDescriptor* field_at(int i) { return _fields->at(i); }
808
809 // functions to create maps of static or instance fields
810 static ClassFieldMap* create_map_of_static_fields(Klass* k);
811 static ClassFieldMap* create_map_of_instance_fields(oop obj);
812 };
813
814 ClassFieldMap::ClassFieldMap() {
815 _fields = new (ResourceObj::C_HEAP, mtInternal)
816 GrowableArray<ClassFieldDescriptor*>(initial_field_count, true);
817 }
818
819 ClassFieldMap::~ClassFieldMap() {
820 for (int i=0; i<_fields->length(); i++) {
821 delete _fields->at(i);
822 }
823 delete _fields;
824 }
825
826 void ClassFieldMap::add(int index, char type, int offset) {
827 ClassFieldDescriptor* field = new ClassFieldDescriptor(index, type, offset);
828 _fields->append(field);
829 }
830
831 // Returns a heap allocated ClassFieldMap to describe the static fields
832 // of the given class.
833 //
834 ClassFieldMap* ClassFieldMap::create_map_of_static_fields(Klass* k) {
835 HandleMark hm;
836 InstanceKlass* ik = InstanceKlass::cast(k);
837
838 // create the field map
839 ClassFieldMap* field_map = new ClassFieldMap();
840
841 FilteredFieldStream f(ik, false, false);
842 int max_field_index = f.field_count()-1;
843
844 int index = 0;
845 for (FilteredFieldStream fld(ik, true, true); !fld.eos(); fld.next(), index++) {
846 // ignore instance fields
847 if (!fld.access_flags().is_static()) {
848 continue;
849 }
850 field_map->add(max_field_index - index, fld.signature()->byte_at(0), fld.offset());
851 }
852 return field_map;
853 }
854
855 // Returns a heap allocated ClassFieldMap to describe the instance fields
856 // of the given class. All instance fields are included (this means public
857 // and private fields declared in superclasses and superinterfaces too).
858 //
859 ClassFieldMap* ClassFieldMap::create_map_of_instance_fields(oop obj) {
860 HandleMark hm;
861 InstanceKlass* ik = InstanceKlass::cast(obj->klass());
862
863 // create the field map
864 ClassFieldMap* field_map = new ClassFieldMap();
865
866 FilteredFieldStream f(ik, false, false);
867
868 int max_field_index = f.field_count()-1;
869
870 int index = 0;
871 for (FilteredFieldStream fld(ik, false, false); !fld.eos(); fld.next(), index++) {
872 // ignore static fields
873 if (fld.access_flags().is_static()) {
874 continue;
875 }
876 field_map->add(max_field_index - index, fld.signature()->byte_at(0), fld.offset());
877 }
878
879 return field_map;
880 }
881
882 // Helper class used to cache a ClassFileMap for the instance fields of
883 // a cache. A JvmtiCachedClassFieldMap can be cached by an InstanceKlass during
884 // heap iteration and avoid creating a field map for each object in the heap
885 // (only need to create the map when the first instance of a class is encountered).
886 //
887 class JvmtiCachedClassFieldMap : public CHeapObj<mtInternal> {
888 private:
889 enum {
890 initial_class_count = 200
891 };
892 ClassFieldMap* _field_map;
893
894 ClassFieldMap* field_map() const { return _field_map; }
895
896 JvmtiCachedClassFieldMap(ClassFieldMap* field_map);
897 ~JvmtiCachedClassFieldMap();
898
899 static GrowableArray<InstanceKlass*>* _class_list;
900 static void add_to_class_list(InstanceKlass* ik);
901
902 public:
903 // returns the field map for a given object (returning map cached
904 // by InstanceKlass if possible
905 static ClassFieldMap* get_map_of_instance_fields(oop obj);
906
907 // removes the field map from all instanceKlasses - should be
908 // called before VM operation completes
909 static void clear_cache();
910
911 // returns the number of ClassFieldMap cached by instanceKlasses
912 static int cached_field_map_count();
913 };
914
915 GrowableArray<InstanceKlass*>* JvmtiCachedClassFieldMap::_class_list;
916
917 JvmtiCachedClassFieldMap::JvmtiCachedClassFieldMap(ClassFieldMap* field_map) {
918 _field_map = field_map;
919 }
920
921 JvmtiCachedClassFieldMap::~JvmtiCachedClassFieldMap() {
922 if (_field_map != NULL) {
923 delete _field_map;
924 }
925 }
926
927 // Marker class to ensure that the class file map cache is only used in a defined
928 // scope.
929 class ClassFieldMapCacheMark : public StackObj {
930 private:
931 static bool _is_active;
932 public:
933 ClassFieldMapCacheMark() {
934 assert(Thread::current()->is_VM_thread(), "must be VMThread");
935 assert(JvmtiCachedClassFieldMap::cached_field_map_count() == 0, "cache not empty");
936 assert(!_is_active, "ClassFieldMapCacheMark cannot be nested");
937 _is_active = true;
938 }
939 ~ClassFieldMapCacheMark() {
940 JvmtiCachedClassFieldMap::clear_cache();
941 _is_active = false;
942 }
943 static bool is_active() { return _is_active; }
944 };
945
946 bool ClassFieldMapCacheMark::_is_active;
947
948
949 // record that the given InstanceKlass is caching a field map
950 void JvmtiCachedClassFieldMap::add_to_class_list(InstanceKlass* ik) {
951 if (_class_list == NULL) {
952 _class_list = new (ResourceObj::C_HEAP, mtInternal)
953 GrowableArray<InstanceKlass*>(initial_class_count, true);
954 }
955 _class_list->push(ik);
956 }
957
958 // returns the instance field map for the given object
959 // (returns field map cached by the InstanceKlass if possible)
960 ClassFieldMap* JvmtiCachedClassFieldMap::get_map_of_instance_fields(oop obj) {
961 assert(Thread::current()->is_VM_thread(), "must be VMThread");
962 assert(ClassFieldMapCacheMark::is_active(), "ClassFieldMapCacheMark not active");
963
964 Klass* k = obj->klass();
965 InstanceKlass* ik = InstanceKlass::cast(k);
966
967 // return cached map if possible
968 JvmtiCachedClassFieldMap* cached_map = ik->jvmti_cached_class_field_map();
969 if (cached_map != NULL) {
970 assert(cached_map->field_map() != NULL, "missing field list");
971 return cached_map->field_map();
972 } else {
973 ClassFieldMap* field_map = ClassFieldMap::create_map_of_instance_fields(obj);
974 cached_map = new JvmtiCachedClassFieldMap(field_map);
975 ik->set_jvmti_cached_class_field_map(cached_map);
976 add_to_class_list(ik);
977 return field_map;
978 }
979 }
980
981 // remove the fields maps cached from all instanceKlasses
982 void JvmtiCachedClassFieldMap::clear_cache() {
983 assert(Thread::current()->is_VM_thread(), "must be VMThread");
984 if (_class_list != NULL) {
985 for (int i = 0; i < _class_list->length(); i++) {
986 InstanceKlass* ik = _class_list->at(i);
987 JvmtiCachedClassFieldMap* cached_map = ik->jvmti_cached_class_field_map();
988 assert(cached_map != NULL, "should not be NULL");
989 ik->set_jvmti_cached_class_field_map(NULL);
990 delete cached_map; // deletes the encapsulated field map
991 }
992 delete _class_list;
993 _class_list = NULL;
994 }
995 }
996
997 // returns the number of ClassFieldMap cached by instanceKlasses
998 int JvmtiCachedClassFieldMap::cached_field_map_count() {
999 return (_class_list == NULL) ? 0 : _class_list->length();
1000 }
1001
1002 // helper function to indicate if an object is filtered by its tag or class tag
1003 static inline bool is_filtered_by_heap_filter(jlong obj_tag,
1004 jlong klass_tag,
1005 int heap_filter) {
1006 // apply the heap filter
1007 if (obj_tag != 0) {
1008 // filter out tagged objects
1009 if (heap_filter & JVMTI_HEAP_FILTER_TAGGED) return true;
1010 } else {
1011 // filter out untagged objects
1012 if (heap_filter & JVMTI_HEAP_FILTER_UNTAGGED) return true;
1013 }
1014 if (klass_tag != 0) {
1015 // filter out objects with tagged classes
1016 if (heap_filter & JVMTI_HEAP_FILTER_CLASS_TAGGED) return true;
1017 } else {
1018 // filter out objects with untagged classes.
1019 if (heap_filter & JVMTI_HEAP_FILTER_CLASS_UNTAGGED) return true;
1020 }
1021 return false;
1022 }
1023
1024 // helper function to indicate if an object is filtered by a klass filter
1025 static inline bool is_filtered_by_klass_filter(oop obj, Klass* klass_filter) {
1026 if (klass_filter != NULL) {
1027 if (obj->klass() != klass_filter) {
1028 return true;
1029 }
1030 }
1031 return false;
1032 }
1033
1034 // helper function to tell if a field is a primitive field or not
1035 static inline bool is_primitive_field_type(char type) {
1036 return (type != 'L' && type != '[');
1037 }
1038
1039 // helper function to copy the value from location addr to jvalue.
1040 static inline void copy_to_jvalue(jvalue *v, address addr, jvmtiPrimitiveType value_type) {
1041 switch (value_type) {
1042 case JVMTI_PRIMITIVE_TYPE_BOOLEAN : { v->z = *(jboolean*)addr; break; }
1043 case JVMTI_PRIMITIVE_TYPE_BYTE : { v->b = *(jbyte*)addr; break; }
1044 case JVMTI_PRIMITIVE_TYPE_CHAR : { v->c = *(jchar*)addr; break; }
1045 case JVMTI_PRIMITIVE_TYPE_SHORT : { v->s = *(jshort*)addr; break; }
1046 case JVMTI_PRIMITIVE_TYPE_INT : { v->i = *(jint*)addr; break; }
1047 case JVMTI_PRIMITIVE_TYPE_LONG : { v->j = *(jlong*)addr; break; }
1048 case JVMTI_PRIMITIVE_TYPE_FLOAT : { v->f = *(jfloat*)addr; break; }
1049 case JVMTI_PRIMITIVE_TYPE_DOUBLE : { v->d = *(jdouble*)addr; break; }
1050 default: ShouldNotReachHere();
1051 }
1052 }
1053
1054 // helper function to invoke string primitive value callback
1055 // returns visit control flags
1056 static jint invoke_string_value_callback(jvmtiStringPrimitiveValueCallback cb,
1057 CallbackWrapper* wrapper,
1058 oop str,
1059 void* user_data)
1060 {
1061 assert(str->klass() == SystemDictionary::String_klass(), "not a string");
1062
1063 typeArrayOop s_value = java_lang_String::value(str);
1064
1065 // JDK-6584008: the value field may be null if a String instance is
1066 // partially constructed.
1067 if (s_value == NULL) {
1068 return 0;
1069 }
1070 // get the string value and length
1071 // (string value may be offset from the base)
1072 int s_len = java_lang_String::length(str);
1073 bool is_latin1 = java_lang_String::is_latin1(str);
1074 jchar* value;
1075 if (s_len > 0) {
1076 if (!is_latin1) {
1077 value = s_value->char_at_addr(0);
1078 } else {
1079 // Inflate latin1 encoded string to UTF16
1080 jchar* buf = NEW_C_HEAP_ARRAY(jchar, s_len, mtInternal);
1081 for (int i = 0; i < s_len; i++) {
1082 buf[i] = ((jchar) s_value->byte_at(i)) & 0xff;
1083 }
1084 value = &buf[0];
1085 }
1086 } else {
1087 // Don't use char_at_addr(0) if length is 0
1088 value = (jchar*) s_value->base(T_CHAR);
1089 }
1090
1091 // invoke the callback
1092 jint res = (*cb)(wrapper->klass_tag(),
1093 wrapper->obj_size(),
1094 wrapper->obj_tag_p(),
1095 value,
1096 (jint)s_len,
1097 user_data);
1098
1099 if (is_latin1 && s_len > 0) {
1100 FREE_C_HEAP_ARRAY(jchar, value);
1101 }
1102 return res;
1103 }
1104
1105 // helper function to invoke string primitive value callback
1106 // returns visit control flags
1107 static jint invoke_array_primitive_value_callback(jvmtiArrayPrimitiveValueCallback cb,
1108 CallbackWrapper* wrapper,
1109 oop obj,
1110 void* user_data)
1111 {
1112 assert(obj->is_typeArray(), "not a primitive array");
1113
1114 // get base address of first element
1115 typeArrayOop array = typeArrayOop(obj);
1116 BasicType type = TypeArrayKlass::cast(array->klass())->element_type();
1117 void* elements = array->base(type);
1118
1119 // jvmtiPrimitiveType is defined so this mapping is always correct
1120 jvmtiPrimitiveType elem_type = (jvmtiPrimitiveType)type2char(type);
1121
1122 return (*cb)(wrapper->klass_tag(),
1123 wrapper->obj_size(),
1124 wrapper->obj_tag_p(),
1125 (jint)array->length(),
1126 elem_type,
1127 elements,
1128 user_data);
1129 }
1130
1131 // helper function to invoke the primitive field callback for all static fields
1132 // of a given class
1133 static jint invoke_primitive_field_callback_for_static_fields
1134 (CallbackWrapper* wrapper,
1135 oop obj,
1136 jvmtiPrimitiveFieldCallback cb,
1137 void* user_data)
1138 {
1139 // for static fields only the index will be set
1140 static jvmtiHeapReferenceInfo reference_info = { 0 };
1141
1142 assert(obj->klass() == SystemDictionary::Class_klass(), "not a class");
1143 if (java_lang_Class::is_primitive(obj)) {
1144 return 0;
1145 }
1146 Klass* klass = java_lang_Class::as_Klass(obj);
1147
1148 // ignore classes for object and type arrays
1149 if (!klass->is_instance_klass()) {
1150 return 0;
1151 }
1152
1153 // ignore classes which aren't linked yet
1154 InstanceKlass* ik = InstanceKlass::cast(klass);
1155 if (!ik->is_linked()) {
1156 return 0;
1157 }
1158
1159 // get the field map
1160 ClassFieldMap* field_map = ClassFieldMap::create_map_of_static_fields(klass);
1161
1162 // invoke the callback for each static primitive field
1163 for (int i=0; i<field_map->field_count(); i++) {
1164 ClassFieldDescriptor* field = field_map->field_at(i);
1165
1166 // ignore non-primitive fields
1167 char type = field->field_type();
1168 if (!is_primitive_field_type(type)) {
1169 continue;
1170 }
1171 // one-to-one mapping
1172 jvmtiPrimitiveType value_type = (jvmtiPrimitiveType)type;
1173
1174 // get offset and field value
1175 int offset = field->field_offset();
1176 address addr = (address)klass->java_mirror() + offset;
1177 jvalue value;
1178 copy_to_jvalue(&value, addr, value_type);
1179
1180 // field index
1181 reference_info.field.index = field->field_index();
1182
1183 // invoke the callback
1184 jint res = (*cb)(JVMTI_HEAP_REFERENCE_STATIC_FIELD,
1185 &reference_info,
1186 wrapper->klass_tag(),
1187 wrapper->obj_tag_p(),
1188 value,
1189 value_type,
1190 user_data);
1191 if (res & JVMTI_VISIT_ABORT) {
1192 delete field_map;
1193 return res;
1194 }
1195 }
1196
1197 delete field_map;
1198 return 0;
1199 }
1200
1201 // helper function to invoke the primitive field callback for all instance fields
1202 // of a given object
1203 static jint invoke_primitive_field_callback_for_instance_fields(
1204 CallbackWrapper* wrapper,
1205 oop obj,
1206 jvmtiPrimitiveFieldCallback cb,
1207 void* user_data)
1208 {
1209 // for instance fields only the index will be set
1210 static jvmtiHeapReferenceInfo reference_info = { 0 };
1211
1212 // get the map of the instance fields
1213 ClassFieldMap* fields = JvmtiCachedClassFieldMap::get_map_of_instance_fields(obj);
1214
1215 // invoke the callback for each instance primitive field
1216 for (int i=0; i<fields->field_count(); i++) {
1217 ClassFieldDescriptor* field = fields->field_at(i);
1218
1219 // ignore non-primitive fields
1220 char type = field->field_type();
1221 if (!is_primitive_field_type(type)) {
1222 continue;
1223 }
1224 // one-to-one mapping
1225 jvmtiPrimitiveType value_type = (jvmtiPrimitiveType)type;
1226
1227 // get offset and field value
1228 int offset = field->field_offset();
1229 address addr = (address)obj + offset;
1230 jvalue value;
1231 copy_to_jvalue(&value, addr, value_type);
1232
1233 // field index
1234 reference_info.field.index = field->field_index();
1235
1236 // invoke the callback
1237 jint res = (*cb)(JVMTI_HEAP_REFERENCE_FIELD,
1238 &reference_info,
1239 wrapper->klass_tag(),
1240 wrapper->obj_tag_p(),
1241 value,
1242 value_type,
1243 user_data);
1244 if (res & JVMTI_VISIT_ABORT) {
1245 return res;
1246 }
1247 }
1248 return 0;
1249 }
1250
1251
1252 // VM operation to iterate over all objects in the heap (both reachable
1253 // and unreachable)
1254 class VM_HeapIterateOperation: public VM_Operation {
1255 private:
1256 ObjectClosure* _blk;
1257 public:
1258 VM_HeapIterateOperation(ObjectClosure* blk) { _blk = blk; }
1259
1260 VMOp_Type type() const { return VMOp_HeapIterateOperation; }
1261 void doit() {
1262 // allows class files maps to be cached during iteration
1263 ClassFieldMapCacheMark cm;
1264
1265 // make sure that heap is parsable (fills TLABs with filler objects)
1266 Universe::heap()->ensure_parsability(false); // no need to retire TLABs
1267
1268 // Verify heap before iteration - if the heap gets corrupted then
1269 // JVMTI's IterateOverHeap will crash.
1270 if (VerifyBeforeIteration) {
1271 Universe::verify();
1272 }
1273
1274 // do the iteration
1275 // If this operation encounters a bad object when using CMS,
1276 // consider using safe_object_iterate() which avoids perm gen
1277 // objects that may contain bad references.
1278 Universe::heap()->object_iterate(_blk);
1279 }
1280
1281 };
1282
1283
1284 // An ObjectClosure used to support the deprecated IterateOverHeap and
1285 // IterateOverInstancesOfClass functions
1286 class IterateOverHeapObjectClosure: public ObjectClosure {
1287 private:
1288 JvmtiTagMap* _tag_map;
1289 Klass* _klass;
1290 jvmtiHeapObjectFilter _object_filter;
1291 jvmtiHeapObjectCallback _heap_object_callback;
1292 const void* _user_data;
1293
1294 // accessors
1295 JvmtiTagMap* tag_map() const { return _tag_map; }
1296 jvmtiHeapObjectFilter object_filter() const { return _object_filter; }
1297 jvmtiHeapObjectCallback object_callback() const { return _heap_object_callback; }
1298 Klass* klass() const { return _klass; }
1299 const void* user_data() const { return _user_data; }
1300
1301 // indicates if iteration has been aborted
1302 bool _iteration_aborted;
1303 bool is_iteration_aborted() const { return _iteration_aborted; }
1304 void set_iteration_aborted(bool aborted) { _iteration_aborted = aborted; }
1305
1306 public:
1307 IterateOverHeapObjectClosure(JvmtiTagMap* tag_map,
1308 Klass* klass,
1309 jvmtiHeapObjectFilter object_filter,
1310 jvmtiHeapObjectCallback heap_object_callback,
1311 const void* user_data) :
1312 _tag_map(tag_map),
1313 _klass(klass),
1314 _object_filter(object_filter),
1315 _heap_object_callback(heap_object_callback),
1316 _user_data(user_data),
1317 _iteration_aborted(false)
1318 {
1319 }
1320
1321 void do_object(oop o);
1322 };
1323
1324 // invoked for each object in the heap
1325 void IterateOverHeapObjectClosure::do_object(oop o) {
1326 // check if iteration has been halted
1327 if (is_iteration_aborted()) return;
1328
1329 // ignore any objects that aren't visible to profiler
1330 if (!ServiceUtil::visible_oop(o)) return;
1331
1332 // instanceof check when filtering by klass
1333 if (klass() != NULL && !o->is_a(klass())) {
1334 return;
1335 }
1336 // prepare for the calllback
1337 CallbackWrapper wrapper(tag_map(), o);
1338
1339 // if the object is tagged and we're only interested in untagged objects
1340 // then don't invoke the callback. Similiarly, if the object is untagged
1341 // and we're only interested in tagged objects we skip the callback.
1342 if (wrapper.obj_tag() != 0) {
1343 if (object_filter() == JVMTI_HEAP_OBJECT_UNTAGGED) return;
1344 } else {
1345 if (object_filter() == JVMTI_HEAP_OBJECT_TAGGED) return;
1346 }
1347
1348 // invoke the agent's callback
1349 jvmtiIterationControl control = (*object_callback())(wrapper.klass_tag(),
1350 wrapper.obj_size(),
1351 wrapper.obj_tag_p(),
1352 (void*)user_data());
1353 if (control == JVMTI_ITERATION_ABORT) {
1354 set_iteration_aborted(true);
1355 }
1356 }
1357
1358 // An ObjectClosure used to support the IterateThroughHeap function
1359 class IterateThroughHeapObjectClosure: public ObjectClosure {
1360 private:
1361 JvmtiTagMap* _tag_map;
1362 Klass* _klass;
1363 int _heap_filter;
1364 const jvmtiHeapCallbacks* _callbacks;
1365 const void* _user_data;
1366
1367 // accessor functions
1368 JvmtiTagMap* tag_map() const { return _tag_map; }
1369 int heap_filter() const { return _heap_filter; }
1370 const jvmtiHeapCallbacks* callbacks() const { return _callbacks; }
1371 Klass* klass() const { return _klass; }
1372 const void* user_data() const { return _user_data; }
1373
1374 // indicates if the iteration has been aborted
1375 bool _iteration_aborted;
1376 bool is_iteration_aborted() const { return _iteration_aborted; }
1377
1378 // used to check the visit control flags. If the abort flag is set
1379 // then we set the iteration aborted flag so that the iteration completes
1380 // without processing any further objects
1381 bool check_flags_for_abort(jint flags) {
1382 bool is_abort = (flags & JVMTI_VISIT_ABORT) != 0;
1383 if (is_abort) {
1384 _iteration_aborted = true;
1385 }
1386 return is_abort;
1387 }
1388
1389 public:
1390 IterateThroughHeapObjectClosure(JvmtiTagMap* tag_map,
1391 Klass* klass,
1392 int heap_filter,
1393 const jvmtiHeapCallbacks* heap_callbacks,
1394 const void* user_data) :
1395 _tag_map(tag_map),
1396 _klass(klass),
1397 _heap_filter(heap_filter),
1398 _callbacks(heap_callbacks),
1399 _user_data(user_data),
1400 _iteration_aborted(false)
1401 {
1402 }
1403
1404 void do_object(oop o);
1405 };
1406
1407 // invoked for each object in the heap
1408 void IterateThroughHeapObjectClosure::do_object(oop obj) {
1409 // check if iteration has been halted
1410 if (is_iteration_aborted()) return;
1411
1412 // ignore any objects that aren't visible to profiler
1413 if (!ServiceUtil::visible_oop(obj)) return;
1414
1415 // apply class filter
1416 if (is_filtered_by_klass_filter(obj, klass())) return;
1417
1418 // prepare for callback
1419 CallbackWrapper wrapper(tag_map(), obj);
1420
1421 // check if filtered by the heap filter
1422 if (is_filtered_by_heap_filter(wrapper.obj_tag(), wrapper.klass_tag(), heap_filter())) {
1423 return;
1424 }
1425
1426 // for arrays we need the length, otherwise -1
1427 bool is_array = obj->is_array();
1428 int len = is_array ? arrayOop(obj)->length() : -1;
1429
1430 // invoke the object callback (if callback is provided)
1431 if (callbacks()->heap_iteration_callback != NULL) {
1432 jvmtiHeapIterationCallback cb = callbacks()->heap_iteration_callback;
1433 jint res = (*cb)(wrapper.klass_tag(),
1434 wrapper.obj_size(),
1435 wrapper.obj_tag_p(),
1436 (jint)len,
1437 (void*)user_data());
1438 if (check_flags_for_abort(res)) return;
1439 }
1440
1441 // for objects and classes we report primitive fields if callback provided
1442 if (callbacks()->primitive_field_callback != NULL && obj->is_instance()) {
1443 jint res;
1444 jvmtiPrimitiveFieldCallback cb = callbacks()->primitive_field_callback;
1445 if (obj->klass() == SystemDictionary::Class_klass()) {
1446 res = invoke_primitive_field_callback_for_static_fields(&wrapper,
1447 obj,
1448 cb,
1449 (void*)user_data());
1450 } else {
1451 res = invoke_primitive_field_callback_for_instance_fields(&wrapper,
1452 obj,
1453 cb,
1454 (void*)user_data());
1455 }
1456 if (check_flags_for_abort(res)) return;
1457 }
1458
1459 // string callback
1460 if (!is_array &&
1461 callbacks()->string_primitive_value_callback != NULL &&
1462 obj->klass() == SystemDictionary::String_klass()) {
1463 jint res = invoke_string_value_callback(
1464 callbacks()->string_primitive_value_callback,
1465 &wrapper,
1466 obj,
1467 (void*)user_data() );
1468 if (check_flags_for_abort(res)) return;
1469 }
1470
1471 // array callback
1472 if (is_array &&
1473 callbacks()->array_primitive_value_callback != NULL &&
1474 obj->is_typeArray()) {
1475 jint res = invoke_array_primitive_value_callback(
1476 callbacks()->array_primitive_value_callback,
1477 &wrapper,
1478 obj,
1479 (void*)user_data() );
1480 if (check_flags_for_abort(res)) return;
1481 }
1482 };
1483
1484
1485 // Deprecated function to iterate over all objects in the heap
1486 void JvmtiTagMap::iterate_over_heap(jvmtiHeapObjectFilter object_filter,
1487 Klass* klass,
1488 jvmtiHeapObjectCallback heap_object_callback,
1489 const void* user_data)
1490 {
1491 MutexLocker ml(Heap_lock);
1492 IterateOverHeapObjectClosure blk(this,
1493 klass,
1494 object_filter,
1495 heap_object_callback,
1496 user_data);
1497 VM_HeapIterateOperation op(&blk);
1498 VMThread::execute(&op);
1499 }
1500
1501
1502 // Iterates over all objects in the heap
1503 void JvmtiTagMap::iterate_through_heap(jint heap_filter,
1504 Klass* klass,
1505 const jvmtiHeapCallbacks* callbacks,
1506 const void* user_data)
1507 {
1508 MutexLocker ml(Heap_lock);
1509 IterateThroughHeapObjectClosure blk(this,
1510 klass,
1511 heap_filter,
1512 callbacks,
1513 user_data);
1514 VM_HeapIterateOperation op(&blk);
1515 VMThread::execute(&op);
1516 }
1517
1518 // support class for get_objects_with_tags
1519
1520 class TagObjectCollector : public JvmtiTagHashmapEntryClosure {
1521 private:
1522 JvmtiEnv* _env;
1523 jlong* _tags;
1524 jint _tag_count;
1525
1526 GrowableArray<jobject>* _object_results; // collected objects (JNI weak refs)
1527 GrowableArray<uint64_t>* _tag_results; // collected tags
1528
1529 public:
1530 TagObjectCollector(JvmtiEnv* env, const jlong* tags, jint tag_count) {
1531 _env = env;
1532 _tags = (jlong*)tags;
1533 _tag_count = tag_count;
1534 _object_results = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<jobject>(1,true);
1535 _tag_results = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<uint64_t>(1,true);
1536 }
1537
1538 ~TagObjectCollector() {
1539 delete _object_results;
1540 delete _tag_results;
1541 }
1542
1543 // for each tagged object check if the tag value matches
1544 // - if it matches then we create a JNI local reference to the object
1545 // and record the reference and tag value.
1546 //
1547 void do_entry(JvmtiTagHashmapEntry* entry) {
1548 for (int i=0; i<_tag_count; i++) {
1549 if (_tags[i] == entry->tag()) {
1550 // The reference in this tag map could be the only (implicitly weak)
1551 // reference to that object. If we hand it out, we need to keep it live wrt
1552 // SATB marking similar to other j.l.ref.Reference referents. This is
1553 // achieved by using a phantom load in the object() accessor.
1554 oop o = entry->object();
1555 assert(o != NULL && Universe::heap()->is_in_reserved(o), "sanity check");
1556 jobject ref = JNIHandles::make_local(JavaThread::current(), o);
1557 _object_results->append(ref);
1558 _tag_results->append((uint64_t)entry->tag());
1559 }
1560 }
1561 }
1562
1563 // return the results from the collection
1564 //
1565 jvmtiError result(jint* count_ptr, jobject** object_result_ptr, jlong** tag_result_ptr) {
1566 jvmtiError error;
1567 int count = _object_results->length();
1568 assert(count >= 0, "sanity check");
1569
1570 // if object_result_ptr is not NULL then allocate the result and copy
1571 // in the object references.
1572 if (object_result_ptr != NULL) {
1573 error = _env->Allocate(count * sizeof(jobject), (unsigned char**)object_result_ptr);
1574 if (error != JVMTI_ERROR_NONE) {
1575 return error;
1576 }
1577 for (int i=0; i<count; i++) {
1578 (*object_result_ptr)[i] = _object_results->at(i);
1579 }
1580 }
1581
1582 // if tag_result_ptr is not NULL then allocate the result and copy
1583 // in the tag values.
1584 if (tag_result_ptr != NULL) {
1585 error = _env->Allocate(count * sizeof(jlong), (unsigned char**)tag_result_ptr);
1586 if (error != JVMTI_ERROR_NONE) {
1587 if (object_result_ptr != NULL) {
1588 _env->Deallocate((unsigned char*)object_result_ptr);
1589 }
1590 return error;
1591 }
1592 for (int i=0; i<count; i++) {
1593 (*tag_result_ptr)[i] = (jlong)_tag_results->at(i);
1594 }
1595 }
1596
1597 *count_ptr = count;
1598 return JVMTI_ERROR_NONE;
1599 }
1600 };
1601
1602 // return the list of objects with the specified tags
1603 jvmtiError JvmtiTagMap::get_objects_with_tags(const jlong* tags,
1604 jint count, jint* count_ptr, jobject** object_result_ptr, jlong** tag_result_ptr) {
1605
1606 TagObjectCollector collector(env(), tags, count);
1607 {
1608 // iterate over all tagged objects
1609 MutexLocker ml(lock());
1610 entry_iterate(&collector);
1611 }
1612 return collector.result(count_ptr, object_result_ptr, tag_result_ptr);
1613 }
1614
1615
1616 // ObjectMarker is used to support the marking objects when walking the
1617 // heap.
1618 //
1619 // This implementation uses the existing mark bits in an object for
1620 // marking. Objects that are marked must later have their headers restored.
1621 // As most objects are unlocked and don't have their identity hash computed
1622 // we don't have to save their headers. Instead we save the headers that
1623 // are "interesting". Later when the headers are restored this implementation
1624 // restores all headers to their initial value and then restores the few
1625 // objects that had interesting headers.
1626 //
1627 // Future work: This implementation currently uses growable arrays to save
1628 // the oop and header of interesting objects. As an optimization we could
1629 // use the same technique as the GC and make use of the unused area
1630 // between top() and end().
1631 //
1632
1633 // An ObjectClosure used to restore the mark bits of an object
1634 class RestoreMarksClosure : public ObjectClosure {
1635 public:
1636 void do_object(oop o) {
1637 if (o != NULL) {
1638 markOop mark = o->mark();
1639 if (mark->is_marked()) {
1640 o->init_mark();
1641 }
1642 }
1643 }
1644 };
1645
1646 // ObjectMarker provides the mark and visited functions
1647 class ObjectMarker : AllStatic {
1648 private:
1649 // saved headers
1650 static GrowableArray<oop>* _saved_oop_stack;
1651 static GrowableArray<markOop>* _saved_mark_stack;
1652 static bool _needs_reset; // do we need to reset mark bits?
1653
1654 public:
1655 static void init(); // initialize
1656 static void done(); // clean-up
1657
1658 static inline void mark(oop o); // mark an object
1659 static inline bool visited(oop o); // check if object has been visited
1660
1661 static inline bool needs_reset() { return _needs_reset; }
1662 static inline void set_needs_reset(bool v) { _needs_reset = v; }
1663 };
1664
1665 GrowableArray<oop>* ObjectMarker::_saved_oop_stack = NULL;
1666 GrowableArray<markOop>* ObjectMarker::_saved_mark_stack = NULL;
1667 bool ObjectMarker::_needs_reset = true; // need to reset mark bits by default
1668
1669 // initialize ObjectMarker - prepares for object marking
1670 void ObjectMarker::init() {
1671 assert(Thread::current()->is_VM_thread(), "must be VMThread");
1672
1673 // prepare heap for iteration
1674 Universe::heap()->ensure_parsability(false); // no need to retire TLABs
1675
1676 // create stacks for interesting headers
1677 _saved_mark_stack = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<markOop>(4000, true);
1678 _saved_oop_stack = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<oop>(4000, true);
1679
1680 if (UseBiasedLocking) {
1681 BiasedLocking::preserve_marks();
1682 }
1683 }
1684
1685 // Object marking is done so restore object headers
1686 void ObjectMarker::done() {
1687 // iterate over all objects and restore the mark bits to
1688 // their initial value
1689 RestoreMarksClosure blk;
1690 if (needs_reset()) {
1691 Universe::heap()->object_iterate(&blk);
1692 } else {
1693 // We don't need to reset mark bits on this call, but reset the
1694 // flag to the default for the next call.
1695 set_needs_reset(true);
1696 }
1697
1698 // now restore the interesting headers
1699 for (int i = 0; i < _saved_oop_stack->length(); i++) {
1700 oop o = _saved_oop_stack->at(i);
1701 markOop mark = _saved_mark_stack->at(i);
1702 o->set_mark(mark);
1703 }
1704
1705 if (UseBiasedLocking) {
1706 BiasedLocking::restore_marks();
1707 }
1708
1709 // free the stacks
1710 delete _saved_oop_stack;
1711 delete _saved_mark_stack;
1712 }
1713
1714 // mark an object
1715 inline void ObjectMarker::mark(oop o) {
1716 assert(Universe::heap()->is_in(o), "sanity check");
1717 assert(!o->mark()->is_marked(), "should only mark an object once");
1718
1719 // object's mark word
1720 markOop mark = o->mark();
1721
1722 if (mark->must_be_preserved(o)) {
1723 _saved_mark_stack->push(mark);
1724 _saved_oop_stack->push(o);
1725 }
1726
1727 // mark the object
1728 o->set_mark(markOopDesc::prototype()->set_marked());
1729 }
1730
1731 // return true if object is marked
1732 inline bool ObjectMarker::visited(oop o) {
1733 return o->mark()->is_marked();
1734 }
1735
1736 // Stack allocated class to help ensure that ObjectMarker is used
1737 // correctly. Constructor initializes ObjectMarker, destructor calls
1738 // ObjectMarker's done() function to restore object headers.
1739 class ObjectMarkerController : public StackObj {
1740 public:
1741 ObjectMarkerController() {
1742 ObjectMarker::init();
1743 }
1744 ~ObjectMarkerController() {
1745 ObjectMarker::done();
1746 }
1747 };
1748
1749
1750 // helper to map a jvmtiHeapReferenceKind to an old style jvmtiHeapRootKind
1751 // (not performance critical as only used for roots)
1752 static jvmtiHeapRootKind toJvmtiHeapRootKind(jvmtiHeapReferenceKind kind) {
1753 switch (kind) {
1754 case JVMTI_HEAP_REFERENCE_JNI_GLOBAL: return JVMTI_HEAP_ROOT_JNI_GLOBAL;
1755 case JVMTI_HEAP_REFERENCE_SYSTEM_CLASS: return JVMTI_HEAP_ROOT_SYSTEM_CLASS;
1756 case JVMTI_HEAP_REFERENCE_MONITOR: return JVMTI_HEAP_ROOT_MONITOR;
1757 case JVMTI_HEAP_REFERENCE_STACK_LOCAL: return JVMTI_HEAP_ROOT_STACK_LOCAL;
1758 case JVMTI_HEAP_REFERENCE_JNI_LOCAL: return JVMTI_HEAP_ROOT_JNI_LOCAL;
1759 case JVMTI_HEAP_REFERENCE_THREAD: return JVMTI_HEAP_ROOT_THREAD;
1760 case JVMTI_HEAP_REFERENCE_OTHER: return JVMTI_HEAP_ROOT_OTHER;
1761 default: ShouldNotReachHere(); return JVMTI_HEAP_ROOT_OTHER;
1762 }
1763 }
1764
1765 // Base class for all heap walk contexts. The base class maintains a flag
1766 // to indicate if the context is valid or not.
1767 class HeapWalkContext {
1768 private:
1769 bool _valid;
1770 public:
1771 HeapWalkContext(bool valid) { _valid = valid; }
1772 void invalidate() { _valid = false; }
1773 bool is_valid() const { return _valid; }
1774 };
1775
1776 // A basic heap walk context for the deprecated heap walking functions.
1777 // The context for a basic heap walk are the callbacks and fields used by
1778 // the referrer caching scheme.
1779 class BasicHeapWalkContext: public HeapWalkContext {
1780 private:
1781 jvmtiHeapRootCallback _heap_root_callback;
1782 jvmtiStackReferenceCallback _stack_ref_callback;
1783 jvmtiObjectReferenceCallback _object_ref_callback;
1784
1785 // used for caching
1786 oop _last_referrer;
1787 jlong _last_referrer_tag;
1788
1789 public:
1790 BasicHeapWalkContext() : HeapWalkContext(false) { }
1791
1792 BasicHeapWalkContext(jvmtiHeapRootCallback heap_root_callback,
1793 jvmtiStackReferenceCallback stack_ref_callback,
1794 jvmtiObjectReferenceCallback object_ref_callback) :
1795 HeapWalkContext(true),
1796 _heap_root_callback(heap_root_callback),
1797 _stack_ref_callback(stack_ref_callback),
1798 _object_ref_callback(object_ref_callback),
1799 _last_referrer(NULL),
1800 _last_referrer_tag(0) {
1801 }
1802
1803 // accessors
1804 jvmtiHeapRootCallback heap_root_callback() const { return _heap_root_callback; }
1805 jvmtiStackReferenceCallback stack_ref_callback() const { return _stack_ref_callback; }
1806 jvmtiObjectReferenceCallback object_ref_callback() const { return _object_ref_callback; }
1807
1808 oop last_referrer() const { return _last_referrer; }
1809 void set_last_referrer(oop referrer) { _last_referrer = referrer; }
1810 jlong last_referrer_tag() const { return _last_referrer_tag; }
1811 void set_last_referrer_tag(jlong value) { _last_referrer_tag = value; }
1812 };
1813
1814 // The advanced heap walk context for the FollowReferences functions.
1815 // The context is the callbacks, and the fields used for filtering.
1816 class AdvancedHeapWalkContext: public HeapWalkContext {
1817 private:
1818 jint _heap_filter;
1819 Klass* _klass_filter;
1820 const jvmtiHeapCallbacks* _heap_callbacks;
1821
1822 public:
1823 AdvancedHeapWalkContext() : HeapWalkContext(false) { }
1824
1825 AdvancedHeapWalkContext(jint heap_filter,
1826 Klass* klass_filter,
1827 const jvmtiHeapCallbacks* heap_callbacks) :
1828 HeapWalkContext(true),
1829 _heap_filter(heap_filter),
1830 _klass_filter(klass_filter),
1831 _heap_callbacks(heap_callbacks) {
1832 }
1833
1834 // accessors
1835 jint heap_filter() const { return _heap_filter; }
1836 Klass* klass_filter() const { return _klass_filter; }
1837
1838 const jvmtiHeapReferenceCallback heap_reference_callback() const {
1839 return _heap_callbacks->heap_reference_callback;
1840 };
1841 const jvmtiPrimitiveFieldCallback primitive_field_callback() const {
1842 return _heap_callbacks->primitive_field_callback;
1843 }
1844 const jvmtiArrayPrimitiveValueCallback array_primitive_value_callback() const {
1845 return _heap_callbacks->array_primitive_value_callback;
1846 }
1847 const jvmtiStringPrimitiveValueCallback string_primitive_value_callback() const {
1848 return _heap_callbacks->string_primitive_value_callback;
1849 }
1850 };
1851
1852 // The CallbackInvoker is a class with static functions that the heap walk can call
1853 // into to invoke callbacks. It works in one of two modes. The "basic" mode is
1854 // used for the deprecated IterateOverReachableObjects functions. The "advanced"
1855 // mode is for the newer FollowReferences function which supports a lot of
1856 // additional callbacks.
1857 class CallbackInvoker : AllStatic {
1858 private:
1859 // heap walk styles
1860 enum { basic, advanced };
1861 static int _heap_walk_type;
1862 static bool is_basic_heap_walk() { return _heap_walk_type == basic; }
1863 static bool is_advanced_heap_walk() { return _heap_walk_type == advanced; }
1864
1865 // context for basic style heap walk
1866 static BasicHeapWalkContext _basic_context;
1867 static BasicHeapWalkContext* basic_context() {
1868 assert(_basic_context.is_valid(), "invalid");
1869 return &_basic_context;
1870 }
1871
1872 // context for advanced style heap walk
1873 static AdvancedHeapWalkContext _advanced_context;
1874 static AdvancedHeapWalkContext* advanced_context() {
1875 assert(_advanced_context.is_valid(), "invalid");
1876 return &_advanced_context;
1877 }
1878
1879 // context needed for all heap walks
1880 static JvmtiTagMap* _tag_map;
1881 static const void* _user_data;
1882 static GrowableArray<oop>* _visit_stack;
1883
1884 // accessors
1885 static JvmtiTagMap* tag_map() { return _tag_map; }
1886 static const void* user_data() { return _user_data; }
1887 static GrowableArray<oop>* visit_stack() { return _visit_stack; }
1888
1889 // if the object hasn't been visited then push it onto the visit stack
1890 // so that it will be visited later
1891 static inline bool check_for_visit(oop obj) {
1892 if (!ObjectMarker::visited(obj)) visit_stack()->push(obj);
1893 return true;
1894 }
1895
1896 // invoke basic style callbacks
1897 static inline bool invoke_basic_heap_root_callback
1898 (jvmtiHeapRootKind root_kind, oop obj);
1899 static inline bool invoke_basic_stack_ref_callback
1900 (jvmtiHeapRootKind root_kind, jlong thread_tag, jint depth, jmethodID method,
1901 int slot, oop obj);
1902 static inline bool invoke_basic_object_reference_callback
1903 (jvmtiObjectReferenceKind ref_kind, oop referrer, oop referree, jint index);
1904
1905 // invoke advanced style callbacks
1906 static inline bool invoke_advanced_heap_root_callback
1907 (jvmtiHeapReferenceKind ref_kind, oop obj);
1908 static inline bool invoke_advanced_stack_ref_callback
1909 (jvmtiHeapReferenceKind ref_kind, jlong thread_tag, jlong tid, int depth,
1910 jmethodID method, jlocation bci, jint slot, oop obj);
1911 static inline bool invoke_advanced_object_reference_callback
1912 (jvmtiHeapReferenceKind ref_kind, oop referrer, oop referree, jint index);
1913
1914 // used to report the value of primitive fields
1915 static inline bool report_primitive_field
1916 (jvmtiHeapReferenceKind ref_kind, oop obj, jint index, address addr, char type);
1917
1918 public:
1919 // initialize for basic mode
1920 static void initialize_for_basic_heap_walk(JvmtiTagMap* tag_map,
1921 GrowableArray<oop>* visit_stack,
1922 const void* user_data,
1923 BasicHeapWalkContext context);
1924
1925 // initialize for advanced mode
1926 static void initialize_for_advanced_heap_walk(JvmtiTagMap* tag_map,
1927 GrowableArray<oop>* visit_stack,
1928 const void* user_data,
1929 AdvancedHeapWalkContext context);
1930
1931 // functions to report roots
1932 static inline bool report_simple_root(jvmtiHeapReferenceKind kind, oop o);
1933 static inline bool report_jni_local_root(jlong thread_tag, jlong tid, jint depth,
1934 jmethodID m, oop o);
1935 static inline bool report_stack_ref_root(jlong thread_tag, jlong tid, jint depth,
1936 jmethodID method, jlocation bci, jint slot, oop o);
1937
1938 // functions to report references
1939 static inline bool report_array_element_reference(oop referrer, oop referree, jint index);
1940 static inline bool report_class_reference(oop referrer, oop referree);
1941 static inline bool report_class_loader_reference(oop referrer, oop referree);
1942 static inline bool report_signers_reference(oop referrer, oop referree);
1943 static inline bool report_protection_domain_reference(oop referrer, oop referree);
1944 static inline bool report_superclass_reference(oop referrer, oop referree);
1945 static inline bool report_interface_reference(oop referrer, oop referree);
1946 static inline bool report_static_field_reference(oop referrer, oop referree, jint slot);
1947 static inline bool report_field_reference(oop referrer, oop referree, jint slot);
1948 static inline bool report_constant_pool_reference(oop referrer, oop referree, jint index);
1949 static inline bool report_primitive_array_values(oop array);
1950 static inline bool report_string_value(oop str);
1951 static inline bool report_primitive_instance_field(oop o, jint index, address value, char type);
1952 static inline bool report_primitive_static_field(oop o, jint index, address value, char type);
1953 };
1954
1955 // statics
1956 int CallbackInvoker::_heap_walk_type;
1957 BasicHeapWalkContext CallbackInvoker::_basic_context;
1958 AdvancedHeapWalkContext CallbackInvoker::_advanced_context;
1959 JvmtiTagMap* CallbackInvoker::_tag_map;
1960 const void* CallbackInvoker::_user_data;
1961 GrowableArray<oop>* CallbackInvoker::_visit_stack;
1962
1963 // initialize for basic heap walk (IterateOverReachableObjects et al)
1964 void CallbackInvoker::initialize_for_basic_heap_walk(JvmtiTagMap* tag_map,
1965 GrowableArray<oop>* visit_stack,
1966 const void* user_data,
1967 BasicHeapWalkContext context) {
1968 _tag_map = tag_map;
1969 _visit_stack = visit_stack;
1970 _user_data = user_data;
1971 _basic_context = context;
1972 _advanced_context.invalidate(); // will trigger assertion if used
1973 _heap_walk_type = basic;
1974 }
1975
1976 // initialize for advanced heap walk (FollowReferences)
1977 void CallbackInvoker::initialize_for_advanced_heap_walk(JvmtiTagMap* tag_map,
1978 GrowableArray<oop>* visit_stack,
1979 const void* user_data,
1980 AdvancedHeapWalkContext context) {
1981 _tag_map = tag_map;
1982 _visit_stack = visit_stack;
1983 _user_data = user_data;
1984 _advanced_context = context;
1985 _basic_context.invalidate(); // will trigger assertion if used
1986 _heap_walk_type = advanced;
1987 }
1988
1989
1990 // invoke basic style heap root callback
1991 inline bool CallbackInvoker::invoke_basic_heap_root_callback(jvmtiHeapRootKind root_kind, oop obj) {
1992 assert(ServiceUtil::visible_oop(obj), "checking");
1993
1994 // if we heap roots should be reported
1995 jvmtiHeapRootCallback cb = basic_context()->heap_root_callback();
1996 if (cb == NULL) {
1997 return check_for_visit(obj);
1998 }
1999
2000 CallbackWrapper wrapper(tag_map(), obj);
2001 jvmtiIterationControl control = (*cb)(root_kind,
2002 wrapper.klass_tag(),
2003 wrapper.obj_size(),
2004 wrapper.obj_tag_p(),
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 stack ref callback
2015 inline bool CallbackInvoker::invoke_basic_stack_ref_callback(jvmtiHeapRootKind root_kind,
2016 jlong thread_tag,
2017 jint depth,
2018 jmethodID method,
2019 int slot,
2020 oop obj) {
2021 assert(ServiceUtil::visible_oop(obj), "checking");
2022
2023 // if we stack refs should be reported
2024 jvmtiStackReferenceCallback cb = basic_context()->stack_ref_callback();
2025 if (cb == NULL) {
2026 return check_for_visit(obj);
2027 }
2028
2029 CallbackWrapper wrapper(tag_map(), obj);
2030 jvmtiIterationControl control = (*cb)(root_kind,
2031 wrapper.klass_tag(),
2032 wrapper.obj_size(),
2033 wrapper.obj_tag_p(),
2034 thread_tag,
2035 depth,
2036 method,
2037 slot,
2038 (void*)user_data());
2039 // push root to visit stack when following references
2040 if (control == JVMTI_ITERATION_CONTINUE &&
2041 basic_context()->object_ref_callback() != NULL) {
2042 visit_stack()->push(obj);
2043 }
2044 return control != JVMTI_ITERATION_ABORT;
2045 }
2046
2047 // invoke basic style object reference callback
2048 inline bool CallbackInvoker::invoke_basic_object_reference_callback(jvmtiObjectReferenceKind ref_kind,
2049 oop referrer,
2050 oop referree,
2051 jint index) {
2052
2053 assert(ServiceUtil::visible_oop(referrer), "checking");
2054 assert(ServiceUtil::visible_oop(referree), "checking");
2055
2056 BasicHeapWalkContext* context = basic_context();
2057
2058 // callback requires the referrer's tag. If it's the same referrer
2059 // as the last call then we use the cached value.
2060 jlong referrer_tag;
2061 if (referrer == context->last_referrer()) {
2062 referrer_tag = context->last_referrer_tag();
2063 } else {
2064 referrer_tag = tag_for(tag_map(), referrer);
2065 }
2066
2067 // do the callback
2068 CallbackWrapper wrapper(tag_map(), referree);
2069 jvmtiObjectReferenceCallback cb = context->object_ref_callback();
2070 jvmtiIterationControl control = (*cb)(ref_kind,
2071 wrapper.klass_tag(),
2072 wrapper.obj_size(),
2073 wrapper.obj_tag_p(),
2074 referrer_tag,
2075 index,
2076 (void*)user_data());
2077
2078 // record referrer and referrer tag. For self-references record the
2079 // tag value from the callback as this might differ from referrer_tag.
2080 context->set_last_referrer(referrer);
2081 if (referrer == referree) {
2082 context->set_last_referrer_tag(*wrapper.obj_tag_p());
2083 } else {
2084 context->set_last_referrer_tag(referrer_tag);
2085 }
2086
2087 if (control == JVMTI_ITERATION_CONTINUE) {
2088 return check_for_visit(referree);
2089 } else {
2090 return control != JVMTI_ITERATION_ABORT;
2091 }
2092 }
2093
2094 // invoke advanced style heap root callback
2095 inline bool CallbackInvoker::invoke_advanced_heap_root_callback(jvmtiHeapReferenceKind ref_kind,
2096 oop obj) {
2097 assert(ServiceUtil::visible_oop(obj), "checking");
2098
2099 AdvancedHeapWalkContext* context = advanced_context();
2100
2101 // check that callback is provided
2102 jvmtiHeapReferenceCallback cb = context->heap_reference_callback();
2103 if (cb == NULL) {
2104 return check_for_visit(obj);
2105 }
2106
2107 // apply class filter
2108 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
2109 return check_for_visit(obj);
2110 }
2111
2112 // setup the callback wrapper
2113 CallbackWrapper wrapper(tag_map(), obj);
2114
2115 // apply tag filter
2116 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2117 wrapper.klass_tag(),
2118 context->heap_filter())) {
2119 return check_for_visit(obj);
2120 }
2121
2122 // for arrays we need the length, otherwise -1
2123 jint len = (jint)(obj->is_array() ? arrayOop(obj)->length() : -1);
2124
2125 // invoke the callback
2126 jint res = (*cb)(ref_kind,
2127 NULL, // referrer info
2128 wrapper.klass_tag(),
2129 0, // referrer_class_tag is 0 for heap root
2130 wrapper.obj_size(),
2131 wrapper.obj_tag_p(),
2132 NULL, // referrer_tag_p
2133 len,
2134 (void*)user_data());
2135 if (res & JVMTI_VISIT_ABORT) {
2136 return false;// referrer class tag
2137 }
2138 if (res & JVMTI_VISIT_OBJECTS) {
2139 check_for_visit(obj);
2140 }
2141 return true;
2142 }
2143
2144 // report a reference from a thread stack to an object
2145 inline bool CallbackInvoker::invoke_advanced_stack_ref_callback(jvmtiHeapReferenceKind ref_kind,
2146 jlong thread_tag,
2147 jlong tid,
2148 int depth,
2149 jmethodID method,
2150 jlocation bci,
2151 jint slot,
2152 oop obj) {
2153 assert(ServiceUtil::visible_oop(obj), "checking");
2154
2155 AdvancedHeapWalkContext* context = advanced_context();
2156
2157 // check that callback is provider
2158 jvmtiHeapReferenceCallback cb = context->heap_reference_callback();
2159 if (cb == NULL) {
2160 return check_for_visit(obj);
2161 }
2162
2163 // apply class filter
2164 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
2165 return check_for_visit(obj);
2166 }
2167
2168 // setup the callback wrapper
2169 CallbackWrapper wrapper(tag_map(), obj);
2170
2171 // apply tag filter
2172 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2173 wrapper.klass_tag(),
2174 context->heap_filter())) {
2175 return check_for_visit(obj);
2176 }
2177
2178 // setup the referrer info
2179 jvmtiHeapReferenceInfo reference_info;
2180 reference_info.stack_local.thread_tag = thread_tag;
2181 reference_info.stack_local.thread_id = tid;
2182 reference_info.stack_local.depth = depth;
2183 reference_info.stack_local.method = method;
2184 reference_info.stack_local.location = bci;
2185 reference_info.stack_local.slot = slot;
2186
2187 // for arrays we need the length, otherwise -1
2188 jint len = (jint)(obj->is_array() ? arrayOop(obj)->length() : -1);
2189
2190 // call into the agent
2191 int res = (*cb)(ref_kind,
2192 &reference_info,
2193 wrapper.klass_tag(),
2194 0, // referrer_class_tag is 0 for heap root (stack)
2195 wrapper.obj_size(),
2196 wrapper.obj_tag_p(),
2197 NULL, // referrer_tag is 0 for root
2198 len,
2199 (void*)user_data());
2200
2201 if (res & JVMTI_VISIT_ABORT) {
2202 return false;
2203 }
2204 if (res & JVMTI_VISIT_OBJECTS) {
2205 check_for_visit(obj);
2206 }
2207 return true;
2208 }
2209
2210 // This mask is used to pass reference_info to a jvmtiHeapReferenceCallback
2211 // only for ref_kinds defined by the JVM TI spec. Otherwise, NULL is passed.
2212 #define REF_INFO_MASK ((1 << JVMTI_HEAP_REFERENCE_FIELD) \
2213 | (1 << JVMTI_HEAP_REFERENCE_STATIC_FIELD) \
2214 | (1 << JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT) \
2215 | (1 << JVMTI_HEAP_REFERENCE_CONSTANT_POOL) \
2216 | (1 << JVMTI_HEAP_REFERENCE_STACK_LOCAL) \
2217 | (1 << JVMTI_HEAP_REFERENCE_JNI_LOCAL))
2218
2219 // invoke the object reference callback to report a reference
2220 inline bool CallbackInvoker::invoke_advanced_object_reference_callback(jvmtiHeapReferenceKind ref_kind,
2221 oop referrer,
2222 oop obj,
2223 jint index)
2224 {
2225 // field index is only valid field in reference_info
2226 static jvmtiHeapReferenceInfo reference_info = { 0 };
2227
2228 assert(ServiceUtil::visible_oop(referrer), "checking");
2229 assert(ServiceUtil::visible_oop(obj), "checking");
2230
2231 AdvancedHeapWalkContext* context = advanced_context();
2232
2233 // check that callback is provider
2234 jvmtiHeapReferenceCallback cb = context->heap_reference_callback();
2235 if (cb == NULL) {
2236 return check_for_visit(obj);
2237 }
2238
2239 // apply class filter
2240 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
2241 return check_for_visit(obj);
2242 }
2243
2244 // setup the callback wrapper
2245 TwoOopCallbackWrapper wrapper(tag_map(), referrer, obj);
2246
2247 // apply tag filter
2248 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2249 wrapper.klass_tag(),
2250 context->heap_filter())) {
2251 return check_for_visit(obj);
2252 }
2253
2254 // field index is only valid field in reference_info
2255 reference_info.field.index = index;
2256
2257 // for arrays we need the length, otherwise -1
2258 jint len = (jint)(obj->is_array() ? arrayOop(obj)->length() : -1);
2259
2260 // invoke the callback
2261 int res = (*cb)(ref_kind,
2262 (REF_INFO_MASK & (1 << ref_kind)) ? &reference_info : NULL,
2263 wrapper.klass_tag(),
2264 wrapper.referrer_klass_tag(),
2265 wrapper.obj_size(),
2266 wrapper.obj_tag_p(),
2267 wrapper.referrer_tag_p(),
2268 len,
2269 (void*)user_data());
2270
2271 if (res & JVMTI_VISIT_ABORT) {
2272 return false;
2273 }
2274 if (res & JVMTI_VISIT_OBJECTS) {
2275 check_for_visit(obj);
2276 }
2277 return true;
2278 }
2279
2280 // report a "simple root"
2281 inline bool CallbackInvoker::report_simple_root(jvmtiHeapReferenceKind kind, oop obj) {
2282 assert(kind != JVMTI_HEAP_REFERENCE_STACK_LOCAL &&
2283 kind != JVMTI_HEAP_REFERENCE_JNI_LOCAL, "not a simple root");
2284 assert(ServiceUtil::visible_oop(obj), "checking");
2285
2286 if (is_basic_heap_walk()) {
2287 // map to old style root kind
2288 jvmtiHeapRootKind root_kind = toJvmtiHeapRootKind(kind);
2289 return invoke_basic_heap_root_callback(root_kind, obj);
2290 } else {
2291 assert(is_advanced_heap_walk(), "wrong heap walk type");
2292 return invoke_advanced_heap_root_callback(kind, obj);
2293 }
2294 }
2295
2296
2297 // invoke the primitive array values
2298 inline bool CallbackInvoker::report_primitive_array_values(oop obj) {
2299 assert(obj->is_typeArray(), "not a primitive array");
2300
2301 AdvancedHeapWalkContext* context = advanced_context();
2302 assert(context->array_primitive_value_callback() != NULL, "no callback");
2303
2304 // apply class filter
2305 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
2306 return true;
2307 }
2308
2309 CallbackWrapper wrapper(tag_map(), obj);
2310
2311 // apply tag filter
2312 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2313 wrapper.klass_tag(),
2314 context->heap_filter())) {
2315 return true;
2316 }
2317
2318 // invoke the callback
2319 int res = invoke_array_primitive_value_callback(context->array_primitive_value_callback(),
2320 &wrapper,
2321 obj,
2322 (void*)user_data());
2323 return (!(res & JVMTI_VISIT_ABORT));
2324 }
2325
2326 // invoke the string value callback
2327 inline bool CallbackInvoker::report_string_value(oop str) {
2328 assert(str->klass() == SystemDictionary::String_klass(), "not a string");
2329
2330 AdvancedHeapWalkContext* context = advanced_context();
2331 assert(context->string_primitive_value_callback() != NULL, "no callback");
2332
2333 // apply class filter
2334 if (is_filtered_by_klass_filter(str, context->klass_filter())) {
2335 return true;
2336 }
2337
2338 CallbackWrapper wrapper(tag_map(), str);
2339
2340 // apply tag filter
2341 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2342 wrapper.klass_tag(),
2343 context->heap_filter())) {
2344 return true;
2345 }
2346
2347 // invoke the callback
2348 int res = invoke_string_value_callback(context->string_primitive_value_callback(),
2349 &wrapper,
2350 str,
2351 (void*)user_data());
2352 return (!(res & JVMTI_VISIT_ABORT));
2353 }
2354
2355 // invoke the primitive field callback
2356 inline bool CallbackInvoker::report_primitive_field(jvmtiHeapReferenceKind ref_kind,
2357 oop obj,
2358 jint index,
2359 address addr,
2360 char type)
2361 {
2362 // for primitive fields only the index will be set
2363 static jvmtiHeapReferenceInfo reference_info = { 0 };
2364
2365 AdvancedHeapWalkContext* context = advanced_context();
2366 assert(context->primitive_field_callback() != NULL, "no callback");
2367
2368 // apply class filter
2369 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
2370 return true;
2371 }
2372
2373 CallbackWrapper wrapper(tag_map(), obj);
2374
2375 // apply tag filter
2376 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2377 wrapper.klass_tag(),
2378 context->heap_filter())) {
2379 return true;
2380 }
2381
2382 // the field index in the referrer
2383 reference_info.field.index = index;
2384
2385 // map the type
2386 jvmtiPrimitiveType value_type = (jvmtiPrimitiveType)type;
2387
2388 // setup the jvalue
2389 jvalue value;
2390 copy_to_jvalue(&value, addr, value_type);
2391
2392 jvmtiPrimitiveFieldCallback cb = context->primitive_field_callback();
2393 int res = (*cb)(ref_kind,
2394 &reference_info,
2395 wrapper.klass_tag(),
2396 wrapper.obj_tag_p(),
2397 value,
2398 value_type,
2399 (void*)user_data());
2400 return (!(res & JVMTI_VISIT_ABORT));
2401 }
2402
2403
2404 // instance field
2405 inline bool CallbackInvoker::report_primitive_instance_field(oop obj,
2406 jint index,
2407 address value,
2408 char type) {
2409 return report_primitive_field(JVMTI_HEAP_REFERENCE_FIELD,
2410 obj,
2411 index,
2412 value,
2413 type);
2414 }
2415
2416 // static field
2417 inline bool CallbackInvoker::report_primitive_static_field(oop obj,
2418 jint index,
2419 address value,
2420 char type) {
2421 return report_primitive_field(JVMTI_HEAP_REFERENCE_STATIC_FIELD,
2422 obj,
2423 index,
2424 value,
2425 type);
2426 }
2427
2428 // report a JNI local (root object) to the profiler
2429 inline bool CallbackInvoker::report_jni_local_root(jlong thread_tag, jlong tid, jint depth, jmethodID m, oop obj) {
2430 if (is_basic_heap_walk()) {
2431 return invoke_basic_stack_ref_callback(JVMTI_HEAP_ROOT_JNI_LOCAL,
2432 thread_tag,
2433 depth,
2434 m,
2435 -1,
2436 obj);
2437 } else {
2438 return invoke_advanced_stack_ref_callback(JVMTI_HEAP_REFERENCE_JNI_LOCAL,
2439 thread_tag, tid,
2440 depth,
2441 m,
2442 (jlocation)-1,
2443 -1,
2444 obj);
2445 }
2446 }
2447
2448
2449 // report a local (stack reference, root object)
2450 inline bool CallbackInvoker::report_stack_ref_root(jlong thread_tag,
2451 jlong tid,
2452 jint depth,
2453 jmethodID method,
2454 jlocation bci,
2455 jint slot,
2456 oop obj) {
2457 if (is_basic_heap_walk()) {
2458 return invoke_basic_stack_ref_callback(JVMTI_HEAP_ROOT_STACK_LOCAL,
2459 thread_tag,
2460 depth,
2461 method,
2462 slot,
2463 obj);
2464 } else {
2465 return invoke_advanced_stack_ref_callback(JVMTI_HEAP_REFERENCE_STACK_LOCAL,
2466 thread_tag,
2467 tid,
2468 depth,
2469 method,
2470 bci,
2471 slot,
2472 obj);
2473 }
2474 }
2475
2476 // report an object referencing a class.
2477 inline bool CallbackInvoker::report_class_reference(oop referrer, oop referree) {
2478 if (is_basic_heap_walk()) {
2479 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CLASS, referrer, referree, -1);
2480 } else {
2481 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_CLASS, referrer, referree, -1);
2482 }
2483 }
2484
2485 // report a class referencing its class loader.
2486 inline bool CallbackInvoker::report_class_loader_reference(oop referrer, oop referree) {
2487 if (is_basic_heap_walk()) {
2488 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CLASS_LOADER, referrer, referree, -1);
2489 } else {
2490 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_CLASS_LOADER, referrer, referree, -1);
2491 }
2492 }
2493
2494 // report a class referencing its signers.
2495 inline bool CallbackInvoker::report_signers_reference(oop referrer, oop referree) {
2496 if (is_basic_heap_walk()) {
2497 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_SIGNERS, referrer, referree, -1);
2498 } else {
2499 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_SIGNERS, referrer, referree, -1);
2500 }
2501 }
2502
2503 // report a class referencing its protection domain..
2504 inline bool CallbackInvoker::report_protection_domain_reference(oop referrer, oop referree) {
2505 if (is_basic_heap_walk()) {
2506 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_PROTECTION_DOMAIN, referrer, referree, -1);
2507 } else {
2508 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_PROTECTION_DOMAIN, referrer, referree, -1);
2509 }
2510 }
2511
2512 // report a class referencing its superclass.
2513 inline bool CallbackInvoker::report_superclass_reference(oop referrer, oop referree) {
2514 if (is_basic_heap_walk()) {
2515 // Send this to be consistent with past implementation
2516 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CLASS, referrer, referree, -1);
2517 } else {
2518 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_SUPERCLASS, referrer, referree, -1);
2519 }
2520 }
2521
2522 // report a class referencing one of its interfaces.
2523 inline bool CallbackInvoker::report_interface_reference(oop referrer, oop referree) {
2524 if (is_basic_heap_walk()) {
2525 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_INTERFACE, referrer, referree, -1);
2526 } else {
2527 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_INTERFACE, referrer, referree, -1);
2528 }
2529 }
2530
2531 // report a class referencing one of its static fields.
2532 inline bool CallbackInvoker::report_static_field_reference(oop referrer, oop referree, jint slot) {
2533 if (is_basic_heap_walk()) {
2534 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_STATIC_FIELD, referrer, referree, slot);
2535 } else {
2536 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_STATIC_FIELD, referrer, referree, slot);
2537 }
2538 }
2539
2540 // report an array referencing an element object
2541 inline bool CallbackInvoker::report_array_element_reference(oop referrer, oop referree, jint index) {
2542 if (is_basic_heap_walk()) {
2543 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_ARRAY_ELEMENT, referrer, referree, index);
2544 } else {
2545 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT, referrer, referree, index);
2546 }
2547 }
2548
2549 // report an object referencing an instance field object
2550 inline bool CallbackInvoker::report_field_reference(oop referrer, oop referree, jint slot) {
2551 if (is_basic_heap_walk()) {
2552 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_FIELD, referrer, referree, slot);
2553 } else {
2554 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_FIELD, referrer, referree, slot);
2555 }
2556 }
2557
2558 // report an array referencing an element object
2559 inline bool CallbackInvoker::report_constant_pool_reference(oop referrer, oop referree, jint index) {
2560 if (is_basic_heap_walk()) {
2561 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CONSTANT_POOL, referrer, referree, index);
2562 } else {
2563 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_CONSTANT_POOL, referrer, referree, index);
2564 }
2565 }
2566
2567 // A supporting closure used to process simple roots
2568 class SimpleRootsClosure : public OopClosure {
2569 private:
2570 jvmtiHeapReferenceKind _kind;
2571 bool _continue;
2572
2573 jvmtiHeapReferenceKind root_kind() { return _kind; }
2574
2575 public:
2576 void set_kind(jvmtiHeapReferenceKind kind) {
2577 _kind = kind;
2578 _continue = true;
2579 }
2580
2581 inline bool stopped() {
2582 return !_continue;
2583 }
2584
2585 void do_oop(oop* obj_p) {
2586 // iteration has terminated
2587 if (stopped()) {
2588 return;
2589 }
2590
2591 oop o = *obj_p;
2592 // ignore null
2593 if (o == NULL) {
2594 return;
2595 }
2596
2597 assert(Universe::heap()->is_in_reserved(o), "should be impossible");
2598
2599 jvmtiHeapReferenceKind kind = root_kind();
2600 if (kind == JVMTI_HEAP_REFERENCE_SYSTEM_CLASS) {
2601 // SystemDictionary::always_strong_oops_do reports the application
2602 // class loader as a root. We want this root to be reported as
2603 // a root kind of "OTHER" rather than "SYSTEM_CLASS".
2604 if (!o->is_instance() || !InstanceKlass::cast(o->klass())->is_mirror_instance_klass()) {
2605 kind = JVMTI_HEAP_REFERENCE_OTHER;
2606 }
2607 }
2608
2609 // some objects are ignored - in the case of simple
2610 // roots it's mostly Symbol*s that we are skipping
2611 // here.
2612 if (!ServiceUtil::visible_oop(o)) {
2613 return;
2614 }
2615
2616 // invoke the callback
2617 _continue = CallbackInvoker::report_simple_root(kind, o);
2618
2619 }
2620 virtual void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }
2621 };
2622
2623 // A supporting closure used to process JNI locals
2624 class JNILocalRootsClosure : public OopClosure {
2625 private:
2626 jlong _thread_tag;
2627 jlong _tid;
2628 jint _depth;
2629 jmethodID _method;
2630 bool _continue;
2631 public:
2632 void set_context(jlong thread_tag, jlong tid, jint depth, jmethodID method) {
2633 _thread_tag = thread_tag;
2634 _tid = tid;
2635 _depth = depth;
2636 _method = method;
2637 _continue = true;
2638 }
2639
2640 inline bool stopped() {
2641 return !_continue;
2642 }
2643
2644 void do_oop(oop* obj_p) {
2645 // iteration has terminated
2646 if (stopped()) {
2647 return;
2648 }
2649
2650 oop o = *obj_p;
2651 // ignore null
2652 if (o == NULL) {
2653 return;
2654 }
2655
2656 if (!ServiceUtil::visible_oop(o)) {
2657 return;
2658 }
2659
2660 // invoke the callback
2661 _continue = CallbackInvoker::report_jni_local_root(_thread_tag, _tid, _depth, _method, o);
2662 }
2663 virtual void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }
2664 };
2665
2666
2667 // A VM operation to iterate over objects that are reachable from
2668 // a set of roots or an initial object.
2669 //
2670 // For VM_HeapWalkOperation the set of roots used is :-
2671 //
2672 // - All JNI global references
2673 // - All inflated monitors
2674 // - All classes loaded by the boot class loader (or all classes
2675 // in the event that class unloading is disabled)
2676 // - All java threads
2677 // - For each java thread then all locals and JNI local references
2678 // on the thread's execution stack
2679 // - All visible/explainable objects from Universes::oops_do
2680 //
2681 class VM_HeapWalkOperation: public VM_Operation {
2682 private:
2683 enum {
2684 initial_visit_stack_size = 4000
2685 };
2686
2687 bool _is_advanced_heap_walk; // indicates FollowReferences
2688 JvmtiTagMap* _tag_map;
2689 Handle _initial_object;
2690 GrowableArray<oop>* _visit_stack; // the visit stack
2691
2692 bool _collecting_heap_roots; // are we collecting roots
2693 bool _following_object_refs; // are we following object references
2694
2695 bool _reporting_primitive_fields; // optional reporting
2696 bool _reporting_primitive_array_values;
2697 bool _reporting_string_values;
2698
2699 GrowableArray<oop>* create_visit_stack() {
2700 return new (ResourceObj::C_HEAP, mtInternal) GrowableArray<oop>(initial_visit_stack_size, true);
2701 }
2702
2703 // accessors
2704 bool is_advanced_heap_walk() const { return _is_advanced_heap_walk; }
2705 JvmtiTagMap* tag_map() const { return _tag_map; }
2706 Handle initial_object() const { return _initial_object; }
2707
2708 bool is_following_references() const { return _following_object_refs; }
2709
2710 bool is_reporting_primitive_fields() const { return _reporting_primitive_fields; }
2711 bool is_reporting_primitive_array_values() const { return _reporting_primitive_array_values; }
2712 bool is_reporting_string_values() const { return _reporting_string_values; }
2713
2714 GrowableArray<oop>* visit_stack() const { return _visit_stack; }
2715
2716 // iterate over the various object types
2717 inline bool iterate_over_array(oop o);
2718 inline bool iterate_over_type_array(oop o);
2719 inline bool iterate_over_class(oop o);
2720 inline bool iterate_over_object(oop o);
2721
2722 // root collection
2723 inline bool collect_simple_roots();
2724 inline bool collect_stack_roots();
2725 inline bool collect_stack_roots(JavaThread* java_thread, JNILocalRootsClosure* blk);
2726
2727 // visit an object
2728 inline bool visit(oop o);
2729
2730 public:
2731 VM_HeapWalkOperation(JvmtiTagMap* tag_map,
2732 Handle initial_object,
2733 BasicHeapWalkContext callbacks,
2734 const void* user_data);
2735
2736 VM_HeapWalkOperation(JvmtiTagMap* tag_map,
2737 Handle initial_object,
2738 AdvancedHeapWalkContext callbacks,
2739 const void* user_data);
2740
2741 ~VM_HeapWalkOperation();
2742
2743 VMOp_Type type() const { return VMOp_HeapWalkOperation; }
2744 void doit();
2745 };
2746
2747
2748 VM_HeapWalkOperation::VM_HeapWalkOperation(JvmtiTagMap* tag_map,
2749 Handle initial_object,
2750 BasicHeapWalkContext callbacks,
2751 const void* user_data) {
2752 _is_advanced_heap_walk = false;
2753 _tag_map = tag_map;
2754 _initial_object = initial_object;
2755 _following_object_refs = (callbacks.object_ref_callback() != NULL);
2756 _reporting_primitive_fields = false;
2757 _reporting_primitive_array_values = false;
2758 _reporting_string_values = false;
2759 _visit_stack = create_visit_stack();
2760
2761
2762 CallbackInvoker::initialize_for_basic_heap_walk(tag_map, _visit_stack, user_data, callbacks);
2763 }
2764
2765 VM_HeapWalkOperation::VM_HeapWalkOperation(JvmtiTagMap* tag_map,
2766 Handle initial_object,
2767 AdvancedHeapWalkContext callbacks,
2768 const void* user_data) {
2769 _is_advanced_heap_walk = true;
2770 _tag_map = tag_map;
2771 _initial_object = initial_object;
2772 _following_object_refs = true;
2773 _reporting_primitive_fields = (callbacks.primitive_field_callback() != NULL);;
2774 _reporting_primitive_array_values = (callbacks.array_primitive_value_callback() != NULL);;
2775 _reporting_string_values = (callbacks.string_primitive_value_callback() != NULL);;
2776 _visit_stack = create_visit_stack();
2777
2778 CallbackInvoker::initialize_for_advanced_heap_walk(tag_map, _visit_stack, user_data, callbacks);
2779 }
2780
2781 VM_HeapWalkOperation::~VM_HeapWalkOperation() {
2782 if (_following_object_refs) {
2783 assert(_visit_stack != NULL, "checking");
2784 delete _visit_stack;
2785 _visit_stack = NULL;
2786 }
2787 }
2788
2789 // an array references its class and has a reference to
2790 // each element in the array
2791 inline bool VM_HeapWalkOperation::iterate_over_array(oop o) {
2792 objArrayOop array = objArrayOop(o);
2793
2794 // array reference to its class
2795 oop mirror = ObjArrayKlass::cast(array->klass())->java_mirror();
2796 if (!CallbackInvoker::report_class_reference(o, mirror)) {
2797 return false;
2798 }
2799
2800 // iterate over the array and report each reference to a
2801 // non-null element
2802 for (int index=0; index<array->length(); index++) {
2803 oop elem = array->obj_at(index);
2804 if (elem == NULL) {
2805 continue;
2806 }
2807
2808 // report the array reference o[index] = elem
2809 if (!CallbackInvoker::report_array_element_reference(o, elem, index)) {
2810 return false;
2811 }
2812 }
2813 return true;
2814 }
2815
2816 // a type array references its class
2817 inline bool VM_HeapWalkOperation::iterate_over_type_array(oop o) {
2818 Klass* k = o->klass();
2819 oop mirror = k->java_mirror();
2820 if (!CallbackInvoker::report_class_reference(o, mirror)) {
2821 return false;
2822 }
2823
2824 // report the array contents if required
2825 if (is_reporting_primitive_array_values()) {
2826 if (!CallbackInvoker::report_primitive_array_values(o)) {
2827 return false;
2828 }
2829 }
2830 return true;
2831 }
2832
2833 #ifdef ASSERT
2834 // verify that a static oop field is in range
2835 static inline bool verify_static_oop(InstanceKlass* ik,
2836 oop mirror, int offset) {
2837 address obj_p = (address)mirror + offset;
2838 address start = (address)InstanceMirrorKlass::start_of_static_fields(mirror);
2839 address end = start + (java_lang_Class::static_oop_field_count(mirror) * heapOopSize);
2840 assert(end >= start, "sanity check");
2841
2842 if (obj_p >= start && obj_p < end) {
2843 return true;
2844 } else {
2845 return false;
2846 }
2847 }
2848 #endif // #ifdef ASSERT
2849
2850 // a class references its super class, interfaces, class loader, ...
2851 // and finally its static fields
2852 inline bool VM_HeapWalkOperation::iterate_over_class(oop java_class) {
2853 int i;
2854 Klass* klass = java_lang_Class::as_Klass(java_class);
2855
2856 if (klass->is_instance_klass()) {
2857 InstanceKlass* ik = InstanceKlass::cast(klass);
2858
2859 // Ignore the class if it hasn't been initialized yet
2860 if (!ik->is_linked()) {
2861 return true;
2862 }
2863
2864 // get the java mirror
2865 oop mirror = klass->java_mirror();
2866
2867 // super (only if something more interesting than java.lang.Object)
2868 Klass* java_super = ik->java_super();
2869 if (java_super != NULL && java_super != SystemDictionary::Object_klass()) {
2870 oop super = java_super->java_mirror();
2871 if (!CallbackInvoker::report_superclass_reference(mirror, super)) {
2872 return false;
2873 }
2874 }
2875
2876 // class loader
2877 oop cl = ik->class_loader();
2878 if (cl != NULL) {
2879 if (!CallbackInvoker::report_class_loader_reference(mirror, cl)) {
2880 return false;
2881 }
2882 }
2883
2884 // protection domain
2885 oop pd = ik->protection_domain();
2886 if (pd != NULL) {
2887 if (!CallbackInvoker::report_protection_domain_reference(mirror, pd)) {
2888 return false;
2889 }
2890 }
2891
2892 // signers
2893 oop signers = ik->signers();
2894 if (signers != NULL) {
2895 if (!CallbackInvoker::report_signers_reference(mirror, signers)) {
2896 return false;
2897 }
2898 }
2899
2900 // references from the constant pool
2901 {
2902 ConstantPool* pool = ik->constants();
2903 for (int i = 1; i < pool->length(); i++) {
2904 constantTag tag = pool->tag_at(i).value();
2905 if (tag.is_string() || tag.is_klass()) {
2906 oop entry;
2907 if (tag.is_string()) {
2908 entry = pool->resolved_string_at(i);
2909 // If the entry is non-null it is resolved.
2910 if (entry == NULL) continue;
2911 } else {
2912 entry = pool->resolved_klass_at(i)->java_mirror();
2913 }
2914 if (!CallbackInvoker::report_constant_pool_reference(mirror, entry, (jint)i)) {
2915 return false;
2916 }
2917 }
2918 }
2919 }
2920
2921 // interfaces
2922 // (These will already have been reported as references from the constant pool
2923 // but are specified by IterateOverReachableObjects and must be reported).
2924 Array<Klass*>* interfaces = ik->local_interfaces();
2925 for (i = 0; i < interfaces->length(); i++) {
2926 oop interf = ((Klass*)interfaces->at(i))->java_mirror();
2927 if (interf == NULL) {
2928 continue;
2929 }
2930 if (!CallbackInvoker::report_interface_reference(mirror, interf)) {
2931 return false;
2932 }
2933 }
2934
2935 // iterate over the static fields
2936
2937 ClassFieldMap* field_map = ClassFieldMap::create_map_of_static_fields(klass);
2938 for (i=0; i<field_map->field_count(); i++) {
2939 ClassFieldDescriptor* field = field_map->field_at(i);
2940 char type = field->field_type();
2941 if (!is_primitive_field_type(type)) {
2942 oop fld_o = mirror->obj_field(field->field_offset());
2943 assert(verify_static_oop(ik, mirror, field->field_offset()), "sanity check");
2944 if (fld_o != NULL) {
2945 int slot = field->field_index();
2946 if (!CallbackInvoker::report_static_field_reference(mirror, fld_o, slot)) {
2947 delete field_map;
2948 return false;
2949 }
2950 }
2951 } else {
2952 if (is_reporting_primitive_fields()) {
2953 address addr = (address)mirror + field->field_offset();
2954 int slot = field->field_index();
2955 if (!CallbackInvoker::report_primitive_static_field(mirror, slot, addr, type)) {
2956 delete field_map;
2957 return false;
2958 }
2959 }
2960 }
2961 }
2962 delete field_map;
2963
2964 return true;
2965 }
2966
2967 return true;
2968 }
2969
2970 // an object references a class and its instance fields
2971 // (static fields are ignored here as we report these as
2972 // references from the class).
2973 inline bool VM_HeapWalkOperation::iterate_over_object(oop o) {
2974 // reference to the class
2975 if (!CallbackInvoker::report_class_reference(o, o->klass()->java_mirror())) {
2976 return false;
2977 }
2978
2979 // iterate over instance fields
2980 ClassFieldMap* field_map = JvmtiCachedClassFieldMap::get_map_of_instance_fields(o);
2981 for (int i=0; i<field_map->field_count(); i++) {
2982 ClassFieldDescriptor* field = field_map->field_at(i);
2983 char type = field->field_type();
2984 if (!is_primitive_field_type(type)) {
2985 oop fld_o = o->obj_field(field->field_offset());
2986 // ignore any objects that aren't visible to profiler
2987 if (fld_o != NULL && ServiceUtil::visible_oop(fld_o)) {
2988 assert(Universe::heap()->is_in_reserved(fld_o), "unsafe code should not "
2989 "have references to Klass* anymore");
2990 int slot = field->field_index();
2991 if (!CallbackInvoker::report_field_reference(o, fld_o, slot)) {
2992 return false;
2993 }
2994 }
2995 } else {
2996 if (is_reporting_primitive_fields()) {
2997 // primitive instance field
2998 address addr = (address)o + field->field_offset();
2999 int slot = field->field_index();
3000 if (!CallbackInvoker::report_primitive_instance_field(o, slot, addr, type)) {
3001 return false;
3002 }
3003 }
3004 }
3005 }
3006
3007 // if the object is a java.lang.String
3008 if (is_reporting_string_values() &&
3009 o->klass() == SystemDictionary::String_klass()) {
3010 if (!CallbackInvoker::report_string_value(o)) {
3011 return false;
3012 }
3013 }
3014 return true;
3015 }
3016
3017
3018 // Collects all simple (non-stack) roots except for threads;
3019 // threads are handled in collect_stack_roots() as an optimization.
3020 // if there's a heap root callback provided then the callback is
3021 // invoked for each simple root.
3022 // if an object reference callback is provided then all simple
3023 // roots are pushed onto the marking stack so that they can be
3024 // processed later
3025 //
3026 inline bool VM_HeapWalkOperation::collect_simple_roots() {
3027 SimpleRootsClosure blk;
3028
3029 // JNI globals
3030 blk.set_kind(JVMTI_HEAP_REFERENCE_JNI_GLOBAL);
3031 JNIHandles::oops_do(&blk);
3032 if (blk.stopped()) {
3033 return false;
3034 }
3035
3036 // Preloaded classes and loader from the system dictionary
3037 blk.set_kind(JVMTI_HEAP_REFERENCE_SYSTEM_CLASS);
3038 SystemDictionary::always_strong_oops_do(&blk);
3039 ClassLoaderDataGraph::always_strong_oops_do(&blk, false);
3040 if (blk.stopped()) {
3041 return false;
3042 }
3043
3044 // Inflated monitors
3045 blk.set_kind(JVMTI_HEAP_REFERENCE_MONITOR);
3046 ObjectSynchronizer::oops_do(&blk);
3047 if (blk.stopped()) {
3048 return false;
3049 }
3050
3051 // threads are now handled in collect_stack_roots()
3052
3053 // Other kinds of roots maintained by HotSpot
3054 // Many of these won't be visible but others (such as instances of important
3055 // exceptions) will be visible.
3056 blk.set_kind(JVMTI_HEAP_REFERENCE_OTHER);
3057 Universe::oops_do(&blk);
3058
3059 // If there are any non-perm roots in the code cache, visit them.
3060 blk.set_kind(JVMTI_HEAP_REFERENCE_OTHER);
3061 CodeBlobToOopClosure look_in_blobs(&blk, !CodeBlobToOopClosure::FixRelocations);
3062 CodeCache::scavenge_root_nmethods_do(&look_in_blobs);
3063
3064 return true;
3065 }
3066
3067 // Walk the stack of a given thread and find all references (locals
3068 // and JNI calls) and report these as stack references
3069 inline bool VM_HeapWalkOperation::collect_stack_roots(JavaThread* java_thread,
3070 JNILocalRootsClosure* blk)
3071 {
3072 oop threadObj = java_thread->threadObj();
3073 assert(threadObj != NULL, "sanity check");
3074
3075 // only need to get the thread's tag once per thread
3076 jlong thread_tag = tag_for(_tag_map, threadObj);
3077
3078 // also need the thread id
3079 jlong tid = java_lang_Thread::thread_id(threadObj);
3080
3081
3082 if (java_thread->has_last_Java_frame()) {
3083
3084 // vframes are resource allocated
3085 Thread* current_thread = Thread::current();
3086 ResourceMark rm(current_thread);
3087 HandleMark hm(current_thread);
3088
3089 RegisterMap reg_map(java_thread);
3090 frame f = java_thread->last_frame();
3091 vframe* vf = vframe::new_vframe(&f, ®_map, java_thread);
3092
3093 bool is_top_frame = true;
3094 int depth = 0;
3095 frame* last_entry_frame = NULL;
3096
3097 while (vf != NULL) {
3098 if (vf->is_java_frame()) {
3099
3100 // java frame (interpreted, compiled, ...)
3101 javaVFrame *jvf = javaVFrame::cast(vf);
3102
3103 // the jmethodID
3104 jmethodID method = jvf->method()->jmethod_id();
3105
3106 if (!(jvf->method()->is_native())) {
3107 jlocation bci = (jlocation)jvf->bci();
3108 StackValueCollection* locals = jvf->locals();
3109 for (int slot=0; slot<locals->size(); slot++) {
3110 if (locals->at(slot)->type() == T_OBJECT) {
3111 oop o = locals->obj_at(slot)();
3112 if (o == NULL) {
3113 continue;
3114 }
3115
3116 // stack reference
3117 if (!CallbackInvoker::report_stack_ref_root(thread_tag, tid, depth, method,
3118 bci, slot, o)) {
3119 return false;
3120 }
3121 }
3122 }
3123
3124 StackValueCollection* exprs = jvf->expressions();
3125 for (int index=0; index < exprs->size(); index++) {
3126 if (exprs->at(index)->type() == T_OBJECT) {
3127 oop o = exprs->obj_at(index)();
3128 if (o == NULL) {
3129 continue;
3130 }
3131
3132 // stack reference
3133 if (!CallbackInvoker::report_stack_ref_root(thread_tag, tid, depth, method,
3134 bci, locals->size() + index, o)) {
3135 return false;
3136 }
3137 }
3138 }
3139
3140 // Follow oops from compiled nmethod
3141 if (jvf->cb() != NULL && jvf->cb()->is_nmethod()) {
3142 blk->set_context(thread_tag, tid, depth, method);
3143 jvf->cb()->as_nmethod()->oops_do(blk);
3144 }
3145 } else {
3146 blk->set_context(thread_tag, tid, depth, method);
3147 if (is_top_frame) {
3148 // JNI locals for the top frame.
3149 java_thread->active_handles()->oops_do(blk);
3150 } else {
3151 if (last_entry_frame != NULL) {
3152 // JNI locals for the entry frame
3153 assert(last_entry_frame->is_entry_frame(), "checking");
3154 last_entry_frame->entry_frame_call_wrapper()->handles()->oops_do(blk);
3155 }
3156 }
3157 }
3158 last_entry_frame = NULL;
3159 depth++;
3160 } else {
3161 // externalVFrame - for an entry frame then we report the JNI locals
3162 // when we find the corresponding javaVFrame
3163 frame* fr = vf->frame_pointer();
3164 assert(fr != NULL, "sanity check");
3165 if (fr->is_entry_frame()) {
3166 last_entry_frame = fr;
3167 }
3168 }
3169
3170 vf = vf->sender();
3171 is_top_frame = false;
3172 }
3173 } else {
3174 // no last java frame but there may be JNI locals
3175 blk->set_context(thread_tag, tid, 0, (jmethodID)NULL);
3176 java_thread->active_handles()->oops_do(blk);
3177 }
3178 return true;
3179 }
3180
3181
3182 // Collects the simple roots for all threads and collects all
3183 // stack roots - for each thread it walks the execution
3184 // stack to find all references and local JNI refs.
3185 inline bool VM_HeapWalkOperation::collect_stack_roots() {
3186 JNILocalRootsClosure blk;
3187 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thread = jtiwh.next(); ) {
3188 oop threadObj = thread->threadObj();
3189 if (threadObj != NULL && !thread->is_exiting() && !thread->is_hidden_from_external_view()) {
3190 // Collect the simple root for this thread before we
3191 // collect its stack roots
3192 if (!CallbackInvoker::report_simple_root(JVMTI_HEAP_REFERENCE_THREAD,
3193 threadObj)) {
3194 return false;
3195 }
3196 if (!collect_stack_roots(thread, &blk)) {
3197 return false;
3198 }
3199 }
3200 }
3201 return true;
3202 }
3203
3204 // visit an object
3205 // first mark the object as visited
3206 // second get all the outbound references from this object (in other words, all
3207 // the objects referenced by this object).
3208 //
3209 bool VM_HeapWalkOperation::visit(oop o) {
3210 // mark object as visited
3211 assert(!ObjectMarker::visited(o), "can't visit same object more than once");
3212 ObjectMarker::mark(o);
3213
3214 // instance
3215 if (o->is_instance()) {
3216 if (o->klass() == SystemDictionary::Class_klass()) {
3217 if (!java_lang_Class::is_primitive(o)) {
3218 // a java.lang.Class
3219 return iterate_over_class(o);
3220 }
3221 } else {
3222 return iterate_over_object(o);
3223 }
3224 }
3225
3226 // object array
3227 if (o->is_objArray()) {
3228 return iterate_over_array(o);
3229 }
3230
3231 // type array
3232 if (o->is_typeArray()) {
3233 return iterate_over_type_array(o);
3234 }
3235
3236 return true;
3237 }
3238
3239 void VM_HeapWalkOperation::doit() {
3240 ResourceMark rm;
3241 ObjectMarkerController marker;
3242 ClassFieldMapCacheMark cm;
3243
3244 assert(visit_stack()->is_empty(), "visit stack must be empty");
3245
3246 // the heap walk starts with an initial object or the heap roots
3247 if (initial_object().is_null()) {
3248 // If either collect_stack_roots() or collect_simple_roots()
3249 // returns false at this point, then there are no mark bits
3250 // to reset.
3251 ObjectMarker::set_needs_reset(false);
3252
3253 // Calling collect_stack_roots() before collect_simple_roots()
3254 // can result in a big performance boost for an agent that is
3255 // focused on analyzing references in the thread stacks.
3256 if (!collect_stack_roots()) return;
3257
3258 if (!collect_simple_roots()) return;
3259
3260 // no early return so enable heap traversal to reset the mark bits
3261 ObjectMarker::set_needs_reset(true);
3262 } else {
3263 visit_stack()->push(initial_object()());
3264 }
3265
3266 // object references required
3267 if (is_following_references()) {
3268
3269 // visit each object until all reachable objects have been
3270 // visited or the callback asked to terminate the iteration.
3271 while (!visit_stack()->is_empty()) {
3272 oop o = visit_stack()->pop();
3273 if (!ObjectMarker::visited(o)) {
3274 if (!visit(o)) {
3275 break;
3276 }
3277 }
3278 }
3279 }
3280 }
3281
3282 // iterate over all objects that are reachable from a set of roots
3283 void JvmtiTagMap::iterate_over_reachable_objects(jvmtiHeapRootCallback heap_root_callback,
3284 jvmtiStackReferenceCallback stack_ref_callback,
3285 jvmtiObjectReferenceCallback object_ref_callback,
3286 const void* user_data) {
3287 MutexLocker ml(Heap_lock);
3288 BasicHeapWalkContext context(heap_root_callback, stack_ref_callback, object_ref_callback);
3289 VM_HeapWalkOperation op(this, Handle(), context, user_data);
3290 VMThread::execute(&op);
3291 }
3292
3293 // iterate over all objects that are reachable from a given object
3294 void JvmtiTagMap::iterate_over_objects_reachable_from_object(jobject object,
3295 jvmtiObjectReferenceCallback object_ref_callback,
3296 const void* user_data) {
3297 oop obj = JNIHandles::resolve(object);
3298 Handle initial_object(Thread::current(), obj);
3299
3300 MutexLocker ml(Heap_lock);
3301 BasicHeapWalkContext context(NULL, NULL, object_ref_callback);
3302 VM_HeapWalkOperation op(this, initial_object, context, user_data);
3303 VMThread::execute(&op);
3304 }
3305
3306 // follow references from an initial object or the GC roots
3307 void JvmtiTagMap::follow_references(jint heap_filter,
3308 Klass* klass,
3309 jobject object,
3310 const jvmtiHeapCallbacks* callbacks,
3311 const void* user_data)
3312 {
3313 oop obj = JNIHandles::resolve(object);
3314 Handle initial_object(Thread::current(), obj);
3315
3316 MutexLocker ml(Heap_lock);
3317 AdvancedHeapWalkContext context(heap_filter, klass, callbacks);
3318 VM_HeapWalkOperation op(this, initial_object, context, user_data);
3319 VMThread::execute(&op);
3320 }
3321
3322
3323 void JvmtiTagMap::weak_oops_do(BoolObjectClosure* is_alive, OopClosure* f) {
3324 // No locks during VM bring-up (0 threads) and no safepoints after main
3325 // thread creation and before VMThread creation (1 thread); initial GC
3326 // verification can happen in that window which gets to here.
3327 assert(Threads::number_of_threads() <= 1 ||
3328 SafepointSynchronize::is_at_safepoint(),
3329 "must be executed at a safepoint");
3330 if (JvmtiEnv::environments_might_exist()) {
3331 JvmtiEnvIterator it;
3332 for (JvmtiEnvBase* env = it.first(); env != NULL; env = it.next(env)) {
3333 JvmtiTagMap* tag_map = env->tag_map();
3334 if (tag_map != NULL && !tag_map->is_empty()) {
3335 tag_map->do_weak_oops(is_alive, f);
3336 }
3337 }
3338 }
3339 }
3340
3341 void JvmtiTagMap::do_weak_oops(BoolObjectClosure* is_alive, OopClosure* f) {
3342
3343 // does this environment have the OBJECT_FREE event enabled
3344 bool post_object_free = env()->is_enabled(JVMTI_EVENT_OBJECT_FREE);
3345
3346 // counters used for trace message
3347 int freed = 0;
3348 int moved = 0;
3349
3350 JvmtiTagHashmap* hashmap = this->hashmap();
3351
3352 // reenable sizing (if disabled)
3353 hashmap->set_resizing_enabled(true);
3354
3355 // if the hashmap is empty then we can skip it
3356 if (hashmap->_entry_count == 0) {
3357 return;
3358 }
3359
3360 // now iterate through each entry in the table
3361
3362 JvmtiTagHashmapEntry** table = hashmap->table();
3363 int size = hashmap->size();
3364
3365 JvmtiTagHashmapEntry* delayed_add = NULL;
3366
3367 for (int pos = 0; pos < size; ++pos) {
3368 JvmtiTagHashmapEntry* entry = table[pos];
3369 JvmtiTagHashmapEntry* prev = NULL;
3370
3371 while (entry != NULL) {
3372 JvmtiTagHashmapEntry* next = entry->next();
3373
3374 // has object been GC'ed
3375 if (!is_alive->do_object_b(entry->object_peek())) {
3376 // grab the tag
3377 jlong tag = entry->tag();
3378 guarantee(tag != 0, "checking");
3379
3380 // remove GC'ed entry from hashmap and return the
3381 // entry to the free list
3382 hashmap->remove(prev, pos, entry);
3383 destroy_entry(entry);
3384
3385 // post the event to the profiler
3386 if (post_object_free) {
3387 JvmtiExport::post_object_free(env(), tag);
3388 }
3389
3390 ++freed;
3391 } else {
3392 f->do_oop(entry->object_addr());
3393 oop new_oop = entry->object_peek();
3394
3395 // if the object has moved then re-hash it and move its
3396 // entry to its new location.
3397 unsigned int new_pos = JvmtiTagHashmap::hash(new_oop, size);
3398 if (new_pos != (unsigned int)pos) {
3399 if (prev == NULL) {
3400 table[pos] = next;
3401 } else {
3402 prev->set_next(next);
3403 }
3404 if (new_pos < (unsigned int)pos) {
3405 entry->set_next(table[new_pos]);
3406 table[new_pos] = entry;
3407 } else {
3408 // Delay adding this entry to it's new position as we'd end up
3409 // hitting it again during this iteration.
3410 entry->set_next(delayed_add);
3411 delayed_add = entry;
3412 }
3413 moved++;
3414 } else {
3415 // object didn't move
3416 prev = entry;
3417 }
3418 }
3419
3420 entry = next;
3421 }
3422 }
3423
3424 // Re-add all the entries which were kept aside
3425 while (delayed_add != NULL) {
3426 JvmtiTagHashmapEntry* next = delayed_add->next();
3427 unsigned int pos = JvmtiTagHashmap::hash(delayed_add->object_peek(), size);
3428 delayed_add->set_next(table[pos]);
3429 table[pos] = delayed_add;
3430 delayed_add = next;
3431 }
3432
3433 log_debug(jvmti, objecttagging)("(%d->%d, %d freed, %d total moves)",
3434 hashmap->_entry_count + freed, hashmap->_entry_count, freed, moved);
3435 }