1 /*
2 * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/javaClasses.inline.hpp"
27 #include "classfile/symbolTable.hpp"
28 #include "classfile/systemDictionary.hpp"
29 #include "classfile/vmSymbols.hpp"
30 #include "code/codeCache.hpp"
31 #include "jvmtifiles/jvmtiEnv.hpp"
32 #include "memory/allocation.inline.hpp"
33 #include "memory/resourceArea.hpp"
34 #include "oops/access.inline.hpp"
35 #include "oops/arrayOop.inline.hpp"
36 #include "oops/constantPool.inline.hpp"
37 #include "oops/instanceMirrorKlass.hpp"
38 #include "oops/objArrayKlass.hpp"
39 #include "oops/objArrayOop.inline.hpp"
40 #include "oops/oop.inline.hpp"
41 #include "oops/typeArrayOop.inline.hpp"
42 #include "prims/jvmtiEventController.hpp"
43 #include "prims/jvmtiEventController.inline.hpp"
44 #include "prims/jvmtiExport.hpp"
45 #include "prims/jvmtiImpl.hpp"
46 #include "prims/jvmtiTagMap.hpp"
47 #include "runtime/biasedLocking.hpp"
48 #include "runtime/javaCalls.hpp"
49 #include "runtime/jniHandles.inline.hpp"
50 #include "runtime/mutex.hpp"
51 #include "runtime/mutexLocker.hpp"
52 #include "runtime/reflectionUtils.hpp"
53 #include "runtime/thread.inline.hpp"
54 #include "runtime/threadSMR.hpp"
55 #include "runtime/vframe.hpp"
56 #include "runtime/vmThread.hpp"
57 #include "runtime/vm_operations.hpp"
58 #include "utilities/macros.hpp"
59
60 // JvmtiTagHashmapEntry
61 //
62 // Each entry encapsulates a reference to the tagged object
63 // and the tag value. In addition an entry includes a next pointer which
64 // is used to chain entries together.
65
66 class JvmtiTagHashmapEntry : public CHeapObj<mtInternal> {
67 private:
68 friend class JvmtiTagMap;
69
70 oop _object; // tagged object
71 jlong _tag; // the tag
72 JvmtiTagHashmapEntry* _next; // next on the list
73
74 inline void init(oop object, jlong tag) {
75 _object = object;
76 _tag = tag;
77 _next = NULL;
78 }
79
80 // constructor
81 JvmtiTagHashmapEntry(oop object, jlong tag) { init(object, tag); }
82
83 public:
84
85 // accessor methods
86 inline oop* object_addr() { return &_object; }
87 inline oop object() { return RootAccess<ON_PHANTOM_OOP_REF>::oop_load(object_addr()); }
88 // Peek at the object without keeping it alive. The returned object must be
89 // kept alive using a normal access if it leaks out of a thread transition from VM.
90 inline oop object_peek() {
91 return RootAccess<ON_PHANTOM_OOP_REF | AS_NO_KEEPALIVE>::oop_load(object_addr());
92 }
93 inline jlong tag() const { return _tag; }
94
95 inline void set_tag(jlong tag) {
96 assert(tag != 0, "can't be zero");
97 _tag = tag;
98 }
99
100 inline bool equals(oop object) {
101 return object == object_peek();
102 }
103
104 inline JvmtiTagHashmapEntry* next() const { return _next; }
105 inline void set_next(JvmtiTagHashmapEntry* next) { _next = next; }
106 };
107
108
109 // JvmtiTagHashmap
110 //
111 // A hashmap is essentially a table of pointers to entries. Entries
112 // are hashed to a location, or position in the table, and then
113 // chained from that location. The "key" for hashing is address of
114 // the object, or oop. The "value" is the tag value.
115 //
116 // A hashmap maintains a count of the number entries in the hashmap
117 // and resizes if the number of entries exceeds a given threshold.
118 // The threshold is specified as a percentage of the size - for
119 // example a threshold of 0.75 will trigger the hashmap to resize
120 // if the number of entries is >75% of table size.
121 //
122 // A hashmap provides functions for adding, removing, and finding
123 // entries. It also provides a function to iterate over all entries
124 // in the hashmap.
125
126 class JvmtiTagHashmap : public CHeapObj<mtInternal> {
127 private:
128 friend class JvmtiTagMap;
129
130 enum {
131 small_trace_threshold = 10000, // threshold for tracing
132 medium_trace_threshold = 100000,
133 large_trace_threshold = 1000000,
134 initial_trace_threshold = small_trace_threshold
135 };
136
137 static int _sizes[]; // array of possible hashmap sizes
138 int _size; // actual size of the table
139 int _size_index; // index into size table
140
141 int _entry_count; // number of entries in the hashmap
142
143 float _load_factor; // load factor as a % of the size
144 int _resize_threshold; // computed threshold to trigger resizing.
145 bool _resizing_enabled; // indicates if hashmap can resize
146
147 int _trace_threshold; // threshold for trace messages
148
149 JvmtiTagHashmapEntry** _table; // the table of entries.
150
151 // private accessors
152 int resize_threshold() const { return _resize_threshold; }
153 int trace_threshold() const { return _trace_threshold; }
154
155 // initialize the hashmap
156 void init(int size_index=0, float load_factor=4.0f) {
157 int initial_size = _sizes[size_index];
158 _size_index = size_index;
159 _size = initial_size;
160 _entry_count = 0;
161 _trace_threshold = initial_trace_threshold;
162 _load_factor = load_factor;
163 _resize_threshold = (int)(_load_factor * _size);
164 _resizing_enabled = true;
165 size_t s = initial_size * sizeof(JvmtiTagHashmapEntry*);
166 _table = (JvmtiTagHashmapEntry**)os::malloc(s, mtInternal);
167 if (_table == NULL) {
168 vm_exit_out_of_memory(s, OOM_MALLOC_ERROR,
169 "unable to allocate initial hashtable for jvmti object tags");
170 }
171 for (int i=0; i<initial_size; i++) {
172 _table[i] = NULL;
173 }
174 }
175
176 // hash a given key (oop) with the specified size
177 static unsigned int hash(oop key, int size) {
178 // shift right to get better distribution (as these bits will be zero
179 // with aligned addresses)
180 unsigned int addr = (unsigned int)(cast_from_oop<intptr_t>(key));
181 #ifdef _LP64
182 return (addr >> 3) % size;
183 #else
184 return (addr >> 2) % size;
185 #endif
186 }
187
188 // hash a given key (oop)
189 unsigned int hash(oop key) {
190 return hash(key, _size);
191 }
192
193 // resize the hashmap - allocates a large table and re-hashes
194 // all entries into the new table.
195 void resize() {
196 int new_size_index = _size_index+1;
197 int new_size = _sizes[new_size_index];
198 if (new_size < 0) {
199 // hashmap already at maximum capacity
200 return;
201 }
202
203 // allocate new table
204 size_t s = new_size * sizeof(JvmtiTagHashmapEntry*);
205 JvmtiTagHashmapEntry** new_table = (JvmtiTagHashmapEntry**)os::malloc(s, mtInternal);
206 if (new_table == NULL) {
207 warning("unable to allocate larger hashtable for jvmti object tags");
208 set_resizing_enabled(false);
209 return;
210 }
211
212 // initialize new table
213 int i;
214 for (i=0; i<new_size; i++) {
215 new_table[i] = NULL;
216 }
217
218 // rehash all entries into the new table
219 for (i=0; i<_size; i++) {
220 JvmtiTagHashmapEntry* entry = _table[i];
221 while (entry != NULL) {
222 JvmtiTagHashmapEntry* next = entry->next();
223 oop key = entry->object_peek();
224 assert(key != NULL, "jni weak reference cleared!!");
225 unsigned int h = hash(key, new_size);
226 JvmtiTagHashmapEntry* anchor = new_table[h];
227 if (anchor == NULL) {
228 new_table[h] = entry;
229 entry->set_next(NULL);
230 } else {
231 entry->set_next(anchor);
232 new_table[h] = entry;
233 }
234 entry = next;
235 }
236 }
237
238 // free old table and update settings.
239 os::free((void*)_table);
240 _table = new_table;
241 _size_index = new_size_index;
242 _size = new_size;
243
244 // compute new resize threshold
245 _resize_threshold = (int)(_load_factor * _size);
246 }
247
248
249 // internal remove function - remove an entry at a given position in the
250 // table.
251 inline void remove(JvmtiTagHashmapEntry* prev, int pos, JvmtiTagHashmapEntry* entry) {
252 assert(pos >= 0 && pos < _size, "out of range");
253 if (prev == NULL) {
254 _table[pos] = entry->next();
255 } else {
256 prev->set_next(entry->next());
257 }
258 assert(_entry_count > 0, "checking");
259 _entry_count--;
260 }
261
262 // resizing switch
263 bool is_resizing_enabled() const { return _resizing_enabled; }
264 void set_resizing_enabled(bool enable) { _resizing_enabled = enable; }
265
266 // debugging
267 void print_memory_usage();
268 void compute_next_trace_threshold();
269
270 public:
271
272 // create a JvmtiTagHashmap of a preferred size and optionally a load factor.
273 // The preferred size is rounded down to an actual size.
274 JvmtiTagHashmap(int size, float load_factor=0.0f) {
275 int i=0;
276 while (_sizes[i] < size) {
277 if (_sizes[i] < 0) {
278 assert(i > 0, "sanity check");
279 i--;
280 break;
281 }
282 i++;
283 }
284
285 // if a load factor is specified then use it, otherwise use default
286 if (load_factor > 0.01f) {
287 init(i, load_factor);
288 } else {
289 init(i);
290 }
291 }
292
293 // create a JvmtiTagHashmap with default settings
294 JvmtiTagHashmap() {
295 init();
296 }
297
298 // release table when JvmtiTagHashmap destroyed
299 ~JvmtiTagHashmap() {
300 if (_table != NULL) {
301 os::free((void*)_table);
302 _table = NULL;
303 }
304 }
305
306 // accessors
307 int size() const { return _size; }
308 JvmtiTagHashmapEntry** table() const { return _table; }
309 int entry_count() const { return _entry_count; }
310
311 // find an entry in the hashmap, returns NULL if not found.
312 inline JvmtiTagHashmapEntry* find(oop key) {
313 unsigned int h = hash(key);
314 JvmtiTagHashmapEntry* entry = _table[h];
315 while (entry != NULL) {
316 if (entry->equals(key)) {
317 return entry;
318 }
319 entry = entry->next();
320 }
321 return NULL;
322 }
323
324
325 // add a new entry to hashmap
326 inline void add(oop key, JvmtiTagHashmapEntry* entry) {
327 assert(key != NULL, "checking");
328 assert(find(key) == NULL, "duplicate detected");
329 unsigned int h = hash(key);
330 JvmtiTagHashmapEntry* anchor = _table[h];
331 if (anchor == NULL) {
332 _table[h] = entry;
333 entry->set_next(NULL);
334 } else {
335 entry->set_next(anchor);
336 _table[h] = entry;
337 }
338
339 _entry_count++;
340 if (log_is_enabled(Debug, jvmti, objecttagging) && entry_count() >= trace_threshold()) {
341 print_memory_usage();
342 compute_next_trace_threshold();
343 }
344
345 // if the number of entries exceed the threshold then resize
346 if (entry_count() > resize_threshold() && is_resizing_enabled()) {
347 resize();
348 }
349 }
350
351 // remove an entry with the given key.
352 inline JvmtiTagHashmapEntry* remove(oop key) {
353 unsigned int h = hash(key);
354 JvmtiTagHashmapEntry* entry = _table[h];
355 JvmtiTagHashmapEntry* prev = NULL;
356 while (entry != NULL) {
357 if (entry->equals(key)) {
358 break;
359 }
360 prev = entry;
361 entry = entry->next();
362 }
363 if (entry != NULL) {
364 remove(prev, h, entry);
365 }
366 return entry;
367 }
368
369 // iterate over all entries in the hashmap
370 void entry_iterate(JvmtiTagHashmapEntryClosure* closure);
371 };
372
373 // possible hashmap sizes - odd primes that roughly double in size.
374 // To avoid excessive resizing the odd primes from 4801-76831 and
375 // 76831-307261 have been removed. The list must be terminated by -1.
376 int JvmtiTagHashmap::_sizes[] = { 4801, 76831, 307261, 614563, 1228891,
377 2457733, 4915219, 9830479, 19660831, 39321619, 78643219, -1 };
378
379
380 // A supporting class for iterating over all entries in Hashmap
381 class JvmtiTagHashmapEntryClosure {
382 public:
383 virtual void do_entry(JvmtiTagHashmapEntry* entry) = 0;
384 };
385
386
387 // iterate over all entries in the hashmap
388 void JvmtiTagHashmap::entry_iterate(JvmtiTagHashmapEntryClosure* closure) {
389 for (int i=0; i<_size; i++) {
390 JvmtiTagHashmapEntry* entry = _table[i];
391 JvmtiTagHashmapEntry* prev = NULL;
392 while (entry != NULL) {
393 // obtain the next entry before invoking do_entry - this is
394 // necessary because do_entry may remove the entry from the
395 // hashmap.
396 JvmtiTagHashmapEntry* next = entry->next();
397 closure->do_entry(entry);
398 entry = next;
399 }
400 }
401 }
402
403 // debugging
404 void JvmtiTagHashmap::print_memory_usage() {
405 intptr_t p = (intptr_t)this;
406 tty->print("[JvmtiTagHashmap @ " INTPTR_FORMAT, p);
407
408 // table + entries in KB
409 int hashmap_usage = (size()*sizeof(JvmtiTagHashmapEntry*) +
410 entry_count()*sizeof(JvmtiTagHashmapEntry))/K;
411
412 int weak_globals_usage = (int)(JNIHandles::weak_global_handle_memory_usage()/K);
413 tty->print_cr(", %d entries (%d KB) <JNI weak globals: %d KB>]",
414 entry_count(), hashmap_usage, weak_globals_usage);
415 }
416
417 // compute threshold for the next trace message
418 void JvmtiTagHashmap::compute_next_trace_threshold() {
419 _trace_threshold = entry_count();
420 if (trace_threshold() < medium_trace_threshold) {
421 _trace_threshold += small_trace_threshold;
422 } else {
423 if (trace_threshold() < large_trace_threshold) {
424 _trace_threshold += medium_trace_threshold;
425 } else {
426 _trace_threshold += large_trace_threshold;
427 }
428 }
429 }
430
431 // create a JvmtiTagMap
432 JvmtiTagMap::JvmtiTagMap(JvmtiEnv* env) :
433 _env(env),
434 _lock(Mutex::nonleaf+2, "JvmtiTagMap._lock", false),
435 _free_entries(NULL),
436 _free_entries_count(0)
437 {
438 assert(JvmtiThreadState_lock->is_locked(), "sanity check");
439 assert(((JvmtiEnvBase *)env)->tag_map() == NULL, "tag map already exists for environment");
440
441 _hashmap = new JvmtiTagHashmap();
442
443 // finally add us to the environment
444 ((JvmtiEnvBase *)env)->set_tag_map(this);
445 }
446
447
448 // destroy a JvmtiTagMap
449 JvmtiTagMap::~JvmtiTagMap() {
450
451 // no lock acquired as we assume the enclosing environment is
452 // also being destroryed.
453 ((JvmtiEnvBase *)_env)->set_tag_map(NULL);
454
455 JvmtiTagHashmapEntry** table = _hashmap->table();
456 for (int j = 0; j < _hashmap->size(); j++) {
457 JvmtiTagHashmapEntry* entry = table[j];
458 while (entry != NULL) {
459 JvmtiTagHashmapEntry* next = entry->next();
460 delete entry;
461 entry = next;
462 }
463 }
464
465 // finally destroy the hashmap
466 delete _hashmap;
467 _hashmap = NULL;
468
469 // remove any entries on the free list
470 JvmtiTagHashmapEntry* entry = _free_entries;
471 while (entry != NULL) {
472 JvmtiTagHashmapEntry* next = entry->next();
473 delete entry;
474 entry = next;
475 }
476 _free_entries = NULL;
477 }
478
479 // create a hashmap entry
480 // - if there's an entry on the (per-environment) free list then this
481 // is returned. Otherwise an new entry is allocated.
482 JvmtiTagHashmapEntry* JvmtiTagMap::create_entry(oop ref, jlong tag) {
483 assert(Thread::current()->is_VM_thread() || is_locked(), "checking");
484 JvmtiTagHashmapEntry* entry;
485 if (_free_entries == NULL) {
486 entry = new JvmtiTagHashmapEntry(ref, tag);
487 } else {
488 assert(_free_entries_count > 0, "mismatched _free_entries_count");
489 _free_entries_count--;
490 entry = _free_entries;
491 _free_entries = entry->next();
492 entry->init(ref, tag);
493 }
494 return entry;
495 }
496
497 // destroy an entry by returning it to the free list
498 void JvmtiTagMap::destroy_entry(JvmtiTagHashmapEntry* entry) {
499 assert(SafepointSynchronize::is_at_safepoint() || is_locked(), "checking");
500 // limit the size of the free list
501 if (_free_entries_count >= max_free_entries) {
502 delete entry;
503 } else {
504 entry->set_next(_free_entries);
505 _free_entries = entry;
506 _free_entries_count++;
507 }
508 }
509
510 // returns the tag map for the given environments. If the tag map
511 // doesn't exist then it is created.
512 JvmtiTagMap* JvmtiTagMap::tag_map_for(JvmtiEnv* env) {
513 JvmtiTagMap* tag_map = ((JvmtiEnvBase*)env)->tag_map();
514 if (tag_map == NULL) {
515 MutexLocker mu(JvmtiThreadState_lock);
516 tag_map = ((JvmtiEnvBase*)env)->tag_map();
517 if (tag_map == NULL) {
518 tag_map = new JvmtiTagMap(env);
519 }
520 } else {
521 CHECK_UNHANDLED_OOPS_ONLY(Thread::current()->clear_unhandled_oops());
522 }
523 return tag_map;
524 }
525
526 // iterate over all entries in the tag map.
527 void JvmtiTagMap::entry_iterate(JvmtiTagHashmapEntryClosure* closure) {
528 hashmap()->entry_iterate(closure);
529 }
530
531 // returns true if the hashmaps are empty
532 bool JvmtiTagMap::is_empty() {
533 assert(SafepointSynchronize::is_at_safepoint() || is_locked(), "checking");
534 return hashmap()->entry_count() == 0;
535 }
536
537
538 // Return the tag value for an object, or 0 if the object is
539 // not tagged
540 //
541 static inline jlong tag_for(JvmtiTagMap* tag_map, oop o) {
542 JvmtiTagHashmapEntry* entry = tag_map->hashmap()->find(o);
543 if (entry == NULL) {
544 return 0;
545 } else {
546 return entry->tag();
547 }
548 }
549
550
551 // A CallbackWrapper is a support class for querying and tagging an object
552 // around a callback to a profiler. The constructor does pre-callback
553 // work to get the tag value, klass tag value, ... and the destructor
554 // does the post-callback work of tagging or untagging the object.
555 //
556 // {
557 // CallbackWrapper wrapper(tag_map, o);
558 //
559 // (*callback)(wrapper.klass_tag(), wrapper.obj_size(), wrapper.obj_tag_p(), ...)
560 //
561 // } // wrapper goes out of scope here which results in the destructor
562 // checking to see if the object has been tagged, untagged, or the
563 // tag value has changed.
564 //
565 class CallbackWrapper : public StackObj {
566 private:
567 JvmtiTagMap* _tag_map;
568 JvmtiTagHashmap* _hashmap;
569 JvmtiTagHashmapEntry* _entry;
570 oop _o;
571 jlong _obj_size;
572 jlong _obj_tag;
573 jlong _klass_tag;
574
575 protected:
576 JvmtiTagMap* tag_map() const { return _tag_map; }
577
578 // invoked post-callback to tag, untag, or update the tag of an object
579 void inline post_callback_tag_update(oop o, JvmtiTagHashmap* hashmap,
580 JvmtiTagHashmapEntry* entry, jlong obj_tag);
581 public:
582 CallbackWrapper(JvmtiTagMap* tag_map, oop o) {
583 assert(Thread::current()->is_VM_thread() || tag_map->is_locked(),
584 "MT unsafe or must be VM thread");
585
586 // object to tag
587 _o = o;
588
589 // object size
590 _obj_size = (jlong)_o->size() * wordSize;
591
592 // record the context
593 _tag_map = tag_map;
594 _hashmap = tag_map->hashmap();
595 _entry = _hashmap->find(_o);
596
597 // get object tag
598 _obj_tag = (_entry == NULL) ? 0 : _entry->tag();
599
600 // get the class and the class's tag value
601 assert(SystemDictionary::Class_klass()->is_mirror_instance_klass(), "Is not?");
602
603 _klass_tag = tag_for(tag_map, _o->klass()->java_mirror());
604 }
605
606 ~CallbackWrapper() {
607 post_callback_tag_update(_o, _hashmap, _entry, _obj_tag);
608 }
609
610 inline jlong* obj_tag_p() { return &_obj_tag; }
611 inline jlong obj_size() const { return _obj_size; }
612 inline jlong obj_tag() const { return _obj_tag; }
613 inline jlong klass_tag() const { return _klass_tag; }
614 };
615
616
617
618 // callback post-callback to tag, untag, or update the tag of an object
619 void inline CallbackWrapper::post_callback_tag_update(oop o,
620 JvmtiTagHashmap* hashmap,
621 JvmtiTagHashmapEntry* entry,
622 jlong obj_tag) {
623 if (entry == NULL) {
624 if (obj_tag != 0) {
625 // callback has tagged the object
626 assert(Thread::current()->is_VM_thread(), "must be VMThread");
627 entry = tag_map()->create_entry(o, obj_tag);
628 hashmap->add(o, entry);
629 }
630 } else {
631 // object was previously tagged - the callback may have untagged
632 // the object or changed the tag value
633 if (obj_tag == 0) {
634
635 JvmtiTagHashmapEntry* entry_removed = hashmap->remove(o);
636 assert(entry_removed == entry, "checking");
637 tag_map()->destroy_entry(entry);
638
639 } else {
640 if (obj_tag != entry->tag()) {
641 entry->set_tag(obj_tag);
642 }
643 }
644 }
645 }
646
647 // An extended CallbackWrapper used when reporting an object reference
648 // to the agent.
649 //
650 // {
651 // TwoOopCallbackWrapper wrapper(tag_map, referrer, o);
652 //
653 // (*callback)(wrapper.klass_tag(),
654 // wrapper.obj_size(),
655 // wrapper.obj_tag_p()
656 // wrapper.referrer_tag_p(), ...)
657 //
658 // } // wrapper goes out of scope here which results in the destructor
659 // checking to see if the referrer object has been tagged, untagged,
660 // or the tag value has changed.
661 //
662 class TwoOopCallbackWrapper : public CallbackWrapper {
663 private:
664 bool _is_reference_to_self;
665 JvmtiTagHashmap* _referrer_hashmap;
666 JvmtiTagHashmapEntry* _referrer_entry;
667 oop _referrer;
668 jlong _referrer_obj_tag;
669 jlong _referrer_klass_tag;
670 jlong* _referrer_tag_p;
671
672 bool is_reference_to_self() const { return _is_reference_to_self; }
673
674 public:
675 TwoOopCallbackWrapper(JvmtiTagMap* tag_map, oop referrer, oop o) :
676 CallbackWrapper(tag_map, o)
677 {
678 // self reference needs to be handled in a special way
679 _is_reference_to_self = (referrer == o);
680
681 if (_is_reference_to_self) {
682 _referrer_klass_tag = klass_tag();
683 _referrer_tag_p = obj_tag_p();
684 } else {
685 _referrer = referrer;
686 // record the context
687 _referrer_hashmap = tag_map->hashmap();
688 _referrer_entry = _referrer_hashmap->find(_referrer);
689
690 // get object tag
691 _referrer_obj_tag = (_referrer_entry == NULL) ? 0 : _referrer_entry->tag();
692 _referrer_tag_p = &_referrer_obj_tag;
693
694 // get referrer class tag.
695 _referrer_klass_tag = tag_for(tag_map, _referrer->klass()->java_mirror());
696 }
697 }
698
699 ~TwoOopCallbackWrapper() {
700 if (!is_reference_to_self()){
701 post_callback_tag_update(_referrer,
702 _referrer_hashmap,
703 _referrer_entry,
704 _referrer_obj_tag);
705 }
706 }
707
708 // address of referrer tag
709 // (for a self reference this will return the same thing as obj_tag_p())
710 inline jlong* referrer_tag_p() { return _referrer_tag_p; }
711
712 // referrer's class tag
713 inline jlong referrer_klass_tag() { return _referrer_klass_tag; }
714 };
715
716 // tag an object
717 //
718 // This function is performance critical. If many threads attempt to tag objects
719 // around the same time then it's possible that the Mutex associated with the
720 // tag map will be a hot lock.
721 void JvmtiTagMap::set_tag(jobject object, jlong tag) {
722 MutexLocker ml(lock());
723
724 // resolve the object
725 oop o = JNIHandles::resolve_non_null(object);
726
727 // see if the object is already tagged
728 JvmtiTagHashmap* hashmap = _hashmap;
729 JvmtiTagHashmapEntry* entry = hashmap->find(o);
730
731 // if the object is not already tagged then we tag it
732 if (entry == NULL) {
733 if (tag != 0) {
734 entry = create_entry(o, tag);
735 hashmap->add(o, entry);
736 } else {
737 // no-op
738 }
739 } else {
740 // if the object is already tagged then we either update
741 // the tag (if a new tag value has been provided)
742 // or remove the object if the new tag value is 0.
743 if (tag == 0) {
744 hashmap->remove(o);
745 destroy_entry(entry);
746 } else {
747 entry->set_tag(tag);
748 }
749 }
750 }
751
752 // get the tag for an object
753 jlong JvmtiTagMap::get_tag(jobject object) {
754 MutexLocker ml(lock());
755
756 // resolve the object
757 oop o = JNIHandles::resolve_non_null(object);
758
759 return tag_for(this, o);
760 }
761
762
763 // Helper class used to describe the static or instance fields of a class.
764 // For each field it holds the field index (as defined by the JVMTI specification),
765 // the field type, and the offset.
766
767 class ClassFieldDescriptor: public CHeapObj<mtInternal> {
768 private:
769 int _field_index;
770 int _field_offset;
771 char _field_type;
772 public:
773 ClassFieldDescriptor(int index, char type, int offset) :
774 _field_index(index), _field_type(type), _field_offset(offset) {
775 }
776 int field_index() const { return _field_index; }
777 char field_type() const { return _field_type; }
778 int field_offset() const { return _field_offset; }
779 };
780
781 class ClassFieldMap: public CHeapObj<mtInternal> {
782 private:
783 enum {
784 initial_field_count = 5
785 };
786
787 // list of field descriptors
788 GrowableArray<ClassFieldDescriptor*>* _fields;
789
790 // constructor
791 ClassFieldMap();
792
793 // add a field
794 void add(int index, char type, int offset);
795
796 // returns the field count for the given class
797 static int compute_field_count(InstanceKlass* ik);
798
799 public:
800 ~ClassFieldMap();
801
802 // access
803 int field_count() { return _fields->length(); }
804 ClassFieldDescriptor* field_at(int i) { return _fields->at(i); }
805
806 // functions to create maps of static or instance fields
807 static ClassFieldMap* create_map_of_static_fields(Klass* k);
808 static ClassFieldMap* create_map_of_instance_fields(oop obj);
809 };
810
811 ClassFieldMap::ClassFieldMap() {
812 _fields = new (ResourceObj::C_HEAP, mtInternal)
813 GrowableArray<ClassFieldDescriptor*>(initial_field_count, true);
814 }
815
816 ClassFieldMap::~ClassFieldMap() {
817 for (int i=0; i<_fields->length(); i++) {
818 delete _fields->at(i);
819 }
820 delete _fields;
821 }
822
823 void ClassFieldMap::add(int index, char type, int offset) {
824 ClassFieldDescriptor* field = new ClassFieldDescriptor(index, type, offset);
825 _fields->append(field);
826 }
827
828 // Returns a heap allocated ClassFieldMap to describe the static fields
829 // of the given class.
830 //
831 ClassFieldMap* ClassFieldMap::create_map_of_static_fields(Klass* k) {
832 HandleMark hm;
833 InstanceKlass* ik = InstanceKlass::cast(k);
834
835 // create the field map
836 ClassFieldMap* field_map = new ClassFieldMap();
837
838 FilteredFieldStream f(ik, false, false);
839 int max_field_index = f.field_count()-1;
840
841 int index = 0;
842 for (FilteredFieldStream fld(ik, true, true); !fld.eos(); fld.next(), index++) {
843 // ignore instance fields
844 if (!fld.access_flags().is_static()) {
845 continue;
846 }
847 field_map->add(max_field_index - index, fld.signature()->byte_at(0), fld.offset());
848 }
849 return field_map;
850 }
851
852 // Returns a heap allocated ClassFieldMap to describe the instance fields
853 // of the given class. All instance fields are included (this means public
854 // and private fields declared in superclasses and superinterfaces too).
855 //
856 ClassFieldMap* ClassFieldMap::create_map_of_instance_fields(oop obj) {
857 HandleMark hm;
858 InstanceKlass* ik = InstanceKlass::cast(obj->klass());
859
860 // create the field map
861 ClassFieldMap* field_map = new ClassFieldMap();
862
863 FilteredFieldStream f(ik, false, false);
864
865 int max_field_index = f.field_count()-1;
866
867 int index = 0;
868 for (FilteredFieldStream fld(ik, false, false); !fld.eos(); fld.next(), index++) {
869 // ignore static fields
870 if (fld.access_flags().is_static()) {
871 continue;
872 }
873 field_map->add(max_field_index - index, fld.signature()->byte_at(0), fld.offset());
874 }
875
876 return field_map;
877 }
878
879 // Helper class used to cache a ClassFileMap for the instance fields of
880 // a cache. A JvmtiCachedClassFieldMap can be cached by an InstanceKlass during
881 // heap iteration and avoid creating a field map for each object in the heap
882 // (only need to create the map when the first instance of a class is encountered).
883 //
884 class JvmtiCachedClassFieldMap : public CHeapObj<mtInternal> {
885 private:
886 enum {
887 initial_class_count = 200
888 };
889 ClassFieldMap* _field_map;
890
891 ClassFieldMap* field_map() const { return _field_map; }
892
893 JvmtiCachedClassFieldMap(ClassFieldMap* field_map);
894 ~JvmtiCachedClassFieldMap();
895
896 static GrowableArray<InstanceKlass*>* _class_list;
897 static void add_to_class_list(InstanceKlass* ik);
898
899 public:
900 // returns the field map for a given object (returning map cached
901 // by InstanceKlass if possible
902 static ClassFieldMap* get_map_of_instance_fields(oop obj);
903
904 // removes the field map from all instanceKlasses - should be
905 // called before VM operation completes
906 static void clear_cache();
907
908 // returns the number of ClassFieldMap cached by instanceKlasses
909 static int cached_field_map_count();
910 };
911
912 GrowableArray<InstanceKlass*>* JvmtiCachedClassFieldMap::_class_list;
913
914 JvmtiCachedClassFieldMap::JvmtiCachedClassFieldMap(ClassFieldMap* field_map) {
915 _field_map = field_map;
916 }
917
918 JvmtiCachedClassFieldMap::~JvmtiCachedClassFieldMap() {
919 if (_field_map != NULL) {
920 delete _field_map;
921 }
922 }
923
924 // Marker class to ensure that the class file map cache is only used in a defined
925 // scope.
926 class ClassFieldMapCacheMark : public StackObj {
927 private:
928 static bool _is_active;
929 public:
930 ClassFieldMapCacheMark() {
931 assert(Thread::current()->is_VM_thread(), "must be VMThread");
932 assert(JvmtiCachedClassFieldMap::cached_field_map_count() == 0, "cache not empty");
933 assert(!_is_active, "ClassFieldMapCacheMark cannot be nested");
934 _is_active = true;
935 }
936 ~ClassFieldMapCacheMark() {
937 JvmtiCachedClassFieldMap::clear_cache();
938 _is_active = false;
939 }
940 static bool is_active() { return _is_active; }
941 };
942
943 bool ClassFieldMapCacheMark::_is_active;
944
945
946 // record that the given InstanceKlass is caching a field map
947 void JvmtiCachedClassFieldMap::add_to_class_list(InstanceKlass* ik) {
948 if (_class_list == NULL) {
949 _class_list = new (ResourceObj::C_HEAP, mtInternal)
950 GrowableArray<InstanceKlass*>(initial_class_count, true);
951 }
952 _class_list->push(ik);
953 }
954
955 // returns the instance field map for the given object
956 // (returns field map cached by the InstanceKlass if possible)
957 ClassFieldMap* JvmtiCachedClassFieldMap::get_map_of_instance_fields(oop obj) {
958 assert(Thread::current()->is_VM_thread(), "must be VMThread");
959 assert(ClassFieldMapCacheMark::is_active(), "ClassFieldMapCacheMark not active");
960
961 Klass* k = obj->klass();
962 InstanceKlass* ik = InstanceKlass::cast(k);
963
964 // return cached map if possible
965 JvmtiCachedClassFieldMap* cached_map = ik->jvmti_cached_class_field_map();
966 if (cached_map != NULL) {
967 assert(cached_map->field_map() != NULL, "missing field list");
968 return cached_map->field_map();
969 } else {
970 ClassFieldMap* field_map = ClassFieldMap::create_map_of_instance_fields(obj);
971 cached_map = new JvmtiCachedClassFieldMap(field_map);
972 ik->set_jvmti_cached_class_field_map(cached_map);
973 add_to_class_list(ik);
974 return field_map;
975 }
976 }
977
978 // remove the fields maps cached from all instanceKlasses
979 void JvmtiCachedClassFieldMap::clear_cache() {
980 assert(Thread::current()->is_VM_thread(), "must be VMThread");
981 if (_class_list != NULL) {
982 for (int i = 0; i < _class_list->length(); i++) {
983 InstanceKlass* ik = _class_list->at(i);
984 JvmtiCachedClassFieldMap* cached_map = ik->jvmti_cached_class_field_map();
985 assert(cached_map != NULL, "should not be NULL");
986 ik->set_jvmti_cached_class_field_map(NULL);
987 delete cached_map; // deletes the encapsulated field map
988 }
989 delete _class_list;
990 _class_list = NULL;
991 }
992 }
993
994 // returns the number of ClassFieldMap cached by instanceKlasses
995 int JvmtiCachedClassFieldMap::cached_field_map_count() {
996 return (_class_list == NULL) ? 0 : _class_list->length();
997 }
998
999 // helper function to indicate if an object is filtered by its tag or class tag
1000 static inline bool is_filtered_by_heap_filter(jlong obj_tag,
1001 jlong klass_tag,
1002 int heap_filter) {
1003 // apply the heap filter
1004 if (obj_tag != 0) {
1005 // filter out tagged objects
1006 if (heap_filter & JVMTI_HEAP_FILTER_TAGGED) return true;
1007 } else {
1008 // filter out untagged objects
1009 if (heap_filter & JVMTI_HEAP_FILTER_UNTAGGED) return true;
1010 }
1011 if (klass_tag != 0) {
1012 // filter out objects with tagged classes
1013 if (heap_filter & JVMTI_HEAP_FILTER_CLASS_TAGGED) return true;
1014 } else {
1015 // filter out objects with untagged classes.
1016 if (heap_filter & JVMTI_HEAP_FILTER_CLASS_UNTAGGED) return true;
1017 }
1018 return false;
1019 }
1020
1021 // helper function to indicate if an object is filtered by a klass filter
1022 static inline bool is_filtered_by_klass_filter(oop obj, Klass* klass_filter) {
1023 if (klass_filter != NULL) {
1024 if (obj->klass() != klass_filter) {
1025 return true;
1026 }
1027 }
1028 return false;
1029 }
1030
1031 // helper function to tell if a field is a primitive field or not
1032 static inline bool is_primitive_field_type(char type) {
1033 return (type != 'L' && type != '[');
1034 }
1035
1036 // helper function to copy the value from location addr to jvalue.
1037 static inline void copy_to_jvalue(jvalue *v, address addr, jvmtiPrimitiveType value_type) {
1038 switch (value_type) {
1039 case JVMTI_PRIMITIVE_TYPE_BOOLEAN : { v->z = *(jboolean*)addr; break; }
1040 case JVMTI_PRIMITIVE_TYPE_BYTE : { v->b = *(jbyte*)addr; break; }
1041 case JVMTI_PRIMITIVE_TYPE_CHAR : { v->c = *(jchar*)addr; break; }
1042 case JVMTI_PRIMITIVE_TYPE_SHORT : { v->s = *(jshort*)addr; break; }
1043 case JVMTI_PRIMITIVE_TYPE_INT : { v->i = *(jint*)addr; break; }
1044 case JVMTI_PRIMITIVE_TYPE_LONG : { v->j = *(jlong*)addr; break; }
1045 case JVMTI_PRIMITIVE_TYPE_FLOAT : { v->f = *(jfloat*)addr; break; }
1046 case JVMTI_PRIMITIVE_TYPE_DOUBLE : { v->d = *(jdouble*)addr; break; }
1047 default: ShouldNotReachHere();
1048 }
1049 }
1050
1051 // helper function to invoke string primitive value callback
1052 // returns visit control flags
1053 static jint invoke_string_value_callback(jvmtiStringPrimitiveValueCallback cb,
1054 CallbackWrapper* wrapper,
1055 oop str,
1056 void* user_data)
1057 {
1058 assert(str->klass() == SystemDictionary::String_klass(), "not a string");
1059
1060 typeArrayOop s_value = java_lang_String::value(str);
1061
1062 // JDK-6584008: the value field may be null if a String instance is
1063 // partially constructed.
1064 if (s_value == NULL) {
1065 return 0;
1066 }
1067 // get the string value and length
1068 // (string value may be offset from the base)
1069 int s_len = java_lang_String::length(str);
1070 bool is_latin1 = java_lang_String::is_latin1(str);
1071 jchar* value;
1072 if (s_len > 0) {
1073 if (!is_latin1) {
1074 value = s_value->char_at_addr(0);
1075 } else {
1076 // Inflate latin1 encoded string to UTF16
1077 jchar* buf = NEW_C_HEAP_ARRAY(jchar, s_len, mtInternal);
1078 for (int i = 0; i < s_len; i++) {
1079 buf[i] = ((jchar) s_value->byte_at(i)) & 0xff;
1080 }
1081 value = &buf[0];
1082 }
1083 } else {
1084 // Don't use char_at_addr(0) if length is 0
1085 value = (jchar*) s_value->base(T_CHAR);
1086 }
1087
1088 // invoke the callback
1089 jint res = (*cb)(wrapper->klass_tag(),
1090 wrapper->obj_size(),
1091 wrapper->obj_tag_p(),
1092 value,
1093 (jint)s_len,
1094 user_data);
1095
1096 if (is_latin1 && s_len > 0) {
1097 FREE_C_HEAP_ARRAY(jchar, value);
1098 }
1099 return res;
1100 }
1101
1102 // helper function to invoke string primitive value callback
1103 // returns visit control flags
1104 static jint invoke_array_primitive_value_callback(jvmtiArrayPrimitiveValueCallback cb,
1105 CallbackWrapper* wrapper,
1106 oop obj,
1107 void* user_data)
1108 {
1109 assert(obj->is_typeArray(), "not a primitive array");
1110
1111 // get base address of first element
1112 typeArrayOop array = typeArrayOop(obj);
1113 BasicType type = TypeArrayKlass::cast(array->klass())->element_type();
1114 void* elements = array->base(type);
1115
1116 // jvmtiPrimitiveType is defined so this mapping is always correct
1117 jvmtiPrimitiveType elem_type = (jvmtiPrimitiveType)type2char(type);
1118
1119 return (*cb)(wrapper->klass_tag(),
1120 wrapper->obj_size(),
1121 wrapper->obj_tag_p(),
1122 (jint)array->length(),
1123 elem_type,
1124 elements,
1125 user_data);
1126 }
1127
1128 // helper function to invoke the primitive field callback for all static fields
1129 // of a given class
1130 static jint invoke_primitive_field_callback_for_static_fields
1131 (CallbackWrapper* wrapper,
1132 oop obj,
1133 jvmtiPrimitiveFieldCallback cb,
1134 void* user_data)
1135 {
1136 // for static fields only the index will be set
1137 static jvmtiHeapReferenceInfo reference_info = { 0 };
1138
1139 assert(obj->klass() == SystemDictionary::Class_klass(), "not a class");
1140 if (java_lang_Class::is_primitive(obj)) {
1141 return 0;
1142 }
1143 Klass* klass = java_lang_Class::as_Klass(obj);
1144
1145 // ignore classes for object and type arrays
1146 if (!klass->is_instance_klass()) {
1147 return 0;
1148 }
1149
1150 // ignore classes which aren't linked yet
1151 InstanceKlass* ik = InstanceKlass::cast(klass);
1152 if (!ik->is_linked()) {
1153 return 0;
1154 }
1155
1156 // get the field map
1157 ClassFieldMap* field_map = ClassFieldMap::create_map_of_static_fields(klass);
1158
1159 // invoke the callback for each static primitive field
1160 for (int i=0; i<field_map->field_count(); i++) {
1161 ClassFieldDescriptor* field = field_map->field_at(i);
1162
1163 // ignore non-primitive fields
1164 char type = field->field_type();
1165 if (!is_primitive_field_type(type)) {
1166 continue;
1167 }
1168 // one-to-one mapping
1169 jvmtiPrimitiveType value_type = (jvmtiPrimitiveType)type;
1170
1171 // get offset and field value
1172 int offset = field->field_offset();
1173 address addr = (address)klass->java_mirror() + offset;
1174 jvalue value;
1175 copy_to_jvalue(&value, addr, value_type);
1176
1177 // field index
1178 reference_info.field.index = field->field_index();
1179
1180 // invoke the callback
1181 jint res = (*cb)(JVMTI_HEAP_REFERENCE_STATIC_FIELD,
1182 &reference_info,
1183 wrapper->klass_tag(),
1184 wrapper->obj_tag_p(),
1185 value,
1186 value_type,
1187 user_data);
1188 if (res & JVMTI_VISIT_ABORT) {
1189 delete field_map;
1190 return res;
1191 }
1192 }
1193
1194 delete field_map;
1195 return 0;
1196 }
1197
1198 // helper function to invoke the primitive field callback for all instance fields
1199 // of a given object
1200 static jint invoke_primitive_field_callback_for_instance_fields(
1201 CallbackWrapper* wrapper,
1202 oop obj,
1203 jvmtiPrimitiveFieldCallback cb,
1204 void* user_data)
1205 {
1206 // for instance fields only the index will be set
1207 static jvmtiHeapReferenceInfo reference_info = { 0 };
1208
1209 // get the map of the instance fields
1210 ClassFieldMap* fields = JvmtiCachedClassFieldMap::get_map_of_instance_fields(obj);
1211
1212 // invoke the callback for each instance primitive field
1213 for (int i=0; i<fields->field_count(); i++) {
1214 ClassFieldDescriptor* field = fields->field_at(i);
1215
1216 // ignore non-primitive fields
1217 char type = field->field_type();
1218 if (!is_primitive_field_type(type)) {
1219 continue;
1220 }
1221 // one-to-one mapping
1222 jvmtiPrimitiveType value_type = (jvmtiPrimitiveType)type;
1223
1224 // get offset and field value
1225 int offset = field->field_offset();
1226 address addr = (address)obj + offset;
1227 jvalue value;
1228 copy_to_jvalue(&value, addr, value_type);
1229
1230 // field index
1231 reference_info.field.index = field->field_index();
1232
1233 // invoke the callback
1234 jint res = (*cb)(JVMTI_HEAP_REFERENCE_FIELD,
1235 &reference_info,
1236 wrapper->klass_tag(),
1237 wrapper->obj_tag_p(),
1238 value,
1239 value_type,
1240 user_data);
1241 if (res & JVMTI_VISIT_ABORT) {
1242 return res;
1243 }
1244 }
1245 return 0;
1246 }
1247
1248
1249 // VM operation to iterate over all objects in the heap (both reachable
1250 // and unreachable)
1251 class VM_HeapIterateOperation: public VM_Operation {
1252 private:
1253 ObjectClosure* _blk;
1254 public:
1255 VM_HeapIterateOperation(ObjectClosure* blk) { _blk = blk; }
1256
1257 VMOp_Type type() const { return VMOp_HeapIterateOperation; }
1258 void doit() {
1259 // allows class files maps to be cached during iteration
1260 ClassFieldMapCacheMark cm;
1261
1262 // make sure that heap is parsable (fills TLABs with filler objects)
1263 Universe::heap()->ensure_parsability(false); // no need to retire TLABs
1264
1265 // Verify heap before iteration - if the heap gets corrupted then
1266 // JVMTI's IterateOverHeap will crash.
1267 if (VerifyBeforeIteration) {
1268 Universe::verify();
1269 }
1270
1271 // do the iteration
1272 // If this operation encounters a bad object when using CMS,
1273 // consider using safe_object_iterate() which avoids perm gen
1274 // objects that may contain bad references.
1275 Universe::heap()->object_iterate(_blk);
1276 }
1277
1278 };
1279
1280
1281 // An ObjectClosure used to support the deprecated IterateOverHeap and
1282 // IterateOverInstancesOfClass functions
1283 class IterateOverHeapObjectClosure: public ObjectClosure {
1284 private:
1285 JvmtiTagMap* _tag_map;
1286 Klass* _klass;
1287 jvmtiHeapObjectFilter _object_filter;
1288 jvmtiHeapObjectCallback _heap_object_callback;
1289 const void* _user_data;
1290
1291 // accessors
1292 JvmtiTagMap* tag_map() const { return _tag_map; }
1293 jvmtiHeapObjectFilter object_filter() const { return _object_filter; }
1294 jvmtiHeapObjectCallback object_callback() const { return _heap_object_callback; }
1295 Klass* klass() const { return _klass; }
1296 const void* user_data() const { return _user_data; }
1297
1298 // indicates if iteration has been aborted
1299 bool _iteration_aborted;
1300 bool is_iteration_aborted() const { return _iteration_aborted; }
1301 void set_iteration_aborted(bool aborted) { _iteration_aborted = aborted; }
1302
1303 public:
1304 IterateOverHeapObjectClosure(JvmtiTagMap* tag_map,
1305 Klass* klass,
1306 jvmtiHeapObjectFilter object_filter,
1307 jvmtiHeapObjectCallback heap_object_callback,
1308 const void* user_data) :
1309 _tag_map(tag_map),
1310 _klass(klass),
1311 _object_filter(object_filter),
1312 _heap_object_callback(heap_object_callback),
1313 _user_data(user_data),
1314 _iteration_aborted(false)
1315 {
1316 }
1317
1318 void do_object(oop o);
1319 };
1320
1321 // invoked for each object in the heap
1322 void IterateOverHeapObjectClosure::do_object(oop o) {
1323 // check if iteration has been halted
1324 if (is_iteration_aborted()) return;
1325
1326 // instanceof check when filtering by klass
1327 if (klass() != NULL && !o->is_a(klass())) {
1328 return;
1329 }
1330 // prepare for the calllback
1331 CallbackWrapper wrapper(tag_map(), o);
1332
1333 // if the object is tagged and we're only interested in untagged objects
1334 // then don't invoke the callback. Similiarly, if the object is untagged
1335 // and we're only interested in tagged objects we skip the callback.
1336 if (wrapper.obj_tag() != 0) {
1337 if (object_filter() == JVMTI_HEAP_OBJECT_UNTAGGED) return;
1338 } else {
1339 if (object_filter() == JVMTI_HEAP_OBJECT_TAGGED) return;
1340 }
1341
1342 // invoke the agent's callback
1343 jvmtiIterationControl control = (*object_callback())(wrapper.klass_tag(),
1344 wrapper.obj_size(),
1345 wrapper.obj_tag_p(),
1346 (void*)user_data());
1347 if (control == JVMTI_ITERATION_ABORT) {
1348 set_iteration_aborted(true);
1349 }
1350 }
1351
1352 // An ObjectClosure used to support the IterateThroughHeap function
1353 class IterateThroughHeapObjectClosure: public ObjectClosure {
1354 private:
1355 JvmtiTagMap* _tag_map;
1356 Klass* _klass;
1357 int _heap_filter;
1358 const jvmtiHeapCallbacks* _callbacks;
1359 const void* _user_data;
1360
1361 // accessor functions
1362 JvmtiTagMap* tag_map() const { return _tag_map; }
1363 int heap_filter() const { return _heap_filter; }
1364 const jvmtiHeapCallbacks* callbacks() const { return _callbacks; }
1365 Klass* klass() const { return _klass; }
1366 const void* user_data() const { return _user_data; }
1367
1368 // indicates if the iteration has been aborted
1369 bool _iteration_aborted;
1370 bool is_iteration_aborted() const { return _iteration_aborted; }
1371
1372 // used to check the visit control flags. If the abort flag is set
1373 // then we set the iteration aborted flag so that the iteration completes
1374 // without processing any further objects
1375 bool check_flags_for_abort(jint flags) {
1376 bool is_abort = (flags & JVMTI_VISIT_ABORT) != 0;
1377 if (is_abort) {
1378 _iteration_aborted = true;
1379 }
1380 return is_abort;
1381 }
1382
1383 public:
1384 IterateThroughHeapObjectClosure(JvmtiTagMap* tag_map,
1385 Klass* klass,
1386 int heap_filter,
1387 const jvmtiHeapCallbacks* heap_callbacks,
1388 const void* user_data) :
1389 _tag_map(tag_map),
1390 _klass(klass),
1391 _heap_filter(heap_filter),
1392 _callbacks(heap_callbacks),
1393 _user_data(user_data),
1394 _iteration_aborted(false)
1395 {
1396 }
1397
1398 void do_object(oop o);
1399 };
1400
1401 // invoked for each object in the heap
1402 void IterateThroughHeapObjectClosure::do_object(oop obj) {
1403 // check if iteration has been halted
1404 if (is_iteration_aborted()) return;
1405
1406 // apply class filter
1407 if (is_filtered_by_klass_filter(obj, klass())) return;
1408
1409 // prepare for callback
1410 CallbackWrapper wrapper(tag_map(), obj);
1411
1412 // check if filtered by the heap filter
1413 if (is_filtered_by_heap_filter(wrapper.obj_tag(), wrapper.klass_tag(), heap_filter())) {
1414 return;
1415 }
1416
1417 // for arrays we need the length, otherwise -1
1418 bool is_array = obj->is_array();
1419 int len = is_array ? arrayOop(obj)->length() : -1;
1420
1421 // invoke the object callback (if callback is provided)
1422 if (callbacks()->heap_iteration_callback != NULL) {
1423 jvmtiHeapIterationCallback cb = callbacks()->heap_iteration_callback;
1424 jint res = (*cb)(wrapper.klass_tag(),
1425 wrapper.obj_size(),
1426 wrapper.obj_tag_p(),
1427 (jint)len,
1428 (void*)user_data());
1429 if (check_flags_for_abort(res)) return;
1430 }
1431
1432 // for objects and classes we report primitive fields if callback provided
1433 if (callbacks()->primitive_field_callback != NULL && obj->is_instance()) {
1434 jint res;
1435 jvmtiPrimitiveFieldCallback cb = callbacks()->primitive_field_callback;
1436 if (obj->klass() == SystemDictionary::Class_klass()) {
1437 res = invoke_primitive_field_callback_for_static_fields(&wrapper,
1438 obj,
1439 cb,
1440 (void*)user_data());
1441 } else {
1442 res = invoke_primitive_field_callback_for_instance_fields(&wrapper,
1443 obj,
1444 cb,
1445 (void*)user_data());
1446 }
1447 if (check_flags_for_abort(res)) return;
1448 }
1449
1450 // string callback
1451 if (!is_array &&
1452 callbacks()->string_primitive_value_callback != NULL &&
1453 obj->klass() == SystemDictionary::String_klass()) {
1454 jint res = invoke_string_value_callback(
1455 callbacks()->string_primitive_value_callback,
1456 &wrapper,
1457 obj,
1458 (void*)user_data() );
1459 if (check_flags_for_abort(res)) return;
1460 }
1461
1462 // array callback
1463 if (is_array &&
1464 callbacks()->array_primitive_value_callback != NULL &&
1465 obj->is_typeArray()) {
1466 jint res = invoke_array_primitive_value_callback(
1467 callbacks()->array_primitive_value_callback,
1468 &wrapper,
1469 obj,
1470 (void*)user_data() );
1471 if (check_flags_for_abort(res)) return;
1472 }
1473 };
1474
1475
1476 // Deprecated function to iterate over all objects in the heap
1477 void JvmtiTagMap::iterate_over_heap(jvmtiHeapObjectFilter object_filter,
1478 Klass* klass,
1479 jvmtiHeapObjectCallback heap_object_callback,
1480 const void* user_data)
1481 {
1482 MutexLocker ml(Heap_lock);
1483 IterateOverHeapObjectClosure blk(this,
1484 klass,
1485 object_filter,
1486 heap_object_callback,
1487 user_data);
1488 VM_HeapIterateOperation op(&blk);
1489 VMThread::execute(&op);
1490 }
1491
1492
1493 // Iterates over all objects in the heap
1494 void JvmtiTagMap::iterate_through_heap(jint heap_filter,
1495 Klass* klass,
1496 const jvmtiHeapCallbacks* callbacks,
1497 const void* user_data)
1498 {
1499 MutexLocker ml(Heap_lock);
1500 IterateThroughHeapObjectClosure blk(this,
1501 klass,
1502 heap_filter,
1503 callbacks,
1504 user_data);
1505 VM_HeapIterateOperation op(&blk);
1506 VMThread::execute(&op);
1507 }
1508
1509 // support class for get_objects_with_tags
1510
1511 class TagObjectCollector : public JvmtiTagHashmapEntryClosure {
1512 private:
1513 JvmtiEnv* _env;
1514 jlong* _tags;
1515 jint _tag_count;
1516
1517 GrowableArray<jobject>* _object_results; // collected objects (JNI weak refs)
1518 GrowableArray<uint64_t>* _tag_results; // collected tags
1519
1520 public:
1521 TagObjectCollector(JvmtiEnv* env, const jlong* tags, jint tag_count) {
1522 _env = env;
1523 _tags = (jlong*)tags;
1524 _tag_count = tag_count;
1525 _object_results = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<jobject>(1,true);
1526 _tag_results = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<uint64_t>(1,true);
1527 }
1528
1529 ~TagObjectCollector() {
1530 delete _object_results;
1531 delete _tag_results;
1532 }
1533
1534 // for each tagged object check if the tag value matches
1535 // - if it matches then we create a JNI local reference to the object
1536 // and record the reference and tag value.
1537 //
1538 void do_entry(JvmtiTagHashmapEntry* entry) {
1539 for (int i=0; i<_tag_count; i++) {
1540 if (_tags[i] == entry->tag()) {
1541 // The reference in this tag map could be the only (implicitly weak)
1542 // reference to that object. If we hand it out, we need to keep it live wrt
1543 // SATB marking similar to other j.l.ref.Reference referents. This is
1544 // achieved by using a phantom load in the object() accessor.
1545 oop o = entry->object();
1546 assert(o != NULL && Universe::heap()->is_in_reserved(o), "sanity check");
1547 jobject ref = JNIHandles::make_local(JavaThread::current(), o);
1548 _object_results->append(ref);
1549 _tag_results->append((uint64_t)entry->tag());
1550 }
1551 }
1552 }
1553
1554 // return the results from the collection
1555 //
1556 jvmtiError result(jint* count_ptr, jobject** object_result_ptr, jlong** tag_result_ptr) {
1557 jvmtiError error;
1558 int count = _object_results->length();
1559 assert(count >= 0, "sanity check");
1560
1561 // if object_result_ptr is not NULL then allocate the result and copy
1562 // in the object references.
1563 if (object_result_ptr != NULL) {
1564 error = _env->Allocate(count * sizeof(jobject), (unsigned char**)object_result_ptr);
1565 if (error != JVMTI_ERROR_NONE) {
1566 return error;
1567 }
1568 for (int i=0; i<count; i++) {
1569 (*object_result_ptr)[i] = _object_results->at(i);
1570 }
1571 }
1572
1573 // if tag_result_ptr is not NULL then allocate the result and copy
1574 // in the tag values.
1575 if (tag_result_ptr != NULL) {
1576 error = _env->Allocate(count * sizeof(jlong), (unsigned char**)tag_result_ptr);
1577 if (error != JVMTI_ERROR_NONE) {
1578 if (object_result_ptr != NULL) {
1579 _env->Deallocate((unsigned char*)object_result_ptr);
1580 }
1581 return error;
1582 }
1583 for (int i=0; i<count; i++) {
1584 (*tag_result_ptr)[i] = (jlong)_tag_results->at(i);
1585 }
1586 }
1587
1588 *count_ptr = count;
1589 return JVMTI_ERROR_NONE;
1590 }
1591 };
1592
1593 // return the list of objects with the specified tags
1594 jvmtiError JvmtiTagMap::get_objects_with_tags(const jlong* tags,
1595 jint count, jint* count_ptr, jobject** object_result_ptr, jlong** tag_result_ptr) {
1596
1597 TagObjectCollector collector(env(), tags, count);
1598 {
1599 // iterate over all tagged objects
1600 MutexLocker ml(lock());
1601 entry_iterate(&collector);
1602 }
1603 return collector.result(count_ptr, object_result_ptr, tag_result_ptr);
1604 }
1605
1606
1607 // ObjectMarker is used to support the marking objects when walking the
1608 // heap.
1609 //
1610 // This implementation uses the existing mark bits in an object for
1611 // marking. Objects that are marked must later have their headers restored.
1612 // As most objects are unlocked and don't have their identity hash computed
1613 // we don't have to save their headers. Instead we save the headers that
1614 // are "interesting". Later when the headers are restored this implementation
1615 // restores all headers to their initial value and then restores the few
1616 // objects that had interesting headers.
1617 //
1618 // Future work: This implementation currently uses growable arrays to save
1619 // the oop and header of interesting objects. As an optimization we could
1620 // use the same technique as the GC and make use of the unused area
1621 // between top() and end().
1622 //
1623
1624 // An ObjectClosure used to restore the mark bits of an object
1625 class RestoreMarksClosure : public ObjectClosure {
1626 public:
1627 void do_object(oop o) {
1628 if (o != NULL) {
1629 markOop mark = o->mark();
1630 if (mark->is_marked()) {
1631 o->init_mark();
1632 }
1633 }
1634 }
1635 };
1636
1637 // ObjectMarker provides the mark and visited functions
1638 class ObjectMarker : AllStatic {
1639 private:
1640 // saved headers
1641 static GrowableArray<oop>* _saved_oop_stack;
1642 static GrowableArray<markOop>* _saved_mark_stack;
1643 static bool _needs_reset; // do we need to reset mark bits?
1644
1645 public:
1646 static void init(); // initialize
1647 static void done(); // clean-up
1648
1649 static inline void mark(oop o); // mark an object
1650 static inline bool visited(oop o); // check if object has been visited
1651
1652 static inline bool needs_reset() { return _needs_reset; }
1653 static inline void set_needs_reset(bool v) { _needs_reset = v; }
1654 };
1655
1656 GrowableArray<oop>* ObjectMarker::_saved_oop_stack = NULL;
1657 GrowableArray<markOop>* ObjectMarker::_saved_mark_stack = NULL;
1658 bool ObjectMarker::_needs_reset = true; // need to reset mark bits by default
1659
1660 // initialize ObjectMarker - prepares for object marking
1661 void ObjectMarker::init() {
1662 assert(Thread::current()->is_VM_thread(), "must be VMThread");
1663
1664 // prepare heap for iteration
1665 Universe::heap()->ensure_parsability(false); // no need to retire TLABs
1666
1667 // create stacks for interesting headers
1668 _saved_mark_stack = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<markOop>(4000, true);
1669 _saved_oop_stack = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<oop>(4000, true);
1670
1671 if (UseBiasedLocking) {
1672 BiasedLocking::preserve_marks();
1673 }
1674 }
1675
1676 // Object marking is done so restore object headers
1677 void ObjectMarker::done() {
1678 // iterate over all objects and restore the mark bits to
1679 // their initial value
1680 RestoreMarksClosure blk;
1681 if (needs_reset()) {
1682 Universe::heap()->object_iterate(&blk);
1683 } else {
1684 // We don't need to reset mark bits on this call, but reset the
1685 // flag to the default for the next call.
1686 set_needs_reset(true);
1687 }
1688
1689 // now restore the interesting headers
1690 for (int i = 0; i < _saved_oop_stack->length(); i++) {
1691 oop o = _saved_oop_stack->at(i);
1692 markOop mark = _saved_mark_stack->at(i);
1693 o->set_mark(mark);
1694 }
1695
1696 if (UseBiasedLocking) {
1697 BiasedLocking::restore_marks();
1698 }
1699
1700 // free the stacks
1701 delete _saved_oop_stack;
1702 delete _saved_mark_stack;
1703 }
1704
1705 // mark an object
1706 inline void ObjectMarker::mark(oop o) {
1707 assert(Universe::heap()->is_in(o), "sanity check");
1708 assert(!o->mark()->is_marked(), "should only mark an object once");
1709
1710 // object's mark word
1711 markOop mark = o->mark();
1712
1713 if (mark->must_be_preserved(o)) {
1714 _saved_mark_stack->push(mark);
1715 _saved_oop_stack->push(o);
1716 }
1717
1718 // mark the object
1719 o->set_mark(markOopDesc::prototype()->set_marked());
1720 }
1721
1722 // return true if object is marked
1723 inline bool ObjectMarker::visited(oop o) {
1724 return o->mark()->is_marked();
1725 }
1726
1727 // Stack allocated class to help ensure that ObjectMarker is used
1728 // correctly. Constructor initializes ObjectMarker, destructor calls
1729 // ObjectMarker's done() function to restore object headers.
1730 class ObjectMarkerController : public StackObj {
1731 public:
1732 ObjectMarkerController() {
1733 ObjectMarker::init();
1734 }
1735 ~ObjectMarkerController() {
1736 ObjectMarker::done();
1737 }
1738 };
1739
1740
1741 // helper to map a jvmtiHeapReferenceKind to an old style jvmtiHeapRootKind
1742 // (not performance critical as only used for roots)
1743 static jvmtiHeapRootKind toJvmtiHeapRootKind(jvmtiHeapReferenceKind kind) {
1744 switch (kind) {
1745 case JVMTI_HEAP_REFERENCE_JNI_GLOBAL: return JVMTI_HEAP_ROOT_JNI_GLOBAL;
1746 case JVMTI_HEAP_REFERENCE_SYSTEM_CLASS: return JVMTI_HEAP_ROOT_SYSTEM_CLASS;
1747 case JVMTI_HEAP_REFERENCE_MONITOR: return JVMTI_HEAP_ROOT_MONITOR;
1748 case JVMTI_HEAP_REFERENCE_STACK_LOCAL: return JVMTI_HEAP_ROOT_STACK_LOCAL;
1749 case JVMTI_HEAP_REFERENCE_JNI_LOCAL: return JVMTI_HEAP_ROOT_JNI_LOCAL;
1750 case JVMTI_HEAP_REFERENCE_THREAD: return JVMTI_HEAP_ROOT_THREAD;
1751 case JVMTI_HEAP_REFERENCE_OTHER: return JVMTI_HEAP_ROOT_OTHER;
1752 default: ShouldNotReachHere(); return JVMTI_HEAP_ROOT_OTHER;
1753 }
1754 }
1755
1756 // Base class for all heap walk contexts. The base class maintains a flag
1757 // to indicate if the context is valid or not.
1758 class HeapWalkContext {
1759 private:
1760 bool _valid;
1761 public:
1762 HeapWalkContext(bool valid) { _valid = valid; }
1763 void invalidate() { _valid = false; }
1764 bool is_valid() const { return _valid; }
1765 };
1766
1767 // A basic heap walk context for the deprecated heap walking functions.
1768 // The context for a basic heap walk are the callbacks and fields used by
1769 // the referrer caching scheme.
1770 class BasicHeapWalkContext: public HeapWalkContext {
1771 private:
1772 jvmtiHeapRootCallback _heap_root_callback;
1773 jvmtiStackReferenceCallback _stack_ref_callback;
1774 jvmtiObjectReferenceCallback _object_ref_callback;
1775
1776 // used for caching
1777 oop _last_referrer;
1778 jlong _last_referrer_tag;
1779
1780 public:
1781 BasicHeapWalkContext() : HeapWalkContext(false) { }
1782
1783 BasicHeapWalkContext(jvmtiHeapRootCallback heap_root_callback,
1784 jvmtiStackReferenceCallback stack_ref_callback,
1785 jvmtiObjectReferenceCallback object_ref_callback) :
1786 HeapWalkContext(true),
1787 _heap_root_callback(heap_root_callback),
1788 _stack_ref_callback(stack_ref_callback),
1789 _object_ref_callback(object_ref_callback),
1790 _last_referrer(NULL),
1791 _last_referrer_tag(0) {
1792 }
1793
1794 // accessors
1795 jvmtiHeapRootCallback heap_root_callback() const { return _heap_root_callback; }
1796 jvmtiStackReferenceCallback stack_ref_callback() const { return _stack_ref_callback; }
1797 jvmtiObjectReferenceCallback object_ref_callback() const { return _object_ref_callback; }
1798
1799 oop last_referrer() const { return _last_referrer; }
1800 void set_last_referrer(oop referrer) { _last_referrer = referrer; }
1801 jlong last_referrer_tag() const { return _last_referrer_tag; }
1802 void set_last_referrer_tag(jlong value) { _last_referrer_tag = value; }
1803 };
1804
1805 // The advanced heap walk context for the FollowReferences functions.
1806 // The context is the callbacks, and the fields used for filtering.
1807 class AdvancedHeapWalkContext: public HeapWalkContext {
1808 private:
1809 jint _heap_filter;
1810 Klass* _klass_filter;
1811 const jvmtiHeapCallbacks* _heap_callbacks;
1812
1813 public:
1814 AdvancedHeapWalkContext() : HeapWalkContext(false) { }
1815
1816 AdvancedHeapWalkContext(jint heap_filter,
1817 Klass* klass_filter,
1818 const jvmtiHeapCallbacks* heap_callbacks) :
1819 HeapWalkContext(true),
1820 _heap_filter(heap_filter),
1821 _klass_filter(klass_filter),
1822 _heap_callbacks(heap_callbacks) {
1823 }
1824
1825 // accessors
1826 jint heap_filter() const { return _heap_filter; }
1827 Klass* klass_filter() const { return _klass_filter; }
1828
1829 const jvmtiHeapReferenceCallback heap_reference_callback() const {
1830 return _heap_callbacks->heap_reference_callback;
1831 };
1832 const jvmtiPrimitiveFieldCallback primitive_field_callback() const {
1833 return _heap_callbacks->primitive_field_callback;
1834 }
1835 const jvmtiArrayPrimitiveValueCallback array_primitive_value_callback() const {
1836 return _heap_callbacks->array_primitive_value_callback;
1837 }
1838 const jvmtiStringPrimitiveValueCallback string_primitive_value_callback() const {
1839 return _heap_callbacks->string_primitive_value_callback;
1840 }
1841 };
1842
1843 // The CallbackInvoker is a class with static functions that the heap walk can call
1844 // into to invoke callbacks. It works in one of two modes. The "basic" mode is
1845 // used for the deprecated IterateOverReachableObjects functions. The "advanced"
1846 // mode is for the newer FollowReferences function which supports a lot of
1847 // additional callbacks.
1848 class CallbackInvoker : AllStatic {
1849 private:
1850 // heap walk styles
1851 enum { basic, advanced };
1852 static int _heap_walk_type;
1853 static bool is_basic_heap_walk() { return _heap_walk_type == basic; }
1854 static bool is_advanced_heap_walk() { return _heap_walk_type == advanced; }
1855
1856 // context for basic style heap walk
1857 static BasicHeapWalkContext _basic_context;
1858 static BasicHeapWalkContext* basic_context() {
1859 assert(_basic_context.is_valid(), "invalid");
1860 return &_basic_context;
1861 }
1862
1863 // context for advanced style heap walk
1864 static AdvancedHeapWalkContext _advanced_context;
1865 static AdvancedHeapWalkContext* advanced_context() {
1866 assert(_advanced_context.is_valid(), "invalid");
1867 return &_advanced_context;
1868 }
1869
1870 // context needed for all heap walks
1871 static JvmtiTagMap* _tag_map;
1872 static const void* _user_data;
1873 static GrowableArray<oop>* _visit_stack;
1874
1875 // accessors
1876 static JvmtiTagMap* tag_map() { return _tag_map; }
1877 static const void* user_data() { return _user_data; }
1878 static GrowableArray<oop>* visit_stack() { return _visit_stack; }
1879
1880 // if the object hasn't been visited then push it onto the visit stack
1881 // so that it will be visited later
1882 static inline bool check_for_visit(oop obj) {
1883 if (!ObjectMarker::visited(obj)) visit_stack()->push(obj);
1884 return true;
1885 }
1886
1887 // invoke basic style callbacks
1888 static inline bool invoke_basic_heap_root_callback
1889 (jvmtiHeapRootKind root_kind, oop obj);
1890 static inline bool invoke_basic_stack_ref_callback
1891 (jvmtiHeapRootKind root_kind, jlong thread_tag, jint depth, jmethodID method,
1892 int slot, oop obj);
1893 static inline bool invoke_basic_object_reference_callback
1894 (jvmtiObjectReferenceKind ref_kind, oop referrer, oop referree, jint index);
1895
1896 // invoke advanced style callbacks
1897 static inline bool invoke_advanced_heap_root_callback
1898 (jvmtiHeapReferenceKind ref_kind, oop obj);
1899 static inline bool invoke_advanced_stack_ref_callback
1900 (jvmtiHeapReferenceKind ref_kind, jlong thread_tag, jlong tid, int depth,
1901 jmethodID method, jlocation bci, jint slot, oop obj);
1902 static inline bool invoke_advanced_object_reference_callback
1903 (jvmtiHeapReferenceKind ref_kind, oop referrer, oop referree, jint index);
1904
1905 // used to report the value of primitive fields
1906 static inline bool report_primitive_field
1907 (jvmtiHeapReferenceKind ref_kind, oop obj, jint index, address addr, char type);
1908
1909 public:
1910 // initialize for basic mode
1911 static void initialize_for_basic_heap_walk(JvmtiTagMap* tag_map,
1912 GrowableArray<oop>* visit_stack,
1913 const void* user_data,
1914 BasicHeapWalkContext context);
1915
1916 // initialize for advanced mode
1917 static void initialize_for_advanced_heap_walk(JvmtiTagMap* tag_map,
1918 GrowableArray<oop>* visit_stack,
1919 const void* user_data,
1920 AdvancedHeapWalkContext context);
1921
1922 // functions to report roots
1923 static inline bool report_simple_root(jvmtiHeapReferenceKind kind, oop o);
1924 static inline bool report_jni_local_root(jlong thread_tag, jlong tid, jint depth,
1925 jmethodID m, oop o);
1926 static inline bool report_stack_ref_root(jlong thread_tag, jlong tid, jint depth,
1927 jmethodID method, jlocation bci, jint slot, oop o);
1928
1929 // functions to report references
1930 static inline bool report_array_element_reference(oop referrer, oop referree, jint index);
1931 static inline bool report_class_reference(oop referrer, oop referree);
1932 static inline bool report_class_loader_reference(oop referrer, oop referree);
1933 static inline bool report_signers_reference(oop referrer, oop referree);
1934 static inline bool report_protection_domain_reference(oop referrer, oop referree);
1935 static inline bool report_superclass_reference(oop referrer, oop referree);
1936 static inline bool report_interface_reference(oop referrer, oop referree);
1937 static inline bool report_static_field_reference(oop referrer, oop referree, jint slot);
1938 static inline bool report_field_reference(oop referrer, oop referree, jint slot);
1939 static inline bool report_constant_pool_reference(oop referrer, oop referree, jint index);
1940 static inline bool report_primitive_array_values(oop array);
1941 static inline bool report_string_value(oop str);
1942 static inline bool report_primitive_instance_field(oop o, jint index, address value, char type);
1943 static inline bool report_primitive_static_field(oop o, jint index, address value, char type);
1944 };
1945
1946 // statics
1947 int CallbackInvoker::_heap_walk_type;
1948 BasicHeapWalkContext CallbackInvoker::_basic_context;
1949 AdvancedHeapWalkContext CallbackInvoker::_advanced_context;
1950 JvmtiTagMap* CallbackInvoker::_tag_map;
1951 const void* CallbackInvoker::_user_data;
1952 GrowableArray<oop>* CallbackInvoker::_visit_stack;
1953
1954 // initialize for basic heap walk (IterateOverReachableObjects et al)
1955 void CallbackInvoker::initialize_for_basic_heap_walk(JvmtiTagMap* tag_map,
1956 GrowableArray<oop>* visit_stack,
1957 const void* user_data,
1958 BasicHeapWalkContext context) {
1959 _tag_map = tag_map;
1960 _visit_stack = visit_stack;
1961 _user_data = user_data;
1962 _basic_context = context;
1963 _advanced_context.invalidate(); // will trigger assertion if used
1964 _heap_walk_type = basic;
1965 }
1966
1967 // initialize for advanced heap walk (FollowReferences)
1968 void CallbackInvoker::initialize_for_advanced_heap_walk(JvmtiTagMap* tag_map,
1969 GrowableArray<oop>* visit_stack,
1970 const void* user_data,
1971 AdvancedHeapWalkContext context) {
1972 _tag_map = tag_map;
1973 _visit_stack = visit_stack;
1974 _user_data = user_data;
1975 _advanced_context = context;
1976 _basic_context.invalidate(); // will trigger assertion if used
1977 _heap_walk_type = advanced;
1978 }
1979
1980
1981 // invoke basic style heap root callback
1982 inline bool CallbackInvoker::invoke_basic_heap_root_callback(jvmtiHeapRootKind root_kind, oop obj) {
1983 // if we heap roots should be reported
1984 jvmtiHeapRootCallback cb = basic_context()->heap_root_callback();
1985 if (cb == NULL) {
1986 return check_for_visit(obj);
1987 }
1988
1989 CallbackWrapper wrapper(tag_map(), obj);
1990 jvmtiIterationControl control = (*cb)(root_kind,
1991 wrapper.klass_tag(),
1992 wrapper.obj_size(),
1993 wrapper.obj_tag_p(),
1994 (void*)user_data());
1995 // push root to visit stack when following references
1996 if (control == JVMTI_ITERATION_CONTINUE &&
1997 basic_context()->object_ref_callback() != NULL) {
1998 visit_stack()->push(obj);
1999 }
2000 return control != JVMTI_ITERATION_ABORT;
2001 }
2002
2003 // invoke basic style stack ref callback
2004 inline bool CallbackInvoker::invoke_basic_stack_ref_callback(jvmtiHeapRootKind root_kind,
2005 jlong thread_tag,
2006 jint depth,
2007 jmethodID method,
2008 int slot,
2009 oop obj) {
2010 // if we stack refs should be reported
2011 jvmtiStackReferenceCallback cb = basic_context()->stack_ref_callback();
2012 if (cb == NULL) {
2013 return check_for_visit(obj);
2014 }
2015
2016 CallbackWrapper wrapper(tag_map(), obj);
2017 jvmtiIterationControl control = (*cb)(root_kind,
2018 wrapper.klass_tag(),
2019 wrapper.obj_size(),
2020 wrapper.obj_tag_p(),
2021 thread_tag,
2022 depth,
2023 method,
2024 slot,
2025 (void*)user_data());
2026 // push root to visit stack when following references
2027 if (control == JVMTI_ITERATION_CONTINUE &&
2028 basic_context()->object_ref_callback() != NULL) {
2029 visit_stack()->push(obj);
2030 }
2031 return control != JVMTI_ITERATION_ABORT;
2032 }
2033
2034 // invoke basic style object reference callback
2035 inline bool CallbackInvoker::invoke_basic_object_reference_callback(jvmtiObjectReferenceKind ref_kind,
2036 oop referrer,
2037 oop referree,
2038 jint index) {
2039
2040 BasicHeapWalkContext* context = basic_context();
2041
2042 // callback requires the referrer's tag. If it's the same referrer
2043 // as the last call then we use the cached value.
2044 jlong referrer_tag;
2045 if (referrer == context->last_referrer()) {
2046 referrer_tag = context->last_referrer_tag();
2047 } else {
2048 referrer_tag = tag_for(tag_map(), referrer);
2049 }
2050
2051 // do the callback
2052 CallbackWrapper wrapper(tag_map(), referree);
2053 jvmtiObjectReferenceCallback cb = context->object_ref_callback();
2054 jvmtiIterationControl control = (*cb)(ref_kind,
2055 wrapper.klass_tag(),
2056 wrapper.obj_size(),
2057 wrapper.obj_tag_p(),
2058 referrer_tag,
2059 index,
2060 (void*)user_data());
2061
2062 // record referrer and referrer tag. For self-references record the
2063 // tag value from the callback as this might differ from referrer_tag.
2064 context->set_last_referrer(referrer);
2065 if (referrer == referree) {
2066 context->set_last_referrer_tag(*wrapper.obj_tag_p());
2067 } else {
2068 context->set_last_referrer_tag(referrer_tag);
2069 }
2070
2071 if (control == JVMTI_ITERATION_CONTINUE) {
2072 return check_for_visit(referree);
2073 } else {
2074 return control != JVMTI_ITERATION_ABORT;
2075 }
2076 }
2077
2078 // invoke advanced style heap root callback
2079 inline bool CallbackInvoker::invoke_advanced_heap_root_callback(jvmtiHeapReferenceKind ref_kind,
2080 oop obj) {
2081 AdvancedHeapWalkContext* context = advanced_context();
2082
2083 // check that callback is provided
2084 jvmtiHeapReferenceCallback cb = context->heap_reference_callback();
2085 if (cb == NULL) {
2086 return check_for_visit(obj);
2087 }
2088
2089 // apply class filter
2090 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
2091 return check_for_visit(obj);
2092 }
2093
2094 // setup the callback wrapper
2095 CallbackWrapper wrapper(tag_map(), obj);
2096
2097 // apply tag filter
2098 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2099 wrapper.klass_tag(),
2100 context->heap_filter())) {
2101 return check_for_visit(obj);
2102 }
2103
2104 // for arrays we need the length, otherwise -1
2105 jint len = (jint)(obj->is_array() ? arrayOop(obj)->length() : -1);
2106
2107 // invoke the callback
2108 jint res = (*cb)(ref_kind,
2109 NULL, // referrer info
2110 wrapper.klass_tag(),
2111 0, // referrer_class_tag is 0 for heap root
2112 wrapper.obj_size(),
2113 wrapper.obj_tag_p(),
2114 NULL, // referrer_tag_p
2115 len,
2116 (void*)user_data());
2117 if (res & JVMTI_VISIT_ABORT) {
2118 return false;// referrer class tag
2119 }
2120 if (res & JVMTI_VISIT_OBJECTS) {
2121 check_for_visit(obj);
2122 }
2123 return true;
2124 }
2125
2126 // report a reference from a thread stack to an object
2127 inline bool CallbackInvoker::invoke_advanced_stack_ref_callback(jvmtiHeapReferenceKind ref_kind,
2128 jlong thread_tag,
2129 jlong tid,
2130 int depth,
2131 jmethodID method,
2132 jlocation bci,
2133 jint slot,
2134 oop obj) {
2135 AdvancedHeapWalkContext* context = advanced_context();
2136
2137 // check that callback is provider
2138 jvmtiHeapReferenceCallback cb = context->heap_reference_callback();
2139 if (cb == NULL) {
2140 return check_for_visit(obj);
2141 }
2142
2143 // apply class filter
2144 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
2145 return check_for_visit(obj);
2146 }
2147
2148 // setup the callback wrapper
2149 CallbackWrapper wrapper(tag_map(), obj);
2150
2151 // apply tag filter
2152 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2153 wrapper.klass_tag(),
2154 context->heap_filter())) {
2155 return check_for_visit(obj);
2156 }
2157
2158 // setup the referrer info
2159 jvmtiHeapReferenceInfo reference_info;
2160 reference_info.stack_local.thread_tag = thread_tag;
2161 reference_info.stack_local.thread_id = tid;
2162 reference_info.stack_local.depth = depth;
2163 reference_info.stack_local.method = method;
2164 reference_info.stack_local.location = bci;
2165 reference_info.stack_local.slot = slot;
2166
2167 // for arrays we need the length, otherwise -1
2168 jint len = (jint)(obj->is_array() ? arrayOop(obj)->length() : -1);
2169
2170 // call into the agent
2171 int res = (*cb)(ref_kind,
2172 &reference_info,
2173 wrapper.klass_tag(),
2174 0, // referrer_class_tag is 0 for heap root (stack)
2175 wrapper.obj_size(),
2176 wrapper.obj_tag_p(),
2177 NULL, // referrer_tag is 0 for root
2178 len,
2179 (void*)user_data());
2180
2181 if (res & JVMTI_VISIT_ABORT) {
2182 return false;
2183 }
2184 if (res & JVMTI_VISIT_OBJECTS) {
2185 check_for_visit(obj);
2186 }
2187 return true;
2188 }
2189
2190 // This mask is used to pass reference_info to a jvmtiHeapReferenceCallback
2191 // only for ref_kinds defined by the JVM TI spec. Otherwise, NULL is passed.
2192 #define REF_INFO_MASK ((1 << JVMTI_HEAP_REFERENCE_FIELD) \
2193 | (1 << JVMTI_HEAP_REFERENCE_STATIC_FIELD) \
2194 | (1 << JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT) \
2195 | (1 << JVMTI_HEAP_REFERENCE_CONSTANT_POOL) \
2196 | (1 << JVMTI_HEAP_REFERENCE_STACK_LOCAL) \
2197 | (1 << JVMTI_HEAP_REFERENCE_JNI_LOCAL))
2198
2199 // invoke the object reference callback to report a reference
2200 inline bool CallbackInvoker::invoke_advanced_object_reference_callback(jvmtiHeapReferenceKind ref_kind,
2201 oop referrer,
2202 oop obj,
2203 jint index)
2204 {
2205 // field index is only valid field in reference_info
2206 static jvmtiHeapReferenceInfo reference_info = { 0 };
2207
2208 AdvancedHeapWalkContext* context = advanced_context();
2209
2210 // check that callback is provider
2211 jvmtiHeapReferenceCallback cb = context->heap_reference_callback();
2212 if (cb == NULL) {
2213 return check_for_visit(obj);
2214 }
2215
2216 // apply class filter
2217 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
2218 return check_for_visit(obj);
2219 }
2220
2221 // setup the callback wrapper
2222 TwoOopCallbackWrapper wrapper(tag_map(), referrer, obj);
2223
2224 // apply tag filter
2225 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2226 wrapper.klass_tag(),
2227 context->heap_filter())) {
2228 return check_for_visit(obj);
2229 }
2230
2231 // field index is only valid field in reference_info
2232 reference_info.field.index = index;
2233
2234 // for arrays we need the length, otherwise -1
2235 jint len = (jint)(obj->is_array() ? arrayOop(obj)->length() : -1);
2236
2237 // invoke the callback
2238 int res = (*cb)(ref_kind,
2239 (REF_INFO_MASK & (1 << ref_kind)) ? &reference_info : NULL,
2240 wrapper.klass_tag(),
2241 wrapper.referrer_klass_tag(),
2242 wrapper.obj_size(),
2243 wrapper.obj_tag_p(),
2244 wrapper.referrer_tag_p(),
2245 len,
2246 (void*)user_data());
2247
2248 if (res & JVMTI_VISIT_ABORT) {
2249 return false;
2250 }
2251 if (res & JVMTI_VISIT_OBJECTS) {
2252 check_for_visit(obj);
2253 }
2254 return true;
2255 }
2256
2257 // report a "simple root"
2258 inline bool CallbackInvoker::report_simple_root(jvmtiHeapReferenceKind kind, oop obj) {
2259 assert(kind != JVMTI_HEAP_REFERENCE_STACK_LOCAL &&
2260 kind != JVMTI_HEAP_REFERENCE_JNI_LOCAL, "not a simple root");
2261
2262 if (is_basic_heap_walk()) {
2263 // map to old style root kind
2264 jvmtiHeapRootKind root_kind = toJvmtiHeapRootKind(kind);
2265 return invoke_basic_heap_root_callback(root_kind, obj);
2266 } else {
2267 assert(is_advanced_heap_walk(), "wrong heap walk type");
2268 return invoke_advanced_heap_root_callback(kind, obj);
2269 }
2270 }
2271
2272
2273 // invoke the primitive array values
2274 inline bool CallbackInvoker::report_primitive_array_values(oop obj) {
2275 assert(obj->is_typeArray(), "not a primitive array");
2276
2277 AdvancedHeapWalkContext* context = advanced_context();
2278 assert(context->array_primitive_value_callback() != NULL, "no callback");
2279
2280 // apply class filter
2281 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
2282 return true;
2283 }
2284
2285 CallbackWrapper wrapper(tag_map(), obj);
2286
2287 // apply tag filter
2288 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2289 wrapper.klass_tag(),
2290 context->heap_filter())) {
2291 return true;
2292 }
2293
2294 // invoke the callback
2295 int res = invoke_array_primitive_value_callback(context->array_primitive_value_callback(),
2296 &wrapper,
2297 obj,
2298 (void*)user_data());
2299 return (!(res & JVMTI_VISIT_ABORT));
2300 }
2301
2302 // invoke the string value callback
2303 inline bool CallbackInvoker::report_string_value(oop str) {
2304 assert(str->klass() == SystemDictionary::String_klass(), "not a string");
2305
2306 AdvancedHeapWalkContext* context = advanced_context();
2307 assert(context->string_primitive_value_callback() != NULL, "no callback");
2308
2309 // apply class filter
2310 if (is_filtered_by_klass_filter(str, context->klass_filter())) {
2311 return true;
2312 }
2313
2314 CallbackWrapper wrapper(tag_map(), str);
2315
2316 // apply tag filter
2317 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2318 wrapper.klass_tag(),
2319 context->heap_filter())) {
2320 return true;
2321 }
2322
2323 // invoke the callback
2324 int res = invoke_string_value_callback(context->string_primitive_value_callback(),
2325 &wrapper,
2326 str,
2327 (void*)user_data());
2328 return (!(res & JVMTI_VISIT_ABORT));
2329 }
2330
2331 // invoke the primitive field callback
2332 inline bool CallbackInvoker::report_primitive_field(jvmtiHeapReferenceKind ref_kind,
2333 oop obj,
2334 jint index,
2335 address addr,
2336 char type)
2337 {
2338 // for primitive fields only the index will be set
2339 static jvmtiHeapReferenceInfo reference_info = { 0 };
2340
2341 AdvancedHeapWalkContext* context = advanced_context();
2342 assert(context->primitive_field_callback() != NULL, "no callback");
2343
2344 // apply class filter
2345 if (is_filtered_by_klass_filter(obj, context->klass_filter())) {
2346 return true;
2347 }
2348
2349 CallbackWrapper wrapper(tag_map(), obj);
2350
2351 // apply tag filter
2352 if (is_filtered_by_heap_filter(wrapper.obj_tag(),
2353 wrapper.klass_tag(),
2354 context->heap_filter())) {
2355 return true;
2356 }
2357
2358 // the field index in the referrer
2359 reference_info.field.index = index;
2360
2361 // map the type
2362 jvmtiPrimitiveType value_type = (jvmtiPrimitiveType)type;
2363
2364 // setup the jvalue
2365 jvalue value;
2366 copy_to_jvalue(&value, addr, value_type);
2367
2368 jvmtiPrimitiveFieldCallback cb = context->primitive_field_callback();
2369 int res = (*cb)(ref_kind,
2370 &reference_info,
2371 wrapper.klass_tag(),
2372 wrapper.obj_tag_p(),
2373 value,
2374 value_type,
2375 (void*)user_data());
2376 return (!(res & JVMTI_VISIT_ABORT));
2377 }
2378
2379
2380 // instance field
2381 inline bool CallbackInvoker::report_primitive_instance_field(oop obj,
2382 jint index,
2383 address value,
2384 char type) {
2385 return report_primitive_field(JVMTI_HEAP_REFERENCE_FIELD,
2386 obj,
2387 index,
2388 value,
2389 type);
2390 }
2391
2392 // static field
2393 inline bool CallbackInvoker::report_primitive_static_field(oop obj,
2394 jint index,
2395 address value,
2396 char type) {
2397 return report_primitive_field(JVMTI_HEAP_REFERENCE_STATIC_FIELD,
2398 obj,
2399 index,
2400 value,
2401 type);
2402 }
2403
2404 // report a JNI local (root object) to the profiler
2405 inline bool CallbackInvoker::report_jni_local_root(jlong thread_tag, jlong tid, jint depth, jmethodID m, oop obj) {
2406 if (is_basic_heap_walk()) {
2407 return invoke_basic_stack_ref_callback(JVMTI_HEAP_ROOT_JNI_LOCAL,
2408 thread_tag,
2409 depth,
2410 m,
2411 -1,
2412 obj);
2413 } else {
2414 return invoke_advanced_stack_ref_callback(JVMTI_HEAP_REFERENCE_JNI_LOCAL,
2415 thread_tag, tid,
2416 depth,
2417 m,
2418 (jlocation)-1,
2419 -1,
2420 obj);
2421 }
2422 }
2423
2424
2425 // report a local (stack reference, root object)
2426 inline bool CallbackInvoker::report_stack_ref_root(jlong thread_tag,
2427 jlong tid,
2428 jint depth,
2429 jmethodID method,
2430 jlocation bci,
2431 jint slot,
2432 oop obj) {
2433 if (is_basic_heap_walk()) {
2434 return invoke_basic_stack_ref_callback(JVMTI_HEAP_ROOT_STACK_LOCAL,
2435 thread_tag,
2436 depth,
2437 method,
2438 slot,
2439 obj);
2440 } else {
2441 return invoke_advanced_stack_ref_callback(JVMTI_HEAP_REFERENCE_STACK_LOCAL,
2442 thread_tag,
2443 tid,
2444 depth,
2445 method,
2446 bci,
2447 slot,
2448 obj);
2449 }
2450 }
2451
2452 // report an object referencing a class.
2453 inline bool CallbackInvoker::report_class_reference(oop referrer, oop referree) {
2454 if (is_basic_heap_walk()) {
2455 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CLASS, referrer, referree, -1);
2456 } else {
2457 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_CLASS, referrer, referree, -1);
2458 }
2459 }
2460
2461 // report a class referencing its class loader.
2462 inline bool CallbackInvoker::report_class_loader_reference(oop referrer, oop referree) {
2463 if (is_basic_heap_walk()) {
2464 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CLASS_LOADER, referrer, referree, -1);
2465 } else {
2466 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_CLASS_LOADER, referrer, referree, -1);
2467 }
2468 }
2469
2470 // report a class referencing its signers.
2471 inline bool CallbackInvoker::report_signers_reference(oop referrer, oop referree) {
2472 if (is_basic_heap_walk()) {
2473 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_SIGNERS, referrer, referree, -1);
2474 } else {
2475 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_SIGNERS, referrer, referree, -1);
2476 }
2477 }
2478
2479 // report a class referencing its protection domain..
2480 inline bool CallbackInvoker::report_protection_domain_reference(oop referrer, oop referree) {
2481 if (is_basic_heap_walk()) {
2482 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_PROTECTION_DOMAIN, referrer, referree, -1);
2483 } else {
2484 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_PROTECTION_DOMAIN, referrer, referree, -1);
2485 }
2486 }
2487
2488 // report a class referencing its superclass.
2489 inline bool CallbackInvoker::report_superclass_reference(oop referrer, oop referree) {
2490 if (is_basic_heap_walk()) {
2491 // Send this to be consistent with past implementation
2492 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CLASS, referrer, referree, -1);
2493 } else {
2494 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_SUPERCLASS, referrer, referree, -1);
2495 }
2496 }
2497
2498 // report a class referencing one of its interfaces.
2499 inline bool CallbackInvoker::report_interface_reference(oop referrer, oop referree) {
2500 if (is_basic_heap_walk()) {
2501 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_INTERFACE, referrer, referree, -1);
2502 } else {
2503 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_INTERFACE, referrer, referree, -1);
2504 }
2505 }
2506
2507 // report a class referencing one of its static fields.
2508 inline bool CallbackInvoker::report_static_field_reference(oop referrer, oop referree, jint slot) {
2509 if (is_basic_heap_walk()) {
2510 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_STATIC_FIELD, referrer, referree, slot);
2511 } else {
2512 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_STATIC_FIELD, referrer, referree, slot);
2513 }
2514 }
2515
2516 // report an array referencing an element object
2517 inline bool CallbackInvoker::report_array_element_reference(oop referrer, oop referree, jint index) {
2518 if (is_basic_heap_walk()) {
2519 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_ARRAY_ELEMENT, referrer, referree, index);
2520 } else {
2521 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT, referrer, referree, index);
2522 }
2523 }
2524
2525 // report an object referencing an instance field object
2526 inline bool CallbackInvoker::report_field_reference(oop referrer, oop referree, jint slot) {
2527 if (is_basic_heap_walk()) {
2528 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_FIELD, referrer, referree, slot);
2529 } else {
2530 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_FIELD, referrer, referree, slot);
2531 }
2532 }
2533
2534 // report an array referencing an element object
2535 inline bool CallbackInvoker::report_constant_pool_reference(oop referrer, oop referree, jint index) {
2536 if (is_basic_heap_walk()) {
2537 return invoke_basic_object_reference_callback(JVMTI_REFERENCE_CONSTANT_POOL, referrer, referree, index);
2538 } else {
2539 return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_CONSTANT_POOL, referrer, referree, index);
2540 }
2541 }
2542
2543 // A supporting closure used to process simple roots
2544 class SimpleRootsClosure : public OopClosure {
2545 private:
2546 jvmtiHeapReferenceKind _kind;
2547 bool _continue;
2548
2549 jvmtiHeapReferenceKind root_kind() { return _kind; }
2550
2551 public:
2552 void set_kind(jvmtiHeapReferenceKind kind) {
2553 _kind = kind;
2554 _continue = true;
2555 }
2556
2557 inline bool stopped() {
2558 return !_continue;
2559 }
2560
2561 void do_oop(oop* obj_p) {
2562 // iteration has terminated
2563 if (stopped()) {
2564 return;
2565 }
2566
2567 oop o = *obj_p;
2568 // ignore null
2569 if (o == NULL) {
2570 return;
2571 }
2572
2573 assert(Universe::heap()->is_in_reserved(o), "should be impossible");
2574
2575 jvmtiHeapReferenceKind kind = root_kind();
2576 if (kind == JVMTI_HEAP_REFERENCE_SYSTEM_CLASS) {
2577 // SystemDictionary::always_strong_oops_do reports the application
2578 // class loader as a root. We want this root to be reported as
2579 // a root kind of "OTHER" rather than "SYSTEM_CLASS".
2580 if (!o->is_instance() || !InstanceKlass::cast(o->klass())->is_mirror_instance_klass()) {
2581 kind = JVMTI_HEAP_REFERENCE_OTHER;
2582 }
2583 }
2584
2585 // invoke the callback
2586 _continue = CallbackInvoker::report_simple_root(kind, o);
2587
2588 }
2589 virtual void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }
2590 };
2591
2592 // A supporting closure used to process JNI locals
2593 class JNILocalRootsClosure : public OopClosure {
2594 private:
2595 jlong _thread_tag;
2596 jlong _tid;
2597 jint _depth;
2598 jmethodID _method;
2599 bool _continue;
2600 public:
2601 void set_context(jlong thread_tag, jlong tid, jint depth, jmethodID method) {
2602 _thread_tag = thread_tag;
2603 _tid = tid;
2604 _depth = depth;
2605 _method = method;
2606 _continue = true;
2607 }
2608
2609 inline bool stopped() {
2610 return !_continue;
2611 }
2612
2613 void do_oop(oop* obj_p) {
2614 // iteration has terminated
2615 if (stopped()) {
2616 return;
2617 }
2618
2619 oop o = *obj_p;
2620 // ignore null
2621 if (o == NULL) {
2622 return;
2623 }
2624
2625 // invoke the callback
2626 _continue = CallbackInvoker::report_jni_local_root(_thread_tag, _tid, _depth, _method, o);
2627 }
2628 virtual void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }
2629 };
2630
2631
2632 // A VM operation to iterate over objects that are reachable from
2633 // a set of roots or an initial object.
2634 //
2635 // For VM_HeapWalkOperation the set of roots used is :-
2636 //
2637 // - All JNI global references
2638 // - All inflated monitors
2639 // - All classes loaded by the boot class loader (or all classes
2640 // in the event that class unloading is disabled)
2641 // - All java threads
2642 // - For each java thread then all locals and JNI local references
2643 // on the thread's execution stack
2644 // - All visible/explainable objects from Universes::oops_do
2645 //
2646 class VM_HeapWalkOperation: public VM_Operation {
2647 private:
2648 enum {
2649 initial_visit_stack_size = 4000
2650 };
2651
2652 bool _is_advanced_heap_walk; // indicates FollowReferences
2653 JvmtiTagMap* _tag_map;
2654 Handle _initial_object;
2655 GrowableArray<oop>* _visit_stack; // the visit stack
2656
2657 bool _collecting_heap_roots; // are we collecting roots
2658 bool _following_object_refs; // are we following object references
2659
2660 bool _reporting_primitive_fields; // optional reporting
2661 bool _reporting_primitive_array_values;
2662 bool _reporting_string_values;
2663
2664 GrowableArray<oop>* create_visit_stack() {
2665 return new (ResourceObj::C_HEAP, mtInternal) GrowableArray<oop>(initial_visit_stack_size, true);
2666 }
2667
2668 // accessors
2669 bool is_advanced_heap_walk() const { return _is_advanced_heap_walk; }
2670 JvmtiTagMap* tag_map() const { return _tag_map; }
2671 Handle initial_object() const { return _initial_object; }
2672
2673 bool is_following_references() const { return _following_object_refs; }
2674
2675 bool is_reporting_primitive_fields() const { return _reporting_primitive_fields; }
2676 bool is_reporting_primitive_array_values() const { return _reporting_primitive_array_values; }
2677 bool is_reporting_string_values() const { return _reporting_string_values; }
2678
2679 GrowableArray<oop>* visit_stack() const { return _visit_stack; }
2680
2681 // iterate over the various object types
2682 inline bool iterate_over_array(oop o);
2683 inline bool iterate_over_type_array(oop o);
2684 inline bool iterate_over_class(oop o);
2685 inline bool iterate_over_object(oop o);
2686
2687 // root collection
2688 inline bool collect_simple_roots();
2689 inline bool collect_stack_roots();
2690 inline bool collect_stack_roots(JavaThread* java_thread, JNILocalRootsClosure* blk);
2691
2692 // visit an object
2693 inline bool visit(oop o);
2694
2695 public:
2696 VM_HeapWalkOperation(JvmtiTagMap* tag_map,
2697 Handle initial_object,
2698 BasicHeapWalkContext callbacks,
2699 const void* user_data);
2700
2701 VM_HeapWalkOperation(JvmtiTagMap* tag_map,
2702 Handle initial_object,
2703 AdvancedHeapWalkContext callbacks,
2704 const void* user_data);
2705
2706 ~VM_HeapWalkOperation();
2707
2708 VMOp_Type type() const { return VMOp_HeapWalkOperation; }
2709 void doit();
2710 };
2711
2712
2713 VM_HeapWalkOperation::VM_HeapWalkOperation(JvmtiTagMap* tag_map,
2714 Handle initial_object,
2715 BasicHeapWalkContext callbacks,
2716 const void* user_data) {
2717 _is_advanced_heap_walk = false;
2718 _tag_map = tag_map;
2719 _initial_object = initial_object;
2720 _following_object_refs = (callbacks.object_ref_callback() != NULL);
2721 _reporting_primitive_fields = false;
2722 _reporting_primitive_array_values = false;
2723 _reporting_string_values = false;
2724 _visit_stack = create_visit_stack();
2725
2726
2727 CallbackInvoker::initialize_for_basic_heap_walk(tag_map, _visit_stack, user_data, callbacks);
2728 }
2729
2730 VM_HeapWalkOperation::VM_HeapWalkOperation(JvmtiTagMap* tag_map,
2731 Handle initial_object,
2732 AdvancedHeapWalkContext callbacks,
2733 const void* user_data) {
2734 _is_advanced_heap_walk = true;
2735 _tag_map = tag_map;
2736 _initial_object = initial_object;
2737 _following_object_refs = true;
2738 _reporting_primitive_fields = (callbacks.primitive_field_callback() != NULL);;
2739 _reporting_primitive_array_values = (callbacks.array_primitive_value_callback() != NULL);;
2740 _reporting_string_values = (callbacks.string_primitive_value_callback() != NULL);;
2741 _visit_stack = create_visit_stack();
2742
2743 CallbackInvoker::initialize_for_advanced_heap_walk(tag_map, _visit_stack, user_data, callbacks);
2744 }
2745
2746 VM_HeapWalkOperation::~VM_HeapWalkOperation() {
2747 if (_following_object_refs) {
2748 assert(_visit_stack != NULL, "checking");
2749 delete _visit_stack;
2750 _visit_stack = NULL;
2751 }
2752 }
2753
2754 // an array references its class and has a reference to
2755 // each element in the array
2756 inline bool VM_HeapWalkOperation::iterate_over_array(oop o) {
2757 objArrayOop array = objArrayOop(o);
2758
2759 // array reference to its class
2760 oop mirror = ObjArrayKlass::cast(array->klass())->java_mirror();
2761 if (!CallbackInvoker::report_class_reference(o, mirror)) {
2762 return false;
2763 }
2764
2765 // iterate over the array and report each reference to a
2766 // non-null element
2767 for (int index=0; index<array->length(); index++) {
2768 oop elem = array->obj_at(index);
2769 if (elem == NULL) {
2770 continue;
2771 }
2772
2773 // report the array reference o[index] = elem
2774 if (!CallbackInvoker::report_array_element_reference(o, elem, index)) {
2775 return false;
2776 }
2777 }
2778 return true;
2779 }
2780
2781 // a type array references its class
2782 inline bool VM_HeapWalkOperation::iterate_over_type_array(oop o) {
2783 Klass* k = o->klass();
2784 oop mirror = k->java_mirror();
2785 if (!CallbackInvoker::report_class_reference(o, mirror)) {
2786 return false;
2787 }
2788
2789 // report the array contents if required
2790 if (is_reporting_primitive_array_values()) {
2791 if (!CallbackInvoker::report_primitive_array_values(o)) {
2792 return false;
2793 }
2794 }
2795 return true;
2796 }
2797
2798 #ifdef ASSERT
2799 // verify that a static oop field is in range
2800 static inline bool verify_static_oop(InstanceKlass* ik,
2801 oop mirror, int offset) {
2802 address obj_p = (address)mirror + offset;
2803 address start = (address)InstanceMirrorKlass::start_of_static_fields(mirror);
2804 address end = start + (java_lang_Class::static_oop_field_count(mirror) * heapOopSize);
2805 assert(end >= start, "sanity check");
2806
2807 if (obj_p >= start && obj_p < end) {
2808 return true;
2809 } else {
2810 return false;
2811 }
2812 }
2813 #endif // #ifdef ASSERT
2814
2815 // a class references its super class, interfaces, class loader, ...
2816 // and finally its static fields
2817 inline bool VM_HeapWalkOperation::iterate_over_class(oop java_class) {
2818 int i;
2819 Klass* klass = java_lang_Class::as_Klass(java_class);
2820
2821 if (klass->is_instance_klass()) {
2822 InstanceKlass* ik = InstanceKlass::cast(klass);
2823
2824 // Ignore the class if it hasn't been initialized yet
2825 if (!ik->is_linked()) {
2826 return true;
2827 }
2828
2829 // get the java mirror
2830 oop mirror = klass->java_mirror();
2831
2832 // super (only if something more interesting than java.lang.Object)
2833 Klass* java_super = ik->java_super();
2834 if (java_super != NULL && java_super != SystemDictionary::Object_klass()) {
2835 oop super = java_super->java_mirror();
2836 if (!CallbackInvoker::report_superclass_reference(mirror, super)) {
2837 return false;
2838 }
2839 }
2840
2841 // class loader
2842 oop cl = ik->class_loader();
2843 if (cl != NULL) {
2844 if (!CallbackInvoker::report_class_loader_reference(mirror, cl)) {
2845 return false;
2846 }
2847 }
2848
2849 // protection domain
2850 oop pd = ik->protection_domain();
2851 if (pd != NULL) {
2852 if (!CallbackInvoker::report_protection_domain_reference(mirror, pd)) {
2853 return false;
2854 }
2855 }
2856
2857 // signers
2858 oop signers = ik->signers();
2859 if (signers != NULL) {
2860 if (!CallbackInvoker::report_signers_reference(mirror, signers)) {
2861 return false;
2862 }
2863 }
2864
2865 // references from the constant pool
2866 {
2867 ConstantPool* pool = ik->constants();
2868 for (int i = 1; i < pool->length(); i++) {
2869 constantTag tag = pool->tag_at(i).value();
2870 if (tag.is_string() || tag.is_klass()) {
2871 oop entry;
2872 if (tag.is_string()) {
2873 entry = pool->resolved_string_at(i);
2874 // If the entry is non-null it is resolved.
2875 if (entry == NULL) continue;
2876 } else {
2877 entry = pool->resolved_klass_at(i)->java_mirror();
2878 }
2879 if (!CallbackInvoker::report_constant_pool_reference(mirror, entry, (jint)i)) {
2880 return false;
2881 }
2882 }
2883 }
2884 }
2885
2886 // interfaces
2887 // (These will already have been reported as references from the constant pool
2888 // but are specified by IterateOverReachableObjects and must be reported).
2889 Array<Klass*>* interfaces = ik->local_interfaces();
2890 for (i = 0; i < interfaces->length(); i++) {
2891 oop interf = ((Klass*)interfaces->at(i))->java_mirror();
2892 if (interf == NULL) {
2893 continue;
2894 }
2895 if (!CallbackInvoker::report_interface_reference(mirror, interf)) {
2896 return false;
2897 }
2898 }
2899
2900 // iterate over the static fields
2901
2902 ClassFieldMap* field_map = ClassFieldMap::create_map_of_static_fields(klass);
2903 for (i=0; i<field_map->field_count(); i++) {
2904 ClassFieldDescriptor* field = field_map->field_at(i);
2905 char type = field->field_type();
2906 if (!is_primitive_field_type(type)) {
2907 oop fld_o = mirror->obj_field(field->field_offset());
2908 assert(verify_static_oop(ik, mirror, field->field_offset()), "sanity check");
2909 if (fld_o != NULL) {
2910 int slot = field->field_index();
2911 if (!CallbackInvoker::report_static_field_reference(mirror, fld_o, slot)) {
2912 delete field_map;
2913 return false;
2914 }
2915 }
2916 } else {
2917 if (is_reporting_primitive_fields()) {
2918 address addr = (address)mirror + field->field_offset();
2919 int slot = field->field_index();
2920 if (!CallbackInvoker::report_primitive_static_field(mirror, slot, addr, type)) {
2921 delete field_map;
2922 return false;
2923 }
2924 }
2925 }
2926 }
2927 delete field_map;
2928
2929 return true;
2930 }
2931
2932 return true;
2933 }
2934
2935 // an object references a class and its instance fields
2936 // (static fields are ignored here as we report these as
2937 // references from the class).
2938 inline bool VM_HeapWalkOperation::iterate_over_object(oop o) {
2939 // reference to the class
2940 if (!CallbackInvoker::report_class_reference(o, o->klass()->java_mirror())) {
2941 return false;
2942 }
2943
2944 // iterate over instance fields
2945 ClassFieldMap* field_map = JvmtiCachedClassFieldMap::get_map_of_instance_fields(o);
2946 for (int i=0; i<field_map->field_count(); i++) {
2947 ClassFieldDescriptor* field = field_map->field_at(i);
2948 char type = field->field_type();
2949 if (!is_primitive_field_type(type)) {
2950 oop fld_o = o->obj_field(field->field_offset());
2951 // ignore any objects that aren't visible to profiler
2952 if (fld_o != NULL) {
2953 assert(Universe::heap()->is_in_reserved(fld_o), "unsafe code should not "
2954 "have references to Klass* anymore");
2955 int slot = field->field_index();
2956 if (!CallbackInvoker::report_field_reference(o, fld_o, slot)) {
2957 return false;
2958 }
2959 }
2960 } else {
2961 if (is_reporting_primitive_fields()) {
2962 // primitive instance field
2963 address addr = (address)o + field->field_offset();
2964 int slot = field->field_index();
2965 if (!CallbackInvoker::report_primitive_instance_field(o, slot, addr, type)) {
2966 return false;
2967 }
2968 }
2969 }
2970 }
2971
2972 // if the object is a java.lang.String
2973 if (is_reporting_string_values() &&
2974 o->klass() == SystemDictionary::String_klass()) {
2975 if (!CallbackInvoker::report_string_value(o)) {
2976 return false;
2977 }
2978 }
2979 return true;
2980 }
2981
2982
2983 // Collects all simple (non-stack) roots except for threads;
2984 // threads are handled in collect_stack_roots() as an optimization.
2985 // if there's a heap root callback provided then the callback is
2986 // invoked for each simple root.
2987 // if an object reference callback is provided then all simple
2988 // roots are pushed onto the marking stack so that they can be
2989 // processed later
2990 //
2991 inline bool VM_HeapWalkOperation::collect_simple_roots() {
2992 SimpleRootsClosure blk;
2993
2994 // JNI globals
2995 blk.set_kind(JVMTI_HEAP_REFERENCE_JNI_GLOBAL);
2996 JNIHandles::oops_do(&blk);
2997 if (blk.stopped()) {
2998 return false;
2999 }
3000
3001 // Preloaded classes and loader from the system dictionary
3002 blk.set_kind(JVMTI_HEAP_REFERENCE_SYSTEM_CLASS);
3003 SystemDictionary::always_strong_oops_do(&blk);
3004 ClassLoaderDataGraph::always_strong_oops_do(&blk, false);
3005 if (blk.stopped()) {
3006 return false;
3007 }
3008
3009 // Inflated monitors
3010 blk.set_kind(JVMTI_HEAP_REFERENCE_MONITOR);
3011 ObjectSynchronizer::oops_do(&blk);
3012 if (blk.stopped()) {
3013 return false;
3014 }
3015
3016 // threads are now handled in collect_stack_roots()
3017
3018 // Other kinds of roots maintained by HotSpot
3019 // Many of these won't be visible but others (such as instances of important
3020 // exceptions) will be visible.
3021 blk.set_kind(JVMTI_HEAP_REFERENCE_OTHER);
3022 Universe::oops_do(&blk);
3023
3024 // If there are any non-perm roots in the code cache, visit them.
3025 blk.set_kind(JVMTI_HEAP_REFERENCE_OTHER);
3026 CodeBlobToOopClosure look_in_blobs(&blk, !CodeBlobToOopClosure::FixRelocations);
3027 CodeCache::scavenge_root_nmethods_do(&look_in_blobs);
3028
3029 return true;
3030 }
3031
3032 // Walk the stack of a given thread and find all references (locals
3033 // and JNI calls) and report these as stack references
3034 inline bool VM_HeapWalkOperation::collect_stack_roots(JavaThread* java_thread,
3035 JNILocalRootsClosure* blk)
3036 {
3037 oop threadObj = java_thread->threadObj();
3038 assert(threadObj != NULL, "sanity check");
3039
3040 // only need to get the thread's tag once per thread
3041 jlong thread_tag = tag_for(_tag_map, threadObj);
3042
3043 // also need the thread id
3044 jlong tid = java_lang_Thread::thread_id(threadObj);
3045
3046
3047 if (java_thread->has_last_Java_frame()) {
3048
3049 // vframes are resource allocated
3050 Thread* current_thread = Thread::current();
3051 ResourceMark rm(current_thread);
3052 HandleMark hm(current_thread);
3053
3054 RegisterMap reg_map(java_thread);
3055 frame f = java_thread->last_frame();
3056 vframe* vf = vframe::new_vframe(&f, ®_map, java_thread);
3057
3058 bool is_top_frame = true;
3059 int depth = 0;
3060 frame* last_entry_frame = NULL;
3061
3062 while (vf != NULL) {
3063 if (vf->is_java_frame()) {
3064
3065 // java frame (interpreted, compiled, ...)
3066 javaVFrame *jvf = javaVFrame::cast(vf);
3067
3068 // the jmethodID
3069 jmethodID method = jvf->method()->jmethod_id();
3070
3071 if (!(jvf->method()->is_native())) {
3072 jlocation bci = (jlocation)jvf->bci();
3073 StackValueCollection* locals = jvf->locals();
3074 for (int slot=0; slot<locals->size(); slot++) {
3075 if (locals->at(slot)->type() == T_OBJECT) {
3076 oop o = locals->obj_at(slot)();
3077 if (o == NULL) {
3078 continue;
3079 }
3080
3081 // stack reference
3082 if (!CallbackInvoker::report_stack_ref_root(thread_tag, tid, depth, method,
3083 bci, slot, o)) {
3084 return false;
3085 }
3086 }
3087 }
3088
3089 StackValueCollection* exprs = jvf->expressions();
3090 for (int index=0; index < exprs->size(); index++) {
3091 if (exprs->at(index)->type() == T_OBJECT) {
3092 oop o = exprs->obj_at(index)();
3093 if (o == NULL) {
3094 continue;
3095 }
3096
3097 // stack reference
3098 if (!CallbackInvoker::report_stack_ref_root(thread_tag, tid, depth, method,
3099 bci, locals->size() + index, o)) {
3100 return false;
3101 }
3102 }
3103 }
3104
3105 // Follow oops from compiled nmethod
3106 if (jvf->cb() != NULL && jvf->cb()->is_nmethod()) {
3107 blk->set_context(thread_tag, tid, depth, method);
3108 jvf->cb()->as_nmethod()->oops_do(blk);
3109 }
3110 } else {
3111 blk->set_context(thread_tag, tid, depth, method);
3112 if (is_top_frame) {
3113 // JNI locals for the top frame.
3114 java_thread->active_handles()->oops_do(blk);
3115 } else {
3116 if (last_entry_frame != NULL) {
3117 // JNI locals for the entry frame
3118 assert(last_entry_frame->is_entry_frame(), "checking");
3119 last_entry_frame->entry_frame_call_wrapper()->handles()->oops_do(blk);
3120 }
3121 }
3122 }
3123 last_entry_frame = NULL;
3124 depth++;
3125 } else {
3126 // externalVFrame - for an entry frame then we report the JNI locals
3127 // when we find the corresponding javaVFrame
3128 frame* fr = vf->frame_pointer();
3129 assert(fr != NULL, "sanity check");
3130 if (fr->is_entry_frame()) {
3131 last_entry_frame = fr;
3132 }
3133 }
3134
3135 vf = vf->sender();
3136 is_top_frame = false;
3137 }
3138 } else {
3139 // no last java frame but there may be JNI locals
3140 blk->set_context(thread_tag, tid, 0, (jmethodID)NULL);
3141 java_thread->active_handles()->oops_do(blk);
3142 }
3143 return true;
3144 }
3145
3146
3147 // Collects the simple roots for all threads and collects all
3148 // stack roots - for each thread it walks the execution
3149 // stack to find all references and local JNI refs.
3150 inline bool VM_HeapWalkOperation::collect_stack_roots() {
3151 JNILocalRootsClosure blk;
3152 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thread = jtiwh.next(); ) {
3153 oop threadObj = thread->threadObj();
3154 if (threadObj != NULL && !thread->is_exiting() && !thread->is_hidden_from_external_view()) {
3155 // Collect the simple root for this thread before we
3156 // collect its stack roots
3157 if (!CallbackInvoker::report_simple_root(JVMTI_HEAP_REFERENCE_THREAD,
3158 threadObj)) {
3159 return false;
3160 }
3161 if (!collect_stack_roots(thread, &blk)) {
3162 return false;
3163 }
3164 }
3165 }
3166 return true;
3167 }
3168
3169 // visit an object
3170 // first mark the object as visited
3171 // second get all the outbound references from this object (in other words, all
3172 // the objects referenced by this object).
3173 //
3174 bool VM_HeapWalkOperation::visit(oop o) {
3175 // mark object as visited
3176 assert(!ObjectMarker::visited(o), "can't visit same object more than once");
3177 ObjectMarker::mark(o);
3178
3179 // instance
3180 if (o->is_instance()) {
3181 if (o->klass() == SystemDictionary::Class_klass()) {
3182 if (!java_lang_Class::is_primitive(o)) {
3183 // a java.lang.Class
3184 return iterate_over_class(o);
3185 }
3186 } else {
3187 return iterate_over_object(o);
3188 }
3189 }
3190
3191 // object array
3192 if (o->is_objArray()) {
3193 return iterate_over_array(o);
3194 }
3195
3196 // type array
3197 if (o->is_typeArray()) {
3198 return iterate_over_type_array(o);
3199 }
3200
3201 return true;
3202 }
3203
3204 void VM_HeapWalkOperation::doit() {
3205 ResourceMark rm;
3206 ObjectMarkerController marker;
3207 ClassFieldMapCacheMark cm;
3208
3209 assert(visit_stack()->is_empty(), "visit stack must be empty");
3210
3211 // the heap walk starts with an initial object or the heap roots
3212 if (initial_object().is_null()) {
3213 // If either collect_stack_roots() or collect_simple_roots()
3214 // returns false at this point, then there are no mark bits
3215 // to reset.
3216 ObjectMarker::set_needs_reset(false);
3217
3218 // Calling collect_stack_roots() before collect_simple_roots()
3219 // can result in a big performance boost for an agent that is
3220 // focused on analyzing references in the thread stacks.
3221 if (!collect_stack_roots()) return;
3222
3223 if (!collect_simple_roots()) return;
3224
3225 // no early return so enable heap traversal to reset the mark bits
3226 ObjectMarker::set_needs_reset(true);
3227 } else {
3228 visit_stack()->push(initial_object()());
3229 }
3230
3231 // object references required
3232 if (is_following_references()) {
3233
3234 // visit each object until all reachable objects have been
3235 // visited or the callback asked to terminate the iteration.
3236 while (!visit_stack()->is_empty()) {
3237 oop o = visit_stack()->pop();
3238 if (!ObjectMarker::visited(o)) {
3239 if (!visit(o)) {
3240 break;
3241 }
3242 }
3243 }
3244 }
3245 }
3246
3247 // iterate over all objects that are reachable from a set of roots
3248 void JvmtiTagMap::iterate_over_reachable_objects(jvmtiHeapRootCallback heap_root_callback,
3249 jvmtiStackReferenceCallback stack_ref_callback,
3250 jvmtiObjectReferenceCallback object_ref_callback,
3251 const void* user_data) {
3252 MutexLocker ml(Heap_lock);
3253 BasicHeapWalkContext context(heap_root_callback, stack_ref_callback, object_ref_callback);
3254 VM_HeapWalkOperation op(this, Handle(), context, user_data);
3255 VMThread::execute(&op);
3256 }
3257
3258 // iterate over all objects that are reachable from a given object
3259 void JvmtiTagMap::iterate_over_objects_reachable_from_object(jobject object,
3260 jvmtiObjectReferenceCallback object_ref_callback,
3261 const void* user_data) {
3262 oop obj = JNIHandles::resolve(object);
3263 Handle initial_object(Thread::current(), obj);
3264
3265 MutexLocker ml(Heap_lock);
3266 BasicHeapWalkContext context(NULL, NULL, object_ref_callback);
3267 VM_HeapWalkOperation op(this, initial_object, context, user_data);
3268 VMThread::execute(&op);
3269 }
3270
3271 // follow references from an initial object or the GC roots
3272 void JvmtiTagMap::follow_references(jint heap_filter,
3273 Klass* klass,
3274 jobject object,
3275 const jvmtiHeapCallbacks* callbacks,
3276 const void* user_data)
3277 {
3278 oop obj = JNIHandles::resolve(object);
3279 Handle initial_object(Thread::current(), obj);
3280
3281 MutexLocker ml(Heap_lock);
3282 AdvancedHeapWalkContext context(heap_filter, klass, callbacks);
3283 VM_HeapWalkOperation op(this, initial_object, context, user_data);
3284 VMThread::execute(&op);
3285 }
3286
3287
3288 void JvmtiTagMap::weak_oops_do(BoolObjectClosure* is_alive, OopClosure* f) {
3289 // No locks during VM bring-up (0 threads) and no safepoints after main
3290 // thread creation and before VMThread creation (1 thread); initial GC
3291 // verification can happen in that window which gets to here.
3292 assert(Threads::number_of_threads() <= 1 ||
3293 SafepointSynchronize::is_at_safepoint(),
3294 "must be executed at a safepoint");
3295 if (JvmtiEnv::environments_might_exist()) {
3296 JvmtiEnvIterator it;
3297 for (JvmtiEnvBase* env = it.first(); env != NULL; env = it.next(env)) {
3298 JvmtiTagMap* tag_map = env->tag_map();
3299 if (tag_map != NULL && !tag_map->is_empty()) {
3300 tag_map->do_weak_oops(is_alive, f);
3301 }
3302 }
3303 }
3304 }
3305
3306 void JvmtiTagMap::do_weak_oops(BoolObjectClosure* is_alive, OopClosure* f) {
3307
3308 // does this environment have the OBJECT_FREE event enabled
3309 bool post_object_free = env()->is_enabled(JVMTI_EVENT_OBJECT_FREE);
3310
3311 // counters used for trace message
3312 int freed = 0;
3313 int moved = 0;
3314
3315 JvmtiTagHashmap* hashmap = this->hashmap();
3316
3317 // reenable sizing (if disabled)
3318 hashmap->set_resizing_enabled(true);
3319
3320 // if the hashmap is empty then we can skip it
3321 if (hashmap->_entry_count == 0) {
3322 return;
3323 }
3324
3325 // now iterate through each entry in the table
3326
3327 JvmtiTagHashmapEntry** table = hashmap->table();
3328 int size = hashmap->size();
3329
3330 JvmtiTagHashmapEntry* delayed_add = NULL;
3331
3332 for (int pos = 0; pos < size; ++pos) {
3333 JvmtiTagHashmapEntry* entry = table[pos];
3334 JvmtiTagHashmapEntry* prev = NULL;
3335
3336 while (entry != NULL) {
3337 JvmtiTagHashmapEntry* next = entry->next();
3338
3339 // has object been GC'ed
3340 if (!is_alive->do_object_b(entry->object_peek())) {
3341 // grab the tag
3342 jlong tag = entry->tag();
3343 guarantee(tag != 0, "checking");
3344
3345 // remove GC'ed entry from hashmap and return the
3346 // entry to the free list
3347 hashmap->remove(prev, pos, entry);
3348 destroy_entry(entry);
3349
3350 // post the event to the profiler
3351 if (post_object_free) {
3352 JvmtiExport::post_object_free(env(), tag);
3353 }
3354
3355 ++freed;
3356 } else {
3357 f->do_oop(entry->object_addr());
3358 oop new_oop = entry->object_peek();
3359
3360 // if the object has moved then re-hash it and move its
3361 // entry to its new location.
3362 unsigned int new_pos = JvmtiTagHashmap::hash(new_oop, size);
3363 if (new_pos != (unsigned int)pos) {
3364 if (prev == NULL) {
3365 table[pos] = next;
3366 } else {
3367 prev->set_next(next);
3368 }
3369 if (new_pos < (unsigned int)pos) {
3370 entry->set_next(table[new_pos]);
3371 table[new_pos] = entry;
3372 } else {
3373 // Delay adding this entry to it's new position as we'd end up
3374 // hitting it again during this iteration.
3375 entry->set_next(delayed_add);
3376 delayed_add = entry;
3377 }
3378 moved++;
3379 } else {
3380 // object didn't move
3381 prev = entry;
3382 }
3383 }
3384
3385 entry = next;
3386 }
3387 }
3388
3389 // Re-add all the entries which were kept aside
3390 while (delayed_add != NULL) {
3391 JvmtiTagHashmapEntry* next = delayed_add->next();
3392 unsigned int pos = JvmtiTagHashmap::hash(delayed_add->object_peek(), size);
3393 delayed_add->set_next(table[pos]);
3394 table[pos] = delayed_add;
3395 delayed_add = next;
3396 }
3397
3398 log_debug(jvmti, objecttagging)("(%d->%d, %d freed, %d total moves)",
3399 hashmap->_entry_count + freed, hashmap->_entry_count, freed, moved);
3400 }